26,136 research outputs found
Fast Community Identification by Hierarchical Growth
A new method for community identification is proposed which is founded on the
analysis of successive neighborhoods, reached through hierarchical growth from
a starting vertex, and on the definition of communities as a subgraph whose
number of inner connections is larger than outer connections. In order to
determine the precision and speed of the method, it is compared with one of the
most popular community identification approaches, namely Girvan and Newman's
algorithm. Although the hierarchical growth method is not as precise as Girvan
and Newman's method, it is potentially faster than most community finding
algorithms.Comment: 6 pages, 5 figure
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
Controle de podridões-radiculares na cultura do feijoeiro: eficácia da aplicação de fungicidas no sulco de plantio.
O controle de podridões-radiculares via tratamento de sementes tem sido errático, com históricos de sucesso e insucesso em diversas regiões produtoras de feijão. A pulverização de fungicidas no sulco de plantio, já utilizada em outras culturas, como o algodão e a batata, surge como alternativa a este tratamento padrão. Por este motivo, diversos fungicidas foram testados quanto a sua eficiência no controle de podridões radiculares via pulverização no sulco de plantio do feijoeiro.bitstream/CNPAF/19135/1/doc_118.pdfConvênio: Embrapa Arroz e Feijão e Hokko do Brasil
Compatibilidade de fungicidas e inseticidas no tratamento de sementes do feijoeiro (Phaseolus vulgaris L.) associadas ou não a polímeros: relatório técnico.
Tratamento de sementes do feijoeiro com inseticida; Revestimento de sementes do feijoeiro tratadas com inseticidas e fungicidas; Experimento I - Qualidade fisiológica e sanitária; Experimento II - Teste de campo; Experimento III - Avaliação da eficiência de controle de adultos da mosca branca, Bemisia argentifolii; Conclusão; Referências bibliográficas; Anexos..bitstream/CNPAF/19141/1/doc_125.pdfCooperação técnica: Embrapa Arroz e Feijão & Bayer S/A
Efeito da mistura de fungicidas aplicados via fungigação no controle do mofo-branco do feijoeiro comum.
Procurando otimizar a eficácia de controle, este trabalho objetivou determinar o efeito preventivo e residual de fungicidas utilizados em mistura e aplicados via fungigação para o controle do mofo-branco do feijoeiro.bitstream/CNPAF/19129/1/pqfoco62.pd
PAIRWISE VELOCITIES OF GALAXIES IN THE CFA AND SSRS2 REDSHIFT SURVEYS
(compressed version) We combine the CfA Redshift Survey (CfA2) and the
Southern Sky Redshift Survey (SSRS2) to estimate the pairwise velocity
dispersion of galaxies \sig12 on a scale of \sim 1 \hmpc. Both surveys are
complete to an apparent magnitude limit . Our sample includes 12,812
galaxies distributed in a volume 1.8 \times 10^6 \hmpc3. We conclude: 1) The
pairwise velocity dispersion of galaxies in the combined CfA2+SSRS2 redshift
survey is \sig12=540 \kms \pm 180 \kms. Both the estimate and the variance of
\sig12 significantly exceed the canonical values \sig12=340 \pm40 measured
by Davis \& Peebles (1983) using CfA1. 2) We derive the uncertainty in \sig12
from the variation among subsamples with volumes on the order of \hmpc3. This variation is nearly an order of magnitude larger than the
formal error, 36 \kms, derived using least-squares fits to the CfA2+SSRS2
correlation function. This variation among samples is consistent with the
conclusions of Mo \etal (1993) for a number of smaller surveys and with the
analysis of CfA1 by Zurek \etal (1994). 3) When we remove Abell clusters with
from our sample, the pairwise velocity dispersion of the remaining
galaxies drops to 295 \pm 99 \kms. Thus the dominant source of variance in
\sig12 is the shot noise contributed by dense virialized systems. 4) The
distribution of pairwise velocities is consistent with an isotropic exponential
with velocity dispersion independent of scale.Comment: 61 pages uuencoded, compressed postscript in 5 pieces. Also available
in one piece at http://www.dao.nrc.ca/DAO/SCIENCE/science.htm
An embedded formulation with conforming
Use of strong discontinuities with satisfaction of compatibilit
The Power Spectrum of Galaxies in the Nearby Universe
We compute the power spectrum of galaxy density fluctuations in a recently
completed redshift survey of optically-selected galaxies in the southern
hemisphere (SSRS2). The amplitude and shape of the SSRS2 power spectrum are
consistent with results of the Center for Astrophysics redshift survey of the
northern hemisphere (CfA2), including the abrupt change of slope on a scale of
30-50Mpc/h; these results are reproducible for independent volumes of space and
variations are consistent with the errors estimated from mock surveys. Taken
together, the SSRS2 and CfA2 form a complete sample of 14,383 galaxies which
covers one-third of the sky. The power spectrum of this larger sample continues
to rise on scales up to ~ 200Mpc/h, with weak evidence for flattening on the
largest scales. The SSRS2+CfA2 power spectrum and the power spectrum
constraints implied by COBE are well-matched by an Omega*h ~ 0.2,
Omega+lambda_0=1 CDM model with minimal biasing of optically-selected galaxies.Comment: Accepted for publication in The Astrophysical Journal Letters, Sept.
23, 1994. 10 pages uuencoded compressed postscript, including two figures.
JHU-9410200
Efeito da calagem, adubação fosfatada e potássica no estabelecimento de Leucaena leucocephala.
O objetivo do estudo foi o efeito da aplicacao, no sulco de plantio de calcario dolomitico de superfosfato simples e cloreto de potassio de Leucaena leucocephala.Resum
The complex channel networks of bone structure
Bone structure in mammals involves a complex network of channels (Havers and
Volkmann channels) required to nourish the bone marrow cells. This work
describes how three-dimensional reconstructions of such systems can be obtained
and represented in terms of complex networks. Three important findings are
reported: (i) the fact that the channel branching density resembles a power law
implies the existence of distribution hubs; (ii) the conditional node degree
density indicates a clear tendency of connection between nodes with degrees 2
and 4; and (iii) the application of the recently introduced concept of
hierarchical clustering coefficient allows the identification of typical scales
of channel redistribution. A series of important biological insights is drawn
and discussedComment: 3 pages, 1 figure, The following article has been submitted to
Applied Physics Letters. If it is published, it will be found online at
http://apl.aip.org
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