浅论中等职业技术学校化学课堂教学

中等职业技术学校的化学课堂教学有其独特性,并存在着一些问题。在当前的化学课堂教学中,可以从培养学生创新实践能力和探究能力,绘制理想教学模型,加强课堂应变技巧及突出个性发展教学、激发学生学习兴趣等内容和环节上逐步加强教学能力。     

Model‐based clustering of longitudinal data

A new family of mixture models for the model‐based clustering of longitudinal data is introduced. The covariance structures of eight members of this new family of models are given and the associated maximum likelihood estimates for the parameters are derived via expectation–maximization (EM) algorithms. The Bayesian information criterion is used for model selection and a convergence criterion based on the Aitken acceleration is used to determine the convergence of these EM algorithms. This new family of models is applied to yeast sporulation time course data, where the models give good clustering performance. Further constraints are then imposed on the decomposition to allow a deeper investigation of the correlation structure of the yeast data. These constraints greatly extend this new family of models, with the addition of many parsimonious models. The Canadian Journal of Statistics 38:153–168; 2010 © 2010 Statistical Society of Canada     

Use of non-normality in structural equation modeling: Application to direction of causation

Structural equation modeling (SEM) typically utilizes first- and second-order moment structures. This limits its applicability since many unidentified models and many equivalent models that researchers would like to distinguish are created. In this paper, we relax this restriction and assume non-normal distributions on exogenous variables. We shall provide a solution to the problems of underidentifiability and equivalence of SEM models by making use of non-normality (higher-order moment structures). The non-normal SEM is applied to finding the possible direction of a path in simple regression models. The method of (generalized) least squares is employed to estimate model parameters. A test statistic for examining a fit of a model is proposed. A simulation result and a real data example are reported to study how the non-normal SEM approach works empirically.     

Model for an Employee Wellness Project

Abstract

A pilot project designed to assess the feasibility and effectiveness of a health-related employee assistance program was implemented at the University of South Carolina. One hundred interested participants were randomly selected from university faculty and administrative staff. The project utilized the following methods: 1) psychophysical tests including health risk appraisals, health knowledge levels, physical activity assessments, psychological batteries of tests, and biophysical data obtained through a treadmill stress test, percent body fat, blood analysis, blood pressure, and pulmonary function; 2) individual health consultants who served to inform, model, and encourage participants to practice healthful behaviors; 3) group programs related to self-care/wellness promotion techniques; 4) mass media contact to repeat and reinforce healthful behaviors; 5) wellness-oriented social activities, such as fun runs, meatless covered dish dinners, etc.

Results of the project included statistically significant pre/post change in weight, percent body fat, physical activity scores, health knowledge levels, pulmonary function, and self-esteem.

The positive, enthusiastic group attitude and sustained project involvement all suggest the effectiveness of the model as an employee health intervention program.     

Cox regression for current status data with mismeasured covariates

Covariate measurement error problems have been extensively studied in the context of right‐censored data but less so for current status data. Motivated by the zebrafish basal cell carcinoma (BCC) study, where the occurrence time of BCC was only known to lie before or after a sacrifice time and where the covariate (Sonic hedgehog expression) was measured with error, the authors describe a semiparametric maximum likelihood method for analyzing current status data with mismeasured covariates under the proportional hazards model. They show that the estimator of the regression coefficient is asymptotically normal and efficient and that the profile likelihood ratio test is asymptotically Chi‐squared. They also provide an easily implemented algorithm for computing the estimators. They evaluate their method through simulation studies, and illustrate it with a real data example. The Canadian Journal of Statistics 39: 73–88; 2011 © 2011 Statistical Society of Canada     

风险投资退出途径:比较、问题与解决方法

文章比较和分析了风险投资三种退出途径的优缺点和适用条件,提出我国借鉴国际经验,创造条件,尽快改善退出机制,支持风险投资的发展思路与建议。      

老年冠心病患者红细胞免疫功能与BNP、CD62P的临床意义

目的探讨老年冠心病（CHD）患者外周血红细胞免疫功能（EIF）与脑钠肽（BNP））、P-选择素（CD62P）的变化及其临床意义。方法采用“郭峰改良法”、干式快速荧光免疫法及流式细胞技术检测88例老年CHD患者外周血红细胞C3b受体花环率（RBC—C3bRR）、红细胞免疫复合花环率（RBC—ICR）、BNP和CD62P,并与32例健康老年人比较。结果CHD组的RBC—C3bRR与对照组无明显差异,RBC—ICR、BNP及CD62P则CHD组明显高于对照组,尤以急性心肌梗死组（AMI）和不稳定型心绞痛组（UAP）为甚（P〈0．01）。结论老年CHD存在严重的EIF低下,免疫机制和炎症因子BNP、CD62P可能是急性冠脉综合症（ACS）发病中的一个重要因素,并可能与斑块的不稳定性有关。     

基于二次孵化的高技术产业政策

高技术产业政策的制定与实施对发展一国经济有着深远影响。二次孵化的提出将科技孵化从企业孵化提升到产业孵化。在借鉴其他国家或地区发展高技术产业经验的基础上,结合二次孵化的概念,提出高技术产业的发展政策,包括健全产权机制、促进资金融通、优化土地资源配置、加强孵化器人才培养、促进技术转移等。     

三种誓言及其超越：作为第一方监督的人力资源管理中的非正式制度问题研究

在当前的人力资源管理的实践运作和管理探讨中,很多的做法和研究都集中在了第二方监督和第三方监督上,而对第一方监督的考量却显得较少或者说关注不够。这里从三种誓言及其可能的超越层面入手,给出了基于第一方监督条件下的人力资源管理中的非正式制度问题研究。具体说来,直面新时期人力资源管理实践与挑战,探讨了在组织运营中,除了一些正式的硬性制度条文之外,一些个可操作性的非正式的柔性约束以及协力提升问题,并给出了其未来尽可能调整优化的对策和建议方面的一些引领性思考。     

ARMA MODELS REALIZATION AND IMPULSE RESPONSES

A parallel is made between the role played by covariances in the determination of auto-regressive models and the role played by impulse responses in the determination of ARMA models.

Auto-regressive models are known to maximize the Burg-entropy under covariance constraints. Auto-regressive-moving-average models give the maximum of the Burg-entropy among processes sharing the same covariances and impulse responses up to a certain lag. Such models are constructed by iterative or algebraic methods under the different constraints.

A new recursive method of identification of the order of an ARMA model is also developed, based on the generalized reflection coefficients.