Is There a Quest for Identity?*

It is widely assumed that people today experience an imperative quest for identity, and that altruism and work have been displaced as credible routes to self-discovery by the abandonment of inhibition and the attainment of intimacy. A preliminary examination of these premises is made through questions included in a survey of adults in the Los Angeles metropolitan area and in questionnaires administered to students at UCLA, two Australian universities, and one British university. Very few adults in Los Angeles, even in the youngest and most highly educated brackets, acknowledge any preoccupation with the question, “Who am I really?,”though most university students in the four samples do. Both adults and students endorse altruism most frequently, impulse-release least frequently, and intimacy with intermediate frequency as routes to self-discovery. They differ most in their evaluation of work as a medium for self-discovery. All observations apply only to a self-conscious search for identity.     

Application of the user-centred design process according ISO 9241-210 in air traffic control

Designing a usable human machine interface for air traffic control is challenging and should follow approved methods. The ISO 9241-210 standard promises high usability of products by integrating future users and following an iterative process. This contribution describes the proceeding and first results of the analysis and application of ISO 9241-210 to develop a planning tool for air traffic controllers.     

Regression models for analyzing clustered binary and continuous outcomes under an assumption of exchangeability

Scientific experiments commonly result in clustered discrete and continuous data. Existing methods for analyzing such data include the use of quasi-likelihood procedures and generalized estimating equations to estimate marginal mean response parameters. In applications to areas such as developmental toxicity studies, where discrete and continuous measurements are recorded on each fetus, or clinical ophthalmologic trials, where different types of observations are made on each eye, the assumption that data within cluster are exchangeable is often very reasonable. We use this assumption to formulate fully parametric regression models for clusters of bivariate data with binary and continuous components. The regression models proposed have marginal interpretations and reproducible model structures. Tractable expressions for likelihood equations are derived and iterative schemes are given for computing efficient estimates (MLEs) of the marginal mean, correlations, variances and higher moments. We demonstrate the use the ‘exchangeable’ procedure with an application to a developmental toxicity study involving fetal weight and malformation data.     

OPTIMAL SAFETY-STOCK INVESTMENT THROUGH SUBJECTIVE EVALUATION OF STOCKOUT COSTS

This paper solves the problem of setting safety stocks by combining a subjective evaluation of the stockout-cost function with the usual holding-cost function. The technique given in this paper for estimating a decision maker's (DM's) disvalue function for stockouts is robust in terms of the shapes permissible for this function and allows for uncertainty on the part of the DM in expressing his/her trade-offs. The estimation technique could be applied to situations other than the safety-stock problem. We provide an optimization routine for the safety-stock problem which is designed to operate in conjunction with the estimation technique. Safety-stock levels are arrived at iteratively.     

Experimental Design of Bioassays for Screening and Low Dose Extrapolation

Relatively high doses of chemicals generally are employed in animal bioassays to detect potential carcinogens with relatively small numbers of animals. The problem investigated here is the development of experimental designs which are effective for high to low dose extrapolation for tumor incidence as well as for screening (detecting) carcinogens. Several experimental designs are compared over a wide range of different dose response curves. Linear extrapolation is used below the experimental data range to establish an upper bound on carcinogenic risk at low doses. The goal is to find experimental designs which minimize the upper bound on low dose risk estimates (i.e., maximize the allowable dose for a given level of risk). The maximum tolerated dose (MTD) is employed for screening purposes. Among the designs investigated, experiments with doses at the MTD, 1/2 MTD, 1/4 MTD, and controls generally provide relatively good data for low dose extrapolation with relatively good power for detecting carcinogens. For this design, equal numbers of animals per dose level perform as well as unequal allocations.     

Conceptual dimensions of crowding reconsidered

A recent and noteworthy facet of crowding research has been the exploration of the perception of high density/crowding experiences. A review of the methods and results of these investigations reveals considerable variation across studies on the dimensions of stimulus domain and selection, attention to intersubject differences, and approaches to interpreting results. The outputs of these studies do not appear as clearcut as has been suggested. It is hoped that the raising of these issues will result in more careful and fruitful research in this area. The links between conceptual crowding, situational variables, intrapersonal variables, and behavioral responses to high density/crowding are discussed.     

Correlates contributing to involvement in violent behaviors among young adults

The study examines the extent to which gender, personality attributes, household, community, and environmental factors are associated with violent behaviors in young adulthood. The authors present findings from a sample of 765 21-year-old individuals participating in a drug and delinquency prevention study. Personality attributes, opportunities, and social acceptability of antisocial behaviors were identified as accounting for gender differences and having more influence on violent behavior than environmental correlates. Implications for preventive intervention are discussed.     

Psychiatric emergencies: the check effect revisited.

Federal income support to persons with alcohol and drug related disabilities was ended in 1997. The argument for ending the programs was that recipients were using their benefits to purchase drugs and alcohol. This supposedly led to the "check effect," an increase in psychiatric emergencies in American communities in the days following the receipt of disability benefits. We test two hypotheses implied by this argument. The first is that psychiatric emergencies are elevated in the fourth through eighth day of the month. The second is that the excess of emergencies in these days was significantly reduced when benefits were ended. The tests are based on 35,500 psychiatric emergencies in San Francisco, California occurring over 1,551 days. Results support the first hypothesis but not the second. The implications are that there is a general check effect and that it was not reduced by ending benefits to persons with drug and alcohol related disabilities.