Genetic diversity and population history of golden monkeys (Rhinopithecus roxellana)

Golden monkey (Rhinopithecus roxellana), namely the snub-nosed monkey, is a well-known endangered primate, which distributes only in the central part of mainland China. As an effort to understand the current genetic status as well as population history of this species, we collected a sample of 32 individuals from four different regions, which cover the major habitat of this species. Forty-four allozyme loci were surveyed in our study by allozyme electrophoresis, none of which was found to be polymorphic. The void of polymorphism compared with that of other nonhuman primates is surprising particularly considering that the current population size is many times larger than that of some other endangered species. Since many independent loci are surveyed in this Study, the most plausible explanation for our observation is that the population has experienced a recent bottleneck. We used a coalescent approach to explore various scenarios of population bottleneck and concluded that the most recent bottleneck could have happened within the last 15,000 years. Moreover, the proposed simulation approach could be useful to researchers who need to analyze the non- or low-polymorphism data.

Light-induced changes in diphasic nanocrystalline silicon films and solar cells

A series of diphasic nanocrystalline silicon films and solar cells was prepared using different hydrogen dilution ratios of silane by very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD). It was observed that after light soaking the open circuit voltage (V-oc) of the diphasic solar cells increased, while that of amorphous silicon solar cells decreased. Raman scattering spectroscopy was performed on the series of diphasic silicon films before and after light soaking. It was found that after light soaking the nanostruclures in the diphasic nanocrystalline silicon films were changed. Both the grain sizes and grain volume fraction reduced, while the grain boundary components increased. These results provide experimental evidence for the conjecture that the light-induced increase in V-oc of the diphasic nanocrystalline solar cells might be induced by the changes in the nanostructure of the intrinsic layer. (c) 2006 Elsevier B.V. All rights reserved.