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

Poda em cafeeiro Robusta.

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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