旅行商问题算法研究综述

旅行商问题是一个经典的NP完全问题,由于其在许多领域内具有实际的应用价值,一直有众多学者对其进行研究。本文从介绍TSP模型入手,根据旅行商问题的分类,概要介绍了近五年来旅行商问题算法的研究状况,并对旅行商问题未来的研究作了展望。     

Pupil Speech during Morning News: the effects of reducing teacher questions and increasing pauses and praise

Classroom discourse patterns were examined in the morning news sessions of a primary school classroom. The effects of reducing teacher questions and increasing rates of teacher pauses, praise and directives were investigated. Child words spoken and child expansions were recorded, as well as class call‐outs and teacher control statements. Frequencies of child words spoken showed no significant changes across the phases of the study. However, reducing teacher questions and increasing teacher pauses significantly decreased child expansions, while reducing teacher questions and increasing teacher praise significantly increased child expansions. Replacing teacher questions with directives had no significant effect upon child expansions. Class call‐outs and teacher control statements showed no significant changes across the intervention phases. The results of this study suggest that, for this teacher and class, teacher questions may be decreased without adversely affecting either child utterances or class behaviour, and that replacing questions with praise may increase children's contributions — particularly in the form of verbal expansions — to morning news talks.     

Degrees of value: comparing the contextual complexities of UK transnational education in Malaysia and Hong Kong

This paper reveals the complex diversity that underpins ostensibly similar transnational education programmes (TNE), through a comparison of UK TNE in Malaysia and Hong Kong. It draws on data from two different yet cognate studies on the role of UK universities in delivering higher education in Asia. Some fine-grained and informative differences between the ways in which ‘value’ in TNE is constructed in different host contexts is revealed. The paper brings to light the ‘voices’ of TNE students and graduates, which are very seldom heard. The arguments adapt and extend the concepts of education as a positional good, and as cultural capital. For various instrumental, intrinsic and personal reasons the authors discuss in detail, UK TNE is more highly valued in Malaysia than in Hong Kong. The paper makes a wider contribution to knowledge on the changing landscape of international higher education and the impact on social and personal (dis)advantage.     

Gender differences in the academic career

This study examines sources of satisfaction, indicators of stress, academic performance, and reward structure in the academic careers of male and female faculty at a major midwestern state university. Faculty pairs were selected from five academic divisions. A total of 58 matched pairs were identified. Of these, 63 faculty responded, yielding data for 23 matched pairs. Subjects were mailed the Academic Career Development Survey, consisting of 144 items. Results indicated that self-reported physical and mental health, and professional and personal life satisfaction were high for both males and females. Both males and females placed high importance on their career and on marriage/other intimate relationships; however, both reported high levels of dissatisfaction with these factors. Gender differences were found in both satisfaction and type of stress reported; no gender differences were found in composite teaching and research performance indices. Salary data, obtained for 42 matched pairs, indicated similar salary levels for men and women. Results were discussed with respect to prior research on gender differences and the academic career.     

养禽业中沙门氏菌的危害及防控措施

家禽沙门氏菌感染是一个世界性的问题,它对养禽业和人类的健康造成了巨大的危害,通过建立生物安全屏障、免疫接种和检测的方式来防控家禽沙门氏菌感染,是目前最为可行的措施。     

Communicating data to schools

The article explores the communication of data to schools by researchers and evaluators. The stance is taken that the research process is one in which the participants are involved in a mutually supportive enterprise in which the relationship should be viewed as co-operation between professional colleagues, i.e., a relationship in which perceived status is minimised but one in which different knowledge and expertise exists on both sides. It is argued that the obtaining of data at school sites requires the researcher to provide data to their sources. Careful consideration needs to be given by researchers to the process and methods of communication of data to school communities. Issues addressed include audience, terminology, prose and other forms of presentation. A case is made for the researcher to become involved in dialogue to enhance the “meaning-making” of practitioners and themselves. The article concludes with a set of guidelines for researchers.