A log rank type test in observational survival studies with stratified sampling

In randomized clinical trials, the log rank test is often used to test the null hypothesis of the equality of treatment-specific survival distributions. In observational studies, however, the ordinary log rank test is no longer guaranteed to be valid. In such studies we must be cautious about potential confounders; that is, the covariates that affect both the treatment assignment and the survival distribution. In this paper, two cases were considered: the first is when it is believed that all the potential confounders are captured in the primary database, and the second case where a substudy is conducted to capture additional confounding covariates. We generalize the augmented inverse probability weighted complete case estimators for treatment-specific survival distribution proposed in Bai et al. (Biometrics 69:830–839, 2013) and develop the log rank type test in both cases. The consistency and double robustness of the proposed test statistics are shown in simulation studies. These statistics are then applied to the data from the observational study that motivated this research.     

天津城市游憩商业区(RBD)初步研究

一、问题的提出 随着经济的发展和信息时代的来临,城市越来越以多样化的功能显示出其区域核心的地位,城市不仅担当起区域经济、文化、政治、信息服务的中心,更成为旅游活动的中心,而且旅游中心的功能作为城市共性的功能会随着城市的发展得到不断强化.     

Ethnic Identities under the Tourist Gaze

This paper examines the construction of Bai ethnicity and Bai identity on the tourist market in Dali, Dali Bai Autonomous Prefecture, Yunnan, China. Focusing on how the social landscape of Dali has changed in response to the development of tourism, this paper explores how Bai ethnicity is advocated as a product loaded with potential economic values. The author discovers that ‘commerce of authenticity’ (T. Oakes, Tourism and modernity in China. London, Routledge, 1998 Oakes, T. 1998. Tourism and modernity in China, London: Routledge.  [Google Scholar]), and different forms of ethnicity and artefacts promoted in the tourist market have not drowned out the sense of being ethnically Bai. Instead, the tourist industry has become a daily reminder of ethnicity to both insiders and outsiders by making people more self-conscious and reflexive about the ‘cultural stuff’ that they may have previously taken for granted, or may have left unattended. This paper demonstrates how locals actively appropriate state-defined categories and reshape them into the repertoire they desire.     

民俗文化与甘肃旅游业的发展

甘肃旅游业的一大优势在于丰富的少数民族民俗文化旅游资源。大力发展甘肃少数民族的民俗文化资源,形成以各民族典型节日庆典为主要内容、以民俗美为核心的民俗旅游体系,充分发挥少数民族旅游胜地立体化旅游资源优势,对推动甘肃的经济具有很强的实践性和深远的意义。     

Hard thresholding regression

In this paper, we propose the hard thresholding regression (HTR) for estimating high‐dimensional sparse linear regression models. HTR uses a two‐stage convex algorithm to approximate the ?₀‐penalized regression: The first stage calculates a coarse initial estimator, and the second stage identifies the oracle estimator by borrowing information from the first one. Theoretically, the HTR estimator achieves the strong oracle property over a wide range of regularization parameters. Numerical examples and a real data example lend further support to our proposed methodology.     

基于雨课堂的电工电子学混合式智慧教学方法研究

《电工电子学》是高等学校针对非电类工科专业开设的一门有关电工、电子技术的重要专业基础课。针对《电工电子学》传统理论教学空洞乏味、师生互动不足、学生学习兴趣不足等问题,在《电工电子学》课程教学中引入雨课堂智慧教学工具,论述了雨课堂从课前、课上和课后三个方面实践的特点和使用方法,实践表明,基于PPT和微信的雨课堂混合传统教学的教学方法可以实现师生实时线上互动,建立多元化科学评价机制,激发学生学习主动性,活跃课堂气氛,提高学生学习积极性,改善本门课程的教学效果。     

马克思生态哲学思想的当代价值

马克思生态哲学从人的实践活动出发研究人与自然的辩证关系和人与社会的辩证关系,认为自然的异化归根结底是人与人关系恶化的结果,解决自然的异化必须通过社会变革才能实现。只有在共产主义社会,这个问题才能真正解决。这些生态哲学思想为人类解决全球生态危机问题指明了方向,为可持续发展战略提供了理论基础,对我国构建社会主义和谐社会具有重要的指导价值。     

连铸结晶器保护渣生产及应用技术的发展

介绍连铸结晶器保护渣生产及应用技术的发展现状,提出了发展我国结晶器保护渣生产及应用技术的几点建议.     

信息不对称条件下的产品质量的信号功能分析

本文首先给出了不确定条件下产品质量的效用函数,然后分析了四种信息不对称条件下厂商的质量决策问题,并对实施名牌战略企业的质量决策问题进行了分析。我们的研究表明,消费者对产品质量信息获取程度与政府监管水平都会影响厂商的质量决策。消费者对产品质量信息获取程度越高,厂商越会努力提高产品质量水平;另一方面,对于产品质量的有力监管也会促使厂商提高产品质量水平。     

以社会主义核心价值体系引领高校校园文化建设

高等学校肩负着培养中国特色社会主义事业的建设者和接班人的历史使命,是践行社会主义核心价值体系的关键场所。以社会主义核心价值体系引领校园文化建设,就是要以马克思主义指导思想作为校园文化建设的理论基础,以实现中国特色社会主义作为校园文化建设的共同理想,以培育和弘扬以爱国主义为核心的民族精神和以改革创新为核心的时代精神作为校园文化建设的根本任务,以树立和践行社会主义荣辱观作为校园文化建设的主要内容。