34,094 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
The Redner - Ben-Avraham - Kahng cluster system
We consider a coagulation model first introduced by Redner, Ben-Avraham and
Krapivsky in [Redner, Ben-Avraham, Kahng: Kinetics of 'cluster eating', J.
Phys. A: Math. Gen., 20 (1987), 1231-1238], the main feature of which is that
the reaction between a j-cluster and a k-cluster results in the creation of a
|j-k|-cluster, and not, as in Smoluchowski's model, of a (j+k)-cluster. In this
paper we prove existence and uniqueness of solutions under reasonably general
conditions on the coagulation coefficients, and we also establish
differenciability properties and continuous dependence of solutions. Some
interesting invariance properties are also proved. Finally, we study the
long-time behaviour of solutions, and also present a preliminary analysis of
their scaling behaviour.Comment: 24 pages. 2 figures. Dedicated to Carlos Rocha and Luis Magalhaes on
the occasion of their sixtieth birthday
The Redner - Ben-Avraham - Kahng coagulation system with constant coefficients: the finite dimensional case
We study the behaviour as of solutions to the
Redner--Ben-Avraham--Kahng coagulation system with positive and compactly
supported initial data, rigorously proving and slightly extending results
originally established in [4] by means of formal arguments.Comment: 13 pages, 1 figur
Uso sustentável da água.
A Embrapa tem priorizado estudos sobre o uso sustentável da água e do solo e sobre a recuperação de APPs, cujo objetivo é propor medidas de manejo e ações mitigadoras, visando à recuperação e à reabilitação das áreas impactadas. Estas ações, se bem executadas, podem resultar em maior controle da poluição e melhor qualidade da água e do ambiente.bitstream/item/126573/1/Uso-sustentavel-da-agua.pd
In-medium formation of quarkonium
We confront preliminary RHIC data on J/Psi production in nuclear interactions
with expectations which follow in scenarios involving charm quark recombination
in a region of color deconfinement. The focus is on transverse momentum and
rapidity spectra of the J/Psi, which carry a memory of the spectra of the charm
quarks. In such a scenario, one predicts that both spectra will be narrower
than those expected without recombination. Preliminary results for the
transverse momentum spectra point toward a preference for the recombination
picture, while the rapidity spectra do not exhibit any narrowing within present
large uncertainties. We present new calculations in the recombination model for
the centrality behavior of these signals, which map out the necessary
experimental precision required for a definitive test.Comment: Based on invited talk at Strangeness in Quark Matter 2006, UCLA,
March 26-31, 2006. Clarifying remarks added in published journal versio
Metodologia científica para extração de DNA de amostras de sangue (aves e quelônios).
bitstream/item/56378/1/ComTec228.pd
Práticas de manejo em capoeiras de pequenas propriedades em processo de transição agroecológica na zona rural de Manaus-AM.
Práticas de manejo em capoeiras de pequenas propriedades em processo de transição agroecológica na zona rural de Manaus-AM
Variabilidade patogênica e resistência genética no patossistema milho - Colletotrichum graminicola.
Suplemento. Edição dos Resumos do XLI Congresso Brasileiro de Fitopatologia, Belo Horizonte, MG, ago. 2008
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