Caracterização do sistema de produção de leite predominante no sudeste paraense.

Perfil da produção; O produtor; A propriedade; Terras; Benfeitorias, máquinas e equipamentos; Sistema de produção; Composição do rebanho; Alimentação do rebanho; Manejo do rebanho; Produção e produtividade; Coeficientes zootécnicos; Recursos humanos; Receita bruta; Comercialização; Aquisição de insumos; Economia da produção.bitstream/item/63562/1/Oriental-Doc142.PD

Different faces of the phantom

The SNe type Ia data admit that the Universe today may be dominated by some exotic matter with negative pressure violating all energy conditions. Such exotic matter is called {\it phantom matter} due to the anomalies connected with violation of the energy conditions. If a phantom matter dominates the matter content of the universe, it can develop a singularity in a finite future proper time. Here we show that, under certain conditions, the evolution of perturbations of this matter may lead to avoidance of this future singularity (the Big Rip). At the same time, we show that local concentrations of a phantom field may form, among other regular configurations, black holes with asymptotically flat static regions, separated by an event horizon from an expanding, singularity-free, asymptotically de Sitter universe.Comment: 6 pages, presented at IRGAC 2006, Barcelona, 11-15 July 200

Unha-de-gato, usos medicinais, ocorrência e conservação a campo no Amapá, Brasil.

O presente trabalho objetiva a coleta e formação a campo do banco das espécies medicinais Uncaria guianensis e U. tomentosa, assim como realizar o levantamento dos usos medicinais e da ocorrência das mesmas no Amapá. Sua distribuição é restrita ao ecossistema de floresta tropical úmida, tanto várzea como de terra firme, em solos distróficos do Grande Grupo do Latossolo Amarelo e/ou Gley Pouco Húmico e, clima Tropical do tipo Afi e Ami. Apresenta vasta gama de usos, no entanto, até o momento, sua exploração é extrativista e sem o uso de nenhum manejo que garanta sustentabilidade na sua exploração

Experimental and theoretical evidences for the ice regime in planar artificial spin ices

In this work, we explore a kind of geometrical effect in the thermodynamics of artificial spin ices (ASI). In general, such artificial materials are athermal. Here, We demonstrate that geometrically driven dynamics in ASI can open up the panorama of exploring distinct ground states and thermally magnetic monopole excitations. It is shown that a particular ASI lattice will provide a richer thermodynamics with nanomagnet spins experiencing less restriction to flip precisely in a kind of rhombic lattice. This can be observed by analysis of only three types of rectangular artificial spin ices (RASI). Denoting the horizontal and vertical lattice spacings by a and b, respectively, then, a RASI material can be described by its aspect ratio $\gamma$=a/b. The rhombic lattice emerges when $\gamma$=$\sqrt{3}$. So, by comparing the impact of thermal effects on the spin flips in these three appropriate different RASI arrays, it is possible to find a system very close to the ice regime

Efeito da cobertura verde do solo sobre as plantas daninhas na época seca em lavouras de café em produção na região do Cerrado.

O objetivo deste trabalho foi avaliar o potencial de controle de espécies leguminosas perenes sobre as plantas daninhas em lavouras de café em produção, incorporando esta prática de condução no manejo integrado da cultura e visualizando uma cafeicultura mais sustentável com benefícios agronômicos, econômicos e ambientais

Evolution of antioxidant capacity in seeds and skins during grape maturation and their association with proanthocyanidin and anthocyanin content

In order to investigate the antioxidant activity in seeds and skins during grape maturation and their relation with anthocyanin and proanthocyanidin content, two Portuguese red grape varieties, 'Touriga Nacional' and 'Tinta Roriz' were studied. For antioxidant activity analysis, one analytical method was used (ABTS method). Different proanthocyanidins fractions according to their degree of polymerization were analyzed, while 13 different individual anthocyanins were evaluate by HPLC as well. During the maturation period the antioxidant activity content quantified from the different grape berry fractions was characterized by a general decrease with a slight oscillation in the early stages of maturation, followed by a stabilization and slight increase of the values in the last weeks of ripening. Similar evolution was observed for the different proanthocyanidins fractions quantified. For the individual anthocyanins, in general the evolution was characterized by a slowly increase in the first 3 weeks of ripening process, followed by a marked increase and finally a slight decrease or stabilization in the last weeks of ripening. Finally, high linear positive correlations between proanthocyanidin fractions and the antioxidant activity evolution during the grape maturation were obtained while for the individual anthocyanins a high negative correlation values was quantified

The anisotropic XY model on the inhomogeneous periodic chain

The static and dynamic properties of the anisotropic XY-model $(s=1/2)$ on the inhomogeneous periodic chain, composed of $N$ cells with $n$ different exchange interactions and magnetic moments, in a transverse field $h,$ are determined exactly at arbitrary temperatures. The properties are obtained by introducing the Jordan-Wigner fermionization and by reducing the problem to a diagonalization of a finite matrix of $nth$ order. The quantum transitions are determined exactly by analyzing, as a function of the field, the induced magnetization 1/n\sum_{m=1}^{n}\mu_{m}\left ($j$ denotes the cell, $m$ the site within the cell, $\mu_{m}$ the magnetic moment at site $m$ within the cell) and the spontaneous magnetization $1/n\sum_{m=1}^{n}\left< S_{j,m}^{x},\right>$ which is obtained from the correlations $\left< S_{j,m}^{x}S_{j+r,m}^{x}\right>$ for large spin separations. These results, which are obtained for infinite chains, correspond to an extension of the ones obtained by Tong and Zhong(\textit{Physica B} \textbf{304,}91 (2001)). The dynamic correlations, $\left< S_{j,m}^{z}(t)S_{j^{\prime},m^{\prime}}^{z}(0)\right>$, and the dynamic susceptibility, $\chi_{q}^{zz}(\omega),$ are also obtained at arbitrary temperatures. Explicit results are presented in the limit T=0, where the critical behaviour occurs, for the static susceptibility $\chi_{q}^{zz}(0)$ as a function of the transverse field $h$, and for the frequency dependency of dynamic susceptibility $\chi_{q}^{zz}(\omega)$.Comment: 33 pages, 13 figures, 01 table. Revised version (minor corrections) accepted for publiction in Phys. Rev.