辅酶B_(12)模型化合物n-C_3H_7Co(salen)(γ—pic)的合成和表征

本文用配体置换法合成了烷基钴Schiff碱配合物n—C_3H_ 7Co(salen)(γ—pie)(正丙基·4-甲基吡啶·双水杨醛合乙二亚胺合钴(Ⅱ))。并进行了元素分析、红外光谱、紫外光谱、核磁共振等性质表征。     

Two point priors and Γ-minimax estimating in families of uniform distributions

It is shown that when a parameter lying in a sufficiently small interval is to be estimated in a family of uniform distributions, a two point prior is least favourable under squared error loss. The unique Bayes estimator with respect to this prior is minimax. The Γ-minimax estimator is derived for sets Γ of priors consisting of all priors that give fixed probabilities to two specified subintervals of the parameter space if a two point prior is least favourable in Γ.     

A probablistic analysis for an optimal screening problem

Summary We consider a lotL formed byN apparently similar unitsW ₁,…,W _N, where each of theW _i may come from one of two different populationsP ₁ andP ₂;T ₁,…,T _N denote the corresponding lifetimes. The units fromP _i undergo a failure of kindi and their survival function isS _i (t). We assume that the failure rate function are known and that the units fromP ₁ are ?substandard?: λ ₁ (t)≥λ ₂ (t), ∀t≥0. We want to putW ₁,…,W _N under a pre-operational test (burn-in test) in order to eliminate at least a great part of the substandard units and we face the problem of obtaining a rule for stopping the test under the assumption that, with the failure of a unit, it is possible to recognize the population from which the unit comes. Such a problem will be formalized as an optimal stopping problem for a suitably defined Markov process. Our study shall evidentiate some fundamental aspects of the problem and the role of the prior distribution of the (random) numberM ₀ of those units inL coming fromP ₁ (substandard). The latter distribution has a great influence on the form of the solution. This research was supported by the C.N.R. Project ?Statistica Bayesiana e Simulazione in Affidalità e Modellistica Biologica?.     

Differences in white-nonwhite community mental health center service utilization patterns

Routinely collected computerized data were used to study the process of service delivery in terms of admission patterns, type and quantity of services rendered, and status at termination for whites and nonwhites in two community mental health centers. Social area analysis techniques were employed to control for socio-economic status, ethnicity and life style variables, and an epidemiologic model was used to analyze admission and service delivery rate differences. It was found that nonwhite admission rates were at least twice as great as white rates. Service delivery rates to the population at large were considerably greater for nonwhites than for whites. Delivery of direct services within the centers differed for whites and nonwhites, but no consistent trends emerged when types and amounts of services rendered were analyzed, controlling for sex, ethnicity, age, diagnosis and social area. Disruption of care indices were greater for nonwhites than for whites. Highlighted were some of the complexities involved in interpreting results of utilization studies.     

县级政府、供应链管理与农产品上行关系研究

基于中国13省87个电子商务进农村示范县的调研材料,分析政府项目驱动下农产品上行问题。实践表明,政策利好为县域农产品电商发展提供了试错空间,“S2B2C”的供应链管理模式对农产品上行的推动作用明显。但是,多数县级政府未能认识到供应链管理之于农产品上行的作用,普遍存在政府治理方式滞后、公共服务网络不健全、农产品区域公用品牌缺乏、冷链等基础设施投入不足等问题。因此,为有效推动农产品上行,政府应进一步推动“公私合作”、构建一体化的公共服务、注重品牌营销、优化产品供应链管理。     

非英语专业学生学习策略调查研究——以大学英语分级教学模式下的B级学生为例

通过对50名非英语专业B级学生的实证研究发现,英语学习观念滞后,尤其对学习策略的片面性认识在很大程度上制约了学生英语水平的提高。根据分析结果得出相应的教学启示,以期对提高B级学生的英语综合能力提供有价值的借鉴和参考。     

Meningococcal serogroup B outbreak response University of Wisconsin-Madison

A meningococcal serogroup B (MenB) outbreak at a large public university prompted an emergency response to immunize undergraduates. Objective: To report on a successful meningococcal serogroup B (MenB) vaccine clinic response at a large public university. Methods: We assembled the team leaders to write this case report. Results: Activation of the emergency plan and points of dispensing required cooperation of many units on campus under the leadership of university health officials with support from Centers for Disease Control and Prevention, state division of public health and the city-county health department. Significant efforts to provide consistent messages to students and parents regarding the outbreak and the availability of the MenB vaccines were made. Volunteers were recruited to staff the clinics alongside university healthcare providers. Over 22,000 doses of vaccine were administered. Conclusion: We report our experience and lessons learned which may be helpful to universities in preventing and responding to disease outbreaks.     

Estimation and goodness-of-fit procedures for Farlie–Gumbel–Morgenstern bivariate copula of order statistics

In this study, we provide the Farlie–Gumbel–Morgenstern bivariate copula of rth and sth order statistics. The main emphasis in this study is on the inference procedure which is based on the maximum pseudo-likelihood estimate for the copula parameter. As for the methodology, goodness-of-fit test statistic for copulas which is based on a Cramér–von Mises functional of the empirical copula process is applied for selecting an appropriate model by bootstrapping. An application of the methodology to simulated data set is also presented.     

A Semiparametric Regression Model for Longitudinal Data with Non‐stationary Errors

Motivated by the need to analyze the National Longitudinal Surveys data, we propose a new semiparametric longitudinal mean‐covariance model in which the effects on dependent variable of some explanatory variables are linear and others are non‐linear, while the within‐subject correlations are modelled by a non‐stationary autoregressive error structure. We develop an estimation machinery based on least squares technique by approximating non‐parametric functions via B‐spline expansions and establish the asymptotic normality of parametric estimators as well as the rate of convergence for the non‐parametric estimators. We further advocate a new model selection strategy in the varying‐coefficient model framework, for distinguishing whether a component is significant and subsequently whether it is linear or non‐linear. Besides, the proposed method can also be employed for identifying the true order of lagged terms consistently. Monte Carlo studies are conducted to examine the finite sample performance of our approach, and an application of real data is also illustrated.