RESUMO Objetivou-se avaliar os efeitos de antioxidantes suplementados às dietas de galos de matrizes pesadas em idade avançada sobre as características reprodutivas. Foram utilizados galos da linhagem Cobb com 47 semanas de idade. Estes foram distribuídos em quatros tratamentos, de acordo com a adição de antioxidante à dieta, sendo: A = grupo controle (sem suplementação antioxidante); B = suplementação de 9ppm de citranaxantina; C = suplementação de 6ppm de cantaxantina e D = 150ppm de vitamina E. Foram avaliadas as características seminais, tais como volume, vigor, motilidade e concentração, a composição de ácidos graxos do sêmen (saturados, insaturados, monoinsaturados, poli-insaturados, ômega 3, ômega 6 e ômega 9) e a correlação entre o peso dos testículos e o peso dos galos. Não foram observados efeitos das substâncias antioxidantes testadas sobre os parâmetros reprodutivos avaliados. Os antioxidantes avaliados não influenciam as respostas reprodutivas de machos reprodutores de matrizes pesadas em idade avançada.

ABSTRACT This study aimed to evaluate the effect of antioxidant supplementation in diets of aging broiler breeder roosters on reproductive characteristics. Cobb roosters were divided into four groups, according to antioxidant addition, where: A = control group (without antioxidant supplementation); B = 9ppm of citranaxanthin; C = 6ppm of canthaxanthin, and D = 150ppm of vitamin E. Seminal characteristics (volume, force, motility and concentration), semen fatty acid composition (saturated, unsaturated, monounsaturated, polyunsaturated, ω3, ω6 and ω9), and the correlation between testis weight with rooster weight were evaluated. No effects of the antioxidants tested were observed. The antioxidants do not influence the reproductive responses of aging male broiler breeder.

O objetivo deste artigo é apresentar e discutir alguns aspectos da patogênese, do diagnóstico clínico, hormonal e radiológico e do tratamento da síndrome de Nelson, com base no relato de um paciente típico portador da doença, no qual várias abordagens terapêuticas mostraram-se ineficazes.

The aim of this article is to present and discuss several aspects of the pathogenesis, the clinical, hormonal, and imaging diagnosis, and the treatment of Nelson's syndrome, based on a typical patient's report, in whom several therapeutic approaches were shown to be ineffective.

We use Monte Carlo and Molecular Dynamics simulation to study a magnetic tip-sample interaction. Our interest is to understand the mechanism of heat dissipation when the forces involved in the system are magnetic in essence. We consider a magnetic crystalline substrate composed of several layers interacting magnetically with a tip. The set is put thermally in equilibrium at temperature T by using a numerical Monte Carlo technique. By using that configuration we study its dynamical evolution by integrating numerically the equations of motion. Our results suggests that the heat dissipation is closed related to the appearing of vortices in the sample.

The thermal behavior of the (010), (110) and (111) copper surfaces is studied by molecular dynamics simulation. We have used a many-body potential based on the tight-binding model in order to describe the Cu-Cu interaction. The calculations we have performed correspond to simulations in the temperature range between 600 and 1800 K. The observed order in the stability follows the same order as in the packing density, i. e., (110), (010) and (111). The (110) disorder results from anharmonic effects and by vacancy-adatom formation. On the other end, the (111) surface is very stable, and remains so up to temperatures of the order of the bulk melting point. The melting proceeds by a layer-by-layer mechanism.

Using Monte Carlo simulations we have investigated the critical behavior of the classical fully frustrated XY model in two dimensions in a square lattice. There are two phase transitions in the model, one of the Berezinskii-Kosterlitz-Thouless type and a Z2 transition at higher temperature. We show that the vortex anti-vortex density has a clear signature of the Z2 phase transition at exactly the percolation threshold.

In this work we use molecular dynamics simulation to study the clustering of dust particles deposited on a liquid surface. Our results are compatible with the picture that one particle attracts another due to the deformation of the liquid medium which creates an attractive potential around the deposited particle. The similarity to other physical phenomena is discussed.

We perform molecular dynamics simulations of directional growth of a binary alloy. We fix the temperature gradient, pulling speed, impurity concentration and only vary the impurity segregation coefficient. By changing the range of the Lennard Jones potential of impurity atoms as compared to the range of the potential of solvent atoms, the elastic energy cost causes a decreases of solubility of the impurity atoms into the matrix (solvent) solid phase and consequently a decrease in the impurity segregation coefficient. Within certain range of segregation coefficients, the growing interface is planar; below it, the interface becomes unstable and a cellular structure emerges.