Massive scalar field near a cosmic string

The $\zeta$ function of a massive scalar field near a cosmic string is computed and then employed to find the vacuum fluctuation of the field. The vacuum expectation value of the energy-momentum tensor is also computed using a point-splitting approach. The obtained results could be useful also for the case of self-interacting scalar fields and for the finite-temperature Rindler space theory.Comment: 15 pages, standard LaTeX, no figures. Reference [14] correcte

A nearly cylindrically symmetric source in the Brans-Dicke gravity as the generator of the rotational curves of the galaxies

Observation shows that the velocities of stars grow by approximately 2 to 3 orders of magnitude when the distances from the centers of the galaxies are in the range of $0.5$ kpc to $82.3$ kpc, before they begin to tend to a constant value. Up to know, the reason for this behavior is still a matter for debate. In this work, we propose a model which adequately describes this unusual behavior using a (nearly) cylindrical symmetrical solution in the framework of a scalar-tensor-like (the Brans-Dicke model) theory of gravity.Comment: 24 pages, 4 figures, accepted for publication in Eur. Phys. J.

Mapa da cobertura vegetal do Estado de Goiás.

O artigo divulga os resultados do levantamento cartográfico realizado na cobertura vegetal do Estado de Goiás

Cartografia e monitoramento orbital da sazonalidade das Unidades de Vegetação da Região de Vitória da Conquista (BA).

Esse trabalho procurou identificar, cartografar, quantificar e analisar as unidades de vegetação, assim como seus respectivos comportamentos sazonais, dispostas em uma área de transição entre a floresta semidecidual e a caatinga, entre as coordenadas geográficas 14º00´/15º00´S e 40º30´/42º00´W, no sudoeste do Estado da Bahia. Foram utilizadas e manipuladas Sistemas de Informações Geográficas, interpretações analógicas de imagens do sensor TM-LANDSAT e composições quinzenais de máximo valor do IVDN-AVHRR-NOAA, resultando na cartografia, quantificação e na análise da sazonalidade de quatro unidades de vegetação, mata de cipó, caatinga densa, caatinga aberta e caatinga carrasco, além de correlações lineares entre os valores IVDN e pluviométricos

Population Dynamic, Anthelmintic Treatments and the Influence of Helminth Infections on Weight Gain in Water Buffalo Calves (Bubalus Bubalis)

The dynamics of gastrointestinal helminthiasis was studied in buffalo calves naturally exposed to helminth infection at two farms in Minas Gerais, Brazil. The effect of helminthiasis was evaluated with respect to weight gain of naturally infected untreated calves versus those which received anthelmintic treatment either with fenbendazole or ivermectin. The treated animals had significantly (p<0.05) higher weight gain. Strongyloides papillosus was diagnosed from 30 to 60 days after birth, and Toxocara vitulorum from 60 to 90 days. During spring, there was a rise in the eggs per gram (EPG) count of Trichostrongylidae. Severe infection of Paracooperia nodulosa was detected in few 9-month-old buffalo calves.The results of this study indicate efficacy of fenbendazole and ivermectin in different age group calves for better health and reduced probability of helminth resistance. This study also indicates the necessity for good nutritional management of buffalo calves to improve the efficacy of parasite control