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Suppose that you have an abstract for a scientific paper: since the experimental realisation of the integer quantised hall effect in a two dimensional electron system subject to strong perpendicular magnetic fields in 1980 , a central question has been the interrelation between the conductance quantisation and the topological properties of the system . it is conjectured that if the electron system is described by a bloch hamiltonian , then the system is insulating in the bulk of the sample throughout the quantised hall plateau due to magnetic field induced energy gap . meanwhile , the system is conducting at the edges resembling a 2 + 1 dimensional topological insulator without the time - reversal symmetry . however , the validity of this conjecture remains unclear for finite size , non - periodically bounded real hall bar devices . here we show experimentally that the close relationship proposed between the quantised hall effect and the topological bulk insulator is prone to break for specific magnetic field intervals within the plateau evidenced by our magneto - transport measurements performed on gaas / algaas high purity hall bars with two inner contacts embedded to bulk . our data presents a similar behaviour also for fractional states , in particular for 2/3 , 3/5 and 4/3 . the mutual relation between the integer quantised hall effect @xcite ( iqhe ) and topology is a reoccurring theme . @xcite salient features of the iqhe are the precise hall conductance measured as integer multiples of the conductance quanta @xmath0 ( @xmath1 is the elementary charge and @xmath2 is the planck constant ) accompanied by zero longitudinal resistance at certain magnetic field intervals . the robustness of the iqhe against material systems points to a universal origin , which is claimed to be the topology of the system @xcite and relies on a key argument : the bulk of the two dimensional electron system ( 2des ) is incompressible . @xcite for the iqhe , the incompressible state is a direct consequence of the quantising magnetic field @xmath3 localising.... And you have already written the first three sentences of the full article: in this supplementary material section we will first provide the details of our experimental setup and then discuss the validity of some crucial assumptions of the well known theories of the iqhe . namely , first we will briefly discuss the assumptions on different boundary conditions and topological aspects of the quantized hall samples within the single - particle ( sp ) theories . the main discussion is on the mapping between the momentum space representation of the edge states to real space representation .. Please generate the next two sentences of the article

this discussion clarifies the importance of boundary conditions , where the normalisation condition is the only physical restriction . here , instead of a detailed mathematical description we will make use of some schematic presentations which are common in the qhe discussions . however , to lift the confusion between different theories we used distinguishing colours to discriminate single - particle and screening theory concepts , e.g. incompressibility , edge states , etc .

Suppose that you have an abstract for a scientific paper: the analysis of the early star formation history ( sfh ) of nearby galaxies , obtained from their resolved stellar populations is relevant as a test for cosmological models . however , the early time resolution of observationally derived sfhs is limited by several factors . thus , direct comparison of observationally derived sfhs with those derived from theoretical models of galaxy formation is potentially biased . here we investigate and quantify this effect . for this purpose , we analyze the duration of the early star formation activity in a sample of four local group dwarf galaxies and test whether they are consistent with being true fossils of the pre - reionization era ; i.e. , if the quenching of their star formation occurred before cosmic reionization by uv photons was completed . two classical dsph ( cetus and tucana ) and two dtrans ( lgs-3 and phoenix ) isolated galaxies with total stellar masses between @xmath0 to @xmath1 m@xmath2 have been studied . accounting for time resolution effects , the sfhs peak as much as 1.25 gyr earlier than the optimal solutions . thus , this effect is important for a proper comparison of model and observed sfhs . it is also shown that none of the analyzed galaxies can be considered a true - fossil of the pre - reionization era , although it is possible that the _ outer regions _ of cetus and tucana are consistent with quenching by reionization . . And you have already written the first three sentences of the full article: dwarf galaxies are at the focus of a major cosmological problem affecting the @xmath3cdm scenario : the number of dark matter subhalos around milky way - type galaxies predicted by @xmath3cdm simulations is much larger than the number of observed satellite dwarf galaxies @xcite . most proposals to overcome this problem stem from the idea that the smallest halos would have formed very few stars or failed to form stars at all , and that gas would have been removed in an early epoch . in this way , the lowest mass sub - halos would be either completely dark , and thus undetectable , or extremely faint . two main mechanisms are usually invoked as responsible of the smallest sub - halos failing to have an extended star formation history ( sfh ) : heating from cosmic ultraviolet ( uv ) background radiation arising from the earliest star formation in the universe @xcite and internal sn feedback following the first star formation episodes in the host dwarf galaxy .. Please generate the next two sentences of the article

the cosmic uv background raises the entropy of the intergalactic medium around the epoch of reionization , preventing baryons from falling into the smallest sub - halos and it can also heat and evaporate the interstellar medium of larger sub - halos which have managed some star formation . the former would never form stars while the latter would presently show only a very old stellar population .

Suppose that you have an abstract for a scientific paper: we analyze the behavior of an ensemble of inertial particles in a one - dimensional smooth gaussian velocity field , in the limit of large inertia , but considering a finite correlation time for the random field . the amplitude of the concentration fluctuations is characterized by slow decay at large inertia and a much larger correlation length than that of the random field . the fluctuation structure in velocity space is very different from predictions from short - time correlated random velocity fields , with only few particle pairs crossing at sufficiently small relative velocity to produce correlations . concentration fluctuations are associated with depletion of the relative velocity variance of colliding particles . v *o * = cmr10 at 24truept = cmbx10 at 15truept . And you have already written the first three sentences of the full article: starting from the work of deutsch @xcite , it has been known for some time now , that inertial particles in a random velocity field undergo clustering phenomena . these behaviors are observed in numerical simulation of turbulence as well ( see e.g @xcite and references therein ) and are thought to give an important contribution to coalescence phenomena , e.g. in the process of rain formation @xcite . both in the case of random fields and of real turbulence , spatial inhomogeneity of the statistics , though contributing to particle segregation @xcite , does not appear to be an essential factor .. Please generate the next two sentences of the article

random velocity fields with various statistical properties , have been used to model inertial particles in turbulent flows , both in the presence of gravity @xcite and in its absence @xcite . simplified models disregarding in part or in total the spatial structure of the velocity field have been introduced as well ( see e.g. @xcite ) , to cope with the difficulty of the analytical treatment of the multi - particle statistics . in the simplest instance , an inertial particle in a turbulent flow is characterized by the relaxation time of its velocity relative to the fluid : the stokes time @xmath0 , where @xmath1 is the particle radius , @xmath2 is the ratio of the particle to fluid density ( assumed large ) and @xmath3 is the kinematic viscosity of the fluid @xcite . experimental data @xcite and numerical simulations @xcite both indicate that clustering is stronger for particles with @xmath4 of the order of the kolmogorov time scale .

Suppose that you have an abstract for a scientific paper: texture specific fermion mass matrices have played an important role in understanding several features of fermion masses and mixings . in the present work , we have given an overview of all possible cases of fritzsch - like as well as non fritzsch - like texture 6 and 5 zero fermion mass matrices . further , for the case of texture 4 zero fritzsch - like quark mass matrices , the issue of the hierarchy of the elements of the mass matrices and the role of their phases have been discussed . furthermore , the case of texture 4 zero fritzsch - like lepton mass matrices has also been discussed with an emphasis on the hierarchy of neutrino masses for both majorana and dirac neutrinos . . And you have already written the first three sentences of the full article: understanding fermion masses and mixings is one of the outstanding problem of present day particle physics . the idea of quark mixing phenomena was initiated by cabibbo in 1963 @xcite , subsequently generalized to two generations by glashow , illiopoulos , maiani @xcite and finally to three generations by kobayashi and maskawa @xcite . this has been tested to a great accuracy and is well accommodated by the standard model ( sm ) .. Please generate the next two sentences of the article

recently , flavor mixing has also been observed in the case of neutrinos implying the existence of non zero , non degenerate neutrino masses necessitating the need to look beyond sm . also , one has to go beyond the sm in order to understand the pattern of quark masses and mixing parameters as in the sm the quark mass matrices are completely arbitrary . in view of the relationship of fermion mixing phenomena with that of fermion mass matrices , the understanding of the above mentioned issues of flavor physics essentially implies formulating fermion mass matrices . while on the one hand , grand unified theories ( guts ) have provided vital clues for understanding the relationship of fermion mass matrices between quarks and leptons , on the other hand , horizontal symmetries @xcite have given clues for the relationship between different generation of fermions .

Suppose that you have an abstract for a scientific paper: within the standard model , we investigate the semi - leptonic weak decays of @xmath0 . the various form factors of @xmath0 transiting to a single charmed meson ( @xmath1 ) are studied in the framework of the qcd sum rules . these form factors fully determine the rates of the weak semi - leptonic decays of @xmath0 and provide valuable information about the non - perturbative qcd effects . our results indicate that the decay rate of the semi - leptonic weak decay mode @xmath2 is at order of @xmath3 . . And you have already written the first three sentences of the full article: although strong and electromagnetic decays of @xmath0 have been extensively studied for several decades , both experimental and theoretical investigations of weak decays of @xmath0 are much behind . due to smallness of the strength of weak interaction , the weak decays of the @xmath0 are rare processes . sanchis - lonzano suggested to search for these rare decays whose sum of branching ratios were estimated to be at the order of @xmath4 @xcite .. Please generate the next two sentences of the article

such processes hardly drew much attention because the database was far from reaching such accuracy . thus , for a long time , few further researches on this topic were done .

Suppose that you have an abstract for a scientific paper: we analyze two regions of the quiet sun ( @xmath0 mm@xmath1 ) observed at high spatial resolution ( @xmath2100 km ) in polarized light by the imax spectropolarimeter onboard the sunrise balloon . we identify 497 small - scale ( @xmath3400 km ) magnetic loops , appearing at an effective rate of 0.25 loop h@xmath4 arcsec@xmath5 ; further , we argue that this number and rate are underestimated by @xmath330% . however , we find that these small dipoles do not appear uniformly on the solar surface : their spatial distribution is rather filamentary and clumpy , creating _ dead calm _ areas , characterized by a very low magnetic signal and a lack of organized loop - like structures at the detection level of our instruments , that can not be explained as just statistical fluctuations of a poisson spatial process . we argue that this is an intrinsic characteristic of the mechanism that generates the magnetic fields in the very quiet sun . the spatio - temporal coherences and the clumpy structure of the phenomenon suggest a recurrent , intermittent mechanism for the generation of magnetic fields in the quietest areas of the sun . . And you have already written the first three sentences of the full article: during the last few years , our understanding of the structure , organization and evolution of magnetic fields in the very quiet sun ( the regions outside active regions and the network ) has become increasingly clear . magnetic fields in the quietest areas of the sun are relatively weak and organized at small spatial scales , which yields weak polarization signals that are difficult to observe . until very recently , the general picture of the structure of its magnetism was rather rough : a `` turbulent '' disorganized field @xcite . it is now clear that even in very quiet areas , magnetic fields may organize as coherent loops at granular and subgranular scales ( @xmath21000 km ; * ? ? ?. Please generate the next two sentences of the article

* ) , that these small loops are dynamic @xcite , that they pervade the quiet solar surface and may even connect with upper atmospheric layers @xcite . yet , this picture is still incomplete .

Suppose that you have an abstract for a scientific paper: the magnetic fields affect collapse of molecular cloud cores . here , we consider a collapsing core with an axial magnetic field and investigate its effect on infall of matter and formation of accretion disk . for this purpose , the equations of motion of ions and neutral infalling particles are numerically solved to obtain the streamlines of trajectories . the results show that in non - steady state of ionization and ion - neutral coupling , which is not unexpected in the case of infall , the radius of accretion disk will be larger as a consequence of axial magnetic field . . And you have already written the first three sentences of the full article: a lot of observational information is now known about the structure of dense cores as progenitors of stars within the molecular clouds ( e.g. , evans 2010 ) . theoretically , we expect that most of these cores will collapse into protostars , but the details of evolutions are less evident . clearly , the evolution heavily depends upon the effects of local density , pressure , rotation , magnetic fields , the presence or absence of nearby stars and protostars , and upon the other physical phenomena . the most commonly used picture of low - mass star formation is inside - out collapse ( shu 1977 ) in which it begins at the center of a singular isothermal sphere and an expanding wave of infalling matter propagates outward with the speed of sound . up to now. Please generate the next two sentences of the article

, different models for core collapse and formation of protostars have been presented , in each the effects of some physical phenomena investigated ( e.g. , mckee and ostriker 2007 ) . the velocity maps of molecular cloud cores , which are built by using the velocity measurements along the line of sight , show a small velocity gradient across each core . measuring this global velocity gradient , with assumption that core has a uniform rotation and

Suppose that you have an abstract for a scientific paper: the peaceman - rachford splitting method is very efficient for minimizing sum of two functions each depends on its variable , and the constraint is a linear equality . however , its convergence was not guaranteed without extra requirements . very recently , he _ et al . _ ( siam j. optim . 24 : 1011 - 1040 , 2014 ) proved the convergence of a strictly contractive peaceman - rachford splitting method by employing a suitable underdetermined relaxation factor . in this paper , we further extend the so - called strictly contractive peaceman - rachford splitting method by using two different relaxation factors , and to make the method more flexible , we introduce semi - proximal terms to the subproblems . we characterize the relation of these two factors , and show that one factor is always underdetermined while the other one is allowed to be larger than 1 . such a flexible conditions makes it possible to cover the glowinski s admm whith larger stepsize . we show that the proposed modified strictly contractive peaceman - rachford splitting method is convergent and also prove @xmath0 convergence rate in ergodic and nonergodic sense , respectively . the numerical tests on an extensive collection of problems demonstrate the efficiency of the proposed method . * key words * : semi - proximal , strictly contractive , peaceman - rachford splitting method , convex minimization , convergence rate . . And you have already written the first three sentences of the full article: we consider the convex minimization problem with linear constraints and a separable objective function @xmath1 where @xmath2 and @xmath3 are continuous closed convex ( could be nonsmooth ) functions ; @xmath4 and @xmath5 are given matrices ; @xmath6 is a given vector ; @xmath7 and @xmath8 are nonempty closed convex subsets of @xmath9 and @xmath10 , respectively . throughout , the solution set of ( [ cp ] ) is assumed to be nonempty ; and @xmath7 and @xmath8 are assumed to be simple in the sense that it is easy to compute the projections under the euclidean norm onto them ( e.g. , positive orthant , spheroidal or box areas ) . let @xmath11 be the augmented lagrangian function for that defined by @xmath12 in which @xmath13 is the multiplier associated to the linear constraint and @xmath14 is a penalty parameter .. Please generate the next two sentences of the article

based on the classic douglas - rachford operator splitting method @xcite , the alternating direction method of multipliers was proposed by gabay and mercier @xcite , glowinski and marrocco @xcite in the mid-1970s , which generates the iterative sequence via the following recursion : [ alx ] x^k+1=_x_(x , y^k,^k ) , + [ aly]y^k+1=_y_(x^k+1,y,^k ) , + [ all]^k+1=^k-(ax^k+1+by^k+1-b ) . based on another classic operator splitting method , i.e. , peaceman - rachford operator splitting method @xcite , one can derive the following method for : [ alxp ] x^k+1=_x_(x , y^k,^k ) , + [ allb]^k+=^k-(ax^k+1+by^k+1-b ) , + [ alyp]y^k+1=_y_(x^k+1,y,^k+ ) , + [ allp]^k+1=^k+-(ax^k+1+by^k+1-b ) .

Suppose that you have an abstract for a scientific paper: coherent control of femtosecond two - photon absorption in the intermediate - field regime is analyzed in detail in the powerful frequency domain using an extended 4@xmath0-order perturbative description . the corresponding absorption is coherently induced by the weak - field non - resonant two - photon transitions as well as by four - photon transitions involving three absorbed photons and one emitted photons . the interferences between these two groups of transitions lead to a difference between the intermediate - field and weak - field absorption dynamics . the corresponding interference nature ( constructive or destructive ) strongly depends on the detuning direction of the pulse spectrum from half the two - photon transition frequency . the model system of the study is atomic sodium , for which both experimental and theoretical results are obtained . the detailed understanding obtained here serves as a basis for coherent control with rationally - shaped femtosecond pulses in a regime of sizable absorption yields . . And you have already written the first three sentences of the full article: femtosecond pulses offer unique ways to coherently control photo - induced quantum dynamics of matter @xcite . the corresponding key characteristic is their coherence over a broad spectrum . multiphoton absorption processes in atoms and molecules , which are of fundamental scientific importance as well as applicative importance to the fields of nonlinear spectroscopy and microscopy , are among the processes that have been controlled most effectively by shaped femtosecond pulses @xcite .. Please generate the next two sentences of the article

the control principle is the coherent manipulation of interferences among the manifold of initial - to - final state - to - state multiphoton pathways that are induced by the pulse . constructive interferences lead to absorption enhancement ( i.e. , increased transition probability ) , while destructive interferences lead to absorption attenuation ( i.e. , decreased transition probability ) . the interference manipulation is implemented by shaping the femtosecond pulse @xcite , i.e. , manipulating the spectral phase , amplitude , and/or polarization of its different frequency components .

Suppose that you have an abstract for a scientific paper: in this paper we provide a characterization of intrinsic lipschitz graphs in the sub - riemannian heisenberg groups in terms of their distributional gradients . moreover , we prove the equivalence of different notions of continuous weak solutions to the equation @xmath0_{t}=w$ ] , where @xmath1 is a bounded measurable function depending on @xmath2 . . And you have already written the first three sentences of the full article: in the last years it has been largely developed the study of intrinsic submanifolds inside the heisenberg groups @xmath3 or more general carnot groups , endowed with their carnot - carathodory metric structure , also named sub - riemannian . by an intrinsic regular ( or intrinsic lipschitz ) hypersurfaces we mean a submanifold which has , in the intrinsic geometry of @xmath3 , the same role like a @xmath4 ( or lipschitz ) regular graph has in the euclidean geometry . intrinsic regular graphs had several applications within the theory of rectifiable sets and minimal surfaces in cc geometry , in theoretical computer science , geometry of banach spaces and mathematical models in neurosciences , see @xcite , @xcite and the references therein . we postpone complete definitions of @xmath3 to section [ s : hnrecalls ] .. Please generate the next two sentences of the article

we only remind that the heisenberg group @xmath5 is the simplest example of carnot group , endowed with a left - invariant metric @xmath6 ( equivalent to its carnot - carathodory metric ) , not equivalent to the euclidean metric . @xmath3 is a ( connected , simply connected and stratified ) lie group and has a sufficiently rich compatible underlying structure , due to the existence of intrinsic families of left translations and dilations and depending on the horizontal vector fields @xmath7 .

Suppose that you have an abstract for a scientific paper: _ the objective of this paper is twofold : ( i ) to survey existing results of generalized polynomials on time scales , covering definitions and properties for both delta and nabla derivatives ; ( ii ) to extend previous results by using the more general notion of diamond - alpha derivative on time scales . we introduce a new notion of combined - polynomial series on a time scale , as a convex linear combination of delta and nabla generalized series . main results are formulated for homogenous time scales . as an example , we compute diamond - alpha derivatives on time scales for delta and nabla exponential functions . _ * keywords : * time scales , diamond-@xmath0 derivatives , generalized polynomials , generalized series . * 2000 mathematics subject classification : * 40c99 , 39a13 , 40a30 . . And you have already written the first three sentences of the full article: polynomial series are of great importance in control theory . both continuous and discrete polynomial series are useful in approximating state and/or control variables , in modal reduction , optimal control , and system identification , providing effective and efficient computational methods @xcite . from recent years , the theory of control for discrete and continuous time is being unified and extended by using the formalism of time scales : see @xcite and references therein. Please generate the next two sentences of the article

. looking to the literature on time scales , one understands that such unification and extension is not unique . two main directions are being followed : one uses @xmath1-derivatives while the other chooses @xmath2-derivatives instead . in this paper

Suppose that you have an abstract for a scientific paper: the period changes of six eclipsing binaries have been studied with focus on the light - time effect . with the least squares method we also calculated parameters of such effect and properties of the unresolved body in these systems . with these results we discussed probability of presence of such bodies in the systems with respect to possible confirmation by another method . in two systems we also suggested a hypothesis of fourth body or magnetic activity for explanation of the `` second - order variability '' after subtraction of the light - time effect of the third body . . And you have already written the first three sentences of the full article: eclipsing binary systems provide a good opportunity for studying the presence of an unresolved third body by observing their minima times because of the light - time effect ( hereafter lite ) . it was explained by irwin and its necessary criteria have been mentioned by frieboes - conde & hertzeg and also by mayer . presence of the third body in the system is possible only if the times of minima behave in agreement with a theoretical lite curve , the resultant mass function has reasonable value and corresponding variations in radial velocities are measured . in the last decade also. Please generate the next two sentences of the article

a confirmation by astrometry seems to be plausible . in each case we have calculated new light elements of the eclipsing pair and also the parameters of the predicted third body orbit .

Suppose that you have an abstract for a scientific paper: the recent discoveries of circumbinary planets by @xmath0 raise questions for contemporary planet formation models . understanding how these planets form requires characterizing their formation environment , the circumbinary protoplanetary disc , and how the disc and binary interact and change as a result . the central binary excites resonances in the surrounding protoplanetary disc that drive evolution in both the binary orbital elements and in the disc . to probe how these interactions impact binary eccentricity and disk structure evolution , n - body smooth particle hydrodynamics ( sph ) simulations of gaseous protoplanetary discs surrounding binaries based on kepler 38 were run for @xmath1 binary periods for several initial binary eccentricities . we find that nearly circular binaries weakly couple to the disc via a parametric instability and excite disc eccentricity growth . eccentric binaries strongly couple to the disc causing eccentricity growth for both the disc and binary . discs around sufficiently eccentric binaries that strongly couple to the disc develop an @xmath2 spiral wave launched from the 1:3 eccentric outer lindblad resonance ( eolr ) that corresponds to an alignment of gas particle longitude of periastrons . all systems display binary semimajor axis decay due to dissipation from the viscous disc . = 1 [ firstpage ] binaries : general hydrodynamics protoplanetary discs . And you have already written the first three sentences of the full article: observations by @xmath3 of binary systems have so far yielded 11 transiting circumbinary planets . until recently , all discovered circumbinary planets have resided near to or outside the dynamical stability limit characterized by @xcite . this finding has prompted many to study how planets form in such systems and why they seem biased towards lying at the brink of dynamical instability @xcite .. Please generate the next two sentences of the article

simulations and theoretical arguments by @xcite and @xcite rule out in situ formation in the inner edge of the disc near where several circumbinary planets have been observed . currently , one of the most successful models in explaining the circumbinary planet population is planetary migration . in this model , a planet , having formed farther out in the disc , migrates inward through viscous interactions with a gaseous disc , potentially undergoing planet - planet scattering , until it reaches near its observed location .

Suppose that you have an abstract for a scientific paper: the availability of bose - einstein condensates as mesoscopic or macroscopic quantum objects has aroused new interest in the possiblity of making and detecting coherent superpositions involving many atoms . in this article we show that it may be possible to generate such a superposition state in a reasonably short time using feshbach resonances to tune the inter - atomic interactions in a double - well condensate . we also consider the important problem of distinguishing whether a coherent superposition or a statistical mixture is generated by a given experimental procedure . we find that unambiguously distinguishing even a perfect ` noon ' state from a statistical mixture using standard detection methods will present experimental difficulties . . And you have already written the first three sentences of the full article: the idea of a macroscopic state demonstrating quantum mechanical behaviour was introduced by schrdinger in 1935 @xcite . his famous thought experiment considered how a macroscopic entity ( in this case a domestic cat ) could evolve into a superposition of two distinct physical states ( alive and dead ) when entangled with a microscopic system that obeyed the laws of quantum mechanics . this possibility of a macroscopic system being simultaneously in two distinct physical states was initially considered to be a flaw in quantum mechanical theory @xcite .. Please generate the next two sentences of the article

however , experiments have shown the predictions of quantum mechanics to be correct as superpositions of macroscopically distinct physical states have been produced in a variety of systems . these are often referred to as ` schrdinger cat states ' .

Suppose that you have an abstract for a scientific paper: modifications of photoionization arising from resonant electron - electron correlations between neighbouring atoms in an atomic sample are studied . the sample contains atomic species @xmath0 and @xmath1 , with the ionization potential of @xmath0 being smaller than the energy of a dipole - allowed transition in @xmath1 . the atoms are subject to an external radiation field which is near - resonant with the dipole transition in @xmath1 . photoionization of an atom @xmath0 may thus proceed via a two - step mechanism : photoexcitation in the subsystem of species @xmath1 , followed by interatomic coulombic decay . as a basic atomic configuration , we investigate resonant photoionization in a three - atomic system @xmath0-@xmath1-@xmath1 , consisting of an atom @xmath0 and two neighbouring atoms @xmath1 . it is found that , under suitable conditions , the influence of the neighbouring atoms can strongly affect the photoionization process , including its total probabilty , time development and photoelectron spectra . in particular , by comparing our results with those for photoionization of an isolated atom @xmath0 and a two - atomic system @xmath0-@xmath1 , respectively , we reveal the characteristic impact exerted by the third atom . . And you have already written the first three sentences of the full article: photoionization of atoms and molecules is one of the most fundamental quantum processes . it played a key role in the early days of quantum mechanics and has ever since been paving the way towards an improved understanding of the structure and dynamics of matter on a microscopic scale . today , kinematically complete photoionization experiments allow for accurate tests of the most sophisticated ab - initio calculations . besides , photoionization studies in a new frequency domain are currently becoming feasible by the availability of novel xuv and x - ray radiation sources @xcite , giving rise to corresponding theoretical developments ( see , e.g. , @xcite ) .. Please generate the next two sentences of the article

various photoionization mechanisms rely crucially on electron - electron correlations . prominent examples are single - photon double ionization as well as resonant photoionization .

Suppose that you have an abstract for a scientific paper: we find new non - abelian flux tube solutions in a model of @xmath0 scalar fields in the fundamental representation of @xmath1 with @xmath2 ( the `` extended non - abelian higgs model '' ) , and study their main properties . among the solutions there are spinning strings as well as superconducting ones . the solutions exist only in a non trivial domain of the parameter space defined by the ratio between the @xmath3 and @xmath4 coupling constants , the scalar self - interaction coupling constants , the magnetic fluxes ( abelian as well as non - abelian ) and the `` twist parameter '' which is a non - trivial relative phase of the higgs fields . . And you have already written the first three sentences of the full article: non - abelian stringlike solutions have a long history which starts already in 1973 with the nielsen - olesen seminal paper @xcite . several general discussions were published @xcite and explicit solutions ( numerical of course ) were obtained @xcite for an @xmath3 gauge theory with higgs fields in the adjoint representation which completely break the symmetry . however , the major part of the activity in the field of cosmic strings @xcite was concentrated on their abelian counterparts .. Please generate the next two sentences of the article

one reason for this is that these non - abelian string solutions have their flux directed in a fixed direction in the corresponding algebra so they are essentially abelian . in recent years , new kinds of non - abelian strings were discovered during attempts to understand the phenomenon of confinement in qcd @xcite , and their properties were studied extensively @xcite .

Suppose that you have an abstract for a scientific paper: it is known that any subharmonic quadrature domain in two dimensions satisfies a natural inner ball condition , in other words there is a specific upper bound on the curvature of the boundary . this result directly applies to free boundaries appearing in obstacle type problems and in hele - shaw flow . in the present paper we make partial progress on the corresponding question in higher dimensions . specifically , we prove the equivalence between several different ways to formulate the inner ball condition , and we compute the brouwer degree for a geometrically important mapping related to the schwarz potential of the boundary . the latter gives in particular a new proof in the two dimensional case . . And you have already written the first three sentences of the full article: in the present paper we study the curvature of a free boundary which comes up in some obstacle type problems , more specifically laplacian growth ( hele - shaw flow moving boundary problem ) , quadrature domains and partial balayage . the final aim of the investigations is to show that the free boundary in question satisfies a certain inner ball condition ( a specific upper bound on the curvature ) . this goal has previously been achieved in the case of two dimensions ( see @xcite and @xcite ; compare also @xcite ) . here. Please generate the next two sentences of the article

we shall give some partial results ( but no complete solution ) in higher dimensions , and in passing also obtain a new proof for the two dimensional case . the geometric property we aim at proving can most easily be stated in terms of quadrature domains for subharmonic functions @xcite .

Suppose that you have an abstract for a scientific paper: an infinite family of axially symmetric thin disks of finite radius is presented . the family of disks is obtained by means of a method developed by hunter and contains , as its first member , the kalnajs disk . the surface densities of the disks present a maximum at the center of the disk and then decrease smoothly to zero at the edge , in such a way that the mass distribution of the higher members of the family is more concentrated at the center . the first member of the family have a circular velocity proportional to the radius , representing thus a uniformly rotating disk . on the other hand , the circular velocities of the other members of the family increases from a value of zero at the center of the disks until a maximum and then decreases smoothly until a finite value at the edge of the disks , in such a way that for the higher members of the family the maximum value of the circular velocity is attained nearest the center of the disks . stellar dynamics galaxies : kinematics and dynamics . . And you have already written the first three sentences of the full article: a fact usually assumed in astrophysics is that the main part of the mass of a typical spiral galaxy is concentrated in a thin disk ( @xcite ) . accordingly , the obtention of the gravitational potential generated by an idealized thin disk is a problem of great astrophysical relevance and so , through the years , different approaches has been used to obtain such kind of thin disk models . wyse and mayall ( @xcite ) studied thin disks by superposing an infinite family of elementary disks of different radii .. Please generate the next two sentences of the article

brandt ( @xcite ) and brandt and belton ( @xcite ) constructed flat galaxy disks by the flattening of a distribution of matter whose surface of equal density were similar spheroids . a simple potential - density pair for a thin disk model was introduced by kuzmin ( @xcite ) and then rederived by toomre ( @xcite ) as the first member of a generalized family of models .

Suppose that you have an abstract for a scientific paper: we address a visibility problem posed by solomon & weiss @xcite . more precisely , in any dimension @xmath0 , we construct a forest @xmath1 with finite density satisfying the following condition : if @xmath2 denotes the radius common to all the trees in @xmath1 , then the visibility @xmath3 therein satisfies the estimate @xmath4 for any @xmath5 , no matter where we stand and what direction we look in . the proof involves fourier analysis and sharp estimates of exponential sums . . And you have already written the first three sentences of the full article: in @xcite , c. bishop sets the following problem : _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ `` suppose we stand in a forest with tree trunks of radius @xmath6 and no two trees centered closer than unit distance apart . can the trees be arranged so that we can never see further than some distance @xmath7 , no matter where we stand and what direction we look in ? what is the size of @xmath8 in terms of @xmath9 ? '' _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ this is an example of a visibility problem , a topic which has attracted substantial interest over the past decades see @xcite for a.... Please generate the next two sentences of the article

allen @xcite extended this result to the case when the disk has a non integer radius and kruskal @xcite dealt with the situation where the trees are centred at non zero points of any lattice .

Suppose that you have an abstract for a scientific paper: the strangeness - changing ( @xmath0 ) weak baryon - baryon interaction is studied through the nonmesonic weak decay of double-@xmath1 hypernuclei . besides the usual nucleon - induced decay @xmath2 we discuss novel hyperon - induced decay modes @xmath3 and @xmath4 . these reactions provide unique access to the exotic @xmath5k and @xmath6k vertices which place new constraints on chiral pertubation theory ( @xmath7pt ) in the weak su(3 ) sector . within a meson - exchange framework , we use the pseudoscalar @xmath8 octet for the long - range part while parametrizing the short - range part through the vector mesons @xmath9 . realistic baryon - baryon forces for the @xmath10 and @xmath11 sectors account for the strong interaction in the initial and final states . for @xmath12he the new hyperon - induced decay modes account for up to 4% of the total nonmesonic decay rate . predictions are made for all possible nonmesonic decay modes . . And you have already written the first three sentences of the full article: the production and weak decay properties of strangeness - rich systems is of fundamental importance for our understanding of relativistic heavy - ion collisions and certain astrophysical phenomena , such as neutron stars . the simplest systems with strangeness , hypernuclei with one or two bound @xmath1 s , have been used to study both the strong and the weak baryon - baryon ( bb ) interaction in the su(3 ) sector . until now , hypernuclear weak decay represents the only source of information on the @xmath13 four fermion interaction where , in contrast to the weak @xmath14 nn case , both the weak parity - conserving ( pc ) and parity - violating ( pv ) amplitudes can be studied . in the absence of exact solutions to low - energy qcd , effective field - theory techniques based on chiral expansions have been fairly successful in the description of hadronic observables in the ( non - strange ) su(2 ) sector .. Please generate the next two sentences of the article

the stability of the chiral expansion is less clear for the su(3 ) sector , due to the significant amount of su(3 ) symmetry breaking . a well - known failure of su(3 ) chiral perturbation theory has been the prediction@xcite of the four pc @xmath15-wave amplitudes in the weak nonleptonic decays of octet baryons , @xmath16 , with @xmath17 , @xmath18 or @xmath19 . since large cancellations among tree - level amplitudes are held responsible for the problem with the weak @xmath15-wave octet amplitudes , it is imperative to assess whether this situation is universal within su(3 ) @xmath7pt or limited to a few exceptional cases . however , other weak octet baryon - baryon - meson ( bbm ) vertices can only be accessed through reactions that allow for the virtual exchange of mesons , such as the reactions @xmath2 and @xmath20 . the process @xmath2 has been extensively studied in an approach where the long - range part of this interaction is based on the exchange of the su(3 ) pseudoscalar meson octet ( @xmath21 , @xmath22 , and @xmath23 ) .

Suppose that you have an abstract for a scientific paper: the paper is devoted to the complete classification of all real lie algebras of contact vector fields on the first jet space of one - dimensional submanifolds in the plane . this completes sophus lie s classification of all possible lie algebras of contact symmetries for ordinary differential equations . as a main tool we use the abstract theory of filtered and graded lie algebras . we also describe all differential and integral invariants of new lie algebras found in the paper and discuss the infinite - dimensional case . . And you have already written the first three sentences of the full article: the problem of describing all finite - dimensional lie algebras of vector fields is a starting point for the symmetry analysis of ordinary differential equations , because , having solved this problem , one finds all possible algebras of contact symmetries for ordinary differential equations . over the complex numbers this classification was done at the end of the last century by sophus lie @xcite . he showed that , with three exceptions , all lie algebras of contact vector fields , viewed up to equivalence , are lifts of lie algebras of vector fields on the plane .. Please generate the next two sentences of the article

the largest algebra of the three exceptions ( so - called _ irreducible algebras of contact vector fields _ ) is the algebra of contact symmetries of the equation @xmath0 and is isomorphic to @xmath1 , while the other two are its subalgebras of dimension 6 and 7 . in this paper we show that the problem of describing algebras of vector fields can be formulated in a natural way in terms of filtered and graded lie algebras .

Suppose that you have an abstract for a scientific paper: as cell proliferation is limited due to the loss of telomere repeats in dna of normal somatic cells during division , telomere attrition can possibly play an important role in determining the maximum life span of organisms as well as contribute to the process of biological ageing . with computer simulations of cell culture development in organisms , which consist of tissues of normal somatic cells with finite growth , we otain an increase of life span and life expectancy for longer telomeric dna in the zygote . by additionally considering a two - mutation model for carcinogenesis and indefinite proliferation by the activation of telomerase , we demonstrate that the risk of dying due to cancer can outweigh the positive effect of longer telomeres on the longevity . * does telomere elongation lead to a longer lifespan if cancer is considered ? * michael masa@xmath0 , stanisaw cebrat@xmath1 and dietrich stauffer@xmath0 @xmath0 institute for theoretical physics , cologne university , d-50923 kln , euroland @xmath1 institute of genetics and microbiology , university of wrocaw , + ul . przybyszewskiego 63/77 , pl-54148 wrocaw , poland _ keywords _ : biological ageing ; computer simulations ; telomeres ; telomerase ; cancer . And you have already written the first three sentences of the full article: telomeres are tandem repeated noncoding sequences of nucleotides at both ends of the dna in eukaryotic chromosomes stabilizing the chromosome ends and preventing them from end - to - end fusion or degradation @xcite . polymerase can not completely replicate the 3 end of linear dna , so telomeres are shortened at each dna replication @xcite . this end replication problem leads to a finite replicative capacity for normal somatic cells @xcite .. Please generate the next two sentences of the article

they can only divide up to a certain threshold , the hayflick limit @xcite . the enzyme telomerase , repressed in most normal somatic cells , synthesizes and elongates telomere repeat sequences at the end of dna strands so that certain cells like germline cells are immortal and indefinite in growth @xcite .

Suppose that you have an abstract for a scientific paper: physical security of power networks under power injection attacks that alter generation and loads is studied . the system operator employs phasor measurement units ( pmus ) for detecting such attacks , while attackers devise attacks that are _ unobservable _ by such pmu networks . it is shown that , given the pmu locations , the solution to finding the sparsest unobservable attacks has a simple form with probability one , namely , @xmath0 , where @xmath1 is defined as the vulnerable vertex connectivity of an augmented graph . the constructive proof allows one to find the entire set of the sparsest unobservable attacks in polynomial time . furthermore , a notion of the potential impact of unobservable attacks is introduced . with optimized pmu deployment , the sparsest unobservable attacks and their potential impact as functions of the number of pmus are evaluated numerically for the ieee 30 , 57 , 118 and 300-bus systems and the polish 2383 , 2737 and 3012-bus systems . it is observed that , as more pmus are added , the maximum potential impact among all the sparsest unobservable attacks drops quickly until it reaches the minimum sparsity . . And you have already written the first three sentences of the full article: modern power networks are increasingly dependent on information technology in order to achieve higher efficiency , flexibility and adaptability @xcite . the development of more advanced sensing , communications and control capabilities for power grids enables better situational awareness and smarter control . however , security issues also arise as more complex information systems become prominent targets of cyber - physical attacks : not only can there be data attacks on measurements that disrupt situation awareness @xcite , but also control signals of power grid components including generation and loads can be hijacked , leading to immediate physical misbehavior of power systems @xcite . furthermore , in addition to hacking control messages , a powerful attacker can also implement physical attacks by directly intruding upon power grid components .. Please generate the next two sentences of the article

therefore , to achieve reliable and secure operation of a smart power grid , it is essential for the system operator to minimize ( if not eliminate ) the feasibility and impact of physical attacks . there are many closely related techniques that can help achieve secure power systems .

Suppose that you have an abstract for a scientific paper: we report the discovery of excess 4.5 and 8@xmath0 m emission from three quiescent black hole low - mass x - ray binaries , a 0620@xmath100 , gs 2023 + 338 , and xte j1118 + 480 , and the lack of similar excess emission from cen x-4 . the mid - infrared emission from gs 2023 + 338 probably originates in the accretion disk . however , the excess emission from a 0620@xmath100 and xte j1118 + 480 is brighter and peaks at longer wavelengths , and most likely originates from circumbinary dust that is heated by the light of the secondary star . for these two sources , we find that the inner edges of the dust distributions lie near 1.7 times the binary separations , which are the minimum radie at which circumbinary disks would be stable against tidal disruption . the excesses are weak at 24 @xmath0 m , which implies that the dust does not extend beyond about 3 times the binary separations . the total masses of circumbinary material are between @xmath2 and @xmath3 g. the material could be the remains of fall - back disks produced in supernovae , or material from the companions injected into circumbinary orbits during mass transfer . . And you have already written the first three sentences of the full article: one of the main limiting factors in determining the masses of the compact objects in low - mass x - ray binaries is uncertainty in the fraction of the infrared light that is produced by the companion star ( e.g. , hynes , robinson , & bitner 2005 ) . when lmxbs are accreting at low rates , the optical and infrared light from these systems is dominated by the companion stars , so their mass functions can be measured to high accuracy based on the doppler motion of the companion ( e.g. , * ? ? ? the inclination then must be constrained by modeling the modulations in the optical and infrared light curves that are produced by the varying aspect of the distorted , roche - lobe - filling companion . generally ,. Please generate the next two sentences of the article

the contribution of the accretion disk to the optical and near - infrared emission is uncertain , and varying the fraction of the light that is assumed to be produced by the accretion disk can lead to differences of a factor of 2 in the derived mass of a compact object ( e.g. , gelino , harrison , & orosz 2001 ) . fortunately , the broad - band spectrum of a multi - temperature accretion disk is significantly flatter than that of a stellar photosphere , so mid - infrared observations could constrain the relative contributions of the two components .

Suppose that you have an abstract for a scientific paper: the @xmath0 symmetric potential @xmath1 $ ] has a completely real spectrum for @xmath2 , and begins to develop complex eigenvalues for @xmath3 . at the symmetry - breaking threshold @xmath4 some of the eigenvectors become degenerate , giving rise to a jordan - block structure for each degenerate eigenvector . in general this is expected to result in a secular growth in the amplitude of the wave . however , it has been shown in a recent paper by longhi , by numerical simulation and by the use of perturbation theory , that for a broad initial wave packet this growth is suppressed , and instead a saturation leading to a constant maximum amplitude is observed . we revisit this problem by explicitly constructing the bloch wave - functions and the associated jordan functions and using the method of stationary states to find the dependence on the longitudinal distance @xmath5 for a variety of different initial wave packets . this allows us to show in detail how the saturation of the linear growth arises from the close connection between the contributions of the jordan functions and those of the neighbouring bloch waves . . And you have already written the first three sentences of the full article: the study of quantum mechanical hamiltonians that are @xmath0-symmetric but not hermitian@xcite-@xcite has recently found an unexpected application in classical optics@xcite-@xcite , due to the fact that in the paraxial approximation the equation of propagation of an electromagnetic wave in a medium is formally identical to the schrdinger equation , but with different interpretations for the symbols appearing therein . the equation of propagation takes the form [ opteq ] i=-(+v(x ) ) , where @xmath6 represents the envelope function of the amplitude of the electric field , @xmath5 is a scaled propagation distance , and @xmath7 is the optical potential , proportional to the variation in the refractive index of the material through which the wave is passing . a complex @xmath8 corresponds to a complex refractive index , whose imaginary part represents either loss or gain . in principle the loss and gain regions can be carefully configured so that @xmath8 is @xmath0 symmetric , that is @xmath9 .. Please generate the next two sentences of the article

propagation through such a medium exhibits many new and interesting properties , such as nonreciprocal diffraction @xcite and birefringence @xcite . one of the main features of complex optical lattices is the non - conservation of the total power . in the @xmath0-symmetric case

Suppose that you have an abstract for a scientific paper: the phenix experiment at rhic has extended its scope to cover spin physics using polarized proton beams . the major goals of the spin physics at rhic are elucidation of the spin structure of the nucleon and precision tests of the symmetries . sensitivities of the spin physics measurements with the phenix detector system are reviewed . . And you have already written the first three sentences of the full article: the relativistic heavy ion collider ( rhic ) is under construction at brookhaven national laboratory . in addition to its primary purpose , the search for quark - gluon plasma , a proposal to explore spin physics at rhic @xcite has been approved . the major goals of the spin physics program at rhic are : * elucidation of the spin structure of the nucleon , and * precision tests of symmetries .. Please generate the next two sentences of the article

rhic offers a unique opportunity for those studies because of its capability of accelerating polarized proton beams up to @xmath0= 500 gev at the luminosity of 2@xmath110@xmath2@xmath3sec@xmath4 or more with large polarizations of @xmath570% . obviously we will reach the high - energy frontier for polarized proton - proton collisions at rhic .

Suppose that you have an abstract for a scientific paper: we establish some statistical properties of the _ hyperbolic times _ for a class of nonuniformly expanding dynamical systems . the maps arise as factors of area preserving maps of the unit square via a geometric baker s map type construction , exhibit intermittent dynamics , and have unbounded derivatives . the geometric approach captures various examples from the literature over the last thirty years . the statistics of these maps are controlled by the order of tangency that a certain `` cut function '' makes with the boundary of the square . using a large deviations result of melbourne and nicol we obtain sharp estimates on the distribution of first hyperbolic times . as shown by alves , viana and others , knowledge of the tail of the distribution of first hyperbolic times leads to estimates on the rate of decay of correlations and derivation of a clt . for our family of maps , we compare the estimates on correlation decay rate and clt derived via hyperbolic times with those derived by a direct young tower construction . the latter estimates are known to be sharp . let @xmath0 be a dynamical system which is expanding on average , but not necessarily uniformly with every time - step . amongst the important questions to ask about @xmath1 are : is there an invariant srb - probability measure ? how quickly do correlations between observables decay under iteration by @xmath1 ? does a central limit theorem hold ? are these properties stable to perturbations of @xmath1 ? when @xmath1 is _ uniformly expanding _ the answers to these questions are well understood ( see eg @xcite ) , but the situation for non - uniformly expanding @xmath1 is more delicate . difficulties arise from the fact that orbits of @xmath1 may experience periods of local contraction as well as expansion ( for example , quadratic maps @xcite ) , rapidly varying derivatives near singularities leading to unbounded distortion ( eg @xcite ) , or indifferent fixed points @xcite . the theory of _ hyperbolic times.... And you have already written the first three sentences of the full article: the generalized baker s construction @xcite defines a large class of invertible , lebesgue - measure - preserving maps of the unit square @xmath34\times[0,1]$ ] . specifically , a two - dimensional map @xmath35 on @xmath36 is determined by a measurable _ cut function _ @xmath37 on @xmath38 $ ] satisfying @xmath39 .. Please generate the next two sentences of the article

the graph @xmath40 partitions the square @xmath36 into upper and lower pieces and the line @xmath41 , where @xmath42 , partitions the square into a ` left half ' @xmath43 \times [ 0,1]$ ] and a ` right half ' @xmath44 \times [ 0,1]$ ] . the _ generalized baker s transformation _ ( gbt ) @xmath35 maps the left half into the lower piece and the right half into the upper piece in such a way that : * vertical lines in the left ( right ) half are mapped affinely into vertical ` half lines ' under ( over ) the graph of the cut function @xmath37 . * @xmath35 preserves two - dimensional lebesgue measure . * the factor action @xmath1 of @xmath35 restricted to vertical lines is ( conjugate to ) a piecewise monotone increasing , lebesgue - measure - preserving interval map on @xmath38 $ ] with two monotonicity pieces @xmath43 $ ] and @xmath44 $ ] .

Suppose that you have an abstract for a scientific paper: properties of local polyakov loops for su(2 ) and su(3 ) lattice gauge theory at finite temperature are analyzed . we show that spatial clusters can be identified where the local polyakov loops have values close to the same center element . for a suitable definition of these clusters the deconfinement transition can be characterized by the onset of percolation in one of the center sectors . the analysis is repeated for different resolution scales of the lattice and we argue that the center clusters have a continuum limit . center clusters in the yang - mills vacuum christof gattringer and alexander schmidt institut fr physik , universitt graz , + universittsplatz 5 , 8010 graz , austria . And you have already written the first three sentences of the full article: understanding the mechanisms that drive the transition to the deconfined regime is one of the great open problems of qcd . in particular with the expected new results from the experiments at the rhic , lhc and gsi facilities also the theoretical side is challenged to contribute to our understanding of confinement and the transition to the deconfined phase . since phase transitions are non - perturbative phenomena , the applied methods must be non - perturbative approaches .. Please generate the next two sentences of the article

a particularly powerful technique is the lattice formulation of qcd , where numerical simulations have become reliable quantitative tools of analysis . an interesting idea , which is partly rooted in the lattice formulation , is the svetitsky - jaffe conjecture @xcite which links the deconfinement transition of an su(@xmath0 ) gauge theory in @xmath1 dimensions to the magnetic transition of a @xmath2-dimensional spin system which is invariant under the center group @xmath3 . the spins of the system are related @xcite to the local polyakov loops , which are static quark sources in the underlying gauge theory .

Suppose that you have an abstract for a scientific paper: we have studied the superfluid density and the specific heat of the @xmath0 model on lattices @xmath1 with @xmath2 ( i.e. on lattices representing a film geometry ) using the cluster monte carlo method . in the @xmath3-direction we applied staggered boundary conditions so that the order parameter on the top and bottom layers is zero , whereas periodic boundary conditions were applied in the @xmath4-directions . we find that the system exhibits a kosterlitz - thouless phase transition at the @xmath3-dependent temperature @xmath5 below the critical temperature @xmath6 of the bulk system . however , right at the critical temperature the ratio of the areal superfluid density to the critical temperature is @xmath3-dependent in the range of film thicknesses considered here . we do not find satisfactory finite - size scaling of the superfluid density with respect to @xmath3 for the sizes of @xmath3 studied . however , our numerical results can be collapsed onto a single curve by introducing an effective thickness @xmath7 ( where @xmath8 is a constant ) into the corresponding scaling relations . we argue that the effective thickness depends on the type of boundary conditions . scaling of the specific heat does not require an effective thickness ( within error bars ) and we find good agreement between the scaling function @xmath9 calculated from our monte carlo results , @xmath9 calculated by renormalization group methods , and the experimentally determined function @xmath10 . . And you have already written the first three sentences of the full article: the theory of second order phase transitions is based on the assumption that at temperatures close to the critical temperature @xmath6 there is only one dominating length scale associated with the critical behavior of the system , the correlation length . since the correlation length diverges as the critical temperature is approached the microscopic details of the system are irrelevant for its critical behavior . this intuitive picture has its foundation in the renormalization group treatment of second order phase transitions . within the renormalization group treatment. Please generate the next two sentences of the article

it becomes evident that the critical behavior can be divided into different universality classes . each universality class is characterized by a set of critical exponents which describe the singular behavior of physical quantities in terms of the reduced temperature @xmath11 , e.g. for a three - dimensional bulk system the correlation length @xmath12 diverges close to @xmath6 as @xmath13 .

Suppose that you have an abstract for a scientific paper: in this work the degree of entanglement of two - photon states generated by parametric - down conversion with a phase mismatch is computed in terms of the temperature of the nonlinear medium where the interaction takes place . the minimum interaction time , named _ birth time of entanglement _ , needed before entanglement is attained , is computed in terms of the temperature and of the phase mismatch . our results show that , for each value of the phase mismatch , there is a critical temperature above which entanglement disappears . we are able to identify the regions of parameters , temperature and mismatch , where the states are entangled and where they are separable . we also propose a entanglement witness based in a dynamical invariant of the nonlinear interaction . pacs number(s ) 03.67.a , 42.50-p . , 42.65.lm . And you have already written the first three sentences of the full article: a significant number of quantum computation and quantum information protocols use the quadrature amplitudes of the quantized electromagnetic field @xcite , @xcite . the essence of all these protocols rely in the possibility of producing entangled photons in a nonlinear medium @xcite . the parametric down conversion ( pdc ) @xcite is one of the most often used processes for production of entangled pairs of photons . however , as for many nonlinear optical processes , pdc is ruled by phase matching whose importance was early recognized @xcite , theoretical treatment of a phase mismatch that occurs during the propagation in the nonlinear medium is complicated and several approximations have been made @xcite , in order to relate the phase mismatch , with the amount of quantum correlations in the spontaneous emission of photons . at room temperatures. Please generate the next two sentences of the article

the average number of photons at optical frequencies is very small ( on the order of @xmath0 ) . however , in the microwave part of the spectrum the number of thermal photons initially present in the nonlinear medium can not be ignored and we expect that they will play a determinant role in the amount of entanglement that can be extracted from the interaction . to our knowledge a comprehensive study of pdc processes with a phase mismatch and at finite temperature of the nonlinear medium has not been addressed . in this paper

Suppose that you have an abstract for a scientific paper: by means of _ ab initio _ calculations , we have investigated the effect of h adsorption on the structural , electronic and magnetic properties of ultrathin co films on ru(0001 ) . our calculations predict that h occupies hollow sites preserving the two - dimensional 3-fold symmetry . the formation of a complete h overlayer leads to a very stable surface with strong h - co bonds . h tends to suppress surface features , in particular , the enhancement of the magnetic moments of the bare film . the h - induced effects are mostly confined to the co atoms bonded to h , independent of the h coverage or of the thickness and the structure of the co film . however , for partial h coverages a significant increase occurs in the magnetic moment for the surface co atoms not bonded to h , leading to a net enhancement of surface magnetism . . And you have already written the first three sentences of the full article: hydrogen is an ubiquitous element , present even in ultra - high - vacuum chambers , although very difficult to detect . it shows a large sticking probability in most transition metal surfaces @xcite , among them co. adsorption of h on transition metals was intensively studied in the past decades , mainly motivated by the understanding of the action of residual gases in catalytic and embrittlement processes . much less attention has been paid to the influence of h on the magnetic properties , though it is known to have a remarkable effect .. Please generate the next two sentences of the article

for example , the adsorption of h@xmath0 molecules on the surface of magnetic transition metals produces a reduction of surface magnetism @xcite . in addition , h coverage shifts the critical thickness for the spin reorientation transition ( srt ) of ni films @xcite , and a reversible manipulation of the magnetic exchange coupling of fe / v superlattices can be achieved upon loading the v layers with h @xcite . previous experimental results characterizing the structure and energetics of h adsorption on different co surfaces and nanostructures with two - dimensional ( 2d ) 3-fold symmetry , as co(0001 ) @xcite or co nanoislands on cu(111 ) @xcite , indicate that h prefers adsorption sites preserving the symmetry of the 2d lattice .

Suppose that you have an abstract for a scientific paper: _ an experimental study on the design of counter - rotating axial - flow fans was carried out . the fans were designed using an inverse method . in particular , the system is designed to have a pure axial discharge flow . the counter - rotating fans operate in a ducted - flow configuration and the overall performances are measured in a normalized test bench . the rotation rate of each fan is independently controlled . the relative axial spacing between fans can vary from @xmath0 to @xmath1 . the results show that the efficiency is strongly increased compared to a conventional rotor or to a rotor - stator stage . the effects of varying the rotation rates ratio on the overall performances are studied and show that the system has a very flexible use , with a large patch of high efficient operating points in the parameter space . the increase of axial spacing causes only a small decrease of the efficiency _ . And you have already written the first three sentences of the full article: early studied in the 1930 s @xcite , the counter - rotating machines arouse a greater interest in the turbomachinery field , particularly for their potential improvement of the efficiency with respect to conventional machines by recovering kinetic energy from the front rotor exit - flow and by adding energy to the flow . the first counter - rotating machines have appeared in aeronautic @xcite and marine applications @xcite in open configuration . conventional designs of high speed counter - rotating fans are based on quite expensive methods and require a systematic coming and going between theoretical methods such as the lifting line theory or the strip - analysis approach @xcite and cfd analysis @xcite .. Please generate the next two sentences of the article

moreover , the axial spacing , which has a major role on the rotors interaction and consequently on the noise @xcite , is a key parameter to find a compromise between high aerodynamic and good acoustic performance for high speed fans @xcite . in order to reduce this interaction , the axial spacing of high speed fans has to be relatively large , resulting in a decrease in the aerodynamic performance @xcite .

Suppose that you have an abstract for a scientific paper: in this note we present a general approach to construct large digraphs from small ones . these are called expanded digraphs , and , as particular cases , we show the close relationship between lifted digraphs of voltage digraphs and line digraphs , which are two known ways to obtain dense digraphs . in the same context , we show the equivalence between the vertex - splitting and partial line digraph techniques . then , we give a sufficient condition for a lifted digraph of a base line digraph to be again a line digraph . some of the results are illustrated with two well - known families of digraphs . namely , the de bruijn and kautz digraphs , where it is shown that both families can be seen as lifts of smaller de bruijn digraphs with appropriate voltage assignments . _ keyword : _ digraph , adjacency matrix , regular partition , quotient digraph , voltage digraphs , lifted digraph , partial line digraphs , vertex - split digraphs . _ mathematics subject classifications : _ 05c20 , 05c50 , 15a18 . . And you have already written the first three sentences of the full article: in the study of interconnection and communication networks , the theory of digraphs plays a key role because , in many cases , the links between nodes are unidirectional . in this theory , there are three concepts that have shown to be very fruitful to construct good and efficient networks . namely , those of quotient digraphs , voltage digraphs and ( partial ) line digraphs . roughly speaking , quotient digraphs allow us to obtain a simplified or ` condensed ' version of a bigger digraph , while the voltage and line digraph techniques do the converse by ` expanding ' a smaller digraph . from this point of view , it is natural that the three techniques have close relationships . in this paper. Please generate the next two sentences of the article

we explore some of such interrelations by introducing a general construction that we call expanded digraphs . these digraphs are obtained from a base graph whose vertices become vertex sets in the new graph , and the adjacencies are defined from a set of mappings .

Suppose that you have an abstract for a scientific paper: we study the general - setting quantum geometric phase acquired by a particle in a vibrating cavity . solving the two - level theory with the rotating - wave approximation and the su(2 ) method , we obtain analytic formulae that give excellent descriptions of the geometric phase , energy , and wavefunction of the resonating system . in particular , we observe a sudden @xmath0-jump in the geometric phase when the system is in resonance . we found similar behaviors in the geometric phase of a spin-1/2 particle in a rotating magnetic field , for which we developed a geometrical model to help visualize its evolution . . And you have already written the first three sentences of the full article: the dynamics of confined cavity fields interacting with the cavity wall is of great interest for the understanding of a variety of problems such as hadron bag models @xcite , sonoluminescence @xcite , cavity qed @xcite and black hole radiations @xcite . most previous studies on dynamical cavity concentrated on scalar or photon fields @xcite , which despite the apparent simplicity , exhibit rich and complex dynamics . in contrast , the system of a schrdinger particle in an oscillating spherical cavity has not gained as much attention . in this article. Please generate the next two sentences of the article

, we study the generalized quantum geometric phase of a particle in resonance with the vibrating cavity . we will show that the geometric phase acquires sudden @xmath0-jumps when the particle makes transitions .

Suppose that you have an abstract for a scientific paper: we report on accurate measurements of the scalar @xmath0 and tensor @xmath1 polarizabilities of the 5d fine structure levels 5d@xmath2 and 5d@xmath3 in rb . the measured values ( in atomic units ) @xmath4 , @xmath5 , @xmath6 and @xmath7 show reasonable correspondence to previously published theoretical predictions , but are more accurate . we implemented laser excitation of the 5d level in a laser cooled cloud of optically polarized rb-87 atoms placed in a constant electric field . @xmath8e - mail : ss@rqc.ru . And you have already written the first three sentences of the full article: study of atomic and molecular polarizabilities remains an important task in atomic physics . the atomic polarizability @xmath9 depends on electric dipole matrix elements @xmath10 @xcite which also describe transition strengths , state lifetimes , van der waals interactions , and scattering cross - sections . here @xmath11 denotes an electric dipole operator , @xmath12 the level energy with quantum number @xmath13 , and @xmath14 its wave functions . accurate measurements of polarizability facilitate progress in sophisticated atomic structure calculations and the theory of heavy atoms which results in more precise predictions for other important atomic parameters ( see e.g. @xcite ) .. Please generate the next two sentences of the article

measurements of polarizabilities become even more crucial in applications for modern optical atomic clocks . predictions of the `` magic '' wavelength in optical lattice clocks @xcite and accurate estimation of the blackbody radiation shift require precise knowledge of static and dynamic polarizabilities @xcite .

Suppose that you have an abstract for a scientific paper: we develope the holographic mean field approach in a bottom - up holographic qcd model including baryons and scalar mesons in addition to vector mesons and pions . we study the effect of parity doubling structure of baryons at non - zero density to the equation of state between the chemical potential and the baryon number density . we first show that we can adjust the amount of nucleon mass coming from the chiral symmetry breaking by changing the boundary value of the five - dimensional baryon fields . then , introducing the mean field for the baryon fields , we calculate the equation of state between the baryon number density and its corresponding chemical potential . then , comparing the predicted equation of state with the one obtained in a walecka type model , we extract the density dependence of the effective nucleon mass . the result shows that the effective mass decreases with increasing density , and that the rate of decreasing is more rapid for larger percentage of the mass from the chiral symmetry breaking . . And you have already written the first three sentences of the full article: the spontaneous chiral symmetry breaking ( @xmath0sb ) is one of the most important features in low - energy qcd . this is considered to be the origin of several hadron masses , such as the lightest nucleon mass . however , there is a possibility that only a part of the lightest nucleon mass is generated by the spontaneous @xmath0sb and the remaining part is the chiral invariant mass . this structure is nicely expressed in so called parity doublet models ( see , e.g. refs .. Please generate the next two sentences of the article

@xcite ) . it is an interesting question to ask how much amount of the nucleon mass is generated by the spontaneous @xmath0sb , or to investigate the origin of nucleon mass . studying dense baryonic matter

Suppose that you have an abstract for a scientific paper: we derive a simple and general relation between the fidelity of quantum motion , characterizing the stability of quantum dynamics with respect to arbitrary static perturbation of the unitary evolution propagator , and the integrated time auto - correlation function of the generator of perturbation . surprisingly , this relation predicts the slower decay of fidelity the faster decay of correlations is . in particular , for non - ergodic and non - mixing dynamics , where asymptotic decay of correlations is absent , a qualitatively different and faster decay of fidelity is predicted on a time scale @xmath0 as opposed to mixing dynamics where the fidelity is found to decay exponentially on a time - scale @xmath1 , where @xmath2 is a strength of perturbation . a detailed discussion of a semi - classical regime of small effective values of planck constant @xmath3 is given where classical correlation functions can be used to predict quantum fidelity decay . note that the correct and intuitively expected classical stability behavior is recovered in the classical limit @xmath4 , as the two limits @xmath5 and @xmath4 do not commute . in addition we also discuss non - trivial dependence on the number of degrees of freedom . all the theoretical results are clearly demonstrated numerically on a celebrated example of a quantized kicked top . to appear in ( march 2002 ) . And you have already written the first three sentences of the full article: the precise quantum signatures of different qualitative types of classical motion and the very definition of chaos in quantum mechanics are still the issues of an unsettled discussion ( see e.g. @xcite ) . due to unitarity of quantum dynamics , quantum chaos can not be defined in the same way as the classical chaos @xcite , namely through the exponential sensitivity on the variation of initial conditions . however , peres @xcite proposed an alternative concept which can be used in classical as well as in quantum mechanics : one can study the stability of quantum motion with respect to a small variation in the hamiltonian , or more generally , a variation of the unitary evolution operator . clearly , in classical mechanics this concept , when applied to individual trajectories ( or to phase space distribution functions as we show below in sect . 4 ) , is equivalent to the sensitivity to initial conditions : integrable systems with regular orbits are stable against small variation in the hamiltonian ( the statement of kam theorem ) , where s for chaotic orbits varying the hamiltonian has a similar effect as varying the initial condition : exponential divergence of two orbits for two nearby chaotic hamiltonians .. Please generate the next two sentences of the article

this paper is devoted to a systematic theoretical study of the stability of a unitary time evolution with respect to small static variations of the unitary propagator . it will be primarily applied to the schr " odinger propagator in quantum dynamics ( sect . 2 and 3 ) ,

Suppose that you have an abstract for a scientific paper: we calculate the _ exact _ landau - zener transitions probabilities for a qubit with arbitrary linear coupling to a bath at zero temperature . the final quantum state exhibits a peculiar entanglement between the qubit and the bath . in the special case of a diagonal coupling , the bath does not influence the transition probability , whatever the speed of the landau - zener sweep . it is proposed to use landau - zener transitions to determine both the reorganization energy and the integrated spectral density of the bath . possible applications include circuit qed and molecular nanomagnets . quite a number of quantum two - state systems are presently tested as candidate qubits , the units of quantum information . good qubits are well isolated from their environment , but easy to manipulate . this somewhat conflicting requirement has spurred renewed interest in the dynamics of qubits coupled to an environment or heat bath @xcite . qubits can be seen as bath detectors . for example , static qubits probe via their decay rates the bath spectral density at their transition frequencies . in solid - state environments these rates can be strongly frequency- and sample - dependent . we discuss an in this respect superior ` bath detection mode ' of the qubit . one way of changing the state of a two - level system involves the forced crossing of its diabatic energies . for constant level - crossing speed this is known as the landau - zener ( lz ) problem @xcite , which for a two - level system can be solved exactly @xcite . this is no longer the case when taking its environment into account @xcite that may cause thermal excitation and quantum tunneling . in the low - temperature tunneling regime , analytical estimates for transition probabilities exist only for very fast and very slow sweeps , and the literature is not unanimous about the latter limit @xcite . in another line of research , incited by the paper @xcite , it was recently proven that lz transition probabilities can be.... And you have already written the first three sentences of the full article: consider lz transitions in a qubit coupled to a bath of @xmath0 quantum harmonic oscillators , as described by the hamiltonian @xmath1 with the qubit - oscillator coupling @xmath2(b_{j}+b_{j}^{\dag}).\ ] ] the energy difference between the diabatic qubit states changes linearly in time as @xmath3 ( with level - crossing speed @xmath4 and their intrinsic interaction amplitude is @xmath5 . the @xmath6 are pauli operators . the first two terms of ( [ e.ham1 ] ) define the standard landau - zener problem for an isolated two - level system .. Please generate the next two sentences of the article

the @xmath0 harmonic oscillators in ( [ e.ham1 ] ) can have different frequencies @xmath7 , qubit - oscillator couplings @xmath8 , and interaction angles @xmath9 . the oscillators affect the qubit ( i ) by changing its energies via the diagonal coupling @xmath10 , and ( ii ) by inducing transitions between its levels via the transverse coupling @xmath11 . in order to calculate the probability that the qubit state flips due to the lz sweep

Suppose that you have an abstract for a scientific paper: we study the relaxation process in normal and anomalous diffusion regimes for systems described by a generalized langevin equation ( gle ) . we demonstrate the existence of a very general correlation function which describes the relaxation phenomena . such function is even ; therefore , it can not be an exponential or a stretched exponential . however , for a proper choice of the parameters , those functions can be reproduced within certain intervals with good precision . we also show the passage from the non - markovian to the markovian behaviour in the normal diffusion regime . for times longer than the relaxation time , the correlation function for anomalous diffusion becomes a power law for broadband noise . . And you have already written the first three sentences of the full article: the research on the striking universality properties of slow relaxation dynamics has been driving great efforts in the last decades . a large and growing literature can be found in which non - exponential behaviour has been observed for correlation functions : supercooled colloidal systems @xcite , glasses and granular material @xcite , liquid crystal polymers @xcite , hydrated proteins @xcite , growth @xcite , plasmas @xcite and disordered vortex lattices in superconductors @xcite are just a few examples . those systems present features which are similar to those found in systems with anomalous diffusion .. Please generate the next two sentences of the article

the attempt to obtain response functions which are able to explain such relaxation processes is a subject more than a hundred years old . rudolph kohlrausch used stretched exponentials @xmath0 $ ] with @xmath1 to describe charge relaxation in a leyden gas @xcite .

Suppose that you have an abstract for a scientific paper: we have searched for the decay @xmath0 and measured an upper limit for the inclusive branching fraction of @xmath1 at the 90% confidence level . this limit is small compared with the total expected @xmath2 rate . assuming factorization , the @xmath3 decay constant is constrained to be @xmath4 mev at the 90% confidence level , at least 2.5 times smaller than that of @xmath5 . 6.5 in 9.0 in -0.50 in 0.00 in 0.00 in m. bishai,@xmath6 j. fast,@xmath6 j. w. hinson,@xmath6 n. menon,@xmath6 d. h. miller,@xmath6 e. i. shibata,@xmath6 i. p. j. shipsey,@xmath6 m. yurko,@xmath6 s. glenn,@xmath7 s. d. johnson,@xmath7 y. kwon,@xmath8 s. roberts,@xmath7 e. h. thorndike,@xmath7 c. p. jessop,@xmath9 k. lingel,@xmath9 h. marsiske,@xmath9 m. l. perl,@xmath9 v. savinov,@xmath9 d. ugolini,@xmath9 r. wang,@xmath9 x. zhou,@xmath9 t. e. coan,@xmath10 v. fadeyev,@xmath10 i. korolkov,@xmath10 y. maravin,@xmath10 i. narsky,@xmath10 v. shelkov,@xmath10 j. staeck,@xmath10 r. stroynowski,@xmath10 i. volobouev,@xmath10 j. ye,@xmath10 m. artuso,@xmath11 f. azfar,@xmath11 a. efimov,@xmath11 m. goldberg,@xmath11 d. he,@xmath11 s. kopp,@xmath11 g. c. moneti,@xmath11 r. mountain,@xmath11 s. schuh,@xmath11 t. skwarnicki,@xmath11 s. stone,@xmath11 g. viehhauser,@xmath11 x. xing,@xmath11 j. bartelt,@xmath12 s. e. csorna,@xmath12 v. jain,@xmath13 k. w. mclean,@xmath12 s. marka,@xmath12 r. godang,@xmath14 k. kinoshita,@xmath14 i. c. lai,@xmath14 p. pomianowski,@xmath14 s. schrenk,@xmath14 g. bonvicini,@xmath15 d. cinabro,@xmath15 r. greene,@xmath15 l. p. perera,@xmath15 g. j. zhou,@xmath15 b. barish,@xmath16 m. chadha,@xmath16 s. chan,@xmath16 g. eigen,@xmath16 j. s. miller,@xmath16 c. ogrady,@xmath16 m. schmidtler,@xmath16 j. urheim,@xmath16 a. j. weinstein,@xmath16 f. wrthwein,@xmath16 d. w. bliss,@xmath17 g. masek,@xmath17 h. p. paar,@xmath17 s. prell,@xmath17 v. sharma,@xmath17 d. m. asner,@xmath18 j. gronberg,@xmath18 t. s. .... And you have already written the first three sentences of the full article: one of the outstanding issues in @xmath35 meson physics is the semileptonic branching fraction puzzle . experimentally @xmath36 is measured to be ( @xmath37)% @xcite , whereas theoretical calculations have difficulties accommodating a branching fraction below @xmath38 @xcite . one way to reduce the theoretical expectations is through a two - fold enhancement in the assumed @xmath39 rate @xcite , which is estimated to be @xmath40 from the measured inclusive rates for @xmath41 and @xmath42 .. Please generate the next two sentences of the article

recently , buchalla _ et al._@xcite and blok _

Suppose that you have an abstract for a scientific paper: we study linear theory of the magnetized rayleigh - taylor instability in a system consisting of ions and neutrals . both components are affected by a uniform vertical gravitational field . we consider ions and neutrals as two separate fluid systems where they can exchange momentum through collisions . however , ions have direct interaction with the magnetic field lines but neutrals are not affected by the field directly . the equations of our two - fluid model are linearized and by applying a set of proper boundary conditions , a general dispersion relation is derived for our two superposed fluids separated by a horizontal boundary . we found two unstable modes for a range of the wavenumbers . it seems that one of the unstable modes corresponds to the ions and the other one is for the neutrals . both modes are reduced with increasing the collision rate of the particles and the ionization fraction . we show that if the two - fluid nature is considered , rt instability would not be suppressed and also show that the growth time of the perturbations increases . as an example , we apply our analysis to the local clouds which seems to have arisen because of the rt instability . assuming that the clouds are partially ionized , we find that the growth rate of these clouds increases in comparison to a fully ionized case . . And you have already written the first three sentences of the full article: rayleigh - taylor ( rt ) instability occurs when a heavy fluid is supported by a lighter fluid in a gravitational field , or , equivalently , when a heavy fluid is accelerated by a lighter fluid . rt instability and the related processes have found applications in various astronomical systems , such as the expansion of supernova remnants ( e.g. , ribeyre et al . 2004 ) ( where inertial acceleration plays the role of the gravitational field ) , the interiors of red giants ( e.g. , chairborne and lagard 2010 ) , the radio bubbles in galaxy clusters ( pizzolato and soker 2006 ) .. Please generate the next two sentences of the article

the evolution of the rt instability is influenced by many different factors . for example , viscosity tends to reduce the growth rate and to stabilize the system ( e.g. , chandrasekhar 1961 ) .

Suppose that you have an abstract for a scientific paper: the higgs boson may decay mainly to an invisible mode characterized by missing energy , instead of the standard model channels . this is a generic feature of many models where neutrino masses arise from the spontaneous breaking of ungauged lepton number at relatively low scales , such as spontaneously broken r - parity models . taking these models as framework , we reanalyze this striking suggestion in view of the recent data on neutrino oscillations that indicate non - zero neutrino masses . we show that , despite the smallness of neutrino masses , the higgs boson can decay mainly to the invisible goldstone boson associated to the spontaneous breaking of lepton number . this requires a gauge singlet superfield coupling to the electroweak doublet higgses , as in the next to minimal supersymmetric standard model ( nmssm ) scenario for solving the @xmath0-problem . the search for invisibly decaying higgs bosons should be taken into account in the planning of future accelerators , such as the large hadron collider and the next linear collider . . And you have already written the first three sentences of the full article: understanding the origin of mass is the main open puzzle in particle physics today . in the standard model all masses arise as a result of the spontaneous breaking of the 1 gauge symmetry . this implies the existence of an elementary higgs boson , not yet found .. Please generate the next two sentences of the article

stabilizing the mass of the higgs most likely requires new physics and supersymmetry has so far been the leading contender . another aspect of this problem is the smallness of neutrino masses . despite the tremendous effort that has led to the discovery of neutrino mass @xcite the mechanism of neutrino mass generation will remain open for years to come ( a detailed analysis of the three

Suppose that you have an abstract for a scientific paper: we present a rotationally invariant hirsch - fye quantum monte carlo algorithm in which the spin rotational invariance of hund s exchange is approximated by averaging over all possible directions of the spin quantization axis . we employ this technique to perform benchmark calculations for the two- and three - band hubbard models on the infinite - dimensional bethe lattice . our results agree quantitatively well with those obtained using the continuous - time quantum monte carlo method with rotationally invariant coulomb interaction . the proposed approach is employed to compute the electronic and magnetic properties of paramagnetic @xmath0 iron and nickel . the obtained curie temperatures agree well with experiment . our results indicate that the magnetic transition temperature is significantly overestimated by using the density - density type of coulomb interaction . . And you have already written the first three sentences of the full article: the theoretical description of the electronic properties of transition metal compounds with partially filled @xmath1 and @xmath2-shells and strong coulomb interaction between the electrons remains a challenging , fundamental problem in condensed matter physics . @xcite the interplay between electronic and lattice degrees of freedom in such materials results in their diverse physical properties and rich phase diagrams making these compounds particularly attractive for technological applications . @xcite moreover , orbital degeneracy is an important and often inevitable cause of this complexity .. Please generate the next two sentences of the article

together with the hund s exchange interaction , it has important implications for the electronic and magnetic properties of correlated materials , leading to formation of local moments and complicated multiplet structures . the electronic properties of correlated materials can be understood by employing the so - called lda+dmft approach , @xcite a combination of _ ab initio _ local density approximation ( lda ) of the density functional theory and dynamical mean - field theory ( dmft ) .

Suppose that you have an abstract for a scientific paper: december monocerotids and november orionids are weak but established annual meteor showers active throughout november and december . analysis of a high quality orbits subset of the sonotaco video meteor database shows that the distribution of orbital elements , geocentric velocity and also the orbital evolution of the meteors and potential parent body may imply a common origin for these meteors coming from the parent comet c/1917 f1 mellish . this is also confirmed by the physical properties and activity of these shower meteors . an assumed release of meteoroids at the perihelion of the comet in the past and the sky - plane radiant distribution reveal that the december monocerotid stream might be younger than the november orionids . a meteoroid transversal component of ejection velocity at the perihelion must be larger than 100 m/s . a few authors have also associated december canis minorids with the comet c/1917 f1 mellish . however , we did not find any connection . [ firstpage ] comets , individual : c/1917 f1 mellish meteors , meteoroids celestial mechanics catalogues . And you have already written the first three sentences of the full article: the comet c/1917 f1 mellish , formerly designated as @xmath0 or @xmath1 , was discovered by j.e . mellish on march 20 , 1917 and was observed for 96 days @xcite from many places on the earth . in the southern hemisphere , the comet reached up to + 1 magnitude .. Please generate the next two sentences of the article

astronomer j.f . skjellerup noted that the brightness of the cometary head was about + 3 magnitude , with the diffuse coma and narrow tail about 10@xmath2 long on april 19 , 1917 @xcite .

Suppose that you have an abstract for a scientific paper: we examine several online matching problems , with applications to internet advertising reservation systems . consider an edge - weighted bipartite graph @xmath0 , with partite sets @xmath1 . we develop an @xmath2-competitive algorithm for the following secretary problem : initially given @xmath3 , and the size of @xmath4 , the algorithm receives the vertices of @xmath4 sequentially , in a random order . when a vertex @xmath5 is seen , all edges incident to @xmath6 are revealed , together with their weights . the algorithm must immediately either match @xmath6 to an available vertex of @xmath3 , or decide that @xmath6 will remain unmatched . in @xcite , the authors show a 16-competitive algorithm for the transversal matroid secretary problem , which is the special case with weights on vertices , not edges . ( equivalently , one may assume that for each @xmath7 , the weights on all edges incident to @xmath6 are identical . ) we use a similar algorithm , but simplify and improve the analysis to obtain a better competitive ratio for the more general problem . perhaps of more interest is the fact that our analysis is easily extended to obtain competitive algorithms for similar problems , such as to find disjoint sets of edges in hypergraphs where edges arrive online . we also introduce secretary problems with adversarially chosen _ groups_. finally , we give a @xmath8-competitive algorithm for the secretary problem on graphic matroids , where , with edges appearing online , the goal is to find a maximum - weight acyclic subgraph of a given graph . . And you have already written the first three sentences of the full article: many optimization problems of interest can be phrased as picking a maximum - weight independent subset from a ground set of elements , for a suitable definition of independence . a well - known example is the ( maximum - weight ) independent set problem on graphs , where we wish to find a set of vertices , no two of which are adjacent . a more tractable problem in this setting is the maximum - weight matching problem , in which we wish to find a set of edges such that no two edges share an endpoint .. Please generate the next two sentences of the article

this notion of independence can be naturally extended to hypergraphs , where a set of hyperedges is considered independent if no two hyperedges share a vertex . in the previous examples , independent sets are characterized by forbidding certain _ pairs _ of elements from the ground set .

Suppose that you have an abstract for a scientific paper: we analyze the high temperature spin dynamics of compass models using a moment expansion . we point out that the evaluation of moments maps to the enumeration of paths in a branching process on the lattice . this mapping to a statistical mechanics combinatorics problem provides an elegant visualization of the analysis . we present results for the time dependent spin correlation function ( which is of relevance to nmr experiments ) for two compass models : the kitaev honeycomb model and two - dimensional compass model . . And you have already written the first three sentences of the full article: over the years compass models have proved especially useful in the modeling of materials with multi - orbital degrees of freedom@xcite ; these hamiltonians describe fictitious spin degrees of freedom that have fully anisotropic spatial interactions@xcite . currently they are very prominent in both theoretical and experimental studies of the physics of iridium - oxide materials@xcite , the @xmath0rucl@xmath1 compound@xcite and finally the purported application of the kitaev model@xcite to quantum computing . neutron scattering@xcite and nmr experiments@xcite have provided convincing evidence that kitaev model physics dominates the effective hamiltonian describing @xmath0rucl@xmath1 , although the inclusion of further interactions , especially heisenberg exchange , seem to be necessary for a consistent description of the experiments .. Please generate the next two sentences of the article

additionally , thermal conductivity experiments could shed more light on the relevant interactions in these exotic quantum magnets . the standard theoretical approach to the spin dynamics analysis of the kitaev model is the elegant and powerful majorana fermion solution@xcite .

Suppose that you have an abstract for a scientific paper: since the discovery of cosmic acceleration , modified gravity theories play an important role in the modern cosmology . in particular , the well - known f(r)-theories reached great popularity motivated by the easier formalism and by the prospect to find a final theories of gravity for the dark scenarios . in the present work , we study some generalizations of f(r ) and f(t ) gravity theories . at the beginning , we briefly review the formalism of such theories . then , we will consider one of their generalizations , the so - called f(r , t)-theory . the point - like lagrangian is explicitly presented . based on this lagrangian , the field equations of f(r , t)-gravity are found . for the specific model @xmath0 the corresponding exact solutions are derived . furthermore , we will consider the physical quantities associated to such solutions and we will find how for some values of the parameters the expansion of our universe can be accelerated without introducing any dark component . . And you have already written the first three sentences of the full article: recent observational data imply -against any previous belief- that the current expansion of the universe is accelerating @xcite . since this discovery , the so - called dark energy issue has probably become the most ambitious and tantalizing field of research because of its implications in fundamental physics . there exist several descriptions of the cosmic acceleration . among them , the simplest one is the introduction of small positive cosmological constant in the framework of general relativity ( gr ) , the so - called @xmath1cdm model , but it is well accepted the idea according to which this is not the ultimate theory of gravity , but an extremely good approximation valid in the present day range of detection .. Please generate the next two sentences of the article

a generalization of this simple modification of gr consists in considering modified gravitational theories @xcite . in the last years the interest in modified gravity theories like @xmath2 and @xmath3-gravity as alternatives to the @xmath1cdm model grew up .

Suppose that you have an abstract for a scientific paper: we present sub - millimeter statistical detections of galaxies discovered in the @xmath0 spitzer early release observations ( to @xmath1jy @xmath2 at @xmath3 m , @xmath4jy at @xmath5 m ) through a stacking analysis of our reanalysed scuba 8mjy survey maps , and a spitzer identification of a new sub - millimeter point source in the 8mjy survey region . for sources detected at @xmath6 m or @xmath7 m ( @xmath8 and @xmath9 sources respectively ) , we detect positive skews in the sub - millimeter flux distributions at @xmath10 confidence using kolmogorov - smirnov tests , at both @xmath11 m and @xmath12 m . we also marginally detect the _ spitzer _ @xmath5 m galaxies at @xmath11 m at @xmath13 confidence , and place limits on the mean sub - millimeter fluxes of the @xmath14 m and @xmath15 m sources . integrating the sub - millimeter fluxes of the _ spitzer _ populations , we find the @xmath6 m galaxies contribute @xmath16 nw m@xmath17 sr@xmath18 to the @xmath11 m background , and @xmath19 nw m@xmath17 sr@xmath18 to the @xmath12 m background ; similar contributions are made by the @xmath7m - selected sample . we infer that the populations dominating the @xmath6 m and @xmath7 m extragalactic background light also contribute around a quarter of the @xmath11 m background and the majority of the @xmath12 m background . . And you have already written the first three sentences of the full article: the early pioneering sub - millimeter surveys in lensing clusters ( smail , ivison & blain 1997 ) and in blank fields ( hughes et al . 1998 , barger et al . 1998 ) demonstrated the feasibility of deep extragalactic surveys exploiting the favorable k - corrections in the sub - millimeter . deep @xmath11 m imaging has now resolved around half of the @xmath11 m extragalactic background ( hughes et al .. Please generate the next two sentences of the article

1998 , blain et al . 1999 , cowie , barger & kneib 2002 ) .

Suppose that you have an abstract for a scientific paper: multi connected universe models with space idenfication scales smaller than the size of the observable universe produce topological images in the catalogs of cosmic sources . in this review , we present the recent developments for the search of the topology of the universe focusing on three dimensional methods . we present the crystallographic method , we give a new lower bound on the size of locally euclidean multi connected universe model of @xmath0 based on this method and a quasar catalog , we discuss its successes and failures , and the attemps to generalise it . we finally introduce a new statistical method based on a collecting correlated pair ( ccp ) technique . email : uzan@amorgos.unige.ch , roller@discovery.saclay.cea.fr , jean-pierre.luminet@obspm.fr . And you have already written the first three sentences of the full article: in the standard cosmological framework , the universe is decribed by a friedmann - lemaitre solution , the spatial sections of which being usually assumed to be simply connected . einstein equations being local , they allow us to determine the local geometry but they give no complete information about the global structure of the universe , i.e. about its topology , even if the geometry constrains to some extent the topology . this was pointed out by friedmann himself just after he proposed its cosmological solution @xcite .. Please generate the next two sentences of the article

the indeterminacy about the global topology of the cosmological solutions was raised out as soon as einstein proposed the first cosmological solution of his equations ; the einstein static universe assumed spatial sections with the topology of the hypersphere @xmath1 @xcite , although de sitter stressed that the same geometry could admit as well the projective space @xmath2 as spatial sections @xcite . these two solutions were locally identical ( same metric ) but differed by their topology , i.e. by the choice of boundary conditions .

Suppose that you have an abstract for a scientific paper: we study the markovianity of a composite system and its subsystems . we show how the dissipative nature of a subsystem s dynamics can be modified without having to change properties of the composite system environment . by preparing different system initial states or dynamically manipulating the subsystem coupling , we find that it is possible to induce a transition from markov to non - markov behavior , and _ vice versa_. . And you have already written the first three sentences of the full article: the theory of open quantum systems plays a central role in the description of realistic quantum systems due to unavoidable interaction with the environment . as is well known , the system - environment interaction can lead to energy dissipation and decoherence @xcite , posing a major challenge to the development of modern technologies based on quantum coherence @xcite . due to its fundamental character and practical implications , the investigation of dissipative processes has been a subject of vigorous research , where the standard approach assumes a system - environment weak coupling and a memoryless quantum dynamics ( the born - markov approximation ) . under such assumptions ,. Please generate the next two sentences of the article

system dynamics are determined by a quantum markovian master equation , i.e. , a completely positive quantum dynamical map with a generator in the lindblad form @xcite . although the markovian approach has been widely used , there is a growing interest in understanding and controlling non - markovianity . in quantum metrology ,

Suppose that you have an abstract for a scientific paper: we consider a set of coupled underdamped ac - driven dynamical units exposed to a heat bath . the coupling scheme defines the absence / presence of certain symmetries , which in turn cause a nonzero / zero value of a mean dc - output . we discuss dynamical mechanisms of a dc - current appearance and identify current reversals with synchronization / desynchronization transitions in the collective ratchet s dynamics . driven underdamped systems ; synchronization ; ratchet effect 05.45.ac , 05.60.cd . And you have already written the first three sentences of the full article: the _ ratchet _ effect , i. e. the possibility to obtain the directed transport by using zero - mean perturbations only , has induced notable scrutiny over the last decade [ 1 ] . initially , most studies have been focused on noisy overdamped models have been inspired by a molecular motors realm [ 1 ] . then the ratchet s approach has been applied to a broad class of physical systems in which inertia effects are essential [ 2 ] . the examples are josepshon junctions [ 3 ] , cold atoms systems [ 4 ] , and mechanical engines [ 5 ] .. Please generate the next two sentences of the article

recently it has been shown that the ratchet idea can be viewed as a part of a general symmetry - breaking approach [ 6 ] . this approach is based on the analysis of all relevant symmetries which have to be broken in order to fulfill necessary conditions for a dc - output appearance .

Suppose that you have an abstract for a scientific paper: we present a coupled boltzmann and hydrodynamics approach to relativistic heavy ion reactions . this hybrid approach is based on the ultra - relativistic quantum molecular dynamics ( urqmd ) transport approach with an intermediate hydrodynamical evolution for the hot and dense stage of the collision . event - by - event fluctuations are directly taken into account via the non - equilibrium initial conditions generated by the initial collisions and string fragmentations in the microscopic urqmd model . after a ( 3 + 1)-dimensional ideal hydrodynamic evolution , the hydrodynamical fields are mapped to hadrons via the cooper - frye equation and the subsequent hadronic cascade calculation within urqmd proceeds to incorporate the important final state effects for a realistic freeze - out . this implementation allows to compare pure microscopic transport calculations with hydrodynamic calculations using exactly the same initial conditions and freeze - out procedure . the effects of the change in the underlying dynamics - ideal fluid dynamics vs. non - equilibrium transport theory - will be explored . the freeze - out and initial state parameter dependences are investigated for different observables . furthermore , the time evolution of the baryon density and particle yields are discussed . we find that the final pion and proton multiplicities are lower in the hybrid model calculation due to the isentropic hydrodynamic expansion while the yields for strange particles are enhanced due to the local equilibrium in the hydrodynamic evolution . the results of the different calculations for the mean transverse mass excitation function , rapidity and transverse mass spectra for different particle species at three different beam energies are discussed in the context of the available data . . And you have already written the first three sentences of the full article: one of the main motivations to study high energy heavy ion collisions is the creation of a new deconfined phase of strongly interacting matter , the so called quark - gluon plasma ( qgp ) @xcite . at the relativistic heavy ion collider ( rhic ) many experimental observations like , e.g. , jet quenching and high elliptic flow hint to the fact that a strongly coupled qgp ( sqgp ) might have been created @xcite . at cern - sps energies evidence for the creation of a new state of matter has been published , e.g. , the enhanced k/@xmath0 ratio ( horn ) and the step in the mean transverse mass excitation function for pions , kaons and protons @xcite . especially the low energy ( high @xmath1 ) program at sps showed a culmination of exciting results. Please generate the next two sentences of the article

. therefore this energy regime will be the subject to further detailed studies at the cern - sps , bnl - rhic , jinr - nica and at the fair facility . since the direct detection of free quarks and gluons is impossible due to the confining nature of qcd , it is important to model the dynamical evolution of heavy ion reactions to draw conclusions from the final state particle distributions about the interesting early stage of the reaction .

Suppose that you have an abstract for a scientific paper: we study the effect of the non - linear process of ambipolar diffusion ( joint transport of magnetic flux and charged particles relative to neutral particles ) on the long - term behavior of a non - uniform magnetic field in a one - dimensional geometry . our main focus is the dissipation of magnetic energy inside neutron stars ( particularly magnetars ) , but our results have a wider application , particularly to the interstellar medium and the loss of magnetic flux from collapsing molecular cloud cores . our system is a weakly ionized plasma in which neutral and charged particles can be converted into each other through nuclear beta decays ( or ionization - recombination processes ) . in the `` weak - coupling '' limit of infrequent inter - particle interactions , the evolution of the magnetic field is controlled by the beta decay rate and can be described by a non - linear partial integro - differential equation . in the opposite , `` strong - coupling '' regime , the evolution is controlled by the inter - particle collisions and can be modelled through a non - linear diffusion equation . we show numerically that , in both regimes , ambipolar diffusion tends to spread out the magnetic flux , but , contrary to the normal ohmic diffusion , it produces sharp magnetic field gradients with associated current sheets around those regions where the magnetic field is weak . diffusion plasmas magnetohydrodynamics ( mhd ) ism : magnetic fields stars : magnetic fields stars : neutron . And you have already written the first three sentences of the full article: ambipolar diffusion is the joint drift of charged particles and the associated magnetic flux with respect to the neutral particles in a partially ionized plasma . @xcite first proposed it in order to explain the loss of magnetic flux from the dense cores of molecular clouds , required for the formation of stars , starting an active field of research in this area . later , it was suggested to also play a role in the decay of the magnetic fields of neutron stars ( @xcite , hereafter gr-92 ) which became particularly relevant with the identification of `` magnetars '' , neutron stars whose main power source appears to be the dissipation of their magnetic field @xcite . in a previous paper ( @xcite ; hereafter paper i ) , we established a multifluid formalism in which it is possible to study the long - term evolution of magnetic fields in neutron stars ( see @xcite for a discussion of the main properties of the magnetic field equilibria and their subsequent long - term evolution ) . in that work , and following the ideas developed by gr-92 , we included the effects of several physical processes that are also relevant for star formation and protoplanetary disks , including _. Please generate the next two sentences of the article

ambipolar diffusion _ , _ hall drift _ ( non - dissipative advection of the magnetic field by the associated electrical current ) , and _ ohmic diffusion _ ( dissipation of currents through the electrical resistivity ) .

Suppose that you have an abstract for a scientific paper: we investigate the structure of hybrid stars based on two different constructions : one is based on the gibbs condition for phase coexistence and considers the existence of a mixed phase ( mp ) , and the other is based on the maxwell construction and no mixed phase is obtained . the hadron phase is described by the non - linear walecka model ( nlw ) and the quark phase by the nambu - jona - lasinio model ( njl ) . we conclude that the masses and radii obtained are model dependent but not significantly different for both constructions . pacs number(s ) : 24.10.jv , 26.60+c . And you have already written the first three sentences of the full article: understanding the processes involved in the supernova explosions , in the creation of stellar compact objects and in their temporal evolution requires a huge multidisciplinary effort with investigations in areas as distinct as nuclear and particle physics , thermodynamics , quantum field theory and astrophysics . in the present work we concentrate on the description of neutron stars . from very low densities up to the high densities present in their core , the constitution of these compact objects is a great source of speculation . at low densities there can be neutrons , protons , electrons and possibly neutrinos ( at finite temperatures ) . at high densities ,. Please generate the next two sentences of the article

stellar matter can be much more complex , including hyperons , kaons and even deconfined quarks . many works considering the construction of equations of state ( eos ) used to describe compact objects have already been done @xcite .

Suppose that you have an abstract for a scientific paper: the model - independent method based on the triangle ideology is implemented to extract the ckm - matrix angle @xmath0 in the decays of doubly heavy baryons containing the charmed and beauty quarks . we analyze a color structure of diagrams and conditions for reconstructing two reference - triangles by tagging the flavor and cp eigenstates of @xmath1 mesons in the fixed exclusive channels . the characteristic branching ratios are evaluated in the framework of a potential model setting a parametric dependence on the hadronic matrix elements for the decay rates . . And you have already written the first three sentences of the full article: the current success in the experimental study of decays with the cp - violation in the gold - plated mode of neutral @xmath2-meson by the babar and belle collaborations @xcite allows one to extract the ckm - matrix angle @xmath3 in the unitarity triangle by the model - independent method . the intensive efforts are intended in the physical programs on the @xmath2 and @xmath4 mesons at the hadron colliders both the active tevatron @xcite and prospective lhc . due to the relatively high cross - sections the doubly heavy hadrons such as the @xmath5 meson and baryons @xmath6 , @xmath7 and @xmath8 , @xmath7 would be copiously produced at such the machines @xcite .. Please generate the next two sentences of the article

in addition to the indirect or model - dependent measurements of unitarity triangle @xcite , there is an intriguing opportunity to extract the angle @xmath0 in the model - independent way using the strategy of reference triangles @xcite in the decays of doubly heavy hadrons . this ideology for the study of cp - violation in @xmath5 decays was originally offered by m.masetti @xcite and investigated by r.fleischer and d.wyler @xcite . in this letter

Suppose that you have an abstract for a scientific paper: we present an application of a new formalism to treat the quantum transport properties of fully interacting nanoscale junctions [ phys . rev . b * 84 * , 235428 ( 2011 ) ] . we consider a model single - molecule nanojunction in the presence of two kinds of electron - vibron interactions . in terms of electron density matrix , one interaction is diagonal in the central region and the second is off - diagonal in between the central region and the left electrode . we use a non - equilibrium green s function technique to calculate the system s properties in a self - consistent manner . the interaction self - energies are calculated at the hartree - fock level in the central region and at the hartree level for the crossing interaction . our calculations are performed for different transport regimes ranging from the far off - resonance to the quasi - resonant regime , and for a wide range of parameters . they show that a non - equilibrium ( i.e. bias dependent ) static ( i.e. energy independent ) renormalisation is obtained for the nominal hopping matrix element between the left electrode and the central region . such a renormalisation is highly non - linear and non - monotonic with the applied bias , however it always lead to a reduction of the current , and also affects the resonances in the conductance . furthermore , we show that the relationship between the non - equilibrium charge susceptibility and dynamical conductance still holds even in the presence of crossing interaction . . And you have already written the first three sentences of the full article: the theory of quantum transport in nano - scale devices has evolved rapidly over the past decade , as advances in experimental techniques have made it possible to probe transport properties ( at different temperatures ) down to the single - molecule scale . furthermore simultaneous measurement of charge and heat transport through single molecules is now also possible @xcite . the development of accurate theoretical methods for the description of quantum transport at the single - molecule level is essential for continued progress in a number of areas including molecular electronics , spintronics , and thermoelectrics .. Please generate the next two sentences of the article

one of the longstanding problems of quantum charge transport is the establishment of a theoretical framework which allows for quantitatively accurate predictions of conductance from first principles . the need for methods going beyond the standard approach based on density functional theory combined with landauer - like elastic scattering @xcite has been clear for a number of years .

Suppose that you have an abstract for a scientific paper: spin - polarons are obtained using an ising - like exchange model consisting of double and super - exchange interactions in low dimensional systems . at zero temperature , a new phase separation between small magnetic polarons , one conduction electron self - trapped in a magnetic domain of two or three sites , and the anti - ferromagnetic phase was previously reported . on the other hand the important effect of temperature was missed . temperature diminishes boltzmann probability allowing excited states in the system . static magnetic susceptibility and short - range spin - spin correlations at zero magnetic field were calculated to explore the spin - polaron formation . at high temperature curie - weiss behavior is obtained and compared with the curie - like behavior observed in the nickelate one - dimensional compound @xmath0 . exchange and super - exchange interactions , classical spin models , phase separation 75.30.et,75.10.hk,64.75.+g . And you have already written the first three sentences of the full article: phase transition in a given physico - chemical system is characterized by parameters like the range of the microscopic interactions , the space dimensionality @xmath1 and the dimensionality of the order parameter , often referred to the spin dimensionality @xmath2 . there are features whose qualitative nature is determined by the universality class to which the system belongs . short - range interactions , double and super - exchange nearest - neighbor type , classical and quantum spins @xmath2 in @xmath1-dimensional systems have been studied @xcite .. Please generate the next two sentences of the article

double - exchange ( de ) interaction or indirect exchange , is the source of a variety of magnetic behavior in transition metal and rare - earth compounds@xcite . the origin of de lies in the intra - atomic coupling of the spin of itinerant electrons with localized spins @xmath3 .

Suppose that you have an abstract for a scientific paper: the lightest @xmath0 state , @xmath1 @xmath2 , also known as roper resonance , has puzzled physicists for decades . a large variety of theoretical models aimed to understand its properties have been proposed . some of them are briefly reviewed here , together with the hadronic processes where the roper resonance is revealed or plays an important role . . And you have already written the first three sentences of the full article: in the 1950ies , fermi and coworkers started to measure pion - nucleon cross sections and to analyze the data in terms of partial waves , leading the way to the discovery of a large number of baryon resonances . in 1963 , in a partial - wave analysis performed at the lawrence livermore national laboratory , l. d. roper found a @xmath2 resonance at @xmath3 gev ( @xmath4 mev pion laboratory kinetic energy ) @xcite . the result was surprizing as there were no hints for such a state and the @xmath2 scattering length is rather large and negative . in words of roper : _ i spent a much time trying to eliminate the @xmath2 resonance _ @xcite . the particle data group estimates for the main @xmath5 properties are listed in table [ tab1 ] .. Please generate the next two sentences of the article

l r + + + [ 0.05 cm ] + + [ 0.2 cm ] decay modes & fraction ( @xmath6 ) + @xmath7 & 0.55 to 0.75 + @xmath8 & @xmath9 % + @xmath10 & @xmath11 % + @xmath12 & @xmath13 8 % + @xmath14 & @xmath15 % + @xmath16 & @xmath17 % + @xmath18 & @xmath19 % + considerable uncertainties are apparent , specially in the full breit - wigner width and the branching ratios to the strong - decay channels . indeed , different values are obtained with different models , most of them built in terms of breit - wigner resonances plus background , meson - exchange or @xmath20-matrix formalisms .

Suppose that you have an abstract for a scientific paper: nanoparticles can influence the properties of polymer materials by a variety of mechanisms . with fullerene , carbon nanotube , and clay or graphene sheet nanocomposites in mind , we investigate how particle shape influences the melt shear viscosity @xmath0 and the tensile strength @xmath1 , which we determine via molecular dynamics simulations . our simulations of compact ( icosahedral ) , tube or rod - like , and sheet - like model nanoparticles , all at a volume fraction @xmath2 , indicate an order of magnitude increase in the viscosity @xmath0 relative to the pure melt . this finding evidently can not be explained by continuum hydrodynamics and we provide evidence that the @xmath0 increase in our model nanocomposites has its origin in chain bridging between the nanoparticles . we find that this increase is the largest for the rod - like nanoparticles and least for the sheet - like nanoparticles . curiously , the enhancements of @xmath0 and @xmath1 exhibit _ opposite trends _ with increasing chain length @xmath3 and with particle shape anisotropy . evidently , the concept of bridging chains alone can not account for the increase in @xmath1 and we suggest that the deformability or flexibility of the sheet nanoparticles contributes to nanocomposite strength and toughness by reducing the relative value of the poisson ratio of the composite . we note the molecular dynamics simulations in the present work focus on the reference case where the modification of the melt structure associated with glass - formation and entanglement interactions should not be an issue . since many applications require good particle dispersion , we also focus on the case where the polymer - particle interactions favor nanoparticle dispersion . our simulations point to a substantial contribution of nanoparticle shape to both mechanical and processing properties of polymer nanocomposites . . And you have already written the first three sentences of the full article: blends of polymers and nanoparticles , commonly called `` polymer nanocomposites '' ( pnc ) , have garnered much attention due to the possibility of dramatic improvement of polymeric properties with the addition of a relatively small fraction of nanoparticles @xcite . successfully making use of these materials depends upon a firm understanding of both their mechanical and flow properties . numerous computational and theoretical studies have examined the clustering and network formation of nanoparticles and their effect on both the structural and rheological properties of pncs @xcite . the vast majority of these efforts have focused on nanoparticles that are either spherical , polyhedral or otherwise relatively symmetric , although there are some notable exceptions @xcite . in contrast. Please generate the next two sentences of the article

, experiments have tended to emphasize highly asymmetric nanoparticles @xcite , such as layered silicates or carbon nanotubes . it is generally appreciated that these highly asymmetric nanoparticles have the potential to be even more effective than spherical ( or nearly spherical ) nanoparticles in changing the properties of the polymer matrix to which they are added .

Suppose that you have an abstract for a scientific paper: we performed the fabry - perot scanning interferometry of the quartet of galaxies ngc 7769 , 7770 , 7771 and 7771a in h@xmath0 line and studied their velocity fields . we found that the rotation curve of ngc 7769 is weakly distorted . the rotation curve of ngc 7771 is strongly distorted with the tidal arms caused by direct flyby of ngc 7769 and flyby of a smaller neighbor ngc 7770 . the rotation curve of ngc 7770 is significantly skewed because of the interaction with much massive ngc 7771 . the rotation curves and morphological disturbances suggest that the ngc 7769 and ngc 7771 have passed the first pericenter stage , however , probably the second encounter has not happened yet . . And you have already written the first three sentences of the full article: we report the results of the optical interferometry of the interacting system of galaxies ngc 7769 , 7770 , 7771 and 7771a and analyze their kinematics . a detailed description of the morphological features of the galaxies as well as photometry and color analysis of ngc 7769 are presented in the complete version of the study : @xcite . we also discuss the influence of interaction on the kinematics , dynamics and star formation in the system .. Please generate the next two sentences of the article

known models of galaxy interactions are based mostly on statistical observational data . we try to illustrate how and to what extend these models can be applied to explain the features of the galaxies in this system . in order to study the velocity fields of the galaxies ,

Suppose that you have an abstract for a scientific paper: we present simulation results of @xmath0 + jet analysis using cms ( compact muon solenoid ) object - oriented software at the large hadron collider ( lhc ) center of mass energy @xmath1=14 tev . the study of direct photon production helps in validating the perturbative quantum chromodynamics ( pqcd ) and providing information on the gluon distribution in the nucleons . direct photon processes also constitute a major background to several other standard model ( sm ) processes and signals of new physics . thus these processes need to be understood precisely in the new energy regime . in this work , we have done a detailed study of the geant4 simulated @xmath0 + jet events generated with pythia , and the related background processes . isolation cuts have been optimized for direct photon which improves the signal over background ratio by @xmath2 as compared to previous studies done in cms . the inclusion of a large @xmath3 cut between the photon and the leading jet at @xmath4 in the analysis leads to a further increase of @xmath5 in s / b , thus giving an overall gain of @xmath6 in s / b ratio . = 100000 # 1(#1 ) 1t_1 cms - note-2007/004 + accepted in european journal of physics c * study of direct photon plus jet production in cms experiment at @xmath1=14 tev * + pooja gupta , b.c.choudhary , s.chatterji,and s.bhattacharya + department of physics and astrophysics , university of delhi , + delhi , 110 007 , india + 1.0 cm . And you have already written the first three sentences of the full article: direct or prompt photons are photons that emerge directly from the hard scattering of the partons and not from secondary decays or as the radiation product of initial or final state partons . since these photons come directly from parton - parton hard scattering , they provide a clean signature of the underlying hard scattering dynamics . prompt photon production in hadronic interactions provides a precision test of pqcd predictions as well as information on the gluon density inside the colliding hadrons . theoretical investigations have shown@xcite that the cross - section for direct photon production has a pseudorapidity ( @xmath7 ) dependence which is sensitive to the parameterization of the gluon distributions@xcite .. Please generate the next two sentences of the article

the lhc energy will provide an opportunity to determine gluon density in a proton in new kinematic region of @xmath8 and @xmath9 ( @xmath10)@xcite . the analysis of the lhc data in combination with results from the tevatron and hera would allow to extend the qcd analysis in @xmath9 region @xmath11@xcite . the study of physics beyond the sm at the lhc also requires a complete understanding of the qcd processes .

Suppose that you have an abstract for a scientific paper: we review the calculation of the hoyle state of @xmath0c in nuclear lattice effective field theory ( nleft ) and its anthropic implications for the nucleosynthesis of @xmath0c and @xmath1o in red giant stars . we also review the extension of nleft to the regime of medium - mass nuclei , with emphasis on the determination of the ground - state energies of the alpha nuclei @xmath1o , @xmath2ne , @xmath3 mg and @xmath4si by means of euclidean time projection . finally , we review recent nleft results for the spectrum , electromagnetic properties , and alpha - cluster structure of @xmath1o . . And you have already written the first three sentences of the full article: nuclear lattice effective field theory ( nleft ) is a first - principles approach , in which chiral eft for nucleons is combined with numerical auxiliary - field quantum monte carlo ( afqmc ) lattice calculations . nleft differs from other _ ab initio _ methods @xcite in that it is an unconstrained monte carlo calculation , which does not rely on truncated basis expansions or many - body perturbation theory , nor on prior information about the structure of the nuclear wave function . as in chiral eft ,. Please generate the next two sentences of the article

our calculations are organized in powers of a generic soft scale @xmath5 associated with factors of momenta and the pion mass @xcite . we denote @xmath6 as leading order ( lo ) , @xmath7 as next - to - leading order ( nlo ) , and @xmath8 as next - to - next - to - leading order ( nnlo ) contributions .

Suppose that you have an abstract for a scientific paper: the statistics of large - scale structure in the universe can be used to probe non - gaussianity of the primordial density field , complementary to existing constraints from the cosmic microwave background . in particular , the scale dependence of halo bias , which affects the halo distribution at large scales , represents a promising tool for analyzing primordial non - gaussianity of local form . future observations , for example , may be able to constrain the trispectrum parameter @xmath0 that is difficult to study and constrain using the cmb alone . we investigate how galaxy and matter bispectra can distinguish between the two non - gaussian parameters @xmath1 and @xmath0 , whose effects give nearly degenerate contributions to the power spectra . we use a generalization of the univariate bias approach , making the hypothesis that the number density of halos forming at a given position is a function of the local matter density contrast and of its local higher - order statistics . using this approach , we calculate the halo - matter bispectra and analyze their properties . we determine a connection between the sign of the halo bispectrum on large scales and the parameter @xmath0 . we also construct a combination of halo and matter bispectra that is sensitive to @xmath1 , with little contamination from @xmath0 . we study both the case of single and multiple sources to the primordial gravitational potential , discussing how to extend the concept of stochastic halo bias to the case of bispectra . we use a specific halo mass - function to calculate numerically the bispectra in appropriate squeezed limits , confirming our theoretical findings . . And you have already written the first three sentences of the full article: the intrinsic non - gaussianity of primordial curvature perturbations is a valuable tool to distinguish among different models for the origin of structure in the very early universe @xcite . even if the primordial curvature perturbation has a gaussian distribution , the initial density perturbation is non - gaussian due to the non - linearity of the einstein field equations @xcite . non - gaussianity ( ng ) may be characterized by a variety of different parameters , which control the departure of the underlying probability distribution function ( pdf ) of primordial fluctuations from a purely gaussian distribution .. Please generate the next two sentences of the article

these parameters can be related to the amplitude of connected @xmath2-point ( @xmath2-pt ) correlation functions of primordial curvature fluctuations that vanish for @xmath3 in the gaussian case . the connected @xmath2-pt functions may be scale- and shape - dependent , in a manner determined by the particular model that generates them . in this work

Suppose that you have an abstract for a scientific paper: resonant magnetic perturbations ( rmps ) can mitigate the edge - localized modes ( elms ) , i.e. cause a change of the elm character towards smaller energy loss and higher frequency . during mitigation a change of the spatial structure of elm loads on divertor was observed on diii - d and mast : the power is deposited predominantly in the footprint structures formed by the magnetic perturbation . in the present contribution we develop a theory explaining this effect , based on the idea that part of the elm loss is caused by parallel transport in the homoclinic tangle formed by the magnetic perturbation of the elm . the modified tangle resulting from the combination of the elm perturbation and the applied rmp has the expected property of bringing open field lines in the same areas as the tangle from the rmp alone . we show that this explanation is consistent with features of the mitigated elms on mast . we in addition validated our theory by an analysis of simulations of mitigated elms using the code jorek . we produced detailed laminar plots of field lines on the divertor in the jorek runs with an elm , an applied rmp , and an elm mitigated by the presence of the rmp . the results for an elm clearly show a high - n rotating footprint structure appearing during the nonlinear stage of the elm , which is not present in the early stage of the elm . the results for a @xmath0 rmp from the elm control coils show the expected @xmath0 footprint structure . the results for the mitigated elm show a similar structure , modulated by a higher @xmath1 perturbation of the elm , consistent with our theory . . And you have already written the first three sentences of the full article: resonant magnetic perturbations ( rmps ) are one of the promising methods of edge - localized mode ( elm ) control in future tokamak reactors @xcite , which is necessary as already for iter it is predicted that at full plasma current uncontrolled elms can not be tolerated @xcite . the rmps either suppress the elms completely or cause a change of the elm character towards smaller energy loss and higher frequency @xcite . the latter effect is called elm mitigation and may be a viable option for elm control on iter if the reduction in peak heat load at the divertor is sufficient to protect the plasma - facing components . one major unknown parameter in the predictions of tolerable elm sizes is the elm wetted area , which together with the total elm loss determines the peak heat load on the plasma - facing components @xcite . the compatibility of mitigated elms with plasma - facing components is therefore not only determined by the elm energy loss reduction achieved , but also by any changes of the wetted area accompanying the mitigation @xcite . as an example , it was observed on mast that mitigation achieves a less significant reduction of peak elm heat load than of the total elm loss due to a concurrent reduction of the wetted area @xcite .. Please generate the next two sentences of the article

similar results were reported on jet with the carbon wall @xcite . on the contrary on jet with the iter - like wall the reduction of the peak heat load during elm mitigation was partly due to an increase of the wetted area @xcite .

Suppose that you have an abstract for a scientific paper: we have acquired deep , h - band , imaging for a sample of 286 virgo cluster galaxies with b@xmath0 mag and extracted surface photometry from optical @xmath1,@xmath2,@xmath3,@xmath4 sloan digital sky survey images of 742 virgo cluster catalog galaxies , including those with h - band images . we confirm the detection of a dip in the luminosity function indicative of a discontinuity in the cluster galaxy population ; the dip is more pronounced at redder wavelengths . we find , in agreement with earlier works of tully & verheijen and ours for ursa major cluster galaxies , a clear dichotomy between high and low surface brightness galaxy disks . the difference between the low and high brightness peaks of virgo disk galaxies is @xmath52 h - mag arcsec@xmath6 , significantly larger than any systematic errors . the high surface brightness disk galaxies have two distinct classes of high and low concentration bulges , while low surface brightness galaxies have only low concentration bulges . early - type galaxies exhibit a similar structural bimodality though offset from that of the spiral galaxies towards higher surface brightnesses . both the early- and late - type structural bimodalities are uncorrelated with colour or any other structural parameter except , possibly , circular velocity . random realizations of realistic surface brightness profiles suggest that a bimodal distribution of effective surface brightness is unexpected based on normal distributions of bulge and disk parameters . rather , the structural bimodality may be linked to dynamical properties of galaxies . low angular momentum systems may collapse to form dynamically important disks with high surface brightness , while high angular momentum systems would end up as low surface brightness galaxies dominated by the dark halo at all radii . the confirmation of structural bimodality for gas - rich and gas - poor galaxies in the high - density virgo cluster as well as the low - density uma cluster suggests that this phenomenon is.... And you have already written the first three sentences of the full article: the range of surface density profiles for galaxies in a cluster is a telltale of its dynamical history . for instance , an excess of cuspy profiles over , say , the mean field galaxy distribution , is indicative of recent merger activity . conversely , extended exponential profiles are representative of quiescent evolution over long timescales ( e.g. , toth & ostriker 1992 ) .. Please generate the next two sentences of the article

the study of galaxy light profiles has a rich history with seminal early contributions from de vaucouleurs ( 1948 ; 1959 ) , srsic ( 1968 ) , and freeman ( 1970 ) . de vaucouleurs ( 1948 ) established that the surface brightness ( hereafter sb ) profiles of early type stellar systems may follow a strongly concentrated distribution now referred to as the `` de vaucouleurs '' or `` @xmath7 '' profile .

Suppose that you have an abstract for a scientific paper: in this paper , we consider an expanding construction of a distributed control system , which is obtained by adding a new subsystem one after the other , until all @xmath0 subsystems , where @xmath1 , are included in the distributed control system . it is assumed that a small random perturbation enters only into the first subsystem and is then subsequently transmitted to the other subsystems . moreover , for any @xmath2 , the distributed control system , compatible with the expanding construction , which is obtained from the first @xmath3 subsystems , satisfies an appropriate hrmander condition . as a result of this , the diffusion process is degenerate , i.e. , the backward operator associated with it is a degenerate parabolic equation . our main interest here is to prevent the diffusion process ( that corresponds to a particular subsystem ) from leaving a given bounded open domain . in particular , we consider a risk - sensitive version of the mean escape time criterion with respect to each of the subsystems . using a variational representation , we characterize the risk - sensitive escape control for the diffusion process as the lower and upper values of an associated stochastic differential game . finally , we comment on the implication of our results , where one is also interested in evaluating the performance of the risk - sensitive escape control , when there is some modeling error in the distributed control system . . And you have already written the first three sentences of the full article: we consider the diffusion processes @xmath4 pertaining to the following distributed control system , with small random perturbations ( see fig . [ fig - dcs ] ) @xmath5 where * @xmath6 is an @xmath7-valued diffusion process that corresponds to the @xmath8th - subsystem ( with @xmath9 ) , * the functions @xmath10 are uniformly lipschitz , with bounded first derivatives , @xmath11 is a small positive number ( which is related to the random perturbation level in the system ) , * @xmath12 is lipschitz with the least eigenvalue of @xmath13 uniformly bounded away from zero , i.e. , @xmath14 for some @xmath15 , * @xmath16 ( with @xmath17 ) is a @xmath18-dimensional standard wiener process , * @xmath19 is a @xmath20-valued measurable control process to the @xmath8th - subsystem , i.e. , an admissible control from the measurable set @xmath21 . in this paper , we identify two admissible controls @xmath22 , for @xmath23 , being the same on @xmath24 $ ] if @xmath25 \bigr\ } = 1 $ ] . if @xmath26 , then , for every @xmath27 , there exists a borel measurable function @xmath28 , \mathbb{r}^m \bigr ) \rightarrow \mathcal{u}_i$ ] ( with respect to some underlying borel @xmath29-algebra ) such that @xmath30 , \label{eq2}\end{aligned}\ ] ] with probability one ( w.p.1 ) .. Please generate the next two sentences of the article

the functions @xmath31 , for @xmath2 , in equation , with any progressively measurable control @xmath32 , depend only on @xmath33 . furthermore , we assume that the distributed control system , which is formed by the first @xmath3 subsystems , satisfies an appropriate hrmander condition , i.e. , a hypoellipticity assumption on the diffusion processes @xmath34 ( e.g. , see @xcite or ( * ? ? ?

Suppose that you have an abstract for a scientific paper: the whipple 10 meter atmospheric cherenkov telescope has made observations of the region known as the cygnus arm . this region has been recently reported by the milagro experiment to contain a diffuse tev @xmath0-ray source centered at ra=308 and dec=42 . we report upper limits ( using the whipple 10 m telescope ) obtained during the fall 2004 observing season centered on ra=310 and dec=42.65 . . And you have already written the first three sentences of the full article: the milagro observatory@xcite has made long term observations of the cygnus arm . they report an excess of over 5.5@xmath1 over a 5.9@xmath2 square bin in ra and dec.@xcite . this excess is inconsistent with a point source and may be due to a giant molecular cloud(gmc ) located in the same region as the excess .. Please generate the next two sentences of the article

this cloud has been reported by dame et . al.@xcite to be at a distance of 1.7 pc with a estimated mass of @xmath3 .

Suppose that you have an abstract for a scientific paper: the anderson localization problem in one and two dimensions is solved analytically via the calculation of the generalized lyapunov exponents . this is achieved by making use of signal theory . the phase diagram can be analyzed in this way . in the one dimensional case all states are localized for arbitrarily small disorder in agreement with existing theories . in the two dimensional case for larger energies and large disorder all states are localized but for certain energies and small disorder extended and localized states coexist . the phase of delocalized states is marginally stable . we demonstrate that the metal - insulator transition should be interpreted as a first - order phase transition . consequences for perturbation approaches , the problem of self - averaging quantities and numerical scaling are discussed . . And you have already written the first three sentences of the full article: frequently problems arise in science which involve both additive and multiplicative noise . the first type is relatively easy to handle with the help of the central limit theorem . the situation changes dramatically with the appearance of multiplicative noise .. Please generate the next two sentences of the article

famous examples are the anderson localization , turbulence , and the kicked quantum rotator among others . in this field results of an importance comparable to the central limit theorem are still lacking .

Suppose that you have an abstract for a scientific paper: face analysis techniques have become a crucial component of human - machine interaction in the fields of assistive and humanoid robotics . however , the variations in head - pose that arise naturally in these environments are still a great challenge . in this paper , we present a real - time capable 3d face modelling framework for 2d in - the - wild images that is applicable for robotics . the fitting of the 3d morphable model is based exclusively on automatically detected landmarks . after fitting , the face can be corrected in pose and transformed back to a frontal 2d representation that is more suitable for face recognition . we conduct face recognition experiments with non - frontal images from the muct database and uncontrolled , in the wild images from the pasc database , the most challenging face recognition database to date , showing an improved performance . finally , we present our scitos g5 robot system , which incorporates our framework as a means of image pre - processing for face analysis . . And you have already written the first three sentences of the full article: among the technologies for biometric identification and verification , face recognition has become a widely - used method , as it is a non - intrusive and reliable method . however , the robustness of a facial recognition system is constrained by the degree of head pose that is involved and the recognition rates of state of the art systems drop significantly for large pose angles . especially for tasks where a great variation in head pose has to be expected , like in human - robot interaction , pose - invariant face recognition is crucial . the rise of collaborative and assistive robots in industrial and home environments will increase the demand for algorithms that can adapt to changing settings and uncontrolled conditions .. Please generate the next two sentences of the article

a humanoid robot s cognitive ability to interpret non - verbal communication during conversations relies also heavily on the face of the human counterpart . the impact of head pose on the face analysis performance can be minimised by using normalisation techniques that transform non - frontal faces into frontal representations .

Suppose that you have an abstract for a scientific paper: over the past two decades , large strides have been made in the field of planet formation . yet fundamental questions remain . here we review our state of understanding of five fundamental bottlenecks in planet formation . these are : 1 ) the structure and evolution of protoplanetary disks ; 2 ) the growth of the first planetesimals ; 3 ) orbital migration driven by interactions between proto - planets and gaseous disk ; 4 ) the origin of the solar system s orbital architecture ; and 5 ) the relationship between observed super - earths and our own terrestrial planets . given our lack of understanding of these issues , even the most successful formation models remain on shaky ground . . And you have already written the first three sentences of the full article: the origin of planets is a vast , complex and still quite mysterious subject . despite decades of space exploration , ground based observations and detailed analyses of meteorites and cometary grains ( the only space samples available in our laboratories ) it is still not clear how the planets of the solar system formed . the discovery of extrasolar planets has added confusion to the problem , bringing to light evidence that planetary systems are very diverse , that our solar system is not a typical case and that categories of planets that do nt exist in our system are common elsewhere ( e.g. the super - earth planets ) . there are several recent reviews on planet formation .. Please generate the next two sentences of the article

johansen et al . ( 2014 ) focused on planetesimal formation , morbidelli et al .

Suppose that you have an abstract for a scientific paper: a shear flow of particles in a laser - driven two - dimensional ( 2d ) dusty plasma are observed in a further study of viscous heating and thermal conduction . video imaging and particle tracking yields particle velocity data , which we convert into continuum data , presented as three spatial profiles : mean particle velocity ( i.e. , flow velocity ) , mean - square particle velocity , and mean - square fluctuations of particle velocity . these profiles and their derivatives allow a spatially - resolved determination of each term in the energy and momentum continuity equations , which we use for two purposes . first , by balancing these terms so that their sum ( i.e. , residual ) is minimized while varying viscosity @xmath0 and thermal conductivity @xmath1 as free parameters , we simultaneously obtain values for @xmath0 and @xmath1 in the same experiment . second , by comparing the viscous heating and thermal conduction terms , we obtain a spatially - resolved characterization of the viscous heating . = 1 . And you have already written the first three sentences of the full article: flows of most liquid substances are usually studied by modeling the liquid as a continuum , but there are some substances that allow the study of flows at the kinetic level , i.e. , at the level of the individual constituent particles . as examples , we can mention chute flows in granular materials @xcite and capillary flows in colloids @xcite . the solid particles in these soft materials are large enough that their motion can be tracked by video microscopy , allowing experimenters to record their positions and velocities . like granular materials and colloids , dusty plasmas also allow direct observation of individual particle motion .. Please generate the next two sentences of the article

dusty plasma @xcite is a four - component mixture consisting of micron - size particles of solid matter , neutral gas atoms , free electrons , and free positive ions . these particles of solid matter , which are referred to as `` dust particles , '' gain a large negative charge @xmath2 , which is about @xmath3 elementary charges under typical laboratory conditions .

Suppose that you have an abstract for a scientific paper: we discuss the non - relativistic limit of quantum field theory in an inertial frame , in the rindler frame and in the presence of a weak gravitational field , and attempt to highlight and clarify several subtleties . in particular , we study the following issues : ( a ) while the action for a _ relativistic _ free particle is invariant under the lorentz transformation , the corresponding action for a _ non - relativistic _ free particle is not invariant under the galilean transformation , but picks up extra contributions at the end points . this leads to an extra phase in the non - relativistic wave function under a galilean transformation , which can be related to the rest energy of the particle _ even in the non - relativistic limit_. we show that this is closely related to the peculiar fact that the relativistic action for a free particle remains invariant even if we restrict ourselves to @xmath0 in implementing the lorentz transformation . ( b ) we provide a brief critique of the principle of equivalence in the quantum mechanical context . in particular , we show how solutions to the generally covariant klein - gordon equation in a noninertial frame , which has a time - dependent acceleration , reduce to the non - relativistic wave function in the presence of an appropriate ( time - dependent ) gravitational field in the @xmath1 limit , and relate this fact to the validity of the principle of equivalence in a quantum mechanical context . we also show that the extra phase acquired by the _ non - relativistic _ wave function in an accelerated frame , actually arises from the gravitational time dilation and survives in the non - relativistic limit . ( c ) while the solution of the schrodinger equation can be given an interpretation as being the probability amplitude for a single particle , such an interpretation fails in quantum field theory . we show how , in spite of this , one can explicitly evaluate the path integral using the ( non - quadratic ) action for a relativistic particle (.... And you have already written the first three sentences of the full article: the fundamental principles of physics , as we understand them today , emphasize the role of three constants : @xmath2 ( newton s gravitational constant ) , @xmath3 ( the speed of light ) and @xmath4 ( the planck constant ) . by a suitable choice of units , we can set the numerical value of all these three to unity and the broad structure of physical theories can be represented using a 3-dimensional space in which each of the cartesian coordinates is taken to be one of the above mentioned fundamental constants ( see fig . [ fig : physicscube ] ) . it turns out to be convenient to use @xmath5 rather than @xmath3 in such a description , and the entire space of physical theories will be confined within the unit cube so formed .. Please generate the next two sentences of the article

the examination of this diagram reveals several interesting features . the origin @xmath6 represents an idealized non - relativistic ( point ) mechanics ( nrm ) with which many physics courses begin . moving along the speed of light axis to @xmath7 , ( keeping @xmath8 ) , will get us special relativistic ( sr ) mechanics .

Suppose that you have an abstract for a scientific paper: we discuss a recently proposed analytic solution to the thomas fermi ( tf ) equation and show that earlier approaches provide more accurate results . in particular , we show that a simple and straightforward rational approximation to the tf equation yields the slope at origin with unprecedented accuracy , as well as remarkable values of the tf function and its first derivative for other coordinate values . . And you have already written the first three sentences of the full article: the thomas fermi ( tf ) equation has proved useful for the treatment of many physical phenomena that include atoms@xcite , molecules@xcite , atoms in strong magnetic fields@xcite , crystals@xcite and dense plasmas@xcite among others . for that reason there has been great interest in the accurate solution of that equation , and , in particular , in the accurate calculation of the slope at origin@xcite . besides , the mathematical aspects of the tf equation have been studied in detail@xcite .. Please generate the next two sentences of the article

some time ago liao@xcite proposed the application of a technique called homotopy analysis method ( ham ) to the solution of the tf equation and stated that `` it is the first time such an elegant and explicit analytic solution of the thomas fermi equation is given '' . this claim is surprising because at first sight earlier analytical approaches are apparently simpler and seem to have produced much more accurate results@xcite .

Suppose that you have an abstract for a scientific paper: control of quantum dissipative systems can be challenging because control variables are typically part of the system hamiltonian , which can only generate motion along unitary orbits of the system . to transit between orbits , one must harness the dissipation super - operator . to separate the inter - orbit dynamics from the hamiltonian dynamics for a generic two - dimensional system , we project the lindblad master equation onto the set of spectra of the density matrix , and we interpret the location along the orbit to be a new control variable . the resulting differential equation allows us to analyze the controllability of a general two - dimensional lindblad system , particularly systems where the dissipative term has an anti - symmetric part . we extend this to categorize the possible purifiable systems in two dimensions . . And you have already written the first three sentences of the full article: recent decades have seen the application of mathematical control theory to quantum systems in both physics and chemistry , as technological advances have allowed for greater precision in manipulation of these systems @xcite@xcite@xcite@xcite@xcite . one particular area of interest is the possible construction of quantum computers , which have the power to perform algorithms not accessible to conventional computers . a major experimental obstacle to any implementation of such a computer , however , is the decoherence of the system under influence of the environment .. Please generate the next two sentences of the article

while much progress has been made on the control of closed quantum systems @xcite@xcite@xcite , work on open quantum systems has proved more challenging @xcite@xcite@xcite@xcite@xcite . one important issue is that controls are nearly always in the form of hamiltonian operators .

Suppose that you have an abstract for a scientific paper: the totally asymmetric simple exclusion process ( tasep ) is a well studied example of far - from - equilibrium dynamics . here , we consider a tasep with open boundaries but impose a global constraint on the total number of particles . in other words , the boundary reservoirs and the system must share a finite supply of particles . using simulations and analytic arguments , we obtain the average particle density and current of the system , as a function of the boundary rates and the total number of particles . our findings are relevant to biological transport problems if the availability of molecular motors becomes a rate - limiting factor . _ keywords _ : non - equilibrium statistical physics , totally asymmetric exclusion process , biological transport . And you have already written the first three sentences of the full article: over the last two decades , the study of driven diffusive systems kls , sz , vp , schutz has formed a significant branch in the general pursuit to understand non - equilibrium statistical mechanics . the underlying dynamics violates detailed balance , so that the long - time behavior is governed by a true _ non - equilibrium _ steady state ( ness ) . highly unexpected and non - trivial properties are manifested , even in one - dimensional systems with purely local dynamics .. Please generate the next two sentences of the article

a paradigmatic model in the last class is the totally asymmetric simple exclusion process ( tasep ) krug , derrida92,dehp , s1993,derrida , schutz . characterized by open boundaries and particle transport , it displays the key physical signatures of a system driven far from equilibrium .

Suppose that you have an abstract for a scientific paper: kernel - based mean shift ( ms ) trackers have proven to be a promising alternative to stochastic particle filtering trackers . despite its popularity , ms trackers have two fundamental drawbacks : ( 1 ) the template model can only be built from a single image ; ( 2 ) it is difficult to adaptively update the template model . in this work we generalize the plain ms trackers and attempt to overcome these two limitations . it is well known that modeling and maintaining a representation of a target object is an important component of a successful visual tracker . however , little work has been done on building a robust template model for kernel - based ms tracking . in contrast to building a template from a single frame , we train a robust object representation model from a large amount of data . tracking is viewed as a binary classification problem , and a discriminative classification rule is learned to distinguish between the object and background . we adopt a support vector machine ( svm ) for training . the tracker is then implemented by maximizing the classification score . an iterative optimization scheme very similar to ms is derived for this purpose . compared with the plain ms tracker , it is now much easier to incorporate on - line template adaptation to cope with inherent changes during the course of tracking . to this end , a sophisticated on - line support vector machine is used . we demonstrate successful localization and tracking on various data sets . = 1 kernel - based tracking , mean shift , particle filter , support vector machine , global mode seeking . . And you have already written the first three sentences of the full article: visual localization / tracking plays a central role for many applications like intelligent video surveillance , smart transportation monitoring systems . localization and tracking algorithms aim to find the most similar region to the target in an image . recently , kernel - based tracking algorithms @xcite have attracted much attention as an alternative to particle filtering trackers @xcite . one of the most crucial difficulties in robust tracking is the construction of representation models ( likelihood models in bayesian filtering trackers ) that can accommodate illumination variations , deformable appearance changes , partial occlusions , .. Please generate the next two sentences of the article

most current tracking algorithms use a single static template image to construct a target representation based on density models . for both kernel - based trackers and particle filtering trackers , a popular method is to exploit color distributions in simple regions ( region - wise density models ) .

Suppose that you have an abstract for a scientific paper: the morris - lecar ( ml ) model has applications to neuroscience and cognition . a simple network consisting of a pair of synaptically coupled ml neurons can exhibit a wide variety of deterministic behaviors including asymmetric amplitude state ( aas ) , equal amplitude state ( eas ) , and steady state ( ss ) . in addition , in the presence of noise this network can exhibit mixed - mode oscillations ( mmo ) , which represent the system being stochastically driven between these behaviors . in this paper , we develop a method to specifically estimate the parameters representing the coupling strength ( @xmath0 ) and the applied current ( @xmath1 ) of two reciprocally coupled and biologically similar neurons . this method employs conditioning the likelihood on cumulative power and mean voltage . conditioning has the potential to improve the identifiability of the estimation problem . conditioning likelihoods are typically much simpler to model than the explicit joint distribution , which several studies have shown to be difficult or impossible to determine analytically . we adopt a rejection sampling procedure over a closed defined region determined by bifurcation continuation analyses . this rejection sampling procedure is easily embedded within the proposal distribution of a bayesian markov chain monte carlo ( mcmc ) scheme and we evaluate its performance . this is the first report of a bayesian parameter estimation for two reciprocally coupled morris - lecar neurons , and we find a proposal utilizing rejection sampling reduces parameter estimate bias relative to naive sampling . application to stochastically coupled ml neurons is a future goal . . And you have already written the first three sentences of the full article: transmembrane voltage is often recorded during physiological study of biological neurons . however , voltage - gated ion channel activity and neurotransmitter levels are quite difficult to measure directly and are usually unobserved in such studies . in addition , there is a great diversity of neuron morphology , protein expression , and plasticity which may affect voltage dynamics and synaptic transmission @xcite . early development and senescence may also be major determinants of voltage response profiles @xcite . synaptic tuning in particular is thought to be an essential mediator of learning , stimulus response integration , and memory .. Please generate the next two sentences of the article

there is evidence that memory and learning may depend critically on several distinct types of dynamic behavior in the voltage of neurons . the ml model reproduces the voltage of a single neuron and , depending on parameterization and initial conditions , can exhibit many of the experimentally observed behaviors of biological neurons @xcite . in this paper , we explore a simple neural network consisting of two biologically identical , reciprocally coupled ml neurons . @xcite have shown that this modest model can exhibit a wide range of oscillating or non - oscillating voltage depending on the values of just a few parameters , specifically in this study , @xmath1and @xmath0 . in the absence of noise , the model can predict synchronous or asynchronous firing , as well as either equal or unequal action potential amplitudes .

Suppose that you have an abstract for a scientific paper: the eso slice project ( esp ) is a galaxy redshift survey we have recently completed as an eso key project . the esp covers 23.3 square degrees in a region close to the south galactic pole . the survey is nearly complete ( 85% ) to the limiting magnitude @xmath0 and consists of 3342 galaxies with reliable redshift determination . in this paper , the first in a series that will present the results of the esp survey , we describe the main characteristics of the survey and briefly discuss the properties of the galaxy sample . from a preliminary spectral analysis of a large sub sample of 2550 galaxies we find that the fraction of actively star forming galaxies increases from a few percent for the brightest galaxies up to about 40% for the galaxies fainter than @xmath1 . the most outstanding feature in the esp redshift distribution is a very significant peak at @xmath2 . the detection of similar peaks , at the same distance , in other surveys in the same region of the sky , suggests the presence of a large bidimensional structure perpendicular to the line of sight . the minimum size of this structure would be of the order of @xmath3 , comparable with the size of the great wall . 2[oii ] @xmath4 . And you have already written the first three sentences of the full article: in the course of the last decade redshift surveys have provided a major advance in our knowledge of the large scale distribution of galaxies and its statistical properties ( see for example the review of giovanelli and haynes 1991 ) . bright , wide angle surveys ( e.g. cfa2 , geller and huchra 1989 ; ssrs2 , da costa et al . 1994 ; perseus . Please generate the next two sentences of the article

pisces , giovanelli and haynes 1988 ) cover a large fraction of the sky and provide a clear picture of the nearby universe , up to about 10,000 km / s or @xmath5 ( where @xmath6 ) . these surveys reveal large structures in the distribution of galaxies : voids of sizes up to @xmath7 ( de lapparent et al .

Suppose that you have an abstract for a scientific paper: due to the ultrarelativistic velocity of the expanding `` fireshell '' ( lorentz gamma factor @xmath0 ) , photons emitted at the same time from the fireshell surface do not reach the observer at the same arrival time . in interpreting gamma - ray bursts ( grbs ) it is crucial to determine the properties of the equitemporal surfaces ( eqtss ) : the locus of points which are source of radiation reaching the observer at the same arrival time . in the current literature this analysis is performed only in the latest phases of the afterglow . here we study the distribution of the grb bolometric luminosity over the eqtss , with special attention to the prompt emission phase . we analyze as well the temporal evolution of the eqts apparent size in the sky . we use the analytic solutions of the equations of motion of the fireshell and the corresponding analytic expressions of the eqtss which have been presented in recent works and which are valid for both the fully radiative and the adiabatic dynamics . we find the novel result that at the beginning of the prompt emission the most luminous regions of the eqtss are the ones closest to the line of sight . on the contrary , in the late prompt emission and in the early afterglow phases the most luminous eqts regions are the ones closest to the boundary of the visible region . this transition in the emitting region may lead to specific observational signatures , i.e. an anomalous spectral evolution , in the rising part or at the peak of the prompt emission . we find as well an expression for the apparent radius of the eqts in the sky , valid in both the fully radiative and the adiabatic regimes . such considerations are essential for the theoretical interpretation of the prompt emission phase of grbs . . And you have already written the first three sentences of the full article: it is widely accepted that gamma - ray burst ( grb ) afterglows originate from the interaction of an ultrarelativistically expanding shell into the circumburst medium ( cbm ) . differences exists on the detailed kinematics and dynamics of such a shell ( see e.g. refs . and refs . therein ) . due to the ultrarelativistic velocity of the expanding shell ( lorentz gamma factor @xmath0 ) , photons emitted at the same time in the laboratory frame ( i.e. the one in which the center of the expanding shell is at rest ) from the shell surface but at different angles from the line of sight do not reach the observer at the same arrival time .. Please generate the next two sentences of the article

therefore , if we were able to resolve spatially the grb afterglows , we would not see the spherical surface of the shell . we would see instead the projection on the celestial sphere of the equitemporal surface ( eqts ) , defined as the surface locus of points which are source of radiation reaching the observer at the same arrival time ( see e.g. refs .

Suppose that you have an abstract for a scientific paper: color gradients in elliptical galaxies in distant clusters ( @xmath0 ) are examined by using the archival deep imaging data of wide field planetary camera 2 ( wfpc2 ) on - board the hubble space telescope ( hst ) . obtained color gradients are compared with the two model gradients to examine the origin of the color gradients . in one model , a color gradient is assumed to be caused by a metallicity gradient of stellar populations , while in the other one , it is caused by an age gradient . both of these model color gradients reproduce the average color gradient seen in nearby ellipticals , but predict significantly different gradients at a redshift larger than @xmath10.3 . comparison between the observed gradients and the model gradients reveals that the metallicity gradient is much more favorable as the primary origin of color gradients in elliptical galaxies in clusters . the same conclusion has been obtained for field ellipticals by using those at the redshift from 0.1 to 1.0 in the hubble deep field - north by tamura et al . ( 2000 ) . thus , it is also suggested that the primary origin of the color gradients in elliptical galaxies does not depend on galaxy environment . . And you have already written the first three sentences of the full article: it has been known that nearby elliptical galaxies have color gradients ; colors in an elliptical galaxy gradually become bluer with increasing radius ( e.g. , vader et al . 1988 ; franx , illingworth , & heckman 1989 ; peletier et al . 1990a ; peletier , valentijn , & jameson 1990b , goudfrooij et al . 1994 ; michard 1999 ) . since many of elliptical galaxies show radial gradients in metal absorption line strengths such as mg@xmath2 , fe@xmath3(5270 ) and fe@xmath2(5335 ) ( e.g. , carollo , danziger , & buson 1993 ; davies , sadler , & peletier 1993 ; gonzalez 1993 ; kobayashi & arimoto 1999 ) , the origin of the color gradients has been naively interpreted to be the metallicity gradients . however , such an interpretation for the origin of the color gradient is premature , because both metallicity gradient and age gradient in stellar population can cause the same color gradient , and we can not distinguish the cause for the gradient .. Please generate the next two sentences of the article

this is called _ age - metallicity degeneracy _ , which was originally pointed out by worthey , trager , & faber ( 1996 ) in terms of the origin of the color - magnitude relation of nearby elliptical galaxies ( see also arimoto 1996 ) . in order to break this degeneracy and to know the primary origin of the color gradients in elliptical galaxies , comparing the observed color gradients in distant ellipticals with predicted model gradients caused by either the metallicity gradient or the age gradient is a very effective approach , as was successful for examining the origin of the color - magnitude ( cm ) relation ( kodama & arimoto , 1997 ) .

Suppose that you have an abstract for a scientific paper: euso - ta is a pathfinder experiment for the space based jem - euso mission for the detection of ultra - high energy cosmic rays . euso - ta is an high - resolution fluorescence telescope installed in front of the black rock mesa fluorescence detectors of the telescope array ( ta ) experiment , in utah ( usa ) . at the ta site , a central laser facility is installed for calibration purposes , since it emits laser beams with known energy and geometry . euso - ta consists of two 1 @xmath0 fresnel lenses , with a field of view of that focus the light on a photo detector module ( pdm ) . the pdm currently consists of 36 hamamatsu multi - anode photo - multipliers tubes ( mapmts ) with 64 channels each . front - end readout is performed by 36 asics , with two fpga boards that send the data to a cpu and a storage system . the detector was installed in february 2015 . tests using the mentioned light sources have been performed and observations of cosmic ray events , as well as those of stars with different magnitude and color index have been done . the data acquisition is triggered by ta fluorescence detectors , although a self - trigger algorithm is currently in the last phases of development and test . with ta , thanks to its large field of view and the surface detectors , the cosmic ray shower events are reconstructed and the parameters are used to perform simulations of the response of euso - ta detector using _ offline_. simulations of the detected events are compared with data and the results are shown in this work . . And you have already written the first three sentences of the full article: euso - ta @xcite is a pathfinder detector of the jem - euso project @xcite . the aim of jem - euso is to detect the rare ultra - high energy cosmic rays ( uhecrs ) from space , observing the uv fluorescence light emitted by cosmic ray extensive air showers ( eass ) through the atmosphere , which is used as an huge calorimeter . + the purpose of the euso - ta experiment is to validate some aspects of the observation principle of jem - euso detecting eass from ground .. Please generate the next two sentences of the article

indeed , it is located at the telescope array ( ta ) @xcite site in utah ( usa ) , in front of the black rock mesa fluorescence detectors ( brm - fds ) station @xcite , both visible in fig . [ fig : euso - ta - site ] .

Suppose that you have an abstract for a scientific paper: we investigate the ratchet dynamics of nonlinear klein - gordon kinks in a periodic , asymmetric lattice of point - like inhomogeneities . we explain the underlying rectification mechanism within a collective coordinate framework , which shows that such system behaves as a rocking ratchet for point particles . careful attention is given to the kink width dynamics and its role in the transport . we also analyze the robustness of our kink rocking ratchet in the presence of noise . we show that the noise activates unidirectional motion in a parameter range where such motion is not observed in the noiseless case . this is subsequently corroborated by the collective variable theory . an explanation for this new phenomenom is given . . And you have already written the first three sentences of the full article: the study of transport mechanisms at the mesoscale level is of great importance nowadays . specifically , the so - called ratchet systems have shown to be proper candidates for explaining unidirectional motion to biological systems @xcite , and have important physical applications for nano- and micro - scale technologies @xcite . many of these models have been developed in the simple picture of point - like particles @xcite ( see the reviews @xcite for details ) .. Please generate the next two sentences of the article

such scenario has been subsequently generalized to spatially extended systems @xcite , where much attention has been paid to situations where the net motion arises through time - symmetry breaking @xcite . this kind of ratchet phenomenon has been recently observed in long josephson junction ( ljj ) devices @xcite .

Suppose that you have an abstract for a scientific paper: existing data on @xmath0cu - nuclear spin relaxation reveal two independent relaxation processes : the one that is temperature independent we link to incommensurate peaks seen by neutrons , while the universal temperature dependent contribution coincides with @xmath1 for two - chain ybco 124 . we argue that this new result substitutes for a pseudogap regime in a broad class of high-@xmath2 cuprates and stems from the 1st order phase transition that starts well above the superconductivity @xmath2 but becomes frustrated because of broken electroneutrality in the cuo@xmath3 plane . superconductivity , pseudogap , magnetic properties , nmr . And you have already written the first three sentences of the full article: one of the most intriguing normal properties of the high-@xmath2 ( ht@xmath4 ) cuprates is the so called pseudogap ( pg ) phenomenon . it is commonly presented in the @xmath5 plane as a line that starts from rather high temperatures ( at small @xmath6 ) and reaches the superconductivity ( sc ) @xmath2 dome below at or above optimal @xmath7 . in a broad sense @xmath6. Please generate the next two sentences of the article

means the hole concentration in the cuo@xmath3- plane , but more often than not one refers to properties of the sr - doped la@xmath8sr@xmath9cuo@xmath10 the pg feature was seen in numerous experiments ( nmr , tunneling spectra , resistivity etc . ; see for example reviews @xcite ) . it has been stressed @xcite that the pg temperature is not defined unambiguously .

Suppose that you have an abstract for a scientific paper: we have performed a series of cosmic - ray electron observations using the balloon - borne emulsion chambers since 1968 . while we previously reported the results from subsets of the exposures , the final results of the total exposures up to 2001 are presented here . our successive experiments have yielded the total exposure of 8.19 m@xmath0 sr day at the altitudes of @xmath1 g @xmath2 . the performance of the emulsion chambers was examined by accelerator beam tests and monte - carlo simulations , and the on - board calibrations were carried out by using the flight data . in this work we present the cosmic - ray electron spectrum in the energy range from 30 gev to 3 tev at the top of the atmosphere , which is well represented by a power - law function with an index of @xmath3 . the observed data can be also interpreted in terms of diffusive propagation models . the evidence of cosmic - ray electrons up to 3 tev suggests the existence of cosmic - ray electron sources at distances within @xmath4 kpc and times within @xmath5 yr ago . . And you have already written the first three sentences of the full article: electrons in cosmic rays have unique features , complementary to the cosmic - ray nuclear components , because of their low mass and leptonic nature . high - energy electrons lose energy by synchrotron radiation in the galactic magnetic field and inverse compton scattering with the interstellar photons in the galaxy . high - energy cosmic - ray electrons can not propagate far from the sources , because the electrons lose rapidly energy with an energy loss rate of the square of energy through these radiative processes .. Please generate the next two sentences of the article

these processes during the propagations through the galaxy without hadronic interactions simplify modeling of the propagation of electrons compared with other cosmic - ray components such as nucleons . evidence for non - thermal x - ray emission from supernova remnants ( snrs ) indicate that high - energy electrons in the tev region are accelerated in snrs ( * ? ? ?

Suppose that you have an abstract for a scientific paper: we discuss the possibilities to observe the decays of heavy susy higgs bosons into supersymmetric particles at the lhc . such an observation would be of interest either in a discovery search if sparticle modes are the dominant ones , or in a study of additional decay modes , bringing information on the susy scenario potentially at work . we will focus on the most promising channel where the heavy neutral higgses decay into a pair of next - to - lightest neutralinos @xmath0 , followed by @xmath1 , thus leading to four isolated leptons + @xmath2 as the main final state signature . a study with the cms detector shows that the background ( sm + susy ) can be sufficiently suppressed and that in the mass region between @xmath3 @xmath4 230 and 450 gev , for low and intermediate values of @xmath5 , the signal would be visible provided neutralinos and sleptons are light enough . filip moortgat salavat abdullin daniel denegri . And you have already written the first three sentences of the full article: while the problem of electroweak symmetry breaking can be solved in the standard model ( sm ) by introducing one higgs boson , the minimal supersymmetric standard model ( mssm ) requires five physical higgses : a light cp - even ( @xmath6 ) , a heavy cp - even ( @xmath7 ) , a heavy cp - odd ( @xmath8 ) and two charged higgs bosons ( @xmath9 ) . therefore , the discovery of heavy neutral higgs bosons would be a major breakthrough in verifying the supersymmetric nature of the fundamental theory , which is one of the main physics goals of the large hadron collider project . + the most promising channel to discover the heavy susy higgses is the @xmath10 @xcite channel , where both the leptonic and hadronic decays of the tau can be exploited .. Please generate the next two sentences of the article

this channel has been shown to cover large parts of the intermediate and high @xmath11 region of the mssm parameter space for an integrated luminosity of 30 @xmath12 . for low values of @xmath11 , the coupling of the higgs bosons to taus is not sufficiently enhanced and therefore this region is inaccessible for the @xmath13 channel .

Suppose that you have an abstract for a scientific paper: theoretical quantum key distribution ( qkd ) protocols commonly rely on the use of qubits ( quantum bits ) . in reality , however , due to practical limitations , the legitimate users are forced to employ a larger quantum ( hilbert ) space , say a quhexit ( quantum six - dimensional ) space , or even a much larger quantum hilbert space . various specific attacks exploit of these limitations . although security can still be proved in some very special cases , a general framework that considers such realistic qkd protocols , _ as well as _ attacks on such protocols , is still missing . we describe a general method of attacking realistic qkd protocols , which we call the ` quantum - space attack ' . the description is based on assessing the enlarged quantum space actually used by a protocol , the ` quantum space of the protocol ' . we demonstrate these new methods by classifying various ( known ) recent attacks against several qkd schemes , and by analyzing a novel attack on interferometry - based qkd . . And you have already written the first three sentences of the full article: quantum cryptography has brought us new ways of exchanging a secret key between two users ( known as alice and bob ) . the security of such quantum key distribution ( qkd ) methods is based on a very basic rule of nature and quantum mechanics the `` no - cloning '' principle . the first qkd protocol was suggested in a seminal paper by bennett and brassard @xcite in 1984 , and is now known as bb84 . during recent years. Please generate the next two sentences of the article

many security analyses were published @xcite which proved the information - theoretical security of the bb84 scheme against the most general attack by an unlimited adversary ( known as eve ) , who has full control over the quantum channel . those security proofs are limited as they always consider a theoretical qkd that uses perfect qubits .

Suppose that you have an abstract for a scientific paper: a simple analytical framework to study the molecular quasispecies evolution of finite populations is proposed , in which the population is assumed to be a random combination of the constituent molecules in each generation , i.e. , linkage disequilibrium at the population level is neglected . in particular , for the single - sharp - peak replication landscape we investigate the dependence of the error threshold on the population size and find that the replication accuracy at the threshold increases linearly with the reciprocal of the population size for sufficiently large populations . furthermore , in the deterministic limit our formulation yields the exact steady - state of the quasispecies model , indicating then that the population composition is a random combination of the molecules . . And you have already written the first three sentences of the full article: an important issue in the investigation of the dynamics of competing self - reproducing macromolecules , whose paradigm is eigen s quasispecies model @xcite , is the effect of the finite size of the population on the error threshold phenomenon that limits the length of the molecules @xcite . the quasispecies model was originally formulated as a deterministic kinetic theory described by a set of ordinary differential equations for the concentrations of the different types of molecules that compose the population . such formulation , however , is valid only in the limit where the total number of molecules @xmath0 goes to infinity . more pointedly , in this model a molecule is represented by a string of @xmath1 digits @xmath2 , with the variables @xmath3 allowed to take on @xmath4 different values , each of which representing a different type of monomer used to build the molecule . for sake of simplicity ,. Please generate the next two sentences of the article

in this paper we will consider only binary strings , i.e. , @xmath5 . the concentrations @xmath6 of molecules of type @xmath7 evolve in time according to the following differential equations @xcite @xmath8 x_i \ ; , \ ] ] where the constants @xmath9 stand for the death probability of molecules of type @xmath10 , and @xmath11 is a dilution flux that keeps the total concentration constant .

Suppose that you have an abstract for a scientific paper: the supernova remnant n 157b contains a pulsar and three distinct synchrotron components with rather unusual properties . 1 ) a somewhat irregular elliptical pulsar wind nebula ( pwn ) visible in both x - ray and radio wavelengths . the nebula is quite symmetrical with an extent of about 10 @xmath0 5 parsecs but offset along the long axis by about 4 pc from the pulsar position . it is apparently the result of a short - lived injection of energetic particles , perhaps starting at the time of explosion . 2 ) a very bright x - ray shock region located just outside the pulsar position in the edge of the pwn . this is undetected in the radio . we attribute this to a new burst of particles from the pulsar suggesting there are multiple episodes rather than continuous injection . 3 ) the beginning of a radio synchrotron shell on the southern side of the snr where thermal x - rays appear to arise suggesting that n 157b is starting to become a composite snr . . And you have already written the first three sentences of the full article: n 157b ( henize , 1956 ) is a crab - type supernova remnant ( snr ) just 7 arcmin from the center of 30 doradus ( bode , 1801 ) in the large magellanic cloud ( lmc ) . it contains a 16-ms x - ray pulsar undetected at any other wavelength ( marshall et al . there is bright non - thermal x - ray emission with structure on arcsec scales just around the pulsar with an extended feature off to the northwest ( wang and gotthelf , 1998a , 1998b ; wang et al .. Please generate the next two sentences of the article

there is bright non - thermal radio emission from the extended feature but not at the pulsar location ( lazendic et al . we shall call the extended emission region the pulsar wind nebula ( pwn ) .

Suppose that you have an abstract for a scientific paper: based on the urqmd model , we have investigated the influence of the symmetry potential on the negatively and positively charged @xmath0 and @xmath1 hyperon production ratios in heavy ion collisions at the sis energies . we find that , in addition to @xmath2 ratio , the @xmath3 ratio can be taken as a sensitive probe for investigating the density dependence of the symmetry potential of nuclear matter at high densities ( 1 - 4 times of normal baryon density ) . this sensitivity of the symmetry potential to both the @xmath2 and @xmath3 ratios is found to depend strongly on the incident beam energy . furthermore , the @xmath3 ratio is shown to carry the information about the isospin - dependent part of the @xmath1 hyperon single - particle potential . . And you have already written the first three sentences of the full article: the equation of state ( eos ) has attracted a lot of attention recently for asymmetric nuclear matter , which can be described approximately by the parabolic law @xmath4 here @xmath5 is the isospin asymmetry , @xmath6 the energy per nucleon for symmetric nuclear matter , and @xmath7 the bulk symmetry energy . the symmetry energy term @xmath8 is very important for understanding many interesting astrophysical phenomena ( see , _ e.g. _ @xcite ) , but so far results in large uncertainties : _. Please generate the next two sentences of the article

e.g. _ , the symmetry energy calculated with different kinds of parameter sets ( skyrme or gogny type ) are largely divergent @xcite ) , especially at high densities , and for some cases , _ i.e. _ , when the density is higher than three times of the normal density , even a negative symmetry energy can be obtained . therefore , acquiring the more accurate knowledge of the symmetry energy , and the isospin asymmetry , becomes one of the main goals in nuclear physics at present .

Suppose that you have an abstract for a scientific paper: we study two different superconductor - ferromagnet ( s / f ) structures . we consider first a josephson junction which consists of two s / f bilayers separated by an insulating layer . we show that for an antiparallel alignment of the magnetization in the two f layers the josephson critical current @xmath0 increases with increasing exchange field @xmath1 . the second system we consider is a s / f structure with a local inhomogeneity of the magnetization in the ferromagnet near the s / f interface . due to the proximity effect not only a singlet but also a triplet component of the superconducting condensate is induced in the ferromagnet . the latter penetrates over the length @xmath2 ( @xmath3 is the diffusion coefficient and @xmath4 the energy ) . in the case of temperatures of the order of the thouless energy this length is comparable to the length of the ferromagnet . this long - range penetration leads to a significant increase of the ferromagnet conductance below the superconducting critical temperature @xmath5 . contrary to the case of the singlet component , the contribution to the conductance due to the odd triplet component is not zero at @xmath6 and @xmath7 ( @xmath8 is the voltage ) and decays with increasing temperature t in a monotonic way . pacs numbers : 74.80.dm , 74.25.fy , 74.50.+r . keywords : proximity effect , josephson effect , triplet superconductivity , ferromagnetism . . And you have already written the first three sentences of the full article: the interplay between superconductivity and ferromagnetism has been the subject of extensive research for many years . the ferromagnetism , being usually much stronger than superconductivity , is supposed to destroy the latter . this suppression is caused by two mechanisms .. Please generate the next two sentences of the article

one of them is related to the internal magnetic field which is created by the ordered magnetic moments . the internal magnetic field , which is proportional to the magnetization @xmath9 , induces meissner currents and suppresses the superconducting order parameter @xmath10 .

Suppose that you have an abstract for a scientific paper: we calculated the contribution of coulomb energy to the spacing between the ground and first excited state of @xmath0th nucleus as a function of the deformation parameter @xmath1 . we show that despite the fact that the odd particle is a neutron , the change in coulomb energy @xmath2 between these two states can reach several hundreds kev . this means that the effect of the variation of the fine structure constant @xmath3 may be enhanced @xmath4 times in the @xmath57.6 ev `` nuclear clock '' transition between the ground and first excited states in the @xmath0th nucleus . . And you have already written the first three sentences of the full article: unification theories applied to cosmology suggest a possibility of variation of the fundamental constants in the expanding universe ( see e.g. review @xcite ) . there are hints of variation of @xmath6 and @xmath7 in quasar absorption spectra , big bang nucleosynthesis and oklo natural nuclear reactor data ( see @xcite and references therein ) . here @xmath8 is the quantum chromodynamics ( qcd ) scale , and @xmath9 and @xmath10 are the quark and electron masses . however , the majority of publications report only limits on possible variations ( see e.g. @xcite ) . a very sensitive method to study the variation in a laboratory. Please generate the next two sentences of the article

consists of the comparison of different optical and microwave atomic clocks ( see e.g. measurements in @xcite ) . an enhancement of the relative effect of @xmath6 variation can be obtained in a transition between almost degenerate levels in dy atom @xcite .

Suppose that you have an abstract for a scientific paper: this article reviews some of the leading results obtained in solar dynamo physics by using temporal oscillator models as a tool to interpret observational data and dynamo model predictions . we discuss how solar observational data such as the sunspot number is used to infer the leading quantities responsible for the solar variability during the last few centuries . moreover , we discuss the advantages and difficulties of using inversion methods ( or backward methods ) over forward methods to interpret the solar dynamo data . we argue that this approach could help us to have a better insight about the leading physical processes responsible for solar dynamo , in a similar manner as helioseismology has helped to achieve a better insight on the thermodynamic structure and flow dynamics in the sun s interior . . And you have already written the first three sentences of the full article: the number of dark spots in the sun s surface has been counted in a systematic way since rudolf wolf introduced the concept , in the first half of the nineteenth century . more than any other solar observable , the sunspot number is considered the strongest signature of the 22-year magnetic cycle . moreover , since the sunspot number is the longest time series from all solar observables @xcite , it makes it the preferred proxy to study the variability and irregularity of the solar magnetic cycle . in the sun s interior the large scale magnetic field is generated by a magnetohydrodynamic dynamo that converts part of the kinetic energy of the plasma motions into magnetic energy .. Please generate the next two sentences of the article

polarity reversals occur every 11 years approximately , as it can be observed directly in the sun s dipolar field , and taking a full 22-years to complete a magnetic cycle . in fact during each magnetic cycle , the sun experiences two periods of maximum magnetic activity , during which magnetic flux tubes created in the tachocline layer , rise to the sun s surface by the action of buoyancy , emerging as sunspots pairs @xcite .

Suppose that you have an abstract for a scientific paper: recent investigations have shown that the extended main - sequence turnoffs ( emstos ) are a common feature of intermediate - age star clusters in the magellanic clouds . the emstos are also found in the color - magnitude diagram ( cmd ) of young - age star clusters . the origin of the emstos is still an open question . moreover , asteroseismology shows that the value of the overshooting parameter @xmath0 of the convective core is not fixed for the stars with an approximatelly equal mass . thus the msto of star clusters may be affected by the overshooting of the convective core ( ovcc ) . we calculated the effects of the ovcc with different @xmath0 on the msto of young- and intermediate - age star clusters . * if @xmath0 varies between stars in a cluster , * the observed emstos of young- and intermediate - age star clusters can be explained well by the effects . the equivalent age spreads of msto caused by the ovcc are related to the age of star clusters and are in good agreement with observed results of many clusters . moreover , the observed emstos of ngc 1856 are reproduced by the coeval populations with different @xmath0 . the emstos of star clusters may be relevant to the effects of the ovcc . the effects of the ovcc * are similar to that of rotation in some respects . but the effects can not result in a significant split of main sequence of young star clusters at @xmath1 . * the presence of a rapid rotation can make the split of main sequence of young star clusters more significant . . And you have already written the first three sentences of the full article: the double or extended main - sequence turnoffs ( emstos ) were discovered in the color - magnitude diagram ( cmd ) of intermediate - age massive star clusters in the magellanic clouds @xcite . one interpretation of the emstos is that the clusters have experienced an extended star - formation histories ( esfh ) with a duration of @xmath2 myr @xcite , which disagrees with classical understanding of star clusters being simple stellar populations ( ssps ) . the emstos were also discovered in young clusters ngc 1856 @xcite , ngc 1755 @xcite , ngc 1850 @xcite , and ngc 1866 @xcite .. Please generate the next two sentences of the article

moreover , ngc 1856 , ngc 1755 , and ngc 1866 are found to exhibit dual main sequences ( ms ) below their msto @xcite . an alternative interpretation of the emstos is the effects of star rotation @xcite .

Suppose that you have an abstract for a scientific paper: we consider two different toy cosmological models based on two fields ( one normal scalar and one phantom ) realizing the same evolution of the bang - to - rip type . one of the fields ( pseudoscalar ) interacts with the magnetic field breaking the conformal invariance of the latter . the effects of the amplification of cosmic magnetic fields are studied and it is shown that the presence of such effects can discriminate between different cosmological models realizing the same global evolution of the universe . _ keywords _ : phantom dark energy , scalar fields , magnetic fields + . And you have already written the first three sentences of the full article: the discovery of the cosmic acceleration @xcite and the search for dark energy responsible for its origin @xcite have stimulated the study of different field models driving the cosmological evolution . such a study usually is called the potential reconstruction @xcite , because the most typical examples of these models are those with a scalar field , whose potential should be found to provide a given dynamics of the universe . in the flat friedmann models with a single scalar field , the form of the potential and the time dependence of the scalar field are uniquely determined by the evolution of the hubble variable ( up to a shift of the scalar field ) . during last years. Please generate the next two sentences of the article

the models with two scalar fields have also become very popular . this is connected with the fact that some observations point out that the relation between the pressure and the energy density could be less than -1 @xcite .

Suppose that you have an abstract for a scientific paper: in a survey of quasar candidates selected by matching the first and 2mass catalogs , we have found two extraordinarily red quasars . first j013435.7@xmath0093102 is a 1 jy source at @xmath1 and has @xmath2 , while first j073820.1 + 275045 is a 2.5 mjy source at z=1.985 with @xmath3 . first j073820.1 + 275045 has strong absorption lines of and in the rest frame of the quasar and is highly polarized in the rest frame ultraviolet , strongly favoring the interpretation that its red spectral energy distribution is caused by dust reddening local to the quasar . first j073820.1 + 275045 is thus one of the few low radio - luminosity , highly dust - reddened quasars known . the available observational evidence for first j013435.7@xmath0093102 leads us to conclude that it too is reddened by dust . we show that first j013435.7@xmath0093102 is gravitationally lensed , increasing the number of known lensed , extremely dust - reddened quasars to at least three , including mg0414@xmath00534 and pks1830@xmath0211 . we discuss the implications of whether these objects are reddened by dust in the host or lensing galaxies . if reddened by their local environment , then we estimate that between 10 and 20% of the radio - loud quasar population is reddened by dust in the host galaxy . the discovery of first j073820.1 + 275045 and objects now emerging from x - ray surveys suggests the existence of an analogous radio - quiet red quasar population . such objects will be entirely missed by standard radio or optical quasar surveys . if dust in the lensing galaxies is primarily responsible for the extreme redness of the lensed quasars , then an untold number of gravitationally lensed quasars are being overlooked . . And you have already written the first three sentences of the full article: the vast majority of the @xmath4 catalogued quasars have very similar optical spectral energy distributions : a very blue continuum with prominent broad emission lines . several studies provide evidence that a population of _ red _ quasars also exists , overlooked by surveys optimized to find quasars by their uv excess and strong emission lines . the size of any such `` hidden '' population of quasars is important for a complete understanding of the quasar phenomenon .. Please generate the next two sentences of the article

low et al . ( 1989 ) found that the majority of quasars in a small ir - selected sample were significantly redder than optically selected objects . sprayberry & foltz ( 1992 ) argue that the larger dust extinction and very weak emission features in low ionization broad absorption line ( bal ) quasars means that they are underrepresented in the known quasar population . using a much larger sample , webster et al .

Suppose that you have an abstract for a scientific paper: we apply the weak field approximation limit of the covariant scalar - tensor - vector gravity ( stvg ) theory , so - called modified gravity ( mog ) , to the dynamics of clusters of galaxies by using only baryonic matter . the mog effective gravitational potential in the weak field approximation is composed of an attractive newtonian term and a repulsive yukawa term with two parameters @xmath0 and @xmath1 . the numerical values of these parameters have been obtained by fitting the predicted rotation curves of galaxies to observational data , yielding the best fit result : @xmath2 and @xmath3 kpc@xmath4 @xcite . we extend the observational test of this theory to clusters of galaxies , using data for the ionized gas and the temperature profile of nearby clusters obtained by the chandra x - ray telescope . using the mog virial theorem for clusters , we compare the mass profiles of clusters from observation and theory for eleven clusters . the theoretical mass profiles for the inner parts of clusters exceed the observational data . however , the observational data for the inner parts of clusters ( i.e. , @xmath5 ) is scattered , but at distances larger than @xmath6 kpc , the observed and predicted mass profiles converge . our results indicate that mog as a theory of modified gravity is compatible with the observational data from the the solar system to mega parsec scales without invoking dark matter . . And you have already written the first three sentences of the full article: zwicky showed that there is an inconsistency between the dynamical mass and the luminous mass for the coma cluster . he postulated that there must exist dark matter at the scale of clusters of galaxies @xcite . the observations of the rotation curves of spiral galaxies by rubin also indicated that galaxies need missing mass in the context of newtonian gravity @xcite .. Please generate the next two sentences of the article

the main paradigm to interpret missing mass in the universe is the theory of dark matter , supposing that the unseen matter accounts for more than @xmath7 of the universe s matter content . this hypothetical matter is made of particles ( e.g.,wimps ) that may only interact weakly with ordinary baryonic matter .

Suppose that you have an abstract for a scientific paper: semilocal and electroweak strings are well - known to be unstable against unwinding by the condensation of the second higgs component in their cores . a large class of current models of dark matter contains dark scalar fields coupled to the higgs sector of the standard model ( higgs portal ) and/or dark u(1 ) gauge fields . it is shown , that higgs - portal - type couplings and a gauge kinetic mixing term of the dark u(1 ) gauge field have a significant stabilising effect on semilocal strings in the `` visible '' sector . cosmic strings and their observational signatures have been studied since a long time as they are expected to form in the early universe @xcite . even if by now it seems unlikely that cosmic strings could have significantly contributed to structure formation in the universe , string - like excitations in the standard model ( sm ) continue to be of great interest not only from a theoretical point of view , but such objects may eventually leave observable signatures , e.g. , in the large hadron collider @xcite . remarkable string solutions have been uncovered in the bosonic sector of the glashow - salam - weinberg ( gsw ) theory ( in this paper we shall refer to a generalisation of the electroweak sector of the sm allowing its parameters to take on non - physical values as the gsw theory . ) , for a review see ref . @xcite . a rather interesting class of models emerges by taking the @xmath0 limit of the gsw theory , where @xmath1 denotes the electroweak mixing angle . one obtains this way an abelian higgs model with an extended scalar sector having an @xmath2 symmetry acting on the higgs doublet , this a a prototype of semilocal models . its strings solutions are referred to as semilocal strings @xcite and these are quite instructive to study as being potentially important object in the gsw theory . an important criterion for the physical relevance of string - type objects is their classical stability . semilocal strings turned out to be stable only when the mass of.... And you have already written the first three sentences of the full article: in refs . @xcite , a unified model of dark matter has been presented , which posits a ds with a u(1 ) gauge symmetry , spontaneously broken in order to avoid long range interactions . the ds is modelled by an ah model @xmath5 , where the dark scalar field , @xmath6 , couples to the gsw theory through a higgs portal coupling @xcite and the dark gauge field @xmath7 through a gauge kinetic mixing term @xcite .. Please generate the next two sentences of the article

we consider the following semilocal model coupled to a ds defined by the lagrangian . ] : @xmath8 where @xmath9 , @xmath10 , @xmath11 , @xmath12 , @xmath13 . the potential , @xmath14 is a slight generalisation of that of the witten model @xcite , @xmath15 the parameters @xmath16 , @xmath17 , @xmath18 , @xmath19 are restricted by demanding that @xmath20 for @xmath21 , resulting in : @xmath22 , @xmath23 , and @xmath24 . for a description of the vacua of @xmath14 we refer to refs .

Suppose that you have an abstract for a scientific paper: we show , in the context of quantum combinatorial optimization , or quantum annealing , how the nonlinear schrdinger - langevin - kostin equation can dynamically drive the system toward its ground state . we illustrate , moreover , how a frictional force of kostin type can prevent the appearance of genuinely quantum problems such as bloch oscillations and anderson localization which would hinder an exhaustive search . . And you have already written the first three sentences of the full article: the aim of combinatorial optimization is to find good approximations to the solution(s ) of minimization problems . many of the most famous algorithms currently used in this field @xcite were inspired by analogies with physical systems . among them the most celebrated is _ thermal simulated annealing _ @xcite proposed in 1983 by kirkpatrick _. Please generate the next two sentences of the article

et al . _ : the space of all admissible solutions is endowed with a potential profile dependent on the cost function associated to the optimization problem . the exploration of this space is represented by a temperature dependent random walk .

Suppose that you have an abstract for a scientific paper: the action of a channel on a quantum system , when non trivial , always causes deterioration of initial quantum resources , understood as the entanglement initially shared by the input system with some reference purifying it . one effective way to measure such a deterioration is by measuring the loss of coherent information , namely the difference between the initial coherent information and the final one : such a difference is `` small '' , if and only if the action of the channel can be `` almost perfectly '' corrected with probability one . in this work , we generalise this result to different entanglement loss functions , notably including the entanglement of formation loss , and prove that many inequivalent entanglement measures lead to equivalent conditions for approximate quantum error correction . in doing this , we show how different measures of bipartite entanglement give rise to corresponding distance - like functions between quantum channels , and we investigate how these induced distances are related to the cb - norm . . And you have already written the first three sentences of the full article: what is irreversibility of a process ? this question , in this form , does not make much sense . we first have to specify `` irreversibility with respect to what '' .. Please generate the next two sentences of the article

it means we first need to decide a set of rules e. a set of allowed transformations together with some free resource to which one has to conform when trying to revert the process .

Suppose that you have an abstract for a scientific paper: in previous works , we showed that the internal dla cluster on @xmath0 with @xmath1 particles is almost surely spherical up to a maximal error of @xmath2 if @xmath3 and @xmath4 if @xmath5 . this paper addresses `` average error '' : in a certain sense , the average deviation of internal dla from its mean shape is of _ constant _ order when @xmath3 and of order @xmath6 ( for a radius @xmath7 cluster ) in general . appropriately normalized , the fluctuations ( taken over time and space ) scale to a variant of the gaussian free field . . And you have already written the first three sentences of the full article: we study scaling limits of _ internal diffusion limited aggregation _ ( `` internal dla '' ) , a growth model introduced in @xcite . in internal dla , one inductively constructs an * occupied set * @xmath8 for each time @xmath9 as follows : begin with @xmath10 and @xmath11 , and let @xmath12 be the union of @xmath13 and the first place a random walk from the origin hits @xmath14 . the purpose of this paper is to study the growing family of sets @xmath13 . following the pioneering work of @xcite , it is by now well known that , for large @xmath1 , the set @xmath13 approximates an origin - centered euclidean lattice ball @xmath15 ( where @xmath16 is such that @xmath17 has volume @xmath1 ) .. Please generate the next two sentences of the article

the authors recently showed that this is true in a fairly strong sense @xcite : the maximal distance from a point where @xmath18 is non - zero to @xmath19 is a.s . @xmath2 if @xmath3 and @xmath4 if @xmath5 .