Reproductive and Developmental Risks from Ethylene Oxide: A Probabilistic Characterization of Possible Regulatory Thresholds

Ethylene oxide is a gas produced in large quantities in the United States that is used primarily as a chemical intermediate in the production of ethylene glycol, propylene glycol, non-ionic surfactants, ethanolamines, glycol ethers, and other chemicals. It has been well established that ethylene oxide can induce cancer, genetic, reproductive and developmental, and acute health effects in animals. The U.S. Environmental Protection Agency is currently developing both a cancer potency factor and a reference concentration (RfC) for ethylene oxide. This study used the rich database on the reproductive and developmental effects of ethylene oxide to develop a probabilistic characterization of possible regulatory thresholds for ethylene oxide. This analysis was based on the standard regulatory approach for noncancer risk assessment, but involved several innovative elements, such as: (1) the use of advanced statistical methods to account for correlations in developmental outcomes among littermates and allow for simultaneous control of covariates (such as litter size); (2) the application of a probabilistic approach for characterizing the uncertainty in extrapolating the animal results to humans; and (3) the use of a quantitative approach to account for the variation in heterogeneity among the human population. This article presents several classes of results, including: (1) probabilistic characterizations of ED10s for two quantal reproductive outcomes-resorption and fetal death, (2) probabilistic characterizations of one developmental outcome-the dose expected to yield a 5% reduction in fetal (or pup) weight, (3) estimates of the RfCs that would result from using these values in the standard regulatory approach for noncancer risk assessment, and (4) a probabilistic characterization of the level of ethylene oxide exposure that would be expected to yield a 1/1,000 increase in the risk of reproductive or developmental outcomes in exposed human populations.     

Business drivers not sector membership determine the most effective production planning and control; a novel approach to a perennial problem

This paper outlines research aimed at developing novel planning and scheduling reference models for industrial sectors where the MRPII paradigm is not appropriate. It outlines the process mapping approach adopted, the data capture method developed for the case study companies, the use of ARIS (Scheer's) enterprise modelling tool, and the first stages in the production of sector reference models.     

Managerial manpower planning— A systematic approach

At what ages should managers be recruited? Are the young managers receiving the right sort of experience at an early stage in their careers? What effect will the proposed merger have on the career prospects in the company.....? Questions such as these are likely to face every company from time to time, but finding the answers can be very difficult. The task may be made much easier through the application of some simple analytical techniques. These techniques are discussed here in the form of a case study.     

Seat belt laws: why we should keep them

In the June 2007 issue of Significance , John Adams argued for the repeal of seat belt laws. They have never been demonstrated to save lives, he said; and they increase the number of pedestrians and cyclists killed on the roads. Richard Allsop, Oliver Carsten, Andrew Evans and Robert Gifford argue that Parliament should keep the seat belt laws on the statute book and that we should all keep wearing belts whenever we travel in a car, van or coach—and they contest John's statistics.     

Moments of Inertia and Graph Separators

Graphs that arise from the finite element or finite difference methods often include geometric information such as the coordinates of the nodes of the graph. The geometric separator algorithm of Miller, Teng, Thurston, and Vavasis uses some of the available geometric information to find small node separators of graphs. The algorithm utilizes a random sampling technique based on the uniform distribution to find a good separator. We show that sampling from an elliptic distribution based on the inertia matrix of the graph can significantly improve the quality of the separator. More generally, given a cost function f on the unit d-sphere Ud, we can define an elliptic distribution based on the second moments of f. The expectation of f with respect to the elliptic distribution is less than or equal to the expectation with respect to the uniform distribution, with equality only in degenerate cases. We also demonstrate experimentally that the benefit gained by the use of the additional geometric information is significant. Some previous algorithms have used the moments of inertia heuristically, and suffer from extremely poor worst case performance. This is the first result, to our knowledge, that incorporates the moments of inertia into a provably good strategy.     

The Multicultural Welfare State: International Experience and North American Narratives

Contemporary debates are increasingly pessimistic about the impact of ethnic diversity on support for the welfare state. A growing number of analysts argue that greater ethnic diversity in Western democracies is weakening public support for redistribution, and that this underlying tension is exacerbated by the adoption of robust multiculturalism policies. The purpose of this essay is to summarize early findings from several studies that bear on the questions at the heart of such debates. These studies analyse the implications of immigration and multiculturalism policies for the welfare state across OECD countries, and also focus more closely on the experience of two distinctively multicultural countries, the United States and Canada. The evidence points to more complex relationships than often assumed. OECD countries with large foreign‐born populations have not had more difficulty in sustaining their welfare states than other countries. The extent of change does seem to matter, however, as countries in which immigrant communities grew rapidly between 1970 and the late 1990s did experience lower rates of growth in social spending. But despite the warnings of some critics, robust multiculturalism policies do not systematically exacerbate this tension. Moreover, the United States and Canada reflect different patterns. In the US racial diversity does weaken support for redistribution; but Canadian experience suggests that immigration, multiculturalism policies and redistribution can represent a stable political equilibrium. These contrasting narratives from North America stand as a warning against premature conclusions based on the US experience alone. There is no inevitability at work, and policy choices do seem to matter.     

Whom can you trust? The politics of ‘grassing’ on an inner city housing estate

This paper derives from an ongoing research project concerned to explore how people living in, going to work in, attending school in, high crime areas manage their routine daily lives. It focuses on one of our research areas in which we argue that the question of the 'fear of crime' is much better understood through an appreciation of how the question of trust manifests itself in that community. In other words, whom you trust, when, and by how much, mediate the way in which people living in this area manage their routine daily lives and within that their sense of security.