食品安检专业开设动物病理学课程的改革与探索

本文从专业现状及教学中存在的问题,对食品安检专业开设动物病理学课程的教学改革相关问题进行阐述,为全面培养高素质的食品安检专业人才提供经验。     

应用现代教育技术提高教育教学质量

现代教育技术朝着智能化、多媒化、网络化的方向发展,具有教学信息资源和信息渠道多元化、课堂教学开放化、教学手段智能化以及教学过程情景化等特点。而课堂教学现代化是提高教学质量的有效途径,通过合理应用现代教育技术手段,使教学效果达到最优化。     

我国森林资源境外开发对策研究

森林资源境外开发是森林资源三大供给体系的重要组成部分,是指运用相关理论,采取一定的方式与手段与本国以外的国家、地区、企业发生的一些具体的林业经济关系。文章分析了我国林业利用国外森林资源战略目标及实现条件,研究并提出一系列措施。     

虚拟社区中的人际互动

网络的特殊性改变了传统的人际互动模式,形成了一个新的人际交往空间———虚拟社区。人们在其中依靠化名的身份建立起类似于现实社会中的人际互动。虚拟社区能够满足人们在现实生活中所不能完全得到满足的心理需求。     

建筑工程项目管理分析

阐述了建筑工程项目管理的主要内容,指出建筑工程项目管理是建筑企业根据经营发展战略和企业内外条件,按照现代企业运行规律,通过生产诸要素的优化配置和动态管理,以实现工程项目的合同目标、工程经济效益和社会效益.文章重点分析了在建筑工程项目管理中目标管理、技术协调和成本控制等问题,从影响建筑工程项目因素的角度,探讨了应把成本、质量、服务作为整体系统管理的基本思路.     

市场营销学研究性学习的理论与实践

“市场营销学”是一门理论与实践紧密结合的课程。引入研究性学习,以课业作为研究性学习的教学环节,以课题研究作为研究学习的驱动力,以学习小组作为研究性学习的组织形式,以网络研究性学习的平台,有利于实现市场营销教学目的,促进营销教师成长,调动学生的学习积极性。     

Classification with minimum ambiguity under distribution heterogeneity

The traditional classification is based on the assumption that distribution of indicator variable X in one class is homogeneous. However, when data in one class comes from heterogeneous distribution, the likelihood ratio of two classes is not unique. In this paper, we construct the classification via an ambiguity criterion for the case of distribution heterogeneity of X in a single class. The separated historical data in each situation are used to estimate the thresholds respectively. The final boundary is chosen as the maximum and minimum thresholds from all situations. Our approach obtains the minimum ambiguity with a high classification accuracy allowing for a precise decision. In addition, nonparametric estimation of the classification region and theoretical properties are derived. Simulation study and real data analysis are reported to demonstrate the effectiveness of our method.     

Graphical representation of survival curves in the presence of time-dependent categorical covariates with application to liver transplantation

Graphical representation of survival curves is often used to illustrate associations between exposures and time-to-event outcomes. However, when exposures are time-dependent, calculation of survival probabilities is not straightforward. Our aim was to develop a method to estimate time-dependent survival probabilities and represent them graphically. Cox models with time-dependent indicators to represent state changes were fitted, and survival probabilities were plotted using pre-specified times of state changes. Time-varying hazard ratios for the state change were also explored. The method was applied to data from the Adult-to-Adult Living Donor Liver Transplantation Cohort Study (A2ALL). Survival curves showing a ‘split’ at a pre-specified time t allow for the qualitative comparison of survival probabilities between patients with similar baseline covariates who do and do not experience a state change at time t. Time since state change interactions can be visually represented to reflect changing hazard ratios over time. A2ALL study results showed differences in survival probabilities among those who did not receive a transplant, received a living donor transplant, and received a deceased donor transplant. These graphical representations of survival curves with time-dependent indicators improve upon previous methods and allow for clinically meaningful interpretation.     

Cox regression of clustered event times with covariates missing not at random

Motivated by a recent tuberculosis (TB) study, this paper is concerned with covariates missing not at random (MNAR) and models the potential intracluster correlation by a frailty. We consider the regression analysis of right‐censored event times from clustered subjects under a Cox proportional hazards frailty model and present the semiparametric maximum likelihood estimator (SPMLE) of the model parameters. An easy‐to‐implement pseudo‐SPMLE is then proposed to accommodate more realistic situations using readily available supplementary information on the missing covariates. Algorithms are provided to compute the estimators and their consistent variance estimators. We demonstrate that both the SPMLE and the pseudo‐SPMLE are consistent and asymptotically normal by the arguments based on the theory of modern empirical processes. The proposed approach is examined numerically via simulation and illustrated with an analysis of the motivating TB study data.     

Semiparametric Bayesian analysis for longitudinal mixed effects models with non-normal AR(1) errors

Statistics and Computing - This paper studies Bayesian inference on longitudinal mixed effects models with non-normal AR(1) errors. We model the nonparametric zero-mean noise in the autoregression...