258 research outputs found

    Intense tera-hertz laser driven proton acceleration in plasmas

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    We investigate the acceleration of a proton beam driven by intense tera-hertz (THz) laser field from a near critical density hydrogen plasma. Two-dimension-in-space and three-dimension-in-velocity particle-in-cell simulation results show that a relatively long wavelength and an intense THz laser can be employed for proton acceleration to high energies from near critical density plasmas. We adopt here the electromagnetic field in a long wavelength (0.33 THz) regime in contrast to the optical and/or near infrared wavelength regime, which offers distinct advantages due to their long wavelength (k ¼ 350 lm), such as the k2 scaling of the electron ponderomotive energy. Simulation study delineates the evolution of THz laser field in a near critical plasma reflecting the enhancement in the electric field of laser, which can be of high relevance for staged or post ion acceleration

    Influence of municipal socioeconomic indices on mortality rates for oral and oropharyngeal cancer in older adults in the State of São Paulo, Brazil

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    O câncer de boca e o câncer de orofaringe são doenças influenciadas por fatores socioeconômicos. O risco de desenvolver essas doenças aumenta com a idade, e a maioria dos casos ocorre em idosos, com elevadas taxas de mortalidade. O objetivo deste estudo foi analisar a influência dos índices socioeconômicos municipais nas taxas de mortalidade por câncer de boca (CB) e de orofaringe (CO) em idosos nas 645 cidades do estado de São Paulo, Brasil, nos anos de 2013 a 2015. Dados secundários de óbitos foram obtidos pelo Sistema de Informações sobre Mortalidade (SIM) do Ministério da Saúde. O número de idosos e os valores da renda média per capita e do índice de desenvolvimento humano por município (IDH-M) foram obtidos a partir dos dados da Fundação SEADE. Realizou-se a análise descritiva e exploratória dos dados, seguida de modelos binomiais negativos descritos pelo procedimento PROC GENMOD e avaliados pelo critério de informação de Akaike corrigido (AICc), pelo grau de liberdade e pelo teste de Wald (α=0,05). Cerca de 30% das cidades notificaram óbitos em 2013, 16,74% em 2014 e 18,61% em 2015. Astaxas médias de mortalidade por CB e CO foram, respectivamente, de 20,0 (± 30,9) e 10,7 (± 17,5) por 100 mil habitantes. A renda média variou de R434,20aR 434,20 a R 2.009,00 e o IDH-M, de 0,65 a 0,89. Houve decréscimo significativo (p < 0,05) nas taxas de mortalidade por CB e CO em idosos com o aumento dos valores das rendas médias e do IDH-M. As desigualdades socioeconômicas das cidades influenciam nas taxas de mortalidade por CB e CO em idosos22Oral and oropharyngeal cancer are diseases strongly influenced by socioeconomic factors. The risk of developing these diseases increases with age and most cases occur in the elderly, with higher mortality rates. This study aimed to analyze the influence of municipal socioeconomic indices on mortality rates for oral (OC) and oropharyngeal cancer (OPC) in elderly residents from 645 cities in the State of São Paulo, Brazil, from 2013 to 2015. Secondary data on deaths were obtained in the Mortality Information System from the Brazilian Ministry of Health. The number of elderly, as well as per capita median income values and Human Development Index by municipality (HDI-M) values were obtained from data by the SEADE Foundation. Descriptive and exploratory analysis of data was performed, followed by negative binomial models described by the Proc Genmod procedure and evaluated by the corrected AIC (Akaike Information Criterion), the likelihood level, and the Wald test (α = 0.05). Around 30% of the cities notified deaths in 2013, 16.74% in 2014, and 18.61% in 2015. Founded mortality mean rates from OC and OPC were, respectively, 20.0 (± 430.9) and 10.7 (± 17.5) deaths per 100,000 inhabitants. Mean income ranged, in local currency, from 434.2 to 2,009.00. HDI-M ranged from 0.65 to 0.89. There was a significant decrease (p < 0.05) in mortality rates for OC and OPC in elderly with the increase in the cities’ mean income and HDI-M values. Socioeconomic inequalities in the cities the on mortality rates for OC and OPC in elderly resident

    Peak Oil:Die Herausforderung lokaler Erdölabhängigkeit am Beispiel Münster

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    Das Erdölzeitalter neigt sich dem Ende zu – daran ändern auch Schieferöle, Agrartreibstoffe oder Verfahren wie das Fracking langfristig nichts. Einer Gruppe von Studierenden an der Uni Münster ging die wissenschaftliche, politische und gesellschaftliche Beschäftigung mit dieser Herausforderung zu langsam. Aus diesem Grund initiierte sie 2012 eigenständig ein interdisziplinäres Peak-Oil-Seminar und begleitete Studierende dabei, in gesellschaftsrelevanten Sektoren der Energieversorgung, des Transports, der lokalen Wirtschaft, der Ernährung, der Gesundheit und der privaten Haushalte eigene Fragestellungen zu entwickeln und diesen nachzugehen. Das Ergebnis ist ein Bericht, der am Beispiel Münster die Brisanz und Aktualität knapper werdender Ressourcen herausstreicht, der die Wichtigkeit der lokalen, vorausschauenden und freiwillig-kreativen Verringerung der Öl-Abhängigkeit hervorhebt und der nicht zuletzt eine Lanze bricht für Formate transformativen und offenen Forschens und Handelns. <br

    O regime pluviométrico do estado do Tocantins, Brasil:: variações espaciais

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    O presente estudo trata do regime das chuvas no estado do Tocantins, na Região Norte do Brasil, tomando como recorte temporal o período de 1986 a 2005. O conhecimento do comportamento de elementos climáticos, como a precipitação, é fundamental para as atividades humanas e para o ordenamento do território, tais como agricultura, abastecimento urbano e empreendimentos hidroenergéticos. Foram selecionadas 16 estações pluviométricas da Agência Nacional das Águas (ANA) e do Instituto Nacional de Meteorologia (INMET), distribuídos ao longo do estado do Tocantins, cujos dados foram analisados na forma de pluviogramas. Os resultados revelam que o período chuvoso se estende de Outubro a Abril, tendo como meses mais chuvosos dezembro, janeiro e março. O período mais seco vai de Maio a Setembro, sendo junho, julho e agosto os meses com menor quantidade de chuvas, desse trimestre, agosto é o mês com menor contribuição para as chuvas anuais no período analisado (1986-2005)

    Implications of Edentulism on Quality of Life among Elderly

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    This study aimed was to test the association between quality of life and edentulism among elderly individuals in a city in southeastern Brazil. This cross-sectional study was carried out with 163 individuals aged 60 years or older, functionally independent and non-institutionalized. Data were collected with a questionnaire and oral examination. The edentulism was the dependent variable. The independent variables were sex, age, household income and quality of life (WHOQOL-Old) and their scores. To assess the association between the dependent variable and independent variables was used bivariate analysis (p < 0.10). Poisson regression model was performed, adjusting for age and sex. The average age of participants was 69 years (± 6.1), 68.7% were female and 52.8% were diagnosed as completely edentulous (90% CI: 0.33–1.24). When the independent variables were associated to the prevalence of edentulism, statistically significant associations were found for age (p = 0.03) and social participation dimension of the WHOQOL-Old (p = 0.08). In the Poisson regression, social participation remained statistically associated to edentulism {RP = 2.12 [90% CI (1.10–4.00)]}. The social participation proved to have a significant association to edentulism, thereby attesting to the negative effect of this condition on social aspects

    High-energy terahertz pulses from semiconductors pumped beyond the three-photon absorption edge

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    A new route to efficient generation of THz pulses with high-energy was demonstrated using semiconductor materials pumped at an infrared wavelength sufficiently long to suppress both two- and three-photon absorption and associated free-carrier absorption at THz frequencies. For pumping beyond the three-photon absorption edge, the THz generation efficiency for optical rectification of femtosecond laser pulses with tilted intensity front in ZnTe was shown to increase 3.5 times, as compared to pumping below the absorption edge. The four-photon absorption coefficient of ZnTe was estimated to be β₄=(4±1)×10⁻⁵ cm⁵/GW³. THz pulses with 14 μJ energy were generated with as high as 0.7% efficiency in ZnTe pumped at 1.7 µm. It is shown that scaling the THz pulse energy to the mJ level by increasing the pump spot size and pump pulse energy is feasible
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