实数域及四元数除环上有平方根的方阵

给出了实数域及实四元数除环上方阵有平方根的充分必要条件．     

Effects of Medicaid managed care policies on mental health service use among a national probability sample of children in the child welfare system

Children in the child welfare system are dependent upon Medicaid to finance services for their considerable mental health needs. This study examines the effects of Medicaid policies on mental health service use among a national probability sample of children in the child welfare system. Data for this study came from the National Survey of Child and Adolescent Well-Being, the Caring for Children in Child Welfare study, and the Area Resource File. Weighted multivariate logistic regression analyses were conducted to estimate effects of policy variables on children's use of mental health services, controlling for child-level covariates and county-level health resources. Children in counties with behavioral carve-outs under Medicaid managed care had lower odds of inpatient mental health service use. Medicaid managed care enrollment and variations in type of provider reimbursement did not affect use of mental health services. Older age, greater need for mental health services, and higher levels of caregiver education were associated with increased odds of service use. Restrictions on use of inpatient mental healthcare caused by behavioral carve-outs may disproportionately affect children in the child welfare system who have high rates of such use. Careful adoption of carve-outs is necessary to assure appropriate care for these children.     

“与贸易有关的投资措施”经济学分析

通过文献梳理发现,作为有益于东道国发展的政策,与贸易有关的投资措施对东道国经济发展的作用因不同国家和不同市场条件而异.东道国特别是发展中国家应该高度重视与贸易有关的投资措施研究,并采用相应的外资政策.     

美国与英国公益性科技管理体系研究

从国家科技管理机构、科研体系及公共科研成果转化三个方面分析美国和英国的公益性科技管理制度及其发展变化.随着经济全球化和知识自由流动的发展,科学技术在国家经济发展与社会进步方面的作用越来越大,政府在科技管理上的职能与地位也随之发生变化,总的来说是由原来的主要资助者和实施者转变为催化者和促进者.     

Family Cap and Nonmarital Fertility: The Racial Conditioning of Policy Effects

Using an experimental design, this research examines the effect of the nation's first family cap on the births, abortions, and contraception use of over 8,000 women receiving public assistance in New Jersey. The family cap denies additional cash benefits to children conceived while the mother is receiving public assistance. Our research shows that a targeted welfare benefit manipulation does influence fertility behavior; however, the effect is conditioned by race. We find that Black women in the experimental group have a 21% lower birth rate and a 32% higher abortion rate than Black women in the control group. We do not find a birth effect for Hispanic or White women. We discuss the policy implications of the effects of a segmented family cap.     

Uncertainty Analysis for Computer Model Projections of Hurricane Losses

Projecting losses associated with hurricanes is a complex and difficult undertaking that is wrought with uncertainties. Hurricane Charley, which struck southwest Florida on August 13, 2004, illustrates the uncertainty of forecasting damages from these storms. Due to shifts in the track and the rapid intensification of the storm, real-time estimates grew from 2 to 3 billion dollars in losses late on August 12 to a peak of 50 billion dollars for a brief time as the storm appeared to be headed for the Tampa Bay area. The storm hit the resort areas of Charlotte Harbor near Punta Gorda and then went on to Orlando in the central part of the state, with early poststorm estimates converging on a damage estimate in the 28 to 31 billion dollars range. Comparable damage to central Florida had not been seen since Hurricane Donna in 1960. The Florida Commission on Hurricane Loss Projection Methodology (FCHLPM) has recognized the role of computer models in projecting losses from hurricanes. The FCHLPM established a professional team to perform onsite (confidential) audits of computer models developed by several different companies in the United States that seek to have their models approved for use in insurance rate filings in Florida. The team's members represent the fields of actuarial science, computer science, meteorology, statistics, and wind and structural engineering. An important part of the auditing process requires uncertainty and sensitivity analyses to be performed with the applicant's proprietary model. To influence future such analyses, an uncertainty and sensitivity analysis has been completed for loss projections arising from use of a Holland B parameter hurricane wind field model. Uncertainty analysis quantifies the expected percentage reduction in the uncertainty of wind speed and loss that is attributable to each of the input variables.     

福利多元主义视角下的社区福利

随着经济体制的改革,“单位人”向“社区人”转变,社区福利成为社会成员普遍性的需求。但目前我国的社区福利存在着行政化、非专业化等一系列问题,社区内缺少成熟的、有活力的社会团体,严重影响了社区居民对于福利的可及性和可得性。本文尝试从福利多元主义的视角,在福利服务领域引入非营利组织,并重点讨论政府的角色转变以及与这些志愿组织和社会团体的合作关系。     

欧洲一体化进程中的社会福利整合

欧洲一体化是一个经济、政治和文化不断融合的过程。欧盟从建立之初就开始了劳工政策领域的合作,随着区域经济合作加强、移民增加、劳动力市场一体化,各国社会保障制度之间的差异就成了迫切需要解决的问题。社会保障方面的合作越来越受到重视,合作的范围逐渐扩大到促进就业、失业保障、养老保障、医疗和公共卫生等领域,虽然至今还没有欧盟统一层面的社会保障政策出台,但在某些方面已经出现了趋同倾向。     

On Block Updating in Markov Random Field Models for Disease Mapping

Gaussian Markov random field (GMRF) models are commonly used to model spatial correlation in disease mapping applications. For Bayesian inference by MCMC, so far mainly single-site updating algorithms have been considered. However, convergence and mixing properties of such algorithms can be extremely poor due to strong dependencies of parameters in the posterior distribution. In this paper, we propose various block sampling algorithms in order to improve the MCMC performance. The methodology is rather general, allows for non-standard full conditionals, and can be applied in a modular fashion in a large number of different scenarios. For illustration we consider three different applications: two formulations for spatial modelling of a single disease (with and without additional unstructured parameters respectively), and one formulation for the joint analysis of two diseases. The results indicate that the largest benefits are obtained if parameters and the corresponding hyperparameter are updated jointly in one large block. Implementation of such block algorithms is relatively easy using methods for fast sampling of Gaussian Markov random fields ( Rue, 2001 ). By comparison, Monte Carlo estimates based on single-site updating can be rather misleading, even for very long runs. Our results may have wider relevance for efficient MCMC simulation in hierarchical models with Markov random field components.     

三维Minkowski空间中有相等主曲率函数的一类特殊曲面的位置向量场

讨论三维Minkowski空间R2 .1中一类特殊曲面在主曲率函数相等时的情形 ,给出了这类曲面在这一情形下的位置向量场