A practical method of estimating energy expenditure during tennis play

This study aimed to develop a practical method of estimating energy expenditure (EE) during tennis. Twenty-four elite female tennis players first completed a tennis-specific graded test in which five different intensity levels were applied randomly. Each intensity level was intended to simulate a game of singles tennis and comprised six 14 s periods of activity alternated with 20 s of active rest. Oxygen consumption (VO2) and heart rate (HR) were measured continuously and each player's rate of perceived exertion (RPE) was recorded at the end of each intensity level. Rate of energy expenditure (EEVO2) during the test was calculated using the sum of VO2 during play and the 'O-2 debt' during recovery, divided by the duration of the activity. There were significant individual linear relationships between EEVO2 and RPE, EEVO2 and HR, (rgreater than or equal to0.89 rgreater than or equal to0.93; p

Surface diffusion of strongly adsorbing vapors in activated carbon by a differential permeation method

Conventional methods to determine surface diffusion of adsorbed molecules are proven to be inadequate for strongly adsorbing vapors on activated carbon. Knudsen diffusion permeability (B-k) for strongly adsorbing vapors cannot be directly estimated from that of inert gases such as helium. In this paper three models are considered to elucidate the mechanism of surface diffusion in activated carbon. The transport mechanism in all three models is a combination of Knudsen diffusion, viscous flow and surface diffusion. The collision reflection factor f (which is the fraction of molecules undergoing collision to the solid surface over reflection from the surface) of the Knudsen diffusivity is assumed to be a function of loading. It was found to be 1.79 in the limit of zero loading, and decreases as loading increases. The surface diffusion permeability increases sharply at very low pressures and then starts to decrease after it has reached a maximum (B(mum)s) at a threshold pressure. The initial rapid increase in the total permeability is mainly attributed to surface diffusion. Interestingly the B(mum)s for all adsorbates appear at the same volumetric adsorbed phase concentration, suggesting that the volume of adsorbed molecules may play an important role in the surface diffusion mechanism in activated carbon. (C) 2003 Elsevier Ltd. All rights reserved.

A new wavelet-based adaptive method for solving population balance equations

A new wavelet-based adaptive framework for solving population balance equations (PBEs) is proposed in this work. The technique is general, powerful and efficient without the need for prior assumptions about the characteristics of the processes. Because there are steeply varying number densities across a size range, a new strategy is developed to select the optimal order of resolution and the collocation points based on an interpolating wavelet transform (IWT). The proposed technique has been tested for size-independent agglomeration, agglomeration with a linear summation kernel and agglomeration with a nonlinear kernel. In all cases, the predicted and analytical particle size distributions (PSDs) are in excellent agreement. Further work on the solution of the general population balance equations with nucleation, growth and agglomeration and the solution of steady-state population balance equations will be presented in this framework. (C) 2002 Elsevier Science B.V. All rights reserved.

Method for determining the shear stress in cylindrical systems

We develop a method for determining the elements of the pressure tensor at a radius r in a cylindrically symmetric system, analogous to the so-called method of planes used in planar systems [B. D. Todd, Denis J. Evans, and Peter J. Daivis, Phys. Rev. E 52, 1627 (1995)]. We demonstrate its application in determining the radial shear stress dependence during molecular dynamics simulations of the forced flow of methane in cylindrical silica mesopores. Such expressions are useful for the examination of constitutive relations in the context of transport in confined systems.

Mapping the royal road and other hierarchical functions

In this paper we present a technique for visualising hierarchical and symmetric, multimodal fitness functions that have been investigated in the evolutionary computation literature. The focus of this technique is on landscapes in moderate-dimensional, binary spaces (i.e., fitness functions defined over {0, 1}(n), for n less than or equal to 16). The visualisation approach involves an unfolding of the hyperspace into a two-dimensional graph, whose layout represents the topology of the space using a recursive relationship, and whose shading defines the shape of the cost surface defined on the space. Using this technique we present case-study explorations of three fitness functions: royal road, hierarchical-if-and-only-if (H-IFF), and hierarchically decomposable functions (HDF). The visualisation approach provides an insight into the properties of these functions, particularly with respect to the size and shape of the basins of attraction around each of the local optima.

Adapted Gaussian basis sets for atoms from Li through Xe generated with the generator coordinate Hartree-Fock method

Utiliza-se o método coordenada geradora Hartree-Fock para gerar bases Gaussianas adaptadas para os átomos de Li (Z=3) até Xe (Z=54). Neste método, integram-se as equações de Griffin-Hill-Wheeler-Hartree-Fock através da técnica de discretização integral. Comparam-se as funções de ondas geradas neste trabalho com as funções de ondas Roothaan-Hartree-Fock de Clementi e Roetti (1974) e com outros conjuntos de bases relatados na literatura. Para os átomos estudados aqui, os erros em nossas energias totais relativos aos limites numéricos Hartree-Fock são sempre menores que 7,426 milihartree.

Lucidez-Embriaguez, movimento e arrebatamento: homens,(Semi)deuses que perambulam e a educação menor num bairro de uma rede municipal

A tese afirma a vida por meio das biopotências que se manifestam em movimentações invisíveis aos olhos acostumados a permitir o ver, o julgar e o falar. Foca o tempo presente, na comunicação em redes, traz em si a potência de reatar a multidão, com a capacidade de sondar possibilidades mostrando o que antes parecia opaco e impossível. Perambular é ligar nas redes quentes de um bairro com/no/do território ao privilegiar o movimento, o processo, sempre caminhando pelas vias e conexões abertas, aposta estética-ética-política nos paradoxos sem superação e não hierarquizados. Toma como método de pesquisa-intervenção elementos de uma cartografia de movimentos e devires, traçando um perambular rizomático em que são problematizados a constituição do problema de pesquisa, que considera a construção do conhecimento diversificada, descentralizada e horizontalizada. Problematiza as práticas discursivas de si em suas relações com a biopolítica, a governabilidade e a biopolítica das populações. O que está(rá) rolando nesse bairro, no que foi chamado de criança, adolescente, escola, compor para que as coisas apareçam, junto com outros que vivem a loucura em duplas e trios. A tese é a possibilidade da existência de uma educação menor na periferia para as populações marginalizadas, muçulmanizadas. Educação menor, da sala de aula, do bairro, do cotidiano de professores, familiares e alunos. Educação que permite revolucionários, na medida em que alguma revolução ainda faz sentido na educação nesses dias. A educação menor constitui-se, assim, num empreendimento de militância, de professores militantes. Plano das afecções em que não há unidades, apenas intensidade. A tese fala do processo, de como reproduzir, ou não, os modos de subjetividade dominante, não se trata de medidas - "menor" ou "pequeno". Nesse sentido, é preciso considerar os efeitos de produção de subjetividade e a incorporação dos fatos à própria vida. A tese analisa movimentos instituintes buscando reconhecê-los em sua natureza contestatória e transgressora e ter conhecimento de como se organiza na escola e muito além dela. Discutindo a produtividade dessa coreografia do perambular, esboçamos movimentos que denominamos: estradas que levam a nada, além muro

The influence of the dispersion method on the electrical properties of vapor-grown carbon nanofiber/epoxy composites

The influence of the dispersion of vapor-grown carbon nanofibers (VGCNF) on the electrical properties of VGCNF/ Epoxy composites has been studied. A homogenous dispersion of the VGCNF does not imply better electrical properties. In fact, it is demonstrated that the most simple of the tested dispersion methods results in higher conductivity, since the presence of well-distributed nanofiber clusters appears to be a key factor for increasing composite conductivity.

Eigenvalue computations in the context of data-sparse approximations of integral operators

In this work, we consider the numerical solution of a large eigenvalue problem resulting from a finite rank discretization of an integral operator. We are interested in computing a few eigenpairs, with an iterative method, so a matrix representation that allows for fast matrix-vector products is required. Hierarchical matrices are appropriate for this setting, and also provide cheap LU decompositions required in the spectral transformation technique. We illustrate the use of freely available software tools to address the problem, in particular SLEPc for the eigensolvers and HLib for the construction of H-matrices. The numerical tests are performed using an astrophysics application. Results show the benefits of the data-sparse representation compared to standard storage schemes, in terms of computational cost as well as memory requirements.

Multiple centroid method to evaluate the adaptability of alfalfa genotypes

This study aimed to evaluate the efficiency of multiple centroids to study the adaptability of alfalfa genotypes (Medicago sativa L.). In this method, the genotypes are compared with ideotypes defined by the bissegmented regression model, according to the researcher's interest. Thus, genotype classification is carried out as determined by the objective of the researcher and the proposed recommendation strategy. Despite the great potential of the method, it needs to be evaluated under the biological context (with real data). In this context, we used data on the evaluation of dry matter production of 92 alfalfa cultivars, with 20 cuttings, from an experiment in randomized blocks with two repetitions carried out from November 2004 to June 2006. The multiple centroid method proved efficient for classifying alfalfa genotypes. Moreover, it showed no unambiguous indications and provided that ideotypes were defined according to the researcher's interest, facilitating data interpretation.

Importância do rating na padronização de debêntures

As debêntures padronizadas possibilitam aos investidores prescindir de complexas análises contratuais e cálculos sofisticados em mercados secundários. Este artigo analisa, com base em contratos de debêntures não padronizados, se, caso as diferenças contratuais fossem controladas estatisticamente, os ratings dessas debêntures seriam suficientes para captar os custos inerentes nas taxas de juros de suas emissões. Para tanto, analisamos uma amostra de 24 emissões de debêntures no período de 1999-2001, e verificamos se houve alguma diferença estatisticamente significativa (distribuição binomial) nas cláusulas contratuais entre as emissões com elevado rating e baixo rating. Concluímos que, para ratings elevados, a padronização afeta as taxas de juros como reflexo de seu rating. Contudo, para ratings baixos, a padronização não capta diferenças contratuais específicas, tais como repactuação programada e garantia.

A high-throughput screening method for general cytotoxicity part I Chemical toxicity

Foi desenvolvido um método destinado a fazer a triagem rápida e o escalonamento da toxicidade geral exercida por xenobióticos tendo como modelo o Saccharomyces cerevisiae. Para padronizar as condições de experimentação foi estabelecida a relação entre a absorvência a 525 nm e o número de células em suspensão por mililitro de meio de cultura e calculadas uma curva padrão e respectiva equação definidora (Y=6,8219E-08X + 0,0327) Culturas de Saccharomyces cerevisiae em meio completo para leveduras (YPD - 1% de glucose 2%, de peptona 0,5% e extracto de levedura 1%) foram expostas a diferentes concentrações de nicotina e a inibição do crescimento avaliada.