Cultivo de Arcobacter spp a partir de Diferentes Graus de Lesões de Úlcera Gástrica em Suínos

Foram examinados 20.792 estômagos de suínos abatidos em frigorífico no Rio Grande do Sul. Lesões na região esofágicaforam classificadas, desde as mais leves, de grau 1 até as mais graves, úlceras gástricas de grau 4, obtendo-se 18.657 (89,7%) estômagos com algum grau de lesão, sendo 12.148 (58,4%) de grau 1, 5.145 (24,7%) de grau 2, 1.004 (4,8%) degrau 3 e 368 (1,8%) de grau 4, comprovando a freqüência com que ocorrem úlceras gástricas em suínos. Foram realizadosexames bacteriológicos para cultivo de Arcobacter spp em amostras aleatórias de 148 estômagos, sendo 31 de cada grau delesão e 24 amostras de estômagos sem lesão. Obteve-se isolamento de 124 amostras de Arcobacter spp, classificadas porPCR como Arcobacter cryaerophilus , 98 (79,03%) e Arcobacter butzleri, 26 (20, 97%). Estes foram os primeiroscultivos de Arcobacter spp de estômagos de suínos no Brasil

Hole concentration and phonon renormalization in Ca-doped YBa_2Cu_3O_y (6.76 < y < 7.00)

In order to access the overdoped regime of the YBa_2Cu_3O_y phase diagram, 2% Ca is substituted for Y in YBa_2Cu_3O_y (y = 7.00,6.93,6.88,6.76). Raman scattering studies have been carried out on these four single crystals. Measurements of the superconductivity-induced renormalization in frequency (Delta \omega) and linewidth (\Delta 2\gamma) of the 340 cm^{-1} B_{1g} phonon demonstrate that the magnitude of the renormalization is directly related to the hole concentration (p), and not simply the oxygen content. The changes in \Delta \omega with p imply that the superconducting gap (\Delta_{max}) decreases monotonically with increasing hole concentration in the overdoped regime, and \Delta \omega falls to zero in the underdoped regime. The linewidth renormalization \Delta 2\gamma is negative in the underdoped regime, crossing over at optimal doping to a positive value in the overdoped state.Comment: 18 pages; 5 figures; submitted to Phys. Rev. B Oct. 24, 2002 (BX8292

Observational Constraints on the Angular and Spectral Distributions of Photons in Gamma-Ray Burst Sources

The typical spectra of gamma-ray bursts (GRBs) are discussed in the context of the compactness problem for GRB sources and how it is resolved in the popular fireball model. In particular, observational (model-independent) constraints on the collimation of the gamma-rays and the dependence of the collimation angle on the photon energy are considered. The fact that the threshold for the creation of $e^{-}e^{+}$ pairs depends on the angle between the momenta of the annihilating photons in the GRB source provides an alternative solution to the compactness problem. A new approach to explaining GRBs, taking into account the angular dependence for pair creation, is proposed, and the main features of a scenario describing a GRB source with a total (photon) energy smaller or of the order of $10^{49}$ erg are laid out. Thus, we are dealing with an alternative to an ultra-relativistic fireball, if it turns out (as follows from observations) that all "long" GRBs are associated with normal (not peculiar) core-collapse supernovae. The effects of radiation pressure and the formation of jets as a consequence of even a small amount of anisotropy in the total radiation field in a (compact) GRB source are examined in this alternative model. Possible energy release mechanisms acting in regions smaller or of the order of $10^{8}$ cm in size (a compact model for a GRB) are discussed. New observational evidence for such compact energy release in the burst source is considered.Comment: 15 pages, no figures, no table

Gender differences in the use of cardiovascular interventions in HIV-positive persons; the D:A:D Study

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