Regression analysis for discrete event history or failure time data

The paper deals with discrete-time regression models to analyze multistate—multiepisode models for event history data or failure time data collected in follow-up studies, retrospective studies, or longitudinal panels. The models are applicable if the events are not dated exactly but only a time interval is recorded. The models include individual specific parameters to account for unobserved heterogeneity. The explantory variables may be time-varying and random with distributions depending on the observed history of the process. Different estimation procedures are considered: Estimation of structural as well as individual specific parameters by maximization of a joint likelihood function, estimation of the structural parameters by maximization of a conditional likelihood function conditioning on a set of sufficient statistics for the individual specific parameters, and estimation of the structural parameters by maximization of a marginal likelihood function assuming that the individual specific parameters follow a distribution. The advantages and limitations of the different approaches are discussed.     

An Enforceable Indoor Air Quality Standard for Environmental Tobacco Smoke in the Workplace1

Environmental tobacco smoke (ETS)has recently been determined by U.S. environmental and occupational health authorities to be a human carcinogen. We develop a model which permits using atmospheric nicotine measurements to estimate nonsmokers’ETS lung cancer risks in individual workplaces for the first time. We estimate that during the 1980s, the U.S. nonsmoking adult population's median nicotine lung exposure (homes and workplaces combined)was 143 micrograms (μg)of nicotine daily, and that most-exposed adult nonsmokers inhaled 1430 μg/day. These exposure estimates are validated by pharmacokinetic modeling which yields the corresponding steady-state dose of the nicotine metabolite, cotinine. For U.S. adult nonsmokers of working age, we estimate median cotinine values of about 1.0 nanogram per milliliter (ng/ml)in plasma, and 6.2 ng/ml in urine; for most-exposed nonsmokers, we estimate cotinine concentrations of about 10 ng/ml in plasma and 62 ng/ml in urine. These values are consistent to within 15% of the cotinine values observed in contemporaneous clinical epidemiological studies. Corresponding median risk from ETS exposure in U.S. nonsmokers during the 1980s is estimated at about two lung cancer deaths (LCDs)per 1000 at risk, and for most-exposed nonsmokers, about two LCDs per 100. Risks abroad appear similar. Modeling of the lung cancer mortality risk from passive smoking suggests that de minimis [i.e., “acceptable” (10^-6)], risk occurs at an 8-hr time-weighted-average exposure concentration of 7.5 nanograms of ETS nicotine per cubic meter of workplace air for a working lifetime of 40 years. This model is based upon a linear exposure-response relationship validated by physical, clinical, and epidemiological data. From available data, it appears that workplaces without effective smoking policies considerably exceed this de minimis risk standard. For a substantial fraction of the 59 million nonsmoking workers in the U.S., current workplace exposure to ETS also appears to pose risks exceeding the de manifestos risk level above which carcinogens are strictly regulated by the federal government.     

Organization of the planning department in a divisionalized concern

This article is based upon an assignment carried out by the author concerned with organization for planning in a company formed as a result of a merger. Possible organizational solutions are discussed and the recommendations of the author and his colleague outlined.     

Recent Immigrant Settlement in the Nonmetropolitan United States: Evidence from Internal Census Data*

Abstract In the 1990s, studies have documented widespread growth of immigrants in U.S. communities not known as common destinations in the past. This trend has fueled population growth in some nonmetropolitan areas and offset population decline in other areas. In this paper, we examine the implications of recent foreign born in-migration for rural America. Our focus is on a collection of 59 nonmetropolitan counties where growth in foreign born stock offset declines in U.S. native population and resulted in increased local population by 2000. To understand these nonmetropolitan offset counties, we use confidential Census Bureau data that offer us the detailed geography and larger sample size needed to closely examine spatial shifts in the foreign born population, especially those recently arrived. Our findings illustrate dramatic compositional shifts in the populations of these areas, and suggest new demographic complexity in nonmetropolitan areas in the 21^st century.     

Working around the Barriers to Creating and Sharing Knowledge in Capital Goods Projects: the Client's Perspective*

The article considers knowledge management issues from the client's perspective. In the example presented, a sludge treatment centre procured by Northumbrian Water Ltd (NWL), the task faced by the client was to manage knowledge in a context where the core technology being procured was new and resulted in the need for new knowledge to be created and shared both pre‐ and post‐delivery. In exploring these issues, the article reveals the problems of (and some solutions to) managing knowledge across the project life‐cycle and between different groups, where the motivation for generating and sharing knowledge was not the same for all participants.     

Activist online resource mobilization: Relationship building features that fulfill resource dependencies

This study examined activist group websites (N = 300) to determine how activists are engaging in resource mobilization online and provides a benchmark for current mobilization practices by activists. Website features asking visitors to donate, join the organization, and links to other activist groups were most common on the sites. The study positions resource mobilization in terms of online relationships and organizational linkages, argues that resource dependencies drive mobilization efforts and that resource-based relationships with publics may be established in the mobilization process.     

Repression and other Forms of Cognitive Evasiveness: Implications for Stress Symptoms in College Students

Abstract

Lazarus has proposed that palliative defenses against threat that interfere with direct efforts to alleviate the threat may prove maladaptive. Three evasive cognitive attributes that circumvent awareness of threat were studied to determine whether they related to the prevalence of stress symptoms in college students. Repression (selective forgetting of threatening material), awareness of the repressive defense, and internal scanning (breadth of association to cues) were considered. College students of both sexes who engaged in evasive cognitive activity reported more stress symptoms than those who did not, with a progressive increase in stress as increasingly homogeneous groups were considered. Students who defended themselves by repression experienced more stress than those who did not. Repressors who were the least aware of their use of this defense reported even more stress. Unconscious repressors who were the least reflective (narrow scanners) showed the highest frequency of stress symptoms.