Calculation of composition,stability and free energy of formation of complex argentothiocyanate ion from solubility data

The Science of Nature -     

Modeling the Impacts of Two Bark Beetle Species Under a Warming Climate in the Southwestern USA: Ecological and Economic Consequences

Predicted climate warming is expected to have profound effects on bark beetle population dynamics in the southwestern United States. Temperature-mediated effects may include increases in developmental rates, generations per year, and changes in habitat suitability. As a result, the impacts of Dendroctonus frontalis and Dendroctonus mexicanus on forest resources are likely subject to amplification. To assess the implications of such change, we evaluated the generations per year of these species under three climate scenarios using a degree-day development model. We also assessed economic impacts of increased beetle outbreaks in terms of the costs of application of preventative silvicultural treatments and potential economic revenues forgone. Across the southwestern USA, the potential number of beetle generations per year ranged from 1–3+ under historical climate, an increase of 2–4+ under the minimal warming scenario and 3–5+ under the greatest warming scenario. Economic benefits of applying basal area reduction treatments to reduce forest susceptibility to beetle outbreaks ranged from 7.75/ha (NM) to7.75/ha (NM) to 95.69/ha (AZ) under historical conditions, and 47.96/ha (NM) to47.96/ha (NM) to 174.58/ha (AZ) under simulated severe drought conditions. Basal area reduction treatments that reduce forest susceptibility to beetle outbreak result in higher net present values than no action scenarios. Coupled with other deleterious consequences associated with beetle outbreaks, such as increased wildfires, the results suggest that forest thinning treatments play a useful role in a period of climate warming.     

Sorption kinetics and leachability of heavy metal from the contaminated soil amended with immobilizing agent (humus soil and hydroxyapatite)

Release of heavy metals onto the soil as a result of agricultural and industrial activities may pose a serious threat to the environment. This study investigated the kinetics of sorption of heavy metals on the non-humus soil amended with (1:3) humus soil and 1% hydroxyapatite used for in situ immobilization and leachability of heavy metals from these soils. For this, a batch equilibrium experiment was performed to evaluate metal sorption in the presence of 0.05 M KNO(3) background electrolyte solutions. The Langmuir isotherms applied for sorption studies showed that the amount of metal sorbed on the amended soil decreased in the order of Pb(2+)>Zn(2+)>Cd(2+). The data suggested the possibility of immobilization of Pb due to sorption process and immobilization of Zn and Cd by other processes like co-precipitation and ion exchange. The sorption kinetics data showed the pseudo-second-order reaction kinetics rather than pseudo-first-order kinetics. Leachability study was performed at various pHs (ranging from 3 to 10). Leachability rate was slowest for the Pb(2+) followed by Zn(2+) and Cd(2+). Out of the metal adsorbed on the soil only 6.1-21.6% of Pb, 7.3-39% of Zn and 9.3-44.3% of Cd leached out from the amended soil.     

Workers' perceptions of workplace safety and job satisfaction.

A lot of attention has been focused on workers' perceptions of workplace safety but relatively little or no research has been done on the impact of job satisfaction on safety climate. This study investigated this relationship. It also examined the relationships between job satisfaction and workers' compliance with safety management policies and accident frequency. A positive association was found between job satisfaction and safety climate. Workers who expressed more satisfaction at their posts had positive perceptions of safety climate. Correspondingly, they were more committed to safety management policies and consequently registered a lower rate of accident involvement. The results were thus consistent with the notion that workers' positive perceptions of organisational climate influence their perceptions of safety at the workplace. The findings, which have implications in the work environment, are discussed.     

Valuing the benefits of the urban forest: a spatial hedonic approach

This paper measures the benefits of the urban forest by examining its effect on housing prices. A Geographic Information System is used to develop a measure of the urban forest, the Normalised Difference Vegetation Index, from satellite imagery and to construct other variables from a variety of sources. Spatial hedonic housing price models for the Indianapolis/Marion County area are estimated. The models indicate that greener vegetation around a property has a positive, significant effect on housing price, holding everything else constant. This effect is dominated by measures at the neighborhood level. These findings indicate that property owners value the urban forest, at least in part, by the premium they pay to live in neighborhoods with greener, denser vegetation. These findings also indicate that public action to maintain and enhance the urban forest may be warranted. Planners and urban foresters can use these findings to inform public and policy debates over urban forestry programs and proposals.     

Workplace safety perceptions and perceived organizational support: do supportive perceptions influence safety perceptions?

The current study investigated the relationship between organizational safety climate and perceived organizational support. Additionally, it examined the relationship with job satisfaction, worker compliance with safety management policies, and accident frequency. Safety climate and supportive perceptions were assessed with Hayes, Perander, Smecko, et al. 's (1998) and Eisenberger, Fasolo and LaMastro's (1990) scales respectively. Confirmatory factors analysis confirmed the 5-factor structure of Hayes et al. 's WSS scale. Regression analysis and t-tests indicated that workers with positive perspectives regarding supportive perceptions similarly expressed positive perceptions concerning workplace safety. Furthermore, they expressed greater job satisfaction, were more compliant with safety management policies, and registered lower accident rates. The perceived level of support in an organization is apparently closely associated with workplace safety perception and other organizational and social factors which are important for safety. The results are discussed in light of escalating interest in how organizational factors affect employee safety and supportive perceptions.     

Review, development and monitoring of national sustainable development strategies in Ghana

Agenda 21 requires that countries adopt ‘national sustainable development strategies’ (NSDS), and this has been emphasized in several international commitments. Ghana has contributed to the methodology for peer review of such national strategies, as well as to guidelines designed by OECD and the United Nations for the NSDS process. Ghana has also adopted mechanisms to manage its own development planning in a sustainable manner. This article highlights various types of frameworks for sustainable development currently operating in Ghana, and considers to what extent they conform to NSDS principles. The article concludes that Ghana has made progress in several ways, but faces some of the same challenges as other countries in adhering to sustainability principles. The article offers recommendations as to how Ghana can achieve sustainable development. The article is an independent assessment by the author, who has also formulated most of the recommendations, except where otherwise indicated.     

Organic compound emissions from a landfarm used for oil and gas solid waste disposal

Solid or sludgy hydrocarbon waste is a by-product of oil and gas exploration and production. One commonly used method of disposing of this waste is landfarming. Landfarming involves spreading hydrocarbon waste on soils, tilling it into the soil, and allowing it to biodegrade. We used a dynamic flux chamber to measure fluxes of methane, a suite of 54 nonmethane hydrocarbons, and light alcohols from an active and a remediated landfarm in eastern Utah. Fluxes from the remediated landfarm were not different from a polytetrafluoroethylene (PTFE) sheet or from undisturbed soils in the region. Fluxes of methane, total nonmethane hydrocarbons, and alcohols from the landfarm in active use were 1.41 (0.37, 4.19) (mean and 95% confidence limits), 197.90 (114.72, 370.46), and 4.17 (0.03, 15.89) mg m^?2 hr^?1, respectively. Hydrocarbon fluxes were dominated by alkanes, especially those with six or more carbons. A 2-ha landfarm with fluxes of the magnitude we observed in this study would emit 95.3 (54.3, 179.7) kg day^?1 of total hydrocarbons, including 11.2 (4.3, 33.9) kg day^?1 of BTEX (benzene, toluene, ethylbenzene, and xylenes).

Implications: Solid and sludgy hydrocarbon waste from the oil and gas industry is often disposed of by landfarming, in which wastes are tilled into soil and allowed to decompose. We show that a land farm in Utah emitted a variety of organic compounds into the atmosphere, including hazardous air pollutants and compounds that form ozone. We calculate that a 2-ha landfarm facility would emit 95.0 ± 66.0 kg day^?1 of total hydrocarbons, including 11.1 ± 1.5 kg day^?1 of BTEX (benzene, toluene, ethylbenzene, and xylenes).