27,241 research outputs found
A Fast and Accurate Nonlinear Spectral Method for Image Recognition and Registration
This article addresses the problem of two- and higher dimensional pattern
matching, i.e. the identification of instances of a template within a larger
signal space, which is a form of registration. Unlike traditional correlation,
we aim at obtaining more selective matchings by considering more strict
comparisons of gray-level intensity. In order to achieve fast matching, a
nonlinear thresholded version of the fast Fourier transform is applied to a
gray-level decomposition of the original 2D image. The potential of the method
is substantiated with respect to real data involving the selective
identification of neuronal cell bodies in gray-level images.Comment: 4 pages, 3 figure
Alternativas Agroecológicas de Manejo de Plantas Daninhas no Cafezal em Rondônia.
Esta publicação apresenta algumas formas de plantio de café, testadas pela Embrapa Rondônia, na perspectiva de se obter um melhor resultado para o controle de invasores prejuciais à cafeicultura do Estado de RO.bitstream/item/24790/1/folder-manejocafezal.pd
Growth-Driven Percolations: The Dynamics of Community Formation in Neuronal Systems
The quintessential property of neuronal systems is their intensive patterns
of selective synaptic connections. The current work describes a physics-based
approach to neuronal shape modeling and synthesis and its consideration for the
simulation of neuronal development and the formation of neuronal communities.
Starting from images of real neurons, geometrical measurements are obtained and
used to construct probabilistic models which can be subsequently sampled in
order to produce morphologically realistic neuronal cells. Such cells are
progressively grown while monitoring their connections along time, which are
analysed in terms of percolation concepts. However, unlike traditional
percolation, the critical point is verified along the growth stages, not the
density of cells, which remains constant throughout the neuronal growth
dynamics. It is shown, through simulations, that growing beta cells tend to
reach percolation sooner than the alpha counterparts with the same diameter.
Also, the percolation becomes more abrupt for higher densities of cells, being
markedly sharper for the beta cells.Comment: 8 pages, 10 figure
Registro de introduções de plantas de cultura pré-colombiana coletadas na Amazônia brasileira.
Registro de introduções do material coletado nas viagens realizadas de 1984 a 1988. Principais características das plantas matrizes: timbó, dao, acai, tucuma, cupuaçu, biriba, condessa, graviola, araticum, palmeiras do gênero oenocarpus, pupunha, urucu, taperebá, cutite, cajarana, cacau, plantas medicinais, boldo.bitstream/item/63464/1/CPATU-Doc58.pd
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