环境规制，企业演化与城市制造业生产率

本文从企业演化的视角,以“十一五”期间全国主要污染物排放总量控制计划作为准自然实验,结合工业企业数据库和《中国城市统计年鉴》2002年~2008年的数据,运用双重差分法考察环境规制与城市制造业经济效率的因果关系.并进一步使用动态Olley-Pakes方法对城市制造业全要素生产率增长结构进行分解,剖析了环境规制的具体作用渠道.实证结果表明:相比于低减排指标城市,在排放总量控制计划实施后,高减排指标城市的制造业TFP平均提高8.8%.环境规制政策主要通过提升存活企业TFP和阻止低TFP企业进入的途径提升了生产率,但短期内也导致高TFP企业退出比例的上升和资源配置效率的降低.本研究对促进地方政府厘清环境规制和城市经济效率之间的关系、有效落实环境保护政策具有一定的参考意义.     

On the underestimation of migration’s income and poverty impact

In estimating the impact of migration on income and poverty, most existing studies have overlooked the fact that migration changes the size of the household. The ‘corrected’ impact that accounts for changes in household size is presented analytically and is estimated on the basis of data from nationally representative household surveys in Albania and Ghana. The analysis considers three poverty measures and four groups of migrant households: those with internal, international, internal and international, and internal and/or international migrants. The ratio of the corrected to the uncorrected impact on per capita income for Ghana (Albania) averages from 2.7 to 4.5 (2.5–3.8), and the ratio for the poverty impact averages from 2.6 to 4.4 (2.1–6.4). Thus, abstracting from changes in household size may result in a substantial underestimate of the impact of migration on income and poverty.

“信息人假说”的当代建构

信息是构成世界与人的基质。信息社会与网络时代所构建的“虚拟时空”,改变着人类的生产方式和生活方式,也改变着人们对人性的传统认知,使得以往种种关于人的本性假说在信息网络时代面前显得缺乏解释力和说服力。在网络空间中,“信息人”是活动主体,是网络伦理所要调节规范的道德对象,同时也是网络精神的主要体现者。网络社会所赋予“信息人”的自由、平等与多元,不仅仅是一种道德原则和伦理要求,也是信息人作为网络伦理的主体所应享有的权利,更是一种深刻的人性需要。这种人性需要,为信息科技推进网络自由、共享、平等、多元提供了社会动力,也使得“信息人假说”有了现实的基础与依据。“信息人假说”通过人的生存状态的更本质层面即信息交互作用层面,重新透视人的存在与人的本质,将为人们超越以往传统社会的人性假说,获得网络时代人的行为解释的特定视角,求得对信息时代网络伦理与全球伦理发展的重要突破开拓一条全新的道路。     

Do economic growth and institutional quality reduce poverty and inequality in West Africa?

Over the past two decades, the West African region has experienced much faster economic growth than other parts of the world. However, despite this economic upturn, the region has continued to experience high levels of inequality and poverty, yet economic growth is considered to be one of the main drivers of poverty reduction. An interesting literature indicates that local conditions may limit the expected effects of economic growth on poverty and income inequality. In this study, we are interested in the role of institutional factors that have been largely ignored in explaining poverty reduction and inequality outcomes in this region. Thus, this study empirically examines the role of economic growth and institutional quality on inequality and poverty reduction in West Africa. Using data from the World Development Indicators (WDI), the International Country Risk Guide (ICRG) and the Standardized World Income Inequality Database (SWIID), our results show that economic growth remains a necessary condition for poverty reduction and that the overall improvement in the quality of institutions contributes significantly to reducing poverty and income inequality in the long term. This contribution is made in particular through the improvement of democratic institutions, the alleviation of bureaucratic constraints, the quality of the judicial and regulatory system, the control of corruption and the quality of government stability. Furthermore, we show that improvements in the judicial system, low levels of corruption and better bureaucratic quality happen to be prerequisites for economic growth to significantly reduce income inequality. These results therefore call on policy makers in the West African region to improve their institutional framework and especially these dimensions with a view to enabling the region citizens to improve their living conditions.     

美国贸易赤字的成因分析--兼论美元贬值的成效

从汇率、国内吸收以及直接投资与贸易的关系三个角度,利用美国1980-2004年的年度数据,通过简单OLS方法得出美国的进出口方程,可以揭示影响美国贸易逆差的主要原因,以及美元贬值对贸易逆差的影响,结果表明:(1)美元贬值主要通过影响出口而非进口改善贸易收支,但存在2年左右的滞后期,因此美元截至目前的贬值并没有明显改善贸易逆差;(2)从收入影响看,由于H-M收入非对称效应的存在,要减少贸易逆差需要美国相对国外更大幅度的紧缩;(3)从直接投资与贸易的关系看,美国对外直接投资转移了本国的供给,增大了美国进口。大规模减少美国贸易逆差不可能仅仅依靠美元汇率贬值,而是需要中长期的结构性调整,2006年美国贸易逆差将进一步扩大。     

An Availability System with General Repair Distribution: Statistical Inference

This article we study the statistical inferences of an availability system with imperfect coverage. The time-to-failure and time-to-repair of the active and standby components are assumed to be exponential and general distribution, respectively. Assume that the coverage factor is the same for an active-component failure as that for a standby-component failure. Firstly, we propose a consistent and asymptotically normal (CAN) estimator of availability for such repairable system. Based on the CAN estimator of the system availability, interval estimation and testing (hypothesis) are performed. To implement the simulation inference for the system availability, we adopt two repair-time distributions, such as lognormal and Weibull distribution, in which three types of Weibull distribution are considered according to the shape parameter β. The component holds the decreasing repair rate (DRR), constant repair rate (CRR), and increasing repair rate (IRR) if β < 1, β = 1, and β > 1, respectively. Finally, all simulation results are displayed by appropriate tables and curves for understanding performance of the statistical inference procedures presented in this article.     

NONNORMAL REGRESSION. II. SYMMETRIC DISTRIBUTIONS

Salient features of a family of short-tailed symmetric distributions, introduced recently by Tiku and Vaughan [1] Tiku, M. L. and Vaughan, D. C. 1999. “A family of short-tailed symmetric distributions”. In Technical Report Canada: McMaster University.  [Google Scholar], are enunciated. Assuming the error distribution to be one of this family, the methodology of modified likelihood is used to derive MML estimators of parameters in a linear regression model. The estimators are shown to be efficient, and robust to inliers. This paper is essentially the first to achieve robustness to inliers. The methodology is extended to long-tailed symmetric distributions and the resulting estimators are shown to be efficient, and robust to outliers. This paper should be read in conjunction with Islam et al. [2] Islam, Q., Tiku, M. L. and Yildirim, F. 2001. Nonnormal regression, Part I: Skew distributions. Commun. Stat.—Theory Meth., to appear [Google Scholar]who develop modified likelihood methodology for skew distributions in the context of linear regression.     

Bayes Estimates of Markov Trends in Possibly Cointegrated Series

Stylized facts show that average growth rates of U.S. per capita consumption and income differ in recession and expansion periods. Because a linear combination of such series does not have to be a constant mean process, standard cointegration analysis between the variables to examine the permanent income hypothesis may not be valid. To model the changing growth rates in both series, we introduce a multivariate Markov trend model that accounts for different growth rates in consumption and income during expansions and recessions and across variables within both regimes. The deviations from the multivariate Markov trend are modeled by a vector autoregression (VAR) model. Bayes estimates of this model are obtained using Markov chain Monte Carlo methods. The empirical results suggest the existence of a cointegration relation between U.S. per capita disposable income and consumption, after correction for a multivariate Markov trend. This result is also obtained when per capita investment is added to the VAR.     

Book Review: New Introduction to Multiple Time Series Analysis

ABSTRACT

This paper proposes a test for the null hypothesis of periodic stationarity against the alternative hypothesis of periodic integration. We derive the limiting distribution of the test statistic and its characteristic function, which are the same as those of the test developed in Kwiatkowski, Phillips, Schmidt and Shin.[15] Kwiatkowski, D., Phillips, P.C. B., Schmidt, P. and Shin, Y. 1992. Testing the Null Hypothesis of Stationarity against the Alternative of a Unit Root.. Journal of Econometrics, 54: 159–178. [Crossref], [Web of Science ®] , [Google Scholar] We find that some parameters, which we must assume under the alternative, have an important effect on the limiting power, so we should choose such parameters carefully. A Monte Carlo simulation reveals that the test has reasonable power but may be affected by the lag truncation parameter that is used for the correction of nuisance parameters.