2,904 research outputs found

    Ex-Convicts Face Multiple Labor Market Punishments: Estimates of Peer-Group and Stigma Effects Using Equations of Returns to Schooling

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    We produced a data set from a survey of a population of convicts in probation. We combined this new data set with an official data set from the Brazilian government to study labor market discrimination faced by ex-convicts. We were interested in estimating two potential effects of discrimination, statistical (stigma) and behavioral (peer-group) effects. Our econometric results suggest that stigmatization leads to a 39% reduction in the wage earned by ex-convicts relative to the wage earned by non-convicts. They also suggest that the peer-group effect accounts for a reduction in the relative earnings of ex-convicts of 1.1% per year of study. In addition, we also show that ex-convicts earn 3.1% less per year of experience than non-convicts.Stigma Effect, Peer Effect, Crime Rate, Returns to Schooling, Wage Discrimination

    Water diffusion in rough carbon nanotubes

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    We use molecular dynamics simulations to study the diffusion of water inside deformed carbon nanotubes with different degrees of deformation at 300 K. We found that the number of hydrogen bonds that water forms depends on nanotube topology, leading to enhancement or suppression of water diffusion. The simulation results reveal that more realistic nanotubes should be considered to understand the confined water diffusion behavior, at least for the narrowest nanotubes, when the interaction between water molecules and carbon atoms is relevant.Comment: 17 pages, 8 figure

    Diffusion behavior of water confined in deformed carbon nanotubes

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    We use molecular dynamics simulations to study the diffusion of water inside deformed carbon nanotubes, with different degrees of eccentricity at 300K. We found a water structural transition between tubular-like to single-file for the (7,7) nanotubes associated with a change from a high to low mobility regimes. The water which in the undeformed (9,9) nanotubes is frozen, becomes liquid for the distortion above a certain threshold. These water diffusion enhancement (suppresion) is related to a reduction (increase) in the number of hydrogen bonds. This suggests that the shape of the nanotube is a particularly important ingredient when considering the dynamical and structural properties of confined water.Comment: 16 pages, 9 figure

    Caracterização físico-química de amostras de méis produzidas por Apis mellifera L. em fragmento de cerrado no município de Itirapina, São Paulo.

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    A fisionomia vegetal mais representativa do país, depois da floresta amazônica, é o cerrado, que ocupa atualmente dois milhões de km2 do território brasileiro. Este trabalho teve como objetivo determinar as características físicoquímicas de amostras de mel produzidas por Apis mellifera em um fragmento de cerrado, localizado em Itirapina, SP (22º14?S e 47º49?W). As amostras foram coletadas mensalmente, em cinco colméias, entre fevereiro e outubro de 2005 e as características avaliadas foram: açúcares redutores, redutores totais, sacarose, umidade, hidroximetilfurfural (HMF), cor, condutividade elétrica, pH, acidez, índice de formol, teor de cinzas, proteínas e viscosidade, além da análise polínica. Os resultados obtidos indicam que os limites estabelecidos pela legislação brasileira para parâmetros físico-químicos analisados são atendidos pela maioria das amostras de mel. Com relação à análise polínica, foi verificada a presença de Eucalyptus sp. como pólen dominante nos meses de fevereiro a julho e o de Citrus sp. no mês de outubro, em virtude da maior atratividade destes dois cultivos sobre as abelhas

    Duração da estacionalidade de produção em pastagens irrigadas.

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    O objetivo deste trabalho foi caracterizar o período de estacionalidade de produção de matéria seca de seis espécies forrageiras irrigadas. p. PURPUREUM CV Toiwan; P. maximum cv Tanzânia; B. decumbens cv Basilisk; B. brizantha cv Marandu; P. atrtum cv Pojuca; C. doctylon cv Coast-cross. Durante dois anos (1999/2000 e 2000/2001), avaliaram-se as condições climáticas do local onde o experimento foi realizado (região Central do Estado de São Paulo, São Carlos) e as características fenológicas das forrageiras, em São Carlos - SP. As pastagens irrigadas têm um período de 65 a 70 dias de estacionalidade de produção durante o ano, em que, mesmo satisfazendo as necessidades hídricas da planta forrageira, não há produção de matéria seca

    Low-cost multi-spectral camera platform for in-flight near real-time vegetation index computation and delivery.

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    Agricultural optimization and increased productivity is always a growing concern, due to the increasing population. Crops susceptible to a wide variety of hindering conditions, need to be carefully observed and managed to guarantee maximum production. Many diseases, weather changes, soil variances and other in?uencing factors are only visible after the plant has reached a deplorable state and its neighbors closely trailing behind. Ongoing research is enhancing an observation model that can better prevent such factors, but many still present a variety of limiting factors that are still being studied. Vegetation indices is a long dated studied concept that has proven to be able to show plant response to stress before visible signs are present. To take advantage of this we propose a multi-spectral camera, aimed at mass use, to provide the needed observation with top of the line, reliable results. The built prototype was put through two different tests, both showing it capable of displaying plant health. The ?ne control test showed the camera capable of displaying difference in plant health after only two days of stress. The results were reached with out the use of expensive lenses/?lters, and provide easy to interpret results. All while being able to send data to a nearby portable device
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