国外教师期望效应研究进展与当代教育启示

教师期望效应是教师对学生的期望在学生的未来发展中得到证实的现象,它反映了教师对学生的态度会影响学生发展的方向和程度,开展该现象的研究对教师观念的改变和学生的健康发展均有重要意义。对教师期望效应的种类、理论模型及国外的相关研究进行了介绍,探讨了其对教育现实的一些重要启示。     

A modified random-effect procedure for combining risk difference in sets of 2×2 tables from clinical trials

Summary Meta-analyses of sets of clinical trials often combine risk differences from several 2×2 tables according to a random-effects model. The DerSimonian-Laird random-effects procedure, widely used for estimating the populaton mean risk difference, weights the risk difference from each primary study inversely proportional to an estimate of its variance (the sum of the between-study variance and the conditional within-study variance). Because those weights are not independent of the risk differences, however, the procedure sometimes exhibits bias and unnatural behavior. The present paper proposes a modified weighting scheme that uses the unconditional within-study variance to avoid this source of bias. The modified procedure has variance closer to that available from weighting by ideal weights when such weights are known. We studied the modified procedure in extensive simulation experiments using situations whose parameters resemble those of actual studies in medical research. For comparison we also included two unbiased procedures, the unweighted mean and a sample-size-weighted mean; their relative variability depends on the extent of heterogeneity among the primary studies. An example illustrates the application of the procedures to actual data and the differences among the results. This research was supported by Grant HS 05936 from the Agency for Health Care Policy and Research to Harvard University.     

将分段函数表示为初等函数的方法

本文给出了一种化具有多个分段点，且在各区间段上的表达式为多项式函数的分段函数为初等函数的具体方法．     

英语否定词在语言表达中的应用

否定词的用法对学习英语的学生来说一直是个难题。因为在英语中否定词的用法和意义是灵活多变的。本文主要从四个方面阐述了英语否定词在语言表达中的具体应用。旨在帮助学生更有效 ,灵活地理解和使用。     

文学思潮中的“花花公子”——简论“欲望化写作”

欲望化写作是当今文坛上方兴未艾的且引人注目的文学现象,其注重张扬感官放纵和感官感受。本文拟从欲望化写作的成因、分类以及欲望化写作的积极影响和消极影响等几个方面来探讨欲望化思潮。     

The impact of sales promotions on store performance: a structural vector autoregressive approach

The present paper analyses the impact of sales promotions on store performance, in the short and long term, from the retailer's point of view. Relationships among promoted and regular sales in the hypermarkets of a large-scale retail chain of national importance, are investigated by means of a structural vector autoregressive model (SVAR). Statistically significant effects of sales promotions in the heavy household section on store sales are found in the short-run; these promotions produce additional sales and thus act as an attractive factor. Promotions in textile category, on the contrary, produce an immediate negative effect on net sales. In the long run, negative statistically significant effects on regular sales are detected when promotions are repeatedly implemented within perishables category.     

Generalized additive models for location, scale and shape

Summary.  A general class of statistical models for a univariate response variable is presented which we call the generalized additive model for location, scale and shape (GAMLSS). The model assumes independent observations of the response variable y given the parameters, the explanatory variables and the values of the random effects. The distribution for the response variable in the GAMLSS can be selected from a very general family of distributions including highly skew or kurtotic continuous and discrete distributions. The systematic part of the model is expanded to allow modelling not only of the mean (or location) but also of the other parameters of the distribution of y , as parametric and/or additive nonparametric (smooth) functions of explanatory variables and/or random-effects terms. Maximum (penalized) likelihood estimation is used to fit the (non)parametric models. A Newton–Raphson or Fisher scoring algorithm is used to maximize the (penalized) likelihood. The additive terms in the model are fitted by using a backfitting algorithm. Censored data are easily incorporated into the framework. Five data sets from different fields of application are analysed to emphasize the generality of the GAMLSS class of models.     

关于教育对经济增长抑制效应的思考

教育对经济增长的抑制效应是教育对经济增长双重效应的一个重要方面。本文从确认教育对经济增长的抑制效应的存在出发,分析了教育对经济增长抑制效应的具体情形,探讨了教育对经济增长抑制效应的存在机制。     

大学精神的失落及其对策研究

文章认为,大学精神的失落是当前我国大学存在的一个突出问题.在剖析其各种表现之后,文章进一步探讨了其产生的原因及危害,并就如何重建大学精神提出了一些建议.     

频率效应在二语习得中的作用

本文通过研究各种二语习得理论对频率效应的论述及相关实证,力图探索频率效应在二语习得中的重要作用.作者认为:尽管频率不能解释所有语言学习现象,其效应却体现在二语习得的各个方面,频率应是二语习得理论不可或缺的部分.