切实加快城市化发展步伐是解决结构性矛盾与"三农"问题的关键

城市化是一种具有普遍性和带有规律性的经济社会发展趋势.我国由于城市化水平低,城乡结构不合理,使得供求、产业、就业、地区经济差距等结构性矛盾非常明显,"三农"即农民、农村、农业问题日益突出.这些矛盾和问题的解决,必须从思想观念、政策、方法等方面有所突破,切实加快城市化发展步伐.     

结构调整:理论一般与中国的特殊

结构调整是中国21世纪初所面临的难题.从理论上看,结构矛盾是由市场的不完全性造成的;从实际情况看,中国的结构矛盾又有特殊性,包括传统体制留下的结构矛盾"存量"大、经济增长速度快、二元经济结构矛盾严重等.中国的结构调整必须从弥补市场的不完全性入手,重视发挥市场的作用.政府除了引导经济结构向信息化、高技术化方向发展之外,重点可放在培育市场机制,维护市场秩序;培育企业家队伍;缩小收入差距;以需求和优势为基础选择产业方向;以产业转移成本为标准选择产业转移模式等方面.     

An Empirical Test of Competing Theories of Hazard-Related Trust: The Case of GM Food

Few scholars doubt the importance of trust in explaining variation in public perception of technological risk. Relatively little, however, is known about the particular types of judgments that people use in granting or withholding trust. This article presents findings from an empirical study that explores several dimensions of trust relevant for citizens' judgments of scientists involved in the development of GM food. The relationship between particular dimensions of trust and perceptions of GM food risk is also explored, using structural equation modeling. Results suggest that trust judgments based on the perception of shared values are most important in relation to GM food risk, but that judgments about scientists' technical competence are also important.     

Admissible minimum bias estimation of response surfaces

The minimum bias estimator was introduced as an alternative to the least squares estimator for approximating response functions by low-order polynomials. Here we show how to obtain an admissible estimator with smaller squared bias.     

Second-Order Response Surface Model with Neighbor Effects

This article considers the second-order response surface model in which the experimental units, i.e., plots experience the neighbor effects from immediate left and right neighboring plots assuming the plots to be placed adjacent linearly with no gaps. Conditions have been derived for the estimation of coefficients of second-order response surface model. A method of constructing designs for fitting second-order response surface in the presence of neighbor effects has been developed. The designs so obtained are found to be rotatable.     

弯曲液面的临界光反射现象

实验中发现了弯曲液面的临界光反射现象,并采集到清晰的、对比度高的弯曲液面临界反射图样。在激光束斜入射的情况下,弯曲液面临界反射的图样中,有一椭圆状暗场,暗场附近区域有明亮清晰的条纹。根据几何光学的分析,解释了这一临界光反射现象。     

双曲率面光线追迹公式及应用

本文提出了用牛顿迭代法计算光线与双曲率面的交点,并给出了具体的计算公式。文中还认为可以利用双曲率面来描述存在着局部变形的球面光学零件,为制定光学零件的公差提供了依据。     

心理词汇结构表征与二语产出性词汇能力发展

母语心理词汇结构表征与二语心理词汇结构表征存在差异。母语心理词汇中词与词是以语义为联系的,而二语心理词汇中词与词的联系是语音起主要作用。学习者的二语产出性词汇能力到了某一阶段后出现"停滞现象",因此,为促进二语产出性词汇能力的发展,二语学习者有必要重组二语心理词汇结构并加深对单词的语义理解,不断地积累该词与其他词的语义联系。     

Optimal choice of sample fraction in univariate financial tail index estimation

This study introduces a technique to estimate the Pareto distribution of the stock exchange index by using the maximum-likelihood Hill estimator. Recursive procedures based on the goodness-of-fit statistics are used to determine the optimal threshold fraction of extreme values to be included in tail estimation. These procedures are applied to three indices in the Malaysian stock market which included the consideration of a drastic economic event such as the Asian financial crisis. The empirical results evidenced alternating varying behavior of heavy-tailed distributions in the regimes for both upper and lower tails.