495 resultados para moscas-brancas


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At head of title: Cuadros y escenas de la revolucion mexicana.

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Esta pesquisa fundamenta-se em uma perspectiva psicossocial da Teoria das Representações Sociais, sistematizada por Serge Moscovici, Denise Jodelet e demais colaboradores, com o objetivo de analisar como revistas informativas semanais (Veja e CartaCapital) representam questões relacionadas ao professor. A temática, do ponto de vista teórico, justifica-se em face do papel fundamental da mídia na sociedade contemporânea como difusora e produtora de informações. Foram levantados produtos jornalísticos publicados, durante um ano, na maior e mais importante revista semanal de informação do País (Veja) e em CartaCapital sobre a temática professor e suas variantes. O único critério para seleção dos textos foi que versassem sobre o professor brasileiro, independentemente do grau de ensino, sendo incluídas reportagens, entrevistas e/ou artigos opinativos. Esta investigação abarca ainda como recurso teórico-metodológico, o conceito de representações midiáticas conforme elaborado por Sary Calonge. Foram analisados 79 produtos jornalísticos entre janeiro de 2012 e janeiro de 2013 que indicaram que o professor é praticamente um ser invisível nas pautas de reportagens e artigos desses veículos de comunicação. Professor para falar sobre educação, só se for da área econômica. Nas poucas vezes em que é mencionado ou até aparece com algum destaque, percebe-se o uso de estereótipos e clichês, o que aponta a existência de um discurso naturalizado na mídia que ora o aponta como vilão, ora o trata como vítima das circunstâncias que permeiam a situação atual da Educação no Brasil.

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The fruit fly Ceratitis capitata is considered the most destructive pest of the world fruitculture. Many pest management practices, mainly based on agrochemicals, have been developed to allow the world-wide commerce of fruit. Solutions to decrease the use of synthetic insecticides in agriculture are based on the development of new target-specific compounds which cause less damage to the environment, especially vegetal proteins with insecticidal effects. The aim of this work was to evaluate the deleterious effect of a purified vicilin of E. velutina (EvV) seeds to C. capitata larvae and adult insects and to investigate the mechanisms involved in these effects. EvV was purified, characterized and its deleterious effect was tested in bioassay systems. EvV mechanism of action was determined by immunodetection techniques and fluorescence localization in chitin structures that are present in C. capitata digestory system. EvV is a glycoprotein with affinity to chitin. Its molecular weight, of 216,57 kDa, was determined by gel filtration chromatography in FPLC system. Using SDS-PAGE, it was possible to observe EvV dissociation in two main subunits of 54,8 and 50,8 kDa. When it was submitted to eletrophoresis in native conditions, EvV presented only one band of acid characteristic. The WD50 and LD50 values found in the bioassays were 0,13% and 0,14% (w/w), respectively for the larvae. EvV deleterious effects were related to the binding to chitin structures presented in peritrophic membrane and gut epithelial cells, associated with its low digestibility in C. capitata digestive tract. The results described herein are the first demonstration of the larvicidal effects of plant protein on C. capitata larvae. EvV may be part of the pest management programs, in the toxic bait composition, or an alternative in plant improvement program

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Chitin-binding vicilins from legume seeds (Erythrina velutina. Canavalia ensiformes and Phaseolus vulgares) were isolated by ammonium sulfate followed by affinity chromatography on a chitin column. Effect of these vicilins on female adults of Ceratitis capitata was examined by bioassay and in a semi-field assay model. Mechanism of action of the vicilins was determined by in vivo digestibility and chitin affinity. Among the tested vicilins, E. velutina when added to diet caused strong effect on mortality at 10% dose. This insecticidal property was tested in a semi-field assay which showed the same effect observed in laboratory conditions, where doses of 10% and 15% were lethal to female adults of C. capitata. These deleterious effects were not only associated to the binding to chitin structures present in peritrophic membrane, but principally to its low digestibility in the C. capitata digestive tract. This fact was confirmed because chiting binding proteins as WGA and the other tested vicilins were not toxic to female adults of C. capitata due susceptibility of these proteins to digestive enzymes of the insects. By other side EvV was more resistant to digestive enzymes, causing deleterious effects on female adults of C. capitata. These results showed that EvV may be part of the pest management programs or an alternative in plant improvement program in the population control of this fruticulture pest

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Buscou-se avaliar a distribuição espacial da resistência aos pesticidas piretróides nas populações de moscas-dos-chifres em dois importantes polos pecuários de Rondônia: a microrregião de Porto Velho, com grande efetivo de bovinos de corte e a microrregião de Ji-Paraná, onde encontra-se estabelecida a principal bacia leiteira estadual.