University of Winnipeg

About: University of Winnipeg is a education organization based out in Winnipeg, Manitoba, Canada. It is known for research contribution in the topics: Population & Context (language use). The organization has 3235 authors who have published 6413 publications receiving 150564 citations. The organization is also known as: U of W.

Inoculation of bats with European Geomyces destructans supports the novel pathogen hypothesis for the origin of white-nose syndrome

Abstract: White-nose syndrome (WNS) is an emerging disease of hibernating bats associated with cutaneous infection by the fungus Geomyces destructans (Gd), and responsible for devastating declines of bat populations in eastern North America. Affected bats appear emaciated and one hypothesis is that they spend too much time out of torpor during hibernation, depleting vital fat reserves required to survive the winter. The fungus has also been found at low levels on bats throughout Europe but without mass mortality. This finding suggests that Gd is either native to both continents but has been rendered more pathogenic in North America by mutation or environmental change, or that it recently arrived in North America as an invader from Europe. Thus, a causal link between Gd and mortality has not been established and the reason for its high pathogenicity in North America is unknown. Here we show that experimental inoculation with either North American or European isolates of Gd causes WNS and mortality in the North American bat, Myotis lucifugus. In contrast to control bats, individuals inoculated with either isolate of Gd developed cutaneous infections diagnostic of WNS, exhibited a progressive increase in the frequency of arousals from torpor during hibernation, and were emaciated after 3–4 mo. Our results demonstrate that altered torpor-arousal cycles underlie mortality from WNS and provide direct evidence that Gd is a novel pathogen to North America from Europe.

Shadowed sets: representing and processing fuzzy sets

Abstract: This study introduces a new concept of shadowed sets that can be regarded as a certain operational framework simplifying processing carried out with the aid of fuzzy sets and enhancing interpretation of results obtained therein. Some conceptual links between this idea and some others known in the literature are established. In particular, it is demonstrated how fuzzy sets can induce shadowed sets. Subsequently, shadowed sets reveal interesting conceptual and algorithmic relationships existing between rough sets and fuzzy sets. Detailed computational aspects of shadowed sets are discussed. Several illustrative examples are provided.

Evolution in the Fast Lane: Rapidly Evolving Sex-Related Genes in Drosophila

Abstract: A large portion of the annotated genes in Drosophila melanogaster show sex-biased expression, indicating that sex and reproduction-related genes (SRR genes) represent an appreciable component of the genome. Previous studies, in which subsets of genes were compared among few Drosophila species, have found that SRR genes exhibit unusual evolutionary patterns. Here, we have used the newly released genome sequences from 12 Drosophila species, coupled to a larger set of SRR genes, to comprehensively test the generality of these patterns. Among 2505 SRR genes examined, including ESTs with biased expression in reproductive tissues and genes characterized as involved in gametogenesis, we find that a relatively high proportion of SRR genes have experienced accelerated divergence throughout the genus Drosophila. Several testis-specific genes, male seminal fluid proteins (SFPs), and spermatogenesis genes show lineage-specific bursts of accelerated evolution and positive selection. SFP genes also show evidence of lineage-specific gene loss and/or gain. These results bring us closer to understanding the details of the evolutionary dynamics of SRR genes with respect to species divergence.

Helical Coordination Polymers with Large Chiral Cavities

Abstract: A quarter of the unit cell volume of [{Ni(4,4'-dipy)(3-nitrobenzoate)2 (MeOH)2 }n ], which crystallizes in the form of helices, is occupied by large chiral cavities (400-500 A3 ). The cavities are capable of encapsulating not only single molecules, but also face-to-face dimers of nitrobenzene (see stick model). 4,4'-dipy=4,4'-bipyridine.