Logistic regression analysis of randomized response data with missing covariates

Randomized response is an interview technique designed to eliminate response bias when sensitive questions are asked. In this paper, we present a logistic regression model on randomized response data when the covariates on some subjects are missing at random. In particular, we propose Horvitz and Thompson (1952)-type weighted estimators by using different estimates of the selection probabilities. We present large sample theory for the proposed estimators and show that they are more efficient than the estimator using the true selection probabilities. Simulation results support theoretical analysis. We also illustrate the approach using data from a survey of cable TV.     

荧光假单胞菌BIT-18磷脂酶B基因的克隆及生物信息学分析

利用PCR从Pseudomonas fluorescens BIT-18总DNA中成功扩增到编码Pf-PLB的全长基因,并进行测序.通过生物信息学分析,可知Pf-PLB基因全长1272 bp,编码423个氨基酸,理论分子量为45.8kDa,等电点为5.53,在N末端有一个包含23个氨基酸的信号肽.进化树及序列分析结果显示,pfplb是PLBs新基因家族的成员.采用模建软件Modeller进行人工建模,结果表明Pf-PLB为由14股Strand组成的β-桶状蛋白,本研究为Pf-PLB进一步高效表达及其脱胶机理研究奠定基础.     

检察机关如何改进执法方式为经济社会发展服务

检察机关进一步改进执法方式服务经济社会发展,需要科学正确的执法理念支撑,需要恰当合理的工作态度定位,需要人文理性的工作模式推动,需要扎实有效的机制约束保障。     

Nonparametric estimation of the bivariate survival function with left-truncated and right-censored data

In this note, we consider estimating the bivariate survival function when both components are subject to left truncation and right censoring. We propose two types of estimators as generalizations of the Dabrowska and Campbell and Földes estimators. The consistency of the proposed estimators is established. A simple bootstrap method is used for obtaining precision estimation of the proposed estimators. A simulation study is conducted to investigate the performance of the proposed estimators.     

Fostering integrative community leadership

This longitudinal field study examined the determinants of integrative, volunteer community leadership. Using a sample of 1443 participants in 43 community leadership programs across North America, we linked altruistic, social- and self-oriented motives to the breadth of individuals' volunteer involvement in their communities. Individuals who engaged in volunteer community leadership reported more altruistic motives (i.e., they volunteered because they were concerned about others). High levels of voluntary community leadership were also associated with social motives, such as getting involved in the community because friends or important others think doing so is important. Regardless of their motives, participants engaged in their communities in new ways following participation in a community leadership program, suggesting that such programs foster integrative community leadership. Programs that focused on team building as part of their curriculum were the most successful in fostering new community leadership activities, and programs that focused on knowledge and awareness of the community were effective in increasing participants' knowledge and awareness of the community. Considered as a whole, results of this study suggest that community leadership programs can increase both knowledge and awareness of the community and actual engagement in the community for community members who choose to participate in such programs.     

Efficient mean estimation in log-normal linear models

Log-normal linear models are widely used in applications, and many times it is of interest to predict the response variable or to estimate the mean of the response variable at the original scale for a new set of covariate values. In this paper we consider the problem of efficient estimation of the conditional mean of the response variable at the original scale for log-normal linear models. Several existing estimators are reviewed first, including the maximum likelihood (ML) estimator, the restricted ML (REML) estimator, the uniformly minimum variance unbiased (UMVU) estimator, and a bias-corrected REML estimator. We then propose two estimators that minimize the asymptotic mean squared error and the asymptotic bias, respectively. A parametric bootstrap procedure is also described to obtain confidence intervals for the proposed estimators. Both the new estimators and the bootstrap procedure are very easy to implement. Comparisons of the estimators using simulation studies suggest that our estimators perform better than the existing ones, and the bootstrap procedure yields confidence intervals with good coverage properties. A real application of estimating the mean sediment discharge is used to illustrate the methodology.     

Giving Back and Staying Put: Volunteering as a Stabilizing Force in Relocation

Relocation in older adulthood has been shown to have health-related and environmental triggering factors. This study explores the relationship between volunteering in a community and relocation. Using data from the 2008 and 2010 Health and Retirement Study, which included 9,220 community-dwelling older individuals who were aged 65 years and older, our findings show that volunteering significantly reduces the likelihood of relocating out of the area, and such a relationship is partially mediated by having friends nearby. This study is innovative because it identifies a stabilizing mechanism important for understanding protective factors, such as volunteering, as a way communities can retain older adults.     

整合外科与解剖教学,架构临床与基础桥梁

外科学与局部解剖学都是实践性很强的医学课程,但分属临床医学与基础医学,两者缺乏有效的衔接与充分的交流.为更好地培养医学人才,打破传统的课程框架,整合外科学与局部解剖教学,创立“模型及小动物外科技能训练—尸体解剖—手术观摩、视频教学及虚拟手术操作—大动物手术实验”四阶段实践教学,有效促进了外科学与局部解剖学的融合,有效提高了教师的教学水平,改善了学生知识理解与掌握的程度.     

浅析卫生政策类信息在传播中的误读——以“先诊疗后结算”为例

文章以媒体和受众对于卫生政策类信息“先诊疗后结算”的误读事件为例．并分析了其背后蕴含的原因,即网民不良情绪宣泄、政府与受众传播地位不对称和媒介“热岛效应”等,并结合实践探索性地提出了信息传播中政策类信息的传播方式。     

Engaged at work? An employee engagement model in public relations

ABSTRACT

Engagement has emerged as an important concept in public relations scholarship. Yet a theoretically informed model with a clear and coherent explication of the construct is still lacking. By situating our study in the internal organizational context, we provided an updated conceptualization and operationalization of employee engagement, proposing a strategy-engagement-behavior three-step employee engagement model. Results from an employee survey (n = 568) supported our conceptual model, showing that organizational engagement strategies positively predicted employee engagement, which in turn accounted for employees’ positive and negative messaging behavior, as well as their contextual performance behavior. After controlling for significant demographic variables such as gender, age, organizational size, number of subordinates, and level of management position, we identified a complete mediation effect of employee engagement in our two-step structural equation modeling analysis.