Testing diagonality of high-dimensional covariance matrix under non-normality

Under non-normality, this article is concerned with testing diagonality of high-dimensional covariance matrix, which is more practical than testing sphericity and identity in high-dimensional setting. The existing testing procedure for diagonality is not robust against either the data dimension or the data distribution, producing tests with distorted type I error rates much larger than nominal levels. This is mainly due to bias from estimating some functions of high-dimensional covariance matrix under non-normality. Compared to the sphericity and identity hypotheses, the asymptotic property of the diagonality hypothesis would be more involved and we should be more careful to deal with bias. We develop a correction that makes the existing test statistic robust against both the data dimension and the data distribution. We show that the proposed test statistic is asymptotically normal without the normality assumption and without specifying an explicit relationship between the dimension p and the sample size n. Simulations show that it has good size and power for a wide range of settings.     

A linear regression with unobserved dependent variables

Let (?,X) be a random vector such that E(X|?) = ? and Var(x|?) a + b? + c?² for some known constants a, b and c. Assume X₁,…,X_n are independent observations which have the same distribution as X. Let t(X) be the linear regression of ? on X. The linear empirical Bayes estimator is used to approximate the linear regression function. It is shown that under appropriate conditions, the linear empirical Bayes estimator approximates the linear regression well in the sense of mean squared error.     

Interactive association between negative emotion regulation and savoring is linked to anxiety symptoms among college students

Abstract

Objective: This study tested the interactive relationships between college students’ perceived capability of regulating negative emotions and savoring positive emotions on mental health outcomes, including anxiety and depressive symptoms. Participants: Participants were healthy undergraduates (n?=?167) recruited from two universities in Hong Kong. Methods: Students completed four scales assessing their perceived capability of using strategies to regulate negative and positive emotions and their anxiety and depressive symptoms. Results: Findings revealed that both anxiety and depressive symptoms were negatively linked to perceived capabilities of regulating negative emotions and savoring positive emotions. Furthermore, regulating negative emotions interacted with savoring positive emotions to predict anxiety symptoms. Conclusions: The need to simultaneously perform negative and positive emotion regulation is highlighted. The results suggest the priority of regulating negative emotions over savoring positive emotions in alleviating anxiety symptoms. Nevertheless, enhancing positive emotion shows greater benefits for those who are less adept at regulating negative emotions.     

带方郡的盛衰及其对海东地区的影响

公孙氏借东汉末年中原混乱之机割据辽东,公元3世纪初在乐浪郡南部设置了带方郡,曹魏时期带方郡已成为中原王朝在海东地区的实际代理人.随着西晋海东政策的转变,带方郡由盛转衰,后因其地缘政治价值与东亚海上交流的重要地位,成为周边部族争夺的焦点.带方郡在其存在的百余年间,对海东地区产生了重要影响.     

民宿的开发与设计探索——基于乡土聚落视角

乡村聚落承载着地理人文、农耕进化、乡愁乡思,给民宿的崛起和发展提供了优良的物质环境、文化民俗及情感基础。在乡村旅游产业发展中,如何进一步开发和设计具有加强主客交流、承载乡愁乡思、促进农村产业融合等优势的民宿,并在保护特色乡土聚落和地方建筑的同时,促进乡村旅游发展,实现振兴乡村、建设新型乡村文化的目标是本文需要研究的重点。     

县域农产品上行中的电商使能逻辑:基础场景与运行条件

在县域农产品上行实践中,市场主体进行与电商应用环境相适应的创业经营活动,将对技术和商业模式的被动适应转变为主动应用,不断实现动态能力的调整与更新,可视为电商使能过程.以重庆秀山为例的研究表明,县政府通过打造农产品上行体系,完善电商培训模式,为电商使能提供基础支撑.创业学习、多元合作以及市场规模增进,维持市场主体对技术和产业环境适应性,是电商使能的运行条件.作为市场创业内生性动力形成的结果,电商使能内嵌于市场主体的行为集合中,强调过程持续性、主体互动性与环境适应性.基于电商使能的逻辑框架,建议推动县域电商发展,要创新合作模式并加强市场主体连接,打造具备行业分工形态的产品上行服务体系,丰富营销手段合理引导本地消费,多部门合力共同开发和利用好数据资源等,从而助力特色农产品上行.     

杨凌示范区农民专业合作社发展探讨

近年来,杨凌示范区依靠区位优势、政策引导和技术支撑,培育组建农民专业合作社,发展特色产业,带动和促进了地方经济的发展,但同时也存在一些问题:如合作社规模小、重复性分散型经营;组织机构运行不规范;产、供、销体系不健全等,从而限制了合作社的进一步发展.为了促进杨凌示范区农民专业合作社向规范化、规模化、专业化、品牌化发展,应当从完善合作社章程,建立规章制度,规范运作;进行合作社之间有效合并或重组,扩大规模,创建品牌;争取政府在融资、税收方面的优惠政策;加强农民合作社人才培养等方面进一步改革.     

急诊医疗质量控制工作中的难点问题和对策

急诊医疗管理面临着缺乏统一的急诊建设标准模式、缺少稳定的高素质急诊专业人员、缺少足够的重视和投入、急诊流程不通畅等实际问题,导致了在急诊医疗质量控制工作中不易建立统一的急诊科建设管理质量标准、难以进行统一的急诊医生业务水平质量控制、急诊单病种质量控制操作困难、急诊质量控制工作纠偏困难等难点问题。只有制定统一的急诊科建设标准,规定急诊专业范畴,培养和建设一支强有力的急诊医疗队伍,保障质量控制考核结果有效执行,在卫生行政部门的监督下和医院领导的重视下才能顺利开展急诊质量控制工作,达到促进和提高急诊医疗质量的质控目的。     

红河哈尼梯田文化景观的形与神

在2013年6月世界遗产委员会第37届会议上申遗成功的“红河哈尼梯田文化景观”向世界展示了其“突出普遍价值”、独特性和唯一性。文化景观类型的世界遗产不仅包括外在的、有形的物质要素,而且蕴含内在的、无形的文化内涵,两者密不可分。物质要素是文化景观的“形”,文化内涵是文化景观的“神”,文化景观形神兼备、以形传神。文章从“森林-村寨-梯田-水系”四素同构的景观系统解析了红河哈尼梯田文化景观物质要素的“形”,以梯田稻作为核心的农耕文化为切入点分析了其文化内涵的“神”,并分析了两者之间的关系。在此基础上,剖析了红河哈尼梯田文化景观之所以列入世界遗产的最根本原因。通过解读红河哈尼梯田文化景观的本质,可以为其保护、可持续发展提供参考依据。