The Ashbya gossypii genome as a tool for mapping the ancient Saccharomyces cerevisiae genome

We have sequenced and annotated the genome of the filamentous ascomycete Ashbya gossypii. With a size of only 9.2 megabases, encoding 4718 protein-coding genes, it is the smallest genome of a free-living eukaryote yet characterized. More than 90% of A. gossypii genes show both homology and a particular pattern of synteny with Saccharomyces cerevisiae. Analysis of this pattern revealed 300 inversions and translocations that have occurred since divergence of these two species. It also provided compelling evidence that the evolution of S. cerevisiae included a whole genome duplication or fusion of two related species and showed, through inferred ancient gene orders, which of the duplicated genes lost one copy and which retained both copies.     

基于AEZ模型的我国水稻产量潜力的农作制区划分析

本文根据联合国粮农组织(FAO)和国际应用系统分析研究所(IIASA)基于中国1961~1997年的统计资料(经多方校正)共同开发的AEZ模型,运用G IS平台计算了中国41个农作制亚区的水稻生产潜力,并指出了单产最高潜力分布区域。研究结果表明:我国水稻的最高产量潜力大约将是目前产量的2倍。这对我国水稻高产育种及栽培具有重要参考意义。     

Preferential distribution of fish larvae in the California Current System: Time,space, and temperature

The preferential larval distributions of 22 fish species in the California Current System were identified in their temporal, spatial, and thermal domains using single parameter quotient analysis. This analysis allowed the characterization of their reproductive habitats based on ranges of preference, tolerance, and avoidance. In the temporal domain, the species’ preference intervals were wider than those previously reported, and all species showed preferences during two or more seasons of the year. In the spatial domain, the preferential distributions of the species were also wider, and some of them had different preferred zones from those described in previous works. Because one group of species was preferably distributed in coastal zones, and the other group was preferably distributed in oceanic zones, the biological production mechanisms sustaining these groups differ, namely, coastal upwelling and geostrophic fluxes of subarctic origin, respectively. In the thermal domain, the larval distribution preferences of 20 of 22 species have been determined for the first time, providing important information on their thermal tolerance window during the larval stage, a window that changes in width throughout each of the ontogenetic stages of fish. The distribution in each domain suggests association patterns between species, but additional studies are necessary to validate these patterns.     

Integrating fishing and conservation in a risk framework: A stochastic population model to guide the proactive management of a threatened freshwater crayfish

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Generating information for aquaculture development: The art and science of economic policy modelling

Abstract

The rapid growth of aquaculture and concerns about economic and ecological ‘sustainability’ have focused attention on industry externalities. Developing institutions which ‘sustain’ aquaculture will require skills in the ‘art and science’ of public policy modelling. Analysis of existing approaches demonstrates that no single modelling paradigm is ‘best’ for all aquaculture policy situations. Modelling approaches other than cost‐benefit including multiobjective analysis may be more appropriate if the objective of the modeller is to improve the effectiveness of the policy process itself. A review of the relatively small but growing literature on aquaculture policy models reveals a wide range of issues and approaches. In general, economic models have focused on the single objective of maximizing efficiency; in contrast, models used in actual aquacultural policy and planning focus on controlling environmental pollution. The findings suggest that economic models have not yet played a significant role in aquacultural policy development. This raises concerns that myopic views of ‘sustainability’ will result in institutions which do not promote socially efficient aquacultural industry growth.