98 research outputs found

    Smolyak's algorithm: A powerful black box for the acceleration of scientific computations

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    We provide a general discussion of Smolyak's algorithm for the acceleration of scientific computations. The algorithm first appeared in Smolyak's work on multidimensional integration and interpolation. Since then, it has been generalized in multiple directions and has been associated with the keywords: sparse grids, hyperbolic cross approximation, combination technique, and multilevel methods. Variants of Smolyak's algorithm have been employed in the computation of high-dimensional integrals in finance, chemistry, and physics, in the numerical solution of partial and stochastic differential equations, and in uncertainty quantification. Motivated by this broad and ever-increasing range of applications, we describe a general framework that summarizes fundamental results and assumptions in a concise application-independent manner

    Novas estrategias de pesquisa e desenvolvimento na producao integrada de frutas (PIF): 1. projeto de pesquisa em produção integrada de manga.

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    O artigo aborda a produção de manga no Brasil, a demanda por esta fruta no mercado externo e propõe a realização de um projeto de pesquisa no sentido de Implantar o Sistema de Acompanhamento da Produção Integrada (SAPI) a produtores de manga do Brasil, a partir de estudos realizados na área piloto localizada na região do Submédio do Rio São Francisco

    Projeto de pesquisa em produção integrada de uvas finas de mesa.

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    O artigo aborda a produção de uva de mesa no Brasil, a demanda por esta fruta no mercado externo e propõe a realização de um projeto de pesquisa no sentido de Implantar o Sistema de Acompanhamento da Produção Integrada (SAPI) a produtores de uva do Brasil, a partir de estudos realizados na área piloto localizada na região do Submédio do Rio São Francisco

    Knowledge of risk factors, beliefs and practices of female healthcare professionals towards breast cancer in a tertiary institution in Lagos, Nigeria

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    <p>Abstract</p> <p>Background</p> <p>Breast cancer is the leading female malignancy in Nigeria. Screening for early detection has led to reduction in mortality from the disease. It is known that attitudes of physicians and motivation by community nurses influence uptake of screening methods by women. This study aims to investigate knowledge of breast cancer risk factors, beliefs about treatment and practice of screening methods among a cohort of female healthcare professionals in Lagos, Nigeria.</p> <p>Methods</p> <p>A cross-sectional study was conducted using a self-administered questionnaire to assess the knowledge of breast cancer risk factors, beliefs about treatment and practice of screening methods among 207 female doctors, nurses and other healthcare professionals working in a university teaching hospital in Lagos, Nigeria. Stratified random sampling method was employed. Chi square test, analysis of variance and Mantel-Haenszel test were performed in data analysis using SPSS v10.0 and Epi Info version 6 statistical packages.</p> <p>Results</p> <p>Female doctors obtained a mean knowledge score of 74% and were the only professional group that had satisfactory knowledge of risk factors. Majority (86%) believed that early breast cancer is curable while half of participants believed that prayer can make breast cancer disappear from the affected breast. Eighty three percent practice breast self-examination (BSE) once a month and only 8% have ever had a mammogram. Age, knowledge of risk factors, profession and beliefs were not significantly associated with rate of BSE in this study.</p> <p>Conclusion</p> <p>Results from this study suggest the need for continuing medical education programmes aimed at improving knowledge of breast cancer among female healthcare providers other than doctors.</p

    Left ventricular volume: an optimal parameter to detect systolic dysfunction on prospectively triggered 64-multidetector row computed tomography: another step towards reducing radiation exposure

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    In this study, we define the correlation between LV volumes (both LV end-diastolic volume [LVEDV] and LV end-systolic volume [LVESV]) and ejection fraction (EF) on 64 slice multi-detector computed tomography (MDCT). We also determine the accuracy of all the LV volume (LVV) parameters to detect LV systolic dysfunction (LVSD) and investigate the feasibility of using LVV as a surrogate of LVSD on prospectively gated imaging to prevent the radiation exposure of retrospective imaging. 568 patients undergoing 64-detector MDCT were divided into 2 groups: Group 1—subjects without any heart disease and LVEF ≥ 50%; and Group 2—patients with coronary artery disease and LVEF < 50% (defined as LVSD). The LVV (LV cavity only) and Total LV volume (cavity + LV mass) at end-systole and end-diastole (LVESV, Total LVESV, LVEDV and Total LVEDV) were measured. The upper limit values (mean + 2 SD) of all LVV parameters in Group 1 were used as the reference criterion to diagnose LVSD in Group 2. An exponential correlation was found between LVEF and all the LVV parameters. The specificity to detect LVSD in Group 2 was >90% and the sensitivity was 88.9, 83.3, 61.3 and 74.9% by using LVESV, Total LVESV, LVEDV and Total LVEDV, respectively. Systolic and diastolic LV volumes had a high correlation with LVEF and a high accuracy to detect LVSD. Thus, on prospectively triggered imaging, ventricular volumes can predict patients with reduced LVEF, and appropriate referrals can be made

    End-stage renal disease in young black males in a black-white population: longitudinal analysis of the Bogalusa Heart Study

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    <p>Abstract</p> <p>Background</p> <p>Risk factors in childhood create a life-long burden important in the development of cardiovascular (CV) disease in adulthood. Many risk factors for CV disease (e.g., hypertension) also increase the risk of renal disease. However, the importance of childhood risk factors on the development of chronic kidney disease and end-stage renal disease (ESRD) is not well characterized.</p> <p>Methods</p> <p>The current observations include data from Bogalusa Heart Study participants who were examined multiple times as children between 1973 and 1988.</p> <p>Results</p> <p>Through 2006, fifteen study participants subsequently developed ESRD in adulthood; seven with no known overt cause. Although the Bogalusa Heart Study population is 63% white and 37% black and 51% male and 49% female, all seven ESRD cases with no known overt cause were black males (p < 0.001). Mean age-adjusted systolic and diastolic blood pressure in childhood was higher among the ESRD cases (114.5 mmHg and 70.1 mmHg, respectively) compared to black (103.0 mmHg and 62.3 mmHg, respectively) and white (mean = 103.3 mmHg and 62.3 mmHg, respectively) boys who didn't develop ESRD. The mean age-adjusted body mass index in childhood was 23.5 kg/m<sup>2 </sup>among ESRD cases and 18.6 kg/m<sup>2 </sup>and 18.9 kg/m<sup>2 </sup>among black and white boys who didn't develop ESRD, respectively. Plasma glucose in childhood was not significantly associated with ESRD.</p> <p>Conclusion</p> <p>These data suggest black males have an increased risk of ESRD in young adulthood. Elevated body mass index and blood pressure in childhood may increase the risk for developing ESRD as young adults.</p

    Projeto de pesquisa em produção integrada de uvas finas de mesa.

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    O artigo aborda a produção de uva de mesa no Brasil, a demanda por esta fruta no mercado externo e propõe a realização de um projeto de pesquisa no sentido de Implantar o Sistema de Acompanhamento da Produção Integrada (SAPI) a produtores de uva do Brasil, a partir de estudos realizados na área piloto localizada na região do Submédio do Rio São Francisco.Editado por Gilmar Ribeiro Nachtigall, Ana Beatriz Costa Czermainski

    Novas estrategias de pesquisa e desenvolvimento na producao integrada de frutas (PIF): 1. projeto de pesquisa em produção integrada de manga.

    Get PDF
    O artigo aborda a produção de manga no Brasil, a demanda por esta fruta no mercado externo e propõe a realização de um projeto de pesquisa no sentido de Implantar o Sistema de Acompanhamento da Produção Integrada (SAPI) a produtores de manga do Brasil, a partir de estudos realizados na área piloto localizada na região do Submédio do Rio São Francisco.Editado por Gilmar Ribeiro Nachtigall, Ana Beatriz Costa Czermainski
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