1,411 research outputs found
O perfil da indústria de laticínios na Zona da Mata e Campo das Vertentes de Minas Gerais.
Cenário econômico mundial; Cenário econômico brasileiro; Cenário macroeconômico regional: Zona da Mata e Campo das Vertentes; Evolução do setor lácteo brasileiro.bitstream/item/132488/1/Livro-O-perfil-da-industria-de-laticinios.pd
Relação entre polimorfismos no gene da leptina, ganho de peso e concentração sérica de leptina em bovinos de corte.
O objetivo do trabalho é estabelecer a relação de polimorfismos no gene da leptina com a quantidade de leptina sérica e ganho de peso durante o confinamento, visando a utilização de dados obtidos em programas de seleção animal. Os bovinos confinados utilizados na pesquisa serão provenientes da Fazenda Tuju Puitan. Serão objetos da pesquisa 100 animais com idade média de 12 meses
Possible chiral phase transition in two-dimensional solid He
We study a spin system with two- and four-spin exchange interactions on the
triangular lattice, which is a possible model for the nuclear magnetism of
solid He layers. It is found that a novel spin structure with scalar chiral
order appears if the four-spin interaction is dominant. Ground-state properties
are studied using the spin-wave approximation. A phase transition concerning
the scalar chirality occurs at a finite temperature, even though the
dimensionality of the system is two and the interaction has isotropic spin
symmetry. Critical properties of this transition are studied with Monte Carlo
simulations in the classical limit.Comment: 4 pages, Revtex, 4 figures, to appear in Phys.Rev.Let
Magnetization plateau in a two-dimensional multiple-spin exchange model
We study a multiple-spin exchange model on a triangular lattice, which is a
possible model for low-density solid 3He films. Due to strong competitions
between ferromagnetic three-spin exchange and antiferromagnetic four-spin one,
the ground states are highly degenerate in the classical limit. At least
2^{L/2}-fold degeneracy exists on the L*L triangular lattice except for the
SO(3) symmetry. In the magnetization process, we found a plateau at
m/m_{sat}=1/2, in which the ground state is "uuud state" (a collinear state
with four sublattices). The 1/2-plateau appears due to the strong four-spin
exchange interaction. This plateau survives against both quantum and thermal
fluctuations. Under a magnetic field which realizes the "uuud" ordered state, a
phase transition occurs at a finite temperature. We predict that low-density
solid 3He thin films may show the 1/2-plateau in the magnetization process.
Experimental observation of the plateau will verify strength of the four-spin
exchange. It is also discussed that this magnetization plateau can be
understood as an insulating-conducting transition in a particle picture.Comment: 10 pages, RevTeX, 12 figures, added a reference and corrected typos,
to be published in Phys.Rev.B (01 APR 99
High-resolution abundance analysis of red giants in the metal-poor bulge globular cluster HP~1
The globular cluster HP~1 is projected at only 3.33 degrees from the Galactic
center. Together with its distance, this makes it one of the most central
globular clusters in the Milky Way. It has a blue horizontal branch (BHB) and a
metallicity of [Fe/H]~-1.0. This means that it probably is one of the oldest
objects in the Galaxy. Abundance ratios can reveal the nucleosynthesis pattern
of the first stars as well as the early chemical enrichment and early formation
of stellar populations. High-resolution spectra obtained for six stars were
analyzed to derive the abundances of the light elements C, N, O, Na, and Al,
the alpha-elements Mg, Si, Ca, and Ti, and the heavy elements Sr, Y , Zr, Ba,
La, and Eu.} High-resolution spectra of six red giants that are confirmed
members of the bulge globular cluster HP~1 were obtained with the 8m VLT
UT2-Kueyen telescope with the UVES spectrograph in FLAMES-UVES configuration.
The spectroscopic parameter derivation was based on the excitation and
ionization equilibrium of FeI and FeII. We confirm a mean metallicity of [Fe/H]
= -1.06~0.10, by adding the two stars that were previously analyzed in HP~1.
The alpha-elements O and Mg are enhanced by about +0.3<[O,Mg/Fe]<+0.5 dex, Si
is moderately enhanced with +0.15<[Si/Fe]<+0.35dex, while Ca and Ti show lower
values of -0.04<[Ca,Ti/Fe]<+0.28dex. The r-element Eu is also enhanced with
[Eu/Fe]~+0.4, which together with O and Mg is indicative of early enrichment by
type II supernovae. Na and Al are low, but it is unclear if Na-O are
anticorrelated. The heavy elements are moderately enhanced, with
-0.20<[La/Fe]<+0.43dex and 0.0<[Ba/Fe]<+0.75~dex, which is compatible with
r-process formation. The spread in Y, Zr, Ba, and La abundances, on the other
hand, appears to be compatible with the spinstar scenario or other additional
mechanisms such as the weak r-process.Comment: 15 pages, 8 figures In press in Astronomy & Astrophysics (2016
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