Bone structure, strength and microhardness resulting after hindlimb unloading in rats

Introduction: Bone strength is influenced by a number of different determinants, such as mass, size, geometry and also by the intrinsic material properties of the tissue. Aims: The structure and mechanical properties of the femur were analyzed in aged (14 mo-old) animals submitted to hindlimb unloading (HU) for 21 days. Methods: Twenty Wistar rats were randomly divided into Control and HU groups and the femur was submitted to dual X ray absorptiometry (DXA), DIGORA radiographic density, mechanical compression testing and Knoop microhardness analyse in cortical and cancellous bone. Results: Femurs from HU group presented significantly lower failure load, decreased bone mineral density (BMD)/bone mineral content (BMC) in whole bone; proximal/distal epiphysis and middiaphyseal cortical bone measured by DXA were similar in the two groups; radiographic density from areas in proximal epiphysis was significantly lower in HU group, and microhardness measured at periosteal and endosteal levels were also signifcantly diminished in HU compared with Control group. Conclusion: Disuse induced damage in the trabecular femoral bone architecture with decisive effect on the head and trochanteric fossa, which became weaker. Bone diaphyseal cortical hardness also suffered effect of unloading, probably related to osteocyte/osteoblast activity.

Cardiac remodeling induced by smoking: Concepts, relevance, and potential mechanisms

Cardiac or ventricular remodeling is characterized by molecular, cellular, and interstitial alterations that lead to changes in heart size, mass, geometry and function in response to a given insult. Currently, tobacco smoke exposure is recognized as one of these insults. Indeed, tobacco smoke exposure induces the enlargement of the left-sided cardiac chambers, myocardial hypertrophy, and ventricular dysfunction. Potential mechanisms for these alterations include hemodynamic and neurohormonal changes, oxidative stress, inflammation, nitric oxide bioavailability, matrix metalloproteinases and mitogen-activated protein kinase activation. This review will focus on the concepts, relevance, and potential mechanisms of cardiac remodeling induced by tobacco smoke. © 2012 Bentham Science Publishers.

Application of a bounded upwinding scheme to complex fluid dynamics problems

This paper is concerned with an overview of upwinding schemes, and further nonlinear applications of a recently introduced high resolution upwind differencing scheme, namely the ADBQUICKEST [V.G. Ferreira, F.A. Kurokawa, R.A.B. Queiroz, M.K. Kaibara, C.M. Oishi, J.A.Cuminato, A.F. Castelo, M.F. Tomé, S. McKee, assessment of a high-order finite difference upwind scheme for the simulation of convection-diffusion problems, International Journal for Numerical Methods in Fluids 60 (2009) 1-26]. The ADBQUICKEST scheme is a new TVD version of the QUICKEST [B.P. Leonard, A stable and accurate convective modeling procedure based on quadratic upstream interpolation, Computer Methods in Applied Mechanics and Engineering 19 (1979) 59-98] for solving nonlinear balance laws. The scheme is based on the concept of NV and TVD formalisms and satisfies a convective boundedness criterion. The accuracy of the scheme is compared with other popularly used convective upwinding schemes (see, for example, Roe (1985) [19], Van Leer (1974) [18] and Arora & Roe (1997) [17]) for solving nonlinear conservation laws (for example, Buckley-Leverett, shallow water and Euler equations). The ADBQUICKEST scheme is then used to solve six types of fluid flow problems of increasing complexity: namely, 2D aerosol filtration by fibrous filters; axisymmetric flow in a tubular membrane; 2D two-phase flow in a fluidized bed; 2D compressible Orszag-Tang MHD vortex; axisymmetric jet onto a flat surface at low Reynolds number and full 3D incompressible flows involving moving free surfaces. The numerical simulations indicate that this convective upwinding scheme is a good generic alternative for solving complex fluid dynamics problems. © 2012.

Olhares que pensam e sentem: arte e mediação cultural na aula de geometria

Pós-graduação em Artes - IA

Modelagem e simulação das juntas de um manipulador robótico cilíndrico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Neostructuralism and heterodox thinking in Latin America and the Caribbean in the early twenty-first century

The thinking that has unilaterally dominated economic science for over five decades has recently come under intensive scrutiny and its validity and conceptual and empirical coherence are the subject of controversy. Thus the limitations of the prevailing paradigm for addressing the failures of free market economies have been laid bare. For Latin America and the Caribbean, these failures are structural in nature, as indeed structuralism proposed in its time. Neostructuralism delves more deeply into the issues addressed in structuralism, aiming to improve positioning in the international economy, boost productive employment creation, reduce structural heterogeneity and improve income distribution, while maintaining financial balances capable of sustaining changes in the sphere of production by means of social and State support. Far from being an insular system of thinking, neostructuralism is an open system that lends itself to dialogue with other philosophies that recognize the limitations of the dominant paradigm and object to its methodological monism. This book offers a fresh look at neostructuralism and heterodox thinking at the start of the twenty-first century. In a context shaped by the impacts of the worst economic and financial crisis since the Great Depression and by paradigmatic changes at the global level, it aims to carve out arenas for discussion between alternative lines of thinking in order to lay the foundations for a socioeconomically inclusive and environmentally sustainable model of development for the region.

Sentidos de percepção e educação matemática: geometria dinâmica e ensino de funções com auxílio de representações dinâmicas

Pós-graduação em Educação Matemática - IGCE

Momento bossa nova: arte, cultura e representação sob os olhares da revista O Cruzeiro

Pós-graduação em História - FCLAS

Modelamento e correção de descentralização das imagens de tempo de trânsito

As imagens da parede do poço obtidas através da ferramenta UBI (Ultrasonic Borehole Imager) são amplamente utilizadas por geólogos e engenheiros de petróleo para identificar eventos geológicos nas paredes de poços abertos e na inspeção dos tubos de revestimento, uma vez que este perfil praticamente fornece uma fotografia da parede do poço. As ferramentas de imageamento acústico produzem imagens do tempo de trânsito e da amplitude do pulso acústico gerado pela ferramenta e refletido na parede do poço. Entretanto, estas imagens podem ter uma interpretação não realista, uma vez que elas podem ter seu aspecto alterado em razão do movimento da ferramenta no interior do poço. Este trabalho apresenta o modelamento das imagens de tempo de trânsito a partir da aplicação do critério de Coulomb para a ruptura da parede do poço submetida a um estado plano de tensões, a qual fornecerá a seção do poço, que é a forma geométrica que será traçada pela ferramenta de imageamento acústico do poço. O deslocamento ascensional da ferramenta e as imperfeições da parede do poço, normalmente, são os responsáveis pelo deslocamento da posição do transdutor em relação ao eixo do poço. Este efeito pode ter grande responsabilidade nas imperfeições das imagens de tempo de trânsito. Assim, a correção dessas imagens, chamada de correção da descentralização, busca o reposicionamento do transdutor para a posição do eixo do poço. Apresenta-se, também, um método de correção do efeito da descentralização da ferramenta baseado neste modelamento. O método é proposto com base na geometria analítica plana e no método do raio para a definição do tempo de trânsito do pulso acústico, com o objetivo de reconstruir as imagens de tempo de trânsito obtidas com a ferramenta descentralizada, ou seja, corrigir estas imagens tornando-as como se fossem obtidas com a ferramenta centralizada em relação ao eixo do poço.

First-Principles Study of Pressure-Induced Phase Transitions and Electronic Properties of Ag2MoO4

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Metodologia computacional baseada em DFT, para compreensão de processos eletródicos em fases intermetálicas ordenadas

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Dissolved uranium, radium and radon evolution in the Continental Intercalaire aquifer, Algeria and Tunisia

Natural, dissolved U-238-series radionuclides (U, Ra-226, Rn-222) and activity ratios (A.R.s: U-234/U-238; Ra-228/Ra-226) in Continental Intercalaire (Cl) groundwaters and limited samples from the overlying Complexe Terminal (CT) aquifers of Algeria and Tunisia are discussed alongside core measurements for U/Th (and K) in the contexts of radiological water quality, geochemical controls in the aquifer, and water residence times. A redox barrier is characterised downgradient in the Algerian Cl for which a trend of increasing U-234/U-238 A.R.s with decreasing U-contents due to recoil-dominated U-234 solution under reducing conditions allows residence time modelling similar to 500 ka for the highest enhanced A.R. = 3.17. Geochemical modelling therefore identifies waters towards the centre of the Grand Erg Oriental basin as palaeowaters in line with reported C-14 and Cl-36 ages. A similar U-234/U-238 trend is evidenced in a few of the Tunisian CI waters. The paleoage status of these waters is affirmed by both noble gas recharge temperatures and simple modelling of dissolved, radiogenic He-4-contents both for sampled Algerian and Tunisian CI and CT waters. For the regions studied these waters therefore should be regarded as "fossil" waters and treated effectively as a non-renewable resource. (C) 2014 The Authors. Published by Elsevier Ltd.

On the stability of the RuCl2(triphenylphosphine)(2)(amine) complexes: Ligand substituent effects of cyclic and acyclic amines

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Combined active and semi-supervised learning using particle walking temporal dynamicscombined active and semi-supervised learning using particle walking temporal dynamics

Both Semi-Supervised Leaning and Active Learning are techniques used when unlabeled data is abundant, but the process of labeling them is expensive and/or time consuming. In this paper, those two machine learning techniques are combined into a single nature-inspired method. It features particles walking on a network built from the data set, using a unique random-greedy rule to select neighbors to visit. The particles, which have both competitive and cooperative behavior, are created on the network as the result of label queries. They may be created as the algorithm executes and only nodes affected by the new particles have to be updated. Therefore, it saves execution time compared to traditional active learning frameworks, in which the learning algorithm has to be executed several times. The data items to be queried are select based on information extracted from the nodes and particles temporal dynamics. Two different rules for queries are explored in this paper, one of them is based on querying by uncertainty approaches and the other is based on data and labeled nodes distribution. Each of them may perform better than the other according to some data sets peculiarities. Experimental results on some real-world data sets are provided, and the proposed method outperforms the semi-supervised learning method, from which it is derived, in all of them.