中国木犀属小志

In the present paper a new species, Osmanthus gracilinervis Chia ex R. L. Lu, is described from Guangxi.  The new species is also distributed in Guangdong, Jiangxi, Zhejiang, Hunan and Sichuan.  Based on the analysis of a great deal of specimens, eight spe- cies, i.e. Osmanthus corymbosus H. W. Li, O. longispermus H. T. Chang, O. angustifolius H. T. Chang, O. triandrus H. T. Chang, O. longicarpus H. T. Chang, O. omeiensis Fang ex H. T. Chang, O. nanchuanensis H. T. Chang and 0. cylindricus H. T. Chang, are reduced as the synonyms of O. marginatus (Champ. ex Benth.)  Hemsl. var. marginatus. O. longissimus H. T. Chang and O. pachyphyllus H. T. Chang are respectively reduced to varieties of O. marginatus, i.e.O.  marginatus var. longissimus (H.T. Chang) R. L. Lu and var. pachy- phyllus (H. T.Chang) R. L. Lu.  And finally O. maximus H. T. Chang is treated in this paper as a synonym of O. matsumuranus Hayata.     

美国国家标准职业分类系统的发展概况及对我国的启示

本文主要介绍了美国国家的职业分类系统的现状，回顾了美国国家标准的职业分类系统的发展历史、修订原则和方法，新职业分类系统的特点以及用途，以及在建立美国国家通用的标准职业信息系统时所作的努力。最后，本文结合美国职业分类系统的经验，提出《中华人民共和国职业分类大典》的修订工作应广泛征求修订意见，邀请社会各界参与；重视科学统一的职业分类标准的制定；加强职业分类实证资料的收集；积极采取有效措施，以保证职业分类系统的持续更新。     

Poisoning the mind: Arsenic contamination of drinking water wells and children's educational achievement in rural Bangladesh

Bangladesh has experienced the largest mass poisoning of a population in history owing to contamination of groundwater with naturally occurring inorganic arsenic. Prolonged drinking of such water risks development of diseases and therefore has implications for children's cognitive and psychological development. This study examines the effect of arsenic contamination of tubewells, the primary source of drinking water at home, on the learning outcome of school-going children in rural Bangladesh using recent nationally representative data on secondary school children. We unambiguously find a negative and statistically significant correlation between mathematics scores and arsenic-contaminated drinking tubewells at home, net of the child's socio-economic status, parental background and school specific unobserved correlates of learning. Similar correlations are found for an alternative measure of student achievement and subjective well-being (i.e. self-reported measure of life satisfaction), of the student. We conclude by discussing the policy implication of our findings in the context of the current debate over the adverse effect of arsenic poisoning on children.     

Educational gaps in medical care and health behavior: Evidence from US Natality data

The US Natality files provide information on medical procedures and health related behavior during pregnancy and childbirth. The data set represents nearly the universe of mothers who give birth in the US, providing the most complete coverage possible of medical care and health behavior among a specific patient population. We document gaps in outcomes by education of the mother and the changes in these educational gaps during 1989-2002.     

The quality vs. the quantity of schooling: What drives economic growth?

This paper challenges Hanushek and Woessmann's (2008) contention that the quality and not the quantity of schooling determines a nation's rate of economic growth. I first show that their statistical analysis is flawed. I then show that when a nation's average test scores and average schooling attainment are included in a national income model, both measures explain income differences, but schooling attainment has greater statistical significance. The high correlation between a nation's average schooling attainment, cumulative investment in schooling, and average tests scores indicates that average schooling attainment implicitly measures the quality as well as the quantity of schooling.     

The impact of child labor on schooling outcomes in Nicaragua

Child labor is considered a key obstacle to reaching the international commitments of Education For All. However, the empirical evidence on the effects of child labor on educational attainments is mostly limited to static measurements. This paper assesses the consequences of child labor on schooling outcomes over time by employing a three-year longitudinal household data set from Nicaragua. The potential endogeneity of past child labor and school outcomes is addressed through instrumental variables. The time a child dedicates to work is found to have harmful consequences on subsequent educational achievements, even after controlling for previous human capital accumulation and other factors. In particular, working over three hours a day is associated with school failure in the medium term. A distinction by type of work shows that time spent in market production has larger negative effects on school outcomes than time spent performing household chores.     

前躯体煅烧法制备Cr2O3微/纳米球

采用前躯体煅烧法制备了无机微/纳米材料Cr2O3.利用有机碱的缓慢水解,用无机盐铬源,在水和乙醇或者其他混合溶剂中进行水热反应,首先制得前躯体Cr（OH）3,然后通过煅烧得到Cr2O3微/纳米粒子.通过对比实验,发现影响前躯体和最终产物尺寸大小的主要因素是所使用的有机碱（沉淀剂）的种类.对前躯体采用红外光谱（IR）和热重分析（TG）进行了表征,对产物采用X-射线粉末衍射（XRD）、扫描电镜（SEM）和透射电镜（TEM）进行了表征.     

Conveying quality and value in emerging industries: Star scientists and the role of signals in biotechnology

This paper addresses the role that scientific status plays in initial public offerings of technology focused firms. The paper builds on the literature of the sociology of science as well as the work of Spence (1974) and Podolny (1993) and argues that the presence of a Nobel laureate affiliated with a firm making an IPO provides a signal of firm quality to potential investors. Moreover, and building on the work of Podolny and Scott Morton (1999) and Stuart et al. (1999) we hypothesize that the importance of status diminishes as other measures of firm quality become available. We test our hypothesis for two periods of initial public offerings in biotechnology. We document that there is a clear difference in “maturity” of the firms across the two windows on a number of metrics. Consistent with our hypothesis that Nobel laureates play an important role as a non-financial signal of firm quality, we find that first-window firms with a Nobel laureate affiliate realize greater IPO proceeds in the amount of $24 million. In the second window the amount of money raised is not significantly different between Nobel and non-Nobel firms. This finding is consistent with the signaling literature that argues that the importance of a signal is inversely related to the availability of cogent information on firm quality. Consistent with this view, we also find a change between the two windows in the importance of other non-financial metrics used to convey value. Our research is one of the first to examine the dynamic nature of signals. Because we are unable to distinguish the extent to which the reduction in uncertainty at the firm level is correlated with the reduction of uncertainty at the industry level, the question remains as to the extent to which the diminished importance of signals in our second period is due to a change in market uncertainty versus a change in firm uncertainty.