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. Pedigree and mating system analyses in a western larch (Larix occidentalis Nutt.) experimental population. Annals of Forest Science, Springer Verlag/EDP Sciences, 2008, 65 (7), pp.1. Ann. For. Sci. 65 (2008) Abstract•The mating pattern and gene flow in a western larch (Larix occidentalis Nutt.) experimental population was studied with the aid of microsatellite markers and a combination of paternity-mating system analysis. The commonly difficult to assess, male gametic contribution was determined with 95% confidence and its impact on genetic gain and diversity was determined.• Male fertility success rate ranged between 0 and 11%. Male reproductive output parental imbalance was observed with 50% of the pollen being produced by the top 5% of males while the lower 39% males only produced 10% of the pollen.• A significant difference was observed between male effective population size (genetic diversity) estimates from paternity assignment compared to those based on population's census number (21 vs. 41); however, this difference did not affect estimates of genetic gain.• A total of 221 full-fib families were identified (sample size range: 1-8) and were nested among the studied 14 seed-donors.• A combination of paternity-mating system analysis is recommended to provide a better insight into seed orchards' mating dynamics. While pollen flow tends to inflate mating system's outcrossing rate, the paternity analysis effectively determined the rate and magnitude of contamination across receptive females. • Le taux de succès reproductif mâle était compris entre 0 et 11 %. Un déséquilibre dans la contribution des parents mâles a été observé avec la production de 50 % du pollen par 5 % des pères alors que 39 % d'entre eux ne contribuaient que pour seulement 10 % du pollen. Mots-clés• Une différence significative a été observée entre la taille efficace de la population mâle (diversité génétique) estimée par la recherche de paternité et celle basée sur les effectifs recensés de la population (21 vs. 41) ; cependant, cette différence n'affecte pas l'estimation du gain génétique.• 221 familles de plein-frères ont été identifiées (effectifs entre 1 et 8), regroupées parmi les 14 arbresmères étudiés.• La combinaison d'une analyse de paternité et du système de reproduction est recommandée pour étudier de manière approfondie la dynamique de croisement en vergers à graines. Tandis que les flux de pollen tendent à augmenter le taux d'inter-croisements, l'analyse de paternité détermine de manière effective le taux et l'amplitude de contamination des arbres-mères.

This study investigated downscatter effects in cardiac single-photon emission tomographic studies with simultaneous thallium-201/technetium-99m acquisition, and evaluated a previously proposed subtraction technique for downscatter compensation. Ten studies were carried out with different defect sizes and locations and varying activity distributions using four energy windows: 70+/-10% keV, 140+/-10% keV, 100+/-10% KeV, and 103+/-16% keV. The subtraction technique used the 100- or 103-keV data to remove scattered 99mTc counts from the 70-keV data. The size and contrast of infarcts in the dual-isotope 70-keV image were artificially decreased compared to those in the 140-keV image, caused by scattered 99mTc counts that were comparable to the primary 201Tl counts in the 70-keV window. The subtraction technique produced larger defects and more heterogeneous activity in the myocardial wall in dual-isotope 70-keV images compared to the corresponding 201Tl-only images. These artifacts were caused by the markedly different spatial distributions of scattered 99mTc counts in the 100-keV (or 103-keV) window as compared with the 70-keV window. It is concluded that scattered 99mTc photons may cause overestimation of ischemia and myocardial viability in simultaneous dual-isotope patient studies. The proposed subtraction technique was inaccurate and produced image artifacts. Adequate downscatter compensation methods must be developed before applying simultaneous 201Tl/99mTc acquisition in clinical practice.

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