3,748 research outputs found
Prognostic signatures in breast cancer: correlation does not imply causation
Testing the statistical associations between microarray-based gene expression signatures and patient outcome has become a popular approach to infer biological and clinical significance of laboratory observations. Venet and colleagues recently demonstrated that the majority of randomly generated gene signatures are significantly associated with outcome of breast cancer patients, and that this association stems from the fact that a large proportion of the transcriptome is significantly correlated with proliferation, a strong predictor of outcome in breast cancer patients. These findings demonstrate that a statistical association between a gene signature and disease outcome does not necessarily imply biological significance
Importância da apicultura no Pantanal Sul-Mato-Grossense.
Panorama da Apicultura brasileira e mundial; Apicultura no Pantanal Sul-Mato-Grossense; Caracterização; Potencial econômico; Produção extrativista; Flora apícola; Instalação do apiário; Manejo do apiário.bitstream/item/81133/1/DOC56.pd
Efeito da complementação alimentar no pós-parto sobre o desempenho produtivo de cabritos Sem Raça Definida (SRD).
A presente pesquisa foi desenvolvida numa fazenda particular em Pe- trolina- PE, no período de maio a novembro de 1995, e objetivou avaliar o efeito da complementação alimentar de matrizes sem raça definida (SRD) sobre o desem- penho produtivo dos cabritos criados em caatinga não cercada. O delineamento experimental utilizado foi inteiramente casualizado com três tratamentos (T1 : pas- tagem nativa (PN); T2: PN + 25% de NDT e T3 PN + 50% de NDT) e 16 repetições cada. A complementação alimentar foi à base de feno de leucena (Leucaena leu- cocephala (Lam.) de Wit) e raspa de mandioca (Manihot esculenta Crantz.) forne- cida a partir do primeiro dia pós-parto. Para os três tratamentos, os pesos médios observados para os cabritos, do nascimento aos 168 dias de idade, foram estatis- ticamente iguais (P>0,05). A taxa geral de mortalidade de crias aos 112 dias de idade foi de 20,41 %o Não foi possível observar efeito dos tratamentos na taxa de sobrevivência das crias, uma vez que, as causas mais comuns de desaparecimen- to dos animais são roubos e predadores
Gravitational waves effects in a Lorentz-violating scenario
This paper focuses on how the production and polarization of gravitational
waves are affected by spontaneous Lorentz symmetry breaking, which is driven by
a self-interacting vector field. Specifically, we examine the impact of a
smooth quadratic potential and a non-minimal coupling, discussing the
constraints and causality features of the linearized Einstein equation. To
analyze the polarization states of a plane wave, we consider a fixed vacuum
expectation value (VEV) of the vector field. Remarkably, we verify that a
space-like background vector field modifies the polarization plane and
introduces a longitudinal degree of freedom. In order to investigate the
Lorentz violation effect on the quadrupole formula, we use the modified Green
function. Finally, we show that the space-like component of the background
field leads to a third-order time derivative of the quadrupole moment, and the
bounds for the Lorentz-breaking coefficients are estimated as well.Comment: 19 pages and 1 figur
Quantum gases on a torus
This manuscript is aimed at studying the thermodynamic properties of quantum
gases confined to a torus. To do that, we consider \textit{noninteracting}
gases within the grand canonical ensemble formalism. In this context, fermoins
and bosons are taken into account and the calculations are properly provided in
both analytical and numerical manners. In particular, the system turns out to
be sensitive to the topological parameter under consideration: the winding
number. Furthermore, we also derive a model in order to take into account
\textit{interacting} quantum gases. To corroborate our results, we implement
such a method for two different scenarios: a ring and a torus.Comment: 22 pages, 7 figure
Thermal analysis of photon-like particles in rainbow gravity
This work is devoted to study the thermodynamic behavior of photon--like
particles within the \textit{rainbow} gravity formalism. To to do this, we
chose two particular ansatzs to accomplish our calculations. First, we consider
a dispersion relation which avoids UV divergences, getting a positive effective
cosmological constant. We provide \textit{numerical} analysis for the
thermodynamic functions of the system and bounds are estimated. Furthermore, a
phase transition is also expected for this model. Second, we consider a
dispersion relation employed in the context of \textit{Gamma Ray Bursts}.
Remarkably, for this latter case, the thermodynamic properties are calculated
in an \textit{analytical} manner and they turn out to depend on the harmonic
series , gamma , polygamma and zeta Riemann
functions .Comment: 22 pages, 7 figure
Thermodynamical properties of an ideal gas in a traversable wormhole
In this work, we analyze the thermodynamic properties of non--interacting
particles under influence of the gravitational field of a traversable wormhole.
In particular, we investigate how the thermodynamic quantities are affected by
the Ellis wormhole geometry, considering three different regions to our study:
asymptotically far, close to the throat, and at the throat. The thermodynamic
quantities turn out to depend strongly on parameter that controls the wormhole
throat radius. By varying it, there exist an expressive modification in the
thermodynamic state quantities, exhibiting both usual matter and dark
energy--like behaviors. Finally, the interactions are regarded to the energy
density and it seems to indicate that it "cures" the dark energy--like
features.Comment: 29 pages and 18 figure
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