632 research outputs found
Propagação vegetativa por estaquia de espécies/procedências de Eucalyptus.
bitstream/item/101179/1/PA-1983-Higa-PropagacaoVegetativa.pd
Scalar form factors and nuclear interactions
The scalar-isoscalar term in the two-pion exchange potential is
abnormally large and does not respect the hierarchy of effects predicted by
chiral perturbation theory. We argue that this anomaly is associated with
non-perturbative effects, which are also present in the scalar form
factor.Comment: Talk given at the 20EFB, Pisa, Italy, September 2007. 3 pages and 4
figure
The rate of convergence of Euler approximations for solutions of stochastic differential equations driven by fractional Brownian motion
The paper focuses on discrete-type approximations of solutions to
non-homogeneous stochastic differential equations (SDEs) involving fractional
Brownian motion (fBm). We prove that the rate of convergence for Euler
approximations of solutions of pathwise SDEs driven by fBm with Hurst index
can be estimated by ( is the diameter of
partition). For discrete-time approximations of Skorohod-type quasilinear
equation driven by fBm we prove that the rate of convergence is .Comment: 21 pages, (incorrect) weak convergence result removed, to appear in
Stochastic
Amostragem de indivíduos representativos em uma população de animais da raça Canchim aparentados e genotipados.
O objetivo neste estudo foi avaliar diferentes métodos para selecionar uma amostra de uma população contendo animais aparentados, representando estratos de famílias, de forma que os animais selecionados representem toda a população. Utilizaram-se duas fontes de informação para o estudo. A primeira foi o arquivo de pedigree (animal, pai e mãe) constituído de 6.801 animais da raça Canchim, sendo 400 animais genotipados . A segunda foi a matriz de parentesco constituída pelos coeficientes de parentesco dos 400 animais genotipados, organizados na forma de matriz, com os animais nas linhas e colunas e os correspondentes coeficientes de parentesco dentro da matriz (BOURDON, 2000)
Unidades de manejo para Pinus taeda L. com base na análise de agrupamento.
Seção: Silvicultura e Produção de Biomassa
Electric Dipole Moments of Light Nuclei From Chiral Effective Field Theory
We set up the framework for the calculation of electric dipole moments (EDMs)
of light nuclei using the systematic expansion provided by chiral effective
field theory (EFT). We take into account parity (P) and time-reversal (T)
violation which, at the quark-gluon level, originates from the QCD vacuum angle
and dimension-six operators capturing physics beyond the Standard Model. We
argue that EDMs of light nuclei can be expressed in terms of six low-energy
constants that appear in the P- and T-violating nuclear potential and electric
current. As examples, we calculate the EDMs of the deuteron, the triton, and
3He in leading order in the EFT expansion
Tidal disruption of satellites and formation of narrow rings
In this paper we investigate the formation of narrow planetary rings such as
those found around Uranus and Saturn through the tidal disruption of a weak,
gravitationally bound satellite that migrates within its Roche limit. Using
-body simulations, we study the behaviour of rubble piles placed on circular
orbits at different distances from a central planet. We consider both
homogeneous satellites and differentiated bodies containing a denser core. We
show that the Roche limit for a rubble pile is closer to the planet than for a
fluid body of the same mean density. The Roche limit for a differentiated body
is also closer to the planet than for a homogeneous satellite of the same mean
density. Within its Roche limit, a homogeneous satellite totally disrupts and
forms a narrow ring. The initial stages of the disruption are similar to the
evolution of a viscous fluid ellipsoid, which can be computed
semi-analytically. On the other hand, when a differentiated satellite is just
within the Roche limit only the mantle is disrupted. This process is similar to
Roche-lobe overflow in interacting binary stars and produces two narrow rings
on either side of a remnant satellite. We argue that the Uranian rings, and
possibly their shepherd satellites, could have been formed through the tidal
disruption of a number of protomoons that were formed inside the corotation
radius of Uranus and migrated slowly inwards as a result of tidal interaction
with the planet.Comment: Accepted for publication in MNRAS. Some figures have been compressed
to fit into astro-ph size guidelines. Please contact authors if full
resolution images are require
Estudo de algoritmos de biclustering para a análise de expressão gênica utilizando atecnologia de microarranjo.
A tecnologia de microarranjo permite que as expressões gênicas de um grande número de genes sejam simultaneamente avaliadas em diferentes condições, que formam amostras observadas sobre elas. As condições podem corresponder a diferentes pontos no tempo, tecidos, condições experimentais ou condições ambientais. Um passo crucial na análise desse tipo de dado é a extração de informações biologicamente relevantes. Em geral, dados de expressão gênica são organizados em uma matriz, onde cada linha corresponde a um gene e cada coluna a uma condição. Cada elemento dessa matriz contém um número real que reflete o logaritmo da abundância relativa de mRNA de um determinado gene sob uma condição específica.bitstream/item/32428/1/doc109.pd
- …