Cancer Risk Assessment with Intermittent Exposure

Applications of methods for carcinogenic risk assessment often focus on estimating lifetime cancer risk. With intermittent or time-dependent exposures, lifetime risk is often approximated on the basis of a lifetime average daily dose (LADD). In this article, we show that there exists a lifetime equivalent constant dose (LECD) which leads to the same lifetime risk as the actual time-dependent exposure pattern. The ratio C = LECD/LADD then provides a measure of accuracy of risk estimates based on the LADD, as well as a basis for correcting such estimates. Theoretical results derived under the classical multistage model and the two-stage birth-death-mutation model suggest that the maximum value of C, which represents the factor by which the LADD may lead to underestimates of risk, will often lie in the range of 2- to 5-fold. The practical application of these results is illustrated in the case of astronauts subjected to relatively short-term exposure to volatile organics in a closed space station environment, and in the case of the ingestion of pesticide residues in food where consumption patterns vary with age.     

COURSEWORK AND SELF-STUDY IN THE FAMILY TREATMENT OF ALCOHOL AND DRUG ABUSE: EXPANDING HEATH AND ATKINSON'S CURRICULUM

In designing a course on the family treatment of alcohol and drug problems, a number of important issues and topics need to be addressed. A design by Heath and Atkinson (1988) provides an excellent, innovative model for such coverage. These authors, however, had to contend with certain constraints that have had a bearing on the course content and how it is taught. The present paper offers some revisions and alternatives to Heath and Atkinson's model in order to make it generalizable to a greater number of contexts. For clinicians who are less interested in teaching such a course, the two papers, combined, could serve as a guide for self-study in this area.     

Multinomial and conditional logit discrete-choice models in demography

Although discrete-choice statistical techniques have been used with increasing regularity in demographic analyses, McFadden's conditional logit model is less well known and seldom used. Conditional logit models are appropriate when the choice among alternatives is modeled as a function of the characteristics of the alternatives, rather than (or in addition to) the characteristics of the individual making the choice. We argue that this feature of conditional logit makes it more appropriate for estimating behavioral models. In this article, the conditional logit model is presented and compared with the more familiar multinomial logit model. The difference between the two techniques is illustrated with an analysis of the choice of marital and welfare status by divorced or separated women.     

INTEGRATING INDIVIDUAL AND SYSTEMS APPROACHES: STRATEGIC-BEHAVIORAL THERAPY

The existing literature on the integration of family and individual approaches, largely analytic in orientation, consists of models which, for the most part, are not brief in application. An alternative, brief model is presented which integrates an individual, cognitive-behavioral approach with a strategic approach at both pragmatic and theoretical levels. The Strategic-Behavioral model justifies the selective use of behavioral frames in strategic therapy and offers guidelines for their selective application.