Am I missing something? The effects of absence from class on student performance

We analyse a rich dataset of Economics students at a UK university to identify causal effects of class absence on student performance, exploiting the random assignment of students and information on students’ class timetables to avoid selection problems. We use panel properties of the data to control for unobserved student factors such as ability and effort. Quantile regression results suggest that absence has adverse effects on performance – but these effects are causal only for the upper part of the conditional performance distribution.     

多晶含铜MCM-41型纳米材料的合成研究

将铜稳定、均匀分散在MCM 41型中孔材料的结构中 ,可充分发挥铜活性中心的催化活性。特定条件下 ,采用季铵盐类模板剂 ,在正硅酸乙酯 (TEOS)的水解聚沉时 ,向材料的结构中引入金属铜源 ,成功合成了分子自组装Cu MCM 41型分子筛。经XRD、FT IR、ED、HTEM、TG DTA分析 ,证实了样品属多晶态纳米材料 ,铜的骨架含量及脱模条件如焙烧温度、焙烧时间 ,对材料结构的稳定性及中孔有序度均有较大影响。     

Strategic interaction among public school districts: Evidence on spatial interdependence in school inputs

This paper provides evidence on strategic interaction among public school districts in Massachusetts. The open enrollment program in Massachusetts is unique in testing the strategic competition thesis because it allows students to attend public schools located outside their home district. For each student who transfers out, funds are deducted from the sending district's local aid distribution and added to the receiving district's local aid. Thus, school districts no longer have the assurance of a ready supply of students and funding, instead they have to compete with neighboring districts, and enact strategies that will help retain as well as attract more students. A spatial econometric framework is applied to disentangle the correlation due to strategic interaction from the one that is simply due to spatially correlated error shocks. The results show that public school districts respond positively to the expenditure decisions of neighboring districts, thereby acting strategically when setting their own spending levels.     

The effect of community college enrollment on bachelor's degree completion

Rouse [Rouse, C. E. (1995). Democratization or diversion—the effect of community-colleges on educational-attainment. Journal of Business and Economic Statistics, 13(2), 217–224] finds that enrollment in a community college may divert students from attaining a bachelor's degree. However, this result may be due to selection bias, as the population of community college students should be quite different from those who attend 4-year institutions in terms of both observable and unobservable characteristics. This study uses propensity score matching to non-parametrically balance a data set from the 1996 Beginning Postsecondary Students survey in order to overcome issues associated with selection bias. Results from a Cox proportional hazards model indicate that attendance at a community college lowers the hazard rate for completing a bachelor's degree. The results are consistent with previous studies.     

咨询公司的知识管理应用探讨

根据信息技术在知识管理中的应用情况,把咨询公司的知识体系划分为三大类型,并研究这三大类知识之间的相互转换关系。分析咨询公司的知识管理业务特点,应用目前知识管理的主要技术,对这三大类知识提出优化管理策略,使其更有效发挥作用。最后,分析国外5家著名咨询公司的知识管理实例,希望对我国咨询公司的知识管理运作提供参考。     

小型高新技术企业技术创新的因素分析

本文从小型高新技术企业自身的特点出发，系统分析了小型高新技术企业技术创新的四大关键因素：人力资本、信息、资金和环境，由于这四个因素当前仍存在一些不足之处，在一定程度上阻碍了小型高新技术企业技术创新的顺利进行。     

我国地区固定资产投资宏观调控研究初探

本文首先对我国改革开放力度大的地区可以实现经济高速增长但不能促进投资有效性提高的致因进行了分析；然后以市场调节与政府调控结合以及配合西部大开发战略的实施为固定资产投资的指导思想，有针对性的提出了我国进行地区固定资产投资宏观调控的建议。