Environmental Epidemiology of Intestinal Schistosomiasis in Uganda: Population Dynamics of Biomphalaria (Gastropoda: Planorbidae) in Lake Albert and Lake Victoria with Observations on Natural Infections with Digenetic Trematodes

This study documented the population dynamics of Biomphalaria and associated natural infections with digenetic trematodes, along the shores of Lake Albert and Lake Victoria, recording local physicochemical factors. Over a two-and-a-half-year study period with monthly sampling, physicochemical factors were measured at 12 survey sites and all freshwater snails were collected. Retained Biomphalaria were subsequently monitored in laboratory aquaria for shedding trematode cercariae, which were classified as either human infective (Schistosoma mansoni) or nonhuman infective. The population dynamics of Biomphalaria differed by location and by lake and had positive relationship with pH (P < 0.001) in both lakes and negative relationship with conductivity (P = 0.04) in Lake Albert. Of the Biomphalaria collected in Lake Albert (N = 6,183), 8.9% were infected with digenetic trematodes of which 15.8% were shedding S. mansoni cercariae and 84.2% with nonhuman infective cercariae. In Lake Victoria, 2.1% of collected Biomphalaria (N = 13,172) were infected with digenetic trematodes with 13.9% shedding S. mansoni cercariae, 85.7% shedding nonhuman infective cercariae, and 0.4% of infected snails shedding both types of cercariae. Upon morphological identification, species of Biomphalaria infected included B. sudanica, B. pfeifferi, and B. stanleyi in Lake Albert and B. sudanica, B. pfeifferi, and B. choanomphala in Lake Victoria. The study found the physicochemical factors that influenced Biomphalaria population and infections. The number and extent of snails shedding S. mansoni cercariae illustrate the high risk of transmission within these lake settings. For better control of this disease, greater effort should be placed on reducing environmental contamination by improvement of local water sanitation and hygiene

Adolescent and adult pregnant women: different risk circumstances?

Resumo: Este estudo teve por objectivo caracterizar as circunstâncias em que decorre a gravidez na adolescência e na idade adulta e analisar as principais diferenças, ao nível das condições demográficas, sociais, anteriores de existência e actuais da gravidez. Uma amostra de 130 utentes da Maternidade Júlio Dinis (Porto) (66 grávidas adolescentes e 64 grávidas adultas) foi entrevistada através da Contextual Assessment of the Maternity Experience (CAME, Bernazzani, Marks, Siddle, Asten, Bifulco, et al, 2004), no último trimestre de gravidez. Os resultados mostram que à gravidez na adolescência se associa um elevado número de condições menos favoráveis, que podem comprometer a gestação e os cuidados ao bebé, como por exemplo: desemprego, monoparentalidade, consumo de tabaco, condições anteriores de existência adversas e gravidez não desejada. No entanto, outras circunstâncias adversas estão associadas à gravidez na idade adulta, como seja: história de problemas de fertilidade e de problemas psicológicos com tratamento ou internamento e ausência por morte de pelo menos um dos pais. Conclui-se que um número considerável de grávidas adolescentes vive em condições desfavoráveis, pelo que, não obstante a sua variabilidade, o grupo enquanto um todo pode ser considerado de risco, quando comparado ao grupo de grávidas adultas. Conclui-se ainda que grávidas adolescentes e adultas vivem a gravidez em condições específicas; observam-se diferentes circunstâncias de risco junto de cada um destes dois grupo, que devem ser atendidas na adequação da ajuda prestada pelos técnicos de saúde às reais necessidades das mães.Financiado pela Fundação para a Ciência e Tecnologia (POCTI/S/SAU/14109/98) e Serviço de Saúde e Desenvolvimento Humano da Fundação Calouste Gulbenkian (Proc. 48914/02-04

Sistematização de dados bibliográficos relacionados aos impactos ambientais da produção agrícola sobre as águas fluviais no corredor de Nacala, Moçambique.

Resumo: As atividades do bolsista foram desenvolvidas no escopo do ProSAVANA-TEC (Projeto de Melhoria da Capacidade de Pesquisa e de Transferência de Tecnologia para o Desenvolvimento da Agricultura no Corredor de Nacala em Moçambique), organizando levantamentos bibliográficos de informações disponíveis na internet sobre a qualidade da água superficial nas bacias hidrográficas localizadas na região do Corredor de Nacala e em Moçambique como um todo. A organização do material bibliográfico foi realizada por meio dos programas computacionais "ZOTERO", "MENDELEY.COM" e "MENDELEY- DESKTOP". Por fim, obteve-se uma coletânea de material bibliográfico, organizado digitalmente, para otimizar as consultas bibliográficas dos membros da equipe do ProSavana, assim como de outros interessados nos temas desta coletânea, assim facilitada pelo uso da ferramenta computacional selecionada. Abstract: The activities of the grantee have been developed within the scope of ProSavana-TEC (Project Capacity Enhancement of Research and Technology Transfer for the Development of Agriculture in the Nacala Corridor in Mozambique), organizing bibliographic information available on the internet about the surface water quality in the river basins located in the region of the Nacala Corridor as well as Mozambique as a whole. The organization of the bibliographic material was performed by the use of the softwares"Zotero", "MENDELEY.COM" and "Mendeley-DESKTOP". Finally, we obtained a collection of bibliographic material, that was digitally organized, to optimize the bibliographic queries of theProSavana team members as well as queries of other people interested in topics of this collection , which access will be facilitated by the use of the selected computational tools

Statistical models of mixtures with a biaxial nematic phase

We consider a simple Maier-Saupe statistical model with the inclusion of disorder degrees of freedom to mimic the phase diagram of a mixture of rod-like and disc-like molecules. A quenched distribution of shapes leads to the existence of a stable biaxial nematic phase, in qualitative agreement with experimental findings for some ternary lyotropic liquid mixtures. An annealed distribution, however, which is more adequate to liquid mixtures, precludes the stability of this biaxial phase. We then use a two-temperature formalism, and assume a separation of relaxation times, to show that a partial degree of annealing is already sufficient to stabilize a biaxial nematic structure.Comment: 11 pages, 2 figure

Nonequilibrium modeling of an ammonia-water rectifyng column via fundamental thermodynamic and transport relations

A nonequilibrium heat and mass transfer model is presented for the steady-state operation of a rectifying column, employed in ammonia-water absorption refrigeration systems to dehumidify the ammonia vapor leaving the generator. The thermodynamic state relations of the mixture are derived from two equations representing the Gibbs free energy in terms of temperature, pressure and concentration for the liquid and the vapor phases. Two of the transport properties, surface tension and liquid diffusivity required original relations, as presented here in. The resulting nonlinear system of equations is solved by efficient use of the Newton-Raphson code that minimizes the order of the Jacobian matrix without losing any model information or the quadratic order of convergence of the numerical method. Accuracy tests are performed by grid refinement and by comparison with results in the literature. A sensitivity study is presented showing the influence of some alternative methods for estimation of the transport properties on the temperature and concentration profiles.54055

Transformations of Heun's equation and its integral relations

We find transformations of variables which preserve the form of the equation for the kernels of integral relations among solutions of the Heun equation. These transformations lead to new kernels for the Heun equation, given by single hypergeometric functions (Lambe-Ward-type kernels) and by products of two hypergeometric functions (Erd\'elyi-type). Such kernels, by a limiting process, also afford new kernels for the confluent Heun equation.Comment: This version was published in J. Phys. A: Math. Theor. 44 (2011) 07520