Consideration of Background Exposures in the Management of Hazardous Waste Sites: A New Approach to Risk Assessment

The current approach to health risk assessment of toxic waste sites in the U.S. may lead to considerable expenditure of resources without any meaningful reduction in population exposure. Risk assessment methods used generally ignore background exposures and consider only incremental risk estimates for maximally exposed individuals. Such risk estimates do not address true public health risks to which background exposures also contribute. The purpose of this paper is to recommend a new approach to risk assessment and risk management concerning toxic waste sites. Under this new approach, which we have called public health risk assessment, chemical substances would be classified into a level of concern based on the potential health risks associated with typical national and regional background exposures. Site assessment would then be based on the level of concern for the particular pollutants involved and the potential contribution of site contaminants to typical background human exposures. While various problems can be foreseen with this approach, the key advantage is that resources would be allocated to reduce the most important sources of human exposure, and site remediation decisions could be simplified by focussing on exposure assessment rather than questionable risk extrapolations.     

Interrelationships between fertility and marital dissolution: Results of a simultaneous logit model

Previous studies have failed to examine (a) the simultaneity of decisions to bear children and to dissolve a marriage and (b) the effects of the childbearing in the period just before dissolution on the likelihood of disruption. We attempted to resolve both problems by developing a simultaneous logit model of the interrelationship between the probability of separation and of having a birth during this period (when dissolution presumably is being considered). The model was estimated at successive durations of first marriage, using data for white women in the 1970 National Fertility Survey. The results indicate that childbearing patterns— number of children and age of youngest child at the beginning of the marital interval being studied and fertility during the interval—did not influence the likelihood of separation in simple or consistent ways over the marital life course, nor did marital strife (as indicated by separation) seem to affect childbearing throughout marriage.     

Boards of directors in nonprofit organizations do they follow a life-cycle model?

In this study the authors used data from a survey of Canadian nonprofit organizations to empirically test hypotheses derived from models of nonprofit board “life cycles.” The authors suggest that while formal structural elements of board behavior change in the manner suggested by life-cycle models, the more enacted or behavioral aspects of nonprofit boards do not. The data further suggest caution in the use of life-cycle or age-dependent models to either explain or guide nonprofit board behavior.     

School-based interventions with depressed minority adolescents

School-based approaches to intervention with depressed minority adolescents is discussed within a preventive framework. The symptomatology and epidemiology of depression is presented as it pertains to minority group adolescents. Specific suggestions for school-based services, the uses of school-based mental health professionals, and for coordination with mental health agencies are provided.     

CONVERGENT SERIES EXPRESSIONS FOR INVERSE MOMENTS OF QUADRATIC FORMS IN NORMAL VARIABLES

Using relatively recent results from multivariate distribution theory, a direct approach to evaluating the inverse moments of a quadratic form in normal variables is proposed. Convergent infinite series expressions involving the invariant polynomials of matrix argument are obtained. The solution also depends upon a positive scalar which is arbitrarily chosen. For the solution to converge an upper bound upon this scalar is derived.     

Fathers in child welfare: caseworkers' perspectives

Five focus groups substantially agreed about the lack of paternal participation in child welfare services and the reasons for low paternal involvement. The groups had considerable disagreement about whether child welfare professionals should address this issue. Some caseworkers believed that all fathers and mothers should be treated identically with respect to services to be offered and time frames for services; other caseworkers thought that the special circumstances of some fathers, such as lack of child care experience, called for service approaches that differ from those for mothers. Another disagreement was whether more fathers would be more involved if services were gender sensitive, that is, if agencies provided male caseworkers for fathers and had father-only services. Much of the debate focused on pragmatic considerations (would gender-sensitive services improve paternal participation and outcomes?), although some participants were concerned about equity (would such services give fathers an advantage in disputed custody cases?).