18,107 research outputs found

    Predicted defect induced vortex core switching in thin magnetic nanodisks

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    We investigate the influence of artificial defects (small holes) inserted into magnetic nanodisks on the vortex core dynamics. One and two holes (antidots) are considered. In general, the core falls into the hole but, in particular, we would like to remark an interesting phenomenon not yet observed, which is the vortex core switching induced by the vortex-hole interactions. It occurs for the case with only one hole and for very special conditions involving the hole size and position as well as the disk size. Any small deformation in the disk geometry such as the presence of a second antidot changes completely the vortex dynamics and the vortex core eventually falls into one of the defects. After trapped, the vortex center still oscillates with a very high frequency and small amplitude around the defect center.Comment: 11pages, Revtex format, 17 figure

    Speeding Up Computer Simulations: The Transition Observable Method

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    A method is presented which allows for a tremendous speed-up of computer simulations of statistical systems by orders of magnitude. This speed-up is achieved by means of a new observable, while the algorithm of the simulation remains unchanged.Comment: 20 pages, 6 figures Submitted to Phys.Rev.E (August 1999) Replacement due to some minor change

    The use of linoleic acid in in vitro culture of bovine embryos and its effects on production and survival to vitrification.

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    Proceedings of the 31st Annual Meeting of the Brazilian Embryo Technology Society (SBTE); Cabo de Santo Agostinho, PE, Brazil, August 17th to 19th, 2017. Abstracts

    Evaluation of L-carnitine supplementation on the production and vitrification of bovine embryos produced in vitro.

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    Proceedings of the 31st Annual Meeting of the Brazilian Embryo Technology Society (SBTE); Cabo de Santo Agostinho, PE, Brazil, August 17th to 19th, 2017. Abstracts

    Aspectos estruturais e funcionais de quintais agroflorestais em propriedades de agricultores familiares no Nordeste paraense.

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    Neste trabalho identificou-se a diversidade de espécies vegetais e animais, e seus usos em quintais agroflorestais situados em propriedades de agricultores familiares no Nordeste Paraense. O estudo foi desenvolvido no âmbito do projeto ?Conservação e recuperação de áreas degradadas em unidades de produção agrícola familiar na Amazônia Oriental Brasileira - INOVAGRI?, financiado pela Organização Internacional de Madeira Tropical ? OIMT. As informações foram coletadas por meio de entrevista semi-estruturada, travessia de quintais, observação direta e registro fotográfico. Foram identificadas 120 espécies vegetais e quatro animais, pertencentes a 61 famílias. Sobre as espécies vegetais, observou-se que 55 (45%) são de uso alimentar, 28 (23%) medicinais e 37 (30%) ornamentais, destacando-se as famílias Araceae (8 espécies), Rutaceae (7), e Anacardiaceae (5). As frutíferas representam 32% do total das espécies cultivadas nos quintais, o que demonstra a sua importância na segurança alimentar das famílias.Editores técnicos: Roberto Porro, Milton Kanashiro, Maria do Socorro Gonçalves Ferreira, Leila Sobral Sampaio e Gladys Ferreira de Sousa

    2-(2-methyl-2-nitrovinyl)furan but not furvina interfere with staphylococcus aureus agr quorum-sensing system and potentiate the action of fusidic acid against biofilms

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    Quorum sensing (QS) plays an essential role in the production of virulence factors, in biofilm formation and antimicrobial resistance. Consequently, inhibiting QS is being consid-ered a promising target for antipathogenic/anti-virulence therapies. This study aims to screen 2-nitrovinylfuran derivatives structurally related to Furvina (a broad-spectrum antibiotic already used for therapeutic purposes) for their effects on QS and in biofilm prevention/control. Furvina and four 2-nitrovinylfuran derivatives (compounds 1–4) were tested to assess the ability to interfere with QS of Staphylococcus aureus using bioreporter strains (S. aureus ALC1742 and ALC1743). The activity of Furvina and the most promising quorum-sensing inhibitor (QSI) was evaluated in biofilm prevention and in biofilm control (combined with fusidic acid). The biofilms were further characterized in terms of biofilm mass, viability and membrane integrity. Compound 2 caused the most significant QS inhibition with reductions between 60% and 80%. Molecular docking simulations indicate that this compound interacts preferentially with the protein hydrophobic cleft in the LytTR domain of AgrA pocket. Metabolic inactivations of 40% for S. aureus ALC1742 and 20% for S. aureus ALC1743 were reached. A 24 h-old biofilm formed in the presence of the QSI increased the metabolic inactivation by fusidic acid to 80%, for both strains. The overall results highlight the effects of compound 2 as well as the potential of combining QSI with in-use antibiotics for the management of skin and soft tissues infections

    Espaços digitais de informação e comunicação: Agência Embrapa de Informação Tecnológica para dispositivos móveis.

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    O artigo analisa e propõe a incorporação de dispositivos móveis na organização e acesso de espaços digitais de informação e comunicação na Web. Admite-se que as mídias móveis tendem a ser amplamente adotadas por todos os segmentos da sociedade, inclusive no meio rural. Parte-se da experiência do website da Agência Embrapa de Informação Tecnológica (AGEITEC), que se constitui em um espaço digital para acesso via desktop, e propõe: a) o estabelecimento de uma metodologia de organização de conteúdos atinentes ao conceito de Web 2.0 móvel, destinados a apoiar ações comunicacionais em processos de transferência de tecnologia; b) a criação da AGEITEC Móvel (mAGEITEC), incorporando funcionalidades e ferramentas da Web 2.0 móvel. O artigo traz contribuições metodológicas e tecnológicas que podem subsidiar a elaboração de projetos de pesquisa no âmbito da criação de espaços digitais dedicados ao atendimento das necessidades de informação e comunicação de pessoas em mobilidade.ALAIC 2014
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