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41.
Establishing the relationship between level of safety climate and safety performance is a current challenge. This work examines the relationship between level of safety climate and orientation toward safety in the decision making process and choice. Alternatively, this work seeks to answer the question of whether level of safety climate can predict safety-oriented decision making. A generalized safety climate questionnaire and a decision making simulation are utilized to examine this relationship. The results indicate that level of safety climate is not a significant predictor of the decision process; however, it was found to be a significant predictor of the selection of safer choices.  相似文献   
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43.
Feral swine were targeted for control at Avon Park Air Force Range in south-central Florida to avert damage to sensitive wetland habitats on the 40,000-ha base. We conducted a 5-year study to assess impacts from control to this population that had been recreationally hunted for many years. Control was initiated in early 2009. The feral swine population was monitored from 2008 to 2012 using a passive tracking index (PTI) during the dry and wet seasons and using recreational hunter take rates from the dry season. All three indices showed substantial feral swine declines after implementing control, with indices leveling for the final two study years. Military missions and recreational hunting seasons impacted temporal and spatial consistency of control application, thereby limiting further impacts of control efforts on the feral swine population. The PTI was also able to monitor coyotes, another invasive species on the base, and detect Florida black bear and Florida panther, species of particular concern.  相似文献   
44.
The most advantageous approach to pathogen destruction in a urine-diversion toilet vault is to maximize the effects of various environmental factors (i.e., pH, temperature, moisture content, type of bulking agent, and storage time). To quantify these effects, a field experiment was set up, consisting of 6 urine-diversion toilet vaults, each with a different combination of feces and bulking agent (soil, ash, wood shavings, sodium hydroxide, or straw) and ventilation (ventpipe/no ventpipe). The pH of the mixes varied from 6.37 to 10.09. Temperature probes, which were connected to a data logger, were inserted to the heaps, and the logger monitored over a period of nearly 10 months. Mean heap temperatures ranged from 16.8 degrees C in winter to 27.6 degrees C in summer. In addition, samples were taken at intervals from the various heaps in the vaults and also from an open heap exposed to the elements. The samples were subjected to microbiological testing to quantify the pathogen dieoff over time. In the vaults, there was a 3log10 (99.9%) reduction of total coliform between 130 and 250 days, fecal coliform between 100 and 250 days, and fecal streptococci from 125 days and longer. In the open heap, these times varied, from 115 days for both total and fecal coliform, to 140 days for fecal streptococci. Viable Ascaris ova were reduced to zero between 44 and 174 days in the vaults and by 44 days in the open heap. The results of this research showed that ventilation of the vault by means of a ventpipe does not result in any meaningful difference in the vault temperature or the rate of pathogen dieoff. While the type of bulking agent used does not significantly affect the temperature of the heap, it does have an effect on the rate of pathogen dieoff. The ordinary soil mix was seen to give the best results, and this was ascribed to the effect of competing microorganisms in the soil itself. It is concluded that, for safety, vaults of urine-diversion toilets should be sized for a storage period of 9 to 12 months from the last use.  相似文献   
45.
This article investigates how remotely sensed lawn characteristics, such as parcel lawn area and parcel lawn greenness, combined with household characteristics, can be used to predict household lawn fertilization practices on private residential lands. This study involves two watersheds, Glyndon and Baisman’s Run, in Baltimore County, Maryland, USA. Parcel lawn area and lawn greenness were derived from high-resolution aerial imagery using an object-oriented classification approach. Four indicators of household characteristics, including lot size, square footage of the house, housing value, and housing age were obtained from a property database. Residential lawn care survey data combined with remotely sensed parcel lawn area and greenness data were used to estimate two measures of household lawn fertilization practices, household annual fertilizer nitrogen application amount (N_yr) and household annual fertilizer nitrogen application rate (N_ha_yr). Using multiple regression with multi-model inferential procedures, we found that a combination of parcel lawn area and parcel lawn greenness best predicts N_yr, whereas a combination of parcel lawn greenness and lot size best predicts variation in N_ha_yr. Our analyses show that household fertilization practices can be effectively predicted by remotely sensed lawn indices and household characteristics. This has significant implications for urban watershed managers and modelers.  相似文献   
46.
Polycyclic aromatic hydrocarbons (PAHs) have long been recognized as important environmental toxicants. Despite a plethora of information on the fate and effects of parent PAHs, relatively little is known about the environmental fate and toxicity of ketone- and quinone-substituted PAH oxidation products (termed oxy-PAHs), particularly in the aquatic environment. This study begins to fill that gap using embryos of the Japanese medaka (Oryzias latipes) as a model species. The genotoxic potential of two environmentally relevant oxy-PAHs, acenaphthenequinone and 7,12-benz[a]anthracenquinone, was assessed using the comet assay. We found that both oxy-PAHs could cause significant increases in DNA damage after only 48 h of exposure at the lowest concentrations tested (5 μg/L). Comparisons of the genotoxic potential between these oxy-PAHs and their corresponding parent PAHs (acenaphthene and benz[a]anthracene) and a well-known mutagenic PAH, benzo[a]pyrene, indicated similar potencies among all five of these compounds, particularly after longer (7 day) exposures. This study demonstrates the mutagenic potential of oxy-PAHs to an in vivo fish embryo model and points out the need for further study of their environmental occurrence and biologic effects.  相似文献   
47.
ABSTRACT: A study of 222Rn concentrations in the water distribution system of Tucson, Arizona, revealed levels of 60 to 1260 pCi/L in domestic waters. These measurements are comparable to levels of between 80 and 1400 pCi/l for 222Rn found in ground water samples in the North-Central Tucson basin (Kahn et al., 1994). Estimated loss of 222Rn due to radioactive decay during travel from the well head to the home ranges from 8 to 50 percent.  相似文献   
48.
ABSTRACT: A flood control reservoir protects valuable developments on the downstream flood plain by storing flood waters and releasing them at a rate that will reduce the downstream damage. The water surface level of the flood pool behind the dam can fluctuate considerably during the occurrence of a large magnitude flood causing severe impacts on shoreline vegetation and water based recreation facilities located in the flood pool. A mathematical simulation model describing shoreline vegetative succession in response to flooding is presented. Plant species are grouped into ecologically similar compartments. Differential equations describing compartment intrinsic growth, intraspecies competition, interspecies competition, and other growth limiting factors are solved numerically. The model is used to evaluate the impacts of various operating policies on plant succession for a new reservoir in Central Iowa.  相似文献   
49.
Using ecological criteria to evaluate wilderness planning options in Idaho   总被引:1,自引:0,他引:1  
Legally designated wilderness areas are acknowledged to be an important element in strategies to conserve biological diversity in United States. However, because of the restrictions on consumptive uses in wilderness, their establishment is normally contentious. Criteria for establishment have typically been associated with opportunity and aesthetic and experiential values. Biological data have not normally played a major role in guiding wilderness establishment. We present four wilderness allocation options for those public lands considered suitable for wilderness designation in Idaho. These options cover the span of choices presently available to wilderness planners in the state and range from not establishing any new wilderness areas to the inclusion of all suitable lands in wilderness. All options are evaluated using spatial biological data from the National Biological Survey's Gap Analysis Project. A conservation strategy that would protect a minimum of 10% of the area occupied by each of 113 native vegetation types and at a minimum 10% of the distribution of each of 368 vertebrate species was evaluated for each option. Only the inclusion of all suitable lands in wilderness, creating a system of 5.1 million ha came close to achieving these goals, protecting 65% of the vegetation types and 56% of the vertebrate species. We feel this approach, which allows planners to evaluate the ecological merits of proposed widerness units along with other values, can provide a means to resolve the impasse over additional wilderness designation in Idaho.  相似文献   
50.
ABSTRACT: A test of the suitability of subsurface drip irrigation (SDI) for alfalfa (Medicago sativa L) compared to a sprinkler, was conducted on a Kansas producer's field where the soil is loam. The treatments included drip tape spacing of 60, 40, and 30 inches placed at depths of 18 and 12 inches. A nearby plot irrigated by a center pivot sprinkler was seeded to alfalfa and used for comparison. Seedling emergence and yield were adversely affected at 60 inch spacing, while the depth of placement of drip tapes (18 and 12 inches) showed no effect on yield. The site served for education and allowed comparison between SDI tape spacing and center pivot system.  相似文献   
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