Learning Why More Learning Takes Place in Some Classrooms Than Others

Abstract. The relatively poor average performance of German students on the recent PISA international evaluations of 15- and 16-year-olds' literary skills (2000) and mathematical skills (2003) and the wide variation in performance, with low-income students scoring particularly poorly, have led to calls for reforms of the German educational system. Understanding why students in some classrooms learn more than do those in other classrooms is an important first step in considering alternative reform strategies. Possible explanations include differences in teacher quality, class sizes and peer groups, and also differences among the types of secondary schools that parents select for their children. This paper illustrates a set of techniques that are useful in examining the roles these factors play in predicting why, net of family background and prior achievement, the average achievement of children in some classrooms is much higher than that of children in other classrooms. We illustrate the use of these techniques with a dataset from Bogotá, Colombia, that has two attractive properties. First, some teachers teach multiple classes of students. Second, students are enrolled in schools in two sectors (public and private). Application of the techniques described in this paper could shed light on the reasons why the average academic achievement of German students attending some schools is much higher than that of German students attending other schools.     

高校智力资本运作效率的数据包络分析

文章在综合分析高校智力资本的基本概念和主要内容的基础上，提出了用数据包络分析方法评价高校智力资本运作效率的基本思路与方法，并以8所高校在同一学科中的智力资本运作情况为算例，对数据包络分析的算法和所使用的计算工具作了说明。     

C2C交易中消费者购物心理研究

目前我国经常上网购物人数和网民上网购物比例不断增大，消费者对消费者之间的电子商务交易（C2C）也在迅速发展。对于C2C交易中的卖家而言，掌握消费者在C2C交易中的购物心理对提高销售业绩显得特别重要。文章对消费者在C2C交易中的购物心理进行研究。     

B2B电子商务模式的探讨

针对B2B模式将成为未来电子商务发展的主流,文章先从价值链角度分析了B2B电子商务模式对价值链上游的冲击,然后概括性地总结了目前主要的3种B2B电子商务模式,最后用“SWOT”战略评估方法分析了基于供应链管理的区域型B2B电子商务新模式。     

Delays and equilibria with large and small information in social learning

The general model of social learning with irreversible investment and endogenous timing is analyzed for any distribution of private informations. Strategic complementarities and multiple equilibria appear which are generated solely by information externalities. Different equilibria generate strikingly different amounts of information. The impacts of various assumptions (bounded beliefs, large number of agents, discrete time and short periods) are examined carefully. The properties are robust to the introduction of observation noise with a continuum of agents.     

控制火电厂二氧化硫排放的有效途径——排污权交易

目前,我国工业二氧化硫排放量中有42%是火电厂排放的,因此高效控制火电厂的二氧化硫排放是提高空气质量的主要途径。美国利用排污权交易治理火电厂的二氧化硫排放取得了巨大的成功,不仅二氧化硫排放量大幅下降,而且排污权交易也被证明是成本最低的方法。借鉴美国的经验,可以为我国治理火电厂二氧化硫排放提供高效途径。     

基于BP神经网络的我国M2/GDP预测与对策

本文计算了1993年至2005年我国M2/GDP,发现该数据总体呈上升趋势,这一定程度上反映了我国体制上的深层次问题。另外,本文运用带有动量项和自适应学习率的BP神经网络方法预测出我国2006年的M2/GDP是1.6386左右,并提出了一些相应的政策建议。     

我国的M1/M2(1978-2002):长期趋势、水平与周期波动

本对我国1978—2002年的M1／M2的长期趋势、水平和周期波动进行了研究，结果表明1978—1995年，中国的M1／M2呈急剧下降的态势，但是从1996至今则基本保持平稳。另外从国别比较来看，我国属于M1／M2比较高的国家(地区)之一，这表明我国的居民和企业由于支付制度、取款成本、规避税收等原因比美、日等国家的经济主体对M1的需求高很多。除开长期走势之外，中国的M1／M2还伴随着经济活动呈周期性的波动，实证分析结果表明1996年前的经济增长率是M1／M2周期波动的Granger原因，但1996年以后则必须由名义利率、通货膨胀率和股票市场交易量的变动才能说明M1／M2的波动。     

维生素C二步发酵中优良菌株201A的研究

在对维生素C生产菌选育过程中,发现一株葡萄糖酸杆菌正向突变株,分离纯化后,获得优良菌株201A,经摇瓶培养,做生长曲线测定,发现前期生长及产酸明显高于生产菌株201C,经流加发酵工艺培养,可缩短发酵周期8h,山梨糖生成2—酮基—L—古龙酸的摩尔转化率达80％。     

Industrial distributors: Can they survive in the new economy?

As e-commerce evolves and gains power in the business-to-business (B2B) marketplace, what lies ahead for the industrial distributor? The fundamental issue from the distributor's point of view is how to compete more effectively and profitably, given the changing business environment of the new economy. This paper reviews the literature on the distributor's role and relationships and introduces a conceptual model of distributor viability. The model identifies sources of value that distributors offer to manufacturers and customers, including customer relationship management (CRM), production and operations management (POM), and knowledge management (KM). The paper explores the managerial implications of distributor relationships and sources of value. This provides the foundation for better understanding of the viability of industrial distributors in the new economy.