Semiparametric inference for a two-stage outcome-dependent sampling design with interval-censored failure time data

Lifetime Data Analysis - We propose a two-stage outcome-dependent sampling design and inference procedure for studies that concern interval-censored failure time outcomes. This design enhances the...     

Regression analysis of case-cohort studies in the presence of dependent interval censoring

The case-cohort design is widely used as a means of reducing the cost in large cohort studies, especially when the disease rate is low and covariate measurements may be expensive, and has been discussed by many authors. In this paper, we discuss regression analysis of case-cohort studies that produce interval-censored failure time with dependent censoring, a situation for which there does not seem to exist an established approach. For inference, a sieve inverse probability weighting estimation procedure is developed with the use of Bernstein polynomials to approximate the unknown baseline cumulative hazard functions. The proposed estimators are shown to be consistent and the asymptotic normality of the resulting regression parameter estimators is established. A simulation study is conducted to assess the finite sample properties of the proposed approach and indicates that it works well in practical situations. The proposed method is applied to an HIV/AIDS case-cohort study that motivated this investigation.     

综合医院里的临终关怀——妇科肿瘤病房和ICU的人类学观察

临终关怀需要多学科合作研究,医学界、社会科学界关注较多的是独立的临终关怀医院或病区,对仍以治疗为主的综合医院,尤其是肿瘤病房和重症监护病房病人的临终关怀缺乏应有的关注。笔者通过对北京某三甲综合医院妇科肿瘤病房和ICU的观察,以及对中国临终关怀发展历程的文献梳理,得出以下结论:(1)中国的临终关怀肇始于西方医学,医学界、社会科学界不断地反思、找寻适合本土化的临终关怀实践;(2)临终关怀事业的发展需要政府政策、制度的支持。(3)在非普遍人性的原则下,不同区域人民不同的风俗、信仰应该得到医院所处地区的关注。     

The Impact of Limited Supply on a Firm's Bundling Strategy

A firm's two‐product bundling decision is examined when the supply of one product is limited and consumer valuations are normally distSteckeributed. The firm can choose to sell products separately and/or through a bundle. We find that the impact of limited supply on a firm's bundling decision depends on the correlation between the consumer valuations of the two products as well as the symmetry level of the two products in terms of their attractiveness (how much they are valued by consumers). When the valuation correlation is high and the symmetry level of the two products is low, limited supply can drive bundling. When the valuation correlation is low or the symmetry level is high, limited supply can drive no bundling. When the attractiveness of both products are low or the valuation correlation is very high, limited supply has no impact on a firm's bundling decision: The firm should not bundle for all supply levels. This study offers a new driver for product bundling: the limited supply of a product. The existing bundling literature suggests that a firm should bundle symmetric products that have a low consumer valuation correlation, when bundling is driven by consumer valuation heterogeneity reduction. In contrast, when bundling is driven by limited supply, a firm should bundle asymmetric products with a high consumer valuation correlation. The benefit of supply‐driven bundling depends on the severity of supply limitation. When supply limitation is moderate, bundling creates value by expanding the market of the less attractive product. When supply limitation is severe, bundling enables a firm to extract a higher margin from the less attractive product.     

民俗体育的当代价值

21世纪休闲娱乐体育活动将在人们生活中扮演着越来越重要的角色。从我国农村开展休闲娱乐体育的社会条件来看,民俗体育无疑是其活动的主要形式。促进农村休闲娱乐体育的可持续发展正是民俗体育的当代价值。