New Constraints on the Variable Equation of State Parameter from X-Ray Gas Mass Fractions and SNe Ia

Recent measurements are suggesting that we live in a flat Universe and that its present accelerating stage is driven by a dark energy component whose equation of state may evolve in time. Assuming two different parameterizations for the function $\omega(z)$, we constrain their free parameters from a joint analysis involving measurements from X-Ray luminosity of galaxy clusters and SNe type Ia data.Comment: paper, 6 pages, 1 figure Accepted by Int. Journal of Modern Physics D (IJPMD

Boas práticas e sistema APPCC na fase de pós-colheita de milho.

bitstream/CNPMS-2010/22381/1/Circ-122.pd

Third and fourth degree collisional moments for inelastic Maxwell models

The third and fourth degree collisional moments for $d$-dimensional inelastic Maxwell models are exactly evaluated in terms of the velocity moments, with explicit expressions for the associated eigenvalues and cross coefficients as functions of the coefficient of normal restitution. The results are applied to the analysis of the time evolution of the moments (scaled with the thermal speed) in the free cooling problem. It is observed that the characteristic relaxation time toward the homogeneous cooling state decreases as the anisotropy of the corresponding moment increases. In particular, in contrast to what happens in the one-dimensional case, all the anisotropic moments of degree equal to or less than four vanish in the homogeneous cooling state for $d\geq 2$.Comment: 15 pages, 3 figures; v2: addition of two new reference

Lixiviação de atrazina em solo em área de recarga do Aquífero Guarani.

No Aqüífero Guarani, o maior e mais importante lençol de água subterrânea de toda a região centro-sul do país, encontra-se a microbacia do Córrego do Espraiado, um dos seus pontos de recarga. Nesta área, existe predomínio de culturas, nas quais são utilizados herbicidas da família das triazinas e a presença de solo arenoso, que tornam a área vulnerável à lixiviação. Entre os produtos aplicados encontra-se a atrazina (2-chloro-4-(ethylamino)-6-(isopropylamino)-S-triazine). Devido as suas características físico-químicas, esse herbicida tem alto potencial de risco de movimentar-se para água subterrânea. Para avaliar a lixiviação da atrazina foram feitas amostragens de solo para análise física e de água superficial e subterrânea, durante os anos de 2000 a 2002, para análise de resíduo através de cromatografia líquida HPLC (High Performance Liquid Chromatography), e confirmadas com GC-MS (Gas chromatography-mass spectrometry). Apenas quatro amostras de água superficial apresentaram resíduos de atrazina. Destas, duas com 0,04; e as outras com 0,05 e 0,09 ug/L. Nas amostras de água subterrânea os resultados indicaram uma amostra contendo 0,03 ug/L de atrazina. Entretanto, nenhuma delas foi confirmada pelo GC-MS, não indicando resíduos. A presente avaliação contou também com o uso do simulador de sistemas CMLS-94 (Chemical Movement in Layered Soils). O simulador também mostrou que a atrazina não atinge profundidades comprometedoras para a qualidade do aquífero

Noncommutative fluid dynamics in the Snyder space-time

In this paper, we construct for the first time the non-commutative fluid with the deformed Poincare invariance. To this end, the realization formalism of the noncommutative spaces is employed and the results are particularized to the Snyder space. The non-commutative fluid generalizes the fluid model in the action functional formulation to the noncommutative space. The fluid equations of motion and the conserved energy-momentum tensor are obtained.Comment: 12 pages. Version published by Phys. Rev.

Solution of classical stochastic one dimensional many-body systems

We propose a simple method that allows, in one dimension, to solve exactly a wide class of classical stochastic many-body systems far from equilibrium. For the sake of illustration and without loss of generality, we focus on a model that describes the asymmetric diffusion of hard core particles in the presence of an external source and instantaneous annihilation. Starting from a Master equation formulation of the problem we show that the density and multi-point correlation functions obey a closed set of integro-differential equations which in turn can be solved numerically and/or analyticallyComment: 2 figure

Nonlinear viscosity and velocity distribution function in a simple longitudinal flow

A compressible flow characterized by a velocity field $u_x(x,t)=ax/(1+at)$ is analyzed by means of the Boltzmann equation and the Bhatnagar-Gross-Krook kinetic model. The sign of the control parameter (the longitudinal deformation rate $a$) distinguishes between an expansion ($a>0$) and a condensation ($a<0$) phenomenon. The temperature is a decreasing function of time in the former case, while it is an increasing function in the latter. The non-Newtonian behavior of the gas is described by a dimensionless nonlinear viscosity $\eta^*(a^*)$, that depends on the dimensionless longitudinal rate $a^*$. The Chapman-Enskog expansion of $\eta^*$ in powers of $a^*$ is seen to be only asymptotic (except in the case of Maxwell molecules). The velocity distribution function is also studied. At any value of $a^*$, it exhibits an algebraic high-velocity tail that is responsible for the divergence of velocity moments. For sufficiently negative $a^*$, moments of degree four and higher may diverge, while for positive $a^*$ the divergence occurs in moments of degree equal to or larger than eight.Comment: 18 pages (Revtex), including 5 figures (eps). Analysis of the heat flux plus other minor changes added. Revised version accepted for publication in PR

Non-invasive detection of adulterated olive oil in full bottles using time-domain NMR relaxometry.

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