732dc9000822b432c32414af5d8a118891ec7da36b86bfbf5b461c00373bb016

en/5995.html.txt

@@ -0,0 +1,181 @@
+
+
+
+
+Leonardo da Vinci (English: /ˌliːəˈnɑːrdoʊ də ˈvɪntʃi, ˌliːoʊˈ-, ˌleɪoʊˈ-/;[a] 14/15 April 1452[b] – 2 May 1519),[4] was an Italian polymath of the High Renaissance who is widely considered one of the greatest painters of all time (despite less than 25 of his paintings having survived).[c] The Mona Lisa is the most famous of Leonardo's works and the most famous portrait ever made.[5] The Last Supper is the most reproduced religious painting of all time[6] and his Vitruvian Man drawing is also regarded as a cultural icon.[7] He is also known for his his notebooks, in which he made drawings and notes on science and invention; these involve a variety of subjects including anatomy, cartography, painting, and paleontology. Leonardo's collective works compose a contribution to later generations of artists rivalled only by that of his contemporary Michelangelo.[8]
+
+Properly named Leonardo di ser Piero da Vinci,[d] Leonardo was born out of wedlock to a notary, Piero da Vinci, and a peasant woman, Caterina, in Vinci, in the region of Florence, Italy. Leonardo was educated in the studio of the renowned Italian painter Andrea del Verrocchio. Much of his earlier working life was spent in the service of Ludovico il Moro in Milan, and he later worked in Rome, Bologna and Venice. He spent his last three years in France, where he died in 1519.
+
+Although he had no formal academic training,[9] many historians and scholars regard Leonardo as the prime exemplar of the "Universal Genius" or "Renaissance Man", an individual of "unquenchable curiosity" and "feverishly inventive imagination."[6] He is widely considered one of the most diversely talented individuals ever to have lived.[10] According to art historian Helen Gardner, the scope and depth of his interests were without precedent in recorded history, and "his mind and personality seem to us superhuman, while the man himself mysterious and remote."[6] Scholars interpret his view of the world as being based in logic, though the empirical methods he used were unorthodox for his time.[11]
+
+Leonardo is revered for his technological ingenuity. He conceptualized flying machines, a type of armoured fighting vehicle, concentrated solar power, an adding machine,[12] and the double hull. Relatively few of his designs were constructed or even feasible during his lifetime, as the modern scientific approaches to metallurgy and engineering were only in their infancy during the Renaissance. Some of his smaller inventions, however, entered the world of manufacturing unheralded, such as an automated bobbin winder and a machine for testing the tensile strength of wire. He is also sometimes credited with the inventions of the parachute, helicopter, and tank.[13][14] He made substantial discoveries in anatomy, civil engineering, geology, optics, and hydrodynamics, but he did not publish his findings and they had little to no direct influence on subsequent science.[15]
+
+Leonardo was born on 14/15 April 1452[b] in the Tuscan hill town of Vinci, in the lower valley of the Arno river in the territory of the Medici-ruled Republic of Florence.[18] He was the out-of-wedlock son of Messer Piero Fruosino di Antonio da Vinci, a wealthy Florentine legal notary, and a peasant named Caterina,[e] identified as Caterina Buti del Vacca and more recently as Caterina di Meo Lippi by historian Martin Kemp. There have been many theories regarding Leonardo's mother's identity, including that she was a slave of foreign origin or an impoverished local youth.[17][20][21][22][f] Leonardo had no surname in the modern sense—da Vinci simply meaning "of Vinci"; his full birth name was Lionardo di ser Piero da Vinci,[2][25] meaning "Leonardo, (son) of ser Piero (from) Vinci."[18][d]
+
+Leonardo spent his first years in the hamlet of Anchiano in the home of his mother, and from at least 1457 lived in the household of his father, grandparents and uncle in the small town of Vinci.[26] His father had married a 16-year-old girl named Albiera Amadori, who loved Leonardo but died young[27] in 1465 without children. In 1468, when Leonardo was 16, his father married again to 20-year-old Francesca Lanfredini, who also died without children. Piero's legitimate heirs were born from his third wife Margherita di Guglielmo, who gave birth to six children, and his fourth and final wife, Lucrezia Cortigiani, who bore him another six heirs.[28][29]
+In all, Leonardo had 12 half-siblings, who were much younger than he was (the last was born when Leonardo was 40 years old) and with whom he had very little contact.[g]
+
+Leonardo received an informal education in Latin, geometry and mathematics. In later life, Leonardo recorded few distinct childhood incidents. One was of a kite coming to his cradle and opening his mouth with its tail; he regarded this as an omen of his writing on the subject.[31][32] The second occurred while he was exploring in the mountains: he discovered a cave and was both terrified that some great monster might lurk there and driven by curiosity to find out what was inside.[27] He also seems to have remembered some of his childhood observations of water, writing and crossing out the name of his hometown in one of his notebooks on the formation of rivers.[26]
+
+Leonardo's early life has been the subject of historical conjecture.[33] Vasari, the 16th-century biographer of Renaissance painters, tells a story of Leonardo as a very young man: A local peasant made himself a round shield and requested that Ser Piero have it painted for him. Leonardo, inspired by the story of Medusa, responded with a painting of a monster spitting fire that was so terrifying that his father bought a different shield to give to the peasant and sold Leonardo's to a Florentine art dealer for 100 ducats, who in turn sold it to the Duke of Milan.[34]
+
+In the mid-1460s, Leonardo's family moved to Florence, and around the age of 14,[30] he became a garzone (studio boy) in the workshop of Verrocchio, who was the leading Florentine painter and sculptor of his time.[35] Leonardo became an apprentice by the age of 17 and remained in training for seven years.[36][37] Other famous painters apprenticed in the workshop or associated with it include Ghirlandaio, Perugino, Botticelli, and Lorenzo di Credi.[27][38] Leonardo was exposed to both theoretical training and a wide range of technical skills,[39] including drafting, chemistry, metallurgy, metal working, plaster casting, leather working, mechanics, and wood-work, as well as the artistic skills of drawing, painting, sculpting, and modelling.[40][h]
+
+Much of the painting in Verrocchio's workshop was done by his employees. According to Vasari, Leonardo collaborated with Verrocchio on his The Baptism of Christ, painting the young angel holding Jesus' robe in a manner that was so far superior to his master's that Verrocchio put down his brush and never painted again, although this is believed to be an apocryphal story.[41] Close examination reveals areas of the work that have been painted or touched-up over the tempera, using the new technique of oil paint, including the landscape, the rocks seen through the brown mountain stream, and much of the figure of Jesus, bearing witness to the hand of Leonardo.[42] Leonardo may have been the model for two works by Verrocchio: the bronze statue of David in the Bargello, and the Archangel Raphael in Tobias and the Angel.[20]
+
+By 1472, at the age of 20, Leonardo qualified as a master in the Guild of Saint Luke, the guild of artists and doctors of medicine,[i] but even after his father set him up in his own workshop, his attachment to Verrocchio was such that he continued to collaborate and live with him.[27][43] Leonardo's earliest known dated work is a 1473 pen-and-ink drawing of the Arno valley,[38] which has been cited as the first "pure" landscape in the Occident.[j][44] According to Vasari, the young Leonardo was the first to suggest making the Arno river a navigable channel between Florence and Pisa.[45]
+
+In January 1478, Leonardo received an independent commission to paint an altarpiece for the Chapel of St. Bernard in the Palazzo Vecchio,[46] an indication of his independence from Verrocchio's studio. One anonymous writer claims that in 1480, Leonardo was living with the Medici and often worked in the garden of the Piazza San Marco, Florence, where a Neoplatonic academy of artists, poets and philosophers organized by the Medici met.[20] In March 1481, he received a commission from the monks of San Donato in Scopeto for The Adoration of the Magi.[47]
+Neither of these initial commissions were completed, being abandoned when Leonardo went to offer his services to Duke of Milan Ludovico Sforza. In 1482, he casted a silver stringed instrument[k] from a horse's skull and ram horns to bring to Sforza,[48] whom he wrote a letter describing the diverse things that he could achieve in the fields of engineering and weapon design, and mentioning that he could paint.[38][48][49]
+
+Leonardo worked in Milan from 1482 until 1499. He was commissioned to paint the Virgin of the Rocks for the Confraternity of the Immaculate Conception and The Last Supper for the monastery of Santa Maria delle Grazie.[51] In the spring of 1485, Leonardo travelled to Hungary on behalf of Sforza to meet king Matthias Corvinus, and was commissioned by him to paint a Madonna.[52]
+Leonardo was employed on many other projects for Sforza, including the preparation of floats and pageants for special occasions, a drawing and wooden model for a competition to design the cupola for Milan Cathedral (which he withdrew),[53] and a model for a huge equestrian monument to Ludovico's predecessor Francesco Sforza. This would have surpassed in size the only two large equestrian statues of the Renaissance, Donatello's Gattamelata in Padua and Verrocchio's Bartolomeo Colleoni in Venice, and became known as the Gran Cavallo.[38] Leonardo completed a model for the horse and made detailed plans for its casting,[38] but in November 1494, Ludovico gave the bronze to his brother-in-law to be used for a cannon to defend the city from Charles VIII.[38]
+
+With Ludovico Sforza overthrown at the dawn of the Second Italian War, Leonardo, with his assistant Salaì and friend, the mathematician Luca Pacioli, fled Milan for Venice.[54] There, he was employed as a military architect and engineer, devising methods to defend the city from naval attack.[27] On his return to Florence in 1500, he and his household were guests of the Servite monks at the monastery of Santissima Annunziata and were provided with a workshop where, according to Vasari, Leonardo created the cartoon of The Virgin and Child with St Anne and St John the Baptist, a work that won such admiration that "men and women, young and old" flocked to see it "as if they were attending a great festival."[55][l]
+
+In Cesena in 1502, Leonardo entered the service of Cesare Borgia, the son of Pope Alexander VI, acting as a military architect and engineer and travelling throughout Italy with his patron.[54] Leonardo created a map of Cesare Borgia's stronghold, a town plan of Imola in order to win his patronage. Maps were extremely rare at the time and it would have seemed like a new concept. Upon seeing it, Cesare hired Leonardo as his chief military engineer and architect. Later in the year, Leonardo produced another map for his patron, one of Chiana Valley, Tuscany, so as to give his patron a better overlay of the land and greater strategic position. He created this map in conjunction with his other project of constructing a dam from the sea to Florence, in order to allow a supply of water to sustain the canal during all seasons.
+
+Leonardo had left Borgia's service and returned to Florence by early 1503,[57] where he rejoined the Guild of Saint Luke on 18 October of that year. By this same month, Leonardo had begun working on a portrait of Lisa del Giocondo, the model for the Mona Lisa,[58][59] which he would continue working on until his twilight years. In January 1504, he was part of a committee formed to recommend where Michelangelo's statue of David should be placed.[60] He then spent two years in Florence designing and painting a mural of The Battle of Anghiari for the Signoria,[54] with Michelangelo designing its companion piece, The Battle of Cascina.[m]
+
+In 1506, Leonardo was summoned to Milan by Charles II d'Amboise, the acting French governor of the city. The Council of Florence wished Leonardo to return promptly to finish The Battle of Anghiari, but he was given leave at the behest of Louis XII, who considered commissioning the artist to make some portraits.[63] Leonardo may have commenced a project for an equestrian figure of d'Amboise;[64] a wax model survives and, if genuine, is the only extant example of Leonardo's sculpture. Leonardo was otherwise free to pursue his scientific interests.[63] Many of Leonardo's most prominent pupils either knew or worked with him in Milan,[27] including Bernardino Luini, Giovanni Antonio Boltraffio, and Marco d'Oggiono.
+In 1507, Leonardo was in Florence sorting out a dispute with his brothers over the estate of his father, who had died in 1504. By 1508, Leonardo was back in Milan, living in his own house in Porta Orientale in the parish of Santa Babila.[65]
+
+In 1512, Leonardo was working on plans for an equestrian monument for Gian Giacomo Trivulzio, but this was prevented by an invasion of a confederation of Swiss, Spanish and Venetian forces, which drove the French from Milan. Leonardo stayed in the city, spending several months in 1513 at the Medici's Vaprio d'Adda villa.[67] In March of that year, Lorenzo de' Medici's son Giovanni assumed the papacy (as Leo X); Leonardo went to Rome that September, where he was received by the pope's brother Giuliano.[67] From September 1513 to 1516, Leonardo spent much of his time living in the Belvedere Courtyard in the Apostolic Palace, where Michelangelo and Raphael were both active.[65] Leonardo was given an allowance of 33 ducats a month, and according to Vasari, decorated a lizard with scales dipped in quicksilver.[68] The pope gave him a painting commission of unknown subject matter, but cancelled it when the artist set about developing a new kind of varnish.[68][n] Leonardo became ill, in what may have been the first of multiple strokes leading to his death.[68] He practiced botany in the Gardens of Vatican City, and was commissioned to make plans for the pope's proposed draining of the Pontine Marshes.[69] He also dissected cadavers, making notes for a treatise on vocal cords;[70] these he gave to an official in hopes of regaining the pope's favor, but was unsuccessful.[68]
+
+In October 1515, King Francis I of France recaptured Milan.[47] Leonardo was present at the 19 December meeting of Francis I and Leo X, which took place in Bologna.[27][71][72] In 1516, Leonardo entered Francis' service, being given the use of the manor house Clos Lucé, near the king's residence at the royal Château d'Amboise. Being frequently visited by Francis, he drew plans for an immense castle town the king intended to erect at Romorantin, and made a mechanical lion, which during a pageant walked toward the king and—upon being struck by a wand—opened its chest to reveal a cluster of lilies.[73][74][o] Leonardo was accompanied during this time by his friend and apprentice, Francesco Melzi, and supported by a pension totalling 10,000 scudi.[65] At some point, Melzi drew a portrait of Leonardo; the only others known from his lifetime were a sketch by an unknown assistant on the back of one of Leonardo's studies (c. 1517)[76] and a drawing by Giovanni Ambrogio Figino depicting an elderly Leonardo with his right arm assuaged by cloth.[77][p][q] The latter, in addition to the record of an October 1517 visit by Louis d'Aragon,[r] confirms an account of Leonardo's right hand being paralytic at the age of 65,[80] which may indicate why he left works such as the Mona Lisa unfinished.[78][81][82] He continued to work at some capacity until eventually becoming ill and bedridden for several months.[80]
+
+Leonardo died at Clos Lucé on 2 May 1519 at the age of 67, possibly of a stroke.[83][82] Francis I had become a close friend. Vasari describes Leonardo as lamenting on his deathbed, full of repentance, that "he had offended against God and men by failing to practice his art as he should have done."[84] Vasari states that in his last days, Leonardo sent for a priest to make his confession and to receive the Holy Sacrament.[85] Vasari also records that the king held Leonardo's head in his arms as he died, although this story may be legend rather than fact.[s][t] In accordance with his will, sixty beggars carrying tapers followed Leonardo's casket.[87][u] Melzi was the principal heir and executor, receiving, as well as money, Leonardo's paintings, tools, library and personal effects. Leonardo also remembered his other long-time pupil and companion, Salaì, and his servant Baptista de Vilanis, who each received half of Leonardo's vineyards.[88] His brothers received land, and his serving woman received a fur-lined cloak. On 12 August 1519, Leonardo's remains were interred in the Collegiate Church of Saint Florentin at the Château d'Amboise.[89]
+
+Some 20 years after Leonardo's death, Francis was reported by the goldsmith and sculptor Benvenuto Cellini as saying: "There had never been another man born in the world who knew as much as Leonardo, not so much about painting, sculpture and architecture, as that he was a very great philosopher."[90]
+
+Florence at the time of Leonardo's youth was the centre of Christian Humanist thought and culture.[35] Leonardo commenced his apprenticeship with Verrocchio in 1466, the year that Verrocchio's master, the great sculptor Donatello, died.[v] The painter Uccello, whose early experiments with perspective were to influence the development of landscape painting, was a very old man. The painters Piero della Francesca and Filippo Lippi, sculptor Luca della Robbia, and architect and writer Leon Battista Alberti were in their sixties. The successful artists of the next generation were Leonardo's teacher Verrocchio, Antonio del Pollaiuolo, and the portrait sculptor Mino da Fiesole.[91][92][93][94]
+
+Leonardo's youth was spent in a Florence that was ornamented by the works of these artists and by Donatello's contemporaries, Masaccio, whose figurative frescoes were imbued with realism and emotion; and Ghiberti, whose Gates of Paradise, gleaming with gold leaf, displayed the art of combining complex figure compositions with detailed architectural backgrounds. Piero della Francesca had made a detailed study of perspective,[95] and was the first painter to make a scientific study of light. These studies and Alberti's treatise De pictura[96] were to have a profound effect on younger artists and in particular on Leonardo's own observations and artworks.[91][93][94]
+
+A prevalent tradition in Florence was the small altarpiece of the Virgin and Child. Many of these were created in tempera or glazed terracotta by the workshops of Filippo Lippi, Verrocchio and the prolific della Robbia family.[91] Leonardo's early Madonnas such as The Madonna with a carnation and the Benois Madonna followed this tradition while showing idiosyncratic departures, particularly in the latter in which the Virgin is set at an oblique angle to the picture space with the Christ Child at the opposite angle. This compositional theme was to emerge in Leonardo's later paintings such as The Virgin and Child with St. Anne.[27]
+
+Leonardo was a contemporary of Botticelli, Domenico Ghirlandaio and Perugino, who were all slightly older than he was.[92] He would have met them at the workshop of Verrocchio, with whom they had associations, and at the Academy of the Medici.[27] Botticelli was a particular favourite of the Medici family, and thus his success as a painter was assured. Ghirlandaio and Perugino were both prolific and ran large workshops. They competently delivered commissions to well-satisfied patrons who appreciated Ghirlandaio's ability to portray the wealthy citizens of Florence within large religious frescoes, and Perugino's ability to deliver a multitude of saints and angels of unfailing sweetness and innocence.[91]
+These three were among those commissioned to paint the walls of the Sistine Chapel, the work commencing with Perugino's employment in 1479. Leonardo was not part of this prestigious commission. His first significant commission, The Adoration of the Magi for the Monks of Scopeto, was never completed.[27]
+
+In 1476, during the time of Leonardo's association with Verrocchio's workshop, the Portinari Altarpiece by Hugo van der Goes arrived in Florence, bringing from Northern Europe new painterly techniques that were to profoundly affect Leonardo, Ghirlandaio, Perugino and others.[92] In 1479, the Sicilian painter Antonello da Messina, who worked exclusively in oils, travelled north on his way to Venice, where the leading painter Giovanni Bellini adopted the technique of oil painting, quickly making it the preferred method in Venice. Leonardo was also later to visit Venice.[92][94]
+
+Like the two contemporary architects Donato Bramante (who designed the Belvedere Courtyard) and Antonio da Sangallo the Elder, Leonardo experimented with designs for centrally planned churches, a number of which appear in his journals, as both plans and views, although none was ever realised.[92][97]
+
+Leonardo's political contemporaries were Lorenzo de' Medici (il Magnifico), who was three years older, and his younger brother Giuliano, who was slain in the Pazzi conspiracy in 1478. Leonardo was sent as an ambassador by the Medici court to Ludovico il Moro, who ruled Milan between 1479 and 1499.[92]
+
+With Alberti, Leonardo visited the home of the Medici and through them came to know the older Humanist philosophers of whom Marsiglio Ficino, proponent of Neo Platonism; Cristoforo Landino, writer of commentaries on Classical writings, and John Argyropoulos, teacher of Greek and translator of Aristotle were the foremost. Also associated with the Academy of the Medici was Leonardo's contemporary, the brilliant young poet and philosopher Pico della Mirandola.[92][94][87] Leonardo later wrote in the margin of a journal, "The Medici made me and the Medici destroyed me." While it was through the action of Lorenzo that Leonardo received his employment at the court of Milan, it is not known exactly what Leonardo meant by this cryptic comment.[27]
+
+Although usually named together as the three giants of the High Renaissance, Leonardo, Michelangelo and Raphael were not of the same generation. Leonardo was 23 when Michelangelo was born and 31 when Raphael was born.[92] Raphael died at the age of 37 in 1520, the year after Leonardo died, but Michelangelo went on creating for another 45 years.[93][94]
+
+Within Leonardo's lifetime, his extraordinary powers of invention, his "outstanding physical beauty," "infinite grace," "great strength and generosity," "regal spirit and tremendous breadth of mind," as described by Vasari,[98] as well as all other aspects of his life, attracted the curiosity of others. One such aspect was his love for animals, likely including vegetarianism and according to Vasari, a habit of purchasing caged birds and releasing them.[99][100]
+
+Leonardo had many friends who are now renowned either in their fields or for their historical significance. They included the mathematician Luca Pacioli,[101] with whom he collaborated on the book Divina proportione in the 1490s. Leonardo appears to have had no close relationships with women except for his friendship with Cecilia Gallerani and the two Este sisters, Beatrice and Isabella.[102] While on a journey that took him through Mantua, he drew a portrait of Isabella that appears to have been used to create a painted portrait, now lost.[27]
+
+Beyond friendship, Leonardo kept his private life secret. His sexuality has been the subject of satire, analysis, and speculation. This trend began in the mid-16th century and was revived in the 19th and 20th centuries, most notably by Sigmund Freud.[103] Leonardo's most intimate relationships were perhaps with his pupils Salaì and Melzi. Melzi, writing to inform Leonardo's brothers of his death, described Leonardo's feelings for his pupils as both loving and passionate. It has been claimed since the 16th century that these relationships were of a sexual or erotic nature. Court records of 1476, when he was aged twenty-four, show that Leonardo and three other young men were charged with sodomy in an incident involving a well-known male prostitute. The charges were dismissed for lack of evidence, and there is speculation that since one of the accused, Lionardo de Tornabuoni, was related to Lorenzo de' Medici, the family exerted its influence to secure the dismissal.[104] Since that date much has been written about his presumed homosexuality and its role in his art, particularly in the androgyny and eroticism manifested in Saint John the Baptist and Bacchus and more explicitly in a number of erotic drawings.[105]
+
+Gian Giacomo Caprotti da Oreno, nicknamed Salaì or Il Salaino ("The Little Unclean One," i.e., the devil), entered Leonardo's household in 1490. After only a year, Leonardo made a list of his misdemeanours, calling him "a thief, a liar, stubborn, and a glutton," after he had made off with money and valuables on at least five occasions and spent a fortune on clothes.[106] Nevertheless, Leonardo treated him with great indulgence, and he remained in Leonardo's household for the next thirty years.[107] Salaì executed a number of paintings under the name of Andrea Salaì, but although Vasari claims that Leonardo "taught him a great deal about painting,"[74] his work is generally considered to be of less artistic merit than others among Leonardo's pupils, such as Marco d'Oggiono and Boltraffio. In 1515, he painted a nude version of the Mona Lisa, known as Monna Vanna.[108] Salaì owned the Mona Lisa at the time of his death in 1524, and in his will it was assessed at 505 lire, an exceptionally high valuation for a small panel portrait.[109]
+
+In 1506, Leonardo took on another pupil, Count Francesco Melzi, the son of a Lombard aristocrat, who is considered to have been his favourite student. He travelled to France with Leonardo and remained with him until Leonardo's death.[27] Melzi inherited the artistic and scientific works, manuscripts, and collections of Leonardo and administered the estate.
+
+Despite the recent awareness and admiration of Leonardo as a scientist and inventor, for the better part of four hundred years his fame rested on his achievements as a painter. A handful of works that are either authenticated or attributed to him have been regarded as among the great masterpieces. These paintings are famous for a variety of qualities that have been much imitated by students and discussed at great length by connoisseurs and critics. By the 1490s Leonardo had already been described as a "Divine" painter.[110]
+
+Among the qualities that make Leonardo's work unique are his innovative techniques for laying on the paint; his detailed knowledge of anatomy, light, botany and geology; his interest in physiognomy and the way humans register emotion in expression and gesture; his innovative use of the human form in figurative composition; and his use of subtle gradation of tone. All these qualities come together in his most famous painted works, the Mona Lisa, the Last Supper, and the Virgin of the Rocks.[111]
+
+Leonardo first gained attention for his work on the Baptism of Christ, painted in conjunction with Verrocchio. Two other paintings appear to date from his time at Verrocchio's workshop, both of which are Annunciations. One is small, 59 centimetres (23 in) long and 14 centimetres (5.5 in) high. It is a "predella" to go at the base of a larger composition, a painting by Lorenzo di Credi from which it has become separated. The other is a much larger work, 217 centimetres (85 in) long.[112] In both Annunciations, Leonardo used a formal arrangement, like two well-known pictures by Fra Angelico of the same subject, of the Virgin Mary sitting or kneeling to the right of the picture, approached from the left by an angel in profile, with a rich flowing garment, raised wings and bearing a lily. Although previously attributed to Ghirlandaio, the larger work is now generally attributed to Leonardo.[113]
+
+In the smaller painting, Mary averts her eyes and folds her hands in a gesture that symbolised submission to God's will. Mary is not submissive, however, in the larger piece. The girl, interrupted in her reading by this unexpected messenger, puts a finger in her bible to mark the place and raises her hand in a formal gesture of greeting or surprise.[91] This calm young woman appears to accept her role as the Mother of God, not with resignation but with confidence. In this painting, the young Leonardo presents the humanist face of the Virgin Mary, recognising humanity's role in God's incarnation.
+
+In the 1480s, Leonardo received two very important commissions and commenced another work that was of ground-breaking importance in terms of composition. Two of the three were never finished, and the third took so long that it was subject to lengthy negotiations over completion and payment.
+
+One of these paintings was Saint Jerome in the Wilderness, which Bortolon associates with a difficult period of Leonardo's life, as evidenced in his diary: "I thought I was learning to live; I was only learning to die."[27] Although the painting is barely begun, the composition can be seen and is very unusual.[w] Jerome, as a penitent, occupies the middle of the picture, set on a slight diagonal and viewed somewhat from above. His kneeling form takes on a trapezoid shape, with one arm stretched to the outer edge of the painting and his gaze looking in the opposite direction. J. Wasserman points out the link between this painting and Leonardo's anatomical studies.[114] Across the foreground sprawls his symbol, a great lion whose body and tail make a double spiral across the base of the picture space. The other remarkable feature is the sketchy landscape of craggy rocks against which the figure is silhouetted.
+
+The daring display of figure composition, the landscape elements and personal drama also appear in the great unfinished masterpiece, the Adoration of the Magi, a commission from the Monks of San Donato a Scopeto. It is a complex composition, of about 250 x 250 centimetres. Leonardo did numerous drawings and preparatory studies, including a detailed one in linear perspective of the ruined classical architecture that forms part of the background. In 1482 Leonardo went to Milan at the behest of Lorenzo de' Medici in order to win favour with Ludovico il Moro, and the painting was abandoned.[20][113]
+
+The third important work of this period is the Virgin of the Rocks, commissioned in Milan for the Confraternity of the Immaculate Conception. The painting, to be done with the assistance of the de Predis brothers, was to fill a large complex altarpiece.[115] Leonardo chose to paint an apocryphal moment of the infancy of Christ when the infant John the Baptist, in protection of an angel, met the Holy Family on the road to Egypt. The painting demonstrates an eerie beauty as the graceful figures kneel in adoration around the infant Christ in a wild landscape of tumbling rock and whirling water.[116] While the painting is quite large, about 200×120 centimetres, it is not nearly as complex as the painting ordered by the monks of St Donato, having only four figures rather than about fifty and a rocky landscape rather than architectural details. The painting was eventually finished; in fact, two versions of the painting were finished: one remained at the chapel of the Confraternity, while Leonardo took the other to France. The Brothers did not get their painting, however, nor the de Predis their payment, until the next century.[38][54]
+
+Leonardo's most remarkable portrait of this period is the Lady with an Ermine, presumed to be  Cecilia Gallerani (c. 1483–1490), lover of Ludovico Sforza.[117][118] The painting is charcterised by the pose of the figure with the head turned at a very different angle to the torso, unusual at a date when many portraits were still rigidly in profile. The ermine plainly carries symbolic meaning, relating either to the sitter, or to Ludovico who belonged to the prestigious Order of the Ermine.[117]
+
+Leonardo's most famous painting of the 1490s is The Last Supper, commissioned for the refectory of the Convent of Santa Maria della Grazie in Milan. It represents the last meal shared by Jesus with his disciples before his capture and death, and shows the moment when Jesus has just said "one of you will betray me", and the consternation that this statement caused.[38]
+
+The novelist Matteo Bandello observed Leonardo at work and wrote that some days he would paint from dawn till dusk without stopping to eat and then not paint for three or four days at a time.[119] This was beyond the comprehension of the prior of the convent, who hounded him until Leonardo asked Ludovico to intervene. Vasari describes how Leonardo, troubled over his ability to adequately depict the faces of Christ and the traitor Judas, told the Duke that he might be obliged to use the prior as his model.[120]
+
+When finished, the painting was acclaimed as a masterpiece of design and characterization,[121] but it deteriorated rapidly, so that within a hundred years it was described by one viewer as "completely ruined."[122] Leonardo, instead of using the reliable technique of fresco, had used tempera over a ground that was mainly gesso, resulting in a surface subject to mould and to flaking.[123] Despite this, the painting remains one of the most reproduced works of art; countless copies have been made in various mediums.
+
+It is recorded that in 1492, Leonardo, with assistants painted the Sala delle Asse in the Sforza Castle in Milan,  with a trompe-l'œil depicting trees, with an intricate labyrinth of leaves and knots on the ceiling.[124]
+
+In 1505 Leonardo was commissioned to paint The Battle of Anghiari in the Salone dei Cinquecento (Hall of the Five Hundred) in the Palazzo Vecchio, Florence. Leonardo devised a dynamic composition depicting four men riding raging war horses engaged in a battle for possession of a standard, at the Battle of Anghiari in 1440.  Michelangelo was assigned the opposite wall to depict the Battle of Cascina. Leonardo's painting deteriorated rapidly and is now known from a copy by Rubens.[125]
+
+Among the works created by Leonardo in the 16th century is the small portrait known as the Mona Lisa or La Gioconda, the laughing one. In the present era, it is arguably the most famous painting in the world. Its fame rests, in particular, on the elusive smile on the woman's face, its mysterious quality perhaps due to the subtly shadowed corners of the mouth and eyes such that the exact nature of the smile cannot be determined. The shadowy quality for which the work is renowned came to be called "sfumato," or Leonardo's smoke. Vasari, who is generally thought to have known the painting only by repute, said that "the smile was so pleasing that it seemed divine rather than human; and those who saw it were amazed to find that it was as alive as the original."[126][x]
+
+Other characteristics of the painting are the unadorned dress, in which the eyes and hands have no competition from other details; the dramatic landscape background, in which the world seems to be in a state of flux; the subdued colouring; and the extremely smooth nature of the painterly technique, employing oils laid on much like tempera, and blended on the surface so that the brushstrokes are indistinguishable.[y] Vasari expressed the opinion that the manner of painting would make even "the most confident master...despair and lose heart."[129] The perfect state of preservation and the fact that there is no sign of repair or overpainting is rare in a panel painting of this date.[130]
+
+In the painting Virgin and Child with St. Anne, the composition again picks up the theme of figures in a landscape, which Wasserman describes as "breathtakingly beautiful"[131] and harkens back to the St Jerome picture with the figure set at an oblique angle. What makes this painting unusual is that there are two obliquely set figures superimposed. Mary is seated on the knee of her mother, St Anne. She leans forward to restrain the Christ Child as he plays roughly with a lamb, the sign of his own impending sacrifice.[38] This painting, which was copied many times, influenced Michelangelo, Raphael, and Andrea del Sarto,[132] and through them Pontormo and Correggio. The trends in composition were adopted in particular by the Venetian painters Tintoretto and Veronese.
+
+Leonardo was not a prolific painter, but he was a most prolific draftsman, keeping journals full of small sketches and detailed drawings recording all manner of things that took his attention. As well as the journals there exist many studies for paintings, some of which can be identified as preparatory to particular works such as The Adoration of the Magi, The Virgin of the Rocks and The Last Supper.[133]
+His earliest dated drawing is a Landscape of the Arno Valley, 1473, which shows the river, the mountains, Montelupo Castle and the farmlands beyond it in great detail.[27][133][z] According to art historian Ludwig Heydenreich, this is "The first true landscape in art."[134] Massimo Polidoro says that it was the first landscape "not to be the background of some religious scene or a portrait. It is the first [documented] time where a landscape was drawn just for the sake of it."[44]
+
+Among his famous drawings are the Vitruvian Man, a study of the proportions of the human body; the Head of an Angel, for The Virgin of the Rocks in the Louvre; a botanical study of Star of Bethlehem; and a large drawing (160×100 cm) in black chalk on coloured paper of The Virgin and Child with St. Anne and St. John the Baptist in the National Gallery, London.[133] This drawing employs the subtle sfumato technique of shading, in the manner of the Mona Lisa. It is thought that Leonardo never made a painting from it, the closest similarity being to The Virgin and Child with St. Anne in the Louvre.[135]
+
+Other drawings of interest include numerous studies generally referred to as "caricatures" because, although exaggerated, they appear to be based upon observation of live models. Vasari relates that if Leonardo saw a person with an interesting face he would follow them around all day observing them.[136] There are numerous studies of beautiful young men, often associated with Salaì, with the rare and much admired facial feature, the so-called "Grecian profile."[aa] These faces are often contrasted with that of a warrior.[133] Salaì is often depicted in fancy-dress costume. Leonardo is known to have designed sets for pageants with which these may be associated. Other, often meticulous, drawings show studies of drapery. A marked development in Leonardo's ability to draw drapery occurred in his early works. Another often-reproduced drawing is a macabre sketch that was done by Leonardo in Florence in 1479 showing the body of Bernardo Baroncelli, hanged in connection with the murder of Giuliano, brother of Lorenzo de' Medici, in the Pazzi conspiracy.[133] In his notes, Leonardo recorded the colours of the robes that Baroncelli was wearing when he died.
+
+Renaissance humanism recognised no mutually exclusive polarities between the sciences and the arts, and Leonardo's studies in science and engineering are sometimes considered as impressive and innovative as his artistic work.[38] These studies were recorded in 13,000 pages of notes and drawings, which fuse art and natural philosophy (the forerunner of modern science). They were made and maintained daily throughout Leonardo's life and travels, as he made continual observations of the world around him.[38]
+Leonardo's notes and drawings display an enormous range of interests and preoccupations, some as mundane as lists of groceries and people who owed him money and some as intriguing as designs for wings and shoes for walking on water. There are compositions for paintings, studies of details and drapery, studies of faces and emotions, of animals, babies, dissections, plant studies, rock formations, whirlpools, war machines, flying machines and architecture.[38]
+
+These notebooks—originally loose papers of different types and sizes, were largely entrusted to Leonardo's pupil and heir Francesco Melzi after the master's death.[137] These were to be published, a task of overwhelming difficulty because of its scope and Leonardo's idiosyncratic writing.[138] Some of Leonardo's drawings were copied by an anonymous Milanese artist for a planned treatise on art c. 1570.[139] After Melzi's death in 1570, the collection passed to his son, the lawyer Orazio, who initially took little interest in the journals.[137] In 1587, a Melzi household tutor named Lelio Gavardi took 13 of the manuscripts to Pisa; there, the architect Giovanni Magenta reproached Gavardi for having taken the manuscripts illicitly and returned them to Orazio. Having many more such works in his possession, Orazio gifted the volumes to Magenta. News spread of these lost works of Leonardo's, and Orazio retrieved seven of the 13 manuscripts, which he then gave to Pompeo Leoni for publication in two volumes; one of these was the Codex Atlanticus. The other six works had been distributed to a few others.[140] After Orazio's death, his heirs sold the rest of Leonardo's possessions, and thus began their dispersal.[141]
+
+Some works have found their way into major collections such as the Royal Library at Windsor Castle, the Louvre, the Biblioteca Nacional de España, the Victoria and Albert Museum, the Biblioteca Ambrosiana in Milan, which holds the 12-volume Codex Atlanticus, and the British Library in London, which has put a selection from the Codex Arundel (BL Arundel MS 263) online.[142] Works have also been at Holkham Hall, the Metropolitan Museum of Art, and in the private hands of John Nicholas Brown I and Robert Lehman.[137] The Codex Leicester is the only privately owned major scientific work of Leonardo; it is owned by Bill Gates and displayed once a year in different cities around the world.
+
+Most of Leonardo's writings are in mirror-image cursive.[143][44] Since Leonardo wrote with his left hand, it was probably easier for him to write from right to left.[144][ab] Leonardo used a variety of shorthand and symbols, and states in his notes that he intended to prepare them for publication.[143] In many cases a single topic is covered in detail in both words and pictures on a single sheet, together conveying information that would not be lost if the pages were published out of order.[147] Why they were not published during Leonardo's lifetime is unknown.[38]
+
+Leonardo's approach to science was observational: he tried to understand a phenomenon by describing and depicting it in utmost detail and did not emphasise experiments or theoretical explanation. Since he lacked formal education in Latin and mathematics, contemporary scholars mostly ignored Leonardo the scientist, although he did teach himself Latin. In the 1490s he studied mathematics under Luca Pacioli and prepared a series of drawings of regular solids in a skeletal form to be engraved as plates for Pacioli's book Divina proportione, published in 1509.[38] While living in Milan, he studied light from the summit of Monte Rosa.[63] Scientific writings in his notebook on fossils have been considered as influential on early palaeontology[148][149] and he has been called the father of ichnology.[150]
+
+The content of his journals suggest that he was planning a series of treatises on a variety of subjects. A coherent treatise on anatomy is said to have been observed during a visit by Cardinal Louis d'Aragon's secretary in 1517.[151] Aspects of his work on the studies of anatomy, light and the landscape were assembled for publication by Melzi and eventually published as A Treatise on Painting in France and Italy in 1651 and Germany in 1724,[152] with engravings based upon drawings by the Classical painter Nicolas Poussin.[153] According to Arasse, the treatise, which in France went into 62 editions in fifty years, caused Leonardo to be seen as "the precursor of French academic thought on art."[38]
+
+While Leonardo's experimentation followed scientific methods, a recent and exhaustive analysis of Leonardo as a scientist by Fritjof Capra argues that Leonardo was a fundamentally different kind of scientist from Galileo, Newton and other scientists who followed him in that, as a "Renaissance Man", his theorising and hypothesising integrated the arts and particularly painting.[154][page needed]
+
+Leonardo started his study in the anatomy of the human body under the apprenticeship of Andrea del Verrocchio, who demanded that his students develop a deep knowledge of the subject.[155] As an artist, he quickly became master of topographic anatomy, drawing many studies of muscles, tendons and other visible anatomical features.
+
+As a successful artist, Leonardo was given permission to dissect human corpses at the Hospital of Santa Maria Nuova in Florence and later at hospitals in Milan and Rome. From 1510 to 1511 he collaborated in his studies with the doctor Marcantonio della Torre. Leonardo made over 240 detailed drawings and wrote about 13,000 words towards a treatise on anatomy.[156] Only a small amount of the material on anatomy was published in Leonardo's Treatise on painting.[138] During the time that Melzi was ordering the material into chapters for publication, they were examined by a number of anatomists and artists, including Vasari, Cellini and Albrecht Dürer, who made a number of drawings from them.[138]
+
+Leonardo's anatomical drawings include many studies of the human skeleton and its parts, and of muscles and sinews. He studied the mechanical functions of the skeleton and the muscular forces that are applied to it in a manner that prefigured the modern science of biomechanics.[157] He drew the heart and vascular system, the sex organs and other internal organs, making one of the first scientific drawings of a fetus in utero.[133] The drawings and notation are far ahead of their time, and if published would undoubtedly have made a major contribution to medical science.[156]
+
+Leonardo also closely observed and recorded the effects of age and of human emotion on the physiology, studying in particular the effects of rage. He drew many figures who had significant facial deformities or signs of illness.[38][133] Leonardo also studied and drew the anatomy of many animals, dissecting cows, birds, monkeys, bears, and frogs, and comparing in his drawings their anatomical structure with that of humans. He also made a number of studies of horses.[133]
+
+Leonardo's dissections and documentation of muscles, nerves, and vessels helped to describe the physiology and mechanics of movement. He attempted to identify the source of 'emotions' and their expression. He found it difficult to incorporate the prevailing system and theories of bodily humours, but eventually he abandoned these physiological explanations of bodily functions. He made the observations that humours were not located in cerebral spaces or ventricles. He documented that the humours were not contained in the heart or the liver, and that it was the heart that defined the circulatory system. He was the first to define atherosclerosis and liver cirrhosis. He created models of the cerebral ventricles with the use of melted wax and constructed a glass aorta to observe the circulation of blood through the aortic valve by using water and grass seed to watch flow patterns. Vesalius published his work on anatomy and physiology in De humani corporis fabrica in 1543.[158]
+
+During his lifetime, Leonardo was also valued as an engineer. With the same rational and analytical approach that moved him to represent the human body and to investigate anatomy, Leonardo studied and designed a bewildering number of machines and devices. He drew their “anatomy” with unparalleled mastery, producing the first form of the modern technical drawing, including a perfected "exploded view" technique, to represent internal components. Those studies and projects collected in his codices fill more than 5,000 pages.[159] In a letter of 1482 to the lord of Milan Ludovico il Moro, he wrote that he could create all sorts of machines both for the protection of a city and for siege. When he fled from Milan to Venice in 1499, he found employment as an engineer and devised a system of moveable barricades to protect the city from attack. In 1502, he created a scheme for diverting the flow of the Arno river, a project on which Niccolò Machiavelli also worked.[160][161] He continued to contemplate the canalization of Lombardy's plains while in Louis XII's company[63] and of the Loire and its tributaries in the company of Francis I.[162] Leonardo's journals include a vast number of inventions, both practical and impractical. They include musical instruments, a mechanical knight, hydraulic pumps, reversible crank mechanisms, finned mortar shells, and a steam cannon.[27][38]
+
+Leonardo was fascinated by the phenomenon of flight for much of his life, producing many studies, including Codex on the Flight of Birds (c. 1505), as well as plans for several flying machines, such as a flapping ornithopter and a machine with a helical rotor.[38] A 2003 documentary by British television station Channel Four, titled Leonardo's Dream Machines, various designs by Leonardo, such as a parachute and a giant crossbow, were interpreted and constructed.[163][164] Some of those designs proved successful, whilst others fared less well when tested.
+
+Research performed by Marc van den Broek revealed older prototypes for more than 100 inventions that are ascribed to Leonardo. Similarities between Leonardo´s illustrations and drawings from the Middle Ages and from Ancient Greece and Rome, the Chinese and Persian Empires, and Egypt suggest that a large portion of Leonardo's inventions had been conceived before his lifetime. Leonardo´s innovation was to combine different functions from existing drafts and set them into scenes that illustrated their utility. By reconstituting technical inventions he created something new.[165]
+
+Leonardo's fame within his own lifetime was such that the King of France carried him away like a trophy, and was claimed to have supported him in his old age and held him in his arms as he died. Interest in Leonardo and his work has never diminished. Crowds still queue to see his best-known artworks, T-shirts still bear his most famous drawing, and writers continue to hail him as a genius while speculating about his private life, as well as about what one so intelligent actually believed in.[38]
+
+The continued admiration that Leonardo commanded from painters, critics and historians is reflected in many other written tributes. Baldassare Castiglione, author of Il Cortegiano (The Courtier), wrote in 1528: "...Another of the greatest painters in this world looks down on this art in which he is unequalled..."[166] while the biographer known as "Anonimo Gaddiano" wrote, c. 1540: "His genius was so rare and universal that it can be said that nature worked a miracle on his behalf..."[167]
+
+Giorgio Vasari, in the enlarged edition of Lives of the Artists (1568)[168] introduced his chapter on Leonardo with the following words:
+
+In the normal course of events many men and women are born with remarkable talents; but occasionally, in a way that transcends nature, a single person is marvellously endowed by Heaven with beauty, grace and talent in such abundance that he leaves other men far behind, all his actions seem inspired and indeed everything he does clearly comes from God rather than from human skill. Everyone acknowledged that this was true of Leonardo da Vinci, an artist of outstanding physical beauty, who displayed infinite grace in everything that he did and who cultivated his genius so brilliantly that all problems he studied he solved with ease.
+
+The 19th century brought a particular admiration for Leonardo's genius, causing Henry Fuseli to write in 1801: "Such was the dawn of modern art, when Leonardo da Vinci broke forth with a splendour that distanced former excellence: made up of all the elements that constitute the essence of genius..."[169] This is echoed by A.E. Rio who wrote in 1861: "He towered above all other artists through the strength and the nobility of his talents."[170]
+
+By the 19th century, the scope of Leonardo's notebooks was known, as well as his paintings. Hippolyte Taine wrote in 1866: "There may not be in the world an example of another genius so universal, so incapable of fulfilment, so full of yearning for the infinite, so naturally refined, so far ahead of his own century and the following centuries."[171]
+Art historian Bernard Berenson wrote in 1896: "Leonardo is the one artist of whom it may be said with perfect literalness: Nothing that he touched but turned into a thing of eternal beauty. Whether it be the cross section of a skull, the structure of a weed, or a study of muscles, he, with his feeling for line and for light and shade, forever transmuted it into life-communicating values."[172]
+
+The interest in Leonardo's genius has continued unabated; experts study and translate his writings, analyse his paintings using scientific techniques, argue over attributions and search for works which have been recorded but never found.[173] Liana Bortolon, writing in 1967, said: "Because of the multiplicity of interests that spurred him to pursue every field of knowledge...Leonardo can be considered, quite rightly, to have been the universal genius par excellence, and with all the disquieting overtones inherent in that term. Man is as uncomfortable today, faced with a genius, as he was in the 16th century. Five centuries have passed, yet we still view Leonardo with awe."[27]
+
+Twenty-first-century author Walter Isaacson based much of his biography of Leonardo[104] on thousands of notebook entries, studying the personal notes, sketches, budget notations, and musings of the man whom he considers the greatest of innovators. Isaacson was surprised to discover a "fun, joyous" side of Leonardo in addition to his limitless curiosity and creative genius.[174]
+
+On the 500th anniversary of Leonardo's death, the Louvre in Paris arranged for the largest ever single exhibit of his work, called Leonardo, between November 2019 and February 2020. The exhibit includes over 100 paintings, drawings and notebooks. Eleven of the paintings that Leonardo completed in his lifetime were included. Five of these are owned by the Louvre, but the Mona Lisa was not included because it is in such great demand among general visitors to the Louvre; it remains on display in its gallery. Vitruvian Man, however, is on display following a legal battle with its owner, the Gallerie dell'Accademia in Venice. Salvator Mundi was also not included because its Saudi owner did not agree to lease the work.[175][176]
+
+Much of the Collegiate Church of Saint Florentin at the Château d'Amboise, where Leonardo was buried, was damaged during the French Revolution, leading to the church's demolition in 1802.[177] Some of the graves were destroyed in the process, scattering the bones interred there and thereby leaving the whereabouts of Leonardo's remains subject to dispute. While excavating the site in 1863, fine-arts inspector general Arsène Houssaye found a partially complete skeleton with a bronze ring on one finger, some white hair, and stone fragments bearing the inscriptions "EO," "AR," "DUS," and "VINC"—interpreted as forming "Leonardus Vinci".[177][89][178][179] A silver shield found near the bones depicts a beardless Francis I, corresponding to the king's appearance during Leonardo's lifetime, and the skull's inclusion of eight teeth corresponds to someone of approximately the appropriate age.[178] The unusually large skull led Houssaye to believe that he had located Leonardo's remains,[179] but he thought the skeleton seemed too short.[178] Other art historians say that the 1.73 metres (5.7 ft) tall skeleton may well be Leonardo's.[180]
+
+The remains, except for the ring and a lock of hair which Houssaye kept,[89] were brought to Paris in a lead box, where the skull was allegedly presented to Napoleon III,[178] before being returned to the Château d'Amboise and re-interred in the Chapel of Saint Hubert in 1874.[177] A new memorial tombstone was added by sculptor Francesco La Monaca in the 1930s.[181] Reflecting doubts about the attribution, a plaque above the tomb states that the remains are only presumed to be those of Leonardo.[177] It has since been theorized that the folding of the skeleton's right arm over the head may correspond to the paralysis of Leonardo's right hand.[178][77][83]
+In 2016, it was announced that DNA tests would be conducted to determine whether the attribution is correct.[177] The DNA of the remains will be compared to that of samples collected from Leonardo's work and his half-brother Domenico's descendants;[177] it may also be sequenced.[182] The lock of hair and ring, now in a private US collection,[ac] were displayed in Vinci beginning on 2 May 2019, the 500th anniversary of the artist's death.[183][89]
+
+Salvator Mundi, a painting by Leonardo depicting Jesus holding an orb, sold for a world record US$450.3 million at a Christie's auction in New York, 15 November 2017.[184] The highest known sale price for any artwork was previously US$300 million, for Willem de Kooning's Interchange, which was sold privately in September 2015.[185] The highest price previously paid for a work of art at auction was for Pablo Picasso's Les Femmes d'Alger, which sold for US$179.4 million in May 2015 at Christie's New York.[185]
+
+Early sources
+
+Modern sources
+

en/5996.html.txt

@@ -0,0 +1,158 @@
+Wine is an alcoholic drink typically made from fermented grapes. Yeast consumes the sugar in the grapes and converts it to ethanol, carbon dioxide, and heat. Different varieties of grapes and strains of yeasts produce different styles of wine. These variations result from the complex interactions between the biochemical development of the grape, the reactions involved in fermentation, the grape's growing environment (terroir), and the production process. Many countries enact legal appellations intended to define styles and qualities of wine. These typically restrict the geographical origin and permitted varieties of grapes, as well as other aspects of wine production. Wines not made from grapes involve fermentation of additional crops including,  rice wine and other fruit wines such as plum, cherry, pomegranate, currant and elderberry.
+
+Wine has been produced for thousands of years. The earliest evidence of wine is from Georgia, Iran (5000 BC), and Sicily (4000 BC). New World wine has some connection to alcoholic beverages made by the indigenous peoples of the Americas, but is mainly connected to later Viking area of Vinland and Spanish traditions in New Spain.[1][2] Later, as Old World wine further developed viticulture techniques, Europe would encompass three of the largest wine-producing regions. Today, the five countries with the largest wine-producing regions are in Italy, Spain, France, the United States, and China.[3]
+
+Wine has long played an important role in religion. Red wine was associated with blood by the ancient Egyptians[4] and was used by both the Greek cult of Dionysus and the Romans in their Bacchanalia; Judaism also incorporates it in the Kiddush and Christianity in the Eucharist. Egyptian, Greek, Roman, and Israeli wine cultures are still connected to these ancient roots. Similarly the largest wine regions in Italy, Spain, and France have heritages in connection to sacramental wine, likewise, viticulture traditions in the Southwestern United States started within New Spain as Catholic friars and monks first produced wines in New Mexico and California.[5][6][7]
+
+The earliest known traces of wine are from Georgia (c. 6000 BC),[8][9][10][11][12][13] Iran (Persia) (c. 5000 BC),[14][15] and Sicily (c. 4000 BC)[16]  although there is evidence of a similar alcoholic drink being consumed earlier in China (c. 7000 BC).[17][18][19] Wine reached the Balkans by 4500 BC and was consumed and celebrated in ancient Greece, Thrace and Rome. Throughout history, wine has been consumed for its intoxicating effects.[20][21][22].
+
+In 2017 the research led by Dr. Patrick E. McGovern, Scientific Director of the Biomolecular Archaeology Project for Cuisine, Fermented Beverages, and Health at the University of Pennsylvania Museum in Philadelphia acknowledged Georgia as the birthplace of wine. [23]
+
+The earliest archaeological and archaeobotanical evidence for grape wine and viniculture, dating to 6000–5800 BC was found on the territory of modern Georgia.[24][25] Both archaeological and genetic evidence suggest that the earliest production of wine elsewhere was relatively later, likely having taken place in the Southern Caucasus (which encompasses Armenia, Georgia and Azerbaijan), or the West Asian region between Eastern Turkey, and northern Iran.[26][27]
+
+The earliest evidence of a rice and grape mixed based fermented drink was found in China (c. 7000 BC),[17][18][19] earliest evidence of wine in Georgia from 6000 BC,[28][29][30] Iran from 5000 BC,[14] and Sicily from 4000 BC.[16]
+
+One of the earliest known wineries from 4100 BC is the Areni-1 winery in Armenia.[31][32]
+
+A 2003 report by archaeologists indicates a possibility that grapes were mixed with rice to produce mixed fermented drinks in China in the early years of the seventh millennium BC. Pottery jars from the Neolithic site of Jiahu, Henan, contained traces of tartaric acid and other organic compounds commonly found in wine. However, other fruits indigenous to the region, such as hawthorn, cannot be ruled out.[33][34] If these drinks, which seem to be the precursors of rice wine, included grapes rather than other fruits, they would have been any of the several dozen indigenous wild species in China, rather than Vitis vinifera, which was introduced there 6000 years later.[33]
+
+The spread of wine culture westwards was most probably due to the Phoenicians who spread outward from a base of city-states along the Mediterranean coast of what are today Lebanon, Israel, Syria, and Palestine.[35] The wines of Byblos were exported to Egypt during the Old Kingdom and then throughout the Mediterranean. Evidence includes two Phoenician shipwrecks from 750 BC discovered by Robert Ballard, whose cargo of wine was still intact.[36] As the first great traders in wine (cherem), the Phoenicians seem to have protected it from oxidation with a layer of olive oil, followed by a seal of pinewood and resin, similar to retsina. Although the Nuragic culture in Sardinia already had a custom of consuming wine before the arrival of the Phoenicians.[37][38]
+
+The earliest remains of Apadana Palace in Persepolis dating back to 515 BC include carvings depicting soldiers from Achaemenid Empire subject nations bringing gifts to the Achaemenid king, among them Armenians bringing their famous wine.
+
+Literary references to wine are abundant in Homer (8th century BC, but possibly relating earlier compositions), Alkman (7th century BC), and others. In ancient Egypt, six of 36 wine amphoras were found in the tomb of King Tutankhamun bearing the name "Kha'y", a royal chief vintner. Five of these amphoras were designated as originating from the king's personal estate, with the sixth from the estate of the royal house of Aten.[39] Traces of wine have also been found in central Asian Xinjiang in modern-day China, dating from the second and first millennia BC.[40]
+
+The first known mention of grape-based wines in India is from the late 4th-century BC writings of Chanakya, the chief minister of Emperor Chandragupta Maurya. In his writings, Chanakya condemns the use of alcohol while chronicling the emperor and his court's frequent indulgence of a style of wine known as madhu.[41]
+
+The ancient Romans planted vineyards near garrison towns so wine could be produced locally rather than shipped over long distances. Some of these areas are now world-renowned for wine production.[42] The Romans discovered that burning sulfur candles inside empty wine vessels kept them fresh and free from a vinegar smell.[43] In medieval Europe, the Roman Catholic Church supported wine because the clergy required it for the Mass. Monks in France made wine for years, aging it in caves.[44] An old English recipe that survived in various forms until the 19th century calls for refining white wine from bastard—bad or tainted bastardo wine.[45]
+
+Later, the descendants of the sacramental wine were refined for a more palatable taste. This gave rise to modern viticulture in French wine, Italian wine, Spanish wine, and these wine grape traditions were brought into New World wine. For example, Mission grapes were brought by Franciscan monks to New Mexico in 1628 beginning the New Mexico wine heritage, these grapes were also brought to California which started the California wine industry. Both of these regions eventually evolved into American wine's oldest and largest wine producers respectively. [46][47][48] Earlier Viking expeditions of Vinland recorded the first  grape vines found in the New World,[49] and prior to the Spanish establishing their American wine grape traditions in California and New Mexico, both France and Britain had unsuccessfully attempted to establish grapevines in Florida and Virginia respectively.[50]
+
+The English word "wine" comes from the Proto-Germanic *winam, an early borrowing from the Latin vinum, "wine" or "(grape) vine", itself derived from the Proto-Indo-European stem *win-o- (cf. Armenian: գինի, gini; Ancient Greek: οἶνος oinos; Aeolic Greek: ϝοῖνος woinos; Hittite: wiyana; Lycian: oino).[51][52][53] The earliest attested terms referring to wine are the Mycenaean Greek 𐀕𐀶𐀺𐄀𐀚𐀺 me-tu-wo ne-wo (*μέθυϝος νέϝῳ),[54][55] meaning "in (the month)" or "(festival) of the new wine", and 𐀺𐀜𐀷𐀴𐀯 wo-no-wa-ti-si,[56] meaning "wine garden", written in Linear B inscriptions.[57][58][59][60] Linear B also includes, inter alia, an ideogram for wine, i.e. 𐂖.
+
+The ultimate Indo-European origin of the word is the subject of continued debate. Some scholars have noted the similarities between the words for wine in Indo-European languages (e.g. Armenian gini, Latin vinum, Ancient Greek οἶνος, Russian вино [vʲɪˈno]), Kartvelian (e.g. Georgian ღვინო [ɣvinɔ]), and Semitic (*wayn; Hebrew יין [jajin]), pointing to the possibility of a common origin of the word denoting "wine" in these language families.[61] The Georgian word goes back to Proto-Kartvelian *ɣwino-,[62] which is either a borrowing from Proto-Indo-European[62][63][64][65][66][67] or the lexeme was specifically borrowed from Proto-Armenian *ɣʷeinyo-, whence Armenian gini.[68][69][70][71][62] An alternate hypothesis by Fähnrich supposes *ɣwino-, a native Kartvelian word derived from the verbal root *ɣun- ('to bend').[72] See *ɣwino- for more. All these theories place the origin of the word in the same geographical location, Trans-Caucasia, that has been established based on archeological and biomolecular studies as the origin of viticulture.
+
+The red-wine production process involves extraction of color and flavor components from the grape skin. Red wine is made from dark-colored grape varieties. The actual color of the wine can range from violet, typical of young wines, through red for mature wines, to brown for older red wines. The juice from most purple grapes is actually greenish-white; the red color comes from anthocyan pigments (also called anthocyanins) present in the skin of the grape; exceptions are the relatively uncommon teinturier varieties, which actually have red flesh and produce red juice.
+
+Fermentation of the non-colored grape pulp produces white wine. The grapes from which white wine is produced are typically green or yellow. Some varieties are well-known, such as the Chardonnay, Sauvignon, and Riesling. Other white wines are blended from multiple varieties; Tokay, Sherry, and Sauternes are examples of these. Dark-skinned grapes may be used to produce white wine if the wine-maker is careful not to let the skin stain the wort during the separation of the pulp-juice. Pinot noir, for example, is commonly used to produce champagne.
+
+Dry (non-sweet) white wine is the most common, derived from the complete fermentation of the wort. Sweet wines are produced when the fermentation is interrupted before all the grape sugars are converted into alcohol. Sparkling wines, which are mostly white wines, are produced by not allowing carbon dioxide from the fermentation to escape during fermentation, which takes place in the bottle rather than in the barrel.
+
+A rosé wine incorporates some of the color from the grape skins, but not enough to qualify it as a red wine. It may be the oldest known type of wine, as it is the most straightforward to make with the skin contact method. The pink color can range from a pale orange to a vivid near-purple, depending on the varietals used and wine-making techniques. There are three primary ways to produce rosé wine: skin contact (allowing dark grape skins to stain the wort), saignée (removing juice from the must early in fermentation and continuing fermentation of the juice separately), and blending (uncommon and discouraged in most wine growing regions). Rosé wines can be made still, semi-sparkling, or sparkling, with a wide range of sweetness levels from dry Provençal rosé to sweet White Zinfandels and blushes. Rosé wines are made from a wide variety of grapes all over the world.[73][74]
+
+Wines from other fruits, such as apples and berries, are usually named after the fruit from which they are produced combined with the word "wine" (for example, apple wine and elderberry wine) and are generically called fruit wine or country wine (not to be confused with the French term vin de pays). Other than the grape varieties traditionally used for wine-making, most fruits naturally lack either sufficient fermentable sugars, relatively low acidity, yeast nutrients needed to promote or maintain fermentation, or a combination of these three characteristics. This is probably one of the main reasons why wine derived from grapes has historically been more prevalent by far than other types, and why specific types of fruit wine have generally been confined to regions in which the fruits were native or introduced for other reasons.
+
+Mead, also called honey wine, is created by fermenting honey with water, sometimes with various fruits, spices, grains, or hops. As long as the primary substance fermented is honey, the drink is considered mead.[75] Mead was produced in ancient history throughout Europe, Africa and Asia,[76] and was known in Europe before grape wine.[77]
+
+Other drinks called "wine", such as barley wine and rice wine (e.g. sake), are made from starch-based materials and resemble beer  more than traditional  wine, while ginger wine is fortified with brandy. In these latter cases, the term "wine" refers to the similarity in alcohol content rather than to the production process.[78] The commercial use of the English word "wine" (and its equivalent in other languages) is protected by law in many jurisdictions.[79]
+
+Some UK supermarkets have been criticised for selling “wine based” drinks, which only contain 75% wine, but which are still marketed as wine. The International Organisation of Vine and Wine requires that a "wine based drink" must contain a minimum of 75% wine, but producers do not have to divulge the nature of the remaining 25%.[80]
+
+Wine is usually made from one or more varieties of the European species Vitis vinifera, such as Pinot noir, Chardonnay, Cabernet Sauvignon, Gamay and Merlot. When one of these varieties is used as the predominant grape (usually defined by law as minimums of 75% to 85%), the result is a "varietal" as opposed to a "blended" wine. Blended wines are not necessarily inferior to varietal wines, rather they are a different style of wine-making.[81]
+
+Wine can also be made from other species of grape or from hybrids, created by the genetic crossing of two species. V. labrusca (of which the Concord grape is a cultivar), V. aestivalis, V. rupestris, V. rotundifolia and V. riparia are native North American grapes usually grown to eat fresh or for grape juice, jam, or jelly, and only occasionally made into wine.
+
+Hybridization is different from grafting. Most of the world's vineyards are planted with European V. vinifera vines that have been grafted onto North American species' rootstock, a common practice due to their resistance to phylloxera, a root louse that eventually kills the vine. In the late 19th century, most of Europe's vineyards (excluding some of the driest in the south) were devastated by the infestation, leading to widespread vine deaths and eventual replanting. Grafting is done in every wine-producing region in the world except in Argentina, the Canary Islands and Chile—the only places not yet exposed to the insect.[82]
+
+In the context of wine production, terroir is a concept that encompasses the varieties of grapes used, elevation and shape of the vineyard, type and chemistry of soil, climate and seasonal conditions, and the local yeast cultures.[83] The range of possible combinations of these factors can result in great differences among wines, influencing the fermentation, finishing, and aging processes as well. Many wineries use growing and production methods that preserve or accentuate the aroma and taste influences of their unique terroir.[84] However, flavor differences are less desirable for producers of mass-market table wine or other cheaper wines, where consistency takes precedence. Such producers try to minimize differences in sources of grapes through production techniques such as micro-oxygenation, tannin filtration, cross-flow filtration, thin-film evaporation,
+and spinning cones.[85]
+
+Regulations govern the classification and sale of wine in many regions of the world. European wines tend to be classified by region (e.g. Bordeaux, Rioja and Chianti), while non-European wines are most often classified by grape (e.g. Pinot noir and Merlot). Market recognition of particular regions has recently been leading to their increased prominence on non-European wine labels. Examples of recognized non-European locales include Napa Valley, Santa Clara Valley, Sonoma Valley, Anderson Valley, and Mendocino County in California; Willamette Valley and Rogue Valley in Oregon; Columbia Valley in Washington; Barossa Valley in South Australia; Hunter Valley in New South Wales; Luján de Cuyo in Argentina; Central Valley in Chile; Vale dos Vinhedos in Brazil; Hawke's Bay and Marlborough in New Zealand; and in Canada, the Okanagan Valley of British Columbia, and the Niagara Peninsula and Essex County regions of Ontario are the three largest producers.
+
+Some blended wine names are marketing terms whose use is governed by trademark law rather than by specific wine laws. For example, Meritage (sounds like "heritage") is generally a Bordeaux-style blend of Cabernet Sauvignon and Merlot, but may also include Cabernet Franc, Petit Verdot, and Malbec. Commercial use of the term Meritage is allowed only via licensing agreements with the Meritage Association.
+
+France has various appellation systems based on the concept of terroir, with classifications ranging from Vin de Table ("table wine") at the bottom, through Vin de Pays and Appellation d'Origine Vin Délimité de Qualité Supérieure (AOVDQS), up to Appellation d'Origine Contrôlée (AOC) or similar, depending on the region.[86][87] Portugal has developed a system resembling that of France and, in fact, pioneered this concept in 1756 with a royal charter creating the Demarcated Douro Region and regulating the production and trade of wine.[88] Germany created a similar scheme in 2002, although it has not yet achieved the authority of the other countries' classification systems.[89][90] Spain, Greece and Italy have classifications based on a dual system of region of origin and product quality.[91]
+
+New World wines—those made outside the traditional wine regions of Europe—are usually classified by grape rather than by terroir or region of origin, although there have been unofficial attempts to classify them by quality.[92][93][needs update]
+
+According to Canadian Food and Drug Regulations, wine in Canada is an alcoholic drink that is produced by the complete or partial alcoholic fermentation of fresh grapes, grape must, products derived solely from fresh grapes, or any combination of them. There are many materials added during the course of the manufacture, such as yeast, concentrated grape juice, dextrose, fructose, glucose or glucose solids, invert sugar, sugar, or aqueous solutions. Calcium sulphate in such quantity that the content of soluble sulphates in the finished wine shall not exceed 0.2 per cent weight by volume calculated as potassium sulphate. Calcium carbonate in such quantity that the content of tartaric acid in the finished wine shall not be less than 0.15 per cent weight by volume. Also, sulphurous acid, including salts thereof, in such quantity that its content in the finished wine shall not exceed 70 parts per million in the free state, or 350 parts per million in the combined state, calculated as sulphur dioxide. Caramel, amylase and pectinase at a maximum level of use consistent with good manufacturing practice. Brandy, fruit spirit or alcohol derived from the alcoholic fermentation of a food source distilled to not less than 94 per cent alcohol by volume.[clarification needed] Prior to final filtration may be treated with a strongly acid cation exchange resin in the sodium ion form, or a weakly basic anion exchange resin in the hydroxyl ion form.[94]
+
+In the United States, for a wine to be vintage-dated and labeled with a country of origin or American Viticultural Area (AVA; e.g., Sonoma Valley), 95% of its volume must be from grapes harvested in that year.[95] If a wine is not labeled with a country of origin or AVA the percentage requirement is lowered to 85%.[95]
+
+Vintage wines are generally bottled in a single batch so that each bottle will have a similar taste. Climate's impact on the character of a wine can be significant enough to cause different vintages from the same vineyard to vary dramatically in flavor and quality.[96] Thus, vintage wines are produced to be individually characteristic of the particular vintage and to serve as the flagship wines of the producer. Superior vintages from reputable producers and regions will often command much higher prices than their average ones. Some vintage wines (e.g. Brunello), are only made in better-than-average years.
+
+For consistency, non-vintage wines can be blended from more than one vintage, which helps wine-makers sustain a reliable market image and maintain sales even in bad years.[97][98] One recent study suggests that for the average wine drinker, the vintage year may not be as significant for perceived quality as had been thought, although wine connoisseurs continue to place great importance on it.[99]
+
+Wine tasting is the sensory examination and evaluation of wine. Wines contain many chemical compounds similar or identical to those in fruits, vegetables, and spices. The sweetness of wine is determined by the amount of residual sugar in the wine after fermentation, relative to the acidity present in the wine. Dry wine, for example, has only a small amount of residual sugar. Some wine labels suggest opening the bottle and letting the wine "breathe" for a couple of hours before serving, while others recommend drinking it immediately. Decanting (the act of pouring a wine into a special container just for breathing) is a controversial subject among wine enthusiasts. In addition to aeration, decanting with a filter allows the removal of bitter sediments that may have formed in the wine. Sediment is more common in older bottles, but aeration may benefit younger wines.[100]
+
+During aeration, a younger wine's exposure to air often "relaxes" the drink, making it smoother and better integrated in aroma, texture, and flavor. Older wines generally fade (lose their character and flavor intensity) with extended aeration.[101] Despite these general rules, breathing does not necessarily benefit all wines. Wine may be tasted as soon as the bottle is opened to determine how long it should be aerated, if at all.[102][better source needed] When tasting wine, individual flavors may also be detected, due to the complex mix of organic molecules (e.g. esters and terpenes) that grape juice and wine can contain. Experienced tasters can distinguish between flavors characteristic of a specific grape and flavors that result from other factors in wine-making. Typical intentional flavor elements in wine—chocolate, vanilla, or coffee—are those imparted by aging in oak casks rather than the grape itself.[103]
+
+Vertical and horizontal tasting involves a range of vintages within the same grape and vineyard, or the latter in which there is one vintage from multiple vineyards. "Banana" flavors (isoamyl acetate) are the product of yeast metabolism, as are spoilage aromas such as "medicinal" or "Band-Aid" (4-ethylphenol), "spicy" or "smoky" (4-ethylguaiacol),[104] and rotten egg (hydrogen sulfide).[105] Some varieties can also exhibit a mineral flavor due to the presence of water-soluble salts as a result of limestone's presence in the vineyard's soil. Wine aroma comes from volatile compounds released into the air.[106] Vaporization of these compounds can be accelerated by twirling the wine glass or serving at room temperature. Many drinkers prefer to chill red wines that are already highly aromatic, like Chinon and Beaujolais.[107]
+
+The ideal temperature for serving a particular wine is a matter of debate by wine enthusiasts and sommeliers, but some broad guidelines have emerged that will generally enhance the experience of tasting certain common wines. A white wine should foster a sense of coolness, achieved by serving at "cellar temperature" (13 °C (55 °F)). Light red wines drunk young should also be brought to the table at this temperature, where they will quickly rise a few degrees.  Red wines are generally perceived best when served chambré ("at room temperature"). However, this does not mean the temperature of the dining room—often around 21 °C (70 °F)—but rather the coolest room in the house and, therefore, always slightly cooler than the dining room itself.  Pinot noir should be brought to the table for serving at 16 °C (61 °F) and will reach its full bouquet at 18 °C (64 °F). Cabernet Sauvignon, zinfandel, and Rhone varieties should be served at 18 °C (64 °F) and allowed to warm on the table to 21 °C (70 °F) for best aroma.[108]
+
+Outstanding vintages from the best vineyards may sell for thousands of dollars per bottle, though the broader term "fine wine" covers those typically retailing in excess of US$30–50.[109] "Investment wines" are considered by some to be Veblen goods: those for which demand increases rather than decreases as their prices rise.
+Particular selections have higher value, such as "Verticals", in which a range of vintages of a specific grape and vineyard, are offered. The most notable was a Château d'Yquem 135 year vertical containing every vintage from 1860 to 2003 sold for $1.5 million.
+The most common wines purchased for investment include those from Bordeaux and Burgundy; cult wines from Europe and elsewhere; and vintage port. Characteristics of highly collectible wines include:
+
+Investment in fine wine has attracted those who take advantage of their victims' relative ignorance of this wine market sector.[110] Such wine fraudsters often profit by charging excessively high prices for off-vintage or lower-status wines from well-known wine regions, while claiming that they are offering a sound investment unaffected by economic cycles. As with any investment, thorough research is essential to making an informed decision.
+
+* May include official, semi-official or estimated data.
+
+Wine grapes grow almost exclusively between 30 and 50 degrees latitude north and south of the equator. The world's southernmost vineyards are in the Central Otago region of New Zealand's South Island near the 45th parallel south,[112] and the northernmost are in Flen, Sweden, just north of the 59th parallel north.[113]
+
+* May include official, semi-official or estimated data.
+
+
+
+
+
+The UK was the world's largest importer of wine in 2007.[115]
+
+Wine-consumption data from a list of countries by alcohol consumption measured in liters of pure ethyl alcohol consumed per capita in a given year, according to the most recent data from the World Health Organization. The methodology includes persons 15 years of age or older.[118] About 40% of individuals above the legal drinking age consider themselves "wine drinkers", which is higher than all other alcoholic beverages combined (34%) and those who do not drink at all (26%).[119]
+
+
+
+
+
+Wine is a popular and important drink that accompanies and enhances a wide range of cuisines, from the simple and traditional stews to the most sophisticated and complex haute cuisines. Wine is often served with dinner. Sweet dessert wines may be served with the dessert course. In fine restaurants in Western countries, wine typically accompanies dinner. At a restaurant, patrons are helped to make good food-wine pairings by the restaurant's sommelier or wine waiter. Individuals dining at home may use wine guides to help make food–wine pairings. Wine is also drunk without the accompaniment of a meal in wine bars or with a selection of cheeses (at a wine and cheese party). Wines are also used as a theme for organizing various events such as festivals around the world; the city of Kuopio in North Savonia, Finland is known for its annual Kuopio Wine Festivals (Kuopion viinijuhlat).[120]
+
+Wine is important in cuisine not just for its value as a drink, but as a flavor agent, primarily in stocks and braising, since its acidity lends balance to rich savory or sweet dishes.[121] Wine sauce is an example of a culinary sauce that uses wine as a primary ingredient.[122] Natural wines may exhibit a broad range of alcohol content, from below 9% to above 16% ABV, with most wines being in the 12.5–14.5% range.[123] Fortified wines (usually with brandy) may contain 20% alcohol or more.
+
+The use of wine in ancient Near Eastern and Ancient Egyptian religious ceremonies was common. Libations often included wine, and the religious mysteries of Dionysus used wine as a sacramental entheogen to induce a mind-altering state.
+
+Baruch atah Hashem (Ado-nai) Eloheinu melech ha-olam, boray p'ree hagafen – Praised be the Lord, our God, King of the universe, Creator of the fruit of the vine.
+
+Wine is an integral part of Jewish laws and traditions. The Kiddush is a blessing recited over wine or grape juice to sanctify the Shabbat. On Pesach (Passover) during the Seder, it is a Rabbinic obligation of adults to drink four cups of wine.[124] In the Tabernacle and in the Temple in Jerusalem, the libation of wine was part of the sacrificial service.[125] Note that this does not mean that wine is a symbol of blood, a common misconception that contributes to the Christian beliefs of the blood libel.
+"It has been one of history's cruel ironies that the blood libel—accusations against Jews using the blood of murdered gentile children for the making of wine and matzot—became the false pretext for numerous pogroms. And due to the danger, those who live in a place where blood libels occur are halachically exempted from using red wine, lest it be seized as "evidence" against them."[126]
+
+In Christianity, wine is used in a sacred rite called the Eucharist, which originates in the Gospel account of the Last Supper (Gospel of Luke 22:19) describing Jesus sharing bread and wine with his disciples and commanding them to "do this in remembrance of me." Beliefs about the nature of the Eucharist vary among denominations (see Eucharistic theologies contrasted).
+
+While some Christians consider the use of wine from the grape as essential for the validity of the sacrament, many Protestants also allow (or require)  pasteurized grape juice as a substitute. Wine was used in Eucharistic rites by all Protestant groups until an alternative arose in the late 19th century. Methodist dentist and prohibitionist Thomas Bramwell Welch applied new pasteurization techniques to stop the natural fermentation process of grape juice. Some Christians who were part of the growing temperance movement pressed for a switch from wine to grape juice, and the substitution spread quickly over much of the United States, as well as to other countries to a lesser degree.[127] There remains an ongoing debate between some American Protestant denominations as to whether wine can and should be used for the Eucharist or allowed as an ordinary drink, with Catholics and some mainline Protestants allowing wine drinking in moderation, and some conservative Protestant groups opposing consumption of alcohol altogether.[citation needed]
+
+The earliest viticulture tradition in the Southwestern United States starts with sacramental wine, beginning in the 1600s, with Christian friars and monks producing New Mexico wine.[128]
+
+Alcoholic drinks, including wine, are forbidden under most interpretations of Islamic law.[129] In many Muslim countries, possession or consumption of alcoholic drinks carry legal penalties. Iran had previously had a thriving wine industry that disappeared after the Islamic Revolution in 1979.[130] In Greater Persia, mey (Persian wine) was a central theme of poetry for more than a thousand years, long before the advent of Islam. Some Alevi sects – one of the two main branches of Islam in Turkey (the other being Sunni Islam) – use wine in their religious services.[citation needed]
+
+Certain exceptions to the ban on alcohol apply. Alcohol derived from a source other than the grape (or its byproducts) and the date[131] is allowed in "very small quantities" (loosely defined as a quantity that does not cause intoxication) under the Sunni Hanafi madhab, for specific purposes (such as medicines), where the goal is not intoxication. However, modern Hanafi scholars regard alcohol consumption as totally forbidden.[132]
+
+Wine contains ethyl alcohol, the same chemical that is present in beer and distilled spirits and as such, wine consumption has short-term psychological and physiological effects on the user. Different concentrations of alcohol in the human body have different effects on a person. The effects of alcohol depend on the amount an individual has drunk, the percentage of alcohol in the wine and the timespan that the consumption took place, the amount of food eaten and whether an individual has taken other prescription, over-the-counter or street drugs, among other factors. Drinking enough to cause a blood alcohol concentration (BAC) of 0.03%-0.12% typically causes an overall improvement in mood and possible euphoria, increased self-confidence and sociability, decreased anxiety, a flushed, red appearance in the face and impaired judgment and fine muscle coordination. A BAC of 0.09% to 0.25% causes lethargy, sedation, balance problems and blurred vision. A BAC from 0.18% to 0.30% causes profound confusion, impaired speech (e.g. slurred speech), staggering, dizziness and vomiting. A BAC from 0.25% to 0.40% causes stupor, unconsciousness, anterograde amnesia, vomiting, and death may occur due to inhalation of vomit (pulmonary aspiration) while unconscious and respiratory depression (potentially life-threatening). A BAC from 0.35% to 0.80% causes a coma (unconsciousness), life-threatening respiratory depression and possibly fatal alcohol poisoning. As with all alcoholic drinks, drinking while driving, operating an aircraft or heavy machinery increases the risk of an accident; many countries have penalties against drunk driving.
+
+Wines can trigger positive emotions in a short period of time, such as feelings of relaxation and comfort. The context and quality of wine can affect the mood and emotions, too.[133]
+
+The main active ingredient of wine is alcohol, and therefore, the health effects of alcohol apply to wine. A 2016 systematic review and meta-analysis found that moderate ethanol consumption brought no mortality benefit compared with lifetime abstention from ethanol consumption.[134] A systematic analysis of data from the Global Burden of Disease study found that consumption of ethanol increases the risk of cancer and increases the risk of all-cause mortality, and that the level of ethanol consumption that minimizes disease is zero consumption.[135] Some studies have concluded that drinking small quantities of alcohol (less than one drink in women and two in men)[how often?] is associated with a decreased risk of heart disease, stroke, diabetes mellitus, and early death.[136]  Drinking more than this amount actually increases the risk of heart disease, high blood pressure, atrial fibrillation, and stroke. Some of these studies lumped former ethanol drinkers and life-long abstainers into a single group of nondrinkers, hiding the health benefits of life-long abstention from ethanol.[136] Risk is greater in younger people due to binge drinking which may result in violence or accidents.[136] About 3.3 million deaths (5.9% of all deaths) are believed to be due to alcohol each year.[137]
+
+Alcoholism is a broad term for any drinking of alcohol that results in problems.[138] It was previously divided into two types: alcohol abuse and alcohol dependence.[139][140] In a medical context, alcoholism is said to exist when two or more of the following conditions is present: a person drinks large amounts over a long time period, has difficulty cutting down, acquiring and drinking alcohol takes up a great deal of time, alcohol is strongly desired, usage results in not fulfilling responsibilities, usage results in social problems, usage results in health problems, usage results in risky situations, withdrawal occurs when stopping, and alcohol tolerance has occurred with use.[140] Alcoholism reduces a person's life expectancy by around ten years[141] and alcohol use is the third leading cause of early death in the United States.[136] No professional medical association recommends that people who are nondrinkers should start drinking wine.[136][142]
+
+Excessive consumption of alcohol can cause liver cirrhosis and alcoholism.[143] The American Heart Association "cautions people NOT to start drinking ... if they do not already drink alcohol. Consult your doctor on the benefits and risks of consuming alcohol in moderation."[144]
+
+Population studies exhibit a J-curve correlation between wine consumption and rates of heart disease: heavy drinkers have an elevated rate, while people who drink small amount (up to 20 g of alcohol per day, approximately 200 ml (7 imp fl oz; 7 US fl oz) of 12.7% ABV wine) have a lower rate than non-drinkers. Studies have also found that moderate consumption of other alcoholic drinks is correlated with decreased mortality from cardiovascular causes,[145] although the association is stronger for wine. Additionally, some studies have found a greater correlation of health benefits with red than white wine, though other studies have found no difference. Red wine contains more polyphenols than white wine, and these could be protective against cardiovascular disease.[146]
+
+Although red wine contains the chemical resveratrol and there is tentative evidence it may improve heart health, the evidence is unclear for those at high risk as of 2013[update].[147] Grape skins naturally produce resveratrol in response to fungal infection, including exposure to yeast during fermentation. White wine generally contains lower levels of the chemical as it has minimal contact with grape skins during this process.[148]
+
+Incidents of fraud, such as mislabeling the origin or quality of wines, have resulted in regulations on labeling. "Wine scandals" that have received media attention include:
+
+Most wines are sold in glass bottles and sealed with corks (50% of which come from Portugal).[152] An increasing number of wine producers have been using alternative closures such as screwcaps and synthetic plastic "corks". Although alternative closures are less expensive and prevent cork taint, they have been blamed for such problems as excessive reduction.[153]
+
+Some wines are packaged in thick plastic bags within corrugated fiberboard boxes, and are called "box wines", or "cask wine". Tucked inside the package is a tap affixed to the bag in box, or bladder, that is later extended by the consumer for serving the contents. Box wine can stay acceptably fresh for up to a month after opening because the bladder collapses as wine is dispensed, limiting contact with air and, thus, slowing the rate of oxidation. In contrast, bottled wine oxidizes more rapidly after opening because of the increasing ratio of air to wine as the contents are dispensed; it can degrade considerably in a few days. Cans are one of the fastest-growing forms of alternative wine packaging on the market.[154]
+
+Environmental considerations of wine packaging reveal benefits and drawbacks of both bottled and box wines. The glass used to make bottles is a nontoxic, naturally occurring substance that is completely recyclable, whereas the plastics used for box-wine containers are typically much less environmentally friendly. However, wine-bottle manufacturers have been cited for Clean Air Act violations. A New York Times editorial suggested that box wine, being lighter in package weight, has a reduced carbon footprint from its distribution; however, box-wine plastics, even though possibly recyclable, can be more labor-intensive (and therefore expensive) to process than glass bottles. In addition, while a wine box is recyclable, its plastic bladder most likely is not.[155] Some people are drawn to canned wine due to its portability and recyclable packaging.[154]
+
+Some wine is sold in stainless steel kegs and is referred to as wine on tap.
+
+Wine cellars, or wine rooms, if they are above-ground, are places designed specifically for the storage and aging of wine. Fine restaurants and some private homes have wine cellars. In an active wine cellar, temperature and humidity are maintained by a climate-control system. Passive wine cellars are not climate-controlled, and so must be carefully located. Because wine is a natural, perishable food product, all types—including red, white, sparkling, and fortified—can spoil when exposed to heat, light, vibration or fluctuations in temperature and humidity. When properly stored, wines can maintain their quality and in some cases improve in aroma, flavor, and complexity as they age. Some wine experts contend that the optimal temperature for aging wine is 13 °C (55 °F),[156] others 15 °C (59 °F).[157]
+
+Wine refrigerators offer a smaller alternative to wine cellars and are available in capacities ranging from small, 16-bottle units to furniture-quality pieces that can contain 400 bottles. Wine refrigerators are not ideal for aging, but rather serve to chill wine to the proper temperature for drinking. These refrigerators keep the humidity low (usually under 50%), below the optimal humidity of 50% to 70%. Lower humidity levels can dry out corks over time, allowing oxygen to enter the bottle, which reduces the wine's quality through oxidation.[158] While some types of alcohol are sometimes stored in freezer, such as vodka, it is not possible to safely freeze wine in the bottle, as there is insufficient room for it to expand as it freezes and the bottle will usually crack. Certain shapes of bottle may allow the cork to be pushed out by the ice, but if the bottle is frozen on its side, the wine in the narrower neck will invariably freeze first, preventing this.
+
+There are a large number of occupations and professions that are part of the wine industry, ranging from the individuals who grow the grapes, prepare the wine, bottle it, sell it, assess it, market it and finally make recommendations to clients and serve the wine.
+

en/5997.html.txt

@@ -0,0 +1,185 @@
+
+
+The violin, sometimes known as a fiddle, is a wooden string instrument in the violin family. Most violins have a hollow wooden body. It is the smallest and highest-pitched instrument (soprano) in the family in regular use.[a] The violin typically has four strings, usually tuned in perfect fifths with notes G3, D4, A4, E5, and is most commonly played by drawing a bow across its strings. It can also be played by plucking the strings with the fingers (pizzicato) and, in specialized cases, by striking the strings with the wooden side of the bow (col legno).
+
+Violins are important instruments in a wide variety of musical genres. They are most prominent in the Western classical tradition, both in ensembles (from chamber music to orchestras) and as solo instruments. Violins are also important in many varieties of folk music, including country music, bluegrass music and in jazz. Electric violins with solid bodies and piezoelectric pickups are used in some forms of rock music and jazz fusion, with the pickups plugged into instrument amplifiers and speakers to produce sound. The violin has come to be incorporated in many non-Western music cultures, including Indian music and Iranian music. The name fiddle is often used regardless of the type of music played on it.
+
+The violin was first known in 16th-century Italy, with some further modifications occurring in the 18th and 19th centuries to give the instrument a more powerful sound and projection. In Europe, it served as the basis for the development of other stringed instruments used in Western classical music, such as the viola.[1][2][3]
+
+Violinists and collectors particularly prize the fine historical instruments made by the Stradivari, Guarneri, Guadagnini and Amati families from the 16th to the 18th century in Brescia and Cremona (Italy) and by Jacob Stainer in Austria. According to their reputation, the quality of their sound has defied attempts to explain or equal it, though this belief is disputed.[4][5] Great numbers of instruments have come from the hands of less famous makers, as well as still greater numbers of mass-produced commercial "trade violins" coming from cottage industries in places such as Saxony, Bohemia, and Mirecourt. Many of these trade instruments were formerly sold by Sears, Roebuck and Co. and other mass merchandisers.
+
+The components of a violin are usually made from different types of wood. Violins can be strung with gut, Perlon or other synthetic, or steel strings. A person who makes or repairs violins is called a luthier or violinmaker. One who makes or repairs bows is called an archetier or bowmaker.
+
+The word "violin" was first used in English in the 1570s.[6] The word "violin" comes from "Italian violino, [a] diminutive of viola". The term "viola" comes from the expression for "tenor violin" in 1797, from Italian viola, from Old Provençal viola, [which came from] Medieval Latin vitula" as a term which means "stringed instrument," perhaps [coming] from Vitula, Roman goddess of joy..., or from related Latin verb vitulari, "to exult, be joyful."[7] The related term "Viola da gamba" means "bass viol" (1724) is from Italian, literally "a viola for the leg" (i.e. to hold between the legs)."[7]  A violin is the "modern form of the smaller, medieval viola da braccio." ("arm viola")[6]
+
+The violin is often called a fiddle, either when used in a folk music context, or even in Classical music scenes, as an informal nickname for the instrument.[8] The word "fiddle" was first used in English in the late 14th century.[8] The word "fiddle" comes from "fedele, fydyll, fidel, earlier fithele, from Old English fiðele "fiddle," which is related to Old Norse fiðla, Middle Dutch vedele, Dutch vedel, Old High German fidula, German Fiedel, "a fiddle;" all of uncertain origin." As to the origin of the word "fiddle", the "...usual suggestion, based on resemblance in sound and sense, is that it is from Medieval Latin vitula."[8]
+
+The earliest stringed instruments were mostly plucked (for example, the Greek lyre). Two-stringed, bowed instruments, played upright and strung and bowed with horsehair, may have originated in the nomadic equestrian cultures of Central Asia, in forms closely resembling the modern-day Mongolian Morin huur and the Kazakh Kobyz. Similar and variant types were probably disseminated along east–west trading routes from Asia into the Middle East,[9][10] and the Byzantine Empire.[11][12]
+
+The direct ancestor of all European bowed instruments is the Arabic rebab (ربابة), which developed into the Byzantine lyra by the 9th century and later the European rebec.[13][14][15] The first makers of violins probably borrowed from various developments of the Byzantine lyra. These included the vielle (also known as the fidel or viuola) and the lira da braccio.[11][16]
+The violin in its present form emerged in early 16th-century northern Italy. The earliest pictures of violins, albeit with three strings, are seen in northern Italy around 1530, at around the same time as the words "violino" and "vyollon" are seen in Italian and French documents. One of the earliest explicit descriptions of the instrument, including its tuning, is from the Epitome musical by Jambe de Fer, published in Lyon in 1556.[17] By this time, the violin had already begun to spread throughout Europe.
+
+The violin proved very popular, both among street musicians and the nobility; the French king Charles IX ordered Andrea Amati to construct 24 violins for him in 1560.[18] One of these "noble" instruments, the Charles IX, is the oldest surviving violin. The finest Renaissance carved and decorated violin in the world is the Gasparo da Salò (c.1574) owned by Ferdinand II, Archduke of Austria and later, from 1841, by the Norwegian virtuoso Ole Bull, who used it for forty years and thousands of concerts, for its very powerful and beautiful tone, similar to that of a Guarneri.[19] "The Messiah" or "Le Messie" (also known as the "Salabue") made by Antonio Stradivari in 1716 remains pristine. It is now located in the Ashmolean Museum of Oxford.[20]
+
+The most famous violin makers (luthiers) between the 16th century and the 18th century include:
+
+Significant changes occurred in the construction of the violin in the 18th century, particularly in the length and angle of the neck, as well as a heavier bass bar. The majority of old instruments have undergone these modifications, and hence are in a significantly different state than when they left the hands of their makers, doubtless with differences in sound and response.[23] But these instruments in their present condition set the standard for perfection in violin craftsmanship and sound, and violin makers all over the world try to come as close to this ideal as possible.
+
+To this day, instruments from the so-called Golden Age of violin making, especially those made by Stradivari, Guarneri del Gesù and Montagnana are the most sought-after instruments by both collectors and performers.  The current record amount paid for a Stradivari violin is £9.8 million (US$15.9 million at that time), when the instrument known as the Lady Blunt was sold by Tarisio Auctions in an online auction on June 20, 2011.[24]
+
+A violin generally consists of a spruce top (the soundboard, also known as the top plate, table, or belly), maple ribs and back, two endblocks, a neck, a bridge, a soundpost, four strings, and various fittings, optionally including a chinrest, which may attach directly over, or to the left of, the tailpiece. A distinctive feature of a violin body is its hourglass-like shape and the arching of its top and back. The hourglass shape comprises two upper bouts, two lower bouts, and two concave C-bouts at the waist, providing clearance for the bow. The "voice" or sound of a violin depends on its shape, the wood it is made from, the graduation (the thickness profile) of both the top and back, the varnish that coats its outside surface and the skill of the luthier in doing all of these steps. The varnish and especially the wood continue to improve with age, making the fixed supply of old well-made violins built by famous luthiers much sought-after.
+
+The majority of glued joints in the instrument use animal hide glue rather than common white glue for a number of reasons. Hide glue is capable of making a thinner joint than most other glues, it is reversible (brittle enough to crack with carefully applied force, and removable with very warm water) when disassembly is needed, and since fresh hide glue sticks to old hide glue, more original wood can be preserved when repairing a joint. (More modern glues must be cleaned off entirely for the new joint to be sound, which generally involves scraping off some wood along with the old glue.) Weaker, diluted glue is usually used to fasten the top to the ribs, and the nut to the fingerboard, since common repairs involve removing these parts. The purfling running around the edge of the spruce top provides some protection against cracks originating at the edge. It also allows the top to flex more independently of the rib structure. Painted-on faux purfling on the top is usually a sign of an inferior instrument. The back and ribs are typically made of maple, most often with a matching striped figure, referred to as flame, fiddleback, or tiger stripe.
+
+The neck is usually maple with a flamed figure compatible with that of the ribs and back. It carries the fingerboard, typically made of ebony, but often some other wood stained or painted black on cheaper instruments. Ebony is the preferred material because of its hardness, beauty, and superior resistance to wear. Fingerboards are dressed to a particular transverse curve, and have a small lengthwise "scoop," or concavity, slightly more pronounced on the lower strings, especially when meant for gut or synthetic strings. Some old violins (and some made to appear old) have a grafted scroll, evidenced by a glue joint between the pegbox and neck. Many authentic old instruments have had their necks reset to a slightly increased angle, and lengthened by about a centimeter. The neck graft allows the original scroll to be kept with a Baroque violin when bringing its neck into conformance with modern standards.
+
+The bridge is a precisely cut piece of maple that forms the lower anchor point of the vibrating length of the strings and transmits the vibration of the strings to the body of the instrument. Its top curve holds the strings at the proper height from the fingerboard in an arc, allowing each to be sounded separately by the bow. The sound post, or soul post, fits precisely inside the instrument between the back and top, at a carefully chosen spot near the treble foot of the bridge, which it helps support. It also influences the modes of vibration of the top and the back of the instrument.
+
+The tailpiece anchors the strings to the lower bout of the violin by means of the tailgut, which loops around an ebony button called the tailpin (sometimes confusingly called the endpin, like the cello's spike), which fits into a tapered hole in the bottom block. Very often the E string will have a fine tuning lever worked by a small screw turned by the fingers. Fine tuners may also be applied to the other strings, especially on a student instrument, and are sometimes built into the tailpiece. The fine tuners enable the performer to make small changes in the pitch of a string. At the scroll end, the strings wind around the wooden tuning pegs in the pegbox. The tuning pegs are tapered and fit into holes in the peg box. The tuning pegs are held in place by the friction of wood on wood. Strings may be made of metal or less commonly gut or gut wrapped in metal. Strings usually have a colored silk wrapping at both ends, for identification of the string (e.g., G string, D string, A string or E string) and to provide friction against the pegs. The tapered pegs allow friction to be increased or decreased by the player applying appropriate pressure along the axis of the peg while turning it.
+
+Strings were first made of sheep gut (commonly known as catgut, which despite the name, did not come from cats), or simply gut, which was stretched, dried, and twisted. In the early years of the 20th century, strings were made of either gut or steel. Modern strings may be gut, solid steel, stranded steel, or various synthetic materials such as perlon, wound with various metals, and sometimes plated with silver. Most E strings are unwound, either plain or plated steel. Gut strings are not as common as they once were, but many performers use them to achieve a specific sound especially in historically informed performance of Baroque music. Strings have a limited lifetime. Eventually, when oil, dirt, corrosion, and rosin accumulate, the mass of the string can become uneven along its length. Apart from obvious things, such as the winding of a string coming undone from wear, players generally change a string when it no longer plays "true" (with good intonation on the harmonics), losing the desired tone, brilliance and intonation. String longevity depends on string quality and playing intensity.
+
+A violin is tuned in fifths, in the notes G3, D4, A4, E5. The lowest note of a violin, tuned normally, is G3, or G below middle C (C4). (On rare occasions, the lowest string may be tuned down by as much as a fourth, to D3.) The highest note is less well defined: E7, the E two octaves above the open string (which is tuned to E5) may be considered a practical limit for orchestral violin parts,[25] but it is often possible to play higher, depending on the length of the fingerboard and the skill of the violinist. Yet higher notes (up to C8) can be sounded by stopping the string, reaching the limit of the fingerboard, and/or by using artificial harmonics.
+
+The arched shape, the thickness of the wood, and its physical qualities govern the sound of a violin. Patterns of the node made by sand or glitter sprinkled on the plates with the plate vibrated at certain frequencies, called Chladni patterns, are occasionally used by luthiers to verify their work before assembling the instrument.[26]
+
+Apart from the standard, full (​4⁄4) size, violins are also made in so-called fractional sizes of ​7⁄8, ​3⁄4, ​1⁄2, ​1⁄4, ​1⁄8, ​1⁄10, ​1⁄16, ​1⁄32 and even ​1⁄64. These smaller instruments are commonly used by young players, whose fingers are not long enough to reach the correct positions on full-sized instruments.
+
+While related in some sense to the dimensions of the instruments, the fractional sizes are not intended to be literal descriptions of relative proportions. For example, a ​3⁄4-sized instrument is not three-quarters the length of a full size instrument. The body length (not including the neck) of a full-size, or ​4⁄4, violin is 356 mm (14.0 in), smaller in some 17th-century models. A ​3⁄4 violin's body length is 335 mm (13.2 in), and a ​1⁄2 size is 310 mm (12.2 in). With the violin's closest family member, the viola, size is specified as body length in inches or centimeters rather than fractional sizes. A full-size viola averages 40 cm (16 in). However, each individual adult will determine which size of viola to use.
+
+Occasionally, an adult with a small frame may use a so-called ​7⁄8 size violin instead of a full-size instrument.  Sometimes called a lady's violin, these instruments are slightly shorter than a full size violin, but tend to be high-quality instruments capable of producing a sound that is comparable to that of fine full size violins. 5 string violin sizes may differ from the normal 4 string.
+
+The instrument which corresponds to the violin in the violin octet is the mezzo violin, tuned the same as a violin but with a slightly longer body. The strings of the mezzo violin are the same length as those of the standard violin. This instrument is not in common use.[27]
+
+Violins are tuned by turning the pegs in the pegbox under the scroll, or by adjusting the fine tuner screws at the tailpiece. All violins have pegs; fine tuners (also called fine adjusters) are optional. Most fine tuners consist of a metal screw that moves a lever attached to the string end. They permit very small pitch adjustments much more easily than the pegs. By turning one clockwise, the pitch becomes sharper (as the string is under more tension) and turning one counterclockwise, the pitch becomes flatter (as the string is under less tension). Fine tuners on all four of the strings are very helpful when using those that have a steel core, and some players use them with synthetic strings as well. Since modern E strings are steel, a fine tuner is nearly always fitted for that string. Fine tuners are not used with gut strings, which are more elastic than steel or synthetic-core strings and do not respond adequately to the very small movements of fine tuners.
+
+To tune a violin, the A string is first tuned to a standard pitch (usually A=440 Hz). (When accompanying or playing with a fixed-pitch instrument such as a piano or accordion, the violin tunes to it. The oboe is generally the instrument used to tune orchestras where violins are present, since its sound is penetrating and can be heard over the other woodwinds) The other strings are then tuned against each other in intervals of perfect fifths by bowing them in pairs. A minutely higher tuning is sometimes employed for solo playing to give the instrument a brighter sound; conversely, Baroque music is sometimes played using lower tunings to make the violin's sound more gentle. After tuning, the instrument's bridge may be examined to ensure that it is standing straight and centered between the inner nicks of the f-holes; a crooked bridge may significantly affect the sound of an otherwise well-made violin. After extensive playing, the holes into which the tuning pegs are inserted can become worn, which can lead the peg to slip under tension. This can lead to the pitch of the string dropping, or if the peg becomes completely loose, to the string completely losing tension. A violin in which the tuning pegs are slipping needs to be repaired by a luthier or violin repairperson. Peg dope or peg compound, used regularly, can delay the onset of such wear, while allowing the pegs to turn smoothly.
+
+The tuning G–D–A–E is used for most violin music, both in Classical music, jazz and folk music. Other tunings are occasionally employed; the G string, for example, can be tuned up to A. The use of nonstandard tunings in classical music is known as scordatura; in some folk styles, it is called cross tuning. One famous example of scordatura in classical music is Camille Saint-Saëns' Danse Macabre, where the solo violin's E string is tuned down to E♭ to impart an eerie dissonance to the composition. Other examples are the third movement of Contrasts, by Béla Bartók, where the E string is tuned down to E♭ and the G tuned to a G♯, and the Mystery Sonatas by Biber, in which each movement has different scordatura tuning.
+
+In Indian classical music and Indian light music, the violin is likely to be tuned to D♯–A♯–D♯–A♯ in the South Indian style. As there is no concept of absolute pitch in Indian classical music, any convenient tuning maintaining these relative pitch intervals between the strings can be used. Another prevalent tuning with these intervals is B♭–F–B♭–F, which corresponds to Sa–Pa–Sa–Pa in the Indian carnatic classical music style. In the North Indian Hindustani style, the tuning is usually Pa-Sa-Pa-Sa instead of Sa–Pa–Sa–Pa. This could correspond to F–B♭–F–B♭, for instance. In Iranian classical music and Iranian light music, the violin ls different tunings in any Dastgah, the violin is likely to be tuned (E–A–E–A) in Dastgah-h Esfahan or in  Dastgāh-e Šur is (E–A–D–E) and (E–A–E–E), in Dastgāh-e Māhur is (E–A–D–A). In Arabic classical music, the A and E strings are lowered by a whole step i.e. G–D–G–D. This is to ease playing Arabic maqams, especially those containing quarter tones.
+
+While most violins have four strings, there are violins with additional strings. Some have as many as seven strings. Seven strings is generally thought to be the maximum number of strings that can be put on a bowed string instrument, because with more than seven strings, it would be impossible to play a particular inner string individually with the bow. Instruments with seven strings are very rare. The extra strings on such violins typically are lower in pitch than the G-string; these strings are usually tuned to C, F, and B♭. If the instrument's playing length, or string length from nut to bridge, is equal to that of an ordinary full-scale violin; i.e., a bit less than 13 inches (33 cm), then it may be properly termed a violin. Some such instruments are somewhat longer and should be regarded as violas. Violins with five strings or more are typically used in jazz or folk music. Some custom-made instruments have extra strings which are not bowed, but which sound sympathetically, due to the vibrations of the bowed strings.
+
+A violin is usually played using a bow consisting of a stick with a ribbon of horsehair strung between the tip and frog (or nut, or heel) at opposite ends. A typical violin bow may be 75 cm (30 in) overall, and weigh about 60 g (2.1 oz). Viola bows may be about 5 mm (0.20 in) shorter and 10 g (0.35 oz) heavier. At the frog end, a screw adjuster tightens or loosens the hair. Just forward of the frog, a leather thumb cushion, called the grip, and winding protect the stick and provide a strong grip for the player's hand. Traditional windings are of wire (often silver or plated silver), silk, or baleen ("whalebone", now substituted by alternating strips of tan and black plastic.) Some fiberglass student bows employ a plastic sleeve as grip and winding.
+
+Bow hair traditionally comes from the tail of a grey male horse (which has predominantly white hair). Some cheaper bows use synthetic fiber. Solid rosin is rubbed onto the hair, to render it slightly sticky; when the bow is drawn across a string, the friction between them makes the string vibrate. Traditional materials for the more costly bow sticks include snakewood, and brazilwood (which is also known as Pernambuco wood). Some recent bow design innovations use carbon fiber (CodaBows) for the stick, at all levels of craftsmanship. Inexpensive bows for students are made of less costly timbers, or from fiberglass (Glasser).
+
+The violin is played either seated or standing up. Solo players (whether playing alone, with a piano or with an orchestra) play mostly standing up (unless prevented by a physical disability such as in the case of Itzhak Perlman), while in the orchestra and in chamber music it is usually played seated. In the 2000s and 2010s, some orchestras performing Baroque music (such as the Freiburg Baroque Orchestra) have had all of their violins and violas, solo and ensemble, perform standing up.
+
+The standard way of holding the violin is with the left side of the jaw resting on the chinrest of the violin, and supported by the left shoulder, often assisted by a shoulder rest (or a sponge and an elastic band for younger players who struggle with shoulder rests). The jaw and the shoulder must hold the violin firmly enough to allow it to remain stable when the left hand goes from a high position (a high pitched note far up on the fingerboard) to a low one (nearer to the pegbox). In the Indian posture, the stability of the violin is guaranteed by its scroll resting on the side of the foot.
+
+While teachers point out the vital importance of good posture both for the sake of the quality of the playing and to reduce the chance of repetitive strain injury, advice as to what good posture is and how to achieve it differs in details. However, all insist on the importance of a natural relaxed position without tension or rigidity. Things which are almost universally recommended is keeping the left wrist straight (or very nearly so) to allow the fingers of the left hand to move freely and to reduce the chance of injury and keeping either shoulder in a natural relaxed position and avoiding raising either of them in an exaggerated manner. This, like any other unwarranted tension, would limit freedom of motion, and increase the risk of injury.
+
+Hunching can hamper good playing because it throws the body off balance and makes the shoulders rise. Another sign that comes from unhealthy tension is pain in the left hand, which indicates too much pressure when holding the violin.
+
+The left hand determines the sounding length of the string, and thus the pitch of the string, by "stopping" it (pressing it) against the fingerboard with the fingertips, producing different pitches. As the violin has no frets to stop the strings, as is usual with the guitar, the player must know exactly where to place the fingers on the strings to play with good intonation (tuning). Beginning violinists play open strings and the lowest position, nearest to the nut. Students often start with relatively easy keys, such as A Major and G major. Students are taught scales and simple melodies. Through practice of scales and arpeggios and ear training, the violinist's left hand eventually "finds" the notes intuitively by muscle memory.
+
+Beginners sometimes rely on tapes placed on the fingerboard for proper left hand finger placement, but usually abandon the tapes quickly as they advance. Another commonly used marking technique uses dots of white-out on the fingerboard, which wear off in a few weeks of regular practice. This practice, unfortunately, is used sometimes in lieu of adequate ear-training, guiding the placement of fingers by eye and not by ear. Especially in the early stages of learning to play, the so-called "ringing tones" are useful. There are nine such notes in first position, where a stopped note sounds a unison or octave with another (open) string, causing it to resonate sympathetically. Students often use these ringing tones to check the intonation of the stopped note by seeing if it is harmonious with the open string. For example, when playing the stopped pitch "A" on the G string, the violinist could play the open D string at the same time, to check the intonation of the stopped "A". If the "A" is in tune, the "A" and the open D string should produce a harmonious perfect fourth.
+
+Violins are tuned in perfect fifths, like all the orchestral strings (violin, viola, cello) except the double bass, which is tuned in perfect fourths. Each subsequent note is stopped at a pitch the player perceives as the most harmonious, "when unaccompanied, [a violinist] does not play consistently in either the tempered or the natural [just] scale, but tends on the whole to conform with the Pythagorean scale."[28] When violinists are playing in a string quartet or a string orchestra, the strings typically "sweeten" their tuning to suit the key they are playing in. When playing with an instrument tuned to equal temperament, such as a piano, skilled violinists adjust their tuning to match the equal temperament of the piano to avoid discordant notes.
+
+The fingers are conventionally numbered 1 (index) through 4 (little finger) in music notation, such as sheet music and etude books.  Especially in instructional editions of violin music, numbers over the notes may indicate which finger to use, with 0 or O indicating an open string. The chart to the right shows the arrangement of notes reachable in first position. Not shown on this chart is the way the spacing between note positions becomes closer as the fingers move up (in pitch) from the nut.  The bars at the sides of the chart represent the usual possibilities for beginners' tape placements, at 1st, high 2nd, 3rd, and 4th fingers.
+
+The placement of the left hand on the fingerboard is characterized by "positions".  First position, where most beginners start (although some methods start in third position), is the most commonly used position in string music. Music composed for beginning youth orchestras is often mostly in first position. The lowest note available in this position in standard tuning is an open G; the highest note in first position is played with the fourth finger on the E-string, sounding a B. Moving the hand up the neck, so the first finger takes the place of the second finger, brings the player into second position. Letting the first finger take the first-position place of the third finger brings the player to third position, and so on. A change of positions, with its associated movement of the hand, is referred to as a shift, and effective shifting maintaining accurate intonation and a smooth legato (connected) sound is a key element of technique at all levels. Often a "guide finger" is used; the last finger to play a note in the old position continuously lightly touches the string during the course of the shift to end up on its correct place in the new position. In elementary shifting exercises the "guide finger" is often voiced while it glides up and down the string, so the player can establish by ear whether they are landing in the correct place, however outside of these exercises it should rarely be audible (unless the performer is consciously applying a portamento effect for expressive reasons).
+
+In the course of a shift in low positions, the thumb of the left hand moves up or down the neck of the instrument so as to remain in the same position relative to the fingers (though the movement of the thumb may occur slightly before, or slightly after, the movement of the fingers). In such positions, the thumb is often thought of as an 'anchor' whose location defines what position the player is in. In very high positions, the thumb is unable to move with the fingers as the body of the instrument gets in the way. Instead, the thumb works around the neck of the instrument to sit at the point at which the neck meets the right bout of the body, and remains there while the fingers move between the high positions.
+
+A note played outside of the normal compass of a position, without any shift, is referred to as an extension. For instance, in third position on the A string, the hand naturally sits with the first finger on D♮ and the fourth on either G♮ or G♯. Stretching the first finger back down to a C♯, or the fourth finger up to an A♮, forms an extension. Extensions are commonly used where one or two notes are slightly out of an otherwise solid position, and give the benefit of being less intrusive than a shift or string crossing. The lowest position on the violin is referred to as "half position". In this position the first finger is on a "low first position" note, e.g. B♭ on the A string, and the fourth finger is in a downward extension from its regular position, e.g. D♮ on the A string, with the other two fingers placed in between as required. As the position of the thumb is typically the same in "half position" as in first position, it is better thought of as a backwards extension of the whole hand than as a genuine position.
+
+The upper limit of the violin's range is largely determined by the skill of the player, who may easily play more than two octaves on a single string, and four octaves on the instrument as a whole. Position names are mostly used for the lower positions and in method books and etudes; for this reason, it is uncommon to hear references to anything higher than seventh position. The highest position, practically speaking, is 13th position. Very high positions are a particular technical challenge, for two reasons. Firstly, the difference in location of different notes becomes much narrower in high positions, making the notes more challenging to locate and in some cases to distinguish by ear. Secondly, the much shorter sounding length of the string in very high positions is a challenge for the right arm and bow in sounding the instrument effectively. The finer (and more expensive) an instrument, the better able it is to sustain good tone right to the top of the fingerboard, at the highest pitches on the E string.
+
+All notes (except those below the open D) can be played on more than one string. This is a standard design feature of stringed instruments; however, it differs from the piano, which has only one location for each of its 88 notes. For instance, the note of open A on the violin can be played as the open A, or on the D string (in first to fourth positions) or even on the G string (very high up in sixth to ninth positions). Each string has a different tone quality, because of the different weights (thicknesses) of the strings and because of the resonances of other open strings. For instance, the G string is often regarded as having a very full, sonorous sound which is particularly appropriate to late Romantic music. This is often indicated in the music by the marking, for example, sul G or IV (a Roman numeral indicating to play on the fourth string; by convention, the strings are numbered from thinnest, highest pitch (I) to the lowest pitch (IV). Even without an explicit instructions in the score, an advanced violinist will use her/his discretion and artistic sensibility to select which string to play specific notes or passages.
+
+If a string is bowed or plucked without any finger stopping it, it is said to be an open string. This gives a different sound from a stopped string, since the string vibrates more freely at the nut than under a finger. Further, it is impossible to use vibrato fully on an open string (though a partial effect can be achieved by stopping a note an octave up on an adjacent string and vibrating that, which introduces an element of vibrato into the overtones). In the classical tradition, violinists will often use a string crossing or shift of position to allow them to avoid the change of timbre introduced by an open string, unless indicated by the composer. This is particularly true for the open E which is often regarded as having a harsh sound. However, there are also situations where an open string may be specifically chosen for artistic effect. This is seen in classical music which is imitating the drone of an organ (J. S. Bach, in his Partita in E for solo violin, achieved this), fiddling (e.g., Hoedown) or where taking steps to avoid the open string is musically inappropriate (for instance in Baroque music where shifting position was less common). In quick passages of scales or arpeggios an open E string may simply be used for convenience if the note does not have time to ring and develop a harsh timbre. In folk music, fiddling and other traditional music genres, open strings are commonly used for their resonant timbre.
+
+Playing an open string simultaneously with a stopped note on an adjacent string produces a bagpipe-like drone, often used by composers in imitation of folk music. Sometimes the two notes are identical (for instance, playing a fingered A on the D string against the open A string), giving a ringing sort of "fiddling" sound. Playing an open string simultaneously with an identical stopped note can also be called for when more volume is required, especially in orchestral playing. Some classical violin parts have notes for which the composer requests the violinist to play an open string, because of the specific sonority created by an open string.
+
+Double stopping is when two separate strings are stopped by the fingers, and bowed simultaneously, producing a sixth, third, fifth, etc. Double-stops can be indicated in any position, though the widest interval that can be double-stopped in one position is an octave (with the first finger on the lower string and the fourth finger on the higher string). Nonetheless, intervals of tenths or even more are sometimes required to be double-stopped in advanced playing, resulting in a stretched left-hand position with the fingers extended. The term "double stop" is often used to encompass sounding an open string alongside a fingered note as well, even though only one finger stops the string.
+
+Where three or four more simultaneous notes are written, the violinist will typically "split" the chord, choosing the lower one or two notes to play first before promptly continuing onto the upper one or two notes. A "triple stop" with three simultaneous notes is possible in some circumstances. The bow will not naturally strike three strings at once, but if there is sufficient bow speed and pressure when the violinist "breaks" a three note chord, the bow hair can be bent  temporarily so all three can sound. This is accomplished with a heavy stroke, typically quite near the frog, and quite loud. Double stops in orchestra are occasionally marked divisi and divided between the players, with half of the musicians playing the lower note and the other half playing the higher note.. Playing double stops is common when the violins play accompaniment and another instrument or section plays melodically.
+
+In some genres of historically informed performance (usually of Baroque music and earlier), neither split-chord nor triple-stop chords are thought to be appropriate and violinists will arpeggiate all chords (and even what appear to be regular double stops), playing all or most notes individually as if they had been written as a slurred figure. In some musical styles, a sustained open string drone can be played during a passage mainly written on an adjacent string, to provide a basic accompaniment. This is more often seen in folk traditions than in classical music. However, with the development of modern violins, triple-stopping came more naturally due to the bridge being less curved.
+
+Vibrato is a technique of the left hand and arm in which the pitch of a note varies subtly in a pulsating rhythm. While various parts of the hand or arm may be involved in the motion, the end result is a movement of the fingertip bringing about a slight change in vibrating string length, which causes an undulation in pitch. Some violinists oscillate backwards, or lower in pitch from the actual note when using vibrato, since it is believed that perception favors the highest pitch in a varying sound.[31] Vibrato does little, if anything, to disguise an out-of-tune note; in other words, misapplied vibrato is a poor substitute for good intonation. Scales and other exercises meant to work on intonation are typically played without vibrato to make the work easier and more effective. Music students are often taught that unless otherwise marked in music, vibrato is assumed. However, it has to be noted that this is only a trend; there is nothing on the sheet music that compels violinists to add vibrato. This can be an obstacle to a classically trained violinist wishing to play in a style that uses little or no vibrato at all, such as baroque music played in period style and many traditional fiddling styles.
+
+Vibrato can be produced by a proper combination of finger, wrist and arm motions. One method, called hand vibrato, involves rocking the hand back at the wrist to achieve oscillation, while another method, arm vibrato, modulates the pitch by rocking at the elbow. A combination of these techniques allows a player to produce a large variety of tonal effects. The "when" and "what for" and "how much" of violin vibrato are artistic matters of style and taste. Different teachers, music schools and styles of music favour different vibrato styles. For example, overdone vibrato may become distracting. In acoustic terms, the interest that vibrato adds to the sound has to do with the way that the overtone mix[32] (or tone color, or timbre) and the directional pattern of sound projection change with changes in pitch. By "pointing" the sound at different parts of the room[33][34] in a rhythmic way, vibrato adds a "shimmer" or "liveliness" to the sound of a well-made violin. Vibrato is, in a large part, left to the discretion of the violinist.  Different types of vibrato will bring different moods to the piece, and the varying degrees and styles of vibrato are often characteristics that stand out in well-known violinists.
+
+A vibrato-like motion can sometimes be used to create a fast trill effect. To execute this effect, the finger above the finger stopping the note is placed very slightly off the string (firmly pressed against the finger stopping the string) and a vibrato motion is implemented. The second finger will lightly touch the string above the lower finger with each oscillation, causing the pitch to oscillate in a fashion that sounds like a mix between vide vibrato and a very fast trill. This gives a less defined transition between the higher and lower note, and is usually implemented by interpretative choice. This trill technique only works well for semi-tonal trills or trills in high positions (where the distance between notes is lessened), as it requires the trilling finger and the finger below it to be touching, limiting the distance that can be trilled. In very high positions, where the trilled distance is less than the width of the finger, a vibrato trill may be the only option for trill effects.
+
+A major scale (arco and pizzicato)
+Beginning of an A major scale with vibrato
+A major scale played col legno
+Natural harmonics of an A, E, and an A
+Artificial (false) harmonic of A7
+
+Lightly touching the string with a fingertip at a harmonic node, but without fully pressing the string, and then plucking or bowing the string, creates harmonics. Instead of the normal tone, a higher pitched note sounds.  Each node is at an integer division of the string, for example half-way or one-third along the length of the string. A responsive instrument will sound numerous possible harmonic nodes along the length of the string. Harmonics are marked in music either with a little circle above the note that determines the pitch of the harmonic, or by diamond-shaped note heads. There are two types of harmonics: natural harmonics and artificial harmonics (also known as false harmonics).
+
+Natural harmonics are played on an open string. The pitch of the open string when it is plucked or bowed is called the fundamental frequency.  Harmonics are also called overtones or partials. They occur at whole-number multiples of the fundamental, which is called the first harmonic.  The second harmonic is the first overtone (the octave above the open string), the third harmonic is the second overtone, and so on. The second harmonic is in the middle of the string and sounds an octave higher than the string's pitch.  The third harmonic breaks the string into thirds and sounds an octave and a fifth above the fundamental, and the fourth harmonic breaks the string into quarters sounding two octaves above the first. The sound of the second harmonic is the clearest of them all, because it is a common node with all the succeeding even-numbered harmonics (4th, 6th, etc.). The third and succeeding odd-numbered harmonics are harder to play because they break the string into an odd number of vibrating parts and do not share as many nodes with other harmonics.
+
+Artificial harmonics are more difficult to produce than natural harmonics, as they involve both stopping the string and playing a harmonic on the stopped note. Using the octave frame (the normal distance between the first and fourth fingers in any given position) with the fourth finger just touching the string a fourth higher than the stopped note produces the fourth harmonic, two octaves above the stopped note. Finger placement and pressure, as well as bow speed, pressure, and sounding point are all essential in getting the desired harmonic to sound. And to add to the challenge, in passages with different notes played as false harmonics, the distance between stopping finger and harmonic finger must constantly change, since the spacing between notes changes along the length of the string.
+
+The harmonic finger can also touch at a major third above the pressed note (the fifth harmonic), or a fifth higher (a third harmonic).  These harmonics are less commonly used; in the case of the major third, both the stopped note and touched note must be played slightly sharp otherwise the harmonic does not speak as readily.  In the case of the fifth, the stretch is greater than is comfortable for many violinists. In the general repertoire fractions smaller than a sixth are not used.  However, divisions up to an eighth are sometimes used and, given a good instrument and a skilled player, divisions as small as a twelfth are possible. There are a few books dedicated solely to the study of violin harmonics. Two comprehensive works are Henryk Heller's seven-volume Theory of Harmonics, published by Simrock in 1928, and Michelangelo Abbado's five-volume Tecnica dei suoni armonici published by Ricordi in 1934.
+
+Elaborate passages in artificial harmonics can be found in virtuoso violin literature, especially of the 19th and early 20th centuries. Two notable examples of this are an entire section of Vittorio Monti's Csárdás and a passage towards the middle of the third movement of Pyotr Ilyich Tchaikovsky's Violin Concerto. A section of the third movement of Paganini's Violin Concerto No. 1 consists of double-stopped thirds in harmonics.
+
+When strings are worn, dirty and old, the harmonics may no longer be accurate in pitch. For this reason, violinists change their strings regularly.
+
+The strings may be sounded by drawing the hair of the bow held by the right hand across them (arco) or by plucking them (pizzicato) most often with the right hand. In some cases, the violinist will pluck strings with the left hand. This is done to facilitate transitions from pizzicato to arco playing. It is also used in some virtuoso showpieces. Left hand pizzicato is usually done on open strings. Pizzicato is used on all of the violin family instruments; however, the systematic study of advanced pizzicato techniques is most developed in jazz bass, a style in which the instrument is almost exclusively plucked.
+
+The right arm, hand, and bow and the bow speed are responsible for tone quality, rhythm, dynamics, articulation, and most (but not all) changes in timbre. The player draws the bow over the string, causing the string to vibrate and produce a sustained tone. The bow is a wooden stick with tensioned horsetail hair, which has been rosined with a bar of rosin. The natural texture of the horsehair and the stickiness of the rosin help the bow to "grip" the string, and thus when the bow is drawn over the string, the bow causes the string to sound a pitch.
+
+Bowing can be used to produce long sustained notes or melodies. With a string section, if the players in a section change their bows at different times, a note can seem to be endlessly sustainable. As well, the bow can be used to play short, crisp little notes, such as repeated notes, scales and arpeggios, which provide a propulsive rhythm in many styles of music.
+
+The most essential part of bowing technique is the bow grip. It is usually with the thumb bent in the small area between the frog and the winding of the bow. The other fingers are spread somewhat evenly across the top part of the bow. The pinky finger is curled with the tip of the finger placed on the wood next to the screw. The violin produces louder notes with greater bow speed or more weight on the string.  The two methods are not equivalent, because they produce different timbres; pressing down on the string tends to produce a harsher, more intense sound. One can also achieve a louder sound by placing the bow closer to the bridge.
+
+The sounding point where the bow intersects the string also influences timbre (or "tone colour"). Playing close to the bridge (sul ponticello) gives a more intense sound than usual, emphasizing the higher harmonics; and playing with the bow over the end of the fingerboard (sul tasto) makes for a delicate, ethereal sound, emphasizing the fundamental frequency. Dr. Suzuki referred to the sounding point as the Kreisler highway; one may think of different sounding points as lanes in the highway.
+
+Various methods of attack with the bow produce different articulations. There are many bowing techniques that allow for every range of playing style and many teachers, players, and orchestras spend a lot of time developing techniques and creating a unified technique within the group. These techniques include legato-style bowing (a smooth, connected, sustained sound suitable for melodies), collé, and a variety of bowings which produce shorter notes, including ricochet, sautillé, martelé, spiccato, and staccato.
+
+A note marked pizz. (abbreviation for pizzicato) in the written music is to be played by plucking the string with a finger of the right hand rather than by bowing. (The index finger is most commonly used here.) Sometimes in orchestra parts or virtuoso solo music where the bow hand is occupied (or for show-off effect), left-hand pizzicato will be indicated by a + (plus sign) below or above the note.  In left-hand pizzicato, two fingers are put on the string; one (usually the index or middle finger) is put on the correct note, and the other (usually the ring finger or little finger) is put above the note. The higher finger then plucks the string while the lower one stays on, thus producing the correct pitch. By increasing the force of the pluck, one can increase the volume of the note that the string is producing. Pizzicato is used in orchestral works and in solo showpieces. In orchestral parts, violinists often have to make very quick shifts from arco to pizzicato, and vice versa.
+
+A marking of col legno (Italian for "with the wood") in the written music calls for striking the string(s) with the stick of the bow, rather than by drawing the hair of the bow across the strings.  This bowing technique is somewhat rarely used, and results in a muted percussive sound. The eerie quality of a violin section playing col legno is exploited in some symphonic pieces, notably the "Witches' Dance" of the last movement of Berlioz's Symphonie Fantastique. Saint-Saëns's symphonic poem Danse Macabre includes the string section using the col legno technique to imitate the sound of dancing skeletons. "Mars" from Gustav Holst's "The Planets" uses col legno to play a repeated rhythm in 54 time signature. Benjamin Britten's The Young Person's Guide to the Orchestra demands its use in the "Percussion" Variation. Dmitri Shostakovich uses it in his Fourteenth Symphony in the movement 'At the Sante Jail'. Some violinists, however, object to this style of playing as it can damage the finish and impair the value of a fine bow, but most of such will compromise by using a cheap bow for at least the duration of the passage in question.
+
+A smooth and even stroke during which bow speed and weight are the same from beginning of the stroke to the end.[35]
+
+Literally hammered, a strongly accented effect produced by releasing each bowstroke forcefully and suddenly. Martelé can be played in any part of the bow. It is sometimes indicated in written music by an arrowhead.
+
+Tremolo is the very rapid repetition (typically of a single note, but occasionally of multiple notes), usually played at the tip of the bow. Tremolo is marked with three short, slanted lines across the stem of the note. Tremolo is often used as a sound effect in orchestral music, particularly in the Romantic music era (1800-1910) and in opera music.
+
+Attaching a small metal, rubber, leather, or wooden device called a mute, or sordino, to the bridge of the violin gives a softer, more mellow tone, with fewer audible overtones; the sound of an entire orchestral string section playing with mutes has a hushed quality. The mute changes both the loudness and the timbre ("tone colour") of a violin. The conventional Italian markings for mute usage are con sord., or con sordino, meaning 'with mute'; and senza sord., meaning 'without mute'; or via sord., meaning 'mute off'.
+
+Larger metal, rubber, or wooden mutes are widely available, known as practice mutes or hotel mutes.  Such mutes are generally not used in performance, but are used to deaden the sound of the violin in practice areas such as hotel rooms. (For practicing purposes there is also the mute violin, a violin without a sound box.) Some composers have used practice mutes for special effect, for example, at the end of Luciano Berio's Sequenza VIII for solo violin.
+
+Since the Baroque era, the violin has been one of the most important of all instruments in classical music, for several reasons.  The tone of the violin stands out above other instruments, making it appropriate for playing a melody line.  In the hands of a good player, the violin is extremely agile, and can execute rapid and difficult sequences of notes.
+
+Violins make up a large part of an orchestra, and are usually divided into two sections, known as the first and second violins. Composers often assign the melody to the first violins, typically a more difficult part using higher positions, while second violins play harmony, accompaniment patterns or the melody an octave lower than the first violins. A string quartet similarly has parts for first and second violins, as well as a viola part, and a bass instrument, such as the cello or, rarely, the double bass.
+
+The earliest references to jazz performance using the violin as a solo instrument are documented during the first decades of the 20th century. Joe Venuti, one of the first jazz violinists, is known for his work with guitarist Eddie Lang during the 1920s. Since that time there have been many improvising violinists including Stéphane Grappelli, Stuff Smith, Eddie South, Regina Carter, Johnny Frigo, John Blake, Adam Taubitz, Leroy Jenkins, and Jean-Luc Ponty. While not primarily jazz violinists, Darol Anger and Mark O'Connor have spent significant parts of their careers playing jazz.
+The Swiss-Cuban violinist Yilian Cañizares mixes jazz with Cuban music.[36]
+
+Violins also appear in ensembles supplying orchestral backgrounds to many jazz recordings.
+
+The Indian violin, while essentially the same instrument as that used in Western music, is different in some senses.[37] The instrument is tuned so that the IV and III strings (G and D on a western-tuned violin) and the II and I (A and E) strings are sa–pa (do–sol) pairs and sound the same but are offset by an octave, resembling common scordatura or fiddle cross-tunings such as G–D–G–D or A–E–A–E. The tonic sa (do) is not fixed, but variably tuned to accommodate the vocalist or lead player. The way the musician holds the instrument varies from Western to Indian music. In Indian music the musician sits on the floor cross-legged with the right foot out in front of them. The scroll of the instrument rests on the foot. This position is essential to playing well due to the nature of Indian music. The hand can move all over the fingerboard and there is no set position for the left hand, so it is important for the violin to be in a steady, unmoving position.
+
+Up through at least the 1970s, most types of popular music used bowed string sections. They were extensively used in popular music throughout the 1920s and early 1930s. With the rise of swing music, however, from 1935 to 1945, the string sound was often used to add to the fullness of big band music. Following the swing era, from the late 1940s to the mid-1950s, strings began to be revived in traditional pop music. This trend accelerated in the late 1960s, with a significant revival of the use of strings, especially in soul music. Popular Motown recordings of the late 1960s and 1970s relied heavily on strings as part of their trademark texture. The rise of disco music in the 1970s continued this trend with the heavy use of string instruments in popular disco orchestras (e.g., Love Unlimited Orchestra, Biddu Orchestra, Monster Orchestra, Salsoul Orchestra, MFSB).[citation needed]
+
+With the rise of electronically created music in the 1980s, violins declined in use, as synthesized string sounds played by a keyboardist with a synthesizer took their place. However, while the violin has had very little usage in mainstream rock music, it has some history in progressive rock (e.g., Electric Light Orchestra, King Crimson, Kansas, Gentle Giant). The 1973 album Contaminazione by Italy's RDM plays violins off against synthesizers at its finale ("La grande fuga").[citation needed] The instrument has a stronger place in modern jazz fusion bands, notably The Corrs.  The fiddle is sometimes a part of British folk rock music, as exemplified by the likes of Fairport Convention and Steeleye Span.[citation needed]
+
+The popularity of crossover music beginning in the last years of the 20th century has brought the violin back into the popular music arena, with both electric and acoustic violins being used by popular bands. Dave Matthews Band features violinist Boyd Tinsley.  The Flock featured violinist Jerry Goodman who later joined the jazz-rock fusion band, The Mahavishnu Orchestra.  James' Saul Davies, who is also a guitarist, was enlisted by the band as a violinist. For their first three albums and related singles, the British group No-Man made extensive use of electric and acoustic solo violin as played by band member Ben Coleman (who played violin exclusively).[citation needed]
+
+Pop-Punk band Yellowcard has made a mainstay of violin in its music. Violinist Sean Mackin has been a member of the band since 1997. Los Salvadores also combine punk and ska influences with a violin.[citation needed] Doom metal band My Dying Bride have used violin as a part of their line-up throughout many of their albums.[citation needed] The violin appears prominently in the music of Spanish folk metal group Mägo de Oz (for example, in their 1998 hit "Molinos de viento"). The violinist (Carlos Prieto a.k.a. "Mohamed") has been one of the group's most popular members with fans since 1992.[citation needed] The instrument is also used often in symphonic metal, particularly by bands such as Therion, Nightwish, Within Temptation, Haggard, and Epica, although it can also be found in Gothic Metal bands such as Tristania and Theater of Tragedy.[citation needed] The alternative rock band Hurt's vocalist plays violin for the band, making them one of few rock bands to feature violin without hiring a session worker.[citation needed] The folk metal band Ithilien use violin extensively along their discography.[38] Progressive metal band Ne Obliviscaris feature a violin player, Tim Charles, in their line-up.[39]
+
+Independent artists, such as Owen Pallett, The Shondes, and Andrew Bird, have also spurred increased interest in the instrument.[40] Indie bands have often embraced new and unusual arrangements, allowing them more freedom to feature the violin than many mainstream musical artists.  It has been used in the post-rock genre by bands such as A Genuine Freakshow, Sigur Rós, Zox, Broken Social Scene, and A Silver Mt. Zion. The electric violin has even been used by bands like The Crüxshadows within the context of keyboard based music.[citation needed] Lindsey Stirling plays the violin in conjunction with electronic/dubstep/trance rifts and beats.[41][citation needed]
+
+Eric Stanley improvises on the violin with hip hop music/pop/classical elements and instrumental beats.[42][43] The successful indie rock and baroque pop band Arcade Fire use violins extensively in their arrangements.[44] Indian, Turkish, and Arabic pop music is filled with the sound of violins, both soloists and ensembles.[citation needed]
+
+Like many other instruments used in classical music, the violin descends from remote ancestors that were used for folk music.  Following a stage of intensive development in the late Renaissance, largely in Italy, the violin had improved (in volume, tone, and agility), to the point that it not only became a very important instrument in art music, but proved highly appealing to folk musicians as well, ultimately spreading very widely, sometimes displacing earlier bowed instruments. Ethnomusicologists have observed its widespread use in Europe, Asia, and the Americas.
+
+When played as a folk instrument, the violin is usually referred to in English as a fiddle (although the term fiddle can be used informally no matter what the genre of music). Worldwide, there are various stringed instruments such as the wheel fiddle and Apache fiddle that are also called "fiddles". Fiddle music differs from classical in that the tunes are generally considered dance music,[45] and various techniques, such as droning, shuffling, and ornamentation specific to particular styles are used. In many traditions of folk music, the tunes are not written but are memorized by successive generations of musicians and passed on[45] in what is known as the oral tradition. Many old-time pieces call for cross-tuning, or using tunings other than standard GDAE. Some players of American styles of folk fiddling (such as bluegrass or old-time) have their bridge's top edge cut to a slightly flatter curve, making techniques such as a "double shuffle" less taxing on the bow arm, as it reduces the range of motion needed for alternating between double stops on different string pairs. Fiddlers who use solid steel core strings may prefer to use a tailpiece with fine tuners on all four strings, instead of the single fine tuner on the E string used by many classical players.
+
+As well as the Arabic rababah, the violin has been used in Arabic music.
+
+Electric violins have a magnetic or piezoelectric pickup that converts string vibration to an electric signal. A patch cable or wireless transmitter sends the signal to an amplifier of a PA system. Electric violins are usually constructed as such, but a pickup can be added to a conventional acoustic violin. An electric violin with a resonating body that produces listening-level sound independently of the electric elements can be called an electro-acoustic violin. To be effective as an acoustic violin, electro-acoustic violins retain much of the resonating body of the violin, and often resemble an acoustic violin or fiddle.  The body may be finished in bright colors and made from alternative materials to wood. These violins may need to be hooked up to an instrument amplifier or PA system.  Some types come with a silent option that allows the player to use headphones that are hooked up to the violin. The first specially built electric violins date back to 1928 and were made by Victor Pfeil, Oskar Vierling, George Eisenberg, Benjamin Miessner, George Beauchamp, Hugo Benioff and Fredray Kislingbury. These violins can be plugged into effect units, just like an electric guitar, including distortion, wah-wah pedal and reverb. Since electric violins do not rely on string tension and resonance to amplify their sound they can have more strings. For example, five-stringed electric violins are available from several manufacturers, and a seven string electric violin (with three lower strings encompassing the cello's range) is also available.[46] The majority of the first electric violinists were musicians playing jazz fusion (e.g., Jean-Luc Ponty) and popular music.
+
+Violin authentication is the process of determining the maker and manufacture date of a violin. This process is similar to that used to determine the provenance of art works.  As significant value may be attached to violins made either by specific makers or at specific times and locations, forgery and other methods of fraudulent misrepresentation can be used to inflate the value of an instrument.

en/5998.html.txt

@@ -0,0 +1,230 @@
+
+
+Violence is "the use of physical force so as to injure, abuse, damage, or destroy"[2]. Less conventional definitions are also used, such as the World Health Organization's definition of violence as "the intentional use of physical force or power, threatened[3] or actual, against oneself, another person, or against a group or community, which either results in or has a high likelihood of resulting in injury, death, psychological harm, maldevelopment, or deprivation."[4]
+
+Internationally, violence resulted in deaths of an estimated 1.28 million people in 2013 up from 1.13 million in 1990.[5] Of the deaths in 2013, roughly 842,000 were attributed to self-harm (suicide), 405,000 to interpersonal violence, and 31,000 to collective violence (war) and legal intervention.[5] For each single death due to violence, there are dozens of hospitalizations, hundreds of emergency department visits, and thousands of doctors' appointments.[6] Furthermore, violence often has lifelong consequences for physical and mental health and social functioning and can slow economic and social development.
+
+In 2013, of the estimated 405,000 deaths due to interpersonal violence globally, assault by firearm was the cause in 180,000 deaths, assault by sharp object was the cause in 114,000 deaths, and the remaining 110,000 deaths from other causes.[5]
+
+Violence in many forms can be preventable. There is a strong relationship between levels of violence and modifiable factors in a country such as an concentrated (regional) poverty, income and gender inequality, the harmful use of alcohol, and the absence of safe, stable, and nurturing relationships between children and parents. Strategies addressing the underlying causes of violence can be relatively effective in preventing violence, although mental and physical health and individual responses, personalities, etc. have always been decisive factors in the formation of these behaviors.[7]
+
+The World Health Organization divides violence into three broad categories:[4]
+
+This initial categorization differentiates between violence a person inflicts upon himself or herself, violence inflicted by another individual or by a small group of individuals, and violence inflicted by larger groups such as states, organized political groups, militia groups and terrorist organizations. These three broad categories are each divided further to reflect more specific types of violence:
+
+Alternatively, violence can primarily be classified as either instrumental or reactive / hostile.[8]
+
+Self-directed violence is subdivided into suicidal behaviour and self-abuse. The former includes suicidal thoughts, attempted suicides – also called para suicide or deliberate self-injury in some countries – and completed suicides. Self-abuse, in contrast, includes acts such as self-mutilation.
+
+Collective violence is subdivided into structural violence and economic violence. Unlike the other two broad categories, the subcategories of collective violence suggest possible motives for violence committed by larger groups of individuals or by states. Collective violence that is committed to advance a particular social agenda includes, for example, crimes of hate committed by organized groups, terrorist acts and mob violence. Political violence includes war and related violent conflicts, state violence and similar acts carried out by larger groups. Economic violence includes attacks by larger groups motivated by economic gain – such as attacks carried out with the purpose of disrupting economic activity, denying access to essential services, or creating economic division and fragmentation. Clearly, acts committed by larger groups can have multiple motives.[9]
+
+This typology, while imperfect and far from being universally accepted, does provide a useful framework for understanding the complex patterns of violence taking place around the world, as well as violence in the everyday lives of individuals, families and communities. It also overcomes many of the limitations of other typologies by capturing the nature of violent acts, the relevance of the setting, the relationship between the perpetrator and the victim, and – in the case of collective violence – possible motivations for the violence. However, in both research and practice, the dividing lines between the different types of violence are not always so clear.[citation needed] State violence also involves upholding, forms of violence of a structural nature, such as poverty, through dismantling welfare, creating strict policies such as 'welfare to work', in order to cause further stimulation and disadvantage[9] Poverty as a form of violence may involve oppressive policies that specifically target minority or low socio-economic groups. The 'war on drugs', for example, rather than increasing the health and well-being of at risk demographics, most often results in violence committed against these vulnerable demographics through incarceration, stigmatization and police brutality[9][10]
+
+War is a state of prolonged violent large-scale conflict involving two or more groups of people, usually under the auspices of government. It is the most extreme form of collective violence.[11]
+War is fought as a means of resolving territorial and other conflicts, as war of aggression to conquer territory or loot resources, in national self-defence or liberation, or to suppress attempts of part of the nation to secede from it. There are also ideological, religious and revolutionary wars.[12]
+
+Since the Industrial Revolution the lethality of modern warfare has grown. World War I casualties were over 40 million and World War II casualties were over 70 million.
+
+Interpersonal violence is divided into two subcategories: Family and intimate partner violence – that is, violence largely between family members and intimate partners, usually, though not exclusively, taking place in the home. Community violence – violence between individuals who are unrelated, and who may or may not know each other, generally taking place outside the home. The former group includes forms of violence such as child abuse, intimate partner violence and abuse of the elderly. The latter includes youth violence, random acts of violence, rape or sexual assault by strangers, and violence in institutional settings such as schools, workplaces, prisons and nursing homes. When interpersonal violence occurs in families, its psychological consequences can affect parents, children, and their relationship in the short- and long-terms.[13]
+
+Child maltreatment is the abuse and neglect that occurs to children under 18 years of age. It includes all types of physical and/or emotional ill-treatment, sexual abuse, neglect, negligence and commercial or other child exploitation, which results in actual or potential harm to the child's health, survival, development or dignity in the context of a relationship of responsibility, trust, or power. Exposure to intimate partner violence is also sometimes included as a form of child maltreatment.[14]
+
+Child maltreatment is a global problem with serious lifelong consequences, which is, however, complex and difficult to study.[15]
+
+There are no reliable global estimates for the prevalence of child maltreatment. Data for many countries, especially low- and middle-income countries, are lacking. Current estimates vary widely depending on the country and the method of research used. Approximately 20% of women and 5–10% of men report being sexually abused as children, while 25–50% of all children report being physically abused.[4][16]
+
+Consequences of child maltreatment include impaired lifelong physical and mental health, and social and occupational functioning (e.g. school, job, and relationship difficulties). These can ultimately slow a country's economic and social development.[17][18] Preventing child maltreatment before it starts is possible and requires a multisectoral approach. Effective prevention programmes support parents and teach positive parenting skills. Ongoing care of children and families can reduce the risk of maltreatment reoccurring and can minimize its consequences.[19][20]
+
+Following the World Health Organization, youth are defined as people between the ages of 10 and 29 years. Youth violence refers to violence occurring between youths, and includes acts that range from bullying and physical fighting, through more severe sexual and physical assault to homicide.[21][22]
+
+Worldwide some 250,000 homicides occur among youth 10–29 years of age each year, which is 41% of the total number of homicides globally each year ("Global Burden of Disease", World Health Organization, 2008). For each young person killed, 20-40 more sustain injuries requiring hospital treatment.[21] Youth violence has a serious, often lifelong, impact on a person's psychological and social functioning. Youth violence greatly increases the costs of health, welfare and criminal justice services; reduces productivity; decreases the value of property; and generally undermines the fabric of society.[vague]
+
+Prevention programmes shown to be effective or to have promise in reducing youth violence include life skills and social development programmes designed to help children and adolescents manage anger, resolve conflict, and develop the necessary social skills to solve problems; schools-based anti-bullying prevention programmes; and programmes to reduce access to alcohol, illegal drugs and guns.[23] Also, given significant neighbourhood effects on youth violence, interventions involving relocating families to less poor environments have shown promising results.[24] Similarly, urban renewal projects such as business improvement districts have shown a reduction in youth violence.[25]
+
+Different types of youth on youth violence include witnessing or being involved in physical, emotional and sexual abuse (e.g. physical attacks, bullying, rape), and violent acts like gang shootings and robberies. According to researchers in 2018, "More than half of children and adolescents living in cities have experienced some form of community violence." The violence "can also all take place under one roof, or in a given community or neighborhood and can happen at the same time or at different stages of life."[26] Youth violence has immediate and long term adverse impact whether the individual was the recipient of the violence or a witness to it.[27]
+
+Youth violence impacts individuals, their families, and society. Victims can have lifelong injuries which means ongoing doctor and hospital visits, the cost of which quickly add up. Since the victims of youth-on-youth violence may not be able to attend school or work because of their physical and/or mental injuries, it is often up to their family members to take care of them, including paying their daily living expenses and medical bills. Their caretakers may have to give up their jobs or work reduced hours to provide help to the victim of violence. This causes a further burden on society because the victim and maybe even their caretakers have to obtain government assistance to help pay their bills. Recent research has found that psychological trauma during childhood can change a child's brain. "Trauma is known to physically affect the brain and the body which causes anxiety, rage, and the ability to concentrate. They can also have problems remembering, trusting, and forming relationships."[28] Since the brain becomes used to violence it may stay continually in an alert state (similar to being stuck in the fight or flight mode). "Researchers claim that the youth who are exposed to violence may have emotional, social, and cognitive problems. They may have trouble controlling emotions, paying attention in school, withdraw from friends, or show signs of post-traumatic stress disorder".[26]
+
+It is important for youth exposed to violence to understand how their bodies may react so they can take positive steps to counteract any possible short- and long-term negative effects (e.g., poor concentration, feelings of depression, heightened levels of anxiety). By taking immediate steps to mitigate the effects of the trauma they've experienced, negative repercussions can be reduced or eliminated. As an initial step, the youths need to understand why they may be feeling a certain way and to understand how the violence they have experienced may be causing negative feelings and making them behave differently. Pursuing a greater awareness of their feelings, perceptions, and negative emotions is the first step that should be taken as part of recovering from the trauma they have experienced. “Neuroscience research shows that the only way we can change the way we feel is by becoming aware of our inner experience and learning to befriend what is going on inside ourselves”.[29]
+
+Some of the ways to combat the adverse effects of exposure to youth violence would be to try various mindfulness and movement activities, deep breathing exercises and other actions that enable youths to release their pent up emotions. Using these techniques will teach body awareness, reduce anxiety and nervousness, and reduce feelings of anger and annoyance.[30] Over time these types of activities will help these younger victims of violence to have greater control over their feelings and behaviors and avoid unhealthy ways of coping. Another way to help trauma victims of youth violence is through the arts. This can be accomplished by giving them the opportunity to engage in drawing, painting, music, and singing which will give them an outlet to express themselves and their emotions in a positive way.[31]
+
+Youth who have experienced violence benefit from having a close relationship with one or more people.[29] This is important because the trauma victims need to have people who are safe and trustworthy that they can relate and talk to about their horrible experiences. Some youth do not have adult figures at home or someone they can count on for guidance and comfort. Schools in bad neighborhoods where youth violence is prevalent should assign counselors to each student so that they receive regular guidance. In addition to counseling/therapy sessions and programs, it has been recommended that schools offer mentoring programs where students can interact with adults who can be a positive influence on them. Another way is to create more neighborhood programs to ensure that each child has a positive and stable place to go when school in not in session. Many children have benefited from formal organizations now which aim to help mentor and provide a safe environment for the youth especially those living in neighborhoods with higher rates of violence. This includes organizations such as Becoming a Man, CeaseFire Illinois, Chicago Area Project, Little Black Pearl, and Rainbow House".[32] These programs are designed to help give the youth a safe place to go, stop the violence from occurring, offering counseling and mentoring to help stop the cycle of violence. If the youth do not have a safe place to go after school hours they will likely get into trouble, receive poor grades, drop out of school and use drugs and alcohol. The gangs look for youth who do not have positive influences in their life and need protection. This is why these programs are so important for the youth to have a safe environment rather than resorting to the streets.[33]
+
+Intimate partner violence refers to behaviour in an intimate relationship that causes physical, sexual or psychological harm, including physical aggression, sexual coercion, psychological abuse and controlling behaviours.[4]
+
+Population-level surveys based on reports from victims provide the most accurate estimates of the prevalence of intimate partner violence and sexual violence in non-conflict settings. A study conducted by WHO in 10 mainly developing countries[34] found that, among women aged 15 to 49 years, between 15% (Japan) and 70% (Ethiopia and Peru) of women reported physical and/or sexual violence by an intimate partner.
+
+Intimate partner and sexual violence have serious short- and long-term physical, mental, sexual and reproductive health problems for victims and for their children, and lead to high social and economic costs. These include both fatal and non-fatal injuries, depression and post-traumatic stress disorder, unintended pregnancies, sexually transmitted infections, including HIV.[35]
+
+Factors associated with the perpetration and experiencing of intimate partner violence are low levels of education, history of violence as a perpetrator, a victim or a witness of parental violence, harmful use of alcohol, attitudes that are accepting of violence as well as marital discord and dissatisfaction. Factors associated only with perpetration of intimate partner violence are having multiple partners, and antisocial personality disorder.
+
+A recent theory named "The Criminal Spin" suggests a mutual flywheel effect between partners that is manifested by an escalation in the violence.[36] A violent spin may occur in any other forms of violence, but in Intimate partner violence the added value is the mutual spin, based on the unique situation and characteristics of intimate relationship.
+
+The primary prevention strategy with the best evidence for effectiveness for intimate partner violence is school-based programming for adolescents to prevent violence within dating relationships.[37] Evidence is emerging for the effectiveness of several other primary prevention strategies – those that: combine microfinance with gender equality training;[38] promote communication and relationship skills within communities; reduce access to, and the harmful use of alcohol; and change cultural gender norms.[39]
+
+Sexual violence is any sexual act, attempt to obtain a sexual act, unwanted sexual comments or advances, or acts to traffic, or otherwise directed against a person's sexuality using coercion, by any person regardless of their relationship to the victim, in any setting. It includes rape, defined as the physically forced or otherwise coerced penetration of the vulva or anus with a penis, other body part or object.[40]
+
+Population-level surveys based on reports from victims estimate that between 0.3–11.5% of women reported experiencing sexual violence.[41] Sexual violence has serious short- and long-term consequences on physical, mental, sexual and reproductive health for victims and for their children as described in the section on intimate partner violence. If perpetrated during childhood, sexual violence can lead to increased smoking,[42] drug and alcohol misuse, and risky sexual behaviors in later life. It is also associated with perpetration of violence and being a victim of violence.
+
+Many of the risk factors for sexual violence are the same as for domestic violence. Risk factors specific to sexual violence perpetration include beliefs in family honor and sexual purity, ideologies of male sexual entitlement and weak legal sanctions for sexual violence.
+
+Few interventions to prevent sexual violence have been demonstrated to be effective. School-based programmes to prevent child sexual abuse by teaching children to recognize and avoid potentially sexually abusive situations are run in many parts of the world and appear promising, but require further research. To achieve lasting change, it is important to enact legislation and develop policies that protect women; address discrimination against women and promote gender equality; and help to move the culture away from violence.[39]
+
+Elder maltreatment is a single or repeated act, or lack of appropriate action, occurring within any relationship where there is an expectation of trust which causes harm or distress to an older person. This type of violence constitutes a violation of human rights and includes physical, sexual, psychological, emotional; financial and material abuse; abandonment; neglect; and serious loss of dignity and respect.[4]
+
+While there is little information regarding the extent of maltreatment in elderly populations, especially in developing countries, it is estimated that 4–6% of elderly people in high-income countries have experienced some form of maltreatment at home[43][44] However, older people are often afraid to report cases of maltreatment to family, friends, or to the authorities. Data on the extent of the problem in institutions such as hospitals, nursing homes and other long-term care facilities are scarce. Elder maltreatment can lead to serious physical injuries and long-term psychological consequences. Elder maltreatment is predicted to increase as many countries are experiencing rapidly ageing populations.
+
+Many strategies have been implemented to prevent elder maltreatment and to take action against it and mitigate its consequences including public and professional awareness campaigns, screening (of potential victims and abusers), caregiver support interventions (e.g. stress management, respite care), adult protective services and self-help groups. Their effectiveness has, however, not so far been well-established.[45][46]
+
+Several rare but painful episodes of assassination, attempted assassination and school shootings at elementary, middle, high schools, as well as colleges and universities in the United States, led to a considerable body of research on ascertainable behaviors of persons who have planned or carried out such attacks. These studies (1995–2002) investigated what the authors called "targeted violence," described the "path to violence" of those who planned or carried out attacks and laid out suggestions for law enforcement and educators. A major point from these research studies is that targeted violence does not just "come out of the blue".[47][48][49][50][51][52]
+
+As an anthropological concept, "everyday violence" may refer to the incorporation of different forms of violence (mainly political violence) into daily practices.[53][54][55] Latin America and the Caribbean, the region with the highest murder rate in the world,[56] experienced more than 2.5 million murders between 2000 and 2017.[57]
+
+Violence cannot be attributed to a single factor. Its causes are complex and occur at different levels. To represent this complexity, the ecological, or social ecological model is often used. The following four-level version of the ecological model is often used in the study of violence:
+
+The first level identifies biological and personal factors that influence how individuals behave and increase their likelihood of becoming a victim or perpetrator of violence: demographic characteristics (age, education, income), genetics, brain lesions, personality disorders, substance abuse, and a history of experiencing, witnessing, or engaging in violent behaviour.[58][59]
+
+The second level focuses on close relationships, such as those with family and friends. In youth violence, for example, having friends who engage in or encourage violence can increase a young person's risk of being a victim or perpetrator of violence. For intimate partner violence, a consistent marker at this level of the model is marital conflict or discord in the relationship. In elder abuse, important factors are stress due to the nature of the past relationship between the abused person and the care giver.
+
+The third level explores the community context—i.e., schools, workplaces, and neighbourhoods. Risk at this level may be affected by factors such as the existence of a local drug trade, the absence of social networks, and concentrated poverty. All these factors have been shown to be important in several types of violence.
+
+Finally, the fourth level looks at the broad societal factors that help to create a climate in which violence is encouraged or inhibited: the responsiveness of the criminal justice system, social and cultural norms regarding gender roles or parent-child relationships, income inequality, the strength of the social welfare system, the social acceptability of violence, the availability of weapons, the exposure to violence in mass media, and political instability.
+
+While studies showing associations between physical punishment of children and later aggression cannot prove that physical punishment causes an increase in aggression, a number of longitudinal studies suggest that the experience of physical punishment has a direct causal effect on later aggressive behaviors.[60] Cross-cultural studies have shown that greater prevalence of corporal punishment of children tends to predict higher levels of violence in societies. For instance, a 2005 analysis of 186 pre-industrial societies found that corporal punishment was more prevalent in societies which also had higher rates of homicide, assault, and war.[61] In the United States, domestic corporal punishment has been linked to later violent acts against family members and spouses.[62] The American family violence researcher Murray A. Straus believes that disciplinary spanking forms "the most prevalent and important form of violence in American families", whose effects contribute to several major societal problems, including later domestic violence and crime.[63]
+
+The causes of violent behavior in people are often a topic of research in psychology. Neurobiologist Jan Vodka emphasizes that, for those purposes, "violent behavior is defined as overt and intentional physically aggressive behavior against another person."[64]
+
+Based on the idea of human nature, scientists do agree violence is inherent in humans. Among prehistoric humans, there is archaeological evidence for both contentions of violence and peacefulness as primary characteristics.[65]
+
+Since violence is a matter of perception as well as a measurable phenomenon, psychologists have found variability in whether people perceive certain physical acts as "violent". For example, in a state where execution is a legalized punishment we do not typically perceive the executioner as "violent", though we may talk, in a more metaphorical way, of the state acting violently. Likewise, understandings of violence are linked to a perceived aggressor-victim relationship: hence psychologists have shown that people may not recognise defensive use of force as violent, even in cases where the amount of force used is significantly greater than in the original aggression.[66]
+
+In an article entitled "The History of Violence" in The New Republic, Steven Pinker posits that, on average, the amount and cruelty of violence to humans and animals has decreased over the last few centuries.[67]
+
+Pinker's observation of the decline in interpersonal violence echoes the work of Norbert Elias, who attributes the decline to a "civilizing process", in which the state's monopolization of violence, the maintenance of socioeconomic interdependencies or "figurations", and the maintenance of behavioural codes in culture all contribute to the development of individual sensibilities, which increase the repugnance of individuals towards violent acts.[68]
+
+Some scholars disagree with the argument that all violence is decreasing arguing that not all types of violent behaviour are lower now than in the past. They suggest that research typically focuses on lethal violence, often looks at homicide rates of death due to warfare, but ignore the less obvious forms of violence.[69] However, non-lethal violence, such as assaults or bullying appear to be declining as well.[70]
+In his article "The Coming Anarchy", Robert D. Kaplan introduces the notion of liberating violence. According to Kaplan, we will observe more violent civil wars in the future, which will be fought due to economic inequalities around the world.[71]
+
+The concept of violence normalization, is known as socially sanctioned or structural violence, and is a topic of increasing interest to researchers trying to understand violent behavior. It has been discussed at length by researchers in sociology,[72][73] medical anthropology,[74][75] psychology,[76] philosophy,[77] and bioarchaeology.[78][79]
+
+Evolutionary psychology offers several explanations for human violence in various contexts, such as sexual jealousy in humans,[80] child abuse,[81] and homicide.[82] Goetz (2010) argues that humans are similar to most mammal species and use violence in specific situations. He writes that "Buss and Shackelford (1997a) proposed seven adaptive problems our ancestors recurrently faced that might have been solved by aggression: co-opting the resources of others, defending against attack, inflicting costs on same-sex rivals, negotiating status and hierarchies, deterring rivals from future aggression, deterring mate from infidelity, and reducing resources expended on genetically unrelated children."[83]
+
+Goetz writes that most homicides seem to start from relatively trivial disputes between unrelated men who then escalate to violence and death. He argues that such conflicts occur when there is a status dispute between men of relatively similar status. If there is a great initial status difference, then the lower status individual usually offers no challenge and if challenged the higher status individual usually ignores the lower status individual. At the same an environment of great inequalities between people may cause those at the bottom to use more violence in attempts to gain status.[83]
+
+Research into the media and violence examines whether links between consuming media violence and subsequent aggressive and violent behaviour exists. Although some scholars had claimed media violence may increase aggression,[84] this view is coming increasingly in doubt both in the scholarly community[85] and was rejected by the US Supreme Court in the Brown v EMA case, as well as in a review of video game violence by the Australian Government (2010) which concluded evidence for harmful effects were inconclusive at best and the rhetoric of some scholars was not matched by good data.
+
+The threat and enforcement of physical punishment has been a tried and tested method of preventing some violence since civilisation began.[86] It is used in various degrees in most countries.
+
+A review of scientific literature by the World Health Organization on the effectiveness of strategies to prevent interpersonal violence identified the seven strategies below as being supported by either strong or emerging evidence for effectiveness.[87] These strategies target risk factors at all four levels of the ecological model.
+
+Among the most effective such programmes to prevent child maltreatment and reduce childhood aggression are the Nurse Family Partnership home-visiting programme[88] and the Triple P (Parenting Program).[89] There is also emerging evidence that these programmes reduce convictions and violent acts in adolescence and early adulthood, and probably help decrease intimate partner violence and self-directed violence in later life.[90][91]
+
+Evidence shows that the life skills acquired in social development programmes can reduce involvement in violence, improve social skills, boost educational achievement and improve job prospects. Life skills refer to social, emotional, and behavioural competencies which help children and adolescents effectively deal with the challenges of everyday life.
+
+Evaluation studies are beginning to support community interventions that aim to prevent violence against women by promoting gender equality. For instance, evidence suggests that programmes that combine microfinance with gender equity training can reduce intimate partner violence.[92][93] School-based programmes such as Safe Dates programme in the United States of America[94][95] and the Youth Relationship Project in Canada[96] have been found to be effective for reducing dating violence.
+
+Rules or expectations of behaviour – norms – within a cultural or social group can encourage violence. Interventions that challenge cultural and social norms supportive of violence can prevent acts of violence and have been widely used, but the evidence base for their effectiveness is currently weak. The effectiveness of interventions addressing dating violence and sexual abuse among teenagers and young adults by challenging social and cultural norms related to gender is supported by some evidence.[97][98]
+
+Interventions to identify victims of interpersonal violence and provide effective care and support are critical for protecting health and breaking cycles of violence from one generation to the next. Examples for which evidence of effectiveness is emerging includes: screening tools to identify victims of intimate partner violence and refer them to appropriate services;[99] psychosocial interventions – such as trauma-focused cognitive behavioural therapy – to reduce mental health problems associated with violence, including post-traumatic stress disorder;[100] and protection orders, which prohibit a perpetrator from contacting the victim,[101][102] to reduce repeat victimization among victims of intimate partner violence.
+
+Not surprisingly, scientific evidence about the effectiveness of interventions to prevent collective violence is lacking.[103] However, policies that facilitate reductions in poverty, that make decision-making more accountable, that reduce inequalities between groups, as well as policies that reduce access to biological, chemical, nuclear and other weapons have been recommended. When planning responses to violent conflicts, recommended approaches include assessing at an early stage who is most vulnerable and what their needs are, co-ordination of activities between various players and working towards global, national and local capabilities so as to deliver effective health services during the various stages of an emergency.[104]
+
+One of the main functions of law is to regulate violence.[105] Sociologist Max Weber stated that the state claims the monopoly of the legitimate use of force practised within the confines of a specific territory. Law enforcement is the main means of regulating nonmilitary violence in society. Governments regulate the use of violence through legal systems governing individuals and political authorities, including the police and military. Civil societies authorize some amount of violence, exercised through the police power, to maintain the status quo and enforce laws.
+
+However, German political theorist Hannah Arendt noted: "Violence can be justifiable, but it never will be legitimate ... Its justification loses in plausibility the farther its intended end recedes into the future. No one questions the use of violence in self-defence, because the danger is not only clear but also present, and the end justifying the means is immediate".[106] Arendt made a clear distinction between violence and power. Most political theorists regarded violence as an extreme manifestation of power whereas Arendt regarded the two concepts as opposites.[107]
+In the 20th century in acts of democide governments may have killed more than 260 million of their own people through police brutality, execution, massacre, slave labour camps, and sometimes through intentional famine.[108][109]
+
+Violent acts that are not carried out by the military or police and that are not in self-defense are usually classified as crimes, although not all crimes are violent crimes. Damage to property is classified as violent crime in some jurisdictions but not in all.[citation needed] The Federal Bureau of Investigation (FBI) classifies violence resulting in homicide into criminal homicide and justifiable homicide (e.g. self-defense).[110]
+
+The criminal justice approach sees its main task as enforcing laws that proscribe violence and ensuring that "justice is done". The notions of individual blame, responsibility, guilt, and culpability are central to criminal justice's approach to violence and one of the criminal justice system's main tasks is to "do justice", i.e. to ensure that offenders are properly identified, that the degree of their guilt is as accurately ascertained as possible, and that they are punished appropriately. To prevent and respond to violence, the criminal justice approach relies primarily on deterrence, incarceration and the punishment and rehabilitation of perpetrators.[111]
+
+The criminal justice approach, beyond justice and punishment, has traditionally emphasized indicated interventions, aimed at those who have already been involved in violence, either as victims or as perpetrators. One of the main reasons offenders are arrested, prosecuted, and convicted is to prevent further crimes – through deterrence (threatening potential offenders with criminal sanctions if they commit crimes), incapacitation (physically preventing offenders from committing further crimes by locking them up) and through rehabilitation (using time spent under state supervision to develop skills or change one's psychological make-up to reduce the likelihood of future offences).[112]
+
+In recent decades in many countries in the world, the criminal justice system has taken an increasing interest in preventing violence before it occurs. For instance, much of community and problem-oriented policing aims to reduce crime and violence by altering the conditions that foster it – and not to increase the number of arrests. Indeed, some police leaders have gone so far as to say the police should primarily be a crime prevention agency.[113] Juvenile justice systems – an important component of criminal justice systems – are largely based on the belief in rehabilitation and prevention. In the US, the criminal justice system has, for instance, funded school- and community-based initiatives to reduce children's access to guns and teach conflict resolution. In 1974, the US Department of Justice assumed primary responsibility for delinquency prevention programmes and created the Office of Juvenile Justice and Delinquency Prevention, which has supported the "Blueprints for violence prevention" programme at the University of Colorado Boulder.[114]
+
+The public health approach is a science-driven, population-based, interdisciplinary, intersectoral approach based on the ecological model which emphasizes primary prevention.[4] Rather than focusing on individuals, the public health approach aims to provide the maximum benefit for the largest number of people, and to extend better care and safety to entire populations. The public health approach is interdisciplinary, drawing upon knowledge from many disciplines including medicine, epidemiology, sociology, psychology, criminology, education and economics. Because all forms of violence are multi-faceted problems, the public health approach emphasizes a multi-sectoral response. It has been proved time and again that cooperative efforts from such diverse sectors as health, education, social welfare, and criminal justice are often necessary to solve what are usually assumed to be purely "criminal" or "medical" problems. The public health approach considers that violence, rather than being the result of any single factor, is the outcome of multiple risk factors and causes, interacting at four levels of a nested hierarchy (individual, close relationship/family, community and wider society) of the Social ecological model.
+
+From a public health perspective, prevention strategies can be classified into three types:
+
+A public health approach emphasizes the primary prevention of violence, i.e. stopping them from occurring in the first place. Until recently, this approach has been relatively neglected in the field, with the majority of resources directed towards secondary or tertiary prevention. Perhaps the most critical element of a public health approach to prevention is the ability to identify underlying causes rather than focusing upon more visible "symptoms". This allows for the development and testing of effective approaches to address the underlying causes and so improve health.
+
+The public health approach is an evidence-based and systematic process involving the following four steps:
+
+In many countries, violence prevention is still a new or emerging field in public health. The public health community has started only recently to realize the contributions it can make to reducing violence and mitigating its consequences. In 1949, Gordon called for injury prevention efforts to be based on the understanding of causes, in a similar way to prevention efforts for communicable and other diseases.[115] In 1962, Gomez, referring to the WHO definition of health, stated that it is obvious that violence does not contribute to "extending life" or to a "complete state of well-being". He defined violence as an issue that public health experts needed to address and stated that it should not be the primary domain of lawyers, military personnel, or politicians.[116]
+
+However, it is only in the last 30 years that public health has begun to address violence, and only in the last fifteen has it done so at the global level.[117] This is a much shorter period of time than public health has been tackling other health problems of comparable magnitude and with similarly severe lifelong consequences.
+
+The global public health response to interpersonal violence began in earnest in the mid-1990s. In 1996, the World Health Assembly adopted Resolution WHA49.25[118] which declared violence "a leading worldwide public health problem" and requested that the World Health Organization (WHO) initiate public health activities to (1) document and characterize the burden of violence, (2) assess the effectiveness of programmes, with particular attention to women and children and community-based initiatives, and (3) promote activities to tackle the problem at the international and national levels. The World Health Organization's initial response to this resolution was to create the Department of Violence and Injury Prevention and Disability and to publish the World report on violence and health (2002).[4]
+
+The case for the public health sector addressing interpersonal violence rests on four main arguments.[119] First, the significant amount of time health care professionals dedicate to caring for victims and perpetrators of violence has made them familiar with the problem and has led many, particularly in emergency departments, to mobilize to address it. The information, resources, and infrastructures the health care sector has at its disposal are an important asset for research and prevention work. Second, the magnitude of the problem and its potentially severe lifelong consequences and high costs to individuals and wider society call for population-level interventions typical of the public health approach. Third, the criminal justice approach, the other main approach to addressing violence (link to entry above), has traditionally been more geared towards violence that occurs between male youths and adults in the street and other public places – which makes up the bulk of homicides in most countries – than towards violence occurring in private settings such as child maltreatment, intimate partner violence and elder abuse – which makes up the largest share of non-fatal violence. Fourth, evidence is beginning to accumulate that a science-based public health approach is effective at preventing interpersonal violence.
+
+The human rights approach is based on the obligations of states to respect, protect and fulfill human rights and therefore to prevent, eradicate and punish violence. It recognizes violence as a violation of many human rights: the rights to life, liberty, autonomy and security of the person; the rights to equality and non-discrimination; the rights to be free from torture and cruel, inhuman and degrading treatment or punishment; the right to privacy; and the right to the highest attainable standard of health. These human rights are enshrined in international and regional treaties and national constitutions and laws, which stipulate the obligations of states, and include mechanisms to hold states accountable. The Convention on the Elimination of All Forms of Discrimination Against Women, for example, requires that countries party to the Convention take all appropriate steps to end violence against women. The Convention on the Rights of the Child in its Article 19 states that States Parties shall take all appropriate legislative, administrative, social and educational measures to protect the child from all forms of physical or mental violence, injury or abuse, neglect or negligent treatment, maltreatment or exploitation, including sexual abuse, while in the care of parent(s), legal guardian(s) or any other person who has the care of the child.
+
+Violence, as defined in the dictionary of human geography, "appears whenever power is in jeopardy" and "in and of itself stands emptied of strength and purpose: it is part of a larger matrix of socio-political power struggles".[120] Violence can be broadly divided into three broad categories – direct violence, structural violence and cultural violence.[120] Thus defined and delineated, it is of note, as Hyndman says, that "geography came late to theorizing violence"[120] in comparison to other social sciences. Social and human geography, rooted in the humanist, Marxist, and feminist subfields that emerged following the early positivist approaches and subsequent behavioral turn, have long been concerned with social and spatial justice.[121]
+Along with critical geographers and political geographers, it is these groupings of geographers that most often interact with violence. Keeping this idea of social/spatial justice via geography in mind, it is worthwhile to look at geographical approaches to violence in the context of politics.
+
+Derek Gregory and Alan Pred assembled the influential edited collection Violent Geographies: Fear, Terror, and Political Violence, which demonstrates how place, space, and landscape are foremost factors in the real and imagined practices of organized violence both historically and in the present.[122] Evidently, political violence often gives a part for the state to play. When "modern states not only claim a monopoly of the legitimate means of violence; they also routinely use the threat of violence to enforce the rule of law",[120] the law not only becomes a form of violence but is violence.[120] Philosopher Giorgio Agamben's concepts of state of exception and homo sacer are useful to consider within a geography of violence. The state, in the grip of a perceived, potential crisis (whether legitimate or not) takes preventative legal measures, such as a suspension of rights (it is in this climate, as Agamben demonstrates, that the formation of the Social Democratic and Nazi government's lager or concentration camp can occur). However, when this "in limbo" reality is designed to be in place "until further notice…the state of exception thus ceases to be referred to as an external and provisional state of factual danger and comes to be confused with juridical rule itself".[123] For Agamben, the physical space of the camp "is a piece of land placed outside the normal juridical order, but it is nevertheless not simply an external space".[123] At the scale of the body, in the state of exception, a person is so removed from their rights by "juridical procedures and deployments of power"[123] that "no act committed against them could appear any longer as a crime";[123] in other words, people become only homo sacer. Guantanamo Bay could also be said to represent the physicality of the state of exception in space, and can just as easily draw man as homo sacer.
+
+In the 1970s, genocides in Cambodia under the Khmer Rouge and Pol Pot resulted in the deaths of over two million Cambodians (which was 25% of the Cambodian population), forming one of the many contemporary examples of state-sponsored violence.[124] About fourteen thousand of these murders occurred at Choeung Ek, which is the best-known of the extermination camps referred to as the Killing Fields.[124] The killings were arbitrary; for example, a person could be killed for wearing glasses, since that was seen as associating them with intellectuals and therefore as making them part of the enemy. People were murdered with impunity because it was no crime; Cambodians were made homo sacer in a condition of bare life. The Killing Fields—manifestations of Agamben's concept of camps beyond the normal rule of law—featured the state of exception. As part of Pol Pot's "ideological intent…to create a purely agrarian society or cooperative",[124] he "dismantled the country's existing economic infrastructure and depopulated every urban area".[124] Forced movement, such as this forced movement applied by Pol Pot, is a clear display of structural violence. When "symbols of Cambodian society were equally disrupted, social institutions of every kind…were purged or torn down",[124] cultural violence (defined as when "any aspect of culture such as language, religion, ideology, art, or cosmology is used to legitimize direct or structural violence"[120]) is added to the structural violence of forced movement and to the direct violence, such as murder, at the Killing Fields. Vietnam eventually intervened and the genocide officially ended. However, ten million landmines left by opposing guerillas in the 1970s[124] continue to create a violent landscape in Cambodia.
+
+Human geography, though coming late to the theorizing table, has tackled violence through many lenses, including anarchist geography, feminist geography, Marxist geography, political geography, and critical geography. However, Adriana Cavarero notes that, "as violence spreads and assumes unheard-of forms, it becomes difficult to name in contemporary language".[125] Cavarero proposes that, in facing such a truth, it is prudent to reconsider violence as "horrorism"; that is, "as though ideally all the…victims, instead of their killers, ought to determine the name".[125] With geography often adding the forgotten spatial aspect to theories of social science, rather than creating them solely within the discipline, it seems that the self-reflexive contemporary geography of today may have an extremely important place in this current (re)imaging of violence, exemplified by Cavarero.[clarification needed]
+
+As of 2010, all forms of violence resulted in about 1.34 million deaths up from about 1 million in 1990.[126] Suicide accounts for about 883,000, interpersonal violence for 456,000 and collective violence for 18,000.[126] Deaths due to collective violence have decreased from 64,000 in 1990.[126]
+
+By way of comparison, the 1.5 millions deaths a year due to violence is greater than the number of deaths due to tuberculosis (1.34 million), road traffic injuries (1.21 million), and malaria (830'000), but slightly less than the number of people who die from HIV/AIDS (1.77 million).[127]
+
+For every death due to violence, there are numerous nonfatal injuries. In 2008, over 16 million cases of non-fatal violence-related injuries were severe enough to require medical attention. Beyond deaths and injuries, forms of violence such as child maltreatment, intimate partner violence, and elder maltreatment have been found to be highly prevalent.
+
+In the last 45 years, suicide rates have increased by 60% worldwide.[citation needed] Suicide is among the three leading causes of death among those aged 15–44 years in some countries, and the second leading cause of death in the 10–24 years age group.[128] These figures do not include suicide attempts which are up to 20 times more frequent than completed suicide.[citation needed] Suicide was the 16th leading cause of death worldwide in 2004 and is projected to increase to the 12th in 2030.[129] Although suicide rates have traditionally been highest among the male elderly, rates among young people have been increasing to such an extent that they are now the group at highest risk in a third of countries, in both developed and developing countries.[citation needed]
+
+Rates and patterns of violent death vary by country and region. In recent years, homicide rates have been highest in developing countries in Sub-Saharan Africa and Latin America and the Caribbean and lowest in East Asia, the western Pacific, and some countries in northern Africa.[130] Studies show a strong, inverse relationship between homicide rates and both economic development and economic equality. Poorer countries, especially those with large gaps between the rich and the poor, tend to have higher rates of homicide than wealthier countries. Homicide rates differ markedly by age and sex. Gender differences are least marked for children. For the 15 to 29 age group, male rates were nearly six times those for female rates; for the remaining age groups, male rates were from two to four times those for females.[131]
+
+Studies in a number of countries show that, for every homicide among young people age 10 to 24, 20 to 40 other young people receive hospital treatment for a violent injury.[4]
+
+Forms of violence such as child maltreatment and intimate partner violence are highly prevalent. Approximately 20% of women and 5–10% of men report being sexually abused as children, while 25–50% of all children report being physically abused.[132] A WHO multi-country study found that between 15–71% of women reported experiencing physical and/or sexual violence by an intimate partner at some point in their lives.[133]
+
+Wars grab headlines, but the individual risk of dying violently in an armed conflict is today relatively low—much lower than the risk of violent death in many countries that are not suffering from an armed conflict. For example, between 1976 and 2008, African Americans were victims of 329,825 homicides.[134][135] Although there is a widespread perception that war is the most dangerous form of armed violence in the world, the average person living in a conflict-affected country had a risk of dying violently in the conflict of about 2.0 per 100,000 population between 2004 and 2007. This can be compared to the average world homicide rate of 7.6 per 100,000 people. This illustration highlights the value of accounting for all forms of armed violence rather than an exclusive focus on conflict related violence. Certainly, there are huge variations in the risk of dying from armed conflict at the national and subnational level, and the risk of dying violently in a conflict in specific countries remains extremely high. In Iraq, for example, the direct conflict death rate for 2004–07 was 65 per 100,000 people per year and, in Somalia, 24 per 100,000 people. This rate even reached peaks of 91 per 100,000 in Iraq in 2006 and 74 per 100,000 in Somalia in 2007.[136]
+
+Scientific evidence for warfare has come from settled, sedentary communities.[137] Some scholars argue humans may have a predisposition for violence (chimpanzees, also great apes, have been known to kill members of competing groups for resources like food),[137] placing the origins of organized violence prior to modern settled societies.[138][137] However, actual evidence suggests that organized, large-scale, militaristic, or regular human-on-human violence was absent for the vast majority of the human timeline,[139][140][141] and is first documented to have started only relatively recently in the Holocene, an epoch that began about 11,700 years ago, probably with the advent of higher population densities due to sedentism.[140] Social anthropologist Douglas P. Fry writes that scholars are divided on the origins of this greater degree of violence—in other words, war-like behavior:
+
+There are basically two schools of thought on this issue. One holds that warfare... goes back at least to the time of the first thoroughly modern humans and even before then to the primate ancestors of the hominid lineage. The second positions on the origins of warfare sees war as much less common in the cultural and biological evolution of humans. Here, warfare is a latecomer on the cultural horizon, only arising in very specific material circumstances and being quite rare in human history until the development of agriculture in the past 10,000 years.[142]
+
+Jared Diamond in his books Guns, Germs and Steel and The Third Chimpanzee posits that the rise of large-scale warfare is the result of advances in technology and city-states. For instance, the rise of agriculture provided a significant increase in the number of individuals that a region could sustain over hunter-gatherer societies, allowing for development of specialized classes such as soldiers, or weapons manufacturers.
+
+In academia, the idea of the peaceful pre-history and non-violent tribal societies gained popularity with the post-colonial perspective. The trend, starting in archaeology and spreading to anthropology reached its height in the late half of the 20th century.[143] However, some newer research in archaeology and bioarchaeology may provide evidence that violence within and among groups is not a recent phenomenon.[144][unreliable source?] According to the book "The Bioarchaeology of Violence" violence is a behavior that is found throughout human history.[145]
+
+Lawrence H. Keeley at the University of Illinois writes in War Before Civilization that 87% of tribal societies were at war more than once per year, and that 65% of them were fighting continuously. He writes that the attrition rate of numerous close-quarter clashes, which characterize endemic warfare, produces casualty rates of up to 60%, compared to 1% of the combatants as is typical in modern warfare. "Primitive Warfare" of these small groups or tribes was driven by the basic need for sustenance and violent competition.[146]
+
+Fry explores Keeley's argument in depth and counters that such sources erroneously focus on the ethnography of hunters and gatherers in the present, whose culture and values have been infiltrated externally by modern civilization, rather than the actual archaeological record spanning some two million years of human existence. Fry determines that all present ethnographically studied tribal societies, "by the very fact of having been described and published by anthropologists, have been irrevocably impacted by history and modern colonial nation states" and that "many have been affected by state societies for at least 5000 years."[147]
+
+The relatively peaceful period since World War II is known as the Long Peace.
+
+Steven Pinker's 2011 book, The Better Angels of Our Nature, roused both acclaim and controversy by asserting that modern society is less violent than in periods of the past, whether on the short scale of decades or long scale of centuries or millennia.
+
+Steven Pinker argues that by every possible measure, every type of violence has drastically decreased since ancient and medieval times. A few centuries ago, for example, genocide was a standard practice in all kinds of warfare and was so common that historians did not even bother to mention it. Cannibalism and slavery have been greatly reduced in the last thousand years, and capital punishment is now banned in many countries. According to Pinker, rape, murder, warfare and animal cruelty have all seen drastic declines in the 20th century.[148] However, Pinker's analyses have met with much criticism, mainly concerning the statistical question of how to measure violence and whether it is in fact declining.[149][150][151]
+
+Beyond deaths and injuries, highly prevalent forms of violence (such as child maltreatment and intimate partner violence) have serious lifelong non-injury health consequences. Victims may engage in high-risk behaviours such as alcohol and substance misuse and smoking, which in turn can contribute to cardiovascular disorders, cancers, depression, diabetes and HIV/AIDS, resulting in premature death.[152] The balances of prevention, mitigation, mediation and exacerbation are complex, and vary with the underpinnings of violence.
+
+In countries with high levels of violence, economic growth can be slowed down, personal and collective security eroded, and social development impeded. Families edging out of poverty and investing in schooling their sons and daughters can be ruined through the violent death or severe disability of the main breadwinner. Communities can be caught in poverty traps where pervasive violence and deprivation form a vicious circle that stifles economic growth. For societies, meeting the direct costs of health, criminal justice, and social welfare responses to violence diverts many billions of dollars from more constructive societal spending. The much larger indirect costs of violence due to lost productivity and lost investment in education work together to slow economic development, increase socioeconomic inequality, and erode human and social capital.
+
+Additionally, communities with high level of violence do not provide the level of stability and predictability vital for a prospering business economy. Individuals will be less likely to invest money and effort towards growth in such unstable and violent conditions. One of the possible proves might be the study of Baten and Gust that used “regicide” as measurement unit to approximate the influence of interpersonal violence and depict the influence of high interpersonal violence on economic development and level of investments. The results of the research prove the correlation of the human capital and the interpersonal violence.[153]
+
+In 2016, the Institute for Economics and Peace, released the Economic Value of Peace report, which estimates the economic impact of violence and conflict on the global economy, the total economic impact of violence on the world economy in 2015 was estimated to be $13.6 trillion[154] in purchasing power parity terms.
+
+Religious and political ideologies have been the cause of interpersonal violence throughout history.[155] Ideologues often falsely accuse others of violence, such as the ancient blood libel against Jews, the medieval accusations of casting witchcraft spells against women, and modern accusations of satanic ritual abuse against day care center owners and others.[156]
+
+Both supporters and opponents of the 21st-century War on Terrorism regard it largely as an ideological and religious war.[157]
+
+Vittorio Bufacchi describes two different modern concepts of violence, one the "minimalist conception" of violence as an intentional act of excessive or destructive force, the other the "comprehensive conception" which includes violations of rights, including a long list of human needs.[158]
+
+Anti-capitalists assert that capitalism is violent. They believe private property and profit survive only because police violence defends them and that capitalist economies need war to expand.[159] They may use the term "structural violence" to describe the systematic ways in which a given social structure or institution kills people slowly by preventing them from meeting their basic needs, for example the deaths caused by diseases because of lack of medicine.[160]
+
+Frantz Fanon critiqued the violence of colonialism and wrote about the counter violence of the "colonized victims."[161][162][163]
+
+Throughout history, most religions and individuals like Mahatma Gandhi have preached that humans are capable of eliminating individual violence and organizing societies through purely nonviolent means. Gandhi himself once wrote: "A society organized and run on the basis of complete non-violence would be the purest anarchy."[164] Modern political ideologies which espouse similar views include pacifist varieties of voluntarism, mutualism, anarchism and libertarianism.
+
+Terence Fretheim writing about the Old Testament:
+
+For many people, ... only physical violence truly qualifies as violence. But, certainly, violence is more than killing people, unless one includes all those words and actions that kill people slowly. The effect of limitation to a “killing fields” perspective is the widespread neglect of many other forms of violence. We must insist that violence also refers to that which is psychologically destructive, that which demeans, damages, or depersonalizes others. In view of these considerations, violence may be defined as follows: any action, verbal or nonverbal, oral or written, physical or psychical, active or passive, public or private, individual or institutional/societal, human or divine, in whatever degree of intensity, that abuses, violates, injures, or kills. Some of the most pervasive and most dangerous forms of violence are those that are often hidden from view (against women and children, especially); just beneath the surface in many of our homes, churches, and communities is abuse enough to freeze the
+blood. Moreover, many forms of systemic violence often slip past our attention because they are so much a part of the infrastructure of life (e.g., racism, sexism, ageism).[165]

en/5999.html.txt

@@ -0,0 +1,230 @@
+
+
+Violence is "the use of physical force so as to injure, abuse, damage, or destroy"[2]. Less conventional definitions are also used, such as the World Health Organization's definition of violence as "the intentional use of physical force or power, threatened[3] or actual, against oneself, another person, or against a group or community, which either results in or has a high likelihood of resulting in injury, death, psychological harm, maldevelopment, or deprivation."[4]
+
+Internationally, violence resulted in deaths of an estimated 1.28 million people in 2013 up from 1.13 million in 1990.[5] Of the deaths in 2013, roughly 842,000 were attributed to self-harm (suicide), 405,000 to interpersonal violence, and 31,000 to collective violence (war) and legal intervention.[5] For each single death due to violence, there are dozens of hospitalizations, hundreds of emergency department visits, and thousands of doctors' appointments.[6] Furthermore, violence often has lifelong consequences for physical and mental health and social functioning and can slow economic and social development.
+
+In 2013, of the estimated 405,000 deaths due to interpersonal violence globally, assault by firearm was the cause in 180,000 deaths, assault by sharp object was the cause in 114,000 deaths, and the remaining 110,000 deaths from other causes.[5]
+
+Violence in many forms can be preventable. There is a strong relationship between levels of violence and modifiable factors in a country such as an concentrated (regional) poverty, income and gender inequality, the harmful use of alcohol, and the absence of safe, stable, and nurturing relationships between children and parents. Strategies addressing the underlying causes of violence can be relatively effective in preventing violence, although mental and physical health and individual responses, personalities, etc. have always been decisive factors in the formation of these behaviors.[7]
+
+The World Health Organization divides violence into three broad categories:[4]
+
+This initial categorization differentiates between violence a person inflicts upon himself or herself, violence inflicted by another individual or by a small group of individuals, and violence inflicted by larger groups such as states, organized political groups, militia groups and terrorist organizations. These three broad categories are each divided further to reflect more specific types of violence:
+
+Alternatively, violence can primarily be classified as either instrumental or reactive / hostile.[8]
+
+Self-directed violence is subdivided into suicidal behaviour and self-abuse. The former includes suicidal thoughts, attempted suicides – also called para suicide or deliberate self-injury in some countries – and completed suicides. Self-abuse, in contrast, includes acts such as self-mutilation.
+
+Collective violence is subdivided into structural violence and economic violence. Unlike the other two broad categories, the subcategories of collective violence suggest possible motives for violence committed by larger groups of individuals or by states. Collective violence that is committed to advance a particular social agenda includes, for example, crimes of hate committed by organized groups, terrorist acts and mob violence. Political violence includes war and related violent conflicts, state violence and similar acts carried out by larger groups. Economic violence includes attacks by larger groups motivated by economic gain – such as attacks carried out with the purpose of disrupting economic activity, denying access to essential services, or creating economic division and fragmentation. Clearly, acts committed by larger groups can have multiple motives.[9]
+
+This typology, while imperfect and far from being universally accepted, does provide a useful framework for understanding the complex patterns of violence taking place around the world, as well as violence in the everyday lives of individuals, families and communities. It also overcomes many of the limitations of other typologies by capturing the nature of violent acts, the relevance of the setting, the relationship between the perpetrator and the victim, and – in the case of collective violence – possible motivations for the violence. However, in both research and practice, the dividing lines between the different types of violence are not always so clear.[citation needed] State violence also involves upholding, forms of violence of a structural nature, such as poverty, through dismantling welfare, creating strict policies such as 'welfare to work', in order to cause further stimulation and disadvantage[9] Poverty as a form of violence may involve oppressive policies that specifically target minority or low socio-economic groups. The 'war on drugs', for example, rather than increasing the health and well-being of at risk demographics, most often results in violence committed against these vulnerable demographics through incarceration, stigmatization and police brutality[9][10]
+
+War is a state of prolonged violent large-scale conflict involving two or more groups of people, usually under the auspices of government. It is the most extreme form of collective violence.[11]
+War is fought as a means of resolving territorial and other conflicts, as war of aggression to conquer territory or loot resources, in national self-defence or liberation, or to suppress attempts of part of the nation to secede from it. There are also ideological, religious and revolutionary wars.[12]
+
+Since the Industrial Revolution the lethality of modern warfare has grown. World War I casualties were over 40 million and World War II casualties were over 70 million.
+
+Interpersonal violence is divided into two subcategories: Family and intimate partner violence – that is, violence largely between family members and intimate partners, usually, though not exclusively, taking place in the home. Community violence – violence between individuals who are unrelated, and who may or may not know each other, generally taking place outside the home. The former group includes forms of violence such as child abuse, intimate partner violence and abuse of the elderly. The latter includes youth violence, random acts of violence, rape or sexual assault by strangers, and violence in institutional settings such as schools, workplaces, prisons and nursing homes. When interpersonal violence occurs in families, its psychological consequences can affect parents, children, and their relationship in the short- and long-terms.[13]
+
+Child maltreatment is the abuse and neglect that occurs to children under 18 years of age. It includes all types of physical and/or emotional ill-treatment, sexual abuse, neglect, negligence and commercial or other child exploitation, which results in actual or potential harm to the child's health, survival, development or dignity in the context of a relationship of responsibility, trust, or power. Exposure to intimate partner violence is also sometimes included as a form of child maltreatment.[14]
+
+Child maltreatment is a global problem with serious lifelong consequences, which is, however, complex and difficult to study.[15]
+
+There are no reliable global estimates for the prevalence of child maltreatment. Data for many countries, especially low- and middle-income countries, are lacking. Current estimates vary widely depending on the country and the method of research used. Approximately 20% of women and 5–10% of men report being sexually abused as children, while 25–50% of all children report being physically abused.[4][16]
+
+Consequences of child maltreatment include impaired lifelong physical and mental health, and social and occupational functioning (e.g. school, job, and relationship difficulties). These can ultimately slow a country's economic and social development.[17][18] Preventing child maltreatment before it starts is possible and requires a multisectoral approach. Effective prevention programmes support parents and teach positive parenting skills. Ongoing care of children and families can reduce the risk of maltreatment reoccurring and can minimize its consequences.[19][20]
+
+Following the World Health Organization, youth are defined as people between the ages of 10 and 29 years. Youth violence refers to violence occurring between youths, and includes acts that range from bullying and physical fighting, through more severe sexual and physical assault to homicide.[21][22]
+
+Worldwide some 250,000 homicides occur among youth 10–29 years of age each year, which is 41% of the total number of homicides globally each year ("Global Burden of Disease", World Health Organization, 2008). For each young person killed, 20-40 more sustain injuries requiring hospital treatment.[21] Youth violence has a serious, often lifelong, impact on a person's psychological and social functioning. Youth violence greatly increases the costs of health, welfare and criminal justice services; reduces productivity; decreases the value of property; and generally undermines the fabric of society.[vague]
+
+Prevention programmes shown to be effective or to have promise in reducing youth violence include life skills and social development programmes designed to help children and adolescents manage anger, resolve conflict, and develop the necessary social skills to solve problems; schools-based anti-bullying prevention programmes; and programmes to reduce access to alcohol, illegal drugs and guns.[23] Also, given significant neighbourhood effects on youth violence, interventions involving relocating families to less poor environments have shown promising results.[24] Similarly, urban renewal projects such as business improvement districts have shown a reduction in youth violence.[25]
+
+Different types of youth on youth violence include witnessing or being involved in physical, emotional and sexual abuse (e.g. physical attacks, bullying, rape), and violent acts like gang shootings and robberies. According to researchers in 2018, "More than half of children and adolescents living in cities have experienced some form of community violence." The violence "can also all take place under one roof, or in a given community or neighborhood and can happen at the same time or at different stages of life."[26] Youth violence has immediate and long term adverse impact whether the individual was the recipient of the violence or a witness to it.[27]
+
+Youth violence impacts individuals, their families, and society. Victims can have lifelong injuries which means ongoing doctor and hospital visits, the cost of which quickly add up. Since the victims of youth-on-youth violence may not be able to attend school or work because of their physical and/or mental injuries, it is often up to their family members to take care of them, including paying their daily living expenses and medical bills. Their caretakers may have to give up their jobs or work reduced hours to provide help to the victim of violence. This causes a further burden on society because the victim and maybe even their caretakers have to obtain government assistance to help pay their bills. Recent research has found that psychological trauma during childhood can change a child's brain. "Trauma is known to physically affect the brain and the body which causes anxiety, rage, and the ability to concentrate. They can also have problems remembering, trusting, and forming relationships."[28] Since the brain becomes used to violence it may stay continually in an alert state (similar to being stuck in the fight or flight mode). "Researchers claim that the youth who are exposed to violence may have emotional, social, and cognitive problems. They may have trouble controlling emotions, paying attention in school, withdraw from friends, or show signs of post-traumatic stress disorder".[26]
+
+It is important for youth exposed to violence to understand how their bodies may react so they can take positive steps to counteract any possible short- and long-term negative effects (e.g., poor concentration, feelings of depression, heightened levels of anxiety). By taking immediate steps to mitigate the effects of the trauma they've experienced, negative repercussions can be reduced or eliminated. As an initial step, the youths need to understand why they may be feeling a certain way and to understand how the violence they have experienced may be causing negative feelings and making them behave differently. Pursuing a greater awareness of their feelings, perceptions, and negative emotions is the first step that should be taken as part of recovering from the trauma they have experienced. “Neuroscience research shows that the only way we can change the way we feel is by becoming aware of our inner experience and learning to befriend what is going on inside ourselves”.[29]
+
+Some of the ways to combat the adverse effects of exposure to youth violence would be to try various mindfulness and movement activities, deep breathing exercises and other actions that enable youths to release their pent up emotions. Using these techniques will teach body awareness, reduce anxiety and nervousness, and reduce feelings of anger and annoyance.[30] Over time these types of activities will help these younger victims of violence to have greater control over their feelings and behaviors and avoid unhealthy ways of coping. Another way to help trauma victims of youth violence is through the arts. This can be accomplished by giving them the opportunity to engage in drawing, painting, music, and singing which will give them an outlet to express themselves and their emotions in a positive way.[31]
+
+Youth who have experienced violence benefit from having a close relationship with one or more people.[29] This is important because the trauma victims need to have people who are safe and trustworthy that they can relate and talk to about their horrible experiences. Some youth do not have adult figures at home or someone they can count on for guidance and comfort. Schools in bad neighborhoods where youth violence is prevalent should assign counselors to each student so that they receive regular guidance. In addition to counseling/therapy sessions and programs, it has been recommended that schools offer mentoring programs where students can interact with adults who can be a positive influence on them. Another way is to create more neighborhood programs to ensure that each child has a positive and stable place to go when school in not in session. Many children have benefited from formal organizations now which aim to help mentor and provide a safe environment for the youth especially those living in neighborhoods with higher rates of violence. This includes organizations such as Becoming a Man, CeaseFire Illinois, Chicago Area Project, Little Black Pearl, and Rainbow House".[32] These programs are designed to help give the youth a safe place to go, stop the violence from occurring, offering counseling and mentoring to help stop the cycle of violence. If the youth do not have a safe place to go after school hours they will likely get into trouble, receive poor grades, drop out of school and use drugs and alcohol. The gangs look for youth who do not have positive influences in their life and need protection. This is why these programs are so important for the youth to have a safe environment rather than resorting to the streets.[33]
+
+Intimate partner violence refers to behaviour in an intimate relationship that causes physical, sexual or psychological harm, including physical aggression, sexual coercion, psychological abuse and controlling behaviours.[4]
+
+Population-level surveys based on reports from victims provide the most accurate estimates of the prevalence of intimate partner violence and sexual violence in non-conflict settings. A study conducted by WHO in 10 mainly developing countries[34] found that, among women aged 15 to 49 years, between 15% (Japan) and 70% (Ethiopia and Peru) of women reported physical and/or sexual violence by an intimate partner.
+
+Intimate partner and sexual violence have serious short- and long-term physical, mental, sexual and reproductive health problems for victims and for their children, and lead to high social and economic costs. These include both fatal and non-fatal injuries, depression and post-traumatic stress disorder, unintended pregnancies, sexually transmitted infections, including HIV.[35]
+
+Factors associated with the perpetration and experiencing of intimate partner violence are low levels of education, history of violence as a perpetrator, a victim or a witness of parental violence, harmful use of alcohol, attitudes that are accepting of violence as well as marital discord and dissatisfaction. Factors associated only with perpetration of intimate partner violence are having multiple partners, and antisocial personality disorder.
+
+A recent theory named "The Criminal Spin" suggests a mutual flywheel effect between partners that is manifested by an escalation in the violence.[36] A violent spin may occur in any other forms of violence, but in Intimate partner violence the added value is the mutual spin, based on the unique situation and characteristics of intimate relationship.
+
+The primary prevention strategy with the best evidence for effectiveness for intimate partner violence is school-based programming for adolescents to prevent violence within dating relationships.[37] Evidence is emerging for the effectiveness of several other primary prevention strategies – those that: combine microfinance with gender equality training;[38] promote communication and relationship skills within communities; reduce access to, and the harmful use of alcohol; and change cultural gender norms.[39]
+
+Sexual violence is any sexual act, attempt to obtain a sexual act, unwanted sexual comments or advances, or acts to traffic, or otherwise directed against a person's sexuality using coercion, by any person regardless of their relationship to the victim, in any setting. It includes rape, defined as the physically forced or otherwise coerced penetration of the vulva or anus with a penis, other body part or object.[40]
+
+Population-level surveys based on reports from victims estimate that between 0.3–11.5% of women reported experiencing sexual violence.[41] Sexual violence has serious short- and long-term consequences on physical, mental, sexual and reproductive health for victims and for their children as described in the section on intimate partner violence. If perpetrated during childhood, sexual violence can lead to increased smoking,[42] drug and alcohol misuse, and risky sexual behaviors in later life. It is also associated with perpetration of violence and being a victim of violence.
+
+Many of the risk factors for sexual violence are the same as for domestic violence. Risk factors specific to sexual violence perpetration include beliefs in family honor and sexual purity, ideologies of male sexual entitlement and weak legal sanctions for sexual violence.
+
+Few interventions to prevent sexual violence have been demonstrated to be effective. School-based programmes to prevent child sexual abuse by teaching children to recognize and avoid potentially sexually abusive situations are run in many parts of the world and appear promising, but require further research. To achieve lasting change, it is important to enact legislation and develop policies that protect women; address discrimination against women and promote gender equality; and help to move the culture away from violence.[39]
+
+Elder maltreatment is a single or repeated act, or lack of appropriate action, occurring within any relationship where there is an expectation of trust which causes harm or distress to an older person. This type of violence constitutes a violation of human rights and includes physical, sexual, psychological, emotional; financial and material abuse; abandonment; neglect; and serious loss of dignity and respect.[4]
+
+While there is little information regarding the extent of maltreatment in elderly populations, especially in developing countries, it is estimated that 4–6% of elderly people in high-income countries have experienced some form of maltreatment at home[43][44] However, older people are often afraid to report cases of maltreatment to family, friends, or to the authorities. Data on the extent of the problem in institutions such as hospitals, nursing homes and other long-term care facilities are scarce. Elder maltreatment can lead to serious physical injuries and long-term psychological consequences. Elder maltreatment is predicted to increase as many countries are experiencing rapidly ageing populations.
+
+Many strategies have been implemented to prevent elder maltreatment and to take action against it and mitigate its consequences including public and professional awareness campaigns, screening (of potential victims and abusers), caregiver support interventions (e.g. stress management, respite care), adult protective services and self-help groups. Their effectiveness has, however, not so far been well-established.[45][46]
+
+Several rare but painful episodes of assassination, attempted assassination and school shootings at elementary, middle, high schools, as well as colleges and universities in the United States, led to a considerable body of research on ascertainable behaviors of persons who have planned or carried out such attacks. These studies (1995–2002) investigated what the authors called "targeted violence," described the "path to violence" of those who planned or carried out attacks and laid out suggestions for law enforcement and educators. A major point from these research studies is that targeted violence does not just "come out of the blue".[47][48][49][50][51][52]
+
+As an anthropological concept, "everyday violence" may refer to the incorporation of different forms of violence (mainly political violence) into daily practices.[53][54][55] Latin America and the Caribbean, the region with the highest murder rate in the world,[56] experienced more than 2.5 million murders between 2000 and 2017.[57]
+
+Violence cannot be attributed to a single factor. Its causes are complex and occur at different levels. To represent this complexity, the ecological, or social ecological model is often used. The following four-level version of the ecological model is often used in the study of violence:
+
+The first level identifies biological and personal factors that influence how individuals behave and increase their likelihood of becoming a victim or perpetrator of violence: demographic characteristics (age, education, income), genetics, brain lesions, personality disorders, substance abuse, and a history of experiencing, witnessing, or engaging in violent behaviour.[58][59]
+
+The second level focuses on close relationships, such as those with family and friends. In youth violence, for example, having friends who engage in or encourage violence can increase a young person's risk of being a victim or perpetrator of violence. For intimate partner violence, a consistent marker at this level of the model is marital conflict or discord in the relationship. In elder abuse, important factors are stress due to the nature of the past relationship between the abused person and the care giver.
+
+The third level explores the community context—i.e., schools, workplaces, and neighbourhoods. Risk at this level may be affected by factors such as the existence of a local drug trade, the absence of social networks, and concentrated poverty. All these factors have been shown to be important in several types of violence.
+
+Finally, the fourth level looks at the broad societal factors that help to create a climate in which violence is encouraged or inhibited: the responsiveness of the criminal justice system, social and cultural norms regarding gender roles or parent-child relationships, income inequality, the strength of the social welfare system, the social acceptability of violence, the availability of weapons, the exposure to violence in mass media, and political instability.
+
+While studies showing associations between physical punishment of children and later aggression cannot prove that physical punishment causes an increase in aggression, a number of longitudinal studies suggest that the experience of physical punishment has a direct causal effect on later aggressive behaviors.[60] Cross-cultural studies have shown that greater prevalence of corporal punishment of children tends to predict higher levels of violence in societies. For instance, a 2005 analysis of 186 pre-industrial societies found that corporal punishment was more prevalent in societies which also had higher rates of homicide, assault, and war.[61] In the United States, domestic corporal punishment has been linked to later violent acts against family members and spouses.[62] The American family violence researcher Murray A. Straus believes that disciplinary spanking forms "the most prevalent and important form of violence in American families", whose effects contribute to several major societal problems, including later domestic violence and crime.[63]
+
+The causes of violent behavior in people are often a topic of research in psychology. Neurobiologist Jan Vodka emphasizes that, for those purposes, "violent behavior is defined as overt and intentional physically aggressive behavior against another person."[64]
+
+Based on the idea of human nature, scientists do agree violence is inherent in humans. Among prehistoric humans, there is archaeological evidence for both contentions of violence and peacefulness as primary characteristics.[65]
+
+Since violence is a matter of perception as well as a measurable phenomenon, psychologists have found variability in whether people perceive certain physical acts as "violent". For example, in a state where execution is a legalized punishment we do not typically perceive the executioner as "violent", though we may talk, in a more metaphorical way, of the state acting violently. Likewise, understandings of violence are linked to a perceived aggressor-victim relationship: hence psychologists have shown that people may not recognise defensive use of force as violent, even in cases where the amount of force used is significantly greater than in the original aggression.[66]
+
+In an article entitled "The History of Violence" in The New Republic, Steven Pinker posits that, on average, the amount and cruelty of violence to humans and animals has decreased over the last few centuries.[67]
+
+Pinker's observation of the decline in interpersonal violence echoes the work of Norbert Elias, who attributes the decline to a "civilizing process", in which the state's monopolization of violence, the maintenance of socioeconomic interdependencies or "figurations", and the maintenance of behavioural codes in culture all contribute to the development of individual sensibilities, which increase the repugnance of individuals towards violent acts.[68]
+
+Some scholars disagree with the argument that all violence is decreasing arguing that not all types of violent behaviour are lower now than in the past. They suggest that research typically focuses on lethal violence, often looks at homicide rates of death due to warfare, but ignore the less obvious forms of violence.[69] However, non-lethal violence, such as assaults or bullying appear to be declining as well.[70]
+In his article "The Coming Anarchy", Robert D. Kaplan introduces the notion of liberating violence. According to Kaplan, we will observe more violent civil wars in the future, which will be fought due to economic inequalities around the world.[71]
+
+The concept of violence normalization, is known as socially sanctioned or structural violence, and is a topic of increasing interest to researchers trying to understand violent behavior. It has been discussed at length by researchers in sociology,[72][73] medical anthropology,[74][75] psychology,[76] philosophy,[77] and bioarchaeology.[78][79]
+
+Evolutionary psychology offers several explanations for human violence in various contexts, such as sexual jealousy in humans,[80] child abuse,[81] and homicide.[82] Goetz (2010) argues that humans are similar to most mammal species and use violence in specific situations. He writes that "Buss and Shackelford (1997a) proposed seven adaptive problems our ancestors recurrently faced that might have been solved by aggression: co-opting the resources of others, defending against attack, inflicting costs on same-sex rivals, negotiating status and hierarchies, deterring rivals from future aggression, deterring mate from infidelity, and reducing resources expended on genetically unrelated children."[83]
+
+Goetz writes that most homicides seem to start from relatively trivial disputes between unrelated men who then escalate to violence and death. He argues that such conflicts occur when there is a status dispute between men of relatively similar status. If there is a great initial status difference, then the lower status individual usually offers no challenge and if challenged the higher status individual usually ignores the lower status individual. At the same an environment of great inequalities between people may cause those at the bottom to use more violence in attempts to gain status.[83]
+
+Research into the media and violence examines whether links between consuming media violence and subsequent aggressive and violent behaviour exists. Although some scholars had claimed media violence may increase aggression,[84] this view is coming increasingly in doubt both in the scholarly community[85] and was rejected by the US Supreme Court in the Brown v EMA case, as well as in a review of video game violence by the Australian Government (2010) which concluded evidence for harmful effects were inconclusive at best and the rhetoric of some scholars was not matched by good data.
+
+The threat and enforcement of physical punishment has been a tried and tested method of preventing some violence since civilisation began.[86] It is used in various degrees in most countries.
+
+A review of scientific literature by the World Health Organization on the effectiveness of strategies to prevent interpersonal violence identified the seven strategies below as being supported by either strong or emerging evidence for effectiveness.[87] These strategies target risk factors at all four levels of the ecological model.
+
+Among the most effective such programmes to prevent child maltreatment and reduce childhood aggression are the Nurse Family Partnership home-visiting programme[88] and the Triple P (Parenting Program).[89] There is also emerging evidence that these programmes reduce convictions and violent acts in adolescence and early adulthood, and probably help decrease intimate partner violence and self-directed violence in later life.[90][91]
+
+Evidence shows that the life skills acquired in social development programmes can reduce involvement in violence, improve social skills, boost educational achievement and improve job prospects. Life skills refer to social, emotional, and behavioural competencies which help children and adolescents effectively deal with the challenges of everyday life.
+
+Evaluation studies are beginning to support community interventions that aim to prevent violence against women by promoting gender equality. For instance, evidence suggests that programmes that combine microfinance with gender equity training can reduce intimate partner violence.[92][93] School-based programmes such as Safe Dates programme in the United States of America[94][95] and the Youth Relationship Project in Canada[96] have been found to be effective for reducing dating violence.
+
+Rules or expectations of behaviour – norms – within a cultural or social group can encourage violence. Interventions that challenge cultural and social norms supportive of violence can prevent acts of violence and have been widely used, but the evidence base for their effectiveness is currently weak. The effectiveness of interventions addressing dating violence and sexual abuse among teenagers and young adults by challenging social and cultural norms related to gender is supported by some evidence.[97][98]
+
+Interventions to identify victims of interpersonal violence and provide effective care and support are critical for protecting health and breaking cycles of violence from one generation to the next. Examples for which evidence of effectiveness is emerging includes: screening tools to identify victims of intimate partner violence and refer them to appropriate services;[99] psychosocial interventions – such as trauma-focused cognitive behavioural therapy – to reduce mental health problems associated with violence, including post-traumatic stress disorder;[100] and protection orders, which prohibit a perpetrator from contacting the victim,[101][102] to reduce repeat victimization among victims of intimate partner violence.
+
+Not surprisingly, scientific evidence about the effectiveness of interventions to prevent collective violence is lacking.[103] However, policies that facilitate reductions in poverty, that make decision-making more accountable, that reduce inequalities between groups, as well as policies that reduce access to biological, chemical, nuclear and other weapons have been recommended. When planning responses to violent conflicts, recommended approaches include assessing at an early stage who is most vulnerable and what their needs are, co-ordination of activities between various players and working towards global, national and local capabilities so as to deliver effective health services during the various stages of an emergency.[104]
+
+One of the main functions of law is to regulate violence.[105] Sociologist Max Weber stated that the state claims the monopoly of the legitimate use of force practised within the confines of a specific territory. Law enforcement is the main means of regulating nonmilitary violence in society. Governments regulate the use of violence through legal systems governing individuals and political authorities, including the police and military. Civil societies authorize some amount of violence, exercised through the police power, to maintain the status quo and enforce laws.
+
+However, German political theorist Hannah Arendt noted: "Violence can be justifiable, but it never will be legitimate ... Its justification loses in plausibility the farther its intended end recedes into the future. No one questions the use of violence in self-defence, because the danger is not only clear but also present, and the end justifying the means is immediate".[106] Arendt made a clear distinction between violence and power. Most political theorists regarded violence as an extreme manifestation of power whereas Arendt regarded the two concepts as opposites.[107]
+In the 20th century in acts of democide governments may have killed more than 260 million of their own people through police brutality, execution, massacre, slave labour camps, and sometimes through intentional famine.[108][109]
+
+Violent acts that are not carried out by the military or police and that are not in self-defense are usually classified as crimes, although not all crimes are violent crimes. Damage to property is classified as violent crime in some jurisdictions but not in all.[citation needed] The Federal Bureau of Investigation (FBI) classifies violence resulting in homicide into criminal homicide and justifiable homicide (e.g. self-defense).[110]
+
+The criminal justice approach sees its main task as enforcing laws that proscribe violence and ensuring that "justice is done". The notions of individual blame, responsibility, guilt, and culpability are central to criminal justice's approach to violence and one of the criminal justice system's main tasks is to "do justice", i.e. to ensure that offenders are properly identified, that the degree of their guilt is as accurately ascertained as possible, and that they are punished appropriately. To prevent and respond to violence, the criminal justice approach relies primarily on deterrence, incarceration and the punishment and rehabilitation of perpetrators.[111]
+
+The criminal justice approach, beyond justice and punishment, has traditionally emphasized indicated interventions, aimed at those who have already been involved in violence, either as victims or as perpetrators. One of the main reasons offenders are arrested, prosecuted, and convicted is to prevent further crimes – through deterrence (threatening potential offenders with criminal sanctions if they commit crimes), incapacitation (physically preventing offenders from committing further crimes by locking them up) and through rehabilitation (using time spent under state supervision to develop skills or change one's psychological make-up to reduce the likelihood of future offences).[112]
+
+In recent decades in many countries in the world, the criminal justice system has taken an increasing interest in preventing violence before it occurs. For instance, much of community and problem-oriented policing aims to reduce crime and violence by altering the conditions that foster it – and not to increase the number of arrests. Indeed, some police leaders have gone so far as to say the police should primarily be a crime prevention agency.[113] Juvenile justice systems – an important component of criminal justice systems – are largely based on the belief in rehabilitation and prevention. In the US, the criminal justice system has, for instance, funded school- and community-based initiatives to reduce children's access to guns and teach conflict resolution. In 1974, the US Department of Justice assumed primary responsibility for delinquency prevention programmes and created the Office of Juvenile Justice and Delinquency Prevention, which has supported the "Blueprints for violence prevention" programme at the University of Colorado Boulder.[114]
+
+The public health approach is a science-driven, population-based, interdisciplinary, intersectoral approach based on the ecological model which emphasizes primary prevention.[4] Rather than focusing on individuals, the public health approach aims to provide the maximum benefit for the largest number of people, and to extend better care and safety to entire populations. The public health approach is interdisciplinary, drawing upon knowledge from many disciplines including medicine, epidemiology, sociology, psychology, criminology, education and economics. Because all forms of violence are multi-faceted problems, the public health approach emphasizes a multi-sectoral response. It has been proved time and again that cooperative efforts from such diverse sectors as health, education, social welfare, and criminal justice are often necessary to solve what are usually assumed to be purely "criminal" or "medical" problems. The public health approach considers that violence, rather than being the result of any single factor, is the outcome of multiple risk factors and causes, interacting at four levels of a nested hierarchy (individual, close relationship/family, community and wider society) of the Social ecological model.
+
+From a public health perspective, prevention strategies can be classified into three types:
+
+A public health approach emphasizes the primary prevention of violence, i.e. stopping them from occurring in the first place. Until recently, this approach has been relatively neglected in the field, with the majority of resources directed towards secondary or tertiary prevention. Perhaps the most critical element of a public health approach to prevention is the ability to identify underlying causes rather than focusing upon more visible "symptoms". This allows for the development and testing of effective approaches to address the underlying causes and so improve health.
+
+The public health approach is an evidence-based and systematic process involving the following four steps:
+
+In many countries, violence prevention is still a new or emerging field in public health. The public health community has started only recently to realize the contributions it can make to reducing violence and mitigating its consequences. In 1949, Gordon called for injury prevention efforts to be based on the understanding of causes, in a similar way to prevention efforts for communicable and other diseases.[115] In 1962, Gomez, referring to the WHO definition of health, stated that it is obvious that violence does not contribute to "extending life" or to a "complete state of well-being". He defined violence as an issue that public health experts needed to address and stated that it should not be the primary domain of lawyers, military personnel, or politicians.[116]
+
+However, it is only in the last 30 years that public health has begun to address violence, and only in the last fifteen has it done so at the global level.[117] This is a much shorter period of time than public health has been tackling other health problems of comparable magnitude and with similarly severe lifelong consequences.
+
+The global public health response to interpersonal violence began in earnest in the mid-1990s. In 1996, the World Health Assembly adopted Resolution WHA49.25[118] which declared violence "a leading worldwide public health problem" and requested that the World Health Organization (WHO) initiate public health activities to (1) document and characterize the burden of violence, (2) assess the effectiveness of programmes, with particular attention to women and children and community-based initiatives, and (3) promote activities to tackle the problem at the international and national levels. The World Health Organization's initial response to this resolution was to create the Department of Violence and Injury Prevention and Disability and to publish the World report on violence and health (2002).[4]
+
+The case for the public health sector addressing interpersonal violence rests on four main arguments.[119] First, the significant amount of time health care professionals dedicate to caring for victims and perpetrators of violence has made them familiar with the problem and has led many, particularly in emergency departments, to mobilize to address it. The information, resources, and infrastructures the health care sector has at its disposal are an important asset for research and prevention work. Second, the magnitude of the problem and its potentially severe lifelong consequences and high costs to individuals and wider society call for population-level interventions typical of the public health approach. Third, the criminal justice approach, the other main approach to addressing violence (link to entry above), has traditionally been more geared towards violence that occurs between male youths and adults in the street and other public places – which makes up the bulk of homicides in most countries – than towards violence occurring in private settings such as child maltreatment, intimate partner violence and elder abuse – which makes up the largest share of non-fatal violence. Fourth, evidence is beginning to accumulate that a science-based public health approach is effective at preventing interpersonal violence.
+
+The human rights approach is based on the obligations of states to respect, protect and fulfill human rights and therefore to prevent, eradicate and punish violence. It recognizes violence as a violation of many human rights: the rights to life, liberty, autonomy and security of the person; the rights to equality and non-discrimination; the rights to be free from torture and cruel, inhuman and degrading treatment or punishment; the right to privacy; and the right to the highest attainable standard of health. These human rights are enshrined in international and regional treaties and national constitutions and laws, which stipulate the obligations of states, and include mechanisms to hold states accountable. The Convention on the Elimination of All Forms of Discrimination Against Women, for example, requires that countries party to the Convention take all appropriate steps to end violence against women. The Convention on the Rights of the Child in its Article 19 states that States Parties shall take all appropriate legislative, administrative, social and educational measures to protect the child from all forms of physical or mental violence, injury or abuse, neglect or negligent treatment, maltreatment or exploitation, including sexual abuse, while in the care of parent(s), legal guardian(s) or any other person who has the care of the child.
+
+Violence, as defined in the dictionary of human geography, "appears whenever power is in jeopardy" and "in and of itself stands emptied of strength and purpose: it is part of a larger matrix of socio-political power struggles".[120] Violence can be broadly divided into three broad categories – direct violence, structural violence and cultural violence.[120] Thus defined and delineated, it is of note, as Hyndman says, that "geography came late to theorizing violence"[120] in comparison to other social sciences. Social and human geography, rooted in the humanist, Marxist, and feminist subfields that emerged following the early positivist approaches and subsequent behavioral turn, have long been concerned with social and spatial justice.[121]
+Along with critical geographers and political geographers, it is these groupings of geographers that most often interact with violence. Keeping this idea of social/spatial justice via geography in mind, it is worthwhile to look at geographical approaches to violence in the context of politics.
+
+Derek Gregory and Alan Pred assembled the influential edited collection Violent Geographies: Fear, Terror, and Political Violence, which demonstrates how place, space, and landscape are foremost factors in the real and imagined practices of organized violence both historically and in the present.[122] Evidently, political violence often gives a part for the state to play. When "modern states not only claim a monopoly of the legitimate means of violence; they also routinely use the threat of violence to enforce the rule of law",[120] the law not only becomes a form of violence but is violence.[120] Philosopher Giorgio Agamben's concepts of state of exception and homo sacer are useful to consider within a geography of violence. The state, in the grip of a perceived, potential crisis (whether legitimate or not) takes preventative legal measures, such as a suspension of rights (it is in this climate, as Agamben demonstrates, that the formation of the Social Democratic and Nazi government's lager or concentration camp can occur). However, when this "in limbo" reality is designed to be in place "until further notice…the state of exception thus ceases to be referred to as an external and provisional state of factual danger and comes to be confused with juridical rule itself".[123] For Agamben, the physical space of the camp "is a piece of land placed outside the normal juridical order, but it is nevertheless not simply an external space".[123] At the scale of the body, in the state of exception, a person is so removed from their rights by "juridical procedures and deployments of power"[123] that "no act committed against them could appear any longer as a crime";[123] in other words, people become only homo sacer. Guantanamo Bay could also be said to represent the physicality of the state of exception in space, and can just as easily draw man as homo sacer.
+
+In the 1970s, genocides in Cambodia under the Khmer Rouge and Pol Pot resulted in the deaths of over two million Cambodians (which was 25% of the Cambodian population), forming one of the many contemporary examples of state-sponsored violence.[124] About fourteen thousand of these murders occurred at Choeung Ek, which is the best-known of the extermination camps referred to as the Killing Fields.[124] The killings were arbitrary; for example, a person could be killed for wearing glasses, since that was seen as associating them with intellectuals and therefore as making them part of the enemy. People were murdered with impunity because it was no crime; Cambodians were made homo sacer in a condition of bare life. The Killing Fields—manifestations of Agamben's concept of camps beyond the normal rule of law—featured the state of exception. As part of Pol Pot's "ideological intent…to create a purely agrarian society or cooperative",[124] he "dismantled the country's existing economic infrastructure and depopulated every urban area".[124] Forced movement, such as this forced movement applied by Pol Pot, is a clear display of structural violence. When "symbols of Cambodian society were equally disrupted, social institutions of every kind…were purged or torn down",[124] cultural violence (defined as when "any aspect of culture such as language, religion, ideology, art, or cosmology is used to legitimize direct or structural violence"[120]) is added to the structural violence of forced movement and to the direct violence, such as murder, at the Killing Fields. Vietnam eventually intervened and the genocide officially ended. However, ten million landmines left by opposing guerillas in the 1970s[124] continue to create a violent landscape in Cambodia.
+
+Human geography, though coming late to the theorizing table, has tackled violence through many lenses, including anarchist geography, feminist geography, Marxist geography, political geography, and critical geography. However, Adriana Cavarero notes that, "as violence spreads and assumes unheard-of forms, it becomes difficult to name in contemporary language".[125] Cavarero proposes that, in facing such a truth, it is prudent to reconsider violence as "horrorism"; that is, "as though ideally all the…victims, instead of their killers, ought to determine the name".[125] With geography often adding the forgotten spatial aspect to theories of social science, rather than creating them solely within the discipline, it seems that the self-reflexive contemporary geography of today may have an extremely important place in this current (re)imaging of violence, exemplified by Cavarero.[clarification needed]
+
+As of 2010, all forms of violence resulted in about 1.34 million deaths up from about 1 million in 1990.[126] Suicide accounts for about 883,000, interpersonal violence for 456,000 and collective violence for 18,000.[126] Deaths due to collective violence have decreased from 64,000 in 1990.[126]
+
+By way of comparison, the 1.5 millions deaths a year due to violence is greater than the number of deaths due to tuberculosis (1.34 million), road traffic injuries (1.21 million), and malaria (830'000), but slightly less than the number of people who die from HIV/AIDS (1.77 million).[127]
+
+For every death due to violence, there are numerous nonfatal injuries. In 2008, over 16 million cases of non-fatal violence-related injuries were severe enough to require medical attention. Beyond deaths and injuries, forms of violence such as child maltreatment, intimate partner violence, and elder maltreatment have been found to be highly prevalent.
+
+In the last 45 years, suicide rates have increased by 60% worldwide.[citation needed] Suicide is among the three leading causes of death among those aged 15–44 years in some countries, and the second leading cause of death in the 10–24 years age group.[128] These figures do not include suicide attempts which are up to 20 times more frequent than completed suicide.[citation needed] Suicide was the 16th leading cause of death worldwide in 2004 and is projected to increase to the 12th in 2030.[129] Although suicide rates have traditionally been highest among the male elderly, rates among young people have been increasing to such an extent that they are now the group at highest risk in a third of countries, in both developed and developing countries.[citation needed]
+
+Rates and patterns of violent death vary by country and region. In recent years, homicide rates have been highest in developing countries in Sub-Saharan Africa and Latin America and the Caribbean and lowest in East Asia, the western Pacific, and some countries in northern Africa.[130] Studies show a strong, inverse relationship between homicide rates and both economic development and economic equality. Poorer countries, especially those with large gaps between the rich and the poor, tend to have higher rates of homicide than wealthier countries. Homicide rates differ markedly by age and sex. Gender differences are least marked for children. For the 15 to 29 age group, male rates were nearly six times those for female rates; for the remaining age groups, male rates were from two to four times those for females.[131]
+
+Studies in a number of countries show that, for every homicide among young people age 10 to 24, 20 to 40 other young people receive hospital treatment for a violent injury.[4]
+
+Forms of violence such as child maltreatment and intimate partner violence are highly prevalent. Approximately 20% of women and 5–10% of men report being sexually abused as children, while 25–50% of all children report being physically abused.[132] A WHO multi-country study found that between 15–71% of women reported experiencing physical and/or sexual violence by an intimate partner at some point in their lives.[133]
+
+Wars grab headlines, but the individual risk of dying violently in an armed conflict is today relatively low—much lower than the risk of violent death in many countries that are not suffering from an armed conflict. For example, between 1976 and 2008, African Americans were victims of 329,825 homicides.[134][135] Although there is a widespread perception that war is the most dangerous form of armed violence in the world, the average person living in a conflict-affected country had a risk of dying violently in the conflict of about 2.0 per 100,000 population between 2004 and 2007. This can be compared to the average world homicide rate of 7.6 per 100,000 people. This illustration highlights the value of accounting for all forms of armed violence rather than an exclusive focus on conflict related violence. Certainly, there are huge variations in the risk of dying from armed conflict at the national and subnational level, and the risk of dying violently in a conflict in specific countries remains extremely high. In Iraq, for example, the direct conflict death rate for 2004–07 was 65 per 100,000 people per year and, in Somalia, 24 per 100,000 people. This rate even reached peaks of 91 per 100,000 in Iraq in 2006 and 74 per 100,000 in Somalia in 2007.[136]
+
+Scientific evidence for warfare has come from settled, sedentary communities.[137] Some scholars argue humans may have a predisposition for violence (chimpanzees, also great apes, have been known to kill members of competing groups for resources like food),[137] placing the origins of organized violence prior to modern settled societies.[138][137] However, actual evidence suggests that organized, large-scale, militaristic, or regular human-on-human violence was absent for the vast majority of the human timeline,[139][140][141] and is first documented to have started only relatively recently in the Holocene, an epoch that began about 11,700 years ago, probably with the advent of higher population densities due to sedentism.[140] Social anthropologist Douglas P. Fry writes that scholars are divided on the origins of this greater degree of violence—in other words, war-like behavior:
+
+There are basically two schools of thought on this issue. One holds that warfare... goes back at least to the time of the first thoroughly modern humans and even before then to the primate ancestors of the hominid lineage. The second positions on the origins of warfare sees war as much less common in the cultural and biological evolution of humans. Here, warfare is a latecomer on the cultural horizon, only arising in very specific material circumstances and being quite rare in human history until the development of agriculture in the past 10,000 years.[142]
+
+Jared Diamond in his books Guns, Germs and Steel and The Third Chimpanzee posits that the rise of large-scale warfare is the result of advances in technology and city-states. For instance, the rise of agriculture provided a significant increase in the number of individuals that a region could sustain over hunter-gatherer societies, allowing for development of specialized classes such as soldiers, or weapons manufacturers.
+
+In academia, the idea of the peaceful pre-history and non-violent tribal societies gained popularity with the post-colonial perspective. The trend, starting in archaeology and spreading to anthropology reached its height in the late half of the 20th century.[143] However, some newer research in archaeology and bioarchaeology may provide evidence that violence within and among groups is not a recent phenomenon.[144][unreliable source?] According to the book "The Bioarchaeology of Violence" violence is a behavior that is found throughout human history.[145]
+
+Lawrence H. Keeley at the University of Illinois writes in War Before Civilization that 87% of tribal societies were at war more than once per year, and that 65% of them were fighting continuously. He writes that the attrition rate of numerous close-quarter clashes, which characterize endemic warfare, produces casualty rates of up to 60%, compared to 1% of the combatants as is typical in modern warfare. "Primitive Warfare" of these small groups or tribes was driven by the basic need for sustenance and violent competition.[146]
+
+Fry explores Keeley's argument in depth and counters that such sources erroneously focus on the ethnography of hunters and gatherers in the present, whose culture and values have been infiltrated externally by modern civilization, rather than the actual archaeological record spanning some two million years of human existence. Fry determines that all present ethnographically studied tribal societies, "by the very fact of having been described and published by anthropologists, have been irrevocably impacted by history and modern colonial nation states" and that "many have been affected by state societies for at least 5000 years."[147]
+
+The relatively peaceful period since World War II is known as the Long Peace.
+
+Steven Pinker's 2011 book, The Better Angels of Our Nature, roused both acclaim and controversy by asserting that modern society is less violent than in periods of the past, whether on the short scale of decades or long scale of centuries or millennia.
+
+Steven Pinker argues that by every possible measure, every type of violence has drastically decreased since ancient and medieval times. A few centuries ago, for example, genocide was a standard practice in all kinds of warfare and was so common that historians did not even bother to mention it. Cannibalism and slavery have been greatly reduced in the last thousand years, and capital punishment is now banned in many countries. According to Pinker, rape, murder, warfare and animal cruelty have all seen drastic declines in the 20th century.[148] However, Pinker's analyses have met with much criticism, mainly concerning the statistical question of how to measure violence and whether it is in fact declining.[149][150][151]
+
+Beyond deaths and injuries, highly prevalent forms of violence (such as child maltreatment and intimate partner violence) have serious lifelong non-injury health consequences. Victims may engage in high-risk behaviours such as alcohol and substance misuse and smoking, which in turn can contribute to cardiovascular disorders, cancers, depression, diabetes and HIV/AIDS, resulting in premature death.[152] The balances of prevention, mitigation, mediation and exacerbation are complex, and vary with the underpinnings of violence.
+
+In countries with high levels of violence, economic growth can be slowed down, personal and collective security eroded, and social development impeded. Families edging out of poverty and investing in schooling their sons and daughters can be ruined through the violent death or severe disability of the main breadwinner. Communities can be caught in poverty traps where pervasive violence and deprivation form a vicious circle that stifles economic growth. For societies, meeting the direct costs of health, criminal justice, and social welfare responses to violence diverts many billions of dollars from more constructive societal spending. The much larger indirect costs of violence due to lost productivity and lost investment in education work together to slow economic development, increase socioeconomic inequality, and erode human and social capital.
+
+Additionally, communities with high level of violence do not provide the level of stability and predictability vital for a prospering business economy. Individuals will be less likely to invest money and effort towards growth in such unstable and violent conditions. One of the possible proves might be the study of Baten and Gust that used “regicide” as measurement unit to approximate the influence of interpersonal violence and depict the influence of high interpersonal violence on economic development and level of investments. The results of the research prove the correlation of the human capital and the interpersonal violence.[153]
+
+In 2016, the Institute for Economics and Peace, released the Economic Value of Peace report, which estimates the economic impact of violence and conflict on the global economy, the total economic impact of violence on the world economy in 2015 was estimated to be $13.6 trillion[154] in purchasing power parity terms.
+
+Religious and political ideologies have been the cause of interpersonal violence throughout history.[155] Ideologues often falsely accuse others of violence, such as the ancient blood libel against Jews, the medieval accusations of casting witchcraft spells against women, and modern accusations of satanic ritual abuse against day care center owners and others.[156]
+
+Both supporters and opponents of the 21st-century War on Terrorism regard it largely as an ideological and religious war.[157]
+
+Vittorio Bufacchi describes two different modern concepts of violence, one the "minimalist conception" of violence as an intentional act of excessive or destructive force, the other the "comprehensive conception" which includes violations of rights, including a long list of human needs.[158]
+
+Anti-capitalists assert that capitalism is violent. They believe private property and profit survive only because police violence defends them and that capitalist economies need war to expand.[159] They may use the term "structural violence" to describe the systematic ways in which a given social structure or institution kills people slowly by preventing them from meeting their basic needs, for example the deaths caused by diseases because of lack of medicine.[160]
+
+Frantz Fanon critiqued the violence of colonialism and wrote about the counter violence of the "colonized victims."[161][162][163]
+
+Throughout history, most religions and individuals like Mahatma Gandhi have preached that humans are capable of eliminating individual violence and organizing societies through purely nonviolent means. Gandhi himself once wrote: "A society organized and run on the basis of complete non-violence would be the purest anarchy."[164] Modern political ideologies which espouse similar views include pacifist varieties of voluntarism, mutualism, anarchism and libertarianism.
+
+Terence Fretheim writing about the Old Testament:
+
+For many people, ... only physical violence truly qualifies as violence. But, certainly, violence is more than killing people, unless one includes all those words and actions that kill people slowly. The effect of limitation to a “killing fields” perspective is the widespread neglect of many other forms of violence. We must insist that violence also refers to that which is psychologically destructive, that which demeans, damages, or depersonalizes others. In view of these considerations, violence may be defined as follows: any action, verbal or nonverbal, oral or written, physical or psychical, active or passive, public or private, individual or institutional/societal, human or divine, in whatever degree of intensity, that abuses, violates, injures, or kills. Some of the most pervasive and most dangerous forms of violence are those that are often hidden from view (against women and children, especially); just beneath the surface in many of our homes, churches, and communities is abuse enough to freeze the
+blood. Moreover, many forms of systemic violence often slip past our attention because they are so much a part of the infrastructure of life (e.g., racism, sexism, ageism).[165]

en/6.html.txt

@@ -0,0 +1,172 @@
+
+
+
+
+
+
+Apiformes (from Latin 'apis')
+
+Bees are flying insects closely related to wasps and ants, known for their role in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyletic lineage within the superfamily Apoidea. They are presently considered a clade, called Anthophila. There are over 16,000 known species of bees in seven recognized biological families.[1][2] Some species — including honey bees, bumblebees, and stingless bees — live socially in colonies while some species — including mason bees, carpenter bees, leafcutter bees, and sweat bees — are solitary.
+
+Bees are found on every continent except for Antarctica, in every habitat on the planet that contains insect-pollinated flowering plants. The most common bees in the Northern Hemisphere are the Halictidae, or sweat bees, but they are small and often mistaken for wasps or flies. Bees range in size from tiny stingless bee species, whose workers are less than 2 millimetres (0.08 in) long, to Megachile pluto, the largest species of leafcutter bee, whose females can attain a length of 39 millimetres (1.54 in).
+
+Bees feed on nectar and pollen, the former primarily as an energy source and the latter primarily for protein and other nutrients. Most pollen is used as food for their larvae. Vertebrate predators of bees include birds such as bee-eaters; insect predators include beewolves and dragonflies.
+
+Bee pollination is important both ecologically and commercially, and the decline in wild bees has increased the value of pollination by commercially managed hives of honey bees. The analysis of 353 wild bee and hoverfly species across Britain from 1980 to 2013 found the insects have been lost from a quarter of the places they inhabited in 1980.[3]
+
+Human beekeeping or apiculture has been practised for millennia, since at least the times of Ancient Egypt and Ancient Greece. Bees have appeared in mythology and folklore, through all phases of art and literature from ancient times to the present day, although primarily focused in the Northern Hemisphere where beekeeping is far more common.
+
+The ancestors of bees were wasps in the family Crabronidae, which were predators of other insects. The switch from insect prey to pollen may have resulted from the consumption of prey insects which were flower visitors and were partially covered with pollen when they were fed to the wasp larvae. This same evolutionary scenario may have occurred within the vespoid wasps, where the pollen wasps evolved from predatory ancestors. Until recently, the oldest non-compression bee fossil had been found in New Jersey amber, Cretotrigona prisca of Cretaceous age, a corbiculate bee.[4] A bee fossil from the early Cretaceous (~100 mya), Melittosphex burmensis, is considered "an extinct lineage of pollen-collecting Apoidea sister to the modern bees".[5] Derived features of its morphology (apomorphies) place it clearly within the bees, but it retains two unmodified ancestral traits (plesiomorphies) of the legs (two mid-tibial spurs, and a slender hind basitarsus), showing its transitional status.[5] By the Eocene (~45 mya) there was already considerable diversity among eusocial bee lineages.[6][a]
+
+The highly eusocial corbiculate Apidae appeared roughly 87 Mya, and the Allodapini (within the Apidae) around 53 Mya.[9]
+The Colletidae appear as fossils only from the late Oligocene (~25 Mya) to early Miocene.[10]
+The Melittidae are known from Palaeomacropis eocenicus in the Early Eocene.[11]
+The Megachilidae are known from trace fossils (characteristic leaf cuttings) from the Middle Eocene.[12]
+The Andrenidae are known from the Eocene-Oligocene boundary, around 34 Mya, of the Florissant shale.[13]
+The Halictidae first appear in the Early Eocene[14] with species[15][16] found in amber. The Stenotritidae are known from fossil brood cells of Pleistocene age.[17]
+
+The earliest animal-pollinated flowers were shallow, cup-shaped blooms pollinated by insects such as beetles, so the syndrome of insect pollination was well established before the first appearance of bees. The novelty is that bees are specialized as pollination agents, with behavioral and physical modifications that specifically enhance pollination, and are the most efficient pollinating insects. In a process of coevolution, flowers developed floral rewards[18] such as nectar and longer tubes, and bees developed longer tongues to extract the nectar.[19] Bees also developed structures known as scopal hairs and pollen baskets to collect and carry pollen. The location and type differ among and between groups of bees. Most species have scopal hairs on their hind legs or on the underside of their abdomens. Some species in the family Apidae have pollen baskets on their hind legs, while very few lack these and instead collect pollen in their crops.[2] The appearance of these structures drove the adaptive radiation of the angiosperms, and, in turn, bees themselves.[7] Bees coevolved not only with flowers but it is believed that some species coevolved with mites. Some provide tufts of hairs called acarinaria that appear to provide lodgings for mites; in return, it is believed that mites eat fungi that attack pollen, so the relationship in this case may be mutualistc.[20][21]
+
+This phylogenetic tree is based on Debevic et al, 2012, which used molecular phylogeny to demonstrate that the bees (Anthophila) arose from deep within the Crabronidae, which is therefore paraphyletic. The placement of the Heterogynaidae is uncertain.[22] The small subfamily Mellininae was not included in this analysis.
+
+Ampulicidae (Cockroach wasps)
+
+Heterogynaidae (possible placement #1)
+
+Sphecidae (sensu stricto)
+
+Crabroninae (part of "Crabronidae")
+
+Bembicini
+
+Nyssonini, Astatinae
+
+Heterogynaidae (possible placement #2)
+
+Pemphredoninae, Philanthinae
+
+Anthophila (bees)
+
+This cladogram of the bee families is based on Hedtke et al., 2013, which places the former families Dasypodaidae and Meganomiidae as subfamilies inside the Melittidae.[23] English names, where available, are given in parentheses.
+
+Melittidae (inc. Dasypodainae, Meganomiinae) at least 50 Mya
+
+Apidae (inc. honeybees, cuckoo bees, carpenter bees) ≈87 Mya
+
+Megachilidae (mason, leafcutter bees) ≈50 Mya
+
+Andrenidae (mining bees) ≈34 Mya
+
+Halictidae (sweat bees) ≈50 Mya
+
+Colletidae (plasterer bees) ≈25 Mya
+
+Stenotritidae (large Australian bees) ≈2 Mya
+
+Bees differ from closely related groups such as wasps by having branched or plume-like setae (hairs), combs on the forelimbs for cleaning their antennae, small anatomical differences in limb structure, and the venation of the hind wings; and in females, by having the seventh dorsal abdominal plate divided into two half-plates.[24]
+
+Bees have the following characteristics:
+
+The largest species of bee is thought to be Wallace's giant bee Megachile pluto, whose females can attain a length of 39 millimetres (1.54 in).[26] The smallest species may be dwarf stingless bees in the tribe Meliponini whose workers are less than 2 millimetres (0.08 in) in length.[27]
+
+According to inclusive fitness theory, organisms can gain fitness not just through increasing their own reproductive output, but also that of close relatives. In evolutionary terms, individuals should help relatives when Cost < Relatedness * Benefit. The requirements for eusociality are more easily fulfilled by haplodiploid species such as bees because of their unusual relatedness structure.[28]
+
+In haplodiploid species, females develop from fertilized eggs and males from unfertilized eggs. Because a male is haploid (has only one copy of each gene), his daughters (which are diploid, with two copies of each gene) share 100% of his genes and 50% of their mother's. Therefore, they share 75% of their genes with each other. This mechanism of sex determination gives rise to what W. D. Hamilton termed "supersisters", more closely related to their sisters than they would be to their own offspring.[29] Workers often do not reproduce, but they can pass on more of their genes by helping to raise their sisters (as queens) than they would by having their own offspring (each of which would only have 50% of their genes), assuming they would produce similar numbers. This unusual situation has been proposed as an explanation of the multiple (at least 9) evolutions of eusociality within Hymenoptera.[30][31]
+
+Haplodiploidy is neither necessary nor sufficient for eusociality. Some eusocial species such as termites are not haplodiploid. Conversely, all bees are haplodiploid but not all are eusocial, and among eusocial species many queens mate with multiple males, creating half-sisters that share only 25% of each-other's genes.[32] But, monogamy (queens mating singly) is the ancestral state for all eusocial species so far investigated, so it is likely that haplodiploidy contributed to the evolution of eusociality in bees.[30]
+
+Bees may be solitary or may live in various types of communities. Eusociality appears to have originated from at least three independent origins in halictid bees.[33] The most advanced of these are species with eusocial colonies; these are characterised by cooperative brood care and a division of labour into reproductive and non-reproductive adults, plus overlapping generations.[34] This division of labour creates specialized groups within eusocial societies which are called castes. In some species, groups of cohabiting females may be sisters, and if there is a division of labour within the group, they are considered semisocial. The group is called eusocial if, in addition, the group consists of a mother (the queen) and her daughters (workers). When the castes are purely behavioural alternatives, with no morphological differentiation other than size, the system is considered primitively eusocial, as in many paper wasps; when the castes are morphologically discrete, the system is considered highly eusocial.[19]
+
+True honey bees (genus Apis, of which seven species are currently recognized) are highly eusocial, and are among the best known insects. Their colonies are established by swarms, consisting of a queen and several hundred workers. There are 29 subspecies of one of these species, Apis mellifera, native to Europe, the Middle East, and Africa. Africanized bees are a hybrid strain of A. mellifera that escaped from experiments involving crossing European and African subspecies; they are extremely defensive.[35]
+
+Stingless bees are also highly eusocial. They practise mass provisioning, with complex nest architecture and perennial colonies also established via swarming.[36]
+
+Many bumblebees are eusocial, similar to the eusocial Vespidae such as hornets in that the queen initiates a nest on her own rather than by swarming. Bumblebee colonies typically have from 50 to 200 bees at peak population, which occurs in mid to late summer. Nest architecture is simple, limited by the size of the pre-existing nest cavity, and colonies rarely last more than a year.[37]  In 2011, the International Union for Conservation of Nature set up the Bumblebee Specialist Group to review the threat status of all bumblebee species worldwide using the IUCN Red List criteria.[38]
+
+There are many more species of primitively eusocial than highly eusocial bees, but they have been studied less often. Most are in the family Halictidae, or "sweat bees". Colonies are typically small, with a dozen or fewer workers, on average. Queens and workers differ only in size, if at all. Most species have a single season colony cycle, even in the tropics, and only mated females hibernate. A few species have long active seasons and attain colony sizes in the hundreds, such as Halictus hesperus.[39] Some species are eusocial in parts of their range and solitary in others,[40] or have a mix of eusocial and solitary nests in the same population.[41] The orchid bees (Apidae) include some primitively eusocial species with similar biology. Some allodapine bees (Apidae) form primitively eusocial colonies, with progressive provisioning: a larva's food is supplied gradually as it develops, as is the case in honey bees and some bumblebees.[42]
+
+Most other bees, including familiar insects such as carpenter bees, leafcutter bees and mason bees are solitary in the sense that every female is fertile, and typically inhabits a nest she constructs herself. There is no division of labor so these nests lack queens and worker bees for these species. Solitary bees typically produce neither honey nor beeswax. 
+Bees collect pollen to feed their young, and have the necessary adaptations to do this. However, certain wasp species such as pollen wasps have similar behaviours, and a few species of bee scavenge from carcases to feed their offspring.[24] Solitary bees are important pollinators; they gather pollen to provision their nests with food for their brood. Often it is mixed with nectar to form a paste-like consistency. Some solitary bees have advanced types of pollen-carrying structures on their bodies. Very few species of solitary bee are being cultured for commercial pollination. Most of these species belong to a distinct set of genera which are commonly known by their nesting behavior or preferences, namely: carpenter bees, sweat bees, mason bees, plasterer bees, squash bees, dwarf carpenter bees, leafcutter bees, alkali bees and digger bees.[43]
+
+Most solitary bees nest in the ground in a variety of soil textures and conditions while others create nests in hollow reeds or twigs, holes in wood. The female typically creates a compartment (a "cell") with an egg and some provisions for the resulting larva, then seals it off. A nest may consist of numerous cells. When the nest is in wood, usually the last (those closer to the entrance) contain eggs that will become males. The adult does not provide care for the brood once the egg is laid, and usually dies after making one or more nests. The males typically emerge first and are ready for mating when the females emerge. Solitary bees are either stingless or very unlikely to sting (only in self-defense, if ever).[44][45]
+
+While solitary, females each make individual nests. Some species, such as the European mason bee Hoplitis anthocopoides,[46] and the Dawson's Burrowing bee, Amegilla dawsoni,[47] are gregarious, preferring to make nests near others of the same species, and giving the appearance of being social. Large groups of solitary bee nests are called aggregations, to distinguish them from colonies. In some species, multiple females share a common nest, but each makes and provisions her own cells independently. This type of group is called "communal" and is not uncommon. The primary advantage appears to be that a nest entrance is easier to defend from predators and parasites when there are multiple females using that same entrance on a regular basis.[46]
+
+The life cycle of a bee, be it a solitary or social species, involves the laying of an egg, the development through several moults of a legless larva, a pupation stage during which the insect undergoes complete metamorphosis, followed by the emergence of a winged adult. Most solitary bees and bumble bees in temperate climates overwinter as adults or pupae and emerge in spring when increasing numbers of flowering plants come into bloom. The males usually emerge first and search for females with which to mate. The sex of a bee is determined by whether or not the egg is fertilised; after mating, a female stores the sperm, and determines which sex is required at the time each individual egg is laid, fertilised eggs producing female offspring and unfertilised eggs, males. Tropical bees may have several generations in a year and no diapause stage.[48][49][50][51]
+
+The egg is generally oblong, slightly curved and tapering at one end. Solitary bees, lay each egg in a separate cell with a supply of mixed pollen and nectar next to it. This may be rolled into a pellet or placed in a pile and is known as mass provisioning. Social bee species provision progressively, that is, they feed the larva regularly while it grows. The nest varies from a hole in the ground or in wood, in solitary bees, to a substantial structure with wax combs in bumblebees and honey bees.[52]
+
+In most species, larvae are whitish grubs, roughly oval and bluntly-pointed at both ends. They have 15 segments and spiracles in each segment for breathing. They have no legs but move within the cell, helped by tubercles on their sides. They have short horns on the head, jaws for chewing food and an appendage on either side of the mouth tipped with a bristle. There is a gland under the mouth that secretes a viscous liquid which solidifies into the silk they use to produce a cocoon. The cocoon is semi-transparent and the pupa can be seen through it. Over the course of a few days, the larva undergoes metamorphosis into a winged adult. When ready to emerge, the adult splits its skin dorsally and climbs out of the exuviae and breaks out of the cell.[52]
+
+Nest of common carder bumblebee, wax canopy removed to show winged workers and pupae in irregularly placed wax cells
+
+Carpenter bee nests in a cedar wood beam (sawn open)
+
+Honeybees on brood comb with eggs and larvae in cells
+
+Antoine Magnan's 1934 book Le vol des insectes, says that he and André Sainte-Laguë had applied the equations of air resistance to insects and found that their flight could not be explained by fixed-wing calculations, but that "One shouldn't be surprised that the results of the calculations don't square with reality".[53] This has led to a common misconception that bees "violate aerodynamic theory". In fact it merely confirms that bees do not engage in fixed-wing flight, and that their flight is explained by other mechanics, such as those used by helicopters.[54] In 1996 it was shown that vortices created by many insects' wings helped to provide lift.[55] High-speed cinematography[56] and robotic mock-up of a bee wing[57] showed that lift was generated by "the unconventional combination of short, choppy wing strokes, a rapid rotation of the wing as it flops over and reverses direction, and a very fast wing-beat frequency". Wing-beat frequency normally increases as size decreases, but as the bee's wing beat covers such a small arc, it flaps approximately 230 times per second, faster than a fruitfly (200 times per second) which is 80 times smaller.[58]
+
+The ethologist Karl von Frisch studied navigation in the honey bee. He showed that honey bees communicate by the waggle dance, in which a worker indicates the location of a food source to other workers in the hive. He demonstrated that bees can recognize a desired compass direction in three different ways: by the sun, by the polarization pattern of the blue sky, and by the earth's magnetic field. He showed that the sun is the preferred or main compass; the other mechanisms are used under cloudy skies or inside a dark beehive.[59] Bees navigate using spatial memory with a "rich, map-like organization".[60]
+
+The gut of bees is relatively simple, but multiple metabolic strategies exist in the gut microbiota.[61] Pollinating bees consume nectar and pollen, which require different digestion strategies by somewhat specialized bacteria. While nectar is a liquid of mostly monosaccharide sugars and so easily absorbed, pollen contains complex polysaccharides: branching pectin and hemicellulose.[62] Approximately five groups of bacteria are involved in digestion. Three groups specialize in simple sugars (Snodgrassella and two groups of Lactobacillus), and two other groups in complex sugars (Gilliamella and Bifidobacterium). Digestion of pectin and hemicellulose is dominated by bacterial clades Gilliamella and Bifidobacterium respectively. Bacteria that cannot digest polysaccharides obtain enzymes from their neighbors, and bacteria that lack certain amino acids do the same, creating multiple ecological niches.[63]
+
+Although most bee species are nectarivorous and palynivorous, some are not. Particularly unusual are vulture bees in the genus Trigona, which consume carrion and wasp brood, turning meat into a honey-like substance.[64]
+
+Most bees are polylectic (generalist) meaning they collect pollen from a range of flowering plants, but some are oligoleges (specialists), in that they only gather pollen from one or a few species or genera of closely related plants.[65] Specialist pollinators also include bee species which gather floral oils instead of pollen, and male orchid bees, which gather aromatic compounds from orchids (one of the few cases where male bees are effective pollinators). Bees are able to sense the presence of desirable flowers through ultraviolet patterning on flowers, floral odors,[66] and even electromagnetic fields.[67] Once landed, a bee then uses nectar quality[66] and pollen taste[68] to determine whether to continue visiting similar flowers.
+
+In rare cases, a plant species may only be effectively pollinated by a single bee species, and some plants are endangered at least in part because their pollinator is also threatened. But, there is a pronounced tendency for oligolectic bees to be associated with common, widespread plants visited by multiple pollinator species. For example, the creosote bush in the arid parts of the United States southwest is associated with some 40 oligoleges.[69]
+
+Many bees are aposematically coloured, typically orange and black, warning of their ability to defend themselves with a powerful sting. As such they are models for Batesian mimicry by non-stinging insects such as bee-flies, robber flies and hoverflies,[70] all of which gain a measure of protection by superficially looking and behaving like bees.[70]
+
+Bees are themselves Müllerian mimics of other aposematic insects with the same colour scheme, including wasps, lycid and other beetles, and many butterflies and moths (Lepidoptera) which are themselves distasteful, often through acquiring bitter and poisonous chemicals from their plant food. All the Müllerian mimics, including bees, benefit from the reduced risk of predation that results from their easily recognised warning coloration.[71]
+
+Bees are also mimicked by plants such as the bee orchid which imitates both the appearance and the scent of a female bee; male bees attempt to mate (pseudocopulation) with the furry lip of the flower, thus pollinating it.[72]
+
+Brood parasites occur in several bee families including the apid subfamily Nomadinae.[73] Females of these species lack pollen collecting structures (the scopa) and do not construct their own nests. They typically enter the nests of pollen collecting species, and lay their eggs in cells provisioned by the host bee. When the "cuckoo" bee larva hatches, it consumes the host larva's pollen ball, and often the host egg also.[74] In particular, the Arctic bee species, Bombus hyperboreus is an aggressive species that attacks and enslaves other bees of the same subgenus. However, unlike many other bee brood parasites, they have pollen baskets and often collect pollen.[75]
+
+In Southern Africa, hives of African honeybees (A. mellifera scutellata) are being destroyed by parasitic workers of the Cape honeybee, A. m. capensis. These lay diploid eggs ("thelytoky"), escaping normal worker policing, leading to the colony's destruction; the parasites can then move to other hives.[76]
+
+The cuckoo bees in the Bombus subgenus Psithyrus are closely related to, and resemble, their hosts in looks and size. This common pattern gave rise to the ecological principle "Emery's rule". Others parasitize bees in different families, like Townsendiella, a nomadine apid, two species of which are cleptoparasites of the dasypodaid genus Hesperapis,[77] while the other species in the same genus attacks halictid bees.[78]
+
+Four bee families (Andrenidae, Colletidae, Halictidae, and Apidae) contain some species that are crepuscular. Most are tropical or subtropical, but some live in arid regions at higher latitudes. These bees have greatly enlarged ocelli, which are extremely sensitive to light and dark, though incapable of forming images. Some have refracting superposition compound eyes: these combine the output of many elements of their compound eyes to provide enough light for each retinal photoreceptor. Their ability to fly by night enables them to avoid many predators, and to exploit flowers that produce nectar only or also at night.[79]
+
+Vertebrate predators of bees include bee-eaters, shrikes and flycatchers, which make short sallies to catch insects in flight.[80] Swifts and swallows[80] fly almost continually, catching insects as they go. The honey buzzard attacks bees' nests and eats the larvae.[81] The greater honeyguide interacts with humans by guiding them to the nests of wild bees. The humans break open the nests and take the honey and the bird feeds on the larvae and the wax.[82] Among mammals, predators such as the badger dig up bumblebee nests and eat both the larvae and any stored food.[83]
+
+Specialist ambush predators of visitors to flowers include crab spiders, which wait on flowering plants for pollinating insects; predatory bugs, and praying mantises,[80] some of which (the flower mantises of the tropics) wait motionless, aggressive mimics camouflaged as flowers.[84] Beewolves are large wasps that habitually attack bees;[80] the ethologist Niko Tinbergen estimated that a single colony of the beewolf Philanthus triangulum might kill several thousand honeybees in a day: all the prey he observed were honeybees.[85] Other predatory insects that sometimes catch bees include robber flies and dragonflies.[80] Honey bees are affected by parasites including acarine and Varroa mites.[86] However, some bees are believed to have a mutualistic relationship with mites.[21]
+
+Homer's Hymn to Hermes describes three bee-maidens with the power of divination and thus speaking truth, and identifies the food of the gods as honey. Sources associated the bee maidens with Apollo and, until the 1980s, scholars followed Gottfried Hermann (1806) in incorrectly identifying the bee-maidens with the Thriae.[87] Honey, according to a Greek myth, was discovered by a nymph called Melissa ("Bee"); and honey was offered to the Greek gods from Mycenean times. Bees were also associated with the Delphic oracle and the prophetess was sometimes called a bee.[88]
+
+The image of a community of honey bees has been used from ancient to modern times, in Aristotle and Plato; in Virgil and Seneca; in Erasmus and Shakespeare; Tolstoy, and by political and social theorists such as Bernard Mandeville and Karl Marx as a model for human society.[89] In English folklore, bees would be told of important events in the household, in a custom known as "Telling the bees".[90]
+
+Some of the oldest examples of bees in art are rock paintings in Spain which have been dated to 15,000 BC.[91]
+
+W. B. Yeats's poem The Lake Isle of Innisfree (1888) contains the couplet "Nine bean rows will I have there, a hive for the honey bee, / And live alone in the bee loud glade." At the time he was living in Bedford Park in the West of London.[92] Beatrix Potter's illustrated book The Tale of Mrs Tittlemouse (1910) features Babbity Bumble and her brood (pictured). Kit Williams' treasure hunt book The Bee on the Comb (1984) uses bees and beekeeping as part of its story and puzzle. Sue Monk Kidd's The Secret Life of Bees (2004), and the 2009 film starring Dakota Fanning, tells the story of a girl who escapes her abusive home and finds her way to live with a family of beekeepers, the Boatwrights.
+
+The humorous 2007 animated film Bee Movie used Jerry Seinfeld's first script and was his first work for children; he starred as a bee named Barry B. Benson, alongside Renée Zellweger. Critics found its premise awkward and its delivery tame.[93] Dave Goulson's A Sting in the Tale (2014) describes his efforts to save bumblebees in Britain, as well as much about their biology. The playwright Laline Paull's fantasy The Bees (2015) tells the tale of a hive bee named Flora 717 from hatching onwards.[94]
+
+Humans have kept honey bee colonies, commonly in hives, for millennia. Beekeepers collect honey, beeswax, propolis, pollen, and royal jelly from hives; bees are also kept to pollinate crops and to produce bees for sale to other beekeepers.
+
+Depictions of humans collecting honey from wild bees date to 15,000 years ago; efforts to domesticate them are shown in Egyptian art around 4,500 years ago.[95] Simple hives and smoke were used;[96][97] jars of honey were found in the tombs of pharaohs such as Tutankhamun. From the 18th century, European understanding of the colonies and biology of bees allowed the construction of the moveable comb hive so that honey could be harvested without destroying the colony.[98][99] Among Classical Era authors, beekeeping with the use of smoke is described in Aristotle's History of Animals Book 9.[100] The account mentions that bees die after stinging; that workers remove corpses from the hive, and guard it; castes including workers and non-working drones, but "kings" rather than queens; predators including toads and bee-eaters; and the waggle dance, with the "irresistible suggestion" of άpοσειονται ("aroseiontai", it waggles) and παρακολουθούσιν ("parakolouthousin", they watch).[101][b]
+
+Beekeeping is described in detail by Virgil in his Eclogues; it is also mentioned in his Aeneid, and in Pliny's Natural History.[101]
+
+Bees play an important role in pollinating flowering plants, and are the major type of pollinator in many ecosystems that contain flowering plants. It is estimated that one third of the human food supply depends on pollination by insects, birds and bats, most of which is accomplished by bees, whether wild or domesticated.[102][103] Over the last half century, there has been a general decline in the species richness of wild bees and other pollinators, probably attributable to stress from increased parasites and disease, the use of pesticides, and a general decrease in the number of wild flowers. Climate change probably exacerbates the problem.[104]
+
+Contract pollination has overtaken the role of honey production for beekeepers in many countries. After the introduction of Varroa mites, feral honey bees declined dramatically in the US, though their numbers have since recovered.[105][106] The number of colonies kept by beekeepers declined slightly, through urbanization, systematic pesticide use, tracheal and Varroa mites, and the closure of beekeeping businesses. In 2006 and 2007 the rate of attrition increased, and was described as colony collapse disorder.[107] In 2010 invertebrate iridescent virus and the fungus Nosema ceranae were shown to be in every killed colony, and deadly in combination.[108][109][110][111] Winter losses increased to about 1/3.[112][113] Varroa mites were thought to be responsible for about half the losses.[114]
+
+Apart from colony collapse disorder, losses outside the US have been attributed to causes including pesticide seed dressings, using neonicotinoids such as Clothianidin, Imidacloprid and Thiamethoxam.[115][116] From 2013 the European Union restricted some pesticides to stop bee populations from declining further.[117] In 2014 the Intergovernmental Panel on Climate Change report warned that bees faced increased risk of extinction because of global warming.[118] In 2018 the European Union decided to ban field use of all three major neonicotinoids; they remain permitted in veterinary, greenhouse, and vehicle transport usage.[119]
+
+Farmers have focused on alternative solutions to mitigate these problems. By raising native plants, they provide food for native bee pollinators like Lasioglossum vierecki[120] and L. leucozonium,[121] leading to less reliance on honey bee populations.
+
+Honey is a natural product produced by bees and stored for their own use, but its sweetness has always appealed to humans. Before domestication of bees was even attempted, humans were raiding their nests for their honey. Smoke was often used to subdue the bees and such activities are depicted in rock paintings in Spain dated to 15,000 BC.[91]
+
+Honey bees are used commercially to produce honey.[122] They also produce some substances used as dietary supplements with possible health benefits, pollen,[123] propolis,[124] and royal jelly,[125] though all of these can also cause allergic reactions.
+
+Bees are partly considered edible insects. Indigenous people in many countries eat insects, including the larvae and pupae of bees, mostly stingless species. They also gather larvae, pupae and surrounding cells, known as bee brood, for consumption.[126] In the Indonesian dish botok tawon from Central and East Java, bee larvae are eaten as a companion to rice, after being mixed with shredded coconut,  wrapped in banana leaves, and steamed.[127][128]
+
+Bee brood (pupae and larvae) although low in calcium, has been found to be high in protein  and carbohydrate, and a useful source of phosphorus, magnesium, potassium, and trace minerals iron, zinc, copper, and selenium. In addition, while bee brood was high in fat, it contained no fat soluble vitamins (such as A, D, and E) but it was a good source of most of the water-soluble B-vitamins including choline as well as vitamin C. The fat was composed mostly of saturated and monounsaturated fatty acids with 2.0% being polyunsaturated fatty acids.[129][130]
+
+Apitherapy is a branch of alternative medicine that uses honey bee products, including raw honey, royal jelly, pollen, propolis, beeswax and apitoxin (Bee venom).[131] The claim that apitherapy treats cancer, which some proponents of apitherapy make, remains unsupported by evidence-based medicine.[132][133]
+
+The painful stings of bees are mostly associated with the poison gland and the Dufour's gland which are abdominal exocrine glands containing various chemicals. In Lasioglossum leucozonium, the Dufour's Gland mostly contains octadecanolide as well as some eicosanolide. There is also evidence of n-triscosane, n-heptacosane,[134] and 22-docosanolide.[135] However, the secretions of these glands could also be used for nest construction.[134]
+

en/60.html.txt

@@ -0,0 +1,207 @@
+
+
+An airport is an aerodrome with extended facilities, mostly for commercial air transport.[1][2] Airports often have facilities to store and maintain aircraft, and a control tower. An airport consists of a landing area, which comprises an aerially accessible open space including at least one operationally active surface such as a runway for a plane to take off[3] or a helipad,[4] and often includes adjacent utility buildings such as control towers, hangars[5] and terminals. Larger airports may have airport aprons, taxiway bridges, air traffic control centres, passenger facilities such as restaurants and lounges, and emergency services. In some countries, the US in particular, airports also typically have one or more fixed-base operators, serving general aviation.
+
+An airport solely serving helicopters is called a heliport. An airport for use by seaplanes and amphibious aircraft is called a seaplane base. Such a base typically includes a stretch of open water for takeoffs and landings, and seaplane docks for tying-up.
+
+An international airport has additional facilities for customs and passport control as well as incorporating all the aforementioned elements. Such airports rank among the most complex and largest of all built typologies, with 15 of the top 50 buildings by floor area being airport terminals.[citation needed][6]
+
+The terms aerodrome, airfield, and airstrip also refer to airports, and the terms heliport, seaplane base, and STOLport refer to airports dedicated exclusively to helicopters, seaplanes, and short take-off and landing aircraft.
+
+In colloquial use in certain environments, the terms airport and aerodrome are often interchanged. However, in general, the term airport may imply or confer a certain stature upon the aviation facility that other aerodromes may not have achieved. In some jurisdictions, airport is a legal term of art reserved exclusively for those aerodromes certified or licensed as airports by the relevant national aviation authority after meeting specified certification criteria or regulatory requirements.[7]
+
+That is to say, all airports are aerodromes, but not all aerodromes are airports. In jurisdictions where there is no legal distinction between aerodrome and airport, which term to use in the name of an aerodrome may be a commercial decision. In US technical/legal usage, landing area is used instead of aerodrome, and airport means "a landing area used regularly by aircraft for receiving or discharging passengers or cargo".[8]
+
+Smaller or less-developed airfields, which represent the vast majority, often have a single runway shorter than 1,000 m (3,300 ft). Larger airports for airline flights generally have paved runways of 2,000 m (6,600 ft) or longer. Skyline Airport in Inkom, Idaho has a runway that is only 122 m (400 ft) long.[9]
+
+In the United States, the minimum dimensions for dry, hard landing fields are defined by the FAR Landing And Takeoff Field Lengths. These include considerations for safety margins during landing and takeoff.
+
+The longest public-use runway in the world is at Qamdo Bamda Airport in China. It has a length of 5,500 m (18,045 ft). The world's widest paved runway is at Ulyanovsk Vostochny Airport in Russia and is 105 m (344 ft) wide.
+
+As of 2009[update], the CIA stated that there were approximately 44,000 "airports or airfields recognizable from the air" around the world, including 15,095 in the US, the US having the most in the world.[10][11]
+
+Most of the world's large airports are owned by local, regional, or national government bodies who then lease the airport to private corporations who oversee the airport's operation. For example, in the UK the state-owned British Airports Authority originally operated eight of the nation's major commercial airports – it was subsequently privatized in the late 1980s, and following its takeover by the Spanish Ferrovial consortium in 2006, has been further divested and downsized to operating just Heathrow. Germany's Frankfurt Airport is managed by the quasi-private firm Fraport. While in India GMR Group operates, through joint ventures, Indira Gandhi International Airport and Rajiv Gandhi International Airport. Bengaluru International Airport and Chhatrapati Shivaji International Airport are controlled by GVK Group. The rest of India's airports are managed by the Airports Authority of India. In Pakistan nearly all civilian airports are owned and operated by the Pakistan Civil Aviation Authority except for Sialkot International Airport which has the distinction of being the first privately owned public airport in Pakistan and South Asia[citation needed].
+
+In the US, commercial airports are generally operated directly by government entities or government-created airport authorities (also known as port authorities), such as the Los Angeles World Airports authority that oversees several airports in the Greater Los Angeles area, including Los Angeles International Airport[citation needed].
+
+In Canada, the federal authority, Transport Canada, divested itself of all but the remotest airports in 1999/2000. Now most airports in Canada are owned and operated by individual legal authorities or are municipally owned.
+
+Many US airports still lease part or all of their facilities to outside firms, who operate functions such as retail management and parking. All US commercial airport runways are certified by the FAA[12] under the Code of Federal Regulations Title 14 Part 139, "Certification of Commercial Service Airports"[13] but maintained by the local airport under the regulatory authority of the FAA.
+
+Despite the reluctance to privatize airports in the US (contrary to the FAA sponsoring a privatization program since 1996), the government-owned, contractor-operated (GOCO) arrangement is the standard for the operation of commercial airports in the rest of the world.
+
+The Airport & Airway Trust Fund (AATF) was created by the Airport and Airway Development in 1970 which finances aviation programs in the United States.[14] Airport Improvement Program (AIP), Facilities and Equipment (F&E), and Research, Engineering, and Development (RE&D) are the three major accounts of Federal Aviation Administration which are financed by the AATF, as well as pays for the FAA's Operation and Maintenance (O&M) account.[15] The funding of these accounts are dependent on the taxes the airports generate of revenues. Passenger tickets, fuel, and cargo tax are the taxes that are paid by the passengers and airlines help fund these accounts.[16]
+
+Airports revenues are divided into three major parts: aeronautical revenue, non-aeronautical revenue, and non-operating revenue. Aeronautical revenue makes up 56%, non-aeronautical revenue makes up 40%, and non-operating revenue makes up 4% of the total revenue of airports.[17]
+
+Aeronautical revenue are generated through airline rents and landing, passenger service, parking, and hangar fees. Landing fees are charged per aircraft for landing an airplane in the airport property.[18] Landing fees are calculated through the landing weight and the size of the aircraft which varies but most of the airports have a fixed rate and a charge extra for extra weight.[19] Passenger service fees are charges per passengers for the facilities used on a flight like water, food, wifi and shows which is paid while paying for an airline ticket.[citation needed] Aircraft parking is also a major revenue source for airports. Aircraft are parked for a certain amount of time before or after takeoff and have to pay to park there.[20] Every airport has his own rates of parking but at John F Kennedy airport in New York City charges $45 per hour for the plane of 100,000 pounds and the price increases with weight.[21]
+
+Non-aeronautical revenue is gained through things other than aircraft operations. It includes lease revenue from compatible land-use development, non-aeronautical building leases, retail and concession sales, rental car operations, parking and in-airport advertising.[22] Concession revenue is one big part of non-aeronautical revenue airports makes through duty free, bookstores, restaurants and money exchange.[20] Car parking is a growing source of revenue for airports, as more people use the parking facilities of the airport. O'Hare International Airport in Chicago charges $2 per hour for every car.[23]
+
+Airports are divided into landside and airside areas. The landside area is open to the public, while access to the airside area is tightly controlled. The airside area includes all parts of the airport around the aircraft, and the parts of the buildings that are accessible only to passengers and staff. Passengers and staff must be checked by security before being permitted to enter the airside area. Conversely, passengers arriving from an international flight must pass through border control and customs to access the landside area, where they can exit the airport. Many major airports will issue a secure keycard called an airside pass to employees, as some roles require employees to frequently move back and forth between landside and airside as part of their duties.
+
+A terminal is a building with passenger facilities. Small airports have one terminal. Large ones often have multiple terminals, though some large airports like Amsterdam Airport Schiphol still have one terminal. The terminal has a series of gates, which provide passengers with access to the plane.
+
+The following facilities are essential for departing passengers:
+
+The following facilities are essential for arriving passengers:
+
+For both sets of passengers, there must be a link between the passenger facilities and the aircraft, such as jet bridges or airstairs. There also needs to be a baggage handling system, to transport baggage from the baggage drop-off to departing planes, and from arriving planes to the baggage reclaim.
+
+The area where the aircraft park to load passengers and baggage is known as an apron or ramp (or incorrectly[24], "the tarmac").
+
+Airports with international flights have customs and immigration facilities. However, as some countries have agreements that allow travel between them without customs and immigrations, such facilities are not a definitive need for an international airport. International flights often require a higher level of physical security, although in recent years, many countries have adopted the same level of security for international and domestic travel.
+
+"Floating airports" are being designed which could be located out at sea and which would use designs such as pneumatic stabilized platform technology.
+
+Airport security normally requires baggage checks, metal screenings of individual persons, and rules against any object that could be used as a weapon. Since the September 11 attacks and the Real ID Act of 2005, airport security has dramatically increased and got tighter and stricter than ever before.
+
+Most major airports provide commercial outlets for products and services. Most of these companies, many of which are internationally known brands, are located within the departure areas. These include clothing boutiques and restaurants and in the US amounted to $4.2 billion in 2015.[25] Prices charged for items sold at these outlets are generally higher than those outside the airport. However, some airports now regulate costs to keep them comparable to "street prices". This term is misleading as prices often match the manufacturers' suggested retail price (MSRP) but are almost never discounted.[citation needed]
+
+Apart from major fast food chains, some airport restaurants offer regional cuisine specialties for those in transit so that they may sample local food or culture without leaving the airport.[26]
+
+Some airport structures include on-site hotels built within or attached to a terminal building. Airport hotels have grown popular due to their convenience for transient passengers and easy accessibility to the airport terminal. Many airport hotels also have agreements with airlines to provide overnight lodging for displaced passengers.
+
+Major airports in such countries as Russia and Japan offer miniature sleeping units within the airport that are available for rent by the hour. The smallest type is the capsule hotel popular in Japan. A slightly larger variety is known as a sleep box. An even larger type is provided by the company YOTEL.
+
+Airports may also contain premium and VIP services. The premium and VIP services may include express check-in and dedicated check-in counters.
+These services are usually reserved for first and business class passengers, premium frequent flyers, and members of the airline's clubs. Premium services may sometimes be open to passengers who are members of a different airline's frequent flyer program. This can sometimes be part of a reciprocal deal, as when multiple airlines are part of the same alliance, or as a ploy to attract premium customers away from rival airlines.
+
+Sometimes these premium services will be offered to a non-premium passenger if the airline has made a mistake in handling of the passenger, such as unreasonable delays or mishandling of checked baggage.
+
+Airline lounges frequently offer free or reduced cost food, as well as alcoholic and non-alcoholic beverages. Lounges themselves typically have seating, showers, quiet areas, televisions, computer, Wi-Fi and Internet access, and power outlets that passengers may use for their electronic equipment. Some airline lounges employ baristas, bartenders and gourmet chefs.
+
+Airlines sometimes operate multiple lounges within the one airport terminal allowing ultra-premium customers, such as first class customers, additional services, which are not available to other premium customers. Multiple lounges may also prevent overcrowding of the lounge facilities.
+
+In addition to people, airports move cargo around the clock. Cargo airlines often have their own on-site and adjacent infrastructure to transfer parcels between ground and air.
+
+Cargo Terminal Facilities are areas where international airports export cargo has to be stored after customs clearance and prior to loading on the aircraft. Similarly import cargo that is offloaded needs to be in bond before the consignee decides to take delivery. Areas have to be kept aside for examination of export and import cargo by the airport authorities. Designated areas or sheds may be given to airlines or freight forward ring agencies.
+
+Every cargo terminal has a landside and an airside. The landside is where the exporters and importers through either their agents or by themselves deliver or collect shipments while the airside is where loads are moved to or from the aircraft. In addition cargo terminals are divided into distinct areas – export, import and interline or transshipment.
+
+Airports require parking lots, for passengers who may leave the cars at the airport for a long period of time. Large airports will also have car-rental firms, taxi ranks, bus stops and sometimes a train station.
+
+Many large airports are located near railway trunk routes for seamless connection of multimodal transport, for instance Frankfurt Airport, Amsterdam Airport Schiphol, London Heathrow Airport, Tokyo Haneda Airport, Tokyo Narita Airport, London Gatwick Airport and London Stansted Airport. It is also common to connect an airport and a city with rapid transit, light rail lines or other non-road public transport systems. Some examples of this would include the AirTrain JFK at John F. Kennedy International Airport in New York, Link Light Rail that runs from the heart of downtown Seattle to Seattle–Tacoma International Airport, and the Silver Line T at Boston's Logan International Airport by the Massachusetts Bay Transportation Authority (MBTA). Such a connection lowers risk of missed flights due to traffic congestion. Large airports usually have access also through controlled-access highways ('freeways' or 'motorways') from which motor vehicles enter either the departure loop or the arrival loop.
+
+The distances passengers need to move within a large airport can be substantial. It is common for airports to provide moving walkways, buses, and rail transport systems. Some airports like Hartsfield–Jackson Atlanta International Airport and London Stansted Airport have a transit system that connects some of the gates to a main terminal. Airports with more than one terminal have a transit system to connect the terminals together, such as John F. Kennedy International Airport, Mexico City International Airport and London Gatwick Airport.
+
+There are three types of surface that aircraft operate on:
+
+Air traffic control (ATC) is the task of managing aircraft movements and making sure they are safe, orderly and expeditious. At the largest airports, air traffic control is a series of highly complex operations that requires managing frequent traffic that moves in all three dimensions.
+
+A "towered" or "controlled" airport has a control tower where the air traffic controllers are based. Pilots are required to maintain two-way radio communication with the controllers, and to acknowledge and comply with their instructions. A "non-towered" airport has no operating control tower and therefore two-way radio communications are not required, though it is good operating practice for pilots to transmit their intentions on the airport's common traffic advisory frequency (CTAF) for the benefit of other aircraft in the area. The CTAF may be a Universal Integrated Community (UNICOM), MULTICOM, Flight Service Station (FSS), or tower frequency.
+
+The majority of the world's airports are small facilities without a tower. Not all towered airports have 24/7 ATC operations. In those cases, non-towered procedures apply when the tower is not in use, such as at night. Non-towered airports come under area (en-route) control. Remote and virtual tower (RVT) is a system in which ATC is handled by controllers who are not present at the airport itself.
+
+Air traffic control responsibilities at airports are usually divided into at least two main areas: ground and tower, though a single controller may work both stations. The busiest airports may subdivide responsibilities further, with clearance delivery, apron control, and/or other specialized ATC stations.
+
+Ground control is responsible for directing all ground traffic in designated "movement areas", except the traffic on runways. This includes planes, baggage trains, snowplows, grass cutters, fuel trucks, stair trucks, airline food trucks, conveyor belt vehicles and other vehicles. Ground Control will instruct these vehicles on which taxiways to use, which runway they will use (in the case of planes), where they will park, and when it is safe to cross runways. When a plane is ready to takeoff it will be turned over to tower control. Conversely, after a plane has landed it will depart the runway and be "handed over" from Tower to Ground Control.
+
+Tower control is responsible for aircraft on the runway and in the controlled airspace immediately surrounding the airport. Tower controllers may use radar to locate an aircraft's position in 3D space, or they may rely on pilot position reports and visual observation. They coordinate the sequencing of aircraft in the traffic pattern and direct aircraft on how to safely join and leave the circuit. Aircraft which are only passing through the airspace must also contact tower control to be sure they remain clear of other traffic.
+
+At all airports the use of a traffic pattern (often called a traffic circuit outside the US) is possible. They may help to assure smooth traffic flow between departing and arriving aircraft. There is no technical need within modern commercial aviation for performing this pattern, provided there is no queue. And due to the so-called SLOT-times, the overall traffic planning tend to assure landing queues are avoided. If for instance an aircraft approaches runway 17 (which has a heading of approx. 170 degrees) from the north (coming from 360/0 degrees heading towards 180 degrees), the aircraft will land as fast as possible by just turning 10 degrees and follow the glidepath, without orbit the runway for visual reasons, whenever this is possible. For smaller piston engined airplanes at smaller airfields without ILS equipment, things are very different though.
+
+Generally, this pattern is a circuit consisting of five "legs" that form a rectangle (two legs and the runway form one side, with the remaining legs forming three more sides). Each leg is named (see diagram), and ATC directs pilots on how to join and leave the circuit. Traffic patterns are flown at one specific altitude, usually 800 or 1,000 ft (244 or 305 m) above ground level (AGL). Standard traffic patterns are left-handed, meaning all turns are made to the left. One of the main reason for this is that pilots sit on the left side of the airplane, and a Left-hand patterns improves their visibility of the airport and pattern. Right-handed patterns do exist, usually because of obstacles such as a mountain, or to reduce noise for local residents. The predetermined circuit helps traffic flow smoothly because all pilots know what to expect, and helps reduce the chance of a mid-air collision.
+
+At controlled airports, a circuit can be in place but is not normally used. Rather, aircraft (usually only commercial with long routes) request approach clearance while they are still hours away from the airport; the destination airport can then plan a queue of arrivals, and planes will be guided into one queue per active runway for a "straight-in" approach. While this system keeps the airspace free and is simpler for pilots, it requires detailed knowledge of how aircraft are planning to use the airport ahead of time and is therefore only possible with large commercial airliners on pre-scheduled flights. The system has recently become so advanced that controllers can predict whether an aircraft will be delayed on landing before it even takes off; that aircraft can then be delayed on the ground, rather than wasting expensive fuel waiting in the air.
+
+There are a number of aids, both visual and electronic, though not at all airports. A visual approach slope indicator (VASI) helps pilots fly the approach for landing. Some airports are equipped with a VHF omnidirectional range (VOR) to help pilots find the direction to the airport. VORs are often accompanied by a distance measuring equipment (DME) to determine the distance to the VOR. VORs are also located off airports, where they serve to provide airways for aircraft to navigate upon. In poor weather, pilots will use an instrument landing system (ILS) to find the runway and fly the correct approach, even if they cannot see the ground. The number of instrument approaches based on the use of the Global Positioning System (GPS) is rapidly increasing and may eventually become the primary means for instrument landings.
+
+Larger airports sometimes offer precision approach radar (PAR), but these systems are more common at military air bases than civilian airports. The aircraft's horizontal and vertical movement is tracked via radar, and the controller tells the pilot his position relative to the approach slope. Once the pilots can see the runway lights, they may continue with a visual landing.
+
+Airport guidance signs provide direction and information to taxiing aircraft and airport vehicles. Smaller aerodromes may have few or no signs, relying instead on diagrams and charts.
+
+Many airports have lighting that help guide planes using the runways and taxiways at night or in rain or fog.
+
+On runways, green lights indicate the beginning of the runway for landing, while red lights indicate the end of the runway. Runway edge lighting consists of white lights spaced out on both sides of the runway, indicating the edges. Some airports have more complicated lighting on the runways including lights that run down the centerline of the runway and lights that help indicate the approach (an approach lighting system, or ALS). Low-traffic airports may use pilot-controlled lighting to save electricity and staffing costs.
+
+Along taxiways, blue lights indicate the taxiway's edge, and some airports have embedded green lights that indicate the centerline.
+
+Weather observations at the airport are crucial to safe takeoffs and landings. In the US and Canada, the vast majority of airports, large and small, will either have some form of automated airport weather station, whether an AWOS, ASOS, or AWSS, a human observer or a combination of the two. These weather observations, predominantly in the METAR format, are available over the radio, through automatic terminal information service (ATIS), via the ATC or the flight service station.
+
+Planes take-off and land into the wind to achieve maximum performance. Because pilots need instantaneous information during landing, a windsock can also be kept in view of the runway. Aviation windsocks are made with lightweight material, withstand strong winds and some are lit up after dark or in foggy weather. Because visibility of windsocks is limited, often multiple glow-orange windsocks are placed on both sides of the runway.[27]
+
+Most airports have groundcrew handling the loading and unloading of passengers, crew, baggage and other services.[citation needed] Some groundcrew are linked to specific airlines operating at the airport.
+
+Among the vehicles that serve an airliner on the ground are:
+
+The length of time an aircraft remains on the ground in between consecutive flights is known as "turnaround time". Airlines pay great attention to minimizing turnaround times in an effort to keep aircraft use (flying time) high, with times scheduled as low as 25 minutes for jet aircraft operated by low-cost carriers on narrow-body aircraft.
+
+Like industrial equipment or facility management, airports require tailor-made maintenance management due to their complexity. With many tangible assets spread over a large area in different environments, these infrastructures must therefore effectively monitor these assets and store spare parts to maintain them at an optimal level of service.[28]
+
+To manage these airport assets, several solutions are competing for the market: CMMS (computerized maintenance management system) predominate, and mainly enable a company's maintenance activity to be monitored, planned, recorded and rationalized.[28]
+
+Aviation safety is an important concern in the operation of an airport, and almost every airfield includes equipment and procedures for handling emergency situations. Airport crash tender crews are equipped for dealing with airfield accidents, crew and passenger extractions, and the hazards of highly flammable aviation fuel. The crews are also trained to deal with situations such as bomb threats, hijacking, and terrorist activities.
+
+Hazards to aircraft include debris, nesting birds, and reduced friction levels due to environmental conditions such as ice, snow, or rain. Part of runway maintenance is airfield rubber removal which helps maintain friction levels. The fields must be kept clear of debris using cleaning equipment so that loose material does not become a projectile and enter an engine duct (see foreign object damage). In adverse weather conditions, ice and snow clearing equipment can be used to improve traction on the landing strip. For waiting aircraft, equipment is used to spray special deicing fluids on the wings.
+
+Many airports are built near open fields or wetlands. These tend to attract bird populations, which can pose a hazard to aircraft in the form of bird strikes. Airport crews often need to discourage birds from taking up residence.
+
+Some airports are located next to parks, golf courses, or other low-density uses of land. Other airports are located near densely populated urban or suburban areas.
+
+An airport can have areas where collisions between aircraft on the ground tend to occur. Records are kept of any incursions where aircraft or vehicles are in an inappropriate location, allowing these "hot spots" to be identified. These locations then undergo special attention by transportation authorities (such as the FAA in the US) and airport administrators.
+
+During the 1980s, a phenomenon known as microburst became a growing concern due to aircraft accidents caused by microburst wind shear, such as Delta Air Lines Flight 191. Microburst radar was developed as an aid to safety during landing, giving two to five minutes' warning to aircraft in the vicinity of the field of a microburst event.
+
+Some airfields now have a special surface known as soft concrete at the end of the runway (stopway or blastpad) that behaves somewhat like styrofoam, bringing the plane to a relatively rapid halt as the material disintegrates. These surfaces are useful when the runway is located next to a body of water or other hazard, and prevent the planes from overrunning the end of the field.
+
+Airports often have on-site firefighters to respond to emergencies. These use specialized vehicles, known as airport crash tenders.
+
+Aircraft noise is a major cause of noise disturbance to residents living near airports. Sleep can be affected if the airports operate night and early morning flights. Aircraft noise occurs not only from take-offs and landings, but also from ground operations including maintenance and testing of aircraft. Noise can have other health effects as well. Other noise and environmental concerns are vehicle traffic causing noise and pollution on roads leading to airport. [29]
+
+The construction of new airports or addition of runways to existing airports, is often resisted by local residents because of the effect on countryside, historical sites, and local flora and fauna. Due to the risk of collision between birds and aircraft, large airports undertake population control programs where they frighten or shoot birds.[citation needed]
+
+The construction of airports has been known to change local weather patterns. For example, because they often flatten out large areas, they can be susceptible to fog in areas where fog rarely forms. In addition, they generally replace trees and grass with pavement, they often change drainage patterns in agricultural areas, leading to more flooding, run-off and erosion in the surrounding land.[30][citation needed]
+
+Some of the airport administrations prepare and publish annual environmental reports to show how they consider these environmental concerns in airport management issues and how they protect environment from airport operations. These reports contain all environmental protection measures performed by airport administration in terms of water, air, soil and noise pollution, resource conservation and protection of natural life around the airport.
+
+A 2019 report from the Cooperative Research Programs of the US Transportation Research Board showed all airports have a role to play in advancing greenhouse gas (GHG) reduction initiatives. Small airports have demonstrated leadership by using their less complex organizational structure to implement newer technologies and to serve as a providing ground for their feasibility. Large airports have the economic stability and staff resources necessary to grow in-house expertise and fund comprehensive new programs.[31]
+
+A growing number of airports are installing solar photovoltaic arrays to offset their electricity use.[32][33] The National Renewable Energy Lab has shown this can be done safely.[34]
+
+The world's first airport to be fully powered by solar energy is located at Kochi, India. Another airport known for considering environmental concerns is Seymour Airport in the Galapagos Islands.
+
+An airbase, sometimes referred to as an air station or airfield, provides basing and support of military aircraft. Some airbases, known as military airports, provide facilities similar to their civilian counterparts. For example, RAF Brize Norton in the UK has a terminal which caters to passengers for the Royal Air Force's scheduled flights to the Falkland Islands. Some airbases are co-located with civilian airports, sharing the same ATC facilities, runways, taxiways and emergency services, but with separate terminals, parking areas and hangars. Bardufoss Airport, Bardufoss Air Station in Norway and Pune Airport in India are examples of this.
+
+An aircraft carrier is a warship that functions as a mobile airbase. Aircraft carriers allow a naval force to project air power without having to depend on local bases for land-based aircraft. After their development in World War I, aircraft carriers replaced the battleship as the centrepiece of a modern fleet during World War II.
+
+Most airports in the United States are designated "private-use airports" meaning that, whether publicly- or privately-owned, the airport is not open or available for use by the public (although use of the airport may be made available by invitation of the owner or manager).
+
+Airports are uniquely represented by their IATA airport code and ICAO airport code.
+
+Most airport names include the location. Many airport names honour a public figure, commonly a politician (e.g., Charles de Gaulle Airport, George Bush Intercontinental Airport, O.R. Tambo International Airport), a monarch (e.g. Chhatrapati Shivaji International Airport, King Shaka International Airport), a cultural leader (e.g. Liverpool John Lennon Airport, Leonardo da Vinci-Fiumicino Airport, Louis Armstrong New Orleans International Airport) or a prominent figure in aviation history of the region (e.g. Sydney Kingsford Smith Airport), sometimes even famous writers (e.g. Allama Iqbal International Airport) and explorers (e.g. Venice Marco Polo Airport).
+
+Some airports have unofficial names, possibly so widely circulated that its official name is little used or even known.[citation needed]
+
+Some airport names include the word "International" to indicate their ability to handle international air traffic. This includes some airports that do not have scheduled international airline services (e.g. Port Elizabeth International Airport).
+
+The earliest aircraft takeoff and landing sites were grassy fields.[35] The plane could approach at any angle that provided a favorable wind direction. A slight improvement was the dirt-only field, which eliminated the drag from grass. However, these functioned well only in dry conditions. Later, concrete surfaces would allow landings regardless of meteorological conditions.
+
+The title of "world's oldest airport" is disputed. College Park Airport in Maryland, US, established in 1909 by Wilbur Wright, is generally agreed to be the world's oldest continuously operating airfield,[36] although it serves only general aviation traffic.
+
+Beijing Nanyuan Airport in China, which was built to accommodate planes in 1904, and airships in 1907, opened in 1910.[37] It was in operation until September 2019. Pearson Field Airport in Vancouver, Washington, United States, was built to accommodate planes in 1905 and airships in 1911, and is still in use as of January 2020.[citation needed]
+
+Hamburg Airport opened in January 1911, making it the oldest commercial airport in the world which is still in operation. Bremen Airport opened in 1913 and remains in use, although it served as an American military field between 1945 and 1949. Amsterdam Airport Schiphol opened on September 16, 1916, as a military airfield, but has accepted civil aircraft only since December 17, 1920, allowing Sydney Airport—which started operations in January 1920—to claim to be one of the world's oldest continuously operating commercial airports.[38] Minneapolis-Saint Paul International Airport in the US opened in 1920 and has been in continuous commercial service since. It serves about 35,000,000 passengers each year and continues to expand, recently opening a new 11,000-foot (3,355 m) runway. Of the airports constructed during this early period in aviation, it is one of the largest and busiest that is still currently operating. Rome Ciampino Airport, opened 1916, is also a contender, as well as the Don Mueang International Airport near Bangkok, Thailand, which opened in 1914.
+Increased aircraft traffic during World War I led to the construction of landing fields. Aircraft had to approach these from certain directions and this led to the development of aids for directing the approach and landing slope.
+
+Following the war, some of these military airfields added civil facilities for handling passenger traffic. One of the earliest such fields was Paris – Le Bourget Airport at Le Bourget, near Paris. The first airport to operate scheduled international commercial services was Hounslow Heath Aerodrome in August 1919, but it was closed and supplanted by Croydon Airport in March 1920.[39] In 1922, the first permanent airport and commercial terminal solely for commercial aviation was opened at Flughafen Devau near what was then Königsberg, East Prussia. The airports of this era used a paved "apron", which permitted night flying as well as landing heavier aircraft.
+
+The first lighting used on an airport was during the latter part of the 1920s; in the 1930s approach lighting came into use. These indicated the proper direction and angle of descent. The colours and flash intervals of these lights became standardized under the International Civil Aviation Organization (ICAO). In the 1940s, the slope-line approach system was introduced. This consisted of two rows of lights that formed a funnel indicating an aircraft's position on the glideslope. Additional lights indicated incorrect altitude and direction.
+
+After World War II, airport design became more sophisticated. Passenger buildings were being grouped together in an island, with runways arranged in groups about the terminal. This arrangement permitted expansion of the facilities. But it also meant that passengers had to travel further to reach their plane.
+
+An improvement in the landing field was the introduction of grooves in the concrete surface. These run perpendicular to the direction of the landing aircraft and serve to draw off excess rainwater that could build up in front of the plane's wheels.
+
+Airport construction boomed during the 1960s with the increase in jet aircraft traffic. Runways were extended out to 3,000 m (9,800 ft). The fields were constructed out of reinforced concrete using a slip-form machine that produces a continuous slab with no disruptions along the length. The early 1960s also saw the introduction of jet bridge systems to modern airport terminals, an innovation which eliminated outdoor passenger boarding. These systems became commonplace in the United States by the 1970s.[citation needed]
+
+The malicious use of UAVs has led to the deployment of counter unmanned air system (C-UAS) technologies such as the Aaronia AARTOS which have been installed on major international airports[40][41].
+
+Airports have played major roles in films and television programs due to their very nature as a transport and international hub, and sometimes because of distinctive architectural features of particular airports. One such example of this is The Terminal, a film about a man who becomes permanently grounded in an airport terminal and must survive only on the food and shelter provided by the airport. They are also one of the major elements in movies such as The V.I.P.s, Speed, Airplane!, Airport (1970), Die Hard 2, Soul Plane, Jackie Brown, Get Shorty, Home Alone, Liar Liar, Passenger 57, Final Destination (2000), Unaccompanied Minors, Catch Me If You Can, Rendition and The Langoliers. They have also played important parts in television series like Lost, The Amazing Race, America's Next Top Model, Cycle 10 which have significant parts of their story set within airports. In other programmes and films, airports are merely indicative of journeys, e.g. Good Will Hunting.
+
+Several computer simulation games put the player in charge of an airport. These include the Airport Tycoon series, SimAirport and Airport CEO.
+
+Each national aviation authority has a source of information about airports in their country. This will contain information on airport elevation, airport lighting, runway information, communications facilities and frequencies, hours of operation, nearby NAVAIDs and contact information where prior arrangement for landing is necessary.
+
+Infraero is responsible for the airports in Brazil
+
+Lists:

en/600.html.txt

@@ -0,0 +1,116 @@
+
+
+An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917, but was not recognized as such.[4] The first confirmation of detection occurred in 1992. This was followed by the confirmation of a different planet, originally detected in 1988. As of 1 July 2020, there are 4,281 confirmed exoplanets in 3,163 systems, with 701 systems having more than one planet.[5]
+
+There are many methods of detecting exoplanets. Transit photometry and Doppler spectroscopy have found the most, but these methods suffer from a clear observational bias favoring the detection of planets near the star; thus, 85% of the exoplanets detected are inside the tidal locking zone.[6] In several cases, multiple planets have been observed around a star.[7] About 1 in 5 Sun-like stars[a] have an "Earth-sized"[b] planet in the habitable zone.[c][8][9] Assuming there are 200 billion stars in the Milky Way,[d] it can be hypothesized that there are 11 billion potentially habitable Earth-sized planets in the Milky Way, rising to 40 billion if planets orbiting the numerous red dwarfs are included.[10]
+
+The least massive planet known is Draugr (also known as PSR B1257+12 A or PSR B1257+12 b), which is about twice the mass of the Moon. The most massive planet listed on the NASA Exoplanet Archive is HR 2562 b,[11][12] about 30 times the mass of Jupiter, although according to some definitions of a planet (based on the nuclear fusion of deuterium[13]), it is too massive to be a planet and may be a brown dwarf instead. Known orbital times for exoplanets vary from a few hours (for those closest to their star) to thousands of years. Some exoplanets are so far away from the star that it is difficult to tell whether they are gravitationally bound to it. Almost all of the planets detected so far are within the Milky Way. There is evidence that extragalactic planets, exoplanets farther away in galaxies beyond the local Milky Way galaxy, may exist.[14][15] The nearest exoplanet is Proxima Centauri b, located 4.2 light-years (1.3 parsecs) from Earth and orbiting Proxima Centauri, the closest star to the Sun.[16]
+
+The discovery of exoplanets has intensified interest in the search for extraterrestrial life. There is special interest in planets that orbit in a star's habitable zone, where it is possible for liquid water, a prerequisite for life on Earth, to exist on the surface. The study of planetary habitability also considers a wide range of other factors in determining the suitability of a planet for hosting life.[17]
+
+Rogue planets do not orbit any star. Such objects are considered as a separate category of planet, especially if they are gas giants, which are often counted as sub-brown dwarfs.[18] The rogue planets in the Milky Way possibly number in the billions or more.[19][20]
+
+The convention for designating exoplanets is an extension of the system used for designating multiple-star systems as adopted by the International Astronomical Union (IAU). For exoplanets orbiting a single star, the IAU designation is formed by taking the designated or proper name of its parent star, and adding a lower case letter.[22] Letters are given in order of each planet's discovery around the parent star, so that the first planet discovered in a system is designated "b" (the parent star is considered to be "a") and later planets are given subsequent letters. If several planets in the same system are discovered at the same time, the closest one to the star gets the next letter, followed by the other planets in order of orbital size. A provisional IAU-sanctioned standard exists to accommodate the designation of circumbinary planets. A limited number of exoplanets have IAU-sanctioned proper names. Other naming systems exist.
+
+For centuries scientists, philosophers, and science fiction writers suspected that extrasolar planets existed, but there was no way of knowing whether they existed, how common they were, or how similar they might be to the planets of the Solar System. Various detection claims made in the nineteenth century were rejected by astronomers.
+
+The first evidence of a possible exoplanet, orbiting Van Maanen 2, was noted in 1917, but was not recognized as such. The astronomer Walter Sydney Adams, who later became director of the Mount Wilson Observatory, produced a spectrum of the star using Mount Wilson's 60-inch telescope. He interpreted the spectrum to be of an F-type main-sequence star, but it is now thought that such a spectrum could be caused by the residue of a nearby exoplanet that had been pulverized into dust by the gravity of the star, the resulting dust then falling onto the star.[4]
+
+The first suspected scientific detection of an exoplanet occurred in 1988. Shortly afterwards, the first confirmation of detection came in 1992, with the discovery of several terrestrial-mass planets orbiting the pulsar PSR B1257+12.[23] The first confirmation of an exoplanet orbiting a main-sequence star was made in 1995, when a giant planet was found in a four-day orbit around the nearby star 51 Pegasi. Some exoplanets have been imaged directly by telescopes, but the vast majority have been detected through indirect methods, such as the transit method and the radial-velocity method. In February 2018, researchers using the Chandra X-ray Observatory, combined with a planet detection technique called microlensing, found evidence of planets in a distant galaxy, stating "Some of these exoplanets are as (relatively) small as the moon, while others are as massive as Jupiter. Unlike Earth, most of the exoplanets are not tightly bound to stars, so they're actually wandering through space or loosely orbiting between stars. We can estimate that the number of planets in this [faraway] galaxy is more than a trillion.[24]
+
+This space we declare to be infinite... In it are an infinity of worlds of the same kind as our own.
+
+In the sixteenth century, the Italian philosopher Giordano Bruno, an early supporter of the Copernican theory that Earth and other planets orbit the Sun (heliocentrism), put forward the view that the fixed stars are similar to the Sun and are likewise accompanied by planets.
+
+In the eighteenth century, the same possibility was mentioned by Isaac Newton in the "General Scholium" that concludes his Principia. Making a comparison to the Sun's planets, he wrote "And if the fixed stars are the centres of similar systems, they will all be constructed according to a similar design and subject to the dominion of One."[26]
+
+In 1952, more than 40 years before the first hot Jupiter was discovered, Otto Struve wrote that there is no compelling reason why planets could not be much closer to their parent star than is the case in the Solar System, and proposed that Doppler spectroscopy and the transit method could detect super-Jupiters in short orbits.[27]
+
+Claims of exoplanet detections have been made since the nineteenth century. Some of the earliest involve the binary star 70 Ophiuchi. In 1855 William Stephen Jacob at the East India Company's Madras Observatory reported that orbital anomalies made it "highly probable" that there was a "planetary body" in this system.[28] In the 1890s, Thomas J. J. See of the University of Chicago and the United States Naval Observatory stated that the orbital anomalies proved the existence of a dark body in the 70 Ophiuchi system with a 36-year period around one of the stars.[29] However, Forest Ray Moulton published a paper proving that a three-body system with those orbital parameters would be highly unstable.[30] During the 1950s and 1960s, Peter van de Kamp of Swarthmore College made another prominent series of detection claims, this time for planets orbiting Barnard's Star.[31] Astronomers now generally regard all the early reports of detection as erroneous.[32]
+
+In 1991 Andrew Lyne, M. Bailes and S. L. Shemar claimed to have discovered a pulsar planet in orbit around PSR 1829-10, using pulsar timing variations.[33] The claim briefly received intense attention, but Lyne and his team soon retracted it.[34]
+
+As of 1 July 2020, a total of 4,281 confirmed exoplanets are listed in the Extrasolar Planets Encyclopedia, including a few that were confirmations of controversial claims from the late 1980s.[5]  The first published discovery to receive subsequent confirmation was made in 1988 by the Canadian astronomers Bruce Campbell, G. A. H. Walker, and Stephenson Yang of the University of Victoria and the University of British Columbia.[35] Although they were cautious about claiming a planetary detection, their radial-velocity observations suggested that a planet orbits the star Gamma Cephei. Partly because the observations were at the very limits of instrumental capabilities at the time, astronomers remained skeptical for several years about this and other similar observations. It was thought some of the apparent planets might instead have been brown dwarfs, objects intermediate in mass between planets and stars. In 1990, additional observations were published that supported the existence of the planet orbiting Gamma Cephei,[36] but subsequent work in 1992 again raised serious doubts.[37] Finally, in 2003, improved techniques allowed the planet's existence to be confirmed.[38]
+
+On 9 January 1992, radio astronomers Aleksander Wolszczan and Dale Frail announced the discovery of two planets orbiting the pulsar PSR 1257+12.[23] This discovery was confirmed, and is generally considered to be the first definitive detection of exoplanets. Follow-up observations solidified these results, and confirmation of a third planet in 1994 revived the topic in the popular press.[39] These pulsar planets are thought to have formed from the unusual remnants of the supernova that produced the pulsar, in a second round of planet formation, or else to be the remaining rocky cores of gas giants that somehow survived the supernova and then decayed into their current orbits.
+
+On 6 October 1995, Michel Mayor and Didier Queloz of the University of Geneva announced the first definitive detection of an exoplanet orbiting a main-sequence star, nearby G-type star 51 Pegasi.[40][41] This discovery, made at the Observatoire de Haute-Provence, ushered in the modern era of exoplanetary discovery, and was recognized by a share of the 2019 Nobel Prize in Physics. Technological advances, most notably in high-resolution spectroscopy, led to the rapid detection of many new exoplanets: astronomers could detect exoplanets indirectly by measuring their gravitational influence on the motion of their host stars. More extrasolar planets were later detected by observing the variation in a star's apparent luminosity as an orbiting planet transited in front of it.
+
+Initially, most known exoplanets were massive planets that orbited very close to their parent stars. Astronomers were surprised by these "hot Jupiters", because theories of planetary formation had indicated that giant planets should only form at large distances from stars. But eventually more planets of other sorts were found, and it is now clear that hot Jupiters make up the minority of exoplanets. In 1999, Upsilon Andromedae became the first main-sequence star known to have multiple planets.[42] Kepler-16 contains the first discovered planet that orbits around a binary main-sequence star system.[43]
+
+On 26 February 2014, NASA announced the discovery of 715 newly verified exoplanets around 305 stars by the Kepler Space Telescope. These exoplanets were checked using a statistical technique called "verification by multiplicity".[44][45][46] Before these results, most confirmed planets were gas giants comparable in size to Jupiter or larger because they are more easily detected, but the Kepler planets are mostly between the size of Neptune and the size of Earth.[44]
+
+On 23 July 2015, NASA announced Kepler-452b, a near-Earth-size planet orbiting the habitable zone of a G2-type star.[47]
+
+On 6 September 2018, NASA discovered an exoplanet about 145 light years away from Earth in the constellation Virgo.[48] This exoplanet, Wolf 503b, is twice the size of Earth and was discovered orbiting a type of star known as an "Orange Dwarf". Wolf 503b completes one orbit in as few as six days because it is very close to the star. Wolf 503b is the only exoplanet that large that can be found near the so-called Fulton gap. The Fulton gap, first noticed in 2017, is the observation that it is unusual to find planets within a certain mass range.[48] Under the Fulton gap studies, this opens up a new field for astronomers, who are still studying whether planets found in the Fulton gap are gaseous or rocky.[48]
+
+In January 2020, scientists announced the discovery of TOI 700 d, the first Earth-sized planet in the habitable zone detected by TESS.[49]
+
+As of January 2020, NASA's Kepler and TESS missions had identified 4374 planetary candidates yet to be confirmed,[50] several of them being nearly Earth-sized and located in the habitable zone, some around Sun-like stars.[51][52][53]
+
+About 97% of all the confirmed exoplanets have been discovered by indirect techniques of detection, mainly by radial velocity measurements and transit monitoring techniques.[57] Recently the techniques of singular optics have been applied in the search for exoplanets.[58]
+
+Planets may form within a few to tens (or more) of millions of years of their star forming.[59][60][61][62][63] 
+The planets of the Solar System can only be observed in their current state, but observations of different planetary systems of varying ages allows us to observe planets at different stages of evolution. Available observations range from young proto-planetary disks where planets are still forming[64] to planetary systems of over 10 Gyr old.[65] When planets form in a gaseous protoplanetary disk,[66] they accrete hydrogen/helium envelopes.[67][68] These envelopes cool and contract over time and, depending on the mass of the planet, some or all of the hydrogen/helium is eventually lost to space.[66] This means that even terrestrial planets may start off with large radii if they form early enough.[69][70][71] An example is Kepler-51b which has only about twice the mass of Earth but is almost the size of Saturn which is a hundred times the mass of Earth. Kepler-51b is quite young at a few hundred million years old.[72]
+
+There is at least one planet on average per star.[7]
+About 1 in 5 Sun-like stars[a] have an "Earth-sized"[b] planet in the habitable zone.[74]
+
+Most known exoplanets orbit stars roughly similar to the Sun, i.e. main-sequence stars of spectral categories F, G, or K. Lower-mass stars (red dwarfs, of spectral category M) are less likely to have planets massive enough to be detected by the radial-velocity method.[75][76] Despite this, several tens of planets around red dwarfs have been discovered by the Kepler spacecraft, which uses the transit method to detect smaller planets.
+
+Using data from Kepler, a correlation has been found between the metallicity of a star and the probability that the star host planets. Stars with higher metallicity are more likely to have planets, especially giant planets, than stars with lower metallicity.[77]
+
+Some planets orbit one member of a binary star system,[78] and several circumbinary planets have been discovered which orbit around both members of binary star. A few planets in triple star systems are known[79] and one in the quadruple system Kepler-64.
+
+In 2013 the color of an exoplanet was determined for the first time. The best-fit albedo measurements of HD 189733b suggest that it is deep dark blue.[80][81] Later that same year, the colors of several other exoplanets were determined, including GJ 504 b which visually has a magenta color,[82] and Kappa Andromedae b, which if seen up close would appear reddish in color.[83]
+Helium planets are expected to be white or grey in appearance.[84]
+
+The apparent brightness (apparent magnitude) of a planet depends on how far away the observer is, how reflective the planet is (albedo), and how much light the planet receives from its star, which depends on how far the planet is from the star and how bright the star is. So, a planet with a low albedo that is close to its star can appear brighter than a planet with high albedo that is far from the star.[85]
+
+The darkest known planet in terms of geometric albedo is TrES-2b, a hot Jupiter that reflects less than 1% of the light from its star, making it less reflective than coal or black acrylic paint. Hot Jupiters are expected to be quite dark due to sodium and potassium in their atmospheres but it is not known why TrES-2b is so dark—it could be due to an unknown chemical compound.[86][87][88]
+
+For gas giants, geometric albedo generally decreases with increasing metallicity or atmospheric temperature unless there are clouds to modify this effect. Increased cloud-column depth increases the albedo at optical wavelengths, but decreases it at some infrared wavelengths. Optical albedo increases with age, because older planets have higher cloud-column depths. Optical albedo decreases with increasing mass, because higher-mass giant planets have higher surface gravities, which produces lower cloud-column depths. Also, elliptical orbits can cause major fluctuations in atmospheric composition, which can have a significant effect.[89]
+
+There is more thermal emission than reflection at some near-infrared wavelengths for massive and/or young gas giants. So, although optical brightness is fully phase-dependent, this is not always the case in the near infrared.[89]
+
+Temperatures of gas giants reduce over time and with distance from their star. Lowering the temperature increases optical albedo even without clouds. At a sufficiently low temperature, water clouds form, which further increase optical albedo. At even lower temperatures ammonia clouds form, resulting in the highest albedos at most optical and near-infrared wavelengths.[89]
+
+In 2014, a magnetic field around HD 209458 b was inferred from the way hydrogen was evaporating from the planet. It is the first (indirect) detection of a magnetic field on an exoplanet. The magnetic field is estimated to be about one tenth as strong as Jupiter's.[90][91]
+
+Exoplanets magnetic fields may be detectable by their auroral radio emissions with sensitive enough radio telescopes such as LOFAR.[92][93] The radio emissions could enable determination of the rotation rate of the interior of an exoplanet, and may yield a more accurate way to measure exoplanet rotation than by examining the motion of clouds.[94]
+
+Earth's magnetic field results from its flowing liquid metallic core, but in massive super-Earths with high pressure, different compounds may form which do not match those created under terrestrial conditions. Compounds may form with greater viscosities and high melting temperatures which could prevent the interiors from separating into different layers and so result in undifferentiated coreless mantles. Forms of magnesium oxide such as MgSi3O12 could be a liquid metal at the pressures and temperatures found in super-Earths and could generate a magnetic field in the mantles of super-Earths.[95][96]
+
+Hot Jupiters have been observed to have a larger radius than expected. This could be caused by the interaction between the stellar wind and the planet's magnetosphere creating an electric current through the planet that heats it up causing it to expand. The more magnetically active a star is the greater the stellar wind and the larger the electric current leading to more heating and expansion of the planet. This theory matches the observation that stellar activity is correlated with inflated planetary radii.[97]
+
+In August 2018, scientists announced the transformation of gaseous deuterium into a liquid metallic form. This may help researchers better understand giant gas planets, such as Jupiter, Saturn and related exoplanets, since such planets are thought to contain a lot of liquid metallic hydrogen, which may be responsible for their observed powerful magnetic fields.[98][99]
+
+Although scientists previously announced that the magnetic fields of close-in exoplanets may cause increased stellar flares and starspots on their host stars, in 2019 this claim was demonstrated to be false in the HD 189733 system.  The failure to detect "star-planet interactions" in the well-studied HD 189733 system calls other related claims of the effect into question.[100]
+
+In 2019 the strength of the surface magnetic fields of 4 hot Jupiters were estimated and ranged between 20 and 120 gauss compared to Jupiter's surface magnetic field of 4.3 gauss.[101][102]
+
+In 2007, two independent teams of researchers came to opposing conclusions about the likelihood of plate tectonics on larger super-Earths[103][104] with one team saying that plate tectonics would be episodic or stagnant[105] and the other team saying that plate tectonics is very likely on super-Earths even if the planet is dry.[106]
+
+If super-Earths have more than 80 times as much water as Earth then they become ocean planets with all land completely submerged. However, if there is less water than this limit, then the deep water cycle will move enough water between the oceans and mantle to allow continents to exist.[107][108]
+
+Large surface temperature variations on 55 Cancri e have been attributed to possible volcanic activity releasing large clouds of dust which blanket the planet and block thermal emissions.[109][110]
+
+The star 1SWASP J140747.93-394542.6 is orbited by an object that is circled by a ring system much larger than Saturn's rings. However, the mass of the object is not known; it could be a brown dwarf or low-mass star instead of a planet.[111][112]
+
+The brightness of optical images of Fomalhaut b could be due to starlight reflecting off a circumplanetary ring system with a radius between 20 and 40 times that of Jupiter's radius, about the size of the orbits of the Galilean moons.[113]
+
+The rings of the Solar System's gas giants are aligned with their planet's equator. However, for exoplanets that orbit close to their star, tidal forces from the star would lead to the outermost rings of a planet being aligned with the planet's orbital plane around the star. A planet's innermost rings would still be aligned with the planet's equator so that if the planet has a tilted rotational axis, then the different alignments between the inner and outer rings would create a warped ring system.[114]
+
+In December 2013 a candidate exomoon of a rogue planet was announced.[115] On 3 October 2018, evidence suggesting a large exomoon orbiting Kepler-1625b was reported.[116]
+
+Atmospheres have been detected around several exoplanets. The first to be observed was HD 209458 b in 2001.[118]
+
+In May 2017, glints of light from Earth, seen as twinkling from an orbiting satellite a million miles away, were found to be reflected light from ice crystals in the atmosphere.[119][120] The technology used to determine this may be useful in studying the atmospheres of distant worlds, including those of exoplanets.
+
+KIC 12557548 b is a small rocky planet, very close to its star, that is evaporating and leaving a trailing tail of cloud and dust like a comet.[121] The dust could be ash erupting from volcanos and escaping due to the small planet's low surface-gravity, or it could be from metals that are vaporized by the high temperatures of being so close to the star with the metal vapor then condensing into dust.[122]
+
+In June 2015, scientists reported that the atmosphere of GJ 436 b was evaporating, resulting in a giant cloud around the planet and, due to radiation from the host star, a long trailing tail 14 million km (9 million mi) long.[123]
+
+Tidally locked planets in a 1:1 spin-orbit resonance would have their star always shining directly overhead on one spot which would be hot with the opposite hemisphere receiving no light and being freezing cold. Such a planet could resemble an eyeball with the hotspot being the pupil.[124] Planets with an eccentric orbit could be locked in other resonances. 3:2 and 5:2 resonances would result in a double-eyeball pattern with hotspots in both eastern and western hemispheres.[125] Planets with both an eccentric orbit and a tilted axis of rotation would have more complicated insolation patterns.[126]
+
+As more planets are discovered, the field of exoplanetology continues to grow into a deeper study of extrasolar worlds, and will ultimately tackle the prospect of life on planets beyond the Solar System.[57] At cosmic distances, life can only be detected if it is developed at a planetary scale and strongly modified the planetary environment, in such a way that the modifications cannot be explained by classical physico-chemical processes (out of equilibrium processes).[57] For example, molecular oxygen (O2) in the atmosphere of Earth is a result of photosynthesis by living plants and many kinds of microorganisms, so it can be used as an indication of life on exoplanets, although small amounts of oxygen could also be produced by non-biological means.[127] Furthermore, a potentially habitable planet must orbit a stable star at a distance within which planetary-mass objects with sufficient atmospheric pressure can support liquid water at their surfaces.[128][129]

en/6000.html.txt

@@ -0,0 +1,136 @@
+The cello (/ˈtʃɛloʊ/ CHEL-oh; plural celli or cellos) or violoncello (/ˌvaɪələnˈtʃɛloʊ/ VY-ə-lən-CHEL-oh;[1] Italian pronunciation: [vjolonˈtʃɛllo]) is a bowed (and occasionally plucked) string instrument of the violin family. Its four strings are usually tuned in perfect fifths: from low to high, C2, G2, D3 and A3. Each string is an octave lower than the viola's four strings. Music for the cello is generally written in the bass clef, with tenor clef and treble clef used for higher-range passages.
+
+Played by a cellist or violoncellist, it enjoys a large solo repertoire with and without accompaniment, as well as numerous concerti. As a solo instrument, the cello uses its whole range, from bass to soprano, and in chamber music such as string quartets and the orchestra's string section, it often plays the bass part, where it may be reinforced an octave lower by the double basses. Figured bass music of the Baroque-era typically assumes a cello, viola da gamba or bassoon as part of the basso continuo group alongside chordal instruments such as organ, harpsichord, lute or theorbo. Cellos are found in many other ensembles, from modern Chinese orchestras to cello rock bands.
+
+The name cello is derived from the ending of the Italian violoncello,[2] which means "little violone". Violone ("big viola") was a large-sized member of viol (viola da gamba) family or the violin (viola da braccio) family. The term "violone" today usually refers to the lowest-pitched instrument of the viols, a family of stringed instruments that went out of fashion around the end of the 17th century in most countries except England and, especially, France, where they survived another half-century before the louder violin family came into greater favour in that country as well. In modern symphony orchestras, it is the second largest stringed instrument (the double bass is the largest). Thus, the name "violoncello" contained both the augmentative "-one" ("big") and the diminutive "-cello" ("little"). By the turn of the 20th century, it had become common to shorten the name to 'cello, with the apostrophe indicating the missing stem.[3] It is now customary to use "cello" without apostrophe as the full designation.[3] Viol is derived from the root viola, which was derived from Medieval Latin vitula, meaning stringed instrument.
+
+Cellos are tuned in fifths, starting with C2 (two octaves below middle C), followed by G2, D3, and then A3. It is tuned in the same intervals as the viola, but an octave lower. Unlike the violin or viola but similar to the double bass, the cello has an endpin that rests on the floor to support the instrument's weight. The cello is most closely associated with European classical music. The instrument is a part of the standard orchestra, as part of the string section, and is the bass voice of the string quartet (although many composers give it a melodic role as well), as well as being part of many other chamber groups.
+
+Among the most well-known Baroque works for the cello are Johann Sebastian Bach's six unaccompanied Suites.  Other significant include Sonatas and Concertos by Vivaldi, and earlier works by Gabrieli, Geminiani, and Bononcini. As a basso continuo instrument basso continuo the cello may have been used in works by Francesca Caccini (1587–1641), Barbara Strozzi (1619–1677) with pieces such as Il primo libro di madrigali, per 2–5 voci e basso continuo, op. 1 and  Elisabeth Jacquet de La Guerre (1665–1729) who wrote six sonatas for violin and basso continuo.
+
+From the Classical era, the two concertos by Joseph Haydn in C major and D major stand out, as do the five sonatas for cello and pianoforte of Ludwig van Beethoven, which span the important three periods of his compositional evolution. Other outstanding examples include the three Concerti by Carl Philipp Emanuel Bach, Capricci by dall'Abaco, and Sonatas by Flackton, Boismortier, and Luigi Boccherini. A Divertimento for Piano, Clarinet, Viola and Cello is among the  surviving works by Duchess Anna Amalia of Brunswick-Wolfenbüttel (1739–1807).
+
+Well-known works of the Romantic era include the Robert Schumann Concerto, the Antonín Dvořák Concerto as well as the two sonatas and the Double Concerto by Johannes Brahms. A review of compositions for cello in the Romantic era must include the German composer Fanny Mendelssohn (1805–1847) who wrote the Fantasy in G minor for cello and piano[4] and a Capriccio in A-flat for cello.[5]
+
+Compositions from the late-19th and early 20th century include three cello sonatas (including the Cello Sonata in C Minor written in 1880) by Dame Ethel Smyth (1858–1944),  Edward Elgar's Cello Concerto in E minor, Claude Debussy's Sonata for Cello and Piano, and unaccompanied cello sonatas by Zoltán Kodály and Paul Hindemith.  Pieces including cello were written by American Music Center founder Marion Bauer (1882–1955)  (two trio sonatas for flute, cello and piano) and Ruth Crawford Seeger (1901–1953) (Diaphonic suite No. 2 for bassoon and cello).
+
+The cello's versatility made it popular with many composers in this era, such as Sergei Prokofiev, Dmitri Shostakovich, Benjamin Britten, György Ligeti, Witold Lutoslawski and Henri Dutilleux. Polish composer Grażyna Bacewicz (1909–1969) was writing for cello in the mid 20th century with Concerto No. 1 for Cello and Orchestra (1951), Concerto No. 2 for Cello and Orchestra (1963) and in 1964 composed her Quartet for four cellos.
+
+Well-known cellists from the 20th century include Jacqueline du Pré, Pablo Casals, Yo-Yo Ma,  Emanuel Feuermann, Guilhermina Suggia, Mstislav Rostropovich and Beatrice Harrison. Others include Raya Garbousova, Anner Bylsma, Zara Nelsova, Alfred Wallenstein, Han-Na Chang, Mischa Maisky, Hildur Gudnadottir, and Gregor Piatigorsky. See the comprehensive list of cellists here.
+
+In the 2010s, the instrument is found in popular music, but was more commonly used in 1970s pop and disco music.[citation needed] Today it is sometimes featured in pop and rock recordings, examples of which are noted later in this article. The cello has also appeared in major hip-hop and R & B performances, such as singers Rihanna and Ne-Yo's 2007 performance at the American Music Awards.[6] The instrument has also been modified for Indian classical music by Nancy Lesh and Saskia Rao-de Haas.[5]
+
+The violin family, including cello-sized instruments, emerged c. 1500 as family of instruments distinct from the viola da gamba family. The earliest depictions of the violin family, from northern Italy c. 1530, show three sizes of instruments, roughly corresponding to what we now call violins, violas, and cellos. Contrary to a popular misconception, the cello did not evolve from the viola da gamba, but existed alongside it for about two and a half centuries. The violin family is also known as the viola da braccio (meaning viola of the arm) family, a reference to the primary way the members of the family are held. This is to distinguish it from the viola da gamba (meaning viola of the leg) family, in which all the members are all held with the legs. The likely predecessors of the violin family include the lira da braccio and the rebec. The earliest surviving cellos are made by Andrea Amati, the first known member of the celebrated Amati family of luthiers.[7]
+
+The direct ancestor to the violoncello was the bass violin.[citation needed] Monteverdi referred to the instrument as "basso de viola da braccio" in Orfeo (1607). Although the first bass violin, possibly invented as early as 1538, was most likely inspired by the viol, it was created to be used in consort with the violin. The bass violin was actually often referred to as a "violone", or "large viola", as were the viols of the same period. Instruments that share features with both the bass violin and the viola da gamba appear in Italian art of the early 16th century.
+
+The invention of wire-wound strings (fine wire around a thin gut core), around 1660 in Bologna, allowed for a finer bass sound than was possible with purely gut strings on such a short body. Bolognese makers exploited this new technology to create the cello, a somewhat smaller instrument suitable for solo repertoire due to both the timbre of the instrument and the fact that the smaller size made it easier to play virtuosic passages.[citation needed] This instrument had disadvantages as well, however. The cello's light sound was not as suitable for church and ensemble playing, so it had to be doubled by organ, theorbo or violone.
+
+Around 1700, Italian players popularized the cello in northern Europe, although the bass violin (basse de violon) continued to be used for another two decades in France.[8] Many existing bass violins were literally cut down in size to convert them into cellos according to the smaller pattern developed by Stradivarius, who also made a number of old pattern large cellos (the 'Servais').[9] The sizes, names, and tunings of the cello varied widely by geography and time.[9] The size was not standardized until around 1750.
+
+Despite similarities to the viola da gamba, the cello is actually part of the viola da braccio family, meaning "viol of the arm", which includes, among others, the violin and viola. Though paintings like Bruegel's "The Rustic Wedding", and Jambe de Fer in his Epitome Musical suggest that the bass violin had alternate playing positions, these were short-lived and the more practical and ergonomic a gamba position eventually replaced them entirely.
+
+Baroque-era cellos differed from the modern instrument in several ways. The neck has a different form and angle, which matches the baroque bass-bar and stringing.[clarification needed] Modern cellos have an endpin at the bottom to support the instrument (and transmit some of the sound through the floor),[10] while Baroque cellos are held only by the calves of the player. Modern bows curve in and are held at the frog; Baroque bows curve out and are held closer to the bow's point of balance. Modern strings normally have a metal core, although some use a synthetic core; Baroque strings are made of gut, with the G and C strings wire-wound. Modern cellos often have fine-tuners connecting the strings to the tailpiece, which make it much easier to tune the instrument, but such pins are rendered ineffective by the flexibility of the gut strings used on Baroque cellos. Overall, the modern instrument has much higher string tension than the Baroque cello,[citation needed] resulting in a louder, more projecting tone, with fewer overtones.
+
+Few educational works specifically devoted to the cello existed before the 18th century, and those that do exist contain little value to the performer beyond simple accounts of instrumental technique. One of the earliest cello manuals is Michel Corrette's Méthode, thèorique et pratique pour apprendre en peu de temps le violoncelle dans sa perfection (Paris, 1741).[11]
+
+Cellos are part of the standard symphony orchestra, which usually includes eight to twelve cellists. The cello section, in standard orchestral seating, is located on stage left (the audience's right) in the front, opposite the first violin section. However, some orchestras and conductors prefer switching the positioning of the viola and cello sections. The principal cellist is the section leader, determining bowings for the section in conjunction with other string principals, playing solos and leading entrances (when the section begins to play its part). Principal players always sit closest to the audience.
+
+The cellos are a critical part of orchestral music; all symphonic works involve the cello section, and many pieces require cello soli or solos. Much of the time, cellos provide part of the low-register harmony for the orchestra. Often, the cello section plays the melody for a brief period, before returning to the harmony role. There are also cello concertos, which are orchestral pieces that feature a solo cellist accompanied by an entire orchestra.
+
+There are numerous cello concertos – where a solo cello is accompanied by an orchestra – notably 25 by Vivaldi, 12 by Boccherini, at least three by Haydn, three by C. P. E. Bach, two by Saint-Saëns, two by Dvořák, and one each by Robert Schumann, Lalo, and Elgar. There were also some composers who, while not otherwise cellists,[clarification needed] did write cello-specific repertoire, such as Nikolaus Kraft who wrote six cello concertos. Beethoven's Triple Concerto for Cello, Violin and Piano and Brahms' Double Concerto for Cello and Violin are also part of the concertante repertoire although in both cases the cello shares solo duties with at least one other instrument. Moreover, several composers wrote large-scale pieces for cello and orchestra, which are concertos in all but name. Some familiar "concertos" are Richard Strauss' tone poem Don Quixote, Tchaikovsky's Variations on a Rococo Theme, Bloch's Schelomo and Bruch's Kol Nidrei.
+
+In the 20th century, the cello repertoire grew immensely. This was partly due to the influence of virtuoso cellist Mstislav Rostropovich, who inspired, commissioned and premiered dozens of new works. Among these, Prokofiev's Symphony-Concerto, Britten's Cello Symphony, the concertos of Shostakovich and Lutosławski as well as Dutilleux's Tout un monde lointain... have already become part of the standard repertoire. Other major composers who wrote concertante works for him include Messiaen, Jolivet, Berio and Penderecki. In addition, Arnold, Barber, Glass, Hindemith, Honegger, Ligeti, Myaskovsky, Penderecki, Rodrigo, Villa-Lobos and Walton also wrote major concertos for other cellists, notably for Gaspar Cassadó, Aldo Parisot, Gregor Piatigorsky, Siegfried Palm and Julian Lloyd Webber.
+
+There are also many sonatas for cello and piano. Those written by Beethoven, Mendelssohn, Chopin, Brahms, Grieg, Rachmaninoff, Debussy, Fauré, Shostakovich, Prokofiev, Poulenc, Carter, and Britten are particularly well known.
+
+Other important pieces for cello and piano include Schumann's five Stücke im Volkston and transcriptions like Schubert's Arpeggione Sonata (originally for arpeggione and piano), César Franck's Cello Sonata (originally a violin sonata, transcribed by Jules Delsart with the composer's approval), Stravinsky's Suite italienne (transcribed by the composer – with Gregor Piatigorsky – from his ballet Pulcinella) and Bartók's first rhapsody (also transcribed by the composer, originally for violin and piano).
+
+There are pieces for cello solo, J. S. Bach's six Suites for Cello (which are among the best-known solo cello pieces), Kodály's Sonata for Solo Cello and Britten's three Cello Suites. Other notable examples include Hindemith's and Ysaÿe's Sonatas for Solo Cello, Dutilleux's Trois Strophes sur le Nom de Sacher, Berio's Les Mots Sont Allés, Cassadó's Suite for Solo Cello, Ligeti's Solo Sonata, Carter's two Figments and Xenakis' Nomos Alpha and Kottos.
+
+The cello is a member of the traditional string quartet as well as string quintets, sextet or trios and other mixed ensembles.
+There are also pieces written for two, three, four or more cellos; this type of ensemble is also called a "cello choir" and its sound is familiar from the introduction to Rossini's William Tell Overture as well as Zaccharia's prayer scene in Verdi's Nabucco. Tchaikovsky's 1812 Overture also starts with a cello ensemble, with four cellos playing the top lines and two violas playing the bass lines.  As a self-sufficient ensemble, its most famous repertoire is Heitor Villa-Lobos' first of his Bachianas Brasileiras for cello ensemble (the fifth is for soprano and 8 cellos). Other examples are Offenbach's cello duets, quartet, and sextet, Pärt's Fratres for eight cellos and Boulez' Messagesquisse for seven cellos, or even Villa-Lobos' rarely played Fantasia Concertante (1958) for 32 cellos. The 12 cellists of the Berlin Philharmonic Orchestra (or "the Twelve" as they have since taken to being called) specialize in this repertoire and have commissioned many works, including arrangements of well-known popular songs.
+
+The cello is less common in popular music than in classical music. Several bands feature a cello in their standard line-up, including Hoppy Jones of the Ink Spots and Joe Kwon of the Avett Brothers. The more common use in pop and rock is to bring the instrument in for a particular song. In the 1960s, artists such as the Beatles and Cher used the cello in popular music, in songs such as The Beatles' "Yesterday", "Eleanor Rigby" and "Strawberry Fields Forever", and Cher's "Bang Bang (My Baby Shot Me Down)". "Good Vibrations" by the Beach Boys includes the cello in its instrumental ensemble, which includes a number of instruments unusual for this sort of music. Bass guitarist Jack Bruce, who had  originally studied music on a performance scholarship for cello, played a prominent cello part in "As You Said" on Cream's Wheels of Fire studio album (1968).
+
+In the 1970s, the Electric Light Orchestra enjoyed great commercial success taking inspiration from so-called "Beatlesque" arrangements, adding the cello (and violin) to the standard rock combo line-up and in 1978 the UK based rock band, Colosseum II, collaborated with cellist Julian Lloyd Webber on the recording Variations. Most notably, Pink Floyd included a cello solo in their 1970 epic instrumental "Atom Heart Mother". Bass guitarist Mike Rutherford of Genesis was originally a cellist and included some cello parts in their Foxtrot album.
+
+Established non-traditional cello groups include Apocalyptica, a group of Finnish cellists best known for their versions of Metallica songs, Rasputina, a group of cellists committed to an intricate cello style intermingled with Gothic music, the Massive Violins, an ensemble of seven singing cellists known for their arrangements of rock, pop and classical hits, Von Cello, a cello fronted rock power trio, Break of Reality who mix elements of classical music with the more modern rock and metal genre, Cello Fury, a cello rock band that performs original rock/classical crossover music, and Jelloslave, a Minneapolis-based Cello duo with two percussionists. These groups are examples of a style that has become known as cello rock. The crossover string quartet bond also includes a cellist. Silenzium and Cellissimo Quartet are Russian (Novosibirsk) groups playing rock and metal and having more and more popularity in Siberia. Cold Fairyland from Shanghai, China is using a cello along a Pipa as the main solo instrument to create East meets West progressive (folk) rock.
+
+More recent bands using the cello are Clean Bandit, Aerosmith, The Auteurs, Nirvana, Oasis, Smashing Pumpkins, James, Talk Talk, Phillip Phillips, OneRepublic, and the baroque rock band Arcade Fire. An Atlanta-based trio, King Richard's Sunday Best, also uses a cellist in their lineup. So-called "chamber pop" artists like Kronos Quartet, The Vitamin String Quartet and Margot and the Nuclear So and So's have also recently made cello common in modern alternative rock. Heavy metal band System of a Down has also made use of the cello's rich sound. The indie rock band The Stiletto Formal are known for using a cello as a major staple of their sound, similarly, the indie rock band Canada employs two cello players in their lineup. The orch-rock group, The Polyphonic Spree, which has pioneered the use of stringed and symphonic instruments, employs the cello in very creative ways for many of their "psychedelic-esque" melodies. The first wave screamo band I Would Set Myself On Fire For You featured a cello as well as a viola to create a more folk-oriented sound. The band, Panic! at the Disco uses a cello in their song, "Build God, Then We'll Talk". The lead vocalist of the band, Brendon Urie, also did the recording of the cello solo. The Lumineers added cellist Nela Pekarek to the band in 2010. She plays cello, sings harmony and duets.
+
+In jazz, bassists Oscar Pettiford and Harry Babasin were among the first to use the cello as a solo instrument; both tuned their instrument in fourths, an octave above the double bass. Fred Katz (who was not a bassist) was one of the first notable jazz cellists to use the instrument's standard tuning and arco technique. Contemporary jazz cellists include Abdul Wadud, Diedre Murray, Ron Carter, Dave Holland, David Darling, Lucio Amanti, Akua Dixon, Ernst Reijseger, Fred Lonberg-Holm, Tom Cora and Erik Friedlander. Modern musical theatre pieces like Jason Robert Brown's The Last Five Years, Duncan Sheik's Spring Awakening, Adam Guettel's Floyd Collins, and Ricky Ian Gordon's My Life with Albertine use small string ensembles (including solo cellos) to a prominent extent.
+
+In Indian Classical music Saskia Rao-de Haas is a well established soloist as well as playing duets with her sitarist husband Pt. Shubhendra Rao. Other cellists performing Indian classical music are: Nancy Lesh (Dhrupad) and Anup Biswas. Both Rao and Lesh play the cello sitting cross-legged on the floor.
+
+The cello can also be used in bluegrass and folk music, with notable players including Ben Sollee of the Sparrow Quartet and the "Cajun cellist" Sean Grissom, as well as Vyvienne Long who, in addition to her own projects, has played for those of Damien Rice. Cellists such as Natalie Haas, Abby Newton and Liz Davis Maxfield have contributed significantly to the use of cello playing in Celtic folk music, often with the cello featured as a primary melodic instrument and employing the skills and techniques of traditional fiddle playing. Lindsay Mac is becoming well known for playing the cello like a guitar, with her cover of The Beatles' "Blackbird".
+
+The cello is typically made from carved wood, although other materials such as carbon fiber or aluminum may be used. A traditional cello has a spruce top, with maple for the back, sides, and neck. Other woods, such as poplar or willow, are sometimes used for the back and sides. Less expensive cellos frequently have tops and backs made of laminated wood. Laminated cellos are widely used in elementary and secondary school orchestras and youth orchestras, because they are much more durable than carved wood cellos (i.e., they are less likely to crack if bumped or dropped) and they are much less expensive.
+
+The top and back are traditionally hand-carved, though less expensive cellos are often machine-produced. The sides, or ribs, are made by heating the wood and bending it around forms. The cello body has a wide top bout, narrow middle formed by two C-bouts, and wide bottom bout, with the bridge and F holes just below the middle. The top and back of the cello has decorative border inlay known as purfling. While purfling is attractive, it is also functional: if the instrument is struck, the purfling can prevent cracking of the wood. A crack may form at the rim of the instrument, but spreads no further. Without purfling, cracks can spread up or down the top or back. Playing, traveling and the weather all affect the cello and can increase a crack if purfling is not in place. Less expensive instruments typically have painted purfling.[citation needed]
+
+In the late 1920s and early 1930s, the Aluminum Company of America (Alcoa) as well as German luthier G.A. Pfretzschner produced an unknown number of aluminum cellos (in addition to aluminum double basses and violins).[12] Cello manufacturer Luis & Clark constructs cellos from carbon fibre. Carbon fibre instruments are particularly suitable for outdoor playing because of the strength of the material and its resistance to humidity and temperature fluctuations. Luis & Clark has produced over 1000 cellos, some of which are owned by cellists such as Yo-Yo Ma[13] and Josephine van Lier.[14]
+
+Above the main body is the carved neck. The neck has a curved cross-section on its underside, which is where the player's thumb runs along the neck during playing. The neck leads to a pegbox and the scroll, which are all normally carved out of a single piece of wood, usually maple. The fingerboard is glued to the neck and extends over the body of the instrument. The fingerboard is given a curved shape, matching the curve on the bridge. Both the fingerboard and bridge need to be curved so that the performer can bow individual strings. If the cello were to have a flat fingerboard and bridge, as with a typical guitar, the performer would only be able to bow the leftmost and rightmost two strings, or bow all the strings. The performer would not be able to play the inner two strings alone.
+
+The nut is a raised piece of wood, fitted where the fingerboard meets the pegbox, in which the strings rest in shallow slots or grooves to keep them the correct distance apart. The pegbox houses four tapered tuning pegs, one for each string. The pegs are used to tune the cello by either tightening or loosening the string. The pegs are called "friction pegs", because they maintain their position by friction. The scroll is a traditional ornamental part of the cello and a feature of all other members of the violin family. Ebony is usually used for the tuning pegs, fingerboard, and nut, but other hardwoods, such as boxwood or rosewood, can be used. Black fittings on low-cost instruments are often made from inexpensive wood that has been blackened or "ebonized" to look like ebony, which is much harder and more expensive. Ebonised parts such as tuning pegs may crack or split, and the black surface of the fingerboard will eventually wear down to reveal the lighter wood underneath.
+
+Historically, cello strings had cores made out of catgut, which, despite its name is made from dried out sheep or goat intestines. Most modern strings used in the 2010s are wound with metallic materials like aluminum, titanium and chromium. Cellists may mix different types of strings on their instruments. The pitches of the open strings are C, G, D, and A (black note heads in the playing range figure above), unless alternative tuning (scordatura) is specified by the composer. Some composers (e.g. Ottorino Respighi in the final movement of ‘’The Pines of Rome’’) ask that the low C be tuned down to a B-flat so that the performer can play a different low note on the lowest open string.
+
+The tailpiece and endpin are found in the lower part of the cello. The tailpiece is the part of the cello to which the "ball ends" of the strings are attached by passing them through holes. The tailpiece is attached to the bottom of the cello. The tailpiece is traditionally made of ebony or another hard wood, but can also be made of plastic or steel on lower-cost instruments. It attaches the strings to the lower end of the cello, and can have one or more fine tuners. The fine tuners are used to make smaller adjustments to the pitch of the string. The fine tuners can increase the tension of each string (raising the pitch) or decrease the tension of the string (lowering the pitch). When the performer is putting on a new string, the fine tuner for that string is normally reset to a middle position, and then the peg is turned to bring the string up to pitch. The fine turners are used for subtle, minor adjustments to pitch, such as tuning a cello to the oboe's 440 Hz A note or to tune the cello to a piano.
+
+The endpin or spike is made of wood, metal or rigid carbon fibre and supports the cello in playing position. The endpin can be retracted into the hollow body of the instrument when the cello is being transported in its case. This makes the cello easier to move about. When the performer wishes to play the cello, the endpin is pulled out to lengthen it. The endpin is locked into the player's preferred length with a screw mechanism. The adjustable nature of endpins enables performers of different ages and body sizes to adjust the endpin length to suit them.  In the Baroque period the cello was held between the calves, as there was no endpin at that time. The endpin was "introduced by Adrien Servais c. 1845 to give the instrument greater stability".[15] Modern endpins are retractable and adjustable; older ones were removed when not in use. (The word "endpin" sometimes also refers to the button of wood located at this place in all instruments in the violin family, but this is usually called "tailpin".[16]) The sharp tip of the cello's endpin is sometimes capped with a rubber tip that protects the tip from dulling and prevents the cello from slipping on the floor. Many cellists use a rubber pad with a metal cup to keep the tip from slipping on the floor. A number of accessories to keep the endpin from slipping; these include ropes which attach to the chair leg and other devices.
+
+The bridge holds the strings above the cello and transfers their vibrations to the top of the instrument and the soundpost inside (see below). The bridge is not glued, but rather held in place by the tension of the strings. The bridge is usually positioned by the cross point of the "f-hole" (i.e., where the horizontal line occurs in the "f"). The f-holes, named for their shape, are located on either side of the bridge, and allow air to move in and out of the instrument as part of the sound-production process.  They probably actually stand for an old style medial S, for words related to Sound.[citation needed] The f-holes also act as access points to the interior of the cello for repairs or maintenance. Sometimes a small length of rubber hose containing a water-soaked sponge, called a Dampit, is inserted through the f-holes, and serves as a humidifier. This keeps the wood components of the cello from drying out.
+
+Internally, the cello has two important features: a bass bar, which is glued to the underside of the top of the instrument, and a round wooden sound post, a solid wooden cylinder which is wedged between the top and bottom plates. The bass bar, found under the bass foot of the bridge, serves to support the cello's top and distribute the vibrations from the strings to the body of the instrument. The sound post, found under the treble side of the bridge, connects the back and front of the cello. Like the bridge, the sound post is not glued, but is kept in place by the tensions of the bridge and strings. Together, the bass bar and sound post transfer the strings' vibrations to the top (front) of the instrument (and to a lesser extent the back), acting as a diaphragm to produce the instrument's sound.
+
+Cellos are constructed and repaired using hide glue, which is strong but reversible, allowing for disassembly when needed. Tops may be glued on with diluted glue, since some repairs call for the removal of the top. Theoretically, hide glue is weaker than the body's wood, so as the top or back shrinks side-to-side, the glue holding it lets go and the plate does not crack. Cellists repairing cracks in their cello do not use regular wood glue, because it cannot be steamed open when a repair has to be made by a luthier.
+
+Traditionally, bows are made from pernambuco or brazilwood. Both come from the same species of tree (Caesalpinia echinata), but pernambuco, used for higher-quality bows, is the heartwood of the tree and is darker in color than brazilwood (which is sometimes stained to compensate). Pernambuco is a heavy, resinous wood with great elasticity, which makes it an ideal wood for instrument bows. Horsehair is stretched out between the two ends of the bow. The taut horsehair is drawn over the strings to produce the cello's characteristic tone. A small knob is twisted to increase or decrease the tension of the horsehair. The tension on the bow is released when the instrument is not being used. The amount of tension a cellist puts on the bow hair depends on the preferences of the player, the style of music being played, and for students, the preferences of their teacher.
+
+Bows are also made from other materials, such as carbon fibre—stronger than wood—and fiberglass (often used to make inexpensive, lower-quality student bows). An average cello bow is 73 cm (29 in) long (shorter than a violin or viola bow) 3 cm (1.2 in) high (from the frog to the stick) and 1.5 cm (0.59 in) wide. The frog of a cello bow typically has a rounded corner like that of a viola bow, but is wider. A cello bow is roughly 10 g (0.35 oz) heavier than a viola bow, which in turn is roughly 10 g (0.35 oz) heavier than a violin bow.
+
+Bow hair is traditionally horsehair, though synthetic hair, in varying colors, is also used. Prior to playing, the musician tightens the bow by turning a screw to pull the frog (the part of the bow under the hand) back, and increase the tension of the hair. Rosin is applied by the player to make the hair sticky. Bows need to be re-haired periodically. Baroque style (1600–1750) cello bows were much thicker and were formed with a larger outward arch when compared to modern cello bows. The inward arch of a modern cello bow produces greater tension, which in turn gives off a louder sound.
+
+The cello bow has also been used to play electric guitars. Jimmy Page pioneered its application on tracks such as "Dazed and Confused". The post-rock Icelandic band Sigur Rós's lead singer often plays a guitar using a cello bow.
+
+In 1989, the German cellist Michael Bach began developing a curved bow, encouraged by John Cage, Dieter Schnebel, Mstislav Rostropovich and Luigi Colani: and since then many pieces have been composed especially for it. This curved bow (BACH.Bow) is a convex curved bow which, unlike the ordinary bow, renders possible polyphonic playing on the various strings of the instrument. The solo repertoire for violin and cello by J. S. Bach the BACH.Bow is particularly suited to it: and it was developed with this in mind, polyphonic playing being required, as well as monophonic.
+
+When a string is bowed or plucked, it vibrates and moves the air around it, producing sound waves. Because the string is quite thin, not much air is moved by the string itself, and consequently if the string was not mounted on a hollow body, the sound would be weak. In acoustic stringed instruments such as the cello, this lack of volume is solved by mounting the vibrating string on a larger hollow wooden body. The vibrations are transmitted to the larger body, which can move more air and produce a louder sound. Different designs of the instrument produces variations in the instrument’s vibrational patterns and thus changes the character of the sound produced.[18] A string’s fundamental pitch can be adjusted by changing its stiffness, which depends on tension and length. Tightening a string stiffens it by increasing both the outward forces along its length and the net forces it experiences during a distortion.[19] A cello can be tuned by adjusting the tension of its strings, by turning the tuning pegs mounted on its pegbox, and tension adjusters (fine tuners) on the tail piece.
+
+A string's length also affects its fundamental pitch. Shortening a string stiffens it by increasing its curvature during a distortion and subjecting it to larger net forces. Shortening the string also reduces its mass,  but does not alter the mass per unit length, and it is the latter ratio rather than the total mass which governs the frequency. The string vibrates in a standing wave whose speed of propagation is given by √T/m,  where T is the tension and m is the mass per unit length; there is a node at either end of the vibrating length, and thus the vibrating length l is half a wavelength.    Since the frequency of any wave is equal to the speed divided by the wavelength,  we have frequency = 1/2l × √T/m. (Note that some writers, including Muncaster (cited below) use the Greek letter μ in place of m.) Thus shortening a string increases the frequency, and thus the pitch. Because of this effect, you can raise and change the pitch of a string by pressing it against the fingerboard in the cello’s neck and effectively shortening it.[20] Likewise strings with less mass per unit length, if under the same tension, will have a higher frequency and thus higher pitch than more massive strings. This is a prime reason why the different strings on all string instruments have different fundamental pitches, with the lightest strings having the highest pitches.
+
+A played note of E or F-sharp has a frequency which is often very close to the natural resonating frequency of the body of the instrument,  and if the problem is not addressed this can set the body into near resonance.   This may cause an unpleasant sudden amplification of this pitch,  and additionally a loud beating sound results from the interference produced between these nearby frequencies; this is known as the “wolf tone” because it is an unpleasant growling sound. The wood resonance appears to be split into two frequencies by the driving force of the sounding string. These two periodic resonances beat with each other. This wolf tone must be eliminated or significantly reduced for the cello to play the nearby notes with a pleasant tone. This can be accomplished by modifying the cello front plate, attaching a wolf eliminator (a metal cylinder or a rubber cylinder encased in metal), or moving the sound post.[21]
+
+When a string is bowed or plucked to produce a note, the fundamental note is accompanied by higher frequency overtones. Each sound has a particular recipe of frequencies that combine to make the total sound.[22]
+
+Playing the cello is done while seated with the instrument supported on the floor by the endpin. The left hand fingertips stop the strings on the fingerboard, determining the pitch of the fingered note. The right hand plucks or bows the strings to sound the notes. The left hand fingertips stop the strings along their length, determining the pitch of each fingered note. Stopping the string closer to the bridge results in higher-pitched sound, because the vibrating string length has been shortened. In the neck positions (which use just less than half of the fingerboard, nearest the top of the instrument), the thumb rests on the back of the neck; in thumb position (a general name for notes on the remainder of the fingerboard) the thumb usually rests alongside the fingers on the string and the side of the thumb is used to play notes. The fingers are normally held curved with each knuckle bent, with the fingertips in contact with the string. If a finger is required on two (or more) strings at once to play perfect fifths (in double stops or chords) it is used flat. In slower, or more expressive playing, the contact point can move slightly away from the nail to the pad of the finger, allowing a fuller vibrato.
+
+Vibrato is a small oscillation in the pitch of a note, usually considered an expressive technique. Harmonics played on the cello fall into two classes; natural and artificial. Natural harmonics are produced by lightly touching (but not depressing) the string with the finger at certain places, and then bowing (or, rarely, plucking) the string. For example, the halfway point of the string will produce a harmonic that is one octave above the unfingered (open) string. Natural harmonics only produce notes that are part of the harmonic series on a particular string. Artificial harmonics (also called false harmonics or stopped harmonics), in which the player depresses the string fully with one finger while touching the same string lightly with another finger, can produce any note above middle C. 
+Glissando (Italian for "sliding") is an effect played by sliding the finger up or down the fingerboard without releasing the string. This causes the pitch to rise and fall smoothly, without separate, discernible steps.
+
+In cello playing, the bow is much like the breath of a wind instrument player. Arguably, it is the major factor in the expressiveness of the playing. The right hand holds the bow and controls the duration and character of the notes. The bow is drawn across the strings roughly halfway between the end of the fingerboard and the bridge, in a direction perpendicular to the strings. The bow is held and manipulated with all five fingers of the right hand, the thumb opposite the fingers and closer to the cellist's body. Tone production and volume of sound depend on a combination of several factors. The three most important ones are: bow speed, weight applied to the string, and point of contact of the bow hair with the string.
+
+Double stops involve the playing of two notes at the same time. Two strings are fingered simultaneously, and the bow is drawn so as to sound them both at once. In pizzicato playing, the string is plucked directly with the fingers or thumb. Pizzicato is often abbreviated as "pizz.". Position of the hand is slightly over the finger board and away from the bridge.
+
+A player using the col legno technique strikes or rubs the strings with the wood of the bow rather than the hair. In spiccato playing, the strings are not "drawn" by the bow hair but struck by it, while still retaining some horizontal motion, to generate a more percussive, crisp sound. In staccato, the player moves the bow a small distance and stops it on the string, making a short sound, the rest of the written duration being taken up by silence. 
+Legato is a technique where the notes are smoothly connected without accents or breaks. It is noted by a slur (curved line) above or below – depending on their position on the staff – the notes of the passage that is to be played legato.
+
+Sul ponticello ("on the bridge") refers to bowing closer to the bridge, while sul tasto ("on the fingerboard") calls for bowing nearer the end of the fingerboard. Sul tasto produces a more flute-like sound, with more emphasis on the fundamental frequency of the note, and softened overtones.
+
+Standard-sized cellos are referred to as "full-size" or "​4⁄4" but are also made in smaller (fractional) sizes, including ​7⁄8, ​3⁄4, ​1⁄2, ​1⁄4, ​1⁄8, ​1⁄10, and ​1⁄16. The fractions refer to volume rather than length, so a 1/2 size cello is much longer than half the length of a full size.  The smaller cellos are identical to standard cellos in construction, range, and usage, but are simply scaled-down for the benefit of children and shorter adults.
+
+Cellos in sizes larger than ​4⁄4 do exist, and cellists with unusually large hands may require such a non-standard instrument. Cellos made before approximately 1700 tended to be considerably larger than those made and commonly played today. Around 1680, changes in string-making technology made it possible to play lower-pitched notes on shorter strings. The cellos of Stradivari, for example, can be clearly divided into two models: the style made before 1702, characterized by larger instruments (of which only three exist in their original size and configuration), and the style made during and after 1707, when Stradivari began making smaller cellos. This later model is the design most commonly used by modern luthiers. The scale length of a ​4⁄4 cello is about 70 cm (27 1⁄2 in). The new size offered fuller tonal projection and greater range of expression. The instrument in this form was able to contribute to more pieces musically and offered the possibility of greater physical dexterity for the player to develop technique.[23]
+
+There are many accessories for the cello.
+
+Cellos are made by luthiers, specialists in building and repairing stringed instruments, ranging from guitars to violins. The following luthiers are notable for the cellos they have produced:
+
+A person who plays the cello is called a cellist. For a list of notable cellists, see the list of cellists and Category:Cellists.
+
+Specific instruments are famous (or become famous) for a variety of reasons. An instrument's notability may arise from its age, the fame of its maker, its physical appearance, its acoustic properties, and its use by notable performers. The most famous instruments are generally known for all of these things. The most highly prized instruments are now collector's items, and are priced beyond the reach of most musicians. These instruments are typically owned by some kind of organization or investment group, which may loan the instrument to a notable performer. (For example, the Davidov Stradivarius, which is currently in the possession of one of the most widely known living cellists, Yo-Yo Ma, is actually owned by the Vuitton Foundation.[25])
+
+Some notable cellos:
+
+La Mariée, a 1950 painting by Marc Chagall which is prominently featured in the 1999 film Notting Hill, portrays a goat playing a cello.

en/6001.html.txt

@@ -0,0 +1,136 @@
+The cello (/ˈtʃɛloʊ/ CHEL-oh; plural celli or cellos) or violoncello (/ˌvaɪələnˈtʃɛloʊ/ VY-ə-lən-CHEL-oh;[1] Italian pronunciation: [vjolonˈtʃɛllo]) is a bowed (and occasionally plucked) string instrument of the violin family. Its four strings are usually tuned in perfect fifths: from low to high, C2, G2, D3 and A3. Each string is an octave lower than the viola's four strings. Music for the cello is generally written in the bass clef, with tenor clef and treble clef used for higher-range passages.
+
+Played by a cellist or violoncellist, it enjoys a large solo repertoire with and without accompaniment, as well as numerous concerti. As a solo instrument, the cello uses its whole range, from bass to soprano, and in chamber music such as string quartets and the orchestra's string section, it often plays the bass part, where it may be reinforced an octave lower by the double basses. Figured bass music of the Baroque-era typically assumes a cello, viola da gamba or bassoon as part of the basso continuo group alongside chordal instruments such as organ, harpsichord, lute or theorbo. Cellos are found in many other ensembles, from modern Chinese orchestras to cello rock bands.
+
+The name cello is derived from the ending of the Italian violoncello,[2] which means "little violone". Violone ("big viola") was a large-sized member of viol (viola da gamba) family or the violin (viola da braccio) family. The term "violone" today usually refers to the lowest-pitched instrument of the viols, a family of stringed instruments that went out of fashion around the end of the 17th century in most countries except England and, especially, France, where they survived another half-century before the louder violin family came into greater favour in that country as well. In modern symphony orchestras, it is the second largest stringed instrument (the double bass is the largest). Thus, the name "violoncello" contained both the augmentative "-one" ("big") and the diminutive "-cello" ("little"). By the turn of the 20th century, it had become common to shorten the name to 'cello, with the apostrophe indicating the missing stem.[3] It is now customary to use "cello" without apostrophe as the full designation.[3] Viol is derived from the root viola, which was derived from Medieval Latin vitula, meaning stringed instrument.
+
+Cellos are tuned in fifths, starting with C2 (two octaves below middle C), followed by G2, D3, and then A3. It is tuned in the same intervals as the viola, but an octave lower. Unlike the violin or viola but similar to the double bass, the cello has an endpin that rests on the floor to support the instrument's weight. The cello is most closely associated with European classical music. The instrument is a part of the standard orchestra, as part of the string section, and is the bass voice of the string quartet (although many composers give it a melodic role as well), as well as being part of many other chamber groups.
+
+Among the most well-known Baroque works for the cello are Johann Sebastian Bach's six unaccompanied Suites.  Other significant include Sonatas and Concertos by Vivaldi, and earlier works by Gabrieli, Geminiani, and Bononcini. As a basso continuo instrument basso continuo the cello may have been used in works by Francesca Caccini (1587–1641), Barbara Strozzi (1619–1677) with pieces such as Il primo libro di madrigali, per 2–5 voci e basso continuo, op. 1 and  Elisabeth Jacquet de La Guerre (1665–1729) who wrote six sonatas for violin and basso continuo.
+
+From the Classical era, the two concertos by Joseph Haydn in C major and D major stand out, as do the five sonatas for cello and pianoforte of Ludwig van Beethoven, which span the important three periods of his compositional evolution. Other outstanding examples include the three Concerti by Carl Philipp Emanuel Bach, Capricci by dall'Abaco, and Sonatas by Flackton, Boismortier, and Luigi Boccherini. A Divertimento for Piano, Clarinet, Viola and Cello is among the  surviving works by Duchess Anna Amalia of Brunswick-Wolfenbüttel (1739–1807).
+
+Well-known works of the Romantic era include the Robert Schumann Concerto, the Antonín Dvořák Concerto as well as the two sonatas and the Double Concerto by Johannes Brahms. A review of compositions for cello in the Romantic era must include the German composer Fanny Mendelssohn (1805–1847) who wrote the Fantasy in G minor for cello and piano[4] and a Capriccio in A-flat for cello.[5]
+
+Compositions from the late-19th and early 20th century include three cello sonatas (including the Cello Sonata in C Minor written in 1880) by Dame Ethel Smyth (1858–1944),  Edward Elgar's Cello Concerto in E minor, Claude Debussy's Sonata for Cello and Piano, and unaccompanied cello sonatas by Zoltán Kodály and Paul Hindemith.  Pieces including cello were written by American Music Center founder Marion Bauer (1882–1955)  (two trio sonatas for flute, cello and piano) and Ruth Crawford Seeger (1901–1953) (Diaphonic suite No. 2 for bassoon and cello).
+
+The cello's versatility made it popular with many composers in this era, such as Sergei Prokofiev, Dmitri Shostakovich, Benjamin Britten, György Ligeti, Witold Lutoslawski and Henri Dutilleux. Polish composer Grażyna Bacewicz (1909–1969) was writing for cello in the mid 20th century with Concerto No. 1 for Cello and Orchestra (1951), Concerto No. 2 for Cello and Orchestra (1963) and in 1964 composed her Quartet for four cellos.
+
+Well-known cellists from the 20th century include Jacqueline du Pré, Pablo Casals, Yo-Yo Ma,  Emanuel Feuermann, Guilhermina Suggia, Mstislav Rostropovich and Beatrice Harrison. Others include Raya Garbousova, Anner Bylsma, Zara Nelsova, Alfred Wallenstein, Han-Na Chang, Mischa Maisky, Hildur Gudnadottir, and Gregor Piatigorsky. See the comprehensive list of cellists here.
+
+In the 2010s, the instrument is found in popular music, but was more commonly used in 1970s pop and disco music.[citation needed] Today it is sometimes featured in pop and rock recordings, examples of which are noted later in this article. The cello has also appeared in major hip-hop and R & B performances, such as singers Rihanna and Ne-Yo's 2007 performance at the American Music Awards.[6] The instrument has also been modified for Indian classical music by Nancy Lesh and Saskia Rao-de Haas.[5]
+
+The violin family, including cello-sized instruments, emerged c. 1500 as family of instruments distinct from the viola da gamba family. The earliest depictions of the violin family, from northern Italy c. 1530, show three sizes of instruments, roughly corresponding to what we now call violins, violas, and cellos. Contrary to a popular misconception, the cello did not evolve from the viola da gamba, but existed alongside it for about two and a half centuries. The violin family is also known as the viola da braccio (meaning viola of the arm) family, a reference to the primary way the members of the family are held. This is to distinguish it from the viola da gamba (meaning viola of the leg) family, in which all the members are all held with the legs. The likely predecessors of the violin family include the lira da braccio and the rebec. The earliest surviving cellos are made by Andrea Amati, the first known member of the celebrated Amati family of luthiers.[7]
+
+The direct ancestor to the violoncello was the bass violin.[citation needed] Monteverdi referred to the instrument as "basso de viola da braccio" in Orfeo (1607). Although the first bass violin, possibly invented as early as 1538, was most likely inspired by the viol, it was created to be used in consort with the violin. The bass violin was actually often referred to as a "violone", or "large viola", as were the viols of the same period. Instruments that share features with both the bass violin and the viola da gamba appear in Italian art of the early 16th century.
+
+The invention of wire-wound strings (fine wire around a thin gut core), around 1660 in Bologna, allowed for a finer bass sound than was possible with purely gut strings on such a short body. Bolognese makers exploited this new technology to create the cello, a somewhat smaller instrument suitable for solo repertoire due to both the timbre of the instrument and the fact that the smaller size made it easier to play virtuosic passages.[citation needed] This instrument had disadvantages as well, however. The cello's light sound was not as suitable for church and ensemble playing, so it had to be doubled by organ, theorbo or violone.
+
+Around 1700, Italian players popularized the cello in northern Europe, although the bass violin (basse de violon) continued to be used for another two decades in France.[8] Many existing bass violins were literally cut down in size to convert them into cellos according to the smaller pattern developed by Stradivarius, who also made a number of old pattern large cellos (the 'Servais').[9] The sizes, names, and tunings of the cello varied widely by geography and time.[9] The size was not standardized until around 1750.
+
+Despite similarities to the viola da gamba, the cello is actually part of the viola da braccio family, meaning "viol of the arm", which includes, among others, the violin and viola. Though paintings like Bruegel's "The Rustic Wedding", and Jambe de Fer in his Epitome Musical suggest that the bass violin had alternate playing positions, these were short-lived and the more practical and ergonomic a gamba position eventually replaced them entirely.
+
+Baroque-era cellos differed from the modern instrument in several ways. The neck has a different form and angle, which matches the baroque bass-bar and stringing.[clarification needed] Modern cellos have an endpin at the bottom to support the instrument (and transmit some of the sound through the floor),[10] while Baroque cellos are held only by the calves of the player. Modern bows curve in and are held at the frog; Baroque bows curve out and are held closer to the bow's point of balance. Modern strings normally have a metal core, although some use a synthetic core; Baroque strings are made of gut, with the G and C strings wire-wound. Modern cellos often have fine-tuners connecting the strings to the tailpiece, which make it much easier to tune the instrument, but such pins are rendered ineffective by the flexibility of the gut strings used on Baroque cellos. Overall, the modern instrument has much higher string tension than the Baroque cello,[citation needed] resulting in a louder, more projecting tone, with fewer overtones.
+
+Few educational works specifically devoted to the cello existed before the 18th century, and those that do exist contain little value to the performer beyond simple accounts of instrumental technique. One of the earliest cello manuals is Michel Corrette's Méthode, thèorique et pratique pour apprendre en peu de temps le violoncelle dans sa perfection (Paris, 1741).[11]
+
+Cellos are part of the standard symphony orchestra, which usually includes eight to twelve cellists. The cello section, in standard orchestral seating, is located on stage left (the audience's right) in the front, opposite the first violin section. However, some orchestras and conductors prefer switching the positioning of the viola and cello sections. The principal cellist is the section leader, determining bowings for the section in conjunction with other string principals, playing solos and leading entrances (when the section begins to play its part). Principal players always sit closest to the audience.
+
+The cellos are a critical part of orchestral music; all symphonic works involve the cello section, and many pieces require cello soli or solos. Much of the time, cellos provide part of the low-register harmony for the orchestra. Often, the cello section plays the melody for a brief period, before returning to the harmony role. There are also cello concertos, which are orchestral pieces that feature a solo cellist accompanied by an entire orchestra.
+
+There are numerous cello concertos – where a solo cello is accompanied by an orchestra – notably 25 by Vivaldi, 12 by Boccherini, at least three by Haydn, three by C. P. E. Bach, two by Saint-Saëns, two by Dvořák, and one each by Robert Schumann, Lalo, and Elgar. There were also some composers who, while not otherwise cellists,[clarification needed] did write cello-specific repertoire, such as Nikolaus Kraft who wrote six cello concertos. Beethoven's Triple Concerto for Cello, Violin and Piano and Brahms' Double Concerto for Cello and Violin are also part of the concertante repertoire although in both cases the cello shares solo duties with at least one other instrument. Moreover, several composers wrote large-scale pieces for cello and orchestra, which are concertos in all but name. Some familiar "concertos" are Richard Strauss' tone poem Don Quixote, Tchaikovsky's Variations on a Rococo Theme, Bloch's Schelomo and Bruch's Kol Nidrei.
+
+In the 20th century, the cello repertoire grew immensely. This was partly due to the influence of virtuoso cellist Mstislav Rostropovich, who inspired, commissioned and premiered dozens of new works. Among these, Prokofiev's Symphony-Concerto, Britten's Cello Symphony, the concertos of Shostakovich and Lutosławski as well as Dutilleux's Tout un monde lointain... have already become part of the standard repertoire. Other major composers who wrote concertante works for him include Messiaen, Jolivet, Berio and Penderecki. In addition, Arnold, Barber, Glass, Hindemith, Honegger, Ligeti, Myaskovsky, Penderecki, Rodrigo, Villa-Lobos and Walton also wrote major concertos for other cellists, notably for Gaspar Cassadó, Aldo Parisot, Gregor Piatigorsky, Siegfried Palm and Julian Lloyd Webber.
+
+There are also many sonatas for cello and piano. Those written by Beethoven, Mendelssohn, Chopin, Brahms, Grieg, Rachmaninoff, Debussy, Fauré, Shostakovich, Prokofiev, Poulenc, Carter, and Britten are particularly well known.
+
+Other important pieces for cello and piano include Schumann's five Stücke im Volkston and transcriptions like Schubert's Arpeggione Sonata (originally for arpeggione and piano), César Franck's Cello Sonata (originally a violin sonata, transcribed by Jules Delsart with the composer's approval), Stravinsky's Suite italienne (transcribed by the composer – with Gregor Piatigorsky – from his ballet Pulcinella) and Bartók's first rhapsody (also transcribed by the composer, originally for violin and piano).
+
+There are pieces for cello solo, J. S. Bach's six Suites for Cello (which are among the best-known solo cello pieces), Kodály's Sonata for Solo Cello and Britten's three Cello Suites. Other notable examples include Hindemith's and Ysaÿe's Sonatas for Solo Cello, Dutilleux's Trois Strophes sur le Nom de Sacher, Berio's Les Mots Sont Allés, Cassadó's Suite for Solo Cello, Ligeti's Solo Sonata, Carter's two Figments and Xenakis' Nomos Alpha and Kottos.
+
+The cello is a member of the traditional string quartet as well as string quintets, sextet or trios and other mixed ensembles.
+There are also pieces written for two, three, four or more cellos; this type of ensemble is also called a "cello choir" and its sound is familiar from the introduction to Rossini's William Tell Overture as well as Zaccharia's prayer scene in Verdi's Nabucco. Tchaikovsky's 1812 Overture also starts with a cello ensemble, with four cellos playing the top lines and two violas playing the bass lines.  As a self-sufficient ensemble, its most famous repertoire is Heitor Villa-Lobos' first of his Bachianas Brasileiras for cello ensemble (the fifth is for soprano and 8 cellos). Other examples are Offenbach's cello duets, quartet, and sextet, Pärt's Fratres for eight cellos and Boulez' Messagesquisse for seven cellos, or even Villa-Lobos' rarely played Fantasia Concertante (1958) for 32 cellos. The 12 cellists of the Berlin Philharmonic Orchestra (or "the Twelve" as they have since taken to being called) specialize in this repertoire and have commissioned many works, including arrangements of well-known popular songs.
+
+The cello is less common in popular music than in classical music. Several bands feature a cello in their standard line-up, including Hoppy Jones of the Ink Spots and Joe Kwon of the Avett Brothers. The more common use in pop and rock is to bring the instrument in for a particular song. In the 1960s, artists such as the Beatles and Cher used the cello in popular music, in songs such as The Beatles' "Yesterday", "Eleanor Rigby" and "Strawberry Fields Forever", and Cher's "Bang Bang (My Baby Shot Me Down)". "Good Vibrations" by the Beach Boys includes the cello in its instrumental ensemble, which includes a number of instruments unusual for this sort of music. Bass guitarist Jack Bruce, who had  originally studied music on a performance scholarship for cello, played a prominent cello part in "As You Said" on Cream's Wheels of Fire studio album (1968).
+
+In the 1970s, the Electric Light Orchestra enjoyed great commercial success taking inspiration from so-called "Beatlesque" arrangements, adding the cello (and violin) to the standard rock combo line-up and in 1978 the UK based rock band, Colosseum II, collaborated with cellist Julian Lloyd Webber on the recording Variations. Most notably, Pink Floyd included a cello solo in their 1970 epic instrumental "Atom Heart Mother". Bass guitarist Mike Rutherford of Genesis was originally a cellist and included some cello parts in their Foxtrot album.
+
+Established non-traditional cello groups include Apocalyptica, a group of Finnish cellists best known for their versions of Metallica songs, Rasputina, a group of cellists committed to an intricate cello style intermingled with Gothic music, the Massive Violins, an ensemble of seven singing cellists known for their arrangements of rock, pop and classical hits, Von Cello, a cello fronted rock power trio, Break of Reality who mix elements of classical music with the more modern rock and metal genre, Cello Fury, a cello rock band that performs original rock/classical crossover music, and Jelloslave, a Minneapolis-based Cello duo with two percussionists. These groups are examples of a style that has become known as cello rock. The crossover string quartet bond also includes a cellist. Silenzium and Cellissimo Quartet are Russian (Novosibirsk) groups playing rock and metal and having more and more popularity in Siberia. Cold Fairyland from Shanghai, China is using a cello along a Pipa as the main solo instrument to create East meets West progressive (folk) rock.
+
+More recent bands using the cello are Clean Bandit, Aerosmith, The Auteurs, Nirvana, Oasis, Smashing Pumpkins, James, Talk Talk, Phillip Phillips, OneRepublic, and the baroque rock band Arcade Fire. An Atlanta-based trio, King Richard's Sunday Best, also uses a cellist in their lineup. So-called "chamber pop" artists like Kronos Quartet, The Vitamin String Quartet and Margot and the Nuclear So and So's have also recently made cello common in modern alternative rock. Heavy metal band System of a Down has also made use of the cello's rich sound. The indie rock band The Stiletto Formal are known for using a cello as a major staple of their sound, similarly, the indie rock band Canada employs two cello players in their lineup. The orch-rock group, The Polyphonic Spree, which has pioneered the use of stringed and symphonic instruments, employs the cello in very creative ways for many of their "psychedelic-esque" melodies. The first wave screamo band I Would Set Myself On Fire For You featured a cello as well as a viola to create a more folk-oriented sound. The band, Panic! at the Disco uses a cello in their song, "Build God, Then We'll Talk". The lead vocalist of the band, Brendon Urie, also did the recording of the cello solo. The Lumineers added cellist Nela Pekarek to the band in 2010. She plays cello, sings harmony and duets.
+
+In jazz, bassists Oscar Pettiford and Harry Babasin were among the first to use the cello as a solo instrument; both tuned their instrument in fourths, an octave above the double bass. Fred Katz (who was not a bassist) was one of the first notable jazz cellists to use the instrument's standard tuning and arco technique. Contemporary jazz cellists include Abdul Wadud, Diedre Murray, Ron Carter, Dave Holland, David Darling, Lucio Amanti, Akua Dixon, Ernst Reijseger, Fred Lonberg-Holm, Tom Cora and Erik Friedlander. Modern musical theatre pieces like Jason Robert Brown's The Last Five Years, Duncan Sheik's Spring Awakening, Adam Guettel's Floyd Collins, and Ricky Ian Gordon's My Life with Albertine use small string ensembles (including solo cellos) to a prominent extent.
+
+In Indian Classical music Saskia Rao-de Haas is a well established soloist as well as playing duets with her sitarist husband Pt. Shubhendra Rao. Other cellists performing Indian classical music are: Nancy Lesh (Dhrupad) and Anup Biswas. Both Rao and Lesh play the cello sitting cross-legged on the floor.
+
+The cello can also be used in bluegrass and folk music, with notable players including Ben Sollee of the Sparrow Quartet and the "Cajun cellist" Sean Grissom, as well as Vyvienne Long who, in addition to her own projects, has played for those of Damien Rice. Cellists such as Natalie Haas, Abby Newton and Liz Davis Maxfield have contributed significantly to the use of cello playing in Celtic folk music, often with the cello featured as a primary melodic instrument and employing the skills and techniques of traditional fiddle playing. Lindsay Mac is becoming well known for playing the cello like a guitar, with her cover of The Beatles' "Blackbird".
+
+The cello is typically made from carved wood, although other materials such as carbon fiber or aluminum may be used. A traditional cello has a spruce top, with maple for the back, sides, and neck. Other woods, such as poplar or willow, are sometimes used for the back and sides. Less expensive cellos frequently have tops and backs made of laminated wood. Laminated cellos are widely used in elementary and secondary school orchestras and youth orchestras, because they are much more durable than carved wood cellos (i.e., they are less likely to crack if bumped or dropped) and they are much less expensive.
+
+The top and back are traditionally hand-carved, though less expensive cellos are often machine-produced. The sides, or ribs, are made by heating the wood and bending it around forms. The cello body has a wide top bout, narrow middle formed by two C-bouts, and wide bottom bout, with the bridge and F holes just below the middle. The top and back of the cello has decorative border inlay known as purfling. While purfling is attractive, it is also functional: if the instrument is struck, the purfling can prevent cracking of the wood. A crack may form at the rim of the instrument, but spreads no further. Without purfling, cracks can spread up or down the top or back. Playing, traveling and the weather all affect the cello and can increase a crack if purfling is not in place. Less expensive instruments typically have painted purfling.[citation needed]
+
+In the late 1920s and early 1930s, the Aluminum Company of America (Alcoa) as well as German luthier G.A. Pfretzschner produced an unknown number of aluminum cellos (in addition to aluminum double basses and violins).[12] Cello manufacturer Luis & Clark constructs cellos from carbon fibre. Carbon fibre instruments are particularly suitable for outdoor playing because of the strength of the material and its resistance to humidity and temperature fluctuations. Luis & Clark has produced over 1000 cellos, some of which are owned by cellists such as Yo-Yo Ma[13] and Josephine van Lier.[14]
+
+Above the main body is the carved neck. The neck has a curved cross-section on its underside, which is where the player's thumb runs along the neck during playing. The neck leads to a pegbox and the scroll, which are all normally carved out of a single piece of wood, usually maple. The fingerboard is glued to the neck and extends over the body of the instrument. The fingerboard is given a curved shape, matching the curve on the bridge. Both the fingerboard and bridge need to be curved so that the performer can bow individual strings. If the cello were to have a flat fingerboard and bridge, as with a typical guitar, the performer would only be able to bow the leftmost and rightmost two strings, or bow all the strings. The performer would not be able to play the inner two strings alone.
+
+The nut is a raised piece of wood, fitted where the fingerboard meets the pegbox, in which the strings rest in shallow slots or grooves to keep them the correct distance apart. The pegbox houses four tapered tuning pegs, one for each string. The pegs are used to tune the cello by either tightening or loosening the string. The pegs are called "friction pegs", because they maintain their position by friction. The scroll is a traditional ornamental part of the cello and a feature of all other members of the violin family. Ebony is usually used for the tuning pegs, fingerboard, and nut, but other hardwoods, such as boxwood or rosewood, can be used. Black fittings on low-cost instruments are often made from inexpensive wood that has been blackened or "ebonized" to look like ebony, which is much harder and more expensive. Ebonised parts such as tuning pegs may crack or split, and the black surface of the fingerboard will eventually wear down to reveal the lighter wood underneath.
+
+Historically, cello strings had cores made out of catgut, which, despite its name is made from dried out sheep or goat intestines. Most modern strings used in the 2010s are wound with metallic materials like aluminum, titanium and chromium. Cellists may mix different types of strings on their instruments. The pitches of the open strings are C, G, D, and A (black note heads in the playing range figure above), unless alternative tuning (scordatura) is specified by the composer. Some composers (e.g. Ottorino Respighi in the final movement of ‘’The Pines of Rome’’) ask that the low C be tuned down to a B-flat so that the performer can play a different low note on the lowest open string.
+
+The tailpiece and endpin are found in the lower part of the cello. The tailpiece is the part of the cello to which the "ball ends" of the strings are attached by passing them through holes. The tailpiece is attached to the bottom of the cello. The tailpiece is traditionally made of ebony or another hard wood, but can also be made of plastic or steel on lower-cost instruments. It attaches the strings to the lower end of the cello, and can have one or more fine tuners. The fine tuners are used to make smaller adjustments to the pitch of the string. The fine tuners can increase the tension of each string (raising the pitch) or decrease the tension of the string (lowering the pitch). When the performer is putting on a new string, the fine tuner for that string is normally reset to a middle position, and then the peg is turned to bring the string up to pitch. The fine turners are used for subtle, minor adjustments to pitch, such as tuning a cello to the oboe's 440 Hz A note or to tune the cello to a piano.
+
+The endpin or spike is made of wood, metal or rigid carbon fibre and supports the cello in playing position. The endpin can be retracted into the hollow body of the instrument when the cello is being transported in its case. This makes the cello easier to move about. When the performer wishes to play the cello, the endpin is pulled out to lengthen it. The endpin is locked into the player's preferred length with a screw mechanism. The adjustable nature of endpins enables performers of different ages and body sizes to adjust the endpin length to suit them.  In the Baroque period the cello was held between the calves, as there was no endpin at that time. The endpin was "introduced by Adrien Servais c. 1845 to give the instrument greater stability".[15] Modern endpins are retractable and adjustable; older ones were removed when not in use. (The word "endpin" sometimes also refers to the button of wood located at this place in all instruments in the violin family, but this is usually called "tailpin".[16]) The sharp tip of the cello's endpin is sometimes capped with a rubber tip that protects the tip from dulling and prevents the cello from slipping on the floor. Many cellists use a rubber pad with a metal cup to keep the tip from slipping on the floor. A number of accessories to keep the endpin from slipping; these include ropes which attach to the chair leg and other devices.
+
+The bridge holds the strings above the cello and transfers their vibrations to the top of the instrument and the soundpost inside (see below). The bridge is not glued, but rather held in place by the tension of the strings. The bridge is usually positioned by the cross point of the "f-hole" (i.e., where the horizontal line occurs in the "f"). The f-holes, named for their shape, are located on either side of the bridge, and allow air to move in and out of the instrument as part of the sound-production process.  They probably actually stand for an old style medial S, for words related to Sound.[citation needed] The f-holes also act as access points to the interior of the cello for repairs or maintenance. Sometimes a small length of rubber hose containing a water-soaked sponge, called a Dampit, is inserted through the f-holes, and serves as a humidifier. This keeps the wood components of the cello from drying out.
+
+Internally, the cello has two important features: a bass bar, which is glued to the underside of the top of the instrument, and a round wooden sound post, a solid wooden cylinder which is wedged between the top and bottom plates. The bass bar, found under the bass foot of the bridge, serves to support the cello's top and distribute the vibrations from the strings to the body of the instrument. The sound post, found under the treble side of the bridge, connects the back and front of the cello. Like the bridge, the sound post is not glued, but is kept in place by the tensions of the bridge and strings. Together, the bass bar and sound post transfer the strings' vibrations to the top (front) of the instrument (and to a lesser extent the back), acting as a diaphragm to produce the instrument's sound.
+
+Cellos are constructed and repaired using hide glue, which is strong but reversible, allowing for disassembly when needed. Tops may be glued on with diluted glue, since some repairs call for the removal of the top. Theoretically, hide glue is weaker than the body's wood, so as the top or back shrinks side-to-side, the glue holding it lets go and the plate does not crack. Cellists repairing cracks in their cello do not use regular wood glue, because it cannot be steamed open when a repair has to be made by a luthier.
+
+Traditionally, bows are made from pernambuco or brazilwood. Both come from the same species of tree (Caesalpinia echinata), but pernambuco, used for higher-quality bows, is the heartwood of the tree and is darker in color than brazilwood (which is sometimes stained to compensate). Pernambuco is a heavy, resinous wood with great elasticity, which makes it an ideal wood for instrument bows. Horsehair is stretched out between the two ends of the bow. The taut horsehair is drawn over the strings to produce the cello's characteristic tone. A small knob is twisted to increase or decrease the tension of the horsehair. The tension on the bow is released when the instrument is not being used. The amount of tension a cellist puts on the bow hair depends on the preferences of the player, the style of music being played, and for students, the preferences of their teacher.
+
+Bows are also made from other materials, such as carbon fibre—stronger than wood—and fiberglass (often used to make inexpensive, lower-quality student bows). An average cello bow is 73 cm (29 in) long (shorter than a violin or viola bow) 3 cm (1.2 in) high (from the frog to the stick) and 1.5 cm (0.59 in) wide. The frog of a cello bow typically has a rounded corner like that of a viola bow, but is wider. A cello bow is roughly 10 g (0.35 oz) heavier than a viola bow, which in turn is roughly 10 g (0.35 oz) heavier than a violin bow.
+
+Bow hair is traditionally horsehair, though synthetic hair, in varying colors, is also used. Prior to playing, the musician tightens the bow by turning a screw to pull the frog (the part of the bow under the hand) back, and increase the tension of the hair. Rosin is applied by the player to make the hair sticky. Bows need to be re-haired periodically. Baroque style (1600–1750) cello bows were much thicker and were formed with a larger outward arch when compared to modern cello bows. The inward arch of a modern cello bow produces greater tension, which in turn gives off a louder sound.
+
+The cello bow has also been used to play electric guitars. Jimmy Page pioneered its application on tracks such as "Dazed and Confused". The post-rock Icelandic band Sigur Rós's lead singer often plays a guitar using a cello bow.
+
+In 1989, the German cellist Michael Bach began developing a curved bow, encouraged by John Cage, Dieter Schnebel, Mstislav Rostropovich and Luigi Colani: and since then many pieces have been composed especially for it. This curved bow (BACH.Bow) is a convex curved bow which, unlike the ordinary bow, renders possible polyphonic playing on the various strings of the instrument. The solo repertoire for violin and cello by J. S. Bach the BACH.Bow is particularly suited to it: and it was developed with this in mind, polyphonic playing being required, as well as monophonic.
+
+When a string is bowed or plucked, it vibrates and moves the air around it, producing sound waves. Because the string is quite thin, not much air is moved by the string itself, and consequently if the string was not mounted on a hollow body, the sound would be weak. In acoustic stringed instruments such as the cello, this lack of volume is solved by mounting the vibrating string on a larger hollow wooden body. The vibrations are transmitted to the larger body, which can move more air and produce a louder sound. Different designs of the instrument produces variations in the instrument’s vibrational patterns and thus changes the character of the sound produced.[18] A string’s fundamental pitch can be adjusted by changing its stiffness, which depends on tension and length. Tightening a string stiffens it by increasing both the outward forces along its length and the net forces it experiences during a distortion.[19] A cello can be tuned by adjusting the tension of its strings, by turning the tuning pegs mounted on its pegbox, and tension adjusters (fine tuners) on the tail piece.
+
+A string's length also affects its fundamental pitch. Shortening a string stiffens it by increasing its curvature during a distortion and subjecting it to larger net forces. Shortening the string also reduces its mass,  but does not alter the mass per unit length, and it is the latter ratio rather than the total mass which governs the frequency. The string vibrates in a standing wave whose speed of propagation is given by √T/m,  where T is the tension and m is the mass per unit length; there is a node at either end of the vibrating length, and thus the vibrating length l is half a wavelength.    Since the frequency of any wave is equal to the speed divided by the wavelength,  we have frequency = 1/2l × √T/m. (Note that some writers, including Muncaster (cited below) use the Greek letter μ in place of m.) Thus shortening a string increases the frequency, and thus the pitch. Because of this effect, you can raise and change the pitch of a string by pressing it against the fingerboard in the cello’s neck and effectively shortening it.[20] Likewise strings with less mass per unit length, if under the same tension, will have a higher frequency and thus higher pitch than more massive strings. This is a prime reason why the different strings on all string instruments have different fundamental pitches, with the lightest strings having the highest pitches.
+
+A played note of E or F-sharp has a frequency which is often very close to the natural resonating frequency of the body of the instrument,  and if the problem is not addressed this can set the body into near resonance.   This may cause an unpleasant sudden amplification of this pitch,  and additionally a loud beating sound results from the interference produced between these nearby frequencies; this is known as the “wolf tone” because it is an unpleasant growling sound. The wood resonance appears to be split into two frequencies by the driving force of the sounding string. These two periodic resonances beat with each other. This wolf tone must be eliminated or significantly reduced for the cello to play the nearby notes with a pleasant tone. This can be accomplished by modifying the cello front plate, attaching a wolf eliminator (a metal cylinder or a rubber cylinder encased in metal), or moving the sound post.[21]
+
+When a string is bowed or plucked to produce a note, the fundamental note is accompanied by higher frequency overtones. Each sound has a particular recipe of frequencies that combine to make the total sound.[22]
+
+Playing the cello is done while seated with the instrument supported on the floor by the endpin. The left hand fingertips stop the strings on the fingerboard, determining the pitch of the fingered note. The right hand plucks or bows the strings to sound the notes. The left hand fingertips stop the strings along their length, determining the pitch of each fingered note. Stopping the string closer to the bridge results in higher-pitched sound, because the vibrating string length has been shortened. In the neck positions (which use just less than half of the fingerboard, nearest the top of the instrument), the thumb rests on the back of the neck; in thumb position (a general name for notes on the remainder of the fingerboard) the thumb usually rests alongside the fingers on the string and the side of the thumb is used to play notes. The fingers are normally held curved with each knuckle bent, with the fingertips in contact with the string. If a finger is required on two (or more) strings at once to play perfect fifths (in double stops or chords) it is used flat. In slower, or more expressive playing, the contact point can move slightly away from the nail to the pad of the finger, allowing a fuller vibrato.
+
+Vibrato is a small oscillation in the pitch of a note, usually considered an expressive technique. Harmonics played on the cello fall into two classes; natural and artificial. Natural harmonics are produced by lightly touching (but not depressing) the string with the finger at certain places, and then bowing (or, rarely, plucking) the string. For example, the halfway point of the string will produce a harmonic that is one octave above the unfingered (open) string. Natural harmonics only produce notes that are part of the harmonic series on a particular string. Artificial harmonics (also called false harmonics or stopped harmonics), in which the player depresses the string fully with one finger while touching the same string lightly with another finger, can produce any note above middle C. 
+Glissando (Italian for "sliding") is an effect played by sliding the finger up or down the fingerboard without releasing the string. This causes the pitch to rise and fall smoothly, without separate, discernible steps.
+
+In cello playing, the bow is much like the breath of a wind instrument player. Arguably, it is the major factor in the expressiveness of the playing. The right hand holds the bow and controls the duration and character of the notes. The bow is drawn across the strings roughly halfway between the end of the fingerboard and the bridge, in a direction perpendicular to the strings. The bow is held and manipulated with all five fingers of the right hand, the thumb opposite the fingers and closer to the cellist's body. Tone production and volume of sound depend on a combination of several factors. The three most important ones are: bow speed, weight applied to the string, and point of contact of the bow hair with the string.
+
+Double stops involve the playing of two notes at the same time. Two strings are fingered simultaneously, and the bow is drawn so as to sound them both at once. In pizzicato playing, the string is plucked directly with the fingers or thumb. Pizzicato is often abbreviated as "pizz.". Position of the hand is slightly over the finger board and away from the bridge.
+
+A player using the col legno technique strikes or rubs the strings with the wood of the bow rather than the hair. In spiccato playing, the strings are not "drawn" by the bow hair but struck by it, while still retaining some horizontal motion, to generate a more percussive, crisp sound. In staccato, the player moves the bow a small distance and stops it on the string, making a short sound, the rest of the written duration being taken up by silence. 
+Legato is a technique where the notes are smoothly connected without accents or breaks. It is noted by a slur (curved line) above or below – depending on their position on the staff – the notes of the passage that is to be played legato.
+
+Sul ponticello ("on the bridge") refers to bowing closer to the bridge, while sul tasto ("on the fingerboard") calls for bowing nearer the end of the fingerboard. Sul tasto produces a more flute-like sound, with more emphasis on the fundamental frequency of the note, and softened overtones.
+
+Standard-sized cellos are referred to as "full-size" or "​4⁄4" but are also made in smaller (fractional) sizes, including ​7⁄8, ​3⁄4, ​1⁄2, ​1⁄4, ​1⁄8, ​1⁄10, and ​1⁄16. The fractions refer to volume rather than length, so a 1/2 size cello is much longer than half the length of a full size.  The smaller cellos are identical to standard cellos in construction, range, and usage, but are simply scaled-down for the benefit of children and shorter adults.
+
+Cellos in sizes larger than ​4⁄4 do exist, and cellists with unusually large hands may require such a non-standard instrument. Cellos made before approximately 1700 tended to be considerably larger than those made and commonly played today. Around 1680, changes in string-making technology made it possible to play lower-pitched notes on shorter strings. The cellos of Stradivari, for example, can be clearly divided into two models: the style made before 1702, characterized by larger instruments (of which only three exist in their original size and configuration), and the style made during and after 1707, when Stradivari began making smaller cellos. This later model is the design most commonly used by modern luthiers. The scale length of a ​4⁄4 cello is about 70 cm (27 1⁄2 in). The new size offered fuller tonal projection and greater range of expression. The instrument in this form was able to contribute to more pieces musically and offered the possibility of greater physical dexterity for the player to develop technique.[23]
+
+There are many accessories for the cello.
+
+Cellos are made by luthiers, specialists in building and repairing stringed instruments, ranging from guitars to violins. The following luthiers are notable for the cellos they have produced:
+
+A person who plays the cello is called a cellist. For a list of notable cellists, see the list of cellists and Category:Cellists.
+
+Specific instruments are famous (or become famous) for a variety of reasons. An instrument's notability may arise from its age, the fame of its maker, its physical appearance, its acoustic properties, and its use by notable performers. The most famous instruments are generally known for all of these things. The most highly prized instruments are now collector's items, and are priced beyond the reach of most musicians. These instruments are typically owned by some kind of organization or investment group, which may loan the instrument to a notable performer. (For example, the Davidov Stradivarius, which is currently in the possession of one of the most widely known living cellists, Yo-Yo Ma, is actually owned by the Vuitton Foundation.[25])
+
+Some notable cellos:
+
+La Mariée, a 1950 painting by Marc Chagall which is prominently featured in the 1999 film Notting Hill, portrays a goat playing a cello.

en/6002.html.txt

@@ -0,0 +1,185 @@
+
+
+The violin, sometimes known as a fiddle, is a wooden string instrument in the violin family. Most violins have a hollow wooden body. It is the smallest and highest-pitched instrument (soprano) in the family in regular use.[a] The violin typically has four strings, usually tuned in perfect fifths with notes G3, D4, A4, E5, and is most commonly played by drawing a bow across its strings. It can also be played by plucking the strings with the fingers (pizzicato) and, in specialized cases, by striking the strings with the wooden side of the bow (col legno).
+
+Violins are important instruments in a wide variety of musical genres. They are most prominent in the Western classical tradition, both in ensembles (from chamber music to orchestras) and as solo instruments. Violins are also important in many varieties of folk music, including country music, bluegrass music and in jazz. Electric violins with solid bodies and piezoelectric pickups are used in some forms of rock music and jazz fusion, with the pickups plugged into instrument amplifiers and speakers to produce sound. The violin has come to be incorporated in many non-Western music cultures, including Indian music and Iranian music. The name fiddle is often used regardless of the type of music played on it.
+
+The violin was first known in 16th-century Italy, with some further modifications occurring in the 18th and 19th centuries to give the instrument a more powerful sound and projection. In Europe, it served as the basis for the development of other stringed instruments used in Western classical music, such as the viola.[1][2][3]
+
+Violinists and collectors particularly prize the fine historical instruments made by the Stradivari, Guarneri, Guadagnini and Amati families from the 16th to the 18th century in Brescia and Cremona (Italy) and by Jacob Stainer in Austria. According to their reputation, the quality of their sound has defied attempts to explain or equal it, though this belief is disputed.[4][5] Great numbers of instruments have come from the hands of less famous makers, as well as still greater numbers of mass-produced commercial "trade violins" coming from cottage industries in places such as Saxony, Bohemia, and Mirecourt. Many of these trade instruments were formerly sold by Sears, Roebuck and Co. and other mass merchandisers.
+
+The components of a violin are usually made from different types of wood. Violins can be strung with gut, Perlon or other synthetic, or steel strings. A person who makes or repairs violins is called a luthier or violinmaker. One who makes or repairs bows is called an archetier or bowmaker.
+
+The word "violin" was first used in English in the 1570s.[6] The word "violin" comes from "Italian violino, [a] diminutive of viola". The term "viola" comes from the expression for "tenor violin" in 1797, from Italian viola, from Old Provençal viola, [which came from] Medieval Latin vitula" as a term which means "stringed instrument," perhaps [coming] from Vitula, Roman goddess of joy..., or from related Latin verb vitulari, "to exult, be joyful."[7] The related term "Viola da gamba" means "bass viol" (1724) is from Italian, literally "a viola for the leg" (i.e. to hold between the legs)."[7]  A violin is the "modern form of the smaller, medieval viola da braccio." ("arm viola")[6]
+
+The violin is often called a fiddle, either when used in a folk music context, or even in Classical music scenes, as an informal nickname for the instrument.[8] The word "fiddle" was first used in English in the late 14th century.[8] The word "fiddle" comes from "fedele, fydyll, fidel, earlier fithele, from Old English fiðele "fiddle," which is related to Old Norse fiðla, Middle Dutch vedele, Dutch vedel, Old High German fidula, German Fiedel, "a fiddle;" all of uncertain origin." As to the origin of the word "fiddle", the "...usual suggestion, based on resemblance in sound and sense, is that it is from Medieval Latin vitula."[8]
+
+The earliest stringed instruments were mostly plucked (for example, the Greek lyre). Two-stringed, bowed instruments, played upright and strung and bowed with horsehair, may have originated in the nomadic equestrian cultures of Central Asia, in forms closely resembling the modern-day Mongolian Morin huur and the Kazakh Kobyz. Similar and variant types were probably disseminated along east–west trading routes from Asia into the Middle East,[9][10] and the Byzantine Empire.[11][12]
+
+The direct ancestor of all European bowed instruments is the Arabic rebab (ربابة), which developed into the Byzantine lyra by the 9th century and later the European rebec.[13][14][15] The first makers of violins probably borrowed from various developments of the Byzantine lyra. These included the vielle (also known as the fidel or viuola) and the lira da braccio.[11][16]
+The violin in its present form emerged in early 16th-century northern Italy. The earliest pictures of violins, albeit with three strings, are seen in northern Italy around 1530, at around the same time as the words "violino" and "vyollon" are seen in Italian and French documents. One of the earliest explicit descriptions of the instrument, including its tuning, is from the Epitome musical by Jambe de Fer, published in Lyon in 1556.[17] By this time, the violin had already begun to spread throughout Europe.
+
+The violin proved very popular, both among street musicians and the nobility; the French king Charles IX ordered Andrea Amati to construct 24 violins for him in 1560.[18] One of these "noble" instruments, the Charles IX, is the oldest surviving violin. The finest Renaissance carved and decorated violin in the world is the Gasparo da Salò (c.1574) owned by Ferdinand II, Archduke of Austria and later, from 1841, by the Norwegian virtuoso Ole Bull, who used it for forty years and thousands of concerts, for its very powerful and beautiful tone, similar to that of a Guarneri.[19] "The Messiah" or "Le Messie" (also known as the "Salabue") made by Antonio Stradivari in 1716 remains pristine. It is now located in the Ashmolean Museum of Oxford.[20]
+
+The most famous violin makers (luthiers) between the 16th century and the 18th century include:
+
+Significant changes occurred in the construction of the violin in the 18th century, particularly in the length and angle of the neck, as well as a heavier bass bar. The majority of old instruments have undergone these modifications, and hence are in a significantly different state than when they left the hands of their makers, doubtless with differences in sound and response.[23] But these instruments in their present condition set the standard for perfection in violin craftsmanship and sound, and violin makers all over the world try to come as close to this ideal as possible.
+
+To this day, instruments from the so-called Golden Age of violin making, especially those made by Stradivari, Guarneri del Gesù and Montagnana are the most sought-after instruments by both collectors and performers.  The current record amount paid for a Stradivari violin is £9.8 million (US$15.9 million at that time), when the instrument known as the Lady Blunt was sold by Tarisio Auctions in an online auction on June 20, 2011.[24]
+
+A violin generally consists of a spruce top (the soundboard, also known as the top plate, table, or belly), maple ribs and back, two endblocks, a neck, a bridge, a soundpost, four strings, and various fittings, optionally including a chinrest, which may attach directly over, or to the left of, the tailpiece. A distinctive feature of a violin body is its hourglass-like shape and the arching of its top and back. The hourglass shape comprises two upper bouts, two lower bouts, and two concave C-bouts at the waist, providing clearance for the bow. The "voice" or sound of a violin depends on its shape, the wood it is made from, the graduation (the thickness profile) of both the top and back, the varnish that coats its outside surface and the skill of the luthier in doing all of these steps. The varnish and especially the wood continue to improve with age, making the fixed supply of old well-made violins built by famous luthiers much sought-after.
+
+The majority of glued joints in the instrument use animal hide glue rather than common white glue for a number of reasons. Hide glue is capable of making a thinner joint than most other glues, it is reversible (brittle enough to crack with carefully applied force, and removable with very warm water) when disassembly is needed, and since fresh hide glue sticks to old hide glue, more original wood can be preserved when repairing a joint. (More modern glues must be cleaned off entirely for the new joint to be sound, which generally involves scraping off some wood along with the old glue.) Weaker, diluted glue is usually used to fasten the top to the ribs, and the nut to the fingerboard, since common repairs involve removing these parts. The purfling running around the edge of the spruce top provides some protection against cracks originating at the edge. It also allows the top to flex more independently of the rib structure. Painted-on faux purfling on the top is usually a sign of an inferior instrument. The back and ribs are typically made of maple, most often with a matching striped figure, referred to as flame, fiddleback, or tiger stripe.
+
+The neck is usually maple with a flamed figure compatible with that of the ribs and back. It carries the fingerboard, typically made of ebony, but often some other wood stained or painted black on cheaper instruments. Ebony is the preferred material because of its hardness, beauty, and superior resistance to wear. Fingerboards are dressed to a particular transverse curve, and have a small lengthwise "scoop," or concavity, slightly more pronounced on the lower strings, especially when meant for gut or synthetic strings. Some old violins (and some made to appear old) have a grafted scroll, evidenced by a glue joint between the pegbox and neck. Many authentic old instruments have had their necks reset to a slightly increased angle, and lengthened by about a centimeter. The neck graft allows the original scroll to be kept with a Baroque violin when bringing its neck into conformance with modern standards.
+
+The bridge is a precisely cut piece of maple that forms the lower anchor point of the vibrating length of the strings and transmits the vibration of the strings to the body of the instrument. Its top curve holds the strings at the proper height from the fingerboard in an arc, allowing each to be sounded separately by the bow. The sound post, or soul post, fits precisely inside the instrument between the back and top, at a carefully chosen spot near the treble foot of the bridge, which it helps support. It also influences the modes of vibration of the top and the back of the instrument.
+
+The tailpiece anchors the strings to the lower bout of the violin by means of the tailgut, which loops around an ebony button called the tailpin (sometimes confusingly called the endpin, like the cello's spike), which fits into a tapered hole in the bottom block. Very often the E string will have a fine tuning lever worked by a small screw turned by the fingers. Fine tuners may also be applied to the other strings, especially on a student instrument, and are sometimes built into the tailpiece. The fine tuners enable the performer to make small changes in the pitch of a string. At the scroll end, the strings wind around the wooden tuning pegs in the pegbox. The tuning pegs are tapered and fit into holes in the peg box. The tuning pegs are held in place by the friction of wood on wood. Strings may be made of metal or less commonly gut or gut wrapped in metal. Strings usually have a colored silk wrapping at both ends, for identification of the string (e.g., G string, D string, A string or E string) and to provide friction against the pegs. The tapered pegs allow friction to be increased or decreased by the player applying appropriate pressure along the axis of the peg while turning it.
+
+Strings were first made of sheep gut (commonly known as catgut, which despite the name, did not come from cats), or simply gut, which was stretched, dried, and twisted. In the early years of the 20th century, strings were made of either gut or steel. Modern strings may be gut, solid steel, stranded steel, or various synthetic materials such as perlon, wound with various metals, and sometimes plated with silver. Most E strings are unwound, either plain or plated steel. Gut strings are not as common as they once were, but many performers use them to achieve a specific sound especially in historically informed performance of Baroque music. Strings have a limited lifetime. Eventually, when oil, dirt, corrosion, and rosin accumulate, the mass of the string can become uneven along its length. Apart from obvious things, such as the winding of a string coming undone from wear, players generally change a string when it no longer plays "true" (with good intonation on the harmonics), losing the desired tone, brilliance and intonation. String longevity depends on string quality and playing intensity.
+
+A violin is tuned in fifths, in the notes G3, D4, A4, E5. The lowest note of a violin, tuned normally, is G3, or G below middle C (C4). (On rare occasions, the lowest string may be tuned down by as much as a fourth, to D3.) The highest note is less well defined: E7, the E two octaves above the open string (which is tuned to E5) may be considered a practical limit for orchestral violin parts,[25] but it is often possible to play higher, depending on the length of the fingerboard and the skill of the violinist. Yet higher notes (up to C8) can be sounded by stopping the string, reaching the limit of the fingerboard, and/or by using artificial harmonics.
+
+The arched shape, the thickness of the wood, and its physical qualities govern the sound of a violin. Patterns of the node made by sand or glitter sprinkled on the plates with the plate vibrated at certain frequencies, called Chladni patterns, are occasionally used by luthiers to verify their work before assembling the instrument.[26]
+
+Apart from the standard, full (​4⁄4) size, violins are also made in so-called fractional sizes of ​7⁄8, ​3⁄4, ​1⁄2, ​1⁄4, ​1⁄8, ​1⁄10, ​1⁄16, ​1⁄32 and even ​1⁄64. These smaller instruments are commonly used by young players, whose fingers are not long enough to reach the correct positions on full-sized instruments.
+
+While related in some sense to the dimensions of the instruments, the fractional sizes are not intended to be literal descriptions of relative proportions. For example, a ​3⁄4-sized instrument is not three-quarters the length of a full size instrument. The body length (not including the neck) of a full-size, or ​4⁄4, violin is 356 mm (14.0 in), smaller in some 17th-century models. A ​3⁄4 violin's body length is 335 mm (13.2 in), and a ​1⁄2 size is 310 mm (12.2 in). With the violin's closest family member, the viola, size is specified as body length in inches or centimeters rather than fractional sizes. A full-size viola averages 40 cm (16 in). However, each individual adult will determine which size of viola to use.
+
+Occasionally, an adult with a small frame may use a so-called ​7⁄8 size violin instead of a full-size instrument.  Sometimes called a lady's violin, these instruments are slightly shorter than a full size violin, but tend to be high-quality instruments capable of producing a sound that is comparable to that of fine full size violins. 5 string violin sizes may differ from the normal 4 string.
+
+The instrument which corresponds to the violin in the violin octet is the mezzo violin, tuned the same as a violin but with a slightly longer body. The strings of the mezzo violin are the same length as those of the standard violin. This instrument is not in common use.[27]
+
+Violins are tuned by turning the pegs in the pegbox under the scroll, or by adjusting the fine tuner screws at the tailpiece. All violins have pegs; fine tuners (also called fine adjusters) are optional. Most fine tuners consist of a metal screw that moves a lever attached to the string end. They permit very small pitch adjustments much more easily than the pegs. By turning one clockwise, the pitch becomes sharper (as the string is under more tension) and turning one counterclockwise, the pitch becomes flatter (as the string is under less tension). Fine tuners on all four of the strings are very helpful when using those that have a steel core, and some players use them with synthetic strings as well. Since modern E strings are steel, a fine tuner is nearly always fitted for that string. Fine tuners are not used with gut strings, which are more elastic than steel or synthetic-core strings and do not respond adequately to the very small movements of fine tuners.
+
+To tune a violin, the A string is first tuned to a standard pitch (usually A=440 Hz). (When accompanying or playing with a fixed-pitch instrument such as a piano or accordion, the violin tunes to it. The oboe is generally the instrument used to tune orchestras where violins are present, since its sound is penetrating and can be heard over the other woodwinds) The other strings are then tuned against each other in intervals of perfect fifths by bowing them in pairs. A minutely higher tuning is sometimes employed for solo playing to give the instrument a brighter sound; conversely, Baroque music is sometimes played using lower tunings to make the violin's sound more gentle. After tuning, the instrument's bridge may be examined to ensure that it is standing straight and centered between the inner nicks of the f-holes; a crooked bridge may significantly affect the sound of an otherwise well-made violin. After extensive playing, the holes into which the tuning pegs are inserted can become worn, which can lead the peg to slip under tension. This can lead to the pitch of the string dropping, or if the peg becomes completely loose, to the string completely losing tension. A violin in which the tuning pegs are slipping needs to be repaired by a luthier or violin repairperson. Peg dope or peg compound, used regularly, can delay the onset of such wear, while allowing the pegs to turn smoothly.
+
+The tuning G–D–A–E is used for most violin music, both in Classical music, jazz and folk music. Other tunings are occasionally employed; the G string, for example, can be tuned up to A. The use of nonstandard tunings in classical music is known as scordatura; in some folk styles, it is called cross tuning. One famous example of scordatura in classical music is Camille Saint-Saëns' Danse Macabre, where the solo violin's E string is tuned down to E♭ to impart an eerie dissonance to the composition. Other examples are the third movement of Contrasts, by Béla Bartók, where the E string is tuned down to E♭ and the G tuned to a G♯, and the Mystery Sonatas by Biber, in which each movement has different scordatura tuning.
+
+In Indian classical music and Indian light music, the violin is likely to be tuned to D♯–A♯–D♯–A♯ in the South Indian style. As there is no concept of absolute pitch in Indian classical music, any convenient tuning maintaining these relative pitch intervals between the strings can be used. Another prevalent tuning with these intervals is B♭–F–B♭–F, which corresponds to Sa–Pa–Sa–Pa in the Indian carnatic classical music style. In the North Indian Hindustani style, the tuning is usually Pa-Sa-Pa-Sa instead of Sa–Pa–Sa–Pa. This could correspond to F–B♭–F–B♭, for instance. In Iranian classical music and Iranian light music, the violin ls different tunings in any Dastgah, the violin is likely to be tuned (E–A–E–A) in Dastgah-h Esfahan or in  Dastgāh-e Šur is (E–A–D–E) and (E–A–E–E), in Dastgāh-e Māhur is (E–A–D–A). In Arabic classical music, the A and E strings are lowered by a whole step i.e. G–D–G–D. This is to ease playing Arabic maqams, especially those containing quarter tones.
+
+While most violins have four strings, there are violins with additional strings. Some have as many as seven strings. Seven strings is generally thought to be the maximum number of strings that can be put on a bowed string instrument, because with more than seven strings, it would be impossible to play a particular inner string individually with the bow. Instruments with seven strings are very rare. The extra strings on such violins typically are lower in pitch than the G-string; these strings are usually tuned to C, F, and B♭. If the instrument's playing length, or string length from nut to bridge, is equal to that of an ordinary full-scale violin; i.e., a bit less than 13 inches (33 cm), then it may be properly termed a violin. Some such instruments are somewhat longer and should be regarded as violas. Violins with five strings or more are typically used in jazz or folk music. Some custom-made instruments have extra strings which are not bowed, but which sound sympathetically, due to the vibrations of the bowed strings.
+
+A violin is usually played using a bow consisting of a stick with a ribbon of horsehair strung between the tip and frog (or nut, or heel) at opposite ends. A typical violin bow may be 75 cm (30 in) overall, and weigh about 60 g (2.1 oz). Viola bows may be about 5 mm (0.20 in) shorter and 10 g (0.35 oz) heavier. At the frog end, a screw adjuster tightens or loosens the hair. Just forward of the frog, a leather thumb cushion, called the grip, and winding protect the stick and provide a strong grip for the player's hand. Traditional windings are of wire (often silver or plated silver), silk, or baleen ("whalebone", now substituted by alternating strips of tan and black plastic.) Some fiberglass student bows employ a plastic sleeve as grip and winding.
+
+Bow hair traditionally comes from the tail of a grey male horse (which has predominantly white hair). Some cheaper bows use synthetic fiber. Solid rosin is rubbed onto the hair, to render it slightly sticky; when the bow is drawn across a string, the friction between them makes the string vibrate. Traditional materials for the more costly bow sticks include snakewood, and brazilwood (which is also known as Pernambuco wood). Some recent bow design innovations use carbon fiber (CodaBows) for the stick, at all levels of craftsmanship. Inexpensive bows for students are made of less costly timbers, or from fiberglass (Glasser).
+
+The violin is played either seated or standing up. Solo players (whether playing alone, with a piano or with an orchestra) play mostly standing up (unless prevented by a physical disability such as in the case of Itzhak Perlman), while in the orchestra and in chamber music it is usually played seated. In the 2000s and 2010s, some orchestras performing Baroque music (such as the Freiburg Baroque Orchestra) have had all of their violins and violas, solo and ensemble, perform standing up.
+
+The standard way of holding the violin is with the left side of the jaw resting on the chinrest of the violin, and supported by the left shoulder, often assisted by a shoulder rest (or a sponge and an elastic band for younger players who struggle with shoulder rests). The jaw and the shoulder must hold the violin firmly enough to allow it to remain stable when the left hand goes from a high position (a high pitched note far up on the fingerboard) to a low one (nearer to the pegbox). In the Indian posture, the stability of the violin is guaranteed by its scroll resting on the side of the foot.
+
+While teachers point out the vital importance of good posture both for the sake of the quality of the playing and to reduce the chance of repetitive strain injury, advice as to what good posture is and how to achieve it differs in details. However, all insist on the importance of a natural relaxed position without tension or rigidity. Things which are almost universally recommended is keeping the left wrist straight (or very nearly so) to allow the fingers of the left hand to move freely and to reduce the chance of injury and keeping either shoulder in a natural relaxed position and avoiding raising either of them in an exaggerated manner. This, like any other unwarranted tension, would limit freedom of motion, and increase the risk of injury.
+
+Hunching can hamper good playing because it throws the body off balance and makes the shoulders rise. Another sign that comes from unhealthy tension is pain in the left hand, which indicates too much pressure when holding the violin.
+
+The left hand determines the sounding length of the string, and thus the pitch of the string, by "stopping" it (pressing it) against the fingerboard with the fingertips, producing different pitches. As the violin has no frets to stop the strings, as is usual with the guitar, the player must know exactly where to place the fingers on the strings to play with good intonation (tuning). Beginning violinists play open strings and the lowest position, nearest to the nut. Students often start with relatively easy keys, such as A Major and G major. Students are taught scales and simple melodies. Through practice of scales and arpeggios and ear training, the violinist's left hand eventually "finds" the notes intuitively by muscle memory.
+
+Beginners sometimes rely on tapes placed on the fingerboard for proper left hand finger placement, but usually abandon the tapes quickly as they advance. Another commonly used marking technique uses dots of white-out on the fingerboard, which wear off in a few weeks of regular practice. This practice, unfortunately, is used sometimes in lieu of adequate ear-training, guiding the placement of fingers by eye and not by ear. Especially in the early stages of learning to play, the so-called "ringing tones" are useful. There are nine such notes in first position, where a stopped note sounds a unison or octave with another (open) string, causing it to resonate sympathetically. Students often use these ringing tones to check the intonation of the stopped note by seeing if it is harmonious with the open string. For example, when playing the stopped pitch "A" on the G string, the violinist could play the open D string at the same time, to check the intonation of the stopped "A". If the "A" is in tune, the "A" and the open D string should produce a harmonious perfect fourth.
+
+Violins are tuned in perfect fifths, like all the orchestral strings (violin, viola, cello) except the double bass, which is tuned in perfect fourths. Each subsequent note is stopped at a pitch the player perceives as the most harmonious, "when unaccompanied, [a violinist] does not play consistently in either the tempered or the natural [just] scale, but tends on the whole to conform with the Pythagorean scale."[28] When violinists are playing in a string quartet or a string orchestra, the strings typically "sweeten" their tuning to suit the key they are playing in. When playing with an instrument tuned to equal temperament, such as a piano, skilled violinists adjust their tuning to match the equal temperament of the piano to avoid discordant notes.
+
+The fingers are conventionally numbered 1 (index) through 4 (little finger) in music notation, such as sheet music and etude books.  Especially in instructional editions of violin music, numbers over the notes may indicate which finger to use, with 0 or O indicating an open string. The chart to the right shows the arrangement of notes reachable in first position. Not shown on this chart is the way the spacing between note positions becomes closer as the fingers move up (in pitch) from the nut.  The bars at the sides of the chart represent the usual possibilities for beginners' tape placements, at 1st, high 2nd, 3rd, and 4th fingers.
+
+The placement of the left hand on the fingerboard is characterized by "positions".  First position, where most beginners start (although some methods start in third position), is the most commonly used position in string music. Music composed for beginning youth orchestras is often mostly in first position. The lowest note available in this position in standard tuning is an open G; the highest note in first position is played with the fourth finger on the E-string, sounding a B. Moving the hand up the neck, so the first finger takes the place of the second finger, brings the player into second position. Letting the first finger take the first-position place of the third finger brings the player to third position, and so on. A change of positions, with its associated movement of the hand, is referred to as a shift, and effective shifting maintaining accurate intonation and a smooth legato (connected) sound is a key element of technique at all levels. Often a "guide finger" is used; the last finger to play a note in the old position continuously lightly touches the string during the course of the shift to end up on its correct place in the new position. In elementary shifting exercises the "guide finger" is often voiced while it glides up and down the string, so the player can establish by ear whether they are landing in the correct place, however outside of these exercises it should rarely be audible (unless the performer is consciously applying a portamento effect for expressive reasons).
+
+In the course of a shift in low positions, the thumb of the left hand moves up or down the neck of the instrument so as to remain in the same position relative to the fingers (though the movement of the thumb may occur slightly before, or slightly after, the movement of the fingers). In such positions, the thumb is often thought of as an 'anchor' whose location defines what position the player is in. In very high positions, the thumb is unable to move with the fingers as the body of the instrument gets in the way. Instead, the thumb works around the neck of the instrument to sit at the point at which the neck meets the right bout of the body, and remains there while the fingers move between the high positions.
+
+A note played outside of the normal compass of a position, without any shift, is referred to as an extension. For instance, in third position on the A string, the hand naturally sits with the first finger on D♮ and the fourth on either G♮ or G♯. Stretching the first finger back down to a C♯, or the fourth finger up to an A♮, forms an extension. Extensions are commonly used where one or two notes are slightly out of an otherwise solid position, and give the benefit of being less intrusive than a shift or string crossing. The lowest position on the violin is referred to as "half position". In this position the first finger is on a "low first position" note, e.g. B♭ on the A string, and the fourth finger is in a downward extension from its regular position, e.g. D♮ on the A string, with the other two fingers placed in between as required. As the position of the thumb is typically the same in "half position" as in first position, it is better thought of as a backwards extension of the whole hand than as a genuine position.
+
+The upper limit of the violin's range is largely determined by the skill of the player, who may easily play more than two octaves on a single string, and four octaves on the instrument as a whole. Position names are mostly used for the lower positions and in method books and etudes; for this reason, it is uncommon to hear references to anything higher than seventh position. The highest position, practically speaking, is 13th position. Very high positions are a particular technical challenge, for two reasons. Firstly, the difference in location of different notes becomes much narrower in high positions, making the notes more challenging to locate and in some cases to distinguish by ear. Secondly, the much shorter sounding length of the string in very high positions is a challenge for the right arm and bow in sounding the instrument effectively. The finer (and more expensive) an instrument, the better able it is to sustain good tone right to the top of the fingerboard, at the highest pitches on the E string.
+
+All notes (except those below the open D) can be played on more than one string. This is a standard design feature of stringed instruments; however, it differs from the piano, which has only one location for each of its 88 notes. For instance, the note of open A on the violin can be played as the open A, or on the D string (in first to fourth positions) or even on the G string (very high up in sixth to ninth positions). Each string has a different tone quality, because of the different weights (thicknesses) of the strings and because of the resonances of other open strings. For instance, the G string is often regarded as having a very full, sonorous sound which is particularly appropriate to late Romantic music. This is often indicated in the music by the marking, for example, sul G or IV (a Roman numeral indicating to play on the fourth string; by convention, the strings are numbered from thinnest, highest pitch (I) to the lowest pitch (IV). Even without an explicit instructions in the score, an advanced violinist will use her/his discretion and artistic sensibility to select which string to play specific notes or passages.
+
+If a string is bowed or plucked without any finger stopping it, it is said to be an open string. This gives a different sound from a stopped string, since the string vibrates more freely at the nut than under a finger. Further, it is impossible to use vibrato fully on an open string (though a partial effect can be achieved by stopping a note an octave up on an adjacent string and vibrating that, which introduces an element of vibrato into the overtones). In the classical tradition, violinists will often use a string crossing or shift of position to allow them to avoid the change of timbre introduced by an open string, unless indicated by the composer. This is particularly true for the open E which is often regarded as having a harsh sound. However, there are also situations where an open string may be specifically chosen for artistic effect. This is seen in classical music which is imitating the drone of an organ (J. S. Bach, in his Partita in E for solo violin, achieved this), fiddling (e.g., Hoedown) or where taking steps to avoid the open string is musically inappropriate (for instance in Baroque music where shifting position was less common). In quick passages of scales or arpeggios an open E string may simply be used for convenience if the note does not have time to ring and develop a harsh timbre. In folk music, fiddling and other traditional music genres, open strings are commonly used for their resonant timbre.
+
+Playing an open string simultaneously with a stopped note on an adjacent string produces a bagpipe-like drone, often used by composers in imitation of folk music. Sometimes the two notes are identical (for instance, playing a fingered A on the D string against the open A string), giving a ringing sort of "fiddling" sound. Playing an open string simultaneously with an identical stopped note can also be called for when more volume is required, especially in orchestral playing. Some classical violin parts have notes for which the composer requests the violinist to play an open string, because of the specific sonority created by an open string.
+
+Double stopping is when two separate strings are stopped by the fingers, and bowed simultaneously, producing a sixth, third, fifth, etc. Double-stops can be indicated in any position, though the widest interval that can be double-stopped in one position is an octave (with the first finger on the lower string and the fourth finger on the higher string). Nonetheless, intervals of tenths or even more are sometimes required to be double-stopped in advanced playing, resulting in a stretched left-hand position with the fingers extended. The term "double stop" is often used to encompass sounding an open string alongside a fingered note as well, even though only one finger stops the string.
+
+Where three or four more simultaneous notes are written, the violinist will typically "split" the chord, choosing the lower one or two notes to play first before promptly continuing onto the upper one or two notes. A "triple stop" with three simultaneous notes is possible in some circumstances. The bow will not naturally strike three strings at once, but if there is sufficient bow speed and pressure when the violinist "breaks" a three note chord, the bow hair can be bent  temporarily so all three can sound. This is accomplished with a heavy stroke, typically quite near the frog, and quite loud. Double stops in orchestra are occasionally marked divisi and divided between the players, with half of the musicians playing the lower note and the other half playing the higher note.. Playing double stops is common when the violins play accompaniment and another instrument or section plays melodically.
+
+In some genres of historically informed performance (usually of Baroque music and earlier), neither split-chord nor triple-stop chords are thought to be appropriate and violinists will arpeggiate all chords (and even what appear to be regular double stops), playing all or most notes individually as if they had been written as a slurred figure. In some musical styles, a sustained open string drone can be played during a passage mainly written on an adjacent string, to provide a basic accompaniment. This is more often seen in folk traditions than in classical music. However, with the development of modern violins, triple-stopping came more naturally due to the bridge being less curved.
+
+Vibrato is a technique of the left hand and arm in which the pitch of a note varies subtly in a pulsating rhythm. While various parts of the hand or arm may be involved in the motion, the end result is a movement of the fingertip bringing about a slight change in vibrating string length, which causes an undulation in pitch. Some violinists oscillate backwards, or lower in pitch from the actual note when using vibrato, since it is believed that perception favors the highest pitch in a varying sound.[31] Vibrato does little, if anything, to disguise an out-of-tune note; in other words, misapplied vibrato is a poor substitute for good intonation. Scales and other exercises meant to work on intonation are typically played without vibrato to make the work easier and more effective. Music students are often taught that unless otherwise marked in music, vibrato is assumed. However, it has to be noted that this is only a trend; there is nothing on the sheet music that compels violinists to add vibrato. This can be an obstacle to a classically trained violinist wishing to play in a style that uses little or no vibrato at all, such as baroque music played in period style and many traditional fiddling styles.
+
+Vibrato can be produced by a proper combination of finger, wrist and arm motions. One method, called hand vibrato, involves rocking the hand back at the wrist to achieve oscillation, while another method, arm vibrato, modulates the pitch by rocking at the elbow. A combination of these techniques allows a player to produce a large variety of tonal effects. The "when" and "what for" and "how much" of violin vibrato are artistic matters of style and taste. Different teachers, music schools and styles of music favour different vibrato styles. For example, overdone vibrato may become distracting. In acoustic terms, the interest that vibrato adds to the sound has to do with the way that the overtone mix[32] (or tone color, or timbre) and the directional pattern of sound projection change with changes in pitch. By "pointing" the sound at different parts of the room[33][34] in a rhythmic way, vibrato adds a "shimmer" or "liveliness" to the sound of a well-made violin. Vibrato is, in a large part, left to the discretion of the violinist.  Different types of vibrato will bring different moods to the piece, and the varying degrees and styles of vibrato are often characteristics that stand out in well-known violinists.
+
+A vibrato-like motion can sometimes be used to create a fast trill effect. To execute this effect, the finger above the finger stopping the note is placed very slightly off the string (firmly pressed against the finger stopping the string) and a vibrato motion is implemented. The second finger will lightly touch the string above the lower finger with each oscillation, causing the pitch to oscillate in a fashion that sounds like a mix between vide vibrato and a very fast trill. This gives a less defined transition between the higher and lower note, and is usually implemented by interpretative choice. This trill technique only works well for semi-tonal trills or trills in high positions (where the distance between notes is lessened), as it requires the trilling finger and the finger below it to be touching, limiting the distance that can be trilled. In very high positions, where the trilled distance is less than the width of the finger, a vibrato trill may be the only option for trill effects.
+
+A major scale (arco and pizzicato)
+Beginning of an A major scale with vibrato
+A major scale played col legno
+Natural harmonics of an A, E, and an A
+Artificial (false) harmonic of A7
+
+Lightly touching the string with a fingertip at a harmonic node, but without fully pressing the string, and then plucking or bowing the string, creates harmonics. Instead of the normal tone, a higher pitched note sounds.  Each node is at an integer division of the string, for example half-way or one-third along the length of the string. A responsive instrument will sound numerous possible harmonic nodes along the length of the string. Harmonics are marked in music either with a little circle above the note that determines the pitch of the harmonic, or by diamond-shaped note heads. There are two types of harmonics: natural harmonics and artificial harmonics (also known as false harmonics).
+
+Natural harmonics are played on an open string. The pitch of the open string when it is plucked or bowed is called the fundamental frequency.  Harmonics are also called overtones or partials. They occur at whole-number multiples of the fundamental, which is called the first harmonic.  The second harmonic is the first overtone (the octave above the open string), the third harmonic is the second overtone, and so on. The second harmonic is in the middle of the string and sounds an octave higher than the string's pitch.  The third harmonic breaks the string into thirds and sounds an octave and a fifth above the fundamental, and the fourth harmonic breaks the string into quarters sounding two octaves above the first. The sound of the second harmonic is the clearest of them all, because it is a common node with all the succeeding even-numbered harmonics (4th, 6th, etc.). The third and succeeding odd-numbered harmonics are harder to play because they break the string into an odd number of vibrating parts and do not share as many nodes with other harmonics.
+
+Artificial harmonics are more difficult to produce than natural harmonics, as they involve both stopping the string and playing a harmonic on the stopped note. Using the octave frame (the normal distance between the first and fourth fingers in any given position) with the fourth finger just touching the string a fourth higher than the stopped note produces the fourth harmonic, two octaves above the stopped note. Finger placement and pressure, as well as bow speed, pressure, and sounding point are all essential in getting the desired harmonic to sound. And to add to the challenge, in passages with different notes played as false harmonics, the distance between stopping finger and harmonic finger must constantly change, since the spacing between notes changes along the length of the string.
+
+The harmonic finger can also touch at a major third above the pressed note (the fifth harmonic), or a fifth higher (a third harmonic).  These harmonics are less commonly used; in the case of the major third, both the stopped note and touched note must be played slightly sharp otherwise the harmonic does not speak as readily.  In the case of the fifth, the stretch is greater than is comfortable for many violinists. In the general repertoire fractions smaller than a sixth are not used.  However, divisions up to an eighth are sometimes used and, given a good instrument and a skilled player, divisions as small as a twelfth are possible. There are a few books dedicated solely to the study of violin harmonics. Two comprehensive works are Henryk Heller's seven-volume Theory of Harmonics, published by Simrock in 1928, and Michelangelo Abbado's five-volume Tecnica dei suoni armonici published by Ricordi in 1934.
+
+Elaborate passages in artificial harmonics can be found in virtuoso violin literature, especially of the 19th and early 20th centuries. Two notable examples of this are an entire section of Vittorio Monti's Csárdás and a passage towards the middle of the third movement of Pyotr Ilyich Tchaikovsky's Violin Concerto. A section of the third movement of Paganini's Violin Concerto No. 1 consists of double-stopped thirds in harmonics.
+
+When strings are worn, dirty and old, the harmonics may no longer be accurate in pitch. For this reason, violinists change their strings regularly.
+
+The strings may be sounded by drawing the hair of the bow held by the right hand across them (arco) or by plucking them (pizzicato) most often with the right hand. In some cases, the violinist will pluck strings with the left hand. This is done to facilitate transitions from pizzicato to arco playing. It is also used in some virtuoso showpieces. Left hand pizzicato is usually done on open strings. Pizzicato is used on all of the violin family instruments; however, the systematic study of advanced pizzicato techniques is most developed in jazz bass, a style in which the instrument is almost exclusively plucked.
+
+The right arm, hand, and bow and the bow speed are responsible for tone quality, rhythm, dynamics, articulation, and most (but not all) changes in timbre. The player draws the bow over the string, causing the string to vibrate and produce a sustained tone. The bow is a wooden stick with tensioned horsetail hair, which has been rosined with a bar of rosin. The natural texture of the horsehair and the stickiness of the rosin help the bow to "grip" the string, and thus when the bow is drawn over the string, the bow causes the string to sound a pitch.
+
+Bowing can be used to produce long sustained notes or melodies. With a string section, if the players in a section change their bows at different times, a note can seem to be endlessly sustainable. As well, the bow can be used to play short, crisp little notes, such as repeated notes, scales and arpeggios, which provide a propulsive rhythm in many styles of music.
+
+The most essential part of bowing technique is the bow grip. It is usually with the thumb bent in the small area between the frog and the winding of the bow. The other fingers are spread somewhat evenly across the top part of the bow. The pinky finger is curled with the tip of the finger placed on the wood next to the screw. The violin produces louder notes with greater bow speed or more weight on the string.  The two methods are not equivalent, because they produce different timbres; pressing down on the string tends to produce a harsher, more intense sound. One can also achieve a louder sound by placing the bow closer to the bridge.
+
+The sounding point where the bow intersects the string also influences timbre (or "tone colour"). Playing close to the bridge (sul ponticello) gives a more intense sound than usual, emphasizing the higher harmonics; and playing with the bow over the end of the fingerboard (sul tasto) makes for a delicate, ethereal sound, emphasizing the fundamental frequency. Dr. Suzuki referred to the sounding point as the Kreisler highway; one may think of different sounding points as lanes in the highway.
+
+Various methods of attack with the bow produce different articulations. There are many bowing techniques that allow for every range of playing style and many teachers, players, and orchestras spend a lot of time developing techniques and creating a unified technique within the group. These techniques include legato-style bowing (a smooth, connected, sustained sound suitable for melodies), collé, and a variety of bowings which produce shorter notes, including ricochet, sautillé, martelé, spiccato, and staccato.
+
+A note marked pizz. (abbreviation for pizzicato) in the written music is to be played by plucking the string with a finger of the right hand rather than by bowing. (The index finger is most commonly used here.) Sometimes in orchestra parts or virtuoso solo music where the bow hand is occupied (or for show-off effect), left-hand pizzicato will be indicated by a + (plus sign) below or above the note.  In left-hand pizzicato, two fingers are put on the string; one (usually the index or middle finger) is put on the correct note, and the other (usually the ring finger or little finger) is put above the note. The higher finger then plucks the string while the lower one stays on, thus producing the correct pitch. By increasing the force of the pluck, one can increase the volume of the note that the string is producing. Pizzicato is used in orchestral works and in solo showpieces. In orchestral parts, violinists often have to make very quick shifts from arco to pizzicato, and vice versa.
+
+A marking of col legno (Italian for "with the wood") in the written music calls for striking the string(s) with the stick of the bow, rather than by drawing the hair of the bow across the strings.  This bowing technique is somewhat rarely used, and results in a muted percussive sound. The eerie quality of a violin section playing col legno is exploited in some symphonic pieces, notably the "Witches' Dance" of the last movement of Berlioz's Symphonie Fantastique. Saint-Saëns's symphonic poem Danse Macabre includes the string section using the col legno technique to imitate the sound of dancing skeletons. "Mars" from Gustav Holst's "The Planets" uses col legno to play a repeated rhythm in 54 time signature. Benjamin Britten's The Young Person's Guide to the Orchestra demands its use in the "Percussion" Variation. Dmitri Shostakovich uses it in his Fourteenth Symphony in the movement 'At the Sante Jail'. Some violinists, however, object to this style of playing as it can damage the finish and impair the value of a fine bow, but most of such will compromise by using a cheap bow for at least the duration of the passage in question.
+
+A smooth and even stroke during which bow speed and weight are the same from beginning of the stroke to the end.[35]
+
+Literally hammered, a strongly accented effect produced by releasing each bowstroke forcefully and suddenly. Martelé can be played in any part of the bow. It is sometimes indicated in written music by an arrowhead.
+
+Tremolo is the very rapid repetition (typically of a single note, but occasionally of multiple notes), usually played at the tip of the bow. Tremolo is marked with three short, slanted lines across the stem of the note. Tremolo is often used as a sound effect in orchestral music, particularly in the Romantic music era (1800-1910) and in opera music.
+
+Attaching a small metal, rubber, leather, or wooden device called a mute, or sordino, to the bridge of the violin gives a softer, more mellow tone, with fewer audible overtones; the sound of an entire orchestral string section playing with mutes has a hushed quality. The mute changes both the loudness and the timbre ("tone colour") of a violin. The conventional Italian markings for mute usage are con sord., or con sordino, meaning 'with mute'; and senza sord., meaning 'without mute'; or via sord., meaning 'mute off'.
+
+Larger metal, rubber, or wooden mutes are widely available, known as practice mutes or hotel mutes.  Such mutes are generally not used in performance, but are used to deaden the sound of the violin in practice areas such as hotel rooms. (For practicing purposes there is also the mute violin, a violin without a sound box.) Some composers have used practice mutes for special effect, for example, at the end of Luciano Berio's Sequenza VIII for solo violin.
+
+Since the Baroque era, the violin has been one of the most important of all instruments in classical music, for several reasons.  The tone of the violin stands out above other instruments, making it appropriate for playing a melody line.  In the hands of a good player, the violin is extremely agile, and can execute rapid and difficult sequences of notes.
+
+Violins make up a large part of an orchestra, and are usually divided into two sections, known as the first and second violins. Composers often assign the melody to the first violins, typically a more difficult part using higher positions, while second violins play harmony, accompaniment patterns or the melody an octave lower than the first violins. A string quartet similarly has parts for first and second violins, as well as a viola part, and a bass instrument, such as the cello or, rarely, the double bass.
+
+The earliest references to jazz performance using the violin as a solo instrument are documented during the first decades of the 20th century. Joe Venuti, one of the first jazz violinists, is known for his work with guitarist Eddie Lang during the 1920s. Since that time there have been many improvising violinists including Stéphane Grappelli, Stuff Smith, Eddie South, Regina Carter, Johnny Frigo, John Blake, Adam Taubitz, Leroy Jenkins, and Jean-Luc Ponty. While not primarily jazz violinists, Darol Anger and Mark O'Connor have spent significant parts of their careers playing jazz.
+The Swiss-Cuban violinist Yilian Cañizares mixes jazz with Cuban music.[36]
+
+Violins also appear in ensembles supplying orchestral backgrounds to many jazz recordings.
+
+The Indian violin, while essentially the same instrument as that used in Western music, is different in some senses.[37] The instrument is tuned so that the IV and III strings (G and D on a western-tuned violin) and the II and I (A and E) strings are sa–pa (do–sol) pairs and sound the same but are offset by an octave, resembling common scordatura or fiddle cross-tunings such as G–D–G–D or A–E–A–E. The tonic sa (do) is not fixed, but variably tuned to accommodate the vocalist or lead player. The way the musician holds the instrument varies from Western to Indian music. In Indian music the musician sits on the floor cross-legged with the right foot out in front of them. The scroll of the instrument rests on the foot. This position is essential to playing well due to the nature of Indian music. The hand can move all over the fingerboard and there is no set position for the left hand, so it is important for the violin to be in a steady, unmoving position.
+
+Up through at least the 1970s, most types of popular music used bowed string sections. They were extensively used in popular music throughout the 1920s and early 1930s. With the rise of swing music, however, from 1935 to 1945, the string sound was often used to add to the fullness of big band music. Following the swing era, from the late 1940s to the mid-1950s, strings began to be revived in traditional pop music. This trend accelerated in the late 1960s, with a significant revival of the use of strings, especially in soul music. Popular Motown recordings of the late 1960s and 1970s relied heavily on strings as part of their trademark texture. The rise of disco music in the 1970s continued this trend with the heavy use of string instruments in popular disco orchestras (e.g., Love Unlimited Orchestra, Biddu Orchestra, Monster Orchestra, Salsoul Orchestra, MFSB).[citation needed]
+
+With the rise of electronically created music in the 1980s, violins declined in use, as synthesized string sounds played by a keyboardist with a synthesizer took their place. However, while the violin has had very little usage in mainstream rock music, it has some history in progressive rock (e.g., Electric Light Orchestra, King Crimson, Kansas, Gentle Giant). The 1973 album Contaminazione by Italy's RDM plays violins off against synthesizers at its finale ("La grande fuga").[citation needed] The instrument has a stronger place in modern jazz fusion bands, notably The Corrs.  The fiddle is sometimes a part of British folk rock music, as exemplified by the likes of Fairport Convention and Steeleye Span.[citation needed]
+
+The popularity of crossover music beginning in the last years of the 20th century has brought the violin back into the popular music arena, with both electric and acoustic violins being used by popular bands. Dave Matthews Band features violinist Boyd Tinsley.  The Flock featured violinist Jerry Goodman who later joined the jazz-rock fusion band, The Mahavishnu Orchestra.  James' Saul Davies, who is also a guitarist, was enlisted by the band as a violinist. For their first three albums and related singles, the British group No-Man made extensive use of electric and acoustic solo violin as played by band member Ben Coleman (who played violin exclusively).[citation needed]
+
+Pop-Punk band Yellowcard has made a mainstay of violin in its music. Violinist Sean Mackin has been a member of the band since 1997. Los Salvadores also combine punk and ska influences with a violin.[citation needed] Doom metal band My Dying Bride have used violin as a part of their line-up throughout many of their albums.[citation needed] The violin appears prominently in the music of Spanish folk metal group Mägo de Oz (for example, in their 1998 hit "Molinos de viento"). The violinist (Carlos Prieto a.k.a. "Mohamed") has been one of the group's most popular members with fans since 1992.[citation needed] The instrument is also used often in symphonic metal, particularly by bands such as Therion, Nightwish, Within Temptation, Haggard, and Epica, although it can also be found in Gothic Metal bands such as Tristania and Theater of Tragedy.[citation needed] The alternative rock band Hurt's vocalist plays violin for the band, making them one of few rock bands to feature violin without hiring a session worker.[citation needed] The folk metal band Ithilien use violin extensively along their discography.[38] Progressive metal band Ne Obliviscaris feature a violin player, Tim Charles, in their line-up.[39]
+
+Independent artists, such as Owen Pallett, The Shondes, and Andrew Bird, have also spurred increased interest in the instrument.[40] Indie bands have often embraced new and unusual arrangements, allowing them more freedom to feature the violin than many mainstream musical artists.  It has been used in the post-rock genre by bands such as A Genuine Freakshow, Sigur Rós, Zox, Broken Social Scene, and A Silver Mt. Zion. The electric violin has even been used by bands like The Crüxshadows within the context of keyboard based music.[citation needed] Lindsey Stirling plays the violin in conjunction with electronic/dubstep/trance rifts and beats.[41][citation needed]
+
+Eric Stanley improvises on the violin with hip hop music/pop/classical elements and instrumental beats.[42][43] The successful indie rock and baroque pop band Arcade Fire use violins extensively in their arrangements.[44] Indian, Turkish, and Arabic pop music is filled with the sound of violins, both soloists and ensembles.[citation needed]
+
+Like many other instruments used in classical music, the violin descends from remote ancestors that were used for folk music.  Following a stage of intensive development in the late Renaissance, largely in Italy, the violin had improved (in volume, tone, and agility), to the point that it not only became a very important instrument in art music, but proved highly appealing to folk musicians as well, ultimately spreading very widely, sometimes displacing earlier bowed instruments. Ethnomusicologists have observed its widespread use in Europe, Asia, and the Americas.
+
+When played as a folk instrument, the violin is usually referred to in English as a fiddle (although the term fiddle can be used informally no matter what the genre of music). Worldwide, there are various stringed instruments such as the wheel fiddle and Apache fiddle that are also called "fiddles". Fiddle music differs from classical in that the tunes are generally considered dance music,[45] and various techniques, such as droning, shuffling, and ornamentation specific to particular styles are used. In many traditions of folk music, the tunes are not written but are memorized by successive generations of musicians and passed on[45] in what is known as the oral tradition. Many old-time pieces call for cross-tuning, or using tunings other than standard GDAE. Some players of American styles of folk fiddling (such as bluegrass or old-time) have their bridge's top edge cut to a slightly flatter curve, making techniques such as a "double shuffle" less taxing on the bow arm, as it reduces the range of motion needed for alternating between double stops on different string pairs. Fiddlers who use solid steel core strings may prefer to use a tailpiece with fine tuners on all four strings, instead of the single fine tuner on the E string used by many classical players.
+
+As well as the Arabic rababah, the violin has been used in Arabic music.
+
+Electric violins have a magnetic or piezoelectric pickup that converts string vibration to an electric signal. A patch cable or wireless transmitter sends the signal to an amplifier of a PA system. Electric violins are usually constructed as such, but a pickup can be added to a conventional acoustic violin. An electric violin with a resonating body that produces listening-level sound independently of the electric elements can be called an electro-acoustic violin. To be effective as an acoustic violin, electro-acoustic violins retain much of the resonating body of the violin, and often resemble an acoustic violin or fiddle.  The body may be finished in bright colors and made from alternative materials to wood. These violins may need to be hooked up to an instrument amplifier or PA system.  Some types come with a silent option that allows the player to use headphones that are hooked up to the violin. The first specially built electric violins date back to 1928 and were made by Victor Pfeil, Oskar Vierling, George Eisenberg, Benjamin Miessner, George Beauchamp, Hugo Benioff and Fredray Kislingbury. These violins can be plugged into effect units, just like an electric guitar, including distortion, wah-wah pedal and reverb. Since electric violins do not rely on string tension and resonance to amplify their sound they can have more strings. For example, five-stringed electric violins are available from several manufacturers, and a seven string electric violin (with three lower strings encompassing the cello's range) is also available.[46] The majority of the first electric violinists were musicians playing jazz fusion (e.g., Jean-Luc Ponty) and popular music.
+
+Violin authentication is the process of determining the maker and manufacture date of a violin. This process is similar to that used to determine the provenance of art works.  As significant value may be attached to violins made either by specific makers or at specific times and locations, forgery and other methods of fraudulent misrepresentation can be used to inflate the value of an instrument.

en/6003.html.txt

@@ -0,0 +1,201 @@
+Coordinates: 38°N 79°W / 38°N 79°W / 38; -79
+
+Virginia (/vərˈdʒɪniə/ (listen)), officially the Commonwealth of Virginia, is a state in the Southeastern[4] and Mid-Atlantic[5] regions of the United States located between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth are shaped by the Blue Ridge Mountains and the Chesapeake Bay, which provide habitat for much of its flora and fauna. The capital of the Commonwealth is Richmond; Virginia Beach is the most populous city, and Fairfax County is the most populous political subdivision. The Commonwealth's estimated population as of 2019[update] is over 8.54 million.[6]
+
+The area's history begins with several indigenous groups, including the Powhatan. In 1607 the London Company established the Colony of Virginia as the first permanent English colony in the New World. Virginia's state nickname, the Old Dominion, is a reference to this status. Slave labor and the land acquired from displaced Native American tribes each played a significant role in the colony's early politics and plantation economy. Virginia was one of the 13 Colonies in the American Revolution. In the American Civil War, Virginia's Secession Convention resolved to join the Confederacy while the First Wheeling Convention resolved to remain in the Union, leading to a split that created West Virginia. Although the Commonwealth was under one-party rule for nearly a century following Reconstruction, both major national parties are competitive in modern Virginia.[7]
+
+Virginia's state legislature is the Virginia General Assembly, which was established in 1619 and is the oldest continuous law-making body in North America. It is made up of a 40-member Senate and a 100-member House of Delegates.[8] The state government is unique in how it treats cities and counties equally, manages local roads, and prohibits governors from serving consecutive terms. Virginia's economy has many sectors: agriculture in the Shenandoah Valley; federal agencies in Northern Virginia, including the headquarters of the U.S. Department of Defense and Central Intelligence Agency; and military facilities in Hampton Roads, the site of the region's main seaport.
+
+Virginia has a total area of 42,774.2 square miles (110,784.7 km2), including 3,180.13 square miles (8,236.5 km2) of water, making it the 35th-largest state by area.[9] Virginia is bordered by Maryland and Washington, D.C. to the north and east; by the Atlantic Ocean to the east; by North Carolina to the south; by Tennessee to the southwest; by Kentucky to the west; and by West Virginia to the north and west. Virginia's boundary with Maryland and Washington, D.C. extends to the low-water mark of the south shore of the Potomac River.[10]
+
+The state's southern border is defined as 36°30' north latitude, though surveyor error in the 1700s led to deviations of as much as three arcminutes.[11] From 1802 to 1803, a commission appointed by Virginia and Tennessee surveyed the area and set their border as a line from the summit of White Top Mountain to the top of the Cumberland Mountains. Errors discovered in 1856 led Virginia to propose a new surveying commission in 1871, but in 1893 the U.S. Supreme Court decided in favor of the 1803 line in the case Virginia v. Tennessee.[12][13] One result of this is the division of the city of Bristol between the two states.[14]
+
+The Chesapeake Bay separates the contiguous portion of the Commonwealth from the two-county peninsula of Virginia's Eastern Shore. The bay was formed from the drowned river valleys of the Susquehanna River and the James River.[15] Many of Virginia's rivers flow into the Chesapeake Bay, including the Potomac, Rappahannock, York, and James, which create three peninsulas in the bay.[16] Sea level rise has eroded the land on Virginia's islands, which include Tangier Island in the bay and Chincoteague, one of 23 barrier islands on the Atlantic coast.[17][18]
+
+The Tidewater is a coastal plain between the Atlantic coast and the fall line. It includes the Eastern Shore and major estuaries of Chesapeake Bay. The Piedmont is a series of sedimentary and igneous rock-based foothills east of the mountains which were formed in the Mesozoic era.[20] The region, known for its heavy clay soil, includes the Southwest Mountains around Charlottesville.[21] The Blue Ridge Mountains are a physiographic province of the Appalachian Mountains with the highest points in the commonwealth, the tallest being Mount Rogers at 5,729 feet (1,746 m).[2] The Ridge and Valley region is west of the mountains and includes the Great Appalachian Valley. The region is carbonate rock based and includes Massanutten Mountain.[22] The Cumberland Plateau and the Cumberland Mountains are in the southwest corner of Virginia, south of the Allegheny Plateau. In this region, rivers flow northwest, with a dendritic drainage system, into the Ohio River basin.[23]
+
+The Virginia Seismic Zone has not had a history of regular earthquake activity. Earthquakes are rarely above 4.5 in magnitude, because Virginia is located away from the edges of the North American Plate. A 5.8 magnitude earthquake struck central Virginia on August 23, 2011, near Mineral, and was the state's largest in at least a century.[24] Due to the area's geologic properties, the earthquake was felt from Northern Florida to Southern Ontario.[25] 35 million years ago, a bolide impacted what is now eastern Virginia. The resulting Chesapeake Bay impact crater may explain what earthquakes and subsidence the region does experience.[26]
+
+Coal mining takes place in the three mountainous regions at 45 distinct coal beds near Mesozoic basins.[27] More than 64 million tons of other non-fuel resources, such as slate, kyanite, sand, or gravel, were also mined in Virginia in 2018[update].[28] The commonwealth's carbonate rock is filled with more than 4,000 caves, ten of which are open for tourism, including the popular Luray Caverns and Skyline Caverns.[29]
+
+Virginia has a humid subtropical climate that transitions to humid continental west of the Blue Ridge Mountains.[30] Seasonal extremes vary from average lows of 25 °F (−4 °C) in January to average highs of 86 °F (30 °C) in July.[31] The Atlantic Ocean and Gulf Stream have a strong effect on eastern and southeastern coastal areas of the commonwealth, making the climate there warmer and more constant. Most of Virginia's recorded extremes in temperature and precipitation have occurred in the Blue Ridge Mountains and areas west.[32] Virginia receives an average of 43.34 inches (110 cm) of precipitation annually,[31] with the Shenandoah Valley being the state's driest region due to the mountains on either side.[32]
+
+Virginia has around 35–45 days with thunderstorms annually, and storms are common in the late afternoon and evenings between April and September.[33] These months are also the most common for tornadoes, 19 of which touched down in the state in 2019.[34] Hurricanes and tropical storms can occur from August to October, and though they typically impact coastal regions, the deadliest natural disaster in Virginia was Hurricane Camille, which killed over 150 people in 1969, mainly inland in Nelson County.[32][35] Between December and March, cold-air damming caused by the Appalachian Mountains can lead to significant snowfalls across the state, such as the January 2016 blizzard, which created the state's highest recorded snowfall of 36.6 inches (93 cm) near Bluemont.[36][37] Virginia only received 13.1 inches (33 cm) of snow during winter 2018–19, just above the state's average of 10 inches (25 cm).[38]
+
+Climate change in Virginia is leading to higher temperatures year-round as well as more heavy rain and flooding events.[39] Urban heat islands can be found in many Virginia cities and suburbs, particularly in neighborhoods linked to historic redlining.[40] Arlington had the most code orange days in 2019 for high ozone pollution in the air, with 12, followed by Fairfax County with 7.[41] Exposure of particulate matter in Virginia's air has decreased 49% from 13.5 micrograms per cubic meter in 2003 to 6.9 in 2019.[42] The closure and conversion of coal power plants in Virginia and the Ohio Valley region has reduced haze in the mountains, which peaked in 1998.[43] Virginia's 6 coal power plants must shut down by 2025,[44] and current plans call for 30 percent of the state's electricity to be renewable by 2030 and for all of it to be carbon-free by 2050.[45]
+
+Forests cover 62 percent of Virginia as of 2019[update], of which 78 percent is considered hardwood forest, meaning that trees in Virginia are primarily deciduous and broad-leaved. The other 22 percent is pine, with Loblolly and shortleaf pine dominating much of central and eastern Virginia.[46] In the western and mountainous parts of the commonwealth, oak and hickory are most common, while lower altitudes are more likely to have small but dense stands of moisture-loving hemlocks and mosses in abundance.[32] Gypsy moth infestations in oak trees and the blight in chestnut trees have decreased both of their numbers, leaving more room for hickory and invasive ailanthus trees.[47][32] In the lowland tidewater and Piedmont, yellow pines tend to dominate, with bald cypress wetland forests in the Great Dismal and Nottoway swamps.[46] Other common trees and plants include red bay, wax myrtle, dwarf palmetto, tulip poplar, mountain laurel, milkweed, daisies, and many species of ferns. The largest areas of wilderness are along the Atlantic coast and in the western mountains, where the largest populations of trillium wildflowers in North America are found.[32][48]
+
+Virginia is home to more than one million white-tailed deer, whose population have rebounded from an estimated 25,000 to 50,000 during the Great Depression.[49] Native carnivorans include black bears, bobcats, coyotes, both gray and red foxes, raccoons, and skunks. Rodents include groundhogs, weasels, nutria, beavers, both gray squirrels and fox squirrels, chipmunks, and Allegheny woodrats, while bats include brown bats and the Virginia big-eared bat, the state mammal.[50] The Virginia opossum is also the only marsupial native to the United States and Canada,[51] and the native Appalachian cottontail was recognized as a distinct species of rabbit in 1992.[52]
+
+Virginia's bird fauna, as of 1995, consists of some 422 species, of which 359 are regularly occurring, 41 are accidental (vagrant), 20 are hypothetical, and two are extinct; of the regularly occurring species, 214 have bred in Virginia, while the rest are winter residents or transients in Virginia.[53] There are no species of bird endemic to the state.[53] Audubon recognizes 21 Important Bird Areas in the Virginia.[54] Peregrine falcons, whose numbers dramatically declined due to DDT pesticide poisoning in the middle of the 20th century, are the focus of conservation efforts in the state; as of 2017, Virginia had 31 breeding pairs of the bird, and a reintroduction program in Shenandoah National Park was underway.[55]
+
+Virginia has 226 species of freshwater fish, from 25 families; the state's diverse array of fish species is attributable to its varied and humid climate, physiography, river system interconnections, and lack of Pleistocene glaciers. For example, the state is home to Eastern blacknose dace and sculpin (on the Appalachian Plateau); smallmouth bass and redhorse sucker (in the Ridge and Valley region); brook trout, rainbow trout, brown trout, and the Kanawha darter (in the Blue Ridge); stripeback darter and Roanoke Bass (in the Piedmont); and swampfish, bluespotted sunfish, and pirate perch (on the Coastal Plain).[56] The Chesapeake Bay is host to many species, including blue crabs, clams, oysters, rockfish, as well as the invasive blue catfish.[57] Running brooks with rocky bottoms are often inhabited by plentiful amounts of crayfish.[32] Amphibians found in Virginia include the Cumberland Plateau salamander and Eastern hellbender.[58]
+
+Virginia has 30 National Park Service units, such as Great Falls Park and the Appalachian Trail, and one national park, Shenandoah National Park.[59] Shenandoah was established in 1935 and encompasses the scenic Skyline Drive. Almost forty percent (79,579 acres or 322.04 km2) of the park's total 199,173 acres (806.02 km2) area has been designated as wilderness under the National Wilderness Preservation System.[60] Virginia also has 38 Virginia state parks, 3 undeveloped parks, and 63 natural areas, totaling 127,000 acres (51,000 ha), of which approximately 70,000 acres (28,000 ha) are in state parks.[61] All are managed by the Virginia Department of Conservation and Recreation except for Breaks Interstate Park.[62] which lies on the Virginia-Kentucky border and is one of only two inter-state parks in the United States.[63] There are 22 state forests and other state lands managed by the Virginia Department of Forestry, totaling 67,920 acres (27,490 ha).[64] The Chesapeake Bay is not a national park, but is protected by both state and federal legislation; the jointly run Chesapeake Bay Program which conducts restoration on the bay and its watershed. The Great Dismal Swamp National Wildlife Refuge extends into North Carolina, as does the Back Bay National Wildlife Refuge, which marks the beginning of the Outer Banks.[65]
+
+Virginia celebrated its quadricentennial year in 2007, marking 400 years since the establishment of the Jamestown Colony. The observances highlighted contributions from Native Americans, Africans, and Europeans, each of which had a significant part in shaping Virginia's history.[67][68] Warfare, including among these groups, has also had an important role. Virginia was a focal point in conflicts from the French and Indian War, the American Revolution and the Civil War, to the Cold War and the War on Terrorism.[69] Fictionalized stories about the early colony, in particular the story of Pocahontas and John Smith, first became popular in the period after the Revolutionary War, and together with other myths surrounding George Washington's childhood and plantation elite in the antebellum period became touchstones of Virginian and American culture and helped shape the state's historic politics and beliefs.[70][66]
+
+The first people are estimated to have arrived in Virginia over 12,000 years ago.[71] By 5,000 years ago more permanent settlements emerged, and farming began by 900 AD. By 1500, the Algonquian peoples had founded towns such as Werowocomoco in the Tidewater region, which they referred to as Tsenacommacah. The other major language groups in the area were the Siouan to the west, and the Iroquoians, who included the Nottoway and Meherrin, to the north and south. After 1570, the Algonquians consolidated under Chief Powhatan in response to threats from these other groups on their trade network.[72] Powhatan controlled more than 30 smaller tribes and more than 150 settlements, who shared a common Virginia Algonquian language. In 1607, the native Tidewater population was between 13,000 and 14,000.[73]
+
+Several European expeditions, including a group of Spanish Jesuits, explored the Chesapeake Bay during the 16th century.[74] In 1583, Queen Elizabeth I of England granted Walter Raleigh a charter to plant a colony north of Spanish Florida.[75] In 1584, Raleigh sent an expedition to the Atlantic coast of North America.[76] The name "Virginia" may have been suggested then by Raleigh or Elizabeth, perhaps noting her status as the "Virgin Queen", and may also be related to a native phrase, "Wingandacoa", or name, "Wingina".[77] Initially the name applied to the entire coastal region from South Carolina to Maine, plus the island of Bermuda.[78] The London Company was incorporated as a joint stock company by the proprietary Charter of 1606, which granted land rights to this area. The company financed the first permanent English settlement in the "New World", Jamestown. Named for King James I, it was founded in May 1607 by Christopher Newport.[79] In 1619, colonists took greater control with an elected legislature called the House of Burgesses. With the bankruptcy of the London Company in 1624, the settlement was taken into royal authority as an English crown colony.[80]
+
+Life in the colony was perilous, and many died during the Starving Time in 1609 and the Anglo-Powhatan Wars, including the Indian massacre of 1622, which fostered the colonists' negative view of all tribes.[81] By 1624, only 3,400 of the 6,000 early settlers had survived.[82] However, European demand for tobacco fueled the arrival of more settlers and servants.[83] The headright system tried to solve the labor shortage by providing colonists with land for each indentured servant they transported to Virginia.[84] African workers were first imported to Jamestown in 1619 initially under the rules of indentured servitude. The shift to a system of African slavery in Virginia was propelled by the legal cases of John Punch, who was sentenced to lifetime slavery in 1640 for attempting to escape his servitude, and of John Casor, who was claimed by Anthony Johnson as his servant for life in 1655.[85] Slavery first appears in Virginia statutes in 1661 and 1662, when a law made it hereditary based on the mother's status.[86]
+
+Tensions and the geographic differences between the working and ruling classes led to Bacon's Rebellion in 1676, by which time current and former indentured servants made up as much as eighty percent of the population.[87] Rebels, largely from the colony's frontier, were also opposed to the conciliatory policy towards native tribes, and one result of the rebellion was the signing at Middle Plantation of the Treaty of 1677, which made the signatory tribes tributary states and was part of a pattern of appropriating tribal land by force and treaty. Middle Plantation saw the founding of The College of William & Mary in 1693 and was renamed Williamsburg as it became the colonial capital in 1699.[88] In 1747, a group of Virginian speculators formed the Ohio Company, with the backing of the British crown, to start English settlement and trade in the Ohio Country west of the Appalachian Mountains.[89] France, which claimed this area as part of their colony of New France, viewed this as a threat, and the ensuing French and Indian War became part of the Seven Years' War (1756–1763). A militia from several British colonies, called the Virginia Regiment, was led by then-Lieutenant Colonel George Washington.[90]
+
+The British Parliament's efforts to levy new taxes following the French and Indian War were deeply unpopular in the colonies. In the House of Burgesses, opposition to taxation without representation was led by Patrick Henry and Richard Henry Lee, among others.[91] Virginians began to coordinate their actions with other colonies in 1773, and sent delegates to the Continental Congress the following year.[92] After the House of Burgesses was dissolved by the royal governor in 1774, Virginia's revolutionary leaders continued to govern via the Virginia Conventions. On May 15, 1776, the Convention declared Virginia's independence from the British Empire and adopted George Mason's Virginia Declaration of Rights, which was then included in a new constitution.[93] Another Virginian, Thomas Jefferson, drew upon Mason's work in drafting the national Declaration of Independence.[94]
+
+When the American Revolutionary War began, George Washington was selected to head the colonial army. During the war, the capital was moved to Richmond at the urging of Governor Thomas Jefferson, who feared that Williamsburg's coastal location would make it vulnerable to British attack.[95] In 1781, the combined action of Continental and French land and naval forces trapped the British army on the Virginia Peninsula, where troops under George Washington and Comte de Rochambeau defeated British General Cornwallis in the Siege of Yorktown. His surrender on October 19, 1781 led to peace negotiations in Paris and secured the independence of the colonies.[96]
+
+Virginians were instrumental in writing the United States Constitution. James Madison drafted the Virginia Plan in 1787 and the Bill of Rights in 1789.[94] Virginia ratified the Constitution on June 25, 1788. The three-fifths compromise ensured that Virginia, with its large number of slaves, initially had the largest bloc in the House of Representatives. Together with the Virginia dynasty of presidents, this gave the Commonwealth national importance. In 1790, both Virginia and Maryland ceded territory to form the new District of Columbia, though the Virginian area was retroceded in 1846.[97] Virginia is called the "Mother of States" because of its role in being carved into states such as Kentucky, which became the 15th state in 1792, and for the numbers of American pioneers born in Virginia.[98]
+
+In addition to agriculture, slave labor was increasingly used in mining, shipbuilding and other industries.[99] The execution of Gabriel Prosser in 1800, Nat Turner's slave rebellion in 1831 and John Brown's Raid on Harpers Ferry in 1859 marked the growing social discontent over slavery and its role in the plantation economy. By 1860, almost half a million people, roughly 31 percent of the total population of Virginia, were enslaved.[100] This division contributed to the start of the American Civil War.
+
+Virginia voted to secede from the United States on April 17, 1861, after the Battle of Fort Sumter and Abraham Lincoln's call for volunteers. On April 24, Virginia joined the Confederate States of America, which chose Richmond as its capital.[98] After the 1861 Wheeling Convention, 48 counties in the northwest separated to form a new state of West Virginia, which chose to remain loyal to the Union. Virginian general Robert E. Lee took command of the Army of Northern Virginia in 1862, and led invasions into Union territory, ultimately becoming commander of all Confederate forces. During the war, more battles were fought in Virginia than anywhere else, including Bull Run, the Seven Days Battles, Chancellorsville, and the concluding Battle of Appomattox Court House.[101] After the capture of Richmond in April 1865, the state capital was briefly moved to Lynchburg,[102] while the Confederate leadership fled to Danville.[103] Virginia was formally restored to the United States in 1870, due to the work of the Committee of Nine.[104]
+
+During the post-war Reconstruction era, Virginia adopted a constitution which provided for free public schools, and guaranteed political, civil, and voting rights.[105] The populist Readjuster Party ran an inclusive coalition until the conservative white Democratic Party gained power after 1883.[106] It passed segregationist Jim Crow laws and in 1902 rewrote the Constitution of Virginia to include a poll tax and other voter registration measures that effectively disenfranchised most African Americans and many poor European Americans.[107] Though their schools and public services were segregated and underfunded due to a lack of political representation, African Americans were able to unite in communities and take a greater role in Virginia society.[108]
+
+New economic forces also changed the Commonwealth. Virginian James Albert Bonsack invented the tobacco cigarette rolling machine in 1880 leading to new industrial scale production centered around Richmond. In 1886, railroad magnate Collis Potter Huntington founded Newport News Shipbuilding, which was responsible for building six World War I-era dreadnoughts, seven battleships, and 25 destroyers for the U.S. Navy from 1907 to 1923.[109] During the war, German submarines like U-151 attacked ships outside the port.[110] In 1926, Dr. W.A.R. Goodwin, rector of Williamsburg's Bruton Parish Church, began restoration of colonial-era buildings in the historic district with financial backing of John D. Rockefeller, Jr.[111] Though their project, like others in the state, had to contend with the Great Depression and World War II, work continued as Colonial Williamsburg became a major tourist attraction.[112]
+
+Protests started by Barbara Rose Johns in 1951 in Farmville against segregated schools led to the lawsuit Davis v. County School Board of Prince Edward County. This case, filed by Richmond natives Spottswood Robinson and Oliver Hill, was decided in 1954 with Brown v. Board of Education, which rejected the segregationist doctrine of "separate but equal". But, in 1958, under the policy of "massive resistance" led by the influential segregationist Senator Harry F. Byrd and his Byrd Organization, the Commonwealth prohibited desegregated local schools from receiving state funding.[113]
+
+The civil rights movement gained many participants in the 1960s. It achieved the moral force and support to gain passage of national legislation with the Civil Rights Act of 1964 and the Voting Rights Act of 1965. In 1964 the United States Supreme Court ordered Prince Edward County and others to integrate schools.[114] In 1967, the Court also struck down the state's ban on interracial marriage with Loving v. Virginia. From 1969 to 1971, state legislators under Governor Mills Godwin rewrote the constitution, after goals such as the repeal of Jim Crow laws had been achieved. In 1989, Douglas Wilder became the first African American elected as governor in the United States.[115]
+
+The Cold War led to the expansion of national defense government programs housed in offices in Northern Virginia near Washington, D.C., and correlative population growth.[116] The Central Intelligence Agency in Langley was involved in various Cold War events, including as the target of Soviet espionage activities. Also among the federal developments was the Pentagon, built during World War II as the headquarters for the Department of Defense. It was one of the targets of the September 11 attacks; 189 people died at the site when a jet passenger plane was flown into the building.[117] Mass shootings at Virginia Tech in 2007 and in Virginia Beach in 2019 led to passage of gun control measures in 2020.[118] Racial injustice and the presence of Confederate monuments in Virginia have also led to large demonstrations, including in August 2017, when a white supremacist drove his car into protesters, killing one, and in June 2020, when protests that were part of the larger Black Lives Matter movement brought about the removal of statues on Monument Avenue in Richmond and elsewhere.[119]
+
+Virginia is divided into 95 counties and 38 independent cities, the latter acting in many ways as county-equivalents.[120] This general method of treating cities and counties on par with each other is unique to Virginia; only three other independent cities exist elsewhere in the United States, each in a different state.[121] Virginia limits the authority of cities and counties to countermand laws expressly allowed by the Virginia General Assembly under what is known as Dillon's Rule.[122] In addition to independent cities, there are also incorporated towns which operate under their own governments, but are part of a county. Finally there are hundreds of unincorporated communities within the counties. Virginia does not have any further political subdivisions, such as villages or townships.
+
+Over 3.1 million people, 36 percent of Virginians, live in Northern Virginia, which is part of the larger Washington metropolitan area and the Northeast megalopolis.[123] Fairfax County is the most populous locality in the state, with more than 1.1 million residents, although that does not include its county seat Fairfax City, which is one of the independent cities.[124] Fairfax County has a major urban business and shopping center in Tysons Corner, Virginia's largest office market.[125] Neighboring Prince William County is Virginia's second most populous county, with a population exceeding 450,000, and is home to Marine Corps Base Quantico, the FBI Academy and Manassas National Battlefield Park. Loudoun County, with the county seat at Leesburg, is the fastest-growing county in the state.[124][126] Arlington County, the smallest self-governing county in the United States by land area, is an urban community organized as a county.[127]
+
+Richmond is the capital of Virginia, and its metropolitan area has a population over 1.2 million.[128] As of 2019[update], Virginia Beach is the most populous independent city in the Commonwealth, with Chesapeake and Norfolk second and third, respectively.[129] The three are part of the larger Hampton Roads metropolitan area, which has a population over 1.7 million people and is the site of the world's largest naval base, Naval Station Norfolk.[128][130] Suffolk, which includes a portion of the Great Dismal Swamp, is the largest city by area at 429.1 square miles (1,111 km2).[131] In western Virginia, Roanoke city and Montgomery County, part of the Blacksburg–Christiansburg metropolitan area, both have surpassed a population of over 100,000 since 2018.[132]
+
+The United States Census Bureau estimates that the state population was 8,535,519 on July 1, 2019, a 6.7 percent increase since the 2010 United States Census.[6] This includes an increase of 534,495 people into the Commonwealth since the 2010 census. Immigration from outside the United States resulted in a net increase of 159,627 people, and migration within the country produced a net increase of 155,205 people.[135] As of 2010[update], the center of population was located in Louisa County, near Richmond.[136]
+
+Aside from Virginia, the top birth state for Virginians is New York, having overtaken North Carolina in the 1990s, with the Northeast accounting for the largest number of migrants into the state by region.[137] The median age in 2018 was 38.4 years old, making the state just slightly older than the national average of 38.2.[138]
+
+The state's most populous ethnic group, Non-Hispanic whites, has declined as a proportion of population from 76 percent in 1990 to 61 percent in 2019, as other ethnicities have increased.[139][6] People of English heritage settled throughout the Commonwealth during the colonial period, and others of British and Irish heritage have since immigrated.[140] Those who identify on the census as having "American ethnicity" are predominantly of English descent, but have ancestors who have been in North America for so long they choose to identify simply as American.[141][142] Of the English immigrants to Virginia in the 17th century, three-fourths came as indentured servants.[143] The western mountains have many settlements that were founded by Scots-Irish immigrants before the American Revolution.[144][145] There are also sizable numbers of people of German descent in the northwestern mountains and Shenandoah Valley.[146] On the 2018 American Community Survey, eleven percent said they were of German ancestry.[147]
+
+The largest minority group in Virginia are African Americans, who include about one-fifth of the population.[6] Virginia was a major destination of the Atlantic slave trade, and the first generations of enslaved men, women and children were brought primarily from Angola and the Bight of Biafra. The Igbo ethnic group of what is now southern Nigeria were the single largest African group among slaves in Virginia.[148] Many African Americans also have European and Native American ancestry, often with asymmetrical male and female ancestry contribution.[149] Though the Black population was reduced by the Great Migration to northern industrial cities in the first half of the 20th century, since 1965 there has been a reverse migration of Blacks returning south.[150] According to the Pew Research Center, the state has the highest number of black-white interracial marriages in the United States,[151] and 3.1 percent of Virginians describe themselves as biracial.[6]
+
+More recent immigration in the late 20th century and early 21st century has resulted in new communities of Hispanics and Asians. Among international immigrants to Virginia, eleven percent were born in El Salvador, nine percent in India, six percent in South Korea and five percent each in Mexico and the Philippines, and 52 percent are U.S. citizens as of 2017[update].[152] As of 2019[update], 9.6 percent of Virginia's total population describe themselves as Hispanic or Latino, and 6.9 percent as Asian.[6] The state's Hispanic population rose by 92 percent from 2000 to 2010, with two-thirds of Hispanics in the state living in Northern Virginia.[153] Hispanic citizens in Virginia have higher median household incomes and educational attainment than the general state population.[154] Northern Virginia also has a significant population of Vietnamese Americans, whose major wave of immigration followed the Vietnam War.[155] Korean Americans have migrated more recently, attracted by the quality school system.[156] The Filipino American community has about 45,000 in the Hampton Roads area, many of whom have ties to the U.S. Navy and armed forces.[157]
+
+Additionally, 0.5 percent of Virginians are American Indian or Alaska Native, and 0.1 percent are Native Hawaiian or other Pacific Islander.[6] Virginia has extended state recognition to eleven Native American tribes resident in the state. Seven tribes also have federal recognition, including six that were recognized in 2018 after passage of bill named for activist Thomasina Jordan.[158][159] The Pamunkey and Mattaponi have reservations on tributaries of the York River in the Tidewater region.[160]
+
+American Community Survey five-year estimate
+
+As of 2010[update], 85.9% (6,299,127) of Virginia residents age five and older spoke English at home as a first language, while 14.1% (1,036,442) did not—6.4% (470,058) spoke Spanish, 0.8% (56,518) Korean, 0.6% (45,881) Vietnamese, 0.6% (42,418) Chinese (including Mandarin), and 0.6% (40,724) Tagalog.[161] English was passed as the Commonwealth's official language by statutes in 1981 and again in 1996, though the status is not mandated by the Constitution of Virginia.[162]
+
+The Piedmont region is known for its dialect's strong influence on Southern American English. While a more homogenized American English is found in urban areas, various accents are also used, including the Tidewater accent, the Old Virginia accent, and the anachronistic Elizabethan of Tangier Island.[163][164]
+
+Virginia is predominantly Christian and Protestant; Baptist denominations combined to form largest group with about 26 percent of the population as of 2014[update],[165] and around 763,655 total members as of 2010[update].[166] Baptist denominational groups in Virginia include the Baptist General Association of Virginia, with about 1,400 member churches, which supports both the Southern Baptist Convention and the moderate Cooperative Baptist Fellowship; and the Southern Baptist Conservatives of Virginia with more than 500 affiliated churches, which supports the Southern Baptist Convention.[167][168] Roman Catholics are the second-largest religious group with 673,853 members.[166] The Roman Catholic Diocese of Arlington includes most of Northern Virginia's Catholic churches, while the Diocese of Richmond covers the rest.
+
+The Virginia Conference is the regional body of the United Methodist Church in most of the Commonwealth, while the Holston Conference represents much of extreme Southwest Virginia. The Virginia Synod is responsible for the congregations of the Lutheran Church. Presbyterian, Pentecostal, Congregationalist, and Episcopalian adherents each comprised less than two percent of the population as of 2010[update].[166] The Episcopal Diocese of Virginia, Southern Virginia, and Southwestern Virginia support the various Episcopal churches.
+
+In November 2006, 15 conservative Episcopal churches voted to split from the Diocese of Virginia over the ordination of openly gay bishops and clergy in other dioceses of the Episcopal Church; these churches continue to claim affiliation with the larger Anglican Communion through other bodies outside the United States. Though Virginia law allows parishioners to determine their church's affiliation, the diocese claimed the secessionist churches' buildings and properties. The resulting property law case, ultimately decided in favor of the mainline diocese, was a test for Episcopal churches nationwide.[169]
+
+Among other religions, adherents of The Church of Jesus Christ of Latter-day Saints constitute one percent of the population, with two hundred congregations in Virginia as of 2017[update].[170] Fairfax Station is the site of the Ekoji Buddhist Temple, of the Jodo Shinshu school, and the Hindu Durga Temple. While the state's Jewish population is small, organized Jewish sites date to 1789 with Congregation Beth Ahabah.[171] Muslims are a growing religious group throughout the Commonwealth through immigration.[172] Megachurches in the Commonwealth include Thomas Road Baptist Church, Immanuel Bible Church, and McLean Bible Church.[173] Several Christian universities are also based in the state, including Regent University, Liberty University, and the University of Lynchburg.
+
+Virginia's economy has diverse sources of income, including local and federal government, military, farming and high-tech. Prior to the coronavirus recession, Virginia had 4.36 million people employed with an unemployment rate of 2.9 percent in March 2020,[174] but jobless claims due to the virus peaked in early April 2020, before falling slightly in May, when the state had 386,000 unemployed with a rate of 9.4 percent,[175] which was tied for the 11th-lowest nationwide.[176] The state's average earnings per job was $63,281, the 11th-highest nationwide,[177] and the gross domestic product (GDP) was $476.4 billion in 2018, the 13th-largest among U.S. states.[178] Canada is the state's leading international market, receiving 17.2 percent of exports.[179]
+
+Virginia has a median household income of $72,600, 11th-highest nationwide, and a poverty rate of 10.7 percent, 12th-lowest nationwide, as of 2018[update]. Montgomery County outside Blacksburg has the highest poverty rate in the state, with 28.5 percent falling below the U.S. Census poverty thresholds. Loudoun County meanwhile has the highest median household income in the nation, and the wider Northern Virginia region is among the highest-income regions nationwide.[180] As of 2013[update], six of the twenty highest-income counties in the United States, including the two highest,[181] as well as three of the fifty highest-income towns, are all located in Northern Virginia.[182] Though the Gini index shows Virginia has less income inequality than the national average,[183] the state's middle class is also smaller than the majority of states.[184]
+
+Virginia has the highest defense spending of any state per capita, providing the Commonwealth with around 900,000 jobs.[186][187] Approximately twelve percent of all U.S. federal procurement money is spent in Virginia, the second-highest amount after California.[187][188] Many Virginians work for federal agencies in Northern Virginia, which include the Central Intelligence Agency and the Department of Defense, as well as the National Science Foundation, the United States Geological Survey and the United States Patent and Trademark Office. Many others work for government contractors, including defense and security firms, which hold more than 15,000 federal contracts.[189]
+
+Virginia has one of the highest concentrations of veterans of any state,[190] and is second to California in total Department of Defense employees.[188][191] The Hampton Roads area has the largest concentration of military personnel and assets of any metropolitan area in the world,[192] including the largest naval base in the world, Naval Station Norfolk.[130] In its state government, Virginia employs 106,143 public employees, who combined have a median income of $44,656 as of 2013[update].[193]
+
+Virginia was home to 653,193 separate firms in the 2012 U.S. Census Survey of Business Owners, with 54% of those majority male-owned and 36.2% majority female-owned. Approximately 28.3% of firms were also majority minority-owned, and 11.7% were veteran-owned.[194] Twenty-one Fortune 500 companies are headquartered in Virginia as of 2019[update], with the largest companies by revenue being Freddie Mac, General Dynamics, and Capital One.[195] The largest by their number of employees are Dollar Tree in Chesapeake and Hilton Worldwide Holdings in McLean.[196]
+
+Virginia's business environment has been ranked highly by various publications. In 2019, CNBC named Virginia their Top State for Business, with its deductions being mainly for the high cost of living,[197] while Forbes magazine ranked it fourth, though number one in quality of life.[198] Additionally, in 2014 a survey of 12,000 small business owners found Virginia to be one of the most friendly states for small businesses.[199] Oxfam America however ranked Virginia last in their July 2018 ranking of best states to work in, largely due to a low minimum wage of $7.25, and the state's organized labor laws. Though the topic was debated during in the 2019–20 General Assembly session, Virginia has been a "right to work" state since 1947,[200] and an employment-at-will state since 1906.[201]
+
+Virginia has the highest concentration of technology workers of any state,[202] and the fourth-highest number of technology workers after California, Texas, and New York.[203] Computer chips became the state's highest-grossing export in 2006,[204] with a total export value of $694 million in 2019.[179] Northern Virginia, once considered the state's dairy capital, now hosts software, communication technology, defense contracting companies, particularly in the Dulles Technology Corridor and Tysons Corner areas. The state has the highest average and peak Internet speeds in the United States, with the third-highest worldwide.[205] Northern Virginia's data centers can carry up to seventy percent of the nation's Internet traffic,[206] and in 2015 the region was the largest and fastest growing data center market in the nation.[207][208]
+
+Tourism in Virginia supported an estimated 234,000 jobs in 2018, making tourism the state's fifth largest industry. It generated $26 billion, an increase 4.4 percent from 2017.[209] The state was eighth nationwide in domestic travel spending in 2018, with Arlington County the top tourist destination in the state by domestic spending, followed by Fairfax County, Loudoun County, and Virginia Beach.[210] Virginia also saw 1.1 million international tourists in 2018, a five percent increase from 2017.[211]
+
+As of 2017[update], agriculture occupied 28 percent of the land in Virginia with 7.8 million acres (12,188 sq mi; 31,565 km2) of farmland. Nearly 54,000 Virginians work on the state's 43,225 farms, which average 181 acres (0.28 sq mi; 0.73 km2). Though agriculture has declined significantly since 1960 when there were twice as many farms, it remains the largest single industry in Virginia, providing for over 334,000 jobs.[213] Soybeans were the most profitable crop in Virginia in 2017, ahead of corn and cut flowers as other leading agricultural products.[214] However, the ongoing China-U.S. trade war led many Virginia farmers to plant cotton instead of soybeans in 2019.[215] Though it is no longer the primary crop, Virginia is still the third-largest producer of tobacco in the United States.[213]
+
+Virginia is also the country's third-largest producer of seafood as of 2018[update], with sea scallops, oysters, Chesapeake blue crabs, menhaden, and hardshell clams as the largest seafood harvests by value, and France, Canada, and Hong Kong as the top export destinations.[216][217] Commercial fishing supports 18,220 jobs as of 2020[update], while recreation fishing supports another 5,893.[218] Eastern oyster harvests had increased from 23,000 bushels in 2001 to over 500,000 in 2013,[219] but fell to 248,347 in 2019 because of low salinity in coastal waters due to heavy spring rains.[220] Those same rains however made 2019 a record wine harvest for vineyards in the Northern Neck and along the Blue Ridge Mountains, which also attract 2.3 million tourists annually.[221][222] Virginia has the seventh-highest number of wineries in the nation, with 307 as of January 2020[update].[223] Cabernet franc and Chardonnay are the most grown varieties.[224]
+
+Virginia collects personal income tax from those with incomes above a filing threshold; there are five income brackets, with rates ranging from 2.0% to 5.75% of taxable income.[225][226] The state sales and use tax rate is 4.3%. There is an additional 1% local tax, for a total of a 5.3% combined sales tax on most Virginia purchases. The sales tax rate is  higher in three regions: Northern Virginia (6%), Hampton Roads (6%) and the Historic Triangle (7%).[227] Unlike the majority of states, Virginia collects sales tax on groceries, but at a lower rate than the general sales tax;[228] the sales tax for food and certain essential personal hygiene goods is 2.5%.[227]
+
+Virginia's property tax is set and collected at the local government level and varies throughout the Commonwealth. Real estate is also taxed at the local level based on one hundred percent of fair market value.[229] As of fiscal year 2018, the median real estate tax rate per $100 of assessed taxable value was $1.07 for cities, $0.67 for counties, and $0.17 for towns; town rates are lower because towns (unlike cities) have a narrow range of responsibilities and are subordinate to counties.[230] Of local government tax revenue, about 61% is generated from real property taxes; about 24% from tangible personal property, sales and use, and business license tax; and 15% from other taxes (such as restaurant meal taxes, public service corporation property tax, consumer utility tax, and hotel tax).[231]
+
+Virginia's culture was popularized and spread across America and the South by figures such as George Washington, Thomas Jefferson, and Robert E. Lee. Their homes in Virginia represent the birthplace of America and the South.[232] Modern Virginia culture has many sources, and is part of the culture of the Southern United States.[233] The Smithsonian Institution divides Virginia into nine cultural regions.[234]
+
+Besides the general cuisine of the Southern United States, Virginia maintains its own particular traditions. Virginia wine is made in many parts of the commonwealth.[222] Smithfield ham, sometimes called "Virginia ham", is a type of country ham which is protected by state law, and can be produced only in the town of Smithfield.[235] Virginia furniture and architecture are typical of American colonial architecture. Thomas Jefferson and many of the commonwealth's early leaders favored the Neoclassical architecture style, leading to its use for important state buildings. The Pennsylvania Dutch and their style can also be found in parts of the commonwealth.[146]
+
+Literature in Virginia often deals with the commonwealth's extensive and sometimes troubled past. The works of Pulitzer Prize winner Ellen Glasgow often dealt with social inequalities and the role of women in her culture.[236] Glasgow's peer and close friend James Branch Cabell wrote extensively about the changing position of gentry in the Reconstruction era, and challenged its moral code with Jurgen, A Comedy of Justice.[237] William Styron approached history in works such as The Confessions of Nat Turner and Sophie's Choice.[238] Tom Wolfe has occasionally dealt with his southern heritage in bestsellers like I Am Charlotte Simmons.[239] Mount Vernon native Matt Bondurant received critical acclaim for his historic novel The Wettest County in the World about moonshiners in Franklin County during prohibition.[240] Virginia also names a state Poet Laureate.[241]
+
+Rich in cultural heritage, Virginia however ranks near the bottom of U.S. states in terms of public spending on the arts, at nearly half of the national average.[242] The state government does fund some institutions, including the Virginia Museum of Fine Arts and the Science Museum of Virginia. Other museums include the popular Steven F. Udvar-Hazy Center of the National Air and Space Museum and the Chrysler Museum of Art.[243] Besides these sites, many open-air museums are located in the Commonwealth, such as Colonial Williamsburg, the Frontier Culture Museum, and various historic battlefields.[244] The Virginia Foundation for the Humanities works to improve the Commonwealth's civic, cultural, and intellectual life.[245]
+
+Theaters and venues in the Commonwealth are found both in the cities and in suburbs. The Harrison Opera House, in Norfolk, is home of the Virginia Opera. The Virginia Symphony Orchestra operates in and around Hampton Roads.[246] Resident and touring theater troupes operate from the American Shakespeare Center in Staunton.[247] The Barter Theatre in Abingdon, designated the State Theatre of Virginia, won the first Regional Theatre Tony Award in 1948, while the Signature Theatre in Arlington won it in 2009. There is also a Children's Theater of Virginia, Theatre IV, which is the second largest touring troupe nationwide.[248] Notable music performance venues include The Birchmere, the Landmark Theater, and Jiffy Lube Live.[249] Wolf Trap National Park for the Performing Arts is located in Vienna and is the only national park intended for use as a performing arts center.[250]
+
+Virginia has launched many award-winning traditional musical artists and internationally successful popular music acts, as well as Hollywood actors.[1] Virginia is known for its tradition in the music genres of old-time string and bluegrass, with groups such as the Carter Family and Stanley Brothers.[251] The state's African tradition is found through gospel, blues, and shout bands, with both Ella Fitzgerald and Pearl Bailey coming from Newport News.[252] Contemporary Virginia is also known for folk rock artists like Dave Matthews and Jason Mraz, hip hop stars like Pharrell Williams, Missy Elliott and Pusha T, as well as thrash metal groups like GWAR and Lamb of God.[253] Several members of country music band Old Dominion grew up in the Roanoke area, and took their band name from Virginia's state nickname.[254]
+
+Many counties and localities host county fairs and festivals. The Virginia State Fair is held at the Meadow Event Park every September. Also in September is the Neptune Festival in Virginia Beach, which celebrates the city, the waterfront, and regional artists. Norfolk's Harborfest, in June, features boat racing and air shows.[255] Fairfax County also sponsors Celebrate Fairfax! with popular and traditional music performances.[256] The Virginia Lake Festival is held during the third weekend in July in Clarksville.[257] Wolf Trap hosts the Wolf Trap Opera Company, which produces an opera festival every summer.[250] Each September, Bay Days celebrates the Chesapeake Bay as well as Hampton's 400-year history since 1610, and Isle of Wight County holds a County Fair on the second week of September as well. Both feature live music performances, and other unique events.
+
+On the Eastern Shore island of Chincoteague the annual Pony Swim & Auction of feral Chincoteague ponies at the end of July is a unique local tradition expanded into a week-long carnival. The Shenandoah Apple Blossom Festival is a six-day festival held annually in Winchester which includes parades and bluegrass concerts. The Old Time Fiddlers' Convention in Galax, begun in 1935, is one of the oldest and largest such events worldwide. Two important film festivals, the Virginia Film Festival and the VCU French Film Festival, are held annually in Charlottesville and Richmond, respectively.[258]
+
+The Hampton Roads area is the 42nd-largest media market in the United States as ranked by Nielsen Media Research, while the Richmond-Petersburg area is 54th and Roanoke-Lynchburg is 69th as of 2020[update].[259] Northern Virginia is part of the much larger Washington, D.C. media market.
+
+There are 36 television stations in Virginia, representing each major U.S. network, part of 42 stations which serve Virginia viewers including those broadcasting from neighboring jurisdictions.[260] According the Federal Communications Commission, 595 FCC-licensed FM radio stations broadcast in Virginia, with 239 such AM stations as of 2020[update].[261][262] The nationally available Public Broadcasting Service (PBS) is headquartered in Arlington. Independent PBS affiliates exist throughout Virginia, and the Arlington PBS member station WETA-TV produces programs such as the PBS NewsHour and Washington Week.
+
+The most circulated native newspapers in the Commonwealth are Norfolk's The Virginian-Pilot with around 132,000 subscribers,[263] the Richmond Times-Dispatch with 86,219,[264] and The Roanoke Times as of 2018[update].[265] The paper with nation's most daily readers, USA Today, with 520,000 daily subscriptions, is headquartered in McLean.[266] USA Today is the flagship publication of Gannett, Inc., which merged with GateHouse Media in 2019, and operates over one hundred local newspapers nationwide.[267] In Northern Virginia, The Washington Post is the dominant newspaper and provides local coverage for the region.[268] Politico, which covers national politics, has its offices in Rosslyn.[269]
+
+Virginia's educational system consistently ranks in the top five states on the U.S. Department of Education's National Assessment of Educational Progress, with Virginia students outperforming the average in all subject areas and grade levels tested.[270] The 2019 Quality Counts report ranked Virginia's K–12 education third in the country, with a letter grade of B.[271][272] All school divisions must adhere to educational standards set forth by the Virginia Department of Education, which maintains an assessment and accreditation regime known as the Standards of Learning to ensure accountability.[273]
+
+Public K–12 schools in Virginia are generally operated by the counties and cities, and not by the state. As off the 2018–19 academic year,[update] a total of 1,290,576 students were enrolled in 2,293 local and regional schools in the Commonwealth, including eight charter schools, and an additional 98 alternative and special education centers across 133 school divisions.[274][275] 2018 marked the first decline in overall enrollment in public schools, by just over 2,000 students, since 1984.[276] Besides the general public schools in Virginia, there are Governor's Schools and selective magnet schools. The Governor's Schools are a collection of more than 40 regional high schools and summer programs intended for gifted students.[277] The Virginia Council for Private Education oversees the regulation of 483 state accredited private schools.[278] An additional 17,283 students receive homeschooling.[279]
+
+In 2019, 91.5 percent of high school students graduated on-time after four years,[280] an increase of two percent from 2013,[281] and 89.3 percent of adults over the age 25 had their high school diploma.[6] Virginia has one of the smaller racial gaps in graduation rates among U.S. states,[282] with 89.7 percent of Black students graduating on time, compared to 94.7 percent  of white students and 97.5 percent of Asian students.[280] Despite ending school segregation in the 1960s, seven percent of Virginia's public schools were rated as "intensely segregated" by The Civil Rights Project at UCLA in 2019, and the number has risen since 1989, when only three percent were.[283] Virginia has comparatively large public school districts, typically comprising entire counties or cites, and this helps mitigate funding gaps seen in other states such that non-white districts average slightly more funding, $255 per student as of 2019[update], than majority white districts.[284]
+
+As of 2019[update], Virginia has the sixth highest percent of residents with bachelors degrees or higher, with 38.2 percent.[6] As of that year, there are 169 colleges and universities in Virginia.[286] In the 2019 U.S. News & World Report ranking of national public universities, the University of Virginia is ranked No. 3, the College of William and Mary is No. 10, Virginia Tech is No. 30, George Mason University is No. 67, and Virginia Commonwealth University is No. 80.[287] James Madison University is ranked the No. 6 regional university in The South.[288] There are 124 private institutions in the state, including nationally ranked liberal arts colleges Washington and Lee University at No. 11, the University of Richmond at No. 25, and the Virginia Military Institute at No. 81.[286][289]
+
+Virginia Tech and Virginia State University are the state's land-grant universities. The Virginia Military Institute is the oldest state military college.[290] Virginia also operates 23 community colleges on 40 campuses which enrolled more than 228,000 degree-seeking students during the 2018–2019 school year.[291] As of 2019[update], George Mason University had the largest on-campus enrollment at 37,677 students,[292] though the private Liberty University had the largest total enrollment in the state, with 88,283 online and 15,105 on-campus students in Lynchburg.[293]
+
+Virginia has a mixed health record, and was ranked as the 15th overall healthiest state according to the 2019 United Health Foundation's Health Rankings. Virginia was 19th lowest among U.S. states in its number of premature deaths, with 6,914 per 100,000, and 24th with an infant mortality rate of 5.9 per 1,000 live births.[42] There are however racial and social health disparities. With high rates of heart disease and diabetes, African Americans in Virginia had an average life expectancy 4 years lower than whites and 12 years lower than Asian Americans and Latinos in 2017,[296] and were disproportionately affected by COVID-19 during the coronavirus pandemic.[297] African-American mothers are also three times more likely to die while giving birth in the state.[298] Mortality rates among white middle-class Virginians have also been rising, with drug overdose, suicide, and alcohol poisoning as leading causes.[299]
+
+Weight is an issue for many Virginians, and 30.3% of adults and 13.2% of 10- to 17-year-olds are obese as of 2019[update].[42][300] Additionally, 35% of adults are overweight and 23.3% do not exercise regularly.[301] Virginia banned smoking in bars and restaurants in January 2010,[302] and the percent of tobacco smokers in the state has declined from 19% in that year to 14.9% in 2019. Virginia does have among the highest rates of immunization nationwide, ranking 6th for childhood immunization and 14th for both TDaP and HPV vaccines per capita.[42] Virginia was the first U.S. state to mandate HPV vaccination for girls for school attendance, which it did in 2008.[303]
+
+There are 90 hospitals in Virginia with a combined 17,706 hospital beds as of 2020[update].[304] Notable examples include Inova Fairfax Hospital, the largest hospital in the Washington Metropolitan Area, and the VCU Medical Center, located on the medical campus of Virginia Commonwealth University. The University of Virginia Medical Center, part of the University of Virginia Health System, is highly ranked in endocrinology according to U.S. News & World Report.[305] Virginia has a ratio of 148.1 primary care physicians per 10,000 residents, which is the 24th highest nationally, but only 171.9 mental health providers per that number, the 10th lowest nationwide. The rate of uninsured Virginians dropped to 8.8% after the state government passed Medicare expansion in 2019.[42]
+
+Because of the 1932 Byrd Road Act, the state government controls most of Virginia's roads, instead of a local county authority as is usual in other states.[307] As of 2018[update], the Virginia Department of Transportation owns and operates 57,867 miles (93,128 km) of the total 70,105 miles (112,823 km) of roads in the state, making it the third largest state highway system in the United States.[308] Although the Washington Metropolitan Area, which includes Northern Virginia, has the second highest rate of traffic congestion in the nation, Virginia as a whole has the 21st-lowest rate of congestion and the average commute time is 26.9 minutes.[309][310] Virginia hit peak car usage before the year 2000, making it one of the first such states.[311]
+
+Virginia has Amtrak passenger rail service along several corridors, and Virginia Railway Express (VRE) maintains two commuter lines into Washington, D.C. from Fredericksburg and Manassas. VRE is one of the nation's fastest growing commuter rail services, handling nearly 20,000 passengers a day.[312] Arlington accounted for forty percent of Virginia's public transit trips as of 2013[update], with most of that being from the Washington Metro transit system, which also serves Alexandria and communities in Fairfax County along I-66.[313] The system is currently expanding west into additional areas of Loudoun County.[314] Major freight railroads in Virginia include Norfolk Southern and CSX Transportation. Commuter buses include the Fairfax Connector, FRED buses in Fredericksburg, and OmniRide in Prince William County.[315] The Virginia Department of Transportation operates several free ferries throughout Virginia, the most notable being the Jamestown Ferry which connects Jamestown to Scotland Wharf across the James River.[316]
+
+Virginia has five major airports: Washington Dulles International and Reagan Washington National in Northern Virginia, both of which handle more than twenty million passengers a year; Richmond International; and Newport News/Williamsburg International Airport and Norfolk International serving the Hampton Roads area. Several other airports offer limited commercial passenger service, and sixty-six public airports serve the state's aviation needs.[317] The Virginia Port Authority's main seaports are those in Hampton Roads, which carried 69,416,600 short tons (62,973,700 t) of total cargo in 2018[update], the fifth most of United States ports.[318] The Eastern Shore of Virginia is the site of Wallops Flight Facility, a rocket testing center owned by NASA, and the Mid-Atlantic Regional Spaceport, a commercial spaceport.[319][320] Space tourism is also offered through Vienna-based Space Adventures.[321]
+
+In 1619, the first Virginia General Assembly met at Jamestown Church, and included 22 locally elected representatives, making Virginia's legislature the oldest in the North America.[8] These representatives became a formal House of Burgesses in 1642 and governed with the crown-appointed Governor's Council until Virginia declared independence in 1776. The current General Assembly is the 161st since that year. The government today functions under the seventh Constitution of Virginia, which was approved by voters in 1971 and is similar to the federal structure in that it provides for three branches: a strong legislature, an executive, and a unified judicial system.[322]
+
+Virginia's legislature is bicameral with a 100-member House of Delegates and 40-member Senate, who together write the laws for the Commonwealth. Delegates serve two-year terms, while senators serve four-year terms, with the most recent elections for both taking place in November 2019. The legislature meets annually starting on the second Wednesday of the year, typically for 60 days in even years and 48 days in odd years due to the state's biannual budgeting, though special sessions can be called either by the governor or with agreement of two-thirds of both houses.[323] Special sessions are common, and have been called in 2019 and 2020 for topics such as gun control, the impact of the coronavirus on the state budget, and police reform.[324][325]
+
+The executive department includes the governor and lieutenant governor, who are elected every four years in separate elections, with the next taking place in November 2021. The governor must be at least 30 years old and incumbent governors cannot run for re-election, however the lieutenant governor and attorney general can, and governors can and have served non-consecutive terms.[322] The lieutenant governor is the official head of the Senate, and is responsible for breaking ties. The House elects a Speaker of the House and the Senate elects a President pro tempore, who presides when the lieutenant governor isn't present, and both houses elect a clerk and majority and minority leaders.[323] State budgets are proposed in even years by the governor.[326] Based on data through 2018, the Pew Center on the States found the state government to be above average in running surpluses,[327] while U.S. News and World Report ranked the state eighth in fiscal stability.[328]
+
+The judges and justices who make up Virginia's judicial system, also the oldest in America, are elected by a majority vote in both the House and Senate without input from the governor, one way Virginia's legislature is stronger than its executive. The system consists of a hierarchy from the Supreme Court of Virginia and the Court of Appeals of Virginia to the Circuit Courts, the trial courts of general jurisdiction, and the lower General District Courts and Juvenile and Domestic Relations District Courts.[329] The Supreme Court has seven justices who serve twelve-year terms, with a mandatory retirement age of 73. The Supreme Court selects its own Chief Justice from among their seven members, who is informally limited to two four-year terms.[330]
+
+The Code of Virginia is the statutory law, and consists of the codified legislation of the General Assembly. The Virginia State Police is the largest law enforcement agency in Virginia. The Virginia Capitol Police is the oldest police department in the United States.[331] The Virginia National Guard consists of 7,500 soldiers in the Virginia Army National Guard and 1,200 airmen in the Virginia Air National Guard.[332] Since the resumption of capital punishment in Virginia in 1982, 113 people have been executed, the second highest number in the nation, and three inmates are on the state's death row as of 2019[update].[333] Virginia has the fourth lowest violent crime rate and 13th-lowest property crime rate as of 2018[update] according to FBI data.[334] Since Virginia ended prisoner parole in 1995, the rate of recidivism has fallen to 23.4 percent in 2019, the lowest nationwide.[335]
+
+Over the 20th century, Virginia shifted from a largely rural, politically Southern and conservative state to a more urbanized, pluralistic, and politically moderate environment. Up until the 1970s, Virginia was a racially divided one-party state dominated by the Byrd Organization,[337] which sought to stymie the political power of Northern Virginia, perpetuate segregation, and restrict voter registration.[338] The organization used  malapportionment to control what areas of the state were over-represented in the General Assembly and the U.S. Congress until ordered to end the practice by the 1964 U.S. Supreme Court decision in Davis v. Mann and the 1965 the Virginia Supreme Court decision in Wilkins v. Davis respectively.[339]
+
+Passage of Federal civil rights legislation in the mid-1960s, including the Voting Rights Act of 1965, helped end the state's Jim Crow laws which effectively disfranchised African Americans.[340] Greater enfranchisement and demographic shifts further changed the electorate. In 1980, 56 percent of eligible voters were born in the state; in 2019 that number was 45 percent, a result of strong international immigration and domestic migration into the state.[341]
+
+Regional differences also play a large part in Virginia politics.[342] While urban and growing suburban areas, including much of Northern Virginia, form the Democratic Party base, rural southern and western areas moved to support the Republican Party in response to its "southern strategy".[343][344] Rural Democratic support has nevertheless persisted in union-influenced Roanoke in Southwest Virginia, college towns such as Charlottesville and Blacksburg, and the southeastern Black Belt Region.[345] State election seasons traditionally start with the annual Shad Planking event in Wakefield.[336]
+
+State elections in Virginia occur in odd-numbered years, with executive department elections occurring in years following U.S. presidential elections and Senate elections occurring in the years prior to presidential elections, as both have four-year terms. House of Delegates elections take place concurrent with each of those elections as members have two-year terms. National politics often play a role in state election outcomes, and Virginia has elected governors of the party opposite the U.S. president in ten of the last eleven contests, with only Terry McAuliffe beating the trend.[346][347]
+
+McAuliffe, a Democrat, was elected Governor in the 2013 elections by two percentage points during Barack Obama's second presidential term.[348] Republicans, however, held a super-majority (68–32) of seats in the House of Delegates, which they had first gained in the 2011 state elections.[349] Republicans also held a one-vote majority the state senate, which they then maintained in the 2015 election.[350] Eleven house district lines used in these elections, drawn following the 2010 U.S. Census, were later judged unconstitutional for discriminating against African Americans.[351]
+
+The 2017 statewide elections resulted in Democrats holding the three highest offices, with outgoing lieutenant governor Ralph Northam winning the governorship, Justin Fairfax elected lieutenant governor, and Mark Herring continuing as attorney general. In concurrent House of Delegates elections, Democrats flipped fifteen of the Republicans' previous sixteen-seat majority.[352] Control of the House came down to the tied election in the 94th district, which was won by Republicans through drawing of lots, giving the party a slim 51–49 majority in the 2018–19 legislative sessions.[353] Despite a political crisis that February, Democrats took full control of the General Assembly in the November 2019 elections,[354] the first after several districts were redrawn because of discrimination.[355]
+
+In federal elections since 2006, both parties have seen successes. Republican Senator George Allen lost close races in 2006, to Democratic newcomer Jim Webb, and again in 2012, to Webb's replacement, former Governor Tim Kaine.[356] In 2008, Democrats won both United States Senate seats; former Governor Mark Warner was elected to replace retiring Republican John Warner.[357] In the 2010 mid-term elections, the first under President Obama, Republicans flipped three United States House of Representatives seats from the Democrats, while in the 2018 mid-terms, the first under President Trump, Democrats flipped three seats from Republicans. Of the state's eleven seats in the House of Representatives, Democrats currently hold seven and Republicans hold four.
+
+Though Virginia was considered a "swing state" in recent presidential elections,[7] Democrat Barack Obama carried Virginia's 13 electoral votes in 2008 and 2012,[358] while Democrat Hillary Clinton carried the state in 2016. Virginia had previously voted for Republican presidential candidates in 13 out of 14 presidential elections from 1952 to 2004, including 10 in a row from 1968 to 2004.[7] Virginia currently holds its presidential primary election on Super Tuesday, the same day as thirteen other states, with the most recent held on March 3, 2020.[359]
+
+Virginia is the most populous U.S. state without a major professional sports league franchise.[360] The reasons for this include the lack of any dominant city or market within the state, the proximity of teams in Washington, D.C. and North Carolina, and a reluctance to publicly finance stadiums.[361][362] A proposed arena in Virginia Beach designed for an NBA franchise became the latest unsuccessful sports initiative when the city council there ended support in 2017.[363] Norfolk is however host to two minor league teams: The AAA Norfolk Tides and the ECHL's Norfolk Admirals. The San Francisco Giants' AA team, the Richmond Flying Squirrels, began play at The Diamond in 2010, replacing the AAA Richmond Braves, who relocated after 2008.[364] Additionally, the Washington Nationals, Boston Red Sox, Cleveland Indians, Atlanta Braves, Pittsburgh Pirates, New York Yankees, and Toronto Blue Jays also have Single-A and Rookie-level farm teams in Virginia.[365] The Richmond Kickers, a United Soccer League club, have operated since 1993 and are the only team in their league to win both the league championship and the U.S. Open Cup in the same year.[366]
+
+The Washington Football Team have their headquarters in Ashburn and their training facility is in Richmond,[367] and the Washington Capitals train at MedStar Capitals Iceplex in Ballston. Virginia has many professional caliber golf courses including the Greg Norman course at Lansdowne Resort and Kingsmill Resort, home of the Kingsmill Championship, an LPGA Tour tournament. NASCAR currently schedules Monster Energy NASCAR Cup races on two tracks in Virginia: Martinsville Speedway and Richmond Raceway. Virginia natives currently competing in the series include Denny Hamlin and Elliott Sadler.[368]
+
+Virginia does not allow state appropriated funds to be used for either operational or capital expenses for intercollegiate athletics.[370] Despite this, both the Virginia Cavaliers and Virginia Tech Hokies have been able to field competitive teams in the Atlantic Coast Conference and maintain modern facilities. Their rivalry is followed statewide. Twelve other universities compete in NCAA Division I, particularly in the Atlantic 10 Conference, Big South Conference, and Colonial Athletic Association. Three historically Black schools compete in the Division II Central Intercollegiate Athletic Association, and two others (Hampton and Norfolk State) compete in Division I. Several smaller schools compete in the Old Dominion Athletic Conference and the USA South Athletic Conference of NCAA Division III. The NCAA currently holds its Division III championships in football, men's basketball, volleyball and softball in Salem.[371]
+
+The state nickname is its oldest symbol, though it has never been made official by law. Virginia was given the title "Dominion" by King Charles II of England at the time of The Restoration, because it had remained loyal to the crown during the English Civil War, and the present moniker, "Old Dominion" is a reference to that title. Charles' supporters were called Cavaliers, and "The Cavalier State" nickname was popularized after the American Civil War to romanticize the antebellum period. Sports teams from the University of Virginia are called the Cavaliers.[372] The other nickname, "Mother of Presidents", is also historic, as eight Virginians have served as President of the United States, including four of the first five.[1]
+
+The state's motto, Sic Semper Tyrannis, translates from Latin as "Thus Always to Tyrants", and is used on the state seal, which is then used on the flag. While the seal was designed in 1776, and the flag was first used in the 1830s, both were made official in 1930.[373] The majority of the other symbols were made official in the late 20th century.[374] The Virginia reel is among the square dances classified as the state dance.[375] In 1940, Virginia made "Carry Me Back to Old Virginny" the state song, but it was retired in 1997 due to its references to slavery. In March 2015, Virginia named "Our Great Virginia", which uses the tune of "Oh Shenandoah", as the traditional state song and "Sweet Virginia Breeze" as the popular state song.[376]

en/6004.html.txt

@@ -0,0 +1,201 @@
+Coordinates: 38°N 79°W / 38°N 79°W / 38; -79
+
+Virginia (/vərˈdʒɪniə/ (listen)), officially the Commonwealth of Virginia, is a state in the Southeastern[4] and Mid-Atlantic[5] regions of the United States located between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth are shaped by the Blue Ridge Mountains and the Chesapeake Bay, which provide habitat for much of its flora and fauna. The capital of the Commonwealth is Richmond; Virginia Beach is the most populous city, and Fairfax County is the most populous political subdivision. The Commonwealth's estimated population as of 2019[update] is over 8.54 million.[6]
+
+The area's history begins with several indigenous groups, including the Powhatan. In 1607 the London Company established the Colony of Virginia as the first permanent English colony in the New World. Virginia's state nickname, the Old Dominion, is a reference to this status. Slave labor and the land acquired from displaced Native American tribes each played a significant role in the colony's early politics and plantation economy. Virginia was one of the 13 Colonies in the American Revolution. In the American Civil War, Virginia's Secession Convention resolved to join the Confederacy while the First Wheeling Convention resolved to remain in the Union, leading to a split that created West Virginia. Although the Commonwealth was under one-party rule for nearly a century following Reconstruction, both major national parties are competitive in modern Virginia.[7]
+
+Virginia's state legislature is the Virginia General Assembly, which was established in 1619 and is the oldest continuous law-making body in North America. It is made up of a 40-member Senate and a 100-member House of Delegates.[8] The state government is unique in how it treats cities and counties equally, manages local roads, and prohibits governors from serving consecutive terms. Virginia's economy has many sectors: agriculture in the Shenandoah Valley; federal agencies in Northern Virginia, including the headquarters of the U.S. Department of Defense and Central Intelligence Agency; and military facilities in Hampton Roads, the site of the region's main seaport.
+
+Virginia has a total area of 42,774.2 square miles (110,784.7 km2), including 3,180.13 square miles (8,236.5 km2) of water, making it the 35th-largest state by area.[9] Virginia is bordered by Maryland and Washington, D.C. to the north and east; by the Atlantic Ocean to the east; by North Carolina to the south; by Tennessee to the southwest; by Kentucky to the west; and by West Virginia to the north and west. Virginia's boundary with Maryland and Washington, D.C. extends to the low-water mark of the south shore of the Potomac River.[10]
+
+The state's southern border is defined as 36°30' north latitude, though surveyor error in the 1700s led to deviations of as much as three arcminutes.[11] From 1802 to 1803, a commission appointed by Virginia and Tennessee surveyed the area and set their border as a line from the summit of White Top Mountain to the top of the Cumberland Mountains. Errors discovered in 1856 led Virginia to propose a new surveying commission in 1871, but in 1893 the U.S. Supreme Court decided in favor of the 1803 line in the case Virginia v. Tennessee.[12][13] One result of this is the division of the city of Bristol between the two states.[14]
+
+The Chesapeake Bay separates the contiguous portion of the Commonwealth from the two-county peninsula of Virginia's Eastern Shore. The bay was formed from the drowned river valleys of the Susquehanna River and the James River.[15] Many of Virginia's rivers flow into the Chesapeake Bay, including the Potomac, Rappahannock, York, and James, which create three peninsulas in the bay.[16] Sea level rise has eroded the land on Virginia's islands, which include Tangier Island in the bay and Chincoteague, one of 23 barrier islands on the Atlantic coast.[17][18]
+
+The Tidewater is a coastal plain between the Atlantic coast and the fall line. It includes the Eastern Shore and major estuaries of Chesapeake Bay. The Piedmont is a series of sedimentary and igneous rock-based foothills east of the mountains which were formed in the Mesozoic era.[20] The region, known for its heavy clay soil, includes the Southwest Mountains around Charlottesville.[21] The Blue Ridge Mountains are a physiographic province of the Appalachian Mountains with the highest points in the commonwealth, the tallest being Mount Rogers at 5,729 feet (1,746 m).[2] The Ridge and Valley region is west of the mountains and includes the Great Appalachian Valley. The region is carbonate rock based and includes Massanutten Mountain.[22] The Cumberland Plateau and the Cumberland Mountains are in the southwest corner of Virginia, south of the Allegheny Plateau. In this region, rivers flow northwest, with a dendritic drainage system, into the Ohio River basin.[23]
+
+The Virginia Seismic Zone has not had a history of regular earthquake activity. Earthquakes are rarely above 4.5 in magnitude, because Virginia is located away from the edges of the North American Plate. A 5.8 magnitude earthquake struck central Virginia on August 23, 2011, near Mineral, and was the state's largest in at least a century.[24] Due to the area's geologic properties, the earthquake was felt from Northern Florida to Southern Ontario.[25] 35 million years ago, a bolide impacted what is now eastern Virginia. The resulting Chesapeake Bay impact crater may explain what earthquakes and subsidence the region does experience.[26]
+
+Coal mining takes place in the three mountainous regions at 45 distinct coal beds near Mesozoic basins.[27] More than 64 million tons of other non-fuel resources, such as slate, kyanite, sand, or gravel, were also mined in Virginia in 2018[update].[28] The commonwealth's carbonate rock is filled with more than 4,000 caves, ten of which are open for tourism, including the popular Luray Caverns and Skyline Caverns.[29]
+
+Virginia has a humid subtropical climate that transitions to humid continental west of the Blue Ridge Mountains.[30] Seasonal extremes vary from average lows of 25 °F (−4 °C) in January to average highs of 86 °F (30 °C) in July.[31] The Atlantic Ocean and Gulf Stream have a strong effect on eastern and southeastern coastal areas of the commonwealth, making the climate there warmer and more constant. Most of Virginia's recorded extremes in temperature and precipitation have occurred in the Blue Ridge Mountains and areas west.[32] Virginia receives an average of 43.34 inches (110 cm) of precipitation annually,[31] with the Shenandoah Valley being the state's driest region due to the mountains on either side.[32]
+
+Virginia has around 35–45 days with thunderstorms annually, and storms are common in the late afternoon and evenings between April and September.[33] These months are also the most common for tornadoes, 19 of which touched down in the state in 2019.[34] Hurricanes and tropical storms can occur from August to October, and though they typically impact coastal regions, the deadliest natural disaster in Virginia was Hurricane Camille, which killed over 150 people in 1969, mainly inland in Nelson County.[32][35] Between December and March, cold-air damming caused by the Appalachian Mountains can lead to significant snowfalls across the state, such as the January 2016 blizzard, which created the state's highest recorded snowfall of 36.6 inches (93 cm) near Bluemont.[36][37] Virginia only received 13.1 inches (33 cm) of snow during winter 2018–19, just above the state's average of 10 inches (25 cm).[38]
+
+Climate change in Virginia is leading to higher temperatures year-round as well as more heavy rain and flooding events.[39] Urban heat islands can be found in many Virginia cities and suburbs, particularly in neighborhoods linked to historic redlining.[40] Arlington had the most code orange days in 2019 for high ozone pollution in the air, with 12, followed by Fairfax County with 7.[41] Exposure of particulate matter in Virginia's air has decreased 49% from 13.5 micrograms per cubic meter in 2003 to 6.9 in 2019.[42] The closure and conversion of coal power plants in Virginia and the Ohio Valley region has reduced haze in the mountains, which peaked in 1998.[43] Virginia's 6 coal power plants must shut down by 2025,[44] and current plans call for 30 percent of the state's electricity to be renewable by 2030 and for all of it to be carbon-free by 2050.[45]
+
+Forests cover 62 percent of Virginia as of 2019[update], of which 78 percent is considered hardwood forest, meaning that trees in Virginia are primarily deciduous and broad-leaved. The other 22 percent is pine, with Loblolly and shortleaf pine dominating much of central and eastern Virginia.[46] In the western and mountainous parts of the commonwealth, oak and hickory are most common, while lower altitudes are more likely to have small but dense stands of moisture-loving hemlocks and mosses in abundance.[32] Gypsy moth infestations in oak trees and the blight in chestnut trees have decreased both of their numbers, leaving more room for hickory and invasive ailanthus trees.[47][32] In the lowland tidewater and Piedmont, yellow pines tend to dominate, with bald cypress wetland forests in the Great Dismal and Nottoway swamps.[46] Other common trees and plants include red bay, wax myrtle, dwarf palmetto, tulip poplar, mountain laurel, milkweed, daisies, and many species of ferns. The largest areas of wilderness are along the Atlantic coast and in the western mountains, where the largest populations of trillium wildflowers in North America are found.[32][48]
+
+Virginia is home to more than one million white-tailed deer, whose population have rebounded from an estimated 25,000 to 50,000 during the Great Depression.[49] Native carnivorans include black bears, bobcats, coyotes, both gray and red foxes, raccoons, and skunks. Rodents include groundhogs, weasels, nutria, beavers, both gray squirrels and fox squirrels, chipmunks, and Allegheny woodrats, while bats include brown bats and the Virginia big-eared bat, the state mammal.[50] The Virginia opossum is also the only marsupial native to the United States and Canada,[51] and the native Appalachian cottontail was recognized as a distinct species of rabbit in 1992.[52]
+
+Virginia's bird fauna, as of 1995, consists of some 422 species, of which 359 are regularly occurring, 41 are accidental (vagrant), 20 are hypothetical, and two are extinct; of the regularly occurring species, 214 have bred in Virginia, while the rest are winter residents or transients in Virginia.[53] There are no species of bird endemic to the state.[53] Audubon recognizes 21 Important Bird Areas in the Virginia.[54] Peregrine falcons, whose numbers dramatically declined due to DDT pesticide poisoning in the middle of the 20th century, are the focus of conservation efforts in the state; as of 2017, Virginia had 31 breeding pairs of the bird, and a reintroduction program in Shenandoah National Park was underway.[55]
+
+Virginia has 226 species of freshwater fish, from 25 families; the state's diverse array of fish species is attributable to its varied and humid climate, physiography, river system interconnections, and lack of Pleistocene glaciers. For example, the state is home to Eastern blacknose dace and sculpin (on the Appalachian Plateau); smallmouth bass and redhorse sucker (in the Ridge and Valley region); brook trout, rainbow trout, brown trout, and the Kanawha darter (in the Blue Ridge); stripeback darter and Roanoke Bass (in the Piedmont); and swampfish, bluespotted sunfish, and pirate perch (on the Coastal Plain).[56] The Chesapeake Bay is host to many species, including blue crabs, clams, oysters, rockfish, as well as the invasive blue catfish.[57] Running brooks with rocky bottoms are often inhabited by plentiful amounts of crayfish.[32] Amphibians found in Virginia include the Cumberland Plateau salamander and Eastern hellbender.[58]
+
+Virginia has 30 National Park Service units, such as Great Falls Park and the Appalachian Trail, and one national park, Shenandoah National Park.[59] Shenandoah was established in 1935 and encompasses the scenic Skyline Drive. Almost forty percent (79,579 acres or 322.04 km2) of the park's total 199,173 acres (806.02 km2) area has been designated as wilderness under the National Wilderness Preservation System.[60] Virginia also has 38 Virginia state parks, 3 undeveloped parks, and 63 natural areas, totaling 127,000 acres (51,000 ha), of which approximately 70,000 acres (28,000 ha) are in state parks.[61] All are managed by the Virginia Department of Conservation and Recreation except for Breaks Interstate Park.[62] which lies on the Virginia-Kentucky border and is one of only two inter-state parks in the United States.[63] There are 22 state forests and other state lands managed by the Virginia Department of Forestry, totaling 67,920 acres (27,490 ha).[64] The Chesapeake Bay is not a national park, but is protected by both state and federal legislation; the jointly run Chesapeake Bay Program which conducts restoration on the bay and its watershed. The Great Dismal Swamp National Wildlife Refuge extends into North Carolina, as does the Back Bay National Wildlife Refuge, which marks the beginning of the Outer Banks.[65]
+
+Virginia celebrated its quadricentennial year in 2007, marking 400 years since the establishment of the Jamestown Colony. The observances highlighted contributions from Native Americans, Africans, and Europeans, each of which had a significant part in shaping Virginia's history.[67][68] Warfare, including among these groups, has also had an important role. Virginia was a focal point in conflicts from the French and Indian War, the American Revolution and the Civil War, to the Cold War and the War on Terrorism.[69] Fictionalized stories about the early colony, in particular the story of Pocahontas and John Smith, first became popular in the period after the Revolutionary War, and together with other myths surrounding George Washington's childhood and plantation elite in the antebellum period became touchstones of Virginian and American culture and helped shape the state's historic politics and beliefs.[70][66]
+
+The first people are estimated to have arrived in Virginia over 12,000 years ago.[71] By 5,000 years ago more permanent settlements emerged, and farming began by 900 AD. By 1500, the Algonquian peoples had founded towns such as Werowocomoco in the Tidewater region, which they referred to as Tsenacommacah. The other major language groups in the area were the Siouan to the west, and the Iroquoians, who included the Nottoway and Meherrin, to the north and south. After 1570, the Algonquians consolidated under Chief Powhatan in response to threats from these other groups on their trade network.[72] Powhatan controlled more than 30 smaller tribes and more than 150 settlements, who shared a common Virginia Algonquian language. In 1607, the native Tidewater population was between 13,000 and 14,000.[73]
+
+Several European expeditions, including a group of Spanish Jesuits, explored the Chesapeake Bay during the 16th century.[74] In 1583, Queen Elizabeth I of England granted Walter Raleigh a charter to plant a colony north of Spanish Florida.[75] In 1584, Raleigh sent an expedition to the Atlantic coast of North America.[76] The name "Virginia" may have been suggested then by Raleigh or Elizabeth, perhaps noting her status as the "Virgin Queen", and may also be related to a native phrase, "Wingandacoa", or name, "Wingina".[77] Initially the name applied to the entire coastal region from South Carolina to Maine, plus the island of Bermuda.[78] The London Company was incorporated as a joint stock company by the proprietary Charter of 1606, which granted land rights to this area. The company financed the first permanent English settlement in the "New World", Jamestown. Named for King James I, it was founded in May 1607 by Christopher Newport.[79] In 1619, colonists took greater control with an elected legislature called the House of Burgesses. With the bankruptcy of the London Company in 1624, the settlement was taken into royal authority as an English crown colony.[80]
+
+Life in the colony was perilous, and many died during the Starving Time in 1609 and the Anglo-Powhatan Wars, including the Indian massacre of 1622, which fostered the colonists' negative view of all tribes.[81] By 1624, only 3,400 of the 6,000 early settlers had survived.[82] However, European demand for tobacco fueled the arrival of more settlers and servants.[83] The headright system tried to solve the labor shortage by providing colonists with land for each indentured servant they transported to Virginia.[84] African workers were first imported to Jamestown in 1619 initially under the rules of indentured servitude. The shift to a system of African slavery in Virginia was propelled by the legal cases of John Punch, who was sentenced to lifetime slavery in 1640 for attempting to escape his servitude, and of John Casor, who was claimed by Anthony Johnson as his servant for life in 1655.[85] Slavery first appears in Virginia statutes in 1661 and 1662, when a law made it hereditary based on the mother's status.[86]
+
+Tensions and the geographic differences between the working and ruling classes led to Bacon's Rebellion in 1676, by which time current and former indentured servants made up as much as eighty percent of the population.[87] Rebels, largely from the colony's frontier, were also opposed to the conciliatory policy towards native tribes, and one result of the rebellion was the signing at Middle Plantation of the Treaty of 1677, which made the signatory tribes tributary states and was part of a pattern of appropriating tribal land by force and treaty. Middle Plantation saw the founding of The College of William & Mary in 1693 and was renamed Williamsburg as it became the colonial capital in 1699.[88] In 1747, a group of Virginian speculators formed the Ohio Company, with the backing of the British crown, to start English settlement and trade in the Ohio Country west of the Appalachian Mountains.[89] France, which claimed this area as part of their colony of New France, viewed this as a threat, and the ensuing French and Indian War became part of the Seven Years' War (1756–1763). A militia from several British colonies, called the Virginia Regiment, was led by then-Lieutenant Colonel George Washington.[90]
+
+The British Parliament's efforts to levy new taxes following the French and Indian War were deeply unpopular in the colonies. In the House of Burgesses, opposition to taxation without representation was led by Patrick Henry and Richard Henry Lee, among others.[91] Virginians began to coordinate their actions with other colonies in 1773, and sent delegates to the Continental Congress the following year.[92] After the House of Burgesses was dissolved by the royal governor in 1774, Virginia's revolutionary leaders continued to govern via the Virginia Conventions. On May 15, 1776, the Convention declared Virginia's independence from the British Empire and adopted George Mason's Virginia Declaration of Rights, which was then included in a new constitution.[93] Another Virginian, Thomas Jefferson, drew upon Mason's work in drafting the national Declaration of Independence.[94]
+
+When the American Revolutionary War began, George Washington was selected to head the colonial army. During the war, the capital was moved to Richmond at the urging of Governor Thomas Jefferson, who feared that Williamsburg's coastal location would make it vulnerable to British attack.[95] In 1781, the combined action of Continental and French land and naval forces trapped the British army on the Virginia Peninsula, where troops under George Washington and Comte de Rochambeau defeated British General Cornwallis in the Siege of Yorktown. His surrender on October 19, 1781 led to peace negotiations in Paris and secured the independence of the colonies.[96]
+
+Virginians were instrumental in writing the United States Constitution. James Madison drafted the Virginia Plan in 1787 and the Bill of Rights in 1789.[94] Virginia ratified the Constitution on June 25, 1788. The three-fifths compromise ensured that Virginia, with its large number of slaves, initially had the largest bloc in the House of Representatives. Together with the Virginia dynasty of presidents, this gave the Commonwealth national importance. In 1790, both Virginia and Maryland ceded territory to form the new District of Columbia, though the Virginian area was retroceded in 1846.[97] Virginia is called the "Mother of States" because of its role in being carved into states such as Kentucky, which became the 15th state in 1792, and for the numbers of American pioneers born in Virginia.[98]
+
+In addition to agriculture, slave labor was increasingly used in mining, shipbuilding and other industries.[99] The execution of Gabriel Prosser in 1800, Nat Turner's slave rebellion in 1831 and John Brown's Raid on Harpers Ferry in 1859 marked the growing social discontent over slavery and its role in the plantation economy. By 1860, almost half a million people, roughly 31 percent of the total population of Virginia, were enslaved.[100] This division contributed to the start of the American Civil War.
+
+Virginia voted to secede from the United States on April 17, 1861, after the Battle of Fort Sumter and Abraham Lincoln's call for volunteers. On April 24, Virginia joined the Confederate States of America, which chose Richmond as its capital.[98] After the 1861 Wheeling Convention, 48 counties in the northwest separated to form a new state of West Virginia, which chose to remain loyal to the Union. Virginian general Robert E. Lee took command of the Army of Northern Virginia in 1862, and led invasions into Union territory, ultimately becoming commander of all Confederate forces. During the war, more battles were fought in Virginia than anywhere else, including Bull Run, the Seven Days Battles, Chancellorsville, and the concluding Battle of Appomattox Court House.[101] After the capture of Richmond in April 1865, the state capital was briefly moved to Lynchburg,[102] while the Confederate leadership fled to Danville.[103] Virginia was formally restored to the United States in 1870, due to the work of the Committee of Nine.[104]
+
+During the post-war Reconstruction era, Virginia adopted a constitution which provided for free public schools, and guaranteed political, civil, and voting rights.[105] The populist Readjuster Party ran an inclusive coalition until the conservative white Democratic Party gained power after 1883.[106] It passed segregationist Jim Crow laws and in 1902 rewrote the Constitution of Virginia to include a poll tax and other voter registration measures that effectively disenfranchised most African Americans and many poor European Americans.[107] Though their schools and public services were segregated and underfunded due to a lack of political representation, African Americans were able to unite in communities and take a greater role in Virginia society.[108]
+
+New economic forces also changed the Commonwealth. Virginian James Albert Bonsack invented the tobacco cigarette rolling machine in 1880 leading to new industrial scale production centered around Richmond. In 1886, railroad magnate Collis Potter Huntington founded Newport News Shipbuilding, which was responsible for building six World War I-era dreadnoughts, seven battleships, and 25 destroyers for the U.S. Navy from 1907 to 1923.[109] During the war, German submarines like U-151 attacked ships outside the port.[110] In 1926, Dr. W.A.R. Goodwin, rector of Williamsburg's Bruton Parish Church, began restoration of colonial-era buildings in the historic district with financial backing of John D. Rockefeller, Jr.[111] Though their project, like others in the state, had to contend with the Great Depression and World War II, work continued as Colonial Williamsburg became a major tourist attraction.[112]
+
+Protests started by Barbara Rose Johns in 1951 in Farmville against segregated schools led to the lawsuit Davis v. County School Board of Prince Edward County. This case, filed by Richmond natives Spottswood Robinson and Oliver Hill, was decided in 1954 with Brown v. Board of Education, which rejected the segregationist doctrine of "separate but equal". But, in 1958, under the policy of "massive resistance" led by the influential segregationist Senator Harry F. Byrd and his Byrd Organization, the Commonwealth prohibited desegregated local schools from receiving state funding.[113]
+
+The civil rights movement gained many participants in the 1960s. It achieved the moral force and support to gain passage of national legislation with the Civil Rights Act of 1964 and the Voting Rights Act of 1965. In 1964 the United States Supreme Court ordered Prince Edward County and others to integrate schools.[114] In 1967, the Court also struck down the state's ban on interracial marriage with Loving v. Virginia. From 1969 to 1971, state legislators under Governor Mills Godwin rewrote the constitution, after goals such as the repeal of Jim Crow laws had been achieved. In 1989, Douglas Wilder became the first African American elected as governor in the United States.[115]
+
+The Cold War led to the expansion of national defense government programs housed in offices in Northern Virginia near Washington, D.C., and correlative population growth.[116] The Central Intelligence Agency in Langley was involved in various Cold War events, including as the target of Soviet espionage activities. Also among the federal developments was the Pentagon, built during World War II as the headquarters for the Department of Defense. It was one of the targets of the September 11 attacks; 189 people died at the site when a jet passenger plane was flown into the building.[117] Mass shootings at Virginia Tech in 2007 and in Virginia Beach in 2019 led to passage of gun control measures in 2020.[118] Racial injustice and the presence of Confederate monuments in Virginia have also led to large demonstrations, including in August 2017, when a white supremacist drove his car into protesters, killing one, and in June 2020, when protests that were part of the larger Black Lives Matter movement brought about the removal of statues on Monument Avenue in Richmond and elsewhere.[119]
+
+Virginia is divided into 95 counties and 38 independent cities, the latter acting in many ways as county-equivalents.[120] This general method of treating cities and counties on par with each other is unique to Virginia; only three other independent cities exist elsewhere in the United States, each in a different state.[121] Virginia limits the authority of cities and counties to countermand laws expressly allowed by the Virginia General Assembly under what is known as Dillon's Rule.[122] In addition to independent cities, there are also incorporated towns which operate under their own governments, but are part of a county. Finally there are hundreds of unincorporated communities within the counties. Virginia does not have any further political subdivisions, such as villages or townships.
+
+Over 3.1 million people, 36 percent of Virginians, live in Northern Virginia, which is part of the larger Washington metropolitan area and the Northeast megalopolis.[123] Fairfax County is the most populous locality in the state, with more than 1.1 million residents, although that does not include its county seat Fairfax City, which is one of the independent cities.[124] Fairfax County has a major urban business and shopping center in Tysons Corner, Virginia's largest office market.[125] Neighboring Prince William County is Virginia's second most populous county, with a population exceeding 450,000, and is home to Marine Corps Base Quantico, the FBI Academy and Manassas National Battlefield Park. Loudoun County, with the county seat at Leesburg, is the fastest-growing county in the state.[124][126] Arlington County, the smallest self-governing county in the United States by land area, is an urban community organized as a county.[127]
+
+Richmond is the capital of Virginia, and its metropolitan area has a population over 1.2 million.[128] As of 2019[update], Virginia Beach is the most populous independent city in the Commonwealth, with Chesapeake and Norfolk second and third, respectively.[129] The three are part of the larger Hampton Roads metropolitan area, which has a population over 1.7 million people and is the site of the world's largest naval base, Naval Station Norfolk.[128][130] Suffolk, which includes a portion of the Great Dismal Swamp, is the largest city by area at 429.1 square miles (1,111 km2).[131] In western Virginia, Roanoke city and Montgomery County, part of the Blacksburg–Christiansburg metropolitan area, both have surpassed a population of over 100,000 since 2018.[132]
+
+The United States Census Bureau estimates that the state population was 8,535,519 on July 1, 2019, a 6.7 percent increase since the 2010 United States Census.[6] This includes an increase of 534,495 people into the Commonwealth since the 2010 census. Immigration from outside the United States resulted in a net increase of 159,627 people, and migration within the country produced a net increase of 155,205 people.[135] As of 2010[update], the center of population was located in Louisa County, near Richmond.[136]
+
+Aside from Virginia, the top birth state for Virginians is New York, having overtaken North Carolina in the 1990s, with the Northeast accounting for the largest number of migrants into the state by region.[137] The median age in 2018 was 38.4 years old, making the state just slightly older than the national average of 38.2.[138]
+
+The state's most populous ethnic group, Non-Hispanic whites, has declined as a proportion of population from 76 percent in 1990 to 61 percent in 2019, as other ethnicities have increased.[139][6] People of English heritage settled throughout the Commonwealth during the colonial period, and others of British and Irish heritage have since immigrated.[140] Those who identify on the census as having "American ethnicity" are predominantly of English descent, but have ancestors who have been in North America for so long they choose to identify simply as American.[141][142] Of the English immigrants to Virginia in the 17th century, three-fourths came as indentured servants.[143] The western mountains have many settlements that were founded by Scots-Irish immigrants before the American Revolution.[144][145] There are also sizable numbers of people of German descent in the northwestern mountains and Shenandoah Valley.[146] On the 2018 American Community Survey, eleven percent said they were of German ancestry.[147]
+
+The largest minority group in Virginia are African Americans, who include about one-fifth of the population.[6] Virginia was a major destination of the Atlantic slave trade, and the first generations of enslaved men, women and children were brought primarily from Angola and the Bight of Biafra. The Igbo ethnic group of what is now southern Nigeria were the single largest African group among slaves in Virginia.[148] Many African Americans also have European and Native American ancestry, often with asymmetrical male and female ancestry contribution.[149] Though the Black population was reduced by the Great Migration to northern industrial cities in the first half of the 20th century, since 1965 there has been a reverse migration of Blacks returning south.[150] According to the Pew Research Center, the state has the highest number of black-white interracial marriages in the United States,[151] and 3.1 percent of Virginians describe themselves as biracial.[6]
+
+More recent immigration in the late 20th century and early 21st century has resulted in new communities of Hispanics and Asians. Among international immigrants to Virginia, eleven percent were born in El Salvador, nine percent in India, six percent in South Korea and five percent each in Mexico and the Philippines, and 52 percent are U.S. citizens as of 2017[update].[152] As of 2019[update], 9.6 percent of Virginia's total population describe themselves as Hispanic or Latino, and 6.9 percent as Asian.[6] The state's Hispanic population rose by 92 percent from 2000 to 2010, with two-thirds of Hispanics in the state living in Northern Virginia.[153] Hispanic citizens in Virginia have higher median household incomes and educational attainment than the general state population.[154] Northern Virginia also has a significant population of Vietnamese Americans, whose major wave of immigration followed the Vietnam War.[155] Korean Americans have migrated more recently, attracted by the quality school system.[156] The Filipino American community has about 45,000 in the Hampton Roads area, many of whom have ties to the U.S. Navy and armed forces.[157]
+
+Additionally, 0.5 percent of Virginians are American Indian or Alaska Native, and 0.1 percent are Native Hawaiian or other Pacific Islander.[6] Virginia has extended state recognition to eleven Native American tribes resident in the state. Seven tribes also have federal recognition, including six that were recognized in 2018 after passage of bill named for activist Thomasina Jordan.[158][159] The Pamunkey and Mattaponi have reservations on tributaries of the York River in the Tidewater region.[160]
+
+American Community Survey five-year estimate
+
+As of 2010[update], 85.9% (6,299,127) of Virginia residents age five and older spoke English at home as a first language, while 14.1% (1,036,442) did not—6.4% (470,058) spoke Spanish, 0.8% (56,518) Korean, 0.6% (45,881) Vietnamese, 0.6% (42,418) Chinese (including Mandarin), and 0.6% (40,724) Tagalog.[161] English was passed as the Commonwealth's official language by statutes in 1981 and again in 1996, though the status is not mandated by the Constitution of Virginia.[162]
+
+The Piedmont region is known for its dialect's strong influence on Southern American English. While a more homogenized American English is found in urban areas, various accents are also used, including the Tidewater accent, the Old Virginia accent, and the anachronistic Elizabethan of Tangier Island.[163][164]
+
+Virginia is predominantly Christian and Protestant; Baptist denominations combined to form largest group with about 26 percent of the population as of 2014[update],[165] and around 763,655 total members as of 2010[update].[166] Baptist denominational groups in Virginia include the Baptist General Association of Virginia, with about 1,400 member churches, which supports both the Southern Baptist Convention and the moderate Cooperative Baptist Fellowship; and the Southern Baptist Conservatives of Virginia with more than 500 affiliated churches, which supports the Southern Baptist Convention.[167][168] Roman Catholics are the second-largest religious group with 673,853 members.[166] The Roman Catholic Diocese of Arlington includes most of Northern Virginia's Catholic churches, while the Diocese of Richmond covers the rest.
+
+The Virginia Conference is the regional body of the United Methodist Church in most of the Commonwealth, while the Holston Conference represents much of extreme Southwest Virginia. The Virginia Synod is responsible for the congregations of the Lutheran Church. Presbyterian, Pentecostal, Congregationalist, and Episcopalian adherents each comprised less than two percent of the population as of 2010[update].[166] The Episcopal Diocese of Virginia, Southern Virginia, and Southwestern Virginia support the various Episcopal churches.
+
+In November 2006, 15 conservative Episcopal churches voted to split from the Diocese of Virginia over the ordination of openly gay bishops and clergy in other dioceses of the Episcopal Church; these churches continue to claim affiliation with the larger Anglican Communion through other bodies outside the United States. Though Virginia law allows parishioners to determine their church's affiliation, the diocese claimed the secessionist churches' buildings and properties. The resulting property law case, ultimately decided in favor of the mainline diocese, was a test for Episcopal churches nationwide.[169]
+
+Among other religions, adherents of The Church of Jesus Christ of Latter-day Saints constitute one percent of the population, with two hundred congregations in Virginia as of 2017[update].[170] Fairfax Station is the site of the Ekoji Buddhist Temple, of the Jodo Shinshu school, and the Hindu Durga Temple. While the state's Jewish population is small, organized Jewish sites date to 1789 with Congregation Beth Ahabah.[171] Muslims are a growing religious group throughout the Commonwealth through immigration.[172] Megachurches in the Commonwealth include Thomas Road Baptist Church, Immanuel Bible Church, and McLean Bible Church.[173] Several Christian universities are also based in the state, including Regent University, Liberty University, and the University of Lynchburg.
+
+Virginia's economy has diverse sources of income, including local and federal government, military, farming and high-tech. Prior to the coronavirus recession, Virginia had 4.36 million people employed with an unemployment rate of 2.9 percent in March 2020,[174] but jobless claims due to the virus peaked in early April 2020, before falling slightly in May, when the state had 386,000 unemployed with a rate of 9.4 percent,[175] which was tied for the 11th-lowest nationwide.[176] The state's average earnings per job was $63,281, the 11th-highest nationwide,[177] and the gross domestic product (GDP) was $476.4 billion in 2018, the 13th-largest among U.S. states.[178] Canada is the state's leading international market, receiving 17.2 percent of exports.[179]
+
+Virginia has a median household income of $72,600, 11th-highest nationwide, and a poverty rate of 10.7 percent, 12th-lowest nationwide, as of 2018[update]. Montgomery County outside Blacksburg has the highest poverty rate in the state, with 28.5 percent falling below the U.S. Census poverty thresholds. Loudoun County meanwhile has the highest median household income in the nation, and the wider Northern Virginia region is among the highest-income regions nationwide.[180] As of 2013[update], six of the twenty highest-income counties in the United States, including the two highest,[181] as well as three of the fifty highest-income towns, are all located in Northern Virginia.[182] Though the Gini index shows Virginia has less income inequality than the national average,[183] the state's middle class is also smaller than the majority of states.[184]
+
+Virginia has the highest defense spending of any state per capita, providing the Commonwealth with around 900,000 jobs.[186][187] Approximately twelve percent of all U.S. federal procurement money is spent in Virginia, the second-highest amount after California.[187][188] Many Virginians work for federal agencies in Northern Virginia, which include the Central Intelligence Agency and the Department of Defense, as well as the National Science Foundation, the United States Geological Survey and the United States Patent and Trademark Office. Many others work for government contractors, including defense and security firms, which hold more than 15,000 federal contracts.[189]
+
+Virginia has one of the highest concentrations of veterans of any state,[190] and is second to California in total Department of Defense employees.[188][191] The Hampton Roads area has the largest concentration of military personnel and assets of any metropolitan area in the world,[192] including the largest naval base in the world, Naval Station Norfolk.[130] In its state government, Virginia employs 106,143 public employees, who combined have a median income of $44,656 as of 2013[update].[193]
+
+Virginia was home to 653,193 separate firms in the 2012 U.S. Census Survey of Business Owners, with 54% of those majority male-owned and 36.2% majority female-owned. Approximately 28.3% of firms were also majority minority-owned, and 11.7% were veteran-owned.[194] Twenty-one Fortune 500 companies are headquartered in Virginia as of 2019[update], with the largest companies by revenue being Freddie Mac, General Dynamics, and Capital One.[195] The largest by their number of employees are Dollar Tree in Chesapeake and Hilton Worldwide Holdings in McLean.[196]
+
+Virginia's business environment has been ranked highly by various publications. In 2019, CNBC named Virginia their Top State for Business, with its deductions being mainly for the high cost of living,[197] while Forbes magazine ranked it fourth, though number one in quality of life.[198] Additionally, in 2014 a survey of 12,000 small business owners found Virginia to be one of the most friendly states for small businesses.[199] Oxfam America however ranked Virginia last in their July 2018 ranking of best states to work in, largely due to a low minimum wage of $7.25, and the state's organized labor laws. Though the topic was debated during in the 2019–20 General Assembly session, Virginia has been a "right to work" state since 1947,[200] and an employment-at-will state since 1906.[201]
+
+Virginia has the highest concentration of technology workers of any state,[202] and the fourth-highest number of technology workers after California, Texas, and New York.[203] Computer chips became the state's highest-grossing export in 2006,[204] with a total export value of $694 million in 2019.[179] Northern Virginia, once considered the state's dairy capital, now hosts software, communication technology, defense contracting companies, particularly in the Dulles Technology Corridor and Tysons Corner areas. The state has the highest average and peak Internet speeds in the United States, with the third-highest worldwide.[205] Northern Virginia's data centers can carry up to seventy percent of the nation's Internet traffic,[206] and in 2015 the region was the largest and fastest growing data center market in the nation.[207][208]
+
+Tourism in Virginia supported an estimated 234,000 jobs in 2018, making tourism the state's fifth largest industry. It generated $26 billion, an increase 4.4 percent from 2017.[209] The state was eighth nationwide in domestic travel spending in 2018, with Arlington County the top tourist destination in the state by domestic spending, followed by Fairfax County, Loudoun County, and Virginia Beach.[210] Virginia also saw 1.1 million international tourists in 2018, a five percent increase from 2017.[211]
+
+As of 2017[update], agriculture occupied 28 percent of the land in Virginia with 7.8 million acres (12,188 sq mi; 31,565 km2) of farmland. Nearly 54,000 Virginians work on the state's 43,225 farms, which average 181 acres (0.28 sq mi; 0.73 km2). Though agriculture has declined significantly since 1960 when there were twice as many farms, it remains the largest single industry in Virginia, providing for over 334,000 jobs.[213] Soybeans were the most profitable crop in Virginia in 2017, ahead of corn and cut flowers as other leading agricultural products.[214] However, the ongoing China-U.S. trade war led many Virginia farmers to plant cotton instead of soybeans in 2019.[215] Though it is no longer the primary crop, Virginia is still the third-largest producer of tobacco in the United States.[213]
+
+Virginia is also the country's third-largest producer of seafood as of 2018[update], with sea scallops, oysters, Chesapeake blue crabs, menhaden, and hardshell clams as the largest seafood harvests by value, and France, Canada, and Hong Kong as the top export destinations.[216][217] Commercial fishing supports 18,220 jobs as of 2020[update], while recreation fishing supports another 5,893.[218] Eastern oyster harvests had increased from 23,000 bushels in 2001 to over 500,000 in 2013,[219] but fell to 248,347 in 2019 because of low salinity in coastal waters due to heavy spring rains.[220] Those same rains however made 2019 a record wine harvest for vineyards in the Northern Neck and along the Blue Ridge Mountains, which also attract 2.3 million tourists annually.[221][222] Virginia has the seventh-highest number of wineries in the nation, with 307 as of January 2020[update].[223] Cabernet franc and Chardonnay are the most grown varieties.[224]
+
+Virginia collects personal income tax from those with incomes above a filing threshold; there are five income brackets, with rates ranging from 2.0% to 5.75% of taxable income.[225][226] The state sales and use tax rate is 4.3%. There is an additional 1% local tax, for a total of a 5.3% combined sales tax on most Virginia purchases. The sales tax rate is  higher in three regions: Northern Virginia (6%), Hampton Roads (6%) and the Historic Triangle (7%).[227] Unlike the majority of states, Virginia collects sales tax on groceries, but at a lower rate than the general sales tax;[228] the sales tax for food and certain essential personal hygiene goods is 2.5%.[227]
+
+Virginia's property tax is set and collected at the local government level and varies throughout the Commonwealth. Real estate is also taxed at the local level based on one hundred percent of fair market value.[229] As of fiscal year 2018, the median real estate tax rate per $100 of assessed taxable value was $1.07 for cities, $0.67 for counties, and $0.17 for towns; town rates are lower because towns (unlike cities) have a narrow range of responsibilities and are subordinate to counties.[230] Of local government tax revenue, about 61% is generated from real property taxes; about 24% from tangible personal property, sales and use, and business license tax; and 15% from other taxes (such as restaurant meal taxes, public service corporation property tax, consumer utility tax, and hotel tax).[231]
+
+Virginia's culture was popularized and spread across America and the South by figures such as George Washington, Thomas Jefferson, and Robert E. Lee. Their homes in Virginia represent the birthplace of America and the South.[232] Modern Virginia culture has many sources, and is part of the culture of the Southern United States.[233] The Smithsonian Institution divides Virginia into nine cultural regions.[234]
+
+Besides the general cuisine of the Southern United States, Virginia maintains its own particular traditions. Virginia wine is made in many parts of the commonwealth.[222] Smithfield ham, sometimes called "Virginia ham", is a type of country ham which is protected by state law, and can be produced only in the town of Smithfield.[235] Virginia furniture and architecture are typical of American colonial architecture. Thomas Jefferson and many of the commonwealth's early leaders favored the Neoclassical architecture style, leading to its use for important state buildings. The Pennsylvania Dutch and their style can also be found in parts of the commonwealth.[146]
+
+Literature in Virginia often deals with the commonwealth's extensive and sometimes troubled past. The works of Pulitzer Prize winner Ellen Glasgow often dealt with social inequalities and the role of women in her culture.[236] Glasgow's peer and close friend James Branch Cabell wrote extensively about the changing position of gentry in the Reconstruction era, and challenged its moral code with Jurgen, A Comedy of Justice.[237] William Styron approached history in works such as The Confessions of Nat Turner and Sophie's Choice.[238] Tom Wolfe has occasionally dealt with his southern heritage in bestsellers like I Am Charlotte Simmons.[239] Mount Vernon native Matt Bondurant received critical acclaim for his historic novel The Wettest County in the World about moonshiners in Franklin County during prohibition.[240] Virginia also names a state Poet Laureate.[241]
+
+Rich in cultural heritage, Virginia however ranks near the bottom of U.S. states in terms of public spending on the arts, at nearly half of the national average.[242] The state government does fund some institutions, including the Virginia Museum of Fine Arts and the Science Museum of Virginia. Other museums include the popular Steven F. Udvar-Hazy Center of the National Air and Space Museum and the Chrysler Museum of Art.[243] Besides these sites, many open-air museums are located in the Commonwealth, such as Colonial Williamsburg, the Frontier Culture Museum, and various historic battlefields.[244] The Virginia Foundation for the Humanities works to improve the Commonwealth's civic, cultural, and intellectual life.[245]
+
+Theaters and venues in the Commonwealth are found both in the cities and in suburbs. The Harrison Opera House, in Norfolk, is home of the Virginia Opera. The Virginia Symphony Orchestra operates in and around Hampton Roads.[246] Resident and touring theater troupes operate from the American Shakespeare Center in Staunton.[247] The Barter Theatre in Abingdon, designated the State Theatre of Virginia, won the first Regional Theatre Tony Award in 1948, while the Signature Theatre in Arlington won it in 2009. There is also a Children's Theater of Virginia, Theatre IV, which is the second largest touring troupe nationwide.[248] Notable music performance venues include The Birchmere, the Landmark Theater, and Jiffy Lube Live.[249] Wolf Trap National Park for the Performing Arts is located in Vienna and is the only national park intended for use as a performing arts center.[250]
+
+Virginia has launched many award-winning traditional musical artists and internationally successful popular music acts, as well as Hollywood actors.[1] Virginia is known for its tradition in the music genres of old-time string and bluegrass, with groups such as the Carter Family and Stanley Brothers.[251] The state's African tradition is found through gospel, blues, and shout bands, with both Ella Fitzgerald and Pearl Bailey coming from Newport News.[252] Contemporary Virginia is also known for folk rock artists like Dave Matthews and Jason Mraz, hip hop stars like Pharrell Williams, Missy Elliott and Pusha T, as well as thrash metal groups like GWAR and Lamb of God.[253] Several members of country music band Old Dominion grew up in the Roanoke area, and took their band name from Virginia's state nickname.[254]
+
+Many counties and localities host county fairs and festivals. The Virginia State Fair is held at the Meadow Event Park every September. Also in September is the Neptune Festival in Virginia Beach, which celebrates the city, the waterfront, and regional artists. Norfolk's Harborfest, in June, features boat racing and air shows.[255] Fairfax County also sponsors Celebrate Fairfax! with popular and traditional music performances.[256] The Virginia Lake Festival is held during the third weekend in July in Clarksville.[257] Wolf Trap hosts the Wolf Trap Opera Company, which produces an opera festival every summer.[250] Each September, Bay Days celebrates the Chesapeake Bay as well as Hampton's 400-year history since 1610, and Isle of Wight County holds a County Fair on the second week of September as well. Both feature live music performances, and other unique events.
+
+On the Eastern Shore island of Chincoteague the annual Pony Swim & Auction of feral Chincoteague ponies at the end of July is a unique local tradition expanded into a week-long carnival. The Shenandoah Apple Blossom Festival is a six-day festival held annually in Winchester which includes parades and bluegrass concerts. The Old Time Fiddlers' Convention in Galax, begun in 1935, is one of the oldest and largest such events worldwide. Two important film festivals, the Virginia Film Festival and the VCU French Film Festival, are held annually in Charlottesville and Richmond, respectively.[258]
+
+The Hampton Roads area is the 42nd-largest media market in the United States as ranked by Nielsen Media Research, while the Richmond-Petersburg area is 54th and Roanoke-Lynchburg is 69th as of 2020[update].[259] Northern Virginia is part of the much larger Washington, D.C. media market.
+
+There are 36 television stations in Virginia, representing each major U.S. network, part of 42 stations which serve Virginia viewers including those broadcasting from neighboring jurisdictions.[260] According the Federal Communications Commission, 595 FCC-licensed FM radio stations broadcast in Virginia, with 239 such AM stations as of 2020[update].[261][262] The nationally available Public Broadcasting Service (PBS) is headquartered in Arlington. Independent PBS affiliates exist throughout Virginia, and the Arlington PBS member station WETA-TV produces programs such as the PBS NewsHour and Washington Week.
+
+The most circulated native newspapers in the Commonwealth are Norfolk's The Virginian-Pilot with around 132,000 subscribers,[263] the Richmond Times-Dispatch with 86,219,[264] and The Roanoke Times as of 2018[update].[265] The paper with nation's most daily readers, USA Today, with 520,000 daily subscriptions, is headquartered in McLean.[266] USA Today is the flagship publication of Gannett, Inc., which merged with GateHouse Media in 2019, and operates over one hundred local newspapers nationwide.[267] In Northern Virginia, The Washington Post is the dominant newspaper and provides local coverage for the region.[268] Politico, which covers national politics, has its offices in Rosslyn.[269]
+
+Virginia's educational system consistently ranks in the top five states on the U.S. Department of Education's National Assessment of Educational Progress, with Virginia students outperforming the average in all subject areas and grade levels tested.[270] The 2019 Quality Counts report ranked Virginia's K–12 education third in the country, with a letter grade of B.[271][272] All school divisions must adhere to educational standards set forth by the Virginia Department of Education, which maintains an assessment and accreditation regime known as the Standards of Learning to ensure accountability.[273]
+
+Public K–12 schools in Virginia are generally operated by the counties and cities, and not by the state. As off the 2018–19 academic year,[update] a total of 1,290,576 students were enrolled in 2,293 local and regional schools in the Commonwealth, including eight charter schools, and an additional 98 alternative and special education centers across 133 school divisions.[274][275] 2018 marked the first decline in overall enrollment in public schools, by just over 2,000 students, since 1984.[276] Besides the general public schools in Virginia, there are Governor's Schools and selective magnet schools. The Governor's Schools are a collection of more than 40 regional high schools and summer programs intended for gifted students.[277] The Virginia Council for Private Education oversees the regulation of 483 state accredited private schools.[278] An additional 17,283 students receive homeschooling.[279]
+
+In 2019, 91.5 percent of high school students graduated on-time after four years,[280] an increase of two percent from 2013,[281] and 89.3 percent of adults over the age 25 had their high school diploma.[6] Virginia has one of the smaller racial gaps in graduation rates among U.S. states,[282] with 89.7 percent of Black students graduating on time, compared to 94.7 percent  of white students and 97.5 percent of Asian students.[280] Despite ending school segregation in the 1960s, seven percent of Virginia's public schools were rated as "intensely segregated" by The Civil Rights Project at UCLA in 2019, and the number has risen since 1989, when only three percent were.[283] Virginia has comparatively large public school districts, typically comprising entire counties or cites, and this helps mitigate funding gaps seen in other states such that non-white districts average slightly more funding, $255 per student as of 2019[update], than majority white districts.[284]
+
+As of 2019[update], Virginia has the sixth highest percent of residents with bachelors degrees or higher, with 38.2 percent.[6] As of that year, there are 169 colleges and universities in Virginia.[286] In the 2019 U.S. News & World Report ranking of national public universities, the University of Virginia is ranked No. 3, the College of William and Mary is No. 10, Virginia Tech is No. 30, George Mason University is No. 67, and Virginia Commonwealth University is No. 80.[287] James Madison University is ranked the No. 6 regional university in The South.[288] There are 124 private institutions in the state, including nationally ranked liberal arts colleges Washington and Lee University at No. 11, the University of Richmond at No. 25, and the Virginia Military Institute at No. 81.[286][289]
+
+Virginia Tech and Virginia State University are the state's land-grant universities. The Virginia Military Institute is the oldest state military college.[290] Virginia also operates 23 community colleges on 40 campuses which enrolled more than 228,000 degree-seeking students during the 2018–2019 school year.[291] As of 2019[update], George Mason University had the largest on-campus enrollment at 37,677 students,[292] though the private Liberty University had the largest total enrollment in the state, with 88,283 online and 15,105 on-campus students in Lynchburg.[293]
+
+Virginia has a mixed health record, and was ranked as the 15th overall healthiest state according to the 2019 United Health Foundation's Health Rankings. Virginia was 19th lowest among U.S. states in its number of premature deaths, with 6,914 per 100,000, and 24th with an infant mortality rate of 5.9 per 1,000 live births.[42] There are however racial and social health disparities. With high rates of heart disease and diabetes, African Americans in Virginia had an average life expectancy 4 years lower than whites and 12 years lower than Asian Americans and Latinos in 2017,[296] and were disproportionately affected by COVID-19 during the coronavirus pandemic.[297] African-American mothers are also three times more likely to die while giving birth in the state.[298] Mortality rates among white middle-class Virginians have also been rising, with drug overdose, suicide, and alcohol poisoning as leading causes.[299]
+
+Weight is an issue for many Virginians, and 30.3% of adults and 13.2% of 10- to 17-year-olds are obese as of 2019[update].[42][300] Additionally, 35% of adults are overweight and 23.3% do not exercise regularly.[301] Virginia banned smoking in bars and restaurants in January 2010,[302] and the percent of tobacco smokers in the state has declined from 19% in that year to 14.9% in 2019. Virginia does have among the highest rates of immunization nationwide, ranking 6th for childhood immunization and 14th for both TDaP and HPV vaccines per capita.[42] Virginia was the first U.S. state to mandate HPV vaccination for girls for school attendance, which it did in 2008.[303]
+
+There are 90 hospitals in Virginia with a combined 17,706 hospital beds as of 2020[update].[304] Notable examples include Inova Fairfax Hospital, the largest hospital in the Washington Metropolitan Area, and the VCU Medical Center, located on the medical campus of Virginia Commonwealth University. The University of Virginia Medical Center, part of the University of Virginia Health System, is highly ranked in endocrinology according to U.S. News & World Report.[305] Virginia has a ratio of 148.1 primary care physicians per 10,000 residents, which is the 24th highest nationally, but only 171.9 mental health providers per that number, the 10th lowest nationwide. The rate of uninsured Virginians dropped to 8.8% after the state government passed Medicare expansion in 2019.[42]
+
+Because of the 1932 Byrd Road Act, the state government controls most of Virginia's roads, instead of a local county authority as is usual in other states.[307] As of 2018[update], the Virginia Department of Transportation owns and operates 57,867 miles (93,128 km) of the total 70,105 miles (112,823 km) of roads in the state, making it the third largest state highway system in the United States.[308] Although the Washington Metropolitan Area, which includes Northern Virginia, has the second highest rate of traffic congestion in the nation, Virginia as a whole has the 21st-lowest rate of congestion and the average commute time is 26.9 minutes.[309][310] Virginia hit peak car usage before the year 2000, making it one of the first such states.[311]
+
+Virginia has Amtrak passenger rail service along several corridors, and Virginia Railway Express (VRE) maintains two commuter lines into Washington, D.C. from Fredericksburg and Manassas. VRE is one of the nation's fastest growing commuter rail services, handling nearly 20,000 passengers a day.[312] Arlington accounted for forty percent of Virginia's public transit trips as of 2013[update], with most of that being from the Washington Metro transit system, which also serves Alexandria and communities in Fairfax County along I-66.[313] The system is currently expanding west into additional areas of Loudoun County.[314] Major freight railroads in Virginia include Norfolk Southern and CSX Transportation. Commuter buses include the Fairfax Connector, FRED buses in Fredericksburg, and OmniRide in Prince William County.[315] The Virginia Department of Transportation operates several free ferries throughout Virginia, the most notable being the Jamestown Ferry which connects Jamestown to Scotland Wharf across the James River.[316]
+
+Virginia has five major airports: Washington Dulles International and Reagan Washington National in Northern Virginia, both of which handle more than twenty million passengers a year; Richmond International; and Newport News/Williamsburg International Airport and Norfolk International serving the Hampton Roads area. Several other airports offer limited commercial passenger service, and sixty-six public airports serve the state's aviation needs.[317] The Virginia Port Authority's main seaports are those in Hampton Roads, which carried 69,416,600 short tons (62,973,700 t) of total cargo in 2018[update], the fifth most of United States ports.[318] The Eastern Shore of Virginia is the site of Wallops Flight Facility, a rocket testing center owned by NASA, and the Mid-Atlantic Regional Spaceport, a commercial spaceport.[319][320] Space tourism is also offered through Vienna-based Space Adventures.[321]
+
+In 1619, the first Virginia General Assembly met at Jamestown Church, and included 22 locally elected representatives, making Virginia's legislature the oldest in the North America.[8] These representatives became a formal House of Burgesses in 1642 and governed with the crown-appointed Governor's Council until Virginia declared independence in 1776. The current General Assembly is the 161st since that year. The government today functions under the seventh Constitution of Virginia, which was approved by voters in 1971 and is similar to the federal structure in that it provides for three branches: a strong legislature, an executive, and a unified judicial system.[322]
+
+Virginia's legislature is bicameral with a 100-member House of Delegates and 40-member Senate, who together write the laws for the Commonwealth. Delegates serve two-year terms, while senators serve four-year terms, with the most recent elections for both taking place in November 2019. The legislature meets annually starting on the second Wednesday of the year, typically for 60 days in even years and 48 days in odd years due to the state's biannual budgeting, though special sessions can be called either by the governor or with agreement of two-thirds of both houses.[323] Special sessions are common, and have been called in 2019 and 2020 for topics such as gun control, the impact of the coronavirus on the state budget, and police reform.[324][325]
+
+The executive department includes the governor and lieutenant governor, who are elected every four years in separate elections, with the next taking place in November 2021. The governor must be at least 30 years old and incumbent governors cannot run for re-election, however the lieutenant governor and attorney general can, and governors can and have served non-consecutive terms.[322] The lieutenant governor is the official head of the Senate, and is responsible for breaking ties. The House elects a Speaker of the House and the Senate elects a President pro tempore, who presides when the lieutenant governor isn't present, and both houses elect a clerk and majority and minority leaders.[323] State budgets are proposed in even years by the governor.[326] Based on data through 2018, the Pew Center on the States found the state government to be above average in running surpluses,[327] while U.S. News and World Report ranked the state eighth in fiscal stability.[328]
+
+The judges and justices who make up Virginia's judicial system, also the oldest in America, are elected by a majority vote in both the House and Senate without input from the governor, one way Virginia's legislature is stronger than its executive. The system consists of a hierarchy from the Supreme Court of Virginia and the Court of Appeals of Virginia to the Circuit Courts, the trial courts of general jurisdiction, and the lower General District Courts and Juvenile and Domestic Relations District Courts.[329] The Supreme Court has seven justices who serve twelve-year terms, with a mandatory retirement age of 73. The Supreme Court selects its own Chief Justice from among their seven members, who is informally limited to two four-year terms.[330]
+
+The Code of Virginia is the statutory law, and consists of the codified legislation of the General Assembly. The Virginia State Police is the largest law enforcement agency in Virginia. The Virginia Capitol Police is the oldest police department in the United States.[331] The Virginia National Guard consists of 7,500 soldiers in the Virginia Army National Guard and 1,200 airmen in the Virginia Air National Guard.[332] Since the resumption of capital punishment in Virginia in 1982, 113 people have been executed, the second highest number in the nation, and three inmates are on the state's death row as of 2019[update].[333] Virginia has the fourth lowest violent crime rate and 13th-lowest property crime rate as of 2018[update] according to FBI data.[334] Since Virginia ended prisoner parole in 1995, the rate of recidivism has fallen to 23.4 percent in 2019, the lowest nationwide.[335]
+
+Over the 20th century, Virginia shifted from a largely rural, politically Southern and conservative state to a more urbanized, pluralistic, and politically moderate environment. Up until the 1970s, Virginia was a racially divided one-party state dominated by the Byrd Organization,[337] which sought to stymie the political power of Northern Virginia, perpetuate segregation, and restrict voter registration.[338] The organization used  malapportionment to control what areas of the state were over-represented in the General Assembly and the U.S. Congress until ordered to end the practice by the 1964 U.S. Supreme Court decision in Davis v. Mann and the 1965 the Virginia Supreme Court decision in Wilkins v. Davis respectively.[339]
+
+Passage of Federal civil rights legislation in the mid-1960s, including the Voting Rights Act of 1965, helped end the state's Jim Crow laws which effectively disfranchised African Americans.[340] Greater enfranchisement and demographic shifts further changed the electorate. In 1980, 56 percent of eligible voters were born in the state; in 2019 that number was 45 percent, a result of strong international immigration and domestic migration into the state.[341]
+
+Regional differences also play a large part in Virginia politics.[342] While urban and growing suburban areas, including much of Northern Virginia, form the Democratic Party base, rural southern and western areas moved to support the Republican Party in response to its "southern strategy".[343][344] Rural Democratic support has nevertheless persisted in union-influenced Roanoke in Southwest Virginia, college towns such as Charlottesville and Blacksburg, and the southeastern Black Belt Region.[345] State election seasons traditionally start with the annual Shad Planking event in Wakefield.[336]
+
+State elections in Virginia occur in odd-numbered years, with executive department elections occurring in years following U.S. presidential elections and Senate elections occurring in the years prior to presidential elections, as both have four-year terms. House of Delegates elections take place concurrent with each of those elections as members have two-year terms. National politics often play a role in state election outcomes, and Virginia has elected governors of the party opposite the U.S. president in ten of the last eleven contests, with only Terry McAuliffe beating the trend.[346][347]
+
+McAuliffe, a Democrat, was elected Governor in the 2013 elections by two percentage points during Barack Obama's second presidential term.[348] Republicans, however, held a super-majority (68–32) of seats in the House of Delegates, which they had first gained in the 2011 state elections.[349] Republicans also held a one-vote majority the state senate, which they then maintained in the 2015 election.[350] Eleven house district lines used in these elections, drawn following the 2010 U.S. Census, were later judged unconstitutional for discriminating against African Americans.[351]
+
+The 2017 statewide elections resulted in Democrats holding the three highest offices, with outgoing lieutenant governor Ralph Northam winning the governorship, Justin Fairfax elected lieutenant governor, and Mark Herring continuing as attorney general. In concurrent House of Delegates elections, Democrats flipped fifteen of the Republicans' previous sixteen-seat majority.[352] Control of the House came down to the tied election in the 94th district, which was won by Republicans through drawing of lots, giving the party a slim 51–49 majority in the 2018–19 legislative sessions.[353] Despite a political crisis that February, Democrats took full control of the General Assembly in the November 2019 elections,[354] the first after several districts were redrawn because of discrimination.[355]
+
+In federal elections since 2006, both parties have seen successes. Republican Senator George Allen lost close races in 2006, to Democratic newcomer Jim Webb, and again in 2012, to Webb's replacement, former Governor Tim Kaine.[356] In 2008, Democrats won both United States Senate seats; former Governor Mark Warner was elected to replace retiring Republican John Warner.[357] In the 2010 mid-term elections, the first under President Obama, Republicans flipped three United States House of Representatives seats from the Democrats, while in the 2018 mid-terms, the first under President Trump, Democrats flipped three seats from Republicans. Of the state's eleven seats in the House of Representatives, Democrats currently hold seven and Republicans hold four.
+
+Though Virginia was considered a "swing state" in recent presidential elections,[7] Democrat Barack Obama carried Virginia's 13 electoral votes in 2008 and 2012,[358] while Democrat Hillary Clinton carried the state in 2016. Virginia had previously voted for Republican presidential candidates in 13 out of 14 presidential elections from 1952 to 2004, including 10 in a row from 1968 to 2004.[7] Virginia currently holds its presidential primary election on Super Tuesday, the same day as thirteen other states, with the most recent held on March 3, 2020.[359]
+
+Virginia is the most populous U.S. state without a major professional sports league franchise.[360] The reasons for this include the lack of any dominant city or market within the state, the proximity of teams in Washington, D.C. and North Carolina, and a reluctance to publicly finance stadiums.[361][362] A proposed arena in Virginia Beach designed for an NBA franchise became the latest unsuccessful sports initiative when the city council there ended support in 2017.[363] Norfolk is however host to two minor league teams: The AAA Norfolk Tides and the ECHL's Norfolk Admirals. The San Francisco Giants' AA team, the Richmond Flying Squirrels, began play at The Diamond in 2010, replacing the AAA Richmond Braves, who relocated after 2008.[364] Additionally, the Washington Nationals, Boston Red Sox, Cleveland Indians, Atlanta Braves, Pittsburgh Pirates, New York Yankees, and Toronto Blue Jays also have Single-A and Rookie-level farm teams in Virginia.[365] The Richmond Kickers, a United Soccer League club, have operated since 1993 and are the only team in their league to win both the league championship and the U.S. Open Cup in the same year.[366]
+
+The Washington Football Team have their headquarters in Ashburn and their training facility is in Richmond,[367] and the Washington Capitals train at MedStar Capitals Iceplex in Ballston. Virginia has many professional caliber golf courses including the Greg Norman course at Lansdowne Resort and Kingsmill Resort, home of the Kingsmill Championship, an LPGA Tour tournament. NASCAR currently schedules Monster Energy NASCAR Cup races on two tracks in Virginia: Martinsville Speedway and Richmond Raceway. Virginia natives currently competing in the series include Denny Hamlin and Elliott Sadler.[368]
+
+Virginia does not allow state appropriated funds to be used for either operational or capital expenses for intercollegiate athletics.[370] Despite this, both the Virginia Cavaliers and Virginia Tech Hokies have been able to field competitive teams in the Atlantic Coast Conference and maintain modern facilities. Their rivalry is followed statewide. Twelve other universities compete in NCAA Division I, particularly in the Atlantic 10 Conference, Big South Conference, and Colonial Athletic Association. Three historically Black schools compete in the Division II Central Intercollegiate Athletic Association, and two others (Hampton and Norfolk State) compete in Division I. Several smaller schools compete in the Old Dominion Athletic Conference and the USA South Athletic Conference of NCAA Division III. The NCAA currently holds its Division III championships in football, men's basketball, volleyball and softball in Salem.[371]
+
+The state nickname is its oldest symbol, though it has never been made official by law. Virginia was given the title "Dominion" by King Charles II of England at the time of The Restoration, because it had remained loyal to the crown during the English Civil War, and the present moniker, "Old Dominion" is a reference to that title. Charles' supporters were called Cavaliers, and "The Cavalier State" nickname was popularized after the American Civil War to romanticize the antebellum period. Sports teams from the University of Virginia are called the Cavaliers.[372] The other nickname, "Mother of Presidents", is also historic, as eight Virginians have served as President of the United States, including four of the first five.[1]
+
+The state's motto, Sic Semper Tyrannis, translates from Latin as "Thus Always to Tyrants", and is used on the state seal, which is then used on the flag. While the seal was designed in 1776, and the flag was first used in the 1830s, both were made official in 1930.[373] The majority of the other symbols were made official in the late 20th century.[374] The Virginia reel is among the square dances classified as the state dance.[375] In 1940, Virginia made "Carry Me Back to Old Virginny" the state song, but it was retired in 1997 due to its references to slavery. In March 2015, Virginia named "Our Great Virginia", which uses the tune of "Oh Shenandoah", as the traditional state song and "Sweet Virginia Breeze" as the popular state song.[376]

en/6005.html.txt

@@ -0,0 +1,201 @@
+Coordinates: 38°N 79°W / 38°N 79°W / 38; -79
+
+Virginia (/vərˈdʒɪniə/ (listen)), officially the Commonwealth of Virginia, is a state in the Southeastern[4] and Mid-Atlantic[5] regions of the United States located between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth are shaped by the Blue Ridge Mountains and the Chesapeake Bay, which provide habitat for much of its flora and fauna. The capital of the Commonwealth is Richmond; Virginia Beach is the most populous city, and Fairfax County is the most populous political subdivision. The Commonwealth's estimated population as of 2019[update] is over 8.54 million.[6]
+
+The area's history begins with several indigenous groups, including the Powhatan. In 1607 the London Company established the Colony of Virginia as the first permanent English colony in the New World. Virginia's state nickname, the Old Dominion, is a reference to this status. Slave labor and the land acquired from displaced Native American tribes each played a significant role in the colony's early politics and plantation economy. Virginia was one of the 13 Colonies in the American Revolution. In the American Civil War, Virginia's Secession Convention resolved to join the Confederacy while the First Wheeling Convention resolved to remain in the Union, leading to a split that created West Virginia. Although the Commonwealth was under one-party rule for nearly a century following Reconstruction, both major national parties are competitive in modern Virginia.[7]
+
+Virginia's state legislature is the Virginia General Assembly, which was established in 1619 and is the oldest continuous law-making body in North America. It is made up of a 40-member Senate and a 100-member House of Delegates.[8] The state government is unique in how it treats cities and counties equally, manages local roads, and prohibits governors from serving consecutive terms. Virginia's economy has many sectors: agriculture in the Shenandoah Valley; federal agencies in Northern Virginia, including the headquarters of the U.S. Department of Defense and Central Intelligence Agency; and military facilities in Hampton Roads, the site of the region's main seaport.
+
+Virginia has a total area of 42,774.2 square miles (110,784.7 km2), including 3,180.13 square miles (8,236.5 km2) of water, making it the 35th-largest state by area.[9] Virginia is bordered by Maryland and Washington, D.C. to the north and east; by the Atlantic Ocean to the east; by North Carolina to the south; by Tennessee to the southwest; by Kentucky to the west; and by West Virginia to the north and west. Virginia's boundary with Maryland and Washington, D.C. extends to the low-water mark of the south shore of the Potomac River.[10]
+
+The state's southern border is defined as 36°30' north latitude, though surveyor error in the 1700s led to deviations of as much as three arcminutes.[11] From 1802 to 1803, a commission appointed by Virginia and Tennessee surveyed the area and set their border as a line from the summit of White Top Mountain to the top of the Cumberland Mountains. Errors discovered in 1856 led Virginia to propose a new surveying commission in 1871, but in 1893 the U.S. Supreme Court decided in favor of the 1803 line in the case Virginia v. Tennessee.[12][13] One result of this is the division of the city of Bristol between the two states.[14]
+
+The Chesapeake Bay separates the contiguous portion of the Commonwealth from the two-county peninsula of Virginia's Eastern Shore. The bay was formed from the drowned river valleys of the Susquehanna River and the James River.[15] Many of Virginia's rivers flow into the Chesapeake Bay, including the Potomac, Rappahannock, York, and James, which create three peninsulas in the bay.[16] Sea level rise has eroded the land on Virginia's islands, which include Tangier Island in the bay and Chincoteague, one of 23 barrier islands on the Atlantic coast.[17][18]
+
+The Tidewater is a coastal plain between the Atlantic coast and the fall line. It includes the Eastern Shore and major estuaries of Chesapeake Bay. The Piedmont is a series of sedimentary and igneous rock-based foothills east of the mountains which were formed in the Mesozoic era.[20] The region, known for its heavy clay soil, includes the Southwest Mountains around Charlottesville.[21] The Blue Ridge Mountains are a physiographic province of the Appalachian Mountains with the highest points in the commonwealth, the tallest being Mount Rogers at 5,729 feet (1,746 m).[2] The Ridge and Valley region is west of the mountains and includes the Great Appalachian Valley. The region is carbonate rock based and includes Massanutten Mountain.[22] The Cumberland Plateau and the Cumberland Mountains are in the southwest corner of Virginia, south of the Allegheny Plateau. In this region, rivers flow northwest, with a dendritic drainage system, into the Ohio River basin.[23]
+
+The Virginia Seismic Zone has not had a history of regular earthquake activity. Earthquakes are rarely above 4.5 in magnitude, because Virginia is located away from the edges of the North American Plate. A 5.8 magnitude earthquake struck central Virginia on August 23, 2011, near Mineral, and was the state's largest in at least a century.[24] Due to the area's geologic properties, the earthquake was felt from Northern Florida to Southern Ontario.[25] 35 million years ago, a bolide impacted what is now eastern Virginia. The resulting Chesapeake Bay impact crater may explain what earthquakes and subsidence the region does experience.[26]
+
+Coal mining takes place in the three mountainous regions at 45 distinct coal beds near Mesozoic basins.[27] More than 64 million tons of other non-fuel resources, such as slate, kyanite, sand, or gravel, were also mined in Virginia in 2018[update].[28] The commonwealth's carbonate rock is filled with more than 4,000 caves, ten of which are open for tourism, including the popular Luray Caverns and Skyline Caverns.[29]
+
+Virginia has a humid subtropical climate that transitions to humid continental west of the Blue Ridge Mountains.[30] Seasonal extremes vary from average lows of 25 °F (−4 °C) in January to average highs of 86 °F (30 °C) in July.[31] The Atlantic Ocean and Gulf Stream have a strong effect on eastern and southeastern coastal areas of the commonwealth, making the climate there warmer and more constant. Most of Virginia's recorded extremes in temperature and precipitation have occurred in the Blue Ridge Mountains and areas west.[32] Virginia receives an average of 43.34 inches (110 cm) of precipitation annually,[31] with the Shenandoah Valley being the state's driest region due to the mountains on either side.[32]
+
+Virginia has around 35–45 days with thunderstorms annually, and storms are common in the late afternoon and evenings between April and September.[33] These months are also the most common for tornadoes, 19 of which touched down in the state in 2019.[34] Hurricanes and tropical storms can occur from August to October, and though they typically impact coastal regions, the deadliest natural disaster in Virginia was Hurricane Camille, which killed over 150 people in 1969, mainly inland in Nelson County.[32][35] Between December and March, cold-air damming caused by the Appalachian Mountains can lead to significant snowfalls across the state, such as the January 2016 blizzard, which created the state's highest recorded snowfall of 36.6 inches (93 cm) near Bluemont.[36][37] Virginia only received 13.1 inches (33 cm) of snow during winter 2018–19, just above the state's average of 10 inches (25 cm).[38]
+
+Climate change in Virginia is leading to higher temperatures year-round as well as more heavy rain and flooding events.[39] Urban heat islands can be found in many Virginia cities and suburbs, particularly in neighborhoods linked to historic redlining.[40] Arlington had the most code orange days in 2019 for high ozone pollution in the air, with 12, followed by Fairfax County with 7.[41] Exposure of particulate matter in Virginia's air has decreased 49% from 13.5 micrograms per cubic meter in 2003 to 6.9 in 2019.[42] The closure and conversion of coal power plants in Virginia and the Ohio Valley region has reduced haze in the mountains, which peaked in 1998.[43] Virginia's 6 coal power plants must shut down by 2025,[44] and current plans call for 30 percent of the state's electricity to be renewable by 2030 and for all of it to be carbon-free by 2050.[45]
+
+Forests cover 62 percent of Virginia as of 2019[update], of which 78 percent is considered hardwood forest, meaning that trees in Virginia are primarily deciduous and broad-leaved. The other 22 percent is pine, with Loblolly and shortleaf pine dominating much of central and eastern Virginia.[46] In the western and mountainous parts of the commonwealth, oak and hickory are most common, while lower altitudes are more likely to have small but dense stands of moisture-loving hemlocks and mosses in abundance.[32] Gypsy moth infestations in oak trees and the blight in chestnut trees have decreased both of their numbers, leaving more room for hickory and invasive ailanthus trees.[47][32] In the lowland tidewater and Piedmont, yellow pines tend to dominate, with bald cypress wetland forests in the Great Dismal and Nottoway swamps.[46] Other common trees and plants include red bay, wax myrtle, dwarf palmetto, tulip poplar, mountain laurel, milkweed, daisies, and many species of ferns. The largest areas of wilderness are along the Atlantic coast and in the western mountains, where the largest populations of trillium wildflowers in North America are found.[32][48]
+
+Virginia is home to more than one million white-tailed deer, whose population have rebounded from an estimated 25,000 to 50,000 during the Great Depression.[49] Native carnivorans include black bears, bobcats, coyotes, both gray and red foxes, raccoons, and skunks. Rodents include groundhogs, weasels, nutria, beavers, both gray squirrels and fox squirrels, chipmunks, and Allegheny woodrats, while bats include brown bats and the Virginia big-eared bat, the state mammal.[50] The Virginia opossum is also the only marsupial native to the United States and Canada,[51] and the native Appalachian cottontail was recognized as a distinct species of rabbit in 1992.[52]
+
+Virginia's bird fauna, as of 1995, consists of some 422 species, of which 359 are regularly occurring, 41 are accidental (vagrant), 20 are hypothetical, and two are extinct; of the regularly occurring species, 214 have bred in Virginia, while the rest are winter residents or transients in Virginia.[53] There are no species of bird endemic to the state.[53] Audubon recognizes 21 Important Bird Areas in the Virginia.[54] Peregrine falcons, whose numbers dramatically declined due to DDT pesticide poisoning in the middle of the 20th century, are the focus of conservation efforts in the state; as of 2017, Virginia had 31 breeding pairs of the bird, and a reintroduction program in Shenandoah National Park was underway.[55]
+
+Virginia has 226 species of freshwater fish, from 25 families; the state's diverse array of fish species is attributable to its varied and humid climate, physiography, river system interconnections, and lack of Pleistocene glaciers. For example, the state is home to Eastern blacknose dace and sculpin (on the Appalachian Plateau); smallmouth bass and redhorse sucker (in the Ridge and Valley region); brook trout, rainbow trout, brown trout, and the Kanawha darter (in the Blue Ridge); stripeback darter and Roanoke Bass (in the Piedmont); and swampfish, bluespotted sunfish, and pirate perch (on the Coastal Plain).[56] The Chesapeake Bay is host to many species, including blue crabs, clams, oysters, rockfish, as well as the invasive blue catfish.[57] Running brooks with rocky bottoms are often inhabited by plentiful amounts of crayfish.[32] Amphibians found in Virginia include the Cumberland Plateau salamander and Eastern hellbender.[58]
+
+Virginia has 30 National Park Service units, such as Great Falls Park and the Appalachian Trail, and one national park, Shenandoah National Park.[59] Shenandoah was established in 1935 and encompasses the scenic Skyline Drive. Almost forty percent (79,579 acres or 322.04 km2) of the park's total 199,173 acres (806.02 km2) area has been designated as wilderness under the National Wilderness Preservation System.[60] Virginia also has 38 Virginia state parks, 3 undeveloped parks, and 63 natural areas, totaling 127,000 acres (51,000 ha), of which approximately 70,000 acres (28,000 ha) are in state parks.[61] All are managed by the Virginia Department of Conservation and Recreation except for Breaks Interstate Park.[62] which lies on the Virginia-Kentucky border and is one of only two inter-state parks in the United States.[63] There are 22 state forests and other state lands managed by the Virginia Department of Forestry, totaling 67,920 acres (27,490 ha).[64] The Chesapeake Bay is not a national park, but is protected by both state and federal legislation; the jointly run Chesapeake Bay Program which conducts restoration on the bay and its watershed. The Great Dismal Swamp National Wildlife Refuge extends into North Carolina, as does the Back Bay National Wildlife Refuge, which marks the beginning of the Outer Banks.[65]
+
+Virginia celebrated its quadricentennial year in 2007, marking 400 years since the establishment of the Jamestown Colony. The observances highlighted contributions from Native Americans, Africans, and Europeans, each of which had a significant part in shaping Virginia's history.[67][68] Warfare, including among these groups, has also had an important role. Virginia was a focal point in conflicts from the French and Indian War, the American Revolution and the Civil War, to the Cold War and the War on Terrorism.[69] Fictionalized stories about the early colony, in particular the story of Pocahontas and John Smith, first became popular in the period after the Revolutionary War, and together with other myths surrounding George Washington's childhood and plantation elite in the antebellum period became touchstones of Virginian and American culture and helped shape the state's historic politics and beliefs.[70][66]
+
+The first people are estimated to have arrived in Virginia over 12,000 years ago.[71] By 5,000 years ago more permanent settlements emerged, and farming began by 900 AD. By 1500, the Algonquian peoples had founded towns such as Werowocomoco in the Tidewater region, which they referred to as Tsenacommacah. The other major language groups in the area were the Siouan to the west, and the Iroquoians, who included the Nottoway and Meherrin, to the north and south. After 1570, the Algonquians consolidated under Chief Powhatan in response to threats from these other groups on their trade network.[72] Powhatan controlled more than 30 smaller tribes and more than 150 settlements, who shared a common Virginia Algonquian language. In 1607, the native Tidewater population was between 13,000 and 14,000.[73]
+
+Several European expeditions, including a group of Spanish Jesuits, explored the Chesapeake Bay during the 16th century.[74] In 1583, Queen Elizabeth I of England granted Walter Raleigh a charter to plant a colony north of Spanish Florida.[75] In 1584, Raleigh sent an expedition to the Atlantic coast of North America.[76] The name "Virginia" may have been suggested then by Raleigh or Elizabeth, perhaps noting her status as the "Virgin Queen", and may also be related to a native phrase, "Wingandacoa", or name, "Wingina".[77] Initially the name applied to the entire coastal region from South Carolina to Maine, plus the island of Bermuda.[78] The London Company was incorporated as a joint stock company by the proprietary Charter of 1606, which granted land rights to this area. The company financed the first permanent English settlement in the "New World", Jamestown. Named for King James I, it was founded in May 1607 by Christopher Newport.[79] In 1619, colonists took greater control with an elected legislature called the House of Burgesses. With the bankruptcy of the London Company in 1624, the settlement was taken into royal authority as an English crown colony.[80]
+
+Life in the colony was perilous, and many died during the Starving Time in 1609 and the Anglo-Powhatan Wars, including the Indian massacre of 1622, which fostered the colonists' negative view of all tribes.[81] By 1624, only 3,400 of the 6,000 early settlers had survived.[82] However, European demand for tobacco fueled the arrival of more settlers and servants.[83] The headright system tried to solve the labor shortage by providing colonists with land for each indentured servant they transported to Virginia.[84] African workers were first imported to Jamestown in 1619 initially under the rules of indentured servitude. The shift to a system of African slavery in Virginia was propelled by the legal cases of John Punch, who was sentenced to lifetime slavery in 1640 for attempting to escape his servitude, and of John Casor, who was claimed by Anthony Johnson as his servant for life in 1655.[85] Slavery first appears in Virginia statutes in 1661 and 1662, when a law made it hereditary based on the mother's status.[86]
+
+Tensions and the geographic differences between the working and ruling classes led to Bacon's Rebellion in 1676, by which time current and former indentured servants made up as much as eighty percent of the population.[87] Rebels, largely from the colony's frontier, were also opposed to the conciliatory policy towards native tribes, and one result of the rebellion was the signing at Middle Plantation of the Treaty of 1677, which made the signatory tribes tributary states and was part of a pattern of appropriating tribal land by force and treaty. Middle Plantation saw the founding of The College of William & Mary in 1693 and was renamed Williamsburg as it became the colonial capital in 1699.[88] In 1747, a group of Virginian speculators formed the Ohio Company, with the backing of the British crown, to start English settlement and trade in the Ohio Country west of the Appalachian Mountains.[89] France, which claimed this area as part of their colony of New France, viewed this as a threat, and the ensuing French and Indian War became part of the Seven Years' War (1756–1763). A militia from several British colonies, called the Virginia Regiment, was led by then-Lieutenant Colonel George Washington.[90]
+
+The British Parliament's efforts to levy new taxes following the French and Indian War were deeply unpopular in the colonies. In the House of Burgesses, opposition to taxation without representation was led by Patrick Henry and Richard Henry Lee, among others.[91] Virginians began to coordinate their actions with other colonies in 1773, and sent delegates to the Continental Congress the following year.[92] After the House of Burgesses was dissolved by the royal governor in 1774, Virginia's revolutionary leaders continued to govern via the Virginia Conventions. On May 15, 1776, the Convention declared Virginia's independence from the British Empire and adopted George Mason's Virginia Declaration of Rights, which was then included in a new constitution.[93] Another Virginian, Thomas Jefferson, drew upon Mason's work in drafting the national Declaration of Independence.[94]
+
+When the American Revolutionary War began, George Washington was selected to head the colonial army. During the war, the capital was moved to Richmond at the urging of Governor Thomas Jefferson, who feared that Williamsburg's coastal location would make it vulnerable to British attack.[95] In 1781, the combined action of Continental and French land and naval forces trapped the British army on the Virginia Peninsula, where troops under George Washington and Comte de Rochambeau defeated British General Cornwallis in the Siege of Yorktown. His surrender on October 19, 1781 led to peace negotiations in Paris and secured the independence of the colonies.[96]
+
+Virginians were instrumental in writing the United States Constitution. James Madison drafted the Virginia Plan in 1787 and the Bill of Rights in 1789.[94] Virginia ratified the Constitution on June 25, 1788. The three-fifths compromise ensured that Virginia, with its large number of slaves, initially had the largest bloc in the House of Representatives. Together with the Virginia dynasty of presidents, this gave the Commonwealth national importance. In 1790, both Virginia and Maryland ceded territory to form the new District of Columbia, though the Virginian area was retroceded in 1846.[97] Virginia is called the "Mother of States" because of its role in being carved into states such as Kentucky, which became the 15th state in 1792, and for the numbers of American pioneers born in Virginia.[98]
+
+In addition to agriculture, slave labor was increasingly used in mining, shipbuilding and other industries.[99] The execution of Gabriel Prosser in 1800, Nat Turner's slave rebellion in 1831 and John Brown's Raid on Harpers Ferry in 1859 marked the growing social discontent over slavery and its role in the plantation economy. By 1860, almost half a million people, roughly 31 percent of the total population of Virginia, were enslaved.[100] This division contributed to the start of the American Civil War.
+
+Virginia voted to secede from the United States on April 17, 1861, after the Battle of Fort Sumter and Abraham Lincoln's call for volunteers. On April 24, Virginia joined the Confederate States of America, which chose Richmond as its capital.[98] After the 1861 Wheeling Convention, 48 counties in the northwest separated to form a new state of West Virginia, which chose to remain loyal to the Union. Virginian general Robert E. Lee took command of the Army of Northern Virginia in 1862, and led invasions into Union territory, ultimately becoming commander of all Confederate forces. During the war, more battles were fought in Virginia than anywhere else, including Bull Run, the Seven Days Battles, Chancellorsville, and the concluding Battle of Appomattox Court House.[101] After the capture of Richmond in April 1865, the state capital was briefly moved to Lynchburg,[102] while the Confederate leadership fled to Danville.[103] Virginia was formally restored to the United States in 1870, due to the work of the Committee of Nine.[104]
+
+During the post-war Reconstruction era, Virginia adopted a constitution which provided for free public schools, and guaranteed political, civil, and voting rights.[105] The populist Readjuster Party ran an inclusive coalition until the conservative white Democratic Party gained power after 1883.[106] It passed segregationist Jim Crow laws and in 1902 rewrote the Constitution of Virginia to include a poll tax and other voter registration measures that effectively disenfranchised most African Americans and many poor European Americans.[107] Though their schools and public services were segregated and underfunded due to a lack of political representation, African Americans were able to unite in communities and take a greater role in Virginia society.[108]
+
+New economic forces also changed the Commonwealth. Virginian James Albert Bonsack invented the tobacco cigarette rolling machine in 1880 leading to new industrial scale production centered around Richmond. In 1886, railroad magnate Collis Potter Huntington founded Newport News Shipbuilding, which was responsible for building six World War I-era dreadnoughts, seven battleships, and 25 destroyers for the U.S. Navy from 1907 to 1923.[109] During the war, German submarines like U-151 attacked ships outside the port.[110] In 1926, Dr. W.A.R. Goodwin, rector of Williamsburg's Bruton Parish Church, began restoration of colonial-era buildings in the historic district with financial backing of John D. Rockefeller, Jr.[111] Though their project, like others in the state, had to contend with the Great Depression and World War II, work continued as Colonial Williamsburg became a major tourist attraction.[112]
+
+Protests started by Barbara Rose Johns in 1951 in Farmville against segregated schools led to the lawsuit Davis v. County School Board of Prince Edward County. This case, filed by Richmond natives Spottswood Robinson and Oliver Hill, was decided in 1954 with Brown v. Board of Education, which rejected the segregationist doctrine of "separate but equal". But, in 1958, under the policy of "massive resistance" led by the influential segregationist Senator Harry F. Byrd and his Byrd Organization, the Commonwealth prohibited desegregated local schools from receiving state funding.[113]
+
+The civil rights movement gained many participants in the 1960s. It achieved the moral force and support to gain passage of national legislation with the Civil Rights Act of 1964 and the Voting Rights Act of 1965. In 1964 the United States Supreme Court ordered Prince Edward County and others to integrate schools.[114] In 1967, the Court also struck down the state's ban on interracial marriage with Loving v. Virginia. From 1969 to 1971, state legislators under Governor Mills Godwin rewrote the constitution, after goals such as the repeal of Jim Crow laws had been achieved. In 1989, Douglas Wilder became the first African American elected as governor in the United States.[115]
+
+The Cold War led to the expansion of national defense government programs housed in offices in Northern Virginia near Washington, D.C., and correlative population growth.[116] The Central Intelligence Agency in Langley was involved in various Cold War events, including as the target of Soviet espionage activities. Also among the federal developments was the Pentagon, built during World War II as the headquarters for the Department of Defense. It was one of the targets of the September 11 attacks; 189 people died at the site when a jet passenger plane was flown into the building.[117] Mass shootings at Virginia Tech in 2007 and in Virginia Beach in 2019 led to passage of gun control measures in 2020.[118] Racial injustice and the presence of Confederate monuments in Virginia have also led to large demonstrations, including in August 2017, when a white supremacist drove his car into protesters, killing one, and in June 2020, when protests that were part of the larger Black Lives Matter movement brought about the removal of statues on Monument Avenue in Richmond and elsewhere.[119]
+
+Virginia is divided into 95 counties and 38 independent cities, the latter acting in many ways as county-equivalents.[120] This general method of treating cities and counties on par with each other is unique to Virginia; only three other independent cities exist elsewhere in the United States, each in a different state.[121] Virginia limits the authority of cities and counties to countermand laws expressly allowed by the Virginia General Assembly under what is known as Dillon's Rule.[122] In addition to independent cities, there are also incorporated towns which operate under their own governments, but are part of a county. Finally there are hundreds of unincorporated communities within the counties. Virginia does not have any further political subdivisions, such as villages or townships.
+
+Over 3.1 million people, 36 percent of Virginians, live in Northern Virginia, which is part of the larger Washington metropolitan area and the Northeast megalopolis.[123] Fairfax County is the most populous locality in the state, with more than 1.1 million residents, although that does not include its county seat Fairfax City, which is one of the independent cities.[124] Fairfax County has a major urban business and shopping center in Tysons Corner, Virginia's largest office market.[125] Neighboring Prince William County is Virginia's second most populous county, with a population exceeding 450,000, and is home to Marine Corps Base Quantico, the FBI Academy and Manassas National Battlefield Park. Loudoun County, with the county seat at Leesburg, is the fastest-growing county in the state.[124][126] Arlington County, the smallest self-governing county in the United States by land area, is an urban community organized as a county.[127]
+
+Richmond is the capital of Virginia, and its metropolitan area has a population over 1.2 million.[128] As of 2019[update], Virginia Beach is the most populous independent city in the Commonwealth, with Chesapeake and Norfolk second and third, respectively.[129] The three are part of the larger Hampton Roads metropolitan area, which has a population over 1.7 million people and is the site of the world's largest naval base, Naval Station Norfolk.[128][130] Suffolk, which includes a portion of the Great Dismal Swamp, is the largest city by area at 429.1 square miles (1,111 km2).[131] In western Virginia, Roanoke city and Montgomery County, part of the Blacksburg–Christiansburg metropolitan area, both have surpassed a population of over 100,000 since 2018.[132]
+
+The United States Census Bureau estimates that the state population was 8,535,519 on July 1, 2019, a 6.7 percent increase since the 2010 United States Census.[6] This includes an increase of 534,495 people into the Commonwealth since the 2010 census. Immigration from outside the United States resulted in a net increase of 159,627 people, and migration within the country produced a net increase of 155,205 people.[135] As of 2010[update], the center of population was located in Louisa County, near Richmond.[136]
+
+Aside from Virginia, the top birth state for Virginians is New York, having overtaken North Carolina in the 1990s, with the Northeast accounting for the largest number of migrants into the state by region.[137] The median age in 2018 was 38.4 years old, making the state just slightly older than the national average of 38.2.[138]
+
+The state's most populous ethnic group, Non-Hispanic whites, has declined as a proportion of population from 76 percent in 1990 to 61 percent in 2019, as other ethnicities have increased.[139][6] People of English heritage settled throughout the Commonwealth during the colonial period, and others of British and Irish heritage have since immigrated.[140] Those who identify on the census as having "American ethnicity" are predominantly of English descent, but have ancestors who have been in North America for so long they choose to identify simply as American.[141][142] Of the English immigrants to Virginia in the 17th century, three-fourths came as indentured servants.[143] The western mountains have many settlements that were founded by Scots-Irish immigrants before the American Revolution.[144][145] There are also sizable numbers of people of German descent in the northwestern mountains and Shenandoah Valley.[146] On the 2018 American Community Survey, eleven percent said they were of German ancestry.[147]
+
+The largest minority group in Virginia are African Americans, who include about one-fifth of the population.[6] Virginia was a major destination of the Atlantic slave trade, and the first generations of enslaved men, women and children were brought primarily from Angola and the Bight of Biafra. The Igbo ethnic group of what is now southern Nigeria were the single largest African group among slaves in Virginia.[148] Many African Americans also have European and Native American ancestry, often with asymmetrical male and female ancestry contribution.[149] Though the Black population was reduced by the Great Migration to northern industrial cities in the first half of the 20th century, since 1965 there has been a reverse migration of Blacks returning south.[150] According to the Pew Research Center, the state has the highest number of black-white interracial marriages in the United States,[151] and 3.1 percent of Virginians describe themselves as biracial.[6]
+
+More recent immigration in the late 20th century and early 21st century has resulted in new communities of Hispanics and Asians. Among international immigrants to Virginia, eleven percent were born in El Salvador, nine percent in India, six percent in South Korea and five percent each in Mexico and the Philippines, and 52 percent are U.S. citizens as of 2017[update].[152] As of 2019[update], 9.6 percent of Virginia's total population describe themselves as Hispanic or Latino, and 6.9 percent as Asian.[6] The state's Hispanic population rose by 92 percent from 2000 to 2010, with two-thirds of Hispanics in the state living in Northern Virginia.[153] Hispanic citizens in Virginia have higher median household incomes and educational attainment than the general state population.[154] Northern Virginia also has a significant population of Vietnamese Americans, whose major wave of immigration followed the Vietnam War.[155] Korean Americans have migrated more recently, attracted by the quality school system.[156] The Filipino American community has about 45,000 in the Hampton Roads area, many of whom have ties to the U.S. Navy and armed forces.[157]
+
+Additionally, 0.5 percent of Virginians are American Indian or Alaska Native, and 0.1 percent are Native Hawaiian or other Pacific Islander.[6] Virginia has extended state recognition to eleven Native American tribes resident in the state. Seven tribes also have federal recognition, including six that were recognized in 2018 after passage of bill named for activist Thomasina Jordan.[158][159] The Pamunkey and Mattaponi have reservations on tributaries of the York River in the Tidewater region.[160]
+
+American Community Survey five-year estimate
+
+As of 2010[update], 85.9% (6,299,127) of Virginia residents age five and older spoke English at home as a first language, while 14.1% (1,036,442) did not—6.4% (470,058) spoke Spanish, 0.8% (56,518) Korean, 0.6% (45,881) Vietnamese, 0.6% (42,418) Chinese (including Mandarin), and 0.6% (40,724) Tagalog.[161] English was passed as the Commonwealth's official language by statutes in 1981 and again in 1996, though the status is not mandated by the Constitution of Virginia.[162]
+
+The Piedmont region is known for its dialect's strong influence on Southern American English. While a more homogenized American English is found in urban areas, various accents are also used, including the Tidewater accent, the Old Virginia accent, and the anachronistic Elizabethan of Tangier Island.[163][164]
+
+Virginia is predominantly Christian and Protestant; Baptist denominations combined to form largest group with about 26 percent of the population as of 2014[update],[165] and around 763,655 total members as of 2010[update].[166] Baptist denominational groups in Virginia include the Baptist General Association of Virginia, with about 1,400 member churches, which supports both the Southern Baptist Convention and the moderate Cooperative Baptist Fellowship; and the Southern Baptist Conservatives of Virginia with more than 500 affiliated churches, which supports the Southern Baptist Convention.[167][168] Roman Catholics are the second-largest religious group with 673,853 members.[166] The Roman Catholic Diocese of Arlington includes most of Northern Virginia's Catholic churches, while the Diocese of Richmond covers the rest.
+
+The Virginia Conference is the regional body of the United Methodist Church in most of the Commonwealth, while the Holston Conference represents much of extreme Southwest Virginia. The Virginia Synod is responsible for the congregations of the Lutheran Church. Presbyterian, Pentecostal, Congregationalist, and Episcopalian adherents each comprised less than two percent of the population as of 2010[update].[166] The Episcopal Diocese of Virginia, Southern Virginia, and Southwestern Virginia support the various Episcopal churches.
+
+In November 2006, 15 conservative Episcopal churches voted to split from the Diocese of Virginia over the ordination of openly gay bishops and clergy in other dioceses of the Episcopal Church; these churches continue to claim affiliation with the larger Anglican Communion through other bodies outside the United States. Though Virginia law allows parishioners to determine their church's affiliation, the diocese claimed the secessionist churches' buildings and properties. The resulting property law case, ultimately decided in favor of the mainline diocese, was a test for Episcopal churches nationwide.[169]
+
+Among other religions, adherents of The Church of Jesus Christ of Latter-day Saints constitute one percent of the population, with two hundred congregations in Virginia as of 2017[update].[170] Fairfax Station is the site of the Ekoji Buddhist Temple, of the Jodo Shinshu school, and the Hindu Durga Temple. While the state's Jewish population is small, organized Jewish sites date to 1789 with Congregation Beth Ahabah.[171] Muslims are a growing religious group throughout the Commonwealth through immigration.[172] Megachurches in the Commonwealth include Thomas Road Baptist Church, Immanuel Bible Church, and McLean Bible Church.[173] Several Christian universities are also based in the state, including Regent University, Liberty University, and the University of Lynchburg.
+
+Virginia's economy has diverse sources of income, including local and federal government, military, farming and high-tech. Prior to the coronavirus recession, Virginia had 4.36 million people employed with an unemployment rate of 2.9 percent in March 2020,[174] but jobless claims due to the virus peaked in early April 2020, before falling slightly in May, when the state had 386,000 unemployed with a rate of 9.4 percent,[175] which was tied for the 11th-lowest nationwide.[176] The state's average earnings per job was $63,281, the 11th-highest nationwide,[177] and the gross domestic product (GDP) was $476.4 billion in 2018, the 13th-largest among U.S. states.[178] Canada is the state's leading international market, receiving 17.2 percent of exports.[179]
+
+Virginia has a median household income of $72,600, 11th-highest nationwide, and a poverty rate of 10.7 percent, 12th-lowest nationwide, as of 2018[update]. Montgomery County outside Blacksburg has the highest poverty rate in the state, with 28.5 percent falling below the U.S. Census poverty thresholds. Loudoun County meanwhile has the highest median household income in the nation, and the wider Northern Virginia region is among the highest-income regions nationwide.[180] As of 2013[update], six of the twenty highest-income counties in the United States, including the two highest,[181] as well as three of the fifty highest-income towns, are all located in Northern Virginia.[182] Though the Gini index shows Virginia has less income inequality than the national average,[183] the state's middle class is also smaller than the majority of states.[184]
+
+Virginia has the highest defense spending of any state per capita, providing the Commonwealth with around 900,000 jobs.[186][187] Approximately twelve percent of all U.S. federal procurement money is spent in Virginia, the second-highest amount after California.[187][188] Many Virginians work for federal agencies in Northern Virginia, which include the Central Intelligence Agency and the Department of Defense, as well as the National Science Foundation, the United States Geological Survey and the United States Patent and Trademark Office. Many others work for government contractors, including defense and security firms, which hold more than 15,000 federal contracts.[189]
+
+Virginia has one of the highest concentrations of veterans of any state,[190] and is second to California in total Department of Defense employees.[188][191] The Hampton Roads area has the largest concentration of military personnel and assets of any metropolitan area in the world,[192] including the largest naval base in the world, Naval Station Norfolk.[130] In its state government, Virginia employs 106,143 public employees, who combined have a median income of $44,656 as of 2013[update].[193]
+
+Virginia was home to 653,193 separate firms in the 2012 U.S. Census Survey of Business Owners, with 54% of those majority male-owned and 36.2% majority female-owned. Approximately 28.3% of firms were also majority minority-owned, and 11.7% were veteran-owned.[194] Twenty-one Fortune 500 companies are headquartered in Virginia as of 2019[update], with the largest companies by revenue being Freddie Mac, General Dynamics, and Capital One.[195] The largest by their number of employees are Dollar Tree in Chesapeake and Hilton Worldwide Holdings in McLean.[196]
+
+Virginia's business environment has been ranked highly by various publications. In 2019, CNBC named Virginia their Top State for Business, with its deductions being mainly for the high cost of living,[197] while Forbes magazine ranked it fourth, though number one in quality of life.[198] Additionally, in 2014 a survey of 12,000 small business owners found Virginia to be one of the most friendly states for small businesses.[199] Oxfam America however ranked Virginia last in their July 2018 ranking of best states to work in, largely due to a low minimum wage of $7.25, and the state's organized labor laws. Though the topic was debated during in the 2019–20 General Assembly session, Virginia has been a "right to work" state since 1947,[200] and an employment-at-will state since 1906.[201]
+
+Virginia has the highest concentration of technology workers of any state,[202] and the fourth-highest number of technology workers after California, Texas, and New York.[203] Computer chips became the state's highest-grossing export in 2006,[204] with a total export value of $694 million in 2019.[179] Northern Virginia, once considered the state's dairy capital, now hosts software, communication technology, defense contracting companies, particularly in the Dulles Technology Corridor and Tysons Corner areas. The state has the highest average and peak Internet speeds in the United States, with the third-highest worldwide.[205] Northern Virginia's data centers can carry up to seventy percent of the nation's Internet traffic,[206] and in 2015 the region was the largest and fastest growing data center market in the nation.[207][208]
+
+Tourism in Virginia supported an estimated 234,000 jobs in 2018, making tourism the state's fifth largest industry. It generated $26 billion, an increase 4.4 percent from 2017.[209] The state was eighth nationwide in domestic travel spending in 2018, with Arlington County the top tourist destination in the state by domestic spending, followed by Fairfax County, Loudoun County, and Virginia Beach.[210] Virginia also saw 1.1 million international tourists in 2018, a five percent increase from 2017.[211]
+
+As of 2017[update], agriculture occupied 28 percent of the land in Virginia with 7.8 million acres (12,188 sq mi; 31,565 km2) of farmland. Nearly 54,000 Virginians work on the state's 43,225 farms, which average 181 acres (0.28 sq mi; 0.73 km2). Though agriculture has declined significantly since 1960 when there were twice as many farms, it remains the largest single industry in Virginia, providing for over 334,000 jobs.[213] Soybeans were the most profitable crop in Virginia in 2017, ahead of corn and cut flowers as other leading agricultural products.[214] However, the ongoing China-U.S. trade war led many Virginia farmers to plant cotton instead of soybeans in 2019.[215] Though it is no longer the primary crop, Virginia is still the third-largest producer of tobacco in the United States.[213]
+
+Virginia is also the country's third-largest producer of seafood as of 2018[update], with sea scallops, oysters, Chesapeake blue crabs, menhaden, and hardshell clams as the largest seafood harvests by value, and France, Canada, and Hong Kong as the top export destinations.[216][217] Commercial fishing supports 18,220 jobs as of 2020[update], while recreation fishing supports another 5,893.[218] Eastern oyster harvests had increased from 23,000 bushels in 2001 to over 500,000 in 2013,[219] but fell to 248,347 in 2019 because of low salinity in coastal waters due to heavy spring rains.[220] Those same rains however made 2019 a record wine harvest for vineyards in the Northern Neck and along the Blue Ridge Mountains, which also attract 2.3 million tourists annually.[221][222] Virginia has the seventh-highest number of wineries in the nation, with 307 as of January 2020[update].[223] Cabernet franc and Chardonnay are the most grown varieties.[224]
+
+Virginia collects personal income tax from those with incomes above a filing threshold; there are five income brackets, with rates ranging from 2.0% to 5.75% of taxable income.[225][226] The state sales and use tax rate is 4.3%. There is an additional 1% local tax, for a total of a 5.3% combined sales tax on most Virginia purchases. The sales tax rate is  higher in three regions: Northern Virginia (6%), Hampton Roads (6%) and the Historic Triangle (7%).[227] Unlike the majority of states, Virginia collects sales tax on groceries, but at a lower rate than the general sales tax;[228] the sales tax for food and certain essential personal hygiene goods is 2.5%.[227]
+
+Virginia's property tax is set and collected at the local government level and varies throughout the Commonwealth. Real estate is also taxed at the local level based on one hundred percent of fair market value.[229] As of fiscal year 2018, the median real estate tax rate per $100 of assessed taxable value was $1.07 for cities, $0.67 for counties, and $0.17 for towns; town rates are lower because towns (unlike cities) have a narrow range of responsibilities and are subordinate to counties.[230] Of local government tax revenue, about 61% is generated from real property taxes; about 24% from tangible personal property, sales and use, and business license tax; and 15% from other taxes (such as restaurant meal taxes, public service corporation property tax, consumer utility tax, and hotel tax).[231]
+
+Virginia's culture was popularized and spread across America and the South by figures such as George Washington, Thomas Jefferson, and Robert E. Lee. Their homes in Virginia represent the birthplace of America and the South.[232] Modern Virginia culture has many sources, and is part of the culture of the Southern United States.[233] The Smithsonian Institution divides Virginia into nine cultural regions.[234]
+
+Besides the general cuisine of the Southern United States, Virginia maintains its own particular traditions. Virginia wine is made in many parts of the commonwealth.[222] Smithfield ham, sometimes called "Virginia ham", is a type of country ham which is protected by state law, and can be produced only in the town of Smithfield.[235] Virginia furniture and architecture are typical of American colonial architecture. Thomas Jefferson and many of the commonwealth's early leaders favored the Neoclassical architecture style, leading to its use for important state buildings. The Pennsylvania Dutch and their style can also be found in parts of the commonwealth.[146]
+
+Literature in Virginia often deals with the commonwealth's extensive and sometimes troubled past. The works of Pulitzer Prize winner Ellen Glasgow often dealt with social inequalities and the role of women in her culture.[236] Glasgow's peer and close friend James Branch Cabell wrote extensively about the changing position of gentry in the Reconstruction era, and challenged its moral code with Jurgen, A Comedy of Justice.[237] William Styron approached history in works such as The Confessions of Nat Turner and Sophie's Choice.[238] Tom Wolfe has occasionally dealt with his southern heritage in bestsellers like I Am Charlotte Simmons.[239] Mount Vernon native Matt Bondurant received critical acclaim for his historic novel The Wettest County in the World about moonshiners in Franklin County during prohibition.[240] Virginia also names a state Poet Laureate.[241]
+
+Rich in cultural heritage, Virginia however ranks near the bottom of U.S. states in terms of public spending on the arts, at nearly half of the national average.[242] The state government does fund some institutions, including the Virginia Museum of Fine Arts and the Science Museum of Virginia. Other museums include the popular Steven F. Udvar-Hazy Center of the National Air and Space Museum and the Chrysler Museum of Art.[243] Besides these sites, many open-air museums are located in the Commonwealth, such as Colonial Williamsburg, the Frontier Culture Museum, and various historic battlefields.[244] The Virginia Foundation for the Humanities works to improve the Commonwealth's civic, cultural, and intellectual life.[245]
+
+Theaters and venues in the Commonwealth are found both in the cities and in suburbs. The Harrison Opera House, in Norfolk, is home of the Virginia Opera. The Virginia Symphony Orchestra operates in and around Hampton Roads.[246] Resident and touring theater troupes operate from the American Shakespeare Center in Staunton.[247] The Barter Theatre in Abingdon, designated the State Theatre of Virginia, won the first Regional Theatre Tony Award in 1948, while the Signature Theatre in Arlington won it in 2009. There is also a Children's Theater of Virginia, Theatre IV, which is the second largest touring troupe nationwide.[248] Notable music performance venues include The Birchmere, the Landmark Theater, and Jiffy Lube Live.[249] Wolf Trap National Park for the Performing Arts is located in Vienna and is the only national park intended for use as a performing arts center.[250]
+
+Virginia has launched many award-winning traditional musical artists and internationally successful popular music acts, as well as Hollywood actors.[1] Virginia is known for its tradition in the music genres of old-time string and bluegrass, with groups such as the Carter Family and Stanley Brothers.[251] The state's African tradition is found through gospel, blues, and shout bands, with both Ella Fitzgerald and Pearl Bailey coming from Newport News.[252] Contemporary Virginia is also known for folk rock artists like Dave Matthews and Jason Mraz, hip hop stars like Pharrell Williams, Missy Elliott and Pusha T, as well as thrash metal groups like GWAR and Lamb of God.[253] Several members of country music band Old Dominion grew up in the Roanoke area, and took their band name from Virginia's state nickname.[254]
+
+Many counties and localities host county fairs and festivals. The Virginia State Fair is held at the Meadow Event Park every September. Also in September is the Neptune Festival in Virginia Beach, which celebrates the city, the waterfront, and regional artists. Norfolk's Harborfest, in June, features boat racing and air shows.[255] Fairfax County also sponsors Celebrate Fairfax! with popular and traditional music performances.[256] The Virginia Lake Festival is held during the third weekend in July in Clarksville.[257] Wolf Trap hosts the Wolf Trap Opera Company, which produces an opera festival every summer.[250] Each September, Bay Days celebrates the Chesapeake Bay as well as Hampton's 400-year history since 1610, and Isle of Wight County holds a County Fair on the second week of September as well. Both feature live music performances, and other unique events.
+
+On the Eastern Shore island of Chincoteague the annual Pony Swim & Auction of feral Chincoteague ponies at the end of July is a unique local tradition expanded into a week-long carnival. The Shenandoah Apple Blossom Festival is a six-day festival held annually in Winchester which includes parades and bluegrass concerts. The Old Time Fiddlers' Convention in Galax, begun in 1935, is one of the oldest and largest such events worldwide. Two important film festivals, the Virginia Film Festival and the VCU French Film Festival, are held annually in Charlottesville and Richmond, respectively.[258]
+
+The Hampton Roads area is the 42nd-largest media market in the United States as ranked by Nielsen Media Research, while the Richmond-Petersburg area is 54th and Roanoke-Lynchburg is 69th as of 2020[update].[259] Northern Virginia is part of the much larger Washington, D.C. media market.
+
+There are 36 television stations in Virginia, representing each major U.S. network, part of 42 stations which serve Virginia viewers including those broadcasting from neighboring jurisdictions.[260] According the Federal Communications Commission, 595 FCC-licensed FM radio stations broadcast in Virginia, with 239 such AM stations as of 2020[update].[261][262] The nationally available Public Broadcasting Service (PBS) is headquartered in Arlington. Independent PBS affiliates exist throughout Virginia, and the Arlington PBS member station WETA-TV produces programs such as the PBS NewsHour and Washington Week.
+
+The most circulated native newspapers in the Commonwealth are Norfolk's The Virginian-Pilot with around 132,000 subscribers,[263] the Richmond Times-Dispatch with 86,219,[264] and The Roanoke Times as of 2018[update].[265] The paper with nation's most daily readers, USA Today, with 520,000 daily subscriptions, is headquartered in McLean.[266] USA Today is the flagship publication of Gannett, Inc., which merged with GateHouse Media in 2019, and operates over one hundred local newspapers nationwide.[267] In Northern Virginia, The Washington Post is the dominant newspaper and provides local coverage for the region.[268] Politico, which covers national politics, has its offices in Rosslyn.[269]
+
+Virginia's educational system consistently ranks in the top five states on the U.S. Department of Education's National Assessment of Educational Progress, with Virginia students outperforming the average in all subject areas and grade levels tested.[270] The 2019 Quality Counts report ranked Virginia's K–12 education third in the country, with a letter grade of B.[271][272] All school divisions must adhere to educational standards set forth by the Virginia Department of Education, which maintains an assessment and accreditation regime known as the Standards of Learning to ensure accountability.[273]
+
+Public K–12 schools in Virginia are generally operated by the counties and cities, and not by the state. As off the 2018–19 academic year,[update] a total of 1,290,576 students were enrolled in 2,293 local and regional schools in the Commonwealth, including eight charter schools, and an additional 98 alternative and special education centers across 133 school divisions.[274][275] 2018 marked the first decline in overall enrollment in public schools, by just over 2,000 students, since 1984.[276] Besides the general public schools in Virginia, there are Governor's Schools and selective magnet schools. The Governor's Schools are a collection of more than 40 regional high schools and summer programs intended for gifted students.[277] The Virginia Council for Private Education oversees the regulation of 483 state accredited private schools.[278] An additional 17,283 students receive homeschooling.[279]
+
+In 2019, 91.5 percent of high school students graduated on-time after four years,[280] an increase of two percent from 2013,[281] and 89.3 percent of adults over the age 25 had their high school diploma.[6] Virginia has one of the smaller racial gaps in graduation rates among U.S. states,[282] with 89.7 percent of Black students graduating on time, compared to 94.7 percent  of white students and 97.5 percent of Asian students.[280] Despite ending school segregation in the 1960s, seven percent of Virginia's public schools were rated as "intensely segregated" by The Civil Rights Project at UCLA in 2019, and the number has risen since 1989, when only three percent were.[283] Virginia has comparatively large public school districts, typically comprising entire counties or cites, and this helps mitigate funding gaps seen in other states such that non-white districts average slightly more funding, $255 per student as of 2019[update], than majority white districts.[284]
+
+As of 2019[update], Virginia has the sixth highest percent of residents with bachelors degrees or higher, with 38.2 percent.[6] As of that year, there are 169 colleges and universities in Virginia.[286] In the 2019 U.S. News & World Report ranking of national public universities, the University of Virginia is ranked No. 3, the College of William and Mary is No. 10, Virginia Tech is No. 30, George Mason University is No. 67, and Virginia Commonwealth University is No. 80.[287] James Madison University is ranked the No. 6 regional university in The South.[288] There are 124 private institutions in the state, including nationally ranked liberal arts colleges Washington and Lee University at No. 11, the University of Richmond at No. 25, and the Virginia Military Institute at No. 81.[286][289]
+
+Virginia Tech and Virginia State University are the state's land-grant universities. The Virginia Military Institute is the oldest state military college.[290] Virginia also operates 23 community colleges on 40 campuses which enrolled more than 228,000 degree-seeking students during the 2018–2019 school year.[291] As of 2019[update], George Mason University had the largest on-campus enrollment at 37,677 students,[292] though the private Liberty University had the largest total enrollment in the state, with 88,283 online and 15,105 on-campus students in Lynchburg.[293]
+
+Virginia has a mixed health record, and was ranked as the 15th overall healthiest state according to the 2019 United Health Foundation's Health Rankings. Virginia was 19th lowest among U.S. states in its number of premature deaths, with 6,914 per 100,000, and 24th with an infant mortality rate of 5.9 per 1,000 live births.[42] There are however racial and social health disparities. With high rates of heart disease and diabetes, African Americans in Virginia had an average life expectancy 4 years lower than whites and 12 years lower than Asian Americans and Latinos in 2017,[296] and were disproportionately affected by COVID-19 during the coronavirus pandemic.[297] African-American mothers are also three times more likely to die while giving birth in the state.[298] Mortality rates among white middle-class Virginians have also been rising, with drug overdose, suicide, and alcohol poisoning as leading causes.[299]
+
+Weight is an issue for many Virginians, and 30.3% of adults and 13.2% of 10- to 17-year-olds are obese as of 2019[update].[42][300] Additionally, 35% of adults are overweight and 23.3% do not exercise regularly.[301] Virginia banned smoking in bars and restaurants in January 2010,[302] and the percent of tobacco smokers in the state has declined from 19% in that year to 14.9% in 2019. Virginia does have among the highest rates of immunization nationwide, ranking 6th for childhood immunization and 14th for both TDaP and HPV vaccines per capita.[42] Virginia was the first U.S. state to mandate HPV vaccination for girls for school attendance, which it did in 2008.[303]
+
+There are 90 hospitals in Virginia with a combined 17,706 hospital beds as of 2020[update].[304] Notable examples include Inova Fairfax Hospital, the largest hospital in the Washington Metropolitan Area, and the VCU Medical Center, located on the medical campus of Virginia Commonwealth University. The University of Virginia Medical Center, part of the University of Virginia Health System, is highly ranked in endocrinology according to U.S. News & World Report.[305] Virginia has a ratio of 148.1 primary care physicians per 10,000 residents, which is the 24th highest nationally, but only 171.9 mental health providers per that number, the 10th lowest nationwide. The rate of uninsured Virginians dropped to 8.8% after the state government passed Medicare expansion in 2019.[42]
+
+Because of the 1932 Byrd Road Act, the state government controls most of Virginia's roads, instead of a local county authority as is usual in other states.[307] As of 2018[update], the Virginia Department of Transportation owns and operates 57,867 miles (93,128 km) of the total 70,105 miles (112,823 km) of roads in the state, making it the third largest state highway system in the United States.[308] Although the Washington Metropolitan Area, which includes Northern Virginia, has the second highest rate of traffic congestion in the nation, Virginia as a whole has the 21st-lowest rate of congestion and the average commute time is 26.9 minutes.[309][310] Virginia hit peak car usage before the year 2000, making it one of the first such states.[311]
+
+Virginia has Amtrak passenger rail service along several corridors, and Virginia Railway Express (VRE) maintains two commuter lines into Washington, D.C. from Fredericksburg and Manassas. VRE is one of the nation's fastest growing commuter rail services, handling nearly 20,000 passengers a day.[312] Arlington accounted for forty percent of Virginia's public transit trips as of 2013[update], with most of that being from the Washington Metro transit system, which also serves Alexandria and communities in Fairfax County along I-66.[313] The system is currently expanding west into additional areas of Loudoun County.[314] Major freight railroads in Virginia include Norfolk Southern and CSX Transportation. Commuter buses include the Fairfax Connector, FRED buses in Fredericksburg, and OmniRide in Prince William County.[315] The Virginia Department of Transportation operates several free ferries throughout Virginia, the most notable being the Jamestown Ferry which connects Jamestown to Scotland Wharf across the James River.[316]
+
+Virginia has five major airports: Washington Dulles International and Reagan Washington National in Northern Virginia, both of which handle more than twenty million passengers a year; Richmond International; and Newport News/Williamsburg International Airport and Norfolk International serving the Hampton Roads area. Several other airports offer limited commercial passenger service, and sixty-six public airports serve the state's aviation needs.[317] The Virginia Port Authority's main seaports are those in Hampton Roads, which carried 69,416,600 short tons (62,973,700 t) of total cargo in 2018[update], the fifth most of United States ports.[318] The Eastern Shore of Virginia is the site of Wallops Flight Facility, a rocket testing center owned by NASA, and the Mid-Atlantic Regional Spaceport, a commercial spaceport.[319][320] Space tourism is also offered through Vienna-based Space Adventures.[321]
+
+In 1619, the first Virginia General Assembly met at Jamestown Church, and included 22 locally elected representatives, making Virginia's legislature the oldest in the North America.[8] These representatives became a formal House of Burgesses in 1642 and governed with the crown-appointed Governor's Council until Virginia declared independence in 1776. The current General Assembly is the 161st since that year. The government today functions under the seventh Constitution of Virginia, which was approved by voters in 1971 and is similar to the federal structure in that it provides for three branches: a strong legislature, an executive, and a unified judicial system.[322]
+
+Virginia's legislature is bicameral with a 100-member House of Delegates and 40-member Senate, who together write the laws for the Commonwealth. Delegates serve two-year terms, while senators serve four-year terms, with the most recent elections for both taking place in November 2019. The legislature meets annually starting on the second Wednesday of the year, typically for 60 days in even years and 48 days in odd years due to the state's biannual budgeting, though special sessions can be called either by the governor or with agreement of two-thirds of both houses.[323] Special sessions are common, and have been called in 2019 and 2020 for topics such as gun control, the impact of the coronavirus on the state budget, and police reform.[324][325]
+
+The executive department includes the governor and lieutenant governor, who are elected every four years in separate elections, with the next taking place in November 2021. The governor must be at least 30 years old and incumbent governors cannot run for re-election, however the lieutenant governor and attorney general can, and governors can and have served non-consecutive terms.[322] The lieutenant governor is the official head of the Senate, and is responsible for breaking ties. The House elects a Speaker of the House and the Senate elects a President pro tempore, who presides when the lieutenant governor isn't present, and both houses elect a clerk and majority and minority leaders.[323] State budgets are proposed in even years by the governor.[326] Based on data through 2018, the Pew Center on the States found the state government to be above average in running surpluses,[327] while U.S. News and World Report ranked the state eighth in fiscal stability.[328]
+
+The judges and justices who make up Virginia's judicial system, also the oldest in America, are elected by a majority vote in both the House and Senate without input from the governor, one way Virginia's legislature is stronger than its executive. The system consists of a hierarchy from the Supreme Court of Virginia and the Court of Appeals of Virginia to the Circuit Courts, the trial courts of general jurisdiction, and the lower General District Courts and Juvenile and Domestic Relations District Courts.[329] The Supreme Court has seven justices who serve twelve-year terms, with a mandatory retirement age of 73. The Supreme Court selects its own Chief Justice from among their seven members, who is informally limited to two four-year terms.[330]
+
+The Code of Virginia is the statutory law, and consists of the codified legislation of the General Assembly. The Virginia State Police is the largest law enforcement agency in Virginia. The Virginia Capitol Police is the oldest police department in the United States.[331] The Virginia National Guard consists of 7,500 soldiers in the Virginia Army National Guard and 1,200 airmen in the Virginia Air National Guard.[332] Since the resumption of capital punishment in Virginia in 1982, 113 people have been executed, the second highest number in the nation, and three inmates are on the state's death row as of 2019[update].[333] Virginia has the fourth lowest violent crime rate and 13th-lowest property crime rate as of 2018[update] according to FBI data.[334] Since Virginia ended prisoner parole in 1995, the rate of recidivism has fallen to 23.4 percent in 2019, the lowest nationwide.[335]
+
+Over the 20th century, Virginia shifted from a largely rural, politically Southern and conservative state to a more urbanized, pluralistic, and politically moderate environment. Up until the 1970s, Virginia was a racially divided one-party state dominated by the Byrd Organization,[337] which sought to stymie the political power of Northern Virginia, perpetuate segregation, and restrict voter registration.[338] The organization used  malapportionment to control what areas of the state were over-represented in the General Assembly and the U.S. Congress until ordered to end the practice by the 1964 U.S. Supreme Court decision in Davis v. Mann and the 1965 the Virginia Supreme Court decision in Wilkins v. Davis respectively.[339]
+
+Passage of Federal civil rights legislation in the mid-1960s, including the Voting Rights Act of 1965, helped end the state's Jim Crow laws which effectively disfranchised African Americans.[340] Greater enfranchisement and demographic shifts further changed the electorate. In 1980, 56 percent of eligible voters were born in the state; in 2019 that number was 45 percent, a result of strong international immigration and domestic migration into the state.[341]
+
+Regional differences also play a large part in Virginia politics.[342] While urban and growing suburban areas, including much of Northern Virginia, form the Democratic Party base, rural southern and western areas moved to support the Republican Party in response to its "southern strategy".[343][344] Rural Democratic support has nevertheless persisted in union-influenced Roanoke in Southwest Virginia, college towns such as Charlottesville and Blacksburg, and the southeastern Black Belt Region.[345] State election seasons traditionally start with the annual Shad Planking event in Wakefield.[336]
+
+State elections in Virginia occur in odd-numbered years, with executive department elections occurring in years following U.S. presidential elections and Senate elections occurring in the years prior to presidential elections, as both have four-year terms. House of Delegates elections take place concurrent with each of those elections as members have two-year terms. National politics often play a role in state election outcomes, and Virginia has elected governors of the party opposite the U.S. president in ten of the last eleven contests, with only Terry McAuliffe beating the trend.[346][347]
+
+McAuliffe, a Democrat, was elected Governor in the 2013 elections by two percentage points during Barack Obama's second presidential term.[348] Republicans, however, held a super-majority (68–32) of seats in the House of Delegates, which they had first gained in the 2011 state elections.[349] Republicans also held a one-vote majority the state senate, which they then maintained in the 2015 election.[350] Eleven house district lines used in these elections, drawn following the 2010 U.S. Census, were later judged unconstitutional for discriminating against African Americans.[351]
+
+The 2017 statewide elections resulted in Democrats holding the three highest offices, with outgoing lieutenant governor Ralph Northam winning the governorship, Justin Fairfax elected lieutenant governor, and Mark Herring continuing as attorney general. In concurrent House of Delegates elections, Democrats flipped fifteen of the Republicans' previous sixteen-seat majority.[352] Control of the House came down to the tied election in the 94th district, which was won by Republicans through drawing of lots, giving the party a slim 51–49 majority in the 2018–19 legislative sessions.[353] Despite a political crisis that February, Democrats took full control of the General Assembly in the November 2019 elections,[354] the first after several districts were redrawn because of discrimination.[355]
+
+In federal elections since 2006, both parties have seen successes. Republican Senator George Allen lost close races in 2006, to Democratic newcomer Jim Webb, and again in 2012, to Webb's replacement, former Governor Tim Kaine.[356] In 2008, Democrats won both United States Senate seats; former Governor Mark Warner was elected to replace retiring Republican John Warner.[357] In the 2010 mid-term elections, the first under President Obama, Republicans flipped three United States House of Representatives seats from the Democrats, while in the 2018 mid-terms, the first under President Trump, Democrats flipped three seats from Republicans. Of the state's eleven seats in the House of Representatives, Democrats currently hold seven and Republicans hold four.
+
+Though Virginia was considered a "swing state" in recent presidential elections,[7] Democrat Barack Obama carried Virginia's 13 electoral votes in 2008 and 2012,[358] while Democrat Hillary Clinton carried the state in 2016. Virginia had previously voted for Republican presidential candidates in 13 out of 14 presidential elections from 1952 to 2004, including 10 in a row from 1968 to 2004.[7] Virginia currently holds its presidential primary election on Super Tuesday, the same day as thirteen other states, with the most recent held on March 3, 2020.[359]
+
+Virginia is the most populous U.S. state without a major professional sports league franchise.[360] The reasons for this include the lack of any dominant city or market within the state, the proximity of teams in Washington, D.C. and North Carolina, and a reluctance to publicly finance stadiums.[361][362] A proposed arena in Virginia Beach designed for an NBA franchise became the latest unsuccessful sports initiative when the city council there ended support in 2017.[363] Norfolk is however host to two minor league teams: The AAA Norfolk Tides and the ECHL's Norfolk Admirals. The San Francisco Giants' AA team, the Richmond Flying Squirrels, began play at The Diamond in 2010, replacing the AAA Richmond Braves, who relocated after 2008.[364] Additionally, the Washington Nationals, Boston Red Sox, Cleveland Indians, Atlanta Braves, Pittsburgh Pirates, New York Yankees, and Toronto Blue Jays also have Single-A and Rookie-level farm teams in Virginia.[365] The Richmond Kickers, a United Soccer League club, have operated since 1993 and are the only team in their league to win both the league championship and the U.S. Open Cup in the same year.[366]
+
+The Washington Football Team have their headquarters in Ashburn and their training facility is in Richmond,[367] and the Washington Capitals train at MedStar Capitals Iceplex in Ballston. Virginia has many professional caliber golf courses including the Greg Norman course at Lansdowne Resort and Kingsmill Resort, home of the Kingsmill Championship, an LPGA Tour tournament. NASCAR currently schedules Monster Energy NASCAR Cup races on two tracks in Virginia: Martinsville Speedway and Richmond Raceway. Virginia natives currently competing in the series include Denny Hamlin and Elliott Sadler.[368]
+
+Virginia does not allow state appropriated funds to be used for either operational or capital expenses for intercollegiate athletics.[370] Despite this, both the Virginia Cavaliers and Virginia Tech Hokies have been able to field competitive teams in the Atlantic Coast Conference and maintain modern facilities. Their rivalry is followed statewide. Twelve other universities compete in NCAA Division I, particularly in the Atlantic 10 Conference, Big South Conference, and Colonial Athletic Association. Three historically Black schools compete in the Division II Central Intercollegiate Athletic Association, and two others (Hampton and Norfolk State) compete in Division I. Several smaller schools compete in the Old Dominion Athletic Conference and the USA South Athletic Conference of NCAA Division III. The NCAA currently holds its Division III championships in football, men's basketball, volleyball and softball in Salem.[371]
+
+The state nickname is its oldest symbol, though it has never been made official by law. Virginia was given the title "Dominion" by King Charles II of England at the time of The Restoration, because it had remained loyal to the crown during the English Civil War, and the present moniker, "Old Dominion" is a reference to that title. Charles' supporters were called Cavaliers, and "The Cavalier State" nickname was popularized after the American Civil War to romanticize the antebellum period. Sports teams from the University of Virginia are called the Cavaliers.[372] The other nickname, "Mother of Presidents", is also historic, as eight Virginians have served as President of the United States, including four of the first five.[1]
+
+The state's motto, Sic Semper Tyrannis, translates from Latin as "Thus Always to Tyrants", and is used on the state seal, which is then used on the flag. While the seal was designed in 1776, and the flag was first used in the 1830s, both were made official in 1930.[373] The majority of the other symbols were made official in the late 20th century.[374] The Virginia reel is among the square dances classified as the state dance.[375] In 1940, Virginia made "Carry Me Back to Old Virginny" the state song, but it was retired in 1997 due to its references to slavery. In March 2015, Virginia named "Our Great Virginia", which uses the tune of "Oh Shenandoah", as the traditional state song and "Sweet Virginia Breeze" as the popular state song.[376]

en/6006.html.txt

@@ -0,0 +1,297 @@
+
+
+West Virginia (/vərˈdʒɪniə/ (listen)) is a state located in the Appalachian region of the Southern United States, though it is also considered to be a part of the Mid-Atlantic Southeast Region.[Note 1] It is bordered by Pennsylvania to the northeast, Maryland to the east and northeast, Virginia to the southeast, Kentucky to the southwest, and Ohio to the northwest. West Virginia is the 41st largest state by area and ranks 38th in population, with around 1.791 million residents. The capital and largest city is Charleston.
+
+West Virginia became a state following the Wheeling Conventions of 1861, at the start of the American Civil War. Delegates from the Unionist counties of northwestern Virginia decided to break away from Virginia, which also included secessionist counties in the new state.[6] West Virginia was admitted to the Union on June 20, 1863, and was a key border state during the war. It was the only state to form by separating from a Confederate state, the first to separate from any state since Maine separated from Massachusetts, and was one of two states (along with Nevada) admitted to the Union during the American Civil War. While a portion of its residents held slaves, most of the residents were yeoman farmers, and the delegates provided for gradual abolition of slavery in the new state Constitution and the state's legislature completely abolished slavery before the end of the war.
+
+The northern panhandle extends adjacent to Pennsylvania and Ohio, with the West Virginia cities of Wheeling and Weirton just across the border from the Pittsburgh metropolitan area, while Bluefield is less than 70 miles (110 km) from North Carolina. Huntington in the southwest is close to the states of Ohio and Kentucky, while Martinsburg and Harpers Ferry in the Eastern Panhandle region are considered part of the Washington metropolitan area, in between the states of Maryland and Virginia. The unique position of West Virginia means it is often included in several U.S. geographical regions, including the Mid-Atlantic, the Upland South, and the Southeastern United States. It is the only state that is entirely within the area served by the Appalachian Regional Commission; the area is commonly defined as "Appalachia".[7]
+
+The state is noted for its mountains and rolling hills, its historically significant logging and coal mining industries, and its political and labor history. It is also known for a wide range of outdoor recreational opportunities, including skiing, whitewater rafting, fishing, hiking, backpacking, mountain biking, rock climbing, and hunting.
+
+Many ancient man-made earthen mounds from various prehistoric mound builder cultures survive, especially in the areas of present-day Moundsville, South Charleston, and Romney. The artifacts uncovered in these give evidence of village societies. They had a tribal trade system culture that crafted cold-worked copper pieces.
+
+In the 1670s during the Beaver Wars, the powerful Iroquois, five allied nations based in present-day New York and Pennsylvania, drove out other American Indian tribes from the region in order to reserve the upper Ohio Valley as a hunting ground. Siouan language tribes, such as the Moneton, had previously been recorded in the area.
+
+A century later, the area now identified as West Virginia was contested territory among Anglo-Americans as well, with the colonies of Pennsylvania and Virginia claiming territorial rights under their colonial charters to this area before the American Revolutionary War. Some speculative land companies, such as the Vandalia Company,[8] and later the Ohio Company and Indiana Company, tried to legitimize their claims to land in parts of West Virginia and present day Kentucky, but failed. This rivalry resulted in some settlers petitioning the Continental Congress to create a new territory called Westsylvania. With the federal settlement of the Pennsylvania and Virginia border dispute, creating Kentucky County, Virginia, Kentuckians "were satisfied [...] and the inhabitants of a large part of West Virginia were grateful."[9]
+
+The Crown considered the area of West Virginia to be part of the British Virginia Colony from 1607 to 1776. The United States considered this area to be the western part of the state of Virginia (which was commonly referred as Trans-Allegheny Virginia) from 1776 to 1863, before the formation of West Virginia. Its residents were discontented for years with their position in Virginia, as the government was dominated by the planter elite of the Tidewater and Piedmont areas. The legislature had electoral malapportionment, based on the counting of slaves toward regional populations, and the western white residents were underrepresented in the state legislature. More subsistence and yeoman farmers lived in the west and they were generally less supportive of slavery, although many counties were divided on their support. The residents of this area became more sharply divided after the planter elite of eastern Virginia voted to secede from the Union during the Civil War.
+
+Residents of the western and northern counties set up a separate government under Francis Pierpont in 1861, which they called the Restored Government. Most voted to separate from Virginia, and the new state was admitted to the Union in 1863. In 1864 a state constitutional convention drafted a constitution, which was ratified by the legislature without putting it to popular vote. West Virginia abolished slavery by a gradual process and temporarily disenfranchised men who had held Confederate office or fought for the Confederacy.
+
+West Virginia's history has been profoundly affected by its mountainous terrain, numerous and vast river valleys, and rich natural resources. These were all factors driving its economy and the lifestyles of its residents, who tended to live in many small, relatively isolated communities in the mountain valleys.
+
+A 2010 analysis of a local stalagmite revealed that Native Americans were burning forests to clear land as early as 100 BCE.[10] Some regional late-prehistoric Eastern Woodland tribes were more involved in hunting and fishing, practicing the Eastern Agricultural Complex gardening method which used fire to clear out underbrush from certain areas. Another group progressed to the more time-consuming, advanced companion crop fields method of gardening. Also continuing from ancient indigenous people of the state, they cultivated tobacco through to early historic times. It was used in numerous social and religious rituals.
+
+"Maize (corn) did not make a substantial contribution to the diet until after 1150 BP", to quote Mills (OSU 2003).[full citation needed] Eventually, tribal villages began depending on corn to feed their turkey flocks, as Kanawha Fort Ancients practiced bird husbandry. The local Indians made corn bread and a flat rye bread called "bannock" as they emerged from the protohistoric era. A horizon extending from a little before the early 18th century is sometimes called the acculturating Fireside Cabin culture. Trading posts were established by European traders along the Potomac and James rivers.
+
+Tribes that inhabited West Virginia as of 1600 were the Siouan Monongahela Culture to the north, the Fort Ancient culture along the Ohio River from the Monongahela to Kentucky and extending an unknown distance inland,[11] and the Eastern Siouan Tutelo and Moneton tribes in the southeast. There was also the Iroquoian Susquehannock in the region approximately east of the Monongahela River and north of the Monongahela National Forest, a possible tribe called the Senandoa, or Shenandoah, in the Shenandoah Valley and the easternmost tip of the state may have been home to the Manahoac people. The Monongahela may have been the same as a people known as the Calicua, or Cali.[12] The following may have also all been the same tribe—Moneton, Moheton, Senandoa, Tomahitan.
+
+During the Beaver Wars, other tribes moved into the region. There was the Iroquoian Tiontatecaga (also Little Mingo, Guyandotte),[13] who seem to have split off from the Petun after they were defeated by the Iroquois. They eventually settled somewhere between the Kanawha and Little Kanawha Rivers. During the 1750s, when the Mingo Seneca seceded from the Iroquois and returned to the Ohio River Valley, they contend that this tribe merged with them. The Shawnee arrived as well, but were primarily stationed within former Monongahela territory approximately until 1750, however they did extend their influence throughout the Ohio River region. They were the last Native tribe of West Virginia and were driven out by the United States during the Shawnee Wars (1811–1813). The Erie, who were chased out of Ohio around 1655, are now believed to be the same as the Westo, who invaded as far as South Carolina before being destroyed in the 1680s. If so, their path would have brought them through West Virginia. The historical movement of the Tutelo,[14] as well as Carbon dating for the Fort Ancients seem to correspond with the given period of 1655–1670 as the time of their removal.[11] The Susquehannocks were original participants of the Beaver Wars, but were cut off from the Ohio River by the Iroquois around 1630 and found themselves in dire straits. From disease, constant warfare and an inability to provide for themselves financially, they began to collapse and moved further and further east, to the Susquehanna River of Eastern Pennsylvania.[15] The Manahoac were probably forced out in the 1680s, when the Iroquois began to invade Virginia.[16] The Siouan tribes there moved into North Carolina and later returned as one tribe, known as the Eastern Blackfoot, or Christannas.[17]
+
+The Westo did not secure the territory they conquered. Before they were even gone, displaced natives from the south flooded into freshly conquered regions and took them over.[18] These became known as the Shattaras, or West Virginia Cherokees. They took in and merged with the Monetons, who began to refer to themselves as the Mohetons. The Calicua also began to refer to themselves as Cherokees soon after, showing an apparent further merger. These Shattaras were closely related to the tribes which formed to the south in the aftermath of the Westo—the Yuchi and Cherokee. From 1715–1717, the Yamasee War sprang up. The Senandoa allegedly sided with the Yuchi and were destroyed by Yamasee allies.[19] Therefore, if the Senandoa were the same tribe as the Moneton, this would mean the collapse of Shattara-Moneton culture. Another tribe who appeared in the region were the Canaragay, or Kanawha.[20] They later migrated to Maryland and merged into colonial culture.
+
+In 1671, General Abraham Wood, at the direction of Royal Governor William Berkeley of the Virginia Colony, sent a party from Fort Henry led by Thomas Batts and Robert Fallam to survey this territory. They were the first Europeans recorded as discovering Kanawha Falls. Some sources state that Governor Alexander Spotswood's 1716 Knights of the Golden Horseshoe Expedition (for which the state's Golden Horseshoe Competition for 8th graders was named) had penetrated as far as Pendleton County; however, modern historians interpret the original accounts of the excursion as suggesting that none of the expedition's horsemen ventured much farther west of the Blue Ridge Mountains than Harrisonburg, Virginia. John Van Metre, an Indian trader, penetrated into the northern portion in 1725. The same year, German settlers from Pennsylvania founded New Mecklenburg, the present Shepherdstown, on the Potomac River, and others followed.[21]
+
+King Charles II of England, in 1661, granted to a company of gentlemen the land between the Potomac and Rappahannock rivers, known as the Northern Neck. Thomas Fairfax, 6th Lord Fairfax of Cameron ultimately took possession of this grant, and in 1746, a stone was erected at the source of the North Branch Potomac River to mark the western limit of his grant. A considerable part of this land was surveyed by the young George Washington between 1748 and 1751. The diary kept by Washington recorded that there were already many squatters, largely of German origin, along the South Branch Potomac River.[22]
+
+Christopher Gist, a surveyor in the employ of the first Ohio Company, which was composed chiefly of Virginians, explored the country along the Ohio River north of the mouth of the Kanawha River between 1751 and 1752. The company sought to have a fourteenth colony established with the name "Vandalia". Many settlers crossed the mountains after 1750, though they were hindered by Native American resistance. Few Native Americans lived permanently within the present limits of the state, but the region was a common hunting ground, crossed by many trails. During the French and Indian War (the North American front of the Seven Years' War in Europe), Indian allies of the French nearly destroyed the scattered British settlements.[23]
+
+Shortly before the American Revolutionary War, in 1774 the Crown Governor of Virginia John Murray, 4th Earl of Dunmore, led a force over the mountains. A body of militia under then-Colonel Andrew Lewis dealt the Shawnee Indians, under Hokoleskwa (or "Cornstalk"), a crushing blow during the Battle of Point Pleasant at the junction of the Kanawha and the Ohio rivers.[23] At the Treaty of Camp Charlotte concluding Dunmore's War, Cornstalk agreed to recognize the Ohio River as the new boundary with the "Long Knives". By 1776, however, the Shawnee had returned to war, joining the Chickamauga, a band of Cherokee known for the area where they lived.[citation needed] Native American attacks on settlers continued until after the American Revolutionary War. During the war, the settlers in western Virginia were generally active Whigs and many served in the Continental Army.[23] However, Claypool's Rebellion of 1780–1781, in which a group of men refused to pay taxes imposed by the Continental Army, showed war-weariness in what became West Virginia.
+
+Social conditions in western Virginia were entirely unlike those in the eastern portion of the state. The population was not homogeneous, as a considerable part of the immigration came by way of Pennsylvania and included Germans, Protestant Scotch-Irish, and settlers from the states farther north. Counties in the east and south were settled mostly by eastern Virginians. During the American Revolution, the movement to create a state beyond the Alleghenies was revived and a petition for the establishment of "Westsylvania" was presented to Congress, on the grounds that the mountains presented an almost impassable barrier to the east. The rugged nature of the country made slavery unprofitable, and time only increased the social, political, economic, and cultural differences (see Tuckahoe-Cohee) between the two sections of Virginia.[23]
+
+In 1829, a constitutional convention met in Richmond to consider reforms to Virginia's outdated constitution. Philip Doddridge of Brooke County championed the cause of western Virginians who sought a more democratic frame of government.[24] However, western reforms were rejected by leaders from east of the Alleghenies who "clung to political power in an effort to preserve their plantation lifestyles dependent on enslaving blacks".[25] Virginia leaders maintained a property qualification for suffrage effectively disenfranchising poorer farmers in the west whose families did much of the farm-work themselves. In addition, the 1829–1830 convention gave the slave-holding counties the benefit of three-fifths of their slave population in apportioning the state's representation in the U.S. House of Representatives. As a result, every county west of the Alleghenies except one voted to reject the constitution, which nevertheless passed because of eastern support.[23] Failure of the eastern planter elite to make constitutional reforms exacerbated existing east–west sectionalism in Virginia and contributed to Virginia's later division.[26]
+
+The Virginia Constitutional Convention of 1850–51, the Reform Convention, addressed a number of issues important to western Virginians. It extended the vote to all white males 21 years or older. The governor, lieutenant governor, the judiciary, sheriffs, and other county officers were to be elected by public vote. The composition of the General Assembly was changed. Representation in the house of delegates was apportioned on the basis of the census of 1850, counting whites only. The Senate representation was arbitrarily fixed at 50 seats, with the west receiving twenty, and the east thirty senators. This was made acceptable to the west by a provision that required the General Assembly to reapportion representation on the basis of white population in 1865, or else put the matter to a public referendum. But the east also gave itself a tax advantage in requiring a property tax at true and actual value, except for slaves. Slaves under the age of 12 years were not taxed and slaves over that age were taxed at only $300, a fraction of their true value. Small farmers, however, had all their assets, animals, and land taxed at full value. Despite this tax and the lack of internal improvements in the west, the vote was 75,748 for and 11,063 against the new Constitution. Most of the opposition came from delegates from eastern counties, who did not like the compromises made for the west.[27]
+
+Given these differences, many in the west had long contemplated a separate state. In particular, men such as lawyer Francis H. Pierpont from Fairmont, had long chafed under the political domination of the Tidewater and Piedmont slave-holders. In addition to differences over the abolition of slavery, he and allies felt the Virginia government ignored and refused to spend funds on needed internal improvements in the west, such as turnpikes and railroads.[28]
+
+West Virginia was the only state in the Union to separate from a Confederate state (Virginia) during the American Civil War.[30] In Richmond on April 17, 1861, the Virginia Secession Convention of 1861 voted to secede from the Union, but of the 49 delegates from the northwestern corner (which ultimately became West Virginia) only 17 voted in favor of the Ordinance of Secession, while 30 voted against[31] (with two abstentions).[32] Almost immediately after that vote, a mass meeting at Clarksburg recommended that each county in northwestern Virginia send delegates to a convention to meet in Wheeling on May 13, 1861. When this First Wheeling Convention met, 425 delegates from 25 counties were present, though more than one-third of the delegates were from the northern panhandle area.[33] Soon, there was a division of sentiment.[23]
+
+Some delegates led by John S. Carlile favored the immediate formation of a new state, while others led by Waitman Willey argued that, as Virginia's secession had not yet been passed by the required referendum (as happened on May 23), such action would constitute revolution against the United States.[34] The convention decided that if Virginians adopted the secession ordinance (of which there was little doubt), another convention including the members-elect of the legislature would meet in Wheeling in June 1861. On May 23, 1861, secession was ratified by a large majority in Virginia as a whole, but in the western counties 34,677 voted against and 19,121 voted for the Ordinance.[35]
+
+The Second Wheeling Convention met as agreed on June 11 and declared that, since the Secession Convention had been called without popular consent, all its acts were void and that all who adhered to it had vacated their offices.[23] The Wheeling Conventions, and the delegates themselves, were never actually elected by public ballot to act on behalf of western Virginia.[36] Of its 103 members, 33 had been elected to the Virginia General Assembly[37] on May 23. This included some hold-over state senators whose four-year terms had begun in 1859, and some who vacated their offices to convene in Wheeling. Other members "were chosen even more irregularly—some in mass meetings, others by county committee, and still others were seemingly self-appointed".[38] An act for the reorganization of the government was passed on June 19. The next day convention delegates chose Francis H. Pierpont as governor of Virginia, and elected other officers to a rival state government and two U.S. senators (Willey and Carlile) to replace secessionists before adjourning. The federal government in Washington, D.C. promptly recognized the new government and seated the two new senators. Thus, there were two state governments in Virginia: one pledging allegiance to the United States and one to the Confederacy.[23]
+
+The second Wheeling Convention had recessed until August 6, then reassembled on August 20 and called for a popular vote on the formation of a new state and for a convention to frame a constitution if the vote should be favorable. At the October 24, 1861 election, 18,408 votes were cast for the new state and only 781 against.[23] The election results were questioned, since the Union army then occupied the area and Union troops were stationed at many of the polls to prevent Confederate sympathizers from voting.[39] This was also election day for local offices, and elections were also held in camps of Confederate soldiers, who elected rival state officials, such as Robert E. Cowan. Most pro-statehood votes came from 16 counties around the Northern panhandle.[40] Over 50,000 votes had been cast on the Ordinance of Secession, yet the vote on statehood garnered little more than 19,000.[41] In Ohio County, home to Wheeling, only about a fourth of the registered voters cast votes.[42] In most of what would become West Virginia, there was no vote at all, as two-thirds of the territory of West Virginia had voted for secession and county officers remained loyal to Richmond. Votes recorded from pro-secession counties were mostly cast elsewhere by Unionist refugees from these counties.[43]
+
+Despite that controversy, delegates (including many Methodist ministers) met to write a new Constitution for the new state, beginning on November 26, 1861. During that constitutional convention, a Mr. Lamb of Ohio County and a Mr. Carskadon claimed that in Hampshire County, out of 195 votes only 39 were cast by citizens of the state; the rest were cast illegally by Union soldiers.[44] One of the key figures was Rev. Gordon Battelle, who also represented Ohio County, and who proposed resolutions to establish public schools, as well as to limit movement of slaves into the new state, and to gradually abolish slavery. The education proposal succeeded, but the convention tabled the slavery proposals before finishing its work on February 18, 1862. The new constitution was more closely modeled on that of Ohio than of Virginia, adopting a township model of government rather than the "courthouse cliques" of Virginia which Carlile criticized, and a compromise demanded by the Kanawha region (Charleston lawyers Benjamin Smith and Brown) allowed counties and municipalities to vote subsidies for railroads or other improvement organizations.[45] The resulting instrument was ratified (18,162 for and 514 against) on April 11, 1862.
+
+On May 13, 1862 the state legislature of the reorganized government approved the formation of the new state. An application for admission to the Union was made to Congress, introduced by Senator Waitman Willey of the Restored Government of Virginia. However, Sen. Carlile sought to sabotage the bill, first trying to expand the new state's boundaries to include the Shenandoah Valley, and then to defeat the Willey amendment at home.[46] On December 31, 1862, an enabling act was approved by President Abraham Lincoln admitting West Virginia, on the condition that a provision for the gradual abolition of slavery be inserted in its constitution[23] (as Rev. Battelle had urged in the Wheeling Intelligencer and also written to Lincoln). While many felt West Virginia's admission as a state was both illegal and unconstitutional, Lincoln issued his Opinion on the Admission of West Virginia finding that "the body which consents to the admission of West Virginia is the Legislature of Virginia", and that its admission was therefore both constitutional and expedient.[47]
+
+The convention was reconvened on February 12, 1863, and the abolition demand of the federal enabling act was met. The revised constitution was adopted on March 26, 1863 and on April 20, 1863, President Lincoln issued a proclamation admitting the state 60 days later on June 20, 1863. Meanwhile, officers for the new state were chosen, while Gov. Pierpont moved his pro-Union Virginia capital to Union-occupied Alexandria, where he asserted and exercised jurisdiction over all the remaining Virginia counties within the federal lines.[23]
+
+The question of the constitutionality of the formation of the new state was later brought before the Supreme Court of the United States in Virginia v. West Virginia. Berkeley and Jefferson counties lying on the Potomac east of the mountains, in 1863, with the consent of the reorganized government of Virginia voted in favor of annexation to West Virginia.[23]
+
+Many voters of the strongly pro-secessionist counties were absent in the Confederate Army when the vote was taken and refused to acknowledge the transfer when they returned. The Virginia General Assembly repealed the act of secession and, in 1866, brought suit against West Virginia asking the court to declare the counties a part of Virginia, which would have declared West Virginia's admission as a state unconstitutional. Meanwhile, on March 10, 1866, Congress passed a joint resolution recognizing the transfer.[23] The Supreme Court decided in favor of West Virginia in 1870.[48]
+
+During the Civil War, Union General George B. McClellan's forces gained possession of the greater part of the territory in the summer of 1861, culminating at the Battle of Rich Mountain, and Union control was never again seriously threatened. In 1863, General John D. Imboden, with 5,000 Confederates, raided a considerable portion of the state and burned Pierpont's library, although Senator Willey escaped their grasp. Bands of guerrillas burned and plundered in some sections, and were not entirely suppressed until after the war ended.[23] The Eastern Panhandle counties were more affected by the war, with military control of the area repeatedly changing hands.
+
+The area that became West Virginia actually furnished about an equal number of soldiers to the federal and Confederate armies,[49] approximately 22,000–25,000 each. In 1865, the Wheeling government found it necessary to strip voting rights from returning Confederates in order to retain control. James Ferguson, who proposed the law, said if it was not enacted he would lose election by 500 votes.[50] The property of Confederates might also be confiscated, and in 1866 a constitutional amendment disfranchising all who had given aid and comfort to the Confederacy was adopted. The addition of the Fourteenth and Fifteenth Amendments to the United States Constitution caused a reaction. The Democratic party secured control in 1870, and in 1871, the constitutional amendment of 1866 was abrogated. The first steps toward this change had been taken, however, by the Republicans in 1870. On August 22, 1872, an entirely new constitution was adopted.[23]
+
+Beginning in Reconstruction, and for several decades thereafter, the two states disputed the new state's share of the pre-war Virginia government's debts, which had mostly been incurred to finance public infrastructure improvements, such as canals, roads, and railroads under the Virginia Board of Public Works. Virginians—led by former Confederate general William Mahone—formed a political coalition based upon this: the Readjuster Party. Although West Virginia's first constitution provided for the assumption of a part of the Virginia debt, negotiations opened by Virginia in 1870 were fruitless, and in 1871, Virginia funded two-thirds of the debt and arbitrarily assigned the remainder to West Virginia.[51] The issue was finally settled in 1915, when the Supreme Court of the United States ruled that West Virginia owed Virginia $12,393,929.50.[52] The final instalment of this sum was paid in 1939.
+
+After Reconstruction, the new 35th state benefited from the development of its mineral resources more than any other single economic activity.
+
+Saltpeter caves had been employed throughout Appalachia for munitions; the border between West Virginia and Virginia includes the "Saltpeter Trail", a string of limestone caverns containing rich deposits of calcium nitrate which were rendered and sold to the government. The trail stretched from Pendleton County to the western terminus of the route in the town of Union, Monroe County. Nearly half of these caves are on the West Virginia side, including Organ Cave and Haynes Cave. In the late 18th-century, saltpeter miners in Haynes Cave found large animal bones in the deposits. These were sent by a local historian and frontier soldier Colonel John Stuart to Thomas Jefferson. The bones were named Megalonyx jeffersonii, or great-claw, and became known as Jefferson's three-toed sloth. It was declared the official state fossil of West Virginia in 2008. The West Virginia official state rock is bituminous coal,[53] and the official state gemstone is silicified Mississippian fossil Lithostrotionella coral.[54]
+
+The limestone also produced a useful quarry industry, usually small, and softer, high-calcium seams were burned to produce industrial lime. This lime was used for agricultural and construction purposes; for many years a specific portion of the C & O Railroad carried limestone rock to Clifton Forge, Virginia as an industrial flux.
+
+Salt mining had been underway since the 18th century, though it had largely played out by the time of the American Civil War, when the red salt of Kanawha County was a valued commodity of first Confederate, and later Union, forces. In years following, more sophisticated mining methods would restore West Virginia's role as a major producer of salt.
+
+However, in the second half of the 19th century, there was an even greater treasure not yet developed: bituminous coal. It would fuel much of the Industrial Revolution in the U.S. and the steamships of many of the world's navies.
+
+The residents (both Native Americans and early European settlers) had long known of the underlying coal, and that it could be used for heating and fuel.  However, for a long time, "personal" or artisanal mining was the only practical development.  After the War, with the new railroads came a practical method to transport large quantities of coal to expanding U.S. and export markets. As the anthracite mines of northwestern New Jersey and Pennsylvania began to play out during this same time period, investors and industrialists focused new interest in West Virginia. Geologists such as Dr. David T. Ansted surveyed potential coal fields and invested in land and early mining projects.
+
+The completion of the Chesapeake and Ohio Railway (C&O) across the state to the new city of Huntington on the Ohio River in 1872 opened access to the New River Coal Field. Soon, the C&O was building its huge coal pier at Newport News, Virginia on the large harbor of Hampton Roads. In 1881, the new Philadelphia-based owners of the former Atlantic, Mississippi and Ohio Railroad (AM&O), which stretched across Virginia's southern tier from Norfolk, had sights clearly set on the Mountain State, where the owners had large land holdings. Their railroad was renamed Norfolk and Western (N&W), and a new railroad city was developed at Roanoke to handle planned expansion. After its new president Frederick J. Kimball and a small party journeyed by horseback and saw firsthand the rich bituminous coal seam, which Kimball's wife named Pocahontas, the N&W redirected its planned westward expansion to reach it. Soon, the N&W was also shipping from new coal piers at Hampton Roads.
+
+In 1889, in the southern part of the state, along the Norfolk and Western rail lines, the important coal center of Bluefield, West Virginia was founded. The "capital" of the Pocahontas coalfield, this city would remain the largest city in the southern portion of the state for several decades. It shares a sister city with the same name, Bluefield, in Virginia.
+
+In the northern portion of the state and elsewhere, the older Baltimore and Ohio Railroad (B&O) and other lines also expanded to take advantage of coal opportunities. The B&O developed coal piers in Baltimore and at several points on the Great Lakes. Other significant rail carriers of coal were the Western Maryland Railway (WM), Southern Railway (SOU), and the Louisville and Nashville Railroad (L&N).
+
+Particularly notable was a latecomer, the Virginian Railway (VGN). By 1900 only the most rugged terrain of southern West Virginia was any distance from the existing railroads and mining activity. Within this area west of the New River Coalfield in Raleigh and Wyoming counties lay the Winding Gulf Coalfield, later promoted as the "Billion Dollar Coalfield".
+
+A protégé of Dr. Ansted was William Nelson Page (1854–1932), a civil engineer and mining manager in Fayette County. Former West Virginia governor William A. MacCorkle described him as a man who knew the land "as a farmer knows a field". Beginning in 1898, Page teamed with northern and European-based investors to take advantage of the undeveloped area. They acquired large tracts of land in the area, and Page began the Deepwater Railway, a short-line railroad chartered to stretch between the C&O at its line along the Kanawha River and the N&W at Matoaka—a distance of about 80 miles (130 km).
+
+Although the Deepwater plan should have provided a competitive shipping market via either railroad, leaders of the two large railroads did not appreciate the scheme. In secret collusion, each declined to negotiate favorable rates with Page, nor did they offer to purchase his railroad, as they had many other short-lines. However, if the C&O and N&W presidents thought they could thus kill the Page project, they were to be proved mistaken. One of the silent partner investors Page had enlisted was millionaire industrialist Henry Huttleston Rogers, a principal in John D. Rockefeller's Standard Oil Trust and an old hand at developing natural resources and transportation. A master at competitive "warfare", Henry Rogers did not like to lose in his endeavors and also had "deep pockets".
+
+Instead of giving up, Page (and Rogers) quietly planned and then built their tracks all the way east across Virginia, using Rogers' private fortune to finance the $40 million cost. When the renamed Virginian Railway (VGN) was completed in 1909, no fewer than three railroads were shipping ever-increasing volumes of coal to export from Hampton Roads. West Virginia coal was also under high demand at Great Lakes ports. The VGN and the N&W ultimately became parts of the modern Norfolk Southern system, and the VGN's well-engineered 21st-century tracks continue to offer a favorable gradient to Hampton Roads.
+
+As coal mining and related work became major employment activities in the state, there was considerable labor strife as working conditions, safety issues and economic concerns arose. Even in the 21st century, mining safety and ecological concerns is still challenging to the state whose coal continues to power electrical generating plants in many other states.
+
+Coal is not the only valuable mineral found in West Virginia, as the state was the site of the 1928 discovery of the 34.48 carat (6.896 g) Jones Diamond.
+
+Located in the Appalachian Mountain range, West Virginia covers an area of 24,229.76 square miles (62,754.8 km2), with 24,077.73 square miles (62,361.0 km2) of land and 152.03 square miles (393.8 km2) of water, making it the 41st-largest state in the United States.[55] West Virginia borders Pennsylvania and Maryland in the northeast, Virginia in the southeast, Ohio in the northwest, and Kentucky in the southwest. Its longest border is with Virginia at 381 miles (613 km), followed by Ohio at 243 miles (391 km), Maryland at 174 miles (280 km), Pennsylvania at 118 miles (190 km), and Kentucky at 79 miles (127 km).[56]
+
+West Virginia is located entirely within the Appalachian Region, and the state is almost entirely mountainous, giving reason to the nickname The Mountain State and the motto Montani Semper Liberi ("Mountaineers are always free"). The elevations and ruggedness drop near large rivers like the Ohio River or Shenandoah River. About 75% of the state is within the Cumberland Plateau and Allegheny Plateau regions. Though the relief is not high, the plateau region is extremely rugged in most areas. The average elevation of West Virginia is approximately 1,500 feet (460 m) above sea level, which is the highest of any U.S. state east of the Mississippi River.
+
+On the eastern state line with Virginia, high peaks in the Monongahela National Forest region give rise to an island of colder climate and ecosystems similar to those of northern New England and eastern Canada. The highest point in the state is atop Spruce Knob, at 4,863 feet (1,482 m),[57] and is covered in a boreal forest of dense spruce trees at altitudes above 4,000 feet (1,200 m). Spruce Knob lies within the Monongahela National Forest and is a part of the Spruce Knob-Seneca Rocks National Recreation Area.[58] A total of six wilderness areas can also be found within the forest. Outside the forest to the south, the New River Gorge is a canyon 1,000 feet (300 m) deep, carved by the New River. The National Park Service manages a portion of the gorge and river that has been designated as the New River Gorge National River, one of only fifteen rivers in the U.S. with this level of protection.
+
+Other areas under protection and management include:
+
+Most of West Virginia lies within the Appalachian mixed mesophytic forests ecoregion, while the higher elevations along the eastern border and in the panhandle lie within the Appalachian-Blue Ridge forests. The native vegetation for most of the state was originally mixed hardwood forest of oak, chestnut, maple, beech, and white pine, with willow and American sycamore along the state's waterways. Many of the areas are rich in biodiversity and scenic beauty, a fact appreciated by native West Virginians, who refer to their home as Almost Heaven (from the song, "Take Me Home, Country Roads" by John Denver). Before the song, it was known as "The Cog State" (Coal, Oil, and Gas) or "The Mountain State".
+
+The underlying rock strata are sandstone, shale, bituminous coal beds, and limestone laid down in a near-shore environment from sediments derived from mountains to the east, in a shallow inland sea on the west. Some beds illustrate a coastal swamp environment, some river delta, some shallow water. Sea level rose and fell many times during the Mississippian and Pennsylvanian eras, giving a variety of rock strata. The Appalachian Mountains are some of the oldest on earth, having formed more than three hundred million years ago.[59]
+
+The climate of West Virginia is generally a humid subtropical climate (Köppen climate classification Cfa, except Dfb at the higher elevations) with warm to hot, humid summers and chilly winters, increasing in severity with elevation. Some southern highland areas also have a mountain temperate climate (Köppen Cfb) where winter temperatures are more moderate and summer temperatures are somewhat cooler. However, the weather is subject in all parts of the state to change. The hardiness zones range from zone 5b in the central Appalachian mountains to zone 7a in the warmest parts of the lowest elevations.[60]
+
+In the Eastern Panhandle and the Ohio River Valley, temperatures are warm enough to see and grow subtropical plants such as southern magnolia (Magnolia grandiflora), crepe myrtle, Albizia julibrissin, American sweetgum and even the occasional needle palm and sabal minor. These plants do not thrive as well in other parts of the state. The eastern prickly pear grows well in many portions of the state.
+
+Average January temperatures range from around 26 °F (−4 °C) near the Cheat River to 41 °F (5 °C) along sections of the border with Kentucky. July averages range from 67 °F (19 °C) along the North Branch Potomac River to 76 °F (24 °C) in the western part of the state. It is cooler in the mountains than in the lower sections of the state.[61] The highest recorded temperature in the state is 112 °F (44 °C) at Martinsburg on July 10, 1936 and the lowest recorded temperature in the state is −37 °F (−38 °C) at Lewisburg on December 30, 1917.
+
+Annual precipitation ranges from less than 32 inches (810 mm) in the lower eastern section to more than 56 inches (1,400 mm) in higher parts of the Allegheny Front. Valleys in the east have lower rainfall because the Allegheny mountain ridges to the west create a partial rain shadow. Slightly more than half the rainfall occurs from April to September. Dense fogs are common in many valleys of the Kanawha section, especially the Tygart Valley. West Virginia is also one of the cloudiest states in the nation, with the cities of Elkins and Beckley ranking 9th and 10th in the U.S. respectively for the number of cloudy days per year (over 210). In addition to persistent cloudy skies caused by the damming of moisture by the Alleghenies, West Virginia also experiences some of the most frequent precipitation in the nation, with Snowshoe averaging nearly 200 days a year with either rain or snow. Snow usually lasts only a few days in the lower sections but may persist for weeks in the higher mountain areas. An average of 34 inches (860 mm) of snow falls annually in Charleston, although during the winter of 1995–1996 more than three times that amount fell as several cities in the state established new records for snowfall. Average snowfall in the Allegheny Highlands can range up to 180 inches (4,600 mm) per year. Severe weather is somewhat less prevalent in West Virginia than in most other eastern states, and it ranks among the least tornado-prone states east of the Rockies.
+
+The United States Census Bureau estimates that the population of West Virginia was 1,792,147 on July 1, 2018, a 3.28% decrease since the 2010 United States Census.[63] The center of population of West Virginia is located in Braxton County, in the town of Gassaway.[64]
+
+At the 2010 Census, the racial composition of the state's population was:
+
+In the same year, 1.2% of West Virginia's population was of Hispanic, Latino, or Spanish origin (they may be of any race).
+
+As of 2018, West Virginia has an estimated population of 1,805,832, which is a decrease of 10,025 (0.55%) from the prior year and a decrease of 47,162 (2.55%) since the previous census. This includes a natural decrease of 3,296 (108,292 births minus 111,588 deaths) and an increase from net migration of 14,209 into the state. West Virginia is the least populous southeastern state. Immigration from outside the United States resulted in a net increase of 3,691, and migration within the country produced a net increase of 10,518.
+
+Only 1.1% of the state's residents were foreign-born, placing West Virginia last among the 50 states in that statistic. It also has the lowest percentage of residents who speak a language other than English in the home (2.7%).
+
+The five largest ancestry groups in West Virginia are: German (18.9%), Irish (15.1%) American (12.9%), English (11.8%) and Italian (4.7%)[68][69] In the 2000 Census People who identified their ethnicity as simply American made up 18.7% of the population.[70]
+
+Large numbers of people of German ancestry are present in the northeastern counties of the state. People of English ancestry are present throughout the entire state. Many West Virginians who self-identify as Irish are actually Scots-Irish Protestants.
+
+2010 census data show that 16 percent of West Virginia's residents are 65 or older (exceeded only by Florida's 17 percent).[71]
+
+There were 20,928 births in 2006. Of these, 19,757 (94.40% of the births, 95.19% of the population) were to non-Hispanic whites. There were 22 births to American Indians (0.11% of the births and 0.54% of the population), 177 births to Asians (0.85% of the births and 0.68% of the population), 219 births to Hispanics (1.05% of the births and 0.88% of the population) and 753 births to blacks and others (3.60% of the births and 3.56% of the population).[73]
+
+The state's Northern Panhandle, and North-Central region feel an affinity for Pittsburgh, Pennsylvania. Also, those in the Eastern Panhandle feel a connection with the Washington, D.C. suburbs in Maryland and Virginia, and southern West Virginians often consider themselves Southerners. Finally, the towns and farms along the mid-Ohio River, which forms most of the state's western border, have an appearance and culture somewhat resembling the Midwest.[74]
+
+Note: Births in table do not add up, because Hispanics are counted both by their ethnicity and by their race, giving a higher overall number.
+
+Several surveys have been made in recent years, in 2008 by the American Religion Identity Survey,[83] in 2010 by the Pew Forum on Religion and Public Life.[84] The Pew survey results admit to a 6.5% margin of error plus or minus, while the ARIS survey says "estimates are subject to larger sampling errors in states with small populations." A characteristic of religion in Appalachian communities is the abundance of independent, non-affiliated churches, which "remain unnoted and uncounted in any census of church life in the United States". This sometimes leads to the belief that these communities are "unchurched".[85]
+
+The largest denomination as of 2010 was the United Methodist Church with 136,000 members in 1,200 congregations. The second-largest Protestant church was the American Baptist Churches USA with 88,000 members and 381 congregations. The Southern Baptist church had 44,000 members and 232 congregations. The Churches of Christ had 22,000 members and 287 congregations. The Presbyterian Church (USA) had 200 congregations and 20,000 members.[86]
+
+A survey conducted in 2015 by the Pew Research Center found that West Virginia was the seventh most "highly religious" state in the United States.[87]
+
+The economy of West Virginia nominally would be the 62nd largest economy globally behind Iraq and ahead of Croatia according to 2009 World Bank projections,[88] and the 64th largest behind Iraq and ahead of Libya according to 2009 International Monetary Fund projections.[89] The state has a projected nominal GSP of $63.34 billion in 2009 according to the Bureau of Economic Analysis report of November 2010, and a real GSP of $55.04 billion. The real GDP growth of the state in 2009 of .7% was the 7th best in the country.[90] West Virginia was one of only ten states in 2009 that grew economically.[91]
+
+While per capita income fell 2.6% nationally in 2009, West Virginia's grew at 1.8%.[92] Through the first half of 2010, exports from West Virginia topped $3 billion, growing 39.5% over the same period from the previous year and ahead of the national average by 15.7%.[92]
+
+Morgantown was ranked by Forbes as the #10 best small city in the nation to conduct business in 2010.[93] The city is also home to West Virginia University, the 95th best public university according to U.S. News & World Report in 2011.[94] The proportion of West Virginia's adult population with a bachelor's degree is the lowest in the U.S. at 17.3%.[95]
+
+The net corporate income tax rate is 6.5% while business costs are 13% below the national average.[96][97]
+
+The U.S. Bureau of Economic Analysis reported that in 2014 West Virginia's economy grew twice as fast as the next fastest growing state East of the Mississippi River, ranking third alongside Wyoming and just behind North Dakota and Texas among the fastest growing states in the United States.[98]
+
+Tourism contributed $4.27 billion to the state's economy and employed 44,400 people in 2010, making it one of the state's largest industries.[99] Many tourists, especially in the eastern mountains, are drawn to the region's notable opportunities for outdoor recreation. Canaan Valley is popular for winter sports, Seneca Rocks is one of the premier rock climbing destinations in the eastern U.S., the New River Gorge/Fayetteville area draws rock climbers as well as whitewater rafting enthusiasts, and the Monongahela National Forest is popular with hikers, backpackers, hunters, and anglers.
+
+In addition to such outdoor recreation opportunities, the state offers a number of historic and cultural attractions. Harpers Ferry National Historical Park is a historic town situated at the confluence of the Shenandoah and Potomac rivers. Harpers Ferry was the site of John Brown's 1859 raid on the U.S. Armory and Arsenal. Located at the approximate midpoint of the Appalachian Trail, Harpers Ferry is the base of the Appalachian Trail Conservancy.
+
+The Greenbrier hotel and resort, originally built in 1778, has long been considered a premier hotel, frequented by numerous world leaders and U.S. presidents over the years.
+
+West Virginia is the site of the National Radio Astronomy Observatory, which features the Green Bank Telescope. For the 1963 Centennial of the State, it hosted two high school graduate delegates from each of the 50 States at the National Youth Science Camp near Bartow, and has continued this tradition ever since. The main building of Weston State Hospital is the largest hand-cut sandstone building in the western hemisphere, second worldwide only to the Kremlin in Moscow. Tours of the building, which is a National Historic Landmark and part of the National Civil War Trail, are offered seasonally and by appointment year round. West Virginia has numerous popular festivals throughout the year.
+
+One of the major resources in West Virginia's economy is coal. According to the Energy Information Administration, West Virginia is a top coal-producer in the United States, second only to Wyoming. West Virginia is located in the heart of the Marcellus Shale Natural Gas Bed, which stretches from Tennessee north to New York in the middle of Appalachia.
+
+As of 2017, the coal industry accounted for 2% of state employment.[100]
+
+Nearly all the electricity generated in West Virginia is from coal-fired power plants. West Virginia produces a surplus of electricity and leads the Nation in net interstate electricity exports.[101] Farming is also practiced in West Virginia, but on a limited basis because of the mountainous terrain over much of the state.
+
+West Virginia has the potential to generate 4,952 GWh/year from 1,883 MW of wind power, using 80 meter high wind turbines, or 8,627 GWh/year from 2,772 MW of 100 meter wind turbines, and 60,000 GWh from 40,000 MW of photovoltaics, including 3,810 MW of rooftop photovoltaics.[102]
+
+Source:[104][105][106][107]
+
+West Virginia personal income tax is based on federal adjusted gross income (not taxable income), as modified by specific items in West Virginia law. Citizens are taxed within five income brackets, which range from 3.0% to 6.5%. The state's consumer sales tax is levied at 6% on most products except for non-prepared foods.[108]
+
+West Virginia counties administer and collect property taxes, although property tax rates reflect levies for state government, county governments, county boards of education and municipalities. Counties may also impose a hotel occupancy tax on lodging places not located within the city limits of any municipality that levies such a tax. Municipalities may levy license and gross receipts taxes on businesses located within the city limits and a hotel occupancy tax on lodging places in the city. Although the Department of Tax and Revenue plays a major role in the administration of this tax, less than half of one percent of the property tax collected goes to state government.
+
+The primary beneficiaries of the property tax are county boards of education. Property taxes are paid to the sheriff of each of the state's 55 counties. Each county and municipality can impose its own rates of property taxation within the limits set by the West Virginia Constitution. The West Virginia legislature sets the rate of tax of county boards of education. This rate is used by all county boards of education statewide. However, the total tax rate for county boards of education may differ from county to county because of excess levies. The Department of Tax and Revenue supervises and otherwise assists counties and municipalities in their work of assessment and tax rate determination. The total tax rate is a combination of the tax levies from four state taxing authorities: state, county, schools and municipal. This total tax rate varies for each of the four classes of property, which consists of personal, real and intangible properties. Property is assessed according to its use, location and value as of July 1. WV Assessments has a free searchable database of West Virginia real estate tax assessments, covering current and past years. All property is reappraised every three years; annual adjustments are made to assessments for property with a change of value. West Virginia does not impose an inheritance tax. Because of the phase-out of the federal estate tax credit, West Virginia's estate tax is not imposed on estates of persons who died on or after January 1, 2005.[109]
+
+The largest private employers in West Virginia, as of March 2011, were:[110]
+
+West Virginia governor Tomblin's proposed 2014–15 budget submitted in January 2014 had an estimated budget gap of $146–$265 million, and halfway through the 2013–14 fiscal year, tax revenues were $82 million short.[111] The West Virginia Legislature in March 2014 passed its budget bill, taking $147 million from the Rainy Day Fund to balance the 2015 budget.[112] Governor Tomblin's deputy chief of staff Jason Pizatella, after the state legislature passed the budget, said West Virginia is expecting another dismal budget in 2016 and could need $150–170 million to balance the next year's budget.[113]
+
+West Virginia coal exports declined 40% in 2013—a loss of $2.9 billion and overall total exports declined 26%.[114] West Virginia ranked last in the Gallup Economic Index for the fourth year running. West Virginia's score was −44, or a full 17 points lower than the average of −27 for the other states in the bottom ten.[115] West Virginia ranked 48th in the CNBC "Top States for Business 2013" based on measures of competitiveness such as economy, workforce and cost of living—ranking among the bottom five states for the last six years running.[116] West Virginia ranked 49th in the 2014 State New Economy Index, and has ranked in the bottom three states since 1999. West Virginia ranked last or next-to-last in critical indicators such as Workforce Education, Entrepreneurial Activity, High-Tech Jobs, and Scientists and Engineers.[117]
+
+On January 9, 2014, a chemical spill contaminated the water supply of 300,000 people in nine West Virginia counties near Charleston. According to Bloomberg News, lost wages, revenue, and other economic harm from the chemical spill could top $500 million.[118][needs update] and West Virginia's Marshall University Center for Business and Economic Research estimated that about $61 million was lost by businesses in the first four days alone after the spill.[119]
+
+In 2012, West Virginia's Gross Domestic Product (GDP) grew by 3.3%.[120] The state issued a report highlighting the state's GDP as indicating a fast-growing economy, but did not address employment indicators.[121] In 2009–2013, the U.S. real GDP increased 9.6% and total employment increased 3.9%. In West Virginia during the same time period, its real GDP increased about 11%, while total employment decreased by 1,000 jobs from 746,000 to 745,000.
+
+In 2013, West Virginia ranked last in the nation with an employment-to-population ratio of only 50%, compared to the national average of 59%.[122] The state lost 5,600 jobs in its labor force in four critical economic sectors: construction (1,900), manufacturing (1,100), retail (1,800), and education (800), while gaining just 400 in mining and logging.[123] The state's Civilian Labor Force dropped by 15,100.[124]
+
+Personal income growth in West Virginia during 2013 was only 1.5%—the lowest in the nation—and about half the national average (2.6%).[125] Overall income growth in West Virginia in the last thirty years has been only 13%—about a third the national average (37%). Wages of the impoverished bottom 1% income earners decreased by 3%, compared to the national average, which increased 19%.[126]
+
+West Virginia's poverty rate is one of the highest in the nation. 2017 estimates indicate that 19% of the state's population lives in poverty, exceeding the national average of 13%.[127]
+
+The West Virginia teachers' strike in 2018 inspired teachers in other states to take similar action.[128]
+
+United Van Lines 37th Annual Migration Study showed in 2013 that 60% more people moved out of the Mountain State than moved in.[129] West Virginia's population is expected to decline by more than 19,000 residents by 2030, and West Virginia could lose one of its three seats in the United States House of Representatives.[130] West Virginia is the only state where death rates exceeds birth rates. During 2010–2013, about 21,000 babies per year were born in West Virginia, but over these three years West Virginia had 3,000 more deaths than births.[131]
+
+Gallup-Healthways annual "State of American Well-Being" rankings reports that 1,261 concerned West Virginians rated themselves as "suffering" in categories such as Quality of Life, Physical Health, and Access to Basic Needs. Overall, West Virginia citizens rated themselves as being more miserable than people in all other states—for five years running.[132] In addition, the Gallup Well-Being Index for 2013 ranked Charleston, the state capital, and Huntington last and next-to-last out of 189 U.S. Metropolitan Statistical Areas.[133]
+
+The Annie E. Casey Foundation's National Index of Children's Progress ranked West Virginia 43rd in the nation for all kids, and last for white kids.[134] The Annie E. Casey Foundation's 2013 KIDS COUNT Data Book also ranked West Virginia's education system 47th in the nation for the second straight year.[135] Charleston, West Virginia has the worst divorce rate among 100 cities in the nation. Stephen Smith, the executive director of the West Virginia Healthy Kids and Families Coalition, said poor employment prospects are to blame: "The pressure to make a good living puts strain on a marriage, and right now it is infinitely harder to make a living here than it was 40 years ago."[136]
+
+United Health Foundation's "America's Health Rankings" for 2013 found that Americans are making considerable progress in key health measures. West Virginia, however, ranked either last or second-to-last in twenty categories, including cancer, child immunization, diabetes, disabilities, drug deaths, teeth loss, low birth weight, missed work days due to health, prescription drug overdose, preventable hospitalizations, and senior clinical care.[137] Wisconsin Population Health Institute annual "Health Rankings" for 2012 showed West Virginia spends $9,671 per capita on health care annually. El Salvador spends just $467, yet both have the same life expectancy.[138] In 2012, according to the Census Bureau, West Virginia was the only state where death rates exceeds birth rates. During 2010–2013, about 21,000 babies per year were born in West Virginia, but there were 24,000 deaths.[131] In demographics, this is called a "net mortality society".[139]
+
+The National Center for Health Statistics says national birth rates for teenagers are at historic lows—during 2007–2010, teen birth rates fell 17% nationally;. West Virginia, however, ranked last with a 3% increase in birth rates for teenagers.[140] A study by West Virginia's Marshall University showed that 19% of babies born in the state have evidence of drug or alcohol exposure.[141] This is several times the national rate, where studies show that about 5.9% of pregnant women in the U.S. use illicit drugs, and about 8.5% consume any alcohol.[142] An Institute for Health Policy Research study determined that mortality rates in Appalachia are correlated with coal production. In twenty West Virginia coal counties mining more than a million tons of coal per year and having a total population of 850,000, there are about 10,100 deaths per year, with 1,400 of those statistically attributed to deaths from heart, respiratory and kidney disease from living in an Appalachian coal county.[143]
+
+In 2015, McDowell County had the highest rate of drug-induced deaths of any county in the United States, with a rate of 141 deaths per 100,000 people. Four of the five counties with the highest rates of drug-induced deaths are in West Virginia (McDowell, Wyoming, Cabell and Raleigh Counties).[144]
+
+in Charleston
+
+The West Virginia Legislature is bicameral. It consists of the House of Delegates and the Senate, both housed in the West Virginia State Capitol. It is a citizen's legislature, meaning that legislative office is not a full-time occupation, but rather a part-time position. Consequently, the legislators often hold a full-time job in their community of residence.
+
+Typically, the legislature is in session for 60 days between January and early April. The final day of the regular session ends in a bewildering fury of last-minute legislation to meet a constitutionally imposed midnight deadline. During the remainder of the year, monthly interim sessions are held in preparation for the regular session. Legislators also gather periodically for 'special' sessions when called by the governor.
+
+The title of Lieutenant Governor is assigned by statute to the senate president.
+
+The governor, elected every four years on the same day as the U.S. presidential election, is sworn in during the following January.
+
+Governors of West Virginia can serve two consecutive terms but must sit out a term before serving a third term in office.
+
+The title of Lieutenant Governor is assigned by statute to the senate president.
+
+West Virginia is one of nineteen states that do not have a death penalty, and it is the only state in the southeastern United States to have abolished it.
+
+For the purpose of courts of general jurisdiction, the state is divided into 31 judicial circuits. Each circuit is made up of one or more counties. Circuit judges are elected in non-partisan elections to serve eight-year terms.
+
+West Virginia's highest court is the Supreme Court of Appeals. The Supreme Court of Appeals of West Virginia is the busiest appellate court of its type in the United States. West Virginia is one of 11 states with a single appellate court. The state constitution allows for the creation of an intermediate court of appeals, but the Legislature has never created one. The Supreme Court is made up of five justices, elected in non-partisan elections to 12-year terms.
+
+West Virginia is an alcoholic beverage control state. However, unlike most such states, it does not operate retail outlets, having exited that business in 1990. It retains a monopoly on wholesaling of distilled spirits only.
+
+At the state level, West Virginia's politics were largely dominated by the Democratic Party from the Great Depression through the 2000s. This was a legacy of West Virginia's very strong tradition of union membership.[145] After the 2014 midterm elections Democrats controlled the governorship, the majority of statewide offices, and one U.S. Senate seat, while Republicans held one U.S. Senate seat, all three of the state's U.S. House seats, and a majority in both houses of the West Virginia Legislature. In the 2016 elections, the Republicans held on to their seats and made gains in the State Senate and gained three statewide offices.[146][147]
+
+Since 2000, West Virginians have supported the Republican candidate in every presidential election. The state is regarded as a "deep red" state at the federal level.[145][148] In 2012 Republican Mitt Romney won the state, defeating Democrat Barack Obama with 62% of the vote to 35% for Obama. In the 2016 presidential election, Republican Donald Trump won the state with 67.86% of the popular vote, with West Virginia being the second-highest percentage voting for Trump of any state.[149]
+
+Evangelical Christians comprised 52% of the state's voters in 2008.[150] A poll in 2005 showed that 53% of West Virginia voters are anti-abortion, the seventh highest in the country.[151] A 2014 poll by Pew Research found that 35% of West Virginians supported legal abortion in "all or most cases" while 58% wanted it to be banned "in all or most cases".[152] A September 2011 Public Policy Polling survey found that 19% of West Virginia voters thought same-sex marriage should be legal, while 71% thought it should be illegal and 10% were not sure. A separate question on the same survey found that 43% of West Virginia voters supported the legal recognition of same-sex couples, with 17% supporting same-sex marriage, 26% supporting civil unions but not marriage, 54% favoring no legal recognition and 3% not sure.[153] In 2008, 58% favored troop withdrawal from Iraq while just 32% wanted troops to remain.[154] On fiscal policy in 2008, 52% said raising taxes on the wealthier individuals would benefit the economy, while 45% disagreed.[155]
+
+The West Virginia Department of Commerce is a government agency responsible for overseeing West Virginia's economy, workforce, natural resources, and tourism, the department oversees nine subsidiary agencies.[156]
+
+Highways form the backbone of transportation systems in West Virginia, with over 37,300 miles (60,000 km) of public roads in the state.[157] Airports, railroads, and rivers complete the commercial transportation modes for West Virginia. Commercial air travel is facilitated by airports in Charleston, Huntington, Morgantown, Beckley, Lewisburg, Clarksburg, and Parkersburg. All but Charleston and Huntington are subsidized by the federal Department of Transportation's Essential Air Service program. The cities of Charleston, Huntington, Beckley, Wheeling, Morgantown, Clarksburg, Parkersburg and Fairmont have bus-based public transit systems.
+
+West Virginia University in Morgantown boasts the PRT (personal rapid transit) system, the state's only single-rail public transit system. Developed by Boeing, the WVU School of Engineering and the Department of Transportation, it was a model for low-capacity light transport designed for smaller cities. Recreational transportation opportunities abound in West Virginia, including hiking trails,[158] rail trails,[159] ATV off-road trails,[160] white water rafting rivers,[161] and two tourist railroads, the Cass Scenic Railroad[162] and the Potomac Eagle Scenic Railroad.[163]
+
+West Virginia is crossed by seven Interstate Highways. I-64 enters the state near White Sulphur Springs in the mountainous east, and exits for Kentucky in the west, near Huntington. I-77 enters from Virginia in the south, near Bluefield. It runs north past Parkersburg before it crosses into Ohio. I-64 and I-77 between Charleston and Beckley are merged as toll road known as the West Virginia Turnpike, which continues as I-77 alone from Beckley to Princeton. It was constructed beginning in 1952 as a two lane road, but rebuilt beginning in 1974 to Interstate standards. Today almost nothing of the original construction remains. I-68's western terminus is in Morgantown. From there it runs east into Maryland. At the I-68 terminus in Morgantown, it meets I-79, which enters from Pennsylvania and runs through the state to its southern terminus in Charleston. I-70 briefly runs through West Virginia, crossing the northern panhandle through Wheeling, while I-470 is a bypass of Wheeling (making Wheeling among the smallest cities with an interstate bypass). I-81 also briefly runs in West Virginia through the Eastern Panhandle where it goes through Martinsburg.
+
+The interstates are supplemented by roads constructed under the Appalachian Corridor system. Four Corridors are complete. Corridor D, carrying US 50, runs from the Ohio River, and I-77, at Parkersburg to I-79 at Clarksburg. Corridor G, carrying US 119, runs from Charleston to the Kentucky border at Williamson. Corridor L, carrying US 19, runs from the Turnpike at Beckley to I-79 near Sutton (and provides a short cut of about 40 miles (64 km) and bypasses Charleston's urban traffic for traveler heading to and from Florida). Corridor Q, carrying US 460, runs through Mercer County, entering the state from Giles County, Virginia and then reentering Virginia at Tazewell County.
+
+Work continues on the long delayed Corridor H, which will carry US 48 from Weston to the Virginia line near Wardensville. As of 2018, a section from Weston to Kerens just past Elkins, and another section from Wardensville to Davis are complete. Other projects under development are a four-lane upgrade of US 35 from Scott Depot to the Ohio River at Point Pleasant, which is about two-thirds complete; a four lane upgrade of WV 10 from Logan to Man and then of WV 80 from Man to Gilbert, which is about half completed; and four lane upgrades to US 52 from Bluefield to Williamson, known as the "King Coal Highway" and from Williamson to Huntington, known as the "Tolsia Highway" which are many years from completion. A project known as the "Coalfields Expressway" is also ongoing, and will carry US 121 from Beckley west across Raleigh, Wyoming, and McDowell counties, entering Virginia near Bishop.
+
+Rail lines in the state used to be more prevalent, but many lines have been discontinued because of increased automobile traffic. Many old tracks have been converted to rail trails for recreational use, although the coal producing areas still have railroads running at near capacity. Amtrak's Cardinal roughly parallels I-64's path through the state. MARC trains serve commuters in the eastern panhandle. In 2006 Norfolk Southern along with the West Virginia and U.S. Government approved a plan to modify many of the rail tunnels in West Virginia, especially in the southern half of the state, to allow for double stacked cars (see inter-modal freight). This is expected to also help bring economic growth to the southern half of the state. An Intermodal Freight Facility is located at Prichard, just south of Huntington.
+
+Because of the mountainous nature of the entire state, West Virginia has several notable tunnels and bridges. The most famous of these is the New River Gorge Bridge, which was at a time the longest steel single-arch bridge in the world with a 3,031-foot (924 m) span. The bridge is also pictured on the West Virginia state quarter. The Fort Steuben Bridge (Weirton-Steubenville Bridge) was at the time of its construction one of only three cable-stayed steel girder trusses in the United States. "The Veterans Memorial Bridge was designed to handle traffic from the Fort Steuben Bridge as well as its own traffic load", to quote the Weirton Daily Times newspaper.[164] The 80-year-old Fort Steuben Bridge (Weirton-Steubenville Bridge) was permanently closed on January 8, 2009. The Wheeling Suspension Bridge was the first bridge built across the Ohio River in 1849 and for a time was the longest suspension bridge in the world. It is still the oldest vehicular suspension bridge in the United States still in use.
+
+Originally, the state capital was in Wheeling (1863 to 1870). It was then moved to Charleston, a more central city (1870 to 1875). However it was returned to Wheeling in 1875, until the capitol burned down in 1885. It was moved back to Charleston in 1885, and it has been there since.[165]
+
+Morgantown
+
+Wheeling
+
+Beckley
+
+Fairmont
+
+Martinsburg
+
+West Virginia is home to college sports teams from two schools—West Virginia and Marshall—that play in NCAA Division I. West Virginia is also home to several professional minor league baseball, football, soccer, and other sports teams.
+
+West Virginia's folk heritage is a part of the Appalachian folk music tradition, and includes styles of fiddling, ballad singing, and other styles that draw on Scots-Irish music. Camp Washington-Carver, a Mountain Cultural Arts Center located at Clifftop in Fayette County, hosts an annual Appalachian String Band Festival.[169] The Capitol Complex in Charleston hosts The Vandalia Gathering, where traditional Appalachian musicians compete in contests and play in impromptu jam sessions and evening concerts over the weekend.[170] The Augusta Heritage Center sponsored by Davis & Elkins College in Elkins in Randolph County produces the annual Augusta Heritage Festival, which includes intensive week-long workshops in the summer that help preserve Appalachian heritage and traditions.[171]
+
+The West Virginia Symphony Orchestra was founded in 1939, as the Charleston Civic Orchestra, before becoming the Charleston Symphony Orchestra in 1943. The first conductor was William R. Wiant, followed by the conductor Antonio Modarelli, who was written about in the November 7, 1949 Time Magazine for his composition of the River Saga, a six-section program piece about the Kanawha River according to the Charleston Gazette's November 6, 1999 photo essay, "Snapshots of the 20th Century".[172] Before coming to Charleston, Modarelli had conducted the Wheeling Symphony Orchestra and the Philadelphia Orchestra, according to the orchestra's website.[173]
+
+The Pulitzer Prize-winning 20th-century composer George Crumb was born in Charleston and earned his bachelor's degree there before moving outside the state. There had also been a series of operatic style concerts performed in Wheeling during mid-century as well.
+
+The West Virginia Cultural Center in Charleston[174] is home to the West Virginia Division of Culture and History,[175] which helps underwrite and coordinate a large number of musical activities. The center is also home to Mountain Stage, an internationally broadcast live-performance music radio program established in 1983 which is carried by many affiliates of National Public Radio.[176] The program also travels to other venues in the state such as the West Virginia University Creative Arts Center in Morgantown.[177]
+
+The center hosts concerts sponsored by the Friends of Old Time Music and Dance, which brings an assortment of acoustic roots music to West Virginians.[178] The center also hosts the West Virginia Dance Festival, which features classical and modern dance.[179]
+
+Huntington's historic Keith-Albee Theatre, built by brothers A.B. and S.J. Hyman, was originally opened to the public on May 7, 1928, and hosts a variety of performing arts and music attractions. The theatre was eventually gifted to Marshall University and is currently going through renovation to restore it to its original splendor.
+
+Every summer Elkins hosts the Augusta Heritage Festival, which brings folk musicians from around the world.[180] The town of Glenville has long been home to the annual West Virginia State Folk Festival.[181]
+
+The Mountaineer Opera House in Milton hosts a variety of musical acts.
+
+John Denver's hit song "Take Me Home, Country Roads" describes the experience of driving through West Virginia. The song mentions the Shenandoah River and the Blue Ridge Mountains, both features traversing the easternmost extremity of the state's "eastern panhandle", in Jefferson County. On March 8, 2014, West Virginia governor Earl Ray Tomblin signed House Concurrent Resolution 40 naming "Take Me Home, Country Roads" the fourth official state song of West Virginia.
+
+Symphony Sunday is an annual event hosted by the West Virginia Symphony Orchestra held in June. It is a day full day of music by community groups, food, and family fun, culminating in a free performance by the West Virginia Symphony Orchestra with a fireworks display following. The event began in 1982 and is held on the front lawn of the University of Charleston.
+
+The Daily Mail Kanawha County Majorette and Band Festival is West Virginia's longest running music festival. It is for the eight public high schools in Kanawha County. The festival began in 1947. It is held at the University of Charleston Stadium at Laidley Field in downtown Charleston.
+
+Former state parks: Booker T. Washington · Grandview · Grave Creek Mound · Mingo Oak · Mont Chateau · Morgan Morgan Monument
+
+Coordinates: 39°00′N 80°30′W / 39°N 80.5°W / 39; -80.5

en/6007.html.txt

@@ -0,0 +1,297 @@
+
+
+West Virginia (/vərˈdʒɪniə/ (listen)) is a state located in the Appalachian region of the Southern United States, though it is also considered to be a part of the Mid-Atlantic Southeast Region.[Note 1] It is bordered by Pennsylvania to the northeast, Maryland to the east and northeast, Virginia to the southeast, Kentucky to the southwest, and Ohio to the northwest. West Virginia is the 41st largest state by area and ranks 38th in population, with around 1.791 million residents. The capital and largest city is Charleston.
+
+West Virginia became a state following the Wheeling Conventions of 1861, at the start of the American Civil War. Delegates from the Unionist counties of northwestern Virginia decided to break away from Virginia, which also included secessionist counties in the new state.[6] West Virginia was admitted to the Union on June 20, 1863, and was a key border state during the war. It was the only state to form by separating from a Confederate state, the first to separate from any state since Maine separated from Massachusetts, and was one of two states (along with Nevada) admitted to the Union during the American Civil War. While a portion of its residents held slaves, most of the residents were yeoman farmers, and the delegates provided for gradual abolition of slavery in the new state Constitution and the state's legislature completely abolished slavery before the end of the war.
+
+The northern panhandle extends adjacent to Pennsylvania and Ohio, with the West Virginia cities of Wheeling and Weirton just across the border from the Pittsburgh metropolitan area, while Bluefield is less than 70 miles (110 km) from North Carolina. Huntington in the southwest is close to the states of Ohio and Kentucky, while Martinsburg and Harpers Ferry in the Eastern Panhandle region are considered part of the Washington metropolitan area, in between the states of Maryland and Virginia. The unique position of West Virginia means it is often included in several U.S. geographical regions, including the Mid-Atlantic, the Upland South, and the Southeastern United States. It is the only state that is entirely within the area served by the Appalachian Regional Commission; the area is commonly defined as "Appalachia".[7]
+
+The state is noted for its mountains and rolling hills, its historically significant logging and coal mining industries, and its political and labor history. It is also known for a wide range of outdoor recreational opportunities, including skiing, whitewater rafting, fishing, hiking, backpacking, mountain biking, rock climbing, and hunting.
+
+Many ancient man-made earthen mounds from various prehistoric mound builder cultures survive, especially in the areas of present-day Moundsville, South Charleston, and Romney. The artifacts uncovered in these give evidence of village societies. They had a tribal trade system culture that crafted cold-worked copper pieces.
+
+In the 1670s during the Beaver Wars, the powerful Iroquois, five allied nations based in present-day New York and Pennsylvania, drove out other American Indian tribes from the region in order to reserve the upper Ohio Valley as a hunting ground. Siouan language tribes, such as the Moneton, had previously been recorded in the area.
+
+A century later, the area now identified as West Virginia was contested territory among Anglo-Americans as well, with the colonies of Pennsylvania and Virginia claiming territorial rights under their colonial charters to this area before the American Revolutionary War. Some speculative land companies, such as the Vandalia Company,[8] and later the Ohio Company and Indiana Company, tried to legitimize their claims to land in parts of West Virginia and present day Kentucky, but failed. This rivalry resulted in some settlers petitioning the Continental Congress to create a new territory called Westsylvania. With the federal settlement of the Pennsylvania and Virginia border dispute, creating Kentucky County, Virginia, Kentuckians "were satisfied [...] and the inhabitants of a large part of West Virginia were grateful."[9]
+
+The Crown considered the area of West Virginia to be part of the British Virginia Colony from 1607 to 1776. The United States considered this area to be the western part of the state of Virginia (which was commonly referred as Trans-Allegheny Virginia) from 1776 to 1863, before the formation of West Virginia. Its residents were discontented for years with their position in Virginia, as the government was dominated by the planter elite of the Tidewater and Piedmont areas. The legislature had electoral malapportionment, based on the counting of slaves toward regional populations, and the western white residents were underrepresented in the state legislature. More subsistence and yeoman farmers lived in the west and they were generally less supportive of slavery, although many counties were divided on their support. The residents of this area became more sharply divided after the planter elite of eastern Virginia voted to secede from the Union during the Civil War.
+
+Residents of the western and northern counties set up a separate government under Francis Pierpont in 1861, which they called the Restored Government. Most voted to separate from Virginia, and the new state was admitted to the Union in 1863. In 1864 a state constitutional convention drafted a constitution, which was ratified by the legislature without putting it to popular vote. West Virginia abolished slavery by a gradual process and temporarily disenfranchised men who had held Confederate office or fought for the Confederacy.
+
+West Virginia's history has been profoundly affected by its mountainous terrain, numerous and vast river valleys, and rich natural resources. These were all factors driving its economy and the lifestyles of its residents, who tended to live in many small, relatively isolated communities in the mountain valleys.
+
+A 2010 analysis of a local stalagmite revealed that Native Americans were burning forests to clear land as early as 100 BCE.[10] Some regional late-prehistoric Eastern Woodland tribes were more involved in hunting and fishing, practicing the Eastern Agricultural Complex gardening method which used fire to clear out underbrush from certain areas. Another group progressed to the more time-consuming, advanced companion crop fields method of gardening. Also continuing from ancient indigenous people of the state, they cultivated tobacco through to early historic times. It was used in numerous social and religious rituals.
+
+"Maize (corn) did not make a substantial contribution to the diet until after 1150 BP", to quote Mills (OSU 2003).[full citation needed] Eventually, tribal villages began depending on corn to feed their turkey flocks, as Kanawha Fort Ancients practiced bird husbandry. The local Indians made corn bread and a flat rye bread called "bannock" as they emerged from the protohistoric era. A horizon extending from a little before the early 18th century is sometimes called the acculturating Fireside Cabin culture. Trading posts were established by European traders along the Potomac and James rivers.
+
+Tribes that inhabited West Virginia as of 1600 were the Siouan Monongahela Culture to the north, the Fort Ancient culture along the Ohio River from the Monongahela to Kentucky and extending an unknown distance inland,[11] and the Eastern Siouan Tutelo and Moneton tribes in the southeast. There was also the Iroquoian Susquehannock in the region approximately east of the Monongahela River and north of the Monongahela National Forest, a possible tribe called the Senandoa, or Shenandoah, in the Shenandoah Valley and the easternmost tip of the state may have been home to the Manahoac people. The Monongahela may have been the same as a people known as the Calicua, or Cali.[12] The following may have also all been the same tribe—Moneton, Moheton, Senandoa, Tomahitan.
+
+During the Beaver Wars, other tribes moved into the region. There was the Iroquoian Tiontatecaga (also Little Mingo, Guyandotte),[13] who seem to have split off from the Petun after they were defeated by the Iroquois. They eventually settled somewhere between the Kanawha and Little Kanawha Rivers. During the 1750s, when the Mingo Seneca seceded from the Iroquois and returned to the Ohio River Valley, they contend that this tribe merged with them. The Shawnee arrived as well, but were primarily stationed within former Monongahela territory approximately until 1750, however they did extend their influence throughout the Ohio River region. They were the last Native tribe of West Virginia and were driven out by the United States during the Shawnee Wars (1811–1813). The Erie, who were chased out of Ohio around 1655, are now believed to be the same as the Westo, who invaded as far as South Carolina before being destroyed in the 1680s. If so, their path would have brought them through West Virginia. The historical movement of the Tutelo,[14] as well as Carbon dating for the Fort Ancients seem to correspond with the given period of 1655–1670 as the time of their removal.[11] The Susquehannocks were original participants of the Beaver Wars, but were cut off from the Ohio River by the Iroquois around 1630 and found themselves in dire straits. From disease, constant warfare and an inability to provide for themselves financially, they began to collapse and moved further and further east, to the Susquehanna River of Eastern Pennsylvania.[15] The Manahoac were probably forced out in the 1680s, when the Iroquois began to invade Virginia.[16] The Siouan tribes there moved into North Carolina and later returned as one tribe, known as the Eastern Blackfoot, or Christannas.[17]
+
+The Westo did not secure the territory they conquered. Before they were even gone, displaced natives from the south flooded into freshly conquered regions and took them over.[18] These became known as the Shattaras, or West Virginia Cherokees. They took in and merged with the Monetons, who began to refer to themselves as the Mohetons. The Calicua also began to refer to themselves as Cherokees soon after, showing an apparent further merger. These Shattaras were closely related to the tribes which formed to the south in the aftermath of the Westo—the Yuchi and Cherokee. From 1715–1717, the Yamasee War sprang up. The Senandoa allegedly sided with the Yuchi and were destroyed by Yamasee allies.[19] Therefore, if the Senandoa were the same tribe as the Moneton, this would mean the collapse of Shattara-Moneton culture. Another tribe who appeared in the region were the Canaragay, or Kanawha.[20] They later migrated to Maryland and merged into colonial culture.
+
+In 1671, General Abraham Wood, at the direction of Royal Governor William Berkeley of the Virginia Colony, sent a party from Fort Henry led by Thomas Batts and Robert Fallam to survey this territory. They were the first Europeans recorded as discovering Kanawha Falls. Some sources state that Governor Alexander Spotswood's 1716 Knights of the Golden Horseshoe Expedition (for which the state's Golden Horseshoe Competition for 8th graders was named) had penetrated as far as Pendleton County; however, modern historians interpret the original accounts of the excursion as suggesting that none of the expedition's horsemen ventured much farther west of the Blue Ridge Mountains than Harrisonburg, Virginia. John Van Metre, an Indian trader, penetrated into the northern portion in 1725. The same year, German settlers from Pennsylvania founded New Mecklenburg, the present Shepherdstown, on the Potomac River, and others followed.[21]
+
+King Charles II of England, in 1661, granted to a company of gentlemen the land between the Potomac and Rappahannock rivers, known as the Northern Neck. Thomas Fairfax, 6th Lord Fairfax of Cameron ultimately took possession of this grant, and in 1746, a stone was erected at the source of the North Branch Potomac River to mark the western limit of his grant. A considerable part of this land was surveyed by the young George Washington between 1748 and 1751. The diary kept by Washington recorded that there were already many squatters, largely of German origin, along the South Branch Potomac River.[22]
+
+Christopher Gist, a surveyor in the employ of the first Ohio Company, which was composed chiefly of Virginians, explored the country along the Ohio River north of the mouth of the Kanawha River between 1751 and 1752. The company sought to have a fourteenth colony established with the name "Vandalia". Many settlers crossed the mountains after 1750, though they were hindered by Native American resistance. Few Native Americans lived permanently within the present limits of the state, but the region was a common hunting ground, crossed by many trails. During the French and Indian War (the North American front of the Seven Years' War in Europe), Indian allies of the French nearly destroyed the scattered British settlements.[23]
+
+Shortly before the American Revolutionary War, in 1774 the Crown Governor of Virginia John Murray, 4th Earl of Dunmore, led a force over the mountains. A body of militia under then-Colonel Andrew Lewis dealt the Shawnee Indians, under Hokoleskwa (or "Cornstalk"), a crushing blow during the Battle of Point Pleasant at the junction of the Kanawha and the Ohio rivers.[23] At the Treaty of Camp Charlotte concluding Dunmore's War, Cornstalk agreed to recognize the Ohio River as the new boundary with the "Long Knives". By 1776, however, the Shawnee had returned to war, joining the Chickamauga, a band of Cherokee known for the area where they lived.[citation needed] Native American attacks on settlers continued until after the American Revolutionary War. During the war, the settlers in western Virginia were generally active Whigs and many served in the Continental Army.[23] However, Claypool's Rebellion of 1780–1781, in which a group of men refused to pay taxes imposed by the Continental Army, showed war-weariness in what became West Virginia.
+
+Social conditions in western Virginia were entirely unlike those in the eastern portion of the state. The population was not homogeneous, as a considerable part of the immigration came by way of Pennsylvania and included Germans, Protestant Scotch-Irish, and settlers from the states farther north. Counties in the east and south were settled mostly by eastern Virginians. During the American Revolution, the movement to create a state beyond the Alleghenies was revived and a petition for the establishment of "Westsylvania" was presented to Congress, on the grounds that the mountains presented an almost impassable barrier to the east. The rugged nature of the country made slavery unprofitable, and time only increased the social, political, economic, and cultural differences (see Tuckahoe-Cohee) between the two sections of Virginia.[23]
+
+In 1829, a constitutional convention met in Richmond to consider reforms to Virginia's outdated constitution. Philip Doddridge of Brooke County championed the cause of western Virginians who sought a more democratic frame of government.[24] However, western reforms were rejected by leaders from east of the Alleghenies who "clung to political power in an effort to preserve their plantation lifestyles dependent on enslaving blacks".[25] Virginia leaders maintained a property qualification for suffrage effectively disenfranchising poorer farmers in the west whose families did much of the farm-work themselves. In addition, the 1829–1830 convention gave the slave-holding counties the benefit of three-fifths of their slave population in apportioning the state's representation in the U.S. House of Representatives. As a result, every county west of the Alleghenies except one voted to reject the constitution, which nevertheless passed because of eastern support.[23] Failure of the eastern planter elite to make constitutional reforms exacerbated existing east–west sectionalism in Virginia and contributed to Virginia's later division.[26]
+
+The Virginia Constitutional Convention of 1850–51, the Reform Convention, addressed a number of issues important to western Virginians. It extended the vote to all white males 21 years or older. The governor, lieutenant governor, the judiciary, sheriffs, and other county officers were to be elected by public vote. The composition of the General Assembly was changed. Representation in the house of delegates was apportioned on the basis of the census of 1850, counting whites only. The Senate representation was arbitrarily fixed at 50 seats, with the west receiving twenty, and the east thirty senators. This was made acceptable to the west by a provision that required the General Assembly to reapportion representation on the basis of white population in 1865, or else put the matter to a public referendum. But the east also gave itself a tax advantage in requiring a property tax at true and actual value, except for slaves. Slaves under the age of 12 years were not taxed and slaves over that age were taxed at only $300, a fraction of their true value. Small farmers, however, had all their assets, animals, and land taxed at full value. Despite this tax and the lack of internal improvements in the west, the vote was 75,748 for and 11,063 against the new Constitution. Most of the opposition came from delegates from eastern counties, who did not like the compromises made for the west.[27]
+
+Given these differences, many in the west had long contemplated a separate state. In particular, men such as lawyer Francis H. Pierpont from Fairmont, had long chafed under the political domination of the Tidewater and Piedmont slave-holders. In addition to differences over the abolition of slavery, he and allies felt the Virginia government ignored and refused to spend funds on needed internal improvements in the west, such as turnpikes and railroads.[28]
+
+West Virginia was the only state in the Union to separate from a Confederate state (Virginia) during the American Civil War.[30] In Richmond on April 17, 1861, the Virginia Secession Convention of 1861 voted to secede from the Union, but of the 49 delegates from the northwestern corner (which ultimately became West Virginia) only 17 voted in favor of the Ordinance of Secession, while 30 voted against[31] (with two abstentions).[32] Almost immediately after that vote, a mass meeting at Clarksburg recommended that each county in northwestern Virginia send delegates to a convention to meet in Wheeling on May 13, 1861. When this First Wheeling Convention met, 425 delegates from 25 counties were present, though more than one-third of the delegates were from the northern panhandle area.[33] Soon, there was a division of sentiment.[23]
+
+Some delegates led by John S. Carlile favored the immediate formation of a new state, while others led by Waitman Willey argued that, as Virginia's secession had not yet been passed by the required referendum (as happened on May 23), such action would constitute revolution against the United States.[34] The convention decided that if Virginians adopted the secession ordinance (of which there was little doubt), another convention including the members-elect of the legislature would meet in Wheeling in June 1861. On May 23, 1861, secession was ratified by a large majority in Virginia as a whole, but in the western counties 34,677 voted against and 19,121 voted for the Ordinance.[35]
+
+The Second Wheeling Convention met as agreed on June 11 and declared that, since the Secession Convention had been called without popular consent, all its acts were void and that all who adhered to it had vacated their offices.[23] The Wheeling Conventions, and the delegates themselves, were never actually elected by public ballot to act on behalf of western Virginia.[36] Of its 103 members, 33 had been elected to the Virginia General Assembly[37] on May 23. This included some hold-over state senators whose four-year terms had begun in 1859, and some who vacated their offices to convene in Wheeling. Other members "were chosen even more irregularly—some in mass meetings, others by county committee, and still others were seemingly self-appointed".[38] An act for the reorganization of the government was passed on June 19. The next day convention delegates chose Francis H. Pierpont as governor of Virginia, and elected other officers to a rival state government and two U.S. senators (Willey and Carlile) to replace secessionists before adjourning. The federal government in Washington, D.C. promptly recognized the new government and seated the two new senators. Thus, there were two state governments in Virginia: one pledging allegiance to the United States and one to the Confederacy.[23]
+
+The second Wheeling Convention had recessed until August 6, then reassembled on August 20 and called for a popular vote on the formation of a new state and for a convention to frame a constitution if the vote should be favorable. At the October 24, 1861 election, 18,408 votes were cast for the new state and only 781 against.[23] The election results were questioned, since the Union army then occupied the area and Union troops were stationed at many of the polls to prevent Confederate sympathizers from voting.[39] This was also election day for local offices, and elections were also held in camps of Confederate soldiers, who elected rival state officials, such as Robert E. Cowan. Most pro-statehood votes came from 16 counties around the Northern panhandle.[40] Over 50,000 votes had been cast on the Ordinance of Secession, yet the vote on statehood garnered little more than 19,000.[41] In Ohio County, home to Wheeling, only about a fourth of the registered voters cast votes.[42] In most of what would become West Virginia, there was no vote at all, as two-thirds of the territory of West Virginia had voted for secession and county officers remained loyal to Richmond. Votes recorded from pro-secession counties were mostly cast elsewhere by Unionist refugees from these counties.[43]
+
+Despite that controversy, delegates (including many Methodist ministers) met to write a new Constitution for the new state, beginning on November 26, 1861. During that constitutional convention, a Mr. Lamb of Ohio County and a Mr. Carskadon claimed that in Hampshire County, out of 195 votes only 39 were cast by citizens of the state; the rest were cast illegally by Union soldiers.[44] One of the key figures was Rev. Gordon Battelle, who also represented Ohio County, and who proposed resolutions to establish public schools, as well as to limit movement of slaves into the new state, and to gradually abolish slavery. The education proposal succeeded, but the convention tabled the slavery proposals before finishing its work on February 18, 1862. The new constitution was more closely modeled on that of Ohio than of Virginia, adopting a township model of government rather than the "courthouse cliques" of Virginia which Carlile criticized, and a compromise demanded by the Kanawha region (Charleston lawyers Benjamin Smith and Brown) allowed counties and municipalities to vote subsidies for railroads or other improvement organizations.[45] The resulting instrument was ratified (18,162 for and 514 against) on April 11, 1862.
+
+On May 13, 1862 the state legislature of the reorganized government approved the formation of the new state. An application for admission to the Union was made to Congress, introduced by Senator Waitman Willey of the Restored Government of Virginia. However, Sen. Carlile sought to sabotage the bill, first trying to expand the new state's boundaries to include the Shenandoah Valley, and then to defeat the Willey amendment at home.[46] On December 31, 1862, an enabling act was approved by President Abraham Lincoln admitting West Virginia, on the condition that a provision for the gradual abolition of slavery be inserted in its constitution[23] (as Rev. Battelle had urged in the Wheeling Intelligencer and also written to Lincoln). While many felt West Virginia's admission as a state was both illegal and unconstitutional, Lincoln issued his Opinion on the Admission of West Virginia finding that "the body which consents to the admission of West Virginia is the Legislature of Virginia", and that its admission was therefore both constitutional and expedient.[47]
+
+The convention was reconvened on February 12, 1863, and the abolition demand of the federal enabling act was met. The revised constitution was adopted on March 26, 1863 and on April 20, 1863, President Lincoln issued a proclamation admitting the state 60 days later on June 20, 1863. Meanwhile, officers for the new state were chosen, while Gov. Pierpont moved his pro-Union Virginia capital to Union-occupied Alexandria, where he asserted and exercised jurisdiction over all the remaining Virginia counties within the federal lines.[23]
+
+The question of the constitutionality of the formation of the new state was later brought before the Supreme Court of the United States in Virginia v. West Virginia. Berkeley and Jefferson counties lying on the Potomac east of the mountains, in 1863, with the consent of the reorganized government of Virginia voted in favor of annexation to West Virginia.[23]
+
+Many voters of the strongly pro-secessionist counties were absent in the Confederate Army when the vote was taken and refused to acknowledge the transfer when they returned. The Virginia General Assembly repealed the act of secession and, in 1866, brought suit against West Virginia asking the court to declare the counties a part of Virginia, which would have declared West Virginia's admission as a state unconstitutional. Meanwhile, on March 10, 1866, Congress passed a joint resolution recognizing the transfer.[23] The Supreme Court decided in favor of West Virginia in 1870.[48]
+
+During the Civil War, Union General George B. McClellan's forces gained possession of the greater part of the territory in the summer of 1861, culminating at the Battle of Rich Mountain, and Union control was never again seriously threatened. In 1863, General John D. Imboden, with 5,000 Confederates, raided a considerable portion of the state and burned Pierpont's library, although Senator Willey escaped their grasp. Bands of guerrillas burned and plundered in some sections, and were not entirely suppressed until after the war ended.[23] The Eastern Panhandle counties were more affected by the war, with military control of the area repeatedly changing hands.
+
+The area that became West Virginia actually furnished about an equal number of soldiers to the federal and Confederate armies,[49] approximately 22,000–25,000 each. In 1865, the Wheeling government found it necessary to strip voting rights from returning Confederates in order to retain control. James Ferguson, who proposed the law, said if it was not enacted he would lose election by 500 votes.[50] The property of Confederates might also be confiscated, and in 1866 a constitutional amendment disfranchising all who had given aid and comfort to the Confederacy was adopted. The addition of the Fourteenth and Fifteenth Amendments to the United States Constitution caused a reaction. The Democratic party secured control in 1870, and in 1871, the constitutional amendment of 1866 was abrogated. The first steps toward this change had been taken, however, by the Republicans in 1870. On August 22, 1872, an entirely new constitution was adopted.[23]
+
+Beginning in Reconstruction, and for several decades thereafter, the two states disputed the new state's share of the pre-war Virginia government's debts, which had mostly been incurred to finance public infrastructure improvements, such as canals, roads, and railroads under the Virginia Board of Public Works. Virginians—led by former Confederate general William Mahone—formed a political coalition based upon this: the Readjuster Party. Although West Virginia's first constitution provided for the assumption of a part of the Virginia debt, negotiations opened by Virginia in 1870 were fruitless, and in 1871, Virginia funded two-thirds of the debt and arbitrarily assigned the remainder to West Virginia.[51] The issue was finally settled in 1915, when the Supreme Court of the United States ruled that West Virginia owed Virginia $12,393,929.50.[52] The final instalment of this sum was paid in 1939.
+
+After Reconstruction, the new 35th state benefited from the development of its mineral resources more than any other single economic activity.
+
+Saltpeter caves had been employed throughout Appalachia for munitions; the border between West Virginia and Virginia includes the "Saltpeter Trail", a string of limestone caverns containing rich deposits of calcium nitrate which were rendered and sold to the government. The trail stretched from Pendleton County to the western terminus of the route in the town of Union, Monroe County. Nearly half of these caves are on the West Virginia side, including Organ Cave and Haynes Cave. In the late 18th-century, saltpeter miners in Haynes Cave found large animal bones in the deposits. These were sent by a local historian and frontier soldier Colonel John Stuart to Thomas Jefferson. The bones were named Megalonyx jeffersonii, or great-claw, and became known as Jefferson's three-toed sloth. It was declared the official state fossil of West Virginia in 2008. The West Virginia official state rock is bituminous coal,[53] and the official state gemstone is silicified Mississippian fossil Lithostrotionella coral.[54]
+
+The limestone also produced a useful quarry industry, usually small, and softer, high-calcium seams were burned to produce industrial lime. This lime was used for agricultural and construction purposes; for many years a specific portion of the C & O Railroad carried limestone rock to Clifton Forge, Virginia as an industrial flux.
+
+Salt mining had been underway since the 18th century, though it had largely played out by the time of the American Civil War, when the red salt of Kanawha County was a valued commodity of first Confederate, and later Union, forces. In years following, more sophisticated mining methods would restore West Virginia's role as a major producer of salt.
+
+However, in the second half of the 19th century, there was an even greater treasure not yet developed: bituminous coal. It would fuel much of the Industrial Revolution in the U.S. and the steamships of many of the world's navies.
+
+The residents (both Native Americans and early European settlers) had long known of the underlying coal, and that it could be used for heating and fuel.  However, for a long time, "personal" or artisanal mining was the only practical development.  After the War, with the new railroads came a practical method to transport large quantities of coal to expanding U.S. and export markets. As the anthracite mines of northwestern New Jersey and Pennsylvania began to play out during this same time period, investors and industrialists focused new interest in West Virginia. Geologists such as Dr. David T. Ansted surveyed potential coal fields and invested in land and early mining projects.
+
+The completion of the Chesapeake and Ohio Railway (C&O) across the state to the new city of Huntington on the Ohio River in 1872 opened access to the New River Coal Field. Soon, the C&O was building its huge coal pier at Newport News, Virginia on the large harbor of Hampton Roads. In 1881, the new Philadelphia-based owners of the former Atlantic, Mississippi and Ohio Railroad (AM&O), which stretched across Virginia's southern tier from Norfolk, had sights clearly set on the Mountain State, where the owners had large land holdings. Their railroad was renamed Norfolk and Western (N&W), and a new railroad city was developed at Roanoke to handle planned expansion. After its new president Frederick J. Kimball and a small party journeyed by horseback and saw firsthand the rich bituminous coal seam, which Kimball's wife named Pocahontas, the N&W redirected its planned westward expansion to reach it. Soon, the N&W was also shipping from new coal piers at Hampton Roads.
+
+In 1889, in the southern part of the state, along the Norfolk and Western rail lines, the important coal center of Bluefield, West Virginia was founded. The "capital" of the Pocahontas coalfield, this city would remain the largest city in the southern portion of the state for several decades. It shares a sister city with the same name, Bluefield, in Virginia.
+
+In the northern portion of the state and elsewhere, the older Baltimore and Ohio Railroad (B&O) and other lines also expanded to take advantage of coal opportunities. The B&O developed coal piers in Baltimore and at several points on the Great Lakes. Other significant rail carriers of coal were the Western Maryland Railway (WM), Southern Railway (SOU), and the Louisville and Nashville Railroad (L&N).
+
+Particularly notable was a latecomer, the Virginian Railway (VGN). By 1900 only the most rugged terrain of southern West Virginia was any distance from the existing railroads and mining activity. Within this area west of the New River Coalfield in Raleigh and Wyoming counties lay the Winding Gulf Coalfield, later promoted as the "Billion Dollar Coalfield".
+
+A protégé of Dr. Ansted was William Nelson Page (1854–1932), a civil engineer and mining manager in Fayette County. Former West Virginia governor William A. MacCorkle described him as a man who knew the land "as a farmer knows a field". Beginning in 1898, Page teamed with northern and European-based investors to take advantage of the undeveloped area. They acquired large tracts of land in the area, and Page began the Deepwater Railway, a short-line railroad chartered to stretch between the C&O at its line along the Kanawha River and the N&W at Matoaka—a distance of about 80 miles (130 km).
+
+Although the Deepwater plan should have provided a competitive shipping market via either railroad, leaders of the two large railroads did not appreciate the scheme. In secret collusion, each declined to negotiate favorable rates with Page, nor did they offer to purchase his railroad, as they had many other short-lines. However, if the C&O and N&W presidents thought they could thus kill the Page project, they were to be proved mistaken. One of the silent partner investors Page had enlisted was millionaire industrialist Henry Huttleston Rogers, a principal in John D. Rockefeller's Standard Oil Trust and an old hand at developing natural resources and transportation. A master at competitive "warfare", Henry Rogers did not like to lose in his endeavors and also had "deep pockets".
+
+Instead of giving up, Page (and Rogers) quietly planned and then built their tracks all the way east across Virginia, using Rogers' private fortune to finance the $40 million cost. When the renamed Virginian Railway (VGN) was completed in 1909, no fewer than three railroads were shipping ever-increasing volumes of coal to export from Hampton Roads. West Virginia coal was also under high demand at Great Lakes ports. The VGN and the N&W ultimately became parts of the modern Norfolk Southern system, and the VGN's well-engineered 21st-century tracks continue to offer a favorable gradient to Hampton Roads.
+
+As coal mining and related work became major employment activities in the state, there was considerable labor strife as working conditions, safety issues and economic concerns arose. Even in the 21st century, mining safety and ecological concerns is still challenging to the state whose coal continues to power electrical generating plants in many other states.
+
+Coal is not the only valuable mineral found in West Virginia, as the state was the site of the 1928 discovery of the 34.48 carat (6.896 g) Jones Diamond.
+
+Located in the Appalachian Mountain range, West Virginia covers an area of 24,229.76 square miles (62,754.8 km2), with 24,077.73 square miles (62,361.0 km2) of land and 152.03 square miles (393.8 km2) of water, making it the 41st-largest state in the United States.[55] West Virginia borders Pennsylvania and Maryland in the northeast, Virginia in the southeast, Ohio in the northwest, and Kentucky in the southwest. Its longest border is with Virginia at 381 miles (613 km), followed by Ohio at 243 miles (391 km), Maryland at 174 miles (280 km), Pennsylvania at 118 miles (190 km), and Kentucky at 79 miles (127 km).[56]
+
+West Virginia is located entirely within the Appalachian Region, and the state is almost entirely mountainous, giving reason to the nickname The Mountain State and the motto Montani Semper Liberi ("Mountaineers are always free"). The elevations and ruggedness drop near large rivers like the Ohio River or Shenandoah River. About 75% of the state is within the Cumberland Plateau and Allegheny Plateau regions. Though the relief is not high, the plateau region is extremely rugged in most areas. The average elevation of West Virginia is approximately 1,500 feet (460 m) above sea level, which is the highest of any U.S. state east of the Mississippi River.
+
+On the eastern state line with Virginia, high peaks in the Monongahela National Forest region give rise to an island of colder climate and ecosystems similar to those of northern New England and eastern Canada. The highest point in the state is atop Spruce Knob, at 4,863 feet (1,482 m),[57] and is covered in a boreal forest of dense spruce trees at altitudes above 4,000 feet (1,200 m). Spruce Knob lies within the Monongahela National Forest and is a part of the Spruce Knob-Seneca Rocks National Recreation Area.[58] A total of six wilderness areas can also be found within the forest. Outside the forest to the south, the New River Gorge is a canyon 1,000 feet (300 m) deep, carved by the New River. The National Park Service manages a portion of the gorge and river that has been designated as the New River Gorge National River, one of only fifteen rivers in the U.S. with this level of protection.
+
+Other areas under protection and management include:
+
+Most of West Virginia lies within the Appalachian mixed mesophytic forests ecoregion, while the higher elevations along the eastern border and in the panhandle lie within the Appalachian-Blue Ridge forests. The native vegetation for most of the state was originally mixed hardwood forest of oak, chestnut, maple, beech, and white pine, with willow and American sycamore along the state's waterways. Many of the areas are rich in biodiversity and scenic beauty, a fact appreciated by native West Virginians, who refer to their home as Almost Heaven (from the song, "Take Me Home, Country Roads" by John Denver). Before the song, it was known as "The Cog State" (Coal, Oil, and Gas) or "The Mountain State".
+
+The underlying rock strata are sandstone, shale, bituminous coal beds, and limestone laid down in a near-shore environment from sediments derived from mountains to the east, in a shallow inland sea on the west. Some beds illustrate a coastal swamp environment, some river delta, some shallow water. Sea level rose and fell many times during the Mississippian and Pennsylvanian eras, giving a variety of rock strata. The Appalachian Mountains are some of the oldest on earth, having formed more than three hundred million years ago.[59]
+
+The climate of West Virginia is generally a humid subtropical climate (Köppen climate classification Cfa, except Dfb at the higher elevations) with warm to hot, humid summers and chilly winters, increasing in severity with elevation. Some southern highland areas also have a mountain temperate climate (Köppen Cfb) where winter temperatures are more moderate and summer temperatures are somewhat cooler. However, the weather is subject in all parts of the state to change. The hardiness zones range from zone 5b in the central Appalachian mountains to zone 7a in the warmest parts of the lowest elevations.[60]
+
+In the Eastern Panhandle and the Ohio River Valley, temperatures are warm enough to see and grow subtropical plants such as southern magnolia (Magnolia grandiflora), crepe myrtle, Albizia julibrissin, American sweetgum and even the occasional needle palm and sabal minor. These plants do not thrive as well in other parts of the state. The eastern prickly pear grows well in many portions of the state.
+
+Average January temperatures range from around 26 °F (−4 °C) near the Cheat River to 41 °F (5 °C) along sections of the border with Kentucky. July averages range from 67 °F (19 °C) along the North Branch Potomac River to 76 °F (24 °C) in the western part of the state. It is cooler in the mountains than in the lower sections of the state.[61] The highest recorded temperature in the state is 112 °F (44 °C) at Martinsburg on July 10, 1936 and the lowest recorded temperature in the state is −37 °F (−38 °C) at Lewisburg on December 30, 1917.
+
+Annual precipitation ranges from less than 32 inches (810 mm) in the lower eastern section to more than 56 inches (1,400 mm) in higher parts of the Allegheny Front. Valleys in the east have lower rainfall because the Allegheny mountain ridges to the west create a partial rain shadow. Slightly more than half the rainfall occurs from April to September. Dense fogs are common in many valleys of the Kanawha section, especially the Tygart Valley. West Virginia is also one of the cloudiest states in the nation, with the cities of Elkins and Beckley ranking 9th and 10th in the U.S. respectively for the number of cloudy days per year (over 210). In addition to persistent cloudy skies caused by the damming of moisture by the Alleghenies, West Virginia also experiences some of the most frequent precipitation in the nation, with Snowshoe averaging nearly 200 days a year with either rain or snow. Snow usually lasts only a few days in the lower sections but may persist for weeks in the higher mountain areas. An average of 34 inches (860 mm) of snow falls annually in Charleston, although during the winter of 1995–1996 more than three times that amount fell as several cities in the state established new records for snowfall. Average snowfall in the Allegheny Highlands can range up to 180 inches (4,600 mm) per year. Severe weather is somewhat less prevalent in West Virginia than in most other eastern states, and it ranks among the least tornado-prone states east of the Rockies.
+
+The United States Census Bureau estimates that the population of West Virginia was 1,792,147 on July 1, 2018, a 3.28% decrease since the 2010 United States Census.[63] The center of population of West Virginia is located in Braxton County, in the town of Gassaway.[64]
+
+At the 2010 Census, the racial composition of the state's population was:
+
+In the same year, 1.2% of West Virginia's population was of Hispanic, Latino, or Spanish origin (they may be of any race).
+
+As of 2018, West Virginia has an estimated population of 1,805,832, which is a decrease of 10,025 (0.55%) from the prior year and a decrease of 47,162 (2.55%) since the previous census. This includes a natural decrease of 3,296 (108,292 births minus 111,588 deaths) and an increase from net migration of 14,209 into the state. West Virginia is the least populous southeastern state. Immigration from outside the United States resulted in a net increase of 3,691, and migration within the country produced a net increase of 10,518.
+
+Only 1.1% of the state's residents were foreign-born, placing West Virginia last among the 50 states in that statistic. It also has the lowest percentage of residents who speak a language other than English in the home (2.7%).
+
+The five largest ancestry groups in West Virginia are: German (18.9%), Irish (15.1%) American (12.9%), English (11.8%) and Italian (4.7%)[68][69] In the 2000 Census People who identified their ethnicity as simply American made up 18.7% of the population.[70]
+
+Large numbers of people of German ancestry are present in the northeastern counties of the state. People of English ancestry are present throughout the entire state. Many West Virginians who self-identify as Irish are actually Scots-Irish Protestants.
+
+2010 census data show that 16 percent of West Virginia's residents are 65 or older (exceeded only by Florida's 17 percent).[71]
+
+There were 20,928 births in 2006. Of these, 19,757 (94.40% of the births, 95.19% of the population) were to non-Hispanic whites. There were 22 births to American Indians (0.11% of the births and 0.54% of the population), 177 births to Asians (0.85% of the births and 0.68% of the population), 219 births to Hispanics (1.05% of the births and 0.88% of the population) and 753 births to blacks and others (3.60% of the births and 3.56% of the population).[73]
+
+The state's Northern Panhandle, and North-Central region feel an affinity for Pittsburgh, Pennsylvania. Also, those in the Eastern Panhandle feel a connection with the Washington, D.C. suburbs in Maryland and Virginia, and southern West Virginians often consider themselves Southerners. Finally, the towns and farms along the mid-Ohio River, which forms most of the state's western border, have an appearance and culture somewhat resembling the Midwest.[74]
+
+Note: Births in table do not add up, because Hispanics are counted both by their ethnicity and by their race, giving a higher overall number.
+
+Several surveys have been made in recent years, in 2008 by the American Religion Identity Survey,[83] in 2010 by the Pew Forum on Religion and Public Life.[84] The Pew survey results admit to a 6.5% margin of error plus or minus, while the ARIS survey says "estimates are subject to larger sampling errors in states with small populations." A characteristic of religion in Appalachian communities is the abundance of independent, non-affiliated churches, which "remain unnoted and uncounted in any census of church life in the United States". This sometimes leads to the belief that these communities are "unchurched".[85]
+
+The largest denomination as of 2010 was the United Methodist Church with 136,000 members in 1,200 congregations. The second-largest Protestant church was the American Baptist Churches USA with 88,000 members and 381 congregations. The Southern Baptist church had 44,000 members and 232 congregations. The Churches of Christ had 22,000 members and 287 congregations. The Presbyterian Church (USA) had 200 congregations and 20,000 members.[86]
+
+A survey conducted in 2015 by the Pew Research Center found that West Virginia was the seventh most "highly religious" state in the United States.[87]
+
+The economy of West Virginia nominally would be the 62nd largest economy globally behind Iraq and ahead of Croatia according to 2009 World Bank projections,[88] and the 64th largest behind Iraq and ahead of Libya according to 2009 International Monetary Fund projections.[89] The state has a projected nominal GSP of $63.34 billion in 2009 according to the Bureau of Economic Analysis report of November 2010, and a real GSP of $55.04 billion. The real GDP growth of the state in 2009 of .7% was the 7th best in the country.[90] West Virginia was one of only ten states in 2009 that grew economically.[91]
+
+While per capita income fell 2.6% nationally in 2009, West Virginia's grew at 1.8%.[92] Through the first half of 2010, exports from West Virginia topped $3 billion, growing 39.5% over the same period from the previous year and ahead of the national average by 15.7%.[92]
+
+Morgantown was ranked by Forbes as the #10 best small city in the nation to conduct business in 2010.[93] The city is also home to West Virginia University, the 95th best public university according to U.S. News & World Report in 2011.[94] The proportion of West Virginia's adult population with a bachelor's degree is the lowest in the U.S. at 17.3%.[95]
+
+The net corporate income tax rate is 6.5% while business costs are 13% below the national average.[96][97]
+
+The U.S. Bureau of Economic Analysis reported that in 2014 West Virginia's economy grew twice as fast as the next fastest growing state East of the Mississippi River, ranking third alongside Wyoming and just behind North Dakota and Texas among the fastest growing states in the United States.[98]
+
+Tourism contributed $4.27 billion to the state's economy and employed 44,400 people in 2010, making it one of the state's largest industries.[99] Many tourists, especially in the eastern mountains, are drawn to the region's notable opportunities for outdoor recreation. Canaan Valley is popular for winter sports, Seneca Rocks is one of the premier rock climbing destinations in the eastern U.S., the New River Gorge/Fayetteville area draws rock climbers as well as whitewater rafting enthusiasts, and the Monongahela National Forest is popular with hikers, backpackers, hunters, and anglers.
+
+In addition to such outdoor recreation opportunities, the state offers a number of historic and cultural attractions. Harpers Ferry National Historical Park is a historic town situated at the confluence of the Shenandoah and Potomac rivers. Harpers Ferry was the site of John Brown's 1859 raid on the U.S. Armory and Arsenal. Located at the approximate midpoint of the Appalachian Trail, Harpers Ferry is the base of the Appalachian Trail Conservancy.
+
+The Greenbrier hotel and resort, originally built in 1778, has long been considered a premier hotel, frequented by numerous world leaders and U.S. presidents over the years.
+
+West Virginia is the site of the National Radio Astronomy Observatory, which features the Green Bank Telescope. For the 1963 Centennial of the State, it hosted two high school graduate delegates from each of the 50 States at the National Youth Science Camp near Bartow, and has continued this tradition ever since. The main building of Weston State Hospital is the largest hand-cut sandstone building in the western hemisphere, second worldwide only to the Kremlin in Moscow. Tours of the building, which is a National Historic Landmark and part of the National Civil War Trail, are offered seasonally and by appointment year round. West Virginia has numerous popular festivals throughout the year.
+
+One of the major resources in West Virginia's economy is coal. According to the Energy Information Administration, West Virginia is a top coal-producer in the United States, second only to Wyoming. West Virginia is located in the heart of the Marcellus Shale Natural Gas Bed, which stretches from Tennessee north to New York in the middle of Appalachia.
+
+As of 2017, the coal industry accounted for 2% of state employment.[100]
+
+Nearly all the electricity generated in West Virginia is from coal-fired power plants. West Virginia produces a surplus of electricity and leads the Nation in net interstate electricity exports.[101] Farming is also practiced in West Virginia, but on a limited basis because of the mountainous terrain over much of the state.
+
+West Virginia has the potential to generate 4,952 GWh/year from 1,883 MW of wind power, using 80 meter high wind turbines, or 8,627 GWh/year from 2,772 MW of 100 meter wind turbines, and 60,000 GWh from 40,000 MW of photovoltaics, including 3,810 MW of rooftop photovoltaics.[102]
+
+Source:[104][105][106][107]
+
+West Virginia personal income tax is based on federal adjusted gross income (not taxable income), as modified by specific items in West Virginia law. Citizens are taxed within five income brackets, which range from 3.0% to 6.5%. The state's consumer sales tax is levied at 6% on most products except for non-prepared foods.[108]
+
+West Virginia counties administer and collect property taxes, although property tax rates reflect levies for state government, county governments, county boards of education and municipalities. Counties may also impose a hotel occupancy tax on lodging places not located within the city limits of any municipality that levies such a tax. Municipalities may levy license and gross receipts taxes on businesses located within the city limits and a hotel occupancy tax on lodging places in the city. Although the Department of Tax and Revenue plays a major role in the administration of this tax, less than half of one percent of the property tax collected goes to state government.
+
+The primary beneficiaries of the property tax are county boards of education. Property taxes are paid to the sheriff of each of the state's 55 counties. Each county and municipality can impose its own rates of property taxation within the limits set by the West Virginia Constitution. The West Virginia legislature sets the rate of tax of county boards of education. This rate is used by all county boards of education statewide. However, the total tax rate for county boards of education may differ from county to county because of excess levies. The Department of Tax and Revenue supervises and otherwise assists counties and municipalities in their work of assessment and tax rate determination. The total tax rate is a combination of the tax levies from four state taxing authorities: state, county, schools and municipal. This total tax rate varies for each of the four classes of property, which consists of personal, real and intangible properties. Property is assessed according to its use, location and value as of July 1. WV Assessments has a free searchable database of West Virginia real estate tax assessments, covering current and past years. All property is reappraised every three years; annual adjustments are made to assessments for property with a change of value. West Virginia does not impose an inheritance tax. Because of the phase-out of the federal estate tax credit, West Virginia's estate tax is not imposed on estates of persons who died on or after January 1, 2005.[109]
+
+The largest private employers in West Virginia, as of March 2011, were:[110]
+
+West Virginia governor Tomblin's proposed 2014–15 budget submitted in January 2014 had an estimated budget gap of $146–$265 million, and halfway through the 2013–14 fiscal year, tax revenues were $82 million short.[111] The West Virginia Legislature in March 2014 passed its budget bill, taking $147 million from the Rainy Day Fund to balance the 2015 budget.[112] Governor Tomblin's deputy chief of staff Jason Pizatella, after the state legislature passed the budget, said West Virginia is expecting another dismal budget in 2016 and could need $150–170 million to balance the next year's budget.[113]
+
+West Virginia coal exports declined 40% in 2013—a loss of $2.9 billion and overall total exports declined 26%.[114] West Virginia ranked last in the Gallup Economic Index for the fourth year running. West Virginia's score was −44, or a full 17 points lower than the average of −27 for the other states in the bottom ten.[115] West Virginia ranked 48th in the CNBC "Top States for Business 2013" based on measures of competitiveness such as economy, workforce and cost of living—ranking among the bottom five states for the last six years running.[116] West Virginia ranked 49th in the 2014 State New Economy Index, and has ranked in the bottom three states since 1999. West Virginia ranked last or next-to-last in critical indicators such as Workforce Education, Entrepreneurial Activity, High-Tech Jobs, and Scientists and Engineers.[117]
+
+On January 9, 2014, a chemical spill contaminated the water supply of 300,000 people in nine West Virginia counties near Charleston. According to Bloomberg News, lost wages, revenue, and other economic harm from the chemical spill could top $500 million.[118][needs update] and West Virginia's Marshall University Center for Business and Economic Research estimated that about $61 million was lost by businesses in the first four days alone after the spill.[119]
+
+In 2012, West Virginia's Gross Domestic Product (GDP) grew by 3.3%.[120] The state issued a report highlighting the state's GDP as indicating a fast-growing economy, but did not address employment indicators.[121] In 2009–2013, the U.S. real GDP increased 9.6% and total employment increased 3.9%. In West Virginia during the same time period, its real GDP increased about 11%, while total employment decreased by 1,000 jobs from 746,000 to 745,000.
+
+In 2013, West Virginia ranked last in the nation with an employment-to-population ratio of only 50%, compared to the national average of 59%.[122] The state lost 5,600 jobs in its labor force in four critical economic sectors: construction (1,900), manufacturing (1,100), retail (1,800), and education (800), while gaining just 400 in mining and logging.[123] The state's Civilian Labor Force dropped by 15,100.[124]
+
+Personal income growth in West Virginia during 2013 was only 1.5%—the lowest in the nation—and about half the national average (2.6%).[125] Overall income growth in West Virginia in the last thirty years has been only 13%—about a third the national average (37%). Wages of the impoverished bottom 1% income earners decreased by 3%, compared to the national average, which increased 19%.[126]
+
+West Virginia's poverty rate is one of the highest in the nation. 2017 estimates indicate that 19% of the state's population lives in poverty, exceeding the national average of 13%.[127]
+
+The West Virginia teachers' strike in 2018 inspired teachers in other states to take similar action.[128]
+
+United Van Lines 37th Annual Migration Study showed in 2013 that 60% more people moved out of the Mountain State than moved in.[129] West Virginia's population is expected to decline by more than 19,000 residents by 2030, and West Virginia could lose one of its three seats in the United States House of Representatives.[130] West Virginia is the only state where death rates exceeds birth rates. During 2010–2013, about 21,000 babies per year were born in West Virginia, but over these three years West Virginia had 3,000 more deaths than births.[131]
+
+Gallup-Healthways annual "State of American Well-Being" rankings reports that 1,261 concerned West Virginians rated themselves as "suffering" in categories such as Quality of Life, Physical Health, and Access to Basic Needs. Overall, West Virginia citizens rated themselves as being more miserable than people in all other states—for five years running.[132] In addition, the Gallup Well-Being Index for 2013 ranked Charleston, the state capital, and Huntington last and next-to-last out of 189 U.S. Metropolitan Statistical Areas.[133]
+
+The Annie E. Casey Foundation's National Index of Children's Progress ranked West Virginia 43rd in the nation for all kids, and last for white kids.[134] The Annie E. Casey Foundation's 2013 KIDS COUNT Data Book also ranked West Virginia's education system 47th in the nation for the second straight year.[135] Charleston, West Virginia has the worst divorce rate among 100 cities in the nation. Stephen Smith, the executive director of the West Virginia Healthy Kids and Families Coalition, said poor employment prospects are to blame: "The pressure to make a good living puts strain on a marriage, and right now it is infinitely harder to make a living here than it was 40 years ago."[136]
+
+United Health Foundation's "America's Health Rankings" for 2013 found that Americans are making considerable progress in key health measures. West Virginia, however, ranked either last or second-to-last in twenty categories, including cancer, child immunization, diabetes, disabilities, drug deaths, teeth loss, low birth weight, missed work days due to health, prescription drug overdose, preventable hospitalizations, and senior clinical care.[137] Wisconsin Population Health Institute annual "Health Rankings" for 2012 showed West Virginia spends $9,671 per capita on health care annually. El Salvador spends just $467, yet both have the same life expectancy.[138] In 2012, according to the Census Bureau, West Virginia was the only state where death rates exceeds birth rates. During 2010–2013, about 21,000 babies per year were born in West Virginia, but there were 24,000 deaths.[131] In demographics, this is called a "net mortality society".[139]
+
+The National Center for Health Statistics says national birth rates for teenagers are at historic lows—during 2007–2010, teen birth rates fell 17% nationally;. West Virginia, however, ranked last with a 3% increase in birth rates for teenagers.[140] A study by West Virginia's Marshall University showed that 19% of babies born in the state have evidence of drug or alcohol exposure.[141] This is several times the national rate, where studies show that about 5.9% of pregnant women in the U.S. use illicit drugs, and about 8.5% consume any alcohol.[142] An Institute for Health Policy Research study determined that mortality rates in Appalachia are correlated with coal production. In twenty West Virginia coal counties mining more than a million tons of coal per year and having a total population of 850,000, there are about 10,100 deaths per year, with 1,400 of those statistically attributed to deaths from heart, respiratory and kidney disease from living in an Appalachian coal county.[143]
+
+In 2015, McDowell County had the highest rate of drug-induced deaths of any county in the United States, with a rate of 141 deaths per 100,000 people. Four of the five counties with the highest rates of drug-induced deaths are in West Virginia (McDowell, Wyoming, Cabell and Raleigh Counties).[144]
+
+in Charleston
+
+The West Virginia Legislature is bicameral. It consists of the House of Delegates and the Senate, both housed in the West Virginia State Capitol. It is a citizen's legislature, meaning that legislative office is not a full-time occupation, but rather a part-time position. Consequently, the legislators often hold a full-time job in their community of residence.
+
+Typically, the legislature is in session for 60 days between January and early April. The final day of the regular session ends in a bewildering fury of last-minute legislation to meet a constitutionally imposed midnight deadline. During the remainder of the year, monthly interim sessions are held in preparation for the regular session. Legislators also gather periodically for 'special' sessions when called by the governor.
+
+The title of Lieutenant Governor is assigned by statute to the senate president.
+
+The governor, elected every four years on the same day as the U.S. presidential election, is sworn in during the following January.
+
+Governors of West Virginia can serve two consecutive terms but must sit out a term before serving a third term in office.
+
+The title of Lieutenant Governor is assigned by statute to the senate president.
+
+West Virginia is one of nineteen states that do not have a death penalty, and it is the only state in the southeastern United States to have abolished it.
+
+For the purpose of courts of general jurisdiction, the state is divided into 31 judicial circuits. Each circuit is made up of one or more counties. Circuit judges are elected in non-partisan elections to serve eight-year terms.
+
+West Virginia's highest court is the Supreme Court of Appeals. The Supreme Court of Appeals of West Virginia is the busiest appellate court of its type in the United States. West Virginia is one of 11 states with a single appellate court. The state constitution allows for the creation of an intermediate court of appeals, but the Legislature has never created one. The Supreme Court is made up of five justices, elected in non-partisan elections to 12-year terms.
+
+West Virginia is an alcoholic beverage control state. However, unlike most such states, it does not operate retail outlets, having exited that business in 1990. It retains a monopoly on wholesaling of distilled spirits only.
+
+At the state level, West Virginia's politics were largely dominated by the Democratic Party from the Great Depression through the 2000s. This was a legacy of West Virginia's very strong tradition of union membership.[145] After the 2014 midterm elections Democrats controlled the governorship, the majority of statewide offices, and one U.S. Senate seat, while Republicans held one U.S. Senate seat, all three of the state's U.S. House seats, and a majority in both houses of the West Virginia Legislature. In the 2016 elections, the Republicans held on to their seats and made gains in the State Senate and gained three statewide offices.[146][147]
+
+Since 2000, West Virginians have supported the Republican candidate in every presidential election. The state is regarded as a "deep red" state at the federal level.[145][148] In 2012 Republican Mitt Romney won the state, defeating Democrat Barack Obama with 62% of the vote to 35% for Obama. In the 2016 presidential election, Republican Donald Trump won the state with 67.86% of the popular vote, with West Virginia being the second-highest percentage voting for Trump of any state.[149]
+
+Evangelical Christians comprised 52% of the state's voters in 2008.[150] A poll in 2005 showed that 53% of West Virginia voters are anti-abortion, the seventh highest in the country.[151] A 2014 poll by Pew Research found that 35% of West Virginians supported legal abortion in "all or most cases" while 58% wanted it to be banned "in all or most cases".[152] A September 2011 Public Policy Polling survey found that 19% of West Virginia voters thought same-sex marriage should be legal, while 71% thought it should be illegal and 10% were not sure. A separate question on the same survey found that 43% of West Virginia voters supported the legal recognition of same-sex couples, with 17% supporting same-sex marriage, 26% supporting civil unions but not marriage, 54% favoring no legal recognition and 3% not sure.[153] In 2008, 58% favored troop withdrawal from Iraq while just 32% wanted troops to remain.[154] On fiscal policy in 2008, 52% said raising taxes on the wealthier individuals would benefit the economy, while 45% disagreed.[155]
+
+The West Virginia Department of Commerce is a government agency responsible for overseeing West Virginia's economy, workforce, natural resources, and tourism, the department oversees nine subsidiary agencies.[156]
+
+Highways form the backbone of transportation systems in West Virginia, with over 37,300 miles (60,000 km) of public roads in the state.[157] Airports, railroads, and rivers complete the commercial transportation modes for West Virginia. Commercial air travel is facilitated by airports in Charleston, Huntington, Morgantown, Beckley, Lewisburg, Clarksburg, and Parkersburg. All but Charleston and Huntington are subsidized by the federal Department of Transportation's Essential Air Service program. The cities of Charleston, Huntington, Beckley, Wheeling, Morgantown, Clarksburg, Parkersburg and Fairmont have bus-based public transit systems.
+
+West Virginia University in Morgantown boasts the PRT (personal rapid transit) system, the state's only single-rail public transit system. Developed by Boeing, the WVU School of Engineering and the Department of Transportation, it was a model for low-capacity light transport designed for smaller cities. Recreational transportation opportunities abound in West Virginia, including hiking trails,[158] rail trails,[159] ATV off-road trails,[160] white water rafting rivers,[161] and two tourist railroads, the Cass Scenic Railroad[162] and the Potomac Eagle Scenic Railroad.[163]
+
+West Virginia is crossed by seven Interstate Highways. I-64 enters the state near White Sulphur Springs in the mountainous east, and exits for Kentucky in the west, near Huntington. I-77 enters from Virginia in the south, near Bluefield. It runs north past Parkersburg before it crosses into Ohio. I-64 and I-77 between Charleston and Beckley are merged as toll road known as the West Virginia Turnpike, which continues as I-77 alone from Beckley to Princeton. It was constructed beginning in 1952 as a two lane road, but rebuilt beginning in 1974 to Interstate standards. Today almost nothing of the original construction remains. I-68's western terminus is in Morgantown. From there it runs east into Maryland. At the I-68 terminus in Morgantown, it meets I-79, which enters from Pennsylvania and runs through the state to its southern terminus in Charleston. I-70 briefly runs through West Virginia, crossing the northern panhandle through Wheeling, while I-470 is a bypass of Wheeling (making Wheeling among the smallest cities with an interstate bypass). I-81 also briefly runs in West Virginia through the Eastern Panhandle where it goes through Martinsburg.
+
+The interstates are supplemented by roads constructed under the Appalachian Corridor system. Four Corridors are complete. Corridor D, carrying US 50, runs from the Ohio River, and I-77, at Parkersburg to I-79 at Clarksburg. Corridor G, carrying US 119, runs from Charleston to the Kentucky border at Williamson. Corridor L, carrying US 19, runs from the Turnpike at Beckley to I-79 near Sutton (and provides a short cut of about 40 miles (64 km) and bypasses Charleston's urban traffic for traveler heading to and from Florida). Corridor Q, carrying US 460, runs through Mercer County, entering the state from Giles County, Virginia and then reentering Virginia at Tazewell County.
+
+Work continues on the long delayed Corridor H, which will carry US 48 from Weston to the Virginia line near Wardensville. As of 2018, a section from Weston to Kerens just past Elkins, and another section from Wardensville to Davis are complete. Other projects under development are a four-lane upgrade of US 35 from Scott Depot to the Ohio River at Point Pleasant, which is about two-thirds complete; a four lane upgrade of WV 10 from Logan to Man and then of WV 80 from Man to Gilbert, which is about half completed; and four lane upgrades to US 52 from Bluefield to Williamson, known as the "King Coal Highway" and from Williamson to Huntington, known as the "Tolsia Highway" which are many years from completion. A project known as the "Coalfields Expressway" is also ongoing, and will carry US 121 from Beckley west across Raleigh, Wyoming, and McDowell counties, entering Virginia near Bishop.
+
+Rail lines in the state used to be more prevalent, but many lines have been discontinued because of increased automobile traffic. Many old tracks have been converted to rail trails for recreational use, although the coal producing areas still have railroads running at near capacity. Amtrak's Cardinal roughly parallels I-64's path through the state. MARC trains serve commuters in the eastern panhandle. In 2006 Norfolk Southern along with the West Virginia and U.S. Government approved a plan to modify many of the rail tunnels in West Virginia, especially in the southern half of the state, to allow for double stacked cars (see inter-modal freight). This is expected to also help bring economic growth to the southern half of the state. An Intermodal Freight Facility is located at Prichard, just south of Huntington.
+
+Because of the mountainous nature of the entire state, West Virginia has several notable tunnels and bridges. The most famous of these is the New River Gorge Bridge, which was at a time the longest steel single-arch bridge in the world with a 3,031-foot (924 m) span. The bridge is also pictured on the West Virginia state quarter. The Fort Steuben Bridge (Weirton-Steubenville Bridge) was at the time of its construction one of only three cable-stayed steel girder trusses in the United States. "The Veterans Memorial Bridge was designed to handle traffic from the Fort Steuben Bridge as well as its own traffic load", to quote the Weirton Daily Times newspaper.[164] The 80-year-old Fort Steuben Bridge (Weirton-Steubenville Bridge) was permanently closed on January 8, 2009. The Wheeling Suspension Bridge was the first bridge built across the Ohio River in 1849 and for a time was the longest suspension bridge in the world. It is still the oldest vehicular suspension bridge in the United States still in use.
+
+Originally, the state capital was in Wheeling (1863 to 1870). It was then moved to Charleston, a more central city (1870 to 1875). However it was returned to Wheeling in 1875, until the capitol burned down in 1885. It was moved back to Charleston in 1885, and it has been there since.[165]
+
+Morgantown
+
+Wheeling
+
+Beckley
+
+Fairmont
+
+Martinsburg
+
+West Virginia is home to college sports teams from two schools—West Virginia and Marshall—that play in NCAA Division I. West Virginia is also home to several professional minor league baseball, football, soccer, and other sports teams.
+
+West Virginia's folk heritage is a part of the Appalachian folk music tradition, and includes styles of fiddling, ballad singing, and other styles that draw on Scots-Irish music. Camp Washington-Carver, a Mountain Cultural Arts Center located at Clifftop in Fayette County, hosts an annual Appalachian String Band Festival.[169] The Capitol Complex in Charleston hosts The Vandalia Gathering, where traditional Appalachian musicians compete in contests and play in impromptu jam sessions and evening concerts over the weekend.[170] The Augusta Heritage Center sponsored by Davis & Elkins College in Elkins in Randolph County produces the annual Augusta Heritage Festival, which includes intensive week-long workshops in the summer that help preserve Appalachian heritage and traditions.[171]
+
+The West Virginia Symphony Orchestra was founded in 1939, as the Charleston Civic Orchestra, before becoming the Charleston Symphony Orchestra in 1943. The first conductor was William R. Wiant, followed by the conductor Antonio Modarelli, who was written about in the November 7, 1949 Time Magazine for his composition of the River Saga, a six-section program piece about the Kanawha River according to the Charleston Gazette's November 6, 1999 photo essay, "Snapshots of the 20th Century".[172] Before coming to Charleston, Modarelli had conducted the Wheeling Symphony Orchestra and the Philadelphia Orchestra, according to the orchestra's website.[173]
+
+The Pulitzer Prize-winning 20th-century composer George Crumb was born in Charleston and earned his bachelor's degree there before moving outside the state. There had also been a series of operatic style concerts performed in Wheeling during mid-century as well.
+
+The West Virginia Cultural Center in Charleston[174] is home to the West Virginia Division of Culture and History,[175] which helps underwrite and coordinate a large number of musical activities. The center is also home to Mountain Stage, an internationally broadcast live-performance music radio program established in 1983 which is carried by many affiliates of National Public Radio.[176] The program also travels to other venues in the state such as the West Virginia University Creative Arts Center in Morgantown.[177]
+
+The center hosts concerts sponsored by the Friends of Old Time Music and Dance, which brings an assortment of acoustic roots music to West Virginians.[178] The center also hosts the West Virginia Dance Festival, which features classical and modern dance.[179]
+
+Huntington's historic Keith-Albee Theatre, built by brothers A.B. and S.J. Hyman, was originally opened to the public on May 7, 1928, and hosts a variety of performing arts and music attractions. The theatre was eventually gifted to Marshall University and is currently going through renovation to restore it to its original splendor.
+
+Every summer Elkins hosts the Augusta Heritage Festival, which brings folk musicians from around the world.[180] The town of Glenville has long been home to the annual West Virginia State Folk Festival.[181]
+
+The Mountaineer Opera House in Milton hosts a variety of musical acts.
+
+John Denver's hit song "Take Me Home, Country Roads" describes the experience of driving through West Virginia. The song mentions the Shenandoah River and the Blue Ridge Mountains, both features traversing the easternmost extremity of the state's "eastern panhandle", in Jefferson County. On March 8, 2014, West Virginia governor Earl Ray Tomblin signed House Concurrent Resolution 40 naming "Take Me Home, Country Roads" the fourth official state song of West Virginia.
+
+Symphony Sunday is an annual event hosted by the West Virginia Symphony Orchestra held in June. It is a day full day of music by community groups, food, and family fun, culminating in a free performance by the West Virginia Symphony Orchestra with a fireworks display following. The event began in 1982 and is held on the front lawn of the University of Charleston.
+
+The Daily Mail Kanawha County Majorette and Band Festival is West Virginia's longest running music festival. It is for the eight public high schools in Kanawha County. The festival began in 1947. It is held at the University of Charleston Stadium at Laidley Field in downtown Charleston.
+
+Former state parks: Booker T. Washington · Grandview · Grave Creek Mound · Mingo Oak · Mont Chateau · Morgan Morgan Monument
+
+Coordinates: 39°00′N 80°30′W / 39°N 80.5°W / 39; -80.5

en/6008.html.txt

@@ -0,0 +1,201 @@
+
+
+
+
+See text
+
+A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism.[1] Viruses infect all types of life forms, from animals and plants to microorganisms, including bacteria and archaea.[2]
+Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants, and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898,[3] more than 6,000  virus species have been described in detail,[4] of the millions of types of viruses in the environment.[5] Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity.[6][7] The study of viruses is known as virology, a subspeciality of microbiology.
+
+When infected, a host cell is forced to rapidly produce thousands of identical copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent particles, or virions, consisting of: (i) the genetic material, i.e. long molecules of DNA or RNA that encode the structure of the proteins by which the virus acts; (ii) a protein coat, the capsid, which surrounds and protects the genetic material; and in some cases (iii) an outside envelope of lipids. The shapes of these virus particles range from simple helical and icosahedral forms to more complex structures. Most virus species have virions too small to be seen with an optical microscope as they are one hundredth the size of most bacteria.
+
+The origins of viruses in the evolutionary history of life are unclear: some may have evolved from plasmids—pieces of DNA that can move between cells—while others may have evolved from bacteria. In evolution, viruses are an important means of horizontal gene transfer, which increases genetic diversity in a way analogous to sexual reproduction.[8] Viruses are considered by some biologists to be a life form, because they carry genetic material, reproduce, and evolve through natural selection, although they lack the key characteristics such as cell structure that are generally considered necessary criteria for life. Because they possess some but not all such qualities, viruses have been described as "organisms at the edge of life",[9] and as self-replicators.[10]
+
+Viruses spread in many ways. One transmission pathway is through disease-bearing organisms known as vectors: for example, viruses are often transmitted from plant to plant by insects that feed on plant sap, such as aphids; and viruses in animals can be carried by blood-sucking insects. Influenza viruses are spread by coughing and sneezing. Norovirus and rotavirus, common causes of viral gastroenteritis, are transmitted by the faecal–oral route, passed by hand-to-mouth contact or in food or water. The infectious dose of norovirus required to produce infection in humans is less than 100 particles.[11] HIV is one of several viruses transmitted through sexual contact and by exposure to infected blood. The variety of host cells that a virus can infect is called its "host range". This can be narrow, meaning a virus is capable of infecting few species, or broad, meaning it is capable of infecting many.[12]
+
+Viral infections in animals provoke an immune response that usually eliminates the infecting virus. Immune responses can also be produced by vaccines, which confer an artificially acquired immunity to the specific viral infection. Some viruses, including those that cause AIDS, HPV infection, and viral hepatitis, evade these immune responses and result in chronic infections. Several antiviral drugs have been developed.
+
+The word is from the Latin neuter vīrus referring to poison and other noxious liquids, from the same Indo-European base as Sanskrit viṣa, Avestan vīša, and ancient Greek ἰός (all meaning "poison"), first attested in English in 1398 in John Trevisa's translation of Bartholomeus Anglicus's De Proprietatibus Rerum.[13][14] Virulent, from Latin virulentus (poisonous), dates to c. 1400.[15][16] A meaning of "agent that causes infectious disease" is first recorded in 1728,[14] long before the discovery of viruses by Dmitri Ivanovsky in 1892. The English plural is viruses (sometimes also  vira)[17]  whereas the Latin word is a mass noun, which has no classically attested plural (vīra is used in Neo-Latin[18]). The adjective viral dates to 1948.[19] The term virion (plural virions), which dates from 1959,[20] is also used to refer to a single viral particle that is released from the cell and is capable of infecting other cells of the same type.[21]
+
+Louis Pasteur was unable to find a causative agent for rabies and speculated about a pathogen too small to be detected by microscopes.[22] In 1884, the French microbiologist Charles Chamberland invented the Chamberland filter (or Pasteur-Chamberland filter) with pores small enough to remove all bacteria from a solution passed through it.[23] In 1892, the Russian biologist Dmitri Ivanovsky used this filter to study what is now known as the tobacco mosaic virus: crushed leaf extracts from infected tobacco plants remained infectious even after filtration to remove bacteria. Ivanovsky suggested the infection might be caused by a toxin produced by bacteria, but did not pursue the idea.[24] At the time it was thought that all infectious agents could be retained by filters and grown on a nutrient medium—this was part of the germ theory of disease.[3] In 1898, the Dutch microbiologist Martinus Beijerinck repeated the experiments and became convinced that the filtered solution contained a new form of infectious agent.[25] He observed that the agent multiplied only in cells that were dividing, but as his experiments did not show that it was made of particles, he called it a contagium vivum fluidum (soluble living germ) and re-introduced the word virus. Beijerinck maintained that viruses were liquid in nature, a theory later discredited by Wendell Stanley, who proved they were particulate.[24] In the same year Friedrich Loeffler and Paul Frosch passed the first animal virus through a similar filter: aphthovirus, the agent of foot-and-mouth disease.[26]
+
+In the early 20th century, the English bacteriologist Frederick Twort discovered a group of viruses that infect bacteria, now called bacteriophages[27] (or commonly 'phages'), and the French-Canadian microbiologist Félix d'Herelle described viruses that, when added to bacteria on an agar plate, would produce areas of dead bacteria. He accurately diluted a suspension of these viruses and discovered that the highest dilutions (lowest virus concentrations), rather than killing all the bacteria, formed discrete areas of dead organisms. Counting these areas and multiplying by the dilution factor allowed him to calculate the number of viruses in the original suspension.[28] Phages were heralded as a potential treatment for diseases such as typhoid and cholera, but their promise was forgotten with the development of penicillin. The development of bacterial resistance to antibiotics has renewed interest in the therapeutic use of bacteriophages.[29]
+
+By the end of the 19th century, viruses were defined in terms of their infectivity, their ability to pass filters, and their requirement for living hosts. Viruses had been grown only in plants and animals. In 1906, Ross Granville Harrison invented a method for growing tissue in lymph, and, in 1913, E. Steinhardt, C. Israeli, and R. A. Lambert used this method to grow vaccinia virus in fragments of guinea pig corneal tissue.[30] In 1928, H. B. Maitland and M. C. Maitland grew vaccinia virus in suspensions of minced hens' kidneys. Their method was not widely adopted until the 1950s when poliovirus was grown on a large scale for vaccine production.[31]
+
+Another breakthrough came in 1931, when the American pathologist Ernest William Goodpasture and Alice Miles Woodruff grew influenza and several other viruses in fertilised chicken eggs.[32] In 1949, John Franklin Enders, Thomas Weller, and Frederick Robbins grew poliovirus in cultured cells from aborted human embryonic tissue,[33] the first virus to be grown without using solid animal tissue or eggs. This work enabled Hilary Koprowski, and then Jonas Salk, to make an effective polio vaccine.[34]
+
+The first images of viruses were obtained upon the invention of electron microscopy in 1931 by the German engineers Ernst Ruska and Max Knoll.[35] In 1935, American biochemist and virologist Wendell Meredith Stanley examined the tobacco mosaic virus and found it was mostly made of protein.[36] A short time later, this virus was separated into protein and RNA parts.[37]
+The tobacco mosaic virus was the first to be crystallised and its structure could, therefore, be elucidated in detail. The first X-ray diffraction pictures of the crystallised virus were obtained by Bernal and Fankuchen in 1941. On the basis of her X-ray crystallographic pictures, Rosalind Franklin discovered the full structure of the virus in 1955.[38] In the same year, Heinz Fraenkel-Conrat and Robley Williams showed that purified tobacco mosaic virus RNA and its protein coat can assemble by themselves to form functional viruses, suggesting that this simple mechanism was probably the means through which viruses were created within their host cells.[39]
+
+The second half of the 20th century was the golden age of virus discovery and most of the documented species of animal, plant, and bacterial viruses were discovered during these years.[40] In 1957, equine arterivirus and the cause of Bovine virus diarrhoea (a pestivirus) were discovered. In 1963, the hepatitis B virus was discovered by Baruch Blumberg,[41] and in 1965, Howard Temin described the first retrovirus. Reverse transcriptase, the enzyme that retroviruses use to make DNA copies of their RNA, was first described in 1970, independently by Temin and David Baltimore.[42] In 1983 Luc Montagnier's team at the Pasteur Institute in France, first isolated the retrovirus now called HIV.[43] In 1989 Michael Houghton's team at Chiron Corporation discovered Hepatitis C.[44][45]
+
+Viruses are found wherever there is life and have probably existed since living cells first evolved.[46] The origin of viruses is unclear because they do not form fossils, so molecular techniques are used to investigate how they arose.[47] In addition, viral genetic material occasionally integrates into the germline of the host organisms, by which they can be passed on vertically to the offspring of the host for many generations. This provides an invaluable source of information for paleovirologists to trace back ancient viruses that have existed up to millions of years ago. There are three main hypotheses that aim to explain the origins of viruses:[48][49]
+
+In the past, there were problems with all of these hypotheses: the regressive hypothesis did not explain why even the smallest of cellular parasites do not resemble viruses in any way. The escape hypothesis did not explain the complex capsids and other structures on virus particles. The virus-first hypothesis contravened the definition of viruses in that they require host cells.[52] Viruses are now recognised as ancient and as having origins that pre-date the divergence of life into the three domains.[63] This discovery has led modern virologists to reconsider and re-evaluate these three classical hypotheses.[63]
+
+The evidence for an ancestral world of RNA cells[64] and computer analysis of viral and host DNA sequences are giving a better understanding of the evolutionary relationships between different viruses and may help identify the ancestors of modern viruses. To date, such analyses have not proved which of these hypotheses is correct.[64] It seems unlikely that all currently known viruses have a common ancestor, and viruses have probably arisen numerous times in the past by one or more mechanisms.[65]
+
+Scientific opinions differ on whether viruses are a form of life, or organic structures that interact with living organisms.[10] They have been described as "organisms at the edge of life",[9] since they resemble organisms in that they possess genes, evolve by natural selection,[66] and reproduce by creating multiple copies of themselves through self-assembly. Although they have genes, they do not have a cellular structure, which is often seen as the basic unit of life. Viruses do not have their own metabolism, and require a host cell to make new products. They therefore cannot naturally reproduce outside a host cell[67]—although bacterial species such as rickettsia and chlamydia are considered living organisms despite the same limitation.[68][69] Accepted forms of life use cell division to reproduce, whereas viruses spontaneously assemble within cells. They differ from autonomous growth of crystals as they inherit genetic mutations while being subject to natural selection. Virus self-assembly within host cells has implications for the study of the origin of life, as it lends further credence to the hypothesis that life could have started as self-assembling organic molecules.[2]
+
+Viruses display a wide diversity of shapes and sizes, called 'morphologies'. In general, viruses are much smaller than bacteria. Most viruses that have been studied have a diameter between 20 and 300 nanometres. Some filoviruses have a total length of up to 1400 nm; their diameters are only about 80 nm.[70] Most viruses cannot be seen with an optical microscope, so scanning and transmission electron microscopes are used to visualise them.[71] To increase the contrast between viruses and the background, electron-dense "stains" are used. These are solutions of salts of heavy metals, such as tungsten, that scatter the electrons from regions covered with the stain. When virions are coated with stain (positive staining), fine detail is obscured. Negative staining overcomes this problem by staining the background only.[72]
+
+A complete virus particle, known as a virion, consists of nucleic acid surrounded by a protective coat of protein called a capsid. These are formed from identical protein subunits called capsomeres.[73] Viruses can have a lipid "envelope" derived from the host cell membrane. The capsid is made from proteins encoded by the viral genome and its shape serves as the basis for morphological distinction.[74][75] Virally-coded protein subunits will self-assemble to form a capsid, in general requiring the presence of the virus genome. Complex viruses code for proteins that assist in the construction of their capsid. Proteins associated with nucleic acid are known as nucleoproteins, and the association of viral capsid proteins with viral nucleic acid is called a nucleocapsid. The capsid and entire virus structure can be mechanically (physically) probed through atomic force microscopy.[76][77] In general, there are four main morphological virus types:
+
+The poxviruses are large, complex viruses that have an unusual morphology. The viral genome is associated with proteins within a central disc structure known as a nucleoid. The nucleoid is surrounded by a membrane and two lateral bodies of unknown function. The virus has an outer envelope with a thick layer of protein studded over its surface. The whole virion is slightly pleomorphic, ranging from ovoid to brick-shaped.[84]
+
+Mimivirus is one of the largest characterised viruses, with a capsid diameter of 400 nm. Protein filaments measuring 100 nm project from the surface. The capsid appears hexagonal under an electron microscope, therefore the capsid is probably icosahedral.[85] In 2011, researchers discovered the largest then known virus in samples of water collected from the ocean floor off the coast of Las Cruces, Chile. Provisionally named Megavirus chilensis, it can be seen with a basic optical microscope.[86] In 2013, the Pandoravirus genus was discovered in Chile and Australia, and has genomes about twice as large as Megavirus and Mimivirus.[87] All giant viruses have dsDNA genomes and they are classified into several families: Mimiviridae, Pithoviridae, Pandoraviridae, Phycodnaviridae, and the Mollivirus genus.[88]
+
+Some viruses that infect Archaea have complex structures unrelated to any other form of virus, with a wide variety of unusual shapes, ranging from spindle-shaped structures to viruses that resemble hooked rods, teardrops or even bottles. Other archaeal viruses resemble the tailed bacteriophages, and can have multiple tail structures.[89]
+
+An enormous variety of genomic structures can be seen among viral species; as a group, they contain more structural genomic diversity than plants, animals, archaea, or bacteria. There are millions of different types of viruses,[5] although fewer than 7,000 types have been described in detail.[90] As of September 2015, the NCBI Virus genome database has more than 75,000 complete genome sequences,[91] but there are doubtlessly many more to be discovered.[92][93]
+
+A virus has either a DNA or an RNA genome and is called a DNA virus or an RNA virus, respectively. The vast majority of viruses have RNA genomes. Plant viruses tend to have single-stranded RNA genomes and bacteriophages tend to have double-stranded DNA genomes.[94]
+
+Viral genomes are circular, as in the polyomaviruses, or linear, as in the adenoviruses. The type of nucleic acid is irrelevant to the shape of the genome. Among RNA viruses and certain DNA viruses, the genome is often divided up into separate parts, in which case it is called segmented. For RNA viruses, each segment often codes for only one protein and they are usually found together in one capsid. All segments are not required to be in the same virion for the virus to be infectious, as demonstrated by brome mosaic virus and several other plant viruses.[70]
+
+A viral genome, irrespective of nucleic acid type, is almost always either single-stranded or double-stranded. Single-stranded genomes consist of an unpaired nucleic acid, analogous to one-half of a ladder split down the middle. Double-stranded genomes consist of two complementary paired nucleic acids, analogous to a ladder. The virus particles of some virus families, such as those belonging to the Hepadnaviridae, contain a genome that is partially double-stranded and partially single-stranded.[94]
+
+For most viruses with RNA genomes and some with single-stranded DNA genomes, the single strands are said to be either positive-sense (called the 'plus-strand') or negative-sense (called the 'minus-strand'), depending on if they are complementary to the viral messenger RNA (mRNA). Positive-sense viral RNA is in the same sense as viral mRNA and thus at least a part of it can be immediately translated by the host cell. Negative-sense viral RNA is complementary to mRNA and thus must be converted to positive-sense RNA by an RNA-dependent RNA polymerase before translation. DNA nomenclature for viruses with single-sense genomic ssDNA is similar to RNA nomenclature, in that positive-strand viral ssDNA is identical in sequence to the viral mRNA and is thus a coding strand, while negative-strand viral ssDNA is complementary to the viral mRNA and is thus a template strand.[94] Several types of ssDNA and ssRNA viruses have genomes that are ambisense in that transcription can occur off both strands in a double-stranded replicative intermediate. Examples include geminiviruses, which are ssDNA plant viruses and arenaviruses, which are ssRNA viruses of animals.[95]
+
+Genome size varies greatly between species. The smallest—the ssDNA circoviruses, family Circoviridae—code for only two proteins and have a genome size of only two kilobases;[96] the largest—the pandoraviruses—have genome sizes of around two megabases which code for about 2500 proteins.[97] Virus genes rarely have introns and often are arranged in the genome so that they overlap.[98]
+
+In general, RNA viruses have smaller genome sizes than DNA viruses because of a higher error-rate when replicating, and have a maximum upper size limit.[47] Beyond this, errors when replicating render the virus useless or uncompetitive. To compensate, RNA viruses often have segmented genomes—the genome is split into smaller molecules—thus reducing the chance that an error in a single-component genome will incapacitate the entire genome. In contrast, DNA viruses generally have larger genomes because of the high fidelity of their replication enzymes.[99] Single-strand DNA viruses are an exception to this rule, as mutation rates for these genomes can approach the extreme of the ssRNA virus case.[100]
+
+Viruses undergo genetic change by several mechanisms. These include a process called antigenic drift where individual bases in the DNA or RNA mutate to other bases. Most of these point mutations are "silent"—they do not change the protein that the gene encodes—but others can confer evolutionary advantages such as resistance to antiviral drugs.[101][102] Antigenic shift occurs when there is a major change in the genome of the virus. This can be a result of recombination or reassortment. When this happens with influenza viruses, pandemics might result.[103] RNA viruses often exist as quasispecies or swarms of viruses of the same species but with slightly different genome nucleoside sequences. Such quasispecies are a prime target for natural selection.[104]
+
+Segmented genomes confer evolutionary advantages; different strains of a virus with a segmented genome can shuffle and combine genes and produce progeny viruses (or offspring) that have unique characteristics. This is called reassortment or 'viral sex'.[105]
+
+Genetic recombination is the process by which a strand of DNA is broken and then joined to the end of a different DNA molecule. This can occur when viruses infect cells simultaneously and studies of viral evolution have shown that recombination has been rampant in the species studied.[106] Recombination is common to both RNA and DNA viruses.[107][108]
+
+Viral populations do not grow through cell division, because they are acellular. Instead, they use the machinery and metabolism of a host cell to produce multiple copies of themselves, and they assemble in the cell.[109] When infected, the host cell is forced to rapidly produce thousands of identical copies of the original virus.[110]
+
+Their life cycle differs greatly between species, but there are six basic stages in their life cycle:[111]
+
+Attachment is a specific binding between viral capsid proteins and specific receptors on the host cellular surface. This specificity determines the host range and type of host cell of a virus. For example, HIV infects a limited range of human leucocytes. This is because its surface protein, gp120, specifically interacts with the CD4 molecule—a chemokine receptor—which is most commonly found on the surface of CD4+ T-Cells. This mechanism has evolved to favour those viruses that infect only cells in which they are capable of replication. Attachment to the receptor can induce the viral envelope protein to undergo changes that result in the fusion of viral and cellular membranes, or changes of non-enveloped virus surface proteins that allow the virus to enter.[112]
+
+Penetration follows attachment: Virions enter the host cell through receptor-mediated endocytosis or membrane fusion in a process often known as viral entry. The infection of plant and fungal cells is different from that of animal cells. Plants have a rigid cell wall made of cellulose, and fungi one of chitin, so most viruses can get inside these cells only after trauma to the cell wall.[113] Nearly all plant viruses (such as tobacco mosaic virus) can also move directly from cell to cell, in the form of single-stranded nucleoprotein complexes, through pores called plasmodesmata.[114] Bacteria, like plants, have strong cell walls that a virus must breach to infect the cell. Given that bacterial cell walls are much thinner than plant cell walls due to their much smaller size, some viruses have evolved mechanisms that inject their genome into the bacterial cell across the cell wall, while the viral capsid remains outside.[115]
+
+Uncoating is a process in which the viral capsid is removed: This may be by degradation by viral enzymes or host enzymes or by simple dissociation; the end-result is the releasing of the viral genomic nucleic acid.[116]
+
+Replication of viruses involves primarily multiplication of the genome. Replication involves synthesis of viral messenger RNA (mRNA) from "early" genes (with exceptions for positive sense RNA viruses), viral protein synthesis, possible assembly of viral proteins, then viral genome replication mediated by early or regulatory protein expression. This may be followed, for complex viruses with larger genomes, by one or more further rounds of mRNA synthesis: "late" gene expression is, in general, of structural or virion proteins.[117]
+
+Assembly – Following the structure-mediated self-assembly of the virus particles, some modification of the proteins often occurs. In viruses such as HIV, this modification (sometimes called maturation) occurs after the virus has been released from the host cell.[118]
+
+Release – Viruses can be released from the host cell by lysis, a process that kills the cell by bursting its membrane and cell wall if present: this is a feature of many bacterial and some animal viruses. Some viruses undergo a lysogenic cycle where the viral genome is incorporated by genetic recombination into a specific place in the host's chromosome. The viral genome is then known as a "provirus" or, in the case of bacteriophages a "prophage".[119] Whenever the host divides, the viral genome is also replicated. The viral genome is mostly silent within the host. At some point, the provirus or prophage may give rise to active virus, which may lyse the host cells.[120] Enveloped viruses (e.g., HIV) typically are released from the host cell by budding. During this process the virus acquires its envelope, which is a modified piece of the host's plasma or other, internal membrane.[121]
+
+The genetic material within virus particles, and the method by which the material is replicated, varies considerably between different types of viruses.
+
+The range of structural and biochemical effects that viruses have on the host cell is extensive.[126] These are called 'cytopathic effects'.[127] Most virus infections eventually result in the death of the host cell. The causes of death include cell lysis, alterations to the cell's surface membrane and apoptosis.[128] Often cell death is caused by cessation of its normal activities because of suppression by virus-specific proteins, not all of which are components of the virus particle.[129] The distinction between cytopathic and harmless is gradual. Some viruses, such as Epstein–Barr virus, can cause cells to proliferate without causing malignancy,[130] while others, such as papillomaviruses, are established causes of cancer.[131]
+
+Some viruses cause no apparent changes to the infected cell. Cells in which the virus is latent and inactive show few signs of infection and often function normally.[132] This causes persistent infections and the virus is often dormant for many months or years. This is often the case with herpes viruses.[133][134]
+
+Viruses are by far the most abundant biological entities on Earth and they outnumber all the others put together.[135] They infect all types of cellular life including animals, plants, bacteria and fungi.[90] Different types of viruses can infect only a limited range of hosts and many are species-specific. Some, such as smallpox virus for example, can infect only one species—in this case humans,[136] and are said to have a narrow host range. Other viruses, such as rabies virus, can infect different species of mammals and are said to have a broad range.[137] The viruses that infect plants are harmless to animals, and most viruses that infect other animals are harmless to humans.[138] The host range of some bacteriophages is limited to a single strain of bacteria and they can be used to trace the source of outbreaks of infections by a method called phage typing.[139] The complete set of viruses in an organism or habitat is called the virome; for example, all human viruses constitute the human virome.[140]
+
+Classification seeks to describe the diversity of viruses by naming and grouping them on the basis of similarities. In 1962, André Lwoff, Robert Horne, and Paul Tournier were the first to develop a means of virus classification, based on the Linnaean hierarchical system.[141] This system based classification on phylum, class, order, family, genus, and species. Viruses were grouped according to their shared properties (not those of their hosts) and the type of nucleic acid forming their genomes.[142] In 1966, the International Committee on Taxonomy of Viruses (ICTV) was formed. The system proposed by Lwoff, Horne and Tournier was initially not accepted by the ICTV because the small genome size of viruses and their high rate of mutation made it difficult to determine their ancestry beyond order. As such, the Baltimore classification system has come to be used to supplement the more traditional hierarchy.[143] Starting in 2018, the ICTV began to acknowledge deeper evolutionary relationships between viruses that have been discovered over time and adopted a 15-rank classification system ranging from realm to species.[144]
+
+The ICTV developed the current classification system and wrote guidelines that put a greater weight on certain virus properties to maintain family uniformity. A unified taxonomy (a universal system for classifying viruses) has been established. Only a small part of the total diversity of viruses has been studied.[145] As of 2019, 4 realms, 9 kingdoms, 16 phyla, 2 subphyla, 36 classes, 55 orders, 8 suborders, 168 families, 103 subfamilies, 1,421 genera, 68 subgenera, and 6,589 species of viruses have been defined by the ICTV.[4]
+
+The general taxonomic structure of taxon ranges and the suffixes used in taxonomic names are shown hereafter. As of 2019, the ranks of subrealm, subkingdom, and subclass are unused, whereas all other ranks are in use.
+
+The Nobel Prize-winning biologist David Baltimore devised the Baltimore classification system.[42][146] The ICTV classification system is used in conjunction with the Baltimore classification system in modern virus classification.[147][148][149]
+
+The Baltimore classification of viruses is based on the mechanism of mRNA production. Viruses must generate mRNAs from their genomes to produce proteins and replicate themselves, but different mechanisms are used to achieve this in each virus family. Viral genomes may be single-stranded (ss) or double-stranded (ds), RNA or DNA, and may or may not use reverse transcriptase (RT). In addition, ssRNA viruses may be either sense (+) or antisense (−). This classification places viruses into seven groups:
+
+
+
+Examples of common human diseases caused by viruses include the common cold, influenza, chickenpox, and cold sores. Many serious diseases such as rabies, Ebola virus disease, AIDS (HIV), avian influenza, and SARS are caused by viruses. The relative ability of viruses to cause disease is described in terms of virulence. Other diseases are under investigation to discover if they have a virus as the causative agent, such as the possible connection between human herpesvirus 6 (HHV6) and neurological diseases such as multiple sclerosis and chronic fatigue syndrome.[151] There is controversy over whether the bornavirus, previously thought to cause neurological diseases in horses, could be responsible for psychiatric illnesses in humans.[152]
+
+Viruses have different mechanisms by which they produce disease in an organism, which depends largely on the viral species. Mechanisms at the cellular level primarily include cell lysis, the breaking open and subsequent death of the cell. In multicellular organisms, if enough cells die, the whole organism will start to suffer the effects. Although viruses cause disruption of healthy homeostasis, resulting in disease, they may exist relatively harmlessly within an organism. An example would include the ability of the herpes simplex virus, which causes cold sores, to remain in a dormant state within the human body. This is called latency[153] and is a characteristic of the herpes viruses, including Epstein–Barr virus, which causes glandular fever, and varicella zoster virus, which causes chickenpox and shingles. Most people have been infected with at least one of these types of herpes virus.[154] These latent viruses might sometimes be beneficial, as the presence of the virus can increase immunity against bacterial pathogens, such as Yersinia pestis.[155]
+
+Some viruses can cause lifelong or chronic infections, where the viruses continue to replicate in the body despite the host's defence mechanisms.[156] This is common in hepatitis B virus and hepatitis C virus infections. People chronically infected are known as carriers, as they serve as reservoirs of infectious virus.[157] In populations with a high proportion of carriers, the disease is said to be endemic.[158]
+
+Viral epidemiology is the branch of medical science that deals with the transmission and control of virus infections in humans. Transmission of viruses can be vertical, which means from mother to child, or horizontal, which means from person to person. Examples of vertical transmission include hepatitis B virus and HIV, where the baby is born already infected with the virus.[159] Another, more rare, example is the varicella zoster virus, which, although causing relatively mild infections in children and adults, can be fatal to the foetus and newborn baby.[160]
+
+Horizontal transmission is the most common mechanism of spread of viruses in populations.[161] Horizontal transmission can occur when body fluids are exchanged during sexual activity, by exchange of saliva or when contaminated food or water is ingested. It can also occur when aerosols containing viruses are inhaled or by insect vectors such as when infected mosquitoes penetrate the skin of a host.[161] Most types of viruses are restricted to just one or two of these mechanisms and they are referred to as "respiratory viruses" or "enteric viruses" and so forth. The rate or speed of transmission of viral infections depends on factors that include population density, the number of susceptible individuals, (i.e., those not immune),[162] the quality of healthcare and the weather.[163]
+
+Epidemiology is used to break the chain of infection in populations during outbreaks of viral diseases.[164] Control measures are used that are based on knowledge of how the virus is transmitted. It is important to find the source, or sources, of the outbreak and to identify the virus. Once the virus has been identified, the chain of transmission can sometimes be broken by vaccines. When vaccines are not available, sanitation and disinfection can be effective. Often, infected people are isolated from the rest of the community, and those that have been exposed to the virus are placed in quarantine.[165] To control the outbreak of foot-and-mouth disease in cattle in Britain in 2001, thousands of cattle were slaughtered.[166] Most viral infections of humans and other animals have incubation periods during which the infection causes no signs or symptoms.[167] Incubation periods for viral diseases range from a few days to weeks, but are known for most infections.[168] Somewhat overlapping, but mainly following the incubation period, there is a period of communicability—a time when an infected individual or animal is contagious and can infect another person or animal.[168] This, too, is known for many viral infections, and knowledge of the length of both periods is important in the control of outbreaks.[169] When outbreaks cause an unusually high proportion of cases in a population, community, or region, they are called epidemics. If outbreaks spread worldwide, they are called pandemics.[170]
+
+A pandemic is a worldwide epidemic. The 1918 flu pandemic, which lasted until 1919, was a category 5 influenza pandemic caused by an unusually severe and deadly influenza A virus. The victims were often healthy young adults, in contrast to most influenza outbreaks, which predominantly affect juvenile, elderly, or otherwise-weakened patients.[171] Older estimates say it killed 40–50 million people,[172] while more recent research suggests that it may have killed as many as 100 million people, or 5% of the world's population in 1918.[173]
+
+Although viral pandemics are rare events, HIV—which evolved from viruses found in monkeys and chimpanzees—has been pandemic since at least the 1980s.[174] During the 20th century there were four pandemics caused by influenza virus and those that occurred in 1918, 1957 and 1968 were severe.[175] Most researchers believe that HIV originated in sub-Saharan Africa during the 20th century;[176] it is now a pandemic, with an estimated 37.9 million people now living with the disease worldwide.[177][177] There were about 770,000 deaths from AIDS in 2018.[178] The Joint United Nations Programme on HIV/AIDS (UNAIDS) and the World Health Organization (WHO) estimate that AIDS has killed more than 25 million people since it was first recognised on 5 June 1981, making it one of the most destructive epidemics in recorded history.[179] In 2007 there were 2.7 million new HIV infections and 2 million HIV-related deaths.[180]
+
+Several highly lethal viral pathogens are members of the Filoviridae. Filoviruses are filament-like viruses that cause viral hemorrhagic fever, and include ebolaviruses and marburgviruses. Marburg virus, first discovered in 1967, attracted widespread press attention in April 2005 for an outbreak in Angola.[181] Ebola virus disease has also caused intermittent outbreaks with high mortality rates since 1976 when it was first identified. The worst and most recent one is the 2013–2016 West Africa epidemic.[182]
+
+With the exception of smallpox, most pandemics are caused by newly evolved viruses. These "emergent" viruses are usually mutants of less harmful viruses that have circulated previously either in humans or other animals.[183]
+
+Severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS)  are caused by new types of coronaviruses. Other coronaviruses are known to cause mild infections in humans,[184] so the virulence and rapid spread of SARS infections—that by July 2003 had caused around 8,000 cases and 800 deaths—was unexpected and most countries were not prepared.[185]
+
+A related coronavirus emerged in Wuhan, China in November 2019 and spread rapidly around the world. Thought to have originated in bats and subsequently named severe acute respiratory syndrome coronavirus 2, infections with the virus caused a pandemic in 2020.[186][187][188] Unprecedented restrictions in peacetime have been placed on international travel,[189] and curfews imposed in several major cities worldwide.[190]
+
+Viruses are an established cause of cancer in humans and other species. Viral cancers occur only in a minority of infected persons (or animals). Cancer viruses come from a range of virus families, including both RNA and DNA viruses, and so there is no single type of "oncovirus" (an obsolete term originally used for acutely transforming retroviruses). The development of cancer is determined by a variety of factors such as host immunity[191] and mutations in the host.[192] Viruses accepted to cause human cancers include some genotypes of human papillomavirus, hepatitis B virus, hepatitis C virus, Epstein–Barr virus, Kaposi's sarcoma-associated herpesvirus and human T-lymphotropic virus. The most recently discovered human cancer virus is a polyomavirus (Merkel cell polyomavirus) that causes most cases of a rare form of skin cancer called Merkel cell carcinoma.[193]
+Hepatitis viruses can develop into a chronic viral infection that leads to liver cancer.[194][195] Infection by human T-lymphotropic virus can lead to tropical spastic paraparesis and adult T-cell leukaemia.[196] Human papillomaviruses are an established cause of cancers of cervix, skin, anus, and penis.[197] Within the Herpesviridae, Kaposi's sarcoma-associated herpesvirus causes Kaposi's sarcoma and body-cavity lymphoma, and Epstein–Barr virus causes Burkitt's lymphoma, Hodgkin's lymphoma, B lymphoproliferative disorder, and nasopharyngeal carcinoma.[198] Merkel cell polyomavirus closely related to SV40 and mouse polyomaviruses that have been used as animal models for cancer viruses for over 50 years.[199]
+
+The body's first line of defence against viruses is the innate immune system. This comprises cells and other mechanisms that defend the host from infection in a non-specific manner. This means that the cells of the innate system recognise, and respond to, pathogens in a generic way, but, unlike the adaptive immune system, it does not confer long-lasting or protective immunity to the host.[200]
+
+RNA interference is an important innate defence against viruses.[201] Many viruses have a replication strategy that involves double-stranded RNA (dsRNA). When such a virus infects a cell, it releases its RNA molecule or molecules, which immediately bind to a protein complex called a dicer that cuts the RNA into smaller pieces. A biochemical pathway—the RISC complex—is activated, which ensures cell survival by degrading the viral mRNA. Rotaviruses have evolved to avoid this defence mechanism by not uncoating fully inside the cell, and releasing newly produced mRNA through pores in the particle's inner capsid. Their genomic dsRNA remains protected inside the core of the virion.[202][203]
+
+When the adaptive immune system of a vertebrate encounters a virus, it produces specific antibodies that bind to the virus and often render it non-infectious. This is called humoral immunity. Two types of antibodies are important. The first, called IgM, is highly effective at neutralising viruses but is produced by the cells of the immune system only for a few weeks. The second, called IgG, is produced indefinitely. The presence of IgM in the blood of the host is used to test for acute infection, whereas IgG indicates an infection sometime in the past.[204] IgG antibody is measured when tests for immunity are carried out.[205]
+
+Antibodies can continue to be an effective defence mechanism even after viruses have managed to gain entry to the host cell. A protein that is in cells, called TRIM21, can attach to the antibodies on the surface of the virus particle. This primes the subsequent destruction of the virus by the enzymes of the cell's proteosome system.[206]
+
+A second defence of vertebrates against viruses is called cell-mediated immunity and involves immune cells known as T cells. The body's cells constantly display short fragments of their proteins on the cell's surface, and, if a T cell recognises a suspicious viral fragment there, the host cell is destroyed by 'killer T' cells and the virus-specific T-cells proliferate. Cells such as the macrophage are specialists at this antigen presentation.[207] The production of interferon is an important host defence mechanism. This is a hormone produced by the body when viruses are present. Its role in immunity is complex; it eventually stops the viruses from reproducing by killing the infected cell and its close neighbours.[208]
+
+Not all virus infections produce a protective immune response in this way. HIV evades the immune system by constantly changing the amino acid sequence of the proteins on the surface of the virion. This is known as "escape mutation" as the viral epitopes escape recognition by the host immune response. These persistent viruses evade immune control by sequestration, blockade of antigen presentation, cytokine resistance, evasion of natural killer cell activities, escape from apoptosis, and antigenic shift.[209] Other viruses, called 'neurotropic viruses', are disseminated by neural spread where the immune system may be unable to reach them.
+
+Because viruses use vital metabolic pathways within host cells to replicate, they are difficult to eliminate without using drugs that cause toxic effects to host cells in general. The most effective medical approaches to viral diseases are vaccinations to provide immunity to infection, and antiviral drugs that selectively interfere with viral replication.
+
+Vaccination is a cheap and effective way of preventing infections by viruses. Vaccines were used to prevent viral infections long before the discovery of the actual viruses. Their use has resulted in a dramatic decline in morbidity (illness) and mortality (death) associated with viral infections such as polio, measles, mumps and rubella.[210] Smallpox infections have been eradicated.[211] Vaccines are available to prevent over thirteen viral infections of humans,[212] and more are used to prevent viral infections of animals.[213] Vaccines can consist of live-attenuated or killed viruses, or viral proteins (antigens).[214] Live vaccines contain weakened forms of the virus, which do not cause the disease but, nonetheless, confer immunity. Such viruses are called attenuated. Live vaccines can be dangerous when given to people with a weak immunity (who are described as immunocompromised), because in these people, the weakened virus can cause the original disease.[215] Biotechnology and genetic engineering techniques are used to produce subunit vaccines. These vaccines use only the capsid proteins of the virus. Hepatitis B vaccine is an example of this type of vaccine.[216] Subunit vaccines are safe for immunocompromised patients because they cannot cause the disease.[217] The yellow fever virus vaccine, a live-attenuated strain called 17D, is probably the safest and most effective vaccine ever generated.[218]
+
+Antiviral drugs are often nucleoside analogues (fake DNA building-blocks), which viruses mistakenly incorporate into their genomes during replication. The life-cycle of the virus is then halted because the newly synthesised DNA is inactive. This is because these analogues lack the hydroxyl groups, which, along with phosphorus atoms, link together to form the strong "backbone" of the DNA molecule. This is called DNA chain termination.[219] Examples of nucleoside analogues are aciclovir for Herpes simplex virus infections and lamivudine for HIV and hepatitis B virus infections. Aciclovir is one of the oldest and most frequently prescribed antiviral drugs.[220]
+Other antiviral drugs in use target different stages of the viral life cycle. HIV is dependent on a proteolytic enzyme called the HIV-1 protease for it to become fully infectious. There is a large class of drugs called protease inhibitors that inactivate this enzyme.[221]
+
+Hepatitis C is caused by an RNA virus. In 80% of people infected, the disease is chronic, and without treatment, they are infected for the remainder of their lives. There is now an effective treatment that uses the nucleoside analogue drug ribavirin combined with interferon.[222] The treatment of chronic carriers of the hepatitis B virus by using a similar strategy using lamivudine has been developed.[223]
+
+Viruses infect all cellular life and, although viruses occur universally, each cellular species has its own specific range that often infect only that species.[224] Some viruses, called satellites, can replicate only within cells that have already been infected by another virus.[60]
+
+Viruses are important pathogens of livestock. Diseases such as foot-and-mouth disease and bluetongue are caused by viruses.[225] Companion animals such as cats, dogs, and horses, if not vaccinated, are susceptible to serious viral infections. Canine parvovirus is caused by a small DNA virus and infections are often fatal in pups.[226] Like all invertebrates, the honey bee is susceptible to many viral infections.[227] Most viruses co-exist harmlessly in their host and cause no signs or symptoms of disease.[3]
+
+There are many types of plant virus, but often they cause only a loss of yield, and it is not economically viable to try to control them. Plant viruses are often spread from plant to plant by organisms, known as vectors. These are usually insects, but some fungi, nematode worms, and single-celled organisms have been shown to be vectors. When control of plant virus infections is considered economical, for perennial fruits, for example, efforts are concentrated on killing the vectors and removing alternate hosts such as weeds.[228] Plant viruses cannot infect humans and other animals because they can reproduce only in living plant cells.[229]
+
+Originally from Peru, the potato has become a staple crop worldwide.[230] The potato virus Y causes disease in potatoes and related species including tomatoes and peppers. In the 1980s, this virus acquired economical importance when it proved difficult to control in seed potato crops. Transmitted by aphids, this virus can reduce crop yields by up to 80 per cent, causing significant losses to potato yields.[231]
+
+Plants have elaborate and effective defence mechanisms against viruses. One of the most effective is the presence of so-called resistance (R) genes. Each R gene confers resistance to a particular virus by triggering localised areas of cell death around the infected cell, which can often be seen with the unaided eye as large spots. This stops the infection from spreading.[232] RNA interference is also an effective defence in plants.[233] When they are infected, plants often produce natural disinfectants that kill viruses, such as salicylic acid, nitric oxide, and reactive oxygen molecules.[234]
+
+Plant virus particles or virus-like particles (VLPs) have applications in both biotechnology and nanotechnology. The capsids of most plant viruses are simple and robust structures and can be produced in large quantities either by the infection of plants or by expression in a variety of heterologous systems. Plant virus particles can be modified genetically and chemically to encapsulate foreign material and can be incorporated into supramolecular structures for use in biotechnology.[235]
+
+Bacteriophages are a common and diverse group of viruses and are the most abundant biological entity in aquatic environments—there are up to ten times more of these viruses in the oceans than there are bacteria,[236] reaching levels of 250,000,000 bacteriophages per millilitre of seawater.[237] These viruses infect specific bacteria by binding to surface receptor molecules and then entering the cell. Within a short amount of time, in some cases just minutes, bacterial polymerase starts translating viral mRNA into protein. These proteins go on to become either new virions within the cell, helper proteins, which help assembly of new virions, or proteins involved in cell lysis. Viral enzymes aid in the breakdown of the cell membrane, and, in the case of the T4 phage, in just over twenty minutes after injection over three hundred phages could be released.[238]
+
+The major way bacteria defend themselves from bacteriophages is by producing enzymes that destroy foreign DNA. These enzymes, called restriction endonucleases, cut up the viral DNA that bacteriophages inject into bacterial cells.[239] Bacteria also contain a system that uses CRISPR sequences to retain fragments of the genomes of viruses that the bacteria have come into contact with in the past, which allows them to block the virus's replication through a form of RNA interference.[240][241] This genetic system provides bacteria with acquired immunity to infection.[242]
+
+Some viruses replicate within archaea: these are double-stranded DNA viruses with unusual and sometimes unique shapes.[6][89] These viruses have been studied in most detail in the thermophilic archaea, particularly the orders Sulfolobales and Thermoproteales.[243] Defences against these viruses involve RNA interference from repetitive DNA sequences within archaean genomes that are related to the genes of the viruses.[244][245] Most archaea have CRISPR–Cas systems as an adaptive defence against viruses. These enable archaea to retain sections of viral DNA, which are then used to target and eliminate subsequent infections by the virus using a process similar to RNA interference.[246]
+
+Viruses are the most abundant biological entity in aquatic environments[2] There are about ten million of them in a teaspoon of seawater.[247] Most of these viruses are bacteriophages infecting heterotrophic bacteria and cyanophages infecting cyanobacteria and they are essential to the regulation of saltwater and freshwater ecosystems.[248]
+Bacteriophages are harmless to plants and animals, and are essential to the regulation of marine and freshwater ecosystems[249]  are  important mortality agents of phytoplankton, the base of the foodchain in aquatic environments.[250] They infect and destroy bacteria in aquatic microbial communities, and are one of the most important mechanisms of recycling carbon and nutrient cycling in marine environments. The organic molecules released from the dead bacterial cells stimulate fresh bacterial and algal growth, in a process known as the viral shunt.[251] In particular, lysis of bacteria by viruses has been shown to enhance nitrogen cycling and stimulate phytoplankton growth.[252]  Viral activity may also affect the biological pump, the process whereby carbon is sequestered in the deep ocean.[253]
+
+Microorganisms constitute more than 90% of the biomass in the sea. It is estimated that viruses kill approximately 20% of this biomass each day and that there are 10 to 15 times as many viruses in the oceans as there are bacteria and archaea.[254] Viruses are also major agents responsible for the destruction of phytoplankton including harmful algal blooms,[255]
+The number of viruses in the oceans decreases further offshore and deeper into the water, where there are fewer host organisms.[253]
+
+In January 2018, scientists reported that 800 million viruses, mainly of marine origin, are deposited daily from the Earth's atmosphere onto every square meter of the planet's surface, as the result of a global atmospheric stream of viruses, circulating above the weather system but below the altitude of usual airline travel, distributing viruses around the planet.[256][257]
+
+Like any organism, marine mammals are susceptible to viral infections. In 1988 and 2002, thousands of harbour seals were killed in Europe by phocine distemper virus.[258] Many other viruses, including caliciviruses, herpesviruses, adenoviruses and parvoviruses, circulate in marine mammal populations.[253]
+
+Viruses are an important natural means of transferring genes between different species, which increases genetic diversity and drives evolution.[8] It is thought that viruses played a central role in early evolution, before the diversification of the last universal common ancestor into bacteria, archaea and eukaryotes.[259] Viruses are still one of the largest reservoirs of unexplored genetic diversity on Earth.[253]
+
+Viruses are important to the study of molecular and cell biology as they provide simple systems that can be used to manipulate and investigate the functions of cells.[260] The study and use of viruses have provided valuable information about aspects of cell biology.[261] For example, viruses have been useful in the study of genetics and helped our understanding of the basic mechanisms of molecular genetics, such as DNA replication, transcription, RNA processing, translation, protein transport, and immunology.
+
+Geneticists often use viruses as vectors to introduce genes into cells that they are studying. This is useful for making the cell produce a foreign substance, or to study the effect of introducing a new gene into the genome. In a similar fashion, virotherapy uses viruses as vectors to treat various diseases, as they can specifically target cells and DNA. It shows promising use in the treatment of cancer and in gene therapy. Eastern European scientists have used phage therapy as an alternative to antibiotics for some time, and interest in this approach is increasing, because of the high level of antibiotic resistance now found in some pathogenic bacteria.[262]
+The expression of heterologous proteins by viruses is the basis of several manufacturing processes that are currently being used for the production of various proteins such as vaccine antigens and antibodies. Industrial processes have been recently developed using viral vectors and a number of pharmaceutical proteins are currently in pre-clinical and clinical trials.[263]
+
+Virotherapy involves the use of genetically modified viruses to treat diseases.[264] Viruses have been modified by scientists to reproduce in cancer cells and destroy them but not infect healthy cells. Talimogene laherparepvec (T-VEC), for example, is a modified herpes simplex virus that has had a gene, which is required for viruses to replicate in healthy cells, deleted and replaced with a human gene (GM-CSF) that stimulates immunity. When this virus infects cancer cells, it destroys them and in doing so the presence the GM-CSF gene attracts dendritic cells from the surrounding tissues of the body. The dendritic cells process the dead cancer cells and present components of them to other cells of the immune system.[265] Having completed successful clinical trials, the virus gained approval for the treatment of melanoma in late 2015.[266] Viruses that have been reprogrammed to kill cancer cells are called oncolytic viruses.[267]
+
+Current trends in nanotechnology promise to make much more versatile use of viruses. From the viewpoint of a materials scientist, viruses can be regarded as organic nanoparticles.
+Their surface carries specific tools that enable them to cross the barriers of their host cells. The size and shape of viruses and the number and nature of the functional groups on their surface is precisely defined. As such, viruses are commonly used in materials science as scaffolds for covalently linked surface modifications. A particular quality of viruses is that they can be tailored by directed evolution. The powerful techniques developed by life sciences are becoming the basis of engineering approaches towards nanomaterials, opening a wide range of applications far beyond biology and medicine.[268]
+
+Because of their size, shape, and well-defined chemical structures, viruses have been used as templates for organising materials on the nanoscale. Recent examples include work at the Naval Research Laboratory in Washington, D.C., using Cowpea mosaic virus (CPMV) particles to amplify signals in DNA microarray based sensors. In this application, the virus particles separate the fluorescent dyes used for signalling to prevent the formation of non-fluorescent dimers that act as quenchers.[269] Another example is the use of CPMV as a nanoscale breadboard for molecular electronics.[270]
+
+Many viruses can be synthesised de novo ("from scratch") and the first synthetic virus was created in 2002.[271] Although somewhat of a misconception, it is not the actual virus that is synthesised, but rather its DNA genome (in case of a DNA virus), or a cDNA copy of its genome (in case of RNA viruses). For many virus families the naked synthetic DNA or RNA (once enzymatically converted back from the synthetic cDNA) is infectious when introduced into a cell. That is, they contain all the necessary information to produce new viruses. This technology is now being used to investigate novel vaccine strategies.[272] The ability to synthesise viruses has far-reaching consequences, since viruses can no longer be regarded as extinct, as long as the information of their genome sequence is known and permissive cells are available. As of November 2017[update], the full-length genome sequences of 7454 different viruses, including smallpox, are publicly available in an online database maintained by the National Institutes of Health.[273]
+
+The ability of viruses to cause devastating epidemics in human societies has led to the concern that viruses could be weaponised for biological warfare. Further concern was raised by the successful recreation of the infamous 1918 influenza virus in a laboratory.[274]
+Smallpox virus devastated numerous societies throughout history before its eradication. There are only two centres in the world authorised by the WHO to keep stocks of smallpox virus: the State Research Center of Virology and Biotechnology VECTOR in Russia and the Centers for Disease Control and Prevention in the United States.[275] It may be used as a weapon,[275] as the vaccine for smallpox sometimes had severe side-effects, it is no longer used routinely in any country. Thus, much of the modern human population has almost no established resistance to smallpox and would be vulnerable to the virus.[275]
+

en/6009.html.txt

@@ -0,0 +1,201 @@
+
+
+
+
+See text
+
+A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism.[1] Viruses infect all types of life forms, from animals and plants to microorganisms, including bacteria and archaea.[2]
+Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants, and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898,[3] more than 6,000  virus species have been described in detail,[4] of the millions of types of viruses in the environment.[5] Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity.[6][7] The study of viruses is known as virology, a subspeciality of microbiology.
+
+When infected, a host cell is forced to rapidly produce thousands of identical copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent particles, or virions, consisting of: (i) the genetic material, i.e. long molecules of DNA or RNA that encode the structure of the proteins by which the virus acts; (ii) a protein coat, the capsid, which surrounds and protects the genetic material; and in some cases (iii) an outside envelope of lipids. The shapes of these virus particles range from simple helical and icosahedral forms to more complex structures. Most virus species have virions too small to be seen with an optical microscope as they are one hundredth the size of most bacteria.
+
+The origins of viruses in the evolutionary history of life are unclear: some may have evolved from plasmids—pieces of DNA that can move between cells—while others may have evolved from bacteria. In evolution, viruses are an important means of horizontal gene transfer, which increases genetic diversity in a way analogous to sexual reproduction.[8] Viruses are considered by some biologists to be a life form, because they carry genetic material, reproduce, and evolve through natural selection, although they lack the key characteristics such as cell structure that are generally considered necessary criteria for life. Because they possess some but not all such qualities, viruses have been described as "organisms at the edge of life",[9] and as self-replicators.[10]
+
+Viruses spread in many ways. One transmission pathway is through disease-bearing organisms known as vectors: for example, viruses are often transmitted from plant to plant by insects that feed on plant sap, such as aphids; and viruses in animals can be carried by blood-sucking insects. Influenza viruses are spread by coughing and sneezing. Norovirus and rotavirus, common causes of viral gastroenteritis, are transmitted by the faecal–oral route, passed by hand-to-mouth contact or in food or water. The infectious dose of norovirus required to produce infection in humans is less than 100 particles.[11] HIV is one of several viruses transmitted through sexual contact and by exposure to infected blood. The variety of host cells that a virus can infect is called its "host range". This can be narrow, meaning a virus is capable of infecting few species, or broad, meaning it is capable of infecting many.[12]
+
+Viral infections in animals provoke an immune response that usually eliminates the infecting virus. Immune responses can also be produced by vaccines, which confer an artificially acquired immunity to the specific viral infection. Some viruses, including those that cause AIDS, HPV infection, and viral hepatitis, evade these immune responses and result in chronic infections. Several antiviral drugs have been developed.
+
+The word is from the Latin neuter vīrus referring to poison and other noxious liquids, from the same Indo-European base as Sanskrit viṣa, Avestan vīša, and ancient Greek ἰός (all meaning "poison"), first attested in English in 1398 in John Trevisa's translation of Bartholomeus Anglicus's De Proprietatibus Rerum.[13][14] Virulent, from Latin virulentus (poisonous), dates to c. 1400.[15][16] A meaning of "agent that causes infectious disease" is first recorded in 1728,[14] long before the discovery of viruses by Dmitri Ivanovsky in 1892. The English plural is viruses (sometimes also  vira)[17]  whereas the Latin word is a mass noun, which has no classically attested plural (vīra is used in Neo-Latin[18]). The adjective viral dates to 1948.[19] The term virion (plural virions), which dates from 1959,[20] is also used to refer to a single viral particle that is released from the cell and is capable of infecting other cells of the same type.[21]
+
+Louis Pasteur was unable to find a causative agent for rabies and speculated about a pathogen too small to be detected by microscopes.[22] In 1884, the French microbiologist Charles Chamberland invented the Chamberland filter (or Pasteur-Chamberland filter) with pores small enough to remove all bacteria from a solution passed through it.[23] In 1892, the Russian biologist Dmitri Ivanovsky used this filter to study what is now known as the tobacco mosaic virus: crushed leaf extracts from infected tobacco plants remained infectious even after filtration to remove bacteria. Ivanovsky suggested the infection might be caused by a toxin produced by bacteria, but did not pursue the idea.[24] At the time it was thought that all infectious agents could be retained by filters and grown on a nutrient medium—this was part of the germ theory of disease.[3] In 1898, the Dutch microbiologist Martinus Beijerinck repeated the experiments and became convinced that the filtered solution contained a new form of infectious agent.[25] He observed that the agent multiplied only in cells that were dividing, but as his experiments did not show that it was made of particles, he called it a contagium vivum fluidum (soluble living germ) and re-introduced the word virus. Beijerinck maintained that viruses were liquid in nature, a theory later discredited by Wendell Stanley, who proved they were particulate.[24] In the same year Friedrich Loeffler and Paul Frosch passed the first animal virus through a similar filter: aphthovirus, the agent of foot-and-mouth disease.[26]
+
+In the early 20th century, the English bacteriologist Frederick Twort discovered a group of viruses that infect bacteria, now called bacteriophages[27] (or commonly 'phages'), and the French-Canadian microbiologist Félix d'Herelle described viruses that, when added to bacteria on an agar plate, would produce areas of dead bacteria. He accurately diluted a suspension of these viruses and discovered that the highest dilutions (lowest virus concentrations), rather than killing all the bacteria, formed discrete areas of dead organisms. Counting these areas and multiplying by the dilution factor allowed him to calculate the number of viruses in the original suspension.[28] Phages were heralded as a potential treatment for diseases such as typhoid and cholera, but their promise was forgotten with the development of penicillin. The development of bacterial resistance to antibiotics has renewed interest in the therapeutic use of bacteriophages.[29]
+
+By the end of the 19th century, viruses were defined in terms of their infectivity, their ability to pass filters, and their requirement for living hosts. Viruses had been grown only in plants and animals. In 1906, Ross Granville Harrison invented a method for growing tissue in lymph, and, in 1913, E. Steinhardt, C. Israeli, and R. A. Lambert used this method to grow vaccinia virus in fragments of guinea pig corneal tissue.[30] In 1928, H. B. Maitland and M. C. Maitland grew vaccinia virus in suspensions of minced hens' kidneys. Their method was not widely adopted until the 1950s when poliovirus was grown on a large scale for vaccine production.[31]
+
+Another breakthrough came in 1931, when the American pathologist Ernest William Goodpasture and Alice Miles Woodruff grew influenza and several other viruses in fertilised chicken eggs.[32] In 1949, John Franklin Enders, Thomas Weller, and Frederick Robbins grew poliovirus in cultured cells from aborted human embryonic tissue,[33] the first virus to be grown without using solid animal tissue or eggs. This work enabled Hilary Koprowski, and then Jonas Salk, to make an effective polio vaccine.[34]
+
+The first images of viruses were obtained upon the invention of electron microscopy in 1931 by the German engineers Ernst Ruska and Max Knoll.[35] In 1935, American biochemist and virologist Wendell Meredith Stanley examined the tobacco mosaic virus and found it was mostly made of protein.[36] A short time later, this virus was separated into protein and RNA parts.[37]
+The tobacco mosaic virus was the first to be crystallised and its structure could, therefore, be elucidated in detail. The first X-ray diffraction pictures of the crystallised virus were obtained by Bernal and Fankuchen in 1941. On the basis of her X-ray crystallographic pictures, Rosalind Franklin discovered the full structure of the virus in 1955.[38] In the same year, Heinz Fraenkel-Conrat and Robley Williams showed that purified tobacco mosaic virus RNA and its protein coat can assemble by themselves to form functional viruses, suggesting that this simple mechanism was probably the means through which viruses were created within their host cells.[39]
+
+The second half of the 20th century was the golden age of virus discovery and most of the documented species of animal, plant, and bacterial viruses were discovered during these years.[40] In 1957, equine arterivirus and the cause of Bovine virus diarrhoea (a pestivirus) were discovered. In 1963, the hepatitis B virus was discovered by Baruch Blumberg,[41] and in 1965, Howard Temin described the first retrovirus. Reverse transcriptase, the enzyme that retroviruses use to make DNA copies of their RNA, was first described in 1970, independently by Temin and David Baltimore.[42] In 1983 Luc Montagnier's team at the Pasteur Institute in France, first isolated the retrovirus now called HIV.[43] In 1989 Michael Houghton's team at Chiron Corporation discovered Hepatitis C.[44][45]
+
+Viruses are found wherever there is life and have probably existed since living cells first evolved.[46] The origin of viruses is unclear because they do not form fossils, so molecular techniques are used to investigate how they arose.[47] In addition, viral genetic material occasionally integrates into the germline of the host organisms, by which they can be passed on vertically to the offspring of the host for many generations. This provides an invaluable source of information for paleovirologists to trace back ancient viruses that have existed up to millions of years ago. There are three main hypotheses that aim to explain the origins of viruses:[48][49]
+
+In the past, there were problems with all of these hypotheses: the regressive hypothesis did not explain why even the smallest of cellular parasites do not resemble viruses in any way. The escape hypothesis did not explain the complex capsids and other structures on virus particles. The virus-first hypothesis contravened the definition of viruses in that they require host cells.[52] Viruses are now recognised as ancient and as having origins that pre-date the divergence of life into the three domains.[63] This discovery has led modern virologists to reconsider and re-evaluate these three classical hypotheses.[63]
+
+The evidence for an ancestral world of RNA cells[64] and computer analysis of viral and host DNA sequences are giving a better understanding of the evolutionary relationships between different viruses and may help identify the ancestors of modern viruses. To date, such analyses have not proved which of these hypotheses is correct.[64] It seems unlikely that all currently known viruses have a common ancestor, and viruses have probably arisen numerous times in the past by one or more mechanisms.[65]
+
+Scientific opinions differ on whether viruses are a form of life, or organic structures that interact with living organisms.[10] They have been described as "organisms at the edge of life",[9] since they resemble organisms in that they possess genes, evolve by natural selection,[66] and reproduce by creating multiple copies of themselves through self-assembly. Although they have genes, they do not have a cellular structure, which is often seen as the basic unit of life. Viruses do not have their own metabolism, and require a host cell to make new products. They therefore cannot naturally reproduce outside a host cell[67]—although bacterial species such as rickettsia and chlamydia are considered living organisms despite the same limitation.[68][69] Accepted forms of life use cell division to reproduce, whereas viruses spontaneously assemble within cells. They differ from autonomous growth of crystals as they inherit genetic mutations while being subject to natural selection. Virus self-assembly within host cells has implications for the study of the origin of life, as it lends further credence to the hypothesis that life could have started as self-assembling organic molecules.[2]
+
+Viruses display a wide diversity of shapes and sizes, called 'morphologies'. In general, viruses are much smaller than bacteria. Most viruses that have been studied have a diameter between 20 and 300 nanometres. Some filoviruses have a total length of up to 1400 nm; their diameters are only about 80 nm.[70] Most viruses cannot be seen with an optical microscope, so scanning and transmission electron microscopes are used to visualise them.[71] To increase the contrast between viruses and the background, electron-dense "stains" are used. These are solutions of salts of heavy metals, such as tungsten, that scatter the electrons from regions covered with the stain. When virions are coated with stain (positive staining), fine detail is obscured. Negative staining overcomes this problem by staining the background only.[72]
+
+A complete virus particle, known as a virion, consists of nucleic acid surrounded by a protective coat of protein called a capsid. These are formed from identical protein subunits called capsomeres.[73] Viruses can have a lipid "envelope" derived from the host cell membrane. The capsid is made from proteins encoded by the viral genome and its shape serves as the basis for morphological distinction.[74][75] Virally-coded protein subunits will self-assemble to form a capsid, in general requiring the presence of the virus genome. Complex viruses code for proteins that assist in the construction of their capsid. Proteins associated with nucleic acid are known as nucleoproteins, and the association of viral capsid proteins with viral nucleic acid is called a nucleocapsid. The capsid and entire virus structure can be mechanically (physically) probed through atomic force microscopy.[76][77] In general, there are four main morphological virus types:
+
+The poxviruses are large, complex viruses that have an unusual morphology. The viral genome is associated with proteins within a central disc structure known as a nucleoid. The nucleoid is surrounded by a membrane and two lateral bodies of unknown function. The virus has an outer envelope with a thick layer of protein studded over its surface. The whole virion is slightly pleomorphic, ranging from ovoid to brick-shaped.[84]
+
+Mimivirus is one of the largest characterised viruses, with a capsid diameter of 400 nm. Protein filaments measuring 100 nm project from the surface. The capsid appears hexagonal under an electron microscope, therefore the capsid is probably icosahedral.[85] In 2011, researchers discovered the largest then known virus in samples of water collected from the ocean floor off the coast of Las Cruces, Chile. Provisionally named Megavirus chilensis, it can be seen with a basic optical microscope.[86] In 2013, the Pandoravirus genus was discovered in Chile and Australia, and has genomes about twice as large as Megavirus and Mimivirus.[87] All giant viruses have dsDNA genomes and they are classified into several families: Mimiviridae, Pithoviridae, Pandoraviridae, Phycodnaviridae, and the Mollivirus genus.[88]
+
+Some viruses that infect Archaea have complex structures unrelated to any other form of virus, with a wide variety of unusual shapes, ranging from spindle-shaped structures to viruses that resemble hooked rods, teardrops or even bottles. Other archaeal viruses resemble the tailed bacteriophages, and can have multiple tail structures.[89]
+
+An enormous variety of genomic structures can be seen among viral species; as a group, they contain more structural genomic diversity than plants, animals, archaea, or bacteria. There are millions of different types of viruses,[5] although fewer than 7,000 types have been described in detail.[90] As of September 2015, the NCBI Virus genome database has more than 75,000 complete genome sequences,[91] but there are doubtlessly many more to be discovered.[92][93]
+
+A virus has either a DNA or an RNA genome and is called a DNA virus or an RNA virus, respectively. The vast majority of viruses have RNA genomes. Plant viruses tend to have single-stranded RNA genomes and bacteriophages tend to have double-stranded DNA genomes.[94]
+
+Viral genomes are circular, as in the polyomaviruses, or linear, as in the adenoviruses. The type of nucleic acid is irrelevant to the shape of the genome. Among RNA viruses and certain DNA viruses, the genome is often divided up into separate parts, in which case it is called segmented. For RNA viruses, each segment often codes for only one protein and they are usually found together in one capsid. All segments are not required to be in the same virion for the virus to be infectious, as demonstrated by brome mosaic virus and several other plant viruses.[70]
+
+A viral genome, irrespective of nucleic acid type, is almost always either single-stranded or double-stranded. Single-stranded genomes consist of an unpaired nucleic acid, analogous to one-half of a ladder split down the middle. Double-stranded genomes consist of two complementary paired nucleic acids, analogous to a ladder. The virus particles of some virus families, such as those belonging to the Hepadnaviridae, contain a genome that is partially double-stranded and partially single-stranded.[94]
+
+For most viruses with RNA genomes and some with single-stranded DNA genomes, the single strands are said to be either positive-sense (called the 'plus-strand') or negative-sense (called the 'minus-strand'), depending on if they are complementary to the viral messenger RNA (mRNA). Positive-sense viral RNA is in the same sense as viral mRNA and thus at least a part of it can be immediately translated by the host cell. Negative-sense viral RNA is complementary to mRNA and thus must be converted to positive-sense RNA by an RNA-dependent RNA polymerase before translation. DNA nomenclature for viruses with single-sense genomic ssDNA is similar to RNA nomenclature, in that positive-strand viral ssDNA is identical in sequence to the viral mRNA and is thus a coding strand, while negative-strand viral ssDNA is complementary to the viral mRNA and is thus a template strand.[94] Several types of ssDNA and ssRNA viruses have genomes that are ambisense in that transcription can occur off both strands in a double-stranded replicative intermediate. Examples include geminiviruses, which are ssDNA plant viruses and arenaviruses, which are ssRNA viruses of animals.[95]
+
+Genome size varies greatly between species. The smallest—the ssDNA circoviruses, family Circoviridae—code for only two proteins and have a genome size of only two kilobases;[96] the largest—the pandoraviruses—have genome sizes of around two megabases which code for about 2500 proteins.[97] Virus genes rarely have introns and often are arranged in the genome so that they overlap.[98]
+
+In general, RNA viruses have smaller genome sizes than DNA viruses because of a higher error-rate when replicating, and have a maximum upper size limit.[47] Beyond this, errors when replicating render the virus useless or uncompetitive. To compensate, RNA viruses often have segmented genomes—the genome is split into smaller molecules—thus reducing the chance that an error in a single-component genome will incapacitate the entire genome. In contrast, DNA viruses generally have larger genomes because of the high fidelity of their replication enzymes.[99] Single-strand DNA viruses are an exception to this rule, as mutation rates for these genomes can approach the extreme of the ssRNA virus case.[100]
+
+Viruses undergo genetic change by several mechanisms. These include a process called antigenic drift where individual bases in the DNA or RNA mutate to other bases. Most of these point mutations are "silent"—they do not change the protein that the gene encodes—but others can confer evolutionary advantages such as resistance to antiviral drugs.[101][102] Antigenic shift occurs when there is a major change in the genome of the virus. This can be a result of recombination or reassortment. When this happens with influenza viruses, pandemics might result.[103] RNA viruses often exist as quasispecies or swarms of viruses of the same species but with slightly different genome nucleoside sequences. Such quasispecies are a prime target for natural selection.[104]
+
+Segmented genomes confer evolutionary advantages; different strains of a virus with a segmented genome can shuffle and combine genes and produce progeny viruses (or offspring) that have unique characteristics. This is called reassortment or 'viral sex'.[105]
+
+Genetic recombination is the process by which a strand of DNA is broken and then joined to the end of a different DNA molecule. This can occur when viruses infect cells simultaneously and studies of viral evolution have shown that recombination has been rampant in the species studied.[106] Recombination is common to both RNA and DNA viruses.[107][108]
+
+Viral populations do not grow through cell division, because they are acellular. Instead, they use the machinery and metabolism of a host cell to produce multiple copies of themselves, and they assemble in the cell.[109] When infected, the host cell is forced to rapidly produce thousands of identical copies of the original virus.[110]
+
+Their life cycle differs greatly between species, but there are six basic stages in their life cycle:[111]
+
+Attachment is a specific binding between viral capsid proteins and specific receptors on the host cellular surface. This specificity determines the host range and type of host cell of a virus. For example, HIV infects a limited range of human leucocytes. This is because its surface protein, gp120, specifically interacts with the CD4 molecule—a chemokine receptor—which is most commonly found on the surface of CD4+ T-Cells. This mechanism has evolved to favour those viruses that infect only cells in which they are capable of replication. Attachment to the receptor can induce the viral envelope protein to undergo changes that result in the fusion of viral and cellular membranes, or changes of non-enveloped virus surface proteins that allow the virus to enter.[112]
+
+Penetration follows attachment: Virions enter the host cell through receptor-mediated endocytosis or membrane fusion in a process often known as viral entry. The infection of plant and fungal cells is different from that of animal cells. Plants have a rigid cell wall made of cellulose, and fungi one of chitin, so most viruses can get inside these cells only after trauma to the cell wall.[113] Nearly all plant viruses (such as tobacco mosaic virus) can also move directly from cell to cell, in the form of single-stranded nucleoprotein complexes, through pores called plasmodesmata.[114] Bacteria, like plants, have strong cell walls that a virus must breach to infect the cell. Given that bacterial cell walls are much thinner than plant cell walls due to their much smaller size, some viruses have evolved mechanisms that inject their genome into the bacterial cell across the cell wall, while the viral capsid remains outside.[115]
+
+Uncoating is a process in which the viral capsid is removed: This may be by degradation by viral enzymes or host enzymes or by simple dissociation; the end-result is the releasing of the viral genomic nucleic acid.[116]
+
+Replication of viruses involves primarily multiplication of the genome. Replication involves synthesis of viral messenger RNA (mRNA) from "early" genes (with exceptions for positive sense RNA viruses), viral protein synthesis, possible assembly of viral proteins, then viral genome replication mediated by early or regulatory protein expression. This may be followed, for complex viruses with larger genomes, by one or more further rounds of mRNA synthesis: "late" gene expression is, in general, of structural or virion proteins.[117]
+
+Assembly – Following the structure-mediated self-assembly of the virus particles, some modification of the proteins often occurs. In viruses such as HIV, this modification (sometimes called maturation) occurs after the virus has been released from the host cell.[118]
+
+Release – Viruses can be released from the host cell by lysis, a process that kills the cell by bursting its membrane and cell wall if present: this is a feature of many bacterial and some animal viruses. Some viruses undergo a lysogenic cycle where the viral genome is incorporated by genetic recombination into a specific place in the host's chromosome. The viral genome is then known as a "provirus" or, in the case of bacteriophages a "prophage".[119] Whenever the host divides, the viral genome is also replicated. The viral genome is mostly silent within the host. At some point, the provirus or prophage may give rise to active virus, which may lyse the host cells.[120] Enveloped viruses (e.g., HIV) typically are released from the host cell by budding. During this process the virus acquires its envelope, which is a modified piece of the host's plasma or other, internal membrane.[121]
+
+The genetic material within virus particles, and the method by which the material is replicated, varies considerably between different types of viruses.
+
+The range of structural and biochemical effects that viruses have on the host cell is extensive.[126] These are called 'cytopathic effects'.[127] Most virus infections eventually result in the death of the host cell. The causes of death include cell lysis, alterations to the cell's surface membrane and apoptosis.[128] Often cell death is caused by cessation of its normal activities because of suppression by virus-specific proteins, not all of which are components of the virus particle.[129] The distinction between cytopathic and harmless is gradual. Some viruses, such as Epstein–Barr virus, can cause cells to proliferate without causing malignancy,[130] while others, such as papillomaviruses, are established causes of cancer.[131]
+
+Some viruses cause no apparent changes to the infected cell. Cells in which the virus is latent and inactive show few signs of infection and often function normally.[132] This causes persistent infections and the virus is often dormant for many months or years. This is often the case with herpes viruses.[133][134]
+
+Viruses are by far the most abundant biological entities on Earth and they outnumber all the others put together.[135] They infect all types of cellular life including animals, plants, bacteria and fungi.[90] Different types of viruses can infect only a limited range of hosts and many are species-specific. Some, such as smallpox virus for example, can infect only one species—in this case humans,[136] and are said to have a narrow host range. Other viruses, such as rabies virus, can infect different species of mammals and are said to have a broad range.[137] The viruses that infect plants are harmless to animals, and most viruses that infect other animals are harmless to humans.[138] The host range of some bacteriophages is limited to a single strain of bacteria and they can be used to trace the source of outbreaks of infections by a method called phage typing.[139] The complete set of viruses in an organism or habitat is called the virome; for example, all human viruses constitute the human virome.[140]
+
+Classification seeks to describe the diversity of viruses by naming and grouping them on the basis of similarities. In 1962, André Lwoff, Robert Horne, and Paul Tournier were the first to develop a means of virus classification, based on the Linnaean hierarchical system.[141] This system based classification on phylum, class, order, family, genus, and species. Viruses were grouped according to their shared properties (not those of their hosts) and the type of nucleic acid forming their genomes.[142] In 1966, the International Committee on Taxonomy of Viruses (ICTV) was formed. The system proposed by Lwoff, Horne and Tournier was initially not accepted by the ICTV because the small genome size of viruses and their high rate of mutation made it difficult to determine their ancestry beyond order. As such, the Baltimore classification system has come to be used to supplement the more traditional hierarchy.[143] Starting in 2018, the ICTV began to acknowledge deeper evolutionary relationships between viruses that have been discovered over time and adopted a 15-rank classification system ranging from realm to species.[144]
+
+The ICTV developed the current classification system and wrote guidelines that put a greater weight on certain virus properties to maintain family uniformity. A unified taxonomy (a universal system for classifying viruses) has been established. Only a small part of the total diversity of viruses has been studied.[145] As of 2019, 4 realms, 9 kingdoms, 16 phyla, 2 subphyla, 36 classes, 55 orders, 8 suborders, 168 families, 103 subfamilies, 1,421 genera, 68 subgenera, and 6,589 species of viruses have been defined by the ICTV.[4]
+
+The general taxonomic structure of taxon ranges and the suffixes used in taxonomic names are shown hereafter. As of 2019, the ranks of subrealm, subkingdom, and subclass are unused, whereas all other ranks are in use.
+
+The Nobel Prize-winning biologist David Baltimore devised the Baltimore classification system.[42][146] The ICTV classification system is used in conjunction with the Baltimore classification system in modern virus classification.[147][148][149]
+
+The Baltimore classification of viruses is based on the mechanism of mRNA production. Viruses must generate mRNAs from their genomes to produce proteins and replicate themselves, but different mechanisms are used to achieve this in each virus family. Viral genomes may be single-stranded (ss) or double-stranded (ds), RNA or DNA, and may or may not use reverse transcriptase (RT). In addition, ssRNA viruses may be either sense (+) or antisense (−). This classification places viruses into seven groups:
+
+
+
+Examples of common human diseases caused by viruses include the common cold, influenza, chickenpox, and cold sores. Many serious diseases such as rabies, Ebola virus disease, AIDS (HIV), avian influenza, and SARS are caused by viruses. The relative ability of viruses to cause disease is described in terms of virulence. Other diseases are under investigation to discover if they have a virus as the causative agent, such as the possible connection between human herpesvirus 6 (HHV6) and neurological diseases such as multiple sclerosis and chronic fatigue syndrome.[151] There is controversy over whether the bornavirus, previously thought to cause neurological diseases in horses, could be responsible for psychiatric illnesses in humans.[152]
+
+Viruses have different mechanisms by which they produce disease in an organism, which depends largely on the viral species. Mechanisms at the cellular level primarily include cell lysis, the breaking open and subsequent death of the cell. In multicellular organisms, if enough cells die, the whole organism will start to suffer the effects. Although viruses cause disruption of healthy homeostasis, resulting in disease, they may exist relatively harmlessly within an organism. An example would include the ability of the herpes simplex virus, which causes cold sores, to remain in a dormant state within the human body. This is called latency[153] and is a characteristic of the herpes viruses, including Epstein–Barr virus, which causes glandular fever, and varicella zoster virus, which causes chickenpox and shingles. Most people have been infected with at least one of these types of herpes virus.[154] These latent viruses might sometimes be beneficial, as the presence of the virus can increase immunity against bacterial pathogens, such as Yersinia pestis.[155]
+
+Some viruses can cause lifelong or chronic infections, where the viruses continue to replicate in the body despite the host's defence mechanisms.[156] This is common in hepatitis B virus and hepatitis C virus infections. People chronically infected are known as carriers, as they serve as reservoirs of infectious virus.[157] In populations with a high proportion of carriers, the disease is said to be endemic.[158]
+
+Viral epidemiology is the branch of medical science that deals with the transmission and control of virus infections in humans. Transmission of viruses can be vertical, which means from mother to child, or horizontal, which means from person to person. Examples of vertical transmission include hepatitis B virus and HIV, where the baby is born already infected with the virus.[159] Another, more rare, example is the varicella zoster virus, which, although causing relatively mild infections in children and adults, can be fatal to the foetus and newborn baby.[160]
+
+Horizontal transmission is the most common mechanism of spread of viruses in populations.[161] Horizontal transmission can occur when body fluids are exchanged during sexual activity, by exchange of saliva or when contaminated food or water is ingested. It can also occur when aerosols containing viruses are inhaled or by insect vectors such as when infected mosquitoes penetrate the skin of a host.[161] Most types of viruses are restricted to just one or two of these mechanisms and they are referred to as "respiratory viruses" or "enteric viruses" and so forth. The rate or speed of transmission of viral infections depends on factors that include population density, the number of susceptible individuals, (i.e., those not immune),[162] the quality of healthcare and the weather.[163]
+
+Epidemiology is used to break the chain of infection in populations during outbreaks of viral diseases.[164] Control measures are used that are based on knowledge of how the virus is transmitted. It is important to find the source, or sources, of the outbreak and to identify the virus. Once the virus has been identified, the chain of transmission can sometimes be broken by vaccines. When vaccines are not available, sanitation and disinfection can be effective. Often, infected people are isolated from the rest of the community, and those that have been exposed to the virus are placed in quarantine.[165] To control the outbreak of foot-and-mouth disease in cattle in Britain in 2001, thousands of cattle were slaughtered.[166] Most viral infections of humans and other animals have incubation periods during which the infection causes no signs or symptoms.[167] Incubation periods for viral diseases range from a few days to weeks, but are known for most infections.[168] Somewhat overlapping, but mainly following the incubation period, there is a period of communicability—a time when an infected individual or animal is contagious and can infect another person or animal.[168] This, too, is known for many viral infections, and knowledge of the length of both periods is important in the control of outbreaks.[169] When outbreaks cause an unusually high proportion of cases in a population, community, or region, they are called epidemics. If outbreaks spread worldwide, they are called pandemics.[170]
+
+A pandemic is a worldwide epidemic. The 1918 flu pandemic, which lasted until 1919, was a category 5 influenza pandemic caused by an unusually severe and deadly influenza A virus. The victims were often healthy young adults, in contrast to most influenza outbreaks, which predominantly affect juvenile, elderly, or otherwise-weakened patients.[171] Older estimates say it killed 40–50 million people,[172] while more recent research suggests that it may have killed as many as 100 million people, or 5% of the world's population in 1918.[173]
+
+Although viral pandemics are rare events, HIV—which evolved from viruses found in monkeys and chimpanzees—has been pandemic since at least the 1980s.[174] During the 20th century there were four pandemics caused by influenza virus and those that occurred in 1918, 1957 and 1968 were severe.[175] Most researchers believe that HIV originated in sub-Saharan Africa during the 20th century;[176] it is now a pandemic, with an estimated 37.9 million people now living with the disease worldwide.[177][177] There were about 770,000 deaths from AIDS in 2018.[178] The Joint United Nations Programme on HIV/AIDS (UNAIDS) and the World Health Organization (WHO) estimate that AIDS has killed more than 25 million people since it was first recognised on 5 June 1981, making it one of the most destructive epidemics in recorded history.[179] In 2007 there were 2.7 million new HIV infections and 2 million HIV-related deaths.[180]
+
+Several highly lethal viral pathogens are members of the Filoviridae. Filoviruses are filament-like viruses that cause viral hemorrhagic fever, and include ebolaviruses and marburgviruses. Marburg virus, first discovered in 1967, attracted widespread press attention in April 2005 for an outbreak in Angola.[181] Ebola virus disease has also caused intermittent outbreaks with high mortality rates since 1976 when it was first identified. The worst and most recent one is the 2013–2016 West Africa epidemic.[182]
+
+With the exception of smallpox, most pandemics are caused by newly evolved viruses. These "emergent" viruses are usually mutants of less harmful viruses that have circulated previously either in humans or other animals.[183]
+
+Severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS)  are caused by new types of coronaviruses. Other coronaviruses are known to cause mild infections in humans,[184] so the virulence and rapid spread of SARS infections—that by July 2003 had caused around 8,000 cases and 800 deaths—was unexpected and most countries were not prepared.[185]
+
+A related coronavirus emerged in Wuhan, China in November 2019 and spread rapidly around the world. Thought to have originated in bats and subsequently named severe acute respiratory syndrome coronavirus 2, infections with the virus caused a pandemic in 2020.[186][187][188] Unprecedented restrictions in peacetime have been placed on international travel,[189] and curfews imposed in several major cities worldwide.[190]
+
+Viruses are an established cause of cancer in humans and other species. Viral cancers occur only in a minority of infected persons (or animals). Cancer viruses come from a range of virus families, including both RNA and DNA viruses, and so there is no single type of "oncovirus" (an obsolete term originally used for acutely transforming retroviruses). The development of cancer is determined by a variety of factors such as host immunity[191] and mutations in the host.[192] Viruses accepted to cause human cancers include some genotypes of human papillomavirus, hepatitis B virus, hepatitis C virus, Epstein–Barr virus, Kaposi's sarcoma-associated herpesvirus and human T-lymphotropic virus. The most recently discovered human cancer virus is a polyomavirus (Merkel cell polyomavirus) that causes most cases of a rare form of skin cancer called Merkel cell carcinoma.[193]
+Hepatitis viruses can develop into a chronic viral infection that leads to liver cancer.[194][195] Infection by human T-lymphotropic virus can lead to tropical spastic paraparesis and adult T-cell leukaemia.[196] Human papillomaviruses are an established cause of cancers of cervix, skin, anus, and penis.[197] Within the Herpesviridae, Kaposi's sarcoma-associated herpesvirus causes Kaposi's sarcoma and body-cavity lymphoma, and Epstein–Barr virus causes Burkitt's lymphoma, Hodgkin's lymphoma, B lymphoproliferative disorder, and nasopharyngeal carcinoma.[198] Merkel cell polyomavirus closely related to SV40 and mouse polyomaviruses that have been used as animal models for cancer viruses for over 50 years.[199]
+
+The body's first line of defence against viruses is the innate immune system. This comprises cells and other mechanisms that defend the host from infection in a non-specific manner. This means that the cells of the innate system recognise, and respond to, pathogens in a generic way, but, unlike the adaptive immune system, it does not confer long-lasting or protective immunity to the host.[200]
+
+RNA interference is an important innate defence against viruses.[201] Many viruses have a replication strategy that involves double-stranded RNA (dsRNA). When such a virus infects a cell, it releases its RNA molecule or molecules, which immediately bind to a protein complex called a dicer that cuts the RNA into smaller pieces. A biochemical pathway—the RISC complex—is activated, which ensures cell survival by degrading the viral mRNA. Rotaviruses have evolved to avoid this defence mechanism by not uncoating fully inside the cell, and releasing newly produced mRNA through pores in the particle's inner capsid. Their genomic dsRNA remains protected inside the core of the virion.[202][203]
+
+When the adaptive immune system of a vertebrate encounters a virus, it produces specific antibodies that bind to the virus and often render it non-infectious. This is called humoral immunity. Two types of antibodies are important. The first, called IgM, is highly effective at neutralising viruses but is produced by the cells of the immune system only for a few weeks. The second, called IgG, is produced indefinitely. The presence of IgM in the blood of the host is used to test for acute infection, whereas IgG indicates an infection sometime in the past.[204] IgG antibody is measured when tests for immunity are carried out.[205]
+
+Antibodies can continue to be an effective defence mechanism even after viruses have managed to gain entry to the host cell. A protein that is in cells, called TRIM21, can attach to the antibodies on the surface of the virus particle. This primes the subsequent destruction of the virus by the enzymes of the cell's proteosome system.[206]
+
+A second defence of vertebrates against viruses is called cell-mediated immunity and involves immune cells known as T cells. The body's cells constantly display short fragments of their proteins on the cell's surface, and, if a T cell recognises a suspicious viral fragment there, the host cell is destroyed by 'killer T' cells and the virus-specific T-cells proliferate. Cells such as the macrophage are specialists at this antigen presentation.[207] The production of interferon is an important host defence mechanism. This is a hormone produced by the body when viruses are present. Its role in immunity is complex; it eventually stops the viruses from reproducing by killing the infected cell and its close neighbours.[208]
+
+Not all virus infections produce a protective immune response in this way. HIV evades the immune system by constantly changing the amino acid sequence of the proteins on the surface of the virion. This is known as "escape mutation" as the viral epitopes escape recognition by the host immune response. These persistent viruses evade immune control by sequestration, blockade of antigen presentation, cytokine resistance, evasion of natural killer cell activities, escape from apoptosis, and antigenic shift.[209] Other viruses, called 'neurotropic viruses', are disseminated by neural spread where the immune system may be unable to reach them.
+
+Because viruses use vital metabolic pathways within host cells to replicate, they are difficult to eliminate without using drugs that cause toxic effects to host cells in general. The most effective medical approaches to viral diseases are vaccinations to provide immunity to infection, and antiviral drugs that selectively interfere with viral replication.
+
+Vaccination is a cheap and effective way of preventing infections by viruses. Vaccines were used to prevent viral infections long before the discovery of the actual viruses. Their use has resulted in a dramatic decline in morbidity (illness) and mortality (death) associated with viral infections such as polio, measles, mumps and rubella.[210] Smallpox infections have been eradicated.[211] Vaccines are available to prevent over thirteen viral infections of humans,[212] and more are used to prevent viral infections of animals.[213] Vaccines can consist of live-attenuated or killed viruses, or viral proteins (antigens).[214] Live vaccines contain weakened forms of the virus, which do not cause the disease but, nonetheless, confer immunity. Such viruses are called attenuated. Live vaccines can be dangerous when given to people with a weak immunity (who are described as immunocompromised), because in these people, the weakened virus can cause the original disease.[215] Biotechnology and genetic engineering techniques are used to produce subunit vaccines. These vaccines use only the capsid proteins of the virus. Hepatitis B vaccine is an example of this type of vaccine.[216] Subunit vaccines are safe for immunocompromised patients because they cannot cause the disease.[217] The yellow fever virus vaccine, a live-attenuated strain called 17D, is probably the safest and most effective vaccine ever generated.[218]
+
+Antiviral drugs are often nucleoside analogues (fake DNA building-blocks), which viruses mistakenly incorporate into their genomes during replication. The life-cycle of the virus is then halted because the newly synthesised DNA is inactive. This is because these analogues lack the hydroxyl groups, which, along with phosphorus atoms, link together to form the strong "backbone" of the DNA molecule. This is called DNA chain termination.[219] Examples of nucleoside analogues are aciclovir for Herpes simplex virus infections and lamivudine for HIV and hepatitis B virus infections. Aciclovir is one of the oldest and most frequently prescribed antiviral drugs.[220]
+Other antiviral drugs in use target different stages of the viral life cycle. HIV is dependent on a proteolytic enzyme called the HIV-1 protease for it to become fully infectious. There is a large class of drugs called protease inhibitors that inactivate this enzyme.[221]
+
+Hepatitis C is caused by an RNA virus. In 80% of people infected, the disease is chronic, and without treatment, they are infected for the remainder of their lives. There is now an effective treatment that uses the nucleoside analogue drug ribavirin combined with interferon.[222] The treatment of chronic carriers of the hepatitis B virus by using a similar strategy using lamivudine has been developed.[223]
+
+Viruses infect all cellular life and, although viruses occur universally, each cellular species has its own specific range that often infect only that species.[224] Some viruses, called satellites, can replicate only within cells that have already been infected by another virus.[60]
+
+Viruses are important pathogens of livestock. Diseases such as foot-and-mouth disease and bluetongue are caused by viruses.[225] Companion animals such as cats, dogs, and horses, if not vaccinated, are susceptible to serious viral infections. Canine parvovirus is caused by a small DNA virus and infections are often fatal in pups.[226] Like all invertebrates, the honey bee is susceptible to many viral infections.[227] Most viruses co-exist harmlessly in their host and cause no signs or symptoms of disease.[3]
+
+There are many types of plant virus, but often they cause only a loss of yield, and it is not economically viable to try to control them. Plant viruses are often spread from plant to plant by organisms, known as vectors. These are usually insects, but some fungi, nematode worms, and single-celled organisms have been shown to be vectors. When control of plant virus infections is considered economical, for perennial fruits, for example, efforts are concentrated on killing the vectors and removing alternate hosts such as weeds.[228] Plant viruses cannot infect humans and other animals because they can reproduce only in living plant cells.[229]
+
+Originally from Peru, the potato has become a staple crop worldwide.[230] The potato virus Y causes disease in potatoes and related species including tomatoes and peppers. In the 1980s, this virus acquired economical importance when it proved difficult to control in seed potato crops. Transmitted by aphids, this virus can reduce crop yields by up to 80 per cent, causing significant losses to potato yields.[231]
+
+Plants have elaborate and effective defence mechanisms against viruses. One of the most effective is the presence of so-called resistance (R) genes. Each R gene confers resistance to a particular virus by triggering localised areas of cell death around the infected cell, which can often be seen with the unaided eye as large spots. This stops the infection from spreading.[232] RNA interference is also an effective defence in plants.[233] When they are infected, plants often produce natural disinfectants that kill viruses, such as salicylic acid, nitric oxide, and reactive oxygen molecules.[234]
+
+Plant virus particles or virus-like particles (VLPs) have applications in both biotechnology and nanotechnology. The capsids of most plant viruses are simple and robust structures and can be produced in large quantities either by the infection of plants or by expression in a variety of heterologous systems. Plant virus particles can be modified genetically and chemically to encapsulate foreign material and can be incorporated into supramolecular structures for use in biotechnology.[235]
+
+Bacteriophages are a common and diverse group of viruses and are the most abundant biological entity in aquatic environments—there are up to ten times more of these viruses in the oceans than there are bacteria,[236] reaching levels of 250,000,000 bacteriophages per millilitre of seawater.[237] These viruses infect specific bacteria by binding to surface receptor molecules and then entering the cell. Within a short amount of time, in some cases just minutes, bacterial polymerase starts translating viral mRNA into protein. These proteins go on to become either new virions within the cell, helper proteins, which help assembly of new virions, or proteins involved in cell lysis. Viral enzymes aid in the breakdown of the cell membrane, and, in the case of the T4 phage, in just over twenty minutes after injection over three hundred phages could be released.[238]
+
+The major way bacteria defend themselves from bacteriophages is by producing enzymes that destroy foreign DNA. These enzymes, called restriction endonucleases, cut up the viral DNA that bacteriophages inject into bacterial cells.[239] Bacteria also contain a system that uses CRISPR sequences to retain fragments of the genomes of viruses that the bacteria have come into contact with in the past, which allows them to block the virus's replication through a form of RNA interference.[240][241] This genetic system provides bacteria with acquired immunity to infection.[242]
+
+Some viruses replicate within archaea: these are double-stranded DNA viruses with unusual and sometimes unique shapes.[6][89] These viruses have been studied in most detail in the thermophilic archaea, particularly the orders Sulfolobales and Thermoproteales.[243] Defences against these viruses involve RNA interference from repetitive DNA sequences within archaean genomes that are related to the genes of the viruses.[244][245] Most archaea have CRISPR–Cas systems as an adaptive defence against viruses. These enable archaea to retain sections of viral DNA, which are then used to target and eliminate subsequent infections by the virus using a process similar to RNA interference.[246]
+
+Viruses are the most abundant biological entity in aquatic environments[2] There are about ten million of them in a teaspoon of seawater.[247] Most of these viruses are bacteriophages infecting heterotrophic bacteria and cyanophages infecting cyanobacteria and they are essential to the regulation of saltwater and freshwater ecosystems.[248]
+Bacteriophages are harmless to plants and animals, and are essential to the regulation of marine and freshwater ecosystems[249]  are  important mortality agents of phytoplankton, the base of the foodchain in aquatic environments.[250] They infect and destroy bacteria in aquatic microbial communities, and are one of the most important mechanisms of recycling carbon and nutrient cycling in marine environments. The organic molecules released from the dead bacterial cells stimulate fresh bacterial and algal growth, in a process known as the viral shunt.[251] In particular, lysis of bacteria by viruses has been shown to enhance nitrogen cycling and stimulate phytoplankton growth.[252]  Viral activity may also affect the biological pump, the process whereby carbon is sequestered in the deep ocean.[253]
+
+Microorganisms constitute more than 90% of the biomass in the sea. It is estimated that viruses kill approximately 20% of this biomass each day and that there are 10 to 15 times as many viruses in the oceans as there are bacteria and archaea.[254] Viruses are also major agents responsible for the destruction of phytoplankton including harmful algal blooms,[255]
+The number of viruses in the oceans decreases further offshore and deeper into the water, where there are fewer host organisms.[253]
+
+In January 2018, scientists reported that 800 million viruses, mainly of marine origin, are deposited daily from the Earth's atmosphere onto every square meter of the planet's surface, as the result of a global atmospheric stream of viruses, circulating above the weather system but below the altitude of usual airline travel, distributing viruses around the planet.[256][257]
+
+Like any organism, marine mammals are susceptible to viral infections. In 1988 and 2002, thousands of harbour seals were killed in Europe by phocine distemper virus.[258] Many other viruses, including caliciviruses, herpesviruses, adenoviruses and parvoviruses, circulate in marine mammal populations.[253]
+
+Viruses are an important natural means of transferring genes between different species, which increases genetic diversity and drives evolution.[8] It is thought that viruses played a central role in early evolution, before the diversification of the last universal common ancestor into bacteria, archaea and eukaryotes.[259] Viruses are still one of the largest reservoirs of unexplored genetic diversity on Earth.[253]
+
+Viruses are important to the study of molecular and cell biology as they provide simple systems that can be used to manipulate and investigate the functions of cells.[260] The study and use of viruses have provided valuable information about aspects of cell biology.[261] For example, viruses have been useful in the study of genetics and helped our understanding of the basic mechanisms of molecular genetics, such as DNA replication, transcription, RNA processing, translation, protein transport, and immunology.
+
+Geneticists often use viruses as vectors to introduce genes into cells that they are studying. This is useful for making the cell produce a foreign substance, or to study the effect of introducing a new gene into the genome. In a similar fashion, virotherapy uses viruses as vectors to treat various diseases, as they can specifically target cells and DNA. It shows promising use in the treatment of cancer and in gene therapy. Eastern European scientists have used phage therapy as an alternative to antibiotics for some time, and interest in this approach is increasing, because of the high level of antibiotic resistance now found in some pathogenic bacteria.[262]
+The expression of heterologous proteins by viruses is the basis of several manufacturing processes that are currently being used for the production of various proteins such as vaccine antigens and antibodies. Industrial processes have been recently developed using viral vectors and a number of pharmaceutical proteins are currently in pre-clinical and clinical trials.[263]
+
+Virotherapy involves the use of genetically modified viruses to treat diseases.[264] Viruses have been modified by scientists to reproduce in cancer cells and destroy them but not infect healthy cells. Talimogene laherparepvec (T-VEC), for example, is a modified herpes simplex virus that has had a gene, which is required for viruses to replicate in healthy cells, deleted and replaced with a human gene (GM-CSF) that stimulates immunity. When this virus infects cancer cells, it destroys them and in doing so the presence the GM-CSF gene attracts dendritic cells from the surrounding tissues of the body. The dendritic cells process the dead cancer cells and present components of them to other cells of the immune system.[265] Having completed successful clinical trials, the virus gained approval for the treatment of melanoma in late 2015.[266] Viruses that have been reprogrammed to kill cancer cells are called oncolytic viruses.[267]
+
+Current trends in nanotechnology promise to make much more versatile use of viruses. From the viewpoint of a materials scientist, viruses can be regarded as organic nanoparticles.
+Their surface carries specific tools that enable them to cross the barriers of their host cells. The size and shape of viruses and the number and nature of the functional groups on their surface is precisely defined. As such, viruses are commonly used in materials science as scaffolds for covalently linked surface modifications. A particular quality of viruses is that they can be tailored by directed evolution. The powerful techniques developed by life sciences are becoming the basis of engineering approaches towards nanomaterials, opening a wide range of applications far beyond biology and medicine.[268]
+
+Because of their size, shape, and well-defined chemical structures, viruses have been used as templates for organising materials on the nanoscale. Recent examples include work at the Naval Research Laboratory in Washington, D.C., using Cowpea mosaic virus (CPMV) particles to amplify signals in DNA microarray based sensors. In this application, the virus particles separate the fluorescent dyes used for signalling to prevent the formation of non-fluorescent dimers that act as quenchers.[269] Another example is the use of CPMV as a nanoscale breadboard for molecular electronics.[270]
+
+Many viruses can be synthesised de novo ("from scratch") and the first synthetic virus was created in 2002.[271] Although somewhat of a misconception, it is not the actual virus that is synthesised, but rather its DNA genome (in case of a DNA virus), or a cDNA copy of its genome (in case of RNA viruses). For many virus families the naked synthetic DNA or RNA (once enzymatically converted back from the synthetic cDNA) is infectious when introduced into a cell. That is, they contain all the necessary information to produce new viruses. This technology is now being used to investigate novel vaccine strategies.[272] The ability to synthesise viruses has far-reaching consequences, since viruses can no longer be regarded as extinct, as long as the information of their genome sequence is known and permissive cells are available. As of November 2017[update], the full-length genome sequences of 7454 different viruses, including smallpox, are publicly available in an online database maintained by the National Institutes of Health.[273]
+
+The ability of viruses to cause devastating epidemics in human societies has led to the concern that viruses could be weaponised for biological warfare. Further concern was raised by the successful recreation of the infamous 1918 influenza virus in a laboratory.[274]
+Smallpox virus devastated numerous societies throughout history before its eradication. There are only two centres in the world authorised by the WHO to keep stocks of smallpox virus: the State Research Center of Virology and Biotechnology VECTOR in Russia and the Centers for Disease Control and Prevention in the United States.[275] It may be used as a weapon,[275] as the vaccine for smallpox sometimes had severe side-effects, it is no longer used routinely in any country. Thus, much of the modern human population has almost no established resistance to smallpox and would be vulnerable to the virus.[275]
+

en/601.html.txt

@@ -0,0 +1,116 @@
+
+
+An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917, but was not recognized as such.[4] The first confirmation of detection occurred in 1992. This was followed by the confirmation of a different planet, originally detected in 1988. As of 1 July 2020, there are 4,281 confirmed exoplanets in 3,163 systems, with 701 systems having more than one planet.[5]
+
+There are many methods of detecting exoplanets. Transit photometry and Doppler spectroscopy have found the most, but these methods suffer from a clear observational bias favoring the detection of planets near the star; thus, 85% of the exoplanets detected are inside the tidal locking zone.[6] In several cases, multiple planets have been observed around a star.[7] About 1 in 5 Sun-like stars[a] have an "Earth-sized"[b] planet in the habitable zone.[c][8][9] Assuming there are 200 billion stars in the Milky Way,[d] it can be hypothesized that there are 11 billion potentially habitable Earth-sized planets in the Milky Way, rising to 40 billion if planets orbiting the numerous red dwarfs are included.[10]
+
+The least massive planet known is Draugr (also known as PSR B1257+12 A or PSR B1257+12 b), which is about twice the mass of the Moon. The most massive planet listed on the NASA Exoplanet Archive is HR 2562 b,[11][12] about 30 times the mass of Jupiter, although according to some definitions of a planet (based on the nuclear fusion of deuterium[13]), it is too massive to be a planet and may be a brown dwarf instead. Known orbital times for exoplanets vary from a few hours (for those closest to their star) to thousands of years. Some exoplanets are so far away from the star that it is difficult to tell whether they are gravitationally bound to it. Almost all of the planets detected so far are within the Milky Way. There is evidence that extragalactic planets, exoplanets farther away in galaxies beyond the local Milky Way galaxy, may exist.[14][15] The nearest exoplanet is Proxima Centauri b, located 4.2 light-years (1.3 parsecs) from Earth and orbiting Proxima Centauri, the closest star to the Sun.[16]
+
+The discovery of exoplanets has intensified interest in the search for extraterrestrial life. There is special interest in planets that orbit in a star's habitable zone, where it is possible for liquid water, a prerequisite for life on Earth, to exist on the surface. The study of planetary habitability also considers a wide range of other factors in determining the suitability of a planet for hosting life.[17]
+
+Rogue planets do not orbit any star. Such objects are considered as a separate category of planet, especially if they are gas giants, which are often counted as sub-brown dwarfs.[18] The rogue planets in the Milky Way possibly number in the billions or more.[19][20]
+
+The convention for designating exoplanets is an extension of the system used for designating multiple-star systems as adopted by the International Astronomical Union (IAU). For exoplanets orbiting a single star, the IAU designation is formed by taking the designated or proper name of its parent star, and adding a lower case letter.[22] Letters are given in order of each planet's discovery around the parent star, so that the first planet discovered in a system is designated "b" (the parent star is considered to be "a") and later planets are given subsequent letters. If several planets in the same system are discovered at the same time, the closest one to the star gets the next letter, followed by the other planets in order of orbital size. A provisional IAU-sanctioned standard exists to accommodate the designation of circumbinary planets. A limited number of exoplanets have IAU-sanctioned proper names. Other naming systems exist.
+
+For centuries scientists, philosophers, and science fiction writers suspected that extrasolar planets existed, but there was no way of knowing whether they existed, how common they were, or how similar they might be to the planets of the Solar System. Various detection claims made in the nineteenth century were rejected by astronomers.
+
+The first evidence of a possible exoplanet, orbiting Van Maanen 2, was noted in 1917, but was not recognized as such. The astronomer Walter Sydney Adams, who later became director of the Mount Wilson Observatory, produced a spectrum of the star using Mount Wilson's 60-inch telescope. He interpreted the spectrum to be of an F-type main-sequence star, but it is now thought that such a spectrum could be caused by the residue of a nearby exoplanet that had been pulverized into dust by the gravity of the star, the resulting dust then falling onto the star.[4]
+
+The first suspected scientific detection of an exoplanet occurred in 1988. Shortly afterwards, the first confirmation of detection came in 1992, with the discovery of several terrestrial-mass planets orbiting the pulsar PSR B1257+12.[23] The first confirmation of an exoplanet orbiting a main-sequence star was made in 1995, when a giant planet was found in a four-day orbit around the nearby star 51 Pegasi. Some exoplanets have been imaged directly by telescopes, but the vast majority have been detected through indirect methods, such as the transit method and the radial-velocity method. In February 2018, researchers using the Chandra X-ray Observatory, combined with a planet detection technique called microlensing, found evidence of planets in a distant galaxy, stating "Some of these exoplanets are as (relatively) small as the moon, while others are as massive as Jupiter. Unlike Earth, most of the exoplanets are not tightly bound to stars, so they're actually wandering through space or loosely orbiting between stars. We can estimate that the number of planets in this [faraway] galaxy is more than a trillion.[24]
+
+This space we declare to be infinite... In it are an infinity of worlds of the same kind as our own.
+
+In the sixteenth century, the Italian philosopher Giordano Bruno, an early supporter of the Copernican theory that Earth and other planets orbit the Sun (heliocentrism), put forward the view that the fixed stars are similar to the Sun and are likewise accompanied by planets.
+
+In the eighteenth century, the same possibility was mentioned by Isaac Newton in the "General Scholium" that concludes his Principia. Making a comparison to the Sun's planets, he wrote "And if the fixed stars are the centres of similar systems, they will all be constructed according to a similar design and subject to the dominion of One."[26]
+
+In 1952, more than 40 years before the first hot Jupiter was discovered, Otto Struve wrote that there is no compelling reason why planets could not be much closer to their parent star than is the case in the Solar System, and proposed that Doppler spectroscopy and the transit method could detect super-Jupiters in short orbits.[27]
+
+Claims of exoplanet detections have been made since the nineteenth century. Some of the earliest involve the binary star 70 Ophiuchi. In 1855 William Stephen Jacob at the East India Company's Madras Observatory reported that orbital anomalies made it "highly probable" that there was a "planetary body" in this system.[28] In the 1890s, Thomas J. J. See of the University of Chicago and the United States Naval Observatory stated that the orbital anomalies proved the existence of a dark body in the 70 Ophiuchi system with a 36-year period around one of the stars.[29] However, Forest Ray Moulton published a paper proving that a three-body system with those orbital parameters would be highly unstable.[30] During the 1950s and 1960s, Peter van de Kamp of Swarthmore College made another prominent series of detection claims, this time for planets orbiting Barnard's Star.[31] Astronomers now generally regard all the early reports of detection as erroneous.[32]
+
+In 1991 Andrew Lyne, M. Bailes and S. L. Shemar claimed to have discovered a pulsar planet in orbit around PSR 1829-10, using pulsar timing variations.[33] The claim briefly received intense attention, but Lyne and his team soon retracted it.[34]
+
+As of 1 July 2020, a total of 4,281 confirmed exoplanets are listed in the Extrasolar Planets Encyclopedia, including a few that were confirmations of controversial claims from the late 1980s.[5]  The first published discovery to receive subsequent confirmation was made in 1988 by the Canadian astronomers Bruce Campbell, G. A. H. Walker, and Stephenson Yang of the University of Victoria and the University of British Columbia.[35] Although they were cautious about claiming a planetary detection, their radial-velocity observations suggested that a planet orbits the star Gamma Cephei. Partly because the observations were at the very limits of instrumental capabilities at the time, astronomers remained skeptical for several years about this and other similar observations. It was thought some of the apparent planets might instead have been brown dwarfs, objects intermediate in mass between planets and stars. In 1990, additional observations were published that supported the existence of the planet orbiting Gamma Cephei,[36] but subsequent work in 1992 again raised serious doubts.[37] Finally, in 2003, improved techniques allowed the planet's existence to be confirmed.[38]
+
+On 9 January 1992, radio astronomers Aleksander Wolszczan and Dale Frail announced the discovery of two planets orbiting the pulsar PSR 1257+12.[23] This discovery was confirmed, and is generally considered to be the first definitive detection of exoplanets. Follow-up observations solidified these results, and confirmation of a third planet in 1994 revived the topic in the popular press.[39] These pulsar planets are thought to have formed from the unusual remnants of the supernova that produced the pulsar, in a second round of planet formation, or else to be the remaining rocky cores of gas giants that somehow survived the supernova and then decayed into their current orbits.
+
+On 6 October 1995, Michel Mayor and Didier Queloz of the University of Geneva announced the first definitive detection of an exoplanet orbiting a main-sequence star, nearby G-type star 51 Pegasi.[40][41] This discovery, made at the Observatoire de Haute-Provence, ushered in the modern era of exoplanetary discovery, and was recognized by a share of the 2019 Nobel Prize in Physics. Technological advances, most notably in high-resolution spectroscopy, led to the rapid detection of many new exoplanets: astronomers could detect exoplanets indirectly by measuring their gravitational influence on the motion of their host stars. More extrasolar planets were later detected by observing the variation in a star's apparent luminosity as an orbiting planet transited in front of it.
+
+Initially, most known exoplanets were massive planets that orbited very close to their parent stars. Astronomers were surprised by these "hot Jupiters", because theories of planetary formation had indicated that giant planets should only form at large distances from stars. But eventually more planets of other sorts were found, and it is now clear that hot Jupiters make up the minority of exoplanets. In 1999, Upsilon Andromedae became the first main-sequence star known to have multiple planets.[42] Kepler-16 contains the first discovered planet that orbits around a binary main-sequence star system.[43]
+
+On 26 February 2014, NASA announced the discovery of 715 newly verified exoplanets around 305 stars by the Kepler Space Telescope. These exoplanets were checked using a statistical technique called "verification by multiplicity".[44][45][46] Before these results, most confirmed planets were gas giants comparable in size to Jupiter or larger because they are more easily detected, but the Kepler planets are mostly between the size of Neptune and the size of Earth.[44]
+
+On 23 July 2015, NASA announced Kepler-452b, a near-Earth-size planet orbiting the habitable zone of a G2-type star.[47]
+
+On 6 September 2018, NASA discovered an exoplanet about 145 light years away from Earth in the constellation Virgo.[48] This exoplanet, Wolf 503b, is twice the size of Earth and was discovered orbiting a type of star known as an "Orange Dwarf". Wolf 503b completes one orbit in as few as six days because it is very close to the star. Wolf 503b is the only exoplanet that large that can be found near the so-called Fulton gap. The Fulton gap, first noticed in 2017, is the observation that it is unusual to find planets within a certain mass range.[48] Under the Fulton gap studies, this opens up a new field for astronomers, who are still studying whether planets found in the Fulton gap are gaseous or rocky.[48]
+
+In January 2020, scientists announced the discovery of TOI 700 d, the first Earth-sized planet in the habitable zone detected by TESS.[49]
+
+As of January 2020, NASA's Kepler and TESS missions had identified 4374 planetary candidates yet to be confirmed,[50] several of them being nearly Earth-sized and located in the habitable zone, some around Sun-like stars.[51][52][53]
+
+About 97% of all the confirmed exoplanets have been discovered by indirect techniques of detection, mainly by radial velocity measurements and transit monitoring techniques.[57] Recently the techniques of singular optics have been applied in the search for exoplanets.[58]
+
+Planets may form within a few to tens (or more) of millions of years of their star forming.[59][60][61][62][63] 
+The planets of the Solar System can only be observed in their current state, but observations of different planetary systems of varying ages allows us to observe planets at different stages of evolution. Available observations range from young proto-planetary disks where planets are still forming[64] to planetary systems of over 10 Gyr old.[65] When planets form in a gaseous protoplanetary disk,[66] they accrete hydrogen/helium envelopes.[67][68] These envelopes cool and contract over time and, depending on the mass of the planet, some or all of the hydrogen/helium is eventually lost to space.[66] This means that even terrestrial planets may start off with large radii if they form early enough.[69][70][71] An example is Kepler-51b which has only about twice the mass of Earth but is almost the size of Saturn which is a hundred times the mass of Earth. Kepler-51b is quite young at a few hundred million years old.[72]
+
+There is at least one planet on average per star.[7]
+About 1 in 5 Sun-like stars[a] have an "Earth-sized"[b] planet in the habitable zone.[74]
+
+Most known exoplanets orbit stars roughly similar to the Sun, i.e. main-sequence stars of spectral categories F, G, or K. Lower-mass stars (red dwarfs, of spectral category M) are less likely to have planets massive enough to be detected by the radial-velocity method.[75][76] Despite this, several tens of planets around red dwarfs have been discovered by the Kepler spacecraft, which uses the transit method to detect smaller planets.
+
+Using data from Kepler, a correlation has been found between the metallicity of a star and the probability that the star host planets. Stars with higher metallicity are more likely to have planets, especially giant planets, than stars with lower metallicity.[77]
+
+Some planets orbit one member of a binary star system,[78] and several circumbinary planets have been discovered which orbit around both members of binary star. A few planets in triple star systems are known[79] and one in the quadruple system Kepler-64.
+
+In 2013 the color of an exoplanet was determined for the first time. The best-fit albedo measurements of HD 189733b suggest that it is deep dark blue.[80][81] Later that same year, the colors of several other exoplanets were determined, including GJ 504 b which visually has a magenta color,[82] and Kappa Andromedae b, which if seen up close would appear reddish in color.[83]
+Helium planets are expected to be white or grey in appearance.[84]
+
+The apparent brightness (apparent magnitude) of a planet depends on how far away the observer is, how reflective the planet is (albedo), and how much light the planet receives from its star, which depends on how far the planet is from the star and how bright the star is. So, a planet with a low albedo that is close to its star can appear brighter than a planet with high albedo that is far from the star.[85]
+
+The darkest known planet in terms of geometric albedo is TrES-2b, a hot Jupiter that reflects less than 1% of the light from its star, making it less reflective than coal or black acrylic paint. Hot Jupiters are expected to be quite dark due to sodium and potassium in their atmospheres but it is not known why TrES-2b is so dark—it could be due to an unknown chemical compound.[86][87][88]
+
+For gas giants, geometric albedo generally decreases with increasing metallicity or atmospheric temperature unless there are clouds to modify this effect. Increased cloud-column depth increases the albedo at optical wavelengths, but decreases it at some infrared wavelengths. Optical albedo increases with age, because older planets have higher cloud-column depths. Optical albedo decreases with increasing mass, because higher-mass giant planets have higher surface gravities, which produces lower cloud-column depths. Also, elliptical orbits can cause major fluctuations in atmospheric composition, which can have a significant effect.[89]
+
+There is more thermal emission than reflection at some near-infrared wavelengths for massive and/or young gas giants. So, although optical brightness is fully phase-dependent, this is not always the case in the near infrared.[89]
+
+Temperatures of gas giants reduce over time and with distance from their star. Lowering the temperature increases optical albedo even without clouds. At a sufficiently low temperature, water clouds form, which further increase optical albedo. At even lower temperatures ammonia clouds form, resulting in the highest albedos at most optical and near-infrared wavelengths.[89]
+
+In 2014, a magnetic field around HD 209458 b was inferred from the way hydrogen was evaporating from the planet. It is the first (indirect) detection of a magnetic field on an exoplanet. The magnetic field is estimated to be about one tenth as strong as Jupiter's.[90][91]
+
+Exoplanets magnetic fields may be detectable by their auroral radio emissions with sensitive enough radio telescopes such as LOFAR.[92][93] The radio emissions could enable determination of the rotation rate of the interior of an exoplanet, and may yield a more accurate way to measure exoplanet rotation than by examining the motion of clouds.[94]
+
+Earth's magnetic field results from its flowing liquid metallic core, but in massive super-Earths with high pressure, different compounds may form which do not match those created under terrestrial conditions. Compounds may form with greater viscosities and high melting temperatures which could prevent the interiors from separating into different layers and so result in undifferentiated coreless mantles. Forms of magnesium oxide such as MgSi3O12 could be a liquid metal at the pressures and temperatures found in super-Earths and could generate a magnetic field in the mantles of super-Earths.[95][96]
+
+Hot Jupiters have been observed to have a larger radius than expected. This could be caused by the interaction between the stellar wind and the planet's magnetosphere creating an electric current through the planet that heats it up causing it to expand. The more magnetically active a star is the greater the stellar wind and the larger the electric current leading to more heating and expansion of the planet. This theory matches the observation that stellar activity is correlated with inflated planetary radii.[97]
+
+In August 2018, scientists announced the transformation of gaseous deuterium into a liquid metallic form. This may help researchers better understand giant gas planets, such as Jupiter, Saturn and related exoplanets, since such planets are thought to contain a lot of liquid metallic hydrogen, which may be responsible for their observed powerful magnetic fields.[98][99]
+
+Although scientists previously announced that the magnetic fields of close-in exoplanets may cause increased stellar flares and starspots on their host stars, in 2019 this claim was demonstrated to be false in the HD 189733 system.  The failure to detect "star-planet interactions" in the well-studied HD 189733 system calls other related claims of the effect into question.[100]
+
+In 2019 the strength of the surface magnetic fields of 4 hot Jupiters were estimated and ranged between 20 and 120 gauss compared to Jupiter's surface magnetic field of 4.3 gauss.[101][102]
+
+In 2007, two independent teams of researchers came to opposing conclusions about the likelihood of plate tectonics on larger super-Earths[103][104] with one team saying that plate tectonics would be episodic or stagnant[105] and the other team saying that plate tectonics is very likely on super-Earths even if the planet is dry.[106]
+
+If super-Earths have more than 80 times as much water as Earth then they become ocean planets with all land completely submerged. However, if there is less water than this limit, then the deep water cycle will move enough water between the oceans and mantle to allow continents to exist.[107][108]
+
+Large surface temperature variations on 55 Cancri e have been attributed to possible volcanic activity releasing large clouds of dust which blanket the planet and block thermal emissions.[109][110]
+
+The star 1SWASP J140747.93-394542.6 is orbited by an object that is circled by a ring system much larger than Saturn's rings. However, the mass of the object is not known; it could be a brown dwarf or low-mass star instead of a planet.[111][112]
+
+The brightness of optical images of Fomalhaut b could be due to starlight reflecting off a circumplanetary ring system with a radius between 20 and 40 times that of Jupiter's radius, about the size of the orbits of the Galilean moons.[113]
+
+The rings of the Solar System's gas giants are aligned with their planet's equator. However, for exoplanets that orbit close to their star, tidal forces from the star would lead to the outermost rings of a planet being aligned with the planet's orbital plane around the star. A planet's innermost rings would still be aligned with the planet's equator so that if the planet has a tilted rotational axis, then the different alignments between the inner and outer rings would create a warped ring system.[114]
+
+In December 2013 a candidate exomoon of a rogue planet was announced.[115] On 3 October 2018, evidence suggesting a large exomoon orbiting Kepler-1625b was reported.[116]
+
+Atmospheres have been detected around several exoplanets. The first to be observed was HD 209458 b in 2001.[118]
+
+In May 2017, glints of light from Earth, seen as twinkling from an orbiting satellite a million miles away, were found to be reflected light from ice crystals in the atmosphere.[119][120] The technology used to determine this may be useful in studying the atmospheres of distant worlds, including those of exoplanets.
+
+KIC 12557548 b is a small rocky planet, very close to its star, that is evaporating and leaving a trailing tail of cloud and dust like a comet.[121] The dust could be ash erupting from volcanos and escaping due to the small planet's low surface-gravity, or it could be from metals that are vaporized by the high temperatures of being so close to the star with the metal vapor then condensing into dust.[122]
+
+In June 2015, scientists reported that the atmosphere of GJ 436 b was evaporating, resulting in a giant cloud around the planet and, due to radiation from the host star, a long trailing tail 14 million km (9 million mi) long.[123]
+
+Tidally locked planets in a 1:1 spin-orbit resonance would have their star always shining directly overhead on one spot which would be hot with the opposite hemisphere receiving no light and being freezing cold. Such a planet could resemble an eyeball with the hotspot being the pupil.[124] Planets with an eccentric orbit could be locked in other resonances. 3:2 and 5:2 resonances would result in a double-eyeball pattern with hotspots in both eastern and western hemispheres.[125] Planets with both an eccentric orbit and a tilted axis of rotation would have more complicated insolation patterns.[126]
+
+As more planets are discovered, the field of exoplanetology continues to grow into a deeper study of extrasolar worlds, and will ultimately tackle the prospect of life on planets beyond the Solar System.[57] At cosmic distances, life can only be detected if it is developed at a planetary scale and strongly modified the planetary environment, in such a way that the modifications cannot be explained by classical physico-chemical processes (out of equilibrium processes).[57] For example, molecular oxygen (O2) in the atmosphere of Earth is a result of photosynthesis by living plants and many kinds of microorganisms, so it can be used as an indication of life on exoplanets, although small amounts of oxygen could also be produced by non-biological means.[127] Furthermore, a potentially habitable planet must orbit a stable star at a distance within which planetary-mass objects with sufficient atmospheric pressure can support liquid water at their surfaces.[128][129]

en/6010.html.txt

@@ -0,0 +1,149 @@
+
+
+Archimedes of Syracuse (/ˌɑːrkɪˈmiːdiːz/;[2] Ancient Greek: Ἀρχιμήδης, Arkhimḗdēs; Doric Greek: [ar.kʰi.mɛː.dɛ̂ːs]; c. 287 – c. 212 BC) was a Greek mathematician, physicist, engineer, inventor, and astronomer.[3] Although few details of his life are known, he is regarded as one of the leading scientists in classical antiquity. Considered to be the greatest mathematician of ancient history, and one of the greatest of all time,[4][5][6][7][8][9] Archimedes anticipated modern calculus and analysis by applying concepts of infinitesimals and the method of exhaustion to derive and rigorously prove a range of geometrical theorems, including: the area of a circle; the surface area and volume of a sphere; area of an ellipse; the area under a parabola; the volume of a segment of a paraboloid of revolution; the volume of a segment of a hyperboloid of revolution; and the area of a spiral.[10][11]
+
+Other mathematical achievements include deriving an accurate approximation of pi; defining and investigating the spiral that now bears his name; and creating a system using exponentiation for expressing very large numbers. He was also one of the first to apply mathematics to physical phenomena, founding hydrostatics and statics, including an explanation of the principle of the lever. He is credited with designing innovative machines, such as his screw pump, compound pulleys, and defensive war machines to protect his native Syracuse from invasion.
+
+Archimedes died during the Siege of Syracuse, where he was killed by a Roman soldier despite orders that he should not be harmed. Cicero describes visiting the tomb of Archimedes, which was surmounted by a sphere and a cylinder, which Archimedes had requested be placed on his tomb to represent his mathematical discoveries.
+
+Unlike his inventions, the mathematical writings of Archimedes were little known in antiquity. Mathematicians from Alexandria read and quoted him, but the first comprehensive compilation was not made until c. 530 AD by Isidore of Miletus in Byzantine Constantinople, while commentaries on the works of Archimedes written by Eutocius in the 6th century AD opened them to wider readership for the first time. The relatively few copies of Archimedes' written work that survived through the Middle Ages were an influential source of ideas for scientists during the Renaissance, while the discovery in 1906 of previously unknown works by Archimedes in the Archimedes Palimpsest has provided new insights into how he obtained mathematical results.[12][13][14]
+
+Archimedes was born c. 287 BC in the seaport city of Syracuse, Sicily, at that time a self-governing colony in Magna Graecia. The date of birth is based on a statement by the Byzantine Greek historian John Tzetzes that Archimedes lived for 75 years.[11] In The Sand Reckoner, Archimedes gives his father's name as Phidias, an astronomer about whom nothing else is known. Plutarch wrote in his Parallel Lives that Archimedes was related to King Hiero II, the ruler of Syracuse.[15] A biography of Archimedes was written by his friend Heracleides, but this work has been lost, leaving the details of his life obscure.[16] It is unknown, for instance, whether he ever married or had children. During his youth, Archimedes may have studied in Alexandria, Egypt, where Conon of Samos and Eratosthenes of Cyrene were contemporaries. He referred to Conon of Samos as his friend, while two of his works (The Method of Mechanical Theorems and the Cattle Problem) have introductions addressed to Eratosthenes.[a]
+
+Archimedes died c. 212 BC during the Second Punic War, when Roman forces under General Marcus Claudius Marcellus captured the city of Syracuse after a two-year-long siege. According to the popular account given by Plutarch, Archimedes was contemplating a mathematical diagram when the city was captured. A Roman soldier commanded him to come and meet General Marcellus but he declined, saying that he had to finish working on the problem. The soldier was enraged by this, and killed Archimedes with his sword. Plutarch also gives a lesser-known account of the death of Archimedes which suggests that he may have been killed while attempting to surrender to a Roman soldier. According to this story, Archimedes was carrying mathematical instruments, and was killed because the soldier thought that they were valuable items. General Marcellus was reportedly angered by the death of Archimedes, as he considered him a valuable scientific asset and had ordered that he must not be harmed.[18] Marcellus called Archimedes "a geometrical Briareus."[19]
+
+The last words attributed to Archimedes are "Do not disturb my circles", a reference to the circles in the mathematical drawing that he was supposedly studying when disturbed by the Roman soldier. This quote is often given in Latin as "Noli turbare circulos meos," but there is no reliable evidence that Archimedes uttered these words and they do not appear in the account given by Plutarch. Valerius Maximus, writing in Memorable Doings and Sayings in the 1st century AD, gives the phrase as "…sed protecto manibus puluere 'noli' inquit, 'obsecro, istum disturbare'" ("…but protecting the dust with his hands, said 'I beg of you, do not disturb this'"). The phrase is also given in Katharevousa Greek as "μὴ μου τοὺς κύκλους τάραττε!" (Mē mou tous kuklous taratte!).[18]
+
+The tomb of Archimedes carried a sculpture illustrating his favorite mathematical proof, consisting of a sphere and a cylinder of the same height and diameter. Archimedes had proven that the volume and surface area of the sphere are two thirds that of the cylinder including its bases. In 75 BC, 137 years after his death, the Roman orator Cicero was serving as quaestor in Sicily. He had heard stories about the tomb of Archimedes, but none of the locals were able to give him the location. Eventually he found the tomb near the Agrigentine gate in Syracuse, in a neglected condition and overgrown with bushes. Cicero had the tomb cleaned up, and was able to see the carving and read some of the verses that had been added as an inscription.[20] A tomb discovered in the courtyard of the Hotel Panorama in Syracuse in the early 1960s was claimed to be that of Archimedes, but there was no compelling evidence for this and the location of his tomb today is unknown.[21]
+
+The standard versions of the life of Archimedes were written long after his death by the historians of Ancient Rome. The account of the siege of Syracuse given by Polybius in his The Histories was written around seventy years after Archimedes' death, and was used subsequently as a source by Plutarch and Livy. It sheds little light on Archimedes as a person, and focuses on the war machines that he is said to have built in order to defend the city.[22]
+
+The most widely known anecdote about Archimedes tells of how he invented a method for determining the volume of an object with an irregular shape. According to Vitruvius, a votive crown for a temple had been made for King Hiero II of Syracuse, who had supplied the pure gold to be used, and Archimedes was asked to determine whether some silver had been substituted by the dishonest goldsmith.[23] Archimedes had to solve the problem without damaging the crown, so he could not melt it down into a regularly shaped body in order to calculate its density.
+
+While taking a bath, he noticed that the level of the water in the tub rose as he got in, and realized that this effect could be used to determine the volume of the crown. For practical purposes water is incompressible,[24] so the submerged crown would displace an amount of water equal to its own volume. By dividing the mass of the crown by the volume of water displaced, the density of the crown could be obtained. This density would be lower than that of gold if cheaper and less dense metals had been added. Archimedes then took to the streets naked, so excited by his discovery that he had forgotten to dress, crying "Eureka!" (Greek: "εὕρηκα, heúrēka!, lit. 'I have found [it]!').[23] The test was conducted successfully, proving that silver had indeed been mixed in.[25]
+
+The story of the golden crown does not appear in the known works of Archimedes. Moreover, the practicality of the method it describes has been called into question, due to the extreme accuracy with which one would have to measure the water displacement.[26] Archimedes may have instead sought a solution that applied the principle known in hydrostatics as Archimedes' principle, which he describes in his treatise On Floating Bodies. This principle states that a body immersed in a fluid experiences a buoyant force equal to the weight of the fluid it displaces.[27] Using this principle, it would have been possible to compare the density of the crown to that of pure gold by balancing the crown on a scale with a pure gold reference sample of the same weight, then immersing the apparatus in water. The difference in density between the two samples would cause the scale to tip accordingly. Galileo considered it "probable that this method is the same that Archimedes followed, since, besides being very accurate, it is based on demonstrations found by Archimedes himself."[28]
+
+In a 12th-century text titled Mappae clavicula there are instructions on how to perform the weighings in the water in order to calculate the percentage of silver used, and thus solve the problem.[29][30] The Latin poem Carmen de ponderibus et mensuris of the 4th or 5th century describes the use of a hydrostatic balance to solve the problem of the crown, and attributes the method to Archimedes.[29]
+
+A large part of Archimedes' work in engineering arose from fulfilling the needs of his home city of Syracuse. The Greek writer Athenaeus of Naucratis described how King Hiero II commissioned Archimedes to design a huge ship, the Syracusia, which could be used for luxury travel, carrying supplies, and as a naval warship. The Syracusia is said to have been the largest ship built in classical antiquity.[31] According to Athenaeus, it was capable of carrying 600 people and included garden decorations, a gymnasium and a temple dedicated to the goddess Aphrodite among its facilities. Since a ship of this size would leak a considerable amount of water through the hull, the Archimedes' screw was purportedly developed in order to remove the bilge water. Archimedes' machine was a device with a revolving screw-shaped blade inside a cylinder. It was turned by hand, and could also be used to transfer water from a low-lying body of water into irrigation canals. The Archimedes' screw is still in use today for pumping liquids and granulated solids such as coal and grain. The Archimedes' screw described in Roman times by Vitruvius may have been an improvement on a screw pump that was used to irrigate the Hanging Gardens of Babylon.[32][33] The world's first seagoing steamship with a screw propeller was the SS Archimedes, which was launched in 1839 and named in honor of Archimedes and his work on the screw.[34]
+
+The Claw of Archimedes is a weapon that he is said to have designed in order to defend the city of Syracuse. Also known as "the ship shaker," the claw consisted of a crane-like arm from which a large metal grappling hook was suspended. When the claw was dropped onto an attacking ship the arm would swing upwards, lifting the ship out of the water and possibly sinking it. There have been modern experiments to test the feasibility of the claw, and in 2005 a television documentary entitled Superweapons of the Ancient World built a version of the claw and concluded that it was a workable device.[35][36]
+
+Archimedes may have used mirrors acting collectively as a parabolic reflector to burn ships attacking Syracuse.
+The 2nd century AD author Lucian wrote that during the Siege of Syracuse (c. 214–212 BC), Archimedes destroyed enemy ships with fire. Centuries later, Anthemius of Tralles mentions burning-glasses as Archimedes' weapon.[37] The device, sometimes called the "Archimedes heat ray," was used to focus sunlight onto approaching ships, causing them to catch fire. In the modern era, similar devices have been constructed and may be referred to as a heliostat or solar furnace.[38]
+
+This purported weapon has been the subject of ongoing debate about its credibility since the Renaissance. René Descartes rejected it as false, while modern researchers have attempted to recreate the effect using only the means that would have been available to Archimedes.[39] It has been suggested that a large array of highly polished bronze or copper shields acting as mirrors could have been employed to focus sunlight onto a ship.
+
+A test of the Archimedes heat ray was carried out in 1973 by the Greek scientist Ioannis Sakkas. The experiment took place at the Skaramagas naval base outside Athens. On this occasion 70 mirrors were used, each with a copper coating and a size of around 5 by 3 feet (1.52 m × 0.91 m). The mirrors were pointed at a plywood mock-up of a Roman warship at a distance of around 160 feet (49 m). When the mirrors were focused accurately, the ship burst into flames within a few seconds. The plywood ship had a coating of tar paint, which may have aided combustion.[40] A coating of tar would have been commonplace on ships in the classical era.[b]
+
+In October 2005 a group of students from the Massachusetts Institute of Technology carried out an experiment with 127 one-foot (30 cm) square mirror tiles, focused on a mock-up wooden ship at a range of around 100 feet (30 m). Flames broke out on a patch of the ship, but only after the sky had been cloudless and the ship had remained stationary for around ten minutes. It was concluded that the device was a feasible weapon under these conditions. The MIT group repeated the experiment for the television show MythBusters, using a wooden fishing boat in San Francisco as the target. Again some charring occurred, along with a small amount of flame. In order to catch fire, wood needs to reach its autoignition temperature, which is around 300 °C (572 °F).[41][42]
+
+When MythBusters broadcast the result of the San Francisco experiment in January 2006, the claim was placed in the category of "busted" (i.e. failed) because of the length of time and the ideal weather conditions required for combustion to occur. It was also pointed out that since Syracuse faces the sea towards the east, the Roman fleet would have had to attack during the morning for optimal gathering of light by the mirrors. MythBusters also pointed out that conventional weaponry, such as flaming arrows or bolts from a catapult, would have been a far easier way of setting a ship on fire at short distances.[43]
+
+In December 2010, MythBusters again looked at the heat ray story in a special edition entitled "President's Challenge". Several experiments were carried out, including a large scale test with 500 schoolchildren aiming mirrors at a mock-up of a Roman sailing ship 400 feet (120 m) away. In all of the experiments, the sail failed to reach the 210 °C (410 °F) required to catch fire, and the verdict was again "busted". The show concluded that a more likely effect of the mirrors would have been blinding, dazzling, or distracting the crew of the ship.[44]
+
+While Archimedes did not invent the lever, he gave an explanation of the principle involved in his work On the Equilibrium of Planes. Earlier descriptions of the lever are found in the Peripatetic school of the followers of Aristotle, and are sometimes attributed to Archytas.[45][46] According to Pappus of Alexandria, Archimedes' work on levers caused him to remark: "Give me a place to stand on, and I will move the Earth" (Greek: δῶς μοι πᾶ στῶ καὶ τὰν γᾶν κινάσω).[47] Plutarch describes how Archimedes designed block-and-tackle pulley systems, allowing sailors to use the principle of leverage to lift objects that would otherwise have been too heavy to move.[48] Archimedes has also been credited with improving the power and accuracy of the catapult, and with inventing the odometer during the First Punic War. The odometer was described as a cart with a gear mechanism that dropped a ball into a container after each mile traveled.[49]
+
+Cicero (106–43 BC) mentions Archimedes briefly in his dialogue, De re publica, which portrays a fictional conversation taking place in 129 BC. After the capture of Syracuse c. 212 BC, General Marcus Claudius Marcellus is said to have taken back to Rome two mechanisms, constructed by Archimedes and used as aids in astronomy, which showed the motion of the Sun, Moon and five planets. Cicero mentions similar mechanisms designed by Thales of Miletus and Eudoxus of Cnidus. The dialogue says that Marcellus kept one of the devices as his only personal loot from Syracuse, and donated the other to the Temple of Virtue in Rome. Marcellus' mechanism was demonstrated, according to Cicero, by Gaius Sulpicius Gallus to Lucius Furius Philus, who described it thus:[50][51]
+
+Hanc sphaeram Gallus cum moveret, fiebat ut soli luna totidem conversionibus in aere illo quot diebus in ipso caelo succederet, ex quo et in caelo sphaera solis fieret eadem illa defectio, et incideret luna tum in eam metam quae esset umbra terrae, cum sol e regione.
+
+When Gallus moved the globe, it happened that the Moon followed the Sun by as many turns on that bronze contrivance as in the sky itself, from which also in the sky the Sun's globe became to have that same eclipse, and the Moon came then to that position which was its shadow on the Earth, when the Sun was in line.
+
+This is a description of a planetarium or orrery. Pappus of Alexandria stated that Archimedes had written a manuscript (now lost) on the construction of these mechanisms entitled On Sphere-Making. Modern research in this area has been focused on the Antikythera mechanism, another device built c. 100 BC that was probably designed for the same purpose.[52] Constructing mechanisms of this kind would have required a sophisticated knowledge of differential gearing.[53] This was once thought to have been beyond the range of the technology available in ancient times, but the discovery of the Antikythera mechanism in 1902 has confirmed that devices of this kind were known to the ancient Greeks.[54][55]
+
+While he is often regarded as a designer of mechanical devices, Archimedes also made contributions to the field of mathematics. Plutarch wrote: "He placed his whole affection and ambition in those purer speculations where there can be no reference to the vulgar needs of life."[56]
+
+Archimedes was able to use infinitesimals in a way that is similar to modern integral calculus. Through proof by contradiction (reductio ad absurdum), he could give answers to problems to an arbitrary degree of accuracy, while specifying the limits within which the answer lay. This technique is known as the method of exhaustion, and he employed it to approximate the value of π.
+
+In Measurement of a Circle, he did this by drawing a larger regular hexagon outside a circle then a smaller regular hexagon inside the circle, and progressively doubling the number of sides of each regular polygon, calculating the length of a side of each polygon at each step. As the number of sides increases, it becomes a more accurate approximation of a circle. After four such steps, when the polygons had 96 sides each, he was able to determine that the value of π lay between 31/7 (approx. 3.1429) and 310/71 (approx. 3.1408), consistent with its actual value of approximately 3.1416.[57]
+
+He also proved that the area of a circle was equal to π multiplied by the square of the radius of the circle (
+
+
+
+π
+
+r
+
+2
+
+
+
+
+{\textstyle \pi r^{2}}
+
+). In On the Sphere and Cylinder, Archimedes postulates that any magnitude when added to itself enough times will exceed any given magnitude. This is the Archimedean property of real numbers.[58]
+
+In Measurement of a Circle, Archimedes gives the value of the square root of 3 as lying between 265/153 (approximately 1.7320261) and 1351/780 (approximately 1.7320512). The actual value is approximately 1.7320508, making this a very accurate estimate. He introduced this result without offering any explanation of how he had obtained it. This aspect of the work of Archimedes caused John Wallis to remark that he was: "as it were of set purpose to have covered up the traces of his investigation as if he had grudged posterity the secret of his method of inquiry while he wished to extort from them assent to his results."[59] It is possible that he used an iterative procedure to calculate these values.[60]
+
+In The Quadrature of the Parabola, Archimedes proved that the area enclosed by a parabola and a straight line is 4/3 times the area of a corresponding inscribed triangle as shown in the figure at right. He expressed the solution to the problem as an infinite geometric series with the common ratio 1/4:
+
+If the first term in this series is the area of the triangle, then the second is the sum of the areas of two triangles whose bases are the two smaller secant lines, and so on. This proof uses a variation of the series 1/4 + 1/16 + 1/64 + 1/256 + · · · which sums to 1/3.
+
+In The Sand Reckoner, Archimedes set out to calculate the number of grains of sand that the universe could contain. In doing so, he challenged the notion that the number of grains of sand was too large to be counted. He wrote:
+
+There are some, King Gelo (Gelo II, son of Hiero II), who think that the number of the sand is infinite in multitude; and I mean by the sand not only that which exists about Syracuse and the rest of Sicily but also that which is found in every region whether inhabited or uninhabited.
+
+To solve the problem, Archimedes devised a system of counting based on the myriad. The word itself derives from the Greek μυριάς, murias, for the number 10,000. He proposed a number system using powers of a myriad of myriads (100 million, i.e., 10,000 x 10,000) and concluded that the number of grains of sand required to fill the universe would be 8 vigintillion, or 8×1063.[61]
+
+The works of Archimedes were written in Doric Greek, the dialect of ancient Syracuse.[62] The written work of Archimedes has not survived as well as that of Euclid, and seven of his treatises are known to have existed only through references made to them by other authors. Pappus of Alexandria mentions On Sphere-Making and another work on polyhedra, while Theon of Alexandria quotes a remark about refraction from the now-lost Catoptrica.[c] During his lifetime, Archimedes made his work known through correspondence with the mathematicians in Alexandria. The writings of Archimedes were first collected by the Byzantine Greek architect Isidore of Miletus (c. 530 AD), while commentaries on the works of Archimedes written by Eutocius in the sixth century AD helped to bring his work a wider audience. Archimedes' work was translated into Arabic by Thābit ibn Qurra (836–901 AD), and Latin by Gerard of Cremona (c. 1114–1187 AD). During the Renaissance, the Editio Princeps (First Edition) was published in Basel in 1544 by Johann Herwagen with the works of Archimedes in Greek and Latin.[63] Around the year 1586 Galileo Galilei invented a hydrostatic balance for weighing metals in air and water after apparently being inspired by the work of Archimedes.[64]
+
+There are two volumes to On the Equilibrium of Planes: the being is in fifteen propositions with seven postulates, while the second book is in ten propositions. In this work Archimedes explains the Law of the Lever, stating, "Magnitudes are in equilibrium at distances reciprocally proportional to their weights."
+
+Archimedes uses the principles derived to calculate the areas and centers of gravity of various geometric figures including triangles, parallelograms and parabolas.[65]
+
+This is a short work consisting of three propositions. It is written in the form of a correspondence with Dositheus of Pelusium, who was a student of Conon of Samos. In Proposition II, Archimedes gives an approximation of the value of pi (π), showing that it is greater than 223/71 and less than 22/7.
+
+This work of 28 propositions is also addressed to Dositheus. The treatise defines what is now called the Archimedean spiral. It is the locus of points corresponding to the locations over time of a point moving away from a fixed point with a constant speed along a line which rotates with constant angular velocity. Equivalently, in polar coordinates (r, θ) it can be described by the equation 
+
+
+
+
+r
+=
+a
++
+b
+θ
+
+
+{\displaystyle \,r=a+b\theta }
+
+  with real numbers a and b.
+
+This is an early example of a mechanical curve (a curve traced by a moving point) considered by a Greek mathematician.
+
+In this two-volume treatise addressed to Dositheus, Archimedes obtains the result of which he was most proud, namely the relationship between a sphere and a circumscribed cylinder of the same height and diameter. The volume is 4/3πr3 for the sphere, and 2πr3 for the cylinder. The surface area is 4πr2 for the sphere, and 6πr2 for the cylinder (including its two bases), where r is the radius of the sphere and cylinder. The sphere has a volume two-thirds that of the circumscribed cylinder. Similarly, the sphere has an area  two-thirds that of the cylinder (including the bases). A sculpted sphere and cylinder were placed on the tomb of Archimedes at his request.
+
+This is a work in 32 propositions addressed to Dositheus. In this treatise Archimedes calculates the areas and volumes of sections of cones, spheres, and paraboloids.
+
+In the first part of this two-volume treatise, Archimedes spells out the law of equilibrium of fluids, and proves that water will adopt a spherical form around a center of gravity. This may have been an attempt at explaining the theory of contemporary Greek astronomers such as Eratosthenes that the Earth is round. The fluids described by Archimedes are not self-gravitating, since he assumes the existence of a point towards which all things fall in order to derive the spherical shape.
+
+In the second part, he calculates the equilibrium positions of sections of paraboloids. This was probably an idealization of the shapes of ships' hulls. Some of his sections float with the base under water and the summit above water, similar to the way that icebergs float. Archimedes' principle of buoyancy is given in the work, stated as follows:
+
+Any body wholly or partially immersed in a fluid experiences an upthrust equal to, but opposite in sense to, the weight of the fluid displaced.
+
+In this work of 24 propositions addressed to Dositheus, Archimedes proves by two methods that the area enclosed by a parabola and a straight line is 4/3 multiplied by the area of a triangle with equal base and height. He achieves this by calculating the value of a geometric series that sums to infinity with the ratio 1/4.
+
+Also known as Loculus of Archimedes or Archimedes' Box,[66] this is a dissection puzzle similar to a Tangram, and the treatise describing it was found in more complete form in the Archimedes Palimpsest. Archimedes calculates the areas of the 14 pieces which can be assembled to form a square. Research published by Dr. Reviel Netz of Stanford University in 2003 argued that Archimedes was attempting to determine how many ways the pieces could be assembled into the shape of a square. Dr. Netz calculates that the pieces can be made into a square 17,152 ways.[67] The number of arrangements is 536 when solutions that are equivalent by rotation and reflection have been excluded.[68] The puzzle represents an example of an early problem in combinatorics.
+
+The origin of the puzzle's name is unclear, and it has been suggested that it is taken from the Ancient Greek word for 'throat' or 'gullet', stomachos (στόμαχος).[69] Ausonius refers to the puzzle as Ostomachion, a Greek compound word formed from the roots of osteon (ὀστέον, 'bone') and machē (μάχη, 'fight').[66]
+
+This work was discovered by Gotthold Ephraim Lessing in a Greek manuscript consisting of a poem of 44 lines, in the Herzog August Library in Wolfenbüttel, Germany in 1773. It is addressed to Eratosthenes and the mathematicians in Alexandria. Archimedes challenges them to count the numbers of cattle in the Herd of the Sun by solving a number of simultaneous Diophantine equations. There is a more difficult version of the problem in which some of the answers are required to be square numbers. This version of the problem was first solved by A. Amthor[70] in 1880, and the answer is a very large number, approximately 7.760271×10206544.[71]
+
+In this treatise, also known as Psammites, Archimedes counts the number of grains of sand that will fit inside the universe. This book mentions the heliocentric theory of the solar system proposed by Aristarchus of Samos, as well as contemporary ideas about the size of the Earth and the distance between various celestial bodies. By using a system of numbers based on powers of the myriad, Archimedes concludes that the number of grains of sand required to fill the universe is 8×1063 in modern notation. The introductory letter states that Archimedes' father was an astronomer named Phidias. The Sand Reckoner is the only surviving work in which Archimedes discusses his views on astronomy.[72]
+
+This treatise was thought lost until the discovery of the Archimedes Palimpsest in 1906. In this work Archimedes uses infinitesimals, and shows how breaking up a figure into an infinite number of infinitely small parts can be used to determine its area or volume. Archimedes may have considered this method lacking in formal rigor, so he also used the method of exhaustion to derive the results. As with The Cattle Problem, The Method of Mechanical Theorems was written in the form of a letter to Eratosthenes in Alexandria.
+
+Archimedes' Book of Lemmas or Liber Assumptorum is a treatise with fifteen propositions on the nature of circles. The earliest known copy of the text is in Arabic. The scholars T.L. Heath and Marshall Clagett argued that it cannot have been written by Archimedes in its current form, since it quotes Archimedes, suggesting modification by another author. The Lemmas may be based on an earlier work by Archimedes that is now lost.[73]
+
+It has also been claimed that Heron's formula for calculating the area of a triangle from the length of its sides was known to Archimedes.[d] However, the first reliable reference to the formula is given by Heron of Alexandria in the 1st century AD.[74]
+
+The foremost document containing the work of Archimedes is the Archimedes Palimpsest. In 1906, the Danish professor Johan Ludvig Heiberg visited Constantinople and examined a 174-page goatskin parchment of prayers written in the 13th century AD. He discovered that it was a palimpsest, a document with text that had been written over an erased older work. Palimpsests were created by scraping the ink from existing works and reusing them, which was a common practice in the Middle Ages as vellum was expensive. The older works in the palimpsest were identified by scholars as 10th century AD copies of previously unknown treatises by Archimedes.[75] The parchment spent hundreds of years in a monastery library in Constantinople before being sold to a private collector in the 1920s. On October 29, 1998 it was sold at auction to an anonymous buyer for $2 million at Christie's in New York.[76]
+
+The palimpsest holds seven treatises, including the only surviving copy of On Floating Bodies in the original Greek. It is the only known source of The Method of Mechanical Theorems, referred to by Suidas and thought to have been lost forever. Stomachion was also discovered in the palimpsest, with a more complete analysis of the puzzle than had been found in previous texts. The palimpsest is now stored at the Walters Art Museum in Baltimore, Maryland, where it has been subjected to a range of modern tests including the use of ultraviolet and x-ray light to read the overwritten text.[77]
+
+The treatises in the Archimedes Palimpsest include:
+

en/6011.html.txt

@@ -0,0 +1,77 @@
+
+
+Vitamin A is a group of unsaturated nutritional organic compounds that includes retinol, retinal, and several provitamin A carotenoids (most notably beta-carotene).[1][2] Vitamin A has multiple functions: it is important for growth and development, for the maintenance of the immune system, and for good vision.[3][4] Vitamin A is needed by the retina of the eye in the form of retinal, which combines with protein opsin to form rhodopsin, the light-absorbing molecule[5] necessary for both low-light (scotopic vision) and color vision.[6] Vitamin A also functions in a very different role as retinoic acid (an irreversibly oxidized form of retinol), which is an important hormone-like growth factor for epithelial and other cells.[4][7]
+
+In foods of animal origin, the major form of vitamin A is an ester, primarily retinyl palmitate, which is converted to retinol (chemically an alcohol) in the small intestine. The retinol form functions as a storage form of the vitamin, and can be converted to and from its visually active aldehyde form, retinal.
+
+All forms of vitamin A have a beta-ionone ring to which an isoprenoid chain is attached, called a retinyl group.[1] Both structural features are essential for vitamin activity.[8] The orange pigment of carrots (beta-carotene) can be represented as two connected retinyl groups, which are used in the body to contribute to vitamin A levels. Alpha-carotene and gamma-carotene also have a single retinyl group, which give them some vitamin activity. None of the other carotenes have vitamin activity. The carotenoid beta-cryptoxanthin possesses an ionone group and has vitamin activity in humans.
+
+Vitamin A can be found in two principal forms in foods:
+
+Vitamin A deficiency is estimated to affect approximately one third of children under the age of five around the world.[11] It is estimated to claim the lives of 670,000 children under five annually.[12] Between 250,000 and 500,000 children in developing countries become blind each year owing to vitamin A deficiency, with the highest prevalence in Africa and southeast Asia.[13] Vitamin A deficiency is "the leading cause of preventable childhood blindness", according to UNICEF.[14][15] It also increases the risk of death from common childhood conditions such as diarrhea. UNICEF regards addressing vitamin A deficiency as critical to reducing child mortality, the fourth of the United Nations' Millennium Development Goals.[14]
+
+Vitamin A deficiency can occur as either a primary or a secondary deficiency. A primary vitamin A deficiency occurs among children and adults who do not consume an adequate intake of provitamin A carotenoids from fruits and vegetables or preformed vitamin A from animal and dairy products. Early weaning from breastmilk can also increase the risk of vitamin A deficiency.
+
+Secondary vitamin A deficiency is associated with chronic malabsorption of lipids, impaired bile production and release, and chronic exposure to oxidants, such as cigarette smoke, and chronic alcoholism. Vitamin A is a fat-soluble vitamin and depends on micellar solubilization for dispersion into the small intestine, which results in poor use of vitamin A from low-fat diets. Zinc deficiency can also impair absorption, transport, and metabolism of vitamin A because it is essential for the synthesis of the vitamin A transport proteins and as the cofactor in conversion of retinol to retinal. In malnourished populations, common low intakes of vitamin A and zinc increase the severity of vitamin A deficiency and lead physiological signs and symptoms of deficiency.[16] A study in Burkina Faso showed major reduction of malaria morbidity by use of combined vitamin A and zinc supplementation in young children.[17]
+
+Due to the unique function of retinal as a visual chromophore, one of the earliest and specific manifestations of vitamin A deficiency is impaired vision, particularly in reduced light – night blindness. Persistent deficiency gives rise to a series of changes, the most devastating of which occur in the eyes. Some other ocular changes are referred to as xerophthalmia. First there is dryness of the conjunctiva (xerosis) as the normal lacrimal and mucus-secreting epithelium is replaced by a keratinized epithelium. This is followed by the build-up of keratin debris in small opaque plaques (Bitot's spots) and, eventually, erosion of the roughened corneal surface with softening and destruction of the cornea (keratomalacia) and leading to total blindness.[18] Other changes include impaired immunity (increased risk of ear infections, urinary tract infections, meningococcal disease), hyperkeratosis (white lumps at hair follicles), keratosis pilaris and squamous metaplasia of the epithelium lining the upper respiratory passages and urinary bladder to a keratinized epithelium. In relation to dentistry, a deficiency in vitamin A may lead to enamel hypoplasia.
+
+Adequate supply, but not excess vitamin A, is especially important for pregnant and breastfeeding women for normal fetal development and in breastmilk. Deficiencies cannot be compensated by postnatal supplementation.[19][20] Excess vitamin A, which is most common with high-dose vitamin supplements, can cause birth defects and therefore should not exceed recommended daily values.[21]
+
+Vitamin A metabolic inhibition as a result of alcohol consumption during pregnancy is one proposed mechanism for fetal alcohol syndrome, and is characterized by teratogenicity resembling maternal vitamin A deficiency or reduced retinoic acid synthesis during embryogenesis.[22][23][24]
+
+A 2012 review found no evidence that beta-carotene or vitamin A supplements increase longevity in healthy people or in people with various diseases.[26] A 2011 review found that vitamin A supplementation of children at risk of deficiency aged under five reduced mortality by up to 24%.[27] However, a 2016 and 2017 Cochrane review concluded there was not evidence to recommend blanket vitamin A supplementation for all infants less than a year of age, as it did not reduce infant mortality or morbidity in low- and middle-income countries.[28][29] The World Health Organization estimated that vitamin A supplementation averted 1.25 million deaths due to vitamin A deficiency in 40 countries since 1998.[30]
+
+While strategies include intake of vitamin A through a combination of breast feeding and dietary intake, delivery of oral high-dose supplements remain the principal strategy for minimizing deficiency.[31] About 75% of the vitamin A required for supplementation activity by developing countries is supplied by the Micronutrient Initiative with support from the Canadian International Development Agency.[32] Food fortification approaches are feasible,[33] but cannot ensure adequate intake levels.[31] Observational studies of pregnant women in sub-Saharan Africa have shown that low serum vitamin A levels are associated with an increased risk of mother-to-child transmission of HIV. Low blood vitamin A levels have been associated with rapid HIV infection and deaths.[34][35] Reviews on the possible mechanisms of HIV transmission found no relationship between blood vitamin A levels in the mother and infant, with conventional intervention established by treatment with anti-HIV drugs.[36][37]
+
+Given that vitamin A is fat-soluble, disposing of any excess taken in through diet takes much longer than with water-soluble B vitamins and vitamin C. This allows for toxic levels of vitamin A to accumulate. These toxicities only occur with preformed (retinoid) vitamin A (such as from liver). The carotenoid forms (for example, beta-carotene as found in carrots) give no such symptoms, but excessive dietary intake of beta-carotene can lead to carotenodermia, a harmless but cosmetically displeasing orange-yellow discoloration of the skin.[38][39][40]
+
+In general, acute toxicity occurs at doses of 25,000 IU/kg of body weight, with chronic toxicity occurring at 4,000 IU/kg of body weight daily for 6–15 months.[41] However, liver toxicities can occur at levels as low as 15,000 IU (4500 micrograms) per day to 1.4 million IU per day, with an average daily toxic dose of 120,000 IU, particularly with excessive consumption of alcohol.[citation needed] In people with kidney failure, 4000 IU can cause substantial damage. Signs of toxicity may occur with long-term consumption of vitamin A at doses of 25,000–33,000 IU per day.[1]
+
+Excessive vitamin A consumption can lead to nausea, irritability, anorexia (reduced appetite), vomiting, blurry vision, headaches, hair loss, muscle and abdominal pain and weakness, drowsiness, and altered mental status. In chronic cases, hair loss, dry skin, drying of the mucous membranes, fever, insomnia, fatigue, weight loss, bone fractures, anemia, and diarrhea can all be evident on top of the symptoms associated with less serious toxicity.[42] Some of these symptoms are also common to acne treatment with Isotretinoin. Chronically high doses of vitamin A, and also pharmaceutical retinoids such as 13-cis retinoic acid, can produce the syndrome of pseudotumor cerebri.[43] This syndrome includes headache, blurring of vision and confusion, associated with increased intracerebral pressure. Symptoms begin to resolve when intake of the offending substance is stopped.[44]
+
+Chronic intake of 1500 RAE of preformed vitamin A may be associated with osteoporosis and hip fractures because it suppresses bone building while simultaneously stimulating bone breakdown,[45] although other reviews have disputed this effect, indicating further evidence is needed.[1]
+
+A 2012 systematic review found that beta-carotene and higher doses of supplemental vitamin A increased mortality in healthy people and people with various diseases.[26] The findings of the review extend evidence that antioxidants may not have long-term benefits.
+
+As some carotenoids can be converted into vitamin A, attempts have been made to determine how much of them in the diet is equivalent to a particular amount of retinol, so that comparisons can be made of the benefit of different foods. The situation can be confusing because the accepted equivalences have changed. For many years, a system of equivalencies in which an international unit (IU) was equal to 0.3 μg of retinol, 0.6 μg of β-carotene, or 1.2 μg of other provitamin-A carotenoids was used.[46] Later, a unit called retinol equivalent (RE) was introduced. Prior to 2001, one RE corresponded to 1 μg retinol, 2 μg β-carotene dissolved in oil (it is only partly dissolved in most supplement pills, due to very poor solubility in any medium), 6 μg β-carotene in normal food (because it is not absorbed as well as when in oils), and 12 μg of either α-carotene, γ-carotene, or β-cryptoxanthin in food.
+
+Newer research has shown that the absorption of provitamin-A carotenoids is only half as much as previously thought. As a result, in 2001 the US Institute of Medicine recommended a new unit, the retinol activity equivalent (RAE). Each μg RAE corresponds to 1 μg retinol, 2 μg of β-carotene in oil, 12 μg of "dietary" beta-carotene, or 24 μg of the three other dietary provitamin-A carotenoids.[47]
+
+Because the conversion of retinol from provitamin carotenoids by the human body is actively regulated by the amount of retinol available to the body, the conversions apply strictly only for vitamin A-deficient humans.[citation needed] The absorption of provitamins depends greatly on the amount of lipids ingested with the provitamin; lipids increase the uptake of the provitamin.[48]
+
+A sample vegan diet for one day that provides sufficient vitamin A has been published by the Food and Nutrition Board (page 120[47]). Reference values for retinol or its equivalents, provided by the National Academy of Sciences, have decreased. The RDA (for men) established in 1968 was 5000 IU (1500 μg retinol). In 1974, the RDA was revised to 1000 RE (1000 μg retinol). As of 2001, the RDA for adult males is 900 RAE (900 μg or 3000 IU retinol).[citation needed] By RAE definitions, this is equivalent to 1800 μg of β-carotene supplement dissolved in oil (3000 IU) or 10800 μg of β-carotene in food (18000 IU).
+
+The U.S. Institute of Medicine (IOM) updated Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for vitamin A in 2001. For infants up to 12 months there was not sufficient information to establish a RDA, so Adequate Intake (AI) shown instead. As for safety the IOM sets tolerable upper intake levels (ULs) for vitamins and minerals when evidence is sufficient. Collectively the EARs, RDAs, AIs and ULs are referred to as Dietary Reference Intakes (DRIs). The calculation of retinol activity equivalents (RAE) is each μg RAE corresponds to 1 μg retinol, 2 μg of β-carotene in oil, 12 μg of "dietary" beta-carotene, or 24 μg of the three other dietary provitamin-A carotenoids.[47]
+
+For U.S. food and dietary supplement labeling purposes, the amount in a serving is expressed as a percent of Daily Value (%DV). For vitamin A labeling purposes 100% of the Daily Value was set at 5,000 IU, but it was revised to 900 μg RAE on 27 May 2016.[49][50] Compliance with the updated labeling regulations was required by 1 January 2020, for manufacturers with $10 million or more in annual food sales, and by 1 January 2021, for manufacturers with less than $10 million in annual food sales.[51][52][53] During the first six months following 1 January 2020 compliance date, the FDA plans to work cooperatively with manufacturers to meet the new Nutrition Facts label requirements and will not focus on enforcement actions regarding these requirements during that time.[51] A table of the old and new adult Daily Values is provided at Reference Daily Intake.
+
+The European Food Safety Authority (EFSA) refers to the collective set of information as Dietary Reference Values, with Population Reference Intake (PRI) instead of RDA, and Average Requirement instead of EAR. AI and UL defined the same as in United States. For women and men of ages 15 and older, the PRIs are set respectively at 650 and 750 μg/day. PRI for pregnancy is 700 μg/day, for lactation 1300/day. For children of ages 1–14 years, the PRIs increase with age from 250 to 600 μg/day. These PRIs are similar to the U.S. RDAs.[54] The EFSA reviewed the same safety question as the United States, and set a UL at 3000 μg/day.[55]
+
+Vitamin A is found in many foods, including the following list.[56] Bracketed values are retinol activity equivalences (RAEs) and percentage of the adult male RDA, per 100 grams of the foodstuff (average). Conversion of carotene to retinol varies from person to person, and bioavailability of carotene in food varies.[57][58]
+
+Vitamin A plays a role in a variety of functions throughout the body,[3] such as:
+
+The role of vitamin A in the visual cycle is specifically related to the retinal form. Within the eye, 11-cis-retinal is bound to the protein "opsin" to form rhodopsin in rods[5] and iodopsin (cones) at conserved lysine residues. As light enters the eye, the 11-cis-retinal is isomerized to the all-"trans" form. The all-"trans" retinal dissociates from the opsin in a series of steps called photo-bleaching. This isomerization induces a nervous signal along the optic nerve to the visual center of the brain. After separating from opsin, the all-"trans"-retinal is recycled and converted back to the 11-"cis"-retinal form by a series of enzymatic reactions. In addition, some of the all-"trans" retinal may be converted to all-"trans" retinol form and then transported with an interphotoreceptor retinol-binding protein (IRBP) to the pigment epithelial cells. Further esterification into all-"trans" retinyl esters allow for storage of all-trans-retinol within the pigment epithelial cells to be reused when needed.[16] The final stage is conversion of 11-cis-retinal will rebind to opsin to reform rhodopsin (visual purple) in the retina. Rhodopsin is needed to see in low light (contrast) as well as for night vision. Kühne showed that rhodopsin in the retina is only regenerated when the retina is attached to retinal pigmented epithelium,[5] which provides retinal. It is for this reason that a deficiency in vitamin A will inhibit the reformation of rhodopsin, and will lead to one of the first symptoms, night blindness.[59]
+
+Vitamin A, in the retinoic acid form, plays an important role in gene transcription. Once retinol has been taken up by a cell, it can be oxidized to retinal (retinaldehyde) by retinol dehydrogenases; retinaldehyde can then be oxidized to retinoic acid by retinaldehyde dehydrogenases.[21] The conversion of retinaldehyde to retinoic acid is an irreversible step; this means that the production of retinoic acid is tightly regulated, due to its activity as a ligand for nuclear receptors.[16] The physiological form of retinoic acid (all-trans-retinoic acid) regulates gene transcription by binding to nuclear receptors known as retinoic acid receptors (RARs) which are bound to DNA as heterodimers with retinoid "X" receptors (RXRs). RAR and RXR must dimerize before they can bind to the DNA. RAR will form a heterodimer with RXR (RAR-RXR), but it does not readily form a homodimer (RAR-RAR). RXR, on the other hand, may form a homodimer (RXR-RXR) and will form heterodimers with many other nuclear receptors as well, including the thyroid hormone receptor (RXR-TR), the Vitamin D3 receptor (RXR-VDR), the peroxisome proliferator-activated receptor (RXR-PPAR) and the liver "X" receptor (RXR-LXR).[60]
+
+The RAR-RXR heterodimer recognizes retinoic acid response elements (RAREs) on the DNA whereas the RXR-RXR homodimer recognizes retinoid "X" response elements (RXREs) on the DNA; although several RAREs near target genes have been shown to control physiological processes,[21] this has not been demonstrated for RXREs. The heterodimers of RXR with nuclear receptors other than RAR (i.e. TR, VDR, PPAR, LXR) bind to various distinct response elements on the DNA to control processes not regulated by vitamin A.[16] Upon binding of retinoic acid to the RAR component of the RAR-RXR heterodimer, the receptors undergo a conformational change that causes co-repressors to dissociate from the receptors. Coactivators can then bind to the receptor complex, which may help to loosen the chromatin structure from the histones or may interact with the transcriptional machinery.[60] This response can upregulate (or downregulate) the expression of target genes, including Hox genes as well as the genes that encode for the receptors themselves (i.e. RAR-beta in mammals).[16]
+
+Vitamin A plays a role in many areas of the immune system, particularly in T cell differentiation and proliferation.[61][62]
+
+Vitamin A promotes the proliferation of T cells through an indirect mechanism involving an increase in IL-2.[62] In addition to promoting proliferation, vitamin A (specifically retinoic acid) influences the differentiation of T cells.[63][64] In the presence of retinoic acid, dendritic cells located in the gut are able to mediate the differentiation of T cells into regulatory T cells.[64] Regulatory T cells are important for prevention of an immune response against "self" and regulating the strength of the immune response in order to prevent host damage.  Together with TGF-β, Vitamin A promotes the conversion of T cells to regulatory T cells.[63] Without Vitamin A, TGF-β stimulates differentiation into T cells that could create an autoimmune response.[63]
+
+Hematopoietic stem cells are important for the production of all blood cells, including immune cells, and are able to replenish these cells throughout the life of an individual. Dormant hematopoietic stem cells are able to self-renew, and are available to differentiate and produce new blood cells when they are needed. In addition to T cells, Vitamin A is important for the correct regulation of hematopoietic stem cell dormancy.[65] When cells are treated with all-trans retinoic acid, they are unable to leave the dormant state and become active, however, when vitamin A is removed from the diet, hematopoietic stem cells are no longer able to become dormant and the population of hematopoietic stem cells decreases.[65] This shows an importance in creating a balanced amount of vitamin A within the environment to allow these stem cells to transition between a dormant and activated state, in order to maintain a healthy immune system.
+
+Vitamin A has also been shown to be important for T cell homing to the intestine, effects dendritic cells, and can play a role in increased IgA secretion, which is important for the immune response in mucosal tissues.[61][66]
+
+Vitamin A, and more specifically, retinoic acid, appears to maintain normal skin health by switching on genes and differentiating keratinocytes (immature skin cells) into mature epidermal cells.[67] Exact mechanisms behind pharmacological retinoid therapy agents in the treatment of dermatological diseases are being researched. For the treatment of acne, the most prescribed retinoid drug is 13-cis retinoic acid (isotretinoin). It reduces the size and secretion of the sebaceous glands. Although it is known that 40 mg of isotretinoin will break down to an equivalent of 10 mg of ATRA — the mechanism of action of the drug (original brand name Accutane) remains unknown and is a matter of some controversy. Isotretinoin reduces bacterial numbers in both the ducts and skin surface. This is thought to be a result of the reduction in sebum, a nutrient source for the bacteria. Isotretinoin reduces inflammation via inhibition of chemotactic responses of monocytes and neutrophils.[16] Isotretinoin also has been shown to initiate remodeling of the sebaceous glands; triggering changes in gene expression that selectively induce apoptosis.[68] Isotretinoin is a teratogen with a number of potential side-effects. Consequently, its use requires medical supervision.
+
+Vitamin A-deprived rats can be kept in good general health with supplementation of retinoic acid. This reverses the growth-stunting effects of vitamin A deficiency, as well as early stages of xerophthalmia. However, such rats show infertility (in both male and females) and continued degeneration of the retina, showing that these functions require retinal or retinol, which are interconvertible but which cannot be recovered from the oxidized retinoic acid. The requirement of retinol to rescue reproduction in vitamin A deficient rats is now known to be due to a requirement for local synthesis of retinoic acid from retinol in testis and embryos.[69][70]
+
+Retinyl palmitate has been used in skin creams, where it is broken down to retinol and ostensibly metabolised to retinoic acid, which has potent biological activity, as described above. The retinoids (for example, 13-cis-retinoic acid) constitute a class of chemical compounds chemically related to retinoic acid, and are used in medicine to modulate gene functions in place of this compound. Like retinoic acid, the related compounds do not have full vitamin A activity, but do have powerful effects on gene expression and epithelial cell differentiation.[71] Pharmaceutics utilizing megadoses of naturally occurring retinoic acid derivatives are currently in use for cancer, HIV, and dermatological purposes.[72] At high doses, side-effects are similar to vitamin A toxicity.
+
+The discovery of vitamin A may have stemmed from research dating back to 1816, when physiologist François Magendie observed that dogs deprived of nutrition developed corneal ulcers and had a high mortality rate.[73] In 1912, Frederick Gowland Hopkins demonstrated that unknown accessory factors found in milk, other than carbohydrates, proteins, and fats were necessary for growth in rats. Hopkins received a Nobel Prize for this discovery in 1929.[73][74] By 1913, one of these substances was independently discovered by Elmer McCollum and Marguerite Davis at the University of Wisconsin–Madison, and Lafayette Mendel and Thomas Burr Osborne at Yale University, who studied the role of fats in the diet. McCollum and Davis ultimately received credit because they submitted their paper three weeks before Mendel and Osborne. Both papers appeared in the same issue of the Journal of Biological Chemistry in 1913.[75] The "accessory factors" were termed "fat soluble" in 1918 and later "vitamin A" in 1920. In 1919, Harry Steenbock (University of Wisconsin–Madison) proposed a relationship between yellow plant pigments (beta-carotene) and vitamin A. In 1931, Swiss chemist Paul Karrer described the chemical structure of vitamin A.[73] Vitamin A was first synthesized in 1947 by two Dutch chemists, David Adriaan van Dorp and Jozef Ferdinand Arens.
+
+During World War II, German bombers would attack at night to evade British defenses. In order to keep the 1939 invention of a new on-board Airborne Intercept Radar system secret from German bombers, the British Royal Ministry told newspapers that the nighttime defensive success of Royal Air Force pilots was due to a high dietary intake of carrots rich in vitamin A, propagating the myth that carrots enable people to see better in the dark.[76]

en/6012.html.txt

@@ -0,0 +1,160 @@
+
+
+Vitamin C, also known as ascorbic acid and ascorbate, is a vitamin found in various foods and sold as a dietary supplement.[4] It is used to prevent and treat scurvy.[4] Vitamin C is an essential nutrient involved in the repair of tissue and the enzymatic production of certain neurotransmitters.[4][5] It is required for the functioning of several enzymes and is important for immune system function.[5][6] It also functions as an antioxidant.[7]
+
+There is some evidence that regular use of supplements may reduce the duration of the common cold, but it does not appear to prevent infection.[7][8][9] It is unclear whether supplementation affects the risk of cancer, cardiovascular disease, or dementia.[10][11] It may be taken by mouth or by injection.[4]
+
+Vitamin C is generally well tolerated.[4] Large doses may cause gastrointestinal discomfort, headache, trouble sleeping, and flushing of the skin.[4][8] Normal doses are safe during pregnancy.[1] The United States Institute of Medicine recommends against taking large doses.[5]
+
+Vitamin C was discovered in 1912, isolated in 1928, and in 1933, was the first vitamin to be chemically produced.[12] It is on the World Health Organization's List of Essential Medicines, the safest and most effective medicines needed in a health system.[13] Vitamin C is available as an inexpensive generic and over-the-counter medication.[4][14][15] Partly for its discovery, Albert Szent-Györgyi and Walter Norman Haworth were awarded the 1937 Nobel Prizes in Physiology and Medicine and Chemistry, respectively.[16][17] Foods containing vitamin C include citrus fruits, kiwifruit, guava, broccoli, Brussels sprouts, bell peppers and strawberries.[7] Prolonged storage or cooking may reduce vitamin C content in foods.[7]
+
+Vitamin C is an essential nutrient for certain animals including humans. The term vitamin C encompasses several vitamers that have vitamin C activity in animals. Ascorbate salts such as sodium ascorbate and calcium ascorbate are used in some dietary supplements. These release ascorbate upon digestion. Ascorbate and ascorbic acid are both naturally present in the body, since the forms interconvert according to pH. Oxidized forms of the molecule such as dehydroascorbic acid are converted back to ascorbic acid by reducing agents.[5]
+
+Vitamin C functions as a cofactor in many enzymatic reactions in animals (and humans) that mediate a variety of essential biological functions, including wound healing and collagen synthesis. In humans, vitamin C deficiency leads to impaired collagen synthesis, contributing to the more severe symptoms of scurvy.[5] Another biochemical role of vitamin C is to act as an antioxidant (a reducing agent) by donating electrons to various enzymatic and non-enzymatic reactions.[5] Doing so converts vitamin C to an oxidized state - either as semidehydroascorbic acid or dehydroascorbic acid. These compounds can be restored to a reduced state by glutathione and NADPH-dependent enzymatic mechanisms.[18][19][20]
+
+In plants, vitamin C is a substrate for ascorbate peroxidase. This enzyme utilizes ascorbate to neutralize excess hydrogen peroxide (H2O2) by converting it to water (H2O) and oxygen.[6][21]
+
+Serum levels are considered saturated, achieved by consuming supplement amounts above the Recommended Dietary Allowance, at >65 μmol/L (1.1 mg/dL). Adequate defined as ≥50 μmol/L, hypovitaminosis at ≤23 μmol/L and deficient at ≤11.4 μmol/L.[22][23] For people ≥20 years old, data from the U.S. 2003-04 NHANES survey showed mean and median serum concentrations of 49.0 and 54.4 μmol/L, respectively. The percent of people reported as deficient was 7.1%.[23]
+
+Scurvy is a disease resulting from a deficiency of vitamin C. Without this vitamin, collagen made by the body is too unstable to perform its function and several other enzymes in the body do not operate correctly.[6] Scurvy is characterized by spots on and bleeding under the skin, spongy gums, 'corkscrew' hair growth, and poor wound healing. The skin lesions are most abundant on the thighs and legs, and a person with the ailment looks pale, feels depressed, and is partially immobilized. In advanced scurvy there are open, suppurating wounds, loss of teeth, bone abnormalities and, eventually, death.[24] The human body can store only a certain amount of vitamin C,[25] and so the body stores are depleted if fresh supplies are not consumed.
+
+Notable human dietary studies of experimentally induced scurvy were conducted on conscientious objectors during World War II in Britain and on Iowa state prisoners in the late 1960s to the 1980s. Men in the prison study developed the first signs of scurvy about four weeks after starting the vitamin C-free diet, whereas in the earlier British study, six to eight months were required, possibly due to the pre-loading of this group with a 70 mg/day supplement for six weeks before the scorbutic diet was fed. Men in both studies had blood levels of ascorbic acid too low to be accurately measured by the time they developed signs of scurvy. These studies both reported that all obvious symptoms of scurvy could be completely reversed by supplementation of only 10 mg a day.[26][27]
+
+Vitamin C has a definitive role in treating scurvy, which is a disease caused by vitamin C deficiency. Beyond that, a role for vitamin C as prevention or treatment for various diseases is disputed, with reviews reporting conflicting results. A 2012 Cochrane review reported no effect of vitamin C supplementation on overall mortality.[28] It is on the World Health Organization's List of Essential Medicines, the safest and most effective medicines needed in a health system.[13]
+
+The disease scurvy is caused by vitamin C deficiency and can be prevented and treated with vitamin C-containing foods or dietary supplements.[4][5] It takes at least a month of little to no vitamin C before symptoms occur.[26] Early symptoms are malaise and lethargy, progressing to shortness of breath, bone pain, bleeding gums, susceptibility to bruising, poor wound healing, and finally fever, convulsions and eventual death.[4] Until quite late in the disease the damage is reversible, as healthy collagen replaces the defective collagen with vitamin C repletion. Treatment can be orally or by intramuscular or intravenous injection.[4] Scurvy was known to Hippocrates in the classical era. The disease was shown to be prevented by citrus fruit in an early controlled trial by a Royal Navy surgeon, James Lind, in 1747, and from 1796 lemon juice was issued to all Royal Navy crewmen.[29][30]
+
+Research on vitamin C in the common cold has been divided into effects on prevention, duration, and severity. A Cochrane review which looked at at least 200 mg/day concluded that vitamin C taken on a regular basis was not effective in prevention of the common cold. Restricting analysis to trials that used at least 1000 mg/day also saw no prevention benefit. However, taking vitamin C on a regular basis did reduce the average duration by 8% in adults and 14% in children, and also reduced severity of colds.[9] A subsequent meta-analysis in children found that vitamin C approached statistical significance for prevention and reduced the duration of upper respiratory tract infections.[31] A subset of trials in adults reported that supplementation reduced the incidence of colds by half in marathon runners, skiers, or soldiers in subarctic conditions.[9] Another subset of trials looked at therapeutic use, meaning that vitamin C was not started unless the people started to feel the beginnings of a cold. In these, vitamin C did not impact duration or severity.[9] An earlier review stated that vitamin C did not prevent colds, did reduce duration, did not reduce severity.[32] The authors of the Cochrane review concluded that:
+
+The failure of vitamin C supplementation to reduce the incidence of colds in the general population indicates that routine vitamin C supplementation is not justified … Regular supplementation trials have shown that vitamin C reduces the duration of colds, but this was not replicated in the few therapeutic trials that have been carried out. Nevertheless, given the consistent effect of vitamin C on the duration and severity of colds in the regular supplementation studies, and the low cost and safety, it may be worthwhile for common cold patients to test on an individual basis whether therapeutic vitamin C is beneficial for them."[9]
+
+Vitamin C distributes readily in high concentrations into immune cells, has antimicrobial and natural killer cell activities, promotes lymphocyte proliferation, and is consumed quickly during infections, effects indicating a prominent role in immune system regulation.[33] The European Food Safety Authority found a cause and effect relationship exists between the dietary intake of vitamin C and functioning of a normal immune system in adults and in children under three years of age.[34][35]
+
+There are two approaches to the question of whether vitamin C has an impact on cancer. First, within the normal range of dietary intake without additional dietary supplementation, are people who consume more vitamin C at lower risk for developing cancer, and if so, does an orally consumed supplement have the same benefit? Second, for people diagnosed with cancer, will large amounts of ascorbic acid administered intravenously treat the cancer, reduce the adverse effects of other treatments, and so prolong survival and improve quality of life? A 2013 Cochrane review found no evidence that vitamin C supplementation reduces the risk of lung cancer in healthy people or those at high risk due to smoking or asbestos exposure.[36] A second meta-analysis found no effect on the risk of prostate cancer.[37] Two meta-analyses evaluated the effect of vitamin C supplementation on the risk of colorectal cancer. One found a weak association between vitamin C consumption and reduced risk, and the other found no effect from supplementation.[38][39] A 2011 meta-analysis failed to find support for the prevention of breast cancer with vitamin C supplementation,[40] but a second study concluded that vitamin C may be associated with increased survival in those already diagnosed.[41]
+
+Under the rubric of orthomolecular medicine, "Intravenous vitamin C is a contentious adjunctive cancer therapy, widely used in naturopathic and integrative oncology settings." [42] With oral administration absorption efficiency decreases as amounts increase. Intravenous administration bypasses this.[43] Doing so makes it possible to achieve plasma concentrations of 5 to 10 millimoles/liter (mmol/L), which far exceed the approximately 0.2 mmol/L limit from oral consumption.[44] The theories of mechanism are contradictory. At high tissue concentrations ascorbic acid is described as acting as a pro-oxidant, generating hydrogen peroxide (H2O2) to kill tumor cells. The same literature claims that ascorbic acid acts as an antioxidant, thereby reducing the adverse effects of chemotherapy and radiation therapy.[42][43] Research continues in this field, but a 2014 review concluded: "Currently, the use of high-dose intravenous vitamin C [as an anticancer agent] cannot be recommended outside of a clinical trial."[45] A 2015 review added: "There is no high-quality evidence to suggest that ascorbate supplementation in cancer patients either enhances the antitumor effects of chemotherapy or reduces its toxicity. Evidence for ascorbate's anti-tumor effects was limited to case reports and observational and uncontrolled studies."[46]
+
+There is no evidence as of 2017 that taking vitamin C decreases cardiovascular disease.[47] One 2013 review found no evidence that vitamin C supplementation reduces the risk of myocardial infarction, stroke, cardiovascular mortality, or all-cause mortality.[10] Another 2013 review found an association between higher circulating vitamin C levels or dietary vitamin C and a lower risk of stroke.[48]
+
+A 2014 review found a positive effect of vitamin C on endothelial function when taken at doses greater than 500 mg per day. The endothelium is a layer of cells that line the interior surface of blood vessels.[49]
+
+A 2017 systematic review found lower vitamin C concentrations in people with cognitive impairment, including Alzheimer's disease and dementia, compared to people with normal cognition.[50] The cognitive testing, however, relied on the Mini-Mental State Examination, which is only a general test of cognition, indicating an overall low quality of research assessing the potential importance of vitamin C on cognition in normal and impaired people.[50] A review of nutrient status in people with Alzheimer's disease reported low plasma vitamin C, but also low blood levels of folate, vitamin B12, and vitamin E.[51]
+
+Studies examining the effects of vitamin C intake on the risk of Alzheimer's disease have reached conflicting conclusions.[52][53] Maintaining a healthy dietary intake is probably more important than supplementation for achieving any potential benefit.[54] A 2010 review found no role for vitamin C supplementation in the treatment of rheumatoid arthritis.[55] Vitamin C supplementation does not prevent or slow the progression of age-related cataract.[56]
+
+Vitamin C is a water-soluble vitamin,[25] with dietary excesses not absorbed, and excesses in the blood rapidly excreted in the urine, so it exhibits remarkably low acute toxicity.[6] More than two to three grams may cause indigestion, particularly when taken on an empty stomach. However, taking vitamin C in the form of sodium ascorbate and calcium ascorbate may minimize this effect.[57] Other symptoms reported for large doses include nausea, abdominal cramps and diarrhea. These effects are attributed to the osmotic effect of unabsorbed vitamin C passing through the intestine.[5] In theory, high vitamin C intake may cause excessive absorption of iron. A summary of reviews of supplementation in healthy subjects did not report this problem, but left as untested the possibility that individuals with hereditary hemochromatosis might be adversely affected.[5]
+
+There is a longstanding belief among the mainstream medical community that vitamin C increases risk of kidney stones.[58] "Reports of kidney stone formation associated with excess ascorbic acid intake are limited to individuals with renal disease".[5] Reviews state that "data from epidemiological studies do not support an association between excess ascorbic acid intake and kidney stone formation in apparently healthy individuals",[5][59] although one large, multi-year trial did report a nearly two-fold increase in kidney stones in men who regularly consumed a vitamin C supplement.[60]
+
+Recommendations for vitamin C intake by adults have been set by various national agencies:
+
+In 2000 the North American Dietary Reference Intake chapter on vitamin C updated the Recommended Dietary Allowance (RDA) to 90 milligrams per day for adult men and 75 mg/day for adult women, and set a Tolerable upper intake level (UL) for adults of 2,000 mg/day.[5] The table shows RDAs for the United States and Canada for children, and for pregnant and lactating women.[5] For the European Union, the EFSA set higher recommendations for adults, and also for children: 20 mg/day for ages 1–3, 30 mg/day for ages 4–6, 45 mg/day for ages 7–10, 70 mg/day for ages 11–14, 100 mg/day for males ages 15–17, 90 mg/day for females ages 15–17. For pregnancy 100 mg/day; for lactation 155 mg/day.[66] India, on the other hand, has set recommendations much lower: 40 mg/day for ages 1 through adult, 60 mg/day for pregnancy, and 80 mg/day for lactation.[61] Clearly, there is not consensus among countries.
+
+Cigarette smokers and people exposed to secondhand smoke have lower serum vitamin C levels than nonsmokers.[23] The thinking is that inhalation of smoke causes oxidative damage, depleting this antioxidant vitamin.[5][65] The U.S. Institute of Medicine estimated that smokers need 35 mg more vitamin C per day than nonsmokers, but did not formally establish a higher RDA for smokers.[5] One meta-analysis showed an inverse relationship between vitamin C intake and lung cancer, although it concluded that more research is needed to confirm this observation.[67]
+
+The U.S. National Center for Health Statistics conducts biannual National Health and Nutrition Examination Survey (NHANES) to assess the health and nutritional status of adults and children in the United States. Some results are reported as What We Eat In America. The 2013-2014 survey reported that for adults ages 20 years and older, men consumed on average 83.3 mg/d and women 75.1 mg/d. This means that half the women and more than half the men are not consuming the RDA for vitamin C.[68] The same survey stated that about 30% of adults reported they consumed a vitamin C dietary supplement or a multi-vitamin/mineral supplement that included vitamin C, and that for these people total consumption was between 300 and 400 mg/d.[69]
+
+In 2000 the Institute of Medicine of the U.S. National Academy of Sciences set a Tolerable upper intake level (UL) for adults of 2,000 mg/day. The amount was chosen because human trials had reported diarrhea and other gastrointestinal disturbances at intakes of greater than 3,000 mg/day. This was the Lowest-Observed-Adverse-Effect Level (LOAEL), meaning that other adverse effects were observed at higher intakes.[5] The European Food Safety Authority (EFSA) reviewed the safety question in 2006 and reached the conclusion that there was not sufficient evidence to set a UL for vitamin C.[70] The Japan National Institute of Health and Nutrition reviewed the same question in 2010 and also reached the conclusion that there was not sufficient evidence to set a UL.[65]
+
+For U.S. food and dietary supplement labeling purposes, the amount in a serving is expressed as a percent of Daily Value (%DV). For vitamin C labeling purposes, 100% of the Daily Value was 60 mg, but as of May 27, 2016 it was revised to 90 mg to bring it into agreement with the RDA.[71][72] Compliance with the updated labeling regulations was required by 1 January 2020, for manufacturers with $10 million or more in annual food sales, and by 1 January 2021 for manufacturers with less than $10 million in annual food sales.[73][74][75] During the first six months following the 1 January 2020 compliance date, the FDA plans to work cooperatively with manufacturers to meet the new Nutrition Facts label requirements and will not focus on enforcement actions regarding these requirements during that time.[73] A table of the old and new adult Daily Values is provided at Reference Daily Intake.
+
+European Union regulations require that labels declare energy, protein, fat, saturated fat, carbohydrates, sugars, and salt. Voluntary nutrients may be shown if present in significant amounts. Instead of Daily Values, amounts are shown as percent of Reference Intakes (RIs). For vitamin C, 100% RI was set at 80 mg in 2011.[76]
+
+The richest natural sources of vitamin C are fruits and vegetables.[6] The vitamin is the most widely taken nutritional supplement and is available in a variety of forms,[6] including tablets, drink mixes, and in capsules.
+
+While plant foods are generally a good source of vitamin C, the amount in foods of plant origin depends on the variety of the plant, soil condition, climate where it grew, length of time since it was picked, storage conditions, and method of preparation.[77][78] The following table is approximate and shows the relative abundance in different raw plant sources.[79][80] As some plants were analyzed fresh while others were dried (thus, artificially increasing concentration of individual constituents like vitamin C), the data are subject to potential variation and difficulties for comparison. The amount is given in milligrams per 100 grams of the edible portion of the fruit or vegetable:
+
+Animal-sourced foods do not provide much vitamin C, and what there is, is largely destroyed by the heat of cooking. For example, raw chicken liver contains 17.9 mg/100 g, but fried, the content is reduced to 2.7 mg/100 g. Chicken eggs contain no vitamin C, raw or cooked.[81] Vitamin C is present in human breast milk at 5.0 mg/100 g and 6.1 mg/100 g in one tested sample of infant formula, but cow's milk contains only 1.0 mg/ 100 g.[87]
+
+Vitamin C chemically decomposes under certain conditions, many of which may occur during the cooking of food. Vitamin C concentrations in various food substances decrease with time in proportion to the temperature at which they are stored.[88] Cooking can reduce the vitamin C content of vegetables by around 60%, possibly due to increased enzymatic destruction.[89] Longer cooking times may add to this effect.[90]
+
+Another cause of vitamin C loss from food is leaching, which transfers vitamin C to the cooking water, which is decanted and not consumed. Broccoli may retain vitamin C during cooking or storage more than most vegetables.[91]
+
+Vitamin C dietary supplements are available as tablets, capsules, drink mix packets, in multi-vitamin/mineral formulations, in antioxidant formulations, and as crystalline powder.[4] Vitamin C is also added to some fruit juices and juice drinks. Tablet and capsule content ranges from 25 mg to 1500 mg per serving. The most commonly used supplement compounds are ascorbic acid, sodium ascorbate and calcium ascorbate.[4] Vitamin C molecules can also be bound to the fatty acid palmitate, creating ascorbyl palmitate, or else incorporated into liposomes.[92]
+
+In 2014, the Canadian Food Inspection Agency evaluated the effect of fortification of foods with ascorbate in the guidance document, Foods to Which Vitamins, Mineral Nutrients and Amino Acids May or Must be Added.[93] Voluntary and mandatory fortification was described for various classes of foods. Among foods classified for mandatory fortification with vitamin C were fruit-flavored drinks, mixes, and concentrates, foods for a low-energy diet, meal replacement products, and evaporated milk.[93]
+
+Ascorbic acid and some of its salts and esters are common additives added to various foods, such as canned fruits, mostly to retard oxidation and enzymatic browning.[94] The relevant European food additive E numbers are:
+
+Vitamin C – specifically, in the form of ascorbate – performs numerous physiological functions in the human body by serving as an enzyme substrate and/or cofactor and an electron donor. These functions include the synthesis of collagen, carnitine, and neurotransmitters; the synthesis and catabolism of tyrosine; and the metabolism of microsome.[20] During biosynthesis, ascorbate acts as a reducing agent, donating electrons and preventing oxidation to keep iron and copper atoms in their reduced states.
+
+Vitamin C functions as a cofactor for the following enzymes:
+
+From the U.S. National Institutes of Health: [In humans] "Approximately 70%–90% of vitamin C is absorbed at moderate intakes of 30–180 mg/day. However, at doses above 1,000 mg/day, absorption falls to less than 50%."[7] It is transported through the intestine via both glucose-sensitive and glucose-insensitive mechanisms, so the presence of large quantities of sugar in the intestine can slow absorption.[108]
+
+Ascorbic acid is absorbed in the body by both active transport and simple diffusion. Sodium-Dependent Active Transport—Sodium-Ascorbate Co-Transporters (SVCTs) and Hexose transporters (GLUTs)—are the two transporter proteins required for active absorption. SVCT1 and SVCT2 import the reduced form of ascorbate across plasma membranes.[109] GLUT1 and GLUT3 are glucose transporters, and transfer only the dehydroascorbic acid (DHA) form of vitamin C.[110] Although dehydroascorbic acid is absorbed in higher rate than ascorbate, the amount of dehydroascorbic acid found in plasma and tissues under normal conditions is low, as cells rapidly reduce dehydroascorbic acid to ascorbate.[111]
+
+SVCTs appear to be the predominant system for vitamin C transport in the body,[109] the notable exception being red blood cells, which lose SVCT proteins during maturation.[112] In both vitamin C synthesizers (example: rat) and non-synthesizers (example: human) cells with few exceptions maintain ascorbic acid concentrations much higher than the approximately 50 micromoles/liter (µmol/L) found in plasma. For example, the ascorbic acid content of pituitary and adrenal glands can exceed 2,000 µmol/L, and muscle is at 200-300 µmol/L.[113] The known coenzymatic functions of ascorbic acid do not require such high concentrations, so there may be other, as yet unknown functions. Consequences of all this organ content is that plasma vitamin C is not a good indicator of whole-body status, and people may vary in the amount of time needed to show symptoms of deficiency when consuming a diet very low in vitamin C.[113]
+
+Excretion can be as ascorbic acid, via urine. In humans, during times of low dietary intake, vitamin C is reabsorbed by the kidneys rather than excreted. Only when plasma concentrations are 1.4 mg/dL or higher does re-absorption decline and the excess amounts pass freely into the urine. This salvage process delays onset of deficiency.[114] Ascorbic acid also converts (reversibly) to dehydroascorbate (DHA) and from that compound non-reversibly to 2,3-diketogluonate and then oxalate. These three compounds are also excreted via urine. Humans are better than guinea pigs at converting DHA back to ascorbate, and thus take much longer to become vitamin C deficient.[115]
+
+
+
+The name "vitamin C" always refers to the l-enantiomer of ascorbic acid and its oxidized forms, such as dehydroascorbate (DHA). Therefore, unless written otherwise, "ascorbate" and "ascorbic acid" refer in the nutritional literature to l-ascorbate and l-ascorbic acid respectively. Ascorbic acid is a weak sugar acid structurally related to glucose. In biological systems, ascorbic acid can be found only at low pH, but in solutions above pH 5 is predominantly found in the ionized form, ascorbate. All of these molecules have vitamin C activity and thus are used synonymously with vitamin C, unless otherwise specified.
+
+Numerous analytical methods have been developed for ascorbic acid detection. For example, vitamin C content of a food sample such as fruit juice can be calculated by measuring the volume of the sample required to decolorize a solution of dichlorophenolindophenol (DCPIP) and then calibrating the results by comparison with a known concentration of vitamin C.[116][117]
+
+Simple tests are available to measure the levels of vitamin C in urine and serum.[22][23] These better reflect recent dietary intake rather than total body content.[5] It has been observed that while serum concentrations follow a circadian rhythm or reflect short-term dietary impact, content within cells or tissues is more stable and can give a better view of the availability of ascorbate within the entire organism. However, very few hospital laboratories are adequately equipped and trained to carry out such detailed analyses.[118][119]
+
+The vast majority of animals and plants are able to synthesize vitamin C, through a sequence of enzyme-driven steps, which convert monosaccharides to vitamin C. Yeasts do not make l-ascorbic acid but rather its stereoisomer, erythorbic acid.[120] In plants, this is accomplished through the conversion of mannose or galactose to ascorbic acid.[121][122] In animals, the starting material is glucose. In some species that synthesize ascorbate in the liver (including mammals and perching birds), the glucose is extracted from glycogen; ascorbate synthesis is a glycogenolysis-dependent process.[123] In humans and in animals that cannot synthesize vitamin C, the enzyme l-gulonolactone oxidase (GULO), that catalyses the last step in the biosynthesis, is highly mutated and non-functional.[124][125][126][127]
+
+There is some information on serum vitamin C concentrations maintained in animal species that are able to synthesize vitamin C. One study of several breeds of dogs reported an average of 35.9 μmol/L.[128] A report on goats, sheep and cattle reported ranges of 100-110, 265-270 and 160-350 μmol/L, respectively.[129]
+
+The biosynthesis of ascorbic acid in vertebrates starts with the formation of UDP-glucuronic acid. UDP-glucuronic acid is formed when UDP-glucose undergoes two oxidations catalyzed by the enzyme UDP-glucose 6-dehydrogenase. UDP-glucose 6-dehydrogenase uses the co-factor NAD+ as the electron acceptor. The transferase UDP-glucuronate pyrophosphorylase removes a UMP and glucuronokinase, with the cofactor ADP, removes the final phosphate leading to d-glucuronic acid. The aldehyde group of this compound is reduced to a primary alcohol using the enzyme glucuronate reductase and the cofactor NADPH, yielding l-gulonic acid. This is followed by lactone formation—utilizing the hydrolase gluconolactonase—between the carbonyl on C1 and hydroxyl group on C4. l-Gulonolactone then reacts with oxygen, catalyzed by the enzyme l-gulonolactone oxidase (which is nonfunctional in humans and other Haplorrhini primates; see Unitary pseudogenes) and the cofactor FAD+. This reaction produces 2-oxogulonolactone (2-keto-gulonolactone), which spontaneously undergoes enolization to form ascorbic acid.[130][131]
+[115]
+
+Some mammals have lost the ability to synthesize vitamin C, including simians and tarsiers, which together make up one of two major primate suborders, Haplorrhini. This group includes humans. The other more primitive primates (Strepsirrhini) have the ability to make vitamin C. Synthesis does not occur in most bats[124] nor in species in the rodent family Caviidae, that includes guinea pigs and capybaras, but does occur in other rodents, including rats and mice.[132]
+
+Reptiles and older orders of birds make ascorbic acid in their kidneys.  Recent orders of birds and most mammals make ascorbic acid in their liver.[122] A number of species of passerine birds also do not synthesize, but not all of them, and those that do not are not clearly related; there is a theory that the ability was lost separately a number of times in birds.[133] In particular, the ability to synthesize vitamin C is presumed to have been lost and then later re-acquired in at least two cases.[134] The ability to synthesize vitamin C has also been lost in about 96% of fish (the teleosts).[133]
+
+Most tested families of bats (order Chiroptera), including major insect and fruit-eating bat families, cannot synthesize vitamin C. A trace of gulonolactone oxidase was detected in only 1 of 34 bat species tested, across the range of 6 families of bats tested.[135] There are at least two species of bats, frugivorous bat (Rousettus leschenaultii) and insectivorous bat (Hipposideros armiger), that retain (or regained) their ability of vitamin C production.[136][137]
+
+Some of these species (including humans) are able to make do with the lower amounts available from their diets by recycling oxidised vitamin C.[138]
+
+On a milligram consumed per kilogram of body weight basis, most simian species consume the vitamin in amounts 10 to 20 times higher than what is recommended by governments for humans.[139] This discrepancy constitutes much of the basis of the controversy on current recommended dietary allowances. It is countered by arguments that humans are very good at conserving dietary vitamin C, and are able to maintain blood levels of vitamin C comparable with simians on a far smaller dietary intake, perhaps by recycling oxidized vitamin C.[138]
+
+There are many different biosynthesis pathways for ascorbic acid in plants. Most of these pathways are derived from products found in glycolysis and other pathways. For example, one pathway goes through the plant cell wall polymers.[124] The plant ascorbic acid biosynthesis pathway most principal seems to be l-galactose. l-Galactose reacts with the enzyme  l-galactose dehydrogenase, whereby the lactone ring opens and forms again but with lactone between the carbonyl on C1 and hydroxyl group on C4, resulting in l-galactonolactone.[131] l-Galactonolactone then reacts with the mitochondrial flavoenzyme l-galactonolactone dehydrogenase.[140] to produce ascorbic acid.[131] l-Ascorbic acid has a negative feedback on l-galactose dehydrogenase in spinach.[141]
+Ascorbic acid efflux by embryo of dicots plants is a well-established mechanism of iron reduction, and a step obligatory for iron uptake.[a]
+
+All plants synthesize ascorbic acid. Ascorbic acid functions as a cofactor for enzymes involved in photosynthesis, synthesis of plant hormones, as an antioxidant and also regenerator of other antioxidants.[143] Plants use multiple pathways to synthesize vitamin C. The major pathway starts with glucose, fructose or mannose (all simple sugars) and proceeds to L-galactose, L-galactonolactone and ascorbic acid.[143][144] There is feedback regulation in place, in that the presence of ascorbic acid inhibits enzymes in the synthesis pathway.[145] This process follows a diurnal rhythm, so that enzyme expression peaks in the morning to support biosynthesis later on when mid-day sunlight intensity demands high ascorbic acid concentrations.[144] Minor pathways may be specific to certain parts of plants; these can be either identical to the vertebrate pathway (including the GLO enzyme), or start with inositol and get to ascorbic acid via L-galactonic acid to L-galactonolactone.[143]
+
+Ascorbic acid is a common enzymatic cofactor in mammals used in the synthesis of collagen, as well as a powerful reducing agent capable of rapidly scavenging a number of reactive oxygen species (ROS). Given that ascorbate has these important functions, it is surprising that the ability to synthesize this molecule has not always been conserved. In fact, anthropoid primates, Cavia porcellus (guinea pigs), teleost fishes, most bats, and some Passeriform birds have all independently lost the ability to internally synthesize Vitamin C in either the kidney or the liver.[146][134] In all of the cases where genomic analysis was done on an ascorbic acid auxotroph, the origin of the change was found to be a result of loss-of-function mutations in the gene that codes for L-Gulono-γ-lactone oxidase, the enzyme that catalyzes the last step of the ascorbic acid pathway outlined above.[147] One explanation for the repeated loss of the ability to synthesize vitamin C is that it was the result of genetic drift; assuming that the diet was rich in vitamin C, natural selection would not act to preserve it.[148][149]
+
+In the case of the simians, it is thought that the loss of the ability to make vitamin C may have occurred much farther back in evolutionary history than the emergence of humans or even apes, since it evidently occurred soon after the appearance of the first primates, yet sometime after the split of early primates into the two major suborders Haplorrhini (which cannot make vitamin C) and its sister suborder of non-tarsier prosimians, the Strepsirrhini ("wet-nosed" primates), which retained the ability to make vitamin C.[150] According to molecular clock dating, these two suborder primate branches parted ways about 63 to 60 million years ago.[151] Approximately three to five million years later (58 million years ago), only a short time afterward from an evolutionary perspective, the infraorder Tarsiiformes, whose only remaining family is that of the tarsier (Tarsiidae), branched off from the other haplorrhines.[152][153] Since tarsiers also cannot make vitamin C, this implies the mutation had already occurred, and thus must have occurred between these two marker points (63 to 58 million years ago).[154]
+
+It has also been noted that the loss of the ability to synthesize ascorbate strikingly parallels the inability to break down uric acid, also a characteristic of primates. Uric acid and ascorbate are both strong reducing agents. This has led to the suggestion that, in higher primates, uric acid has taken over some of the functions of ascorbate.[155]
+
+Vitamin C is produced from glucose by two main routes. The Reichstein process, developed in the 1930s, uses a single pre-fermentation followed by a purely chemical route. The modern two-step fermentation process, originally developed in China in the 1960s, uses additional fermentation to replace part of the later chemical stages. The Reichstein process and the modern two-step fermentation processes use sorbitol as the starting material and convert it to sorbose using fermentation. The modern two-step fermentation process then converts sorbose to 2-keto-l-gulonic acid (KGA) through another fermentation step, avoiding an extra intermediate. 
+Both processes yield approximately 60% vitamin C from the glucose feed.[156]
+
+In 2017, China produced about 95% of the world supply of ascorbic acid (vitamin C),[157] which is China's most exported vitamin, having total revenue of US$880 million in 2017.[158] Due to pressure on Chinese industry to discontinue burning coal normally used for vitamin C manufacturing, the price of vitamin C rose three-fold in 2016 alone to US$12 per kg.[157]
+
+In the 1497 expedition of Vasco da Gama, the curative effects of citrus fruit were known.[159][160] Later, the Portuguese planted fruit trees and vegetables in Saint Helena, a stopping point for homebound voyages from Asia, which sustained passing ships.[161]
+
+Authorities occasionally recommended plant food to prevent scurvy during long sea voyages. John Woodall, the first surgeon to the British East India Company, recommended the preventive and curative use of lemon juice in his 1617 book, The Surgeon's Mate.[162] In 1734, the Dutch writer Johann Bachstrom gave the firm opinion that "scurvy is solely owing to a total abstinence from fresh vegetable food, and greens."[163][164]
+
+Scurvy had long been a principal killer of sailors during the long sea voyages.[165] According to Jonathan Lamb, "In 1499, Vasco da Gama lost 116 of his crew of 170; In 1520, Magellan lost 208 out of 230;...all mainly to scurvy."[166]
+
+The first attempt to give scientific basis for the cause of this disease was by a ship's surgeon in the Royal Navy, James Lind. While at sea in May 1747, Lind provided some crew members with two oranges and one lemon per day, in addition to normal rations, while others continued on cider, vinegar, sulfuric acid or seawater, along with their normal rations, in one of the world's first controlled experiments.[30] The results showed that citrus fruits prevented the disease. Lind published his work in 1753 in his Treatise on the Scurvy.[29][167]
+
+Fresh fruit was expensive to keep on board, whereas boiling it down to juice allowed easy storage but destroyed the vitamin (especially if boiled in copper kettles).[90] It was 1796 before the British navy adopted lemon juice as standard issue at sea. In 1845, ships in the West Indies were provided with lime juice instead, and in 1860 lime juice was used throughout the Royal Navy, giving rise to the American use of the nickname "limey" for the British.[30] Captain James Cook had previously demonstrated the advantages of carrying "Sour krout" on board, by taking his crews to the Hawaiian Islands without losing any of his men to scurvy.[168] For this, the British Admiralty awarded him a medal.
+
+The name antiscorbutic was used in the eighteenth and nineteenth centuries for foods known to prevent scurvy. These foods included lemons, limes, oranges, sauerkraut, cabbage, malt, and portable soup.[169] In 1928, the Canadian Arctic anthropologist Vilhjalmur Stefansson showed that the Inuit avoid scurvy on a diet of largely raw meat. Later studies on traditional food diets of the Yukon First Nations, Dene, Inuit, and Métis of Northern Canada showed that their daily intake of vitamin C averaged between 52 and 62 mg/day,[170] comparable with the Estimated Average Requirement.[5]
+
+Vitamin C was discovered in 1912, isolated in 1928 and synthesized in 1933, making it the first vitamin to be synthesized.[12] Shortly thereafter Tadeus Reichstein succeeded in synthesizing the vitamin in bulk by what is now called the Reichstein process.[172] This made possible the inexpensive mass-production of vitamin C. In 1934 Hoffmann–La Roche trademarked synthetic vitamin C under the brand name Redoxon[173] and began to market it as a dietary supplement.[b]
+
+In 1907 a laboratory animal model which would help to identify the antiscorbutic factor was discovered by the Norwegian physicians Axel Holst and Theodor Frølich, who when studying shipboard beriberi, fed guinea pigs their test diet of grains and flour and were surprised when scurvy resulted instead of beriberi. By luck, this species did not make its own vitamin C, whereas mice and rats do.[175] In 1912, the Polish biochemist Casimir Funk developed the concept of vitamins. One of these was thought to be the anti-scorbutic factor. In 1928, this was referred to as "water-soluble C," although its chemical structure had not been determined.[176]
+
+From 1928 to 1932, Albert Szent-Györgyi and Joseph L. Svirbely's Hungarian team, and Charles Glen King's American team, identified the anti-scorbutic factor. Szent-Györgyi isolated hexuronic acid from animal adrenal glands, and suspected it to be the antiscorbutic factor.[177] In late 1931, Szent-Györgyi gave Svirbely the last of his adrenal-derived hexuronic acid with the suggestion that it might be the anti-scorbutic factor. By the spring of 1932, King's laboratory had proven this, but published the result without giving Szent-Györgyi credit for it. This led to a bitter dispute over priority.[177] In 1933, Walter Norman Haworth chemically identified the vitamin as l-hexuronic acid, proving this by synthesis in 1933.[178][179][180][181] Haworth and Szent-Györgyi proposed that L-hexuronic acid be named a-scorbic acid, and chemically l-ascorbic acid, in honor of its activity against scurvy.[181][12] The term's etymology is from Latin, "a-" meaning away, or off from, while -scorbic is from Medieval Latin scorbuticus (pertaining to scurvy), cognate with Old Norse skyrbjugr, French scorbut, Dutch scheurbuik and Low German scharbock.[182] Partly for this discovery, Szent-Györgyi was awarded the 1937 Nobel Prize in Medicine,[183] and Haworth shared that year's Nobel Prize in Chemistry.[17]
+
+In 1957, J.J. Burns showed that some mammals are susceptible to scurvy as their liver does not produce the enzyme l-gulonolactone oxidase, the last of the chain of four enzymes that synthesize vitamin C.[184][185] American biochemist Irwin Stone was the first to exploit vitamin C for its food preservative properties. He later developed the theory that humans possess a mutated form of the l-gulonolactone oxidase coding gene.[186]
+
+In 2008, researchers at the University of Montpellier discovered that in humans and other primates the red blood cells have evolved a mechanism to more efficiently utilize the vitamin C present in the body by recycling oxidized l-dehydroascorbic acid (DHA) back into ascorbic acid for reuse by the body. The mechanism was not found to be present in mammals that synthesize their own vitamin C.[138]
+
+Vitamin C megadosage is a term describing the consumption or injection of vitamin C in doses comparable to or higher than the amounts produced by the livers of mammals which are able to synthesize vitamin C. The theory behind this, although not the actual term, was described in 1970 in an article by Linus Pauling. Briefly, his position was that for optimal health, humans should be consuming at least 2,300 mg/day to compensate for the inability to synthesize vitamin C. The recommendation also fell into the consumption range for gorillas - a non-synthesizing near-relative to humans.[187] A second argument for high intake is that serum ascorbic acid concentrations increase as intake increases until it plateaus at about 190 to 200 micromoles per liter (µmol/L) once consumption exceeds 1,250 milligrams.[188] As noted, government recommendations are a range of 40 to 110 mg/day and normal plasma is approximately 50 µmol/L, so 'normal' is about 25% of what can be achieved when oral consumption is in the proposed megadose range.
+
+Pauling popularized the concept of high dose vitamin C as prevention and treatment of the common cold in 1970. A few years later he proposed that vitamin C would prevent cardiovascular disease, and that 10 grams/day, initially (10 days) administered intravenously and thereafter orally, would cure late-stage cancer.[189] Mega-dosing with ascorbic acid has other champions, among them chemist Irwin Stone and the controversial Matthias Rath and Patrick Holford, who both have been accused of making unsubstantiated treatment claims for treating cancer and HIV infection.
+
+The mega-dosing theory is to a large degree discredited. Modest benefits are demonstrated for the common cold. Benefits are not superior when supplement intakes of more than 1,000 mg/day are compared to intakes between 200 and 1,000 mg/day, and so not limited to the mega-dose range.[190][191] The theory that large amounts of intravenous ascorbic acid can be used to treat late-stage cancer is - some forty years after Pauling's seminal paper - still considered unproven and still in need of high quality research.[45][46] However, a lack of conclusive evidence has not stopped individual physicians from prescribing intravenous ascorbic acid to thousands of people with cancer.[46]
+
+In February 2011, the Swiss Post issued a postage stamp bearing a depiction of a model of a molecule of vitamin C to mark the International Year of Chemistry.[192]

en/6013.html.txt

@@ -0,0 +1,90 @@
+
+
+
+
+A vitamin is an organic molecule (or a chemically closely related set of molecules, i.e. vitamers) that is an essential micronutrient which an organism needs in small quantities for the proper functioning of its metabolism. Essential nutrients cannot be synthesized in the organism, either at all or not in sufficient quantities, and therefore must be obtained through the diet. Vitamin C can be synthesized by some species but not by others; it is not a vitamin in the first instance but is in the second. The term vitamin does not include the three other groups of essential nutrients: minerals, essential fatty acids, and essential amino acids.[2] Most vitamins are not single molecules, but groups of related molecules called vitamers. For example, vitamin E consists of four tocopherols and four tocotrienols.  Some sources list fourteen vitamins, by including choline,[3]  but major health organizations list thirteen: vitamin A (as all-trans-retinol, all-trans-retinyl-esters, as well as all-trans-beta-carotene and other provitamin A carotenoids), vitamin B1 (thiamine), vitamin B2 (riboflavin), vitamin B3 (niacin), vitamin B5 (pantothenic acid), vitamin B6 (pyridoxine), vitamin B7 (biotin), vitamin B9 (folic acid or folate), vitamin B12 (cobalamins), vitamin C (ascorbic acid), vitamin D (calciferols), vitamin E (tocopherols and tocotrienols), and vitamin K (quinones).[4][5][6]
+
+Vitamins have diverse biochemical functions. Vitamin A acts as a regulator of cell and tissue growth and differentiation. Vitamin D provides a hormone-like function, regulating mineral metabolism for bones and other organs. The B complex vitamins function as enzyme cofactors (coenzymes) or the precursors for them. Vitamins C and E function as antioxidants.[7] Both deficient and excess intake of a vitamin can potentially cause clinically significant illness, although excess intake of water-soluble vitamins is less likely to do so.
+
+Before 1935, the only source of vitamins was from food[citation needed]. If intake of vitamins was lacking, the result was vitamin deficiency and consequent deficiency diseases. Then, commercially produced tablets of yeast-extract vitamin B complex and semi-synthetic vitamin C became available[citation needed]. This was followed in the 1950s by the mass production and marketing of vitamin supplements, including multivitamins, to prevent vitamin deficiencies in the general population. Governments mandated addition of vitamins to staple foods such as flour or milk, referred to as food fortification, to prevent deficiencies.[8] Recommendations for folic acid supplementation during pregnancy reduced risk of infant neural tube defects.[9]
+
+The term vitamin is derived from the word vitamine, which was coined in 1912 by Polish biochemist Casimir Funk, who isolated a complex of micronutrients essential to life, all of which he presumed to be amines.[10] When this presumption was later determined not to be true, the "e" was dropped from the name.[11]  All vitamins were discovered (identified) between 1913 and 1948[citation needed].
+
+from plant origin as provitamin A / all-trans-beta-carotene: orange, ripe yellow fruits, leafy vegetables, carrots, pumpkin, squash, spinach;
+
+Vitamins are classified as either water-soluble or fat-soluble. In humans there are 13 vitamins: 4 fat-soluble (A, D, E, and K) and 9 water-soluble (8 B vitamins and vitamin C). Water-soluble vitamins dissolve easily in water and, in general, are readily excreted from the body, to the degree that urinary output is a strong predictor of vitamin consumption.[24] Because they are not as readily stored, more consistent intake is important.[25] Fat-soluble vitamins are absorbed through the intestinal tract with the help of lipids (fats). Vitamins A and D can accumulate in the body, which can result in dangerous hypervitaminosis. Fat-soluble vitamin deficiency due to malabsorption is of particular significance in cystic fibrosis.[26]
+
+Anti-vitamins are chemical compounds that inhibit the absorption or actions of vitamins. For example, avidin is a protein in raw egg whites that inhibits the absorption of biotin; it is deactivated by cooking.[27] Pyrithiamine, a synthetic compound, has a molecular structure similar to thiamine, vitamin B1, and inhibits the enzymes that use thiamine.[28]
+
+Each vitamin is typically used in multiple reactions, and therefore most have multiple functions.[29]
+
+Vitamins are essential for the normal growth and development of a multicellular organism. Using the genetic blueprint inherited from its parents, a fetus develops from the nutrients it absorbs. It requires certain vitamins and minerals to be present at certain times.[9] These nutrients facilitate the chemical reactions that produce among other things, skin, bone, and muscle. If there is serious deficiency in one or more of these nutrients, a child may develop a deficiency disease. Even minor deficiencies may cause permanent damage.[30]
+
+Once growth and development are completed, vitamins remain essential nutrients for the healthy maintenance of the cells, tissues, and organs that make up a multicellular organism; they also enable a multicellular life form to efficiently use chemical energy provided by food it eats, and to help process the proteins, carbohydrates, and fats required for cellular respiration.[7]
+
+For the most part, vitamins are obtained from the diet, but some are acquired by other means: for example, microorganisms in the gut flora produce vitamin K and biotin; and one form of vitamin D is synthesized in skin cells when they are exposed to a certain wavelength of ultraviolet light present in sunlight. Humans can produce some vitamins from precursors they consume: for example, vitamin A is synthesized from beta carotene; and niacin is synthesized from the amino acid tryptophan.[31] The Food Fortification Initiative lists countries which have mandatory fortification programs for vitamins folic acid, niacin, vitamin A and vitamins B1, B2 and B12.[8]
+
+The body's stores for different vitamins vary widely; vitamins A, D, and B12 are stored in significant amounts, mainly in the liver,[20] and an adult's diet may be deficient in vitamins A and D for many months and B12 in some cases for years, before developing a deficiency condition. However, vitamin B3 (niacin and niacinamide) is not stored in significant amounts, so stores may last only a couple of weeks.[13][20] For vitamin C, the first symptoms of scurvy in experimental studies of complete vitamin C deprivation in humans have varied widely, from a month to more than six months, depending on previous dietary history that determined body stores.[32]
+
+Deficiencies of vitamins are classified as either primary or secondary. A primary deficiency occurs when an organism does not get enough of the vitamin in its food. A secondary deficiency may be due to an underlying disorder that prevents or limits the absorption or use of the vitamin, due to a "lifestyle factor", such as smoking, excessive alcohol consumption, or the use of medications that interfere with the absorption or use of the vitamin.[20] People who eat a varied diet are unlikely to develop a severe primary vitamin deficiency, but may be consuming less than the recommended amounts; a national food and supplement survey conducted in the US over 2003-2006 reported that over 90% of individuals who did not consume vitamin supplements were found to have inadequate levels of some of the essential vitamins, notably vitamins D and E.[33]
+
+Well-researched human vitamin deficiencies involve thiamine (beriberi), niacin (pellagra),[34] vitamin C (scurvy), folate (neural tube defects) and vitamin D (rickets).[35] In much of the developed world these deficiencies are rare due to an adequate supply of food and the  addition of vitamins to common foods.[20] In addition to these classical vitamin deficiency diseases, some evidence has also suggested links between vitamin deficiency and a number of different disorders.[36][37]
+
+Some vitamins have documented acute or chronic toxicity at larger intakes, which is referred to as hypertoxicity. The European Union and the governments of several countries have established Tolerable upper intake levels (ULs) for those vitamins which have documented toxicity (see table).[12][38][39] The likelihood of consuming too much of any vitamin from food is remote, but excessive intake (vitamin poisoning) from dietary supplements does occur. In 2016, overdose exposure to all formulations of vitamins and multi-vitamin/mineral formulations was reported by 63,931 individuals to the American Association of Poison Control Centers with 72% of these exposures in children under the age of five.[40] In the US, analysis of a national diet and supplement survey reported that about 7% of adult supplement users exceeded the UL for folate and 5% of those older than age 50 years exceeded the UL for vitamin A.[33]
+
+The USDA has conducted extensive studies on the percentage losses of various nutrients from food types and cooking methods.[41] Some vitamins may become more "bio-available" – that is, usable by the body – when foods are cooked.[42] The table below shows whether various vitamins are susceptible to loss from heat—such as heat from boiling, steaming, frying, etc. The effect of cutting vegetables can be seen from exposure to air and light. Water-soluble vitamins such as B and C dissolve into the water when a vegetable is boiled, and are then lost when the water is discarded.[43]
+
+In setting human nutrient guidelines, government organizations do not necessarily agree on amounts needed to avoid deficiency or maximum amounts to avoid the risk of toxicity.[38][12][39] For example, for vitamin C, recommended intakes range from 40 mg/day in India[44] to 155 mg/day for the European Union.[45] The table below shows U.S. Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for vitamins, PRIs for the European Union (same concept as RDAs), followed by what three government organizations deem to be the safe upper intake. RDAs are set higher than EARs to cover people with higher than average needs. Adequate Intakes (AIs) are set when there is not sufficient information to establish EARs and RDAs. Governments are slow to revise information of this nature. For the U.S. values, with the exception of calcium and vitamin D, all of the data date to 1997-2004.[46]
+
+EAR US Estimated Average Requirements.
+
+RDA US Recommended Dietary Allowances; higher for adults than for children, and may be even higher for women who are pregnant or lactating.
+
+AI  US and EFSA Adequate Intake; AIs established when there is not sufficient information to set EARs and RDAs.
+
+PRI Population Reference Intake is European Union equivalent of RDA; higher for adults than for children, and may be even higher for women who are pregnant or lactating. For Thiamin and Niacin the PRIs are expressed as amounts per MJ of calories consumed. MJ = megajoule = 239 food calories.
+
+UL or Upper Limit  Tolerable upper intake levels.
+
+ND  ULs have not been determined.
+
+NE  EARs have not been established.
+
+In those who are otherwise healthy, there is little evidence that supplements have any benefits with respect to cancer or heart disease.[47][48][49] Vitamin A and E supplements not only provide no health benefits for generally healthy individuals, but they may increase mortality, though the two large studies that support this conclusion included smokers for whom it was already known that beta-carotene supplements can be harmful.[48][50] A 2018 meta-analysis found no evidence that intake of vitamin D or calcium for community-dwelling elderly people reduced bone fractures.[51]
+
+Europe has regulations that define limits of vitamin (and mineral) dosages for their safe use as dietary supplements. Most vitamins that are sold as dietary supplements are not supposed to exceed a maximum daily dosage referred to as the tolerable upper intake level (UL or Upper Limit). Vitamin products above these regulatory limits are not considered supplements and should be registered as prescription or non-prescription (over-the-counter drugs) due to their potential side effects. The European Union, United States and Japan establish ULs.[12][38][39]
+
+Dietary supplements often contain vitamins, but may also include other ingredients, such as minerals, herbs, and botanicals. Scientific evidence supports the benefits of dietary supplements for persons with certain health conditions.[52] In some cases, vitamin supplements may have unwanted effects, especially if taken before surgery, with other dietary supplements or medicines, or if the person taking them has certain health conditions.[52] They may also contain levels of vitamins many times higher, and in different forms, than one may ingest through food.
+
+Most countries place dietary supplements in a special category under the general umbrella of foods, not drugs. As a result, the manufacturer, and not the government, has the responsibility of ensuring that its dietary supplement products are safe before they are marketed. Regulation of supplements varies widely by country. In the United States, a dietary supplement is defined under the Dietary Supplement Health and Education Act of 1994.[53] There is no FDA approval process for dietary supplements, and no requirement that manufacturers prove the safety or efficacy of supplements introduced before 1994.[34][35] The Food and Drug Administration must rely on its Adverse Event Reporting System to monitor adverse events that occur with supplements.[54] In 2007, the US Code of Federal Regulations (CFR) Title 21, part III took effect, regulating Good Manufacturing Practices (GMPs) in the manufacturing, packaging, labeling, or holding operations for dietary supplements. Even though product registration is not required, these regulations mandate production and quality control standards (including testing for identity, purity and adulterations) for dietary supplements.[55] In the European Union, the Food Supplements Directive requires that only those supplements that have been proven safe can be sold without a prescription.[56]
+For most vitamins, pharmacopoeial standards have been established. In the United States, the United States Pharmacopeia (USP) sets standards for the most commonly used vitamins and preparations thereof. Likewise, monographs of the European Pharmacopoeia (Ph.Eur.) regulate aspects of identity and purity for vitamins on the European market.
+
+The reason that the set of vitamins skips directly from E to K is that the vitamins corresponding to letters F–J were either reclassified over time, discarded as false leads, or renamed because of their relationship to vitamin B, which became a complex of vitamins.
+
+The German-speaking scientists who isolated and described vitamin K (in addition to naming it as such) did so because the vitamin is intimately involved in the coagulation of blood following wounding (from the German word Koagulation). At the time, most (but not all) of the letters from F through to J were already designated, so the use of the letter K was considered quite reasonable.[57][60] The table Nomenclature of reclassified vitamins lists chemicals that had previously been classified as vitamins, as well as the earlier names of vitamins that later became part of the B-complex.
+
+The missing B vitamins were reclassified or determined not to be vitamins. For example, B9 is folic acid and five of the folates are in the range B11 through B16.  Others, such as PABA (formerly B10), are biologically inactive, toxic, or with unclassifiable effects in humans, or not generally recognised as vitamins by science,[61] such as the highest-numbered, which some naturopath practitioners call B21 and B22. There are also nine lettered B complex vitamins (e.g., Bm). There are other D vitamins now recognised as other substances, which some sources of the same type number up to D7. The controversial cancer treatment laetrile was at one point lettered as vitamin B17. There appears to be no consensus on any vitamins Q, R, T, V, W, X, Y or Z, nor are there substances officially designated as vitamins N or I, although the latter may have been another form of one of the other vitamins or a known and named nutrient of another type.
+
+The value of eating certain foods to maintain health was recognized long before vitamins were identified. The ancient Egyptians knew that feeding liver to a person may help with night blindness, an illness now known to be caused by a vitamin A deficiency.[62] The advancement of ocean voyages during the Renaissance resulted in prolonged periods without access to fresh fruits and vegetables, and made illnesses from vitamin deficiency common among ships' crews.[63]
+
+In 1747, the Scottish surgeon James Lind discovered that citrus foods helped prevent scurvy, a particularly deadly disease in which collagen is not properly formed, causing poor wound healing, bleeding of the gums, severe pain, and death.[62] In 1753, Lind published his Treatise on the Scurvy, which recommended using lemons and limes to avoid scurvy, which was adopted by the British Royal Navy. This led to the nickname limey for British sailors. Lind's discovery, however, was not widely accepted by individuals in the Royal Navy's Arctic expeditions in the 19th century, where it was widely believed that scurvy could be prevented by practicing good hygiene, regular exercise, and maintaining the morale of the crew while on board, rather than by a diet of fresh food.[62] As a result, Arctic expeditions continued to be plagued by scurvy and other deficiency diseases. In the early 20th century, when Robert Falcon Scott made his two expeditions to the Antarctic, the prevailing medical theory at the time was that scurvy was caused by "tainted" canned food.[62]
+
+During the late 18th and early 19th centuries, the use of deprivation studies allowed scientists to isolate and identify a number of vitamins. Lipid from fish oil was used to cure rickets in rats, and the fat-soluble nutrient was called "antirachitic A". Thus, the first "vitamin" bioactivity ever isolated, which cured rickets, was initially called "vitamin A"; however, the bioactivity of this compound is now called vitamin D.[65] In 1881, Russian medical doctor Nikolai I. Lunin [ru] studied the effects of scurvy at the University of Tartu. He fed mice an artificial mixture of all the separate constituents of milk known at that time, namely the proteins, fats, carbohydrates, and salts. The mice that received only the individual constituents died, while the mice fed by milk itself developed normally. He made a conclusion that "a natural food such as milk must therefore contain, besides these known principal ingredients, small quantities of unknown substances essential to life." However, his conclusions were rejected by his advisor, Gustav von Bunge.[66] A similar result by Cornelius Pekelharing appeared in a Dutch medical journal in 1905, but it was not widely reported.[66]
+
+In East Asia, where polished white rice was the common staple food of the middle class, beriberi resulting from lack of vitamin B1 was endemic. In 1884, Takaki Kanehiro, a British-trained medical doctor of the Imperial Japanese Navy, observed that beriberi was endemic among low-ranking crew who often ate nothing but rice, but not among officers who consumed a Western-style diet. With the support of the Japanese navy, he experimented using crews of two battleships; one crew was fed only white rice, while the other was fed a diet of meat, fish, barley, rice, and beans. The group that ate only white rice documented 161 crew members with beriberi and 25 deaths, while the latter group had only 14 cases of beriberi and no deaths. This convinced Takaki and the Japanese Navy that diet was the cause of beriberi, but they mistakenly believed that sufficient amounts of protein prevented it.[67] That diseases could result from some dietary deficiencies was further investigated by Christiaan Eijkman, who in 1897 discovered that feeding unpolished rice instead of the polished variety to chickens helped to prevent a kind of polyneuritis that was the equivalent of beriberi.[34] The following year, Frederick Hopkins postulated that some foods contained "accessory factors" — in addition to proteins, carbohydrates, fats etc. — that are necessary for the functions of the human body.[62] Hopkins and Eijkman were awarded the Nobel Prize for Physiology or Medicine in 1929 for their discoveries.[68]
+
+In 1910, the first vitamin complex was isolated by Japanese scientist Umetaro Suzuki, who succeeded in extracting a water-soluble complex of micronutrients from rice bran and named it aberic acid (later Orizanin). He published this discovery in a Japanese scientific journal.[69] When the article was translated into German, the translation failed to state that it was a newly discovered nutrient, a claim made in the original Japanese article, and hence his discovery failed to gain publicity. In 1912 Polish-born biochemist Casimir Funk, working in London, isolated the same complex of micronutrients and proposed the complex be named "vitamine".[10] It was later to be known as vitamin B3 (niacin), though he described it as "anti-beri-beri-factor" (which would today be called thiamine or vitamin B1). Funk proposed the hypothesis that other diseases, such as rickets, pellagra, coeliac disease, and scurvy could also be cured by vitamins. Max Nierenstein a friend and reader of Biochemistry at Bristol University reportedly suggested the "vitamine" name (from "vital amine").[70][71] The name soon became synonymous with Hopkins' "accessory factors", and, by the time it was shown that not all vitamins are amines, the word was already ubiquitous. In 1920, Jack Cecil Drummond proposed that the final "e" be dropped to deemphasize the "amine" reference, hence "vitamin," after researchers began to suspect that not all "vitamines" (in particular, vitamin A) have an amine component.[67]
+
+The Nobel Prize in Physiology or Medicine for 1929 was awarded to Christiaan Eijkman and Sir Frederick Gowland Hopkins for their contributions to the discovery of vitamins.[72] Thirty-five years earlier, Eijkman had observed that chickens fed polished white rice developed neurological symptoms similar to those observed in military sailors and soldiers fed a rice-based diet, and that the symptoms were reversed when the chickens were switched to whole-grain rice. He called this "the anti-beriberi factor", which was later identified as vitamin B1, thiamine.[73]
+
+In 1930, Paul Karrer elucidated the correct structure for beta-carotene, the main precursor of vitamin A, and identified other carotenoids. Karrer and Norman Haworth confirmed Albert Szent-Györgyi's discovery of ascorbic acid and made significant contributions to the chemistry of flavins, which led to the identification of lactoflavin. For their investigations on carotenoids, flavins and vitamins A and B2, they both received the Nobel Prize in Chemistry in 1937.[74]
+
+In 1931, Albert Szent-Györgyi and a fellow researcher Joseph Svirbely suspected that "hexuronic acid" was actually vitamin C, and gave a sample to Charles Glen King, who proved its anti-scorbutic activity in his long-established guinea pig scorbutic assay. In 1937, Szent-Györgyi was awarded the Nobel Prize in Physiology or Medicine for his discovery. In 1943, Edward Adelbert Doisy and Henrik Dam were awarded the Nobel Prize in Physiology or Medicine for their discovery of vitamin K and its chemical structure. In 1967, George Wald was awarded the Nobel Prize (along with Ragnar Granit and Haldan Keffer Hartline) for his discovery that vitamin A could participate directly in a physiological process.[68]
+
+In 1938, Richard Kuhn was awarded the Nobel Prize in Chemistry for his work on carotenoids and vitamins, specifically B2 and B6.[75]
+
+Five people have been awarded Nobel Prizes for direct and indirect studies of vitamin B12: George Whipple, George Minot and William P. Murphy (1934), Alexander R. Todd (1957), and Dorothy Hodgkin (1964).[72]
+
+Once discovered, vitamins were actively promoted in articles and advertisements in McCall's, Good Housekeeping, and other media outlets.[34] Marketers enthusiastically promoted cod-liver oil, a source of Vitamin D, as "bottled sunshine", and bananas as a “natural vitality food". They promoted foods such as yeast cakes, a source of B vitamins, on the basis of scientifically-determined nutritional value, rather than taste or appearance.[76] World War II researchers focused on the need to ensure adequate nutrition, especially in processed foods.[34] Robert W. Yoder is credited with first using the term vitamania, in 1942, to describe the appeal of relying on nutritional supplements rather than on obtaining vitamins from a varied diet of foods. The continuing preoccupation with a healthy lifestyle has led to an obsessive consumption of additives the beneficial effects of which are questionable.[35]
+
+The term vitamin was derived from "vitamine", a compound word coined in 1912 by the Polish biochemist Casimir Funk[10][77] when working at the Lister Institute of Preventive Medicine. The name is from vital and amine, meaning amine of life, because it was suggested in 1912 that the organic micronutrient food factors that prevent beriberi and perhaps other similar dietary-deficiency diseases might be chemical amines. This was true of thiamine, but after it was found that other such micronutrients were not amines the word was shortened to vitamin in English.

en/6014.html.txt

@@ -0,0 +1,90 @@
+
+
+
+
+A vitamin is an organic molecule (or a chemically closely related set of molecules, i.e. vitamers) that is an essential micronutrient which an organism needs in small quantities for the proper functioning of its metabolism. Essential nutrients cannot be synthesized in the organism, either at all or not in sufficient quantities, and therefore must be obtained through the diet. Vitamin C can be synthesized by some species but not by others; it is not a vitamin in the first instance but is in the second. The term vitamin does not include the three other groups of essential nutrients: minerals, essential fatty acids, and essential amino acids.[2] Most vitamins are not single molecules, but groups of related molecules called vitamers. For example, vitamin E consists of four tocopherols and four tocotrienols.  Some sources list fourteen vitamins, by including choline,[3]  but major health organizations list thirteen: vitamin A (as all-trans-retinol, all-trans-retinyl-esters, as well as all-trans-beta-carotene and other provitamin A carotenoids), vitamin B1 (thiamine), vitamin B2 (riboflavin), vitamin B3 (niacin), vitamin B5 (pantothenic acid), vitamin B6 (pyridoxine), vitamin B7 (biotin), vitamin B9 (folic acid or folate), vitamin B12 (cobalamins), vitamin C (ascorbic acid), vitamin D (calciferols), vitamin E (tocopherols and tocotrienols), and vitamin K (quinones).[4][5][6]
+
+Vitamins have diverse biochemical functions. Vitamin A acts as a regulator of cell and tissue growth and differentiation. Vitamin D provides a hormone-like function, regulating mineral metabolism for bones and other organs. The B complex vitamins function as enzyme cofactors (coenzymes) or the precursors for them. Vitamins C and E function as antioxidants.[7] Both deficient and excess intake of a vitamin can potentially cause clinically significant illness, although excess intake of water-soluble vitamins is less likely to do so.
+
+Before 1935, the only source of vitamins was from food[citation needed]. If intake of vitamins was lacking, the result was vitamin deficiency and consequent deficiency diseases. Then, commercially produced tablets of yeast-extract vitamin B complex and semi-synthetic vitamin C became available[citation needed]. This was followed in the 1950s by the mass production and marketing of vitamin supplements, including multivitamins, to prevent vitamin deficiencies in the general population. Governments mandated addition of vitamins to staple foods such as flour or milk, referred to as food fortification, to prevent deficiencies.[8] Recommendations for folic acid supplementation during pregnancy reduced risk of infant neural tube defects.[9]
+
+The term vitamin is derived from the word vitamine, which was coined in 1912 by Polish biochemist Casimir Funk, who isolated a complex of micronutrients essential to life, all of which he presumed to be amines.[10] When this presumption was later determined not to be true, the "e" was dropped from the name.[11]  All vitamins were discovered (identified) between 1913 and 1948[citation needed].
+
+from plant origin as provitamin A / all-trans-beta-carotene: orange, ripe yellow fruits, leafy vegetables, carrots, pumpkin, squash, spinach;
+
+Vitamins are classified as either water-soluble or fat-soluble. In humans there are 13 vitamins: 4 fat-soluble (A, D, E, and K) and 9 water-soluble (8 B vitamins and vitamin C). Water-soluble vitamins dissolve easily in water and, in general, are readily excreted from the body, to the degree that urinary output is a strong predictor of vitamin consumption.[24] Because they are not as readily stored, more consistent intake is important.[25] Fat-soluble vitamins are absorbed through the intestinal tract with the help of lipids (fats). Vitamins A and D can accumulate in the body, which can result in dangerous hypervitaminosis. Fat-soluble vitamin deficiency due to malabsorption is of particular significance in cystic fibrosis.[26]
+
+Anti-vitamins are chemical compounds that inhibit the absorption or actions of vitamins. For example, avidin is a protein in raw egg whites that inhibits the absorption of biotin; it is deactivated by cooking.[27] Pyrithiamine, a synthetic compound, has a molecular structure similar to thiamine, vitamin B1, and inhibits the enzymes that use thiamine.[28]
+
+Each vitamin is typically used in multiple reactions, and therefore most have multiple functions.[29]
+
+Vitamins are essential for the normal growth and development of a multicellular organism. Using the genetic blueprint inherited from its parents, a fetus develops from the nutrients it absorbs. It requires certain vitamins and minerals to be present at certain times.[9] These nutrients facilitate the chemical reactions that produce among other things, skin, bone, and muscle. If there is serious deficiency in one or more of these nutrients, a child may develop a deficiency disease. Even minor deficiencies may cause permanent damage.[30]
+
+Once growth and development are completed, vitamins remain essential nutrients for the healthy maintenance of the cells, tissues, and organs that make up a multicellular organism; they also enable a multicellular life form to efficiently use chemical energy provided by food it eats, and to help process the proteins, carbohydrates, and fats required for cellular respiration.[7]
+
+For the most part, vitamins are obtained from the diet, but some are acquired by other means: for example, microorganisms in the gut flora produce vitamin K and biotin; and one form of vitamin D is synthesized in skin cells when they are exposed to a certain wavelength of ultraviolet light present in sunlight. Humans can produce some vitamins from precursors they consume: for example, vitamin A is synthesized from beta carotene; and niacin is synthesized from the amino acid tryptophan.[31] The Food Fortification Initiative lists countries which have mandatory fortification programs for vitamins folic acid, niacin, vitamin A and vitamins B1, B2 and B12.[8]
+
+The body's stores for different vitamins vary widely; vitamins A, D, and B12 are stored in significant amounts, mainly in the liver,[20] and an adult's diet may be deficient in vitamins A and D for many months and B12 in some cases for years, before developing a deficiency condition. However, vitamin B3 (niacin and niacinamide) is not stored in significant amounts, so stores may last only a couple of weeks.[13][20] For vitamin C, the first symptoms of scurvy in experimental studies of complete vitamin C deprivation in humans have varied widely, from a month to more than six months, depending on previous dietary history that determined body stores.[32]
+
+Deficiencies of vitamins are classified as either primary or secondary. A primary deficiency occurs when an organism does not get enough of the vitamin in its food. A secondary deficiency may be due to an underlying disorder that prevents or limits the absorption or use of the vitamin, due to a "lifestyle factor", such as smoking, excessive alcohol consumption, or the use of medications that interfere with the absorption or use of the vitamin.[20] People who eat a varied diet are unlikely to develop a severe primary vitamin deficiency, but may be consuming less than the recommended amounts; a national food and supplement survey conducted in the US over 2003-2006 reported that over 90% of individuals who did not consume vitamin supplements were found to have inadequate levels of some of the essential vitamins, notably vitamins D and E.[33]
+
+Well-researched human vitamin deficiencies involve thiamine (beriberi), niacin (pellagra),[34] vitamin C (scurvy), folate (neural tube defects) and vitamin D (rickets).[35] In much of the developed world these deficiencies are rare due to an adequate supply of food and the  addition of vitamins to common foods.[20] In addition to these classical vitamin deficiency diseases, some evidence has also suggested links between vitamin deficiency and a number of different disorders.[36][37]
+
+Some vitamins have documented acute or chronic toxicity at larger intakes, which is referred to as hypertoxicity. The European Union and the governments of several countries have established Tolerable upper intake levels (ULs) for those vitamins which have documented toxicity (see table).[12][38][39] The likelihood of consuming too much of any vitamin from food is remote, but excessive intake (vitamin poisoning) from dietary supplements does occur. In 2016, overdose exposure to all formulations of vitamins and multi-vitamin/mineral formulations was reported by 63,931 individuals to the American Association of Poison Control Centers with 72% of these exposures in children under the age of five.[40] In the US, analysis of a national diet and supplement survey reported that about 7% of adult supplement users exceeded the UL for folate and 5% of those older than age 50 years exceeded the UL for vitamin A.[33]
+
+The USDA has conducted extensive studies on the percentage losses of various nutrients from food types and cooking methods.[41] Some vitamins may become more "bio-available" – that is, usable by the body – when foods are cooked.[42] The table below shows whether various vitamins are susceptible to loss from heat—such as heat from boiling, steaming, frying, etc. The effect of cutting vegetables can be seen from exposure to air and light. Water-soluble vitamins such as B and C dissolve into the water when a vegetable is boiled, and are then lost when the water is discarded.[43]
+
+In setting human nutrient guidelines, government organizations do not necessarily agree on amounts needed to avoid deficiency or maximum amounts to avoid the risk of toxicity.[38][12][39] For example, for vitamin C, recommended intakes range from 40 mg/day in India[44] to 155 mg/day for the European Union.[45] The table below shows U.S. Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for vitamins, PRIs for the European Union (same concept as RDAs), followed by what three government organizations deem to be the safe upper intake. RDAs are set higher than EARs to cover people with higher than average needs. Adequate Intakes (AIs) are set when there is not sufficient information to establish EARs and RDAs. Governments are slow to revise information of this nature. For the U.S. values, with the exception of calcium and vitamin D, all of the data date to 1997-2004.[46]
+
+EAR US Estimated Average Requirements.
+
+RDA US Recommended Dietary Allowances; higher for adults than for children, and may be even higher for women who are pregnant or lactating.
+
+AI  US and EFSA Adequate Intake; AIs established when there is not sufficient information to set EARs and RDAs.
+
+PRI Population Reference Intake is European Union equivalent of RDA; higher for adults than for children, and may be even higher for women who are pregnant or lactating. For Thiamin and Niacin the PRIs are expressed as amounts per MJ of calories consumed. MJ = megajoule = 239 food calories.
+
+UL or Upper Limit  Tolerable upper intake levels.
+
+ND  ULs have not been determined.
+
+NE  EARs have not been established.
+
+In those who are otherwise healthy, there is little evidence that supplements have any benefits with respect to cancer or heart disease.[47][48][49] Vitamin A and E supplements not only provide no health benefits for generally healthy individuals, but they may increase mortality, though the two large studies that support this conclusion included smokers for whom it was already known that beta-carotene supplements can be harmful.[48][50] A 2018 meta-analysis found no evidence that intake of vitamin D or calcium for community-dwelling elderly people reduced bone fractures.[51]
+
+Europe has regulations that define limits of vitamin (and mineral) dosages for their safe use as dietary supplements. Most vitamins that are sold as dietary supplements are not supposed to exceed a maximum daily dosage referred to as the tolerable upper intake level (UL or Upper Limit). Vitamin products above these regulatory limits are not considered supplements and should be registered as prescription or non-prescription (over-the-counter drugs) due to their potential side effects. The European Union, United States and Japan establish ULs.[12][38][39]
+
+Dietary supplements often contain vitamins, but may also include other ingredients, such as minerals, herbs, and botanicals. Scientific evidence supports the benefits of dietary supplements for persons with certain health conditions.[52] In some cases, vitamin supplements may have unwanted effects, especially if taken before surgery, with other dietary supplements or medicines, or if the person taking them has certain health conditions.[52] They may also contain levels of vitamins many times higher, and in different forms, than one may ingest through food.
+
+Most countries place dietary supplements in a special category under the general umbrella of foods, not drugs. As a result, the manufacturer, and not the government, has the responsibility of ensuring that its dietary supplement products are safe before they are marketed. Regulation of supplements varies widely by country. In the United States, a dietary supplement is defined under the Dietary Supplement Health and Education Act of 1994.[53] There is no FDA approval process for dietary supplements, and no requirement that manufacturers prove the safety or efficacy of supplements introduced before 1994.[34][35] The Food and Drug Administration must rely on its Adverse Event Reporting System to monitor adverse events that occur with supplements.[54] In 2007, the US Code of Federal Regulations (CFR) Title 21, part III took effect, regulating Good Manufacturing Practices (GMPs) in the manufacturing, packaging, labeling, or holding operations for dietary supplements. Even though product registration is not required, these regulations mandate production and quality control standards (including testing for identity, purity and adulterations) for dietary supplements.[55] In the European Union, the Food Supplements Directive requires that only those supplements that have been proven safe can be sold without a prescription.[56]
+For most vitamins, pharmacopoeial standards have been established. In the United States, the United States Pharmacopeia (USP) sets standards for the most commonly used vitamins and preparations thereof. Likewise, monographs of the European Pharmacopoeia (Ph.Eur.) regulate aspects of identity and purity for vitamins on the European market.
+
+The reason that the set of vitamins skips directly from E to K is that the vitamins corresponding to letters F–J were either reclassified over time, discarded as false leads, or renamed because of their relationship to vitamin B, which became a complex of vitamins.
+
+The German-speaking scientists who isolated and described vitamin K (in addition to naming it as such) did so because the vitamin is intimately involved in the coagulation of blood following wounding (from the German word Koagulation). At the time, most (but not all) of the letters from F through to J were already designated, so the use of the letter K was considered quite reasonable.[57][60] The table Nomenclature of reclassified vitamins lists chemicals that had previously been classified as vitamins, as well as the earlier names of vitamins that later became part of the B-complex.
+
+The missing B vitamins were reclassified or determined not to be vitamins. For example, B9 is folic acid and five of the folates are in the range B11 through B16.  Others, such as PABA (formerly B10), are biologically inactive, toxic, or with unclassifiable effects in humans, or not generally recognised as vitamins by science,[61] such as the highest-numbered, which some naturopath practitioners call B21 and B22. There are also nine lettered B complex vitamins (e.g., Bm). There are other D vitamins now recognised as other substances, which some sources of the same type number up to D7. The controversial cancer treatment laetrile was at one point lettered as vitamin B17. There appears to be no consensus on any vitamins Q, R, T, V, W, X, Y or Z, nor are there substances officially designated as vitamins N or I, although the latter may have been another form of one of the other vitamins or a known and named nutrient of another type.
+
+The value of eating certain foods to maintain health was recognized long before vitamins were identified. The ancient Egyptians knew that feeding liver to a person may help with night blindness, an illness now known to be caused by a vitamin A deficiency.[62] The advancement of ocean voyages during the Renaissance resulted in prolonged periods without access to fresh fruits and vegetables, and made illnesses from vitamin deficiency common among ships' crews.[63]
+
+In 1747, the Scottish surgeon James Lind discovered that citrus foods helped prevent scurvy, a particularly deadly disease in which collagen is not properly formed, causing poor wound healing, bleeding of the gums, severe pain, and death.[62] In 1753, Lind published his Treatise on the Scurvy, which recommended using lemons and limes to avoid scurvy, which was adopted by the British Royal Navy. This led to the nickname limey for British sailors. Lind's discovery, however, was not widely accepted by individuals in the Royal Navy's Arctic expeditions in the 19th century, where it was widely believed that scurvy could be prevented by practicing good hygiene, regular exercise, and maintaining the morale of the crew while on board, rather than by a diet of fresh food.[62] As a result, Arctic expeditions continued to be plagued by scurvy and other deficiency diseases. In the early 20th century, when Robert Falcon Scott made his two expeditions to the Antarctic, the prevailing medical theory at the time was that scurvy was caused by "tainted" canned food.[62]
+
+During the late 18th and early 19th centuries, the use of deprivation studies allowed scientists to isolate and identify a number of vitamins. Lipid from fish oil was used to cure rickets in rats, and the fat-soluble nutrient was called "antirachitic A". Thus, the first "vitamin" bioactivity ever isolated, which cured rickets, was initially called "vitamin A"; however, the bioactivity of this compound is now called vitamin D.[65] In 1881, Russian medical doctor Nikolai I. Lunin [ru] studied the effects of scurvy at the University of Tartu. He fed mice an artificial mixture of all the separate constituents of milk known at that time, namely the proteins, fats, carbohydrates, and salts. The mice that received only the individual constituents died, while the mice fed by milk itself developed normally. He made a conclusion that "a natural food such as milk must therefore contain, besides these known principal ingredients, small quantities of unknown substances essential to life." However, his conclusions were rejected by his advisor, Gustav von Bunge.[66] A similar result by Cornelius Pekelharing appeared in a Dutch medical journal in 1905, but it was not widely reported.[66]
+
+In East Asia, where polished white rice was the common staple food of the middle class, beriberi resulting from lack of vitamin B1 was endemic. In 1884, Takaki Kanehiro, a British-trained medical doctor of the Imperial Japanese Navy, observed that beriberi was endemic among low-ranking crew who often ate nothing but rice, but not among officers who consumed a Western-style diet. With the support of the Japanese navy, he experimented using crews of two battleships; one crew was fed only white rice, while the other was fed a diet of meat, fish, barley, rice, and beans. The group that ate only white rice documented 161 crew members with beriberi and 25 deaths, while the latter group had only 14 cases of beriberi and no deaths. This convinced Takaki and the Japanese Navy that diet was the cause of beriberi, but they mistakenly believed that sufficient amounts of protein prevented it.[67] That diseases could result from some dietary deficiencies was further investigated by Christiaan Eijkman, who in 1897 discovered that feeding unpolished rice instead of the polished variety to chickens helped to prevent a kind of polyneuritis that was the equivalent of beriberi.[34] The following year, Frederick Hopkins postulated that some foods contained "accessory factors" — in addition to proteins, carbohydrates, fats etc. — that are necessary for the functions of the human body.[62] Hopkins and Eijkman were awarded the Nobel Prize for Physiology or Medicine in 1929 for their discoveries.[68]
+
+In 1910, the first vitamin complex was isolated by Japanese scientist Umetaro Suzuki, who succeeded in extracting a water-soluble complex of micronutrients from rice bran and named it aberic acid (later Orizanin). He published this discovery in a Japanese scientific journal.[69] When the article was translated into German, the translation failed to state that it was a newly discovered nutrient, a claim made in the original Japanese article, and hence his discovery failed to gain publicity. In 1912 Polish-born biochemist Casimir Funk, working in London, isolated the same complex of micronutrients and proposed the complex be named "vitamine".[10] It was later to be known as vitamin B3 (niacin), though he described it as "anti-beri-beri-factor" (which would today be called thiamine or vitamin B1). Funk proposed the hypothesis that other diseases, such as rickets, pellagra, coeliac disease, and scurvy could also be cured by vitamins. Max Nierenstein a friend and reader of Biochemistry at Bristol University reportedly suggested the "vitamine" name (from "vital amine").[70][71] The name soon became synonymous with Hopkins' "accessory factors", and, by the time it was shown that not all vitamins are amines, the word was already ubiquitous. In 1920, Jack Cecil Drummond proposed that the final "e" be dropped to deemphasize the "amine" reference, hence "vitamin," after researchers began to suspect that not all "vitamines" (in particular, vitamin A) have an amine component.[67]
+
+The Nobel Prize in Physiology or Medicine for 1929 was awarded to Christiaan Eijkman and Sir Frederick Gowland Hopkins for their contributions to the discovery of vitamins.[72] Thirty-five years earlier, Eijkman had observed that chickens fed polished white rice developed neurological symptoms similar to those observed in military sailors and soldiers fed a rice-based diet, and that the symptoms were reversed when the chickens were switched to whole-grain rice. He called this "the anti-beriberi factor", which was later identified as vitamin B1, thiamine.[73]
+
+In 1930, Paul Karrer elucidated the correct structure for beta-carotene, the main precursor of vitamin A, and identified other carotenoids. Karrer and Norman Haworth confirmed Albert Szent-Györgyi's discovery of ascorbic acid and made significant contributions to the chemistry of flavins, which led to the identification of lactoflavin. For their investigations on carotenoids, flavins and vitamins A and B2, they both received the Nobel Prize in Chemistry in 1937.[74]
+
+In 1931, Albert Szent-Györgyi and a fellow researcher Joseph Svirbely suspected that "hexuronic acid" was actually vitamin C, and gave a sample to Charles Glen King, who proved its anti-scorbutic activity in his long-established guinea pig scorbutic assay. In 1937, Szent-Györgyi was awarded the Nobel Prize in Physiology or Medicine for his discovery. In 1943, Edward Adelbert Doisy and Henrik Dam were awarded the Nobel Prize in Physiology or Medicine for their discovery of vitamin K and its chemical structure. In 1967, George Wald was awarded the Nobel Prize (along with Ragnar Granit and Haldan Keffer Hartline) for his discovery that vitamin A could participate directly in a physiological process.[68]
+
+In 1938, Richard Kuhn was awarded the Nobel Prize in Chemistry for his work on carotenoids and vitamins, specifically B2 and B6.[75]
+
+Five people have been awarded Nobel Prizes for direct and indirect studies of vitamin B12: George Whipple, George Minot and William P. Murphy (1934), Alexander R. Todd (1957), and Dorothy Hodgkin (1964).[72]
+
+Once discovered, vitamins were actively promoted in articles and advertisements in McCall's, Good Housekeeping, and other media outlets.[34] Marketers enthusiastically promoted cod-liver oil, a source of Vitamin D, as "bottled sunshine", and bananas as a “natural vitality food". They promoted foods such as yeast cakes, a source of B vitamins, on the basis of scientifically-determined nutritional value, rather than taste or appearance.[76] World War II researchers focused on the need to ensure adequate nutrition, especially in processed foods.[34] Robert W. Yoder is credited with first using the term vitamania, in 1942, to describe the appeal of relying on nutritional supplements rather than on obtaining vitamins from a varied diet of foods. The continuing preoccupation with a healthy lifestyle has led to an obsessive consumption of additives the beneficial effects of which are questionable.[35]
+
+The term vitamin was derived from "vitamine", a compound word coined in 1912 by the Polish biochemist Casimir Funk[10][77] when working at the Lister Institute of Preventive Medicine. The name is from vital and amine, meaning amine of life, because it was suggested in 1912 that the organic micronutrient food factors that prevent beriberi and perhaps other similar dietary-deficiency diseases might be chemical amines. This was true of thiamine, but after it was found that other such micronutrients were not amines the word was shortened to vitamin in English.

en/6015.html.txt

@@ -0,0 +1,152 @@
+
+
+In everyday use and in kinematics, the speed of an object is the magnitude of the change of its position; it is thus a scalar quantity.[1] The average speed of an object in an interval of time is the distance travelled by the object divided by the duration of the interval;[2] the instantaneous speed is the limit of the average speed as the duration of the time interval approaches zero.
+
+Speed has the dimensions of distance divided by time. The SI unit of speed is the metre per second, but the most common unit of speed in everyday usage is the kilometre per hour or, in the US and the UK, miles per hour. For air and marine travel the knot is commonly used.
+
+The fastest possible speed at which energy or information can travel, according to special relativity, is the speed of light in a vacuum c = 299792458 metres per second (approximately 1079000000 km/h or 671000000 mph). Matter cannot quite reach the speed of light, as this would require an infinite amount of energy. In relativity physics, the concept of rapidity replaces the classical idea of speed.
+
+Italian physicist Galileo Galilei is usually credited with being the first to measure speed by considering the distance covered and the time it takes. Galileo defined speed as the distance covered per unit of time.[3] In equation form, that is
+
+where 
+
+
+
+v
+
+
+{\displaystyle v}
+
+ is speed, 
+
+
+
+d
+
+
+{\displaystyle d}
+
+ is distance, and 
+
+
+
+t
+
+
+{\displaystyle t}
+
+ is time. A cyclist who covers 30 metres in a time of 2 seconds, for example, has a speed of 15 metres per second. Objects in motion often have variations in speed (a car might travel along a street at 50 km/h, slow to 0 km/h, and then reach 30 km/h).
+
+Speed at some instant, or assumed constant during a very short period of time, is called instantaneous speed. By looking at a speedometer, one can read the instantaneous speed of a car at any instant.[3] A car travelling at 50 km/h generally goes for less than one hour at a constant speed, but if it did go at that speed for a full hour, it would travel 50 km. If the vehicle continued at that speed for half an hour, it would cover half that distance (25 km). If it continued for only one minute, it would cover about 833 m.
+
+In mathematical terms, the instantaneous speed 
+
+
+
+v
+
+
+{\displaystyle v}
+
+ is defined as the magnitude of the instantaneous velocity 
+
+
+
+
+v
+
+
+
+{\displaystyle {\boldsymbol {v}}}
+
+, that is, the derivative of the position 
+
+
+
+
+r
+
+
+
+{\displaystyle {\boldsymbol {r}}}
+
+ with respect to time:[2][4]
+
+If 
+
+
+
+s
+
+
+{\displaystyle s}
+
+ is the length of the path (also known as the distance) travelled until time 
+
+
+
+t
+
+
+{\displaystyle t}
+
+, the speed equals the time derivative of 
+
+
+
+s
+
+
+{\displaystyle s}
+
+:[2]
+
+In the special case where the velocity is constant (that is, constant speed in a straight line), this can be simplified to 
+
+
+
+v
+=
+s
+
+/
+
+t
+
+
+{\displaystyle v=s/t}
+
+.  The average speed over a finite time interval is the total distance travelled divided by the time duration.
+
+Different from instantaneous speed, average speed is defined as the total distance covered divided by the time interval. For example, if a distance of 80 kilometres is driven in 1 hour, the average speed is 80 kilometres per hour. Likewise, if 320 kilometres are travelled in 4 hours, the average speed is also 80 kilometres per hour. When a distance in kilometres (km) is divided by a time in hours (h), the result is in kilometres per hour (km/h).
+
+Average speed does not describe the speed variations that may have taken place during shorter time intervals (as it is the entire distance covered divided by the total time of travel), and so average speed is often quite different from a value of instantaneous speed.[3] If the average speed and the time of travel are known, the distance travelled can be calculated by rearranging the definition to
+
+Using this equation for an average speed of 80 kilometres per hour on a 4-hour trip, the distance covered is found to be 320 kilometres.
+
+Expressed in graphical language, the slope of a tangent line at any point of a distance-time graph is the instantaneous speed at this point, while the slope of a chord line of the same graph is the average speed during the time interval covered by the chord. Average speed of an object is
+Vav = s÷t
+
+Speed denotes only how fast an object is moving, whereas velocity describes both how fast and in which direction the object is moving.[5] If a car is said to travel at 60 km/h, its speed has been specified. However, if the car is said to move at 60 km/h to the north, its velocity has now been specified.
+
+The big difference can be discerned when considering movement around a circle. When something moves in a circular path and returns to its starting point, its average velocity is zero, but its average speed is found by dividing the circumference of the circle by the time taken to move around the circle. This is because the average velocity is calculated by considering only the displacement between the starting and end points, whereas the average speed considers only the total distance travelled.
+
+Linear speed is the distance travelled per unit of time, while tangential speed (or tangential velocity) is the linear speed of something moving along a circular path.[6] A point on the outside edge of a merry-go-round or turntable travels a greater distance in one complete rotation than a point nearer the center. Travelling a greater distance in the same time means a greater speed, and so linear speed is greater on the outer edge of a rotating object than it is closer to the axis. This speed along a circular path is known as tangential speed because the direction of motion is tangent to the circumference of the circle. For circular motion, the terms linear speed and tangential speed are used interchangeably, and both use units of m/s, km/h, and others.
+
+Rotational speed (or angular speed) involves the number of revolutions per unit of time. All parts of a rigid merry-go-round or turntable turn about the axis of rotation in the same amount of time. Thus, all parts share the same rate of rotation, or the same number of rotations or revolutions per unit of time. It is common to express rotational rates in revolutions per minute (RPM) or in terms of the number of "radians" turned in a unit of time. There are little more than 6 radians in a full rotation (2π radians exactly). When a direction is assigned to rotational speed, it is known as rotational velocity or angular velocity. Rotational velocity is a vector whose magnitude is the rotational speed.
+
+Tangential speed and rotational speed are related: the greater the RPMs, the larger the speed in metres per second. Tangential speed is directly proportional to rotational speed at any fixed distance from the axis of rotation.[6] However, tangential speed, unlike rotational speed, depends on radial distance (the distance from the axis). For a platform rotating with a fixed rotational speed, the tangential speed in the centre is zero. Towards the edge of the platform the tangential speed increases proportional to the distance from the axis.[7] In equation form:
+
+where v is tangential speed and ω (Greek letter omega) is rotational speed. One moves faster if the rate of rotation increases (a larger value for ω), and one also moves faster if movement farther from the axis occurs (a larger value for r). Move twice as far from the rotational axis at the centre and you move twice as fast. Move out three times as far and you have three times as much tangential speed. In any kind of rotating system, tangential speed depends on how far you are from the axis of rotation.
+
+When proper units are used for tangential speed v, rotational speed ω, and radial distance r, the direct proportion of v to both r and ω becomes the exact equation
+
+Thus, tangential speed will be directly proportional to r when all parts of a system simultaneously have the same ω, as for a wheel, disk, or rigid wand.
+
+Units of speed include:
+
+(* = approximate values)
+
+
+
+According to Jean Piaget, the intuition for the notion of speed in humans precedes that of duration, and is based on the notion of outdistancing.[11] Piaget studied this subject inspired by a question asked to him in 1928 by Albert Einstein: "In what order do children acquire the concepts of time and speed?"[12] Children's early concept of speed is based on "overtaking", taking only temporal and spatial orders into consideration, specifically: "A moving object is judged to be more rapid than another when at a given moment the first object is behind and a moment or so later ahead of the other object."[13]

en/6016.html.txt

@@ -0,0 +1,152 @@
+
+
+In everyday use and in kinematics, the speed of an object is the magnitude of the change of its position; it is thus a scalar quantity.[1] The average speed of an object in an interval of time is the distance travelled by the object divided by the duration of the interval;[2] the instantaneous speed is the limit of the average speed as the duration of the time interval approaches zero.
+
+Speed has the dimensions of distance divided by time. The SI unit of speed is the metre per second, but the most common unit of speed in everyday usage is the kilometre per hour or, in the US and the UK, miles per hour. For air and marine travel the knot is commonly used.
+
+The fastest possible speed at which energy or information can travel, according to special relativity, is the speed of light in a vacuum c = 299792458 metres per second (approximately 1079000000 km/h or 671000000 mph). Matter cannot quite reach the speed of light, as this would require an infinite amount of energy. In relativity physics, the concept of rapidity replaces the classical idea of speed.
+
+Italian physicist Galileo Galilei is usually credited with being the first to measure speed by considering the distance covered and the time it takes. Galileo defined speed as the distance covered per unit of time.[3] In equation form, that is
+
+where 
+
+
+
+v
+
+
+{\displaystyle v}
+
+ is speed, 
+
+
+
+d
+
+
+{\displaystyle d}
+
+ is distance, and 
+
+
+
+t
+
+
+{\displaystyle t}
+
+ is time. A cyclist who covers 30 metres in a time of 2 seconds, for example, has a speed of 15 metres per second. Objects in motion often have variations in speed (a car might travel along a street at 50 km/h, slow to 0 km/h, and then reach 30 km/h).
+
+Speed at some instant, or assumed constant during a very short period of time, is called instantaneous speed. By looking at a speedometer, one can read the instantaneous speed of a car at any instant.[3] A car travelling at 50 km/h generally goes for less than one hour at a constant speed, but if it did go at that speed for a full hour, it would travel 50 km. If the vehicle continued at that speed for half an hour, it would cover half that distance (25 km). If it continued for only one minute, it would cover about 833 m.
+
+In mathematical terms, the instantaneous speed 
+
+
+
+v
+
+
+{\displaystyle v}
+
+ is defined as the magnitude of the instantaneous velocity 
+
+
+
+
+v
+
+
+
+{\displaystyle {\boldsymbol {v}}}
+
+, that is, the derivative of the position 
+
+
+
+
+r
+
+
+
+{\displaystyle {\boldsymbol {r}}}
+
+ with respect to time:[2][4]
+
+If 
+
+
+
+s
+
+
+{\displaystyle s}
+
+ is the length of the path (also known as the distance) travelled until time 
+
+
+
+t
+
+
+{\displaystyle t}
+
+, the speed equals the time derivative of 
+
+
+
+s
+
+
+{\displaystyle s}
+
+:[2]
+
+In the special case where the velocity is constant (that is, constant speed in a straight line), this can be simplified to 
+
+
+
+v
+=
+s
+
+/
+
+t
+
+
+{\displaystyle v=s/t}
+
+.  The average speed over a finite time interval is the total distance travelled divided by the time duration.
+
+Different from instantaneous speed, average speed is defined as the total distance covered divided by the time interval. For example, if a distance of 80 kilometres is driven in 1 hour, the average speed is 80 kilometres per hour. Likewise, if 320 kilometres are travelled in 4 hours, the average speed is also 80 kilometres per hour. When a distance in kilometres (km) is divided by a time in hours (h), the result is in kilometres per hour (km/h).
+
+Average speed does not describe the speed variations that may have taken place during shorter time intervals (as it is the entire distance covered divided by the total time of travel), and so average speed is often quite different from a value of instantaneous speed.[3] If the average speed and the time of travel are known, the distance travelled can be calculated by rearranging the definition to
+
+Using this equation for an average speed of 80 kilometres per hour on a 4-hour trip, the distance covered is found to be 320 kilometres.
+
+Expressed in graphical language, the slope of a tangent line at any point of a distance-time graph is the instantaneous speed at this point, while the slope of a chord line of the same graph is the average speed during the time interval covered by the chord. Average speed of an object is
+Vav = s÷t
+
+Speed denotes only how fast an object is moving, whereas velocity describes both how fast and in which direction the object is moving.[5] If a car is said to travel at 60 km/h, its speed has been specified. However, if the car is said to move at 60 km/h to the north, its velocity has now been specified.
+
+The big difference can be discerned when considering movement around a circle. When something moves in a circular path and returns to its starting point, its average velocity is zero, but its average speed is found by dividing the circumference of the circle by the time taken to move around the circle. This is because the average velocity is calculated by considering only the displacement between the starting and end points, whereas the average speed considers only the total distance travelled.
+
+Linear speed is the distance travelled per unit of time, while tangential speed (or tangential velocity) is the linear speed of something moving along a circular path.[6] A point on the outside edge of a merry-go-round or turntable travels a greater distance in one complete rotation than a point nearer the center. Travelling a greater distance in the same time means a greater speed, and so linear speed is greater on the outer edge of a rotating object than it is closer to the axis. This speed along a circular path is known as tangential speed because the direction of motion is tangent to the circumference of the circle. For circular motion, the terms linear speed and tangential speed are used interchangeably, and both use units of m/s, km/h, and others.
+
+Rotational speed (or angular speed) involves the number of revolutions per unit of time. All parts of a rigid merry-go-round or turntable turn about the axis of rotation in the same amount of time. Thus, all parts share the same rate of rotation, or the same number of rotations or revolutions per unit of time. It is common to express rotational rates in revolutions per minute (RPM) or in terms of the number of "radians" turned in a unit of time. There are little more than 6 radians in a full rotation (2π radians exactly). When a direction is assigned to rotational speed, it is known as rotational velocity or angular velocity. Rotational velocity is a vector whose magnitude is the rotational speed.
+
+Tangential speed and rotational speed are related: the greater the RPMs, the larger the speed in metres per second. Tangential speed is directly proportional to rotational speed at any fixed distance from the axis of rotation.[6] However, tangential speed, unlike rotational speed, depends on radial distance (the distance from the axis). For a platform rotating with a fixed rotational speed, the tangential speed in the centre is zero. Towards the edge of the platform the tangential speed increases proportional to the distance from the axis.[7] In equation form:
+
+where v is tangential speed and ω (Greek letter omega) is rotational speed. One moves faster if the rate of rotation increases (a larger value for ω), and one also moves faster if movement farther from the axis occurs (a larger value for r). Move twice as far from the rotational axis at the centre and you move twice as fast. Move out three times as far and you have three times as much tangential speed. In any kind of rotating system, tangential speed depends on how far you are from the axis of rotation.
+
+When proper units are used for tangential speed v, rotational speed ω, and radial distance r, the direct proportion of v to both r and ω becomes the exact equation
+
+Thus, tangential speed will be directly proportional to r when all parts of a system simultaneously have the same ω, as for a wheel, disk, or rigid wand.
+
+Units of speed include:
+
+(* = approximate values)
+
+
+
+According to Jean Piaget, the intuition for the notion of speed in humans precedes that of duration, and is based on the notion of outdistancing.[11] Piaget studied this subject inspired by a question asked to him in 1928 by Albert Einstein: "In what order do children acquire the concepts of time and speed?"[12] Children's early concept of speed is based on "overtaking", taking only temporal and spatial orders into consideration, specifically: "A moving object is judged to be more rapid than another when at a given moment the first object is behind and a moment or so later ahead of the other object."[13]

en/6017.html.txt

@@ -0,0 +1,34 @@
+Vitry-sur-Seine (French pronunciation: ​[vi.tʁi.syʁ.sɛn]) is a commune in the southeastern suburbs of Paris, France. It is located 7.5 km (4.7 mi) from the centre of Paris.
+
+Vitry-sur-Seine was originally called simply Vitry. The name Vitry comes from Medieval Latin Vitriacum, and before that Victoriacum, meaning "estate of Victorius", a Gallo-Roman landowner. In 1897 the name of the commune officially became Vitry-sur-Seine (meaning "Vitry upon Seine"), in order to distinguish it from other communes of France also called Vitry.
+
+For some years, Vitry-sur-Seine operated a cultural policy of bringing art to all. For this reason, the commune contains over 100 contemporary sculptures, notably in establishments of public education (schools, secondary schools and High Schools).
+
+Vitry hosts the Musée d'Art Contemporain du Val-de-Marne (Val-de-Marne's Museum of Contemporary Art). Opened on 18 November 2005, this museum offers in addition to the workshops of plastic arts, an auditorium and a cinema for art and experimental film.
+
+Vitry is one of the cities that contributed to the development of the Hip hop movement in France. Consequentially, urban art has a very important place in the city
+
+Vitry-sur-Seine is served by two stations on Paris RER line C: Vitry-sur-Seine and Les Ardoines.
+
+Orly Airport is located near Vitry-sur-Seine.
+
+The city can be separated into three distinct parts: the center containing numerous cités HLM (Housing projects), peripheral neighborhoods belonging to the middle class, and a large industrial area along the Seine river.
+
+The bordering towns are Ivry-sur-Seine, Villejuif, Chevilly-Larue, Thiais, Choisy-le-Roi, Alfortville.
+
+In 2008 the population of the city was estimated at 82,500 inhabitants. The rate of unemployment is 26.5%, while national average is under 10%
+Vitry-sur-Seine is the fiftieth most populated city of France and the tenth of Île-de-France.
+
+2 An immigrant is a person born in a foreign country not having French citizenship at birth. Note that an immigrant may have acquired French citizenship since moving to France, but is still considered an immigrant in French statistics. On the other hand, persons born in France with foreign citizenship (the children of immigrants) are not listed as immigrants.
+
+As of circa 1998 Ivry-sur-Seine and Vitry had a combined Asian population of 3,600. That year about 250 Asians from those communes worked in the 13th arrondissement of Paris, and the overall demographics of Ivry and Vitry Asians were similar to those in the 13th arrondissement.[2]
+
+Vitry is divided into two cantons (districts):
+
+As of 2016[update] the commune has 23 preschools (maternelles),[3] and 21 elementary schools,[4] with a combined total of 9,000 students.[5]
+
+Paris 12 Val de Marne University is the area university.[8]
+
+Vitry-sur-Seine is twinned with:
+[9]
+

en/6018.html.txt

@@ -0,0 +1,170 @@
+
+
+Life on Earth:
+
+Life is a characteristic that distinguishes physical entities that have biological processes, such as signaling and self-sustaining processes, from those that do not, either because such functions have ceased (they have died), or because they never had such functions and are classified as inanimate. Various forms of life exist, such as plants, animals, fungi, protists, archaea, and bacteria. Biology is the science concerned with the study of life.
+
+There is currently no consensus regarding the definition of life. One popular definition is that organisms are open systems that maintain homeostasis, are composed of cells, have a life cycle, undergo metabolism, can grow, adapt to their environment, respond to stimuli, reproduce and evolve. Other definitions sometimes include non-cellular life forms such as viruses and viroids.
+
+Abiogenesis is the natural process of life arising from non-living matter, such as simple organic compounds. The prevailing scientific hypothesis is that the transition from non-living to living entities was not a single event, but a gradual process of increasing complexity. Life on Earth first appeared as early as 4.28 billion years ago, soon after ocean formation 4.41 billion years ago, and not long after the formation of the Earth 4.54 billion years ago.[1][2][3][4] The earliest known life forms are microfossils of bacteria.[5][6] Researchers generally think that current life on Earth descends from an RNA world,[7] although RNA-based life may not have been the first life to have existed.[8][9] The classic 1952 Miller–Urey experiment and similar research demonstrated that most amino acids, the chemical constituents of the proteins used in all living organisms, can be synthesized from inorganic compounds under conditions intended to replicate those of the early Earth. Complex organic molecules occur in the Solar System and in interstellar space, and these molecules may have provided starting material for the development of life on Earth.[10][11][12][13]
+
+Since its primordial beginnings, life on Earth has changed its environment on a geologic time scale, but it has also adapted to survive in most ecosystems and conditions. Some microorganisms, called extremophiles, thrive in physically or geochemically extreme environments that are detrimental to most other life on Earth. The cell is considered the structural and functional unit of life.[14][15] There are two kinds of cells, prokaryotic and eukaryotic, both of which consist of cytoplasm enclosed within a membrane and contain many biomolecules such as proteins and nucleic acids. Cells reproduce through a process of cell division, in which the parent cell divides into two or more daughter cells.
+
+In the past, there have been many attempts to define what is meant by "life" through obsolete concepts such as odic force, hylomorphism, spontaneous generation and vitalism, that have now been disproved by biological discoveries. Aristotle is considered to be the first person to classify organisms. Later, Carl Linnaeus introduced his system of binomial nomenclature for the classification of species. Eventually new groups and categories of life were discovered, such as cells and microorganisms, forcing dramatic revisions of the structure of relationships between living organisms. Though currently only known on Earth, life need not be restricted to it, and many scientists speculate in the existence of extraterrestrial life. Artificial life is a computer simulation or human-made reconstruction of any aspect of life, which is often used to examine systems related to natural life.
+
+Death is the permanent termination of all biological functions which sustain an organism, and as such, is the end of its life. Extinction is the term describing the dying out of a group or taxon, usually a species. Fossils are the preserved remains or traces of organisms.
+
+The definition of life has long been a challenge for scientists and philosophers, with many varied definitions put forward.[16][17][18] This is partially because life is a process, not a substance.[19][20][21] This is complicated by a lack of knowledge of the characteristics of living entities, if any, that may have developed outside of Earth.[22][23] Philosophical definitions of life have also been put forward, with similar difficulties on how to distinguish living things from the non-living.[24] Legal definitions of life have also been described and debated, though these generally focus on the decision to declare a human dead, and the legal ramifications of this decision.[25]
+
+Since there is no unequivocal definition of life, most current definitions in biology are descriptive. Life is considered a characteristic of something that preserves, furthers or reinforces its existence in the given environment. This characteristic exhibits all or most of the following traits:[18][26][27][28][29][30][31]
+
+These complex processes, called physiological functions, have underlying physical and chemical bases, as well as signaling and control mechanisms that are essential to maintaining life.
+
+From a physics perspective, living beings are thermodynamic systems with an organized molecular structure that can reproduce itself and evolve as survival dictates.[32][33] Thermodynamically, life has been described as an open system which makes use of gradients in its surroundings to create imperfect copies of itself.[34] Hence, life is a self-sustained chemical system capable of undergoing Darwinian evolution.[35][36] A major strength of this definition is that it distinguishes life by the evolutionary process rather than its chemical composition.[37]
+
+Others take a systemic viewpoint that does not necessarily depend on molecular chemistry. One systemic definition of life is that living things are self-organizing and autopoietic (self-producing). Variations of this definition include Stuart Kauffman's definition as an autonomous agent or a multi-agent system capable of reproducing itself or themselves, and of completing at least one thermodynamic work cycle.[38] This definition is extended by the apparition of novel functions over time.[39]
+
+Whether or not viruses should be considered as alive is controversial. They are most often considered as just replicators rather than forms of life.[40] They have been described as "organisms at the edge of life"[41] because they possess genes, evolve by natural selection,[42][43] and replicate by creating multiple copies of themselves through self-assembly. However, viruses do not metabolize and they require a host cell to make new products. Virus self-assembly within host cells has implications for the study of the origin of life, as it may support the hypothesis that life could have started as self-assembling organic molecules.[44][45][46]
+
+To reflect the minimum phenomena required, other biological definitions of life have been proposed,[47] with many of these being based upon chemical systems. Biophysicists have commented that living things function on negative entropy.[48][49] In other words, living processes can be viewed as a delay of the spontaneous diffusion or dispersion of the internal energy of biological molecules towards more potential microstates.[16] In more detail, according to physicists such as John Bernal, Erwin Schrödinger, Eugene Wigner, and John Avery, life is a member of the class of phenomena that are open or continuous systems able to decrease their internal entropy at the expense of substances or free energy taken in from the environment and subsequently rejected in a degraded form.[50][51]
+
+Living systems are open self-organizing living things that interact with their environment. These systems are maintained by flows of information, energy, and matter.
+
+Budisa, Kubyshkin and Schmidt defined cellular life as an organizational unit resting on four pillars/cornerstones: (i) energy, (ii) metabolism, (iii) information and (iv) form. This system is able to regulate and control metabolism and energy supply and contains at least one subsystem that functions as an information carrier (genetic information). Cells as self-sustaining units are parts of different populations that are involved in the unidirectional and irreversible open-ended process known as evolution.[52]
+
+Some scientists have proposed in the last few decades that a general living systems theory is required to explain the nature of life.[53] Such a general theory would arise out of the ecological and biological sciences and attempt to map general principles for how all living systems work. Instead of examining phenomena by attempting to break things down into components, a general living systems theory explores phenomena in terms of dynamic patterns of the relationships of organisms with their environment.[54]
+
+The idea that the Earth is alive is found in philosophy and religion, but the first scientific discussion of it was by the Scottish scientist James Hutton. In 1785, he stated that the Earth was a superorganism and that its proper study should be physiology. Hutton is considered the father of geology, but his idea of a living Earth was forgotten in the intense reductionism of the 19th century.[55]:10 The Gaia hypothesis, proposed in the 1960s by scientist James Lovelock,[56][57] suggests that life on Earth functions as a single organism that defines and maintains environmental conditions necessary for its survival.[55] This hypothesis served as one of the foundations of the modern Earth system science.
+
+The first attempt at a general living systems theory for explaining the nature of life was in 1978, by American biologist James Grier Miller.[58] Robert Rosen (1991) built on this by defining a system component as "a unit of organization; a part with a function, i.e., a definite relation between part and whole." From this and other starting concepts, he developed a "relational theory of systems" that attempts to explain the special properties of life. Specifically, he identified the "nonfractionability of components in an organism" as the fundamental difference between living systems and "biological machines."[59]
+
+A systems view of life treats environmental fluxes and biological fluxes together as a "reciprocity of influence,"[60] and a reciprocal relation with environment is arguably as important for understanding life as it is for understanding ecosystems. As Harold J. Morowitz (1992) explains it, life is a property of an ecological system rather than a single organism or species.[61] He argues that an ecosystemic definition of life is preferable to a strictly biochemical or physical one. Robert Ulanowicz (2009) highlights mutualism as the key to understand the systemic, order-generating behavior of life and ecosystems.[62]
+
+Complex systems biology (CSB) is a field of science that studies the emergence of complexity in functional organisms from the viewpoint of dynamic systems theory.[63] The latter is also often called systems biology and aims to understand the most fundamental aspects of life. A closely related approach to CSB and systems biology called relational biology is concerned mainly with understanding life processes in terms of the most important relations, and categories of such relations among the essential functional components of organisms; for multicellular organisms, this has been defined as "categorical biology", or a model representation of organisms as a category theory of biological relations, as well as an algebraic topology of the functional organization of living organisms in terms of their dynamic, complex networks of metabolic, genetic, and epigenetic processes and signaling pathways.[64][65] Alternative but closely related approaches focus on the interdependance of constraints, where constraints can be either molecular, such as enzymes, or macroscopic, such as the geometry of a bone or of the vascular system.[66]
+
+It has also been argued that the evolution of order in living systems and certain physical systems obeys a common fundamental principle termed the Darwinian dynamic.[67][68] The Darwinian dynamic was formulated by first considering how macroscopic order is generated in a simple non-biological system far from thermodynamic equilibrium, and then extending consideration to short, replicating RNA molecules. The underlying order-generating process was concluded to be basically similar for both types of systems.[67]
+
+Another systemic definition called the operator theory proposes that "life is a general term for the presence of the typical closures found in organisms; the typical closures are a membrane and an autocatalytic set in the cell"[69] and that an organism is any system with an organisation that complies with an operator type that is at least as complex as the cell.[70][71][72][73] Life can also be modeled as a network of inferior negative feedbacks of regulatory mechanisms subordinated to a superior positive feedback formed by the potential of expansion and reproduction.[74]
+
+Some of the earliest theories of life were materialist, holding that all that exists is matter, and that life is merely a complex form or arrangement of matter. Empedocles (430 BC) argued that everything in the universe is made up of a combination of four eternal "elements" or "roots of all": earth, water, air, and fire. All change is explained by the arrangement and rearrangement of these four elements. The various forms of life are caused by an appropriate mixture of elements.[75]
+
+Democritus (460 BC) thought that the essential characteristic of life is having a soul (psyche). Like other ancient writers, he was attempting to explain what makes something a living thing. His explanation was that fiery atoms make a soul in exactly the same way atoms and void account for any other thing. He elaborates on fire because of the apparent connection between life and heat, and because fire moves.[76]
+
+Plato's world of eternal and unchanging Forms, imperfectly represented in matter by a divine Artisan, contrasts sharply with the various mechanistic Weltanschauungen, of which atomism was, by the fourth century at least, the most prominent ... This debate persisted throughout the ancient world. Atomistic mechanism got a shot in the arm from Epicurus ... while the Stoics adopted a divine teleology ... The choice seems simple: either show how a structured, regular world could arise out of undirected processes, or inject intelligence into the system.[77]
+
+The mechanistic materialism that originated in ancient Greece was revived and revised by the French philosopher René Descartes, who held that animals and humans were assemblages of parts that together functioned as a machine. In the 19th century, the advances in cell theory in biological science encouraged this view. The evolutionary theory of Charles Darwin (1859) is a mechanistic explanation for the origin of species by means of natural selection.[78]
+
+Hylomorphism is a theory first expressed by the Greek philosopher Aristotle (322 BC). The application of hylomorphism to biology was important to Aristotle, and biology is extensively covered in his extant writings. In this view, everything in the material universe has both matter and form, and the form of a living thing is its soul (Greek psyche, Latin anima). There are three kinds of souls: the vegetative soul of plants, which causes them to grow and decay and nourish themselves, but does not cause motion and sensation; the animal soul, which causes animals to move and feel; and the rational soul, which is the source of consciousness and reasoning, which (Aristotle believed) is found only in man.[79] Each higher soul has all of the attributes of the lower ones. Aristotle believed that while matter can exist without form, form cannot exist without matter, and that therefore the soul cannot exist without the body.[80]
+
+This account is consistent with teleological explanations of life, which account for phenomena in terms of purpose or goal-directedness. Thus, the whiteness of the polar bear's coat is explained by its purpose of camouflage. The direction of causality (from the future to the past) is in contradiction with the scientific evidence for natural selection, which explains the consequence in terms of a prior cause. Biological features are explained not by looking at future optimal results, but by looking at the past evolutionary history of a species, which led to the natural selection of the features in question.[81]
+
+Spontaneous generation was the belief that living organisms can form without descent from similar organisms. Typically, the idea was that certain forms such as fleas could arise from inanimate matter such as dust or the supposed seasonal generation of mice and insects from mud or garbage.[82]
+
+The theory of spontaneous generation was proposed by Aristotle,[83] who compiled and expanded the work of prior natural philosophers and the various ancient explanations of the appearance of organisms; it held sway for two millennia. It was decisively dispelled by the experiments of Louis Pasteur in 1859, who expanded upon the investigations of predecessors such as Francesco Redi.[84][85] Disproof of the traditional ideas of spontaneous generation is no longer controversial among biologists.[86][87][88]
+
+Vitalism is the belief that the life-principle is non-material. This originated with Georg Ernst Stahl (17th century), and remained popular until the middle of the 19th century. It appealed to philosophers such as Henri Bergson, Friedrich Nietzsche, and Wilhelm Dilthey,[89] anatomists like Xavier Bichat, and chemists like Justus von Liebig.[90] Vitalism included the idea that there was a fundamental difference between organic and inorganic material, and the belief that organic material can only be derived from living things. This was disproved in 1828, when Friedrich Wöhler prepared urea from inorganic materials.[91] This Wöhler synthesis is considered the starting point of modern organic chemistry. It is of historical significance because for the first time an organic compound was produced in inorganic reactions.[90]
+
+During the 1850s, Hermann von Helmholtz, anticipated by Julius Robert von Mayer, demonstrated that no energy is lost in muscle movement, suggesting that there were no "vital forces" necessary to move a muscle.[92] These results led to the abandonment of scientific interest in vitalistic theories, although the belief lingered on in pseudoscientific theories such as homeopathy, which interprets diseases and sickness as caused by disturbances in a hypothetical vital force or life force.[93]
+
+The age of the Earth is about 4.54 billion years.[94][95][96] Evidence suggests that life on Earth has existed for at least 3.5 billion years,[97][98][99][100][101][102][103][104][105] with the oldest physical traces of life dating back 3.7 billion years;[106][107][108] however, some theories, such as the Late Heavy Bombardment theory, suggest that life on Earth may have started even earlier, as early as 4.1–4.4 billion years ago,[97][98][99][100][101] and the chemistry leading to life may have begun shortly after the Big Bang, 13.8 billion years ago, during an epoch when the universe was only 10–17 million years old.[109][110][111]
+
+More than 99% of all species of life forms, amounting to over five billion species,[112] that ever lived on Earth are estimated to be extinct.[113][114]
+
+Although the number of Earth's catalogued species of lifeforms is between 1.2 million and 2 million,[115][116] the total number of species in the planet is uncertain. Estimates range from 8 million to 100 million,[115][116] with a more narrow range between 10 and 14 million,[115] but it may be as high as 1 trillion (with only one-thousandth of one percent of the species described) according to studies realized in May 2016.[117][118] The total number of related DNA base pairs on Earth is estimated at 5.0 x 1037 and weighs 50 billion tonnes.[119] In comparison, the total mass of the biosphere has been estimated to be as much as 4 TtC (trillion tons of carbon).[120] In July 2016, scientists reported identifying a set of 355 genes from the Last Universal Common Ancestor (LUCA) of all organisms living on Earth.[121]
+
+All known life forms share fundamental molecular mechanisms, reflecting their common descent; based on these observations, hypotheses on the origin of life attempt to find a mechanism explaining the formation of a universal common ancestor, from simple organic molecules via pre-cellular life to protocells and metabolism. Models have been divided into "genes-first" and "metabolism-first" categories, but a recent trend is the emergence of hybrid models that combine both categories.[122]
+
+There is no current scientific consensus as to how life originated. However, most accepted scientific models build on the Miller–Urey experiment and the work of Sidney Fox, which show that conditions on the primitive Earth favored chemical reactions that synthesize amino acids and other organic compounds from inorganic precursors,[123] and phospholipids spontaneously form lipid bilayers, the basic structure of a cell membrane.
+
+Living organisms synthesize proteins, which are polymers of amino acids using instructions encoded by deoxyribonucleic acid (DNA). Protein synthesis entails intermediary ribonucleic acid (RNA) polymers. One possibility for how life began is that genes originated first, followed by proteins;[124] the alternative being that proteins came first and then genes.[125]
+
+However, because genes and proteins are both required to produce the other, the problem of considering which came first is like that of the chicken or the egg. Most scientists have adopted the hypothesis that because of this, it is unlikely that genes and proteins arose independently.[126]
+
+Therefore, a possibility, first suggested by Francis Crick,[127] is that the first life was based on RNA,[126] which has the DNA-like properties of information storage and the catalytic properties of some proteins. This is called the RNA world hypothesis, and it is supported by the observation that many of the most critical components of cells (those that evolve the slowest) are composed mostly or entirely of RNA. Also, many critical cofactors (ATP, Acetyl-CoA, NADH, etc.) are either nucleotides or substances clearly related to them. The catalytic properties of RNA had not yet been demonstrated when the hypothesis was first proposed,[128] but they were confirmed by Thomas Cech in 1986.[129]
+
+One issue with the RNA world hypothesis is that synthesis of RNA from simple inorganic precursors is more difficult than for other organic molecules. One reason for this is that RNA precursors are very stable and react with each other very slowly under ambient conditions, and it has also been proposed that living organisms consisted of other molecules before RNA.[130] However, the successful synthesis of certain RNA molecules under the conditions that existed prior to life on Earth has been achieved by adding alternative precursors in a specified order with the precursor phosphate present throughout the reaction.[131] This study makes the RNA world hypothesis more plausible.[132]
+
+Geological findings in 2013 showed that reactive phosphorus species (like phosphite) were in abundance in the ocean before 3.5 Ga, and that Schreibersite easily reacts with aqueous glycerol to generate phosphite and glycerol 3-phosphate.[133] It is hypothesized that Schreibersite-containing meteorites from the Late Heavy Bombardment could have provided early reduced phosphorus, which could react with prebiotic organic molecules to form phosphorylated biomolecules, like RNA.[133]
+
+In 2009, experiments demonstrated Darwinian evolution of a two-component system of RNA enzymes (ribozymes) in vitro.[134] The work was performed in the laboratory of Gerald Joyce, who stated "This is the first example, outside of biology, of evolutionary adaptation in a molecular genetic system."[135]
+
+Prebiotic compounds may have originated extraterrestrially. NASA findings in 2011, based on studies with meteorites found on Earth, suggest DNA and RNA components (adenine, guanine and related organic molecules) may be formed in outer space.[136][137][138][139]
+
+In March 2015, NASA scientists reported that, for the first time, complex DNA and RNA organic compounds of life, including uracil, cytosine and thymine, have been formed in the laboratory under outer space conditions, using starting chemicals, such as pyrimidine, found in meteorites. Pyrimidine, like polycyclic aromatic hydrocarbons (PAHs), the most carbon-rich chemical found in the universe, may have been formed in red giants or in interstellar dust and gas clouds, according to the scientists.[140]
+
+According to the panspermia hypothesis, microscopic life—distributed by meteoroids, asteroids and other small Solar System bodies—may exist throughout the universe.[141][142]
+
+The diversity of life on Earth is a result of the dynamic interplay between genetic opportunity, metabolic capability, environmental challenges,[143] and symbiosis.[144][145][146] For most of its existence, Earth's habitable environment has been dominated by microorganisms and subjected to their metabolism and evolution. As a consequence of these microbial activities, the physical-chemical environment on Earth has been changing on a geologic time scale, thereby affecting the path of evolution of subsequent life.[143] For example, the release of molecular oxygen by cyanobacteria as a by-product of photosynthesis induced global changes in the Earth's environment. Because oxygen was toxic to most life on Earth at the time, this posed novel evolutionary challenges, and ultimately resulted in the formation of Earth's major animal and plant species. This interplay between organisms and their environment is an inherent feature of living systems.[143]
+
+The biosphere is the global sum of all ecosystems. It can also be termed as the zone of life on Earth, a closed system (apart from solar and cosmic radiation and heat from the interior of the Earth), and largely self-regulating.[147] By the most general biophysiological definition, the biosphere is the global ecological system integrating all living beings and their relationships, including their interaction with the elements of the lithosphere, geosphere, hydrosphere, and atmosphere.
+
+Life forms live in every part of the Earth's biosphere, including soil, hot springs, inside rocks at least 19 km (12 mi) deep underground, the deepest parts of the ocean, and at least 64 km (40 mi) high in the atmosphere.[148][149][150] Under certain test conditions, life forms have been observed to thrive in the near-weightlessness of space[151][152] and to survive in the vacuum of outer space.[153][154] Life forms appear to thrive in the Mariana Trench, the deepest spot in the Earth's oceans.[155][156] Other researchers reported related studies that life forms thrive inside rocks up to 580 m (1,900 ft; 0.36 mi) below the sea floor under 2,590 m (8,500 ft; 1.61 mi) of ocean off the coast of the northwestern United States,[155][157] as well as 2,400 m (7,900 ft; 1.5 mi) beneath the seabed off Japan.[158] In August 2014, scientists confirmed the existence of life forms living 800 m (2,600 ft; 0.50 mi) below the ice of Antarctica.[159][160] According to one researcher, "You can find microbes everywhere—they're extremely adaptable to conditions, and survive wherever they are."[155]
+
+The biosphere is postulated to have evolved, beginning with a process of biopoesis (life created naturally from non-living matter, such as simple organic compounds) or biogenesis (life created from living matter), at least some 3.5 billion years ago.[161][162] The earliest evidence for life on Earth includes biogenic graphite found in 3.7 billion-year-old metasedimentary rocks from Western Greenland[106] and microbial mat fossils found in 3.48 billion-year-old sandstone from Western Australia.[107][108] More recently, in 2015, "remains of biotic life" were found in 4.1 billion-year-old rocks in Western Australia.[98][99] In 2017, putative fossilized microorganisms (or microfossils) were announced to have been discovered in hydrothermal vent precipitates in the Nuvvuagittuq Belt of Quebec, Canada that were as old as 4.28 billion years, the oldest record of life on earth, suggesting "an almost instantaneous emergence of life" after ocean formation 4.4 billion years ago, and not long after the formation of the Earth 4.54 billion years ago.[1][2][3][4] According to biologist Stephen Blair Hedges, "If life arose relatively quickly on Earth ... then it could be common in the universe."[98]
+
+In a general sense, biospheres are any closed, self-regulating systems containing ecosystems. This includes artificial biospheres such as Biosphere 2 and BIOS-3, and potentially ones on other planets or moons.[163]
+
+The inert components of an ecosystem are the physical and chemical factors necessary for life—energy (sunlight or chemical energy), water, heat, atmosphere, gravity, nutrients, and ultraviolet solar radiation protection.[164] In most ecosystems, the conditions vary during the day and from one season to the next. To live in most ecosystems, then, organisms must be able to survive a range of conditions, called the "range of tolerance."[165] Outside that are the "zones of physiological stress," where the survival and reproduction are possible but not optimal. Beyond these zones are the "zones of intolerance," where survival and reproduction of that organism is unlikely or impossible. Organisms that have a wide range of tolerance are more widely distributed than organisms with a narrow range of tolerance.[165]
+
+To survive, selected microorganisms can assume forms that enable them to withstand freezing, complete desiccation, starvation, high levels of radiation exposure, and other physical or chemical challenges. These microorganisms may survive exposure to such conditions for weeks, months, years, or even centuries.[143] Extremophiles are microbial life forms that thrive outside the ranges where life is commonly found.[166] They excel at exploiting uncommon sources of energy. While all organisms are composed of nearly identical molecules, evolution has enabled such microbes to cope with this wide range of physical and chemical conditions. Characterization of the structure and metabolic diversity of microbial communities in such extreme environments is ongoing.[167]
+
+Microbial life forms thrive even in the Mariana Trench, the deepest spot in the Earth's oceans.[155][156] Microbes also thrive inside rocks up to 1,900 feet (580 m) below the sea floor under 8,500 feet (2,600 m) of ocean.[155][157]
+
+Investigation of the tenacity and versatility of life on Earth,[166] as well as an understanding of the molecular systems that some organisms utilize to survive such extremes, is important for the search for life beyond Earth.[143] For example, lichen could survive for a month in a simulated Martian environment.[168][169]
+
+All life forms require certain core chemical elements needed for biochemical functioning. These include carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur—the elemental macronutrients for all organisms[170]—often represented by the acronym CHNOPS. Together these make up nucleic acids, proteins and lipids, the bulk of living matter. Five of these six elements comprise the chemical components of DNA, the exception being sulfur. The latter is a component of the amino acids cysteine and methionine. The most biologically abundant of these elements is carbon, which has the desirable attribute of forming multiple, stable covalent bonds. This allows carbon-based (organic) molecules to form an immense variety of chemical arrangements.[171] Alternative hypothetical types of biochemistry have been proposed that eliminate one or more of these elements, swap out an element for one not on the list, or change required chiralities or other chemical properties.[172][173]
+
+Deoxyribonucleic acid is a molecule that carries most of the genetic instructions used in the growth, development, functioning and reproduction of all known living organisms and many viruses. DNA and RNA are nucleic acids; alongside proteins and complex carbohydrates, they are one of the three major types of macromolecule that are essential for all known forms of life. Most DNA molecules consist of two biopolymer strands coiled around each other to form a double helix. The two DNA strands are known as polynucleotides since they are composed of simpler units called nucleotides.[174] Each nucleotide is composed of a nitrogen-containing nucleobase—either cytosine (C), guanine (G), adenine (A), or thymine (T)—as well as a sugar called deoxyribose and a phosphate group. The nucleotides are joined to one another in a chain by covalent bonds between the sugar of one nucleotide and the phosphate of the next, resulting in an alternating sugar-phosphate backbone. According to base pairing rules (A with T, and C with G), hydrogen bonds bind the nitrogenous bases of the two separate polynucleotide strands to make double-stranded DNA. The total amount of related DNA base pairs on Earth is estimated at 5.0 x 1037, and weighs 50 billion tonnes.[119] In comparison, the total mass of the biosphere has been estimated to be as much as 4 TtC (trillion tons of carbon).[120]
+
+DNA stores biological information. The DNA backbone is resistant to cleavage, and both strands of the double-stranded structure store the same biological information. Biological information is replicated as the two strands are separated. A significant portion of DNA (more than 98% for humans) is non-coding, meaning that these sections do not serve as patterns for protein sequences.
+
+The two strands of DNA run in opposite directions to each other and are therefore anti-parallel. Attached to each sugar is one of four types of nucleobases (informally, bases). It is the sequence of these four nucleobases along the backbone that encodes biological information. Under the genetic code, RNA strands are translated to specify the sequence of amino acids within proteins. These RNA strands are initially created using DNA strands as a template in a process called transcription.
+
+Within cells, DNA is organized into long structures called chromosomes. During cell division these chromosomes are duplicated in the process of DNA replication, providing each cell its own complete set of chromosomes. Eukaryotic organisms (animals, plants, fungi, and protists) store most of their DNA inside the cell nucleus and some of their DNA in organelles, such as mitochondria or chloroplasts.[175] In contrast, prokaryotes (bacteria and archaea) store their DNA only in the cytoplasm. Within the chromosomes, chromatin proteins such as histones compact and organize DNA. These compact structures guide the interactions between DNA and other proteins, helping control which parts of the DNA are transcribed.
+
+DNA was first isolated by Friedrich Miescher in 1869.[176] Its molecular structure was identified by James Watson and Francis Crick in 1953, whose model-building efforts were guided by X-ray diffraction data acquired by Rosalind Franklin.[177]
+
+The first known attempt to classify organisms was conducted by the Greek philosopher Aristotle (384–322 BC), who classified all living organisms known at that time as either a plant or an animal, based mainly on their ability to move. He also distinguished animals with blood from animals without blood (or at least without red blood), which can be compared with the concepts of vertebrates and invertebrates respectively, and divided the blooded animals into five groups: viviparous quadrupeds (mammals), oviparous quadrupeds (reptiles and amphibians), birds, fishes and whales. The bloodless animals were also divided into five groups: cephalopods, crustaceans, insects (which included the spiders, scorpions, and centipedes, in addition to what we define as insects today), shelled animals (such as most molluscs and echinoderms), and "zoophytes" (animals that resemble plants). Though Aristotle's work in zoology was not without errors, it was the grandest biological synthesis of the time and remained the ultimate authority for many centuries after his death.[178]
+
+The exploration of the Americas revealed large numbers of new plants and animals that needed descriptions and classification. In the latter part of the 16th century and the beginning of the 17th, careful study of animals commenced and was gradually extended until it formed a sufficient body of knowledge to serve as an anatomical basis for classification.
+
+In the late 1740s, Carl Linnaeus introduced his system of binomial nomenclature for the classification of species. Linnaeus attempted to improve the composition and reduce the length of the previously used many-worded names by abolishing unnecessary rhetoric, introducing new descriptive terms and precisely defining their meaning.[179] The Linnaean classification has eight levels: domains, kingdoms, phyla, class, order, family, genus, and species.
+
+The fungi were originally treated as plants. For a short period Linnaeus had classified them in the taxon Vermes in Animalia, but later placed them back in Plantae. Copeland classified the Fungi in his Protoctista, thus partially avoiding the problem but acknowledging their special status.[180] The problem was eventually solved by Whittaker, when he gave them their own kingdom in his five-kingdom system. Evolutionary history shows that the fungi are more closely related to animals than to plants.[181]
+
+As new discoveries enabled detailed study of cells and microorganisms, new groups of life were revealed, and the fields of cell biology and microbiology were created. These new organisms were originally described separately in protozoa as animals and protophyta/thallophyta as plants, but were united by Haeckel in the kingdom Protista; later, the prokaryotes were split off in the kingdom Monera, which would eventually be divided into two separate groups, the Bacteria and the Archaea. This led to the six-kingdom system and eventually to the current three-domain system, which is based on evolutionary relationships.[182] However, the classification of eukaryotes, especially of protists, is still controversial.[183]
+
+As microbiology, molecular biology and virology developed, non-cellular reproducing agents were discovered, such as viruses and viroids. Whether these are considered alive has been a matter of debate; viruses lack characteristics of life such as cell membranes, metabolism and the ability to grow or respond to their environments. Viruses can still be classed into "species" based on their biology and genetics, but many aspects of such a classification remain controversial.[184]
+
+In May 2016, scientists reported that 1 trillion species are estimated to be on Earth currently with only one-thousandth of one percent described.[117]
+
+The original Linnaean system has been modified over time as follows:
+
+In the 1960s cladistics emerged: a system arranging taxa based on clades in an evolutionary or phylogenetic tree.[192]
+
+Cells are the basic unit of structure in every living thing, and all cells arise from pre-existing cells by division. Cell theory was formulated by Henri Dutrochet, Theodor Schwann, Rudolf Virchow and others during the early nineteenth century, and subsequently became widely accepted.[193] The activity of an organism depends on the total activity of its cells, with energy flow occurring within and between them.[194] Cells contain hereditary information that is carried forward as a genetic code during cell division.[195]
+
+There are two primary types of cells. Prokaryotes lack a nucleus and other membrane-bound organelles, although they have circular DNA and ribosomes. Bacteria and Archaea are two domains of prokaryotes. The other primary type of cells are the eukaryotes, which have distinct nuclei bound by a nuclear membrane and membrane-bound organelles, including mitochondria, chloroplasts, lysosomes, rough and smooth endoplasmic reticulum, and vacuoles. In addition, they possess organized chromosomes that store genetic material. All species of large complex organisms are eukaryotes, including animals, plants and fungi, though most species of eukaryote are protist microorganisms.[196] The conventional model is that eukaryotes evolved from prokaryotes, with the main organelles of the eukaryotes forming through endosymbiosis between bacteria and the progenitor eukaryotic cell.[197]
+
+The molecular mechanisms of cell biology are based on proteins. Most of these are synthesized by the ribosomes through an enzyme-catalyzed process called protein biosynthesis. A sequence of amino acids is assembled and joined together based upon gene expression of the cell's nucleic acid.[198] In eukaryotic cells, these proteins may then be transported and processed through the Golgi apparatus in preparation for dispatch to their destination.[199]
+
+Cells reproduce through a process of cell division in which the parent cell divides into two or more daughter cells. For prokaryotes, cell division occurs through a process of fission in which the DNA is replicated, then the two copies are attached to parts of the cell membrane. In eukaryotes, a more complex process of mitosis is followed. However, the end result is the same; the resulting cell copies are identical to each other and to the original cell (except for mutations), and both are capable of further division following an interphase period.[200]
+
+Multicellular organisms may have first evolved through the formation of colonies of identical cells. These cells can form group organisms through cell adhesion. The individual members of a colony are capable of surviving on their own, whereas the members of a true multi-cellular organism have developed specializations, making them dependent on the remainder of the organism for survival. Such organisms are formed clonally or from a single germ cell that is capable of forming the various specialized cells that form the adult organism. This specialization allows multicellular organisms to exploit resources more efficiently than single cells.[201] In January 2016, scientists reported that, about 800 million years ago, a minor genetic change in a single molecule, called GK-PID, may have allowed organisms to go from a single cell organism to one of many cells.[202]
+
+Cells have evolved methods to perceive and respond to their microenvironment, thereby enhancing their adaptability. Cell signaling coordinates cellular activities, and hence governs the basic functions of multicellular organisms. Signaling between cells can occur through direct cell contact using juxtacrine signalling, or indirectly through the exchange of agents as in the endocrine system. In more complex organisms, coordination of activities can occur through a dedicated nervous system.[203]
+
+Though life is confirmed only on Earth, many think that extraterrestrial life is not only plausible, but probable or inevitable.[204][205] Other planets and moons in the Solar System and other planetary systems are being examined for evidence of having once supported simple life, and projects such as SETI are trying to detect radio transmissions from possible alien civilizations. Other locations within the Solar System that may host microbial life include the subsurface of Mars, the upper atmosphere of Venus,[206] and subsurface oceans on some of the moons of the giant planets.[207][208]
+Beyond the Solar System, the region around another main-sequence star that could support Earth-like life on an Earth-like planet is known as the habitable zone. The inner and outer radii of this zone vary with the luminosity of the star, as does the time interval during which the zone survives. Stars more massive than the Sun have a larger habitable zone, but remain on the Sun-like "main sequence" of stellar evolution for a shorter time interval. Small red dwarfs have the opposite problem, with a smaller habitable zone that is subject to higher levels of magnetic activity and the effects of tidal locking from close orbits. Hence, stars in the intermediate mass range such as the Sun may have a greater likelihood for Earth-like life to develop.[209] The location of the star within a galaxy may also affect the likelihood of life forming. Stars in regions with a greater abundance of heavier elements that can form planets, in combination with a low rate of potentially habitat-damaging supernova events, are predicted to have a higher probability of hosting planets with complex life.[210] The variables of the Drake equation are used to discuss the conditions in planetary systems where civilization is most likely to exist.[211] Use of the equation to predict the amount of extraterrestrial life, however, is difficult; because many of the variables are unknown, the equation functions as more of a mirror to what its user already thinks. As a result, the number of civilizations in the galaxy can be estimated as low as 9.1 x 10−13, suggesting a minimum value of 1, or as high as 15.6 million (0.156 x 109); for the calculations, see Drake equation.
+
+Artificial life is the simulation of any aspect of life, as through computers, robotics, or biochemistry.[212] The study of artificial life imitates traditional biology by recreating some aspects of biological phenomena. Scientists study the logic of living systems by creating artificial environments—seeking to understand the complex information processing that defines such systems.[194] While life is, by definition, alive, artificial life is generally referred to as data confined to a digital environment and existence.
+
+Synthetic biology is a new area of biotechnology that combines science and biological engineering. The common goal is the design and construction of new biological functions and systems not found in nature. Synthetic biology includes the broad redefinition and expansion of biotechnology, with the ultimate goals of being able to design and build engineered biological systems that process information, manipulate chemicals, fabricate materials and structures, produce energy, provide food, and maintain and enhance human health and the environment.[213]
+
+Death is the permanent termination of all vital functions or life processes in an organism or cell.[214][215] It can occur as a result of an accident, medical conditions, biological interaction, malnutrition, poisoning, senescence, or suicide. After death, the remains of an organism re-enter the biogeochemical cycle. Organisms may be consumed by a predator or a scavenger and leftover organic material may then be further decomposed by detritivores, organisms that recycle detritus, returning it to the environment for reuse in the food chain.
+
+One of the challenges in defining death is in distinguishing it from life. Death would seem to refer to either the moment life ends, or when the state that follows life begins.[215] However, determining when death has occurred is difficult, as cessation of life functions is often not simultaneous across organ systems.[216] Such determination therefore requires drawing conceptual lines between life and death. This is problematic, however, because there is little consensus over how to define life. The nature of death has for millennia been a central concern of the world's religious traditions and of philosophical inquiry. Many religions maintain faith in either a kind of afterlife or reincarnation for the soul, or resurrection of the body at a later date.
+
+Extinction is the process by which a group of taxa or species dies out, reducing biodiversity.[217] The moment of extinction is generally considered the death of the last individual of that species. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively after a period of apparent absence. Species become extinct when they are no longer able to survive in changing habitat or against superior competition. In Earth's history, over 99% of all the species that have ever lived are extinct;[218][112][113][114] however, mass extinctions may have accelerated evolution by providing opportunities for new groups of organisms to diversify.[219]
+
+Fossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossil-containing rock formations and sedimentary layers (strata) is known as the fossil record. A preserved specimen is called a fossil if it is older than the arbitrary date of 10,000 years ago.[220] Hence, fossils range in age from the youngest at the start of the Holocene Epoch to the oldest from the Archaean Eon, up to 3.4 billion years old.[221][222]

en/602.html.txt

@@ -0,0 +1,105 @@
+
+
+Comics is a medium used to express narratives or other ideas through images, usually combined with text. It typically takes the form of a sequence of panels of images. Textual devices such as speech balloons, captions, and onomatopoeia can indicate dialogue, narration, sound effects, or other information. The size and arrangement of panels contribute to narrative pacing. Cartooning and other forms of illustration are the most common image-making means in comics; fumetti is a form which uses photographic images. Common forms include comic strips, editorial and gag cartoons, and comic books. Since the late 20th century, bound volumes such as graphic novels, comic albums, and tankōbon have become increasingly common, while online webcomics have proliferated in the 21st century.
+
+The history of comics has followed different paths in different cultures. Scholars have posited a pre-history as far back as the Lascaux cave paintings in France. By the mid-20th century, comics flourished, particularly in the United States, western Europe (especially France and Belgium), and Japan. The history of European comics is often traced to Rodolphe Töpffer's cartoon strips of the 1830s, but the medium truly became popular in the 1930s following the success of strips and books such as The Adventures of Tintin.  American comics emerged as a mass medium in the early 20th century with the advent of newspaper comic strips; magazine-style comic books followed in the 1930s, in which the superhero genre became prominent after Superman appeared in 1938. Histories of Japanese comics and cartooning (manga) propose origins as early as the 12th century. Modern comic strips emerged in Japan in the early 20th century, and the output of comics magazines and books rapidly expanded in the post-World War II era (1945–) with the popularity of cartoonists such as Osamu Tezuka (Astro Boy, et al.). Comics has had a lowbrow reputation for much of its history, but towards the end of the 20th century began to find greater acceptance with the public and academics.
+
+The term comics is used as a singular noun when it refers to the medium itself (e.g. "Comics is a visual art form"), but becomes plural when referring to works collectively (e.g. "Comics are popular reading material"). Though the term derives from the humorous (comic) work that predominated in early American newspaper comic strips, it has become standard for non-humorous works too. The alternate spelling comix – coined by the underground comix movement – is sometimes used to address these ambiguities.[1] In English, it is common to refer to the comics of different cultures by the terms used in their original languages, such as manga for Japanese comics, or bandes dessinées/B.D. for French-language comics.
+
+There is no consensus among theorists and historians on a definition of comics; some emphasize the combination of images and text, some sequentiality or other image relations, and others historical aspects, such as mass reproduction or the use of recurring characters. Increasing cross-pollination of concepts from different comics cultures and eras has only made definition more difficult.
+
+MangaHokusai, early 19th century
+
+Histoire de Monsieur CryptogameRodolphe Töpffer, 1830
+
+Ally Sloper in Some of the Mysteries of Loan and DiscountCharles Henry Ross, 1867
+
+The Yellow KidR.F. Outcault, 1898
+
+The European, American, and Japanese comics traditions have followed different paths.[2]  Europeans have seen their tradition as beginning with the Swiss Rodolphe Töpffer from as early as 1827 and Americans have seen the origin of theirs in Richard F. Outcault's 1890s newspaper strip The Yellow Kid, though many Americans have come to recognize Töpffer's precedence.[3]  Japan has a long history of satirical cartoons and comics leading up to the World War II era.  The ukiyo-e artist Hokusai popularized the Japanese term for comics and cartooning, manga, in the early 19th century.[4]  In the 1930s Harry "A" Chesler started a comics studio, which eventually at its height employed 40 artists working for 50 different publishers who helped make the comics medium flourish in "the Golden Age of Comics" after World War II.[5] In the post-war era modern Japanese comics began to flourish when Osamu Tezuka produced a prolific body of work.[6]Towards the close of the 20th century, these three traditions converged in a trend towards book-length comics: the comic album in Europe, the tankōbon[a] in Japan, and the graphic novel in the English-speaking countries.[2]
+
+Outside of these genealogies, comics theorists and historians have seen precedents for comics in the Lascaux cave paintings[7] in France (some of which appear to be chronological sequences of images), Egyptian hieroglyphs, Trajan's Column in Rome,[8] the 11th-century Norman Bayeux Tapestry,[9] the 1370 bois Protat woodcut, the 15th-century Ars moriendi and block books, Michelangelo's The Last Judgment in the Sistine Chapel,[8] and William Hogarth's 18th-century sequential engravings,[10] amongst others.[8][b]
+
+Illustrated humour periodicals were popular in 19th-century Britain, the earliest of which was the short-lived The Glasgow Looking Glass in 1825.  The most popular was Punch,[12] which popularized the term cartoon for its humorous caricatures.[13]  On occasion the cartoons in these magazines appeared in sequences;[12] the character Ally Sloper featured in the earliest serialized comic strip when the character began to feature in its own weekly magazine in 1884.[14]
+
+American comics developed out of such magazines as Puck, Judge, and Life.  The success of illustrated humour supplements in the New York World and later the New York American, particularly Outcault's The Yellow Kid, led to the development of newspaper comic strips.  Early Sunday strips were full-page[15] and often in colour.  Between 1896 and 1901 cartoonists experimented with sequentiality, movement, and speech balloons.[16] A northworthy example is  Gustave Verbeek, who wrote his comic series "The UpsideDowns of Old Man Muffaroo and Little Lady Lovekins" between 1903 and 1905. These comics were made in such a way that one could read the 6 panel comic, flip the book and keep reading. He made 64 such comics in total. In 2012 a remake of a selection of the comics was made by Marcus Ivarsson in the book 'In Uppåner med Lilla Lisen & Gamle Muppen'. (ISBN 978-91-7089-524-1)
+
+
+
+Shorter, black-and-white daily strips began to appear early in the 20th century, and became established in newspapers after the success in 1907 of Bud Fisher's Mutt and Jeff.[17] In Britain, the Amalgamated Press established a popular style of a sequence of images with text beneath them, including Illustrated Chips and Comic Cuts.[18] Humour strips predominated at first, and in the 1920s and 1930s strips with continuing stories in genres such as adventure and drama also became popular.[17]
+
+Thin periodicals called comic books appeared in the 1930s, at first reprinting newspaper comic strips; by the end of the decade, original content began to dominate.[19]  The success in 1938 of Action Comics and its lead hero Superman marked the beginning of the Golden Age of Comic Books, in which the superhero genre was prominent.[20] In the UK and the Commonwealth, the DC Thomson-created Dandy (1937) and Beano (1938) became successful humor-based titles, with a combined circulation of over 2 million copies by the 1950s. Their characters, including "Dennis the Menace", "Desperate Dan" and "The Bash Street Kids" have been read by generations of British schoolboys.[21] The comics originally experimented with superheroes and action stories before settling on humorous strips featuring a mix of the Amalgamated Press and US comic book styles.[22]
+
+The popularity of superhero comic books declined following World War II,[23] while comic book sales continued to increase as other genres proliferated, such as romance, westerns, crime, horror, and humour.[24]  Following a sales peak in the early 1950s, the content of comic books (particularly crime and horror) was subjected to scrutiny from parent groups and government agencies, which culminated in Senate hearings that led to the establishment of the Comics Code Authority self-censoring body.[25]  The Code has been blamed for stunting the growth of American comics and maintaining its low status in American society for much of the remainder of the century.[26]  Superheroes re-established themselves as the most prominent comic book genre by the early 1960s.[27] Underground comix challenged the Code and readers with adult, countercultural content in the late 1960s and early 1970s.[28]  The underground gave birth to the alternative comics movement in the 1980s and its mature, often experimental content in non-superhero genres.[29]
+
+Comics in the US has had a lowbrow reputation stemming from its roots in mass culture; cultural elites sometimes saw popular culture as threatening culture and society.  In the latter half of the 20th century, popular culture won greater acceptance, and the lines between high and low culture began to blur.  Comics nevertheless continued to be stigmatized, as the medium was seen as entertainment for children and illiterates.[30]
+
+The graphic novel—book-length comics—began to gain attention after Will Eisner popularized the term with his book A Contract with God (1978).[31]  The term became widely known with the public after the commercial success of Maus, Watchmen, and The Dark Knight Returns in the mid-1980s.[32]  In the 21st century graphic novels became established in mainstream bookstores[33] and libraries[34] and webcomics became common.[35]
+
+The francophone Swiss Rodolphe Töpffer produced comic strips beginning in 1827,[8] and published theories behind the form.[36]  Cartoons appeared widely in newspapers and magazines from the 19th century.[37]  The success of Zig et Puce in 1925 popularized the use of speech balloons in European comics, after which Franco-Belgian comics began to dominate.[38] The Adventures of Tintin, with its signature clear line style,[39] was first serialized in newspaper comics supplements beginning in 1929,[40] and became an icon of Franco-Belgian comics.[41]
+
+Following the success of Le Journal de Mickey (1934–44),[42] dedicated comics magazines[43] and full-colour comic albums became the primary outlet for comics in the mid-20th century.[44]  As in the US, at the time comics were seen as infantile and a threat to culture and literacy; commentators stated that "none bear up to the slightest serious analysis",[c] and that comics were "the sabotage of all art and all literature".[46][d]
+
+In the 1960s, the term bandes dessinées ("drawn strips") came into wide use in French to denote the medium.[47]  Cartoonists began creating comics for mature audiences,[48] and the term "Ninth Art"[e] was coined, as comics began to attract public and academic attention as an artform.[49]  A group including René Goscinny and Albert Uderzo founded the magazine Pilote in 1959 to give artists greater freedom over their work.  Goscinny and Uderzo's The Adventures of Asterix appeared in it[50] and went on to become the best-selling French-language comics series.[51]  From 1960, the satirical and taboo-breaking Hara-Kiri defied censorship laws in the countercultural spirit that led to the May 1968 events.[52]
+
+Frustration with censorship and editorial interference led to a group of Pilote cartoonists to found the adults-only L'Écho des savanes in 1972.  Adult-oriented and experimental comics flourished in the 1970s, such as in the experimental science fiction of Mœbius and others in Métal hurlant, even mainstream publishers took to publishing prestige-format adult comics.[53]
+
+From the 1980s, mainstream sensibilities were reasserted and serialization became less common as the number of comics magazines decreased and many comics began to be published directly as albums.[54]  Smaller publishers such as L'Association[55] that published longer works[56] in non-traditional formats[57] by auteur-istic creators also became common.  Since the 1990s, mergers resulted in fewer large publishers, while smaller publishers proliferated.  Sales overall continued to grow despite the trend towards a shrinking print market.[58]
+
+Japanese comics and cartooning (manga),[g] have a history that has been seen as far back as the anthropomorphic characters in the 12th-to-13th-century Chōjū-jinbutsu-giga, 17th-century toba-e and kibyōshi picture books,[62] and woodblock prints such as ukiyo-e which were popular between the 17th and 20th centuries.  The kibyōshi contained examples of sequential images, movement lines,[63] and sound effects.[64]
+
+Illustrated magazines for Western expatriates introduced Western-style satirical cartoons to Japan in the late 19th century.  New publications in both the Western and Japanese styles became popular, and at the end of the 1890s, American-style newspaper comics supplements began to appear in Japan,[65] as well as some American comic strips.[62]  1900 saw the debut of the Jiji Manga in the Jiji Shinpō newspaper—the first use of the word "manga" in its modern sense,[61] and where, in 1902, Rakuten Kitazawa began the first modern Japanese comic strip.[66]  By the 1930s, comic strips were serialized in large-circulation monthly girls' and boys' magazine and collected into hardback volumes.[67]
+
+The modern era of comics in Japan began after World War II, propelled by the success of the serialized comics of the prolific Osamu Tezuka[68] and the comic strip Sazae-san.[69]  Genres and audiences diversified over the following decades.  Stories are usually first serialized in magazines which are often hundreds of pages thick and may contain over a dozen stories;[70] they are later compiled in tankōbon-format books.[71]  At the turn of the 20th and 21st centuries, nearly a quarter of all printed material in Japan was comics.[72] Translations became extremely popular in foreign markets—in some cases equaling or surpassing the sales of domestic comics.[73]
+
+Comic strips are generally short, multipanel comics that traditionally most commonly appeared in newspapers.  In the US, daily strips have normally occupied a single tier, while Sunday strips have been given multiple tiers.  In the early 20th century, daily strips were typically in black-and-white and Sundays were usually in colour and often occupied a full page.[74]
+
+Specialized comics periodicals formats vary greatly in different cultures.  Comic books, primarily an American format, are thin periodicals[75] usually published in colour.[76]  European and Japanese comics are frequently serialized in magazines—monthly or weekly in Europe,[61] and usually black-and-white and weekly in Japan.[77]  Japanese comics magazine typically run to hundreds of pages.[78]
+
+Book-length comics take different forms in different cultures. European comic albums are most commonly printed in A4-size[79] colour volumes.[44] In English-speaking countries, the trade paperback format originating from collected comic books have also been chosen for original material. Otherwise, bound volumes of comics are called graphic novels and are available in various formats. Despite incorporating the term "novel"—a term normally associated with fiction—"graphic novel" also refers to non-fiction and collections of short works.[80]  Japanese comics are collected in volumes called tankōbon following magazine serialization.[81]
+
+Gag and editorial cartoons usually consist of a single panel, often incorporating a caption or speech balloon.  Definitions of comics which emphasize sequence usually exclude gag, editorial, and other single-panel cartoons; they can be included in definitions that emphasize the combination of word and image.[82]  Gag cartoons first began to proliferate in broadsheets published in Europe in the 18th and 19th centuries, and the term "cartoon"[h] was first used to describe them in 1843 in the British humour magazine Punch.[13]
+
+Webcomics are comics that are available on the internet.  They are able to reach large audiences, and new readers usually can access archived installments.[83]  Webcomics can make use of an infinite canvas—meaning they are not constrained by size or dimensions of a page.[84]
+
+Some consider storyboards[85] and wordless novels to be comics.[86]  Film studios, especially in animation, often use sequences of images as guides for film sequences.  These storyboards are not intended as an end product and are rarely seen by the public.[85]  Wordless novels are books which use sequences of captionless images to deliver a narrative.[87]
+
+While almost all comics art is in some sense abbreviated, and also while every artist who has produced comics work brings their own individual approach to bear, some broader art styles have been identified. Comic strip artists Cliff Sterrett, Frank King, and Gus Arriola often used unusual, colorful backgrounds, sometimes veering into abstract art.
+
+The basic styles have been identified as realistic and cartoony, with a huge middle ground for which R. Fiore has coined the phrase liberal. Fiore has also expressed distaste with the terms realistic and cartoony, preferring the terms literal and freestyle, respectively.[88]
+
+Scott McCloud has created "The Big Triangle"[89] as a tool for thinking about comics art. He places the realistic representation in the bottom left corner, with iconic representation, or cartoony art, in the bottom right, and a third identifier, abstraction of image, at the apex of the triangle. This allows placement and grouping of artists by triangulation.
+
+McCloud also notes that in several traditions, there is a tendency to have the main characters drawn rather simplistic and cartoony, while the backgrounds and environment are depicted realistically. Thus, he argues, the reader easily identifies with the characters, (as they are similar to one's idea of self), whilst being immersed into a world, that's three-dimensional and textured.[91]  Good examples of this phenomenon include Hergé's The Adventures of Tintin (in his "personal trademark" Ligne claire style), Will Eisner's Spirit and Osamu Tezuka's Buddha, among many others.
+
+R. C. Harvey, 2001[82]
+
+Similar to the problems of defining literature and film,[92] no consensus has been reached on a definition of the comics medium,[93] and attempted definitions and descriptions have fallen prey to numerous exceptions.[94]  Theorists such as Töpffer,[95] R.C. Harvey, Will Eisner,[96] David Carrier,[97] Alain Rey,[93] and Lawrence Grove emphasize the combination of text and images,[98] though there are prominent examples of pantomime comics throughout its history.[94]  Other critics, such as Thierry Groensteen[98] and Scott McCloud, have emphasized the primacy of sequences of images.[99]  Towards the close of the 20th century, different cultures' discoveries of each other's comics traditions, the rediscovery of forgotten early comics forms, and the rise of new forms made defining comics a more complicated task.[100]
+
+European comics studies began with Töpffer's theories of his own work in the 1840s, which emphasized panel transitions and the visual–verbal combination.  No further progress was made until the 1970s.[101]  Pierre Fresnault-Deruelle then took a semiotics approach to the study of comics, analyzing text–image relations, page-level image relations, and image discontinuities, or what Scott McCloud later dubbed "closure".[102]  In 1987, Henri Vanlier introduced the term multicadre, or "multiframe", to refer to the comics page as a semantic unit.[103]  By the 1990s, theorists such as Benoît Peeters and Thierry Groensteen turned attention to artists' poïetic creative choices.[102] Thierry Smolderen and Harry Morgan have held relativistic views of the definition of comics, a medium that has taken various, equally valid forms over its history.  Morgan sees comics as a subset of "les littératures dessinées" (or "drawn literatures").[100]  French theory has come to give special attention to the page, in distinction from American theories such as McCloud's which focus on panel-to-panel transitions.[103] Since the mid-2000s, Neil Cohn has begun analyzing how comics are understood using tools from cognitive science, extending beyond theory by using actual psychological and neuroscience experiments. This work has argued that sequential images and page layouts both use separate rule-bound "grammars" to be understood that extend beyond panel-to-panel transitions and categorical distinctions of types of layouts, and that the brain's comprehension of comics is similar to comprehending other domains, such as language and music.[104]
+
+Historical narratives of manga tend to focus either on its recent, post-WWII history, or on attempts to demonstrate deep roots in the past, such as to the Chōjū-jinbutsu-giga picture scroll of the 12th and 13th centuries, or the early 19th-century Hokusai Manga.[105]  The first historical overview of Japanese comics was Seiki Hosokibara's Nihon Manga-Shi[i] in 1924.[106]  Early post-war Japanese criticism was mostly of a left-wing political nature until the 1986 publication of Tomofusa Kure's Modern Manga: The Complete Picture,[j] which de-emphasized politics in favour of formal aspects, such as structure and a "grammar" of comics.  The field of manga studies increased rapidly, with numerous books on the subject appearing in the 1990s.[107]  Formal theories of manga have focused on developing a "manga expression theory",[k] with emphasis on spatial relationships in the structure of images on the page, distinguishing the medium from film or literature, in which the flow of time is the basic organizing element.[108]  Comics studies courses have proliferated at Japanese universities, and Japan Society for Studies in Cartoon and Comics [ja][l] was established in 2001 to promote comics scholarship.[109]  The publication of Frederik L. Schodt's Manga! Manga! The World of Japanese Comics in 1983 led to the spread of use of the word manga outside Japan to mean "Japanese comics" or "Japanese-style comics".[110]
+
+Coulton Waugh attempted the first comprehensive history of American comics with The Comics (1947).[111]  Will Eisner's Comics and Sequential Art (1985) and Scott McCloud's Understanding Comics (1993) were early attempts in English to formalize the study of comics.  David Carrier's The Aesthetics of Comics (2000) was the first full-length treatment of comics from a philosophical perspective.[112]  Prominent American attempts at definitions of comics include Eisner's, McCloud's, and Harvey's.  Eisner described what he called "sequential art" as "the arrangement of pictures or images and words to narrate a story or dramatize an idea";[113]  Scott McCloud defined comics as "juxtaposed pictorial and other images in deliberate sequence, intended to convey information and/or to produce an aesthetic response in the viewer",[114] a strictly formal definition which detached comics from its historical and cultural trappings.[115]  R.C. Harvey defined comics as "pictorial narratives or expositions in which words (often lettered into the picture area within speech balloons) usually contribute to the meaning of the pictures and vice versa".[116]  Each definition has had its detractors.  Harvey saw McCloud's definition as excluding single-panel cartoons,[117]  and objected to McCloud's de-emphasizing verbal elements, insisting "the essential characteristic of comics is the incorporation of verbal content".[103]  Aaron Meskin saw McCloud's theories as an artificial attempt to legitimize the place of comics in art history.[96]
+
+Cross-cultural study of comics is complicated by the great difference in meaning and scope of the words for "comics" in different languages.[118]  The French term for comics, bandes dessinées ("drawn strip") emphasizes the juxtaposition of drawn images as a defining factor,[119] which can imply the exclusion of even photographic comics.[120]  The term manga is used in Japanese to indicate all forms of comics, cartooning,[121] and caricature.[122]
+
+The term comics refers to the comics medium when used as an uncountable noun and thus takes the singular: "comics is a medium" rather than "comics are a medium".  When comic appears as a countable noun it refers to instances of the medium, such as individual comic strips or comic books: "Tom's comics are in the basement."[123]
+
+Panels are individual images containing a segment of action,[124] often surrounded by a border.[125]  Prime moments in a narrative are broken down into panels via a process called encapsulation.[126]  The reader puts the pieces together via the process of closure by using background knowledge and an understanding of panel relations to combine panels mentally into events.[127]  The size, shape, and arrangement of panels each affect the timing and pacing of the narrative.[128]  The contents of a panel may be asynchronous, with events depicted in the same image not necessarily occurring at the same time.[129]
+
+Text is frequently incorporated into comics via speech balloons, captions, and sound effects.  Speech balloons indicate dialogue (or thought, in the case of thought balloons), with tails pointing at their respective speakers.[130]  Captions can give voice to a narrator, convey characters' dialogue or thoughts,[131] or indicate place or time.[132]  Speech balloons themselves are strongly associated with comics, such that the addition of one to an image is sufficient to turn the image into comics.[133]  Sound effects mimic non-vocal sounds textually using onomatopoeia sound-words.[134]
+
+Cartooning is most frequently used in making comics, traditionally using ink (especially India ink) with dip pens or ink brushes;[135] mixed media and digital technology have become common.  Cartooning techniques such as motion lines[136] and abstract symbols are often employed.[137]
+
+While comics are often the work of a single creator, the labour of making them is frequently divided between a number of specialists.  There may be separate writers and artists, and artists may specialize in parts of the artwork such as characters or backgrounds, as is common in Japan.[138]  Particularly in American superhero comic books,[139] the art may be divided between a penciller, who lays out the artwork in pencil;[140] an inker, who finishes the artwork in ink;[141] a colourist;[142] and a letterer, who adds the captions and speech balloons.[143]
+
+The English-language term comics derives from the humorous (or "comic") work which predominated in early American newspaper comic strips; usage of the term has become standard for non-humorous works as well.  The term "comic book" has a similarly confusing history: they are most often not humorous; nor are they regular books, but rather periodicals.[144]  It is common in English to refer to the comics of different cultures by the terms used in their original languages, such as manga for Japanese comics, or bandes dessinées for French-language Franco-Belgian comics.[145]
+
+Many cultures have taken their words for comics from English, including Russian (Комикс, komiks)[146] and German (comic).[147]  Similarly, the Chinese term manhua[148] and the Korean manhwa[149] derive from the Chinese characters with which the Japanese term manga is written.[150]
+
+Academic journals
+
+Archives
+
+Databases

en/6021.html.txt

@@ -0,0 +1,369 @@
+
+
+Vladimir Vladimirovich Putin (/ˈpuːtɪn/; Russian: Влади́мир Влади́мирович Пу́тин [vɫɐˈdʲimʲɪr vɫɐˈdʲimʲɪrəvʲɪtɕ ˈputʲɪn] (listen); born 7 October 1952) is a Russian politician and former intelligence officer who has served as President of Russia since 2012, previously holding the position from 1999 until 2008.[c][5][6][7] He was also the Prime Minister of Russia from 1999 to 2000 and again from 2008 to 2012.
+
+Putin was born in Leningrad (now Saint Petersburg) and studied law at Leningrad State University, graduating in 1975. Putin worked as a KGB foreign intelligence officer for 16 years, rising to the rank of Lieutenant Colonel, before resigning in 1991 to begin a political career in Saint Petersburg. He later moved to Moscow in 1996 to join the administration of President Boris Yeltsin. He served as Director of the Federal Security Service (FSB) and Secretary of the Security Council, before being appointed as Prime Minister in August 1999. After the resignation of Yeltsin, Putin became Acting President, and less than four months later was elected outright to his first term as president and was reelected in 2004.
+
+During his first tenure as president, the Russian economy grew for eight straight years, with GDP measured by purchasing power increasing by 72%, real incomes increased by a factor of 2.5, real wages more than tripled; unemployment and poverty more than halved and the Russians' self-assessed life satisfaction rose significantly.[8] The growth was a result of a five-fold increase in the price of oil and gas which constitute the majority of Russian exports, recovery from the post-Communist depression and financial crises, a rise in foreign investment,[9] and prudent economic and fiscal policies.[10][11] Putin served as Prime Minister under Dmitry Medvedev from 2008 to 2012, where he oversaw large scale military reform and police reform. In 2012, Putin sought a third term as president and won with 64% of the vote.[12] Falling oil prices coupled with international sanctions imposed at the beginning of 2014 after Russia's annexation of Crimea and military intervention in Eastern Ukraine led to GDP shrinking by 3.7% in 2015, though the Russian economy rebounded in 2016 with 0.3% GDP growth, and the recession officially ended.[13][14][15][16] Development under Putin has included the construction of pipelines, the restoration of the satellite navigation system GLONASS, and the building of infrastructure for international events such as the 2014 Winter Olympics in Sochi. Putin gained 76% of the vote in the 2018 election and was re-elected for a six-year term that will end in 2024.
+
+Under Putin's leadership, Russia has experienced democratic backsliding. Experts do not generally consider Russia to be a democracy, citing jailing of political opponents, curtailed press freedom, and the lack of free and fair elections.[17][18][19][20][21]  Russia has scored poorly on Transparency International's Corruption Perceptions Index, the Economist Intelligence Unit's Democracy Index and Freedom House's Freedom in the World index (including a record low 20/100 rating in the 2017 Freedom in the World report, a rating not given since the time of the Soviet Union). Human rights organizations and activists accuse Putin of persecuting political critics and activists as well as ordering them tortured or assassinated; he has rejected accusations of human rights abuses. Officials of the United States government have accused him of leading an interference program against Hillary Clinton in support of Donald Trump during the U.S. presidential election in 2016, an allegation which both Trump and Putin have frequently denied and criticized.
+
+Vladimir Vladimirovich Putin was born on 7 October 1952 in Leningrad, Russian SFSR, Soviet Union (now Saint Petersburg),[22][23] the youngest of three children of Vladimir Spiridonovich Putin (1911–1999) and Maria Ivanovna Putina (née Shelomova; 1911–1998). Vladimir Spiridonovich's father was a cook to Vladimir Lenin.[24] Putin's birth was preceded by the deaths of two brothers, Viktor and Albert, born in the mid-1930s. Albert died in infancy and Viktor died of diphtheria during the Siege of Leningrad in World War II.[citation needed] Putin's mother was a factory worker and his father was a conscript in the Soviet Navy, serving in the submarine fleet in the early 1930s. Early in World War II, his father served in the destruction battalion of the NKVD.[25][26][27] Later, he was transferred to the regular army and was severely wounded in 1942.[28] Putin's maternal grandmother was killed by the German occupiers of Tver region in 1941, and his maternal uncles disappeared from the war front.[29]
+
+On 1 September 1960, Putin started at School No. 193 at Baskov Lane, near his home. He was one of a few in the class of approximately 45 pupils who was not yet a member of the Young Pioneer organization. At age 12, he began to practice sambo and judo. He is a Judo black belt and national master of sports in Sambo. He wished to emulate the intelligence officers portrayed in Soviet cinema.[30] Putin studied German at Saint Petersburg High School 281 and speaks German fluently.[31][32]
+
+Putin studied Law at the Leningrad State University (now Saint Petersburg State University) in 1970 and graduated in 1975.[33] His thesis was on "The Most Favored Nation Trading Principle in International Law".[34] While there, he was required to join the Communist Party of the Soviet Union and remained a member until it ceased to exist (it was outlawed in August 1991).[35] Putin met Anatoly Sobchak, an assistant professor who taught business law,[d] was co-author of the Russian constitution, and who would be influential in Putin's career.[36]
+
+In 1975, Putin joined the KGB and trained at the 401st KGB school in Okhta, Leningrad.[22][37] After training, he worked in the Second Chief Directorate (counter-intelligence), before he was transferred to the First Chief Directorate, where he monitored foreigners and consular officials in Leningrad.[22][38][39] In September 1984, Putin was sent to Moscow for further training at the Yuri Andropov Red Banner Institute.[40][41][42] From 1985 to 1990 he served in Dresden, East Germany,[43] using a cover identity as a translator.[44] Masha Gessen, a Russian-American who has authored a biography about Putin, claims "Putin and his colleagues were reduced mainly to collecting press clippings, thus contributing to the mountains of useless information produced by the KGB".[44] According to a later anonymous source cited by journalist Catherine Belton, Putin was personally involved in Soviet support for the West German terrorist Red Army Faction during this time.[45] According to Putin's official biography, during the fall of the Berlin Wall that began on 9 November 1989, he supposedly burned KGB files to prevent demonstrators from obtaining them.[46]
+
+After the collapse of the Communist East German government, Putin returned to Leningrad in early 1990, where he worked for about three months with the International Affairs section of Leningrad State University, reporting to Vice-Rector Yuriy Molchanov.[39] There, he looked for new KGB recruits, watched the student body, and renewed his friendship with his former professor, Anatoly Sobchak, soon to be the Mayor of Leningrad.[47] Putin claims that he resigned with the rank of Lieutenant Colonel on 20 August 1991,[47] on the second day of the 1991 Soviet coup d'état attempt against the Soviet President Mikhail Gorbachev.[48] Putin said: "As soon as the coup began, I immediately decided which side I was on", although he also noted that the choice was hard because he had spent the best part of his life with "the organs".[49]
+
+In 1999, Putin described communism as "a blind alley, far away from the mainstream of civilization".[50]
+
+In May 1990, Putin was appointed as an advisor on international affairs to the Mayor of Leningrad Anatoly Sobchak. In a 2017 interview with Oliver Stone, Putin said that he resigned from the KGB in 1991, following the coup against Mikhail Gorbachev, as he did not agree with what had happened and did not want to be part of the intelligence in the new administration.[52]
+
+On 28 June 1991, he became head of the Committee for External Relations of the Mayor's Office, with responsibility for promoting international relations and foreign investments[53] and registering business ventures. Within a year, Putin was investigated by the city legislative council led by Marina Salye. It was concluded that he had understated prices and permitted the export of metals valued at $93 million in exchange for foreign food aid that never arrived.[54][33] Despite the investigators' recommendation that Putin be fired, Putin remained head of the Committee for External Relations until 1996.[55][56] From 1994 to 1996, he held several other political and governmental positions in Saint Petersburg.[57]
+
+In March 1994, Putin was appointed as First Deputy Chairman of the Government of Saint Petersburg. In May 1995, he organized the Saint Petersburg branch of the pro-government Our Home – Russia political party, the liberal party of power founded by Prime Minister Viktor Chernomyrdin. In 1995, he managed the legislative election campaign for that party, and from 1995 through June 1997, he was the leader of its Saint Petersburg branch.[57]
+
+In June 1996, Sobchak lost his bid for reelection in Saint Petersburg, so Putin moved to Moscow and was appointed as Deputy Chief of the Presidential Property Management Department [ru] headed by Pavel Borodin. He occupied this position until March 1997. During his tenure, Putin was responsible for the foreign property of the state and organized the transfer of the former assets of the Soviet Union and Communist Party to the Russian Federation.[36]
+
+On 26 March 1997, President Boris Yeltsin appointed Putin deputy chief of Presidential Staff, which he remained until May 1998, and chief of the Main Control Directorate of the Presidential Property Management Department (until June 1998). His predecessor on this position was Alexei Kudrin and the successor was Nikolai Patrushev, both future prominent politicians and Putin's associates.[36]
+
+On 27 June 1997, at the Saint Petersburg Mining Institute, guided by rector Vladimir Litvinenko, Putin defended his Candidate of Science dissertation in economics, titled "The Strategic Planning of Regional Resources Under the Formation of Market Relations".[58] This exemplified the custom in Russia for a rising young official to write a scholarly work in mid-career.[59] When Putin later became president, the dissertation became a target of plagiarism accusations by fellows at the Brookings Institution; although the dissertation was referenced,[60][61] the Brookings fellows asserted that it constituted plagiarism albeit perhaps unintentional.[60] The dissertation committee denied the accusations.[61][62]
+
+On 25 May 1998, Putin was appointed First Deputy Chief of Presidential Staff for regions, replacing Viktoriya Mitina; and, on 15 July, he was appointed head of the commission for the preparation of agreements on the delimitation of power of regions and the federal center attached to the president, replacing Sergey Shakhray. After Putin's appointment, the commission completed no such agreements, although during Shakhray's term as the Head of the Commission 46 agreements were signed.[63] Later, after becoming president, Putin canceled all those agreements.[36]
+
+On 25 July 1998, Yeltsin appointed Putin as Director of the Federal Security Service (FSB), the primary intelligence and security organization of the Russian Federation and the successor to the KGB.[64]
+
+On 9 August 1999, Putin was appointed one of three First Deputy Prime Ministers, and later on that day, was appointed acting Prime Minister of the Government of the Russian Federation by President Yeltsin.[65] Yeltsin also announced that he wanted to see Putin as his successor. Later on that same day, Putin agreed to run for the presidency.[66]
+
+On 16 August, the State Duma approved his appointment as Prime Minister with 233 votes in favor (vs. 84 against, 17 abstained),[67] while a simple majority of 226 was required, making him Russia's fifth PM in fewer than eighteen months. On his appointment, few expected Putin, virtually unknown to the general public, to last any longer than his predecessors. He was initially regarded as a Yeltsin loyalist; like other prime ministers of Boris Yeltsin, Putin did not choose ministers himself, his cabinet was determined by the presidential administration.[68]
+
+Yeltsin's main opponents and would-be successors were already campaigning to replace the ailing president, and they fought hard to prevent Putin's emergence as a potential successor. Following the Russian apartment bombings, Putin's law-and-order image and unrelenting approach to the Second Chechen War against the Chechen Republic of Ichkeria soon combined to raise his popularity and allowed him to overtake his rivals.
+
+While not formally associated with any party, Putin pledged his support to the newly formed Unity Party,[69] which won the second largest percentage of the popular vote (23.3%) in the December 1999 Duma elections, and in turn supported Putin.
+
+On 31 December 1999, Yeltsin unexpectedly resigned and, according to the Constitution of Russia, Putin became Acting President of the Russian Federation. On assuming this role, Putin went on a previously scheduled visit to Russian troops in Chechnya.[70]
+
+The first Presidential Decree that Putin signed, on 31 December 1999, was titled "On guarantees for former president of the Russian Federation and members of his family".[71][72] This ensured that "corruption charges against the outgoing President and his relatives" would not be pursued.[73] This was most notably targeted at the Mabetex bribery case in which Yeltsin's family members were involved. On 30 August 2000, a criminal investigation (number 18/238278-95) was dropped in which Putin himself was one of the suspects[74][75] as a member of the Saint Petersburg city government. On 30 December 2000, yet another case against the prosecutor general was dropped "for lack of evidence", in spite of thousands of documents passed by Swiss prosecution.[76] On 12 February 2001, Putin signed a similar federal law which replaced the decree of 1999. A case regarding Putin's alleged corruption in metal exports from 1992 was brought back by Marina Salye, but she was silenced and forced to leave Saint Petersburg.[77]
+
+While his opponents had been preparing for an election in June 2000, Yeltsin's resignation resulted in the presidential elections being held within three months, on 26 March 2000; Putin won in the first round with 53% of the vote.[78]
+
+The inauguration of President Putin occurred on 7 May 2000. Putin appointed the Minister of Finance, Mikhail Kasyanov, as the Prime Minister.
+
+The first major challenge to Putin's popularity came in August 2000, when he was criticized for the alleged mishandling of the Kursk submarine disaster.[79] That criticism was largely because it was several days before Putin returned from vacation, and several more before he visited the scene.[79]
+
+Between 2000 and 2004, Putin set about the reconstruction of the impoverished condition of the country, apparently winning a power-struggle with the Russian oligarchs, reaching a 'grand bargain' with them. This bargain allowed the oligarchs to maintain most of their powers, in exchange for their explicit support for—and alignment with—Putin's government.[80][81]
+
+The Moscow theater hostage crisis occurred in October 2002. Many in the Russian press and in the international media warned that the deaths of 130 hostages in the special forces' rescue operation during the crisis would severely damage President Putin's popularity. However, shortly after the siege had ended, the Russian president enjoyed record public approval ratings – 83% of Russians declared themselves satisfied with Putin and his handling of the siege.[82]
+
+In 2003, a referendum was held in Chechnya, adopting a new constitution which declares that the Republic of Chechnya is a part of Russia; on the other hand, the region did acquire autonomy.[83] Chechnya has been gradually stabilized with the establishment of the Parliamentary elections and a Regional Government.[84][85] Throughout the Second Chechen War, Russia severely disabled the Chechen rebel movement; however, sporadic attacks by rebels continued to occur throughout the northern Caucasus.[86]
+
+On 14 March 2004, Putin was elected to the presidency for a second term, receiving 71% of the vote.[78] The Beslan school hostage crisis took place in September 2004; more than 330 people died, including 186 children.[90]
+
+The near 10-year period prior to the rise of Putin after the dissolution of Soviet rule was a time of upheaval in Russia.[91] In a 2005 Kremlin speech, Putin characterized the collapse of the Soviet Union as the "greatest geopolitical catastrophe of the Twentieth Century."[92] Putin elaborated "Moreover, the epidemic of disintegration infected Russia itself."[93] The country's cradle-to-grave social safety net was gone and life expectancy declined in the period preceding Putin's rule.[94] In 2005, the National Priority Projects were launched to improve Russia's health care, education, housing and agriculture.[95][96]
+
+The continued criminal prosecution of Russia's then richest man, President of Yukos oil and gas company Mikhail Khodorkovsky, for fraud and tax evasion was seen by the international press as a retaliation for Khodorkovsky's donations to both liberal and communist opponents of the Kremlin.[citation needed] The government said that Khodorkovsky was "corrupting" a large segment of the Duma to prevent changes to the tax code.[citation needed] Khodorkovsky was arrested, Yukos was bankrupted and the company's assets were auctioned at below-market value, with the largest share acquired by the state company Rosneft.[97] The fate of Yukos was seen as a sign of a broader shift of Russia towards a system of state capitalism.[98][99] This was underscored in July 2014 when shareholders of Yukos were awarded $50 billion in compensation by the Permanent Arbitration Court in The Hague.[100]
+
+On 7 October 2006, Anna Politkovskaya, a journalist who exposed corruption in the Russian army and its conduct in Chechnya, was shot in the lobby of her apartment building, on Putin's birthday. The death of Politkovskaya triggered international criticism, with accusations that Putin had failed to protect the country's new independent media.[101][102] Putin himself said that her death caused the government more problems than her writings.[103]
+
+In 2007, "Dissenters' Marches" were organized by the opposition group The Other Russia,[104] led by former chess champion Garry Kasparov and national-Bolshevist leader Eduard Limonov. Following prior warnings, demonstrations in several Russian cities were met by police action, which included interfering with the travel of the protesters and the arrests of as many as 150 people who attempted to break through police lines.[105]
+
+On 12 September 2007, Putin dissolved the government upon the request of Prime Minister Mikhail Fradkov. Fradkov commented that it was to give the President a "free hand" in the run-up to the parliamentary election. Viktor Zubkov was appointed the new prime minister.[106]
+
+In December 2007, United Russia won 64.24% of the popular vote in their run for State Duma according to election preliminary results.[107] United Russia's victory in the December 2007 elections was seen by many as an indication of strong popular support of the then Russian leadership and its policies.[108][109]
+
+Putin was barred from a third consecutive term by the Constitution. First Deputy Prime Minister Dmitry Medvedev was elected his successor. In a power-switching operation on 8 May 2008, only a day after handing the presidency to Medvedev, Putin was appointed Prime Minister of Russia, maintaining his political dominance.[110]
+
+Putin has said that overcoming the consequences of the world economic crisis was one of the two main achievements of his second Premiership.[96] The other was the stabilizing the size of Russia's population between 2008 and 2011 following a long period of demographic collapse that began in the 1990s.[96]
+
+At the United Russia Congress in Moscow on 24 September 2011, Medvedev officially proposed that Putin stand for the Presidency in 2012, an offer Putin accepted. Given United Russia's near-total dominance of Russian politics, many observers believed that Putin was assured of a third term. The move was expected to see Medvedev stand on the United Russia ticket in the parliamentary elections in December, with a goal of becoming Prime Minister at the end of his presidential term.[111]
+
+After the parliamentary elections on 4 December 2011, tens of thousands of Russians engaged in protests against alleged electoral fraud, the largest protests in Putin's time. Protesters criticized Putin and United Russia and demanded annulment of the election results.[112] Those protests sparked the fear of a colour revolution in society.[113][114][115] Putin allegedly organized a number of paramilitary groups loyal to himself and to the United Russia party in the period between 2005 and 2012.[116]
+
+On 24 September 2011, while speaking at the United Russia party congress, Medvedev announced that he would recommend the party nominate Putin as its presidential candidate. He also revealed that the two men had long ago cut a deal to allow Putin to run for president in 2012.[117] This switch was termed by many in the media as "Rokirovka", the Russian term for the chess move "castling". Medvedev said he himself would be ready to perform "practical work in the government".[118]
+
+On 4 March 2012, Putin won the 2012 Russian presidential elections in the first round, with 63.6% of the vote, despite widespread accusations of vote-rigging.[78][119][120] Opposition groups accused Putin and the United Russia party of fraud.[121][122] While efforts to make the elections transparent were publicized, including the usage of webcams in polling stations, the vote was criticized by the Russian opposition and by international observers from the Organization for Security and Co-operation in Europe for procedural irregularities.[123]
+
+Anti-Putin protests took place during and directly after the presidential campaign. The most notorious protest was the Pussy riot performance on 21 February, and subsequent trial.[124] An estimated 8,000–20,000 protesters gathered in Moscow on 6 May,[125][126] when eighty people were injured in confrontations with police,[127] and 450 were arrested, with another 120 arrests taking place the following day.[128] A counter-protest of Putin supporters occurred which culminated in a gathering of an estimated 130,000 supporters at the Luzhniki Stadium, Russia's largest stadium. Some of the attendees stated that they had been paid to come, were forced to come by their employers, or were misled into believing that they were going to attend a folk festival instead.[129][130][131][132] The rally is considered to be the largest in support of Putin to date.[133]
+
+Putin's presidency was inaugurated in the Kremlin on 7 May 2012.[134] On his first day as president, Putin issued 14 Presidential decrees, which are sometimes called the "May Decrees" by the media, including a lengthy one stating wide-ranging goals for the Russian economy. Other decrees concerned education, housing, skilled labor training, relations with the European Union, the defense industry, inter-ethnic relations, and other policy areas dealt with in Putin's program articles issued during the presidential campaign.[135]
+
+In 2012 and 2013, Putin and the United Russia party backed stricter legislation against the LGBT community, in Saint Petersburg, Archangelsk and Novosibirsk; a law called the Russian gay propaganda law, that is against "homosexual propaganda" (which prohibits such symbols as the rainbow flag as well as published works containing homosexual content) was adopted by the State Duma in June 2013.[136][137][138][139] Responding to international concerns about Russia's legislation, Putin asked critics to note that the law was a "ban on the propaganda of pedophilia and homosexuality" and he stated that homosexual visitors to the 2014 Winter Olympics should "leave the children in peace" but denied there was any "professional, career or social discrimination" against homosexuals in Russia.[140]
+
+In June 2013, Putin attended a televised rally of the All-Russia People's Front where he was elected head of the movement,[141] which was set up in 2011.[142] According to journalist Steve Rosenberg, the movement is intended to "reconnect the Kremlin to the Russian people" and one day, if necessary, replace the increasingly unpopular United Russia party that currently backs Putin.[143]
+
+In 2014, Russia made several military incursions into Ukrainian territory. After the Euromaidan protests and the fall of Ukrainian president Viktor Yanukovych, Russian soldiers without insignias took control of strategic positions and infrastructure within the Ukrainian territory of Crimea. Russia then annexed the Republic of Crimea and City of Sevastopol after a referendum in which Crimeans voted to join the Russian Federation, according to official results.[144][145][146] Subsequently, demonstrations against Ukrainian Rada legislative actions by pro-Russian groups in the Donbass area of Ukraine escalated into an armed conflict between the Ukrainian government and the Russia-backed separatist forces of the self-declared Donetsk and Lugansk People's Republics. In August Russian military vehicles crossed the border in several locations of Donetsk Oblast.[147][148][149][150] The incursion by the Russian military was seen[by whom?] as responsible for the defeat of Ukrainian forces in early September.[151][152]
+
+In November 2014, the Ukrainian military reported intensive movement of troops and equipment from Russia into the separatist-controlled parts of eastern Ukraine.[153] The Associated Press reported 80 unmarked military vehicles on the move in rebel-controlled areas.[154] An OSCE Special Monitoring Mission observed convoys of heavy weapons and tanks in DPR-controlled territory without insignia.[155] OSCE monitors further stated that they observed vehicles transporting ammunition and soldiers' dead bodies crossing the Russian-Ukrainian border under the guise of humanitarian-aid convoys.[156] As of early August 2015, the OSCE observed over 21 such vehicles marked with the Russian military code for soldiers killed in action.[157] According to The Moscow Times, Russia has tried to intimidate and silence human-rights workers discussing Russian soldiers' deaths in the conflict.[158] The OSCE repeatedly reported that its observers were denied access to the areas controlled by "combined Russian-separatist forces".[159]
+
+The majority of members of the international community and organizations such as Amnesty International have condemned Russia for its actions in post-revolutionary Ukraine, accusing it of breaking international law and of violating Ukrainian sovereignty. Many countries implemented economic sanctions against Russia, Russian individuals or companies –  to which Russia responded in kind.
+
+In October 2015, The Washington Post reported that Russia had redeployed some of its elite units from Ukraine to Syria in recent weeks to support Syrian President Bashar al-Assad.[160] In December 2015, Russian Federation President Putin admitted that Russian military intelligence officers were operating in Ukraine.[161]
+
+Many[quantify] members of the international community assumed that Putin's annexation of Crimea had initiated a completely new kind of Russian foreign policy.[162]
+They[who?] took the annexation of Crimea to mean that his foreign policy had shifted "from state-driven foreign policy" to taking an offensive stance to re-create the Soviet Union.[162] However, this policy shift can be understood[by whom?] as Putin trying to defend nations in Russia's sphere of influence from encroaching western power. While the act to annex the Crimea was bold and drastic, his "new" foreign policy may have more similarities to his older policies.[162]
+
+On 30 September 2015, President Putin authorized Russian military intervention in the Syrian Civil War, following a formal request by the Syrian government for military help against rebel and jihadist groups.[163]
+
+The Russian military activities consisted of air strikes, cruise missile strikes and the use of front line advisors and Russian special forces against militant groups opposed to the Syrian government, including the Syrian opposition, as well as Islamic State of Iraq and the Levant (ISIL), al-Nusra Front (al-Qaeda in the Levant), Tahrir al-Sham, Ahrar al-Sham and the Army of Conquest.[164][165] After Putin's announcement on 14 March 2016 that the mission he had set for the Russian military in Syria had been "largely accomplished" and ordered the withdrawal of the "main part" of the Russian forces from Syria,[166] Russian forces deployed in Syria continued to actively operate in support of the Syrian government.[167]
+
+In January 2017, a U.S. intelligence community assessment expressed "high confidence" that Putin personally ordered an "influence campaign," initially to denigrate Hillary Clinton and to harm her electoral chances and potential presidency, then later developing "a clear preference" for Donald Trump.[169][170] Both Trump[171][172] and Putin has consistently denied any Russian interference in the U.S. election.[173][174][175][176][177][178] The New York Times reported in July 2018 that the CIA had long nurtured a Russian source who eventually rose to a position close to Putin, allowing the source to pass key information in 2016 about Putin's direct involvement.[179] Suspected CIA's mole named as Oleg Smolenkov is now reported to be living in the United States.[180]
+
+Putin won the 2018 presidential election with more than 76% of the vote.[181] His fourth term began on 7 May 2018,[182] which will last until 2024.[183] On the same day, Putin invited Dmitry Medvedev to form a new government.[184] On 15 May 2018, Putin took part in the opening of the movement along the highway section of the Crimean bridge.[185] On 18 May 2018, Putin signed decrees on the composition of the new Government.[186] On 25 May 2018, Putin announced that he would not run for president in 2024, justifying this in compliance with the Russian Constitution.[187] On 14 June 2018, Putin opened the 21st FIFA World Cup, which took place in Russia for the first time.
+
+In September 2019, Putin's administration interfered with the results of Russia's nationwide regional elections, and manipulated it by eliminating all candidates in the opposition. The event that was aimed at contributing to the ruling party,  United Russia's victory, also contributed to inciting mass protests for democracy, leading to large-scale arrests and cases of police brutality.[188]
+
+On 15 January 2020, Dmitry Medvedev and his entire government resigned after Vladimir Putin's Address to the Federal Assembly. Putin suggested major constitutional amendments prior to his retirement in 2024.[189] At the same time, on behalf of Putin, he continued to exercise his powers until the formation of a new government.[190] The president suggested that Medvedev take the newly created post of Deputy Chairman of the Security Council.[191]
+
+On the same day, Putin nominated Mikhail Mishustin, head of the country's Federal Tax Service for the post of Prime Minister. The next day, he was confirmed by the State Duma to the post[192][193] and appointed Prime Minister by Putin's decree.[194] This was the first time ever that a PM was confirmed without any votes against. On 21 January 2020, Mishustin presented to Vladimir Putin a draft structure of his Cabinet. On the same day, the President signed a decree on the structure of the Cabinet and appointed the proposed Ministers.[195][196][197]
+
+On 15 March 2020, Putin instructed to form a Working Group of the State Council to counteract the spread of coronavirus. Putin appointed Moscow Mayor Sergey Sobyanin as the head of the Group.[198]
+
+On 22 March 2020, after a phone call with Italian Prime Minister Giuseppe Conte, Putin arranged the Russian army to send military medics, special disinfection vehicles and other medical equipment to Italy, which was the European country hardest hit by the COVID-19 pandemic.[199]
+
+On 24 March 2020, Putin visited a hospital in Moscow's Kommunarka, where patients with coronavirus are kept, where he spoke with them and with doctors.[200] A week later, the chief doctor of the hospital, Denis Protsenko, with whom Putin met, tested positive for coronavirus. Since then, Vladimir Putin began working remotely from his office at Novo-Ogaryovo. He began holding meetings with the government and other officials via video conference. According to Dmitry Peskov, Putin passes daily tests for coronavirus, and his health is not in danger.[201][202]
+
+On 25 March, President Putin announced in a televised address to the nation that the 22 April constitutional referendum would be postponed due to the coronavirus.[203] He added that the next week would be a nationwide paid holiday and urged Russians to stay at home.[204][205] Putin also announced a list of measures of social protection, support for small and medium-sized enterprises, and changes in fiscal policy.[206] Putin announced following measures for microenterprises, small- and medium-sized businesses: deferring tax payments (except Russia's value-added tax) for the next six months, cutting the size of social security contributions in half, deferring social security contributions, deferring loan repayments for the next six months, a six-month moratorium on fines, debt collection, and creditors' applications for bankruptcy of debtor enterprises. Additionally, a new tax on income from large deposits will be introduced in 2021, and the tax on offshores will be increased.[207][208][209][210] On 2 April, Putin again issued an address in which he announced prolongation of the non-working time until 30 April.[211] Putin likened Russia's fight against COVID-19 to Russia's battles with invading Pecheneg and Cuman steppe nomads in the 10th and 11th centuries.[212] On 19 April, Putin declared that "The situation is under full control".[213] On 28 April, Putin declared that "We cannot relax. The situation is still very difficult."[214] In a 24 to 27 April Levada poll, 48% of Russian respondents said that they disapproved of Putin's handling of the coronavirus pandemic[215] and his strict isolation and lack of leadership during the crisis was widely commented as sign of losing his "strongman" image.[216][217]
+
+Putin signed an executive order on 3 July 2020 to officially insert amendments into the Russian Constitution. These amendments took effect on 4 July 2020.[218]
+
+Putin's domestic policies, particularly early in his first presidency, were aimed at creating a vertical power structure. On 13 May 2000, he issued a decree putting the 89 federal subjects of Russia into seven administrative federal districts and appointed a presidential envoy responsible for each of those districts (whose official title is Plenipotentiary Representative).[219]
+
+According to Stephen White, under the presidency of Putin Russia made it clear that it had no intention of establishing a "second edition" of the American or British political system, but rather a system that was closer to Russia's own traditions and circumstances.[220] Some commentators have described Putin's administration as a "sovereign democracy".[221][222][223] According to the proponents of that description (primarily Vladislav Surkov), the government's actions and policies ought above all to enjoy popular support within Russia itself and not be directed or influenced from outside the country.[224] The practice of the system is however characterized by Swedish economist Anders Åslund:[225]
+
+After Putin resumed the presidency in 2012, his rule is best described as "manual management" as the Russians like to put it. Putin does whatever he wants, with little consideration to the consequences with one important caveat. During the Russian financial crash of August 1998, Putin learned that financial crises are politically destabilizing and must be avoided at all costs. Therefore, he cares about financial stability.
+
+The period after 2012 also saw mass protests against the falsification of elections, censorship and toughening of free assembly laws.
+
+In July 2000, according to a law proposed by Putin and approved by the Federal Assembly of Russia, Putin gained the right to dismiss the heads of the 89 federal subjects. In 2004, the direct election of those heads (usually called "governors") by popular vote was replaced with a system whereby they would be nominated by the president and approved or disapproved by regional legislatures.[226][227] This was seen by Putin as a necessary move to stop separatist tendencies and get rid of those governors who were connected with organised crime.[228] This and other government actions effected under Putin's presidency have been criticised by many independent Russian media outlets and Western commentators as anti-democratic.[229][230] In 2012, as proposed by Putin's successor, Dmitry Medvedev, the direct election of governors was re-introduced.[231]
+
+During his first term in office, Putin opposed some of the Yeltsin-era oligarchs, as well as his political opponents, resulting in the exile or imprisonment of such people as Boris Berezovsky, Vladimir Gusinsky, and Mikhail Khodorkovsky; other oligarchs such as Roman Abramovich and Arkady Rotenberg are friends and allies with Putin.[232]
+
+Putin succeeded in codifying land law and tax law and promulgated new codes on labor, administrative, criminal, commercial and civil procedural law.[233] Under Medvedev's presidency, Putin's government implemented some key reforms in the area of state security, the Russian police reform and the Russian military reform.[234]
+
+Fueled by the 2000s commodities boom including record high oil prices,[10][11] under the Putin administration from 2001 to 2007, the economy made real gains of an average 7% per year,[235] making it the 7th largest economy in the world in purchasing power. In 2007, Russia's GDP exceeded that of Russian SFSR in 1990, having recovered from the 1998 financial crisis and the preceding recession in the 1990s.[236] By 2008, Russia's GDP measured by purchasing power increased by 72%.[237][238]
+
+During Putin's first eight years in office, industry grew substantially, as did production, construction, real incomes, credit, and the middle class.[236][239][240] Putin has also been praised for eliminating widespread barter and thus boosting the economy.[241] Inflation remained a problem however.[236]
+
+A fund for oil revenue allowed Russia to repay all of the Soviet Union's debts by 2005.[236] Russia joined the World Trade Organization on 22 August 2012.[242]
+
+Control over the economy was increased by placing individuals from the intelligence services and the military in key positions of the Russian economy, including on boards of large companies.
+In 2005, an industry consolidation programme was launched to bring the main aircraft producing companies under a single umbrella organization, the United Aircraft Corporation (UAC). The aim was to optimize production lines and minimise losses.[243] The UAC is one of Russia's "national champions" and comparable to EADS in Europe.[244]
+
+A program was introduced with the aim of increasing Russia's share of the European energy market by building submerged gas pipelines bypassing Ukraine and other countries which were often seen as non-reliable transit partners by Russia, especially following the Russia-Ukraine gas disputes of the late 2000s. Russia also undermined the rival Nabucco pipeline project by buying gas from Turkmenistan and redirecting it into Russian pipelines.[citation needed]
+
+Russia diversified its export markets by building the Trans-Siberian oil pipeline to support oil exports to China, Japan and Korea, as well as the Sakhalin–Khabarovsk–Vladivostok gas pipeline in the Russian Far East. Russia has also recently built several major oil and gas refineries, plants and ports. Major hydropower plants such as the Bureya Dam and the Boguchany Dam have been constructed, as well as the restoration of the nuclear industry of Russia, with 1 trillion rubles ($42.7 billion) which were allocated from the federal budget to nuclear power and industry development before 2015.[245] Many nuclear power stations and units are currently being constructed by the state corporation Rosatom in Russia and abroad.[citation needed]
+
+A construction program of floating nuclear power plants is intended to provide power to Russian Arctic coastal cities and gas rigs, starting in 2012.[246][247] The Arctic policy of Russia also includes an offshore oilfield in the Pechora Sea which is expected to start producing in early 2012, with the world's first ice-resistant oil platform and first offshore Arctic platform.[248] In August 2011, Rosneft, a Russian government-operated oil company, signed a deal with ExxonMobil for Arctic oil production.[249]
+
+The construction of a pipeline at a cost of $77  billion, to be jointly funded by Russia and China, was signed off on by Putin in Shanghai on 21 May 2014. On completion, in an estimated 4 to 6 years, the pipeline would deliver natural gas from the state-majority-owned Gazprom to China's state-owned China National Petroleum Corporation for the next 30 years, in a deal worth $400bn.[250]
+
+In 2014, the Organized Crime and Corruption Reporting Project named Putin their Person of the Year Award for furthering corruption and organized crime.[251][252]
+
+As noted by Russian journalists after the 2018 presidential inauguration, Putin has since 2007 repeatedly predicted that Russia will become "one of the world's fifth largest economies" roughly within 10 years from that date; thus far this target has not been achieved.[253]
+
+The ongoing financial crisis began in the second half of 2014 when the Russian ruble collapsed due to a decline in the price of oil and international sanctions against Russia. These events in turn led to loss of investor confidence and capital flight.[254] Though it has also been argued that the sanctions had little to no effect on Russia's economy.[255][256]
+
+Energy, trade, and finance agreements with China worth $25 billion were signed in October 2014 in an effort to compensate for international sanctions. The following year, a $400 billion 30-year natural gas supply agreement was also signed with China.[257]
+
+In 2004, President Putin signed the Kyoto Protocol treaty designed to reduce greenhouse gases.[258] However, Russia did not face mandatory cuts, because the Kyoto Protocol limits emissions to a percentage increase or decrease from 1990 levels and Russia's greenhouse-gas emissions fell well below the 1990 baseline due to a drop in economic output after the breakup of the Soviet Union.[259]
+
+Putin personally supervises a number of protection programmes for rare and endangered animals in Russia, such as the Amur tiger, the white whale, the polar bear and the snow leopard.[260][261][262][263]
+
+Buddhism, Eastern Orthodox Christianity, Islam and Judaism, defined by law as Russia's traditional religions and a part of Russia's historical heritage,[264] enjoyed limited state support in the Putin era. The vast construction and restoration of churches, started in the 1990s, continued under Putin, and the state allowed the teaching of religion in schools (parents are provided with a choice for their children to learn the basics of one of the traditional religions or secular ethics). His approach to religious policy has been characterized as one of support for religious freedoms, but also the attempt to unify different religions under the authority of the state.[265] In 2012, Putin was honored in Bethlehem and a street was named after him.[266]
+
+Putin regularly attends the most important services of the Russian Orthodox Church on the main Orthodox Christian holidays. He established a good relationship with Patriarchs of the Russian Church, the late Alexy II of Moscow and the current Kirill of Moscow. As president, he took an active personal part in promoting the Act of Canonical Communion with the Moscow Patriarchate, signed 17 May 2007 that restored relations between the Moscow-based Russian Orthodox Church and the Russian Orthodox Church Outside Russia after the 80-year schism.[267]
+
+Under Putin, the Hasidic FJCR became increasingly influential within the Jewish community, partly due to the influence of Federation-supporting businessmen mediated through their alliances with Putin, notably Lev Leviev and Roman Abramovich.[268][269] According to the JTA, Putin is popular amongst the Russian Jewish community, who see him as a force for stability. Russia's chief rabbi, Berel Lazar, said Putin "paid great attention to the needs of our community and related to us with a deep respect".[270] In 2016, Ronald S. Lauder, the president of the World Jewish Congress, also praised Putin for making Russia "a country where Jews are welcome".[271]
+
+The resumption of long-distance flights of Russia's strategic bombers was followed by the announcement by Russian Defense Minister Anatoliy Serdyukov during his meeting with Putin on 5 December 2007, that 11 ships, including the aircraft carrier Kuznetsov, would take part in the first major navy sortie into the Mediterranean since Soviet times.[272] The sortie was to be backed up by 47 aircraft, including strategic bombers.[273]
+
+While from the early 2000s Russia started placing more money into its military and defense industry, it was only in 2008 that the full-scale Russian military reform began, aiming to modernize the Russian Armed Forces and making them significantly more effective. The reform was largely carried out by Defense Minister Anatoly Serdyukov during Medvedev's presidency, under the supervision of both Putin, as the Head of Government, and Medvedev, as the Commander-in-Chief of the Russian Armed Forces.
+
+Key elements of the reform included reducing the armed forces to a strength of one million; reducing the number of officers; centralising officer training from 65 military schools into 10 'systemic' military training centres; creating a professional NCO corps; reducing the size of the central command; introducing more civilian logistics and auxiliary staff; elimination of cadre-strength formations; reorganising the reserves; reorganising the army into a brigade system, and reorganising air forces into an air base system instead of regiments.[274]
+
+The number of Russia's military districts was reduced to four. The term of draft service was reduced from two years to one, which put an end to the old harassment traditions in Russian army, since all conscripts became very close by draft age. The gradual transition to the majority professional army by the late 2010s was announced, and a large programme of supplying the Armed Forces with new military equipment and ships was started. The Russian Space Forces were replaced on 1 December 2011 with the Russian Aerospace Defence Forces.
+
+In spite of Putin's call for major investments in strategic nuclear weapons, these will fall well below the New START limits due to the retirement of aging systems.[275] After U.S. President George W. Bush withdrew from the 1972 Anti-Ballistic Missile Treaty, Putin responded by ordering a build-up of Russia's nuclear capabilities, designed to counterbalance U.S. capabilities.[276] Most analysts agree that Russia's nuclear strategy under Putin eventually brought it into violation of the 1987 Intermediate-Range Nuclear Forces Treaty. Because of this, U.S. President Donald Trump announced the U.S. would no longer consider itself bound by the treaty's provisions, raising nuclear tensions between the two powers.[277] This prompted Putin to state that Russia would not launch first in a nuclear conflict but would "annihilate" any adversary. Russians killed in such a conflict "will go to heaven as martyrs".[278] Most military analysts believe Russia would consider launching first if losing a major conventional conflict as part of an 'escalate to de-escalate' strategy that would bring adversaries to the negotiating table.[279]
+
+Putin has also sought to increase Russian territorial claims in the Arctic and its military presence here. In August 2007, Russian expedition Arktika 2007, part of research related to the 2001 Russian territorial extension claim, planted a flag on the seabed below the North Pole.[280] Both Russian submarines and troops deployed in the Arctic have been increasing.[281][282]
+
+An NGO based in the New York City; Human Rights Watch; in a report entitled Laws of Attrition, authored by Hugh Williamson, the British director of HRW's Europe & Central Asia Division, has claimed that since May 2012, when Putin was re-elected as president, Russia has enacted many restrictive laws, started inspections of nongovernmental organizations, harassed, intimidated, and imprisoned political activists, and started to restrict critics. The new laws include the "foreign agents" law, which is widely regarded as over-broad by including Russian human rights organizations which receive some international grant funding, the treason law, and the assembly law which penalizes many expressions of dissent.[283][284] Human rights activists have criticized Russia for censoring speech of LGBT activists due to "the gay propaganda law"[285] and increasing violence against LGBT+ people due to the law.[286][287][288] Putin has rejected accusations of human rights abuses.[289]
+
+Scott Gehlbach, an American Professor of Political Science at the University of Wisconsin–Madison, has claimed that since 1999, Putin has reportedly punished journalists who challenge his official point of view.[290] Maria Lipman, an American writing in Foreign Affairs (the journal of the Council on Foreign Relations), claims, "The crackdown that followed Putin's return to the Kremlin in 2012 extended to the liberal media, which had until then been allowed to operate fairly independently."[291] The Internet has attracted Putin's attention because his critics have tried to use it to challenge his control of information.[292] Marian K. Leighton, who worked for the CIA as a Soviet analyst in the 1980s says, "Having muzzled Russia's print and broadcast media, Putin focused his energies on the Internet."[293] Robert W. Orttung and Christopher Walker report:
+
+In the early 2000s, Putin and others in his government began promoting the idea in Russian media that they are the modern-day version of the 17th-century Romanov tsars who ended Russia's "Time of Troubles", meaning they claim to be the peacemakers and stabilizers after the fall of the Soviet Union.[295]
+
+Putin has promoted explicitly conservative policies in social, cultural and political matters, both at home and abroad. Putin has attacked globalism and neo-liberalism and is identified by scholars with Russian conservatism.[296] Putin has promoted new think tanks that bring together like-minded intellectuals and writers. For example, the Izborsky Club, founded in 2012 by the conservative right-wing journalist Alexander Prokhanov, stresses (i) Russian nationalism, (ii) the restoration of Russia's historical greatness, and (iii) systematic opposition to liberal ideas and policies.[297] Vladislav Surkov, a senior government official, has been one of the key economics consultants during Putin's presidency.[298]
+
+In cultural and social affairs Putin has collaborated closely with the Russian Orthodox Church. Patriarch Kirill of Moscow, head of the Church, endorsed his election in 2012 stating Putin's terms were like "a miracle of God."[299] Steven Myers reports, "The church, once heavily repressed, had emerged from the Soviet collapse as one of the most respected institutions... Now Kiril led the faithful directly into an alliance with the state."[300]
+
+Mark Woods, a Baptist minister and contributing editor to Christian Today, provides specific examples of how the Church has backed the expansion of Russian power into Crimea and eastern Ukraine.[301] More broadly, The New York Times reports in September 2016 how the Church's policy prescriptions support the Kremlin's appeal to social conservatives:
+
+In 2007, Putin led a successful effort on behalf of Sochi (located along the Black Sea near the border between Georgia and Russia) for the 2014 Winter Olympics and the 2014 Winter Paralympics,[303] the first Winter Olympic Games to ever be hosted by Russia. Likewise, in 2008, the city of Kazan won the bid for the 2013 Summer Universiade, and on 2 December 2010 Russia won the right to host the 2017 FIFA Confederations Cup and 2018 FIFA World Cup, also for the first time in Russian history. In 2013, Putin stated that gay athletes would not face any discrimination at the 2014 Sochi Winter Olympics.[304]
+
+Putin is chairman of the Russian Geographical Society's board of trustees and is actively engaged in the protection of rare species. The programs are being conducted by the Severtsov Institute of Ecology and Evolution at the Russian Academy of Sciences.[305]
+
+Putin spoke favorably of Artificial Intelligence in regards to foreign policy, “Artificial intelligence is the future, not only for Russia, but for all humankind.  It comes with colossal opportunities, but also threats that are difficult to predict.  Whoever becomes the leader in this sphere will become the ruler of the world.”[306]
+
+In 2012, Putin wrote an article in the Hindu newspaper, saying that "The Declaration on Strategic Partnership between India and Russia signed in October 2000 became a truly historic step".[307][308] Prime Minister Manmohan Singh during Putin's 2012 visit to India: "President Putin is a valued friend of India and the original architect of the India-Russia strategic partnership".[309]
+
+Putin's Russia maintains positive relations with other BRIC countries. The country has sought to strengthen ties especially with the People's Republic of China by signing the Treaty of Friendship as well as building the Trans-Siberian oil pipeline and Trans-Siberian gas pipeline geared toward growing Chinese energy needs.[310] The mutual-security cooperation of the two countries and their central Asian neighbours is facilitated by the Shanghai Cooperation Organisation (SCO) which was founded in 2001 in Shanghai by the leaders of China, Kazakhstan, Kyrgyzstan, Russia, Tajikistan, and Uzbekistan.[311]
+
+The announcement made during the SCO summit that Russia resumes on a permanent basis the long-distance patrol flights of its strategic bombers (suspended in 1992)[312][313] in the light of joint Russian-Chinese military exercises, first-ever in history held on Russian territory,[314] made some experts believe that Putin is inclined to set up an anti-NATO bloc or the Asian version of OPEC.[315] When presented with the suggestion that "Western observers are already likening the SCO to a military organization that would stand in opposition to NATO", Putin answered that "this kind of comparison is inappropriate in both form and substance".[312]
+
+A series of so-called colour revolutions in the post-Soviet states, namely the Rose Revolution in Georgia in 2003, the Orange Revolution in Ukraine in 2004 and the Tulip Revolution in Kyrgyzstan in 2005, led to frictions in the relations of those countries with Russia. In December 2004, Putin criticized the Rose and Orange revolutions, saying: "If you have permanent revolutions you risk plunging the post-Soviet space into endless conflict".[316]
+
+A number of economic disputes erupted between Russia and some neighbors, such as the Russian import ban of Georgian wine. And in some cases, such as the Russia–Ukraine gas disputes, the economic conflicts affected other European countries, for example when a January 2009 gas dispute with Ukraine led state-controlled Russian company Gazprom to halt its deliveries of natural gas to Ukraine,[317] which left a number of European states, to which Ukraine transits Russian gas, with serious shortages of natural gas in January 2009.[317]
+
+The plans of Georgia and Ukraine to become members of NATO have caused some tensions between Russia and those states.[318] In 2010, Ukraine did abandon these plans.[319] Putin allegedly declared at a NATO-Russia summit in 2008 that if Ukraine joined NATO Russia could contend to annex the Ukrainian East and Crimea.[320] At the summit, he told US President George W. Bush that "Ukraine is not even a state!" while the following year Putin referred to Ukraine as "Little Russia".[321] Following the 2014 Ukrainian revolution in March 2014, the Russian Federation annexed Crimea.[322][323][324] According to Putin, this was done because "Crimea has always been and remains an inseparable part of Russia".[325] After the Russian annexion of Crimea, he said that Ukraine includes "regions of Russia's historic south" and "was created on a whim by the Bolsheviks".[326] He went on to declare that the February 2014 ousting of Ukrainian President Viktor Yanukovych had been orchestrated by the West as an attempt to weaken Russia. "Our Western partners have crossed a line. They behaved rudely, irresponsibly and unprofessionally," he said, adding that the people who had come to power in Ukraine were "nationalists, neo-Nazis, Russophobes and anti-Semites".[326] In a July 2014 speech midst an armed insurgency in Eastern Ukraine, Putin stated he would use Russia's "entire arsenal" and "the right of self defence" to protect Russian speakers outside Russia.[327] With the split of the Ukrainian orthodox church from the Russian one in 2018, a number of experts came to the conclusion that Putin's policy of forceful engagement in post-Soviet republics significantly backfired on him, leading to a situation where he "annexed Crimea, but lost Ukraine", and provoked a much more cautious approach to Russia among other post-Soviet countries.[328][329]
+
+In late August 2014, Putin stated: "People who have their own views on history and the history of our country may argue with me, but it seems to me that the Russian and Ukrainian peoples are practically one people".[330] After making a similar statement, in late December 2015 he stated: "the Ukrainian culture, as well as Ukrainian literature, surely has a source of its own".[331]
+
+In August 2008, Georgian President Mikheil Saakashvili attempted to restore control over the breakaway South Ossetia. However, the Georgian military was soon defeated in the resulting 2008 South Ossetia War after regular Russian forces entered South Ossetia and then Georgia proper, then also opened a second front in the other Georgian breakaway province of Abkhazia with Abkhazian forces.[332][333]
+
+Despite existing or past tensions between Russia and most of the post-Soviet states, Putin has followed the policy of Eurasian integration. Putin endorsed the idea of a Eurasian Union in 2011;[334][335] the concept was proposed by the President of Kazakhstan in 1994.[336] On 18 November 2011, the presidents of Belarus, Kazakhstan and Russia signed an agreement setting a target of establishing the Eurasian Union by 2015.[337] The Eurasian Union was established on 1 January 2015.[338]
+
+Under Putin, Russia's relationships with NATO and the U.S. have passed through several stages. When he first became president, relations were cautious, but after the 9/11 attacks Putin quickly supported the U.S. in the War on Terror and the opportunity for partnership appeared.[339] However, the U.S. responded by further expansion of NATO to Russia's borders and by unilateral withdrawal from the 1972 Anti-Ballistic Missile Treaty.[339]
+
+From 2003, when Russia did not support the Iraq War and when Putin became ever more distant from the West in his internal and external policies, relations continued to deteriorate. According to Russia scholar Stephen F. Cohen, the narrative of the mainstream U.S. media, following that of the White House, became anti-Putin.[339] In an interview with Michael Stürmer, Putin said there were three questions which most concerned Russia and Eastern Europe: namely, the status of Kosovo, the Treaty on Conventional Armed Forces in Europe and American plans to build missile defence sites in Poland and the Czech Republic, and suggested that all three were linked.[340] His view was that concessions by the West on one of the questions might be met with concessions from Russia on another.[340]
+
+In a January 2007 interview, Putin said Russia was in favor of a democratic multipolar world and strengthening the systems of international law.[341]
+
+In February 2007, Putin criticized what he called the United States' monopolistic dominance in global relations, and "almost uncontained hyper use of force in international relations". He said the result of it is that "no one feels safe! Because no one can feel that international law is like a stone wall that will protect them. Of course such a policy stimulates an arms race".[342] This came to be known as the Munich Speech, and former NATO secretary Jaap de Hoop Scheffer called the speech "disappointing and not helpful."[343] The months following Putin's Munich Speech[342] were marked by tension and a surge in rhetoric on both sides of the Atlantic. Both Russian and American officials, however, denied the idea of a new Cold War.[344]
+Putin publicly opposed plans for the U.S. missile shield in Europe and presented President George W. Bush with a counterproposal on 7 June 2007 which was declined.[345] Russia suspended its participation in the Conventional Forces in Europe treaty on 11 December 2007.[346]
+
+Putin opposed Kosovo's 2008 declaration of independence, warning supporters of that precedent that it would de facto destabilize the whole system of international relations.[347][348][349]
+
+Putin had good relations with former American President George W. Bush, and many European leaders. His "cooler" and "more business-like" relationship with Germany's current chancellor, Angela Merkel is often attributed to Merkel's upbringing in the former DDR, where Putin was stationed as a KGB agent.[350] He had a very friendly and warm relationship with the former Prime Minister of Italy Silvio Berlusconi;[351] the two leaders often described their relationship as a close friendship, continuing to organize bilateral meetings even after Berlusconi's resignation in November 2011.[352]
+
+In late 2013, Russian-American relations deteriorated further when the United States canceled a summit (for the first time since 1960) after Putin gave asylum to Edward Snowden, who had leaked classified information from the NSA.[353]
+
+Relations were further strained after the 2014–15 Russian military intervention in Ukraine and the Annexation of Crimea.[354]
+
+In 2014, Russia was suspended from the G8 group as a result of its annexation of Crimea.[355][356] However, in June 2015, Putin told an Italian newspaper that Russia has no intention of attacking NATO.[357]
+
+On 9 November 2016, Putin congratulated Donald Trump on becoming the 45th President of the United States.[358]
+
+In December 2016, US intelligence officials (headed by James Clapper) quoted by CBS News stated that Putin approved the email hacking and cyber attacks during the U.S. election, against the democratic presidential nominee Hillary Clinton. A spokesman for Putin denied the reports.[359] Putin has repeatedly accused Hillary Clinton, who served as U.S. Secretary of State from 2009 to 2013, of interfering in Russia's internal affairs,[360] and in December 2016, Clinton accused Putin of having a personal grudge against her.[361][362]
+
+With the election of Trump, Putin's favorability in the U.S. increased. A Gallup poll in February 2017 revealed a positive view of Putin among 22% of Americans, the highest since 2003.[363] However, Putin has stated that U.S.–Russian relations, already at the lowest level since the end of the Cold War,[364] have continued to deteriorate after Trump took office in January 2017.[365]
+
+On 18 June 2020, The National Interest published a nine thousand words essay by Putin, titled 'The Real Lessons of the 75th Anniversary of World War II'.[366] In the essay, Putin criticizes the western historical view of the Molotov–Ribbentrop Pact as the start of World War II, stating that the Munich Agreement was the beginning.[367]
+
+In 2003, relations between Russia and the United Kingdom deteriorated when the United Kingdom granted political asylum to Putin's former patron, oligarch Boris Berezovsky.[368] This deterioration was intensified by allegations that the British were spying and making secret payments to pro-democracy and human rights groups.[369]
+
+The end of 2006 brought more strained relations in the wake of the death by polonium poisoning of former KGB and FSB officer Alexander Litvinenko in London, who became an MI6 agent in 2003. In 2007, the crisis in relations continued with expulsion of four Russian envoys over Russia's refusal to extradite former KGB bodyguard Andrei Lugovoi to face charges in the murder of Litvinenko.[368] Mirroring the British actions, Russia expelled UK diplomats and took other retaliatory steps.[368]
+
+In 2015–16, the British Government conducted an inquiry into the death of Alexander Litvinenko. Its report was released in January 2016.[370] According to the report, "The FSB operation to kill Mr Litvinenko was probably approved by Mr Patrushev and also by President Putin." The report outlined some possible motives for the murder, including Litvinenko's public statements and books about the alleged involvement of the FSB in mass murder, and what was "undoubtedly a personal dimension to the antagonism" between Putin and Litvinenko, led to the murder. Media analyst William Dunkerley, writing in The Guardian, criticised the inquiry as politically motivated, biased, lacking in evidence, and logically inconsistent.[371] The Kremlin dismissed the Inquiry as "a joke" and "whitewash".[372][373]
+
+Poisoning of Sergei Skripal
+
+On 4 March 2018, former double agent Sergei Skripal was poisoned with a Novichok nerve agent in Salisbury.[374] 10 days later, the British government formally accused the Russian state of attempted murder, a charge which Russia denied.[375] After the UK expelled 23 Russian diplomats (an action which would later be responded to with a Russian expulsion of 23 British diplomats),[376] British Foreign Secretary Boris Johnson said on 16 March that it was "overwhelmingly likely" Putin had personally ordered the poisoning of Skripal. Putin's spokesman Dmitry Peskov called the allegation "shocking and unpardonable diplomatic misconduct".[377]
+
+Putin and his successor, Medvedev, enjoyed warm relations with the late Hugo Chávez of Venezuela. Much of this has been through the sale of military equipment; since 2005, Venezuela has purchased more than $4 billion worth of arms from Russia.[378] In September 2008, Russia sent Tupolev Tu-160 bombers to Venezuela to carry out training flights.[379] In November 2008, both countries held a joint naval exercise in the Caribbean. Earlier in 2000, Putin had re-established stronger ties with Fidel Castro's Cuba.[380]
+
+In September 2007, Putin visited Indonesia and in doing so became the first Russian leader to visit the country in more than 50 years.[381] In the same month, Putin also attended the APEC meeting held in Sydney where he met with John Howard, who was the Australian Prime Minister at the time, and signed a uranium trade deal for Australia to sell uranium to Russia. This was the first visit by a Russian president to Australia.[382]
+
+On 16 October 2007, Putin visited Iran to participate in the Second Caspian Summit in Tehran,[383][384] where he met with Iranian President Mahmoud Ahmadinejad.[385][386] This was the first visit of a Soviet or Russian leader[387] to Iran since Joseph Stalin's participation in the Tehran Conference in 1943, and thus marked a significant event in Iran-Russia relations.[388] At a press conference after the summit Putin said that "all our (Caspian) states have the right to develop their peaceful nuclear programmes without any restrictions".[389]
+
+Subsequently, under Medvedev's presidency, Iran-Russia relations were uneven: Russia did not fulfill the contract of selling to Iran the S-300, one of the most potent anti-aircraft missile systems currently existing. However, Russian specialists completed the construction of Iran and the Middle East's first civilian nuclear power facility, the Bushehr Nuclear Power Plant, and Russia has continuously opposed the imposition of economic sanctions on Iran by the U.S. and the EU, as well as warning against a military attack on Iran. Putin was quoted as describing Iran as a "partner",[340] though he expressed concerns over the Iranian nuclear programme.[340]
+
+In April 2008, Putin became the first Russian President who visited Libya.[390] Putin condemned the foreign military intervention of Libya, he called UN resolution as "defective and flawed," and added "It allows everything. It resembles medieval calls for crusades."[391][392] Upon the death of Muammar Gaddafi, Putin called it as "planned murder" by the US, saying: "They showed to the whole world how he (Gaddafi) was killed," and "There was blood all over. Is that what they call a democracy?"[393][394]
+
+Regarding Syria, from 2000 to 2010 Russia sold around $1.5 billion worth of arms to that country, making Damascus Moscow's seventh-largest client.[395]
+During the Syrian civil war, Russia threatened to veto any sanctions against the Syrian government,[396] and continued to supply arms to the regime.
+
+Putin opposed any foreign intervention. In June 2012, in Paris, he rejected the statement of French President François Hollande who called on Bashar Al-Assad to step down. Putin echoed Assad's argument that anti-regime militants were responsible for much of the bloodshed. He also talked about previous NATO interventions and their results, and asked "What is happening in Libya, in Iraq? Did they become safer? Where are they heading? Nobody has an answer".[397]
+
+On 11 September 2013, The New York Times published an op-ed by Putin urging caution against US intervention in Syria and criticizing American exceptionalism.[398] Putin subsequently helped to arrange for the destruction of Syria's chemical weapons.[399] In 2015, he took a stronger pro-Assad stance[400] and mobilized military support for the regime. Some analysts have summarized Putin as being allied with Shiites and Alawites in the Middle East.[401][402]
+
+In October 2019, Russian President Vladimir Putin visited the United Arab Emirates, where six agreements were struck with Abu Dhabi Crown Prince Mohammed bin Zayed. One of them included shared investments between Russian sovereign wealth fund and the Emirati investment fund Mubadala. The two nations signed deals worth over $1.3bn, in energy, health and advance technology sectors.[403]
+
+Stephen Kotkin, a professor at Princeton University, says that Russia's high-tech industry is dependent on Israel. "Russia's hemorrhage of human capital has not helped. How many émigrés from Russia form a part of Israel's high tech sector is hard to say [...] many Russian-born engineers in Israel could only find employment as service workers, housemaids, and welders. Either way, they do not work in Russia."[306]
+
+President Putin has attended the BRICS (Brazil, Russia, India, China and South Africa) Summit conferences since 2013.
+
+According to a June 2007 public opinion survey, Putin's approval rating was 81%, the second highest of any leader in the world that year.[404] In January 2013, at the time of 2011–2013 Russian protests, Putin's approval rating fell to 62%, the lowest figure since 2000 and a ten-point drop over two years.[405] By May 2014, following the 2014 Ukrainian revolution and annexation of Crimea, Putin's approval rating had rebounded to 85.9%, a six-year high.[406]
+
+After EU and U.S. sanctions against Russian officials as a result of the 2014 pro-Russian unrest in Ukraine, Putin's approval rating reached 87 percent, according to a Levada Center survey published on 6 August 2014.[407][408] In February 2015, based on new domestic polling, Putin was ranked the world's most popular politician.[409] In June 2015, Putin's approval rating climbed to 89%, an all-time high.[410][411][412] In 2016, the approval rating was 81%.[413]
+
+Observers saw Putin's high approval ratings in 2010's as a consequence of significant improvements in living standards, and Russia's reassertion of itself on the world scene during his presidency.[414][415]
+
+Despite high approval for Putin, confidence in the Russian economy was low, dropping to levels in 2016 that rivaled the recent lows in 2009 at the height of the global economic crisis. Just 14% of Russians in 2016 said their national economy was getting better, and 18% said this about their local economies.[416] Putin's performance at reining in corruption is also unpopular among Russians. Newsweek reported in June 2017 that "An opinion poll by the Moscow-based Levada Center indicated that 67 percent held Putin personally responsible for high-level corruption".[417]
+
+In July 2018, Putin's approval rating fell to 63% and just 49% would vote for Putin if presidential elections were held.[419] Levada poll results published in September 2018 showed Putin's personal trustworthiness levels at 39% (decline from 59% in November 2017)[420] with the main contributing factor being the presidential support of the unpopular pension reform and economic stagnation.[421][422] In October 2018, two-thirds of Russians surveyed in Levada poll agreed that "Putin bears full responsibility for the problems of the country" which has been attributed[423] to decline of a popular belief in "good tsar and bad boyars", a traditional attitude towards justifying failures of top of ruling hierarchy in Russia.[424]
+
+In January 2019, the percentage of Russians trusting the president hit a then-historic minimum – 33.4%.[425] It declined further to 31.7% in May 2019[426] which led to a dispute between the VCIOM and President's administration office, who accused it of incorrectly using an open question, after which VCIOM repeated the poll with a closed question getting 72.3%.[427] Nonetheless, in April 2019 Gallup poll showed a record number of Russians (20%) willing to permanently emigrate from Russia.[428] The decline is even larger in the 17–25 age group, "who find themselves largely disconnected from the country's aging leadership, nostalgic Soviet rhetoric and nepotistic agenda", according to a report prepared by Vladimir Milov. The percentage of people willing to emigrate permanently in this age group is 41% and 60% has favorable views on the United States (three times more than in the 55+ age group).[429] Decline in support for president and the government is also visible in other polls, such as rapidly growing readiness to protest against poor living conditions.[427]
+
+In November 2019, in a Levada poll, 53% respondents aged 18–24 declared they would like to permanently emigrate from Russia.[430] In May 2020, amid the COVID-19 crisis, Putin's approval rating was 67.9%, measured by VCIOM when respondents were presented a list of names,[431] and 27% when respondents were expected to name politicians they trust.[432] In a closed-question survey conducted by Levada, the approval rating was 59%[433] which has been attributed to continued post-Crimea economic stagnation but also an apathetic response to the pandemic crisis in Russia.[434]
+
+Critics state that Putin has moved Russia in an autocratic direction.[436] Putin has been described as a "dictator" by political opponent Garry Kasparov, as a "bully" and "arrogant" by former U.S. Secretary of State Hillary Clinton, and as "self-centered" and an "isolationist" by the Dalai Lama.[437][438][439][440][441] Former U.S. Secretary of State Henry Kissinger wrote in 2014 that the West has demonized Putin.[442] Egon Krenz, former leader of East Germany, said the Cold War never ended and that, "After weak presidents like Gorbachev and Yeltsin, it is a great fortune for Russia that it has [President Vladimir] Putin."[443]
+
+Many Russians credit Putin for reviving Russia's fortunes.[444] Former Soviet Union leader Mikhail Gorbachev, while acknowledging the flawed democratic procedures and restrictions on media freedom during the Putin presidency, said that Putin had pulled Russia out of chaos at the end of the Yeltsin years, and that Russians "must remember that Putin saved Russia from the beginning of a collapse."[444][445] In 2015, opposition politician Boris Nemtsov said that Putin was turning Russia into a "raw materials colony" of China.[446] Chechen Republic head and Putin supporter, Ramzan Kadyrov, states that Putin saved both the Chechen people and Russia.[447]
+
+Russia has suffered democratic backsliding during Putin's tenure. Freedom House has listed Russia as being "not free" since 2005.[448] Experts do not generally consider Russia to be a democracy, citing purges and jailing of political opponents, curtailed press freedom, and the lack of free and fair elections.[17][18][19][20][21][449][450][451][452][453][454][455][456] In 2004, Freedom House warned that Russia's "retreat from freedom marks a low point not registered since 1989, when the country was part of the Soviet Union."[457] The Economist Intelligence Unit has rated Russia as "authoritarian" since 2011,[458] whereas it had previously been considered a "hybrid regime" (with "some form of democratic government" in place) as late as 2007.[459] According to political scientist, Larry Diamond, writing in 2015, "no serious scholar would consider Russia today a democracy".[460]
+
+Putin cultivates an outdoor, sporty, tough guy public image, demonstrating his physical prowess and taking part in unusual or dangerous acts, such as extreme sports and interaction with wild animals,[461] part of a public relations approach that, according to Wired, "deliberately cultivates the macho, take-charge superhero image".[462] For example, in 2007, the tabloid Komsomolskaya Pravda published a huge photograph of a shirtless Putin vacationing in the Siberian mountains under the headline: "Be Like Putin."[463] Some of the activities have been criticised for being staged.[464][465] Outside of Russia, his macho image has been the subject of parody.[466][467][468] Putin is believed to be self-conscious about his height, which has been estimated by Kremlin insiders at between 155 cm (5 ft 2 in) and 165 cm (5 ft 5 in) tall but is usually given at 170 cm (5 ft 7 in).[469][470]
+
+Notable examples of Putin's adventures include flying military jets, practising martial arts, riding horses, rafting, and fishing and swimming in a cold Siberian river, many of which he did shirtless.[471][463] Other examples are descending in a deep-water submersible, tranquilizing tigers and polar bears,[463][472][473] riding a motorbike,[474] co-piloting a firefighting plane to dump water on a raging fire,[462] shooting darts at whales from a crossbow for eco-tracking,[475] driving a race car,[471][476] scuba diving at an archaeological site,[464][477] attempting to lead endangered cranes in a motorized hang glider,[478] and catching large fish.[479][480]
+
+There are many songs about Putin.[481] Some of the more well-known ones include "Go Hard Like Vladimir Putin" by K. King and Beni Maniaci,[482] "VVP" by Tajik singer Tolibjon Kurbankhanov,[483][484] "Our Madhouse is Voting for Putin" by Working Faculty, and "A Song About Putin" by the Russian Airborne Troops band.[485] There is also the song "Putin khuylo!" which originally emerged as anti-Putin chants by Ukrainian football fans and spread in Ukraine (among supporters of Euromaidan), then to other countries.[486] A song called "A Man Like Putin" by Poyushchie vmeste was also a hit across Russia, topping the Russian Music Charts in 2002.[487]
+
+Putin's name and image are widely used in advertisement and product branding.[462] Among the Putin-branded products are Putinka vodka, the PuTin brand of canned food, the Gorbusha Putina caviar, and a collection of T-shirts with his image.[488] In 2015, his advisor was found dead after days of excessive consumption of alcohol, though this was later ruled an accident.[489]
+
+In 2007, he was the Time Person of the Year.[490][491] In 2015, he was No. 1 on the Time's Most Influential People List.[492][493][494] Forbes ranked him the World's Most Powerful Individual every year from 2013 to 2016.[495] He was ranked the second most powerful individual by Forbes in 2018, only behind China's paramount leader Xi Jinping.[496]
+
+Putin has produced many aphorisms and catch-phrases known as putinisms.[497] Many of them were first made during his annual Q&A conferences, where Putin answered questions from journalists and other people in the studio, as well as from Russians throughout the country, who either phoned in or spoke from studios and outdoor sites across Russia. Putin is known for his often tough and sharp language, often alluding to Russian jokes and folk sayings.[497]
+
+Putin sometimes uses Russian criminal jargon (fenya), albeit not always correctly.[498]
+
+On 28 July 1983, Putin married Lyudmila Shkrebneva, and they lived together in East Germany from 1985 to 1990. They have two daughters, Mariya Putina, born 28 April 1985 in Leningrad, and Yekaterina Putina, born 31 August 1986 in Dresden, East Germany.[501]
+
+In April 2008, the Moskovsky Korrespondent reported that Putin had divorced Shkrebneva and was engaged to marry rhythmic gymnast Alina Kabaeva.[2] The story was denied[2] and the newspaper was shut down shortly thereafter.[3] Putin and Shkrebneva continued to make public appearances together as spouses, while the status of his relationship with Kabaeva became a topic of speculation.[502][503][504][505] In the subsequent years, there were frequent reports that Putin and Kabaeva had multiple children together, although these reports were denied.[506] In 2015, Kabaeva reportedly gave birth to a daughter; Putin is alleged to be the father.[506][503][4]
+
+On 6 June 2013, Putin and Shkrebneva announced that their marriage was over, and, on 1 April 2014, the Kremlin confirmed that the divorce had been finalized.[507][508][509]
+
+Putin has two grandsons, born in 2012 and 2017.[510][511]
+
+His cousin, Igor Putin, was a director at Moscow based Master Bank and was accused in a number of money laundering scandals.[512][513]
+
+Official figures released during the legislative election of 2007 put Putin's wealth at approximately 3.7 million rubles (US$150,000) in bank accounts, a private 77.4-square-meter (833 sq ft) apartment in Saint Petersburg, and miscellaneous other assets.[514][515] Putin's reported 2006 income totaled 2 million rubles (approximately $80,000). In 2012, Putin reported an income of 3.6 million rubles ($113,000).[516][517]
+
+Putin has been photographed wearing a number of expensive wristwatches, collectively valued at $700,000, nearly six times his annual salary.[518][519] Putin has been known on occasion to give watches valued at thousands of dollars as gifts to peasants and factory workers.[520]
+
+According to Russian opposition politicians and journalists, Putin secretly possesses a multi-billion dollar fortune[521][522] via successive ownership of stakes in a number of Russian companies.[523][524] According to one editorial in The Washington Post, "Putin might not technically own these 43 aircraft, but, as the sole political power in Russia, he can act like they're his".[525] Russian RIA journalist argued that "[Western] intelligence agencies (...) could not find anything". These contradictory claims were analyzed by Polygraph.info[526] which looked at a number of reports by Western (Anders Åslund estimate of $100–160 billion) and Russian (Stanislav Belkovsky estimated of $40 billion) analysts, CIA (estimate of $40 billion in 2007) as well as counterarguments of Russian media. Polygraph concluded:
+
+There is uncertainty on the precise sum of Putin's wealth, and the assessment by the Director of U.S. National Intelligence apparently is not yet complete. However, with the pile of evidence and documents in the Panama Papers and in the hands of independent investigators such as those cited by Dawisha, Polygraph.info finds that Danilov's claim that Western intelligence agencies have not been able to find evidence of Putin's wealth to be misleading
+
+In April 2016, 11 million documents belonging to Panamanian law firm Mossack Fonseca were leaked to the German newspaper Süddeutsche Zeitung and the Washington-based International Consortium of Investigative Journalists. The name of Vladimir Putin does not appear in any of the records, and Putin denied his involvement with the company.[527] However, various media have reported on three of Putin's associates on the list.[528] According to the Panama Papers leak, close trustees of Putin own offshore companies worth US$2 billion in total.[529] The German newspaper Süddeutsche Zeitung regards the possibility of Putin's family profiting from this money as plausible.[530][531]
+
+According to the paper, the US$2 billion had been "secretly shuffled through banks and shadow companies linked to Putin's associates", such as construction billionaires Arkady and Boris Rotenberg, and Bank Rossiya, previously identified by the U.S. State Department as being treated by Putin as his personal bank account, had been central in facilitating this. It concludes that "Putin has shown he is willing to take aggressive steps to maintain secrecy and protect [such] communal assets."[532][533] A significant proportion of the money trail leads to Putin's best friend Sergei Roldugin. Although a musician, and in his own words, not a businessman, it appears he has accumulated assets valued at $100m, and possibly more. It has been suggested he was picked for the role because of his low profile.[528] There have been speculations that Putin, in fact, owns the funds,[534] and Roldugin just acted as a proxy. Putin himself denied it,[527][535] and his press-secretary, Dmitry Peskov, said the leak was a conspiracy aimed at Putin.[536]
+
+As president and prime-minister, Putin has lived in numerous official residences throughout the country.[537] These residences include: the Moscow Kremlin, Novo-Ogaryovo in Moscow Oblast, the White House in Moscow, Gorki-9 [ru] near Moscow, Bocharov Ruchey in Sochi, Dolgiye Borody [ru] in Novgorod Oblast, and Riviera in Sochi.[538]
+
+In August 2012, critics of President Vladimir Putin listed the ownership of 20 villas and palaces, nine of which were built during Putin's 12 years in power.[539]
+
+Soon after Putin returned from his KGB service in Dresden, East Germany, he built a dacha in Solovyovka on the eastern shore of Lake Komsomolskoye on the Karelian Isthmus in Priozersky District of Leningrad Oblast, near St. Petersburg. After the dacha burned down in 1996, Putin built a new one identical to the original and was joined by a group of seven friends who built dachas nearby. In 1996, the group formally registered their fraternity as a co-operative society, calling it Ozero ("Lake") and turning it into a gated community.[540]
+
+A massive Italianate-style mansion costing an alleged US$1 billion[541] and dubbed "Putin's Palace" is under construction near the Black Sea village of Praskoveevka. The mansion, built on government land and sporting 3 helipads, and a private road paid for from state funds and guarded by officials wearing uniforms of the official Kremlin guard service, is said to have been built for Putin's private use.[by whom?] In 2012, Sergei Kolesnikov, a former business associate of Putin's, told the BBC's Newsnight programme that he had been ordered by Deputy Prime Minister Igor Sechin to oversee the building of the palace.[542] Putin's spokesman Dmitry Peskov dismissed Kolesnikov's allegations against Putin as untrue, saying that "Putin has never had any relationship to this palace."[543]
+
+Putin's female black Labrador Retriever Konni was often seen at the President's side, and was sometimes allowed to attend meetings when Putin greeted world leaders during their visits to Russia.
+
+Putin has four dogs, Buffy, Yume, Verni and Pasha. Buffy, a Karakachan dog, was given to President Putin in November 2010 by the Bulgarian Prime Minister, Boyko Borisov. Yume is an Akita Inu dog which arrived in Moscow in July 2012 as a three-month-old puppy as the Akita Prefecture's gift to show gratitude for Russia's assistance to Japan after the devastating earthquake and tsunami in 2011.[544]
+Verni, which is an Alabai – a Turkmen-bred variety of the Central Asia shepherd dog – was a birthday gift from the leader of Turkmenistan during a meeting in Sochi in October 2017.[545] Putin received Pasha, a Šarplaninac puppy as a gift from Serbia during his state visit in January 2019.[546]
+
+Putin is Russian Orthodox. His mother was a devoted Christian believer who attended the Russian Orthodox Church, while his father was an atheist.[547][548] Though his mother kept no icons at home, she attended church regularly, despite government persecution of her religion at that time. His mother secretly baptized him as a baby, and she regularly took him to services.[28]
+
+According to Putin, his religious awakening began after a serious car crash involving his wife in 1993, and a life-threatening fire that burned down their dacha in August 1996.[548] Shortly before an official visit to Israel, Putin's mother gave him his baptismal cross, telling him to get it blessed. Putin states, "I did as she said and then put the cross around my neck. I have never taken it off since."[28] When asked in 2007 whether he believes in God, he responded, "... There are things I believe, which should not in my position, at least, be shared with the public at large for everybody's consumption because that would look like self-advertising or a political striptease."[549] Putin's rumoured confessor is Russian Orthodox Bishop Tikhon Shevkunov.[550]
+However, the sincerity of his Christianity has been rejected by his former advisor Sergei Pugachev.[551]
+
+Putin is frequently seen promoting sports—including skiing, badminton, cycling, and fishing—and a healthy lifestyle among Russians.[555][556]
+
+Putin watches football and supports FC Zenit Saint Petersburg.[557] He displays an interest in ice hockey and bandy.[558]
+
+Putin began training in sambo at the age of fourteen, before switching to judo, which he continues to practice.[559] Putin won competitions in both sports in Leningrad (now Saint Petersburg). Putin was awarded eighth dan of the black belt in 2012, becoming the first Russian to achieve the status.[560] Putin also practises karate.[561]
+
+Putin co-authored a book entitled Judo with Vladimir Putin in Russian, and Judo: History, Theory, Practice in English (2004).[562] Benjamin Wittes, a black belt in taekwondo and aikido and editor of Lawfare, has disputed Putin's martial arts skills, stating that there is no video evidence of Putin displaying any actual noteworthy judo skills.[563][564]

en/6022.html.txt

@@ -0,0 +1,49 @@
+
+
+VLC media player (previously the VideoLAN Client and commonly known as simply VLC) is a free and open-source portable cross-platform media player software and streaming media server developed by the VideoLAN project. VLC is available for desktop operating systems and mobile platforms, such as Android, iOS,  iPadOS,  Tizen, Windows 10 Mobile and Windows Phone. VLC is also available on digital distribution platforms such as Apple's App Store, Google Play and Microsoft Store.
+
+VLC supports many audio and video compression methods and file formats, including DVD-Video, video CD and streaming protocols. It is able to stream media over computer networks and to transcode multimedia files.[17]
+
+The default distribution of VLC includes many free decoding and encoding libraries, avoiding the need for finding/calibrating proprietary plugins. The libavcodec library from the FFmpeg project provides many of VLC's codecs, but the player mainly[18] uses its own muxers and demuxers. It also has its own protocol implementations. It also gained distinction as the first player to support playback of encrypted DVDs on Linux and macOS by using the libdvdcss DVD decryption library, however this library is legally controversial and is not included in many software repositories of Linux distributions as a result.[19][20]
+
+The VideoLan software originated as an academic project in 1996. VLC used to stand for "VideoLAN Client" when VLC was a client of the VideoLAN project. Since VLC is no longer merely a client, that initialism no longer applies.[21][22] It was intended to consist of a client and server to stream videos from satellite dishes across a campus network. Originally developed by students at the École Centrale Paris, it is now developed by contributors worldwide and is coordinated by VideoLAN, a non-profit organization. Rewritten from scratch in 1998, it was released under GNU General Public License on February 1, 2001, with authorization from the headmaster of the École Centrale Paris. The functionality of the server program, VideoLan Server (VLS), has mostly been subsumed into VLC and has been deprecated.[23] The project name has been changed to VLC media player because there is no longer a client/server infrastructure. The cone icon used in VLC is a reference to the traffic cones collected by École Centrale's Networking Students' Association.[24] The cone icon design was changed from a hand drawn low resolution icon[25] to a higher resolution CGI-rendered version in 2006, illustrated by Richard Øiestad.[26]
+
+In 2007 the VLC project decided, for license compatibility reasons, not to upgrade to just released GPLv3.[27] After 13 years of development, version 1.0.0 of VLC media player was released on July 7, 2009.[28] Work began on VLC for Android in 2010 and it has been available for Android devices on the Google Play store since 2011.[29][30] In September 2010, a company named "Applidium" developed a VLC port for iOS under GPLv2 with the endorsement of the VLC project, which was accepted by Apple for their App Store.[31][32] In January 2011, after VLC developer Rémi Denis-Courmont's complaint to Apple about the licensing conflict between the VLC's GPLv2 and the App store's policies,[33] the VLC had been withdrawn from the Apple App Store by Apple.[34] Subsequently, in October 2011 the VLC authors began to relicense the engine parts of VLC from the GPLv2 to the LGPLv2 to achieve better license compatibility, for instance with the Apple App Store.[35][36][37][38] In July 2013 the VLC application could be resubmitted to the iOS App Store under the Mozilla Public License.[39] Version 2.0.0 of VLC media player was released on February 18, 2012.[15][40] The version for the Windows Store was released on March 13, 2014. Support for Windows RT, Windows Phone and Xbox One were added later.[41] As of 2016[update] VLC is the third in the sourceforge.net overall download count,[42] and there have been more than 3 billion downloads.[43]
+
+Version 3.0 was in development for Windows, Linux and macOS since June 2016[44] and released in February 2018.[45] It contains many new features including Chromecast output support (except subtitles[46]), hardware-accelerated decoding, 4K and 8K playback, 10-bit and HDR playback, 360° video and 3D audio, audio passthrough for HD audio codecs, Blu-ray Java menu support, and local network drive browsing.
+
+In December 2017 the European Parliament approved a budget that funds a bug bounty program for VLC to improve the EU's IT infrastructure.[47]
+
+VLC, like most multimedia frameworks, has a very modular design which makes it easier to include modules/plugins for new file formats, codecs, interfaces, or streaming methods. VLC 1.0.0 has more than 380 modules.[53] The VLC core creates its own graph of modules dynamically, depending on the situation: input protocol, input file format, input codec, video card capabilities and other parameters. In VLC, almost everything is a module, like interfaces, video and audio outputs, controls, scalers, codecs, and audio/video filters.
+
+The default GUI is based on Be API on BeOS, Cocoa for macOS, and Qt 4 for Linux and Windows, but all give a similar standard interface. The old default GUI was based on wxWidgets on Linux and Windows.[54] VLC supports highly customizable skins through the skins2 interface,[55] and also supports Winamp 2 and XMMS skins.[56] Skins are not supported in the macOS version.[57] VLC has ncurses,[58] remote control,[59] and telnet[60] console interfaces. There is also an HTTP[61] interface, as well as interfaces for mouse gestures and keyboard hotkeys.[62]
+
+Because VLC is a packet-based media player it plays almost all video content. It can play some, even if they're damaged, incomplete, or unfinished, such as files that are still downloading via a peer-to-peer (P2P) network. It also plays m2t MPEG transport streams (.TS) files while they are still being digitized from an HDV camera via a FireWire cable, making it possible to monitor the video as it is being played. The player can also use libcdio to access .iso files so that users can play files on a disk image, even if the user's operating system cannot work directly with .iso images.
+
+VLC supports all audio and video formats supported by libavcodec and libavformat. This means that VLC can play back H.264 or MPEG-4 Part 2 video as well as support FLV or MXF file formats "out of the box" using FFmpeg's libraries. Alternatively, VLC has modules for codecs that are not based on FFmpeg's libraries. VLC is one of the free software DVD players that ignore DVD region coding on RPC-1 firmware drives, making it a region-free player. However, it does not do the same on RPC-2 firmware drives, as in these cases the region coding is enforced by the drive itself, however, it can still brute-force the CSS encryption to play a foreign-region DVD on an RPC-2 drive. VLC media player has some filters that can distort, rotate, split, deinterlace, and mirror videos as well as create display walls or add a logo overlay. It can also output video as ASCII art.
+
+VLC media player can play high-definition recordings of D-VHS tapes duplicated to a computer using CapDVHS.exe. This offers another way to archive all D-VHS tapes with the DRM copy freely tag. Using a FireWire connection from cable boxes to computers, VLC can stream live, unencrypted content to a monitor or HDTV. VLC media player can display the playing video as the desktop wallpaper, like Windows DreamScene, by using DirectX, only available on Windows operating systems. VLC media player can record the desktop and save the stream as a file, allowing the user to create screencasts.[63][64][65] On Microsoft Windows, VLC also supports the Direct Media Object (DMO) framework and can thus make use of some third-party DLLs (Dynamic-link library). On most platforms, VLC can tune into and view DVB-C, DVB-T, and DVB-S channels. On macOS the separate EyeTV plugin is required, on Windows it requires the card's BDA Drivers.
+
+VLC can be installed or run directly from a USB flash drive or other external drive. VLC can be extended through scripting; it uses the Lua scripting language.[66][67] VLC can play videos in the AVCHD format, a highly compressed format used in recent HD camcorders. VLC can generate a number of music visualization displays. The program is able to convert media files into various supported formats.[68]
+
+VLC media player is cross-platform, with versions for Windows, Android, Chrome OS, BeOS, Windows Phone, iOS, iPadOS, macOS, tvOS, OS/2, Linux, Syllable.[12] However, forward and backward compatibility between versions of VLC media player and different versions of OSs are not maintained over more than a couple or so generations.[69] 64-bit builds are available for 64-bit Windows.[70]
+
+The VLC port for Windows 8 and Windows 10 is backed by a crowdfunding campaign on Kickstarter to add support for a new GUI based on Microsoft's Metro design language, that will run on the Windows Runtime. All the existing features including video filters, subtitle support, and an equalizer are present in Windows 8.[71] A beta version of VLC for Windows 8 was released to the Microsoft Store on March 13, 2014.[72] A universal app was created for Windows 8, 8.1, 10, Windows Phone 8, 8.1 and Windows 10 Mobile.
+
+In May 2012, the VLC team stated that a version of VLC for Android was being developed.[73] The stable release version 1.0 was made available on Google Play on December 8, 2014.[74]
+
+Several APIs can connect to VLC and use its functionality:
+
+On Windows, Linux, macOS, and some other Unix-like platforms, VLC provides an NPAPI plugin, which enables users to view QuickTime, Windows Media, MP3, and Ogg files embedded in websites without using additional software. It supports many web browsers including Firefox, Mozilla Application Suite, and other Netscape plug-in based browsers; Safari, Chrome, and other WebKit based browsers; and Opera. Google used this plugin to build the Google Video Player web browser plugin before switching to use Adobe Flash.[84]
+
+Starting with version 0.8.2, VLC also provides an ActiveX plugin, which lets people view QuickTime (MOV), Windows Media, MP3, and Ogg files embedded in websites when using Internet Explorer.
+
+VLC can handle some incomplete files and in some cases can be used to preview files being downloaded. Several programs make use of this, including eMule and KCeasy. The free/open-source Internet television application Miro also uses VLC code. HandBrake, an open-source video encoder, used to load libdvdcss from VLC Media Player.[85] A program named Livestreamer may utilize VLC as its main video stream player and will not work without one. Easy Subtitles Synchronizer, a freeware subtitle editing program for Windows, uses VLC to preview the video with the edited subtitles.
+
+VLC can read many formats, depending on the operating system it is running on, including:[86]
+
+VLC can transcode or stream audio and video into several formats depending on the operating system, including:
+
+The VLC media player software installers for the macOS platform and the Windows platform include the libdvdcss DVD decryption library, even though this library may be legally restricted in certain jurisdictions.[90][91]
+
+The VLC media player software is able to read audio and video data from DVDs that incorporate Content Scramble System (CSS) encryption, even though the VLC media player software lacks a CSS decryption license.[92] The unauthorized decryption of CSS-encrypted DVD content or unauthorized distribution of CSS decryption tools may violate the US Digital Millennium Copyright Act.[92] Decryption of CSS-encrypted DVD content has been temporarily authorized for certain purposes (such as documentary filmmaking that uses short portions of DVD content for criticism or commentary) under the Digital Millennium Copyright Act anticircumvention exemptions that were issued by the US Copyright Office in 2010.[93] However these exemptions do not change the DMCA's ban on the distribution of CSS decryption tools; including those distributed with VLC.[94]

en/6023.html.txt

@@ -0,0 +1,150 @@
+
+
+North America · South America · Europe · Australia
+
+The track on a railway or railroad, also known as the permanent way, is the structure consisting of the rails, fasteners, railroad ties (sleepers, British English) and ballast (or slab track), plus the underlying subgrade. It enables trains to move by providing a dependable surface for their wheels to roll upon. For clarity it is often referred to as railway track (British English and UIC terminology) or railroad track (predominantly in the United States). Tracks where electric trains or electric trams run are equipped with an electrification system such as an overhead electrical power line or an additional electrified rail.
+
+The term permanent way also refers to the track in addition to lineside structures such as fences.
+
+Notwithstanding modern technical developments, the overwhelmingly dominant track form worldwide consists of flat-bottom steel rails supported on timber or pre-stressed concrete sleepers, which are themselves laid on crushed stone ballast.
+
+Most railroads with heavy traffic utilize continuously welded rails supported by sleepers attached via base plates that spread the load. A plastic or rubber pad is usually placed between the rail and the tie plate where concrete sleepers are used. The rail is usually held down to the sleeper with resilient fastenings, although cut spikes are widely used in North American practice. For much of the 20th century, rail track used softwood timber sleepers and jointed rails, and a considerable extent of this track type remains on secondary and tertiary routes. The rails were typically of flat bottom section fastened to the sleepers with dog spikes through a flat tie plate in North America and Australia, and typically of bullhead section carried in cast iron chairs in British and Irish practice.  The London, Midland and Scottish Railway pioneered the conversion to flat-bottomed rail and the supposed advantage of bullhead rail - that the rail could be turned over and re-used when the top surface had become worn - turned out to be unworkable in practice because the underside was usually ruined by fretting from the chairs.
+
+Jointed rails were used at first because contemporary technology did not offer any alternative. However, the intrinsic weakness in resisting vertical loading results in the ballast becoming depressed and a heavy maintenance workload is imposed to prevent unacceptable geometrical defects at the joints. The joints also needed to be lubricated, and wear at the fishplate (joint bar) mating surfaces needed to be rectified by shimming. For this reason jointed track is not financially appropriate for heavily operated railroads.
+
+Timber sleepers are of many available timbers, and are often treated with creosote, Chromated copper arsenate, or other wood preservatives. Pre-stressed concrete sleepers are often used where timber is scarce and where tonnage or speeds are high. Steel is used in some applications.
+
+The track ballast is customarily crushed stone, and the purpose of this is to support the sleepers and allow some adjustment of their position, while allowing free drainage.
+
+traditional railway track (showing ballast, part of sleeper and fixing mechanisms)
+
+Track of Singapore LRT
+
+Ballastless high-speed track in China
+
+A disadvantage of traditional track structures is the heavy demand for maintenance, particularly surfacing (tamping) and lining to restore the desired track geometry and smoothness of vehicle running. Weakness of the subgrade and drainage deficiencies also lead to heavy maintenance costs. This can be overcome by using ballastless track. In its simplest form this consists of a continuous slab of concrete (like a highway structure) with the rails supported directly on its upper surface (using a resilient pad).
+
+There are a number of proprietary systems, and variations include a continuous reinforced concrete slab, or alternatively the use of pre-cast pre-stressed concrete units laid on a base layer. Many permutations of design have been put forward.
+
+However, ballastless track has a high initial cost, and in the case of existing railroads the upgrade to such requires closure of the route for a long period. Its whole-life cost can be lower because of the reduction in maintenance. Ballastless track is usually considered for new very high speed or very high loading routes, in short extensions that require additional strength (e.g. railway stations), or for localised replacement where there are exceptional maintenance difficulties, for example in tunnels. Most rapid transit lines and rubber-tyred metro systems use ballastless track.[1]
+
+Early railways (c. 1840s) experimented with continuous bearing railtrack, in which the rail was supported along its length, with examples including Brunel's baulk road on the Great Western Railway, as well as use on the Newcastle and North Shields Railway,[2] on the Lancashire and Yorkshire Railway to a design by John Hawkshaw, and elsewhere.[3] Continuous-bearing designs were also promoted by other engineers.[4] The system was tested on the Baltimore and Ohio railway in the 1840s, but was found to be more expensive to maintain than rail with cross sleepers.[5]
+
+This type of track still exists on some bridges on Network Rail where the timber baulks are called waybeams or longitudinal timbers. Generally the speed over such structures is low.[6]
+
+Later applications of continuously supported track include Balfour Beatty's 'embedded slab track', which uses a rounded rectangular rail profile (BB14072) embedded in a slipformed (or pre-cast) concrete base (development 2000s).[7][8] The 'embedded rail structure', used in the Netherlands since 1976, initially used a conventional UIC 54 rail embedded in concrete, and later developed (late 1990s) to use a 'mushroom' shaped SA42 rail profile; a version for light rail using a rail supported in an asphalt concrete–filled steel trough has also been developed (2002).[9]
+
+Modern ladder track can be considered a development of baulk road. Ladder track utilizes sleepers aligned along the same direction as the rails with rung-like gauge restraining cross members. Both ballasted and ballastless types exist.
+
+Modern track typically uses hot-rolled steel with a profile of an asymmetrical rounded I-beam.[10] Unlike some other uses of iron and steel, railway rails are subject to very high stresses and have to be made of very high-quality steel alloy. It took many decades to improve the quality of the materials, including the change from iron to steel. The stronger the rails and the rest of the trackwork, the heavier and faster the trains the track can carry.
+
+Other profiles of rail include: bullhead rail; grooved rail; "flat-bottomed rail" (Vignoles rail or flanged T-rail); bridge rail (inverted U–shaped used in baulk road); and Barlow rail (inverted V).
+
+North American railroads until the mid- to late-20th century used rails 39 feet (12 m) long so they could be carried in gondola cars (open wagons), often 40 feet (12 m) long; as gondola sizes increased, so did rail lengths.
+
+According to the Railway Gazette the planned-but-cancelled 150-kilometre rail line for the Baffinland Iron Mine, on Baffin Island, would have used older carbon steel alloys for its rails, instead of more modern, higher performance alloys, because modern alloy rails can become brittle at very low temperatures.[11]
+
+The earliest rails were made of wood, which wore out quickly. Hardwood such as jarrah and karri were better than softwoods such as fir.  Longitudinal sleepers such as Brunel's baulk road are topped with iron or steel rails that are lighter than they might otherwise be because of the support of the sleepers.
+
+Early North American railroads used iron on top of wooden rails as an economy measure but gave up this method of construction after the iron came loose, began to curl and went into the floors of the coaches. The iron strap rail coming through the floors of the coaches came to be referred to as "snake heads" by early railroaders.[12][13]
+
+Rail is graded by weight over a standard length.  Heavier rail can support greater axle loads and higher train speeds without sustaining damage than lighter rail, but at a greater cost. In North America and the United Kingdom, rail is graded by its linear density in pounds per yard (usually shown as pound or lb), so 130-pound rail would weigh 130 lb/yd (64 kg/m). The usual range is 115 to 141 lb/yd (57 to 70 kg/m). In Europe, rail is graded in kilograms per metre and the usual range is 40 to 60 kg/m (81 to 121 lb/yd). The heaviest rail mass-produced was 155 pounds per yard (77 kg/m) and was rolled for the Pennsylvania Railroad. The United Kingdom is in the process of transition from the imperial to metric rating of rail.[14]
+
+The rails used in rail transport are produced in sections of fixed length. Rail lengths are made as long as possible, as the joints between rails are a source of weakness. Throughout the history of rail production, lengths have increased as manufacturing processes have improved.
+
+The following are lengths of single sections produced by steel mills, without any thermite welding.  Shorter rails may be welded with flashbutt welding, but the following rail lengths are unwelded.
+
+Welding of rails into longer lengths was first introduced around 1893, making train rides quieter and safer. With the introduction of thermite welding after 1899, the process became less labor-intensive and ubiquitous.[20]
+
+Modern production techniques allowed the production of longer unwelded segments.
+
+Newer longer rails tend to be made as simple multiples of older shorter rails, so that old rails can be replaced without cutting.  Some cutting would be needed as slightly longer rails are needed on the outside of sharp curves compared to the rails on the inside.
+
+Rails can be supplied pre-drilled with boltholes for fishplates or without where they will be welded into place. There are usually two or three boltholes at each end.
+
+Rails are produced in fixed lengths and need to be joined end-to-end to make a continuous surface on which trains may run. The traditional method of joining the rails is to bolt them together using metal fishplates (jointbars in the US), producing jointed track. For more modern usage, particularly where higher speeds are required, the lengths of rail may be welded together to form continuous welded rail (CWR).
+
+Jointed track is made using lengths of rail, usually around 20 m (66 ft) long (in the UK) and 39 or 78 ft (12 or 24 m) long (in North America), bolted together using perforated steel plates known as fishplates (UK) or joint bars (North America).
+
+Fishplates are usually 600 mm (2 ft) long, used in pairs either side of the rail ends and bolted together (usually four, but sometimes six bolts per joint). The bolts have alternating orientations so that in the event of a derailment and a wheel flange striking the joint, only some of the bolts will be sheared, reducing the likelihood of the rails misaligning with each other and exacerbating the derailment. This technique is not applied universally; European practice being to have all the bolt heads on the same side of the rail.
+
+Small gaps which function as expansion joints are deliberately left between the rail ends to allow for expansion of the rails in hot weather. European practice was to have the rail joints on both rails adjacent to each other, while North American practice is to stagger them. Because of these small gaps, when trains pass over jointed tracks they make a "clickety-clack" sound. Unless it is well-maintained, jointed track does not have the ride quality of welded rail and is less desirable for high speed trains. However, jointed track is still used in many countries on lower speed lines and sidings, and is used extensively in poorer countries due to the lower construction cost and the simpler equipment required for its installation and maintenance.
+
+A major problem of jointed track is cracking around the bolt holes, which can lead to breaking of the rail head (the running surface). This was the cause of the Hither Green rail crash which caused British Railways to begin converting much of its track to continuous welded rail.
+
+Where track circuits exist for signalling purposes, insulated block joints are required. These compound the weaknesses of ordinary joints. Specially-made glued joints, where all the gaps are filled with epoxy resin, increase the strength again.
+
+As an alternative to the insulated joint, audio frequency track circuits can be employed using a tuned loop formed in approximately 20 m (66 ft) of the rail as part of the blocking circuit.  Some insulated joints are unavoidable within turnouts.
+
+Another alternative is the axle counter, which can reduce the number of track circuits and thus the number of insulated rail joints required.
+
+Most modern railways use continuous welded rail (CWR), sometimes referred to as ribbon rails. In this form of track, the rails are welded together by utilising flash butt welding to form one continuous rail that may be several kilometres long. Because there are few joints, this form of track is very strong, gives a smooth ride, and needs less maintenance; trains can travel on it at higher speeds and with less friction. Welded rails are more expensive to lay than jointed tracks, but have much lower maintenance costs. The first welded track was used in Germany in 1924.[25] and has become common on main lines since the 1950s.
+
+The preferred process of flash butt welding involves an automated track-laying machine running a strong electric current through the touching ends of two unjoined rails. The ends become white hot due to electrical resistance and are then pressed together forming a strong weld. Thermite welding is used to repair or splice together existing CWR segments.  This is a manual process requiring a reaction crucible and form to contain the molten iron. Thermite-bonded joints are seen as less reliable and more prone to fracture or break.[26]
+
+North American practice is to weld 1⁄4 mile (400 m) long segments of rail at a rail facility and load it on a special train to carry it to the job site. This train is designed to carry many segments of rail which are placed so they can slide off their racks to the rear of the train and be attached to the ties (sleepers) in a continuous operation.[27]
+
+If not restrained, rails would lengthen in hot weather and shrink in cold weather. To provide this restraint, the rail is prevented from moving in relation to the sleeper by use of clips or anchors. Attention needs to be paid to compacting the ballast effectively, including under, between, and at the ends of the sleepers, to prevent the sleepers from moving. Anchors are more common for wooden sleepers, whereas most concrete or steel sleepers are fastened to the rail by special clips that resist longitudinal movement of the rail. There is no theoretical limit to how long a welded rail can be. However, if longitudinal and lateral restraint are insufficient, the track could become distorted in hot weather and cause a derailment. Distortion due to heat expansion is known in North America as sun kink, and elsewhere as buckling. In extreme hot weather special inspections are required to monitor sections of track known to be problematic. In North American practice extreme temperature conditions will trigger slow orders to allow for crews to react to buckling or "sun kinks" if encountered.[28]
+
+After new segments of rail are laid, or defective rails replaced (welded-in), the rails can be artificially stressed if the temperature of the rail during laying is cooler than what is desired. The stressing process involves either heating the rails, causing them to expand,[29] or stretching the rails with hydraulic equipment. They are then fastened (clipped) to the sleepers in their expanded form. This process ensures that the rail will not expand much further in subsequent hot weather. In cold weather the rails try to contract, but because they are firmly fastened, cannot do so. In effect, stressed rails are a bit like a piece of stretched elastic firmly fastened down.  In extremely cold weather, rails are heated to prevent "pull aparts".[30]
+
+CWR is laid (including fastening) at a temperature roughly midway between the extremes experienced at that location. (This is known as the "rail neutral temperature".) This installation procedure is intended to prevent tracks from buckling in summer heat or pulling apart in the winter cold. In North America, because broken rails (known as a pull-apart) are typically detected by interruption of the current in the signaling system, they are seen as less of a potential hazard than undetected heat kinks.
+
+Joints are used in the continuous welded rail when necessary, usually for signal circuit gaps. Instead of a joint that passes straight across the rail, the two rail ends are sometimes cut at an angle to give a smoother transition. In extreme cases, such as at the end of long bridges, a breather switch (referred to in North America and Britain as an expansion joint) gives a smooth path for the wheels while allowing the end of one rail to expand relative to the next rail.
+
+A sleeper (tie) is a rectangular object on which the rails are supported and fixed. The sleeper has two main roles: to transfer the loads from the rails to the track ballast and the ground underneath, and to hold the rails to the correct width apart (to maintain the rail gauge). They are generally laid transversely to the rails.
+
+Various methods exist for fixing the rail to the sleeper. Historically spikes gave way to cast iron chairs fixed to the sleeper, more recently springs (such as Pandrol clips) are used to fix the rail to the sleeper chair.
+
+Sometimes rail tracks are designed to be portable and moved from one place to another as required. During construction of the Panama Canal, tracks were moved around excavation works. These track gauge were 5 ft (1,524 mm) and the rolling stock full size.  Portable tracks have often been used in open pit mines. In 1880 in New York City, sections of heavy portable track (along with much other improvised technology) helped in the epic move of the ancient obelisk in Central Park to its final location from the dock where it was unloaded from the cargo ship SS Dessoug.
+
+Cane railways often had permanent tracks for the main lines, with portable tracks serving the canefields themselves.  These tracks were narrow gauge (for example, 2 ft (610 mm)) and the portable track came in straights, curves, and turnouts, rather like on a model railway.[31]
+
+Decauville was a source of many portable light rail tracks, also used for military purposes.
+
+The permanent way is so called because temporary way tracks were often used in the construction of that permanent way.
+
+The geometry of the tracks is three-dimensional by nature, but the standards that express the speed limits and other regulations in the areas of track gauge, alignment, elevation, curvature and track surface are usually expressed in two separate layouts for horizontal and vertical.
+
+Horizontal layout is the track layout on the horizontal plane. This involves the layout of three main track types: tangent track (straight line), curved track, and track transition curve (also called transition spiral or spiral) which connects between a tangent and a curved track.
+
+Vertical layout is the track layout on the vertical plane including the concepts such as crosslevel, cant and gradient.[32][33]
+
+A sidetrack is a railroad track other than siding that is auxiliary to the main track. The word is also used as a verb (without object) to refer to the movement of trains and railcars from the main track to a siding, and in common parlance to refer to giving in to distractions apart from a main subject.[34] Sidetracks are used by railroads to order and organize the flow of rail traffic.
+
+During the early days of rail, there was considerable variation in the gauge used by different systems. Today, 54.8% of the world's railways use a gauge of 1,435 mm (4 ft 8 1⁄2 in), known as standard or international gauge.[35][36] Gauges wider than standard gauge are called broad gauge; narrower, narrow gauge. Some stretches of track are dual gauge, with three (or sometimes four) parallel rails in place of the usual two, to allow trains of two different gauges to use the same track.[37]
+
+Gauge can safely vary over a range.  For example, U.S. federal safety standards allow standard gauge to vary from 4 ft 8 in (1,420 mm) to 4 ft 9 1⁄2 in (1,460 mm) for operation up to 60 mph (97 km/h).
+
+Track needs regular maintenance to remain in good order, especially when high-speed trains are involved. Inadequate maintenance may lead to a "slow order" (North American terminology, or Temporary speed restriction in the United Kingdom) being imposed to avoid accidents (see Slow zone). Track maintenance was at one time hard manual labour, requiring teams of labourers, or trackmen (US: gandy dancers; UK: platelayers; Australia: fettlers), who used lining bars to correct irregularities in horizontal alignment (line) of the track, and tamping and jacks to correct vertical irregularities (surface). Currently, maintenance is facilitated by a variety of specialised machines.
+
+The surface of the head of each of the two rails can be maintained by using a railgrinder.
+
+Common maintenance jobs include changing sleepers, lubricating and adjusting switches, tightening loose track components, and surfacing and lining track to keep straight sections straight and curves within maintenance limits. The process of sleeper and rail replacement can be automated by using a track renewal train.
+
+Spraying ballast with herbicide to prevent weeds growing through and redistributing the ballast is typically done with a special weed killing train.
+
+Over time, ballast is crushed or moved by the weight of trains passing over it, periodically requiring relevelling ("tamping") and eventually to be cleaned or replaced. If this is not done, the tracks may become uneven causing swaying, rough riding and possibly derailments. An alternative to tamping is to lift the rails and sleepers and reinsert the ballast beneath. For this, specialist "stoneblower" trains are used.
+
+Rail inspections utilize nondestructive testing methods to detect internal flaws in the rails. This is done by using specially equipped HiRail trucks, inspection cars, or in some cases handheld inspection devices.
+
+Rails must be replaced before the railhead profile wears to a degree that may trigger a derailment. Worn mainline rails usually have sufficient life remaining to be used on a branch line, siding or stub afterwards and are "cascaded" to those applications.
+
+The environmental conditions along railroad track create a unique railway ecosystem. This is particularly so in the United Kingdom where steam locomotives are only used on special services and vegetation has not been trimmed back so thoroughly. This creates a fire risk in prolonged dry weather.
+
+In the UK, the cess is used by track repair crews to walk to a work site, and as a safe place to stand when a train is passing. This helps when doing minor work, while needing to keep trains running, by not needing a Hi-railer or transport vehicle blocking the line to transport crew to get to the site.
+
+Maintenance of way equipment in Italy
+
+A track renewal train in Pennsylvania
+
+Railway tracks are generally laid on a bed of stone track ballast or track bed, which in turn is supported by prepared earthworks known as the track formation. The formation comprises the subgrade and a layer of sand or stone dust (often sandwiched in impervious plastic), known as the blanket, which restricts the upward migration of wet clay or silt. There may also be layers of waterproof fabric to prevent water penetrating to the subgrade.  The track and ballast form the permanent way. The foundation may refer to the ballast and formation, i.e. all man-made structures below the tracks.
+
+Some railroads are using asphalt pavement below the ballast in order to keep dirt and moisture from moving into the ballast and spoiling it. The fresh asphalt also serves to stabilize the ballast so it does not move around so easily.[38]
+
+Additional measures are required where the track is laid over permafrost, such as on the Qingzang Railway in Tibet. For example, transverse pipes through the subgrade allow cold air to penetrate the formation and prevent that subgrade from melting.
+
+The sub-grade layers are slightly sloped to one side to help drainage of water.  Rubber sheets may be inserted to help drainage and also protect iron bridgework from being affected by rust.
+
+The technology of rail tracks developed over a long period, starting with primitive timber rails in mines in the 17th century.
+

en/6024.html.txt

@@ -0,0 +1,150 @@
+
+
+North America · South America · Europe · Australia
+
+The track on a railway or railroad, also known as the permanent way, is the structure consisting of the rails, fasteners, railroad ties (sleepers, British English) and ballast (or slab track), plus the underlying subgrade. It enables trains to move by providing a dependable surface for their wheels to roll upon. For clarity it is often referred to as railway track (British English and UIC terminology) or railroad track (predominantly in the United States). Tracks where electric trains or electric trams run are equipped with an electrification system such as an overhead electrical power line or an additional electrified rail.
+
+The term permanent way also refers to the track in addition to lineside structures such as fences.
+
+Notwithstanding modern technical developments, the overwhelmingly dominant track form worldwide consists of flat-bottom steel rails supported on timber or pre-stressed concrete sleepers, which are themselves laid on crushed stone ballast.
+
+Most railroads with heavy traffic utilize continuously welded rails supported by sleepers attached via base plates that spread the load. A plastic or rubber pad is usually placed between the rail and the tie plate where concrete sleepers are used. The rail is usually held down to the sleeper with resilient fastenings, although cut spikes are widely used in North American practice. For much of the 20th century, rail track used softwood timber sleepers and jointed rails, and a considerable extent of this track type remains on secondary and tertiary routes. The rails were typically of flat bottom section fastened to the sleepers with dog spikes through a flat tie plate in North America and Australia, and typically of bullhead section carried in cast iron chairs in British and Irish practice.  The London, Midland and Scottish Railway pioneered the conversion to flat-bottomed rail and the supposed advantage of bullhead rail - that the rail could be turned over and re-used when the top surface had become worn - turned out to be unworkable in practice because the underside was usually ruined by fretting from the chairs.
+
+Jointed rails were used at first because contemporary technology did not offer any alternative. However, the intrinsic weakness in resisting vertical loading results in the ballast becoming depressed and a heavy maintenance workload is imposed to prevent unacceptable geometrical defects at the joints. The joints also needed to be lubricated, and wear at the fishplate (joint bar) mating surfaces needed to be rectified by shimming. For this reason jointed track is not financially appropriate for heavily operated railroads.
+
+Timber sleepers are of many available timbers, and are often treated with creosote, Chromated copper arsenate, or other wood preservatives. Pre-stressed concrete sleepers are often used where timber is scarce and where tonnage or speeds are high. Steel is used in some applications.
+
+The track ballast is customarily crushed stone, and the purpose of this is to support the sleepers and allow some adjustment of their position, while allowing free drainage.
+
+traditional railway track (showing ballast, part of sleeper and fixing mechanisms)
+
+Track of Singapore LRT
+
+Ballastless high-speed track in China
+
+A disadvantage of traditional track structures is the heavy demand for maintenance, particularly surfacing (tamping) and lining to restore the desired track geometry and smoothness of vehicle running. Weakness of the subgrade and drainage deficiencies also lead to heavy maintenance costs. This can be overcome by using ballastless track. In its simplest form this consists of a continuous slab of concrete (like a highway structure) with the rails supported directly on its upper surface (using a resilient pad).
+
+There are a number of proprietary systems, and variations include a continuous reinforced concrete slab, or alternatively the use of pre-cast pre-stressed concrete units laid on a base layer. Many permutations of design have been put forward.
+
+However, ballastless track has a high initial cost, and in the case of existing railroads the upgrade to such requires closure of the route for a long period. Its whole-life cost can be lower because of the reduction in maintenance. Ballastless track is usually considered for new very high speed or very high loading routes, in short extensions that require additional strength (e.g. railway stations), or for localised replacement where there are exceptional maintenance difficulties, for example in tunnels. Most rapid transit lines and rubber-tyred metro systems use ballastless track.[1]
+
+Early railways (c. 1840s) experimented with continuous bearing railtrack, in which the rail was supported along its length, with examples including Brunel's baulk road on the Great Western Railway, as well as use on the Newcastle and North Shields Railway,[2] on the Lancashire and Yorkshire Railway to a design by John Hawkshaw, and elsewhere.[3] Continuous-bearing designs were also promoted by other engineers.[4] The system was tested on the Baltimore and Ohio railway in the 1840s, but was found to be more expensive to maintain than rail with cross sleepers.[5]
+
+This type of track still exists on some bridges on Network Rail where the timber baulks are called waybeams or longitudinal timbers. Generally the speed over such structures is low.[6]
+
+Later applications of continuously supported track include Balfour Beatty's 'embedded slab track', which uses a rounded rectangular rail profile (BB14072) embedded in a slipformed (or pre-cast) concrete base (development 2000s).[7][8] The 'embedded rail structure', used in the Netherlands since 1976, initially used a conventional UIC 54 rail embedded in concrete, and later developed (late 1990s) to use a 'mushroom' shaped SA42 rail profile; a version for light rail using a rail supported in an asphalt concrete–filled steel trough has also been developed (2002).[9]
+
+Modern ladder track can be considered a development of baulk road. Ladder track utilizes sleepers aligned along the same direction as the rails with rung-like gauge restraining cross members. Both ballasted and ballastless types exist.
+
+Modern track typically uses hot-rolled steel with a profile of an asymmetrical rounded I-beam.[10] Unlike some other uses of iron and steel, railway rails are subject to very high stresses and have to be made of very high-quality steel alloy. It took many decades to improve the quality of the materials, including the change from iron to steel. The stronger the rails and the rest of the trackwork, the heavier and faster the trains the track can carry.
+
+Other profiles of rail include: bullhead rail; grooved rail; "flat-bottomed rail" (Vignoles rail or flanged T-rail); bridge rail (inverted U–shaped used in baulk road); and Barlow rail (inverted V).
+
+North American railroads until the mid- to late-20th century used rails 39 feet (12 m) long so they could be carried in gondola cars (open wagons), often 40 feet (12 m) long; as gondola sizes increased, so did rail lengths.
+
+According to the Railway Gazette the planned-but-cancelled 150-kilometre rail line for the Baffinland Iron Mine, on Baffin Island, would have used older carbon steel alloys for its rails, instead of more modern, higher performance alloys, because modern alloy rails can become brittle at very low temperatures.[11]
+
+The earliest rails were made of wood, which wore out quickly. Hardwood such as jarrah and karri were better than softwoods such as fir.  Longitudinal sleepers such as Brunel's baulk road are topped with iron or steel rails that are lighter than they might otherwise be because of the support of the sleepers.
+
+Early North American railroads used iron on top of wooden rails as an economy measure but gave up this method of construction after the iron came loose, began to curl and went into the floors of the coaches. The iron strap rail coming through the floors of the coaches came to be referred to as "snake heads" by early railroaders.[12][13]
+
+Rail is graded by weight over a standard length.  Heavier rail can support greater axle loads and higher train speeds without sustaining damage than lighter rail, but at a greater cost. In North America and the United Kingdom, rail is graded by its linear density in pounds per yard (usually shown as pound or lb), so 130-pound rail would weigh 130 lb/yd (64 kg/m). The usual range is 115 to 141 lb/yd (57 to 70 kg/m). In Europe, rail is graded in kilograms per metre and the usual range is 40 to 60 kg/m (81 to 121 lb/yd). The heaviest rail mass-produced was 155 pounds per yard (77 kg/m) and was rolled for the Pennsylvania Railroad. The United Kingdom is in the process of transition from the imperial to metric rating of rail.[14]
+
+The rails used in rail transport are produced in sections of fixed length. Rail lengths are made as long as possible, as the joints between rails are a source of weakness. Throughout the history of rail production, lengths have increased as manufacturing processes have improved.
+
+The following are lengths of single sections produced by steel mills, without any thermite welding.  Shorter rails may be welded with flashbutt welding, but the following rail lengths are unwelded.
+
+Welding of rails into longer lengths was first introduced around 1893, making train rides quieter and safer. With the introduction of thermite welding after 1899, the process became less labor-intensive and ubiquitous.[20]
+
+Modern production techniques allowed the production of longer unwelded segments.
+
+Newer longer rails tend to be made as simple multiples of older shorter rails, so that old rails can be replaced without cutting.  Some cutting would be needed as slightly longer rails are needed on the outside of sharp curves compared to the rails on the inside.
+
+Rails can be supplied pre-drilled with boltholes for fishplates or without where they will be welded into place. There are usually two or three boltholes at each end.
+
+Rails are produced in fixed lengths and need to be joined end-to-end to make a continuous surface on which trains may run. The traditional method of joining the rails is to bolt them together using metal fishplates (jointbars in the US), producing jointed track. For more modern usage, particularly where higher speeds are required, the lengths of rail may be welded together to form continuous welded rail (CWR).
+
+Jointed track is made using lengths of rail, usually around 20 m (66 ft) long (in the UK) and 39 or 78 ft (12 or 24 m) long (in North America), bolted together using perforated steel plates known as fishplates (UK) or joint bars (North America).
+
+Fishplates are usually 600 mm (2 ft) long, used in pairs either side of the rail ends and bolted together (usually four, but sometimes six bolts per joint). The bolts have alternating orientations so that in the event of a derailment and a wheel flange striking the joint, only some of the bolts will be sheared, reducing the likelihood of the rails misaligning with each other and exacerbating the derailment. This technique is not applied universally; European practice being to have all the bolt heads on the same side of the rail.
+
+Small gaps which function as expansion joints are deliberately left between the rail ends to allow for expansion of the rails in hot weather. European practice was to have the rail joints on both rails adjacent to each other, while North American practice is to stagger them. Because of these small gaps, when trains pass over jointed tracks they make a "clickety-clack" sound. Unless it is well-maintained, jointed track does not have the ride quality of welded rail and is less desirable for high speed trains. However, jointed track is still used in many countries on lower speed lines and sidings, and is used extensively in poorer countries due to the lower construction cost and the simpler equipment required for its installation and maintenance.
+
+A major problem of jointed track is cracking around the bolt holes, which can lead to breaking of the rail head (the running surface). This was the cause of the Hither Green rail crash which caused British Railways to begin converting much of its track to continuous welded rail.
+
+Where track circuits exist for signalling purposes, insulated block joints are required. These compound the weaknesses of ordinary joints. Specially-made glued joints, where all the gaps are filled with epoxy resin, increase the strength again.
+
+As an alternative to the insulated joint, audio frequency track circuits can be employed using a tuned loop formed in approximately 20 m (66 ft) of the rail as part of the blocking circuit.  Some insulated joints are unavoidable within turnouts.
+
+Another alternative is the axle counter, which can reduce the number of track circuits and thus the number of insulated rail joints required.
+
+Most modern railways use continuous welded rail (CWR), sometimes referred to as ribbon rails. In this form of track, the rails are welded together by utilising flash butt welding to form one continuous rail that may be several kilometres long. Because there are few joints, this form of track is very strong, gives a smooth ride, and needs less maintenance; trains can travel on it at higher speeds and with less friction. Welded rails are more expensive to lay than jointed tracks, but have much lower maintenance costs. The first welded track was used in Germany in 1924.[25] and has become common on main lines since the 1950s.
+
+The preferred process of flash butt welding involves an automated track-laying machine running a strong electric current through the touching ends of two unjoined rails. The ends become white hot due to electrical resistance and are then pressed together forming a strong weld. Thermite welding is used to repair or splice together existing CWR segments.  This is a manual process requiring a reaction crucible and form to contain the molten iron. Thermite-bonded joints are seen as less reliable and more prone to fracture or break.[26]
+
+North American practice is to weld 1⁄4 mile (400 m) long segments of rail at a rail facility and load it on a special train to carry it to the job site. This train is designed to carry many segments of rail which are placed so they can slide off their racks to the rear of the train and be attached to the ties (sleepers) in a continuous operation.[27]
+
+If not restrained, rails would lengthen in hot weather and shrink in cold weather. To provide this restraint, the rail is prevented from moving in relation to the sleeper by use of clips or anchors. Attention needs to be paid to compacting the ballast effectively, including under, between, and at the ends of the sleepers, to prevent the sleepers from moving. Anchors are more common for wooden sleepers, whereas most concrete or steel sleepers are fastened to the rail by special clips that resist longitudinal movement of the rail. There is no theoretical limit to how long a welded rail can be. However, if longitudinal and lateral restraint are insufficient, the track could become distorted in hot weather and cause a derailment. Distortion due to heat expansion is known in North America as sun kink, and elsewhere as buckling. In extreme hot weather special inspections are required to monitor sections of track known to be problematic. In North American practice extreme temperature conditions will trigger slow orders to allow for crews to react to buckling or "sun kinks" if encountered.[28]
+
+After new segments of rail are laid, or defective rails replaced (welded-in), the rails can be artificially stressed if the temperature of the rail during laying is cooler than what is desired. The stressing process involves either heating the rails, causing them to expand,[29] or stretching the rails with hydraulic equipment. They are then fastened (clipped) to the sleepers in their expanded form. This process ensures that the rail will not expand much further in subsequent hot weather. In cold weather the rails try to contract, but because they are firmly fastened, cannot do so. In effect, stressed rails are a bit like a piece of stretched elastic firmly fastened down.  In extremely cold weather, rails are heated to prevent "pull aparts".[30]
+
+CWR is laid (including fastening) at a temperature roughly midway between the extremes experienced at that location. (This is known as the "rail neutral temperature".) This installation procedure is intended to prevent tracks from buckling in summer heat or pulling apart in the winter cold. In North America, because broken rails (known as a pull-apart) are typically detected by interruption of the current in the signaling system, they are seen as less of a potential hazard than undetected heat kinks.
+
+Joints are used in the continuous welded rail when necessary, usually for signal circuit gaps. Instead of a joint that passes straight across the rail, the two rail ends are sometimes cut at an angle to give a smoother transition. In extreme cases, such as at the end of long bridges, a breather switch (referred to in North America and Britain as an expansion joint) gives a smooth path for the wheels while allowing the end of one rail to expand relative to the next rail.
+
+A sleeper (tie) is a rectangular object on which the rails are supported and fixed. The sleeper has two main roles: to transfer the loads from the rails to the track ballast and the ground underneath, and to hold the rails to the correct width apart (to maintain the rail gauge). They are generally laid transversely to the rails.
+
+Various methods exist for fixing the rail to the sleeper. Historically spikes gave way to cast iron chairs fixed to the sleeper, more recently springs (such as Pandrol clips) are used to fix the rail to the sleeper chair.
+
+Sometimes rail tracks are designed to be portable and moved from one place to another as required. During construction of the Panama Canal, tracks were moved around excavation works. These track gauge were 5 ft (1,524 mm) and the rolling stock full size.  Portable tracks have often been used in open pit mines. In 1880 in New York City, sections of heavy portable track (along with much other improvised technology) helped in the epic move of the ancient obelisk in Central Park to its final location from the dock where it was unloaded from the cargo ship SS Dessoug.
+
+Cane railways often had permanent tracks for the main lines, with portable tracks serving the canefields themselves.  These tracks were narrow gauge (for example, 2 ft (610 mm)) and the portable track came in straights, curves, and turnouts, rather like on a model railway.[31]
+
+Decauville was a source of many portable light rail tracks, also used for military purposes.
+
+The permanent way is so called because temporary way tracks were often used in the construction of that permanent way.
+
+The geometry of the tracks is three-dimensional by nature, but the standards that express the speed limits and other regulations in the areas of track gauge, alignment, elevation, curvature and track surface are usually expressed in two separate layouts for horizontal and vertical.
+
+Horizontal layout is the track layout on the horizontal plane. This involves the layout of three main track types: tangent track (straight line), curved track, and track transition curve (also called transition spiral or spiral) which connects between a tangent and a curved track.
+
+Vertical layout is the track layout on the vertical plane including the concepts such as crosslevel, cant and gradient.[32][33]
+
+A sidetrack is a railroad track other than siding that is auxiliary to the main track. The word is also used as a verb (without object) to refer to the movement of trains and railcars from the main track to a siding, and in common parlance to refer to giving in to distractions apart from a main subject.[34] Sidetracks are used by railroads to order and organize the flow of rail traffic.
+
+During the early days of rail, there was considerable variation in the gauge used by different systems. Today, 54.8% of the world's railways use a gauge of 1,435 mm (4 ft 8 1⁄2 in), known as standard or international gauge.[35][36] Gauges wider than standard gauge are called broad gauge; narrower, narrow gauge. Some stretches of track are dual gauge, with three (or sometimes four) parallel rails in place of the usual two, to allow trains of two different gauges to use the same track.[37]
+
+Gauge can safely vary over a range.  For example, U.S. federal safety standards allow standard gauge to vary from 4 ft 8 in (1,420 mm) to 4 ft 9 1⁄2 in (1,460 mm) for operation up to 60 mph (97 km/h).
+
+Track needs regular maintenance to remain in good order, especially when high-speed trains are involved. Inadequate maintenance may lead to a "slow order" (North American terminology, or Temporary speed restriction in the United Kingdom) being imposed to avoid accidents (see Slow zone). Track maintenance was at one time hard manual labour, requiring teams of labourers, or trackmen (US: gandy dancers; UK: platelayers; Australia: fettlers), who used lining bars to correct irregularities in horizontal alignment (line) of the track, and tamping and jacks to correct vertical irregularities (surface). Currently, maintenance is facilitated by a variety of specialised machines.
+
+The surface of the head of each of the two rails can be maintained by using a railgrinder.
+
+Common maintenance jobs include changing sleepers, lubricating and adjusting switches, tightening loose track components, and surfacing and lining track to keep straight sections straight and curves within maintenance limits. The process of sleeper and rail replacement can be automated by using a track renewal train.
+
+Spraying ballast with herbicide to prevent weeds growing through and redistributing the ballast is typically done with a special weed killing train.
+
+Over time, ballast is crushed or moved by the weight of trains passing over it, periodically requiring relevelling ("tamping") and eventually to be cleaned or replaced. If this is not done, the tracks may become uneven causing swaying, rough riding and possibly derailments. An alternative to tamping is to lift the rails and sleepers and reinsert the ballast beneath. For this, specialist "stoneblower" trains are used.
+
+Rail inspections utilize nondestructive testing methods to detect internal flaws in the rails. This is done by using specially equipped HiRail trucks, inspection cars, or in some cases handheld inspection devices.
+
+Rails must be replaced before the railhead profile wears to a degree that may trigger a derailment. Worn mainline rails usually have sufficient life remaining to be used on a branch line, siding or stub afterwards and are "cascaded" to those applications.
+
+The environmental conditions along railroad track create a unique railway ecosystem. This is particularly so in the United Kingdom where steam locomotives are only used on special services and vegetation has not been trimmed back so thoroughly. This creates a fire risk in prolonged dry weather.
+
+In the UK, the cess is used by track repair crews to walk to a work site, and as a safe place to stand when a train is passing. This helps when doing minor work, while needing to keep trains running, by not needing a Hi-railer or transport vehicle blocking the line to transport crew to get to the site.
+
+Maintenance of way equipment in Italy
+
+A track renewal train in Pennsylvania
+
+Railway tracks are generally laid on a bed of stone track ballast or track bed, which in turn is supported by prepared earthworks known as the track formation. The formation comprises the subgrade and a layer of sand or stone dust (often sandwiched in impervious plastic), known as the blanket, which restricts the upward migration of wet clay or silt. There may also be layers of waterproof fabric to prevent water penetrating to the subgrade.  The track and ballast form the permanent way. The foundation may refer to the ballast and formation, i.e. all man-made structures below the tracks.
+
+Some railroads are using asphalt pavement below the ballast in order to keep dirt and moisture from moving into the ballast and spoiling it. The fresh asphalt also serves to stabilize the ballast so it does not move around so easily.[38]
+
+Additional measures are required where the track is laid over permafrost, such as on the Qingzang Railway in Tibet. For example, transverse pipes through the subgrade allow cold air to penetrate the formation and prevent that subgrade from melting.
+
+The sub-grade layers are slightly sloped to one side to help drainage of water.  Rubber sheets may be inserted to help drainage and also protect iron bridgework from being affected by rust.
+
+The technology of rail tracks developed over a long period, starting with primitive timber rails in mines in the 17th century.
+

en/6025.html.txt

@@ -0,0 +1,155 @@
+
+
+The Milky Way[a] is the galaxy that contains our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. The term Milky Way is a translation of the Latin via lactea, from the Greek γαλαξίας κύκλος (galaxías kýklos, "milky circle").[19][20][21] From Earth, the Milky Way appears as a band because its disk-shaped structure is viewed from within. Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610. Until the early 1920s, most astronomers thought that the Milky Way contained all the stars in the Universe.[22] Following the 1920 Great Debate between the astronomers Harlow Shapley and Heber Curtis,[23] observations by Edwin Hubble showed that the Milky Way is just one of many galaxies.
+
+The Milky Way is a barred spiral galaxy with an estimated visible diameter between 170,000 and 200,000 light-years (ly).[24][25][26][27] It is estimated to contain 100–400 billion stars[28][29] and at least that number of planets.[30][31] The dark matter halo around the Milky Way may span as much as 2 million light years.[5] The Solar System is located at a radius of about 27,000 light-years from the Galactic Center,[15] on the inner edge of the Orion Arm, one of the spiral-shaped concentrations of gas and dust. The stars in the innermost 10,000 light-years form a bulge and one or more bars that radiate from the bulge. The galactic center is an intense radio source known as Sagittarius A*, a supermassive black hole of 4.100 (± 0.034) million solar masses.
+
+Stars and gases at a wide range of distances from the Galactic Center orbit at approximately 220 kilometers per second. The constant rotation speed contradicts the laws of Keplerian dynamics and suggests that much (about 90%)[32][33] of the mass of the Milky Way is invisible to telescopes, neither emitting nor absorbing electromagnetic radiation. This conjectural mass has been termed "dark matter".[34] The rotational period is about 240 million years at the radius of the Sun.[16] The Milky Way as a whole is moving at a velocity of approximately 600 km per second with respect to extragalactic frames of reference. The oldest stars in the Milky Way are nearly as old as the Universe itself and thus probably formed shortly after the Dark Ages of the Big Bang.[35]
+
+The Milky Way has several satellite galaxies and is part of the Local Group of galaxies, which form part of the Virgo Supercluster, which is itself a component of the Laniakea Supercluster.[36][37]
+
+The Milky Way is visible from Earth as a hazy band of white light, some 30° wide, arching across the night sky.[38] In night sky observing, although all the individual naked-eye stars in the entire sky are part of the Milky Way Galaxy, the term "Milky Way" is limited to this band of light.[39][40] The light originates from the accumulation of unresolved stars and other material located in the direction of the galactic plane. Dark regions within the band, such as the Great Rift and the Coalsack, are areas where interstellar dust blocks light from distant stars. The area of sky that the Milky Way obscures is called the Zone of Avoidance.
+
+The Milky Way has a relatively low surface brightness. Its visibility can be greatly reduced by background light, such as light pollution or moonlight. The sky needs to be darker than about 20.2 magnitude per square arcsecond in order for the Milky Way to be visible.[41] It should be visible if the limiting magnitude is approximately +5.1 or better and shows a great deal of detail at +6.1.[42] This makes the Milky Way difficult to see from brightly lit urban or suburban areas, but very prominent when viewed from rural areas when the Moon is below the horizon.[b] Maps of artificial night sky brightness show that more than one-third of Earth's population cannot see the Milky Way from their homes due to light pollution.[43]
+
+As viewed from Earth, the visible region of the Milky Way's galactic plane occupies an area of the sky that includes 30 constellations.[44] The Galactic Center lies in the direction of Sagittarius, where the Milky Way is brightest. From Sagittarius, the hazy band of white light appears to pass around to the galactic anticenter in Auriga. The band then continues the rest of the way around the sky, back to Sagittarius, dividing the sky into two roughly equal hemispheres.
+
+The galactic plane is inclined by about 60° to the ecliptic (the plane of Earth's orbit). Relative to the celestial equator, it passes as far north as the constellation of Cassiopeia and as far south as the constellation of Crux, indicating the high inclination of Earth's equatorial plane and the plane of the ecliptic, relative to the galactic plane. The north galactic pole is situated at right ascension 12h 49m, declination +27.4° (B1950) near β Comae Berenices, and the south galactic pole is near α Sculptoris. Because of this high inclination, depending on the time of night and year, the arch of the Milky Way may appear relatively low or relatively high in the sky. For observers from latitudes approximately 65° north to 65° south, the Milky Way passes directly overhead twice a day.
+
+The Milky Way is the second-largest galaxy in the Local Group (after the Andromeda Galaxy), with its stellar disk approximately 170,000–200,000 light-years (52–61 kpc) in diameter and, on average, approximately 1,000 ly (0.3 kpc) thick.[6][7] The Milky Way is approximately 890 billion times the mass of the Sun.[45] To compare the relative physical scale of the Milky Way, if the Solar System out to Neptune were the size of a US quarter (24.3 mm (0.955 in)), the Milky Way would be approximately the size of the contiguous United States.[46] There is a ring-like filament of stars rippling above and below the relatively flat galactic plane, wrapping around the Milky Way at a diameter of 150,000–180,000 light-years (46–55 kpc),[47] which may be part of the Milky Way itself.[26]
+
+Estimates of the mass of the Milky Way vary, depending upon the method and data used. The low end of the estimate range is 5.8×1011 solar masses (M☉), somewhat less than that of the Andromeda Galaxy.[48][49][50] Measurements using the Very Long Baseline Array in 2009 found velocities as large as 254 km/s (570,000 mph) for stars at the outer edge of the Milky Way.[51] Because the orbital velocity depends on the total mass inside the orbital radius, this suggests that the Milky Way is more massive, roughly equaling the mass of Andromeda Galaxy at 7×1011 M☉ within 160,000 ly (49 kpc) of its center.[52] In 2010, a measurement of the radial velocity of halo stars found that the mass enclosed within 80 kiloparsecs is 7×1011 M☉.[53] According to a study published in 2014, the mass of the entire Milky Way is estimated to be 8.5×1011 M☉,[54] but this is only half the mass of the Andromeda Galaxy.[54] A recent mass estimate for the Milky Way is 1.29×1012 M☉.[55]
+
+Much of the mass of the Milky Way seems to be dark matter, an unknown and invisible form of matter that interacts gravitationally with ordinary matter. A dark matter halo is conjectured to spread out relatively uniformly to a distance beyond one hundred kiloparsecs (kpc) from the Galactic Center. Mathematical models of the Milky Way suggest that the mass of dark matter is 1–1.5×1012 M☉.[9][10][56] Recent studies indicate a range in mass, as large as 4.5×1012 M☉[57] and as small as 8×1011 M☉.[58] 
+The total mass of all the stars in the Milky Way is estimated to be between 4.6×1010 M☉[59] and 6.43×1010 M☉.[9] In addition to the stars, there is also interstellar gas, comprising 90% hydrogen and 10% helium by mass,[60] with two thirds of the hydrogen found in the atomic form and the remaining one-third as molecular hydrogen.[61] The mass of the Milky Way's interstellar gas is equal to between 10%[61] and 15%[60] of the total mass of its stars. Interstellar dust accounts for an additional 1% of the total mass of the gas.[60]
+
+In March 2019, astronomers reported that the mass of the Milky Way galaxy is 1.5 trillion solar masses within a radius of about 129,000 light-years, over twice as much as was determined in earlier studies, and suggesting that about 90% of the mass of the galaxy is dark matter.[32][33]
+
+The Milky Way contains between 100 and 400 billion stars[62][63] and at least that many planets.[64] An exact figure would depend on counting the number of very-low-mass stars, which are difficult to detect, especially at distances of more than 300 ly (90 pc) from the Sun. As a comparison, the neighboring Andromeda Galaxy contains an estimated one trillion (1012) stars.[65] Perhaps, the Milky Way may contain ten billion white dwarfs, a billion neutron stars, and a hundred million stellar black holes.[c][66][67][68][69] Filling the space between the stars is a disk of gas and dust called the interstellar medium. This disk has at least a comparable extent in radius to the stars,[70] whereas the thickness of the gas layer ranges from hundreds of light-years for the colder gas to thousands of light-years for warmer gas.[71][72]
+
+The disk of stars in the Milky Way does not have a sharp edge beyond which there are no stars. Rather, the concentration of stars decreases with distance from the center of the Milky Way. For reasons that are not understood, beyond a radius of roughly 40,000 ly (13 kpc) from the center, the number of stars per cubic parsec drops much faster with radius.[73] Surrounding the galactic disk is a spherical Galactic Halo of stars and globular clusters that extends farther outward, but is limited in size by the orbits of two Milky Way satellites, the Large and Small Magellanic Clouds, whose closest approach to the Galactic Center is about 180,000 ly (55 kpc).[74] At this distance or beyond, the orbits of most halo objects would be disrupted by the Magellanic Clouds. Hence, such objects would probably be ejected from the vicinity of the Milky Way. The integrated absolute visual magnitude of the Milky Way is estimated to be around −20.9.[75][76][d]
+
+Both gravitational microlensing and planetary transit observations indicate that there may be at least as many planets bound to stars as there are stars in the Milky Way,[30][77] and microlensing measurements indicate that there are more rogue planets not bound to host stars than there are stars.[78][79] The Milky Way contains at least one planet per star, resulting in 100–400 billion planets, according to a January 2013 study of the five-planet star system Kepler-32 with the Kepler space observatory.[31] A different January 2013 analysis of Kepler data estimated that at least 17 billion Earth-sized exoplanets reside in the Milky Way.[80] On November 4, 2013, astronomers reported, based on Kepler space mission data, that there could be as many as 40 billion Earth-sized planets orbiting in the habitable zones of Sun-like stars and red dwarfs within the Milky Way.[81][82][83] 11 billion of these estimated planets may be orbiting Sun-like stars.[84] The nearest exoplanet may be 4.2 light-years away, orbiting the red dwarf Proxima Centauri, according to a 2016 study.[85] Such Earth-sized planets may be more numerous than gas giants.[30] Besides exoplanets, "exocomets", comets beyond the Solar System, have also been detected and may be common in the Milky Way.[86]
+
+In June 2020, astronomers from the University of Nottingham reported the possible existence of over 30 "active communicating intelligent civilizations", or Communicating Extra-Terrestrial Intelligent (CETI) civilizations (none within our current ability to detect due to various reasons including distance or size) in our own Milky Way galaxy, based on the latest astrophysical information.[87][88][89]
+
+360-degree panorama view of the Milky Way (an assembled mosaic of photographs) by ESO, the galactic centre is in the middle of the view, with galactic north up
+
+The Milky Way consists of a bar-shaped core region surrounded by a warped disk of gas, dust and stars.[93][94] The mass distribution within the Milky Way closely resembles the type Sbc in the Hubble classification, which represents spiral galaxies with relatively loosely wound arms.[1] Astronomers first began to suspect that the Milky Way is a barred spiral galaxy, rather than an ordinary spiral galaxy, in the 1960s.[95][96][97] Their suspicions were confirmed by the Spitzer Space Telescope observations in 2005[98] that showed the Milky Way's central bar to be larger than previously thought.
+
+A galactic quadrant, or quadrant of the Milky Way, refers to one of four circular sectors in the division of the Milky Way. In astronomical practice, the delineation of the galactic quadrants is based upon the galactic coordinate system, which places the Sun as the origin of the mapping system.[99]
+
+Quadrants are described using ordinals – for example, "1st galactic quadrant",[100] "second galactic quadrant",[101] or "third quadrant of the Milky Way".[102] Viewing from the north galactic pole with 0 degrees (°) as the ray that runs starting from the Sun and through the Galactic Center, the quadrants are as follows:
+
+The Sun is 25,000–28,000 ly (7.7–8.6 kpc) from the Galactic Center. This value is estimated using geometric-based methods or by measuring selected astronomical objects that serve as standard candles, with different techniques yielding various values within this approximate range.[104][14][15][105][106][107] In the inner few kpc (around 10,000 light-years radius) is a dense concentration of mostly old stars in a roughly spheroidal shape called the bulge.[108] It has been proposed that the Milky Way lacks a bulge formed due to a collision and merger between previous galaxies, and that instead it only has a pseudobulge formed by its central bar.[109] However, confusion in the literature between the (peanut shell)-shaped structure created by instabilities in the bar, versus a possible bulge with an expected half-light radius of 0.5 kpc,[110] abounds.
+
+The Galactic Center is marked by an intense radio source named Sagittarius A* (pronounced Sagittarius A-star). The motion of material around the center indicates that Sagittarius A* harbors a massive, compact object.[111] This concentration of mass is best explained as a supermassive black hole[e][104][112] (SMBH) with an estimated mass of 4.1–4.5 million times the mass of the Sun.[112] The rate of accretion of the SMBH is consistent with an inactive galactic nucleus, being estimated at around 1×10−5 M☉ per year.[113] Observations indicate that there are SMBHs located near the center of most normal galaxies.[114][115]
+
+The nature of the Milky Way's bar is actively debated, with estimates for its half-length and orientation spanning from 1 to 5 kpc (3,000–16,000 ly) and 10–50 degrees relative to the line of sight from Earth to the Galactic Center.[106][107][116] Certain authors advocate that the Milky Way features two distinct bars, one nestled within the other.[117] However, RR Lyrae variables do not trace a prominent Galactic bar.[107][118][119] The bar may be surrounded by a ring called the "5-kpc ring" that contains a large fraction of the molecular hydrogen present in the Milky Way, as well as most of the Milky Way's star formation activity. Viewed from the Andromeda Galaxy, it would be the brightest feature of the Milky Way.[120] X-ray emission from the core is aligned with the massive stars surrounding the central bar[113] and the Galactic ridge.[121]
+
+In 2010, two gigantic spherical bubbles of high energy emission were detected to the north and the south of the Milky Way core, using data from the Fermi Gamma-ray Space Telescope. The diameter of each of the bubbles is about 25,000 light-years (7.7 kpc); they stretch up to Grus and to Virgo on the night-sky of the southern hemisphere.[122][123] Subsequently, observations with the Parkes Telescope at radio frequencies identified polarized emission that is associated with the Fermi bubbles. These observations are best interpreted as a magnetized outflow driven by star formation in the central 640 ly (200 pc) of the Milky Way.[124]
+
+Later, on January 5, 2015, NASA reported observing an X-ray flare 400 times brighter than usual, a record-breaker, from Sagittarius A*. The unusual event may have been caused by the breaking apart of an asteroid falling into the black hole or by the entanglement of magnetic field lines within gas flowing into Sagittarius A*.[92]
+
+Outside the gravitational influence of the Galactic bar, the structure of the interstellar medium and stars in the disk of the Milky Way is organized into four spiral arms.[125] Spiral arms typically contain a higher density of interstellar gas and dust than the Galactic average as well as a greater concentration of star formation, as traced by H II regions[126][127] and molecular clouds.[128]
+
+The Milky Way's spiral structure is uncertain, and there is currently no consensus on the nature of the Milky Way's spiral arms.[91] Perfect logarithmic spiral patterns only crudely describe features near the Sun,[127][129] because galaxies commonly have arms that branch, merge, twist unexpectedly, and feature a degree of irregularity.[107][129][130] The possible scenario of the Sun within a spur / Local arm[127] emphasizes that point and indicates that such features are probably not unique, and exist elsewhere in the Milky Way.[129] Estimates of the pitch angle of the arms range from about 7° to 25°.[70][131] There are thought to be four spiral arms that all start near the Milky Way's center.[132] These are named as follows, with the positions of the arms shown in the image at right:
+
+Two spiral arms, the Scutum–Centaurus arm and the Carina–Sagittarius arm, have tangent points inside the Sun's orbit about the center of the Milky Way. If these arms contain an overdensity of stars compared to the average density of stars in the Galactic disk, it would be detectable by counting the stars near the tangent point. Two surveys of near-infrared light, which is sensitive primarily to red giants and not affected by dust extinction, detected the predicted overabundance in the Scutum–Centaurus arm but not in the Carina–Sagittarius arm: the Scutum–Centaurus Arm contains approximately 30% more red giants than would be expected in the absence of a spiral arm.[131][134] This observation suggests that the Milky Way possesses only two major stellar arms: the Perseus arm and the Scutum–Centaurus arm. The rest of the arms contain excess gas but not excess old stars.[91] In December 2013, astronomers found that the distribution of young stars and star-forming regions matches the four-arm spiral description of the Milky Way.[135][136][137] Thus, the Milky Way appears to have two spiral arms as traced by old stars and four spiral arms as traced by gas and young stars. The explanation for this apparent discrepancy is unclear.[137]
+
+The Near 3 kpc Arm (also called Expanding 3 kpc Arm or simply 3 kpc Arm) was discovered in the 1950s by astronomer van Woerden and collaborators through 21-centimeter radio measurements of HI (atomic hydrogen).[138][139] It was found to be expanding away from the central bulge at more than 50 km/s. It is located in the fourth galactic quadrant at a distance of about 5.2 kpc from the Sun and 3.3 kpc from the Galactic Center. The Far 3 kpc Arm was discovered in 2008 by astronomer Tom Dame (Harvard–Smithsonian CfA). It is located in the first galactic quadrant at a distance of 3 kpc (about 10,000 ly) from the Galactic Center.[139][140]
+
+A simulation published in 2011 suggested that the Milky Way may have obtained its spiral arm structure as a result of repeated collisions with the Sagittarius Dwarf Elliptical Galaxy.[141]
+
+It has been suggested that the Milky Way contains two different spiral patterns: an inner one, formed by the Sagittarius arm, that rotates fast and an outer one, formed by the Carina and Perseus arms, whose rotation velocity is slower and whose arms are tightly wound. In this scenario, suggested by numerical simulations of the dynamics of the different spiral arms, the outer pattern would form an outer pseudoring,[142] and the two patterns would be connected by the Cygnus arm.[143]
+
+Outside of the major spiral arms is the Monoceros Ring (or Outer Ring), a ring of gas and stars torn from other galaxies billions of years ago. However, several members of the scientific community recently restated their position affirming the Monoceros structure is nothing more than an over-density produced by the flared and warped thick disk of the Milky Way.[144] The structure of the Milky Way's disk is warped along an "S" curve.[145]
+
+The Galactic disk is surrounded by a spheroidal halo of old stars and globular clusters, of which 90% lie within 100,000 light-years (30 kpc) of the Galactic Center.[146] However, a few globular clusters have been found farther, such as PAL 4 and AM1 at more than 200,000 light-years from the Galactic Center. About 40% of the Milky Way's clusters are on retrograde orbits, which means they move in the opposite direction from the Milky Way rotation.[147] The globular clusters can follow rosette orbits about the Milky Way, in contrast to the elliptical orbit of a planet around a star.[148]
+
+Although the disk contains dust that obscures the view in some wavelengths, the halo component does not. Active star formation takes place in the disk (especially in the spiral arms, which represent areas of high density), but does not take place in the halo, as there is little cool gas to collapse into stars.[16] Open clusters are also located primarily in the disk.[149]
+
+Discoveries in the early 21st century have added dimension to the knowledge of the Milky Way's structure. With the discovery that the disk of the Andromeda Galaxy (M31) extends much farther than previously thought,[150] the possibility of the disk of the Milky Way extending farther is apparent, and this is supported by evidence from the discovery of the Outer Arm extension of the Cygnus Arm[133][151] and of a similar extension of the Scutum–Centaurus Arm.[152] With the discovery of the Sagittarius Dwarf Elliptical Galaxy came the discovery of a ribbon of galactic debris as the polar orbit of the dwarf and its interaction with the Milky Way tears it apart. Similarly, with the discovery of the Canis Major Dwarf Galaxy, it was found that a ring of galactic debris from its interaction with the Milky Way encircles the Galactic disk.
+
+The Sloan Digital Sky Survey of the northern sky shows a huge and diffuse structure (spread out across an area around 5,000 times the size of a full moon) within the Milky Way that does not seem to fit within current models. The collection of stars rises close to perpendicular to the plane of the spiral arms of the Milky Way. The proposed likely interpretation is that a dwarf galaxy is merging with the Milky Way. This galaxy is tentatively named the Virgo Stellar Stream and is found in the direction of Virgo about 30,000 light-years (9 kpc) away.[153]
+
+In addition to the stellar halo, the Chandra X-ray Observatory, XMM-Newton, and Suzaku have provided evidence that there is a gaseous halo with a large amount of hot gas. The halo extends for hundreds of thousand of light-years, much farther than the stellar halo and close to the distance of the Large and Small Magellanic Clouds. The mass of this hot halo is nearly equivalent to the mass of the Milky Way itself.[154][155][156] The temperature of this halo gas is between 1 and 2.5 million K (1.8 and 4.5 million °F).[157]
+
+Observations of distant galaxies indicate that the Universe had about one-sixth as much baryonic (ordinary) matter as dark matter when it was just a few billion years old. However, only about half of those baryons are accounted for in the modern Universe based on observations of nearby galaxies like the Milky Way.[158] If the finding that the mass of the halo is comparable to the mass of the Milky Way is confirmed, it could be the identity of the missing baryons around the Milky Way.[158]
+
+The Sun is near the inner rim of the Orion Arm, within the Local Fluff of the Local Bubble, and in the Gould Belt. Based upon studies of stellar orbits around Sgr A* by Gillessen and associates (2016), the Sun lies at an estimated distance of 27.14 ± 0.46 kly (8.32 ± 0.14 kpc)[15] from the Galactic Center. Boehle and associates (2016) found a smaller value of 25.64 ± 0.46 kly (7.86 ± 0.14 kpc), also using a star orbit analysis.[14] The Sun is currently 5–30 parsecs (16–98 ly) above, or north of, the central plane of the Galactic disk.[159] The distance between the local arm and the next arm out, the Perseus Arm, is about 2,000 parsecs (6,500 ly).[160] The Sun, and thus the Solar System, is located in the Milky Way's galactic habitable zone.
+
+There are about 208 stars brighter than absolute magnitude 8.5 within a sphere with a radius of 15 parsecs (49 ly) from the Sun, giving a density of one star per 69 cubic parsecs, or one star per 2,360 cubic light-years (from List of nearest bright stars). On the other hand, there are 64 known stars (of any magnitude, not counting 4 brown dwarfs) within 5 parsecs (16 ly) of the Sun, giving a density of about one star per 8.2 cubic parsecs, or one per 284 cubic light-years (from List of nearest stars). This illustrates the fact that there are far more faint stars than bright stars: in the entire sky, there are about 500 stars brighter than apparent magnitude 4 but 15.5 million stars brighter than apparent magnitude 14.[161]
+
+The apex of the Sun's way, or the solar apex, is the direction that the Sun travels through space in the Milky Way. The general direction of the Sun's Galactic motion is towards the star Vega near the constellation of Hercules, at an angle of roughly 60 sky degrees to the direction of the Galactic Center. The Sun's orbit about the Milky Way is expected to be roughly elliptical with the addition of perturbations due to the Galactic spiral arms and non-uniform mass distributions. In addition, the Sun passes through the Galactic plane approximately 2.7 times per orbit.[162] This is very similar to how a simple harmonic oscillator works with no drag force (damping) term. These oscillations were until recently thought to coincide with mass lifeform extinction periods on Earth.[163] However, a reanalysis of the effects of the Sun's transit through the spiral structure based on CO data has failed to find a correlation.[164]
+
+It takes the Solar System about 240 million years to complete one orbit of the Milky Way (a galactic year),[16] so the Sun is thought to have completed 18–20 orbits during its lifetime and 1/1250 of a revolution since the origin of humans. The orbital speed of the Solar System about the center of the Milky Way is approximately 220 km/s (490,000 mph) or 0.073% of the speed of light. The Sun moves through the heliosphere at 84,000 km/h (52,000 mph). At this speed, it takes around 1,400 years for the Solar System to travel a distance of 1 light-year, or 8 days to travel 1 AU (astronomical unit).[165] The Solar System is headed in the direction of the zodiacal constellation Scorpius, which follows the ecliptic.[166]
+
+The stars and gas in the Milky Way rotate about its center differentially, meaning that the rotation period varies with location. As is typical for spiral galaxies, the orbital speed of most stars in the Milky Way does not depend strongly on their distance from the center. Away from the central bulge or outer rim, the typical stellar orbital speed is between 210 ± 10 km/s (470,000 ± 22,000 mph).[169] Hence the orbital period of the typical star is directly proportional only to the length of the path traveled. This is unlike the situation within the Solar System, where two-body gravitational dynamics dominate, and different orbits have significantly different velocities associated with them. The rotation curve (shown in the figure) describes this rotation. Toward the center of the Milky Way the orbit speeds are too low, whereas beyond 7 kpcs the speeds are too high to match what would be expected from the universal law of gravitation.
+
+If the Milky Way contained only the mass observed in stars, gas, and other baryonic (ordinary) matter, the rotation speed would decrease with distance from the center. However, the observed curve is relatively flat, indicating that there is additional mass that cannot be detected directly with electromagnetic radiation. This inconsistency is attributed to dark matter.[34] The rotation curve of the Milky Way agrees with the universal rotation curve of spiral galaxies, the best evidence for the existence of dark matter in galaxies. Alternatively, a minority of astronomers propose that a modification of the law of gravity may explain the observed rotation curve.[170]
+
+The Milky Way began as one or several small overdensities in the mass distribution in the Universe shortly after the Big Bang.[171] Some of these overdensities were the seeds of globular clusters in which the oldest remaining stars in what is now the Milky Way formed. Nearly half the matter in the Milky Way may have come from other distant galaxies.[171] Nonetheless, these stars and clusters now comprise the stellar halo of the Milky Way. Within a few billion years of the birth of the first stars, the mass of the Milky Way was large enough so that it was spinning relatively quickly. Due to conservation of angular momentum, this led the gaseous interstellar medium to collapse from a roughly spheroidal shape to a disk. Therefore, later generations of stars formed in this spiral disk. Most younger stars, including the Sun, are observed to be in the disk.[172][173]
+
+Since the first stars began to form, the Milky Way has grown through both galaxy mergers (particularly early in the Milky Way's growth) and accretion of gas directly from the Galactic halo.[173] The Milky Way is currently accreting material from several small galaxies, including two of its largest satellite galaxies, the Large and Small Magellanic Clouds, through the Magellanic Stream. Direct accretion of gas is observed in high-velocity clouds like the Smith Cloud.[174][175] However, properties of the Milky Way such as stellar mass, angular momentum, and metallicity in its outermost regions suggest it has undergone no mergers with large galaxies in the last 10 billion years. This lack of recent major mergers is unusual among similar spiral galaxies; its neighbour the Andromeda Galaxy appears to have a more typical history shaped by more recent mergers with relatively large galaxies.[176][177]
+
+According to recent studies, the Milky Way as well as the Andromeda Galaxy lie in what in the galaxy color–magnitude diagram is known as the "green valley", a region populated by galaxies in transition from the "blue cloud" (galaxies actively forming new stars) to the "red sequence" (galaxies that lack star formation). Star-formation activity in green valley galaxies is slowing as they run out of star-forming gas in the interstellar medium. In simulated galaxies with similar properties, star formation will typically have been extinguished within about five billion years from now, even accounting for the expected, short-term increase in the rate of star formation due to the collision between both the Milky Way and the Andromeda Galaxy.[178] In fact, measurements of other galaxies similar to the Milky Way suggest it is among the reddest and brightest spiral galaxies that are still forming new stars and it is just slightly bluer than the bluest red sequence galaxies.[179]
+
+Globular clusters are among the oldest objects in the Milky Way, which thus set a lower limit on the age of the Milky Way. The ages of individual stars in the Milky Way can be estimated by measuring the abundance of long-lived radioactive elements such as thorium-232 and uranium-238, then comparing the results to estimates of their original abundance, a technique called nucleocosmochronology. These yield values of about 12.5 ± 3 billion years for CS 31082-001[181] and 13.8 ± 4 billion years for BD +17° 3248.[182] Once a white dwarf is formed, it begins to undergo radiative cooling and the surface temperature steadily drops. By measuring the temperatures of the coolest of these white dwarfs and comparing them to their expected initial temperature, an age estimate can be made. With this technique, the age of the globular cluster M4 was estimated as 12.7 ± 0.7 billion years. Age estimates of the oldest of these clusters gives a best fit estimate of 12.6 billion years, and a 95% confidence upper limit of 16 billion years.[183]
+
+In November 2018, astronomers reported the discovery of one of the oldest stars in the universe. About 13.5 billion-years-old, 2MASS J18082002-5104378 B is a tiny ultra metal-poor (UMP) star made almost entirely of materials released from the Big Bang, and is possibly one of the very first stars. The discovery of the star in the Milky Way galaxy suggests that the galaxy may be at least 3 billion years older than previously thought.[184][185][186]
+
+Several individual stars have been found in the Milky Way's halo with measured ages very close to the 13.80-billion-year age of the Universe. In 2007, a star in the galactic halo, HE 1523-0901, was estimated to be about 13.2 billion years old. As the oldest known object in the Milky Way at that time, this measurement placed a lower limit on the age of the Milky Way.[187] This estimate was made using the UV-Visual Echelle Spectrograph of the Very Large Telescope to measure the relative strengths of spectral lines caused by the presence of thorium and other elements created by the R-process. The line strengths yield abundances of different elemental isotopes, from which an estimate of the age of the star can be derived using nucleocosmochronology.[187] Another star, HD 140283, is 14.5 ± 0.7 billion years old.[35][188]
+
+According to observations utilizing adaptive optics to correct for Earth's atmospheric distortion, stars in the galaxy's bulge date to about 12.8 billion years old.[189]
+
+The age of stars in the galactic thin disk has also been estimated using nucleocosmochronology. Measurements of thin disk stars yield an estimate that the thin disk formed 8.8 ± 1.7 billion years ago. These measurements suggest there was a hiatus of almost 5 billion years between the formation of the galactic halo and the thin disk.[190] Recent analysis of the chemical signatures of thousands of stars suggests that stellar formation might have dropped by an order of magnitude at the time of disk formation, 10 to 8 billion years ago, when interstellar gas was too hot to form new stars at the same rate as before.[191]
+
+The satellite galaxies surrounding the Milky way are not randomly distributed but seemed to be the result of a break-up of some larger system producing a ring structure 500,000 light-years in diameter and 50,000 light-years wide.[192] Close encounters between galaxies, like that expected in 4 billion years with the Andromeda Galaxy rips off huge tails of gas, which, over time can coalesce to form dwarf galaxies in a ring at an arbitrary angle to the main disc.[193]
+
+The Milky Way and the Andromeda Galaxy are a binary system of giant spiral galaxies belonging to a group of 50 closely bound galaxies known as the Local Group, surrounded by a Local Void, itself being part of the Virgo Supercluster. Surrounding the Virgo Supercluster are a number of voids, devoid of many galaxies, the Microscopium Void to the "north", the Sculptor Void to the "left", the Bootes Void to the "right" and the Canes-Major Void to the South. These voids change shape over time, creating filamentous structures of galaxies. The Virgo Supercluster, for instance, is being drawn towards the Great Attractor,[194] which in turn forms part of a greater structure, called Laniakea.[195]
+
+Two smaller galaxies and a number of dwarf galaxies in the Local Group orbit the Milky Way. The largest of these is the Large Magellanic Cloud with a diameter of 14,000 light-years. It has a close companion, the Small Magellanic Cloud. The Magellanic Stream is a stream of neutral hydrogen gas extending from these two small galaxies across 100° of the sky. The stream is thought to have been dragged from the Magellanic Clouds in tidal interactions with the Milky Way.[196] Some of the dwarf galaxies orbiting the Milky Way are Canis Major Dwarf (the closest), Sagittarius Dwarf Elliptical Galaxy, Ursa Minor Dwarf, Sculptor Dwarf, Sextans Dwarf, Fornax Dwarf, and Leo I Dwarf. The smallest dwarf galaxies of the Milky Way are only 500 light-years in diameter. These include Carina Dwarf, Draco Dwarf, and Leo II Dwarf. There may still be undetected dwarf galaxies that are dynamically bound to the Milky Way, which is supported by the detection of nine new satellites of the Milky Way in a relatively small patch of the night sky in 2015.[197] There are also some dwarf galaxies that have already been absorbed by the Milky Way, such as the progenitor of Omega Centauri.[198]
+
+In 2014 researchers reported that most satellite galaxies of the Milky Way lie in a very large disk and orbit in the same direction.[199] This came as a surprise: according to standard cosmology, the satellite galaxies should form in dark matter halos, and they should be widely distributed and moving in random directions. This discrepancy is still not fully explained.[200]
+
+In January 2006, researchers reported that the heretofore unexplained warp in the disk of the Milky Way has now been mapped and found to be a ripple or vibration set up by the Large and Small Magellanic Clouds as they orbit the Milky Way, causing vibrations when they pass through its edges. Previously, these two galaxies, at around 2% of the mass of the Milky Way, were considered too small to influence the Milky Way. However, in a computer model, the movement of these two galaxies creates a dark matter wake that amplifies their influence on the larger Milky Way.[201]
+
+Current measurements suggest the Andromeda Galaxy is approaching us at 100 to 140 km/s (220,000 to 310,000 mph). In 3 to 4 billion years, there may be an Andromeda–Milky Way collision, depending on the importance of unknown lateral components to the galaxies' relative motion. If they collide, the chance of individual stars colliding with each other is extremely low, but instead the two galaxies will merge to form a single elliptical galaxy or perhaps a large disk galaxy[202] over the course of about a billion years.[203]
+
+Although special relativity states that there is no "preferred" inertial frame of reference in space with which to compare the Milky Way, the Milky Way does have a velocity with respect to cosmological frames of reference.
+
+One such frame of reference is the Hubble flow, the apparent motions of galaxy clusters due to the expansion of space. Individual galaxies, including the Milky Way, have peculiar velocities relative to the average flow. Thus, to compare the Milky Way to the Hubble flow, one must consider a volume large enough so that the expansion of the Universe dominates over local, random motions. A large enough volume means that the mean motion of galaxies within this volume is equal to the Hubble flow. Astronomers believe the Milky Way is moving at approximately 630 km/s (1,400,000 mph) with respect to this local co-moving frame of reference.[204] The Milky Way is moving in the general direction of the Great Attractor and other galaxy clusters, including the Shapley supercluster, behind it.[205] The Local Group (a cluster of gravitationally bound galaxies containing, among others, the Milky Way and the Andromeda Galaxy) is part of a supercluster called the Local Supercluster, centered near the Virgo Cluster: although they are moving away from each other at 967 km/s (2,160,000 mph) as part of the Hubble flow, this velocity is less than would be expected given the 16.8 million pc distance due to the gravitational attraction between the Local Group and the Virgo Cluster.[206]
+
+Another reference frame is provided by the cosmic microwave background (CMB). The Milky Way is moving at 552 ± 6 km/s (1,235,000 ± 13,000 mph)[18] with respect to the photons of the CMB, toward 10.5 right ascension, −24° declination (J2000 epoch, near the center of Hydra). This motion is observed by satellites such as the Cosmic Background Explorer (COBE) and the Wilkinson Microwave Anisotropy Probe (WMAP) as a dipole contribution to the CMB, as photons in equilibrium in the CMB frame get blue-shifted in the direction of the motion and red-shifted in the opposite direction.[18]
+
+In the Babylonian epic poem Enûma Eliš, the Milky Way is created from the severed tail of the primeval salt water dragoness Tiamat, set in the sky by Marduk, the Babylonian national god, after slaying her.[207][208] This story was once thought to have been based on an older Sumerian version in which Tiamat is instead slain by Enlil of Nippur,[209][210] but is now thought to be purely an invention of Babylonian propagandists with the intention to show Marduk as superior to the Sumerian deities.[210]
+
+Llys Dôn (literally "The Court of Dôn") is the traditional Welsh name for the constellation Cassiopeia. At least three of Dôn's children also have astronomical associations: Caer Gwydion ("The fortress of Gwydion") is the traditional Welsh name for the Milky Way,[211][212] and Caer Arianrhod ("The Fortress of Arianrhod") being the constellation of Corona Borealis.[citation needed]
+
+In western culture, the name "Milky Way" is derived from its appearance as a dim un-resolved "milky" glowing band arching across the night sky. The term is a translation of the Classical Latin via lactea, in turn derived from the Hellenistic Greek γαλαξίας, short for γαλαξίας κύκλος (galaxías kýklos, "milky circle"). The Ancient Greek γαλαξίας (galaxias) – from root γαλακτ-, γάλα ("milk") + -ίας (forming adjectives) – is also the root of "galaxy", the name for our, and later all such, collections of stars.[19][213][214][215]
+
+In Greek mythology, the Milky Way was formed after the trickster god Hermes suckled the infant Heracles at the breast of Hera, the queen of the gods, while she was asleep.[216][217] When Hera awoke, she tore Heracles away from her breast and splattered her breast milk across the heavens.[216][217] In another version of the story, Athena, the patron goddess of heroes, tricked Hera into suckling Heracles voluntarily,[216][217] but he bit her nipple so hard that she flung him away, spraying milk everywhere.[216][217]
+
+The Milky Way, or "milk circle", was just one of 11 "circles" the Greeks identified in the sky, others being the zodiac, the meridian, the horizon, the equator, the tropics of Cancer and Capricorn, Arctic and Antarctic circles, and two colure circles passing through both poles.[218]
+
+In Meteorologica (DK 59 A80), Aristotle (384–322 BC) wrote that the Greek philosophers Anaxagoras (c. 500–428 BC) and Democritus (460–370 BC) proposed that the Milky Way might consist of distant stars.[219] However, Aristotle himself believed the Milky Way to be caused by "the ignition of the fiery exhalation of some stars which were large, numerous and close together"[220] and that the "ignition takes place in the upper part of the atmosphere, in the region of the world which is continuous with the heavenly motions."[221][222] The Neoplatonist philosopher Olympiodorus the Younger (c. 495–570 AD) criticized this view, arguing that if the Milky Way were sublunary, it should appear different at different times and places on Earth, and that it should have parallax, which it does not. In his view, the Milky Way is celestial. This idea would be influential later in the Islamic world.[223]
+
+The Persian astronomer Abū Rayhān al-Bīrūnī (973–1048) proposed that the Milky Way is "a collection of countless fragments of the nature of nebulous stars".[224] The Andalusian astronomer Avempace (d 1138) proposed the Milky Way to be made up of many stars but appears to be a continuous image due to the effect of refraction in Earth's atmosphere, citing his observation of a conjunction of Jupiter and Mars in 1106 or 1107 as evidence.[222] Ibn Qayyim Al-Jawziyya (1292–1350) proposed that the Milky Way is "a myriad of tiny stars packed together in the sphere of the fixed stars" and that these stars are larger than planets.[225]
+
+According to Jamil Ragep, the Persian astronomer Naṣīr al-Dīn al-Ṭūsī (1201–1274) in his Tadhkira writes:
+"The Milky Way, i.e. the Galaxy, is made up of a very large number of small, tightly clustered stars, which, on account of their concentration and smallness, seem to be cloudy patches. Because of this, it was likened to milk in color."[226]
+
+Proof of the Milky Way consisting of many stars came in 1610 when Galileo Galilei used a telescope to study the Milky Way and discovered that it is composed of a huge number of faint stars.[227][228] In a treatise in 1755, Immanuel Kant, drawing on earlier work by Thomas Wright,[229] speculated (correctly) that the Milky Way might be a rotating body of a huge number of stars, held together by gravitational forces akin to the Solar System but on much larger scales.[230] The resulting disk of stars would be seen as a band on the sky from our perspective inside the disk. Wright and Kant also conjectured that some of the nebulae visible in the night sky might be separate "galaxies" themselves, similar to our own. Kant referred to both the Milky Way and the "extragalactic nebulae" as "island universes", a term still current up to the 1930s.[231][232][233]
+
+The first attempt to describe the shape of the Milky Way and the position of the Sun within it was carried out by William Herschel in 1785 by carefully counting the number of stars in different regions of the visible sky. He produced a diagram of the shape of the Milky Way with the Solar System close to the center.[234]
+
+In 1845, Lord Rosse constructed a new telescope and was able to distinguish between elliptical and spiral-shaped nebulae. He also managed to make out individual point sources in some of these nebulae, lending credence to Kant's earlier conjecture.[235][236]
+
+In 1904, studying the proper motions of stars, Jacobus Kapteyn reported that these were not random, as it was believed in that time; stars could be divided into two streams, moving in nearly opposite directions.[237]  It was later realized that Kapteyn's data had been the first evidence of the rotation of our Galaxy,[238] which ultimately led to the finding of galactic rotation by Bertil Lindblad and Jan Oort.
+
+In 1917, Heber Curtis had observed the nova S Andromedae within the Great Andromeda Nebula (Messier object 31). Searching the photographic record, he found 11 more novae. Curtis noticed that these novae were, on average, 10 magnitudes fainter than those that occurred within the Milky Way. As a result, he was able to come up with a distance estimate of 150,000 parsecs. He became a proponent of the "island universes" hypothesis, which held that the spiral nebulae were independent galaxies.[239][240] In 1920 the Great Debate took place between Harlow Shapley and Heber Curtis, concerning the nature of the Milky Way, spiral nebulae, and the dimensions of the Universe. To support his claim that the Great Andromeda Nebula is an external galaxy, Curtis noted the appearance of dark lanes resembling the dust clouds in the Milky Way, as well as the significant Doppler shift.[241]
+
+The controversy was conclusively settled by Edwin Hubble in the early 1920s using the Mount Wilson observatory 2.5 m (100 in) Hooker telescope. With the light-gathering power of this new telescope, he was able to produce astronomical photographs that resolved the outer parts of some spiral nebulae as collections of individual stars. He was also able to identify some Cepheid variables that he could use as a benchmark to estimate the distance to the nebulae. He found that the Andromeda Nebula is 275,000 parsecs from the Sun, far too distant to be part of the Milky Way.[242][243]
+
+The ESA spacecraft Gaia provides distance estimates by determining the parallax of a billion stars and is mapping the Milky Way with four planned releases of maps in 2016, 2018, 2021 and 2024.[244][245] A study in 2020 concluded that Gaia detected a wobbling motion of the galaxy, which might be caused by "torques from a misalignment of the disc's rotation axis with respect to the principle axis of a non-spherical halo, or from accreted matter in the halo acquired during late infall, or from nearby, interacting satellite galaxies and their consequent tides".[246]

en/6026.html.txt

@@ -0,0 +1,155 @@
+
+
+The Milky Way[a] is the galaxy that contains our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. The term Milky Way is a translation of the Latin via lactea, from the Greek γαλαξίας κύκλος (galaxías kýklos, "milky circle").[19][20][21] From Earth, the Milky Way appears as a band because its disk-shaped structure is viewed from within. Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610. Until the early 1920s, most astronomers thought that the Milky Way contained all the stars in the Universe.[22] Following the 1920 Great Debate between the astronomers Harlow Shapley and Heber Curtis,[23] observations by Edwin Hubble showed that the Milky Way is just one of many galaxies.
+
+The Milky Way is a barred spiral galaxy with an estimated visible diameter between 170,000 and 200,000 light-years (ly).[24][25][26][27] It is estimated to contain 100–400 billion stars[28][29] and at least that number of planets.[30][31] The dark matter halo around the Milky Way may span as much as 2 million light years.[5] The Solar System is located at a radius of about 27,000 light-years from the Galactic Center,[15] on the inner edge of the Orion Arm, one of the spiral-shaped concentrations of gas and dust. The stars in the innermost 10,000 light-years form a bulge and one or more bars that radiate from the bulge. The galactic center is an intense radio source known as Sagittarius A*, a supermassive black hole of 4.100 (± 0.034) million solar masses.
+
+Stars and gases at a wide range of distances from the Galactic Center orbit at approximately 220 kilometers per second. The constant rotation speed contradicts the laws of Keplerian dynamics and suggests that much (about 90%)[32][33] of the mass of the Milky Way is invisible to telescopes, neither emitting nor absorbing electromagnetic radiation. This conjectural mass has been termed "dark matter".[34] The rotational period is about 240 million years at the radius of the Sun.[16] The Milky Way as a whole is moving at a velocity of approximately 600 km per second with respect to extragalactic frames of reference. The oldest stars in the Milky Way are nearly as old as the Universe itself and thus probably formed shortly after the Dark Ages of the Big Bang.[35]
+
+The Milky Way has several satellite galaxies and is part of the Local Group of galaxies, which form part of the Virgo Supercluster, which is itself a component of the Laniakea Supercluster.[36][37]
+
+The Milky Way is visible from Earth as a hazy band of white light, some 30° wide, arching across the night sky.[38] In night sky observing, although all the individual naked-eye stars in the entire sky are part of the Milky Way Galaxy, the term "Milky Way" is limited to this band of light.[39][40] The light originates from the accumulation of unresolved stars and other material located in the direction of the galactic plane. Dark regions within the band, such as the Great Rift and the Coalsack, are areas where interstellar dust blocks light from distant stars. The area of sky that the Milky Way obscures is called the Zone of Avoidance.
+
+The Milky Way has a relatively low surface brightness. Its visibility can be greatly reduced by background light, such as light pollution or moonlight. The sky needs to be darker than about 20.2 magnitude per square arcsecond in order for the Milky Way to be visible.[41] It should be visible if the limiting magnitude is approximately +5.1 or better and shows a great deal of detail at +6.1.[42] This makes the Milky Way difficult to see from brightly lit urban or suburban areas, but very prominent when viewed from rural areas when the Moon is below the horizon.[b] Maps of artificial night sky brightness show that more than one-third of Earth's population cannot see the Milky Way from their homes due to light pollution.[43]
+
+As viewed from Earth, the visible region of the Milky Way's galactic plane occupies an area of the sky that includes 30 constellations.[44] The Galactic Center lies in the direction of Sagittarius, where the Milky Way is brightest. From Sagittarius, the hazy band of white light appears to pass around to the galactic anticenter in Auriga. The band then continues the rest of the way around the sky, back to Sagittarius, dividing the sky into two roughly equal hemispheres.
+
+The galactic plane is inclined by about 60° to the ecliptic (the plane of Earth's orbit). Relative to the celestial equator, it passes as far north as the constellation of Cassiopeia and as far south as the constellation of Crux, indicating the high inclination of Earth's equatorial plane and the plane of the ecliptic, relative to the galactic plane. The north galactic pole is situated at right ascension 12h 49m, declination +27.4° (B1950) near β Comae Berenices, and the south galactic pole is near α Sculptoris. Because of this high inclination, depending on the time of night and year, the arch of the Milky Way may appear relatively low or relatively high in the sky. For observers from latitudes approximately 65° north to 65° south, the Milky Way passes directly overhead twice a day.
+
+The Milky Way is the second-largest galaxy in the Local Group (after the Andromeda Galaxy), with its stellar disk approximately 170,000–200,000 light-years (52–61 kpc) in diameter and, on average, approximately 1,000 ly (0.3 kpc) thick.[6][7] The Milky Way is approximately 890 billion times the mass of the Sun.[45] To compare the relative physical scale of the Milky Way, if the Solar System out to Neptune were the size of a US quarter (24.3 mm (0.955 in)), the Milky Way would be approximately the size of the contiguous United States.[46] There is a ring-like filament of stars rippling above and below the relatively flat galactic plane, wrapping around the Milky Way at a diameter of 150,000–180,000 light-years (46–55 kpc),[47] which may be part of the Milky Way itself.[26]
+
+Estimates of the mass of the Milky Way vary, depending upon the method and data used. The low end of the estimate range is 5.8×1011 solar masses (M☉), somewhat less than that of the Andromeda Galaxy.[48][49][50] Measurements using the Very Long Baseline Array in 2009 found velocities as large as 254 km/s (570,000 mph) for stars at the outer edge of the Milky Way.[51] Because the orbital velocity depends on the total mass inside the orbital radius, this suggests that the Milky Way is more massive, roughly equaling the mass of Andromeda Galaxy at 7×1011 M☉ within 160,000 ly (49 kpc) of its center.[52] In 2010, a measurement of the radial velocity of halo stars found that the mass enclosed within 80 kiloparsecs is 7×1011 M☉.[53] According to a study published in 2014, the mass of the entire Milky Way is estimated to be 8.5×1011 M☉,[54] but this is only half the mass of the Andromeda Galaxy.[54] A recent mass estimate for the Milky Way is 1.29×1012 M☉.[55]
+
+Much of the mass of the Milky Way seems to be dark matter, an unknown and invisible form of matter that interacts gravitationally with ordinary matter. A dark matter halo is conjectured to spread out relatively uniformly to a distance beyond one hundred kiloparsecs (kpc) from the Galactic Center. Mathematical models of the Milky Way suggest that the mass of dark matter is 1–1.5×1012 M☉.[9][10][56] Recent studies indicate a range in mass, as large as 4.5×1012 M☉[57] and as small as 8×1011 M☉.[58] 
+The total mass of all the stars in the Milky Way is estimated to be between 4.6×1010 M☉[59] and 6.43×1010 M☉.[9] In addition to the stars, there is also interstellar gas, comprising 90% hydrogen and 10% helium by mass,[60] with two thirds of the hydrogen found in the atomic form and the remaining one-third as molecular hydrogen.[61] The mass of the Milky Way's interstellar gas is equal to between 10%[61] and 15%[60] of the total mass of its stars. Interstellar dust accounts for an additional 1% of the total mass of the gas.[60]
+
+In March 2019, astronomers reported that the mass of the Milky Way galaxy is 1.5 trillion solar masses within a radius of about 129,000 light-years, over twice as much as was determined in earlier studies, and suggesting that about 90% of the mass of the galaxy is dark matter.[32][33]
+
+The Milky Way contains between 100 and 400 billion stars[62][63] and at least that many planets.[64] An exact figure would depend on counting the number of very-low-mass stars, which are difficult to detect, especially at distances of more than 300 ly (90 pc) from the Sun. As a comparison, the neighboring Andromeda Galaxy contains an estimated one trillion (1012) stars.[65] Perhaps, the Milky Way may contain ten billion white dwarfs, a billion neutron stars, and a hundred million stellar black holes.[c][66][67][68][69] Filling the space between the stars is a disk of gas and dust called the interstellar medium. This disk has at least a comparable extent in radius to the stars,[70] whereas the thickness of the gas layer ranges from hundreds of light-years for the colder gas to thousands of light-years for warmer gas.[71][72]
+
+The disk of stars in the Milky Way does not have a sharp edge beyond which there are no stars. Rather, the concentration of stars decreases with distance from the center of the Milky Way. For reasons that are not understood, beyond a radius of roughly 40,000 ly (13 kpc) from the center, the number of stars per cubic parsec drops much faster with radius.[73] Surrounding the galactic disk is a spherical Galactic Halo of stars and globular clusters that extends farther outward, but is limited in size by the orbits of two Milky Way satellites, the Large and Small Magellanic Clouds, whose closest approach to the Galactic Center is about 180,000 ly (55 kpc).[74] At this distance or beyond, the orbits of most halo objects would be disrupted by the Magellanic Clouds. Hence, such objects would probably be ejected from the vicinity of the Milky Way. The integrated absolute visual magnitude of the Milky Way is estimated to be around −20.9.[75][76][d]
+
+Both gravitational microlensing and planetary transit observations indicate that there may be at least as many planets bound to stars as there are stars in the Milky Way,[30][77] and microlensing measurements indicate that there are more rogue planets not bound to host stars than there are stars.[78][79] The Milky Way contains at least one planet per star, resulting in 100–400 billion planets, according to a January 2013 study of the five-planet star system Kepler-32 with the Kepler space observatory.[31] A different January 2013 analysis of Kepler data estimated that at least 17 billion Earth-sized exoplanets reside in the Milky Way.[80] On November 4, 2013, astronomers reported, based on Kepler space mission data, that there could be as many as 40 billion Earth-sized planets orbiting in the habitable zones of Sun-like stars and red dwarfs within the Milky Way.[81][82][83] 11 billion of these estimated planets may be orbiting Sun-like stars.[84] The nearest exoplanet may be 4.2 light-years away, orbiting the red dwarf Proxima Centauri, according to a 2016 study.[85] Such Earth-sized planets may be more numerous than gas giants.[30] Besides exoplanets, "exocomets", comets beyond the Solar System, have also been detected and may be common in the Milky Way.[86]
+
+In June 2020, astronomers from the University of Nottingham reported the possible existence of over 30 "active communicating intelligent civilizations", or Communicating Extra-Terrestrial Intelligent (CETI) civilizations (none within our current ability to detect due to various reasons including distance or size) in our own Milky Way galaxy, based on the latest astrophysical information.[87][88][89]
+
+360-degree panorama view of the Milky Way (an assembled mosaic of photographs) by ESO, the galactic centre is in the middle of the view, with galactic north up
+
+The Milky Way consists of a bar-shaped core region surrounded by a warped disk of gas, dust and stars.[93][94] The mass distribution within the Milky Way closely resembles the type Sbc in the Hubble classification, which represents spiral galaxies with relatively loosely wound arms.[1] Astronomers first began to suspect that the Milky Way is a barred spiral galaxy, rather than an ordinary spiral galaxy, in the 1960s.[95][96][97] Their suspicions were confirmed by the Spitzer Space Telescope observations in 2005[98] that showed the Milky Way's central bar to be larger than previously thought.
+
+A galactic quadrant, or quadrant of the Milky Way, refers to one of four circular sectors in the division of the Milky Way. In astronomical practice, the delineation of the galactic quadrants is based upon the galactic coordinate system, which places the Sun as the origin of the mapping system.[99]
+
+Quadrants are described using ordinals – for example, "1st galactic quadrant",[100] "second galactic quadrant",[101] or "third quadrant of the Milky Way".[102] Viewing from the north galactic pole with 0 degrees (°) as the ray that runs starting from the Sun and through the Galactic Center, the quadrants are as follows:
+
+The Sun is 25,000–28,000 ly (7.7–8.6 kpc) from the Galactic Center. This value is estimated using geometric-based methods or by measuring selected astronomical objects that serve as standard candles, with different techniques yielding various values within this approximate range.[104][14][15][105][106][107] In the inner few kpc (around 10,000 light-years radius) is a dense concentration of mostly old stars in a roughly spheroidal shape called the bulge.[108] It has been proposed that the Milky Way lacks a bulge formed due to a collision and merger between previous galaxies, and that instead it only has a pseudobulge formed by its central bar.[109] However, confusion in the literature between the (peanut shell)-shaped structure created by instabilities in the bar, versus a possible bulge with an expected half-light radius of 0.5 kpc,[110] abounds.
+
+The Galactic Center is marked by an intense radio source named Sagittarius A* (pronounced Sagittarius A-star). The motion of material around the center indicates that Sagittarius A* harbors a massive, compact object.[111] This concentration of mass is best explained as a supermassive black hole[e][104][112] (SMBH) with an estimated mass of 4.1–4.5 million times the mass of the Sun.[112] The rate of accretion of the SMBH is consistent with an inactive galactic nucleus, being estimated at around 1×10−5 M☉ per year.[113] Observations indicate that there are SMBHs located near the center of most normal galaxies.[114][115]
+
+The nature of the Milky Way's bar is actively debated, with estimates for its half-length and orientation spanning from 1 to 5 kpc (3,000–16,000 ly) and 10–50 degrees relative to the line of sight from Earth to the Galactic Center.[106][107][116] Certain authors advocate that the Milky Way features two distinct bars, one nestled within the other.[117] However, RR Lyrae variables do not trace a prominent Galactic bar.[107][118][119] The bar may be surrounded by a ring called the "5-kpc ring" that contains a large fraction of the molecular hydrogen present in the Milky Way, as well as most of the Milky Way's star formation activity. Viewed from the Andromeda Galaxy, it would be the brightest feature of the Milky Way.[120] X-ray emission from the core is aligned with the massive stars surrounding the central bar[113] and the Galactic ridge.[121]
+
+In 2010, two gigantic spherical bubbles of high energy emission were detected to the north and the south of the Milky Way core, using data from the Fermi Gamma-ray Space Telescope. The diameter of each of the bubbles is about 25,000 light-years (7.7 kpc); they stretch up to Grus and to Virgo on the night-sky of the southern hemisphere.[122][123] Subsequently, observations with the Parkes Telescope at radio frequencies identified polarized emission that is associated with the Fermi bubbles. These observations are best interpreted as a magnetized outflow driven by star formation in the central 640 ly (200 pc) of the Milky Way.[124]
+
+Later, on January 5, 2015, NASA reported observing an X-ray flare 400 times brighter than usual, a record-breaker, from Sagittarius A*. The unusual event may have been caused by the breaking apart of an asteroid falling into the black hole or by the entanglement of magnetic field lines within gas flowing into Sagittarius A*.[92]
+
+Outside the gravitational influence of the Galactic bar, the structure of the interstellar medium and stars in the disk of the Milky Way is organized into four spiral arms.[125] Spiral arms typically contain a higher density of interstellar gas and dust than the Galactic average as well as a greater concentration of star formation, as traced by H II regions[126][127] and molecular clouds.[128]
+
+The Milky Way's spiral structure is uncertain, and there is currently no consensus on the nature of the Milky Way's spiral arms.[91] Perfect logarithmic spiral patterns only crudely describe features near the Sun,[127][129] because galaxies commonly have arms that branch, merge, twist unexpectedly, and feature a degree of irregularity.[107][129][130] The possible scenario of the Sun within a spur / Local arm[127] emphasizes that point and indicates that such features are probably not unique, and exist elsewhere in the Milky Way.[129] Estimates of the pitch angle of the arms range from about 7° to 25°.[70][131] There are thought to be four spiral arms that all start near the Milky Way's center.[132] These are named as follows, with the positions of the arms shown in the image at right:
+
+Two spiral arms, the Scutum–Centaurus arm and the Carina–Sagittarius arm, have tangent points inside the Sun's orbit about the center of the Milky Way. If these arms contain an overdensity of stars compared to the average density of stars in the Galactic disk, it would be detectable by counting the stars near the tangent point. Two surveys of near-infrared light, which is sensitive primarily to red giants and not affected by dust extinction, detected the predicted overabundance in the Scutum–Centaurus arm but not in the Carina–Sagittarius arm: the Scutum–Centaurus Arm contains approximately 30% more red giants than would be expected in the absence of a spiral arm.[131][134] This observation suggests that the Milky Way possesses only two major stellar arms: the Perseus arm and the Scutum–Centaurus arm. The rest of the arms contain excess gas but not excess old stars.[91] In December 2013, astronomers found that the distribution of young stars and star-forming regions matches the four-arm spiral description of the Milky Way.[135][136][137] Thus, the Milky Way appears to have two spiral arms as traced by old stars and four spiral arms as traced by gas and young stars. The explanation for this apparent discrepancy is unclear.[137]
+
+The Near 3 kpc Arm (also called Expanding 3 kpc Arm or simply 3 kpc Arm) was discovered in the 1950s by astronomer van Woerden and collaborators through 21-centimeter radio measurements of HI (atomic hydrogen).[138][139] It was found to be expanding away from the central bulge at more than 50 km/s. It is located in the fourth galactic quadrant at a distance of about 5.2 kpc from the Sun and 3.3 kpc from the Galactic Center. The Far 3 kpc Arm was discovered in 2008 by astronomer Tom Dame (Harvard–Smithsonian CfA). It is located in the first galactic quadrant at a distance of 3 kpc (about 10,000 ly) from the Galactic Center.[139][140]
+
+A simulation published in 2011 suggested that the Milky Way may have obtained its spiral arm structure as a result of repeated collisions with the Sagittarius Dwarf Elliptical Galaxy.[141]
+
+It has been suggested that the Milky Way contains two different spiral patterns: an inner one, formed by the Sagittarius arm, that rotates fast and an outer one, formed by the Carina and Perseus arms, whose rotation velocity is slower and whose arms are tightly wound. In this scenario, suggested by numerical simulations of the dynamics of the different spiral arms, the outer pattern would form an outer pseudoring,[142] and the two patterns would be connected by the Cygnus arm.[143]
+
+Outside of the major spiral arms is the Monoceros Ring (or Outer Ring), a ring of gas and stars torn from other galaxies billions of years ago. However, several members of the scientific community recently restated their position affirming the Monoceros structure is nothing more than an over-density produced by the flared and warped thick disk of the Milky Way.[144] The structure of the Milky Way's disk is warped along an "S" curve.[145]
+
+The Galactic disk is surrounded by a spheroidal halo of old stars and globular clusters, of which 90% lie within 100,000 light-years (30 kpc) of the Galactic Center.[146] However, a few globular clusters have been found farther, such as PAL 4 and AM1 at more than 200,000 light-years from the Galactic Center. About 40% of the Milky Way's clusters are on retrograde orbits, which means they move in the opposite direction from the Milky Way rotation.[147] The globular clusters can follow rosette orbits about the Milky Way, in contrast to the elliptical orbit of a planet around a star.[148]
+
+Although the disk contains dust that obscures the view in some wavelengths, the halo component does not. Active star formation takes place in the disk (especially in the spiral arms, which represent areas of high density), but does not take place in the halo, as there is little cool gas to collapse into stars.[16] Open clusters are also located primarily in the disk.[149]
+
+Discoveries in the early 21st century have added dimension to the knowledge of the Milky Way's structure. With the discovery that the disk of the Andromeda Galaxy (M31) extends much farther than previously thought,[150] the possibility of the disk of the Milky Way extending farther is apparent, and this is supported by evidence from the discovery of the Outer Arm extension of the Cygnus Arm[133][151] and of a similar extension of the Scutum–Centaurus Arm.[152] With the discovery of the Sagittarius Dwarf Elliptical Galaxy came the discovery of a ribbon of galactic debris as the polar orbit of the dwarf and its interaction with the Milky Way tears it apart. Similarly, with the discovery of the Canis Major Dwarf Galaxy, it was found that a ring of galactic debris from its interaction with the Milky Way encircles the Galactic disk.
+
+The Sloan Digital Sky Survey of the northern sky shows a huge and diffuse structure (spread out across an area around 5,000 times the size of a full moon) within the Milky Way that does not seem to fit within current models. The collection of stars rises close to perpendicular to the plane of the spiral arms of the Milky Way. The proposed likely interpretation is that a dwarf galaxy is merging with the Milky Way. This galaxy is tentatively named the Virgo Stellar Stream and is found in the direction of Virgo about 30,000 light-years (9 kpc) away.[153]
+
+In addition to the stellar halo, the Chandra X-ray Observatory, XMM-Newton, and Suzaku have provided evidence that there is a gaseous halo with a large amount of hot gas. The halo extends for hundreds of thousand of light-years, much farther than the stellar halo and close to the distance of the Large and Small Magellanic Clouds. The mass of this hot halo is nearly equivalent to the mass of the Milky Way itself.[154][155][156] The temperature of this halo gas is between 1 and 2.5 million K (1.8 and 4.5 million °F).[157]
+
+Observations of distant galaxies indicate that the Universe had about one-sixth as much baryonic (ordinary) matter as dark matter when it was just a few billion years old. However, only about half of those baryons are accounted for in the modern Universe based on observations of nearby galaxies like the Milky Way.[158] If the finding that the mass of the halo is comparable to the mass of the Milky Way is confirmed, it could be the identity of the missing baryons around the Milky Way.[158]
+
+The Sun is near the inner rim of the Orion Arm, within the Local Fluff of the Local Bubble, and in the Gould Belt. Based upon studies of stellar orbits around Sgr A* by Gillessen and associates (2016), the Sun lies at an estimated distance of 27.14 ± 0.46 kly (8.32 ± 0.14 kpc)[15] from the Galactic Center. Boehle and associates (2016) found a smaller value of 25.64 ± 0.46 kly (7.86 ± 0.14 kpc), also using a star orbit analysis.[14] The Sun is currently 5–30 parsecs (16–98 ly) above, or north of, the central plane of the Galactic disk.[159] The distance between the local arm and the next arm out, the Perseus Arm, is about 2,000 parsecs (6,500 ly).[160] The Sun, and thus the Solar System, is located in the Milky Way's galactic habitable zone.
+
+There are about 208 stars brighter than absolute magnitude 8.5 within a sphere with a radius of 15 parsecs (49 ly) from the Sun, giving a density of one star per 69 cubic parsecs, or one star per 2,360 cubic light-years (from List of nearest bright stars). On the other hand, there are 64 known stars (of any magnitude, not counting 4 brown dwarfs) within 5 parsecs (16 ly) of the Sun, giving a density of about one star per 8.2 cubic parsecs, or one per 284 cubic light-years (from List of nearest stars). This illustrates the fact that there are far more faint stars than bright stars: in the entire sky, there are about 500 stars brighter than apparent magnitude 4 but 15.5 million stars brighter than apparent magnitude 14.[161]
+
+The apex of the Sun's way, or the solar apex, is the direction that the Sun travels through space in the Milky Way. The general direction of the Sun's Galactic motion is towards the star Vega near the constellation of Hercules, at an angle of roughly 60 sky degrees to the direction of the Galactic Center. The Sun's orbit about the Milky Way is expected to be roughly elliptical with the addition of perturbations due to the Galactic spiral arms and non-uniform mass distributions. In addition, the Sun passes through the Galactic plane approximately 2.7 times per orbit.[162] This is very similar to how a simple harmonic oscillator works with no drag force (damping) term. These oscillations were until recently thought to coincide with mass lifeform extinction periods on Earth.[163] However, a reanalysis of the effects of the Sun's transit through the spiral structure based on CO data has failed to find a correlation.[164]
+
+It takes the Solar System about 240 million years to complete one orbit of the Milky Way (a galactic year),[16] so the Sun is thought to have completed 18–20 orbits during its lifetime and 1/1250 of a revolution since the origin of humans. The orbital speed of the Solar System about the center of the Milky Way is approximately 220 km/s (490,000 mph) or 0.073% of the speed of light. The Sun moves through the heliosphere at 84,000 km/h (52,000 mph). At this speed, it takes around 1,400 years for the Solar System to travel a distance of 1 light-year, or 8 days to travel 1 AU (astronomical unit).[165] The Solar System is headed in the direction of the zodiacal constellation Scorpius, which follows the ecliptic.[166]
+
+The stars and gas in the Milky Way rotate about its center differentially, meaning that the rotation period varies with location. As is typical for spiral galaxies, the orbital speed of most stars in the Milky Way does not depend strongly on their distance from the center. Away from the central bulge or outer rim, the typical stellar orbital speed is between 210 ± 10 km/s (470,000 ± 22,000 mph).[169] Hence the orbital period of the typical star is directly proportional only to the length of the path traveled. This is unlike the situation within the Solar System, where two-body gravitational dynamics dominate, and different orbits have significantly different velocities associated with them. The rotation curve (shown in the figure) describes this rotation. Toward the center of the Milky Way the orbit speeds are too low, whereas beyond 7 kpcs the speeds are too high to match what would be expected from the universal law of gravitation.
+
+If the Milky Way contained only the mass observed in stars, gas, and other baryonic (ordinary) matter, the rotation speed would decrease with distance from the center. However, the observed curve is relatively flat, indicating that there is additional mass that cannot be detected directly with electromagnetic radiation. This inconsistency is attributed to dark matter.[34] The rotation curve of the Milky Way agrees with the universal rotation curve of spiral galaxies, the best evidence for the existence of dark matter in galaxies. Alternatively, a minority of astronomers propose that a modification of the law of gravity may explain the observed rotation curve.[170]
+
+The Milky Way began as one or several small overdensities in the mass distribution in the Universe shortly after the Big Bang.[171] Some of these overdensities were the seeds of globular clusters in which the oldest remaining stars in what is now the Milky Way formed. Nearly half the matter in the Milky Way may have come from other distant galaxies.[171] Nonetheless, these stars and clusters now comprise the stellar halo of the Milky Way. Within a few billion years of the birth of the first stars, the mass of the Milky Way was large enough so that it was spinning relatively quickly. Due to conservation of angular momentum, this led the gaseous interstellar medium to collapse from a roughly spheroidal shape to a disk. Therefore, later generations of stars formed in this spiral disk. Most younger stars, including the Sun, are observed to be in the disk.[172][173]
+
+Since the first stars began to form, the Milky Way has grown through both galaxy mergers (particularly early in the Milky Way's growth) and accretion of gas directly from the Galactic halo.[173] The Milky Way is currently accreting material from several small galaxies, including two of its largest satellite galaxies, the Large and Small Magellanic Clouds, through the Magellanic Stream. Direct accretion of gas is observed in high-velocity clouds like the Smith Cloud.[174][175] However, properties of the Milky Way such as stellar mass, angular momentum, and metallicity in its outermost regions suggest it has undergone no mergers with large galaxies in the last 10 billion years. This lack of recent major mergers is unusual among similar spiral galaxies; its neighbour the Andromeda Galaxy appears to have a more typical history shaped by more recent mergers with relatively large galaxies.[176][177]
+
+According to recent studies, the Milky Way as well as the Andromeda Galaxy lie in what in the galaxy color–magnitude diagram is known as the "green valley", a region populated by galaxies in transition from the "blue cloud" (galaxies actively forming new stars) to the "red sequence" (galaxies that lack star formation). Star-formation activity in green valley galaxies is slowing as they run out of star-forming gas in the interstellar medium. In simulated galaxies with similar properties, star formation will typically have been extinguished within about five billion years from now, even accounting for the expected, short-term increase in the rate of star formation due to the collision between both the Milky Way and the Andromeda Galaxy.[178] In fact, measurements of other galaxies similar to the Milky Way suggest it is among the reddest and brightest spiral galaxies that are still forming new stars and it is just slightly bluer than the bluest red sequence galaxies.[179]
+
+Globular clusters are among the oldest objects in the Milky Way, which thus set a lower limit on the age of the Milky Way. The ages of individual stars in the Milky Way can be estimated by measuring the abundance of long-lived radioactive elements such as thorium-232 and uranium-238, then comparing the results to estimates of their original abundance, a technique called nucleocosmochronology. These yield values of about 12.5 ± 3 billion years for CS 31082-001[181] and 13.8 ± 4 billion years for BD +17° 3248.[182] Once a white dwarf is formed, it begins to undergo radiative cooling and the surface temperature steadily drops. By measuring the temperatures of the coolest of these white dwarfs and comparing them to their expected initial temperature, an age estimate can be made. With this technique, the age of the globular cluster M4 was estimated as 12.7 ± 0.7 billion years. Age estimates of the oldest of these clusters gives a best fit estimate of 12.6 billion years, and a 95% confidence upper limit of 16 billion years.[183]
+
+In November 2018, astronomers reported the discovery of one of the oldest stars in the universe. About 13.5 billion-years-old, 2MASS J18082002-5104378 B is a tiny ultra metal-poor (UMP) star made almost entirely of materials released from the Big Bang, and is possibly one of the very first stars. The discovery of the star in the Milky Way galaxy suggests that the galaxy may be at least 3 billion years older than previously thought.[184][185][186]
+
+Several individual stars have been found in the Milky Way's halo with measured ages very close to the 13.80-billion-year age of the Universe. In 2007, a star in the galactic halo, HE 1523-0901, was estimated to be about 13.2 billion years old. As the oldest known object in the Milky Way at that time, this measurement placed a lower limit on the age of the Milky Way.[187] This estimate was made using the UV-Visual Echelle Spectrograph of the Very Large Telescope to measure the relative strengths of spectral lines caused by the presence of thorium and other elements created by the R-process. The line strengths yield abundances of different elemental isotopes, from which an estimate of the age of the star can be derived using nucleocosmochronology.[187] Another star, HD 140283, is 14.5 ± 0.7 billion years old.[35][188]
+
+According to observations utilizing adaptive optics to correct for Earth's atmospheric distortion, stars in the galaxy's bulge date to about 12.8 billion years old.[189]
+
+The age of stars in the galactic thin disk has also been estimated using nucleocosmochronology. Measurements of thin disk stars yield an estimate that the thin disk formed 8.8 ± 1.7 billion years ago. These measurements suggest there was a hiatus of almost 5 billion years between the formation of the galactic halo and the thin disk.[190] Recent analysis of the chemical signatures of thousands of stars suggests that stellar formation might have dropped by an order of magnitude at the time of disk formation, 10 to 8 billion years ago, when interstellar gas was too hot to form new stars at the same rate as before.[191]
+
+The satellite galaxies surrounding the Milky way are not randomly distributed but seemed to be the result of a break-up of some larger system producing a ring structure 500,000 light-years in diameter and 50,000 light-years wide.[192] Close encounters between galaxies, like that expected in 4 billion years with the Andromeda Galaxy rips off huge tails of gas, which, over time can coalesce to form dwarf galaxies in a ring at an arbitrary angle to the main disc.[193]
+
+The Milky Way and the Andromeda Galaxy are a binary system of giant spiral galaxies belonging to a group of 50 closely bound galaxies known as the Local Group, surrounded by a Local Void, itself being part of the Virgo Supercluster. Surrounding the Virgo Supercluster are a number of voids, devoid of many galaxies, the Microscopium Void to the "north", the Sculptor Void to the "left", the Bootes Void to the "right" and the Canes-Major Void to the South. These voids change shape over time, creating filamentous structures of galaxies. The Virgo Supercluster, for instance, is being drawn towards the Great Attractor,[194] which in turn forms part of a greater structure, called Laniakea.[195]
+
+Two smaller galaxies and a number of dwarf galaxies in the Local Group orbit the Milky Way. The largest of these is the Large Magellanic Cloud with a diameter of 14,000 light-years. It has a close companion, the Small Magellanic Cloud. The Magellanic Stream is a stream of neutral hydrogen gas extending from these two small galaxies across 100° of the sky. The stream is thought to have been dragged from the Magellanic Clouds in tidal interactions with the Milky Way.[196] Some of the dwarf galaxies orbiting the Milky Way are Canis Major Dwarf (the closest), Sagittarius Dwarf Elliptical Galaxy, Ursa Minor Dwarf, Sculptor Dwarf, Sextans Dwarf, Fornax Dwarf, and Leo I Dwarf. The smallest dwarf galaxies of the Milky Way are only 500 light-years in diameter. These include Carina Dwarf, Draco Dwarf, and Leo II Dwarf. There may still be undetected dwarf galaxies that are dynamically bound to the Milky Way, which is supported by the detection of nine new satellites of the Milky Way in a relatively small patch of the night sky in 2015.[197] There are also some dwarf galaxies that have already been absorbed by the Milky Way, such as the progenitor of Omega Centauri.[198]
+
+In 2014 researchers reported that most satellite galaxies of the Milky Way lie in a very large disk and orbit in the same direction.[199] This came as a surprise: according to standard cosmology, the satellite galaxies should form in dark matter halos, and they should be widely distributed and moving in random directions. This discrepancy is still not fully explained.[200]
+
+In January 2006, researchers reported that the heretofore unexplained warp in the disk of the Milky Way has now been mapped and found to be a ripple or vibration set up by the Large and Small Magellanic Clouds as they orbit the Milky Way, causing vibrations when they pass through its edges. Previously, these two galaxies, at around 2% of the mass of the Milky Way, were considered too small to influence the Milky Way. However, in a computer model, the movement of these two galaxies creates a dark matter wake that amplifies their influence on the larger Milky Way.[201]
+
+Current measurements suggest the Andromeda Galaxy is approaching us at 100 to 140 km/s (220,000 to 310,000 mph). In 3 to 4 billion years, there may be an Andromeda–Milky Way collision, depending on the importance of unknown lateral components to the galaxies' relative motion. If they collide, the chance of individual stars colliding with each other is extremely low, but instead the two galaxies will merge to form a single elliptical galaxy or perhaps a large disk galaxy[202] over the course of about a billion years.[203]
+
+Although special relativity states that there is no "preferred" inertial frame of reference in space with which to compare the Milky Way, the Milky Way does have a velocity with respect to cosmological frames of reference.
+
+One such frame of reference is the Hubble flow, the apparent motions of galaxy clusters due to the expansion of space. Individual galaxies, including the Milky Way, have peculiar velocities relative to the average flow. Thus, to compare the Milky Way to the Hubble flow, one must consider a volume large enough so that the expansion of the Universe dominates over local, random motions. A large enough volume means that the mean motion of galaxies within this volume is equal to the Hubble flow. Astronomers believe the Milky Way is moving at approximately 630 km/s (1,400,000 mph) with respect to this local co-moving frame of reference.[204] The Milky Way is moving in the general direction of the Great Attractor and other galaxy clusters, including the Shapley supercluster, behind it.[205] The Local Group (a cluster of gravitationally bound galaxies containing, among others, the Milky Way and the Andromeda Galaxy) is part of a supercluster called the Local Supercluster, centered near the Virgo Cluster: although they are moving away from each other at 967 km/s (2,160,000 mph) as part of the Hubble flow, this velocity is less than would be expected given the 16.8 million pc distance due to the gravitational attraction between the Local Group and the Virgo Cluster.[206]
+
+Another reference frame is provided by the cosmic microwave background (CMB). The Milky Way is moving at 552 ± 6 km/s (1,235,000 ± 13,000 mph)[18] with respect to the photons of the CMB, toward 10.5 right ascension, −24° declination (J2000 epoch, near the center of Hydra). This motion is observed by satellites such as the Cosmic Background Explorer (COBE) and the Wilkinson Microwave Anisotropy Probe (WMAP) as a dipole contribution to the CMB, as photons in equilibrium in the CMB frame get blue-shifted in the direction of the motion and red-shifted in the opposite direction.[18]
+
+In the Babylonian epic poem Enûma Eliš, the Milky Way is created from the severed tail of the primeval salt water dragoness Tiamat, set in the sky by Marduk, the Babylonian national god, after slaying her.[207][208] This story was once thought to have been based on an older Sumerian version in which Tiamat is instead slain by Enlil of Nippur,[209][210] but is now thought to be purely an invention of Babylonian propagandists with the intention to show Marduk as superior to the Sumerian deities.[210]
+
+Llys Dôn (literally "The Court of Dôn") is the traditional Welsh name for the constellation Cassiopeia. At least three of Dôn's children also have astronomical associations: Caer Gwydion ("The fortress of Gwydion") is the traditional Welsh name for the Milky Way,[211][212] and Caer Arianrhod ("The Fortress of Arianrhod") being the constellation of Corona Borealis.[citation needed]
+
+In western culture, the name "Milky Way" is derived from its appearance as a dim un-resolved "milky" glowing band arching across the night sky. The term is a translation of the Classical Latin via lactea, in turn derived from the Hellenistic Greek γαλαξίας, short for γαλαξίας κύκλος (galaxías kýklos, "milky circle"). The Ancient Greek γαλαξίας (galaxias) – from root γαλακτ-, γάλα ("milk") + -ίας (forming adjectives) – is also the root of "galaxy", the name for our, and later all such, collections of stars.[19][213][214][215]
+
+In Greek mythology, the Milky Way was formed after the trickster god Hermes suckled the infant Heracles at the breast of Hera, the queen of the gods, while she was asleep.[216][217] When Hera awoke, she tore Heracles away from her breast and splattered her breast milk across the heavens.[216][217] In another version of the story, Athena, the patron goddess of heroes, tricked Hera into suckling Heracles voluntarily,[216][217] but he bit her nipple so hard that she flung him away, spraying milk everywhere.[216][217]
+
+The Milky Way, or "milk circle", was just one of 11 "circles" the Greeks identified in the sky, others being the zodiac, the meridian, the horizon, the equator, the tropics of Cancer and Capricorn, Arctic and Antarctic circles, and two colure circles passing through both poles.[218]
+
+In Meteorologica (DK 59 A80), Aristotle (384–322 BC) wrote that the Greek philosophers Anaxagoras (c. 500–428 BC) and Democritus (460–370 BC) proposed that the Milky Way might consist of distant stars.[219] However, Aristotle himself believed the Milky Way to be caused by "the ignition of the fiery exhalation of some stars which were large, numerous and close together"[220] and that the "ignition takes place in the upper part of the atmosphere, in the region of the world which is continuous with the heavenly motions."[221][222] The Neoplatonist philosopher Olympiodorus the Younger (c. 495–570 AD) criticized this view, arguing that if the Milky Way were sublunary, it should appear different at different times and places on Earth, and that it should have parallax, which it does not. In his view, the Milky Way is celestial. This idea would be influential later in the Islamic world.[223]
+
+The Persian astronomer Abū Rayhān al-Bīrūnī (973–1048) proposed that the Milky Way is "a collection of countless fragments of the nature of nebulous stars".[224] The Andalusian astronomer Avempace (d 1138) proposed the Milky Way to be made up of many stars but appears to be a continuous image due to the effect of refraction in Earth's atmosphere, citing his observation of a conjunction of Jupiter and Mars in 1106 or 1107 as evidence.[222] Ibn Qayyim Al-Jawziyya (1292–1350) proposed that the Milky Way is "a myriad of tiny stars packed together in the sphere of the fixed stars" and that these stars are larger than planets.[225]
+
+According to Jamil Ragep, the Persian astronomer Naṣīr al-Dīn al-Ṭūsī (1201–1274) in his Tadhkira writes:
+"The Milky Way, i.e. the Galaxy, is made up of a very large number of small, tightly clustered stars, which, on account of their concentration and smallness, seem to be cloudy patches. Because of this, it was likened to milk in color."[226]
+
+Proof of the Milky Way consisting of many stars came in 1610 when Galileo Galilei used a telescope to study the Milky Way and discovered that it is composed of a huge number of faint stars.[227][228] In a treatise in 1755, Immanuel Kant, drawing on earlier work by Thomas Wright,[229] speculated (correctly) that the Milky Way might be a rotating body of a huge number of stars, held together by gravitational forces akin to the Solar System but on much larger scales.[230] The resulting disk of stars would be seen as a band on the sky from our perspective inside the disk. Wright and Kant also conjectured that some of the nebulae visible in the night sky might be separate "galaxies" themselves, similar to our own. Kant referred to both the Milky Way and the "extragalactic nebulae" as "island universes", a term still current up to the 1930s.[231][232][233]
+
+The first attempt to describe the shape of the Milky Way and the position of the Sun within it was carried out by William Herschel in 1785 by carefully counting the number of stars in different regions of the visible sky. He produced a diagram of the shape of the Milky Way with the Solar System close to the center.[234]
+
+In 1845, Lord Rosse constructed a new telescope and was able to distinguish between elliptical and spiral-shaped nebulae. He also managed to make out individual point sources in some of these nebulae, lending credence to Kant's earlier conjecture.[235][236]
+
+In 1904, studying the proper motions of stars, Jacobus Kapteyn reported that these were not random, as it was believed in that time; stars could be divided into two streams, moving in nearly opposite directions.[237]  It was later realized that Kapteyn's data had been the first evidence of the rotation of our Galaxy,[238] which ultimately led to the finding of galactic rotation by Bertil Lindblad and Jan Oort.
+
+In 1917, Heber Curtis had observed the nova S Andromedae within the Great Andromeda Nebula (Messier object 31). Searching the photographic record, he found 11 more novae. Curtis noticed that these novae were, on average, 10 magnitudes fainter than those that occurred within the Milky Way. As a result, he was able to come up with a distance estimate of 150,000 parsecs. He became a proponent of the "island universes" hypothesis, which held that the spiral nebulae were independent galaxies.[239][240] In 1920 the Great Debate took place between Harlow Shapley and Heber Curtis, concerning the nature of the Milky Way, spiral nebulae, and the dimensions of the Universe. To support his claim that the Great Andromeda Nebula is an external galaxy, Curtis noted the appearance of dark lanes resembling the dust clouds in the Milky Way, as well as the significant Doppler shift.[241]
+
+The controversy was conclusively settled by Edwin Hubble in the early 1920s using the Mount Wilson observatory 2.5 m (100 in) Hooker telescope. With the light-gathering power of this new telescope, he was able to produce astronomical photographs that resolved the outer parts of some spiral nebulae as collections of individual stars. He was also able to identify some Cepheid variables that he could use as a benchmark to estimate the distance to the nebulae. He found that the Andromeda Nebula is 275,000 parsecs from the Sun, far too distant to be part of the Milky Way.[242][243]
+
+The ESA spacecraft Gaia provides distance estimates by determining the parallax of a billion stars and is mapping the Milky Way with four planned releases of maps in 2016, 2018, 2021 and 2024.[244][245] A study in 2020 concluded that Gaia detected a wobbling motion of the galaxy, which might be caused by "torques from a misalignment of the disc's rotation axis with respect to the principle axis of a non-spherical halo, or from accreted matter in the halo acquired during late infall, or from nearby, interacting satellite galaxies and their consequent tides".[246]

en/6027.html.txt

@@ -0,0 +1,128 @@
+A sailing ship is a sea-going vessel that uses sails mounted on masts to harness the power of wind and propel the vessel. There is a variety of sail plans that propel sailing ships, employing square-rigged or fore-and-aft sails. Some ships carry square sails on each mast—the brig and full-rigged ship, said to be "ship-rigged" when there are three or more masts.[1] Others carry only fore-and-aft sails on each mast—schooners. Still others employ a combination of square and fore-and aft sails, including the barque, barquentine, and brigantine.[2]  Sailing ships developed differently in Asia, which produced the junk and dhow—vessels that incorporated innovations absent in European ships of the time. Technically in the Age of Sail a ship was a specific type of vessel, with a bowsprit and three masts, each of which consists of a lower, top, and topgallant mast.[3]
+
+Sailing ships with predominantly square rigs became prevalent during the Age of Discovery, when they crossed oceans between continents and around the world. Most sailing ships were merchantmen, but the Age of Sail also saw the development of large fleets of well-armed warships. The Age of Sail waned with the advent of steam-powered ships, which did not depend upon a favourable wind.
+
+The first sailing vessels were developed for use in the South China Sea and also independently in lands abutting the western Mediterranean Sea by the 2nd millennium BCE. In Asia, early vessels were equipped with crab claw sails—with a spar on the top and bottom of the sail, arranged fore-and-aft when needed. In the Mediterranean, vessels were powered downwind by square sails that supplemented propulsion by oars. Sailing ships evolved differently in the South China Sea and in the Indian Ocean, where fore-and-aft sail plans were developed several centuries into the Common Era. By the time of the Age of Discovery—starting in the 15th century—square-rigged, multi-masted vessels were the norm and were guided by navigation techniques that included the magnetic compass and making sightings of the sun and stars that allowed transoceanic voyages. The Age of Sail reached its peak in the 18th and 19th centuries with large, heavily armed battleships and merchant sailing ships that were able to travel at speeds that exceeded those of the newly introduced steamships. Ultimately, the steamships' independence from the wind and their ability to take shorter routes, passing through the Suez and Panama Canals,[4] made sailing ships uneconomical.
+
+Initially sails provided supplementary power to ships with oars, because the sails were not designed to sail to windward. In Asia sailing ships were equipped with fore-and-aft rigs that made sailing to windward possible. Later square-rigged vessels too were able to sail to windward, and became the standard for European ships through the Age of Discovery when vessels ventured around Africa to India, to the Americas and around the world. Later during this period—in the late 15th century—"ship-rigged" vessels with multiple square sails on each mast appeared and became common for sailing ships.[5]
+
+Sailing ships in the Mediterranean region date to 3000 BCE, when Egyptians used a bipod mast to support a single square sail on a vessel that mainly relied on multiple paddlers. Later the mast became a single pole, and paddles were supplanted with oars. Such vessels plied both the Nile and the Mediterranean coast. The inhabitants of Crete had sailing vessels by 1200 BCE. Between 1000 BCE and 400 CE, the Phoenicians, Greeks and Romans developed ships that were powered by square sails, sometimes with oars to supplement their capabilities. Such vessels used a steering oar as a rudder to control direction. Fore-and-aft sails started appearing on sailing vessels in the Mediterranean ca.1200 CE,[5] an influence of rigs introduced in Asia and the Indian Ocean.[6]
+
+Starting in the 8th century in Denmark, Vikings were building clinker-constructed longships propelled by a single, square sail, when practical, and oars, when necessary.[7] A related craft was the knarr, which plied the Baltic and North Seas, using primarily sail power.[8] The windward edge of the sail was stiffened with a beitass, a pole that fitted into the lower corner of the sail, when sailing close to the wind.[9]
+
+The first sea-going sailing ships in Asia were developed by the Austronesian peoples from what is now Southern China and Taiwan. Their invention of catamarans, outriggers, and crab claw sails enabled the Austronesian Expansion at around 3000 to 1500 BCE. From Taiwan, they rapidly colonized the islands of Maritime Southeast Asia, then sailed further onwards to Micronesia, Island Melanesia, Polynesia, and Madagascar. Austronesian rigs were distinctive in that they had spars supporting both the upper and lower edges of the sails (and sometimes in between), in contrast to western rigs which only had a spar on the upper edge.[10][11][12]
+
+Early Austronesian sailors also influenced the development of sailing technologies in Sri Lanka and Southern India through the Austronesian maritime trade network of the Indian Ocean, the precursor to the spice trade route and the maritime silk road.[13]
+Austronesians established the first maritime trade network with ocean-going merchant ships which plied the early trade routes from Southeast Asia from at least 1500 BCE. They reached as far northeast as Japan and as far west as eastern Africa. They colonized Madagascar and their trade routes were the precursors to the spice trade route and the maritime silk road. They mainly facilitated trade of goods from China and Japan to South India, Sri Lanka, the Persian Gulf, and the Red Sea.[13]][14][15] An important invention in this region was the fore-and-aft rig, which made sailing against the wind possible. Such sails may have originated at least several hundred years BCE.[16] Balance lugsails and tanja sails also originated from this region. Vessels with such sails explored and traded along the western coast of Africa. This type of sail propagated to the west and influenced Arab lateen designs.[16]
+
+Large Austronesian trading ships with as many as four sails were recorded by Han Dynasty (206 BCE – 220 CE) scholars as the kunlun bo (崑崙舶, lit. "ship of the Kunlun people"). They were booked by Chinese Buddhist pilgrims for passage to Southern India and Sri Lanka.[17] Bas reliefs of Sailendran and Srivijayan large merchant ships with various configurations of tanja sails and outriggers are also found in the Borobudur temple, dating back to the 8th century CE.[18][19]
+
+By the 10th century CE, the Song Dynasty started building the first Chinese junks, which were adopted from the design of the Javanese djongs. The junk rig in particular, became associated with Chinese coast-hugging trading ships.[20][21] Junks in China were constructed from teak with pegs and nails; they featured watertight compartments and acquired center-mounted tillers and rudders.[22] These ships became the basis for the development of Chinese warships during the Mongol Yuan Dynasty, and were used in the unsuccessful Mongol invasions of Japan and Java.[23][24]
+
+The Ming dynasty (1368–1644) saw the use of junks as long-distance trading vessels. Chinese Admiral Zheng He reportedly sailed to India, Arabia, and southern Africa on a trade and diplomatic mission.[25][26] Literary lore suggests that his largest vessel, the "Treasure Ship", measured 400 feet (120 m) in length and 150 feet (46 m) in width, whereas modern research suggests that it was unlikely to have exceeded 200 feet (61 m) in length.[27]
+
+The Indian Ocean was the venue for increasing trade between India and Africa between 1200 and 1500. The vessels employed would be classified as dhows with lateen rigs. During this interval such vessels grew in capacity from 100 to 400 tonnes. Dhows were often built with teak planks from India and Southeast Asia, sewn together with coconut husk fiber—no nails were employed. This period also saw the implementation of center-mounted rudders, controlled with a tiller.[28]
+
+Technological advancements that were important to the Age of Discovery in the 15th century were the adoption of the magnetic compass and advances in ship design.
+
+The compass was an addition to the ancient method of navigation based on sightings of the sun and stars. The compass was invented by Chinese. It had been used for navigation in China by the 11th century and was adopted by the Arab traders in the Indian Ocean. The compass spread to Europe by the late 12th or early 13th century.[6] Use of the compass for navigation in the Indian Ocean was first mentioned in 1232.[20] The Europeans used a "dry" compass, with a needle on a pivot. The compass card was also a European invention.[20]
+
+At the beginning of the 15th century, the carrack was the most capable European ocean-going ship. It was carvel-built and large enough to be stable in heavy seas. It was capable of carrying a large cargo and the provisions needed for very long voyages.  Later carracks were square-rigged on the foremast and mainmast and lateen-rigged on the mizzenmast. They had a high rounded stern with large aftcastle, forecastle and bowsprit at the stem.  As the predecessor of the galleon, the carrack was one of the most influential ship designs in history; while ships became more specialized in the following centuries, the basic design remained unchanged throughout this period.[29]
+
+Ships of this era were only able to sail approximately 70° into the wind and tacked from one side to the other across the wind with difficulty, which made it challenging to avoid shipwrecks when near shores or shoals during storms.[30] Nonetheless, such vessels reached India around Africa with Vasco da Gama,[31] the Americas with Christopher Columbus,[32] and around the world under Ferdinand Magellan.[33]
+
+Sailing ships became longer and faster over time, with ship-rigged vessels carrying taller masts with more square sails. Other sail plans emerged, as well, that had just fore-and-aft sails (schooners), or a mixture of the two (brigantines, barques and barquentines).[5]
+
+Cannon were present in the 14th century, but did not become common at sea until they could be reloaded quickly enough to be reused in the same battle. The size of a ship required to carry a large number of cannon made oar-based propulsion impossible, and warships came to rely primarily on sails. The sailing man-of-war emerged during the 16th century.[34]
+
+By the middle of the 17th century, warships were carrying increasing numbers of cannon on three decks. Naval tactics evolved to bring each ship's firepower to bear in a line of battle—coordinated movements of a fleet of warships to engage a line of ships in the enemy fleet.[35] Carracks with a single cannon deck evolved into galleons with as many as two full cannon decks,[36] which evolved into the man-of-war, and further into the ship of the line—designed for engaging the enemy in a line of battle. One side of a ship was expected to shoot broadsides against an enemy ship at close range.[35] In the 18th century, the small and fast frigate and sloop-of-war—too small to stand in the line of battle—evolved to convoy trade, scout for enemy ships and blockade enemy coasts.[37]
+
+Fast schooners and brigantines, called Baltimore clippers, were used for blockade running and as privateers in the early 1800s. These evolved into three-masted, usually ship-rigged sailing vessels, optimized for speed with fine lines that lessened their cargo capacity.[38] Sea trade with China became important in that period which favored a combination of speed and cargo volume, which was met by building vessels with long waterlines, fine bows and tall masts, generously equipped with sails for maximum speed. Masts were as high as 100 feet (30 m) and were able to achieve speeds of 19 knots (35 km/h), allowing for passages of up to 465 nautical miles (861 km) per 24 hours. Clippers yielded to bulkier, slower vessels, which became economically competitive in the mid 19th century.[39]
+
+During the Age of Sail, ships' hulls were under frequent attack by shipworm (which affected the structural strength of timbers), and barnacles and various marine weeds (which affected ship speed).[40] Since before the common era, a variety of coatings had been applied to hulls to counter this effect, including pitch, wax, tar, oil, sulfur and arsenic.[41] In the mid 18th century copper sheathing was developed as a defense against such bottom fouling.[42] After coping with problems of galvanic deterioration of metal hull fasteners, sacrificial anodes were developed, which were designed to corrode, instead of the hull fasteners.[43] The practice became widespread on naval vessels, starting in the late18th century,[44] and on merchant vessels, starting in the early 19th century, until the advent of iron and steel hulls.[43]
+
+Iron-hulled sailing ships, often referred to as "windjammers" or "tall ships",[45] represented the final evolution of sailing ships at the end of the Age of Sail. They were built to carry bulk cargo for long distances in the nineteenth and early twentieth centuries. They were the largest of merchant sailing ships, with three to five masts and square sails, as well as other sail plans. They carried lumber, guano, grain or ore between continents. Later examples had steel hulls.  Iron-hulled sailing ships were mainly built from the 1870s to 1900, when steamships began to outpace them economically, due to their ability to keep a schedule regardless of the wind.  Steel hulls also replaced iron hulls at around the same time. Even into the twentieth century, sailing ships could hold their own on transoceanic voyages such as Australia to Europe, since they did not require bunkerage for coal nor fresh water for steam, and they were faster than the early steamers, which usually could barely make 8 knots (15 km/h).[46]
+
+The four-masted, iron-hulled ship, introduced in 1875 with the full-rigged County of Peebles, represented an especially efficient configuration that prolonged the competitiveness of sail against steam in the later part of the 19th century.[47] The largest example of such ships was the five-masted, full-rigged ship Preussen, which had a load capacity of 7,800 tonnes.[48]  Ships transitioned from all sail to all steam-power during from the mid 19th century into the 20th.[49] Five-masted Preussen used steam power for driving the winches, hoists and pumps, and could be manned by a crew of 48, compared with four-masted Kruzenshtern, which has a crew of 257.[50]
+
+Coastal top-sail schooners with a crew as small as two managing the sail handling became an efficient way to carry bulk cargo, since only the fore-sails required tending while tacking and steam-driven machinery was often available for raising the sails and the anchor.[51]
+
+In the 20th century, the DynaRig allowed central, automated control of all sails in a manner that obviates the need for sending crew aloft. This was developed in the 1960s in Germany as a low-carbon footprint propulsion alternative for commercial ships. The rig automatically sets and reefs sails; its mast rotates to align the sails with the wind. The sailing yachts Maltese Falcon and Black Pearl employ the rig.[50][52]
+
+Every sailing ship has a sail plan that is adapted to the purpose of the vessel and the ability of the crew; each has a hull, rigging and masts to hold up the sails that use the wind to power the ship; the masts are supported by standing rigging and the sails are adjusted by running rigging.
+
+Hull shapes for sailing ships evolved from being relatively short and blunt to being longer and finer at the bow.[5] By the nineteenth century, ships were built with reference to a half model, made from wooden layers that were pinned together. Each layer could be scaled to the actual size of the vessel in order to lay out its hull structure, starting with the keel and leading to the ship's ribs. The ribs were pieced together from curved elements, called futtocks and tied in place until the installation of the planking. Typically, planking was caulked with a tar-impregnated yarn made from manila or hemp to make the planking watertight.[53] Starting in the mid-19th century, iron was used first for the hull structure and later for its watertight sheathing.[54]
+
+Until the mid-19th century all vessels' masts were made of wood formed from a single or several pieces of timber which typically consisted of the trunk of a conifer tree. From the 16th century, vessels were often built of a size requiring masts taller and thicker than could be made from single tree trunks. On these larger vessels, to achieve the required height, the masts were built from up to four sections (also called masts), known in order of rising height above the decks as the lower, top, topgallant and royal masts.[56] Giving the lower sections sufficient thickness necessitated building them up from separate pieces of wood. Such a section was known as a made mast, as opposed to sections formed from single pieces of timber, which were known as pole masts.[57]  Starting in the second half of the 19th century, masts were made of iron or steel.[5]
+
+For ships with square sails the principal masts, given their standard names in bow to stern (front to back) order, are:
+
+Each rig is configured in a sail plan, appropriate to the size of the sailing craft. Both square-rigged and fore-and-aft rigged vessels have been built with a wide range of configurations for single and multiple masts.[60]
+
+Types of sail that can be part of a sail plan can be broadly classed by how they are attached to the sailing craft:
+
+Sailing ships have standing rigging to support the masts and running rigging to raise the sails and control their ability to draw power from the wind. The running rigging has three main roles, to support the sail structure, to shape the sail and to adjust its angle to the wind. Square-rigged vessels require more controlling lines than fore-and-aft rigged ones.
+
+Sailing ships prior to the mid-19th century used wood masts with hemp-fiber standing rigging. As rigs became taller by the end of the 19th Century, masts relied more heavily on successive spars, stepped one atop the other to form the whole, from bottom to top: the lower mast, top mast, and topgallant mast. This construction relied heavily on support by a complex array of stays and shrouds. Each stay in either the fore-and-aft or athwartships direction had a corresponding one in the opposite direction providing counter-tension. Fore-and-aft the system of tensioning started with the stays that were anchored in front each mast. Shrouds were tensioned by pairs deadeyes, circular blocks that had the large-diameter line run around them, whilst multiple holes allowed smaller line—lanyard—to pass multiple times between the two and thereby allow tensioning of the shroud. After the mid-19th century square-rigged vessels were equipped with steel-cable standing rigging.[61]
+
+Halyards, used to raise and lower the yards, are the primary supporting lines.[62] In addition, square rigs have lines that lift the sail or the yard from which it is suspended that include: brails, buntlines, lifts and leechlines. Bowlines and clew lines shape a square sail.[55] To adjust the angle of the sail to wind braces are used to adjust the fore and aft angle of a yard of a square sail, while sheets attach to the clews (bottom corners) of a sail to control the sail's angle to the wind. Sheets run aft, whereas tacks are used to haul the clew of a square sail forward.[55]
+
+The crew of a sailing ship is divided between officers (the captain and his subordinates) and seamen or ordinary hands. An able seaman was expected to "hand, reef, and steer" (handle the lines and other equipment, reef the sails, and steer the vessel).[63]  The crew is organized to stand watch—the oversight of the ship for a period—typically four hours each.[64] Richard Henry Dana Jr. and Herman Melville each had personal experience aboard sailing vessels of the 19th century.
+
+Dana described the crew of the merchant brig, Pilgrim, as comprising six to eight common sailors,  four specialist crew members (the steward, cook, carpenter and sailmaker), and three officers: the captain, the first mate and the second mate. He contrasted the American crew complement with that of other nations on whose similarly sized ships the crew might number as many as 30.[65] Larger merchant vessels had larger crews.[66]
+
+Melville described the crew complement of the frigate warship, United States, as about 500—including officers, enlisted personnel and 50 Marines. The crew was divided into the starboard and larboard watches. It was also divided into three tops, bands of crew responsible for setting sails on the three masts; a band of sheet-anchor men, whose station was forward and whose job was to tend the fore-yard, anchors and forward sails; the after guard, who were stationed aft and tended the mainsail, spanker and man the various sheets, controlling the position of the sails; the waisters, who were stationed midships and had menial duties attending the livestock, etc.; and the holders, who occupied the lower decks of the vessel and were responsible for the inner workings of the ship. He additionally named such positions as, boatswains, gunners, carpenters, coopers, painters, tinkers, stewards, cooks and various boys as functions on the man-of-war.[67] 18-19th century ships of the line had a complement as high as 850.[68]
+
+Handling a sailing ship requires management of its sails to power—but not overpower—the ship and navigation to guide the ship, both at sea and in and out of harbors.
+
+Key elements of sailing a ship are setting the right amount of sail to generate maximum power without endangering the ship, adjusting the sails to the wind direction on the course sailed, and changing tack to bring the wind from one side of the vessel to the other.
+
+A sailing ship crew manages the running rigging of each square sail. Each sail has two sheets that control its lower corners, two braces that control the angle of the yard, two clewlines, four buntlines and two reef tackles. All these lines must be manned as the sail is deployed and the yard raised. They use a halyard to raise each yard and its sail; then they pull or ease the braces to set the angle of the yard across the vessel; they pull on sheets to haul lower corners of the sail, clews, out to yard below. Under way, the crew manages reef tackles, haul leeches, reef points, to manage the size and angle of the sail; bowlines pull the leading edge of the sail (leech) taut when close hauled. When furling the sail, the crew uses clewlines, haul up the clews and buntlines to haul up the middle of sail up; when lowered, lifts  support each yard.[69]
+
+In strong winds, the crew is directed to reduce the number of sails or, alternatively, the amount of each given sail that is presented to the wind by a process called reefing. To pull the sail up, seamen on the yardarm pull on reef tackles, attached to reef cringles, to pull the sail up and secure it with lines, called reef points.[70] Dana spoke of the hardships of sail handling during high wind and rain or with ice covering the ship and its rigging.[65]
+
+Sailing vessels cannot sail directly into the wind. Instead, square-riggers must sail a course that is between 60° and 70° away from the wind direction[71] and fore-and aft vessels can typically sail no closer than 45°.[72] To reach a destination, sailing vessels may have to change course and allow the wind to come from the opposite side in a procedure, called tacking, when the wind comes across the bow during the maneuver.
+
+When tacking, a square-rigged vessel's sails must be presented squarely to the wind and thus impede forward motion as they are swung around via the yardarms through the wind as controlled by the vessel's running rigging, using braces—adjusting the fore and aft angle of each yardarm around the mast—and sheets attached to the clews (bottom corners) of each sail to control the sail's angle to the wind.[55] The procedure is to turn the vessel into the wind with the hind-most fore-and-aft sail (the spanker), pulled to windward to help turn the ship through the eye of the wind. Once the ship has come about, all the sails are adjusted to align properly with the new tack. Because square-rigger masts are more strongly braced from behind than from ahead, tacking is a dangerous procedure in strong winds; the ship may lose forward momentum (become caught in stays) and the rigging may fail from the wind coming from ahead. The ship may also lose momentum at wind speeds of less than 10 knots (19 km/h).[71] Under these conditions, the choice may be to wear ship—to turn the ship away from the wind and around 240° onto the next tack (60° off the wind).[73][74]
+
+A fore-and-aft rig permits the wind to flow past the sail, as the craft head through the eye of the wind. Most rigs pivot around a stay or the mast, while this occurs. For a jib, the old leeward sheet is released as the craft heads through the wind and the old windward sheet is tightened as the new leeward sheet to allow the sail to draw wind. Mainsails are often self-tending and slide on a traveler to the opposite side.[75] On certain rigs, such as lateens[76] and luggers,[77] the sail may be partially lowered to bring it to the opposite side.
+
+Early navigational techniques employed observations of the sun, stars, waves and birdlife. In the 15th century, the Chinese were using the magnetic compass to identify direction of travel. By the 16th century in Europe, navigational instruments included the quadrant, the astrolabe, cross staff, dividers and compass. By the time of the Age of Exploration these tools were being used in combination with a log to measure speed, a lead line to measure soundings, and a lookout to identify potential hazards. Later, an accurate marine sextant became standard for determining latitude and an accurate chronometer became standard for determining longitude.[78][79]
+
+Passage planning begins with laying out a route along a chart, which comprises a series of courses between fixes—verifiable locations that confirm the actual track of the ship on the ocean. Once a course has been set, the person at the helm attempts to follow its direction with reference to the compass. The navigator notes the time and speed at each fix to estimate the arrival at the next fix, a process called dead reckoning. For coast-wise navigation, sightings from known landmarks or navigational aids may be used to establish fixes, a process called pilotage.[1] At sea, sailing ships used celestial navigation on a daily schedule, as follows:[80]
+
+Fixes were taken with a marine sextant, which measures the distance of the celestial body above the horizon.[78]
+
+Given the limited maneuverability of sailing ships, it could be difficult to enter and leave harbor with the presence of a tide without coordinating arrivals with a flooding tide and departures with an ebbing tide. In harbor, a sailing ship stood at anchor, unless it needed to be loaded or unloaded at a dock or pier, in which case it had to be towed to shore by its boats or by other vessels.[81]
+
+These are examples of sailing ships; some terms have multiple meanings:
+
+Defined by general configuration
+
+
+
+Defined by sail plan
+
+All masts have fore-and-aft sails
+
+All masts have square sails
+
+Mixture of masts with square sails and masts with fore-and-aft sails
+
+Military vessels
+
+
+
+Götheborg, a sailing replica of a Swedish East Indiaman
+
+Cutty Sark, the only surviving clipper ship[82]
+
+USS Constitution with sails on display in 2012, the oldest commissioned warship still afloat[83]
+
+French steam-powered, screw-propelled battleship, Napoléon
+
+INS Tarangini, a three-masted barque in service with the Indian Navy
+
+Maltese Falcon with all-rotating, stayless DynaRig
+
+Media related to Sailing ships at Wikimedia Commons

en/6028.html.txt

@@ -0,0 +1,122 @@
+
+
+A car (or automobile) is a wheeled motor vehicle used for transportation.  Most definitions of cars say that they run primarily on roads, seat one to eight people, have four tires, and mainly transport people rather than goods.[2][3]
+
+Cars came into global use during the 20th century, and developed economies depend on them. The year 1886 is regarded as the birth year of the modern car when German inventor Karl Benz patented his Benz Patent-Motorwagen. Cars became widely available in the early 20th century. One of the first cars accessible to the masses was the 1908 Model T, an American car manufactured by the Ford Motor Company. Cars were rapidly adopted in the US, where they replaced animal-drawn carriages and carts, but took much longer to be accepted in Western Europe and other parts of the world.[citation needed]
+
+Cars have controls for driving, parking, passenger comfort, and a variety of lights. Over the decades, additional features and controls have been added to vehicles, making them progressively more complex, but also more reliable and easier to operate.[citation needed] These include rear-reversing cameras, air conditioning, navigation systems, and in-car entertainment. Most cars in use in the 2010s are propelled by an internal combustion engine, fueled by the combustion of fossil fuels. Electric cars, which were invented early in the history of the car, became commercially available in the 2000s and are predicted to cost less to buy than gasoline cars before 2025.[4][5] The transition from fossil fuels to electric cars features prominently in most climate change mitigation scenarios.[6]
+
+There are costs and benefits to car use. The costs to the individual include acquiring the vehicle, interest payments (if the car is financed), repairs and maintenance, fuel, depreciation, driving time, parking fees, taxes, and insurance.[7] The costs to society include maintaining roads, land use, road congestion, air pollution, public health, healthcare, and disposing of the vehicle at the end of its life. Traffic collisions are the largest cause of injury-related deaths worldwide.[8]
+
+The personal benefits include on-demand transportation, mobility, independence, and convenience.[9] The societal benefits include economic benefits, such as job and wealth creation from the automotive industry, transportation provision, societal well-being from leisure and travel opportunities, and revenue generation from the taxes. People's ability to move flexibly from place to place has far-reaching implications for the nature of societies.[10] There are around 1 billion cars in use worldwide. The numbers are increasing rapidly, especially in China, India and other newly industrialized countries.[11]
+
+The English word car is believed to originate from Latin carrus/carrum "wheeled vehicle" or (via Old North French) Middle English carre "two-wheeled cart," both of which in turn derive from Gaulish karros "chariot."[12][13] It originally referred to any wheeled horse-drawn vehicle, such as a cart, carriage, or wagon.[14][15]
+
+"Motor car," attested from 1895, is the usual formal term in British English.[3] "Autocar," a variant likewise attested from 1895 and literally meaning "self-propelled car," is now considered archaic.[16] "Horseless carriage" is attested from 1895.[17]
+
+"Automobile," a classical compound derived from Ancient Greek autós (αὐτός) "self" and Latin mobilis "movable," entered English from French and was first adopted by the Automobile Club of Great Britain in 1897.[18] It fell out of favour in Britain and is now used chiefly in North America,[19] where the abbreviated form "auto" commonly appears as an adjective in compound formations like "auto industry" and "auto mechanic".[20][21] Both forms are still used in everyday Dutch (auto/automobiel) and German (Auto/Automobil).[citation needed]
+
+The first working steam-powered vehicle was designed — and quite possibly built — by Ferdinand Verbiest, a Flemish member of a Jesuit mission in China around 1672. It was a 65-cm-long scale-model toy for the Chinese Emperor that was unable to carry a driver or a passenger.[9][22][23] It is not known with certainty if Verbiest's model was successfully built or run.[23]
+
+Nicolas-Joseph Cugnot is widely credited with building the first full-scale, self-propelled mechanical vehicle or car in about 1769; he created a steam-powered tricycle.[24]  He also constructed two steam tractors for the French Army, one of which is preserved in the French National Conservatory of Arts and Crafts.[25] His inventions were, however, handicapped by problems with water supply and maintaining steam pressure.[25] In 1801, Richard Trevithick built and demonstrated his Puffing Devil road locomotive, believed by many to be the first demonstration of a steam-powered road vehicle. It was unable to maintain sufficient steam pressure for long periods and was of little practical use.
+
+The development of external combustion engines is detailed as part of the history of the car but often treated separately from the development of true cars.  A variety of steam-powered road vehicles were used during the first part of the 19th century, including steam cars, steam buses, phaetons, and steam rollers.  Sentiment against them led to the Locomotive Acts of 1865.
+
+In 1807, Nicéphore Niépce and his brother Claude created what was probably the world's first internal combustion engine (which they called a Pyréolophore), but they chose to install it in a boat on the river Saone in France.[26] Coincidentally, in 1807 the Swiss inventor François Isaac de Rivaz designed his own 'de Rivaz internal combustion engine' and used it to develop the world's first vehicle to be powered by such an engine. The Niépces' Pyréolophore was fuelled by a mixture of Lycopodium powder (dried spores of the Lycopodium plant), finely crushed coal dust and resin that were mixed with oil, whereas de Rivaz used a mixture of hydrogen and oxygen.[26] Neither design was very successful, as was the case with others, such as Samuel Brown, Samuel Morey, and Etienne Lenoir with his hippomobile, who each produced vehicles (usually adapted carriages or carts) powered by internal combustion engines.[1]
+
+In November 1881, French inventor Gustave Trouvé demonstrated the first working (three-wheeled) car powered by electricity at the International Exposition of Electricity, Paris.[27] Although several other German engineers (including Gottlieb Daimler, Wilhelm Maybach, and Siegfried Marcus) were working on the problem at about the same time, Karl Benz generally is acknowledged as the inventor of the modern car.[1]
+
+In 1879, Benz was granted a patent for his first engine, which had been designed in 1878. Many of his other inventions made the use of the internal combustion engine feasible for powering a vehicle. His first Motorwagen was built in 1885 in Mannheim, Germany. He was awarded the patent for its invention as of his application on 29 January 1886 (under the auspices of his major company, Benz & Cie., which was founded in 1883). Benz began promotion of the vehicle on 3 July 1886, and about 25 Benz vehicles were sold between 1888 and 1893, when his first four-wheeler was introduced along with a cheaper model. They also were powered with four-stroke engines of his own design. Emile Roger of France, already producing Benz engines under license, now added the Benz car to his line of products. Because France was more open to the early cars, initially more were built and sold in France through Roger than Benz sold in Germany. In August 1888 Bertha Benz, the wife of Karl Benz, undertook the first road trip by car, to prove the road-worthiness of her husband's invention.
+
+In 1896, Benz designed and patented the first internal-combustion flat engine, called boxermotor. During the last years of the nineteenth century, Benz was the largest car company in the world with 572 units produced in 1899 and, because of its size, Benz & Cie., became a joint-stock company. The first motor car in central Europe and one of the first factory-made cars in the world, was produced by Czech company Nesselsdorfer Wagenbau (later renamed to Tatra) in 1897, the Präsident automobil.
+
+Daimler and Maybach founded Daimler Motoren Gesellschaft (DMG) in Cannstatt in 1890, and sold their first car in 1892 under the brand name Daimler. It was a horse-drawn stagecoach built by another manufacturer, which they retrofitted with an engine of their design. By 1895 about 30 vehicles had been built by Daimler and Maybach, either at the Daimler works or in the Hotel Hermann, where they set up shop after disputes with their backers. Benz, Maybach and the Daimler team seem to have been unaware of each other's early work. They never worked together; by the time of the merger of the two companies, Daimler and Maybach were no longer part of DMG. Daimler died in 1900 and later that year, Maybach designed an engine named Daimler-Mercedes that was placed in a specially ordered model built to specifications set by Emil Jellinek. This was a production of a small number of vehicles for Jellinek to race and market in his country. Two years later, in 1902, a new model DMG car was produced and the model was named Mercedes after the Maybach engine, which generated 35 hp. Maybach quit DMG shortly thereafter and opened a business of his own. Rights to the Daimler brand name were sold to other manufacturers.
+
+Karl Benz proposed co-operation between DMG and Benz & Cie. when economic conditions began to deteriorate in Germany following the First World War, but the directors of DMG refused to consider it initially. Negotiations between the two companies resumed several years later when these conditions worsened and, in 1924 they signed an Agreement of Mutual Interest, valid until the year 2000. Both enterprises standardized design, production, purchasing, and sales and they advertised or marketed their car models jointly, although keeping their respective brands. On 28 June 1926, Benz & Cie. and DMG finally merged as the Daimler-Benz company, baptizing all of its cars Mercedes Benz, as a brand honoring the most important model of the DMG cars, the Maybach design later referred to as the 1902 Mercedes-35 hp, along with the Benz name. Karl Benz remained a member of the board of directors of Daimler-Benz until his death in 1929, and at times, his two sons also participated in the management of the company.
+
+In 1890, Émile Levassor and Armand Peugeot of France began producing vehicles with Daimler engines, and so laid the foundation of the automotive industry in France. In 1891, Auguste Doriot and his Peugeot colleague Louis Rigoulot completed the longest trip by a gasoline-powered vehicle when their self-designed and built Daimler powered Peugeot Type 3 completed 2,100 km (1,300 miles) from Valentigney to Paris and Brest and back again. They were attached to the first Paris–Brest–Paris bicycle race, but finished 6 days after the winning cyclist, Charles Terront.
+
+The first design for an American car with a gasoline internal combustion engine was made in 1877 by George Selden of Rochester, New York. Selden applied for a patent for a car in 1879, but the patent application expired because the vehicle was never built. After a delay of sixteen years and a series of attachments to his application, on 5 November 1895, Selden was granted a United States patent (U.S. Patent 549,160) for a two-stroke car engine, which hindered, more than encouraged, development of cars in the United States. His patent was challenged by Henry Ford and others, and overturned in 1911.
+
+In 1893, the first running, gasoline-powered American car was built and road-tested by the Duryea brothers of Springfield, Massachusetts. The first public run of the Duryea Motor Wagon took place on 21 September 1893, on Taylor Street in Metro Center Springfield.[28][29] The Studebaker Automobile Company, subsidiary of a long-established wagon and coach manufacturer, started to build cars in 1897[30]:p.66 and commenced sales of electric vehicles in 1902 and gasoline vehicles in 1904.[31]
+
+In Britain, there had been several attempts to build steam cars with varying degrees of success, with Thomas Rickett even attempting a production run in 1860.[32] Santler from Malvern is recognized by the Veteran Car Club of Great Britain as having made the first gasoline-powered car in the country in 1894,[33] followed by Frederick William Lanchester in 1895, but these were both one-offs.[33] The first production vehicles in Great Britain came from the Daimler Company, a company founded by Harry J. Lawson in 1896, after purchasing the right to use the name of the engines. Lawson's company made its first car in 1897, and they bore the name Daimler.[33]
+
+In 1892, German engineer Rudolf Diesel was granted a patent for a "New Rational Combustion Engine". In 1897, he built the first diesel engine.[1] Steam-, electric-, and gasoline-powered vehicles competed for decades, with gasoline internal combustion engines achieving dominance in the 1910s. Although various pistonless rotary engine designs have attempted to compete with the conventional piston and crankshaft design, only Mazda's version of the Wankel engine has had more than very limited success.
+
+All in all, it is estimated that over 100,000 patents created the modern automobile and motorcycle.[34]
+
+Large-scale, production-line manufacturing of affordable cars was started by Ransom Olds in 1901 at his Oldsmobile factory in Lansing, Michigan and based upon stationary assembly line techniques pioneered by Marc Isambard Brunel at the Portsmouth Block Mills, England, in 1802. The assembly line style of mass production and interchangeable parts had been pioneered in the U.S. by Thomas Blanchard in 1821, at the Springfield Armory in Springfield, Massachusetts.[35] This concept was greatly expanded by Henry Ford, beginning in 1913 with the world's first moving assembly line for cars at the Highland Park Ford Plant.
+
+As a result, Ford's cars came off the line in fifteen-minute intervals, much faster than previous methods, increasing productivity eightfold, while using less manpower (from 12.5-man-hours to 1 hour 33 minutes).[36] It was so successful, paint became a bottleneck. Only Japan black would dry fast enough, forcing the company to drop the variety of colors available before 1913, until fast-drying Duco lacquer was developed in 1926. This is the source of Ford's apocryphal remark, "any color as long as it's black".[36] In 1914, an assembly line worker could buy a Model T with four months' pay.[36]
+
+Ford's complex safety procedures—especially assigning each worker to a specific location instead of allowing them to roam about—dramatically reduced the rate of injury.[citation needed] The combination of high wages and high efficiency is called "Fordism," and was copied by most major industries. The efficiency gains from the assembly line also coincided with the economic rise of the United States. The assembly line forced workers to work at a certain pace with very repetitive motions which led to more output per worker while other countries were using less productive methods.
+
+In the automotive industry, its success was dominating, and quickly spread worldwide seeing the founding of Ford France and Ford Britain in 1911, Ford Denmark 1923, Ford Germany 1925; in 1921, Citroen was the first native European manufacturer to adopt the production method. Soon, companies had to have assembly lines, or risk going broke; by 1930, 250 companies which did not, had disappeared.[36]
+
+Development of automotive technology was rapid, due in part to the hundreds of small manufacturers competing to gain the world's attention. Key developments included electric ignition and the electric self-starter (both by Charles Kettering, for the Cadillac Motor Company in 1910–1911), independent suspension, and four-wheel brakes.
+
+Since the 1920s, nearly all cars have been mass-produced to meet market needs, so marketing plans often have heavily influenced car design. It was Alfred P. Sloan who established the idea of different makes of cars produced by one company, called the General Motors Companion Make Program, so that buyers could "move up" as their fortunes improved.
+
+Reflecting the rapid pace of change, makes shared parts with one another so larger production volume resulted in lower costs for each price range. For example, in the 1930s, LaSalles, sold by Cadillac, used cheaper mechanical parts made by Oldsmobile; in the 1950s, Chevrolet shared hood, doors, roof, and windows with Pontiac; by the 1990s, corporate powertrains and shared platforms (with interchangeable brakes, suspension, and other parts) were common. Even so, only major makers could afford high costs, and even companies with decades of production, such as Apperson, Cole, Dorris, Haynes, or Premier, could not manage: of some two hundred American car makers in existence in 1920, only 43 survived in 1930, and with the Great Depression, by 1940, only 17 of those were left.[36]
+
+In Europe, much the same would happen. Morris set up its production line at Cowley in 1924, and soon outsold Ford, while beginning in 1923 to follow Ford's practice of vertical integration, buying Hotchkiss (engines), Wrigley (gearboxes), and Osberton (radiators), for instance, as well as competitors, such as Wolseley: in 1925, Morris had 41% of total British car production. Most British small-car assemblers, from Abbey to Xtra, had gone under. Citroen did the same in France, coming to cars in 1919; between them and other cheap cars in reply such as Renault's 10CV and Peugeot's 5CV, they produced 550,000 cars in 1925, and Mors, Hurtu, and others could not compete.[36] Germany's first mass-manufactured car, the Opel 4PS Laubfrosch (Tree Frog), came off the line at Russelsheim in 1924, soon making Opel the top car builder in Germany, with 37.5% of the market.[36]
+
+In Japan, car production was very limited before World War II. Only a handful of companies were producing vehicles in limited numbers, and these were small, three-wheeled for commercial uses, like Daihatsu, or were the result of partnering with European companies, like Isuzu building the Wolseley A-9 in 1922. Mitsubishi was also partnered with Fiat and built the Mitsubishi Model A based on a Fiat vehicle. Toyota, Nissan, Suzuki, Mazda, and Honda began as companies producing non-automotive products before the war, switching to car production during the 1950s. Kiichiro Toyoda's decision to take Toyoda Loom Works into automobile manufacturing would create what would eventually become Toyota Motor Corporation, the largest automobile manufacturer in the world. Subaru, meanwhile, was formed from a conglomerate of six companies who banded together as Fuji Heavy Industries, as a result of having been broken up under keiretsu legislation.
+
+According to the European Environment Agency, the transport sector is a major contributor to air pollution, noise pollution and climate change.[37]
+
+Most cars in use in the 2010s run on gasoline burnt in an internal combustion engine (ICE). The International Organization of Motor Vehicle Manufacturers says that, in countries that mandate low sulfur gasoline, gasoline-fuelled cars built to late 2010s standards (such as Euro-6) emit very little local air pollution.[38][39]  Some cities ban older gasoline-fuelled cars and some countries plan to ban sales in future. However some environmental groups say this phase-out of fossil fuel vehicles must be brought forward to limit climate change. Production of gasoline fueled cars peaked in 2017.[40][41]
+
+Other hydrocarbon fossil fuels also burnt by deflagration (rather than detonation) in ICE cars include diesel, Autogas and CNG. Removal of fossil fuel subsidies,[42][43] concerns about oil dependence, tightening environmental laws and restrictions on greenhouse gas emissions are propelling work on alternative power systems for cars. This includes hybrid vehicles, plug-in electric vehicles and hydrogen vehicles. 2.1 million light electric vehicles (of all types but mainly cars) were sold in 2018, over half in China: this was an increase of 64% on the previous year, giving a global total on the road of 5.4 million.[44]  Vehicles using alternative fuels such as ethanol flexible-fuel vehicles and natural gas vehicles[clarification needed] are also gaining popularity in some countries.[citation needed] Cars for racing or speed records have sometimes employed jet or rocket engines, but these are impractical for common use.
+
+Oil consumption has increased rapidly in the 20th and 21st centuries because there are more cars; the 1985–2003 oil glut even fuelled the sales of low-economy vehicles in OECD countries. The BRIC countries are adding to this consumption.
+
+Cars are equipped with controls used for driving, passenger comfort and safety, normally operated by a combination of the use of feet and hands, and occasionally by voice on 21st century cars. These controls include a steering wheel, pedals for operating the brakes and controlling the car's speed (and, in a manual transmission car, a clutch pedal), a shift lever or stick for changing gears, and a number of buttons and dials for turning on lights, ventilation and other functions. Modern cars' controls are now standardized, such as the location for the accelerator and brake, but this was not always the case. Controls are evolving in response to new technologies, for example the electric car and the integration of mobile communications.
+
+Some of the original controls are no longer required. For example, all cars once had controls for the choke valve, clutch, ignition timing, and a crank instead of an electric starter. However new controls have also been added to vehicles, making them more complex. These include air conditioning, navigation systems, and in car entertainment. Another trend is the replacement of physical knobs and switches by secondary controls with touchscreen controls such as BMW's iDrive and Ford's MyFord Touch. Another change is that while early cars' pedals were physically linked to the brake mechanism and throttle, in the 2010s, cars have increasingly replaced these physical linkages with electronic controls.
+
+Cars are typically fitted with multiple types of lights. These include headlights, which are used to illuminate the way ahead and make the car visible to other users, so that the vehicle can be used at night; in some jurisdictions, daytime running lights; red brake lights to indicate when the brakes are applied; amber turn signal lights to indicate the turn intentions of the driver; white-colored reverse lights to illuminate the area behind the car (and indicate that the driver will be or is reversing); and on some vehicles, additional lights (e.g., side marker lights) to increase the visibility of the car. Interior lights on the ceiling of the car are usually fitted for the driver and passengers. Some vehicles also have a trunk light and, more rarely, an engine compartment light.
+
+During the late 20th and early 21st century cars increased in weight due to batteries,[46] modern steel safety cages, anti-lock brakes, airbags, and "more-powerful—if more-efficient—engines"[47] and, as of 2019[update], typically weigh between 1 and 3 tonnes.[48] Heavier cars are safer for the driver from a crash perspective, but more dangerous for other vehicles and road users.[47] The weight of a car influences fuel consumption and performance, with more weight resulting in increased fuel consumption and decreased performance. The SmartFortwo, a small city car, weighs 750–795 kg (1,655–1,755 lb). Heavier cars include full-size cars, SUVs and extended-length SUVs like the Suburban.
+
+According to research conducted by Julian Allwood of the University of Cambridge, global energy use could be greatly reduced by using lighter cars, and an average weight of 500 kg (1,100 lb) has been said to be well achievable.[49][better source needed] In some competitions such as the Shell Eco Marathon, average car weights of 45 kg (99 lb) have also been achieved.[50] These cars are only single-seaters (still falling within the definition of a car, although 4-seater cars are more common), but they nevertheless demonstrate the amount by which car weights could still be reduced, and the subsequent lower fuel use (i.e. up to a fuel use of 2560 km/l).[51]
+
+Most cars are designed to carry multiple occupants, often with four or five seats. Cars with five seats typically seat two passengers in the front and three in the rear. Full-size cars and large sport utility vehicles can often carry six, seven, or more occupants depending on the arrangement of the seats. On the other hand, sports cars are most often designed with only two seats. The differing needs for passenger capacity and their luggage or cargo space has resulted in the availability of a large variety of body styles to meet individual consumer requirements that include, among others, the sedan/saloon, hatchback, station wagon/estate, and minivan.
+
+Traffic collisions are the largest cause of injury-related deaths worldwide.[8] Mary Ward became one of the first documented car fatalities in 1869 in Parsonstown, Ireland,[52] and Henry Bliss one of the United States' first pedestrian car casualties in 1899 in New York City.[53]
+There are now standard tests for safety in new cars, such as the EuroNCAP and the US NCAP tests,[54] and insurance-industry-backed tests by the Insurance Institute for Highway Safety (IIHS).[55]
+
+The costs of car usage, which may include the cost of: acquiring the vehicle, repairs and auto maintenance, fuel, depreciation, driving time, parking fees, taxes, and insurance,[7] are weighed against the cost of the alternatives, and the value of the benefits – perceived and real – of vehicle usage. The benefits may include on-demand transportation, mobility, independence and convenience.[9] During the 1920s, cars had another benefit: "[c]ouples finally had a way to head off on unchaperoned dates, plus they had a private space to snuggle up close at the end of the night."[57]
+
+Similarly the costs to society of car use may include; maintaining roads, land use, air pollution, road congestion, public health, health care, and of disposing of the vehicle at the end of its life; and can be balanced against the value of the benefits to society that car use generates. Societal benefits may include: economy benefits, such as job and wealth creation, of car production and maintenance, transportation provision, society wellbeing derived from leisure and travel opportunities, and revenue generation from the tax opportunities. The ability of humans to move flexibly from place to place has far-reaching implications for the nature of societies.[10]
+
+Cars are a major cause of urban air pollution,[58] with all types of cars producing dust from brakes, tyres and road wear.[59]  As of 2018[update] the average diesel car has a worse effect on air quality than the average gasoline car[60] But both gasoline and diesel cars pollute more than electric cars.[61] While there are different ways to power cars most rely on gasoline or diesel, and they consume almost a quarter of world oil production as of 2019[update].[40] In 2018 passenger road vehicles emitted 3.6 gigatonnes of carbon dioxide.[62] As of 2019[update], due to greenhouse gases emitted during battery production, electric cars must be driven tens of thousands of kilometers before their lifecycle carbon emissions are less than fossil fuel cars:[63] but this is expected to improve in future due to longer lasting[64] batteries being produced in larger factories,[65] and lower carbon electricity. Many governments are using fiscal policies, such as road tax, to discourage the purchase and use of more polluting cars;[66] and many cities are doing the same with low-emission zones.[67] Fuel taxes may act as an incentive for the production of more efficient, hence less polluting, car designs (e.g. hybrid vehicles) and the development of alternative fuels. High fuel taxes or cultural change may provide a strong incentive for consumers to purchase lighter, smaller, more fuel-efficient cars, or to not drive.[67]
+
+The lifetime of a car built in the 2020s is expected to be about 16 years, or about 2 million kilometres (1.2 million miles) if driven a lot.[68] According to the International Energy Agency fuel economy improved 0.7% in 2017, but an annual improvement of 3.7% is needed to meet the Global Fuel Economy Initiative 2030 target.[69] The increase in sales of SUVs is bad for fuel economy.[40] Many cities in Europe, have banned older fossil fuel cars and all fossil fuel vehicles will be banned in Amsterdam from 2030.[70] Many Chinese cities limit licensing of fossil fuel cars,[71] and many countries plan to stop selling them between 2025 and 2050.[72]
+
+The manufacture of vehicles is resource intensive, and many manufacturers now report on the environmental performance of their factories, including energy usage, waste and water consumption.[73] Manufacturing each kWh of battery emits a similar amount of carbon as burning through one full tank of gasoline.[74] The growth in popularity of the car allowed cities to sprawl, therefore encouraging more travel by car resulting in inactivity and obesity, which in turn can lead to increased risk of a variety of diseases.[75]
+
+Animals and plants are often negatively impacted by cars via habitat destruction and pollution. Over the lifetime of the average car the "loss of habitat potential" may be over 50,000 m2 (540,000 sq ft) based on primary production correlations.[76] Animals are also killed every year on roads by cars, referred to as roadkill. More recent road developments are including significant environmental mitigation in their designs, such as green bridges (designed to allow wildlife crossings) and creating wildlife corridors.
+
+Growth in the popularity of vehicles and commuting has led to traffic congestion. Moscow, Istanbul, Bogota, Mexico City and Sao Paulo were the world's most congested cities in 2018 according to INRIX, a data analytics company.[77]
+
+Although intensive development of  conventional battery electric vehicles is continuing into the 2020s,[78] other car propulsion technologies that are under development include wheel hub motors,[79] wireless charging,[80] hydrogen cars,[81] and hydrogen/electric hybrids.[82] Research into alternative forms of power includes using ammonia instead of hydrogen in fuel cells.[83]
+
+New materials[84] which may replace steel car bodies include duralumin, fiberglass, carbon fiber, biocomposites, and carbon nanotubes. Telematics technology is allowing more and more people to share cars, on a pay-as-you-go basis, through car share and carpool schemes. Communication is also evolving due to connected car systems.[85]
+
+Fully autonomous vehicles, also known as driverless cars, already exist in prototype (such as the Google driverless car), but have a long way to go before they are in general use.
+
+There have been several projects aiming to develop a car on the principles of open design, an approach to designing in which the plans for the machinery and systems are publicly shared, often without monetary compensation. The projects include OScar, Riversimple (through 40fires.org)[86] and c,mm,n.[87] None of the projects have reached significant success in terms of developing a car as a whole both from hardware and software perspective and no mass production ready open-source based design have been introduced as of late 2009. Some car hacking through on-board diagnostics (OBD) has been done so far.[88]
+
+Car-share arrangements and carpooling are also increasingly popular, in the US and Europe.[89] For example, in the US, some car-sharing services have experienced double-digit growth in revenue and membership growth between 2006 and 2007. Services like car sharing offering a residents to "share" a vehicle rather than own a car in already congested neighborhoods.[90]
+
+The automotive industry designs, develops, manufactures, markets, and sells the world's motor vehicles, more than three-quarters of which are cars. In 2018 there were 70 million cars manufactured worldwide,[91] down 2 million from the previous year.[92]
+
+The automotive industry in China produces by far the most (24 million in 2018), followed by Japan (8 million), Germany (5 million) and India (4 million).[91] The largest market is China, followed by the USA.
+
+Around the world there are about a billion cars on the road;[93] they burn over a trillion liters of gasoline and diesel fuel yearly, consuming about 50 EJ (nearly 300 terawatt-hours) of energy.[94] The numbers of cars are increasing rapidly in China and India.[11] In the opinion of some, urban transport systems based around the car have proved unsustainable, consuming excessive energy, affecting the health of populations, and delivering a declining level of service despite increasing investment. Many of these negative impacts fall disproportionately on those social groups who are also least likely to own and drive cars.[95][96] The sustainable transport movement focuses on solutions to these problems. The car industry is also facing increasing competition from the public transport sector, as some people re-evaluate their private vehicle usage.
+
+Established alternatives for some aspects of car use include public transport such as buses, trolleybuses, trains, subways, tramways, light rail, cycling, and walking. Bicycle sharing systems have been established in China and many European cities, including Copenhagen and Amsterdam. Similar programs have been developed in large US cities.[98][99] Additional individual modes of transport, such as personal rapid transit could serve as an alternative to cars if they prove to be socially accepted.[100]
+
+The term motorcar was formerly also used in the context of electrified rail systems to denote a car which functions as a small locomotive but also provides space for passengers and baggage.  These locomotive cars were often used on suburban routes by both interurban and intercity railroad systems.[101]

en/6029.html.txt

@@ -0,0 +1,122 @@
+
+
+A car (or automobile) is a wheeled motor vehicle used for transportation.  Most definitions of cars say that they run primarily on roads, seat one to eight people, have four tires, and mainly transport people rather than goods.[2][3]
+
+Cars came into global use during the 20th century, and developed economies depend on them. The year 1886 is regarded as the birth year of the modern car when German inventor Karl Benz patented his Benz Patent-Motorwagen. Cars became widely available in the early 20th century. One of the first cars accessible to the masses was the 1908 Model T, an American car manufactured by the Ford Motor Company. Cars were rapidly adopted in the US, where they replaced animal-drawn carriages and carts, but took much longer to be accepted in Western Europe and other parts of the world.[citation needed]
+
+Cars have controls for driving, parking, passenger comfort, and a variety of lights. Over the decades, additional features and controls have been added to vehicles, making them progressively more complex, but also more reliable and easier to operate.[citation needed] These include rear-reversing cameras, air conditioning, navigation systems, and in-car entertainment. Most cars in use in the 2010s are propelled by an internal combustion engine, fueled by the combustion of fossil fuels. Electric cars, which were invented early in the history of the car, became commercially available in the 2000s and are predicted to cost less to buy than gasoline cars before 2025.[4][5] The transition from fossil fuels to electric cars features prominently in most climate change mitigation scenarios.[6]
+
+There are costs and benefits to car use. The costs to the individual include acquiring the vehicle, interest payments (if the car is financed), repairs and maintenance, fuel, depreciation, driving time, parking fees, taxes, and insurance.[7] The costs to society include maintaining roads, land use, road congestion, air pollution, public health, healthcare, and disposing of the vehicle at the end of its life. Traffic collisions are the largest cause of injury-related deaths worldwide.[8]
+
+The personal benefits include on-demand transportation, mobility, independence, and convenience.[9] The societal benefits include economic benefits, such as job and wealth creation from the automotive industry, transportation provision, societal well-being from leisure and travel opportunities, and revenue generation from the taxes. People's ability to move flexibly from place to place has far-reaching implications for the nature of societies.[10] There are around 1 billion cars in use worldwide. The numbers are increasing rapidly, especially in China, India and other newly industrialized countries.[11]
+
+The English word car is believed to originate from Latin carrus/carrum "wheeled vehicle" or (via Old North French) Middle English carre "two-wheeled cart," both of which in turn derive from Gaulish karros "chariot."[12][13] It originally referred to any wheeled horse-drawn vehicle, such as a cart, carriage, or wagon.[14][15]
+
+"Motor car," attested from 1895, is the usual formal term in British English.[3] "Autocar," a variant likewise attested from 1895 and literally meaning "self-propelled car," is now considered archaic.[16] "Horseless carriage" is attested from 1895.[17]
+
+"Automobile," a classical compound derived from Ancient Greek autós (αὐτός) "self" and Latin mobilis "movable," entered English from French and was first adopted by the Automobile Club of Great Britain in 1897.[18] It fell out of favour in Britain and is now used chiefly in North America,[19] where the abbreviated form "auto" commonly appears as an adjective in compound formations like "auto industry" and "auto mechanic".[20][21] Both forms are still used in everyday Dutch (auto/automobiel) and German (Auto/Automobil).[citation needed]
+
+The first working steam-powered vehicle was designed — and quite possibly built — by Ferdinand Verbiest, a Flemish member of a Jesuit mission in China around 1672. It was a 65-cm-long scale-model toy for the Chinese Emperor that was unable to carry a driver or a passenger.[9][22][23] It is not known with certainty if Verbiest's model was successfully built or run.[23]
+
+Nicolas-Joseph Cugnot is widely credited with building the first full-scale, self-propelled mechanical vehicle or car in about 1769; he created a steam-powered tricycle.[24]  He also constructed two steam tractors for the French Army, one of which is preserved in the French National Conservatory of Arts and Crafts.[25] His inventions were, however, handicapped by problems with water supply and maintaining steam pressure.[25] In 1801, Richard Trevithick built and demonstrated his Puffing Devil road locomotive, believed by many to be the first demonstration of a steam-powered road vehicle. It was unable to maintain sufficient steam pressure for long periods and was of little practical use.
+
+The development of external combustion engines is detailed as part of the history of the car but often treated separately from the development of true cars.  A variety of steam-powered road vehicles were used during the first part of the 19th century, including steam cars, steam buses, phaetons, and steam rollers.  Sentiment against them led to the Locomotive Acts of 1865.
+
+In 1807, Nicéphore Niépce and his brother Claude created what was probably the world's first internal combustion engine (which they called a Pyréolophore), but they chose to install it in a boat on the river Saone in France.[26] Coincidentally, in 1807 the Swiss inventor François Isaac de Rivaz designed his own 'de Rivaz internal combustion engine' and used it to develop the world's first vehicle to be powered by such an engine. The Niépces' Pyréolophore was fuelled by a mixture of Lycopodium powder (dried spores of the Lycopodium plant), finely crushed coal dust and resin that were mixed with oil, whereas de Rivaz used a mixture of hydrogen and oxygen.[26] Neither design was very successful, as was the case with others, such as Samuel Brown, Samuel Morey, and Etienne Lenoir with his hippomobile, who each produced vehicles (usually adapted carriages or carts) powered by internal combustion engines.[1]
+
+In November 1881, French inventor Gustave Trouvé demonstrated the first working (three-wheeled) car powered by electricity at the International Exposition of Electricity, Paris.[27] Although several other German engineers (including Gottlieb Daimler, Wilhelm Maybach, and Siegfried Marcus) were working on the problem at about the same time, Karl Benz generally is acknowledged as the inventor of the modern car.[1]
+
+In 1879, Benz was granted a patent for his first engine, which had been designed in 1878. Many of his other inventions made the use of the internal combustion engine feasible for powering a vehicle. His first Motorwagen was built in 1885 in Mannheim, Germany. He was awarded the patent for its invention as of his application on 29 January 1886 (under the auspices of his major company, Benz & Cie., which was founded in 1883). Benz began promotion of the vehicle on 3 July 1886, and about 25 Benz vehicles were sold between 1888 and 1893, when his first four-wheeler was introduced along with a cheaper model. They also were powered with four-stroke engines of his own design. Emile Roger of France, already producing Benz engines under license, now added the Benz car to his line of products. Because France was more open to the early cars, initially more were built and sold in France through Roger than Benz sold in Germany. In August 1888 Bertha Benz, the wife of Karl Benz, undertook the first road trip by car, to prove the road-worthiness of her husband's invention.
+
+In 1896, Benz designed and patented the first internal-combustion flat engine, called boxermotor. During the last years of the nineteenth century, Benz was the largest car company in the world with 572 units produced in 1899 and, because of its size, Benz & Cie., became a joint-stock company. The first motor car in central Europe and one of the first factory-made cars in the world, was produced by Czech company Nesselsdorfer Wagenbau (later renamed to Tatra) in 1897, the Präsident automobil.
+
+Daimler and Maybach founded Daimler Motoren Gesellschaft (DMG) in Cannstatt in 1890, and sold their first car in 1892 under the brand name Daimler. It was a horse-drawn stagecoach built by another manufacturer, which they retrofitted with an engine of their design. By 1895 about 30 vehicles had been built by Daimler and Maybach, either at the Daimler works or in the Hotel Hermann, where they set up shop after disputes with their backers. Benz, Maybach and the Daimler team seem to have been unaware of each other's early work. They never worked together; by the time of the merger of the two companies, Daimler and Maybach were no longer part of DMG. Daimler died in 1900 and later that year, Maybach designed an engine named Daimler-Mercedes that was placed in a specially ordered model built to specifications set by Emil Jellinek. This was a production of a small number of vehicles for Jellinek to race and market in his country. Two years later, in 1902, a new model DMG car was produced and the model was named Mercedes after the Maybach engine, which generated 35 hp. Maybach quit DMG shortly thereafter and opened a business of his own. Rights to the Daimler brand name were sold to other manufacturers.
+
+Karl Benz proposed co-operation between DMG and Benz & Cie. when economic conditions began to deteriorate in Germany following the First World War, but the directors of DMG refused to consider it initially. Negotiations between the two companies resumed several years later when these conditions worsened and, in 1924 they signed an Agreement of Mutual Interest, valid until the year 2000. Both enterprises standardized design, production, purchasing, and sales and they advertised or marketed their car models jointly, although keeping their respective brands. On 28 June 1926, Benz & Cie. and DMG finally merged as the Daimler-Benz company, baptizing all of its cars Mercedes Benz, as a brand honoring the most important model of the DMG cars, the Maybach design later referred to as the 1902 Mercedes-35 hp, along with the Benz name. Karl Benz remained a member of the board of directors of Daimler-Benz until his death in 1929, and at times, his two sons also participated in the management of the company.
+
+In 1890, Émile Levassor and Armand Peugeot of France began producing vehicles with Daimler engines, and so laid the foundation of the automotive industry in France. In 1891, Auguste Doriot and his Peugeot colleague Louis Rigoulot completed the longest trip by a gasoline-powered vehicle when their self-designed and built Daimler powered Peugeot Type 3 completed 2,100 km (1,300 miles) from Valentigney to Paris and Brest and back again. They were attached to the first Paris–Brest–Paris bicycle race, but finished 6 days after the winning cyclist, Charles Terront.
+
+The first design for an American car with a gasoline internal combustion engine was made in 1877 by George Selden of Rochester, New York. Selden applied for a patent for a car in 1879, but the patent application expired because the vehicle was never built. After a delay of sixteen years and a series of attachments to his application, on 5 November 1895, Selden was granted a United States patent (U.S. Patent 549,160) for a two-stroke car engine, which hindered, more than encouraged, development of cars in the United States. His patent was challenged by Henry Ford and others, and overturned in 1911.
+
+In 1893, the first running, gasoline-powered American car was built and road-tested by the Duryea brothers of Springfield, Massachusetts. The first public run of the Duryea Motor Wagon took place on 21 September 1893, on Taylor Street in Metro Center Springfield.[28][29] The Studebaker Automobile Company, subsidiary of a long-established wagon and coach manufacturer, started to build cars in 1897[30]:p.66 and commenced sales of electric vehicles in 1902 and gasoline vehicles in 1904.[31]
+
+In Britain, there had been several attempts to build steam cars with varying degrees of success, with Thomas Rickett even attempting a production run in 1860.[32] Santler from Malvern is recognized by the Veteran Car Club of Great Britain as having made the first gasoline-powered car in the country in 1894,[33] followed by Frederick William Lanchester in 1895, but these were both one-offs.[33] The first production vehicles in Great Britain came from the Daimler Company, a company founded by Harry J. Lawson in 1896, after purchasing the right to use the name of the engines. Lawson's company made its first car in 1897, and they bore the name Daimler.[33]
+
+In 1892, German engineer Rudolf Diesel was granted a patent for a "New Rational Combustion Engine". In 1897, he built the first diesel engine.[1] Steam-, electric-, and gasoline-powered vehicles competed for decades, with gasoline internal combustion engines achieving dominance in the 1910s. Although various pistonless rotary engine designs have attempted to compete with the conventional piston and crankshaft design, only Mazda's version of the Wankel engine has had more than very limited success.
+
+All in all, it is estimated that over 100,000 patents created the modern automobile and motorcycle.[34]
+
+Large-scale, production-line manufacturing of affordable cars was started by Ransom Olds in 1901 at his Oldsmobile factory in Lansing, Michigan and based upon stationary assembly line techniques pioneered by Marc Isambard Brunel at the Portsmouth Block Mills, England, in 1802. The assembly line style of mass production and interchangeable parts had been pioneered in the U.S. by Thomas Blanchard in 1821, at the Springfield Armory in Springfield, Massachusetts.[35] This concept was greatly expanded by Henry Ford, beginning in 1913 with the world's first moving assembly line for cars at the Highland Park Ford Plant.
+
+As a result, Ford's cars came off the line in fifteen-minute intervals, much faster than previous methods, increasing productivity eightfold, while using less manpower (from 12.5-man-hours to 1 hour 33 minutes).[36] It was so successful, paint became a bottleneck. Only Japan black would dry fast enough, forcing the company to drop the variety of colors available before 1913, until fast-drying Duco lacquer was developed in 1926. This is the source of Ford's apocryphal remark, "any color as long as it's black".[36] In 1914, an assembly line worker could buy a Model T with four months' pay.[36]
+
+Ford's complex safety procedures—especially assigning each worker to a specific location instead of allowing them to roam about—dramatically reduced the rate of injury.[citation needed] The combination of high wages and high efficiency is called "Fordism," and was copied by most major industries. The efficiency gains from the assembly line also coincided with the economic rise of the United States. The assembly line forced workers to work at a certain pace with very repetitive motions which led to more output per worker while other countries were using less productive methods.
+
+In the automotive industry, its success was dominating, and quickly spread worldwide seeing the founding of Ford France and Ford Britain in 1911, Ford Denmark 1923, Ford Germany 1925; in 1921, Citroen was the first native European manufacturer to adopt the production method. Soon, companies had to have assembly lines, or risk going broke; by 1930, 250 companies which did not, had disappeared.[36]
+
+Development of automotive technology was rapid, due in part to the hundreds of small manufacturers competing to gain the world's attention. Key developments included electric ignition and the electric self-starter (both by Charles Kettering, for the Cadillac Motor Company in 1910–1911), independent suspension, and four-wheel brakes.
+
+Since the 1920s, nearly all cars have been mass-produced to meet market needs, so marketing plans often have heavily influenced car design. It was Alfred P. Sloan who established the idea of different makes of cars produced by one company, called the General Motors Companion Make Program, so that buyers could "move up" as their fortunes improved.
+
+Reflecting the rapid pace of change, makes shared parts with one another so larger production volume resulted in lower costs for each price range. For example, in the 1930s, LaSalles, sold by Cadillac, used cheaper mechanical parts made by Oldsmobile; in the 1950s, Chevrolet shared hood, doors, roof, and windows with Pontiac; by the 1990s, corporate powertrains and shared platforms (with interchangeable brakes, suspension, and other parts) were common. Even so, only major makers could afford high costs, and even companies with decades of production, such as Apperson, Cole, Dorris, Haynes, or Premier, could not manage: of some two hundred American car makers in existence in 1920, only 43 survived in 1930, and with the Great Depression, by 1940, only 17 of those were left.[36]
+
+In Europe, much the same would happen. Morris set up its production line at Cowley in 1924, and soon outsold Ford, while beginning in 1923 to follow Ford's practice of vertical integration, buying Hotchkiss (engines), Wrigley (gearboxes), and Osberton (radiators), for instance, as well as competitors, such as Wolseley: in 1925, Morris had 41% of total British car production. Most British small-car assemblers, from Abbey to Xtra, had gone under. Citroen did the same in France, coming to cars in 1919; between them and other cheap cars in reply such as Renault's 10CV and Peugeot's 5CV, they produced 550,000 cars in 1925, and Mors, Hurtu, and others could not compete.[36] Germany's first mass-manufactured car, the Opel 4PS Laubfrosch (Tree Frog), came off the line at Russelsheim in 1924, soon making Opel the top car builder in Germany, with 37.5% of the market.[36]
+
+In Japan, car production was very limited before World War II. Only a handful of companies were producing vehicles in limited numbers, and these were small, three-wheeled for commercial uses, like Daihatsu, or were the result of partnering with European companies, like Isuzu building the Wolseley A-9 in 1922. Mitsubishi was also partnered with Fiat and built the Mitsubishi Model A based on a Fiat vehicle. Toyota, Nissan, Suzuki, Mazda, and Honda began as companies producing non-automotive products before the war, switching to car production during the 1950s. Kiichiro Toyoda's decision to take Toyoda Loom Works into automobile manufacturing would create what would eventually become Toyota Motor Corporation, the largest automobile manufacturer in the world. Subaru, meanwhile, was formed from a conglomerate of six companies who banded together as Fuji Heavy Industries, as a result of having been broken up under keiretsu legislation.
+
+According to the European Environment Agency, the transport sector is a major contributor to air pollution, noise pollution and climate change.[37]
+
+Most cars in use in the 2010s run on gasoline burnt in an internal combustion engine (ICE). The International Organization of Motor Vehicle Manufacturers says that, in countries that mandate low sulfur gasoline, gasoline-fuelled cars built to late 2010s standards (such as Euro-6) emit very little local air pollution.[38][39]  Some cities ban older gasoline-fuelled cars and some countries plan to ban sales in future. However some environmental groups say this phase-out of fossil fuel vehicles must be brought forward to limit climate change. Production of gasoline fueled cars peaked in 2017.[40][41]
+
+Other hydrocarbon fossil fuels also burnt by deflagration (rather than detonation) in ICE cars include diesel, Autogas and CNG. Removal of fossil fuel subsidies,[42][43] concerns about oil dependence, tightening environmental laws and restrictions on greenhouse gas emissions are propelling work on alternative power systems for cars. This includes hybrid vehicles, plug-in electric vehicles and hydrogen vehicles. 2.1 million light electric vehicles (of all types but mainly cars) were sold in 2018, over half in China: this was an increase of 64% on the previous year, giving a global total on the road of 5.4 million.[44]  Vehicles using alternative fuels such as ethanol flexible-fuel vehicles and natural gas vehicles[clarification needed] are also gaining popularity in some countries.[citation needed] Cars for racing or speed records have sometimes employed jet or rocket engines, but these are impractical for common use.
+
+Oil consumption has increased rapidly in the 20th and 21st centuries because there are more cars; the 1985–2003 oil glut even fuelled the sales of low-economy vehicles in OECD countries. The BRIC countries are adding to this consumption.
+
+Cars are equipped with controls used for driving, passenger comfort and safety, normally operated by a combination of the use of feet and hands, and occasionally by voice on 21st century cars. These controls include a steering wheel, pedals for operating the brakes and controlling the car's speed (and, in a manual transmission car, a clutch pedal), a shift lever or stick for changing gears, and a number of buttons and dials for turning on lights, ventilation and other functions. Modern cars' controls are now standardized, such as the location for the accelerator and brake, but this was not always the case. Controls are evolving in response to new technologies, for example the electric car and the integration of mobile communications.
+
+Some of the original controls are no longer required. For example, all cars once had controls for the choke valve, clutch, ignition timing, and a crank instead of an electric starter. However new controls have also been added to vehicles, making them more complex. These include air conditioning, navigation systems, and in car entertainment. Another trend is the replacement of physical knobs and switches by secondary controls with touchscreen controls such as BMW's iDrive and Ford's MyFord Touch. Another change is that while early cars' pedals were physically linked to the brake mechanism and throttle, in the 2010s, cars have increasingly replaced these physical linkages with electronic controls.
+
+Cars are typically fitted with multiple types of lights. These include headlights, which are used to illuminate the way ahead and make the car visible to other users, so that the vehicle can be used at night; in some jurisdictions, daytime running lights; red brake lights to indicate when the brakes are applied; amber turn signal lights to indicate the turn intentions of the driver; white-colored reverse lights to illuminate the area behind the car (and indicate that the driver will be or is reversing); and on some vehicles, additional lights (e.g., side marker lights) to increase the visibility of the car. Interior lights on the ceiling of the car are usually fitted for the driver and passengers. Some vehicles also have a trunk light and, more rarely, an engine compartment light.
+
+During the late 20th and early 21st century cars increased in weight due to batteries,[46] modern steel safety cages, anti-lock brakes, airbags, and "more-powerful—if more-efficient—engines"[47] and, as of 2019[update], typically weigh between 1 and 3 tonnes.[48] Heavier cars are safer for the driver from a crash perspective, but more dangerous for other vehicles and road users.[47] The weight of a car influences fuel consumption and performance, with more weight resulting in increased fuel consumption and decreased performance. The SmartFortwo, a small city car, weighs 750–795 kg (1,655–1,755 lb). Heavier cars include full-size cars, SUVs and extended-length SUVs like the Suburban.
+
+According to research conducted by Julian Allwood of the University of Cambridge, global energy use could be greatly reduced by using lighter cars, and an average weight of 500 kg (1,100 lb) has been said to be well achievable.[49][better source needed] In some competitions such as the Shell Eco Marathon, average car weights of 45 kg (99 lb) have also been achieved.[50] These cars are only single-seaters (still falling within the definition of a car, although 4-seater cars are more common), but they nevertheless demonstrate the amount by which car weights could still be reduced, and the subsequent lower fuel use (i.e. up to a fuel use of 2560 km/l).[51]
+
+Most cars are designed to carry multiple occupants, often with four or five seats. Cars with five seats typically seat two passengers in the front and three in the rear. Full-size cars and large sport utility vehicles can often carry six, seven, or more occupants depending on the arrangement of the seats. On the other hand, sports cars are most often designed with only two seats. The differing needs for passenger capacity and their luggage or cargo space has resulted in the availability of a large variety of body styles to meet individual consumer requirements that include, among others, the sedan/saloon, hatchback, station wagon/estate, and minivan.
+
+Traffic collisions are the largest cause of injury-related deaths worldwide.[8] Mary Ward became one of the first documented car fatalities in 1869 in Parsonstown, Ireland,[52] and Henry Bliss one of the United States' first pedestrian car casualties in 1899 in New York City.[53]
+There are now standard tests for safety in new cars, such as the EuroNCAP and the US NCAP tests,[54] and insurance-industry-backed tests by the Insurance Institute for Highway Safety (IIHS).[55]
+
+The costs of car usage, which may include the cost of: acquiring the vehicle, repairs and auto maintenance, fuel, depreciation, driving time, parking fees, taxes, and insurance,[7] are weighed against the cost of the alternatives, and the value of the benefits – perceived and real – of vehicle usage. The benefits may include on-demand transportation, mobility, independence and convenience.[9] During the 1920s, cars had another benefit: "[c]ouples finally had a way to head off on unchaperoned dates, plus they had a private space to snuggle up close at the end of the night."[57]
+
+Similarly the costs to society of car use may include; maintaining roads, land use, air pollution, road congestion, public health, health care, and of disposing of the vehicle at the end of its life; and can be balanced against the value of the benefits to society that car use generates. Societal benefits may include: economy benefits, such as job and wealth creation, of car production and maintenance, transportation provision, society wellbeing derived from leisure and travel opportunities, and revenue generation from the tax opportunities. The ability of humans to move flexibly from place to place has far-reaching implications for the nature of societies.[10]
+
+Cars are a major cause of urban air pollution,[58] with all types of cars producing dust from brakes, tyres and road wear.[59]  As of 2018[update] the average diesel car has a worse effect on air quality than the average gasoline car[60] But both gasoline and diesel cars pollute more than electric cars.[61] While there are different ways to power cars most rely on gasoline or diesel, and they consume almost a quarter of world oil production as of 2019[update].[40] In 2018 passenger road vehicles emitted 3.6 gigatonnes of carbon dioxide.[62] As of 2019[update], due to greenhouse gases emitted during battery production, electric cars must be driven tens of thousands of kilometers before their lifecycle carbon emissions are less than fossil fuel cars:[63] but this is expected to improve in future due to longer lasting[64] batteries being produced in larger factories,[65] and lower carbon electricity. Many governments are using fiscal policies, such as road tax, to discourage the purchase and use of more polluting cars;[66] and many cities are doing the same with low-emission zones.[67] Fuel taxes may act as an incentive for the production of more efficient, hence less polluting, car designs (e.g. hybrid vehicles) and the development of alternative fuels. High fuel taxes or cultural change may provide a strong incentive for consumers to purchase lighter, smaller, more fuel-efficient cars, or to not drive.[67]
+
+The lifetime of a car built in the 2020s is expected to be about 16 years, or about 2 million kilometres (1.2 million miles) if driven a lot.[68] According to the International Energy Agency fuel economy improved 0.7% in 2017, but an annual improvement of 3.7% is needed to meet the Global Fuel Economy Initiative 2030 target.[69] The increase in sales of SUVs is bad for fuel economy.[40] Many cities in Europe, have banned older fossil fuel cars and all fossil fuel vehicles will be banned in Amsterdam from 2030.[70] Many Chinese cities limit licensing of fossil fuel cars,[71] and many countries plan to stop selling them between 2025 and 2050.[72]
+
+The manufacture of vehicles is resource intensive, and many manufacturers now report on the environmental performance of their factories, including energy usage, waste and water consumption.[73] Manufacturing each kWh of battery emits a similar amount of carbon as burning through one full tank of gasoline.[74] The growth in popularity of the car allowed cities to sprawl, therefore encouraging more travel by car resulting in inactivity and obesity, which in turn can lead to increased risk of a variety of diseases.[75]
+
+Animals and plants are often negatively impacted by cars via habitat destruction and pollution. Over the lifetime of the average car the "loss of habitat potential" may be over 50,000 m2 (540,000 sq ft) based on primary production correlations.[76] Animals are also killed every year on roads by cars, referred to as roadkill. More recent road developments are including significant environmental mitigation in their designs, such as green bridges (designed to allow wildlife crossings) and creating wildlife corridors.
+
+Growth in the popularity of vehicles and commuting has led to traffic congestion. Moscow, Istanbul, Bogota, Mexico City and Sao Paulo were the world's most congested cities in 2018 according to INRIX, a data analytics company.[77]
+
+Although intensive development of  conventional battery electric vehicles is continuing into the 2020s,[78] other car propulsion technologies that are under development include wheel hub motors,[79] wireless charging,[80] hydrogen cars,[81] and hydrogen/electric hybrids.[82] Research into alternative forms of power includes using ammonia instead of hydrogen in fuel cells.[83]
+
+New materials[84] which may replace steel car bodies include duralumin, fiberglass, carbon fiber, biocomposites, and carbon nanotubes. Telematics technology is allowing more and more people to share cars, on a pay-as-you-go basis, through car share and carpool schemes. Communication is also evolving due to connected car systems.[85]
+
+Fully autonomous vehicles, also known as driverless cars, already exist in prototype (such as the Google driverless car), but have a long way to go before they are in general use.
+
+There have been several projects aiming to develop a car on the principles of open design, an approach to designing in which the plans for the machinery and systems are publicly shared, often without monetary compensation. The projects include OScar, Riversimple (through 40fires.org)[86] and c,mm,n.[87] None of the projects have reached significant success in terms of developing a car as a whole both from hardware and software perspective and no mass production ready open-source based design have been introduced as of late 2009. Some car hacking through on-board diagnostics (OBD) has been done so far.[88]
+
+Car-share arrangements and carpooling are also increasingly popular, in the US and Europe.[89] For example, in the US, some car-sharing services have experienced double-digit growth in revenue and membership growth between 2006 and 2007. Services like car sharing offering a residents to "share" a vehicle rather than own a car in already congested neighborhoods.[90]
+
+The automotive industry designs, develops, manufactures, markets, and sells the world's motor vehicles, more than three-quarters of which are cars. In 2018 there were 70 million cars manufactured worldwide,[91] down 2 million from the previous year.[92]
+
+The automotive industry in China produces by far the most (24 million in 2018), followed by Japan (8 million), Germany (5 million) and India (4 million).[91] The largest market is China, followed by the USA.
+
+Around the world there are about a billion cars on the road;[93] they burn over a trillion liters of gasoline and diesel fuel yearly, consuming about 50 EJ (nearly 300 terawatt-hours) of energy.[94] The numbers of cars are increasing rapidly in China and India.[11] In the opinion of some, urban transport systems based around the car have proved unsustainable, consuming excessive energy, affecting the health of populations, and delivering a declining level of service despite increasing investment. Many of these negative impacts fall disproportionately on those social groups who are also least likely to own and drive cars.[95][96] The sustainable transport movement focuses on solutions to these problems. The car industry is also facing increasing competition from the public transport sector, as some people re-evaluate their private vehicle usage.
+
+Established alternatives for some aspects of car use include public transport such as buses, trolleybuses, trains, subways, tramways, light rail, cycling, and walking. Bicycle sharing systems have been established in China and many European cities, including Copenhagen and Amsterdam. Similar programs have been developed in large US cities.[98][99] Additional individual modes of transport, such as personal rapid transit could serve as an alternative to cars if they prove to be socially accepted.[100]
+
+The term motorcar was formerly also used in the context of electrified rail systems to denote a car which functions as a small locomotive but also provides space for passengers and baggage.  These locomotive cars were often used on suburban routes by both interurban and intercity railroad systems.[101]

en/603.html.txt

@@ -0,0 +1,280 @@
+
+
+The Beatles were an English rock band formed in Liverpool in 1960. The group, whose best-known line-up comprised John Lennon, Paul McCartney, George Harrison and Ringo Starr, are regarded as the most influential band of all time.[1] They were integral to the development of 1960s counterculture and popular music's recognition as an art form.[2] Rooted in skiffle, beat and 1950s rock and roll, their sound incorporated elements of classical music and traditional pop in innovative ways; the band later explored music styles ranging from ballads and Indian music to psychedelia and hard rock. As pioneers in recording, songwriting and artistic presentation, the Beatles revolutionised many aspects of the music industry and were often publicised as leaders of the era's youth and sociocultural movements.[3]
+
+Led by primary songwriters Lennon and McCartney, the Beatles built their reputation playing clubs in Liverpool and Hamburg over three years from 1960, initially with Stuart Sutcliffe playing bass. The core trio of Lennon, McCartney and Harrison, together since 1958, went through a succession of drummers, including Pete Best, before asking Starr to join them in 1962. Manager Brian Epstein moulded them into a professional act, and producer George Martin guided and developed their recordings, greatly expanding their domestic success after their first hit, "Love Me Do", in late 1962. As their popularity grew into the intense fan frenzy dubbed "Beatlemania", the band acquired the nickname "the Fab Four", with Epstein, Martin and other members of the band's entourage sometimes given the informal title of "fifth Beatle".
+
+By early 1964, the Beatles were international stars, leading the "British Invasion" of the United States pop market and breaking numerous sales records. They soon made their film debut with A Hard Day's Night (1964). From 1965 onwards, they produced records of greater complexity, including the albums Rubber Soul (1965), Revolver (1966) and Sgt. Pepper's Lonely Hearts Club Band (1967), and enjoyed further commercial success with The Beatles (also known as "the White Album", 1968) and Abbey Road (1969). In 1968, they founded Apple Corps, a multi-armed multimedia corporation that continues to oversee projects related to the band's legacy. After the group's break-up in 1970, all four members enjoyed success as solo artists. Lennon was shot and killed in December 1980, and Harrison died of lung cancer in November 2001. McCartney and Starr remain musically active.
+
+The Beatles are the best-selling music act of all time, with estimated sales of 600 million units worldwide.[4] They are the best-selling act in the US, with certified sales of 183 million units. They hold the record for most number-one albums on the UK Albums Chart, most number-one hits on the Billboard Hot 100 chart, and most singles sold in the UK. The group were inducted into the Rock and Roll Hall of Fame in 1988, and all four main members were inducted individually between 1994 and 2015. In 2008, the group topped Billboard's list of the all-time most successful artists on the Billboard Hot 100. The band received seven Grammy Awards, four Brit Awards, an Academy Award (for Best Original Song Score for the 1970 film Let It Be) and fifteen Ivor Novello Awards. Time magazine named them among the 20th century's 100 most important people.
+
+In March 1957, John Lennon, then aged sixteen, formed a skiffle group with several friends from Quarry Bank High School in Liverpool. They briefly called themselves the Blackjacks, before changing their name to the Quarrymen after discovering that another local group were already using the name.[5] Fifteen-year-old Paul McCartney joined them as a rhythm guitarist shortly after he and Lennon met that July.[6] In February 1958, McCartney invited his friend George Harrison to watch the band. The fifteen-year-old auditioned for Lennon, impressing him with his playing, but Lennon initially thought Harrison was too young for the band. After a month of Harrison's persistence, during a second meeting (arranged by McCartney), he performed the lead guitar part of the instrumental song "Raunchy" on the upper deck of a Liverpool bus,[7] and they enlisted him as their lead guitarist.[8][9]
+
+By January 1959, Lennon's Quarry Bank friends had left the group, and he began his studies at the Liverpool College of Art.[10] The three guitarists, billing themselves as Johnny and the Moondogs,[11] were playing rock and roll whenever they could find a drummer.[12] Lennon's art school friend Stuart Sutcliffe, who had just sold one of his paintings and was persuaded to purchase a bass guitar with the proceeds, joined in January 1960, and it was he who suggested changing the band's name to Beatals, as a tribute to Buddy Holly and the Crickets.[13][14] They used this name until May, when they became the Silver Beetles, before undertaking a brief tour of Scotland as the backing group for pop singer and fellow Liverpudlian Johnny Gentle. By early July, they had refashioned themselves as the Silver Beatles, and by the middle of August shortened the name to the Beatles.[15]
+
+Allan Williams, the Beatles' unofficial manager, arranged a residency for them in Hamburg, and for this they auditioned and hired drummer Pete Best in mid-August 1960. The band, now a five-piece, departed Liverpool for Hamburg four days later, contracted to club owner Bruno Koschmider for what would be a 3​1⁄2-month residency.[16] Beatles historian Mark Lewisohn writes: "They pulled into Hamburg at dusk on 17 August, the time when the red-light area comes to life ... flashing neon lights screamed out the various entertainment on offer, while scantily clad women sat unabashed in shop windows waiting for business opportunities."[17]
+
+Koschmider had converted a couple of strip clubs in the district into music venues, and he initially placed the Beatles at the Indra Club. After closing Indra due to noise complaints, he moved them to the Kaiserkeller in October.[18] When he learned they had been performing at the rival Top Ten Club in breach of their contract, he gave the band one month's termination notice,[19] and reported the underage Harrison, who had obtained permission to stay in Hamburg by lying to the German authorities about his age.[20] The authorities arranged for Harrison's deportation in late November.[21] One week later, Koschmider had McCartney and Best arrested for arson after they set fire to a condom in a concrete corridor; the authorities deported them.[22] Lennon returned to Liverpool in early December, while Sutcliffe remained in Hamburg until late February with his German fiancée Astrid Kirchherr,[23] who took the first semi-professional photos of the Beatles.[24]
+
+During the next two years, the Beatles were resident for periods in Hamburg, where they used Preludin both recreationally and to maintain their energy through all-night performances.[25] In 1961, during their second Hamburg engagement, Kirchherr cut Sutcliffe's hair in the "exi" (existentialist) style, later adopted by the other Beatles.[26][27] When Sutcliffe decided to leave the band early that year and resume his art studies in Germany, McCartney took up the bass.[28] Producer Bert Kaempfert contracted what was now a four-piece group until June 1962, and he used them as Tony Sheridan's backing band on a series of recordings for Polydor Records.[14][29] As part of the sessions, the Beatles were signed to Polydor for one year.[30] Credited to "Tony Sheridan & the Beat Brothers", the single "My Bonnie", recorded in June 1961 and released four months later, reached number 32 on the Musikmarkt chart.[31]
+
+After the Beatles completed their second Hamburg residency, they enjoyed increasing popularity in Liverpool with the growing Merseybeat movement. However, they were also growing tired of the monotony of numerous appearances at the same clubs night after night.[32] In November 1961, during one of the group's frequent performances at The Cavern Club, they encountered Brian Epstein, a local record-store owner and music columnist.[33] He later recalled: "I immediately liked what I heard. They were fresh, and they were honest, and they had what I thought was a sort of presence ... [a] star quality."[34]
+
+Epstein courted the band over the next couple of months, and they appointed him as their manager in January 1962.[35] Throughout early and mid-1962, Epstein sought to free the Beatles from their contractual obligations to Bert Kaempfert Productions. He eventually negotiated a one-month-early release from their contract in exchange for one last recording session in Hamburg.[36] Tragedy greeted them on their return to Germany in April, when a distraught Kirchherr met them at the airport with news of Sutcliffe's death the previous day from what was later determined as a brain haemorrhage.[37]
+
+Epstein began negotiations with record labels for a recording contract. To secure a UK record contract, Epstein negotiated an early end to the band's contract with Polydor, in exchange for more recordings backing Tony Sheridan.[38] After a New Year's Day audition, Decca Records rejected the band with the comment "Guitar groups are on the way out, Mr. Epstein."[39] However, three months later, producer George Martin signed the Beatles to EMI's Parlophone label.[37]
+
+Martin's first recording session with the Beatles took place at EMI's Abbey Road Studios in London on 6 June 1962.[40] Martin immediately complained to Epstein about Best's poor drumming and suggested they use a session drummer in his place.[41] Already contemplating Best's dismissal,[42] the Beatles replaced him in mid-August with Ringo Starr, who left Rory Storm and the Hurricanes to join them.[40] A 4 September session at EMI yielded a recording of "Love Me Do" featuring Starr on drums, but a dissatisfied Martin hired drummer Andy White for the band's third session a week later, which produced recordings of "Love Me Do", "Please Please Me" and "P.S. I Love You".[40]
+
+Martin initially selected the Starr version of "Love Me Do" for the band's first single, though subsequent re-pressings featured the White version, with Starr on tambourine.[40] Released in early October, "Love Me Do" peaked at number seventeen on the Record Retailer chart.[43] Their television debut came later that month with a live performance on the regional news programme People and Places.[44] After Martin suggested rerecording "Please Please Me" at a faster tempo,[45] a studio session in late November yielded that recording,[46] of which Martin accurately predicted, "You've just made your first No. 1."[47]
+
+In December 1962, the Beatles concluded their fifth and final Hamburg residency.[48] By 1963, they had agreed that all four band members would contribute vocals to their albums – including Starr, despite his restricted vocal range, to validate his standing in the group.[49] Lennon and McCartney had established a songwriting partnership, and as the band's success grew, their dominant collaboration limited Harrison's opportunities as a lead vocalist.[50] Epstein, to maximise the Beatles' commercial potential, encouraged them to adopt a professional approach to performing.[51] Lennon recalled him saying, "Look, if you really want to get in these bigger places, you're going to have to change – stop eating on stage, stop swearing, stop smoking ...."[39] Lennon said: "We used to dress how we liked, on and off stage. He'd tell us that jeans were not particularly smart and could we possibly manage to wear proper trousers, but he didn't want us suddenly looking square. He'd let us have our own sense of individuality."[39]
+
+On 11 February 1963, the Beatles recorded ten songs during a single studio session for their debut LP, Please Please Me. The album was supplemented by the four tracks already released on their first two singles. Martin originally considered recording the Beatles' debut LP live at The Cavern Club, but after deciding that the building's acoustics were inadequate, he elected to simulate a "live" album with minimal production in "a single marathon session at Abbey Road".[53] After the moderate success of "Love Me Do", the single "Please Please Me" met with a more emphatic reception. Released in January 1963, two months ahead of the album of the same name, the song reached number one on every UK chart except Record Retailer, where it peaked at number two.[54]
+
+Recalling how the Beatles "rushed to deliver a debut album, bashing out Please Please Me in a day", AllMusic's Stephen Thomas Erlewine comments, "Decades after its release, the album still sounds fresh, precisely because of its intense origins."[55] Lennon said little thought went into composition at the time; he and McCartney were "just writing songs à la Everly Brothers, à la Buddy Holly, pop songs with no more thought of them than that – to create a sound. And the words were almost irrelevant."[56]
+
+Released in March 1963, the album initiated a run during which eleven of their twelve studio albums released in the United Kingdom through to 1970 reached number one.[59] The band's third single, "From Me to You", came out in April and was also a chart-topping hit, starting an almost unbroken string of seventeen British number-one singles for the Beatles, including all but one of the eighteen they released over the next six years.[60] Issued in August, the band's fourth single, "She Loves You", achieved the fastest sales of any record in the UK up to that time, selling three-quarters of a million copies in under four weeks.[61] It became their first single to sell a million copies, and remained the biggest-selling record in the UK until 1978.[62][nb 1]
+
+Their commercial success brought increased media exposure, to which the Beatles responded with an irreverent and comical attitude that defied the expectations of pop musicians at the time, inspiring even more interest.[63] The band toured the UK three times in the first half of the year: a four-week tour that began in February, the Beatles' first nationwide, preceded three-week tours in March and May–June.[64] As their popularity spread, a frenzied adulation of the group took hold. Greeted with riotous enthusiasm by screaming fans, the press dubbed the phenomenon "Beatlemania".[65] Although not billed as tour leaders, the Beatles overshadowed American acts Tommy Roe and Chris Montez during the February engagements and assumed top billing "by audience demand", something no British act had previously accomplished while touring with artists from the US.[66] A similar situation arose during their May–June tour with Roy Orbison.[67]
+
+In late October, the Beatles began a five-day tour of Sweden, their first time abroad since the final Hamburg engagement of December 1962.[69] On their return to the UK on 31 October, several hundred screaming fans greeted them in heavy rain at Heathrow Airport. Around 50 to 100 journalists and photographers, as well as representatives from the BBC, also joined the airport reception, the first of more than 100 such events.[70] The next day, the band began its fourth tour of Britain within nine months, this one scheduled for six weeks.[71] In mid-November, as Beatlemania intensified, police resorted to using high-pressure water hoses to control the crowd before a concert in Plymouth.[72]
+
+Please Please Me maintained the top position on the Record Retailer chart for 30 weeks, only to be displaced by its follow-up, With the Beatles,[73] which EMI released on 22 November to record advance orders of 270,000 copies. The LP topped a half-million albums sold in one week.[74] Recorded between July and October, With the Beatles made better use of studio production techniques than its predecessor.[75] It held the top spot for 21 weeks with a chart life of 40 weeks.[76] Erlewine described the LP as "a sequel of the highest order – one that betters the original".[77]
+
+In a reversal of then standard practice, EMI released the album ahead of the impending single "I Want to Hold Your Hand", with the song excluded to maximise the single's sales.[78] The album caught the attention of music critic William Mann of The Times, who suggested that Lennon and McCartney were "the outstanding English composers of 1963".[75] The newspaper published a series of articles in which Mann offered detailed analyses of the music, lending it respectability.[79] With the Beatles became the second album in UK chart history to sell a million copies, a figure previously reached only by the 1958 South Pacific soundtrack.[80] When writing the sleeve notes for the album, the band's press officer, Tony Barrow, used the superlative the "fabulous foursome", which the media widely adopted as "the Fab Four".[81]
+
+EMI's American subsidiary, Capitol Records, hindered the Beatles' releases in the United States for more than a year by initially declining to issue their music, including their first three singles. Concurrent negotiations with the independent US label Vee-Jay led to the release of some of the songs in 1963, but not all.[82] Vee-Jay finished preparation for the album Introducing... The Beatles, culled from most of the songs of Parlophone's Please Please Me, but a management shake-up led to the album not being released.[nb 2] Then when it surfaced that the label did not report royalties on their sales, the licence Vee-Jay signed with EMI was voided.[84] A new licence was granted to the Swan label for the single "She Loves You". The record received some airplay in the Tidewater area of Virginia by Gene Loving of radio station WGH and was featured on the "Rate-a-Record" segment of American Bandstand, but it failed to catch on nationally.[85]
+
+Epstein arranged for a $40,000 US marketing campaign. American chart success began after disc jockey Carroll James of AM radio station WWDC, in Washington, DC, obtained a copy of the British single "I Want to Hold Your Hand" in mid-December 1963 and began playing it on-air.[86] Taped copies of the song soon circulated among other radio stations throughout the US. This caused an increase in demand, leading Capitol to bring forward the release of "I Want to Hold Your Hand" by three weeks.[87] Issued on 26 December, with the band's previously scheduled debut there just weeks away, "I Want to Hold Your Hand" sold a million copies, becoming a number-one hit in the US by mid-January.[88] In its wake, Vee-Jay released Introducing... The Beatles[89] to go along with Capitol's debut album, Meet the Beatles!, while Swan reactivated production of "She Loves You".[90]
+
+On 7 February 1964, the Beatles left the UK with an estimated 4,000 fans gathered at Heathrow, waving and screaming as the aircraft took off.[91] Upon landing at New York's John F. Kennedy Airport, an uproarious crowd estimated at 3,000 greeted them.[92] They gave their first live US television performance two days later on The Ed Sullivan Show, watched by approximately 73 million viewers in over 23 million households,[93] or 34 percent of the American population. Biographer Jonathan Gould writes that, according to the Nielsen rating service, it was "the largest audience that had ever been recorded for an American television program".[94] The next morning, the Beatles awoke to a largely negative critical consensus in the US,[95] but a day later at their first US concert, Beatlemania erupted at the Washington Coliseum.[96] Back in New York the following day, the Beatles met with another strong reception during two shows at Carnegie Hall.[93] The band flew to Florida, where they appeared on the weekly Ed Sullivan Show a second time, before another 70 million viewers, before returning to the UK on 22 February.[97]
+
+The Beatles' first visit to the US took place when the nation were still mourning the assassination of President John F. Kennedy the previous November.[98] Commentators often suggest that for many, particularly the young, the Beatles' performances reignited the sense of excitement and possibility that momentarily faded in the wake of the assassination, and helped make way for the revolutionary social changes to come in the decade.[99] Their hairstyle, unusually long for the era and mocked by many adults,[14] became an emblem of rebellion to the burgeoning youth culture.[100]
+
+The group's popularity generated unprecedented interest in British music, and many other UK acts subsequently made their American debuts, successfully touring over the next three years in what was termed the British Invasion.[101] The Beatles' success in the US opened the door for a successive string of British beat groups and pop acts such as the Dave Clark Five, the Animals, Petula Clark, the Kinks, and the Rolling Stones to achieve success in America.[102] During the week of 4 April 1964, the Beatles held twelve positions on the Billboard Hot 100 singles chart, including the top five.[103][nb 3]
+
+Capitol Records' lack of interest throughout 1963 did not go unnoticed, and a competitor, United Artists Records, encouraged their film division to offer the Beatles a three-motion-picture deal, primarily for the commercial potential of the soundtracks in the US.[105] Directed by Richard Lester, A Hard Day's Night involved the band for six weeks in March–April 1964 as they played themselves in a musical comedy.[106] The film premiered in London and New York in July and August, respectively, and was an international success, with some critics drawing a comparison with the Marx Brothers.[107]
+
+United Artists released a full soundtrack album for the North American market, combining Beatles songs and Martin's orchestral score; elsewhere, the group's third studio LP, A Hard Day's Night, contained songs from the film on side one and other new recordings on side two.[108] According to Erlewine, the album saw them "truly coming into their own as a band. All of the disparate influences on their first two albums coalesced into a bright, joyous, original sound, filled with ringing guitars and irresistible melodies."[109] That "ringing guitar" sound was primarily the product of Harrison's 12-string electric Rickenbacker, a prototype given to him by the manufacturer, which made its debut on the record.[110][nb 4]
+
+Touring internationally in June and July, the Beatles staged 37 shows over 27 days in Denmark, the Netherlands, Hong Kong, Australia and New Zealand.[111][nb 5] In August and September they returned to the US, with a 30-concert tour of 23 cities.[113] Generating intense interest once again, the month-long tour attracted between 10,000 and 20,000 fans to each 30-minute performance in cities from San Francisco to New York.[113]
+
+In August, journalist Al Aronowitz arranged for the Beatles to meet Bob Dylan.[114] Visiting the band in their New York hotel suite, Dylan introduced them to cannabis.[115] Gould points out the musical and cultural significance of this meeting, before which the musicians' respective fanbases were "perceived as inhabiting two separate subcultural worlds": Dylan's audience of "college kids with artistic or intellectual leanings, a dawning political and social idealism, and a mildly bohemian style" contrasted with their fans, "veritable 'teenyboppers' – kids in high school or grade school whose lives were totally wrapped up in the commercialised popular culture of television, radio, pop records, fan magazines, and teen fashion. To many of Dylan's followers in the folk music scene, the Beatles were seen as idolaters, not idealists."[116] Within six months of the meeting, according to Gould, "Lennon would be making records on which he openly imitated Dylan's nasal drone, brittle strum, and introspective vocal persona"; and six months after that, Dylan began performing with a backing band and electric instrumentation, and "dressed in the height of Mod fashion".[117] As a result, Gould continues, the traditional division between folk and rock enthusiasts "nearly evaporated", as the Beatles' fans began to mature in their outlook and Dylan's audience embraced the new, youth-driven pop culture.[117]
+
+During the 1964 US tour, the group were confronted with racial segregation in the country at the time.[118][119] When informed that the venue for their 11 September concert, the Gator Bowl in Jacksonville, Florida, was segregated, the Beatles said they would refuse to perform unless the audience was integrated.[120][118][119] Lennon stated: "We never play to segregated audiences and we aren't going to start now ... I'd sooner lose our appearance money."[118] City officials relented and agreed to allow an integrated show.[118] The group also cancelled their reservations at the whites-only Hotel George Washington in Jacksonville.[119] For their subsequent US tours in 1965 and 1966, the Beatles included clauses in contracts stipulating that shows be integrated.[119][121]
+
+According to Gould, Beatles for Sale, the Beatles' fourth studio LP, evidenced a growing conflict between the commercial pressures of their global success and their creative ambitions.[122] They had intended the album, recorded between August and October 1964,[123] to continue the format established by A Hard Day's Night which, unlike their first two LPs, contained only original songs.[122] They had nearly exhausted their backlog of songs on the previous album, however, and given the challenges constant international touring posed to their songwriting efforts, Lennon admitted, "Material's becoming a hell of a problem".[124] As a result, six covers from their extensive repertoire were chosen to complete the album. Released in early December, its eight original compositions stood out, demonstrating the growing maturity of the Lennon–McCartney songwriting partnership.[122]
+
+In early 1965, following a dinner with Lennon, Harrison and their wives, Harrison's dentist, John Riley, secretly added LSD to their coffee.[125] Lennon described the experience: "It was just terrifying, but it was fantastic. I was pretty stunned for a month or two."[126] He and Harrison subsequently became regular users of the drug, joined by Starr on at least one occasion. Harrison's use of psychedelic drugs encouraged his path to meditation and Hinduism. He commented: "For me, it was like a flash. The first time I had acid, it just opened up something in my head that was inside of me, and I realized a lot of things. I didn't learn them because I already knew them, but that happened to be the key that opened the door to reveal them. From the moment I had that, I wanted to have it all the time – these thoughts about the yogis and the Himalayas, and Ravi's music."[127][128] McCartney was initially reluctant to try it, but eventually did so in late 1966.[129] He became the first Beatle to discuss LSD publicly, declaring in a magazine interview that "it opened my eyes" and "made me a better, more honest, more tolerant member of society".[130]
+
+Controversy erupted in June 1965 when Queen Elizabeth II appointed all four Beatles Members of the Order of the British Empire (MBE) after Prime Minister Harold Wilson nominated them for the award.[131] In protest – the honour was at that time primarily bestowed upon military veterans and civic leaders – some conservative MBE recipients returned their insignia.[132]
+
+In July, the Beatles' second film, Help!, was released, again directed by Lester. Described as "mainly a relentless spoof of Bond",[133] it inspired a mixed response among both reviewers and the band. McCartney said: "Help! was great but it wasn't our film – we were sort of guest stars. It was fun, but basically, as an idea for a film, it was a bit wrong."[134] The soundtrack was dominated by Lennon, who wrote and sang lead on most of its songs, including the two singles: "Help!" and "Ticket to Ride".[135] The accompanying Help! album, the group's fifth studio LP, mirrored A Hard Day's Night by featuring soundtrack songs on side one and additional songs from the same sessions on side two.[136] The LP contained all original material save for two covers, "Act Naturally" and "Dizzy Miss Lizzy"; they were the last covers the band would include on an album, except for Let It Be's brief rendition of the traditional Liverpool folk song "Maggie Mae".[137] The band expanded their use of vocal overdubs on Help! and incorporated classical instruments into some arrangements, including a string quartet on the pop ballad "Yesterday".[138] Composed by and sung by McCartney – none of the other Beatles perform on the recording[139] – "Yesterday" inspired the most cover versions of any song ever written.[140] With Help!, the Beatles became the first rock group to be nominated for a Grammy Award for Album of the Year.[141]
+
+The group's third US tour opened with a performance before a world-record crowd of 55,600 at New York's Shea Stadium on 15 August 1965 – "perhaps the most famous of all Beatles' concerts", in Lewisohn's description.[142] A further nine successful concerts followed in other American cities. At a show in Atlanta, the Beatles gave one of the first live performances ever to make use of a foldback system of on-stage monitor speakers.[143] Towards the end of the tour, they met with Elvis Presley, a foundational musical influence on the band, who invited them to his home in Beverly Hills.[144][145] September saw the launch of an American Saturday-morning cartoon series, The Beatles, that echoed A Hard Day's Night's slapstick antics over its two-year original run.[146] The series was a historical milestone as the first weekly television series to feature animated versions of real, living people.[147]
+
+In mid-October 1965, the Beatles entered the recording studio; for the first time when making an album, they had an extended period without other major commitments.[148] Until this time, according to George Martin, "we had been making albums rather like a collection of singles. Now we were really beginning to think about albums as a bit of art on their own."[149] Released in December, Rubber Soul was hailed by critics as a major step forward in the maturity and complexity of the band's music.[150] Their thematic reach was beginning to expand as they embraced deeper aspects of romance and philosophy.[151] NEMS executive Peter Brown attributed the new musical direction to "the Beatles' now habitual use of marijuana",[152] an assertion confirmed by the band – Lennon referred to it as "the pot album",[153] and Starr said: "Grass was really influential in a lot of our changes, especially with the writers. And because they were writing different material, we were playing differently."[153] After Help!'s foray into the world of classical music with flutes and strings, Harrison's introduction of a sitar on "Norwegian Wood (This Bird Has Flown)" marked a further progression outside the traditional boundaries of popular music. As their lyrics grew more artful, fans began to study them for deeper meaning. Of "Norwegian Wood" Lennon commented: "I was trying to be sophisticated in writing about an affair ... but in such a smokescreen way that you couldn't tell."[154]
+
+While many of Rubber Soul's prominent songs were the product of Lennon and McCartney's collaborative songwriting,[155] it also featured distinct compositions from each,[156] though they continued to share official credit. The song "In My Life", of which each later claimed lead authorship, is considered a highlight of the entire Lennon–McCartney catalogue.[157] Harrison called Rubber Soul his "favourite album"[153] and Starr referred to it as "the departure record".[158] McCartney has said, "We'd had our cute period, and now it was time to expand."[159] However, recording engineer Norman Smith later stated that the studio sessions revealed signs of growing conflict within the group – "the clash between John and Paul was becoming obvious", he wrote, and "as far as Paul was concerned, George could do no right".[160] In 2003, Rolling Stone ranked Rubber Soul fifth among "The 500 Greatest Albums of All Time",[161] and AllMusic's Richie Unterberger describes it as "one of the classic folk-rock records".[162]
+
+Capitol Records, from December 1963 when it began issuing Beatles recordings for the US market, exercised complete control over format,[82] compiling distinct US albums from the band's recordings and issuing songs of their choosing as singles.[163][nb 6] In June 1966, Yesterday and Today, one of Capitol's compilation albums, caused an uproar with its cover, which portrayed the grinning Beatles dressed in butcher's overalls, accompanied by raw meat and mutilated plastic baby dolls. According to Beatles biographer Bill Harry, it has been incorrectly suggested that this was meant as a satirical response to the way Capitol had "butchered" the US versions of the band's albums.[165] Thousands of copies of the LP had a new cover pasted over the original; an unpeeled "first-state" copy fetched $10,500 at a December 2005 auction.[166] In England, meanwhile, Harrison met sitar maestro Ravi Shankar, who agreed to train him on the instrument.[167]
+
+During a tour of the Philippines the month after the Yesterday and Today furore, the Beatles unintentionally snubbed the nation's first lady, Imelda Marcos, who had expected them to attend a breakfast reception at the Presidential Palace.[168] When presented with the invitation, Epstein politely declined on the band members' behalf, as it had never been his policy to accept such official invitations.[169] They soon found that the Marcos regime was unaccustomed to taking no for an answer. The resulting riots endangered the group and they escaped the country with difficulty.[170] Immediately afterwards, the band members visited India for the first time.[171]
+
+– John Lennon, 1966[172]
+
+Almost as soon as they returned home, the Beatles faced a fierce backlash from US religious and social conservatives (as well as the Ku Klux Klan) over a comment Lennon had made in a March interview with British reporter Maureen Cleave.[173] "Christianity will go", Lennon had said. "It will vanish and shrink. I needn't argue about that; I'm right and I will be proved right ... Jesus was alright but his disciples were thick and ordinary. It's them twisting it that ruins it for me."[174] His comments went virtually unnoticed in England, but when US teenage fan magazine Datebook printed them five months later, it sparked a controversy with Christians in America's conservative Bible Belt region.[173] The Vatican issued a protest, and bans on Beatles' records were imposed by Spanish and Dutch stations and South Africa's national broadcasting service.[175] Epstein accused Datebook of having taken Lennon's words out of context. At a press conference Lennon pointed out, "If I'd said television was more popular than Jesus, I might have got away with it."[176] He claimed that he was referring to how other people viewed their success, but at the prompting of reporters, he concluded: "If you want me to apologise, if that will make you happy, then okay, I'm sorry."[176]
+
+Released in August, a week before the Beatles' final tour, Revolver marked another artistic step forward for the group.[177] The album featured sophisticated songwriting, studio experimentation, and a greatly expanded repertoire of musical styles, ranging from innovative classical string arrangements to psychedelic rock.[177] Abandoning the customary group photograph, its Aubrey Beardsley-inspired cover – designed by Klaus Voormann, a friend of the band since their Hamburg days – was a monochrome collage and line drawing caricature of the group.[177] The album was preceded by the single "Paperback Writer", backed by "Rain".[178] Short promotional films were made for both songs; described by cultural historian Saul Austerlitz as "among the first true music videos",[179] they aired on The Ed Sullivan Show and Top of the Pops in June.[180]
+
+Among the experimental songs that Revolver featured was "Tomorrow Never Knows", the lyrics for which Lennon drew from Timothy Leary's The Psychedelic Experience: A Manual Based on the Tibetan Book of the Dead. Its creation involved eight tape decks distributed about the EMI building, each staffed by an engineer or band member, who randomly varied the movement of a tape loop while Martin created a composite recording by sampling the incoming data.[181] McCartney's "Eleanor Rigby" made prominent use of a string octet; Gould describes it as "a true hybrid, conforming to no recognisable style or genre of song".[182] Harrison was developing as a songwriter, and three of his compositions earned a place on the record.[183] In 2003, Rolling Stone ranked Revolver as the third greatest album of all time.[161]
+
+As preparations were made for a tour of the US, the Beatles knew that their music would hardly be heard. Having originally used Vox AC30 amplifiers, they later acquired more powerful 100-watt amplifiers, specially designed by Vox for them as they moved into larger venues in 1964, but these were still inadequate. Struggling to compete with the volume of sound generated by screaming fans, the band had grown increasingly bored with the routine of performing live.[184] Recognising that their shows were no longer about the music, they decided to make the August tour their last.[185]
+
+The band performed none of their new songs on the tour.[186] In Chris Ingham's description, they were very much "studio creations ... and there was no way a four-piece rock 'n' roll group could do them justice, particularly through the desensitising wall of the fans' screams. 'Live Beatles' and 'Studio Beatles' had become entirely different beasts."[187] The band's concert at San Francisco's Candlestick Park on 29 August was their last commercial concert.[188] It marked the end of four years dominated by almost nonstop touring that included over 1,400 concert appearances internationally.[189]
+
+Freed from the burden of touring, the Beatles embraced an increasingly experimental approach as they recorded Sgt. Pepper's Lonely Hearts Club Band, beginning in late November 1966.[191] According to engineer Geoff Emerick, the album's recording took over 700 hours.[192] He recalled the band's insistence "that everything on Sgt. Pepper had to be different. We had microphones right down in the bells of brass instruments and headphones turned into microphones attached to violins. We used giant primitive oscillators to vary the speed of instruments and vocals and we had tapes chopped to pieces and stuck together upside down and the wrong way around."[193] Parts of "A Day in the Life" featured a 40-piece orchestra.[193] The sessions initially yielded the non-album double A-side single "Strawberry Fields Forever"/"Penny Lane" in February 1967;[194] the Sgt. Pepper LP followed with a rush-release in May.[195] The musical complexity of the records, created using relatively primitive four-track recording technology, astounded contemporary artists.[190]  Among music critics, acclaim for the album was virtually universal.[196] Gould writes:
+
+The overwhelming consensus is that the Beatles had created a popular masterpiece: a rich, sustained, and overflowing work of collaborative genius whose bold ambition and startling originality dramatically enlarged the possibilities and raised the expectations of what the experience of listening to popular music on record could be. On the basis of this perception, Sgt. Pepper became the catalyst for an explosion of mass enthusiasm for album-formatted rock that would revolutionise both the aesthetics and the economics of the record business in ways that far outstripped the earlier pop explosions triggered by the Elvis phenomenon of 1956 and the Beatlemania phenomenon of 1963.[197]
+
+In the wake of Sgt. Pepper, the underground and mainstream press widely publicised the Beatles as leaders of youth culture, as well as "lifestyle revolutionaries".[3] The album was the first major pop/rock LP to include its complete lyrics, which appeared on the back cover.[198][199] Those lyrics were the subject of critical analysis; for instance, in late 1967 the album was the subject of a scholarly inquiry by American literary critic and professor of English Richard Poirier, who observed that his students were "listening to the group's music with a degree of engagement that he, as a teacher of literature, could only envy".[200][nb 7] The elaborate cover also attracted considerable interest and study.[201] A collage designed by pop artists Peter Blake and Jann Haworth, it depicted the group as the fictional band referred to in the album's title track[202] standing in front of a crowd of famous people.[203] The heavy moustaches worn by the group reflected the growing influence of hippie style,[204] while cultural historian Jonathan Harris describes their "brightly coloured parodies of military uniforms" as a knowingly "anti-authoritarian and anti-establishment" display.[205]
+
+Sgt. Pepper topped the UK charts for 23 consecutive weeks, with a further four weeks at number one in the period through to February 1968.[206] With 2.5 million copies sold within three months of its release,[207] Sgt. Pepper's initial commercial success exceeded that of all previous Beatles albums.[208] It sustained its immense popularity into the 21st century while breaking numerous sales records.[209]  In 2003, Rolling Stone ranked Sgt. Pepper foremost on its list of the greatest albums of all time.[161]
+
+Two Beatles film projects were conceived within weeks of completing Sgt. Pepper: Magical Mystery Tour, a one-hour television film, and Yellow Submarine, an animated feature-length film produced by United Artists.[210] The group began recording music for the former in late April 1967, but the project then lay dormant as they focused on recording songs for the latter.[211] On 25 June, the Beatles performed their forthcoming single "All You Need Is Love" to an estimated 350 million viewers on Our World, the first live global television link.[212] Released a week later, during the Summer of Love, the song was adopted as a flower power anthem.[213] The Beatles' use of psychedelic drugs was at its height during that summer.[214] In July and August, the group pursued interests related to similar utopian-based ideology, including a week-long investigation into the possibility of starting an island-based commune off the coast of Greece.[215]
+
+On 24 August, the group were introduced to Maharishi Mahesh Yogi in London. The next day, they travelled to Bangor for his Transcendental Meditation retreat. On 27 August, their manager's assistant, Peter Brown, phoned to inform them that Epstein had died.[216] The coroner ruled the death an accidental carbitol overdose, although it was widely rumoured to be a suicide.[217][nb 8] His death left the group disoriented and fearful about the future.[219] Lennon recalled: "We collapsed. I knew that we were in trouble then. I didn't really have any misconceptions about our ability to do anything other than play music, and I was scared. I thought, 'We've fuckin' had it now.'"[220] Harrison's then-wife Pattie Boyd remembered that "Paul and George were in complete shock. I don't think it could have been worse if they had heard that their own fathers had dropped dead."[221] During a band meeting in September, McCartney recommended that the band proceed with Magical Mystery Tour.[211]
+
+The Magical Mystery Tour soundtrack was released in the UK as a six-track double extended play (EP) in early December 1967.[82][222] It was the first example of a double EP in the UK.[223][224] The record carried on the psychedelic vein of Sgt. Pepper,[225] however, in line with the band's wishes, the packaging reinforced the idea that the release was a film soundtrack rather than a follow-up to Sgt. Pepper.[222]  In the US, the soundtrack appeared as an identically titled LP that also included five tracks from the band's recent singles.[104] In its first three weeks, the album set a record for the highest initial sales of any Capitol LP, and it is the only Capitol compilation later to be adopted in the band's official canon of studio albums.[226]
+
+Magical Mystery Tour first aired on Boxing Day to an audience of approximately 15 million.[227] Largely directed by McCartney, the film was the band's first critical failure in the UK.[228] It was dismissed as "blatant rubbish" by the Daily Express; the Daily Mail called it "a colossal conceit"; and The Guardian labelled the film "a kind of fantasy morality play about the grossness and warmth and stupidity of the audience".[229] Gould describes it as "a great deal of raw footage showing a group of people getting on, getting off, and riding on a bus".[229] Although the viewership figures were respectable, its slating in the press led US television networks to lose interest in broadcasting the film.[230]
+
+The group were less involved with Yellow Submarine, which only featured the band appearing as themselves for a short live-action segment.[231] Premiering in July 1968, the film featured cartoon versions of the band members and a soundtrack with eleven of their songs, including four unreleased studio recordings that made their debut in the film.[232] Critics praised the film for its music, humour and innovative visual style.[233] A soundtrack LP was issued seven months later; it contained those four new songs, the title track (already issued on Revolver), "All You Need Is Love" (already issued as a single and on the US Magical Mystery Tour LP) and seven instrumental pieces composed by Martin.[234]
+
+In February 1968, the Beatles travelled to Maharishi Mahesh Yogi's ashram in Rishikesh, India, to take part in a three-month meditation "Guide Course". Their time in India marked one of the band's most prolific periods, yielding numerous songs, including a majority of those on their next album.[235] However, Starr left after only ten days, unable to stomach the food, and McCartney eventually grew bored and departed a month later.[236] For Lennon and Harrison, creativity turned to question when an electronics technician known as Magic Alex suggested that the Maharishi was attempting to manipulate them.[237] When he alleged that the Maharishi had made sexual advances to women attendees, a persuaded Lennon left abruptly just two months into the course, bringing an unconvinced Harrison and the remainder of the group's entourage with him.[236] In anger, Lennon wrote a scathing song titled "Maharishi", renamed "Sexy Sadie" to avoid potential legal issues. McCartney said, "We made a mistake. We thought there was more to him than there was."[237]
+
+In May, Lennon and McCartney traveled to New York for the public unveiling of the Beatles' new business venture, Apple Corps.[238] It was initially formed several months earlier as part of a plan to create a tax-effective business structure, but the band then desired to extend the corporation to other pursuits, including record distribution, peace activism, and education.[239] McCartney described Apple as "rather like a Western communism".[240] The enterprise drained the group financially with a series of unsuccessful projects[241] handled largely by members of the Beatles' entourage, who were given their jobs regardless of talent and experience.[242] Among its numerous subsidiaries were Apple Electronics, established to foster technological innovations with Magic Alex at the head, and Apple Retailing, which opened the short-lived Apple Boutique in London.[243] Harrison later said, "Basically, it was chaos ... John and Paul got carried away with the idea and blew millions, and Ringo and I just had to go along with it."[240]
+
+From late May to mid-October 1968, the group recorded what became The Beatles, a double LP commonly known as "the White Album" for its virtually featureless cover.[245] During this time, relations between the members grew openly divisive.[246] Starr quit for two weeks, leaving his bandmates to record "Back in the U.S.S.R." and "Dear Prudence" as a trio.[247] Lennon had lost interest in collaborating with McCartney,[248] whose contribution "Ob-La-Di, Ob-La-Da" he scorned as "granny music shit".[249] Tensions were further aggravated by Lennon's romantic preoccupation with avant-garde artist Yoko Ono, whom he insisted on bringing to the sessions despite the group's well-established understanding that girlfriends were not allowed in the studio.[250] McCartney has recalled that the album "wasn't a pleasant one to make".[251] He and Lennon identified the sessions as the start of the band's break-up.[252][253]
+
+With the record, the band executed a wider range of musical styles[254] and broke with their recent tradition of incorporating several musical styles in one song by keeping each piece of music consistently faithful to a select genre.[255] During the sessions, the group upgraded to an eight-track tape console, which made it easier for them to layer tracks piecemeal, while the members often recorded independently of each other, affording the album a reputation as a collection of solo recordings rather than a unified group effort.[256] Describing the double album, Lennon later said: "Every track is an individual track; there isn't any Beatle music on it. [It's] John and the band, Paul and the band, George and the band."[257] The sessions also produced the Beatles' longest song yet, "Hey Jude", released in August as a non-album single with "Revolution".[258]
+
+Issued in November, the White Album was the band's first Apple Records album release, although EMI continued to own their recordings.[259] The record attracted more than 2 million advance orders, selling nearly 4 million copies in the US in little over a month, and its tracks dominated the playlists of American radio stations.[260] Its lyric content was the focus of much analysis by the counterculture.[261] Despite its popularity, reviewers were largely confused by the album's content, and it failed to inspire the level of critical writing that Sgt. Pepper had.[260] General critical opinion eventually turned in favour of the White Album, and in 2003, Rolling Stone ranked it as the tenth greatest album of all time.[161]
+
+Although Let It Be was the Beatles' final album release, it was largely recorded before Abbey Road. The project's impetus came from an idea Martin attributes to McCartney, who suggested they "record an album of new material and rehearse it, then perform it before a live audience for the very first time – on record and on film".[262] Originally intended for a one-hour television programme to be called Beatles at Work, in the event much of the album's content came from studio work beginning in January 1969, many hours of which were captured on film by director Michael Lindsay-Hogg.[262][263] Martin said that the project was "not at all a happy recording experience. It was a time when relations between the Beatles were at their lowest ebb."[262] Lennon described the largely impromptu sessions as "hell ... the most miserable ... on Earth", and Harrison, "the low of all-time".[264] Irritated by McCartney and Lennon, Harrison walked out for five days. Upon returning, he threatened to leave the band unless they "abandon[ed] all talk of live performance" and instead focused on finishing a new album, initially titled Get Back, using songs recorded for the TV special.[265] He also demanded they cease work at Twickenham Film Studios, where the sessions had begun, and relocate to the newly finished Apple Studio. His bandmates agreed, and it was decided to salvage the footage shot for the TV production for use in a feature film.[266]
+
+To alleviate tensions within the band and improve the quality of their live sound, Harrison invited keyboardist Billy Preston to participate in the last nine days of sessions.[267] Preston received label billing on the "Get Back" single – the only musician ever to receive that acknowledgment on an official Beatles release.[268] After the rehearsals, the band could not agree on a location to film a concert, rejecting several ideas, including a boat at sea, a lunatic asylum, the Tunisian desert, and the Colosseum.[262] Ultimately, what would be their final live performance was filmed on the rooftop of the Apple Corps building at 3 Savile Row, London, on 30 January 1969.[269] Five weeks later, engineer Glyn Johns, whom Lewisohn describes as Get Back's "uncredited producer", began work assembling an album, given "free rein" as the band "all but washed their hands of the entire project".[270]
+
+New strains developed between the band members regarding the appointment of a financial adviser, the need for which had become evident without Epstein to manage business affairs. Lennon, Harrison and Starr favoured Allen Klein, who had managed the Rolling Stones and Sam Cooke;[271] McCartney wanted Lee and John Eastman – father and brother, respectively, of Linda Eastman,[272] whom McCartney married on 12 March.[273] Agreement could not be reached, so both Klein and the Eastmans were temporarily appointed: Klein as the Beatles' business manager and the Eastmans as their lawyers.[274][275] Further conflict ensued, however, and financial opportunities were lost.[271] On 8 May, Klein was named sole manager of the band,[276] the Eastmans having previously been dismissed as the Beatles' lawyers. McCartney refused to sign the management contract with Klein, but he was out-voted by the other Beatles.[277]
+
+Martin stated that he was surprised when McCartney asked him to produce another album, as the Get Back sessions had been "a miserable experience" and he had "thought it was the end of the road for all of us".[278] The primary recording sessions for Abbey Road began on 2 July.[279] Lennon, who rejected Martin's proposed format of a "continuously moving piece of music", wanted his and McCartney's songs to occupy separate sides of the album.[280] The eventual format, with individually composed songs on the first side and the second consisting largely of a medley, was McCartney's suggested compromise.[280] Emerick noted that the replacement of the studio's valve mixing console with a transistorised one yielded a less punchy sound, leaving the group frustrated at the thinner tone and lack of impact and contributing to its "kinder, gentler" feel relative to their previous albums.[281]
+
+On 4 July, the first solo single by a Beatle was released: Lennon's "Give Peace a Chance", credited to the Plastic Ono Band. The completion and mixing of "I Want You (She's So Heavy)" on 20 August was the last occasion on which all four Beatles were together in the same studio.[282] On 8 September, while Starr was in hospital, the other band members met to discuss recording a new album. They considered a different approach to songwriting by ending the Lennon–McCartney pretense and having four compositions apiece from Lennon, McCartney and Harrison, with two from Starr and a lead single around Christmas.[283] On 20 September, Lennon announced his departure to the rest of the group but agreed to withhold a public announcement to avoid undermining sales of the forthcoming album.[284]
+
+Released on 26 September, Abbey Road sold four million copies within three months and topped the UK charts for a total of seventeen weeks.[285] Its second track, the ballad "Something", was issued as a single – the only Harrison composition that appeared as a Beatles A-side.[286] Abbey Road received mixed reviews, although the medley met with general acclaim.[285] Unterberger considers it "a fitting swan song for the group", containing "some of the greatest harmonies to be heard on any rock record".[287] Musicologist and author Ian MacDonald calls the album "erratic and often hollow", despite the "semblance of unity and coherence" offered by the medley.[288] Martin singled it out as his favourite Beatles album; Lennon said it was "competent" but had "no life in it".[281]
+
+For the still unfinished Get Back album, one last song, Harrison's "I Me Mine", was recorded on 3 January 1970. Lennon, in Denmark at the time, did not participate.[289] In March, rejecting the work Johns had done on the project, now retitled Let It Be, Klein gave the session tapes to American producer Phil Spector, who had recently produced Lennon's solo single "Instant Karma!"[290] In addition to remixing the material, Spector edited, spliced and overdubbed several of the recordings that had been intended as "live". McCartney was unhappy with the producer's approach and particularly dissatisfied with the lavish orchestration on "The Long and Winding Road", which involved a fourteen-voice choir and 36-piece instrumental ensemble.[291] McCartney's demands that the alterations to the song be reverted were ignored,[292] and he publicly announced his departure from the band on 10 April, a week before the release of his first, self-titled solo album.[291][293]
+
+On 8 May 1970, Let It Be was released. Its accompanying single, "The Long and Winding Road", was the Beatles' last; it was released in the US, but not in the UK.[178] The Let It Be documentary film followed later that month, and would win the 1970 Academy Award for Best Original Song Score.[294] Sunday Telegraph critic Penelope Gilliatt called it "a very bad film and a touching one ... about the breaking apart of this reassuring, geometrically perfect, once apparently ageless family of siblings".[295] Several reviewers stated that some of the performances in the film sounded better than their analogous album tracks.[296] Describing Let It Be as the "only Beatles album to occasion negative, even hostile reviews", Unterberger calls it "on the whole underrated"; he singles out "some good moments of straight hard rock in 'I've Got a Feeling' and 'Dig a Pony'", and praises "Let It Be", "Get Back", and "the folky 'Two of Us', with John and Paul harmonising together".[297]
+
+McCartney filed suit for the dissolution of the Beatles' contractual partnership on 31 December 1970.[298] Legal disputes continued long after their break-up, and the dissolution was not formalised until 29 December 1974,[299] when Lennon signed the paperwork terminating the partnership while on vacation with his family at Walt Disney World Resort in Florida.[300]
+
+Lennon, McCartney, Harrison and Starr all released solo albums in 1970. Their solo records sometimes involved one or more of the others;[301] Starr's Ringo (1973) was the only album to include compositions and performances by all four ex-Beatles, albeit on separate songs. With Starr's participation, Harrison staged the Concert for Bangladesh in New York City in August 1971.[302] Other than an unreleased jam session in 1974, later bootlegged as A Toot and a Snore in '74, Lennon and McCartney never recorded together again.[303]
+
+Two double-LP sets of the Beatles' greatest hits, compiled by Klein, 1962–1966 and 1967–1970, were released in 1973, at first under the Apple Records imprint.[304] Commonly known as the "Red Album" and "Blue Album", respectively, each has earned a Multi-Platinum certification in the US and a Platinum certification in the UK.[305][306] Between 1976 and 1982, EMI/Capitol released a wave of compilation albums without input from the ex-Beatles, starting with the double-disc compilation Rock 'n' Roll Music.[307] The only one to feature previously unreleased material was The Beatles at the Hollywood Bowl (1977); the first officially issued concert recordings by the group, it contained selections from two shows they played during their 1964 and 1965 US tours.[308][nb 9]
+
+The music and enduring fame of the Beatles were commercially exploited in various other ways, again often outside their creative control. In April 1974, the musical John, Paul, George, Ringo ... and Bert, written by Willy Russell and featuring singer Barbara Dickson, opened in London. It included, with permission from Northern Songs, eleven Lennon-McCartney compositions and one by Harrison, "Here Comes the Sun". Displeased with the production's use of his song, Harrison withdrew his permission to use it.[310] Later that year, the off-Broadway musical Sgt. Pepper's Lonely Hearts Club Band on the Road opened.[311] All This and World War II (1976) was an unorthodox nonfiction film that combined newsreel footage with covers of Beatles songs by performers ranging from Elton John and Keith Moon to the London Symphony Orchestra.[312] The Broadway musical Beatlemania, an unauthorised nostalgia revue, opened in early 1977 and proved popular, spinning off five separate touring productions.[313] In 1979, the band sued the producers, settling for several million dollars in damages.[313] Sgt. Pepper's Lonely Hearts Club Band (1978), a musical film starring the Bee Gees and Peter Frampton, was a commercial failure and an "artistic fiasco", according to Ingham.[314]
+
+Accompanying the wave of Beatles nostalgia and persistent reunion rumours in the US during the 1970s, several entrepreneurs made public offers to the Beatles for a reunion concert.[315] Promoter Bill Sargent first offered the Beatles $10 million for a reunion concert in 1974. He raised his offer to $30 million in January 1976 and then to $50 million the following month.[316][317] On 24 April 1976, during a broadcast of Saturday Night Live, producer Lorne Michaels offered the Beatles $3,000 to reunite on the show. Lennon and McCartney were watching the live broadcast at Lennon's apartment at the Dakota in New York, which was within driving distance of the NBC studio where the show was being broadcast. The former bandmates briefly entertained the idea of going to the studio and surprising Michaels by accepting his offer, but decided not to.[318]
+
+In December 1980, Lennon was shot and killed outside his New York City apartment. Harrison rewrote the lyrics of his song "All Those Years Ago" in Lennon's honour. With Starr on drums and McCartney and his wife, Linda, contributing backing vocals, the song was released as a single in May 1981.[319] McCartney's own tribute, "Here Today", appeared on his Tug of War album in April 1982.[320] In 1987, Harrison's Cloud Nine album included "When We Was Fab", a song about the Beatlemania era.[321]
+
+When the Beatles' studio albums were released on CD by EMI and Apple Corps in 1987, their catalogue was standardised throughout the world, establishing a canon of the twelve original studio LPs as issued in the UK plus the US LP version of Magical Mystery Tour.[322] All the remaining material from the singles and EPs that had not appeared on these thirteen studio albums was gathered on the two-volume compilation Past Masters (1988). Except for the Red and Blue albums, EMI deleted all its other Beatles compilations – including the Hollywood Bowl record – from its catalogue.[308]
+
+In 1988, the Beatles were inducted into the Rock and Roll Hall of Fame, their first year of eligibility. Harrison and Starr attended the ceremony with Lennon's widow, Yoko Ono, and his two sons, Julian and Sean.[323][324] McCartney declined to attend, citing unresolved "business differences" that would make him "feel like a complete hypocrite waving and smiling with them at a fake reunion".[324] The following year, EMI/Capitol settled a decade-long lawsuit filed by the band over royalties, clearing the way to commercially package previously unreleased material.[325][326]
+
+Live at the BBC, the first official release of unissued Beatles performances in seventeen years, appeared in 1994.[327] That same year McCartney, Harrison and Starr collaborated on the Anthology project. Anthology was the culmination of work begun in 1970, when Apple Corps director Neil Aspinall, their former road manager and personal assistant, had started to gather material for a documentary with the working title The Long and Winding Road.[328] Documenting their history in the band's own words, the Anthology project included the release of several unissued Beatles recordings. McCartney, Harrison and Starr also added new instrumental and vocal parts to songs recorded as demos by Lennon in the late 1970s.[329]
+
+During 1995–96, the project yielded a television miniseries, an eight-volume video set, and three two-CD/three-LP box sets featuring artwork by Klaus Voormann. Two songs based on Lennon demos, "Free as a Bird" and "Real Love", were issued as new Beatles singles. The releases were commercially successful and the television series was viewed by an estimated 400 million people.[330] In 1999, to coincide with the re-release of the 1968 film Yellow Submarine, an expanded soundtrack album, Yellow Submarine Songtrack, was issued.[331]
+
+The Beatles' 1, a compilation album of the band's British and American number-one hits, was released on 13 November 2000. It became the fastest-selling album of all time, with 3.6 million sold in its first week[332] and 13 million within a month.[333] It topped albums charts in at least 28 countries.[334] The compilation had sold 31 million copies globally by April 2009.[335]
+
+Harrison died from metastatic lung cancer in November 2001.[336][337][338] McCartney and Starr were among the musicians who performed at the Concert for George, organised by Eric Clapton and Harrison's widow, Olivia. The tribute event took place at the Royal Albert Hall on the first anniversary of Harrison's death.[339]
+
+In 2003, Let It Be... Naked, a reconceived version of the Let It Be album, with McCartney supervising production, was released. One of the main differences from the Spector-produced version was the omission of the original string arrangements.[340] It was a top ten hit in both Britain and America. The US album configurations from 1964 to 1965 were released as box sets in 2004 and 2006; The Capitol Albums, Volume 1 and Volume 2 included both stereo and mono versions based on the mixes that were prepared for vinyl at the time of the music's original American release.[341]
+
+As a soundtrack for Cirque du Soleil's Las Vegas Beatles stage revue, Love, George Martin and his son Giles remixed and blended 130 of the band's recordings to create what Martin called "a way of re-living the whole Beatles musical lifespan in a very condensed period".[342] The show premiered in June 2006, and the Love album was released that November.[343] In April 2009, Starr performed three songs with McCartney at a benefit concert held at New York's Radio City Music Hall and organised by McCartney.[344]
+
+On 9 September 2009, the Beatles' entire back catalogue was reissued following an extensive digital remastering process that lasted four years.[322] Stereo editions of all twelve original UK studio albums, along with Magical Mystery Tour and the Past Masters compilation, were released on compact disc both individually and as a box set.[345] A second collection, The Beatles in Mono, included remastered versions of every Beatles album released in true mono along with the original 1965 stereo mixes of Help! and Rubber Soul (both of which Martin had remixed for the 1987 editions).[346] The Beatles: Rock Band, a music video game in the Rock Band series, was issued on the same day.[347] In December 2009, the band's catalogue was officially released in FLAC and MP3 format in a limited edition of 30,000 USB flash drives.[348]
+
+Owing to a long-running royalty disagreement, the Beatles were among the last major artists to sign deals with online music services.[349] Residual disagreement emanating from Apple Corps' dispute with Apple, Inc., iTunes' owners, over the use of the name "Apple" was also partly responsible for the delay, although in 2008, McCartney stated that the main obstacle to making the Beatles' catalogue available online was that EMI "want[s] something we're not prepared to give them".[350] In 2010, the official canon of thirteen Beatles studio albums, Past Masters, and the "Red" and "Blue" greatest-hits albums were made available on iTunes.[351]
+
+In 2012, EMI's recorded music operations were sold to Universal Music Group. In order for Universal Music to acquire EMI, the European Union, for antitrust reasons, forced EMI to spin off assets including Parlophone. Universal was allowed to keep the Beatles' recorded music catalogue, managed by Capitol Records under its Capitol Music Group division.[352] The entire original Beatles album catalogue was also reissued on vinyl in 2012; available either individually or as a box set.[353]
+
+In 2013, a second volume of BBC recordings, titled On Air – Live at the BBC Volume 2, was released. That December saw the release of another 59 Beatles recordings on iTunes. The set, titled The Beatles Bootleg Recordings 1963, had the opportunity to gain a 70-year copyright extension conditional on the songs being published at least once before the end of 2013. Apple Records released the recordings on 17 December to prevent them from going into the public domain and had them taken down from iTunes later that same day. Fan reactions to the release were mixed, with one blogger saying "the hardcore Beatles collectors who are trying to obtain everything will already have these."[354][355]
+
+On 26 January 2014, McCartney and Starr performed together at the 56th Annual Grammy Awards, held at the Staples Center in Los Angeles.[356] The following day, The Night That Changed America: A Grammy Salute to The Beatles television special was taped in the Los Angeles Convention Center's West Hall. It aired on 9 February, the exact date of – and at the same time, and on the same network as – the original broadcast of the Beatles' first US television appearance on The Ed Sullivan Show, 50 years earlier. The special included performances of Beatles songs by current artists as well as by McCartney and Starr, archival footage, and interviews with the two surviving ex-Beatles carried out by David Letterman at the Ed Sullivan Theater.[357][358] In December 2015, the Beatles released their catalogue for streaming on various streaming music services including Spotify and Apple Music.[359]
+
+In September 2016, the documentary film The Beatles: Eight Days a Week was released. Directed by Ron Howard, it chronicled the Beatles' career during their touring years from 1962 to 1966, from their performances in Liverpool's the Cavern Club in 1961 to their final concert in San Francisco in 1966. The film was released theatrically on 15 September in the UK and the US, and started streaming on Hulu on 17 September. It received several awards and nominations, including for Best Documentary at the 70th British Academy Film Awards and the Outstanding Documentary or Nonfiction Special at the 69th Primetime Creative Arts Emmy Awards.[360] An expanded, remixed and remastered version of The Beatles at the Hollywood Bowl was released on 9 September, to coincide with the release of the film.[361][362]
+
+On 18 May 2017, Sirius XM Radio launched a 24/7 radio channel, The Beatles Channel. A week later, Sgt. Pepper's Lonely Hearts Club Band was reissued with new stereo mixes and unreleased material for the album's 50th anniversary.[363] Similar box sets were released for The Beatles in November 2018,[364] and Abbey Road in September 2019.[365] On the first week of October 2019, Abbey Road returned to number one on the UK Albums Chart. The Beatles broke their own record for the album with the longest gap between topping the charts as Abbey Road hit the top spot 50 years after its original release.[366]
+
+In August 2021, The Beatles: Get Back, a new documentary film directed by Peter Jackson utilising footage captured for what became the Let It Be film, will be released by Walt Disney Studios Motion Pictures in the US and Canada, with a global release to follow.[367]
+
+In Icons of Rock: An Encyclopedia of the Legends Who Changed Music Forever, Scott Schinder and Andy Schwartz describe the Beatles' musical evolution:
+
+In their initial incarnation as cheerful, wisecracking moptops, the Fab Four revolutionised the sound, style, and attitude of popular music and opened rock and roll's doors to a tidal wave of British rock acts. Their initial impact would have been enough to establish the Beatles as one of their era's most influential cultural forces, but they didn't stop there. Although their initial style was a highly original, irresistibly catchy synthesis of early American rock and roll and R&B, the Beatles spent the rest of the 1960s expanding rock's stylistic frontiers, consistently staking out new musical territory on each release. The band's increasingly sophisticated experimentation encompassed a variety of genres, including folk-rock, country, psychedelia, and baroque pop, without sacrificing the effortless mass appeal of their early work.[368]
+
+In The Beatles as Musicians, Walter Everett describes Lennon and McCartney's contrasting motivations and approaches to composition: "McCartney may be said to have constantly developed – as a means to entertain – a focused musical talent with an ear for counterpoint and other aspects of craft in the demonstration of a universally agreed-upon common language that he did much to enrich. Conversely, Lennon's mature music is best appreciated as the daring product of a largely unconscious, searching but undisciplined artistic sensibility."[369]
+
+Ian MacDonald describes McCartney as "a natural melodist – a creator of tunes capable of existing apart from their harmony". His melody lines are characterised as primarily "vertical", employing wide, consonant intervals which express his "extrovert energy and optimism". Conversely, Lennon's "sedentary, ironic personality" is reflected in a "horizontal" approach featuring minimal, dissonant intervals and repetitive melodies which rely on their harmonic accompaniment for interest: "Basically a realist, he instinctively kept his melodies close to the rhythms and cadences of speech, colouring his lyrics with bluesy tone and harmony rather than creating tunes that made striking shapes of their own."[370] MacDonald praises Harrison's lead guitar work for the role his "characterful lines and textural colourings" play in supporting Lennon and McCartney's parts, and describes Starr as "the father of modern pop/rock drumming".[371]
+
+The band's earliest influences include Elvis Presley, Carl Perkins, Little Richard and Chuck Berry.[372] During the Beatles' co-residency with Little Richard at the Star-Club in Hamburg, from April to May 1962, he advised them on the proper technique for performing his songs.[373] Of Presley, Lennon said, "Nothing really affected me until I heard Elvis. If there hadn't been Elvis, there would not have been the Beatles."[374] Other early influences include Buddy Holly, Eddie Cochran, Roy Orbison[375] and the Everly Brothers.[376]
+
+The Beatles continued to absorb influences long after their initial success, often finding new musical and lyrical avenues by listening to their contemporaries, including Bob Dylan, the Who, Frank Zappa, the Lovin' Spoonful, the Byrds and the Beach Boys, whose 1966 album Pet Sounds amazed and inspired McCartney.[377][378][379][380] Referring to the Beach Boys' creative leader, Martin later stated: "No one made a greater impact on the Beatles than Brian [Wilson]."[381] Ravi Shankar, with whom Harrison studied for six weeks in India in late 1966, had a significant effect on his musical development during the band's later years.[382]
+
+Originating as a skiffle group, the Beatles quickly embraced 1950s rock and roll and helped pioneer the Merseybeat genre,[383] and their repertoire ultimately expanded to include a broad variety of pop music.[384] Reflecting the range of styles they explored, Lennon said of Beatles for Sale, "You could call our new one a Beatles country-and-western LP",[385] while Gould credits Rubber Soul as "the instrument by which legions of folk-music enthusiasts were coaxed into the camp of pop".[386]
+
+Although the 1965 song "Yesterday" was not the first pop record to employ orchestral strings, it marked the group's first recorded use of classical music elements. Gould observes: "The more traditional sound of strings allowed for a fresh appreciation of their talent as composers by listeners who were otherwise allergic to the din of drums and electric guitars."[387] They continued to experiment with string arrangements to various effect; Sgt. Pepper's "She's Leaving Home", for instance, is "cast in the mold of a sentimental Victorian ballad", Gould writes, "its words and music filled with the clichés of musical melodrama".[388]
+
+The band's stylistic range expanded in another direction with their 1966 B-side "Rain", described by Martin Strong as "the first overtly psychedelic Beatles record".[389] Other psychedelic numbers followed, such as "Tomorrow Never Knows" (recorded before "Rain"), "Strawberry Fields Forever", "Lucy in the Sky with Diamonds" and "I Am the Walrus". The influence of Indian classical music was evident in Harrison's "The Inner Light", "Love You To" and "Within You Without You" – Gould describes the latter two as attempts "to replicate the raga form in miniature".[390]
+
+Innovation was the most striking feature of their creative evolution, according to music historian and pianist Michael Campbell: "'A Day in the Life' encapsulates the art and achievement of the Beatles as well as any single track can. It highlights key features of their music: the sound imagination, the persistence of tuneful melody, and the close coordination between words and music. It represents a new category of song – more sophisticated than pop ... and uniquely innovative. There literally had never before been a song – classical or vernacular – that had blended so many disparate elements so imaginatively."[391] Philosophy professor Bruce Ellis Benson agrees: "the Beatles ... give us a wonderful example of how such far-ranging influences as Celtic music, rhythm and blues, and country and western could be put together in a new way."[392]
+
+Author Dominic Pedler describes the way they crossed musical styles: "Far from moving sequentially from one genre to another (as is sometimes conveniently suggested) the group maintained in parallel their mastery of the traditional, catchy chart hit while simultaneously forging rock and dabbling with a wide range of peripheral influences from country to vaudeville. One of these threads was their take on folk music, which would form such essential groundwork for their later collisions with Indian music and philosophy."[393] As the personal relationships between the band members grew increasingly strained, their individual tastes became more apparent. The minimalistic cover artwork for the White Album contrasted with the complexity and diversity of its music, which encompassed Lennon's "Revolution 9" (whose musique concrète approach was influenced by Yoko Ono), Starr's country song "Don't Pass Me By", Harrison's rock ballad "While My Guitar Gently Weeps", and the "proto-metal roar" of McCartney's "Helter Skelter".[394]
+
+George Martin's close involvement in his role as producer made him one of the leading candidates for the informal title of the "fifth Beatle".[395] He applied his classical musical training in various ways, and functioned as "an informal music teacher" to the progressing songwriters, according to Gould.[396] Martin suggested to a sceptical McCartney that the arrangement of "Yesterday" should feature a string quartet accompaniment, thereby introducing the Beatles to a "hitherto unsuspected world of classical instrumental colour", in MacDonald's description.[397] Their creative development was also facilitated by Martin's willingness to experiment in response to their suggestions, such as adding "something baroque" to a particular recording.[398] In addition to scoring orchestral arrangements for recordings, Martin often performed on them, playing instruments including piano, organ and brass.[399]
+
+Collaborating with Lennon and McCartney required Martin to adapt to their different approaches to songwriting and recording. MacDonald comments, "while [he] worked more naturally with the conventionally articulate McCartney, the challenge of catering to Lennon's intuitive approach generally spurred him to his more original arrangements, of which 'Being for the Benefit of Mr. Kite!' is an outstanding example."[400] Martin said of the two composers' distinct songwriting styles and his stabilising influence:
+
+Compared with Paul's songs, all of which seemed to keep in some sort of touch with reality, John's had a psychedelic, almost mystical quality ... John's imagery is one of the best things about his work – 'tangerine trees', 'marmalade skies', 'cellophane flowers' ... I always saw him as an aural Salvador Dalí, rather than some drug-ridden record artist. On the other hand, I would be stupid to pretend that drugs didn't figure quite heavily in the Beatles' lives at that time ... they knew that I, in my schoolmasterly role, didn't approve ... Not only was I not into it myself, I couldn't see the need for it; and there's no doubt that, if I too had been on dope, Pepper would never have been the album it was. Perhaps it was the combination of dope and no dope that worked, who knows?[401]
+
+Harrison echoed Martin's description of his stabilising role: "I think we just grew through those years together, him as the straight man and us as the loonies; but he was always there for us to interpret our madness – we used to be slightly avant-garde on certain days of the week, and he would be there as the anchor person, to communicate that through the engineers and on to the tape."[402]
+
+Making innovative use of technology while expanding the possibilities of recorded music, the Beatles urged experimentation by Martin and his recording engineers. Seeking ways to put chance occurrences to creative use, accidental guitar feedback, a resonating glass bottle, a tape loaded the wrong way round so that it played backwards – any of these might be incorporated into their music.[403] Their desire to create new sounds on every new recording, combined with Martin's arranging abilities and the studio expertise of EMI staff engineers Norman Smith, Ken Townsend and Geoff Emerick, all contributed significantly to their records from Rubber Soul and, especially, Revolver onwards.[403]
+
+Along with innovative studio techniques such as sound effects, unconventional microphone placements, tape loops, double tracking and vari-speed recording, the Beatles augmented their songs with instruments that were unconventional in rock music at the time. These included string and brass ensembles as well as Indian instruments such as the sitar in "Norwegian Wood" and the swarmandal in "Strawberry Fields Forever".[404] They also used novel electronic instruments such as the Mellotron, with which McCartney supplied the flute voices on the "Strawberry Fields Forever" intro,[405] and the clavioline, an electronic keyboard that created the unusual oboe-like sound on "Baby, You're a Rich Man".[406]
+
+Former Rolling Stone associate editor Robert Greenfield compared the Beatles to Picasso, as "artists who broke through the constraints of their time period to come up with something that was unique and original ... [I]n the form of popular music, no one will ever be more revolutionary, more creative and more distinctive ..."[347] The British poet Philip Larkin described their work as "an enchanting and intoxicating hybrid of Negro rock-and-roll with their own adolescent romanticism", and "the first advance in popular music since the War".[408]
+
+They not only sparked the British Invasion of the US,[409] they became a globally influential phenomenon as well.[410] From the 1920s, the US had dominated popular entertainment culture throughout much of the world, via Hollywood films, jazz, the music of Broadway and Tin Pan Alley and, later, the rock and roll that first emerged in Memphis, Tennessee.[333] The Beatles are regarded as British cultural icons, with young adults from abroad naming the band among a group of people that they most associated with UK culture.[411][412]
+
+Their musical innovations and commercial success inspired musicians worldwide.[410] Many artists have acknowledged the Beatles' influence and enjoyed chart success with covers of their songs.[413] On radio, their arrival marked the beginning of a new era; in 1968 the programme director of New York's WABC radio station forbade his DJs from playing any "pre-Beatles" music, marking the defining line of what would be considered oldies on American radio.[414] They helped to redefine the album as something more than just a few hits padded out with "filler",[415] and they were primary innovators of the modern music video.[416] The Shea Stadium show with which they opened their 1965 North American tour attracted an estimated 55,600 people,[142] then the largest audience in concert history; Spitz describes the event as a "major breakthrough ... a giant step toward reshaping the concert business".[417] Emulation of their clothing and especially their hairstyles, which became a mark of rebellion, had a global impact on fashion.[100]
+
+According to Gould, the Beatles changed the way people listened to popular music and experienced its role in their lives. From what began as the Beatlemania fad, the group's popularity grew into what was seen as an embodiment of sociocultural movements of the decade. As icons of the 1960s counterculture, Gould continues, they became a catalyst for bohemianism and activism in various social and political arenas, fuelling movements such as women's liberation, gay liberation and environmentalism.[418] According to Peter Lavezzoli, after the "more popular than Jesus" controversy in 1966, the Beatles felt considerable pressure to say the right things and "began a concerted effort to spread a message of wisdom and higher consciousness".[167]
+
+Other commentators such as Mikal Gilmore and Todd Leopold have traced the inception of their socio-cultural impact earlier, interpreting even the Beatlemania period, particularly on their first visit to the US, as a key moment in the development of generational awareness.[98][419] Referring to their appearance on the Ed Sullivan Show Leopold states: "In many ways, the Sullivan appearance marked the beginning of a cultural revolution ... The Beatles were like aliens dropped into the United States of 1964."[419] According to Gilmore:
+
+Elvis Presley had shown us how rebellion could be fashioned into eye-opening style; the Beatles were showing us how style could have the impact of cultural revelation – or at least how a pop vision might be forged into an unimpeachable consensus.[98]
+
+Established in 2009, Global Beatles Day is an annual holiday on 25 June each year that honours and celebrates the ideals of the Beatles.[420] The date was chosen to commemorate the date the group participated in the BBC programme Our World in 1967, performing "All You Need Is Love" broadcast to an international audience.[421]
+
+In 1965, Queen Elizabeth II appointed Lennon, McCartney, Harrison and Starr Members of the Order of the British Empire (MBE).[131] The Beatles won the 1971 Academy Award for Best Original Song Score for the film Let It Be (1970).[294] The recipients of seven Grammy Awards[422] and fifteen Ivor Novello Awards,[423] the Beatles have six Diamond albums, as well as 20 Multi-Platinum albums, 16 Platinum albums and six Gold albums in the US.[305] In the UK, the Beatles have four Multi-Platinum albums, four Platinum albums, eight Gold albums and one Silver album.[306] They were inducted into the Rock and Roll Hall of Fame in 1988.[323]
+
+The best-selling band in history, the Beatles have sold more than 800 million physical and digital albums as of 2013[update].[424][nb 10] They have had more number-one albums on the UK charts, fifteen,[426] and sold more singles in the UK, 21.9 million, than any other act.[427] In 2004, Rolling Stone ranked the Beatles as the most significant and influential rock music artists of the last 50 years.[428] They ranked number one on Billboard magazine's list of the all-time most successful Hot 100 artists, released in 2008 to celebrate the US singles chart's 50th anniversary.[429] As of 2017[update], they hold the record for most number-one hits on the Billboard Hot 100, with twenty.[430] The Recording Industry Association of America certifies that the Beatles have sold 178 million units in the US, more than any other artist.[431] They were collectively included in Time magazine's compilation of the 20th century's 100 most influential people.[432] In 2014, they received the Grammy Lifetime Achievement Award.[433]
+
+On 16 January each year, beginning in 2001, people celebrate World Beatles Day under UNESCO. This date has direct relation to the opening of The Cavern Club in 1957.[434][435]
+
+Five asteroids, 4147 Lennon, 4148 McCartney, 4149 Harrison, 4150 Starr and 8749 Beatles are named after the Beatles. In 2007, the Beatles became the first band to feature on a series of UK postage stamps issued by the Royal Mail.[436]
+
+Principal members
+
+
+
+Early members
+
+Touring musician
+
+
+
+The Beatles have a core catalogue consisting of 13 studio albums and one compilation.[437]
+
+Core catalogue
+
+See also
+
+Through 1969, the Beatles' catalogue was published almost exclusively by Northern Songs Ltd, a company formed in February 1963 by music publisher Dick James specifically for Lennon and McCartney, though it later acquired songs by other artists. The company was organised with James and his partner, Emmanuel Silver, owning a controlling interest, variously described as 51% or 50% plus one share. McCartney had 20%. Reports again vary concerning Lennon's portion – 19 or 20% – and Brian Epstein's – 9 or 10% – which he received in lieu of a 25% band management fee.[438][439][440] In 1965, the company went public. Five million shares were created, of which the original principals retained 3.75 million. James and Silver each received 937,500 shares (18.75% of 5 million); Lennon and McCartney each received 750,000 shares (15%); and Epstein's management company, NEMS Enterprises, received 375,000 shares (7.5%). Of the 1.25 million shares put up for sale, Harrison and Starr each acquired 40,000.[441] At the time of the stock offering, Lennon and McCartney renewed their three-year publishing contracts, binding them to Northern Songs until 1973.[442]
+
+Harrison created Harrisongs to represent his Beatles compositions, but signed a three-year contract with Northern Songs that gave it the copyright to his work through March 1968, which included "Taxman" and "Within You Without You".[443] The songs on which Starr received co-writing credit before 1968, such as "What Goes On" and "Flying", were also Northern Songs copyrights.[444] Harrison did not renew his contract with Northern Songs when it ended, signing instead with Apple Publishing while retaining the copyright to his work from that point on. Harrison thus owns the rights to his later Beatles songs such as "While My Guitar Gently Weeps" and "Something". That year, as well, Starr created Startling Music, which holds the rights to his Beatles compositions, "Don't Pass Me By" and "Octopus's Garden".[445][446]
+
+In March 1969, James arranged to sell his and his partner's shares of Northern Songs to the British broadcasting company Associated Television (ATV), founded by impresario Lew Grade, without first informing the Beatles. The band then made a bid to gain a controlling interest by attempting to work out a deal with a consortium of London brokerage firms that had accumulated a 14% holding.[447] The deal collapsed over the objections of Lennon, who declared, "I'm sick of being fucked about by men in suits sitting on their fat arses in the City."[448] By the end of May, ATV had acquired a majority stake in Northern Songs, controlling nearly the entire Lennon–McCartney catalogue, as well as any future material until 1973.[449] In frustration, Lennon and McCartney sold their shares to ATV in late October 1969.[450]
+
+In 1981, financial losses by ATV's parent company, Associated Communications Corporation (ACC), led it to attempt to sell its music division. According to authors Brian Southall and Rupert Perry, Grade contacted McCartney, offering ATV Music and Northern Songs for $30 million.[451] According to an account McCartney gave in 1995, he met with Grade and explained he was interested solely in the Northern Songs catalogue if Grade were ever willing to "separate off" that portion of ATV Music. Soon afterwards, Grade offered to sell him Northern Songs for £20 million, giving the ex-Beatle "a week or so" to decide. By McCartney's account, he and Ono countered with a £5 million bid that was rejected.[452] According to reports at the time, Grade refused to separate Northern Songs and turned down an offer of £21–25 million from McCartney and Ono for Northern Songs. In 1982, ACC was acquired in a takeover by Australian business magnate Robert Holmes à Court for £60 million.[453]
+
+In 1985, Michael Jackson purchased ATV for a reported $47.5 million. The acquisition gave him control over the publishing rights to more than 200 Beatles songs, as well as 40,000 other copyrights.[454] In 1995, in a deal that earned him a reported $110 million, Jackson merged his music publishing business with Sony, creating a new company, Sony/ATV Music Publishing, in which he held a 50% stake. The merger made the new company, then valued at over half a billion dollars, the third-largest music publisher in the world.[455] In 2016, Sony acquired Jackson's share of Sony/ATV from the Jackson estate for $750 million.[456]
+
+Despite the lack of publishing rights to most of their songs, Lennon's estate and McCartney continue to receive their respective shares of the writers' royalties, which together are 33​1⁄3% of total commercial proceeds in the US and which vary elsewhere around the world between 50 and 55%.[457] Two of Lennon and McCartney's earliest songs – "Love Me Do" and "P.S. I Love You" – were published by an EMI subsidiary, Ardmore & Beechwood, before they signed with James. McCartney acquired their publishing rights from Ardmore[458] in 1978,[459] and they are the only two Beatles songs owned by McCartney's company MPL Communications.[460] On 18 January 2017, McCartney filed a suit in the United States district court against Sony/ATV Music Publishing seeking to reclaim ownership of his share of the Lennon–McCartney song catalogue beginning in 2018. Under US copyright law, for works published before 1978 the author can reclaim copyrights assigned to a publisher after 56 years.[461][462] McCartney and Sony agreed to a confidential settlement in June 2017.[463][464]
+
+Fictionalised
+
+Documentaries and filmed performances
+
+1963
+
+1964
+
+1965
+
+1966
+

en/6030.html.txt

@@ -0,0 +1,112 @@
+
+
+A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
+
+Earth's volcanoes occur because its crust is broken into 17 major, rigid tectonic plates that float on a hotter, softer layer in its mantle.[1] Therefore, on Earth, volcanoes are generally found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-oceanic ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, e.g., in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande Rift in North America. This type of volcanism falls under the umbrella of "plate hypothesis" volcanism.[2] Volcanism away from plate boundaries has also been explained as mantle plumes. These so-called "hotspots", for example Hawaii, are postulated to arise from upwelling diapirs with magma from the core–mantle boundary, 3,000 km deep in the Earth.  Volcanoes are usually not created where two tectonic plates slide past one another.
+
+Large eruptions can affect ambient temperature as ash and droplets of sulfuric acid obscure the sun and cool the Earth's  troposphere; historically, large volcanic eruptions have been followed by volcanic winters which have caused catastrophic famines.
+
+The word volcano is derived from the name of Vulcano, a volcanic island in the Aeolian Islands of Italy whose name in turn comes from Vulcan, the god of fire in Roman mythology.[3] The study of volcanoes is called volcanology, sometimes spelled vulcanology.
+
+At the mid-oceanic ridges, two tectonic plates diverge from one another as new oceanic crust is formed by the cooling and solidifying of hot molten rock. Because the crust is very thin at these ridges due to the pull of the tectonic plates, the release of pressure leads to adiabatic expansion (without transfer of heat or matter) and the partial melting of the mantle, causing volcanism and creating new oceanic crust. Most divergent plate boundaries are at the bottom of the oceans; therefore, most volcanic activity on the Earth is submarine, forming new seafloor. Black smokers (also known as deep sea vents) are evidence of this kind of volcanic activity. Where the mid-oceanic ridge is above sea-level, volcanic islands are formed; for example, Iceland.
+
+Subduction zones are places where two plates, usually an oceanic plate and a continental plate, collide. In this case, the oceanic plate subducts, or submerges, under the continental plate, forming a deep ocean trench just offshore. In a process called flux melting, water released from the subducting plate lowers the melting temperature of the overlying mantle wedge, thus creating magma. This magma tends to be extremely  viscous because of its high silica content, so it often does not attain the surface but cools and solidifies at depth.  When it does reach the surface, however, a volcano is formed. Typical examples are Mount Etna and the volcanoes in the Pacific Ring of Fire.
+
+Hotspots are volcanic areas believed to be formed by mantle plumes, which are hypothesized to be columns of hot material rising from the core-mantle boundary in a fixed space that causes large-volume melting. Because tectonic plates move across them, each volcano becomes dormant and is eventually re-formed as the plate advances over the postulated plume. The Hawaiian Islands are said to have been formed in such a manner; so has the Snake River Plain, with the Yellowstone Caldera being the part of the North American plate above the hot spot. This theory, however, has been doubted.[2]
+
+The most common perception of a volcano is of a conical mountain, spewing lava and poisonous gases from a crater at its summit; however, this describes just one of the many types of volcano.  The features of volcanoes are much more complicated and their structure and behavior depends on a number of factors. Some volcanoes have rugged peaks formed by lava domes rather than a summit crater while others have landscape features such as massive plateaus. Vents that issue volcanic material (including lava and ash) and gases (mainly steam and magmatic gases) can develop anywhere on the landform and may give rise to smaller cones such as Puʻu ʻŌʻō on a flank of Hawaii's Kīlauea.
+Other types of volcano include cryovolcanoes (or ice volcanoes), particularly on some moons of Jupiter, Saturn, and Neptune; and mud volcanoes, which are formations often not associated with known magmatic activity. Active mud volcanoes tend to involve temperatures much lower than those of igneous volcanoes except when the mud volcano is actually a vent of an igneous volcano.
+
+Volcanic fissure vents are flat, linear fractures through which lava emerges.
+
+Shield volcanoes, so named for their broad, shield-like profiles, are formed by the eruption of low-viscosity lava that can flow a great distance from a vent. They generally do not explode catastrophically. Since low-viscosity magma is typically low in silica, shield volcanoes are more common in oceanic than continental settings. The Hawaiian volcanic chain is a series of shield cones, and they are common in Iceland, as well.
+
+Lava domes are built by slow eruptions of highly viscous lava. They are sometimes formed within the crater of a previous volcanic eruption, as in the case of Mount Saint Helens, but can also form independently, as in the case of Lassen Peak. Like stratovolcanoes, they can produce violent, explosive eruptions, but their lava generally does not flow far from the originating vent.
+
+Cryptodomes are formed when viscous lava is forced upward causing the surface to bulge. The 1980 eruption of Mount St. Helens was an example; lava beneath the surface of the mountain created an upward bulge which slid down the north side of the mountain.
+
+Volcanic cones or cinder cones result from eruptions of mostly small pieces of scoria and pyroclastics (both resemble cinders, hence the name of this volcano type) that build up around the vent. These can be relatively short-lived eruptions that produce a cone-shaped hill perhaps 30 to 400 meters high. Most cinder cones erupt only once. Cinder cones may form as flank vents on larger volcanoes, or occur on their own.  Parícutin in Mexico and Sunset Crater in Arizona are examples of cinder cones.  In New Mexico, Caja del Rio is a volcanic field of over 60 cinder cones.
+
+Based on satellite images it was suggested that cinder cones might occur on other terrestrial bodies in the Solar system too; on the surface of Mars and the Moon.[4][5][6][7]
+
+Stratovolcanoes or composite volcanoes are tall conical mountains composed of lava flows and other ejecta in alternate layers, the strata that gives rise to the name. Stratovolcanoes are also known as composite volcanoes because they are created from multiple structures during different kinds of eruptions. Strato/composite volcanoes are made of cinders, ash, and lava. Cinders and ash pile on top of each other, lava flows on top of the ash, where it cools and hardens, and then the process repeats. Classic examples include Mount Fuji in Japan, Mayon Volcano in the Philippines, and Mount Vesuvius and Stromboli in Italy.
+
+Throughout recorded history, ash produced by the explosive eruption of stratovolcanoes has posed the greatest volcanic hazard to civilizations. Not only do stratovolcanoes have greater pressure buildup from the underlying lava flow than shield volcanoes, but their fissure vents and monogenetic volcanic fields (volcanic cones) also have more powerful eruptions because they are often under extension. They are also steeper than shield volcanoes, with slopes of 30–35° compared to slopes of generally 5–10°, and their loose tephra are material for dangerous lahars.[8] Large pieces of tephra are called volcanic bombs. Big bombs can measure more than 4 feet(1.2 meters) across and weigh several tons.[9]
+
+A supervolcano usually has a large caldera and can produce devastation on an enormous, sometimes continental, scale. Such volcanoes are able to severely cool global temperatures for many years after the eruption due to the huge volumes of sulfur and ash released into the atmosphere. They are the most dangerous type of volcano. Examples include Yellowstone Caldera in Yellowstone National Park and Valles Caldera in New Mexico (both western United States); Lake Taupo in New Zealand; Lake Toba in Sumatra, Indonesia; and Ngorongoro Crater in Tanzania. Because of the enormous area they may cover, supervolcanoes are hard to identify centuries after an eruption. Similarly, large igneous provinces are also considered supervolcanoes because of the vast amount of basalt lava erupted (even though the lava flow is non-explosive).
+
+Submarine volcanoes are common features of the ocean floor. In shallow water, active volcanoes disclose their presence by blasting steam and rocky debris high above the ocean's surface. In the ocean's deep, the tremendous weight of the water above prevents the explosive release of steam and gases; however, they can be detected by hydrophones and discoloration of water because of volcanic gases. Pillow lava is a common eruptive product of submarine volcanoes and is characterized by thick sequences of discontinuous pillow-shaped masses which form under water. Even large submarine eruptions may not disturb the ocean surface due to the rapid cooling effect and increased buoyancy of water (as compared to air) which often causes volcanic vents to form steep pillars on the ocean floor. Hydrothermal vents are common near these volcanoes, and some support peculiar ecosystems based on dissolved minerals. Over time, the formations created by submarine volcanoes may become so large that they break the ocean surface as new islands or floating pumice rafts.
+
+In 2018, a multitude of seismic signals were detected by earthquake monitoring agencies all over the world in May and June. They created a weird humming sound and some of the signals detected in November of that year had a duration of up to 20 minutes. An oceanographic campaign in May 2019 showed that the previously mysterious humming noises were caused by the formation of an underwater volcano off the coast of Mayotte.[10]
+
+Subglacial volcanoes develop underneath icecaps. They are made up of flat lava which flows at the top of extensive pillow lavas and palagonite. When the icecap melts, the lava on top collapses, leaving a flat-topped mountain. These volcanoes are also called table mountains, tuyas, or (uncommonly) mobergs. Very good examples of this type of volcano can be seen in Iceland, however, there are also tuyas in British Columbia. The origin of the term comes from Tuya Butte, which is one of the several tuyas in the area of the Tuya River and Tuya Range in northern British Columbia. Tuya Butte was the first such landform analyzed and so its name has entered the geological literature for this kind of volcanic formation. The Tuya Mountains Provincial Park was recently established to protect this unusual landscape, which lies north of Tuya Lake and south of the Jennings River near the boundary with the Yukon Territory.
+
+Mud volcanoes or mud domes are formations created by geo-excreted liquids and gases, although there are several processes which may cause such activity. The largest structures are 10 kilometers in diameter and reach 700 meters high.
+
+Another way of classifying volcanoes is by the composition of material erupted (lava), since this affects the shape of the volcano. Lava can be broadly classified into four different compositions:[11]
+
+Two types of lava are named according to the surface texture: ʻAʻa (pronounced [ˈʔaʔa]) and pāhoehoe ([paːˈho.eˈho.e]), both Hawaiian words. ʻAʻa is characterized by a rough, clinkery surface and is the typical texture of viscous lava flows. However, even basaltic or mafic flows can be erupted as ʻaʻa flows, particularly if the eruption rate is high and the slope is steep.
+
+Pāhoehoe is characterized by its smooth and often ropey or wrinkly surface and is generally formed from more fluid lava flows. Usually, only mafic flows will erupt as pāhoehoe, since they often erupt at higher temperatures or have the proper chemical make-up to allow them to flow with greater fluidity.
+
+A popular way of classifying magmatic volcanoes is by their frequency of eruption[according to whom?], with those that erupt regularly called active, those that have erupted in historical times but are now quiet called dormant or inactive, and those that have not erupted in historical times called extinct. However, these popular classifications—extinct in particular—are practically meaningless to scientists. They use classifications which refer to a particular volcano's formative and eruptive processes and resulting shapes.
+
+There is no consensus among volcanologists on how to define an "active" volcano. The lifespan of a volcano can vary from months to several million years, making such a distinction sometimes meaningless when compared to the lifespans of humans or even civilizations. For example, many of Earth's volcanoes have erupted dozens of times in the past few thousand years but are not currently showing signs of eruption. Given the long lifespan of such volcanoes, they are very active. By human lifespans, however, they are not.
+
+Scientists usually consider a volcano to be erupting or likely to erupt if it is currently erupting, or showing signs of unrest such as unusual earthquake activity or significant new gas emissions. Most scientists consider a volcano active if it has erupted in the last 10,000 years (Holocene times)—the Smithsonian Global Volcanism Program uses this definition of active. Most volcanoes are situated on the Pacific Ring of Fire.[12] An estimated 500 million people live near active volcanoes.[12]
+
+Historical time (or recorded history) is another timeframe for active.[13][14] The Catalogue of the Active Volcanoes of the World, published by the International Association of Volcanology, uses this definition, by which there are more than 500 active volcanoes.[13] However, the span of recorded history differs from region to region. In China and the Mediterranean, it reaches back nearly 3,000 years, but in the Pacific Northwest of the United States and Canada, it reaches back less than 300 years, and in Hawaii and New Zealand, only around 200 years.[13]
+
+As of 2013, the following are considered Earth's most active volcanoes:[15]
+
+As of 2010[update], the longest ongoing (but not necessarily continuous) volcanic eruptive phases are:[16]
+
+Other very active volcanoes include:
+
+Extinct volcanoes are those that scientists consider unlikely to erupt again because the volcano no longer has a magma supply. Examples of extinct volcanoes are many volcanoes on the Hawaiian – Emperor seamount chain in the Pacific Ocean (although some volcanoes at the eastern end of the chain are active), Hohentwiel in Germany, Shiprock in New Mexico, Zuidwal volcano in the Netherlands and many volcanoes in Italy like Monte Vulture. Edinburgh Castle in Scotland is famously located atop an extinct volcano. Otherwise, whether a volcano is truly extinct is often difficult to determine. Since "supervolcano" calderas can have eruptive lifespans sometimes measured in millions of years, a caldera that has not produced an eruption in tens of thousands of years is likely to be considered dormant instead of extinct. Some volcanologists refer to extinct volcanoes as inactive, though the term is now more commonly used for dormant volcanoes once thought to be extinct.
+
+It is difficult to distinguish an extinct volcano from a dormant (inactive) one. Dormant volcanoes are those that have not erupted for thousands of years, but are likely to erupt again in the future.[17][18] Volcanoes are often considered to be extinct if there are no written records of its activity. Nevertheless, volcanoes may remain dormant for a long period of time. For example,  Yellowstone has a repose/recharge period of around 700,000 years, and Toba of around 380,000 years.[19] Vesuvius was described by Roman writers as having been covered with gardens and vineyards before its eruption of 79 CE, which destroyed the towns of Herculaneum and Pompeii. Before its catastrophic eruption of 1991, Pinatubo was an inconspicuous volcano, unknown to most people in the surrounding areas. Two other examples are the long-dormant Soufrière Hills volcano on the island of Montserrat, thought to be extinct before activity resumed in 1995, and Fourpeaked Mountain in Alaska, which, before its September 2006 eruption, had not erupted since before 8000 BCE and had long been thought to be extinct.
+
+The three common popular classifications of volcanoes can be subjective and some volcanoes thought to have been extinct have erupted again. To help prevent people from falsely believing they are not at risk when living on or near a volcano, countries have adopted new classifications to describe the various levels and stages of volcanic activity.[20]  Some alert systems use different numbers or colors to designate the different stages.  Other systems use colors and words.  Some systems use a combination of both.
+
+The United States Geological Survey (USGS) has adopted a common system nationwide for characterizing the level of unrest and eruptive activity at volcanoes. The new volcano alert-level system classifies volcanoes now as being in a normal, advisory, watch or warning stage.  Additionally, colors are used to denote the amount of ash produced.
+
+The Decade Volcanoes are 16 volcanoes identified by the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) as being worthy of particular study in light of their history of large, destructive eruptions and proximity to populated areas. They are named Decade Volcanoes because the project was initiated as part of the United Nations-sponsored International Decade for Natural Disaster Reduction (the 1990s). The 16 current Decade Volcanoes are
+
+The Deep Earth Carbon Degassing Project, an initiative of the Deep Carbon Observatory, monitors nine volcanoes, two of which are Decade volcanoes. The focus of the Deep Earth Carbon Degassing Project is to use Multi-Component Gas Analyzer System instruments to measure CO2/SO2 ratios in real-time and in high-resolution to allow detection of the pre-eruptive degassing of rising magmas, improving prediction of volcanic activity.[21]
+
+There are many different types of volcanic eruptions and associated activity: phreatic eruptions (steam-generated eruptions), explosive eruption of high-silica lava (e.g., rhyolite), effusive eruption of low-silica lava (e.g., basalt), pyroclastic flows, lahars (debris flow) and carbon dioxide emission. All of these activities can pose a hazard to humans. Earthquakes, hot springs, fumaroles, mud pots and geysers often accompany volcanic activity.
+
+The concentrations of different volcanic gases can vary considerably from one volcano to the next. Water vapor is typically the most abundant volcanic gas, followed by carbon dioxide[22] and sulfur dioxide. Other principal volcanic gases include hydrogen sulfide, hydrogen chloride, and hydrogen fluoride. A large number of minor and trace gases are also found in volcanic emissions, for example hydrogen, carbon monoxide, halocarbons, organic compounds, and volatile metal chlorides.
+
+Large, explosive volcanic eruptions inject water vapor (H2O), carbon dioxide (CO2), sulfur dioxide (SO2), hydrogen chloride (HCl), hydrogen fluoride (HF) and ash (pulverized rock and pumice) into the stratosphere to heights of 16–32 kilometres (10–20 mi) above the Earth's surface. The most significant impacts from these injections come from the conversion of sulfur dioxide to sulfuric acid (H2SO4), which condenses rapidly in the stratosphere to form fine sulfate aerosols. The SO2 emissions alone of two different eruptions are sufficient to compare their potential climatic impact.[23] The aerosols increase the Earth's albedo—its reflection of radiation from the Sun back into space—and thus cool the Earth's lower atmosphere or troposphere; however, they also absorb heat radiated up from the Earth, thereby warming the stratosphere. Several eruptions during the past century have caused a decline in the average temperature at the Earth's surface of up to half a degree (Fahrenheit scale) for periods of one to three years; sulfur dioxide from the eruption of Huaynaputina probably caused the Russian famine of 1601–1603.[24]
+
+A volcanic winter is thought to have taken place around 70,000 years ago after the supereruption of Lake Toba on Sumatra island in Indonesia.[25] According to the Toba catastrophe theory to which some anthropologists and archeologists subscribe, it had global consequences,[26] killing most humans then alive and creating a population bottleneck that affected the genetic inheritance of all humans today.[27]
+
+It has been suggested that volcanic activity caused or contributed to the End-Ordovician, Permian-Triassic, Late Devonian mass extinctions, and possibly others. The massive eruptive event which formed the Siberian Traps, one of the largest known volcanic events of the last 500 million years of Earth's geological history, continued for a million years and is considered to be the likely cause of the "Great Dying" about 250 million years ago,[28] which is estimated to have killed 90% of species existing at the time.[29]
+
+The 1815 eruption of Mount Tambora created global climate anomalies that became known as the "Year Without a Summer" because of the effect on North American and European weather.[30] Agricultural crops failed and livestock died in much of the Northern Hemisphere, resulting in one of the worst famines of the 19th century.[31]
+
+The freezing winter of 1740–41, which led to widespread famine in northern Europe, may also owe its origins to a volcanic eruption.[32]
+
+Sulfate aerosols promote complex chemical reactions on their surfaces that alter chlorine and nitrogen chemical species in the stratosphere. This effect, together with increased stratospheric chlorine levels from chlorofluorocarbon pollution, generates chlorine monoxide (ClO), which destroys ozone (O3). As the aerosols grow and coagulate, they settle down into the upper troposphere where they serve as nuclei for cirrus clouds and further modify the Earth's radiation balance. Most of the hydrogen chloride (HCl) and hydrogen fluoride (HF) are dissolved in water droplets in the eruption cloud and quickly fall to the ground as acid rain. The injected ash also falls rapidly from the stratosphere; most of it is removed within several days to a few weeks. Finally, explosive volcanic eruptions release the greenhouse gas carbon dioxide and thus provide a deep source of carbon for biogeochemical cycles.[33]
+
+Gas emissions from volcanoes are a natural contributor to acid rain. Volcanic activity releases about 130 to 230 teragrams (145 million to 255 million short tons) of carbon dioxide each year.[34] Volcanic eruptions may inject aerosols into the Earth's atmosphere. Large injections may cause visual effects such as unusually colorful sunsets and affect global climate mainly by cooling it. Volcanic eruptions also provide the benefit of adding nutrients to soil through the weathering process of volcanic rocks. These fertile soils assist the growth of plants and various crops. Volcanic eruptions can also create new islands, as the magma cools and solidifies upon contact with the water.
+
+Ash thrown into the air by eruptions can present a hazard to aircraft, especially jet aircraft where the particles can be melted by the high operating temperature; the melted particles then adhere to the turbine blades and alter their shape, disrupting the operation of the turbine.  Dangerous encounters in 1982 after the eruption of Galunggung in Indonesia, and 1989 after the eruption of Mount Redoubt in Alaska raised awareness of this phenomenon.  Nine Volcanic Ash Advisory Centers were established by the International Civil Aviation Organization to monitor ash clouds and advise pilots accordingly.  The 2010 eruptions of Eyjafjallajökull caused major disruptions to air travel in Europe.
+
+The Earth's Moon has no large volcanoes and no current volcanic activity, although recent evidence suggests it may still possess a partially molten core.[35] However, the Moon does have many volcanic features such as maria (the darker patches seen on the moon), rilles and domes.
+
+The planet Venus has a surface that is 90% basalt, indicating that volcanism played a major role in shaping its surface. The planet may have had a major global resurfacing event about 500 million years ago,[36] from what scientists can tell from the density of impact craters on the surface. Lava flows are widespread and forms of volcanism not present on Earth occur as well. Changes in the planet's atmosphere and observations of lightning have been attributed to ongoing volcanic eruptions, although there is no confirmation of whether or not Venus is still volcanically active. However, radar sounding by the Magellan probe revealed evidence for comparatively recent volcanic activity at Venus's highest volcano Maat Mons, in the form of ash flows near the summit and on the northern flank.
+
+There are several extinct volcanoes on Mars, four of which are vast shield volcanoes far bigger than any on Earth. They include Arsia Mons, Ascraeus Mons, Hecates Tholus, Olympus Mons, and Pavonis Mons. These volcanoes have been extinct for many millions of years,[37] but the European Mars Express spacecraft has found evidence that volcanic activity may have occurred on Mars in the recent past as well.[37]
+
+Jupiter's moon Io is the most volcanically active object in the solar system because of tidal interaction with Jupiter. It is covered with volcanoes that erupt sulfur, sulfur dioxide and silicate rock, and as a result, Io is constantly being resurfaced. Its lavas are the hottest known anywhere in the solar system, with temperatures exceeding 1,800 K (1,500 °C). In February 2001, the largest recorded volcanic eruptions in the solar system occurred on Io.[38] Europa, the smallest of Jupiter's Galilean moons, also appears to have an active volcanic system, except that its volcanic activity is entirely in the form of water, which freezes into ice on the frigid surface. This process is known as cryovolcanism, and is apparently most common on the moons of the outer planets of the solar system.
+
+In 1989, the Voyager 2 spacecraft observed cryovolcanoes (ice volcanoes) on Triton, a moon of Neptune, and in 2005 the Cassini–Huygens probe photographed fountains of frozen particles erupting from Enceladus, a moon of Saturn.[39][40] The ejecta may be composed of water, liquid nitrogen, ammonia, dust, or methane compounds. Cassini–Huygens also found evidence of a methane-spewing cryovolcano on the Saturnian moon Titan, which is believed to be a significant source of the methane found in its atmosphere.[41] It is theorized that cryovolcanism may also be present on the Kuiper Belt Object Quaoar.
+
+A 2010 study of the exoplanet COROT-7b, which was detected by transit in 2009, suggested that tidal heating from the host star very close to the planet and neighboring planets could generate intense volcanic activity similar to that found on Io.[42]
+
+Many ancient accounts ascribe volcanic eruptions to supernatural causes, such as the actions of gods or demigods. To the ancient Greeks, volcanoes' capricious power could only be explained as acts of the gods, while 16th/17th-century German astronomer Johannes Kepler believed they were ducts for the Earth's tears.[43]  One early idea counter to this was proposed by Jesuit Athanasius Kircher (1602–1680), who witnessed eruptions of Mount Etna and Stromboli, then visited the crater of Vesuvius and published his view of an Earth with a central fire connected to numerous others caused by the burning of sulfur, bitumen and coal.
+
+Various explanations were proposed for volcano behavior before the modern understanding of the Earth's mantle structure as a semisolid material was developed. For decades after awareness that compression and radioactive materials may be heat sources, their contributions were specifically discounted. Volcanic action was often attributed to chemical reactions and a thin layer of molten rock near the surface.

en/6031.html.txt

@@ -0,0 +1,112 @@
+
+
+A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
+
+Earth's volcanoes occur because its crust is broken into 17 major, rigid tectonic plates that float on a hotter, softer layer in its mantle.[1] Therefore, on Earth, volcanoes are generally found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-oceanic ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, e.g., in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande Rift in North America. This type of volcanism falls under the umbrella of "plate hypothesis" volcanism.[2] Volcanism away from plate boundaries has also been explained as mantle plumes. These so-called "hotspots", for example Hawaii, are postulated to arise from upwelling diapirs with magma from the core–mantle boundary, 3,000 km deep in the Earth.  Volcanoes are usually not created where two tectonic plates slide past one another.
+
+Large eruptions can affect ambient temperature as ash and droplets of sulfuric acid obscure the sun and cool the Earth's  troposphere; historically, large volcanic eruptions have been followed by volcanic winters which have caused catastrophic famines.
+
+The word volcano is derived from the name of Vulcano, a volcanic island in the Aeolian Islands of Italy whose name in turn comes from Vulcan, the god of fire in Roman mythology.[3] The study of volcanoes is called volcanology, sometimes spelled vulcanology.
+
+At the mid-oceanic ridges, two tectonic plates diverge from one another as new oceanic crust is formed by the cooling and solidifying of hot molten rock. Because the crust is very thin at these ridges due to the pull of the tectonic plates, the release of pressure leads to adiabatic expansion (without transfer of heat or matter) and the partial melting of the mantle, causing volcanism and creating new oceanic crust. Most divergent plate boundaries are at the bottom of the oceans; therefore, most volcanic activity on the Earth is submarine, forming new seafloor. Black smokers (also known as deep sea vents) are evidence of this kind of volcanic activity. Where the mid-oceanic ridge is above sea-level, volcanic islands are formed; for example, Iceland.
+
+Subduction zones are places where two plates, usually an oceanic plate and a continental plate, collide. In this case, the oceanic plate subducts, or submerges, under the continental plate, forming a deep ocean trench just offshore. In a process called flux melting, water released from the subducting plate lowers the melting temperature of the overlying mantle wedge, thus creating magma. This magma tends to be extremely  viscous because of its high silica content, so it often does not attain the surface but cools and solidifies at depth.  When it does reach the surface, however, a volcano is formed. Typical examples are Mount Etna and the volcanoes in the Pacific Ring of Fire.
+
+Hotspots are volcanic areas believed to be formed by mantle plumes, which are hypothesized to be columns of hot material rising from the core-mantle boundary in a fixed space that causes large-volume melting. Because tectonic plates move across them, each volcano becomes dormant and is eventually re-formed as the plate advances over the postulated plume. The Hawaiian Islands are said to have been formed in such a manner; so has the Snake River Plain, with the Yellowstone Caldera being the part of the North American plate above the hot spot. This theory, however, has been doubted.[2]
+
+The most common perception of a volcano is of a conical mountain, spewing lava and poisonous gases from a crater at its summit; however, this describes just one of the many types of volcano.  The features of volcanoes are much more complicated and their structure and behavior depends on a number of factors. Some volcanoes have rugged peaks formed by lava domes rather than a summit crater while others have landscape features such as massive plateaus. Vents that issue volcanic material (including lava and ash) and gases (mainly steam and magmatic gases) can develop anywhere on the landform and may give rise to smaller cones such as Puʻu ʻŌʻō on a flank of Hawaii's Kīlauea.
+Other types of volcano include cryovolcanoes (or ice volcanoes), particularly on some moons of Jupiter, Saturn, and Neptune; and mud volcanoes, which are formations often not associated with known magmatic activity. Active mud volcanoes tend to involve temperatures much lower than those of igneous volcanoes except when the mud volcano is actually a vent of an igneous volcano.
+
+Volcanic fissure vents are flat, linear fractures through which lava emerges.
+
+Shield volcanoes, so named for their broad, shield-like profiles, are formed by the eruption of low-viscosity lava that can flow a great distance from a vent. They generally do not explode catastrophically. Since low-viscosity magma is typically low in silica, shield volcanoes are more common in oceanic than continental settings. The Hawaiian volcanic chain is a series of shield cones, and they are common in Iceland, as well.
+
+Lava domes are built by slow eruptions of highly viscous lava. They are sometimes formed within the crater of a previous volcanic eruption, as in the case of Mount Saint Helens, but can also form independently, as in the case of Lassen Peak. Like stratovolcanoes, they can produce violent, explosive eruptions, but their lava generally does not flow far from the originating vent.
+
+Cryptodomes are formed when viscous lava is forced upward causing the surface to bulge. The 1980 eruption of Mount St. Helens was an example; lava beneath the surface of the mountain created an upward bulge which slid down the north side of the mountain.
+
+Volcanic cones or cinder cones result from eruptions of mostly small pieces of scoria and pyroclastics (both resemble cinders, hence the name of this volcano type) that build up around the vent. These can be relatively short-lived eruptions that produce a cone-shaped hill perhaps 30 to 400 meters high. Most cinder cones erupt only once. Cinder cones may form as flank vents on larger volcanoes, or occur on their own.  Parícutin in Mexico and Sunset Crater in Arizona are examples of cinder cones.  In New Mexico, Caja del Rio is a volcanic field of over 60 cinder cones.
+
+Based on satellite images it was suggested that cinder cones might occur on other terrestrial bodies in the Solar system too; on the surface of Mars and the Moon.[4][5][6][7]
+
+Stratovolcanoes or composite volcanoes are tall conical mountains composed of lava flows and other ejecta in alternate layers, the strata that gives rise to the name. Stratovolcanoes are also known as composite volcanoes because they are created from multiple structures during different kinds of eruptions. Strato/composite volcanoes are made of cinders, ash, and lava. Cinders and ash pile on top of each other, lava flows on top of the ash, where it cools and hardens, and then the process repeats. Classic examples include Mount Fuji in Japan, Mayon Volcano in the Philippines, and Mount Vesuvius and Stromboli in Italy.
+
+Throughout recorded history, ash produced by the explosive eruption of stratovolcanoes has posed the greatest volcanic hazard to civilizations. Not only do stratovolcanoes have greater pressure buildup from the underlying lava flow than shield volcanoes, but their fissure vents and monogenetic volcanic fields (volcanic cones) also have more powerful eruptions because they are often under extension. They are also steeper than shield volcanoes, with slopes of 30–35° compared to slopes of generally 5–10°, and their loose tephra are material for dangerous lahars.[8] Large pieces of tephra are called volcanic bombs. Big bombs can measure more than 4 feet(1.2 meters) across and weigh several tons.[9]
+
+A supervolcano usually has a large caldera and can produce devastation on an enormous, sometimes continental, scale. Such volcanoes are able to severely cool global temperatures for many years after the eruption due to the huge volumes of sulfur and ash released into the atmosphere. They are the most dangerous type of volcano. Examples include Yellowstone Caldera in Yellowstone National Park and Valles Caldera in New Mexico (both western United States); Lake Taupo in New Zealand; Lake Toba in Sumatra, Indonesia; and Ngorongoro Crater in Tanzania. Because of the enormous area they may cover, supervolcanoes are hard to identify centuries after an eruption. Similarly, large igneous provinces are also considered supervolcanoes because of the vast amount of basalt lava erupted (even though the lava flow is non-explosive).
+
+Submarine volcanoes are common features of the ocean floor. In shallow water, active volcanoes disclose their presence by blasting steam and rocky debris high above the ocean's surface. In the ocean's deep, the tremendous weight of the water above prevents the explosive release of steam and gases; however, they can be detected by hydrophones and discoloration of water because of volcanic gases. Pillow lava is a common eruptive product of submarine volcanoes and is characterized by thick sequences of discontinuous pillow-shaped masses which form under water. Even large submarine eruptions may not disturb the ocean surface due to the rapid cooling effect and increased buoyancy of water (as compared to air) which often causes volcanic vents to form steep pillars on the ocean floor. Hydrothermal vents are common near these volcanoes, and some support peculiar ecosystems based on dissolved minerals. Over time, the formations created by submarine volcanoes may become so large that they break the ocean surface as new islands or floating pumice rafts.
+
+In 2018, a multitude of seismic signals were detected by earthquake monitoring agencies all over the world in May and June. They created a weird humming sound and some of the signals detected in November of that year had a duration of up to 20 minutes. An oceanographic campaign in May 2019 showed that the previously mysterious humming noises were caused by the formation of an underwater volcano off the coast of Mayotte.[10]
+
+Subglacial volcanoes develop underneath icecaps. They are made up of flat lava which flows at the top of extensive pillow lavas and palagonite. When the icecap melts, the lava on top collapses, leaving a flat-topped mountain. These volcanoes are also called table mountains, tuyas, or (uncommonly) mobergs. Very good examples of this type of volcano can be seen in Iceland, however, there are also tuyas in British Columbia. The origin of the term comes from Tuya Butte, which is one of the several tuyas in the area of the Tuya River and Tuya Range in northern British Columbia. Tuya Butte was the first such landform analyzed and so its name has entered the geological literature for this kind of volcanic formation. The Tuya Mountains Provincial Park was recently established to protect this unusual landscape, which lies north of Tuya Lake and south of the Jennings River near the boundary with the Yukon Territory.
+
+Mud volcanoes or mud domes are formations created by geo-excreted liquids and gases, although there are several processes which may cause such activity. The largest structures are 10 kilometers in diameter and reach 700 meters high.
+
+Another way of classifying volcanoes is by the composition of material erupted (lava), since this affects the shape of the volcano. Lava can be broadly classified into four different compositions:[11]
+
+Two types of lava are named according to the surface texture: ʻAʻa (pronounced [ˈʔaʔa]) and pāhoehoe ([paːˈho.eˈho.e]), both Hawaiian words. ʻAʻa is characterized by a rough, clinkery surface and is the typical texture of viscous lava flows. However, even basaltic or mafic flows can be erupted as ʻaʻa flows, particularly if the eruption rate is high and the slope is steep.
+
+Pāhoehoe is characterized by its smooth and often ropey or wrinkly surface and is generally formed from more fluid lava flows. Usually, only mafic flows will erupt as pāhoehoe, since they often erupt at higher temperatures or have the proper chemical make-up to allow them to flow with greater fluidity.
+
+A popular way of classifying magmatic volcanoes is by their frequency of eruption[according to whom?], with those that erupt regularly called active, those that have erupted in historical times but are now quiet called dormant or inactive, and those that have not erupted in historical times called extinct. However, these popular classifications—extinct in particular—are practically meaningless to scientists. They use classifications which refer to a particular volcano's formative and eruptive processes and resulting shapes.
+
+There is no consensus among volcanologists on how to define an "active" volcano. The lifespan of a volcano can vary from months to several million years, making such a distinction sometimes meaningless when compared to the lifespans of humans or even civilizations. For example, many of Earth's volcanoes have erupted dozens of times in the past few thousand years but are not currently showing signs of eruption. Given the long lifespan of such volcanoes, they are very active. By human lifespans, however, they are not.
+
+Scientists usually consider a volcano to be erupting or likely to erupt if it is currently erupting, or showing signs of unrest such as unusual earthquake activity or significant new gas emissions. Most scientists consider a volcano active if it has erupted in the last 10,000 years (Holocene times)—the Smithsonian Global Volcanism Program uses this definition of active. Most volcanoes are situated on the Pacific Ring of Fire.[12] An estimated 500 million people live near active volcanoes.[12]
+
+Historical time (or recorded history) is another timeframe for active.[13][14] The Catalogue of the Active Volcanoes of the World, published by the International Association of Volcanology, uses this definition, by which there are more than 500 active volcanoes.[13] However, the span of recorded history differs from region to region. In China and the Mediterranean, it reaches back nearly 3,000 years, but in the Pacific Northwest of the United States and Canada, it reaches back less than 300 years, and in Hawaii and New Zealand, only around 200 years.[13]
+
+As of 2013, the following are considered Earth's most active volcanoes:[15]
+
+As of 2010[update], the longest ongoing (but not necessarily continuous) volcanic eruptive phases are:[16]
+
+Other very active volcanoes include:
+
+Extinct volcanoes are those that scientists consider unlikely to erupt again because the volcano no longer has a magma supply. Examples of extinct volcanoes are many volcanoes on the Hawaiian – Emperor seamount chain in the Pacific Ocean (although some volcanoes at the eastern end of the chain are active), Hohentwiel in Germany, Shiprock in New Mexico, Zuidwal volcano in the Netherlands and many volcanoes in Italy like Monte Vulture. Edinburgh Castle in Scotland is famously located atop an extinct volcano. Otherwise, whether a volcano is truly extinct is often difficult to determine. Since "supervolcano" calderas can have eruptive lifespans sometimes measured in millions of years, a caldera that has not produced an eruption in tens of thousands of years is likely to be considered dormant instead of extinct. Some volcanologists refer to extinct volcanoes as inactive, though the term is now more commonly used for dormant volcanoes once thought to be extinct.
+
+It is difficult to distinguish an extinct volcano from a dormant (inactive) one. Dormant volcanoes are those that have not erupted for thousands of years, but are likely to erupt again in the future.[17][18] Volcanoes are often considered to be extinct if there are no written records of its activity. Nevertheless, volcanoes may remain dormant for a long period of time. For example,  Yellowstone has a repose/recharge period of around 700,000 years, and Toba of around 380,000 years.[19] Vesuvius was described by Roman writers as having been covered with gardens and vineyards before its eruption of 79 CE, which destroyed the towns of Herculaneum and Pompeii. Before its catastrophic eruption of 1991, Pinatubo was an inconspicuous volcano, unknown to most people in the surrounding areas. Two other examples are the long-dormant Soufrière Hills volcano on the island of Montserrat, thought to be extinct before activity resumed in 1995, and Fourpeaked Mountain in Alaska, which, before its September 2006 eruption, had not erupted since before 8000 BCE and had long been thought to be extinct.
+
+The three common popular classifications of volcanoes can be subjective and some volcanoes thought to have been extinct have erupted again. To help prevent people from falsely believing they are not at risk when living on or near a volcano, countries have adopted new classifications to describe the various levels and stages of volcanic activity.[20]  Some alert systems use different numbers or colors to designate the different stages.  Other systems use colors and words.  Some systems use a combination of both.
+
+The United States Geological Survey (USGS) has adopted a common system nationwide for characterizing the level of unrest and eruptive activity at volcanoes. The new volcano alert-level system classifies volcanoes now as being in a normal, advisory, watch or warning stage.  Additionally, colors are used to denote the amount of ash produced.
+
+The Decade Volcanoes are 16 volcanoes identified by the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) as being worthy of particular study in light of their history of large, destructive eruptions and proximity to populated areas. They are named Decade Volcanoes because the project was initiated as part of the United Nations-sponsored International Decade for Natural Disaster Reduction (the 1990s). The 16 current Decade Volcanoes are
+
+The Deep Earth Carbon Degassing Project, an initiative of the Deep Carbon Observatory, monitors nine volcanoes, two of which are Decade volcanoes. The focus of the Deep Earth Carbon Degassing Project is to use Multi-Component Gas Analyzer System instruments to measure CO2/SO2 ratios in real-time and in high-resolution to allow detection of the pre-eruptive degassing of rising magmas, improving prediction of volcanic activity.[21]
+
+There are many different types of volcanic eruptions and associated activity: phreatic eruptions (steam-generated eruptions), explosive eruption of high-silica lava (e.g., rhyolite), effusive eruption of low-silica lava (e.g., basalt), pyroclastic flows, lahars (debris flow) and carbon dioxide emission. All of these activities can pose a hazard to humans. Earthquakes, hot springs, fumaroles, mud pots and geysers often accompany volcanic activity.
+
+The concentrations of different volcanic gases can vary considerably from one volcano to the next. Water vapor is typically the most abundant volcanic gas, followed by carbon dioxide[22] and sulfur dioxide. Other principal volcanic gases include hydrogen sulfide, hydrogen chloride, and hydrogen fluoride. A large number of minor and trace gases are also found in volcanic emissions, for example hydrogen, carbon monoxide, halocarbons, organic compounds, and volatile metal chlorides.
+
+Large, explosive volcanic eruptions inject water vapor (H2O), carbon dioxide (CO2), sulfur dioxide (SO2), hydrogen chloride (HCl), hydrogen fluoride (HF) and ash (pulverized rock and pumice) into the stratosphere to heights of 16–32 kilometres (10–20 mi) above the Earth's surface. The most significant impacts from these injections come from the conversion of sulfur dioxide to sulfuric acid (H2SO4), which condenses rapidly in the stratosphere to form fine sulfate aerosols. The SO2 emissions alone of two different eruptions are sufficient to compare their potential climatic impact.[23] The aerosols increase the Earth's albedo—its reflection of radiation from the Sun back into space—and thus cool the Earth's lower atmosphere or troposphere; however, they also absorb heat radiated up from the Earth, thereby warming the stratosphere. Several eruptions during the past century have caused a decline in the average temperature at the Earth's surface of up to half a degree (Fahrenheit scale) for periods of one to three years; sulfur dioxide from the eruption of Huaynaputina probably caused the Russian famine of 1601–1603.[24]
+
+A volcanic winter is thought to have taken place around 70,000 years ago after the supereruption of Lake Toba on Sumatra island in Indonesia.[25] According to the Toba catastrophe theory to which some anthropologists and archeologists subscribe, it had global consequences,[26] killing most humans then alive and creating a population bottleneck that affected the genetic inheritance of all humans today.[27]
+
+It has been suggested that volcanic activity caused or contributed to the End-Ordovician, Permian-Triassic, Late Devonian mass extinctions, and possibly others. The massive eruptive event which formed the Siberian Traps, one of the largest known volcanic events of the last 500 million years of Earth's geological history, continued for a million years and is considered to be the likely cause of the "Great Dying" about 250 million years ago,[28] which is estimated to have killed 90% of species existing at the time.[29]
+
+The 1815 eruption of Mount Tambora created global climate anomalies that became known as the "Year Without a Summer" because of the effect on North American and European weather.[30] Agricultural crops failed and livestock died in much of the Northern Hemisphere, resulting in one of the worst famines of the 19th century.[31]
+
+The freezing winter of 1740–41, which led to widespread famine in northern Europe, may also owe its origins to a volcanic eruption.[32]
+
+Sulfate aerosols promote complex chemical reactions on their surfaces that alter chlorine and nitrogen chemical species in the stratosphere. This effect, together with increased stratospheric chlorine levels from chlorofluorocarbon pollution, generates chlorine monoxide (ClO), which destroys ozone (O3). As the aerosols grow and coagulate, they settle down into the upper troposphere where they serve as nuclei for cirrus clouds and further modify the Earth's radiation balance. Most of the hydrogen chloride (HCl) and hydrogen fluoride (HF) are dissolved in water droplets in the eruption cloud and quickly fall to the ground as acid rain. The injected ash also falls rapidly from the stratosphere; most of it is removed within several days to a few weeks. Finally, explosive volcanic eruptions release the greenhouse gas carbon dioxide and thus provide a deep source of carbon for biogeochemical cycles.[33]
+
+Gas emissions from volcanoes are a natural contributor to acid rain. Volcanic activity releases about 130 to 230 teragrams (145 million to 255 million short tons) of carbon dioxide each year.[34] Volcanic eruptions may inject aerosols into the Earth's atmosphere. Large injections may cause visual effects such as unusually colorful sunsets and affect global climate mainly by cooling it. Volcanic eruptions also provide the benefit of adding nutrients to soil through the weathering process of volcanic rocks. These fertile soils assist the growth of plants and various crops. Volcanic eruptions can also create new islands, as the magma cools and solidifies upon contact with the water.
+
+Ash thrown into the air by eruptions can present a hazard to aircraft, especially jet aircraft where the particles can be melted by the high operating temperature; the melted particles then adhere to the turbine blades and alter their shape, disrupting the operation of the turbine.  Dangerous encounters in 1982 after the eruption of Galunggung in Indonesia, and 1989 after the eruption of Mount Redoubt in Alaska raised awareness of this phenomenon.  Nine Volcanic Ash Advisory Centers were established by the International Civil Aviation Organization to monitor ash clouds and advise pilots accordingly.  The 2010 eruptions of Eyjafjallajökull caused major disruptions to air travel in Europe.
+
+The Earth's Moon has no large volcanoes and no current volcanic activity, although recent evidence suggests it may still possess a partially molten core.[35] However, the Moon does have many volcanic features such as maria (the darker patches seen on the moon), rilles and domes.
+
+The planet Venus has a surface that is 90% basalt, indicating that volcanism played a major role in shaping its surface. The planet may have had a major global resurfacing event about 500 million years ago,[36] from what scientists can tell from the density of impact craters on the surface. Lava flows are widespread and forms of volcanism not present on Earth occur as well. Changes in the planet's atmosphere and observations of lightning have been attributed to ongoing volcanic eruptions, although there is no confirmation of whether or not Venus is still volcanically active. However, radar sounding by the Magellan probe revealed evidence for comparatively recent volcanic activity at Venus's highest volcano Maat Mons, in the form of ash flows near the summit and on the northern flank.
+
+There are several extinct volcanoes on Mars, four of which are vast shield volcanoes far bigger than any on Earth. They include Arsia Mons, Ascraeus Mons, Hecates Tholus, Olympus Mons, and Pavonis Mons. These volcanoes have been extinct for many millions of years,[37] but the European Mars Express spacecraft has found evidence that volcanic activity may have occurred on Mars in the recent past as well.[37]
+
+Jupiter's moon Io is the most volcanically active object in the solar system because of tidal interaction with Jupiter. It is covered with volcanoes that erupt sulfur, sulfur dioxide and silicate rock, and as a result, Io is constantly being resurfaced. Its lavas are the hottest known anywhere in the solar system, with temperatures exceeding 1,800 K (1,500 °C). In February 2001, the largest recorded volcanic eruptions in the solar system occurred on Io.[38] Europa, the smallest of Jupiter's Galilean moons, also appears to have an active volcanic system, except that its volcanic activity is entirely in the form of water, which freezes into ice on the frigid surface. This process is known as cryovolcanism, and is apparently most common on the moons of the outer planets of the solar system.
+
+In 1989, the Voyager 2 spacecraft observed cryovolcanoes (ice volcanoes) on Triton, a moon of Neptune, and in 2005 the Cassini–Huygens probe photographed fountains of frozen particles erupting from Enceladus, a moon of Saturn.[39][40] The ejecta may be composed of water, liquid nitrogen, ammonia, dust, or methane compounds. Cassini–Huygens also found evidence of a methane-spewing cryovolcano on the Saturnian moon Titan, which is believed to be a significant source of the methane found in its atmosphere.[41] It is theorized that cryovolcanism may also be present on the Kuiper Belt Object Quaoar.
+
+A 2010 study of the exoplanet COROT-7b, which was detected by transit in 2009, suggested that tidal heating from the host star very close to the planet and neighboring planets could generate intense volcanic activity similar to that found on Io.[42]
+
+Many ancient accounts ascribe volcanic eruptions to supernatural causes, such as the actions of gods or demigods. To the ancient Greeks, volcanoes' capricious power could only be explained as acts of the gods, while 16th/17th-century German astronomer Johannes Kepler believed they were ducts for the Earth's tears.[43]  One early idea counter to this was proposed by Jesuit Athanasius Kircher (1602–1680), who witnessed eruptions of Mount Etna and Stromboli, then visited the crater of Vesuvius and published his view of an Earth with a central fire connected to numerous others caused by the burning of sulfur, bitumen and coal.
+
+Various explanations were proposed for volcano behavior before the modern understanding of the Earth's mantle structure as a semisolid material was developed. For decades after awareness that compression and radioactive materials may be heat sources, their contributions were specifically discounted. Volcanic action was often attributed to chemical reactions and a thin layer of molten rock near the surface.

en/6032.html.txt

@@ -0,0 +1,112 @@
+
+
+A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
+
+Earth's volcanoes occur because its crust is broken into 17 major, rigid tectonic plates that float on a hotter, softer layer in its mantle.[1] Therefore, on Earth, volcanoes are generally found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-oceanic ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, e.g., in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande Rift in North America. This type of volcanism falls under the umbrella of "plate hypothesis" volcanism.[2] Volcanism away from plate boundaries has also been explained as mantle plumes. These so-called "hotspots", for example Hawaii, are postulated to arise from upwelling diapirs with magma from the core–mantle boundary, 3,000 km deep in the Earth.  Volcanoes are usually not created where two tectonic plates slide past one another.
+
+Large eruptions can affect ambient temperature as ash and droplets of sulfuric acid obscure the sun and cool the Earth's  troposphere; historically, large volcanic eruptions have been followed by volcanic winters which have caused catastrophic famines.
+
+The word volcano is derived from the name of Vulcano, a volcanic island in the Aeolian Islands of Italy whose name in turn comes from Vulcan, the god of fire in Roman mythology.[3] The study of volcanoes is called volcanology, sometimes spelled vulcanology.
+
+At the mid-oceanic ridges, two tectonic plates diverge from one another as new oceanic crust is formed by the cooling and solidifying of hot molten rock. Because the crust is very thin at these ridges due to the pull of the tectonic plates, the release of pressure leads to adiabatic expansion (without transfer of heat or matter) and the partial melting of the mantle, causing volcanism and creating new oceanic crust. Most divergent plate boundaries are at the bottom of the oceans; therefore, most volcanic activity on the Earth is submarine, forming new seafloor. Black smokers (also known as deep sea vents) are evidence of this kind of volcanic activity. Where the mid-oceanic ridge is above sea-level, volcanic islands are formed; for example, Iceland.
+
+Subduction zones are places where two plates, usually an oceanic plate and a continental plate, collide. In this case, the oceanic plate subducts, or submerges, under the continental plate, forming a deep ocean trench just offshore. In a process called flux melting, water released from the subducting plate lowers the melting temperature of the overlying mantle wedge, thus creating magma. This magma tends to be extremely  viscous because of its high silica content, so it often does not attain the surface but cools and solidifies at depth.  When it does reach the surface, however, a volcano is formed. Typical examples are Mount Etna and the volcanoes in the Pacific Ring of Fire.
+
+Hotspots are volcanic areas believed to be formed by mantle plumes, which are hypothesized to be columns of hot material rising from the core-mantle boundary in a fixed space that causes large-volume melting. Because tectonic plates move across them, each volcano becomes dormant and is eventually re-formed as the plate advances over the postulated plume. The Hawaiian Islands are said to have been formed in such a manner; so has the Snake River Plain, with the Yellowstone Caldera being the part of the North American plate above the hot spot. This theory, however, has been doubted.[2]
+
+The most common perception of a volcano is of a conical mountain, spewing lava and poisonous gases from a crater at its summit; however, this describes just one of the many types of volcano.  The features of volcanoes are much more complicated and their structure and behavior depends on a number of factors. Some volcanoes have rugged peaks formed by lava domes rather than a summit crater while others have landscape features such as massive plateaus. Vents that issue volcanic material (including lava and ash) and gases (mainly steam and magmatic gases) can develop anywhere on the landform and may give rise to smaller cones such as Puʻu ʻŌʻō on a flank of Hawaii's Kīlauea.
+Other types of volcano include cryovolcanoes (or ice volcanoes), particularly on some moons of Jupiter, Saturn, and Neptune; and mud volcanoes, which are formations often not associated with known magmatic activity. Active mud volcanoes tend to involve temperatures much lower than those of igneous volcanoes except when the mud volcano is actually a vent of an igneous volcano.
+
+Volcanic fissure vents are flat, linear fractures through which lava emerges.
+
+Shield volcanoes, so named for their broad, shield-like profiles, are formed by the eruption of low-viscosity lava that can flow a great distance from a vent. They generally do not explode catastrophically. Since low-viscosity magma is typically low in silica, shield volcanoes are more common in oceanic than continental settings. The Hawaiian volcanic chain is a series of shield cones, and they are common in Iceland, as well.
+
+Lava domes are built by slow eruptions of highly viscous lava. They are sometimes formed within the crater of a previous volcanic eruption, as in the case of Mount Saint Helens, but can also form independently, as in the case of Lassen Peak. Like stratovolcanoes, they can produce violent, explosive eruptions, but their lava generally does not flow far from the originating vent.
+
+Cryptodomes are formed when viscous lava is forced upward causing the surface to bulge. The 1980 eruption of Mount St. Helens was an example; lava beneath the surface of the mountain created an upward bulge which slid down the north side of the mountain.
+
+Volcanic cones or cinder cones result from eruptions of mostly small pieces of scoria and pyroclastics (both resemble cinders, hence the name of this volcano type) that build up around the vent. These can be relatively short-lived eruptions that produce a cone-shaped hill perhaps 30 to 400 meters high. Most cinder cones erupt only once. Cinder cones may form as flank vents on larger volcanoes, or occur on their own.  Parícutin in Mexico and Sunset Crater in Arizona are examples of cinder cones.  In New Mexico, Caja del Rio is a volcanic field of over 60 cinder cones.
+
+Based on satellite images it was suggested that cinder cones might occur on other terrestrial bodies in the Solar system too; on the surface of Mars and the Moon.[4][5][6][7]
+
+Stratovolcanoes or composite volcanoes are tall conical mountains composed of lava flows and other ejecta in alternate layers, the strata that gives rise to the name. Stratovolcanoes are also known as composite volcanoes because they are created from multiple structures during different kinds of eruptions. Strato/composite volcanoes are made of cinders, ash, and lava. Cinders and ash pile on top of each other, lava flows on top of the ash, where it cools and hardens, and then the process repeats. Classic examples include Mount Fuji in Japan, Mayon Volcano in the Philippines, and Mount Vesuvius and Stromboli in Italy.
+
+Throughout recorded history, ash produced by the explosive eruption of stratovolcanoes has posed the greatest volcanic hazard to civilizations. Not only do stratovolcanoes have greater pressure buildup from the underlying lava flow than shield volcanoes, but their fissure vents and monogenetic volcanic fields (volcanic cones) also have more powerful eruptions because they are often under extension. They are also steeper than shield volcanoes, with slopes of 30–35° compared to slopes of generally 5–10°, and their loose tephra are material for dangerous lahars.[8] Large pieces of tephra are called volcanic bombs. Big bombs can measure more than 4 feet(1.2 meters) across and weigh several tons.[9]
+
+A supervolcano usually has a large caldera and can produce devastation on an enormous, sometimes continental, scale. Such volcanoes are able to severely cool global temperatures for many years after the eruption due to the huge volumes of sulfur and ash released into the atmosphere. They are the most dangerous type of volcano. Examples include Yellowstone Caldera in Yellowstone National Park and Valles Caldera in New Mexico (both western United States); Lake Taupo in New Zealand; Lake Toba in Sumatra, Indonesia; and Ngorongoro Crater in Tanzania. Because of the enormous area they may cover, supervolcanoes are hard to identify centuries after an eruption. Similarly, large igneous provinces are also considered supervolcanoes because of the vast amount of basalt lava erupted (even though the lava flow is non-explosive).
+
+Submarine volcanoes are common features of the ocean floor. In shallow water, active volcanoes disclose their presence by blasting steam and rocky debris high above the ocean's surface. In the ocean's deep, the tremendous weight of the water above prevents the explosive release of steam and gases; however, they can be detected by hydrophones and discoloration of water because of volcanic gases. Pillow lava is a common eruptive product of submarine volcanoes and is characterized by thick sequences of discontinuous pillow-shaped masses which form under water. Even large submarine eruptions may not disturb the ocean surface due to the rapid cooling effect and increased buoyancy of water (as compared to air) which often causes volcanic vents to form steep pillars on the ocean floor. Hydrothermal vents are common near these volcanoes, and some support peculiar ecosystems based on dissolved minerals. Over time, the formations created by submarine volcanoes may become so large that they break the ocean surface as new islands or floating pumice rafts.
+
+In 2018, a multitude of seismic signals were detected by earthquake monitoring agencies all over the world in May and June. They created a weird humming sound and some of the signals detected in November of that year had a duration of up to 20 minutes. An oceanographic campaign in May 2019 showed that the previously mysterious humming noises were caused by the formation of an underwater volcano off the coast of Mayotte.[10]
+
+Subglacial volcanoes develop underneath icecaps. They are made up of flat lava which flows at the top of extensive pillow lavas and palagonite. When the icecap melts, the lava on top collapses, leaving a flat-topped mountain. These volcanoes are also called table mountains, tuyas, or (uncommonly) mobergs. Very good examples of this type of volcano can be seen in Iceland, however, there are also tuyas in British Columbia. The origin of the term comes from Tuya Butte, which is one of the several tuyas in the area of the Tuya River and Tuya Range in northern British Columbia. Tuya Butte was the first such landform analyzed and so its name has entered the geological literature for this kind of volcanic formation. The Tuya Mountains Provincial Park was recently established to protect this unusual landscape, which lies north of Tuya Lake and south of the Jennings River near the boundary with the Yukon Territory.
+
+Mud volcanoes or mud domes are formations created by geo-excreted liquids and gases, although there are several processes which may cause such activity. The largest structures are 10 kilometers in diameter and reach 700 meters high.
+
+Another way of classifying volcanoes is by the composition of material erupted (lava), since this affects the shape of the volcano. Lava can be broadly classified into four different compositions:[11]
+
+Two types of lava are named according to the surface texture: ʻAʻa (pronounced [ˈʔaʔa]) and pāhoehoe ([paːˈho.eˈho.e]), both Hawaiian words. ʻAʻa is characterized by a rough, clinkery surface and is the typical texture of viscous lava flows. However, even basaltic or mafic flows can be erupted as ʻaʻa flows, particularly if the eruption rate is high and the slope is steep.
+
+Pāhoehoe is characterized by its smooth and often ropey or wrinkly surface and is generally formed from more fluid lava flows. Usually, only mafic flows will erupt as pāhoehoe, since they often erupt at higher temperatures or have the proper chemical make-up to allow them to flow with greater fluidity.
+
+A popular way of classifying magmatic volcanoes is by their frequency of eruption[according to whom?], with those that erupt regularly called active, those that have erupted in historical times but are now quiet called dormant or inactive, and those that have not erupted in historical times called extinct. However, these popular classifications—extinct in particular—are practically meaningless to scientists. They use classifications which refer to a particular volcano's formative and eruptive processes and resulting shapes.
+
+There is no consensus among volcanologists on how to define an "active" volcano. The lifespan of a volcano can vary from months to several million years, making such a distinction sometimes meaningless when compared to the lifespans of humans or even civilizations. For example, many of Earth's volcanoes have erupted dozens of times in the past few thousand years but are not currently showing signs of eruption. Given the long lifespan of such volcanoes, they are very active. By human lifespans, however, they are not.
+
+Scientists usually consider a volcano to be erupting or likely to erupt if it is currently erupting, or showing signs of unrest such as unusual earthquake activity or significant new gas emissions. Most scientists consider a volcano active if it has erupted in the last 10,000 years (Holocene times)—the Smithsonian Global Volcanism Program uses this definition of active. Most volcanoes are situated on the Pacific Ring of Fire.[12] An estimated 500 million people live near active volcanoes.[12]
+
+Historical time (or recorded history) is another timeframe for active.[13][14] The Catalogue of the Active Volcanoes of the World, published by the International Association of Volcanology, uses this definition, by which there are more than 500 active volcanoes.[13] However, the span of recorded history differs from region to region. In China and the Mediterranean, it reaches back nearly 3,000 years, but in the Pacific Northwest of the United States and Canada, it reaches back less than 300 years, and in Hawaii and New Zealand, only around 200 years.[13]
+
+As of 2013, the following are considered Earth's most active volcanoes:[15]
+
+As of 2010[update], the longest ongoing (but not necessarily continuous) volcanic eruptive phases are:[16]
+
+Other very active volcanoes include:
+
+Extinct volcanoes are those that scientists consider unlikely to erupt again because the volcano no longer has a magma supply. Examples of extinct volcanoes are many volcanoes on the Hawaiian – Emperor seamount chain in the Pacific Ocean (although some volcanoes at the eastern end of the chain are active), Hohentwiel in Germany, Shiprock in New Mexico, Zuidwal volcano in the Netherlands and many volcanoes in Italy like Monte Vulture. Edinburgh Castle in Scotland is famously located atop an extinct volcano. Otherwise, whether a volcano is truly extinct is often difficult to determine. Since "supervolcano" calderas can have eruptive lifespans sometimes measured in millions of years, a caldera that has not produced an eruption in tens of thousands of years is likely to be considered dormant instead of extinct. Some volcanologists refer to extinct volcanoes as inactive, though the term is now more commonly used for dormant volcanoes once thought to be extinct.
+
+It is difficult to distinguish an extinct volcano from a dormant (inactive) one. Dormant volcanoes are those that have not erupted for thousands of years, but are likely to erupt again in the future.[17][18] Volcanoes are often considered to be extinct if there are no written records of its activity. Nevertheless, volcanoes may remain dormant for a long period of time. For example,  Yellowstone has a repose/recharge period of around 700,000 years, and Toba of around 380,000 years.[19] Vesuvius was described by Roman writers as having been covered with gardens and vineyards before its eruption of 79 CE, which destroyed the towns of Herculaneum and Pompeii. Before its catastrophic eruption of 1991, Pinatubo was an inconspicuous volcano, unknown to most people in the surrounding areas. Two other examples are the long-dormant Soufrière Hills volcano on the island of Montserrat, thought to be extinct before activity resumed in 1995, and Fourpeaked Mountain in Alaska, which, before its September 2006 eruption, had not erupted since before 8000 BCE and had long been thought to be extinct.
+
+The three common popular classifications of volcanoes can be subjective and some volcanoes thought to have been extinct have erupted again. To help prevent people from falsely believing they are not at risk when living on or near a volcano, countries have adopted new classifications to describe the various levels and stages of volcanic activity.[20]  Some alert systems use different numbers or colors to designate the different stages.  Other systems use colors and words.  Some systems use a combination of both.
+
+The United States Geological Survey (USGS) has adopted a common system nationwide for characterizing the level of unrest and eruptive activity at volcanoes. The new volcano alert-level system classifies volcanoes now as being in a normal, advisory, watch or warning stage.  Additionally, colors are used to denote the amount of ash produced.
+
+The Decade Volcanoes are 16 volcanoes identified by the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) as being worthy of particular study in light of their history of large, destructive eruptions and proximity to populated areas. They are named Decade Volcanoes because the project was initiated as part of the United Nations-sponsored International Decade for Natural Disaster Reduction (the 1990s). The 16 current Decade Volcanoes are
+
+The Deep Earth Carbon Degassing Project, an initiative of the Deep Carbon Observatory, monitors nine volcanoes, two of which are Decade volcanoes. The focus of the Deep Earth Carbon Degassing Project is to use Multi-Component Gas Analyzer System instruments to measure CO2/SO2 ratios in real-time and in high-resolution to allow detection of the pre-eruptive degassing of rising magmas, improving prediction of volcanic activity.[21]
+
+There are many different types of volcanic eruptions and associated activity: phreatic eruptions (steam-generated eruptions), explosive eruption of high-silica lava (e.g., rhyolite), effusive eruption of low-silica lava (e.g., basalt), pyroclastic flows, lahars (debris flow) and carbon dioxide emission. All of these activities can pose a hazard to humans. Earthquakes, hot springs, fumaroles, mud pots and geysers often accompany volcanic activity.
+
+The concentrations of different volcanic gases can vary considerably from one volcano to the next. Water vapor is typically the most abundant volcanic gas, followed by carbon dioxide[22] and sulfur dioxide. Other principal volcanic gases include hydrogen sulfide, hydrogen chloride, and hydrogen fluoride. A large number of minor and trace gases are also found in volcanic emissions, for example hydrogen, carbon monoxide, halocarbons, organic compounds, and volatile metal chlorides.
+
+Large, explosive volcanic eruptions inject water vapor (H2O), carbon dioxide (CO2), sulfur dioxide (SO2), hydrogen chloride (HCl), hydrogen fluoride (HF) and ash (pulverized rock and pumice) into the stratosphere to heights of 16–32 kilometres (10–20 mi) above the Earth's surface. The most significant impacts from these injections come from the conversion of sulfur dioxide to sulfuric acid (H2SO4), which condenses rapidly in the stratosphere to form fine sulfate aerosols. The SO2 emissions alone of two different eruptions are sufficient to compare their potential climatic impact.[23] The aerosols increase the Earth's albedo—its reflection of radiation from the Sun back into space—and thus cool the Earth's lower atmosphere or troposphere; however, they also absorb heat radiated up from the Earth, thereby warming the stratosphere. Several eruptions during the past century have caused a decline in the average temperature at the Earth's surface of up to half a degree (Fahrenheit scale) for periods of one to three years; sulfur dioxide from the eruption of Huaynaputina probably caused the Russian famine of 1601–1603.[24]
+
+A volcanic winter is thought to have taken place around 70,000 years ago after the supereruption of Lake Toba on Sumatra island in Indonesia.[25] According to the Toba catastrophe theory to which some anthropologists and archeologists subscribe, it had global consequences,[26] killing most humans then alive and creating a population bottleneck that affected the genetic inheritance of all humans today.[27]
+
+It has been suggested that volcanic activity caused or contributed to the End-Ordovician, Permian-Triassic, Late Devonian mass extinctions, and possibly others. The massive eruptive event which formed the Siberian Traps, one of the largest known volcanic events of the last 500 million years of Earth's geological history, continued for a million years and is considered to be the likely cause of the "Great Dying" about 250 million years ago,[28] which is estimated to have killed 90% of species existing at the time.[29]
+
+The 1815 eruption of Mount Tambora created global climate anomalies that became known as the "Year Without a Summer" because of the effect on North American and European weather.[30] Agricultural crops failed and livestock died in much of the Northern Hemisphere, resulting in one of the worst famines of the 19th century.[31]
+
+The freezing winter of 1740–41, which led to widespread famine in northern Europe, may also owe its origins to a volcanic eruption.[32]
+
+Sulfate aerosols promote complex chemical reactions on their surfaces that alter chlorine and nitrogen chemical species in the stratosphere. This effect, together with increased stratospheric chlorine levels from chlorofluorocarbon pollution, generates chlorine monoxide (ClO), which destroys ozone (O3). As the aerosols grow and coagulate, they settle down into the upper troposphere where they serve as nuclei for cirrus clouds and further modify the Earth's radiation balance. Most of the hydrogen chloride (HCl) and hydrogen fluoride (HF) are dissolved in water droplets in the eruption cloud and quickly fall to the ground as acid rain. The injected ash also falls rapidly from the stratosphere; most of it is removed within several days to a few weeks. Finally, explosive volcanic eruptions release the greenhouse gas carbon dioxide and thus provide a deep source of carbon for biogeochemical cycles.[33]
+
+Gas emissions from volcanoes are a natural contributor to acid rain. Volcanic activity releases about 130 to 230 teragrams (145 million to 255 million short tons) of carbon dioxide each year.[34] Volcanic eruptions may inject aerosols into the Earth's atmosphere. Large injections may cause visual effects such as unusually colorful sunsets and affect global climate mainly by cooling it. Volcanic eruptions also provide the benefit of adding nutrients to soil through the weathering process of volcanic rocks. These fertile soils assist the growth of plants and various crops. Volcanic eruptions can also create new islands, as the magma cools and solidifies upon contact with the water.
+
+Ash thrown into the air by eruptions can present a hazard to aircraft, especially jet aircraft where the particles can be melted by the high operating temperature; the melted particles then adhere to the turbine blades and alter their shape, disrupting the operation of the turbine.  Dangerous encounters in 1982 after the eruption of Galunggung in Indonesia, and 1989 after the eruption of Mount Redoubt in Alaska raised awareness of this phenomenon.  Nine Volcanic Ash Advisory Centers were established by the International Civil Aviation Organization to monitor ash clouds and advise pilots accordingly.  The 2010 eruptions of Eyjafjallajökull caused major disruptions to air travel in Europe.
+
+The Earth's Moon has no large volcanoes and no current volcanic activity, although recent evidence suggests it may still possess a partially molten core.[35] However, the Moon does have many volcanic features such as maria (the darker patches seen on the moon), rilles and domes.
+
+The planet Venus has a surface that is 90% basalt, indicating that volcanism played a major role in shaping its surface. The planet may have had a major global resurfacing event about 500 million years ago,[36] from what scientists can tell from the density of impact craters on the surface. Lava flows are widespread and forms of volcanism not present on Earth occur as well. Changes in the planet's atmosphere and observations of lightning have been attributed to ongoing volcanic eruptions, although there is no confirmation of whether or not Venus is still volcanically active. However, radar sounding by the Magellan probe revealed evidence for comparatively recent volcanic activity at Venus's highest volcano Maat Mons, in the form of ash flows near the summit and on the northern flank.
+
+There are several extinct volcanoes on Mars, four of which are vast shield volcanoes far bigger than any on Earth. They include Arsia Mons, Ascraeus Mons, Hecates Tholus, Olympus Mons, and Pavonis Mons. These volcanoes have been extinct for many millions of years,[37] but the European Mars Express spacecraft has found evidence that volcanic activity may have occurred on Mars in the recent past as well.[37]
+
+Jupiter's moon Io is the most volcanically active object in the solar system because of tidal interaction with Jupiter. It is covered with volcanoes that erupt sulfur, sulfur dioxide and silicate rock, and as a result, Io is constantly being resurfaced. Its lavas are the hottest known anywhere in the solar system, with temperatures exceeding 1,800 K (1,500 °C). In February 2001, the largest recorded volcanic eruptions in the solar system occurred on Io.[38] Europa, the smallest of Jupiter's Galilean moons, also appears to have an active volcanic system, except that its volcanic activity is entirely in the form of water, which freezes into ice on the frigid surface. This process is known as cryovolcanism, and is apparently most common on the moons of the outer planets of the solar system.
+
+In 1989, the Voyager 2 spacecraft observed cryovolcanoes (ice volcanoes) on Triton, a moon of Neptune, and in 2005 the Cassini–Huygens probe photographed fountains of frozen particles erupting from Enceladus, a moon of Saturn.[39][40] The ejecta may be composed of water, liquid nitrogen, ammonia, dust, or methane compounds. Cassini–Huygens also found evidence of a methane-spewing cryovolcano on the Saturnian moon Titan, which is believed to be a significant source of the methane found in its atmosphere.[41] It is theorized that cryovolcanism may also be present on the Kuiper Belt Object Quaoar.
+
+A 2010 study of the exoplanet COROT-7b, which was detected by transit in 2009, suggested that tidal heating from the host star very close to the planet and neighboring planets could generate intense volcanic activity similar to that found on Io.[42]
+
+Many ancient accounts ascribe volcanic eruptions to supernatural causes, such as the actions of gods or demigods. To the ancient Greeks, volcanoes' capricious power could only be explained as acts of the gods, while 16th/17th-century German astronomer Johannes Kepler believed they were ducts for the Earth's tears.[43]  One early idea counter to this was proposed by Jesuit Athanasius Kircher (1602–1680), who witnessed eruptions of Mount Etna and Stromboli, then visited the crater of Vesuvius and published his view of an Earth with a central fire connected to numerous others caused by the burning of sulfur, bitumen and coal.
+
+Various explanations were proposed for volcano behavior before the modern understanding of the Earth's mantle structure as a semisolid material was developed. For decades after awareness that compression and radioactive materials may be heat sources, their contributions were specifically discounted. Volcanic action was often attributed to chemical reactions and a thin layer of molten rock near the surface.

en/6033.html.txt

@@ -0,0 +1,163 @@
+
+
+Volleyball is a team sport in which two teams of six players are separated by a net. Each team tries to score points by grounding a ball on the other team's court under organized rules.[1] It has been a part of the official program of the Summer Olympic Games since Tokyo 1964.
+
+The complete set of rules is extensive,[2] but play essentially proceeds as follows: a player on one of the teams begins a 'rally' by serving the ball (tossing or releasing it and then hitting it with a hand or arm), from behind the back boundary line of the court, over the net, and into the receiving team's court.[3] The receiving team must not let the ball be grounded within their court. The team may touch the ball up to 3 times, but individual players may not touch the ball twice consecutively.[3] Typically, the first two touches are used to set up for an attack, an attempt to direct the ball back over the net in such a way that the serving team is unable to prevent it from being grounded in their court.
+
+The rally continues, with each team allowed as many as three consecutive touches, until either (1): a team makes a kill, grounding the ball on the opponent's court and winning the rally; or (2): a team commits a fault and loses the rally. The team that wins the rally is awarded a point and serves the ball to start the next rally. A few of the most common faults include:
+
+The ball is usually played with the hands or arms, but players can legally strike or push (short contact) the ball with any part of the body.
+
+A number of consistent techniques have evolved in volleyball, including spiking and blocking (because these plays are made above the top of the net, the vertical jump is an athletic skill emphasized in the sport) as well as passing, setting, and specialized player positions and offensive and defensive structures.
+
+In the winter of 1895,[4] in Holyoke, Massachusetts (United States), William G. Morgan, a YMCA physical education director, created a new game called Mintonette, a name derived from the game of badminton,[5] as a pastime to be played (preferably) indoors and by any number of players. The game took some of its characteristics from other sports such as tennis and handball.[6] Another indoor sport, basketball, was catching on in the area, having been invented just ten miles (sixteen kilometres) away in the city of Springfield, Massachusetts, only four years before. Mintonette was designed to be an indoor sport, less rough than basketball, for older members of the YMCA, while still requiring a bit of athletic effort.
+
+The first rules, written down by William G Morgan, called for a net 6 ft 6 in (1.98 m) high, a 25 ft × 50 ft (7.6 m × 15.2 m) court, and any number of players. A match was composed of nine innings with three serves for each team in each inning, and no limit to the number of ball contacts for each team before sending the ball to the opponents' court. In case of a serving error, a second try was allowed. Hitting the ball into the net was considered a foul (with loss of the point or a side-out)—except in the case of the first-try serve.
+
+After an observer, Alfred Halstead, noticed the volleying nature of the game at its first exhibition match in 1896, played at the International YMCA Training School (now called Springfield College), the game quickly became known as volleyball (it was originally spelled as two words: "volley ball"). Volleyball rules were slightly modified by the International YMCA Training School and the game spread around the country to various YMCAs.[7][8]
+
+The first official ball used in volleyball is disputed; some sources say Spalding created the first official ball in 1896, while others claim it was created in 1900.[9][10][11] The rules evolved over time: in 1916, in the Philippines, the skill and power of the set and spike had been introduced, and four years later a "three hits" rule and a rule against hitting from the back row were established. In 1917, the game was changed from requiring 21 points to win to a smaller 15 points to win. In 1919, about 16,000 volleyballs were distributed by the American Expeditionary Forces to their troops and allies, which sparked the growth of volleyball in new countries.[9]
+
+The first country outside the United States to adopt volleyball was Canada in 1900.[9] An international federation, the Fédération Internationale de Volleyball (FIVB), was founded in 1947, and the first World Championships were held in 1949 for men and 1952 for women.[12] The sport is now popular in Brazil, in Europe (where especially Italy, the Netherlands, and countries from Eastern Europe have been major forces since the late 1980s), in Russia, and in other countries including China and the rest of Asia, as well as in the United States.[7][8][12]
+
+Beach volleyball, a variation of the game played on sand and with only two players per team, became a FIVB-endorsed variation in 1987 and was added to the Olympic program at the 1996 Summer Olympics.[9][12] Volleyball is also a sport at the Paralympics managed by the World Organization Volleyball for Disabled.
+
+Nudists were early adopters of the game with regular organized play in clubs as early as the late 1920s.[13][14] By the 1960s, a volleyball court had become standard in almost all nudist/naturist clubs.[15]
+
+Volleyball has been part of the Summer Olympics program for both men and women consistently since 1964.
+
+A volleyball court is 9 m × 18 m (29.5 ft × 59.1 ft), divided into equal square halves by a net with a width of one meter (39.4 in).[16] The top of the net is 2.43 m (7 ft 11 11⁄16 in) above the center of the court for men's competition, and 2.24 m (7 ft 4 3⁄16 in) for women's competition, varied for veterans and junior competitions.[3]
+
+The minimum height clearance for indoor volleyball courts is 7 m (23.0 ft), although a clearance of 8 m (26.2 ft) is recommended.[16]
+
+A line 3 m (9.8 ft) from and parallel to the net is considered the "attack line". This "3 meter" (or "10-foot") line divides the court into "back row" and "front row" areas (also back court and front court).[16] These are in turn divided into 3 areas each: these are numbered as follows, starting from area "1", which is the position of the serving player:
+
+After a team gains the serve (also known as siding out), its members must rotate in a clockwise direction, with the player previously in area "2" moving to area "1" and so on, with the player from area "1" moving to area "6".[3] Each player rotates only one time after the team gains possession of the service; the next time each player rotates will be after the other team wins possession of the ball and loses the point.[16]
+
+The team courts are surrounded by an area called the free zone which is a minimum of 3 meters wide and which the players may enter and play within after the service of the ball.[17] All lines denoting the boundaries of the team court and the attack zone are drawn or painted within the dimensions of the area and are therefore a part of the court or zone. If a ball comes in contact with the line, the ball is considered to be "in". An antenna is placed on each side of the net perpendicular to the sideline and is a vertical extension of the side boundary of the court. A ball passing over the net must pass completely between the antennae (or their theoretical extensions to the ceiling) without contacting them.[3]
+
+FIVB regulations state that the ball must be spherical, made of leather or synthetic leather, have a circumference of 65–67 cm, a weight of 260–280 g and an inside pressure of 0.30–0.325 kg/cm2.[18] Other governing bodies have similar regulations.
+
+Each team consists of six players.[16] To get play started, a team is chosen to serve by coin toss. A player from the serving team throws the ball into the air and attempts to hit the ball so it passes over the net on a course such that it will land in the opposing team's court (the serve).[16] The opposing team must use a combination of no more than three contacts with the volleyball to return the ball to the opponent's side of the net.[16] These contacts usually consist first of the bump or pass so that the ball's trajectory is aimed towards the player designated as the setter; second of the set (usually an over-hand pass using wrists to push finger-tips at the ball) by the setter so that the ball's trajectory is aimed towards a spot where one of the players designated as an attacker can hit it, and third by the attacker who spikes (jumping, raising one arm above the head and hitting the ball so it will move quickly down to the ground on the opponent's court) to return the ball over the net.[3] The team with possession of the ball that is trying to attack the ball as described is said to be on offence.
+
+The team on defence attempts to prevent the attacker from directing the ball into their court: players at the net jump and reach above the top (and if possible, across the plane) of the net to block the attacked ball.[3] If the ball is hit around, above, or through the block, the defensive players arranged in the rest of the court attempt to control the ball with a dig (usually a fore-arm pass of a hard-driven ball). After a successful dig, the team transitions to offence.
+
+The game continues in this manner, rallying back and forth until the ball touches the court within the boundaries or until an error is made.[16] The most frequent errors that are made are either to fail to return the ball over the net within the allowed three touches, or to cause the ball to land outside the court.[16] A ball is "in" if any part of it touches the inside of a team's court or a sideline or end-line, and a strong spike may compress the ball enough when it lands that a ball which at first appears to be going out may actually be in. Players may travel well outside the court to play a ball that has gone over a sideline or end-line in the air.
+
+Other common errors include a player touching the ball twice in succession, a player "catching" the ball, a player touching the net while attempting to play the ball, or a player penetrating under the net into the opponent's court. There are a large number of other errors specified in the rules, although most of them are infrequent occurrences. These errors include back-row or libero players spiking the ball or blocking (back-row players may spike the ball if they jump from behind the attack line), players not being in the correct position when the ball is served, attacking the serve in the frontcourt and above the height of the net, using another player as a source of support to reach the ball, stepping over the back boundary line when serving, taking more than 8 seconds to serve,[19] or playing the ball when it is above the opponent's court.
+
+A point is scored when the ball contacts the floor within the court boundaries or when an error is made: when the ball strikes one team's side of the court, the other team gains a point; and when an error is made, the team that did not make the error is awarded a point, in either case paying no regard to whether they served the ball or not. If any part of the ball hits the line, the ball is counted as in the court. The team that won the point serves for the next point. If the team that won the point served in the previous point, the same player serves again. If the team that won the point did not serve the previous point, the players of the team acquiring the serve rotate their position on the court in a clockwise manner. The game continues, with the first team to score 25 points by a two-point margin awarded the set. Matches are best-of-five sets and the fifth set, if necessary, is usually played to 15 points. (Scoring differs between leagues, tournaments, and levels; high schools sometimes play best-of-three to 25; in the NCAA matches are played best-of-five to 25 as of the 2008 season.)[20]
+
+Before 1999, points could be scored only when a team had the serve (side-out scoring) and all sets went up to only 15 points. The FIVB changed the rules in 1999 (with the changes being compulsory in 2000) to use the current scoring system (formerly known as rally point system), primarily to make the length of the match more predictable and to make the game more spectator- and television-friendly.
+
+The final year of side-out scoring at the NCAA Division I Women's Volleyball Championship was 2000. Rally point scoring debuted in 2001,[21] and games were played to 30 points through 2007. For the 2008 season, games were renamed "sets" and reduced to 25 points to win. Most high schools in the U.S. changed to rally scoring in 2003,[22][23][24] and several states implemented it the previous year on an experimental basis.[25]
+
+The libero player was introduced internationally in 1998,[26] and made its debut for NCAA competition in 2002.[27] The libero is a player specialized in defensive skills: the libero must wear a contrasting jersey color from their teammates and cannot block or attack the ball when it is entirely above net height. When the ball is not in play, the libero can replace any back-row player, without prior notice to the officials. This replacement does not count against the substitution limit each team is allowed per set, although the libero may be replaced only by the player whom he or she replaced. Most U.S. high schools added the libero position from 2003 to 2005.[23][28]
+
+The modern-day libero often takes on the role of a second setter. When the setter digs the ball, the libero is typically responsible for the second ball and sets to the front row attacker. The libero may function as a setter only under certain restrictions. To make an overhand set, the libero must be standing behind (and not stepping on) the 3-meter line; otherwise, the ball cannot be attacked above the net in front of the 3-meter line. An underhand pass is allowed from any part of the court.
+
+The libero is, generally, the most skilled defensive player on the team. There is also a libero tracking sheet, where the referees or officiating team must keep track of whom the libero subs in and out for. Under FIVB rules, two liberos are designated at the beginning of the play, only one of whom can be on the court at any time.
+
+Furthermore, a libero is not allowed to serve, according to international rules. NCAA rules for both men and women differ on this point; a 2004 rule change allows the libero to serve, but only in a specific rotation. That is, the libero can only serve for one person, not for all of the people for whom he or she goes in. That rule change was also applied to high school and junior high play soon after.
+
+Other rule changes enacted in 2000 include allowing serves in which the ball touches the net, as long as it goes over the net into the opponents' court. Also, the service area was expanded to allow players to serve from anywhere behind the end line but still within the theoretical extension of the sidelines. Other changes were made to lighten up calls on faults for carries and double-touches, such as allowing multiple contacts by a single player ("double-hits") on a team's first contact provided that they are a part of a single play on the ball.
+
+In 2008, the NCAA changed the minimum number of points needed to win any of the first four sets from 30 to 25 for women's volleyball (men's volleyball remained at 30 for another three years, switching to 25 in 2011.) If a fifth (deciding) set is reached, the minimum required score remains at 15. In addition, the word "game" is now referred to as "set".[20]
+
+The Official Volleyball Rules are prepared and updated every few years by the FIVB's Rules of the Game and Refereeing Commission.[29] The latest edition is usually available on the FIVB's website.[2]
+
+Competitive teams master six basic skills: serve, pass, set, attack, block and dig.[3] Each of these skills comprises a number of specific techniques that have been introduced over the years and are now considered standard practice in high-level volleyball.
+
+A player stands behind the inline and serves the ball, in an attempt to drive it into the opponent's court. The main objective is to make it land inside the court; it is also desirable to set the ball's direction, speed and acceleration so that it becomes difficult for the receiver to handle it properly.[3] A serve is called an "ace" when the ball lands directly onto the court or travels outside the court after being touched by an opponent; when the only player on the server's team to touch the ball is the server.
+
+In contemporary volleyball, many types of serves are employed:
+
+Also called reception, the pass is the attempt by a team to properly handle the opponent's serve or any form of attack. Proper handling includes not only preventing the ball from touching the court but also making it reach the position where the setter is standing quickly and precisely.[3]
+
+The skill of passing involves fundamentally two specific techniques: underarm pass, or bump, where the ball touches the inside part of the joined forearms or platform, at waistline; and overhand pass, where it is handled with the fingertips, like a set, above the head.[3] Either are acceptable in professional and beach volleyball; however, there are much tighter regulations on the overhand pass in beach volleyball. When a player passes a ball to their setter, it's ideal that the ball does not have a lot of spin to make it easier for the setter.
+
+The set is usually the second contact that a team makes with the ball.[3] The main goal of setting is to put the ball in the air in such a way that it can be driven by an attack into the opponent's court.[3] The setter coordinates the offensive movements of a team, and is the player who ultimately decides which player will actually attack the ball.
+
+As with passing, one may distinguish between an overhand and a bump set. Since the former allows for more control over the speed and direction of the ball, the bump is used only when the ball is so low it cannot be properly handled with fingertips, or in beach volleyball where rules regulating overhand setting are more stringent. In the case of a set, one also speaks of a front or back set, meaning whether the ball is passed in the direction the setter is facing or behind the setter. There is also a jump set that is used when the ball is too close to the net. In this case, the setter usually jumps off their right foot straight up to avoid going into the net. The setter usually stands about ⅔ of the way from the left to the right of the net and faces the left (the larger portion of net that he or she can see).
+
+Sometimes a setter refrains from raising the ball for a teammate to perform an attack and tries to play it directly onto the opponent's court. This movement is called a "dump".[30] This can only be performed when the setter is in the front row, otherwise it constitutes an illegal back court attack. The most common dumps are to 'throw' the ball behind the setter or in front of the setter to zones 2 and 4. More experienced setters toss the ball into the deep corners or spike the ball on the second hit.
+
+As with a set or an overhand pass, the setter/passer must be careful to touch the ball with both hands at the same time.[3] If one hand is noticeably late to touch the ball this could result in a less effective set, as well as the referee calling a 'double hit' and giving the point to the opposing team.
+
+The attack, also known as the spike, is usually the third contact a team makes with the ball.[3] The object of attacking is to handle the ball so that it lands on the opponent's court and cannot be defended.[3] A player makes a series of steps (the "approach"), jumps, and swings at the ball.
+
+Ideally, the contact with the ball is made at the apex of the hitter's jump. At the moment of contact, the hitter's arm is fully extended above their head and slightly forward, making the highest possible contact while maintaining the ability to deliver a powerful hit. The hitter uses arm swing, wrist snap, and a rapid forward contraction of the entire body to drive the ball.[3] A 'bounce' is a slang term for a very hard/loud spike that follows an almost straight trajectory steeply downward into the opponent's court and bounces very high into the air. A "kill" is the slang term for an attack that is not returned by the other team thus resulting in a point.
+
+Contemporary volleyball comprises a number of attacking techniques:
+
+Blocking refers to the actions taken by players standing at the net to stop or alter an opponent's attack.[3]
+
+A block that is aimed at completely stopping an attack, thus making the ball remain in the opponent's court, is called offensive. A well-executed offensive block is performed by jumping and reaching to penetrate with one's arms and hands over the net and into the opponent's area.[3] It requires anticipating the direction the ball will go once the attack takes place.[3] It may also require calculating the best footwork to executing the "perfect" block.
+
+The jump should be timed so as to intercept the ball's trajectory prior to it crossing over the plane of the net. Palms are held deflected downward roughly 45–60 degrees toward the interior of the opponents' court. A "roof" is a spectacular offensive block that redirects the power and speed of the attack straight down to the attacker's floor as if the attacker hit the ball into the underside of a peaked house roof.
+
+By contrast, it is called a defensive, or "soft" block if the goal is to control and deflect the hard-driven ball up so that it slows down and becomes easier to defend. A well-executed soft-block is performed by jumping and placing one's hands above the net with no penetration into the opponent's court and with the palms up and fingers pointing backwards.
+
+Blocking is also classified according to the number of players involved. Thus, one may speak of single (or solo), double, or triple block.[3]
+
+Successful blocking does not always result in a "roof" and many times does not even touch the ball. While it is obvious that a block was a success when the attacker is roofed, a block that consistently forces the attacker away from their 'power' or preferred attack into a more easily controlled shot by the defence is also a highly successful block.
+
+At the same time, the block position influences the positions where other defenders place themselves while opponent hitters are spiking.
+
+Digging is the ability to prevent the ball from touching one's court after a spike or attack, particularly a ball that is nearly touching the ground.[3] In many aspects, this skill is similar to passing, or bumping: overhand dig and bump are also used to distinguish between defensive actions taken with fingertips or with joined arms.[3] It varies from passing however in that is it a much more reflex based skill, especially at the higher levels. It is especially important while digging for players to stay on their toes; several players choose to employ a split step to make sure they're ready to move in any direction.
+
+Some specific techniques are more common in digging than in passing. A player may sometimes perform a "dive", i.e., throw their body in the air with a forward movement in an attempt to save the ball, and land on their chest. When the player also slides their hand under a ball that is almost touching the court, this is called a "pancake". The pancake is frequently used in indoor volleyball, but rarely if ever in beach volleyball because the uneven and yielding nature of the sand court limits the chances that the ball will make good, clean contact with the hand. When used correctly, it is one of the more spectacular defensive volleyball plays.
+
+Sometimes a player may also be forced to drop their body quickly to the floor to save the ball. In this situation, the player makes use of a specific rolling technique to minimize the chances of injuries.
+
+Volleyball is essentially a game of transition from one of the above skills to the next, with choreographed team movement between plays on the ball. These team movements are determined by the teams chosen serve receive system, offensive system, coverage system, and defensive system.
+
+The serve-receive system is the formation used by the receiving team to attempt to pass the ball to the designated setter. Systems can consist of 5 receivers, 4 receivers, 3 receivers, and in some cases 2 receivers. The most popular formation at higher levels is a 3 receiver formation consisting of two left sides and a libero receiving every rotation. This allows middles and right sides to become more specialized at hitting and blocking.
+
+Offensive systems are the formations used by the offence to attempt to ground the ball into the opposing court (or otherwise score points). Formations often include designated player positions with skill specialization (see Player specialization, below). Popular formations include the 4-2, 6-2, and 5-1 systems (see Formations, below). There are also several different attacking schemes teams can use to keep the opposing defence off balance.
+
+Coverage systems are the formations used by the offence to protect their court in the case of a blocked attack. Executed by the 5 offensive players not directly attacking the ball, players move to assigned positions around the attacker to dig up any ball that deflects off the block back into their own court. Popular formations include the 2-3 system and the 1-2-2 system. In lieu of a system, some teams just use a random coverage with the players nearest the hitter.
+
+Defensive systems are the formations used by the defence to protect against the ball being grounded into their court by the opposing team. The system will outline which players are responsible for which areas of the court depending on where the opposing team is attacking from. Popular systems include the 6-Up, 6-Back-Deep, and 6-Back-Slide defence. There are also several different blocking schemes teams can employ to disrupt the opposing teams' offence.
+
+When one player is ready to serve, some teams will line up their other five players in a screen to obscure the view of the receiving team. This action is only illegal if the server makes use of the screen, so the call is made at the referee's discretion as to the impact the screen made on the receiving team's ability to pass the ball. The most common style of screening involves a W formation designed to take up as much horizontal space as possible.
+
+There are five positions filled on every volleyball team at the elite level. Setter, Outside Hitter/Left Side Hitter, Middle Hitter, Opposite Hitter/Right Side Hitter and Libero/Defensive Specialist. Each of these positions plays a specific, key role in winning a volleyball match.
+
+At some levels where substitutions are unlimited, teams will make use of a Defensive Specialist in place of or in addition to a Libero. This position does not have unique rules like the libero position, instead, these players are used to substitute out a poor back row defender using regular substitution rules. A defensive specialist is often used if you have a particularly poor back court defender in right side or left side, but your team is already using a libero to take out your middles. Most often, the situation involves a team using a right side player with a big block who must be subbed out in the back row because they aren't able to effectively play backcourt defence. Similarly, teams might use a Serving Specialist to sub out a poor server.
+
+The three standard volleyball formations are known as "4–2", "6–2" and "5–1", which refers to the number of hitters and setters respectively. 4–2 is a basic formation used only in beginners' play, while 5–1 is by far the most common formation in high-level play.
+
+The 4–2 formation has four hitters and two setters. The setters usually set from the middle front or right front position. The team will, therefore, have two front-row attackers at all times. In the international 4–2, the setters set from the right front position. The international 4–2 translates more easily into other forms of offence.
+
+The setters line up opposite each other in the rotation. The typical lineup has two outside hitters. By aligning like positions opposite themselves in the rotation, there will always be one of each position in the front and back rows. After service, the players in the front row move into their assigned positions, so that the setter is always in the middle front. Alternatively, the setter moves into the right front and has both a middle and an outside attacker; the disadvantage here lies in the lack of an offside hitter, allowing one of the other team's blockers to "cheat in" on a middle block.
+
+The clear disadvantage to this offensive formation is that there are only two attackers, leaving a team with fewer offensive weapons.
+
+Another aspect is to see the setter as an attacking force, albeit a weakened force, because when the setter is in the frontcourt they are able to 'tip' or 'dump', so when the ball is close to the net on the second touch, the setter may opt to hit the ball over with one hand. This means that the blocker who would otherwise not have to block the setter is engaged and may allow one of the hitters to have an easier attack.
+
+In the 6–2 formation, a player always comes forward from the back row to set. The three front row players are all in attacking positions. Thus, all six players act as hitters at one time or another, while two can act as setters. So the 6–2 formation is actually a 4–2 system, but the back-row setter penetrates to set.
+
+The 6–2 lineup thus requires two setters, who line up opposite to each other in the rotation. In addition to the setters, a typical lineup will have two middle hitters and two outside hitters. By aligning like positions opposite themselves in the rotation, there will always be one of each position in the front and back rows. After service, the players in the front row move into their assigned positions.
+
+The advantage of the 6–2 is that there are always three front-row hitters available, maximizing the offensive possibilities. However, not only does the 6–2 require a team to possess two people capable of performing the highly specialized role of setter, it also requires both of those players to be effective offensive hitters when not in the setter position. At the international level, only the Cuban National Women's Team employs this kind of formation. It is also used by NCAA teams in Division III men's play and women's play in all divisions, partially due to the variant rules used which allow more substitutions per set than the 6 allowed in the standard rules—12 in matches involving two Division III men's teams[31] and 15 for all women's play.[32]
+
+The 5–1 formation has only one player who assumes setting responsibilities regardless of their position in the rotation. The team will, therefore, have three front-row attackers when the setter is in the back row and only two when the setter is in the front row, for a total of five possible attackers.
+
+The player opposite the setter in a 5–1 rotation is called the opposite hitter. In general, opposite hitters do not pass; they stand behind their teammates when the opponent is serving. The opposite hitter may be used as a third attack option (back-row attack) when the setter is in the front row: this is the normal option used to increase the attack capabilities of modern volleyball teams. Normally the opposite hitter is the most technically skilled hitter of the team. Back-row attacks generally come from the back-right position, known as zone 1, but are increasingly performed from back-centre in high-level play.
+
+The big advantage of this system is that the setter always has 3 hitters to vary sets with. If the setter does this well, the opponent's middle blocker may not have enough time to block with the outside blocker, increasing the chance for the attacking team to make a point.
+
+There is another advantage, the same as that of a 4–2 formation: when the setter is a front-row player, he or she is allowed to jump and "dump" the ball onto the opponent's side. This too can confuse the opponent's blocking players: the setter can jump and dump or can set to one of the hitters. A good setter knows this and thus won't only jump to dump or to set for a quick hit, but when setting outside as well to confuse the opponent.
+
+The 5–1 offence is actually a mix of 6–2 and 4–2: when the setter is in the front row, the offense looks like a 4–2; when the setter is in the back row, the offense looks like a 6–2.
+
+In 2017, a new volleyball union was formed in response to dissatisfaction with the organization and structure of professional beach volleyball tournaments.[33] The union is named the International Beach Volleyball Players Association, and it consists of almost 100 professional players.[33] IBVPA claims its goal is to help athletes and provide them with the means to enjoy playing volleyball by improving the way the sport is run.[33]
+
+Another controversy within the sport is the issue of the inclusion of transgender players.[34] With transgender athletes such as Tifanny Abreu joining professional volleyball teams alongside other non-transgender teammates, many professionals, sports analysts, and fans of volleyball are either expressing concerns about the legitimacy and fairness of having transgender players on a team or expressing support for the transgender people's efforts.[34]
+
+
+
+There are many variations on the basic rules of volleyball. By far the most popular of these is beach volleyball, which is played on sand with two people per team, and rivals the main sport in popularity.
+
+Some games related to volleyball include:

en/6034.html.txt

@@ -0,0 +1,163 @@
+
+
+Volleyball is a team sport in which two teams of six players are separated by a net. Each team tries to score points by grounding a ball on the other team's court under organized rules.[1] It has been a part of the official program of the Summer Olympic Games since Tokyo 1964.
+
+The complete set of rules is extensive,[2] but play essentially proceeds as follows: a player on one of the teams begins a 'rally' by serving the ball (tossing or releasing it and then hitting it with a hand or arm), from behind the back boundary line of the court, over the net, and into the receiving team's court.[3] The receiving team must not let the ball be grounded within their court. The team may touch the ball up to 3 times, but individual players may not touch the ball twice consecutively.[3] Typically, the first two touches are used to set up for an attack, an attempt to direct the ball back over the net in such a way that the serving team is unable to prevent it from being grounded in their court.
+
+The rally continues, with each team allowed as many as three consecutive touches, until either (1): a team makes a kill, grounding the ball on the opponent's court and winning the rally; or (2): a team commits a fault and loses the rally. The team that wins the rally is awarded a point and serves the ball to start the next rally. A few of the most common faults include:
+
+The ball is usually played with the hands or arms, but players can legally strike or push (short contact) the ball with any part of the body.
+
+A number of consistent techniques have evolved in volleyball, including spiking and blocking (because these plays are made above the top of the net, the vertical jump is an athletic skill emphasized in the sport) as well as passing, setting, and specialized player positions and offensive and defensive structures.
+
+In the winter of 1895,[4] in Holyoke, Massachusetts (United States), William G. Morgan, a YMCA physical education director, created a new game called Mintonette, a name derived from the game of badminton,[5] as a pastime to be played (preferably) indoors and by any number of players. The game took some of its characteristics from other sports such as tennis and handball.[6] Another indoor sport, basketball, was catching on in the area, having been invented just ten miles (sixteen kilometres) away in the city of Springfield, Massachusetts, only four years before. Mintonette was designed to be an indoor sport, less rough than basketball, for older members of the YMCA, while still requiring a bit of athletic effort.
+
+The first rules, written down by William G Morgan, called for a net 6 ft 6 in (1.98 m) high, a 25 ft × 50 ft (7.6 m × 15.2 m) court, and any number of players. A match was composed of nine innings with three serves for each team in each inning, and no limit to the number of ball contacts for each team before sending the ball to the opponents' court. In case of a serving error, a second try was allowed. Hitting the ball into the net was considered a foul (with loss of the point or a side-out)—except in the case of the first-try serve.
+
+After an observer, Alfred Halstead, noticed the volleying nature of the game at its first exhibition match in 1896, played at the International YMCA Training School (now called Springfield College), the game quickly became known as volleyball (it was originally spelled as two words: "volley ball"). Volleyball rules were slightly modified by the International YMCA Training School and the game spread around the country to various YMCAs.[7][8]
+
+The first official ball used in volleyball is disputed; some sources say Spalding created the first official ball in 1896, while others claim it was created in 1900.[9][10][11] The rules evolved over time: in 1916, in the Philippines, the skill and power of the set and spike had been introduced, and four years later a "three hits" rule and a rule against hitting from the back row were established. In 1917, the game was changed from requiring 21 points to win to a smaller 15 points to win. In 1919, about 16,000 volleyballs were distributed by the American Expeditionary Forces to their troops and allies, which sparked the growth of volleyball in new countries.[9]
+
+The first country outside the United States to adopt volleyball was Canada in 1900.[9] An international federation, the Fédération Internationale de Volleyball (FIVB), was founded in 1947, and the first World Championships were held in 1949 for men and 1952 for women.[12] The sport is now popular in Brazil, in Europe (where especially Italy, the Netherlands, and countries from Eastern Europe have been major forces since the late 1980s), in Russia, and in other countries including China and the rest of Asia, as well as in the United States.[7][8][12]
+
+Beach volleyball, a variation of the game played on sand and with only two players per team, became a FIVB-endorsed variation in 1987 and was added to the Olympic program at the 1996 Summer Olympics.[9][12] Volleyball is also a sport at the Paralympics managed by the World Organization Volleyball for Disabled.
+
+Nudists were early adopters of the game with regular organized play in clubs as early as the late 1920s.[13][14] By the 1960s, a volleyball court had become standard in almost all nudist/naturist clubs.[15]
+
+Volleyball has been part of the Summer Olympics program for both men and women consistently since 1964.
+
+A volleyball court is 9 m × 18 m (29.5 ft × 59.1 ft), divided into equal square halves by a net with a width of one meter (39.4 in).[16] The top of the net is 2.43 m (7 ft 11 11⁄16 in) above the center of the court for men's competition, and 2.24 m (7 ft 4 3⁄16 in) for women's competition, varied for veterans and junior competitions.[3]
+
+The minimum height clearance for indoor volleyball courts is 7 m (23.0 ft), although a clearance of 8 m (26.2 ft) is recommended.[16]
+
+A line 3 m (9.8 ft) from and parallel to the net is considered the "attack line". This "3 meter" (or "10-foot") line divides the court into "back row" and "front row" areas (also back court and front court).[16] These are in turn divided into 3 areas each: these are numbered as follows, starting from area "1", which is the position of the serving player:
+
+After a team gains the serve (also known as siding out), its members must rotate in a clockwise direction, with the player previously in area "2" moving to area "1" and so on, with the player from area "1" moving to area "6".[3] Each player rotates only one time after the team gains possession of the service; the next time each player rotates will be after the other team wins possession of the ball and loses the point.[16]
+
+The team courts are surrounded by an area called the free zone which is a minimum of 3 meters wide and which the players may enter and play within after the service of the ball.[17] All lines denoting the boundaries of the team court and the attack zone are drawn or painted within the dimensions of the area and are therefore a part of the court or zone. If a ball comes in contact with the line, the ball is considered to be "in". An antenna is placed on each side of the net perpendicular to the sideline and is a vertical extension of the side boundary of the court. A ball passing over the net must pass completely between the antennae (or their theoretical extensions to the ceiling) without contacting them.[3]
+
+FIVB regulations state that the ball must be spherical, made of leather or synthetic leather, have a circumference of 65–67 cm, a weight of 260–280 g and an inside pressure of 0.30–0.325 kg/cm2.[18] Other governing bodies have similar regulations.
+
+Each team consists of six players.[16] To get play started, a team is chosen to serve by coin toss. A player from the serving team throws the ball into the air and attempts to hit the ball so it passes over the net on a course such that it will land in the opposing team's court (the serve).[16] The opposing team must use a combination of no more than three contacts with the volleyball to return the ball to the opponent's side of the net.[16] These contacts usually consist first of the bump or pass so that the ball's trajectory is aimed towards the player designated as the setter; second of the set (usually an over-hand pass using wrists to push finger-tips at the ball) by the setter so that the ball's trajectory is aimed towards a spot where one of the players designated as an attacker can hit it, and third by the attacker who spikes (jumping, raising one arm above the head and hitting the ball so it will move quickly down to the ground on the opponent's court) to return the ball over the net.[3] The team with possession of the ball that is trying to attack the ball as described is said to be on offence.
+
+The team on defence attempts to prevent the attacker from directing the ball into their court: players at the net jump and reach above the top (and if possible, across the plane) of the net to block the attacked ball.[3] If the ball is hit around, above, or through the block, the defensive players arranged in the rest of the court attempt to control the ball with a dig (usually a fore-arm pass of a hard-driven ball). After a successful dig, the team transitions to offence.
+
+The game continues in this manner, rallying back and forth until the ball touches the court within the boundaries or until an error is made.[16] The most frequent errors that are made are either to fail to return the ball over the net within the allowed three touches, or to cause the ball to land outside the court.[16] A ball is "in" if any part of it touches the inside of a team's court or a sideline or end-line, and a strong spike may compress the ball enough when it lands that a ball which at first appears to be going out may actually be in. Players may travel well outside the court to play a ball that has gone over a sideline or end-line in the air.
+
+Other common errors include a player touching the ball twice in succession, a player "catching" the ball, a player touching the net while attempting to play the ball, or a player penetrating under the net into the opponent's court. There are a large number of other errors specified in the rules, although most of them are infrequent occurrences. These errors include back-row or libero players spiking the ball or blocking (back-row players may spike the ball if they jump from behind the attack line), players not being in the correct position when the ball is served, attacking the serve in the frontcourt and above the height of the net, using another player as a source of support to reach the ball, stepping over the back boundary line when serving, taking more than 8 seconds to serve,[19] or playing the ball when it is above the opponent's court.
+
+A point is scored when the ball contacts the floor within the court boundaries or when an error is made: when the ball strikes one team's side of the court, the other team gains a point; and when an error is made, the team that did not make the error is awarded a point, in either case paying no regard to whether they served the ball or not. If any part of the ball hits the line, the ball is counted as in the court. The team that won the point serves for the next point. If the team that won the point served in the previous point, the same player serves again. If the team that won the point did not serve the previous point, the players of the team acquiring the serve rotate their position on the court in a clockwise manner. The game continues, with the first team to score 25 points by a two-point margin awarded the set. Matches are best-of-five sets and the fifth set, if necessary, is usually played to 15 points. (Scoring differs between leagues, tournaments, and levels; high schools sometimes play best-of-three to 25; in the NCAA matches are played best-of-five to 25 as of the 2008 season.)[20]
+
+Before 1999, points could be scored only when a team had the serve (side-out scoring) and all sets went up to only 15 points. The FIVB changed the rules in 1999 (with the changes being compulsory in 2000) to use the current scoring system (formerly known as rally point system), primarily to make the length of the match more predictable and to make the game more spectator- and television-friendly.
+
+The final year of side-out scoring at the NCAA Division I Women's Volleyball Championship was 2000. Rally point scoring debuted in 2001,[21] and games were played to 30 points through 2007. For the 2008 season, games were renamed "sets" and reduced to 25 points to win. Most high schools in the U.S. changed to rally scoring in 2003,[22][23][24] and several states implemented it the previous year on an experimental basis.[25]
+
+The libero player was introduced internationally in 1998,[26] and made its debut for NCAA competition in 2002.[27] The libero is a player specialized in defensive skills: the libero must wear a contrasting jersey color from their teammates and cannot block or attack the ball when it is entirely above net height. When the ball is not in play, the libero can replace any back-row player, without prior notice to the officials. This replacement does not count against the substitution limit each team is allowed per set, although the libero may be replaced only by the player whom he or she replaced. Most U.S. high schools added the libero position from 2003 to 2005.[23][28]
+
+The modern-day libero often takes on the role of a second setter. When the setter digs the ball, the libero is typically responsible for the second ball and sets to the front row attacker. The libero may function as a setter only under certain restrictions. To make an overhand set, the libero must be standing behind (and not stepping on) the 3-meter line; otherwise, the ball cannot be attacked above the net in front of the 3-meter line. An underhand pass is allowed from any part of the court.
+
+The libero is, generally, the most skilled defensive player on the team. There is also a libero tracking sheet, where the referees or officiating team must keep track of whom the libero subs in and out for. Under FIVB rules, two liberos are designated at the beginning of the play, only one of whom can be on the court at any time.
+
+Furthermore, a libero is not allowed to serve, according to international rules. NCAA rules for both men and women differ on this point; a 2004 rule change allows the libero to serve, but only in a specific rotation. That is, the libero can only serve for one person, not for all of the people for whom he or she goes in. That rule change was also applied to high school and junior high play soon after.
+
+Other rule changes enacted in 2000 include allowing serves in which the ball touches the net, as long as it goes over the net into the opponents' court. Also, the service area was expanded to allow players to serve from anywhere behind the end line but still within the theoretical extension of the sidelines. Other changes were made to lighten up calls on faults for carries and double-touches, such as allowing multiple contacts by a single player ("double-hits") on a team's first contact provided that they are a part of a single play on the ball.
+
+In 2008, the NCAA changed the minimum number of points needed to win any of the first four sets from 30 to 25 for women's volleyball (men's volleyball remained at 30 for another three years, switching to 25 in 2011.) If a fifth (deciding) set is reached, the minimum required score remains at 15. In addition, the word "game" is now referred to as "set".[20]
+
+The Official Volleyball Rules are prepared and updated every few years by the FIVB's Rules of the Game and Refereeing Commission.[29] The latest edition is usually available on the FIVB's website.[2]
+
+Competitive teams master six basic skills: serve, pass, set, attack, block and dig.[3] Each of these skills comprises a number of specific techniques that have been introduced over the years and are now considered standard practice in high-level volleyball.
+
+A player stands behind the inline and serves the ball, in an attempt to drive it into the opponent's court. The main objective is to make it land inside the court; it is also desirable to set the ball's direction, speed and acceleration so that it becomes difficult for the receiver to handle it properly.[3] A serve is called an "ace" when the ball lands directly onto the court or travels outside the court after being touched by an opponent; when the only player on the server's team to touch the ball is the server.
+
+In contemporary volleyball, many types of serves are employed:
+
+Also called reception, the pass is the attempt by a team to properly handle the opponent's serve or any form of attack. Proper handling includes not only preventing the ball from touching the court but also making it reach the position where the setter is standing quickly and precisely.[3]
+
+The skill of passing involves fundamentally two specific techniques: underarm pass, or bump, where the ball touches the inside part of the joined forearms or platform, at waistline; and overhand pass, where it is handled with the fingertips, like a set, above the head.[3] Either are acceptable in professional and beach volleyball; however, there are much tighter regulations on the overhand pass in beach volleyball. When a player passes a ball to their setter, it's ideal that the ball does not have a lot of spin to make it easier for the setter.
+
+The set is usually the second contact that a team makes with the ball.[3] The main goal of setting is to put the ball in the air in such a way that it can be driven by an attack into the opponent's court.[3] The setter coordinates the offensive movements of a team, and is the player who ultimately decides which player will actually attack the ball.
+
+As with passing, one may distinguish between an overhand and a bump set. Since the former allows for more control over the speed and direction of the ball, the bump is used only when the ball is so low it cannot be properly handled with fingertips, or in beach volleyball where rules regulating overhand setting are more stringent. In the case of a set, one also speaks of a front or back set, meaning whether the ball is passed in the direction the setter is facing or behind the setter. There is also a jump set that is used when the ball is too close to the net. In this case, the setter usually jumps off their right foot straight up to avoid going into the net. The setter usually stands about ⅔ of the way from the left to the right of the net and faces the left (the larger portion of net that he or she can see).
+
+Sometimes a setter refrains from raising the ball for a teammate to perform an attack and tries to play it directly onto the opponent's court. This movement is called a "dump".[30] This can only be performed when the setter is in the front row, otherwise it constitutes an illegal back court attack. The most common dumps are to 'throw' the ball behind the setter or in front of the setter to zones 2 and 4. More experienced setters toss the ball into the deep corners or spike the ball on the second hit.
+
+As with a set or an overhand pass, the setter/passer must be careful to touch the ball with both hands at the same time.[3] If one hand is noticeably late to touch the ball this could result in a less effective set, as well as the referee calling a 'double hit' and giving the point to the opposing team.
+
+The attack, also known as the spike, is usually the third contact a team makes with the ball.[3] The object of attacking is to handle the ball so that it lands on the opponent's court and cannot be defended.[3] A player makes a series of steps (the "approach"), jumps, and swings at the ball.
+
+Ideally, the contact with the ball is made at the apex of the hitter's jump. At the moment of contact, the hitter's arm is fully extended above their head and slightly forward, making the highest possible contact while maintaining the ability to deliver a powerful hit. The hitter uses arm swing, wrist snap, and a rapid forward contraction of the entire body to drive the ball.[3] A 'bounce' is a slang term for a very hard/loud spike that follows an almost straight trajectory steeply downward into the opponent's court and bounces very high into the air. A "kill" is the slang term for an attack that is not returned by the other team thus resulting in a point.
+
+Contemporary volleyball comprises a number of attacking techniques:
+
+Blocking refers to the actions taken by players standing at the net to stop or alter an opponent's attack.[3]
+
+A block that is aimed at completely stopping an attack, thus making the ball remain in the opponent's court, is called offensive. A well-executed offensive block is performed by jumping and reaching to penetrate with one's arms and hands over the net and into the opponent's area.[3] It requires anticipating the direction the ball will go once the attack takes place.[3] It may also require calculating the best footwork to executing the "perfect" block.
+
+The jump should be timed so as to intercept the ball's trajectory prior to it crossing over the plane of the net. Palms are held deflected downward roughly 45–60 degrees toward the interior of the opponents' court. A "roof" is a spectacular offensive block that redirects the power and speed of the attack straight down to the attacker's floor as if the attacker hit the ball into the underside of a peaked house roof.
+
+By contrast, it is called a defensive, or "soft" block if the goal is to control and deflect the hard-driven ball up so that it slows down and becomes easier to defend. A well-executed soft-block is performed by jumping and placing one's hands above the net with no penetration into the opponent's court and with the palms up and fingers pointing backwards.
+
+Blocking is also classified according to the number of players involved. Thus, one may speak of single (or solo), double, or triple block.[3]
+
+Successful blocking does not always result in a "roof" and many times does not even touch the ball. While it is obvious that a block was a success when the attacker is roofed, a block that consistently forces the attacker away from their 'power' or preferred attack into a more easily controlled shot by the defence is also a highly successful block.
+
+At the same time, the block position influences the positions where other defenders place themselves while opponent hitters are spiking.
+
+Digging is the ability to prevent the ball from touching one's court after a spike or attack, particularly a ball that is nearly touching the ground.[3] In many aspects, this skill is similar to passing, or bumping: overhand dig and bump are also used to distinguish between defensive actions taken with fingertips or with joined arms.[3] It varies from passing however in that is it a much more reflex based skill, especially at the higher levels. It is especially important while digging for players to stay on their toes; several players choose to employ a split step to make sure they're ready to move in any direction.
+
+Some specific techniques are more common in digging than in passing. A player may sometimes perform a "dive", i.e., throw their body in the air with a forward movement in an attempt to save the ball, and land on their chest. When the player also slides their hand under a ball that is almost touching the court, this is called a "pancake". The pancake is frequently used in indoor volleyball, but rarely if ever in beach volleyball because the uneven and yielding nature of the sand court limits the chances that the ball will make good, clean contact with the hand. When used correctly, it is one of the more spectacular defensive volleyball plays.
+
+Sometimes a player may also be forced to drop their body quickly to the floor to save the ball. In this situation, the player makes use of a specific rolling technique to minimize the chances of injuries.
+
+Volleyball is essentially a game of transition from one of the above skills to the next, with choreographed team movement between plays on the ball. These team movements are determined by the teams chosen serve receive system, offensive system, coverage system, and defensive system.
+
+The serve-receive system is the formation used by the receiving team to attempt to pass the ball to the designated setter. Systems can consist of 5 receivers, 4 receivers, 3 receivers, and in some cases 2 receivers. The most popular formation at higher levels is a 3 receiver formation consisting of two left sides and a libero receiving every rotation. This allows middles and right sides to become more specialized at hitting and blocking.
+
+Offensive systems are the formations used by the offence to attempt to ground the ball into the opposing court (or otherwise score points). Formations often include designated player positions with skill specialization (see Player specialization, below). Popular formations include the 4-2, 6-2, and 5-1 systems (see Formations, below). There are also several different attacking schemes teams can use to keep the opposing defence off balance.
+
+Coverage systems are the formations used by the offence to protect their court in the case of a blocked attack. Executed by the 5 offensive players not directly attacking the ball, players move to assigned positions around the attacker to dig up any ball that deflects off the block back into their own court. Popular formations include the 2-3 system and the 1-2-2 system. In lieu of a system, some teams just use a random coverage with the players nearest the hitter.
+
+Defensive systems are the formations used by the defence to protect against the ball being grounded into their court by the opposing team. The system will outline which players are responsible for which areas of the court depending on where the opposing team is attacking from. Popular systems include the 6-Up, 6-Back-Deep, and 6-Back-Slide defence. There are also several different blocking schemes teams can employ to disrupt the opposing teams' offence.
+
+When one player is ready to serve, some teams will line up their other five players in a screen to obscure the view of the receiving team. This action is only illegal if the server makes use of the screen, so the call is made at the referee's discretion as to the impact the screen made on the receiving team's ability to pass the ball. The most common style of screening involves a W formation designed to take up as much horizontal space as possible.
+
+There are five positions filled on every volleyball team at the elite level. Setter, Outside Hitter/Left Side Hitter, Middle Hitter, Opposite Hitter/Right Side Hitter and Libero/Defensive Specialist. Each of these positions plays a specific, key role in winning a volleyball match.
+
+At some levels where substitutions are unlimited, teams will make use of a Defensive Specialist in place of or in addition to a Libero. This position does not have unique rules like the libero position, instead, these players are used to substitute out a poor back row defender using regular substitution rules. A defensive specialist is often used if you have a particularly poor back court defender in right side or left side, but your team is already using a libero to take out your middles. Most often, the situation involves a team using a right side player with a big block who must be subbed out in the back row because they aren't able to effectively play backcourt defence. Similarly, teams might use a Serving Specialist to sub out a poor server.
+
+The three standard volleyball formations are known as "4–2", "6–2" and "5–1", which refers to the number of hitters and setters respectively. 4–2 is a basic formation used only in beginners' play, while 5–1 is by far the most common formation in high-level play.
+
+The 4–2 formation has four hitters and two setters. The setters usually set from the middle front or right front position. The team will, therefore, have two front-row attackers at all times. In the international 4–2, the setters set from the right front position. The international 4–2 translates more easily into other forms of offence.
+
+The setters line up opposite each other in the rotation. The typical lineup has two outside hitters. By aligning like positions opposite themselves in the rotation, there will always be one of each position in the front and back rows. After service, the players in the front row move into their assigned positions, so that the setter is always in the middle front. Alternatively, the setter moves into the right front and has both a middle and an outside attacker; the disadvantage here lies in the lack of an offside hitter, allowing one of the other team's blockers to "cheat in" on a middle block.
+
+The clear disadvantage to this offensive formation is that there are only two attackers, leaving a team with fewer offensive weapons.
+
+Another aspect is to see the setter as an attacking force, albeit a weakened force, because when the setter is in the frontcourt they are able to 'tip' or 'dump', so when the ball is close to the net on the second touch, the setter may opt to hit the ball over with one hand. This means that the blocker who would otherwise not have to block the setter is engaged and may allow one of the hitters to have an easier attack.
+
+In the 6–2 formation, a player always comes forward from the back row to set. The three front row players are all in attacking positions. Thus, all six players act as hitters at one time or another, while two can act as setters. So the 6–2 formation is actually a 4–2 system, but the back-row setter penetrates to set.
+
+The 6–2 lineup thus requires two setters, who line up opposite to each other in the rotation. In addition to the setters, a typical lineup will have two middle hitters and two outside hitters. By aligning like positions opposite themselves in the rotation, there will always be one of each position in the front and back rows. After service, the players in the front row move into their assigned positions.
+
+The advantage of the 6–2 is that there are always three front-row hitters available, maximizing the offensive possibilities. However, not only does the 6–2 require a team to possess two people capable of performing the highly specialized role of setter, it also requires both of those players to be effective offensive hitters when not in the setter position. At the international level, only the Cuban National Women's Team employs this kind of formation. It is also used by NCAA teams in Division III men's play and women's play in all divisions, partially due to the variant rules used which allow more substitutions per set than the 6 allowed in the standard rules—12 in matches involving two Division III men's teams[31] and 15 for all women's play.[32]
+
+The 5–1 formation has only one player who assumes setting responsibilities regardless of their position in the rotation. The team will, therefore, have three front-row attackers when the setter is in the back row and only two when the setter is in the front row, for a total of five possible attackers.
+
+The player opposite the setter in a 5–1 rotation is called the opposite hitter. In general, opposite hitters do not pass; they stand behind their teammates when the opponent is serving. The opposite hitter may be used as a third attack option (back-row attack) when the setter is in the front row: this is the normal option used to increase the attack capabilities of modern volleyball teams. Normally the opposite hitter is the most technically skilled hitter of the team. Back-row attacks generally come from the back-right position, known as zone 1, but are increasingly performed from back-centre in high-level play.
+
+The big advantage of this system is that the setter always has 3 hitters to vary sets with. If the setter does this well, the opponent's middle blocker may not have enough time to block with the outside blocker, increasing the chance for the attacking team to make a point.
+
+There is another advantage, the same as that of a 4–2 formation: when the setter is a front-row player, he or she is allowed to jump and "dump" the ball onto the opponent's side. This too can confuse the opponent's blocking players: the setter can jump and dump or can set to one of the hitters. A good setter knows this and thus won't only jump to dump or to set for a quick hit, but when setting outside as well to confuse the opponent.
+
+The 5–1 offence is actually a mix of 6–2 and 4–2: when the setter is in the front row, the offense looks like a 4–2; when the setter is in the back row, the offense looks like a 6–2.
+
+In 2017, a new volleyball union was formed in response to dissatisfaction with the organization and structure of professional beach volleyball tournaments.[33] The union is named the International Beach Volleyball Players Association, and it consists of almost 100 professional players.[33] IBVPA claims its goal is to help athletes and provide them with the means to enjoy playing volleyball by improving the way the sport is run.[33]
+
+Another controversy within the sport is the issue of the inclusion of transgender players.[34] With transgender athletes such as Tifanny Abreu joining professional volleyball teams alongside other non-transgender teammates, many professionals, sports analysts, and fans of volleyball are either expressing concerns about the legitimacy and fairness of having transgender players on a team or expressing support for the transgender people's efforts.[34]
+
+
+
+There are many variations on the basic rules of volleyball. By far the most popular of these is beach volleyball, which is played on sand with two people per team, and rivals the main sport in popularity.
+
+Some games related to volleyball include:

en/6035.html.txt

@@ -0,0 +1,163 @@
+
+
+Volleyball is a team sport in which two teams of six players are separated by a net. Each team tries to score points by grounding a ball on the other team's court under organized rules.[1] It has been a part of the official program of the Summer Olympic Games since Tokyo 1964.
+
+The complete set of rules is extensive,[2] but play essentially proceeds as follows: a player on one of the teams begins a 'rally' by serving the ball (tossing or releasing it and then hitting it with a hand or arm), from behind the back boundary line of the court, over the net, and into the receiving team's court.[3] The receiving team must not let the ball be grounded within their court. The team may touch the ball up to 3 times, but individual players may not touch the ball twice consecutively.[3] Typically, the first two touches are used to set up for an attack, an attempt to direct the ball back over the net in such a way that the serving team is unable to prevent it from being grounded in their court.
+
+The rally continues, with each team allowed as many as three consecutive touches, until either (1): a team makes a kill, grounding the ball on the opponent's court and winning the rally; or (2): a team commits a fault and loses the rally. The team that wins the rally is awarded a point and serves the ball to start the next rally. A few of the most common faults include:
+
+The ball is usually played with the hands or arms, but players can legally strike or push (short contact) the ball with any part of the body.
+
+A number of consistent techniques have evolved in volleyball, including spiking and blocking (because these plays are made above the top of the net, the vertical jump is an athletic skill emphasized in the sport) as well as passing, setting, and specialized player positions and offensive and defensive structures.
+
+In the winter of 1895,[4] in Holyoke, Massachusetts (United States), William G. Morgan, a YMCA physical education director, created a new game called Mintonette, a name derived from the game of badminton,[5] as a pastime to be played (preferably) indoors and by any number of players. The game took some of its characteristics from other sports such as tennis and handball.[6] Another indoor sport, basketball, was catching on in the area, having been invented just ten miles (sixteen kilometres) away in the city of Springfield, Massachusetts, only four years before. Mintonette was designed to be an indoor sport, less rough than basketball, for older members of the YMCA, while still requiring a bit of athletic effort.
+
+The first rules, written down by William G Morgan, called for a net 6 ft 6 in (1.98 m) high, a 25 ft × 50 ft (7.6 m × 15.2 m) court, and any number of players. A match was composed of nine innings with three serves for each team in each inning, and no limit to the number of ball contacts for each team before sending the ball to the opponents' court. In case of a serving error, a second try was allowed. Hitting the ball into the net was considered a foul (with loss of the point or a side-out)—except in the case of the first-try serve.
+
+After an observer, Alfred Halstead, noticed the volleying nature of the game at its first exhibition match in 1896, played at the International YMCA Training School (now called Springfield College), the game quickly became known as volleyball (it was originally spelled as two words: "volley ball"). Volleyball rules were slightly modified by the International YMCA Training School and the game spread around the country to various YMCAs.[7][8]
+
+The first official ball used in volleyball is disputed; some sources say Spalding created the first official ball in 1896, while others claim it was created in 1900.[9][10][11] The rules evolved over time: in 1916, in the Philippines, the skill and power of the set and spike had been introduced, and four years later a "three hits" rule and a rule against hitting from the back row were established. In 1917, the game was changed from requiring 21 points to win to a smaller 15 points to win. In 1919, about 16,000 volleyballs were distributed by the American Expeditionary Forces to their troops and allies, which sparked the growth of volleyball in new countries.[9]
+
+The first country outside the United States to adopt volleyball was Canada in 1900.[9] An international federation, the Fédération Internationale de Volleyball (FIVB), was founded in 1947, and the first World Championships were held in 1949 for men and 1952 for women.[12] The sport is now popular in Brazil, in Europe (where especially Italy, the Netherlands, and countries from Eastern Europe have been major forces since the late 1980s), in Russia, and in other countries including China and the rest of Asia, as well as in the United States.[7][8][12]
+
+Beach volleyball, a variation of the game played on sand and with only two players per team, became a FIVB-endorsed variation in 1987 and was added to the Olympic program at the 1996 Summer Olympics.[9][12] Volleyball is also a sport at the Paralympics managed by the World Organization Volleyball for Disabled.
+
+Nudists were early adopters of the game with regular organized play in clubs as early as the late 1920s.[13][14] By the 1960s, a volleyball court had become standard in almost all nudist/naturist clubs.[15]
+
+Volleyball has been part of the Summer Olympics program for both men and women consistently since 1964.
+
+A volleyball court is 9 m × 18 m (29.5 ft × 59.1 ft), divided into equal square halves by a net with a width of one meter (39.4 in).[16] The top of the net is 2.43 m (7 ft 11 11⁄16 in) above the center of the court for men's competition, and 2.24 m (7 ft 4 3⁄16 in) for women's competition, varied for veterans and junior competitions.[3]
+
+The minimum height clearance for indoor volleyball courts is 7 m (23.0 ft), although a clearance of 8 m (26.2 ft) is recommended.[16]
+
+A line 3 m (9.8 ft) from and parallel to the net is considered the "attack line". This "3 meter" (or "10-foot") line divides the court into "back row" and "front row" areas (also back court and front court).[16] These are in turn divided into 3 areas each: these are numbered as follows, starting from area "1", which is the position of the serving player:
+
+After a team gains the serve (also known as siding out), its members must rotate in a clockwise direction, with the player previously in area "2" moving to area "1" and so on, with the player from area "1" moving to area "6".[3] Each player rotates only one time after the team gains possession of the service; the next time each player rotates will be after the other team wins possession of the ball and loses the point.[16]
+
+The team courts are surrounded by an area called the free zone which is a minimum of 3 meters wide and which the players may enter and play within after the service of the ball.[17] All lines denoting the boundaries of the team court and the attack zone are drawn or painted within the dimensions of the area and are therefore a part of the court or zone. If a ball comes in contact with the line, the ball is considered to be "in". An antenna is placed on each side of the net perpendicular to the sideline and is a vertical extension of the side boundary of the court. A ball passing over the net must pass completely between the antennae (or their theoretical extensions to the ceiling) without contacting them.[3]
+
+FIVB regulations state that the ball must be spherical, made of leather or synthetic leather, have a circumference of 65–67 cm, a weight of 260–280 g and an inside pressure of 0.30–0.325 kg/cm2.[18] Other governing bodies have similar regulations.
+
+Each team consists of six players.[16] To get play started, a team is chosen to serve by coin toss. A player from the serving team throws the ball into the air and attempts to hit the ball so it passes over the net on a course such that it will land in the opposing team's court (the serve).[16] The opposing team must use a combination of no more than three contacts with the volleyball to return the ball to the opponent's side of the net.[16] These contacts usually consist first of the bump or pass so that the ball's trajectory is aimed towards the player designated as the setter; second of the set (usually an over-hand pass using wrists to push finger-tips at the ball) by the setter so that the ball's trajectory is aimed towards a spot where one of the players designated as an attacker can hit it, and third by the attacker who spikes (jumping, raising one arm above the head and hitting the ball so it will move quickly down to the ground on the opponent's court) to return the ball over the net.[3] The team with possession of the ball that is trying to attack the ball as described is said to be on offence.
+
+The team on defence attempts to prevent the attacker from directing the ball into their court: players at the net jump and reach above the top (and if possible, across the plane) of the net to block the attacked ball.[3] If the ball is hit around, above, or through the block, the defensive players arranged in the rest of the court attempt to control the ball with a dig (usually a fore-arm pass of a hard-driven ball). After a successful dig, the team transitions to offence.
+
+The game continues in this manner, rallying back and forth until the ball touches the court within the boundaries or until an error is made.[16] The most frequent errors that are made are either to fail to return the ball over the net within the allowed three touches, or to cause the ball to land outside the court.[16] A ball is "in" if any part of it touches the inside of a team's court or a sideline or end-line, and a strong spike may compress the ball enough when it lands that a ball which at first appears to be going out may actually be in. Players may travel well outside the court to play a ball that has gone over a sideline or end-line in the air.
+
+Other common errors include a player touching the ball twice in succession, a player "catching" the ball, a player touching the net while attempting to play the ball, or a player penetrating under the net into the opponent's court. There are a large number of other errors specified in the rules, although most of them are infrequent occurrences. These errors include back-row or libero players spiking the ball or blocking (back-row players may spike the ball if they jump from behind the attack line), players not being in the correct position when the ball is served, attacking the serve in the frontcourt and above the height of the net, using another player as a source of support to reach the ball, stepping over the back boundary line when serving, taking more than 8 seconds to serve,[19] or playing the ball when it is above the opponent's court.
+
+A point is scored when the ball contacts the floor within the court boundaries or when an error is made: when the ball strikes one team's side of the court, the other team gains a point; and when an error is made, the team that did not make the error is awarded a point, in either case paying no regard to whether they served the ball or not. If any part of the ball hits the line, the ball is counted as in the court. The team that won the point serves for the next point. If the team that won the point served in the previous point, the same player serves again. If the team that won the point did not serve the previous point, the players of the team acquiring the serve rotate their position on the court in a clockwise manner. The game continues, with the first team to score 25 points by a two-point margin awarded the set. Matches are best-of-five sets and the fifth set, if necessary, is usually played to 15 points. (Scoring differs between leagues, tournaments, and levels; high schools sometimes play best-of-three to 25; in the NCAA matches are played best-of-five to 25 as of the 2008 season.)[20]
+
+Before 1999, points could be scored only when a team had the serve (side-out scoring) and all sets went up to only 15 points. The FIVB changed the rules in 1999 (with the changes being compulsory in 2000) to use the current scoring system (formerly known as rally point system), primarily to make the length of the match more predictable and to make the game more spectator- and television-friendly.
+
+The final year of side-out scoring at the NCAA Division I Women's Volleyball Championship was 2000. Rally point scoring debuted in 2001,[21] and games were played to 30 points through 2007. For the 2008 season, games were renamed "sets" and reduced to 25 points to win. Most high schools in the U.S. changed to rally scoring in 2003,[22][23][24] and several states implemented it the previous year on an experimental basis.[25]
+
+The libero player was introduced internationally in 1998,[26] and made its debut for NCAA competition in 2002.[27] The libero is a player specialized in defensive skills: the libero must wear a contrasting jersey color from their teammates and cannot block or attack the ball when it is entirely above net height. When the ball is not in play, the libero can replace any back-row player, without prior notice to the officials. This replacement does not count against the substitution limit each team is allowed per set, although the libero may be replaced only by the player whom he or she replaced. Most U.S. high schools added the libero position from 2003 to 2005.[23][28]
+
+The modern-day libero often takes on the role of a second setter. When the setter digs the ball, the libero is typically responsible for the second ball and sets to the front row attacker. The libero may function as a setter only under certain restrictions. To make an overhand set, the libero must be standing behind (and not stepping on) the 3-meter line; otherwise, the ball cannot be attacked above the net in front of the 3-meter line. An underhand pass is allowed from any part of the court.
+
+The libero is, generally, the most skilled defensive player on the team. There is also a libero tracking sheet, where the referees or officiating team must keep track of whom the libero subs in and out for. Under FIVB rules, two liberos are designated at the beginning of the play, only one of whom can be on the court at any time.
+
+Furthermore, a libero is not allowed to serve, according to international rules. NCAA rules for both men and women differ on this point; a 2004 rule change allows the libero to serve, but only in a specific rotation. That is, the libero can only serve for one person, not for all of the people for whom he or she goes in. That rule change was also applied to high school and junior high play soon after.
+
+Other rule changes enacted in 2000 include allowing serves in which the ball touches the net, as long as it goes over the net into the opponents' court. Also, the service area was expanded to allow players to serve from anywhere behind the end line but still within the theoretical extension of the sidelines. Other changes were made to lighten up calls on faults for carries and double-touches, such as allowing multiple contacts by a single player ("double-hits") on a team's first contact provided that they are a part of a single play on the ball.
+
+In 2008, the NCAA changed the minimum number of points needed to win any of the first four sets from 30 to 25 for women's volleyball (men's volleyball remained at 30 for another three years, switching to 25 in 2011.) If a fifth (deciding) set is reached, the minimum required score remains at 15. In addition, the word "game" is now referred to as "set".[20]
+
+The Official Volleyball Rules are prepared and updated every few years by the FIVB's Rules of the Game and Refereeing Commission.[29] The latest edition is usually available on the FIVB's website.[2]
+
+Competitive teams master six basic skills: serve, pass, set, attack, block and dig.[3] Each of these skills comprises a number of specific techniques that have been introduced over the years and are now considered standard practice in high-level volleyball.
+
+A player stands behind the inline and serves the ball, in an attempt to drive it into the opponent's court. The main objective is to make it land inside the court; it is also desirable to set the ball's direction, speed and acceleration so that it becomes difficult for the receiver to handle it properly.[3] A serve is called an "ace" when the ball lands directly onto the court or travels outside the court after being touched by an opponent; when the only player on the server's team to touch the ball is the server.
+
+In contemporary volleyball, many types of serves are employed:
+
+Also called reception, the pass is the attempt by a team to properly handle the opponent's serve or any form of attack. Proper handling includes not only preventing the ball from touching the court but also making it reach the position where the setter is standing quickly and precisely.[3]
+
+The skill of passing involves fundamentally two specific techniques: underarm pass, or bump, where the ball touches the inside part of the joined forearms or platform, at waistline; and overhand pass, where it is handled with the fingertips, like a set, above the head.[3] Either are acceptable in professional and beach volleyball; however, there are much tighter regulations on the overhand pass in beach volleyball. When a player passes a ball to their setter, it's ideal that the ball does not have a lot of spin to make it easier for the setter.
+
+The set is usually the second contact that a team makes with the ball.[3] The main goal of setting is to put the ball in the air in such a way that it can be driven by an attack into the opponent's court.[3] The setter coordinates the offensive movements of a team, and is the player who ultimately decides which player will actually attack the ball.
+
+As with passing, one may distinguish between an overhand and a bump set. Since the former allows for more control over the speed and direction of the ball, the bump is used only when the ball is so low it cannot be properly handled with fingertips, or in beach volleyball where rules regulating overhand setting are more stringent. In the case of a set, one also speaks of a front or back set, meaning whether the ball is passed in the direction the setter is facing or behind the setter. There is also a jump set that is used when the ball is too close to the net. In this case, the setter usually jumps off their right foot straight up to avoid going into the net. The setter usually stands about ⅔ of the way from the left to the right of the net and faces the left (the larger portion of net that he or she can see).
+
+Sometimes a setter refrains from raising the ball for a teammate to perform an attack and tries to play it directly onto the opponent's court. This movement is called a "dump".[30] This can only be performed when the setter is in the front row, otherwise it constitutes an illegal back court attack. The most common dumps are to 'throw' the ball behind the setter or in front of the setter to zones 2 and 4. More experienced setters toss the ball into the deep corners or spike the ball on the second hit.
+
+As with a set or an overhand pass, the setter/passer must be careful to touch the ball with both hands at the same time.[3] If one hand is noticeably late to touch the ball this could result in a less effective set, as well as the referee calling a 'double hit' and giving the point to the opposing team.
+
+The attack, also known as the spike, is usually the third contact a team makes with the ball.[3] The object of attacking is to handle the ball so that it lands on the opponent's court and cannot be defended.[3] A player makes a series of steps (the "approach"), jumps, and swings at the ball.
+
+Ideally, the contact with the ball is made at the apex of the hitter's jump. At the moment of contact, the hitter's arm is fully extended above their head and slightly forward, making the highest possible contact while maintaining the ability to deliver a powerful hit. The hitter uses arm swing, wrist snap, and a rapid forward contraction of the entire body to drive the ball.[3] A 'bounce' is a slang term for a very hard/loud spike that follows an almost straight trajectory steeply downward into the opponent's court and bounces very high into the air. A "kill" is the slang term for an attack that is not returned by the other team thus resulting in a point.
+
+Contemporary volleyball comprises a number of attacking techniques:
+
+Blocking refers to the actions taken by players standing at the net to stop or alter an opponent's attack.[3]
+
+A block that is aimed at completely stopping an attack, thus making the ball remain in the opponent's court, is called offensive. A well-executed offensive block is performed by jumping and reaching to penetrate with one's arms and hands over the net and into the opponent's area.[3] It requires anticipating the direction the ball will go once the attack takes place.[3] It may also require calculating the best footwork to executing the "perfect" block.
+
+The jump should be timed so as to intercept the ball's trajectory prior to it crossing over the plane of the net. Palms are held deflected downward roughly 45–60 degrees toward the interior of the opponents' court. A "roof" is a spectacular offensive block that redirects the power and speed of the attack straight down to the attacker's floor as if the attacker hit the ball into the underside of a peaked house roof.
+
+By contrast, it is called a defensive, or "soft" block if the goal is to control and deflect the hard-driven ball up so that it slows down and becomes easier to defend. A well-executed soft-block is performed by jumping and placing one's hands above the net with no penetration into the opponent's court and with the palms up and fingers pointing backwards.
+
+Blocking is also classified according to the number of players involved. Thus, one may speak of single (or solo), double, or triple block.[3]
+
+Successful blocking does not always result in a "roof" and many times does not even touch the ball. While it is obvious that a block was a success when the attacker is roofed, a block that consistently forces the attacker away from their 'power' or preferred attack into a more easily controlled shot by the defence is also a highly successful block.
+
+At the same time, the block position influences the positions where other defenders place themselves while opponent hitters are spiking.
+
+Digging is the ability to prevent the ball from touching one's court after a spike or attack, particularly a ball that is nearly touching the ground.[3] In many aspects, this skill is similar to passing, or bumping: overhand dig and bump are also used to distinguish between defensive actions taken with fingertips or with joined arms.[3] It varies from passing however in that is it a much more reflex based skill, especially at the higher levels. It is especially important while digging for players to stay on their toes; several players choose to employ a split step to make sure they're ready to move in any direction.
+
+Some specific techniques are more common in digging than in passing. A player may sometimes perform a "dive", i.e., throw their body in the air with a forward movement in an attempt to save the ball, and land on their chest. When the player also slides their hand under a ball that is almost touching the court, this is called a "pancake". The pancake is frequently used in indoor volleyball, but rarely if ever in beach volleyball because the uneven and yielding nature of the sand court limits the chances that the ball will make good, clean contact with the hand. When used correctly, it is one of the more spectacular defensive volleyball plays.
+
+Sometimes a player may also be forced to drop their body quickly to the floor to save the ball. In this situation, the player makes use of a specific rolling technique to minimize the chances of injuries.
+
+Volleyball is essentially a game of transition from one of the above skills to the next, with choreographed team movement between plays on the ball. These team movements are determined by the teams chosen serve receive system, offensive system, coverage system, and defensive system.
+
+The serve-receive system is the formation used by the receiving team to attempt to pass the ball to the designated setter. Systems can consist of 5 receivers, 4 receivers, 3 receivers, and in some cases 2 receivers. The most popular formation at higher levels is a 3 receiver formation consisting of two left sides and a libero receiving every rotation. This allows middles and right sides to become more specialized at hitting and blocking.
+
+Offensive systems are the formations used by the offence to attempt to ground the ball into the opposing court (or otherwise score points). Formations often include designated player positions with skill specialization (see Player specialization, below). Popular formations include the 4-2, 6-2, and 5-1 systems (see Formations, below). There are also several different attacking schemes teams can use to keep the opposing defence off balance.
+
+Coverage systems are the formations used by the offence to protect their court in the case of a blocked attack. Executed by the 5 offensive players not directly attacking the ball, players move to assigned positions around the attacker to dig up any ball that deflects off the block back into their own court. Popular formations include the 2-3 system and the 1-2-2 system. In lieu of a system, some teams just use a random coverage with the players nearest the hitter.
+
+Defensive systems are the formations used by the defence to protect against the ball being grounded into their court by the opposing team. The system will outline which players are responsible for which areas of the court depending on where the opposing team is attacking from. Popular systems include the 6-Up, 6-Back-Deep, and 6-Back-Slide defence. There are also several different blocking schemes teams can employ to disrupt the opposing teams' offence.
+
+When one player is ready to serve, some teams will line up their other five players in a screen to obscure the view of the receiving team. This action is only illegal if the server makes use of the screen, so the call is made at the referee's discretion as to the impact the screen made on the receiving team's ability to pass the ball. The most common style of screening involves a W formation designed to take up as much horizontal space as possible.
+
+There are five positions filled on every volleyball team at the elite level. Setter, Outside Hitter/Left Side Hitter, Middle Hitter, Opposite Hitter/Right Side Hitter and Libero/Defensive Specialist. Each of these positions plays a specific, key role in winning a volleyball match.
+
+At some levels where substitutions are unlimited, teams will make use of a Defensive Specialist in place of or in addition to a Libero. This position does not have unique rules like the libero position, instead, these players are used to substitute out a poor back row defender using regular substitution rules. A defensive specialist is often used if you have a particularly poor back court defender in right side or left side, but your team is already using a libero to take out your middles. Most often, the situation involves a team using a right side player with a big block who must be subbed out in the back row because they aren't able to effectively play backcourt defence. Similarly, teams might use a Serving Specialist to sub out a poor server.
+
+The three standard volleyball formations are known as "4–2", "6–2" and "5–1", which refers to the number of hitters and setters respectively. 4–2 is a basic formation used only in beginners' play, while 5–1 is by far the most common formation in high-level play.
+
+The 4–2 formation has four hitters and two setters. The setters usually set from the middle front or right front position. The team will, therefore, have two front-row attackers at all times. In the international 4–2, the setters set from the right front position. The international 4–2 translates more easily into other forms of offence.
+
+The setters line up opposite each other in the rotation. The typical lineup has two outside hitters. By aligning like positions opposite themselves in the rotation, there will always be one of each position in the front and back rows. After service, the players in the front row move into their assigned positions, so that the setter is always in the middle front. Alternatively, the setter moves into the right front and has both a middle and an outside attacker; the disadvantage here lies in the lack of an offside hitter, allowing one of the other team's blockers to "cheat in" on a middle block.
+
+The clear disadvantage to this offensive formation is that there are only two attackers, leaving a team with fewer offensive weapons.
+
+Another aspect is to see the setter as an attacking force, albeit a weakened force, because when the setter is in the frontcourt they are able to 'tip' or 'dump', so when the ball is close to the net on the second touch, the setter may opt to hit the ball over with one hand. This means that the blocker who would otherwise not have to block the setter is engaged and may allow one of the hitters to have an easier attack.
+
+In the 6–2 formation, a player always comes forward from the back row to set. The three front row players are all in attacking positions. Thus, all six players act as hitters at one time or another, while two can act as setters. So the 6–2 formation is actually a 4–2 system, but the back-row setter penetrates to set.
+
+The 6–2 lineup thus requires two setters, who line up opposite to each other in the rotation. In addition to the setters, a typical lineup will have two middle hitters and two outside hitters. By aligning like positions opposite themselves in the rotation, there will always be one of each position in the front and back rows. After service, the players in the front row move into their assigned positions.
+
+The advantage of the 6–2 is that there are always three front-row hitters available, maximizing the offensive possibilities. However, not only does the 6–2 require a team to possess two people capable of performing the highly specialized role of setter, it also requires both of those players to be effective offensive hitters when not in the setter position. At the international level, only the Cuban National Women's Team employs this kind of formation. It is also used by NCAA teams in Division III men's play and women's play in all divisions, partially due to the variant rules used which allow more substitutions per set than the 6 allowed in the standard rules—12 in matches involving two Division III men's teams[31] and 15 for all women's play.[32]
+
+The 5–1 formation has only one player who assumes setting responsibilities regardless of their position in the rotation. The team will, therefore, have three front-row attackers when the setter is in the back row and only two when the setter is in the front row, for a total of five possible attackers.
+
+The player opposite the setter in a 5–1 rotation is called the opposite hitter. In general, opposite hitters do not pass; they stand behind their teammates when the opponent is serving. The opposite hitter may be used as a third attack option (back-row attack) when the setter is in the front row: this is the normal option used to increase the attack capabilities of modern volleyball teams. Normally the opposite hitter is the most technically skilled hitter of the team. Back-row attacks generally come from the back-right position, known as zone 1, but are increasingly performed from back-centre in high-level play.
+
+The big advantage of this system is that the setter always has 3 hitters to vary sets with. If the setter does this well, the opponent's middle blocker may not have enough time to block with the outside blocker, increasing the chance for the attacking team to make a point.
+
+There is another advantage, the same as that of a 4–2 formation: when the setter is a front-row player, he or she is allowed to jump and "dump" the ball onto the opponent's side. This too can confuse the opponent's blocking players: the setter can jump and dump or can set to one of the hitters. A good setter knows this and thus won't only jump to dump or to set for a quick hit, but when setting outside as well to confuse the opponent.
+
+The 5–1 offence is actually a mix of 6–2 and 4–2: when the setter is in the front row, the offense looks like a 4–2; when the setter is in the back row, the offense looks like a 6–2.
+
+In 2017, a new volleyball union was formed in response to dissatisfaction with the organization and structure of professional beach volleyball tournaments.[33] The union is named the International Beach Volleyball Players Association, and it consists of almost 100 professional players.[33] IBVPA claims its goal is to help athletes and provide them with the means to enjoy playing volleyball by improving the way the sport is run.[33]
+
+Another controversy within the sport is the issue of the inclusion of transgender players.[34] With transgender athletes such as Tifanny Abreu joining professional volleyball teams alongside other non-transgender teammates, many professionals, sports analysts, and fans of volleyball are either expressing concerns about the legitimacy and fairness of having transgender players on a team or expressing support for the transgender people's efforts.[34]
+
+
+
+There are many variations on the basic rules of volleyball. By far the most popular of these is beach volleyball, which is played on sand with two people per team, and rivals the main sport in popularity.
+
+Some games related to volleyball include:

en/6036.html.txt

@@ -0,0 +1,46 @@
+
+
+
+
+Alessandro Giuseppe Antonio Anastasio Volta (Italian: [alesˈsandro ˈvɔlta]; 18 February 1745 – 5 March 1827) was an Italian physicist, chemist, and pioneer of electricity and power[2][3][4] who is credited as the inventor of the electric battery and the discoverer of methane. He invented the Voltaic pile in 1799, and reported the results of his experiments in 1800 in a two-part letter to the President of the Royal Society.[5][6] With this invention Volta proved that electricity could be generated chemically and debunked the prevalent theory that electricity was generated solely by living beings. Volta's invention sparked a great amount of scientific excitement and led others to conduct similar experiments which eventually led to the development of the field of electrochemistry.[6]
+
+Volta also drew admiration from Napoleon Bonaparte for his invention, and was invited to the Institute of France to demonstrate his invention to the members of the Institute. Volta enjoyed a certain amount of closeness with the emperor throughout his life and he was conferred numerous honours by him.[1] Volta held the chair of experimental physics at the University of Pavia for nearly 40 years and was widely idolised by his students.[1]
+
+Despite his professional success, Volta tended to be a person inclined towards domestic life and this was more apparent in his later years. At this time he tended to live secluded from public life and more for the sake of his family until his eventual death in 1827 from a series of illnesses which began in 1823.[1] The SI unit of electric potential is named in his honour as the volt.
+
+Volta was born in Como, a town in present-day northern Italy, on 18 February 1745. In 1794, Volta married an aristocratic lady also from Como, Teresa Peregrini, with whom he raised three sons: Zanino, Flaminio, and Luigi. His father, Filippo Volta, was of noble lineage. His mother, Donna Maddalena, came from the family of the Inzaghis.[7]
+
+In 1774, he became a professor of physics at the Royal School in Como. A year later, he improved and popularised the electrophorus, a device that produced static electricity. His promotion of it was so extensive that he is often credited with its invention, even though a machine operating on the same principle was described in 1762 by the Swedish experimenter Johan Wilcke.[2][8] In 1777, he travelled through Switzerland. There he befriended H. B. de Saussure.
+
+In the years between 1776 and 1778, Volta studied the chemistry of gases. He researched and discovered methane after reading a paper by Benjamin Franklin of the United States on "flammable air". In November 1776, he found methane at Lake Maggiore,[9] and by 1778 he managed to isolate methane.[10] He devised experiments such as the ignition of methane by an electric spark in a closed vessel.
+
+Volta also studied what we now call electrical capacitance, developing separate means to study both electrical potential (V) and charge (Q), and discovering that for a given object, they are proportional.[11] This is called Volta's Law of Capacitance, and for this work the unit of electrical potential has been named the volt.[11]
+
+In 1779 he became a professor of experimental physics at the University of Pavia, a chair that he occupied for almost 40 years.[1]
+
+Luigi Galvani, an Italian physicist, discovered something he named, "animal electricity" when two different metals were connected in series with a frog's leg and to one another. Volta realised that the frog's leg served as both a conductor of electricity (what we would now call an electrolyte) and as a detector of electricity. He also understood that the frog's legs were irrelevant to the electric current, which was caused by the two differing metals.[12] He replaced the frog's leg with brine-soaked paper, and detected the flow of electricity by other means familiar to him from his previous studies.
+In this way he discovered the electrochemical series, and the law that the electromotive force (emf) of a galvanic cell, consisting of a pair of metal electrodes separated by electrolyte, is the difference between their two electrode potentials (thus, two identical electrodes and a common electrolyte give zero net emf). This may be called Volta's Law of the electrochemical series.
+
+In 1800, as the result of a professional disagreement over the galvanic response advocated by Galvani, Volta invented the voltaic pile, an early electric battery, which produced a steady electric current.[13] Volta had determined that the most effective pair of dissimilar metals to produce electricity was zinc and copper. Initially he experimented with individual cells in series, each cell being a wine goblet filled with brine into which the two dissimilar electrodes were dipped. The voltaic pile replaced the goblets with cardboard soaked in brine.
+
+In announcing his discovery of the voltaic pile, Volta paid tribute to the influences of William Nicholson, Tiberius Cavallo, and Abraham Bennet.[14]
+
+The battery made by Volta is credited as one of the first electrochemical cells. It consists of two electrodes: one made of zinc, the other of copper. The electrolyte is either sulfuric acid mixed with water or a form of saltwater brine. The electrolyte exists in the form 2H+ and SO42−. Zinc metal, which is higher in the electrochemical series than both copper and hydrogen, is oxidized to zinc cations (Zn2+) and creates electrons that move to the copper electrode. The positively charged hydrogen ions (protons) capture electrons from the copper electrode, forming bubbles of hydrogen gas, H2. This makes the zinc rod the negative electrode and the copper rod the positive electrode.
+Thus, there are two terminals, and an electric current will flow if they are connected. The chemical reactions in this voltaic cell are as follows:
+
+Copper metal does not react, but rather it functions as an electrode for the electric current. Sulfate anion (SO42-) does not undergo any chemical reaction either, but migrates to the zinc anode to compensate for the charge of the zinc cations formed there.
+However, this cell also has some disadvantages. It is unsafe to handle, since sulfuric acid, even if diluted, can be hazardous. Also, the power of the cell diminishes over time because the hydrogen gas is not released. Instead, it accumulates on the surface of the copper electrode and forms a barrier between the metal and the electrolyte solution.
+
+In 1809 Volta became associated member of the Royal Institute of the Netherlands.[15] In honour of his work, Volta was made a count by Napoleon Bonaparte in 1810.[2]
+
+Volta retired in 1819 to his estate in Camnago, a frazione of Como, Italy, now named "Camnago Volta" in his honour. He died there on 5 March 1827, just after his 82nd birthday.[16] Volta's remains were buried in Camnago Volta.[17]
+
+Volta's legacy is celebrated by the Tempio Voltiano memorial located in the public gardens by the lake. There is also a museum which has been built in his honour, which exhibits some of the equipment that Volta used to conduct experiments.[18] Nearby stands the Villa Olmo, which houses the Voltian Foundation, an organization promoting scientific activities. Volta carried out his experimental studies and produced his first inventions near Como.[19]
+
+His image was depicted on the Italian 10,000 lire note (1990–1997) along with a sketch of his voltaic pile.[20]
+
+In late 2017, Nvidia announced a new workstation-focused microarchitecture called Volta, succeeding Pascal and preceding Turing. The first graphics cards featuring Volta were released in December 2017, with two more cards releasing over the course of 2018.
+
+Volta was raised as a Catholic and for all of his life continued to maintain his belief.[21] Because he was not ordained a clergyman as his family expected, he was sometimes accused of being irreligious and some people have speculated about his possible unbelief, stressing that "he did not join the Church",[22] or that he virtually "ignored the church's call".[23] Nevertheless, he cast out doubts in a declaration of faith in which he said:
+
+I do not understand how anyone can doubt the sincerity and constancy of my attachment to the religion which I profess, the Roman, Catholic and Apostolic religion in which I was born and brought up, and of which I have always made confession, externally and internally. I have, indeed, and only too often, failed in the performance of those good works which are the mark of a Catholic Christian, and I have been guilty of many sins: but through the special mercy of God I have never, as far as I know, wavered in my faith... In this faith I recognise a pure gift of God, a supernatural grace; but I have not neglected those human means which confirm belief, and overthrow the doubts which at times arise. I studied attentively the grounds and basis of religion, the works of apologists and assailants, the reasons for and against, and I can say that the result of such study is to clothe religion with such a degree of probability, even for the merely natural reason, that every spirit unperverted by sin and passion, every naturally noble spirit must love and accept it. May this confession which has been asked from me and which I willingly give, written and subscribed by my own hand, with authority to show it to whomsoever you will, for I am not ashamed of the Gospel, may it produce some good fruit![24][25]

en/6037.html.txt

@@ -0,0 +1,25 @@
+The volt (symbol: V) is the derived unit for electric potential, electric potential difference (voltage), and electromotive force.[1] It is named after the Italian physicist Alessandro Volta (1745–1827).
+
+One volt is defined as the difference in electric potential between two points of a conducting wire when an electric current of one ampere dissipates one watt of power between those points.[2] Equivalently, it is the potential difference between two points that will impart one joule of energy per coulomb of charge that passes through it. It can be expressed in terms of SI base units (m, kg, s, and A) as:
+
+It can also be expressed as amperes times ohms (current times resistance, Ohm's law), webers per second (magnetic flux per time), watts per ampere (power per unit current, definition of electric power), or joules per coulomb (energy per unit charge), which is also equivalent to electronvolts per elementary charge:
+
+The "conventional" volt, V90, defined in 1987 by the 18th General Conference on Weights and Measures[3] and in use from 1990, is implemented using the Josephson effect for exact frequency-to-voltage conversion, combined with the caesium frequency standard.
+
+For the Josephson constant, KJ = 2e/h (where e is the elementary charge and h is the Planck constant), a "conventional" value KJ-90 = 0.4835979 GHz/μV was used for the purpose of defining the volt. As a consequence of the 2019 redefinition of SI base units, the Josephson constant was redefined in 2019 to have an exact value of KJ = 483597.84841698... GHz⋅V−1,[4] which replaced the conventional value KJ-90.
+
+This standard is typically realized using a series-connected array of several thousand or tens of thousands of junctions, excited by microwave signals between 10 and 80 GHz (depending on the array design).[5] Empirically, several experiments have shown that the method is independent of device design, material, measurement setup, etc., and no correction terms are required in a practical implementation.[6]
+
+In the water-flow analogy, sometimes used to explain electric circuits by comparing them with water-filled pipes, voltage (difference in electric potential) is likened to difference in water pressure.  Current is proportional to the diameter of the pipe or the amount of water flowing at that pressure.  A resistor would be a reduced diameter somewhere in the piping and a capacitor/inductor could be likened to a "U" shaped pipe where a higher water level on one side could store energy temporarily.
+
+The relationship between voltage and current is defined (in ohmic devices like resistors) by Ohm's law. Ohm's Law is analogous to the Hagen–Poiseuille equation, as both are linear models relating flux and potential in their respective systems.
+
+The voltage produced by each electrochemical cell in a battery is determined by the chemistry of that cell (see Galvanic cell § Cell voltage). Cells can be combined in series for multiples of that voltage, or additional circuitry added to adjust the voltage to a different level.  Mechanical generators can usually be constructed to any voltage in a range of feasibility.
+
+Nominal voltages of familiar sources:
+
+In 1800, as the result of a professional disagreement over the galvanic response advocated by Luigi Galvani, Alessandro Volta developed the so-called voltaic pile, a forerunner of the battery, which produced a steady electric current. Volta had determined that the most effective pair of dissimilar metals to produce electricity was zinc and silver.  In 1861, Latimer Clark and Sir Charles Bright coined the name "volt" for the unit of resistance.[11]  By 1873, the British Association for the Advancement of Science had defined the volt, ohm, and farad.[12]  In 1881, the International Electrical Congress, now the International Electrotechnical Commission (IEC), approved the volt as the unit for electromotive force.[13]  They made the volt equal to 108 cgs units of voltage, the cgs system at the time being the customary system of units in science.  They chose such a ratio because the cgs unit of voltage is inconveniently small and one volt in this definition is approximately the emf of a Daniell cell, the standard source of voltage in the telegraph systems of the day.[14]  At that time, the volt was defined as the potential difference [i.e., what is nowadays called the "voltage (difference)"] across a conductor when a current of one ampere dissipates one watt of power.
+
+The "international volt" was defined in 1893 as 1/1.434 of the emf of a Clark cell. This definition was abandoned in 1908 in favor of a definition based on the international ohm and international ampere until the entire set of "reproducible units" was abandoned in 1948. [15]
+
+A redefinition of SI base units, including defining the value of the elementary charge, took effect on 20th May 2019.[16]

en/6038.html.txt

@@ -0,0 +1,49 @@
+
+
+The Volvo Group (Swedish: Volvokoncernen; legally Aktiebolaget Volvo, shortened to AB Volvo, stylized as VOLVO) is a Swedish multinational manufacturing company headquartered in Gothenburg. While its core activity is the production, distribution and sale of trucks, buses and construction equipment, Volvo also supplies marine and industrial drive systems and financial services. In 2016, it was the world's second largest manufacturer of heavy-duty trucks.[2]
+
+Automobile manufacturer Volvo Cars, also based in Gothenburg, was part of AB Volvo until 1999, when it was sold to the Ford Motor Company. Since 2010 it has been owned by the Chinese multinational automotive company Geely Holding Group. Both AB Volvo and Volvo Cars share the Volvo logo and cooperate in running the Volvo Museum in Sweden.
+
+The company was first listed on the Stockholm Stock Exchange in 1935, and was on the NASDAQ indices from 1985 to 2007.[3]
+
+Volvo was established in 1915 as a subsidiary of SKF, a ball bearing manufacturer; however both the Volvo Group and Volvo Cars regard the rollout of the company's first car series, the Volvo ÖV 4, on 14 April 1927, as their beginning.[4] The building remains (57°42′50″N 11°55′19″E / 57.71389°N 11.92194°E / 57.71389; 11.92194).
+
+The brand name Volvo was originally registered as a trademark in May 1911 with the intention to be used for a new series of SKF ball bearings. It means "I roll" in Latin, conjugated from "volvere". The idea was short-lived, and SKF decided to simply use its initials as the trademark for all its bearing products.[5]
+
+In 1924, Assar Gabrielsson, an SKF sales manager, and a KTH Royal Institute of Technology educated engineer Gustav Larson,[clarification needed] decided to start construction of a Swedish car. They intended to build cars that could withstand the rigors of the country's rough roads and cold temperatures.[6]
+
+AB Volvo began activities on 10 August 1926. After one year of preparations involving the production of ten prototypes, the firm was ready to commence the car-manufacturing business within the SKF group. The Volvo Group itself considers it started in 1927, when the first car, a Volvo ÖV 4, rolled off the production line at the factory in Hisingen, Gothenburg.[7] Only 280 cars were built that year.[8] The first truck, the "Series 1", debuted in January 1928, as an immediate success and attracted attention outside the country.[5] In 1930, Volvo sold 639 cars,[8] and the export of trucks to Europe started soon after; the cars did not become well known outside Sweden until after World War II.[8] AB Volvo was introduced at the Stockholm Stock Exchange in 1935 and SKF then decided to sell its shares in the company. By 1942, Volvo acquired the Swedish precision engineering company Svenska Flygmotor (later renamed as Volvo Aero).[5]
+
+Pentaverken, which had manufactured engines for Volvo, was acquired in 1935, providing a secure supply of engines and entry into the marine engine market.[9]
+
+The first bus, named B1, was launched in 1934, and aircraft engines were added to the growing range of products at the beginning of the 1940s. In 1963, Volvo opened the Volvo Halifax Assembly plant, the first assembly plant in the company's history outside of Sweden in Halifax, Nova Scotia, Canada.
+
+In 1950, Volvo acquired the Swedish construction and agricultural equipment manufacturer Bolinder-Munktell.[10] Bolinder-Munktell was renamed as Volvo BM in 1973.[11] In 1979, Volvo BM's agricultural equipment business was sold to Valmet.[12] Later, through restructuring and acquisitions, the remaining construction equipment business became Volvo Construction Equipment.[10]
+
+In 1977, Volvo tried to combine operations with rival Swedish automotive group Saab-Scania, but the latter company rejected it.[5] In the 1970s, French manufacturer Renault and Volvo started to collaborate.[13] In 1978, Volvo Car Corporation was spun off as a separate company within the Volvo group[14] and Renault acquired a minority stake,[5] before selling it back in the 1980s after a restructuring.[13] In the 1990s, Renault and Volvo deepened their collaboration and both companies partnered in purchasing, research and development and quality control while increasing their cross-ownership. Renault would assist Volvo with entry-level and medium segment vehicles and in return Volvo would share technology with Renault in upper segments. In 1993, a 1994 Volvo-Renault merger deal was announced. The deal was barely accepted in France, but it was opposed in Sweden, and the Volvo shareholders and company board voted against it.[5][13] The alliance was officially dissolved in February 1994 and Volvo sold off its minority Renault stake in 1997.[5]
+
+In 1991, the Volvo Group participated in a joint venture with Japanese automaker Mitsubishi Motors  at the former DAF plant in Born, Netherlands. The operation, branded NedCar, began producing the first generation Mitsubishi Carisma alongside the Volvo S40/V40 in 1996.[15][16] During the 1990s, Volvo also partnered with the American manufacturer General Motors. In 1999, the European Union blocked a merger with Scania AB.[5]
+
+In January 1999, Volvo Group sold Volvo Car Corporation to Ford Motor Company for $6.45 billion. The division was placed within Ford's Premier Automotive Group alongside Jaguar, Land Rover and Aston Martin. Volvo engineering resources and components would be used in various Ford, Land Rover and Aston Martin products, with the second generation Land Rover Freelander designed on the same platform as the second generation Volvo S80. The Volvo T5 petrol engine was used in the Ford Focus ST and RS performance models, and Volvo's satellite navigation system was used on certain Aston Martin Vanquish, DB9 and V8 Vantage models.[17][18][19] In November 1999, Volvo Group purchased a 5% stake in Mitsubishi Motors, as part of a partnership deal for the truck and bus business.[20] In 2001, after DaimlerChrysler bought a large Mitsubishi Motors stake,[21] Volvo sold its shares to the former.[22]
+
+Renault Véhicules Industriels (which included Mack Trucks, but not Renault's stake in Irisbus) was sold to Volvo during January 2001, and Volvo renamed it Renault Trucks in 2002. Renault became AB Volvo's biggest shareholder with a 19.9% stake (in shares and voting rights) as part of the deal.[23] Renault increased its shareholding to 21.7% by 2010.[24]
+
+AB Volvo acquired 13% of the shares in the Japanese truck manufacturer Nissan Diesel (later renamed UD Trucks) from Nissan (part of the Renault-Nissan Alliance) during 2006, becoming a major shareholder. Volvo Group took complete ownership of Nissan Diesel in 2007 to extend its presence in the Asian Pacific market.[6][25]
+
+Renault sold 14.9% of their stake in AB Volvo in October 2010 (comprising 14.9% of the share capital and 3.8% of the voting rights) for €3.02 billion. This share sale left Renault with around 17.5% of Volvo's voting rights.[24] Renault sold their remaining shares in December 2012 (comprising 6.5% of the share capital and 17.2% of the voting rights at the time of transaction) for €1.6 billion, leaving Swedish industrial investment group Aktiebolaget Industrivärden as the largest shareholder, with 6.2% of the share capital and 18.7% of the voting rights.[26][27] That same year, Volvo sold Volvo Aero to the British company GKN.[28] In 2017 Volvo Cars owner Geely became the largest Volvo shareholder by number of shares after acquiring an 8.2% stake, displacing Industrivärden. Industrivärden kept more voting rights than Geely (Geely getting a 15.8%).[29]
+
+In December 2013, Volvo sold its Volvo Construction Equipment Rents division to Platinum Equity.[30] In 2014, Volvo's Volvo Construction Equipment acquired the haul truck manufacturing division of Terex Corporation, which included five truck models and a manufacturing facility in Motherwell, Scotland.[31][32][33] In November 2016, Volvo announced its intention of divesting its Government Sales division, made up mainly of Renault Trucks' Renault Trucks Defense but also of Panhard, ACMAT, Mack Defense in the United States, and Volvo Defense.[34] The project for selling the division was later abandoned and, in May 2018, Volvo reorganized Renault Trucks Defense and renamed it Arquus.[35]
+
+In December 2018, Volvo announced it intended to sell a 75.1% controlling stake of its car telematics subsidiary WirelessCar to Volkswagen with the aim of focusing on telematics for commercial vehicles.[36] The sale was completed in March 2019.[37]
+
+In December 2019, Volvo and Isuzu announced their intention of forming a strategic alliance on commercial vehicles. As part of the agreement, Volvo would sell UD Trucks to Isuzu.[38] In April 2020, Volvo and Daimler announced that the former planned to acquire half of Daimler's fuel cell business, forming a joint venture between the two companies.[39]
+
+Volvo Group's operations include:
+
+Volvo Trademark Holding AB is equally owned by AB Volvo and Volvo Car Corporation.[41]
+
+The main activity of the company is to own, maintain, protect and preserve the Volvo trademarks (including Volvo, the Volvo device marks (grille slash & iron mark) Volvo Aero and Volvo Penta) on behalf of its owners and to license these rights to its owners. The day-to-day work is focused upon maintaining the global portfolio of trademark registrations and to extend sufficiently the scope of the registered protection for the Volvo trademarks.
+
+The main business is also to act against unauthorised registration and use (including counterfeiting) of trademarks identical or similar to the Volvo trademarks on a global basis.[42]
+
+Volvo has a strategic collaboration within research and recruitment with a number of selected colleges and universities such as Penn State University, INSA Lyon, EMLYON  Business School, NC State University, Sophia University, Chalmers University of Technology, The Gothenburg School of Business, Economics and Law at the University of Gothenburg, Mälardalen University College, and the University of Skövde.[43]