The moderating role of task characteristics in determining responses to a stressful work simulation

Two experimental studies were conducted to examine whether the stress‐buffering effects of behavioral control on work task responses varied as a function of procedural information. Study 1 manipulated low and high levels of task demands, behavioral control, and procedural information for 128 introductory psychology students completing an in‐basket activity. ANOVA procedures revealed a significant three‐way interaction among these variables in the prediction of subjective task performance and task satisfaction. It was found that procedural information buffered the negative effects of task demands on ratings of performance and satisfaction only under conditions of low behavioral control. This pattern of results suggests that procedural information may have a compensatory effect when the work environment is characterized by a combination of high task demands and low behavioral control. Study 2 (N=256) utilized simple and complex versions of the in‐basket activity to examine the extent to which the interactive relationship among task demands, behavioral control, and procedural information varied as a function of task complexity. There was further support for the stress‐buffering role of procedural information on work task responses under conditions of low behavioral control. This effect was, however, only present when the in‐basket activity was characterized by high task complexity, suggesting that the interactive relationship among these variables may depend on the type of tasks performed at work. Copyright © 1999 John Wiley & Sons, Ltd.     

Factor structure of the transformational leadership model in human service teams

The purpose of this study was to examine the factor structure of the transformational leadership model in human service teams. As the nature of this work environment mandates certain management‐by‐exception practices, patterns of correlations between perceptions of active and passive management‐by‐exception behaviors and transformational, transactional, and laissez‐faire leadership were of interest. 236 leaders and 620 subordinates from 54 mental health teams completed the Multifactor Leadership Questionnaire, form 8Y. Results suggest that active and passive management‐by‐exception factors are independent constructs. Copyright © 2003 John Wiley & Sons, Ltd.     

Partitioning of polychlorinated biphenyls in octanol/water, triolein/water, and membrane/water systems

The use of the octanol/water partition constant (Kow) as a surrogate parameter for lipid/water partitioning of persistent organic pollutants (POPs) was reassessed by comparing the measured Kow of 12 selected polychlorinated biphenyl congeners (PCBs) with partition constants in triolein/water (Ktw) and membrane/water (Kmw) systems. Kow and Ktw were measured by the slow-stirring method. Kmw was measured by an adaptation of the slow-stirring method using suspensions of phosphatidylcholine and phosphatidylserine liposomes. Partitioning of POPs to octanol, triolein, and liposomes is similar but not equal. The log-log correlation for Kow and Ktw is excellent (r2 = 0.982) and that for Kow and Kmw is somewhat weaker (r2 = 0.856). Ktw values are greater than Kow by a factor of 1.6. Kmw of some PCB congeners exceed both Kow and Ktw by an order of magnitude. The differences are attributed to different PCB activity coefficients in the different lipid phases. The results imply that Kow can be used as a reasonable conservative estimate of lipid/water partitioning. But the observed differences between Kow and Kmw also indicate that using Kow to predict accumulation of POPs, particularly highly hydrophobic ones, in the polar lipids of organisms will underestimate their concentrations at equilibrium.     

Modifications to an H2S Tape Sampler for Increasing Sensitivity and Accuracy in H2S Sampling

The tape samplers using lead acetate impregnated paper tapes for continuous hydrogen sulfide sampling are subject to a number of errors which can throw considerable doubt on the accuracy of H₂S concentrations being measured. Some of the errors have been minimized with a change in the humidification system and a reduction of the lamp intensity in the optical system.     

UV-VIS spectroscopy of 2,4,6-trinitrotoluene-hydroxide reaction

Contamination of groundwater, surface water and soil by explosives has occurred at military sites throughout the world as a result of manufacture of explosive compounds, assembly of munitions, and deployment of explosives containing devices. Due to the adverse effects of explosives on humans and other natural receptors, a low cost means of decontaminating these areas of contamination is needed. Base-induced transformation of explosives has shown promise as a rapid, low cost, and minimally resource-intensive technology for detoxifying explosives in soil and water. In order to understand the reaction mechanism, a reaction mixture of 2:1:1 (water:2,4,6-trinitrotoluene (TNT):1 N KOH) was analyzed by UV/VIS spectrometry from 190 to 1,100 nm. Time course measurements were conducted at 25, 20, 15, and 12 degrees C. A factor analysis program was used to analyze the spectral data. Principal component analysis indicated that six principal components explained the spectra to within experimental error, with four factors explaining the majority of the variance. Test spectral vectors for four components were developed, including TNT, two intermediates, and the final product, and were tested against the abstract vectors. Two possible reaction mechanisms were suggested and tested to explain the spectral data.     

Electrolytic debromination of PBDEs in DE-83 technical decabromodiphenyl ether

Electrochemical debromination of the commercial decabromodiphenyl ether flame retardant DE-83 in partly aqueous tetrahydrofuran (THF) solution gave lower brominated congeners by sequential loss of bromine atoms. Hydrodebromination was most facile for the most heavily brominated congeners. It involves initial electron transfer and proton transfer from water, rather than hydrogen atom abstraction from THF, as shown by experiments with deuterated water. The product distribution from electrolysis involves preferential loss of bromine meta- and para- to the ether linkage, comparable with the products of metabolism of BDE-209 in various organisms. Significantly, the environmentally relevant congeners BDE-47, BDE-99, and BDE-154 were not major products of debromination of BDE-209 by the electron transfer mechanism.     

Structure characterization and thermal stabilities of the isomers of the brominated flame retardant 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane

1,2-Dibromo-4-(1,2-dibromoethyl)cyclohexane (TBECH) is used primarily as an additive flame retardant. 1H NMR spectroscopy and an X-ray structure determination have revealed that a technical mixture consists largely of two (of the four possible) diastereomers, rac-(1R,2R)-1,2-dibromo-(4S)-4-((1S)-1,2-dibromoethyl)cyclohexane (alpha-TBECH) and rac-(1R,2R)-1,2-dibromo-(4S)-4-((1R)-1,2-dibromoethyl)cyclohexane (beta-TBECH), in a mole ratio of approximately 1:1. The two other possible isomers, gamma- and delta-TBECH, were not detected in a technical mixture. The TBECH isomers are thermally sensitive and can easily interconvert at temperatures of 125 degrees C. A thermal equilibrium mixture of alpha-, beta-, gamma- and delta-TBECH consists of approximately 33%, 33%, 17% and 17% of these isomers, respectively. Separation of all four TBECH diastereomers, with minimal thermal interconversion of the isomers, was achieved by careful selection of GC-capillary column length and injector temperature. Although technical TBECH does not contain the gamma- and delta-isomers, they may still be relevant environmental contaminants since manufacturing processes utilize thermal processes which may induce their formation.