普可尼亚厚垣菌生物防治应用价值的室内初步评估

通过对8株普可尼亚厚垣菌（Pochonia chlamydosporium)的产厚垣孢子能力、在植物根际的定殖能力、分生孢子对土壤抑菌作用的敏感性及真菌对线虫Panagrellus redivivus的固定率等10项评价指标的测定，初步评估了这8株普可尼亚厚垣菌对线虫的生物防治潜力．结果表明366及284菌株各项指标均优于其它菌株，可以作为研制线虫生防制剂的出发菌株．此外，对普克尼亚厚垣菌的室内生防评估方法进行了分析．     

Subset threshold autoregression

We develop in this paper an efficient way to select the best subset threshold autoregressive model. The proposed method uses a stochastic search idea. Differing from most conventional approaches, our method does not require us to fix the delay or the threshold parameters in advance. By adopting the Markov chain Monte Carlo techniques, we can identify the best subset model from a very large of number of possible models, and at the same time estimate the unknown parameters. A simulation experiment shows that the method is very effective. In its application to the US unemployment rate, the stochastic search method successfully selects lag one as the time delay and five best models from more than 4000 choices. Copyright © 2003 John Wiley & Sons, Ltd.     

构筑产学研结合立体网络的研究与实践

从校内“局域网”、社会“城域网”以及全球“因特网”三个方面探讨产学研结合立体网络的构建。联系工作实际，探索校企合作建设产学研基地和网络的有效途径。     

Structure of the detoxification catalyst mercuric ion reductase from Bacillus sp. strain RC607

Several hundred million tons of toxic mercurials are dispersed in the biosphere. Microbes can detoxify organo-mercurials and mercury salts through sequential action of two enzymes, organomercury lyase and mercuric ion reductase (MerA). The latter, a homodimer with homology to the FAD-dependent disulphide oxidoreductases, catalyses the reaction NADPH + Hg(II)----NADP+ + H+ + Hg(0), one of the very rare enzymic reactions with metal substrates. Human glutathione reductase serves as a reference molecule for FAD-dependent disulphide reductases and between its primary structure and that of MerA from Tn501 (Pseudomonas), Tn21 (Shigella), p1258 (Staphylococcus) and Bacillus, 25-30% of the residues have been conserved. All MerAs have a C-terminal extension about 15 residues long but have very varied N termini. Although the enzyme from Streptomyces lividans has no addition, from Pseudomonas aeruginosa Tn501 and Bacillus sp. strain RC607 it has one and two copies respectively of a domain of 80-85 residues, highly homologous to MerP, the periplasmic component of proteins encoded by the mer operon. These domains can be proteolytically cleaved off without changing the catalytic efficiency. We report here the crystal structure of MerA from the Gram-positive bacterium Bacillus sp. strain RC607. Analysis of its complexes with nicotinamide dinucleotide substrates and the inhibitor Cd(II) reveals how limited structural changes enable an enzyme to accept as substrate what used to be a dangerous inhibitor. Knowledge of the mode of mercury ligation is a prerequisite for understanding this unique detoxification mechanism.     

扰动对天敌有多食性模型稳定性的影响

本文主要讨论了扰动对天敌具有多食性模型 x_1=x_1(r_1-a_1y), x_2=x_2(r_2-a_2y), y=y(-r_3+b_1x_1+b_2x_2)稳定性的影响。利用Liapunov函数得到了昆虫种类内部的密度制约,将促使昆虫与天敌系统进一步稳定化,进而得出同一食饵水平上的竞争是不稳定化的结论。其中后一种情况与J.M,Smith的结论完全一致。     

浅论新时期高校学生思想政治工作

新的形势既为高校学生思想政治工作提供了难得的历史机遇,也提出了更高的要求和严峻的挑战.高校学生思想政治工作要与时俱进、开拓创新,找准新的切入点.     

Web2.0环境下图书情报领域的知识管理

阐述了图书情报机构知识管理的概念和内容,介绍了Blog,RSS和Wiki在图书情报机构知识管理中的应用,并在此基础上提出了基于Web2.0环境下图书情报机构知识管理的发展策略。