10,782 research outputs found

    Thermal treatment of superconductor thin film of the BSCCO system using domestic microwave oven

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    In this work, we report the preparation of a superconductor thin film of the BSCCO system using a good quality powder with nominal composition Bi_{1.8}Pb_{0.4}Sr_2CaCu_2O_x which was thermally treated using a domestic microwave oven (2.45 GHz, 800 W). This film was grew on a single crystal of LaAlO_3(100) substrate and exhibited a crystalline structure with the c-axis perpendicular to the plane of the substrate. An onset superconducting transition temperature was measured at 80 K.Comment: 4 pages, 5 figure

    Zinc abundances in Galactic bulge field red giants: implications for DLA systems

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    Zinc in stars is an important reference element because it is a proxy to Fe in studies of damped Lyman-alpha systems, permitting a comparison of chemical evolution histories of bulge stellar populations and DLAs. In terms of nucleosynthesis, it behaves as an alpha element because it is enhanced in metal-poor stars. The aim of this work is to derive the iron-peak element Zn abundances in 56 bulge giants from high resolution spectra. These results are compared with data from other bulge samples, as well as from disk and halo stars, and damped Lyman-alpha systems, in order to better understand the chemical evolution in these environments. High-resolution spectra were obtained using FLAMES+UVES on the Very Large Telescope. We find [Zn/Fe]=+0.24+-0.02 in the range -1.3 < [Fe/H] < -0.5 and [Zn/Fe]=+0.06+-0.02 in the range -0.5 < [Fe/H] -0.1, it shows a spread of -0.60 < [Zn/Fe] < +0.15, with most of these stars having low [Zn/Fe]<0.0. These low zinc abundances at the high metallicity end of the bulge define a decreasing trend in [Zn/Fe] with increasing metallicities. A comparison with Zn abundances in DLA systems is presented, where a dust-depletion correction was applied for both Zn and Fe. Finally, we present a chemical evolution model of Zn enrichment in massive spheroids, representing a typical classical bulge.Comment: Accepted in Astronomy & Astrophysics, in press Date of acceptance: 13/05/2015. 19 pages, 14 Figs in Astronomy & Astrophysics, 201

    Anotação de genes relacionados à tolerância a seca em arroz (Oryza sativa) de terras altas.

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    O objetivo deste trabalho foi identificar e anotar os genes expressos em resposta ao déficit hídrico em tecido foliar de duas cultivares brasileiras de arroz de terras altas, a cultivar tolerante à seca Douradão e a cultivar sensível Primavera.Apresentação oral - Pós-graduação

    Avaliação de genótipos de arroz de sequeiro para tolerância à deficiência hídrica.

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    O objetivo deste trabalho foi comparar a produtividade de três genótipos de arroz de sequeiro, submetidos a três condições de deficiência hídrica: 30 %, 50 % e 70 % do fornecimento de água dado ao tratamento controle (tratamento sem restrição de água)

    Anisotropic elastic theory of preloaded granular media

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    A macroscopic elastic description of stresses in static, preloaded granular media is derived systematically from the microscopic elasticity of individual inter-grain contacts. The assumed preloaded state and friction at contacts ensure that the network of inter-grain contacts is not altered by small perturbations. The texture of this network, set by the preparation of the system, is encoded in second and fourth order fabric tensors. A small perturbation generates both normal and tangential inter-grain forces, the latter causing grains to reorient. This reorientation response and the incremental stress are expressed in terms of the macroscopic strain.Comment: 7 pages, 2 figures. Accepted version. [email protected] [email protected]

    Effectiveness of school-based nutrition education interventions to prevent and reduce excessive weight gain in children and adolescents: a systematic review

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    OBJETIVO: Avaliar a efetividade da educação nutricional em escolas na redução ou prevenção de sobrepeso e obesidade em crianças e adolescentes. FONTES DOS DADOS: Busca sistemática em 14 bases de dados e cinco revisões sistemáticas por ensaios controlados randomizados realizados em escolas com o objetivo de reduzir ou prevenir o sobrepeso em crianças e adolescentes. O índice de massa corporal e o consumo de frutas e verduras foram utilizados como desfechos primário e secundário, respectivamente. Não houve restrição de data de publicação ou idioma, exceto para idiomas com logogramas. Excluímos estudos em populações com distúrbios alimentares, dislipidemia, diabetes e deficiência física ou mental, e que utilizassem medicamentos ou suplementos alimentares. A avaliação por título e resumo e a avaliação de qualidade foram realizadas de forma independente por dois pesquisadores. Utilizamos as orientações do Centre for Reviews and Dissemination para a elaboração de artigos de revisão em saúde e o programa EPPI-Reviewer 3. SÍNTESE DOS DADOS: Das 4.809 referências inicialmente encontradas, 24 artigos preencheram os critérios de inclusão. Os dados extraídos apresentam evidências de efeitos antropométricos positivos e de aumento no consumo de frutas e verduras. As intervenções com as seguintes características demonstraram ser efetivas: duração > 1 ano, introdução como atividade regular da escola, envolvimento dos pais, introdução da educação nutricional no currículo regular e fornecimento de frutas e verduras pelos serviços de alimentação da escola. CONCLUSÃO: As intervenções para reduzir o sobrepeso e a obesidade e aumentar o consumo de frutas e verduras foram efetivas nos estudos bem conduzidos.OBJECTIVE: To evaluate the effectiveness of school-based nutrition education in reducing or preventing overweight and obesity in children and adolescents. SOURCES: Systematic search in 14 databases and five systematic reviews for randomized controlled trials conducted in schools to reduce or prevent overweight in children and adolescents. Body mass index and fruit and vegetable intake were used as primary and secondary measures of outcome, respectively. There was no restriction by date of publication or language, except for languages with structured logograms. We excluded studies on specific populations presenting eating disorders, dyslipidemia, diabetes, and physical or mental disabilities, as well as studies that used drugs or food supplements as components of the intervention. The assessment by title and abstract and the quality assessment were performed independently by two researchers. We used the Centre for Reviews and Dissemination's guidance for undertaking reviews in health care and the software EPPI-Reviewer 3. SUMMARY OF THE FINDINGS: From the initially retrieved 4,809 references, 24 articles met the inclusion criteria. The extracted data show that there is evidence of positive effects on anthropometry and of increase in fruit and vegetable consumption. Characteristics of the interventions that demonstrated effectiveness are: duration > 1 year, introduction into the regular activities of the school, parental involvement, introduction of nutrition education into the regular curriculum, and provision of fruits and vegetables by school food services. CONCLUSION: Interventions in schools to reduce overweight and obesity, as well as to increase fruits and vegetable consumption, have demonstrated effectiveness in the best-conducted studies
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