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Suppose that you have an abstract for a scientific paper: a star formation efficiency per free fall time that evolves over the life time of giant molecular clouds ( gmcs ) may have important implications for models of supersonic turbulence in molecular clouds or for the relation between star formation rate and @xmath0 surface density . we discuss observational data that could be interpreted as evidence of such a time variability . in particular , we investigate a recent claim based on measurements of @xmath0 and stellar masses in individual gmcs . we show that this claim depends crucially on the assumption that @xmath0 masses do not evolve over the life times of gmcs . we exemplify our findings with a simple toy model that uses a constant star formation efficiency and , yet , is able to explain the observational data . . And you have already written the first three sentences of the full article: the life times of giant molecular clouds ( gmcs ) have been at the center of a major debate for at least the last 40 years @xcite . gmcs that live for many free - fall times need a mechanism that prevents them from gravitational collapse . over the last couple of years the consensus is growing that the life times of gmcs are likely a few free - fall times , or even less @xcite and the focus has shifted towards the challenge of explaining the low star formation efficiencies in gmcs .. Please generate the next two sentences of the article
the star formation efficiency per free fall time @xmath1 is defined as the ratio of free fall time @xmath2 to gas depletion time @xmath3 . in other words : @xmath4 i.e. the instantaneous star formation rate ( sfr ) is proportional to the available amount of molecular hydrogen ( @xmath0 ) via the proportionality factor @xmath5 .
10,801
Suppose that you have an abstract for a scientific paper: pure spin currents in semiconductors are essential for implementation in the next generation of spintronic elements . heterostructures of iii- nitride semiconductors are currently employed as central building - blocks for lighting and high - power devices . moreover , the long relaxation times and the spin - orbit coupling ( soc ) in these materials indicate them as privileged hosts for spin currents and related phenomena . spin pumping is an efficient mechanism for the inception of spin current and its conversion into charge current in non - magnetic metals and semiconductors with rashba soc @xmath0 spin hall effects . we report on the generation in @xmath1-gan : si at room temperature and through spin pumping of pure spin current , fundamental for the understanding of the spin dynamics in these non - centrosymmetric rashba systems . we find for @xmath1-gan : si a spin hall angle @xmath2=@xmath3 , exceeding by one order of magnitude those reported for other semiconductors , pointing at iii - nitrides as particularly efficient spin current generators . in the emerging field of spin - orbitronics @xcite spin - orbit coupling ( soc ) is employed in both magnetic and non - magnetic materials to generate , exploit and detect spin currents . spin currents hold the key for the realization and implementation of the next generation of spin based nanoelectronic devices with properties like non - volatility , low power consumption and dissipation . while in magnetic materials the soc is employed to create new classes of topological objects like magnetic skyrmions or dzyalonshinskii - moriya domain walls @xcite , spin - orbitronics in non - magnetic materials mostly addresses the spin - to - charge conversion through the spin hall effect ( she ) @xcite and the rashba - edelstein effect @xcite . the concept of she is borrowed from the anomalous hall effect ( ahe ) where , due to the relativistic soc , asymmetric deflection of charge carriers takes place depending on their spin orientations @xcite.... And you have already written the first three sentences of the full article: the experiments have been performed on a 1.9 @xmath35 thick degenerately doped @xmath1-gan : si film with electron concentration ( @xmath3610@xmath37)@xmath38 and carrier mobility , @xmath39 , grown by metal organic vapour phase epitaxy ( movpe ) on @xmath40-@xmath41 . a 10 nm permalloy ( py = @xmath42 ) film is used as fm layer and source of spins . the py film is passivated with a 6 nm @xmath43 film which protects the fm from oxidation in order to avoid the detrimental effects of oxidised py on the spin pumping efficiency @xcite .. Please generate the next two sentences of the article
the py/@xmath1-gan : si bilayer is driven to resonance conditions at room temperature under an x - band microwave excitation of ( @xmath44 ) ghz with an external magnetic field in a bruker elexsys e580 electron paramagnetic resonance spectrometer . the permalloy being a soft fm has a small magnetocrystalline anisotropy , so that @xmath23 in py is aligned along the film plane when an in - plane magnetic field @xmath20 is applied . ohmic contacts to @xmath1-gan : si are fabricated by e - beam evaporation of ti / au / al / ti / au as a metallic stack . the quartz sample holder for the fmr measurements is provided with two high conducting copper wires and connected to a keithley 2700 dmm for measuring the generated dc voltage .
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Suppose that you have an abstract for a scientific paper: high - contrast adaptive optics imaging is a powerful technique to probe the architectures of planetary systems from the outside - in and survey the atmospheres of self - luminous giant planets . direct imaging has rapidly matured over the past decade and especially the last few years with the advent of high - order adaptive optics systems , dedicated planet - finding instruments with specialized coronagraphs , and innovative observing and post - processing strategies to suppress speckle noise . this review summarizes recent progress in high - contrast imaging with particular emphasis on observational results , discoveries near and below the deuterium - burning limit , and a practical overview of large - scale surveys and dedicated instruments . i conclude with a statistical meta - analysis of deep imaging surveys in the literature . based on observations of 384 unique and single young ( @xmath05300 myr ) stars spanning stellar masses between 0.13.0 , the overall occurrence rate of 513 companions at orbital distances of 30300 au is 0.6@xmath1% assuming hot - start evolutionary models . the most massive giant planets regularly accessible to direct imaging are about as rare as hot jupiters are around sun - like stars . dividing this sample into individual stellar mass bins does not reveal any statistically - significant trend in planet frequency with host mass : giant planets are found around 2.8@xmath2% of ba stars , @xmath34.1% of fgk stars , and @xmath33.9% of m dwarfs . looking forward , extreme adaptive optics systems and the next generation of ground- and space - based telescopes with smaller inner working angles and deeper detection limits will increase the pace of discovery to ultimately map the demographics , composition , evolution , and origin of planets spanning a broad range of masses and ages . . And you have already written the first three sentences of the full article: [ sec : intro ] over the past two decades the orbital architecture of giant planets has expanded from a single order of magnitude in the solar system ( 530 au ) to over five orders of magnitude among extrasolar planetary systems ( 0.015000 au ; figure [ fig : mass_sma ] ) . high - contrast adaptive optics ( ao ) imaging has played a critical role in this advancement by probing separations beyond @xmath410 au and masses @xmath51 . uncovering planetary - mass objects at hundreds and thousands of au has fueled novel theories of planet formation and migration , inspiring a more complex framework for the origin of giant planets in which multiple mechanisms ( core accretion , dynamical scattering , disk instability , and cloud fragmentation ) operate on different timescales and orbital separations .. Please generate the next two sentences of the article
in addition to probing unexplored orbital distances , imaging entails directly capturing photons that originated in planetary atmospheres , providing unparalleled information about the initial conditions , chemical composition , internal structure , atmospheric dynamics , photospheric condensates , and physical properties of extrasolar planets . these three science goals the architecture , formation , and atmospheres of gas giants represent the main motivations to directly image and spectroscopically characterize extrasolar giant planets .
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Suppose that you have an abstract for a scientific paper: we develop a representation suitable for the unconstrained recognition of words in natural images , where unconstrained means that there is no fixed lexicon and words have unknown length . to this end we propose a convolutional neural network ( cnn ) based architecture which incorporates a conditional random field ( crf ) graphical model , taking the whole word image as a single input . the unaries of the crf are provided by a cnn that predicts characters at each position of the output , while higher order terms are provided by another cnn that detects the presence of n - grams . we show that this entire model ( crf , character predictor , n - gram predictor ) can be jointly optimised by back - propagating the structured output loss , essentially requiring the system to perform multi - task learning , and training requires only synthetically generated data . the resulting model is a more accurate system on standard real - world text recognition benchmarks than character prediction alone , setting a benchmark for systems that have not been trained on a particular lexicon . in addition , our model achieves state - of - the - art accuracy in lexicon - constrained scenarios , without being specifically modelled for constrained recognition . to test the generalisation of our model , we also perform experiments with random alpha - numeric strings to evaluate the method when no visual language model is applicable . . And you have already written the first three sentences of the full article: in this work we tackle the problem of _ unconstrained text recognition _ recognising text in natural images without restricting the words to a fixed lexicon or dictionary . usually this problem is decomposed into a word detection stage followed by a word recognition stage . the word detection stage generates bounding boxes around words in an image , while the word recognition stage takes the content of these bounding boxes and recognises the text within .. Please generate the next two sentences of the article
this paper focuses on the text recognition stage , developing a model based on deep convolutional neural networks ( cnns ) ( @xcite ) . previous methods using cnns for word recognition ( discussed in more detail in section section [ sec : related ] ) has either constrained ( @xcite ) or heavily weighted ( @xcite ) the recognition results to be from a dictionary of known words .
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Suppose that you have an abstract for a scientific paper: we use high spatial resolution observations of co to systematically measure the resolved _ size - line width _ , _ luminosity - line width _ , _ luminosity - size _ , and the _ mass - luminosity _ relations of giant molecular clouds ( gmcs ) in a variety of extragalactic systems . although the data are heterogeneous we analyze them in a consistent manner to remove the biases introduced by limited sensitivity and resolution , thus obtaining reliable sizes , velocity dispersions , and luminosities . we compare the results obtained in dwarf galaxies with those from the local group spiral galaxies . we find that extragalactic gmc properties measured across a wide range of environments are very much compatible with those in the galaxy . the property that shows the largest variability is their resolved brightness temperature , although even that is similar to the average galactic value in most sources . we use these results to investigate metallicity trends in the cloud average column density and virial co - to - h@xmath0 factor . we find that these measurements do not accord with simple predictions from photoionization - regulated star formation theory , although this could be due to the fact that we do not sample small enough spatial scales or the full gravitational potential of the molecular cloud . we also find that the virial co - to - h@xmath0 conversion factor in co - bright gmcs is very similar to galactic , and that the excursions do not show a measurable metallicity trend . we contrast these results with estimates of molecular mass based on far - infrared measurements obtained for the small magellanic cloud , which systematically yield larger masses , and interpret this discrepancy as arising from large h@xmath0 envelopes that surround the co - bright cores . we conclude that gmcs identified on the basis of their co emission are a unique class of object that exhibit a remarkably uniform set of properties from galaxy to galaxy . . And you have already written the first three sentences of the full article: giant molecular clouds ( gmcs ) are the major reservoirs of molecular gas and the sites of most star formation in our galaxy and other galaxies . their properties set the initial conditions for protostellar collapse , and may play a role in determining the stellar initial mass function @xcite . moreover , because gmcs provide the bulk of the material for forming new stars their creation may be the limiting mechanism that regulates the rate of star formation in galaxies . therefore. Please generate the next two sentences of the article
, increasing our understanding of their properties and distribution throughout the different environments of external galaxies is likely to provide further insights into gmc and stellar formation processes . there is a limited amount of information , however , that can be gained from studies that resolve the general distribution of molecular gas but not the individual molecular clouds . resolving gmcs to measure their sizes , velocity dispersions , and luminosities is a critical step in understanding the processes that ultimately drive galaxy evolution .
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Suppose that you have an abstract for a scientific paper: we study single - spin asymmetries in semi - inclusive deep inelastic scattering with transversely polarized target . based on the qcd factorization approach , we consider sivers and collins contributions to the asymmetries . we fit simple parameterizations for the sivers and collins functions to the recent hermes data , and compare to results from compass . using the fitted parameterizations for the sivers functions , we predict the single transverse spin asymmetries for various processes in @xmath0 collisions at rhic , including the drell - yan process and angular correlations in di - jet and jet - plus - photon production . these asymmetries are found to be sizable at forward rapidities . . And you have already written the first three sentences of the full article: single - transverse spin asymmetries ( ssa ) in hadronic processes have a long history , starting from the 1970s and 1980s when surprisingly large ssas were observed in @xmath1 @xcite and @xmath2 @xcite at forward rapidities of the produced hadron . they have again attracted much interest in recent years from both experimental and theoretical sides @xcite . in particular , first measurements by the star , phenix , and brahms collaborations at rhic have now become available @xcite , which extend the ssa observations from the fixed - target energy range to the collider regime . again. Please generate the next two sentences of the article
, large asymmetries were found in @xmath3 at forward rapidities of the produced pion . meanwhile , experimental studies in deep inelastic scattering ( dis ) by the hermes collaboration at desy , by smc at cern , and by clas at the jefferson laboratory also show remarkably large ssas in semi - inclusive hadron production , @xmath4 @xcite .
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Suppose that you have an abstract for a scientific paper: we consider the minimal energy problem on the unit sphere @xmath0 in the euclidean space @xmath1 in the presence of an external field @xmath2 , where the energy arises from the riesz potential @xmath3 ( where @xmath4 is the euclidean distance and @xmath5 is the riesz parameter ) or the logarithmic potential @xmath6 . characterization theorems of frostman - type for the associated extremal measure , previously obtained by the last two authors , are extended to the range @xmath7 the proof uses a maximum principle for measures supported on @xmath0 . when @xmath2 is the riesz @xmath5-potential of a signed measure and @xmath8 , our results lead to explicit point - separation estimates for @xmath9-fekete points , which are @xmath10-point configurations minimizing the riesz @xmath5-energy on @xmath0 with external field @xmath2 . in the hyper - singular case @xmath11 , the short - range pair - interaction enforces well - separation even in the presence of more general external fields . as a further application , we determine the extremal and signed equilibria when the external field is due to a negative point charge outside a positively charged isolated sphere . moreover , we provide a rigorous analysis of the three point external field problem and numerical results for the four point problem . . And you have already written the first three sentences of the full article: let @xmath12 be the unit sphere in @xmath1 , where @xmath13 denotes the euclidean norm . given a compact set @xmath14 , consider the class @xmath15 of unit positive borel measures supported on @xmath16 . for @xmath17 the _ riesz @xmath5-potential _ and _ riesz @xmath5-energy _ of a measure @xmath18 are given , respectively , by @xmath19 where @xmath20 is the so - called _. Please generate the next two sentences of the article
riesz kernel_. the _ @xmath5-capacity _ of @xmath16 is then defined as @xmath21 for @xmath17 , where @xmath22 is the _ @xmath5-energy _ of the set @xmath16 . a property is said to hold _ quasi - everywhere _
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Suppose that you have an abstract for a scientific paper: the full spectrum of two - dimensional fermion states in a scalar soliton trap with a lorentz breaking background is investigated in the context of the novel 2d materials , where the lorentz symmetry should not be strictly valid . the field theoretical model with lorentz breaking terms represents dirac electrons in one valley and in a scalar field background . the lorentz violation comes from the difference between the dirac electron and scalar mode velocities , which should be expected when modelling the electronic and lattice excitations in 2d materials . we extend the analytical methods developed in the context of 1 + 1 field theories to explore the effect of the lorentz symmetry breaking in the charge carrier density of 2d materials in the presence of a domain wall with a kink profile . the width and the depth of the trapping potential from the kink is controlled by the lorentz violating term , which is reflected analytically in the band structure and properties of the trapped states . our findings enlarge previous studies of the edge states obtained with domain wall and in strained graphene nanoribbon in a chiral gauge theory . . And you have already written the first three sentences of the full article: since the seminal work by skyrme @xcite , where the first three - dimensional topological defect solution arising from a nonlinear field theory was presented in the context of particle physics , a very large number of studies reporting the impact of some kind of topological defect has appeared in the physics literature and , in recent years , this area of research remains one the most active fields in many areas of the physics , including condensed matter physics @xcite , field theory topological - ft , and cosmology @xcite . for instance , in an astrophysical scenario , topological defects arises largely from grand unified theories ( guts ) of elementary particles . in this case , it is expected that the known local gauge symmetry group @xmath0 resulted from an underlying symmetry group @xmath1after a series of spontaneous symmetry breakings .. Please generate the next two sentences of the article
thus , the early universe has gone through a number of phase transitions , with one or more several types of topological defects possibly being left behind . another interesting background , where we can find topological configurations , is high energy physics @xcite . in this context
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Suppose that you have an abstract for a scientific paper: penetrating gamma - rays require complex instrumentation for astronomical spectroscopy measurements of gamma - rays from cosmic sources . multiple - interaction detectors in space combined with sophisticated post - processing of detector events on ground have lead to a spectroscopy performance which is now capable to provide new astrophysical insights . spectral signatures in the mev regime originate from transitions in the nuclei of atoms ( rather than in their electron shell ) . nuclear transitions are stimulated by either radioactive decays or high - energy nuclear collisions such as with cosmic rays . gamma - ray lines have been detected from radioactive isotopes produced in nuclear burning inside stars and supernovae , and from energetic - particle interactions in solar flares . radioactive - decay gamma - rays from @xmath0ni directly reflect the source of supernova light . @xmath1ti is produced in core - collapse supernova interiors , and the paucity of corresponding @xmath1ti gamma - ray line sources reflects the variety of dynamical conditions herein . @xmath2al and @xmath3fe are dispersed in interstellar space from massive - star nucleosynthesis over millions of years . gamma - rays from their decay are measured in detail by gamma - ray telescopes , astrophysical interpretations reach from massive - star interiors to dynamical processes in the interstellar medium . nuclear de - excitation gamma - ray lines have been found in solar - flare events , and convey information about energetic - particle production in these events , and their interaction in the solar atmosphere . the annihilation of positrons leads to another type of cosmic gamma - ray source . the characteristic annihilation gamma - rays at 511 kev have been measured long ago in solar flares , and now throughout the interstellar medium of our milky way galaxy . but now a puzzle has appeared , as a surprising predominance of the central bulge region was determined . this requires either new positron sources or.... And you have already written the first three sentences of the full article: the characteristic energies of gamma - rays are measured in _ _ energy units of mev__ev ) , corresponds to a wavelength of about 10@xmath4 m or a frequency of 10@xmath5hz . ] , 56 orders of magnitude above the typical energies of atomic transitions which shape spectra in the optical domain . cosmic gamma - rays thus are messengers of high - energy processes in cosmic sites . the typical binding energy of electrons in atoms are several ev , while binding energies of nucleons in atomic nuclei are of order several mev ; hence , mev gamma - rays are often related to _ nuclear transitions_. characteristic temperatures for gamma - ray emission , according to wien s displacement law , would be 10@xmath6k ( = gk ) for thermal gamma - rays ; at such temperatures , objects would be unstable unless confined , e.g. the interior of a star may be at temperatures of millions of k as the large gravitational mass holds the object together , while nova and supernova explosions feature gk temperatures in their interiors .. Please generate the next two sentences of the article
mev energies are above the rest mass energy of electrons , hence electrons and positrons at these are _ relativistic_. = 6 is the subject of the current paper .
10,809
Suppose that you have an abstract for a scientific paper: spin dependent transport in a multi - terminal mesoscopic ring is investigated in presence of rashba and dresselhaus spin - orbit interactions . within a tight - binding framework we use a general spin density matrix formalism to evaluate all three components ( @xmath0 , @xmath1 and @xmath2 ) of the polarization vector associated with the charge current through the outgoing leads . it explores the dynamics of the spin polarization vector of current propagating through the system subjected to the rashba and/or the dresselhaus spin - orbit couplings . the sensitivity of the polarization components on the electrode - ring interface geometry is discussed in detail . our present analysis provides an understanding of the coupled spin and electron transport in mesoscopic bridge systems . . And you have already written the first three sentences of the full article: one of the major goals of spintronic applications has always been to manipulate electron s spin degree of freedom to create a new paradigm @xcite in the fields of quantum information processing . spin-@xmath3 particles are a natural choice for a qubit in quantum computers . so , generation of spin polarized beam is a highly significant issue as far as spintronic applications are concerned . a more or less usual way of realization @xcite of spin filtering action is by using ferromagnetic leads or by external magnetic field .. Please generate the next two sentences of the article
but , in the first case , spin injection from ferromagnetic lead is difficult due to large resistivity mismatch and for the second one , the difficulty is to confine a very strong magnetic field into a small region like a quantum ring . therefore , attention is being paid for modeling of spin filter using the intrinsic properties of mesoscopic systems such as spin - orbit ( so ) interaction @xcite .
10,810
Suppose that you have an abstract for a scientific paper: parametric expressions are used to calculate the isothermal susceptibility , specific heat , order parameter , and correlation length along the critical isochore and coexistence curve from the asymptotic region to crossover region . these expressions are based on the minimal - subtraction renormalization scheme within the @xmath0 model . using two adjustable parameters in these expressions , we fit the theory globally to recently obtained experimental measurements of isothermal susceptibility and specific heat along the critical isochore and coexistence curve , and early measurements of coexistence curve and light scattering intensity along the critical isochore of @xmath1he near its liquid - vapor critical point . the theory provides good agreement with these experimental measurements within the reduced temperature range @xmath2 . . And you have already written the first three sentences of the full article: it is well known that thermodynamic quantities exhibit singularities asymptotically close to the critical point . the power - law behavior of these singularities , characterized by critical exponents and the concept of universality and scaling , have been successfully described by renormalization - group ( rg ) theory . away from the asymptotic region , thermodynamic quantities of real physical systems deviate from simple power - law behavior. Please generate the next two sentences of the article
. however , rg theory can still provide insight in understanding critical crossover behavior . there are two main field - theoretical renormalization - group schemes to treat critical - to - classical crossover phenomena .
10,811
Suppose that you have an abstract for a scientific paper: we propose a new simulation computational method to solve the reduced bcs hamiltonian based on spin analogy and submatrix diagonalization . then we further apply this method to solve superconducting energy gap and the results are well consistent with those obtained by bogoliubov transformation method . the exponential problem of @xmath0-dimension matrix is reduced to the polynomial problem of @xmath1-dimension matrix . it is essential to validate this method on a real quantum computer and is helpful to understand the many - body quantum theory . bcs theory@xcite and its subsequent extension is a well established theory to explain the mechanism of superconducting property . with two gross simplifications : the free electron approximation and the effective interaction approximation@xcite@xmath2 @xcite , a simplified bcs model is obtained and described by the reduced bcs hamiltonian . there has been much work on solving this hamiltonian . the mean field method is exact in the limit of large number of electrons where fluctuation can be neglected but disabled in the case of small number of electrons . since richardson s work@xcite in the 60 s to now , the exactly solvable bcs hamiltonian attracts much attention in connection with the problems in different areas of physics such as superconductivity , nuclear physics , physics of ultrasmall metallic grains . recently in _ l .- a . wu et al . _ s paper@xcite an nmr experiment scheme performing a polynomial - time simulation of pairing model was reported . based on this work we propose an explicit theory method to diagonalize the reduced bcs hamiltonian through the spin analogy and submatrix diagonalization . compared with the conventional method it is more useful in solving practical problem . the problem is solved in the spin space , which is convenient related to the qubit system . it gives a senseful alive method , quantum simulation , instead of the numerical diagonalization calculation . and it shows the potential to solve many -.... And you have already written the first three sentences of the full article: for metal element @xmath122@xcite , @xmath123 is the state density which have some spin directions on the fermi surface . @xmath124 according to the assumption@xmath125 formalism([renormal ] ) can be written as@xmath126 so from bcs theory , the cooper pair lies in the attraction area , ie @xmath127 . on substitution of @xmath128ev @xcite we can estimate @xmath129 , so @xmath108ev .. Please generate the next two sentences of the article
wu , m. s. byrd , and d. a. lidar , _ phys rev lett . _ * 89 * , 057904 ( 2002 ) ; j. dukelsky , j. m. romn , and g. sierra , _ phys rev lett . _ * 90 * , 249803 ( 2003 ) ; l .- a .
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Suppose that you have an abstract for a scientific paper: is a nearby x - ray transient which exhibited a fast and large x - ray outburst on sep . 15 , 1999 ( smith et al . 1999 ) . the wide field cameras and the narrow field instruments ( nfi ) on board _ bepposax _ observed at various stages of its activity before that , in the spring and fall of 1999 . the fluxes range between 0.012 and 0.3 crab units ( 2 - 10 kev ) . the nfi observation is unique because it is the longest semi - continuous observation of so far , and it offers a study of the spectrum at a relatively high resolution of 8% full width at half maximum at 6 kev . we discuss the observations with emphasis on the x - ray spectrum . a strong fe - k emission line was detected in with an equivalent width between 0.3 and 1 kev . the line energy is up to [email protected] kev and suggests the presence of highly ionized iron . we identify this as fluorescent emission from a photo - ionized plasma . the continuum spectrum is typical for a low - mass x - ray binary in which emission from an accretion disk corona plays an important role . there is no sign of an eclipse or periodic signal due to the binary orbit in this exposure , despite the fact that the twin jets seen at radio wavelengths suggest a high inclination angle . . And you have already written the first three sentences of the full article: the x - ray source was discovered in february , 1999 , independently with the wide field cameras ( wfcs ) on _ bepposax _ ( in t zand et al . 1999a ) and with the proportional counter array ( pca ) on _ rossixte _ ( ergo , its alternative designation xte j1819254 , markwardt et al . the wfc detection involved an hour - long flare with a peak of 80 mcrab on feb . 20. Please generate the next two sentences of the article
the first pca detection occurred during regular scans of the galactic center field , on feb . 18 . for some time
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Suppose that you have an abstract for a scientific paper: three experiments , among the lhc project , are getting ready to explore the b quark flavour sector . while atlas and cms are general purpose experiments , where the study of b mesons is going to proceed in parallel with the higgs boson and supersymmetry searches , the lhcb experiment is devoted to b physics studies . the key parameters entering the physics analyses and the performances achieved in all the three experiments are presented . given the large b physics program foreseen in the lhc experiments , the studies reported in this paper have been selected as those with higher likelihood to provide solid and interesting new results on standard model validation and new physics processes search with early data . . And you have already written the first three sentences of the full article: in the context of the large effort performed within the lhc @xcite experiments in order to finalize the construction of the standard model ( sm ) and to shed some light on the building blocks of its future extension , the b physics program plays a very important role . in a complementary way to the direct searches of higgs boson(s ) and new particles , the new physics ( np ) processes can be studied by making precision measurements in the flavour sector , where we do expect significant effects if the np scale is not completely decoupled from the tev energy range . in this framework , the b meson system is a natural place where to look . the @xmath0 mesons properties have already been studied in detail by the b - factories experiments ( cleo , babar , belle ) yielding and impressive agreement with the sm expectations .. Please generate the next two sentences of the article
the properties of the @xmath1 mesons , not available at e@xmath2e@xmath3 colliders(5s ) . the small statistics of @xmath1 mesons collected , will mainly be used to measure some absolute branching ratios .
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Suppose that you have an abstract for a scientific paper: the sgr b2 giant molecular cloud is claimed to be an x ray reflection nebula the reprocessing site of a powerful flare of the sgr a * source , occurred few hundred years ago . the shape of the x ray spectrum and the strength of the iron fluorescent line support this hypothesis . we argue that the most clean test of the origin of x rays from sgr b2 would be a detection of polarized emission from this source . epsf # 1= # 1#2=.99 = .99 # 1#2#3=.31 = .31 = .31 [ firstpage ] polarization scattering ism : individual : sgr b galaxy : centre x - rays : general . And you have already written the first three sentences of the full article: asca observations of the sgr b2 giant molecular cloud revealed very hard x ray spectrum with a very prominent iron fluorescent line at 6.4 kev ( koyama et al . , 1996 ) . this discovery provided an important confirmation of the hypothesis of sunyaev , markevitch and pavlinsky ( 1993 ) that the diffuse emission from the giant molecular clouds in the galactic centre region is at least partly due to reprocessed emission of a powerful x ray flare from the supermassive black hole sgr a*. the geometry of the problem suggests that such flare could have happened few hundred years ago . the morphology and the spectrum of the reprocessed emission have been modeled by sunyaev & churazov 1998 and murakami et al .. Please generate the next two sentences of the article
recent sax ( sidoli et al . , 2001 ) and chandra data ( murakami , koyama , maeda 2001a ) are broadly consistent with the assumption that reprocessed ( reflected ) emission is due to the past flare from sgr a*. main observational arguments in favor of this interpretation are : * remarkably hard shape of the sgr b2 x ray spectrum * extremely high flux in the neutral iron fluorescent line at 6.4 kev ( equivalent width @xmath012 kev ) . * the side of the cloud towards sgr a * is brighter in x rays than the opposite side .
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Suppose that you have an abstract for a scientific paper: a theoretical model for the folding of proteins containing disulfide bonds is introduced . the model exploits the knowledge of the native state to favour the progressive establishment of native interactions . at variance with traditional approaches based on native topology , not all native bonds are treated in the same way ; in particular , a suitable energy term is introduced to account for the special strength of disulfide bonds ( irrespective of whether they are native or not ) as well as their ability to undergo intra - molecular reshuffling . the model thus possesses the minimal ingredients necessary to investigated the much debated issue of whether the re - folding process occurs through partially structured intermediates with native or non - native disulfide bonds . this strategy is applied to a context of particular interest , the re - folding process of hirudin , a thrombin - specific protease inhibitor , for which conflicting folding pathways have been proposed . we show that the only two parameters in the model ( temperature and disulfide strength ) can be tuned to reproduce well a set of experimental transitions between species with different number of formed disulfide . this model is then used to provide a characterisation of the folding process and a detailed description of the species involved in the rate - limiting step of hirudin refolding . . And you have already written the first three sentences of the full article: the characterisation of the folding pathway of proteins is one of the fundamental problems in molecular biology and is under an increasing scientific attention due to the continuous advancements in experimental and theoretical biochemistry . after the work of anfinsen@xcite , who demonstrated that ribonuclease unfolds and refolds reversibly into its native ( active ) three - dimensional structure , it has generally been accepted that the primary sequence usually contains sufficient information to direct the complete folding process . what typically remains elusive to experimental and theoretical investigations is the pathway of this spontaneous process and the mechanisms that govern it .. Please generate the next two sentences of the article
a considerable progress in this direction is possible for proteins containing native disulfide bonds . the formation of disulfide bonds during the folding process can be controlled experimentally through the use of an appropriate thioldisulfide redox couple and thiol quenching agent@xcite . by these means
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Suppose that you have an abstract for a scientific paper: we analyze the energy band structure of a two - dimensional electron gas in a periodic magnetic field of a longitudinal antiferromagnet by considering a simple exactly solvable model . two types of states appear : with a finite and infinitesimal longitudinal mobility . both types of states are present at a generic fermi surface . the system exhibits a transition to an insulating regime with respect to the longitudinal current , if the electron density is sufficiently low . + pacs number(s ) : 75.50.rr , 75.70.ak = 8.75 in = -0.25 in = -0.75 in * electronic band structure in a periodic * * magnetic field * andrey krakovsky _ department of physics , new york university , new york , new york 10003 _ august 18 1995 the interest in the magnetoconductance properties of the two - dimensional electron gas in spatially periodic lateral magnetic fields has been further stimulated by the recent experimental availability of such systems @xcite . in the work of carmona et al . @xcite spatial modulation of a magnetic field was produced by means of equidistantly located superconducting stripes where magnetic vortices were trapped by impurities resulting in periodic inhomogeneity of the external magnetic field , while in the work of of ye et al . @xcite it was produced by deposition of ferromagnetic microstructures on top of the high - mobility two - dimensional ( 2d ) electron gas . vast theoretical efforts on 2d electron gas in an inhomogeneous external magnetic field range from the theory of momentum - dependent tunneling through a magnetic barrier @xcite to properties of electronic states and transoprt in a weakly spatially modulated magnetic field [ 47 ] . in this short paper we will be concerned with the one - electron energy band structure of the 2d electron gas under a periodic lateral magnetic field of an antiferromagnet , which is a limiting case of a strong periodic modulation . we will show that two types of states appear : with a finite and infinitesimal longitudinal.... And you have already written the first three sentences of the full article: fig . 1 . the external periodic magnetic field as modeled by ( [ eq : field ] ) . + fig . 2 . the band structure for a spinless problem compressed in the ( longitudinal ) @xmath12-direction . @xmath22 t , @xmath38 , @xmath24 , @xmath25 .. Please generate the next two sentences of the article
the states in the broad " bands ( upper quarter ) have a finite longitudinal mobility , while the longitudinal mobility of the states in the narrow " bands ( left and right quarters ) is infinitesimal . the band structure on a bigger scale . only every fourth of the narrow " bands is shown .
10,817
Suppose that you have an abstract for a scientific paper: antares is the first undersea neutrino telescope . it is in its complete configuration since may 2008 at about 2.5 km below the sea surface close to marseille . data from 12 lines are being analyzed and are producing first results . here we discuss first analysis results for 5 lines and 10 lines , and we also comment on the performance of the full detector . we show that the detector has capabilities for discriminating upgoing neutrino events from the much larger amount of downgoing atmospheric muons and that data and simulation are in good agreement . we then discuss the physics reach of the detector for what concerns point - like source and dark matter searches . . And you have already written the first three sentences of the full article: the long standing efforts for building cherenkov detectors in sea depths started with the dumand project that measured the muon vertical intensity at depths ranging between 2 and 4 km with a prototype line at a depth of 4.8 km about 30 km off - shore the island of hawaii in nov . 1987 @xcite . the project was canceled in 1995 , while in 1993 a first configuration of 36 phototubes ( pmts ) on 3 strings ( nt-36 ) was installed in lake baikal in siberia at the shallow depth of 1.1 km , 3.6 km off - shore @xcite .. Please generate the next two sentences of the article
the latest configuration of the experiment ( nt-200 + ) was put into operation in apr . 2005 , with an umbrella - like structure of 8 strings 72 m long , with pairs of up - looking and down - looking pmts with 37-cm photocatodes .
10,818
Suppose that you have an abstract for a scientific paper: we review the status of an ongoing long - term lattice investigation of the spectrum and structure of tetraquark candidates . we focus on the light scalar meson @xmath0 . first steps regarding the study of a possibly existing @xmath1 tetraquark are also outlined . . And you have already written the first three sentences of the full article: the nonet of light scalar mesons formed by @xmath2 , @xmath3 , @xmath0 and @xmath4 is poorly understood @xcite . compared to expectations based on a standard quark antiquark picture all nine states are rather light and their ordering is inverted . this can , however , naturally be explained assuming a tetraquark structure , which is also supported by certain decay channels , e.g. @xmath5 . here we report about the status of an ongoing long - term project with the aim to study such tetraquark candidates using lattice qcd .. Please generate the next two sentences of the article
we mainly focus on the @xmath0 . in section [ sec001 ] we summarize recently published results obtained with wilson twisted mass quarks , where diagrams with closed fermion loops ( also called `` singly disconnected diagrams '' ) have been neglected @xcite . in section [ sec455 ]
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Suppose that you have an abstract for a scientific paper: we present a synthetic spectral analysis of nearly the entire far ultraviolet international ultraviolet explorer ( iue ) archive of spectra of dwarf novae in or near outburst . the study includes 46 systems of all dwarf nova subtypes both above and below the period gap . the spectra were uniformly analyzed using synthetic spectral codes for optically thick accretion disks and stellar photospheres along with the best - available distance measurements or estimates . we present newly estimated accretion rates and discuss the implications of our study for disk accretion physics and cv evolution . . And you have already written the first three sentences of the full article: dwarf novae ( dne ) are a subclass of cataclysmic variables ( cvs ) , comprised of a low - mass , main sequence secondary star and a white dwarf ( wd ) primary . they are characterized by their quasi - periodic outburst episodes that are typically 2 - 6 mag in amplitude . the roche lobe - filling secondary loses gas through the inner langrangian point carrying substantial angular momentum that leads to the formation of a disk around the accreting white dwarf . a thermal - viscous instability known as. Please generate the next two sentences of the article
the disk instability model ( osaki 2005 and references therein ) causes the accretion disk to transition from a cool , quiescent , optically thin state to a stable state where the disk is much hotter , more luminous , optically thick and approaching a steady state . the disk is heated due to the release of gravitational potential energy as the accreted material spirals through the optically thick disk toward the wd surface .
10,820
Suppose that you have an abstract for a scientific paper: we carry out a feasibility study for the lattice qcd calculation of the neutron electric dipole moment ( nedm ) in the presence of the @xmath0 term . we develop the strategy to obtain the nucleon edm from the cp - odd electromagnetic form factor @xmath1 at small @xmath0 , in which nedm is given by @xmath2 where @xmath3 is the momentum transfer and @xmath4 is the nucleon mass . we first derive a formula which relates @xmath1 , a matrix element of the electromagnetic current between nucleon states , with vacuum expectation values of nucleons and/or the current . in the expansion of @xmath0 , the parity - odd part of the nucleon - current - nucleon three - point function contains contributions not only from the parity - odd form factors but also from the parity - even form factors multiplied by the parity - odd part of the nucleon two - point function , and therefore the latter contribution must be subtracted to extract @xmath1 . we then perform an explicit lattice calculation employing the domain - wall quark action with the rg improved gauge action in quenched qcd at @xmath5 gev on a @xmath6 lattice . at the quark mass @xmath7 , corresponding to @xmath8 , we accumulate 730 configurations , which allow us to extract the parity - odd part in both two- and three - point functions . employing two different dirac @xmath9 matrix projections , we show that a consistent value for @xmath1 can not be obtained without the subtraction described above . we obtain @xmath10 @xmath110.024(5 ) @xmath12fm for the neutron and @xmath10 0.021(6 ) @xmath12fm for the proton . . And you have already written the first three sentences of the full article: in the strong interaction , one of the most stringent constraints on possible violation of parity ( p ) and time - reversal ( t ) symmetry comes from the measurement of the electric dipole moment ( edm ) for neutron ( nedm ) and proton ( pedm ) @xmath13 . the current upper bound is given by |d_n| < 6.310 ^ -26e for neutron@xcite , and |d_p| < 5.4 10 ^ -24e for proton@xcite , which are estimated from the results for edm of mercury atom @xmath14 given by @xmath15 @xcite on the other hand , qcd , which is regarded as the fundamental theory of the strong interaction , allows a gauge invariant , renormalizable cp odd operator in the lagrangian , called the @xmath0 term : & & id^4xg_(x)g_(x ) [ l_qcd ] , g_(x ) = _ g_(x ) in euclidean space - time with @xmath16 the field strength of gluon . some model estimations@xcite yield |d_n| ~o(10 ^ -15~10 ^ -16 ) e , and this leads to a bound @xmath17 . hence @xmath0 must be small or. Please generate the next two sentences of the article
even must vanish in qcd . a smallness of @xmath0 in the qcd sector , however , is not protected in the presence of the electroweak sector of the standard model , where the quark mass matrix , arising from yukawa couplings to the higgs field , may be written as |^r_i(x ) m_ij^l_j(x ) + |^l_i(x ) m^_ij^r_j(x ) , where @xmath18 and @xmath19 represent left and right handed quark fields with flavor indices @xmath20 .
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Suppose that you have an abstract for a scientific paper: we report in - nqr and co - nmr experiments of cecoin@xmath0 that undergoes a superconducting transition with a record high @xmath1 = 2.3 k to date among heavy - fermion superconductors . at zero magnetic field , an anomalous temperature ( @xmath2 ) dependence of nuclear spin - lattice relaxation rate @xmath3 of @xmath4 in is explained by the relation @xmath5 based on the anisotropic spin - fluctuations model in case of the proximity to an antiferromagnetic ( afm ) quantum critical point ( qcp ) . the novel behavior of @xmath6 over a wide @xmath2 range of @xmath7 k arises because the staggered susceptibility almost follows the curie law @xmath8 with @xmath9 k and hence @xmath10 for @xmath11 . we highlight that the behavior @xmath6 is due to the proximity to the anisotropic afm qcp relevant with its layered structure , and is not associated with the afm qcp for isotropic 3d systems . we have also found that the afm spin fluctuations in cecoin@xmath0 are suppressed by small magnetic field so that @xmath12 k at @xmath13=0 increases to @xmath14 k at @xmath13 = 1.1 t , reinforcing that cecoin@xmath0 is closely located at the qcp . . And you have already written the first three sentences of the full article: heavy - fermion ( hf ) superconductivity has been a matter of interest with respect to an intimate interplay between magnetism and superconductivity since the discovery of hf superconductivity in cecu@xmath15si@xmath15 @xcite . from the extensive experimental and theoretical works on cecu@xmath15si@xmath15 , it has been revealed that the unconventional superconducting ( sc ) phase takes place at the border of an antiferromagnetic ( afm ) phase and even coexists with it when the superconductivity occurs very close to the afm phase . cecu@xmath15si@xmath15 was the only cerium - based hf superconductor at ambient pressure , before a new family of hf compounds ceirin@xmath0 and cecoin@xmath0 forming in two - dimensional ( 2d ) tetragonal structures was discovered to show superconductivity below @xmath1 = 0.4 k and 2.3 k , respectively @xcite . remarkably , the value of @xmath16 k for the latter is a record of high @xmath1 to date among previous examples .. Please generate the next two sentences of the article
meanwhile , the hf antiferromagnet cerhin@xmath0 , which crystallizes in the same crystal structure , was discovered to show superconductivity below @xmath1 = 2.2 k at pressures exceeding a critical pressure of 1.63 gpa @xcite . in cemin@xmath0 ( m = ir , co , and rh ) , the unconventional superconductivity with line - node gap is suggested from the power - law temperature ( @xmath2 ) dependence of specific heat @xcite , nuclear relaxation rate @xmath3 @xcite , penetration depth @xcite , thermal conductivity @xcite , and so on . systematic investigation of this new family of hf superconductors allows us to unravel a relationship between the occurrence of unconventional superconductivity and possible spin fluctuations in the normal state .
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Suppose that you have an abstract for a scientific paper: a five - dimensional ricci - flat cosmological solution is studied by assuming that the induced 4d matter contains two components : the usual fluid for dark matter as well as baryons and a scalar field with an exponential potential for dark energy . with use of the phase - plane analysis it is shown that there exist two late - time attractors one of which corresponds to a universe dominated by the scalar field alone and the other is a scaling solution in which the energy density of the scalar field remains proportional to that of the dark matter . it is furthermore shown that for this 5d scaling solution the universe expands with the same rate as in the 4d frw models and not relies on which 4d hypersurface the universe is located in the 5d manifold . . And you have already written the first three sentences of the full article: scalar fields play a central role in modern cosmology in driving inflation of the early universe and describing dark energy of the present epoch.@xmath0 observations predict that our universe contains roughly one - third of dark matter and baryons and two- thirds of dark energy.@xmath1 within the standard friedmann - robertson - walker ( frw ) models it was shown that there exist scaling solutions that are the unique late - time attractors whenever they exist.@xmath2 here , in this paper , we wish to look for scaling solutions in higher - dimensional cosmological models . in kaluza - klein theories as well as in brane world scenarios , our 4d universe is believed to be embedded in a higher - dimensional manifold . one of these models is the ricci - flat 5d cosmological solutions presented by liu and wesson.@xmath3 this model is 5d ricci - flat , implying that it is empty viewed from 5d .. Please generate the next two sentences of the article
however , as is known from the induced matter theory,@xmath4 4d einstein equations with matter could be recovered from 5d equations in apparent vacuum . this approach is guaranteed by campbell s theorem that any solution of the einstein equations in n - dimensions can be locally embedded in a ricci - flat manifold of ( n+1)-dimensions.@xmath5 in section ii , we suppose the 4d induced matter be composed of a perfect fluid and a scalar field . in section iii , we use phase - plane analysis to study the evolutions of the model . in section
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Suppose that you have an abstract for a scientific paper: we apply the diagrammatic monte carlo approach to three - dimensional fermi - polaron systems with mass - imbalance , where an impurity interacts resonantly with a noninteracting fermi sea whose atoms have a different mass . this method allows to go beyond frequently used variational techniques by stochastically summing all relevant impurity feynman diagrams up to a maximum expansion order limited by the sign problem . polaron energy and quasiparticle residue can be accurately determined over a broad range of impurity masses . furthermore , the spectral function of an imbalanced polaron demonstrates the stability of the quasiparticle and allows to locate in addition also the repulsive polaron as an excited state . the quantitative exactness of two - particle - hole wave - functions is investigated , resulting in a relative lowering of polaronic energies in the mass - imbalance phase diagram . tan s contact coefficient for the mass - balanced polaron system is found in good agreement with variational methods . mass - imbalanced systems can be studied experimentally by ultracold atom mixtures like @xmath0li@xmath1k . . And you have already written the first three sentences of the full article: one of the most general and successful concepts in physics is the separation of a physical system into a simpler , controlled subsystem that is interacting with a perturbing subsystem . a specific example of this method is given by a basic impurity problem , consisting of a noninteracting homogeneous medium and one particle disturbing it . in the case of a noninteracting fermi gas , this is called fermi - polaron problem@xcite .. Please generate the next two sentences of the article
this theoretical model can help to map out the phase diagram of a strongly population - imbalanced fermi gas@xcite , where the quasiparticle energy and effective mass serve as input parameters for landau - pomeranchuk hamiltonians@xcite helping to quantify zero temperature phase separation and the ground state energy of different phases . moreover , the @xmath2 fermi - polaron system was shown to undergo a transition of its own , featuring as possible ground states@xcite a polaronic spin-1/2 quasiparticle and the composite spin-0 molecule , consisting of the impurity and a single bath atom . however
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Suppose that you have an abstract for a scientific paper: even before the experimental discovery of spin- and charge - stripe order in la@xmath0nd@xmath1sr@xmath2cuo@xmath3 and la@xmath4ba@xmath2cuo@xmath3 at @xmath5 , stripe formation was predicted from theoretical considerations . nevertheless , a consistent description of the complex coexistence of stripe order with superconductivity has remained a challenge . here we introduce a hartree - fock decoupling scheme which unifies previous approaches and allows for a detailed analysis of the competition between antiferromagnetism and superconductivity in real and momentum space . we identify two distinct parameter regimes , where spin - stripe order coexists with either one- or two - dimensional superconductivity ; experiments on different striped cuprates are either compatible with the former or the latter regime . we argue that the cuprates at @xmath5 fall into an intermediate coupling regime with a crossover to long - range phase coherence between individual superconducting stripes . . And you have already written the first three sentences of the full article: since the discovery of high-@xmath6 superconductivity in la@xmath4ba@xmath2cuo@xmath3 @xcite , the analysis of many experiments has led to a complex phase diagram of cuprate materials , in part originating from the competition between antiferromagnetic ( af ) and superconducting ( sc ) correlations . both are induced by the coulomb repulsion on the copper @xmath7-orbitals in the cuo@xmath8 planes . at a critical hole - doping level antiferromagnetism and superconductivity are in balance , and details of the material or its environment determine which order is realized or whether a regime of coexistence or local phase separation exists . at very low temperatures. Please generate the next two sentences of the article
most cuprates show a transition from an af to a sc state , if the density of charge carriers exceeds a critical value , and superconductivity vanishes again beyond a higher carrier density , when the coulomb interaction becomes less significant . above the critical hole doping level , af correlations on reduced time and length scales persist and fluctuating antiferromagnetism may coexist with cooper pairing .
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Suppose that you have an abstract for a scientific paper: two recent experiments [ i. p. radu _ et al . _ , science @xmath0 , 899 ( 2008 ) and x. lin _ et al . _ , phys . rev . b @xmath1 , 165321 ( 2012 ) ] measured the temperature and voltage dependence of the quasiparticle tunneling through a quantum point contact in the @xmath2 quantum hall liquid . the results led to conflicting conclusions about the nature of the quantum hall state . in this paper , we show that the conflict can be resolved by recognizing different geometries of the devices in the experiments . we argue that in some of those geometries there is significant unscreened electrostatic interaction between the segments of the quantum hall edge on the opposite sides of the point contact . coulomb interaction affects the tunneling current . we compare experimental results with theoretical predictions for the pfaffian , @xmath3 , @xmath4 and @xmath5 states and their particle - hole conjugates . after coulomb corrections are taken into account , measurements in all geometries agree with the spin - polarized and spin - unpolarized halperin 331 states . . And you have already written the first three sentences of the full article: among numerous phases of two - dimensional electron gases ( 2deg ) , the even - denominator quantum hall states with the filling factors @xcite @xmath6 and @xmath7 are particularly interesting . in contrast to odd - denominator fractional quantum hall ( fqh ) liquids , they can not be explained by a straightforward generalization of the laughlin variational wave function . an early attempt to understand their nature led to the beautiful idea of non - abelian states of matter @xcite . in non - abelian systems , the types and positions of quasiparticles do not uniquely determine the quantum state . this results in unusual physics and may open a road to topological quantum computing @xcite . however , the existence of non - abelian quasiparticles has not been proven and the nature of the 5/2 state remains a puzzle . both abelian and non - abelian. Please generate the next two sentences of the article
candidate states were proposed as possible theoretical explanations of the 5/2 fqh effect @xcite . a number of methods @xcite were invented and several experiments @xcite were performed in an attempt to determine the right ground state . one approach @xcite consists in the measurement of the tunneling current through a quantum point contact ( qpc ) between the edges of a 5/2 fqh liquid .
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Suppose that you have an abstract for a scientific paper: we present an analysis of the minkowski functionals ( mfs ) describing the wmap three - year temperature maps to place limits on possible levels of primordial non - gaussianity . in particular , we apply perturbative formulae for the mfs to give constraints on the usual non - linear coupling constant @xmath0 . the theoretical predictions are found to agree with the mfs of simulated cmb maps including the full effects of radiative transfer . the agreement is also very good even when the simulation maps include various observational artifacts , including the pixel window function , beam smearing , inhomogeneous noise and the survey mask . we find accordingly that these analytical formulae can be applied directly to observational measurements of @xmath0 without relying on non - gaussian simulations . considering the bin - to - bin covariance of the mfs in wmap in a chi - square analysis , we find that the primordial non - gaussianity parameter is constrained to lie in the range @xmath1 ( @xmath2 c.l . ) using the q+v+w co - added maps . cosmology : early universe cosmic microwave background methods : statistical analytical . And you have already written the first three sentences of the full article: the existence of non - gaussianity in primordial density fields has the potential to provide a unique observational probe that will enable discrimination among wide variety of inflationary models of the early universe . versions of the inflation scenario based on the idea of a single slow - rolling scalar field predict levels of non - gaussianity too small to be observed . on the other hand , multi - field inflation models and models with a non - standard kinetic term for the inflaton may yield larger non - gaussian effects which could in principle be detected in current or next - generation observations ( e.g. * ? ? ? * ; * ? ? ?. Please generate the next two sentences of the article
* ; * ? ? ? * ; * ? ? ?
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Suppose that you have an abstract for a scientific paper: postulating the existence of a finite - mass mediator of t , p - odd coupling between atomic electrons and nucleons we consider its effect on permanent electric dipole moment ( edm ) of diamagnetic atoms . we present both numerical and analytical analysis for such mediator - induced edms and compare it with edm results for the conventional contact interaction . based on this analysis we derive limits on coupling strengths and carrier masses from experimental limits on edm of @xmath0hg atom . . And you have already written the first three sentences of the full article: the observational evidence for dark matter indicates the intriguing possibility of a `` dark sector '' extension to the standard model ( sm ) . dark matter in fact may be a small part of the dark sector or indeed many dark sectors could exist , each with their own `` dark forces '' and constituent particles . dark matter may be accompanied by hereto unknown gauge bosons ( `` dark force '' carriers , ) which can couple dark matter particles and ordinary particles with exceptionally weak couplings .. Please generate the next two sentences of the article
modern colliders can be blind to such new forces , even though the mass of the `` dark force '' carriers can be quite small . this is because the cross - sections of relevant processes for ordinary matter are so small that the `` dark force '' events are simply statistically insignificant and are discarded in high - energy experiments .
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Suppose that you have an abstract for a scientific paper: we investigate the properties of galaxies between the blue and the red sequence ( i.e. , the transition region , 4.5@xmath06 mag ) by combining ultraviolet ( uv ) and near - infrared imaging to 21 cm hi line observations for a volume - limited sample of nearby galaxies . we confirm the existence of a tight relation between colour and hi - fraction across all the range of colours , although outside the blue cloud this trend becomes gradually weaker . transition galaxies are divided into two different families , according to their atomic hydrogen content . ` hi - deficient ' galaxies are the majority of transition galaxies in our sample . they are found in high density environments and all their properties are consistent with a quenching of the star formation via gas stripping . however , while the migration from the blue cloud is relatively quick ( i.e. , @xmath11 gyr ) , a longer amount of time ( a few gyr at least ) seems required to completely suppress the star formation and reach the red sequence . at all masses , migrating ` hi - deficient ' galaxies are mainly disks , implying that the mechanism responsible for today s migration in clusters can not have played a significant role in the creation of the red sequence at high - redshift . conversely , ` hi - normal ' transition galaxies are a more heterogeneous population . a significant fraction of these objects show star formation in ring - like structures and evidence for accretion / minor - merging events suggesting that at least part of the hi reservoir has an external origin . the detailed evolution of such systems is still unclear , but our analysis suggests that , in at least two cases , galaxies might have migrated back from the red sequence after accretion events . interestingly , the hi available may be sufficient to sustain star formation at the current rate for several billion years . our study clearly shows the variety of evolutionary paths leading to the transition region and suggests that the transition galaxies may.... And you have already written the first three sentences of the full article: the last decades have seen the rise and success of the hierarchical paradigm for galaxy formation in a cold dark - matter dominated universe . although very powerful , the concordance model is still far from providing us with a complete and coherent view of how galaxies form and evolve . this is mainly because we still do not understand the physics involving the baryonic component .. Please generate the next two sentences of the article
the current challenge for galaxy formation and evolution studies is thus to improve our knowledge of the astrophysical processes responsible for _ transforming _ simple dark matter halos into the bimodal population of galaxies inhabiting today s universe . it is in fact well established that , when we look at their integrated optical colours , galaxies constitute a bimodal population ( e.g. , @xcite ) composed of a ` red sequence ' , dominated by old stellar populations , and a ` blue cloud ' where the vast majority of new stars in the universe are formed .
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Suppose that you have an abstract for a scientific paper: a new account of parameter setting during grammatical acquisition is presented in terms of generalized categorial grammar embedded in a default inheritance hierarchy , providing a natural partial ordering on the setting of parameters . experiments show that several experimentally effective learners can be defined in this framework . evolutionary simulations suggest that a learner with default initial settings for parameters will emerge , provided that learning is memory limited and the environment of linguistic adaptation contains an appropriate language . . And you have already written the first three sentences of the full article: grammatical acquisition proceeds on the basis of a partial genotypic specification of ( universal ) grammar ( ug ) complemented with a learning procedure enabling the child to complete this specification appropriately . the parameter setting framework of chomsky ( 1981 ) claims that learning involves fixing the values of a finite set of finite - valued parameters to select a single fully - specified grammar from within the space defined by the genotypic specification of ug . formal accounts of parameter setting have been developed for small fragments but even in these search spaces contain local maxima and subset - superset relations which may cause a learner to converge to an incorrect grammar ( clark , 1992 ; gibson and wexler , 1994 ; niyogi and berwick , 1995 ) . the solution to these problems involves defining default , unmarked initial values for ( some ) parameters and/or ordering the setting of parameters during learning .. Please generate the next two sentences of the article
bickerton ( 1984 ) argues for the bioprogram hypothesis as an explanation for universal similarities between historically unrelated creoles , and for the rapid increase in grammatical complexity accompanying the transition from pidgin to creole languages . from the perspective of the parameters framework , the bioprogram hypothesis claims that children are endowed genetically with a ug which , by default , specifies the stereotypical core creole grammar , with right - branching syntax and subject - verb - object order , as in saramaccan .
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Suppose that you have an abstract for a scientific paper: the exact five - dimensional charged black hole solution in lovelock gravity coupled to born - infeld electrodynamics is presented . this solution interpolates between the hoffmann black hole for the einstein - born - infeld theory and other solutions in the lovelock theory previously studied in the literature . the conical singularity of the metric around the origin can be removed by a proper choice of the black hole parameters . the thermodynamical properties of the solution are also analyzed and , in particular , it is shown that the behaviour of the specific heat indicates the existence of a stability transition point in the vacuum solutions . we discuss the similarities existing between this five - dimensional geometry and the three - dimensional black hole . like btz black hole , the lovelock black hole has an infinite lifetime . . And you have already written the first three sentences of the full article: the einstein tensor is the only symmetric and conserved tensor depending on the metric and its derivatives up to the second order , which is linear in the second derivatives of the metric . dropping the last condition , lovelock @xcite found the most general tensor satisfying the other ones . the obtained tensor is non linear in the riemann tensor and differs from the einstein tensor only if the space - time has more than 4 dimensions . therefore the lovelock theory is the most natural extension of general relativity in higher dimensional space - times .. Please generate the next two sentences of the article
the lovelock theory for a particular choice of the coefficients of the action could be thought as the gravitational analogue of born - infeld electrodynamics @xcite . in the last decades a renewed interest in both lovelock gravity and born - infeld electrodynamics has appeared because they emerge in the low energy limit of string theory @xcite .
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Suppose that you have an abstract for a scientific paper: we study the interaction - induced quantum correction @xmath0 to the conductivity tensor of electrons in two dimensions for arbitrary @xmath1 ( where @xmath2 is the temperature and @xmath3 the transport scattering time ) , magnetic field , and type of disorder . a general theory is developed , allowing us to express @xmath0 in terms of classical propagators ( `` ballistic diffusons '' ) . the formalism is used to calculate the interaction contribution to the longitudinal and the hall resistivities in a transverse magnetic field in the whole range of temperature from the diffusive ( @xmath4 ) to the ballistic ( @xmath5 ) regime , both in smooth disorder and in the presence of short - range scatterers . further , we apply the formalism to anisotropic systems and demonstrate that the interaction induces novel quantum oscillations in the resistivity of lateral superlattices . . And you have already written the first three sentences of the full article: [ i ] the magnetoresistance ( mr ) in a transverse field @xmath6 is one of the most frequently studied characteristics of the two - dimensional ( 2d ) electron gas @xcite . within the drude - boltzmann theory , the longitudinal resistivity of an isotropic degenerate system is @xmath6independent , _ xx(b)=_0=(e^2v_f^2 ) ^-1 , [ drude ] where @xmath7 is the density of states per spin direction , @xmath8 the fermi velocity , and @xmath3 the transport scattering time . deviations from the constant @xmath9 are customarily called a positive or negative mr , depending on the sign of the deviation .. Please generate the next two sentences of the article
there are several distinct sources of a non - trivial mr , which reflect the rich physics of the magnetotransport in 2d systems . first of all , it has been recognized recently that even within the quasiclassical theory memory effects may lead to strong mr @xcite .
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Suppose that you have an abstract for a scientific paper: we study the dependence of the ground state energy on an applied aharonov - bohm flux @xmath0 for the luttinger model with large momentum scattering . employing the method of finite size bosonization , we show that for systems with a spin gap but with gapless charge degrees of freedom , the ground state energy has an exact period of @xmath1 , i. e. _ half _ a flux quantum , in the limit of large system size @xmath2 . finite size corrections are found to vanish exponentially in @xmath2 . this behavior is contrasted to that of the spin gapless case , for both even and odd particle number . generalizations to finite temperature are also discussed . . And you have already written the first three sentences of the full article: models of interacting electrons in one spatial dimension are very valuable for the understanding of strongly correlated systems . this is because there exist theoretical methods enabling us to determine their physical properties reliably . indeed , by combining perturbative renormalization group@xcite , bosonization , and bethe ansatz techniques , a wealth of interesting phases in one dimension has been discovered . while some properties of these phases are unique in one dimension , others have their higher dimensional analogs . for example the independent gapless spin- and charge- excitations and the vanishing quasiparticle weight of the _ luttinger liquid _ @xcite are unique in 1d .. Please generate the next two sentences of the article
however , the fact that it has a finite charge compressibility and drude weight is analogous to a normal metal in higher dimensions . as another example , like systems in higher dimensions , a mott insulating state is realized at half filling for repulsive interactions . however , the fact that antiferromagnetic long range order is absent and that spin 1/2 excitation exists in the half - filled mott state are special features of 1d .
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Suppose that you have an abstract for a scientific paper: the propagation of solitons in dipolar bec in a trap potential with a barrier potential is investigated . the regimes of soliton transmission , reflection and splitting as a function of the ratio between the local and dipolar nonlocal interactions are analyzed analytically and numerically . coherent splitting and fusion of the soliton by the defect is observed . the conditions for fusion of splitted solitons are found . in addition the delocalization transition governed by the strength of the nonlocal dipolar interaction is presented . predicted phenomena can be useful for the design of a matter wave splitter and interferometers using matter wave solitons . . And you have already written the first three sentences of the full article: the bose - einstein condensate ( bec ) of chromium ( @xmath0cr ) , where long range dipolar interaction between atoms plays the dominant role , is a novel kind of nonlinear system becoming available to experiments @xcite . properties of dipole - dipole ( dd ) interactions , namely their long range character and anisotropy , allow dipolar condensates to exhibit many unusual properties not found in becs with just contact interactions @xcite . in particular the existence of stable isotropic and anisotropic two dimensional ( 2d ) solitons has been predicted for such cold quantum gases @xcite . recently the bright solitons in quasi-1d dipolar bec with competing local and nonlocal interactions have been studied in works @xcite .. Please generate the next two sentences of the article
the long - range dipolar interactions become dominant when the local part is detuned to zero by the feshbach resonance ( fr ) techniques , as in the experiment on observation of anderson localization in non - interacting cold quantum gases @xcite . in this particular case the pure dipolar bright soliton can be observed .
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Suppose that you have an abstract for a scientific paper: polarization - sensitive , microwave kinetic inductance detectors ( mkids ) are under development for the next - generation blast instrument ( blast - tng ) . blast - tng is a balloon - borne submillimeter polarimeter designed to study magnetic fields in diffuse dust regions and molecular clouds . we present the design and performance of feedhorn - coupled , dual - polarization sensitive mkids fabricated from tin / ti multilayer films , which have been optimized for the 250 @xmath0 m band . measurements show effective selection of linear polarization and good electrical isolation between the orthogonally crossed x and y detectors within a single spatial pixel . the detector cross - polar coupling is @xmath13% . passband measurements are presented , which demonstrate that the desired band - edges ( 1.0 - 1.4 thz ) have been achieved . we find a near linear response to the optical load from a blackbody source , which has been observed in previous devices fabricated from tin . blackbody - coupled noise measurements demonstrate that the sensitivity of the detectors is limited by photon - noise when the optical load is greater than 1 pw . . And you have already written the first three sentences of the full article: the next generation blast experiment @xcite ( blast - tng ) is a suborbital balloon payload that seeks to map polarized dust emission in the 250 @xmath0 m , 350 @xmath0 m and 500 @xmath0 m wavebands . the instrument utilizes a stepped half - wave plate to reduce systematics . the general requirement of the detectors is that they are photon - noise - limited and dual - polarization sensitive . to achieve this goal. Please generate the next two sentences of the article
, we are developing three monolithic arrays of cryogenic sensors , one for each waveband . each array is feedhorn - coupled and each spatial pixel consists of two orthogonally spaced polarization - sensitive microwave kinetic inductance detectors @xcite ( mkids ) fabricated from a ti / tin multilayer film . in previous work
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Suppose that you have an abstract for a scientific paper: five years ago , lane hughston showed that some of the symmetric informationally complete positive operator valued measures ( sics ) in dimension 3 coincide with the hesse configuration ( a structure well known to algebraic geometers , which arises from the torsion points of a certain elliptic curve ) . this connection with elliptic curves is signalled by the presence of linear dependencies among the sic vectors . here we look for analogous connections between sics and algebraic geometry by performing computer searches for linear dependencies in higher dimensional sics . we prove that linear dependencies will always emerge in weyl - heisenberg orbits when the fiducial vector lies in a certain subspace of an order 3 unitary matrix . this includes sics when the dimension is divisible by 3 or equal to 8 mod 9 . we examine the linear dependencies in dimension 6 in detail and show that smaller dimensional sics are contained within this structure , potentially impacting the sic existence problem . we extend our results to look for linear dependencies in orbits when the fiducial vector lies in an eigenspace of other elements of the clifford group that are not order 3 . finally , we align our work with recent studies on representations of the clifford group . . And you have already written the first three sentences of the full article: symmetric informationally - complete positive operator - valued measures ( sics ) @xcite represent a general form of measurement in quantum theory . as the more familiar projective measurements are associated to an orthonormal basis in hilbert space , a sic is associated to an over - complete set of @xmath0 unit vectors in @xmath1 such that the absolute value of the scalar product between any distinct two is always constant , i.e. @xmath2 @xmath3 sics have practical applications in quantum state tomography @xcite , quantum communication @xcite , quantum cryptography @xcite , classical high precision radar @xcite and classical speech recognition @xcite . a significant amount of work is aimed towards proving their existence in all dimensions although no general proof is currently known . numerical studies have successfully found sics when @xmath4 @xcite and analytical solutions have been published for 20 of these dimensions ( see references in @xcite plus recent solutions for @xmath5 in @xcite and @xmath6 in @xcite ) .. Please generate the next two sentences of the article
such results promote the belief that sics can always be found , but the current solutions are rather dimension - dependent and do not provide an overall coherent picture . all known sics are group covariant , meaning they can be obtained from the action of a group on a single fiducial vector .
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Suppose that you have an abstract for a scientific paper: we demonstrate the large scale effects of the interplay between shape and hard core interactions in a system with left- and right - pointing arrowheads @xmath0 on a line , with reorientation dynamics . this interplay leads to the formation of two types of domain wall , diffusive ( @xmath1 ) and static ( @xmath2 ) . the correlation length in the equilibrium state diverges exponentially with increasing arrowhead density , with an ordered state of like orientations arising in the limit . in time , the approach to the ordered state is described by a coarsening process governed by the kinetics of domain wall annihilation @xmath3 , quite different from @xmath4 kinetics pertinent to the glauber - ising model . the survival probability of a finite set of walls is shown to decay exponentially in time , in contrast to the power law decay known for @xmath4 . in the thermodynamic limit with a finite density of walls , coarsening as a function of time @xmath5 is studied by simulation . while the number of walls falls as @xmath6 , the fraction of persistent arrowheads decays as @xmath7 where @xmath8 is close to @xmath9 , quite different from the ising value . the global persistence too has @xmath10 , as follows from a heuristic argument . in a generalization where the @xmath2 walls diffuse slowly , @xmath8 varies continuously , increasing with increasing diffusion constant . . And you have already written the first three sentences of the full article: one - dimensional systems of interacting particles or spins show interesting collective effects when the system approaches an ordered state as the temperature approaches zero @xcite . the static properties of such systems are dominated by a diverging correlation length , and generally well understood . however , dynamic properties are more varied and intricate .. Please generate the next two sentences of the article
of particular interest is the way in which domains of ordered phases grow when the system is quenched from a disordered state to an ordered one . the coarsening dynamics that ensues can often be modelled through the kinetics of domain walls ; a well - known example is the glauber - ising chain , in which domain walls diffuse and annihilate upon contact , corresponding to the kinetics of the reaction @xmath11 0 @xcite . in this paper
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Suppose that you have an abstract for a scientific paper: we report on high - field magnetization , specific - heat and electron spin resonance ( esr ) studies of the quasi - two - dimensional spin-1/2 heisenberg antiferromagnet [ cu(pyz)@xmath0(hf@xmath0)]pf@xmath1 . the frequency - field diagram of esr modes below @xmath2 k is described in the frame of the mean - field theory , confirming a collinear magnetic structure with an easy - plane anisotropy . the obtained results allowed us to determine the anisotropy / exchange interaction ratio , @xmath3 , and the upper limit for the inter / intra - plane exchange - interaction ratio , @xmath4 . it is argued that despite the onset of 3d long - range magnetic ordering the magnetic properties of this material ( including high - magnetic - field magnetization and non - monotonic field dependence of the nel temperature ) are strongly affected by two - dimensional spin correlations . . And you have already written the first three sentences of the full article: recently , a considerable amount of attention has been devoted to the theoretical and experimental investigation of two - dimensional ( 2d ) quantum spin systems . in case of the ideal 2d heisenberg antiferromagnet ( af ) on a square lattice , the magnetic long - range order is suppressed by zero - point fluctuations at any finite temperature.@xcite however , the presence of an easy - axis anisotropy can induce a finite - temperature phase transition into the nel ordered state.@xcite on the other hand , for an easy - plane anisotropy , a transition of the berezinski - kosterlitz - thouless ( bkt ) type @xcite was proposed , where the high - temperature disordered phase can be described as a gas of vortices . below the bkt transition ( @xmath5 ) , the vortices are bound in vortex - antivortex pairs , and the spin - spin correlation decay changes from exponential to algebraic.@xcite a crossover from the isotropic to xy behavior in low fields has been predicted for 2d heisenberg af.@xcite interplane interactions ( which are always present in real materials ) can significantly modify the ground - state properties of quasi-2d systems , inducing for instance a phase transition with three - dimensional ( 3d ) long - range magnetic order . due to the onset of 3d ordering in most real materials , the critical behavior of diverging quantities as anticipated for ideal 2d systems at @xmath5 is hardly observable experimentally .. Please generate the next two sentences of the article
the quasi-2d heisenberg af model with interplane interactions can be described by the hamiltonian @xmath6 with @xmath7 , where @xmath8 is the bohr magneton , @xmath9 and @xmath10 are the intra- and interplane exchange interactions , respectively , and @xmath11 and @xmath12 correspond to nearest - neighbor spin pairs formed in the directions parallel and perpendicular to the @xmath13 planes , respectively . the variation of the ratio @xmath14 allows to study nicely the rich phase diagram of quasi-2d magnetic systems , including the transition from a 2d heisenberg af ( @xmath15 ) to the 3d heisenberg af ( @xmath16 ) .
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Suppose that you have an abstract for a scientific paper: single photon sources ( sps ) are a fundamental building block for optical implementations of quantum information protocols . among spss , multiple crystal heralded single photon sources seem to give the best compromise between high pair production rate and low multiple photon events . in this work , we study their performance in a practical quantum key distribution experiment , by evaluating the achievable key rates . the analysis focuses on the two different schemes , symmetric and asymmetric , proposed for the practical implementation of heralded single photon sources , with attention on the performance of their composing elements . the analysis is based on the protocol proposed by bennett and brassard in 1984 and on its improvement exploiting decoy state technique . finally , a simple way of exploiting the post - selection mechanism for a passive , one decoy state scheme is evaluated . . And you have already written the first three sentences of the full article: the goal of quantum key distribution ( qkd ) is to allow two distant parties , alice and bob , to share a secret key even in the presence of an eavesdropper , eve . since in quantum mechanics measurements irremediably perturb the systems , it is impossible for an eavesdropper to extract useful information without being noticed . quantum key distribution protocols , like the bennett - brassard 1984 ( bb84 ) protocol @xcite , are proven to be unconditionally secure , when using single photons . however , due to the spread of laser systems and the difficulty of realizing true single photon sources , most qkd implementations use attenuated pulsed lasers as sources .. Please generate the next two sentences of the article
the need to avoid multi - photon pulses , that can leak information through the photon number splitting ( pns ) attack @xcite , requires a low mean photon number per pulse . this , however , increments the incidence of pulses containing no photons , thus limiting the key generation rate . the incidence of the pns attack can be limited using the decoy state technique @xcite , at the expenses of the necessity to modulate the laser intensity .
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Suppose that you have an abstract for a scientific paper: a fully nonlinear numerical simulation of two - dimensional faraday waves between two incompressible and immiscible fluids is performed by adopting the phase - field method with the cahn - hilliard equation due to jacqmin ( _ j . comput . phys . _ , vol . 155 , 1999 , pp . 96 - 127 ) . its validation is checked against the linear theory . in the nonlinear regime , qualitative comparison is made with an earlier vortex - sheet simulation of two dimensional faraday waves by wright , yon & pozrikidis ( _ j . fluid mech . _ , vol . 400 , 2000 , pp . 1 - 32 ) . the vorticity outside the interface region is studied in this comparison . the period tripling state , which is observed in the quasi - two dimensional experiment by jiang , perlin & schultz ( _ j . fluid mech . _ , vol . 369 , 1998 , pp . 273 - 299 ) , is successfully simulated with the present phase - field method . faraday waves , multiphase flow , parameteric instability . And you have already written the first three sentences of the full article: faraday waves , which typically refer to complex patterns of standing waves on a fluid surface in an oscillating container , are among the classical problems of fluid mechanics @xcite . the phenomenon has been a representative example of parametric instabilities @xcite . as is often the case with fluid mechanics , even classical phenomena are often not well understood in nonlinear regimes . indeed , continuing experiments on faraday waves beyond the linear regimes reveal intriguing new features , which include snake - like structures in drop - confined faraday waves @xcite , a turbulent state mediated by defects of the pattern @xcite and so - called oscillons @xcite . these surprising findings would probably be outside of the applicable range of the weakly nonlinear theories , such as the one developed by @xcite , on selection of various patterns of faraday waves .. Please generate the next two sentences of the article
hence , to understand these phenomena , fully nonlinear numerical simulations of the faraday systems , which can be complementary to laboratory experiments , play an indispensable role as discussed in @xcite . perhaps the first such simulation , in which the motions of both the top and bottom fluids are simultaneously simulated , was performed recently by @xcite .
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Suppose that you have an abstract for a scientific paper: we study the three - dimensional atomic bose gas using renormalization group techniques . using our knowledge of the microscopic details of the interatomic interaction , we determine the correct initial values of our renormalization group equations and thus obtain also information on nonuniversal properties . as a result , we can predict for instance the critical temperature of the gas and the superfluid and condensate density of the bose - einstein condensed phase in the regime @xmath0 . . And you have already written the first three sentences of the full article: after a long history in which a large number of experimental groups around the world contributed to the development of succesful methods to master stabilization and cooling of dilute bose gases , last year the aim of achieving bose - einstein condensation in such a system was finally reached . indeed , a macroscopic occupation of the one - particle ground state was irrefutably observed in magnetically trapped and evaporatively cooled alkali gas samples of @xmath1rb and @xmath2na using relatively simple time - of - flight measurements @xcite . the transition that was claimed to be seen in an experiment using @xmath3li was less convincing @xcite . in the latter case ,. Please generate the next two sentences of the article
the interatomic interaction is effectively attractive and the potential has a negative scattering length @xmath4 . therefore , bose - einstein condensation in this system is preempted by a first order phase transition to a liquid or solid phase in the homogeneous case @xcite .
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Suppose that you have an abstract for a scientific paper: results of measurements of the longitudinal magnetic field in a hot accretion spot in three classical t tauri stars ( ctts ) are presented . the magnetic field in the formation region of the narrow component of the emission line hei 5876 was found for each star in our sample at a level of more than 2@xmath0 in case of ds tau we have found the field in the narrow components of nai d lines , which was equal to @xmath1 kg , i.e. it was equal to the field measured on the narrow component of hei 5876 . our results indicate that the magnetic field in the hot spots can be studied for ctts down to 13@xmath2 that allow in the future to double a number of ctts with measured field in the accretion zone . . And you have already written the first three sentences of the full article: classical t tauri stars ( ctts ) are young ( @xmath3 yr ) , low mass @xmath4 stars at the stage of gravitational contraction towards the main - sequence , activity of which is caused by magnetospheric accretion of protoplanetary disc matter @xcite . inner regions of the accretion disc are truncated by the stellar magnetic field and disc s matter slides down toward the star along the field lines . having reached the dense layers of the stellar atmosphere , matter is decelerated in the accretion shock , behind the front of which the most part of its kinetic energy converts into the short - wavelength radiation .. Please generate the next two sentences of the article
one half of the radiation flux irradiates the star , producing the so - called hot spot on its surface . simulations , performed by dodin & lamzin @xcite , confirm the hypothesis , suggested by batalha et al .
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Suppose that you have an abstract for a scientific paper: dynamical searches find central dark objects candidate supermassive black holes ( bhs ) in at least 34 galaxies . the demographics of these objects lead to the following conclusions : \(1 ) bh mass correlates with the luminosity of the bulge component of the host galaxy , albeit with considerable scatter . the median bh mass fraction is 0.15% of the mass of the bulge . the quartiles are 0.09% and 0.7% . \(2 ) bh mass correlates with the mean velocity dispersion of the bulge component inside its effective radius , i.e. , with how strongly the bulge stars are gravitationally bound to each other . for the best bh mass determinations , the scatter is consistent with the measurement errors . \(3 ) bh mass correlates with the luminosity of the high - density central component in disk galaxies independent of whether this is a real bulge ( a mini - elliptical ) or a `` pseudobulge '' ( believed to form via inward transport of disk material ) . \(4 ) bh mass does not correlate with the luminosity of galaxy disks . if pure disks contain bhs ( and agn observations argue that some do ) , then their bh mass fractions are much smaller than the canonical 0.15% for bulges . these results lead to the following conclusions : \(a ) present observations show no dependence of bh mass on the details of whether bh feeding happens rapidly during a collapse or slowly via secular evolution of the disk . \(b ) the above results increasingly support the hypothesis that the major events that form a bulge or elliptical galaxy and the main growth phases of its bh when it shone as an agn were the same events . # 1_#1 _ # 1_#1 _ = # 1 1.25 in .125 in .25 in . And you have already written the first three sentences of the full article: = 15000 = 15000 a major payoff period for the _ hubble space telescope _ ( hst ) is under way , as the space telescope imaging spectrograph ( stis ) starts to produce black hole detections routinely and in large numbers . eight new bh detections are available from nuker team work ( gebhardt et nuk .. Please generate the next two sentences of the article
2000b ) , and improved observations or new detections are available for 6 more ( verdoes kleijn et al . 2000 ; bower et al .
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Suppose that you have an abstract for a scientific paper: optical lattices with a large spacing between the minima of the optical potential can be created using the angle - tuned geometry where the 1-d periodic potential is generated by two propagating laser beams intersecting at an angle different from @xmath0 . the present work analyzes the coherent transport for the case of this geometry . we show that the potential depth can be kept constant during the transport by choosing a _ magic _ value for the laser wavelength . this value agrees with that of the counterpropagating laser case , and the magic wavelength does not depend of the optical lattice geometry . moreover , we find that this scheme can be used to implement controlled collision experiments under special geometric conditions . finally we study the transport of hyperfine - zeeman states of rubidium 87 . . And you have already written the first three sentences of the full article: neutral atoms trapped in an artificial periodic potential formed by laser light , the so called far detuned optical lattice , have been proposed as the individual qubits for quantum information processing . in an optical lattice , neutral atoms can be trapped in the intensity maxima ( or minima ) of a standing wave light field owing to the optical dipole force . a configuration with one single atom trapped in each site of the optical lattice is realized in the configuration of a mott - insulator transition associated to the loading of bose - einstein condensates ( becs ) in optical lattices@xcite . in order to realize quantum gates with neutral atoms within the ideal environment of the mott insulator several schemes have been proposed .. Please generate the next two sentences of the article
the common idea is to control the quantum atomic states through the preparation and coherent manipulation of atomic wave - packets by means of application of standard laser cooling and spectroscopic techniques . by using spin dependent , or more precisely state dependent , optical lattice potentials , the control can be applied independently to multiple atomic qubits based on different internal states .
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Suppose that you have an abstract for a scientific paper: an effective field theory with hadrons and photons is constructed , where the hadronic parameters are determined by fitting elastic @xmath0n scattering data . the predicted pion - induced @xmath1-production on the nucleon agrees well with the data . the hadronic model is then used to describe the final - state interaction in photoinduced processes . we present a consistent description of pion photoproduction in the e@xmath2-channel and of the total cross sections for photoinduced @xmath1-production on the proton as well as on the deuteron . . And you have already written the first three sentences of the full article: a prerequisite for a theoretical description of the properties of @xmath1-mesons in hadronic matter and the possible consequences for @xmath1-production in heavy - ion collisions is a reliable model for elementary processes like @xmath1-production in hadronic collisions and in photo - induced reactions . new accurate data on the photoproduction of @xmath1-mesons off protons @xcite as well as off deuterons @xcite provide strong constraints on models for the elementary @xmath1-meson hadron and photon hadron interactions . we present such a model which satisfies the requirements of unitarity and gauge invariance .. Please generate the next two sentences of the article
an effective field theory is constructed , where the hadronic coupling constants and resonance masses are determined by fitting data on elastic @xmath0n scattering . the consistency of our model is checked by comparing the cross section for the inelastic channel @xmath0n@xmath3n with experiment ( see ref .
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Suppose that you have an abstract for a scientific paper: we discuss how to formulate lattice gauge theories in the tensor network language . in this way we obtain both a consistent - truncation scheme of the kogut - susskind lattice gauge theories and a tensor network variational ansatz for gauge invariant states that can be used in actual numerical computations . our construction is also applied to the simplest realization of the quantum link models / gauge magnets , and provides a clear way to understand their microscopic relation with the kogut - susskind lattice gauge theories . we also introduce a new set of gauge invariant operators that modify continuously rokshar - kivelson wave functions , and can be used to extend the phase diagrams of known models . as an example we characterize the transition between the deconfined phase of the @xmath0 lattice gauge theory and the rokshar - kivelson point of the u(1 ) gauge magnet in 2d in terms of entanglement entropy . the topological entropy serves as an order parameter for the transition , but not the schmidt gap . tensor network ( tn ) techniques are starting to play an important role in our understanding of many - body quantum systems , both on the lattice and in the continuum . they can be used as a framework to classify the phases of quantum matter @xcite , or as powerful numerical ansatz in actual computations of 1d @xcite and 2d strongly correlated quantum magnets @xcite , fermionic systems @xcite , or anyonic systems @xcite . they have also recently made their way into quantum chemistry as computational tool to study the structure of molecules from the first principles @xcite . while numerical simulations based on monte carlo ( mc ) are still the most successful techniques in some of these fields , tns start to provide viable alternatives to them , particularly in those contexts where mc has troubles , such as the physics of frustrated anti - ferromagnets @xcite , and the real time evolution of out of equilibrium systems @xcite . at present , the main limitation of numerical tn.... And you have already written the first three sentences of the full article: here we briefly summarize the most important results of our paper so that the reader interested in applying our formalism to specific models will easily find the relevant material . - we derive the tn representation of the standard ks lgt hamiltonian for arbitrary compact groups in eq . [ eq : one_site_op ] , [ eq : u_ks ] , [ eq : h_ks ] .. Please generate the next two sentences of the article
- we present an extra gauge invariant operator that can be added to the ks hamiltonian to explore generalized ks lgt for arbitrary compact groups in eq . [ eq : v_op ] .
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Suppose that you have an abstract for a scientific paper: although quintessence models have many attractive cosmological features , they face two major difficulties . first , it has not yet been possible to find one which convincingly realizes the goal of explaining present - day cosmic acceleration generically using only attractor solutions . second , quintessence has proven difficult to obtain within realistic microscopic theories , largely due to two major obstructions . both of these difficulties are summarized in this article , together with a recent proposal for circumventing the second of them within a brane - world context . it is shown that this proposal leads to a broader class of dynamics for the quintessence field , in which its couplings slowly run ( or : ` walk ' ) over cosmological time scales . the walking of the quintessence couplings opens up new possibilities for solving the first problem : that of obtaining acceptable transitions between attractor solutions . . And you have already written the first three sentences of the full article: the discovery by cosmologists that the universe is currently dominated by two distinct types of unknown forms of matter is a development with truly copernican implications for our picture of the universe as a whole . we have known for some time that visible matter likes to cluster on large scales into galaxies and galaxy clusters , with 90% or more of the mass of these objects consisting of an unknown nonbaryonic ` dark matter ' @xcite . the more recent surprise was the discovery that this clustered dark matter itself makes up no more than 30% of the overall energy density of the universe , with the remaining 70% apparently consisting of a different kind of unknown substance , sometimes called ` dark energy ' @xcite .. Please generate the next two sentences of the article
it is absolutely breathtaking that so little is known about these two most abundant forms of matter . what is known is usually expressed in terms of their equations of state , through the ratio of pressure to energy density , @xmath0 .
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Suppose that you have an abstract for a scientific paper: this is a technical note where we solve the additive eigenvalue problem associated to a dynamics of a 2d - traffic system . the traffic modeling is not explained here . it is available in @xcite . it consists of a microscopic road traffic model of two circular roads crossing on one junction managed with the priority - to - the - right rule . it is based on petri nets and minplus algebra . one of our objectives in @xcite was to derive the fundamental diagram of 2d - traffic , which is the relation between the density and the flow of vehicles . the dynamics of this system , derived from a petri net design , is non monotone and additively homogeneous of degree 1 . in this note , we solve the additive eigenvalue problem associated to this dynamics . . And you have already written the first three sentences of the full article: in this note we solve the additive eigenvalue problem ( or the time - independent system ) associated to the dynamics of a basic 2d - traffic model considered in @xcite . it is a system of two circular roads crossing on one junction managed with the _ priority - to - the - right _ rule . the model is based on petri nets and on minplus algebra @xcite .. Please generate the next two sentences of the article
it is an extension to an existing 1d - traffic model @xcite , which gives the average speed of vehicles on one circular road as an eigenvalue of a minplus matrix , and thus allows the derivation of the fundamental diagram of 1d - traffic ( the relation between the density and the flow of vehicles on the road ) . we give a solution of the eigenvalue problem .
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Suppose that you have an abstract for a scientific paper: we consider a homogeneous bose - fermi mixture , with the boson - fermion interaction tuned by a fano - feshbach resonance , in the presence of mass and density imbalance between the two species . by using many - body diagrammatic methods , we first study the finite - temperature phase diagram for the specific case of the mass - imbalanced mixture @xmath0rb @xmath1k for different values of the density imbalance . we then analyse the quantum phase transition associated with the disappearance at zero temperature of the boson condensate above a critical boson - fermion coupling . we find a pronounced dependence of the critical coupling on the mass ratio and a weak dependence on the density imbalance . for a vanishingly small boson density , we derive , within our approximation , the asymptotic expressions for the critical coupling in the limits of small and large mass ratios . these expressions are relevant also for the polaron - molecule transition in a fermi mixture at small and large mass ratios . the analysis of the momentum distribution functions at sufficiently large density imbalances shows an interesting effect in the bosonic momentum distribution due to the simultaneous presence of composite fermions and unpaired fermions . . And you have already written the first three sentences of the full article: an impressive series of experiments has been realized with ultracold atomic gases over the last years , reproducing systems , or physical situations , relevant to several areas of physics . the use of fano - feshbach resonances to control the interaction strength between particles , in particular , has been the cornerstone of many of these recent experimental achievements . besides providing analog quantum models and simulators for systems of interest in different fields of physics , ultracold gases offer also the possibility to construct novel many - body systems with no corresponding counterparts in other domains of physics .. Please generate the next two sentences of the article
resonant bose - fermi mixtures constitute an interesting example in this respect , and have been the object of active theoretical and experimental investigation recently . nonresonant bose - fermi mixtures were initially studied theoretically and experimentally in @xcite and @xcite , respectively .
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Suppose that you have an abstract for a scientific paper: we determine o(@xmath0 ) boundary improvement coefficients up to 1-loop level for the schrdinger functional coupling with improved gauge actions including plaquette and rectangle loops . these coefficients are required to implement 1-loop o(@xmath0 ) improvement in full qcd simulations for the coupling with the improved gauge actions . to this order , lattice artifacts of step scaling function for each improved gauge action are also investigated . in addition , passing through the sf scheme , we estimate the ratio of @xmath1-parameters between the improved gauge actions and the plaquette action more accurately . . And you have already written the first three sentences of the full article: the @xmath2-scheme now becomes the standard renormalization scheme for the definition of the strong coupling constant . the measured coupling constant @xmath3 in some experiment at relatively high energy is converted to @xmath4 at some representative scale by perturbation theory . the current world average of such estimates gives @xmath5 .. Please generate the next two sentences of the article
lattice qcd calculations , on the other hand , have a potential ability to determine the the strong coupling constant from the experimental inputs at low ( hadronic ) energy scale . in order to compare the coupling constant obtained at low energy by the lattice calculations with @xmath4 obtained at high energy , the schrdinger functional scheme has been proposed by the alpha collaboration @xcite , and the scheme is shown to be successful . at present , the results on the running coupling constant of two massless flavor qcd are reported @xcite . in the real world
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Suppose that you have an abstract for a scientific paper: equilibrium models of differentially rotating nascent neutron stars are constructed , which represent the result of the accretion induced collapse of rapidly rotating white dwarfs . the models are built in a two - step procedure : ( 1 ) a rapidly rotating pre - collapse white dwarf model is constructed ; ( 2 ) a stationary axisymmetric neutron star having the same total mass and angular momentum distribution as the white dwarf is constructed . the resulting collapsed objects consist of a high density central core of size roughly 20 km , surrounded by a massive accretion torus extending over 1000 km from the rotation axis . the ratio of the rotational kinetic energy to the gravitational potential energy of these neutron stars ranges from 0.13 to 0.26 , suggesting that some of these objects may have a non - axisymmetric dynamical instability that could emit a significant amount of gravitational radiation . = = = = = = = = # 1 # 1 # 1 # 1 @mathgroup@group @mathgroup@normal@groupeurmn @mathgroup@bold@groupeurbn @mathgroup@group @mathgroup@normal@groupmsamn @mathgroup@bold@groupmsamn = `` 019 = ' ' 016 = `` 040 = ' ' 336 = " 33e = = = = = = = = # 1 # 1 # 1 # 1 = = = = = = = = # 1 latexl-.36em.3ex-.15em t-.1667em.7ex-.125emx [ section ] [ firstpage ] stars : neutron stars : rotation stars : interiors white dwarfs instabilities . And you have already written the first three sentences of the full article: the accretion induced collapse of a rapidly rotating white dwarf can result in the formation of a rapidly and differentially rotating compact object . it has been suggested that such rapidly rotating objects could emit a substantial amount of gravitational radiation @xcite , which might be observable by the gravitational wave observatories such as ligo , virgo and geo . it has been demonstrated that if the collapse is axisymmetric , the energy emitted by gravitational waves is rather small @xcite .. Please generate the next two sentences of the article
however , if the collapsed object rotates rapidly enough to develop a non - axisymmetric ` bar ' instability , the total energy released by gravitational waves could be @xmath0 times greater than the axisymmetric case @xcite . rotational instabilities of rotating stars arise from non - axisymmetric perturbations of the form @xmath1 , where @xmath2 is the azimuthal angle .
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Suppose that you have an abstract for a scientific paper: the hard x - ray ( @xmath0-ray ) absorption by cylindrically symmetric @xmath1 test objects is studied by means of @xmath0-ray transmission measurements . to make a precise comparison between the theoretically modelled values and the absorption coefficients calculated from the experimental data , we have developed a highly accurate numerical code based on a new solution of abel s integral equation . it is shown that progressive filtering , surface reflections by compton scattering , and the enhanced backscattering due to impurities can explain much of the observed discrepancy . we also discuss optimal experimental conditions with regard to the feasibility of quantitative radiography for @xmath0-ray diagnostics . . And you have already written the first three sentences of the full article: the calculation of precise radial density profiles for a localized radiation source ( _ i.e. , _ soft x - ray emission by hot plasmas ) has been a long standing problem in both plasma physics and astrophysics @xcite . for a sufficiently tenuous plasma in which radiation emission processes dominate over absorption processes , the symmetric density profile of the plasma can be obtained from the projected radiation intensity by abel s inversion . another example of the application of abel s inversion is the determination of density profiles of an imploding spherical targets driven by laser - beams @xcite .. Please generate the next two sentences of the article
these two seemingly different diagnostic methods are mathematically identical and rely on the solutions of abel s integral equation @xcite . before proceeding further , it is important to point out that there have been extensive studies on the absorption of a soft x - ray by the abel s integral equation for medical applications by cormack @xcite who apparently was not aware of previous work on the x - ray diagnostics employed in astrophysics @xcite . despite numerous studies over many years @xcite ,
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Suppose that you have an abstract for a scientific paper: we study m5-branes compactified on @xmath0 from the d0-d4 witten index in the coulomb phase . we first show that the prepotential of this index is s - dual , up to a simple anomalous part . this is an extension of the well - known s - duality of the 4d @xmath1 theory to the 6d @xmath2 theory on finite @xmath3 . using this anomalous s - duality , we find that the asymptotic free energy scales like @xmath4 when various temperature - like parameters are large . this shows that the number of 5d kaluza - klein fields for light d0-brane bound states is proportional to @xmath4 . we also compute some part of the asymptotic free energy from 6d chiral anomalies , which precisely agrees with our d0-d4 calculus . addtoresetequationsection + * asymptotic m5-brane entropy from s - duality * seok kim and june nahmgoong _ department of physics and astronomy & center for theoretical physics + seoul national university , 1 gwanak - ro , gwanak - gu , seoul 08826 , korea . _ + e - mails : [email protected] , [email protected] . And you have already written the first three sentences of the full article: strong / weak - coupling duality , or s - duality , exists in a number of quantum systems . in 4d gauge theories , it takes the form of electromagnetic duality , which inverts the gauge coupling and exchanges the roles of elementary charged particles and magnetic monopoles @xcite . it is realized in the simplest manner in maximally supersymmetric yang - mills ( sym ) theory @xcite . in this case , the spectrum of dyons in the coulomb phase was shown to exhibit @xmath5 duality @xcite , providing a robust evidence of s - duality . s - duality in quantum field theories has also been a cornerstone of developing string dualities @xcite . in both qft and string theory ,. Please generate the next two sentences of the article
s - duality provides valuable insights on the strongly coupled regions of the systems . s - duality of maximal sym has many implications .
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Suppose that you have an abstract for a scientific paper: a chopper wheel construct is used to shorten the duration of a molecular beam to . molecular beams seeded with no or with br@xmath0 and an initial pulse width of @xmath1 @xmath2s were passed through a spinning chopper wheel , which was driven by a brushless dc _ in vacuo _ motor at a range of speeds , from to . the resulting duration of the molecular - beam pulses measured at the laser detection volume ranged from to , and was the same for both no and br@xmath0 . the duration is consistent with a simple analytical model , and the minimum pulse width measured is limited by the spreading of the beam between the chopper and the detection point as a consequence of the longitudinal velocity distribution of the beam . the setup adopted here effectively eliminates buildup of background gas without the use of a differential pumping stage , and a clean narrow pulse is obtained with low rotational temperature . . And you have already written the first three sentences of the full article: slow , velocity - controlled molecular beams have become an attractive tool in the study of molecular dynamics , the measurement of fundamental constants and in conducting high resolution spectroscopy @xcite . many advances have been made to produce slow beams such as using a high - pressure seeded expansion @xcite , pre - cooling from a buffer gas source @xcite , or by passing the gas through a cryo - cooled valve nozzle @xcite or a room - temperature nozzle spinning in a counter - rotating configuration @xcite . molecules in seeded supersonic beams can also be decelerated by undergoing inelastic collisions in a crossed beam set up to remove kinetic energy @xcite , or by using the interaction of the electric or magnetic dipole moments of the molecules with external optical dipole , electric , or magnetic fields @xcite .. Please generate the next two sentences of the article
many of these recent advances in the production of cold atomic and molecular beams would benefit from using the shortest gas pulse that is compatible with maintaining a high number density , narrow velocity distribution and cold rotational distribution . very short pulsed beams produce fewer gas molecules in the vacuum chamber , thereby lowering the gas load on the pumps for the experimental apparatus , and reducing background collisions with the beam ; the low velocity spread and cold internal temperature of the molecules in the beam are thus preserved @xcite .
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Suppose that you have an abstract for a scientific paper: we have selected and analysed the properties of a sample of 2905 @xmath0 galaxies in @xmath1 of the great observatories origins deep survey ( goods ) chandra deep field south ( cdfs ) , to obtain further constraints on the evolution of @xmath2-selected galaxies with respect to the results already obtained in previous studies . we made use of the public deep multiwavelength imaging from the optical @xmath3 through the infrared ( ir ) @xmath4 bands , in conjunction with available spectroscopic and combo17 data in the cdfs , to construct an optimised redshift catalogue for our galaxy sample . we computed the @xmath2-band lf and determined that its characteristic magnitude has a substantial brightening and a decreasing total density from @xmath5 to @xmath6 . we also analysed the colours and number density evolution of galaxies with different stellar masses . within our sample , and in contrast to what is observed for less massive systems , the vast majority ( @xmath7% ) of the most massive ( @xmath8 ) local galaxies appear to be in place before redshift @xmath9 . around @xmath10% of the total assemble between redshifts @xmath11 and @xmath12 and most of them display extremely red colours , suggesting that plausible star formation in these very massive systems should mainly proceed in obscured , short - timescale bursts . the remaining fraction ( up to @xmath13% ) could be in place at even higher redshifts @xmath14 , pushing the first epoch of formation of massive galaxies beyond the limits of current near - ir surveys . [ firstpage ] galaxies : evolution galaxies : formation galaxies : high - redshift galaxies : luminosity function , mass function . And you have already written the first three sentences of the full article: deep multiwavelength surveys are progressively sheding light on the history of galaxy evolution since very high redshifts . from new surveys in the ultraviolet regime ( e.g. martin et al . 2005 ) to the latest ir , sub - millimetre and radio campaigns ( e.g. werner et al . 2004 ; dunlop 2005 ; condon et al . 2003 ) , the advent of numerous datasets is enhancing our understanding of when galaxies were formed and how they evolved through cosmic time . uv / optical observations can unveil the sources of stellar emission but are limited to detect unobscured systems , missing an important fraction of the galaxies with on - going star formation .. Please generate the next two sentences of the article
ir and longer - wavelength surveys provide an unbiased way of studying star - forming systems , but are insensitive to galaxies with little or no dust content . near - ir observations , on the contrary , appear as one of the most suitable methods for making a complete census of galaxy populations , as they are sensitive to the stellar emission from both young and old galaxies , and are also relatively unaffected by the presence of dust .
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Suppose that you have an abstract for a scientific paper: we theoretically study the frequency stability of an opto - mechanical radio frequency oscillator based on resonant interaction of two optical and one mechanical modes of the same optical microcavity . a generalized expression for the phase noise of the oscillator is derived using langevin formalism and compared to the phase noise of existing electronic oscillators . . And you have already written the first three sentences of the full article: the opto - mechanical oscillator ( omo ) generates spectrally pure radio frequency ( rf ) signals @xcite due to ponderomotive interaction between photons and phonons . phase noise and linewidth are the main characteristics detremining the performance of an oscillator and its practical usefulness . it was shown that the omo linewidth can be small enough to be ultimately described by a schawlow - townes - like formula @xcite . a leeson model @xcite of the phase noise far from the carrierfor a radiation pressure driven omo was presented in @xcite . in this paper. Please generate the next two sentences of the article
we derive a generalized formula for the omo phase noise that takes into account the noise of the light pumping the resonator . using the formula , we analyze allan deviation of the oscillator frequency as well as its linewidth . the predicted performance of the omo
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Suppose that you have an abstract for a scientific paper: we show that the lawrence krammer representation is unitary . we explicitly present the non - singular matrix representing the sesquilinear pairing invariant under the action . we show that reversing the orientation of a braid is equivalent to the transposition of its lawrence krammer matrix followed by a certain conjugation . as corollaries it is shown that the characteristic polynomial of the lawrence krammer matrix is invariant under substitution of its variables with their inverses up to multiplication by units , and is not a complete conjugacy invariant for braids . . And you have already written the first three sentences of the full article: the lawrence krammer representation @xmath0 , n(n-1)/2)$ ] was first introduced by lawrence @xcite and proved to be faithful by bigelow @xcite and krammer @xcite . as a braid invariant @xmath1 is strong enough to distinguish all braids . the characteristic polynomial @xmath2 , where @xmath3 denotes the @xmath4 dimensional identity matrix , of the lawrence. Please generate the next two sentences of the article
krammer matrix @xmath5 of a braid @xmath6 appears to be rather good as a conjugacy invariant of braids . the author observed that @xmath7 does not detect the orientation reversal of strings of braids , hence is not a complete conjugacy invariant , and that the polynomial @xmath8 has a symmetry @xmath9 just like the alexander polynomial of links ( see corollary [ coro : incomplete ] and [ coro : rev ] ) .
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Suppose that you have an abstract for a scientific paper: in this paper , we develop new methods for estimating average treatment effects in observational studies , in settings with more than two treatment levels , assuming unconfoundedness given pre - treatment variables . we emphasize propensity score subclassification and matching methods which have been among the most popular methods in the binary treatment literature . whereas the literature has suggested that these particular propensity - based methods do not naturally extend to the multi - level treatment case , we show , using the concept of weak unconfoundedness and the notion of the generalized propensity score , that adjusting for a scalar function of the pre - treatment variables removes all biases associated with observed pre - treatment variables . we apply the proposed methods to an analysis of the effect of treatments for fibromyalgia . we also carry out a simulation study to assess the finite sample performance of the methods relative to previously proposed methods . keywords : generalized propensity score ; matching ; multi - level treatments ; potential outcomes ; subclassification ; unconfoundedness . . And you have already written the first three sentences of the full article: there is an extensive theoretical and empirical literature on estimating average causal effects of binary treatments in observational studies based on the assumption of unconfoundedness or ignorable treatment assignment . under this assumption differences in outcomes for units with different treatment levels , but the same values for pre - treatment variables , can be interpreted as estimates of causal effects . much of the literature builds on the seminal paper by @xcite ( rr83 from here on ) which clarified the central role of the propensity score ( the conditional probability of receiving the treatment given the pre - treatment variables or covariates ) in analyses of causal effects in such settings , and which proposed a number of widely used estimators . see @xcite for a textbook treatment .. Please generate the next two sentences of the article
although important for empirical practice , much less theoretical work has been done on the setting with more than two treatment levels ( exceptions include @xcite ; @xcite ; @xcite ) . because in settings with multi - level treatments there is no scalar function of the covariates that has all the properties that rr83 presents for the propensity score in the binary treatment case , it has been claimed that there is no natural analogue to matching and subclassification on the propensity score ( @xcite ) . in the main contribution of the current paper we show that , contrary to these claims , the essence of the results in rr83 generalizes to the setting with multi - level treatments .
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Suppose that you have an abstract for a scientific paper: i summarize the status of three neutrino oscillations that follow from combining the relevant world s data . the discussion includes the small parameters @xmath0 and @xmath1 , which characterize the strength of cp violation in neutrino oscillations , the impact of oscillation data on the prospects for probing the absolute scale of neutrino mass in and the robustness of the neutrino oscillation interpretation itself in the presence of non - standard physics . i also comment on the theoretical origin of neutrino mass , mentioning recent attemps to explain current oscillation data . address= ahep group , instituto de fsica corpuscular , c.s.i.c . universitat de valncia + edificio de institutos de paterna , apartado 22085 , e46071 valncia , spain + . And you have already written the first three sentences of the full article: the discovery of neutrino oscillations has marked a turning point in our understanding of nature and has brought neutrino physics to the center of attention of the particle , nuclear and astrophysics communities . here i summarize the determination of neutrino mass and mixing parameters in neutrino oscillation studies following ref . @xcite to which the reader is referred for details on data analysis and experimental references . for future neutrino oscillation projects. Please generate the next two sentences of the article
see ref . the structure of the three - flavour lepton mixing matrix in various gauge theories of neutrino mass was given in @xcite .
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Suppose that you have an abstract for a scientific paper: non - orthogonal multiple access ( noma ) has recently been considered as a key enabling technique for 5 g cellular systems . in noma , by exploiting the channel gain differences multiple users are multiplexed into transmission power domain and then non - orthogonally scheduled on the same spectrum resources . successive interference cancellation ( sic ) is then applied at the receiver(s ) to decode the message signals . in this paper , first we briefly describe the differences in the working principles of uplink and downlink noma transmissions . then , for both uplink and downlink noma , we formulate a sum - throughput maximization problem in a cell such that the user clustering ( i.e. , grouping users into a single cluster or multiple clusters ) and power allocations in noma cluster(s ) can be optimized under transmission power constraints , minimum rate requirements of the users , and sic constraints . due to the combinatorial nature of the formulated mixed integer non - linear programming ( minlp ) problem , we solve the problem in two steps , i.e. , by first grouping users into clusters and then optimizing their respective power allocations . in particular , we propose a low - complexity sub - optimal user grouping scheme . the proposed scheme exploits the channel gain differences among users in a noma cluster and group them into a single cluster or multiple clusters in order to enhance the sum - throughput of the system . for a given set of noma clusters , we then derive the optimal power allocation policy that maximizes the sum throughput per noma cluster and in turn maximizes the overall system throughput . using kkt optimality conditions , closed - form solutions for optimal power allocations are derived for any cluster size , considering both uplink and downlink noma systems . numerical results compare the performance of noma over orthogonal multiple access ( oma ) and illustrate the significance of noma in various network scenarios . 5 g cellular , non - orthogonal multiple.... And you have already written the first three sentences of the full article: recently , non - orthogonal multiple access ( noma ) @xcite has been considered as a promising technique for fifth generation ( 5 g ) and beyond 5 g ( b5 g ) cellular networks . the key idea of noma is to simultaneously serve multiple users ( ideally all active users in a serving cell ) over same radio resources at the expense of minimal inter - user interference . noma not only allows serving individual users with higher effective bandwidth but also allows scheduling more users than the number of available resources .. Please generate the next two sentences of the article
in contrast to conventional orthogonal multiple access ( oma ) , where every user is served on exclusively allocated radio resources , noma superposes the message signals of multiple users in power domain by exploiting their respective channel gain differences . successive interference cancellation ( sic ) is then applied at the receivers for multi - user detection and decoding . for example , in downlink noma , the base station ( bs ) schedules different users over same resources but their respective message signals are transmitted using different power levels . by exploiting the power differences , each user equipment ( ue ) can apply sic and in turn decode its desired signal . recently , numerous research activities have been initiated across the globe to identify the potential gains of noma in both the downlink and uplink transmissions . here
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Suppose that you have an abstract for a scientific paper: we experimentally study a system of quantum kicked rotors - an ensemble of diatomic molecules exposed to a periodic sequence of ultrashort laser pulses . in the regime , where the underlying classical dynamics is chaotic , we investigate the quantum phenomenon of dynamical localization by means of state - resolved coherent raman spectroscopy . we examine the dependence of the exponentially localized angular momentum distribution and of the total rotational energy on the time period between the pulses and their amplitude . the former parameter is shown to provide control over the localization center , whereas the latter one controls the localization length . similar control of the center and width of a nonlocalized rotational distribution is demonstrated in the limit of classical diffusion , established by adding noise to the periodic pulse sequence . . And you have already written the first three sentences of the full article: the periodically kicked rotor is one of the simplest systems whose classical motion exhibits chaotic dynamics , leading to an unbounded diffusive growth of its energy with the number of kicks . in contrast , the energy growth of a quantum kicked rotor ( qkr ) is determined by the interference of quantum interaction pathways @xcite . in the quantum limit , the rotational excitation is either enhanced due to quantum resonances @xcite or suppressed due to the effect of dynamical localization @xcite , which has been linked to anderson localization in solids @xcite .. Please generate the next two sentences of the article
similarly to the localization of a quantum particle in a disordered one - dimensional lattice , the qkr localizes in a `` rotational lattice '' of angular momentum states . experimental work has mostly been conducted in substitute systems , imitating the qkr behavior with rydberg atoms in microwave fields @xcite or ultracold atoms in optical lattices @xcite . in a series of recent articles @xcite ,
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Suppose that you have an abstract for a scientific paper: extended emission gamma - ray bursts are a subset of the ` short ' class of burst which exhibit an early time rebrightening of gamma emission in their light curves . this extended emission arises just after the initial emission spike , and can persist for up to hundreds of seconds after trigger . when their light curves are overlaid , our sample of 14 extended emission bursts show a remarkable uniformity in their evolution , strongly suggesting a common central engine powering the emission . one potential central engine capable of this is a highly magnetized , rapidly rotating neutron star , known as a magnetar . magnetars can be formed by two compact objects coallescing , a scenario which is one of the leading progenitor models for short bursts in general . assuming a magnetar is formed , we gain a value for the magnetic field and late time spin period for 9 of the extended emission bursts by fitting the magnetic dipole spin - down model of @xcite . assuming the magnetic field is constant , and the observed energy release during extended emission is entirely due to the spin - down of this magnetar , we then derive the spin period at birth for the sample . we find all birth spin periods are in good agreement with those predicted for a newly born magnetar . [ firstpage ] general gamma rays : bursts . . And you have already written the first three sentences of the full article: gamma - ray bursts ( grbs ) are the brightest phenomena in the universe , releasing as much electromagnetic energy in tens of seconds as the entire milky way galaxy does in a few years @xcite . they typically reach energies of around 5 x 10@xmath0 ergs when beaming is accounted for @xcite . their temporal distribution shows a bimodality @xcite which separates them into ` long ' or ` short ' grbs ( lgrb and sgrb respectively ) depending on a parameter known as t@xmath1 ; the time in which 90% of the gamma - ray fluence is detected .. Please generate the next two sentences of the article
nominally , long bursts have t@xmath2 seconds , and short ones have t@xmath3 seconds , but in reality the distinction is far more blurred for a significant number of cases ( eg @xcite ; @xcite ; @xcite ) . both classes have been observed to be distributed isotropically across the sky @xcite .
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Suppose that you have an abstract for a scientific paper: we have analyzed the archival data of fuv observations for the region of gsh 006 - 15 + 7 , a large shell - like structure discovered by @xcite from the velocity maps . fuv emission is seen to be enhanced in the lower supershell region . the fuv emission is considered to come mainly from the scattering of interstellar photons by dust grains . a corresponding monte carlo simulation indicates that the distance to the supershell is 1300 @xmath0 800 pc , which is similar to the previous estimation of 1500 @xmath0 500 pc based on kinematic considerations . the spectrum at lower galactic latitudes of the supershell exhibits molecular hydrogen fluorescence lines ; a simulation model for this candidate photodissociation region ( pdr ) yields an h@xmath1 column density of n(h@xmath1 ) = 10@xmath2 @xmath3 with a rather high total hydrogen density of n@xmath4 @xmath5 30 @xmath6 . . And you have already written the first three sentences of the full article: supershells are giant bubbles with a scale of hundreds of parsecs , and are believed to be created by multiple stellar winds from ob associations and supernova explosions @xcite . supershells play an important role in galaxy evolution since they redistribute huge amounts of energy and material from the galaxy disc to the galaxy halo . the interstellar matter swept up by supershells forms cold and dense regions in which new star formation is triggered .. Please generate the next two sentences of the article
the typical lifetime of supershells is about 10@xmath7 years @xcite , much longer than those of supernova remnants ( snrs ; * ? ? ? supershells have been found with observations of 21-cm line emission originating from the cold and dense shells @xcite , in which infrared emission associated with dust is also observed . for younger supershells ,
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Suppose that you have an abstract for a scientific paper: we present @xmath0-ray spectra for a set of type ia supernovae models . our study is based on a detailed monte carlo transport scheme for both spherical and full 3-d geometries . classical and new challenges of the @xmath0 ray astronomy are addressed . we find that @xmath0-rays are very suitable to reveal the structure of the envelope and , thus , they allow to probe properties of the nuclear burning front and the progenitor , namely its central density and global asphericities . the potential problems are discussed for the quantitative comparison between theoretical and observed line fluxes during the first few months after the explosion . . And you have already written the first three sentences of the full article: @xmath1-ray observations have long been recognized as a potential , valuable tool for supernovae research @xcite . only @xmath1-rays provide a direct link to the ni distribution which hardly depends on details of the physics and on the numerical treatment . different scenarios can be distinguished by line fluxes and profiles , the structure of the progenitors can be probed , and the time of the explosion can be determined .. Please generate the next two sentences of the article
@xmath0-rays can provide a good determination of the @xmath2 production for nearby sne ia because , nowadays , accurate distances of nearby galaxies can be obtained by @xmath3ceph . moreover , all sky surveys by @xmath0-rays may provide an unbiased rate of sne ia . as we will discuss below
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Suppose that you have an abstract for a scientific paper: a gauged @xmath0 symmetry predicts three right handed handed neutrinos and its spontaneous breaking automatically yields the seesaw mechanism . in a supersymmetric setting this breaking can be nicely linked with inflation to yield @xmath1 proportional to @xmath2 , where @xmath3 @xmath4 denote the @xmath5 breaking ( planck ) scale . thus @xmath3 is estimated to be of order @xmath6 gev , and the heaviest right handed neutrino mass is less than or of order @xmath7 gev . a second right handed neutrino turns out to have a mass of order @xmath8 , where @xmath9 ( @xmath10 gev ) denotes the reheat temperature . a @xmath11 r symmetry plays an essential role in implementing inflation and leptogenesis , resolving the mssm @xmath12 problem and eliminating dimension five nucleon decay . an unbroken @xmath13 subgroup plays the role of matter parity . the scalar spectral index @xmath14 for the simplest models , while in smooth hybrid inflation @xmath15 . the tensor to scalar ratio @xmath16 is negligible , and @xmath17 . . And you have already written the first three sentences of the full article: physics beyond the standard model ( sm ) is required by the following experimental observations : * neutrino oscillations : @xmath18 ( mass difference)@xmath19 needed to understand atmospheric and solar neutrino observations ; * cmb anisotropy ( @xmath20 ) : requires inflation which can not be realized in the sm ; * non - baryonic dark matter ( @xmath21 ) : sm has no plausible candidate ; * baryon asymmetry ( @xmath22 ) : not possible to achieve in the sm . recall that at the renormalizable level the sm possesses a global @xmath0 symmetry . if the symmetry is gauged , the anomaly cancellation requires the existence of three right handed neutrinos . an important question therefore is the symmetry breaking scale of @xmath0 .. Please generate the next two sentences of the article
note that this scale is not fixed by the evolution of the three sm gauge couplings . remarkably , we will be able to determine the @xmath3 by implementing inflation . with @xmath3 well below the planck scale the seesaw mechanism enables us to realize light neutrino masses in the desired range .
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Suppose that you have an abstract for a scientific paper: a modelgenerator is developed that searches for cointegrated models among a potentially large group of candidate models . the generator employs the first step of the engle - granger procedure and orders cointegrated models according to the information criterions aic and bic . assisted by the generator , a cointegrated relation is established between recorded violent crime in the netherlands , the number of males aged 15 - 25 years ( split into western and non - western background ) and deflated consumption . in - sample forecasts reveal that the cointegrated model outperforms the best short - run models . . And you have already written the first three sentences of the full article: the statistical relation between recorded crime and economic and demographic variables , such as unemployment and the number of young males , is not only of fundamental importance @xcite , but becomes increasingly important in forecasting tools for policy and planning decisions @xcite . as recorded crime and its predictor variables are generally integrated of order one , two kinds of models exist . there are short - run models specified in first differences and cointegrated models specified in levels . in a short - run model , crime has a strong stochastic dynamic of its own , eventually drifting away uncontrollably from the relation with its predictors .. Please generate the next two sentences of the article
conversely , in a cointegrated model , crime fluctuates with constant variability around the relation with its predictors , thereby preserving its importance in the long run . as a consequence , cointegrated models are to be favored over short - run models when making long term forecasts . theoretically , given a set of predictor variables
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Suppose that you have an abstract for a scientific paper: to study the localization of random heteropolymers at an interface separating two selective solvents within the model of garel , huse , leibler and orland , europhys . lett . * 8 * 9 ( 1989 ) , we propose a disorder - dependent real space renormalization approach . this approach allows to recover that a chain with a symmetric distribution in hydrophobic / hydrophilic components is localized at any temperature in the thermodynamic limit , whereas a dissymmetric distribution in hydrophobic / hydrophilic components leads to a delocalization phase transition . it yields in addition explicit expressions for thermodynamic quantities as well as a very detailed description of the statistical properties of the heteropolymer conformations in the high temperature limit . in particular , scaling distributions are given for the lengths of the blobs in each solvent , for the polymer density , and for some correlation functions . in the case of a small dissymmetry in hydrophobic / hydrophilic components , the renormalization approach yields explicit expressions for the delocalization transition temperature and for the critical behaviors of various quantities : in particular , the free energy presents an essential singularity at the transition ( the transition is thus of infinite order ) , the typical length of blobs in the preferred solvent diverges with an essential singularity , whereas the typical length of blobs in the other solvent diverges algebraically . finite - size properties are also characterized in details in both cases . in particular , we give the probability distribution of the delocalization temperature for the ensemble of random chains of finite ( large ) length @xmath0 , and the distribution of the numbers of blobs for the chains that are still localized at a given temperature . finally , we discuss the non - equilibrium dynamics at temperature @xmath1 starting from a zero - temperature initial condition . epsf 1.5 cm -0.5 cm . And you have already written the first three sentences of the full article: among the various subjects concerning the physics of polymers , the behavior of heteropolymers containing hydrophobic and hydrophilic components in solvents are of particular interest since they have obvious importance in biology @xcite . it is well known for instance that in a polar solvent , these heteropolymers prefer conformations where the hydrophilic components are in contact with the polar solvent , whereas hydrophobic components avoid contacts with the solvent . the behavior of heteropolymers in the presence of an interface separating two selective solvents , one favorable to the hydrophobic components and the other to the hydrophilic components , is less obvious , and has been much studied recently . in the pioneering work of garel , huse , leibler and orland @xcite , a model was proposed and studied via imry - ma arguments , an analysis of the replica hamiltonian and numerics : it was found that a chain with a symmetric distribution in hydrophobic / hydrophilic components is always localized around the interface at any temperature ( in the thermodynamic limit ) , whereas a chain with a dissymmetric distribution in hydrophobic / hydrophilic components presents a phase transition separating a localized phase at low temperatures from a delocalized phase into the most favorable solvent at high temperatures .. Please generate the next two sentences of the article
experimentally , the presence of copolymers was found to stabilize the interface between the two immiscible solvents @xcite , since the localization of the heteropolymers at the interface reduces the surface tension . by now , the predictions of reference @xcite have been confirmed in the physics community by various approaches including molecular dynamics simulations @xcite , monte carlo studies @xcite , variational methods for the replica hamiltonian @xcite @xcite , and exact bounds for the free - energy @xcite . mathematicians have also been interested in this model , but the exact results obtained up to now are still far from a complete explicit solution .
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Suppose that you have an abstract for a scientific paper: relativistic solitons are self - trapped , finite size , electromagnetic waves of relativistic intensity that propagate without diffraction spreading . they have been predicted theoretically within the relativistic fluid approximation , and have been observed in multi dimensional particle in cell simulations of laser pulse interaction with the plasma . solitons were observed in the laser irradiated plasmas with the proton imaging technique as well . this paper reviews many theoretical results on relativistic solitons in electron ion plasmas . . And you have already written the first three sentences of the full article: relativistic solitons are self trapped , finite size , electromagnetic waves of relativistic intensity @xmath0 that propagate without diffraction spreading . many different physical effects play a role in the formation of relativistic solitons : dispersion effects due to the finite particle inertia , nonlinearities due to relativistic mass increase , as well as ponderomotive effects which force the plasma density redistribution . the theoretical investigation of relativistic solitons in electron ion plasmas is a relatively old problem in plasma physics , which has been treated by many authors in the past , and has recently gained new attention in the literature @xcite .. Please generate the next two sentences of the article
the analyses have been performed mainly in the framework of the 1d relativistic fluid approximation , in which solitons are described by the solutions of a set of coupled nonlinear differential equations for the electrostatic and electromagnetic potentials with suitable boundary conditions . relativistic solitons have been seen in multi - dimensional particle in cell ( pic ) as well as in fluid simulations of laser pulse interaction with the plasma @xcite .
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Suppose that you have an abstract for a scientific paper: several controversial issues concerning the packing of linear dna in bacteriophages and globules are discussed . exact relations for the osmotic pressure , capsid pressure and loading force are derived in terms of the hole size inside phages under the assumption that the dna globule has a uniform density . a new electrostatic model is introduced for computing the osmotic pressure of rodlike polyelectrolytes at very high concentrations . at intermediate packing , a reptation model is considered for dna diffusing within a toroidal globule . under tight packing conditions , a model of coulomb sliding friction is proposed . a general discussion is given of our current understanding of the statics and dynamics of confined dna in the context of to the following experiments : characterization of the liquid crystalline phases , x - ray scattering by phages , osmotic stress measurements , cyclization within globules and single - molecule determination of the loading forces . . And you have already written the first three sentences of the full article: the compaction of dna in biological cells and viruses presents us with rather unconventional problems in the physics of soft matter . in the case of phages or viruses , the dna may be so close - packed that the thermodynamics is no longer extensive because it is dominated by the energy arising from regions of tight bending ( odijk 1998 ) . thus we are dealing with a defect rather than a bulk system . confronting the mathematical physics of the dna configurations as. Please generate the next two sentences of the article
such is a formidable undertaking . still , the condensed dna globule ought to have relatively minor fluctuations in the density ( ubbink & odijk 1996 ) so that simplified analyses are possible .
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Suppose that you have an abstract for a scientific paper: effects of magnetic field on stellar differential rotation are studied by comparing magnetohydrodynamic ( mhd ) models and their hydrodynamic ( hd ) counterparts in the broad range of rotation rate and in varying initial rotation profile . fully - compressible mhd simulations of rotating penetrative convection are performed in a full - spherical shell geometry . critical conditions for the transition of the differential rotation between faster equator ( solar - type ) and slower equator ( anti - solar type ) are explored with focusing on the rossby number ( @xmath0 ) " and the convective rossby number ( @xmath1 ) " . it is confirmed that the transition is more gradual and the critical value for it is higher in the mhd model than the hd model in the view of the @xmath1-dependence . the rotation profile shows , as observed in earlier studies , the bistability near the transition in the hd model , while it disappears when allowing the growth of magnetic fields except for the model with taking anti - solar type solution as the initial condition . we find that the transition occurs at @xmath2 both in the mhd and hd models independently of the hysteresis . not only the critical value , the sharpness of the transition is also similar between the two models in the view of the @xmath0-dependence . the influences of the dynamo - generated magnetic field and/or the hysteresis on convective motion are reflected in the @xmath0 . this would be the reason why the transition is unified in the view of the @xmath0-dependence . we finally discuss the @xmath0-dependence of magnetic dynamo activities with emphasis on its possible relation to the kinetic helicity profile . . And you have already written the first three sentences of the full article: the differential rotation ( dr ) is believed to be a key ingredient in organizing large - scale magnetic fields in the solar interior . most of standard solar dynamo scenarios rely heavily on , so - called @xmath3-effect as the amplification process of magnetic fields to reproduce observed solar magnetic activity with cyclic polarity reversals and butterfly - shaped spatiotemporal migrations ( see , e.g. , * ? ? ? * ; * ? ? ?. Please generate the next two sentences of the article
* for reviews ) . however , we have not yet arrived at a full understanding of the physical mechanism for maintaining the solar differential rotation .
10,870
Suppose that you have an abstract for a scientific paper: using first - principles calculations , we study the magnetism of @xmath0 transition - metal atomic junctions including structural relaxations and spin - orbit coupling . upon stretching monatomic chains of w , ir , and pt suspended between two leads , we find the development of strong magnetism and large values of the magnetocrystalline anisotropy energy ( mae ) of up to 30 mev per chain atom . we predict that switches of the easy magnetization axis of the nanocontacts upon elongation should be observable by ballistic anisotropic magnetoresistance measurements . due to the different local symmetry , the contributions to the mae of the central chain atoms and chain atoms in the vicinity of the leads can have opposite signs which reduces the total mae . we demonstrate that this effect occurs independent of the chain length or geometry of the electrodes . . And you have already written the first three sentences of the full article: fascinating insights into the formation of atomic chains consisting only of a few atoms suspended between two electrodes have been obtained by transmission electron microscopy and mechanically controllable break junction techniques.@xcite these experiments triggered the imagination of scientists to use such atomic - scale junctions as future electronic devices by exploiting their unique properties , e.g. ballistic electronic transport.@xcite due to their reduced dimensions , atomic chains have also been predicted to develop magnetic moments even for elements nonmagnetic in bulk such as ir , pt , or pd.@xcite recently , an indirect proof has been given that transition - metal chains in break junctions are in general magnetic.@xcite mastering the intriguing magnetic properties of suspended chains would enable spintronic applications based on the unique possibility to probe , control and switch the magnetic states by spin - polarized currents.@xcite the orientation of the magnetic moments is stabilized against thermal fluctuations by the magnetocrystalline anisotropy energy ( mae ) arising from spin - orbit coupling . theoretical studies of this key quantity performed for idealized systems such as free - standing infinite monowires ( mws ) and small clusters suggest giant values for @xmath1- and @xmath0-transition - metals and switching of the easy axis upon stretching the wires . @xcite even the size of the magnetic moment itself can crucially depend on the magnetization direction , an effect coined as colossal magnetic anisotropy.@xcite the ballistic conductance in such wires varies with the orientation of the magnetization direction with respect to the chain axis giving rise to ballistic anisotropic magnetoresistance ( bamr).@xcite while the predicted effects probably occur in real atomic - scale junctions , the theoretical studies have either focused on idealized systems or neglected varying interatomic distances in the chains.@xcite however , for small suspended chains variations in the interatomic.... Please generate the next two sentences of the article
we perform first - principles calculations for w , ir and pt junctions including spin - orbit coupling and structural relaxations and focus on atomic chains of three atoms suspended between two bulk - like bcc-(001 ) electrodes as shown in fig . these transition - metals are common tip materials in scanning tunneling microscopy , and ir and pt have been shown to form long atomic chains in break junction experiments.@xcite in particular we concentrate on the influence of varying tip - to - tip separation on the magnetic properties of the junctions .
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Suppose that you have an abstract for a scientific paper: we discuss the euv and x - ray properties of b stars , focusing on ( b2 ii ) which is the _ only _ star with both emission lines and a photospheric continuum detected with . we explore the modest effects of the photospheric euv continua on the wind , as well as the much stronger effects of the short - wavelength euv and soft x - ray emission lines . attenuation of the euv and soft x - ray emission by the wind plays an important role , and leads to the reprocessing of x - rays via he@xmath0 ionization and the bowen mechanism in the wind . finally , we explore some of the new diagnostics that will shortly become available with the next generation of high spectral resolution x - ray telescopes . all of this analysis is presented in the context of a two component stellar wind a dense component ( clumps ) that contains most of the mass but fills a negligible fraction of the volume , and a rarefied component that fills most of the volume but accounts for only a small fraction of the mass . # 1#2#1@xmath1#2 . And you have already written the first three sentences of the full article: the primary differences between the winds of b stars and those of o stars are the much lower densities of b star winds and the relative importance of euv / x - ray emission in b stars . in this paper we will examine the ionization and temperature structure of b star winds , with a focus on the euv and x - ray emission properties of these objects . we will see how the differences in the wind and euv / x - ray properties cause strong departures from the thermal and ionization conditions found in the more well - studied and well - understood o stars . the ionization balance in b star winds is both more complex , and harder to determine , both theoretically and observationally , than in o star winds .. Please generate the next two sentences of the article
in fact , because of the more uncertain ionization corrections to the uv mass - loss rates the actual mass - loss rates of b stars are not well known . in addition to this crucial difference between the high wind densities of o stars and the low wind densities of b stars , the relative proximity of the nearest b stars provides us with some important information that does not exist for o stars . due to the very low column densities toward @xmath2 cma and @xmath3 cma
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Suppose that you have an abstract for a scientific paper: in this paper , we associate to every @xmath0-adic representation @xmath1 a @xmath0-adic differential equation @xmath2 , that is to say a module with a connection over the robba ring . we do this via the theory of fontaine s @xmath3-modules . this construction enables us to relate the theory of @xmath3-modules to @xmath0-adic hodge theory . we explain how to construct @xmath4 and @xmath5 from @xmath2 , which allows us to recognize semi - stable or crystalline representations ; the connection is then either unipotent or trivial on @xmath6 $ ] . in general , the connection has an infinite number of regular singularities , but we show that @xmath1 is de rham if and only if those are apparent singularities . a structure theorem for modules over the robba ring allows us to get rid of all singularities at once , and to obtain a `` classical '' differential equation , with a frobenius structure . a recent theorem of y. andr gives a complete description of the structure of such an object . this allows us to prove fontaine s @xmath0-adic monodromy conjecture : every de rham representation is potentially semi - stable . as an application , we can extend to the case of arbitrary perfect residue fields some results of hyodo ( @xmath7 ) , of perrin - riou ( the semi - stability of ordinary representations ) , of colmez ( absolutely crystalline representations are of finite height ) , and of bloch and kato ( if the weights of @xmath1 are @xmath8 , then bloch - kato s exponential @xmath9 is an isomorphism ) . . And you have already written the first three sentences of the full article: introduction \1 . rappels et notations \2 . les anneaux @xmath10 et @xmath11 \3 .. Please generate the next two sentences of the article
application aux reprsentations @xmath0-adiques \4 . proprits de @xmath12 \5 . structures diffrentielles sur les @xmath3-modules et monodromie @xmath0-adique \6 .
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Suppose that you have an abstract for a scientific paper: we analyze the relationships between atomic , neutral hydrogen ( ) and star formation ( sf ) in the 12 low - mass shield galaxies . we compare high spectral ( @xmath00.82kms@xmath1ch@xmath1 ) and spatial resolution ( physical resolutions of 170pc700pc ) imaging from the vla with h@xmath2 and far - ultraviolet imaging . we quantify the degree of co - spatiality between star forming regions and regions of high column densities . we calculate the global star formation efficiencies ( sfe , @xmath3/@xmath4 ) , and examine the relationships among the sfe and mass , column density , and star formation rate ( sfr ) . the systems are consuming their cold neutral gas on timescales of order a few gyr . while we derive an index for the kennicutt - schmidt relation of @[email protected]@xmath70.04 for the shield sample as a whole , the values of @xmath5 vary considerably from system to system . by supplementing shield results with those from other surveys , we find that hi mass and uv - based sfr are strongly correlated over five orders of magnitude . identification of patterns within the shield sample allows us to bin the galaxies into three general categories : 1 ) mainly co - spatial and sf regions , found in systems with highest peak column densities and highest total masses ; 2 ) moderately correlated and sf regions , found in systems with moderate column densities ; and 3 ) obvious offsets between and sf peaks , found in systems with the lowest total masses . sf in these galaxies is dominated by stochasticity and random fluctuations in their ism . . And you have already written the first three sentences of the full article: the conversion of gas into stars is one of the most fundamental processes in astronomy . yet , despite decades of effort , a simple prescription of star formation ( sf ) that successfully describes all observations of galaxies across a range of halo masses has remained elusive . in broad terms , more massive star - forming galaxies will have larger gas reservoirs ( both atomic and molecular ) and higher global star formation rates ( sfr ) than less massive systems ( see , e.g. , * ? ? ? however , the gas mass fractions in star forming galaxies tend to increase with decreasing mass ( e.g. , * ? ? ? * ) . empirical correlations between gas properties and various tracers of instantaneous (. Please generate the next two sentences of the article
using h@xmath2 emission , with a characteristic timescale of @xmath8 10 myr ) or ongoing ( using fuv emission , with a characteristic timescale of @xmath8 100 myr ) sf have been numerous in the literature . the most common parameterization relates a sfr surface density to a gas surface density : @xmath9 with the sfr surface density ( @xmath10 ) in units of m@xmath11yr@xmath1kpc@xmath12 , the gas surface density ( @xmath13 ) in units of m@xmath11pc@xmath12 , and @xmath5 being a positive number .
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Suppose that you have an abstract for a scientific paper: we present the results of near - infrared multi - object spectroscopic observations for 37 @xmath0-color - selected star - forming galaxies conducted with moircs on the subaru telescope . the sample is drawn from the @xmath1-band selected catalog of the moircs deep survey ( mods ) in the goods - n region . about half of our samples are selected from the publicly available 24@xmath2m - source catalog of the multiband imaging photometer for _ spitzer _ on board the _ spitzer space telescope_. h@xmath3 emission lines are detected from 23 galaxies , of which the median redshift is 2.12 . we derived the star formation rates ( sfrs ) from extinction - corrected h@xmath3 luminosities . the extinction correction is estimated from the sed fitting of multi - band photometric data covering uv to near - infrared wavelengths . the balmer decrement of the stacked emission lines shows that the amount of extinction for the ionized gas is larger than that for the stellar continuum . from a comparison of the extinction corrected h@xmath3 luminosity and other sfr indicators we found that the relation between the dust properties of stellar continuum and ionized gas is different depending on the intrinsic sfr ( differential extinction ) . we compared sfrs estimated from extinction corrected h@xmath3 luminosities with stellar masses estimated from sed fitting . the comparison shows no correlation between sfr and stellar mass . some galaxies with stellar mass smaller than @xmath4 show sfrs higher than @xmath5 . the specific sfrs ( ssfrs ) of these galaxies are remarkably high ; galaxies which have ssfr higher than @xmath6 are found in 8 of the present sample . from the best - fit parameters of sed fitting for these high ssfr galaxies , we find that the average age of the stellar population is younger than 100myr , which is consistent with the implied high ssfr . the large sfr implies the possibility that the high ssfr galaxies significantly contribute to the cosmic sfr density of the universe at @xmath7 . .... And you have already written the first three sentences of the full article: recent studies revealed that a significant fraction of stars in the present - day galaxies were formed between redshifts 1 and 3 ( e.g. , * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ?. Please generate the next two sentences of the article
* ; * ? ? ? * ; * ? ? ?
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Suppose that you have an abstract for a scientific paper: following our previous work , we conclude that a grb standard candle constructed from the ghirlanda et al . power - law relation between the geometry - corrected energy ( @xmath0 ) and the peak of the rest - frame prompt burst spectrum ( @xmath1 ) is not yet cosmographically useful , despite holding some potential advantages over sne ia . this is due largely to the small sample of @xmath2 grbs with the required measured redshifts , jet - breaks , and peak energies , and to the strong sensitivity of the goodness - of - fit of the power - law to input assumptions . the most important such finding concerns the sensitivity to the generally unknown density ( and density profile ) , of the circumburst medium . although the @xmath1@xmath0 relation is a highly significant correlation over many cosmologies , until the sample expands to include many low-@xmath3 events , it will be most sensitive to @xmath4 but essentially insensitive to @xmath5 and @xmath6 , with some hope of constraining @xmath7 with high-@xmath3 grb data alone . the relation clearly represents a significant improvement in the search for an empirical grb standard candle , but is further hindered by an unknown physical basis for the relation , the lack of a low-@xmath3 training set to calibrate the relation in a cosmology - independent way , and several major potential systematic uncertainties and selection effects . until these concerns are addressed , a larger sample is acquired , and attempts are made to marginalize or perform monte carlo simulations over the unknown density distribution , we urge caution concerning claims of the utility of grbs for cosmography and especially the attempts to combine grbs with sne ia . [ 1999/12/01 v1.4c il nuovo cimento ] . And you have already written the first three sentences of the full article: it has long been recognized @xcite , that standard candles constructed from long duration gamma - ray bursts ( grbs ) would have several potential advantages over type ia supernovae ( sne ia ) , the most important being high redshift detection . whereas detected sne ia are currently spectrally classifiable out to a maximum of @xmath8 with _ hst _ @xcite ( and in the future with _ snap _ @xcite ) , @xmath9 of grbs with known @xmath3 ( @xmath10 of @xmath11 ) already have measured redshifts @xmath12 .. Please generate the next two sentences of the article
although there are diminishing returns for observations at higher redshifts which primarily probe the matter - dominated regime such measurements may be of great interest if the dark energy shows exotic time variation . in practice , @xmath13 ( @xmath14 of @xmath15 ) grbs in the current sample of bursts with measured redshifts ( @xmath3 ) , jet break times ( @xmath16 ) , and peak energies ( @xmath1 ) , are in the redshift range @xmath17 , which is _ already _ comparable to the number of high - z sne ia discovered with _ hst _ @xcite .
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Suppose that you have an abstract for a scientific paper: in this paper we investigate isospin transport mechanisms in semi - peripheral collisions at fermi energies . the effects of the formation of a low density region ( neck ) between the two reaction partners and of pre - equilibrium emission on the dynamics of isospin equilibration are carefully analyzed . we clearly identify two main contributions to the isospin transport : isospin diffusion due to the @xmath0 ratio and isospin drift due to the density gradients . both effects are sensitive to the symmetry part of the nuclear equation of state ( eos ) , in particular to the value and slope around saturation density . keywords : isospin transport ; binary collisions ; neck dynamics ; symmetry energy . + pacs numbers : 21.30.fe , 25.70.-z , 25.70.lm , 25.70.pq . . And you have already written the first three sentences of the full article: in the last few years the increased accuracy of the experimental techniques has renewed interest in nuclear reactions at fermi energies . exclusive measurements , event - by - event analysis , and a @xmath1 coverage allow a deeper investigation of the evolution of the reaction mechanisms with beam energy and centrality . new insights into the understanding of the nuclear matter equation - of - state ( @xmath2 ) were gained @xcite .. Please generate the next two sentences of the article
in particular , recent experimental and theoretical analyses were devoted to the study of the properties and effects of the symmetry term of the @xmath2 ( asy-@xmath2 ) away from saturation conditions @xcite . indeed , the two - component character of nuclear matter adds some special interest to the dynamics of heavy ion collisions at intermediate energies , between @xmath3 and @xmath4 . in _
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Suppose that you have an abstract for a scientific paper: we experimentally investigate the non - equilibrium steady - state distribution of the work done by an external force on a mesoscopic system with many coupled degrees of freedom : a colloidal crystal mechanically driven across a commensurate periodic light field . since this system mimics the spatiotemporal dynamics of a crystalline surface moving on a corrugated substrate , our results show general properties of the work distribution for atomically flat surfaces undergoing friction . we address the role of several parameters which can influence the shape of the work distribution , e.g. the number of particles used to locally probe the properties of the system and the time interval to measure the work . we find that , when tuning the control parameters to induce particle depinning from the substrate , there is an abrupt change of the shape of the work distribution . while in the completely static and sliding friction regimes the work distribution is gaussian , non - gaussian tails show up due to the spatiotemporal heterogeneity of the particle dynamics during the transition between these two regimes . _ keywords _ : non - equilibrium work fluctuations , stochastic thermodynamics of interacting particles , friction , colloidal crystals . And you have already written the first three sentences of the full article: mt , light potential depth @xmath0 and @xmath1 . the blue bar represents @xmath2 . see text for explanation.,title="fig:",scaledwidth=100.0% ] [ fig : fig0 ] a basic concept for a system driven in a non - equilibrium process by the change of some external parameters is that of work . for mesoscopic systems ,. Please generate the next two sentences of the article
e.g. colloidal particles or biomolecules , the work spent in such a process becomes a fluctuating quantity which follows a probability distribution of finite width @xcite . during the last two decades , various non - equilibrium work relations , above all the jarzynski @xcite and the crooks relations @xcite , have been established and shown to restrict the shape of this probability distribution depending on the underlying specific features of both the system and the non - equilibrium process . from a more fundamental point of view
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Suppose that you have an abstract for a scientific paper: evolutionary algorithms have been used in many ways to generate digital art . we study how evolutionary processes are used for evolutionary art and present a new approach to the transition of images . our main idea is to define evolutionary processes for digital image transition , combining different variants of mutation and evolutionary mechanisms . we introduce box and strip mutation operators which are specifically designed for image transition . our experimental results show that the process of an evolutionary algorithm in combination with these mutation operators can be used as a valuable way to produce unique generative art . . And you have already written the first three sentences of the full article: the field of evolutionary algorithms ( eas ) has been successfully applied to the areas of modern art @xcite . evolutionary computation is an interesting approach to the generation of novel images and is beginning to have a broader impact on artistic fields . more generally , evolutionary methods applied to problem solving in creative fields is an exciting and fast developing topic in computer science . in earlier years research. Please generate the next two sentences of the article
has been conducted using evolutionary algorithms for interactive generation of art . dawkins @xcite and smith @xcite demonstrated the potential of darwinian variation to evolve biomorphs graphic objects . following this steps sims @xcite , latham and todd @xcite
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Suppose that you have an abstract for a scientific paper: we study the creation of a bosonic n00n state from the evolution of a fock state in a double well . while noninteracting bosons disappear quickly in the hilbert space , the evolution under the influence of a bose - hubbard hamiltonian is much more restricted . this restriction is caused by the fragmentation of the spectrum into a high - energy part with doubly degenerate levels and a nondegenerate low - energy part . this degeneracy suppresses transitions to states of the high - energy part of the spectrum . at a moderate interaction strength this effect supports strongly the dynamical formation of a n00n state . the n00n state is suppressed in an asymmetric double well , where the double degeneracy is absent . . And you have already written the first three sentences of the full article: recent experiments on ultracold gases in optical potentials @xcite and experiments on photons in microwave cavities @xcite have demonstrated that it is possible to prepare a fock state as a pure state in a finite - dimensional system . after the preparation of the fock state , the parameters of the system can suddenly be changed ( performing a `` quench '' ) such that the fock state is not an eigenstate of the new system hamiltonian @xmath0 . then the evolution of the many - body state due to the evolution operator @xmath1 will lead to a random walk inside the available hilbert space .. Please generate the next two sentences of the article
the visited states include other fock states as well as superpositions of fock states . typical questions in this context are : what is the probability for visiting different states and how is this affected by the interaction of the particles ?
10,880
Suppose that you have an abstract for a scientific paper: the `` s - f model , '' also known as the ferromagnetic kondo lattice , contains a description of band electrons coupled to localized spins which is an appropriate description of the magnetic part of the low - energy physics of gd metal . here the model is used to estimate the lifetime broadening of the minority spin component of the surface electron band in ferromagnetic gadolinium metal at temperatures below the curie temperature . the low temperature result @xmath00.1 ev agrees nicely with a measurement by fedorov _ et al . _ . And you have already written the first three sentences of the full article: fedorov _ et al . _ @xcite have recently measured the line - shape @xmath1 of photoemitted electrons in the ferromagnetic metal gd . for photoelectrons associated with a photohole in the @xmath2 surface band , they find somewhat different life - time broadening depending on whether the emitted electron has up ( majority ) or down ( minority ) spin .. Please generate the next two sentences of the article
they interpret the source of lifetime broadening to be electron - phonon scattering for the majority spin component of the photohole , and electron - magnon scattering for the minority spin component of the photohole . although the arguments given by fedorov _ et al . _ seem perfectly sensible , nevertheless , this interesting diversity suggests a need for theoretical inquiry .
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Suppose that you have an abstract for a scientific paper: we present a study on the clustering of a stellar mass selected sample of galaxies with stellar masses @xmath0 at redshifts @xmath1 , taken from the palomar observatory wide - field infrared survey . we examine the clustering properties of these stellar mass selected samples as a function of redshift and stellar mass , and find that galaxies with high stellar masses have a progressively higher clustering strength than galaxies with lower stellar masses . we also find that galaxies within a fixed stellar mass range have a higher clustering strength at higher redshifts . we further estimate the average total masses of the dark matter haloes hosting these stellar - mass selected galaxies . for all galaxies in our sample the stellar - mass - to - total - mass ratio is always lower than the universal baryonic mass fraction and the stellar - mass - to - total - mass ratio is strongly correlated with the halo masses for central galaxies , such that more massive haloes contain a lower fraction of their mass in the form of stars . the remaining baryonic mass is included partially in stars within satellite galaxies in these haloes , and as diffuse hot and warm gas . we also find that , at a fixed stellar mass , the stellar - to - total - mass ratio increases at lower redshifts . this suggests that galaxies at a fixed stellar mass form later in lower mass dark matter haloes , and earlier in massive haloes . we interpret this as a ` halo downsizing ' effect . . And you have already written the first three sentences of the full article: stellar masses are now becoming a standard measure for galaxies , and are being used to trace the evolution of the galaxy population in terms of star formation rates and morphologies ( e.g. bundy et al . 2005 ; conselice et al . 2008 ; cowie & barger 2008 ) . however , stellar mass only traces one aspect of galaxy mass , and ideally and ultimately , we aim to measure galaxy total masses , that include contributions from stars , gas , and dark matter .. Please generate the next two sentences of the article
galaxies are believed to be hosted by massive dark matter haloes that make up more than 85% of their total mass , and thus clearly tracing the co - evolution of galaxies and their haloes is a major and important goal . one very powerful method for measuring the total masses of galaxies is to measure their clustering .
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Suppose that you have an abstract for a scientific paper: we propose a perturbative evaluation for the next - to - leading - order ( nlo ) @xmath0 power correction to the photon pion transition form factor @xmath1 . the effects of the nlo power correction are analyzed . # 1/ # 1eq . ( [ # 1 ] ) # 1#2eqs . ( [ # 1]),([#2 ] ) # 1#2 . And you have already written the first three sentences of the full article: the photon - pion transition process @xmath2 provides a good example for tests of qcd . this is because , at tree level in pqcd , there only involve electro - magnetic interactions . the short distance interactions can be calculated in a definite way .. Please generate the next two sentences of the article
the amplitude for the process @xmath2 can be expressed as @xmath3 , where @xmath4 means the pion momentum , @xmath5 and @xmath6 denote the momentum and polarization of the real photon and @xmath7 is the virtuality of the virtual photon . the qcd dynamics are contained in the form factor @xmath8 . in pqcd
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Suppose that you have an abstract for a scientific paper: the present paper reports an inductor - free realization of chua s circuit , which is designed by suitably cascading a single amplifier biquad based active band pass filter with a chua s diode . the system has been mathematically modeled with three - coupled first - order autonomous nonlinear differential equations . it has been shown through numerical simulations of the mathematical model and hardware experiments , that the circuit emulates the behaviors of a classical chua s circuit , e.g. , fixed point behavior , limit cycle oscillation , period doubling cascade , chaotic spiral attractors , chaotic double scrolls and boundary crisis . the occurrence of chaotic oscillation has been established through experimental power spectrum , and quantified with the dynamical measure like lyapunov exponents . = 1 . And you have already written the first three sentences of the full article: design of chaotic electronic circuits offers a great challenge to the research community for the last three decades @xcite-@xcite . the motivation for designing a chaotic electronic circuit comes mainly from two facts : first , one can ` observe ' chaos , and can also control the dynamics of the circuit by simply changing the physically accessible parameters of the circuit , e.g. , resistor , capacitor , voltage levels , etc . ; second , there are multitude of applications of chaotic electronic oscillators starting from chaotic electronic communication to cryptography @xcite-@xcite .. Please generate the next two sentences of the article
a chua s circuit is the first autonomous electronic circuit where a chaotic waveform was observed experimentally , established numerically , and proven theoretically @xcite-@xcite . moreover , it established that chaos is not a mathematical abstraction or numerical artifact , but is a very much realizable phenomenon .
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Suppose that you have an abstract for a scientific paper: in this article , we propose an efficient method for sampling the relevant state space in condensed phase reactions . in the present method , the reaction is described by solving the electronic schrdinger equation for the solute atoms in the presence of explicit solvent molecules . the sampling algorithm uses a molecular mechanics guiding potential in combination with simulated tempering ideas and allows thorough exploration of the solvent state space in the context of an ab initio calculation even when the dielectric relaxation time of the solvent is long . the method is applied to the study of the double proton transfer reaction that takes place between a molecule of acetic acid and a molecule of methanol in tetrahydrofuran . it is demonstrated that calculations of rates of chemical transformations occurring in solvents of medium polarity can be performed with an increase in the cpu time of factors ranging from 4 to 15 with respect to gas - phase calculations . * h * * s * * u * *p * * h * * s * * u * *p * . And you have already written the first three sentences of the full article: the concept of reaction mechanism plays a major role in chemistry and represents a synthesis of our understanding of the way in which different topological changes in the bonding structure of a reactant or product are correlated as the reaction proceeds . recent advances in ultrafast lasers@xcite , x - ray@xcite and other spectroscopies as well as in computational chemistry@xcite have made possible the study of most gas - phase and some condensed - phase reactions in molecular detail . however , most experimental investigations of complex reaction mechanisms taking place in liquid environments are still inferred from isotope and solvent ( medium ) effects on the reaction rate@xcite . consequently , the interpretation of the experimental results as well as the reaction mechanisms inferred are more controversial than those of gas - phase reactions .. Please generate the next two sentences of the article
computer studies can be useful as a complement to experimental data in cases where experiments alone can not provide a definitive picture of the mechanism of the chemical process . it is therefore desirable to develop systematic computational approaches to carefully examine the relation between isotope effects and reaction mechanism in condensed phase systems .
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Suppose that you have an abstract for a scientific paper: a classical system can not escape out of a metastable state at zero temperature . however , a composite system made from both classical and quantum degrees of freedom may drag itself out of the metastable state by a sequential process . the sequence starts with the tunneling of the quantum component which then triggers a distortion of the trapping potential holding the classical part . provided this distortion is large enough to turn the metastable state into an unstable one , the classical component can escape . this process reminds of the famous baron mnchhausen who told the story of rescuing himself from sinking in a swamp by pulling himself up by his own hair we thus term this decay the ` mnchhausen effect ' . we show that such a composite system can be conveniently studied and implemented in a dc - squid featuring asymmetric dynamical parameters . we determine the dynamical phase diagram of this system for various choices of junction parameters and system preparations . . And you have already written the first three sentences of the full article: consider a classical object ( a degree of freedom ) trapped in a metastable potential minimum ; no decay out of this metastable state is possible at low temperatures , where thermal activation over the barrier is exponentially suppressed . however , if the classical object is a composite one , with a quantum degree of freedom coupled to the classical one , then the quantum object may tunnel out of the metastable minimum and exert a pulling force on the classical object . once the latter is large enough to completely suppress the trapping barrier , the classical object is able to leave the potential well hence a classical object may escape from a metastable state even at zero temperature if helped by a coupled quantum degree of freedom .. Please generate the next two sentences of the article
the above situation can be realized in a dc - squid ( superconducting quantum interference device ) featuring asymmetric dynamical parameters ; i.e. , with two josephson junctions of equal critical currents @xmath0 but strongly different ( shunt ) capacitances @xmath1 and ( shunt ) resistances @xmath2 , see fig . [ fig : setup ] ; choosing large and small parameters @xmath1 and @xmath3 for the two junctions allows to place one of the junctions in the ` classical ' and the other into the quantum domain .
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Suppose that you have an abstract for a scientific paper: we give a sufficient condition under which vanishing property of cochran orr teichner knot concordance obstructions splits under connected sum . the condition is described in terms of self - annihilating submodules with respect to higher - order blanchfield linking forms . this extends results of levine and the authors on distinguishing knots with coprime alexander polynomials up to concordance . as an application , we show that the knots constructed by cochran , orr and teichner as the first examples of nonslice knots with vanishing casson gordon invariants are not concordant to any knot of genus 1 . . And you have already written the first three sentences of the full article: knots @xmath0 and @xmath1 in the 3sphere @xmath2 are said to be _ concordant _ if there exists a ( topologically ) locally flat properly embedded annulus @xmath3 $ ] in @xmath4 $ ] whose boundary is the union of @xmath5 and @xmath6 . here @xmath7 denotes the mirror image of @xmath1 with reversed string orientation . a knot which is concordant to the unknot is said to be _. Please generate the next two sentences of the article
equivalently , a knot is slice if and only if it bounds a locally flat 2disk in the 4ball . it is well - known that @xmath0 is concordant to @xmath1 if and only if the connected sum @xmath8 is slice . concordance classes , which are the equivalence classes of knots modulo concordance , form an abelian group under connected sum , and this abelian group is called _ the knot concordance group @xmath9_. in the group @xmath9 , the identity is the class of slice knots , and the inverse of the concordance class of @xmath0 is that of @xmath10 . in the 1960 s , levine @xcite defined _ the algebraic knot concordance group @xmath11 _ using seifert forms of knots , and showed that there is a surjective homomorphism @xmath12 .
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Suppose that you have an abstract for a scientific paper: i describe the conceptual and mathematical basis of an approach which describes gravity as an emergent phenomenon . combining the principle of equivalence and the principle of general covariance with known properties of local rindler horizons , perceived by observers accelerated with respect to local inertial frames , one can provide a thermodynamic re - interpretation of the field equations describing gravity in any diffeomorphism invariant theory . this fact , in turn , leads us to the possibility of deriving the field equations of gravity by maximising a suitably defined entropy functional , without using the metric tensor as a dynamical variable . the approach synthesizes concepts from quantum theory , thermodynamics and gravity leading to a fresh perspective on the nature of gravity . the description is presented here in the form of a dialogue , thereby addressing several frequently - asked - questions . . And you have already written the first three sentences of the full article: 0.2cm**harold : * * for quite sometime now , you have been talking about ` gravity being an emergent phenomenon ' and a ` thermodynamic perspective on gravity ' . this is quite different from the conventional point of view in which gravity is a fundamental interaction and spacetime thermodynamics of , say , black holes is a particular result which can be derived in a specific context . honestly , while i find your papers fascinating i am not clear about the broad picture you are trying to convey . maybe you could begin by clarifying what this is all about , before we plunge into the details ? what is the roadmap , so to speak ?. Please generate the next two sentences of the article
0.2cm**me : * * to begin with , i will show you that the equations motion describing gravity in _ any diffeomorphism invariant theory _ can be given @xcite a suggestive thermodynamic re - interpretation ( sections [ sec : lro ] , [ sec : reinterpret ] ) . second , taking a cue from this , i can formulate a variational principle for a suitably defined entropy functional involving both gravity and matter which will lead to the field equations of gravity @xcite without varying the metric tensor as a dynamical variable ( section [ sec : eqnnewvar ] ) .
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Suppose that you have an abstract for a scientific paper: the fluka monte carlo program is used to predict the distributions of the muons which originate from primary cosmic gamma rays and reach sea level . the main result is the angular distribution of muons produced by vertical gamma rays which is necessary to predict the inherent angular resolution of any instrument utilizing muons to infer properties of gamma ray primaries . furthermore , various physical effects are discussed which affect these distributions in differing proportions . air shower simulation , gamma rays , muons 95.75.pq , 98.70.sa , 98.70.rz , 13.60.le . And you have already written the first three sentences of the full article: muons detected at ground level arise mainly as decay products of charged mesons . these mesons are created abundantly in hadronic showers , most of which are caused by primary cosmic ray protons and nuclei interacting inelastically with the nuclei of the atmosphere . a small fraction of muons , however , have their first origin in photonuclear reactions induced by primary or secondary cosmic gamma rays . several authors have performed analytical or monte carlo calculations of the muon flux produced in gamma showers ( see references [ 10 - 21 ] of @xcite ) .. Please generate the next two sentences of the article
most of these calculations were one dimensional and all of them referred to gamma energies much larger than 10 tev . despite their relative scarcity compared to the large background of muons from hadron - generated showers , muons originating from primary gamma ray interactions are important for ground - based high statistics cosmic ray experiments which are sensitive to energies @xmath0 tev such as milagro @xcite and grand @xcite . cosmic gamma rays , unlike charged hadrons , are unaffected by the earth s and galactic magnetic fields and their direction points directly to the location of their source .
10,889
Suppose that you have an abstract for a scientific paper: we discuss the afterglow emission from a relativistic jet that is initially in the radiative regime in which the accelerated electrons are fast cooling . we note that such a `` semiradiative '' jet decelerates faster than an adiabatic jet does . we also take into account the effect of strong inverse - compton scattering on the cooling frequency in the synchrotron component and therefore on the light curve decay index . we find that there are two kinds of light - curve break for the jet effect . the first is an `` adiabatic break '' if the electrons become slow cooling before the jet enters a spreading phase , and the second is a `` radiative break '' which appears on the contrary case . we then show how a relativistic jet evolves dynamically and derive the overall temporal synchrotron emission in both cases , focusing on the change in light curve decay index around the break time . finally , in view of our results , we rule out two cases for relativistic jets to account for the observed light curve breaks in a few afterglows : ( i ) an adiabatic jet with strong compton cooling ( @xmath0 ) and with the cooling frequency @xmath1 locating in the observed energy range ; ( ii ) a radiative jet with a significant fraction of total energy occupied by electrons ( @xmath2 ) . -0.5 cm gamma rays : bursts radiation mechanisms : non - thermal . And you have already written the first three sentences of the full article: it is widely believed that gamma - ray bursts ( grbs ) and their afterglows are caused by the dissipation of kinetic energy of an ultrarelativistic ejecta , with lorentz factor @xmath3 , releasing from the central engine ( so - called fireball " model , see piran 1999 and van paradijs , kouveliotou & wijers 2000 for detailed reviews ) . grbs are the most energetic explosive phenomena in astronomy . in the fireball model , the collisions among different shells within the ejecta might be expected to produce a prompt burst ( paczyski & xu 1994 ; rees & mszros 1994 ) , and subsequently the ejecta interacts with its surrounding medium , producing a long - term and broad - band afterglow ( paczyski & rhoads 1993 ; mszros & rees 1997 ) . in the standard afterglow picture , the ejecta drives a relativistic blast wave expanding into the surrounding medium , which approaches a self - similar solution ( blandford & mckee 1976 ) after a short time once the swept - up medium attains an energy comparable to the initial energy of the burst .. Please generate the next two sentences of the article
electrons in the cold medium are heated in the shock front to highly relativistic energy and produce a broad - band afterglow via synchrotron / inverse - compton emission . the predicted emission spectrum and light curve ( mszros & rees 1997 ; sari et al . 1998 ) have met essential successes in describing the behavior of afterglows ( e.g. , vietri 1997 ; waxman 1997ab ; wijers et al .
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Suppose that you have an abstract for a scientific paper: we focus on the ground state phase diagram of a system of spinless fermions with repulsion on a hypercubic lattice in the limit of infinite dimensions . it occurs spontaneous symmetry breaking into a charge density wave ( cdw ) . using an ansatz for the order parameter which includes the homogeneous , the ab- and a large class of incommensurate phases we are able to calculate the phase diagram . + july 20 , 1994 univ . zu kln + uva / itf 16/94 * existence of an incommensurate ground state of interacting spinless fermions in infinite dimensions * + g.s . uhrig@xmath0 and r. vlaming@xmath1 + @xmath0 _ inst . f. theor . physik , univ . zu kln , 50937 kln , germany _ + @xmath1 _ inst . v. theor . fysica , uva , 1018 xe , amsterdam , the netherlands _ + it is an important object to disclose the structure of the phase diagram of models with strong electron correlation . the problem is twofold . first , one has to have a clear picture which phases are likely to be realised and second , for these phases it must be possible to calculate the free energy . in case of the hubbard model for example both problems can hardly be surmounted . even if one restricts oneself to a small number of phases and to the dynamic mean field theory resulting from the limit of high dimensions @xcite , the problem still requires massive computational effort ( e.g. @xcite ) . the situation is different for the model of interacting spinless fermions @xcite on an infinite dimensional hypercubic lattice . although the diagrammatic theory is simple , the physics is far from trivial . the hamiltonian of the spinless fermion model in second quantisation is @xmath2 scaling with the inverse dimension @xmath3 is performed to ensure the continuity of the limit of infinite dimensions @xcite . in a previous work the stability of the homogeneous phase was investigated in the limit @xmath4 @xcite . in this limit hartree- and random phase approximation become exact @xcite . besides the occurrence.... And you have already written the first three sentences of the full article: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ * figure 1 . * ground state energy for @xmath53 . dotted curve : homogeneous phase .. Please generate the next two sentences of the article
dotted - dashed curve : ab phase . solid curve : incommensurate phase ( @xmath8 optimised ) .
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Suppose that you have an abstract for a scientific paper: here we introduce a new model of natural textures based on the feature spaces of convolutional neural networks optimised for object recognition . samples from the model are of high perceptual quality demonstrating the generative power of neural networks trained in a purely discriminative fashion . within the model , textures are represented by the correlations between feature maps in several layers of the network . we show that across layers the texture representations increasingly capture the statistical properties of natural images while making object information more and more explicit . the model provides a new tool to generate stimuli for neuroscience and might offer insights into the deep representations learned by convolutional neural networks . . And you have already written the first three sentences of the full article: the goal of visual texture synthesis is to infer a generating process from an example texture , which then allows to produce arbitrarily many new samples of that texture . the evaluation criterion for the quality of the synthesised texture is usually human inspection and textures are successfully synthesised if a human observer can not tell the original texture from a synthesised one . in general , there are two main approaches to find a texture generating process . the first approach is to generate a new texture by resampling either pixels @xcite or whole patches @xcite of the original texture .. Please generate the next two sentences of the article
these non - parametric resampling techniques and their numerous extensions and improvements ( see @xcite for review ) are capable of producing high quality natural textures very efficiently . however , they do not define an actual model for natural textures but rather give a mechanistic procedure for how one can randomise a source texture without changing its perceptual properties .
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Suppose that you have an abstract for a scientific paper: in this paper we propose a new lifetime model , called the odd generalized exponential gompertz distribution , we obtained some of its mathematical properties . some structural properties of the new distribution are studied . the method of maximum likelihood is used for estimating the model parameters and the observed fisher s information matrix is derived . we illustrate the usefulness of the proposed model by applications to real data . ' '' '' * keywords : * _ gompertz distribution ; hazard function ; moments ; maximum likelihood estimation . _ * 2010 msc : * _ 60e05 , 62f10 , 62f12 , 62n02 , 62n05 . _ . And you have already written the first three sentences of the full article: in the analysis of lifetime data we can use the gompertz , exponential and generalized exponential distributions . it is known that the exponential distribution have only constant hazard rate function where as gompertz , and generalized exponential distributions can have only monotone ( increasing in case of gompertz and increasing or decreasing in case of generalized exponential distribution ) hazard rate . these distributions are used for modelling the lifetimes of components of physical systems and the organisms of biological populations .. Please generate the next two sentences of the article
the gompertz distribution has received considerable attention from demographers and actuaries . pollard and valkovics @xcite were the first to study the gompertz distribution , they both defined the moment generating function of the gompertz distribution in terms of the incomplete or complete gamma function and their results are either approximate or left in an integral form . later , marshall and olkin @xcite described the negative gompertz distribution ; a gompertz distribution with a negative rate of aging parameter .
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Suppose that you have an abstract for a scientific paper: a new two - dimensional ( 2d ) material , borophene ( 2d boron sheet ) , has been grown successfully recently on single crystal ag substrates by two parallel experiments [ mannix _ et al . , science _ , 2015 , * 350 * , 1513 ] [ feng _ et al . , nature chemistry _ , 2016 , * advance online publication * ] . three main structures have been proposed ( @xmath0 , @xmath1 and striped borophene ) . however , the stability of three structures is still in debate . using first principles calculations , we examine the dynamical , thermodynamical and mechanical stability of @xmath0 , @xmath1 and striped borophene . free - standing @xmath0 and @xmath1 borophene is dynamically , thermodynamically , and mechanically stable , while striped borophene is dynamically and thermodynamically unstable due to high stiffness along @xmath2 direction . the origin of high stiffness and high instability in striped borophene along @xmath2 direction can both be attributed to strong directional bonding . this work provides a benchmark for examining the relative stability of different structures of borophene . . And you have already written the first three sentences of the full article: recent years have witnessed many breakthroughs in research on two - dimensional ( 2d ) materials due to their potential applications in next - generation electronic and energy conversion devices @xcite . recently , a new type of 2d material , borophene ( 2d boron sheet ) @xcite , has been successfully grown on single crystal ag(111 ) substrates by two parallel experiments @xcite . although various proposals of stable 2d boron sheets and quasiplanar boron clusters have been made @xcite , three main structures ( @xmath0 , @xmath1 and striped borophene ) have been observed by scanning tunneling microscopy in these two experiments : @xmath0 and @xmath1 borophene has planar structure with periodic holes @xcite , while striped borophene has buckled structure with anisotropic corrugation @xcite .. Please generate the next two sentences of the article
the following first principles calculations have predicted that striped borophene possesses remarkable mechanical properties @xcite , which may rival graphene @xcite . however , phonon instability in striped borophene is observed @xcite , which may challenge previous results demonstrating that borophene is stiffer than graphene along @xmath2 direction @xcite . theoretical investigation of the formation of boron sheet on ag(111 ) surface has demonstrated that stable boron sheet should contain 1/6 vacancies in a striped pattern @xcite .
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Suppose that you have an abstract for a scientific paper: intensity of the first- and the second - order raman spectra are calculated as a function of the fermi energy . we show that the kohn anomaly effect , i.e. , phonon frequency renormalization , in the first - order raman spectra originates from the phonon renormalization by the interband electron - hole excitation , whereas in the second - order raman spectra , a competition between the interband and intraband electron - hole excitations takes place . by this calculation , we confirm the presence of different dispersive behaviors of the raman peak frequency as a function of the fermi energy for the first- and the second - order raman spectra , as observed in experiments . moreover , the calculated results of the raman intensity sensitively depend on the fermi energy for both the first- and the second - order raman spectra . these results thus also show the importance of quantum interference effect phenomena . . And you have already written the first three sentences of the full article: applying an electric gate voltage to graphene provides exotic tuning of the electronic , vibrational , and optical properties of graphene samples @xcite . since the beginning of graphene s discovery , electronic gating has played an important role in elucidating the room temperature quantum hall effect @xcite , the klein tunneling @xcite , and many body coupling effects @xcite . similar gating techniques are extensively applied not only to monolayer , but also to multilayer graphene to obtain tunable transport @xcite , a tunable band gap @xcite , p - n junctions @xcite , and photodetectors @xcite .. Please generate the next two sentences of the article
all of these exciting phenomena could be observed due to the ability of tuning graphene s fermi energy @xmath0 through the applied gate voltage . a combination of electronic gating and inelastic scattering of light , known as the gate modulated raman spectroscopy @xcite , opens up a new possibility to understand more thouroughly the interplay of the electron , photon and phonon exitations in graphene .
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Suppose that you have an abstract for a scientific paper: an exchange energy functional is proposed and tested for obtaining a class of excited - state energies using density - functional formalism . the functional is the excited - state counterpart of the local - density approximation functional for the ground - state . it takes care of the state - dependence of the energy functional and leads to highly accurate excitation energies . . And you have already written the first three sentences of the full article: success of density functional theory ( dft ) @xcite for the ground - state calculations had prompted search @xcite for similar theories for the excited - states . over the past decade , time - dependent density - functional theory ( tddft ) @xcite has become a standard tool @xcite for obtaining transition energies and the associated oscillator strengths . however , despite its widespread use , the theory is not without limitations . for example , calculating excitation energies for double excitation of electrons still remains @xcite a challenge in the tddft approach . at the same time , the charm of getting the excitation energy as the difference between two total energies remains .. Please generate the next two sentences of the article
this is because one can choose the excited - state at will , promoting as many electrons as one wishes to a set of chosen orbitals , calculate the total corresponding energy and find the excitation energy by subtracting the ground - state energy . thus research in the direction of performing a kohn - sham like calculation for the excited - states continues . a ground - state like dft approach to obtain the total energy of an excited - state has been developed by grling @xcite and by levy and nagy @xcite .
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Suppose that you have an abstract for a scientific paper: let @xmath0 be a simple graph of order @xmath1 . the domination polynomial of @xmath0 is the polynomial @xmath2 , where @xmath3 is the number of dominating sets of @xmath0 of size @xmath4 . the @xmath1-barbell graph @xmath5 with @xmath6 vertices , is formed by joining two copies of a complete graph @xmath7 by a single edge . we prove that for every @xmath8 , @xmath5 is not @xmath9-unique , that is , there is another non - isomorphic graph with the same domination polynomial . more precisely , we show that for every @xmath1 , the @xmath9-equivalence class of barbell graph , @xmath10 $ ] , contains many graphs , which one of them is the complement of book graph of order @xmath11 , @xmath12 . also we present many families of graphs in @xmath9-equivalence class of @xmath13 . department of mathematics , yazd university , 89195 - 741 , yazd , iran + [email protected] * keywords : * domination polynomial ; @xmath9-unique ; equivalence ; generalize barbell graphs . * ams subj . class . : * 05c60 , 05c69 . And you have already written the first three sentences of the full article: all graphs in this paper are simple of finite orders , i.e. , graphs are undirected with no loops or parallel edges and with finite number of vertices . the _ complement _ @xmath14 of a graph @xmath0 , is a graph with the same vertex set as @xmath0 and with the property that two vertices are adjacent in @xmath14 if and only if they are not adjacent in @xmath0 . for any vertex @xmath15 ,. Please generate the next two sentences of the article
the _ open neighborhood _ of @xmath16 is the set @xmath17 and the _ closed neighborhood _ of @xmath16 is the set @xmath18=n(v)\cup \{v\}$ ] . for a set @xmath19 , the open neighborhood of @xmath20 is @xmath21 and the closed neighborhood of @xmath20 is @xmath22=n(s)\cup s$ ] .
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Suppose that you have an abstract for a scientific paper: we propose a new method to immunize populations or computer networks against epidemics which is more efficient than any method considered before . the novelty of our method resides in the way of determining the immunization targets . first we identify those individuals or computers that contribute the least to the disease spreading measured through their contribution to the size of the largest connected cluster in the social or a computer network . the immunization process follows the list of identified individuals or computers in inverse order , immunizing first those which are most relevant for the epidemic spreading . we have applied our immunization strategy to several model networks and two real networks , the internet and the collaboration network of high energy physicists . we find that our new immunization strategy is in the case of model networks up to @xmath0 , and for real networks up to @xmath1 more efficient than immunizing dynamically the most connected nodes in a network . our strategy is also numerically efficient and can therefore be applied to large systems . . And you have already written the first three sentences of the full article: the threat of global spreading of epidemics , like the pandemic flu from 2009 , or spreading of computer viruses which are endangering the functioning of internet dependent facilities , are responsible for the enormous increase in public interest on immunization during the last years . much progress has been achieved in understanding epidemic spreading @xcite , and various models have been developed suggesting possible ways of efficient immunization @xcite . however , the search for even more effective immunization strategies must be pursued since any improvement of immunization efficiency can save human lives and resources . in this paper. Please generate the next two sentences of the article
we introduce a novel immunization strategy based on inverse targeting , which proves to be effective and numerically more efficient than any proposed previous one . epidemics can spread in human population through networks of social contacts , and viruses can propagate on computer networks .
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Suppose that you have an abstract for a scientific paper: quasi - periodic brightness oscillations ( qpos ) with frequencies ranging from @xmath0300 hz to @xmath01200 hz have been discovered in the x - ray emission from fourteen neutron stars in low - mass binary systems and from another neutron star in the direction of the galactic center . these kilohertz qpos are very strong , with rms relative amplitudes ranging up to @xmath015% of the total x - ray countrate , and are remarkably coherent , with frequency to fwhm ratios as large as @xmath0200 . two simultaneous kilohertz qpos differing in frequency by @xmath0250350 hz have been detected in twelve of the fifteen sources . here we propose a model for these qpos . in this model the x - ray source is a neutron star with a surface magnetic field @xmath1 g and a spin frequency of a few hundred hertz , accreting gas via a keplerian disk . some of the accreting gas is channeled by the stellar magnetic field but some remains in a keplerian disk flow that penetrates to within a few kilometers of the stellar surface . the frequency of the higher - frequency qpo in a kilohertz qpo pair is the keplerian frequency at a radius near the sonic point at the inner edge of the keplerian flow whereas the frequency of the lower - frequency qpo is approximately the difference between the keplerian frequency at a radius near the sonic point and the stellar spin frequency . the difference between the frequencies of the pair of qpos is therefore close to ( but not necessarily exactly equal to ) the stellar spin frequency . the amplitudes of the qpos at the sonic - point keplerian frequency and at the beat frequency depend on the strength of the neutron star s magnetic field and the accretion rate and hence one or both of these qpos may sometimes be undetectable . oscillations at the stellar spin frequency and its overtones are expected to be weak but may sometimes be detectable . this model is consistent with the magnetic field strengths , accretion rates , and scattering optical depths inferred from.... And you have already written the first three sentences of the full article: observations of accreting neutron stars in low - mass x - ray binaries ( lmxbs ) with the _ rossi x - ray timing explorer _ have revealed that the persistent x - ray emission of at least fifteen show remarkably coherent quasi - periodic brightness oscillations ( qpos ) , with frequencies @xmath5 ranging from @xmath0300 hz to @xmath01200 hz . these kilohertz qpos are the highest - frequency oscillations ever seen in any astrophysical object . eight of the fourteen identified sources in which kilohertz qpos have been detected are `` atoll '' sources ( , , , , , , , and ) .. Please generate the next two sentences of the article
kilohertz qpos have also been detected in all six of the originally identified `` z '' sources ( 1 , , , , , and ) . ( for the definitions of atoll and z sources , see hasinger & van der klis 1989 . ) highly coherent brightness oscillations with frequencies ranging from @xmath0360 hz to @xmath0580 hz have been detected during type i ( thermonuclear ) x - ray bursts from four kilohertz qpo sources .
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Suppose that you have an abstract for a scientific paper: we use the sample of known stars and brown dwarfs within 5 pc of the sun , supplemented with afgk stars within 10 pc , to determine which stellar spectral types provide the most habitable real estate defined to be locations where liquid water could be present on earth - like planets . stellar temperatures and radii are determined by fitting model spectra to spatially resolved broad - band photometric energy distributions for stars in the sample . using these values , the locations of the habitable zones are calculated using an empirical formula for planetary surface temperature and assuming the condition of liquid water , called here the empirical habitable zone , or ehz . systems that have dynamically disruptive companions , assuming a 5:1 separation ratios for primary / secondary pairs and either object and a planet , are considered not habitable . we use the results of these calculations to derive a simple formula to predict the location of the ehz for main sequence stars based on @xmath0 color . we consider ehz widths as more useful measures of the habitable real estate around stars than areas because multiple planets are not expected to orbit stars at identical stellar distances . this ehz provides a qualitative guide on where to expect the largest population of planets in the habitable zone of main sequence stars . because of their large numbers and lower frequency of short - period companions , m stars provide more ehz real estate than other spectral types , possessing 36.5% of the habitable real estate _ en masse_. k stars are second with 21.5% , while a , f , and g stars offer 18.5% , 6.9% and 16.6% , respectively . our calculations show that three m dwarfs within 10 pc harbor planets in their ehzs gj 581 may have two planets ( d with @xmath1sin@xmath2 = 6.1 @xmath3 ; g with @xmath1sin@xmath2 = 3.1 @xmath3 ) , gj 667 c has one ( c with @xmath1sin@xmath2 = 4.5 @xmath3 ) , and gj 876 has two ( b with @xmath1sin@xmath2 = 1.89 @xmath4 and c with @xmath1sin@xmath2 = 0.56 @xmath4 ) . if.... And you have already written the first three sentences of the full article: early astronomers looked to the sky and saw the moon as a habitable world covered in vast oceans , venus as a swampy marshland enshrouded in clouds , and mars with grand canals ( lowell 1895 ) . not one of these worlds has maintained its promise of abundant life . instead , the solar system , once thought to be teeming with life , may be barren , although hope remains for environments under the icy crust of europa ( marion et al .. Please generate the next two sentences of the article
2003 ) , in the tiger stripes of enceladus ( parkinson et al . 2007 ) , in water under the martian surface ( malin & edgett 2000 ) , or perhaps lurking somewhere as yet unidentified . with the discovery of more than 700 extrasolar planets since 1989 , the real estate market in our solar system is no longer the only place we might look for evidence of life beyond earth .