Gafchromic film as a fast visual indicator of radiation exposure of first responders

Three types of Gafchromic films have been studied to investigate their potential for use as a visually readable dosemeter for persons acting as first responders in connection with radiological or nuclear emergencies. The two most sensitive film types show a pronounced variation in sensitivity by photon energy and are therefore not suitable for use in cases of unknown exposures. The third film type tested (RTQA2), which is intended for quality control in radiation therapy has a sensitivity that is independent of the radiation quality, and is therefore considered as the most optimal for visual reading in situ. Tests carried out on a group of 10 human observers showed that absorbed doses down to 40 mGy can be detected by the eye. Read by a portable densitometer, qualitative absorbed dose estimates down to 9 mGy can be achieved. The colour change is obtained instantaneously, giving first responders immediate information about the presence of beta-, gamma- and X-ray radiation.     

The contribution of parents’ driving behavior,family climate for road safety,and parent-targeted intervention to young male driving behavior

One of the prominent issues in contemporary research on young drivers deals with the mechanisms underlying parents’ influences on their offspring's driving behavior. The present study combines two sets of data: the first gathered from in-vehicle data recorders tracking the driving of parents and their teenage sons, and the second derived from self-report questionnaires completed by the young drivers. The aim was to evaluate the contribution of parents’ driving behavior, participation in a parent-targeted intervention, and the teen drivers’ perception of the family climate for road safety, to the driving behavior of young drivers during solo driving. The data was collected over the course of 12 months, beginning with the licensure of the teen driver, and examined a sample of 166 families who were randomly assigned to one of three intervention groups (receiving different forms of feedback) or a control group (with no feedback). Findings indicate that young male drivers’ risky driving events rate was positively associated with that of their parents. In addition, any type of intervention led to a lower rate of risky driving events among young drivers compared to the control group. Finally, a higher perception of parents as not committed to safety and lower perceived parental monitoring were related to a higher risky driving events rate among young drivers. The results highlight the need to consider a complex set of antecedents in parents’ attitudes and behavior, as well as the family's safety atmosphere, in order to better understand young drivers’ risky driving. The practical implications refer to the effective use of the family as a lever in the attempt to promote safety awareness among young drivers.     

Adsorption of zinc from aqueous solutions to bentonite

The adsorptive properties of natural and Na-enriched bentonite in zinc rich aqueous environment have been studied. The results show that adsorption behavior of both bentonites was strongly depending on the pH. At low pH values, the mechanisms that govern the adsorption behavior of bentonites are dissolution of crystal structure and competition of the metal ions with the H+. Between pH 4 and 7, the basic mechanism is an ion exchange process. The alkaline and alkaline earth metals located in the exchangeable sites of bentonites are replaced with Zn2+ cations present in the aqueous solution. At higher pH values (i.e. pH 8), formation of zinc hydroxyl species may result either participation to the adsorption or precipitation onto the bentonites. Therefore, a rapid increase in the equilibrium removal of zinc was obtained above pH 7. Increase in the initial metal ion concentration led to the increase in equilibrium adsorption to a certain degree; then, a plateau was obtained at higher concentrations. The rate of zinc removal depends also on the solid concentration of the suspension. Reducing the slurry concentration allows particles to get in the more dispersed form, resulting higher available sorption sites for zinc. As a result, the adsorption performance of Na-enriched bentonite is better than the natural bentonite in all physical and chemical changes. The data were fitted both Langmuir and Freundlich isotherms.     

Removal of chromium from aqueous solutions by treatment with fibrous carbon electrodes: column effects

The continuous removal of toxichexavalent chromium from contaminated solutions by means of a graphite felt based electrochemical column was studied. The process is based on anin situ generation of appropriate pH gradients which allows both rapid reduction to Cr³⁺ and its precipitation within the electrode bed. Conditions for the attainment of low (<25 p.p.b.) effluent concentrations as well as longitudinal concentration distribution of the precipitate and maximum loading capacities are presented. Treatment schemes involving two separate columns or a dual function column are also discussed.     

Inhalation by nebulization of albuterol-ipratropium combination (Dey combination) is superior to either agent alone in the treatment of chronic obstructive pulmonary disease. Dey Combination Solution Study Group

Combination bronchodilator therapy for chronic obstructive pulmonary disease (COPD) potentially can provide increased benefit over single-agent therapy. The objective of this double-blind, randomized, positive-control trial was to determine the effectiveness of an albuterol-ipratropium solution aerosol combination (Dey combination solution, Dey LP, Napa, Calif., USA) compared with solution aerosols of both component medications administered alone in patients with COPD. The trial consisted of a 6-week, 3-period crossover phase followed by a 6-week parallel phase during which patients self-administered study medications by inhalation from a nebulizer. A total of 863 patients were initially randomized to each of the six possible treatment sequences of the three study medications in the crossover phase and received each study medication in turn for a 2-week period. Patients continued to receive the same treatment administered during the last 2-week period of the crossover phase for an additional 6 weeks in the parallel phase. Assessment of 1-second forced expiratory volume (FEV1) curves before and after dosing on the last day of each 2-week period indicated that the combination was superior to either single agent in peak effect and area under the curve up to 8 h after dosing (FEV1-AUC0-8), in both phases of the trial. The use of Dey combination during the crossover phase resulted in 24% more improvement in peak FEV1 than was seen with albuterol alone (p < 0.001), and 37% more than was seen with ipratropium alone (p < 0.001). Similarly, when examining FEV1-AUC0-8, Dey combination resulted in 30% more improvement than was seen with albuterol alone (p < 0.001), and 32% more than was seen with ipratropium alone (p < 0.001). The combination affords a convenient dosing regimen and incorporates enhanced benefit without compromising the safety profile of either component agent.     

Graphite felt as an efficient porous electrode for impurity removal and recovery of metals

The properties of graphite felt as an efficient flow-through or flow-by electrode are demonstrated by the removal of traces of mercuric ions from aqueous electrolyte solutions. A simple and direct method is suggested for the determination of the concentration-distribution profile of the electro-deposit on the electrode. The data are compared to those obtained for electrodes used by other authors. It is concluded that mass transport and other properties are much better for the graphite felt than for the other electrodes, thus making it attractive for the use in electrochemical reactors.     

Three-part auctions versus self-commitment in day-ahead electricity markets

We examine the economic consequences of a bid-based security-constrained centralized unit commitment paradigm based on three-part offers, which is the prevalent day-ahead market-clearing mechanism in restructured electricity markets in the United States. We then compare this approach with an energy-only auction with self-commitment (such as in Australia) addressing efficiency and pricing as well as the tradeoff between coordination losses and incentives to bid truthfully.     

The Aral Sea and the Dead Sea: Disparate lakes with similar histories

In spite of significant differences in their sizes, depths, salinity and other properties, the Aral Sea and the Dead Sea share many features, as illustrated by a comparison of the histories of both water bodies. Fifteenth and early sixteenth century maps, based on the ‘Geography’ of Ptolemy, contain both lakes. The first successful limnological surveys of the lakes were made in the same year 1848, when Alexey Butakov explored the Aral Sea and William Lynch mapped the Dead Sea. Paintings and drawings by Taras Shevchenko (Aral Sea) and David Roberts (Dead Sea) document the landscapes around the lakes in the first half of the 19th century. The water balance of both lakes has been strongly negative in the past decades, leading to a decreased water surface area and volume for both lakes, their increased salinity and deterioration of their local infrastructures. Complex and expensive mitigation schemes have been proposed for both lakes, based on the import of large quantities of water from distant sources via canals or pipelines (i.e. Siberian rivers or Caspian Sea to supply water to the Aral Sea, Mediterranean Sea or Red Sea, to be connected with the Dead Sea). Less dramatic solutions to improve the local situations already have resulted in improved water quality in the Aral Sea, and partial restoration of its fisheries. In contrast, the Dead Sea remains much too saline to support higher forms of life. Nevertheless, a biblical prophecy predicts that even this most hypersaline of all lakes will eventually be teeming with fish of many kinds.