997 resultados para extrinsic resistance


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Espécies de artrópodos entomófagos foram coletadas e identificadas nos genótipos sorgo AF-28, IAC-83/75-5-1-6, TX-2536, BR-300, IPA-201 e SAR, no Município de Selvíria, MS. Foram conduzidos três experimentos em campo, com os genótipos sendo semeados em 03/1988, 10/1988 e 02/1989, respectivamente. Para contagem dos artrópodos entomófagos, no início do florescimento foram marcadas 560 panículas por genótipo. Após esse momento, diariamente e durante 14 dias seguidos, foram coletadas 40 panículas por genótipo (10 por parcela). Nas coletas foram utilizados sacos plásticos com 10 litros de capacidade para envolver as panículas e capturar os artrópodos presentes. As panículas coletadas foram levadas para o Laboratório de Entomologia da Faculdade de Engenharia/UNESP, Campus de Ilha Solteira, SP, para separação, contagem e identificação dos artrópodos. Nas panículas provenientes da semeadura da seca coletou-se, em média, maior número de artrópodos entomófagos em relação à semeadura das águas. Dos artrópodos entomófagos coletados, as aranhas apresentaram maior número de espécies e, desses, a tecelã Alpaida veniliae (Keys.), a aranha corredora noturna Cheiracanthium inclusum (Blackwall), e a caçadora de emboscada, Misumenops pallidus (Keys.), foram as mais abundantes. O genótipo de sorgo IPA-201 comportou-se como o mais atrativo ao percevejo Orius sp. e à tesourinha Doru lineare (Eschs.), enquanto que o IAC-83/75-5-1-6 foi medianamente atrativo a D. lineare. As aranhas foram coletadas em maior número nos genótipos BR-300 e SART.

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Verificou-se a influência de duas variedades de cana-de-açúcar (Saccharum spp.), incorparados em dieta artificial, na forma de colmos triturados, no desenvolvimento de Diatraea saccharalis (Fabr.) e no parasitismo de Cotesia flavipes (Cam.). A variedade SP71-1081 foi menos adequada ao desenvolvimento de D. saccharalis comparada à SP71-3146, aumentando os períodos larval e pupal (dias) e, diminuindo o peso larval; não houve diferenças para as viabilidades larval e pupal e peso de pupa. Lagartas oriundas das dietas artificiais e lagartas alojadas no interior dos toletes das variedades de cana, foram igualmente parasitadas por C. flavipes. Lagartas criadas em dieta artificial contendo colmos triturados das variedades testadas, promoveram desenvolvimento semelhante de C. flavipes. A percentagem de parasitismo foi semelhante nas larvas criadas em dietas artificiais contendo colmos das variedades SP 71 - 1081 (84,0%) e SP 71-3146 (81,3%).

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Pós-graduação em Agronomia (Produção Vegetal) - FCAV

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By using techniques of rapid quenching from the melt, metastable phases have been obtained in ternary alloys which contain tellurium as a major component and two of the three noble metals (Cu, Ag, Au) as minor components. The metastable phases found in this investigation are either simple cubic or amorphous. The formation of the simple cubic phase is discussed. The electrical resistance and the thermoelectric power of the simple cubic alloy (Au30Te70) have been measured and interpreted in terms of atomic bondings. The semiconducting properties of a metastable amorphous alloy (Au5Cu25Te70) have been measured. The experimental results are discussed in connection with a theoretical consideration of the validity of band theory in an amorphous solid. The existence of extrinsic conduction in an amorphous semiconductor is suggested by the result of electrical resistance and thermoelectric power measurements.

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In this paper, the analogue performance of a 65 nm node double gate Sol (DGSOI) is qualitatively investigated using MixedMode simulation. The intrinsic resistance of the device is optimised by evaluating the impact of the source/drain engineering using variation of spacers and doping profile on the RF key figures of merit such as f(T), and f(MAX). It is evident that longer spacers, which approach the length of the gate offer better RF performance irrespective of the profile as long as the doping gradient at the gate edge is <7 nm/decade. Analytical expressions, which reflect the dependence of f(T), and fMAX on extrinsic source, drain and gate resistances R-S, R-D and R-G have been derived. While R-D and R-S have equal effect on f(T), R-D appears to be more influential than R-S in reducing f(MAX). The sensitivity of f(MAX) to R-S and R-D. has been shown to be greater than to R-G. (c) 2006 Elsevier Ltd. All rights reserved.

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An analytical approach for CMOS parameter extraction which includes the effect of parasitic resistance is presented. The method is based on small-signal equivalent circuit valid in all region of operation to uniquely extract extrinsic resistances, which can be used to extend the industry standard BSIM3v3 MOSFET model for radio frequency applications. The verification of the model was carried out through frequency domain measurements of S-parameters and direct time domain measurement at 2.4 GHz in a large signal non-linear mode of operation. (C) 2003 Elsevier Ltd. All rights reserved.

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The behaviour of short fatigue cracks is shown to be relevant only to a limited number of engineering situations. Within these situations, further restrictions on the extent to which metallurgical control can be exerted to improve fatigue crack growth behaviour are identified. The degree of control remaining is discussed in terms of two separate regimes which are described as intrinsic and extrinsic crack growth resistance. These separate effects are highlighted by comparisons both within and between a wide range of alloy systems. The implications of such an analysis are discussed in terms of aerospace applications.

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Resistance to radiotherapy due to insufficient cancer cell death is a significant cause of treatment failure in non-small cell lung cancer (NSCLC). The endogenous caspase-8 inhibitor, FLIP, is a critical regulator of cell death that is frequently overexpressed in NSCLC and is an established inhibitor of apoptotic cell death induced via the extrinsic death receptor pathway. Apoptosis induced by ionizing radiation (IR) has been considered to be mediated predominantly via the intrinsic apoptotic pathway; however, we found that IR-induced apoptosis was significantly attenuated in NSCLC cells when caspase-8 was depleted using RNA interference (RNAi), suggesting involvement of the extrinsic apoptosis pathway. Moreover, overexpression of wild-type FLIP, but not a mutant form that cannot bind the critical death receptor adaptor protein FADD, also attenuated IR-induced apoptosis, confirming the importance of the extrinsic apoptotic pathway as a determinant of response to IR in NSCLC. Importantly, when FLIP protein levels were down-regulated by RNAi, IR-induced cell death was significantly enhanced. The clinically relevant histone deacetylase (HDAC) inhibitors vorinostat and entinostat were subsequently found to sensitize a subset of NSCLC cell lines to IR in a manner that was dependent on their ability to suppress FLIP expression and promote activation of caspase-8. Entinostat also enhanced the anti-tumor activity of IR in vivo. Therefore, FLIP down-regulation induced by HDAC inhibitors is a potential clinical strategy to radio-sensitize NSCLC and thereby improve response to radiotherapy. Overall, this study provides the first evidence that pharmacological inhibition of FLIP may improve response of NCSLC to IR.

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A new method for estimating the time to colonization of Methicillin-resistant Staphylococcus Aureus (MRSA) patients is developed in this paper. The time to colonization of MRSA is modelled using a Bayesian smoothing approach for the hazard function. There are two prior models discussed in this paper: the first difference prior and the second difference prior. The second difference prior model gives smoother estimates of the hazard functions and, when applied to data from an intensive care unit (ICU), clearly shows increasing hazard up to day 13, then a decreasing hazard. The results clearly demonstrate that the hazard is not constant and provide a useful quantification of the effect of length of stay on the risk of MRSA colonization which provides useful insight.