Contents of heavy metals in arable soils and birth defect risks in Shanxi, China: a small area level geographic study

The burgeoning demands of China’s urbanization and industrial development put pressure on the resources of the entire country and have direct and indirect effects on the health of individuals, at times in areas far removed from cities themselves. Current evidence suggests that heavy metal pollution in soil, a common by-product of coal mining and other industrial activities, may be linked to risk of birth defects. We examine this hypothesis using small area level data including soil samples and detailed birth records from 2002 to 2004 from 97 villages in Shanxi province, a heavy coal-mining region. We find that soils containing arsenic, lead, and nickel are significantly correlated with the incidence of birth defects. In particular, we find a strong positive dose-dependent association of birth defects with lead, a moderate positive effect with arsenic, and a dose-dependent negative association with nickel. These results are consistent with the postulated link between arsenic and lead and human birth defects, but raise questions about the effects of nickel in this context. China’s rapid urbanization underscores the need for closer attention to the relationship between the health and the environment.     

The Process of Familization of Migration in China

China is a transitional and developing country with the largest population and number of farmers in the world, and shows a striking feature of urban-rural dual structure. The major content in China＇s rising modernization is the process of urbanization transformation, urbanization of small and middle-sized city in China should become the basic path selection. Which involves three important issues： concept, people, and institution. Only based on the modernization of concept, people and institution, there will automatically generate the modernization of industry, agriculture, technology and national defense, and thus consistently developing prosperous of both the country and the citizens.     

我国网络课程建设存在的问题及对策

分析指出了我国网络课程建设存在着重申报、轻建设、不持续、更新少、共享难、效果差等问题,提出了课程建设要以学生为主体、课程质量要以学生满意为最终标准,对于目前开展的资源共享课和视频公开课建设,教育行政部门要有顶层设计,要做到网络课程的真正共享,需要从政策层面规范各学科或专业的教学计划、规定学生可以以网络课程完成的科目和学分,学生在规定的教学计划内自由选修网络课程,学分不受地域和学校限制,跨校选修,全国认可;为此网络课程应给与学生自主空间,具有学习过程网络监控、课程考核和学分认证等功能。     

A non-iterative posterior sampling algorithm for linear quantile regression model

In this article, a non-iterative posterior sampling algorithm for linear quantile regression model based on the asymmetric Laplace distribution is proposed. The algorithm combines the inverse Bayes formulae, sampling/importance resampling, and the expectation maximization algorithm to obtain independently and identically distributed samples approximately from the observed posterior distribution, which eliminates the convergence problems in the iterative Gibbs sampling and overcomes the difficulty in evaluating the standard deviance in the EM algorithm. The numeric results in simulations and application to the classical Engel data show that the non-iterative sampling algorithm is more effective than the Gibbs sampling and EM algorithm.     

稳健学生t回归模型变点估计的Gibbs抽样算法

文章讨论了用学生t线性回归模型估计回归系数变点位置的稳健Gibbs抽样算法.利用学生t分布的正态尺度混合表示,得到各参数的满条件后验分布,通过对满条件分布抽取样本,得到变点位置及其他参数的贝叶斯估计.模拟显示该算法能有效地估计变点位置,并且当数据呈现重尾现象时,该模型较正态变点模型要稳健.     

山西沁水煤田东部煤质特征研究

本区含煤地层主要赋存于山西组和太原组，煤层平均总厚13．31m，主要可采煤层煤类为贫煤和无烟煤，具有中灰、中高硫、特低磷、中高热值、热稳定性好等特点，被誉为优质环保煤，是用于发电、采暖及工业锅炉和民用的理想煤类，也是气化和化工的优质原料。     

20世纪20年代的乡土文学状况

20世纪20年代的乡土文学作为乡土文学流派的源头，对乡土文学的发展、流变具有重要的启悟意义。对此一时期的乡土文学研究，概念研究、思想主题研究以及艺术美学研究是研究的中心和重点，对后起的乡土文学创作和评论产生了决定性的影响。     

70年代国外习得顺序研究综述(二)

本文回顾了70年代句子习得顺序的相关研究,主要涉及否定句、疑问句的习得顺序的相关研究,也提及70年代提出的关于关系从句的习得顺序的三大研究假设,最后指出70年代习得顺序研究的意义和不足之处以及之后该领域的主要研究动态。     

中国20世纪现代主义与现代派小说回顾

２０世纪的中国现代主义小说伴随着对外国现代派文学的引进与新文学一起成长，在大陆中断后却在台湾、香港盛极一时，世纪末又在大陆重新出现繁荣。中国现代派小说在成长中形成了与西方现代派小说不全相同的新景观，是２０世纪中国文学的重要收获。     

有效提高远程学习者自主学习的策略

本文通过对远程学习者自主学习的现状分析，提出相应的策略以帮助学员更有效地开展和提高远程自主学习。