Nested exposure case-control sampling: a sampling scheme to analyze rare time-dependent exposures

For large cohort studies with rare outcomes, the nested case-control design only requires data collection of small subsets of the individuals at risk. These are typically randomly sampled at the observed event times and a weighted, stratified analysis takes over the role of the full cohort analysis. Motivated by observational studies on the impact of hospital-acquired infection on hospital stay outcome, we are interested in situations, where not necessarily the outcome is rare, but time-dependent exposure such as the occurrence of an adverse event or disease progression is. Using the counting process formulation of general nested case-control designs, we propose three sampling schemes where not all commonly observed outcomes need to be included in the analysis. Rather, inclusion probabilities may be time-dependent and may even depend on the past sampling and exposure history. A bootstrap analysis of a full cohort data set from hospital epidemiology allows us to investigate the practical utility of the proposed sampling schemes in comparison to a full cohort analysis and a too simple application of the nested case-control design, if the outcome is not rare.

     

Writing Distinction – Eine illegitime Kultur als subkulturelles Feld

Graffiti is an illegitimate culture, yet with high potential for distinction and abstract aesthetic principles. The article considers these characteristics as result of the process of the autonomization of graffiti as subcultural field and aims to reconstruct its field logic.     

Gender differences in predictors of late-life health insurance knowledge

For many older adults having access to affordable health care is a major concern. The present study's goal was to examine what factors were related to individuals' knowledge of late-life health insurance. A total of 131 women and 116 men (all aged 55-71) answered questions about private, Medicare, Medigap, and long-term care insurances. In addition, they answered demographic, personality, and health status questions. Results revealed that different factors are related to men's and women's knowledge of late-life health insurance options implying genderspecific educational interventions would be more effective than current educational interventions.     

The time‐dependent “cure‐death” model investigating two equally important endpoints simultaneously in trials treating high‐risk patients with resistant pathogens

A variety of primary endpoints are used in clinical trials treating patients with severe infectious diseases, and existing guidelines do not provide a consistent recommendation. We propose to study simultaneously two primary endpoints, cure and death, in a comprehensive multistate cure‐death model as starting point for a treatment comparison. This technique enables us to study the temporal dynamic of the patient‐relevant probability to be cured and alive. We describe and compare traditional and innovative methods suitable for a treatment comparison based on this model. Traditional analyses using risk differences focus on one prespecified timepoint only. A restricted logrank‐based test of treatment effect is sensitive to ordered categories of responses and integrates information on duration of response. The pseudo‐value regression provides a direct regression model for examination of treatment effect via difference in transition probabilities. Applied to a topical real data example and simulation scenarios, we demonstrate advantages and limitations and provide an insight into how these methods can handle different kinds of treatment imbalances. The cure‐death model provides a suitable framework to gain a better understanding of how a new treatment influences the time‐dynamic cure and death process. This might help the future planning of randomised clinical trials, sample size calculations, and data analyses.     

On pseudo-values for regression analysis in competing risks models

For regression on state and transition probabilities in multi-state models Andersen et al. (Biometrika 90:15–27, 2003) propose a technique based on jackknife pseudo-values. In this article we analyze the pseudo-values suggested for competing risks models and prove some conjectures regarding their asymptotics (Klein and Andersen, Biometrics 61:223–229, 2005). The key is a second order von Mises expansion of the Aalen-Johansen estimator which yields an appropriate representation of the pseudo-values. The method is illustrated with data from a clinical study on total joint replacement. In the application we consider for comparison the estimates obtained with the Fine and Gray approach (J Am Stat Assoc 94:496–509, 1999) and also time-dependent solutions of pseudo-value regression equations.     

Energy modelling: A new challenge for management science

The Arab oil embargo in 1973 and the subsequent price rises and production restrictions have given birth to a distinct branch within Management Science: energy modelling. This paper gives a critical and selective review on energy modelling, an industry which though thriving in an era of general economic anxiety, is showing signs of arrogant immaturity. After giving a historical background, the paper classifies energy models into three groups: open loop demand or supply models; energy closed loop models; energy-economy closed loop models. For each group the problem area is analysed and some illustrative examples are described. In the last sections, an attempt is made to sum up the experience that has been gained with energy modelling: the basic deficiencies, the impact of this activity on policy formulation and its position within Management Science. It is concluded that energy models, though very poor forecasting devices, can be very useful to policy makers as tools for analysis; energy model developers must convince potential model users and for that purpose they can benefit immensely from the 35-year-long experience accumulated by their colleagues in Management Science.     

Large scale communication networks—Design and analysis

The paper discusses the problem of design and analysis of large scale communication systems. An iterative process, composed of a minimum cost network design algorithm and a network performance algorithm, is presented for the solution of these problems. Computational considerations, using these algorithms, are discussed.     

The use of strategic planning techniques in the United Kingdom

In this paper some of the techniques available for strategic planning are reviewed. Four techniques are presented, the experience curve, the growth-share matrix, the directional policy matrix and the PIMS program. The results of a survey into the use of these techniques in the United Kingdom are also presented.     

近四十年来韩国《史记》研究综述（1971—2010）

《史记》是中国史学中一部继往开来的不朽巨著,作者司马迁开创的以人物为中心的纪传体,在汉代以后一直是历代王朝正史所沿用的体制。司马迁修《史记》,不仅尊重历史事实,秉笔直书,而且还注意语言文字的锤炼,文句优美。他将叙事、抒情、说理的不同文体有机地综合起来,达到思想上、艺术上的高度统一,为后代文史创作提供了范例。《史记》不仅是中国纪传体史书的开创者,而且对后世的散文、小说、戏曲都产生了深远的影响。同时它也早已流传至国外,在汉文化圈国家中亦有不小的影响。其中,《史记》传入韩国,特别受到韩国知识界人士的关心和推崇,为韩国学术界所重视。到了1960年代中期,随着国家经济的发展,韩国整个社会的发展进入了一个历史的新时期,不仅国家面貌发生了根本性变化,学术文化事业也步入正轨,同时韩国学术界对中国学术文化的关心及研究也重新得到了高度重视。正是在这样的基础上,韩国学者对《史记》的翻译和研究有了较大的进展,在传播、普及和通俗化方面作出了积极的贡献。本文除简述《史记》在韩国的流传背景外,还分别论述自1971年至2010年近四十年来《史记》在当代韩国的翻译介绍与研究现状,并对其研究成果上存在的一些不足和空缺作一番客观的评价。