Relationships among five forms of commitment: an empirical assessment

This paper examined whether Morrow's (1993) model of five universal forms of work commitment (affective organizational commitment, continuance organizational commitment, career commitment, job involvement and work ethic endorsement) has empirical support. The paper explored the discriminant validity among the five scales of these commitment forms. It also tested Morrow's model regarding the interrelationships among them in comparison with an alternative conceptualization proposed by Randall and Cote (1991). Two hundred and thirty‐eight nursing staff from two hospitals in western Canada were surveyed. Results of confirmatory factor analysis (LISREL VIII) and correlation analysis showed an acceptable discriminant validity among the five commitment foci. The results of path analysis (LISREL VIII) showed a poor fit with the data of Morrow's model and a better fit with the alternative model of Randall and Cote. Revised models based on the modification indices from both models were tested, and supported the Randall and Cote approach. The paper concludes with implications regarding the continuing assessment of Morrow's conceptualization to establish an acceptable definition and measurement of universal forms of work commitment. Copyright © 1999 John Wiley & Sons, Ltd.     

Preparedness for anthrax attack: the effect of knowledge on the willingness to treat patients

Little is known about the factors that may impact on the willingness of physicians and nurses to treat patients during a bioterrorism attack. This survey was conducted among 76 randomly selected nurses and physicians in the emergency rooms of three public hospitals in order to analyse the relationship between knowledge, profession and the willingness to treat anthrax. The study finds that the willingness of physicians and nurses to come to work is 50% greater among the group with the highest knowledge about anthrax (P < 0.0001). Within that group, the willingness to treat patients suspected of being infected with anthrax was 37% greater (P < 0.0001) and the willingness to treat patients diagnosed with anthrax was 28% greater (P = 0.004) than in the other groups. These results imply that enhancement of knowledge among health care workers may improve their willingness to come to work and treat patients infected with anthrax during a bioterrorism attack.     

Evaluating Ecological Condition Using Soil Biogeochemical Parameters and Near Infrared Reflectance Spectra

Rapid, repeatable assessment of ecological condition is critical for quantitative ecosystem monitoring. Soils provide a sensitive, integrative indicator for which sampling and analysis techniques are well defined. We evaluated soil properties as indicators of ecological condition (subjectively classified into minimally/moderately/severely degraded based on vegetative, hydrologic and edaphic cues) at 526 sites within Ft. Benning military installation (Georgia, USA). For each sample, we measured 17 biogeochemical parameters, and collected high-resolution diffuse reflectance spectra using visible/near infrared reflectance spectroscopy (VNIRS). VNIR spectra have been related to numerous soil attributes — we examine them here for diagnosing integrated response (i.e., ecological condition). We used ordinal logistic regression (OLR) and classification trees (CT) to discriminate between condition categories using both sets of predictors (biogeochemistry and spectra). Sixteen biogeochemical parameters were significantly different across condition categories; however, multivariate models greatly improved discrimination ([calibration, validation] accuracy of [69%, 66%] and [96%, 73%] for OLT and CT models, respectively). Important predictors included total C, total P, and Mehlich K/Ca/Mg. VNIR spectra further improved discrimination ([calibration, validation] accuracy of [74%, 70%] and [96%, 75%] for OLR and CT models, respectively). While spectra were comparably effective at discriminating minimally degraded sites, they were significantly more effective at discriminating severely degraded sites. Error rates across confounding factors suggest that watershed of origin and landscape position were the only important confounders, likely due to imbalanced sampling. We conclude that multivariate diagnosis improves accuracy, and that VNIR spectroscopy, which yields substantial cost and logistical improvements over conventional analyses, provides an effective tool for rapid condition diagnosis.     

Zero valent iron remediation of a mixed brominated ethene contaminated groundwater

The suitability of a granulated zero valent iron (ZVI) permeable reactive barrier (PRB) remediation strategy was investigated for tribromoethene (TriBE), cis-1,2-dibromoethene (c-DBE), trans-1,2-dibromoethene (t-DBE) and vinyl bromide (VB), via batch and large-scale column experiments that were subsequently analysed by reactive transport modelling.The brominated ethenes in both batch and large-scale column experiments showed rapid (compared to controls and natural attenuation) degradation in the presence of ZVI. In the large-scale column experiment, degradation half-lives were 0.35 days for TriBE, 0.50 days for c-DBE, 0.31 days for t-DBE and 0.40 days for VB, under site groundwater flow conditions, resulting in removal of brominated ethenes within the first 0.2 m of a 1.0 m thick ZVI layer, indicating that a PRB groundwater remediation strategy using ZVI could be used successfully.In the model simulations of the ZVI induced brominated ethene degradation, assuming a dominant reductive β-elimination pathway via bromoacetylene and acetylene production, simulated organic compound concentrations corresponded well with both batch and large-scale column experimental data. Changes of inorganic reactants were also well captured by the simulations. The similar ZVI induced degradation pathway of TriBE and TCE suggests that outcomes from research on ZVI induced TCE remediation could also be applied to TriBE remediation.     

Pollution influences on atmospheric composition and chemistry at high northern latitudes: Boreal and California forest fire emissions

We analyze detailed atmospheric gas/aerosol composition data acquired during the 2008 NASA ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) airborne campaign performed at high northern latitudes in spring (ARCTAS-A) and summer (ARCTAS-B) and in California in summer (ARCTAS-CARB). Biomass burning influences were widespread throughout the ARCTAS campaign. MODIS data from 2000 to 2009 indicated that 2008 had the second largest fire counts over Siberia and a more normal Canadian boreal forest fire season. Near surface arctic air in spring contained strong anthropogenic signatures indicated by high sulfate. In both spring and summer most of the pollution plumes transported to the Arctic region were from Europe and Asia and were present in the mid to upper troposphere and contained a mix of forest fire and urban influences. The gas/aerosol composition of the high latitude troposphere was strongly perturbed at all altitudes in both spring and summer. The reactive nitrogen budget was balanced with PAN as the dominant component. Mean ozone concentrations in the high latitude troposphere were only minimally perturbed (<5 ppb), although many individual pollution plumes sampled in the mid to upper troposphere, and mixed with urban influences, contained elevated ozone (ΔO₃/ΔCO = 0.11 ± 0.09 v/v). Emission and optical characteristics of boreal and California wild fires were quantified and found to be broadly comparable. Greenhouse gas emission estimates derived from ARCTAS-CARB data for the South Coast Air Basin of California show good agreement with state inventories for CO₂ and N₂O but indicate substantially larger emissions of CH₄. Simulations by multiple models of transport and chemistry were found to be broadly consistent with observations with a tendency towards under prediction at high latitudes.     

Understanding adaptive capacity and capacity to innovate in social–ecological systems: Applying a gender lens

Development policy increasingly focuses on building capacities to respond to change (adaptation), and to drive change (innovation). Few studies, however, focus specifically on the social and gender differentiation of capacities to adapt and innovate. We address this gap using a qualitative study in three communities in Solomon Islands; a developing country, where rural livelihoods and well-being are tightly tied to agriculture and fisheries. We find the five dimensions of capacity to adapt and to innovate (i.e. assets, flexibility, learning, social organisation, agency) to be mutually dependant. For example, limits to education, physical mobility and agency meant that women and youth, particularly, felt it was difficult to establish relations with external agencies to access technical support or new information important for innovating or adapting. Willingness to bear risk and to challenge social norms hindered both women’s and men’s capacity to innovate, albeit to differing degrees. Our findings are of value to those aspiring for equitable improvements to well-being within dynamic and diverse social–ecological systems.     

Epidemiological Bases for Possible Air Quality Criteria for Carbon Monoxide

Exposures to adequate environmental levels of CO will increase COHb concentrations in human subjects. The amount of this increase is reasonably predictable, and must be considered in relation to exposure to CO in inhaled cigarette smoke as well as to occupational and domestic exposures. The increase in body COHb will result in some degree of impairment of tissue oxygenation.

Methods for estimating COHb levels in large populations are relatively simple. The assumption that an exposure to 30 ppm CO for eight hours will produce on the average, an increase in COHb of 5%, has been substantiated by available data.

Exposure for five hours to between 10 and 12 ppm of CO has been shown to increase the COHb levels in nonsmokers by at least 0.5%. Such an increase adds appreciably to the body burden of COHb in those who do not already have such a body burden from cigarette smoking. Longer exposures could have produced a somewhat greater increase.

Apart from increases in COHb, three possible effects have been a source of major consideration in epidemiologic studies. The first is the production of some persistent toxic reaction. This possibility has been examined with respect to occupational exposure, and the evidence for the occurrence of such a condition is insufficient.

The possible contribution of ambient community CO exposure to the mortality of persons hospitalized with myocardial infarction has been investigated. The evidence suggests that daily average CO values in excess of about 10 ppm may be associated with an increase in mortality in hospitalized patients with myocardial infarction. Substantiation of this impression will require a study of the prognosis of myocardial infarction patients in relationship to COHb levels measured at admission to the hospital.

Finally, in two studies, persons driving motor vehicles which were involved in accidents had higher COHb levels than "control" populations. Controls were not ideal, however. Possible mechanisms by which CO might affect the ability to drive a motor vehicle is suggested in the available data on CO effects upon visual sensitivity, psychological test performance and accurate estimation of time intervals. As little as 2 percent COHb can produce these effects in laboratory studies, and the available epidemiologic information confirms that such an increase in COHb levels among drivers might influence the frequency of accidents.

Specific areas where research is indicated to clarify uncertainties relating to health effects of CO are: 1. The increment in COHb which can be produced by exposures to an average of 20 ppm CO for an eight hour period and the increment which can be produced by 15 ppm for such a period and by 10 ppm for up to twenty-four hours.

2. The relationship of ambient CO levels and of COHb levels to the survival of hospitalized patients with myocardial infarction.

3. The prognostic significance with respect to cardiovascular conditions of elevated levels of COHb.

4. The relationship, if any, between ambient CO and COHb levels and the occurrence of motor vehicle accidents when weather and driving conditions, cigarette smoking, alcohol and drug use, and other factors are adjusted and controlled.

     

Mercury species measured atop the Moody Tower TRAMP site,Houston, Texas

Atmospheric mercury speciation was monitored within Houston, Texas, USA, August 6–October 14, 2006 as part of the TexAQS Radical and Aerosol Measurement Program (TRAMP). On average, all mercury levels were significantly elevated compared to a rural Gulf of Mexico coastal site. Concentrations varied from very clean to very dirty. Multi-day periods of stagnant or low-wind conditions brought elevated concentrations of all mercury species, whereas multi-day periods of strong winds, particularly southerly winds off the Gulf of Mexico, brought very low values of mercury species. Over the entire mercury measurement period, the daily averages of mercury species showed distinct and consistent relationships with the average planetary boundary layer dynamics, with gaseous elemental and particulate-bound mercury near-surface concentrations enhanced by a shallow nocturnal boundary layer, and reactive gaseous mercury concentration enhanced by midday convective boundary layer air entrainment transporting air aloft to the surface. Mercury concentrations were not significantly correlated with known products of combustion, likely indicating non-combustion mercury sources from the Houston area petrochemical complexes. On the morning of August 31, 2006 an observed emission event at a refinery complex on the Houston Ship Channel resulted in extremely high concentrations of aerosol mass and particulate-bound mercury at the TRAMP measurement site 20 km downwind.