Comparative risk assessment: an international comparison of methodologies and results

Comparative risk assessment (CRA) is a systematic procedure for evaluating the environmental problems affecting a geographic area. This paper looks beyond the U.S. border and examines the experience with CRAs conducted in various developing countries and economies in transition, including Bangkok, Thailand, Cairo, Egypt and Quito, Ecuador, as well as other locations in Eastern Europe, Asia and Central and South America. A recent pilot CRA conducted in Taiwan is also considered. Comparisons are made of both the methodologies and the results across the relatively diverse international literature. The most robust finding is that conventional air pollutants (e.g., particulate matter and lead) consistently rank as high health risks across all of the CRAs examined. Given the varied nature of the settings studied in the CRAs, including level of economic development, urban-rural differences, and climate, this finding is particularly significant. Problems involving drinking water are also ranked as a high or medium health risk in almost all the countries studied. This is consistent with the results of analyses conducted by the World Bank suggesting contamination, limited coverage and erratic service by water supply systems.Beyond the major air pollutants and drinking water, the CRA results diverge significantly across countries. A number of problems involving toxic chemicals, e. g., hazardous air pollutants, rank as high health risks in the US but do not appear as consistent areas of concerns in the other countries studied. This likely reflects the so-called "risk transition" - the shift from sanitation and infection disease problems to those involving industry, vehicles and toxic substances - that often occurs with economic development. It may also reflect the greater information about sources of toxic pollutants in the U.S. For other problems, there are important differences across the developing countries and economies in transition. For example, hazardous and (industrial) non-hazardous waste issues ranked as medium or low health risks in all the countries studied, except for Taiwan where unmanaged toxic waste sites were considered to pose high risks. While the generally low ranking is consistent with the notion that few people are directly exposed to hazardous and (industrial) non-hazardous waste, it is not entirely surprising that views might be different in Taiwan, where space is so limited and population density is so high.We suggest that the wide range of findings likely reflect genuine differences among the countries studied. However, we cannot entirely rule out the possibility that some of the observed similarities (and differences) arise from the (relatively) common methodologies employed.     

Studies in early infant learning: Classical conditioning of the neonatal heart rate.

Three experiments demonstrated that human newborn heart rate level can be reliably modified through classical conditioning procedures. The theory of sensitization served as a frame of reference for Exps I and II, and drive reduction served for Exp III. In Exp I the delay, delay-trace, and control groups, with 10 2-day-old newborns in each, received 5 preconditioning trials of the CS alone, 16 conditioning trials with CS–UCS pairings differing for each group, and 5 extinction trials. Exp II was a replication of the 1st study and involved only the delay and delay-trace groups with 10 infants each. In both studies the delay group curves showed significant monophasic acceleratory responses during extinction. Results support the sensitization hypothesis (i.e., the CR occurring in the interstimulus interval was fashioned out of the response to the CS). In Exp III, the measure of conditioning was the response to the probe technique. 10 experimental Ss received preconditioning trials of nitrogen puff (UCS?) administered to the abdomen, followed by 10 CS–UCS? (500-Hz tone acetic acid) pairings with an interstimulus interval of 3 sec. 10 controls received the same design with a CS–UCS? interval of 40 sec. Analyses of the probe stimulus trials showed significant changes for the control group and none for the experimental group. The CS–UCS? pairings in the experimental group are interpreted as producing increased drive and adaptive damping of the heart rate response. Findings show that early learning may occur under a variety of conditions and that the results can be incorporated by different theories. (79 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Korrosion durch Biokraftstoffe – Schutz durch Beschichtungen auch bei zyklischer Beanspruchung

Corrosion by biofuels ‐ Protection by coatings also under cyclic loadings The influence of corrosion on fatigue design must be considered in numerous component parts in the automotive industry. By using appropriate coatings the negative influence of corrosion under static and cyclic loading can be suppressed. Using the aluminum cast alloy AlSi7Mg0,3 T6 as an example, selected material‐coating‐systems were to be characterized under mechanical‐thermal‐corrosive complex loadings and characteristic properties for the fatigue design under cyclic loadings were to be determined. Conditioning tests were carried out with uncoated, anodized and chemical‐nickel‐plated specimen at different temperatures in the media fuel E5 (fuel with 5 % ethanol added) and E10 (fuel with 10 % ethanol added) and followed by SEM examined. The cyclic fatigue tests with chemically‐nickel‐plated and tempered aluminum in the fuel E5 at 100 °C no reduced influence on the fatigue strength, within the scattering, was discerned. This result agrees with the conditioning tests in the fuel E5 at 100 °C, where no corrosion was observed. Despite the coating of the specimens salt spray fog leads to a clear reduction in the fatigue strength. Using a damage accumulation calculation, it could be shown, that the real damage sum of the callipers and specimens, despite different types of coating, are comparable.     

Heat metering: socio-technical challenges in district-heated social housing

Individual heat metering and charging (IMC) are seen as promising methods to reduce domestic heating and hot water use through the provision of financial incentives. The heat consumption measured by meters is influenced by both the dwelling characteristics and the behaviour of the occupant, but heating charges would ideally relate to occupant behaviour only. This dilemma can be especially relevant under two circumstances: if the thermal performance of the dwelling is poor and/or if heating costs represent a substantial part of the occupants' income, i.e. in social housing. The case of a district-heated council block in London is presented where the installation of individual heat meters was planned in 2010 but had to be suspended due to concerns about implications for occupant heating costs in light of the thermal performance of the building. It illustrates a technically and socially complex environment where fairness in allocating heating costs is an important concern. The case also shows how lack of funding or other issues on the infrastructure side can hinder behaviour-orientated measures such as IMC. A holistic energy conservation strategy addressing both physical building properties and occupant behaviour is therefore essential and should be supported by policy.     

The role of oral processing in dynamic sensory perception

Food oral processing is not only important for the ingestion and digestion of food, but also plays an important role in the perception of texture and flavor. This overall sensory perception is dynamic and occurs during all stages of oral processing. However, the relationships between oral operations and sensory perception are not yet fully understood. This article reviews recent progress and research findings on oral food processing, with a focus on the dynamic character of sensory perception of solid foods. The reviewed studies are discussed in terms of both physiology and food properties, and cover first bite, mastication, and swallowing. Little is known about the dynamics of texture and flavor perception during mastication and the importance on overall perception. Novel approaches use time intensity and temporal dominance techniques, and these will be valuable tools for future research on the dynamics of texture and flavor perception.     

The Weathering Behavior of Heavy Metals in Ore Processing Residues (Mansfeld Region,Germany)

One of the ore processing residues in the Mansfeld region of Germany is a flue dust, which was scrubbed out of the smelter process gases by spraying water into the hot gas stream. During the many years of ore processing, the resulting fine-grained sludge was washed into ponds for storage. These sludge deposits were covered by water and thus sealed off from the atmosphere. However, after the local copper works shut down in 1990, the ponds dried up, causing the sludge in the uppermost layers to oxidize. The need to assess the risk posed by these deposits today prompted questions over the depth to which the dried sludge can be altered by weathering and the extent of heavy metal emissions. A drill hole was bored at the center of a dry pond and the core samples analyzed. The samples indicated relatively constant levels of Cu and Pb with depth, but other metals, such as Cd, Mn, and Zn, were relatively depleted in the upper 50 cm of the sludge body. Such behavior can be explained by the solubilities of the respective secondary phases. It appears that the oxidation of metal sulfides and the subsequent dissolution of the respective secondary phases, especially sulfates, pose a potential problem for the quality of the nearby ground and surface water.     

Magnetic resonance angiography demonstrates vascular healing of carotid and vertebral artery dissections

BACKGROUND AND PURPOSE: Dissection of the carotid and vertebral arteries is most accurately diagnosed with conventional angiography. MR techniques are sensitive for detecting the abnormalities associated with dissection but may lack specificity. We hypothesized that MR may be useful for serial monitoring of dissection and may therefore guide therapy. METHODS: All patients with angiographically proven carotid and/or vertebral artery dissection from July 1994 to June 1996 were followed for a median duration of 10.5 months. Of these 29 patients (44 vessels), 18 were concurrently evaluated with MR, and a target group of 9 patients (17 vessels) was prospectively followed with MR at 3-month intervals. RESULTS: In the 18 patients with both imaging studies at baseline, angiography revealed 30 dissected vessels while MR detected 27 (90%). In the target group of 9 patients, initial MR identified 15 of the 17 dissections diagnosed with angiography. Serial MR revealed complete healing in 5 vessels, improvement in 6 vessels, no change in 4 vessels, and worsening in 2 vessels. The radiographic features most likely to resolve were stenosis and mural hematoma, while occlusion and luminal irregularity tended to persist. Late ischemic events occurred in 2 patients, both with persistent MR evidence of dissection, one while subtherapeutic on warfarin therapy and the other occurring 1 week after warfarin was discontinued. CONCLUSIONS: MR is a reliable noninvasive method for following the vascular response to treatment and may guide the course of a clinical trial comparing medical therapies for carotid and vertebral artery dissection.     

Interaction of human leukotriene C4 synthase and microsomal glutathione transferase in vivo

Microsomal glutathione transferase (mGT) specifically binds leukotriene C4 synthase in the presence of Mg2+ ion (S?derstr?m et al., Protein Expression and Purification (1995) 6, 352-356). To investigate if this interaction occurs in vivo we screened a human lung cDNA library with a bait vector encoding human mGT in the yeast two-hybrid system. One of the five positive clones obtained encoded leukotriene C4 synthase. This clone was expressed in two heterologous systems. The recombinant protein cross-reacted with a guinea pig antibody raised against a Keyhole limpet hemocyanin coupled synthetic peptide corresponding to amino acids 141-150 of human leukotriene C4 synthase.