小心投资美国

作为美国驻华大使,骆家辉比他的前任们获得了更多的关注,＂朴素＂与＂作秀＂之争从媒体蔓延到网络。当人们还在津津乐道双肩包和经济舱的时候,骆家辉却将矛头指向中国的商业环境,＂呼吁＂中国政府停止对金融服务业及外商投资＂广泛的政府干预＂。     

Government Incentive Contracts with Private Enterprise: Some Lessons from the Channel Tunnel

Some of the dangers of the sub-optimisation which may arise when governments and private companies enter into joint ventures are illustrated in this study of the financial arrangements for construction and operation of the Channel tunnel (the project abandoned in 1975). The governments wanted the tunnel to be operated as a commercial (profit-motivated) venture, but gave the private company partners financial incentives to adopt policies in conflict with this target. The paper analyses this conflict and suggests a form of contract which retains desirable incentives but avoids the conflict of interest.     

美国微积分教学改革的一些动向

本文介绍美国大专院校微积分教学改革的一些新动向,重点是利用计算机这一当代科技成果对传统微积分教学进行改革的情况。     

拟阵中独立集个数的几个不等式

本文利用已建立的拟阵代数结构和面环的 Ｈｉｌｂｅｒｔ函数,给出了拟阵中独立集个数的几个不等式．     

Implementation of the Standards: Lessons from a Systemic Initiative

Data collected as a part of Ohio's Systemic Initiative suggest that some existing attitudes and practices of principals and teachers may provide a strong foundation for National Science Education Standards implementation. However, some data suggest that reformers have a long way to go before the Standards are fully understood and supported both by teachers and principals.     

Science Teacher Supply in the United States

The purpose of this study was to describe the supply and potential shortages of science teachers in the United States. Ninety-six percent of the State Science Consultants of the 50 State Boards of Education responded to a 1992 survey to assess the supply of science teachers. This survey was modeled after Howe and Gerlovich's 1982 study to provide an assessment of changes in science teacher supply over the last 10 years. Although there were improvements in the supply of science teachers, shortages were reported in all science subjects and were particularly critical in physics, chemistry, and earth science. In addition to providing a needed update on science teacher supply, this study analyzed 45 previous studies of science teacher supply and found convincing evidence to support the hypothesis that there is a persistent but fluctuating long term shortage of science teachers. This shortage is attributed to competition with business and industry. To alleviate critical shortages of science teachers, it is recommended that salaries be raised to be more competitive with industry and a national database be established to facilitate monitoring the supply of science teachers.     

An analysis of context-based similarity tasks in textbooks from Brazil and the United States

Three textbooks from Brazil and three textbooks from the United States were analysed with a focus on similarity and context-based tasks. Students’ opportunities to learn similarity were examined by considering whether students were provided context-based tasks of high cognitive demand and whether those tasks included missing or superfluous information. Although books in the United States included more tasks, the proportion of tasks focused on similarity were about the same. Context-based similarity tasks accounted for 9%–29% of the similarity tasks, and many of these contextual tasks were of low cognitive demand. In addition, the types of contexts that were included in the textbooks were critiqued and examples provided.     

Broad Field Science Endorsements in the United States

Data on broad field science endorsements were collected from the State Science Supervisors in the fifty states. The response rate was 96%. Sixty-one percent of the responding states have one or more broad field science endorsements. The status of broad field science endorsements has changed significantly since Blank and Espenshade's 1988 study. This study reveals tremendous diversity in the grade levels and subjects covered by broad field science endorsements, and the names for these endorsements.     

Nonlinear Approximation from Dictionaries: Some Open Problems: Research Problems 2000-3

No abstract. March 31, 2000. Date accepted: March 31, 2000.     

Preparing primary teachers in the United States: balancing selection and preparation

The recent movement in the United States toward common (national) mathematics standards brings to the fore issues of implementation which includes how teachers are prepared to teach. The Teacher Education and Development Study in Mathematics (TEDS-M) provide an international context for an in depth analysis of the US primary future teachers’ TEDS-M results. The US education system is decentralized with many aspects controlled by the states and many other aspects controlled by over 16,000 local school districts. Consequently, there is great variation in what secondary mathematics individuals have had before entering teacher preparation. In addition, as certification is a state regulation, teacher preparation programs also differ in what is provided to prospective teachers. Analyses reveal significant relationship between both of these to the mathematics content knowledge and mathematics pedagogical content knowledge of US future primary teachers. A two-stage hierarchical model is used to explore the relative contribution of these two factors.     

Spatial patterns of mortality in the United States: A spatial filtering approach

Within the field of spatial analysis, filtering has emerged as a powerful modelling technique to retrieve systematic patterns of geographical variation. In this work, spatial filtering is introduced in the context of modelling mortality for the first time in actuarial literature. Specifically, the objective of this research is to identify patterns in the spatial distribution of mortality rates for the sixty-five and older age group at the county level for the contiguous United States. The analysis carried out pertains to the spatial autocorrelation of these rates over time. The spatial filtering methodology is applied to uncover latent spatial patterns. Furthermore, the analysis reveals the extent to which these spatial patterns remained consistent across the years in the study. Results show the existence of spatial dependencies leading to an accompanying spatial filter. Thus, incorporating spatial filters as an exploratory tool in spatial analysis proves of considerable use when it comes to enriching traditional mortality models.     

Interdisciplinary activities in mathematics and science in the United States

This paper outlines the need for interdisciplinary efforts in mathematics and science at university level in the US. It summarizes the different types of activities currently taking place. They are spread along a spectrum from Minimal coordination to complete integration; each having different advantages and disadvantages. Examples of each type or activity are briefly described.     

Vague集上模糊熵的几点注记

V ague集上的不确定性度量有两种途径,一种是度量V ague集是模糊集的程度,一种是度量V ague集具有的模糊性的程度。后者将模糊集的模糊熵作为特例。本文基于“投票模型”分析了V ague集的熵应具有的特征,对国内作者提出的V ague集上的模糊熵进行了评述。     

Cross-National Stability of a Quality Management Model: A Comparative Study of the United States and Turkey

This study explores the perceptions of American and Turkish managers with respect to different dimensions of product quality. Survey data on perceptions of product quality were obtained from managers in both countries. Analyses using structural equation modeling and mean comparison tests were performed to evaluate five research hypotheses. Results provided partial support for the hypothesized differences in quality perceptions. The data indicated that although the conceptualization of quality did not differ across the two samples, there were some differences in terms of importance assigned to various aspects of quality. In particular, Turkish managers rated aspects pertaining to communication and shared definition, quality execution, and quality control higher than American managers. Implications for the rationalist and culturalist approaches to international management are discussed.     

NP-Hardness of Some Euclidean Problems of Partitioning a Finite Set of Points

Problems of partitioning a finite set of Euclidean points (vectors) into clusters are considered. The criterion is to minimize the sum, over all clusters, of (1) squared norms of the sums of cluster elements normalized by the cardinality, (2) squared norms of the sums of cluster elements, and (3) norms of the sum of cluster elements. It is proved that all these problems are strongly NP-hard if the number of clusters is a part of the input and are NP-hard in the ordinary sense if the number of clusters is not a part of the input (is fixed). Moreover, the problems are NP-hard even in the case of dimension 1 (on a line).     

Discrete mathematics in primary and secondary schools in the United States

This article provides a status report on discrete mathematics in America's schools, including an overview of publications and programs that have had major impact. It discusses why discrete mathematics should be introduced in the schools and the authors' efforts to advocate, facilitate, and support the adoption of discrete mathematics topics in the schools. Their perspective is that discrete mathematics should be viewed not only as a collection of new and interesting mathematical topics, but, more importantly, as a vehicle for providing teachers with a new way to think about traditional mathematical topics and new strategies for engaging their students in the study of mathematics.