1,947 research outputs found

    Motives and comprehension in a public goods game with induced emotions

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    This study analyses the sensitivity of public goods contributions through the lens of psychological motives. We report the results of a public goods experiment in which subjects were induced with the motives of care and anger through autobiographical recall. Subjects’ preferences, beliefs, and perceptions under each motive are compared with those of subjects experiencing a neutral autobiographical recall control condition. We find, but only for those subjects with the highest comprehension of the game, that care elicits significantly higher contributions than anger, with the control treatment in between. This positive influence of the care motive on unconditional giving is accounted for partly by preferences for giving and partly by beliefs concerning greater contributions by others. Anger also affects attention to own and other’s payoffs (measured by mouse tracking) and perceptions of the game’s incentive structure (cooperative or competitive)

    Hadronic centrality dependence in nuclear collisions

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    The kaon number density in nucleus+nucleus and p+p reactions is investigated for the first time as a function of the initial energy density ϵ\epsilon and is found to exhibit a discontinuity around ϵ\epsilon=1.3 GeV/fm3^3. This suggests a higher degree of chemical equilibrium for ϵ>\epsilon > 1.3 GeV/fm3^3. It can also be interpreted as reflection of the same discontinuity, appearing in the chemical freeze out temperature (T) as a function of ϵ\epsilon. The Nα1N^{\alpha \sim 1} dependence of (u,d,s) hadrons, whith N the number of participating nucleons, also indicates a high degree of chemical equilibrium and T saturation, reached at ϵ>\epsilon >1.3 GeV/fm3^3. Assuming that the intermediate mass region (IMR) dimuon enhancement seen by NA50 is due to open charm (DDˉD \bar{D}), the following observation can be made: a) Charm is not equilibrated. b) J/Ψ/DDˉJ/\Psi/D \bar{D} suppression -unlike J/Ψ/DYJ/\Psi/DY- appears also in S+A collisions, above ϵ\epsilon \sim1 GeV/fm3^3. c) Both charm and strangeness show a discontinuity near the same ϵ\epsilon. d) J/ΨJ/\Psi could be formed mainly through ccˉc \bar{c} coalescence. e) The enhancement factors of hadrons with u,d,s,c quarks may be connected in a simple way to the mass gain of these particles if they are produced out of a quark gluon plasma (QGP). We discuss these results as possible evidence for the QCD phase transition occuring near ϵ\epsilon \sim 1.3 GeV/fm3^3.Comment: 4 pages, 4 figures, proceedings of Vth International Conference on Strangeness in Quark Matter, 20-25 July 2000, Berkeley, California. To appear in Journal of Physics G: Nuclear and Particle Physic

    Particle abundances and spectra in the hydrodynamical description of relativistic nuclear collisions with light projectiles

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    We show that a hydrodynamical model with continuous particle emission instead of sudden freeze out may explain both the observed strange particle and pion abundances and transverse mass spectra for light projectile at SPS energy. We found that the observed enhancement of pion production corresponds, within the context of continuous emission, to the maximal entropy production.Comment: 11 pages, 2 figure

    Formation of Centauro and Strangelets in Nucleus-Nucleus Collisions at the LHC and their Identification by the ALICE Experiment

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    We present a phenomenological model which describes the formation of a Centauro fireball in nucleus-nucleus interactions in the upper atmosphere and at the LHC, and its decay to non-strange baryons and Strangelets. We describe the CASTOR detector for the ALICE experiment at the LHC. CASTOR will probe, in an event-by-event mode, the very forward, baryon-rich phase space 5.6 < \eta < 7.2 in 5.5 A TeV central Pb + Pb collisions. We present results of simulations for the response of the CASTOR calorimeter, and in particular to the traversal of Strangelets.Comment: 4 pages, 4 figures, to appear in the proceedings of the 26th ICR

    CASTOR: Centauro and Strange Object Research in nucleus-nucleus collisions at LHC

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    We describe the CASTOR detector designed to probe the very forward, baryon-rich rapidity region in nucleus-nucleus collisions at the LHC. We present a phenomenological model describing the formation of a QGP fireball in a high baryochemical potential environment, and its subsequent decay into baryons and strangelets. The model explains Centauros and the long-penetrating component and makes predictions for the LHC. Simulations of Centauro-type events were done. To study the response of the apparatus to new effects different exotic species (DCC, Centauros, strangelets etc.) were passed through the deep calorimeter. The energy deposition pattern in the calorimeter appears to be a new clear signature of the QGP.Comment: Talk given by E. Gladysz-Dziadus for the CASTOR group, Intern. Workshop on Nuclear Theory, 10-15 June, 2002, Bulgaria, Rila Mountains, 15 pages, 14 figure

    Local orientational order in the Stockmayer liquid

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    Phase behaviour of the Stockmayer fluid is studied with a method similar to the Monte-Carlo annealing scheme. We introduce a novel order parameter which is sensitive to the local co-orientation of the dipoles of particles in the fluid. We exhibit a phase diagram based on the behaviour of the order parameter in the density region 0.1 \leq {\rho}\ast \leq 0.32. Specifically, we observe and analyse a second order locally disordered fluid \rightarrow locally oriented fluid phase transition.Comment: 13 pages, 7 figure

    Characterization of ovarian follicle reserve depletion in Ames dwarf mice.

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    Publicado: Proceedings of the 29th Annual Meeting of the Brazilian Embryo Technology Society (SBTE); Gramado, RS, Brazil, August 20th to 23rd, 2015, and 31st Meeting of the European Embryo Transfer Association (AETE); Ghent, Belgium, September 11th and 12th, 2015. Abstracts

    Production of deuterium, tritium, and 3^3He in central Pb+Pb collisions at 20A, 30A, 40A, 80A, and 158A GeV at the CERN SPS

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    Production of dd, tt, and 3^3He nuclei in central Pb+Pb interactions was studied at five collision energies (sNN=\sqrt{s_{NN}}= 6.3, 7.6, 8.8, 12.3, and 17.3 GeV) with the NA49 detector at the CERN SPS. Transverse momentum spectra, rapidity distributions, and particle ratios were measured. Yields are compared to predictions of statistical models. Phase-space distributions of light nuclei are discussed and compared to those of protons in the context of a coalescence approach. The coalescence parameters B2B_2 and B3B_3, as well as coalescence radii for dd and 3^3He were determined as a function of transverse mass at all energies.Comment: 22 pages, 29 figures, 8 tables, for submission to Phys. Rev.

    Phase-space dependence of particle-ratio fluctuations in Pb+Pb collisions from 20A to 158A GeV beam energy

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    A novel approach, the identity method, was used for particle identification and the study of fluctuations of particle yield ratios in Pb+Pb collisions at the CERN Super Proton Synchrotron (SPS). This procedure allows to unfold the moments of the unknown multiplicity distributions of protons (p), kaons (K), pions (π\pi) and electrons (e). Using these moments the excitation function of the fluctuation measure νdyn\nu_{\text{\text{dyn}}}[A,B] was measured, with A and B denoting different particle types. The obtained energy dependence of νdyn\nu_{\text{dyn}} agrees with previously published NA49 results on the related measure σdyn\sigma_{\text{dyn}}. Moreover, νdyn\nu_{\text{dyn}} was found to depend on the phase space coverage for [K,p] and [K,π\pi] pairs. This feature most likely explains the reported differences between measurements of NA49 and those of STAR in central Au+Au collisions
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