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3,100 | Suppose that you have an abstract for a scientific paper: we obtained new ubv photometry and spectroscopy of blue plume ( bp ) stars near the center of the canis major over - density ( cma ) .
we combined analyses of color - color diagrams with a new comparison of the hydrogen balmer - line profile to the reddening - free q parameter to improve the reddening and extinction estimates for this low - latitude , differentially reddened , area of the sky .
results of our stellar parameter analysis for b / a spectral type stars associated with the bp show that the majority of the stars have main - sequence surface gravities placing them at an average heliocentric distance of @xmath0d@xmath1 = @xmath2 kpc .
this distance is more consistent with membership in the intervening perseus spiral arm and strongly suggests that the bp stars are not associated with the other stellar populations previously reported to make up the cma .
this result casts serious doubt on the proposed dwarf galaxy origin for the cma . .
And you have already written the first three sentences of the full article: the nature of the cma , discovered by @xcite , remains a controversial subject .
whether the cma is a distinct , disrupting dwarf galaxy or a feature of the galactic disk remains open to debate .
previous studies using either 2mass or broadband johnson - cousins photometry have shown indications that over - densities in the red giant branch ( rgb ) , red clump ( rc ) and old main - sequence ( oms)(age = 4 - 10 gyrs ) exist , centered near l = 240 , b = -7 . each of these populations lie red - ward of the thin / thick disk turnoff and are identified using statistical methods which compare expected model densities to observations ..
Please generate the next two sentences of the article | this type of analysis is necessitated because of the enormous number of foreground / background stars along the line - of - sight for these samples .
results from these investigations are confounded by the difficulty in constraining the differential reddening which is prevalent in this portion of the sky . |
3,101 | Suppose that you have an abstract for a scientific paper: we consider and compare the structural properties of bulk tip4p water and of a sodium chloride aqueous solution in tip4p water with concentration c = 0.67 mol / kg , in the metastable supercooled region . in a previous paper [ d. corradini , m. rovere and p. gallo , j. chem .
phys . * 132 * , 134508 ( 2010 ) ] we found in both systems the presence of a liquid - liquid critical point ( llcp ) .
the llcp is believed to be the end point of the coexistence line between a high density liquid ( hdl ) and a low density liquid ( ldl ) phase of water . in the present paper
we study the different features of water - water structure in hdl and ldl both in bulk water and in the solution .
we find that the ions are able to modify the bulk ldl structure , rendering water - water structure more similar to the bulk hdl case . by the study of the hydration structure in hdl and ldl , a possible mechanism for the modification of the bulk ldl structure in the solution
is identified in the substitution of the oxygen by the chloride ion in oxygen coordination shells . .
And you have already written the first three sentences of the full article: the possible existence of a second critical point of water in the liquid supercooled metastable phase has been the subject of a long debate in the literature .
the first hypothesis of its existence originated from the results of a computer simulation on water modeled with the st2 potential @xcite .
on the basis of those results the thermodynamic anomalies of water upon supercooling were interpreted in terms of the long range fluctuations induced by the presence of a second critical point ..
Please generate the next two sentences of the article | this critical point would be a liquid - liquid critical point ( llcp ) located at the end of the coexistence line between a low density liquid ( ldl ) phase and a high density liquid ( hdl ) phase of water . in the llcp scenario
, these liquid phases would be the counterpart at higher temperature of the well - known low density amorphous ( lda ) and high density amorphous ( hda ) phases of glassy water . |
3,102 | Suppose that you have an abstract for a scientific paper: in this presentation i will primarily focus on top quark physics but i will include a discussion of the w - boson mass and the possibility of discovering a light higgs boson via associated production at the tevatron .
= cmr8 epsf 1.5pt # 1#2#3#4#1 * # 2 * , # 3 ( # 4 ) # 1(#3)=@urnal , _ # 1 * # 2 ( @ur 255=#3 ) , * _ @ur255<100 255 by 1900 255 @urnal @=reference foul up : nested macros = you forgot & or ( ) after the last # 1,#3(#4 ) , # 1 * # 2 * , # 3 ( 19#4 ) ps . ps .
And you have already written the first three sentences of the full article: the top quark is the heaviest `` elementary '' particle with a mass approximately equal to the sum of the masses of the w - boson and z - boson .
the top quark , the w - boson and the higg boson form an interesting triptych of elementary particles . in the standard model knowing the mass of the w - boson and top quark allows one to predict the mass of the higgs boson . therefore in this proceedings
i will primarily focus on the top quark physics but i will also discuss the w - boson mass and the possibility of discovering the light higgs boson at the proton - antiproton collider at fermilab , the tevatron ..
Please generate the next two sentences of the article | the most surprising thing about the top quark is that its mass is approximately 175 gev , nearly twice as heavy as the w and z bosons and more than 30 times the mass of its electro - weak partner the b - quark .
the yukawa coupling constant of the top quark m_t & ~ & 1 whereas for the electron the yukawa coupling is @xmath0 . |
3,103 | Suppose that you have an abstract for a scientific paper: a resonance - like structure , the @xmath0 , has recently been observed in the @xmath1 spectrum by the lhcb collaboration .
we discuss the feasibility of detecting this structure in @xmath2 photoproduction in the clas12 experiment at jlab .
we present a first estimate of the upper limit for the branching ratio of the @xmath0 to @xmath1 .
our estimates , which take into account the experimental resolution effects , predict that it will be possible to observe a sizable cross section close to the @xmath3 production threshold and shed light on the @xmath0 resonance in the future photoproduction measurements . .
And you have already written the first three sentences of the full article: exotic hadron spectroscopy opens a new window into quark - gluon dynamics that could shift the paradigm that mesons and baryons consist of @xmath4 and @xmath5 constituent quarks , respectively .
recent lattice qcd studies of the nucleon spectrum indicate that the excited nucleon states may exist with a substantial admixture of glue @xcite .
these recent predictions initiated the efforts aimed at a search for hybrid baryons in the future experiments at jefferson lab with the clas12 detector @xcite . in this paper.
Please generate the next two sentences of the article | we discuss the feasibility of using the clas12 detector in search for exotic baryons with the quark core consisting of five constituent quarks including charm .
this is motivated by refs . |
3,104 | Suppose that you have an abstract for a scientific paper: in late 2008 , the quasi - persistent neutron star x - ray transient and eclipsing binary exo 0748676 started a transition from outburst to quiescence , after it had been actively accreting for more than 24 years . in a previous work
, we discussed _
chandra _ and
_ swift _ observations obtained during the first five months after this transition . here
, we report on further x - ray observations of exo 0748676 , extending the quiescent monitoring to 1.6 years .
_ chandra _ and _ xmm - newton _ data reveal quiescent x - ray spectra composed of a soft , thermal component that is well - fitted by a neutron star atmosphere model . an additional hard powerlaw tail is detected that changes non - monotonically over time , contributing between 4 and 20 percent to the total unabsorbed 0.510 kev flux .
the combined set of _ chandra _ , _ xmm - newton _ and _ swift _
data reveals that the thermal bolometric luminosity fades from @xmath0 to @xmath1 , whereas the inferred neutron star effective temperature decreases from @xmath2 to @xmath3 ev .
we interpret the observed decay as cooling of the neutron star crust and show that the fractional quiescent temperature change of exo 0748676 is markedly smaller than observed for three other neutron star x - ray binaries that underwent prolonged accretion outbursts .
[ firstpage ] accretion , accretion disks - binaries : eclipsing - stars : individual ( exo 0748676 ) - stars : neutron - x - rays : binaries .
And you have already written the first three sentences of the full article: exo 0748676 is an intensively studied low - mass x - ray binary that was initially discovered with the european x - ray observatory satellite ( _ exosat _ ) in 1985 february @xcite .
however , in retrospect the source already appeared active in _ exosat _
slew survey observations several times beginning 1984 july @xcite , whereas the earliest detection dates back to 1980 may , when exo 0748676 was serendipitously observed with the _ einstein _ satellite @xcite ..
Please generate the next two sentences of the article | the system exhibits irregular x - ray dips and displays eclipses that last for @xmath4 min and recur every 3.82 hr , which allow the unambiguous determination of the orbital period of the binary @xcite .
the detection of type - i x - ray bursts ( e.g. , * ? ? ? |
3,105 | Suppose that you have an abstract for a scientific paper: we report the discovery of a high mass - ratio planet @xmath0 , i.e. , 13 times higher than the jupiter / sun ratio .
the host mass is not presently measured but can be determined or strongly constrained from adaptive optics imaging .
the planet was discovered in a small archival study of high - magnification events in pure - survey microlensing data , which was unbiased by the presence of anomalies .
the fact that it was previously unnoticed may indicate that more such planets lie in archival data and could be discovered by similar systematic study . in order to understand the transition from predominantly survey+followup to predominately survey - only planet detections , we conduct the first analysis of these detections in the observational @xmath1 plane . here
@xmath2 is projected separation in units of the einstein radius .
we find some evidence that survey+followup is relatively more sensitive to planets near the einstein ring , but that there is no statistical difference in sensitivity by mass ratio . .
And you have already written the first three sentences of the full article: for the first decade of microlens planet detections , beginning with ogle-2003-blg-235 lb @xcite , the great majority of detections required a combination of survey and followup data .
this is a consequence of two effects .
first , the survey coverage was generally too sparse to characterize the planetary anomalies in the detected events @xcite ..
Please generate the next two sentences of the article | second , thanks to aggressive alert capability , pioneered by the optical gravitational lensing experiment ( ogle ) early warning system ( ews , @xcite ) , it became possible to organize intensive followup of planet - sensitive events or even ongoing planetary anomalies and so obtain sufficient time resolution to detect and characterize the planets .
however , as surveys have become more powerful over the past decade , they have become increasingly capable of detecting planets without follow up observations . |
3,106 | Suppose that you have an abstract for a scientific paper: the ellipticity function of cosmic voids exhibits strong dependence on the amplitude of the linear matter power spectrum . analyzing the most recent void catalogs constructed by foster and nelson from the fifth data release of the sloan digital sky survey , we measure observationally the ellipticity function of giant galaxy voids .
then , we incorporate the redshift distortion and galaxy bias effect into the analytic model of the void ellipticity function and fit it to the observational result by adjusting the value of the power - spectrum normalization with the help of the generalized @xmath0-minimization method .
the best - fit normalization of the linear power spectrum is found to be @xmath1 .
our result is higher than the wmap @xmath2-value but consistent with that from the recent work of liu and li who have constructed a new improved cmb map independently . .
And you have already written the first three sentences of the full article: the normalization amplitude of the linear matter power spectrum is one of the key cosmological parameters that are required to complete the theoretical description of the initial conditions of the universe @xcite .
it is often quantified in terms of @xmath2 , the rms fluctuations of the linear density field within a top - hat spherical radius @xmath3mpc .
various observables have so far been used to constrain the value of @xmath2 : the cluster abundance ( e.g. , * ? ? ?.
Please generate the next two sentences of the article | * ) , the weak lensing cosmic shear ( e.g. , * ? ? ?
* ) , strong lensing arc statistics ( e.g. , * ? ? ? |
3,107 | Suppose that you have an abstract for a scientific paper: rubber composites containing multi - walled carbon nanotubes have been irradiated with near infrared light to study their reversible photo - mechanical actuation response .
we demonstrate that the actuation is reproducible across differing polymer systems .
the response is directly related to the degree of uniaxial alignment of the nanotubes in the matrix , contracting the samples along the alignment axis .
the actuation stroke depends on the specific polymer being tested , however , the general response is universal for all composites tested .
we conduct a detailed study of tube alignment induced by stress and propose a model for the reversible actuation behavior , based on the orientational averaging of the local response .
the single phenomenological parameter of this model describes the response of an individual tube to adsorption of low - energy photons ; its experimentally determined value may suggest some ideas about such a response . .
And you have already written the first three sentences of the full article: many structures are able to change their mechanical properties and dimensions when an appropriate stimulus is applied .
this phenomenon is commonly called actuation . the energy from an external source triggers changes in the internal state of the system , leading to a mechanical response much larger than the initial input .
this ability to unlock internal work in a solid state structure is of key importance for many actuator applications ..
Please generate the next two sentences of the article | actuators with differing characteristics and mechanisms have been widely adopted by industry to fill a variety of technological requirements @xcite with some having a one - way response , while others providing an equilibrium , reversible response to the given stimulus .
shape - memory alloys @xcite or polymers @xcite are good examples of such smart actuating systems . however , in most cases a shape memory system works only in one direction , requiring a reset after the actuation . |
3,108 | Suppose that you have an abstract for a scientific paper: ranks of subspaces of vector spaces satisfy all linear inequalities satisfied by entropies ( including the standard shannon inequalities ) and an additional inequality due to ingleton .
it is known that the shannon and ingleton inequalities generate all such linear rank inequalities on up to four variables , but it has been an open question whether additional inequalities hold for the case of five or more variables . here
we give a list of 24 inequalities which , together with the shannon and ingleton inequalities , generate all linear rank inequalities on five variables . we also give a partial list of linear rank inequalities on six variables and general results which produce such inequalities on an arbitrary number of variables ; we prove that there are essentially new inequalities at each number of variables beyond four ( a result also proved recently by kinser ) .
[ theorem ] lemma [ theorem ] corollary [ theorem ] proposition [ theorem ] remark [ theorem ] algorithm [ theorem ] conjecture [ theorem ] example [ theorem ] definition .
And you have already written the first three sentences of the full article: it is well - known that the linear inequalities always satisfied by ranks of subspaces of a vector space ( referred to here as _ linear rank inequalities _ ) are closely related to the linear inequalities satisfied by entropies of jointly distributed random variables ( often referred to as _ information inequalities _ ) . for background material on this relationship and other topics used here , a useful source is hammer , romashchenko , shen , and vereshchagin @xcite .
the present paper is about linear rank inequalities ; nonetheless , the basic results from information theory will be useful enough that we choose to use the notation of information theory here .
we use the following common definitions : @xmath0 there are two interpretations of these equations ..
Please generate the next two sentences of the article | when @xmath1 , @xmath2 , and @xmath3 are random variables , @xmath4 denotes the joint random variable combining @xmath1 and @xmath2 ; @xmath5 is the entropy of @xmath1 ; @xmath6 is the entropy of @xmath1 given @xmath2 ; @xmath7 is the mutual information of @xmath1 and @xmath2 ; and @xmath8 is the mutual information of @xmath1 and @xmath2 given @xmath3 .
but when @xmath1 , @xmath2 , and @xmath3 denote subspaces of a vector space , then @xmath4 denotes the space spanned by @xmath1 and @xmath2 , which is @xmath9 or , since @xmath1 and @xmath2 are subspaces , just @xmath10 ; @xmath5 is the rank of @xmath1 ; @xmath6 is the excess of the rank of @xmath1 over that of @xmath11 ; @xmath7 is the rank of @xmath11 ; and @xmath8 is the excess of the rank of @xmath12 over that of @xmath3 . in either interpretation , |
3,109 | Suppose that you have an abstract for a scientific paper: fits images in the @xmath0 , @xmath1 , @xmath2 , @xmath3 , @xmath4 and @xmath5 passbands are presented of a sample of 86 face - on spiral galaxies .
the galaxies were selected from the ugc to have a diameter of at least 2 and a minor over major axis ratio larger than 0.625 .
the selected galaxies have an absolute galactic latitude @xmath6 , to minimize the effect of galactic extinction and foreground stars .
nearly all _ bvri _ data were obtained with the 1 m jacobus kapteyn telescope at la palma and the @xmath4 and @xmath5 data were obtained at the 3.8 m uk infra - red telescope at hawaii .
the field of view of the telescope / camera combinations were often smaller than the observed galaxies , therefore driftscanning and mosaicing techniques were employed to image at least along the major axis of the galaxies .
most images were obtained during photometric nights and calibrated using standard stars .
a small fraction of the images was calibrated from literature aperture photometry .
the azimuthally averaged radial luminosity profiles derived from these galaxy images ( see de jong and van der kruit @xcite , paper i ) are also made available in machine readable format , as are the results of the bulge / disk decompositions described in de jong ( @xcite , paper ii ) .
a detailed statistical analysis of the bulge and disk parameters of this data set can be found in de jong ( @xcite , paper iii ) .
the dust and stellar content of the galaxies as derived from the color profiles is described in de jong ( @xcite , paper iv ) .
evidence for secular evolution as found in this sample is shown in courteau , de jong and broeils ( @xcite ) .
* keywords : * surveys - galaxies : fundamental parameters - galaxies : photometry - galaxies : spiral - galaxies : structure .
And you have already written the first three sentences of the full article: a great deal about galaxy evolution can be learned by studying their broadband properties .
broadband observations give an immediate impression of the spectral energy distribution and thereby information on stellar and dust content .
even though integrated magnitudes of galaxies can be used to study global properties of galaxies , even more can be learned from examining the detailed distribution of their light and colors ..
Please generate the next two sentences of the article | the star formation history in galaxies seems to be related to their surface density properties ( kennicutt @xcite ; ryder and dopita @xcite ; de jong @xcite ) , and therefore it is imperative to have a statistical knowledge of surface brightness distributions in galaxies to understand galaxy evolution .
the image data set presented here was collected to study the surface brightness distribution of spiral galaxies . |
3,110 | Suppose that you have an abstract for a scientific paper: the problem of broadcasting a pair of correlated gaussian sources using optimal separate source and channel codes is studied .
considerable performance gains over previously known separate source - channel schemes are observed .
although source - channel separation yields suboptimal performance in general , it is shown that the proposed scheme is very competitive for any bandwidth compression / expansion scenarios .
in particular , for a high channel snr scenario , it can be shown to achieve optimal power - distortion tradeoff . .
And you have already written the first three sentences of the full article: consider the problem of transmitting two correlated gaussian sources over a gaussian broadcast channel with two receivers , each of which desires only to recover one of the sources . in @xcite
, it was proven that analog ( uncoded ) transmission , the simplest possible scheme , is actually optimal when the signal - to - noise ratio ( snr ) is below a threshold for the case of matched source and channel bandwidth . to solve the problem for other cases , various hybrid digital / analog ( hda ) schemes
have been proposed in @xcite , and @xcite ..
Please generate the next two sentences of the article | in fact , the hda scheme in @xcite achieves optimal performance for matched bandwidth whenever pure analog transmission does not , thereby leading to a complete characterization of the achievable power - distortion tradeoff . for the bandwidth - mismatch case ,
the hda schemes proposed in @xcite and @xcite comprise of different combinations of previous schemes using either superposition or dirty - paper coding . in all the aforementioned work , |
3,111 | Suppose that you have an abstract for a scientific paper: we have collected data for damped lyman@xmath0 ( dla ) systems , to investigate the chemical evolution of galaxies in the redshift interval @xmath1 . in doing that
, we have adopted the most general approach used so far to correct for dust depletion .
the best solution , obtained through @xmath2 minimization , gives as output parameters the global dla metallicity and the dust to metals ratio .
clear evolution of the metallicity vs. redshift is found ( 99.99% significance level ) , with average values going from @xmath3 solar at @xmath4 to @xmath5 solar at @xmath6 .
we also find that the majority of dlas ( @xmath7% ) shows dust depletion patterns which most closely resemble that of the warm halo clouds in the milky way , and have dust to metals ratios very close to warm halo clouds .
2@xmath8 # 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: many models of galaxy formation and evolution in recent years take as a reference for the observational side the results coming from qso absorption studies and in particular those objects that show a large hi column density , namely , the damped lyman@xmath0 systems ( dlas ) with @xmath9 atoms 2 ( see for example pei et al .
dlas have been widely studied both because they are believed to be the progenitors of present day galaxies and because the large hi column density allows one to probe the chemical enrichment problem .
dlas constitute so far the best laboratory where to directly measure the heavy element enrichment in a large interval of evolutionary phases , and to understand the processes of star formation and metal pollution of the universe ..
Please generate the next two sentences of the article | however , this kind of investigation requires a careful consideration of the effects of dust depletion suffered by dlas ( pei et al .
1991 ; pettini et al . |
3,112 | Suppose that you have an abstract for a scientific paper: we show how to use information about the equations defining secant varieties to smooth projective varieties in order to construct a natural collection of birational transformations .
these were first constructed as flips in the case of curves by m. thaddeus via geometric invariant theory , and the first flip in the sequence was constructed by the author for varieties of arbitrary dimension in an earlier paper .
we expose the finer structure of a second flip ; again for varieties of arbitrary dimension .
we also prove a result on the cubic generation of the secant variety and give some conjectures on the behavior of equations defining the higher secant varieties . .
And you have already written the first three sentences of the full article: in this paper we continue the geometric construction of a sequence of flips associated to an embedded projective variety begun in @xcite . we give hypotheses under which this sequence of flips exists , and state some conjectures on how positive a line bundle on a curve must be to satisfy these hypotheses .
these conjectures deal with the degrees of forms defining various secant varieties to curves and seem interesting outside of the context of the flip construction . as motivation
, we have the work of a. bertram and m. thaddeus . in @xcite this sequence of flips is constructed in the case of smooth curves via git , in the context of the moduli space of rank two vector bundles on a smooth curve ..
Please generate the next two sentences of the article | an understanding of this as a sequence of log flips is given in @xcite , and further examples of sequences of flips of this type , again constructed via git , are given in @xcite,@xcite .
our construction , however , does not use the tools of geometric invariant theory and is closer in spirit to @xcite,@xcite . in section [ review ] , we review the constructions in @xcite and @xcite and describe the relevant results from @xcite . in section [ genofsecants ] |
3,113 | Suppose that you have an abstract for a scientific paper: for a z - pinch geometry , we report on the nonlinear redistribution of free energy across scales perpendicular to the magnetic guide field , for a turbulent plasma described in the framework of gyrokinetics .
the analysis is performed using a local flux - surface approximation , in a regime dominated by electrostatic fluctuations driven by the entropy mode , with both ion and electron species being treated kinetically . to explore the anisotropic nature of the free energy redistribution caused by the emergence of zonal flows
, we use a polar coordinate representation for the field - perpendicular directions and define an angular density for the scale flux .
positive values for the classically defined ( angle integrated ) scale flux , which denote a direct energy cascade , are shown to be also composed of negative angular sections , a fact that impacts our understanding of the backscatter of energy and the way in which it enters the modeling of sub - grid scales for turbulence .
a definition for the flux of free energy across each perpendicular direction is introduced as well , which shows that the redistribution of energy in the presence of zonal flows is highly anisotropic . .
And you have already written the first three sentences of the full article: in plasma physics , turbulence is an underlying problem for numerous topics of research , ranging from the study of anomalous transport across magnetic surfaces in fusion relevant plasmas to the problem of plasma heating in astrophysical conditions .
one of the most identifiable characteristics of turbulence is the self - organization of turbulent structures .
mathematically , following a fourier decomposition , the nonlinear interactions between various scales of the system can be discerned ( here length scales being defined simply as @xmath0 ) and the self - organization of turbulence can be described in term of energy transfers and scale fluxes@xcite . while this methodology is primarily used in the case of homogenous isotropic turbulence , large scale motions like the zonal flows are captured by particular modes of the system . as these modes can lead to the development of an anisotropy that can affect the energy transfers and the scale fluxes ,.
Please generate the next two sentences of the article | expanding the definitions of various nonlinear based diagnostics becomes necessary for a better understanding of the underlying dynamics of the turbulent system and the subsequent development of models .
micro - turbulence in gradient driven magnetized plasmas represents one of the best examples where large structures in turbulence self - organize to give rise to zonal flows@xcite that in turn dominate the self - organization of smaller scales . since the turbulent structures in plasma reach scales much smaller than that of the ion gyroradius in the presence of a strong magnetic guide field , using the five - dimensional gyrokinetic ( gk ) formalism ( for which , due to the gyrokinetic ordering , the gyration phase of charged particles around the magnetic guide field has been removed consistently@xcite ) represents the most efficient method for the description of the problem@xcite . |
3,114 | Suppose that you have an abstract for a scientific paper: we report a precise measurement of the @xmath0 meson lifetime .
the data were taken by the selex experiment ( e781 ) spectrometer using 600 gev/@xmath1 @xmath2 , @xmath3 and @xmath4 beams .
the measurement has been done using 918 reconstructed @xmath0 .
the lifetime of the @xmath0 is measured to be @xmath5 fs , using @xmath6 and @xmath7 decay modes .
the lifetime ratio of @xmath8 to @xmath9 is @xmath10 .
( selex collaboration ) , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , .
And you have already written the first three sentences of the full article: precise measurements of the lifetimes of charm meson weak decays are important for understanding qcd in both perturbative and nonperturbative regimes . for mesons a joint expansion in heavy quark effective theory and perturbative qcd parameters treated through
the third order in the heavy quark mass shows a term including non - spectator w - annihilation as well as pauli interference .
the resulting non - leptonic decay rate differences between w - exchange in @xmath9 and w - annihilation in @xmath8 produce lifetime differences of order 10 - 20 % @xcite ..
Please generate the next two sentences of the article | the @xmath8 lifetime @xcite was dominated by the measurements from e687 collaboration ( 0.475 @xmath11 0.020 @xmath11 0.007 ps ) @xcite .
recently new precision measurements of the @xmath8 lifetime have been made by the e791 collaboration ( 0.518 @xmath11 0.014 @xmath11 0.007 ps ) @xcite and the cleo collaboration ( 486.3 @xmath11 15.0 @xmath12 fs ) @xcite . |
3,115 | Suppose that you have an abstract for a scientific paper: planets in close - in orbit interact with the magnetized wind of their hosting star .
this magnetic interaction was proposed to be a source for enhanced emissions in the chromosphere of the star , and to participate in setting the migration time - scale of the close - in planet .
the efficiency of the magnetic interaction is know to depend on the magnetic properties of the host star , of the planet , and on the magnetic topology of the interaction .
we use a global , three - dimensional numerical model of close - in star planet systems , based on the magnetohydrodynamics approximation , to compute a grid of simulations for varying properties of the orbiting planet . we propose a simple parametrization of the magnetic torque that applies to the planet , and of the energy flux generated by the interaction .
the dependancy upon the planet properties and the wind properties are clearly identified in the derived scaling laws , which can be used in secular evolution codes to take into account the effect of magnetic interactions in planet migration .
they can also be used to estimate a potential magnetic source of enhanced emissions in observed close - in star - planet systems , in order to constrain observationally possible exoplanetary magnetic fields . .
And you have already written the first three sentences of the full article: close - in giant planets are the most easily detected exoplanets today , as they are able to imprint significant radial velocities to their host star , and generate very clear transits . due to their proximity , the two main interactions with their host ( tides and magnetism , see * ? ? ?
* ) are very strong compared to the case of solar system planets . in theory , fast and efficient exchanges of angular momentum and energy between the planet and its host are hence possible in theses systems , altering their secular evolution . as a result
, significant efforts have been made in the past decades to look for observational signatures of these interactions , along with thorough theoretical research to better understand the physical mechanisms sustaining them ..
Please generate the next two sentences of the article | numerous puzzling observations of close - in systems have been recently reported .
periodic anomalous chromospheric emissions have been observed on star harbouring a close - in hot jupiter @xcite . |
3,116 | Suppose that you have an abstract for a scientific paper: these lectures include an introduction to the partonic description of the proton , the photon and the ` colour singlet ' , as seen in inclusive and semi - inclusive dis , in @xmath0 collisions , and in diffractive processes , respectively .
their formal treatment using structure , fragmentation , and fracture functions is outlined giving an insight into the perturbative qcd framework for these functions .
examples and comparisons with experimental data from lep , hera , and tevatron are also covered . .
And you have already written the first three sentences of the full article: the discovery of asymptotic freedom , one of the most significant properties of strong interactions embodied by quantum chromodynamics ( qcd ) opened , more than 25 years ago , a new chapter in our understanding of the structure of matter which has has been actively followed by theoreticians and experimentalists ever since .
the short distance structure of hadrons , together with the production of jets in hadronic collisions are paradigmatic among the strong interaction phenomena successfully accounted by qcd and even though the standing of the theory is today well established , further theoretical refinements and the corresponding experimental validation renew constantly the original enthusiasm of the high energy physics community .
these lectures intend to provide an overview of the more recent topics of high energy collisions related in a way or another to perturbative qcd ..
Please generate the next two sentences of the article | first we briefly remind the essentials of qcd , including the main features of partons ( the quarks and gluons ) , which are the true protagonists in the story . then
, we refer to what is known about the partonic structure of three of the main benchmarks of qcd , the proton , the photon , and the singlet colour or pomeron. finally we will try to draw the connections between their corresponding structures which in some way relate the physics made in the three main hep laboratories . as usual , many interesting and highly active topics have been excluded from the lectures in favor of a more detailed analysis of the covered points . |
3,117 | Suppose that you have an abstract for a scientific paper: using data samples collected at @xmath0 gev and @xmath1 gev by the besii detector at the bepc , the branching fraction of @xmath2 is measured to be @xmath3 \times 10^{-4}$ ] , and the relative branching fraction of @xmath4 to that of @xmath5 is measured to be @xmath6 \%$ ] via @xmath7 .
the electromagnetic form factor of @xmath8 is determined to be @xmath9 and @xmath10 at @xmath0 gev and @xmath1 gev , respectively . .
And you have already written the first three sentences of the full article: strong decays of @xmath11 to @xmath8 are suppressed , since the reaction violates g - parity conservation . in @xmath12
colliding beam experiments , @xmath8 may also be produced by @xmath13 ( called the `` continuum process '' hereafter ) .
it is expected that the continuum contribution is large and may contribute around 60% of the @xmath8 events at the @xmath11 energy ..
Please generate the next two sentences of the article | this contribution must be removed in determining @xmath14 , as has been described for the @xmath15 decay mode @xcite . in this analysis ,
data samples at the @xmath11 peak ( @xmath16 gev ) and off - resonance ( @xmath17 gev ) are used . |
3,118 | Suppose that you have an abstract for a scientific paper: the general characteristics based off - lattice boltzmann scheme ( bkg ) proposed by bardow et al .
, @xcite and the discrete unified gas kinetic scheme ( dugks ) @xcite are two methods that successfully overcome the time step restriction by the collision time , which is commonly seen in many other kinetic schemes . basically , the bkg scheme is a time splitting scheme , while the dugks is an un - split finite volume scheme . in this work ,
we first perform a theoretical analysis of the two schemes in the finite volume framework by comparing their numerical flux evaluations .
it is found that the effects of collision term are considered in the reconstructions of the cell - interface distribution function in both schemes , which explains why they can overcome the time step restriction and can give accurate results even as the time step is much larger than the collision time .
the difference between the two schemes lies in the treatment of the integral of the collision term , in which the bardow s scheme uses the rectangular rule while the dugks uses the trapezoidal rule .
the performance of the two schemes , i.e. , accuracy , stability , and efficiency are then compared by simulating several two dimensional flows , including the unsteady taylor - green vortex flow , the steady lid - driven cavity flow , and the laminar boundary layer problem .
it is observed that , the dugks can give more accurate results than the bkg scheme .
furthermore , the numerical stability of the bkg scheme decreases as the courant - friedrichs - lewy ( cfl ) number approaches to 1 , while the stability of dugks is not affected by the cfl number apparently as long as @xmath0 .
it is also observed that the bkg scheme is about one time faster than the dugks scheme with the same computational mesh and time step . .
And you have already written the first three sentences of the full article: the lattice boltzmann method ( lbm ) has become a popular numerical tool for flow simulations .
it solves the discrete velocity boltzmann equation ( dvbe ) with sophistically chosen discrete velocity set . with the coupled discretization of velocity space and spatial space ,
the numerical treatment of convection term reduces to a very simple _ streaming _ processes , which provides the benefits of low numerical dissipation , easy implementation , and high parallel computing efficiency ..
Please generate the next two sentences of the article | another advantage of lbm is that , the simplified collision term is computed implicitly while implemented explicitly , which allows for a large time step even though the collision term causess stiffness at a small relaxation time .
this advantage makes the lbm a potential solver for high reynolds number flows . |
3,119 | Suppose that you have an abstract for a scientific paper: we review the notion of symmetry breaking and restoration within the frame of nuclear energy density functional methods .
we focus on key differences between wave - function- and energy - functional - based methods .
in particular , we point to difficulties encountered within the energy functional framework and discuss new potential constraints on the underlying energy density functional that could make the restoration of broken symmetries better formulated within such a formalism .
we refer to ref .
@xcite for details . .
And you have already written the first three sentences of the full article: symmetries are essential features of quantal systems as they characterize their energetics and provide transition matrix elements of operators with specific selection rules . however , certain emergent phenomena relate to the spontaneous breaking of those symmetries @xcite
. in nuclear systems , such spontaneously - broken symmetries ( i ) relate to specific features of the inter - particle interactions , ( ii ) characterize internal correlations and ( iii ) leave clear fingerprints in the excitation spectrum of the system . in finite systems though , quantum fluctuations can not be ignored such that the concept of spontaneous symmetry breaking is only an intermediate description that arises within certain approximations .
eventually , symmetries must be restored to achieve a complete description of the system ..
Please generate the next two sentences of the article | in wave - function - based methods , the symmetry breaking step , e.g. the symmetry unrestricted hartree - fock - bogoliubov approximation , relies on minimizing the average value of the hamiltonian for a trial wave - function that does not carry good quantum numbers , i.e. which mixes irreducible representations of the symmetry group of interest .
restoring symmetries amounts to using an enriched trial wave - function that does carry good quantum numbers . |
3,120 | Suppose that you have an abstract for a scientific paper: we investigate the behavior of the magneto - rotational instability in the limit of extremely weak magnetic field , i.e. , as the ratio of ion cyclotron frequency to orbital frequency ( @xmath0 ) becomes small .
considered only in terms of cold two - fluid theory , instability persists to arbitrarily small values of @xmath0 , and the maximum growth rate is of order the orbital frequency except for the range @xmath1 , where it can be rather smaller . in this range ,
field aligned with rotation ( @xmath2 ) produces slower growth than anti - aligned field ( @xmath3 ) .
the maximum growth rate is generally achieved at smaller and smaller wavelengths as @xmath4 diminishes . when @xmath5 , new unstable
electromagnetic - rotational " modes appear that do not depend on the equilibrium magnetic field . because the most rapidly - growing modes have extremely short wavelengths when @xmath4 is small , they are often subject to viscous or resistive damping , which can result in suppressing all but the longest wavelengths , for which growth is much slower . we find that this sort of damping is likely to curtail severely the frequently - invoked mechanism for cosmological magnetic field growth in which a magnetic field seeded by the biermann battery is then amplified by the magneto - rotational instability . on the other hand , the small @xmath4 case may introduce interesting effects in weakly - ionized disks in which dust grains carry most of the electric charge . .
And you have already written the first three sentences of the full article: since its reintroduction into astrophysics by balbus & hawley ( 1991 ) , the magneto - rotational instability ( mri ) has become an essential ingredient in our understanding of astrophysical fluids in a state of differential rotation . as a result of its action , strong turbulence is created anywhere there is a weak magnetic field in a conducting fluid whose rotation rate decreases away from the rotation axis .
the turbulent magnetic ( and , to a lesser degree , fluid ) stress it creates is the most likely source of angular momentum transport in accretion disks ( balbus & hawley 1998 ) .
the joint action of turbulence and differential rotation can drive a dynamo capable of maintaining the magnetic energy at a few percent of the fluid internal energy ..
Please generate the next two sentences of the article | applications of these mechanisms have been found in a wide range of circumstances , from supernovae ( akiyama et al .
2003 ) to galaxies ( kim et al . |
3,121 | Suppose that you have an abstract for a scientific paper: we address the microscopic derivation of a quantum master equation in lindblad form for the dynamics of a massive test particle with internal degrees of freedom , interacting through collisions with a background ideal gas .
when either internal or centre of mass degrees of freedom can be treated classically , previously established equations are obtained as special cases .
if in an interferometric setup the internal degrees of freedom are not detected at the output , the equation can be recast in the form of a generalized lindblad structure , which describes non - markovian effects .
the effect of internal degrees of freedom on centre of mass decoherence is considered in this framework . .
And you have already written the first three sentences of the full article: in recent times major advances in the experimental techniques have led to the realization of experiments in which quantum systems in a single particle regime are studied under their controlled interaction with some environment . a paradigmatic example in this context
is given by the motion of a massive test particle in an interferometric setup , which gives rise to interference fringes as typical quantum signatures .
when the coupling with the environment becomes of relevance , such interference fringes are gradually washed out , and a classical dynamics is eventually recovered ..
Please generate the next two sentences of the article | this phenomenon goes under the name of decoherence @xcite .
its understanding and theoretical description require on the one hand a control over the environment , on the other hand a microscopic model for the interaction and the ensuing dynamics . for the case of a tracer particle immersed in a dilute gas |
3,122 | Suppose that you have an abstract for a scientific paper: a planar maxwell - chern - simons - proca model endowed with a lorentz - violating background is taken as framework to investigate the electron - electron interaction .
the dirac sector is introduced exhibiting a yukawa and a minimal coupling with the scalar and the gauge fields , respectively .
the the electron - electron interaction is then exactly evaluated as the fourier transform of the mller scattering amplitude ( carried out in the non - relativistic limit ) for the case of a purely time - like background .
the interaction potential exhibits a totally screened behavior far from the origin as consequence of massive character of the physical mediators . the total interaction ( scalar plus gauge potential )
can always be attractive , revealing that this model may lead to the formation of electron - electron bound states . .
And you have already written the first three sentences of the full article: in 1990 , carroll - field - jackiw @xcite have proposed a version of the maxwell electrodynamics corrected by a chern - simons - like term @xmath0 in order to incorporate a lorentz - violating background @xmath1 into the usual electrodynamics .
this term implies a modified theory in which photons with different polarizations propagate with distinct velocities ( birefringence ) .
some years later , colladay & kostelecky @xcite-@xcite have constructed an extension of the minimal standard model , the extended standard model ( sme ) , in which lorentz - violating tensor terms , stemming from a spontaneous symmetry breaking ( ssb ) of a more fundamental theory ( defined at the planck scale ) are properly incorporated in all interaction sectors . the construction of the sme was in part motivated by works demonstrating the possibility of lorentz and cpt spontaneous violation in the context of string theory @xcite-@xcite ..
Please generate the next two sentences of the article | recently , the sme has motivated innumerous interesting works @xcite-@xcite .
one of the most remarkable controversies involving lorentz violation deals with the radiative generation of the carroll - field - jackiw term from the integration on the fermion fields @xcite-@xcite . |
3,123 | Suppose that you have an abstract for a scientific paper: neste trabalho so referidas motivaes , aplicaes e relaes da teoria do controlo com outras reas da matemtica .
apresentamos uma breve resenha histrica sobre o controlo ptimo , desde as suas origens no clculo das variaes e na teoria clssica do controlo aos dias de hoje , dando especial destaque ao princpio do mximo de pontryagin .
* palavras chave : * controlo ptimo , princpio do mximo de pontryagin , aplicaes da teoria matemtica dos sistemas de controlo . .
And you have already written the first three sentences of the full article: todos ns j tentmos , numa ou outra ocasio , manter em equilbrio uma vara sobre o dedo indicador ( , resolver o problema do pndulo invertido ) .
por outro lado muito mais difcil , sobretudo se fecharmos os olhos , manter em equilbrio um pndulo invertido duplo .
a teoria do controlo permite faz - lo sob a condio de dispormos de um bom modelo matemtico ..
Please generate the next two sentences of the article | um sistema de controlo um sistema dinmico , que evolui no tempo , sobre o qual podemos agir atravs de uma funo de comando ou controlo .
um computador , que permite a um utilizador efectuar uma srie de comandos , um ecossistema sobre o qual podemos agir favorecendo esta ou aquela espcie , os tecidos nervosos que formam uma rede controlada pelo crebro e realizam a transformao de estmulos provenientes do exterior em aces do organismo , um robot que deve efectuar uma tarefa bem precisa , uma viatura sobre a qual agimos por intermdio de um pedal de acelerao , de travagem e embraiagem e que conduzimos com a ajuda de um volante , um satlite ou uma nave espacial , so todos eles exemplos de sistemas de controlo , os quais podem ser modelados e estudados pela teoria dos sistemas de controlo . a teoria do controlo analisa as propriedades de tais sistemas , com o intuito de os `` conduzir '' de um determinado estado inicial a um dado estado final , respeitando eventualmente certas restries . |
3,124 | Suppose that you have an abstract for a scientific paper: isoscaling and isobaric yield ratio parameters are compared from canonical and grand canonical ensembles when applied to multifragmentation of finite nuclei .
source dependence of isoscaling parameters & source and isospin dependence of isobaric yield ratio parameters are examined in the framework of the canonical and the grand canonical models .
it is found that as the nucleus fragments more , results from both the ensembles converge and observables calculated from the canonical ensemble coincide more with those obtained from the formulae derived using the grand canonical ensemble . .
And you have already written the first three sentences of the full article: the study of the nuclear equation of state is an important area of research in intermediate energy heavy ion reactions @xcite and results from nuclear multifragmentation reactions are extensively used for such study .
the statistical models are extremely powerful and widely used tools for study of the multifragmentation reactions . in models of statistical disassembly of a nuclear system formed by the collision of two heavy ions at intermediate energy one
assumes that the hot and compressed nuclear system expands and subsequently fragments into composites of different masses depending on the initial conditions ..
Please generate the next two sentences of the article | the fragmentation of the nucleus into available channels ( depends on phase space ) can be solved in different statistical ensembles ( microcanonical , canonical and grand canonical ) . for finite nuclei , in general the results for different observables
differ in different ensembles and they are found to converge under certain conditions @xcite . + isoscaling @xcite and isobaric yield ratio @xcite are two well known methods which are used to study the nuclear eos and to extract liquid drop model parameters ( symmetry energy coefficient for example ) from multifragmentation reactions . |
3,125 | Suppose that you have an abstract for a scientific paper: we present the final results from our deep hst imaging study of the host galaxies of radio - quiet quasars ( rqqs ) , radio - loud quasars ( rlqs ) and radio galaxies ( rgs ) .
we describe and analyze new wfpc2 @xmath0-band observations for 14 objects which , when combined with the first tranche of hst imaging reported in mclure et al ( 1999 ) , provide a complete and consistent set of deep , red , line - free images for statistically - matched samples of 13 rqqs , 10 rlqs and 10 rgs in the redshift band @xmath1 .
we also report the results of new deep vla imaging which has yielded a 5 ghz detection of all but one of the 33 agn in our sample .
careful modelling of our images , aided by a high dynamic - range point - spread function , has allowed us to determine accurately the morphology , luminosity , scale - length and axial ratio of _ every _ host galaxy in our sample .
armed with this information we have undertaken a detailed comparison of the properties of the hosts of these 3 types of powerful agn , both internally , and with the galaxy population in general .
we find that spheroidal hosts become more prevalent with increasing nuclear luminosity such that , for nuclear luminosities @xmath2 , the hosts of both radio - loud _ and _ radio - quiet agn are virtually all massive ellipticals .
moreover , we demonstrate that the basic properties of these hosts are indistinguishable from those of quiescent , evolved , low - redshift ellipticals of comparable mass .
this result rules out the possibility that radio - loudness is determined by host - galaxy morphology , and also sets severe constraints on evolutionary schemes which attempt to link low - z ulirgs with rqqs . instead
, we show that our results are as expected given the relationship between black - hole and spheroid mass established for nearby galaxies , and apply this relation to estimate the mass of the black hole in each object .
the results agree remarkably well with completely - independent estimates based on nuclear....
And you have already written the first three sentences of the full article: studies of the host galaxies of low - redshift quasars can enable us to define the subset of the present - day galaxy population which is capable of producing quasar - level nuclear activity .
this is of obvious importance for constraining physical models of quasar evolution ( small & blandford 1992 ; haehnelt & rees 1993 ; kauffman & haehnelt 2000 ) , and for exploring the connection between black - hole and galaxy formation ( silk & rees 1998 , fabian 1999 , franceschini et al .
1999 , granato et al ..
Please generate the next two sentences of the article | 2001 , kormendy & gebhardt 2001 ) .
such observations are also of value for testing unified models of radio - loud agn ( e.g. peacock 1987 , barthel 1989 , urry & padovani 1995 ) , constraining possible evolutionary links between ulirgs and quasars ( sanders & mirabel 1996 ) , exploring the origin of radio - loudness ( blandford 2000 ) , and as a means to estimate the masses of the central black holes which power the active nuclei ( mclure et al . |
3,126 | Suppose that you have an abstract for a scientific paper: in this article we analyze the resolvent , the heat kernel and the spectral zeta function of the operator @xmath0 over the finite interval .
the structural properties of these spectral functions depend strongly on the chosen self - adjoint realization of the operator , a choice being made necessary because of the singular potential present . only for the friedrichs realization standard properties
are reproduced , for all other realizations highly nonstandard properties are observed . in particular , for @xmath1 we find terms like @xmath2 in the small-@xmath3 asymptotic expansion of the heat kernel .
furthermore , the zeta function has @xmath4 as a logarithmic branch point . .
And you have already written the first three sentences of the full article: it is well - known that the zeta function of a laplacian over a smooth compact manifold , with or without boundary , defines a meromorphic function on @xmath5 with simple poles at prescribed half - integer values depending on the dimension of the manifold @xcite .
( for a manifold with boundary , we put local boundary conditions , e.g. dirichlet conditions . )
these properties have far reaching applications in physics as well as mathematics , e.g. in the context of casimir energies , effective actions and analytic torsion ; see , for example , @xcite ..
Please generate the next two sentences of the article | surprisingly , there is a completely natural example of a zeta function for which the described properties break down and which has no meromorphic extension to @xmath5 .
let @xmath6 be any compact region and take polar coordinates @xmath7 centered at any fixed point in @xmath8 . |
3,127 | Suppose that you have an abstract for a scientific paper: in this talk i review the recent progress on the numerical evaluation of the hadronic light - by - light contribution to the anomalous magnetic moment of the muon and i discuss the role of experimental data on the accuracy of its determination .
anomalous magnetic moment of the muon , hadronic light - by - light contribution .
And you have already written the first three sentences of the full article: the anomalous magnetic moment of the muon @xmath0 is one of the most accurately measured quantities in particle physics , and as such is a very promising signal of new physics if a deviation from its prediction in the standard model is found . the present experimental value for @xmath1 , is given by @xmath2 , as an average of @xmath3 and @xmath4 @xcite .
since statistical errors are the largest source of uncertainties , a proposal to measure it again to a precision of @xmath5 has recently been submitted to fnal @xcite and jparc @xcite , using different experimental techniques . at the level of the experimental accuracy
, the qed contributions has been completed up to the fifth order @xmath6 , giving the qed contribution @xmath7 @xcite , using the rydberg constant and the ratio @xmath8 as inputs @xcite ..
Please generate the next two sentences of the article | also electroweak ( ew ) and hadronic contributions are necessary .
the latter represents the main uncertainty in the standard model in terms of the hadronic vacuum polarization ( hvp ) and the hadronic light - by - light scattering ( hlbl ) . |
3,128 | Suppose that you have an abstract for a scientific paper: in this paper we introduce @xmath0-run overpartitions as natural analogs to partitions without @xmath0-sequences , which were first defined and studied by holroyd , liggett , and romik . following their work as well as that of andrews ,
we prove a number of results for @xmath0-run overpartitions , beginning with a double summation @xmath1-hypergeometric series representation for the generating functions . in the special case of @xmath2-run overpartitions
we further relate the generating function to one of ramanujan s mock theta functions .
finally , we describe the relationship between @xmath0-run overpartitions and certain sequences of random events , and use probabilistic estimates in order to determine the asymptotic growth behavior of the number of @xmath0-run overpartitions of size @xmath3 . .
And you have already written the first three sentences of the full article: a _ partition _ of a positive integer @xmath3 is a non - increasing sequence of positive integers whose sum is @xmath3 ; the number of distinct partitions of @xmath3 is traditionally denoted by @xmath4 . a _ sequence _ ( or _
run _ ) in a partition is any subsequence of consecutive integers that appear as parts .
integer partitions without sequences were first studied by macmahon in @xcite ..
Please generate the next two sentences of the article | he described their relationship to partitions with repeated parts , and also determined their generating series .
these partitions were studied more recently by holroyd , liggett , and romik in @xcite , where the authors introduced the general family of _ partitions without @xmath0-sequences _ for any @xmath5 , in which no @xmath0 consecutive integers may all appear as parts . |
3,129 | Suppose that you have an abstract for a scientific paper: we present improvements to the index - calculus algorithm for the computation of the ideal class group and regulator of a real quadratic field .
our improvements consist of applying the double large prime strategy , an improved structured gaussian elimination strategy , and the use of bernstein s batch smoothness algorithm .
we achieve a significant speed - up and are able to compute the ideal class group structure and the regulator corresponding to a number field with a 110-decimal digit discriminant . .
And you have already written the first three sentences of the full article: computing invariants of real quadratic fields , in particular the ideal class group and the regulator , has been of interest since the time of gauss , and today has a variety of applications . for example , solving the well - known pell equation is intimately linked to computing the regulator , and integer factorization algorithms have been developed that make use of this invariant .
public - key cryptosystems have also been developed whose security is related to the presumed difficulty of these computational tasks .
see @xcite for details ..
Please generate the next two sentences of the article | the fastest algorithm for computing the ideal class group and regulator in practice is a variation of buchmann s index - calculus algorithm @xcite due to jacobson @xcite .
the algorithm on which it is based has subexponential complexity in the size of the discriminant of the field . |
3,130 | Suppose that you have an abstract for a scientific paper: we derive the event - by - event likelihood that allows to extract the complete information contained in the energy , time and direction of supernova neutrinos , and specify it in the case of sn1987a data .
we resolve discrepancies in the previous literature , numerically relevant already in the concrete case of sn1987a data .
preprint : lngs / th-01/09 and cern - ph - th/2009 - 115 .
And you have already written the first three sentences of the full article: sn1987a neutrino events @xcite prompted many dedicated analyses .
even if the number of detected neutrinos is limited , these analyses provide interesting limits on neutrino properties and clues on the core collapse mechanism .
the question of which likelihood should be adopted for supernova neutrino data analysis will become crucial after the next galactic supernova , when a much larger number of neutrino events will be collected ..
Please generate the next two sentences of the article | these events will carry information on neutrino properties mixed with information about supernova properties , so that we will need to jointly study their energy , time and direction distributions to try to extract all the relevant pieces of information .
therefore it will remain unpractical to bin the events and an event - by - event likelihood will remain the best tool for data analysis . |
3,131 | Suppose that you have an abstract for a scientific paper: we study the transverse momentum spectra of fermions and bosons produced in strong , time - dependent abelian field .
the transverse size of the abelian field is finite , similarly to color strings and ropes .
different time - dependent field strengths are investigated in a kinetic model , and transverse momentum spectra are calculated for fermions and bosons .
these spectra display exponential or polynomial behavior at high @xmath0 , depending on the given time dependence .
we compare our spectra to lattice result for a classical gluon field and obtain surprisingly good agreement in certain cases . .
And you have already written the first three sentences of the full article: ultrarelativistic heavy ion collisions at sps and rhic energies ( @xmath1 agev ) provided an enormous volume of experimental data on particle production @xcite . the microscopic mechanisms of hadron production are not fully understood and many different descriptions coexist to explain these data .
transverse momentum spectra of produced hadrons have been measured in a wide momentum region ( e.g. @xmath2 gev at rhic ) , and can become a decisive test between different perturbative and non - perturbative models of hadron formation .
investigations of @xmath3 collisions at high energies led to the introduction of chromoelectric flux tube ( string ) models , where these tubes are connecting the quark and diquark constituents of colliding protons @xcite ..
Please generate the next two sentences of the article | strings are good examples of how to convert the kinetic energy of a collision into field energy .
when these flux tubes become unstable , new hadrons will be produced via quark - antiquark and diquark - antidiquark pair production . |
3,132 | Suppose that you have an abstract for a scientific paper: these lectures are intended to give a pedagogical introduction to the main current picture of the very early universe . after elementary reviews of general relativity and of the standard big bang model ,
the following subjects are discussed : inflation , the classical relativistic theory of cosmological perturbations and the generation of perturbations from scalar field quantum fluctuations during inflation .
p l .
And you have already written the first three sentences of the full article: the purpose of these lectures is to give an introduction to the present _ standard picture of the early universe _ , which _ complements _ the older standard big bang model .
these notes are intended for non - experts on this subject .
they start with a very short introduction to general relativity , on which modern cosmology is based , followed by an elementary review of the standard big bang model ..
Please generate the next two sentences of the article | we then discuss the limitations of this model and enter into the main subject of these lectures : _
inflation_. inflation was initially invented to solve some of the problems of the standard big bang model and to get rid of unwanted relics generically predicted by high energy models . |
3,133 | Suppose that you have an abstract for a scientific paper: it is shown that the vibrational wave packet relaxation of initially coherent ( displaced ) states as well as the quantum superposition of coherent states in heat bathes with the different spectral densities exhibit a number of peculiarities compared with the cases of linear phase - sensitive relaxation , quadratic relaxation , and relaxational dynamics described with the use of zurek s environmentally - induced pointer basis .
a strong dependence of the relaxation rate on the position of the spectral density maximum of the bath is found .
the differences can be used for the discrimination of the mechanisms of the molecule - environment interactions .
pacs number(s ) : 82.29.rp , 33.80.be , 32.80.bx , 31.70.hq .
And you have already written the first three sentences of the full article: the behavior of many quantum systems strongly depends on their interaction with the environment .
it is important to take this interaction into account to realistically describe systems like , e.g. , vibrational levels in a big molecule , the quantized mode of an electromagnetic field , or a trapped ion .
the rapid development of experimental techniques in these and other branches of physics and chemistry leads to an increased interest in theoretical descriptions of possible experiments by numerical calculations . additionally our calculations , which concern such systems , allow us to regard the still existing question about the border between classical and quantum effects from a new point of view ..
Please generate the next two sentences of the article | for the systems , which are described here , the border to disappearance of quantum effects has been estimated .
one of the fundamental questions of quantum physics is to understand why the general principle of superposition works very well in microscopic physics but leads to paradox situations in macroscopic physics such as the schrdinger cat paradox @xcite where the cat can exist in a superposition of the states dead and alive . |
3,134 | Suppose that you have an abstract for a scientific paper: if the universe is slightly non - extensive , and the distribution functions are not exactly given by those of boltzmann - gibbs , the primordial production of light elements will be non - trivially modified .
in particular , the principle of detailed balance ( pdb ) , of fundamental importance in the standard analytical analysis , is no longer valid , and a non - extensive correction appears .
this correction is computed and its influence is studied and compared with previous works , where , even when the universe was considered as an slightly non - extensive system , the pdb was assumed valid .
we analytically track the formation of helium and deuterium , and study the kind of deviation one could expect from the standard regime .
the correction to the capture time , the moment in which deuterium can no longer be substantially photo - disintegrated , is also presented .
this allows us to take into account the process of the free decay of neutrons , which was absent in all previous treatments of the topic .
we show that even when considering a first ( linear ) order correction in the quantum distribution functions , the final output on the primordial nucleosynthesis yields can not be reduced to a linear correction in the abundances .
we finally obtain new bounds upon the non - extensive parameter , both comparing the range of physical viability of the theory , and using the latest observational data .
= 10000 7.0 in -0.5 in -0.5 in -0.5 in .
And you have already written the first three sentences of the full article: primordial nucleosynthesis provides an interesting testing arena where to analyze the viability of physical theories , particularly , of the statistical description .
it is in this epoch where the earliest bounds upon a given theory with cosmological influence can be imposed .
thermal processes ( see ref ..
Please generate the next two sentences of the article | @xcite , hereafter referred as paper i ) are non - trivially modified by a non - extensive correction to quantum distribution functions .
then , different abundances of light elements are a possible outcome . |
3,135 | Suppose that you have an abstract for a scientific paper: we examine the influence of the excess of interstitial fe on the magnetic properties of fe@xmath0te compounds . because in iron chalcogenides the correlations are stronger than in the iron arsenides , we assume in our model that some of the fe orbitals give rise to localized magnetic moments . these moments
interact with each other via exchange interactions as well as phonon - mediated biquadratic interactions that favor a collinear double - stripe state , corresponding to the ordering vectors @xmath1 .
the remaining fe orbitals are assumed to be itinerant , giving rise to the first - principle derived fermi surface displaying nesting features at momenta @xmath2 .
increasing the amount of itinerant electrons due to excess fe , @xmath3 , leads to changes in the fermi surface and to the suppression of its nesting properties . as a result , due to the hund s coupling between the itinerant and localized moments
, increasing @xmath3 leads to modifications in the local moments exchange interactions via the multi - orbital generalization of the long - range ruderman - kittel - kasuya - yosida ( rkky ) interaction . by numerically computing the rkky corrections and minimizing the resulting effective exchange hamiltonian ,
we find , in general , that the excess electrons introduced in the system change the classical magnetic ground state from a double - stripe state to an incommensurate spiral , consistent with the experimental observations .
we show that these results can be understood as a result of the suppression of magnetic spectral weight of the itinerant electrons at momenta @xmath2 , combined with the transfer of broad magnetic spectral weight from large to small momenta , promoted by the introduction of excess fe . .
And you have already written the first three sentences of the full article: fe@xmath0te chalcogenides are the parent compounds of the simplest family of iron - based superconductors .
@xcite both the electronic and magnetic properties of fe@xmath0te compounds show strong sensitivity to the amount of non - stoichiometric fe ions . for small values of @xmath3 ,
the low - temperature crystal structure is monoclinic ( @xmath4 ) , and the magnetic order is described by the commensurate propagation vector @xmath5 , corresponding to a double - stripe pattern ..
Please generate the next two sentences of the article | this is remarkably different from feas - based parent compounds , which display an antiferromagnetic order described by @xmath6 or @xmath7 , corresponding to single - stripe patterns , and a crystal structure with orthorhombic symmetry ( @xmath8 ) .
experimentally , it is observed that by increasing the amount of interstitial fe , the magnetic structure of fe@xmath0te becomes an incommensurate spiral . |
3,136 | Suppose that you have an abstract for a scientific paper: the effective interaction between spherical colloids in nematic liquid crystals is investigated in the framework of the landau - de gennes theory .
the colloids differ through their interaction with the nematic . while both particles induce quadrupolar far - field distortions in the nematic matrix , with unlike quadrupole moments , one favours homeotropic and the other degenerate planar anchoring of the nematic director . in the strong anchoring regime
the colloids with homeotropic anchoring are accompanied by an equatorial disclination line defect , known as `` saturn - ring '' , while the colloids with degenerate planar anchoring nucleate a pair of antipodal surface defects , called `` boojums '' . in the linear ( large - distance ) regime
the colloidal interactions are of the quadrupolar type , where the quadrupoles have opposite signs .
these are attractive when the colloids are aligned either parallel or perpendicular to the far - field director . at short distance , non - linear effects including `` direct '' interactions between defects give rise to a repulsion between the particles , which prevents them from touching .
this finding supports the stability of nematic colloidal square crystallites the assembly of which has been reported recently . .
And you have already written the first three sentences of the full article: the self - assembly of colloidal particles into structures with controlled spatial ordering is of great importance in colloid science , with particular interest in the assembly of photonic crystals @xcite artificially produced periodic dielectric structures designed to control and manipulate light . in this context , a variety of colloidal structures assembled in liquid crystal ( lc ) matrices @xcite , combined with the unique mechanical and electro - optical properties of the lc host @xcite , have proven to be good candidates for the development of colloid crystals with tunable photonic properties . in conventional colloids , in isotropic fluids ,
the colloidal particles interact via van der waals , electrostatic , or steric forces .
these forces are isotropic , and their range does not exceed a few tens of nanometers ..
Please generate the next two sentences of the article | by contrast , when dispersed in a lc , due to its long - range orientational molecular ordering , colloidal particles interact predominantly through long - range anisotropic forces @xcite .
the origin of these effective forces is the elastic distortions of the lc matrix due to the presence of the colloidal particles . |
3,137 | Suppose that you have an abstract for a scientific paper: commercial cloud services have been increasingly supplied to customers in industry . to facilitate customers decision makings like cost - benefit analysis or cloud provider selection , evaluation of
those cloud services are becoming more and more crucial .
however , compared with evaluation of traditional computing systems , more challenges will inevitably appear when evaluating rapidly - changing and user - uncontrollable commercial cloud services .
this paper proposes an expert system for cloud evaluation that addresses emerging evaluation challenges in the context of cloud computing .
based on the knowledge and data accumulated by exploring the existing evaluation work , this expert system has been conceptually validated to be able to give suggestions and guidelines for implementing new evaluation experiments . as such , users can conveniently obtain evaluation experiences by using this expert system , which is essentially able to make existing efforts in cloud services evaluation reusable and sustainable .
= 5 expert system ; cloud computing ; commercial cloud service ; cloud services evaluation ; evaluation experiences .
And you have already written the first three sentences of the full article: since cloud computing has become increasingly accepted as one of the most promising computing paradigms in industry @xcite , providing cloud services also becomes an emerging business .
an increasing number of providers have started to supply commercial cloud services with different terminologies , definitions , and goals @xcite .
as such , evaluation of those cloud services would be crucial for many purposes ranging from cost - benefit analysis for cloud computing adoption to decision making for cloud provider selection ..
Please generate the next two sentences of the article | however , evaluation of commercial cloud services is different to and more challenging than that of other computing systems .
there are three main reasons for this : * in contrast with traditional computing systems , the cloud is relatively chaos @xcite . there is still a lack of standard definition of cloud computing , which inevitably leads to market hype and also skepticism and confusion @xcite . as a result , it is hard to point out the range of cloud computing , and not to mention a specific guideline to evaluate different commercial cloud services . consequently , although we have already learned rich lessons from the evaluation of traditional computing systems @xcite , it is still necessary to accumulate evaluation experiences in the cloud computing domain . |
3,138 | Suppose that you have an abstract for a scientific paper: we study a two parameter ( @xmath0 ) extension of the conformally invariant raise and peel model .
the model also represents a nonlocal and biased - asymmetric exclusion process with local and nonlocal jumps of excluded volume particles in the lattice .
the model exhibits an unusual and interesting critical phase where , in the bulk limit , there are an infinite number of absorbing states . in spite of these absorbing states
the system stays , during a time that increases exponentially with the lattice size , in a critical quasi - stationary state . in this critical phase
the critical exponents depend only on one of the parameters defining the model ( @xmath1 ) .
the endpoint of this critical phase belongs to a distinct universality class , where the system changes from an active to an inactive frozen state .
this new behavior we believe to be due to the appearance of jordan cells in the hamiltonian describing the time evolution .
the dimensions of these cells increases with the lattice size . in a special case ( @xmath2 )
where the model has no adsorptions we are able to calculate analytically the time evolution of some of the observables .
a polynomial time dependence is obtained due to the jordan cells structure of the hamiltonian . .
And you have already written the first three sentences of the full article: stochastic growth models of interfaces have been extensively studied along the years ( see @xcite for reviews ) .
the most studied universality class of critical dynamics behavior of growing interfaces are the ones represented by the edward - wilkinson ( ew ) @xcite and the kardar - parisi - zhang ( kpz ) @xcite models whose dynamical critical exponents are equal to 2 and @xmath3 , respectively . differently from these models , where the absorption and desorption processes are local , the raise and peel model ( rpm ) @xcite ,
although keeping the adsorption process local , the desorption processes is nonlocal ..
Please generate the next two sentences of the article | this model is quite interesting , as it is the first example of an stochastic model with conformal invariance .
the critical properties of the model depend on the parameter @xmath1 defined as the ratio among the adsorption and desorption rates . at @xmath4 |
3,139 | Suppose that you have an abstract for a scientific paper: we present the details of a deconstructed model that incorporates both higgsless and top - color mechanisms .
the model alleviates the tension between obtaining the correct top quark mass and keeping @xmath0 small that exists in many higgsless models .
it does so by singling out the top quark mass generation as arising from a yukawa coupling to an effective top - higgs which develops a small vacuum expectation value , while electroweak symmetry breaking results largely from a higgsless mechanism . as a result ,
the heavy partners of the sm fermions can be light enough to be seen at the lhc .
after presenting the model , we detail the phenomenology , showing that for a broad range of masses , these heavy fermions are discoverable at the lhc . .
And you have already written the first three sentences of the full article: understanding the mechanism of electroweak symmetry breaking ( ewsb ) is one of the most exciting problems facing particle physics today . the standard model ( sm ) , though phenomenologically successful , relies crucially on the existence of a scalar particle , the higgs boson @xcite , which has not been discovered in collider experiments . over the last few years ,
higgsless models @xcite have emerged as a novel way of understanding the mechanism of ewsb without the presence of a scalar particle in the spectrum . in an extra dimensional context , these can be understood in terms of a @xmath1 gauge theory in the bulk of a finite @xmath2 spacetime @xcite , with symmetry breaking encoded in the boundary conditions of the gauge fields .
these models can be thought of as dual to technicolor models , in the language of the ads / cft correspondence @xcite ..
Please generate the next two sentences of the article | one can understand the low energy properties of such theories in a purely four dimensional picture by invoking the idea of deconstruction @xcite .
the `` bulk '' of the extra dimension is then replaced by a chain of gauge groups strung together by non linear sigma model fields . |
3,140 | Suppose that you have an abstract for a scientific paper: experimental data as a stereo photographs from the 2 m propane bubble chamber lhe , jinr have been analyzed for exotic multibaryon metastable and stable states searches .
a number of peculiarities were found in the effective mass spectra of : 1)@xmath0,@xmath1 , @xmath2 , @xmath3 , @xmath4,@xmath5 and @xmath6 subsystems .
the observed well known @xmath7(1385),@xmath8 and @xmath9(892)resonances are good tests for this method . the width of @xmath10 for p+a reaction is two time larger than that presented in pdg . the @xmath11 spectrum observed enhancement in mass range of 1345 mev/@xmath12 which interpreted as a stopped in nucleus @xmath13 .
the cross section of stopped @xmath13 production is @xmath14 8 times larger than obtained by fritiof model with same experimental conditions .
= 11.6pt .
And you have already written the first three sentences of the full article: there are a few actual problems of nuclear and particle physics which are concerning subject of this report@xcite-@xcite .
these are following : in - medium modification of hadrons , the origin of hadron masses , the restoration of chiral symmetry , the confinement of quarks in hadrons , the structure of neutron stars .
strange multi - baryonic clusters are an exiting possibility to explore the properties of cold dense baryonic matter and non - perturbative qcd ..
Please generate the next two sentences of the article | multi - quark states , glueballs and hybrids have been searched for experimentally for a very long time , but none is established
the full experimental information of more than 700000 stereo photographs are used to select of events by @xmath15 [email protected] momentum resolution charged particles are found to be @xmath162.1 % for stopped particles and @xmath17=9.8 % , for nonstopped particles . |
3,141 | Suppose that you have an abstract for a scientific paper: we establish a procedure to find the extremal density matrices for any finite hamiltonian of a qudit system .
these extremal density matrices provide an approximate description of the energy spectra of the hamiltonian . in the case of restricting the extremal density matrices by pure states ,
we show that the energy spectra of the hamiltonian is recovered for @xmath0 and @xmath1 .
we conjecture that by means of this approach the energy spectra can be recovered for the hamiltonian of an arbitrary finite qudit system . for a given qudit system hamiltonian , we find new inequalities connecting the mean value of the hamiltonian and the entropy of an arbitrary state . we demonstrate that these inequalities take place for both the considered extremal density matrices and generic ones . .
And you have already written the first three sentences of the full article: recently @xcite an approach was established to study the ground state properties of algebraic hamiltonians .
this approach follows closely the algorithm established in @xcite . in particular , the approach was applied to describe the ground state of even even nuclei within the interacting boson model @xcite . in quantum optics ,
the procedure was used to determine the phase diagrams of the transitions between the normal regime to the super - radiant behavior of the ground states of two- and three - level systems interacting with a one - mode radiation field @xcite ..
Please generate the next two sentences of the article | this approach evaluates the mean value of the hamiltonian with respect to variational test coherent states associated to the corresponding algebraic structures of the hamiltonian .
there exists a tomographic approach , which also uses mean values of density operators in an ensemble of bases to get information on the state of the system @xcite . for continuous variables , |
3,142 | Suppose that you have an abstract for a scientific paper: we present the update of the unitarity triangle ( ut ) analysis within the standard model ( sm ) and beyond . within the sm , combining the direct measurements on sides and angles , the ut turns out to be overconstraint in a consistent way , showing that the ckm matrix is the dominant source of flavour mixing and cp - violation and that new physics ( np ) effects can appear at most as small corrections to the ckm picture . generalizing the ut analysis to investigate np effects , constraints on @xmath0 transitions
are also included and both ckm and np parameters are fitted simultaneously . while no evidence of np effects is found in @xmath1-@xmath2 and @xmath3-@xmath4 mixing , in the @xmath5-@xmath6 mixing an hint of np
is found at the @xmath7 level .
the ut analysis beyond the sm also allows us to derive bounds on the coefficients of the most general @xmath8 effective hamiltonian , that can be translated into bounds on the np scale .
ckm matrix 12.15.hh .
And you have already written the first three sentences of the full article: we present in this section the update of the unitarity triangle ( ut ) analysis within the standard model ( sm ) , performed by the utfit collaboration following the method described in refs .
the constraints used in the analysis can be distinguished in side and angle constraints , where the latter do not rely on theoretical calculations of hadronic matrix elements .
the side constraints come from the measurement of direct cp - violation in the kaon sector ( @xmath9 ) , of @xmath3 and @xmath5 mixing ( @xmath10 , @xmath11 ) and of semileptonic b decays ( @xmath12 ) ..
Please generate the next two sentences of the article | the angle constraints are cp - violating measurements for the @xmath3-system , performed with high statistics at b - factories : @xmath13 , @xmath14 , @xmath15 , @xmath16 , and @xmath17 . as shown in fig .
[ fig : sm_allconstr ] , the ckm matrix turns out to be consistently overconstraint . |
3,143 | Suppose that you have an abstract for a scientific paper: we study theoretically the spatial correlations between the intensities measured at the input and output planes of a disordered scattering medium .
we show that at large optical thicknesses , a long - range spatial correlation persists and takes negative values . for small optical thicknesses ,
short - range and long - range correlations coexist , with relative weights that depend on the optical thickness .
these results may have direct implications for the control of wave transmission through complex media by wavefront shaping , thus finding applications in sensing , imaging and information transfer . .
And you have already written the first three sentences of the full article: the study of wave scattering in disordered media is an active field of research , stimulated both by innovative applications in imaging and sensing @xcite and by fundamental questions in mesoscopic physics @xcite . in the last few years
, the possibility to control the propagation of optical waves in complex media in the multiple scattering regime has been demonstrated using wavefront shaping techniques @xcite .
this breakthrough offers new perspectives for imaging and communication through complex media @xcite ..
Please generate the next two sentences of the article | the initial schemes make use of optimization techniques requiring intensity measurements in the transmitted speckle , which in terms of practical applications is a serious drawback .
finding a way to control the transmission and focusing of light through a strongly scattering medium from measurements of the reflected speckle only is an issue of tremendous importance . |
3,144 | Suppose that you have an abstract for a scientific paper: essential to the description of a quantum system are its local degrees of freedom , which enable the interpretation of subsystems and dynamics in the hilbert space . while a choice of local tensor factorization of the hilbert space is often implicit in the writing of a hamiltonian or lagrangian ,
the identification of local tensor factors is not intrinsic to the hilbert space itself .
instead , the only basis - invariant data of a hamiltonian is its spectrum , which does not manifestly determine the local structure .
this ambiguity is highlighted by the existence of dualities , in which the same energy spectrum may describe two systems with very different local degrees of freedom .
we argue that in fact , the energy spectrum alone almost always encodes a unique description of local degrees of freedom when such a description exists , allowing one to explicitly identify local subsystems and how they interact . in special cases ,
multiple dual local descriptions can be extracted from a given spectrum , but generically the local description is unique .
5cm(12.5cm,-8 cm ) .
And you have already written the first three sentences of the full article: quantum systems are usually described by a hilbert space , a state vector , and a hamiltonian .
do these structures alone fully characterize a physical system ? without specifying more information , like a preferred choice of basis , it is difficult to make sense of the hamiltonian or the state .
for example , consider the one - dimensional ising model , with hamiltonian @xmath0 the hamiltonian clearly describes a chain of locally coupled two - level systems ..
Please generate the next two sentences of the article | this interpretation is possible because the expression for the hamiltonian implicitly includes a partition of the total hilbert space into subsystems using a tensor product factorization , @xmath1 this choice of tensor product structure " ( tps ) allows one to write the hamiltonian simply in terms of local operators .
however , if one does not specify a tps but instead writes the hamiltonian as a large matrix in some arbitrary basis , the system becomes difficult to interpret . |
3,145 | Suppose that you have an abstract for a scientific paper: we investigate the evolution of quasi - static stray electric fields in a linear paul trap over a period of several months .
depending on how these electric fields are initially induced we observe very different time scales for the field drifts .
photo - induced electric fields decay on time scales of days .
we interpret this as photo - electrically generated charges on insulating materials which decay via discharge currents .
in contrast , stray fields due to the exposure of the ion trap to a beam of ba atoms mainly exhibit slow dynamics on the order of months .
we explain this observation as a consequence of a coating of the trap electrodes by the atomic beam .
this may lead to contact potentials which can slowly drift over time due to atomic diffusion and chemical processes on the surface . in order not to perturb the field evolutions
, we suppress the generation of additional charges and atomic coatings in the paul trap during the measurements . for this
, we shield the ion trap from ambient light and only allow the use of near - infrared lasers .
furthermore , we minimize the flux of atoms into the ion trap chamber .
long - term operation of our shielded trap led us to a regime of very low residual electric field drifts of less than 0.03@xmath0v / m per day . .
And you have already written the first three sentences of the full article: paul traps have become essential tools in widely different fields of research ranging from quantum information@xmath0@xcite and quantum simulation@xmath0@xcite to precision metrology@xmath0@xcite and cold collisions between ions and neutrals@xmath0@xcite .
the further development of all these lines of research hinges on continuing improvements of the paul trap architectures and on a better understanding of the current experimental issues .
+ ideally , a single ion in a paul trap is only subjected to the electric fields generated by the voltages applied to the trap electrodes . however , even small spatial variations of the electrode surface potential ( i.e. patch potentials ) in the vicinity of the trap center create stray electric fields which significantly perturb this ideal configuration ..
Please generate the next two sentences of the article | this leads to undesired experimental complications .
quasi - static stray fields lead to positional shifts of the trapped ion@xmath0@xcite and thus to excess micromotion@xmath0@xcite . rapidly fluctuating stray fields |
3,146 | Suppose that you have an abstract for a scientific paper: in this work we study the radiative leptonic decays of @xmath0 , @xmath1 and @xmath2 , including both the short - distance and long - distance contributions .
the short - distance contribution is calculated by using the relativistic quark model , where the bound state wave function we used is that obtained in the relativistic potential model .
the long - distance contribution is estimated by using vector meson dominance model
. 0.25 cm .
And you have already written the first three sentences of the full article: the mechanism of heavy meson decays is one of the most interesting and challenging fields in particle physics , it involves both strong and weak interactions .
nowadays strong interaction in the non - perturbative region is still an unsolved problem .
compared with hadronic decays , leptonic decay is simpler ..
Please generate the next two sentences of the article | strong interaction only occurs within the initial particle .
pure - leptonic decay of heavy meson can be used to determine the decay constant , which describes the possibility - amplitude for the quark - untiquark emerging at the same point . |
3,147 | Suppose that you have an abstract for a scientific paper: if an absolute reference frame with respect to time , position , or orientation is missing one can only implement quantum operations which are covariant with respect to the corresponding unitary symmetry group @xmath0 . extending observations of vaccaro et al
. , i argue that the free energy of a quantum system with @xmath0-invariant hamiltonian then splits up into the holevo information of the orbit of the state under the action of @xmath0 and the free energy of its orbit average .
these two kinds of free energy can not be converted into each other .
the first component is subadditive and the second superadditive ; in the limit of infinitely many copies only the usual free energy matters . refined splittings of free energy into more than two independent ( non - increasing ) terms can be defined by averaging over probability measures on @xmath0 that differ from the haar measure . even in the presence of a reference frame ,
these results provide lower bounds on the amount of free energy that is lost after applying a covariant channel .
if the channel properly decreases one of these quantities , it decreases the free energy necessarily at least by the same amount , since it is unable to convert the different forms of free energies into each other .
begintheorem#1#2 opargbegintheorem#1#2#3 beginlemma#1#2 opargbeginlemma#1#2#3 begindefinition#1#2 opargbegindefinition#1#2#3 begincorollary#1#2 opargbegincorollary#1#2#3 beginexample#1#2 opargbeginexample#1#2#3 .
And you have already written the first three sentences of the full article: free energy is among the most important concepts of thermodynamics since it formalizes the fact that the usability of energy resources depends also on their _ entropy_. roughly speaking
, the idea is that in an energy conversion process the target system should typically be provided with energy without transferring entropy ( like increasing the kinetic of potential energy or a macroscopic body , for instance ) .
therefore , the worth of a system for being an energy source depends on the question to what extent one can extract energy from it without releasing too much entropy @xmath1 since the transfer of the dispensable entropy to the environment requires the additional amount @xmath2 of energy ( here @xmath3 is boltzmann s constant and @xmath4 is the temperature of the heat reservoir where the entropy is transferred to , e.g. , the environment ) . hence the amount of work that can be extracted from a physical system is not given by its inner energy ..
Please generate the next two sentences of the article | instead , it depends also on the entropy and on a fixed reference temperature , namely the temperature of the environment which is potentially used as an entropy sink .
conversely , a system that has no inner energy at all ( like a degenerate two - level system ) can be used to extract energy from the environment if its physical state is not the maximal entropy state . in other words , _ information _ can directly be used to extract work from the surrounding heat bath @xcite . |
3,148 | Suppose that you have an abstract for a scientific paper: in this paper we relate a problem in representation theory the study of yetter - drinfeld modules over certain braided hopf algebras to a problem in two - dimensional quantum field theory , namely the identification of integrable perturbations of a conformal field theory . a prescription that parallels
lusztig s construction allows one to read off the quantum group governing the integrable symmetry . as an example
, we illustrate how the quantum group for the loop algebra of @xmath0 appears in the integrable structure of the perturbed uncompactified and compactified free boson . zmp - hh/12 - 23 + hamburger beitrge zur mathematik 455 3em integrable perturbations of conformal field theories + and yetter - drinfeld modules 2em david bcher and ingo runkel + [email protected] , [email protected] + fachbereich mathematik , universitt
hamburg + bundesstrae 55 , 20146 hamburg , germany 2em november 2012 2em .
And you have already written the first three sentences of the full article: there are three main methods to investigate integrable field theories : factorised scattering , lattice discretisations , and perturbations around a cft .
we will be concerned with the latter , building on the approach of @xcite and its formulation and generalisation in terms of perturbed defects in @xcite .
the key ingredient in our construction are one - dimensional objects in the two - dimensional cft called _.
Please generate the next two sentences of the article | defect lines_. at such a defect line , the fields of the cft may have singularities or discontinuities .
for the particular type of defect we are interested in , the so - called _ topological defects _ , the fields may be discontinuous but not singular and the stress tensor remains continuous across the defect line . |
3,149 | Suppose that you have an abstract for a scientific paper: if all the supersymmetry particles ( sparticles ) except a light higgs boson are too heavy to be directly produced at the large hadron collider ( lhc ) and tevatron , a possible way to reveal evidence for supersymmetry is through their virtual effects in other processes .
we examine such supersymmetric qcd effects in bottom pair production associated with a light higgs boson at the lhc and tevatron .
we find that if the relevant sparticles ( gluinos and squarks ) are well above the tev scale , too heavy to be directly produced , they can still have sizable virtual effects in this process . for large @xmath0 , such residual effects can alter the production rate by as much as 40 percent , which should be observable in future measurements of this process .
= # 1,nucl . phys .
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b * # 1 * , # 1,phys .
rev .
d * # 1 * , # 1,phys .
rev .
lett . *
# 1 * , # 1,z .
phys .
c * # 1 * , # 1#20.5ex .
And you have already written the first three sentences of the full article: searching for the higgs boson is one of the most important tasks in particle physics .
the existence of a relatively light higgs is suggested by high precision fits to the data in the standard model ( sm ) and also is theoretically favored in the minimal supersymmetric standard model ( mssm ) @xcite .
verification of the existence of a light higgs boson at the lhc or tevatron is therefore a very important test for both the sm and the mssm . among the various production channels for a light higgs boson at the hadron colliders.
Please generate the next two sentences of the article | , the production in association with a bottom quark pair , @xmath1 , plays an important role in testing the bottom quark yukawa couplings .
while this process has a small cross section in the sm , in the mssm this production mechanism can be a significant source of higgs bosons since the bottom quark yukawa coupling in the mssm is proportional to @xmath0 ( defined as @xmath2 with @xmath3 being the vacuum expectation values of the two higgs doublets ) and the current analyses favor large @xmath0 . |
3,150 | Suppose that you have an abstract for a scientific paper: democratic societies are built around the principle of free and fair elections , that each citizen s vote should count equal .
national elections can be regarded as large - scale social experiments , where people are grouped into usually large numbers of electoral districts and vote according to their preferences .
the large number of samples implies certain statistical consequences for the polling results which can be used to identify election irregularities . using a suitable data collapse
, we find that vote distributions of elections with alleged fraud show a kurtosis of hundred times more than normal elections on certain levels of data aggregation . as an example
we show that reported irregularities in recent russian elections are indeed well explained by systematic ballot stuffing and develop a parametric model quantifying to which extent fraudulent mechanisms are present .
we show that if specific statistical properties are present in an election , the results do not represent the will of the people .
we formulate a parametric test detecting these statistical properties in election results .
remarkably , this technique produces similar outcomes irrespective of the data resolution and thus allows for cross - country comparisons .
free and fair elections are the cornerstone of every democratic society @xcite .
a central characteristic of elections being free and fair is that each citizen s vote counts equal .
however , already joseph stalin believed that `` it s not the people who vote that count ; it s the people who count the votes . ''
how can it be distinguished whether an election outcome represents the will of the people or the will of the counters ?
elections can be seen as large - scale social experiments .
a country is segmented into a usually large number of electoral units .
each unit represents a standardized experiment where each citizen articulates his / her political preference via a ballot .
although elections are one of the central pillars of a fully....
And you have already written the first three sentences of the full article: countries were selected by data availability . for each country we require availability of at least one aggregation level where the average population per territorial unit @xmath0 . this limit for @xmath1
was chosen to include a large number of countries , that have a comparable level of data resolution .
we use data from recent parliamentary elections in austria , canada , czech republic , finland , russia ( 2011 ) , spain and switzerland , the european parliament elections in poland and presidential elections in the france , romania , russia ( 2012 ) and uganda . here.
Please generate the next two sentences of the article | we refer by `` unit '' to any incarnation of an administrative boundary ( such as districts , precincts , wards , municipals , provinces , etc . ) of a country on any aggregation level .
if the voting results are available on different levels of aggregation , we refer to them by roman numbers , i.e. poland - i refers to the finest aggregation level for poland , poland - ii to the second finest , and so on . for each unit on each aggregation level for each country |
3,151 | Suppose that you have an abstract for a scientific paper: we investigate the fusion barriers for reactions involving ca isotopes @xmath0 , @xmath1 , and @xmath2 using the microscopic time - dependent hartree - fock theory coupled with a density constraint . in this formalism
the fusion barriers are directly obtained from tdhf dynamics .
we also study the excitation of the pre - equilibrium gdr for the @xmath1 system and the associated @xmath3-ray emission spectrum .
fusion cross - sections are calculated using the incoming - wave boundary condition approach .
we examine the dependence of fusion barriers on collision energy as well as on the different parametrizations of the skyrme interaction .
= 10000 = 10000 = 10000 .
And you have already written the first three sentences of the full article: the microscopic study of nuclear many - body problem and the understanding of the nuclear interactions that reproduce the observed structure and reaction properties are the underlying challenges of low energy nuclear physics . in this context ,
detailed investigations of the fusion process will lead to a better understanding of the interplay among the strong , coulomb , and weak interactions as well as the enhanced correlations present in these many - body systems .
recently , particular experimental attention has been given to fusion reactions involving ca isotopes @xcite ..
Please generate the next two sentences of the article | these new experiments supplemented the older fusion data @xcite and extended it to lower sub - barrier energies .
comparison of the sub - barrier cross - sections with those calculated using standard coupled - channel calculations suggested a hindrance of the fusion cross - sections at deep sub - barrier energies @xcite . |
3,152 | Suppose that you have an abstract for a scientific paper: we study the coupling between backward- and forward - propagating wave modes , with the same group velocity , in a composite right / left - handed nonlinear transmission line . using an asymptotic multiscale expansion technique ,
we derive a system of two coupled nonlinear schrdinger equations governing the evolution of the envelopes of these modes .
we show that this system supports a variety of backward- and forward propagating vector solitons , of the bright - bright , bright - dark and dark - bright type .
performing systematic numerical simulations in the framework of the original lattice that models the transmission line , we study the propagation properties of the derived vector soliton solutions .
we show that all types of the predicted solitons exist , but differ on their robustness : only bright - bright solitons propagate undistorted for long times , while the other types are less robust , featuring shorter lifetimes . in all cases ,
our analytical predictions are in a very good agreement with the results of the simulations , at least up to times of the order of the solitons lifetimes .
= 1 .
And you have already written the first three sentences of the full article: left - handed ( lh ) metamaterials are artificial , effectively homogeneous structures , featuring negative refractive index at specific frequency bands where the effective permittivity @xmath0 and permeability @xmath1 are simultaneously negative @xcite .
in fact , all known realizations of lh metamaterials rely on the use of common right - handed ( rh ) elements and , thus , in a realistic situation such a composite material features both a lh and a rh behavior , in certain frequency bands . physically speaking , the difference between the two is that in the lh ( rh ) regime , the energy and the wave fronts of the electromagnetic ( em ) waves propagate in the opposite ( same ) directions , giving rise to backward- ( forward- ) propagating waves .
transmission line ( tl ) theory constitutes a convenient framework for the analysis of lh metamaterials ..
Please generate the next two sentences of the article | such an analysis relies on the connection of the em properties of the medium ( @xmath0 and @xmath1 ) with the electric elements of the tl s unit cell , namely the serial and shunt impedance . as mentioned above , in practice _
composite right / left - handed ( crlh ) _ structures are quite relevant , giving rise to pertinent crlh - tl models . |
3,153 | Suppose that you have an abstract for a scientific paper: using the sswl database of syntactic parameters of world languages , and the mit media lab data on language interactions , we construct a spin glass model of language evolution .
we treat binary syntactic parameters as spin states , with languages as vertices of a graph , and assigned interaction energies along the edges .
we study a rough model of syntax evolution , under the assumption that a strong interaction energy tends to cause parameters to align , as in the case of ferromagnetic materials .
we also study how the spin glass model needs to be modified to account for entailment relations between syntactic parameters .
this modification leads naturally to a generalization of potts models with external magnetic field , which consists of a coupling at the vertices of an ising model and a potts model with @xmath0 , that have the same edge interactions .
we describe the results of simulations of the dynamics of these models , in different temperature and energy regimes .
we discuss the linguistic interpretation of the parameters of the physical model . .
And you have already written the first three sentences of the full article: the evolution of languages through the interaction of their speakers is a topic of interest to computational linguists and , like many interacting many - body problems , is difficult to study analytically . in this paper
we follow an approach that views languages at the level of syntax , with syntactic structures encoded as a string of binary syntactic parameters , a point of view originating in the principles and parameters model of generative linguistics , @xcite , @xcite ( see also @xcite for a more expository account ) .
it is known that syntactic parameters can change in the course of language evolution ..
Please generate the next two sentences of the article | cases of parameter flipping have been identified in the historical development of some indo - european languages , see for example @xcite . for recent results on language evolution from the point of view of syntactic parameters ,
see @xcite . |
3,154 | Suppose that you have an abstract for a scientific paper: a theory of reciprocating contacts for linear viscoelastic materials is presented .
results are discussed for the case of a rigid sphere sinusoidally driven in sliding contact with a viscoelastic half - space .
depending on the size of the contact , the frequency and amplitude of the reciprocating motion , and on the relaxation time of the viscoelastic body , we establish that the contact behavior may range from the steady - state viscoelastic solution , in which traction forces always oppose the direction of the sliding rigid punch , to a more elaborate trend , never observed before , which is due to the strong interaction between different regions of the path covered during the reciprocating motion .
practical implications span a number of applications , ranging from seismic engineering to biotechnology .
pacs numbers : : 62.20.qp , 46.55.+d . , 46.35.+z . .
And you have already written the first three sentences of the full article: the mechanics and physics of soft materials are intrinsically complex due to the strongly time - dependent and usually non - linear constitutive stress - strain relations that govern their response .
further intricacy is added when soft bodies are brought into contact and the problem is exacerbated by the geometry of the intimately mating surfaces . in the last two decades , the continuously growing technological relevance of engineering applications involving polymeric materials and soft tissues _ _ _ _ has generated enormous interest in the scientific community and has contributed to a leap in the number of publications in the field gorb , bio3,vertebrae ; these span investigations performed across the scales , from macroscopic to atomistic levels , and include analytical hunter , persson2001 numerical @xcite and experimental @xcite studies .
surprisingly , in spite of these vast research efforts , our understanding of soft matter problems is definitely far from being complete . in this paper , we focus our attention on an issue that has been systematically ignored but has a crucial importance : the reciprocating contact of viscoelastic materials , where the relative motion between the contacting bodies is periodically inverted . indeed , researchers have almost universally developed models to investigate unidirectional steady - state sliding between two mating surfaces made of viscoelastic material persson2001,carboneputignano ..
Please generate the next two sentences of the article | however , steady - state assumption can not be considered a universally valid condition .
there is a countless variety of engineering applications , ranging from the macro- to the nano- scales , where a periodic inversion of the motion direction is present . earthquake viscoelastic dampers are a classic example @xcite . |
3,155 | Suppose that you have an abstract for a scientific paper: a set @xmath0 of vertices of an acyclic digraph @xmath1 is convex if @xmath2 and there is no directed path between vertices of @xmath0 which contains a vertex not in @xmath0 .
a set @xmath0 is connected if @xmath2 and the underlying undirected graph of the subgraph of @xmath1 induced by @xmath0 is connected .
connected convex sets and convex sets of acyclic digraphs are of interest in the area of modern embedded processor technology .
we construct an algorithm @xmath3 for enumeration of all connected convex sets of an acyclic digraph @xmath1 of order @xmath4 .
the time complexity of @xmath3 is @xmath5 , where @xmath6 is the number of connected convex sets in @xmath1 .
we also give an optimal algorithm for enumeration of all ( not just connected ) convex sets of an acyclic digraph @xmath1 of order @xmath4 . in computational experiments
we demonstrate that our algorithms outperform the best algorithms in the literature . using the same approach as for @xmath3
, we design an algorithm for generating all connected sets of a connected undirected graph @xmath7 .
the complexity of the algorithm is @xmath8 where @xmath4 is the order of @xmath7 and @xmath9 is the number of connected sets of @xmath10 the previously reported algorithm for connected set enumeration is of running time @xmath11 , where @xmath12 is the number of edges in @xmath10 .
And you have already written the first three sentences of the full article: a set @xmath0 of vertices of an acyclic digraph @xmath1 is _ convex _ if @xmath13 and there is no directed path between vertices of @xmath0 which contains a vertex not in @xmath0 .
a set @xmath0 is _ connected _ if @xmath13 and the underlying undirected graph of the subgraph of @xmath1 induced by @xmath0 is connected .
a set is _ connected convex _ ( a _ cc - set _ ) if it is both connected and convex . in section [ ccsec ] , we introduce and study an algorithm @xmath3 for generating all connected convex sets of a connected acyclic digraph @xmath1 of order @xmath4 ..
Please generate the next two sentences of the article | the running time of @xmath3 is @xmath5 , where @xmath6 is the number of connected convex sets in @xmath1 .
thus , the algorithm is ( almost ) optimal with respect to its time complexity . |
3,156 | Suppose that you have an abstract for a scientific paper: we present a _ revised iras - fsc redshift catalogue _ ( rifscz ) of 60,303 galaxies selected at 60 @xmath0 from the _ iras faint source catalogue _ ( fsc ) .
this revision merges in data from the wise all - sky data release , the tenth sdss data release ( dr10 ) , the galex all - sky survey source catalog ( gasc ) , the 2mass redshift survey ( 2mrs ) and the planck catalogue of compact sources ( pccs ) .
the rifscz consists of accurate position , ultra - violet ( uv ) , optical , near- , mid- and far - infrared , sub - millimetre ( sub - mm ) and/or radio identifications , spectroscopic redshift ( if available ) or photometric redshift ( if possible ) , predicted far - infrared and sub - mm fluxes ranging from 12 to 1380 @xmath0 based upon the best - fit infrared template .
we also provide stellar masses , star - formation rates and dust masses derived from the optical and infrared template fits , where possible .
@xmath1 of the galaxies in the rifscz have spectroscopic redshifts and a further @xmath2 have photometric redshifts obtained through the template - fitting method . at s60 @xmath3 0.36 jy , the 90@xmath4 completeness limit of the fsc ,
@xmath5 of the sources in the rifscz have either spectroscopic or photometric redshifts .
an interesting subset of the catalogue is the sources detected by planck at sub - mm wavelengths .
1200 sources have a detection at better than 5-@xmath6 in at least one planck band and a further 1186 sources have detections at 3 - 5@xmath6 in at least one planck band . catalogues
surveys galaxies : distances and redshifts infrared : galaxies quasars : general large - scale structure of universe . .
And you have already written the first three sentences of the full article: the _ iras faint source catalog _ ( fsc ; moshir et al .
1992 ) contains 173,044 sources reaching a depth of @xmath70.2 jy at 12 , 25 and 60 @xmath0 .
it is limited to @xmath8 in unconfused regions at 60 @xmath0 . for sources with high - quality flux density ,.
Please generate the next two sentences of the article | reliability is @xmath9 at 12 and 25 @xmath0 and @xmath10 at 60 @xmath0 . around 41@xmath4 of the fsc sources
are detected at 60 @xmath11 m ( fqual @xmath3 1 ) . |
3,157 | Suppose that you have an abstract for a scientific paper: the exact frame - dragging ( or lense - thirring ( lt ) precession ) rates for kerr , kerr - taub - nut ( ktn ) and taub - nut spacetimes have been derived .
remarkably , in the case of the ` zero angular momentum ' taub - nut spacetime , the frame - dragging effect is shown not to vanish , when considered for spinning test gyroscope . in the case of the interior of the pulsars , the exact frame - dragging rate monotonically decreases from the center to the surface along the pole and but it shows an ` anomaly ' along the equator . moving from the equator to the pole
, it is observed that this ` anomaly ' disappears after crossing a critical angle .
the ` same ' anomaly can also be found in the ktn spacetime .
the resemblance of the anomalous lt precessions in the ktn spacetimes and the spacetime of the pulsars could be used to identify a role of taub - nut solutions in the astrophysical observations or equivalently , a signature of the existence of nut charge in the pulsars . .
And you have already written the first three sentences of the full article: stationary spacetimes with angular momentum ( rotation ) are known to exhibit an effect called lense - thirring ( lt ) precession whereby locally inertial frames are dragged along the rotating spacetime , making any test gyroscope in such spacetimes _ precess _ with a certain frequency called the lt precession frequency @xcite .
this frequency has been shown to decay as the inverse cube of the distance of the test gyroscope from the source for large enough distances where curvature effects are small , and known to be proportional to the angular momentum of the source .
the largest precession frequencies are thus expected to be seen very close to the source ( like the surface of a pulsar , or the horizon of a black hole ) , as well as for spacetimes rotating very fast with large angular momenta ..
Please generate the next two sentences of the article | earlier analyses of the lt effect @xcite assume slowly rotating ( @xmath0 is the kerr parameter of the rotating spacetime due to a compact object like a black hole ) spacetime for the test gyroscope @xcite . thus , the rotating spacetime solution is usually approximated as a schwarzschild spacetime , and the effect of rotation is confined to a perturbative term added on to the schwarzschild metric .
this leads to the standard result for lt precession frequency in the weak field approximation , given by @xcite @xmath1 \label{we1}\ ] ] where , @xmath2 is the unit vector along @xmath3 direction . in a recent work reported in ref . |
3,158 | Suppose that you have an abstract for a scientific paper: in this report we show that in a planar exponentially growing network consisting of @xmath0 nodes , congestion scales as @xmath1 independently of how flows may be routed .
this is in contrast to the @xmath2 scaling of congestion in a flat polynomially growing network .
we also show that without the planarity condition , congestion in a small world network could scale as low as @xmath3 , for arbitrarily small @xmath4 .
these extreme results demonstrate that the small world property by itself can not provide guidance on the level of congestion in a network and other characteristics are needed for better resolution . finally , we investigate scaling of congestion under the geodesic flow , that is , when flows are routed on shortest paths based on a link metric . here
we prove that if the link weights are scaled by arbitrarily small or large multipliers then considerable changes in congestion may occur .
however , if we constrain the link - weight multipliers to be bounded away from both zero and infinity , then variations in congestion due to such remetrization are negligible . .
And you have already written the first three sentences of the full article: the study of large - scale ( complex ) networks , such as computer , biological and social networks , is a multidisciplinary field that combines ideas from mathematics , physics , biology , social sciences and other fields .
a remarkable and widely discussed phenomena associated with such networks is the _ small world _ property .
it is observed in many such networks , man - made or natural , that the typical distance between the nodes is surprisingly small ..
Please generate the next two sentences of the article | more formally , as a function of the number of nodes , @xmath0 , the average distance between a node pair typically scales at or below @xmath5 . in this work ,
we study the load characteristics of small world networks . |
3,159 | Suppose that you have an abstract for a scientific paper: high - resolution mid - infrared images have been obtained in n - band and q - band for the proto - planetary nebula iras 16594@xmath04656 .
a bright equatorial torus and a pair of bipolar lobes can clearly be seen in the infrared images .
the torus appears thinner at the center than at the edges , suggesting that it is viewed nearly edge - on .
the infrared lobes correspond to the brightest lobes of the reflection nebula seen in the hubble space telescope ( _ hst _ ) optical image , but with no sign of the point - symmetric structure seen in the visible image .
the lobe structure shows a close correspondence with a molecular hydrogen map obtained with _
hst _ , suggesting that the dust emission in the lobes traces the distribution of the shocked gas .
the shape of the bipolar lobes shows clearly that the fast outflow is still confined by the remnant circumstellar envelope of the progenitor asymptotic giant branch ( agb ) star .
however , the non - detection of the dust outside of the lobes suggests that the temperature of the dust in the agb envelope is too low for it to be detected at 20 @xmath1 m . .
And you have already written the first three sentences of the full article: proto - planetary nebulae ( ppne ) are the long - sought - after missing link between the end of the asymptotic giant branch ( agb ) phase and the beginning of planetary nebula phase of stellar evolution . after the _ infrared astronomical satellite _ ( _ iras _ ) mission , a number of objects were proposed as candidate ppne based on their infrared colors and other spectral properties .
these are typically stars of g to b spectral type with significant infrared excesses due to the remnant circumstellar dust shell ejected in the agb phase .
of particular interest among these candidates are a number of carbon - rich objects whose abundances show a strong enhancement of s - process elements , as expected from the dredge - up of material in thermal pulses during the agb evolution @xcite . for other candidates there is some possibility of confusion with massive supergiants , but those in this carbon - rich group are almost certainly bona - fide ppne ..
Please generate the next two sentences of the article | one of these objects is iras 16594@xmath04656 .
it is a bright mid - infrared source which has typical colors of a ppn @xcite . |
3,160 | Suppose that you have an abstract for a scientific paper: longitudinal space charge ( lsc ) effects are generally considered as harmful in free - electron lasers as they can seed unfavorable energy modulations that can result in density modulations with associated emittance dilution .
this `` micro - bunching instabilities '' is naturally broadband and could possibly support the generation of coherent radiation over a broad region of the spectrum . therefore there has been an increasing interest in devising accelerator beam lines capable of controlling lsc induced density modulations . in the present paper
we refine these previous investigations by combining a grid - less space charge algorithm with the popular particle - tracking program elegant .
this high - fidelity model of the space charge is used to benchmark conventional lsc models .
we finally employ the developed model to investigate the performance of a cascaded lsc amplifier using beam parameters comparable to the ones achievable at fermilab accelerator science & technology ( fast ) facility currently under commissioning at fermilab .
linear accelerator , electron beams , space charge , micro - bunching instabilities , @xmath0-body tree algorithm .
And you have already written the first three sentences of the full article: longitudinal - space - charge - driven micro - bunching instabilities arising in bunch compressors were predicted and observed over the last decade @xcite . it was recently proposed to employ such micro - bunching instability mechanism to form attosecond structures on the bunch current distribution for the subsequent generation of coherent radiation pulses @xcite .
a possible beam line configuration capable of enabling the micro - bunching instability is relatively simple .
it essentially consists of focusing section ( e.g. fodo cells ) where energy modulations due to the lsc impedance accumulate , followed by a longitudinally - dispersive section ..
Please generate the next two sentences of the article | the latter section , by introducing an energy dependent path length , converts the incoming energy modulation into a density modulation .
such an elementary cell is often referred to as a lsc amplifier ( lsca ) . |
3,161 | Suppose that you have an abstract for a scientific paper: in this paper , we prove the existence of doubly connected v - states for the generalized sqg equations with @xmath00,1[.$ ] they can be described by countable branches bifurcating from the annulus at some explicit `` eigenvalues '' related to bessel functions of the first kind .
contrary to euler equations @xcite , we find v - states rotating with positive and negative angular velocities . at the end of the paper
we discuss some numerical experiments concerning the limiting v - states . .
And you have already written the first three sentences of the full article: the present work deals with the generalized surface quasi - geostrophic equation ( gsqg ) arising in fluid dynamics and which describes the evolution of the potential temperature @xmath1 by the transport equation : @xmath2 here @xmath3 refers to the velocity field , @xmath4 and @xmath5 is a real parameter taken in @xmath60,2[$ ] .
the singular operator @xmath7 is of convolution type and defined by , @xmath8 with @xmath9 where @xmath10 stands for the gamma function .
this model was proposed by crdoba et al . in @xcite as an interpolation between euler equations and the surface quasi - geostrophic model ( sqg ) corresponding to @xmath11 and @xmath12 , respectively ..
Please generate the next two sentences of the article | the sqg equation was used by juckes @xcite and held et al .
@xcite to describe the atmosphere circulation near the tropopause . |
3,162 | Suppose that you have an abstract for a scientific paper: we present the results of a search for the ground state hyperfine transition of the oh radical near 53 mhz using the national mst radar facility at gadanki , india .
the observed position was [email protected] near the galactic plane .
the oh line is not detected .
we place a 3@xmath1 upper limit for the line flux density at 39 jy from our observations .
we also did not detect recombination lines ( rls ) of carbon , which were within the frequency range of our observations .
the 3@xmath1 upper limit of 20 jy obtained for the flux density of carbon rl , along with observations at 34.5 and 327 mhz are used to constrain the physical properties of the line forming region .
our upper limit is consistent with the line emission expected from a partially ionized region with electron temperature , density and path lengths in the range 20 300 k , 0.03 0.3 @xmath2 and 0.1 170 pc respectively ( kantharia & anantharamaiah 2001 ) .
[ firstpage ] ism : general ism : lines and bands
ism : molecules radio lines : ism radio lines : general galaxy : general . .
And you have already written the first three sentences of the full article: a large variety of molecules , including complex organic ones , have been detected in the galactic interstellar medium .
the hydroxyl ( oh ) radical is quite abundant in the galactic plane and has several rotational transitions that are easily observed at microwave frequencies .
these lines are found to originate from thermal processes as well as non - thermal processes ( i.e. maser emission ) ..
Please generate the next two sentences of the article | thermal emission from oh radical was first detected in 1963 ( weinreb et al . 1963 ) .
the thermal lines are observed from extended regions in the galactic plane . on the other hand , maser emission from oh radical |
3,163 | Suppose that you have an abstract for a scientific paper: the charge collection properties of cvd diamond have been investigated with ionising radiation . in this study two cvd diamond samples , prepared with electrical contacts have been used as solid state ionisation chambers .
the diamonds have been studied with beta particles and 10 kev photons , providing a homogeneous ionisation density and with protons and alpha particles which are absorbed in a thin surface layer . for the latter case a strong decrease of the signal as function of time is observed , which is attributed to polarisation effects inside the diamond .
spatially resolved measurements with protons show a large variation of the charge collection efficiency , whereas for photons and minimum ionising particles the response is much more uniform and in the order of 18% .
these results indicate that the applicability of cvd diamond as a position sensitive particle detector depends on the ionisation type and appears to be promising for homogeneous ionisation densities as provided by relativistic charged particles .
epsf ps .
ps , , , , and cvd diamond , charge collection efficiency . 29.40 .
And you have already written the first three sentences of the full article: in recent years , diamond as a possible material for particle detectors has been the subject of considerable interest @xcite .
significant progress in the techniques to produce synthetical diamond films of very high quality has been achieved by means of the chemical vapour deposition method ( cvd ) .
a number of commercial manufactures of cvd diamond films @xcite and research institutes @xcite have made systematic studies of the properties of this material feasible ..
Please generate the next two sentences of the article | the main advantage of the material compared to other semiconductor detector materials is its radiation hardness , which has recently been demonstrated to neutron fluences of up to @xmath0@xcite .
the radiation hardness of the material is of strong interest for the detector development at projected experiments where high radiation levels are expected due to the increasing luminosity and energy , as e.g. the experiments at the large hadron collider at cern . |
3,164 | Suppose that you have an abstract for a scientific paper: using exact enumeration methods and monte carlo simulations we study the phase diagram relative to the conformational transitions of a two dimensional diblock copolymer .
the polymer is made of two homogeneous strands of monomers of different species which are joined to each other at one end .
we find that depending on the values of the energy parameters in the model , there is either a first order collapse from a swollen to a compact phase of spiral type , or a continuous transition to an intermediate zipped phase followed by a first order collapse at lower temperatures .
critical exponents of the zipping transition are computed and their exact values are conjectured on the basis of a mapping onto percolation geometry , thanks to recent results on path - crossing probabilities . 2 .
And you have already written the first three sentences of the full article: polymers in solution typically undergo a coil - globule transition from a high temperature ( t ) swollen phase to a low t phase where the polymer assumes compact conformations . in the case of homopolymers , for which all the monomers are identical , this transition is by now well understood
it is known as @xmath0-collapse and has been widely investigated in the past years using various methods such as mean field approximations @xcite , exact enumerations of interacting self - avoiding walks on lattices @xcite , monte carlo @xcite , transfer matrix @xcite and field theoretical calculations @xcite . in two dimensions
the exponents of the @xmath0-collapse have been related to the fractal properties of the percolation cluster and are believed to be known exactly @xcite ..
Please generate the next two sentences of the article | the study of the conformational properties and phase transitions of macromolecules with inhomogeneous or random sequences of monomers is an interesting frontier in nowadays polymer statistics @xcite .
these systems pose new theoretical and numerical challenges , compared to their more standard , homogeneous counterparts . |
3,165 | Suppose that you have an abstract for a scientific paper: we investigate the entrainment of a neuron model exhibiting a chaotic spiking - bursting behavior in response to a weak periodic force .
this model exhibits two types of oscillations with different characteristic time scales , namely , long and short time scales .
several types of phase synchronization are observed , such as @xmath0 phase locking between a single spike and one period of the force and @xmath1 phase locking between the period of slow oscillation underlying bursts and @xmath2 periods of the force .
moreover , spiking - bursting oscillations with chaotic firing patterns can be synchronized with the periodic force .
such a type of phase synchronization is detected from the position of a set of points on a unit circle , which is determined by the phase of the periodic force at each spiking time .
we show that this detection method is effective for a system with multiple time scales .
owing to the existence of both the short and the long time scales , two characteristic phenomena are found around the transition point to chaotic phase synchronization .
one phenomenon shows that the average time interval between successive phase slips exhibits a power - law scaling against the driving force strength and that the scaling exponent has an unsmooth dependence on the changes in the driving force strength .
the other phenomenon shows that kuramoto s order parameter before the transition exhibits stepwise behavior as a function of the driving force strength , contrary to the smooth transition in a model with a single time scale . .
And you have already written the first three sentences of the full article: since the discovery of synchronization in pendulum clocks by huygens , synchronous behavior has been widely observed not only in physical systems but also in biological ones such as pacemaker cells in the heart , chirps of crickets , and fetal - maternal heart rate synchronization @xcite .
such synchronization phenomena have been studied theoretically in terms of nonlinear dynamics , particularly by exploiting oscillator models @xcite . for example , synchronization observed in fireflies can be modeled using nonlinear periodic oscillators and is described as _
phase synchronization_. further , it has been indicated that the notion of phase synchronization can be extended to chaotic oscillators ..
Please generate the next two sentences of the article | this phenomenon is called _ chaotic phase synchronization _ ( cps ) @xcite .
furthermore , synchronization phenomena in neural systems have also attracted considerable attention in recent years . at the macroscopic level of the brain activity |
3,166 | Suppose that you have an abstract for a scientific paper: we investigate the effects of the light vector u - boson that couples weakly to nucleons in relativistic mean - field models on the equation of state and subsequently the consequence in neutron stars .
it is analyzed that the u - boson can lead to a much clearer rise of the neutron star maximum mass in models with the much softer equation of state .
the inclusion of the u - boson may thus allow the existence of the non - nucleonic degrees of freedom in the interior of large mass neutron stars initiated with the favorably soft eos of normal nuclear matter .
in addition , the sensitive role of the u - boson in the neutron star radius and its relation to the test of the non - newtonian gravity that is herein addressed by the light u - boson are discussed . .
And you have already written the first three sentences of the full article: confronting nuclear physics , we should highlight the great importance of the equation of state ( eos ) , for it being significantly important to study the structure of nuclei , the reaction dynamics of heavy - ion collisions , and many issues in astrophysics @xcite .
the nuclear eos consists usually of two ingredients : the energy density for symmetric matter and the density dependence of the symmetry energy . for the former ,
the saturation properties are quite clear nowadays , though its high - density behavior remains to be revealed in more details ..
Please generate the next two sentences of the article | however , the density dependence of the symmetry energy is still poorly known especially at high densities @xcite , and even the trend of the density dependence of the symmetry energy can be predicted to be contrary . while most relativistic theories @xcite and some non - relativistic theories @xcite predict that the symmetry energy increases continuously at all densities , many other non - relativistic theories ( for instance , see @xcite ) , in contrast , predict that the symmetry energy first increases , then decreases above certain supra - saturation densities , and even in some predictions @xcite becomes negative at high densities , referred as the super - soft symmetry energy .
therefore , the experimental extraction is of necessity . |
3,167 | Suppose that you have an abstract for a scientific paper: we have constructed the lowest few eigenvectors of the staggered dirac operator on @xmath0 gauge configurations , both quenched and dynamical .
we use these modes to study the topological charge and to construct approximate hadronic correlators . .
And you have already written the first three sentences of the full article: in a recent study @xcite we successfully calculated the mass of the @xmath1 meson using staggered fermions . according to conventional lore
, the @xmath1 receives a large portion of its mass from instanton effects . at the fermionic level
, this would mean receiving contributions from zero modes of the dirac operator ..
Please generate the next two sentences of the article | these zero modes come with a definite chirality in the continuum and are associated with the topological charge ( @xmath2 ) of a gauge configuration via the index theorem : @xmath3 where @xmath4 and @xmath5 are respectively the number of right and left - handed zero modes . at finite lattice spacing ,
@xmath6 and @xmath7 do not exactly anti - commute , so there are no exact chiral zero modes and nor is the topological charge of gauge configurations well defined . |
3,168 | Suppose that you have an abstract for a scientific paper: we extend our modeling of cooling of superfluid neutron stars by including the production of muons in the core , in addition to neutrons , protons , and electrons .
the results are confronted with observations of middle - aged isolated nss .
muons have little effect on the hydrostatic structure of nss , on the slow cooling of low - mass nss ( rx j082243 and psr 105552 in our model ) and on the rapid cooling of massive nss .
they affect , however , the moderately fast cooling of medium - mass nss ( 1e 120752 , rx j0002 + 62 , psr 0656 + 14 , vela , and geminga ) and shift appreciably the mass range of these nss to lower masses , which is important for correct interpretation of the observations . moreover , the effects of muons can accurately be reproduced by a simple renormalization of ns models with no muons in the ns cores . .
And you have already written the first three sentences of the full article: rapid progress in detecting thermal emission from isolated neutron stars ( nss ) with a new generation of orbital and ground - based observatories ( e.g. , refs .
@xcite ) stimulates active theoretical studies of cooling isolated nss .
it is well known that cooling history of nss depends on physical properties of matter of supranuclear density in ns cores ..
Please generate the next two sentences of the article | these properties ( composition of matter , equation of state eos , critical temperatures of various superfluids , etc . )
are largely unknown : they can not be reproduced in laboratory or unambiguously calculated ( because of the lack of exact manybody theory for describing the systems of particles interacting via strong forces ) . |
3,169 | Suppose that you have an abstract for a scientific paper: the gemini deep deep survey , gdds , produced several significant results relating to the evolution of galaxies .
all of these results are consistent with the downsizing " concept of galaxy formation and evolution , i.e. , that the active periods of star formation moved progressively from very massive galaxies at high redshift to much lower mass galaxies at the present epoch .
spectra of massive red galaxies at z @xmath0 1.7 demonstrates that they contain old stellar populations and hence must have formed their stars in the first @xmath1gyr of cosmic history ; indicators of star formation activity show that the star formation rate in the most massive galaxies was much higher at @xmath2 than today , that the activity in intermediate mass galaxies peaked near @xmath3 , while , since @xmath4 the activity is primarily confined to lower mass galaxies .
the gdds also uncovered a relatively high percentage of post - starburst galaxies at @xmath4 , a result that is anticipated given all the activity seen at higher redshifts .
measurements of the strengths of metal lines of a subsample of the gdds and cfrs galaxies at @xmath5 reveal that , at a given mass , they had lower metallicities than at present .
the evolution in the mass - metallicity relation is consistent with a model in which star formation lasts longest in less massive galaxies , again an expected result in the downsizing scenario . .
And you have already written the first three sentences of the full article: the formation and evolution of galaxies has been one of the primary topics in cosmology ever since their diverse appearance was first observed .
naive interpretations of the hubble sequence of galaxies and of the hierarchical nature of dark matter halos in cdm models naturally lead to scenarios in which smaller galaxies , predominantly spirals , form first and then merge to form the massive spheroidal systems .
the variation of the star formation rate density as a function of redshift ( lilly et al ..
Please generate the next two sentences of the article | 1996 , madau et al.1996 ) shows that almost half of the stellar mass in galaxies was formed between @xmath6 so that it is obviously vital to study this epoch to understand galaxy evolution .
the gdds survey ( abraham et al . 2004 ) , through preselection criteria applied to a deep infrared survey of galaxies , was specifically designed for this purpose . |
3,170 | Suppose that you have an abstract for a scientific paper: the charmed @xmath0 decays , @xmath1 and @xmath2 , are re - analyzed using the latest experimental data , where @xmath3 and @xmath4 denote the pseudoscalar meson and vector meson , respectively .
we perform global fits under the assumption of flavor su(3 ) symmetry .
the size of the decay amplitudes and the strong phases between the topologically distinct amplitudes are studied .
predictions of the related @xmath5 decay rates are made based upon the fitted results .
we also note a serious su(3 ) symmetry breaking or inconsistency in the @xmath2 sector .
-1 cm .
And you have already written the first three sentences of the full article: the hadronic decays of @xmath0 mesons have provided us with a good place to study cp violation in particle physics . in particular
, the detection of direct cp violation in a decay process requires that there exist at least two contributing amplitudes with different weak and strong phases .
the direct cp - violating effect in the @xmath0 system has finally been observed in the @xmath6 decay at the @xmath0-factories @xcite , proving the existence of nontrivial strong phases in @xmath0 decays ..
Please generate the next two sentences of the article | it is therefore of consequence to find out the patterns of final - state strong phases for a wider set of decay modes . since the ckm factors involved in charmed @xmath0 meson decays are purely real to a good approximation , the phases associated with the decay amplitudes thus have the origin of strong interactions .
such final - state rescattering effects have been noticed from data in these decays @xcite , and estimated to be at 15 - 20% level @xcite . |
3,171 | Suppose that you have an abstract for a scientific paper: let @xmath0 be a real hyperplane arrangement which is stable under the action of a coxeter group @xmath1 .
then @xmath1 acts naturally on the set of chambers of @xmath0 .
we assume that @xmath0 is disjoint from the coxeter arrangement @xmath2 of @xmath1 . in this paper , we show that the @xmath1-orbits of the set of chambers of @xmath3 are in one - to - one correspondence with the chambers of @xmath4 which are contained in an arbitrarily fixed chamber of @xmath5 .
from this fact , we find that the number of @xmath1-orbits of the set of chambers of @xmath0 is given by the number of chambers of @xmath6 divided by the order of @xmath1
. we will also study the set of chambers of @xmath6 which are contained in a chamber @xmath7 of @xmath0 .
we prove that the cardinality of this set is equal to the order of the isotropy subgroup @xmath8 of @xmath7 .
we illustrate these results with some examples , and solve an open problem in [ h. kamiya , a. takemura , h. terao , ranking patterns of unfolding models of codimension one , adv . in appl .
math .
47 ( 2011 ) 379400 ] by using our results .
_ keywords : _ all - subset arrangement , braid arrangement , catalan arrangement , characteristic polynomial , coxeter arrangement , coxeter group , finite - field method , mid - hyperplane arrangement , semiorder , symmetric group .
_ msc2010 : _ 20f55 , 32s22 , 52c35 . .
And you have already written the first three sentences of the full article: let @xmath0 be a real hyperplane arrangement which is stable under the action of a coxeter group @xmath1 .
then @xmath1 acts naturally on the set @xmath9 of chambers of @xmath0 .
we want to find the number of @xmath1-orbits of @xmath9 ..
Please generate the next two sentences of the article | a particular case of this problem was considered in the authors previous paper ( kamiya , takemura and terao @xcite ) and the present paper is motivated by an open problem left in section 6 of @xcite . by the general results of the present paper , we give the affirmative answer to the open problem in theorem [ thm : affirmative ] .
suppose throughout that @xmath10 , where @xmath2 is the coxeter arrangement of @xmath1 . in this paper |
3,172 | Suppose that you have an abstract for a scientific paper: in our previous paper @xcite we presented the design and initial calibrations of the dual - beam imaging polarimeter ( dbip ) , a new optical instrument for the university of hawaii s @xmath0 m telescope on the summit of mauna kea , hawaii . in this followup work
we discuss our full - stokes mode commissioning including crosstalk determination and our typical observing methodology . .
And you have already written the first three sentences of the full article: to study the linear polarization of asteroids and other point source objects , the dual - beam imaging polarimeter ( dbip ) was commissioned in march of 2007 @xcite . in august of 2007 we expanded dbip s capabilities to include analysis of circular polarization with the addition of a quarterwave plate . typically , the most important quantities for analysis are the fractional polarizations @xmath1 , @xmath2 , and @xmath3 , expressed as percentages , and in the following text we will deal with these quantities when we refer to polarization measurements . here
we present our subsequent calibration and determination of systematic errors which were found to be comparable to statistical errors for typical observing situations : @xmath4 polarization .
the original setup of dbip was a serial arrangement of a halfwave plate in an encoded rotation stage , a filter and a double - calcite savart plate placed between the telescope and the @xmath5 tektronix ccd camera . to extend dbip to full - stokes sensitivity , a quarterwave plate in a rotation stage.
Please generate the next two sentences of the article | was placed ahead of the halfwave plate .
this setup allows for simultaneous measurement of linear and circular polarization , though at the potential cost of increased crosstalk between polarizations , which is discussed further in [ jrm_crosstalk ] figure [ jrm_fig.optics ] , modified from @xcite , shows a schematic representation of the new optical path with the quarterwave plate added . |
3,173 | Suppose that you have an abstract for a scientific paper: in this paper we have constructed a new class of thin - shell wormholes from black holes in hoava - lifshitz gravity .
particular emphasis is placed on those aspects that allow a comparison of hoava - lifshitz to einstein gravity .
the former enjoys a number of advantages for small values of the throat radius .
pac numbers : 04.40.nr , 04.20.jb , 04.20.dw .
And you have already written the first three sentences of the full article: a new renormalizable gravity theory in four dimensions , proposed by hoava @xcite , may be regarded as a uv complete candidate for general relativity . at large distances
the theory reduces to einstein gravity with a non - vanishing cosmological constant in ir , but with improved uv behavior . as discussed in ref .
@xcite , from the ir - modified hoava action , which reduces to the standard einstein - hilbert action in the ir limit , one obtains the analogue of the standard spherically symmetric schwarzschild-(a)ds black - hole solution ..
Please generate the next two sentences of the article | in this paper we employ such a class of black holes by starting with two copies thereof and constructing a traversable thin - shell wormhole by means of the cut - and - paste technique @xcite . to compare and contrast the two gravitational theories , we discuss various aspects of these wormholes , such as the location of the event horizons , the energy density of the thin shell , the violation of the weak energy condition at the junction surface , the amount of exotic matter required , and the equation of state . our final topic is the question of stability to a linearized spherically symmetric perturbation .
consider the static and spherically symmetric line element @xmath0 the modified hoava action mentioned above is @xmath1,\end{gathered}\ ] ] where @xmath2@xcite . here |
3,174 | Suppose that you have an abstract for a scientific paper: bimno@xmath0 ( bmo ) , ferromagnetic ( fm ) below @xmath1 100 k , was believed to be also ferroelectric ( fe ) due to a non - centro - symmetric c2 structure , until diffraction data indicated that its space group is the centro - symmetric c2/c . here
we present infrared phonon spectra of bmo , taken on a mosaic of single crystals , which are consistent with c2/c at any @xmath2 10 k , as well as room - temperature raman data which strongly support this conclusion .
we also find that the infrared intensity of several phonons increases steadily for @xmath3 , causing the relative permittivity of bmo to vary from 18.5 at 300 k to 45 at 10 k. at variance with fe materials of displacive type , no appreciable softening has been found in the infrared phonons .
both their frequencies and intensities , moreover , appear insensitive to the fm transition at @xmath4 . .
And you have already written the first three sentences of the full article: the possible multiferroicity - or , more precisely , magnetoelectricity - of bimno@xmath0 ( bmo ) , namely the simultaneous occurrence of ferroelectric ( fe ) and ferromagnetic ( fm ) long - range order in this simple perovskite , has been long discussed in the literature @xcite .
such interest is justified by its potential applications , which may span from giant electric transformers and multiple - state memory elements , to spintronics , magnetoelectric sensors , electric - field controlled ferromagnetic devices , and variable transducers @xcite
. indeed , on one hand bimno@xmath0 is ferromagnetic below @xcite @xmath1 100 k , due to superexchange along the mn@xmath5-o@xmath6mn@xmath5 chains , with a maximum reported magnetization of 3.92 @xmath7 per formula unit @xcite ..
Please generate the next two sentences of the article | on the other hand , the bi@xmath5 ( 6s@xmath8 ) lone pair could experience a repulsion from the 2p orbitals of neighboring oxygen ions , leading to a permanent electric dipole and a ferroelectric distortion of the perovskite unit cell .
however , both the detection of ferroelectricity , and the observation of such distortion have been long controversial , also for the difficulty to grow single crystals @xcite of bmo , being it metastable at ambient pressure @xcite . |
3,175 | Suppose that you have an abstract for a scientific paper: we present a new method to estimate three - point correlations in cosmic microwave background maps .
our fast fourier transform based implementation estimates three - point functions using all possible configurations ( triangles ) at a controlled resolution .
the speed of the technique depends both on the resolution and the total number of pixels @xmath0 .
the resulting @xmath1 scaling is substantially faster than naive methods with prohibitive @xmath2 scaling . as an initial application ,
we measure three - point correlation functions in the first year data release of the wilkinson anisotropy probe .
we estimate 336 cross - correlations of any triplet of maps from the 8 differential assemblies , scanning altogether 2.6 million triangular configurations .
estimating covariances from gaussian signal plus realistic noise simulations , we perform a null - hypothesis testing with regards to the gaussianity of the cosmic microwave background .
our main result is that at the three - point level wmap is fully consistent with gaussianity . to quantify the level of possible deviations , we introduce false discovery rate analysis , a novel statistical technique to analyze for three - point measurements
this confirms that the data are consistent with gaussianity at better than 1-@xmath3 level when jointly considering all configurations .
we constrain a specific non - gaussian model using the quadratic approximation of weak non - gaussianities in terms of the @xmath4 parameter , for which we construct an estimator from the the three - point function .
we find that using the skewness alone is more constraining than a heuristic suboptimal combination of all our results ; our best estimate is @xmath5 assuming a @xmath6cdm concordance model . .
And you have already written the first three sentences of the full article: the temperature fluctuations in the cosmic microwave background ( cmb ) are gaussian to a high degree of accuracy @xcite .
non - gaussianity , if any , enters at a highly subdominant level
. it could be either primordially generated along with gaussian fluctuations by exotic inflationary models , and/or it could arise from secondary anisotropies , such as gravitational lensing , sunyaev - zeldovich ( sz ) , or sachs - wolfe ( sw ) effects . quantifying the degree and nature of non - gaussianity in the cmb.
Please generate the next two sentences of the article | constrains specific inflationary models , as well as enhances our understanding of the secondary processes the cmb underwent beyond the surface of last scattering .
interpretation of any such measurement is complicated by the fact that systematics and foreground contaminations might also produce non - gaussian signatures . |
3,176 | Suppose that you have an abstract for a scientific paper: the motion of satellite galaxies around normal galaxies at distances 50 - 500 kpc provides a sensitive test for the theories .
we study the surface density and the velocities of satellites around isolated red galaxies in the sloan digital sky survey .
we find that the surface number - density of satellites declines with the projected distance as a power law with the slope @xmath0 .
the rms velocities gradually decline : observations exclude constant velocities at a @xmath1 level .
we show that observational data strongly favor the standard model : all three major statistics of satellites the number - density profile , the line - of - sight velocity dispersion , and the distribution function of the velocities agree remarkably well with the predictions of the standard cosmological model .
thus , that the success of the standard model extends to scales ( 50 - 500 ) kpc , much lower than what was previously considered .
mond fails on these scales for models which assume any single power - law number - density profile of satellites and any constant velocity anisotropy by predicting nearly constant rms velocities of satellites .
satellite data can be fit by fine - tuned models , which require ( 1 ) specific non - power - law density profile , ( 2 ) very radial orbits at large distances ( velocity anisotropy @xmath2 at @xmath3 kpc ) , and ( 3 ) 2 - 2.5 times more stellar mass than what is found in the galaxies .
the external gravity force a necessary component for mond makes the situation even worse .
we argue that a combination of satellite data and observational constraints on stellar masses make these models very problematic . #
1to 0pt#1 .
And you have already written the first three sentences of the full article: one hundred years after einstein , the theory of general relativity ( gr ) is still our best theory of gravity . in the framework of gr
, the standard model of cosmology ( @xmath4 ) provides a successful description of the universe . in this model , the same fluctuations which give rise to the observed small variations in the temperature of the cosmic microwave background ( cmb )
grow under the force of gravity , and eventually form observed galaxies and other nonlinear structures such as filaments , voids , groups and clusters of galaxies . according to the model , only @xmath5 of the density in the universe is provided by normal baryonic matter @xcite ..
Please generate the next two sentences of the article | the @xmath4 model requires two additional components : a non - baryonic cold dark matter ( cdm ) , which contributes about 30% of the average density of the universe , and an even more mysterious dark energy , which makes up the rest @xcite .
the model is remarkably successful on scales larger than a few megaparsecs . |
3,177 | Suppose that you have an abstract for a scientific paper: we discuss the link between dark matter halos hosting the first popiii stars formed at redshift @xmath0 and the rare , massive , halos that are generally considered to host bright @xmath1 quasars .
we show that within the typical volume occupied by one bright high - z qso the remnants of the first several thousands popiii stars formed do not end up in the most massive halos at @xmath1 , but rather live in a large variety of environments . the black hole seeds planted by these very first popiii stars
can easily grow to @xmath2 by @xmath3 assuming eddington accretion with radiative efficiency @xmath4 .
therefore quenching of the accretion is crucial to avoid an overabundance of supermassive black holes .
we implement a simple feedback model for the growth of the seeds planted by popiii stars and obtain a @xmath1 bh mass function consistent with the observed qso luminosity function .
address = space telescope science institute , 3700 san martin drive baltimore md 21218 usa address = space telescope science institute , 3700 san martin drive baltimore md 21218 usa , altaddress = department of physics and astronomy , johns hopkins university , baltimore , md 21218 usa .
And you have already written the first three sentences of the full article: population iii stars formed in the early universe at redshift @xmath5 with a top - heavy initial mass function ( e.g. see @xcite ) are expected to leave at the end of their lives intermediate mass black remnants of the order of @xmath6 .
these seeds , formed within dark matter halos of mass @xmath7 , may be the starting points for accretion that will lead to supermassive black holes ( @xmath8 ) , which are considered to power the luminosity of qsos , observed in the sloan digital sky survey ( sdss ) at @xmath9 when the universe was less than one billion years old ( e.g. see @xcite ) .
these bright qsos are extremely rare objects ( one object per about 200 deg@xmath10 in sdss , see @xcite ) , so we expect on average one per 1gpc@xmath11 comoving . within this volume.
Please generate the next two sentences of the article | the qso may either be the descendant of the first intermediate mass black hole seed left from the _ first _ popiii star , which would therefore give the most time for mass accretion , or sit at the center of the most massive structure at @xmath1 .
of course these two alternatives are in principle mutually non - exclusive , as the remnants of the first popiii stars could end up in the most massive dark matter halos at @xmath12 . |
3,178 | Suppose that you have an abstract for a scientific paper: as we go from center toward the surface of a neutron star , the state of baryonic matter changes from the de - confined quark - gluon to a mixed phase of quark and hadronic matter , and a thin crust of hadronic matter . for the quark matter , within mit bag model , the total energy density of the system is the kinetic energy for non - interacting quarks plus a bag constant . in this article
first we have considered a density dependent bag constant obtained using the recent experimental results of cern sps on the formation of a quark - gluon plasma . for calculations of the hadron phase
, we use the lowest order constrained variational method .
the equation of state of mixed phase has been determined using gibbs conditions . finally , we have calculated the structure of a hot neutron star with quark core employing tov equation .
our results show that a density dependent bag constant leads to a higher mass and lower radius for the hot neutron star with respect to the case in which we use a fixed bag constant . .
And you have already written the first three sentences of the full article: neutron stars ( ns ) are among the densest of massive objects in the universe . a hot neutron star is born following the gravitational collapse of the core of a massive star just after the supernova explosion .
the interior temperature of a neutron star at its birth is of the order @xmath0 @xcite .
as we go from the surface to the center of a neutron star , at sufficiently high densities , the matter is expected to undergo a transition from hadronic matter where the quarks are confined inside the hadrons to a state of deconfined quarks , with up , down and strange quarks in the quark matter ..
Please generate the next two sentences of the article | other quarks have higher masses and do not appear in this state .
glendenning has shown that a proper construction of the hadron - quark phase transition inside the neutron stars implies the coexistence of nucleonic matter and quark matter over a finite range of pressure . |
3,179 | Suppose that you have an abstract for a scientific paper: inequality and its consequences are the subject of intense recent debate . using a simplified model of the economy , we address the relation between inequality and liquidity , the latter understood as the frequency of economic exchanges . assuming a pareto distribution of wealth for the agents , that is consistent with empirical findings
, we find an inverse relation between wealth inequality and overall liquidity .
we show that an increase in the inequality of wealth results in an even sharper concentration of the liquid financial resources .
this leads to a congestion of the flow of goods and the arrest of the economy when the pareto exponent reaches one . .
And you have already written the first three sentences of the full article: today s global economy is more interconnected and complex than ever , and seems out of any particular institution s control .
the diversity of markets and traded products , the complexity of their structure and regulation , make it a daunting challenge to understand behaviours , predict trends or prevent systemic crises . the neo - classical approach , that aimed at explaining global behaviour in terms of perfectly rational actors , has largely failed @xcite .
yet , persistent statistical regularities in empirical data suggest that a less ambitious goal of explaining economic phenomena as emergent statistical properties of a large interacting system may be possible , without requiring much from agents rationality ( see e.g. @xcite ) ..
Please generate the next two sentences of the article | one of the most robust empirical stylised fact , since the work of pareto , is the observation of a broad distribution of wealth which approximately follows a power law .
such a power law distribution of wealth does not require sophisticated assumptions on the rationality of players , but it can be reproduced by a plethora of simple models ( see e.g. @xcite ) , in which it emerges as a typical behaviour i.e. as the behaviour that the system exhibits with very high probability within quite generic settings . |
3,180 | Suppose that you have an abstract for a scientific paper: we develop the basic properties of the higher commutator for congruence modular varieties . .
And you have already written the first three sentences of the full article: in @xcite , jonathan smith introduced a general commutator theory for algebras belonging to congruence permutable varieties that generalized the commutator theory for groups . in @xcite , joachim hagemann and christian hermann
extend the domain of applicability of the commutator to congruence modular varieties .
these developments precipitated the discovery of new structure theorems for algebras in congruence modular varieties , see for instance @xcite and @xcite . in @xcite ,.
Please generate the next two sentences of the article | heinz peter gumm presents the commutator from a geometrical perspective by drawing an analogy between congruence classes and affine subspaces of a vector space . in @xcite , ralph freese and ralph mckenzie define the commutator by a term condition and prove its equivalence to the definition of hagemann and hermann .
emil kiss showed in @xcite that the binary commutator can also be defined by a two term condition in congruence modular varieties . |
3,181 | Suppose that you have an abstract for a scientific paper: the conjecture that the gzk puzzle might be related with nontrivial structure of the inelastic defect of total cross sections in scattering from nuclei has been suggested . *
the gzk puzzle and fundamental dynamics * + a. a. arkhipov + _ state research center
institute for high energy physics " + 142281 protvino , moscow region , russia _ + .
And you have already written the first three sentences of the full article: from the history of fundamental science everybody knows that cosmic rays physics as a part of astrophysics and particle physics especially based on accelerator studies have many common roots .
in particular , many discoveries early in particle physics have been done in the study of cosmic rays .
it is enough to remind that the researches in cosmic rays resulted in the discovery of such elementary particles as the positron @xmath0 in 1932 , the muon .
Please generate the next two sentences of the article | second charged lepton @xmath1 in 1937 , the charged and neutral pions @xmath2 , @xmath3 , the strange particles kaons @xmath4 , @xmath5 , @xmath6 and @xmath7-hyperon in 1947 , the antiproton , @xmath8 and @xmath9 in 1952 - 1955 . in the very beginning of the second half of xx century
a period of divergence between cosmic rays physics and particle physics , both in methodology and in the places of interest , has been started . |
3,182 | Suppose that you have an abstract for a scientific paper: we report the investigation of conductance fluctuation and shot noise in disordered graphene systems with two kinds of disorder , anderson type impurities and random dopants . to avoid the brute - force calculation which is time consuming and impractical at low doping concentration
, we develop an expansion method based on the coherent potential approximation ( cpa ) to calculate the average of four green s functions and the results are obtained by truncating the expansion up to 6th order in terms of single - site - t - matrix " .
since our expansion is with respect to single - site - t - matrix " instead of disorder strength @xmath0 , good result can be obtained at 6th order for finite @xmath0 .
we benchmark our results against brute - force method on disordered graphene systems as well as the two dimensional square lattice model systems for both anderson disorder and the random doping .
the results show that in the regime where the disorder strength @xmath0 is small or the doping concentration is low , our results agree well with the results obtained from the brute - force method .
specifically , for the graphene system with anderson impurities , our results for conductance fluctuation show good agreement for @xmath0 up to @xmath1 , where @xmath2 is the hopping energy . while for average shot noise
, the results are good for @xmath0 up to @xmath3 .
when the graphene system is doped with low concentration @xmath4 , the conductance fluctuation and shot noise agrees with brute - force results for large @xmath0 which is comparable to the hopping energy @xmath2 . at large doping concentration @xmath5
, good agreement can be reached for conductance fluctuation and shot noise for @xmath0 up to @xmath1 .
we have also tested our formalism on square lattice with similar results .
our formalism can be easily combined with linear muffin - tin orbital first - principles transport calculations for light doping nano - scaled systems , making prediction on variability of nano - devices . .
And you have already written the first three sentences of the full article: in nano - electronics , quantitative evaluation of impurity effects is crucial because device properties are strongly influenced by or even built on such effects .
experimentally , the impurities exist and can be doped in nano - devices without knowing their exact locations , so theoretically it is important to predict the averaged transport quantities such as conductance over impurity configurations . the most direct way to obtain the averaged conductance is to generate many different configurations , then calculate the conductance for each configuration , and finally take the mean value .
such a brute - force method is usually used in the mesoscopic systems from diffusive regime to localized regime because it is an exact calculation ..
Please generate the next two sentences of the article | but in order to get good statistics , huge number of configurations has to be generated making it very time - consuming especially for the calculation of conductance fluctuation . when the disorder strength is weak , it is not necessary to use the brute - force method since some analytic approximate method is superior in speed while maintaining the same accuracy . for
this purpose considerable effort has been made to develop approximate techniques , within which the most widely used technique is the coherent potential approximation ( cpa ) , which is a useful tool to evaluate the configurational averaged one - electron green s function@xcite @xmath6 , and has also been extended to determine the so - called |
3,183 | Suppose that you have an abstract for a scientific paper: we combine _ spitzer _ irac mid - infrared and _ chandra _ x - ray observations of the dominant galaxies ngc6872 and ngc6876 in the pavo group with archival optical and hi data to study interaction - induced star formation
. in the spiral galaxy ngc6872 , @xmath0 and @xmath1 nonstellar emission having colors consistent with polycyclic aromatic hydrocarbons ( pahs ) is concentrated primarily in clumps in three regions : in a @xmath2kpc radius outer ring about the center of the spiral galaxy , in a bridge of emission connecting ngc6872 s northern spiral arm to ic4970 , and along the full extent of both ngc6872 s tidal arms .
pah emission is correlated with young star clusters and dense hi regions .
we find no strong differences in the mid - infrared colors of the star - forming regions in the spiral galaxy ngc6872 as a function of position relative to the tidally interacting companion galaxy ic4970 .
we find eleven very luminous x - ray sources ( @xmath3ergs@xmath4 ) clustered to the southwest in ngc6872 , near bright star - forming regions . in ngc6872
s tidal features , young star clusters form at the boundaries of diffuse x - ray gas , suggesting that stars form as gas stripped by the interactions cools .
the nucleus of ngc6872 is a weak x - ray point source with @xmath5kev luminosity of @xmath6ergs@xmath4 , but there is little evidence in the inner @xmath7kpc of ngc6872 for pah emission from recent star formation or nuclear activity .
however , a @xmath8kpc ` stream ' , leading from the outer ring of ngc6872 to the nucleus , may signal the transport of interstellar matter into ngc6872 s nuclear region .
nonstellar emission , consistent with pah emission , is also found in the central region of elliptical galaxy ngc6877 , companion to the dominant pavo group elliptical galaxy ngc6876 .
however , in the central region of ngc6876 , the dust emission is more likely due to silicate emission from old agb stars . .
And you have already written the first three sentences of the full article: galaxy collisions and mergers have long been known to influence star formation in galaxies ( see , e.g. , the review by struck 1999 and references therein ) and likely play a fundamental role in the transformation of the population of gas - rich spiral galaxies at high redshift into the spheroidal and elliptical galaxies that dominate dense galaxy groups and clusters at the present epoch .
probing the details of the gravitational and hydrodynamical processes that affect star formation during these collisions has only recently become possible with the advent of high spatial resolution observations that are capable of resolving star - forming complexes within nearby galaxies across the full electromagnetic spectrum ( radio to x - ray ) , and that allow us to measure the thermodynamic properties of cold and hot gas in and around these galaxies .
early studies of star formation in interacting galaxies were based primarily on observations in the optical and far - infrared wavebands ..
Please generate the next two sentences of the article | these studies focused on global star formation properties and correlations between observable star formation indicators .
for example , kennicutt et al . |
3,184 | Suppose that you have an abstract for a scientific paper: we present a study of the kinematics of the remote globular cluster ngc 5694 based on giraffe@vlt medium resolution spectra .
a sample of 165 individual stars selected to lie on the red giant branch in the cluster color magnitude diagram was considered . using radial velocity and metallicity from calcium triplet
, we were able to select 83 bona - fide cluster members .
the addition of six previously known members leads to a total sample of 89 cluster giants with typical uncertainties @xmath0 km / s in their radial velocity estimates .
the sample covers a wide range of projected distances from the cluster center , from @xmath1 to @xmath2 half - light radii ( @xmath3 ) .
we find only very weak rotation , as typical of metal - poor globular clusters .
the velocity dispersion gently declines from a central value of @xmath4 km / s to @xmath5 km / s at @xmath6 , then it remainins flat out to the next ( and last ) measured point of the dispersion profile , at @xmath7 , at odds with the predictions of isotropic king models .
we show that both isotropic single - mass non - collisional models and multi - mass anisotropic models can reproduce the observed surface brightness and velocity dispersion profiles .
[ firstpage ] ( galaxy : ) globular clusters : individual : ngc 5694 stars : abundances .
And you have already written the first three sentences of the full article: ngc 5694 is a bright ( @xmath8 ) and remote ( @xmath9 kpc ) old and metal - poor galactic globular cluster ( gc ) , located in the hydra constellation .
first discovered by w. herschel in 1784 , it has been recognised as a gc by @xcite .
because of its distance and low apparent magnitude , the first photometric studies of giant stars in this cluster have been conducted only in relatively recent epoch @xcite ..
Please generate the next two sentences of the article | after the first integrated spectroscopic studies ( see , e.g. , * ? ? ?
* ) spectroscopy of individual red giant stars in ngc 5694 have been carried out by @xcite and , more recently , by @xcite . |
3,185 | Suppose that you have an abstract for a scientific paper: in this work we conclude the analysis of our co line survey of luminous infrared galaxies ( lirgs : @xmath0@xmath110@xmath2l@xmath3 ) in the local universe ( paperi ) , by focusing on the influence of their average ism properties on the total molecular gas mass estimates via the so - called @xmath4=@xmath5 factor .
one - phase radiative transfer models of the global co spectral line energy distributions ( sleds ) yield an @xmath6 distribution with : @xmath7@xmath8@xmath9@xmath10(kkms@xmath11pc@xmath12)@xmath11 over a significant range of average gas densities , temperatures and dynamical states .
the latter emerges as the most important parameter in determining @xmath4 , with unbound states yielding low values and self - gravitating states the highest ones .
nevertheless in many ( u)lirgs where available higher - j co lines ( j=32 , 43 , and/or j=65 ) or hcn line data from the literature allow a separate assesment of the gas mass at high densities ( @xmath1310@xmath14@xmath15 ) rather than a simple one - phase analysis we find that _ near - galactic @xmath16@xmath17(3 - 6)@xmath18(kkms@xmath11pc@xmath12)@xmath11 values become possible .
_ we further show that in the highly turbulent molecular gas in ulirgs a high - density component will be common and can be massive enough for its high @xmath4 to dominate the average value for the entire galaxy . using solely low - j co lines to constrain @xmath6 in such environments ( as it has been the practice up to now )
may have thus resulted to _
systematic underestimates of molecular gas mass in ulirgs _ as such lines are dominated by a warm , diffuse and unbound gas phase with low @xmath4 but very little mass .
only well - sampled high - j co sleds ( j=32 and higher ) and/or multi - j observations of heavy rotor molecules ( e.g. hcn ) can circumvent such a bias , and the latter type of observations may have actually provided early evidence of it in local ulirgs . the only way that the global @xmath19 of such systems could be significantly lower than....
And you have already written the first three sentences of the full article: soon after the discovery of the luminous infrared galaxies ( lirgs ) , whose bolometric luminosities are dominated by the infrared part of their spectral energy distributions ( seds ) ( @xmath27@xmath2810@xmath2l@xmath23 ) ( e.g. soifer et al .
1987 ) , single dish and interferometric co j=10 , 21 line observations were used to determine their total molecular gas mass and its distribution ( sanders et al .
1988a ; tinney et al . 1990 ; wang et al ..
Please generate the next two sentences of the article | 1991 ; sanders et al . 1991 ; solomon et al . 1997 ; downes & solomon 1998 ; bryant & scoville 1996 , 1999 ) .
these efforts were paralleled by several investigations of the so - called @xmath4=m(h@xmath29)/@xmath30(10 ) factor and its dependance on the average ism conditions both theoretical ( dickman et al . 1988 ; maloney & black 1988 ; wolfire et al . 1993 ; sakamoto 1996 ; bryant & scoville 1996 ; wall 2007 ) and observational ( e.g. israel 1988 , 1993 , 1997 ; solomon et al . |
3,186 | Suppose that you have an abstract for a scientific paper: molecular networks act as the backbone of cellular activities , providing an excellent opportunity to understand the developmental changes in an organism .
while network data usually constitute only stationary network graphs , constructing multilayer ppi network may provide clues to the particular developmental role at each stage of life and may unravel the importance of these developmental changes .
the developmental biology model of _ caenorhabditis elegans _ analyzed here provides a ripe platform to understand the patterns of evolution during life stages of an organism . in the present study ,
the widely studied network properties exhibit overall similar statistics for all the ppi layers .
further , the analysis of the degree - degree correlation and spectral properties not only reveals crucial differences in each ppi layer but also indicates the presence of the varying complexity among them .
the ppi layer of nematode life stage exhibits various network properties different to rest of the ppi layers , indicating the specific role of cellular diversity and developmental transitions at this stage .
the framework presented here provides a direction to explore and understand developmental changes occurring in different life stages of an organism . * a multilayer ppi network analysis of different life stages in c. elegans * + pramod shinde@xmath0 , and sarika jalan@xmath1 + _ @xmath2 centre for biosciences and biomedical engineering , indian institute of technology indore , simrol , indore 452020 , india + _ @xmath3 complex systems lab , discipline of physics , indian institute of technology indore , simrol , indore 452020 , india + e - mail : [email protected] , @[email protected] _ _
recent developments in the quantitative analysis of complex networks have rapidly been translated to studies of different biological network organizations @xcite .
developmental biology is the study of the molecular and cellular events that lead to the generation of a multicellular....
And you have already written the first three sentences of the full article: after extracting the names of proteins occurring in a particular life stage of _ caenorhabditis elegans _ , experimentally verified protein - protein interactions are collected from various bioinformatics repositories @xcite .
next , six different ppi networks are constructed by treating each life stage as a layer of the multilayer ppi network ( fig .
[ fig1 ] ) . for each layer , all the proteins are enlisted and these proteins are occurring for their functional or structural activities in that life stage ..
Please generate the next two sentences of the article | the proteins are the nodes and connections are assigned if a pair of proteins @xmath5 and @xmath6 has an interaction between them .
thus , six different sub - networks for multilayer ppi network are obtained . |
3,187 | Suppose that you have an abstract for a scientific paper: we study the linearized fpl
von karman theory of a long , thin rectangular elastic membrane that is bent through an angle @xmath0 .
we prove rigorous bounds for the minimum energy of this configuration in terms of the plate thickness @xmath1 and the bending angle .
we show that the minimum energy scales as @xmath2 .
this scaling is in sharp contrast with previously obtained results for the linearized theory of thin sheets with isotropic compression boundary conditions , where the energy scales as @xmath1 . .
And you have already written the first three sentences of the full article: everyday experience tells us that thin elastic sheets _ crumple _ , when confined into a small volume , _ e.g. _ a sheet of paper `` confined '' by ones hands .
crumpling also plays an important role in the mechanical behavior of packaging material and in the dissipation of the energy of collisions by the `` crumple zones '' of automobiles .
crumpling is therefore a problem of much intrinsic interest , but understanding this behavior is complicated by the complex morphology of a typical crumpled sheet . despite the complicated appearance of a crumpled sheet ,.
Please generate the next two sentences of the article | the crumpling phenomenon is in itself very robust .
it is easily observed in thin sheets made from a variety of materials , suggesting that it can be studied using simplified or idealized models that capture the essential features of thin elastic sheets . |
3,188 | Suppose that you have an abstract for a scientific paper: we analyze the @xmath0 vertex in the framework of models that add a new bottom quark in a nonsequential way and we evaluate the tree level contribution to the lep / slc observables @xmath1 , @xmath2 and @xmath3 .
we obtain bounds for the mixing angles from the experimentally allowed contour regions of the parameters @xmath4 introduced here . in order to get a more restrictive region ,
we consider the experimental results for @xmath5 as well .
pacs numbers : 12.15.ff , 12.15.-y , 12.15.ji , 12.60.-i .
And you have already written the first three sentences of the full article: the comparison of theoretical predictions with experimental data has confirmed the validity of the standard model ( sm ) in an impressive way .
the quantum effects of the sm have been established at the @xmath6 level , and the direct and indirect determinations of the top quark mass are compatible with each other . in spite of this success , the conceptual situation with the sm is not completely satisfactory for a number of deficiencies .
some of them are the large number of free parameters and the hierarchical fermion masses ..
Please generate the next two sentences of the article | the sm contains three generations of quarks in irreducible representations of the gauge symmetry group @xmath7 .
the possibility of extending them has been studied in different frameworks @xcite-@xcite which are based either on a fourth generation sequential family , or on non - sequential fermions , regularly called exotic representations because they are different from those of the sm . |
3,189 | Suppose that you have an abstract for a scientific paper: we study rotating squeezed quantum states created by a parametric resonance in an open harmonic system . as a specific realization of the phenomenon we study a mesoscopic squid loop where the state preparation procedure is simple in principle and feasible with currently available experimental methods . by solving dynamics and calculating spectral properties
we show that quantum fluctuations of squid observables can be reduced below their groundstate value .
the measurement is introduced by coupling the squid to a transmission line carrying the radiation to a secondary measurement device . besides the theoretical interest , our studies are motivated by an opportunity for a practical quantum noise engineering . .
And you have already written the first three sentences of the full article: at the heart of the quantum theory lies the fundamental principle of describing physically observable quantities as hermitian operators acting on hilbert space of quantum states .
generally these operators do not commute , a trait giving rise to the fundamental uncertainty principle first formulated by heisenberg .
the uncertainty principle characterizes the statistical spread of the distributions corresponding to two different observables ..
Please generate the next two sentences of the article | if the operators representing the observables do not commute , the statistical variations of their observed distributions , frequently called uncertainties , can not generally be arbitrarily small in a given state . however , the statistical variation of a single observable is not limited in any way by the uncertainty principle . for
two given non - commuting observables , a state in which the lower limit of the uncertainty principle is reached is called a minimum uncertainty state . decreasing the uncertainty with respect to one observable results in the increase of the uncertainty of the other . |
3,190 | Suppose that you have an abstract for a scientific paper: counter - propagating light fields have the ability to create self - organized one - dimensional optically bound arrays of microscopic particles , where the light fields adapt to the particle locations and vice versa .
we develop a theoretical model to describe this situation and show good agreement with recent experimental data ( phys .
rev .
lett .
89 , 128301 ( 2002 ) ) for two and three particles , if the scattering force is assumed to dominate the axial trapping of the particles .
the extension of these ideas to two and three dimensional optically bound states is also discussed . .
And you have already written the first three sentences of the full article: the ability of light to influence the kinetic motion of microscopic and atomic matter has had a profound impact in the last three decades .
the optical manipulation of matter was first seriously studied by ashkin and co - workers in the 1970s @xcite , and led ultimately to the demonstration of the single beam gradient force trap @xcite , referred to as optical tweezers , where the gradient of an optical field can induce dielectric particles of higher refractive index than their surrounding medium to be trapped in three dimensions in the light field maxima @xcite .
much of ashkin s early work centered not on gradient forces , but on the use of radiation pressure to trap particles @xcite , and a dual beam radiation pressure trap was demonstrated in a which single particle was confined ..
Please generate the next two sentences of the article | this work ultimately contributed to the development of the magneto - optical trap for neutral atoms @xcite .
recently we observed one - dimensional _ arrays _ of silica spheres trapped in a dual beam radiation pressure trap @xcite . |
3,191 | Suppose that you have an abstract for a scientific paper: let @xmath0 be a planar graph with no two 3-cycles sharing an edge . we show
that if @xmath1 , then @xmath2 and @xmath3 we also show that if @xmath4 , then @xmath5 and if @xmath6 , then @xmath7 . all of these results extend to graphs in the projective plane and when @xmath6 the results also extend to graphs in the torus and klein bottle .
this second edge - choosability result improves on work of wang and lih and of zhang and wu .
all of our results use the discharging method to prove structural lemmas about the existence of subgraphs with small degree - sum .
for example , we prove that if @xmath0 is a planar graph with no two 3-cycles sharing an edge and with @xmath6 , then @xmath0 has an edge @xmath8 with @xmath9 and @xmath10 .
all of our proofs yield linear - time algorithms that produce the desired colorings
. _ msc _ : 05c15 , 05c10 * keywords * : list coloring , edge coloring , total coloring , vizing s conjecture # 1 # 1 .
And you have already written the first three sentences of the full article: all our graphs are finite and without loops or multiple edges .
let @xmath0 be a plane graph .
we use @xmath11 , @xmath12 , @xmath13 , @xmath14 , and @xmath15 to denote the edge set , vertex set , face set , maximum degree , and minimum degree of @xmath0 , respectively ..
Please generate the next two sentences of the article | when the graph is clear from context , we use @xmath16 , rather than @xmath14 .
we use `` @xmath17-face '' and `` @xmath17-vertex '' to mean faces and vertices of degree @xmath17 . |
3,192 | Suppose that you have an abstract for a scientific paper: we carry out a study of intermediate - mass ( between 1 and 2.5 gev ) dilepton spectra from hadronic interactions in heavy - ion collisions .
the processes considered are @xmath0 , @xmath1 , @xmath2 , @xmath3 , @xmath4 , and @xmath5 .
the elementary cross sections for those are obtained from chiral lagrangians involving pseudoscalar , vector , and axial - vector mesons .
the respective electromagnetic form factors are determined by fitting to experimental data for the reverse processes of @xmath6 .
based on this input we calculate cross sections and thermal dilepton emission rates and compare our results with those from other approaches .
finally we use these elementary cross sections with a relativistic transport model and calculate dilepton spectra in s+w collisions at sps energies .
the comparison of our results with experimental data from the helios-3 collaboration indicates the importance of the secondary hadronic contributions to the intermediate - mass dilepton spectra . .
And you have already written the first three sentences of the full article: the experimental measurement and theoretical investigation of dilepton production constitute one of the most active and exciting fields in the physics of relativistic nuclear collisions @xcite .
because of their relatively weak final - state interactions with the hadronic environment , dileptons , as well as photons , are considered ideal probes of the early stage of heavy - ion collisions , where quark - gluon - plasma ( qgp ) formation is expected @xcite .
because of an additional variable , the invariant mass @xmath7 , dileptons have the advantage of a better signal to background ratio than real photons @xcite ..
Please generate the next two sentences of the article | they of course also prove superior in processes involving two - body annihilations .
dilepton mass spectra produced in heavy ion collisions can basically be divided into three regions . |
3,193 | Suppose that you have an abstract for a scientific paper: the dynamical equations of clarinet - like systems are known to be reducible to a non - linear iterated map within reasonable approximations .
this leads to time oscillations that are represented by square signals , analogous to the raman regime for string instruments . in this article
, we study in more detail the properties of the corresponding non - linear iterations , with emphasis on the geometrical constructions that can be used to classify the various solutions ( for instance with or without reed beating ) as well as on the periodicity windows that occur within the chaotic region . in particular
, we find a regime where period tripling occurs and examine the conditions for intermittency .
we also show that , while the direct observation of the iteration function does not reveal much on the oscillation regime of the instrument , the graph of the high order iterates directly gives visible information on the oscillation regime ( characterization of the number of period doubligs , chaotic behaviour , etc . ) .
keywords : bifurcations , iterated maps , reed musical instruments , clarinet , acoustics . .
And you have already written the first three sentences of the full article: non - linear iterated maps are now known as an universal tool in numerous scientific domains , including for instance mechanics , hydrodynamics and economy @xcite @xcite @xcite .
they often appear because the differential equations describing the dynamics of a system can be reduced to non - linear iterations , with the help of poincar recurrence maps for instance .
the resulting iterations combine a great mathematical simplicity , which makes them convenient for numerical simulations , with a large variety of interesting behaviors , providing generic information on the properties of the system . in particular , they are essential to characterize one of the routes to chaos , the cascade of period doublings @xcite . in musical acoustics , mc intyre _.
Please generate the next two sentences of the article | et al . _ have given , in a celebrated article @xcite , a general frame for calculating the oscillations of musical instruments , based upon the coupling of a linear resonator and a non - linear excitator ( for reed instruments , the flow generated by a supply pressure in the mouth and modulated by a reed ) .
in an appendix of their article they show that , within simplified models of self - sustained instruments , the equations of evolution can also be reduced to an iterated map with appropriate non - linear functions . for resonators with a simple shape such as a uniform string or a cylindrical tube , |
3,194 | Suppose that you have an abstract for a scientific paper: we present observations of a new low - mass double - lined eclipsing binary system discovered using repeat observations of the celestial equator from the sloan digital sky survey ii .
using near - infrared photometry and optical spectroscopy we have measured the properties of this short - period [ @xmath0=0.407037(14 ) d ] system and its two components .
we find the following parameters for the two components : m@xmath1 , r@xmath2 , m@xmath3 , r@xmath4 , @xmath5k , @xmath6k .
the masses and radii of the two components of this system agree well with theoretical expectations based on models of low - mass stars , within the admittedly large errors .
future synoptic surveys like pan - starrs and lsst will produce a wealth of information about low - mass eclipsing systems and should make it possible , with an increased reliance on follow - up observations , to detect many systems with low - mass and sub - stellar companions . with the large numbers of objects for which these surveys will produce high - quality photometry , we suggest that it becomes possible to identify such systems even with sparse time sampling and a relatively small number of individual observations . .
And you have already written the first three sentences of the full article: studies of detached , double - lined eclipsing binary systems ( debs ) allow for direct measurements of the masses and radii of stars .
these measurements have direct implications for theories of stellar structure and evolution .
our understanding of the structure of stars on the lower main sequence has improved over the past decade , but relatively few direct measurements of stellar mass and radius exist for objects with masses @xmath7 ..
Please generate the next two sentences of the article | measurements of stars in this mass range allow us to test models of stellar structure where they are least well constrained by observation .
there are four known main sequence debs inhabiting this mass range and the properties of these systems are well - measured ( @xcite , @xcite , @xcite , @xcite ) . in order to refine physical models of low - mass stars , more systems must be discovered and studied . |
3,195 | Suppose that you have an abstract for a scientific paper: we study the thermodynamic properties of spin chains of haldane shastry type associated with the @xmath0 root system in the presence of a uniform external magnetic field . to this end
, we exactly compute the partition function of these models for an arbitrary finite number of spins .
we then show that these chains are equivalent to a suitable inhomogeneous classical ising model in a spatially dependent magnetic field , generalizing the results of basu - mallick et al .
for the zero magnetic field case . using the standard transfer matrix approach , we are able to compute in closed form the free energy per site in the thermodynamic limit . we perform a detailed analysis of the chains thermodynamics in a unified way , with special emphasis on the zero field and zero temperature limits .
finally , we provide a novel interpretation of the thermodynamic quantities of spin chains of haldane shastry type as weighted averages of the analogous quantities over an ensemble of classical ising models .
spin chains of haldane shastry type , vertex models , transfer matrix method , thermodynamic limit .
And you have already written the first three sentences of the full article: in this paper we study a class of @xmath1 spin chains whose hamiltonian can be collectively written as @xmath2 where the @xmath3 s are real constants and the interactions @xmath4 are chosen as described below ( see eqs .
( 1.7 ) ) . in the previous formula , the operators @xmath5 act on a state @xmath6 of the canonical spin basis by permuting the @xmath7-th and @xmath8-th spins : @xmath9 the permutation operators @xmath5 can be expressed in terms of the ( hermitian ) @xmath1 spin operators @xmath10 with the normalization @xmath11 ( where the subindex @xmath12 labels the chain sites ) as @xcite @xmath13 let @xmath14 denote the operator whose action on the canonical spin basis is given by @xmath15 so that the operators @xmath16 span the standard cartan subalgebra of @xmath1 .
the operators @xmath17 are then defined by @xmath18 thus the second sum in eq ..
Please generate the next two sentences of the article | can be interpreted as arising from the interaction with a uniform external @xmath1 `` magnetic '' field magnetic field term is of the form @xmath19 , where @xmath20 is a traceless hermitian matrix acting on the internal space of the @xmath7-th spin . by performing a rotation in this internal space we can diagonalize the matrix @xmath21 , effectively replacing it by a traceless diagonal matrix .
the latter matrix can in turn be expressed in the form @xmath22 , which yields the last term in eq . . |
3,196 | Suppose that you have an abstract for a scientific paper: in reconstructing the top quark momentum from its decay products , one must account for extra jets that can result from radiation of gluons . in this paper
we study soft gluon radiation in top production and decay at the fermilab tevatron .
we consider the cases where one or both @xmath0 bosons decays hadronically , _
i.e. _ , where at least one of the top quarks can be fully reconstructed .
we show results for gluon distributions at the tevatron and find that radiation from the @xmath0 decay products contributes substantially in the central region .
ur-1452 + dtp/96/08 + hep - ph/9605369 + may 1996 + 1.cm * soft gluon radiation in top events : effect of hadronic @xmath0 decays * 1.cm bond masuda , lynne h. orr .2 cm _ department of physics , university of rochester + rochester , ny 14627 - 0171 , usa _
+ .4 cm and .4 cm w.j . stirling .2 cm _ departments of physics and mathematical sciences , university of durham + durham dh1 3le , england _ + .
And you have already written the first three sentences of the full article: the top quark s existence is now well established @xcite and top searches have given way to top studies . in measuring the top quark s properties in particular , its mass radiated gluons can play an important role .
this is due not only to the relatively high probability that @xmath1 events are accompanied by additional gluon jets , but also to the fact that gluons can be radiated in both the top production and decay processes .
this can complicate top momentum reconstruction , leading to ambiguities in identifying the top quark s decay products , increased systematic uncertainties , or both ..
Please generate the next two sentences of the article | these effects in turn influence any measurement based on momentum reconstruction , and may also bias event selection based on identifying top events via invariant mass cuts .
therefore it is necessary to understand the distributions of radiated gluons in top quark events . |
3,197 | Suppose that you have an abstract for a scientific paper: we examine the _ kepler _ light curves of v1504 cyg and v344 lyr , encompassing @xmath0736 d at 1 min cadence . during this span
each system exhibited @xmath0@xmath1 outbursts , including six superoutbursts .
we find that , in both systems , the normal outbursts lying between two superoutbursts increase in duration over time by a factor @[email protected] , and then reset to a small value after the following superoutburst . in both systems
the trend of quiescent intervals between normal outbursts is to increase to a local maximum about half way through the supercycle @xmath2 the interval from one superoutburst to the next @xmath2 and then to decrease back to a small value by the time of the next superoutburst .
this is inconsistent with osaki s thermal - tidal model , which predicts a monotonic increase in the quiescent intervals between normal outbursts during a supercycle .
also , most of the normal outbursts have an asymmetric , fast - rise / slower - decline shape , which would be consistent with outbursts triggered at large radii . the exponential rate of decay of the plateau phase of the superoutbursts is 8 d mag@xmath3 for v1504 cyg and 12 d mag@xmath3 for v344 lyr .
this time scale gives a direct measure of the viscous time scale in the outer accretion disk given the expectation that the entire disk is in the hot , viscous state during superoutburst .
the resulting constraint on the shakura - sunyaev parameter , @xmath4 , is consistent with the value inferred from the fast dwarf nova decays . by looking at the slow decay rate for superoutbursts , which occur in systems below the period gap , in combination with the slow decay rate in one long outburst above the period gap ( in u gem ) , we infer a steep dependence of the decay rate on orbital period for long outbursts .
we argue that this relation implies a steep dependence of @xmath5 on orbital period , which may be consistent with recent findings of patterson , and is consistent with tidal torquing as being the dominant angular....
And you have already written the first three sentences of the full article: cataclysmic variables ( cvs ) are semi - detached interacting binaries in which a roche lobe filling k or m secondary transfers matter to a white dwarf ( wd ) .
cvs evolve to shorter orbital periods and show a `` gap '' between @xmath6 and 3 ( where @xmath7 hr ) during which time the secondary star loses contact with its roche lobe and mass transfer ceases . thus the binary becomes fully detached . at @xmath6
the secondary comes back into contact with its roche lobe and mass transfer resumes . for @xmath8 angular momentum loss from the binary.
Please generate the next two sentences of the article | is thought to be due solely to gravitational radiation .
the cv subclass of dwarf novae ( dne ) are characterized by their semi - periodic outbursts . |
3,198 | Suppose that you have an abstract for a scientific paper: it is well known that one can map certain properties of random matrices , fermionic gases , and zeros of the riemann zeta function to a unique point process on the real line @xmath0 . here
we analytically provide exact generalizations of such a point process in @xmath1-dimensional euclidean space @xmath2 for any @xmath1 , which are special cases of determinantal processes .
in particular , we obtain the @xmath3-particle correlation functions for any @xmath3 , which completely specify the point processes in @xmath2 .
we also demonstrate that spin - polarized fermionic systems in @xmath2 have these same @xmath3-particle correlation functions in each dimension .
the point processes for any @xmath1 are shown to be hyperuniform , i.e. , infinite wavelength density fluctuations vanish , and the structure factor ( or power spectrum ) @xmath4 has a nonanalytic behavior at the origin given by @xmath5 ( @xmath6 ) .
the latter result implies that the pair correlation function @xmath7 tends to unity for large pair distances with a decay rate that is controlled by the power law @xmath8 , which is a well - known property of bosonic ground states and more recently has been shown to characterize maximally random jammed sphere packings .
we graphically display one- and two - dimensional realizations of the point processes in order to vividly reveal their repulsive " nature .
indeed , we show that the point processes can be characterized by an effective hard - core " diameter that grows like the square root of @xmath1 .
the nearest - neighbor distribution functions for these point processes are also evaluated and rigorously bounded . among other results
, this analysis reveals that the probability of finding a large spherical cavity of radius @xmath9 in dimension @xmath1 behaves like a poisson point process but in dimension @xmath10 , i.e. , this probability is given by @xmath11 $ ] for large @xmath9 and finite @xmath1 , where @xmath12 is a positive @xmath1-dependent constant .
we also show that as....
And you have already written the first three sentences of the full article: it is well known that there is a remarkable connection between the statistical properties of certain random hermitian matrices , the zeros of the riemann zeta function , and fermionic gases @xcite .
underlying each of these objects are certain one - dimensional point processes ( defined more precisely in section 2 ) whose statistical properties ( under certain limits ) are believed to be identical .
the purpose of this paper is to provide generalizations of this unique point process to point processes in @xmath1-dimensional euclidean space @xmath2 for any @xmath1 , and to characterize their spatial statistics exactly ..
Please generate the next two sentences of the article | since the characterization of a point process can be viewed as the study of a system of interacting point " particles , exact descriptions of nontrivial point processes in arbitrary space dimension , which are hard to come by @xcite , are of great value in the field of statistical mechanics .
there are three prominent theories of random hermitian matrices , which model the hamiltonians of certain random dynamical systems ; see the excellent book by mehta @xcite . if the dynamical system is symmetric under time reversal , then the relevant theory for integral spin is that of the gaussian orthogonal ensemble ( goe ) or the gaussian symplectic ensemble ( gse ) for half - integer spin . on the other hand , the gaussian unitary ensemble ( gue ) models random hamiltonians without time reversal symmetry , which is relevant to certain properties of the riemann zeta function . |
3,199 | Suppose that you have an abstract for a scientific paper: we describe a study in which introductory physics students engage in reflection with peers about problem solving .
the recitations for an introductory physics course with 200 students were broken into the peer reflection " ( pr ) group and the traditional group .
each week in recitation , students in the pr group reflected in small teams on selected problems from the homework and discussed why solutions of some students employed better problem solving strategies than others .
the graduate and undergraduate teaching assistants ( tas ) in the pr group recitations provided guidance and coaching to help students learn effective problem solving heuristics . in the recitations for the traditional group ,
students had the opportunity to ask the graduate ta questions about the homework before they took a weekly quiz .
the traditional group recitation quiz questions were similar to the homework questions selected for peer reflection " in the pr group recitations .
as one measure of the impact of this intervention , we investigated how likely students were to draw diagrams to help with problem solving . on the final exam with only multiple - choice questions ,
the pr group drew diagrams on more problems than the traditional group , even when there was no external reward for doing so .
since there was no partial credit for drawing the diagrams on the scratch books , students did not draw diagrams simply to get credit for the effort shown and must value the use of diagrams for solving problems if they drew them .
we also find that , regardless of whether the students belonged to the traditional or pr groups , those who drew more diagrams for the multiple - choice questions outperformed those who did not draw them .
2em -0.25 in 6.9 in 9.62 in 1ex -.75 in .
And you have already written the first three sentences of the full article: students must learn effective problem solving strategies in order to develop expertise in physics . specifically , they must be able to solve problems beyond those that can be solved using a plug - and - chug approach .
@xcite research shows that converting a problem from the initial verbal representation to other suitable representations such as diagrammatic , tabular , graphical or algebraic can make further analysis of the problem easier .
@xcite similarly , using analogies or considering limiting cases are also useful strategies for solving problems ..
Please generate the next two sentences of the article | @xcite many traditional courses do not explicitly teach students effective problem solving heuristics .
rather , they may implicitly reward inferior problem solving strategies that many students engage in . |
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