Regression models for cyclic data

Summary. Geologists take slices through rock samples at a series of different orientations. Each slice is examined for a phenomenon which may occur in one of two states labelled clockwise and anticlockwise. The probability of an occurrence being in the clockwise state is dependent on the orientation. Motivated by these data, two models are presented that relate the probability of an event to orientation. Each model has two parameters, one identifying the orientation corresponding to the peak probability, and the other controlling the rate of change of probability with orientation. One model is a logistic model, whereas the other involves a power of the sine function. For the given data neither model consistently outperforms the other.     

How to reduce the risk of HIV infection for the seriously mentally ill.

1. The professional literature increasingly indicates the need to educate persons with serious mental illness regarding HIV/AIDS. 2. Community-based organizations currently responding to the AIDS epidemic are poorly equipped to respond to the special needs of persons with serious mental illness. 3. Persons with serious mental illness are concerned by HIV/AIDS. Some, however, will incorporate education into their pathology via delusional systems or misunderstandings. 4. Effective programs for this population can be developed following community health nursing principles.     

Contextual Factors in the Rise of Academic Sociology in the United States*

Cet article effectue l'analyse de certains elements culturels et educatifs qui favoriserent la croissance de la sociologie en tant que discipline universitaire aux Etats-Unis a la fin du dix-neuvieme siecle. II est a remarquer que cette evolution est unique au contexte americain. Les facteurs qui retiennent l'at-tention de l'auteur son les suivants: les attitudes vis-a-vis l'education superieure; rinfluence des ideaux et methodes allemands concernant l'education; la con-fiance que Ton avait dans la valeur de la science, y compris les sciences sociales; le climat ideologique liberal de la societe americaine et, par voie de consequence, des universites; et l'etat d'avancement de la theorie sociologique aux Etats-Unis durant cette periode. This paper is concerned with some of the cultural and educational elements in late nineteenth-century America which allowed for and fostered the ready growth of sociology as a university discipline at that time, a growth not to be found in other countries. Specific factors investigated are the attitude towards higher education, the influence of German ideals and methods on that education, the belief in the value of science, including social science, the liberal ideological climate of the society and hence of the universities, and the general state of sociological theory in the United States in this period.     

Failures of the reduction principle in an Ellsberg-type problem

Segal (1987) suggested that the Ellsberg paradox might be explained in terms of individuals mentally representing the decision problem as a two-stage lottery which they evaluated according to a non-expected utility model. This paper describes an experiment involving an explicitly two-stage analogue to an Ellsberg-type problem. This design substantially reduces the frequency of classic Ellsberg behaviour, but reveals other systematic violations of conventional theory. The paper discusses the particular patterns of choice and raises the more general problem of modelling individual decisions when the reduction principle does not hold.     

Is screening and brief advice for problem drinkers by clergy feasible? A survey of clergy

Routine screening for alcohol abuse in primary care, with brief advice to stop drinking for those screening positive, can detect individuals with alcohol problems and reduce alcohol use and alcohol induced problems in those detected. Not everyone with alcohol problems sees a physician regularly, however, and not all respond to a physician's brief advice. To explore the feasibility of expanding screening for alcohol problems to clergy, we did a mailed survey to 315 clergy at Christian churches in Cleveland, Ohio. Clergy reported a variety of views about alcohol use and abuse, but most agreed that alcoholism is a disease. They indicated counseling a significant number of parishioners, and were receptive to learning brief screening questions to detect alcohol problems. We conclude that many clergy would be interested in a strategy of screening and then giving brief advice or referral to individuals found to have alcohol problems.     

Condom discomfort and associated problems with their use among university students

In addition to consistent use, condoms must be used correctly. The purpose of this study was to identify prevalence and types of condom-associated discomfort among university students, the outcomes of this discomfort, and the role of discomfort in condom breakage. We conducted a cross-sectional study of 206 students attending a private university in the southern United States. We assessed 3 potential outcomes: breakage, not using condoms throughout sex, and low condom-use motivation. Nearly one third reported discomfort, including tightly fitting condoms, vaginal irritation, and loss of sensation. Discomfort was associated with breakage (p = .0001), incomplete use (p = .0001), and less motivation to use condoms (p = .018). Gender moderated the latter 2 findings. Adjusted findings indicate that students reporting discomfort were 3.6 times more likely to also report breakage (p = .0009). Continued investigation of this topic is warranted. Prevention education may benefit university students by promoting several key practices, such as adding lubricant to condoms before they dry out and acquiring condoms that fit properly.     

Predicting EPA''s Forthcoming CO Standards in Light of New Clinical Evidence

For the past several years, the EPA has been monitoring clinical studies on the adverse health effects of heart patients' exposure to carbon monoxide. This paper examines the impact of three such studies (including the multi-center CO study organized by the Health Effects Institute) on the forthcoming EPA standards for carbon monoxide. Eleven peer-nominated specialists with expertise in environmental science and public policy were interviewed according to a specific protocol. Overall, the experts felt that the HEI study would receive greater weight than the other two studies in the regulatory process for a variety of technical reasons. Weighting each expert opinion equally, we conclude that there is about a 0.69 probability that the CO standards will be retained at their present levels, a 0.28 probability that the standards will be tightened, and a 0.03 probability that the standards will be relaxed. When asked to imagine that the HEI data were never collected and then asked to reassess their probability judgments, the mean probability judgment that the standards will be relaxed rose to 0.11, while the mean probability judgment that the standards will be tightened fell to 0.20. A modest degree of variability in expert opinion is reported in the paper. While the HEI study may receive relatively great weight in the regulatory process, it increases only slightly the probability that EPA's CO standards will be changed.