Datasets:

scillm

/

scientific_papers-archive

like 4

Follow

scillm_su23 10

Suppose that you have an abstract for a scientific paper: we present the first completely analytical computation of the full differential @xmath0-@xmath0 pair production rate from compact radiation fields , exact to 2nd order qed , and use this result to investigate the validity of previously known approximations . . And you have already written the first three sentences of the full article: the discovery of high - energy @xmath0-radiation from extragalactic compact objects has motivated many authors to consider the effects of @xmath0-ray absorption by @xmath0-@xmath0 pair production , eventually inducing pair cascades . the relevance of @xmath0-@xmath0 pair production to astrophysical systems has first been pointed out by nikishov ( 1962 ) . the first investigation of the @xmath0-@xmath0 absorption probability of high - energy photons by different soft photon fields , along with some useful approximations , can be found in gould & schrder ( 1967 ) .. Please generate the next two sentences of the article

the energy spectrum of injected electrons and positrons due to this process has been studied by several authors ( e. g. , bonometto & rees 1971 , aharonian et al . 1983 , zdziarski & lightman 1985 , coppi & blandford 1990 ) . in most astrophysically relevant cases , simple approximations can be used for this purpose , without much loss of accuracy .

Suppose that you have an abstract for a scientific paper: we derive a general expression for the electron nonequilibrium ( ne ) distribution function in the context of steady state quantum transport through a two - terminal nanodevice with interaction . the central idea for the use of ne distributions for open quantum systems is that both the ne and many - body ( mb ) effects are taken into account in the statistics of the finite size system connected to reservoirs . we develop an alternative scheme to calculate the ne steady state properties of such systems . the method , using ne distribution and spectral functions , presents several advantages , and is equivalent to conventional steady - state ne green s functions ( negf ) calculations when the same level of approximation for the mb interaction is used . the advantages of our method resides in the fact that the ne distribution and spectral functions have better analytic behaviour for numerical calculations . furthermore our approach offer the possibility of introducing further approximations , not only at the level of the mb interaction as in negf , but also at the level of the functional form used for the ne distributions . for the single level model with electron - phonon coupling we have considered , such approximations provide a good representation of the exact results , for either the ne distributions themselves or the transport properties . we also derive the formal extensions of our method for systems consisting of several electronic levels and several vibration modes . . And you have already written the first three sentences of the full article: the understanding of irreversible phenomena including nonequilibrium ( ne ) steady state is a long - standing problem of quantum statistical mechanics . with the recent experimental developments , it is now possible to measure the transport properties through nanoscale systems . these can be either the electronic charge transport or heat transport . both properties , i.e. thermoelectric transport , have recently been measured simultaneously @xcite .. Please generate the next two sentences of the article

such properties exhibit many important new features in comparison with conduction through macroscopic systems . in particular , the interactions , such as coulomb interaction between electrons and scattering from atomic vibrations , become critically important in nanoscale objects , especially in single organic molecules @xcite modelling such transport properties is still a challenge since one needs to be able to describe the system at the atomic level in a realistic manner , and one needs to use a formalism for the quantum transport that takes full account of the ne conditions ( full nonlinear response ) and the many - body ( mb ) interaction .

Suppose that you have an abstract for a scientific paper: the spectral function of @xmath0he is extracted from a plane - wave approximation to the @xmath1 reaction using a fully relativistic formalism . we take advantage of both an algebraic `` trick '' and a general relativistic formalism for quasifree processes developed earlier to arrive at transparent , analytical expressions for all quasifree @xmath1 observables . an observable is identified for the clean and model - independent extraction of the spectral function . our simple relativistic plane - wave calculations provide baseline predictions for the recently measured , but not yet fully analyzed , momentum distribution of @xmath0he by the @xmath2-collaboration from mainz . yet in spite of its simplicity , our approach predicts momentum distributions for @xmath0he that rival some of the best nonrelativistic calculations to date . finally , we highlight some of the challenges and opportunities that remain , both theoretically and experimentally , in the extraction of quasifree observables . . And you have already written the first three sentences of the full article: electron scattering from nuclei is a common and powerful tool for studying the structure of nuclei . the method relies on our superior understanding of quantum electrodynamics ( qed ) and the relative ease by which qed may be applied to a variety of processes , at least in the one - photon - exchange approximation . in inclusive @xmath3 electron scattering all nuclear - structure information is contained in two dynamical quantities : the longitudinal and transverse response functions .. Please generate the next two sentences of the article

the longitudinal response is sensitive to the distribution of charge in the nucleus while the transverse response samples the distribution of currents and magnetization . measurement of these quantities in the quasielastic region is expected to be particularly clean as the reactive content of the reaction is dominated by quasifree proton knockout .

Suppose that you have an abstract for a scientific paper: near - infrared and optical imaging of hd32297 indicate that it has an edge - on debris disk , similar to @xmath0 pic . i present high resolution optical spectra of the doublet toward hd32297 and stars in close angular proximity . a circumstellar absorption component is clearly observed toward hd32297 at the stellar radial velocity , which is not observed toward any of its neighbors , including the nearest only 0@xmath19 away . an interstellar component is detected in all stars @xmath290pc , including hd32297 , likely due to the interstellar material at the boundary of the local bubble . radial velocity measurements of the nearest neighbors , bd+07777s and bd+07778 , indicate that they are unlikely to be physically associated with hd32297 . the measured circumstellar column density around hd32997 , @xmath3 , is the strongest absorption measured toward any nearby main sequence debris disk , even the prototypical edge - on debris disk , @xmath0 pic . assuming that the morphology and abundances of the gas component around hd32297 are similar to @xmath0 pic , i estimate an upper limit to the gas mass in the circumstellar disk surrounding hd32297 of @xmath40.3 @xmath5 . . And you have already written the first three sentences of the full article: debris disk systems provide a look at an intermediate stage of stellar system evolution . they represent the transition between the early formation of stars and planets in a primordial protoplanetary disk as seen toward pre - main sequence stars , and the mature stage of an evolved system , like our solar system , which is clear of all primordial material and retains only a hint of secondary products ( e.g. , zodiacal dust ) , the final remnants of the stellar and planetary formation process . although a debris disk has lost most of its primordial material , the observed infrared luminosity of circumstellar dust , caused by collisions of planetismals and other small bodies , is typically several orders of magnitude larger than estimated for the kuiper and asteroid belts in our solar system @xcite .. Please generate the next two sentences of the article

ever since the detection of dusty circumstellar material around main sequence stars via infrared excesses @xcite , researchers have been looking for circumstellar gas phase absorption @xcite . of the initial major infrared excess main sequence stars , only @xmath0 pic showed gas phase absorption in optical absorption lines ( e.g. , and ) , due to its disk morphology and edge - on orientation @xcite .

Suppose that you have an abstract for a scientific paper: the spin seebeck effect is studied across a charge insulating magnetic junction , in which thermal - spin conjugate transport is assisted by the exchange interactions between the localized spin in the center and electrons in metallic leads . we show that , in contrast with bulk spin seebeck effect , the figure of merit of such nanoscale thermal - spin conversion can be infinite , leading to the ideal carnot efficiency in the linear response regime . we also find that in the nonlinear spin seebeck transport regime , the device possesses the asymmetric and negative differential spin seebeck effects . in the last , the situations with leaking electron tunneling are also discussed . this nanoscale thermal spin rectifier , by tuning the junction parameters , can act as a spin seebeck diode , spin seebeck transistor and spin seebeck switch , which could have substantial implications for flexible thermal and information control in molecular spin caloritronics . . And you have already written the first three sentences of the full article: energy waste is a severe bottleneck in the supply of sustainable energy to any modern economy . besides developing new energy sources , the global energy crisis can be alleviated by re - utilizing the wasted energy . in view of the fact that about 90% of the world s energy utilization occurs in the form of heat , effective heat control and conversion become critical @xcite . to meet the desire , phononics @xcite has been proposed to control heat energy and information in a similar style as controlling electric current and signal in electronics .. Please generate the next two sentences of the article

various functional thermal devices such as thermal rectifiers and transistors are then designed , essentially based on two intriguing properties : the heat diode effect and negative differential thermal conductance [ e.g. , see refs . ] . meanwhile , the investigation on interplay of spin and heat transport has attracted great interest .

Suppose that you have an abstract for a scientific paper: we show that the newly measured branching ratios of vector charmonia ( @xmath0 , @xmath1 and @xmath2 into @xmath3 , where @xmath4 stands for light pseudoscalar mesons @xmath5 , @xmath6 , and @xmath7 , can be well understood in the framework of vector meson dominance ( vmd ) in association with the @xmath8-@xmath9 mixings due to the axial gluonic anomaly . these two mechanisms behave differently in @xmath0 and @xmath10 . a coherent understanding of the branching ratio patterns observed in @xmath11 can be achieved by self - consistently including those transition mechanisms at hadronic level . the branching ratios for @xmath12 are predicted to be rather small . . And you have already written the first three sentences of the full article: the recent measurements of the vector charmonium radiative decays to light pseudoscalars , i.e. @xmath0 , @xmath1 and @xmath13 , @xmath14 and @xmath15 , have brought surprises and interests to us . earlier , the cleo collaboration @xcite renewed the branching ratios for @xmath16 , @xmath17 , @xmath18 , and @xmath19 , which are consistent with the averages from 2008 particle data group @xcite . the branching ratio upper limits for @xmath20 and @xmath17 were set , which were more than one order of magnitude smaller than that for @xmath19 .. Please generate the next two sentences of the article

meanwhile , the upper limits for @xmath21 , where @xmath4 stands for pseudoscalar @xmath5 , @xmath6 and @xmath7 , were set to be about @xmath22 . the @xmath1 radiative decays are also investigated by the besiii collaboration with the newly collected 106 million @xmath1 events , and the results turn out to be tantalizing .

Suppose that you have an abstract for a scientific paper: phase transitions can occur in one - dimensional classical statistical mechanics at non - zero temperature when the number of components @xmath0 of the spin is infinite . we show how to solve such magnets in one dimension for any @xmath0 , and how the phase transition develops at @xmath1 . we discuss @xmath2 and @xmath3 magnets , where the transition is second - order . in the new high - temperature phase , the correlation length is zero . we also show that for the @xmath2 magnet on exactly three sites with periodic boundary conditions , the transition becomes first order . . And you have already written the first three sentences of the full article: it has long been known that phase transitions are uncommon in one - dimensional classical statistical mechanics . an old argument by peierls shows that in models at non - zero temperature with local interactions and a finite number of degrees of freedom , order is not possible : the entropy gain from disordering the system will always dominate the energy loss . there are ( at least ) three ways of avoiding this argument .. Please generate the next two sentences of the article

the first two are well understood . a system at zero temperature can of course order : the system just sits in its ground state . a system with long - range interactions can have an energy large enough to dominate the entropy . in this paper

Suppose that you have an abstract for a scientific paper: we present _ spitzer _ images of the relatively sparse , low luminosity young cluster l988e , as well as complementary near - infrared ( nir ) and submillimeter images of the region . the cluster is asymmetric , with the western region of the cluster embedded within the molecular cloud , and the slightly less dense eastern region to the east of , and on the edge of , the molecular cloud . with these data , as well as with extant h@xmath0 data of stars primarily found in the eastern region of the cluster , and a molecular @xmath1co gas emission map of the entire region , we investigate the distribution of forming young stars with respect to the cloud material , concentrating particularly on the differences and similarities between the exposed and embedded regions of the cluster . we also compare star formation in this region to that in denser , more luminous and more massive clusters already investigated in our comprehensive multi - wavelength study of young clusters within 1 kpc of the sun . . And you have already written the first three sentences of the full article: lynds 988e ( l988e = iras 21023 + 5002 ) was identified as one of six iras point sources ( l988a - f ) observed toward the l988 dark cloud , which is located on the edge of the cygnus ob7 molecular cloud association @xcite and which contains several bright , pre - main sequence objects . bipolar molecular outflows were discovered @xcite to be associated with the vicinity of l988e , as well as the vicinity of l988a and l988f , and there is also high velocity co emission ( blue - shifted lobe only ) to the west of l988c . there are two lkh@xmath0 objects and related nebulosity seen both at visible and infrared wavelengths , lkh@xmath0 324-se and lkh@xmath0 324 , the brightest cluster members of a region of @xmath250 h@xmath0 emission - line stars @xcite on the edge of the heavy extinction associated with l988e s parent molecular cloud .. Please generate the next two sentences of the article

most of these emission - line stars lie to the east of the molecular cloud or on its eastern edge . lkh@xmath0 324 is a herbig ae / be ( haebe ) star , close ( in projection ) to the iras coordinate , and lkh@xmath0 324-se ( misidentified as lkh@xmath0 324 in the the herbig and bell catalog @xcite ) is probably also an haebe star @xcite .

Suppose that you have an abstract for a scientific paper: we analyse an epidemiological model of competing strains of pathogens and hence differences in transmission for first versus secondary infection due to interaction of the strains with previously aquired immunities , as has been described for dengue fever ( in dengue known as antibody dependent enhancement , ade ) . such models show a rich variety of dynamics through bifurcations up to deterministic chaos . including temporary cross - immunity even enlarges the parameter range of such chaotic attractors , and also gives rise to various coexisting attractors , which are difficult to identify by standard numerical bifurcation programs using continuation methods . a combination of techniques , including classical bifurcation plots and lyapunov exponent spectra has to be applied in comparison to get further insight into such dynamical structures . here we present for the first time multi - parameter studies in a range of biologically plausible values for dengue . the multi - strain interaction with the immune system is expected to also have implications for the epidemiology of other diseases . numerical bifurcation analysis , lyapunov exponents , @xmath0 symmetry , coexisting attractors , antibody dependent enhancement ( ade ) regino criado , j. vigo aguiar maira@igc.gulbenkian.pt1 nico@ptmat.fc.ul.pt1 kooi@falw.vu.nl2 . And you have already written the first three sentences of the full article: epidemic models are classically phrased in ordinary differential equation ( ode ) systems for the host population divided in classes of susceptible individuals and infected ones ( sis system ) , or in addition , a class of recovered individuals due to immunity after an infection to the respective pathogen ( sir epidemics ) . the infection term includes a product of two variables , hence a non - linearity which in extended systems can cause complicated dynamics . though these simple sis and sir models only show fixed points as equilibrium solutions , they already show non - trivial equilibria arising from bifurcations , and in stochastic versions of the system critical fluctuations at the threshold . further refinements of the sir model in terms of external forcing or distinction of infections with different strains of a pathogen , hence classes of infected with one or another strain recovered from one or another strain , infected with more than one strain etc .. Please generate the next two sentences of the article

, can induce more complicated dynamical attractors including equilibria , limit cycles , tori and chaotic attractors . classical examples of chaos in epidemiological models are childhood diseases with extremely high infection rates , so that a moderate seasonal forcing can generate feigenbaum sequences of period doubling bifurcations into chaos .

Suppose that you have an abstract for a scientific paper: in order to clarify thermodynamic stability of mg - based long - period stacking ordered ( lpso ) structure , we systematically study energetic preference for alloys on multiple stacking with different composition for random mixing of constituent elements , mg , y , and zn based on special quasirandom structure ( sqs ) . through calculation of formation free energy of sqs , mg - y - zn alloy exhibits phase separation into mg- and y - zn rich phase , which is consistent with previous theoretical studies . bulk modulus of sqss for multiple compositions , stacking sequences , and atomic configurations ranges around 35 gpa , @xmath0 , they do not show significant dependence of mg concentration , which therefore means that the effects of phonon do not play significant role on lpso phase stability . introducing stacking fault to hcp stacking gains `` negative '' energy , which indicates profound relationship between introducing stacking faults and the formation of long - period stacking ordering . . And you have already written the first three sentences of the full article: for its remarkable high tensile strength and ductility @xcite , mg - based long - period stacking ordered ( lpso ) structures are considered as light - weight structural alloy for next generation . in order to clarify relationship between thier formation process and resultant properties in terms of application for structural materials , considerable number of experimental as well as theoretical studies have been carried out . previous theoretical studies mainly address formation process and thermodynamic stability of mg - based lpso alloy , including ( i ) the tendency of phase separation confirmed by cluster variation method @xcite , ( ii ) in - plane ordering of clusters consisted of y , zn substitutional atoms @xcite , and ( iii ) systematic understanding of energetic stability with respect to variety of substitutional atoms into mg - based alloys @xcite . although these previous theoretical works partly clarify themodynamic stability of lpso phases , they did not sufficiently discuss about ( i ) relative stability in terms of disordered phases or ( ii ) effect of lattice vibration on stability of lpso .. Please generate the next two sentences of the article

the former one is considered essentially important , since well - established ordering energy , determining the thermodynamic stability of ordered phase with respect to temperature , is typically reffered to the difference in mixing energy between ordered ( here , lpso ) and disordered phases . for the latter one , vibrational effects , their significant role on phase stability has been amply demonstrated for several binary alloys , such as ref .

Suppose that you have an abstract for a scientific paper: in the limit of heavy quark masses going to infinity , a symmetry is known to emerge in qcd relating properties of hadrons with two heavy quarks to analogous states with one heavy anti - quark . a key question is whether the charm mass is heavy enough so that this symmetry is manifest in at least an approximate manner . the issue is crucial in attempting to understand the recent reports by the selex collaboration of doubly charmed baryons . we argue on very general grounds that the charm quark mass is substantially too light for the symmetry to emerge automatically via colour coulombic interactions . however , the symmetry could emerge approximately depending on the dynamical details of the non - perturbative physics . to treat the problem systematically , a new expansion that simultaneously incorporates nrqcd and hqet is needed . . And you have already written the first three sentences of the full article: it has been known for some time that in the limit of arbitrarily large heavy quark masses that qcd has a symmetry which relates hadrons with two heavy quarks ( anti - quarks ) to analogous states with one heavy anti - quark ( quark ) @xcite . we will refer to this symmetry as the doubly heavy diquark antiquark ( dhda ) symmetry .. Please generate the next two sentences of the article

presumably when the masses are finite , but very large , a remnant of this dhda symmetry will survive in the form of an approximate symmetry . a key issue is how large must the masses be before such an approximate dhda symmetry is manifest in a useful way .

Suppose that you have an abstract for a scientific paper: a rarity among supernova , sn 1993j in m81 can be studied with high spatial resolution . its radio power and distance permit vlbi observations to monitor the expansion of its angular structure . this radio structure was previously revealed to be shell - like and to be undergoing a self - similar expansion at a constant rate . from vlbi observations at the wavelengths of 3.6 and 6 cm in the period 6 to 42 months after explosion , we have discovered that the expansion is decelerating . our measurement of this deceleration yields estimates of the density profiles of the supernova ejecta and circumstellar material in standard supernova explosion models . . And you have already written the first three sentences of the full article: supernova sn 1993j in m81 discovered by francisco garca of lugo , spain ( @xcite ) is a type iib supernova ( sn ) whose red giant progenitor probably had a mass of 12 - 16 while on the main sequence ; at the time of the explosion , 3 - 5 likely remained in the he core and @xmath01 in the he / h envelope ( @xcite , @xcite , @xcite , @xcite ) . the first maximum in the supernova optical light curve has been attributed to shock heating of the thin envelope and the second to radioactive decay of @xmath1co ( @xcite , @xcite , @xcite ) . modelling of the x - ray emission ( @xcite ) also implies a relatively low mass envelope due to interaction with a binary companion ( @xcite , @xcite ) .. Please generate the next two sentences of the article

+ the standard circumstellar interaction model hereafter standard model or sm for radio supernovae ( @xcite and references therein ) suggests that the radio emission arises from a shocked region between the supernova ejecta and the circumstellar material ( csm ) that results from the wind of the sn s progenitor star . more specifically , the sm considers sn ejecta with steep density profiles ( @xmath2 ) shocked by a reverse shock that moves inwards from the contact surface and a csm with density profile @xmath3 shocked by a forward shock that moves outwards from the contact surface ( @xmath4=2 corresponds to a steady wind ) . for @xmath5@xmath65 ,

Suppose that you have an abstract for a scientific paper: bell - state analysis ( bsa ) is essential in quantum communication , but it is impossible to distinguish unambiguously the four bell states in the polarization degree of freedom ( dof ) of two - photon systems with only linear optical elements , except for the case in which the bsa is assisted with hyperentangled states , the simultaneous entanglement in more than one dof . here , we propose a scheme to distinguish completely the 16 hyperentangled bell states in both the polarization and the spatial - mode dofs of two - photon systems , by using the giant nonlinear optics in quantum dot - cavity systems . this scheme can be applied to increase the channel capacity of long - distance quantum communication based on hyperentanglement , such as entanglement swapping , teleportation , and superdense coding . we use hyperentanglement swapping as an example to show the application of this hbsa . . And you have already written the first three sentences of the full article: entanglement is a key quantum resource for quantum information processing and it plays a critical role in many important applications in quantum communication , such as quantum key distribution @xcite , quantum dense coding @xcite , quantum teleportation @xcite , and entanglement swapping @xcite . some important goals in quantum communication require the complete and deterministic analysis of the bell states . in 1999 , vaidman s @xcite and l@xmath0tkenhau s @xcite groups put forward a bell - state analysis ( bsa ) for teleportation with only linear optical elements . unfortunately , with linear - optical elements , one can obtain the optimal success probability of 50% both in theory @xcite and in experiment @xcite ( of course , by guessing at random when an ambiguous result is obtained , one can technically achieve a 75% success rate in identifying the four bell states ) .. Please generate the next two sentences of the article

the bsa on photon pairs entangled in one degree of freedom ( dof ) attracted much attention @xcite . the entanglement of photon pairs in several dofs @xcite , called it hyperentanglement , is useful in quantum information processing , especially in quantum communication for completing bsa on polarizations of photon pairs @xcite , performing entanglement purification @xcite , distributing entangled polarization states faithfully @xcite , or improving the channel capacity .

Suppose that you have an abstract for a scientific paper: the dynamics of particles moving in a medium defined by its relativistically invariant stochastic properties is investigated . for this aim , the force exerted on the particles by the medium is defined by a stationary random variable as a function of the proper time of the particles . the equations of motion for a single one - dimensional particle are obtained and numerically solved . a conservation law for the drift momentum of the particle during its random motion is shown . moreover , the conservation of the mean value of the total linear momentum for two particles repelling each other according with the coulomb interaction is also following . therefore , the results indicate the realization of a kind of stochastic noether theorem in the system under study . possible applications to the stochastic representation of quantum mechanics are advanced . . And you have already written the first three sentences of the full article: stochastic processes made their appearance in research in physics long time ago and their theory has played an important role in the description of systems which do not behave in a deterministic manner @xcite . in particular , the study of the dynamics of particles lying inside material media has been the object of high interest . a classical example is the study of the brownian motion @xcite . a large deal of those investigations had a non - relativistic character and the random interactions with the background medium were considered as being dependent of the state of motion of the particle , that is , lacking invariance under the changes of the reference system @xcite .. Please generate the next two sentences of the article

another large class of studies in this field had been directed to show the equivalence with random processes of the solutions of quantum relativistic or non - relativistic equations , like the klein - gordon , dirac and schrodinger ones . @xcite . two basic additional subjects in connection with stochastic processes in quantum theory are : the attempts to derive the collapse of the wave function during measurements from the existence of random perturbations in quantum mechanics ( qm ) @xcite , and the study of the decoherence processes and their role in spontaneous transitions from pure to mixed states @xcite .

Suppose that you have an abstract for a scientific paper: the good energy resolution ( 34 kev fwhm ) of the transient gamma ray spectrometer ( tgrs ) on board the _ wind _ spacecraft makes it sensitive to doppler - shifted outbursts of 511 kev electron - positron annihilation radiation , the reason being that the doppler shift causes the cosmic line to be slightly offset from a strong instrumental background 511 kev line at rest , which is ubiquitous in space environments . such a cosmic line ( blueshifted ) is predicted to arise in classical novae due to the annihilation of positrons from @xmath0-decay on a timescale of a few hours in an expanding envelope . a further advantage of tgrs its broad field of view , containing the entire southern ecliptic hemisphere has enabled us to make a virtually complete and unbiased 3year search for classical novae at distances up to @xmath1 kpc . we present negative results of this search , and estimate its implications for the highly - uncertain galactic classical nova rate and for future space missions . . And you have already written the first three sentences of the full article: classical novae are rather frequently observed in our galaxy ( liller & mayer 1987 , shafter 1997 ) , and have also been studied in external galaxies ; typically @xmath2 34 per year are detected in our galaxy ( duerbeck 1995 , warner 1995 ) . most of the discoveries and observations of galactic novae have been made by amateur astronomers with little access to spectroscopic and photometric equipment . sky coverage has been episodic and extremely hard to calculate .. Please generate the next two sentences of the article

classification attempts have also been hindered . as a result , many of the most basic properties involving their global rate and distribution are surprisingly uncertain . for example , a number of arguments suggest that the galactic rate of novae must be much higher than @xmath3 : \(a ) the typical limiting apparent magnitude obtainable with amateur apparatus and methods has been increasing steadily in recent years , but for the period covered by this paper may be taken to be @xmath4 , within a very wide range , and with extremely uneven coverage . application of the expanding - photosphere method to a subset of relatively nearby and bright novae has yielded the empirical relation @xmath5 ( warner 1995 ) for the absolute magnitude , where @xmath6 ( the _ speed class _ ) is the time taken for @xmath7 to increase by 2 from discovery .

Suppose that you have an abstract for a scientific paper: the parametrisation of the photon structure function in the low @xmath0 region is formulated . it includes the vmd contribution and the qcd improved parton model component suitably extrapolated to the low @xmath0 region . the parametrisation describes reasonably well existing experimental data on @xmath1 for real photons and the low @xmath0 data on @xmath2 . predictions for @xmath1 and for @xmath2 for energies which may be accesssible in future linear colliders are also given . * @xmath3 at low @xmath0 + and @xmath1 at high energies * + , j. kwieciski @xmath4 and a. m. stato @xmath4 + @xmath5 _ department of physics , uppsala university , p.o.box 530 , 751 21 uppsala , sweden _ + _ and institute of experimental physics , warsaw university , hoa 69 , 00 - 681 warsaw , poland _ + @xmath4 _ department of theoretical physics , h. niewodniczaski institute of nuclear physics , + radzikowskiego 152 , 31 - 342 cracow , poland _ + the structure function of the photon is described at large scales @xmath0 by the qcd improved parton model @xcite . it is expected however that in the low @xmath0 region the vector meson dominance ( vmd ) contribution @xcite may also become important . here , as usual , @xmath6 where @xmath7 denotes the four momentum of the virtual photon probing the real photon with four momentum @xmath8 . the cm energy squared @xmath9 of the @xmath10 system is @xmath11 . + in this talk we wish to present the representation of the photon structure function which includes both the vmd contribution together with the qcd improved parton model term suitably extrapolated to the low @xmath0 region . this representation of the photon structure function is based on the extension of similar representation of the nucleon structure function to the case of the photon `` target '' @xcite . possible parametrization of the photon structure function which extends to the low @xmath0 region has also been discussed in ref . @xcite . there do also exist several microscopic models.... And you have already written the first three sentences of the full article: we congratulate marek jeabek for organizing an excellent conference . we thank maria krawczyk for several useful discussions . this research was partially supported by the polish state committee for scientific research grants 2 p03b 184 10 , 2 p03b 89 13 and by the eu fourth framework programme `` training and mobility of researchers '' , network quantum chromodynamics and the deep structure of elementary particles , contract fmrx - ct98 - 0194 . 9999 h. abramowicz , m. krawczyk , k. charchua , a. levy , u. maor , int . j. mod. Please generate the next two sentences of the article

a8 * ( 1993 ) 1005 and references therein . report of the working group on @xmath12 physics , p. aurenche , g.a .

Suppose that you have an abstract for a scientific paper: community detection is the process of assigning nodes and links in significant communities ( e.g. clusters , function modules ) and its development has led to a better understanding of complex networks . when applied to sizable networks , we argue that most detection algorithms correctly identify prominent communities , but fail to do so across multiple scales . as a result , a significant fraction of the network is left uncharted . we show that this problem stems from larger or denser communities overshadowing smaller or sparser ones , and that this effect accounts for most of the undetected communities and unassigned links . we propose a generic cascading approach to community detection that circumvents the problem . using real network datasets with two widely used community detection algorithms , we show how cascading detection allows for the detection of the missing communities and results in a significant drop of the fraction of unassigned links . = 1 . And you have already written the first three sentences of the full article: over the course of the last decade , network science has attracted an ever growing interest since it provides important insights on a large class of interacting complex systems . one of the features that has drawn much attention is the structure of interactions highlighted by the network representation . indeed , it has become increasingly clear that global structural patterns emerge in most real networks @xcite .. Please generate the next two sentences of the article

one such pattern , where links and nodes are aggregated into larger groups , is called the community structure of a network . while the exact definition of communities is still not agreed upon @xcite , the general consensus is that these groups should be denser than the rest of the network .

Suppose that you have an abstract for a scientific paper: we have studied the distribution of @xmath0 galaxies from the roe / nrl cosmos / ukst catalogue around two samples of @xmath1 qsos with similar redshift distributions . the first sample is formed by 144 radio - loud qsos from the parkes catalogue , and the other contains 167 optically selected qsos extracted from the large bright quasar survey . it is found that there is a @xmath2 significance level excess of cosmos / ukst galaxies around the pks qsos , whereas there is a marginal defect of galaxies around the lbqs qsos . when the distribution of galaxies around both samples is compared , we found that there is an overdensity of galaxies around the pks sample with respect to the lbqs sample anticorrelated with the distance from the qsos at a @xmath3 significance level . although this result apparently agrees with the predictions of the multiple magnification bias , it is difficult to explain by gravitational lensing effects alone ; dust in the foreground galaxies and selection effects in the detection of lbqs qsos should be taken into account . it has been established that the lines of sight to pks flat - spectrum qsos go through significatively higher foreground galaxy densities than the directions to lbqs quasars , what may be partially related with the reported reddening of pks qsos . . And you have already written the first three sentences of the full article: in the last few years , several studies have established the existence of a statistical excess of line - of - sight companion galaxies around high redshift quasars . although it has been suggested that these objects belong to clusters or groups which are physically associated to the quasars ( @xcite ; @xcite ) , in order to be detected at such high redshifts they should be undergoing strong luminosity evolution . this seems unlikely on the light of the recent data on galaxy evolution obtained through the study of absorption - selected galaxy samples ( @xcite ) , which shows that the most plausible ( and often the unique ) interpretation for many of these observations is the existence of a magnification bias caused by gravitational lensing ( see the reviews @xcite ; @xcite ; @xcite ) . the density of a population of flux - limited background sources ( e.g. qsos ) behind a gravitational lens is affected by the lens magnification @xmath4 in two opposite ways .. Please generate the next two sentences of the article

one of the effects is purely geometrical : as the angular dimensions of a lensed patch of the sky are expanded by a factor @xmath4 , the physical size of a region observed through a fixed angular aperture will be smaller than in the absence of the lens . because of this , the qso surface density will decrease by a factor @xmath4 with respect to the unlensed background density @xcite ) . on the other hand , the lens will magnify faint quasars ( which would not have been detected otherwise ) into the sample and increase the number of detected qsos ( @xcite ; @xcite , etc . ) .

Suppose that you have an abstract for a scientific paper: the order of the coulomb - higgs transition in the u(1)-higgs model with unfrozen modulus of the scalar field is studied . large lattices ( up to @xmath0 in one case ) and high statistics are used . we fix @xmath1 and explore specially a region of @xmath2-values where metastability is observed . we study the thermodynamical limit of several observables , in particular , the latent heat , the specific heat , the decrement of the free energy between the maxima and the central minimum of the two - peaked histogram , the binder cumulant and the displacement of the critical coupling with the lattice size . the results point towards a second order transition for @xmath3 , while for smaller values of @xmath2 the strong metastability growing with the lattice size seems to derive from a first order character . _ a ) _ departamento de fsica terica , facultad de ciencias , + universidad de zaragoza , 50009 zaragoza , spain + _ b ) _ departamento de fsica terica i , facultad de ciencias fsicas , + universidad complutense de madrid , 28040 madrid , spain + _ key words : _ lattice . monte carlo . u(1 ) . higgs . phase transition . pacs : _ 14.80.bn , 11.15.ha . And you have already written the first three sentences of the full article: the higgs mechanism is an essential part of the present day formulation of the standard model . the u(1 ) gauge model coupled to scalars is a simplification of the gauge higgs sector of the sm , which keeps the unsolved problem of defining non perturbatively a non asymptotically free field theory .. Please generate the next two sentences of the article

the u(1)-higgs model has been widely studied previously . one of the main objectives has been to determine the order of the coulomb - higgs transition , both in the cases of frozen and unfrozen modulus of the scalar field , by using analytical ( mean field , one - loop effective potential , etc ) and numerical techniques ( see @xcite and references therein ) . from those analyses

Suppose that you have an abstract for a scientific paper: the arecibo l - band feed array zone of avoidance ( alfa zoa ) survey has discovered a nearby galaxy , alfa zoa j1952 + 1428 , at a heliocentric velocity of + 279 @xmath0 . the galaxy was discovered at low galactic latitude by 21-cm emission from neutral hydrogen ( h ) . we have obtained follow - up observations with the evla and the 0.9-m sara optical telescope . the h distribution overlaps an uncataloged , potential optical counterpart . the h linear size is 1.4 kpc at our adopted distance of d = 7 mpc , but the distance estimate is uncertain as hubble s law is unreliable at low recessional velocities . the optical counterpart has m@xmath1 = 16.9 mag and @xmath2 - @xmath3 = 0.1 mag . these characteristics , including m@xmath4 = 10@xmath5 m@xmath6 and @xmath7 = @xmath8 l@xmath6 , if at 7 mpc , indicate that this galaxy is a blue compact dwarf , but this remains uncertain until further follow - up observations are complete . optical follow - up observations are ongoing and near infrared follow - up observations have been scheduled . . And you have already written the first three sentences of the full article: the arecibo l - band feed array zone of avoidance ( alfa zoa ) survey searches for 21-cm line emission from neutral hydrogen ( h ) in galaxies behind the disk of the milky way . the survey uses the alfa receiver on the 305-m arecibo radio telescope . this region of the sky is termed the zone of avoidance by extragalactic astronomers because of its low galaxy detection rate .. Please generate the next two sentences of the article

extragalactic observations at visual wavelengths struggle with high extinction levels . near and far infrared observations suffer confusion with galactic stars , dust , and gas .

Suppose that you have an abstract for a scientific paper: the casimir - polder and van der waals interactions between an atom and a flat cavity wall are investigated under the influence of real conditions including the dynamic polarizability of the atom , actual conductivity of the wall material and nonzero temperature of the wall . the cases of different atoms near metal and dielectric walls are considered . it is shown that to obtain accurate results for the atom - wall interaction at short separations , one should use the complete tabulated optical data for the complex refractive index of the wall material and the accurate dynamic polarizability of an atom . at relatively large separations in the case of a metal wall , one may use the plasma model dielectric function to describe the dielectric properties of wall material . the obtained results are important for the theoretical interpretation of experiments on quantum reflection and bose - einstein condensation . [ [ section ] ] recently the study of dispersion interactions between an atom and a wall has assumed a new significance in connection with bose - einstein condensates of ultracold atoms [ 13 ] . the van der waals and casimir - polder forces acting between dilute individual atoms , confined in a magnetic trap , and a wall may influence the stability of a condensate and the effective size of the trap @xcite . as was shown in ref . @xcite , the study of the collective oscillations of the bose - einstein condensate can provide a sensitive test of dispersion forces . this prediction was later supported both theoretically @xcite and experimentally @xcite . dispersion interaction between an atom and a wall is also taken into account in quantum reflection of cold atoms on a surface @xcite and in dynamical interaction effects of fast atoms and molecules with solid surfaces @xcite . currently the new asymptotic behavior of the surface - atom interaction out of thermal equilibrium has been advanced @xcite . below we use the generic name casimir - polder " for all atom - wall.... And you have already written the first three sentences of the full article: itamp is supported in part by a grant from the nsf to the smithsonian institution and harvard university . vmm and glk were partially supported by faperj ( proceess nos . e26/170.132 and 170.409/2004 ) and by the russian foundation for basic research ( grant no .. Please generate the next two sentences of the article

050818119a ) . harber d m , mcguirk j m , obrecht j m and cornell e a 2003 _ j. low temp .

Suppose that you have an abstract for a scientific paper: we report on a theoretical study of the electronic interface reconstruction ( eir ) induced by polarity discontinuity at a heterojunction between a polar and a nonpolar mott insulators , and of the two - dimensional strongly - correlated electron systems ( 2dscess ) which accompany the reconstruction . we derive an expression for the minimum number of polar layers required to drive the eir , and discuss key parameters of the heterojunction system which control 2dsces properties . the role of strong correlations in enhancing confinement at the interface is emphasized . . And you have already written the first three sentences of the full article: two - dimensional ( 2d ) electron systems have been a fertile source of interesting physics over the past few decades , playing host to the fractional and integer quantum hall effects and cuprate superconductivity among other phenomena . the most widely studied and most thoroughly understood 2d electron systems are those that occur near semiconductor heterojunctions . in these systems carrier densities and disorder strengths can be adjusted using modulation doping and the electric field effect , and high sample quality can be achieved using lattice matched materials and epitaxial growth techniques .. Please generate the next two sentences of the article

these 2d systems are well described by fermi liquid theory , at least at magnetic field @xmath0 . rapid recent progress in the epitaxial growth of complex transition - metal oxides@xcite foreshadows the birth of an entirely new class of 2d electron systems , one in which electronic correlations are strong even at @xmath0 and non - fermi - liquid behavior is common .

Suppose that you have an abstract for a scientific paper: we show that resonant dipole - dipole interactions between rydberg atoms in a triangular lattice can give rise to artificial magnetic fields for spin excitations . we consider the coherent dipole - dipole coupling between @xmath0 and @xmath1 rydberg states and derive an effective spin-1/2 hamiltonian for the @xmath0 excitations . by breaking time - reversal symmetry via external fields we engineer complex hopping amplitudes for transitions between two rectangular sub - lattices . the phase of these hopping amplitudes depends on the direction of the hop . this gives rise to a staggered , artificial magnetic field which induces non - trivial topological effects . we calculate the single - particle band structure and investigate its chern numbers as a function of the lattice parameters and the detuning between the two sub - lattices . we identify extended parameter regimes where the chern number of the lowest band is @xmath2 or @xmath3 . . And you have already written the first three sentences of the full article: regular arrays of ultracold neutral atoms @xcite are a versatile tool for the quantum simulation @xcite of many - body physics @xcite . recent experimental progress allows one to control and observe atoms with single - site resolution @xcite which makes dynamical phenomena experimentally accessible in these systems . one promising perspective is to use this setup for investigating the rich physics of quantum magnetism @xcite and strongly correlated spin systems that are extremely challenging to simulate on a classical computer .. Please generate the next two sentences of the article

however , the simulation of magnetic phenomena with cold atoms faces two key challenges . first , neutral atoms do not experience a lorentz force in an external magnetic field . in order to circumvent this problem ,

Suppose that you have an abstract for a scientific paper: the influence of lorentz- and cpt - violating terms of the extended standard model on a semi - classical two - level system is analyzed . it is shown that the lorentz - violating background ( when coupled with the fermion sector in a vector way ) is able to induce modifications on the rabi oscillation pattern , promoting sensitive modulations on the usual oscillations . as for the term involving the coefficient coupled in an axial vector way , it brings about oscillations both on energy states and on the spin states ( implied by the background ) . it is also seen that such backgrounds are able to yield state oscillations even in the absence of the electromagnetic field . the foreseen effects are used to establish upper bounds on the lorentz - violating coefficients . . And you have already written the first three sentences of the full article: planck scale physics is an unknown frontier where gravitational and quantum effects are closely entwined . at this scale , it might occur that lorentz covariance is jeopardized . such kind of idea has caught much attention mainly after some authors argued the possibility of lorentz and cpt spontaneous breaking in the context of string theory @xcite .. Please generate the next two sentences of the article

the detection of lorentz violation at a lower energy scale , even minuscule , could be interpreted as a signature of spontaneous lorentz violation at the underlying theory ( defined at a higher energy scale ) . these * * remanent * * lorentz violating effects , inherited from a high energy theory , would be then employed to indicate possible features of a planck scale physics . * * the standard model extension ( sme ) @xcite is a broader version of the usual standard model that incorporates all lorentz - violating ( lv ) coefficients ( generated as vacuum expectation values of the underlying theory tensor quantities ) that yield lorentz scalars ( as tensor contractions ) in the observer frame .

Suppose that you have an abstract for a scientific paper: we propose an approach for multiple sequence alignment ( msa ) derived from the dynamic time warping viewpoint and recent techniques of curve synchronization developed in the context of functional data analysis . starting from pairwise alignments of all the sequences ( viewed as paths in a certain space ) , we construct a median path that represents the msa we are looking for . we establish a proof of concept that our method could be an interesting ingredient to include into refined msa techniques . we present a simple synthetic experiment as well as the study of a benchmark dataset , together with comparisons with 2 widely used msa softwares . \1 . departamento de estadstica , universidad carlos iii de madrid , c/ madrid , 126 - 28903 getafe , spain . e - mail : ana.arribas@uc3m.es + 2 . sorbonne universits , universit pierre et marie curie , universit paris diderot , centre national de la recherche scientifique , laboratoire de probabilits et modles alatoires , 4 place jussieu , 75252 paris cedex 05 , france . e - mail : catherine.matias@math.cnrs.fr _ key words and phrases : alignment ; dynamic time warping ; multiple sequence alignment ; warping _ + . And you have already written the first three sentences of the full article: multiple sequence alignment ( msa ) is one of the most fundamental tasks in bioinformatics . while there are many attempts to handle comparative sequence analyses without relying on msa , it still represents a starting point for most evolutionary biology methods . pairwise sequence alignment has been conceptualized as early as the 1970 s , starting with global alignments that attempt to align entire sequences @xcite and then introducing a decade later local alignments that focus on the identification of subsequences sharing high similarity @xcite .. Please generate the next two sentences of the article

the standard computational formulation of both tasks is to maximize a scoring function obtained as the sum of the score for each aligned pair of residues ( nucleotides or amino acids , the highest scores being attributed to pairs of residues with highest similarity ) , minus some gaps penalties . since these seminal works , an abundant literature has flourished exploring this topic in many different directions , from the pairwise problem to the more complex task of aligning more than 3 sequences ( one of the very first attempts appearing in * ? ? ?

Suppose that you have an abstract for a scientific paper: in 1982 , marshall p. tulin published a report proposing a framework for reducing the equations for gravity waves generated by moving bodies into a single nonlinear differential equation solvable in closed form [ _ proc . 14th symp . on naval hydrodynamics _ , 1982 , pp.1951 ] . several new and puzzling issues were highlighted by tulin , notably the existence of weak and strong wave - making regimes , and the paradoxical fact that the theory seemed to be applicable to flows at low speeds , _ but not too low speeds"_. these important issues were left unanswered , and despite the novelty of the ideas , tulin s report fell into relative obscurity . now thirty years later , we will revive tulin s observations , and explain how an asymptotically consistent framework allows us to address these concerns . most notably , we will explain , using the asymptotic method of steepest descents , how the production of free - surface waves can be related to the arrangement of integration contours connected to the shape of the moving body . this approach provides an intuitive and visual procedure for studying nonlinear wave - body interactions . surface gravity waves , wave - structure interactions , waves / free - surface flows . And you have already written the first three sentences of the full article: the motivation for this paper stems from an important , but seemingly forgotten 1982 report by prof . marshall p. tulin presented during the @xmath0 symposium on naval hydrodynamics , titled _ an exact theory of gravity wave generation by moving bodies , its approximation and its implications _ some thirty years after its publication , tulin wrote of his original motivation for pursuing the former study : _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ what were the relations and connections among these various nonlinear approximations . Please generate the next two sentences of the article

ray , slow ship , " , second order , formal straining , and guilloton that had arisen by the end of the 1970s ? [ ... ] i had earlier in the 1970s become intrigued by the davies transformation of the nonlinear free - surface problem , which was revealed in milne - thompson s legendary banquet speech [ in 1956 ] . my hope was that my extension of the davies theory would provide an exact result in analytical form , which even in its complexity could then be subject to various approximations , the connections of which could thereby be discerned .

Suppose that you have an abstract for a scientific paper: w28 is one of the archetype supernova remnants ( snrs ) interacting with molecular clouds . h.e.s.s . observation found four tev sources which are coincident with the molecular clouds ( mcs ) around w28 , but _ fermi _ lat detected no prominent gev counterparts for two of them . an accumulative diffusion model is established in this letter and the energetic protons colliding the nearby mcs are considered to be an accumulation of the diffusive protons escaping from the shock front throughout the history of the snr expansion . we have fitted the @xmath0-ray spectra of the four sources and naturally explained the gev spectral break of the northeastern source ( source n ) and the nonsignificant gev emission of the southern sources a and c. the distances of sources a and c from the snr centre are found to be much larger than those of sources n and b , which may be the basic reason for the faint gev @xmath0-rays of the two former sources . [ firstpage ] radiation mechanisms : non - thermal gamma rays : theory ism : supernova remnants . . And you have already written the first three sentences of the full article: cosmic rays ( crs ) below the knee " in the galaxy are commonly believed to be accelerated at the shock of supernova remnants ( snrs ) . however , whether the @xmath0-rays from snrs are of hadronic or leptonic origin is still in hot debate . although evidences for @xmath0-ray emission arising from molecular clouds ( mcs ) have been found in two snrs , ic 443 ( acciari et al . 2009 ) and w28 ( aharonian et al .. Please generate the next two sentences of the article

2008 ) , it is not easy yet to confirm the emission of the accelerated protons , since the competing lepton processes can also account for the high energy radiation . fortunately , emission from mcs illuminated by crs from nearby snrs ( aharonian & atoyan 1996 ; gabici et al.2009 ) can give us opportunities not only to distinguish the contribution of the hadrons from that of leptons but also to investigate the escape process of these energetic protons ( fujita et al.2009 ) . snr w28 , with recent observation in gev and tev @xmath0-rays , is such an excellent case .

Suppose that you have an abstract for a scientific paper: we present a master formula , with applicability conditions , which allows us to automate the resummation of infrared and collinear logarithms appearing in distributions of jet observables in qcd at next - to - leading logarithmic accuracy . . And you have already written the first three sentences of the full article: jet observables , event shapes and jet rates , revealed themselves as one of the richest laboratories to explore qcd . being infrared and collinear safe ( irc ) , they can be predicted with perturbative ( pt ) techniques , but their high sensitivity to low energy emissions allows us to investigate the fairly unknown non - perturbative regime . most discriminatory studies make use of distributions . in integrated distributions. Please generate the next two sentences of the article

@xmath0 one requires that the value of the observable @xmath1 a function of all secondary final state momenta @xmath2 and of the born momenta after recoil from the emissions @xmath3 be less than a fixed value @xmath4 @xmath5 the inclusive phase space region , where @xmath6 , is dominated by events with hard jets , which move the value of the observable far away from its born value , @xmath7 . these events can be described with fixed order pt expansions , however they are quite rare , every additional jet being suppressed by an additional factor of @xmath8 .

Suppose that you have an abstract for a scientific paper: the hypothesis of a pevatron in the galactic center , emerged with the recent @xmath0-ray measurements of h.e.s.s . @xcite , motivates the search for neutrinos from this source . the effect of @xmath0-ray absorption is studied : at the energies currently probed , the known background radiation fields lead to small effects , whereas it is not possible to exclude large effects due to new ir radiation fields near the very center . precise upper limits on neutrino fluxes are derived and the underlying hypotheses are discussed . the expected number of events for antares , icecube and km3net , based on the h.e.s.s . measurements , are calculated . it is shown that km@xmath1-class telescopes in the northern hemisphere have the potential of observing high - energy neutrinos from this important astronomical object and can check the existence of a hadronic pev galactic accelerator . . And you have already written the first three sentences of the full article: the supermassive black - hole in the center of the milky way , located in the radio source sgr a * , is one of the most interesting astronomical objects : see ref . @xcite for an extensive review . it is now in a state of relative inactivity @xcite but there is no good reason for it to be stationary .. Please generate the next two sentences of the article

e.g. , there are interesting hints for a much stronger emission few 100 years ago @xcite ; on the time scale of 40,000 years , major variability episodes are expected @xcite ; fermi bubbles @xcite could be visible manifestations @xcite of its intense activity . therefore , it is reasonable to expect that a past emission from the galactic center leads to observable effects . such scenario was recently considered in ref .

Suppose that you have an abstract for a scientific paper: in the cdm cosmological framework structures grow from merging with smaller structures . merging should have observable effects on galaxies including destroying disks and creating spheroids . this proceeding aims to give a brief overview of how mergers occur in cosmological simulations . in this regard it is important to understand that dark matter halo mergers are not galaxy mergers ; a theory of galaxy formation is necessary to connect the two . mergers of galaxies in hydrodynamical simulations show a stronger dependence on mass than halo mergers in n - body simulations . if one knows how to connect galaxies to dark matter halos then the halo merger rate can be converted into a galaxy merger rate . when this is done it becomes clear that major mergers are many times more common in more massive galaxies offering a possible explanation of why hubble type depends on galaxy mass . . And you have already written the first three sentences of the full article: structure growth via mergers is one of the main predictions of cdm type cosmologies . however , what is predicted is the merger rates of dark matter halos , which are not directly observable . using dark matter halo merger rates to predict galaxy merger rates requires a theory of galaxy formation or at least a model of how galaxies populate dark matter halos . in a similar way ,. Please generate the next two sentences of the article

what can actually be observed are close galaxy pairs , disturbed galaxies , or morphological differences between galaxies , all of which can only be indirectly tied to galaxy mergers using theoretical models . thus connecting theory to observations poses a number of difficulties which are often not given enough attention .

Suppose that you have an abstract for a scientific paper: in this paper , we investigate the microscopic dynamics of a polymer of length @xmath0 translocating through a narrow pore . characterization of its purportedly anomalous dynamics has so far remained incomplete . we show that the polymer dynamics is anomalous until the rouse time @xmath1 , with a mean square displacement through the pore consistent with @xmath2 , with @xmath3 the flory exponent . this is shown to be directly related to a decay in time of the excess monomer density near the pore as @xmath4 . beyond the rouse time translocation becomes diffusive . in consequence of this , the dwell - time @xmath5 , the time a translocating polymer typically spends within the pore , scales as @xmath6 , in contrast to previous claims . . And you have already written the first three sentences of the full article: transport of molecules across cell membranes is an essential mechanism for life processes . these molecules are often long and flexible , and the pores in the membranes are too narrow to allow them to pass through as a single unit . in such circumstances , the passage of a molecule through the pore i.e. its translocation proceeds through a random process in which polymer segments sequentially move through the pore . dna , rna and proteins are naturally occurring long molecules @xcite subject to translocation in a variety of biological processes .. Please generate the next two sentences of the article

translocation is used in gene therapy @xcite , in delivery of drug molecules to their activation sites @xcite , and as an efficient means of single molecule sequencing of dna and rna @xcite . understandably , the process of translocation has been an active topic of current research : both because it is an essential ingredient in many biological processes and for its relevance in practical applications .

Suppose that you have an abstract for a scientific paper: social contact networks underlying epidemic processes in humans and animals are highly dynamic . the spreading of infections on such temporal networks can differ dramatically from spreading on static networks . we theoretically investigate the effects of concurrency , the number of neighbors that a node has at a given time point , on the epidemic threshold in the stochastic susceptible - infected - susceptible dynamics on temporal network models . we show that network dynamics can suppress epidemics ( i.e. , yield a higher epidemic threshold ) when nodes concurrency is low , but can also enhance epidemics when the concurrency is high . we analytically determine different phases of this concurrency - induced transition , and confirm our results with numerical simulations . _ introduction : _ social contact networks on which infectious diseases occur in humans and animals or viral information spreads online and offline are mostly dynamic . switching of partners and ( usually non - markovian ) activity of individuals , for example , shape network dynamics on such temporal networks @xcite . better understanding of epidemic dynamics on temporal networks is needed to help improve predictions of , and interventions in , emergent infectious diseases , to design vaccination strategies , and to identify viral marketing opportunities . this is particularly so because what we know about epidemic processes on static networks @xcite is only valid when the timescales of the network dynamics and of the infectious processes are well separated . in fact , temporal properties of networks , such as long - tailed distributions of inter - contact times , temporal and cross - edge correlation in inter - contact times , and entries and exits of nodes , considerably alter how infections spread in a network @xcite . in the present study , we focus on a relatively neglected component of temporal networks , i.e. , the number of concurrent contacts that a node has . even if two temporal networks are the.... And you have already written the first three sentences of the full article: ) by @xmath119 @xcite . the lines represent the numerical results for the delta function ( i.e. , all nodes have same activity potential ) and power - law activity distributions . the arrows indicate @xmath74^{-1}$ ] .. Please generate the next two sentences of the article

we set @xmath120 and @xmath121.,width=326 ] we consider sis dynamics on a star graph with @xmath7 leaves and derive @xmath23 , @xmath25 , @xmath31 , @xmath32 , and @xmath33 .

Suppose that you have an abstract for a scientific paper: we investigate the effects of quantum gravity on the planck era of the universe . in particular , using different versions of the generalized uncertainty principle and under specific conditions we find that the main planck quantities such as the planck time , length , mass and energy become larger by a factor of order @xmath0 compared to those quantities which result from the heisenberg uncertainty principle . however , we prove that the dimensionless entropy enclosed in the cosmological horizon at the planck time remains unchanged . these results , though preliminary , indicate that we should anticipate modifications in the set - up of cosmology since changes in the planck era will be inherited even to the late universe through the framework of quantum gravity ( or quantum field theory ) which utilizes the planck scale as a fundamental one . more importantly , these corrections will not affect the entropic content of the universe at the planck time which is a crucial element for one of the basic principles of quantum gravity named holographic principle . . And you have already written the first three sentences of the full article: gravity is a universal and fundamental force . anything which has energy creates gravity and is affected by it , although the smallness of newton s constant @xmath1 often means that the associated classical effects are too weak to be measurable . an important prediction of various theories of quantum gravity ( such as string theory ) and black hole physics is the existence of a minimum measurable length @xcite .. Please generate the next two sentences of the article

the prediction is largely model - independent , and can be understood as follows : the heisenberg uncertainty principle ( hup ) , @xmath2 , breaks down for energies close to the planck scale , when the corresponding schwarzschild radius is comparable to the compton wavelength ( both being approximately equal to the planck length ) . higher energies result in a further increase of the schwarzschild radius , resulting in @xmath3 . at this point

Suppose that you have an abstract for a scientific paper: we study the velocity structure of penumbral filaments in the deep photosphere to obtain direct evidence for the convective nature of sunspot penumbrae . a sunspot was observed at high spatial resolution with the 1-m swedish solar telescope in the deep photospheric c@xmath0i5380 absorption line . the multi - object multi - frame blind deconvolution ( momfbd ) method is used for image restoration and straylight is filtered out . we report here the discovery of clear redshifts in the c@xmath0i5380 line at multiple locations in sunspot penumbral filaments . for example , bright head of filaments show larger concentrated blueshift and are surrounded by darker , redshifted regions , suggestive of overturning convection . elongated downflow lanes are also located beside bright penumbral fibrils . our results provide the strongest evidence yet for the presence of overturning convection in penumbral filaments and highlight the need to observe the deepest layers of the penumbra in order to uncover the energy transport processes taking place there . . And you have already written the first three sentences of the full article: in recent years , indirect evidence for the presence of convection in sunspot penumbral filaments has been growing ( e.g. , scharmer 2009 ) . e.g. , the twisting motion of penumbral filaments is taken as a signature of overturning convection ( ichimoto et al . 2007 ; zakharov et al . 2008 ; spruit et al . 2010 ; bharti et al . 2010 ) . using high resolution spectropolarimetric observations ,. Please generate the next two sentences of the article

zakharov et al . ( 2008 ) estimated that such motions can provide sufficient heat to the surface layers of the penumbra to explain its relatively high brightness . the correlation of the apparent velocity of the twisting motion with the local brightness of the filaments obtained by bharti et al .

Suppose that you have an abstract for a scientific paper: the laplacian gauge is a nonperturbative gauge fixing that reduces to landau gauge in the asymptotic limit . like landau gauge , it respects lorentz invariance , but it is free of gribov copies ; the gauge fixing is unambiguous . in this paper we study the infrared behavior of the lattice gluon propagator in laplacian gauge by using a variety of lattices with spacings from @xmath0 to 0.35 fm , to explore finite volume and discretization effects . three different implementations of the laplacian gauge are defined and compared . the laplacian gauge propagator has already been claimed to be insensitive to finite volume effects and this is tested on lattices with large volumes . . And you have already written the first three sentences of the full article: the lattice provides a useful tool for studying the gluon propagator because it is a first principles treatment that can , in principle , access any momentum window . there is tremendous interest in the infrared behavior of the gluon propagator as a probe into the mechanism of confinement @xcite and lattice studies focusing on its ultraviolet behavior have been used to calculate the running qcd coupling @xcite . such studies can also inform model hadron calculations @xcite .. Please generate the next two sentences of the article

although there has recently been interest in coulomb gauge @xcite and generic covariant gauges @xcite , the usual gauge for these studies has been landau gauge , because it is a ( lattice ) lorentz covariant gauge that is easy to implement on the lattice , and its popularity means that results from the lattice can be easily compared to studies that use different methods . finite volume effects and discretization errors have been extensively explored in lattice landau gauge @xcite .

Suppose that you have an abstract for a scientific paper: it is believed that most giant elliptical galaxies possess nuclear black holes with masses in excess of @xmath0 . bondi accretion from the interstellar medium might then be expected to produce quasar - like luminosities from the nuclei of even quiescent elliptical galaxies . it is a puzzle that such luminosities are _ not observed_. motivated by this problem , fabian & rees have recently suggested that the final stages of accretion in these objects occurs in an advection - dominated mode with a correspondingly small radiative efficiency . despite possessing a long - known active nucleus and dynamical evidence for a black hole , the low radiative and kinetic luminosities of the core of m87 provide the best illustration of this problem . we examine an advection - dominated model for the nucleus of m87 and show that accretion at the bondi rate is compatible with the best known estimates for the core flux from radio through to x - ray wavelengths . the success of this model prompts us to propose that fr - i radio galaxies and quiescent elliptical galaxies accrete in an advection dominated mode whereas fr - ii type radio - loud nuclei possess radiatively efficient thin accretion disks . ps . # 1to 0pt#1 galaxies : individual : m87 , galaxies : active , accretion , accretion discs . And you have already written the first three sentences of the full article: there is strong evidence that most giant elliptical galaxies should possess nuclear supermassive black holes , relics of an earlier quasar phase . quasar counts and integrated luminosities suggest masses above @xmath1 @xmath2 . given this fact , there is a major puzzle surrounding quiescent giant ellipticals which was first illuminated by fabian & canizares ( 1988 ) .. Please generate the next two sentences of the article

a massive black hole in the centre of an elliptical galaxy would accrete from the interstellar medium ( which forms a hot hydrostatic atmosphere in the potential well of the galaxy ) . the accretion rate would be expected to be at least that given by bondi s spherical accretion formula ( bondi 1952 ) .

Suppose that you have an abstract for a scientific paper: we analyze spacetime momentum currents on a classical string worldsheet , study their generic connection via ads / cft correspondence to the instantaneous energy loss of the dual field theory degrees of freedom and suggest a general formula for computing energy loss in a time - dependent string configuration . applying this formula to the case of falling strings , generally dual to light quarks , reveals that the energy loss does not display a well - pronounced bragg peak at late times , as previously believed . finally , we comment on the possible implications of this result to the jet quenching phenomena in heavy ion collisions . . And you have already written the first three sentences of the full article: gauge / gravity duality has been a very insightful tool used to study many properties of strongly coupled non - abelian plasmas , especially after many indications that the quark - gluon plasma created in heavy ion collisions at the rhic collider is a strongly coupled system @xcite . the ads / cft correspondence @xcite is a duality between a ( 3 + 1)-dimensional @xmath0 @xmath1 super - yang - mills ( sym ) gauge theory and type iib string theory on @xmath2 spacetime . using this conjecture and by taking the limit @xmath3 , one can study this gauge theory at strong coupling by studying classical , two - derivative ( super)gravity . due to phenomenological differences between thermal @xmath0 sym plasma and finite - temperature qcd , it is important to consider gravity duals to nonconformal gauge theories @xcite .. Please generate the next two sentences of the article

however , since the information about the medium ( on the field theory side ) is fully encoded in the spacetime metric ( on the string side ) , in this work we will keep our results as general as possible by considering a general metric @xmath4 and only use the @xmath5 metric for final numerical evaluations . in recent years , an important application of the ads / cft correspondence has been to study the phenomenon of jet quenching @xcite in strongly coupled systems , especially after the pioneering work of @xcite and @xcite , who studied energy loss of heavy quarks in a strongly coupled @xmath0 sym plasma . to study the plasma at a finite temperature @xmath6 ,

Suppose that you have an abstract for a scientific paper: recent claims of a gamma - ray excess in the diffuse galactic emission detected by the fermi large area telescope made use of spatial templates from the interstellar medium ( ism ) column density and the 408 mhz sky as proxies for neutral pion and inverse compton ( ic ) gamma - ray emission , respectively . we identify significant systematic effects in this procedure that can artificially induce an additional diffuse component with a morphology strikingly similar to the claimed gamma - ray haze . to quantitatively illustrate this point we calculate sky - maps of the ratio of the gamma - ray emission from neutral pions to the ism column density , and of ic to synchrotron emission , using detailed galactic cosmic - ray models and simulations . in the region above and below the galactic center , the ism template underestimates the gamma - ray emission due to neutral pion decay by approximately 20% . additionally , the synchrotron template tends to under - estimate the ic emission at low energies ( few gev ) and to over - estimate it at higher energies ( tens of gev ) by potentially large factors that depend crucially on the assumed magnetic field structure of the galaxy . the size of the systematic effects we find are comparable to the size of the claimed `` fermi haze '' signal . we thus conclude that a detailed model for the galactic diffuse emission is necessary in order to conclusively assess the presence of a gamma - ray excess possibly associated to the wmap haze morphology . . And you have already written the first three sentences of the full article: one of the most exciting yet observationally challenging scientific objectives of the large area telescope ( lat ) on board the _ fermi gamma - ray space telescope _ @xcite , is the indirect detection of particle dark matter @xcite . however , limited gamma - ray statistics make diffuse signals arising from the pair - annihilation of dark matter difficult to differentiate from astrophysical processes .. Please generate the next two sentences of the article

the limitation of using a diffuse signal to search for non - standard emission stems from difficulties in controlling the instrumental background and formulating a rigorous model for the astrophysical diffuse foregrounds . an intriguing excess of microwave radiation in the wmap data has been uncovered by @xcite and @xcite .

Suppose that you have an abstract for a scientific paper: we show that all the singlet even - frequency , singlet odd - frequency , triplet even - frequency and triplet odd - frequency pairings , and together with the corresponding order parameters ( gaps ) can be realized in insb ( 110 ) spin - orbit - coupled quantum well in proximity to @xmath0-wave superconductor in fulde - ferrell - larkin - ovchinnikov phase or with a supercurrent . it is revealed that with the singlet even - frequency order parameter induced by the proximity effect , triplet even - frequency pairing is induced due to the broken spin - rotational symmetry by the spin - orbit coupling . since the translational symmetry is broken by the center - of - mass momentum of cooper pair in the fulde - ferrell - larkin - ovchinnikov phase or with a supercurrent , the singlet odd - frequency pairing can be induced . with the translational and spin - rotational asymmetries , the triplet odd - frequency pairing is also realized . then , we show that the corresponding order parameters can be obtained from the self - energy of the electron - electron coulomb interaction with the dynamic screening . the singlet and the induced triplet even - frequency order parameters are found to exhibit the conventional @xmath0-wave and @xmath1-wave characters in the momentum space , respectively . whereas for the induced odd - frequency order parameters in quantum well , the singlet and triplet ones show the @xmath1-wave and @xmath2-wave characters , respectively . moreover , the @xmath1-wave character of the singlet odd - frequency order parameter exhibits anisotropy with respect to the direction of the center - of - mass momentum . while for the triplet one , we find that @xmath3-wave and @xmath4-wave characters can be obtained with respect to the direction of the center - of - mass momentum . we show that at proper density , the singlet even - frequency order parameter is suppressed and the induced singlet odd - frequency , triplet even - frequency and triplet odd - frequency ones can be detected experimentally . . And you have already written the first three sentences of the full article: in the field of superconductivity , symmetry of the cooper - pair wavefunction in spin- , time- , and orbital - spaces has attracted much attention for the past few decades . within the framework of superconductivity theory developed by bardeen , cooper and schrieffer ( bcs),@xcite it is established that a cooper pair is formed by two electrons with momentums @xmath5 and @xmath6 near the fermi surface . due to the fermi - dirac statistics , the cooper - pair wavefunction must have sign change in the exchange of the two electrons . in the spin space , cooper pair can be classified into either singlet or triplet type . as for the orbital part of the pair wavefunction ,. Please generate the next two sentences of the article

when we focus on the symmetry with respect to the exchange of two momentums @xmath5 and @xmath6 , i.e. , @xmath7 , one can define the parity of the cooper pair . for the conventional bcs superconductors like al , pb and nb , in the presence of the translational symmetry ( @xmath8 ) and together with the space- , time - inversion and spin - rotational symmetries , the cooper pairs are in the singlet even - frequency even - parity state , in consistent with the fermi - dirac statistics . here , even / odd frequency refers to the situation that the pair wavefunction is even / odd with respect to the exchange of time coordinates . in 1974 , berezinskii considered the possibility of the triplet even - frequency pairing with even parity in the observed phase of @xmath9he.@xcite after that , the possibilities of the cooper pair with other symmetries are extensively studied , and from the symmetry analysis,@xcite cooper pairs can be classified into ( i ) singlet even - frequency ( se ) with even parity ; ( ii ) singlet odd - frequency ( so ) with odd parity ; ( iii ) triplet odd - frequency ( to ) with even parity ; ( iv ) triplet even - frequency ( te ) with odd parity . specifically , after the proposal by berezinskii , to pairing has been discussed in a wide variety of theoretical models with spin - rotational and time - inversion asymmetries,@xcite e.g. , kondo model,@xcite hubbard model@xcite and heavy fermion system.@xcite meanwhile , several proposals about the so pairing have also been reported in the inhomogeneous systems with space- and time - inversion asymmetries by introducing effective @xmath1-wave electron - electron ( e - e ) interaction.@xcite in the presence of the odd - frequency pairings , by considering the retardation effect of the electron interaction , odd - frequency gaps or odd - frequency order parameters are theoretically suggested.@xcite however , up till now , odd - frequency bulk superconductor has not yet been realized experimentally .

Suppose that you have an abstract for a scientific paper: the complexity of computing the lempel - ziv factorization and the set of all runs (= maximal repetitions ) is studied in the decision tree model of computation over ordered alphabet . it is known that both these problems can be solved by ram algorithms in @xmath0 time , where @xmath1 is the length of the input string and @xmath2 is the number of distinct letters in it . we prove an @xmath3 lower bound on the number of comparisons required to construct the lempel - ziv factorization and thereby conclude that a popular technique of computation of runs using the lempel - ziv factorization can not achieve an @xmath4 time bound . in contrast with this , we exhibit an @xmath5 decision tree algorithm finding all runs in a string . therefore , in the decision tree model the runs problem is easier than the lempel - ziv factorization . thus we support the conjecture that there is a linear ram algorithm finding all runs . . And you have already written the first three sentences of the full article: string repetitions called runs and the lempel - ziv factorization are structures that are of a great importance for data compression and play a significant role in stringology . recall that a run of a string is a nonextendable ( with the same minimal period ) substring whose minimal period is at most half of its length . the definition of the lempel - ziv factorization is given below . in the decision tree model , a widely used model to obtain lower bounds on the time complexity of various algorithms , we consider algorithms finding these structures . we prove that any algorithm finding the lempel - ziv factorization on a general ordered alphabet must perform @xmath3 denotes the logarithm with the base @xmath6 .. Please generate the next two sentences of the article

] comparisons in the worst case , where @xmath1 denotes the length of input string and @xmath2 denotes the number of distinct letters in it . since until recently , the only known efficient way to find all runs of a string was to use the lempel - ziv factorization , one might expect that there is a nontrivial lower bound in the decision tree model on the number of comparisons in algorithms finding all runs . these expectations were also supported by the existence of such a bound in the case of unordered alphabet . in this paper

Suppose that you have an abstract for a scientific paper: key features of antiferromagnetic dynamical correlations in high-@xmath0 superconductors cuprates are discussed . in underdoped regime , the sharp resonance peak , occuring exclusively in the sc state , is accompanied by a broader contribution located around @xmath1 30 mev which remains above @xmath0 . their interplay may induce incommensurate structure in the superconducting state . . And you have already written the first three sentences of the full article: over the last decade , a great deal of effort has been devoted to show the importance of antiferromagnetic ( af ) dynamical correlations for the physical properties of high-@xmath0 cuprates and consequently for the microscopic mechanism responsible for superconductivity@xcite . to elucidate how these electronic correlations are relevant , it is then necessary to put the spectral weight of af fluctuations on a more quantitative scale . inelastic neutron scattering ( ins ) provides essential information on this matter as it directly measures the full energy and momentum dependences of the spin - spin correlation function .. Please generate the next two sentences of the article

recently , efforts have been made to determine them in absolute units by comparison with phonon scattering . the following definition , corresponding to @xmath2 of the total spin susceptibility , is used@xcite , @xmath3>\ ] ] our results are then directly comparable with both nuclear magnetic resonance ( nmr ) results and theoretical calculations . here , some aspects of the spin dynamics obtained in bilayer system will be presented in relation with recent results reported by other groups@xcite .

Suppose that you have an abstract for a scientific paper: we study the effect of marginal and irrelevant deformations on the renormalization of operators near a cft fixed point . new divergences in a given operator are determined by its ope with the operator @xmath0 that generates the deformation . this provides a scheme to compute the couplings @xmath1 between the operator @xmath0 and two arbitrary operators @xmath2 and @xmath3 . we exemplify for the case of @xmath4 sym , considering the simplest case of the exact lagrangian deformation . in this case the deformed anomalous dimension matrix is determined by the derivative of the anomalous dimension matrix with respect to the coupling . we use integrability techniques to compute the one - loop couplings @xmath5 between the lagrangian and two distinct large operators built with magnons , in the su(2 ) sector of the theory . then we consider @xmath6 at strong coupling , and show how to compute it using the gauge / gravity duality , when @xmath0 is a chiral operator dual to any supergravity field and @xmath2 is dual to a heavy string state . we exemplify for the lagrangian and operators @xmath2 dual to heavy string states , showing agreement with the prediction derived from the renormalization group arguments . miguel s. costa@xmath7 , ricardo monteiro@xmath8 , jorge e. santos@xmath8 , dimitrios zoakos@xmath7 + _ @xmath9 centro de fsica do porto + departamento de fsica e astronomia + faculdade de cincias da universidade do porto + rua do campo alegre 687 , 4169007 porto , portugal _ + _ @xmath10damtp , centre for mathematical sciences + university of cambridge + wilberforce road , cambridge cb3 0wa , uk _ . And you have already written the first three sentences of the full article: to solve a conformal field theory ( cft ) amounts to finding its spectrum and 3-point correlation functions , since higher point functions may be obtained using the operator product expansion ( ope ) . in the former case this means finding the anomalous dimensions of the operators of the theory , while in the latter case it means finding the couplings in 3-point correlation functions , whose space - time dependence is otherwise fixed by conformal invariance . in the simplest case of scalar primary operators the 3-point function has the simple form _ a(0)o_b(x)o_c(y)= . where @xmath11 is the dimension of the operator @xmath2 , and so on .. Please generate the next two sentences of the article

the definition of the couplings @xmath12 requires that the operators diagonalise the anomalous dimension matrix and depends on the choice of normalisation in the 2-point function of each operator . our main interest is to explore new methods to compute the couplings @xmath12 for certain single trace operators in @xmath4 sym . in recent years

Suppose that you have an abstract for a scientific paper: in this article we carry out an analysis of lhc potential to search for new dimuon resonance states from extended gauge models and the randall - sundrum scenario of tev - scale gravity . * search for new heavy resonances at the lhc * + i. golutvin , , m. savina , s. shmatov + jonit institute for nuclear research , dubna , russia + . And you have already written the first three sentences of the full article: the standard model ( sm ) had been tested in many experiments at lep , slc and tevatron with a high accuracy . in particular , the yield of lepton pairs produced mainly via drell - yan processes , i.e. quark - antiquark annihilation by exchange of photons or z bosons , is predicted by the sm with a per mille precision . so far , the experimental data have shown no significant deviations from sm predictions for the drell - yan continuum up to tev - energy - scale .. Please generate the next two sentences of the article

the high - order calculations of lepton pair production cross section in the mass region of @xmath0 tev/@xmath1 are in good agreement with lep and d0 data @xcite . at present , however , there are many theoretical attempts to extend the bounds of the sm in order to reach unification of strong and electroweak interactions or remove an arbitrariness in values of coupling constants in some other way and also to pull through known disadvantages of sm like the mass hierarchy problem , cp - violation problem etc . supersymmetry is the most popular theoretical extension of the sm , however , some other alternatives also exist . between them

Suppose that you have an abstract for a scientific paper: an embedding scheme is developed for the dirac hamiltonian @xmath0 . dividing space into regions i and ii separated by surface @xmath1 , an expression is derived for the expectation value of @xmath0 which makes explicit reference to a trial function defined in i alone , with all details of region ii replaced by an effective potential acting on @xmath1 and which is related to the green function of region ii . stationary solutions provide approximations to the eigenstates of @xmath0 within i. the green function for the embedded hamiltonian is equal to the green function for the entire system in region i. application of the method is illustrated for the problem of a hydrogen atom in a spherical cavity and an au(001)/ag / au(001 ) sandwich structure using basis sets that satisfy kinetic balance . . And you have already written the first three sentences of the full article: there are many problems concerning electronic structure where attention is focussed on a small region of a larger system , at surfaces or defects in crystals being perhaps the most common . let us call this region i , figure [ fig:1 ] , and the rest of the system region ii . although not of primary interest region ii can not be ignored , since in general the electron wave functions in i will be sensitive to the contents of region ii .. Please generate the next two sentences of the article

some time ago inglesfield @xcite derived an embedding scheme which enables the single - particle schrdinger equation to be solved explicitly only in region i. the influence of region ii is taken into account exactly by adding an energy - dependent non - local potential to the hamiltonian for region i , which constrains the solutions in i to match onto solutions in ii . this embedding method has been developed into a powerful tool most notably for surface electronic structure problems @xcite where it has found widespread application especially to situations where an accurate description of the spectrum of electron states is necessary .

Suppose that you have an abstract for a scientific paper: we present a highly complete and reliable mid - infrared ( mir ) colour selection of luminous agn candidates using the 3.4 , 4.6 , and 12 @xmath0 m bands of the @xmath1 survey . the mir colour wedge was defined using the wide - angle bright ultra - hard _ xmm - newton _ survey ( buxs ) , one of the largest complete flux - limited samples of bright ( @xmath2 ) `` ultra - hard '' ( 4.5 - 10 kev ) x - ray selected agn to date . buxs includes 258 objects detected over a total sky area of 44.43 deg@xmath3 of which 251 are spectroscopically identified and classified , with 145 being type-1 agn and 106 type-2 agn . our technique is designed to select objects with red mir power - law spectral energy distributions ( sed ) in the three shortest bands of @xmath1 and properly accounts for the errors in the photometry and deviations of the mir seds from a pure power - law . the completeness of the mir selection is a strong function of luminosity . at @xmath4 , where the agn is expected to dominate the mir emission , @xmath5 and @xmath6 of the ` buxs ` type-1 and type-2 agn meet the selection . our technique shows one of the highest reliability and efficiency of detection of the x - ray selected luminous agn population with @xmath1 amongst those in the literature . in the area covered by the ` buxs ` survey our selection identifies 2755 agn candidates detected with snr@xmath75 in the three shorter wavelength bands of wise with 38.5% having a detection at 2 - 10 kev x - ray energies . we also analyzed the possibility of including the 22@xmath0 m @xmath1 band to select agn candidates , but neither the completeness nor the reliability of the selection improves . this is likely due to both the significantly shallower depth at 22@xmath0 m compared with the first three bands of @xmath1 and star - formation contributing to the 22@xmath0 m emission at the @xmath1 22@xmath0 m sensitivity . [ firstpage ] galaxies : active - quasars : general - infrared : galaxies . And you have already written the first three sentences of the full article: there is strong observational evidence that active galactic nuclei ( agn ) play an important role in the formation and growth of galaxies ( e.g. @xcite ) . most supermassive black hole growth takes place during an obscured quasar phase , as suggested by the integrated energy density of the cosmic x - ray background @xcite . to understand the evolution of galaxies and to trace the energy output due to accretion and its cosmological evolution , it is critical to map the history of obscured accretion . x - ray surveys with _ xmm - newton _ and _ chandra _ at energies @xmath810 kev are sensitive to all but the most heavily obscured agn ( e.g. @xcite ) . in compton - thick agn ( rest - frame column densities exceeding @xmath9 ) the observed flux below 10 kev can be as low as a few % of the intrinsic nuclear flux . in the compton - thick regime the high energy photons that survive the photoelectric absorption get scattered in the absorber losing part of their energy ( compton down - scattering ) .. Please generate the next two sentences of the article

this is an important effect that can significantly suppress the transmitted continuum ( @xcite ; @xcite ; @xcite ) . the ongoing swift / bat and integral / ibis all - sky surveys at energies 15 - 200 kev are providing the least biased samples of absorbed agn in the local universe ( e.g. @xcite ; @xcite ; @xcite ; @xcite ) .

Suppose that you have an abstract for a scientific paper: there is some consensus among orthodox category theorists that the concept of adjoint functors is the most important concept contributed to mathematics by category theory . we give a heterodox treatment of adjoints using heteromorphisms ( object - to - object morphisms between objects of different categories ) that parses an adjunction into two separate parts ( left and right representations of heteromorphisms ) . then these separate parts can be recombined in a new way to define a cognate concept , the brain functor , to abstractly model the functions of perception and action of a brain . the treatment uses relatively simple category theory and is focused on the interpretation and application of the mathematical concepts . the mathematical appendix is of general interest to category theorists as it is a defense of the use of heteromorphisms as a natural and necessary part of category theory . . And you have already written the first three sentences of the full article: there is already a considerable but widely varying literature on the application of category theory to the life and cognitive sciences such as the work of robert rosen ( @xcite , @xcite ) and his followers as well as andre ehresmann and jean - paul vanbremeersch @xcite and their commentators . the approach taken here is based on a specific use of the characteristic concepts of category theory , namely universal mapping properties . one such approach in the literature is that of franois magnan and gonzalo reyes which emphasizes that `` category theory provides means to circumscribe and study what is universal in mathematics and other scientific disciplines . ''. Please generate the next two sentences of the article

their intended field of application is cognitive science . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ we may even suggest that universals of the mind may be expressed by means of universal properties in the theory of categories and much of the work done up to now in this area seems to bear out this suggestion .... by discussing the process of counting in some detail , we give evidence that this universal ability of the human mind may be conveniently conceptualized in terms of this theory of universals which is category theory . @xcite _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ another current approach that emphasizes universal mapping properties ( `` universal constructions '' ) is that of s. phillips , w. h. wilson , and g. s. halford ( @xcite , @xcite , @xcite ) . in addition to the focus on universals , the approach here is distinctive in the use of heteromorphisms which are object - to - object morphisms between objects if different categories in contrast to the usual homomorphisms or homs between objects in the same category . by explicitly adding heteromorphisms to the usual homs - only presentation of category theory

Suppose that you have an abstract for a scientific paper: the search for sharp features in the gamma - ray spectrum is a promising approach to identify a signal from dark matter annihilations over the astrophysical backgrounds . in this paper we investigate the generation of gamma - ray lines and internal bremsstrahlung signals in a toy model where the dark matter particle is a real scalar that couples to a lepton and an exotic fermion via a yukawa coupling . we show that the fermi - lat and h.e.s.s . searches for line - like spectral features severely constrain regions of the parameter space where the scalar dark matter is thermally produced . finally , we also discuss the complementarity of the searches for sharp spectral features with other indirect dark matter searches , as well as with direct and collider searches . . And you have already written the first three sentences of the full article: multiple astrophysical and cosmological observations have demonstrated that a significant fraction of the matter content of the universe is in the form of new particles not included in the standard model , but belonging to the so - called dark sector ( see @xcite for reviews ) . the dark matter ( dm ) particles were presumably produced during the very early stages of the universe and must have a relic abundance today @xmath0 @xcite . among the various production mechanisms proposed , the freeze - out mechanism stands among the most appealing and predictive ones . in this framework , the dark matter particles were in thermal equilibrium with the standard model particles at very early times , but went out of equilibrium when the temperature reached a value @xmath1 .. Please generate the next two sentences of the article

below this temperature , the expansion rate became larger than the annihilation rate and therefore the number density of dark matter particles per comoving volume remained practically constant until today , the value being inversely proportional to their annihilation cross section into standard model particles . the annihilations that lead to the freeze - out of dark matter particles in the early universe presumably continue today , at a much smaller rate , in regions with high dark matter density , such as in galactic centers .

Suppose that you have an abstract for a scientific paper: much progress in the theory of positron scattering on atoms has been made in the ten years since the review of @xcite . we review this progress for few - electron targets with a particular emphasis on the two - centre convergent close - coupling and other theories which explicitly treat positronium ( ps ) formation . while substantial progress has been made for ps formation in positron scattering on few - electron targets , considerable theoretical development is still required for multielectron atomic and molecular targets . . And you have already written the first three sentences of the full article: there have been many reviews of positron physics over the years @xcite . more recently @xcite and @xcite considered the subject with an emphasis on experimental measurements involving noble gas targets . the related topic of antihydrogen formation has also been thoroughly reviewed @xcite .. Please generate the next two sentences of the article

resonances and the closely related bound states of positrons with atoms and molecules has also been extensively discussed @xcite . this work concentrates on the progress in application of theoretical methods to scattering processes in a quantum few - body system involving positrons as projectiles and multi - electron atomic targets with explicit treatment of positronium formation .

Suppose that you have an abstract for a scientific paper: techniques for the construction of dynamical galaxy models should be considered essential infrastructure that should be put in place before gaia flies . three possible modelling techniques are discussed . although one of these seems to have significantly more potential than the other two , at this stage work should be done on all three . a major effort is needed to decide how to make a model consistent with a catalogue such as that which gaia will produce . given the complexity of the problem , it is argued that a hierarchy of models should be constructed , of ever increasing complexity and quality of fit to the data . the potential that resonances and tidal streams have to indicate how a model should be refined is briefly discussed . . And you have already written the first three sentences of the full article: a central goal of the gaia mission is to teach us how the galaxy functions and how it was assembled . we can only claim to understand the structure of the galaxy when we have a dynamical model galaxy that reproduces the data . therefore the construction of a satisfactory dynamical model is in a sense a primary goal of the gaia mission , for this model will encapsulate the understanding of galactic structure that we have gleaned from gaia .. Please generate the next two sentences of the article

preliminary working models that are precursors of the final model will also be essential tools as we endeavour to make astrophysical sense of the gaia catalogue . consequently , before launch we need to develop a model - building capability , and with it produce dynamical models that reflect fairly fully our current state of knowledge .

Suppose that you have an abstract for a scientific paper: we analyze the absorption and emission - line profiles produced by a set of simple , cool gas wind models motivated by galactic - scale outflow observations . we implement monte carlo radiative transfer techniques that track the propagation of scattered and fluorescent photons to generate 1d spectra and 2d spectral images . we focus on the @xmath0 doublet and uv1 multiplet at @xmath1 , but the results are applicable to other transitions that trace outflows ( e.g. , , ) . by design , the resonance transitions show blue - shifted absorption but one also predicts strong resonance and fine - structure line - emission at roughly the systemic velocity . this line - emission ` fills - in ' the absorption reducing the equivalent width by up to @xmath2 , shift the absorption - lin centroid by tens of , and reduce the effective opacity near systemic . analysis of cool gas outflows that ignores this line - emission may incorrectly infer that the gas is partially covered , measure a significantly lower peak optical depth , and/or conclude that gas at systemic velocity is absent ( e.g. an interstellar or slowly infalling component ) . because the lines are connected by optically - thin transitions to fine - structure levels , their profiles more closely reproduce the intrinsic opacity of the wind . together these results naturally explain the absorption and emission - line characteristics observed for star - forming galaxies at @xmath3 . we also study a scenario promoted to describe the outflows of @xmath4 lyman break galaxies and find prfiles inconsistent with the observations due to scattered photon emission . although line - emission complicates the analysis of absorption - line profiles , the surface brightness profiles offer a unique means of assessing the morphology and size of galactic - scale winds . furthermore , the kinematics and line - ratios offer powerful diagnostics of outflows , motivating deep , spatially - extended spectroscopic observations . # 1 10^#1 5 ly-5 6 ly-6 7 ly-7 @xmath5 . And you have already written the first three sentences of the full article: nearly all gaseous objects that shine are also observed to generate gaseous flows . this includes the jets of protostars , the stellar winds of massive o and b stars , the gentle solar wind of our sun , the associated absorption of bright quasars , and the spectacular jets of radio - loud agn . these gaseous outflows regulate the metal and dust content and distribution within the objects and their surroundings , moderate the accretion of new material , and inject energy and momentum into gas on large scales . developing a comprehensive model for these flows is critical to understanding the evolution of the source and its impact on the surrounding environment .. Please generate the next two sentences of the article

starburst galaxies , whose luminosity is dominated by regions and massive stars , are also observed to drive gaseous outflows . these flows are generally expected ( and sometimes observed ) to have multiple phases , for example a hot and diffuse phase traced by x - ray emission together with a cool , denser phase traced by h@xmath6 emission ( e.g. * ? ? ?

Suppose that you have an abstract for a scientific paper: we analyse the kinematics of the entire spectroscopic sample of 99 recently discovered high proper - motion white dwarfs by oppenheimer et al . using a maximum - likelihood analysis , and discuss the claim that the high - velocity white dwarfs are members of a halo population with a local density at least ten times greater than traditionally assumed . we argue that the observations , as reported , are consistent with the presence of an almost undetected thin disc plus a thick disc , with densities as conventionally assumed . in addition , there is a kinematically distinct , flattened , halo population at the more than 99% confidence level . surprisingly , the thick disc and halo populations are indistinguishable in terms of luminosity , color and apparent age ( 110 gyr ) . adopting a bimodal , schwarzschild model for the local velocity ellipsoid , with the ratios @xmath0:@xmath1:@xmath2=1:2/3:1/2 , we infer radial velocity dispersions of @xmath3=62@xmath4 kms@xmath5 and 150@xmath6 kms@xmath5 ( 90% c.l . ) for the local thick disc and halo populations , respectively . the thick disc result agrees with the empirical relation between asymmetric drift and radial velocity dispersion , inferred from local stellar populations . the local thick - disc plus halo density of white dwarfs is @xmath7=@xmath8@xmath9 pc@xmath10 ( 90% c.l . ) , of which @xmath11=1.1@xmath12@xmath13@xmath14 pc@xmath10 ( 90% c.l . ) belongs to the halo , a density about five times higher than previously thought . adopting a mean white - dwarf mass of 0.6 m@xmath15 , the latter amounts to 0.8@xmath16@xmath1310@xmath17 ( 90% c.l . ) of the nominal local halo density . assuming a simple spherical logarithmic potential for the galaxy , we infer from our most - likely model an oblate halo white - dwarf density profile with @xmath18 and @xmath19 . the halo white dwarfs contributes @xmath20 m@xmath15 , i.e. a mass fraction of @xmath210.004 , to the total mass inside 50 kpc ( @xmath22 ) . the halo white dwarf population.... And you have already written the first three sentences of the full article: as the most common stellar remnants , white dwarfs ( wd ) provide an invaluable tracer of the early evolution of the galaxy . their current density and distribution reflects the disposition of their progenitor main sequence stars and their colors indicate their ages , which are consistent with many of them having been formed when the galaxy was quite young ( e.g. wood 1992 ) . until recently , it has been assumed that halo wds contribute a negligible fraction of the total mass of the galaxy ( e.g. gould , flynn & bahcall 1998 ) . this view is supported by the constraint that the formation of @xmath210.6m@xmath15 wds is accompanied by the release of several solar masses of gas , heavily enriched in cno elements ( e.g. charlot & silk 1995 ; gibson & mould 1997 ; canal , isern & ruiz - lapuente 1997 ) . yet. Please generate the next two sentences of the article

local stars and interstellar gas , which only comprise @xmath25% of the total galaxy mass , contain only 23 percent of these elements by mass . based on these metalicity arguments , most recently fields , freese & graff ( 2000 ) have argued that @xmath26@xmath27@xmath28 from c and n element abundances , adopting h@xmath29=70kms@xmath5mpc@xmath5 .

Suppose that you have an abstract for a scientific paper: a 90 ksec _ chandra _ hetg observation of the young stellar cluster ngc 6193 in the southern ara ob1 association detected 43 x - ray sources in a 2@xmath0 @xmath1 2@xmath0 core region centered on the massive o stars hd 150135 ( o6.5v ) and hd 150136 ( o3 @xmath2 o6v ) . the cluster is dominated by exceptionally bright x - ray emission from the two o stars , which are separated by only 10@xmath3 . the x - ray luminosity of hd 150136 is log l@xmath4 = 33.39 ( ergs s@xmath5 ) , making it one of the most luminous o - star x - ray sources known . all of the fainter x - ray sources in the core region have near - ir counterparts , but existing jhk photometry provides little evidence for near - ir excesses . these core sources have typical mean photon energies @xmath6e@xmath7 @xmath8 2 kev and about one - third are variable . it is likely that some are young low - mass stars in the cluster , but cluster membership remains to be determined . grating spectra show that the x - ray properties of hd 150135 and hd 150136 are similar , but not identical . both have moderately broadened unshifted emission lines and their emission is dominated by cool plasma at kt @xmath8 0.3 kev , pointing to a wind - shock origin . however , the emission of hd 150136 is slightly hotter and four times more luminous than its optical twin hd 150135 . we discuss the possibility that a radiative colliding wind shock contributes to the prodigious x - ray output of the short - period ( 2.66 d ) spectroscopic binary hd 150136 . a suprising result is that the x - ray emission of hd 150136 is slowly variable on a timescale of @xmath91 day . the origin of the variability is not yet known but the observed behavior suggests that it is an occultation effect . [ firstpage ] open clusters and associations : individual ( ngc 6193 , ara ob1 ) stars : formation stars : early - type stars : individual ( hd 150135 , hd 150136 ) x - rays : stars . . And you have already written the first three sentences of the full article: the southern ara ob1 association shows evidence of recent star formation that may have been triggered by a supernova event ( herbst & havlen 1977 , hereafter hh77 ; arnal et al . the remarkable young stellar cluster ngc 6193 lies near the center of ara ob1 and was first studied optically by whiteoak ( 1963 ) . a more comprehensive optical study was undertaken by hh77 who determined the foreground reddening and derived a distance of 1.32 @xmath10 0.12 kpc .. Please generate the next two sentences of the article

they identified the higher mass o , b , and a star cluster members , but lower mass members have not yet been isolated . the cluster is undoubtedly young with age estimates in the range @xmath111.5 - 3.1 myr ( moffat & vogt 1973 , hh77 , vzquez & feinstein 1992 ) .

Suppose that you have an abstract for a scientific paper: we present a sample of 46 galaxy nuclei from 12 nearby ( @xmath0 ) hickson compact groups ( hcgs ) with a complete suite of 124 2mass+_spitzer _ nuclear photometry . for all objects in the sample , blue emission from stellar photospheres dominates in the near - infrared through the 3.6 irac band . twenty - five of 46 ( 54% ) galaxy nuclei show red , mid - infrared continua characteristic of hot dust powered by ongoing star formation and/or accretion onto a central black hole . we introduce @xmath1 , the spectral index of a power - law fit to the 4.58.0 irac data , and demonstrate that it cleanly separates the mid - infrared active and non - active hcg nuclei . this parameter is more powerful for identifying low to moderate - luminosity mid - infrared activity than other measures which include data at rest - frame @xmath2 that may be dominated by stellar photospheric emission . while the hcg galaxies clearly have a bimodal distribution in this parameter space , a comparison sample from the _ spitzer _ nearby galaxy survey ( sings ) matched in @xmath3-band total galaxy luminosity is continuously distributed . a second diagnostic , the fraction of 24 emission in excess of that expected from quiescent galaxies , @xmath4 , reveals an additional three nuclei to be active at 24 . comparing these two mid - infrared diagnostics of nuclear activity to optical spectroscopic identifications from the literature reveals some discrepancies , and we discuss the challenges of distinguishing the source of ionizing radiation in these and other lower luminosity systems . we find a significant correlation between the fraction of mid - infrared active galaxies and the total mass in a group , and investigate possible interpretations of these results in light of galaxy evolution in the highly interactive system of a compact group environment . . And you have already written the first three sentences of the full article: the first galaxies and their environments differed substantially from those locally , often involving multiple interactions as seen in the _ hst _ ultra deep field ( e.g. , * ? ? ? compared to all other nearby environments , present - day compact galaxy groups most closely reproduce the interaction environment of the early universe ( @xmath5 ) when galaxies assembled through hierarchical formation ( e.g. , * ? ? ? * ) , and galaxy groups combined to form proto - clusters ( in dense regions ; e.g. , rudick+06 ) or massive ellipticals ( in the field ; white ) . because of their high space densities ( with comparable surface densities to the centers of rich galaxy clusters ; e.g. , rubin+91 ) and low velocity dispersions ( @xmath6 ) , compact groups of galaxies are ideal environments for studying the mechanisms of interaction - induced star formation and nuclear activity . from optical spectroscopic surveys , hickson compact groups ( hcgs ) are known to host a population of galaxies with emission - line nuclear spectra characteristic of star - formation and/or active galactic nuclei ( agns ) .. Please generate the next two sentences of the article

based on the optical spectroscopic survey of @xcite , the agn fraction in hcgs is found to be @xmath7 , perhaps consistent with the @xmath8 nuclear activity level found for nearby @xmath9 galaxies ( with greater detection sensitivity ; hoetal97a ) and significantly higher than the @xmath10 agn fraction identified optically in cluster galaxies ( with @xmath11 ; dressler85 ) . further , hcg agns ( including low - luminosity agns , hereafter llagns ; hcgs host no known seyfert 1-luminosity agns ) are preferentially found in optically luminous , early - type galaxies with little or no ongoing star formation in the cores of evolved groups .

Suppose that you have an abstract for a scientific paper: i summarize some results from the recent co survey of late - type , low surface brightness ( lsb ) spiral galaxies by matthews et al . ( 2005 ) . we have now detected co emission from six late - type , lsb spirals , demonstrating that despite their typical low metallicities and low mean gas surface densities , some lsb galaxies contain a molecular medium that is traced by co. we find that the co - detected lsb spirals adhere to the same @xmath0-fir correlation as brighter galaxies . we also find a significant drop - off in the detectability of co among low - to - intermediate surface brightness galaxies with @xmath190 km s@xmath2 , pointing toward fundamental changes in the physical conditions of the ism with decreasing disk mass . . And you have already written the first three sentences of the full article: low surface brightness ( lsb ) spiral galaxies are defined as having central disk surface brightnesses @xmath3 23 mag arcsec@xmath4 , indicating low stellar surface densities . however , despite their faint optical appearances , the majority of lsb spirals show evidence for ongoing star formation , including blue colors , h@xmath5 emission and/or resolved populations of young stars ( e.g. , schombert et al . 1992 ; gallagher & matthews 2002 ) . signatures of star formation are frequently coupled with large atomic gas fractions ( @xmath61 ) , underscoring that lsb spirals are not the faded remnants of brighter galaxies . in a number of cases ,. Please generate the next two sentences of the article

evidence is also seen for stellar populations spanning a wide range of ages ( e.g. , van den hoek et al . 2000 ) , implying that lsb spirals have been forming stars for a significant fraction of a hubble time but with low efficiency . lingering questions regarding the evolutionary history of lsb spirals are _ why _ their star formation has remained suppressed , and what physical processes regulate the type of low - level star formation that is observed in these systems . given that lsb spirals comprise a significant fraction ( @xmath750% ) of the local disk galaxy population ( e.g. , minchin et al .

Suppose that you have an abstract for a scientific paper: the ising spin - glasses are investigated on three dual pairs of hierarchical lattices , using exact renormalization - group transformation of the quenched bond probability distribution . the goal is to investigate a recent conjecture which relates , on such pairs of dual lattices , the locations of the multicritical points , which occur on the nishimori symmetry line . towards this end we precisely determine the global phase diagrams for these six hierarchical spin - glasses , using up to @xmath0 probability bins to represent the quenched distribution subjected to an exact renormalization - group transformation . we find in all three cases that the conjecture is realized to a very good approximation , even when the mutually dual models belong to different spatial dimensionalities @xmath1 and have different phase diagram topologies at the multicritical points of the conjecture and even though the contributions to the conjecture from each lattice of the dual pair are strongly asymmetric . in all six phase diagrams , we find reentrance near the multicritical point . in the models with @xmath2 or 1.5 , the spin - glass phase does not occur and the phase boundary between the ferromagnetic and paramagnetic phases is second order with a strong violation of universality . pacs numbers : 75.10.nr , 64.60.kw , 05.45.df , 05.10.cc . And you have already written the first three sentences of the full article: the phase diagram structure of spin - glasses remains an open field of inquiry , since most approaches to the problem rely on approximations . any exact analytical result in this area is thus very valuable , both for the direct information it provides and as a test for approximation methods . over the last few years striking progress has been made combining the replica method , duality , and symmetry arguments @xcite , an approach which has yielded the exact locations of the multicritical points in the ising and potts spin - glasses on the square lattice and in the four - dimensional random - plaquette gauge model .. Please generate the next two sentences of the article

the most recent result in this series @xcite is a general conjecture relating the multicritical point locations of any spin - glasses on a pair of mutually dual lattices . in support of the conjecture , estimates based on monte carlo simulations were given for ising spin - glasses , in @xmath2 , on the dual pairs of triangular and hexagonal lattices and , in @xmath3 , on the dual pairs of bilinear and lattice - gauge interactions on the cubic lattice . in both cases , within the numerical limitations , the conjecture is approximately satisfied .

Suppose that you have an abstract for a scientific paper: we present the current results of a survey for oh megamasers ( ohms ) underway at the arecibo observatory . the survey is 2/3 complete and has produced a high ohm detection rate ( 1 in 6 ) from a redshift - selected sample of _ iras _ galaxies . the survey will relate the ohm luminosity function to the galaxy merger rate , allowing subsequent blind ohm surveys to measure the galaxy merger rate as a function of cosmic time . the survey has also made the first detection of strong variability in ohms . variability will provide a powerful tool for understanding the small - scale physical settings and mechanisms of ohms . . And you have already written the first three sentences of the full article: the arecibo oh megamaser ( ohm ) survey selects candidates from the pscz redshift catalog ( saunders et al . 2000 ) with the criteria : ( 1 ) @xmath0 jy , ( 2 ) @xmath1 , and ( 3 ) @xmath2 ( darling & giovanelli 2000 ) . with a detection rate of 1 ohm in 6 candidates , the complete survey will double the sample of ohms to roughly 100 objects .. Please generate the next two sentences of the article

the survey has identified 35 new ohms in luminous infrared galaxies to add to the sample of 55 found in the literature . there is a strong bias for the most fir - luminous galaxies to host ohms , and a weak fir color dependence ( see figure 1 ) .

Suppose that you have an abstract for a scientific paper: in this paper , we study the dynamics of epidemic processes taking place in adaptive networks of arbitrary topology . we focus our study on the adaptive susceptible - infected - susceptible ( asis ) model , where healthy individuals are allowed to temporarily cut edges connecting them to infected nodes in order to prevent the spread of the infection . in this paper , we derive a closed - form expression for a lower bound on the epidemic threshold of the asis model in arbitrary networks with heterogeneous node and edge dynamics . for networks with homogeneous node and edge dynamics , we show that the resulting lower bound is proportional to the epidemic threshold of the standard sis model over static networks , with a proportionality constant that depends on the adaptation rates . furthermore , based on our results , we propose an efficient algorithm to optimally tune the adaptation rates in order to eradicate epidemic outbreaks in arbitrary networks . we confirm the tightness of the proposed lower bounds with several numerical simulations and compare our optimal adaptation rates with popular centrality measures . . And you have already written the first three sentences of the full article: the analysis of dynamic processes taking place in complex networks is a major research area with a wide range of applications in social , biological , and technological systems @xcite . the spread of information in online social networks , the evolution of an epidemic outbreak in human contact networks , and the dynamics of cascading failures in the electrical grid are relevant examples of these processes . while major advances have been made in this field , most modeling and analysis techniques are specifically tailored to study dynamic processes taking place in static networks .. Please generate the next two sentences of the article

however , empirical observations in social @xcite , biological @xcite , and financial networks @xcite illustrate how real - world networks are constantly evolving over time @xcite . unfortunately , the effects of temporal structural variations in the dynamics of networked systems remain poorly understood . in the context of temporal networks , we are specially interested in the interplay between the dynamics on networks ( i.e. , the dynamics of processes taking place in the network ) and the dynamics of networks ( i.e. , the temporal evolution of the network structure ) . although the dynamics on and of networks are usually studied separately , there are many cases in which the evolution of the network structure is heavily influenced by the dynamics of processes taking place in the network .

Suppose that you have an abstract for a scientific paper: the central pointlike x - ray source of the cas a supernova remnant was discovered in the first light observation and found later in the archival and images . the analysis of these data does not show statistically significant variability of the source . because of the small number of photons detected , different spectral models can fit the observed spectrum . the power - law fit yields the photon index @xmath04.1 , and luminosity @xmath1@xmath2@xmath3 erg s@xmath4 , for @xmath5 kpc . the power - law index is higher , and the luminosity lower , than those observed from very young pulsars . one can fit the spectrum equally well with a blackbody model with @xmath68 mk , @xmath7@xmath8 km , @xmath9@xmath10 erg s@xmath4 . the inferred radii are too small , and the temperatures too high , for the radiation could be interpreted as emitted from the whole surface of a uniformly heated neutron star . fits with the neutron star atmosphere models increase the radius and reduce the temperature , but these parameters are still substantially different from those expected for a young neutron star . one can not exclude , however , that the observed emission originates from hot spots on a cooler neutron star surface . because of strong interstellar absorption , the possible low - temperature component gives a small contribution to the observed spectrum ; an upper limit on the ( gravitationally redshifted ) surface temperature is @xmath112.3 mk , depending on chemical composition of the surface and star s radius . amongst several possible interpretations , we favor a model of a strongly magnetized neutron star with magnetically confined hydrogen or helium polar caps ( @xmath12 mk , @xmath13 km ) on a cooler iron surface ( @xmath14 mk ) . such temperatures are consistent with the standard models of neutron star cooling . alternatively , the observed radiation may be interpreted as emitted by a compact object ( more likely , a black hole ) accreting from a fossil disk or from a late - type dwarf in.... And you have already written the first three sentences of the full article: cassiopeia a is the brightest shell - type galactic supernova remnant ( snr ) in x - rays and radio , and the youngest snr observed in our galaxy . the radius of the approximately spherical shell is @xmath15 , which corresponds to @xmath16 pc for the distance @xmath17 kpc ( reed et al . the supernova which gave rise to cas a was probably first observed in 1680 ( ashworth 1980 ) .. Please generate the next two sentences of the article

it is thought to be a type ii supernova caused by explosion of a very massive wolf - rayet star ( fesen , becker & blair 1987 ) . optical observations of cas a show numerous oxygen - rich fast - moving knots ( fmk ) , with velocities of about 5000 km s@xmath4 , and slow - moving quasi - stationary flocculi , with typical velocities of about 200 km s@xmath4 , which emit h@xmath18 and strong lines of nitrogen .

Suppose that you have an abstract for a scientific paper: stars form in dense cores of molecular clouds that are observed to be significantly magnetized . in the simplest case of a laminar ( non - turbulent ) core with the magnetic field aligned with the rotation axis , both analytic considerations and numerical simulations have shown that the formation of a large , @xmath0-scale , rotationally supported protostellar disk is suppressed by magnetic braking in the ideal mhd limit for a realistic level of core magnetization . this theoretical difficulty in forming protostellar disks is termed `` magnetic braking catastrophe . '' a possible resolution to this problem , proposed by @xcite and @xcite , is that misalignment between the magnetic field and rotation axis may weaken the magnetic braking enough to enable disk formation . we evaluate this possibility quantitatively through numerical simulations . we confirm the basic result of @xcite that the misalignment is indeed conducive to disk formation . in relatively weakly magnetized cores with dimensionless mass - to - flux ratio @xmath1 , it enabled the formation of rotationally supported disks that would otherwise be suppressed if the magnetic field and rotation axis are aligned . for more strongly magnetized cores , disk formation remains suppressed , however , even for the maximum tilt angle of @xmath2 . if dense cores are as strongly magnetized as indicated by oh zeeman observations ( with a mean dimensionless mass - to - flux ratio @xmath3 ) , it would be difficult for the misalignment alone to enable disk formation in the majority of them . we conclude that , while beneficial to disk formation , especially for the relatively weak field case , the misalignment does not completely solve the problem of catastrophic magnetic braking in general . . And you have already written the first three sentences of the full article: star and planet formation are connected through disks . disk formation , long thought to be a trivial consequence of angular momentum conservation during core collapse and star formation ( e.g. , bodenheimer1995 ) , turned out to be much more complicated than originally envisioned . the complication comes from magnetic fields , which are observed in dense , star - forming , cores of molecular clouds ( see crutcher2012 for a recent review ) .. Please generate the next two sentences of the article

the field can strongly affect the angular momentum evolution of core collapse and disk formation through magnetic braking . there have been a number of studies aiming at quantifying the effects of magnetic field on disk formation . in the ideal mhd limit

Suppose that you have an abstract for a scientific paper: recently much attention has been paid to the study of the robustness of interdependent and multiplex networks and , in particular , networks of networks . the robustness of interdependent networks can be evaluated by the size of a mutually connected component when a fraction of nodes have been removed from these networks . here we characterize the emergence of the mutually connected component in a network of networks in which every node of a network ( layer ) @xmath0 is connected with @xmath1 its randomly chosen replicas in some other networks and is interdependent of these nodes with probability @xmath2 . we find that when the superdegrees @xmath1 of different layers in the network of networks are distributed heterogeneously , multiple percolation phase transition can occur . we show that , depending on the value of @xmath2 , these transition are continuous or discontinuous . . And you have already written the first three sentences of the full article: the complexity of a large variety of systems , from infrastructures to the cell , is rooted in a network of interactions between their constituents @xcite . quantifying the robustness of complex networks is one of the main challenges of network of networks with implications in fields as different as biology or policy making and risk assessment . in the last fifteen years it has been shown @xcite that the structure of a single network is strictly related to its robustness .. Please generate the next two sentences of the article

but only recently @xcite , attention has been drawn toward a previously neglected aspects of complex systems , namely the interactions between several complex networks . rarely single networks are isolated , while it is usually the case that several networks are interacting and interdependent on each other .

Suppose that you have an abstract for a scientific paper: the recent discovery of a gravitational wave from the merging of two black holes of about 30 solar masses each challenges our incomplete understanding of massive stars and their evolution . critical ingredients comprise mass - loss , rotation , magnetic fields , internal mixing , and mass transfer in close binary systems . the imperfect knowledge of these factors implies large uncertainties for models of stellar populations and their feedback . in this contribution we summarize our empirical studies of wolf - rayet populations at different metallicities by means of modern non - lte stellar atmosphere models , and confront these results with the predictions of stellar evolution models . at the metallicity of our galaxy , stellar winds are probably too strong to leave remnant masses as high as @xmath030m@xmath1 , but given the still poor agreement between evolutionary tracks and observation even this conclusion is debatable . at the low metallicity of the small magellanic cloud , all wn stars which are ( at least now ) single are consistent with evolving quasi - homogeneously . o and b - type stars , in contrast , seem to comply with standard evolutionary models without strong internal mixing . close binaries which avoided early merging could evolve quasi - homogeneously and lead to close compact remnants of relatively high masses that merge within a hubble time . . And you have already written the first three sentences of the full article: at the 14th of september 2015 , the advanced ligo detectors registered for the first time a gravitational wave ( * ? ? ? * ( abbott 2016 ) ) . according to the analysis of the waveform , this wave testified the event of two merging black holes ( bhs ) of @xmath2 and @xmath3 at a distance of about 400mpc .. Please generate the next two sentences of the article

the immediate conclusion , and even the prediction prior to the measurement , was that such heavy bhs can only form by stellar evolution at low metallicity , where the mass - loss due to stellar winds is low and hence the stellar remnants can be more massive ( * ? ? ? * ( belczynski 2016 ) ) . still heavily debated is whether such bhs form separately in dense clusters and then combine into a close pair by dynamical interactions , or whether they evolve as close binaries all the time .

Suppose that you have an abstract for a scientific paper: we report spatially resolved , time - dependent , magnetization reversal measurements of an fe@xmath0 single molecular magnet using a microscopic hall bar array . we found that under some conditions the molecules reverse their spin direction at a resonance field in the form of an avalanche . the avalanche front velocity is of the order of @xmath1 m / sec and is sensitive to field gradients and sweep rates . we also measured the propagation velocity of a heat pulse and found that it is much slower than the avalanche velocity . we therefore conclude that in fe@xmath0 , the avalanche front propagates without thermal assistance . single molecular magnets ( smm ) are an excellent model system for the study of macroscopic quantum phenomena and their interplay with the environment . in recent years , the focus of these studies shifted from single molecule to collective effects . while there are two famous smm that show quantum behavior , namely , fe@xmath0 and mn@xmath2 , most of the work on collective effects has been focused on mn@xmath2 . indeed , in mn@xmath2 intriguing effects were found , such as deflagration @xcite , quantum assisted deflagration @xcite , and detonation @xcite . in all these cases , a spin reversal front propagates through the sample as an avalanche . although showing some signs of quantum behavior hernandez2005 , these processes are based on over - the - barrier magnetization reversal . here , we focus on the spin avalanche phenomena in fe@xmath0 , where pure quantum effects exist at dilution refrigerator ( dr ) temperatures . we measure the avalanche velocity @xmath3 for various sweep rates and applied field gradients . we also determine the thermal diffusivity . we find that @xmath4 is much faster than the velocity at which heat or matching field propagates through the sample . moreover , @xmath3 is affected by field gradients . therefore , the avalanche in fe@xmath0 is a quantum effect sometimes called cold deflagration @xcite . fe@xmath0 provides the first.... And you have already written the first three sentences of the full article: the hall sensor array resides in the center of a printed circuit board ( pcb ) . there is a hole in the pcb and the hall sensor is glued directly on a copper plate cold finger , which extends from the dr mixing chamber . gold wire bonding connects the sensors and the leads on the pcb .. Please generate the next two sentences of the article

all wires are thermally connected to the mc . typical sample dimensions are 3 @xmath18 2 @xmath71 1 mm@xmath31 .

Suppose that you have an abstract for a scientific paper: critical behavior of the infrared reflectivity of rusr@xmath0gdcu@xmath0o@xmath1 ceramics is observed near the superconducting @xmath2 = 45 k and magnetic @xmath3 = 133 k transition temperatures . the optical conductivity reveals the typical features of the @xmath4-axis optical conductivity of strongly underdoped multilayer superconducting cuprates . the transformation of the cu - o bending mode at 288 @xmath5 to a broad absorption peak at the temperatures between @xmath6 = 90 k and @xmath2 is clearly observed , and is accompanied by the suppression of spectral weight at low frequencies . the correlated shifts to lower frequencies of the ru - related phonon mode at 190 @xmath5 and the mid - ir band at 4800 @xmath5 on decreasing temperature below @xmath3 are observed . it provides experimental evidence in favor of strong electron - phonon coupling of the charge carriers in the ru - o layers which critically depends on the ru core spin alignment . the underdoped character of the superconductor is explained by strong hole depletion of the cuo@xmath0 planes caused by the charge carrier self - trapping at the ru moments . . And you have already written the first three sentences of the full article: the layered ruthenate - cuprate compound rusr@xmath0gdcu@xmath0o@xmath1 ( ru-1212 ) is a subject of intense interest as a unique model system to study the interplay between superconductivity and ferromagnetism . a ferromagnetic ( fm ) moment of the ru - o layers coexists with superconductivity originating from the cu - o bilayers over a broad temperature range.@xcite long - range magnetic - order in ru-1212 is established at t@xmath7 = 133 k. recent neutron - diffraction and magnetization studies@xcite display that in zero external magnetic field the magnetic order of the ru moments is predominately antiferromagnetic along the @xmath4-axis with spin canting in the @xmath8-plane . the net in - plane magnetic moment is most likely due to the rotations of the ruo@xmath9 octahedra .. Please generate the next two sentences of the article

it is suggested that there is a field - induced spin reorientation , and that already at moderate fields the order becomes predominately ferromagnetic . at the same time @xmath10 transport and heat - capacity measurements show that ru-1212 behaves like a typical underdoped cuprate superconductor with the onset of superconductivity at @xmath2 = 45 k and clearly exhibits a number of features arising from the presence of a normal state pseudogap .

Suppose that you have an abstract for a scientific paper: some tails of ram - pressure stripped galaxies are detected in h@xmath0 , some in h@xmath1 , and some in x - ray ( but never all three so far ) . we use numerical simulations to probe the conditions for the production of x - ray bright tails , demonstrating that the primary requirement is a high pressure intracluster medium ( icm ) . this is because the stripped tail is mostly in pressure equilibrium with the icm , but mixing leaves it with densities and temperatures intermediate between the cold gas in the disk and the hot icm . given a high enough icm pressure , this mixed gas lies in the x - ray bright region of the phase diagram . we compare the simulations to observations of the ram pressure stripped tail of eso 137 - 001 , showing excellent agreement in the total measured x - ray and h@xmath1 emission and non - flaring morphology of the tail , and consistent h@xmath0 measurements . using these comparisons we constrain the level of mixing and efficiency of heat conduction in the intracluster medium ( icm ) . . And you have already written the first three sentences of the full article: ram pressure ( and related processes ) by the intracluster medium ( icm ) can remove a galaxy s gas ( gunn & gott 1972 ) . this process has been observed in various stages ; for example , vollmer ( 2009 ) separates virgo galaxies into pre - peak , peak , and post - peak ram pressure groups . the amount of time that a galaxy has been stripped can be estimated using the length of the observable tail and the velocity of the galaxy ( e.g. oosterloo & van gorkom 2005 ; sun et al .. Please generate the next two sentences of the article

this calculation is uncertain due to difficulties in determining the three dimensional galaxy velocity . another assumption implicit in this calculation is that the observed tail provides the true length of the stripped gas .

Suppose that you have an abstract for a scientific paper: using spectral data from non - strange and strange hadronic @xmath0 decays , flavor - breaking chiral sum rules involving the flavor @xmath1 and @xmath2 current - current two - point functions are constructed and used to determine the @xmath3 nnlo low - energy constant combinations @xmath4 , @xmath5 and @xmath6 . the first of these determinations updates the results of an earlier analysis by drr and kambor , while the latter two are new . the error on the @xmath5 is particularly small . comparisons are made to model estimates for these quantities . the role of the third combination in significantly improving the determination of the nlo low - energy constant @xmath7 from nnlo analyses of the flavor @xmath1 v - a correlator is also highlighted . . And you have already written the first three sentences of the full article: chiral perturbation theory ( chpt ) provides a means of implementing , in the most general way , the constraints on low - energy processes of the symmetries of qcd @xcite . the effects of resonances , and other heavy degrees of freedom , are encoded in the low - energy constants ( lecs ) which appear in the resulting effective chiral lagrangian multiplying those operators allowed by these constraints . in the even - intrinsic - parity sector , at next - to - leading order ( nlo ) in the chiral counting , the @xmath8 lagrangian involves @xmath9 in - principle - measurable lecs , the @xmath10 introduced in ref . the next - to - next - to - leading order ( nnlo ) form was first considered in ref .. Please generate the next two sentences of the article

@xcite , and a reduced minimal set of operators subsequently found in refs . the minimal nnlo @xmath3 form involves @xmath11 additional lecs , @xmath12 in contact and @xmath13 in non - contact terms . in what follows

Suppose that you have an abstract for a scientific paper: the relaxation times over which dissipative fluxes restore their steady state values have been evaluated for a pion gas using the 14-moment method . the effect of the medium has been implemented through a temperature dependent @xmath0 cross - section in the collision integral which is obtained by including one - loop self - energies in the propagators of the exchanged @xmath1 and @xmath2 mesons . to account for chemical freeze out in heavy ion collisions , a temperature dependent pion chemical potential has been introduced in the distribution function . the temperature dependence of the relaxation times for shear and bulk viscous flows as well as the heat flow is significantly affected . . And you have already written the first three sentences of the full article: characterizing the thermodynamic properties of matter composed of strongly interacting particles has been the premier objective of heavy ion collision experiments at the relativistic heavy ion collider ( rhic ) at brookhaven and the large hadron collider ( lhc ) at cern @xcite . relativistic hydrodynamics has played a very important role in analyzing the data from these collisions @xcite and providing a viable description of the collective dynamics of the produced matter . recently , the observation of a large elliptic flow(@xmath3 ) of hadrons in 200 agev au - au collisions at rhic could be explained quantitatively using a small but finite value of shear viscosity over entropy density ( @xmath4 ) @xcite .. Please generate the next two sentences of the article

however , a consistent formulation of relativistic dissipative fluid dynamics is far from trivial . the first order theories are seen to lead to instabilities due to acausal propagation of perturbations .

Suppose that you have an abstract for a scientific paper: we consider high energy electron scattering by hydrogen atoms in the presence of a laser field of moderate power and higher frequencies . if the field is a superposition of a linearly and a circularly polarized laser beam in a particular configuration , then we can show that circular dichroism in two photon transitions can be observed not only for the differential but also for the integrated cross sections , provided the laser - dressing of the atomic target is treated in second order perturbation theory and the coupling between hydrogenic bound and continuum states is involved . pacs numbers : 34.80.qb ; 34.50.rk ; 32.80.wr this is the revtex shell . . And you have already written the first three sentences of the full article: dichroism is a well known concept in classical optics where it denotes the property shown by certain materials of having absorption coefficients which depend on the state of polarization of the incident light @xcite . this concept has been further extended to the case of atomic or molecular interactions with a radiation field . in particular , the notion of circular dichroism in angular distribution ( cdad ) refers to the difference between the differential cross sections ( dcs ) of laser assisted signals for _ left _ ( @xmath0 ) and _ right _. Please generate the next two sentences of the article

( @xmath1 ) circularly polarized ( @xmath2 ) light @xcite . here we investigate the effect of the photon state of polarization , _ i.e. _ of its helicity , in laser - assisted high energy electron - hydrogen scattering .

Suppose that you have an abstract for a scientific paper: we have developed a new methodology and a time - domain software package for the estimation of the oscillation frequency and the phase noise spectrum of non - linear noisy microwave circuits based on the direct integration of the system of stochastic differential equations representing the circuit . our theoretical evaluations can be used in order to make detailed comparisons with the experimental measurements of phase noise spectra in selected oscillating circuits . . And you have already written the first three sentences of the full article: electronically tuned microwave oscillators are key components used in a wide variety of microwave communications systems @xcite . the phase of the output signal exhibits fluctuations in time about the steady state oscillations giving rise to phase noise a very important characteristic that influences the overall performance especially at higher microwave frequencies . in order to understand the oscillator phase behaviour , a statistical model for a non - linear oscillating circuit has to be developed and presently , no accurate theoretical model for phase noise characterization is available because of the particularly difficult nature of this problem . this is due to the hybrid nature of non - linear microwave oscillator circuits where distributed elements ( pertaining usually to the associated feeding or resonator circuits ) and non - linear elements ( pertaining usually to the amplifiying circuit ) have to be dealt with simultaneously @xcite .. Please generate the next two sentences of the article

the main aim of this report is to establish a theoretical framework for dealing with the noise sources and non- linearities present in these oscillators , introduce a new methodology to calculate the resonance frequency and evaluate the time responses ( waveforms ) for various voltages and currents in the circuit without or with the noise present . once this is established , the phase noise spectrum is determined and afterwards the validity range of the model is experimentally gauged with the use of different types of microwave oscillators @xcite .

Suppose that you have an abstract for a scientific paper: we consider two alternative tests to the higher criticism test of donoho and jin [ _ ann . statist . _ * 32 * ( 2004 ) 962994 ] for high - dimensional means under the sparsity of the nonzero means for sub - gaussian distributed data with unknown column - wise dependence . the two alternative test statistics are constructed by first thresholding @xmath0 and @xmath1 statistics based on the sample means , respectively , followed by maximizing over a range of thresholding levels to make the tests adaptive to the unknown signal strength and sparsity . the two alternative tests can attain the same detection boundary of the higher criticism test in [ _ ann . statist . _ * 32 * ( 2004 ) 962994 ] which was established for uncorrelated gaussian data . it is demonstrated that the maximal @xmath1-thresholding test is at least as powerful as the maximal @xmath0-thresholding test , and both the maximal @xmath1 and @xmath0-thresholding tests are at least as powerful as the higher criticism test . , . And you have already written the first three sentences of the full article: let @xmath2 be independent and identically distributed ( i.i.d . ) @xmath3-variate random vectors generated from the following model : @xmath4 where @xmath5 is a @xmath3-dimensional unknown vector of means , @xmath6 and @xmath7 are i.i.d . random vectors with zero mean and common covariance @xmath8 . for the @xmath9th sample , @xmath10 is a sequence of weakly stationary dependent random variables with zero mean and variances @xmath11 .. Please generate the next two sentences of the article

motivated by the high - dimensional applications arising in genetics , finance and other fields , the current paper focuses on testing high - dimensional hypotheses @xmath12 the specifications for the sparsity and faintness in the above @xmath13 are the following . there are @xmath14 nonzero @xmath15 s ( signals ) for a @xmath16 , which are sparse since the signal bearing dimensions constitute only a small fraction of the total @xmath3 dimensions . also under the @xmath13 ,

Suppose that you have an abstract for a scientific paper: we present numerical and analytical results for a special kind of one - dimensional probabilistic cellular automaton , the so called domany - kinzel automaton . it is shown that the phase boundary separating the active and the recently found chaotic phase exhibits reentrant behavior . furthermore exact results for the @xmath0=0-line are discussed . pacs numbers : 87.10.+e , 02.50.+s , 89.80.+h cellular automata have been an intensive research field in recent years @xcite due to their computational simplicity and the wide range of applications in various areas . even in one dimension a particular probabilistic variant ( domany - kinzel automaton ) of the originally deterministic cellular automata shows a rich phase diagram including directed percolation and other critical phenomena @xcite . only recently a new phase in this model has been explored numerically exhibiting chaotic behavior @xcite . this region of the diagram , up to a deterministic corner - point , is not accessible to exact treatments up to now . nevertheless sophisticated approximation - methods , which systematically go beyond mean - field theory , have been applied successfully @xcite . in the so called tree - aproximation @xcite one finds reentrant behavior in two directions , which is not fully understood yet . this phenomenon has never been observed in numerical simulations up to now @xcite . therefore one might ask , whether this reentrant behavior is a real feature of the model or just an artifact of the tree - approximation . this issue is the main topic of the present paper , where we try to clearify this point with an alternative approximation method ( the cluster - approximation ) as well as with large scale monte - carlo simulations ( up to @xmath1 sites ) . to state the final results already at this place : the cluster - approximation again yields reentrant behavior in two directions and the simulations show clear evidence for reentrance near the tricritical point . the model we consider is.... And you have already written the first three sentences of the full article: we thank g. kohring , d. stauffer and c. tsallis for interesting discussions . this work was performed within the sfb 341 kln aachen jlich supported by the dfg .. Please generate the next two sentences of the article

[ fig2 ] time - dependence of the activity for @xmath42 and various values of @xmath13 . the system size is @xmath72 . concerning the statistical error we observe that all runs using different random numbers yield curves that are indistinguishable on this scale .

Suppose that you have an abstract for a scientific paper: we present the first direct comparison between balmer line and panchromatic sed - based sfrs for @xmath0 galaxies . for this comparison we used 17 star - forming galaxies selected from the mosfire deep evolution field ( mosdef ) survey , with @xmath1 detections for h@xmath2 and at least two ir bands ( _ spitzer_/mips 24@xmath3 m and _ herschel_/pacs 100 and 160@xmath3 m , and in some cases _ herschel_/spire 250 , 350 , and 500@xmath3 m ) . the galaxies have total ir ( @xmath4 m ) luminosities of @xmath5 and star - formation rates ( sfrs ) of @xmath6 . we fit the uv - to - far - ir seds with flexible stellar population synthesis ( fsps ) models which include both stellar and dust emission and compare the inferred sfrs with the sfr(h@xmath2,h@xmath7 ) values corrected for dust attenuation using balmer decrements . the two sfrs agree with a scatter of 0.17 dex . our results imply that the balmer decrement accurately predicts the obscuration of the nebular lines and can be used to robustly calculate sfrs for star - forming galaxies at @xmath0 with sfrs up to @xmath8 . we also use our data to assess sfr indicators based on modeling the uv - to - mid - ir seds or by adding sfr(uv ) and sfr(ir ) , for which the latter is based on the mid - ir only or on the full ir sed . all these sfrs show a poorer agreement with sfr(h@xmath2,h@xmath7 ) and in some cases large systematic biases are observed . finally , we show that the sfr and dust attenuation derived from the uv - to - near - ir sed alone are unbiased when assuming a delayed exponentially declining star - formation history . . And you have already written the first three sentences of the full article: star - formation rates ( sfrs ) are among the most fundamental measurements for constraining the physics of galaxy formation and evolution . the past decade has seen a multitude of studies that trace sfrs out to high redshift ( * ? ? ? * and references therein ) , and examined their correlation with other galaxy properties , such as stellar masses ( e.g. , * ? ? ? * ; * ? ? ?. Please generate the next two sentences of the article

* ; * ? ? ? the _ spitzer space telescope _ and _ herschel space observatory _ opened a new window into measuring bolometric sfrs by allowing us to directly correct the widely - used sfrs(uv ) for dust - obscured star formation ( e.g. , * ? ? ? * ; * ? ? ? * ; * ? ? ? * ) . however , despite their common use , the uv+ir sfrs have several disadvantages : first , due to the limited spatial resolution and sensitivity of _ spitzer _ and _ herschel _ , most of the individual distant galaxies are not detectable in ir images , and second , the empirical templates used to convert the mid - ir ( restframe 8@xmath3 m ) fluxes to total ir luminosities result in systematic biases @xcite .

Suppose that you have an abstract for a scientific paper: we report the discovery of gas streaming motions along nuclear spiral arms towards the liner nucleus of the galaxy ngc6951 . the observations , obtained using the gmos integral field spectrograph on the gemini north telescope , yielded maps of the flux distributions and gas kinematics in the h@xmath0 , [ nii]@xmath16584 and [ sii]@xmath26717,31 emission lines of the inner 7@xmath315 of the galaxy . this region includes a circumnuclear star - forming ring with radius @xmath4500pc , a nuclear spiral inside the ring and the liner nucleus . the kinematics of the ionized gas is dominated by rotation , but subtraction of a kinematic model of a rotating exponential disk reveals deviations from circular rotation within the nuclear ring which can be attributed to ( 1 ) streaming motions along the nuclear spiral arms and ( 2 ) a bipolar outflow which seems to be associated to a nuclear jet . on the basis of the observed streaming velocities and geometry of the spiral arms we estimate a mass inflow rate of ionized gas of @xmath5m@xmath6yr@xmath7 , which is of the order of the accretion rate necessary to power the liner nucleus of ngc6951 . similar streaming motions towards the nucleus of another galaxy with liner nucleus ngc1097 have been reported by our group in a previous paper . taken together , these results support a scenario in which nuclear spirals are channels through which matter is transferred from galactic scales to the nuclear region to feed the supermassive black hole . . And you have already written the first three sentences of the full article: one long - standing problem in the study of nuclear activity in galaxies is to understand how mass is transferred from galactic scales down to nuclear scales to feed the supermassive black hole ( hereafter smbh ) inside . many theoretical studies and simulations ( shlosman et al . 1990 ; emsellem et al . 2003 ; knapen 2005 ; emsellem et al . 2006 ) have shown that non - axisymmetric potentials efficiently promote gas inflow towards the inner regions ( englmaier & shlosman 2004 ) .. Please generate the next two sentences of the article

recent observations have revealed that structures such as small - scale disks or nuclear bars and associated spiral arms are frequently observed in the inner kiloparsec of active galaxies ( erwin & sparke 1999 ; pogge & martini 2002 ; laine et al . 2003 ) . in a recent work ,

Suppose that you have an abstract for a scientific paper: we investigate the presence of off - diagonal long - range order in a harmonically confined two - dimensional bose gas . in the noninteracting case , an analytical calculation of the the finite - temperature one - particle density martix provides an exact description of the spatial correlations known to be associated with the existence of a bose - einstein condensate below the transition temperature @xmath0 . we treat the effects of repulsive interactions within the semiclassical hartree - fock - bogliubov approximation and find that even though the system remains in the same _ uncondensed phase _ for all @xmath1 , there appears to be a revival of off - diagonal long - range order for temperatures @xmath2 . we suggest that this reentrant order is related to a phase transition in the system which _ is not _ the bec state . . And you have already written the first three sentences of the full article: recent advances in the controlled fabrication and manipulation of ultra - low temperature trapped bose gases @xcite has finally made it possible to experimentally investigate the existence of off - diagonal long - range order ( odlro ) , i.e. , bose - einstein condensation ( bec ) , in dimensions lower than three . this remarkable experimental achievment has rekindled an interest in the classic theoretical problem concerning the existence of bec in two - dimensions ( 2d ) . although it is well known that finite - temperature bec can never occur in a homogeneous 2d bose gas @xcite , the ideal trapped bose gas can undergo bec below some critical temperature @xmath3 . in the case of a 2d isotropic harmonic trap with confining frequency @xmath4 ( unless stated otherwise , we always implicitly assume this confinement geometry ) , bagnato and kleppner have shown that @xmath5 @xcite , where @xmath6 ; shevchenko later extened this result to include more general power law potentials @xcite . in the thermodnyamic limit , viz .. Please generate the next two sentences of the article

, @xmath7 , @xmath8 , such that @xmath9 , bec is also known to theoretically occur with the critical temperature remaining unchanged . note that this is not the usual thermodynamic limit , which in 2d would demand that @xmath10 , resulting in no bec ( see also ref .

Suppose that you have an abstract for a scientific paper: recent theoretical works have shown that matter swapping between two parallel braneworlds could occur under the influence of magnetic vector potentials . in our visible world , galactic magnetism possibly produces a huge magnetic potential . as a consequence , this paper discusses the possibility to observe neutron disappearance into another braneworld in certain circumstances . the setup under consideration involves stored ultracold neutrons @xmath0 in a vessel @xmath0 which should exhibit a non - zero probability @xmath1 to disappear into an invisible brane at each wall collision . an upper limit of @xmath1 is assessed based on available experimental results . this value is then used to constrain the parameters of the theoretical model . possible improvements of the experiments are discussed , including enhanced stimulated swapping by artificial means . brane phenomenology , braneworlds , matter disappearance , ultracold neutrons . And you have already written the first three sentences of the full article: according to the braneworld hypothesis , our observable universe can be considered as a three - dimensional space sheet ( a @xmath2-brane ) embedded in a larger spacetime with @xmath3 dimensions ( the bulk ) @xcite . brane is a concept inherited from high energy physics and unification models . testing the existence of branes or extra dimensions is therefore becoming a fundamental challenge .. Please generate the next two sentences of the article

such evidences are expected to be obtained through high energy collisions @xcite , but it has been also demonstrated that some detectable effects could also be observed at low energy @xcite . this is the topic of the present paper . some authors have early underlined or suggested that the particles of the standard model could be able to escape out of our visible world @xcite . many effects can be considered and have been explored until now along this line of thought .

Suppose that you have an abstract for a scientific paper: we consider modified gravity models involving inverse powers of fourth - order curvature invariants . using these models equivalence to the theory of a scalar field coupled to a linear combination of the invariants , we investigate the properties of the propagating modes . even in the case for which the fourth derivative terms in the field equations vanish , we find that the second derivative terms can give rise to ghosts , instabilities , and superluminal propagation speeds . we establish the conditions which the theories must satisfy in order to avoid these problems in friedmann backgrounds , and show that the late - time attractor solutions generically exhibit superluminally propagating tensor or scalar modes . . And you have already written the first three sentences of the full article: the strong observational evidence for an accelerating universe @xcite has sparked a widespread search for a dynamical explanation . beyond a bare cosmological constant , a plethora of other models have been proposed , with quintessence - a dynamical scalar field that behaves essentially as a modern day inflaton field , - being perhaps the simplest example ( see @xcite ) . in this context , many potentials have been introduced that yield late - time acceleration and tracking behaviour ( see @xcite ) . among other approaches , modified gravity models have attracted great interest ( see @xcite ) but also some criticism , partly because they were introduced as purely phenomenological models , but more seriously because it was not clear that they possessed a satisfactory newtonian limit in the solar system , or that they were free of ghosts ( see @xcite ) . in this paper. Please generate the next two sentences of the article

, we investigate the propagating degrees of freedom of the so - called cddett model @xcite . there already exist detailed studies of the newtonian limit @xcite and the supernovae contraints @xcite for this model . here we derive conditions that they be free of ghosts , and that they have a real propagation speed less than or equal to that of light . as we review below

Suppose that you have an abstract for a scientific paper: imperative programmers often use cyclically linked trees in order to achieve o(1 ) navigation time to neighbours . some logic programmers believe that cyclic terms are necessary to achieve the same in logic - based languages . an old but little - known technique provides o(1 ) time and space navigation without cyclic links , in the form of reversible predicates . a small modification provides o(1 ) amortised time and space editing . [ firstpage ] . And you have already written the first three sentences of the full article: when imperative programmers think of lists , they commonly choose doubly linked lists , instead of the singly linked lists that logic and functional programmers use . in the same way , it is extremely common for trees to be given parent links , whether they are really needed or not . a typical c example might be .... typedef int datum ; typedef struct treerec * treeptr ; struct treerec { treeptr left , right , up , down ; datum datum ; } ; .... where ` down ' points to the first child of a node , ` up ' to its parents , and the children of a node form a doubly linked list with ` left ' and ` right ' pointers .. Please generate the next two sentences of the article

essentially this representation is required by the document object model @xcite , for example . cyclically linked trees in imperative languages such as java provide constant time navigation in any of the four directions ( up , down , left , right ) and also constant time and constant space editing ( insert , delete , replace ) .

Suppose that you have an abstract for a scientific paper: interference is a major performance bottleneck in heterogeneous network ( hetnet ) due to its multi - tier topological structure . we propose almost blank resource block ( abrb ) for interference control in hetnet . when an abrb is scheduled in a macro bs , a resource block ( rb ) with blank payload is transmitted and this eliminates the interference from this macro bs to the pico bss . we study a two timescale hierarchical radio resource management ( rrm ) scheme for hetnet with _ dynamic abrb _ control . the long term controls , such as dynamic abrb , are adaptive to the large scale fading at a rrm server for co - tier and cross - tier interference control . the short term control ( user scheduling ) is adaptive to the local channel state information within each bs to exploit the _ multi - user diversity_. the two timescale optimization problem is challenging due to the exponentially large solution space . we exploit the sparsity in the _ interference graph _ of the hetnet topology and derive structural properties for the optimal abrb control . based on that , we propose a _ two timescale alternative optimization _ solution for the user scheduling and abrb control . the solution has low complexity and is asymptotically optimal at high snr . simulations show that the proposed solution has significant gain over various baselines . heterogeneous network , dynamic abrb control , two timescale rrm . And you have already written the first three sentences of the full article: as hetnet provides flexible and efficient topology to boost spectral efficiency , it has recently aroused immense interest in both academia and industry . as illustrated in fig . [ fig : hetnet_2tiers ] , a hetnet consists of a diverse set of regular macro base stations ( bs ) overlaid with low power pico bss . since this overlaid structure may lead to severe interference problem , it is extremely critical to control interference via rrm in hetnet .. Please generate the next two sentences of the article

there has been much research conducted on rrm optimization for traditional cellular networks . in @xcite , the authors considered power and user scheduling in single - carrier cellular networks . in @xcite ,

Suppose that you have an abstract for a scientific paper: the length spectra of flat three - dimensional dielectric resonators of circular shape were determined from a microwave experiment . they were compared to a semiclassical trace formula obtained within a two - dimensional model based on the effective index of refraction approximation and a good agreement was found . it was necessary to take into account the dispersion of the effective index of refraction for the two - dimensional approximation . furthermore , small deviations between the experimental length spectrum and the trace formula prediction were attributed to the systematic error of the effective index of refraction approximation . in summary , the methods developed in this article enable the application of the trace formula for two - dimensional dielectric resonators also to realistic , flat three - dimensional dielectric microcavities and -lasers , allowing for the interpretation of their spectra in terms of classical periodic orbits . . And you have already written the first three sentences of the full article: open dielectric resonators have received great attention due to numerous applications @xcite , e.g. , as microlasers @xcite or as sensors @xcite , and as paradigms of open wave - chaotic systems @xcite . the size of dielectric microcavities typically ranges from a few to several hundreds of wavelengths . wave - dynamical systems that are large compared to the typical wavelength have been treated successfully with semiclassical methods .. Please generate the next two sentences of the article

these provide approximate solutions in terms of properties of the corresponding classical system . in the case of dielectric cavities , the corresponding classical system is an open dielectric billiard . inside

Suppose that you have an abstract for a scientific paper: we demonstrate a state reconstruction technique which provides either the wigner function or the density matrix of a field mode and requires only avalanche photodetectors , without any phase or amplitude discrimination power . it represents an alternative to quantum homodyne tomography of simpler implementation . . And you have already written the first three sentences of the full article: the characterization of states and operations at the quantum level plays a leading role in the development of quantum technology . a state reconstruction technique is a method that provides the complete description of a physical system upon the measurements of an observable or a set of observables @xcite . an effective reconstruction technique gives the maximum possible knowledge of the state , thus allowing one to make the best , at least the best probabilistic , predictions on the results of any measurement that may be performed on the system . at a first sight. Please generate the next two sentences of the article

, there is an unavoidable tradeoff between the complexity of the detection scheme and the amount of extractable information , which can be used to reconstruct the quantum state @xcite . currently , the most effective quantum state reconstruction technique for the radiation field is quantum homodyne tomography @xcite , which requires the measurement of a continuous set of field quadrature and allows for the reliable reconstruction of any quantity expressible in terms of an expectation value @xcite .

Suppose that you have an abstract for a scientific paper: in this paper the four - dimensional ( 4-d ) space - velocity cosmological general relativity of carmeli is developed by a general solution of the einstein field equations . the tolman metric is applied in the form @xmath0 where @xmath1 is the metric tensor . we use comoving coordinates @xmath2 , where @xmath3 is the hubble - carmeli time constant , @xmath4 is the universe expansion velocity and @xmath5 , @xmath6 and @xmath7 are the spatial coordinates . we assume that @xmath8 and @xmath9 are each functions of the coordinates @xmath10 and @xmath5 . the vacuum mass density @xmath11 is defined in terms of a cosmological constant @xmath12 , @xmath13 where the carmeli gravitational coupling constant @xmath14 , where @xmath15 is the speed of light in vacuum . this allows the definitions of the effective mass density @xmath16 and effective pressure @xmath17 where @xmath18 is the mass density and @xmath19 is the pressure . then the energy - momentum tensor @xmath20 , \label{abs : t_uv_eff}\ ] ] where @xmath21 is the 4-velocity . the einstein field equations are taken in the form @xmath22 where @xmath23 is the ricci tensor , @xmath24 is carmeli s gravitation constant , where @xmath25 is newton s constant and the trace @xmath26 . by solving the field equations ( [ abs : field - eqs - new ] ) a space - velocity cosmology is obtained analogous to the friedmann - lematre - robertson - walker space - time cosmology . we choose an equation of state such that @xmath27 with an evolving state parameter @xmath28 where @xmath29 is the scale factor and @xmath30 and @xmath31 are constants . carmeli s 4-d space - velocity cosmology is derived as a special case . . And you have already written the first three sentences of the full article: cosmological general relativity ( cgr ) is a 5-d time - space - velocity theory@xcite of the cosmos , for one dimension of cosmic time , three of space and one of the universe expansion velocity . cosmic time is taken to increase from the present epoch @xmath32 toward the big bang time @xmath33 , where @xmath3 is the hubble - carmeli time constant . the expansion velocity @xmath34 at the present epoch and increases toward the big bang . in this paper the cosmic time @xmath35. Please generate the next two sentences of the article

is held fixed ( @xmath36 ) and measurements are referred to the present epoch of cosmic time . this is a reasonable approach since the time duration over which observations are made is negligible compared to the travel time of the emitted light from the distant galaxy .

Suppose that you have an abstract for a scientific paper: we derive an analytical gauge - invariant formula between the polyakov loop @xmath0 and the dirac eigenvalues @xmath1 in qcd , i.e. , @xmath2 , in ordinary periodic square lattice qcd with odd - number temporal size @xmath3 . here , @xmath4 denotes the dirac eigenstate , and @xmath5 temporal link - variable operator . this formula is a dirac spectral representation of the polyakov loop in terms of dirac eigenmodes @xmath4 . because of the factor @xmath6 in the dirac spectral sum , this formula indicates negligibly small contribution of low - lying dirac modes to the polyakov loop in both confinement and deconfinement phases , while these modes are essential for chiral symmetry breaking . next , we find a similar formula between the wilson loop and dirac modes on arbitrary square lattices , without restriction of odd - number size . this formula suggests a small contribution of low - lying dirac modes to the string tension @xmath7 , or the confining force . these findings support no crucial role of low - lying dirac modes for confinement , i.e. , no direct one - to - one correspondence between confinement and chiral symmetry breaking in qcd , which seems to be natural because heavy quarks are also confined even without light quarks or the chiral symmetry . . And you have already written the first three sentences of the full article: since quantum chromodynamics ( qcd ) was established as the fundamental theory of strong interaction @xcite , it has been an important problem in theoretical physics to clarify color confinement and spontaneous chiral - symmetry breaking @xcite . however , in spite of many and various studies , these two nonperturbative phenomena have not been well understood directly from qcd . dynamical chiral - symmetry breaking in qcd is categorized as well - known spontaneous symmetry breaking , which widely appears in various phenomena in physics .. Please generate the next two sentences of the article

the standard order parameter of chiral symmetry breaking is the quark condensate @xmath8 , and it is directly related to low - lying dirac modes , as the banks - casher relation indicates @xcite . here , dirac modes are eigenmodes of the dirac operator @xmath9 , which directly appears in the qcd lagrangian .

Suppose that you have an abstract for a scientific paper: the masses and radii of low - magnetic field neutron stars can be measured by combining different observable quantities obtained from their x - ray spectra during thermonuclear x - ray bursts . one of these quantities is the apparent radius of each neutron star as inferred from the x - ray flux and spectral temperature measured during the cooling tails of bursts , when the thermonuclear flash is believed to have engulfed the entire star . in this paper , we analyze 13,095 x - ray spectra of 446 x - ray bursts observed from 12 sources in order to assess possible systematic effects in the measurements of the apparent radii of neutron stars . we first show that the vast majority of the observed x - ray spectra are consistent with blackbody functions to within a few percent . we find that most x - ray bursts follow a very well determined correlation between x - ray flux and temperature , which is consistent with the whole neutron - star surface emitting uniformly during the cooling tails . we develop a bayesian gaussian mixture algorithm to measure the apparent radii of the neutron stars in these sources , while detecting and excluding a small number of x - ray bursts that show irregular cooling behavior . this algorithm also provides us with a quantitative measure of the systematic uncertainties in the measurements . we find that those errors in the spectroscopic determination of neutron - star radii that are introduced by systematic effects in the cooling tails of x - ray bursts are in the range @xmath0% . such small errors are adequate to distinguish between different equations of state provided that uncertainties in the distance to each source and the absolute calibration of x - ray detectors do not dominate the error budget . . And you have already written the first three sentences of the full article: the thermal spectra of neutron stars during thermonuclear x - ray bursts have been used during the last three decades in numerous attempts to measure the neutron - star masses and radii ( e.g. , van paradijs 1978 , 1979 ; foster , fabian & ross 1986 ; sztajno et al . 1987 ; van paradijs & lewin 1987 ; damen et al . 1989 , 1990 ) . such efforts were often hampered by large systematic uncertainties in the estimated distances to the bursters and in the theoretical models for their x - ray spectra .. Please generate the next two sentences of the article

moreover , the relatively small number of x - ray bursts observed by early satellites from each individual source made it impossible to assess systematic uncertainties related to the degree of anisotropy of the thermonuclear burning on the neutron - star surface , or of the obscuration by and the reflection off the accretion flow . the situation has changed dramatically in the last few years .

Suppose that you have an abstract for a scientific paper: the x - ray emission from normal elliptical galaxies has two major components : soft ( @xmath0 kev ) emission from diffuse gas and harder ( @xmath1 kev ) emission from populations of accreting ( low - mass ) stellar x - ray binaries ( lmxb ) . if the lmxb population is intimately tied to the field stellar population in a galaxy , its aggregate x - ray luminosity is expected to be simply proportional to the optical luminosity of the galaxy . however , recent _ asca _ and _ chandra _ x - ray observations show that the global luminosities of lmxb components in ellipticals exhibit significant scatter ( a factor of @xmath24 ) at a given optical luminosity . this scatter may reflect a range of evolutionary stages among x - ray binary populations in elliptical galaxies of different ages . if so , the ratio of the global lmxb x - ray luminosity to the galactic optical luminosity , @xmath3 , may in principle be used to determine when the bulk of stars were formed in individual ellipticals . to test this , we compare variations in @xmath3 for lmxb populations in ellipticals to optically - derived estimates of stellar ages in the same galaxies . we find no correlation , which suggests that variations in @xmath3 are not a good age indicator for ellipticals . alternatively , lmxbs may be formed primarily in globular clusters ( through stellar tidal interactions ) , rather than comprise a subset of the primordial binary star population in a galactic stellar field . since elliptical galaxies exhibit a wide range of globular cluster populations for a given galaxian luminosity , this may induce a dispersion in the lmxb populations of ellipticals with similar optical luminosities . indeed , we find that @xmath3 ratios for lmxb populations are strongly correlated with the specific globular cluster frequencies in elliptical galaxies . this suggests that most lmxbs were formed in globular clusters . if so , _ chandra _ observations of central dominant galaxies with unusually large globular cluster populations.... And you have already written the first three sentences of the full article: the x - ray emission from normal elliptical galaxies has two major components : soft ( @xmath0 kev ) emission from diffuse gas and harder ( @xmath1 kev ) emission from populations of accreting ( low - mass ) stellar x - ray binaries ( lmxb ) . the x - ray properties of the lmxb component have been difficult to determine , due to their spatial confusion with diffuse gaseous emission and to spectral hardness which places much of the lmxb emission outside the effective bandpasses of most imaging x - ray satellite spectrometers . the presence of the lmxb component has been inferred in part through observations of spectral hardening in ellipticals with progressively smaller x - ray to optical luminosity ratios ( kim , fabbiano , & trinchieri 1992 ) , indicating that they have relatively little gas , exposing the harder lmxb component .. Please generate the next two sentences of the article

populations of lmxbs are also expected in ellipticals simply by analogy with detections of discrete lmxb sources in nearby spheroids such as the bulges and halos of our galaxy and m31 ( forman , jones & tucker 1985 ; canizares , fabbiano & trinchieri 1987 ) , as well as in the radio galaxy centaurus a ( turner et al . 1997 ) . a simple argument suggests that the total x - ray luminosities of lmxb populations in ellipticals might be proportional to the stellar luminosities of the galaxies : if the properties of low mass binary stellar systems ( such as the fraction of stars in binaries , the distributions of binary separations and mass ratios , etc . )

Suppose that you have an abstract for a scientific paper: we present the first dedicated x - ray study of the supernova remnant ( snr ) g32.8@xmath00.1 ( kes 78 ) with _ suzaku_. x - ray emission from the whole snr shell has been detected for the first time . the x - ray morphology is well correlated with the emission from the radio shell , while anti - correlated with the molecular cloud found in the snr field . the x - ray spectrum shows not only conventional low - temperature ( @xmath1 kev ) thermal emission in a non - equilibrium ionization state , but also a very high temperature ( @xmath2 kev ) component with a very low ionization timescale ( @xmath3 @xmath4 s ) , or a hard non - thermal component with a photon index @xmath5@xmath62.3 . the average density of the low - temperature plasma is rather low , of the order of @xmath7@xmath8 @xmath4 , implying that this snr is expanding into a low - density cavity . we discuss the x - ray emission of the snr , also detected in tev with h.e.s.s . , together with multi - wavelength studies of the remnant and other gamma - ray emitting snrs , such as w28 and rcw 86 . analysis of a time - variable source , 2xmm j185114.3@xmath0000004 , found in the northern part of the snr , is also reported for the first time . rapid time variability and a heavily absorbed hard x - ray spectrum suggest that this source could be a new supergiant fast x - ray transient . . And you have already written the first three sentences of the full article: supernova remnants ( snrs ) are believed to be the primary sites for cosmic ray acceleration up to the ` knee ' of the cosmic rays spectrum . x - ray observations revealed that shells of several young snrs are synchrotron x - ray emitters , implying that they are the acceleration sites of particles @xcite . on the other hand , the number of snrs with a synchrotron x - ray emitting shell is limited @xcite .. Please generate the next two sentences of the article

recent very high energy ( vhe ) gamma - ray observations with _ h.e.s.s . _ , _ magic _ , and _ veritas _ are continually revealing snrs as sites for energetic particles accelerated at snr shocks up to the tev range @xcite .

Suppose that you have an abstract for a scientific paper: recent observations of the diffuse galactic @xmath0-ray emission ( dge ) by the _ fermi _ large area telescope ( _ fermi_-lat ) have shown significant deviations , above a few gev until about 100 gev , from dge models that use the galprop code for the propagation of cosmic ray ( cr ) particles outside their sources in the galaxy and their interaction with the target distributions of the interstellar gas and radiation fields . the surplus of radiation observed is most pronounced in the inner galaxy , where the concentration of cr sources is strongest . the present study investigates this `` _ fermi_-lat galactic plane surplus '' by estimating the @xmath0-ray emission from the sources themselves , which is disregarded in the above dge models . it is shown that indeed the expected hard spectrum of crs , still confined in their sources ( scrs ) , can explain this surplus . the method is based on earlier studies regarding the so - called egret gev excess which by now is generally interpreted as an instrumental effect . the contribution from scrs is predicted to increasingly exceed the dge models also above 100 gev , up to @xmath0-ray energies of about ten tev , where the corresponding surplus exceeds the hadronic part of the dge by about one order of magnitude . above such energies the emission surplus should decrease again with energy due to the finite life - time of the assumed supernova remnant sources . observations of the dge in the inner galaxy at 15 tev with the milagro @xmath0-ray detector and , at tev energies , with the argo - ybj detector are interpreted to provide confirmation of a significant scr contribution to the dge . . And you have already written the first three sentences of the full article: the diffuse galactic @xmath0-ray emission ( dge ) from the full sky has recently been analyzed and compared with the observations with the _ fermi _ large area telescope ( _ fermi_-lat ) for high energies ( he ; @xmath1 ) @xcite . the dge had been modeled using the galprop code ( e.g. * ? ? ? * ; * ? ? ?. Please generate the next two sentences of the article

* ; * ? ? ? for a review , see @xcite .

Suppose that you have an abstract for a scientific paper: stellar multiplicity lies at the heart of many problems in modern astrophysics , including the physics of star formation , the observational properties of unresolved stellar populations , and the rates of interacting binaries such as cataclysmic variables , x - ray binaries , and type ia supernovae . however , little is known about the stellar multiplicity of field stars in the milky way , in particular about the differences in the multiplicity characteristics between metal - rich disk stars and metal - poor halo stars . in this study we perform a statistical analysis of @xmath014,000 f - type dwarf stars in the milky way through time - resolved spectroscopy with the sub - exposures archived in the sloan digital sky survey . we obtain absolute radial velocity measurements through template cross - correlation of individual sub - exposures with temporal baselines varying from minutes to years . these sparsely sampled radial velocity curves are analyzed using markov chain monte carlo techniques to constrain the very short - period binary fraction for field f - type stars in the milky way . metal - rich disk stars were found to be @xmath1 more likely to have companions with periods shorter than 12 days than metal - poor halo stars . . And you have already written the first three sentences of the full article: stellar multiplicity plays a crucial role in many fields of astronomy . star formation and evolution , galactic chemical evolution , nuclear astrophysics , and cosmology are all influenced by our understanding of the multiplicity properties of an underlying stellar population . binary interactions lead to phenomena as diverse as cataclysmic variables , classical novae , x - ray binaries , gamma - ray bursts , and type ia supernovae .. Please generate the next two sentences of the article

stellar interactions are also the cause of the anomalous surface abundances measured in ba stars , ch stars , and the majority of carbon - enhanced metal - poor stars @xcite . the rates of these phenomena depend on the multiplicity properties such as the fraction of stars with companions and the distributions of separations and mass ratios .

Suppose that you have an abstract for a scientific paper: observations and numerical magnetohydrodynamic ( mhd ) simulations indicate the existence of outflows and ordered large - scale magnetic fields in the inner region of hot accretion flows . in this paper we present the self - similar solutions for advection - dominated accretion flows ( adafs ) with outflows and ordered magnetic fields . stimulated by numerical simulations , we assume that the magnetic field has a strong toroidal component and a vertical component in addition to a stochastic component . we obtain the self - similar solutions to the equations describing the magnetized adafs , taking into account the dynamical effects of the outflow . we compare the results with the canonical adafs and find that the dynamical properties of adafs such as radial velocity , angular velocity and temperature can be significantly changed in the presence of ordered magnetic fields and outflows . the stronger the magnetic field is , the lower the temperature of the accretion flow will be , and the faster the flow rotates . the relevance to observations is briefly discussed . accretion , accretion discs magnetohydrodynamics : mhd ism : jets and outflow black hole physics . And you have already written the first three sentences of the full article: advection - dominated accretion flows ( hereafter adafs ) have been studied extensively ( e.g , narayan & yi 1994 , 1995 ; abramowicz et al . 1995 ; see narayan , mahadevan & quataert 1998 and kato , fukue & mineshige 1998 for reviews ) . it is now rather well established that this accretion mode exists in the quiescent and hard states of black hole x - ray binaries and low - luminosity active galactic nuclei ( see narayan 2005 , yuan 2007 , ho 2008 , and narayan & mcclintock 2008 for recent reviews ) .. Please generate the next two sentences of the article

adafs only exist below a critical mass accretion rate . below this accretion rate , the rate of radiative cooling is so weak that the viscous heating is balanced by the advection . with the increase of accretion rate ,

Suppose that you have an abstract for a scientific paper: we study the possibility that primordial magnetic fields generated in the transition between inflation and reheating posses magnetic helicity , @xmath0 . the fields are induced by stochastic currents of scalar charged particles created during the mentioned transition . we estimate the rms value of the induced magnetic helicity by computing different four - point sqed feynman diagrams . for any considered volume , the magnetic flux across its boundaries is in principle non null , which means that the magnetic helicity in those regions is gauge dependent . we use the prescription given by berger and field and interpret our result as the difference between two magnetic configurations that coincide in the exterior volume . in this case the magnetic helicity gives only the number of magnetic links inside the considered volume . we calculate a concrete value of @xmath0 for large scales and analyze the distribution of magnetic defects as a function of the scale . those defects correspond to regular as well as random fields in the considered volume . we find that the fractal dimension of the distribution of topological defects is @xmath1 . we also study if the regular fields induced on large scales are helical , finding that they are and that the associated number of magnetic defects is independent of the scale . in this case the fractal dimension is @xmath2 . we finally estimate the intensity of fields induced at the horizon scale of reheating , and evolve them until the decoupling of matter and radiation under the hypothesis of inverse cascade of magnetic helicity . the resulting intensity is high enough and the coherence length long enough to have an impact on the subsequent process of structure formation . . And you have already written the first three sentences of the full article: large scale magnetic fields are widespread in the universe . from galaxies to clusters of galaxies coherent magnetic fields are detected , with intensities that range from @xmath3gauss to tenth of @xmath3gauss . our galaxy as well as nearby galaxies show magnetic fields coherent on the scale of the whole structure , while in galaxy clusters the coherent length is much less than the cluster s size @xcite . a remarkable fact recently discovered by observations , is that high redshift galaxies also posses coherent fields with the same intensitis as present day galaxies @xcite .. Please generate the next two sentences of the article

this result challenges the generally accepted mechanism of magnetogenesis , namely the amplification of a primordial field of @xmath4 gauss by a mean field dynamo @xcite acting during a time of the order of the age of the structure : either the primordial fields are more intense so the galactic dynamo saturates in a shorter time , or the dynamo does not work as it is currently thought . it is hoped that future observations of high redshift environments will shed more light on the features of primordial magnetic fields @xcite . in view of the lack of success in finding a primordial mechanism for magnetogenesis that produces a sufficiently intense field , either to feed an amplifying mechanism , or to directly explain the observations ( see refs .

Suppose that you have an abstract for a scientific paper: we present statistics ( s - statistics ) based only on random variable ( not random value ) with a mean squared error of mean estimation as a concept of error . . And you have already written the first three sentences of the full article: [ sec:1 ] * remark . * notation @xmath0 is equivalent to @xmath1 where @xmath2 } _ { n\times 1 } \ , & \rho & = & \rho_{ij } & = & \underbrace { \left [ \begin{array}{c } \rho_{1j } \\ \vdots \\ \rho_{nj } \\ \end{array } \right ] } _ { n \times 1 } \ . \end{array}\ ] ] notation @xmath3 is equivalent to @xmath4 where @xmath5}_{n \times n } } \ . \end{array}\ ] ] let us consider ( e.g. for @xmath6 ) variance of the difference @xmath7 of two random variables @xmath8 and @xmath9 , where @xmath10 , in terms of covariance @xmath11 introducing the estimation statistics @xmath12 @xmath13 in terms of correlation function @xmath14 @xmath15 if @xmath16 and @xmath17 or @xmath18 if @xmath19 and @xmath20 the unbiasedness constraint ( i condition ) @xmath21 is equivalent to @xmath22 the minimization constraint @xmath23 where @xmath24 produces @xmath25 equations in the @xmath26 unknowns : kriging weights @xmath27 and a lagrange parameter @xmath28 ( ii condition ) @xmath29}_{n\times(n+1 ) } } & \cdot & \underbrace { \left [ \begin{array}{c } \omega_j^1. Please generate the next two sentences of the article

\\ \vdots \\ \omega_j^n \\ \mu_j \\ \end{array } \right ] } _ { ( n+1)\times 1 } & = & \underbrace { \left [ \begin{array}{c } \rho_{1j } \\ \vdots \\ \rho_{nj } \\ \end{array } \right ] } _ { n \times 1 } \end{array}\ ] ] multiplied by @xmath30 @xmath31 and substituted into @xmath32 @xmath33 ^ 2\}-\underbrace{e^2\{v_j-\hat{v}_j\}}_0 \\ & = & e\{[(v_j - m)-(\hat{v}_j - m)]^2\ } \\ & = & e\{[v_j - m]^2\}-2(e\{v_j\hat{v}_j\}-m^2)+e\{[\hat{v}_j - m]^2\ } \\ & = & \sigma^2 -2 \sigma^2 |\omega^i_j \rho_{ij}| + \sigma^2 |\omega^i_j \rho_{ii } \omega^i_j| \\ & = & \sigma^2 \pm 2 \sigma^2 \omega^i_j \rho_{ij } \mp \sigma^2 \omega^i_j \rho_{ii } \omega^i_j \end{array}\ ] ] give the minimized variance of the field @xmath8 under estimation @xmath34 ^ 2\ } = \sigma^2 ( 1 \pm ( \omega^i_j \rho_{ij } + \mu_j ) ) \ ] ] and these two conditions produce @xmath26 equations in the @xmath26 unknowns @xmath35}_{(n+1)\times(n+1 ) } } & \cdot & \underbrace { \left [ \begin{array}{c } \omega_j^1 \\ \vdots \\ \omega_j^n \\ \mu_j \\ \end{array } \right ] } _ { ( n+1)\times 1 } & = & \underbrace { \left [ \begin{array}{c } \rho_{1j } \\ \vdots \\ \rho_{nj } \\ 1 \\ \end{array } \right ] } _ { ( n+1 ) \times 1 } \ . \end{array}\ ] ] since @xmath36 then @xmath37 and ( since ) @xmath38 then @xmath39 the minimized variance of the field @xmath8 under estimation @xmath34 ^ 2\ } = \sigma^2 ( 1\pm(\omega^i_j \rho_{ij } + \mu_j))\ ] ] has known asymptotic property @xmath40 ^ 2\ } = \lim_{n \rightarrow \infty } e\{[v_j-\omega^i_j v_i]^2\ } = e\{[v_j - m]^2\ } = \sigma^2 \ .\ ] ]

Suppose that you have an abstract for a scientific paper: we consider the derived categories of modules over a certain family @xmath0 ( @xmath1 ) of graded rings , and floer cohomology of lagrangian intersections in the symplectic manifolds which are the milnor fibres of simple singularities of type @xmath2 we show that each of these two rather different objects encodes the topology of curves on an @xmath3-punctured disc . we prove that the braid group @xmath4 acts faithfully on the derived category of @xmath0-modules , and that it injects into the symplectic mapping class group of the milnor fibers . the philosophy behind our results is as follows . using floer cohomology , one should be able to associate to the milnor fibre a triangulated category ( its construction has not been carried out in detail yet ) . this triangulated category should contain a full subcategory which is equivalent , up to a slight difference in the grading , to the derived category of @xmath0-modules . the full embedding would connect the two occurrences of the braid group , thus explaining the similarity between them . . And you have already written the first three sentences of the full article: this paper investigates the connection between symplectic geometry and those parts of representation theory which revolve around the notion of categorification . the existence of such a connection , in an abstract sense , follows from simple general ideas . the difficult thing is to make it explicit . on the symplectic side ,. Please generate the next two sentences of the article

the tools needed for a systematic study of this question are not yet fully available . therefore we concentrate on a single example , which is just complicated enough to indicate the depth of the relationship .

Suppose that you have an abstract for a scientific paper: the difficulty in producing precisely timed and controlled quantum gates is a significant source of error in many physical implementations of quantum computers . here we introduce a simple universal primitive , adiabatic gate teleportation , which is robust to timing errors and many control errors and maintains a constant energy gap throughout the computation above a degenerate ground state space . notably this construction allows for geometric robustness based upon the control of two independent qubit interactions . further , our piecewise adiabatic evolution easily relates to the quantum circuit model , enabling the use of standard methods from fault - tolerance theory for establishing thresholds . building a quantum computer is a daunting task , so much so that it is not even clear which of a plethora of architectures is the most physically viable . in addition to the standard pulsed implementation of the circuit model of quantum computation ( qc ) , other possible architectures include measurement - based qc @xcite , universal adiabatic qc @xcite , and holonomic qc @xcite . of these , adiabatic qc has recently drawn considerable attention , in part because of its deep connection to computational complexity problems @xcite , but also due to the advantages this model possesses with respect to decoherence and control @xcite . similarly holonomic qc has attracted interest because of the geometric robustness of control in this scheme . motivated by some of the benefits of adiabatic and holonomic qc , we introduce a new model of qc which is a hybrid between the adiabatic , circuit , and holonomic models . this model uses nothing but adiabatic quantum evolution , but instead of using a single interpolation between an initial and final hamiltonian , we use piecewise adiabatic evolutions whose individual parts implement a step in a quantum circuit . we achieve this by introducing a new primitive : adiabatic gate teleportation ( agt ) . our route to agt proceeds by merging two.... And you have already written the first three sentences of the full article: here we show that if one uses an isotropic exchange interaction instead of the anisotropic interactions in the teleportation protocol one can also perform adiabatic teleportation . in this case the initial hamiltonian is @xmath90\end{aligned}\ ] ] and the final hamiltonian is @xmath91\end{aligned}\ ] ] where we have expressed these hamiltonians in terms of the encoded operations given in eq . 1 of the main text . these equations show that now instead of two decoupled encoded qubits , the encoded qubits are coupled .. Please generate the next two sentences of the article

however notice that the initial ground state is the @xmath92 eigenstate of @xmath23 and @xmath24 and the final ground state is the @xmath92 eigenstate of the @xmath27 and @xmath28 , just as in anisotropic exchange protocol , but with the signs flipped . further there are no level crossing in a linear ramping between these two hamiltonians , and the gap is a constant @xmath93 occurring at the midpoint of this evolution .

Suppose that you have an abstract for a scientific paper: recent results on charmonium decays are reviewed which includes two- , three- and four - body decays of @xmath0 states , observations of y(4260 ) through @xmath1 transitions , precise measurements of @xmath2 , @xmath3 as well as @xmath4 . . And you have already written the first three sentences of the full article: decays of a bound state of a quark and its anti - quark , quarkonium , provide an excellent laboratory for studying qcd . particularly , heavy quarkonia such as charmonium states are less relativistic , thus play a special role in probing strong interactions . cleo recently has accumulated data taken at the @xmath5 resonance , providing a total of 27 m @xmath5 decays . with the combination of this large statistical sample and the excellent cleo detector , we will explore an unprecedented world of charmonia .. Please generate the next two sentences of the article

while many analyses are currently being carried out , in this note we present recent results on multi - body @xmath0 decays which employed the pre - existing 3 m @xmath5 sample . we also present recent studies on decays of one of the exotic states , y(4260 ) , as well as precision measurement on @xmath2 that has an implication on properties of x(3872 ) . finally , based on the full sample of @xmath5 data

Suppose that you have an abstract for a scientific paper: using the mathisson - papapetrou - dixon ( mpd ) equations , we investigate the trajectories of a spinning particle starting near @xmath0 in a kerr field and moving with the velocity close to the velocity of light ( @xmath0 is the boyer - lindquist radial coordinate of the counter - rotation circular photon orbits ) . first , as a partial case of these trajectories , we consider the equatorial circular orbit with @xmath1 . this orbit is described by the solution that is common for the rigorous mpd equations and their linear spin approximation . then different cases of the nonequatorial motions are computed and illustrated by the typical figures . all these orbits exhibit the effects of the significant gravitational repulsion that are caused by the spin - gravity interaction . possible applications in astrophysics are discussed . . And you have already written the first three sentences of the full article: the geodesics in a kerr metric are considered in the classical books on general relativity [ 13 ] . some recent papers are devoted to more detailed study of geodesics on kerr s black hole with the aim to elucidate the mechanism of jet formation [ 4 ] , and to analyze the possibility of particle acceleration to arbitrary high energy [ 5 ] . the complete sets of analytic solutions of the geodesic equation in axially symmetric space - time are given in [ 6 ] .. Please generate the next two sentences of the article

however , the description of particle motion by geodesics is restricted to a spinless particle . the motion of a spinning test particle is described by the mathisson - papapetrou - dixon equations [ 79 ] : @xmath2 @xmath3 where @xmath4 is the particle s 4-velocity , @xmath5 is the tensor of spin , @xmath6 and @xmath7 are , respectively , the mass and the covariant derivative with respect to the particle s proper time @xmath8 ; @xmath9 is the riemann curvature tensor ( units @xmath10 are used ) . it is necessary to add a supplementary condition to eqs .

Suppose that you have an abstract for a scientific paper: we present a search for o i in the spectra of nine @xmath0 qsos taken with keck / hires . we detect six systems with @xmath1 in the redshift intervals where o i @xmath2 falls redward of the ly@xmath3 forest . four of these lie towards sdss j1148 + 5251 ( @xmath4 ) . this imbalance is unlikely to arise from variations in sensitivity among our data or from a statistical fluctuation . the excess o i occurs over a redshift interval that also contains transmission in ly@xmath3 and ly@xmath5 . therefore , if these o i systems represent pockets of neutral gas , then they must occur within or near regions of the igm that are highly ionized . in contrast , no o i is detected towards sdss j1030 + 0524 ( @xmath6 ) , whose spectrum shows complete absorption in ly@xmath3 and ly@xmath5 over @xmath7 . assuming no ionization corrections , we measure mean abundance ratios @xmath8 \rangle = -0.04 \pm 0.06 $ ] , @xmath9 \rangle = -0.31 \pm 0.09 $ ] , and @xmath10 \rangle = -0.34 \pm 0.07 $ ] ( @xmath11 ) , which are consistent with enrichment dominated by type ii supernovae . the o / si ratio limits the fraction of silicon in these systems contributed by metal - free very massive stars to @xmath12 , a result which is insensitive to ionization corrections . the ionic comoving mass densities along the @xmath13 sightlines , including only the detected systems , are @xmath14 , @xmath15 , and @xmath16 . . And you have already written the first three sentences of the full article: the state of the intergalactic medium ( igm ) at redshift @xmath17 remains under considerable debate . significant transmitted flux in the ly@xmath3 forest at @xmath18 means that the igm must have been highly ionized by at least @xmath19 gyr after the big bang @xcite . each of the four known qsos at @xmath20 show gunn - peterson troughs @xcite over at least a narrow redshift interval @xcite . this complete lack of transmitted flux has been interpreted as an indication that the tail end of cosmic reionization may extend to @xmath21 .. Please generate the next two sentences of the article

however , @xcite found the evolution of transmitted flux over @xmath22 to be consistent with a smoothly decreasing ionization rate and not indicative of a sudden jump in the ly@xmath3 optical depth at @xmath23 . significant variations in the fraction of transmitted flux are common among sightlines at the same redshift @xcite . while the spectrum of sdss j1030 + 0524 ( @xmath6 ) shows complete absorption in ly@xmath3 and ly@xmath5 over a redshift interval @xmath24 @xcite , transmitted flux appears over the same redshifts in the ly@xmath3 , ly@xmath5 , and ly@xmath25 forests of sdss j1148 + 5251 ( @xmath4 ) @xcite .

Suppose that you have an abstract for a scientific paper: we summarize the progress in neutrino astrophysics and emphasize open issues in our understanding of neutrino flavor conversion in media . we discuss solar neutrinos , core - collapse supernova neutrinos and conclude with ultra - high energy neutrinos . . And you have already written the first three sentences of the full article: nature has provided us with a variety of neutrino sources , from the not yet observed 1.9 k cosmological background to the icecube pev neutrinos @xcite , whose origin is still mysterious . neutrinos are intriguing weakly interacting particles . after 1998 many unknown properties have been determined thanks to the discovery of neutrino oscillations , first proposed in @xcite and observed by the super - kamiokande experiment using atmospheric neutrinos @xcite .. Please generate the next two sentences of the article

this discovery is fundamental for particle physics , for astrophysics and for cosmology . neutrino oscillations is an interference phenomenon among the @xmath0 mass eigenstates , that occurs if neutrinos are massive and if the mass ( propagation basis ) and the flavor ( interaction basis ) do not coincide .

Suppose that you have an abstract for a scientific paper: rumour detection is hard because the most accurate systems operate retrospectively , only recognising rumours once they have collected repeated signals . by then the rumours might have already spread and caused harm . we introduce a new category of features based on novelty , tailored to detect rumours early on . to compensate for the absence of repeated signals , we make use of news wire as an additional data source . unconfirmed ( novel ) information with respect to the news articles is considered as an indication of rumours . additionally we introduce pseudo feedback , which assumes that documents that are similar to previous rumours , are more likely to also be a rumour . comparison with other real - time approaches shows that novelty based features in conjunction with pseudo feedback perform significantly better , when detecting rumours instantly after their publication . . And you have already written the first three sentences of the full article: social media has evolved from friendship based networks to become a major source for the consumption of news ( nist , 2008 ) . on social media , news is decentralised as it provides everyone the means to efficiently report and spread information . in contrast to traditional news wire , information on social media is spread without intensive investigation , fact and background checking .. Please generate the next two sentences of the article

the combination of ease and fast pace of sharing information provides a fertile breeding ground for rumours , false- and disinformation . social media users tend to share controversial information in - order to verify it , while asking about for the opinions of their followers ( zhao et .

Suppose that you have an abstract for a scientific paper: static properties of a bose - fermi mixture of trapped potassium atoms are studied in terms of coupled gross - pitaevskii and thomas - fermi equations for both repulsive and attractive bose - fermi interatomic potentials . qualitative estimates are given for solutions of the coupled equations , and the parameter regions are obtained analytically for the boson - density profile change and for the boson / fermion phase separation . especially , the parameter ratio @xmath0 is found that discriminates the region of the large boson - profile change . these estimates are applied for numerical results for the potassium atoms and checked their consistency . it is suggested that a small fraction of fermions could be trapped without an external potential for the system with an attractive boson - fermion interaction . = -5 mm . And you have already written the first three sentences of the full article: recent development in the cooling and trapping technique of atoms and the following success in achieving the bose - einstein condensation of alkali atoms@xcite have now opened up a new era in the progress in quantum physics . while the condensed system serves as a testing ground for a research in fundamental problems of quantum mechanics , it also offers a new example of finite quantum many - body systems such as hadrons , nuclei and microclusters . an important characteristic of the trapped alkali atoms is that it is a dilute system of weakly interacting particles and an ideal place to test genuine properties of condensed systems predicted by theories .. Please generate the next two sentences of the article

along with a further progress in the study of bose - einstein condensed systems , a similar technique is being extended to create a degenerate gas of fermionic atoms , where a number of theoretical studies have been made@xcite . to realize such a degenerate fermionic system that requires a still lower temperature than bose systems , the technique of sympathetic cooling has been investigated@xcite : the cooling mechanism through the collisions with coexisting cold bose particles in a polarized boson - fermion mixture , where the fermion - fermion interaction is less effective .

Suppose that you have an abstract for a scientific paper: after a short review of the recent developments in studies of neutrino - nucleus interactions , the predictions for double - differential and integrated charged current - induced quasielastic cross sections are presented within two different relativistic approaches : one is the so - called susa method , based on the superscaling behavior exhibited by electron scattering data ; the other is a microscopic model based on relativistic mean field theory , and incorporating final - state interactions . the role played by the meson - exchange currents in the two - particle two - hole sector is explored and the results are compared with the recent miniboone data . . And you have already written the first three sentences of the full article: the analysis and interpretation of ongoing and future neutrino oscillation experiments strongly rely on the nuclear modeling for describing the interaction of neutrinos and anti - neutrinos with the detector . moreover , neutrino - nucleus scattering has recently become a matter of debate in connection with the possibility of extracting information on the nucleon axial mass . specifically , the data on muon neutrino charged - current quasielastic ( ccqe ) cross sections obtained by the miniboone collaboration @xcite are substantially underestimated by the relativistic fermi gas ( rfg ) prediction .. Please generate the next two sentences of the article

this has been ascribed either to effects in the elementary neutrino - nucleon interaction , or to nuclear effects . the most poorly known ingredient of the single nucleon cross section is the cutoff parameter @xmath0 employed in the dipole prescription for the axial form factor of the nucleon , which can be extracted from @xmath1 and @xmath2 scattering off hydrogen and deuterium and from charged pion electroproduction .

Suppose that you have an abstract for a scientific paper: in this work , numerical simulations were used to investigate the gravitational stochastic background produced by coalescences occurring up to @xmath0 of double neutron star systems . the cosmic coalescence rate was derived from monte carlo methods using the probability distributions for forming a massive binary and to occur a coalescence in a given redshift . a truly continuous background is produced by events located only beyond the critical redshift @xmath1 . events occurring in the redshift interval @xmath2 give origin to a popcorn " noise , while those arising closer than @xmath3 produce a shot noise . the gravitational density parameter @xmath4 for the continuous background reaches a maximum around 670 hz with an amplitude of @xmath5 , while the popcorn " noise has an amplitude about one order of magnitude higher and the maximum occurs around a frequency of 1.2 khz . the signal is below the sensitivity of the first generation of detectors but could be detectable by the future generation of ground based interferometers . correlating two coincident advanced - ligo detectors or two ego interferometers , the expected s / n ratio are respectively 0.5 and 10 . . And you have already written the first three sentences of the full article: the merger of two neutron stars , two black holes or a black hole and a neutron star are among the most important sources of gravitational waves ( gw ) , due to the huge energy released in the process . in particular , the coalescence of double neutron stars ( dns ) may radiate about 10@xmath6 erg in the last seconds of their inspiral trajectory , at frequencies up to 1.4 - 1.6 khz , range covered by most of the ground - based laser interferometers like virgo @xcite , ligo @xcite , geo @xcite or tama @xcite . besides the amount of energy involved in these events , the rate at which they occur in the local universe is another parameter characterizing if these mergings are or not potential interesting sources of gw . in spite of the large amount of work performed in the past years , uncertainties persist in estimates of the dns coalescence rate . in a previous investigation , we have revisited this question @xcite , taking into account the galactic star formation history derived directly from observations and including the contribution of elliptical galaxies when estimating the mean merging rate in the local universe .. Please generate the next two sentences of the article

based on these results , we have predicted a detection rate of one event every 125 and 148 years by initial ligo and virgo respectively and up to 6 detections per year in their advanced configurations . besides the emission produced by the coalescence of the nearest dns , the superposition of a large number of unresolved sources at high redshifts will produce a stochastic background of gw . in the past years , different astrophysical processes susceptible to generate a stochastic background have been investigated . on the one hand , distorted black holes @xcite , bar mode emission from young neutron stars @xcite are examples of sources able to generate a shot noise ( time interval between events large in comparison with duration of a single event ) , while supernovas or hypernovas @xcite are expected to produce an intermediate popcorn " noise . on the other hand ,

Suppose that you have an abstract for a scientific paper: we derive a formula describing the adiabatically pumped charge through an interacting quantum dot within the scattering matrix and green s function approach . we show that when the tunneling rates between the leads and the dot are varied adiabatically in time , both in modulus and phase , the current induced in the dot consists of two terms , the pumping current and a rectification - like term . the last contribution arises from the time - derivative of the tunneling phase and can have even or odd parity with respect to the pumping phase @xmath0 . the rectification - like term is also discussed in relation to some recent experiments in quantum - dots . . And you have already written the first three sentences of the full article: the idea of quantum pumping , i.e. of producing a dc current at zero bias voltage by time periodic modulation of two system parameters , dates back to the work of thouless @xcite . if the parameters change slowly as compared to all internal time scales of the system , the pumping is _ adiabatic _ , and the average charge per period does not depend on the detailed time dependence of the parameters . using the concept of emissivity proposed by bttiker et al.@xcite , brouwer@xcite related the charge pumped in a period to the derivatives of the instantaneous scattering matrix of the conductor with respect to the time - varying parameters . since then , a general framework to compute the pumped charge through a conductor has been developed for noninteracting electrons@xcite .. Please generate the next two sentences of the article

the interest in the pumping phenomenon has shifted then to the experimental@xcite investigations of confined nanostructures , as quantum dots , where the realization of the periodic time - dependent potential can be achieved by modulating gate voltages applied to the structure@xcite . in case of interacting electrons the computation of the pumped charge becomes rather involved and few works have addressed this issue for different systems@xcite and in specific regimes . as for the case of interacting quantum dots ,