614 research outputs found

    Adaptabilidade e estabilidade produtiva em hĂ­bridos simples de sorgo granĂ­fero (Sorghum bicolor).

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    Trabalho publicado tambĂ©m no Livro de resumos do 28Âș CONGRESSO NACIONAL DE MILHO E SORGO; 4Âș SIMPÓSIO BRASILEIRO SOBRE A LAGARTA DO CARTUCHO, 2010, GoiĂąnia

    An Algebraic q-Deformed Form for Shape-Invariant Systems

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    A quantum deformed theory applicable to all shape-invariant bound-state systems is introduced by defining q-deformed ladder operators. We show these new ladder operators satisfy new q-deformed commutation relations. In this context we construct an alternative q-deformed model that preserve the shape-invariance property presented by primary system. q-deformed generalizations of Morse, Scarf, and Coulomb potentials are given as examples

    The role of clothing in thermal comfort: how people dress in a temperate and humid climate in Brazil

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    Abstract Thermal insulation from clothing is one of the most important input variables used to predict the thermal comfort of a building's occupants. This paper investigates the clothing pattern in buildings with different configurations located in a temperate and humid climate in Brazil. Occupants of two kinds of buildings (three offices and two university classrooms) assessed their thermal environment through 'right-here-right-now' questionnaires, while at the same time indoor climatic measurements were carried out in situ (air temperature and radiant temperature, air speed and humidity). A total of 5,036 votes from 1,161 occupants were collected. Results suggest that the clothing values adopted by occupants inside buildings were influenced by: 1) climate and seasons of the year; 2) different configurations and indoor thermal conditions; and 3) occupants' age and gender. Significant intergenerational and gender differences were found, which might be explained by differences in metabolic rates and fashion. The results also indicate that there is a great opportunity to exceed the clothing interval of the thermal comfort zones proposed by international standards such as ASHRAE 55 (2013) - 0.5 to 1.0 clo - and thereby save energy from cooling and heating systems, without compromising the occupants' indoor thermal comfort

    Generic properties of a quasi-one dimensional classical Wigner crystal

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    We studied the structural, dynamical properties and melting of a quasi-one-dimensional system of charged particles, interacting through a screened Coulomb potential. The ground state energy was calculated and, depending on the density and the screening length, the system crystallizes in a number of chains. As a function of the density (or the confining potential), the ground state configurations and the structural transitions between them were analyzed both by analytical and Monte Carlo calculations. The system exhibits a rich phase diagram at zero temperature with continuous and discontinuous structural transitions. We calculated the normal modes of the Wigner crystal and the magneto-phonons when an external constant magnetic field BB is applied. At finite temperature the melting of the system was studied via Monte Carlo simulations using the modifiedmodified LindemannLindemann criterioncriterion (MLC). The melting temperature as a function of the density was obtained for different screening parameters. Reentrant melting as a function of the density was found as well as evidence of directional dependent melting. The single chain regime exhibits anomalous melting temperatures according to the MLC and as a check we study the pair correlation function at different densities and different temperatures, formulating a different criterion. Possible connection with recent theoretical and experimental results are discussed and experiments are proposed.Comment: 13 pages text, 21 picture

    Plantando, colhendo, vendendo, mas nĂŁo comendo: prĂĄticas alimentares e de trabalho associadas Ă  obesidade em agricultores familiares do Bonfim, PetrĂłpolis, RJ.

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    Objetivo: verificar a prevalĂȘncia de obesidade entre adultos das 86 famĂ­lias agricultoras de um bairro de PetrĂłpolis, RJ, e analisar seus determinantes socioculturais. MĂ©todos: estudo quantitativo e qualitativo sobre nutrição, prĂĄticas alimentares e de trabalho realizado em 2008. Dados antropomĂ©tricos foram coletados por inquĂ©rito nutricional domiciliar e o material qualitativo por observação participante e entrevistas. Resultados: a prevalĂȘncia de obesidade foi baixa (9,3%) entre os homens, mas bastante elevada entre as mulheres (29,9%). A prĂĄtica agrĂ­cola local implica em atividade fĂ­sica leve para mulheres e intensa para homens. Essa diferença nĂŁo Ă© acompanhada na dieta, semelhante para homens e mulheres, com predomĂ­nio de alimentos de alto valor calĂłrico. A produção familiar objetiva essencialmente a venda. A agricultura mercantil e a decorrente especialização dos cultivos favorecem comprar alimentos no mercado em vez de produzir para autoconsumo. ConclusĂŁo: os aspectos socioculturais e ocupacionais estudados podem ter contribuĂ­do para elevar a prevalĂȘncia de obesidade nas mulheres e podem ser Ășteis no estudo de outros grupos com caracterĂ­sticas semelhantes. Esta pesquisa ratifica a importĂąncia de estudar a obesidade em nĂ­vel local, integrando abordagens quantitativas e qualitativas para identificar possĂ­veis limitaçÔes e portas de entrada para açÔes de intervenção localmente relevantes

    Effect of different gonadotropins on in vitro maturation of sheep oocytes.

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    The aim of this study was to examine the effect of replacing the use of follicle-stimulating hormone (FSH) with equine chorionic gonadotropin (eCG) and human chorionic gonadotropin (hCG) on the in vitro maturation (IVM) of sheep oocytes. After sheep ovaries were collected (n=300), the cumulus-oocyte complexes were aspirated, selected, and divided into four groups according to the IVM medium: CON group, in which the basic IVM medium was used; and eCG, hCG, and FSH groups, in which the oocytes were immersed in basic IVM medium with 10 IU/mL eCG, 10 IU/mL hCG, and 10 Όg/mL FSH-p, respectively. In vitro maturation of the oocytes was performed at 38.5 °C, in a humidified atmosphere of 5% CO2 in air, for 24 h. Subsequently, the oocytes were evaluated for the degree of cumulus-cell expansion, chromatin configuration, GSH levels, and active mitochondria. There were no significant differences for the rate of cumulus cell expansion. The percentage of oocytes in MII was higher in the eCG group than in the CON and hCG groups (P<0.05) and similar to that of the FSH group. In conclusion, eCG can be used as a substitute for FSH in IVM of sheep oocytes
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