1,255 research outputs found

    O Brasil no cenário mundial de lácteos.

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    Thermo mechanic response of a ceramic material coated with gold

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    The present report has as the main objective to obtain, via the experimental process, the thermal response of a ceramic material coated with gold, when subjected to a variation of temperature. Under this context, the main information that it is important to be obtained consists in the calculation of the specific deformation, ε of the composite material (ceramic substrate coated with a gold top layer) that it is generated due to a temperature variation of about 100ºC. This information is of extreme importance because it imposes the adoption of specific techniques to be implemented in civil construction. It must be enhanced that the experimental activity also considered the study of the chemical composition and the morphology of the materials that were supplied by the manufacturer. In fact, this is essential information, since its knowledge helps to correlate and to interpret the thermo-mechanics response

    Optimization of particle bombardment parameters for the genetic transformation of Brazilian maize inbred lines.

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    ABSTRACT: The objective of this work was to develop a genetic transformation system for tropical maize genotypes via particle bombardment of immature zygotic embryos. Particle bombardment was carried out using a genetic construct with bar and uidA genes under control of CaMV35S promoter. The best conditions to transform maize tropical inbred lines L3 and L1345 were obtained when immature embryos were cultivated, prior to the bombardment, in higher osmolarity during 4 hours and bombarded at an acceleration helium gas pressure of 1,100 psi, two shots per plate, and a microcarrier flying distance of 6.6 cm. Transformation frequencies obtained using these conditions ranged from 0.9 to 2.31%. Integration of foreign genes into the genome of maize plants was confirmed by Southern blot analysis as well as bar and uidA gene expressions. The maize genetic transformation protocol developed in this work will possibly improve the efficiency to produce new transgenic tropical maize lines expressing desirable agronomic characteristics. RESUMO: O objetivo deste trabalho foi desenvolver um sistema de transformação genética para genótipos tropicais de milho pelo bombardeamento de embriões imaturos com micropartículas. O bombardeamento com partículas foi realizado utilizando-se uma construção gênica contendo os genes bar e uidA sob o controle do promotor CaMV35S. As melhores condições para transformação das linhagens de milho tropical L3 e L1345 foram obtidas após o cultivo de embriões imaturos durante 4 horas, antes do bombardeamento, em alta osmolaridade, e bombardeados com a pressão de 1.100 psi de gás hélio, dois tiros por placa e uma distância de vôo da micropartícula de 6,6 cm. As freqüências de transformação obtidas variaram entre 0,9 e 2,31%. A integração dos genes heterólogos no genoma das plantas transgênicas de milho foi confirmada por análises de Southern blot e expressão dos genes bar e uidA. O protocolo de transformação genética de milho desenvolvido neste estudo irá aumentar, provavelmente, a eficiência de produção de novas linhagens tropicais de milho expressando características agronômicas desejáveis

    Decaying Lambda cosmology, varying G and holography

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    We discuss a class of uniform and isotropic, spatially flat, decaying Lambda cosmologies, in the realm of a model where the gravitation constant G is a function of the cosmological time. Besides the usual de Sitter solution, the models at late times are characterized by a constant ratio between the matter and total energy densities. One of them presents a coasting expansion where the matter density parameter is equal to 1/3, and the age of the universe satisfies Ht = 1. From considerations in line with the holographic conjecture, it is argued that, among the non-decelerating solutions, the coasting expansion is the only acceptable from a thermodynamic viewpoint, and that the time varying cosmological term must be proportional to the square of the Hubble parameter, a result earlier obtained using different arguments.Comment: Minor changes. A short version will appear in the Int. J. Mod. Phys. A (Proceedings of the Sixth Alexander Friedmann International Seminar on Gravitation and Cosmology, Cargese, 2004

    O perfil da indústria de laticínios na Zona da Mata e Campo das Vertentes de Minas Gerais.

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    Cenário econômico mundial; Cenário econômico brasileiro; Cenário macroeconômico regional: Zona da Mata e Campo das Vertentes; Evolução do setor lácteo brasileiro.bitstream/item/132488/1/Livro-O-perfil-da-industria-de-laticinios.pd
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