An Analysis of Damage to U.S. Soybean Yields from 1982 Acid Deposition Levels

Experimental data were compiled for seven soybean varieties studied at four different locations in the U.S. for a period of one to three years. Three dose–response functions (linear, quadratic, and Weibull) were fitted, as appropriate, to the experimental data. Effects of acid deposition on soybean yields were estimated by combining variety-specific dose–response and production data. These calculations suggest that U.S. soybean production (2.2 billion bushels in 1982) would increase by 3.2 million bushels with a 10% reduction in 1982 hydrogen ion concentration levels in all counties where soybeans were grown, and by almost 70 million bushels with uniform improvement to pH 5.2. These estimates are based on many simplifying assumptions and are subject to several important sources of uncertainty explored in this study. The calculated changes are small in comparison with effects from other natural and anthropogenic stresses.     

Using the Biological Two-Stage Model to Assess Risk from Short-Term Exposures

Two assumptions used in risk assessment are investigated: (1) the assumption of fraction of lifetime dose rate assumes that the risk from a fractional lifetime exposure at a given dose rate is equal to the risk from full lifetime exposure at that same fraction of the given dose rate; (2) the assumption of fraction of lifetime risk assumes that the risk from a fractional lifetime exposure at a given dose rate is equal to that same fraction of the risk from full lifetime exposure at the same dose rate. These two assumptions are equivalent when risk is a linear function of dose. Thus both can be thought of as generalizations of the assumption that cancer risk is proportional to the total accumulated lifetime dose (or average daily dose), which is often made to assess the risk from short-term exposures. In this paper, the age-specific cumulative hazard functions are derived using the two-stage model developed by Moolgavkar, Venzon, and Knudson for situations when the exposure occurs during a single period or a single instant. The two assumptions described above are examined for three types of carcinogens, initiator, completer, and promoter, in the context of the model. For initiator and completer, these two assumptions are equivalent in the low-dose region; for a promoter, using the fraction of lifetime risk assumption is generally more conservative than that of the fraction of lifetime dose rate assumption. Tables are constructed to show that the use of either the fraction of lifetime dose rate assumption or the fraction lifetime risk assumption can both underestimate and overestimate the true risk for the three types of carcinogens.     

Analyzing birth intervals: Implications for demographic theory and data collection

In the last decade, the study of birth intervals has been greatly facilitated by a rapid expansion in data availability and by improvements in analytical techniques. Unfortunately, the results emerging from individual level, empirical studies of birth interval dynamics do not correspond with the predictions of standard demographic theory. This paper reviews a series of individual level studies that find substantial socioeconomic variation in childspacing after controlling statistically for the major intermediate or proximate variables. It then offers possible explanations for the lack of fit between theory and results at the micro level, concluding that the two most likely explanations are poor measurement of the four principal proximate determinants and the exclusion of additional proximate determinants.     

Factors that affect a victim's self-disclosure in father-daughter incest

Out of concern about the underreporting of father-daughter incest, the author has conducted a study in Virginia to test certain observations in the literature about the relatively small number of cases that come to light voluntarily. The findings point clearly to contributory case characteristics that can sensitize practitioners to the possibility of undisclosed incest.     

Conflicts, Conciliation and Social Work

Correspondence to Adrian L. James, Lecturer in Applied Social Studies, Department of Social Policy and Professional Studies, University of Hull, Cottingham Road, Hull HU6 7RX. Summary This article seeks to draw together some issues and themes whichare identifiable in recent social work literature and practice,and in the criminal and civil law. It explores the nature ofconciliation as a method for dealing with conflict. It alsoconsiders some aspects of the nature of social work and theprocess by which problems become the object of social work treatment.It is argued that this process can effectively limit the scopefor client involvement in seeking solutions to their problems,and that conciliation might offer some potential for increasingthis, whilst also revitalizing the ethical base of social workpractice.     

A longitudinal examination of the membership patterns of minorities and women in referral unions

In an examination of the membership patterns of minorities and women in building and nonbuilding trade referral unions between 1969 and 1979, results reveal that variations in referral union membership can be substantially accounted for by race and sex. Longitudinally, no meaningful changes in the racial composition of referral unions exist, while the sexual composition within building and nonbuilding trade union categories change significantly over time. More importantly, however, male / female representation patterns across both referral union categories over the ten-year period remain fairly constant relative to one another.