On the Use of GLS Demeaning in Panel Unit Root Testing

One of the most well-known facts about unit root testing in time series is that the Dickey–Fuller (DF) test based on ordinary least squares (OLS) demeaned data suffers from low power, and that the use of generalized least squares (GLS) demeaning can lead to substantial power gains. Of course, this development has not gone unnoticed in the panel unit root literature. However, while the potential of using GLS demeaning is widely recognized, oddly enough, there are still no theoretical results available to facilitate a formal analysis of such demeaning in the panel data context. The present article can be seen as a reaction to this. The purpose is to evaluate the effect of GLS demeaning when used in conjuncture with the pooled OLS t-test for a unit root, resulting in a panel analog of the time series DF–GLS test. A key finding is that the success of GLS depend critically on the order in which the dependent variable is demeaned and first-differenced. If the variable is demeaned prior to taking first-differences, power is maximized by using GLS demeaning, whereas if the differencing is done first, then OLS demeaning is preferred. Furthermore, even if the former demeaning approach is used, such that GLS is preferred, the asymptotic distribution of the resulting test is independent of the tuning parameters that characterize the local alternative under which the demeaning performed. Hence, the demeaning can just as well be performed under the unit root null hypothesis. In this sense, GLS demeaning under the local alternative is redundant.     

Structural changes and unit roots in non-stationary time series

The problem of testing hypotheses of a unit root and a structural change in one-dimensional time series is considered. A non-parametric two-step method for solution of the problem is proposed. The method is based upon the modified Kolmogorov-Smirnov statistic. At the first step of this method the hypothesis of stationarity of an obtained sample is tested against a unified alternative of a statistical non-stationarity of a time series (a unit root or a structural change). At the second step of the proposed method, in case of rejecting the stationarity hypothesis at the first step, the hypothesis of an unknown structural change is tested against the alternative of a unit root. We prove that probabilities of errors (false classification of hypotheses) of the proposed method converge to zero as the sample size tends to infinity.     

购买力平价及其在亚洲新兴市场中的实证分析

 作为最重要的汇率决定理论之一,购买力平价被广泛应用于实证研究,但是重点针对亚洲新兴市场的研究依然有限。本文对七个亚洲新兴市场进行了购买力平价理论长期均衡关系的实证检验分析。针对购买力平价理论,作者运用单位根检验和协整检验进行数据分析。数据采用1957年至2011年的汇率（以美元作为基础汇率）及季度价格水平（本文采用CPI作为价格水平指数）。实证检验结果表明购买力平价理论的长期均衡在亚洲新兴市场中均不成立。文章最后提出了一些或许会导致其不理想结论的因素,并针对文章的实证研究得出新的改进方法。     

民众的文学生活权力必须得到尊重——就文学人民性和人民文学问题答刘淮南先生

人民性是一个文学无法回避的现实问题。在近20年的精英文化批判面前,民众的文学和文化需要没有得到过正常的尊重。精英文化要尊重人民群众的文化和文学生存权力;要尊重民众文学和艺术的选择权力;不能低估和贬低民众文学生活的文化价值和审美价值;不能将自己的精英文化立场“贵族化”;精英群体不能只是把矛头指向民众,精英文化是同样需要被批判的。     

Equalizing population denominators for australian metropolitan areas

Most population data are collected and tabulated in an aggregate form by censuses around the world in which political and economic considerations determine the geographic unit of the aggregation. Large spatial variation in population size among, units can limit comparative analysis among different subregions. Census population counts are often used as the denominator in rate calculations. This paper proposes the design of new districts for Australian metropolitan areas that will decrease the absolute range in population among districts. The transport algorithm is used for aggregation of Collection Districts in order to achieve this goal. The transport algorithm proved efficient in assigning CDs to a more equitable alignment of population in the selected Statistical Divisions. This method affords the spatial comparison of city settlement and socio-economic variables as well as deriving a stable denominator for these comparisons. The results demonstrate the advantages of equalized population denominators over those associated with the current statistical districts.     

农村基础设施及其空间溢出效应对农村经济增长的影响

现有经验研究的文献对农村基础设施与农村经济增长的关系具有2种相反的结论,其主要原因在于忽略了农村基础设施的存在空间溢出效应。利用1997-2008年我国省级农村经济增长数据和完全修正普通最小二乘法的面板协整估计,研究了农村基础设施及其空间溢出效应对农村经济增长的影响。结果显示：农村基础设施资本存量对我国农村经济增长具有显著的促进作用,而且农村基础设施资本存量也具有显著的空间溢出效应。这表明政府在加大对农村基础设施的投入力度的同时,还应协调相邻地区的农村基础设施投资,以充分发挥农村基础设施的最大经济效益,推动当地及相邻地区的农村经济增长。     

人性·文化·底层——红柯西域小说论

红柯是中国西域小说的重要代表,为我们描绘了一个独特的西域世界。这个世界,有一般西域小说的壮美人性和壮丽文化,显示出一种浪漫主义的特质;同时,这个世界还由于＂底层写作＂的渗透,呈现出某种贫瘠,展现出一种深沉的现实关怀精神。后一点,似乎还没有引起人们的注意。     

新疆汉语方言词根词缀化形式探

新疆汉语方言中一些词的词根在向词缀发展过程中,与普通话一样不仅仅只存在词根和词缀两极,其中也存在着某些中间状态。本文在综合运用现代汉语词汇及语法化理论方面相关知识和研究成果的基础上,对新疆汉语方言词根词缀化的形式进行概括性的描述分析。     

影视艺术"运动性"美学特征的视觉感知根源探究

"运动性"是影视艺术最重要的美学特征,其包括了被拍摄主体的运动、摄影机的运动、主客体复合运动以及剪辑带来的蒙太奇运动等方面.而影视艺术之所以具有"运动性"的美学特征,在视觉感知的层面上,源自于观赏主体的视知觉是一个积极能动的器官,其对视域中运动变化的物象有高度的敏感性和选择性.     

王力先生联绵字观念的变化及其影响

王力先生的联绵字观念分早期、中期和后期三个阶段。受20世纪50年代之社会背景的影响,其中期的联绵字观念一反早期认识,但却脱离了汉语实际。然而,其中期基本观点又为后期所延续,奠定了现代联绵字理论之肯定派联绵字观念的基础,成为现代联绵字理论的重要内容,为代代学子所学习与信守,且长期引导现代联绵字理论之肯定派从事联绵字研究及相关问题研究,因而其负面影响不容忽视。