Character and OTU stability in five taxonomic groups

The character and OTU stability of classifications based on UPGMA clustering and maximum parsimony (MP) trees were compared for 5 datasets (families of angiosperms, families of orthopteroid insects, species of the fish genusIctalurus, genera of the salamander family Salamandridae, and genera of the frog family Myobatrachidae). Stability was investigated by taking different sized random subsamples of OTUs or characters, computing UPGMA clusters and an MP tree, and then comparing the resulting trees with those based on the entire dataset. Agreement was measured by two consensus indices, that of Colless, computed from strict consensus trees, and Stinebrickner's 0.5-consensus index. Tests of character stability generally showed a monotone decrease in agreement with the standard as smaller sets of characters are considered. The relative success of the two methods depended upon the dataset. Tests of OTU stability showed a monotone decrease in agreement for UPGMA as smaller sets of OTUs are considered. But for MP, agreement decreased and then increased again on the same scale. The apparent superiority of UPGMA relative to MP with respect to OTU stability depended upon the dataset. Considerations other than stability, such as computer efficiency or accuracy, will also determine the method of choice for classifications.     

Beyond heuristics and biases: A contingency model of judgemental forecasting

The conflicting viewpoints about the quality of judgemental forecasts are examined and a model is proposed that attempts to resolve the conflict. The model sees forecasts as contingent upon the repertory of forecasting strategies that the forecaster brings to the forecasting task, the strategy that he or she selects as a function of the characteristics of the task, and the rigour with which he or she applies the strategy as a function of the motivating characteristics of the environment in which the task is encountered. The implications of differences in subjects' and experimenters' assumptions about which strategies are appropriate in experimental studies are examined, as are the implications of the differences between the motivating aspects of experimental and applied settings on both performance and on the generatizability of the results of experiments to applied judgemental forecasting.     

The effects of sodium and amiloride on the motility of the caudal epididymal spermatozoa of the rat

Summary The forward motility of the rat caudal epididymal spermatozoa has been studied in different Na⁺ concentrations. When spermatozoa were suspended in a completely Na⁺-free solution, the forward motility suffered a progressive fall and after 3 h was completely suppressed. This effect was fully reversible on resuspending the spermatozoa in a solution containing Na⁺. Amiloride caused a fall in motility and the effect was similar to that of Na⁺ removal. The inhibition by amiloride of the motility was concentration dependent and the dose response curve showed an IC₅₀-value of about 5×10^–5 M. The role of Na⁺ influx in the maintenance of sperm motility was discussed.This work was supported by the World Health Organization.The technical assistance of Mr C.M. Li and the gift of amiloride from Merck, Sharp and Dohme are gratefully acknowledged.     

A study on the Web intelligence

This paper surveys important aspects of Web Intelligence (WI). WI explores the fundamental roles as well as practical impacts of Artificial Intelligence (AI) and advanced Information Technology (IT) on the next generation of Web - related products, systens, and activities. As a direction for scientific research and devlopment,WI can be extremely beneficial for the field of Artificial Intelligence in Education (AIED). This paper covers these issues only very briefly. It focuses more on other issues in WI, such as intelligent Web services, and semantic web, and proposes how to use them as basis for tackling new and challenging research problems in AIED.     

韩国的全球化和行政改革

本文回顾了1997年经济危机后韩国政府采取的改革方案,并做出结论:与普遍的看法相反,韩国政府的大部分改革方案并不是基于新公共管理系统(NPM)的.NPM倡导的打破常规的概念是要把官僚主义者从政府内部的束缚中解放出来,然而韩国政府的改革目标却指向加强官僚政治的内部控制.另一个结论是:以NPM为导向的改革方案不适合韩国政府,因为韩国缺少成功实施NPM方案所应具备的先决条件,如基于规则的政府和充满活力的市场.本文强调了加强官僚政治外部控制机制的重要性.体制僵化、腐败、生产力低下这样的问题长期困扰韩国政府,这些问题不能通过采用NPM所建议的市场原则来解决.因此,本文的结论是:新统治理论是根除这些问题的更为行之有效的方法.     

韩国大学IT结构的发展

具有战略意义的信息系统会给一个组织带来极大的机遇,使其在执行商业计划和实现商业目标时获得极具竞争力的优势.大学信息系统始于最初的计算机应用,后来扩展到管理和教育信息系统,直至全方位的概念.通过实际分析和案例补充,当前的研究工作谨慎地选择了三所大学,主要基于其已经承担了从1995到2001年信息系统计划过程.而这三所学校可以从信息产业系统结构的三个组成部分(即信息结构、基结构和信息管理结构)进行比照.这三个系统领域涵盖了信息产业结构的发展,并影响着大学信息化的进程.作为满足当前客户需求的执行计划的一部分,市场中的一流大学通过获得教育和研究进步及管理效率化,将信息化作为获得更高竞争力的阶梯是显然的.研究分析结果显示,薄弱环节反映在信息管理结构上.由此,对于大学职员、管理者和教授而言,清楚信息系统的成功执行和维护的意义是至关重要的.我们的研究一定可以成为未来大学信息化工程的催化剂.