A simulation study of a discrete-time multiserver retrial queue with finite population

In this paper, we deal with a discrete-time multiserver retrial queue with finite population. Firstly, we study the Markov chain at the epochs immediately after slot boundaries making emphasis on the computation of its steady-state distribution. Then, the main performance measures are investigated. Besides, we simulate the waiting time of a customer in the retrial group under three different queueing policies. Some numerical examples are given to illustrate the analysis.     

B股与H股及红筹股之间的溢出效应与信息流动

运用向量GARCH-M模型检验了B股与H股及红筹股之间的溢出效应与信息流动.实证结果表明:红筹股对沪深市B股、H股对沪市B股的收益和波动溢出效应均显著存在,而反向的溢出效应均不显著,表明信息是从红筹股向沪深市B股、从H股向沪市B股单向流动的;深市B股与H股之间相互的收益溢出效应均存在,而波动溢出效应均不存在,信息在H股和深市B股之间的流动情况不明显;在信息流动过程中,红筹股始终处于信息领先地位.     

丙硫咪唑驱绦虫试验

作者首次应用不同剂量的丙硫咪唑进行驱除建鲤绦虫试验。用丙硫咪唑20mg/Kg体重驱除建鲤肠道中的九江头槽绦虫,驱虫率达96.5％以上,效果好,安全可靠。     

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。     

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。     

A method for choosing the smoothing parameter in a semi-parametric model for detecting change-points in blood flow

In a smoothing spline model with unknown change-points, the choice of the smoothing parameter strongly influences the estimation of the change-point locations and the function at the change-points. In a tumor biology example, where change-points in blood flow in response to treatment were of interest, choosing the smoothing parameter based on minimizing generalized cross-validation (GCV) gave unsatisfactory estimates of the change-points. We propose a new method, aGCV, that re-weights the residual sum of squares and generalized degrees of freedom terms from GCV. The weight is chosen to maximize the decrease in the generalized degrees of freedom as a function of the weight value, while simultaneously minimizing aGCV as a function of the smoothing parameter and the change-points. Compared with GCV, simulation studies suggest that the aGCV method yields improved estimates of the change-point and the value of the function at the change-point.     

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。     

Feature screening in ultrahigh-dimensional additive Cox model

The additive Cox model is flexible and powerful for modelling the dynamic changes of regression coefficients in the survival analysis. This paper is concerned with feature screening for the additive Cox model with ultrahigh-dimensional covariates. The proposed screening procedure can effectively identify active predictors. That is, with probability tending to one, the selected variable set includes the actual active predictors. In order to carry out the proposed procedure, we propose an effective algorithm and establish the ascent property of the proposed algorithm. We further prove that the proposed procedure possesses the sure screening property. Furthermore, we examine the finite sample performance of the proposed procedure via Monte Carlo simulations, and illustrate the proposed procedure by a real data example.     

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.