905 research outputs found

    Late prematurity: a systematic review

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    AbstractObjectivethis study aimed to review the literature regarding late preterm births (34 weeks to 36 weeks and 6 days of gestation) in its several aspects.Sourcesthe MEDLINE, LILACS, and Cochrane Library databases were searched, and the references of the articles retrieved were also used, with no limit of time.Data synthesisnumerous studies showed a recent increase in late preterm births. In all series, late preterm comprised the majority of preterm births. Studies including millions of births showed a strong association between late preterm birth and neonatal mortality. A higher mortality in childhood and among young adults was also observed. Many studies found an association with several neonatal complications, and also with long-term disorders and sequelae: breast-feeding problems, cerebral palsy, asthma in childhood, poor school performance, schizophrenia, and young adult diabetes. Some authors propose strategies to reduce late preterm birth, or to improve neonatal outcome: use of antenatal corticosteroids, changes in some of the guidelines for early delivery in high-risk pregnancies, and changes in neonatal care for this group.Conclusionsnumerous studies show greater mortality and morbidity in late preterm infants compared with term infants, in addition to long-term disorders. More recent studies evaluated strategies to improve the outcomes of these neonates. Further studies on these strategies are needed

    Produtividade e custos do processador trabalhando em povoamentos de Eucalyptus grandis Hill ex Maiden.

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    In the present work a time study was conducted with the objective of adjusting equations to estimate the time of activities, productivity, operational costs and the production of the processor used in a harvest operation of stands of Eucalyptus grandis in plain topography in the state of Bahia, Brazil. The operational cycle of the processor consisted of the time spent to process a tree, and was divided in to stages, which were assessed using the methotodology of single activity times. The sampling unit was the operational cycle of the machine. The statistical analysis was based on regression analysis considering the selection procedure “stepwise”. With the adjusted equations it was possible to estimate the productivity of the machine taking into account the of tree diameter. Considering an operational efficiency of 70 % under the circumstances of the study, the productivity of the processor was 25,8 m3 cc/h, the operational costs 47,90 US/handtheproductioncosts1,86US/h and the production costs 1,86 US/m3 cc. On the basis of the obtained results it can be concluded that the time of tree processing has varied directly according to the diameter increase diameter; the preparation time, contrary to the processing time, only shows a weak correlation with tree diameter; productivity of the processor is directly proportional to tree diameter, when expressed in volume and inversely proportional when expressed in tree number; the costs per cubic meter of wood processed varies inversely with of increased diameter; from the operational costs, fixed costs had the highest proportion followed by the variable costs, administrative costs and costs for manpower; the production costs of the processor decreased exponentially with increasing tree diameter.No presente trabalho foi realizado um estudo de tempos com o objetivo de ajustar equações para estimar o tempo das atividades, a produtividade, o custo operacional e da produção do processador utilizado em um sistema de colheita de madeira de povoamentos de Eucalyptus grandis Hill ex Maiden, em topografia plana, no Estado da Bahia. O ciclo operacional do processador consistiu no tempo gasto para processar uma árvore e foi dividido em etapas as quais foram cronometradas, usando a metodologia dos tempos individuais. A unidade amostral foi constituída do ciclo operacional da máquina. A análise estatística baseou-se em estudo de regressão, sendo utilizado o procedimento de modelagem de regressão "stepwise". Com as equações ajustadas, foi possível estimar a produtividade da máquina em função do diâmetro das árvores. Nas condições do estudo, considerando uma eficiência operacional de 70%, a produtividade do processador foi de 25,8 m³cc/h, o custo operacional 47,90 US/heocustodeproduc\ca~ode1,86US/h e o custo de produção de 1,86 US/m³cc. Com base nos resultados obtidos, pode-se concluir que: o tempo de processamento das árvores varia diretamente com o aumento do diâmetro; o tempo de preparação, ao contrário do tempo de processamento, possui uma baixa correlação com o diâmetro das árvores; a produtividade do processador é diretamente proporcional ao aumento do diâmetro das árvores, quando expressa em volume, e inversamente proporcional, quando expressa em número de árvores; o custo por metro cúbico de madeira processada com processador, varia numa relação inversa ao aumento do diâmetro; do custo operacional do processador, o custo fixo é o de maior proporção, seguido do custo variável, administrativo e da mão-de-obra; e, o custo de produção do processador diminui em forma exponencial com o aumento do diâmetro das árvores

    Exame Nacional de Desempenho de Estudantes (ENADE): contributo dos eixos de formação específica na performance dos cursos de administração entre IES públicas e privadas em Minas Gerais

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    Este estudo teve como objetivo verificar, dentre as IES com os melhores resultados no Enade de 2015, quais eixos de formação específica mais contribuíram para o desempenho do exame dos Cursos de Administração e se existe diferença significativa nos resultados obtidos entre as IES Privadas e Públicas de Minas Gerais.  Para isso, foram utilizados recursos de estatística descritiva, tais como análise de dispersão, medidas de posicionamento, histograma e gráfico blox plot sobre as Notas dos Concluintes (NCc) obtidas por cada curso. Foi também realizado o Teste t  Student para averiguar a hipótese de haver diferenças significativas entre as médias das NCc de IES Públicas e Privadas dos Cursos de Administração de melhor desempenho no Enade em Minas Gerais. Os resultados estatísticos encontrados demonstram a existência de uma elevada dispersão nas NCc dos Cursos de Administração no Brasil e em Minas Gerais. Revelaram também que 36,5% dos cursos de Administração atingiram resultados insatisfatórios, conceito ≤ 2 no Enade de 2015 e apenas 4,9% obtiveram conceito 5. Esses Cursos com elevado conceito se destacaram nos seguintes eixos de formação específica: financeira e orçamentária; materiais, produção e logística; planejamento estratégico e sistema de informações. Por fim, o estudo demonstra existir uma diferença estatisticamente significativa entre as notas das IES Públicas e Privadas de melhores desempenho no ENADE (conceito ≥ 4) no Estado de Minas Gerais. &nbsp

    New distributional records of Mecoptera (Insecta) from Colombia

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    We present new distributional records for two Colombian species of Bittacidae. Pazius convolutus García-García & Cadena-Castañeda, 2015 and Bittacus panamensis Byers, 1958 previously known from Cundinamarca department are herein newly recorded from Santander and Magdalena, respectively. In addition, we recorded Bittacus pignatelli Navás, 1932 in Colombia for the first time, increasing the number of species of Mecoptera in the country. Comments about mating behavior of P. convolutus, as well as a distribution map and a check-list of Colombian species of Mecoptera are included

    Integral transforms solution for flow development in wavy wall ducts

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    Purpose – The purpose of this paper is to provide an analysis of two‐dimensional laminar flow in the entrance region of wavy wall ducts as obtained from the solution of the steady Navier‐Stokes equations for incompressible flow. Design/methodology/approach – The study is undertaken by application of the generalized integral transform technique in the solution of the steady Navier‐Stokes equations for incompressible flow. The streamfunction‐only formulation is adopted, and a general filtering solution that adapts to the irregular contour is proposed to enhance the convergence behavior of the eigenfunction expansion. Findings – A few representative cases are considered more closely in order to report some numerical results illustrating the eigenfunction expansions convergence behavior. The product friction factor‐Reynolds number is also computed and compared against results from discrete methods available in the literature for different Reynolds numbers and amplitudes of the wavy channel. Research limitations/implications – The proposed methodology is fairly general in the analysis of different channel profiles, though the reported results are limited to the wavy channel configuration. Future work should also extend the analysis to geometries represented in the cylindrical coordinates with longitudinally variable radius. Practical implications – The error‐controlled converged results provide reliable benchmark results for the validation of numerical results from computational codes that address the solution of the Navier‐Stokes equations in irregular geometries. Originality/value – Although the hybrid methodology is already known in the literature, the results here presented are original and further challenges application of the integral transform method in the solution of the Navier‐Stokes equations.Indisponível

    Experiments and Simulations of Laminar Forced Convection With Water–Alumina Nanofluids in Circular Tubes

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    This work reports fundamental experimental-theoretical research related to heat transfer enhancement in laminar channel flow with nanofluids, which are essentially modifications of the base fluid with the dispersion of metal oxide nanoparticles. The nanofluids were synthesized by a two-step approach, using a dispersant and an ultrasound probe or a ball mill for alumina nanoparticles dispersion within the aqueous media. The theoretical work involves the proposition of an extension of the thermally developing flow model that accounts for the temperature variation of all the thermophysical properties, including viscosity and the consequent variation of the velocity profiles along the thermal entry region. The simulation was performed by making use of mixed symbolic-numerical computation on the Mathematica 7.0 platform and a hybrid numerical-analytical methodology (generalized integral transform technique, GITT) in accurately handling the governing partial differential equations for the heat and fluid flow problem formulation with temperature dependency in the thermophysical properties. Experimental work was also undertaken based on a thermohydraulic circuit built for this purpose, and sample results are presented to verify the proposed model. The aim is to confirm that both the constant properties and temperature-dependent properties models, besides available correlations previously established for ordinary fluids, provide adequate prediction of the heat transfer enhancement observed in laminar forced convection with such nanofluids and within the experimented Reynolds number range.Indisponível

    Integral transform solution of the Navier–Stokes equations in full cylindrical regions with streamfunction formulation

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    A hybrid numerical–analytical solution based on the generalized integral transform technique is proposed to handle the two‐dimensional Navier–Stokes equations in cylindrical coordinates, expressed in terms of the streamfunction‐only formulation. The proposed methodology is illustrated in solving steady‐state incompressible laminar flow of Newtonian fluids in the developing region of a circular tube. The flow modeling also considers two limiting inlet conditions, namely, uniform velocity profile representing a parallel flow, and zero vorticity that characterizes irrotational inlet flow. The integral transform analysis for such a full cylindrical region brings up singularities at the channel centerline, and, as previously described in a work dealing with the boundary‐layer formulation, a way to alleviate this difficulty is to adopt a recently introduced fourth‐order eigenvalue problem as the basis for the eigenfunction expansion. A thorough convergence analysis of the proposed expansion is then undertaken, for different values of Reynolds number, and a set of reference results for the velocity distributions and friction factors are then presented in tabular and graphical forms.Indisponível

    PRIMING EM MATRIZ SÓLIDA DE SEMENTES DE CAFÉ ARMAZENADAS COM ALTA UMIDADE

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    The water content of seeds and temperature affect the biological processes, determining different results when seeds areexposed to different levels of these factors. When seeds are subjected to priming, we expect improvement in the physiological qualityof seeds, but while promising, this procedure is still in the experimental phase in coffee seeds. In order to evaluate the effects of solidmatrix priming at three different temperatures to evaluate the performance of coffee seeds (Coffea arabica L.) stored for up to twelvemonths, we carried out this research at the Central Laboratory of Seed Analysis in the Agriculture Department, Universidade Federalde Lavras, Lavras - MG. Seeds with 36.0% moisture content were sorted, processed, packed in polyethylene bags and kept in coldstorage for up to 12 months. At quarterly intervals, the seed samples were subjected to solid matrix priming, at temperatures of 20 °C,30 °C and 40 °C for 6 days. One control, without priming, was also evaluated. The physiological conditioning of solid matrix primingof C. Arabica seeds, held for 6 days at 20 °C and 30 °C favors the emergence of seedlings in seeds stored for 9 months and under 40°C, is harmful to the C. arabica seeds.O conteúdo de água das sementes e a temperatura afetam os processos biológicos, determinando variados resultadosquando as sementes são submetidas a diferentes níveis desses fatores. Quando as sementes são submetidas ao priming, esperam-serespostas em razão da melhoria na qualidade fisiológica dessas sementes, mas, embora promissor, esse procedimento ainda seencontra em fase experimental em sementes de café. Com objetivo de avaliar os efeitos do priming em matriz sólida em três diferentestemperaturas sobre o desempenho de sementes de café (Coffea arabica L.) armazenadas por até doze meses, realizou-se a presentepesquisa no Laboratório Central de Análise de Sementes do Departamento de Agricultura da Universidade Federal de Lavras, Lavras –MG. Sementes com 36,0% de umidade foram classificadas, tratadas, acondicionadas em embalagens de polietileno e armazenadas emcâmara fria por até 12 meses. Em intervalos trimestrais, as amostras de sementes foram submetidas ao priming em matriz sólida, emtemperaturas de 20 oC, 30 oC e 40 oC, por 6 dias. Uma testemunha, sem priming, foi também avaliada. O condicionamento fisiológicoem matriz sólida de sementes de C. arabica. realizado por 6 dias nas temperaturas de 20 °C e 30 °C favorece a emergência de plântulasem sementes armazenadas por 9 meses e, sob temperatura de 40 °C, é prejudicial às sementes de C. arabic

    Overview of DNA Repair in Trypanosoma cruzi, Trypanosoma brucei, and Leishmania major

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    A wide variety of DNA lesions arise due to environmental agents, normal cellular metabolism, or intrinsic weaknesses in the chemical bonds of DNA. Diverse cellular mechanisms have evolved to maintain genome stability, including mechanisms to repair damaged DNA, to avoid the incorporation of modified nucleotides, and to tolerate lesions (translesion synthesis). Studies of the mechanisms related to DNA metabolism in trypanosomatids have been very limited. Together with recent experimental studies, the genome sequencing of Trypanosoma brucei, Trypanosoma cruzi, and Leishmania major, three related pathogens with different life cycles and disease pathology, has revealed interesting features of the DNA repair mechanism in these protozoan parasites, which will be reviewed here
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