Expected genetic gains with selection of provenances and progenies Pinus greggii.

Abstract. IUFRO Working Group 2.02.20

Desempenho de progênies de cipreste em Rio Negrinho-SC.

Um teste de progênies Cupressus lusitanica Miller foi implantado em Rio Negrinho, SC, em 1996, para identificar indivíduos mais promissores para seleção como matrizes de semente melhorada para plantios comerciais visando à produção de madeira e à diversificação no setor florestal brasileiro. Aos sete e dez anos, foram medidos a altura e o DAP das árvores. O teste foi instalado com sementes de 20 progênies provenientes de Popayán (Colômbia) e uma testemunha de Camanducaia, MG. O delineamento experimental foi de blocos casualizados, espaçamento de 3m x 3m com cinco plantas por parcela. Foram realizadas análises de deviance e estimados componentes de variância e parâmetros genéticos por meio do software SELEGEN-REML/BLUP (Resende, 2007). Variações significativas foram observadas entre progênies em todos os caracteres avaliados. Variações dentro de progênies ocorreram em altura e volume. As médias variaram de 11,08 a 15,31 m, 15,96 a 19,98 cm e 0,13 a 0,26 m3/arvore em altura, DAP e volume, respectivamente. A herdabilidade no sentido restrito variou de 0,27 a 0,48 em altura. Esse material apresenta variabilidade genética suficiente para ser explorada nas próximas gerações de seleção, bem como para a formação de pomares de sementes por mudas

Variação genética em progênies australianas de Grevillea robusta.

Resumo

Mechanisms of Myocardial Ischemia in Hypertrophic Cardiomyopathy : Insights From Wave Intensity Analysis and Magnetic Resonance

Background: Angina is common in hypertrophic cardiomyopathy (HCM) and is associated with abnormal myocardial perfusion. Wave intensity analysis improves the understanding of the mechanics of myocardial ischemia. Objectives: Wave intensity analysis was used to describe the mechanisms underlying perfusion abnormalities in patients with HCM. Methods: Simultaneous pressure and flow were measured in the proximal left anterior descending artery in 33 patients with HCM and 20 control patients at rest and during hyperemia, allowing calculation of wave intensity. Patients also underwent quantitative first-pass perfusion cardiac magnetic resonance to measure myocardial perfusion reserve. Results: Patients with HCM had a lower coronary flow reserve than control subjects (1.9 ± 0.8 vs. 2.7 ± 0.9; p = 0.01). Coronary hemodynamics in HCM were characterized by a very large backward compression wave during systole (38 ± 11% vs. 21 ± 6%; p < 0.001) and a proportionately smaller backward expansion wave (27% ± 8% vs. 33 ± 6%; p = 0.006) compared with control subjects. Patients with severe left ventricular outflow tract obstruction had a bisferiens pressure waveform resulting in an additional proximally originating deceleration wave during systole. The proportion of waves acting to accelerate coronary flow increased with hyperemia, and the magnitude of change was proportional to the myocardial perfusion reserve (rho = 0.53; p < 0.01). Conclusions: Coronary flow in patients with HCM is deranged. Distally, compressive deformation of intramyocardial blood vessels during systole results in an abnormally large backward compression wave, whereas proximally, severe left ventricular outflow tract obstruction is associated with an additional deceleration wave. Perfusion abnormalities in HCM are not simply a consequence of supply/demand mismatch or remodeling of the intramyocardial blood vessels; they represent a dynamic interaction with the mechanics of myocardial ischemia that may be amenable to treatment