Accurate computation of single and product moments of order statistics under progressive censoring

An accurate procedure is proposed to calculate approximate moments of progressive order statistics in the context of statistical inference for lifetime models. The study analyses the performance of power series expansion to approximate the moments for location and scale distributions with high precision and smaller deviations with respect to the exact values. A comparative analysis between exact and approximate methods is shown using some tables and figures. The different approximations are applied in two situations. First, we consider the problem of computing the large sample variance–covariance matrix of maximum likelihood estimators. We also use the approximations to obtain progressively censored sampling plans for log-normal distributed data. These problems illustrate that the presented procedure is highly useful to compute the moments with precision for numerous censoring patterns and, in many cases, is the only valid method because the exact calculation may not be applicable.     

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.     

美国中小学的体验式学习及启示

体验式学习的内涵随着时代的发展而逐渐丰富和深化，但无论其如何演变，直接经验和反思始终是体验式学习这一概念的内核。体验式学习理念渗透于美国教育文化之中。具体表现在：小学阶段的教育以学生的真实感知为基础，注重为学生提供真实体验的机会和激发学生的学习兴趣；中学尤其是高中阶段的教育以学生的真实体验为基础，注重为学生提供在新情境中检验所学知识的机会，注重学生知识、技能的内化吸收。美国中小学体验式学习的实施经验可为我国基础教育课程改革提供如下启示：（1）进一步树立和推广体验式学习理念；（2）创设学生进行真实体验的教学环境；（3）注重实施基于学生体验式学习的表现性评价。     

Identifying the priorities for midwifery education across Australia and New Zealand: A Delphi study

ProblemIn countries where education programmes are assessed as meeting international standards there is limited knowledge about the challenges facing midwifery education.Background/aimThe positive impact of quality midwifery education on maternal and newborn health is acknowledged by the World Health Organisation. However, there is limited research identifying the issues faced in providing quality midwifery education. The aim of this study was to identify the challenges and determine priority projects to strengthen midwifery education across Australia and New Zealand.MethodsA two-round Delphi study with experts in midwifery education was undertaken.FindingsIn round one, 85 participants identified an initial 366 issues for midwifery education. Through thematic content analysis these were categorised into 89 statements reflecting five major themes: In round two, 105 midwifery experts from Australia n = 86 (79%) and New Zealand n = 23 (21%) rated the 89 statements in order of priority. Across the combined data (Australia and New Zealand) a total of 19 statements gained consensus of ≥80%.DiscussionFive priority themes were identified including; (1) enabling success of First Peoples/Māori midwifery students; (2) increasing the visibility and influence of midwifery within regulation, accreditation and university governance; (3) determining how best to deliver the clinical practicum component of programmes; (4) reviewing midwifery programmes to enhance design, content and delivery; and (5) ongoing education and support for the midwifery workforce.ConclusionIn Australia and New Zealand, it is imperative that collaborative work is undertaken to design and action identified projects addressing these priorities.     

On MLEs of the parameters of a modified Weibull distribution based on record values

The modified Weibull distribution can be used quite effectively to model complex data from mechanical engineering or survival analysis studies that posses a monotonic or a bathtub-shape hazard rate. In this paper, we study the MLEs of the parameters of a modified Weibull distribution model in the presence of upper kth record values. The existence and uniqueness of the MLEs are proven in this case. Real data analysis is performed for illustrative purposes.     

Women migrants in the global economy: a global overview (and regional perspectives)

ABSTRACT

Huge advances have been made in deepening and expanding our knowledge of gendered migration over the last decades in both theoretical and methodological terms. Empirically it is, however, still the case that North–South migration is at the basis of most theorisations, leaving the characteristics of South–South migration at the margins. In this paper we, therefore, shift the focus to intra- and trans-regional migration in a South–South context in exploring what this means for women migrants. While feminist scholars have highlighted care and the ways in which migration challenges social reproduction as an important issue, mainstream approaches continue to focus predominantly on the ‘productive’ lives of migrant workers. With migration theories still largely drawing on the experience of South–North migration, there continues to be relatively little understanding of South–South migration’s gender dynamics, despite the fact that many of the highly feminised, yet hyper-precarious, migration flows occur intra-regionally.     

我国中小学校园欺凌问题研究及薄弱环节——基于CNKI文献关键词的共词分析

随着一系列恶性事件被媒体曝光，社会各界普遍关注和担忧校园欺凌问题，如何解决这一问题，已成为社会焦点。通过共词分析法对我国中小学校园欺凌问题研究现状进行考察发现，其研究主题主要包括六大类：校园欺凌行为特征研究、校园欺凌与学校管理的关系研究、校园欺凌与人际交往的关系研究、校园欺凌的成因与对策研究、校园欺凌的预防与治理研究、校园欺凌的社会问题研究，而研究的薄弱环节则主要包括品格教育研究、学生自我保护研究以及网络欺凌问题研究。因此，校园欺凌问题研究亟待进一步深化，研究视角也需进一步拓展。首先，除欺凌者、被欺凌者之外，旁观者也应纳入研究范畴，要将欺凌者和被欺凌者实施隔离，对受欺凌者要及时给予心理疏导，引导旁观者积极主动地帮助被欺凌者；其次，建议尽快出台相关的法律法规，为学校、教师及相关部门有效处理、解决校园欺凌问题提供法律支持及保障；最后，将综合预防与治理相结合，建立由学校、教师、学生组成的反欺凌共同体。     

近代巴蜀诗人李士棻生卒年及别号考略

近代巴蜀诗人李士棻曾被曾国藩誉为“太白醉魂”，为曾府门下“四川三李”之一，其诗作有浓郁的巴蜀文化特色。然李氏仕宦不显，长期以来学界对其关注不足，学界近年不多的相关研究，多围绕国内所存的文献，对其诗歌创作进行艺术分析，对诗人的生平介绍多简单略过，没有严谨的考证，目前仍然很有争议。通过搜罗国内外现存典籍，综合目前所见李士棻本人著述，辅以晚清近代重要报刊《申报》和与李氏有交往的朝鲜文人文献，考证其生卒年及别号，冀为今后的相关研究解决基础问题。