981 research outputs found

    One-loop conformal anomaly in an implicit momentum space regularization framework

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    In this paper we consider matter fields in a gravitational background in order to compute the breaking of the conformal current at one-loop order. Standard perturbative calculations of conformal symmetry breaking expressed by the non-zero trace of the energy-momentum tensor have shown that some violating terms are regularization dependent, which may suggest the existence of spurious breaking terms in the anomaly. Therefore, we perform the calculation in a momentum space regularization framework in which regularization dependent terms are judiciously parametrized. We compare our results with those obtained in the literature and conclude that there is an unavoidable arbitrariness in the anomalous term R\Box R.Comment: in European Physical Journal C, 201

    Evolução da produção e do mercado mundial do feijão.

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    Realizou-se uma avaliação do mercado internacional de feijão, considerando produção, exportação e importação, mostrando o comportamento e oscilações dos principais países

    Brazil nut almonds: nutritional and market aspects.

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    The aim of this study was to estimate the annual growth rate in production and exportation of Brazil nut almonds. Presents information related to the composition of different fatty acids from brazil nut almonds and the human daily intake needs, as well as an analysis of its production, its growth rate during the last 20 years and its export. and the human daily intake needs

    Consumo, valor nutritivo e evolução da produção e de mercado mundial de feijão.

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    Apresentado Painel na 6º Semana de Ensino, Pesquisa e Extensão Universidade Federal de Santa Catarina

    Uso de séries temporais no estudo do mercado de trigo.

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    Existem diversas metodologias com base em dados de séries temporais aplicáveis a estudos de modelos de previsão. Com o intuito de analisar a evolução do mercado de trigo foram utilizados dois desses modelos, Arima e Espaço de Estados, para previsão das séries: produção, consumo e importação de trigo do Brasil. As séries observadas compreendem o período 1972- 2008 e as previsões se estendem até 2018. Taxas de crescimento também foram calculadas para as séries analisadas. Os resultados obtidos mostram que as projeções da produção e da importação foram as que melhor se ajustaram aos dados. As estimativas indicam perspectivas de crescimento para a produção, o consumo e a importação de trigo. A maior taxa de crescimento foi encontrada para a produção. Conclui-se que o Brasil não conseguirá se tornar auto-suficiente na produção de trigo, mantendo sua dependência em relação aos mercados exportadores, uma vez que o consumo continuará aumentando

    Non-planar snake gaits: from Stigmatic-starts to Sidewinding

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    Of the vast variety of animal gaits, one of the most striking is the non-planar undulating helical motion of a sidewinder. But non-planar helical gaits are not limited to sidewinders. Here we report a new non-planar gait used as an escape strategy in juvenile anacondas (Eunectes notaeus). In the S(tigmatic)-start, named for its eponymous shape, transient locomotion arises when the snake writhes and bends out of the plane while rolling forward about its midsection without slippage. We present a mathematical model for an active non-planar filament that interacts anisotropically with a frictional substrate to quantify our observations and show that locomotion is due to a propagating localized pulse of a topological quantity, the link density. A phase diagram as a function of scaled body size and muscular torques shows that relatively light juveniles are capable of S-starts but heavy adults are not, consistent with our experimental observations. We further show theoretically that a periodic sequence of S-starts naturally leads to sidewinding. All together, our characterization of a novel escape strategy in snakes using non-planar gaits highlights the role of topology in locomotion, provides a phase diagram for gait feasibility as a function of body size, and shows that the S-start forms the fundamental kernel underlying sidewinding

    Giant congenital melanocytic naevi: review of literature

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    giant congenital pigmented naevi is a great reconstructive challenge for the pediatric and plastic surgeons. due to the increased risk of malignant transformation in such lesions, many procedures have been used to remove giant congenital naevi like dermoabrasion, laser treatment or surgical excision combined with reconstruction through skin expansion or skin grafting; among these, only a complete excision can offer an efficacious treatment. in our centre we use the "tissue expansion" technique in order to achieve a sufficient quantity of normal skin to perform a both staged and radical excision of these giant lesions

    Nature versus Nurture: The curved spine of the galaxy cluster X-ray luminosity -- temperature relation

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    The physical processes that define the spine of the galaxy cluster X-ray luminosity -- temperature (L-T) relation are investigated using a large hydrodynamical simulation of the Universe. This simulation models the same volume and phases as the Millennium Simulation and has a linear extent of 500 h^{-1} Mpc. We demonstrate that mergers typically boost a cluster along but also slightly below the L-T relation. Due to this boost we expect that all of the very brightest clusters will be near the peak of a merger. Objects from near the top of the L-T relation tend to have assembled much of their mass earlier than an average halo of similar final mass. Conversely, objects from the bottom of the relation are often experiencing an ongoing or recent merger.Comment: 8 pages, 7 figures, submitted to MNRA
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