981 research outputs found
One-loop conformal anomaly in an implicit momentum space regularization framework
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 .Comment: in European Physical Journal C, 201
Evolução da produção e do mercado mundial do feijão.
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.
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.
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.
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
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
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
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
- …