Parameter estimates from mark-recapture experiments on two populations subject to migration and death

Summary A model is developed for a triple catch marking experiment on two areas with migration between the two areas and death or emigration occurring. Estimates of the parameters of the model are derived. Some of these estimates are shown to be suitable even under certain restrictions on migration (e.g. animals may be restricted to a single transfer in the course of the experiment). Variances of the estimates were not derived but some rules were developed, based on computer simulations, to guide the experimenter in planning experiments and in judging the precision of his estimates.     

Sex selection with biased technologies and its effect on the population sex ratio

Current biomedical research on sex selection techniques may soon offer couples the opportunity to choose the sex of their children with greater certainty. A technique planned for marketing by mid-1978 can increase the probability of bearing a son to as much as 0.90. However, couples who wish to improve their chances of bearing a daughter have no such opportunity. The purpose of this paper is two-fold. First, a decision-making model is provided which describes how couples should choose among alternative sex-selection methods so as to maximize the probability of bearing their desired number of sons and daughters. Second, the effect of the widespread use of sex-selection techniques on the population sex ratio is explored. It is shown that even if populations have unbiased sex preferences, or sex preferences biased towards daughters, the use of biased sex-selection technologies may result in very high population sex ratios.     

Medical foster care for seriously medically ill children: A growing need

This article identifies and lists the problems of children with complex medical conditions and/or complex home health case needs. Five categories of seriously chronically ill children are identified and programs to meet their needs discussed. The authors believe many of these children could benefit from foster home placements; they discuss one project in which there is collaboration between a pediatric medical center and a social service agency.     

THE GANDHI TECHNIQUE: A NEW PROCEDURE FOR INTRACTABLE PROBLEMS

Most therapists eventually encounter a client with intractable difficulties. Such difficulties have various origins. The Gandhi Technique is a simple, dramatic and seemingly effective procedure to resolve intractable difficulties. This paper describes the technique and its application in three different cases. The paper also discusses several theories which may account for the efficacy of the technique. The authors propose the technique as a procedure that can be employed to resolve many kinds of problems, regardless of their origin.     

Dwelling Space: Expectations and the Housing System

The average person-per-room ratio in Australia is low by international standards. But there are marked inequalities in the distribution of dwelling space, and the question is examined of whether the current allocation of dwelling space within the housing system constitutes a social problem on a national scale. The examination is based partly on an analysis of published census data, partly on existing literature, and partly on raw data derived from two recent housing surveys.     

A Stimulus Control Model of Change in Behavioral Couples' Therapy: Implications for Contingency Contracting

Although contingency contracting is a popular strategy for use in treating distressed relationships, there is no direct evidence of its efficacy. A stimulus control model of change in behavioral couples' therapy states that the conditions under which an agreement was negotiated, regardless of the consequences specified in the agreement itself, are the primary determinants of whether the agreement is upheld. Once change is prompted, its maintenance is associated with stimuli generated by the negotiating session itself (that is, self-statements) and contingencies provided by concurrent changes occurring in therapy. Therefore, it is argued that explicit contingency contracting is unnecessary, and in fact contraindicated, for reasons which are elaborated. Hypotheses are offered which provide indirect tests of this model of change in behavioral couples' therapy .