954 resultados para Linear forms in logarithms
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Many new viscoelastic materials have been developed recently to help improve noise and vibration levels in mechanical structures for applications in automobile and aeronautical industry. The viscoelastic layer treatment applied to solid metal structures modifies two main properties which are related to the mass distribution and the damping mechanism. The other property controlling the dynamics of a mechanical system is the stiffness that does not change much with the viscoelastic material. The model of such system is usually complex, because the viscoelastic material can exhibit nonlinear behavior, in contrast with the many available tools for linear dynamics. In this work, the dynamic behavior of sandwich beam is modeled by finite element method using different element types which are then compared with experimental results developed in the laboratory for various beams with different viscoelastic layer materials. The finite element model is them updated to help understand the effects in the damping for various natural frequencies and the trade-off between attenuation and the mass add to the structure.
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Some authors consider minerals from organic sources more bioavailable for pig nutrition in comparison with inorganic sources. To evaluate the relative iron bioavailability from the organic source iron carbo-amino-phospho-chelate (ICAPC) to weanling piglets, it was conducted an experiment with 126 commercial piglets, using iron sulfate monohydrate (S) as standard. The experiment had a randomized block design with seven treatments (diet without adding specific source of iron, diet with 50, 100 and 150 ppm iron from S and diet with 50, 100 and 150 ppm iron from ICAPC), six replications and three animals per experimental unit. Performance parameters (average daily gain - ADG, feed: gain ratio - F:G) and blood variables (hemoglobin - Hb, hematocrit - Ht, transferrin - TR, latent iron-binding capacity - LIBC, total iron-binding capacity - TIBC, serum iron - Fe and transferrin saturation index - TSI) were evaluated. At the end of the experiment a piglet from each experimental unit was slaughtered and its liver and spleen removed for assessment of iron concentration by flame atomic absorption spectrometry (FAAS). The evaluated sources of iron yielded similar results for the variables of interest, but the increase in iron intake was followed by a linear increase in ADG, Hb, Ht, Fe and TSI as well as a linear decrease in the values of F:G, TR, LIBC and TIBC. Iron bioavailabilities from both ICAPC and S sources are similar for weanling piglets.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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We use the method of Monte Carlo evolution in the coupling constant space of Ferrenberg and Swendsen to evaluate the nonuniversal exponent η* associated to a linear defect in a 2d Ising model. © 1989.
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Pós-graduação em Agronomia - FEIS
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The objective of this study was to analyze the influence of genetic group (GG) of the calf during gestation, mobilization of body reserves and period of postpartum anestrus in Nellore cows. Thirty-seven primiparous and multiparous cows were used: 24 gave birth to Nellore (NEL), and 13 gave birth to 1/2 Simmental x 1/2 Nellore (SIM) calves. According to the date of calving, cows were divided into three blocks, with intervals of 20 days between blocks. The body condition (BC) of the cows was estimated subjectively on a scale from 0 to 5 points, with intermediate grading of 0.5 points. We measured the thickness of subcutaneous fat (SF) between the 12th and 13th ribs and rump by ultrasound. Blood samples from each cow were collected weekly from the third week after birth until weaning, to analyze the level of progesterone; in the samples collected until 16 weeks postpartum, we analyzed the concentration of nonesterified fatty acids(NEFA). The gestation period of mothers of NEL calves was eight days longer, on average. The variables relating to the mobilization of body reserves (NEFA, BC and SF) were not influenced by calf GG, with the only significant effects being the number of days postpartum, witha peak in the concentration of NEFA between the sixth and eighth weeks and linear decrease in BC and NF. Mothers of NEL calves remained in anestrus for 4.6 weeks longer than the mothers of crossbred calves.
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Estudou-se a melhor relação entre lisina digestível (LIS) e energia metabolizável (EM) e efeitos no desempenho e balanço de nitrogênio em leitões na fase de creche. No desempenho foram usados 216 leitões dos 6,90 ± 1,11 kg de peso inicial aos 12 kg, aproximadamente. No metabolismo eram 48 leitões com 9,31 ± 2,09 kg. As concentrações de LIS eram: 1,302; 1,390 e 1,497% e de EM: 3.510, 3.700 e 3.830 kcal/kg, combinadas em um arranjo fatorial 3 × 4 e distribuídas em delineamento de blocos ao acaso. No desempenho dos leitões houve interação LIS em no ganho de peso e conversão alimentar. No ganho de peso a resposta para LIS foi linear crescente nas dietas com 3.510 kcal e 3.830 kcal de EM. Na conversão alimentar observou-se efeito quadrático de LIS nas dietas que continham 3.510 kcal e efeito linear de LIS nas dietas com 3.830 kcal de EM. O efeito quadrático de LIS dentro de 3.510 kcal indicou 1,44% do aminoácido digestível como nível ótimo ou a ingestão de 4,16 g LIS/Mcal de em consumida. A resposta linear positiva na conversão alimentar ao acréscimo de LIS nas dietas com 3.830 kcal em indica maior eficiência dos leitões ao acréscimo do aminoácido quando o nível de energia é alto. No ensaio de metabolismo o aumento de em sugere maior retenção de N, enquanto o acréscimo de LIS sugere menor retenção do N ou na relação Mcal de EM:% LIS. A interação observada nos dois ensaios, todavia, indica que a relação LIS:EM, depende do nível energético e da característica considerada. A variação de LIS e em na dieta indica 4 g LIS/Mcal de em consumida, o que corresponde à ingestão diária aproximada de 7,8 g de LIS.