On theory and methods for advanced detonation-driven hypervelocity shock tunnels

This study describes theory and methods for developing detonation-driven shock tunnels in hypervelocity test facilities. The primary concept and equations for high-enthalpy shock tunnels are presented first to demonstrate the unique advantage of shock tubes for aerodynamic ground-based testing. Then, the difficulties in simulating flight conditions in hypervelocity shock tunnels are identified, and discussed in detail to address critical issues underlying these difficulties. Theory and methods for developing detonation drivers are proposed, and relevant progress that has advanced the state of the art in large-scale hypersonic test facilities is presented with experimental verifications. Finally, tailored conditions for detonation-driven shock tunnels are described, laying a solid foundation to achieve long test duration. This interface-matching key issue encountered in developing shock tunnels has been investigated for decades, but not solved for detonation drivers in engineering applications.     

Genomic consequences of population decline in critically endangered pangolins and their demographic histories

Pangolins are among the most critically endangered animals due to heavy poaching and worldwide trafficking. However, their demographic histories and the genomic consequences of their recent population declines remain unknown. We generated high-quality de novo reference genomes for critically endangered Malayan (Manis javanica, MJ) and Chinese (M. pentadactyla, MP) pangolins and re-sequencing population genomic data from 74 MJs and 23 MPs. We recovered the population identities of illegally traded pangolins and previously unrecognized genetic populations that should be protected as evolutionarily distinct conservation units. Demographic reconstruction suggested environmental changes have resulted in a population size fluctuation of pangolins. Additionally, recent population size declines due to human activities have resulted in an increase in inbreeding and genetic load. Deleterious mutations were enriched in genes related to cancer/diseases and cholesterol homeostasis, which may have increased their susceptibility to diseases and decreased their survival potential to adapt to environmental changes and high-cholesterol diets. This comprehensive study provides not only high-quality pangolin reference genomes, but also valuable information concerning the driving factors of long-term population size fluctuations and the genomic impact of recent population size declines due to human activities, which is essential for pangolin conservation management and global action planning.     

Understanding divergent domestication traits from the whole-genome sequencing of swamp- and river-buffalo populations

Domesticated buffaloes have been integral to rice-paddy agro-ecosystems for millennia, yet relatively little is known about the buffalo genomics. Here, we sequenced and assembled reference genomes for both swamp and river buffaloes and we re-sequenced 230 individuals (132 swamp buffaloes and 98 river buffaloes) sampled from across Asia and Europe. Beyond the many actionable insights that our study revealed about the domestication, basic physiology and breeding of buffalo, we made the striking discovery that the divergent domestication traits between swamp and river buffaloes can be explained with recent selections of genes on social behavior, digestion metabolism, strengths and milk production.     

森林体验教育活动对城市公众环境负责任行为的影响

全球可持续发展和中国生态文明教育对激发公众环境意识、引导公众环境负责任行为提出了更高要求,尤其对于城市公众的影响意义重大。北京市率先引入森林体验教育理念,发挥森林生态系统文化服务功能,开展丰富多彩的森林体验教育活动。本文基于心流理论及其他文献,构建了森林体验教育活动对引导公众环境负责任行为影响的概念模型,以北京为例调查了676位参与活动的公众,运用结构方程模型方法验证了参与动机（活动前）、活动体验（活动中）对环境负责任行为（活动后）的影响机理。研究结果表明活动体验对引导公众环境负责任行为的影响是显著且正向的,并且是参与动机和环境负责任行为之间关系的完全中介变量。这一结论说明了森林体验教育活动的有效性和必要性,为进一步提升北京市活动效果和推动中国其他地区类似活动提供了理论支撑和实践参考。     

基于模糊集对分析的营销风险改进方案选择模型研究

应用模糊集对分析理论建立一个营销风险改进方案选择模型,该模型综合考虑了各方案的改进效果和改进成本,应用它所选择出的方案效果好成本小。     

出口退税政策对湖北省外向型经济发展的影响及对策分析

通过出口退税政策与湖北省出口贸易的相关性分析,探究了出口退税政策变动对湖北省外向型企业经济发展的影响,结合湖北省的实际情况,提出了应对之策。     

内部评级法与国有商业银行不良资产化解对策研究

通过分析国有商业银行不良资产现状及成因,介绍内部评级法的内容框架和我国现有五级分类贷款的局限性,说明了内部评级法是化解国有商业银行不良资产的根本出路,指出我国目前实施IRB法存在的问题及IRB法在我国实施的对策选择。     

Manpower needs in rural school psychology

The majority of unserved and underserved handicapped children live in rural America (Sher, 1978). One obstacle to serving these children is a lack of qualified staff (Helge, 1981). The turnover rates for rural and urban school psychologists in Virginia were determined for the years 1977–78 through 1979–80: the rate for rurai school psychologists is four times the rate for urban school psychologists (p<.001). Rural school psychologists who terminated employment and rural school psychologists who remained were surveyed on selected background variables in 1981. School psychologists who remained were much more likely than those who left to have been raised in a nonurban community. Implications for training programs are discussed.