Cancer risk estimation for mixtures of coal tars and benzo(a)pyrene.

Two-year chronic bioassays were conducted by using B6C3F1 female mice fed several concentrations of two different mixtures of coal tars from manufactured gas waste sites or benzo(a)pyrene (BaP). The purpose of the study was to obtain estimates of cancer potency of coal tar mixtures, by using conventional regulatory methods, for use in manufactured gas waste site remediation. A secondary purpose was to investigate the validity of using the concentration of a single potent carcinogen, in this case benzo(a)pyrene, to estimate the relative risk for a coal tar mixture. The study has shown that BaP dominates the cancer risk when its concentration is greater than 6,300 ppm in the coal tar mixture. In this case the most sensitive tissue site is the forestomach. Using low-dose linear extrapolation, the lifetime cancer risk for humans is estimated to be: Risk < 1.03 x 10(-4) (ppm coal tar in total diet) + 240 x 10(-4) (ppm BaP in total diet), based on forestomach tumors. If the BaP concentration in the coal tar mixture is less than 6,300 ppm, the more likely case, then lung tumors provide the largest estimated upper limit of risk, Risk < 2.55 x 10(-4) (ppm coal tar in total diet), with no contribution of BaP to lung tumors. The upper limit of the cancer potency (slope factor) for lifetime oral exposure to benzo(a)pyrene is 1.2 x 10(-3) per microgram per kg body weight per day from this Good Laboratory Practice (GLP) study compared with the current value of 7.3 x 10(-3) per microgram per kg body weight per day listed in the U.S. EPA Integrated Risk Information System.     

A Simulation Study of Work-in-Process Inventory Drive Systems and their Effect on Operational Measurements

This simulation study compares three operational measures of performance through the exploration of three work-in-process (WIP) inventory drive systems and their associated inventory buffer characteristics. The three drive systems under study are a push, a pull and a hybrid push-pull system. While these systems have many aspects in common, their buffer management systems do not. The data analysis was based on information gathered from three computer-simulated flow shop assembly lines all operating in the same environment. Hypotheses concerning the operational performance measurements were established, independent variables were controlled and manipulated and a conclusion was drawn as to which system would afford the operation optimum results. While inventory has traditionally been considered and is currently being shown as an asset from an accounting point of view, it is obvious from the findings of this study, that excess WIP inventory, above the minimal requirements for production, may have a negative effect on the operational measurements evaluated.     

Professional Social Science: Responsible as Well as Respectable?

Acceptable professional behaviour for social scientists has strayed from traditional ideals. Among other reasons, the predominantly middle-class world view of most social science professionals has contributed to a narrow perspective on social matters which often leaves prevailing societal assumptions unchallenged. The emerging vision of a socially responsible role for social scientists calls into question many currently accepted aspects of professionalism, and the paper argues for a change of emphasis within social science to accommodate this new vision within the fold of professional respectability.     

The Stability of Social Groups in Childhood and Adolescence: The Role of the Classroom Social Environment.

This study provides a developmental analysis of childhood and adolescent social relationships within the school context. The social groups of 220 fourth graders and 475 seventh graders were tracked over a one year interval. The initial results indicated that approximately 30% of the social groups were identified as stable in that they maintained at least 50% of their membership over the one year interval. However, the stability in group affiliations was a function of the stability of the composition of the classroom. When schools did not promote classrooms as a unit, only 6.8% of social groups were stable, as compared to 55% of groups being stable when the school did promote classrooms as a unit. This school effect in group stability was demonstrated by a high correlation (rs = .97) between classroom stability and group stability. Even in unstable classrooms, individuals were more likely to maintain affiliations when group members were assigned to the same classroom. This work suggests that stable environments promote stable relationships, which in turn, may promote greater continuity in the organization of behavioral patterns.     

Hearing the voices of abused older women

This paper focuses on a qualitative research process that gathered responses from 64 older women aged fifty and older on their experience of violence and abuse. What older women said about abuse in their lives supports the use of a feminist framework as well as the age based analysis of the elder abuse field. Some respondents spoke of abuse from childhood into their later years. Some spoke of partners witnessing or experiencing abuse as children. Some women express concern about possible abuse by their adult children of their own children. Abused older women like younger women need a safe environment, emotional support, advocacy, information, and peer support. While it is important to consider the perspectives and knowledge of service providers when developing policy and practice on abuse of older women, it is critical to ask the women survivors of abuse or neglect what they believe would benefit them, and others in similar situations.     

Learning about radon's risk

This article reports the results of an evaluation of the effectiveness of different types of information materials in communicating the risk from exposure to radon, a naturally occurring indoor air pollutant. The study involved a panel of 2300 homeowners who actually experienced risks from radon, and the information program used to explain these risks. The analysis considered information transfer and performance on specific tasks requiring information on the risk from radon to measure learning. The results suggest a systematic learning process, but indicate that the process can be influenced by how risk information is presented.     

The Proportion of Gaming Revenue Derived from Problem Gamblers: Examining the Issues in a Canadian Context

The legitimacy of government-sponsored gambling and its continued expansion depends in part on the impact that gambling has on society and the extent to which gambling revenue is derived from vulnerable individuals. The purpose of the present article is to try to establish a valid estimate of the proportion of gaming revenue derived from problem gamblers in Canada. Using recent secondary data collected in eight Canadian provinces, we estimate this proportion to be 23.1%, compared to a problem gambling prevalence rate of 4.2%. This estimate must be seen as tentative, however, as self-reported expenditures are 2.1 times higher than actual provincial gaming revenues.     

Educational inequality across three generations in Australia

The transfer of advantage and disadvantage across multiple generations is receiving increasing attention in the international literature; however, transfers of resources across multiple generations in Australian families are less well understood. Using a longitudinal dataset of Australian children, we have the opportunity to not only investigate the transfer of educational resources across three generations in Australia, but also investigate the gendered nature of these transfers, which has been a limitation of other studies. We find no evidence of individual grandparent education effects on numeracy and reading scores for grandchildren in Year 3, independent of parent educational attainment and other covariates. However, significant effects on numeracy and reading scores were observed for children in families where both the grandmother and grandfather in maternal and paternal grandparent sets had high educational attainment (a diploma or university qualification), and where either or both the mother and father had a university qualification. These results suggest that the contribution of grandparents to the academic achievement of grandchildren cannot be fully explained by the parent generation and that the concentration of human capital in families contributes to educational inequalities across multiple generations that can be observed by eight years of age.