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.     

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.     

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.     

不精确Newton法与Broyden法的仿射不变收敛性

给出了不精确Ｎｅｗｔｏｎ法的半局部收敛性定理，通过改善条件γ＿ｋ／Ｆ（ｘ￣ｋ）≤η＿ｋ（ｋ＝０，１…）使其具仿射不变性，建立起了不精确Ｎｅｗｔｏｎ法的具仿射不变性的半局部收敛定理，在一定条件下，讨论了Ｂｒｏｙｄｅｎ方法的具仿射不变性的存在──收敛定理，从而，扩大了这两种方法收敛定理的收敛域。     

藏彝走廊中"藏回"的民族认同及其主体性——以云南省迪庆藏族自治州香格里拉县"藏回"为例

本文以生活在云南省迪庆藏族自治州的"藏回"为研究对象,运用人类学理论和方法,将民族认同放在具体的历史、政治和社会情景中来讨论,分析"藏回"身份认同的特点,挖掘、再现研究对象的主体性(subjectivity),挑战回族族源多元但认同一元的观点.本文将说明迪庆藏族与回族之间的族群界限是模糊的、流变的,他们表现出来的主体性和历史记忆是建构"藏回"身份认同的主要因素,文化实践只是"藏回"认同的一个表层依据.     

少数民族民间纠纷解决机制的现实困境及其破解

少数民族民间纠纷解决机制的诸多缺陷是少数民族民间纠纷解决纠纷机制正常运行的主要障碍,现实困境主要表现于诉讼解决纠纷机制的弊端、非诉讼解决机制的制度设计缺陷以及二者衔接的不合理.     

Parameter estimation of the censored δ-shock model on uniform interval

The censored δ-shock model is a special kind of shock model and it has very important research values in the reliability theory. In this paper, we discuss the parameter estimation of the censored δ-shock model when the inter-arrival times between two successive shocks follows uniform distribution on [a, b]. With the maximum likelihood estimation, we obtain the parameter estimator and expectation of estimator and lifetime of the model. By numerical simulation, we get the empirical result on the estimator of δ and the relationship between δ and other parameters.     

政府采购招标结构模型的非参数识别与估计

为了揭示政府采购市场的定价机制,探究招标活动的经济机理,本文首先提出了一种基于可观测成交价(即赢价)建立招标结构模型的方法,分析了博弈均衡的分布;然后讨论了该模型的非参数识别,提出了一种三阶段非参数核估计方法.最后,以中央单位集中采购打印机为例,估计了政府采购招标的成本分布和期望供给曲线.研究发现,当前的政府采购机制改革有效地降低了采购成本;对于附加成本较高的商品,投标人存在成本转移行为.     

世界科技创新趋势与启示

现阶段"现代化进程强大的客观需求"和"知识技术体系的内在矛盾"正孕育着新一轮科技革命,世界正处在第六次科技革命的前夜。200多年的工业化进程催生出一系列问题。经济发展的客观需求迫切需要开发新的资源能源,创新发展模式和发展途径,创建新的生产方式和生活方式。"基础科学领域""能源和资源域""信息网络领域""先进材料和制造领域""农业领域""人口健康领域"这六个方面孕育着重大的创新突破。科学问题的重大突破和技术的变革将深刻影响人类的生产和生活方式,影响社会发展的进程,影响国家的国际竞争地位。把握新一轮科技革命的战略机遇,将大幅提升我国自主创新与规模产业化的能力。     

对晋商劳动力激励制度的两点思考

明清晋商为调动其劳动力的积极性采取了一套特别的激励制度,时称顶身股制。深入分析该制度对我国目前企业管理制度的改进具有一定启发意义。在晋商顶身股制度下,让员工参与企业未来权益分配的思路可以给我们以参考,但必须视企业发展阶段选择适当的薪酬性激励手段。总之,认清形势,适时而动才是现代企业应付激烈市场竞争的不败法则。