On the well posedness of the Baumgarte-Shapiro-Shibata-Nakamura formulation of Einstein's field equations

We give a well posed initial value formulation of the Baumgarte-Shapiro-Shibata-Nakamura form of Einstein's equations with gauge conditions given by a Bona-Masso like slicing condition for the lapse and a frozen shift. This is achieved by introducing extra variables and recasting the evolution equations into a first order symmetric hyperbolic system. We also consider the presence of artificial boundaries and derive a set of boundary conditions that guarantee that the resulting initial-boundary value problem is well posed, though not necessarily compatible with the constraints. In the case of dynamical gauge conditions for the lapse and shift we obtain a class of evolution equations which are strongly hyperbolic and so yield well posed initial value formulations

Red meat, micronutrients and oral squamous cell carcinoma of Argentine adult patients.

Introduction: the identification of risk group of oral cancer allows reducing the typical morbidity and mortality rates of this pathology. Objetive: it was analyzed the role of red meat, macronutrients and micronutrients on Oral Squamous Cell carcinoma (OSCC) in a case–control study carried out in Cordoba, Argentina. Methods: case-control study 3:1, both genders, aged 24-80 years. Dietary information was collected using a quali-quantitative food frequency questionnaire. The logistic regression was applied for assessing the association among case/control status and daily red meat/macronutrient/micronutrients/energy intake. Results: micronutrients and minerals in the diet that showed high significant median values of common consumption in cases relative to controls were iron, phosphorus, vitamins B1, B5, B6, E and K and selenium. The association measurement estimated by logistic regression was showed that a significant association between red meat, fat, daily energy, phosphorous, vitamin B5, vitamin E, and selenium intake and OSCC presence. Conclusions: a high intake of fats, phosphorus, vitamin B5, vitamin E, and selenium intake and red meat appears to be related to the presence OSCC in Cordoba, Argentina. In relation to red meat consumption and risk of OSCC, the future research should center of attention on reducing the complexity of diet and disease relationships and reducing variability in intake data by standardizing of criteria in order to implement simple strategies in public health for recognizing risk groups of OSCC.publishedVersio

Resíduo do processo de fabricação de papel reciclado - potencial de uso como insumo agrícola e/ou florestal.

Resumo

On the inviscid and non-resistive limit for the equations of incompressible magnetohydrodynamics

We prove the convergence of the solutions for the incompressible homogeneous magnetohydrodynamics (MHD) system to the solutions to ideal MHD one in the inviscid and non-resistive limit, detailing the explicit convergence rates. For this study we consider a fluid occupying the whole space R3 and we assume that the viscosity effects in this fluid can be described by two different operators: the usual Laplacian operator affected by the inverse of the Reynolds number or by a viscosity operator introduced by S. I. Braginskii in 1965

Well-Posed Initial-Boundary Evolution in General Relativity

Maximally dissipative boundary conditions are applied to the initial-boundary value problem for Einstein's equations in harmonic coordinates to show that it is well-posed for homogeneous boundary data and for boundary data that is small in a linearized sense. The method is implemented as a nonlinear evolution code which satisfies convergence tests in the nonlinear regime and is robustly stable in the weak field regime. A linearized version has been stably matched to a characteristic code to compute the gravitational waveform radiated to infinity.Comment: 5 pages, 6 figures; added another convergence plot to Fig. 2 + minor change