38 resultados para indirizzo :: 069 :: Didattico


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Hypoxia causes a regulated decrease in body temperature (Tb). There is circumstantial evidence that the neurotransmitter serotonin (5-HT) in the anteroventral preoptic region (AVPO) mediates this response. However, which 5-HT receptor(s) is (are) involved in this response has not been assessed. Thus, we investigated the participation of the 5-HT receptors (5-HT(1), 5-HT(2), and 5-HT(7)) in the AVPO in hypoxic hypothermia. To this end, Tb of conscious Wistar rats was monitored by biotelemetry before and after intra-AVPO microinjection of methysergide (a 5-HT(1) and 5-HT(2) receptor antagonist, 0.2 and 2 mu g/100 nL), WAY-100635 (a 5-HT(1A) receptor antagonist, 0.3 and 3 mu g/100 nL), and SB-269970 (a 5-HT(7) receptor antagonist, 0.4 and 4 mu/100 nL), followed by 60 min of hypoxia exposure (7% O(2)). During the experiments, the mean chamber temperature was 24.6 +/- 0.7 degrees C (mean +/- SE) and the mean room temperature was 23.5 +/- 0.8 degrees C (mean +/- SE). Intra-AVPO microinjection of vehicle or 5-HT antagonists did not change Tb during normoxic conditions. Exposure of rats to 7% of inspired oxygen evoked typical hypoxia-induced hypothermia after vehicle microinjection, which was not affected by both doses of methysergide. However, WAY-100635 and SB-269970 treatment attenuated the drop in Tb in response to hypoxia. The effect was more pronounced with the 5-HT7 antagonist since both doses (0.4 and 4 mu g/0.1 mu L) were capable of attenuating the hypothermic response. As to the 5-HT(1A) antagonist, the attenuation of hypoxia-induced hypothermia was only observed at the higher dose. Therefore, the present results are consistent with the notion that 5-HT acts on both 5-HT(1A) and 5-HT7 receptors in the AVPO to induce hypothermia, during hypoxia. (c) 2005 Elsevier B.V All rights reserved.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Foram estimados os coeficientes de herdabilidade e a mudança genética para peso à desmama (PD), peso ao sobreano (PS), ganho de peso do nascimento à desmama (GND), ganho de peso da desmama ao sobreano (GDS), perímetro escrotal (PE) e idade ao primeiro parto (IPP) em animais da raça Nelore. Foram utilizados dados de 128.148 animais nascidos entre 1984 e 2006. Os componentes de variância foram estimados pelo método da máxima verossimilhança restrita, e os valores genéticos foram preditos por modelos mistos aplicando-se modelo animal bicaracterística, incluindo peso à desmama em todas as análises. As tendências genéticas foram estimadas pela regressão dos valores genéticos sobre o ano de nascimento dos animais. Os coeficientes de herdabilidade do efeito direto estimados foram de 0,23 (0,07) (PD); 0,24 (0,02) (PS); 0,21 (0,01) (GND); 0,23 (0,01) (GDS); 0,46 (0,02) (PE) e 0,15 (0,01) (IPP). As tendências genéticas diretas estimadas foram de 0,171 (0,01); 0,219 (0,02); 0,186 (0,03) e 0,224 (0,02) kg/ano para PD, PS, GND e GDS, respectivamente, o que representa incrementos de 0,10; 0,08; 0,13 e 0,22% nas médias das mesmas características ao ano, respectivamente. Para o PE e a IPP no período de 1984 a 1995, as tendências genéticas foram nulas, com valores de 0,011 (0,03) cm/ano e -0,003 (0,06) dias/ano, respectivamente. No segundo período considerado (1996 a 2006), as tendências genéticas para PE e IPP foram de 0,069 (0,01) cm/ano e -3,024 (0,04) dias/ano, respectivamente, indicando melhorias consideráveis em tais características. Esses valores sugerem que características produtivas e reprodutivas, quando utilizadas como critério de seleção, proporcionam progresso genético no rebanho, sendo indicadas para seleção de animais da raça Nelore.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The fly of the syrphid Microdon tigrinus is a specific social parasite of leaf-cutting ant, Acromyrmex coronatus. Six colonies of Acromyrmex coronatus were collected in plastic containers, which there was a layer of 1 cm of plaster, with the purpose of maintaining the humidity of fungus culture. Larvae of social parasite were separate for the establishment of instars number, through morphometric study. The data were measured of 165 larvae, using spiracle (length (Ls), width (Ws) and distance between spiracle (Ds)). After that, the morphometric data obtained for the larvae were submitted to cluster analysis by Wong's hybrid method, which produces the adequate number of groups through pseudo F-statistics and pseudo t-squared statistics. The three morphometric variables studied permitted grouping of larvae into the following three distinct groups: cluster 1 [long dash] consisting of 55 larvae (Ls=0.177[plus or minus]0.026, Ws=0.163[plus or minus]0.030, Ds=0.052[plus or minus]0.008 mm); cluster 2 - consisting of 20 larvae (Ls=0.631[plus or minus]0.065, Ws=0.630[plus or minus]0.049, Ds=0.065[plus or minus]0.018 mm); cluster 3 - consisting of 90 larvae (Ls=1.294[plus or minus]0.062, Ws=1.308[plus or minus]0.069, Ds=0.140[plus or minus]0.018 mm). of the all couples, only 1 obtained success in the mating, and the female, after 24 hours, began the oviposition. The female layed 76 eggs in a period of 6 days, after that, her death. The larvae emerged in the seventh day (incubation period [plus or minus] 7 days). From 76 eggs, 54 were viable, with a viability of 71.05%. This study contributes to the knowledge of Microdon tigrinus biology of, a social parasite poorly studied in Brazil.

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A solid paraffin-based carbon paste electrode modified with 2-aminothiazole organofunctionalized silica (SiAt-SPCPE) was applied to Ni2+ determination in commercial ethanol fuel samples. The proposed method comprised four steps: (1) Ni2+ preconcentration at open circuit potential directly in the ethanol fuel sample, (2) transference of the electrode to an electrochemical cell containing DMG, (3) differential pulse voltammogram registering and (4) surface regeneration by polishing the electrode. The proposed method combines the high Ni2+ adsorption capacity presented by 2-aminothiazole organofunctionalized silica with the electrochemical properties of the Ni(DMG)2 complex, whose electrochemical reduction provides the analytical signal.All experimental parameters involved in the proposed method were optimized. Using a preconcentration time of 20 min, it was obtained a linear range from 7.5 x 10(-9) to 1.0 x 10(-6) mol L-1 with detection limit of 2.0 x 10(-9) mol L-1. Recovery values between 96.5 and 102.4% were obtained for commercial samples spiked with 1.0 mu mol L-1 Ni2+ and the developed electrode was totally stable in ethanolic solutions. The contents of Ni2+ found in the commercial samples using the proposed method were compared to those obtained by graphite furnace atomic absorption spectroscopy by using the F- and t-test. Neither the F- nor t-values exceeded the critical values at 95% confidence level, confirming that there are not statistical differences between the results obtained by both methods. These results indicate that the developed electrode can be successfully employed to reliable Ni2+ determination in commercial ethanol fuel samples without any sample pretreatment or dilution step. (c) 2006 Elsevier B.V. All rights reserved.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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A sociedade contemporânea vê-se desafiada a responder qualitativamente às demandas da ciência e da tecnologia, cujas ressonâncias afetam as múltiplas dimensões humanas. Uma delas, o aumento da longevidade, vem requisitando políticas e programas sociais voltados à qualidade de vida, incluindo o âmbito do lazer. Este estudo qualitativo objetivou identificar aspectos emocionais na percepção de idosos, durante vivências no lazer. Os dados foram coletados por meio de questionário misto, aplicado a uma amostra de 20 participantes, de ambos os sexos. Foram analisados descritivamente pela Técnica de Análise de Conteúdo, revelando recorrências de crescimento positivo como a relação interpessoal e o respeito mútuo, a contemplação, a sensação de harmonia com a natureza, o elemento lúdico, entre outros, também responsáveis pelo vínculo afetivo do grupo. Conclui-se que experiências significativas no âmbito do lazer, capazes de contemplar a gama de necessidades e expectativas do homem, contribuem para a ressignificação emocional do lazer nesta fase do desenvolvimento.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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By incorporating the holographic principle in a time-depending Lambda-term cosmology, new physical bounds on the arbitrary parameters of the model can be obtained. Considering then the dark energy as a purely geometric entity, for which no equation of state has to be introduced, it is shown that the resulting range of allowed values for the parameters may explain both the coincidence problem and the universe accelerated expansion, without resorting to any kind of additional structures. (C) 2006 Elsevier B.V. All rights reserved.

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We present new results of the search for WH --> lvb (b) over bar production in p (p) over bar collisions at a center-of-mass energy of root S = 1.96 TeV, based on a dataset with integrated luminosity of 0.44 fb(-1). We combine these new results with previously published searches by the do collaboration, for WH and ZH production analyzed in the E(T)b (b) over bar final state, for ZH (--> l(+)l(-)b (b) over bar) production, for WH (-->. WWW) production, and for H (--> W W) direct production. No signal-like excess is observed either in the W H analysis or in the combination of all D0 Higgs boson analyses. We set 95% C.L. (expected) upper limits on sigma(p (p) over bar --> WH) x B(H --> b (b) over bar) ranging from 1.6 (2.2) ph to 1.9 (3.3) pb for Higgs boson masses between 105 and 145 GeV, to be compared to the theoretical prediction of 0.13 pb for a Standard Model (SM) Higgs boson with mass in m(H) = 115 GeV. After combination with the other do Higgs boson searches, we obtain for in H = 115 GeV an observed (expected) limit 8.5 (12.1) times higher than the SM predicted Higgs boson production cross section. For m(H) = 160 GeV, the corresponding observed (expected) ratio is 10.2 (9.0). (C) 2008 Elsevier B.V. All rights reserved.

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Intense violet-blue photoluminescence (PL) emission at room temperature was verified in BaZrO3 (BZO) powders with structural order-disorder. Ab-initio calculations, ultraviolet-visible absorption spectroscopy and PL were performed. Theoretical results showed that the local disorder in the network-formed Zr clusters present an important role in the formation of hole-electron pair. The experimental data and theoretical results are in agreement, indicating that the PL emission in BZO powders can be related to the structural order-disorder degree in the lattice. (C) 2008 Elsevier B.V. All rights reserved.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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A idade e o crescimento do pintado Pseudoplatystoma corruscans foram estudados durante o período de maio de 1994 a maio de 1995. O comprimento-padrão variou de 52 a 145 cm e o peso total, de 1,3 a 41 kg. As relações biométricas entre comprimento-padrão (Ls) e comprimento total (Ltotal) e entre peso total (Wt) e comprimento-padrão (Ls) foram obtidas, sendo, respectivamente: Ltotal = 3,296 + 1,069 * Ls e Wt = 0,00624 * Ls3,134. O fator de condição, calculado mensalmente, sugere que a desova ocorreu entre os meses de fevereiro e março. A idade foi estimada pela contagem de anéis de crescimento presentes nos raios modificados (esporão) das nadadeiras peitorais, detectando 10 classes etárias. A distância média do último anel até a borda do esporão sugere que o período de menor crescimento ocorreu entre julho e setembro (seca). A equação de von Bertalaffy que descreve o crescimento do pintado é: Lt = 183 * [1 - exp - 0,085 * (t + 3,274)]. A mortalidade total obtida foi Z = 0,24 ano-1 e a mortalidade natural M = 0,20 ano-1. Com o presente nível de explotação, F = Z - M = 0,04 ano-1, conclui-se que o estoque do pintado ainda não estava sobrexplotado na bacia do rio Cuiabá, Pantanal Matogrossense, na época em que foi realizado o estudo.

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The thermal conductivity of several commercial ZnO-based varistor systems was determined based on the laser-pulse method, a technique that proved extremely useful and easy to apply. Using this technique, the thermal conductivity was found to be dependent on the microstructural features of the devices, involving the mean grain size and phase composition. Among the phases existing in commercial ZnO-based varistors, ZniSb2O12 and Bi2O3 were found to contribute strongly to the thermal conductivity of the devices. (C) 2003 Elsevier B.V. All rights reserved.