1,335 research outputs found
Sistema de gerenciamento dos Bancos Ativos de Germoplasma da Embrapa Trigo.
bitstream/CNPT-2010/40598/1/p-co233.pd
Resistance of Echinochloa crusgalli var. mitis to imazapyr+imazapic herbicide and alternative control in irrigated rice
A introdução do sistema Clearfield® de produção de arroz irrigado proporcionou estratégia eficaz no controle seletivo de plantas daninhas. No entanto, a pressão de seleção causada pelo uso contínuo de herbicidas como imazapyr+imazapic, pertencente ao grupo químico das imidazolinonas, sem o adequado manejo integrado de plantas daninhas, tem favorecido a seleção de acessos de plantas daninhas resistentes. Os objetivos deste trabalho foram confirmar a resistência aos inibidores da ALS em acessos de E. crusgalli var.mitis coletados em lavouras do RS e avaliar o controle desses acessos com herbicidas alternativos registrados para o controle da espécie daninha na cultura do arroz irrigado. Foram conduzidos três experimentos em casa de vegetação, utilizando-se sementes provenientes de plantas que sobreviveram à aplicação do herbicida imazapyr+imazapic, coletadas em lavouras com escapes suspeitos de resistência, em regiões produtoras de arroz irrigado. Para o estudo de curva de dose-resposta, foram selecionados três biótipos resistentes (ECH1 - Pelotas/RS, ECH27 - Arroio Grande/RS e ECH38 - Rio Grande/RS) e dois suscetíveis (ECH14 - Pelotas/RS e ECH44 - Rio Grande/RS) (fator A) e 11 doses do herbicida imazapyr+imazapic (fator B). Os resultados indicam que os acessos resistentes de capim-arroz apresentam elevado fator de resistência ao imazapyr+imazapic. Os herbicidas inibidores da ALS como imazethapyr+imazapic, bispyribac-sodium e penoxsulam, não controlaram os acessos resistentes também. O manejo integrado de plantas daninhas deveria ser adotado e mecanismos de ação alternativos como inibidores da ACCAse (cyhalofop-butyl, profoxydim e clethodim) e da EPSPS (glyphosate) ainda são eficientes em controlar acessos de capim-arroz resistentes a ALS
Metabolic evidence of viable myocardium in regions with reduced wall thickness and absent wall thickening in patients with chronic ischemic left ventricular dysfunction
AbstractReduced end-diastolic wall thickness with absent systolic wall thickening has been reported to represent nonviable myocardium in patients with chronic coronary artery disease. To assess whether reduced regional end-diastolic wall thickness and absent wall thickening accurately identify nonviable myocardium, 25 patients with ischemic left ventricular dysfunction (ejection fraction at rest 27 ± 10%) underwent positron emission tomography with oxygen-15-labeled water and 18fluorodeoxyglucose to assess metabolic activity and spin-echo gated nuclear magnetic resonance imaging to measure regional end-diastolic wall thickness and wall thickening. The presence of metabolic activity was defined as 18fluorodeoxyglucose uptake (corrected for partial volume) >50% of that in normal regions.Of 355 myocardial regions evaluated, 266 were hypokinetic or normokinetic at rest and 89 were akinetic (that is, absent wall thickening). 18Fluorodeoxglucose uptake was observed in 97% of the hypokinetic and normokinetic regions and in 74% of the akinetic regions. End-diastolic wall thickness was greater in akinetic regions with than in those without 18fluorodeoxyglucose uptake (11 ± 4 vs. 7 ± 3 nun, p < 0.01). The highest values for sensitivity and specificity of end-diastolic wall thickness in predicting the absence of metabolic activity in akinetic regions were 74% and 79%, respectively, and corresponded to an end-diastolic threshold of 8 mm. However, the positive predictive accuracy was only 55% and did not improve for other end-diastolic wall thickness values. In all myocardial regions, there was only a weak correlation between 18fluorodeoxyglucose activity and either end-diastolic wall thickness (r = 0.17) or wall thickening (r = 0.32).Thus, metabolic activity is present in many regions with reduced end-diastolic wall thickness and absent wall thickening. These data indicate that assessment of regional anatomy and function may be inaccurate in distinguishing asynergic but viable myocardium from nonviable myocardium
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