Active learning climate and employee errors: The moderating effects of personality traits

This study developed and tested a cross‐level model of the relationship between two components of active learning climate—enactive exploration and guided learning—and employee errors, and the moderating roles of the individual's traits of openness to experience and conscientiousness. The study examined the medical errors made by 142 resident physicians in 22 hospital departments. Results demonstrated significant interactions between climate and traits: when an individual had a low level of the trait of openness to experience, there was a curvilinear relationship between enactive exploration climate and number of errors. With a high level of openness to experience, the enactive exploration climate was positively associated with the number of errors up to a certain point. In addition, when an individual had a low level of conscientiousness, there was a negative association between guided learning climate and number of errors; with a high level of conscientiousness, there was a positive association between guided learning climate and number of errors. Thus, individual performance was better when the climate complemented the individual's lack of a trait. When the level of the individual's trait was high, the climate intensified the already pronounced trait up to an extent that impaired the individual's performance. Copyright © 2015 John Wiley & Sons, Ltd.     

Shifts in grassland invasibility: effects of soil resources, disturbance, composition, and invader size

There is an emerging recognition that invasibility is not an intrinsic community trait, but is a condition that fluctuates from interactions between environmental forces and residential characters. Elucidating the spatiotemporal complexities of invasion requires inclusion of multiple, ecologically variable factors within communities of differing structure. Water and nutrient amendments, disturbance, and local composition affect grassland invasibility but no study has simultaneously integrated these, despite evidence that they frequently interact. Using a split-plot factorial design, we tested the effects of these factors on the invasibility of C3 pasture communities by smooth pigweed Amaranthus hybridus L., a problematic C4 forb. We sowed seeds and transplanted 3-week old seedlings of A. hybridus into plots containing monocultures and mixtures of varying composition, subjected plots to water, soil disturbance, and synthetic bovine urine (SBU) treatments, and measured A. hybridus emergence, recruitment, and growth rate. Following SBU addition, transplanted seedling growth increased in all plots but differed among legume and nonlegume monocultures and mixtures of these plant types. However, SBU decreased the number and recruitment rate of emerged seedlings because high residential growth reduced light availability. Nutrient pulses can therefore have strong but opposing effects on invasibility, depending on when they coincide with particular life history stages of an invader. Indeed, in SBU-treated plots, small differences in height of transplanted seedlings early on produced large differences in their final biomass. All facilitative effects of small-scale disturbance on invasion success diminished when productivity-promoting factors were present, suggesting that disturbance patch size is important. Precipitation-induced invasion resistance of C3 pastures by a C4 invader was partly supported. In grazed grasslands, these biotic and environmental factors vary across scales and interact in complex ways to affect invasibility, thus a dynamic patch mosaic of differential invasion resistance likely occurs in single fields. We propose that disturbance patch size, grazing intensity, soil resource availability, and resident composition are inextricably linked to grassland invasions and comment on the utility of community attributes as reliable predictors of invasibility. Lastly, we suggest temporal as well as spatial coincidences of multiple invasion facilitators dictate the window of opportunity for invasion.     

Social dimensions of mining: Research,policy and practice challenges for the minerals industry in Australia

The social dimensions of the mining industry are increasingly acknowledged as critical to business success, yet remain the least understood aspect of the business concept of sustainable development—the ‘triple bottom line’ of economy, environment and society.     

Monopoly exploitation of an exhaustible resource

The popular notion that a monopolist will exhaust a nonrenewable natural resource at a slower than socially optimal rate is examined. Contrary to the prevailing belief, instances do exist for which the monopolist uses the resource faster than the social maximizer. This is demonstrated first by finding conditions for which the expected result—a monopoly rate which is slower than optimal-will always hold, and second, by showing that for situations where these conditions are violated the result may be reversed.     

PRECIPITATION MEASUREMENT BIASES IN THE UNITED STATES1

ABSTRACT: Gage-induced biases in monthly precipitation are estimated and removed at 1818 stations across the continental United States from 1950 through 1987. Deleterious effects of the wind and wetting losses on the interior walls of the gage were considered. These “corrected” estimates were obtained using site-specific information including wind speed, shelter-height air temperature, gage height, and sheltering. Wind speed and air temperature were interpolated at stations for which these data were not available using a spherically-based, nearest neighbor interpolation procedure. Results indicate that, as expected, biases are greater in the winter than the summer owing to the increased problems (particularly wind-induced) of measuring snowfall. In summer, percent errors range between 4 and 6 percent over nearly three-quarters of the United States with slightly larger errors over the Rocky Mountains. By contrast, winter biases are highly correlated with snowfall totals and percentage errors increase poleward, mimicking patterns of snowfall frequency. Since these biases are not trivial, they must be accounted for in order to obtain accurate and reliable time-series. If these biases are not properly addressed, serious errors can be introduced into climate change, hydrologic modeling, and environmental impact research.     

Mass loading of nickel and uranium on plant surfaces: application of laser ablation-ICP-MS

Transport of contaminated sediments from a former radiological settling pond results in the deposition of U and Ni in the Lower Tims Branch (LTB)(Aiken, SC, USA). Uranium is unavailable for plant uptake, but elevated U and Ni concentrations associated with foliage of understory plants suggested mass loading. Mass loading of contaminated soil on Andropogon elliottii Chapman (Poaceae) was investigated using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The technique allows for rapid quantitative elemental depth profiling. Fresh washed and unwashed leaves (n= 5) from the contaminated area were compared with those from an uncontaminated area, analysing Ni and U at ten randomly chosen points on each leaf. Nickel and U concentrations differed significantly between washed and unwashed leaves from LTB. Particles on unwashed leaves measured up to 300 [micro sign]m in diameter, and were enriched with U. Uranium was detected on the surface of the leaf, whereas Ni was detected within leaf tissues. In unwashed LTB leaves, Ni and U concentrations did not significantly differ in areas with and without visible particles, suggesting that there were much smaller particles, indistinguishable at [times]100 magnification, which contributed to the overall metal burden. Washing removed the majority of the Ni and U on the surface, but residual U and Ni was detected. Irregularities in the leaf surface, such as scars from herbivory contained elevated U concentrations despite a washing step, presumably from trapping soil particles. Laser ablation ICP-MS revealed that mass loading makes a significant contribution to the contaminant burden of understory plants at LTB.     

A life-cycle comparison of several auxiliary blowing agents used for the manufacture of rigid polyurethane foam

In a commitment to zero ozone depletion, the United Nations and the U.S. Environmental Protection Agency (EPA) have called for the phase-out of the manufacture and import of hydrochlorofluorocarbons (HCFCs), used as auxiliary blowing agents (ABAs) in the manufacture of polyurethane foams. As a result, more environmentally benign alternative ABAs are being sought by the foam-blowing industry. This study examined the life cycle of HCFC-22, hydrofluorocarbon-134a (HFC-134a), and cyclopentane, which are currently used or considered as potential alternative ABAs in the manufacture of rigid polyurethane foams that serve as insulation in a model North American refrigerator. The raw material extraction/refining, manufacturing, use, and disposal stages of the life cycle of each ABA were considered, and their resulting relative impacts on ozone depletion and global warming were compared. The manufacturing, use, and disposal stages were determined to affect ozone depletion and global warming to the largest extent, emphasizing the need for a greater focus on pollution prevention opportunities in these stages. The HFC-134a life cycle yields no impact on ozone depletion and a significantly decreased global warming impact compared with its predecessor, HCFC-22, and a tradeoff of slightly higher global warming impact and fewer added safety concerns compared with its more flammable counterpart, cyclopentane.     

INTERACTIONS BETWEEN GROUND WATER AND SURFACE WATER IN THE SUWANNEE RIVER BASIN,FLORIDA1

ABSTRACT: Ground water and surface water constitute a single dynamic system in most parts of the Suwannee River basin due to the presence of karst features that facilitate the interaction between the surface and subsurface. Low radon-222 concentrations (below background levels) and enriched amounts of oxygen-18 and deuterium in ground water indicate mixing with surface water in parts of the basin. Comparison of surface water and regional ground water flow patterns indicate that boundaries for ground water basins typically do not coincide with surface water drainage subbasins. There are several areas in the basin where ground water flow that originates outside of the Suwannee River basin crosses surface water basin boundaries during both low-flow and high-flow conditions. In a study area adjacent to the Suwannee River that consists predominantly of agricultural land use, 18 wells tapping the Upper Floridan aquifer and 7 springs were sampled three times during 1990 through 1994 for major dissolved inorganic constituents, trace elements, and nutrients. During a period of above normal rainfall that resulted in high river stage and high ground water levels in 1991, the combination of increased amounts of dissolved organic carbon and decreased levels of dissolved oxygen in ground water created conditions favorable for the natural reduction of nitrate by denitrification reactions in the aquifer. As a result, less nitrate was discharged by ground water to the Suwannee River.