重庆区县幼儿家长营养知识、态度、行为的现状及影响因素探析

为了解幼儿家长营养知识、态度、行为的现状，采用问卷调查方法，随机抽取重庆市区县5所幼儿园140名幼儿家长进行调查。幼儿家长的营养知识、态度、行为的总体情况良好。幼儿家长的营养知识、态度和行为受到亲缘关系、文化程度和职业等因素不同程度的影响，且存在显著差异。幼儿家长营养知识、态度及行为有待进一步提高。幼儿园应该实行多种途径的营养教育，包括针对幼儿家长进行教育，同时尽早将营养知识纳人幼儿园的教育内容，使家庭和幼儿园一起来维护幼儿的身体健康。     

Housing hardship and energy insecurity among native-born and immigrant low-income families with children in the United States

The costs for rent and utilities account for the largest share of living expenses, yet these two critical dimensions of material hardship have seldom been examined concurrently in population-based studies. This paper employs multivariate statistical analysis using American Community Survey data to demonstrate the relative risk ratio of low-income renter-occupied households with children experiencing ‘rent burden', ‘energy insecurity', or a ‘double burden’ as opposed to no burden. Findings suggest that low-income households are more likely to experience these economic hardships in general but that specific groups are disproportionately burdened in different ways. For instance, whereas immigrants are more likely to experience rental burden, they are less likely to experience energy insecurity and are also spared from the double burden. In contrast, native-born African Americans are more likely than all other groups to experience the double burden. These results may be driven by the housing stock available to certain groups due to racial residential segregation, decisions regarding the quality of housing low-income householders are able to afford, as well as home-country values, such as modest living and energy conservation practices, among immigrant families. This paper also points to important policy gaps in safety net benefits related to housing and energy targeting low-income households.     

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.     

基于ANSYS的压力容器表面凹坑缺陷安全评定分析

采用通用有限元程序ANSYS建立了移动式压力容器筒体外壁表面凹坑（轴向和周向）的有限元模型。结合筒体表面凹坑的应力理论计算，研究探讨了在恒定内压下，筒体表面凹坑缺陷处的应力分布与凹坑几何尺寸之间的关系。以第三强度理论作为仿真终止判据，获取凹坑各几何参量的阈值，利用MATLAB对阈值进行最小二乘拟合，绘制出凹坑缺陷的安全评估参考曲线。拟合结果表明：轴向和周向凹坑对筒体局部结构强度的影响不同，对应的安全评估参考曲线存在区别。     

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。