Objective job conditions,social support and perceived stress among blue collar workers

The hypothesis that perceived supportive relations mediate the association between extra-individual (objective) job conditions and perceptions of occupational stress is tested in a population of blue collar workers. Responses to a mailed questionnaire (N = 1830) include measures of social support from four sources (supervisor, coworkers, spouse, friends/relatives) and measures of perceived stress (five job pressures and four need deprivations). In addition, company records and expert ratings by company, union and study personnel provide measures of objective job conditions which are commensurate with the subjective reports. Associations between objective job conditions and perceived stress are significant but modest in size. Controls for age, education, exposure to noxious agents and physical effort on the job do not alter associations between objective conditions and perceived stress. For five of the nine indicators of perceived stress, social support and objective conditions interact in determining perceptions. This is interpreted as a buffering effect in which social support provides a context that significantly alters perceptions of job conditions. The effect of supervisor support is especially important in regard to buffering. It is suggested that research on the quality of work should be especially aware of the conditional nature of the relationship between objective job conditions and perceptions.     

MEASURING IMPACTS OF WATER RESOURCE DEVELOPMENTS ON THE HUMAN ENVIRONMENT1

The parameters and the measurement procedures described in this paper are seen as being part of the first stage in development of the human environment assessment process. Additional parameters need to be identified, and methods of measuring impacts reflected by the parameters must be developed and refined. Considerations of the human environment and those elements of the natural environment that are of importance to people must be included as an integral part of the environmental impact assessment process. Therefore, there is a need for continuing to identify parameters of the human environment and to develop methods of measuring impacts so that these considerations will become a well-integrated part of the environmental impact assessment process.     

A Study of Primary Sulfate Emissions From a Coal-Fired Boiler with FGD

A study was carried out to investigate the emissions of SO₂ and primary sulfate materials (H₂SO₄ and inorganic particulate matter) from a boiler burning fossil fuel and using a wet-limestone scrubber for SO₂ removal. Experiments were designed to assess the scrubbing efficiency for SO₂ and sulfate, as well as the potential for scrubber liquor reentrainment. The boiler studied was an 820 MW cyclone-fired unit equipped with a wet, limestone scrubber, consisting of eight two-stage venturi-absorber modules designed to treat a flue gas flow rate of 2,760,000 acfm. The boiler fuel was a low-grade sub-bituminous coal with ash and sulfur contents of 25 and 5%, respectively. Multiple-sampling methods were employed concurrently on the inlet and outlet of a candidate absorber module to measure SO₂, total water-soluble sulfate, and free H₂SO₄. Samples were collected during three field experiments from September 1977 through April 1978. The average SO₂ scrubbing efficiency was 76% and was observed to decrease over the 5 day operation/maintenance cycle of the module. The total water-soluble sulfate input to the scrubber amounted to approximately 1% of the total sulfur oxides and was composed of a 5:1 ratio of H₂SO₄ to particulate sulfate. The total sulfate scrubbing efficiency, averaging about 29%, was invariant with respect to SO₂ removal. The sulfate emissions measured in the scrubber exit gas consisted of about 85 % H₂SO₄ as a fine aerosol. Mass emissions of acid and particulate sulfate were calculated as 1730 Ib/hr and 305 Ib/hr, respectively.     

Interactions among sea otters, sea stars, and suspension-feeding invertebrates in the western Aleutian archipelago

The structuring and organizing effects of apex predators on ecosystems are becoming increasingly well documented. The enhancement of kelp forests via sea otter predation on herbivorous sea urchins is among the earliest and best known examples. This study provides evidence for direct and indirect trophic interactions among sea otters, predatory sea stars, and filter-feeding mussels (Mytilus trossulus) and barnacles (Semibalanus cariosis). In western Massacre Bay at Attu Island (173°E, 53°N), subtidal transects showed sea star body size and biomass density declined markedly between 1983 and 1994 as sea otters reinhabited this area. Mussels and barnacles translocated from the rocky intertidal zone to shallow subtidal habitats to assess loss rates from sea star predation showed lower mortality rates after the arrival of sea otters. Prey mortality rates in subtidal caged controls were consistently low and similar to those of intertidal controls in both years. These findings elucidate a trophic pathway by which sea otters can influence ecosystems separate from the well-known sea otter/sea urchin/macroalgae cascade.     

Fetal magnetocardiography using optically pumped magnetometers: a more adaptable and less expensive alternative?

Fetal magnetocardiography provides the requisite precision for diagnostic measurement of electrophysiological events in the fetal heart. Despite its significant benefits, this technique with current cryogenic based sensors has been limited to few centers, due to high cost of maintenance. In this study, we show that a less expensive non-cryogenic alternative, optically pumped magnetometers, can provide similar electrophysiological and quantitative characteristics when subjected to direct comparison with the current technology. Further research can potentially increase its clinical use for fetal magnetocardiography. © 2016 John Wiley & Sons, Ltd.