467 resultados para DDT (Inseticida)


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Mode of access: Internet.

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"September 1978."

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Bibliography: p. 26-27.

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Mode of access: Internet.

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Typewritten.

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"Interim report no. 0-100 (NRC Insect control committee Report no. 100). A report to the Committee on medical research on work done under a transfer of funds, recommended by this committee, from the Office of scientific research and development to the Bureau of entomology and plant quarantine."--Foot-note, p. 1.

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5. Acknowledgements This research was supported by grants from the National Natural Science Foundation of China (Nos. 31172438 and U1205123), the Natural Science Foundation of Fujian Province (No. 2012J06008 and 201311180002) and the projects-sponsored by SRF. TW received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.

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A large eddy simulation is performed to study the deflagration to detonation transition phenomenon in an obstructed channel containing premixed stoichiometric hydrogen–air mixture. Two-dimensional filtered reactive Navier–Stokes equations are solved utilizing the artificially thickened flame approach (ATF) for modeling sub-grid scale combustion. To include the effect of induction time, a 27-step detailed mechanism is utilized along with an in situ adaptive tabulation (ISAT) method to reduce the computational cost due to the detailed chemistry. The results show that in the slow flame propagation regime, the flame–vortex interaction and the resulting flame folding and wrinkling are the main mechanisms for the increase of the flame surface and consequently acceleration of the flame. Furthermore, at high speed, the major mechanisms responsible for flame propagation are repeated reflected shock–flame interactions and the resulting baroclinic vorticity. These interactions intensify the rate of heat release and maintain the turbulence and flame speed at high level. During the flame acceleration, it is seen that the turbulent flame enters the ‘thickened reaction zones’ regime. Therefore, it is necessary to utilize the chemistry based combustion model with detailed chemical kinetics to properly capture the salient features of the fast deflagration propagation.

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Methomyl (Lannate®) is an insecticide from the carbamate group, frequently used in pest control in various types of crops. This compound works inhibiting the activity of the enzyme acetylcholinesterase. The use of physicochemical and ecotoxicological analysis is the most efficient strategy for the correct characterization and control of residues of metomil. The main objectives of this study were to evaluate the acute toxicity of methomyl in 96 hours of exposure and, through a sublethal assay of 5 hours, to assess its effect on the activity of acetylcholinesterase present in brain and squeletic dorsal muscle of the Danio rerio fish. The results showed that the LC50-96 found to D. rerio was 3.4 mg/L and it was found through the average of four definitive tests. In vitro assays were used to test the inhibitory action of methomyl directly over soluble AChE, extracted from the squeletic dorsal muscle, with maximum inhibition of 68.57% to the insecticide concentrations of 0.2 mg/L. In sublethal tests with D. rerio, inhibitory effect of methomyl was found over the soluble form of AChE in the squeletic dorsal muscle, both in one and five hours of fish exposure to the insecticide. In both period, the average values of inhibition were around 61%. In the same condition, no significant inhibitory effect of methomyl soluble and membrane AChE of the D. rerio was observed in the 0.42, 0.85, 1.70 and 2.50 mg/L concentrations and in both times of fish exposure

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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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Esta pesquisa estudou a ação inseticida de extrato alcoólico de alho (Allium sativum L.) e pimenta-do-reino (Piper nigrum L.), já utilizados no controle de pragas em sistemas agroflorestais no nordeste paraense, contra larvas de 4º instar de Tenebrio molitor (Col., Tenebrionidae) em laboratório. Os experimentos foram desenvolvidos no Laboratório de Entomologia da Embrapa Amazônia Oriental, em Belém, Pará. Os extratos alcoólicos de A. sativum e P. nigrum foram obtidos de 50g dos produtos vegetais, colocados em repouso em 200 mL de álcool etílico hidratado (92,8º INPM) por 5 dias. As formulações à base de 50 mL de extrato alcoólico para cada extrato isoladamente e 25 mL de ambos na mistura, com 25mL de sabão líquido cada, foram aplicadas nas concentrações de 1% e 10%, além de um tratamento testemunha com água destilada, em um delineamento experimental inteiramente casualizado, com 20 repetições. Os insetos foram expostos ao tratamento por aplicação tópica com auxílio de micropipetas com pressão e precisão de 0,2 mL e mantidos em placas de Petri com discos de papel de filtro (9,0 cm Ø), providas de pedaços de chuchu para alimentação e armazenadas em câmaras climatizadas, tipo B.O.D, à temperatura de 27 ± 2oC, umidade relativa de 70 ± 5% e fotofase de 12 horas. A mortalidade foi avaliada por 5 dias após a exposição dos mesmos aos tratamentos. Extratos alcoólicos de A. sativum e P. nigrum apresentaram ação inseticida contra larvas de T. molitor, com taxa de mortalidade variando de 60% (1º dia) a 80% (5º dia) na maior dosagem de resposta biológica (10%) do experimento