Long memory in volatilities of German stock returns

We show that there is strong evidence of long-range dependence in the volatilities of several German stock returns. This will be done by applying a method using the difference of the classical log-periodogram regression estimator for the memory parameter and of the tapered periodogram based estimator. Both estimators give similar values for the memory parameter for each series and this indicates long memory. To support our findings we apply also a methodology using the sample variance and a wavelet based estimator to the data. Also these two methods show clear evidence of long-range dependence in the volatilities of German stock returns.First version received: December 2001/Final version received: March 2003The computational assistance of Eleni Mitropoulou and Björn Stollenwerck as well as the helpful comments of two unknown referees are gratefully acknowledged. Research supported by Deutsche Forschungsgemeinschaft under SFB 475. Stock returns were obtained from Deutsche Finanzdatenbank (DFDB), Karlsruhe.     

Earnings Differentials between State and Non-State Enterprises in Urban China

The present paper estimates earnings differentials between state and non-state sectors for Chinese urban residents in 1996 by taking into account differences in non-wage benefits. Household survey data are used to estimate wage differentials while aggregate statistics are utilised in estimating non-wage benefits. We find that state-sector workers earned significantly more than workers in urban collective and domestic private enterprises in 1996. Unskilled workers in foreign invested enterprises (FIE) earned significantly less than those in the state sector but skilled workers earned more in FIE than in the state sector. These findings shed light on the source of labour immobility that state-owned enterprise had experienced until recently.     

Reinterpreting the performance of immigrant wages from panel data

Immigrants differ from the native born in terms of unobserved factors, such as motivation, and observed factors, including those related to the interruption of labour market activity and earning capacity, which may bias estimates of immigrant integration. Using panel data from the Survey of Labour and Income Dynamics, we show that using potential experience, rather than actual experience, exaggerates estimates of the disruption and recovery caused by immigration. More importantly, we find support for omitted variables bias, arising from unobserved fixed effects. Instrumental variable estimates for both pooled and separate samples of immigrant and native born men demonstrate a wage disadvantage for immigrants upon entry that persists through their lifetime. Standard estimates of a modest wage advantage for the children of immigrants also suffer from omitted variables bias arising from unobservables. Contrary to most of the literature to date, our instrumental variable estimates which allow for unobservable fixed effects suggest that immigrants never catch up to otherwise comparable native born workers, but their children do just as well. We would like to thank Statistics Canada for permitting access to the data and solving associated technical problems, the Prairier Centre for Research on Immigration and Integration for financial assistance, and Peter Schnabl for excellent research assistance. An earlier version of this paper was presented to the 10th International Conference on Panel Data in Berlin, July 5–6, 2002. The authors take sole responsibility for errors, omissions and interpretation of the data.     

Enforcing Emissions Trading when Emissions Permits are Bankable

We propose enforcement strategies for emissions trading programs with bankable emissions permits that guarantee complete compliance with minimal enforcement costs. Our strategies emphasize imperfect monitoring supported by a high unit penalty for reporting violations, and tying this penalty directly to equilibrium permit prices. This approach is quite different from several existing enforcement strategies that emphasize high unit penalties for emissions in excess of permit holdings. Our analysis suggests that a high penalty for excess emissions cannot be used to conserve monitoring effort, and that it may actually increase the amount of monitoring necessary to maintain compliance.The authors are grateful to Anthony Heyes and three anonymous referees for their valuable comments. Partial support for this research was provided by the Cooperative State Research Extension, Education Service, U. S. Department of Agriculture, Massachusetts Agricultural Experiment Station under Project No. MAS00871.     

论生态经济理论与科教兴农战略

融生态经济理论于科教兴农战略之中,以协调人与自然、经济与生态的关系,指导技术政策的制订和技术措施的选择以及科技兴农成果的评价,是中国式农业现代化的正确选择。     

生产函数与农史研究——评彭、黄大辩论

最近几年来,中国经济史研究中最轰动的大事就是美国加州大学的彭慕兰教授与黄宗智教授有关《大分流》一书的论争。①。细读双方争论的文章内容,可以发现,双方是历史学者,在讨论经济史时,对生产函数的概念与含苞欲放义并没有正确的理解。如果能够廓清一下,争论双方的逻辑可以变得更周严,双方之间的争论也许可以缓解一些。在此我只提三点,加以简述: (1)生产函数中边际产量下降的经济含义; (2)劳动生产力增加的泉源; (3 )边际产量之分析对中国小农的适用性。一　边际产量下降的含义黄宗智每次提到“内卷化”,总是写明定义是“劳动边际报酬…     

保护创新的机制

在很大程度上，创新保护是一个比创新本身更为重要的问题。基于国外学者的研究工作，考虑了中国创新知识产权保护的法规，指出创新保护机制的重要性，分析了我国各种创新保护机制的特点，并识别了其各自的优势和劣势。     

我国收入贸易条件变动分析:1995～2004

收入贸易条件衡量的是一国在国际分工中获得的总体贸易利益的多少,在对我国贸易条件的变化进行分析时应当合理考虑收入贸易条件指数的变动。近年来我国的收入贸易条件指数呈现出持续改善的趋势,这表明外贸规模的扩大对国民经济发展做出了积极的贡献,仅仅根据商品贸易条件指数下降而得出我国贸易条件出现严重恶化的结论缺乏充分的根据。从国际经济竞争的现实背景来考虑,我国应当在保持收入贸易条件指数不恶化的情况下,继续大力推动出口贸易量较快地增长。     

构建农村义务教育经费政府分担机制的思路与对策

农村义务教育是提高农民素质、增进农民福祉的重要保证,也是当前农民群众最关心、要求最迫切的事情,应作为建设社会主义新农村的一项重要任务来抓.要使农村义务教育走出困境,必须把财税体制改革与农村义务教育结合起来,以科学发展观和构建和谐社会的理念重新审视农村义务教育经费的供给问题,克服取消农业税给农村义务教育经费保障机制带来的冲击,努力建立与财税体制改革和农村税费改革相适应的新型经费保障机制,即在公共财政框架下,根据财权与事权相对称以及地区间教育公平原则,以中央和省级政府为主体,各级政府合理分担的农村义务教育经费政府保障新机制.     

基于认知视角的创业机会发展过程研究

理性创业时代背景下，如何把握创业机会已成为创业者普遍关心的问题。选取34位创业者作为研究样本，运用文本挖掘和多案例匹配分析方法对创业机会发展过程进行分析、编码，探究创业行为背后的认知机制。研究发现，在机会发现或创造阶段，创业者通过反事实思维推动的创业警觉和创业拼凑两种途径形成创意，并经过新旧认知体系的排斥与趋同形成心智模型，以揭示创业机会发现或创造的认知机制；在机会评估阶段，创业者通过对风险—收益感觉与知觉的多轮反复交互，形成第一人称机会信念和第三人称机会评估，由此揭示创业机会评估的认知机制；在机会开发阶段，创业者形成机会开发内外两种机制，外在机制围绕“探索导向—商业模式创新—新企业成长”展开，内在机制围绕换位思考、效果推理等认知因素推动企业创新、资源获取展开。结论对丰富创业认知理论和管理实践具有重要意义。