36 resultados para Boaz


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Background Many countries are scaling up malaria interventions towards elimination. This transition changes demands on malaria diagnostics from diagnosing ill patients to detecting parasites in all carriers including asymptomatic infections and infections with low parasite densities. Detection methods suitable to local malaria epidemiology must be selected prior to transitioning a malaria control programme to elimination. A baseline malaria survey conducted in Temotu Province, Solomon Islands in late 2008, as the first step in a provincial malaria elimination programme, provided malaria epidemiology data and an opportunity to assess how well different diagnostic methods performed in this setting. Methods During the survey, 9,491 blood samples were collected and examined by microscopy for Plasmodium species and density, with a subset also examined by polymerase chain reaction (PCR) and rapid diagnostic tests (RDTs). The performances of these diagnostic methods were compared. Results A total of 256 samples were positive by microscopy, giving a point prevalence of 2.7%. The species distribution was 17.5% Plasmodium falciparum and 82.4% Plasmodium vivax. In this low transmission setting, only 17.8% of the P. falciparum and 2.9% of P. vivax infected subjects were febrile (≥38°C) at the time of the survey. A significant proportion of infections detected by microscopy, 40% and 65.6% for P. falciparum and P. vivax respectively, had parasite density below 100/μL. There was an age correlation for the proportion of parasite density below 100/μL for P. vivax infections, but not for P. falciparum infections. PCR detected substantially more infections than microscopy (point prevalence of 8.71%), indicating a large number of subjects had sub-microscopic parasitemia. The concordance between PCR and microscopy in detecting single species was greater for P. vivax (135/162) compared to P. falciparum (36/118). The malaria RDT detected the 12 microscopy and PCR positive P. falciparum, but failed to detect 12/13 microscopy and PCR positive P. vivax infections. Conclusion Asymptomatic malaria infections and infections with low and sub-microscopic parasite densities are highly prevalent in Temotu province where malaria transmission is low. This presents a challenge for elimination since the large proportion of the parasite reservoir will not be detected by standard active and passive case detection. Therefore effective mass screening and treatment campaigns will most likely need more sensitive assays such as a field deployable molecular based assay.

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A pesquisa busca compreender a atuação no Twitter das campanhas às prefeituras de São Paulo e Rio de Janeiro em 2012, de modo a entender se houve de fato uma estratégia de ação que usou as possibilidades destes sites de redes sociais para a construção de uma forma inovadora de se fazer campanha eleitoral. A partir de uma revisão de literatura que abrange desde a importância da circulação da informação política nos diferentes regimes informacionais e a midiatização das campanhas eleitorais, procurou-se discutir a emergência das campanhas online, suas principais estratégias e conceitos chave tais como a informação política não mediada, a interatividade e a mobilização bem como a discussão de casos importantes sob o ponto de vista da aplicação de técnicas de marketing à comunicação política. A parte empírica do trabalho, considerando os aspectos levantados pela perspectiva de inovação, avalia a atuação dos candidatos a prefeito de São Paulo e Rio de Janeiro nos seus perfis oficiais dos candidatos no Twitter, além das atualizações dos perfis auxiliares criados por algumas campanhas. O objetivo foi chegar a um melhor entendimento de como se deu a utilização dos sites de redes sociais por parte dos candidatos, e até que ponto tais atuações estão relacionadas à forma tradicional de se fazer campanhas eleitorais, sendo que para isso foi realizada uma análise quantitativa e de conteúdo das publicações. Os resultados apontam para assimetrias com relação à utilização do Twitter pelas campanhas com maior e menor volume de recursos, existente no ambiente tradicional das campanhas políticas. Além disso, verificaram-se diferenças na atuação dos principais candidatos envolvidos no pleito, tendo os candidatos em maior vantagem junto ao eleitorado adotado posturas mais conservadoras. Na maioria dos candidatos, constatou-se o baixo índice de mensagens destinadas à mobilização dos internautas. São ressaltadas as estratégias mais inovadoras, em especial aquelas adotadas pelo candidato Marcelo Freixo, bem sucedidas em termos de mobilização de eleitores.

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The finite difference time domain (FDTD) method has direct applications in musical instrument modeling, simulation of environmental acoustics, room acoustics and sound reproduction paradigms, all of which benefit from auralization. However, rendering binaural impulse responses from simulated
data is not straightforward to accomplish as the calculated pressure at FDTD grid nodes does not contain any directional information. This paper addresses this issue by introducing a spherical array to capture sound pressure on a finite difference grid, and decomposing it into a plane-wave density
function. Binaural impulse responses are then constructed in the spherical harmonics domain by combining the decomposed grid data with free field head-related transfer functions. The effects of designing a spherical array in a Cartesian grid are studied, and emphasis is given to the relationships
between array sampling and the spatial and spectral design parameters of several finite-difference
schemes.

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Due to its efficiency and simplicity, the finite-difference time-domain method is becoming a popular choice for solving wideband, transient problems in various fields of acoustics. So far, the issue of extracting a binaural response from finite difference simulations has only been discussed in the context of embedding a listener geometry in the grid. In this paper, we propose and study a method for binaural response rendering based on a spatial decomposition of the sound field. The finite difference grid is locally sampled using a volumetric array of receivers, from which a plane wave density function is computed and integrated with free-field head related transfer functions, in the spherical harmonics domain. The volumetric array is studied in terms of numerical robustness and spatial aliasing. Analytic formulas that predict the performance of the array are developed, facilitating spatial resolution analysis and numerical binaural response analysis for a number of finite difference schemes. Particular emphasis is placed on the effects of numerical dispersion on array processing and on the resulting binaural responses. Our method is compared to a binaural simulation based on the image method. Results indicate good spatial and temporal agreement between the two methods.