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Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: smc 3 is one of the symbiotic systems in the magellanic clouds . the system contains a wd and an m giant with an orbital period of 4.5 years ( eg . it is a supersoft x - ray source powered by a steady hydrogen burning on the surface of the white dwarf ( orio _ et al . _ 2007 ) . because the system contains a massive white dwarf ( [email protected] m@xmath1 ; orio _ et al . _ @xcite ) with a high accretion rate ( @xmath2 m@xmath1/yr ; kahabka @xcite ) it is considered as one of the most promising supernova ia progenitors among the known symbiotic population . to estimate the mass of the red giant we used the fact that it pulsates with a period of 110 days ( kahabka @xcite ) . smc 3 lies on the sequence b in the k - log(p ) plane ( wood 2000 ) which suggests the first overtone pulsation . assuming the pulsation constant of q=0.04 we derived the mass of 2.3@xmath3 m@xmath1 . to carry out our analysis we used the startrack population synthesis code ( belczyski _ et al . _ the code includes the wind accretion through bondi - hoyle mechanism , roche - lobe overflow , @xmath4 roche - lobe overflow and @xmath5 roche - lobe overflow . as initial conditions we adopted the current parameters of the system and then we modeled its future evolution . we assumed @xmath6=1.44 m@xmath1 and , since we studied the system in the sn ia context , a co wd . for all of our models the system went trough a common envelope ( ce ) after @xmath7 yrs and for none of the models system wd managed to accumulate enough matter to become a type ia supernova . the orbital separation after the ce was relatively big ( a@xmath8r@xmath1 ) , which makes a merger in the hubble time unlikely . the obtained parameters of the system are presented in fig . we predict that the system will not become a type ia supernova in contrary to what was suggested in the literature ( orio _ et al . _ the caveat is that our predicted mass transfer rate is somewhat lower then the one expected for the steady hydrogen burning on the surface of the white dwarf ( nomoto _ et al . _ a lower @xmath9 then expected could be due to the fact that our model underestimates the rg mass loss trough wind by treating it as in the single star scenario , whereas there is a strong observational evidence that this wind is significantly enhanced due to tidal interactions in syst ( mikoajewska _ et al . _ large roche lobe filling factor suggests ellipsoidal variability in the system . 99 belczyski k. 2008 , apjs , 174 , 223 kahabka p. , 2004 , a&a , 416 , 57 kato m. 2013 , apj , 763 , 5 nomoto k. 2007 , apj , 663 , 1269 mikoajewska j. 2002 , adspr , 30 , 2045 orio m. 2007 , apj , 661 , 1105 wood p.r . , 2000 , pasa , 17 , 18
Abstract: | [
"smc 3 is one of the most interesting symbiotic stars . this binary contains a bright k - type giant transferring mass to a massive white dwarf comanion , which makes it is a very promising sn ia candidate . we discuss the evolutionary status of the system using results of population synthesis code ."
] | 626 | 626 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: the distant globular cluster palomar 13 has been found to have a very high m / l ratio of @xmath0 and its profile can be well fitted either by a king profile with a power - law tail or a nfw model [ 1 ] with scale radius @xmath1pc and central density @xmath2 . a possible explanation is that this distant cluster @xmath3 is one of the numerous dark clumps predicted by cdm scenarios , which was not destroyed by the galactic tidal field . it may be a disrupted cluster as well , out of dynamical equilibrium . here we assume that the nfw profile is the signature of a halo made of cold particles . physics beyond the standard model could be supersymmetry . the lowest massive supersymmetric particle , i.e. the neutralino , is a natural candidate for cdm . if r - parity is conserved the neutralino is stable , is its own antiparticle and has a very small cross - section for annihilation . we assume that the halo of palomar 13 is made of neutralinos and calculate the flux in high energy @xmath4-rays due to their annihilation . theoretical physics beyond the standard model is reviewed by j. ellis in this book . the susy benchmark models have been proposed to provide a common way of comparing the discovery potential of future accelerators [ 2 ] . these scenarios correspond to 13 configurations of the 5 msugra parameters with the trilinear coupling parameter @xmath5 set to 0 . the models fulfill the conditions imposed by lep measurements , @xmath6 result and relic density constraint @xmath7 . we calculate the @xmath4 fluxes for the benchmark models bcgil in the `` bulk '' region with our current mc simulation programs : darksusy [ 3 ] and suspect [ 4 ] . the simultaneous use of the suspect and darksusy package allows to perform the rge evolution from the gut scale to the ewsb scale . the fluxes ( in @xmath8 ) obtained by varying the threshold energy and integrated within @xmath9 are shown in the following figure . the main points are that we need to work at low energy threshold and very low flux @xmath10 . these fluxes are not out of reach but ground - based ongoing instruments will have to be improved by one order of magnitude for that purpose . an array of 5 hesses ( each including four 15-m class telescopes like in hess ) , operating in adjacent areas at 5000 m altitude , would reach a flux limit of @xmath11 at 25 gev in 400 h. * with that flux limit most of the neutralino parameter space in the galactic center could be explored . this is roughly the instrument needed to demonstrate or disprove supersymmetry in astrophysics . * p. cot , s.g . djorgovski , g. meylan , s. castro , j.k . mccarthy , 2002 astro - ph/0203410 j. ellis , j.l . feng , a. ferstl , , k.t . matchev , & k. olive , 2001 , astro - ph/0110225 http://www.physto.se/~ edsjo / darksusy/ http://www.lpm.univ - montp2.fr:7082/~ kneur / suspect.html
Abstract: | [
"the distant globular cluster palomar 13 has been found to have a very high mass - to - light ratio and its profile can be well fitted either by a king model with a tail , or with a nfw model [ 1 ] . this cluster may be the first case of the many clumps predicted by cdm simulations that would not be disrupted by the galactic halo potential . we make the hypothesis that pal 13 is made of neutralinos and run the darksuspect code to estimate the high - energy photon flux due to the annihilation of neutralinos through various channels in some benchmark scenarios . these low fluxes may be used as targets to be reached in proposals for future ground - based high altitude cerenkov telescopes ."
] | 615 | 615 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: the polcor instrument is a combined imager , coronograph and polarimeter built for the nordic optical telescope ( not ) . polcor provides sharp images ( resolution down to 02 ) , has a well - defined psf ( resulting in a higher image contrast ) and a high - quality polarimeter . + we observed three sources using polcor / not : the binary s - type agb star w aql , and the two detached shell carbon stars u cam and dr ser . observations of the polarized light around the stars trace the circumstellar dust distribution and thus enables the search for structures and asymmetries in the circumstellar envelope . though this study the geometry of the mass loss can be investigated which will give important clues not only to the processes at play , but also to the transition from the agb phase to the planetary nebula phase . the circumstellar dust distribution around the binary star w aql is mapped and found to be asymmetric , both on large ( 10 ) and on smaller ( 1 ) scales ( fig . 1 ) . the large - scale images show what appears to be a dust - density enhancement on the south - west side of the star and the inner region appears bi - polar through the coronographic mask . these structures are in agreement with what could be expected from binary interaction .
Abstract: | [
"stellar light from an agb star is scattered by the circumstellar dust and polarized in the direction perpendicular to the source . therefore , images of circumstellar envelopes around agb stars in polarized light traces the dust distribution and can be used to search for asymmetries , and to achieve a better understanding of the mechanisms at play when agb stars are transformed into planetary nebulae . the polcor instrument is a combined imager , polarimeter , and coronograph providing images with an angular resolution down to 02 . we have used it to map the dust distribution around three agb stars : w aql , and the detached shell sources dr ser , and u cam . w aql is a binary and we find indications of a bi - polar dust distribution around the star . the observations of the latter two sources clearly reveal the detached shells , likely the result of a brief , strongly enhanced mass - loss rate during the late evolution of these stars . mapping the detached shells gives us clues to the symmetry of the mass loss and important evolutionary processes ."
] | 330 | 330 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: intermediate scale disk galaxies with starbursts are relatively common in the nearby universe . about 5% of galaxies with @xmath017 @xmath1 m@xmath2 @xmath321 have evidence for starbursts . many of these occur in smaller galaxies , produce blue colors and strong emission lines , and are in gas rich systems , as indicated by their relatively large fractional hi content . the more luminous nearby blue starbursts structurally and spectroscopically resemble the faint blue compact narrow emission line galaxies ( cnelgs ) , which become common at redshifts of [email protected] ( e.g. , guzman et al . they are less well - matched to high redshift blue galaxies , which have a combination of high uv luminosities and huge star formation rates that are not common in nearby extreme starbursts . this difference probably reflects secular evolution in the lives of galaxies ; for example , systems at high redshift may be subject to frequent , strong mergers that trigger hyperactive star formation ( e.g. conselice et al . 2001 in prep ) . nearby starbursts frequently show evidence for being dynamically cool , that is they contain strong spiral arms or bars , features that are found in rotationally supported galactic disks . thus the processes that produced these starburst did not severely disrupt the disk , or the disk reformed during the starburst event . local analogs to the cnelgs include profound starbursts arising from minor perturbations ( see figure 1 ) . moderate interactions ( glancing collisions between equals , minor mergers ) are apparently the sources of many starbursts . evidence for this includes subtle optical structural features such as wisps , faint tails , or moderately disturbed kinematics in starbursts , as well as the more ubiquitous signatures of disturbed hi . furthermore , in some starbursts where an interaction is the likely trigger , the outer regions of the optical disk appear to be relatively symmetric and relaxed . three possible explanations for this behavior are : @xmath5 blue starbursts are commonly associated with disk galaxies : near face - on systems can transmit uv light through areas where the disk has been cleaned out by supershells , supernova , etc . ( e.g. conselice et al . 2000 ) . @xmath5 low inclination disks can mimic the kinematics of low mass galaxies due to their narrow line widths ( homeier & gallagher 1999 ) . some intermediate redshift cnelgs could be low inclination disks of moderate mass rather then extreme dwarf starbursts . @xmath5 undisturbed intermediate mass galaxies , such as extreme late - type and superthin spirals ( e.g. , matthews et al . 1998 ) can be inefficient star - formers and thereby store interstellar gas , the fuel for starbursts , over cosmic time scales . @xmath5 uv - bright regions of starbursts frequently occur in features associated with disks , such as rings or arms ( e.g. conselice et al . 2000 ) which may represent star forming environments not yet accessible to severely disturbed high luminosity starbursts in the distant universe . conselice , c.j . 2000 , aj , 119 , 79 + guzman , r. et al . 1998 , apj , 495 , l13 + homeier , n. & gallagher , j.s . 1999 , apj , 522 , 199 + matthews , l. , van driel , w. , & gallagher , j. 1998 . aj , 116 , 1169 + mihos , c. & hernquist , l. 1996 , apj , 464 , 641 +
Abstract: | [
"moderately luminous starbursts in the nearby universe often occur in disk galaxies that are at most subject to mild external perturbations . an investigation of this type of galaxy leads to a better understanding of starburst triggering mechanisms and the resulting star formation processes , and provides useful comparisons to more extreme starbursts seen at high redshifts . # 1_#1 _ # 1_#1 _ = # 1 1.25 in .125 in .25 in"
] | 681 | 681 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: the ultimate fate of the gas which cools in cooling flows is still unknown . a possibility is that a fraction of the gas forms cold molecular clouds @xcite . as a result of fragmentation we expect the formation of small clouds with higher density and possible production of molecules in particular @xmath0 and traces of @xmath1 and @xmath2 . + taking into account radiative transfer effects we computed analytically in @xcite the cooling function @xmath3 for the transition between the ground state and the first rotational level . this way we determined a lower limit of @xmath4 . + meanwhile we improved this calculation by including numerically all rotational transitions which are relevant at low temperatures ( i.e. up to @xmath5 ) . + the following column densities are adopted for a typical small cloud ( with @xmath6@xmath7 ) : @xmath8 , which corresponds to a @xmath2 abundance : @xmath9 . for @xmath1 instead we assume the primordial ratio @xmath10 . + in figure 1 we plotted the molecular cooling function @xmath3 taking into account @xmath2 , @xmath1 and @xmath0 in the range 3 - 300 k. @xmath2 is the main coolant in the range of temperatures 3 - 80 k , @xmath1 in the range 80 - 150 k and @xmath0 dominates above 150 k. the heating is given by the external x - ray flux as produced from the hot intracluster gas . the thermal balance between heating and cooling leads to an equilibrium temperature for the clouds . we have calculated the minimum equilibrium temperature @xmath11 of the clumps inside the cooling flow region . table 1 shows the equilibrium temperature for different clusters . for comparison we give the values we find using our analytical approximation ( @xmath12=1 ) and the ones by taking into account higher excited rotational levels ( @xmath12=5 ) . one clearly sees that the inclusion of the higher excited levels into the calculations lowers the equilibrium temperature , particularly for hot clusters such as for instance abell 478 . + we conclude that thermal equilibrium can be achieved at very low temperatures inside the cooling flow region mainly due to @xmath2-cooling . other molecules than @xmath2 , for example @xmath13 or @xmath14 , could also be important . thus the study of the chemistry in cooling flows might lead to important insight .
Abstract: | [
"in many clusters of galaxies there is evidence for cooling flows which deposit large quantities of cool gas in the central regions . a fraction of this gas might accumulate as dense cool clouds . the aim of this communication is to discuss the minimum temperature achievable by clouds in cooling flows of different clusters of galaxies ."
] | 482 | 482 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: catalogs of galaxy clusters with a large range of redshifts and cluster x - ray luminosities are an ideal basis for the test of cosmological parameters ( e.g. henry 2000 ; borgani et al . 2001 ) and the study of cluster formation and evolution . the bright and southern serendipitous high redshift archival rosat cluster ( sharc ) surveys provide a sample of clusters detected in rosat observations over two decades of x - ray luminosities ( 10@xmath2 l@xmath3erg / s ) with redshifts between 0.2 and 0.8 ( romer et al . 2000 ; collins et al . 1997 ; burke et al . 1997 ) . we present here preliminary results based on the follow - up observations of three of these selected galaxy clusters with xmm newton : rx j0256.5 + 0006 , rx j2237.0 - 1516 and rx j1200.8 - 0328 . for the first time , the new generation of x - ray observatory , like xmm - newton and _ chandra _ give capabilities to do precise spectroscopic and imaging analysis at the same time ( see e.g arnaud et al . 2002a ) . our analysis is based on the three epic cameras , mos1&2 and pn . throughout the paper , we use a cosmology with h@xmath4km / s / mpc , @xmath5 and @xmath6 . the error bars are given with a confidence level of 90% . all the data presented here are treated with the version 5.2 of the sas ( science analysis software ) . we select event patterns and time intervals of low background as described in majerowicz et al . table 1 shows the effective exposure time of our observations after flare rejection . this suggests that this cluster does not host a strong cooling flow . this was already seen in rx j1120.1 + 4318 , a relaxed cluster at z=0.6 ( arnaud et al . 2002a ) also found in the sharc survey . the global temperature for this cluster is 5.1@xmath1kev . its surface brightness profile is fitted by a @xmath7-model and the parameters are : @xmath7=0.64 and @xmath80.51@xmath9228kpc . arnaud , m. , neumann , d.m . , aghanim , n. , et al , 2001 , , 365 , l80 arnaud , m. , majerowicz , s. , lumb , d. , et al , 2002a , in press , astro - ph/0204306 arnaud , m. , 2002b , this issue borgani , s. , rosati , p. , tozzi , p. , et al , 2001 , , 561 , 13 burke , d.j . , collins , c.a . , sharples , r.m . , et al , 1997 , , 488 , l83 collins , c.a . , burke , d.j . , romer , a.k . , et al , 1997 , , 479 , l117 henry , j.p . , 2000 , apj , 534 , 565 lumb , d. , 2002 , xmm - soc - cal - tn-0016 majerowicz , s. , neumann , d.m . & reiprich , t.h . , 2002 , submitted to , astro - ph/0202347 neumann , d.m . & bhringer , h. 1997 , , 289 , 123 roettiger , k. , loken , c. & burns , j.o . , 1997 , , 109 , 307 romer , a.k . , nichol , r.c . , holden , b.p . , et al , 2000 , , 126 , 209 schindler , s. & mller , e. , 1993 , , 272 , 137 snowden , s.l . , egger , r. , freyberg , m.j . , et al , 1997 , , 485 , 125 takizawa , m. , 1999 , , 520 , 514
Abstract: | [
"we present the follow - up of three medium redshift galaxy clusters from the sharc survey observed with xmm newton . we studied rx j0256.5 + 0006 which shows two components which are very likely in interaction . the smallest component exhibits a comet - like structure indicating ram pressure stripping as it falls onto the main cluster . the second cluster , rx j2237.0 - 1516 is an elliptical cluster with a gas temperature of [email protected] . the third cluster , rx j1200.8 - 0328 seems to be in a relaxed state because its shape is regular and we do not see obvious temperature gradient . its mean temperature is 5.1@xmath1kev . # 1_#1 _ # 1_#1 _ = # 1 1.25 in .125 in .25 in"
] | 719 | 719 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: the disk - galaxies are constructed in dynamical equilibrium ( hernquist , 1993 ) and consist of an exponential stellar disk , a bulge with a hernquist profile , and a pseudoisothermal dark halo ( units as in hernquist , 1993 ) . the two merging galaxies approach each other on nearly parabolic orbits at a pericenter distance of 2 scale lengths of the larger disk . the large galaxy is realized with 20000 disk particles , 6666 bulge particles and 40000 halo particles , respectively . the smaller galaxy contains @xmath1 of the mass and of the particles in each component and has a disk scale length of@xmath2 compared to the more massive galaxy . we tested 14 different relative orientations for every mass ratio . the time integration was performed using the special purpose hardware grape . after the remnants settled into equilibrium an artificial image of the remnant was created ( see also heyl , hernquist & spergel , 1994 ) . following the definition of bender , dberreiner & mllenhoff ( 1988 ) we determined the characteristic isophotal shape @xmath3 , ellipticity @xmath4 , the ratio of major axis rotation and central velocity dispersion , @xmath5 , and the anisotropy parameter @xmath6 for 500 random projections of each of the 14 orbital geometries . these values were used to calculate a probability density for a given simulated remnant to be observed at a given location in the two dimensional parameter plane , adopting that mergers occur randomly without any preferred relative inclination . figure 1 shows the result for 1:1 , 2:1 , 3:1 and 4:1 merger remnants . from these results we conclude that most of the global properties of elliptical galaxies can be explained by a sequence of stellar mergers between disk galaxies of mass ratios between 1:1 and 4:1 . 1:1 mergers completely erase the structure of the initial disk . in the 3:1 and 4:1 case the remnants seem to remember their initial state ( see barnes , 1998 ) . in this sense the sequence of mass ratios is a sequence of disk disruption . however , even with 4:1 remnants we fail to reproduce the fastest observed rotators with @xmath7 at one effective radius ( figure 1 ) . recent observations of fast rotating low luminosity ellipticals ( rix , carollo & freeman , 1999 ) show that the disagreement is even stronger at larger radii ( see cretton , naab , rix & burkert , this conference ) barnes , j. , 1998 , in galaxies : interactions and induced star formation , ed . d. friedli , l. mertinet , & d.pfenniger ( saas - fee advanced course lecture notes , no . 26 : berlin : springer ) , 275 bender , r. , dberreiner , s. & mllenhoff , c. , 1988 , , 278 hernquist , l. , 1993 , , 86 , 389 heyl , j. s. , hernquist , l. & spergel , d. n. , 1994 , , 427 , 165 naab , t. , burkert , a. & hernquist , l. , 1999 , , 523 , l133 rix , h. w. , carollo , c. m. & freeman , k. , 1999 , , 513 , l25
Abstract: | [
"collisionless n - body simulations of merging disk - galaxies with mass ratios ( @xmath0 ) of 1:1 , 2:1 , 3:1 , and 4:1 have been performed using direct summation with the special purpose hardware grape . the simulations are used to examine whether the formation of elliptical galaxies can be explained in the context of the merger scenario . the photometric , kinematical and isophotal properties of the merger remnants are investigated and turn out to be in very good agreement with observations of giant elliptical galaxies . we conclude that equal mass mergers lead to slowly rotating , anisotropic remnants having predominantly boxy isophotes . mergers with a mass ratio of 3:1 and 4:1 , on the other hand , are fast isotropic rotators with disky isophotes . projection effects can explain the observed scatter in the kinematical and isophotal properties of elliptical galaxies ."
] | 636 | 636 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: this paper documents some of the dynamics observed when a gas is injected into a shallow pool of liquid . these dynamics are visible to the naked eye , but benefit from the high - frame rate and low exposure time offered by a high - speed camera . the high - speed video discussed in this paper is available in the accompanying http://ecommons.library.cornell.edu/bitstream/1813/11469/3/bird_dfd2008_mpeg1.mpg[movie ] , submitted to the 2008 american physical societies division of fluid dynamic s gallery of fluid motion . the experimental setup consists of a 7 gauge metal needle placed into a 5-millimeter deep pool of 10 cst silicon oil , such that part of the needle tip contacts the bottom of the container . similar regimes have been observed in other liquids , although the dynamics are less crisp . helium is pumped through the needle at a modest flowrate of 3 ml / s . the advantage of helium is that it is well - characterized , inert , and readily available ; we suspect that the dynamics shown in the movie are independent of the gas properties . the flow of helium into the silicon oil distorts the interface between the silicon oil and surrounding air . the precise dynamics of this deformation depend on the angle of needle , flowrate of the gas , and the depth and material properties of the liquid . in this study we have held the flowrate and pool depth constant while varying the angle of the needle , @xmath0 . at low needle angles ( @xmath1 ) , the air - silicon oil interface is in static equilibrium . once the angle approaches @xmath2 , ripples propagate across the surface . due to the size and speed of the ripples , we believe that they are capillary waves , that is waves that are regulated by surface tension . as the angle of the needle continues to increase , the amplitude of the capillary waves grows such that an oscillating bulge develops . at higher angles , the bulge becomes both larger and more focused , developing into periodic jets . once the jet aspect ratio of the jet becomes sufficiently small ( @xmath3 ) , the tip of the jet pinches off to form a spherical droplet . the droplets formed from the periodic jets float over the interface , similarly to how drops avoid coalescence over a vibrating fluid @xcite . it is worthwhile to note that the droplets often coalesce with each other before coalescing with the interface , implying that it is unlikely that natural surfactants are responsible for the floating behavior . as the angle of the needle increases , the height of the upward jets increase . at sufficient jet height ( @xmath4 ) , the jets break into two drops , leading to both a high parabolic arch and a lower droplet stream . between ( @xmath5 ) , the jet dynamics breakdown so that the droplet streams appear chaotic . large bubbles sporadically form at the fluid interface , often with jets emitting from the bubble surface . droplets are still emitted from the jets , but the resulting bubble streams are incoherent . we have found that injecting gas into shallow liquid can lead to a rich variety of interfacial dynamics . by sweeping the angle of the gas - injecting needle , we observe a smooth transition between static deformation , juggling and tumbling of droplet streams , and an incoherent mix of bubbles and jets , reminiscent of a daredevil shooting out of a canon . this combination of dynamics provides an aesthetically pleasing show of liquid acrobatics .
Abstract: | [
"we experiment with injecting a continuous stream of gas into a shallow liquid , similar to how one might blow into a straw placed at the bottom of a near - empty drink . by varying the angle of the straw ( here a metal needle ) , we observe a variety of dynamics , which we film using a high - speed camera . most noteworthy is an intermediate regime in which cyclical jets erupt from the air - liquid interface and breakup into air - born droplets . these droplets trace out a parabolic trajectory and bounce on the air - liquid interface before eventually coalescing . the shape of each jet , as well as the time between jets , is remarkably similar and leads to droplets with nearly identical trajectories . the following article accompanies the linked fluid dynamics video ( http://ecommons.library.cornell.edu/bitstream/1813/11469/3/bird_dfd2008_mpeg1.mpg[low resolution ] , http://ecommons.library.cornell.edu/bitstream/1813/11469/2/bird_dfd2008_mpeg2.mpg[high resolution ] ) submitted to the gallery of fluid motion in 2008 ."
] | 703 | 703 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: recent years have seen a rapid increase in the interest in finite quantum spin systems , also known as molecular magnets or nanomagnets @xcite . molecular magnets typically consist of clusters of interacting spins that are magnetically isolated from the other clusters in the molecular solid by nonmagnetic ligands . formally , molecular magnets are materials in which the ground state has nonzero total spin . here we generalize this definition to include all systems of largely isolated clusters of interacting quantum spins . these materials are interesting both as simple model systems for the study of quantum magnetism and because they have possible applications as nanoscale computer memory elements @xcite . many realizations of finite spin clusters with various ionic spins , ground state spins and geometries have been reported in the literature ; some recent examples with s=1/2 ions are given in table [ materials ] . theoretical results for the properties of finite s=1/2 quantum spin systems have appeared in several recent references , primarily in the context of experimental studies of specific materials . dimer results are reported in several studies of the s=1/2 spin dimer vo(hpo@xmath0)@xmath10.5h@xmath2o ; see for example johnson _ @xcite , tennant _ et al . _ @xcite and koo _ et al . theoretical properties of s=1/2 spin trimers have similarly been given in studies of candidate trimer materials ; see for example refs.@xcite . rather few general theoretical results have been reported for s=1/2 spin tetramers , since the results are more complicated and there are many more independent geometries and sets of superexchanges . specific cases of tetramers are considered by procissi _ et al . _ @xcite ( s=1/2 square tetramer ) , gros _ et al . _ @xcite and jensen _ et al . _ @xcite ( an unsymmetric s=1/2 tetrahedral model of cu@xmath2te@xmath2o@xmath3(br@xmath4cl@xmath5 ) ) , kortz _ et al . _ @xcite ( unsymmetric tetramer model of k@xmath6na[cu@xmath0k@xmath2(h@xmath2o)@xmath7(@xmath8-asw@xmath9o@xmath10)@xmath2]@xmath15.5h@xmath2o ) , and ciftja @xcite ( symmetric trimer with apical spin ) . more general reviews of quantum spin systems have been published by kahn @xcite ( thermodynamics ) and whangbo _ et al . _ @xcite ( local origins of magnetism , thermodynamics properties , and materials ) . studies of the dynamics of heisenberg spin clusters using a quasiclassical formalism have been reported in a series of papers by ameduri , efremov and klemm @xcite . waldmann @xcite has carried out calcuations of the inelastic neutron structure factor for cyclic heisenberg spin clusters which are quite similar to the results presented here . this increased level of interest in molecular magnets motivates more detailed theoretical investigation of the properties of finite quantum spin systems . for simple theoretical models such as the heisenberg model , clusters that consist of only a few interacting magnetic ions can be treated analytically , and closed - form results can be obtained for many physical observables . one especially interesting quantity is the inelastic neutron scattering structure factor , which is required for the interpretation of inelastic neutron scattering experiments . inelastic neutron scattering is very well suited to the investigation of magnetic interactions at interatomic scales , since the measured structure factor is sensitive to the local geometry and interactions of the magnetic ions . as this work is intended in part to facilitate future neutron scattering studies , the evaluation of this structure factor is one of our principal concerns .
Abstract: | [
"in this paper we report results for magnetic observables of finite spin clusters composed of s = 1/2 ions . we consider clusters of two , three and four spins in distinct spatial arrangements , with isotropic heisenberg interactions of various strengths between ion pairs . in addition to the complete set of energy eigenvalues and eigenvectors , specific heat and magnetic susceptibility , we also quote results for the single crystal and powder average inelastic neutron scattering structure factors . examples of the application of these results to experimental systems are also discussed ."
] | 664 | 664 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: we have recently completed a search of 56 unidentified mid - latitude egret @xmath0-ray sources for pulsations using the parkes telescope and the multibeam receiver . this survey covered @xmath1140 square degrees of sky at galactic latitudes @xmath2 and revealed six new pulsars , three of which are in binary systems . here we present initial timing results for the three binaries . the properties of the three new binaries are summarized in table 1 and their pulse profiles are shown in figure 2 . .newly discovered binaries [ cols="<,^,^,^,^,^,^ " , ] @xmath3 assuming a pulsar mass ( @xmath4 ) of 1.4m@xmath5 . + @xmath6 dm distance from the ne2001 electron density model of the galaxy ( cordes & lazio 2002 , astro - ph/0207156 ) . + psr j1614@xmath72230 is a recycled millisecond pulsar with a very low inferred magnetic field ( @xmath8 g ) . it has the highest minimum companion mass of the @xmath150 binary pulsars with spin periods lower than 8ms , suggesting a possible non - standard evolution . compared with the orbital period versus companion mass relationship of rappaport et al . 1995 ( mnras , 273 , 731 ) the orbital period of psr j1614@xmath72230 is short by a factor @xmath910 for its companion mass . the companion may be a cno white dwarf or a low - mass degenerate dwarf . the spin - down rate of psr j1614@xmath72230 gives an @xmath10 erg s@xmath11 , which is just barely consistent with the flux measured from the @xmath0-ray source in whose error box this pulsar was found . if the pulsar is the counterpart it would demand a very high @xmath0-ray efficiency , or a significantly closer distance than what is inferred from the dm . psr j1614@xmath72318 is likely partially recycled ( @xmath12 g ) . it has the lowest minimum companion mass of any binary pulsar with spin period between 10 and 100ms . the pulse profile is relatively wide at 1.4ghz ( @xmath130% of the pulse period at fwhm ) . at @xmath1350mhz the higher signal - to - noise ratio of the profile shows that there are wings on either side of the main pulse ( see figure 1 ) . it is possible that we are seeing emission from the core and cone of the beam . psr j1744@xmath73922 was also independently discovered by the parkes multibeam galactic plane survey ( a. lyne , private communication ) . it is possibly partially recycled ( @xmath13 g ) and is one of only @xmath116 binary pulsars with spin periods greater than 50ms ( of these it has the shortest orbital period and the third smallest minimum companion mass ) . it is difficult to detect at times , as it seems to shut off and turn on on timescales as short as a few tens of seconds ( see figure 2 ) . since its dm is relatively high , it is unlikely that scintillation is responsible for the many non - detections of the pulsar . psr j1744@xmath73922 has also been very difficult to detect at wavelengths other than @xmath11.4ghz . observations with the gbt have improved the detection rate of this strange pulsar . we have applied for exploratory observations of all three pulsars presented here with the 8-m gemini - south optical telescope in order to determine the magnitudes and colors of their binary companions and to see if they are consistent with being white dwarfs . these observations may lead to future spectroscopic observations of the companions , which could allow us to determine the neutron star masses and distances to the systems . with a clearer picture of the nature of the companion stars we would also be in a better position to comment on how these systems fit in with theories of binary evolution .
Abstract: | [
"we present three new binary pulsars discovered during a search for pulsations in 56 unidentified mid - latitude egret @xmath0-ray error boxes with the parkes multibeam receiver . timing observations of these sources is on - going with both the parkes and the green bank telescopes . we discuss the place of these new systems in the population of binary pulsars and suggest that they are all somewhat atypical systems . # 1_#1 _ # 1_#1 _ = # 1 1.25 in .125 in .25 in"
] | 732 | 732 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: nuclear spirals are known to be preponderant in active galaxies ( reagan & mulchaey 1999 ; martini et al . they have a variety of morphology , from the grand - design symmetric two - armed spirals to chaotic ones ( martini et al . the flocculent nuclear spirals are considered to be formed by the acoustic instability proposed by montenegro , yuan , & elmegreen ( 1998 ) , whereas the grand - design nuclear spirals are thought to be formed by the hydrodynamical instability caused by the gas inflow driven by the non - axisymmetric potentials ( englmaier & shlosman 2000 ) . it is well known that the response of gaseous disk to the imposed non - axisymmetric potentials depends not only on the potential shape of the model galaxy but also on the hydrodynamic properties of the gaseous disk ( ann & lee 2000 ; englmaier & shlosman 2000 ; maciejewski et al . however , the effects of smbhs on the gas flow inside the ilrs have not been studied much . here , we present some results of numerical experiments including smbh for the formation of nuclear spirals , based on smoothed particle hydrodynamics ( sph ) . we have assumed that a barred galaxy is made up of three stellar components ( bulge , disk , bar ) and two dark ones ( smbh , halo ) . we adopt simple analytic forms for the potential generated by each component . the properties of all the potential generating components are assumed to be invariant in time . we considered mass models which are thought to resemble early type galaxies ( @xmath0 sba ) by assuming the bulge - to - disk mass ratios as @xmath1 . we assumed a strong bar which has the fractional mass of 0.2 and the axial ratio ( a / b ) as 3 . the bar rotation period is @xmath2 years . we used isothermal assumption for the gas but we explored the effect of gas temperature by varying the sound speed of gas . we adopted @xmath3 and @xmath4 for the artificial viscosity coefficients . the self - gravity of gas was also included . fig . 1 shows snapshots of the evolution of the nuclear regions of gaseous disks at the evolution time of 20 bar rotations . the three models have the same mass distributions except for the central smbhs . the model m1 has no smbh , while the other two models ( m2 , m3 ) have a smbh whose mass is about @xmath5 of the total mass of the visible components ( disk , bulge and bar ) but they assumed different sound speeds in the gas ; 10 km / s for m2 and 15 km / s for m3 . the sound speed in the gas of m1 model is the same as that of the model m2 . as shown clearly in fig . 1 , the nuclear regions of the gaseous disk of m1 model evolves to leading spirals between the iilr and oilr , whereas those of m2 and m3 develop trailing spirals whose detailed shapes depend on the sound speeds in the gas . the cold gaseous disk assumed in the model m2 shows ring - like spirals , while the hot gaseous disk of the model m3 shows tightly wound spirals whose innermost parts reach close to the center . thus , it seems quite clear that the tightly wound trailing nuclear spirals can be developed in the hot interstellar medium when there is a smbh whose mass is large enough to remove the iilr . this is the reason why nuclear spirals are frequently observed in active galaxies . ann , h.b . , & lee , h.m . 2000 , jkas , 33 , 1 englmaier , p. , & shlosman , r.s . 2000 , , 528 , 677 maciejewski , w , teuben , p.j . , sparke , l.s . , & stone , j.m . 2002 , , 329 , 502 martini , p. , regan , m.w . , mulchaey , j.s . , & pogge , r.w . 2003 , , 146 , 353 montenegro , l. e. , yuan , c. , & elmegreen , b. g. 1999 , , 520 , 592 regan m.w . , & mulchaey j.s . , 1999 , , 117 , 2676
Abstract: | [
"we have performed sph simulations for the response of the gaseous disks to the imposed potentials including those from bars and smbhs . evolution of the nuclear regions of gaseous disks depends critically on the masses of smbhs as well as the sound speeds in the gas . # 1 1.25 in .125 in .25 in"
] | 832 | 832 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: regge calculus @xcite is used to re - examine a particular class of brill wave spacetimes @xcite investigated by miyama @xcite , and more recently , holz @xcite and alcubierre @xcite . in particular , we study the formation of apparent horizons within the simplicial initial data , and confirm recent findings regarding the appearance of such horizons @xcite . brill wave initial data was first constructed using regge calculus by dubal @xcite , although we show elsewhere @xcite that his procedure is unable to capture the full structure of complex axisymmetric initial data sets . by using an improved lattice ( which is described in full in ref . @xcite ) , we are able to accurately reproduce the continuum solution , and find apparent horizons in excellent agreement with recent two and three - dimensional calculations @xcite . we proceed as follows . in the next section , we briefly survey the approach taken by brill @xcite in the construction of gravitational wave initial data . in section [ sec : regge ] we describe the axisymmetric lattice used to construct brill waves using regge calculus . in section [ sec : trapped ] we describe the method used to find apparent horizons at a moment of time symmetry , and in section [ sec : horizons ] we investigate the appearance of apparent horizons in the brill wave space as the wave amplitude is increased . .mass estimates for the regge ( @xmath0 ) and continuum solutions ( @xmath1 ) . the mass is calculated from the decay of @xmath2 in the asymptotic region . we also show the results of previous calculations by holz @xcite and alcubierre @xcite , which are in excellent agreement . all our results were calculated on a @xmath3 grid . [ cols="^,^,^,^,^",options="header " , ] + using the technique outlined in section [ sec : trapped ] , we now search for apparent horizons in the brill wave initial data constructed in sections [ sec : continuum ] and [ sec : regge ] . we find that in both the regge and continuum solutions an apparent horizon first appears at a critical amplitude @xmath4 , which lies in the range @xmath5 $ ] . as the amplitude @xmath6 is increased above this critical value , two trapped surfaces are present , and these gradually separate . these results are in complete agreement with the recent calculations of alcubierre @xcite . figure [ fig : horizons]_a _ shows a projection of the trapped surfaces found for a wave amplitude of @xmath7 , calculated using both the continuum and regge solutions . there is a slight difference between the surfaces calculated using these two independent sets of initial data , but the discrepancy is found to reduce as the second power of the grid spacing . in figure [ fig : horizons]_b _ , we show the position @xmath8 of both trapped surfaces along the @xmath9-axis as a function of the brill wave amplitude . the quadratic fit to this data allows us to improve the estimate of the critical wave amplitude at which an apparent horizon first forms . we estimate that @xmath10 for the simplicial solution , and @xmath11 for the solution to the continuum equation . both solutions predict that the single horizon at @xmath12 passes through @xmath13 . the value of the critical amplitude @xmath4 , at which an apparent horizon first forms , differs from that obtained in an earlier calculation by some of us @xcite . the discrepancy in the earlier work was due to the relatively weak convergence criteria used for the trapped surface finder . qualitatively , the previous work agrees with both the present calculations and those of alcubierre @xcite . we have used regge calculus to confirm recent numerical findings regarding the formation of apparent horizons in a particular class of brill wave spacetimes , while demonstrating that regge calculus provides an alternative and competitive technique for use in numerical relativity . brill wave spacetimes provide a challenging test - bed for the future development of simplicial gravity . work is currently underway on the development of a simplicial trapped surface finder for regge calculus , as well as the time evolution of the initial data constructed here , in both @xmath14 and @xmath15-dimensions . we gratefully acknowledge support from a los alamos national laboratory ldrd grant . one of us ( apg ) acknowledges support from the sir james mcneill foundation at monash university , and from the center for nonlinear studies . # 1 , # 2 , # 3 , # 4 # 1 , * # 2 * , # 3 ( # 4 ) .
Abstract: | [
"we construct initial data for a particular class of brill wave metrics using regge calculus , and compare the results to a corresponding continuum solution , finding excellent agreement . we then search for trapped surfaces in both sets of initial data , and provide an independent verification of the existence of an apparent horizon once a critical gravitational wave amplitude is passed . our estimate of this critical value , using both the regge and continuum solutions , supports other recent findings . laur-98 - 5276"
] | 877 | 877 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: in our computations we adopt an initial helium content @xmath1 . we consider the complete sets of reactions for the pp - chain and cno tri - cycle , and the most important alpha - capture reactions for heavy elements up to mg . nuclear rates are taken from caughlan & fowler ( 1988 ) . the nuclear network is implicitly solved for all the considered h- and he - burning reactions , and without any additional assumption for nuclear equilibria . overshooting from stellar cores is applied according to the bressan et al . ( 1981 ) formalism . mass - loss from massive stars ( @xmath2 ) is described according to chiosi ( 1981 ) . stellar evolution is calculated throughout the nuclear h - burning phase up to the he - flash at the rgb tip for low - mass models , and throughout nuclear h- and he - burning phases up to the beginning of the tp - agb phase and carbon ignition for intermediate- and high - mass models , respectively . figure [ fig_hrd ] presents the evolutionary tracks in the h - r diagram . the appearance of short - lived loops is caused by the ignition of the 3-@xmath3 reaction during core and/or shell h - burning , leading to the first activation of the cno - cycle . in the case of low - mass stars ( @xmath4 ) a loop develops near the end of central h - burning ( @xmath5 ) , whereas for more massive stars ( @xmath6 ) a similar feature also occurs at the formation of the he - shell . as far as the critical stellar masses for non - degenerate nuclear ignition are concerned , we find that @xmath7 corresponds to the minimum initial mass for a star to avoid the he - flash , and @xmath8 the minimum initial mass for a star to avoid carbon deflagration . the first dredge - up is practically absent in all models . only for stars with @xmath9 a very small amount ( less than 0.003 @xmath0 ) of he is dredged - up to the surface . the second dredge - up is experienced by stars with @xmath10 , being quite efficient in models with @xmath11 . it turns out that the surface composition is enriched almost only in he ( reaching @xmath12 @xmath13 at increasing stellar mass ) and negligibly in cno elements ( @xmath14 @xmath15 in mass fraction ) . massive stars , with @xmath16 , do not show any trace of surface chemical pollution due to dredge - up episodes . only models calculated with mass - loss may expose nuclearly processed material to the surface . with the adopted prescription for mass - loss , stellar winds are never able to strip off h - exhausted layers in models with @xmath17 . in these cases , at most , the h - burning shell is eaten up , with consequent surface enrichment in he and small amounts of cno . for more massive models with @xmath18 , wind stripping is able to reach the co - enriched region left by convective he - burning . in these cases , the corresponding yields of c and o are considerable ( @xmath19 @xmath20 ) .
Abstract: | [
"we present new evolutionary models for zero - metallicity stars , covering a large range of initial masses ( from 0.8 to 100 @xmath0 ) . models are computed with overshooting from stellar cores and convective envelopes , and assuming mass - loss from the most massive stars . we discuss the main evolutionary features of these stars , and provide estimates of the amount of newly - synthesized elements dredged - up to the stellar surface , and possibly lost by stellar winds from the most massive stars . full details of these models will be given in marigo et al . ( 2000 , in preparation ) ."
] | 641 | 641 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: the radiation emitted by physical processes ongoing in active galaxies sculpt a spectral energy distribution ( sed ) that spreads on a wide range of the electromagnetic spectrum . multi - wavelength photometry is thus a rich source of information about the agn nature . one method to extract this information is through sed fitting , which consist in comparing the observed photometric data to a combination of physical models for agn components . it is customary to perform sed fitting using optimization methods as @xmath0-minimization , which defines the best fit as the combination of parameters which models the whole sed showing the minimal @xmath0 value . however , this method is statistically correct only under the assumption that the parameters are fully independent from each other and thus have a gaussian probability distribution . this assumption is a drawback of this method since the parameters describing agn physics are in most cases highly degenerated . to solve this issue we present agn__fitter _ _ , a bayesian sed fitting code for agn that allows an integral calculation of the posterior probability distributions of the model parameters taking into account degeneracies and correlations existing among them . agn__fitter _ _ samples the parameter space built by the agn models parameters using a markov chain monte carlo method . this consists in a random walk that is biased for regions of higher probability in the parameter space , making the code fast and efficient since no time is lost in non - interesting regions . built on the published code emcee ( ( * ? ? ? * ; * ? ? ? * ; * ? ? ? * foreman - mackey et al . 2011 ) ) our mcmc code increases its efficiency taking advantage of multiprocessing by parallel tempering , i.e. exploring the parameter space with several chains simultaneously . [ 0.96 ] the dimension of the parameter space sampled by agn__fitter _ _ is constructed in this first version by 10 parameters , which rule the modeling of four agn components : the accretion disk radiation , the nuclear hot dust emission and the radiation emitted by the host galaxy and the star burst regions . for the accretion disk radiation ( big blue bump ) we use the model by ( * ? ? ? * ; * ? ? ? * richards et al . ( 2006 ) ) , while the hot dust surrounding the disk is modeled by a continuous torus ( ( * ? ? ? * silva et al . 1994 ) ) . the contribution of the host galaxy to the full source radiation is modeled using ( * ? ? ? * ; * ? ? ? * ; * ? ? ? * bruzual & charlot ( 2003 ) ) templates , while the cold dust radiation produced in star burst regions is simulated using ( * ? ? ? * dale & helou ( 2002 ) ) templates . since many of these models cover equal regions of the spectrum it is important to take correlations into account . l0.48 agn__fitter _ _ constructs seds from existing physical models ( fig . 1 ) and calculate physical parameters that are interesting to agn physics , such as relevant integrated luminosities ( @xmath1 , @xmath2 , @xmath3 ) and parameters ruling the physics of the host galaxy , such as age , stellar mass @xmath4 and star formation rate ( sfr ) . moreover , agn__fitter _ _ provides both the marginalized and two - dimensional posterior density functions ( pdf ) of the parameters listed above . in this way degeneracies can not only be better visualized but also analyzed and treated ( fig.2 ) . finally , due to the code s bayesian methodology , the user is able to take advantage of prior constraints on the parameters distributions . in this way the information given by the likelihood function can be complemented , calculating robustly posterior probabilities of the parameters . agn__fitter _ _ is a robust statistical tool to model agn seds and to infer physical parameters from multiwavelength photometrical data . our code provides a vast statistical information about the inferred parameters allowing in this way an analysis of multiwavelength photometry cognizant of degeneracies and correlations , which is necessary for agn studies of general purpose .
Abstract: | [
"we present agn__fitter _ _ : a markov chain monte carlo algorithm developed to fit the spectral energy distributions ( seds ) of active galactic nuclei ( agn ) with different physical models of agn components . this code is well suited to determine in a robust way multiple parameters and their uncertainties , which quantify the physical processes responsible for the panchromatic nature of active galaxies and quasars . we describe the technicalities of the code and test its capabilities in the context of x - ray selected obscured agn using multiwavelength data from the xmm - cosmos survey ."
] | 824 | 824 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: we examined the vlba imaging and polarimetry survey ( vips , ( * ? ? ? * helmboldt et al . 2007 ) ) . it contains 1127 agn observations taken at 5 ghz with the very long baseline array ( vlba ) . the calibrated vlbi visibility data sets can be downloaded from the vips data collection index page . the original field of view of the interferometer was @xmath01.5 arcsec but the imaging was typically preformed only in the central area of 128 mas@xmath1128 mas . even though large structures were reported in the original publication and subsequent studies ( ( * ? ? ? * helmboldt et al . 2007 ) , ( * ? ? ? * tremblay et al . 2016 ) ) , we could find further objects in the full - field images with structures extending beyond the central area . the large sample size and the extended fields motivated us to image the sources and analyse the data in an automated way . the imaging and model fitting were performed through standard procedures using difmap ( ( * ? ? ? * shepherd et al . 1994 ) ) . we modeled the visibility data with a central elliptical gaussian component . in addition , extended structures were fitted with circular gaussians . the number of these components was determined by the signal - to - noise ratio ( snr ) in the residual map . we applied a 6-@xmath2 threshold for fitting a new component , as done in ( * ? ? ? * helmboldt et al . ( 2007 ) ) . thereafter , we calculated the separation of the circular components from the central elliptical gaussian . we marked the sources with at least one fitted component farther away than 50 mas from the centre as candidates for having large - scale structure within the full vlba field of view . we found 60 sources as candidates with extended structure among the 1127 vips sources . to check the quality of the candidate sample , we visually inspected all the wide - field images . we found that in a few cases the distant components are unreliable because of the low flux density of the fitted components . an increased snr threshold in the automated model - fitting procedure would eliminate these questionable cases . further quantitative classification of the sample is needed ( and planned ) . published information from the literature , analysis of archival data , and eventually new targeted observations would be necessary to reveal the true nature of these objects , on a case - by - case basis . these sources show great diversity in morphology and brightness . the large , typically @xmath00.11 kpc structures could most probably be extended jet structures . however , the possibility of dual radio agn or gravitationally lensed radio sources should also be investigated . as an illustration , we present an example from the candidate sample ( fig.[fig1 ] ) . 200 milli - arcseconds ( mas ) south of the central component . follow - up multi - frequency observations could be useful to decide if this is a kpc - separation dual radio agn , a gravitationally lensed background source with two images , or an agn core plus a hot spot embedded in an extended lobe that is resolved out with the vlba . the area originally imaged in vips is enclosed by the dashed line.,width=336 ] this work was supported by the hungarian national research , development and innovation office ( otka nn110333 ) . kr thanks the nkp-16 - 2 new national excellence program of the ministry of human capacities for support .
Abstract: | [
"the observation and imaging of hundreds or thousands of radio sources with the technique of very long baseline interferometry ( vlbi ) is a computationally intensive task . however , these surveys allow us to conduct statistical investigations of large source samples , and also to discover new phenomena or types of objects . the field of view of these high - resolution vlbi imaging observations is typically a few arcseconds at cm wavelengths . for practical reasons , often a much smaller fraction of the field , the central region is imaged only . with an automated process we imaged the @xmath01.5-arcsec radius fields around more than 1000 radio sources , and found a variety of extended radio structures . some of them are yet unknown in the literature ."
] | 713 | 713 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: the star formation history ( sfh ) of stellar populations ( e.g. galaxies and clusters ) may be derived using the synthetic cmd method ( scm ) based on the interpolation in mass and age of the stellar evolutionary models ( sem ) . to perform systematic studies and comparisons of the sfh of galaxies , the sems should have : _ i _ ) a dense grid over a large masse range ( up to 100 m@xmath0 ) to cover the entire age of the universe ; _ ii _ ) a homogeneous input physics ; _ iii _ ) a dense grid in metallicity ( z ) to cover the large range in metallicity of the stellar populations . at present , only a few sems datasets satisfy two of the previous points : padova94 ( @xcite ) dataset is one of them , but its grid in metallicity is too coarse , particularly in the z range 0.0004 - 0.004 , that is the most commonly used . to compensate for this limitation , we have interpolated in this metallicity range the padova94 models . in this work , we discuss ( section 2 ) our cares and prescriptions to obtain the interpolated tracks for z=0.001 ( fig . the comparison between our results and ( * ? ? ? * hereafter g00 ) models , of the same metallicity , are shown in section 3 , in order to emphasize the reliability of the interpolation . the interpolation in metallicity require special care to avoid spurious features in the resulting grid . our procedure goes through three steps : 1 . the subdivision of the tracks in specific evolutionary phases with : _ i _ ) the same internal burning processes ; _ ii _ ) comparable lifetimes ; _ iii _ ) similar behaviors on the hrd . + the subphases differ for the low , intermediate or high masses because of the different structures on the hrd . interpolations are performed at constant fractionary age within each subphase . we have performed several tests within padova94 sets to get the reliable interpolation method . we have found that an average of linear and logarithmic factor in z gives us the best result . the age has been linearly interpolated . we choose the transition masses for the selected metal content taking into account the trend of the transition masses over all the metallicity range . g00 models are similar to padova94 models , although some differences are present because of different input physics . we test our interpolated tracks by comparing them with g00 models at z=0.001 : 1 . the @xmath1 $ ] of the _ h - burning phase _ is less than 2% for m @xmath2 m@xmath0 . and smaller than 15% for m @xmath3 m@xmath0 . the latter discrepancy reflects the different definition of the overshooting parameter in the mass range 1 - 1.4 m@xmath0 . 2 . the @xmath4 of the _ he - burning phase _ is less than 15% for m @xmath5 m@xmath0 and smaller than 7% for m @xmath6 m@xmath0 . for m=1.7 m@xmath0 the he - burning lifetime of our model is two times larger than that of g00 . this is because in our set the m=1.7 m@xmath0 is adopted to be below the transition mass , while in g00 models it is close to the transition mass . taking into account the differences in the input physics , we find a good general agreement by comparing the interpolated tracks with the g00 models ( e.g. the lifetime of the major phases are reasonably well evaluated ) although some difference are present especially in the extention and luminosity of the blue loops . the results showed here refers to a specific choice of z. the same interpolation algorithm has been succesfully applied to other interpolated dataset ( z=0.002,0.003 ) and for other metallicity range ( z=0.004 - 0.008 ) . bressan a. , fagotto f. , bertelli g. , chiosi c. , 1993 , a&as , 100 , 647 fagotto f. , bressan a. , bertelli g. , chiosi c. , 1994 , a&as , 105 , 29 fagotto f. , bressan a. , bertelli g. , chiosi c. , 1994 , a&as , 104 , 365 girardi l. , bressan a. , bertelli g. , chiosi c. , 2000 , a&as , 141 , 371
Abstract: | [
"in this proceeding we present the procedure that we have adopted to obtain a dataset of padova94 tracks ( @xcite ) interpolated in metallicity . the procedure requires special care to avoid spurious features in the resulting grid , thus we have subdivided tracks in evolutionary phases , we have chosen the suitable interpolation method and the transition masses . finally , we have compared our interpolated dataset with a similar models , @xcite , obtaining a general good agreement ."
] | 831 | 831 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: we have observed the pulsar vela with a range of australian telescopes . using the long baseline array ( lba ) we have measured the parallax of pulsar , and thus the distance . using the australia telescope compact array ( atca ) we have found the radio pulsar wind nebula ( pwn ) that surrounds the x - ray pwn . using the university of tasmania s dedicated pulsar monitoring telescope in hobart we have detected the core interaction in the spin up of the pulsar in the glitch of 2000 . the pulsar monitoring telescope at hobart is a fourteen meter radio telescope dedicated to timing the vela pulsar . it collects three frequencies ( 635 , 990 , 1340-mhz ) , and the central one is collected unfolded for high resolution timing analysis ( @xcite ) . the ` fast component ' observed , which was fitted with a decay time 1.2 minutes , has been reanalysed with a more realistic model . we marginally detect the core interaction in the spin up ( @xcite ) . the atca has been used to map the radio pwn at 21 cm , 13 cm , 6 cm and 3 cm . because we used compact configurations with better sensitivity to low surface brightness objects we are able to map the whole nebula , unlike previous observations ( @xcite ) . we have used a single baseline from the lba to measure the on sky motion of the vela pulsar compared with the extra galactic source vela - g . we have measured the proper motion and parallax of the vela pulsar to an unprecedented accuracy ( @xmath0 @xmath1 , @xmath2 mas ) , and have been able to convert these back to the space velocity and position angle of the pulsar in its local environment with greater precision that previously possible ( @xmath3 @xmath4at @xmath5 ) , because of the unambiguity in the radio reference frame . we have found an arithmetic error in @xcite and , once corrected , their results agree with ours ( caraveo , personal comms ) . we have funding for a coherently dedispersed 30mhz backend for the 635mhz if on the pulsar timing telescope . this should allow us an increase in sensitivity of an order of magnitude over the previous observations . we plan to observe at the atca the radio nebula at higher frequencies to find the turn over frequency , and model the emission from the x - rays down to the radio frequencies . we are observing at the vla to get sensitive rapid observations to measure changes associated with the recently discovered x - ray outer jet ( @xcite ) . the limitation in the accuracy of the vlbi observation is the solar motion parameters , and we can not improve on this . nevertheless we are planning to use vela as a demonstration source in a baseband e - vlbi experiment .
Abstract: | [
"of all pulsars known vela has been one of the most productive in terms in understanding pulsars and their characteristics . we present the latest results derived from australian telescopes . these include a more accurate pulsar distance , a more precise pulsar local space velocity , a new model of the spin up and the association of a radio nebula with the x - ray pulsar wind nebula . # 1_#1 _ # 1_#1 _ = # 1 1.25 in .125 in .25 in"
] | 585 | 585 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: what has been available to eso up to now are efficiency curves provided by the vimos consortium that are averaged over the four quadrants and were determined with laboratory measurements , not by observing standard stars . prompted by user requests to have separate efficiency estimates for each quadrant , two spectrophotometric standard stars were observed in 2006 : hiltner 600 for all filters , and ltt7379 for the u and b band . these observations were performed with the broadest possible slit ( 5@xmath0 ) and the grisms lr - blue ( for u , b , and v ) and lr - red ( for r , i , and z ) . under the assumption that the total star - light is contained in the slit , the efficiency curve is derived from the measured flux . the required input consists of the tabulated standard star flux , the extinction curve , and the grism transmission as provided by the vimos consortium . the resulting curves are shown in fig . [ smieske : fig1 ] . they are also available from the public vimos web - pages . there is good agreement between the newly derived efficiency estimates and those from the consortium . the substantial sensitivity drop in quadrant 3 for the u - band is found independently for both ltt 7379 and hiltner 600 ( note that the measurement for hiltner 600 was not used for the efficiency estimate in the u - band since it suffered from flux loss in all four quadrants , due to a slight misalignment of the standard within the slit ) . since the u - band photometric zero - points for q3 do not show such a strong drop , a centring problem due to instrument flexure is a possible reason for this lack of measured flux . in addition , the consortium estimate of the grism transmission in q3 for l@xmath13800 may be too high . we suggest that the efficiency estimates especially in the u - band be always re - scaled to the ( integrated ) photometric zero - points . in addition to the total instrument+telescope efficiency estimates , we used the continuum lamp screen flats taken with and without inserted filter to measure the filter transmissions for each quadrant . the results are shown in fig . [ smieske : fig3 ] and compared with the consortium estimates . there is very good agreement for the v , r , i , and z filters . for the u - band , the consortium estimates are about 20% above those derived from the screen flats . also for the b - band , the consortium estimates are about 5 - 10% higher . unlike in the consortium filter transmission curves from fig . [ smieske : fig3 ] , we do _ not _ detect a red leak of the u - band filter around 4200 . only in q4 , there is a very minor leak at about 4850 ( see fig . [ smieske : fig2 ] ) . the measured telescope+instrument efficiency curves for the vimos broad band filters agree very well with the consortium estimates . a discrepancy in the u - band is observed for one quadrant , possibly due to flexure and low grism transmission at short wavelengthes . the filter transmissions also agree very well , except for the b and especially u - band , where the newly measured transmission is about 20% lower .
Abstract: | [
"vimos is a wide - field imager and spectrograph mounted on ut3 at the vlt , whose fov consists of four 7x8 quadrants . here we present the measurements of total transmission profiles i.e. the throughput of telescope + instrument for the broad band filters u , b , v , r , i , and z for each of its four quadrants . those measurements can also be downloaded from the public vimos web - page . the transmission profiles are compared with previous estimates from the vimos consortium ."
] | 680 | 680 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: it has been suggested that the most massive planets in a planetary system can be formed by a process of gas collapse , independently of metallicity , whilst the lighter components would have formed via core accretion . this can lead to a situation in which massive planets that have originated relatively far away from the inner system , migrate inwards into it ( see * ? ? ? * and contribution by font - ribera et al . in this same volume ) . in this process , these more massive planets with larger semi - major axis , cross the gas disc centred around the central sun . when going through this dissipative process , the planets lose kinetic energy because of the friction with the gas . as a consequence , the inner disc is heated up and the semi - major axis of the planet shrinks . after some passages , the planet is trapped in the disc with a residual eccentricity . we propose this scenario as a plausible way of explaining the existence of massive planets distributed around a sun with non - zero eccentricities . we give results based on high - accurate dynamical simulations about the distribution of the orbital elements of the trapped objects in the disc . we find that the massive planets are typically captured after some @xmath0 yrs and the final eccentricity is non - negligible ( @xmath1 ) . we have recently developed an integrator bhint specialised for dynamical processes in the vicinity of a very massive particle , which relies in the assumption that the very massive particle dominates the motion of the smaller ones @xcite . for this new mechanism , we retain the hermite scheme as a basis . the bottleneck is , of course , the number of particles to be used . nonetheless , we resort to special - purpose hardware , the grape , a card specially developed to integrate the calculation of newtonian gravitational forces . the peak performance of one of these cards is of 130 gflop , roughly equivalent to 100 single pcs , which makes possible long simulations with a realistic particle number . we set initially a disc made out of @xmath2 small particles which is `` hosting '' a sun in the centre and follows a simple @xmath3 profile . the integrated mass is of some 5 jupiters and the radius of some @xmath4 au . the thickness of the disc is of about the diameter of the central sun and has a gap around the central sun which extends @xmath5 au . the mass of the central sun is @xmath6 . the mass forming the disc are all single - mass . the massive planet , a massive particle of 5 jupiters is set in an orbit such that the initial eccentricity with the sun is of @xmath7 . initially , the particle is 100 au away from the sun and the inclination angle is @xmath8 degrees . the system ( disc plus interloper ) is integrated until the interloper is trapped by the disc . in the figure we show the evolution of the orbital parameters . whilst we can not discuss them in detail because of the publication limits , we note that after some @xmath9 yrs the inclination has almost not changed as compared to its initial value . then , after a short time of @xmath10 yrs elapses , it abruptly decays from almost 80 degrees to a very small number , to be finally trapped in the disc after @xmath11 yrs . the energy , whilst it decays from the initial high value of 0.95 , is of @xmath1 when the massive planet is totally trapped in the disc , within a final semi - major axis which is well within the range of expectation . an extended and detailed scrutiny of the parameter space of this capture process we propose will be soon published elsewhere @xcite . the adressing of this scenario has direct bearing on our understanding of planetary dynamics and migration mechanisms .
Abstract: | [
"we analyse the potential migration of massive planets forming far away from an inner planetary system . for this , we follow the dynamical evolution of the orbital elements of a massive planet undergoing a dissipative process with a gas disc centred around the central sun . we use a new method for post - newtonian , high - precision integration of planetary systems containing a central sun by splitting the forces on a particle between a dominant central force and additional perturbations . in this treatment , which allows us to integrate with a very high - accuracy close encounters , all gravitational forces are integrated directly , without resorting to any simplifying approach . after traversing the disc a number of times , the planet is finally trapped into the disc with a non - negligible eccentricity"
] | 776 | 776 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: in the relativistic jets of agns or grbs , the observed flux is related to their intrinsic flux by @xmath0 , where @xmath1 is doppler factor , @xmath2 and @xmath3 are the observed and intrinsic flux respectively , and @xmath4 is the spectral index ( ( * ? ? ? * blandford & knigl 1979 ) ) . if @xmath1 is greater than 1 , then the observed flux will be enhanced , which is called doppler boosting effect . on the other hand , if @xmath5 is less than 1 , the observed flux is attenuated , which is named to doppler deboosting effect . the doppler factor of a jet can be described by the following equation , @xmath6 where @xmath7 is the velocity , @xmath8 is the lorentz factor , and @xmath9 is the viewing angle . for a counter relativistic jet where @xmath10 , the doppler factor @xmath1 is always less than 1 , which can easily be derived from equation [ eqn1 ] . so a counter jet is always doppler deboosted . for a forward relativistic jet , the situation is more complex . provided that the viewing angle of jet @xmath11 ( when @xmath12 , @xmath1 is always greater that 1 ) , the doppler factor can be greater than 1 as well as less than 1 ( see figure [ fig01 ] for detail ) . therefore , both doppler boosting and deboosting effects could happen in forward jets . in many radio loud agns , the large scale jets share some common features in their profiles . firstly , there are compact and bright cores in the center of jets . secondly , adjacent to the cores , the flux of the jets drops down very quickly , even form some gaps where the jets are undetectable . thirdly , the jets will be re - brightened in the outer region . recently , the swift found some interesting properties in grbs . five grbs x - ray light curves are characterized by a rapid fall - off for first few hundred seconds , followed by a less rapid decline lasting several hours . the light curves also show discontinuity ( ( * ? ? ? * tagliaferri et al . ( 2005 ) ) ) . @xcite found that there were bright x - ray flares in grb afterglows . * stage i : the jets are accelerating and boosting , which relates to the bright cores of agns and the bursts of grbs . the initial acceleration of relativistic jets has been detected in 3c 273 by @xcite and modeled by @xcite . in this stage , @xmath8 is usually less than a few tens , and @xmath1 increase very quickly . * stage ii : the jets are accelerating but deboosting . as the acceleration continues , @xmath8 will be very large ( @xmath13 ) . therefore , the jets will enter into the deboosting area , i.e. @xmath14 . in this stage , the observed flux of the jets decreases very quickly , and often forms the gaps between inner and outer jets in agns and the rapid decays and discontinuous light curves in grbs . * stage iii : the jets are decelerating and boosting . the acceleration , however , wo nt last forever because of radiation loss and the interaction between the jets and the surrounding medium . thus , the jets will decelerate and their @xmath1 will increase again . consequently , the doppler boosted jets will appear again in the profiles of agns or in the light curves of grbs . * stage iv : the jets are decelerating and deboosting . finally , due to the same reasons in stage iii , the jets will gradually disappear . blandford , r.d . , knigl arieh , 1979 , _ apj _ , 232 , 34 burrows , d.n . , romana , p. , falcone , a. et al . , 2005 , _ science _ , 309 , 1833b krichbaum , t.p . , graham , d.a . , witzel , a. et al . , 2001 , _ particles and fields in radio galaxies , asp conference series _ tagliaferri , g. , goad , m. , ghincarini , g. et al . , 2005 , _ nature _ , 436 , 985 t zhou , j.f . , zheng , c. , li , t.p . et al . , 2004 , _ apj _ , 616l , 95z
Abstract: | [
"it is widely accepted that the doppler deboosting effects exist in counter relativistic jets . however , people often neglect another important fact that both doppler boosting and deboosting effects could happen in forward relativistic jets . such effects might be used to explain some strange phenomena , such as the invisible gaps between the inner and outer jets of agns , and the rapid initial decays and re - brightening bumps in the light curves of grbs ."
] | 850 | 850 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: imaging of extrasolar planets is a very challenging goal because of the very large luminosity contrast ( of the order 10@xmath1 for young giant planets and of the order of 10@xmath2 - 10@xmath3 for old giant and rocky planets ) and the small angular separation ( few tenths of arcsec for a planet at @xmath410 au around a star at some tens of pc ) between the host star and the companion objects . however , a number of different project are either now running ( e.g. project 1640 at the 5 m palomar telescope - see ( * ? ? ? * crepp et al . 2011 ) ) or are going to begin like the gemini planet imager ( gpi ) at the gemini south telescope ( ( * ? ? ? * macintosh et al . 2006 ) ) or sphere at the eso very large telescope ( ( * ? ? ? * beuzit et al . 2006 ) ) . this last instrument , in particular , includes three scientific channels that are a differential imager and dual band polarimeter called irdis operating in the near infrared between the y and the ks band ( ( * ? ? ? * dohlen et al . 2008 ) ) , a polarimeter called zimpol that will look for old planets at visible wavelengths ( ) and an integral field spectrograph ( ifs ) operating in the near infrared between the y and the h band ( ( * ? ? ? * claudi et al . 2008 ) ) . in the next paragraphs we will present the results of the laboratory tests on the ifs . tests on the ifs instrument were held in january and february 2013 at the _ institut de planetologie et dastrophysique de grenoble _ ( ipag ) facility with the aim to validate functionality of the science and calibration templates and to preliminary estimate the performances of the instrument . the tests were performed both in the yj ( [email protected] micron ) and in yh ( [email protected] micron ) mode using the appropriate combination of lyot coronagraph and apodized mask . data were then reduced exploiting the data reduction and handling ( drh ) software that allows to perform all the required calibrations and the speckle subtraction procedure through the spectral deconvolution ( sd ) method ( ( * ? ? ? * sparks & ford 2002 ) ) . a further speckle suppression can be obtained applying angular differential imaging ( adi ) ( ( * ? ? ? * marois et al . 2006 ) ) . given that we do can not perform any rotation of the field of view during our tests , we can just perform a simulation of the method so that our results have to be regarded as just an estimation of the contrast that we will be able to get . in figure [ fig2 ] we display the 5@xmath6 contrast plot that we can get for the ifs operating both in the yj - mode ( left panel ) and in the yh - mode ( right panel ) . a contrast better than 10@xmath1 can be obtained for both the modes appropriately combining sd and adi . to further confirm this results we add a number of simulated planets to the raw data at different separations and with luminosity contrast of 10@xmath7 and 10@xmath1 and reduced these data following the same procedure . all simulated planets are visible with a s / n greater than 5 .
Abstract: | [
"until now , just a few extrasolar planets ( 30 out of 860 ) have been found through the direct imaging method . this number should greatly improve when the next generation of high contrast instruments like gemini planet imager ( gpi ) at gemini south telescope or sphere at vlt will became operative at the end of this year . in particular , the integral field spectrograph ( ifs ) , one of the sphere subsystems , should allow a first characterization of the spectral type of the found extrasolar planets . here we present the results of the last performance tests that we have done on the ifs instrument at the institut de planetologie et dastrophysique de grenoble ( ipag ) in condition as similar as possible to the ones that we will find at the telescope . we have found that we should be able to reach contrast down to 5x10@xmath0 and make astrometry at sub - mas level with the instrument in the actual conditions . a number of critical issues have been identified . the resolution of these problems could allow to further improve the performance of the instrument ."
] | 686 | 686 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: in this configuration , the brunt - visl frequency is simply proportional to the radial distance . many mathematical results are known ( friedlander & siegmann 1982 ) concerning the shape of critical surfaces and characteristics of the governing mixed type operator . we confirm all these results by calculating the orbits of characteristics which propagate in the hyperbolic domain . in particular , we find that characteristics can be focused along attractors leading to associated singular velocity fields ( dintrans et al . we study , using the anelastic approximation , the low - frequency oscillations of a typical @xmath0-doradus star . hence , we show that dealing with rotation by the means of a second - order perturbative theory is not correct for rotation periods less than 3 days . using the same geometric formalism as above ( i.e. calculations of orbits of characteristics ) allows us to compute the frequencies of oscillations in the rapid rotation rgime ( rotation periods @xmath1 1 day ) . we find again that wave attractors are a common feature of rapidly rotating fluids and conclude that they are promising features for the transport of angular momentum and chemicals in the radiative zone of rotating stars ( dintrans & rieutord , 1999 ) .
Abstract: | [
"we present numerical simulations of gravito - inertial waves propagating in radiative zones of rapidly rotating stars . a first model , using the boussinesq approximation , allows us to study the oscillations of a quasi - incompressible stratified fluid embedded in a rapidly rotating sphere or spherical shell . in a second step , we investigate the case of a @xmath0 doradus - type star using the anelastic approximation . some fascinating features of rapidly rotating fluids , such as wave attractors , appear in both cases . # 1_#1 _ # 1_#1 _ = # 1 1.25 in .125 in .25 in"
] | 301 | 301 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: monitoring known radial velocity ( rv ) planets at predicted transit times , particularly those planets in relatively eccentric orbits , presents an avenue through which to investigate the mass - radius relationship of exoplanets into unexplored regions of period / periastron space beyond ( kane & von braun 2008 , 2009 ) . here we describe techniques for refining ephemerides and performing follow - up observations ( kane et al . these methods are used by the transit ephemeris refinement and monitoring survey ( terms ) . the transit window as described here is defined as a specific time period during which a complete transit ( including ingress and egress ) could occur for a specified planet . the size of a transit window will increase with time due to the uncertainties in the fit parameters , and thus follow - up of the transit window as soon as possible after discovery is optimal . figure 1 ( left panel ) shows the size of the transit window for a sample of 245 exoplanets . the transit windows of the short - period planets tend to be significantly smaller than those of long - period planets since , at the time of discovery , many more orbits have been monitored to provide a robust estimate of the orbital period . terms chooses targets that have small transit windows , medium - long periods , and a relatively high probability of transiting the host star . [ cols="^,^ " , ] the transit ephemeris for a particular planet can often be significantly improved with the addition of a handful of high - precision rv data . for example , the planet orbiting the star hd 231701 ( fischer et al . 2007 ) has a current transit window of @xmath082 days based upon the discovery data . the addition of four subsequent measurements as shown in figure 1 ( right panel ) would improve both the precision of the period and time of periastron passage , resulting in a reduction of the transit window to 3.7 days - a factor of almost 25 ! through selective observations at optimal times , we produce viable targets for photometric follow - up . a considerable number of high transit probability targets are difficult to monitor adequately during their transit windows because the uncertainties in the predicted transit mid - points are too high . the acquisition of a handful of new rv measurements at carefully optimised times can reduce the size of a transit window by an order of magnitude . this is described in more detail by kane et al . ( 2009 ) . figure 2 presents data acquired with the t10 0.8 m automated photoelectric telescope ( apt ) during a predicted transit time of hd 114762b . the transit window was refined to less than a day using lick rv data , and the transit of this planet was subsequently ruled out . the observations from this survey will lead to improved exoplanet orbital parameters and ephemerides even without an eventual transit detection . the results from terms will provide a complementary dataset to the fainter magnitude range of the _ kepler _ mission , expected to discover many intermediate to long - period transiting planets .
Abstract: | [
"transiting planet discoveries have largely been restricted to the short - period or low - periastron distance regimes due to the bias inherent in the geometric transit probability . through the refinement of planetary orbital parameters , and hence reducing the size of transit windows , long - period planets become feasible targets for photometric follow - up . here we describe the terms project that is monitoring these host stars at predicted transit times ."
] | 638 | 638 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: the discovery of type1-like broad emission lines in the polarized spectrum of the type2 seyfert galaxy ngc1068 @xcite led to the foundation of the so - called unification model ( um ) of agns ( e.g. * ? ? ? * ) in which the orientation of a dusty torus plays a crucial role in the spectroscopic classification of the agn for a given observer . while this um is now well accepted for the lower luminosity agns , a key question is whether it applies to higher luminosity objects like quasars since the presence of the dusty torus may be affected by the higher radiation flux . in order to get some insights into the quasar inner structure , we investigate the possible existence of a correlation between the direction of the linear optical polarization ( @xmath0 ) and the orientation of the major axis ( @xmath1 ) of the host galaxy / extended emission surrounding rq and rl quasars . the sample used in our study is made of type1 and type2 rq / rl quasars for which high resolution visible / near - ir images are available and with optical polarization data reported in the literature . we determined the @xmath1 for the objects with missing measurements by using the mcs deconvolution method @xcite . from this compilation , we selected a sub - sample of objects for which we have relevant and accurate data and then computed the acute angle @xmath2 between the directions defined by the @xmath1 and @xmath0 angles . further details about the quasar sample and the determination of the @xmath1 are available in @xcite . the behavior of the angle @xmath2 as a function of the observation wavelength @xmath3 as measured in the quasar rest - frame is illustrated in the left panel of fig . 1 . from the analysis of the data plotted , we conclude that while no particular behavior is noted at redder wavelengths ( @xmath3 @xmath4 ) , a clear dichotomy appears in the uv / blue domain where the type1 quasars tend to have their ee preferentially aligned ( @xmath5 ) with the polarization direction , these two axes being mainly orthogonal ( @xmath6 ) in the type2 objects . moreover , the observed alignment effect seems to be independent of the radio - loudness . in the case of the type2 quasars , this behavior is known as the _ alignment effect _ reported by @xcite and @xcite where the extended uv / blue emission resolved in images is interpreted as an electron / dust polar region , scattering off the nuclear light and explaining the anti - alignment . in type1 quasars , the alignment can be explained by assuming a two - component scattering model ( see fig . 1 ) , similar to the one proposed for the seyfert galaxies by @xcite . in this scenario , an equatorial scattering region located inside the dusty torus produces a polarization aligned with the torus symmetry axis . the resulting polarization , the sum of the polar and equatorial contributions , is dominated by the equatorial component because of the higher symmetry of the polar region at smaller viewing angles ( see * ? ? ? * ) . antonucci , r. , & miller , j. 1985 , , 93 , 785 antonucci , r. 1993 , , 31 , 473 borguet , b. , hutsemkers , d. , letawe , g. , et al . 2008 , , 478 , 321 cimatti , a. , di serego - alighieri , s. , fosbury , r. , et al . 1993 , , 264 , 421 magain , p. , courbin , f. , & sohy , s. 1998 , , 449 , 472 smith , j.e . , robinson , a. , alexander , d. , et al . 2004 , , 350 , 140 zakamska n. , strauss , m. , krolik , j. , et al . 2006 , , 132 , 1496
Abstract: | [
"we investigate correlations between the direction of the optical linear polarization and the orientation of the host galaxy / extended emission for type1 and type2 radio - loud and radio - quiet quasars . we have used high resolution hubble space telescope data and a deconvolution process to obtain a good determination of the host galaxy / extended emission ( ee ) position angle . with these new measurements and a compilation of data from the literature , we find a significant correlation , different for type1 and type2 objects , between the linear polarization position angle and the orientation of the ee , suggesting scattering by an extended uv / blue region in both types of objects . our observations support the extension of the unification model to the higher luminosity agns like the quasars , assuming a two component scattering model ."
] | 762 | 762 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: it is widely accepted that cold and luminous submillimeter ( submm ) galaxies ( smgs ) are dominant contributors to the star formation history of the universe at redshifts @xmath0 @xcite . on the other hand , the host galaxies of long - duration gamma - ray bursts ( grbs , originating in the collapses of very massive stars , e.g. * ? ? ? * ) are found to be subluminous @xcite and low - mass @xcite . four of them ( grbs 980703 , 000210 , 000418 and 010222 ) have been firmly detected in submm and/or radio ( @xcite @xcite ; @xcite @xcite ; @xcite @xcite ) . in this paper we discuss the possibility that these submm - bright grb hosts may represent the hotter counterparts of smgs . for details see @xcite and @xcite . in order to model the spectral energy distributions ( seds ) of grb hosts we used the grasil software @xcite . it is a numerical code that calculates the spectrum of a galaxy by means of a radiative transfer method , applied to photons produced by a stellar population , and reprocessed by dust . in figure [ fig : t_l ] we compare the total infrared luminosities and dust temperatures of grb hosts ( derived from the sed fits ) with well - studied galaxies both local and at high-@xmath1 . it is apparent that grb hosts are hotter than smgs with the same luminosity . this gives a hint that grb events may pinpoint a population of ultraluminous infrared galaxies ( ulirgs ) at high redshifts with dust hotter than in typical smgs . the search for such galaxies is important because they likely contribute to the star formation history at the same level as smgs . we note that the majority of the galaxies shown in figure [ fig : t_l ] also have higher dust temperatures compared to smgs . however , all of them are local galaxies , so can not be considered as counterparts of high - redshift smgs and their submm emission has been detected only because of their proximity . grb hosts may be consistent with a population of optically faint radio galaxies ( ofrgs ) having similar infrared luminosities and ( likely ) temperatures . although the majority of ofrgs lie at @xmath2 @xcite , some of them are within the redshift range of the grb hosts discussed here ( ) . ofrgs have been suggested to be hotter counterparts of smgs @xcite , so the same may be true for grb hosts .
Abstract: | [
"using detailed spectral energy distribution fits we present evidence that submillimeter- and radio - bright gamma - ray burst host galaxies are hotter counterparts to submillimeter galaxies . this hypothesis makes them of special interest since hotter submm galaxies are difficult to find and are believed to contribute significantly to the star formation history of the universe ."
] | 522 | 522 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: the grb050730 afterglow was observed 4.0 hours after the trigger . we find seven main absorption systems at z=3.968 , 3.564 , 2.2536 , 2.2526 , 2.2618 , 1.7729 and 1.7723 the grb050922c afterglow was observed 3.5 hours after the trigger . we find four main absorption systems at z=2.199 , 2.077 , 2.008 and 1.9985 . the grb060418 afterglow was observed 10 minutes after the trigger . we find four main absorption systems at z=1.489 , 1.106 , 0.655 and 0.602 . the resolution of all spectra is r 40,000 ( 7.5 km / s in the observer frame ) . data sets were reduced using uves pipeline for midas . all afterglows are clearly detected in the range 3300 - 10000 . fine structure lines for cii , oi , feii and siii have been identified in all the grbs . such lines convey information on the temperature and electron density of the absorbing medium , provided that they are excited by collisional processes ( j. n. bahcall , r. a. wolf et al . _ apj _ , 152 , 701 , 1968 ) . to constrain these parameters we need to estimate the fine structure column densities for two different ions and compare them . for grb050730 , two out of five components show fine structure lines ( fig . [ ciietc ] ) . reliable values for temperature and electron density are t a few @xmath1 k and @xmath2 @xmath3 ( second component ; the components are numbered according to decreasing z ) and @xmath4 @xmath3 ( third component ) . the other components do not show fine structure features : this is an indication that they refer to a clumpy environment . metallicity in grbs can be measured comparing the column densities of heavy elements to that obtained for hydrogen by fitting the ly@xmath5 , @xmath6 and @xmath7 profiles . both for grb050730 and grb050922c , we find metallicities between @xmath8 and @xmath9 with respect to the solar values . since metals tend to form dust , that then does not contribute to the absorption lines , this result is affected by some uncertainties . in grb060418 we identify crii and znii lines . such elements tend to stay in the gas state , minimizing the uncertainty when estimating the metallicity . no h features are present in this grb spectrum , so we derive the @xmath10 column from the x - ray data , leading to : z(cr ) @xmath11 and z(zn ) @xmath12 , a bit higher than for the other two grbs , but still below the solar values . the absorption spectra of grb afterglows are extremely complex , featuring several systems at different redshifts . both high and low ionization lines are observed in the circumburst environment , but their relative abundances vary from component to component , indicating a clumpy environment consisting of multiple shells . fine structure lines give information on the temperature and electron density of the absorbing medium , provided that they are excited by collisional effects . different components have different densities , suggesting a variable density profile . metallicity can be derived from the metal column densities ; crii and znii are the best indicators , since they do not form dust . metallicity values around @xmath9 with respect to the solar ones have been found . more details can be found in v. delia , f. fiore , e.j.a meurs et al . 2006 ( submitted to a&a , astro - ph/0609825 , 2006 ) .
Abstract: | [
"we present early time , high resolution spectroscopy of three grb afterglows : grb050730 , 050922c and 060418 . these data give us precious information on the kinematics , ionization and metallicity of the interstellar matter of grb host galaxies up to a redshift z @xmath0 , and of intervening absorbers along the line of sight . [ 1999/12/01 v1.4c il nuovo cimento ]"
] | 683 | 683 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: recent measurements of o stars winds indicate that their mass loss rates , @xmath0 , may be significantly less than previous estimates and expectations ( e.g. , massa et al . 2003 , repolust et al . 2004 , bouret et al . 2005 , fullerton et al . the primary mass loss diagnostic used in these analyses is p v @xmath1 . although wind models predict that the ion fraction of p@xmath2 should approach 100% in the winds of mid- to late o stars , this is a na - like ion , and can be quite fragile . consequently , it is important to verify the results based on p v. like phosphorus , sulfur is a non - cno element with a relatively low cosmic abundance . three sulfur mass loss diagnostics are available : the s iv @xmath3 1062 , 1072 and s vi @xmath4 933 , 944 resonance doublets , and the s v @xmath5 1502 excited state line populated by the s v @xmath5 786 resonance line . for wind conditions , the lower level of 1502 is populated exclusively by radiative excitation . in this case , its radial optical depth in the wind is ( see , lamers et al . , 1987 ) : @xmath6_{\nu}\ ] ] thus , while sulfur provides access to three adjoining stages of ionization , it introduces a model dependency through the flux term , @xmath7_{\nu}$ ] . s iv , s v and s vi occur together in luminous o4 o 6 stars with massive winds . s v was analyzed in both lmc and galactic stars , using the sei code ( lamers et al . , 1987 ) and rotationally broadened tlusty models were used for both the uv and euv continua . the results are shown in figure 1 . the derived @xmath8s v ) should be accurate to better than @xmath9% . preliminary sulfur results give _ total _ sulfur mass loss rates , @xmath10 , between 0.04 0.18 times smaller than those expected from either theoretical ( vink et al . 2000 ) or radio or h@xmath11 determinations ( see , fullerton et al . these results are similar those determined by the p v analyses . clumping and porosity can influence the results , and must be incorporated into the analysis to determine exact factors . nevertheless , it seems that the mass loss rates of o stars will have to be revised downward by some amount . we intend to extend the current analysis to a much larger sample and to investigate the effects of clumping more closely . * figure 1 : * fits to the program stars . the data are faint , solid curves , and the fits are heavy solid curves . models with @xmath12 equal to twice and half of the best fit values are shown as dashed curves . the values of @xmath13 implied by the fits are between 0.04 and 0.18 of the expected values .
Abstract: | [
"the winds of stars with very specific temperatures and luminosities are ideal for determining the magnitude and nature of mass loss in ob stars . i identify these stars and analyze their wind lines . the results are discussed within the context of recent findings which appear to indicate that the mass - loss rates of ob stars may as much as an order of magnitude less than commonly accepted values ."
] | 594 | 594 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: the diffuse intra - group light ( igl ) component is a useful tool to measure the intensity of the tidal interactions suffered by the galaxies and to map the extension and shape of the groups gravitational potential and the dark matter halo . in order to isolate the igl we used the `` trous '' wavelet transform with a multi - scale vision model ( ov_wav epitcio pereira , rabaa & da rocha 2005 ; da rocha & mendes de oliveira 2005 ) , which does not depend on `` a priori '' information . the process detects different characteristic size structures , separating the types of light source in the image . we have studied 3 hickson compact groups ( hickson 1982 ) , in different evolutionary stages , ( hcg 79 , hcg 88 and hcg 95 ) as a pilot study for an igl survey . simulated images were analyzed with ov_wav and showed that we are able to detect low - surface brightness extended structures , down to a @xmath3 per pixel , which corresponds to a 5-@xmath4-detection level in wavelet space . we have detected igl in hcg 79 and hcg 95 . hcg 79 has an irregular igl distribution , which closely matches the x - ray distribution ( pildis et al . 1995 ) and is bluer than the galaxies ( ( b - r ) = 1.5 ) , possibly a mix of stripped material from the outer parts of the galaxies and blue dwarf galaxies destruction . hcg 95 has an almost spherical igl distribution , with colors typical of old stellar populations . non - detection of igl in hcg 88 indicating an early stage of dynamical evolution . we suggest an evolutionary sequence : hcg 79 , in an advanced stage of dynamical evolution ; hcg 95 , intermediate stage ; and hcg 88 , initial epoch still without igl . the presence of an igl component indicates gravitationally bound configurations in which tidal encounters already stripped a considerable fraction of mass from the member galaxies and an advanced stage of dynamical evolution , providing a test for formation and evolution models of groups . to @xmath5 magnitudes for hcg 79 ( left ) and from @xmath6 to @xmath7 magnitudes for hcg 95 ( right ) . [ figdif],title="fig:",width=136 ] to @xmath5 magnitudes for hcg 79 ( left ) and from @xmath6 to @xmath7 magnitudes for hcg 95 ( right ) . [ figdif],title="fig:",width=147 ] da rocha , c. & mendes de oliveira , c. 2005 , mnras , in press epitcio pereira , d. n. , rabaa , c. r. & da rocha , c. 2005 , in preparation hickson , p. 1982 , apj , 255 , 382 pildis , r. a. , bregman , j. n. & evrard , a. e. 1995 , apj , 443 , 514
Abstract: | [
"we have analyzed the intra - group light component of 3 hickson compact groups ( hcg 79 , hcg 88 and hcg 95 ) with detections in two of them : hcg 79 , with @xmath0 of the total @xmath1 band luminosity and hcg 95 with @xmath2 . hcg 88 had no component detected . this component is presumably due to tidally stripped stellar material trapped in the group potential and represents an efficient tool to determine the stage of dynamical evolution and to map its gravitational potential . to detect this low surface brightness structure we have applied the wavelet technique ov_wav , which separates the different components of the image according to their spatial characteristic sizes ."
] | 572 | 572 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: dv psc is a rs cvn - type eclipsing binary with high - level surface activity , which is characterized by the light - cuvre asymmetries ( robb et al . , 1999 ; vanko et al . , 2007 ; zhang & zhang , 2007 ; zhang et al . , 2010 ; parimucha et al.,2010 ) and @xmath1 h & k emission ( beer 1994 ) . therefore , it is a very intriguing object for studying stellar magnetic activity . our new ccd photometric observations of dv psc ( fig . 1 ) were made in four observing runs : 2010 nov . 19 , 20 , and 2011 oct . 12 and 13 , dec . 08 and 10 with 85 cm telescope ( zhou et al . , 2009 ) at xinglong station of the national astronomical observatories of china ( @xmath2 ) . the spectroscopic observations of dv psc were obtained with the 2.16 m telescope at xinglong station on 2012 feb . 2 ) . the omr spectrograph centered at about 4280 @xmath3 with a reciprocal dispersion of 1.03 @xmath3 ( fang et al . , 2010 ) . + multi - color light - curve analyses were carried out using the wilson- devinney program ( wilson & devinney 1971 ; etc ) . the spot models are used to explain light - curve asymmetry based on the prior photometric solution ( zhang et al . the theoretical and observed light - curve are both displayed in figure 1 . the normalized spectra of dv psc were analyzed in the @xmath1 h & k , h@xmath4 and h@xmath5 lines with the spectral subtraction technique , which was described in detail by barden ( 1985 ) and montes et al . + h&k , h@xmath5 and h@xmath4 lines . the dotted lines represent the synthesized spectra and the upper are the subtracted ones.,title="fig:",width=96 ] h&k , h@xmath5 and h@xmath4 lines . the dotted lines represent the synthesized spectra and the upper are the subtracted ones.,title="fig:",width=96 ] h&k , h@xmath5 and h@xmath4 lines . the dotted lines represent the synthesized spectra and the upper are the subtracted ones.,title="fig:",width=96 ] the results can be summarized as follows : 1 . an updated linear ephemeris formula min.i = jd(hel.)2454026.1424(2 ) + 0.30853609(8)e was obtained . fitting all available light minimum times with a polynomial function showed that the orbital period of dv psc increased ( fig . our photometric and spectral results demonstrate that dv psc is very active . new four flare events of dv psc were found and the flare rate is about 0.017 flares per hour ( fig . the three flare - like events might be detected firstly in one period . the relation of the flare maximum amplitude and the flare duration of late - type stars ( kozhevnikova et al . , 2006 ; vida et al . , 2009 ; qian et al . , 2012 ; zhang et al . 2012 , etc ) are displayed in figure 3 . the magnetic active cycle may be 9.26(@xmath60.78 ) year , which was analyzed by the variabilities of max.i - max.ii ( fig . 3 ) . we will monitor later . we are very grateful to dr . montes d. , gu s. h. , han j. l. , zhou a. y. , zhou x. , jiang x. j. , zhao y. h. , and fang x. s. the work is supported by the _ nsfc _ under grant no . 10978010 , 11263001 , 11203005 and 10373023 . this work is partially supported by the open project program of the key laboratory of optical astronomy , _ naoc , cas_.
Abstract: | [
"we present our new photometry of dv psc obtained in 2010 and 2011 , and new spectroscopic observation on feb . 14 , 2012 . during our observations , three flare - like events might be detected firstly in one period on dv psc . the flare rate of dv psc is about 0.017 flares per hour . using wilson - devinney program , we derived the preliminary starspot parameters . moreover , the magnetic cycle is 9.26(@xmath0 ) year analyzed by variabilities of max.i - max.ii ."
] | 711 | 711 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: the creation of public archives of high - value observational data ( e.g. , nasa s hsearc ) has been a great boon to astronomical research in the past decade . it has given rise to a new kind of astronomer the archival astronomer who is free to check the methods and results of the data s authors , as well as to pursue independent , and sometimes novel , lines of inquiry . archival astronomy is expected to grow in scope and importance in the coming decade . by creating this archive of simulated x - ray clusters , we hope to extend this concept into the computational realm where simulations are growing in size and complexity . our goal is to produce large , statistical catalogs of @xmath1 100 clusters simulated at high resolution for two cases : ( 1 ) with , and ( 2 ) without non - adiabatic physical processes , in order to : @xmath2 understand the role of non - adiabatic processes in x - ray clusters , + @xmath2 make definitive predictions of the xlf evolution in both cases , + @xmath2 compare degree of cluster substructure with observational samples , + @xmath2 determine frequency of cooling flows as a function of @xmath3 . + we simulate a @xmath0cdm model with parameters @xmath4 . the survey volume is @xmath5 mpc on a side . we employ a new hydro+n - body code @xcite which uses adaptive mesh refinement to place high resolution grids where needed . first , a survey calculation was performed with @xmath6 cells , @xmath7 particles , and two levels of refinement everywhere to locate the clusters in our sample . then , each cluster is recomputed with up to 7 levels of refinement within the cluster environment . the dm mass resolution is @xmath8 ; the l7 spatial resolution is @xmath9 kpc . the adiabatic ( control ) sample is near completion and being analyzed . preliminary results focusing on the ten brightest clusters have been reported in @xcite and a second , more extensive paper is in preparation . amr simulation data structures are hierarchical and complex , and require specialized software for their manipulation and analysis @xcite . one of the design goals of the sca was to shield the user from the complexity ( and size ) of amr simulation data . we accomplished this by developing the sca as a workbench - style system that lets users interact with the archived data over the web . the user begins by selecting a cluster from a catalog list or a 3d vrml map . the server then retrieves the raw amr data from ncsa s mass storage system . once the data is on the sca web server , the user extracts from the amr files particle data and field data sampled to a uniform grid of user - specified size and resolution . at this point , the user may export the extracted data as hdf files for local analysis or use the suite of analysis tools provided as a part of the sca . the tools , which include 2d and 3d visualization tools , x - ray and sz imager , and graphing tool , are implemented as thin java applets in a client- server model . more detail can be found in @xcite . 99 bryan , g. l. & norman , m. l. , 1999 , in _ structured adaptive mesh refinement ( samr ) grid methods _ , eds . s. baden et al . , i m a vol . 117 , ( springer , new york ) , p. 165 burns , j. , loken , c. , rizza , e. , bryan , g. & norman , m. 1999 , in _ proceedings of @xmath10 texas symposium _ , eds . j. paul , t. montmerle & e. aubourg , _ in press _ daues , g. , currie , c. , anninos , p. , kohler , l. , shalf , j. & norman , m. 1999 , in _ astronomical data analysis software and systems viii _ , eds . d. mehringer , r. plante & d. roberts , asp vol . 172 , ( asp , san francisco ) , p. 241 norman , m. , shalf , j. , levy , s. & daues , g. 1999 , _ ieee computing in science and engineering _ , july / august , p. 36
Abstract: | [
"we have simulated the evolution of a large sample of x - ray clusters in a @xmath0cdm universe at high spatial resolution using adaptive mesh refinement and placed the results in an online archive for public access . the simulated cluster archive website sca.ncsa.uiuc.edu provides tools for interactive 2d and 3d analysis of gas and dark matter fields , x - ray and sz imaging , and data export . we encourage community use and solicit their feedback ."
] | 840 | 840 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: from its beginnings , progress in qcd at low energies has been impeded because there are no good analytical tools available in order to work with strongly coupled yang mills theories . nevertheless , in the last few years the ads / cft ideas has provided a new approach that could improve this situation . at present a dual to qcd is unknown , but a simple approach known as bottom - up has been quite successful in several concrete qcd applications , such as in hadronic scattering processes @xcite , hadronic spectra @xcite , hadronic couplings and chiral symmetry breaking @xcite , mesonic wave function @xcite , among other applications . here we summarize the main ideas developed in @xcite , where a soft wall holographical model that describes hadronic spectra with an arbitrary number of constituents was proposed . the present work has been structured as follow . section ii is a summary of the model considered . in section iii we give some examples , and finally in iv we present some conclusions . we begin by considering an asymptotically ads space defined by @xmath0 and an action for arbitrary spin modes ( which depends on the spin of the hadron described ) . [ cols="^,^ " , ] on the other side , solutions to rarita - schwinger equation in ads space are more difficult to get , but its spectrum is similar to the dirac case , as you can see for example in ref . @xcite . as is possible to see in fig 2 , again the results are somewhat high , but using @xmath1 , adjusted to @xmath2 resonances gives better results . the holographical model discussed here allowed us to obtain hadronic spectra with regge behavior , not only for the integer spin case , but also for spins 1/2 and 3/2 , and also to calculate masses for exotics . in order to do this we considered anomalous dimensions for operators that create hadrons , and the dilaton that was used has a form suggested by einstein s equations , corresponding to the ads metric . this two traits allowed the model to reproduce regge spectra in all cases considered , and therefore the model can describe hadronic masses in a unified phenomenological model . j. polchinski and m. j. strassler , phys . lett 88 , 031601 ( 2002 ) ; r. a. janik and r. peschanski , nucl . phys b565 , 193 ( 2000 ) ; s. j. brodsky and g. f. de tramond , phys . lett b582 , 211 ( 2004):e . levin , j. miller , b. kopeliovich and i. schmidt , e - print : arxiv:0811.3586 [ hep - ph ] s. j. brodsky and g. f. de tramond , phys . lett 94 , 201601 ( 2005 ) ; a. karch , e. katz , d. t. son and m. a. stephanov , phys . rev d74 , 015005 ( 2006 ) ; s. j. brodsky and g. f. de tramond , arxiv : 0802.0514 v1 [ hep - ph ] . l. da rol and a. pomarol , nucl . phys b721 , 79 ( 2005);j . erlich , e. katz , d. t. son and m. a. stephanov , phys . lett 95 , 261602 ( 2005 ) ; p. colangelo , f. de fazio , f. giannuzzi , f. jugeau and s. nicotri , phys . d * 78 * , 055009 ( 2008 ) [ arxiv:0807.1054 [ hep - ph ] ] . s. j. brodsky and g. f. de teramond , phys . * 96 * , 201601 ( 2006 ) [ arxiv : hep - ph/0602252 ] ; s. j. brodsky and g. f. de teramond , phys . d * 77 * , 056007 ( 2008 ) [ arxiv:0707.3859 [ hep - ph ] ] ; a. vega , i. schmidt , t. branz , t. gutsche and v. e. lyubovitskij , phys . d * 80 * , 055014 ( 2009 ) [ arxiv:0906.1220 [ hep - ph ] ] . i. kirsch , jhep09 ( 2006 ) 052 . w. de paula , t. frederico , h. forkel and m. beyer , phys . d * 79 * , 075019 ( 2009 ) [ arxiv:0806.3830 [ hep - ph ] ] ; u. gursoy and e. kiritsis , jhep0802 : 032 , 2008 ; u. gursoy , e. kiritsis and f. nitti , jhep0802 : 019 , 2008 .
Abstract: | [
"we present an holographical soft wall model which is able to reproduce regge spectra for hadrons with an arbitrary number of constituents . the model includes the anomalous dimension of operators that create hadrons , together with a dilaton , whose form is suggested by einstein s equations and the ads metric . address = departamento de fsica y centro de estudios subatmicos , + universidad tcnica federico santa mara , + casilla 110-v , valparaso , chile"
] | 845 | 845 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: rooted in the book of job , `` behemoth '' is a worthy accolade to bestow upon the class of red supergiants . this finds reason in the popular use of the word . thinking of the namesake polish death metal band , red supergiants are dying stars , and their explosive death sparks the production and distribution of metals . in the cult game final fantasy , behemoths are beasts most feared for their magic spell `` meteor '' ; indeed , red supergiants fabricate dust grains , a process enshrouded in mystery . princeton university s farlex wordnet describes behemoths as `` abnormally large and powerful '' , `` unusual '' , `` of exceptional importance and reputation '' , and that `` strongly influence the course of events '' all applicable to red supergiants . and they are , simply put , `` whoppers '' . descendent from stars with birth masses in the region of 830 m@xmath0 , red supergiants become large , hundreds of r@xmath0 up to more than a thousand r@xmath0 , because their mantles become convective . the reason they become convective is because the energy production rate in the core can no longer be balanced by radiative diffusion and instead bulk motion is induced to transport the energy to the surface . this causes a drastic restructuring of the mantle , with a much shallower density gradient . it becomes optically thin at much larger radial distance from the core , and hence the temperature of the plasma where this happens is relatively low , @xmath14000 k , such that equilibrium is maintained ( @xmath2 ) . to put this in perspective , a massive main sequence star would easily fit within the orbit of mercury , but its red supergiant progeny could swallow jupiter . at that point , it would take more than a decade to travel around its surface at a speed of 10 km s@xmath3 , which is little more than the thermal motions in the star s atmosphere but only a few times smaller than the escape speed from its surface . hence red supergiants oscillate on timescales of years , and their winds have speeds of just a few tens of km s@xmath3 taking tens of thousands of years for matter to move out to one parsec distance . this means that we may be able to read the immediate past of the red supergiant even if it is no longer there in the story told by its circumstellar medium . the low escape speed makes it easy for these stars to lose mass , but it critically depends on how long they spend their time doing this , how much mass they eventually will have lost . it also means that rotation at the mere km s@xmath3 level may already affect these stars . red supergiants matter , as actors and probes in processes that drive galaxy evolution . but there are some important aspects of their formation , evolution and behaviour that need to be better understood : + + and finally , if close binary interaction does affect the evolution of a large fraction of the massive star population ( ( * ? ? * de mink ( 2014 ) ) , then observational and theoretical efforts must be promoted that aim to quantify these effects . 2012 , _ a&a _ , 548 , 113 2014 , _ apj _ , 782 , 7 2009 , _ a&a _ , 508 , 923 2014 , _ apj _ , 782 , l2 2015 , _ mnras _ , 447 , 3973 2009 , _ a&a _ , 504 , 115 2011 , _ a&a _ , 531 , 117 2015 , _ apj _ , 799 , 50 2006 , _ apj _ , 645 , 1102 2007 , _ apj _ , 667 , 202 2013 , _ a&a _ , 560 , 16 2011 , _ science _ , 333 , 1258 2015 , , 575 , 60 2012 , _ nature _ , 482 , 375 2013 , _ mnras _ , 433 , 1246 2015 , _ pasa _ , 32 , 16 2015 , _ apj _ , 799 , 158 2010 , _ aspc _ , 425 , 279 2013 , _ eas _ , 60 , 307 1999 , _ a&a _ , 351 , 559 2005 , _ a&a _ , 438 , 273
Abstract: | [
"as the opening review to the focus meeting `` stellar behemoths : red supergiants across the local universe '' , i here provide a brief introduction to red supergiants , setting the stage for subsequent contributions . i highlight some recent activity in the field , and identify areas of progress , areas where progress is needed , and how such progress might be achieved ."
] | 839 | 839 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: @xcite has suggested that bulges in spiral galaxies can be classified into _ classical bulges _ or _ pseudobulges_. classical bulges are thought to form through galactic merger . pseudobulges are discussed to form through secular evolution caused by non - axisymmetric structures in a galactic disc . @xcite demonstrated that clumpy structures form due to gas instability , which could also explain some clumpy galaxies observed in the high - redshift universe . these galaxies are referred to as clump clusters ( chain galaxies ) . @xcite suggested that these clumpy stellar structures fall into the galactic centre by dynamical friction and merge into a single bulge at the galactic centre , a clump - origin bulge . clump - origin bulges form through ` _ _ mergers of the clumps _ _ ' in a galactic disc , neither the galactic merger nor the secular evolution . therefore , properties of clump - origin bulges could be different from those of the conventional ones , classical bulges nor pseudobulges . i perform a similar numerical simulation to @xcite using an isolated halo model by a @xmath0-body / sph code and study the naive natures of clump - origin bulges in details . our initial condition follows the spherical model that was used to study the formation of disc galaxies in an isolated environment . i assume an equilibrium system with the nfw profile with a virial mass @xmath1 . baryon mass fraction of the system is set to @xmath2 . the details of my simulation settings are given in @xcite . in fig . [ fig:1 ] , i plot the azimathally averaged surface density and density map from the edge - on view . the fitting is given by the srsic index , @xmath3 indicating a nearly exponential density profile . as seen from the central panel , it clearly appears that this bulge is a boxy bulge from the edge - on view . furthermore , i find that this bulge shows a significant rotation with a value of @xmath4 , the rotation ( spin ) is _ not _ negligible in kinematics . these are indicating pseudobulge signatures @xcite . however , i find that the clump - origin bulge consists of stars with an over - solar metallicity @xcite . additionally , this bulge formation scenario , the clump cluster phase , is expected to happen only at the high - redshift . therefore , the clump - origin bulge consists of old stars . such old and metal - rich natures are better similar to classical bulges rather than pseudobugles @xcite . the mw bulge is also known to be an ambiguous bulge . the mw bulge shows a nearly exponential profile , an oblate peanut shape ( x - shape ) and a significant rotation , which are similar to pseudobulges . at the same time , the mw bulge is made of old and metal - rich stars , which are classical bulge signatures @xcite . these properties of the mw bulge are consistent with the clump - origin bulge obtained in this study . such unclassifiable bulges ( old pseudobulge ) are also observed in some other disc galaxies @xcite . my simulation results imply that such old pseudobulges like the mw bulge may be a clump - origin bulge and the mw might use to be a clump cluster .
Abstract: | [
"bulges in spiral galaxies have been supposed to be classified into two types : classical bulges or pseudobulges . classical bulges are thought to form by galactic merger with bursty star formation , whereas pseudobulges are suggested to form by secular evolution . @xcite suggested another bulge formation scenario , ` clump - origin bulge ' . he demonstrated using a numerical simulation that a galactic disc forms clumpy structures in the early stage of disc formation , then the clumps merge into a single bulge at the centre . i perform a high - resolution @xmath0-body / sph simulation for the formation of the clump - origin bulge in an isolated galaxy model . i find that the clump - origin bulge resembles pseudobulges in dynamical properties , but this bulge consists of old and metal - rich stars . these natures , old metal - rich population but pseudobulge - like structures , mean that the clump - origin bulge can not be simply classified into classical bulges nor pseudobulges . from these results , i discuss similarities of the clump - origin bulge to the milky way ( mw ) bulge ."
] | 660 | 660 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: the cyg x-1 data presented here were obtained by the pca onboard rxte , mostly gained through our monitoring campaign 19982002 ( for a description of the data see @xcite ) . we split each light curve into segments of 1s length and determine the mean flux of each segment . the segments are binned into 41 equally segmented flux bins , for each of which we calculate the power spectral density ( psd ) of all contained lightcurve segments via the dft ( see , e.g. , ) . from all periodograms of each flux bin the mean psd is determined using standard methods . for better statistics we chose to take into account only flux bins containing at least 20 periodograms . integrating the poisson noise corrected psd over the range @xmath0@xmath1hz , we arrive at the squared fractional rms variability . in a next step we multiply the fractional rms variability by the mean flux of the bin , to obtain the absolute rms variability @xmath2 . for all bins of each observation we plot @xmath2 over flux @xmath3 and fit a linear function in two different representations . by fitting @xmath4 , two characterizing values are determined : slope @xmath5 and intercept @xmath6 on the @xmath2 axis . the gradient of the @xmath2-@xmath3-trend @xmath5 is equivalent to the fractional rms variability of the light curve . alternatively to intercept @xmath6 , it was proposed to determine the physically meaningful intercept @xmath7 on the @xmath3 axis by fitting @xmath8 @xcite . if @xmath5 is interpreted as the variable component of the lightcurve , then @xmath7 represents a second component of it which does not follow the linear @xmath2-@xmath3-trend . in deriving results , it should be kept in mind that @xmath7 , which is identical to @xmath9 , and @xmath5 are not independent values for the characterization of the rms - flux - relation . generally , there is a good linear relationship between @xmath2 and @xmath3 in the hard state , which is reflected by the stable pearson correlation coefficient in fig . [ fig : rmsfluxvstime ] . we also notice coincidence of the change of the general long term behavior of cyg x-1 from a `` quiet hard state '' to a `` flaring hard state '' in 1998 may @xcite with a shift in the values of slope @xmath5 and the intercepts . the shape of the rms - flux - relation in the soft states of 1996 and 2001/2002 changes continuously between waviness and approximate linearity ( see fig . [ fig : softstate ] ) . during `` failed state transitions''(fst ) , i.e. , during times when the source reached its intermediate state , the linear rms - flux relation breaks down . we examined four fst : 1998 july 15 , 1999 dec 05 , 2000 nov 03 , and 2001 jan 29 ( indicated in fig . [ fig : rmsfluxvstime ] by dotted lines ) . comparing these events with the neighboring hard state observations , we notice that the rms - flux - relations of 1999 december 05 and 2000 november 03 being strictly linear before and after change to an arch - like appearance during the fst itself ( see fig . [ fig : failed ] ) . the other two examined fst also deviate from the linear relation , but these deviations are not as prominent . an explanation of the rms - flux - relation seems to be the modification of a theory which explains the psd of gbhc by the superposition of accretion disk ( ad ) instabilities occuring at several radii in the ad that are propagated towards the innermost region of the disk . local @xmath10 variations , which are caused by short term changes of the disk viscosity and whose time scale is dependent on radius , are superimposed on long term @xmath10 modulations . if the fractional amplitude of the @xmath10 variations is independent of the long term @xmath10 , a linear flux - rms relation will be observed @xcite . the rms - flux - relation will break down if the corona is severely disturbed this seems to be the case during the intermediate state of cyg x-1 , in agreement with earlier results for the behavior of x - ray time lags @xcite . here , the observed x - ray time lag is much larger than during the normal hard state , which could indicate changes in the geometry of the ad corona , possibly related to the observed radio emitting outflow .
Abstract: | [
"a linear dependence of the amplitude of broadband noise variability on flux for gbhc and agn has been recently shown by uttley & mchardy @xcite . we present the long term evolution of this rms - flux - relation for cyg x-1 as monitored from 19982002 with rxte . we confirm the linear relationship in the hard state and analyze the evolution of the correlation for the period of 19962002 . in the intermediate and the soft state , we find considerable deviations from the otherwise linear relationship . a possible explanation for the rms - flux - relation is a superposition of local mass accretion rate variations ."
] | 858 | 858 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: since its discovery in 1974 , the @xmath0 meson has provided a useful laboratory for quantitative tests of quantum chromodynamics ( qcd ) and , in particular , of the interplay of perturbative and nonperturbative phenomena . the factorization formalism of nonrelativistic qcd ( nrqcd ) @xcite provides a rigorous theoretical framework for the description of heavy - quarkonium production and decay . this formalism implies a separation of short - distance coefficients , which can be calculated perturbatively as expansions in the strong - coupling constant @xmath3 , from long - distance matrix elements ( mes ) , which must be extracted from experiment . the relative importance of the latter can be estimated by means of velocity scaling rules , i.e. the mes are predicted to scale with a definite power of the heavy - quark ( @xmath4 ) velocity @xmath5 in the limit @xmath6 . in this way , the theoretical predictions are organized as double expansions in @xmath3 and @xmath5 . a crucial feature of this formalism is that it takes into account the complete structure of the @xmath7 fock space , which is spanned by the states @xmath8 with definite spin @xmath9 , orbital angular momentum @xmath10 , total angular momentum @xmath11 , and colour multiplicity @xmath12 . the hierarchy of the mes predicted by the velocity scaling rules is explained for the @xmath0 , @xmath13 , and @xmath14 mesons in table [ tab : vsr ] . in particular , this formalism predicts the existence of colour - octet ( co ) processes in nature . this means that @xmath7 pairs are produced at short distances in co states and subsequently evolve into physical , colour - singlet ( cs ) quarkonia by the nonperturbative emission of soft gluons . in the limit @xmath15 , the traditional cs model ( csm ) @xcite is recovered . the greatest triumph of this formalism was that it was able to correctly describe @xcite the cross section of inclusive charmonium hadroproduction measured in @xmath16 collisions at the fermilab tevatron @xcite , which had turned out to be more than one order of magnitude in excess of the csm prediction . .values of @xmath17 in @xmath18\right\rangle\propto v^k$ ] for @xmath19 . [ cols="^,^,^",options="header " , ] inclusive @xmath0 production in dis lends itself as a sensitive probe of the co mechanism . as for @xmath20 , the h1 data @xcite generally confirms nrqcd and disfavours the csm @xcite . however , nrqcd predicts at lo a distinct rise in cross section as @xmath21 , which is not reflected by the h1 data . this anomaly is familiar from photoproduction , and it is likely to be resolved by the inclusion of higher - order corrections @xcite , possibly in combination with intrinsic-@xmath22 effects and/or nonperturbative shape functions . as for @xmath23 , the chorus central value for the total cross section @xcite exceeds the lo prediction @xcite by almost one order of magnitude . however , the experimental error is still rather sizeable . as for @xmath24 , co processes are dominant , diffractive ones are absent , and the experimental signature is spectacular , so that a measurement would be worthwhile @xcite . inclusive @xmath0 production in cc dis represents a challenge for hera and thera . cdf collaboration , f. abe et al . lett . 69 ( 1992 ) 3704 ; 71 ( 1993 ) 2537 ; 79 ( 1997 ) 572 ; 79 ( 1997 ) 578 ; d0 collaboration , s. abachi et al . , phys . b 370 ( 1996 ) 239 ; d0 collaboration , b. abbott et al . , phys . rev . lett . 82 ( 1999 ) 35 . m. beneke and m. krmer , phys . d 55 ( 1997 ) 5269 ; a.k . leibovich , phys . d 56 ( 1997 ) 4412 ; m. beneke , m. krmer , and m. vnttinen , phys . d 57 ( 1998 ) 4258 ; b.a . kniehl and j. lee , phys . rev . d 62 ( 2000 ) 114027 ; s. fleming , a.k . leibovich , and i.z . rothstein , phys . d 64 ( 2001 ) 036002 . todorova - nov , in _ proceedings of the xxxi international symposium on multiparticle dynamics ( xxxi - ismd ) _ , datong , china , september 17 , 2001 , edited by b. yuting , y. meiling , and w. yuanfang , econf c010901 ( 2001 ) ; m. chapkin , talk presented at _ 7th international workshop on meson production , properties and interaction ( meson 2002 ) _ , krakow , poland , 2428 may 2002 .
Abstract: | [
"we discuss the inclusive production of @xmath0 mesons in deep - inelastic scattering ( dis ) via the electromagnetic , weak neutral , and charged currents within the factorization formalism of nonrelativistic quantum chromodynamics . theoretical predictions are confronted with experimental data of @xmath1 and @xmath2 dis taken by the h1 collaboration at desy hera and the chorus collaboration at cern , respectively ."
] | 878 | 878 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: during the recent gregorian upgrade of the arecibo telescope , considerable effort was put into drift scan searches of the arecibo sky ( @xmath0 ) for new pulsars . the stsci / naic group was assigned declination strips centered at 1.5@xmath1 , 6.5@xmath1 , 11.5@xmath1 , 16.5@xmath1 , 21.5@xmath1 , 26.5@xmath1 , 31.5@xmath1 , and 36.5@xmath1 . a list of 20 candidates was compiled from a search in these areas between 1994 and 1998 . we have so far confirmed eight new pulsars as a result of these observations . the nominal parameters based on the confirmation observations are summarized in table 1 . barycentric periods have uncertainties of order one unit in the last digit quoted , while a conservative estimate of the uncertainty in the dispersion measures ( dm ) is @xmath2 @xmath3 pc . the positions are presently uncertain by of order @xmath4 arcmin in right ascension and declination equivalent to the half power beam size of the telescope at 430 mhz . although we presently have no long - term estimates of the flux densities of the new pulsars , it is already clear that they are weak sources with typical flux densities of order 0.5 to 1 mjy . some of the initial detections were probably significantly facilitated by flux amplifications due to interstellar scintillation . inferred 430-mhz luminosities , based on their fluxes and dispersion measures estimates range between 3 and 30 mjy kpc@xmath5 . these pulsars , along with those discovered by other groups during the arecibo upgrade , should greatly assist future statistical studies of the low end of the pulsar luminosity function . more accurate measurements of the flux densities , as well as the spin and astrometric parameters for each source are presently underway at arecibo as part of a regular timing program using the penn state pulsar machine . llllll psr & r.a . & decl . & period & epoch & dm + & & ( sec ) & ( mjd ) & @xmath3 pc + j0137 + 16 & 01:37:31 & + 16:55 & 0.41477 & 51264 & 26 + j0329 + 16 & 03:29:13 & + 16:54 & 0.8933 & 51257 & 35 + + j1549 + 21 & 15:49:41 & + 21:14 & 1.262 & 51335 & 55 + j1822 + 11 & 18:22:17 & + 11:22 & 1.787 & 51261 & 112 + + j1838 + 16 & 18:38:52 & + 16:53 & 1.902 & 51261 & 36 + j1849 + 06 & 18:49:07 & + 06:07 & 2.219 & 51258 & 236 + + j1905 + 06 & 19:05:21 & + 06:23 & 0.9897 & 51261 & 262 + j2040 + 16 & 20:40:13 & + 16:54 & 0.8656 & 51261 & 51 +
Abstract: | [
"the unique sensitivity of the arecibo telescope at 430 mhz motivated a drift scan search of the visible sky divided up into eight declination strips . based on an analysis of the data collected in the region assigned to us , eight new long - period pulsars have so far been discovered . 1.25 in .125 in .25 in"
] | 550 | 550 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: 55 cancri (= hd 75732 ) is a late g / early k dwarf / subgiant currently known to host five extrasolar planets with periods between around 0.7 days and 14 years and minimum masses between 0.026 and 3.84 @xmath5 . the super - earth 55 cnc e was recently discovered to transit ( winn et al . 2011 , demory et al . 2011 ) , prompting a number of studies of the properties of this system ( e.g. , kane et al . 2011 , von braun et al . we used the chara interferometric array to directly measure the stellar angular diameter , which , when combined with hipparcos parallax measurement and calculation of bolometric flux based on spectral templates and literature broad - band photometry , yields the physical @xmath6 and @xmath7 ( von braun et al . details of our observations and calculations of stellar properties are described in von braun et al . ( 2011b ) . we give our results in table 1 . of particular interest are the location and extent of the circumstellar habitable zone ( hz ) , based on the equations of jones & sleep ( 2010 ) , and the physical radius of the transiting super - earth , based on simply the measured flux decrement during transit and our calculated stellar radius value . 1 illustrates that planet f , with its elliptical orbit ( @xmath8 ) , spends about 74% of its year inside the hz , while its equilibrium temperature varies between 221k ( apastron ) and 302k ( periastron ) for the assumption of perfect efficiency in the redistribution of energy received from the star ( von braun et al . 2011b ) . coupled with the recent literature values of assumed planetary mass and measured flux decrement during transit , our measured stellar radius implies @xmath9 and @xmath10 ( for @xmath11 = @xmath12 ; winn et al . 2011 ) , and @xmath13 and @xmath14 ( for @xmath11 = @xmath15 ; demory et al . 2011 ) . .stellar properties of the 55 cancri system . @xmath16 and @xmath17 correspond to the uniform disk and limb - darkening corrected angular stellar diameters , respectively . @xmath17 corresponds to the angular diameter of the rosseland , or mean , radiating surface of the star . [ cols=">,^ " , ]
Abstract: | [
"the bright star 55 cancri is known to host five planets , including a transiting super - earth . we use the chara array to directly determine the following of 55 cnc s stellar astrophysical parameters : @xmath0 , @xmath1 k. planet 55 cnc f ( @xmath2 ) spends the majority of the duration of its elliptical orbit in the circumstellar habitable zone ( 0.671.32 au ) where , with moderate greenhouse heating , it could harbor liquid water . our determination of 55 cancri s stellar radius allows for a model - independent calculation of the physical diameter of the transiting super - earth 55 cnc e ( @xmath3 ) , which , depending on the assumed literature value of planetary mass , implies a bulk density of 0.76 @xmath4 or 1.07 @xmath4 ."
] | 485 | 485 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: entanglement is one of the potential sources of quantum theory . it is the key concept and major resource for quantum communication and computation @xcite . in the last few years , enormous efforts has been made to investigate various aspects of quantum entanglement and its benefits in a number of setups , such as teleportation of unknown states @xcite , quantum key distribution @xcite , quantum cryptography @xcite and quantum computation @xcite . recently , the study of quantum entanglement of various fields has been extended to the relativistic setup @xcite and interesting results about the behavior of entanglement have been obtained . the study of entanglement in the relativistic framework is important not only from quantum information perspective but also to understand deeply the black hole thermodynamics @xcite and the black hole information paradox @xcite . the earlier investigations on quantum entanglement in the relativistic framework is mainly focused by considering isolated quantum systems . in fact , no quantum system can be completely isolated from its environment and may results in a non - unitary dynamics of the system . therefore , it is important to study the effect of environment on the entanglement in an initial state of a quantum system during its evolution . the interaction between an environment and a quantum system leads to the phenomenon of decoherence and it gives rise to an irreversible transfer of information from the system to the environment @xcite . [ cols="^,^,^ " , ] if we compare the single qubit and the both qubits decohering situations , it becomes obvious that the entanglement loss is rapid when both the qubits are coupled to the noisy environment . for example , in the case of bit flip channel the concurrence behaves as a linear function of @xmath0 for single qubit decohering case whereas in the case of both qubits decohering case it varies as a parabolic function . nevertheless , the sudden death happens at the same value of @xmath0 , irrespective of the acceleration , for both cases under the action of bit flip and phase damping channels . for depolarizing channel , however , this is not true . in conclusion , we have investigated that the entanglement in dirac fields is strongly dependent on coupling with a noisy environment . this result is contrary to the case of an isolated system in which the entanglement of dirac fields survives even in the limit of infinite acceleration of rob s frame . in the presence of decoherence , the entanglement rapidly decreases and entanglement sudden death occurs even for zero acceleration . under the action of phase flip channel , the entanglement can regrow when both qubits are coupled to a noisy environment in the limit of large values of decoherence parameter . the entanglement disappears , irrespective of the acceleration , under the action of phase damping channel only when the channel is fully decohered both for single qubit and the two qubits decohering cases . however , under the action of depolarizing channel an early sudden death occurs for larger acceleration when both qubits are coupled to the environment . in summary , the entanglement generated by unruh effect in noninertial frame is strongly influenced by decoherence .
Abstract: | [
"we study the effects of decoherence on the entanglement generated by unruh effect in noninertial frames by using bit flip , phase damping and depolarizing channels . it is shown that decoherence strongly influences the initial state entanglement . the entanglement sudden death can happens irrespective of the acceleration of the noninertial frame under the action of phase flip and phase damping channels . it is investigated that an early sudden death happens for large acceleration under the depolarizing environment . moreover , the entanglement increases for a highly decohered phase flip channel.pacs : 03.65.ud ; 03.65.yz ; 03.67.mn;04.70.dy keywords : entanglement ; decoherence ; noninertial frames ."
] | 633 | 633 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: in order to have an idea on the types of objects we can expect at flux levels accessible with ska we have modeled the main classes of sources detected at mjy and sub - mjy levels : steep agns ( radio galaxies ) modeled following dunlop & peacock ( 1990 , mnras , 247 , 19 ) ; flat agns ( sy1 and qso ) , for which we have assumed the quasar optical lf and evolution ( boyle et al 1988 , mnras , 235 , 935 ; 1991 , asp conf . 21 , p. 191 ; schmidt et al 1995 , aj , 109 , 473 ) ; the star - forming galaxies ( rlf from sadler et al 2002 , mnras , 329 , 227 ) composed by a fraction ( assumed 50% ) of non - evolving normal spirals and a fraction ( 50% ) of evolving starburst galaxies ( @xmath1 ) . passive optical evolution has been assumed whenever necessary ( poggianti 1997 , a&as , 122 , 399 ) . + a number of available surveys at the mjy , sub - mjy and jy level can provide important boundary conditions to any modelling of the radio sky . the radio counts are constrained by using all the samples available in the literature , while we focused on samples with optical spectroscopy follow - up to get constraints on the redshift and magnitude distributions of the sources . in particular we refer to the following samples : first ( magliocchetti et al . 2000 , mnras , 318 , 1047 ) , atesp - eis ( prandoni et al . 2001b ) , pdf ( phoenix deep field , georgakakis et al . 1999 , mnras , 306 , 708 ) , mf ( marano field , gruppioni et al . 1999 ) , b93 ( sample collection studied by benn et al . 1993 , mnras , 263 , 98 ) , h00 ( collection studied by haarsma et al . + the models used here provide a good fit to the observed number counts along the entire flux range spanned by the counts ( @xmath2 @xmath0jy - 1 jy ) and can reproduce the total number of sources in the comparison samples within a factor of 2 . the models can trace with good accuracy both the magnitude and the redshift distributions of the sources in the given samples . the models above have been used to simulate the radio sky at fainter flux levels than reached by the current surveys . the composition of the radio sky changes with flux as shown in figure [ eps1 ] . the figure clearly shows that radio galaxies , which dominate ( together with qso ) the mjy population , reappear in large proportions going to nanojy levels ( @xmath3 at @xmath4 njy ) ! + on the other hand , starburst galaxies and their evolution can be suitably studied with less sensitive surveys ( e.g. @xmath5 njy ) . the other main population at nanojy level is represented by non - evolving spirals , whose contribution shows a bump ( mainly due to @xmath6 galaxies ) in the range @xmath7 njy . + this work demonstrates that nuclear activity could be important at nanojy flux levels . deeper data are strongly needed to better constrain the models and provide more reliable simulations . this kind of analysis can provide very useful constraints to the design of ska .
Abstract: | [
"the apparent change in the composition of the parent optical objects of radio sources around 1 mjy ( at 1.4 ghz ) is now well established , although there is still some debate about the relative importance of classical radio galaxies and star - forming galaxies at sub - mjy levels ( see e.g. gruppioni et al . 1999 , mnras , 304 , 199 ; prandoni et al . 2001b , a&a , 369 , 787 ) . it is clear , however , that at @xmath0jy levels star - forming galaxies are dominant ( see fomalont et al . 1997 , apj , 475 , l5 ; haarsma et al . 2000 , apj , 544 , 641 ) . + does this mean that ska will basically tell us more about the history of star formation than about the space density ( and its cosmological evolution ) of active galactic nuclei ? + using current best estimates of luminosity functions ( and their evolution ) of various classes of objects , we show that the increasing dominance of star - forming galaxies below 1 mjy is a natural consequence of the different luminosity functions , but that this does not at all mean that star - forming galaxies do necessarily dominate at all sub - mjy flux levels and all redshifts ."
] | 675 | 675 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: the origin of ultra - high energy cosmic rays remains a fundamental and unsolved problem in astroparticle physics . promising clues could be provided by the associated high energy neutrinos since they would neither interact with intergalactic or interstellar media nor be deflected by the magnetic fields . various detectors have been proposed for detecting high energy neutrinos . some of them rely on measuring the air shower by the so - called earth - skimming @xmath1 , for which horizontal showers are generated by the ensuing @xmath2 decay@xcite . in this paper , we investigate the shower properties by simulations . equipped with the knowledge of the @xmath1 induced air shower , we are able to calculate the induced geosynchrotron radiation . in sec . ii , we present the corsika@xcite simulated shower profile to be employed in the calculation of geosynchrotron radiation in sec . our calculation is based on the coherent geosynchrotron emission scenario initiated in 1970s@xcite and further developed by huege and falcke@xcite . in sec . iv , we summarize and conclude our work . the tau decay induced air shower is initiated by the decay product . using corsika code , we simulate the shower initiated by electrons at five different energies . table [ stat ] presents the statistics of these simulations . the simulation shows that the shower particles reside in a shower thickness less than @xmath3 . compared with the radiation which traverses a distance of @xmath4 @xmath5 , the shower front at the shower maximum is treated as longitudinally coherent . the remaining structures are the lateral profile and lorentz factor distribution representing the spatial and energy distribution of the shower particles . .shower statistics [ cols="<,^,^,^ " , ] fig . [ gamma ] and [ lateral ] show the energy and position distributions of the shower particles at shower maximum for different energies . both are displayed in the unit normalized to the total number at the corresponding energies . having determined the spatial structure and energy distribution of shower particles , we can calculate the emission from the shower maximum . [ interfere ] depicts the expected electric field at different receiver locations . the interference pattern arises from the scale of the shower front . in fig . [ pulse ] , we calculate the pulse measured by the receiver with a given bandwidth . this plot indicates how large the separation between antennae can be for the current technology . for the maximum of a @xmath6 shower at the observation distance of @xmath7 . curves in blue , red and yellow represent signals in observing frequencies of @xmath8 , @xmath9 and @xmath10 , respectively.,width=302 ] shower at the observation distance of @xmath7 , using an idealized rectangular filter spanning @xmath11 . curves in blue , red and yellow denote pulses measured at center , at lateral distances of @xmath12 and @xmath13 , respectively.,width=302 ] in this work , we investigate properties of the earth - skimming tau neutrino induced shower . the universal behavior of the shower particle allows a simple parametrization which will be helpful in future calculations of the geosynchrotron radiation . our calculations also provide useful information for the future experiments .
Abstract: | [
"cosmogenic neutrinos@xcite are expected from ultrahigh energy cosmic rays undergoing the gzk process@xcite and anticipated to be observed by detecting air showers from the decays of tau leptons . we use corsika simulated shower structure to calculate the coherent geosynchrotron radio emissions of the tau decay showers above @xmath0ev . we present the pattern and spectrum of radio waves and discuss their detections by radio antennae ."
] | 629 | 629 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: ship bow waves exhibit both large and small scale features . the most prominent small scale feature is the bow wave crest formation of thin overturning sheets which break up into spray . re and we scale effects are large such that replication of full scale phenomena of the small scale features of ship bow waves is difficult even with large models . however , experimental studies for wedge flows display and document the small scale structures of bow waves . herein , flows around a wedge - shaped bow are numerically simulated with the aim of investigating the wave breaking mechanism and small scale features of ship bow waves . the side length of the wedge is l = 0.75 m , and the height of the wedge is h = 1.0 m. the half wedge angle is @xmath0 = @xmath1 and the flare angle @xmath2 = @xmath3 . the water depth is d = 0.0745 m and the upstream velocity is u = 2.5 m / s , the corresponding reynolds number , re = @xmath4 , and the froude number , fr = 2.93 .
Abstract: | [
"flows around a wedge - shaped bow are simulated with the aim of investigating the wave breaking mechanism and small scale features of ship bow waves . this fluid dynamics video shows the plunging wave breaking process around the wedge including the thin water sheet formation , overturning sheet with surface disturbance , fingering and breaking up into spray , plunging and splashing , and air entrainment ."
] | 277 | 277 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: the vimos integral field unit ( hereafter ifu ) allows to obtain one spectrum for each resolution element of its field of view , thanks to a square array of microlenses , each one coupled to an optical fiber . technical details about vimos ifu can be found in prieto et al . see also le fvre et al . ( 1998 ) . vimos ifu can be used in various configurations , outlined in table [ tab : ifuconf ] [ tab : ifuconf ] cccc field of view & spatial resolution & spectral resolution & number of fibers + 54@xmath0 54 & 067 & 250 & @xmath1 + 27@xmath0 27 & 033 & 250 & @xmath1 + 27@xmath0 27 & 067 & 700 , 2500 & @xmath2 + 13@xmath0 13 & 033 & 700 , 2500 & @xmath2 + ifu data reduction presents new challenges and requires to set up new data reduction techniques with respect to `` traditional '' mos data . two main aspects that have to be taken into account for the data reduction of every ifu are the high density of spectra on the detector , causing some degree of crosstalk ( overlapping of light from neighbouring spectra ) and the sky subtraction , demanding special care , since the sky must be evaluated using different fibers for different observations . for vimos ifu in particular a third aspect is the high number of spectra collected in a single exposure ( up to 6400 spectra on four 2k@xmath04k ccds ) , requiring at least a partial automatization of the reduction process . once data have been reduced , exploiting their scientific content is even more challenging . for this reason a european network has been set up , formed by all the european institutes involved in ifu instrument development , with the purpose to provide the european astronomical community with powerful 3d data analysis tools . the fact that an ifu can obtain spectra for all the objects in the field of view at once makes it much more efficient than a mos in very crowded field , where complete sampling is required . this is especially true in the case of high - z clusters , where the numbers of interlopers is roughly 90% of all the field objects . this can have great advantages regarding spectroscopic confirmation of clusters and dynamical studies of cluster cores , where just one ifu observation ( or a few ones , if using the smaller size and higher resolution configuration ) could obtain the same result as several mos exposures . it is clear that medium and high - z clusters , being of a smaller angular size , are ideal targets for ifu observations , as shown by figure 1 .
Abstract: | [
"research on the core of medium and high z clusters of galaxies can derive great benefits from integral field spectroscopy , and a key role in this respect will be played by the integral field unit ( ifu ) being developed by the virmos consortium as part of the vimos spectrograph . after a brief technical outline of the instrument , some of the problems to be addressed by data reduction techniques are described , and the scientific issues to which vimos ifu is likely to give its major contribution are pointed out ."
] | 555 | 555 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: after the completion of the palomar - quest northern sky survey in september 2008 the quest large field camera ( ( * ? ? ? * baltay et al . 2007 ) ) was moved and installed on the 1.0-m eso schmidt in la silla and had first light on april 24 , 2009 . since september 2009 , the southern survey has been in routine observations ( ( * ? ? ? * andrews et al . 2008 ) ) and the telescope and camera are controlled from yale and fully robotic . we have 90@xmath1 of the time on the telescope with 10@xmath1 allocated to chile . the quest camera consists of 112 ccds of 600 @xmath2 2400 sarnoff thinned pixels , back illuminated devices with 13 @xmath3 m x 13 @xmath3 m pixel pitch . the camera covers an area of 4.6@xmath4 @xmath2 3.6@xmath4 on the sky and a plate scale of 0.86 arcsec / pixel . the survey covers @xmath51000 square degrees per night , primarily between @xmath625@xmath4 to allow for follow up from both hemispheres . the lsq variability ( sn and transient ) survey uses 60 sec exposures ( and the tno survey-180 sec ) taken twice a night with a cadence of 2 nights in one broad band filter of 4000 to 7000 ( qst*-band ) . the seeing at la silla for the 60 sec exposures is 1.7 arcsec fwhm , reaching depth of 20.5 mag . the lsq survey subtraction pipeline has started producing between 400 and 900 transient candidates each night ( fig.[fig3 ] ) . the lsq rr lyrae star ( rrls ) survey is searching the galactic halo for rrls that have v magnitudes between roughly 14 and 20 . because rrls are excellent standard candles , they provide a powerful probe of the density distribution of the halo , which is being examined for halo substructure . plotted are the v magnitude light - curves for three type ab rrls ( fig.[fig5](a ) ) , which illustrate the typical photometric precisions at these magnitudes . from their mean v magnitudes , we estimate that rrab 12574 , 10770 , and 5381 lie 7 , 13 , and 52 kpc from the sun , respectively . a deep eclipsing cataclysmic variable ( ( * ? ? ? * rabinowitz et al . 2011a ) ) was discovered with eclipse depths @xmath75.7 magnitudes , orbital period 94.657 min , and peak brightness v@xmath518 at j2000 position 17h 25 m 54.8s , -64 deg 38 min 39 sec . light curves in b , v , r , i , z and j were obtained with smarts 1.3-m and 1.0-m telescopes at cerro tololo and spectra from 3500 to 9000 with the soar 4.3-m telescope at cerro pachon . the optical light curves ( fig.[fig5](b ) ) show a deep , 5-min eclipse immediately followed by a shallow 38-min eclipse and then sinusoidal variation . no eclipses appear in j. during the deep eclipse the measure of v - j @xmath7 7.1 corresponds to a spectral type m8 or later secondary . the spectra show strong hydrogen emission lines , doppler broadened by 600 - 1300 km s-1 , oscillating with radial velocity that peaks at mid deep eclipse with semiamplitude 500 @xmath6 22 km s-1 . it is suggested that lsq172554.8 - 643839 is a polar with a low - mass secondary viewed at high inclination . an apparent dwarf nova was discovered ( ( * ? ? ? * rabinowitz et al . 2011b ) ) on june 11.046 ( when the variable was at magnitude r = 16.3 ) and june 11.063 ut ( at r = 16.0)(fig.[fig6](a ) and ( b ) ) . a faint source is reported at this position in the guide star catalog v2.3.2 ( with bj = 20.76 ) . simultaneous visible and j - band observations were taken with andicam on the 1.3-m smarts telescope at cerro tololo . a spectrum ( range 0.350 - 0.966 nm ) taken on june 26 with gmos on the gemini south telescope reveals strong h - alpha and h - beta emission lines , with h - alpha clearly double - peaked , indicating the presence of an accretion disk with rotational velocity 1000 km / s .
Abstract: | [
"we describe the la silla - quest ( lsq ) variability survey . lsq is a dedicated wide field synoptic survey in the southern hemisphere , focusing on the discovery and study of transients ranging from low redshift ( z @xmath0 0.1 ) sn ia , tidal disruption events , rr lyrae variables , cvs , quasars , tnos and others . the survey utilizes the 1.0-m schmidt telescope of the european southern observatory at la silla , chile with the large area quest camera , a mosaic of 112 ccd s with field of view of 9.6 square degrees . the lsq survey was commissioned in 2009 , and is now regularly covering 1000 square deg per night with a repeat cadence of hours to days . the data are currently processed on a daily basis . we present here a first look at the photometric capabilities of lsq and we discuss some of the most interesting recent transient detections ."
] | 814 | 814 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: compact groups of galaxies are associations of three to seven galaxies , where the projected distances between them is of the order of their diameters , and where the group shows a low velocity dispersion , making compact groups an ideal place to study galaxy interaction and intergalactic star formation ( e.g. ( * ? ? ? * torres - flores et al . 2010 ) , ( * ? ? ? * de mello et al . 2008 ) , ( * ? ? ? * de mello , torres flores & mendes de oliveira 2008 ) , ( * ? ? ? * mendes de oliveira et al . 2004 ) ) . the main goal of this work is to search for a link between the evolutionary stage of a group and the presence of young intergalactic objects which may have formed during galaxy interactions . for this , we analyze a subsample of seven compact groups ( hcg 2 , 7 , 22 , 23 , 92 , 100 and ngc 92 ) which span a wide range of evolutionary stages , from hi rich groups to strongly interacting groups , where the galaxies show tidal tail features and a deficiency in neutral hi gas . in order to analyze the evolutionary stage of each group , we used new fabry - perot velocity maps , galex / uv data and optical r - band images . the velocity fields and rotation curves help constraining the evolutionary stage of each compact group while ultraviolet light contains important information regarding the age of the young stellar population that may be present in the intragroup medium . we searched for ultraviolet emitting regions in the vicinity of all seven targets , using the sextractor software ( se , ( * ? ? ? * bertin & arnouts 1996 ) ) in the fuv , nuv and r sky - subtracted images of our compact group sample . we compare the field density of regions detected in the compact group with a control sample outside the group . hcg 92 and hcg 22 have the highest field density in this study . no excess was found in hcg 2 , hcg 7 , hcg 23 , hcg 100 and ngc 92 ( ( * ? ? ? * torres - flores et al . 2009 ) ) . in order to constrain the evolutionary stage of each compact group , we inspected the velocity field and rotation curve of each galaxy to search for interaction indicators , in a similar way to that done by ( * ? ? ? * plana et al . ( 2003 ) ) and ( * ? ? ? * amram et al . ( 2003 ) ) . in the case of ngc 92 , it shows a prominent tidal tail in its velocity field . at the tip of this tail , there is a tidal dwarf galaxy candidate , having an age of about 40 myrs ( ( * ? ? ? * torres - flores et al . 2009 ) ) . we used multiwavelength data to study the evolutionary stages of the compact groups of galaxies hcg 2 , 7 , 22 , 23 , 92 , 100 and ngc 92 . new fabry - perot velocity fields , rotation curves and galex nuv / fuv images were analyzed for four and seven of these groups respectively . groups hcg 7 and 23 are in an early stage of interaction whereas hcg 2 and 22 show limited interaction features and hcg 92 , 100 and ngc 92 are in a late stage of evolution , having hi gas in the intragroup medium , galaxies with peculiar velocity fields and several young star - forming regions in the intergalactic medium .
Abstract: | [
"we present the results of a multiwavelength campaign searching for young objects in the intragroup medium of seven compact groups of galaxies : hcg 2 , 7 , 22 , 23 , 92 , 100 and ngc 92 . we used fabry - perot velocity fields and rotation curves together with galex nuv and fuv images , optical r - band and hi maps to evaluate the stage of interaction of each group . we conclude that groups ( i ) hcg 7 and hcg 23 are in an early stage of interaction , ( ii ) hcg 2 and hcg 22 are mildly interacting , and ( iii ) hcg 92 , hcg 100 and ngc 92 are in a late stage of evolution . evolved groups have a population of young objects in their intragroup medium while no such population is found within the less evolved groups . we also report the discovery of a tidal dwarf galaxy candidate in the tail of ngc 92 . these three groups , besides containing galaxies which have peculiar velocity fields , also show extended hi tails . our results indicate that the advanced stage of evolution of a group together with the presence of intragroup hi clouds may lead to star formation in the intragroup medium ."
] | 731 | 731 | 1,000 |
Write an abstract for the following acadamic paper. | Paper: we have recorded the flight of a fly during take off and landing using digital high speed photography . it is shown that the dynamics of flexible wings are different for these procedures . during this observation fly flew freely in a big box and it was not tethered .
Abstract: in this fluid dynamics video , we demonstrated take off and landing of a fly . the deformation of wings is in focus in this video .
Paper: we present the characteristics and performances of a demonstrative experiment devoted to the observation of ultra high- energy cosmic rays extensive air showers using a radiodetection technique . the codalema ( cosmic ray detection array with logarithmic electromagnetic antennas ) experiment was set up at the nanay radio observatory in 2003 . it uses 6 of the 144 log - periodic antennas ( in the 1 - 100 mhz frequency band for codalema ) constituting the decametric array ( dam ) @xcite . in the first period of observation @xcite , the setup ( see fig . [ fig : setup ] ) was self - triggered using one devoted antenna : its signal was filtered in an appropriate noise - free frequency band ( 33 - 65 mhz ) chosen after an exhaustive study in the observed local noise frequency spectrum , before entering the adc . the wide band waveform signals ( 1 - 100 mhz ) of the other antennas were registered when a voltage threshold was reached on the trigger antenna . the trigger threshold was set at 4 @xmath1 ( @xmath1 : the rms sky background noise ) , leading to an electric field sensitivity of 4 @xmath2v / m . on figure [ fig : triggerlevel ] the evolution of the average counting rate at nancay is presented as a function of the trigger level expressed in unit of @xmath1 . the counting rate evolves greatly with the anthropic activities in the vicinity of the station of nancay and with the weather conditions . except for the trigger antenna , transient signals on the antennas were hidden by radio transmitters signals . consequently , a numerical passband filter ( same as trigger frequency band ) was applied , offline , in order to observe coincidences involving several antennas @xcite . using the position and the timing differences between antennas , it was also possible to perform the trajectory reconstruction of the electromagnetic plane wave using a triangulation techniques across the array @xcite . this level of analysis enables us to bring in light several cosmic ray air shower candidates . in the second phase operating since mid 2004 , the above setup ( see fig . [ fig : setup2 ] ) has been completed with four double plastic scintillators @xcite placed at the corner of the dam array ( @xmath3 ) . the trigger of the experiment is made of the four particle detectors in coincidence , resulting on an event rate of 0.8 event / mn . all the antennas have now the same role and are passband filtered ( 24 - 82 mhz ) in order to increase the signal to noise ratio . the observation of coincident events on antennas and charged particle detectors ( fig . [ fig : r248e1782 ] ) demonstrates the association of antenna transient signals with the occurrence of extensive air showers . this unambiguous evidence of radio signals through the simultaneous detection of shower particles will allow , for the first time , the characterisation of the shape and amplitude of air showers associated radio pulses . a preliminary event rate of 1/(8 hours ) is observed with antenna multiplicity ranging from 3 to 6 . from the corresponding deposited energy distribution in scintillators , one can infer the location of the air shower core . the time delays between the particle detectors allow the reconstruction of the shower axis . from these information , impact parameter effects can be studied especially those related to non vertical showers . the latter are expected @xcite to generate amplitude and shape field variations which will better show up in large atmosphere volumes accessible with radiodetection method . purposely , 5 antennas will be installed ( up to 400 m from the dam ) on a east - west line crossing the existing array . two effects , namely cerenkov emission and the classical far field , contribute to the radio emission of a shower @xcite . the line will also allow to study their respective influences and asseses the interest for designing a larger antenna array dedicated to ultra high energy cosmic rays . http://www.obs-nancay.fr/ and http://www - subatech.in2p3.fr/. ravel o. _ et al . * a518 * , 213 - 215 ( 2004 ) . dallier r. _ et al . sf2a 2003 scientific highlights _ , ed f. combes _ et al . _ ( edp sciences , 2003 ) . a. belltoile _ et al . _ , astro - ph/0409034 ( 2004 ) . m. boratav _ et al _ , _ proc . of the @xmath4icrc _ , rome , 954,(1984 ) . t. gousset , o. ravel and c. roy , _ astroparticle physics _ , * 22 * , 103 - 107 ( 2004 ) .
Abstract: | [
"the codalema experiment uses 6 large frequency bandwidth antennas of the nanay radio observatory decametric array ( france ) . in a first configuration , one antenna narrowed band filtered acting as trigger , with a 4 @xmath0 threshold above sky background - level , was used to tag any radio transient in coincidence on the antenna array . recently , the addition of 4 particle detectors allowed us to observe cosmic ray events in coincidence with antennas . * keywords:*ultra high energy cosmic rays ; radiodetection ."
] | 896 | 896 | 1,000 |
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Introduction
M4LE is a Multi-ability, Multi-range, Multi-task, bilingual benchmark for long-context evaluation. We categorize long-context understanding into five distinct abilities by considering whether it is required to identify single or multiple spans in long contexts based on explicit or semantic hints. Specifically, these abilities are explicit single-span, semantic single-span, explicit multiple-span, semantic multiple-span, and global. Different from previous long-context benchmarks that simply compile from a set of existing long NLP benchmarks, we introduce an automated method to transform short-sequence tasks into a comprehensive long-sequence scenario encompassing all these capabilities.
M4LE consists of 36 tasks, covering 11 task types and 12 domains. For each task, we construct 200 instances for each context length bucket (1K, 2K, 4K, 6K, 8K, 12K, 16K, 24K, 32K, 64K, 128K). Due to computation and cost constraints, our paper evaluated 11 well-established LLMs on instances up to the 8K context length bucket. For more details, please refer to the paper available at https://arxiv.org/abs/2310.19240. You can also explore the GitHub page at https://github.com/KwanWaiChung/M4LE.
Usage
You can load the dataset by specifying the task name:
from datasets import load_dataset
tasks = [
"arxiv",
"bigpatent_global_cls",
"bigpatent_global_sum",
"booksum",
"c3",
"cepsum",
"clts+",
"cnewsum",
"cnnnews",
"drcd_explicit-single",
"drcd_semantic-single",
"duorc",
"dureader",
"hotpotqa",
"lcsts",
"marc",
"mnds-news_explicit-single",
"mnds-news_explicit-multiple",
"mnds-news_semantic-multiple",
"ncls",
"news-commentary-en2zh",
"news-commentary-zh2en",
"news2016",
"newsqa",
"nq-open",
"online-shopping",
"open-subtitles-en2zh",
"open-subtitles-zh2en",
"pubmed",
"tedtalks-en2zh",
"tedtalks-zh2en",
"thucnews_explicit-single",
"thucnews_explicit-multiple",
"thucnews_semantic-multiple",
"triviaqa",
"wiki2019zh",
"wikihow",
"wikitext-103",
"wow",
]
for task in tasks:
data = load_dataset('wckwan/M4LE', task, split='test')
Format
Each testing instance follows this format:
{
"instruction": "<task description>",
"input": "<task input with one-shot example>",
"answers": ["<answer1>", "<answer2>"],
"input_length": <int, number of words in instruction and input separated by space>,
"total_length": <int, number of words in instruction, input and gold answer separated by space>,
"length_bucket": <int, the length bucket to which this instance belongs>
}
Tasks
Here is the full list of the tasks with their descriptions. For more details about these tasks, please refer to the paper.
| Ability | Task Name | Task Type | Language | Description |
|---|---|---|---|---|
| Explicit Single | mnds-news_explicit-single | CLS + RET | En | Classify a specified news article. |
| Explicit Single | thucnews_explicit-single | CLS + RET | Zh | Classify a specified news article. |
| Explicit Single | newsqa | QA + RET | En | Answer a question based on a specified news article. |
| Explicit Single | c3 | QA + RET | Zh | Answer a multi-choice question based on a textbook extract. |
| Explicit Single | wow | RET | En | Return the ID of the article related to a specified topic. |
| Explicit Single | drcd_explicit-single | RET | Zh | Return the ID of the article related to a specified topic. |
| Explicit Single | cnnnews | SUM + RET | En | Summarize a specified news article. |
| Explicit Single | cepsum | SUM + RET | Zh | Summarize a specified product description. |
| Explicit Single | lcsts | SUM + RET | Zh | Summarize a specified news article. |
| Explicit Single | ncls | SUM + RET | En, Zh | Summarize a specified news article. |
| Explicit Multiple | mnds-news_explicit-multiple | CLS + RET | En | Return the IDs of all the articles belong to a specified class. |
| Explicit Multiple | thucnews_explicit-multiple | CLS + RET | Zh | Return the IDs of all the articles belong to a specified class. |
| Explicit Multiple | marc | CLS + RET | En, Zh | Return the IDs of all the positive product reviews. |
| Explicit Multiple | online-shopping | CLS + RET | Zh | Return the IDs of all the positive product reviews. |
| Semantic Single | wikitext-103 | NLI + RET | En | Return the ID of the paragraph that continues a query paragraph. |
| Semantic Single | wiki2019zh | NLI + RET | Zh | Return the ID of the paragraph that continues a query paragraph. |
| Semantic Single | duorc | QA | En | Answer a question based on multiple movie plots. |
| Semantic Single | nq-open | QA | En | Answer a question based on multiple wikipedia paragraphs. |
| Semantic Single | dureader | QA | Zh | Answer a question based on multiple web snippets. |
| Semantic Single | drcd_semantic-single | QA | Zh | Answer a question based on multiple wikipedia paragraphs. |
| Semantic Single | wikihow | SUM + RET | En | Summarize an article based on a given topic. |
| Semantic Single | news2016 | SUM + RET | Zh | Summarize a news article based on a given title. |
| Semantic Single | tedtalks-en2zh/tedtalks-zh2en | TRAN + RET | En, Zh | Translate a Ted Talk transcript based on a given title. |
| Semantic Multiple | mnds-news_semantic-multiple | CLS + CNT | En | Return the number of news articles belonging to a specified class. |
| Semantic Multiple | thucnews_semantic-multiple | CLS + CNT | Zh | Return the number of news articles belonging to a specified class. |
| Semantic Multiple | hotpotqa | QA | En | Answer a question based on multiple wikipedia paragraphs. |
| Global | bigpatent_global_cls | CLS | En | Classify a patent document. |
| Global | triviaqa | QA | En | Answer a question based on a web snippet. |
| Global | arxiv | SUM | En | Summarize an academic paper. |
| Global | bigpatent_global_sum | SUM | En | Summarize a patent document. |
| Global | pubmed | SUM | En | Summarize a medical paper. |
| Global | booksum | SUM | En | Summarize one or more chapters of a book. |
| Global | cnewsum | SUM | Zh | Summarize a news article. |
| Global | clts+ | SUM | Zh | Summarize a news article. |
| Global | open-subtitles-en2zh/open-subtitles-zh2en | TRAN | En, Zh | Translate the movie subtitles. |
| Global | news-commentary-en2zh/news-commentary-zh2en | TRAN | En, Zh | Translate the movie subtitles. |
Citation
If you find our paper and resources useful, please consider citing our paper:
@misc{kwan_m4le_2023,
title = {{{M4LE}}: {{A Multi-Ability Multi-Range Multi-Task Multi-Domain Long-Context Evaluation Benchmark}} for {{Large Language Models}}},
author = {Kwan, Wai-Chung and Zeng, Xingshan and Wang, Yufei and Sun, Yusen and Li, Liangyou and Shang, Lifeng and Liu, Qun and Wong, Kam-Fai},
year = {2023},
}
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