7,577 research outputs found
Mineração de textos aplicada à análise de dados de expressão gênica por microarranjos.
Este trabalho se insere no projeto "Rede Genômica Animal" e tem por objetivo construir uma ferramenta que utilize técnicas de mineração de textos para apoiar a interpretação biológica de dados de experimentos de expressão gênica. Por isso, os dados de expressão gênica a serem utilizados para validação da ferramenta são aqueles gerados no escopo do projeto "Rede Genômica Animal", referente ao organismo Bos taurus
Eutils-search - manual do usuário.
O software Eutils-search tem por objetivo trazer do banco de dados PubMed informações sobre artigos relacionados a genes de um organismo específico, de acordo com as regras referentes à taxa de acesso impostas pelo site. As informações trazidas são, então, armazenadas localmente em um banco de dados para acesso rápido. Além disso, o software também gera documentos XML correspondentes às informações do organismo requisitado. O eutils-search é uma ferramenta de apoio ao desenvolvimento de aplicações de mineração de textos voltadas para os domínios de biotecnologia e biologia molecular, baseada em informações textuais obtidas do banco de dados PubMed. Este documento apresenta os pré-requisitos e a descrição dos parâmetros necessários para utilização do software, bem como uma descrição de alguns aspectos internos do software, para melhor entendimento do processo que ele automatiza, além de alguns exemplos e uso.bitstream/item/31573/1/doc106-10.pd
Spontaneous alloying in binary metal microclusters - A molecular dynamics study -
Microcanonical molecular dynamics study of the spontaneous alloying(SA),
which is a manifestation of fast atomic diffusion in a nano-sized metal
cluster, is done in terms of a simple two dimensional binary Morse model.
Important features observed by Yasuda and Mori are well reproduced in our
simulation. The temperature dependence and size dependence of the SA phenomena
are extensively explored by examining long time dynamics. The dominant role of
negative heat of solution in completing the SA is also discussed. We point out
that a presence of melting surface induces the diffusion of core atoms even if
they are solid-like. In other words, the {\it surface melting} at substantially
low temperature plays a key role in attaining the SA.Comment: 15 pages, 12 fgures, Submitted to Phys.Rev.
Lifetime measurement of the ^3P_2 metastable state of strontium atoms
We have measured the lifetime of the 5s5p ^3P_2 metastable state of strontium
atoms by magneto-optically trapping the decayed atoms to the ground state,
which allowed sensitive detection of the rare decay events. We found that the
blackbody radiation-induced decay was the dominant decay channel for the state
at T = 300 K. The lifetime was determined to be 500^{+280}_{-130} s in the
limit of zero temperature.Comment: 4 pages, 3 figures, submitted to Physical Review Letter
The performance of thin NaI(Tl) scintillator plate for dark matter search
A thin (0.05cm) and wide area (5cmX5cm) NaI(Tl) scintillator was developed.
The performance of the thin NaI(Tl) plate, energy resolution, single
photoelectron energy and position sensitivity were tested. An excellent energy
resolution of 20% (FWHM) at 60keV was obtained. The single photoelectron energy
was calculated to be approximately 0.42 0.02keV. Position information in the
5cmx5cm area of the detector was also obtained by analyzing the ratio of the
number of photons collected at opposite ends of the detector. The position
resolution was obtained to be 1cm (FWHM) in the 5cmx5cm area.Comment: 10 pages. Accepted to Journal of Physical Society of Japa
Bond-Dilution-Induced Quantum Phase Transitions in Heisenberg Antiferromagnets
Bond-dilution effects on the ground state of the square-lattice
antiferromagnetic Heisenberg model, consisting of coupled bond-alternating
chains, are investigated by means of the quantum Monte Carlo simulation. It is
found that, when the ground state of the non-diluted system is a non-magnetic
state with a finite spin gap, a sufficiently weak bond dilution induces a
disordered state with a mid gap in the original spin gap, and under a further
stronger bond dilution an antiferromagnetic long-range order emerges. While the
site-dilution-induced long-range order is induced by an infinitesimal
concentration of dilution, there exists a finite critical concentration in the
case of bond dilution. We argue that this essential difference is due to the
occurrence of two types of effective interactions between induced magnetic
moments in the case of bond dilution, and that the antiferromagnetic
long-range-ordered phase does not appear until the magnitudes of the two
interactions become comparable.Comment: 7 pages, 13 figure
Classical Correlation-Length Exponent in Non-Universal Quantum Phase Transition of Diluted Heisenberg Antiferromagnet
Critical behavior of the quantum phase transition of a site-diluted
Heisenberg antiferromagnet on a square lattice is investigated by means of the
quantum Monte Carlo simulation with the continuous-imaginary-time loop
algorithm. Although the staggered spin correlation function decays in a power
law with the exponent definitely depending on the spin size , the
correlation-length exponent is classical, i.e., . This implies that
the length scale characterizing the non-universal quantum phase transition is
nothing but the mean size of connected spin clusters.Comment: 4 pages, 3 figure
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