Combined Effects of Contaminant Desorption and Toxicity on Risk from PAH Contaminated Sediments

A strong inverse correlation was observed between the polycyclic aromatic hydrocarbon (PAH) mass fraction desorbed, a surrogate measure of bioavailability, and relative carcinogenicity, as quantified by potency equivalency factors (PEFs), for two study sediments from the New York/New Jersey Harbor estuary. Because compounds with the highest toxicity, such as dibenz(a,h)anthracene and benzo(a)pyrene (BAP), also tended to be the least rapidly and least extensively desorbed, the U.S. Environmental Protection Agency (EPA) default guidance may dramatically overestimate risk from exposure to PAH-contaminated soils or sediments. A "relative risk index" (RRI) was developed to account for the combined effects of compound-specific bioavailability and toxic potency in estimating excess cancer risk. Using this approach, estimated excess cancer risk may be diminished by as much as a factor of 159 times versus default EPA guidance. Also, the hierarchy of estimated risk between study sediments and among treatment fractions of study sediments differed using the two approaches, implying that the default approach may inaccurately determine site clean-up priorities. The percentage contribution of each potentially carcinogenic priority PAH to total excess cancer risk was computed under various scenarios. In each case, the contribution of BAP to total excess cancer risk was remarkably invariable, for example, ranging from 48% to 52% in one sediment, and 44% to 54% in the other, over four different exposure durations. These results suggest that BAP may be an excellent indexing compound for gauging relative exposure risk across sediments. Other important contributors to total excess cancer risk were benz(a)anthracene and dibenz(a,h)anthracene. Together, these three compounds comprised nearly 90% of total excess cancer risk from all PAHs in every scenario. This integrated RRI approach may enable regulators to more accurately gauge relative risks and make more informed sediment management decisions.     

Murine models of life span extension

Mice are excellent experimental models for genetic research and are being used to investigate the genetic component of organismal aging. Several mutant mice are known to possess defects in the growth hormone/insulin-like growth factor 1 (GH/IGF-1) neurohormonal pathway and exhibit dwarfism together with extended life span. Their phenotypes resemble those of mice subjected to caloric restriction. Targeted mutations that affect components of this pathway, including the GH receptor, p66Shc, and the IGF-1 receptor (IGF-1R), also extend life span; mutations that affect IGF-1R or downstream components of the pathway decouple longevity effects from dwarfism. These effects on life span may result from an increased capacity to resist oxidative damage.     

Tuberculosis screening on a health science campus: use of QuantiFERON-TB Gold Test for students and employees

Detecting and managing Mycobacterium tuberculosis (TB) infection in a health-science center population is a clinical dilemma. Tuberculin skin tests are still the preferred method for detecting present or past infection of TB. The authors discuss the performance of whole blood interferon gamma release assay test commercially known as QuantiFERON-TB Gold Test (QFT-G) as an additional tool for a TB surveillance program for the students and employees at an academic medical center. QFT-G was successfully implemented as a confirmatory test for screening of TB infection.     

In Sizing Civil Society,Wording and Format Matter

Social Indicators Research - For six decades the civil society and democracy thesis has generated great interest. How dependably can the relationship of associational membership to democracy be...     

Transport Policy Scenarios for the EU: 2020 Images of the Future

It is essential to take a longer term view if sustainable mobility is to become a reality. This paper takes a perspective to 2020 and constructs Images of the future which conform to the principles of sustainable mobility. Set at the EU level, clear environmental, regional development and efficiency targets are set, within which strategies are developed, based on different combinations of technological innovation and the decoupling of economic growth from transport growth. The external political situation is taken as given with either a move towards greater co-operation (and extension) or towards greater fragmentation (and regionalisaization) in Europe. The three Images of the future (2020) demonstrate that challenging targets for sustainable mobility can be achieved through a range of different policy actions within the transport sector and more widely. Immediate action is required and even more difficult choices will have to be made in the EU 15, if large-scale extension of the EU takes place. Improvements in vehicle technology alone will not achieve the targets. More fundamental changes have to take place in the way in which people make travel choices and in the means by which freight is transported. All of these measures must involve less travel, more efficient and cleaner travel modes.     

Dissecting the Conditions of Political Protest. An Exploration of Interaction Effects in the Explanation of Political Protest

This study addresses the conditions for the participation in protest activities. Starting from social psychological value expectancy theory and the theory of collective action, we study the effects of political discontent, perceived political influence (efficacy), norms to participate, identity, and membership in protest encouraging networks (“social incentives”) on protest. This study challenges the common assumption that these factors have additive effects only and provides a detailed analysis of interaction effects. Another contribution is the theoretical derivation of interaction effects. Our empirical analyses refer to the protests in Leipzig (East Germany) in 1989 under communist rule. Two‐way interactions are found between the following pairs of variables: discontent, influence, and norms. “Identity” (i.e., identification with West Germany) only interacts with discontent. Furthermore, identification is a surrogate for discontent: If identification is strong, discontent no longer influences protest. If identification is weak, increasing discontent raises protest.     

The Impact of Information Sharing on Supply Chain Performance under Asymmetric Information

The use of screening contracts is a common approach to solve supply chain coordination problems under asymmetric information. One main assumption in this context is that managers without specific incentives would rather use their private information strategically than reveal it truthfully. This harms supply chain performance. This study investigates the impact of information sharing in a principal‐agent setting that is typical for many supply chain transactions. We conduct a laboratory experiment to test whether information sharing has an influence on supply chain coordination. We find that information sharing within the supply chain has two positive effects. First, information sharing reduces the inefficiencies resulting from information deficits if there is a certain amount of trust in the supply chain. Second, communication can limit out‐of‐equilibrium behavior with a small impact on the firm's own payoff, but a large impact on the supply chain partner. Furthermore, we find that both effects are amplified when communication takes place in an environment that allows the less informed supply chain party to punish or to reward the better informed party. Although our extended mechanisms substantially enhance the poor performance of the theoretically optimal coordination contract menu, we find no mechanism that implements supply chain performance superior to the theoretically predicted second‐best level.