1000 resultados para Espalhamento dinâmico da luz
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Cet article cherche à dresser, sous la perspective historique, le bilan de la situation des pays périphériques dans les dernières trentes années. Pour cela, il aborde particulièrement les enjeux du développement dans la phase de la globalisation du capital. Ce travail s'appuie surtout sur les études de la vaste bibliographie publiée récemment. Dans quelle mesure la relance du développement concernant plusieurs secteurs stagnés de la périphérie deviendrait-elle une réelle possibilité? Autour de cette question, que nous trouvons centrale dans l'actuelle conjoncture, nous entamons quelques réflexions. Nous envisageons montrer que la stagnation économique à laquelle des nombreux pays non développés font face ne découle pas en partie d'une crise sociale et économique ouverte dans les années soixante-dix et qui s'élargit jusqu'à nos jours malgré les tentatives de restructuration de la société capitaliste. Les stratégies et les mesures politiques à caractère néo-liberal aussi auraient énormément contribué à cette situation étant donné qu'elles ont renforcé les amarres financières qui ont étranglé pour une part les économies périphériques. Outre ces difficultés, ces pays affronteraient les limites écologiques du capitalisme. La relance du développement dans un nouveau stade exigeant la croissance économique, la justice sociale et la préservation de la nature amènerait à une rupture face au capitalisme.
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O objetivo deste trabalho foi determinar o tempo ótimo de escarificação das sementes de Senna alata em ácido sulfúrico e verificar o efeito da temperatura, em condição de luz e escuro, na germinação de sementes dessa espécie. As sementes foram imersas em ácido sulfúrico concentrado por períodos de 0, 15, 30 e 60 minutos, e o teste de germinação realizado em BOD a 25ºC, utilizando quatro repetições de 50 sementes em cada período de tempo, sendo o delineamento estatístico inteiramente casualizado com 4 tratamentos. No segundo experimento, para verificar o efeito da temperatura e da condição de luz mais adequada a germinação, utilizou-se temperaturas de 10 a 45ºC, com intervalos de 5ºC, em condição de luz fluorescente branca ou escuro contínuo (gerbox preto). Utilizou-se o delineamento experimental inteiramente casualizado, disposto em esquema fatorial 8x2, com 4 repetições, de 50 sementes cada. em todos os testes as avaliações da porcentagem e índice de velocidade de germinação foram feitas diariamente, durante 10 dias, onde as sementes foram consideradas germinadas quando apresentaram 2 mm de raiz. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey a 5% de probabilidade. A escarificação do tegumento com ácido sulfúrico durante 60 minutos, foi ideal para as sementes de Senna alata, por proporcionar maiores valores na porcentagem e velocidade de germinação. A germinação ocorre entre 15 e 40ºC, sendo consideradas fotoblásticas neutras entre 20 e 40ºC e fotoblásticas negativas preferenciais a 15ºC. O melhor desempenho germinativo foi obtido nas temperaturas de 25, 30 e 35ºC, onde ocorreram maior porcentagem e velocidade de germinação.
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The morphology of the midgut epithelium cells of Anticarsia gemmatalis (Hübner) larvae is described by light and transmission electron microscopy. The midgut of A. gemmatalis is the largest portion of the digestive tract, with three distinct regions: proximal, media and distal. Its wall is formed by pseudostratified columnar epithelial tissue having four cell types: columnar, goblet, regenerative, and endocrine cells. The columnar cells are numerous and long, with the apical portion showing many lengthy microvilli and the basal portion invaginations forming a basal labyrinth. The goblet cells have a large goblet-shaped central cavity delimited by cytoplasmic projections filled with mitochondria. The regenerative cells present electron-dense cytoplasm and few organelles. The endocrine cells are characterized by electron-dense secretory granules, usually concentrated in the cytoplasm basal region.
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One of the main problems in Computer Vision and Close Range Digital Photogrammetry is 3D reconstruction. 3D reconstruction with structured light is one of the existing techniques and which still has several problems, one of them the identification or classification of the projected targets. Approaching this problem is the goal of this paper. An area based method called template matching was used for target classification. This method performs detection of area similarity by correlation, which measures the similarity between the reference and search windows, using a suitable correlation function. In this paper the modified cross covariance function was used, which presented the best results. A strategy was developed for adaptative resampling of the patterns, which solved the problem of deformation of the targets due to object surface inclination. Experiments with simulated and real data were performed in order to assess the efficiency of the proposed methodology for target detection. The results showed that the proposed classification strategy works properly, identifying 98% of targets in plane surfaces and 93% in oblique surfaces.
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Sixty-six trairão (Hoplias lacerdae) fingerlings (average weight of 2.0±0.5 g and total length of 5.8±0.2 cm), trained to accept dry rations, were allotted to six 15-L aquariums, with aeration and controlled temperature (24.0±0.5°C), in a density of 0.7 juveniles/L, aiming to evaluate the effects of darkness on fish productive performance. The treatments consisted of two photoperiods: 12 hours light: 12 hours dark (12L:12D) and 0 hour light: 24 hours dark (OL:24D), with three replicates. Fingerlings were fed ad libitum a commercial extruded diet (42% CP), twice a day. The aquariums were cleaned daily for excrement withdrawal through siphoning, exchanging 1/4 total volume. At the end of the experiment (30 days), weight gain, feed:gain ratio and survival and cannibalism rates were evaluated. The results showed that darkness did not affect the productive performance of trairão juveniles.
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The objective of this study was to evaluate the dynamic performance of an agricultural tractor utilizing distilled biodiesel (50% ethylic + 50% methylic) as a function of the proportion of biodiesel and diesel of petroleum (0 and 100%, 5 and 95%, 15 and 85%, 25 and 75%, 50 and 50%, 75 and 25% and 100 and 0%), respectively. This research was done in the area of the Department of Rural Engineering of the Paulista State University (UNESP), Jaboticabal Campus, SP, located in the latitude 21° 14′ 28″ S and longitude 48° 17′12″ W. A tractor 4 x 2 FWA was used, with a 73.6 kW (100 HP) motor and a ballast tractor. The biodiesel used was produced from spent oil from food frying. The experimental design was entirely randomized, with 7 treatments and 5 repetitions, totaling 35 observations. The results showed that the biodiesel and diesel blend significantly influenced the hourly volumetric consumption, hourly mass consumption, fuel consumption per worked area and specific fuel consumption variables. When the tractor operated with 100% of biodiesel (B100) the specific fuel consumption increased 18% on average in relation to diesel (B0).
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The work was realized at the Laboratório de Ensaio de Equipamentos de Irrigação do Departamento de Engenharia Rural da Universidade Estadual Paulista FCA- UNESP de Botucatu - SP, it aims evaluated in bench, the flow of a microsprinkler flow with dynamic nominal 43L h-1, before and after the use of gray water. In the first phase were 25 new emitters were separated and performed tests with clean water, at pressures from 50 to 300 kPa. In a second phase the emitters have been submitted 1000h operating with gray water. At the end of this time, the emitters were submitted again into conditions of initial essay, to evaluate the new costume water effect on medium flow from microsprinkler. At the end we can see that the average flow of the emitters, after use, has declined compared to the emitters discharge before use in 6,6%, the coefficient of variation after use was 5,1%, increased in proportion the coefficient of initial production was 4,3%, the R 2 fell from 0.9946 to 0.9898 and the microsprinkler continued with a high rating, according to the ABNT and ASAE.
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