线性矩阵不等式问题的进化计算解决方法

针对决定模糊控制中稳定性的线性矩阵不等式问题,提出了用进化计算来解决模糊控制中线性矩阵不等式的新算法。实验证明,该算法解“用于实现模糊控制的增益调度和稳定性的线性矩阵不等式”是有效的。     

21世纪高校图书馆的读者服务

本文从职业道德、业务素质、服务方式三个方面讨论高校图书馆的读者服务工作。提出了如何加强职业道德建设，提高图书馆员业务素质，更新信息服务方式。     

Dose-Response and Risk Assessment of Airborne Hexavalent Chromium and Lung Cancer Mortality

This study evaluates the dose-response relationship for inhalation exposure to hexavalent chromium [Cr(VI)] and lung cancer mortality for workers of a chromate production facility, and provides estimates of the carcinogenic potency. The data were analyzed using relative risk and additive risk dose-response models implemented with both Poisson and Cox regression. Potential confounding by birth cohort and smoking prevalence were also assessed. Lifetime cumulative exposure and highest monthly exposure were the dose metrics evaluated. The estimated lifetime additional risk of lung cancer mortality associated with 45 years of occupational exposure to 1 microg/m3 Cr(VI) (occupational exposure unit risk) was 0.00205 (90%CI: 0.00134, 0.00291) for the relative risk model and 0.00216 (90%CI: 0.00143, 0.00302) for the additive risk model assuming a linear dose response for cumulative exposure with a five-year lag. Extrapolating these findings to a continuous (e.g., environmental) exposure scenario yielded an environmental unit risk of 0.00978 (90%CI: 0.00640, 0.0138) for the relative risk model [e.g., a cancer slope factor of 34 (mg/kg-day)-1] and 0.0125 (90%CI: 0.00833, 0.0175) for the additive risk model. The relative risk model is preferred because it is more consistent with the expected trend for lung cancer risk with age. Based on statistical tests for exposure-related trend, there was no statistically significant increased lung cancer risk below lifetime cumulative occupational exposures of 1.0 mg-yr/m3, and no excess risk for workers whose highest average monthly exposure did not exceed the current Permissible Exposure Limit (52 microg/m3). It is acknowledged that this study had limited power to detect increases at these low exposure levels. These cancer potency estimates are comparable to those developed by U.S. regulatory agencies and should be useful for assessing the potential cancer hazard associated with inhaled Cr(VI).     

从职业流动看失业阻滞与再就业机制

从职业流动视角来看 ,失业具有无流动性、下向流动性和被迫性 ;失业阻滞在于职业流动的规模不大 ,制度约束性太强和观念滞后 ;再就业具有上向流动性和主动性 ;再就业机制是一个由经济驱动机制、制度改革机制、就业观念转变机制和劳动力自由流动机制构成的综合性、动态性结构体系。     

重塑大学生就业观

随着我国高等教育事业的发展 ,高校的不断扩招 ,就业形势越来越严峻。“先就业 ,后择业 ,再创业”的择业观为各高校所倡行 ,但这种择业观中隐含了不少弊病。从目前我国高校就业形势来看我们认为应当从社会要求、诚信教育、职业理想及规划等方面对学生进行引导和教育 ,在此基础上秉承“先择业 ,后就业 ,再择岗”的择业观 ,才比较符合现实。     

Exposure Reconstruction for the TCDD-Exposed NIOSH Cohort Using a Concentration- and Age-Dependent Model of Elimination

Recent studies demonstrating a concentration dependence of elimination of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) suggest that previous estimates of exposure for occupationally exposed cohorts may have underestimated actual exposure, resulting in a potential overestimate of the carcinogenic potency of TCDD in humans based on the mortality data for these cohorts. Using a database on U.S. chemical manufacturing workers potentially exposed to TCDD compiled by the National Institute for Occupational Safety and Health (NIOSH), we evaluated the impact of using a concentration- and age-dependent elimination model (CADM) (Aylward et al., 2005) on estimates of serum lipid area under the curve (AUC) for the NIOSH cohort. These data were used previously by Steenland et al. (2001) in combination with a first-order elimination model with an 8.7-year half-life to estimate cumulative serum lipid concentration (equivalent to AUC) for these workers for use in cancer dose-response assessment. Serum lipid TCDD measurements taken in 1988 for a subset of the cohort were combined with the NIOSH job exposure matrix and work histories to estimate dose rates per unit of exposure score. We evaluated the effect of choices in regression model (regression on untransformed vs. ln-transformed data and inclusion of a nonzero regression intercept) as well as the impact of choices of elimination models and parameters on estimated AUCs for the cohort. Central estimates for dose rate parameters derived from the serum-sampled subcohort were applied with the elimination models to time-specific exposure scores for the entire cohort to generate AUC estimates for all cohort members. Use of the CADM resulted in improved model fits to the serum sampling data compared to the first-order models. Dose rates varied by a factor of 50 among different combinations of elimination model, parameter sets, and regression models. Use of a CADM results in increases of up to five-fold in AUC estimates for the more highly exposed members of the cohort compared to estimates obtained using the first-order model with 8.7-year half-life. This degree of variation in the AUC estimates for this cohort would affect substantially the cancer potency estimates derived from the mortality data from this cohort. Such variability and uncertainty in the reconstructed serum lipid AUC estimates for this cohort, depending on elimination model, parameter set, and regression model, have not been described previously and are critical components in evaluating the dose-response data from the occupationally exposed populations.     

教师社会幸福感现状及提升策略--基于全国33590名中小学教师的调查与分析

教师社会幸福感影响教师总体的职业幸福感。为揭示教师社会幸福感的整体状况及其在领导关系、同事关系、师生关系、家校关系、社会声誉等维度上的具体表现,在全国范围内,对东部、中部、西部、东北等4个地区的33590名中小学教师的社会幸福感现状进行问卷调查。调查结果显示:教师社会幸福感总体水平较高,但在性别、地区、教龄等方面存在差异。要进一步增强教师社会幸福感,应着力改善教师与领导关系和师生关系;满足教师的物质需求和发展需求,切实提升教师社会声誉;考虑个体差异,制定具有针对性的教师社会幸福感提升策略;改进教师职前教育和在职教育,提升教师获得社会幸福感的能力。     

中国企业年金缴费率的模拟分析

企业年金在多支柱养老保险体系中发挥着越来越重要的作用.以个人账户为研究对象,为我国企业年金建立了精算平衡模型.文章在精算平衡模型的基础上,运用模拟的方法,对企业年金的缴费率进行了测算分析.并根据模拟的结果,对2004年5月1日开始实施的<企业年金试行办法>中缴费率的规定进行了讨论,为企业年金的发展和政策制定提供了建议.     

Strong law of large numbers and complete convergence for non-identically distributed WOD random variables

In this paper, we establish the strong law of large numbers and complete convergence for non-identically distributed WOD random variables. We derive some new inequalities of Fuk–Nagaev type for the sums of non-identically distributed WD random variables. All these results further extend and refine previous ones.     

Addressing inequality: Educators responding to the contexts of young children’s lives?

A child's early relationships and experiences influence their long-term development and learning. In Australia, some children can face complex levels of deprivation when compared to their peers. This study sheds light on how educators are responding. Data analysed consist of individual interviews with early childhood educators working in diverse communities. The findings highlight educators’ accounts of responsiveness as narrowly framed with attention focused on children's cultural heritage which overshadows other equity groups. The paper argues that by becoming sensitive to the contexts of children's lives, there is potential to build the early childhood workforce's capacity for addressing inequalities in childhood.