12,273 research outputs found

    Seismic diagnostics for transport of angular momentum in stars 2. Interpreting observed rotational splittings of slowly-rotating red giant stars

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    Asteroseismology with the space-borne missions CoRoT and Kepler provides a powerful mean of testing the modeling of transport processes in stars. Rotational splittings are currently measured for a large number of red giant stars and can provide stringent constraints on the rotation profiles. The aim of this paper is to obtain a theoretical framework for understanding the properties of the observed rotational splittings of red giant stars with slowly rotating cores. This allows us to establish appropriate seismic diagnostics for rotation of these evolved stars. Rotational splittings for stochastically excited dipolar modes are computed adopting a first-order perturbative approach for two 1.3M⊙1.3 M_\odot benchmark models assuming slowly rotating cores. For red giant stars with slowly rotating cores, we show that the variation of the rotational splittings of ℓ=1\ell=1 modes with frequency depends only on the large frequency separation, the g-mode period spacing, and the ratio of the average envelope to core rotation rates (R{\cal R}). This leds us to propose a way to infer directly R{\cal R} from the observations. This method is validated using the Kepler red giant star KIC 5356201. Finally, we provide a theoretical support for the use of a Lorentzian profile to measure the observed splittings for red giant stars.Comment: 15 pages, 15 figures, accepted for publication in A&

    O mini-cavalo (Equus caballus) puruca da ilha de MarajĂł - Brasil.

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    O mini-cavalo Puruca em conservação no BAGAM - Banco de Germoplasma Animal da AmazĂŽnia Oriental constitui uma pequena população, sendo resultado do cruzamento do cavalo Marajoara com o pĂŽnei da raça francesa ?Shetland?, que foi selecionado atĂ© atingir a altura padrĂŁo de 1,18m. A Associação Brasileira de Criadores da Raça Puruca ? ABCRP cita que a raça possui inĂșmeras caracterĂ­sticas morfolĂłgicas que o tornam um grupo diferenciado. Os animais sĂŁo criados em Salvaterra, ilha de MarajĂł, PA. Os descritores estudados sĂŁo: Altura da Cernelha (AC), Altura do Dorso (AD), Altura da Garupa (AG), Altura de Costados (ACo), Comprimento da Cabeça (CCa), Comprimento do Pescoço (CP), Comprimento Dorso-Lombo (CDL), Comprimento da Garupa (CG), Comprimento da EspĂĄdua (CE), Comprimento do Corpo (CC), Largura da Cabeça (LC), Largura do Peito (LP), Largura das Ancas (LA), PerĂ­metro do TĂłrax (PT) e PerĂ­metro da Canela (PC), alĂ©m dos pesos nas idades padrĂ”es. A raça, com base em marcadores microssatĂ©lites, Ă© uma variedade da raça Marajoara, em função de cruzamentos entre os dois grupos genĂ©ticos e seleção para o menor porte. Este trabalho apresenta resultados parciais dos principais descritores, alĂ©m de avaliar o comportamento e o desempenho da raça em conservação

    Interaction-induced topological properties of two bosons in flat-band systems

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    In flat-band systems, destructive interference leads to the localization of non-interacting particles and forbids their motion through the lattice. However, in the presence of interactions the overlap between neighbouring single-particle localized eigenstates may enable the propagation of bound pairs of particles. In this work, we show how these interaction-induced hoppings can be tuned to obtain a variety of two-body topological states. In particular, we consider two interacting bosons loaded into the orbital angular momentum l=1l=1 states of a diamond-chain lattice, wherein an effective π\pi flux may yield a completely flat single-particle energy landscape. In the weakly-interacting limit, we derive effective single-particle models for the two-boson quasiparticles which provide an intuitive picture of how the topological states arise. By means of exact diagonalization calculations, we benchmark these states and we show that they are also present for strong interactions and away from the strict flat-band limit. Furthermore, we identify a set of doubly localized two-boson flat-band states that give rise to a special instance of Aharonov-Bohm cages for arbitrary interactions

    Equinos (Equus caballus) da raça Marajoara em conservação na ilha do Marajó.

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    A equinocultura desenvolvida na ilha de Marajó é extensiva e o manejo é inadequado, principalmente para a conservação da raça pois, em virtude de cruzamentos indiscriminados com raças introduzidas, sofre processo de descaracterização. O estudo estå sendo realizado no BAGAM - Banco de Germoplasma Animal da AmazÎnia Oriental, em Salvaterra, ilha de Marajó, PA. Os principais descritores estudados foram: Altura da Cernelha (AC), Altura do Dorso (AD), Altura da Garupa (AG), Altura de Costados (ACo), Comprimento da Cabeça (CCa), Comprimento do Pescoço (CP), Comprimento Dorso-Lombo (CDL), Comprimento da Garupa (CG), Comprimento da Espådua (CE), Comprimento do Corpo (CC), Largura da Cabeça (LC), Largura do Peito (LP), Largura das Ancas (LA), Perímetro do Tórax (PT) e Perímetro da Canela (PC), além dos pesos nas idades padrÔes. Neste trabalho são apresentados resultados parciais referentes aos descritores, além de avaliar o comportamento e o desempenho da raça Marajoara em conservação

    A Study of Two-Temperature Non-Equilibrium Ising Models: Critical Behavior and Universality

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    We study a class of 2D non-equilibrium Ising models based on competing dynamics induced by contact with heat-baths at two different temperatures. We make a comparative study of the non-equilibrium versions of Metropolis, heat bath/Glauber and Swendsen-Wang dynamics and focus on their critical behavior in order to understand their universality classes. We present strong evidence that some of these dynamics have the same critical exponents and belong to the same universality class as the equilibrium 2D Ising model. We show that the bond version of the Swendsen-Wang update algorithm can be mapped into an equilibrium model at an effective temperature.Comment: 12 pages of LaTeX plus 18 pages of postscript figures in a uuencoded file (608k

    The SIMPLE Phase II Dark Matter Search

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    Phase II of SIMPLE (Superheated Instrument for Massive ParticLe Experiments) searched for astroparticle dark matter using superheated liquid C2_{2}ClF5_{5} droplet detectors. Each droplet generally requires an energy deposition with linear energy transfer (LET) ≳\gtrsim 150 keV/ÎŒ\mum for a liquid-to-gas phase transition, providing an intrinsic rejection against minimum ionizing particles of order 10−10^{-10}, and reducing the backgrounds to primarily α\alpha and neutron-induced recoil events. The droplet phase transition generates a millimetric-sized gas bubble which is recorded by acoustic means. We describe the SIMPLE detectors, their acoustic instrumentation, and the characterizations, signal analysis and data selection which yield a particle-induced, "true nucleation" event detection efficiency of better than 97% at a 95% C.L. The recoil-α\alpha event discrimination, determined using detectors first irradiated with neutrons and then doped with alpha emitters, provides a recoil identification of better than 99%; it differs from those of COUPP and PICASSO primarily as a result of their different liquids with lower critical LETs. The science measurements, comprising two shielded arrays of fifteen detectors each and a total exposure of 27.77 kgd, are detailed. Removal of the 1.94 kgd Stage 1 installation period data, which had previously been mistakenly included in the data, reduces the science exposure from 20.18 to 18.24 kgd and provides new contour minima of σp\sigma_{p} = 4.3 ×\times 10−3^{-3} pb at 35 GeV/c2^{2} in the spin-dependent sector of WIMP-proton interactions and σN\sigma_{N} = 3.6 ×\times 10−6^{-6} pb at 35 GeV/c2^{2} in the spin-independent sector. These results are examined with respect to the fluorine spin and halo parameters used in the previous data analysis.Comment: 20 pages, 19 figures; accepted Physical Review
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