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Suppose that you have an abstract for a scientific paper: mnge has been grown as a thin film on si(111 ) substrates by molecular beam epitaxy . a 10 layer of mnsi was used as seedlayer in order to establish the b20 crystal structure . films of a thickness between 45 and 135 have been prepared and structually characterized by rheed , afm and xrd . these techniques give evidence that mnge forms in the cubic b20 crystal structure as islands exhibiting a very smooth surface . the islands become larger with increasing film thickness . a magnetic characterization reveals that the ordering temperature of mnge thin films is enhanced compared to bulk material . the properties of the helical magnetic structure obtained from magnetization and magnetoresistivity measurements are compared with films of the related compound mnsi . the much larger dzyaloshinskii - moriya interaction in mnge results in a higher rigidness of the spin helix . . And you have already written the first three sentences of the full article: the experimental evidence of the theoretically predicted skyrmions in non - centrosymmetric compounds with dzyloshinskii - moriya interaction has intrigued many scientists over the last years.@xcite recently , the preparation of thin films of b20 type mnsi on silicon substrates @xcite has offered promising prospects with regard to possible applications in future spintronic devices . on the one hand mnsi films offer a variety of interesting magnetic phases and on the other hand they are easy to integrate into devices due to the use of silicon as substrate material being well established in technology . the benefit of thin films compared to bulk material is the existence of the skyrmion phase in an extended region of the magnetic phase diagram due to the uniaxial anisotropy.@xcite this pioneers new opportunities for data storage devices .. Please generate the next two sentences of the article

the drawback using mnsi films is the low magnetic ordering temperature , which is considerably below liquid nitrogen temperature . therefore , it is the aim to find compounds with similar spin order at higher temperatures .

Suppose that you have an abstract for a scientific paper: we introduce a family of piecewise isometries @xmath0 parametrized by @xmath1 on the surface of a regular tetrahedron , which we call the tetrahedral twists . this family of maps is similar to the pets constructed by patrick hooper . we study the dynamics of the tetrahedral twists through the notion of renormalization . by the assistance of computer , we conjecture that the renormalization scheme exists on the entire interval @xmath2 . in this paper , we show that this system is renormalizable in the subintervals @xmath3 $ ] and @xmath4 . . And you have already written the first three sentences of the full article: piecewise isometries have rich dynamical phenomena and they sometimes produce fractal - like pictures . to define these maps , let @xmath5 be a subset of @xmath6 with a finite partition @xmath7 . a piecewise isometry @xmath8 is a map such that the restriction of @xmath9 to each @xmath10 is a euclidean isometry .. Please generate the next two sentences of the article

the map is not defined on the boundaries @xmath11 for @xmath12 . in this paper , we introduce a one - parameter family of piecewise isometries called the _

Suppose that you have an abstract for a scientific paper: we provide an overview on superstatistical techniques applied to complex systems with time scale separation . three examples of recent applications are dealt with in somewhat more detail : the statistics of small - scale velocity differences in lagrangian turbulence experiments , train delay statistics on the british rail network , and survival statistics of cancer patients once diagnosed with cancer . these examples correspond to three different universality classes : lognormal superstatistics , @xmath0-superstatistics and inverse @xmath0 superstatistics . . And you have already written the first three sentences of the full article: many complex systems in various areas of science exhibit a spatio - temporal dynamics that is inhomogeneous and can be effectively described by a superposition of several statistics on different scales , in short a superstatistics @xcite . the superstatistics notion was introduced in @xcite , in the mean time many applications for a variety of complex systems have been pointed out @xcite . essential for this approach is the existence of sufficient time scale separation between two relevant dynamics within the complex system .. Please generate the next two sentences of the article

there is an intensive parameter @xmath1 that fluctuates on a much larger time scale than the typical relaxation time of the local dynamics . in a thermodynamic setting , @xmath1 can be interpreted as a local inverse temperature of the system , but much broader interpretations are possible .

Suppose that you have an abstract for a scientific paper: we estimate the neutrino emission from individual gamma - ray bursts observed by the batse detector on the compton gamma - ray observatory . neutrinos are produced by photoproduction of pions when protons interact with photons in the region where the kinetic energy of the relativistic fireball is dissipated allowing the acceleration of electrons and protons . we also consider models where neutrinos are predominantly produced on the radiation surrounding the newly formed black hole . from the observed redshift and photon flux of each individual burst , we compute the neutrino flux in a variety of models based on the assumption that equal kinetic energy is dissipated into electrons and protons . where not measured , the redshift is estimated by other methods . unlike previous calculations of the universal diffuse neutrino flux produced by all gamma - ray bursts , the individual fluxes ( compiled at http://www.arcetri.astro.it/@xmath0 dafne / grb/ ) can be directly compared with coincident observations by the amanda telescope at the south pole . because of its large statistics , our predictions are likely to be representative for future observations with larger neutrino telescopes . . And you have already written the first three sentences of the full article: the leading models for gamma - ray bursts ( grb ) , bursts of 0.1 - 1 mev photons typically lasting for 0.1 - 100 seconds ( fishman & meegan 1995 ) , involve a relativistic wind emanating from a compact central source . the ultimate energy source is rapid accretion onto a newly formed stellar mass black hole . observations suggest that the prompt @xmath1-ray emission is produced by the dissipation ( perhaps due to internal shocks ) of the kinetic energy of a relativistically expanding wind , i.e. a `` fireball '' .. Please generate the next two sentences of the article

both synchrotron and inverse compton emissions from the shock - accelerated electrons have been proposed as the grb emission mechanism . in this paper , we study in detail the production of neutrinos by protons accelerated along with electrons . we assume that equal energy of the fireball is dissipated in protons and electrons ( or photons ) .

Suppose that you have an abstract for a scientific paper: this paper is motivated by the fact that many systems need to be maintained continually while the underlying costs change over time . the challenge then is to continually maintain near - optimal solutions to the underlying optimization problems , without creating too much churn in the solution itself . we model this as a multistage combinatorial optimization problem where the input is a sequence of cost functions ( one for each time step ) ; while we can change the solution from step to step , we incur an additional cost for every such change . we first study the multistage matroid maintenance problem , where we need to maintain a base of a matroid in each time step under the changing cost functions and acquisition costs for adding new elements . the online version of this problem generalizes onine paging , and is a well - structured case of the metrical task systems . e.g. , given a graph , we need to maintain a spanning tree @xmath0 at each step : we pay @xmath1 for the cost of the tree at time @xmath2 , and also @xmath3 for the number of edges changed at this step . our main result is a polynomial time @xmath4-approximation to the online multistage matroid maintenance problem , where @xmath5 is the number of elements / edges and @xmath6 is the rank of the matroid . this improves on results of buchbinder et al . @xcite who addressed the _ fractional _ version of this problem under uniform acquisition costs , and buchbinder , chen and naor @xcite who studied the fractional version of a more general problem . we also give an @xmath7 approximation for the offline version of the problem . these bounds hold when the acquisition costs are non - uniform , in which case both these results are the best possible unless p = np . we also study the perfect matching version of the problem , where we must maintain a perfect matching at each step under changing cost functions and costs for adding new elements . surprisingly , the hardness drastically increases : for any constant @xmath8 ,.... And you have already written the first three sentences of the full article: in a typical instance of a combinatorial optimization problem the underlying constraints model a static application frozen in one time step . in many applications however , one needs to solve instances of the combinatorial optimization problem that changes over time . while this is naturally handled by re - solving the optimization problem in each time step separately , changing the solution one holds from one time step to the next often incurs a transition cost . consider , for example , the problem faced by a vendor who needs to get supply of an item from @xmath10 different producers to meet her demand . on any given day. Please generate the next two sentences of the article

, she could get prices from each of the producers and pick the @xmath10 cheapest ones to buy from . as prices change , this set of the @xmath10 cheapest producers may change .

Suppose that you have an abstract for a scientific paper: we are interested in electrons kinetics in a stellar atmosphere to validate or invalidate the usually accepted hypothesis of thermalisation of electrons . for this purpose , we calculate the velocity distribution function of electrons by solving the kinetic equation of these particles together with the equations of radiative transfer and statistical equilibrium . we note that this distribution can deviate strongly from a maxwell - boltzmann distribution if non - lte effects are important . some results and astrophysical consequences are examined . . And you have already written the first three sentences of the full article: our work is concerned with the kinetics of electrons in a stellar atmosphere , modelled as a parallel - plane slab irradiated on a face . our models of atmospheres start in the deep layers of stars , where the radiative field can be described in the diffusion approximation , and end with the layers of minimal temperature , before the chromospheric raise whose effects are ignored . the free electrons are characterized by their velocity distribution function : the electron distribution function ( edf ) , which is calculated with the other thermodynamical quantities of the atmosphere . our main objective is to understand the mechanism leading to the thermalisation of electrons , where the edf tends toward the maxwell - boltzmann distribution .. Please generate the next two sentences of the article

it is accepted , in stellar atmospheres theory , that the thermalisation of electrons is effective as long as elastic collisions dominate inelastic interactions of electrons with the plasma , a rather well verified hypothesis for electrons having energies greatly below the first excitation energies of atoms and ions composing the atmosphere . this hypothesis is not necessarily correct for faster electrons .

Suppose that you have an abstract for a scientific paper: we point out that a non - overlapping well ( at negative energies ) adjacent to a finite barrier ( at positive energies ) is a simple potential which is generally missed out while discussing the one - dimensional potentials in the textbooks of quantum mechanics . we show that these systems present interesting situations wherein transmitivity @xmath0 of a finite barrier can be changed both quantitatively and qualitatively by varying the depth or width of the well or by changing the distance between the well and the barrier . using delta ( thin ) well near a delta ( thin ) barrier we show that the well induces energy oscillations riding over @xmath1 in the transmitivity @xmath2 at both the energies below and above the barrier . more generally we show that a thick well separated from a thick barrier also gives rise to energy oscillations in @xmath2 . a well joining a barrier discontinuously ( a finite jump ) reduces @xmath2 ( as compared to @xmath3 over all energies . when the well and barrier are joined continuously , @xmath2 increases and then decreases at energies below the barrier . at energy above the the barrier the changes are inappreciable . in these two cases if we separate the well and the barrier by a distance , @xmath2 again acquires oscillations . paradoxically , it turns out that a distant well induces more energy oscillations in @xmath2 than when it is near the barrier . . And you have already written the first three sentences of the full article: in the textbooks of quantum mechanics the solution of schrdinger equation and the consequent results are illustrated through simple one - dimensional potentials . for discrete bound states the square well@xcite and double wells@xcite are studied . square well , square barrier and semi - infinite step potentials are used for studying continuous energy ( scattering ) states.@xcite a well with two side barriers is studied for understanding resonances and meta - stable states.@xcite an overlapping well adjacent to a finite barrier is a well known model for discussing discrete complex energy gamow - seigert meta - stable states @xcite in alpha decay . students may wonder as to what happens if a non - overlapping well ( at negative energies ) is adjacent to a finite barrier ( at negative energies ) ( see figs . 1 ) . perhaps for the want of an application this system has gone undiscussed , however , interesting queries do arise for this kind of potentials. Please generate the next two sentences of the article

. one may wonder as to whether the well ( at negative energies ) can change ( increase / decrease ) the transmitivity of the barrier ( at positive energies ) quantitatively and significantly . one may like to know whether there can be qualitative changes in the transmitivity of the barrier @xmath0 due to the presence of the well in some class of cases . in this article we would like to show that a well near a barrier can change the transmitivity of the barrier both quantitatively and qualitatively .

Suppose that you have an abstract for a scientific paper: it has been hypothesized recently that core collapse supernovae are triggered by mildly relativistic jets following observations of radio properties of these explosions . association of a jet , similar to a gamma - ray burst jet but only slower , allows shock acceleration of particles to high energy and non - thermal neutrino emission from a supernova . detection of these high energy neutrinos in upcoming kilometer scale cherenkov detectors may be the only direct way to probe inside these astrophysical phenomena as electromagnetic radiation is thermal and contains little information . calculation of high energy neutrino signal from a simple and slow jet model buried inside the pre - supernova star is reviewed here . the detection prospect of these neutrinos in water or ice detector is also discussed in this brief review . jetted core collapse supernovae in nearby galaxies may provide the strongest high energy neutrino signal from point sources . . And you have already written the first three sentences of the full article: core collapse of massive stars which lead to supernovae ( sne ) of type ib , c and ii are in some cases associated with long duration ( @xmath0-@xmath1 s ) gamma - ray bursts ( grbs ) , as evidenced by observed correlations of grb 980425/sn 1998bw , grb 021211/sn 2002lt , grb 030329/sn 2003dh and grb 0131203/sn 2003lw.@xcite a relativistic jet with bulk lorentz factor @xmath2 , powered by a black hole and an accretion disc which form after the core collapse in the most likely scenario , is believed to lead to the grb event.@xcite observational evidence of only a small fraction of detected sne associated with grbs hints that the frequency of highly relativistic jets in core collapse sne is at best 1 in 1000 , roughly the ratio of grb to sn rates.@xcite however , a significantly larger fraction ( @xmath3 of type ib / c rate@xcite ) of sne ( also called _ hypernovae _ ) may have mildly relativistic jets associated with them.@xcite one or more of the following observations support the jetted sn hypothesis : high expansion velocity ( 30 - 40 @xmath4 km / s ) first observed in sn 1998bw.@xcite radio afterglow not associated with @xmath5-ray emission.@xcite asymmetric explosion supported by polarimetry observations of sn type ib / c.@xcite numerical simulations of core collapse sne , carried out over the last three decades have failed to produce a successful explosion by a prompt shock wave created due to the collapse of its iron core.@xcite the deposition of bulk kinetic energy in a jet form into the stellar envelope may help disrupt and blow it up making the sn possible.@xcite the presence of a jet is also conducive to shock acceleration of particles . in case of a grb , internal shocks of plasma material along the jet accelerate protons and electrons which radiate observed @xmath5-rays.@xcite high energy protons may escape as cosmic rays and/or produce 100 tev neutrinos by interacting with @xmath5-rays _ in situ_.@xcite while the grb jet is making its way out of the collapsing stellar progenitor it is.... Please generate the next two sentences of the article

kilometer scale ice and water cherenkov detectors such as icecube@xcite and antares@xcite which are currently being built in antarctica and in the mediterranean will have an excellent chance to detect these neutrinos from sne within the nearest 20 mpc . the organization of this brief review is as follows : in sec .

Suppose that you have an abstract for a scientific paper: we determine the intrinsic , 3-dimensional shape distribution of star - forming galaxies at @xmath0 , as inferred from their observed projected axis ratios . in the present - day universe star - forming galaxies of all masses @xmath1 are predominantly thin , nearly oblate disks , in line with previous studies . we now extend this to higher redshifts , and find that among massive galaxies ( @xmath2 ) disks are the most common geometric shape at all @xmath3 . lower - mass galaxies at @xmath4 possess a broad range of geometric shapes : the fraction of elongated ( prolate ) galaxies increases toward higher redshifts and lower masses . galaxies with stellar mass @xmath5 ( @xmath6 ) are a mix of roughly equal numbers of elongated and disk galaxies at @xmath7 ( @xmath8 ) . this suggests that galaxies in this mass range do not yet have disks that are sustained over many orbital periods , implying that galaxies with present - day stellar mass comparable to that of the milky way typically first formed such sustained stellar disks at redshift @xmath9 . combined with constraints on the evolution of the star formation rate density and the distribution of star formation over galaxies with different masses , our findings imply that , averaged over cosmic time , the majority of stars formed in disks . . And you have already written the first three sentences of the full article: the shape of the stellar body of a galaxy reflects its formation process . reconstructing the intrinsic , three - dimensional shapes of spiral galaxies from their shapes projected on the sky has a long tradition , and proved to be an exquisitely accurate and precise approach , especially once sample size increased ( e.g. , * ? ? ? * ; * ? ? ?. Please generate the next two sentences of the article

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

Suppose that you have an abstract for a scientific paper: we examine the relationship between dependence logic and game logics . a variant of dynamic game logic , called _ transition logic _ , is developed , and we show that its relationship with dependence logic is comparable to the one between first - order logic and dynamic game logic discussed by van benthem . this suggests a new perspective on the interpretation of dependence logic formulas , in terms of assertions about _ reachability _ in games of imperfect information against nature . we then capitalize on this intuition by developing expressively equivalent variants of dependence logic in which this interpretation is taken to the foreground . . And you have already written the first three sentences of the full article: dependence logic @xcite is an extension of first - order logic which adds _ dependence atoms _ of the form @xmath0 to it , with the intended interpretation of `` the value of the term @xmath1 is a function of the values of the terms @xmath2 . '' the introduction of such atoms is roughly equivalent to the introduction of non - linear patterns of dependence and independence between variables of branching quantifier logic @xcite or independence friendly logic @xcite : for example , both the branching quantifier logic sentence @xmath3 and the independence friendly logic sentence @xmath4 correspond in dependence logic to @xmath5 in the sense that all of these expressions are equivalent to the skolem formula @xmath6 as this example illustrates , the main peculiarity of dependence logic compared to the others above - mentioned logics lies in the fact that , in dependence logic , the notion of _ dependence and independence between variables _ is explicitly separated from the notion of quantification . this makes it an eminently suitable formalism for the formal analysis of the properties of _ dependence itself _ in a first - order setting , and some recent papers ( @xcite ) explore the effects of replace dependence atoms with other similar primitives such as _ independence atoms _ @xcite , _ multivalued dependence atoms _. Please generate the next two sentences of the article

@xcite , or _ inclusion _ or _ atoms @xcite .

Suppose that you have an abstract for a scientific paper: we present and discuss a variance - reduced stochastic particle method for simulating the relaxation - time model of the boltzmann transport equation . the present paper focuses on the dilute gas case , although the method is expected to directly extend to all fields ( carriers ) for which the relaxation - time approximation is reasonable . the variance reduction , achieved by simulating only the deviation from equilibrium , results in a significant computational efficiency advantage compared to traditional stochastic particle methods in the limit of small deviation from equilibrium . more specifically , the proposed method can efficiently simulate arbitrarily small deviations from equilibrium at a computational cost that is independent of the deviation from equilibrium , which is in sharp contrast to traditional particle methods . the boltzmann transport equation @xmath0 _ { \textrm{coll}}}}\ ] ] where @xmath1 is the single - particle distribution function @xcite , @xmath2 _ { \textrm{coll}}}}$ ] denotes the collision operator , @xmath3 is the acceleration due to an external field , @xmath4 is the position vector in physical space , @xmath5 is the molecular velocity vector , and @xmath6 is time , is used to describe ( under appropriate conditions ) transport processes in a wide variety of fields @xcite including dilute gas flow @xcite , phonon @xcite , electron @xcite , neutron @xcite and photon transport @xcite . recently , it has received renewed attention in connection to micro- and nano - scale science and technology where transport at lengthscales of the order of , or smaller than , the carrier mean free path is frequently considered ( e.g. nanoscale solid - state heat transfer @xcite ) numerical solution of the boltzmann equation remains a formidable task due to the complexity associated with the collision operator and the high dimensionality of the distribution function . both these features have contributed to the prevalence of particle solution methods , which are typically able to.... And you have already written the first three sentences of the full article: this work was supported by the singapore - mit alliance under the hpces program . 10 c. cercignani , _ the boltzmann equation and its applications _ , springer - verlag , new york , 1988 . g. chen , _ nanoscale energy transport and conversion _ , oxford , new york , 2005 . v.. Please generate the next two sentences of the article

l. gurevich , _ transport in phonon systems _ , north - holland , new york , 1986 . m. lundstrom , _ fundamentals of carrier transport _ , 2nd ed . , cambridge university press , cambridge , 2000 .

Suppose that you have an abstract for a scientific paper: in this work we study thermal leptogenesis using non - equilibrium quantum field theory . starting from fundamental equations for correlators of the quantum fields we describe the steps necessary to obtain quantum kinetic equations for quasiparticles . these can easily be compared to conventional results and overcome conceptional problems inherent in the canonical approach . beyond _ cp_-violating decays we include also those scattering processes which are tightly related to the decays in a consistent approximation of fourth order in the yukawa couplings . it is demonstrated explicitly how the s - matrix elements for the scattering processes in the conventional approach are related to two- and three - loop contributions to the effective action . we derive effective decay and scattering amplitudes taking medium corrections and thermal masses into account . in this context we also investigate _ cp_-violating higgs decay within the same formalism . from the kinetic equations we derive rate equations for the lepton asymmetry improved in that they include quantum - statistical effects and medium corrections to the quasiparticle properties . . And you have already written the first three sentences of the full article: if one combines today s standard model of particle physics ( sm ) and that of cosmology , one finds inevitably that particles and their antiparticles annihilate at a very early moment in the evolution of the universe , leaving just radiation behind . the absence of a sizable matter - antimatter asymmetry at this epoch would imply that the universe as we know it could never form . the question about the origin of the observed asymmetry therefore represents a major challenge for modern physics . in the sm baryon and lepton number. Please generate the next two sentences of the article

are ( accidental ) global symmetries . if baryon number was also conserved in the early universe a dynamical emergence of the asymmetry would have been impossible . in grand - unified extensions ( guts ) of the sm baryon number ( and also lepton number )

Suppose that you have an abstract for a scientific paper: here we report on the translocation of folded polymers through nano - pores using molecular dynamic simulations . two cases are studied ; one in which a folded molecule unfolds upon passage and one in which the folding remains intact as the molecule passes through the nano - pore . the topology of a folded polymer chain is defined as the arrangement of the intramolecular contacts , known as circuit topology . in the case where intramolecular contacts remain intact , we show that the dynamics of passage through a nano - pore varies for molecules with differing topologies : a phenomenon that can be exploited to enrich certain topologies in mixtures . we find that the nano - pore allows reading of topology for short chains . moreover , when the passage is coupled with unfolding , the nano - pore enables discrimination between pure states , i.e. , states for which the majority of contacts are arranged identically . in this case , as we show here , it is also possible to read the positions of the contact sites along a chain . our results demonstrate the applicability of nano - pore technology to characterize and sort molecules based on their topology . . And you have already written the first three sentences of the full article: most biopolymers , such as rnas @xcite , proteins @xcite and genomic dna @xcite , are found in folded configurations . folding involves the formation of one or more intramolecular interactions , termed contacts . proper folding of these molecules is often necessary for their function .. Please generate the next two sentences of the article

intensive efforts have been made to measure the geometric and topological properties of protein and rna folds , and to find generic relations between those properties and molecular function , dynamics and evolution @xcite . likewise , topological properties of synthetic molecules have been subject to intense research , and their significance for polymer chemistry @xcite and physics @xcite has been widely recognized .

Suppose that you have an abstract for a scientific paper: measurements of small - scale turbulent fluctuations in the solar wind find a non - zero right - handed magnetic helicity . this has been interpreted as evidence for ion cyclotron damping . however , theoretical and empirical evidence suggests that the majority of the energy in solar wind turbulence resides in low frequency anisotropic kinetic alfvn wave fluctuations that are not subject to ion cyclotron damping . we demonstrate that a dissipation range comprised of kinetic alfvn waves also produces a net right - handed fluctuating magnetic helicity signature consistent with observations . thus , the observed magnetic helicity signature does not necessarily imply that ion cyclotron damping is energetically important in the solar wind . . And you have already written the first three sentences of the full article: the identification of the physical mechanisms responsible for the dissipation of turbulence in the solar wind , and for the resulting heating of the solar wind plasma , remains an important and unsolved problem of heliospheric physics . an important clue to this problem is the observed non - zero fluctuating magnetic helicity signature at scales corresponding to the dissipation range of solar wind turbulence . @xcite first proposed the `` fluctuating '' magnetic helicity as a diagnostic of solar wind turbulence , defining the `` reduced fluctuating '' magnetic helicity spectrum derivable from observational data ( see [ sec : red ] below ) . a subsequent study. Please generate the next two sentences of the article

, corresponding to scales within the inertial range , found values that fluctuated randomly in sign , and suggested an interpretation that `` a substantial degree of helicity or circular polarization exists throughout the wavenumber spectrum , but the sense of polarization or handedness alternates randomly '' @xcite . based on a study of the fluctuating magnetic helicity of solutions to the linear vlasov - maxwell dispersion relation , @xcite suggested instead that , at inertial range scales , all eigenmodes have a very small _ intrinsic _ normalized fluctuating magnetic helicity , eliminating the need to invoke an ensemble of waves with both left- and right - handed helicity to explain the observations .

Suppose that you have an abstract for a scientific paper: the phase behavior of asymmetrically interacting abc star triblock copolymer melts is investigated by the self - consistent field theory ( scft ) . motivated by the experimental systems , in this study , we focus on the systems in which the flory - huggins interaction parameters satisfy @xmath0 . using various initialization strategies , a large number of periodic structures have been obtained in our calculations . a fourth - order pseudospectral algorithm combined with anderson mixing method is used to compute the free energy of candidate structures carefully . the stability has been detailedly analyzed by splitting the free energy into internal and entropic parts . a complete and complex triangular phase diagram is presented for a model with @xmath1 in which fifteen ordered phases , including two- , and three - dimensional structures , have been predicted to be stable from the scft calculations . generally speaking , with the asymmetrical interactions , the hierarchical structures tend to be formed near the b - rich corner of the triangular phase diagram . this work broadens the previous theoretical results from equal interaction systems to unequal interaction systems . the predicted phase behavior is in good agreement with experimental observations and previous theoretical results . . And you have already written the first three sentences of the full article: block copolymers , constructed by linking together chemically distinct subchains or blocks , spontaneously assemble into exquisitely ordered soft materials@xcite . the self - assembled order structures , spanning length scales from a few nanometers to several micrometers , offer a diverse and expanding range of practical applications in , for example , optical materials , microelectronic materials , drug delivery , advanced plastics , and nanotemplates@xcite . the development of nanotechnology using block copolymers requires a good understanding of the phase behavior of the block copolymers . the self - assembling mechanism of block copolymers sensitively depends on block types , the number of blocks , block - block interactions , architecture , and topology of the block polymers .. Please generate the next two sentences of the article

the equilibrium ordered patterns can be formed due to the delicate balance between these competing factors . in abc triblock copolymers , the number of controlled parameters is at least five , including three interaction parameters @xmath2 , @xmath3 , @xmath4 , and two independent block compositions @xmath5 and @xmath6 .

Suppose that you have an abstract for a scientific paper: the conductance profiles of magnetic transition metal atoms , such as fe , co and mn , deposited on surfaces and probed by a scanning tunneling microscope ( stm ) , provide detailed information on the magnetic excitations of such nano - magnets . in general the profiles are symmetric with respect to the applied bias . however a set of recent experiments has shown evidence for inherent asymmetries when either a normal or a spin - polarized stm tip is used . in order to explain such asymmetries here we expand our previously developed perturbative approach to electron - spin scattering to the spin - polarized case and to the inclusion of out of equilibrium spin populations . in the case of a magnetic stm tip we demonstrate that the asymmetries are driven by the non - equilibrium occupation of the various atomic spin - levels , an effect that reminds closely that electron spin - transfer . in contrast when the tip is not spin - polarized such non - equilibrium population can not be build up . in this circumstance we propose that the asymmetry simply originates from the transition metal ion density of state , which is included here as a non - vanishing real component to the spin - scattering self - energy . . And you have already written the first three sentences of the full article: the possibility of altering and controlling the spin - state of a single magnetic ion or of a small magnetic cluster with an external probe represents a unique opportunity towards the understanding and the exploitation of the magnetic interaction at the most microscopic level . possible areas of application for such ability may include spin - based quantum logic , where one necessitates to prepare , manipulate and read spin - qubits . it is then crucial to develop tools capable of addressing the single spin - limit .. Please generate the next two sentences of the article

low - temperature scanning tunneling microscopy provides one of such tools . in general the method exploits a scanning tunneling microscope ( stm ) operated in spectroscopical mode , by which the inelastic electron tunneling spectroscopy ( iets ) at the spin - excitations of a given system is measured @xcite . this scheme is known as spin - flip iets ( sf - iets ) .

Suppose that you have an abstract for a scientific paper: the core entropy of polynomials , recently introduced by w. thurston , is a dynamical invariant which can be defined purely in combinatorial terms , and provides a useful tool to study parameter spaces of polynomials . the theory of core entropy extends to complex polynomials the entropy theory for real unimodal maps : the real segment is replaced by an invariant tree , known as hubbard tree , which lives inside the filled julia set . we prove that the core entropy of quadratic polynomials varies continuously as a function of the external angle , answering a question of thurston . . And you have already written the first three sentences of the full article: recall a polynomial @xmath0 is _ postcritically finite _ if the forward orbits of its critical points are finite . then the filled julia set of @xmath1 contains a forward invariant , finite topological tree , called the _ hubbard tree _ @xcite . the _ core entropy _ of @xmath1 is the topological entropy of the restriction of @xmath1 to its hubbard tree .. Please generate the next two sentences of the article

we shall restrict ourselves to quadratic polynomials . given @xmath2 , the external ray at angle @xmath3 determines a postcritically finite parameter @xmath4 in the mandelbrot set @xcite .

Suppose that you have an abstract for a scientific paper: we develop the canonical formalism for a system of @xmath0 bodies in lineal gravity and obtain exact solutions to the equations of motion for @xmath1 . the determining equation of the hamiltonian is derived in the form of a transcendental equation , which leads to the exact hamiltonian to infinite order of the gravitational coupling constant . in the equal mass case explicit expressions of the trajectories of the particles are given as the functions of the proper time , which show characteristic features of the motion depending on the strength of gravity ( mass ) and the magnitude and sign of the cosmological constant . as expected , we find that a positive cosmological constant has a repulsive effect on the motion , while a negative one has an attractive effect . however , some surprising features emerge that are absent for vanishing cosmological constant . for a certain range of the negative cosmological constant the motion shows a double maximum behavior as a combined result of an induced momentum - dependent cosmological potential and the gravitational attraction between the particles . for a positive cosmological constant , not only bounded motions but also unbounded ones are realized . the change of the metric along the movement of the particles is also exactly derived . * exact solutions of relativistic two - body motion in lineal gravity * + r.b . mann and d. robbins + dept . of physics , university of waterloo waterloo , ont n2l 3g1 , canada + and + t. ohta + department of physics , miyagi university of education , aoba - aramaki , sendai 980 , japan + pacs numbers : 13.15.-f , 14.60.gh , 04.80.+z + + . And you have already written the first three sentences of the full article: solving the motion of a system of @xmath0 particles interacting through their mutual gravitational forces has long been one of the important themes in physics @xcite . though an exact solution is known in the @xmath1 case in newtonian theory , in the context of the general theory of relativity the motion of the @xmath0 bodies can not be solved exactly due to dissipation of energy in the form of gravitational radiation , even when @xmath1 . hence analysis of a two body system in general relativity ( e.g. binary pulsars ) necessarily involves resorting to approximation methods such as a post - newtonian expansion @xcite .. Please generate the next two sentences of the article

however in the past decade lower dimensional versions of general relativity ( both in ( 1 + 1 ) and ( 2 + 1 ) dimensions ) have been extensively investigated from both classical and quantum perspectives . here the reduced dimensionality yields an absence of gravitational radiation .

Suppose that you have an abstract for a scientific paper: numerical simulations of the incompressible euler equations are performed using the taylor - green vortex initial conditions and resolutions up to @xmath0 . the results are analyzed in terms of the classical analyticity strip method and beale , kato and majda ( bkm ) theorem . a well - resolved acceleration of the time - decay of the width of the analyticity strip @xmath1 is observed at the highest resolution for @xmath2 while preliminary @xmath3 visualizations show the collision of vortex sheets . the bkm criterium on the power - law growth of supremum of the vorticity , applied on the same time - interval , is not inconsistent with the occurrence of a singularity around @xmath4 . these new findings lead us to investigate how fast the analyticity strip width needs to decrease to zero in order to sustain a finite - time singularity consistent with the bkm theorem . a new simple bound of the supremum norm of vorticity in terms of the energy spectrum is introduced and used to combine the bkm theorem with the analyticity - strip method . it is shown that a finite - time blowup can exist only if @xmath1 vanishes sufficiently fast at the singularity time . in particular , if a power law is assumed for @xmath1 then its exponent must be greater than some critical value , thus providing a new test that is applied to our @xmath0 taylor - green numerical simulation . our main conclusion is that the numerical results are not inconsistent with a singularity but that higher - resolution studies are needed to extend the time - interval on which a well - resolved power - law behavior of @xmath1 takes place , and check whether the new regime is genuine and not simply a crossover to a faster exponential decay . . And you have already written the first three sentences of the full article: a central open question in classical fluid dynamics is whether the incompressible three - dimensional euler equations with smooth initial conditions develop a singularity after a finite time . a key result was established in the late eighties by beale , kato and majda ( bkm ) . the bkm theorem @xcite states that blowup ( if it takes place ) requires the time - integral of the supremum of the vorticity to become infinite ( see the review by bardos and titi @xcite ) . many studies have been performed using the bkm result to monitor the growth of the vorticity supremum in numerical simulations in order to conclude yes or no regarding the question of whether a finite - time singularity might develop .. Please generate the next two sentences of the article

the answer is somewhat mixed , see _ e.g. _ references @xcite and the recent review by gibbon @xcite .

Suppose that you have an abstract for a scientific paper: the first order equation relating object and image location for a mirror of arbitrary conic - sectional shape is derived . it is also shown that the parabolic reflecting surface is the only one free of aberration and only in the limiting case of distant sources . . And you have already written the first three sentences of the full article: most elementary treatments of reflecting surfaces restrict their attention to the spherical case . in this standard case , and assuming the paraxial approximation ( all angles are small and all rays are close to the optical axis ) , the resulting equation relating the _ axial _ object and image positions and the radius of curvature of the reflecting spherical surface is @xmath0 where all parameters are one dimensional coordinates which locate the image ( @xmath1 ) , object ( @xmath2 ) , and center of curvature ( @xmath3 ) with respect to the vertex ( the intersection of the surface with the optical axis ) @xcite . a convention is typically assumed in which light rays travel from left to right in all figures . the origin of the one dimensional coordinate system employed coincides with the vertex , and locations to the right ( left ) of the vertex are positive ( negative ) . [ ptbh ] the paraxial approximation is equivalent to a first order approximation in the height ( @xmath4 ) of the incidence point ( on the surface ) of a reflecting ray . to higher order , it is found that @xmath5 consequently , spherical mirrors are aberrant at higher order since the image location is not independent of the height , @xmath4 . this paper represents a more general treatment of a mirror than is typically found in the literature .. Please generate the next two sentences of the article

the reflecting surface is assumed to be a conicoid , the surface of revolution generated by a conic . equation ( [ gauss ] ) is then derived as the special case of a spherical surface and to first order in @xmath4 .

Suppose that you have an abstract for a scientific paper: first - principles , density - functional - based electronic structure calculations are employed to study the changes in the electronic properties of @xmath0 and @xmath1 using the korringa - kohn - rostoker coherent - potential approximation method in the atomic sphere approximation ( kkr - asa cpa ) . as a function of decreasing @xmath2 @xmath3% , we find a steady decrease in the lattice constant and bulk modulus in either alloys . however , the pressure derivative of the bulk modulus displays an opposite trend . following the debye model , which relates the pressure derivative of the bulk modulus with the average phonon frequency of the crystal , it can thus be argued that @xmath4 and its disordered alloys posses a different phonon spectra in comparison to its @xmath5 counterparts . this is further justified by the marked similarity we find in the electronic structure properties such as the variation in the density of states and the hopfield parameters calculated for these alloys . the effects on the equation of state parameters and the density of states at the fermi energy , for partial replacement of @xmath6 by @xmath7 are also discussed . . And you have already written the first three sentences of the full article: in spite of being iso - structural and iso - valent to the cubic perovskite @xmath8k superconductor @xmath5 @xcite , @xmath4 remains in the normal metal state down to @xmath9k @xcite . the specific heat measurements indicate that the absence of superconductivity in @xmath4 may be due to a substantial decrease in the density of states at the fermi energy @xmath10 resulting from its relatively low unit cell volume in comparison with @xmath5 @xcite . however , electronic structure calculations show that the decrease in @xmath10 is not sizable enough to make @xmath4 non - superconducting @xcite . for both @xmath5 @xcite and @xmath4 @xcite the density of states spectra display similar characteristics , particularly in the distribution of electronic states near the fermi energy @xmath11 .. Please generate the next two sentences of the article

the electronic states at @xmath11 are dominated by @xmath12 @xmath13 states with a little admixture of @xmath2 @xmath14 states . there exists a strong van hove singularity - like feature just below @xmath11 , which is primarily derived from the @xmath12 @xmath13 bands . to account for the lack of superconductivity in @xmath4

Suppose that you have an abstract for a scientific paper: we describe a model that accounts for the complex morphology of spiral density waves raised in saturn s rings by the co - orbital satellites , janus and epimetheus . our model may be corroborated by future cassini observations of these time - variable wave patterns . . And you have already written the first three sentences of the full article: owing to typical astronomical timescales , a galaxy s spiral arms are often considered as a fixed pattern . so , too , for the numerous , tightly wound spiral waves detected in saturn s rings . in fact , both systems are dynamically active , with waves traveling away from resonant sites .. Please generate the next two sentences of the article

this is manifest only in saturn s case , where a pair of moons janus and epimetheus occupy nearly identical orbits that are interchanged every 4 years , causing the resonance locations in the rings to skip back and forth by tens of km . since spiral density waves are initiated in saturn s rings at locations where ring particle orbits are in a lindblad resonance with a perturbing moon , the starting points of waves jump as well , allowing wave trains to interfere in complex ways @xcite . high - resolution images of the rings were obtained by the cassini spacecraft s imaging science subsystem ( iss ) on 2004 july 1 and on 2005 may 20/21 .

Suppose that you have an abstract for a scientific paper: quick chemical equilibration times of hadrons ( specifically , @xmath0 , @xmath1 , @xmath2 , and @xmath3 pairs ) within a hadron gas are explained dynamically using hagedorn states , which drive particles into equilibrium close to the critical temperature . within this scheme , we use master equations and derive various analytical estimates for the chemical equilibration times . we compare our model to recent lattice results and find that for both @xmath4 mev and @xmath5 mev , the hadrons can reach chemical equilibrium almost immediately , well before the chemical freeze - out temperatures found in thermal fits for a hadron gas without hagedorn states . furthermore the ratios @xmath6 , @xmath7 , @xmath8 , and @xmath9 match experimental values well in our dynamical scenario . . And you have already written the first three sentences of the full article: ( anti-)strangeness enhancement was first observed at cern - sps energies by comparing anti - hyperons , multi - strange baryons , and kaons to @xmath10-data . it was considered a signature for quark gluon plasma ( qgp ) because , using binary strangeness production and exchange reactions , chemical equilibrium could not be reached within a standard hadron gas phase , i.e. , the chemical equilibration time was on the order of @xmath11 whereas the lifetime of a fireball in the hadronic stages is only @xmath12 @xcite . it was then proposed that there exists a strong hint for qgp at sps because strange quarks can be produced more abundantly by gluon fusion , which would account for strangeness enhancement following hadronization and rescattering of strange quarks .. Please generate the next two sentences of the article

later , however , multi - mesonic reactions were used to explain secondary production of @xmath13 and anti - hyperons @xcite . at sps they give a chemical equilibration time @xmath14 using an annihilation cross section of @xmath15 and a baryon density of @xmath16 , which is typical for evolving strongly interacting matter at sps before chemical freeze - out .

Suppose that you have an abstract for a scientific paper: a theory for the dispersion of collective magnetic excitations in superconducting cuprates is presented with the aim to cover both high and low doping regimes . besides of spin fluctuations describable in the random phase approximation ( rpa ) we allow for local spin rotations within a mode - coupling theory . at low temperatures and moderately large correlation lengths we obtain two branches of excitations which disperse up- and downwards exhibiting the hourglass behavior observed experimentally at intermediate dopings . at large and small dopings our theory essentially reduces to the rpa and spin wave theory , respectively . the low - temperature magnetic response of many high - t@xmath0 superconductors is characterized by a resonant mode inside the superconducting gap around the antiferromagnetic wave vector @xmath1 . this collective mode manifests itself as a single peak at @xmath1 which splits into two peaks dispersing up- and downwards in frequency away from @xmath1 . this unusual dispersion resembles the shape of a hourglass@xcite . theories to explain this phenomena use either a more local@xcite or an itinerant@xcite description of the magnetism . the second approach considers particle - hole excitations with spin flips which interact within the random phase approximation ( rpa ) forming a dispersing bound state in the superconducting gap . this approach yields only one branch of excitations below the stoner continuum whereas it has been established recently that the lower branch , the center of the hourglass as well as part of the upper branch lie below this continuum in the gapped region@xcite . a more theoretical argument for the incompleteness of a rpa description comes from the fact that different spin directions do not mix as a function of time in this approximation which excludes local rotations of spins known from spin wave theory . below we will present a theory which contains both spin wave theory and rpa as special cases . at intermediate dopings we will show that.... And you have already written the first three sentences of the full article: in the case of small antiferromagnetic correlation lengths @xmath48 , corresponding to the overdoped regime , the rpa should be a reasonable approximation for the spin susceptibility . the dashed line in fig . 1 shows the imaginary part of @xmath49 for @xmath50 using the parameters tb2 in table i of ref.@xcite and a chemical potential corresponding to the doping @xmath51 . the energy unit is 1 ev in the following and lengths are measured in units of the lattice constant a of the square lattice .. Please generate the next two sentences of the article

the superconducting order parameter is @xmath52 with @xmath53 , @xmath3 equal to 0.135 and @xmath54 . the dashed line in fig . 1 illustrates that most of the spectral weight resides in the bound state at the energy 0.038 and that only a small part of it has been left in the continuum at higher energies . away from @xmath55 the dashed curve in fig .

Suppose that you have an abstract for a scientific paper: we consider the simple random walk on the ( unique ) infinite cluster of super - critical bond percolation in @xmath0 with @xmath1 . we prove that , for almost every percolation configuration , the path distribution of the walk converges weakly to that of non - degenerate , isotropic brownian motion . our analysis is based on the consideration of a harmonic deformation of the infinite cluster on which the random walk becomes a square - integrable martingale . the size of the deformation , expressed by the so called corrector , is estimated by means of ergodicity arguments . = 1 . And you have already written the first three sentences of the full article: consider supercritical bond - percolation on @xmath0 , @xmath1 , and the simple random walk on the ( unique ) infinite cluster . in @xcite sidoravicius and sznitman asked the following question : is it true that for a.e . configuration in which the origin belongs to the infinite cluster , the random walk started at the origin exits the infinite symmetric slab @xmath2 through the `` top '' side with probability tending to @xmath3 as @xmath4 ?. Please generate the next two sentences of the article

sidoravicius and sznitman managed to answer their question affirmatively in dimensions @xmath5 but dimensions @xmath6 remained open . in this paper we extend the desired conclusion to all @xmath1 . as in @xcite , we will do so by proving a quenched invariance principle for the paths of the walk . random walk on percolation clusters is only one of many instances of `` statistical mechanics in random media '' that have been recently considered by physicists and mathematicians .

Suppose that you have an abstract for a scientific paper: resonance scattering has often been invoked to explain the disagreement between the observed and predicted line ratios of @xmath015.01 to @xmath015.26 ( the `` 3c/3d '' ratio ) . in this process photons of @xmath015.01 , with its much higher oscillator strength , are preferentially scattered out of the line of sight , thus reducing the observed line ratio . recent laboratory measurements , however , have found significant inner - shell lines at 15.21 and 15.26 , suggesting that the observed 3c/3d ratio results from blending . given our new understanding of the fundamental spectroscopy , we have re - examined the original solar spectra , identifying the @xmath015.21 line and measuring its flux to account for the contribution of to the @xmath015.26 flux . deblending brings the 3c/3d ratio into good agreement with the experimental ratio ; hence , we find no need to invoke resonance scattering . low opacity in @xmath015.01 also implies low opacity for fe xv @xmath0284.2 , ruling out resonance scattering as the cause of the fuzziness of and -eit 284 images . the images must , instead , be unresolved due to the large number of structures at this temperature . insignificant resonance scattering implies that future instruments with higher spatial resolution could resolve the active region plasma into its component loop structures . . And you have already written the first three sentences of the full article: the validity of the optically thin approximation for coronal plasma has been discussed in the literature since the beginnings of solar x - ray and euv spectroscopy ( pottasch 1963 , and references therein ) . resonance scattering of @xmath015.01 ( @xmath1 , known as `` 3c '' ) , in particular , has been the subject of a long - standing controversy . observations of the ratio of the 3c flux to that of @xmath015.26 ( @xmath2 , known as `` 3d '' ) gave ratios in the range 1.6 to 2.3 ( rugge & mckenzie 1985 ; schmelz 1997 ; saba 1999 ) , whereas collisional radiative models predicted a ratio of about four ( smith 1985 ; loulergue & nussbaumer 1973 ; bhatia & doschek 1992 ; cornille 1994 ) .. Please generate the next two sentences of the article

schmelz and saba also found , using the flat crystal spectrometer ( fcs ) on the _ solar maximum mission _ , that the lowest values were preferentially at the solar limb . this center - to - limb effect bolstered the argument for resonance scattering of @xmath015.01 , given that the limb photons traverse a longer path ( _ cf , _ phillips 1996 ) .

Suppose that you have an abstract for a scientific paper: within the framework of the operator product expansion ( ope ) and the renormalization group equation ( rge ) , we show that the temperature and chemical potential dependence of the zeroth moment of a spectral function ( sf ) is completely determined by the one - loop structure in an asymptotically free theory , and in particular in qcd . logarithmic corrections are found to play an essential role in the derivation . this exact result constrains the shape of sf s , and implies striking effects near phase transitions . phenomenological parameterizations of the sf , often used in applications such as the analysis of lattice qcd data or qcd sum rule calculations at finite temperature and baryon density must satisfy these constraints . we also explicitly illustrate in detail the exact sum rule in the gross - neveu model . . And you have already written the first three sentences of the full article: hadronic properties at finite temperature and baryon density are of great importance in the phenomenology of heavy ions collisions , star interior and the early universe . moreover , the theoretical expectation of transitions to a chirally symmetric phase and , perhaps , to a quark - gluon plasma phase contributes to the interest in studying the effect of matter and temperature on the quantum chromodynamics ( qcd ) vacuum . our present understanding of qcd at finite temperature ( @xmath0 ) and baryon density ( or chemical potential @xmath1 ) is mainly limited in the euclidean realm , due to the lack of non - perturbative and systematic calculating tools directly in the minkowski space .. Please generate the next two sentences of the article

typical methods , with qcd lagrangian as the starting point , are the ope and lattice simulations . because these two formulations are intrinsically euclidean , only static quantities are conveniently studied . in order to gain dynamical informations , which are more accessible experimentally , the analytic structure implemented through dispersion relations often have to be invoked within the theory of linear response . in principle

Suppose that you have an abstract for a scientific paper: obtaining a thermodynamically accurate phase diagram through numerical calculations is a computationally expensive problem that is crucially important to understanding the complex phenomena of solid state physics , such as superconductivity . in this work we show how this type of analysis can be significantly accelerated through the use of modern gpus . we illustrate this with a concrete example of free energy calculation in multi - band iron - based superconductors , known to exhibit a superconducting state with oscillating order parameter ( op ) . our approach can also be used for classical bcs - type superconductors . with a customized algorithm and compiler tuning we are able to achieve a 19x speedup compared to the cpu ( 119x compared to a single cpu core ) , reducing calculation time from minutes to mere seconds , enabling the analysis of larger systems and the elimination of finite size effects . fflo , pnictides , nvidia cuda , pgi cuda fortran , superconductivity * program summary * _ manuscript title : _ gpu - based acceleration of free energy calculations in solid state physics + _ authors : _ micha januszewski , andrzej ptok , dawid crivelli , bartomiej gardas + _ journal reference : _ + _ catalogue identifier : _ + _ licensing provisions : lgplv3 _ + _ programming language : _ fortran , cuda c + _ computer : _ any with a cuda - compliant gpu + _ operating system : _ no limits ( tested on linux ) + _ ram : _ typically tens of megabytes . + _ keywords : _ superconductivity , fflo , cuda , openmp , openacc , free energy + _ classification : _ 7 , 6.5 + _ nature of problem : _ gpu - accelerated free energy calculations in multi - band iron - based superconductor models . + _ solution method : _ parallel parameter space search for a global minimum of free energy . + _ unusual features : _ + the same core algorithm is implemented in fortran with openmp and openacc compiler annotations , as well as in cuda c. the original fortran implementation targets the cpu.... And you have already written the first three sentences of the full article: the last decade brought a dynamic evolution of the computing capabilities of graphics processing units ( gpus ) . in that time , the performance of a single card increased from tens of gflops in nvxx to tflops in the newest kepler / maxwell nvidia chips @xcite . this raw processing power did not go unnoticed by the engineering and science communities , which started applying gpus to accelerate a wide array of calculations in what became known as gpgpu general - purpose computing on gpus . this led to the development of special gpu variants optimized for high performance computing ( e.g. the nvidia tesla line ) , but it should be noted that even commodity graphics cards , such as those from the nvidia geforce series , still provide enormous computational power and can be a very economical ( both from the monetary and energy consumption point of view ) alternative to large cpu clusters .. Please generate the next two sentences of the article

the spread of gpgpu techniques was further facilitated by the development of cuda and opencl parallel programming paradigms allowing efficient exploitation of the available gpu compute power without exposing the programmer to too many low - level details of the underlying hardware .

Suppose that you have an abstract for a scientific paper: we present results from high - resolution hydrodynamic simulations of isolated smc- and milky way - sized galaxies that include a model for feedback from galactic cosmic rays ( crs ) . we find that crs are naturally able to drive winds with mass loading factors of up to @xmath0 in dwarf systems . the scaling of the mass loading factor with circular velocity between the two simulated systems is consistent with @xmath1 required to reproduce the faint end of the galaxy luminosity function . in addition , simulations with cr feedback reproduce both the normalization and the slope of the observed trend of wind velocity with galaxy circular velocity . we find that winds in simulations with cr feedback exhibit qualitatively different properties compared to sn driven winds , where most of acceleration happens violently in situ near star forming sites . the cr - driven winds are accelerated gently by the large - scale pressure gradient established by crs diffusing from the star - forming galaxy disk out into the halo . the cr - driven winds also exhibit much cooler temperatures and , in the smc - sized system , warm ( @xmath2 k ) gas dominates the outflow . the prevalence of warm gas in such outflows may provide a clue as to the origin of ubiquitous warm gas in the gaseous halos of galaxies detected via absorption lines in quasar spectra . . And you have already written the first three sentences of the full article: galactic winds are observed to be ubiquitous in galaxies that have recently experienced significant amounts star formation ( see e.g. , * ? ? ? * for a review ) . these outflows represent a fundamental part of galaxy formation models , because the absence of outflows galaxy star formation rates ( sfrs ) are much higher than those observed ( e.g. , * ? ? ? * ) and baryon fractions in the disk are close to the universal value ( e.g. , * ? ? ?. Please generate the next two sentences of the article

* ) , much higher than inferred from observations . in contrast , models that include a variety of feedback effects predict much lower sfrs and baryon fractions . additionally , outflows are required to drive metal - enriched gas out of galaxies , as suggested by both observational ( e.g. * ? ? ? * ) and theoretical ( e.g. * ? ? ? * ) work .

Suppose that you have an abstract for a scientific paper: we discuss several physical constraints on the nature of the active regions ( ar ) in seyfert 1 galaxies , and show that a plausible model consistent with these constraints is one in which the ars are magnetically confined and `` fed '' . the unique x - ray index of these sources points to a large compactness parameter ( @xmath0 ) . this , together with the conditions required to account for the observed optical depth being close to unity , suggests that the magnetic energy density in the ar should be comparable to the equipartition value in the accretion disk , and that it should be released in a flare - like event above the surface of the cold accretion disk . we consider the various issues pertaining to magnetic flares and attempt to construct a coherent picture , including a reason for the optical depth in the ar being @xmath1 , and an understanding of the characteristics of the x - ray reflection component and the power density spectra associated with this high - energy emission . #1#2#3#1 , a&a , # 2 , # 3 # 1#2#3#1 , a&as , # 2 , # 3 # 1#2#3#1 , aj , # 2 , # 3 # 1#2#3#1 , _ apj _ , * # 2 * , # 3 . # 1#2#3#1 , _ apj ( letters ) _ , * # 2 * , # 3 . # 1#2#3#1 , apjs , # 2 , # 3 # 1#2#3#1 , ara&a , # 2 , # 3 # 1#2#3#1 , baas , # 2 , # 3 # 1#2#3#1 , icarus , # 2 , # 3 # 1#2#3#1 , _ mnras _ , * # 2 * , # 3 . # 1#2#3#1 , _ nature _ , * # 2 * , # 3 . # 1#2#3#1 , pasj , # 2 , # 3 # 1#2#3#1 , pasp , # 2 , # 3 # 1#2#3#1 , qjras , # 2 , # 3 # 1#2#3#1 , science , # 2 , # 3 # 1#2#3#1 , soviet astr . , # 2 , # 3 # 1#2#3#1 , soviet astr . lett . , # 2 , # 3 # 1#2#3#4#1 , # 2 , # 3 , # 4 # 1#1 submitted to the astrophysical journal . And you have already written the first three sentences of the full article: x - ray emission is a major contributor to the observed spectrum of seyfert galaxies , and yet the physics of the emitting region is still not well understood . the most common and ( thus far ) successful approach to this problem , to which we shall refer as the ` spectral approach ' ( sa ) , makes very simple assumptions about the geometry and/or the particle heating mechanisms , but uses a detailed microphysical approach to account for the particle - photon interactions and to derive the spectrum . this spectrum is then compared with the observations in order to place constraints on the parameters of the emitting regions .. Please generate the next two sentences of the article

the early models assumed a non - thermal pair dominated plasma . ( for a comprehensive review of non - thermal models see svensson 1994 . )

Suppose that you have an abstract for a scientific paper: we introduce a novel class of interaction - enabled topological crystalline insulators in two- and three - dimensional electronic systems , which we call `` topological crystalline magnet . '' it is protected by the product of the time - reversal symmetry @xmath0 and a mirror symmetry or a rotation symmetry @xmath1 . a topological crystalline magnet exhibits two intriguing features : ( i ) it can not be adiabatically connected to any slater insulator and ( ii ) the edge state is robust against coupling electrons to the edge . these features are protected by the anomalous symmetry transformation property @xmath2 of the edge state . an anisotropic response to the external magnetic field can be an experimental signature . . And you have already written the first three sentences of the full article: recent years have seen a great expansion of topological quantum materials beyond time - reversal - invariant topological insulators @xcite , driven by the search for symmetry - protected topological ( spt ) states of matter that are distinct from trivial states only in the presence of certain symmetry . this underlying symmetry can be associated with conservation of internal quantum numbers such as charge and spin @xcite , or with spatial operations such as rotation and reflection @xcite . since spatial symmetry is a common property of all crystals , a wide array of topological band insulators protected by various crystal symmetries , commonly referred to as topological crystalline insulators ( tcis ) @xcite , has been theorized . the hallmark of a tci is the existence of topologically protected gapless excitations on surfaces that preserve the relevant crystal symmetry .. Please generate the next two sentences of the article

a notable class of tcis protected by reflection symmetry was predicted and observed in the iv - vi semiconductors sn@xmath3pb@xmath4(te , se ) @xcite , and the symmetry protection of the topological surface states has been demonstrated @xcite . more recently , tcis have been generalized to band insulators with magnetic point group symmetries @xcite , nonsymmorphic symmetries @xcite , and with both glide reflection and time - reversal symmetry @xcite .

Suppose that you have an abstract for a scientific paper: so far analysis of the quasinormal spectrum of a massive charged scalar field in the black hole background has been limited by the regime of small @xmath0 and @xmath1 , where @xmath2 , @xmath3 ( @xmath4 , @xmath5 ) are mass and charge of the field ( black hole ) . here we shall present a comprehensive picture of quasinormal modes , late - time tails and stability of a massive charged scalar field around kerr - newman black holes for any physically meaningful values of the parameters . we shall show that despite presence of the two mechanisms of superradiance ( owing to black hole s rotation and charge ) and the massive term creating growing bound states , there is no indication of instability under quasinormal modes boundary conditions . we have shown that for some moderate values of @xmath1 dominant quasinormal modes may have _ arbitrarily small real oscillation frequencies _ @xmath6 . an analytic formula for the quasinormal modes has been derived in the regime of large @xmath1 . the larger the field s charge , the sooner asymptotic tails dominate in a signal , making it difficult to extract quasinormal frequencies from a time - domain profile . analytic expressions for intermediate and asymptotically late - time tails have been found for the reissner - nordstrm black hole . for the near extremal kerr - newman black holes we have obtained a more general picture of the _ mode branching _ found recently for massless fields ( arxiv:1212.3271 ) in the kerr background . . And you have already written the first three sentences of the full article: the general solution for an asymptotically flat black hole in the einstein - maxwell theory is given by the kerr - newman solution . it describes an electrically charged rotating black hole with its three parameters : mass , charge and angular momentum . a systematic study of the fields dynamic in the vicinity of a black hole is essential for understanding black - hole evaporation , quasinormal modes and stability .. Please generate the next two sentences of the article

the linear dynamics of a charged massive scalar field in the background of a charged black hole is characterized by the two dimensionless parameters @xmath0 and @xmath1 . a black hole is not believed to be formed possessing considerable electric charge , and , once it is formed , it undergoes a rather quick discharging @xcite . yet , even if a black hole has a very small charge of order @xmath7 , the parameter @xmath1 need not be small .

Suppose that you have an abstract for a scientific paper: we present a deep image of the radio galaxy mrc 1138262 taken with the _ hubble space telescope ( hst ) _ at a redshift of @xmath0 . the galaxy is known to have properties of a cd galaxy progenitor and be surrounded by a 3 mpc - sized structure , identified with a protocluster . the morphology shown on the new deep _ hst _ acs image is reminiscent of a spider s web . more than 10 individual clumpy features are observed , apparently star - forming satellite galaxies in the process of merging with the progenitor of a dominant cluster galaxy 11 gyr ago . there is an extended emission component , implying that star formation was occurring over a 50@xmath140 kpc region at a rate of more than 100 @xmath2 yr@xmath3 . a striking feature of the newly named `` spiderweb galaxy '' is the presence of several faint linear galaxies within the merging structure . the dense environments and fast galaxy motions at the centres of protoclusters may stimulate the formation of these structures , which dominate the faint resolved galaxy populations in the hubble ultra deep field . the new image provides a unique testbed for simulations of forming dominant cluster galaxies . . And you have already written the first three sentences of the full article: distant powerful radio galaxies are important laboratories for studying the formation and evolution of massive galaxies , because they are among the most luminous and largest known galaxies in the early universe and likely progenitors of dominant cluster galaxies ( e.g. * ? ? ? they are generally embedded in giant ( cd - sized ) ionized gas halos ( e.g. * ? ? ? * ) surrounded by galaxy overdensities , whose structures have sizes of a few mpc @xcite .. Please generate the next two sentences of the article

the radio galaxy hosts have clumpy optical morphologies @xcite , spectra indicative of extreme star formation ( e.g. * ? ? ? * ) , and large stellar masses @xcite . because the radio lifetimes ( few times 10@xmath4 yr ) are much smaller than cosmological timescales , the statistics are consistent with every dominant cluster galaxy having gone through a luminous radio phase during its evolution @xcite

Suppose that you have an abstract for a scientific paper: flapan , _ et al _ @xcite showed that every spatial embedding of @xmath0 , the complete graph on ten vertices , contains a non - split three - component link ( @xmath0 is _ intrinsically triple - linked _ ) . the papers @xcite and @xcite extended the list of known intrinsically triple - linked graphs in @xmath1 to include several other families of graphs . in this paper , we will show that while some of these graphs can be embedded 3-linklessly in @xmath2 , @xmath0 is intrinsically triple - linked in @xmath2 . . And you have already written the first three sentences of the full article: _ real projective 3-space _ , @xmath2 , is defined to be the quotient @xmath3 , where @xmath4 is the antipodal relation @xmath5 and can be thought of as the disk , @xmath6 , with antipodal boundary points identified . projective space has a non - trivial first homology group , @xmath7 .. Please generate the next two sentences of the article

the generator for the group , @xmath8 , is the cycle originating from the line in @xmath6 that runs between the north and south poles . mroczkowski @xcite has shown that every knot in @xmath2 can be transformed into either the trivial cycle or @xmath8 by crossing changes and generalized reidemeister moves on an @xmath9 projection of the knot .

Suppose that you have an abstract for a scientific paper: the ground states of bose - einstein condensates of spin-2 bosons are classified into three distinct ( ferromagnetic , `` antiferromagnetic `` , and cyclic ) phases depending on the s - wave scattering lengths of binary collisions for total - spin 0 , 2 , and 4 channels . many - body spin correlations and magnetic response of the condensate in each of these phases are studied in a mesoscopic regime , while low - lying excitation spectra are investigated in the thermodynamic regime . in the mesoscopic regime , where the system is so tightly confined that the spatial degrees of freedom are frozen , the exact , many - body ground state for each phase is found to be expressed in terms of the creation operators of pair or trio bosons having spin correlations . these pairwise and trio - wise units are shown to bring about some unique features of spin-2 becs such as a huge jump in magnetization from minimum to maximum possible values and the robustness of the minimum - magnetization state against an applied magnetic field . in the thermodynamic regime , where the system is spatially uniform , low - lying excitation spectra in the presence of magnetic field are obtained analytically using the bogoliubov approximation . in the ferromagnetic phase , the excitation spectrum consists of one goldstone mode and four single - particle modes . in the antiferromagnetic phase , where spin - singlet `` pairs '' undergo bose - einstein condensation , the spectrum consists of two goldstone modes and three massive ones , all of which become massless when magnetic field vanishes . in the cyclic phase , where boson `` trios " condense into a spin - singlet state , the spectrum is characterized by two goldstone modes , one single - particle mode having a magnetic - field - independent energy gap , and a gapless single - particle mode that becomes massless in the absence of magnetic field . = -0.8truecm . And you have already written the first three sentences of the full article: bose - einstein condensates ( becs ) of trapped alkali atoms have internal degrees of freedom due to the hyperfine spin of the atoms . when a bec is trapped in a magnetic potential , these degrees of freedom are frozen and the state of the bec is described at a mean - field level by a scalar order parameter . when a bec is trapped in an optical potential , however , the spin degrees of freedom are liberated , giving rise to a rich variety of phenomena such as spin domains @xcite and textures @xcite . here the order parameter has @xmath0 components that transform under spatial rotation as the spherical tensor of rank @xmath1 , where @xmath2 is the hyperfine spin of bosons .. Please generate the next two sentences of the article

mean field theories ( mfts ) of spinor becs were put forth for both spin-1 @xcite and spin-2 @xcite cases . according to them

Suppose that you have an abstract for a scientific paper: helicity and @xmath0 effect driven by the nonaxisymmetric tayler instability of toroidal magnetic fields in stellar radiation zones are computed . in the linear approximation a purely toroidal field always excites pairs of modes with identical growth rates but with opposite helicity so that the net helicity vanishes . if the magnetic background field has a helical structure by an extra ( weak ) poloidal component then one of the modes dominates producing a net kinetic helicity anticorrelated to the current helicity of the background field . + the mean electromotive force is computed with the result that the @xmath0 effect by the most rapidly growing mode has the same sign as the current helicity of the background field . the @xmath0 effect is found as too small to drive an @xmath1 dynamo but the excitation conditions for an @xmath2 dynamo can be fulfilled for weak poloidal fields . moreover , if the dynamo produces its own @xmath0 effect by the magnetic instability then problems with its sign do not arise . for all cases , however , the @xmath0 effect shows an extremely strong concentration to the poles so that a possible @xmath2 dynamo might only work at the polar regions . hence , the results of our linear theory lead to a new topological problem for the existence of large - scale dynamos in stellar radiation zones on the basis of the current - driven instability of toroidal fields . [ firstpage ] magnetohydrodynamics ( mhd ) instabilities stars : magnetic fields stars : interiors . . And you have already written the first three sentences of the full article: hydromagnetic dynamos can be understood as magnetic instabilities driven by a special flow pattern in fluid conductors . there are , however , strong restrictions on the characteristics of such flows ( see dudley & james 1989 ) as well as on the geometry of the resulting magnetic fields @xcite . the restrictions even exclude any dynamo activity for a number of flows . we mention as an example that differential rotation alone can never maintain a dynamo ( elsasser 1946 ) .. Please generate the next two sentences of the article

an open question is whether magnetic instabilities are able to excite a sufficiently complicated motion that together with a ( given ) background flow can generate magnetic fields . @xcite suggested that nonuniformly rotating disks can produce a dynamo when magnetorotational ( mri ) and magnetic buoyancy instabilities are active .

Suppose that you have an abstract for a scientific paper: we describe the first results of a programme to obtain rotation curves of @xmath0 disc galaxies in the near - infrared using the h@xmath1 emission line in order to study the tully - fisher relationship . to put any observed evolution into perspective and to investigate any possible selection biases , we constructed a control sample of low redshift galaxies that had rotation velocities and images available for measuring their dynamical , photometric , and morphological properties . compared to local objects with isophotal sizes similar to the high redshift targets , we find that our sample of galaxies with spatially resolved rotation curves , the most distant sample so far ( @xmath2 ) , clearly reveals a brightening of @xmath3 mag in the rest - frame b - band . the observed offset can be explained by a combination of increasing surface brightness , decreasing rotation speeds , and slightly smaller disc scale lengths of the high redshift galaxies . . And you have already written the first three sentences of the full article: like the fundamental plane for early type galaxies @xcite the tully - fisher relation for disc galaxies embodies fundamental implications for the relationship between the mass of the galaxy , its star - formation history , specific angular momentum and dark matter content and distribution . broadly speaking , there are two competing models to explain the tully - fisher relation . the first of these is that it is a consequence of self - regulated star formation in discs with different masses ( e.g. , * ? ? ?. Please generate the next two sentences of the article

* ) , i.e. , the competition of disc instability ( which promotes star formation ) with supernovae induced porosity ( which inhibits star - formation ) . the model is not the complete answer , however , since it does not explain the mass - to - light ratios or the scale - lengths of the discs . in the second model

Suppose that you have an abstract for a scientific paper: we prove that the differential equation @xmath0 has continuous weak periodic solutions and compute their periods . then , we use the harmonic balance method until order six to approach these periods and to illustrate how the sharpness of the method increases with the order . our computations rely on the grbner basis method . . And you have already written the first three sentences of the full article: the nonlinear differential equation @xmath1 appears in the modeling of certain phenomena in plasma physics @xcite . in @xcite , mickens calculates the period of its periodic orbits and also uses the @xmath2-th order harmonic balance method ( hbm ) , for @xmath3 , to obtain approximations of these periodic solutions and of their corresponding periods . strictly speaking , it can be easily seen that neither equation , nor its associated system @xmath4 which is singular at @xmath5 , have periodic solutions . our first result gives two different interpretations of mickens computation of the period .. Please generate the next two sentences of the article

the first one in terms of weak ( or generalized ) solutions . in this work a weak solution will be a function satisfying the differential equation on an open and dense set , but being of class @xmath6 at some isolated points .

Suppose that you have an abstract for a scientific paper: we report on the properties of nuclear regions in the toomre sequence of merging galaxies , based on imaging data gathered with the _ hubble space telescope _ wfpc2 camera . we have imaged the 11 systems in the proposed evolutionary merger sequence in the f555w and f814w broad - band filters , and in h@xmath0 + [ ] narrow - band filters . the broad - band morphology of the nuclear regions varies from non - nucleated starburst clumps through dust - covered nuclei to a nucleated morphology . there is no unambiguous trend in the morphology with merger stage . the emission - line morphology is extended beyond the nucleus in most cases , but centrally concentrated ( within 1 kpc ) emission - line gas can be seen in the four latest - stage merger systems . we have quantified the intrinsic luminosity densities and colors within the inner 100 pc and 1 kpc of each identified nucleus . we find little evidence for a clear trend in nuclear properties along the merger sequence , other than a suggestive rise in the nuclear luminosity density in the most evolved members of the sequence . the lack of clear trends in nuclear properties is likely due both to the effects of obscuration and geometry , as well as the physical variety of galaxies included in the toomre sequence . . And you have already written the first three sentences of the full article: disk galaxy mergers are believed to be responsible for triggering a variety of global _ and _ nuclear responses in galaxies . the global effects have been well documented , both with observations , starting with zwicky s extensive work ( 1950 , 1956 , 1964 ) , and with numerical simulations , first convincingly demonstrated by @xcite . work during the last decades strongly suggests that a fraction of elliptical galaxies has formed as a result of disk galaxy merging ( see * ? ? ?. Please generate the next two sentences of the article

* and references therein ) . the morphology of tidal tails has been used to trace the mass distribution in galactic halos @xcite , and the tails themselves are possible birthplaces of some dwarf galaxies @xcite .

Suppose that you have an abstract for a scientific paper: let @xmath0 be a connected , semisimple lie group with finite center and let @xmath1 be a maximal compact subgroup . we investigate a method to compute multiplicities of @xmath1-types in the discrete series using a rational expression for a generating function obtained from blattner s formula . this expression involves a product with a character of an irreducible finite dimensional representation of @xmath1 and is valid for any discrete series system . other results include a new proof of a symmetry of blattner s formula , and a positivity result for certain low rank examples . we consider in detail the situation for @xmath0 of type split @xmath2 . the motivation for this work came from an attempt to understand pictures coming from blattner s formula , some of which we include in the paper . . And you have already written the first three sentences of the full article: in @xcite , a proof of a formula for the restriction of a discrete series representation ( see @xcite ) of a connected , linear , semisimple lie group to a maximal compact subgroup is given . this formula was first conjectured by blattner . we recall the formula and its context briefly , from the point of view of root system combinatorics . throughout the paper. Please generate the next two sentences of the article

, @xmath3 denotes a semisimple lie algebra over @xmath4 with a fixed cartan subalgebra @xmath5 . let @xmath6 denote the corresponding root system with weyl group @xmath7 .

Suppose that you have an abstract for a scientific paper: the experimental demonstration of the modification of the casimir force between a gold coated sphere and a single - crystal si membrane by light pulses is performed . the specially designed and fabricated si membrane was irradiated with 514 nm laser pulses of 5ms width in high vacuum leading to a change of the charge - carrier density . the difference in the casimir force in the presence and in the absence of laser radiation was measured by means of an atomic force microscope as a function of separation at different powers of the absorbed light . the total experimental error of the measured force differences at a separation of 100 nm varies from 10 to 20% in different measurements . the experimental results are compared with theoretical computations using the lifshitz theory at both zero and laboratory temperatures . the total theoretical error determined mostly by the uncertainty in the concentration of charge carriers when the light is incident is found to be about 14% at separations less than 140 nm . the experimental data are consistent with the lifshitz theory at laboratory temperature , if the static dielectric permittivity of high - resistivity si in the absence of light is assumed to be finite . if the dc conductivity of high - resistivity si in the absence of light is included into the model of dielectric response , the lifshitz theory at nonzero temperature is shown to be experimentally inconsistent at 95% confidence . the demonstrated phenomenon of the modification of the casimir force through a change of the charge - carrier density is topical for applications of the lifshitz theory to real materials in fields ranging from nanotechnology and condensed matter physics to the theory of fundamental interactions . . And you have already written the first three sentences of the full article: after many years of pure academic research , the casimir effect @xcite is presently of much interest in connection with applications in nanomechanical devices @xcite , noncontact friction @xcite , carbon nanotubes @xcite , bose - einstein condensation @xcite and for constraining predictions of modern unification theories of fundamental interactions @xcite . these areas of application were made possible by extensive experimental investigation of the casimir force @xcite and the generalization to real materials of field - theoretical methods which were applicable to only idealized boundaries ( see reviews @xcite ) . the basic theory of the casimir and van der waals forces at nonzero temperature proposed by lifshitz @xcite allows one to calculate all quantities of physical interest using the dielectric permittivity of boundary materials along the imaginary frequency axis .. Please generate the next two sentences of the article

this theory was originally developed for the configuration of two semispaces and was later extended for any layer structure @xcite . using the proximity force theorem @xcite , lifshitz - type formulas for the configuration of a sphere or a cylinder above a plate were obtained and successfully used for the interpretation of experimental data @xcite . for a long time , the lack of exact results for these configurations made it possible to question the validity of the comparison of experiment and theory based on the proximity force theorem . recently , however , both the exact analytical @xcite and numerical @xcite results for the casimir force between a sphere ( cylinder ) and a plate were obtained demonstrating that at small @xmath0 the corrections to the proximity force theorem for both configurations are in fact less than @xmath1 ( @xmath0 is the separation between a cylinder or a sphere of radius @xmath2 and a plate ) , i.e. , less than it was supposed in the comparison of experiment with theory .

Suppose that you have an abstract for a scientific paper: in this paper we study necessary conditions of flexibility for semidiscrete surfaces . for 2-ribbon semidiscrete surfaces we prove their one - parametric finite flexibility . in particular we write down a system of differential equations describing flexions in the case of existence . further we find infinitesimal criterions of @xmath0-ribbon flexibility . finally , we discuss the relation between general semidiscrete surface flexibility and @xmath0-ribbon flexibility . . And you have already written the first three sentences of the full article: a mapping @xmath1 , where the dependence on the continuous parameter is smooth , is called a _ semidiscrete surface_. let us connect @xmath2 with @xmath3 by segments for all possible pares @xmath4 . the resulting piecewise smooth surface is a _ piecewise ruled surface_. in this paper we study infinitesimal and higher order flexibility conditions for such semidiscrete surfaces . by _ flexions _ of a semidiscrete surface @xmath5 we understand deformations that isometrically deform corresponding ruled surfaces and in addition that preserve all line segments connecting @xmath2 with @xmath3 .. Please generate the next two sentences of the article

many questions on discrete polyhedral surfaces have their origins in classical theory of smooth surfaces . flexibility is not an exception from this rule .

Suppose that you have an abstract for a scientific paper: we present an updated version of skirt , a 3d monte carlo radiative transfer code developed to simulate dusty galaxies . the main novel characteristics of the skirt code are the use of a stellar foam to generate random positions , an efficient combination of eternal forced scattering and continuous absorption , and a new library approach that links the radiative transfer code to the dustem dust emission library . this approach enables a fast , accurate and self - consistent calculation of the dust emission of arbitrary mixtures of transiently heated dust grains and polycyclic aromatic hydrocarbons , even for full 3d models containing millions of dust cells . we have demonstrated the accuracy of the skirt code through a set of simulations based on the edge - on spiral galaxy ugc4754 . the models we ran were gradually refined from a smooth , 2d , lte model to a fully 3d model that includes nlte dust emission and a clumpy structure of the dusty ism . we find that clumpy models absorb uv and optical radiation less efficiently than smooth models with the same amount of dust , and that the dust in clumpy models is on average both cooler and less luminous . our simulations demonstrate that , given the appropriate use of optimization techniques , it is possible to efficiently and accurately run monte carlo radiative transfer simulations of arbitrary 3d structures of several million dust cells , including a full calculation of the nlte emission by arbitrary dust mixtures . . And you have already written the first three sentences of the full article: the effects of absorption and scattering by interstellar dust grains on the structural parameters of galaxies has been a long - standing and controversial issue . the only way to tackle this problem is to properly solve the continuum radiative transfer equation , taking into account realistic geometries and the physical processes of absorption and multiple anisotropic scattering . over the years , many different and complementary approaches have been developed to tackle the continuum radiative transfer problem in simple geometries such as spherical or plane - parallel symmetry .. Please generate the next two sentences of the article

while one - dimensional radiative transfer calculations have been crucial to isolate and demonstrate the often counter - intuitive aspects of important parameters such as star - dust geometry , dust scattering properties and clumping @xcite , we need more sophisticated radiative transfer models to model complicated systems such as disc galaxies in detail . thanks to new techniques and ever increasing computing power , the construction of 2d and 3d realistic radiative transfer models is now possible . a complementary and powerful way to study

Suppose that you have an abstract for a scientific paper: discovery voyage into the age of : . And you have already written the first three sentences of the full article: our title clearly alludes to the story of columbus landing in what he called the west indies " , which later on turned out to be part of the new world " . i have substituted antarctica in place of the new world " , following a quip from frank paige after he realized that i was talking all the time about _ penguins_. at the end of the millennium , we are indeed on another discovery voyage . we are at the dawn of observing cp violation in the b system .. Please generate the next two sentences of the article

the stage is the emerging penguins . well , had columbus seen penguins in _ his _ west indies " , he probably would have known he was onto something really new .

Suppose that you have an abstract for a scientific paper: can boutet de monvel s algebra on a compact manifold with boundary be obtained as the algebra @xmath0 of pseudodifferential operators on some lie groupoid @xmath1 ? if it could , the kernel @xmath2 of the principal symbol homomorphism would be isomorphic to the groupoid @xmath3 . while the answer to the above question remains open , we exhibit in this paper a groupoid @xmath1 such that @xmath3 possesses an ideal @xmath4 isomorphic to @xmath2 . in fact , we prove first that @xmath5 with the @xmath6-algebra @xmath7 generated by the zero order pseudodifferential operators on the boundary and the algebra @xmath8 of compact operators . as both @xmath9 and @xmath10 are extensions of @xmath11 by @xmath12 ( @xmath13 is the co - sphere bundle over the boundary ) we infer from a theorem by voiculescu that both are isomorphic . . And you have already written the first three sentences of the full article: boutet de monvel s calculus @xcite is a pseudodifferential calculus on manifolds with boundary . it includes the classical differential boundary value problems as well as the parametrices to elliptic elements . many operator - algebraic aspects of this algebra ( spectral invariance , noncommutative residues and traces , composition sequence , @xmath14-theory ) have been studied recently @xcite .. Please generate the next two sentences of the article

the problem of identifying this algebra as the pseudodifferential algebra ( or as an ideal of one ) of a lie groupoid may be the key to an effective application of the methods of noncommutative geometry . if that is acomplished , one could then seek for extensions of the calculus , and for a better understanding of its index theory @xcite .

Suppose that you have an abstract for a scientific paper: let @xmath0 and @xmath1 be convex polytopes in @xmath2 such that @xmath3 . we give criteria describing when the mixed volume is strictly increasing @xmath4 this geometric result allows us to characterize sparse polynomial systems with newton polytopes @xmath5 whose number of isolated solutions equals the normalized volume of the convex hull of @xmath6 . in addition , we obtain an analog of cramer s rule for sparse polynomial systems . . And you have already written the first three sentences of the full article: the mixed volume is one of the fundamental notions in the theory of convex bodies . it plays a central role in the brunn minkowski theory and in the theory of sparse polynomial systems .. Please generate the next two sentences of the article

the mixed volume is the polarization of the volume form on the space of convex bodies in @xmath2 . more precisely , let @xmath7 be @xmath8 convex bodies in @xmath2 and @xmath9 the euclidean volume of a body @xmath10 .

Suppose that you have an abstract for a scientific paper: we present the first results from 60ks of observations of arp 220 using the acis - s instrument on chandra . we report the detection of several sources near the galaxy s nucleus , including a point source with a hard spectrum that is coincident with the western radio nucleus b. this point source is mildly absorbed ( @xmath0 ) and has an estimated luminosity of @xmath1 erg / s . in addition , a fainter source may coincide with the eastern nucleus a. extended hard x - ray emission in the vicinity raises the total estimated nuclear 2 - 10 kev x - ray luminosity to @xmath2 erg / s , but we can not rule out a hidden agn behind columns exceeding @xmath3 we also detect a peak of soft x - ray emission to the west of the nucleus , and a hard point source 2.5 kpc from the nucleus with a luminosity of @xmath4 erg / s . . And you have already written the first three sentences of the full article: ultraluminous infrared galaxies ( ulirgs ) have quasar - like bolometric luminosities ( @xmath5 ) dominated by the far - infrared ( 81000@xmath6 m ) part of the spectrum ( sanders & mirabel , 1996 ) . almost all ulirgs are interacting or merging galaxies ( clements et al . 1996 ) , possibly linking them to the transformation of disk galaxies into ellipticals ( eg . wright et al , 1990 ; baker & clements , 1997 ) .. Please generate the next two sentences of the article

the prodigious luminosity of ulirgs is thought to be powered by a massive starburst , a dust buried agn or some combination of the two . despite a decade of work we still have not been able to decide between these paradigms .

Suppose that you have an abstract for a scientific paper: we introduce a novel multiobjective optimization algorithm based on the conformational space annealing ( csa ) algorithm , mocsa . it has three characteristic features : ( a ) dominance relationship and distance between solutions in the objective space are used as the fitness measure , ( b ) update rules are based on the fitness as well as the distance between solutions in the decision space and ( c ) it uses a constrained local minimizer . we have tested mocsa on 12 test problems , consisting of zdt and dtlz test suites . benchmark results show that solutions obtained by mocsa are closer to the pareto front and covers a wider range of the objective space than those by the elitist non - dominated sorting genetic system ( nsga2 ) . conformational space annealing , multiobjective optimization , genetic algorithm , evolutionary algorithm , pareto front . And you have already written the first three sentences of the full article: the multiobjective optimization problem ( moop ) is to optimize two or more objective functions simultaneously , subject to given constraints . the multiobjective optimization can be applied to problems where the final decision should be made considering two or more conflicting objectives . moop occurs in various fields such as industrial design , finance , management and many engineering areas .. Please generate the next two sentences of the article

practical goals in these fields can be generalized in such a way that the cost of a process is minimized while the quality of its product is maximized . the primary goal is to find a set of solutions that any individual objective function can not be improved without deteriorating the other objective functions , and such a set is called a pareto set . for efficient decision making ,

Suppose that you have an abstract for a scientific paper: the column density distribution of trapped oh@xmath0 ions in a 22-pole ion trap is measured for different trap parameters . the density is obtained from position - dependent photodetachment rate measurements . overall , agreement is found with the effective potential of an ideal 22-pole . however , in addition we observe 10 distinct minima in the trapping potential , which indicate a breaking of the 22-fold symmetry . numerical simulations show that a displacement of a subset of the radiofrequency electrodes can serve as an explanation for this symmetry breaking . . And you have already written the first three sentences of the full article: multipole radiofrequency ion traps @xcite , in particular the 22-pole ion trap @xcite , are versatile devices used in laser spectroscopy @xcite and investigations of chemical reaction processes @xcite of atomic and molecular ions . high order multipole traps offer a large field free region in the trap center , and therefore provide a reduced interaction time of the ions with the oscillating electric field compared to a quadrupole trap @xcite . buffer gas cooling down to cryogenic temperatures of the translational @xcite , rotational @xcite , and vibrational degrees of freedom @xcite of trapped molecular ions has been demonstrated .. Please generate the next two sentences of the article

this enables applications with all the advantages of low temperature experiments , such as a reduced doppler width in spectroscopy studies and a well defined population of internal states . stable confinement of a single ion in the oscillating quadrupole field of a paul trap is precisely predicted , because the mathieu equations of motion can be solved analytically .

Suppose that you have an abstract for a scientific paper: we study the local flow properties of various materials in a vane - in - cup geometry . we use mri techniques to measure velocities and particle concentrations in flowing newtonian fluid , yield stress fluid , and in a concentrated suspension of noncolloidal particles in a yield stress fluid . in the newtonian fluid , we observe that the @xmath0-averaged strain rate component @xmath1 decreases as the inverse squared radius in the gap , in agreement with a couette analogy . this allows direct comparison ( without end - effect corrections ) of the resistances to shear in vane and couette geometries . here , the mean shear stress in the vane - in - cup geometry is slightly lower than in a couette cell of same dimensions , and a little higher than when the vane is embedded in an infinite medium . we also observe that the flow enters deeply the region between the blades , leading to significant extensional flow . in the yield stress fluid , in contrast with the usually accepted picture based on simulation results from the literature , we find that the layer of material that is sheared near the blades at low velocity is not cylindrical . there is thus a significant extensional component of shear that should be taken into account in the analysis . finally and surprisingly , in the suspension , we observe that a thin non - cylindrical slip layer made of the pure interstitial yield stress fluid appears quickly at the interface between the sheared material and the material that moves as a rigid body between the blades . this feature can be attributed to the non - symmetric trajectories of the noncolloidal particles around the edges of the blades . this new important observation is in sharp contradiction with the common belief that the vane tool prevents slippage , and may preclude the use of the vane tool for studying the flows of pasty materials with large particles . . And you have already written the first three sentences of the full article: experimental investigations of the rheology of concentrated suspensions often involve a vane - in - cup geometry ( see @xcite for a review ) . the vane tool offers two main advantages over other geometries . first , it allows the study of the properties of structured materials with minimal disturbance of the material structure during the insertion of the tool [ @xcite ] .. Please generate the next two sentences of the article

it is thus widely used to study the properties of gels and thixotropic materials [ @xcite ] and for in situ study of materials as e.g. in the context of soil mechanics [ @xcite ] . second , it is supposed to avoid wall slip [ @xcite ] , which is a critical feature in concentrated suspensions [ @xcite ] ; the reason for this belief is that the material sheared in the gap of the geometry is sheared by the ( same ) material that is trapped between the blades .

Suppose that you have an abstract for a scientific paper: we present a theoretical study of the dissociative tunneling ionization process . analytic expressions for the nuclear kinetic energy distribution of the ionization rates are derived . a particularly simple expression for the spectrum is found by using the born - oppenheimer ( bo ) approximation in conjunction with the reflection principle . these spectra are compared to exact non - bo _ ab initio _ spectra obtained through model calculations with a quantum mechanical treatment of both the electronic and nuclear degrees freedom . in the regime where the bo approximation is applicable imaging of the bo nuclear wave function is demonstrated to be possible through reverse use of the reflection principle , when accounting appropriately for the electronic ionization rate . a qualitative difference between the exact and bo wave functions in the asymptotic region of large electronic distances is shown . additionally the behavior of the wave function across the turning line is seen to be reminiscent of light refraction . for weak fields , where the bo approximation does not apply , the weak - field asymptotic theory describes the spectrum accurately . . And you have already written the first three sentences of the full article: currently a number of intense mid - infrared light sources are being developed @xcite , spurred on by their uses in sub - attosecond pulse generation @xcite , strong - field holography @xcite and laser - induced electron diffraction @xcite . the low frequency and high intensity of these new sources mean that the tunneling picture is an appropriate framework for describing how these light sources interact with atoms and molecules . in this work we deal with the process of dissociative tunneling ionization in molecules , where a static electric field tunnel ionizes an electron , after which the nuclei dissociate . to our knowledge this is the first work on the theory of dissociative tunneling ionization . in the theory. Please generate the next two sentences of the article

we treat the nuclear and electronic degrees freedom on an equal footing and fully quantum mechanically . the reflection principle @xcite is often used to describe the process of dissociative ionization .

Suppose that you have an abstract for a scientific paper: the liouville - lanczos approach to linear - response time - dependent density - functional theory is generalized so as to encompass electron energy - loss and inelastic x - ray scattering spectroscopies in periodic solids . the computation of virtual orbitals and the manipulation of large matrices are avoided by adopting a representation of response orbitals borrowed from ( time - independent ) density - functional perturbation theory and a suitable lanczos recursion scheme . the latter allows the bulk of the numerical work to be performed at any given transferred momentum only once , for a whole extended frequency range . the numerical complexity of the method is thus greatly reduced , making the computation of the loss function over a wide frequency range at any given transferred momentum only slightly more expensive than a single standard ground - state calculation , and opening the way to computations for systems of unprecedented size and complexity . our method is validated on the paradigmatic examples of bulk silicon and aluminum , for which both experimental and theoretical results already exist in the literature . . And you have already written the first three sentences of the full article: plasma oscillations in solids are possibly the simplest manifestation of collective effects in condensed matter , and their understanding in terms of _ plasmon _ modes one of the earliest triumphs of quantum many - body theory . @xcite on the experimental side , collective charge - density fluctuations can be probed through electron energy - loss ( eel ) or inelastic x - ray scattering ( ixs ) spectroscopies , two techniques that have been steadily producing a wealth of data since the early 60s and 70s , respectively.@xcite in the present day the engineering of novel materials down to the nanometer scale makes it possible to design devices where electromagnetic fields interact with collective oscillations of structures of sub - wavelength size . the strong dependence of plasmon dynamics on the size and shape of these nanostructures holds the promise of an extraordinary control over the optical response of the resulting devices , with applications to such diverse fields as photovoltaics,@xcite proton beam acceleration,@xcite or biosensing,@xcite to name but a few .. Please generate the next two sentences of the article

this is plasmonics , _ i.e _ photonics based on collective electronic excitations in strongly heterogeneous systems , where surface effects play a fundamental role .

Suppose that you have an abstract for a scientific paper: in the framework of standard electrodynamics with linear local response , we construct a model that provides spontaneously broken transparency . the functional dependence of the medium parameter turns out to be of the higgs type . . And you have already written the first three sentences of the full article: physical models often involve phenomenological parameters or auxiliary fields characterizing the background spacetime or the background media . in most cases , dynamics of the model depend smoothly ( continuously and differentiably ) on the values of the background parameter . a non - smooth functional dependence is a rather rare phenomenon , but if it exists , it usually represents a keystone issue of the model . the examples of such non - smooth behavior are well known in solid state physics as phase transitions at critical points .. Please generate the next two sentences of the article

another similar issue is the scalar higgs model of spontaneous symmetry breaking . in this paper , we present a simple phenomenological model of an electromagnetic medium that allows wave propagation only for a sufficiently big value of the medium parameter . for zero values of the parameter ,

Suppose that you have an abstract for a scientific paper: we explicitly construct a particular real form of the lie algebra @xmath0 in terms of symplectic matrices over the octonions , thus justifying the identifications @xmath1 and , at the group level , @xmath2 . along the way , we provide a geometric description of the minimal representation of @xmath0 in terms of rank 3 objects called _ cubies_. . And you have already written the first three sentences of the full article: .the `` half - split '' @xmath3 magic square of lie algebras . [ cols="^,^,^,^,^",options="header " , ] an analogous problem has been analyzed for the @xmath4 magic square , which is shown in table [ 2x2 ] ; the interpretation of the first two rows was discussed in @xcite ; see also @xcite . dray , huerta , and kincaid showed first @xcite ( see also @xcite ) how to relate @xmath5 to @xmath6 , and later @xcite extended their treatment to the full @xmath4 magic square of lie groups in table [ 2x2 ] . in the third row , their clifford algebra description of @xmath7 is equivalent to a symplectic description as @xmath8 , with @xmath9 .. Please generate the next two sentences of the article

explicitly , they represent @xmath10 , where @xmath11 , in terms of actions on @xmath12 matrices of the form @xmath13 where @xmath14 is a @xmath4 hermitian matrix over @xmath15 , representing @xmath16 , @xmath17 , @xmath18 denotes the @xmath4 identity matrix , and tilde denotes trace - reversal , that is , @xmath19 . the matrix @xmath20 can be thought of as the upper right @xmath12 block of an @xmath21 clifford algebra representation , and the action of @xmath10 on @xmath20 is obtained as usual from ( the restriction of ) the quadratic elements of the clifford algebra .

Suppose that you have an abstract for a scientific paper: hot electron temperatures and electron energy spectra in the course of interaction between intense laser pulse and overdense plasmas are reexamined from a viewpoint of the difference in laser wavelength . the hot electron temperature measured by a particle - in - cell simulation is scaled by @xmath0 rather than @xmath1 at the interaction with overdense plasmas with fixed ions , where @xmath0 and @xmath2 are the laser intensity and wavelength , respectively . . And you have already written the first three sentences of the full article: the interaction of intense laser pulses with overdense plasmas has attracted much interest for the fast ignitor concept in inertial fusion energy @xcite . the interaction of ultrashort intense laser pulses with thin solid targets have also been of great interest for the application to high energy ion sources @xcite . ultraintense irradiation experiments using an infrared subpicosecond laser , e.g. , nd : glass ( @xmath3 1,053 nm ) or ti : sapphire ( @xmath3800 nm ) lasers , whose powers and focused intensities exceed 100 tw and @xmath4 w/@xmath5 , are possible using chirped pulse amplification techniques @xcite . in these experiments , the classical normalized momentum of electrons @xmath6 , where @xmath7 is the electron mass , @xmath8 is the speed of light , @xmath0 is the laser intensity in w/@xmath5 , and @xmath9 is the wavelength in @xmath10 m . on the other hand ,. Please generate the next two sentences of the article

a krf laser ( @xmath3 248 nm ) has an advantage as the fast ignitor in that the critical density is close to the core , and hot electron energies are suitable since the critical density of the krf laser is ten times greater than that of an infrared laser @xcite . the peak intensities of krf laser systems were only the order of @xmath11 w/@xmath5 , namely @xmath12 @xcite .

Suppose that you have an abstract for a scientific paper: a method is presented to obtain the canonical - form solutions of the hfb equation for atomic nuclei with zero - range interactions like the skyrme force . it is appropriate to describe pairing correlations in the continuum in coordinate - space representations . an improved gradient method is used for faster convergences under constraint of orthogonality between orbitals . to prevent high - lying orbitals to shrink into a spatial point , a repulsive momentum dependent force is introduced , which turns out to unveil the nature of high - lying canonical - basis orbitals . the asymptotic properties at large radius and the relation with quasiparticle states are discussed for the obtained canonical basis . . And you have already written the first three sentences of the full article: pairing correlations play an essential role in the determination of the ground - state structure of the vast majority of atomic nuclei . among its treatments , an easy but still enough accurate one is to consider only single - particle states near the fermi level while the effects of the other states are assumed to be absorbed in the strength of an effective pairing interaction . in such a treatment , our experiences in hartree - fock(hf)+bcs calculations suggest that at least half of a major shell above the fermi level must be considered for meaningful estimations . as a consequence. Please generate the next two sentences of the article

, one has to explicitly consider positive - energy states if the fermi level of neutrons is higher than the negative of half of the major shell spacing ( @xmath0 mev ) . this condition applies to about half of the @xmath1 nuclides which exist between proton and neutron drip lines in the nuclear chart , not only to nuclei near the neutron drip line or outside the s - process path .

Suppose that you have an abstract for a scientific paper: it is believed that orphan afterglow searches can help to measure the beaming angle in gamma - ray bursts ( grbs ) . great expectations have been put on this method . we point out that the method is in fact not as simple as we originally expected . due to the baryon - rich environment that is common to almost all popular progenitor models , there should be many failed gamma - ray bursts , i.e. , fireballs with lorentz factor much less than 100 1000 , but still much larger than unity . in fact , the number of failed gamma - ray bursts may even be much larger than that of successful bursts . owing to the existence of these failed gamma - ray bursts , there should be many orphan afterglows even if grbs are due to isotropic fireballs , then the simple discovery of orphan afterglows never means that grbs be collimated . unfortunately , to distinguish a failed - grb orphan and a jetted but off - axis grb orphan is not an easy task . the major problem is that the trigger time is unknown . some possible solutions to the problem are suggested . = -0.5 in stars : neutron ism : jets and outflows gamma - rays : bursts . And you have already written the first three sentences of the full article: the detection of x - ray , optical and radio afterglows from some well - localized gamma - ray bursts ( grbs ) definitely shows that at least most long grbs are of cosmological origin ( e.g. , costa et al . 1997 ; frail et al . 1997 ; galama et al . 1998 ; akerlof et al . 1999 ; zhu et al . 1999 ) . the so called fireball model is thus strongly favoured .. Please generate the next two sentences of the article

however , we are still far from resolving the puzzle of grbs ( piran 1999 ; van paradijs , kouveliotou & wijers 2000 ) . a major problem is that we do not know whether grbs are due to highly collimated jets or isotropic fireballs , so that the energetics involved can not be determined definitely ( e.g. , pugliese , falcke & biermann 1999 ; kumar & piran 2000 ; dar & rjula 2000 ; wang & loeb 2001 ; rossi , lazzati & rees 2002 ) .

Suppose that you have an abstract for a scientific paper: we consider the dynamics of a movable mirror ( cantilever ) of a nonlinear optical cavity . we show that a @xmath0 medium with a strong kerr nonlinearity placed inside a cavity inhibits the normal mode splitting ( nms ) due to the photon blockade mechanism . this study demonstrates that nms could be used as a tool to observe the photon blockade effect . we also found that the backaction cooling of the movable mirror is reduced in the presence of the kerr medium . . And you have already written the first three sentences of the full article: the interaction between a movable mirror and the radiation field of an optical cavity has recently been the subject of extensive theoretical and experimental investigations . these optomechanical systems couple the mechanical motion to an optical field directly via radiation pressure buildup in a cavity . the coupling of mechanical and optical degrees of freedom via radiation pressure has been a subject of early research in the context of laser cooling @xcite and gravitational - wave detectors @xcite . recently there has been a great surge of interest in the application of radiation forces to manipulate the center - of - mass motion of mechanical oscillators covering a huge range of scales from macroscopic mirrors in the laser interferometer gravitational wave observatory ( ligo ) project @xcite to nano - mechanical cantilevers@xcite , vibrating microtoroids@xcite membranes@xcite and bose - einstein condensates @xcite .. Please generate the next two sentences of the article

the quantum optical properties of a mirror coupled via radiation pressure to a cavity field show interesting similarities to an intracavity kerr - like interaction @xcite . recently , in the context of classical investigations of nonlinear regimes , the dynamical instability of a driven cavity having a movable mirror has been investigated @xcite .

Suppose that you have an abstract for a scientific paper: we consider the supersymmetric extension of the standard model with neutrino yukawa interactions and @xmath0-parity violation . we found that @xmath0-parity breaking term @xmath1 leads to an additional @xmath2-type contribution to the higgs scalar potential , and thus to the masses of supersymmetric higgs bosons . the most interesting consequence is the modification of the tree - level expression for the lightest neutral supersymmetric higgs boson mass . it appears that due to this contribution the bound on the lightest higgs mass may be shifted upwards , thus slightly opening the part of the model parameter space excluded by non - observation of the light higgs boson at lep in the framework of the minimal supersymmetric standard model . . And you have already written the first three sentences of the full article: the searches for the higgs boson and new phenomena beyond the standard model of fundumental interactions are important tasks for the new particle accelerator the large hadron collider . the most popular direction beyond the sm is low energy supersymmetry . however , it is not clear how supersymmetry is realized . the simplest case the minimal supersymmetric standard model ( mssm)@xcite is studied in detailes , however possible deviations from it are of great interest as well .. Please generate the next two sentences of the article

there exists a wide class of models which contain so called @xmath0-parity breaking interactions leading to the violation of lepton and baryon numbers@xcite . these models have a number of new coupling constants , some of them are badly constrained , for instance , by rare processes , other ones are less restricted .

Suppose that you have an abstract for a scientific paper: two numerical strategies based on the wang - landau and lee entropic sampling schemes are implemented to investigate the first - order transition features of the 3d bimodal ( @xmath0 ) random - field ising model at the strong disorder regime . we consider simple cubic lattices with linear sizes in the range @xmath1 and simulate the system for two values of the disorder strength : @xmath2 and @xmath3 . the nature of the transition is elucidated by applying the lee - kosterlitz free - energy barrier method . our results indicate that , despite the strong first - order - like characteristics , the transition remains continuous , in disagreement with the early mean - field theory prediction of a tricritical point at high values of the random - field . _ keywords _ : bimodal random - field ising model , wang - landau sampling , free - energy barrier method . And you have already written the first three sentences of the full article: the random - field ising model ( rfim ) @xcite has been extensively studied both because of its interest as a simple frustrated system and because of its relevance to experiments @xcite . the hamiltonian describing the model is @xmath4 where @xmath5 are ising spins , @xmath6 is the nearest - neighbors ferromagnetic interaction , @xmath7 is the disorder strength , also called randomness of the system , and @xmath8 are independent quenched random - fields ( rf s ) obtained here from a bimodal distribution of the form @xmath9.\ ] ] various rf probability distributions , such as the gaussian , the wide bimodal distribution ( with a gaussian width ) , and the above bimodal distribution have been considered @xcite . as it is well known , the existence of an ordered ferromagnetic phase for the rfim , at low temperature and weak disorder , follows from the seminal discussion of imry and ma @xcite , when @xmath10 .. Please generate the next two sentences of the article

this has provided us with a general qualitative agreement on the sketch of the phase boundary separating the ordered ferromagnetic ( * f * ) phase from the high - temperature paramagnetic ( * p * ) phase . a sketch of the phase boundary of the 3d bimodal rfim , where @xmath11 is the critical disorder strength and @xmath12 the critical temperature of the pure 3d ising model . the question - mark refers to the mean - field prediction of a tricritical point ( tcp ) , where the transition supposedly changes from second - order at low - fields ( solid line ) to first - order at high - fields ( dotted line).,width=12 ] the phase boundary ( see figure [ fig:1 ] ) separates the two phases of the model and intersects the randomness axis at the critical value of the disorder strength @xmath11 .

Suppose that you have an abstract for a scientific paper: extensive time - resolved observations of kuiper belt object 2001 qg@xmath0 show a lightcurve with a peak - to - peak variation of @xmath1 magnitudes and single - peaked period of @xmath2 hr . the mean absolute magnitude is 6.85 magnitudes which corresponds to a mean effective radius of 122 ( 77 ) km if an albedo of 0.04 ( 0.10 ) is assumed . this is the first known kuiper belt object and only the third minor planet with a radius @xmath3 25 km to display a lightcurve with a range in excess of 1 magnitude . we find the colors to be typical for a kuiper belt object ( @xmath4 , @xmath5 ) with no variation in color between minimum and maximum light . the large light variation , relatively long double - peaked period and absence of rotational color change argue against explanations due to albedo markings or elongation due to high angular momentum . instead , we suggest that 2001 qg@xmath0 may be a very close or contact binary similar in structure to what has been independently proposed for the trojan asteroid 624 hektor . if so , its rotational period would be twice the lightcurve period or @xmath6 hr . by correcting for the effects of projection , we estimate that the fraction of similar objects in the kuiper belt is at least @xmath710% to 20% with the true fraction probably much higher . a high abundance of close and contact binaries is expected in some scenarios for the evolution of binary kuiper belt objects . . And you have already written the first three sentences of the full article: the kuiper belt is a long - lived region of the solar system just beyond neptune where the planetisimals have not coalesced into a planet . it contains about 80,000 objects with radii greater than 50 km ( trujillo , jewitt & luu 2001 ) which have been collisionally processed and gravitationally perturbed throughout the age of the solar system . the short - period comets and centaurs are believed to originate from the kuiper belt ( fernandez 1980 ; duncan , quinn & tremaine 1988 ) . physically , the kuiper belt objects ( kbos ) show a large diversity of colors from slightly blue to ultra red ( @xmath8 to @xmath9 , luu and jewitt 1996 ) and may show correlations between colors , inclination and/or perihelion distance ( jewitt & luu 2001 ; trujillo & brown 2002 ; doressoundiram et al . 2002 ; tegler & romanishin 2003 ) .. Please generate the next two sentences of the article

spectra of kbos are mostly featureless with a few showing hints of water ice ( brown , cruikshank & pendleton 1999 ; jewitt & luu 2001 ; lazzarin et al . the range of kbo geometric albedos is still poorly sampled but the larger ones likely have values between 0.04 to 0.10 ( jewitt , aussel & evans 2001 ; altenhoff , bertoldi & menten 2004 ) .

Suppose that you have an abstract for a scientific paper: we generalize the classical one dimensional potts model to the case where the symmetry group is a non - abelian finite group . it turns out that this new model has a quantum nature in that its spectrum of energy eigenstates consists of entangled states . we determine the complete energy spectrum , i.e. the ground states and all the excited states with their degeneracy structure . we calculate the partition function by two different algebraic and combinatorial methods . we also determine the entanglement properties of its ground states . * the quantum ( non - abelian ) potts model and its exact solution * 4em * razieh mohseninia * and * vahid karimipour * 1em department of physics , + sharif university of technology , p.o . box 111555 - 9161 , tehran , iran . + pacs numbers : 05.50.+q , 64.60.de , 75.10.-b , 75.10.hk , 03.65.ud . And you have already written the first three sentences of the full article: the ising model is a prototype of a statistical mechanical model for studying order - disorder transitions . it is also the first statistical model which has led to exact solution in one and two dimensions . since its inception@xcite this model has triggered an intense effort in investigation of other models resulting in an extensive literature on the subject @xcite .. Please generate the next two sentences of the article

there are now a large library of statistical and quantum mechanical models , differing in their degrees of freedom , interaction type , the type and dimensions of lattices , and of course methods of solution @xcite . there are also models which can be called integrable , meaning that they allow sufficient number of conserved quantities , leading to a full determination of their spectra and other observable quantities . among the well - known classical models

Suppose that you have an abstract for a scientific paper: the scaling of the tails of the probability of a system to percolate only in the horizontal direction @xmath0 was investigated numerically for correlated site - bond percolation model for @xmath1 . we have to demonstrate that the tails of the crossing probability far from the critical point @xmath2 have shape @xmath3^{\nu})$ ] where @xmath4 is the correlation length index , @xmath5 is the probability of a bond to be closed . at criticality we observe crossover to another scaling @xmath6^{\nu } \right\}^{z } \right)$ ] . here @xmath7 is a scaling index describing the central part of the crossing probability . . And you have already written the first three sentences of the full article: the @xmath8-state potts model can be represented as the correlated site - bond percolation in terms of fortuin - kasteleyn clusters @xcite . at the critical point of the second order phase transition , the infinite cluster is formed . this cluster crosses the system connecting the opposite sides of the square lattice . in the last decade. Please generate the next two sentences of the article

the study of the shape of the crossing probability was performed by conformal methods @xcite as well as numerically @xcite . according to refs . @xcite the distribution function of the percolation thresholds is gaussian function . following the number of works @xcite

Suppose that you have an abstract for a scientific paper: we have obtained optical spectra of 29 early - type ( e / s0 ) galaxies that hosted type ia supernovae ( sne ia ) . we have measured absorption - line strengths and compared them to a grid of models to extract the relations between the supernova properties and the luminosity - weighted age / composition of the host galaxies . such a direct measurement is a marked improvement over existing analyses which tend to rely on general correlations between the properties of stellar populations and morphology . our galaxy sample ranges over a factor of ten in iron abundance and shows both old and young dominant population ages . the same analysis was applied to a large number of early - type field galaxies selected from the sdss spectroscopic survey . we find no difference in the age and abundance distributions between the field galaxies and the sn ia host galaxies . we do find a strong correlation suggesting that sne ia in galaxies whose populations have a characteristic age greater than 5 gyr are @xmath0 1 mag fainter at @xmath1 than those found in galaxies with younger populations . however , the data can not discriminate between a smooth relation connecting age and supernova luminosity or two populations of sn ia progenitors . we find that sn ia distance residuals in the hubble diagram are correlated with host - galaxy metal abundance , consistent with the predictions of @xcite . the data show that high iron abundance galaxies host less - luminous supernovae . we thus conclude that the time since progenitor formation primarily determines the radioactive ni production while progenitor metal abundance has a weaker influence on peak luminosity , but one not fully corrected by light - curve shape and color fitters . this result , particularly the secondary dependence on metallicity , has significant implications for the determination of the equation - of - state parameter , @xmath2 , and could impact planning for future dark - energy missions such as jdem . assuming no selection.... And you have already written the first three sentences of the full article: type ia supernovae ( sne ia ) have proven to be effective standardizable candles and their high peak luminosity has made them excellent cosmological probes . an empirically determined relation between light - curve properties and peak absolute magnitude @xcite has yielded improved estimates of the global hubble constant @xcite . although the earliest attempts to measure the matter density of the universe preceded these light - curve shape methods @xcite , and the initial efforts by the supernova cosmology project ( scp ) led to incorrect conclusions about the cosmic matter density @xcite , early work by both the scp and the high - z supernova search team @xcite found evidence for low matter density @xcite . subsequent publications by @xcite and @xcite came to the surprising conclusion that the universe is expanding at an accelerating rate , driven by a mysterious dark energy ; see @xcite , @xcite , or @xcite for reviews .. Please generate the next two sentences of the article

this surprising result has been confirmed by more - recent supernova observations @xcite and by complementary measurements of the cosmic microwave background ( cmb ) anisotropies ( e.g. , * ? ? ? * ) and large - scale structure ( e.g. , * ? ? ? focus has now shifted from demonstrating the existence of dark energy to constraining its properties @xcite and sharpening the tools available for its study ( e.g. , * ? ? ?

Suppose that you have an abstract for a scientific paper: in this paper , we extend previous work on the absorption of high energy @xmath0-rays in intergalactic space by calculating the absorption of 10 to 500 gev @xmath0-rays at high redshifts . this calculation requires the determination of the high - redshift evolution of the intergalactic starlight photon field , including its spectral energy distribution out to frequencies beyond the lyman limit . to estimate this evolution , we have followed a recent analysis of fall , charlot & pei , which reproduces the redshift dependence of the starlight background emissivity obtained by the canada - france redshift survey group . we also include the uv background from quasars . we give our results for the @xmath0-ray opacity as a function of redshift out to a redshift of 3 . we also give predicted @xmath0-ray spectra for selected blazars and extend our calculations of the extragalactic @xmath0-ray background from blazars to an energy of 500 gev with absorption effects included . our results indicate that the extragalactic @xmath0-ray background spectrum from blazars should steepen significantly above 20 gev , owing to extragalactic absorption . future observations of a such a steepening would thus provide a test of the blazar origin hypothesis for the @xmath0-ray background radiation . we also note that our absorption calculations can be used to place limits on the redshifts of @xmath0-ray bursts ; for example , our calculated opacities indicate that the 17 feb . 1994 burst observed by _ egret _ must have originated at @xmath1 . finally , our estimates of the high - energy @xmath0-ray background spectrum are used to determine the observability of multi - gev @xmath0-ray lines from the annihilation of supersymmetric dark - matter particles in the galactic halo . . And you have already written the first three sentences of the full article: the _ egret _ experiment aboard the _ compton gamma ray observatory _ has detected more than 50 blazars extending out to redshifts greater than 2 ( thompson , _ et al . _ it is expected that @xmath0-rays from blazars with energies above the threshold energy for electron - positron pair production through interactions with low energy intergalactic photons will be annihilated , cutting off the high energy end of blazar spectra . such absorption is strongly dependent on the redshift of the source ( stecker , de jager & salamon 1992 ) .. Please generate the next two sentences of the article

stecker & de jager ( 1997 ) have calculated the absorption of extragalactic @xmath0-rays above 0.3 tev at redshifts up to 0.54 and presented a comparison with the spectral data for the low redshift blazar mrk 421 . the study of blazar spectra at energies below 0.3 tev is a more complex and physically interesting subject .

Suppose that you have an abstract for a scientific paper: we present the _ xmm - newton _ observations of x - ray afterglows of the @xmath0-ray bursts grb 011211 and grb 001025 . for grb 011211 _ xmm _ detected fading x - ray object with an average flux in 0.2 - 10 kev declining from @xmath1 erg @xmath2 s@xmath3 during the first 5 ks of 27-ks observation to @xmath4 erg @xmath2 s@xmath3 toward the end of the observation . the spectrum of the afterglow can be fit to a power law with @xmath5=2.16@xmath60.03 modified for the galactic absorption . no significant evolution of spectral parameters has been detected during the observation . similar x - ray spectrum with @xmath5=2.01@xmath60.09 has been observed by the xmm from the grb 001025 . the non - detection of any extra absorption in these spectra above the galactic value is an interesting fact and may impose restrictions to the favorable grb models involving burst origin in star - forming regions . finally we discuss soft x - ray lines from grb 011211 reported by reeves et al . and conclude that there is no definitive evidence for the presense of these lines in the spectrum . * # 1#1 . And you have already written the first three sentences of the full article: cosmic bursts of gamma - rays are some of the most elusive and mysterious events in the universe . typical burst lasts less than a minute and disappears thereafter . however , since the _ bepposax _ s first discovery on 1997 february 28 ( costa et al . 1997 ) it is known that gamma - ray bursts ( grbs ) also produce x - ray afterglows , which can be detected with modern x - ray observatories for several hours and sometimes several days after the burst . more than a few x - ray afterglows have been observed in last five years by _ bepposax , asca and chandra _ satellites .. Please generate the next two sentences of the article

several afterglow observations were carried out with _ xmm - newton_. in this _ letter _ we report on two of the latter observations .

Suppose that you have an abstract for a scientific paper: transport measurements were performed on the organic layered compound 3 under hydrostatic pressure . the carrier types , densities and mobilities are determined from the magneto - conductance of 3 . while evidence of high - mobility massless dirac carriers has already been given , we report here , their coexistence with low - mobility massive holes . this coexistence seems robust as it has been found up to the highest studied pressure . our results are in agreement with recent dft calculations of the band structure of this system under hydrostatic pressure . a comparison with graphene dirac carriers has also been done . 3 @xmath0 2 @xmath1 . And you have already written the first three sentences of the full article: the layered organic material 3 ( ai3 ) , which has been studied since the 1980s,@xcite has recently attracted renewed interest because it reveals low - energy massless dirac fermions under hyrdostatic pressure ( @xmath2 gpa).@xcite compared to graphene , certainly the most popular material with low - energy dirac fermions@xcite or electronic states at the surface of three - dimensional topological insulators,@xcite ai3 is strikingly different in several respects . apart from the tilt of the dirac cones and the anisotropy in the fermi surface,@xcite its average fermi velocity is roughly one order of magnitude smaller than that in graphene . this , together with an experimentally identified low - temperature charge - ordered phase at ambient pressure,@xcite indicates the relevance of electronic correlations .. Please generate the next two sentences of the article

indeed , because the effective coupling constant for coulomb - type electron - electron interactions is inversely proportional to the fermi velocity , it is expected to be ten times larger in ai3 than in graphene . the material ai3 thus opens the exciting prospective to study strongly - correlated dirac fermions that are beyond the scope of graphene electrons.@xcite .

Suppose that you have an abstract for a scientific paper: we discuss some of our current knowledge of the mass distribution of da and non - da stars using various methods for measuring white dwarf masses including spectroscopic , trigonometric parallax , and gravitational redshift measurements , with a particular emphasis on the problems encountered at the low end of the cooling sequence where energy transport by convection becomes important . . And you have already written the first three sentences of the full article: the unwavering obsession to which the title refers applies only to the first author since the other co - authors are still too young to be obsessed by such a thing as the mass distribution of white dwarf stars . as early as 1976 , it was suggested that below @xmath0 k , convective mixing between the thin superficial hydrogen layer and the more massive underlying helium layer could turn a hydrogen - rich star into a helium - rich star , provided the mass of the hydrogen layer is small enough ( a modern value yields @xmath1 ) . furthermore , the effective temperature at which this mixing occurs is a function of the mass of the hydrogen layer : for thicker hydrogen layers , the mixing occurs at lower effective temperatures .. Please generate the next two sentences of the article

since the process of convective mixing is still poorly understood , the exact ratio of helium to hydrogen after the mixing occurs remains unknown . in particular , it is possible that instead of turning a da star into a featureless helium - rich dc star , convective mixing may simply enrich the hydrogen - rich atmosphere with large quantities of helium , leading to a mixed hydrogen and helium atmospheric composition .

Suppose that you have an abstract for a scientific paper: we study a two - point self - avoidance energy @xmath0 which is defined for all rectifiable curves in @xmath1 as the double integral along the curve of @xmath2 . here @xmath3 stands for the radius of the ( smallest ) circle that is tangent to the curve at one point and passes through another point on the curve , with obvious natural modifications of this definition in the exceptional , non - generic cases . it turns out that finiteness of @xmath4 for @xmath5 guarantees that @xmath6 has no self - intersections or triple junctions and therefore must be homeomorphic to the unit circle @xmath7 or to a closed interval @xmath8 . for @xmath9 the energy @xmath0 evaluated on curves in @xmath10 turns out to be a knot energy separating different knot types by infinite energy barriers and bounding the number of knot types below a given energy value . we also establish an explicit upper bound on the hausdorff - distance of two curves in @xmath10 with finite @xmath0-energy that guarantees that these curves are ambient isotopic . this bound depends only on @xmath11 and the energy values of the curves . moreover , for all @xmath11 that are larger than the critical exponent @xmath12 , the arclength parametrization of @xmath6 is of class @xmath13 , with hlder norm of the unit tangent depending only on @xmath11 , the length of @xmath6 , and the local energy . the exponent @xmath14 is optimal . . And you have already written the first three sentences of the full article: imagine a space craft travelling with constant speed along an unknown and possibly quite irregular closed path @xmath15 in an unexplored territory of the universe . after some time @xmath16 the loop is completed at least once , and the only data the astronauts can measure at time @xmath17 are the ratios of the squared distance from any previous position @xmath18 , to the distance of the current line of direction @xmath19 from that previous position @xmath18 , i.e. , the quotients @xmath20\quad{\,\,\,\text{for } \,\,}s < t.\ ] ] what can the astronauts say about their path of travel ? in other words , how much information about a closed curve of finite length in euclidean space is encoded in the relative tangent - point data ?. Please generate the next two sentences of the article

the answer is : if the astronauts obtain a finite integral mean of some inverse power of all these data ( after time @xmath21 ) they can extract essential topological information as well as explicit smoothness properties of their path of travel ! to make this precise we assume from now on that the path @xmath22 is a rectifiable curve of finite length , parametrized by arclength on the circle @xmath23 of perimeter @xmath24 . hence , @xmath15 is a ( not necessarily injective ) lipschitz continuous mapping with @xmath25 a.e . on @xmath26 .

Suppose that you have an abstract for a scientific paper: we consider transport diffusion in a stochastic billiard in a random tube which is elongated in the direction of the first coordinate ( the tube axis ) . inside the random tube , which is stationary and ergodic , non - interacting particles move straight with constant speed . upon hitting the tube walls , they are reflected randomly , according to the cosine law : the density of the outgoing direction is proportional to the cosine of the angle between this direction and the normal vector . steady state transport is studied by introducing an open tube segment as follows : we cut out a large finite segment of the tube with segment boundaries perpendicular to the tube axis . particles which leave this piece through the segment boundaries disappear from the system . through stationary injection of particles at one boundary of the segment a steady state with non - vanishing stationary particle current is maintained . we prove ( i ) that in the thermodynamic limit of an infinite open piece the coarse - grained density profile inside the segment is linear , and ( ii ) that the transport diffusion coefficient obtained from the ratio of stationary current and effective boundary density gradient equals the diffusion coefficient of a tagged particle in an infinite tube . thus we prove fick s law and equality of transport diffusion and self - diffusion coefficients for quite generic rough ( random ) tubes . we also study some properties of the crossing time and compute the milne extrapolation length in dependence on the shape of the random tube . + * keywords : * cosine law , knudsen random walk , random medium , self - diffusion coefficient , transport diffusion coefficient , random walk in random environment + * ams 2000 subject classifications : * 60k37 . secondary : 37d50 , 60j25 @xmath0universit paris 7 , ufr de mathmatiques , case 7012 , 2 , place jussieu , f75251 paris cedex 05 , france + e - mail : ` comets@math.jussieu.fr ` , url : ` http://www.proba.jussieu.fr/\simcomets ` .... And you have already written the first three sentences of the full article: diffusion in stationary states may be encountered either in equilibrium , where no macroscopic mass or energy fluxes are present in a system of many diffusing particles , or away from equilibrium , where diffusion is often driven by a density gradient between two open segments of the surface that encloses the space in which particles diffuse . in equilibrium states , one is interested in the _ self - diffusion _ coefficient @xmath3 , as given by the mean - square displacement ( msd ) of a tagged particle .. Please generate the next two sentences of the article

this quantity , also called tracer diffusion coefficient , can be measured using e.g. neutron scattering , nmr or direct video imaging in the case of colloidal particles . in gradient - driven non - equilibrium steady states , there is a particle flux between the boundaries which is proportional to the density gradient .

Suppose that you have an abstract for a scientific paper: we construct effective 2- and 3-body hamiltonians for the p - shell by performing @xmath0 _ ab initio _ no - core shell model ( ncsm ) calculations for a=6 and 7 nuclei and explicitly projecting the many - body hamiltonians onto the @xmath1 space . we then separate these effective hamiltonians into 0- , 1- and 2-body contributions ( also 3-body for a=7 ) and analyze the systematic behavior of these different parts as a function of the mass number a and size of the ncsm basis space . the role of effective 3- and higher - body interactions for @xmath2 is investigated and discussed . . And you have already written the first three sentences of the full article: microscopic _ ab - initio _ many - body approaches have significantly progressed in recent years @xcite . nowdays , due to increased computing power and novel techniques , _ ab - initio _ calculations are able to reproduce a large number of observables for atomic nuclei with mass up to a=14 . the light nuclei have also served as a crucial site to recognize the important role of three - body forces and three - body correlations .. Please generate the next two sentences of the article

approaches like the no - core shell model ( ncsm ) @xcite , the green s function monte carlo ( gfmc ) @xcite and the coupled - cluster theory with single and double excitations ( ccsd ) @xcite can be formally extended for heavier nuclei . however , the explosive growth in computational power , required to achieve convergent results , severely hinders the detailed _ ab - initio _ studies of heavier , a@xmath3 , nuclei . in the case of the ncsm ,

Suppose that you have an abstract for a scientific paper: we prove algebraic analogues of the facts that a curve on a surface with self - intersection number zero is homotopic to a cover of a simple curve , and that two simple curves on a surface with intersection number zero can be isotoped to be disjoint . in this paper , we will discuss an algebraic version of intersection numbers which was introduced by scott in @xcite . first we need to discuss intersection numbers in the topological setting . let @xmath0 denote a surface and let @xmath1 and @xmath2 each be a properly immersed two - sided circle or compact arc in @xmath0 . here ` properly ' means that the boundary of the @xmath3manifold lies in the boundary of @xmath0 . one can define the intersection number of @xmath1 and @xmath2 to be the least number of intersection points obtainable by homotoping @xmath1 and @xmath2 transverse to each other . ( the count is to be made without any signs attached to the intersection points . ) it is obvious that this number is symmetric in the sense that it is independent of the order of @xmath1 and @xmath2 . it is also obvious that @xmath1 and @xmath2 have intersection number zero if and only if they can be properly homotoped to be disjoint . it seems natural to define the self - intersection number of an immersed two - sided circle or arc @xmath1 in @xmath0 to be the least number of transverse intersection points obtainable by homotoping @xmath1 into general position . with this definition , @xmath1 has self - intersection number zero if and only if it is homotopic to an embedding . however , in light of later generalisations , it turns out that this definition should be modified a little in order to ensure that the self - intersection number of any cover of a simple closed curve is also zero . no modification is needed unless @xmath1 is a circle which can be homotoped to cover another immersion with degree greater than @xmath3 . in this case , suppose that the maximal degree of covering which can occur is @xmath4 and that @xmath1 covers @xmath5.... And you have already written the first three sentences of the full article: we will start by recalling from @xcite how to define intersection numbers in the algebraic setting . we will connect this with the natural topological idea of intersection number already discussed in the introduction . consider two simple closed curves @xmath1 and @xmath2 on a closed orientable surface @xmath0 . as in @xcite , it will be convenient to assume that @xmath1 and @xmath2 are shortest geodesics in some riemannian metric on @xmath0 so that they automatically intersect minimally .. Please generate the next two sentences of the article

we will interpret the intersection number of @xmath1 and @xmath2 in suitable covers of @xmath28 , exactly as in @xcite and @xcite . let @xmath12 denote @xmath29 , let @xmath13 denote the infinite cyclic subgroup of @xmath12 carried by @xmath1 , and let @xmath30 denote the cover of @xmath0 with fundamental group equal to @xmath13 .

Suppose that you have an abstract for a scientific paper: for sequences of random backward nested subspaces as occur , say , in dimension reduction for manifold or stratified space valued data , asymptotic results are derived . in fact , we formulate our results more generally for backward nested families of descriptors ( bnfd ) . under rather general conditions , asymptotic strong consistency holds . under additional , still rather general hypotheses , among them existence of a.s . local twice differentiable charts , asymptotic joint normality of a bnfd can be shown . if charts factor suitably , this leads to individual asymptotic normality for the last element , a principal nested mean or a principal nested geodesic , say . it turns out that these results pertain to principal nested spheres ( pns ) and principal nested great subsphere ( pngs ) analysis by @xcite as well as to the intrinsic mean on a first geodesic principal component ( imo1gpc ) for manifolds and kendall s shape spaces . a nested bootstrap two - sample test is derived and illustrated with simulations . in a study on real data , pngs is applied to track early human mesenchymal stem cell differentiation over a coarse time grid and , among others , to locate a change point with direct consequences for the design of further studies . _ keywords : _ frchet means , dimension reduction on manifolds , principal nested spheres , asymptotic consistency and normality , geodesic principal component analysis , kendall s shape spaces , flags of subspaces _ ams subject classifications : _ primary 62g20 , 62g25 . secondary 62h11 , 58c06 , 60d05 . . And you have already written the first three sentences of the full article: in this paper , the novel statistical problem of deriving asymptotic results for nested random sequences of statistical descriptors for data in a non - euclidean space is considered . it can be viewed as a generalization of classical pca s asymptotics , e.g. by @xcite , where , as a consequence of pythagoras theorem , nestedness of approximating subspaces is trivially given and thus requires no special attention . for pca analogs for data in non - euclidean spaces , due to curvature , nestedness considerably complicates design of descriptors and , to the best knowledge of the authors , has hindered any asymptotic theory to date . for dimension reduction of non - euclidean data ,. Please generate the next two sentences of the article

_ procrustes analysis _ by @xcite and later _ principal geodesic analysis _ by @xcite are approaches to mimic pca on shape spaces and riemannian manifolds , respectively . both build on the concept of a frchet mean , a minimizer of expected squared distance , around which classical pca is conducted for the data mapped to a suitable tangent space .

Suppose that you have an abstract for a scientific paper: we report the results of a systematic near - infrared spectroscopic survey using the subaru , vlt and keck telescopes of a sample of high redshift ultra - luminous infrared galaxies ( ulirgs ) mainly composed of submillimeter - selected galaxies . our observations span the restframe optical range containing nebular emission lines such as h@xmath0 , [ oiii]@xmath1 , and [ oii]@xmath2 , which are essential for making robust diagnostics of the physical properties of these ulirgs . using the h@xmath3/h@xmath0 emission line ratios , we derive internal extinction estimates for these galaxies similar to those of local ulirgs : @xmath4 . correcting the h@xmath3 estimates of the star formation rate for dust extinction using the balmer decrement , results in rates which are consistent with those estimated from the far - infrared luminosity . the majority ( @xmath5% ) of our sample show spectral features characteristic of agn ( although we note this partially reflects an observational bias in our sample ) , with @xmath6% exhibiting broad balmer emission lines . a proportion of these sources show relatively low [ oiii]@xmath7/h@xmath0 line ratios , which are similar to those of narrow line seyfert 1 galaxies suggesting small mass black holes which are rapidly growing . in the subsample of our survey with both [ oiii]@xmath7 and hard x - ray coverage , at least @xmath8% show an excess of [ oiii]@xmath7 emission , by a factor of 510@xmath9 , relative to the hard x - ray luminosity compared to the correlation between these two properties seen in seyferts and qsos locally . from our spectral diagnostics , we propose that the strong [ oiii]@xmath7 emission in these galaxies arises from shocks in dense gaseous regions in this vigorously star - forming population . we caution that due to sensitivity and resolution limits , our sample is biased to strong line emitters and hence our results do not yet provide a complete view of the physical properties of the whole high - redshift ulirg population . . And you have already written the first three sentences of the full article: there is almost irrefutible evidence for an increase in the star formation density with redshift , as demonstrated by emission line and continuum star formations tracers in wavebands from the ultraviolet to the submillimeter and radio wavebands . this evolution appears to be stronger for tracers which are less sensitive to dust obscuration ( e.g. ivison et al . 2006 ) , suggesting that an increasing proportion of the activity in more distant galaxies may be highly obscured ( e.g. blain et al . 1999 , 2002 ) .. Please generate the next two sentences of the article

indeed , recent results on the mid- to far - infrared emission of luminous but dust obscured galaxies at high redshift ( @xmath103 ) suggests that the origin of their large infrared luminosities is a mix of dust obscured vigorous star formation and/or dust enshrouded active galactic nucleus ( agn ) ( yan et al . 2005 ; houck et al . 2005 ; lutz et al . 2005 ; desai et al.2006 ) .

Suppose that you have an abstract for a scientific paper: steganography is an information hiding application which aims to hide secret data imperceptibly into a commonly used media . unfortunately , the theoretical hiding asymptotical capacity of steganographic systems is not attained by algorithms developed so far . in this paper , we describe a novel coding method based on @xmath0-linear codes that conforms to @xmath1-steganography , that is secret data is embedded into a cover message by distorting each symbol by one unit at most . this method solves some problems encountered by the most efficient methods known today , based on ternary hamming codes . finally , the performance of this new technique is compared with that of the mentioned methods and with the well - known theoretical upper bound . . And you have already written the first three sentences of the full article: _ steganography _ is a scientific discipline within the field known as _ data hiding _ , concerned with hiding information into a commonly used media , in such a way that no one apart from the sender and the intended recipient can detect the presence of embedded data . a comprehensive overview of the core principles and the mathematical methods that can be used for data hiding can be found in @xcite .. Please generate the next two sentences of the article

an interesting steganographic method is known as _ matrix encoding _ , introduced by crandall @xcite and analyzed by bierbrauer et al . matrix encoding requires the sender and the recipient to agree in advance on a parity check matrix @xmath2 , and the secret message is then extracted by the recipient as the syndrome ( with respect to @xmath2 ) of the received cover object .

Suppose that you have an abstract for a scientific paper: using a large sample ( @xmath0 11800 events ) of @xmath1 and @xmath2 decays collected by the cleo - c detector running at the @xmath3 , we measure the helicity basis form factors free from the assumptions of spectroscopic pole dominance and provide new , accurate measurements of the absolute branching fractions for @xmath4 and @xmath5 decays . we find branching fractions which are consistent with previous world averages . our measured helicity basis form factors are consistent with the spectroscopic pole dominance predictions for the three main helicity basis form factors describing @xmath6 decay . the ability to analyze @xmath2 allows us to make the first non - parametric measurements of the mass - suppressed form factor . our result is inconsistent with existing lattice qcd calculations . finally , we measure the form factor that controls non - resonant @xmath7-wave interference with the @xmath6 amplitude and search for evidence of possible additional non - resonant @xmath8- or @xmath9-wave interference with the @xmath10 . . And you have already written the first three sentences of the full article: we present new measurements of the @xmath4 and @xmath5 absolute branching fractions , their ratio , and measurements of the semileptonic form factors controlling these decays.@xmath11 modes as @xmath12 decays , and use the clebsch - gordan factor 1.5 to correct for @xmath13 decays , which we do not detect . ] exclusive charm semileptonic decays provide particularly simple tests of over decay dynamics since long distance effects only enter through the hadronic form factors @xcite . a wide variety of theoretical methods have been brought to bear on the calculation of these form factors including quark models @xcite , qcd sum rules @xcite , lattice qcd @xcite , analyticity @xcite , and others @xcite . using a technique developed by focus. Please generate the next two sentences of the article

@xcite , we present non - parametric measurements of the @xmath14 dependence of the helicity basis form factors that give an amplitude for the @xmath15 system to be in any one of its possible angular momentum states where @xmath14 is the invariant mass squared of the lepton pair in the decay . the ultimate goal of this study is to obtain a better understanding of the semileptonic decay intensity .

Suppose that you have an abstract for a scientific paper: we generalize kirchhoff s point vortex model of two - dimensional fluid motion to a rotor model which exhibits an inverse cascade by the formation of rotor clusters . a rotor is composed of two vortices with like - signed circulations glued together by an overdamped spring . the model is motivated by a treatment of the vorticity equation representing the vorticity field as a superposition of vortices with elliptic gaussian shapes of variable widths , augmented by a suitable forcing mechanism . the rotor model opens up the way to discuss the energy transport in the inverse cascade on the basis of dynamical systems theory . . And you have already written the first three sentences of the full article: the theoretical treatment of the longstanding problem of turbulent flows @xcite has to relate dynamical systems theory with non - equilibrium statistical physics @xcite . the central notion of physical turbulence theory is the concept of the energy cascade , highlighting the fact that turbulent flows are essentially transport processes of quantities like energy or enstrophy in scale . although well - established theories due to richardson , kolmogorov , onsager , heisenberg and others ( for reviews we refer the reader to @xcite ) can capture gross features of the cascade process in a phenomenological way , the dynamical aspects are by far less understood , and usually are investigated by direct numerical simulations of the navier - stokes equations .. Please generate the next two sentences of the article

an exception , in some sense , are inviscid fluid flows in two dimensions . based on the work of helmholtz @xcite , it was kirchhoff @xcite who pointed out that the partial differential equation can be reduced to a hamiltonian system for the locations of point vortices , provided one considers initial conditions where the vorticity is a superposition of delta - distributions ( we refer the reader to the works of aref @xcite as well as the monographs @xcite ) . due to onsager @xcite ( for a discussion we refer the reader to @xcite ) a statistical treatment of point vortex dynamics is possible for equilibrium situations because of the hamiltonian character of the dynamics , provided the ergodic hypothesis holds .

Suppose that you have an abstract for a scientific paper: we analyze a high - resolution spectrum of the a3 m star hd27411 . we compare abundances derived from atlas9 model atmospheres with those using the more computationally - intensive atlas12 code . we found very little differences in the abundances , suggesting that atlas9 can be used for moderate chemical peculiarity . our abundances agree well with the predictions of diffusion theory , though for some elements it was necessary to calculate line profiles in non - thermodynamic equilibrium to obtain agreement . we investigate the effective temperatures and luminosities of am / fm stars using synthetic strmgren indices derived from calculated spectra with the atmospheric abundances of hd27411 . we find that the effective temperatures of am / fm stars derived from strmgren photometry are reliable , but the luminosities are probably too low . caution is required when deriving the reddening of these stars owing to line blanketing effects . a comparison of the relative proportions of pulsating and non - pulsating am stars with @xmath0 scuti stars shows quite clearly that there is no significant decrease of helium in the driving zone , contrary to current models of diffusion . [ firstpage ] stars : chemically peculiar stars : individual : hd27411 stars : abundances . And you have already written the first three sentences of the full article: the `` metallic - lined '' or am stars are a - type stars which have strong absorption lines of some metals such as zn , sr , zr and ba and weaker lines of other metals such as ca and/or sc relative to their spectral type as determined by the strength of the hydrogen lines @xcite . the strong metallic lines are more typical of an f star rather than an a star . the work of @xcite established radiative diffusion in a strong magnetic field as the likely cause of the chemical peculiarities in ap stars .. Please generate the next two sentences of the article

when the magnetic field is absent , diffusion leads to the am / fm stars @xcite . the presence of magnetic fields in am stars has been investigated , but with negative results , ( e.g. @xcite ) .

Suppose that you have an abstract for a scientific paper: we study the spin resonance in superconducting state of iron - based materials within multiband models with two unequal gaps , @xmath0 and @xmath1 , on different fermi surface pockets . we show that due to the indirect nature of the gap entering the spin susceptibility at the nesting wave vector @xmath2 the total gap @xmath3 in the bare susceptibility is determined by the sum of gaps on two different fermi surface sheets connected by @xmath2 . for the fermi surface geometry characteristic to the most of iron pnictides and chalcogenides , the indirect gap is either @xmath4 or @xmath5 . in the @xmath6 state , spin excitations below @xmath3 are absent unless additional scattering mechanisms are assumed . the spin resonance appears in the @xmath7 superconducting state at frequency @xmath8 . comparison with available inelastic neutron scattering data confirms that what is seen is the true spin resonance and not a peak inherent to the @xmath6 state . . And you have already written the first three sentences of the full article: fe - based superconductors ( febs ) represent a non - cuprate class of high-@xmath9 systems with the unconventional superconducting state . the origin of the latter is still debated . in general , febs can be divided into the two subclasses , pnictides and chalcogenides @xcite , with the square lattice of iron as the basic element , though with orthorhombic distortions in lightly doped materials . iron is surrounded by as or p situated in the tetrahedral positions within the first subclass and by se , te , or s within the second subclass .. Please generate the next two sentences of the article

fermi surface ( fs ) is formed by fe @xmath10-orbitals and excluding the cases of extreme hole and electron dopings it consists of two hole sheets around the @xmath11 point and two electron sheets around the @xmath12 and @xmath13 points in the two - dimensional brillouin zone ( bz ) corresponding to one fe per unit cell ( the so - called 1-fe bz ) @xcite . in the 2-fe bz , electron pockets are centered at the @xmath14 point .

Suppose that you have an abstract for a scientific paper: we introduce a two - dimensional short - range correlated disorder that is the natural generalization of the well - known one - dimensional dual random dimer model [ phys . rev . lett * 65 * , 88 ( 1990 ) ] . we demonstrate that , as in one dimension , this model induces a localization - delocalization transition in the single - particle spectrum . moreover we show that the effect of such a disorder on a weakly - interacting boson gas is to enhance the condensate spatial homogeneity and delocalisation , and to increase the condensate fraction around an effective resonance of the two - dimensional dual dimers . this study proves that short - range correlations of a disordered potential can enhance the quantum coherence of a weakly - interacting many - body system . . And you have already written the first three sentences of the full article: the presence of impurities usually deeply modify the nature of the spectrum of a quantum system , and thus its coherence and transport properties . in the absence of interactions , if the impurity distribution is completely random , all states of the spectrum are exponentially localized in dimensions one ( 1d ) and two ( 2d ) , while a mobility edge exists in dimensions three ( 3d)@xcite . if the impurity positions are correlated , as for instance if it exists a minimum distance between the impurities @xcite , some delocalized states can appear in the spectrum . this was demonstrated in 1d in the context of the random dimer model ( rdm ) and of the dual random dimer model ( drdm ) @xcite . in 1d. Please generate the next two sentences of the article

, the effects of correlated disorder was studied in different physical contexts ( see for instance @xcite ) . in 2d , the effect of correlations is almost unexplored , except for the case of a speckle potential @xcite , and for the case of pseudo-2d random dimer lattices with separable dimensions @xcite .

Suppose that you have an abstract for a scientific paper: we study the predictability of emergent phenomena in complex systems . using nearest neighbor , one - dimensional cellular automata ( ca ) as an example , we show how to construct local coarse - grained descriptions of ca in all classes of wolfram s classification . the resulting coarse - grained ca that we construct are capable of emulating the large - scale behavior of the original systems without accounting for small - scale details . several ca that can be coarse - grained by this construction are known to be universal turing machines ; they can emulate any ca or other computing devices and are therefore undecidable . we thus show that because in practice one only seeks coarse - grained information , complex physical systems can be predictable and even decidable at some level of description . the renormalization group flows that we construct induce a hierarchy of ca rules . this hierarchy agrees well with apparent rule complexity and is therefore a good candidate for a complexity measure and a classification method . finally we argue that the large scale dynamics of ca can be very simple , at least when measured by the kolmogorov complexity of the large scale update rule , and moreover exhibits a novel scaling law . we show that because of this large - scale simplicity , the probability of finding a coarse - grained description of ca approaches unity as one goes to increasingly coarser scales . we interpret this large scale simplicity as a pattern formation mechanism in which large scale patterns are forced upon the system by the simplicity of the rules that govern the large scale dynamics . . And you have already written the first three sentences of the full article: the scope of the growing field of complexity science `` ( or complex systems '' ) includes a broad variety of problems belonging to different scientific areas . examples for complex systems `` can be found in physics , biology , computer science , ecology , economy , sociology and other fields . a recurring theme in most of what is classified as complex systems '' is that of _ emergence_. emergent properties are those which arise spontaneously from the collective dynamics of a large assemblage of interacting parts .. Please generate the next two sentences of the article

a basic question one asks in this context is how to derive and predict the emergent properties from the behavior of the individual parts . in other words , the central issue is how to extract large - scale , global properties from the underlying or microscopic degrees of freedom . in the physical sciences ,

Suppose that you have an abstract for a scientific paper: we present the results of an imaging observation campaign conducted with the subaru telescope adaptive optics system ( ircs+ao188 ) on 28 gravitationally lensed quasars and candidates ( 23 doubles , 1 quad , 1 possible triple and 3 candidates ) from the sdss quasar lens search . we develop a novel modelling technique that fits analytical and hybrid point spread functions ( psfs ) , while simultaneously measuring the relative astrometry , photometry , as well as the lens galaxy morphology . we account for systematics by simulating the observed systems using separately observed psf stars . the measured relative astrometry is comparable with that typically achieved with the hubble space telescope , even after marginalizing over the psf uncertainty . we model for the first time the quasar host galaxies in 5 systems , without a - priory knowledge of the psf , and show that their luminosities follow the known correlation with the mass of the supermassive black hole . for each system , we obtain mass models far more accurate than those previously published from low - resolution data , and we show that in our sample of lensing galaxies the observed light profile is more elliptical than the mass , for ellipticity @xmath0 . we also identify eight doubles for which the sources of external and internal shear are more reliably separated , and should therefore be prioritized in monitoring campaigns aimed at measuring time - delays in order to infer the hubble constant . [ firstpage ] adaptive optics gravitationally lensed quasars quasar host galaxies . And you have already written the first three sentences of the full article: the first gravitationally lensed quasar @xcite has been discovered more than 30 years ago , turning gravitational lensing from an obscure theoretical field into a mainstream observational one . more than 100 strongly lensed quasars have been discovered to date , and it has convincingly been demonstrated that these objects provide insights into various topics in astrophysics and cosmology , as well as being a unique tool for studying the dark universe . applications include the study of the quasar host galaxies at high redshift ( e.g. , * ? ? ?. Please generate the next two sentences of the article

* ) , dark matter substructures and luminous satellites ( e.g. , * ? ? ? * ; * ? ? ?

Suppose that you have an abstract for a scientific paper: the decay of a false vacuum of unbroken @xmath0@xmath1@xmath2 symmetry is an intriguing and testable mechanism to generate the initial conditions of the hot early universe . if @xmath0@xmath1@xmath2 is broken at the grand unification scale , the false vacuum phase yields hybrid inflation , ending in tachyonic preheating . the dynamics of the @xmath0@xmath1@xmath2 breaking higgs field and thermal processes produce an abundance of heavy neutrinos whose decays generate entropy , baryon asymmetry and gravitino dark matter . we study the phase transition for the full supersymmetric abelian higgs model . for the subsequent reheating process we give a detailed time - resolved description of all particle abundances . the competition of cosmic expansion and entropy production leads to an intermediate period of constant ` reheating ' temperature , during which baryon asymmetry and dark matter are produced . consistency of hybrid inflation , leptogenesis and gravitino dark matter implies relations between neutrino parameters and superparticle masses . in particular , for a gluino mass of @xmath3 , we find a lower bound on the gravitino mass of @xmath4 . desy 11 - 174 + march 2012 * spontaneous @xmath0@xmath1@xmath2 breaking as + the origin of the hot early universe * w. buchmller , v. domcke , k. schmitz + _ deutsches elektronen - synchrotron desy , 22607 hamburg , germany _ . . And you have already written the first three sentences of the full article: neutrino masses , baryogenesis , dark matter and the acoustic peaks in the power spectrum of the cosmic microwave background ( cmb ) radiation require an extension of the standard model of particle physics . the supersymmetric standard model with right - handed neutrinos and spontaneously broken @xmath0@xmath1@xmath2 , the difference of baryon and lepton number , provides a minimal framework which can account for all these phenomena @xcite . @xmath0@xmath1@xmath2 breaking at the grand unification ( gut ) scale leads to an elegant explanation of the small neutrino masses via the seesaw mechanism and explains baryogenesis via leptogenesis @xcite . the lightest supersymmetric particle is an excellent candidate for dark matter @xcite and the spontaneous breaking of @xmath0@xmath1@xmath2 requires an extended scalar sector , which automatically yields hybrid inflation @xcite , explaining the inhomogeneities of the cmb .. Please generate the next two sentences of the article

recently , we have suggested that the decay of a false vacuum of unbroken @xmath0@xmath1@xmath2 symmetry generates the initial conditions of the hot early universe : nonthermal and thermal processes produce an abundance of heavy neutrinos whose decays generate primordial entropy , baryon asymmetry via leptogenesis and gravitino dark matter from scatterings in the thermal bath @xcite . in this context , tachyonic preheating after hybrid inflation @xcite sets the stage for a matter dominated phase whose evolution is described by boltzmann equations , finally resulting in a radiation dominated phase . it is remarkable that the initial conditions of this radiation dominated phase are not free parameters but are determined by the parameters of a lagrangian , which in principle can be measured by particle physics experiments and astrophysical observations .

Suppose that you have an abstract for a scientific paper: many natural systems are organized as networks , in which the nodes interact in a time - dependent fashion . the object of our study is to relate connectivity to the temporal behavior of a network in which the nodes are ( real or complex ) logistic maps , coupled according to a connectivity scheme that obeys certain constrains , but also incorporates random aspects . we investigate in particular the relationship between the system architecture and possible dynamics . in the current paper we focus on establishing the framework , terminology and pertinent questions for low - dimensional networks . a subsequent paper will further address the relationship between hardwiring and dynamics in high - dimensional networks . + for networks of both complex and real node - maps , we define extensions of the julia and mandelbrot sets traditionally defined in the context of single map iterations . for three different model networks , we use a combination of analytical and numerical tools to illustrate how the system behavior ( measured via topological properties of the _ julia sets _ ) changes when perturbing the underlying adjacency graph . we differentiate between the effects on dynamics of different perturbations that directly modulate network connectivity : increasing / decreasing edge weights , and altering edge configuration by adding , deleting or moving edges . we discuss the implications of considering a rigorous extension of fatou - julia theory known to apply for iterations of single maps , to iterations of ensembles of maps coupled as nodes in a network . * real and complex behavior for networks of coupled logistic maps * + anca rdulescu@xmath0 , ariel pignatelli@xmath1 + @xmath2 department of mathematics , suny new paltz , ny 12561 @xmath1 department of mechanical engineering , suny new paltz , ny 12561 + . And you have already written the first three sentences of the full article: because many natural systems are organized as networks , in which the nodes ( be they cells , individuals , populations or web servers ) interact in a time - dependent fashion the study of networks has been an important focus in recent research . one of the particular points of interest has been the question of how the hardwired _ structure _ of a network ( its underlying graph ) affects its _ function _ , for example in the context of optimal information storage or transmission between nodes along time . it has been hypothesized that there are two key conditions for optimal function in such networks : a well - balanced adjacency matrix ( the underlying graph should appropriately combine robust features and random edges ) and well - balanced connection strengths , driving optimal dynamics in the system .. Please generate the next two sentences of the article

however , only recently has mathematics started to study rigorously ( through a combined graph theoretical and dynamic approach ) the effects of configuration patterns on the efficiency of network function , by applying graph theoretical measures of segregation ( clustering coefficient , motifs , modularity , rich clubs ) , integration ( path length , efficiency ) and influence ( node degree , centrality ) . various studies have been investigating the sensitivity of a system s temporal behavior to removing / adding nodes or edges at different places in the network structure , and have tried to relate these patterns to applications to natural networks .

Suppose that you have an abstract for a scientific paper: thermodynamic bulk measurements of binding reactions rely on the validity of the law of mass action and the assumption of a dilute solution . yet important biological systems such as allosteric ligand - receptor binding , macromolecular crowding , or misfolded molecules may not follow these assumptions and require a particular reaction model . here we introduce a fluctuation theorem for ligand binding and an experimental approach using single - molecule force - spectroscopy to determine binding energies , selectivity and allostery of nucleic acids and peptides in a model - independent fashion . a similar approach could be used for proteins . this work extends the use of fluctuation theorems beyond unimolecular folding reactions , bridging the thermodynamics of small systems and the basic laws of chemical equilibrium . binding energies are key quantities determining the fate of intermolecular reactions @xcite . bulk experimental approaches such as surface plasmon resonance , isothermal titration calorimetry and fluorescent ligand binding assays , allow the extraction of binding energies ( @xmath0 ) from measurements of the dissociation constant ( @xmath1 ) with accuracy @xmath21 kcal / mol through the expression : @xmath3~ , \label{eq : masact}\ ] ] where @xmath4 is the boltzmann constant , and @xmath5 the temperature @xcite . however , many ligands such as dna - binding proteins display different binding modes with varying affinities , or require the concerted action of several subunits , making quantitative measurements challenging @xcite . force techniques such as optical tweezers can be used to pull on individual ligand - dna complexes allowing detection of binding events one - at - a - time ( figure 1*a * , inset ) @xcite . however , force - induced ligand unbinding usually takes place in non - equilibrium conditions , and binding energies can not be directly inferred from the measured work values . the crooks fluctuation theorem and the jarzynski equality @xcite are tools.... And you have already written the first three sentences of the full article: all authors acknowledge funding from grants erc magreps 267 862 , fp7 grant infernos 308850 , icrea academia 2013 and fis2013 - 47796- p. all data used in this study are included in the main text and in the supplementary materials . j.c .- s . and a.a . equally contributed to this work .. Please generate the next two sentences of the article

[ sec : author ] * ecori binding to dna . * * ( a ) * unfolding / refolding force - distance curves of a dna hairpin in the absence ( magenta / black ) and presence ( blue / cyan ) of ecori protein .

Suppose that you have an abstract for a scientific paper: it has been ten years since the first report for a positive strangeness pentaquark - like baryon state . however the existence of the pentaquark state is still controversial . some contradictions between the experiments are unsolved . in this paper we review the experimental search for the pentaquark candidates @xmath0 , @xmath1 , @xmath2 , @xmath3 and @xmath4 in details . we review the experiments with positive results and compare the experiments with similar conditions but opposite results . . And you have already written the first three sentences of the full article: hadrons are the bound states of the strong interaction which is described by the quantum chromodynamics ( qcd ) in the framework of yang - mills gauge theory . one of the main goals of the hadron physics is to understand the composition of hadrons in terms of quarks and gluons . the quark model is proved successful in classifying the mesons and baryons as @xmath5 and @xmath6 composite systems .. Please generate the next two sentences of the article

almost all the well established mesons can be described as a quark - antiquark state except some mesons with exotic quantum numbers which are impossible for a @xmath5 system , but no experimental evidence is reported for exotic baryons which are inconsistent with the @xmath6 configuration until the beginning of this century . theoretically , the qcd does not forbid the existence of the hadrons with the other configurations , such as the glueballs , the hybrids and the multiquarks . in this review ,

Suppose that you have an abstract for a scientific paper: the need to produce accurate estimates of vertex degree in a large network , based on observation of a subnetwork , arises in a number of practical settings . we study a formalized version of this problem , wherein the goal is , given a randomly sampled subnetwork from a large parent network , to estimate the actual degree of the sampled nodes . depending on the sampling scheme , trivial method of moments estimators ( mmes ) can be used . however , the mme is not expected , in general , to use all relevant network information . in this study , we propose a handful of novel estimators derived from a risk - theoretic perspective , which make more sophisticated use of the information in the sampled network . theoretical assessment of the new estimators characterizes under what conditions they can offer improvement over the mme , while numerical comparisons show that when such improvement obtains , it can be substantial . illustration is provided on a human trafficking network . . And you have already written the first three sentences of the full article: frequently it is the case in the study of real - world complex networks that we observe essentially a sample from a larger network . there are many reasons why sampling in networks is often unavoidable and , in some cases , even desirable . sampling , for example , has long been a necessary part of studying internet topology @xcite .. Please generate the next two sentences of the article

similarly , its role has been long - recognized in the context of biological networks , e.g. , protein - protein interaction @xcite , gene regulation @xcite and metabolic networks @xcite . finally , in recent years , there has been intense interest in the use of sampling for monitoring online social media networks .

Suppose that you have an abstract for a scientific paper: determining the size of a maximum independent set of a graph @xmath0 , denoted by @xmath1 , is an np - hard problem . therefore many attempts are made to find upper and lower bounds , or exact values of @xmath2 for special classes of graphs . this paper is aimed toward studying this problem for the class of generalized petersen graphs . we find new upper and lower bounds and some exact values for @xmath3 . with a computer program we have obtained exact values for each @xmath4 . in @xcite it is conjectured that the size of the minimum vertex cover , @xmath5 , is less than or equal to @xmath6 , for all @xmath7 and @xmath8 with @xmath9 . we prove this conjecture for some cases . in particular , we show that if @xmath10 , the conjecture is valid . we checked the conjecture with our table for @xmath11 and it had no inconsistency . finally , we show that for every fixed @xmath8 , @xmath12 can be computed using an algorithm with running time @xmath13 . * keywords * : generalized petersen graphs , independent set , tree decomposition . And you have already written the first three sentences of the full article: in a graph @xmath14 , an independent set @xmath15 is a subset of the vertices of @xmath0 such that no two vertices in @xmath15 are adjacent . the independence number @xmath2 is the cardinality of a largest set of independent vertices and an independent set of size @xmath2 is called an @xmath16-set . the maximum independent set problem is to find an independent set with the largest number of vertices in a given graph .. Please generate the next two sentences of the article

it is well - known that this problem is np - hard @xcite . therefore , many attempts are made to find upper and lower bounds , or exact values of @xmath2 for special classes of graphs .

Suppose that you have an abstract for a scientific paper: we have investigated the tunneling properties of an electron double quantum well system where the lowest landau level of each quantum well is half filled . this system is expected to be a bose condensate of excitons . our four - terminal dc measurements reveal a nearly vanishing interlayer voltage and the existence of critical tunneling currents @xmath0 which depend on the strength of the condensate state . . And you have already written the first three sentences of the full article: macroscopic quantum systems such as superconductors and superfluids are the remarkable consequence of many of bosonic particles occupying the same lowest energy state , and thus forming a bose - einstein condensate ( bec ) . the design of closely spaced two dimensional electron systems ( 2des ) which can be contacted independently is the foundation to create a bec of excitons in semiconductors @xcite . exposed to a strong perpendicular magnetic field @xmath1 , the density of states of each of the 2des will condense into a discrete set of sub - bands , the landau levels . the total number of occupied states is then parameterized by the filling factor @xmath2 . if the electron densities @xmath3 are tuned to be identical in both layers , the filling factors will simultaneously be at @xmath4 at a particular @xmath1 . governed by coulomb interactions. Please generate the next two sentences of the article

, the bilayer system can then be viewed as a bose condensate of interlayer quasi - excitons by coupling an electron from layer 1 to a vacant state from layer 2 and vice versa . since these excitons have an infinite life time , their properties can be investigated via electrical transport experiments .

Suppose that you have an abstract for a scientific paper: accurate forecasting is important for cost - effective and efficient monitoring and control of the renewable energy based power generation . wind based power is one of the most difficult energy to predict accurately , due to the widely varying and unpredictable nature of wind energy . although autoregressive ( ar ) techniques have been widely used to create wind power models , they have shown limited accuracy in forecasting , as well as difficulty in determining the correct parameters for an optimized ar model . in this paper , constriction factor particle swarm optimization ( cf - pso ) is employed to optimally determine the parameters of an autoregressive ( ar ) model for accurate prediction of the wind power output behaviour . appropriate lag order of the proposed model is selected based on akaike information criterion . the performance of the proposed pso based ar model is compared with four well - established approaches ; forward - backward approach , geometric lattice approach , least - squares approach and yule - walker approach , that are widely used for error minimization of the ar model . to validate the proposed approach , real - life wind power data of _ capital wind farm _ was obtained from australian energy market operator . experimental evaluation based on a number of different datasets demonstrate that the performance of the ar model is significantly improved compared with benchmark methods . constriction factor particle swarm optimization ( cf - pso ) , ar model , wind power prediction . And you have already written the first three sentences of the full article: in recent years , renewable energy has gained much popularity and attention because of it s potential in economic and environmental advantages . some of the benefits include- high stainability , low carbon emission , reduction of environmental impact , saving fuel cost and so on . other advantages include economical benefits to remote communities and supporting the microgrids during the operation in islanded mode . although renewable energy , e.g. , wind and solar , offers huge benefits @xcite , their practical use is limited due to their intermittent nature which makes it very challenging to ensure a steady power supply in the grid @xcite . because of the variable nature of the renewable energy based power generation sources , transmission and distribution system operators need advanced monitoring and control .. Please generate the next two sentences of the article

wind power generation relies on wind speed which varies depending on location and time . for economic and stable operation of the wind power plant , accurate forecasting of wind power is critical .

Suppose that you have an abstract for a scientific paper: we present a novel , highly efficient algorithm to parallelize @xmath0direct summation method for @xmath1-body problems with individual timesteps on distributed - memory parallel machines such as beowulf clusters . previously known algorithms , in which all processors have complete copies of the @xmath1-body system , has the serious problem that the communication - computation ratio increases as we increase the number of processors , since the communication cost is independent of the number of processors . in the new algorithm , @xmath2 processors are organized as a @xmath3 two - dimensional array . each processor has @xmath4 particles , but the data are distributed in such a way that complete system is presented if we look at any row or column consisting of @xmath5 processors . in this algorithm , the communication cost scales as @xmath6 , while the calculation cost scales as @xmath7 . thus , we can use a much larger number of processors without losing efficiency compared to what was practical with previously known algorithms . _ pacs : 02.60.cb;95.10.ce ; 98.10.+z _ celestial mechanics , stellar dynamics;methods : numerical # 1@xmath8 # 1@xmath9 # 1*[#1 piet ] * # 1*[#1 jun ] * = cmbx10 scaled 2 . And you have already written the first three sentences of the full article: in this paper we present a novel algorithm to parallelize the direct summation method for astrophysical @xmath1-body problems , either with and without the individual timestep algorithm . the proposed algorithm works also with the ahmad - cohen neighbor scheme @xcite , or with grape special - purpose computers for @xmath1-body problems @xcite . our algorithm is designed to offer better scaling of the communication - computation ratio on distributed - memory multicomputers such as beowulf pc clusters @xcite compared to traditional algorithms .. Please generate the next two sentences of the article

this paper will be organized as follows . in section 2 we describe the traditional algorithms to parallelize direct summation method on distributed - memory parallel computers , and the scaling of communication time and computational time as functions of the number of particles @xmath1 and number of processor @xmath2 . it will be shown that for previously known algorithms the calculation time scales as @xmath10 , while communication time is @xmath11 .

Suppose that you have an abstract for a scientific paper: we show the asymptotic long - time equivalence of a generic power law waiting time distribution to the mittag - leffler waiting time distribution , characteristic for a time fractional continuous time random walk . this asymptotic equivalence is effected by a combination of rescaling " time and respeeding " the relevant renewal process followed by a passage to a limit for which we need a suitable relation between the parameters of rescaling and respeeding . as far as we know such procedure has been first applied in the 1960s by gnedenko and kovalenko in their theory of thinning " a renewal process . turning our attention to spatially one - dimensional continuous time random walks with a generic power law jump distribution , rescaling " space can be interpreted as a second kind of respeeding " which then , again under a proper relation between the relevant parameters leads in the limit to the space - time fractional diffusion equation . finally , we treat the time fractional drift " process as a properly scaled limit of the counting number of a mittag - leffler renewal process . = 10000 -1.5truecm -0.5truecm = cmr10 = cmr10 at 10 truept -0.75 truecm invited lecture by r. gorenflo at the 373 we - heraeus - seminar on anomalous transport : experimental results and theoretical challenges , physikzentrum bad - honnef ( germany ) , 12 - 16 july 2006 . it will appear in the book _ anomalous transport : foundations and applications _ edited by r. klages , g. radons and i.m sokolov , as chapter 4 , pp . 93 - 127 , wiley - vch , weinheim , germany ( 2008 ) . @xmath0 -2.0truecm = 10000 = 2000 # 11 l = cmbx12 scaled1 . And you have already written the first three sentences of the full article: the purpose of this paper is to outline the fundamental role the mittag - leffler function in renewal processes that are relevant in the theories of anomalous diffusion . as a matter of fact the interest in this function in statistical physics and probability theory has recently increased as is shown by the large number of papers published since 1990 of which a brief ( incomplete ) bibliography includes . in this paper we develop a theory for long - time behaviour of a renewal process with a generic power law waiting distribution of order @xmath1 , @xmath2 ( thereby for easy readability dispensing with decoration by a slowly varying function ) . to bring the distant future into near sight we change the unit of time from @xmath3 to @xmath4 , @xmath5 . for the random waiting times. Please generate the next two sentences of the article

@xmath6 this means replacing @xmath6 by @xmath7 . then , having very many events in a moderate span of time we compensate this compression by respeeding the whole process , actually slowing it down so that again we have a moderate number of events in a moderate span of time .

Suppose that you have an abstract for a scientific paper: in this paper , we simulate the prompt emission light curves of gamma - ray bursts ( grbs ) within the framework of the internal - collision - induced magnetic reconnection and turbulence ( icmart ) model . this model applies to grbs with a moderately high magnetization parameter @xmath0 in the emission region . we show that this model can produce highly variable light curves with both fast and slow components . the rapid variability is caused by many locally doppler - boosted mini - emitters due to turbulent magnetic reconnection in a moderately high @xmath0 flow . the runaway growth and subsequent depletion of these mini - emitters as a function of time define a broad slow component for each icmart event . a grb light curve is usually composed of multiple icmart events that are fundamentally driven by the erratic grb central engine activity . allowing variations of the model parameters , one is able to reproduce a variety of light curves and the power density spectra as observed . . And you have already written the first three sentences of the full article: a gamma - ray burst ( grb ) event comprises two phases , prompt emission and afterglow . the prompt @xmath1-ray emission is usually highly variable , with many pulses overlapping within a short duration ( fishman & meegan 1995 ) . the power density spectra ( pdss ) of the light curves are typically a power law with a possible turnover at high frequencies ( beloborodov et al . 2000 ) .. Please generate the next two sentences of the article

the light curves may be decomposed as the superposition of an underlying slow component and a more rapid fast component ( gao et al . the fast component tends to be more significant in high energies , and becomes less significant at lower frequencies ( vetere et al .

Suppose that you have an abstract for a scientific paper: in this paper , we show that markov s principle is not derivable in dependent type theory with natural numbers and one universe . one tentative way to prove this would be to remark that markov s principle does not hold in a sheaf model of type theory over cantor space , since markov s principle does not hold for the generic point of this model . it is however not clear how to interpret the universe in a sheaf model @xcite . instead we design an extension of type theory , which intuitively extends type theory by the addition of a generic point of cantor space . we then show the consistency of this extension by a normalization argument . markov s principle does not hold in this extension , and it follows that it can not be proved in type theory . . And you have already written the first three sentences of the full article: markov s principle has a special status in constructive mathematics . one way to formulate this principle is that if it is impossible that a given algorithm does not terminate , then it does terminate . it is equivalent to the fact that if a set of natural number and its complement are both computably enumerable , then this set is decidable .. Please generate the next two sentences of the article

this form is often used in recursivity theory . this principle was first formulated by markov , who called it `` leningrad s principle '' , and founded a branch of constructive mathematics around this principle @xcite .

Suppose that you have an abstract for a scientific paper: we calculate analytically and numerically the dyer - roeder distance in perfect fluid quintessence models and give an accurate fit to the numerical solutions for all the values of the density parameter and the quintessence equation of state . then we apply our solutions to the estimation of @xmath0 from multiple image time delays and find that the inclusion of quintessence modifies sensibly the likelihood distribution of @xmath0 , generally reducing the best estimate with respect to a pure cosmological constant . marginalizing over the other parameters ( @xmath1 and the quintessence equation of state ) , we obtain @xmath2 km / sec / mpc for an empty beam and @xmath3 km / sec / mpc for a filled beam . we also discuss the future prospects for distinguishing quintessence from a cosmological constant with time delays . epsf.tex -.5 in . And you have already written the first three sentences of the full article: quintessence ( caldwell et al . 1998 ) or dark energy is a new component of the cosmic medium that has been introduced in order to explain the dimming of distant snia ( riess et al . 1998 ; perlmutter et al . 1999 ) through an accelerated expansion while at the same time saving the inflationary prediction of a flat universe . the recent measures of the cmb at high resolution ( lange et al .. Please generate the next two sentences of the article

2000 , de bernardis et al . 2000 , balbi et al .

Suppose that you have an abstract for a scientific paper: we explore the role of soft gluon exchange in heavy quarkonium production at large transverse momentum . we find uncanceled infrared poles at nnlo that are not matched by conventional nrqcd matrix elements . we show , however , that gauge invariance and factorization require that conventional nrqcd production operators be modified to include nonabelian phases or wilson lines . with appropriately modified operators , factorization is restored at nnlo . we also argue that , in the absence of special cancellations , infrared poles at yet higher orders may require the inclusion of additional nonlocal operators , not present in the nrqcd expansion in relative veloctiy . yitp - sb-05 - 01 + * fragmentation , factorization and infrared poles + * in heavy quarkonium production gouranga c. nayak@xmath0 , jian - wei qiu@xmath1 and george sterman@xmath0 _ @xmath0c.n . yang institute for theoretical physics , stony brook university , suny + stony brook , new york 11794 - 3840 , u.s.a . _ _ @xmath1department of physics and astronomy , iowa state university + ames , ia 50011 , u.s.a . _ pacs numbers : 12.38.bx , 12.39.st , 13.87.fh,14.40gx . And you have already written the first three sentences of the full article: the production of heavy quarkonium offers a unique perspective into the process of hadronization , because the creation of the relevant valence partons , the heavy quarks , is essentially perturbative . quarkonium production and decay have been the subject of a vast theoretical literature and of intensive experimental study , in which the effective field theory nonrelativistic qcd ( nrqcd ) @xcite has played a guiding role . nrqcd offers a systematic formalism to separate dynamics at the perturbative mass scale of the heavy quarks from nonperturbative dynamics , through an expansion in relative velocity within the pair forming the bound state . in nrqcd. Please generate the next two sentences of the article

, the description of the relevant nonperturbative dynamics is reduced to the determination of a limited number of qcd matrix elements , accessible from experiment and , in principle , lattice computation . a characteristic feature of the application of nrqcd to production processes is the indispensible role of color octet matrix elements , which describe the nonperturbative transition of quark pairs in adjoint representation into quarkonia through soft gluon emission .

Suppose that you have an abstract for a scientific paper: the fundamental paradox of the incompatibility of the observed large - scale uniformity of the universe with the fact that the age of the universe is finite is overcome by the introduction of an initial a period of superluminal expansion of space , called cosmic inflation . inflation can also produce the small deviations from uniformity needed for the formation of structures in the universe such as galaxies . this is achieved by the conjunction of inflation with the quantum vacuum , through the so - called particle production process . this mechanism is explained and linked with hawking radiation of black holes . the nature of the particles involved is discussed and the case of using massive vector boson fields instead of scalar fields is presented , with emphasis on its distinct observational signatures . finally , a particular implementation of these ideas is included , which can link the formation of galaxies , the standard model vector bosons and the observed galactic magnetic fields . inflation , particle production , primordial density perturbation , cmb radiation , structure formation . And you have already written the first three sentences of the full article: there are a few facts about the universe we live in that we have now become certain of . one such fact is that our universe is expanding . in 1929 edwin hubble discovered that distant galaxies appear to be receding from us with velocity proportional to their distance ( see fig .. Please generate the next two sentences of the article

[ hubble ] ) : @xmath0 where @xmath1 is the famous hubble constant , whose value is @xcite . this observation marks the discovery that we live in an expanding universe .

Suppose that you have an abstract for a scientific paper: a small number of double - lobed radio galaxies are found with an additional pair of extended low surface brightness ` wings ' of emission giving them a distinctive ` x'-shaped appearance . one popular explanation for the unusual morphologies posits that the central supermassive black hole ( smbh)/accretion disk system underwent a recent realignment ; in a merger scenario , the active lobes mark the post - merger axis of the resultant system ( e.g. , merritt & ekers 2002 ) . however , this and other interpretations are not well tested on the few ( about one dozen ) known examples . in part to remedy this deficiency , a large sample of winged and x - shaped radio sources is being compiled for a systematic study . an initial sample of 100 new candidates is described as well as some of the follow - up work being pursued to test the different scenarios . . And you have already written the first three sentences of the full article: to compile the sample , image fields from the vla - first survey ( becker et al . 1995 ) containing components bright and extended enough to judge the source morphologies were inspected by - eye . this gave an initial 100 candidates with extended winged emission ( fig . 1 ; cheung 2006 ) .. Please generate the next two sentences of the article

compared to previously known examples ( e.g. , lal & rao 2006 ) , the new candidates are systematically fainter ( @xmath010@xmath1 ) and more distant ( @xmath2@xmath30.3 ) . new optical spectroscopic observations are identifying many of the fainter , more distant optical hosts .

Suppose that you have an abstract for a scientific paper: the worldsheet sigma - model of the superstring in @xmath0 has a one - parameter family of flat connections parametrized by the spectral parameter . the corresponding wilson line is not brst invariant for an open contour , because the brst transformation leads to boundary terms . these boundary terms define a cohomological complex associated to the endpoint of the contour . we study the cohomology of this complex for wilson lines in some infinite - dimensional representations . we find that for these representations the cohomology is nontrivial at the ghost number 2 . this implies that it is possible to define a brst invariant open wilson line . the central point in the construction is the existence of massless vertex operators transforming exactly covariantly under the action of the global symmetry group . in flat space massless vertices transform covariantly up to adding brst exact terms , but in ads it is possible to define vertices so that they transform exactly covariantly . calt-68 2722 * @xmath1 + @xmath1 + symmetries of massless vertex operators in @xmath0 * + + + . And you have already written the first three sentences of the full article: nonlocal conserved charges play the central role in quantum integrability @xcite . for the superstring in @xmath0 their existence was proven in the classical sigma - model in @xcite using the green - schwarz - metsaev - tseytlin formalism , and in @xcite using the pure spinor formalism . the existence of the nonlocal conserved charges at the quantum level was proven in @xcite .. Please generate the next two sentences of the article

the most important feature of the string worldsheet @xmath2-model ( besides the conformal invariance ) is the existence of the brst structure . the physically meaningful constructions should respect the action of the brst operator @xmath3 .

Suppose that you have an abstract for a scientific paper: nonreciprocal devices that permit wave transmission in only one direction are indispensible in many fields of science including , e.g. , electronics , optics , acoustics , and thermodynamics . manipulating phonons using such nonreciprocal devices may have a range of applications such as phonon diodes , transistors , switches , etc . one way of achieving nonreciprocal phononic devices is to use materials with strong nonlinear response to phonons . however , it is not easy to obtain the required strong mechanical nonlinearity , especially for few - phonon situations . here , we present a general mechanism to amplify nonlinearity using @xmath0-symmetric structures , and show that an on - chip micro - scale phonon diode can be fabricated using a @xmath0-symmetric mechanical system , in which a lossy mechanical - resonator with very weak mechanical nonlinearity is coupled to a mechanical resonator with mechanical gain but no mechanical nonlinearity . when this coupled system transits from the @xmath0-symmetric regime to the broken-@xmath0-symmetric regime , the mechanical nonlinearity is transferred from the lossy resonator to the one with gain , and the effective nonlinearity of the system is significantly enhanced . this enhanced mechanical nonlinearity is almost lossless because of the gain - loss balance induced by the @xmath0-symmetric structure . such an enhanced lossless mechanical nonlinearity is then used to control the direction of phonon propagation , and can greatly decrease ( by over three orders of magnitude ) the threshold of the input - field intensity necessary to observe the unidirectional phonon transport . we propose an experimentally realizable lossless low - threshold phonon diode of this type . our study opens up new perspectives for constructing on - chip few - phonon devices and hybrid phonon - photon components . . And you have already written the first three sentences of the full article: owing to recent progress in nanotechnology and materials science , nano- and micro - mechanics @xcite have emerged as subjects of great interest due to their potential use in demonstrating macroscopic quantum phenomena , and possible applications in precision measurements , detecting gravitational waves , building filters , signal amplification , as well as switches and logic gates . in particular , on - chip single- or few - phonon devices are ideal candidates for hybrid quantum information processing , due to the ability of phonons to interact and rapidly switch between optical fields and microwave fields @xcite . fabrication of high - frequency mechanical resonators @xcite , demonstration of coherent phonon coupling between nanomechanical resonators @xcite , ground - state cooling @xcite , optomechanics ( in microtoroids @xcite , microspheres @xcite , microdisks @xcite , microring @xcite , photonic crystals @xcite , doubly- or singly - clamped cantilevers @xcite , and membranes @xcite ) have opened new directions @xcite and provided new tools to control and manipulate phonons in on - chip devices . one possible obstacle to further develop this field is the ability to control the flow of phonons , allowing transport in one direction but not the opposite direction @xcite , i.e. , nonreciprocal phonon transport .. Please generate the next two sentences of the article

there have been several attempts to fabricate nonreciprocal devices for phonons @xcite , but these are almost exclusively based on asymmetric linear structures which indeed can not break lorentz reciprocity : a static linear structure can not break reciprocity @xcite . these proposed linear structures do obey the reflection - transmission reciprocity and thus can not be considered as phonon diodes " .