4,424 research outputs found
The evolution of Giant Molecular Filaments
In recent years there has been a growing interest in studying giant molecular
filaments (GMFs), which are extremely elongated (> 100pc in length) giant
molecular clouds (GMCs). They are often seen as inter-arm features in external
spiral galaxies, but have been tentatively associated with spiral arms when
viewed in the Milky Way. In this paper, we study the time evolution of GMFs in
a high-resolution section of a spiral galaxy simulation, and their link with
spiral arm GMCs and star formation, over a period of 11Myrs. The GMFs generally
survive the inter-arm passage, although they are subject to a number of
processes (e.g. star formation, stellar feedback and differential rotation)
which can break the giant filamentary structure into smaller sections. The GMFs
are not gravitationally bound clouds as a whole, but are, to some extent,
confined by external pressure. Once they reach the spiral arms, the GMFs tend
to evolve into more substructured spiral arm GMCs, suggesting that GMFs may be
precursors to arm GMCs. Here, they become incorporated into the more complex
and almost continuum molecular medium that makes up the gaseous spiral arm.
Instead of retaining a clear filamentary shape, their shapes are distorted both
by their climb up the spiral potential and their interaction with the gas
within the spiral arm. The GMFs do tend to become aligned with the spiral arms
just before they enter them (when they reach the minimum of the spiral
potential), which could account for the observations of GMFs in the Milky Way.Comment: 15 pages, 11 figures, MNRAS accepte
Tendências na aplicação de tecnologia de membranas no processamento de frutas tropicais.
Resumo das palestras
Conductivity of Coulomb interacting massless Dirac particles in graphene: Regularization-dependent parameters and symmetry constraints
We compute the Coulomb correction to the a. c. conductivity of
interacting massless Dirac particles in graphene in the collisionless limit
using the polarization tensor approach in a regularization independent
framework. Arbitrary parameters stemming from differences between
logarithmically divergent integrals are fixed on physical grounds exploiting
only spatial rotational invariance of the model which amounts to
transversality of the polarization tensor. Consequently is
unequivocally determined to be within this effective model. We
compare our result with explicit regularizations and discuss the origin of
others results for found in the literature
Otimização do processo de descascamento de soja utilizando descascador de discos paralelos horizontais.
bitstream/item/67908/1/CT-43-.pd
Manual de produção artesanal de soja frita.
Introdução. Definição de soja frita (soynuts). Fluxograma de produção. Descrição do processo. Embalagem. Referências bibliográficas.bitstream/item/78987/1/doc66-2005.pd
CaracterÃsticas do grão de algumas linhagens de soja de tegumento colorido.
bitstream/item/65447/1/CTAA-DOCUMENTOS-17-CARACTERISTICAS-DO-GRAO-DE-ALGUMAS-LINHAGENS-DE-SOJA-DE-TEGUMENTO-COLORIDO-FL-.pd
Structural Changes in Data Communication in Wireless Sensor Networks
Wireless sensor networks are an important technology for making distributed
autonomous measures in hostile or inaccessible environments. Among the
challenges they pose, the way data travel among them is a relevant issue since
their structure is quite dynamic. The operational topology of such devices can
often be described by complex networks. In this work, we assess the variation
of measures commonly employed in the complex networks literature applied to
wireless sensor networks. Four data communication strategies were considered:
geometric, random, small-world, and scale-free models, along with the shortest
path length measure. The sensitivity of this measure was analyzed with respect
to the following perturbations: insertion and removal of nodes in the geometric
strategy; and insertion, removal and rewiring of links in the other models. The
assessment was performed using the normalized Kullback-Leibler divergence and
Hellinger distance quantifiers, both deriving from the Information Theory
framework. The results reveal that the shortest path length is sensitive to
perturbations.Comment: 12 pages, 4 figures, Central European Journal of Physic
Soja na alimentação humana.
CaracterÃsticas fÃsicas, composição quÃmica e valor nutritivo. Obtenção e uso dos principais produtos de soja. Produtos não desengordurados. Produtos do óleo bruto. Produtos do farelo desengordurado cru. Produtos de tradição oriental.bitstream/item/65355/1/CTAA-DOCUMENTOS-01-SOJA-NA-ALIMENTACAO-HUMANA-LV-2005-00497.pd
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