德国食品卫生法律制度刍议

德国作为世界四大食品出口国之一,食品出口额在欧洲一直稳居榜首.其最主要的原因要归于业界对德国食品质量有口皆碑的赞誉,隐匿其后的则是德国健全的食品卫生法律制度居功厥伟的作用.无论是其食品卫生法律制度体系架构的严密性,还是具体操作层面的诸多实施方式都颇具借鉴意义.     

Estimation with right‐censored observations under a semi‐Markov model

The semi‐Markov process often provides a better framework than the classical Markov process for the analysis of events with multiple states. The purpose of this paper is twofold. First, we show that in the presence of right censoring, when the right end‐point of the support of the censoring time is strictly less than the right end‐point of the support of the semi‐Markov kernel, the transition probability of the semi‐Markov process is nonidentifiable, and the estimators proposed in the literature are inconsistent in general. We derive the set of all attainable values for the transition probability based on the censored data, and we propose a nonparametric inference procedure for the transition probability using this set. Second, the conventional approach to constructing confidence bands is not applicable for the semi‐Markov kernel and the sojourn time distribution. We propose new perturbation resampling methods to construct these confidence bands. Different weights and transformations are explored in the construction. We use simulation to examine our proposals and illustrate them with hospitalization data from a recent cancer survivor study. The Canadian Journal of Statistics 41: 237–256; 2013 © 2013 Statistical Society of Canada     

Prediction based classification for longitudinal biomarkers

Assessment of circulating CD4 count change over time in HIV-infected subjects on antiretroviral therapy (ART) is a central component of disease monitoring. The increasing number of HIV-infected subjects starting therapy and the limited capacity to support CD4 count testing within resource-limited settings have fueled interest in identifying correlates of CD4 count change such as total lymphocyte count, among others. The application of modeling techniques will be essential to this endeavor due to the typically non-linear CD4 trajectory over time and the multiple input variables necessary for capturing CD4 variability. We propose a prediction based classification approach that involves first stage modeling and subsequent classification based on clinically meaningful thresholds. This approach draws on existing analytical methods described in the receiver operating characteristic curve literature while presenting an extension for handling a continuous outcome. Application of this method to an independent test sample results in greater than 98% positive predictive value for CD4 count change. The prediction algorithm is derived based on a cohort of n = 270 HIV-1 infected individuals from the Royal Free Hospital, London who were followed for up to three years from initiation of ART. A test sample comprised of n = 72 individuals from Philadelphia and followed for a similar length of time is used for validation. Results suggest that this approach may be a useful tool for prioritizing limited laboratory resources for CD4 testing after subjects start antiretroviral therapy.     

SPECIAL ISSUE： REGIONAL CONVERGENCE AND COORDINATED URBAN GROWTH Externalities, Transport Networks and the Economic Growth of Urban Clusters

利用网络分析工具和新经济地理理论对新古典区域经济增长模型进行修正，通过对交易费用的细分构建外部性和运输网络下的城市群经济增长模型，并利用1990-2008年中国部分城市数据和向量自回归模型（VAR）进行实证检验，得出以下结论。在运输网络影响下，中心城市依靠要素集聚获得增长，非中心城市快速接近中心城市。运输网络的改善，将加速中心城市的要素集聚。同时，在保留部分新增要素的情况下，增加节点集聚系数、降低非中心城市问的运输成本，利于非中心城市对外部性的应用，加速其经济增长，促进与中心城市的协同增长。因此，在建设交通运输基础设施时，不仅要重视非中心城市与中心城市的互联互通，更要重视非中心城市间的相互联结。     

试论在高师院校《实变函数》教学中引入现代数学思想的必要性及可能的途径

阐述了在高师院校实变函数教学中引入现代数学思想的必要性 ;指出目前在实变函数教学中较系统和全面地介绍分形的数学思想和应用是一个非常好的课题 ,并给出了具体的理由和可供操作的可能途径     

Pseudolikelihood estimation in a class of problems with response-related missing covariates

Many practical situations involve a response variable Y and covariates X , where data on (Y, X ) are incomplete for some portion of a sample of individuals. We consider two general types of pseudolikelihood estimation for problems in which missingness may be response-related. These are typically simpler to implement than ordinary maximum likelihood, which in this context is semiparametric. Asymptotics for the pseudolikelihood methods are presented, and simulations conducted to investigate the methods for an important class of problems involving lifetime data. Our results indicate that for these problems the two methods are effective and comparable with respect to efficiency.     

义和团运动与晚清漕粮运输

义和团运动对晚清的漕粮运输产生了重大影响.首先,义和团运动爆发后,八国联军侵华,占领津京等地区,慈禧太后挟光绪帝出逃,导致漕粮海运中断,并转而将部分漕粮向山西、陕西运送.其次.义和团运动被镇压后,朝廷被迫与联军签定<辛丑条约>,偿付巨额赔款,清朝的财政体系完全崩溃.为筹措赔款,清廷不得不颁布"漕粮改折诏".虽然江浙后来又恢复本色100万石,但漕运制度已经遭到致命打击.再次,为节省费用,清廷开始采纳铁路剥漕的方式,结果成为继轮船之后,漕粮运输工具史上的又一重大突破.简言之,义和团运动是晚清漕粮运输的转折点.     

关于广义远达问题的适定性(英文)

设C是实Banach空间X中有界闭凸子集且0是C的内点,PC(·)是关于C的Minkowski泛函.设K是Banach空间X中非空闭的有界相对弱紧子集.对X中的点x,称最大化问题maxC( x,K)为适定的是指存在唯一的-z∈ K使得pC(z- -x)= uC( x,K)和每一满足li mn→∞pC(zn-x) = uC( x,K)的序列{zn} K均强收敛到z-,其中uC( x,K) =supz∈KpC(z -x) .在C是严格凸和Kadec的假定下,证得了使得最大化问题maxC( x,k)为适定的所有x∈ X的全体组成的集合X0( K)是X中的剩余集.进一步,如果关于pC(·)的凸性模是严格正的,K是X中闭的有界子集,证明了集X\X0( K)是X中的σ-多孔集.这些本质地推广和延拓了包括De Blasi等,Fitzpatrick,Panda和Kapoor ,Li和作者等人结果在内的近期相应结果.