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
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 benchmark models assuming slowly rotating cores. For red
giant stars with slowly rotating cores, we show that the variation of the
rotational splittings of 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 (). This leds us to propose a
way to infer directly 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.
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
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
states of a diamond-chain lattice, wherein an effective 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.
A equinocultura desenvolvida na ilha de MarajĂł Ă© extensiva e o manejo Ă© inadequado, principalmente para a conservação da raça pois, em virtude de cruzamentos indiscriminados com raças introduzidas, sofre processo de descaracterização. O estudo estĂĄ sendo realizado no BAGAM - Banco de Germoplasma Animal da AmazĂŽnia Oriental, em Salvaterra, ilha de MarajĂł, 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 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. Neste trabalho sĂŁo apresentados resultados parciais referentes aos descritores, alĂ©m 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
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
Phase II of SIMPLE (Superheated Instrument for Massive ParticLe Experiments)
searched for astroparticle dark matter using superheated liquid
CClF droplet detectors. Each droplet generally requires an energy
deposition with linear energy transfer (LET) 150 keV/m for a
liquid-to-gas phase transition, providing an intrinsic rejection against
minimum ionizing particles of order 10, and reducing the backgrounds to
primarily 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- 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
= 4.3 10 pb at 35 GeV/c in the
spin-dependent sector of WIMP-proton interactions and = 3.6
10 pb at 35 GeV/c 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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