Panel LM unit root tests with level and trend shifts

This paper considers a Lagrange multiplier (LM) based panel unit root test that allows for heterogeneous structural breaks in both the intercepts and slopes of a series. We note that many popular time series variables are likely to exhibit changing means and/or trends over time. Given that the usual tests will depend on the nuisance parameters indicating the locations of the trend breaks, we adopt a transformation procedure that makes our new panel unit root tests invariant to the nuisance parameters. To illustrate the importance of the power gain provided by our test, we examine the convergence hypothesis using relative ratios of per capita health care expenditures in 20 OECD countries. Our results provide evidence that the convergence hypothesis is supported.     

抽油机V带执行标准现状及有关问题探讨

阐述了国内外V带现行标准状况，指出通用V带标准应用于抽油机V带存在的问题。针对抽油机用V带寿命不足5000h的问题，提出制定符合中国油田实际的《抽油机用V带》新标准，并从五个方面提出了编写新标准的建议。     

Evidence on the existence of speculative bubbles in farmland prices

We conduct tests for the contribution of speculative bubbles to farmland prices. These tests are carried out under the hypothesis that farmland investors rationally form expectations. The outcome of tests reported here allows us to infer whether farmland prices are determined by market fundamentals-discounted returns from the highest economic land use-or whether rumors about farmland price movements are self-fulfilling. The tests are stationarity and cointegration tests relating farmland prices to rents. The tests are carried out using data from three farm production regions-the Corn Belt, the Northern Plains, and the Lake States. In each region, we find little evidence to reject the hypothesis that market fundamentals determine farmland prices.     

The adequacy of asymptotic approximations in the near-integrated autoregressive model with dependent errors

We consider the normalized least squares estimator of the parameter in a nearly integrated first-order autoregressive model with dependent errors. In a first step we consider its asymptotic distribution as well as asymptotic expansion up to order O_p(T⁻¹). We derive a limiting moment generating function which enables us to calculate various distributional quantities by numerical integration. A simulation study is performed to assess the adequacy of the asymptotic distribution when the errors are correlated. We focus our attention on two leading cases: MA(1) errors and AR(1) errors. The asymptotic approximations are shown to be inadequate as the MA root gets close to −1 and as the AR root approaches either −1 or 1. Our theoretical analysis helps to explain and understand the simulation results of Schwert (1989) and DeJong, Nankervis, Savin, and Whiteman (1992) concerning the size and power of Phillips and Perron's (1988) unit root test. A companion paper, Nabeya and Perron (1994), presents alternative asymptotic frameworks in the cases where the usual asymptotic distribution fails to provide an adequate approximation to the finite-sample distribution.     

当代艺术审美理想的迷失与重建

中国当代艺术审美理想的迷失从根子上说是有些中国作家和艺术家社会背叛的结果,从美学上说,不但是席勒当年所批判的恶劣倾向的沉渣泛起,而且消解了人对自己的尊严的捍卫和对自由的追求。中国当代艺术审美理想的重建就是要求中国作家和艺术家精神寻根,按照美的规律创造。     

加强地勘单位领导班子自身建设初探

文章认为,要建设一个优秀的地勘单位领导班子,应努力做好思想政治及组织建设工作,正确处理民主与集中、集体与个人、局部与全局等方面的关系。     

小学体育新课标目标统领下单元教学计划的研究

新的全日制义务教育《体育(1至6年级)课程标准,》对体育课提出了运动参与、运动技能、身体健康、心理健康和社会适应等五大领域的教学目标。文章通过实验,在对比中阐述了以新课程标准为教学目标,进行有针对性的教学设计和课堂实施,可使学生各方面的发展更符合新时期的要求的观点,并提出了单元教学计划设计的方法。     

物流中的新设施—自动化立体仓库

当今物流速度日益加快，仓库建设和改造向空间、立体化、自动化快速发展，建设自动化立体仓库是今后的必然趋势。结合多年实践．对物流领域成件货物储存的新设施，自动化立体仓库进行了详细阐述。     

效率工资的决定机理及在薪酬管理中的作用

效率工资理论认为 ,支付比市场工资更高的工资 ,劳动总成本可能更小 ,企业能获得更多的利润。工作转换模型表明 ,在其他条件不变时 ,企业支付较高的工资可以降低工人的工作转换率。效率工资理论在理论上和现实的薪酬管理中都展示了极其强大的威力。