768 research outputs found

    Four Dimensional Orbit Spaces of Compact Coregular Linear Groups

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    All four dimensional orbit spaces of compact coregular linear groups have been determined. The results are obtained through the integration of a universal differential equation, that only requires as input the number of elements of an integrity basis of the ideal of polynomial invariants of the linear group. Our results are relevant and lead to universality properties in the physics of spontaneous symmetry breaking at the classical level.Comment: 23 pages, plain LaTeX, a review that has not distributed regularl

    Cross-talk between inducible nitric oxide synthase and cyclooxygenase in Helicobacter-pylori-induced gastritis.

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    Objectives: The present study examined the cross-talk between prostanoids and nitric oxide (NO) in human gastric biopsies during Helicobacter pylori infection. Subjects and Methods: A pool of 1 or 2 biopsies per patient (11 H. pylori positive and 9 H. pylori negative) were incubated in the medium with/without drugs, 1400W and NS-398, inhibitors of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2), respectively. Levels of NO and prostaglandin E2 (PGE2), predominant products of activity of NOS and COX enzymes, were measured in the medium whereas the expressions of iNOS and COX protein, examined by Western blotting, were measured in the biopsies. Results: The 11 patients with H. pylori infection showed a marked expression of COX-2 and iNOS proteins and high levels of PGE2 and NO, as a consequence of iNOS and COX-2 activation, while proteins were absent and the level of nitrite and PGE2 was low in the 9 noninfected patients. The COX-2 inhibitor decreased both NO and PGE2. The iNOS-specific inhibitor decreased NO but did not have any effect on the increase in gastric mucosal PGE2. Both inhibitors had no effect on the protein level of these two enzymes. Conclusions: The data showed that COX-2 inhibitor might modulate the iNOS pathway, suggesting that COX-2 activity and/or its products may be related to the functional activation of iNOS but not to the expression of iNOS protein

    The meat market in Brazil: an econometric approach.

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    We describe the relative participation of the meat market (beef, pork and chicken) in Brazil in the total agribusiness and in total country?s exports. An analysis of the world meat market is carried out from the point of view of the values of consumption, production, exports and imports. A multi-criteria DEA (Data Envelopment Analysis) approach is then used to generate world market classifications. Particularly, the Brazilian insertion in the world market is viewed from these perspectives. A partial equilibrium model for the meat market is fit to Brazilian data by three stages least squares. The model is consistent with the data and is used for simulation purposes. In this context we investigate the joint and the separate effects of changes in corn price and in the exchange rate on the market endogenous variables, ceteris paribus

    Sonho, desafio e tecnologia: 35 anos de contribuições da Embrapa Suínos e Aves.

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    bitstream/item/105259/1/publicacao-1z33f2s.pdfProjeto: 11.11.11.111

    Renal function and volume of infants born with a very low birth-weight: a preliminary cross-sectional study.

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    AIM: The aim of our study was to compare the function and volumes of kidneys of very low birth-weight (VLBW) and of extremely low birth-weight (ELBW) infants at pre-school ages.PATIENTS AND METHODS: We did a revision of the neonatal records of infants born in our hospital that weighed < or =1500 g at birth. The children were divided into two groups according to their weight at birth: ELBW (<1000 g) and VLBW (1000-1500 g). At the age of 5.7 +/- 1.4 years, the children underwent clinical, laboratory and ultrasound renal assessments.RESULTS: Sixty-nine children fulfilled the requirements for the study. The rate of neonatal treatment with aminoglycosides was higher in ELBW preterms. Renal function parameters, i.e. estimated glomerular filtration rate and albuminuria, did not differ between the two groups of children. Urinary alpha1-microglobulin excretion was significantly higher and kidneys were significantly smaller in the ELBW group than in the VLBW group.CONCLUSION: No impairment or differences in renal parameters were found in pre-school children born ELBW compared with those born with VLBW, except for differences in kidney volume, renal cortical thickness and urinary alpha1-microglobulin excretion. Thus, patients born with ELBW would require a longer follow-up period

    Geometric invariant theory approach to the determination of ground states of D-wave condensates in isotropic space

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    A complete and rigorous determination of the possible ground states for D-wave pairing Bose condensates is presented, using a geometrical invariant theory approach to the problem. The order parameter is argued to be a vector, transforming according to a ten dimensional real representation of the group G=G={\bf O}3_3\otimes{\bf U}1×_1\times . We determine the equalities and inequalities defining the orbit space of this linear group and its symmetry strata, which are in a one-to-one correspondence with the possible distinct phases of the system. We find 15 allowed phases (besides the unbroken one), with different symmetries, that we thoroughly determine. The group-subgroup relations between bordering phases are pointed out. The perturbative sixth degree corrections to the minimum of a fourth degree polynomial GG-invariant free energy, calculated by Mermin, are also determined.Comment: 27 revtex pages, 2 figures, use of texdraw; minor changes in the bibliography and in Table II

    Social factors, diet and breast cancer in a northern Italian population.

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    The relation of breast cancer to social and dietary variables was evaluated in a case-control study of 368 women with breast cancer admitted to the General Hospital of Pordenone (a town in the eastern side of Northern Italy) and 373 age-matched controls. Occupation was related to the risk of breast cancer, housewives and non-manual workers (teachers and other professionals, clerical workers, etc.) showing relative risks of 1.7 and 2.4 respectively when compared to women occupied in agriculture. The role of education was apparently less important, and not statistically significant. The risk was higher in women who were obese, the trend of increasing risk with increasing body mass index being confined to post-menopausal women. When indicators of dietary fat intake were analysed, a significantly increased risk was found with more frequent consumption of milk and dairy products but the risk estimates were only slightly above unity with reference to meat consumption. Women who drank alcoholic beverages showed a relative risk of 2.5 compared to women who had never drunk, when allowance was made for all identified potential confounding factors. The association between alcohol and breast cancer was not explained by the other dietary variables considered, and the risk estimates were higher for women who drank more wine, or more than one type of alcoholic beverage. Thus, the findings of the present study give evidence in favour of the hypothesis that alcohol consumption is related to the risk of breast cancer
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