工具变量法综列单位根检验的有偏性及其修正

Chang（2002）基于非线性工具变量估计，提出了对截面相关综列数据进行单位根检验的SN检验，在综列数据生成过程不舍飘移和时间趋势时具有良好的表现。但我们的研究表明，在非平稳综列数据含有确定性趋势时，SN检验是有偏的，不再服从标准正态的渐近分布，而需要进行修正。本文基于蒙特卡罗仿真试验提出了一种简便的修正方法，修正后的SN检验统计量渐近分布为标准正态分布。仿真结果表明，修正后的SN检验具有更好的有限样本性质和较高的检验势。     

欧盟REACH法令对中国化工产品出口的影响分析

欧盟REACH法令的实施将促进我国化学工业的发展,但在短期内会导致我国出口欧盟化工产品和进口化工产品成本上升,降低出口产品竞争力,部分产品甚至退出欧盟市场,其他国家可能纷纷效仿欧盟,引起连锁反应。应对该种技术性壁垒,我国政府和行业协会应加大宣传REACH法令的力度,加快国内相关立法,推进国内实验室的GLP认证工作。另外,化学品生产企业应提高自身产品质量,做好化学品注册的可行性分析和预注册工作。     

How many voters are needed for paradoxes?

Summary. This paper presents a general procedure for finding profiles with the minimum number of voters required for many important paradoxes. Borda's and Condorcet's classic examples are revisited as well as generalizations. Using Saari's procedure line, we obtain an upper bound for the minimum number of voters needed for a profile for which the Condorcet winner is not strictly top ranked for all weighted positional procedures. Also we give a simple upper bound on the minimum number of voters needed for a set of prescribed voting outcomes. In contrast to situations wherein small numbers of voters are needed, we consider paradoxes requiring arbitrarily large numbers of voters as well as large numbers of alternatives. Finally we indicate connections with statistical rank based tests. Received: April 18, 2001; revised version: May 25, 2001     

我国公共投资规模效率实证分析

我国公共投资规模连年扩大,改善了生活环境和生产条件,但是否存在投资过度的风险?本文运用生产函数模型分析了公共投资规模效率存在的条件,使用协整的方法分析了大口径和小口径公共投资规模的最优规模,得出我国公共投资规模不足的结论。     

湘北环湖红壤丘岗区生态经济特征及发展途径初探——以盘塘红壤实验区为例

本文通过对盘塘红壤开发实验基地区域生态经济特征及存在问题的分析,初步提出了该区生态经济深度发展的主要途径,并就整个湘北环湖红壤丘岗区生态经济发展提出了几点粗浅看法。     

中国饲料工业期货的价格发现实证研究

本文借助向量自回归模型、协整检验、误差修正模型、方差分解、脉冲响应函数等方法,以中国唯一的饲料工业期货———大连商品交易所豆粕期货品种为例,研究了期货价格与现货价格之间的动态关系,定量刻画了期货市场在价格发现中的作用。研究结果显示:豆粕期货价格与现货价格存在相互引导关系,并且期货与现货价格之间存在长期均衡关系,对豆粕期货来说,期货市场在价格发现功能中起到主导作用。     

状态方程计算高分子共混物的比体积

基于一个简单的非均核链流体分子热力学模型,采用不同形式的微扰项,可构筑不同形式的高分子共混物系统的状态方程。方程已被应用于关联聚苯乙烯/聚2,6-二甲基苯醚(PS/PPO)、聚苯乙烯/聚乙烯甲醚(PS/PVME)、聚苯乙烯/聚丁二烯(PS/PBD)、聚醚砜/聚氧乙烯(PESP/PEO)等高分子共混物的比体积。结果显示,用一个与温度无关的二元相互作用可调参数可满意关联所选体系的比体积,并可预测所选体系的比体积。     

The contribution of implicit cognition to the Theory of Reasoned Action Model: a study of food preferences

Abstract

Attitudes are at the heart of the Theory of Reasoned Action (TRA), but problems in defining and measuring attitudes have contributed to typically low ability to predict behaviour. This article investigates the impact of potential disjuncture between evaluations that an individual externally verbalises (explicit attitudes), and evaluations that are internally held and may exist outside of conscious awareness (implicit attitudes), on the predictive ability of TRA. We study consumers’ attitudes towards eating healthy food and subsequent behaviour in a context of socially consensual behaviour. An Implicit Association Test (IAT) is used to measure implicit attitudes, and these scores are contrasted with self-reported explicit attitude scores. Ninety one participants took part in the study. We found, surprisingly, that implicit attitude has no significant effect on behavioural intention. However, a disjuncture between an individual’s implicit and explicit attitudes, reflecting internal psychological conflict, affected behaviour.     

Simultaneous Estimation of Legal and Illegal Supply and Demand: The Case of Motion Pictures

Prior research into illegal goods has typically looked at one-way effects, such as illegal demand on legal demand. This research investigates a previously unexamined component of the market, illegal supply. The authors examine the supply and demand of legal goods and their illegal counterparts as a market system of four interdependent components. This research makes theoretical and empirical contributions by evaluating illegal supply in this system. Simultaneous equations estimate each market component on the others using data from the motion picture industry. The results find illegal supply has no effect on legal supply (movie screens), positive effects on illegal demand (piracy downloads), and some effect on legal demand (box office revenues). Timing effects highlight this: illegal supply has a positive effect on legal demand during a film’s opening week, but no effect post-launch. The other market components have positive effects on illegal supply (except legal supply, which is negative in the opening week). Additionally, illegal demand has a negative effect on legal demand during the opening week of release, but not in the subsequent weeks. This finding alleviates prior research tension as to whether piracy helps or hurts legal sales, as omitting illegal supply could result in biased estimates.