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Suppose that you have an abstract for a scientific paper: we describe how the non - local regularization can be implemented in the calculation of solitons in the nambu jona - lasinio model as well as in the equivalent linear @xmath0-model . we investigate different forms of regulators and show that the 3-momentum cut - off leads to serious conceptual difficulties . . And you have already written the first three sentences of the full article: this work was done together with georges ripka and wojciech broniowski . solitons corresponding to baryons have been found in several chiral quark models . many of these solutions turn out to be unstable against collapse unless additional constraints are introduced in the model .. Please generate the next two sentences of the article

the well known examples are the linear njl model with proper time regularization @xcite and the linear @xmath0-model with sea quarks @xcite . even in the linear @xmath0-model with only valence quarks the energy of the soliton becomes too low for any choice of model parameters if one goes beyond the mean field approximation .

Suppose that you have an abstract for a scientific paper: new generation cellular networks have been forced to support high data rate communications . the demand for high bandwidth data services has rapidly increased with the advent of bandwidth hungry applications . to fulfill the bandwidth requirement , high throughput backhaul links are required . microwave radio links operating at high frequency bands are used to fully exploit the available spectrum . generating high carrier frequency becomes problematic due to the hardware limitations . non - ideal oscillators both at the transmitter and the receiver introduces time varying phase noise which interacts with the transmitted data in a non - linear fashion . phase noise becomes a detrimental problem in digital communication systems and needs to be estimated and compensated . in this thesis receiver algorithms are derived and evaluated to mitigate the effects of the phase noise in digital communication systems . the thesis is organized as follows : in chapter [ chap : siso - model ] phase noise estimation in single - input single - output ( siso ) systems is investigated . first , a hard decision directed extended kalman filter ( ekf ) is derived and applied to track time varying phase noise for an uncoded system . next , the problem of phase noise estimation for coded siso system is investigated . an iterative receiver algorithm performing code - aided turbo synchronization is derived using the expectation maximization ( em ) framework . two soft - decision directed estimators in the literature based on kalman filtering , the kalman filter and smoother with maximum likelihood average ( ks - mla ) and the extended kalman filter and smoother ( eks ) , are evaluated . low density parity check ( ldpc ) codes are proposed to calculate marginal a posteriori probabilities and to construct soft decision symbols . error rate performance of both estimators , the ks - mla and the eks , are determined and compared through simulations . simulations indicate that comparison on the performance of.... And you have already written the first three sentences of the full article: i would first like to thank my supervisors hani mehrpouyan and alexandre graell i amat for their support and guidance during the whole thesis process . i highly appreciate their attitude towards me . they have taught me how an academic should approach the problems in the field of research .. Please generate the next two sentences of the article

they have also trusted me and given me a lot of freedom . they respect my independent and somehow arrogant way of performing research .

Suppose that you have an abstract for a scientific paper: a significant observational effort has been directed to unveil the nature of the so - called dark energy . however , given the large number of theoretical possibilities , it is possible that such a task can not be performed on the basis only of the observational data . in this article we discuss some thermodynamic properties of this energy component assuming a general time - dependent equation - of - state parameter @xmath0 , where @xmath1 and @xmath2 are constants and @xmath3 may assume different forms . we show that very restrictive bounds can be placed on the @xmath4 - @xmath5 space when current observational data are combined with the thermodynamic constraints derived . . And you have already written the first three sentences of the full article: the observational evidence for an acceleration of the expansion of the universe is now overwhelming , although the precise cause of this phenomenon is still unknown ( see , e.g. , @xcite for recent reviews ) . in this concern , and besides the need for more accurate estimates of cosmological parameters , the current state of affairs also brings to light some other important aspects regarding the physics of the mechanism behind cosmic acceleration . certainly , one of these aspects concerns the thermodynamical behavior of a dark energy - dominated universe , and questions such as `` what is the thermodynamic behavior of the dark energy in an expanding universe ? '' or , more precisely , `` what is its temperature evolution law ? '' must be answered in the context of this new conceptual set up . another interesting aspect in this discussion is whether thermodynamics in the accelerating universe can place constraints on the time evolution of the dark energy and can also reveal some physical properties of this energy component .. Please generate the next two sentences of the article

the aim of this paper is twofold . first , to derive physical constraints on the dark energy from the second law of thermodynamics and to deduce the temperature evolution law for a dark component with a general equation - of - state ( eos ) parameter @xmath6 ; second , to perform a joint statistical analysis involving current observational data together with the thermodynamic bounds on @xmath6 . to do that , we assume the following generalized formula for the time evolution of @xmath6 @xcite @xmath7 which recovers some well - known eos parameterizations in the following limits : @xmath8 where @xmath9 and @xmath10 stand for the dark energy pressure and energy density , respectively ( see also @xcite for other eos parameterizations ) .

Suppose that you have an abstract for a scientific paper: single - crystal diamond cavity optomechanical devices are a promising example of a hybrid quantum system : by coupling mechanical resonances to both light and electron spins , they can enable new ways for photons to control solid state qubits . however , realizing cavity optomechanical devices from high quality diamond chips has been an outstanding challenge . here we demonstrate single - crystal diamond cavity optomechanical devices that can enable photon - phonon - spin coupling . cavity optomechanical coupling to @xmath0 frequency ( @xmath1 ) mechanical resonances is observed . in room temperature ambient conditions , these resonances have a record combination of low dissipation ( mechanical quality factor , @xmath2 ) and high frequency , with @xmath3 sufficient for room temperature single phonon coherence . the system exhibits high optical quality factor ( @xmath4 ) resonances at infrared and visible wavelengths , is nearly sideband resolved , and exhibits optomechanical cooperativity @xmath5 . the devices potential for optomechanical control of diamond electron spins is demonstrated through radiation pressure excitation of mechanical self - oscillations whose 31 pm amplitude is predicted to provide 0.6 mhz coupling rates to diamond nitrogen vacancy center ground state transitions ( 6 hz / phonon ) , and @xmath6 stronger coupling rates to excited state transitions . . And you have already written the first three sentences of the full article: diamond cavity optomechanical devices are an attractive platform for controlling interactions between light , vibrations , and electrons that underly future hybrid quantum technologies @xcite . their potential arises from diamond s exceptional mechanical and optical properties @xcite combined with its ability to host color centers such as the nitrogen - vacancy ( nv ) whose electron spins are excellent qubits that can be manipulated by local mechanical strain fields @xcite . recently , piezoelectric actuation of bulk @xcite and nanomechanical @xcite diamond resonators has been used to demonstrate phononic spin control .. Please generate the next two sentences of the article

cavity optomechanics @xcite harnesses optical forces in place of piezoelectric actuation , allowing coherent phonon state manipulation @xcite of ghz frequency mechanical resonators with quantum limited sensitivity @xcite . these phonons can be made resonant with nv center electron spin transitions that are central to proposals for spin

Suppose that you have an abstract for a scientific paper: we use hopf algebras to prove a version of the littlewood - richardson rule for skew schur functions , which implies a conjecture of assaf and mcnamara . we also establish skew littlewood - richardson rules for schur @xmath0- and @xmath1-functions and noncommutative ribbon schur functions , as well as skew pieri rules for @xmath2-schur functions , dual @xmath2-schur functions , and for the homology of the affine grassmannian of the symplectic group . assaf and mcnamara @xcite recently used combinatorics to give an elegant and surprising formula for the product of a skew schur function and a complete homogeneous symmetric function . their paper included a conjectural skew version of the littlewood - richardson rule , and also an appendix by one of us ( lam ) with a simple algebraic proof of their formula . we show how these formulas and much more are special cases of a simple formula that holds for any pair of dual hopf algebras . we first establish this hopf - algebraic formula , and then apply it to obtain formulas in some well - known hopf algebras in combinatorics . . And you have already written the first three sentences of the full article: we assume basic familiarity with hopf algebras , as found in the opening chapters of the book @xcite . let , be a pair of dual hopf algebras over a field @xmath3 . this means that there is a nondegenerate pairing @xmath4 for which the structure of @xmath5 is dual to that of @xmath6 and vice - versa .. Please generate the next two sentences of the article

for example , @xmath6 could be finite - dimensional and @xmath5 its linear dual , or @xmath6 could be graded with each component finite - dimensional and @xmath5 its graded dual . these algebras naturally act on each other @xcite : suppose that @xmath7 and @xmath8 and set @xmath9 ( we use sweedler notation for the coproduct , @xmath10 . )

Suppose that you have an abstract for a scientific paper: the foundations of time asymmetric quantum theory are reviewed and are applied to the construction of relativistic gamow vectors . relativistic gamow vectors are obtained from the resonance pole of the @xmath0-matrix and furnish an irreducible representation of the poincar semigroup . they have all the properties needed to represent relativistic quasistable particles and can be used to fix the definition of mass and width of relativistic resonances like the @xmath1-boson . most remarkably , they have only a semigroup time evolution into the forward light cone expressing time asymmetry on the microphysical level . 1.5 cm 0.5 cm physics department + the university of texas at austin + austin , texas 78712 , usa . And you have already written the first three sentences of the full article: in classical physics one has time symmetric dynamical equations with time asymmetric boundary conditions @xcite . these time asymmetric boundary conditions come in pairs : given one time asymmetric boundary condition , its time reversed boundary condition can also be formulated mathematically . for example in classical electrodynamics one has retarded and advanced solutions of the time symmetric dynamical ( maxwell ) equations or in general relativity one has time asymmetric big bang and big crunch solutions of einstein s time symmetric equation . except for a few prominent cases of pedagogical importance ( e.g. stationary states or cyclic evolutions ) ,. Please generate the next two sentences of the article

the physics of our world is predominantly time - asymmetric . somehow nature chooses one of the pair of time asymmetric boundary conditions .

Suppose that you have an abstract for a scientific paper: given a zero - dimensional ideal @xmath0 in a polynomial ring , many computations start by finding univariate polynomials in @xmath0 . searching for a univariate polynomial in @xmath0 is a particular case of considering the minimal polynomial of an element in @xmath1 . it is well known that minimal polynomials may be computed via elimination , therefore this is considered to be a `` resolved problem '' . but being the key of so many computations , it is worth investigating its meaning , its optimization , its applications . minimal polynomial . And you have already written the first three sentences of the full article: in linear algebra it is frequently necessary to use non - linear objects such as minimal and characteristic polynomials since they encode fundamental information about endomorphisms of finite - dimensional vector spaces . it is well - known that if @xmath2 is a field and @xmath3 is a zero - dimensional affine @xmath2-algebra , _ i.e. _ a zero - dimensional algebra of type @xmath4/i$ ] , then @xmath3 is a finite - dimensional @xmath2-vector space ( see proposition 3.7.1 of @xcite ) .. Please generate the next two sentences of the article

consequently , it not surprising that minimal and characteristic polynomials can be successfully used to detect properties of @xmath3 . this point of view was taken systematically in the new book @xcite where the particular importance of minimal polynomials ( rather greater than that of characteristic polynomials ) emerged quite clearly .

Suppose that you have an abstract for a scientific paper: we present a statistical method for the photometric search of rare astronomical sources based on the weighted @xmath0-nn method . a metric is defined in a multi - dimensional color - magnitude space based only on the photometric properties of template sources and the photometric uncertainties of both templates and data , without the need to define ad - hoc color and magnitude cuts which could bias the search . the metric is defined as a function of two parameters , the number of neighbors @xmath0 and a threshold distance @xmath1 that can be optimized for maximum selection efficiency and completeness . we apply the method to the search of l and t dwarfs in the _ spitzer _ extragalactic first look survey and the botes field of the _ spitzer _ shallow survey , as well as to the search of sub - stellar mass companions around nearby stars . with high level of completeness , we confirm the absence of late - t dwarfs detected in at least two bands in the first look survey , and only one in the shallow survey ( previously discovered by @xcite ) . this result is in agreement with the expected statistics for late - t dwarfs . one l / early - t candidate is found in the first look survey , and 3 in the shallow surveys , currently undergoing follow - up spectroscopic verification . finally , we discuss the potential for brown dwarf searches with this method in the _ spitzer _ warm mission exploration science programs . . And you have already written the first three sentences of the full article: one of the most common problems in astrophysics is the classification of astronomical sources based on their colors and magnitudes in a given photometric system . when high spectral resolution data ( or a large number of photometric bands covering the source sed ) are available , this classification , and the extraction of the physical parameters of the source , is generally achieved by fitting the observations with an appropriate physical model . in many instances , however , either a reliable model is not available , or the number of photometric bands is not sufficient to provide a robust source classification . when data fitting is not possible , a common fallback solution is to infer the nature of the sources to be classified by their proximity to `` regions '' in meaningful color - color and color - magnitude diagrams , where the sources of a certain class are expected to be found . these regions are in turn defined on the basis of generic physical considerations ( e.g. stars burning h in their cores are located on the region of the herzsprung - russell diagram we call main sequence ) or by association with other sources of the same class .. Please generate the next two sentences of the article

a typical example of this approach in the early years of infrared space astronomy were the iras color - color diagrams @xcite aimed to automatically classify the @xmath2 sources found by the infrared astronomical satellite in its bands at 12 , 25 , 60 and 100 . the diagrams were created by deriving the iras colors of @xmath3 sources whose nature could be inferred by the properties of their iras low resolution spectra @xcite .

Suppose that you have an abstract for a scientific paper: the fraction of ionizing photons ( @xmath0 ) that escape from @xmath1 galaxies is an important parameter when assessing the role of these objects in the reionization of the universe , but the opacity of the intergalactic medium precludes a direct measurement of @xmath0 for individual galaxies at these epochs . we argue , that since @xmath0 regulates the impact of nebular emission on the spectra of galaxies , it should nonetheless be possible to indirectly probe @xmath0 well into the reionization epoch . as a first step , we demonstrate that by combining measurements of the rest - frame uv slope @xmath2 with the equivalent width of the @xmath3 emission line , galaxies with very high lyman continuum escape fractions ( @xmath4 ) should be identifiable up to @xmath5 through spectroscopy with the upcoming james webb space telescope ( jwst ) . by targeting strongly lensed galaxies behind low - redshift galaxy clusters , jwst spectra of sufficiently good quality can be obtained for @xmath6 galaxies at @xmath7 and for @xmath8 galaxies at @xmath5 . dust - obscured star formation may complicate the analysis , but supporting observations with alma or the planned spica mission may provide useful constraints on the dust properties of these galaxies . . And you have already written the first three sentences of the full article: the spectra of high - redshift quasars suggest that cosmic reionization was completed by @xmath9 @xcite , and recent measurements of the kinetic sunyaev - zeldovich effect constrain the duration of this process to @xmath10 @xcite . the galaxy population at @xmath1 may in principle be sufficient to reionize the universe ( e.g. * ? ? ? * ; * ? ? ?. Please generate the next two sentences of the article

* ; * ? ? ? * ; * ? ? ?

Suppose that you have an abstract for a scientific paper: outflows in the form of fast winds from the accretion disk appear in nearly all high accretion rate cataclysmic variables ( cvs ) , both novalikes ( nls ) and dwarf novae in outburst ( dn ) . the primary signatures of cv winds are broad , blueshifted absorption features and p cygni profiles that appear in the ionized metal lines of lower inclination systems and the broad emission lines that appear in eclipsing systems . much progress has been made in our understanding of the structure and behavior of cv outflows based on data obtained with x - ray , euv , and uv telescopes and the kinematical models developed to fit the observations . our current picture of cv outflows is that they are bipolar , rotating winds driven off the accretion disk primarily by radiative line driving from disk , boundary layer , and white dwarf radiation . other mechanical forces may play a role in the formation of cv winds . the winds are highly turbulent and show complex vertical and azimuthal structure . future work will focus on determining the physical , thermal and ionization structure of the winds and probing the mechanisms that govern wind formation and behavior . . And you have already written the first three sentences of the full article: the study of outflows in cataclysmic variables ( cvs ) was born in the iue era . iue ultraviolet spectra of luminous cvs novalikes ( nls ) and dwarf novae ( dn ) in outburst showed high ionization uv transitions , particularly of civ @xmath01548,1552 , siiv @xmath01393,1402 and nv @xmath01238,1242 , appearing with very broad , blueshifted absorption components and p cygni profiles , shifting to pure emission in high orbital inclination systems @xcite . examples of wind - dominated fuv spectra of cvs at different inclinations are given in figure 1 , which shows observations taken from the far ultraviolet spectroscopic explorer ( fuse ) data archive .. Please generate the next two sentences of the article

it was immediately noted that the line profiles were similar to those seen in early - type and luminous stars such as o stars and wolf - rayet stars , in which the lines were ( and are ) believed to originate in expanding winds driven by radiation pressure @xcite . as a result , a wind origin for the uv lines of high accretion rate cvs was adopted early on .

Suppose that you have an abstract for a scientific paper: a reply to the above mentioned commentary by m.m . block and f. halzen on our quoted work is presented . we answer to each point raised by these authors and argument that our data reductions , strategies and methodology are adequate to the nonlinear - fit - problem in focus . in order to exemplify some arguments , additional information from our subsequent analysis is referred to . a brief commentary on the recent results by block and halzen is also presented . we understand that this reply gives support to the results and conclusions presented in our quoted work . pacs : 13.85.-t hadron - induced high- and super - high - energy interactions , 13.85.lg total cross sections , 11.10.jj asymptotic problems and properties * table of contents * i. introduction \ii . reply to the criticisms ii.a on the @xmath0 information ii.b statistical probabilities ii.c prediction of the 7 tev total @xmath1 cross section \iii . discussion iii.a on the fms analysis and results iii.b brief commentary on bh analysis and results \iv . conclusions and final remarks . And you have already written the first three sentences of the full article: in a recent communication m.m . block and f. halzen @xcite ( hereafter referred to as bh ) have presented some critical comments on our analysis @xcite ( hereafter fms ) . some points raised by these authors have already been addressed and discussed in our subsequent work @xcite ( hereafter fms2 ) , available as arxiv since august 16 , 2012 . in this note we reply to the bh criticisms directed to fms , recalling also some aspects of interest presented in fms2 . first , to facilitate the discussion and the reference to each part of the bh commentaries , some explanations on the organization of this reply are in order . excluding the acknowledgments and references , bh arxiv comprises four pages and the effective criticisms to fms. Please generate the next two sentences of the article

correspond to approximately one page . all the rest of the manuscript ( three pages ) largely overlap with their previous work @xcite ( as advised in the arxiv admin note " @xcite ) .

Suppose that you have an abstract for a scientific paper: this study proposes @xmath0-th tobit quantile regression models with endogenous variables . in the first stage regression of the endogenous variable on the exogenous variables , the assumption that the @xmath1-th quantile of the error term is zero is introduced . then , the residual of this regression model is included in the @xmath0-th quantile regression model in such a way that the @xmath0-th conditional quantile of the new error term is zero . the error distribution of the first stage regression is modelled around the zero @xmath1-th quantile assumption by using parametric and semiparametric approaches . since the value of @xmath1 is a priori unknown , it is treated as an additional parameter and is estimated from the data . the proposed models are then demonstrated by using simulated data and real data on the labour supply of married women . * keywords * : asymmetric laplace distribution ; bayesian tobit quantile regression ; dirichlet process mixture ; endogenous variable ; markov chain monte carlo ; skew normal distribution ; . And you have already written the first three sentences of the full article: since the seminal work of koenker and bassett ( 1978 ) , quantile regression has received substantial scholarly attention as an important alternative to conventional mean regression . indeed , there now exists a large literature on the theory of quantile regression ( see , for example , koenker ( 2005 ) , yu _ et al_. ( 2003 ) , and buchinsky ( 1998 ) for an overview ) . notably , quantile regression can be used to analyse the relationship between the conditional quantiles of the response distribution and a set of regressors , while conventional mean regression only examines the relationship between the conditional mean of the response distribution and the regressors . quantile regression can thus be used to analyse data that include censored responses .. Please generate the next two sentences of the article

powell ( 1984 ; 1986 ) proposed a tobit quantile regression ( tqr ) model utilising the equivariance of quantiles under monotone transformations . hahn ( 1995 ) , buchinsky and hahn ( 1998 ) , bilias _ et al_. ( 2000 ) , chernozhukov and hong ( 2002 ) , and tang _ et al_. ( 2012 ) considered alternative approaches to estimate tqr .

Suppose that you have an abstract for a scientific paper: the planetary exospheres are poorly known in their outer parts , since the neutral densities are low compared with the instruments detection capabilities . the exospheric models are thus often the main source of information at such high altitudes . we present a new way to take into account analytically the additional effect of the radiation pressure on planetary exospheres . in a series of papers , we present with an hamiltonian approach the effect of the radiation pressure on dynamical trajectories , density profiles and escaping thermal flux . our work is a generalization of the study by @xcite . in this first paper , we present the complete exact solutions of particles trajectories , which are not conics , under the influence of the solar radiation pressure . this problem was recently partly solved by @xcite and completely by @xcite . we give here the full set of solutions , including solutions not previously derived , as well as simpler formulations for previously known cases and comparisons with recent works . the solutions given may also be applied to the classical stark problem @xcite : we thus provide here for the first time the complete set of solutions for this well - known effect in term of jacobi elliptic functions . exosphere , radiation pressure , stark effect , trajectories . And you have already written the first three sentences of the full article: the exosphere is the upper layer of any planetary atmosphere : it is a quasi - collisionless medium where the particle trajectories are more dominated by gravity than by collisions . above the exobase , the lower limit of the exosphere , the knudsen number @xcite becomes large , collisions become scarce , the distribution function can not be considered as maxwellian anymore and , gradually , the trajectories of particles are essentially determined by the gravitation and radiation pressure by the sun . the trajectories of particles , subject to the gravitational force , are completely solved with the equations of motion , but it is not the case with the radiation pressure @xcite . in the absence of radiation pressure , we can distinguish three types of trajectories for the exospheric particles : * the escaping particles come from the exobase and have a positive mechanical energy : they can escape from the gravitational influence of the planet with a velocity larger than the escape velocity .. Please generate the next two sentences of the article

these particles are responsible for the jeans escape @xcite . they can also be defined as crossing only once the exobase , * the ballistic particles also come from the exobase but have a negative mechanical energy , they are gravitationally bound to the planet .

Suppose that you have an abstract for a scientific paper: the quantum susy n=1 hierarchy based on @xmath0 twisted affine superalgebra is considered . the construction of the corresponding baxter s q - operators and fusion relations is outlined . the relation with the superconformal field theory is discussed . one of the most famous integrable systems ( is ) is the korteweg - de vries hierarchy . it is related with the superconformal field theory because its poisson brackets give the virasoro algebra and the involutive family of integrals of motion ( i m ) providing the integrability of the conformal field theory ( cft ) . since the late 1980s the supersymmetric and fermionic extensions of the kdv system have been known ( see e.g. @xcite , @xcite , @xcite and references therein ) , which in turn are related with superconformal field theory ( scft ) . during the following years they were extensively studied on both the classical and the quantum level . + however , up to the present nobody has applied the most successful method in the theory of integrable systems , the so - called quantum inverse scattering method ( qism ) to these is . in this short paper we demonstrate some algebraic tools giving possibility to study susy n=1 kdv via qism . . And you have already written the first three sentences of the full article: the susy n=1 kdv model is related to the following l - operator : @xmath1 where @xmath2 , @xmath3 , @xmath4 are the chevalley generators of twisted affine lie superalgebra @xmath5 , @xmath6 is a superderivative , the variable @xmath7 lies on a cylinder of circumference @xmath8 , @xmath9 is a grassmann variable , @xmath10 is a bosonic superfield with the following poisson brackets : @xmath11 . making a gauge transformation of the l - operator we obtain a new superfield @xmath12 = @xmath13 , where @xmath14 and @xmath15 generate the superconformal algebra under the poisson brackets : @xmath16 the susy n=1 kdv system has an infinite number of conservation laws and the first nontrivial one gives the susy n=1 kdv equation : @xmath17 the integrals of motion are generated by the logarithm of the supertrace of the corresponding monodromy matrix , which has the following form : @xmath18 @xmath19 \big).\ ] ] its quantum generalization can be represented in the quantum p - exponential form ( for the explanation of this notion see below and @xcite for details ) : @xmath20 vertex operators @xmath21 are defined in the following way @xmath22 . the universal r - matrix with the lower borel subalgebra represented by @xmath23 is equal to @xmath24 . due to this fact @xmath25 satisfies the rtt - relation : @xmath26 where @xmath27 , @xmath28 mean that the corresponding object is considered in some representation of @xmath29 .. Please generate the next two sentences of the article

thus the supertraces of the monodromy matrix ( `` transfer matrices '' ) @xmath30 commute , providing the quantum integrability . it is very useful to consider the evaluation representations of @xmath29 , @xmath31 , where now the symbol @xmath27 means integer and half - integer numbers . denoting @xmath32 as @xmath33

Suppose that you have an abstract for a scientific paper: the problem of two magnetic impurities in a normal metal exposes the two opposite tendencies in the formation of a singlet ground state , driven respectively by the single - ion kondo effect with conduction electrons to screen impurity spins or the ruderman - kittel - kasuya - yosida interaction between the two impurities to directly form impurity spin singlet . however , whether the competition between these two tendencies can lead to a quantum critical point has been debated over more than two decades . here , we study this problem by applying the newly proposed natural orbitals renormalization group method to a lattice version of the two - impurity kondo model with a direct exchange @xmath0 between the two impurity spins . the method allows for unbiased accessing the ground state wave functions and low - lying excitations for sufficiently large system sizes . we demonstrate the existence of a quantum critical point , characterized by the power - law divergence of impurity staggered susceptibility with critical exponent @xmath1 , on the antiferromagnetic side of @xmath0 when the interimpurity distance @xmath2 is even lattice spacing , while a crossover behavior is recovered when @xmath2 is odd lattice spacing . these results have ultimately resolved the long - standing discrepancy between the numerical renormalization group and quantum monte carlo studies , confirming a link of this two - impurity kondo critical point to a hidden particle - hole symmetry predicted by the local fermi liquid theory . . And you have already written the first three sentences of the full article: it is well - recognized that the competition between the single - ion kondo effect and the ruderman - kittel - kasuya - yosida ( rkky ) interaction , the two inevitable forces in any kondo systems with more than one local impurity magnetic moment , plays a crucial role in correlated systems ranging from dilute magnetic alloys to heavy fermion compounds @xcite . the indirect rkky interaction , namely the interimpurity interaction mediated by conduction electrons via a short - range ( on - site ) kondo coupling , oscillates and decays with the interimpurity distance @xmath2 and fermi momentum @xmath3 @xcite . when the rkky interaction grows toward the strong antiferromagnetic limit , the quantum many - body ground state will evolve from a collective kondo singlet state@xcite into the interimpurity singlet state locked by the rkky interaction .. Please generate the next two sentences of the article

however , whether a distinct separation or a quantum critical point exists between the two singlet ground states has remained elusive . this theoretical issue has a fundamental importance as it closely correlates with the critical divergence or scaling behavior of several physical quantities , or emergent energy scales in realistic materials@xcite .

Suppose that you have an abstract for a scientific paper: we investigate the electron transport in multiply connected metallic carbon nanotubes within the landauer - bttiker formalism . quasibound states coupled to the incident @xmath0 states give rise to energy levels of different widths depending on the coupling strength . in particular , donorlike states originating from heptagonal rings are found to give a very narrow level . interference between broad and narrow levels produces fano - type resonant backscattering as well as resonant tunneling . over a significantly wide energy range , almost perfect suppression of the conduction of @xmath0 electrons occurs , which may be regarded as filtering of particular electrons ( @xmath1-pass filter ) . . And you have already written the first three sentences of the full article: in the past decade , carbon nanotubes ( cnts ) have been studied extensively because of their unconventional properties from both the fundamental research and application point of view @xcite . for the application to nanoscale electronic devices , researchers have fabricated various forms of cnts to engineer their physical properties . @xmath2-bonded carbon nanostructures have been found to coalesce by electron beam irradiation at high temperature and new morphologies such as x- and t - shaped junctions have been produced @xcite .. Please generate the next two sentences of the article

these developments offer interesting opportunities to study phase - coherent transport in novel geometries . thus far , phase - coherent transport has been most actively studied in the semiconductor heterostructures by employing the aharonov - bohm ( ab ) interferometer @xcite with an embedded quantum dot in one arm .

Suppose that you have an abstract for a scientific paper: wide - band radio polarization observations offer the possibility to recover information about the magnetic fields in synchrotron sources , such as details of their three - dimensional configuration , that has previously been inaccessible . the key physical process involved is the faraday rotation of the polarized emission in the source ( and elsewhere along the wave s propagation path to the observer ) . in order to proceed , reliable methods are required for inverting the signals observed in wavelength space into useful data in faraday space , with robust estimates of their uncertainty . in this paper , we examine how variations of the intrinsic angle of polarized emission @xmath0 with the faraday depth @xmath1 within a source affect the observable quantities . using simple models for the faraday dispersion @xmath2 and @xmath3 , along with the current and planned properties of the main radio interferometers , we demonstrate how degeneracies among the parameters describing the magneto - ionic medium can be minimised by combining observations in different wavebands . we also discuss how depolarization by faraday dispersion due to a random component of the magnetic field attenuates the variations in the spectral energy distribution of the polarization and shifts its peak towards shorter wavelengths . this additional effect reduces the prospect of recovering the characteristics of the magnetic field helicity in magneto - ionic media dominated by the turbulent component of the magnetic field . [ firstpage ] polarization methods : data analysis techniques : polarimetric ism : magnetic fields galaxies : magnetic fields radio continuum : galaxies . And you have already written the first three sentences of the full article: a new generation of radio telescopes will map the polarization of cosmic radio sources over a large range of wavelengths , from a few centimetres to several metres . since the plane of polarization of a linearly polarized wave is rotated by an amount that depends on the magnetic field and free - electron distributions and the wavelength ( @xmath4 ) , the resulting data will probe both the synchrotron - emitting sources and any intervening magneto - ionic medium in unprecedented detail . a useful way to characterize the intrinsic properties of magneto - ionic media is the faraday dispersion function , @xmath2 , which contains information on the transverse orientation of the magnetic field ( @xmath5 ) and on the intrinsic polarized emission as a function of faraday depth , @xmath1 .. Please generate the next two sentences of the article

the faraday depth is proportional to the integral along the line of sight @xmath6 of the product of the density of thermal electrons , @xmath7 , and the component of the magnetic field parallel to the line of sight : @xmath8 hence , in principle , @xmath2 can be used to obtain both the perpendicular and the parallel components of the three - dimensional magnetic field . ( our system of coordinates is such that the origin is at the far end of the source and the observer is located at @xmath9 .

Suppose that you have an abstract for a scientific paper: we report experiments on defect - tracking in the state of undulation chaos observed in thermal convection of an inclined fluid layer . we characterize the ensemble of defect trajectories according to their velocities , relative positions , diffusion , and gain and loss rates . in particular , the defects exhibit incidents of rapid transverse motion which result in power law distributions for a number of quantitative measures . we examine connections between this behavior and lvy flights and anomalous diffusion . in addition , we describe time - reversal and system size invariance for defect creation and annihilation rates . * pacs : * 47.54.+r , 47.20.bp * keywords : * pattern formation , convection , defect turbulence , anomalous diffusion , lvy flights * topological defects within patterns are observed in many systems to move in a spatiotemporally chaotic fashion . we examine the motion of such defects within a defect - turbulent state observed in thermal convection of an inclined fluid layer . we characterize the trajectories of the defects both by analogy to fluid turbulence velocity distributions , diffusion , and power spectra and by properties dependent upon the topological characteristics of the defects : pair creation / annihilation and interactions . * ' '' '' . And you have already written the first three sentences of the full article: nonequilibrium systems with similar symmetries often form patterns which appear to be universal in spite of having been formed by different physical mechanisms @xcite . in particular , reduced descriptions of the patterns often quantify the similarities in behavior so that understanding of one system can lead to insights in multiple systems . a class of spatiotemporally chaotic states exhibiting defect - mediated turbulence @xcite has been found in such diverse systems as wind - driven sand , electroconvection in liquid crystals @xcite , nonlinear optics @xcite , fluid convection @xcite , and autocatalytic chemical reactions @xcite . in many cases , such systems have been modeled via the complex ginzburg - landau equation @xcite . these various defect turbulent patterns are characterized by an underlying striped state which contains dislocations ( point defects ) where the stripes dead - end within the pattern . locally , the defects distort the orientation and wavenumber of the stripes and the nucleation , motion , and annihilation of the defects constitute a spatiotemporally chaotic system .. Please generate the next two sentences of the article

an example from inclined layer convection is shown in fig . [ d_f_pic ] .

Suppose that you have an abstract for a scientific paper: we mapped @xmath0co and @xmath1co j = @xmath2 emission over 1.04 deg@xmath3 of the serpens molecular cloud with @xmath4 spatial and 0.3 km s@xmath5 spectral resolution using the arizona radio observatory heinrich hertz submillimeter telescope . our maps resolve kinematic properties for the entire serpens cloud . we also compare our velocity moment maps with known positions of young stellar objects ( ysos ) and 1.1 mm continuum emission . we find that @xmath0co is self - absorbed and @xmath1co is optically thick in the serpens core . outside of the serpens core , gas appears in filamentary structures having lsr velocities which are blue - shifted by up to 2 km s@xmath5 relative to the 8 km s@xmath5 systemic velocity of the serpens cloud . we show that the known class i , flat , and class ii ysos in the serpens core most likely formed at the same spatial location and have since drifted apart . the spatial and velocity structure of the @xmath0co line ratios implies that a detailed 3-dimensional radiative transfer model of the cloud will be necessary for full interpretation of our spectral data . the starless cores " region of the cloud is likely to be the next site of star formation in serpens . . And you have already written the first three sentences of the full article: the serpens cloud is a low mass star - forming cloud in the gould belt . the cloud is known for its high star formation rate ( sfr ) and high surface density of young stellar objects ( ysos ) ( eiroa et al . a 10 deg@xmath3 optical extinction ( a@xmath6 ) map made by cambresy ( 1999 ) originally defined the serpens cloud .. Please generate the next two sentences of the article

more recent studies treat the serpens cloud as two much smaller ( @xmath7 1.0 deg@xmath8 ) regions : serpens main ( centered on r.a . @xmath9 , dec . @xmath10 ( j2000 ) ) and serpens south ( centered on r.a .

Suppose that you have an abstract for a scientific paper: this study reports pulse variation analysis results for the forth discovered accretion - powered millisecond pulsar xte j1807 - 294 during its 2003 outburst observed by _ rossi x - ray timing explorer_. the pulsation is significantly detected only in the first @xmath090d out of @xmath0150d observations . the pulse phase variation is too complex to be described as an orbital motion plus a simple polynomial model . the precise orbital parameters with @xmath1 min and @xmath2 lt - ms were obtained after applying the trend removal to the daily observed 150s segments pulse phases folded with a constant spin frequency without keplerian orbit included . the binary barycenter corrected pulse phases show smooth evolution and clear negative phase shifts coincident with the flares seen on the light curve and the enhancements of fractional pulse amplitude . the non - flare pulse phases for the first @xmath060d data are well described as a fourth order polynomial implying that the neutron star was spun - up during the first @xmath060d with a rate @xmath3 hz / s at the beginning of the outburst . significant soft phase lags up to @xmath0500 @xmath4 ( @xmath010% cycle ) between 2 to 20 kev were detected for the nonflare pulse phases . we conclude that the anomalous phase shifts are unlikely due to the accretion torque but could result from the `` hot spot '' moving on the surface of neutron star . . And you have already written the first three sentences of the full article: low mass x - ray binaries ( lmxbs ) are considered to be the progenitor of the millisecond pulsars detected in the radio band ( see @xcite for an extensive review ) . it is widely believed that the weakly magnetized , slowly rotating neutron star is gradually spun - up through the transfer of angular momentum carried by the matter from an accretion disk @xcite . millisecond - time - scale variations have been observed in many lmxb systems , including kilohertz quasi - periodic oscillation ( khz qpo , see * ? ? ?. Please generate the next two sentences of the article

* ) and burst oscillation ( see @xcite for a review ) ; however , the attempts to measure coherent millisecond pulsation from an lmxb , which provides a direct evolutionary link between radio millisecond pulsar and lmxb , were unsuccessful until the discovery of the first accretion - powered millisecond pulsar sax 1808.4 - 3658 with a spin period @xmath5 ms @xcite , in 1998 . to date , coherent millisecond pulsations have been detected in ten lmxbs with spin periods ranging from 1.67 ms to 5.5 ms @xcite .

Suppose that you have an abstract for a scientific paper: we study the radiative symmetry breaking of @xmath0 in supersymmetric models with inverse seesaw mechanism . we show that for a wide region of parameter space the radiative corrections can drive the squared mass of the extra higgs boson from positive initial values at the gut scale to negative values at the tev scale , leading to the spontaneous breaking of the @xmath0 symmetry . we also emphasize that in this class of models , unlike the supersymmetric @xmath0 models with type i seesaw , the right - handed sneutrino can not get a non - zero vacuum expectation value . therefore , @xmath0 can be radiatively broken while @xmath1-parity remains an exact symmetry . . And you have already written the first three sentences of the full article: the minimal @xmath0 extension of the standard model ( sm ) , which is based on the gauge group @xmath2 , provides a satisfactory explanation for the non - zero neutrino masses @xcite . in this class of models , sm singlet fermions are naturally introduced in order to cancel the associated anomaly . these particles are accounted for right - handed neutrinos and hence a seesaw mechanism can be obtained .. Please generate the next two sentences of the article

it was shown that light neutrino masses can be generated within @xmath0 extension of the sm through either type - i seesaw @xcite or inverse seesaw mechanism @xcite . in type - i seesaw mechanism right - handed neutrinos acquire majorana masses at the @xmath0 symmetry breaking scale , therefore the neutrino s yukawa coupling must be @xmath3 , while in inverse seesaw these majorana masses are not allowed by the @xmath0 gauge symmetry and another pair of sm gauge singlet fermions with tiny masses @xmath4 kev must be introduced .

Suppose that you have an abstract for a scientific paper: we experimentally show that the non - separability of polarization and orbital angular momentum present in a light beam remains preserved under scattering through a random medium like rotating ground glass . we verify this by measuring the degree of polarization and observing the intensity distribution of the beam when projected to different polarization states , before as well as after the scattering . we extend our study to the non - maximally non - separable states also . non - separability , orbital angular momentum , scattering , linear entropy . And you have already written the first three sentences of the full article: a combined system is said to be entangled when its state can not be expressed as a product of states corresponding to the individual sub systems @xcite . the entangled systems have interesting properties such as non - locality and contextuality which make them a great resource for various quantum protocols @xcite . one generally uses the entanglement between two spatially separated particles in the same degree of freedom such as spin or polarization .. Please generate the next two sentences of the article

however , one can also have hybrid entanglement in which two degrees of freedom of a single particle or two particles are entangled @xcite . this arises due to the non - separability of two degrees of freedom .

Suppose that you have an abstract for a scientific paper: we have synthesized polycrystalline and single crystal samples of pbcu@xmath0teo@xmath1 and studied its properties via magnetic susceptibility @xmath2 and heat - capacity @xmath3 measurements and also electronic structure calculations . whereas the crystal structure is suggestive of the presence of a quasi-@xmath4 network of cu@xmath5 @xmath6 buckled staircase kagome layers , the @xmath2 data show magnetic anisotropy and three magnetic anomalies at temperatures , @xmath7 k , @xmath8 k , @xmath9 k , respectively . the @xmath2 data follow the curie - weiss law above @xmath10 k and a curie - weiss temperature @xmath11 k is obtained . the data deviate from the simple curie - weiss law below @xmath10 k , which is well above @xmath12 , suggesting the presence of competing magnetic interactions . the magnetic anomaly at @xmath13 appears to be of first - order from magnetization measurements , although our heat - capacity @xmath3 results do not display any anomaly at @xmath14 the hopping integrals obtained from our electronic structure calculations suggest the presence of significant intra - kagome ( next - nearest neighbor and diagonal ) and inter - kagome couplings . these couplings take the pbcu@xmath0teo@xmath1 system away from a disordered ground state and lead to long - range order , in contrast to what might be expected for an ideal ( isotropic ) @xmath4 kagome system . . And you have already written the first three sentences of the full article: frustrated magnetism in kagome heisenberg antiferromagnetic systems ( khaf ) has been a major subject in condensed matter physics due to their unconventional , exotic ground states which emerge from the interplay between geometrical frustration and low - dimensional quantum effects.gfm2005,gfm2011 in particular , quantum fluctuations for @xmath15 systems are found to be strong among khaf and can lead to interesting behavior like that of a spin liquid.@xcite theoretical studies on ideal @xmath15 isotropic khaf lattice have demonstrated that it has a resonating valence bond ( rvb)-like disordered ground state.@xcite recent numerical studies @xcite have also predicted that its ground state is a spin liquid with a small spin - gap ( @xmath16 ) of @xmath17 to its triplet excited state ( where @xmath18 is the exchange interaction between nearest - neighbor ( @xmath19 ) spins ) . a limited number of experimental realizations of structurally ideal , @xmath20 khaf have been found , which include zn and mg - herberthsmithite , kapellasite , and haydeeite.lists=1/2kagome,e . fak 2012 among these , zn - herberthsmithite zncu@xmath0(oh)@xmath21cl@xmath22 is the best example to explain isotropic @xmath15 khaf behavior .. Please generate the next two sentences of the article

experimental studies on zn - herberthsmithite have shown that there is no magnetic ordering down to @xmath23 k , which implies that it has a disordered ground state.@xcite but an unambiguous proof for the existence of a spin - gap from an experimental point of view is lacking . the natural ion exchange of cu and zn or mg is inevitable in these systems , which is probably the main obstacle to detect the intrinsic nature of these @xmath15 khaf .

Suppose that you have an abstract for a scientific paper: based on a renormalization - group picture of @xmath0 symmetric models in three dimensions , we derive a scaling law for the @xmath0 order parameter in the ordered phase . an existing monte carlo calculation on the three - state antiferromagnetic potts model , which has the effective @xmath1 symmetry , is shown to be consistent with the proposed scaling law . it strongly supports the renormalization - group picture that there is a single massive ordered phase , although an apparently rotationally symmetric region in the intermediate temperature was observed numerically . . And you have already written the first three sentences of the full article: the symmetry and the dimensionality are important factors to determine the universality class of critical phenomena . the @xmath2 symmetry is the simplest among the continuous symmetry , and statistical models with the @xmath2 symmetry has been studied intensively . a natural question then would be the effect of the symmetry breaking from the continuous @xmath2 to the discrete @xmath0 .. Please generate the next two sentences of the article

a simple spin model with @xmath0 symmetry is the @xmath3-state clock model with a hamiltonian @xmath4 where @xmath5 runs over nearest neighbors , and @xmath6 takes integral multiples of @xmath7 . the standard xy model with @xmath2 symmetry is defined by the hamiltonian of the same form ; the only difference is that @xmath8 takes continuous values .

Suppose that you have an abstract for a scientific paper: the palomar integral field spectrograph was used to probe a variety of environments in nine nearby galaxies that span a range of morphological types , luminosities , metallicities , and infrared - to - blue ratios . for the first time , near - infrared spectroscopy was obtained for nuclear or bright regions in star - forming galaxies over two spatial dimensions ( 57 @xmath0 100 ) in the ( 1.257 ) , ( 1.644 ) , ( 1.282 ) , ( 2.122 ) , and ( 2.166 ) transition lines . these data yield constraints on various characteristics of the star - forming episodes in these regions , including their strength , maturity , spatial variability , and extinction . the regions stand out from the nuclei . unlike observations of nuclear regions , region near - infrared observations do not show a spatial coincidence of the line and continuum emission ; the continuum and line maps of regions usually show distinct and sometimes spatially - separated morphologies . gauging from and equivalent widths and luminosities , the regions have younger episodes of star formation than the nuclei and more intense radiation fields . near - infrared line ratio diagnostics suggest that regions have `` purer '' starbursting properties . the correlation between ionizing photon density and mid - infrared color is consistent with the star formation activity level being higher for regions than for nuclei . and though the interpretation is complicated , on a purely empirical basis the regions show lower fe@xmath1 abundances than nuclei by an order of magnitude . . And you have already written the first three sentences of the full article: stellar processing is the main evolutionary process affecting the cosmos . nucleosynthesis and mass return to the interstellar medium modify the chemical composition of the universe and the fraction of mass bound in stars . star formation dominates the present - day radiation field , and most of it happens in normal galaxies ( e.g. kim & sanders 1998 ; driver 1999 ) .. Please generate the next two sentences of the article

relatively little , however , is known about star formation on the scale of a galaxy , including its drivers and inhibitors , and the role of interactions ( e.g. volker 2000 ; dopita et al . 2002 ; hameed & young 2003 ) . the @xmath2 key project on the interstellar medium of normal galaxies ( helou et al .

Suppose that you have an abstract for a scientific paper: the signature function of a knot is a locally constant integer valued function with domain the unit circle . the jumps ( i.e. , the discontinuities ) of the signature function can occur only at the roots of the alexander polynomial on the unit circle . the latter are important in deforming @xmath0 representations of knot groups to irreducible @xmath1 representations . under the assumption that these roots are simple , we formulate a conjecture that explicitly computes the jumps of the signature function in terms of the jones polynomial of a knot and its parallels . as evidence , we prove our conjecture for torus knots , and also ( using computer calculations ) for knots with at most @xmath2 crossings . we also give a formula for the jump function at simple roots in terms of relative signs of alexander polynomials . . And you have already written the first three sentences of the full article: a celebrated invariant of a knot @xmath3 in 3-space is its _ function _ @xmath4 defined for complex numbers of absolute value @xmath5 , and taking values in the set of integers . the signature function of a knot is a concordance invariant , and plays a key role in the study of knots via surgery theory , @xcite .. Please generate the next two sentences of the article

it turns out that the signature function is a locally constant function away from the ( possibly empty ) set @xmath6 of roots of the alexander polynomial on the unit circle . in view of this , the interesting part of the signature function is its _ jumping behavior _ on the set @xmath7 . in other words , we may consider the associated _ jump function _

Suppose that you have an abstract for a scientific paper: we study the low - temperature phase of the three - dimensional @xmath0 ising spin glass in migdal - kadanoff approximation . at zero temperature , @xmath1 , the properties of the spin glass result from the ground - state degeneracy and can be elucidated using scaling arguments based on entropy . the approach to the asymptotic scaling regime is very slow , and the correct exponents are only visible beyond system sizes around 64 . at @xmath2 , a crossover from the zero - temperature behaviour to the behaviour expected from the droplet picture occurs at length scales proportional to @xmath3 where @xmath4 is the fractal dimension of a domain wall . canonical droplet behaviour is not visible at any temperature for systems whose linear dimension is smaller than 16 lattice spacings , because the data are either affected by the zero - temperature behaviour or the critical point behaviour . 2 . And you have already written the first three sentences of the full article: there is still no agreement about the nature of the low - temperature phase of the ising spin glass , which is defined by the hamiltonian @xmath5 the spins can take the values @xmath6 , and the nearest - neighbour couplings @xmath7 are independent from each other and are most often chosen to be gaussian distributed with mean zero and a standard deviation @xmath8 . while many monte - carlo simulations show properties conforming to the replica - symmetry - breaking ( rsb ) scenario ( implying many low - temperature states and a lack of self - averaging ) @xcite , other simulations @xcite and analytical arguments @xcite favour the droplet picture ( a scaling theory based on the existence of only one low - temperature state and its time reverse ) . the ambiguities stem from the difficulty in reaching the asymptotic limit of low temperatures and large system sizes . monte - carlo results are likely to be affected by finite - size and critical - point effects .. Please generate the next two sentences of the article

we have recently shown that a system that is known to conform to the droplet picture at sufficiently large system sizes has features similar to those of rsb if only small systems are studied and if the temperature is not low enough @xcite . this system is the hierarchical lattice , or , equivalently , the migdal - kadanoff approximation ( mka ) applied to a cubic or hypercubic lattice .

Suppose that you have an abstract for a scientific paper: we consider the collective neutrino plasma interactions , and study the electron plasma instabilities produced by a nearly mono - energetic neutrino beam in a plasma . we describe the mutual influence of neutrino flavor oscillations and electron plasma waves . we show that the neutrino flavor oscillations are not only perturbed by electron plasmas waves , but also contribute to the dispersion relation and the growth rates of neutrino beam instabilities . . And you have already written the first three sentences of the full article: neutrino interactions with plasma are very important to understand supernova explosions and many other astrophysical phenomena @xcite . two types of effects arise from such interactions . first , they modify the neutrino flavor oscillations @xcite , and introduce a resonant coupling between different flavor states , known as the msw ( mikheyev - smirnov - wolfenstein ) effect @xcite .. Please generate the next two sentences of the article

second , they create an induced neutrino charge @xcite , which can lead to collective plasma oscillations and significantly increase the collision cross sections . the energy transfer between a neutrino beam and plasma wave is mediated by the neutrino landau damping @xcite .

Suppose that you have an abstract for a scientific paper: we discuss the issue of quasi - particle production by `` analogue black holes '' with particular attention to the possibility of reproducing hawking radiation in a laboratory . by constructing simple geometric acoustic models , we obtain a somewhat unexpected result : we show that in order to obtain a stationary and planckian emission of quasi - particles , it is _ not _ necessary to create an ergoregion in the acoustic spacetime ( corresponding to a supersonic regime in the flow ) . it is sufficient to set up a dynamically changing flow _ either _ eventually generating an arbitrarily small sonic region @xmath0 , but without any ergoregion , _ or _ even just asymptotically , in laboratory time , approaching a sonic regime with sufficient rapidity . pacs : 04.20.gz , 04.62.+v , 04.70.-s , 04.70.dy , 04.80.cc + keywords : analogue models , acoustic spacetime , hawking radiation . And you have already written the first three sentences of the full article: it is by now well established that the physics associated with classical and quantum fields in curved spacetimes can be reproduced , within certain approximations , in a variety of different physical systems the so - called `` analogue models of general relativity ( gr ) '' @xcite . the simplest example of such a system is provided by acoustic disturbances propagating in a barotropic , irrotational and viscosity - free fluid . in the context of analogue models it is natural to separate the kinematical aspects of gr from the dynamical ones . in general , within a sufficiently complex analogue model one can reproduce any pre - specified spacetime and the kinematics of fields evolving on it independently of whether or not it satisfies the classical ( or semiclassical ) einstein equations @xcite .. Please generate the next two sentences of the article

indeed , to date there are no analogue models whose effective geometry is determined by einstein equations . in this sense we currently have both analogue spacetimes and analogues of quantum field theory in curved spacetimes , but ( strictly speaking ) no analogue model for gr itself @xcite . in order to reproduce a specific spacetime geometry within an analogue model

Suppose that you have an abstract for a scientific paper: while the low frequency electronic raman response in the superconducting state of the cuprates can be largely understood in terms of a d - wave energy gap , a long standing problem has been an explanation for the spectra observed in @xmath0 polarization orientations . we present calculations which suggest that the peak position of the observed @xmath0 spectra is due to a collective spin fluctuation mode . . And you have already written the first three sentences of the full article: in spite of the considerable efforts to explain the experimental raman spectra of cuprate superconductors , the @xmath0 superconducting response is not yet completely understood . it has been shown that the theoretical description of the @xmath0 raman response was very sensitive to small changes in the raman vertex harmonic representations , yielding peak positions varying between @xmath1 and 2@xmath1 @xcite . however , the data show peaks consistently slightly above @xmath1 for both ybco and bscco . in this paper we present calculations suggesting that the @xmath0 peak position is largely controlled by a collective spin fluctuation ( sf ) mode near 41 mev , consistent with inelastic neutron scattering ( ins ) observations @xcite . we show that the @xmath0 response is strongly modified by the sf term and is not sensitive to small changes in the raman vertex . the experimental peak position is well reproduced by our model whereas the @xmath2 and @xmath3 response remain essentially unaffected by the sf mode .. Please generate the next two sentences of the article

the cuo@xmath4 bilayer is modeled by a tight binding band structure with a nearest ( @xmath5 ) and a next nearest neighbor hopping ( @xmath6 ) parameter and an inter - plane hopping given by @xcite @xmath7 ^ 2 .\ ] ] @xmath8 can be 0 or @xmath9 , for bonding or anti - bonding bands of the bilayer , respectively . the spin susceptibility ( @xmath10 ) is modeled by extending the weak coupling form of a @xmath11 superconductor to include antiferromagnetic spin fluctuations by an rpa form with an effective interaction @xmath12 ; i.e. @xmath13 where @xmath14 is the simple bubble in the d - wave state .

Suppose that you have an abstract for a scientific paper: we present results from numerical studies of supervised learning operations in recurrent networks considered as graphs , leading from a given set of input conditions to predetermined outputs . graphs that have optimized their output for particular inputs with respect to predetermined outputs are asymptotically stable and can be characterized by attractors which form a representation space for an associative multiplicative structure of input operations . as the mapping from a series of inputs onto a series of such attractors generally depends on the sequence of inputs , this structure is generally non - commutative . moreover , the size of the set of attractors , indicating the complexity of learning , is found to behave non - monotonically as learning proceeds . a tentative relation between this complexity and the notion of pragmatic information is indicated . . And you have already written the first three sentences of the full article: graph theory has recently reveived increasing attraction for applications to complex systems in various disciplines ( gernert 1997 , paton 2002a , b , bornholdt and schuster 2003 ) . the characterization of systems ( with interrelated constituents ) by graphs ( with linked vertices ) is comparably general as their characterization in terms of categories ( with elements related by morphisms ) . despite its generality , graph theory has turned out to be a powerful tool for gaining very specific insight into structural and dynamical properties of complex systems ( see jost and joy 2002 , atmanspacher et al .. Please generate the next two sentences of the article

2005 for examples ) . an area of particularly intense interest , in which complex systems abound , is biological information processing .

Suppose that you have an abstract for a scientific paper: the stellar populations in the bulges of s0s , together with the galaxies dynamics , masses and globular clusters , contain very interesting clues about their formation . i present here recent evidence suggesting that s0s are the descendants of fading spirals whose star formation ceased . lenticular , or s0 , galaxies make up some 25% of large galaxies in the local universe ( dressler 1980 ) , so understanding how they form must constitute a significant element of any explanation of galaxy evolution . their location at the crossroads between ellipticals and spirals in hubble s tuning - fork diagram underlines their importance in attempts to develop a unified understanding of galaxy evolution , but also means that it is not even clear to which of these classes of galaxy they are more closely related . one often - cited piece of evidence comes from the fact that the proportion of s0s is substantially smaller in distant ( @xmath0 ) clusters than in nearby ones , while spirals show the opposite trend ( dressler et al . 1997 ) , strongly suggesting a transformation from one to the other . however , even if this scenario is accepted , it does not answer the question as to whether s0s are more closely related to spirals or ellipticals , which is intimately connected to the mechanism of transformation . if the transformation simply involves a spiral galaxy losing its gas content through ram pressure stripping ( gunn & gott 1972 ) or `` strangulation '' ( larson et al . 1980 ) , so ceasing star formation and fading into an s0 , then clearly s0s and spirals are closely related . however , it is also possible that mergers can cause such a transformation : while equal - mass mergers between spirals create elliptical galaxies , more minor mergers can heat the original disk of a spiral and trigger a brief burst of star formation , using up the residual gas and leaving an s0 . in such a merger scenario , the mechanism for creating an s0 is much more closely related to that for the formation of.... And you have already written the first three sentences of the full article: combining published data with high - quality vlt / fors spectroscopy of sample of fornax s0s ( bedregal et al . 2006a ) we have carried out a combined study of the tully - fisher relation and the stellar populations of these galaxies . despite the relatively small sample and the considerable technical challenges involved in determining the true rotation velocity @xmath1 from absorption line spectra of galaxies with significant non - rotational support ( see mathieu et al . 2002 ) , some very interesting results arise .. Please generate the next two sentences of the article

s0s lie systematically below the spiral galaxy tully - fisher relation in both the optical and near - infrared ( figure 1 ) . if s0s are the descendants of spiral galaxies , this offset can be naturally interpreted as arising from the luminosity evolution of spiral galaxies that have faded since ceasing star formation . moreover , the amount of fading implied by the offset of individual s0s from the spiral relation seems to correlate with the luminosity - weighted age of their stellar population , particularly at their centres ( figure 2 ) .

Suppose that you have an abstract for a scientific paper: positive streamers in ambient air at pressures from 0.013 to 1 bar are investigated experimentally . the voltage applied to the anode needle ranges from 5 to 45 kv , the discharge gap from 1 to 16 cm . using a `` slow '' voltage rise time of 100 to 180 ns , the streamers are intentionally kept thin . for each pressure @xmath0 , we find a minimal diameter @xmath1 . to test whether streamers at different pressures are similar , the minimal streamer diameter @xmath2 is multiplied by its pressure @xmath0 ; we find this product to be well approximated by @xmath3 over two decades of air pressure at room temperature . the value also fits diameters of sprite discharges above thunderclouds at an altitude of 80 km when extrapolated to room temperature ( as air density rather than pressure determines the physical behavior ) . the minimal velocity of streamers in our measurements is approximately 0.1 mm / ns = @xmath4 m / s . the same minimal velocity has been reported for tendrils in sprites . we also investigate the size of the initial ionization cloud at the electrode tip from which the streamers emerge , and the streamer length between branching events . the same quantities are also measured in nitrogen with a purity of approximately 99.9% . we characterize the essential differences with streamers in air and find a minimal diameter of @xmath5 in our nitrogen . . And you have already written the first three sentences of the full article: streamer discharges determine the early stages of sparks and lightning ; they occur in various ionizable media in a large range of pressures and temperatures . in corona applications , they are widely used for surface charging in copiers and printers , for the removal of dust in electric precipitators and for ozone production and gas and water cleaning @xcite . streamers underlie the operation of spark plugs in internal combustion engines , and there are new initiatives to improve the control of ignition @xcite .. Please generate the next two sentences of the article

another new application is flow control in aviation @xcite . streamers also play a role in the ignition of energy efficient high pressure metal halid lamps @xcite . obviously , pressure , temperature and gas composition vary from one phenomenon to the next . in electrical engineering , the higher densities of liquids are desirable for fast switching , but pre - existing microbubbles largely influence streamer properties in fluids @xcite . for this reason ,

Suppose that you have an abstract for a scientific paper: we present in this paper multicolor surface and aperture photometry in the @xmath0 and @xmath1 bands for a sample of 34 lenticular galaxies from the ugc catalogue . from surface photometric analysis , we obtain radial profiles of surface brightness , colors , ellipticity , position angle and the fourier coefficients which describe the departure of isophotal shapes from purely elliptical form and find the presence of dust lanes , patches and ring like structure in several galaxies in the sample . we obtain total integrated magnitudes and colors and find that these are in good agreement with the values from the rc3 catalogue . isophotal colors are correlated with each other , following the sequence expected for early - type galaxies . the color gradients in lenticulars are more negative than the corresponding gradients in ellipticals . there is a good correlation between @xmath2 and @xmath3 color gradients , and the mean gradient in the @xmath4 and @xmath5 colors are @xmath6 , @xmath7 , @xmath8 magnitude per dex in radius respectively . . And you have already written the first three sentences of the full article: hubble ( 1936 ) introduced lenticular ( s0 ) galaxies as a morphological transition class between ellipticals and early - type spirals . the lenticular galaxies have disks with luminosity ranging from ten to hundred percent of the bulge luminosity , but without any conspicuous spiral arms . from their appearance , and also their stellar content , they seem to be more like ellipticals rather than spirals , and have often been misclassified due to this fact . it has been suggested ( van den bergh 1994 ) that there could be different , but overlapping , sub - populations amongst the lenticulars .. Please generate the next two sentences of the article

there are several scenarios possible for the formation of these galaxies . they could be of primordial origin , or could have been formed by the stripping of gas from spirals , which changes the morphology ( abadi , moore & bower 1999 ) , or through the mergers of unequal - mass spirals ( bekki 1998 ) . there could be a significant difference in the ages of disks and bulges , in which case they should have different stellar population , leading to different colors .

Suppose that you have an abstract for a scientific paper: we introduce the _ exchangeable rewiring process _ for modeling time - varying networks . the process fulfills fundamental mathematical and statistical properties and can be easily constructed from the novel operation of _ random rewiring_. we derive basic properties of the model , including consistency under subsampling , exchangeability , and the feller property . a reversible sub - family related to the erds rnyi model arises as a special case . ./style / arxiv - general.cfg . And you have already written the first three sentences of the full article: a recent influx of academic monographs @xcite and popular books @xcite manifests a keen cultural and scientific interest in complex networks , which appeal to both applied and theoretical problems in national defense , sociology , epidemiology , computer science , statistics , and mathematics . the erds rnyi random graph @xcite remains the most widely studied network model . its simple dynamics endow it with remarkable mathematical properties , but this simplicity overpowers any ability to replicate realistic structure .. Please generate the next two sentences of the article

many other network models have been inspired by empirical observations . chief among these is the _ scale - free _ phenomenon , which has garnered attention since the initial observation of power law behavior for internet statistics @xcite .

Suppose that you have an abstract for a scientific paper: we first survey the known results on functional equations for the double zeta - function of euler type and its various generalizations . then we prove two new functional equations for double series of euler - hurwitz - barnes type with complex coefficients . the first one is of general nature , while the second one is valid when the coefficients are fourier coefficients of a cusp form . . And you have already written the first three sentences of the full article: functional equations play a very important role in the theory of zeta and @xmath0-functions . in the case of the most classical riemann zeta - function @xmath1 , riemann proved the beautiful symmetric functional equation @xmath2 this symmetry , however , does not remain when we consider the hurwitz zeta - function @xmath3 , where @xmath4 . the functional equation for @xmath5 is of the form @xmath6 where @xmath7 and @xmath8 is the lerch zeta - function ( see ( * ? ? ? * ( 2.17.3 ) ) ) .. Please generate the next two sentences of the article

when @xmath9 , reduces to , but the form is no longer symmetric . in recent decades , the theory of various multiple zeta - functions has been developed extensively . therefore it is natural to search for functional equations for those multiple zeta - functions .

Suppose that you have an abstract for a scientific paper: for extremal black holes the fuzzball conjecture says that the throat of the geometry ends in a quantum ` fuzz ' , instead of being infinite in length with a horizon at the end . for the d1-d5 system we consider a family of sub - ensembles of states , and find that in each case the boundary area of the fuzzball satisfies a bekenstein type relation with the entropy enclosed . we suggest a relation between the ` capped throat ' structure of microstate geometries and the fact that the extremal hole was found to have zero entropy in some gravity computations . we examine quantum corrections including string 1-loop effects and check that they do not affect our leading order computations . epsf c black hole size and phase space volumes + + department of physics , + the ohio state university , + columbus , oh 43210 , usa + . And you have already written the first three sentences of the full article: it is a remarkable fact that the entropy of a black hole can be understood in terms of the surface area of its horizon @xcite . why is there such a connection between the size of the hole and its entropy ? in this paper we make a small observation that might be relevant to this connection .. Please generate the next two sentences of the article

let us consider extremal holes , using string theory . consider first the 3-charge system , which can be made with charges d1-d5-p wrapped on the cycles of a compactification @xmath0 @xcite . at weak coupling @xmath1 we can count the microstates that have charges @xmath2 , getting an entropy @xmath3 .

Suppose that you have an abstract for a scientific paper: recently we have proposed a reliable method to describe the rotational band in a fully microscopic manner . the method has recourse to the configuration - mixing of several cranked mean - field wave functions after the angular - momentum - projection . by applying the method with the gogny d1s force as an effective interaction , we investigate the moments of inertia of the ground state rotational bands in a number of selected nuclei in the rare earth region . as another application we try to describe , for the first time , the two - neutron aligned band in @xmath0er , which crosses the ground state band and becomes the yrast states at higher spins . fairly good overall agreements with the experimental data are achieved ; for nuclei , where the pairing correlations are properly described , the agreements are excellent . this confirms that the previously proposed method is really useful for study of the nuclear rotational motion . . And you have already written the first three sentences of the full article: the nuclear rotation is one of the most typical collective motions in nuclei @xcite . its semiclassical nature makes it possible to introduce the classical concepts like the rotational frequency and the transformation to the rotating frame , which are very useful to analyze the high - spin rotational bands @xcite and nowadays provide a standard method called the cranked shell model @xcite . however , the nucleus is a quantum many - body system and the basis of such a semiclassical treatment of the rotational motion is the symmetry breaking caused by the deformed mean - field , see e.g. @xcite .. Please generate the next two sentences of the article

in fact , the rotational motion emerges as a symmetry restoring collective motion of atomic nucleus as a whole and can be described full - quantum mechanically by the angular - momentum - projection method @xcite . although a nice rotational spectrum can be obtained by the angular - momentum - projection from the deformed mean - field state , it has been known that the level spacing of the obtained rotational spectrum tends to be larger than that of the experimental data ; i.e. the moment of inertia is quite often underestimated .

Suppose that you have an abstract for a scientific paper: the results of monte - carlo simulations of extensive air shower are presented to show the difference of hadronic component content at various altitudes with the aim to choose an optimal altitude for the prisma - like experiment . corsika program for eas simulations with qgsjet and gheisha models was used to calculate the number of hadrons reaching the observational level inside a ring of 50 m radius around the eas axis . then the number of neutrons produced by the hadronic component was calculated using an empirical relationship between the two components . we have tested the results with the protoprisma array at sea level , and recorded neutrons are close to the simulation results . _ keywords : eas , detector , neutrons , altitudes _ + . And you have already written the first three sentences of the full article: a novel type of extensive air shower ( eas ) array ( the prisma project ) has been proposed some years ago @xcite to study cosmic ray spectrum and mass composition in the `` knee '' region . existing experimental data in the knee region contradict each other and new approaches to the so - called `` knee problem '' are needed to solve this complicated and old problem . the prisma project is based on an idea that the main eas component - hadrons has to be measured first of all .. Please generate the next two sentences of the article

special detectors ( en - detectors ) have been developed for this purpose . it was proposed to combine the central part of the prisma array with the lhaaso project @xcite by introducing the en - detectors in the center of lhaaso array .

Suppose that you have an abstract for a scientific paper: a symmetric quandle is a quandle with a good involution . for a knot in @xmath0 , a knotted surface in @xmath1 or an @xmath2-manifold knot in @xmath3 , the knot symmetric quandle is defined . we introduce the notion of a symmetric quandle presentation , and show how to get a presentation of a knot symmetric quandle from a diagram . [ section ] [ theorem]definition [ theorem]corollary [ theorem]remark [ theorem]example [ theorem]lemma [ theorem]proposition . And you have already written the first three sentences of the full article: a _ rack _ is a set @xmath4 with a binary operation @xmath5 satisfying that ( 1 ) for any @xmath6 and @xmath7 of @xmath4 , there is a unique element @xmath8 with @xmath9 , and ( 2 ) for all @xmath10 , @xmath11 . a _ quandle _ is a rack satisfying that ( 3 ) @xmath12 for all @xmath13 . ( the condition ( 2 ) is called ( right ) self - distributivity .. Please generate the next two sentences of the article

refer to @xcite for details on algebras with this property . ) in @xcite , the _ knot quandle _ ( or the _ fundamental quandle _ ) of a knot is defined and it is proved that the knot quandle is a complete invariant of a classical knot up to orientations of knots and the ambient space .

Suppose that you have an abstract for a scientific paper: the combination of 7-year data from _ wmap _ and improved astrophysical data rigorously tests the standard cosmological model and places new constraints on its basic parameters and extensions . by combining the _ wmap _ data with the latest distance measurements from the baryon acoustic oscillations ( bao ) in the distribution of galaxies @xcite and the hubble constant ( @xmath0 ) measurement @xcite , we determine the parameters of the simplest 6-parameter @xmath1cdm model . the power - law index of the primordial power spectrum is @xmath2 ( 68% cl ) for this data combination , a measurement that excludes the harrison - zeldovich - peebles spectrum by 99.5% cl . the other parameters , including those beyond the minimal set , are also consistent with , and improved from , the 5-year results . we find no convincing deviations from the minimal model . the 7-year temperature power spectrum gives a better determination of the third acoustic peak , which results in a better determination of the redshift of the matter - radiation equality epoch . notable examples of improved parameters are the total mass of neutrinos , @xmath3 , and the effective number of neutrino species , @xmath4 ( 68% cl ) , which benefit from better determinations of the third peak and @xmath0 . the limit on a constant dark energy equation of state parameter from _ wmap_+bao+@xmath0 , without high - redshift type ia supernovae , is @xmath5 ( 68% cl ) . we detect the effect of primordial helium on the temperature power spectrum and provide a new test of big bang nucleosynthesis by measuring @xmath6 ( 68% cl ) . we detect , and show on the map for the first time , the tangential and radial polarization patterns around hot and cold spots of temperature fluctuations , an important test of physical processes at @xmath7 and the dominance of adiabatic scalar fluctuations . the 7-year polarization data have significantly improved : we now detect the temperature-@xmath8-mode polarization cross power spectrum at.... And you have already written the first three sentences of the full article: a simple cosmological model , a flat universe with nearly scale - invariant adiabatic gaussian fluctuations , has proven to be a remarkably good fit to ever improving cosmic microwave background ( cmb ) data @xcite , large - scale structure data @xcite , supernova data @xcite , cluster measurements @xcite , distance measurements @xcite , measurements of strong @xcite and weak @xcite gravitational lensing effects . observations of cmb have been playing an essential role in testing the model and constraining its basic parameters . the _ wmap _. Please generate the next two sentences of the article

satellite @xcite has been measuring temperature and polarization anisotropies of the cmb over the full sky since 2001 . with 7 years of integration , the errors in the temperature spectrum at each multipole are dominated by cosmic variance ( rather than by noise ) up to @xmath12 , and the signal - to - noise at each multipole exceeds unity up to @xmath13 @xcite .

Suppose that you have an abstract for a scientific paper: we define the flatness and quasi - flatness problems in cosmological models . we seek solutions to both problems in homogeneous and isotropic brans - dicke cosmologies with varying speed of light . we formulate this theory and find perturbative , non - perturbative , and asymptotic solutions using both numerical and analytical methods . for a particular range of variations of the speed of light the flatness problem can be solved . under other conditions there exists a late - time attractor with a constant value of @xmath0that is smaller than , but of order , unity . thus these theories may solve the quasi - flatness problem , a considerably more challenging problem than the flatness problem . we also discuss the related @xmath1 and quasi-@xmath2 problem in these theories . we conclude with an appraisal of the difficulties these theories may face . . And you have already written the first three sentences of the full article: the observable universe is close to a flat friedmann model , the so - called einstein - de sitter universe , in which the energy density , @xmath3 takes the critical value , @xmath4 , and the homogeneous spatial surfaces are euclidean . all astronomical evidence shows that we are quite close to this state of flatness , although a value of @xmath5 in the vicinity of @xmath6 is preferred by several observations . it is therefore disquieting to notice that the flat friedmann model containing dust or blackbody radiation is unstable as time increases .. Please generate the next two sentences of the article

small deviations from the exact @xmath7 model grow quickly in time , typically like @xmath8 , where @xmath9 is the expansion factor of the universe . the observed @xmath10 state therefore requires extreme fine tuning of the cosmological initial conditions , assumed to be set at planck epoch , because @xmath11 has increased by a factor of order @xmath12 from that epoch to the present .

Suppose that you have an abstract for a scientific paper: we study theoretically and experimentally influence of pancake vortices on motion of the josephson vortex lattice in layered high - temperature superconductors . mobility of the josephson vortices in layered superconductors is strongly suppressed by small amount of pancake - vortex stacks . moving josephson vortex lattice forces oscillating zigzag deformation of the pancake - vortex stacks contributing to damping . the salient feature of this contribution is its nonmonotonic dependence on the lattice velocity and the corresponding voltage . maximum pancake effect is realized when the josephson frequency matches the relaxation frequency of the stacks . the pancake - vortex damping is strongly suppressed by thermal fluctuations of the pancake vortices . this theoretical picture was qualitatively confirmed by experiments on two mesas prepared out of bi@xmath0sr@xmath1cacu@xmath1o@xmath2 whiskers . we found that the josephson - vortex flux - flow voltage is very sensitive to small c - axis magnetic field . the pancake - vortex contribution to the current indeed nonmonotonically depends on voltage and decreases with increasing temperature and in - plane magnetic field . we also found that irradiation with heavy ions has no noticeable direct influence on motion of the josephson vortices but dramatically reduces the pancake - vortex contribution to the damping of the josephson vortex lattice at low temperatures . . And you have already written the first three sentences of the full article: the layered crystalline structure of the cuprate high - temperature superconductors leads to existence of two types of vortices in these materials , pancake - vortex ( pv ) stacks @xcite induced by the magnetic field component perpendicular to the layers and josephson vortices ( jvs ) @xcite created by the magnetic field component parallel to the layers . repulsive interaction between the vortices of each type results in formation of regular vortex lattices . in particular , the magnetic field applied along the layers generates triangular lattice of the jvs stretched along the layer direction . the anisotropy factor @xmath3 sets the important field scale , @xmath4 , where @xmath5 is the interlayer periodicity .. Please generate the next two sentences of the article

when the magnetic field exceeds @xmath6 the josephson vortices homogeneously fill all layers forming a dense lattice @xcite . in highly anisotropic materials , like bi@xmath0sr@xmath0cacu@xmath0o@xmath2 ( bscco ) this field scale is rather moderate @xmath7 0.5 tesla . in bscco , due to a very weak josephson interlayer coupling

Suppose that you have an abstract for a scientific paper: we compare the outer radius of the accretion disc in the intermediate - mass black hole candidate hlx-1 as estimated from the uv / optical continuum , with the values estimated from its outburst decline timescales . we fit the _ swift _ 2010 outburst decline lightcurve with an exponential decay , a knee and a linear decay . we find that the disk has an outer radius @xmath0 cm @xmath1 cm , only an order of magnitude larger than typical accretion discs in the high / soft state of galactic black holes . by contrast , the semimajor axis is @xmath2 a few @xmath3 cm . this discrepancy can be explained with a highly eccentric orbit . we estimate the tidal truncation radius and circularization radius around the black hole at periastron , and impose that they are similar or smaller than the outer disk radius . we obtain that @xmath4 , that the radius of the donor star is @xmath5 a few solar radii , and that the donor star is not at risk of tidal disruption . if the companion star fills its roche lobe and impulsively transfers mass only around periastron , secular evolution of the orbit is expected to increase eccentricity and semimajor axis even further . we speculate that such extremely eccentric systems may have the same origin as the s stars in the galactic centre . [ firstpage ] accretion , accretion discs x - rays : individual : hlx-1 black hole physics . . And you have already written the first three sentences of the full article: the point - like x - ray source 2xmmj011028.1@xmath6460421 ( henceforth , hlx-1 for simplicity ) is the strongest intermediate - mass black hole ( imbh ) candidate known to date @xcite . it is seen in the sky at a distance of @xmath7 from the nucleus of the s0 galaxy eso243 - 49 ( redshift @xmath8 , luminosity distance @xmath9 mpc , distance modulus @xmath10 mag ; at this distance , @xmath11 pc ) . its x - ray luminosity and spectral variability @xcite and its radio flares detected in association with the x - ray outbursts @xcite are consistent with the canonical state transitions and jet properties of an accreting bh . with a peak x - ray luminosity @xmath12 erg s@xmath13 , the bh mass required to be consistent with the eddington limit is @xmath14 .. Please generate the next two sentences of the article

a similar value is obtained from spectral modelling of the thermal x - ray component , which is consistent with emission from an accretion disc @xcite . if these bh mass estimates are correct , hlx-1 is way too massive to have been formed from any stellar evolution process . a more likely scenario is that it is the nuclear bh ( perhaps still surrounded by its own nuclear star cluster ) of a disrupted dwarf satellite galaxy , accreted by eso243 - 49 @xcite .

Suppose that you have an abstract for a scientific paper: we present optical spectroscopic and photometric observations of supernova ( sn ) 2008d , associated with the luminous x - ray transient 080109 , at @xmath0 days after the explosion ( nebular phases ) . we also give flux measurements of emission lines from the region at the site of the sn , and estimates of the local metallicity . the brightness of the sn at nebular phases is consistent with the prediction of the explosion models with an ejected @xmath1ni mass of 0.07 @xmath2 , which explains the light curve at early phases . the [ ] line in the nebular spectrum shows a double - peaked profile while the [ ] line does not . the double - peaked [ ] profile strongly indicates that sn 2008d is an aspherical explosion . the profile can be explained by a torus - like distribution of oxygen viewed from near the plane of the torus . we suggest that sn 2008d is a side - viewed , bipolar explosion with a viewing angle of @xmath3 from the polar direction . . And you have already written the first three sentences of the full article: on 2008 january 9 , a luminous x - ray transient was serendipitously discovered in ngc 2770 during the follow - up observation of sn 2007uy in the same galaxy with the _ swift _ satellite @xcite . an optical counterpart was also discovered at the position of the transient @xcite , and it was named supernova ( sn ) 2008d @xcite . the total energy emitted at x - ray wavelengths is @xmath4 ergs , smaller than that of long gamma - ray bursts ( grbs ) by a factor of @xmath5 @xcite . the origin of the x - ray emission is being debated .. Please generate the next two sentences of the article

@xcite , @xcite , and @xcite interpreted the x - ray transient as a sn shock breakout . on the other hand , @xcite , @xcite and @xcite suggested that the transient is the least energetic end of grbs or x - ray flashes . sn 2008d is classified as type ib because of the presence of he lines @xcite while sne associated with grbs are all type ic ( without he lines ) .

Suppose that you have an abstract for a scientific paper: several multi - frequency polarization studies have shown the presence of systematic faraday rotation gradients across the parsec - scale jets of active galactic nuclei ( agn ) , taken to be due to the systematic variation of the line - of - sight component of a helical magnetic ( * b * ) field across the jet . other studies have confirmed the presence and sense of these gradients in several sources , thus providing evidence that these gradients persist over time and over large distances from the core . however , we find surprising new evidence for a reversal in the direction of the faraday rotation gradient across the jet of b1803 + 784 , for which multi - frequency polarization observations are available at four epochs . at our three epochs and the epoch of zavala & taylor ( 2003 ) , we observe transverse rotation measure ( rm ) gradients across the jet , consistent with the presence of a helical magnetic field wrapped around the jet . however , we also observe a `` flip '' in the direction of the gradient between june 2000 and august 2002 . although the origins of this phenomena are not entirely clear , possibly explanations include ( i ) the sense of rotation of the central supermassive black hole and accretion disc has remained the same , but the dominant magnetic pole facing the earth has changed from north to south ; ( ii ) a change in the direction of the azimuthal * b * field component as a result of torsional oscillations of the jet ; and ( iii ) a change in the relative contributions to the observed rotation measures of the `` inner '' and `` outer '' helical fields in a magnetic - tower model . although we can not entirely rule out the possibility that the observed changes in the rm distribution are associated instead with changes in the thermal - electron distribution in the vicinity of the jet , we argue that this explanation is unlikely . [ firstpage ] . And you have already written the first three sentences of the full article: bl lac objects are active galactic nuclei ( agn ) , characterized by strong and variable polarization , rapid variability in luminosity , a featureless spectrum and weak optical line emission . the radio emission associated with bl lac objects is synchrotron emission , which can be linearly polarized up to about 75% in the optically thin ( jet ) region , and up to 1015% in the optically thick ( core ) region ( pacholczyk 1970 ) . vlbi polarization observations of bl lac objects have shown a tendency for the polarization * e * vectors in the parsec - scale jets to be aligned with the local jet direction , which implies that the corresponding * b * field is transverse to the jet , because the jet is optically thin ( gabuzda , pushkarev & cawthorne 2000 ) .. Please generate the next two sentences of the article

although in the past , the dominance of the transverse * b * field component was suggested to be the consequence of a ` shock model ' where a series of relativistic shocks compress and enhance the transverse * b * field component ( laing 1980 ; hughes , aller & aller 1989 ) , this seems an improbable explanation for the transverse fields detected in extended regions in the jets of some sources . instead , a helical * b * field associated with the jet , with the toroidal component dominating over the longitudinal component , would be a more plausible explanation ( lyutikov , pariev & gabuzda 2005 ) . in fact , systematic gradients in the faraday rotation have been observed across the parsec - scale jets of a number of agn , interpreted as reflecting the systematic change in the line - of - sight component of a toroidal or helical jet * b * field across the jet ( asada et al .

Suppose that you have an abstract for a scientific paper: we discuss the role of the proximity force approximation in deriving limits to the existence of yukawian forces - predicted in the submillimeter range by many unification models - from casimir force experiments using the sphere - plane geometry . two forms of this approximation are discussed , the first used in most analysis of the residuals from the casimir force experiments performed so far , the second recently discussed in this context in r. decca _ et al . _ , [ phys . rev . d * 79 * , 124021 ( 2009 ) ] . we show that that the former form of the proximity force approximation overestimates the expected yukawa force and that the relative deviation from the exact yukawa force is of the same order of magnitude , in the realistic experimental settings , as the relative deviation expected between the exact casimir force and the casimir force evaluated in the proximity force approximation . this implies both a systematic shift making the actual limits to the yukawa force weaker than claimed so far , and a degree of uncertainty in the @xmath0 plane related to the handling of the various approximations used in the theory for both the casimir and the yukawa forces . we further argue that the recently discussed form for the proximity force approximation is equivalent , for a geometry made of a generic object interacting with an infinite planar slab , to the usual exact integration of any additive two - body interaction , without any need to invoke approximation schemes . if the planar slab is of finite size , an additional source of systematic error arises due to the breaking of the planar translational invariance of the system , and we finally discuss to what extent this may affect limits obtained on power - law and yukawa forces . . And you have already written the first three sentences of the full article: several unification schemes merging gravity and the standard model of strong and electroweak interactions predict the existence of short - range forces with coupling strength of the order of newtonian gravity @xcite . efforts to evidence a _ fifth force _ have been envisaged regardless of any concrete unification scheme since various decades @xcite , and there are compelling reasons to improve our limits especially in the largely unexplored submillimeter range .. Please generate the next two sentences of the article

constraints in both coupling and range for these interactions have been obtained with various experimental setups , including the recent configurations using a disk - shaped torsional balance parallel to a rotating flat surface @xcite , or micromechanical resonators in a parallel plane geometry @xcite . due to the surge of activity in the study of casimir forces , limits have been also given in the submicrometer range based on the level of accuracy between casimir theory and experiment .

Suppose that you have an abstract for a scientific paper: earth - mass dark matter microhalos with size of @xmath0 100 aus are the first structures formed in the universe , if the dark matter of the universe are made of neutralino . here , we report the results of ultra - high - resolution simulations of the formation and evolution of these microhalos . we found that microhalos have the central density cusps of the form @xmath1 , much steeper than the cusps of larger dark halos . the central regions of these microhalos survive the encounters with stars except in very inner region of the galaxy down to the radius of a few hundreds pcs from the galactic center . the annihilation signals from nearest microhalos are observed as gamma - ray point - sources ( radius less than 1 ) , with unusually large proper motions of @xmath2 degree per year . their surface brightnesses are @xmath010% of that of the galactic center . their s / n ratios might be better if they are far from the galactic plane . luminosities of subhalos are determined only by their mass , and they are more than one order of magnitude luminous than the estimation by @xcite : a boost factor can be larger than 1000 . perturbations to the millisecond pulsars by gravitational attractions of nearby earth - mass microhalos can be detected by the observations of parkes pulsar timing array ( ppta ) . . And you have already written the first three sentences of the full article: in our universe , dark matter halos evolve in the hierarchical fashion . smallest microhalos form first , and they merge with each other to form larger halos . the size of the smallest microhalos is determined by the scale of collisional damping and free streaming of dark matter particles . analytical studies @xcite predicted their mass to be @xmath3 , though uncertainty in theory of supersymmetry enlarges the interval further .. Please generate the next two sentences of the article

early studies @xcite suggested that a significant fraction of microhalos born in early universe have survived up to present time , and they might be observed as the dominant sources of the annihilation signal . these microhalos could enhance the annihilation signal by a factor of 2 to 5 @xcite , whose signature might have already been observed as electron and positron excess [ pamela @xcite , atic @xcite , ppb - bets @xcite , and fermi @xcite ] .

Suppose that you have an abstract for a scientific paper: in this letter we propose to quantify three qubit entanglement using global negativity along with @xmath0way negativities , where @xmath1 and @xmath2 . the principle underlying the definition of @xmath0way negativity for pure and mixed states of @xmath3subsystems is ppt sufficient condition . however , @xmath0way partial transpose with respect to a subsystem is defined so as to shift the focus to @xmath0way coherences instead of @xmath4 subsystems of the composite system . [ multiblock footnote omitted ] quantum entanglement is not only a fascinating aspect of multipartite quantum systems , but also a physical resource needed for quantum communication , quantum computation and information processing in general . bipartite entanglement is well understood , however , many aspects of multipartite entanglement are still to be investigated . peres @xcite and the horedecki @xcite have shown a positive partial transpose ( ppt ) of a bipartite density operator to be a sufficient criterion for classifying bipartite entanglement . negativity zycz98,vida00 based on peres horodecski criterion has been shown to be an entanglement monotone @xcite . negativity is a useful concept being related to the eigenvalues of partially transposed state operator and can be calculated easily . in this letter , we define @xmath5way and @xmath6way negativities and propose a classification of three qubit states based on measures related to global , @xmath5way and @xmath6way negativities . general definition of @xmath0way negativities for pure and mixed states of @xmath3subsystems is given in ref @xcite . the @xmath0way partial transpose with respect to a subsystem is defined so as to shift the focus to @xmath0way coherences instead of @xmath4 subsystems of the composite system . while pure @xmath0 partite entanglement of a composite system is generated by @xmath0way coherences , @xmath0partite entanglement can , in general , be present due to @xmath7 way coherences as well . . And you have already written the first three sentences of the full article: the hilbert space , @xmath8 associated with a quantum system composed of three qubits is spanned by basis vectors @xmath9 where @xmath10 or @xmath11 and @xmath12 . here @xmath13 is the dimension of hilbert space associated with @xmath14 qubit . to simplify the notation we denote the vector @xmath15 by @xmath16and write a general three qubit pure state as @xmath17to measure the overall entanglement of a subsystem @xmath18 we shall use twice the negativity as defined by vidal and werner @xcite , and call it global negativity @xmath19 . it is an entanglement measure based on peres - hororedecki @xcite npt ( negative partial transpose ) sufficient criterion for classifying bipartite entanglement .. Please generate the next two sentences of the article

the global partial transpose of @xmath20 ( eq.([1 ] ) ) with respect to sub - system @xmath21 is defined as@xmath22the partial transpose @xmath23 of an entangled state is not positive . global negativity , defined as@xmath24is an entanglement monotone and measures the entanglement of subsystem @xmath21 with its complement in a bipartite split of the composite system . global negativity vanishes on ppt - states and is equal to the entropy of entanglement on maximally entangled states .

Suppose that you have an abstract for a scientific paper: the interior structure of the sun can be studied with great accuracy using observations of its oscillations , similar to seismology of the earth . precise agreement between helioseismological measurements and predictions of theoretical solar models@xcite has been a triumph of modern astrophysics . however , a recent downward revision by 25 - 35% of the solar abundances of light elements such as c , n , o and ne@xcite has broken this accordance : models adopting the new abundances incorrectly predict the depth of the convection zone , the depth profiles of sound speed and density , and the helium abundance.@xcite the discrepancies are far beyond the uncertainties in either the data or the model predictions.@xcite here we report on neon abundances relative to oxygen measured in a sample of nearby solar - like stars from their x - ray spectra . they are all very similar and substantially larger than the recently revised solar value . the neon abundance in the sun is quite poorly determined . if the ne / o abundance in these stars is adopted for the sun the models are brought back into agreement with helioseismology measurements.@xcite harvard - smithsonian center for astrophysics , 60 garden street , cambridge ma 02138 , usa . mit kavli institute for astrophysics and space research , massachusetts institute for technology , 70 vassar street , cambridge , ma 02139 , usa . the role of the sun as a fundamental benchmark of stellar evolution theory , which itself underpins much of astrophysics , renders the `` solar model problem '' one of some importance . the schism between helioseismology and models with a revised composition has arisen because abundant elements such as c , n , o and ne provide major contributions to the opacity of the solar interior , which in turn influences internal structure and the depth at which the interior becomes convective . uncertainties in the calculated opacities themselves appear insufficient to bridge the gap,@xcite and the propriety of the recent.... And you have already written the first three sentences of the full article: we use the resonance lines of h - like o and of h - like and he - like ne to estimate the ne / o abundance ratio . in hot ( @xmath10-@xmath11 k ) coronal plasma these lines are formed predominantly by radiative de - excitation of levels excited by collisions with thermal electrons . the flux , @xmath12 , from such a transition @xmath13 in an ion of an element with abundance @xmath14 can be written as @xmath15 \;dt % \overline{n_e^2}(t)\ , \frac{dv(t)}{dt } \;dt \,\,\ , \mbox{erg cm$^{-2}$ s$^{-1}$ } \label{e : flux}\ ] ] where @xmath16 describes the line _ emissivity_the product of the relative population of the ion in question and the excitation rate of the transition as a function temperature , @xmath17 .. Please generate the next two sentences of the article

the kernel @xmath18the emission measure distribution describes the excitation power of the plasma as a function of temperature , which is proportional to the mean of the square of the electron density , @xmath19 , and the emitting volume @xmath20 , @xmath21 . if we can choose o and ne lines whose @xmath16 functions have very similar temperature dependence , an abundance ratio by number , @xmath22 , can be derived simply from the ratio of their observed line fluxes , @xmath23 and @xmath24 , since all the temperature - dependent terms in equation [ e : flux ] cancel : @xmath25 an early study of ne / o ratios in solar active regions@xcite used the ratio of ne ix @xmath26 to o viii @xmath27 .

Suppose that you have an abstract for a scientific paper: the analytic hierarchy process ( ahp ) is widely used for decision making involving multiple criteria . elsner and van den driessche @xcite introduced a max - algebraic approach to the single criterion ahp . we extend this to the multi - criteria ahp , by considering multi - objective generalisations of the single objective optimisation problem solved in these earlier papers . we relate the existence of globally optimal solutions to the commutativity properties of the associated matrices ; we relate min - max optimal solutions to the generalised spectral radius ; and we prove that pareto optimal solutions are guaranteed to exist . + _ keywords : _ analytic hierarchy process ( ahp ) , _ sr_-matrix , max algebra , subeigenvector , generalised spectral radius , multi - objective optimization . + _ ams codes : _ 91b06 , 15a80 , 90c29 . And you have already written the first three sentences of the full article: the analytic hierarchy process ( ahp ) is a method for ranking alternatives in multi - criteria decision making problems . developed by saaty @xcite , it consists of a three layer hierarchical structure : the overall goal is at the top ; the criteria are in the next level ; and the alternatives are in the bottom level . the ahp has been used in many different areas including manufacturing systems , finance , politics , education , business and industry ; for more details on the method , see the monographs by saaty - vargas and vaidya - kumar @xcite .. Please generate the next two sentences of the article

the essence of the ahp can be described as follows . given @xmath0 alternatives we construct a _ pairwise comparison matrix _ ( _ pc_-matrix ) , @xmath1 for each criterion , in which @xmath2 indicates the strength of alternative @xmath3 relative to alternative @xmath4 for that criterion . pc_-matrix with the property that @xmath5 for all @xmath6 and @xmath7 for all @xmath3 is called a _ symmetrically reciprocal _ matrix ( _ sr_-matrix ) @xcite .

Suppose that you have an abstract for a scientific paper: we investigate the voltage - driven transport of hybridized dna through membrane channels . as membrane channels are typically too narrow to accommodate hybridized dna , the dehybridization of the dna is the critical rate limiting step in the transport process . using a two - dimensional stochastic model , we show that the dehybridization process proceeds by two distinct mechanisms ; thermal denaturation in the limit of low driving voltage , and direct stripping in the high to moderate voltage regime . additionally , we investigate the effects of introducing non - homologous defects into the dna strand . . And you have already written the first three sentences of the full article: over the last two decades , the rapid development of single molecule manipulation techniques has produced dramatic advances in chemistry and molecular physics . the fields of dna biotechnology and nanofabrication in particular , have benefited from these advances . in turn , successes in the field of dna biotechnology have further motivated the study of dna manipulation techniques , with a strong focus on studying mechanisms of inducing dna dehybridization ( @xcite , @xcite ) . in this study , we consider dehybridizing dna by pulling dna molecules through a transmembrane channel . this work is motivated in part by the experimental results of nakane _. Please generate the next two sentences of the article

@xcite , and bates _ el al . _ @xcite . in the experiments of nakane , a probe dna that extends 14 base pairs beyond the opening of a trans - membrane channel

Suppose that you have an abstract for a scientific paper: a particular class of space - time , with a tachyon field , @xmath0 , and a barotropic fluid constituting the matter content , is considered herein as a model for gravitational collapse . for simplicity , the tachyon potential is assumed to be of inverse square form _ i.e. _ , @xmath1 . our purpose , by making use of the specific kinematical features of the tachyon , which are rather different from a standard scalar field , is to establish the several types of asymptotic behavior that our matter content induces . employing a dynamical system analysis , complemented by a thorough numerical study , we find classical solutions corresponding to a naked singularity or a black hole formation . in particular , there is a subset where the fluid and tachyon participate in an interesting tracking behaviour , depending sensitively on the initial conditions for the energy densities of the tachyon field and barotropic fluid . two other classes of solutions are present , corresponding respectively , to either a tachyon or a barotropic fluid regime . which of these emerges as dominant , will depend on the choice of the barotropic parameter , @xmath2 . furthermore , these collapsing scenarios both have as final state the formation of a black hole . . And you have already written the first three sentences of the full article: the study of the final state of the gravitational collapse of initially regular distributions of matter is one of the open problems in classical general relativity , having attracted remarkable attention in past decades . when a sufficiently massive star exhausts all the thermonuclear sources of its energy , it would undergo a collapsing scenario due to its own gravity , without reaching a final state in terms of a neutron star or white dwarf . under a variety of circumstances , singularities will inevitably emerge ( geodesic incompleteness in space - time ) , matter densities and space - time curvatures diverging . albeit the singularity theorems @xcite state that there exist space - time singularities in a generic gravitational collapse , they provide no information on the nature of singularities : the problem of whether these regions are hidden by a space - time event horizon or can actually be observed , remains unsolved .. Please generate the next two sentences of the article

the cosmic censorship conjecture ( ccc ) , as hypothesized by penrose @xcite , conveys that the singularities appearing at the collapse final outcome must be hidden within an event horizon and thus no distant observer could detect them . a black hole forms . although the ccc plays a crucial role in the physics of black holes , there is yet no proof of it , due to the lack of adequate tools to treat the global characteristics of the field equations .

Suppose that you have an abstract for a scientific paper: in the first paper of this series , we study the level population problem of recombining carbon ions . we focus our study on high quantum numbers anticipating observations of carbon radio recombination lines to be carried out by the low frequency array ( lofar ) . we solve the level population equation including angular momentum levels with updated collision rates up to high principal quantum numbers . we derive departure coefficients by solving the level population equation in the hydrogenic approximation and including low temperature dielectronic recombination effects . our results in the hydrogenic approximation agree well with those of previous works . when comparing our results including dielectronic recombination we find differences which we ascribe to updates in the atomic physics ( e.g. , collision rates ) and to the approximate solution method of the statistical equilibrium equations adopted in previous studies . a comparison with observations is discussed in an accompanying article , as radiative transfer effects need to be considered . . And you have already written the first three sentences of the full article: the interplay of stars and their surrounding gas leads to the presence of distinct phases in the interstellar medium ( ism ) of galaxies ( e.g. @xcite ) . diffuse atomic clouds ( the cold neutral medium , cnm ) have densities of about @xmath0 and temperatures of about @xmath1 , where atomic hydrogen is largely neutral but carbon is singly ionized by photons with energies between @xmath2 and @xmath3 . the warmer ( @xmath4 ) and more tenuous ( @xmath5 ) intercloud phase is heated and ionized by fuv and euv photons escaping from hii regions @xcite , usually referred to as the warm neutral medium ( wnm ) and warm ionized medium ( wim ) . the phases of the ism are often globally considered to be in thermal equilibrium and in pressure balance @xcite .. Please generate the next two sentences of the article

however , the observed large turbulent width and presence of gas at thermally unstable , intermediate temperatures attests to the importance of heating by kinetic energy input . in addition , the ism also hosts molecular clouds , where hydrogen is in the form of @xmath6 and self - gravity plays an important role .

Suppose that you have an abstract for a scientific paper: as a model of a novel superconductor na@xmath0coo@xmath1@xmath2@xmath3h@xmath1o , a single - band @xmath4-@xmath5 model on a triangular lattice is studied , using a variational monte carlo method . we calculate the energies of various superconducting ( sc ) states , changing the doping rate @xmath6 and sign of @xmath4 for small @xmath7 . symmetries of @xmath8 , @xmath9 , and @xmath9+@xmath10 ( @xmath11+@xmath12 and @xmath13 ) waves are taken up as candidates for singlet ( triplet ) pairing . in addition , the possibility of nagaoka ferromagnetism and inhomogeneous phases is considered . it is revealed that , among the sc states , the @xmath9+@xmath10 wave always has the lowest energy , which result supports previous mean - field studies . there is no possibility of triplet pairing , although the @xmath13-wave state becomes stable against a normal state in a special case ( @xmath14 and @xmath15 ) . for @xmath15 , the complete ferromagnetic state is dominant in a wide range of @xmath6 and @xmath7 , which covers the realistic parameter region of superconductivity . . And you have already written the first three sentences of the full article: the recent discovery of superconductivity @xcite in na@xmath16coo@xmath171.3h@xmath1o has aroused an active interest of solid state physicists , since this compound is regarded as a strongly correlated superconductor on a triangular lattice . for such magnetically frustrated lattices , novel superconducting ( sc ) features are expected , as compared to the celebrated cuprates on bipartite lattices . in particular , it is primarily important to determine the symmetry of its pairing potential .. Please generate the next two sentences of the article

so far , there have been a number of experimental efforts trying to fix the pairing symmetry , e.g. measurements of nuclear spin lattice relaxation rate @xmath18 @xcite , knight shift @xcite by nmr , and by @xmath19sr @xcite . at present , however , the results of these researches are not necessarily consistent to each another ; the pairing symmetry has not yet been established . as for theory , although some studies regard multiband effects as important , @xcite many treat this issue with reduced single - band models on a triangular lattice .

Suppose that you have an abstract for a scientific paper: we present an x - ray spectral and spatial analysis of the composite starburst / seyfert galaxy ngc1365 . excellent fits of the pspc spectrum are obtained by combining a soft thermal component with a hard powerlaw . the hard component may be either seen directly or can be explained by scattering of the agn powerlaw at circumnuclear warm high - column - density gas . a compilation of the multi - wavelength properties of ngc1365 and comparison with hard x - ray selected agns shows that the hard component of ngc1365 is too faint compared to its broad balmer line components challenging simple unified models . according to analytical estimates , supernova driven outflow can fully account for the x - ray luminosity in the raymond - smith component if the observed ir emission is mainly provided by the central starburst . we do not find obvious optical counterparts for three faint pspc sources south of the nucleus . in particular , there is no coincidence with the two supernovae reported in ngc1365 . with the hri data , we have precisely located the extraordinary southwest x - ray source ngc1365x1 which falls on one of the subordinate spiral arms . the source is found to be highly variable ( a factor @xmath0 10 ) on the timescale of months . intrinsic to ngc1365 , its huge luminosity makes it exceptional among stellar x - ray sources . at present , the most likely interpretation seems to be an ultra - powerful x - ray binary . . And you have already written the first three sentences of the full article: ngc1365 is a prominent barred spiral in the southern hemisphere . its nuclear and disk emission - line gas has been investigated in numerous optical studies ( e.g. , burbidge & burbidge 1960 , osmer et al . 1974 , veron et al . 1980 , alloin et al .. Please generate the next two sentences of the article

1981 , edmunds & pagel 1982 , phillips et al . 1983 , jrster et al .

Suppose that you have an abstract for a scientific paper: in this paper , we consider the adaptive eulerian lagrangian method ( elm ) for linear convection - diffusion problems . unlike the classical a posteriori error estimations , we estimate the temporal error along the characteristics and derive a new a posteriori error bound for elm semi - discretization . with the help of this proposed error bound , we are able to show the optimal convergence rate of elm for solutions with minimal regularity . furthermore , by combining this error bound with a standard residual - type estimator for the spatial error , we obtain a posteriori error estimators for a fully discrete scheme . we present numerical tests to demonstrate the efficiency and robustness of our adaptive algorithm . [ multiblock footnote omitted ] [ multiblock footnote omitted ] . And you have already written the first three sentences of the full article: convection - diffusion equations oftentimes arise in mathematical models for fluid dynamics , environmental modeling , petroleum reservoir simulation , and other applications . among them , the most challenging case for numerical simulation is the convection - dominated problems ( when diffusion effect is very small compared with the convection effect ) @xcite . dominated convection phenomena could appear in many real world problems ; for example , convective heat transport with large pclet numbers @xcite , simulation of oil extraction from underground reservoirs @xcite , reactive solute transport in porous media @xcite , etc .. Please generate the next two sentences of the article

the solutions of these problems usually have sharp moving fronts and complex structures ; their nearly hyperbolic nature presents serious mathematical and numerical difficulties . classical numerical methods , developed for diffusion - dominated problems , suffer from spurious oscillations for convection - dominated problems .

Suppose that you have an abstract for a scientific paper: we report the discovery and high - resolution , high @xmath0 , spectroscopic analysis of the ultra - metal - poor red giant he 0557@xmath14840 , which is the third most heavy - element deficient star currently known . its atmospheric parameters are @xmath2 = 4900k , @xmath3 = 2.2 , and [ fe / h ] = 4.75 . this brings the number of stars with [ fe / h ] @xmath4 4.0 to three , and the discovery of he 0557@xmath14840 suggests that the metallicity distribution function of the galactic halo does not have a gap " between [ fe / h ] = 4.0 , where several stars are known , and the two most metal - poor stars , at [ fe / h ] @xmath5 5.3 . he 0557@xmath14840 is carbon rich [ c / fe ] = + 1.6 a property shared by all three objects with @xmath6 } < -4.0 $ ] , suggesting that the well - known increase of carbon relative to iron with decreasing [ fe / h ] reaches its logical conclusion ubiquitous carbon richness at lowest abundance . we also present abundances ( nine ) and limits ( nine ) for a further 18 elements . for species having well - measured abundances or strong upper limits , he 0557@xmath14840 is normal " in comparison with the bulk of the stellar population at [ fe / h ] @xmath5 4.0 with the possible exception of co. we discuss the implications of these results for chemical enrichment at the earliest times , in the context of single ( `` mixing and fallback '' ) and two - component enrichment models . while neither offers a clear solution , the latter appears closer to the mark . further data are required to determine the oxygen abundance and improve that of co , and hence more strongly constrain the origin of this object . + he 05574840 ultra metal - poor and carbon - rich . And you have already written the first three sentences of the full article: the most metal - poor stars , believed to have formed at redshifts @xmath7 5 ( see e.g. * ? ? ? * ) , and representing well - defined points in space and time , hold clues on the conditions at the earliest epochs that are provided by no other astronomical objects . that is to say , the study of their metallicity distribution function ( mdf ) , together with their relative chemical abundance patterns , have the potential to shed light on the nature of the first generation of objects to form in the universe , and the manner in which the stellar - made elements ( those heavier than li ) first formed . consider first the mdf . four decades after the classic analysis of the archtypical metal - poor stars hd 19445 and hd 140283 by @xcite , it could be claimed ( e.g. * ? ? ?. Please generate the next two sentences of the article

* ) that the mdf for halo material with = log(n(fe)/n(h))@xmath8 log(n(fe)/n(h)@xmath9 , @xmath10 = log(n(fe)/n(h))@xmath8 + 12.00 ] [ fe / h ] @xmath7 4.0 was in reasonable agreement with the predictions of the simple closed box model of galactic chemical enrichment ( the simple model ) of @xcite and @xcite . following efforts since that time , however , it has become clear that this is not the case below [ fe / h ] @xmath4 4.0 : while two objects are currently known at [ fe / h ] @xmath5 5.3 ( he 01075840 , @xcite , and he 1327@xmath12326 , @xcite ) , the mdf presented by @xcite and the simple model lead one to expect some 40 such objects below [ fe / h ] = 4.0 . figure [ fig : lowfe_mdf ] , which shows the mdf for the unbiased metal - poor objects that have been the subject of high - resolution , high signal - to - noise ( @xmath0 ) model - atmosphere ( one - dimensional ( 1d ) , local thermodynamic equilibrium ( lte ) ) chemical abundance analyses @xmath4 2.0 .

Suppose that you have an abstract for a scientific paper: using the recent formulation of noether s theorem for the problems of the calculus of variations with fractional derivatives , the lagrange multiplier technique , and the fractional euler - lagrange equations , we prove a noether - like theorem to the more general context of the fractional optimal control . as a corollary , it follows that in the fractional case the autonomous hamiltonian does not define anymore a conservation law . instead , it is proved that the fractional conservation law adds to the hamiltonian a new term which depends on the fractional - order of differentiation , the generalized momentum , and the fractional derivative of the state variable . . And you have already written the first three sentences of the full article: the concept of symmetry plays an important role both in physics and mathematics . symmetries are described by transformations of the system , which result in the same object after the transformation is carried out . they are described mathematically by parameter groups of transformations .. Please generate the next two sentences of the article

their importance ranges from fundamental and theoretical aspects to concrete applications , having profound implications in the dynamical behavior of the systems , and in their basic qualitative properties . another fundamental notion in physics and mathematics is the one of conservation law .

Suppose that you have an abstract for a scientific paper: through studying the hard lags between the soft ( 3.3 5.8 kev ) and hard ( 13.0 41.0 kev ) photons of the 0.5 10 hz qpos in grs 1915 + 105 , we have classified them into three types : 0.5 2.0 hz qpos , 2.0 4.5 hz qpos , and 4.5 10 hz qpos . they are closely related to different temporal and spectral states . the first type of qpos ( 0.5 2 hz ) have positive hard lags at both the qpo fundamental and first harmonic frequencies . these qpos were observed in the quiescent soft state . the second type of qpos ( 2 4.5 hz ) , which were also detected in the quiescent soft state , have opposite signs of hard lags at the qpo fundamental and first harmonic frequencies . the third type ( 4.5 10 hz ) , which showed up in medium soft quiescent / out - burst states , do not have significant higher harmonic peaks . there is a smooth transition between these three types of qpo behaviors . we did not detect 0.5 10 hz qpos in the very soft state . we discuss some of the implications of these results . . And you have already written the first three sentences of the full article: the superluminal source grs 1915 + 105 displays a rich diversity of lightcurve morphology , power density spectrum ( pds ) , quasi - periodic oscillations ( qpos ) , phase lags , and coherence . the lightcurve morphology varies from out - burst to intermittent out - burst , to quiescence ( e.g. belloni et al . 1997 , 2000 ). Please generate the next two sentences of the article

. the pds shape can be either a broken power law with a flat top or a simple power law ( morgan , remillard , & greiner 1997 ) . the qpo fundamental frequency ranges from mhz to 67 hz ( e.g. morgan , remillard , & greiner 1997 ) , and some qpos were detected up to the third harmonic ( cui 1999 ) .

Suppose that you have an abstract for a scientific paper: the catalog and atlas of cataclysmic variables ( edition 1 - @xcite and edition 2 - @xcite ) has been a valuable source of information for the cataclysmic variable ( cv ) community . however , the goal of having a central location for all objects is slowly being lost as each new edition is generated . there can also be a long time delay between new information becoming available on an object and its publication in the catalog . to eliminate these concerns , as well as to make the catalog more accessible , we have created a web site which will contain a `` living '' edition of the catalog . we have also added orbital period information , as well as finding charts for novae , to the catalog . . And you have already written the first three sentences of the full article: the catalog and atlas of cataclysmic variables ( edition 1 - @xcite and edition 2 - @xcite ) has been a valuable source of information for the cataclysmic variable ( cv ) community . one of the goals of the catalog was to have the basic information on the objects ( i.e. coordinates , type , magnitude range , and finding charts ) in one central location , thus making it easy for observers to obtain data on the objects . however , the impracticality of reprinting the finding charts in their entirety means that , with each new edition , they are spread among more publications , taking us further from our goal of a central location .. Please generate the next two sentences of the article

furthermore , as new objects are discovered , and known ones examined in greater detail , the printed editions can not keep pace with discovery , a `` living '' edition is therefore highly desirable , so that observers can access a complete and current list of cvs at any time . for the above reasons , as well as the need to simplify the tracking of the objects ( there are over 1200 objects in the catalog ) , we have decided to generate a web - based version of the catalog .

Suppose that you have an abstract for a scientific paper: the bruggeman formalism provides an estimate of the effective permittivity of a particulate composite medium comprising two component mediums . the bruggeman estimate is required to lie within the wiener bounds and the hashin shtrikman bounds . considering the homogenization of weakly dissipative component mediums characterized by relative permittivities with real parts of opposite signs , we show that the bruggeman estimate may not be not physically reasonable when the component mediums are weakly dissipative ; furthermore , both the wiener bounds and the hashin shtrikman bounds exhibit strong resonances . * a limitation of the bruggeman formalism for homogenization * tom g. mackay + _ school of mathematics , university of edinburgh , edinburgh eh9 3jz , uk _ + akhlesh lakhtakia + _ catmas computational & theoretical materials sciences group + department of engineering science and mechanics + pennsylvania state university , university park , pa 168026812 , usa _ * keywords : * homogenization ; negative permittivity ; bruggeman formalism ; maxwell garnett formalism ; hashin shtrikman bounds ; wiener bounds . And you have already written the first three sentences of the full article: metamaterials in the form of particulate composite mediums are currently of considerable scientific and technological interest walser . provided that wavelengths are sufficiently long compared with the length scales of inhomogeneities , such a metamaterial may be envisaged as a homogenized composite medium ( hcm ) , arising from two homogeneous component mediums l96 , mackay03 . hcms with especially interesting properties may be conceptualized if the real parts of the relative permittivities ( and/or relative permeabilities ) of the two component mediums have opposite signs lijimmw .. Please generate the next two sentences of the article

this possibility arises for metal in insulator dielectric composites herwin , mlw01 and has recently become feasible with the fabrication of dielectric magnetic materials displaying a negative index of refraction in the microwave frequency range helby , smith . over many years

Suppose that you have an abstract for a scientific paper: we have developed a mechanical absolute - rotation sensor capable of resolving ground rotation angle of less than 1 nrad@xmath0 above @xmath1 mhz and 0.2 nrad@xmath0 above @xmath2 mhz about a single horizontal axis . the device consists of a meter - scale beam balance , suspended by a pair of flexures , with a resonance frequency of 10.8 mhz . the center of mass is located 3 @xmath3 m above the pivot , giving an excellent horizontal displacement rejection of better than @xmath4 rad / m . the angle of the beam is read out optically using a high - sensitivity autocollimator . we have also built a tiltmeter with better than 1 nrad@xmath0 sensitivity above 30 mhz . co - located measurements using the two instruments allowed us to distinguish between background rotation signal at low frequencies and intrinsic instrument noise . the rotation sensor is useful for rotational seismology and for rejecting background rotation signal from seismometers in experiments demanding high levels of seismic isolation , such as advanced ligo . . And you have already written the first three sentences of the full article: it is well known that horizontal seismometers are sensitive to ground rotation at low frequencies.@xcite indeed , due to the equivalence principle , conventional seismometers and tiltmeters can not distinguish between horizontal acceleration and rotation of the ground . while this is a problem in precision seismology , it is especially problematic for seismic isolation in next - generation gravitational - wave detectors , such as advanced laser interferometer gravitational - wave observatory ( aligo ) , where it is believed that rotation noise may limit improvements in low - frequency isolation.@xcite conventional horizontal seismometers can be idealized as horizontal spring - mass systems whose horizontal displacement is sensed relative to the housing . similarly , conventional tiltmeters or inclinometers can be idealized as vertical pendulums whose horizontal displacement is sensed relative to the housing . they are schematically represented in fig .. Please generate the next two sentences of the article

[ tiltaccel ] . by ` tilt ' , we henceforth refer to the angular deflection of a simple pendulum with respect to its suspension platform or enclosure . from the diagram of the horizontal seismometer ,

Suppose that you have an abstract for a scientific paper: we have developed a combined photolithography and electron - beam lithography fabrication process for sub-@xmath0 m to @xmath0m - size nb / al - alo@xmath1/nb josephson junctions . in order to define the junction size and protect its top electrode during anodic oxidation , we developed and used the new concept of an aluminum hard mask . josephson junctions of sizes down to 0.5 @xmath0m@xmath2 have been fabricated and thoroughly characterized . we found that they have a very high quality , which is witnessed by the @xmath3 curves with quality parameters @xmath4 mv and @xmath5 mv at 4.2 k , as well as @xmath6 products of @xmath7 mv obtained at lower temperatures . in order to test the usability of our fabrication process for superconducting quantum bits , we have also designed , fabricated and experimentally investigated phase qubits made of these junctions . we found a relaxation time of @xmath8 ns and a dephasing time of @xmath9 ns . . And you have already written the first three sentences of the full article: nb / al - alo@xmath1/nb josephson junctions ( jjs ) with sizes in the sub-@xmath0 m to @xmath0 m range are required or advantageous for many applications such as high - speed superconducting digital circuits ( rsfq ) , mm - wave receivers and submillimeter wave mixers , programmable voltage standards , squids and superconducting qubits . considering the multitude of possible applications , it is not surprising that several fabrication techniques for sub-@xmath0 m to @xmath0m - size junctions have been developed over the years . while a precise and reproducible definition of the jj size is routinely performed with the help of electron - beam lithography , the application of anodic oxidation in such processes remains a challenge . this is due to the fact that the nb@xmath10o@xmath11 layer formed during the anodic oxidation creeps under the resist mask protecting the top electrode of the jj ( this is known as `` encroachment '' @xcite ) . even for a plasma hardened resist and an anodization voltage of 20 v ,. Please generate the next two sentences of the article

a significant encroachment was still observed @xcite . some groups solve this problem by simply omitting the anodic oxidation or performing it at very low voltages below 10 v @xcite . since we found that a certain nb@xmath10o@xmath11 thickness is needed to ensure low subgap leakage currents , this was not an option for us . other groups have replaced the resist mask with an insulating hard mask such as sio or sio@xmath10 @xcite , which entirely eliminates the encroachment .

Suppose that you have an abstract for a scientific paper: we study the origin of layer dependence in band structures of two - dimensional materials . we find that the layer dependence , at the density functional theory ( dft ) level , is a result of quantum confinement and the non - linearity of the exchange - correlation functional . we use this to develop an efficient scheme for performing dft and gw calculations of multilayer systems . we show that the dft and quasiparticle band structures of a multilayer system can be derived from a single calculation on a monolayer of the material . we test this scheme on multilayers of mos@xmath0 , graphene and phosphorene . this new scheme yields results in excellent agreement with the standard methods at a fraction of the computation cost . this helps overcome the challenge of performing fully converged gw calculations on multilayers of 2d materials , particularly in the case of transition metal dichalcogenides which involve very stringent convergence parameters . . And you have already written the first three sentences of the full article: two - dimensional ( 2d ) materials have been extensively studied in the last decade @xcite owing to their applications in electronics and optoelectronics @xcite . 2d materials consist of layers that are held together by weak van der waals forces . a remarkable feature of these layered materials is the difference in properties of a monolayer compared to multilayers of the same material @xcite .. Please generate the next two sentences of the article

for instance , monolayer of mos@xmath0 has a direct band gap , while multilayers of mos@xmath0 have an indirect gap @xcite . most gapped 2d materials , like transition metal dichalcogenides ( tmdcs ) , hexagonal boron nitride and phosphorene , show an unmistakable reduction in band gap with the number of layers @xcite .

Suppose that you have an abstract for a scientific paper: blind compressed sensing ( bcs ) is an extension of compressed sensing ( cs ) where the optimal sparsifying dictionary is assumed to be unknown and subject to estimation ( in addition to the cs sparse coefficients ) . since the emergence of bcs , dictionary learning , a.k.a . sparse coding , has been studied as a matrix factorization problem where its sample complexity , uniqueness and identifiability have been addressed thoroughly . however , in spite of the strong connections between bcs and sparse coding , recent results from the sparse coding problem area have not been exploited within the context of bcs . in particular , prior bcs efforts have focused on learning constrained and complete dictionaries that limit the scope and utility of these efforts . in this paper , we develop new theoretical bounds for perfect recovery for the general _ unconstrained _ bcs problem . these unconstrained bcs bounds cover the case of overcomplete dictionaries , and hence , they go well beyond the existing bcs theory . our perfect recovery results integrate the combinatorial theories of sparse coding with some of the recent results from low - rank matrix recovery . in particular , we propose an efficient cs measurement scheme that results in practical recovery bounds for bcs . moreover , we discuss the performance of bcs under polynomial - time sparse coding algorithms . . And you have already written the first three sentences of the full article: the _ sparse representation _ problem involves solving the system of linear equations @xmath0 where @xmath1 is assumed to be @xmath2-sparse ; i.e. @xmath3 is allowed to have ( at most ) @xmath2 non - zero entries . the matrix @xmath4 is typically referred to as the _ dictionary _ with @xmath5 elements or _ atoms_. it is well - known that @xmath3 can be uniquely identified if @xmath6 satisfies the so called _ _ spark condition _. Please generate the next two sentences of the article

_ columns of @xmath6 are linearly independent . ] . meanwhile , there exist tractable and efficient convex relaxations of the combinatorial problem of finding the ( unique ) @xmath2-sparse solution of @xmath7 with provable recovery guarantees @xcite . a related problem is _ dictionary learning _ or _

Suppose that you have an abstract for a scientific paper: many methods have been proposed for community detection in networks . some of the most promising are methods based on statistical inference , which rest on solid mathematical foundations and return excellent results in practice . in this paper we show that two of the most widely used inference methods can be mapped directly onto versions of the standard minimum - cut graph partitioning problem , which allows us to apply any of the many well - understood partitioning algorithms to the solution of community detection problems . we illustrate the approach by adapting the laplacian spectral partitioning method to perform community inference , testing the resulting algorithm on a range of examples , including computer - generated and real - world networks . both the quality of the results and the running time rival the best previous methods . . And you have already written the first three sentences of the full article: the problem of community detection in networks has received wide attention @xcite . it has proved to be a problem of remarkable subtlety , computationally challenging and with deep connections to other areas of research including machine learning , signal processing , and spin - glass theory . a large number of algorithmic approaches to the problem have been considered , but interest in recent years has focused particularly on statistical inference methods @xcite , partly because they give excellent results , but also because they are mathematically principled and , at least in some cases , provably optimal @xcite . in this paper. Please generate the next two sentences of the article

we study two of the most fundamental community inference methods , based on the so - called stochastic block model or its degree - corrected variant @xcite . we show that it is possible to map both methods onto the well - known minimum - cut graph partitioning problem , which allows us to adapt any of the large number of available methods for graph partitioning to solve the community detection problem . as an example

Suppose that you have an abstract for a scientific paper: we give a closed formula for the multivariable conway potential function of any graph link in a homology sphere . as corollaries , we answer three questions by walter neumann @xcite about graph links . . And you have already written the first three sentences of the full article: a link @xmath0 in a homology @xmath1-sphere is called a _ graph link _ if its exterior is a graph manifold . for example , a link in @xmath2 is a graph link if and only if it is _ solvable _ , that is , if it can be constructed by iterated cabling and connected sum operations from the unknot . this class of links is particularly interesting , since all the links that arise in complex algebraic geometry are of this type .. Please generate the next two sentences of the article

eisenbud and neumann @xcite gave a classification of graph links by means of decorated trees called _ splice diagrams _ ; they also found a formula for the multivariable alexander polynomial @xmath3 of graph links in terms of the splice diagram ( see ( [ thm : multi - alex ] ) below ) .

Suppose that you have an abstract for a scientific paper: galaxy cluster merger statistics are an important component in understanding the formation of large - scale structure . cluster mergers are also potential sources of systematic error in the mass calibration of upcoming cluster surveys . unfortunately , it is difficult to study merger properties and evolution directly because the identification of cluster mergers in observations is problematic . we use large n - body simulations to study the statistical properties of massive halo mergers , specifically investigating the utility of close halo pairs as proxies for mergers . we examine the relationship between pairs and mergers for a wide range of merger timescales , halo masses , and redshifts ( @xmath0 ) . we also quantify the utility of pairs in measuring merger bias . while pairs at very small separations will reliably merge , these constitute a small fraction of the total merger population . thus , pairs do not provide a reliable direct proxy to the total merger population . we do find an intriguing universality in the relation between close pairs and mergers , which in principle could allow for an estimate of the statistical merger rate from the pair fraction within a scaled separation , but including the effects of redshift space distortions strongly degrades this relation . we find similar behavior for galaxy - mass halos , making our results applicable to field galaxy mergers at high redshift . we investigate how the halo merger rate can be statistically described by the halo mass function via the merger kernel ( coagulation ) , finding an interesting environmental dependence of merging : halos within the mass resolution of our simulations merge less efficiently in overdense environments . specifically , halo pairs with separations less than a few @xmath1 are more likely to merge in underdense environments ; at larger separations , pairs are more likely to merge in overdense environments . . And you have already written the first three sentences of the full article: galaxy clusters are of great interest in cosmology as they are the largest and most recently formed structures in the cosmological hierarchy . the clustering and number density evolution of clusters are sensitive to both the growth function and the expansion history of the universe . clusters contain a representative sample of baryons and dark matter and are thus also fascinating laboratories in which to study the influence of baryonic physics on the formation of large - scale structure , substructure , and its effect on the gravitational potential and dark matter halo shape .. Please generate the next two sentences of the article

statistical measures such as the mass function , the rate of structure growth , and the clustering of large structures , are fundamental predictions of cosmological models . cluster observations are therefore expected to provide some of the most important constraints on fundamental cosmology and astrophysics ( see e.g. @xcite for a recent review ) .

Suppose that you have an abstract for a scientific paper: motivated by experimental evidence for a mixed - valence state to occur in the neutralization of strontium ions on gold surfaces we analyze this type of charge - transferring atom - surface collision from a many - body theoretical point of view using quantum - kinetic equations together with a pseudo - particle representation for the electronic configurations of the atomic projectile . particular attention is paid to the temperature dependence of the neutralization probability which experimentally seems to signal mixed - valence - type correlations affecting the charge - transfer between the gold surface and the strontium projectile . we also investigate the neutralization of magnesium ions on a gold surface which shows no evidence for a mixed - valence state . whereas for magnesium excellent agreement between theory and experiment could be obtained , for strontium we could not reproduce the experimental data . our results indicate mixed - valence correlations to be in principle present , but for the model mimicking most closely the experimental situation they are not strong enough to affect the neutralization process quantitatively . . And you have already written the first three sentences of the full article: charge - exchange between an atomic projectile and a surface plays a central role in surface science . @xcite many surface diagnostics , for instance , secondary ion mass spectrometry @xcite or meta - stable atom de - excitation spectroscopy @xcite utilize surface - based charge - transfer processes . the same holds for plasma science . surface - based production of negative hydrogen ions , for instance , is currently considered as a pre - stage process in neutral gas heating of fusion plasmas .. Please generate the next two sentences of the article

@xcite the operation modii of low - temperature gas discharges @xcite , which are main work horses in many surface modification and semiconductor industries , depend on secondary electron emission from the plasma walls and thus also on surface - based charge - transfer processes . besides of their great technological importance , charge - transferring atom - surface collisions are however also of fundamental interest .

Suppose that you have an abstract for a scientific paper: the strong factorization conjecture states that a proper birational map between smooth algebraic varieties over a field of characteristic zero can be factored as a sequence of smooth blowups followed by a sequence of smooth blowdowns . we prove a local version of the strong factorization conjecture for toric varieties . combining this result with the monomialization theorem of s. d. cutkosky , we obtain a strong factorization theorem for local rings dominated by a valuation . . And you have already written the first three sentences of the full article: let @xmath0 be a proper birational map between smooth varieties over a field of characteristic zero . a commutative diagram @xmath1 where @xmath2 and @xmath3 are sequences of blowups of smooth centers , is called a strong factorization of @xmath4 . the existence of a strong factorization is an open problem in dimension @xmath5 and higher .. Please generate the next two sentences of the article

the local version of the strong factorization conjecture replaces the varieties by local rings dominated by a valuation on their common fraction field , and the smooth blowups by monoidal transforms along the valuation . the local strong factorization was proved by c. christensen @xcite in dimension @xmath6 for certain valuations .

Suppose that you have an abstract for a scientific paper: we present analysis of the shape and radial mass distribution of the e4 galaxy ngc 3923 using archival x - ray data from the _ rosat _ pspc and hri . the x - ray isophotes are significantly elongated with ellipticity @xmath0 ( 90% confidence ) for semi - major axis @xmath1 kpc and have position angles aligned with the optical isophotes within the estimated uncertainties . applying the geometric test for dark matter , which is independent of the gas temperature profile , we find that the ellipticities of the pspc isophotes exceed those predicted if @xmath2 at a marginal significance level of @xmath3 for oblate ( prolate ) symmetry . detailed hydrostatic models of an isothermal gas yield ellipticities for the gravitating matter , @xmath4 ( 90% confidence ) , which exceed the intensity weighted ellipticity of the @xmath5-band optical light , @xmath6 ( @xmath7 ) . we conclude that mass density profiles with @xmath8 are favored over steeper profiles if the gas is essentially isothermal ( which is suggested by the pspc spectrum ) and the surface brightness in the central regions @xmath9 is not modified substantially by a multi - phase cooling flow , magnetic fields , or discrete sources . we argue that these effects are unlikely to be important for ngc 3923 . ( the derived @xmath10 range is very insensitive to these issues . ) our spatial analysis also indicates that the allowed contribution to the _ rosat _ emission from a population of discrete sources with @xmath11 is significantly less than that indicated by the hard spectral component measured by _ asca_. galaxies : elliptical and lenticular , cd galaxies : fundamental parameters galaxies : individual ( ngc 3923 ) galaxies : structure x - rays : galaxies . . And you have already written the first three sentences of the full article: the structure of the dark matter halos of galaxies provides important clues to their formation and dynamical evolution ( e.g. sackett 1996 ; de zeeuw 1996 , 1997 ) . for example , in the cold dark matter ( cdm ) scenario ( e.g. ostriker 1993 ) there is evidence that the density profiles of halos have a universal form essentially independent of the halo mass or @xmath12 ( navarro , frenk , & white 1997 ; though see moore et al . the intrinsic shapes of cdm halos are oblate - triaxial with ellipticities similar to the optical isophotes of elliptical galaxies ( e.g. dubinski 1994 ) . the global shape of a halo also has implications for the mass of a central black hole ( e.g. merritt & quinlan 1997 ) .. Please generate the next two sentences of the article

at present accurate constraints on the intrinsic shapes and density profiles of early - type galaxies are not widely available ( e.g. sackett 1996 ; olling & merrifield 1997 ) . stellar dynamical analyses that have incorporated the information contained in high order moments of stellar velocity profiles have made important progress in limiting the uncertainty in the radial distribution of gravitating mass arising from velocity dispersion anisotropy ( rix et al .

Suppose that you have an abstract for a scientific paper: we study the effects of temperature and magnetic field on a two - orbital hubbard model within dynamical mean field theory . we focus on the quarter filled system , which is a special point in the phase diagram due to orbital degeneracy . at this particular filling the model exhibits two different long - range order mechanisms , namely orbital order and ferromagnetism . both can cooperate but do not rely on each other s presence , creating a rich phase diagram . particularly , in the vicinity of the phase transition to an orbitally ordered ferromagnetic state , we observe a strong magnetoresistance effect . besides the low temperature phase transitions , we also observe a crossover between a paramagnetic insulating and a paramagnetic metallic state for increasing hund s coupling at high temperatures . . And you have already written the first three sentences of the full article: strong correlations among the electrons and orbital degeneracy both play a major role in the low temperature physics of transition metal compounds @xcite . materials within this class range from the recently discovered superconducting iron pnictides to the manganites showing the colossal magnetoresistance . due to the short spatial extension of the 3d - orbitals in the transition metal atoms and the typical crystal structure of these compounds , screening of the coulomb interaction can be considered weak , leading to the above mentioned strong local electron - electron interactions . within the group of transition metal compounds , the cubic perovskite structure is a particularly common one . in this structure the 5-fold degenerate d - orbitals split into three - fold degenerate @xmath0-orbitals and two - fold degenerate @xmath1-orbitals .. Please generate the next two sentences of the article

therefore , besides strong correlations also orbital degeneracy will play an important role in these compounds . especially near integer filling , orbital degeneracy can induce long - range orbital order @xcite , for which the expectation value to find an electron in one orbital depends on the lattice site and the orbital .

Suppose that you have an abstract for a scientific paper: dynamical mass measurements to date have allowed determinations of the mass @xmath0 and the distance @xmath1 of a number of nearby supermassive black holes . in the case of sgr a * , these measurements are limited by a strong correlation between the mass and distance scaling roughly as @xmath2 . future very - long baseline interferometric ( vlbi ) observations will image a bright and narrow ring surrounding the shadow of a supermassive black hole , if its accretion flow is optically thin . in this paper , we explore the prospects of reducing the correlation between mass and distance with the combination of dynamical measurements and vlbi imaging of the ring of sgr a*. we estimate the signal to noise ratio of near - future vlbi arrays that consist of five to six stations , and we simulate measurements of the mass and distance of sgr a * using the expected size of the ring image and existing stellar ephemerides . we demonstrate that , in this best - case scenario , vlbi observations at 1 mm can improve the error on the mass by a factor of about two compared to the results from the monitoring of stellar orbits alone . we identify the additional sources of uncertainty that such imaging observations have to take into account . in addition , we calculate the angular diameters of the bright rings of other nearby supermassive black holes and identify the optimal targets besides sgr a * that could be imaged by a ground - based vlbi array or future space - vlbi missions allowing for refined mass measurements . . And you have already written the first three sentences of the full article: sgr a * , the supermassive black hole at the center of our galaxy , has been observed for several decades . monitoring stars orbiting around sgr a * has led to measurements of its mass and distance ( ghez et al . 2008 ; gillessen et al . 2009 ) . however , these measurements of mass and distance are strongly correlated . for purely astrometric measurements , mass and distance are related as @xmath3 , while for measurements of radial velocities mass and distance are related as @xmath4 . for combined data sets , the correlation between mass and distance behaves roughly as @xmath2 ( ghez et al .. Please generate the next two sentences of the article

2008 ; gillessen et al . this correlation between mass and distance constitutes a major source of uncertainty in our understanding of the properties of sgr a*. likewise , dynamical measurements of the masses of a number of nearby supermassive black holes have been obtained with often much greater uncertainties ( see , e.g. , gltekin et al .

Suppose that you have an abstract for a scientific paper: the non - exponential relaxation is shown to result from subordination by inverse tempered @xmath0-stable processes . the main feature of tempered @xmath0-stable processes is a finiteness of their moments , and the class of random processes includes ordinary @xmath0-stable processes as a particular case . starting with the cole - cole response this subordination approach establishes its direct link with the cole - davidson law . we derive the relaxation function describing the tempered relaxation . the meaning of the empirical response function is clarified . l@xmath1vy - stable process , subordination , non - exponential relaxation . And you have already written the first three sentences of the full article: the major feature of dynamical processes in many complex relaxing systems is their stochastic background @xcite . particularly , in any dielectric ( complex ) system under an week external electric field ( external action ) only a part ( active dipoles or objects ) of the total number of dipoles is directly governed by changes of the field . but even those dipoles , not contributing to the relaxation dynamics , can have an effect on the behavior of active dipoles @xcite . if the dipoles interact with each other , then their evolution has a random character .. Please generate the next two sentences of the article

consequently , the behavior of such a relaxing system as a whole will not be exponential in nature . in this case the macroscopic behavior of the complex systems is governed by `` averaging principles '' like the law of large numbers following from the theory of probability @xcite .

Suppose that you have an abstract for a scientific paper: the inert doublet model is one of the simplest and most versatile scenarios for physics beyond the standard model . in this work , we examine the prospects for detecting the additional fields of this model at the lhc in the dilepton channel . we investigate a wide variety of theoretically- and phenomenologically - motivated benchmark scenarios , and show that within regions of model parameter space in which the dark - matter candidate is relatively light ( between @xmath0 and @xmath1 gev ) and the mass splitting between the neutral scalars is also roughly @xmath2 gev , a signal at the @xmath3 to @xmath4 significance level can be observed with @xmath5 of integrated luminosity . in addition , even if the mass splitting between the neutral scalars is larger than @xmath6 , a signal of more than @xmath3 can be observed as long as the mass of the dark - matter candidate is around 40 gev . .7ex .7ex = cmss10 = cmss10 at 7pt . And you have already written the first three sentences of the full article: the inert doublet model @xcite ( idm ) is one of the simplest extensions of the standard model ( sm ) , yet it is also one of the most versatile . this scenario , in which the usual sm fields are supplemented by a single scalar @xmath7 doublet which does not contribute to electroweak - symmetry breaking ( ewsb ) and couples to the gauge - boson sector but not the fermion sector , has a wealth of potential phenomenological applications . perhaps the most intriguing of these stems from the recent observation @xcite that the fields of this additional scalar doublet can provide a positive contribution to the oblique @xmath8 parameter @xcite sufficient to render a sm higgs mass of @xmath9 gev consistent with precision data @xcite .. Please generate the next two sentences of the article

a host of other potential applications for inert doublets exist as well . these range from explaining the lightness of neutrino masses via a one - loop radiative see - saw mechanism @xcite to the loop - level induction of electroweak - symmetry breaking @xcite to engineering successful grand unification @xcite .

Suppose that you have an abstract for a scientific paper: we study degenerations of bethe subalgebras @xmath0 in the yangian @xmath1 , where @xmath2 is a regular diagonal matrix . we show that closure of the parameter space of the family of bethe subalgebras is the deligne - mumford moduli space of stable rational curves @xmath3 and state a conjecture generalizing this result to bethe subalgebras in yangians of arbitrary simple lie algebra . we prove that all subalgebras corresponding to the points of @xmath3 are free and maximal commutative . we also describe explicitly the `` simplest '' degenerations and show that every degeneration is the composition of the simplest ones . . And you have already written the first three sentences of the full article: yangian for @xmath4 is the associative algebra historically one of the first examples of _ quantum groups_. the yangian @xmath1 is a hopf algebra deforming the enveloping algebra @xmath5)$ ] , where @xmath6 $ ] is the ( infinite dimensional ) lie algebra of @xmath4-valued polynomials . this algebra was considered in the works of l. fadeev and st .- petersburg school in the relation with the inverse scattering method , see e.g. @xcite . there is a family @xmath0 of commutative subalgebras in @xmath1 parameterized by complex matrices @xmath7 called bethe subalgebras . this family originates from the integrable models in statistical mechanics and algebraic bethe ansatz . for details and links on yangians , we refer the reader to the survey @xcite and to the book @xcite by a. molev .. Please generate the next two sentences of the article

denote by @xmath8 the maximal torus in @xmath9 i.e. the subgroup of diagonal matrices in @xmath9 . in the present paper we restrict ourselves to bethe subalgebras with @xmath10 .

Suppose that you have an abstract for a scientific paper: we have calculated the non - radial oscillation in slowly rotating relativistic stars with the cowling approximation . the frequencies are compared with those based on the complete linearized equations of general relativity . it is found that the results with the approximation differ by less than about @xmath0 for typical relativistic stellar models . the approximation is more accurate for higher - order modes as in the newtonian case . oscillation , neutron star . And you have already written the first three sentences of the full article: in recent years , our understanding of pulsations of non - rotating relativistic stars has been much improved . in particular , the role of gravitational wave in the stars becomes much clear . there exists the oscillation mode named as w - mode ( gravitational _ w_ave mode ) , associated with the gravitational wave . the gravitational wave is inherent in the general relativity , so that the mode becomes evident only for relativistic system . except for this new mode ,. Please generate the next two sentences of the article

the relativity little affects the modes known in the newtonian pulsation theory . the general relativity slightly changes the oscillation frequency and gives rise to a very slow damping of the mode .

Suppose that you have an abstract for a scientific paper: irreversible diffusion limited cluster aggregation ( dlca ) of hard spheres was simulated using brownian cluster dynamics . bound spheres were allowed to move freely within a specified range , but no bond breaking was allowed . the structure and size distribution of the clusters was investigated before gelation . the pair correlation function and the static structure factor of the gels were determined as a function of the volume fraction and time . bond flexibility led to local densification of the clusters and the gels , with a certain degree of order . at low volume fractions densification of the clusters occurred during their growth , but at higher volume fractions it occurred mainly after gelation . at very low volume fractions , the large scale structure ( fractal dimension ) , size distribution and growth kinetics of the clusters was found to be close to that known for dlca with rigid bonds . restructuring of the gels continued for long times , indicating that aging processes in systems with strong attraction do not necessarily involve bond breaking . the mean square displacement of particles in the gels was determined . it is shown to be highly heterogeneous and to increase with decreasing volume fraction . . And you have already written the first three sentences of the full article: strong attraction between particles in solution leads to aggregation . the kinetics of this aggregation process depends on the probability that a bond is formed when two particles collide . two limiting cases are diffusion limited cluster aggregation ( dlca ) if bonds are formed at each collision and reaction limited cluster aggregation ( rlca ) if the probability to form a bond is very small . irreversible aggregation has been studied in detail both experimentally @xcite and using computer simulations @xcite .. Please generate the next two sentences of the article

the structure of clusters formed by random aggregation is self similar and characterized by a fractal dimension ( @xmath0 ) , which relates the radius of gyration ( @xmath1 ) to the aggregation number ( @xmath2 ) : @xmath3 . the number of clusters with aggregation number @xmath2 can be described by a power law : @xmath4 .

Suppose that you have an abstract for a scientific paper: josephson junction systems with a negative differential resistance play an essential role for applications . as a well known example , long josephson junctions of the bscco type have been considered as a source of thz radiation in recent experiments . numerical results for the dynamics of the fluxon system have demonstrated that a cavity induced negative differential resistance plays a crucial role for the emission of electromagnetic radiation . we consider the case of a negative differential resistance region in the mccumber curve itself of a single junction and found that it has an effect on the emission of electromagnetic radiation . two different shapes of negative differential resistance region are considered and we found it is essential to distinguish between current bias and voltage bias . + + _ keywords : millimeter wave devices , superconducting devices , nonlinear circuits , nonlinear optics , nonlinear oscillators _ . And you have already written the first three sentences of the full article: fluxon dynamics in long josephson junctions is a topic of strong interest due to its rich nonlinear properties and applications in fast electronics , in particular as a radiation source at high frequencies @xcite . an extension of that system is to form a metamaterial by stacking several josephson junctions on top of each other , which are modeled by @xmath0 coupled partial differential equations . such superconductors are employed in a variety of devices ( stacks , flux - flow devices , and synchronized arrays ) and are capable of power emission in the range 0.5 - 1 thz .. Please generate the next two sentences of the article

integration in arrays could give an improvement in the power performances , above @xmath1 @xcite . practical applications are especially in the field of bio - sensing , nondestructive testing and high speed wireless communications @xcite . for such reasons

Suppose that you have an abstract for a scientific paper: the weak production of lambdas in nucleon - nucleon scattering is studied in a meson - exchange framework . the weak transition operator for the @xmath0 reaction is identical to a previously developed weak strangeness - changing transition potential @xmath1 that describes the nonmesonic decay of hypernuclei . the initial @xmath2 and final @xmath3 state interaction has been included by using realistic baryon - baryon forces that describe the available elastic scattering data . the total and differential cross sections as well as the parity - violating asymmetry are studied for the reaction pn @xmath4 p@xmath5 . these observables are found to be sensitive to the opening of the @xmath6 production channel , the choice of the strong interaction potential and the structure of the weak transition potential . # 1#2@xmath7#2 # 1eq . ( [ # 1 ] ) 12@xmath8c 11@xmath9b 5@xmath10he # 1#1| # 1| # 1 . And you have already written the first three sentences of the full article: over the last several decades , the standard model of weak interactions has been thoroughly tested by a vast amount of data for leptonic and semi- leptonic decays and reactions . hadronic weak interactions are in general more difficult to study experimentally since they are usually obscured by the presence of the much larger strong interaction . this requires employing processes in which the strong force can not participate due to overriding symmetry principles . in the case of the weak nucleon - nucleon interaction. Please generate the next two sentences of the article

it was realized more than 40 years ago@xcite that the current - current form of the weak interaction dictates the presence of a weak transition between nucleons which would lead to parity impurities in nuclear states which are of first order in the weak coupling . using these parity nonconserving observables in many experiments on nuclear gamma and alpha transitions , polarized @xmath2 scattering , as well as the recent first measurement of the nuclear anapole moment@xcite , much has been learned about the weak nucleon - nucleon interaction@xcite .

Suppose that you have an abstract for a scientific paper: we perform a study on the optical and infrared photometric properties of known luminous blue variables ( lbvs ) in m31 using the sample of lbv candidates from the local group galaxy survey @xcite . we find that m31 lbv candidates show photometric variability ranging from 0.375 to 1.576 magnitudes in @xmath0 during a three year time - span observed by the pan - starrs 1 andromeda survey ( pandromeda ) . their near - infrared colors also follow the distribution of galactic lbvs as shown by . we use these features as selection criteria to search for unknown lbv candidates in m31 . we thus devise a method to search for candidate lbvs using both optical color from the local group galaxy survey and infrared color from two micron all sky survey , as well as photometric variations observed by pandromeda . we find four sources exhibiting common properties of known lbvs . these sources also exhibit uv emission as seen from _ galex _ , which is one of the previously adopted method to search for lbv candidates . the locations of the lbvs are well aligned with m31 spiral arms as seen in the uv light , suggesting they are evolved stars at young age given their high - mass nature . we compare these candidates with the latest geneva evolutionary tracks , which show that our new m31 lbv candidates are massive evolved stars with an age of 10 to 100 million years . . And you have already written the first three sentences of the full article: luminous blue variables are hot massive stars which undergo sporadic eruptions on timescales of years and decades @xcite . the prototype is s doradus , as well as hubble - sandage variables in m31 and m33 @xcite , which shows eruptions of 1 - 2 magnitude level in a time - span of several decades . other examples are @xmath1 carina and p cygni , which show giant eruptions ( @xmath2 2 mag ) at a frequency of several centuries .. Please generate the next two sentences of the article

@xcite is the first to coin the name luminous blue variables for this type of stars , and separates them from other type of bright blue stars like wolf - rayet stars . lbvs play an important role at the very late stage of massive star evolution .

Suppose that you have an abstract for a scientific paper: a new next - to - leading order monte carlo program for the calculation of jet cross sections in photoproduction is described . the contributions from both resolved and direct components are included to @xmath0 . properties of the predictions for various inclusive jet and dijet observables are discussed and comparisons with hera data are presented . . And you have already written the first three sentences of the full article: electromagnetic interactions have long been used to study both hadronic structure and strong interaction dynamics . examples include deep inelastic lepton - nucleon scattering , hadronic production of lepton pairs , the production of photons with large transverse momenta , and various photoproduction processes involving the scattering of real or very low mass virtual photons from hadrons . in particular , the photoproduction of jets with large transverse momenta is calculable in qcd and offers additional complementary information to that obtained from the study of the hadroproduction of jets @xcite . in the photoproduction case. Please generate the next two sentences of the article

there are contributions where the photon s energy contributes entirely to the hard - scattering subprocess ; these are often referred to collectively as the direct component . in addition , a real photon can interact via its hadronic substructure .

Suppose that you have an abstract for a scientific paper: recently , the hess telescope has observed a gamma - ray spectrum from the galactic center extending to at least @xmath010 tev . although it has been suggested that this could be the product of annihilating dark matter particles , the candidates most frequently discussed ( such as neutralinos ) are far too light to account for this flux . in this letter , we consider stable particles from the messenger sector of gauge mediated supersymmetry breaking models as an alternative dark matter candidate . we find that a 20 to 30 tev messenger state can provide a thermal relic density consistent with the measured dark matter density of the universe and can indeed generate the spectrum observed by hess . @xmath1 0.5 cm . And you have already written the first three sentences of the full article: recently , the high - energy spectroscopic system ( hess ) collaboration has reported the detection of gamma - rays from the region of the galactic center with energies ranging between approximately 250 gev and 10 tev @xcite . two other atmospheric cerenkov telescopes ( acts ) , cangaroo - ii @xcite and whipple @xcite have also reported positive detections of very high - energy gamma - rays from the region , although with considerably lower significance . currently , the origin of this very high - energy emission is unknown .. Please generate the next two sentences of the article

efforts have been made to explain the data with astrophysical processes involving the supermassive black hole known to exist at the galactic center @xcite . although these are certainly possible explanations , the source of the observed emission is not yet clear . gamma - ray observations of the galactic center have long been studied as one of the most promising methods to search for particle dark matter @xcite .

Suppose that you have an abstract for a scientific paper: recent ultracold atomic gas experiments implementing synthetic spin - orbit coupling allow access to flatbands that emphasize interactions . we model spin - orbit coupled fermions in a one - dimensional flat band optical lattice . we introduce an effective luttinger - liquid theory to show that interactions generate collective excitations with emergent kinetics and fractionalized charge , analogous to properties found in the two - dimensional fractional quantum hall regime . observation of these excitations would provide an important platform for exploring exotic quantum states derived solely from interactions . _ introduction . _ emergent quantum states derived from interactions can exhibit rich structure because they are , by definition , not adiabatically connected to the underlying single - particle states . two - dimensional ( 2d ) electron gases placed in a strong magnetic field offer seminal examples . in the absence of a magnetic field , 2d electrons typically demonstrate fermi - liquid behavior , but a strong magnetic field , the fractional quantum hall ( fqh ) limit @xcite , would seem to prevent the formation of a fermi liquid . this regime is defined by an absence of single - particle kinetic energy that leaves inter - particle interactions to generate many - body quantum states in a flatband ( the lowest landau level ) . however , it is now well known that interesting properties , such as fractional charge from screening and other kinetic effects @xcite , emerge from interactions in the fqh regime . the remarkable fact that application of an external field first suppresses single - particle properties to leave interactions to generate similar emergent properties leads to a natural question : can these emergent mechanisms manifest in other contexts ? flatbands in one dimension offer a logical analogue @xcite . the luttinger - liquid paradigm @xcite captures the physics of many one - dimensional ( 1d ) models . it predicts excitations with , e.g. , fractionalized.... And you have already written the first three sentences of the full article: in this section we derive the flat band projected hamiltonian , eq . ( 2 ) , by adding interactions to eq . ( 1 ) . we first use the tight - binding limit to show that flat bands arise from spin - orbit coupled fermions in optical lattices in the absence of interactions . using the tight - binding limit. Please generate the next two sentences of the article

we transform the interaction to an on - site hubbard interaction . we then project the interaction into the flat band to derive eq .

Suppose that you have an abstract for a scientific paper: enzymes utilize protein architectures to create highly specialized structural motifs that can greatly enhance the rates of complex chemical transformations . here we use experiments , combined with _ ab initio _ simulations that exactly include nuclear quantum effects , to show that a triad of strongly hydrogen bonded tyrosine residues within the active site of the enzyme ketosteroid isomerase ( ksi ) facilitates quantum proton delocalization . this delocalization dramatically stabilizes the deprotonation of an active site tyrosine residue , resulting in a very large isotope effect on its acidity . when an intermediate analog is docked , it is incorporated into the hydrogen bond network , giving rise to extended quantum proton delocalization in the active site . these results shed light on the role of nuclear quantum effects in the hydrogen bond network that stabilizes the reactive intermediate of ksi , and the behavior of protons in biological systems containing strong hydrogen bonds . . And you have already written the first three sentences of the full article: while many biological processes can be well described with classical mechanics , there has been much interest and debate as to the role of quantum effects in biological systems ranging from photosynthetic energy transfer , to photoinduced isomerization in the vision cycle and avian magnetoreception @xcite . for example , nuclear quantum effects , such as tunneling and zero - point energy ( zpe ) , have been observed to lead to _ kinetic _ isotope effects of greater than 100 in biological proton and proton - coupled electron transfer processes @xcite . however , the role of nuclear quantum effects in determining the ground state thermodynamic properties of biological systems , manifesting as _ equilibrium _ isotope effects , has gained significantly less attention @xcite . intermediate and ksi@xmath0inhibitor complex .. Please generate the next two sentences of the article

schematic depiction of ( a ) the ksi@xmath1intermediate complex during the catalytic cycle ( fig . s1 ) and ( b ) a complex between ksi@xmath2 and phenol , an inhibitor which acts as an intermediate analog .

Suppose that you have an abstract for a scientific paper: l and m band observations of the nova - like variable v4332 sgr are presented . two significant results are obtained viz . the unusual detection of water ice at 3.05@xmath0 m and the fundamental band of @xmath1co at 4.67@xmath0 m in emission . the ice feature is a first detection in a nova - like variable while the co emission is rarely seen in novae . these results , when considered together with other existing data , imply that v4332 sgr could be a young object surrounded by a circumstellar disc containing gas , dust and ice . the reason for a nova - like outburst to occur in such a system is unclear . but since planets are believed to form in such disks , it appears plausible that the enigmatic outburst of v4332 sgr could be due to a planetary infall . we also give a more reliable estimate for an epoch of dust formation around v4332 sgr which appears to have taken place rather late in 1999 - nearly five years after its outburst . . And you have already written the first three sentences of the full article: we present here l and m band results on v4332 sgr . recent studies of v4332 sgr have shown that it is an interesting object and the present results further support this view . v4332 sgr erupted in 1994 in a nova - like outburst with an outburst amplitude of 9.5 magnitude in the visible region .. Please generate the next two sentences of the article

there was only one detailed study of the object during its outburst ( martini et al . 1999 ) which showed that its eruption was different from that of a classical nova or other classes of eruptive variables .

Suppose that you have an abstract for a scientific paper: in cosmological structure formation models , massive non linear objects in the process of formation , such as galaxy clusters , are surrounded by large - scale shocks at or around the expected virial radius . direct observational evidence for such virial shocks is currently lacking , but we show here that their presence can be inferred from future , high resolution , high sensitivity observations of the sunyaev - zeldovich ( sz ) effect in galaxy clusters . we study the detectability of virial shocks in mock sz maps , using simple models of cluster structure ( gas density and temperature distributions ) and noise ( background and foreground galaxy clusters projected along the line of sight , as well as the cosmic microwave background anisotropies ) . we find that at an angular resolution of @xmath0 and sensitivity of @xmath1 , expected to be reached at @xmath2 ghz frequencies in a @xmath3hr integration with the forthcoming alma instrument , virial shocks associated with massive ( @xmath4 ) clusters will stand out from the noise , and can be detected at high significance . more generally , our results imply that the projected sz surface brightness profile in future , high resolution experiments will provide sensitive constraints on the density profile of cluster gas . . And you have already written the first three sentences of the full article: in cosmological theories of structure formation , non linear objects form when overdense dark matter perturbations turn around , collapse , and settle into virial equilibrium ( e.g. @xcite and references therein ) . gas initially collapses together with the dark matter , but eventually encounters nearly stationary material that had already collapsed . since the gas is falling in at supersonic velocities , it is slowed down by hydrodynamical shocks , and these shocks are thought to heat the gas to the virial temperature of the dark matter halo . in spherically symmetric models , and in the absence of dissipation ,. Please generate the next two sentences of the article

a single strong gaseous shock occurs at approximately half of the turn around radius @xcite , coinciding with the `` virial radius '' of the dark matter halo . more realistically , the behavior of the post shock gas depends sensitively on its cooling time @xcite . on galactic scales ( @xmath5 ) and below , and increasingly toward high redshifts ( @xmath6 ) , the gas can cool rapidly and loose its pressure support , and hence continue its infall . on these scales , the existence of large

Suppose that you have an abstract for a scientific paper: a unique , essentially complete sample of 22 qsos , with high quality soft x - ray spectra from rosat , as well as hst and optical spectrophotometry from below ly@xmath0 to above h@xmath0 , is being used to investigate the relationships among the ionizing continuum and the optical and uv continuum , emission and absorption lines . here we present a first analysis showing that optical ` eigenvector 1 ' linking steeper soft x - ray spectra with increasing optical feii strength , decreasing [ oiii]@xmath15007 emission , and narrower blr h@xmath2 emission , extends to the uv emission lines , and is manifested by weaker civ@xmath11549 emission , stronger siiii]@xmath11892/ciii]@xmath11909 ratio , and narrower ciii]@xmath11909 emission . steeper soft x - ray spectra have been linked to higher l / l@xmath3 ratios , thus apparently linking blr densities , high and low ionization gas , and kinematics , to the accretion process . . And you have already written the first three sentences of the full article: in principle , relationships between qsos euv continuum and the emission - line gas that it ionizes should give us clues to any relationship between accretion power and the physical conditions and kinematics of accreting or outflowing material within @xmath4 1 pc , hence clues to the mechanism of the central engine . several studies have shown that the soft x - ray spectrum is related to the emission line spectrum : steeper x - ray spectra are associated with stronger optical feii ( blr ) emission , narrower ( blr ) h@xmath2 , weaker [ oiii]@xmath15007 ( nlr ) emission ( boroson & green 1992 ; grupe 1996 ; grupe et al . 1998 ; forster 1995 ; laor et al . 1994 , 1997 ; corbin 1993 ) .. Please generate the next two sentences of the article

one of the greatest sources of variation from one spectrum to another can be represented as a linear combination of these observables the so - called `` eigenvector 1 '' of principal component analyses . its underlying physical cause is unknown , but an understanding seems likely to hold a clue to accretion conditions , and to the energy budget problem in particular the too - great strength of low - ionization emission lines such as feii ( netzer 1985 ) .

Suppose that you have an abstract for a scientific paper: this study investigates empirically whether the degree of stock market efficiency is related to the prediction power of future price change using the indices of twenty seven stock markets . efficiency refers to weak - form efficient market hypothesis ( emh ) in terms of the information of past price changes . the prediction power corresponds to the hit - rate , which is the rate of the consistency between the direction of actual price change and that of predicted one , calculated by the _ nearest neighbor prediction method _ ( nn method ) using the out - of - sample . in this manuscript , the _ hurst exponent _ and the _ approximate entropy _ ( apen ) are used as the quantitative measurements of the degree of efficiency . the relationship between the hurst exponent , reflecting the various time correlation property , and the apen value , reflecting the randomness in the time series , shows negative correlation ( @xmath0 where @xmath1 represents cross - correlation , @xmath2 the hurst exponent , and @xmath3 apen ) . however , the average prediction power on the direction of future price change has the strongly positive correlation with the hurst exponent ( @xmath4 where @xmath5 represents the average prediction power calculated by the nn method ) ) , and the negative correlation with the apen ( @xmath6 ) . therefore , the market index with less market efficiency has higher prediction power for future price change than one with higher market efficiency when we analyze the market using the past price change pattern . furthermore , we show that the hurst exponent , a measurement of the long - term memory property , provides more significant information in terms of prediction of future price changes than the apen and the nn method . . And you have already written the first three sentences of the full article: the efficient market hypothesis ( emh ) has significant influence on theory as well as practical business in the financial literature @xcite . various evidence concerning market efficiency has been recently discussed . also the predictability of future price change in the stock market is a very interesting area in the financial field .. Please generate the next two sentences of the article

research topics on both the degree of efficiency and predictability generally have been known to be intimately related . in a weak - form emh , a lower degree of efficiency means that the usefulness of past price change is high in terms of the prediction of future price change .

Suppose that you have an abstract for a scientific paper: long - range beam beam effects are a potential limit to the lhc performance with the nominal design parameters , and certain upgrade scenarios under discussion . to mitigate long - range effects , current carrying wires parallel to the beam were proposed and space is reserved in the lhc for such wires . two current carrying wires were installed in rhic to study the effect of strong long - range beam beam effects in a collider , as well as test the compensation of a single long - range interaction . the experimental data were used to benchmark simulations . we summarize this work . . And you have already written the first three sentences of the full article: the reader should note that this is an identical copy of an article first published in @xcite . beam effects have limited the performance of previous and existing hadron colliders @xcite such as the isr @xcite , sp@xmath0s @xcite , tevatron @xcite and rhic @xcite , and are also expected to limit the performance of the lhc @xcite . beam beam effects can be categorized as either incoherent ( dynamic aperture and beam lifetime ) , pacman ( bunch - to - bunch variations ) , or coherent ( beam oscillations and instabilities ) @xcite .. Please generate the next two sentences of the article

these effects can be caused by both head - on and long - range interactions . head - on effects , leading to tune shifts and spreads , are important in all hadron colliders .

Suppose that you have an abstract for a scientific paper: it is shown that induced raman scattering of electromagnetic waves in the strongly magnetized electron - positron plasma of pulsar magnetosphere may be important for wave propagation and as an effective saturation mechanism for electromagnetic instabilities . the frequencies , at which strong raman scattering occurs in the outer parts of magnetosphere , fall into the observed radio band . the typical threshold intensities for the strong raman scattering are of the order of the observed intensities , implying that pulsar magnetosphere may be optically thick to raman scattering of electromagnetic waves . [ [ section ] ] . And you have already written the first three sentences of the full article: we aim to estimate the effects of the the induced raman scattering of the strong electromagnetic wave propagating in pulsar magnetosphere . raman scattering may be considered as a parametric decay of the initial transverse electromagnetic wave in the another electromagnetic wave and plasma wave . the probability of this process is greatly enhanced if there many waves present in the final states .. Please generate the next two sentences of the article

this is induced raman scattering . another type of induced scattering - induced brullion scattering , i.e. the decay of the initial transverse electromagnetic wave in the another electromagnetic wave and ion sound is prohibited in electron - positron plasma , since pair plasma does not support low frequency , density perturbing waves ( like ion sound wave in electron - ion plasma ) .

Suppose that you have an abstract for a scientific paper: recent results demonstrating the chaotic behavior of geodesics in non - homogeneous vacuum _ pp_-wave solutions are generalized . here we concentrate on motion in non - homogeneous sandwich _ pp_-waves and show that chaos smears as the duration of these gravitational waves is reduced . as the number of radial bounces of any geodesic decreases , the outcome channels to infinity become fuzzy , and thus the fractal structure of the initial conditions characterizing chaos is cut at lower and lower levels . in the limit of impulsive waves , the motion is fully non - chaotic . this is proved by presenting the geodesics in a simple explicit form which permits a physical interpretation , and demonstrates the focusing effect . it is shown that a circle of test particles is deformed by the impulse into a family of closed hypotrochoidal curves in the transversal plane . these are deformed in the longitudinal direction in such a way that a specific closed caustic surface is formed . = -1.3 cm = -2.5 cm pacs numbers : 04.20.jb ; 04.30.-w ; 05.45.+b ; 95.10.fh keywords : _ pp_-waves , chaotic motion , impulsive gravitational waves . And you have already written the first three sentences of the full article: the widely known class of plane - fronted gravitational waves with parallel rays ( _ pp_-waves ) has become a paradigm of exact radiative spacetimes in general relativity . found by brinkmann in 1923 @xcite and later rediscovered independently by several authors , it has been studied for decades . the metric of vacuum _. Please generate the next two sentences of the article

pp_-waves can be written in the standard form @xcite @xmath0 where @xmath1 is an arbitrary function of the retarded time @xmath2 and the complex coordinate @xmath3 spanning the plane wave surfaces @xmath4 const . when @xmath5 is linear in @xmath3 , the metric ( [ e1 ] ) represents minkowski universe since the only non - trivial components of the curvature tensor are proportional to @xmath6 . thus the simplest case for which ( [ e1 ] ) describes gravitational waves arises for @xmath7 , where an arbitrary function @xmath8 characterizes the ` profile ' of the wave .

Suppose that you have an abstract for a scientific paper: i describe a possible scenario for the origin of proton mass in terms of cheshire cat , half - skyrmions , topology change and interplay between hidden chiral - scale symmetry and induced local symmetry . this differs from the standard constituent - quark scenario . as the baryonic matter density is increased toward the vector manifestation ( vm ) fixed - point at which the @xmath0 mass is to vanish , the effective in - medium mass ratio @xmath1 is to tend to zero proportionally to @xmath2 where @xmath2 is the in - medium hidden gauge coupling constant . i develop the thesis that the intricacy involved in the mass generation could be decoded from experiments at rib accelerators and massive compact stars . . And you have already written the first three sentences of the full article: where the proton ( or generally nucleon ) mass comes from remains , even after the discovery of higgs boson , as one of the great mysteries of nature . in this note i explore the possibility that the answer could perhaps be found in nuclear physics . given that the mass of the proton is very accurately measured , @xmath3 mev , more than 99.9% of the visible " mass around us all the way down to atoms can be accounted for in great accuracy by adding the number of nucleons involved in the system .. Please generate the next two sentences of the article

even that of the nucleus which is in the core of atoms is accounted for up to 98% . the strong interactions taking place inside the nucleus are now quantitatively described by quantum chromodynamics ( qcd ) .

Suppose that you have an abstract for a scientific paper: we have analyzed the validity of uncertainty relations between the fluctuations of thermodynamically conjugated extensive and intensive variables within the field of statistical mechanics . analysis is presented for two particular examples of small lattice systems that are in contact with reservoirs of comparable sizes : an ising paramagnet and an ising ferromagnet . the numerical results enable determination of the range of applicablity of the proposed relations . due to the fact that the examples correspond to systems described by discrete variables , the uncertainty relations are not valid if the probability of boundary states is too high . . And you have already written the first three sentences of the full article: uncertainty relations can be established in any physical theory involving random conjugated variables characterized by probability distribution functions . the present paper deals with uncertainty relations in statistical mechanics . statistical mechanics combines equilibrium thermodynamics with a probability postulate @xcite . following the standard gibbs ensemble theory , in the microcanonical ensemble it is assumed that all mechanical variables are constrained to a fixed value ( or are allowed to vary within a fixed small range ) , while their entropy - conjugated variables are free to fluctuate . other ensembles ( canonical , grand - canonical , ... ) are introduced by relaxing the constraint on one or more mechanical variables .. Please generate the next two sentences of the article

this is done by assuming that these mechanical variables can be exchanged with a reservoir , which is defined as a macroscopic body of dimensions much larger than those of the system . the exchange is supposed to be controlled by parameters ( which are characteristic of the reservoir ) that are identified as intensive variables .

Suppose that you have an abstract for a scientific paper: in this poster contribution we highlight the equivalence between an imaging air cherenkov telescope ( iact ) array and an intensity interferometer for a range of technical requirements . we touch on the differences between a michelson and an intensity interferometer and give a brief overview of the current iact arrays , their upgrades and next generation concepts ( cta , agis , completion 2015 ) . the latter are foreseen to include 30 - 90 telescopes that will provide 400 - 4000 different baselines that range in length between 50 m and a kilometre . intensity interferometry with such arrays of telescopes attains 50@xmath0-arcseconds resolution for a limiting @xmath1 . this technique opens the possibility of a wide range of studies , amongst others , probing the stellar surface activity and the dynamic au scale circumstellar environment of stars in various crucial evolutionary stages . here we discuss possibilities for using iact arrays as optical intensity interferometers . . And you have already written the first three sentences of the full article: over the past decade , michelson stellar interferometry has seen some tremendous advances in applicability . it has evolved from a primarily experimental technique towards a general astrophysical observational mode extensively used by the community for galactic and extragalactic science ( see the various contributions in these proceedings ) . observations with milli arcseconds angular resolution are now routinely performed in the near infrared .. Please generate the next two sentences of the article

strategic planning of next generation michelson interferometers should aim for higher resolution , higher sensitivity and image reconstruction capabilities ( synthesis or direct imaging ) . an alternative technique to michelson interferometry that has the potential of delivering similar scientific products is the technique of intensity interferometry ( ii ) .

Suppose that you have an abstract for a scientific paper: more than ten years ago a first step towards quantum error correction ( qec ) was implemented [ phys . rev . lett . 81 , 2152 ( 1998 ) ] . the work showed there was sufficient control in nuclear magnetic resonance ( nmr ) to implement qec , and demonstrated that the error rate changed from @xmath0 to approximatively @xmath1 . in the current work we reproduce a similar experiment using control techniques that have been since developed , such as grape pulses . we show that the fidelity of the qec gate sequence , and the comparative advantage of qec are appreciably improved . this advantage is maintained despite the errors introduced by the additional operations needed to protect the quantum states . . And you have already written the first three sentences of the full article: quantum computers could solve some problems faster than classical computers @xcite . performing a quantum computation relies on the ability to preserve the coherence of quantum states long enough for gates composing the algorithm to be implemented . in practice , the quantum coherence is sensitive to the uncontrolled environment and easily damaged by the interactions with the environment , a process called decoherence @xcite . to protect the fragile quantum coherence needed for quantum computation , schemes of quantum error correction ( qec ) and fault- tolerant quantum computation have been developed @xcite .. Please generate the next two sentences of the article

the 3-bit qec code was implemented in a liquid - state nmr quantum information processor in 1998 as the first experimental demonstration of qec @xcite . more recently , it has been implemented in trapped ion and solid - state systems @xcite . here

Suppose that you have an abstract for a scientific paper: optical microscopy is one of the oldest scientific instruments that is still used in forefront research . ernst abbe s nineteenth century formulation of the resolution limit in microscopy let generations of scientists believe that optical studies of individual molecules and resolving sub - wavelength structures were not feasible . the nobel prize in 2014 for super - resolution fluorescence microscopy marks a clear recognition that the old beliefs have to be revisited . in this article , we present a critical overview of various recent developments in optical microscopy . in addition to the popular super - resolution fluorescence methods , we discuss the prospects of various other techniques and imaging contrasts and consider some of the fundamental and practical challenges that lie ahead . [ 1995/12/01 ] . And you have already written the first three sentences of the full article: the first compound light microscopes constructed in the 16th and 17th centuries enabled scientists to inspect matter and biological specimens at the microscopic level @xcite . in 1873 , ernst abbe formulated a fundamental limit for the resolution of an optical imaging system based on the diffraction theory of light @xcite . at the same time the fabrication and development of microscopes and lenses were transformed from empirical optimizations to schemes based on quantitative calculations and theoretical considerations . in the 20th century various contrast modalities were developed that allow one to detect very small signals and to measure characteristic properties of a specimen with high specificity . finally , during the last two decades several revolutionary methods were conceived and experimentally demonstrated , which substantially enhanced the optical resolution down to the nanometer scale ( shown in fig . [ fig_opticalresolution ] ) .. Please generate the next two sentences of the article

the awarding of the 2014 nobel prize in chemistry to eric betzig , stefan hell and william e. moerner for their pioneering work in `` super - resolution '' fluorescence microscopy corroborates its promise for many advanced investigations in physics , chemistry , materials science and life sciences . fluorescence microscopy down to the single molecule level has been reviewed in many recent articles and books @xcite . despite the immense success of fluorescence microscopy

Suppose that you have an abstract for a scientific paper: a nematic quantum critical point is anticipated to exist in the superconducting dome of some high - temperature superconductors . the nematic order competes with the superconducting order and hence reduces the superconducting condensate at @xmath0 . moreover , the critical fluctuations of nematic order can excite more nodal quasiparticles out of the condensate . we address these two effects within an effective field theory and show that superfluid density @xmath1 and superconducting temperature @xmath2 are both suppressed strongly by the critical fluctuations . the strong suppression of superconductivity provides a possible way to determine the nematic quantum critical point . . And you have already written the first three sentences of the full article: the strong electron correlation in high - temperature superconductors ( htsc ) is able to drive an electronic nematic phase @xcite , which preserves translational symmetry but breaks rotational symmetry . in the past decade , there have been a number of experimental signatures pointing to the presence of nematic ordering transition in some htscs @xcite . on the basis of these experiments , a zero - temperature nematic quantum critical point ( qcp ) is supposed to exist at certain doping concentration @xmath3 in the superconducting ( sc ) dome @xcite . generally , the nematic order has two impacts on the sc state . first , it competes with the sc order @xcite .. Please generate the next two sentences of the article

second , the nematic order parameter couples to the gapless nodal quasiparticles ( qps ) , which are believed to be the most important fermionic excitations in unconventional superconductors with @xmath4 energy gap . the latter coupling is singular at the nematic qcp @xmath3 , and has stimulated considerable theoretical efforts @xcite .

Suppose that you have an abstract for a scientific paper: we combine new high sensitivity ultraviolet ( uv ) imaging from the wide field camera 3 ( wfc3 ) on the hubble space telescope ( hst ) with existing deep hst / advanced camera for surveys ( acs ) optical images from the great observatories origins deep survey ( goods ) program to identify uv - dropouts , which are lyman break galaxy ( lbg ) candidates at @xmath0 . these new hst / wfc3 observations were taken over 50 arcmin@xmath1 in the goods - south field as a part of the early release science program . the uniqueness of these new uv data is that they are observed in 3 uv / optical ( wfc3 uvis ) channel filters ( f225w , f275w and f336w ) , which allows us to identify three different sets of uv - dropout samples . we apply lyman break dropout selection criteria to identify f225w- , f275w- and f336w - dropouts , which are @xmath2 , @xmath3 and @xmath4 lbg candidates , respectively . we use multi - wavelength imaging combined with available spectroscopic and photometric redshifts to carefully access the validity of our uv - dropout candidates . our results are as follows : ( 1 ) these wfc3 uvis filters are very reliable in selecting lbgs with @xmath5 , which helps to reduce the gap between the well studied @xmath6 and @xmath7 regimes ; ( 2 ) the combined number counts with average redshift @xmath8 agrees very well with the observed change in the surface densities as a function of redshift when compared with the higher redshift lbg samples ; and ( 3 ) the best - fit schechter function parameters from the rest - frame uv luminosity functions at three different redshifts fit very well with the evolutionary trend of the characteristic absolute magnitude , @xmath9 , and the faint - end slope , @xmath10 , as a function of redshift . this is the first study to illustrate the usefulness of the wfc3 uvis channel observations to select @xmath11 lbgs . the addition of the new wfc3 on the hst has made it possible to uniformly select lbgs from @xmath12 to @xmath13 , and significantly enhance our.... And you have already written the first three sentences of the full article: the lyman break ` dropout ' technique was first applied to select lyman break galaxies ( lbgs ) at @xmath14 @xcite , and since then it has been extensively used to select lbg candidates at @xmath15 ( e.g. , * ? ? ? * ; * ? ? ? * ; * ? ? ?. Please generate the next two sentences of the article

* ; * ? ? ? * ; * ? ? ?