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.

     

Statistical Analyses and Modelling of the Mixing Process of Euro Coins in Germany and Europe

This paper reports on the mixing of Euro coins from different countries of origin in Europe, which started on 1 January 2002. There is an interesting conclusion: that the mobility of small and large denominations is different. The long‐term behaviour of the mixing process is studied using a simple deterministic model and data from Germany, France and the Netherlands. The analysis leads to predictions about the future progress of the mixing process.     

Population growth,farmland, and the long-run standard of living

This paper studies the natural-resources element in the theory of population growth over the very long run. In the context of the stock of land and Malthusian crises in earlier times, the model shows how resources have become more available rather than more scarce, even as population and income have increased.The paper sketches a mechanism which, added to the Malthusian system, leads to entirely different conclusions than does the Malthusian system. Using the illustration of food and land, change in knowledge and hence in the stock of resources is made a function of the stock of knowledge and the price of resources. The speed of adjustment depends on the economic and social climate for the development of new knowledge. Population growth first raises food and land prices, which then stimulate the creation of new resources, eventually leading to less scarcity of resources and lower prices than originally prevailed.That is, population growth creates new problems which in the short run constitute additional burdens which, in the longer run, lead to new developments that leave people better off than if the problems had never arisen.This paper benefitted from being presented in earlier draft at a Population Association of America meeting, to the Economic History workshop at the University of Illinois, and to a seminar of the International Union for the Scientific Study of Population in New Delhi. We appreciate valuable comments on earlier drafts from Stanley Engerman, E. L. Jones, William McNeill, and two anonymous referees. Gunter Steinmann acknowledges financial support from the Volkswagen Foundation and a travel grant from Fulbright Commission.     

Calculating the total vote where the district magnitude is greater than one: A test of some algorithms using British local election data

Electoral analysis using aggregate data relies on the availability of accurate voting statistics. One vital piece of information, often missing from official electoral returns, particularly British local government elections, is the total number of valid ballot papers. This figure is essential for the calculation of electoral turnout. When voters have a single vote and official information about the number of ballot papers issued is missing, a figure for the total vote can still be derived. However, local elections in Britain frequently use a system of multiple-member wards, where voters have as many votes as there are seats to be filled. In such cases, calculating the total vote and, hence, the turnout does present a real problem. It cannot be assumed that all voters will use their full quota of votes or that voters will cast a ballot in favour of a single party. This paper develops and tests diff erent algorithms for calculating the total vote in such circumstances. We conclude that the accuracy of an algorithm is closely related to the structure of party competition. The findings of this paper have a number of important implications. First, the difficulties in calculating the turnout in multiple-member wards are identified. This will inform the debate about public participation in the local electoral process. Second, the method for deriving a figure for the total vote has an important bearing on a number of other statistics widely employed in electoral analysis.     

制造企业服务业务扩展及其认知因素研究

制造企业的竞争越来越激烈,几乎所有的企业都要面对快速反应多变市场和应对价格压力的要求,面对越来越小的产品利润空间和越来越复杂的客户需求,本文从对工业服务管理文献分析和制造企业的调查研究入手,揭示了制造企业从纯粹的产品生产者向客户支持方案提供者发展的转移趋势.通过对瑞士和德国30多家机器和设备制造企业进行的调查研究,说明了服务业务对制造企业在开发财务、营销和战略机会上的重要作用,并对转移过程中服务业务的扩展过程进行了总结.结合具体企业实践,本文对制约制造企业扩展服务业务中在管理动机上的认知因素进行了分析和研究.结合中国加入WTO后,中国制造企业将全面融入国际竞争的背景,本文期望对中国制造企业的发展和竞争地位的提高提供理论和实践上的指导.     

The effect of a novel ADL-based training program on performance of activities of daily living and physical fitness

The purpose of this study was to determine the degree to which a novel training program based on activities of daily living (ADL) would affect performance of ADLs, as well as the fitness of older adults. Fourteen individuals (mean age 82 years) took part in a 10-week control period followed by a 10-week ADL-based training program. Pre- and posttests included the Physical Performance Test (PPT), the Physical Functional Performance-10 (PFP-10), and the Senior Fitness Test (SFT). After the training period, improvements ranging from 7% to 33% (p<.05) were seen on the PPT and PFP-10 and on three items of the SFT. After conversion to standard scores, the magnitude of change in the PPT and the PFP10 was significantly greater (p<.05) than the magnitude of change in the SFT. These data support the idea that this novel ADL-based training program was able to facilitate improved performance of ADLs, as well as select measures of fitness among older adults.     

Governing Sleepiness: Somnolent Bodies, Discourse, and Liquid Modernity

This paper is an inquiry into how a new truth about sleepiness is being produced in a society increasingly organized around the primacy of expertise and its representation in print and visual media. Sleepiness originally described a benign, naturally occurring corporeal moment, a precursor to sleep. Increasingly, however, a new and disturbing meaning of somnolence is found in a juncture of medical and epidemiological research, social movements, and popular culture. Alongside the idea that sleepiness is a tranquil promise of repose is another, emerging truth. Sleepiness, we are told, is hazardous to self and others, and, importantly, it is each person's responsibility to resist this seductive call of the body. How, we ask, is a private, routinely occurring state of partial consciousness deprivatized, linked to public health vernaculars, and transformed into a reprobate condition? This alternative, disturbing truth about sleepiness is shown to be emerging from several disparate, seemingly unrelated caches of scientific studies, social movement literatures, magazines and newspapers, and web sites. The ideas of Michel Foucault, who pioneered the contemporary study of discourse, are shown to be particularly apropos to this inquiry, though not without some modification to make them more amenable to a contemporary society shaped increasingly by what Zygmunt Bauman calls “liquid modernity.”