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.     

Families and donor insemination: the views of semen donors

One of the consequences of donor insemination for the semen donor is that he becomes a member of two families: his own family in which he has a genetic and social connection with his offspring; and the family of the recipient couple, in which he has a genetic connection to the offspring, but usually no social connection with either the offspring or the recipient couple. This article challenges the dominant view that donor insemination as a practice of mainly medical or legal importance by looking at the attitudes of donors to both their own family and the family to which they have contributed their genetic material. Results are presented concerning who donors have told about their donation, who they think should be told, whether they think recipient couples should tell their donor insemination offspring about their conception, and concerning their opinions about factors that are considered in matching donors with recipient fathers.     

Least restrictive alternative: ethical considerations

Potential ethical dilemmas occur between rights and needs within the context of least restrictive alternative for psychiatric patients. This concept has been viewed primarily as a mechanism for limiting paternalistic interference and promoting individual dignity and autonomy. In addition, it has implied some possible conflicts in supporting such a well intentioned concept as least restrictive alternative without more reflection on the complexities involved.     

SPECULATIVE STORAGE, FUTURES MARKETS, AND THE STABILITY OF COMMODITY PRICES

A theoretical dynamic model is developed that integrates the micro-behavior of commodity and futures speculators into the simultaneous determination of cash and futures prices in a storable commodity market. The model is used to demonstrate the way in which the introduction of a futures market, by affecting the decisions of speculative inventory holders, alters the distribution of spot prices and to elucidate the conditions that render futures trading stabilizing for cash prices.     

The comparative analysis of the dynamics of childbearing women's birth at Yanging County, Beijing]

At the end of 1981 Yanging County had 26 communes, 375 production brigades and a total population of 211,098. A random sampling of 5.07% of the production brigades was taken, which included teams from the plains as well as mountainous regions. The sample had a population of 10,888, or 5.16% of the entire county, among whom 189 subjects were interviewed. These 189 women, whose ages ranged from 35-67, were divided into 5 birth year cohorts (1914, 1920, 1930, 1940, 1946). Findings include: 1) Age at marriage: the average age at marriage (about 17 years) between the 1914 and 1946 groups rose 1.82 years, indicating that early marriage was the norm. The time between marriage and 1st birth has shortened. 2) Fertility data: from 1914 to 1946 the lifetime fertility rate tended to decline from 4.60 to 3.70, but the 1930 cohort was the highest (6.42), followed by the 1920 cohort (6.26). The fertility rate of the 1914 cohort tended to rise in the 1950s after already having reached a peak in the early 1940s, probably because after Liberation fertility rose due to a higher standard of living and a stablized society. The fertility of the 1930 cohort was highest around 1963 when they were already 30 years old. The fertility of the 1940 cohort was also highest beginning around 1963. In both cases, the reason probably was because the national economy improved at this time. Indeed, the national fertility rate rose from a 1960 low of 20.9/1000 to 43.6/1000 in 1963. 3) Contraceptive use: prior to 1972 before there was an offical birth control policy, a sizeable number of women already desired to use contraceptives, the reason being most of these women felt they already had enough children. However, many women did use contraceptives in response to the call to do so. 4) Factors influencing fertility standards: in general, the less a woman's education and the lower her income, the higher was her standard of fertility, and vice versa. 5) The percentage of women who had children who died before the age of 15 ranged from 35.9% of the 67 year olds to 12.6% of the 35 year olds.     

Variations in carambola infestation rates byBactrocera carambolae drew and hancock (Diptera: Tephritidae) with fruit availability in a carambola orchard

The relationship between the infestation rate of carambola fruits byBactrocera carambolae Drew and Hancock was investigated in a carambola orchard. Phenology of the fruits was found to influence percentage infestation of fruits byB. carambolae. The proportion of unbagged or susceptible fruits infested varied with time of year and tended to decrease with the increase of unbagged fruits available on the tree. The number of ovipunctures per fruit varied with fruit size and was also found to be indicative of the number of adult insects (B. carambolae and parasitoids) that will emerge from each fruit. Higher number of susceptible fruits available on each tree also decreased both the number of ovipunctures per fruit and the number of eggs laid per fruit, which could possibly be due to the strategy of spreading the risk adopted by the femaleB. carambolae or a result of random selection with more hosts available. The main parasitoids recorded wereBiosteres vandenboschi (Fullaway) andB. arisanus (Sonan). The mean percentage of parasitism was 38.3% and it followed roughly that of infestation of fruits.