Changing trends and the impact of alcohol on the HIV/AIDS epidemic in South Africa: Review

The association between increased HIV infection and alcohol use has been extensively studied and is established. South Africa is among one of the sub-Saharan African countries with the highest prevalence and number of people living with HIV/AIDS in the world. Although recent evidence suggests that the epidemic has stabilised, infection rates remain unacceptably high. Alcohol use is on the increase, particularly in the groups most susceptible to HIV infection, namely women and young adults, and informs poor choices with respect to safer sexual practices. This paper reviews the association between alcohol and HIV. More specifically, however, it aims to explore the potential socio-politico-biological and cultural explanations as to the factors that intersect to drive these two epidemic diseases: alcoholism and HIV/AIDS in South Africa. Understanding some of the underlying factors will provide a framework to implement public health measures to curb HIV.Keywords: HIV, AIDS, South Africa, alcohol, politics of South Africa.L’association entre l’augmentation du VIH et la consommation d’alcool fait l’objet d’une étude. L’Afrique du Sud reste l’un des pays Sub-Saharien les plus touché par un taux de prévalence élevé et par le nombre de personnes vivant avec le VIH/SIDA dans le monde. Bien que les dernières objectives fussent de stabiliser l’épidémie, néanmoins le taux d’infection reste inacceptable. L’utilisation de l’alcool, particulièrement chez les femmes et les jeunes, est susceptible d’augmenter l’infection du VIH, et le peu d’information qu’ils ont sur le respect des pratiques sexuels sûr. L’article examine le lien entre l’association de l’alcool et le VIH, plus spécifiquement, cependant elle vise à explorer des explications potentielles socio-politico-culturelles et biologiques sur les facteurs de ces maladies épidémiques alcoolisme et le VIH/SIDA en Afrique du Sud. Il faut comprendre que les facteurs sous-jacents fourniront un cadre pour mettre en oeuvre des mesures de santé publique pour lutter contre le VIH

Noise-induced macroscopic bifurcations in globally-coupled chaotic units

Large populations of globally-coupled identical maps subjected to independent additive noise are shown to undergo qualitative changes as the features of the stochastic process are varied. We show that for strong coupling, the collective dynamics can be described in terms of a few effective macroscopic degrees of freedom, whose deterministic equations of motion are systematically derived through an order parameter expansion.Comment: Phys. Rev. Lett., accepte

Evolving social behavior through selection of single-cell adhesion in Dictyostelium discoideum

The social amoeba Dictyostelium discoideum commonly forms chimeric fruiting bodies. Genetic variants that produce a higher proportion of spores are predicted to undercut multicellular organization unless cooperators assort positively. Cell adhesion is considered a primary factor driving such assortment, but evolution of adhesion has not been experimentally connected to changes in social performance. We modified by experimental evolution the efficiency of individual cells in attaching to a surface. Surprisingly, evolution appears to have produced social cooperators irrespective of whether stronger or weaker adhesion was selected. Quantification of reproductive success, cell-cell adhesion, and developmental patterns, however, revealed two distinct social behaviors, as captured when the classical metric for social success is generalized by considering clonal spore production. Our work shows that cell mechanical interactions can constrain the evolution of development and sociality in chimeras and that elucidation of proximate mechanisms is necessary to understand the ultimate emergence of multicellular organization

Viscoelastic material behaviour of PBT-GF30 under thermo-mechanical cyclic loading

Abstract This paper deals with the simulation of the behaviour of a short glass fibre reinforced polybutylene terephthalate (PBT-GF30) under thermo-mechanical cyclic loading. Thermo-mechanical fatigue (TMF) tests, consisting of thermal cycling with a superimposed constant strain, have been carried out in the temperature ranges of -40 °C to 120 °C and -40 °C to 40 °C, applying different mean strain values. The main goal of the work is to model the stress trend during TMF cycles and assess the performance of a linear viscoelastic material model. A linear viscoelastic model has been implemented in ABAQUS 6.9-1 by means of Prony series, using the UTRS subroutine to model the time-temperature shift. The stress-time trend during TMF tests is discussed, comparing the simulated versus the experimental stress results. In particular, the maximum and minimum values within each cycle are considered, in order to evaluate the performance of the material model. Linear viscoelastic simulations show good agreement between experimental tests and FE analysis, both for plain and notched specimen

Produção de matéria seca e teores de nitrogênio em milho para silagem adubado com uréia misturada a zeólita.

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Acetaldehyde adducts in alcoholic liver disease

Chronic alcohol abuse causes liver disease that progresses from simple steatosis through stages of steatohepatitis, fibrosis, cirrhosis, and eventually hepatic failure. In addition, chronic alcoholic liver disease (ALD), with or without cirrhosis, increases risk for hepatocellular carcinoma (HCC). Acetaldehyde, a major toxic metabolite, is one of the principal culprits mediating fibrogenic and mutagenic effects of alcohol in the liver. Mechanistically, acetaldehyde promotes adduct formation, leading to functional impairments of key proteins, including enzymes, as well as DNA damage, which promotes mutagenesis. Why certain individuals who heavily abuse alcohol, develop HCC (7.2–15%) versus cirrhosis (15–20%) is not known, but genetics and co-existing viral infection are considered pathogenic factors. Moreover, adverse effects of acetaldehyde on the cardiovascular and hematologic systems leading to ischemia, heart failure, and coagulation disorders, can exacerbate hepatic injury and increase risk for liver failure. Herein, we review the role of acetaldehyde adducts in the pathogenesis of chronic ALD and HCC

Produção de matéria seca, extração e utilização de nitrogênio em aveia adubada com uréia em mistura com zeólita.

A perda de nitrogênio (N) por volatilização de amônia é um dos principais fatores responsáveis pela baixa eficiência da uréia aplicada sobre a superfície do solo. A redução das perdas por volatilização pode ser obtida com o de zeólitas como aditivo à uréia. Zeólitas são minerais alumino-silicatos cristalinos hidratados de metais alcalinos ou alcalinos-terrosos, estruturados em redes cristalinas tridimensionais rígidas, formadas por tetraedros de AlO4 e SiO4 e de ocorrência natural. O objetivo deste trabalho foi avaliar o efeito da mistura de zeólita à uréia na adubação nitrogenada da aveia sobre a produção de matéria seca, extração e utilização de nitrogênio. O delineamento experimental adotado foi em blocos ao acaso em esquema fatorial 2X2X2X4, com 3 repetições. Os tratamentos foram 2 tipos de zeólita estilbita (natural = 470 g kg-1 e concentrada = 650 g kg-1), 2 granulometrias (<1mm e <0,3mm), 2 níveis de nitrogênio (100 e 200 mg kg-1 ); e 4 relações de zeólita (testemunha, 25, 50 e 100% m/m da dose de N). Os tratamentos foram aplicados na adubação da aveia conduzida em vasos e em casa-de-vegetação. Os melhores resultados de produção de matéria seca foram obtidos a dose de 200 mg kg-1 de N em mistura com 59,8% de zeólita concentrada (650 g kg-1 de estilbita). A melhor eficiência de uso foi alcançada com o uso das doses mais baixas de nitrogênio da uréia