论素描的形式美感

素描是造型艺术的基础，同时也是一种独立的艺术形式。素描艺术在反映客观对象的同时，必须运用点、线、面、黑、白、灰这些绘画语言元素表现画面的形式美感。     

Optimal repeated measurements designs for comparing test treatments with a control

A-optimal and mv optimal repeated measurments designs for comparing serveral test treatments with a control are considered. the models considered are basically of two types: without preperides and the cirular model. It is shown known that some known strongly balanced uniform repeated measurements designs can be modified to obtain optimal designs for this problem. Some other methods of finding optimal designs are also given.     

A new special class of peb designs

A new class of partially efficiency-balanced designs is introduced from a practical point of view. This new design includes all equireplicated incomplete block designs available in literature as special cases. The fundamental properties of the design are clarified with relation to other block designs.     

加入WTO对中国上市公司的影响

我国入世以后，各行各业都将经历新的洗礼，证券市场也不例外。尽管由于金融业的特殊性，入世协议允许中国享受一定的待遇和保护性条款，允许存在一定阶段的保护期，但可以预见的是，随着时间的推移，外资将逐步进入中国证券市场，其对中国证券市场上市公司的结构、价值评判体系、行业背景和竞争压力以及监管方式等各方面都将带来深刻的影响，并引导中国的上市公司逐步按照市场化、国际化准则来规范运作。     

Microdata Access and Labor Market Research: The U. S. Experience

Summary: The paper illustrates the value of broad researcher access to survey and administrative microdata using examples drawn from the U. S. experience, outlining how analyses of trends in earnings inequality, poverty and employment dynamics using such data have benefited policy makers and contributed to improvements in statistical agency data products. Methods of facilitating researcher access, including the release of public use files, the use of licensing agreements, and the establishment of research data centers, are discussed. * The author thanks Anne Polivka, Marilyn Seastrom and two anonymous referees for helpful comments on an earlier draft of the paper.     

“The Motherhood Wage Gap for Women in the United States: The Importance of College and Fertility Delay”

One of the stylized facts from the past 30 years has been the declining rate of first births before age 30 for all women and the increase rate of first births after age 30 among women with four-year college degrees (Steven P. Martin, Demography, 37(4), 523–533, 2000). What are some of the factors behind womens decision to postpone their childbearing? We hypothesize that the wage difference often observed between like-educated mothers and non-mothers (Jane Waldfogel, Journal of Labor Economics, 16, 505–545, 1998a; Journal of Economic Perspectives 12(1) 137–156, 1998b) may be affected by the postponement of childbearing until after careers are fully established. Hence, we focus on college-educated women because they are typically more career-oriented than their non-college educated counterparts and also the group most often observed postponing maternity. We use individual-level data on women from the 1979 National Longitudinal Survey of Youth (NLSY79) in order to control for individual-level unobserved heterogeneity as well as human capital characteristics, such as actual work experience, in our empirical analysis. We estimate wage equations, first producing base-line results to compare to the existing literature. Then, we expand the basic wage equation model to address fundamental econometric issues and the education/fertility issue at hand. Our empirical findings are two-fold. First, we find that college-educated mothers do not experience a motherhood wage penalty at all. In fact, they enjoy a wage boost when compared to college-educated childless women. Second, fertility delay enhances this wage boost even further. Our results provide an explanation for the observed postponement of maternity for educated women. We argue that the wage boost experienced by college-educated mothers may be the result of their search for family–friendly work environments, which, in turn, yields job matches with more female-friendly firms offering greater opportunities for advancement.JEL Codes: J13 and J3     

The Relationship Between Wife’s Education and Husband’s Earnings: Evidence from 1960 to 2000

Previous research finds a positive relationship between a wife’s education and her husband’s earnings using data from the 1960s. Earlier theories suggest that benefits accrue from informational sharing between partners in a marriage. This paper tests the hypothesis that a wife’s education is positively associated with her husband’s earnings, using data from the 1960, 1970, 1980, 1990, and 2000 Censuses. Between 1960 and 2000, the educational attainment and labor-force participation of married women has increased dramatically. As women have embarked upon their own careers, has their education continued to be positively associated with their husbands’ earnings? Yes. The coefficient of the wife’s education remains positive and significant for all the years under study. The size of the coefficient decreases, however, from 1960 to 2000.     

幼儿园开展0-3岁早期教育服务指导的现状调查与分析——以陕西省为例

采用问卷法,面向全省范围内的幼儿园及0-3岁婴幼儿家长进行问卷调研,了解已开展过0-3岁早期教育服务指导的幼儿园基本现状,以及幼儿园对于开展0-3岁早期教育服务指导的总体意愿;了解家长在0-3岁早期教育方面的需求及现状。调查分析发现,幼儿园超半数有开展0-3岁早期教育服务指导工作的意愿;幼儿园受家长认可、最突出的优势是“办园规范,值得信赖”;服务指导最主要形式为亲子活动和托班;政策、师资、资金是所需的主要支持。据此建议应及早出台相关具体政策规范幼儿园开展0-3岁早期教育指导服务,幼儿园也应从师资、形式、内容、场地、时间等方面提升专业性、兼顾灵活性以满足家长需求,幼儿园开展0-3岁早期教育指导服务应在先总结典型经验的基础上逐步推广。     

Bernoulli Processes with Non-Positive Correlations

We deal with sequences of dependent Bernoulli variables with non positive correlations. Some special models for 1-dependent and 2-dependent 0–1 valued variables are analyzed, namely Bernoulli variables obtained by clipping a linear combination of iid variables. Formulas describing dependence of their correlation function on the clipping parameters are derived. The lower bound for the sum of autocorrelations of Bernoulli variables obtained by clipping a Gaussian process is provided.