The Teleparallel Lagrangian and Hamilton-Jacobi Formalism

We analyze the Teleparallel Equivalent of General Relativity (TEGR) from the point of view of Hamilton-Jacobi approach for singular systemsComment: 11 pages, no figures, to appear in GR

Quantificação dos constituintes majoritários de extratos de timbó (Derris ssp e Lonchocarpus ssp).

Projeto 03.10.01.026.00.0

Magnetic Properties of Weakly Doped Antiferromagnets

We study the spin excitations and the transverse susceptibility of a two-dimensional antiferromagnet doped with a small concentration of holes in the t-J model. The motion of holes generates a renormalization of the magnetic properties. The Green's functions are calculated in the self-consistent Born approximation. It is shown that the long-wavelength spin waves are significantly softened and the shorter-wavelength spin waves become strongly damped as the doping increases. The spin wave velocity is reduced by the coherent motion of holes, and not increased as has been claimed elsewhere. The transverse susceptibility is found to increase considerably with doping, also as a result of coherent hole motion. Our results are in agreement with experimental data for the doped copper oxide superconductors.Comment: 20 page

In situ degradability of elephant grass ensiled with acerola by-product.

This study evaluated the inclusion of increasing contents (0; 35; 70; 105 and 140 g kg-1) of dried acerola fruit (Malpighia glabra, Linn.) by-product (DABP) in the ensilage of elephant grass (Pennisetum purpureum, Schum.) considering the in situ degradability of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and hemicellulose. Plastic drums with 210 L capacity were used as experimental silos. After 45 days of ensiling, silos were opened and silage samples were collected for the degradability trial and laboratory analysis. For the in situ degradability trial, was used one rumen-fistulated adult male cattle. The five by-product inclusion contents were tested in three replicates, with five incubation times, in a randomized complete split-plot design in which the contents of DABP were the treatments (plots), the different silos were the replicates and the incubation times were the sub-plots. Longer incubation times significantly increased (P < 0.05) the disappearance rates of DM, CP, NDF, ADF and hemicellulose. The effective degradability of the DM, NDF and hemicellulose was higher in the silages with 35 g kg-1 of DABP in the rumen passage rates of 0.02; 0.05 and 0.08 h-1. Dried acerola fruit by-product can be added to elephant grass ensiling up to 35 g kg-1 without reducing the effective degradability of nutrients

Morfometria de sementes de fava de rosca (Enterolobium schomburgkii Benth. Fabaceae) oriundas de diferentes procedências.

A fava-de-rosca é uma espécie heliófila que pode chegar até 30 m de altura, fixadora de nitrogênio, exclusiva de matas pluviais podendo ser utilizada para a recuperação de áreas degradadas. O objetivo deste trabalho foi avaliar as características morfométricas das sementes de fava-de-rosca provenientes de duas procedências do Estado do Pará. As sementes foram coletadas nos municípios de Belterra e Tucuruí (PA). Foram separadas 100 sementes de cada procedência e, realizada a biometria utilizando o paquímetro digital, mensurando comprimento, largura e espessura (mm), obteve-se também a massa expressa em miligrama de cada semente. Além das mensurações citadas foram avaliados: o teor de umidade e o número de sementes por quilogramas para a caracterização dos lotes. Análise das características biométricas foi realizada através de técnicas de estatística descritiva e apresentada em forma de boxplot construído através do programa estatístico R. O lote de sementes coletados no município de Belterra apresentou 19.048 sementes por quilograma, com 7, 6% de teor de umidade, enquanto que o lote proveniente do município de Tucuruí apresentou 14.262 sementes por quilograma, com 11, 9 % de teor de umidade. As sementes não apresentaram diferenças no aspecto biométrico com relação à procedência

Spin 1 fields in Riemann-Cartan space-times "via" Duffin-Kemmer-Petiau theory

We consider massive spin 1 fields, in Riemann-Cartan space-times, described by Duffin-Kemmer-Petiau theory. We show that this approach induces a coupling between the spin 1 field and the space-time torsion which breaks the usual equivalence with the Proca theory, but that such equivalence is preserved in the context of the Teleparallel Equivalent of General Relativity.Comment: 8 pages, no figures, revtex. Dedicated to Professor Gerhard Wilhelm Bund on the occasion of his 70th birthday. To appear in Gen. Rel. Grav. Equations numbering corrected. References update

Modifications of the BTZ black hole by a dilaton/scalar

We investigate some modifications of the static BTZ black hole solution due to a chosen asymptotically constant dilaton/scalar. New classes of static black hole solutions are obtained. One of the solutions contains the Martinez-Zanelli conformal black hole solution as a special case. Using quasilocal formalism, we calculate their mass for a finite spatial region that contains the black hole. Their temperatures are also computed. Finally, using some of the curvature singularities as examples, we investigate whether a quantum particle behaves singularly or not.Comment: 18 pages, Latex, in press in Phys. Rev.

Tratamento pré-germinativo em sementes de Albizia Pedicellaris (DC.) L. Rico.

Resumo apresentado no XIX Congresso Brasileiro de Sementes, Foz do Iguaçu, 2015