Rényi entropy of m-generalized order statistics

Abstract

Characterizing relations via Rényi entropy of m-generalized order statistics are considered along with examples and related stochastic orderings. Previous results for common order statistics are included.     

Mentorship experiences during registrar training: reflections of Black African specialists in the Western Cape

In order to meet the significant staffing challenges to health care provision in South Africa, the need to support the training and retention of Black medical specialists has been identified. This small qualitative study aimed to explore experiences of mentorship among a group of Black medical specialists in hopes of understanding the value and potential challenges that these relationships raise. Ten Black medical specialists were interviewed about their experiences of being mentored during their registrar training. The interview data was analysed using discourse analysis, and the results comprise of three main themes, namely: Difficulty accessing mentorship, a lack of Black and/or female role models and finally, experiences of feeling excluded from soft networks. The experiences explored in this study indicate the need for open dialogue within the mentorship dyad regarding certain taken-for-granted assumptions surrounding race, so as to aid the provision of more effective and satisfying mentorship outcomes.     

Inference and Decision Making for 21st-Century Drug Development and Approval

ABSTRACT

The cost and time of pharmaceutical drug development continue to grow at rates that many say are unsustainable. These trends have enormous impact on what treatments get to patients, when they get them and how they are used. The statistical framework for supporting decisions in regulated clinical development of new medicines has followed a traditional path of frequentist methodology. Trials using hypothesis tests of “no treatment effect” are done routinely, and the p-value < 0.05 is often the determinant of what constitutes a “successful” trial. Many drugs fail in clinical development, adding to the cost of new medicines, and some evidence points blame at the deficiencies of the frequentist paradigm. An unknown number effective medicines may have been abandoned because trials were declared “unsuccessful” due to a p-value exceeding 0.05. Recently, the Bayesian paradigm has shown utility in the clinical drug development process for its probability-based inference. We argue for a Bayesian approach that employs data from other trials as a “prior” for Phase 3 trials so that synthesized evidence across trials can be utilized to compute probability statements that are valuable for understanding the magnitude of treatment effect. Such a Bayesian paradigm provides a promising framework for improving statistical inference and regulatory decision making.     

重大公共卫生事件中应如何作为:来自医学人类学哈佛学派的启示

聚焦人类学者在针对重大公共卫生事件的跨学科研究中应该有何作为这一议题,通过借鉴来自医学人类学哈佛学派的民族志洞见和研究经验,为当下2019新型冠状病毒疫情危机中所进行的田野观察和分析,以期获得灵感和启示,并探索有可行性和操作性的研究策略和方法。     

Beyond tail median and conditional tail expectation: Extreme risk estimation using tail Lp-optimization

The conditional tail expectation (CTE) is an indicator of tail behavior that takes into account both the frequency and magnitude of a tail event. However, the asymptotic normality of its empirical estimator requires that the underlying distribution possess a finite variance; this can be a strong restriction in actuarial and financial applications. A valuable alternative is the median shortfall (MS), although it only gives information about the frequency of a tail event. We construct a class of tail L^p-medians encompassing the MS and CTE. For p in (1,2), a tail L^p-median depends on both the frequency and magnitude of tail events, and its empirical estimator is, within the range of the data, asymptotically normal under a condition weaker than a finite variance. We extrapolate this estimator and another technique to extreme levels using the heavy-tailed framework. The estimators are showcased on a simulation study and on real fire insurance data.     

用科学发展观指导医学教育改革和创新

科学发展观为高等医学教育的改革和发展提供了全新的思路。以科学发展观为指导,根据医学教育事业的发展,按照国际医学教育标准,全方位推进医学教育的改革和创新,强化素质教育,构建新的教学体系、管理监控体系以及教学保障体系,对于提高医学教学质量,培养高层次医学人才,实现国际标准本土化,具有重要的意义。     

Modelling daily multivariate pollutant data at multiple sites

Summary. This paper considers the spatiotemporal modelling of four pollutants measured daily at eight monitoring sites in London over a 4-year period. Such multiple-pollutant data sets measured over time at multiple sites within a region of interest are typical. Here, the modelling was carried out to provide the exposure for a study investigating the health effects of air pollution. Alternative objectives include the design problem of the positioning of a new monitoring site, or for regulatory purposes to determine whether environmental standards are being met. In general, analyses are hampered by missing data due, for example, to a particular pollutant not being measured at a site, a monitor being inactive by design (e.g. a 6-day monitoring schedule) or because of an unreliable or faulty monitor. Data of this type are modelled here within a dynamic linear modelling framework, in which the dependences across time, space and pollutants are exploited. Throughout the approach is Bayesian, with implementation via Markov chain Monte Carlo sampling.     

Computing maximum likelihood estimates from type II doubly censored exponential data

It is well-known that, under Type II double censoring, the maximum likelihood (ML) estimators of the location and scale parameters, θ and δ, of a twoparameter exponential distribution are linear functions of the order statistics. In contrast, when θ is known, theML estimator of δ does not admit a closed form expression. It is shown, however, that theML estimator of the scale parameter exists and is unique. Moreover, it has good large-sample properties. In addition, sharp lower and upper bounds for this estimator are provided, which can serve as starting points for iterative interpolation methods such as regula falsi. Explicit expressions for the expected Fisher information and Cramér-Rao lower bound are also derived. In the Bayesian context, assuming an inverted gamma prior on δ, the uniqueness, boundedness and asymptotics of the highest posterior density estimator of δ can be deduced in a similar way. Finally, an illustrative example is included.     

我校医学影像专业实施素质教育的实践与探索

三峡大学医学院开办医学影像专业有 16年历史 ,经历了从专科向本科转型过度。在素质教育和创新意识培养方面经过了多年的探索实践。大专层次的教育为社会培养了一批临床应用型专业人才 ,缓解了市场需求的压力 ,但部分学生客观上存在着知识面较窄小 ,缺乏后劲的问题。实施本科教育全面提高学生的综合素质需要在多方面下工夫 :转变教育思想 ,更新教育观念 ;转变培养模式 ;优化组合构建新的课程体系 ;强化科研 ,以科研促教学 ;通才教育与专才教育并举。探索本科生素质教育 6年 ,取得了可喜成绩 ,积累了一些经验     

非统计专业统计学教育刍议

针对非统计专业统计学教育目前存在的问题,阐述了提高对统计学重要性的认识是保证统计教学效果的前提;统计学教学环节的改革是提高教学效果的重要保证;统计教师的业务素质是提高统计教学效果的关键。