374 research outputs found
Are Italian research assessment exercises size-biased?
Research assessment exercises have enjoyed ever-increasing popularity in many countries in recent years, both as a method to guide public funds allocation and as a validation tool for adopted research support policies. Italyâs most recently completed evaluation effort (VQR 2011â14) required each university to submit to the Ministry for Education, University, and Research (MIUR) 2 research products per author (3 in the case of other research institutions), chosen in such a way that the same product is not assigned to two authors belonging to the same institution. This constraint suggests that larger institutions, where collaborations among colleagues may be more frequent, could suffer a size-related bias in their evaluation scores. To validate our claim, we investigate the outcome of artificially splitting Sapienza University of Rome, one of the largest universities in Europe, in a number of separate partitions, according to several criteria, noting significant score increases for several partitioning scenarios
Which Conference Is That? A Case Study in Computer Science
Conferences play a major role in some disciplines such as computer science and are often used in research quality evaluation exercises. Differently from journals and books, for which ISSN and ISBN codes provide unambiguous keys, recognizing the conference series in which a paper was published is a rather complex endeavor: There is no unique code assigned to conferences, and the way their names are written may greatly vary across years and catalogs. In this article, we propose a technique for the entity resolution of conferences based on the analysis of different semantic parts of their names. We present the results of an investigation of our technique on a dataset of 42,395 distinct computer science conference names excerpted from the DBLP computer science repository,1 which we automatically link to different authority files. With suitable data cleaning, the precision of our record linkage algorithm can be as high as 94%. A comparison with results obtainable using state-of-the-art general-purpose record linkage algorithms rounds off the article, showing that our ad hoc solution largely outperforms them in terms of the quality of the results
Detecting contour crossings in contour dynamical and contour-advective semi-Lagrangian simulations
Contour dynamics and contour-advective methods are commonly used numerical techniques for simulating inviscid fluid motions. In these methods the vorticity or potential vorticity of a flow is represented by a series of contours which are advected according to the prevailing velocity field. In some circumstances the contours may cross, eroding the accuracy of the numerical solution and violating the equations of motion. This paper describes an automated method for explicitly revealing such crossings, first considering the case of determining if two contours cross and then later the more general case of determining if and where an arbitrary number of contours cross
Honeybee linguisticsĂąâŹâa comparative analysis of the waggle dance among species of Apis
All honeybees use the waggle dance to recruit nestmates. Studies on the dance precision of Apis mellifera have shown that the dance is often imprecise. Two hypotheses have been put forward aimed at explaining this imprecision. The first argues that imprecision in the context of foraging is adaptive as it ensures that the dance advertises the same patch size irrespective of distance. The second argues that the bees are constrained in their ability to be more precise, especially when the source is nearby. Recent studies have found support for the latter hypothesis but not for the âtuned-errorâ hypothesis, as the adaptive hypothesis became known. Here we investigate intra-dance variation among Apis species. We analyse the dance precision of A. florea, A. dorsata, and A. mellifera in the context of foraging and swarming. A. mellifera performs forage dances in the dark, using gravity as point of reference, and in the light when dancing for nest sites, using the sun as point of reference. Both A. dorsata and A. florea are open-nesting species; they do not use a different point of reference depending on context. A. florea differs from both A. mellifera and A. dorsata in that it dances on a horizontal surface and does not use gravity but instead âpointsâ directly toward the goal when indicating direction. Previous work on A. mellifera has suggested that differences in dance orientation and point of reference can affect dance precision. We find that all three species improve dance precision with increasing waggle phase duration, irrespective of differences in dance orientation, and point of reference. When dancing for sources nearby, dances are highly variable. When the distance increases, dance precision converges. The exception is dances performed by A. mellifera on swarms. Here, dance precision decreases as the distance increases. We also show that the size of the patch advertised increases with increasing distance, contrary to what is predicted under the tuned-error hypothesis
Polarization Asymmetry In The Photodisintegration Of The Deuteron
The reaction ÂČ(Îł,p)n has been studied using a monochromatic and polarized gamma ray beam at energies E(Îł)=19.8, 29.0, 38.6, and 60.8 MeV. The beam of an intensity âŒ4Ă10â” Îł/sec was obtained by Compton back scattering of mode-locked laser light off electron bunches in the Adone storage ring. Photoneutron yields were measured at nine neutron angles thetanâ15, 30, 45, 60, 90, 120, 135, 150, and 165 deg in the center of mass (c.m.) for E(Îł)=19.8, 29.0, and 38.6 MeV, and at thetanâ30, 60, 90, 120, and 150 deg c.m. for E(Îł)=60.8 MeV. The polarization independent component Iâ(theta) of the differential cross section and the polarization dependent component PIâ(theta) were deduced and the angular distribution of the azimuthal asymmetry factor ÎŁ(theta)=Iâ(theta)/Iâ(theta) was obtained. An extensive comparison with theory has been carried out and the inclusion of corrections due to meson exchange currents and to Î-isobar configurations have been shown to be mandatory at energies E(Îł)âł40 MeV. Theoretical and experimental implications of intermediate energy deuteron photo- disintegration studies are discussed in some detail
Polarization Asymmetry In The Photodisintegration Of The Deuteron
The reaction ÂČ(Îł,p)n has been studied using a monochromatic and polarized gamma ray beam at energies E(Îł)=19.8, 29.0, 38.6, and 60.8 MeV. The beam of an intensity âŒ4Ă10â” Îł/sec was obtained by Compton back scattering of mode-locked laser light off electron bunches in the Adone storage ring. Photoneutron yields were measured at nine neutron angles thetanâ15, 30, 45, 60, 90, 120, 135, 150, and 165 deg in the center of mass (c.m.) for E(Îł)=19.8, 29.0, and 38.6 MeV, and at thetanâ30, 60, 90, 120, and 150 deg c.m. for E(Îł)=60.8 MeV. The polarization independent component Iâ(theta) of the differential cross section and the polarization dependent component PIâ(theta) were deduced and the angular distribution of the azimuthal asymmetry factor ÎŁ(theta)=Iâ(theta)/Iâ(theta) was obtained. An extensive comparison with theory has been carried out and the inclusion of corrections due to meson exchange currents and to Î-isobar configurations have been shown to be mandatory at energies E(Îł)âł40 MeV. Theoretical and experimental implications of intermediate energy deuteron photo- disintegration studies are discussed in some detail
Existence of Monetary Steady States in a Matching Model: Indivisible Money
Existence of a monetary steady state is established for a random matching model with divisible goods, indivisible money, and take-it-or-leave-it offers by consumers. There is no restriction on individual money holdings. The background environment is that in papers by Shi and by Trejos and Wright. The monetary steady state shown to exist has nice properties: the value function, defined on money holdings, is increasing and strictly concave, and the measure over money holdings has full support.
The GRAAL high resolution BGO calorimeter and its energy calibration and monitoring system
We describe the electromagnetic calorimeter built for the GRAAL apparatus at
the ESRF. Its monitoring system is presented in detail. Results from tests and
the performance obtained during the first GRAAL experiments are given. The
energy calibration accuracy and stability reached is a small fraction of the
intrinsic detector resolution.Comment: 19 pages, 14 figures, submitted to Nuclear Instruments and Method
Deuteron photo-disintegration with polarised photons in the energy range 30 - 50 MeV
The reaction d(\vec\gamma,np) has been studied using the tagged and polarised
LADON gamma ray beam at an energy 30 - 50 MeV to investigate the existence of
narrow dibaryonic resonances recently suggested from the experimental
measurements in a different laboratory. The beam was obtained by Compton
back-scattering of laser light on the electrons of the storage ring ADONE.
Photo-neutron yields were measured at five neutron angle \vartheta_n = 22,
55.5, 90, 125 and 157 degrees in the center of mass system.Our results do not
support the existence of such resonances.Comment: 16 pages, Latex, 22 figures, 1 table. Nucl. Phys. A to appea
Eta photoproduction off the neutron at GRAAL: Evidence for a resonant structure at W=1.67 GeV
New (preliminary) data on eta photoproduction off the neutron are presented.
These data reveal a resonant structure at W=1.67 GeV.Comment: 8 pages, 4 figures. Published in Proceedings of Workshop on the
Physics of Excited Nucleons NSTAR2004, Grenoble, France, March 24 - 27,
pg.19
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