Modeling the pore level fluid flow in porous media using the immersed boundary method

This chapter demonstrates the potential of the immersed boundary method for the direct numerical simulation of the flow through porous media. A 2D compact finite differences method was employed to solve the unsteady incompressible Navier-Stokes equations with fourth-order Runge-Kutta temporal discretization and fourth-order compact schemes for spatial discretization. The solutions were obtained in a Cartesian grid, with all the associated advantages. The porous media is made of equal size square cylinders in a staggered arrangement and is bounded by solid walls. The transverse and longitudinal distances between cylinders are equal to two cylinder diameters and at the inlet a fully developed velocity profile is specified. The Reynolds number based on the cylinder diameter and maximum inlet velocity ranges from 40 to 80. The different flow regimes are identified and characterised, along with the prediction of the Reynolds number at which transition from steady to unsteady flow takes place. Additionally, the average drag and lift coefficients are presented as a function of the Reynolds number

Síndrome de Brown-Séquard na esquistossomose: relato de caso

Os autores apresentam um caso de neuroesquistossomose em um paciente de 39 anos de idade, com quadro semelhante à síndrome de Brown-Séquard. As provas imunológicas realizadas no líquido cefarraqueano comprovaram o diagnóstico, sendo instituído em seguida o tratamento adequado

Uso de álcool e drogas e sua influência sobre as práticas sexuais de adolescentes de Minas Gerais, Brasil Alcohol and illicit drug use and its influence on the sexual behavior of teenagers from Minas Gerais State, Brazil

Os achados provêm de um estudo transversal de 5.981 estudantes de escolas públicas de Minas Gerais, Brasil. Avaliou-se a influência do uso de drogas sobre as práticas sexuais. Dos rapazes com relacionamento casual que referiram ter utilizado drogas ilícitas, 55,7% disseram usar preservativos de forma consistente (em todas as relações sexuais), enquanto entre os que nunca fizeram uso de tais substâncias, esse percentual foi de 65,4%. Entre os rapazes com relacionamento fixo, que utilizaram droga ilícita, o uso consistente de preservativos foi referido por 42,7%, ao passo que, para os que nunca fizeram uso dessas substâncias, esse percentual foi de 64,1%. No subgrupo dos rapazes com parceria fixa que nunca utilizaram drogas ilícitas, o uso consistente do preservativo foi menos freqüente entre os que utilizaram cigarro e/ou álcool do que entre os que não referiram este uso (60,7% vs. 71,1%). As moças apresentaram menor proporção de uso consistente do preservativo do que os rapazes, independentemente do tipo de parceria, sem influência aparente dos padrões de consumo. Os achados sugerem a necessidade de integrar a prevenção do uso de drogas à de infecções sexualmente transmissíveis/gravidez indesejada.<br>This article summarizes the findings of a survey including 5,981 students from public schools in Minas Gerais State, Brazil. The analysis assessed the influence of drug use on sexual practices. Among the boys engaged in relationships with casual partners who stated having used illicit drugs, 55.7% reported consistent condom use, as compared to 65.4% among those not reporting such habits. Among boys engaged in relationships with stable partners who reported illicit drug use, consistent condom use was reported by 42.7%, versus 64.1% among those not reporting such habits. In the subgroup of boys engaged in stable relationships who did not report illicit drug use, consistent condom use was less frequent among those that used alcohol/cigarettes, compared to those who did not drink or smoke (60.7% vs. 71.1%). Girls were less likely than boys to use condoms consistently, regardless of the nature of their relationships, without a noticeable influence of drug use. Policies to prevent drug abuse, sexually transmitted diseases, and unplanned pregnancy should be fully integrated