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1.
Journal of Material Cycles and Waste Management - The use of lignocellulosic fibers as fillers in polymer matrices has aroused the interest of the scientific community and industrial sectors. In...  相似文献   
2.
Journal of Material Cycles and Waste Management - This study proposes an alternative for Jatoba shell residues as reinforcement in castor oil-based polyurethane (PU), obtaining an eco-friendly...  相似文献   
3.
The Environmental Protection Agency's (EPA's) audit policy authorizes reduced penalties for firms that voluntarily undertake compliance audits and then correct and report any discovered violations to the agency. While the EPA claims the policy is a success, this paper joins a growing literature in questioning that claim. A game-theoretic model of the audit policy is developed where the goal of enforcement is remediation and the agency is unable to commit to a pre-announced inspection policy. Self-auditing is beneficial because it permits both self-reporting and self-policing to occur; however additional costs are imposed on firms. Self-auditing is more likely to be socially beneficial when the damages caused by violations are large. The current audit policy explicitly excludes violations that result in serious actual or potential harm. When violations are small, as most current disclosures under the audit policy are, firm self-auditing is likely to increase social costs.  相似文献   
4.
Feedback from 360 degree ratings based on competency principles and used for developmental purposes was investigated for interrelationships among the ratings and for its relationships with performance and selection data. Relationships among: (1) feedback ratings from supervisors, peers, and self; (2) feedback ratings and selection test data; and (3) feedback ratings and performance appraisals on about 2000 employees of a Midwestern insurance company were examined. The 360 ratings by peers and managers were related to performance appraisals. All significant correlations of manager and peer ratings with selection tests were positive, but significant correlations of 360 degree self‐ratings with selection tests were negative. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   
5.
Growth of cells from amniotic fluid was studied with respect to cell concentration in the inoculum, blood contamination of the fluid, fluid colour, fluid clarity, gestational age of the pregnancy, and growth factors. Dependent variables measured were colony formation, colony size, and colony morphology after 7, 11, and 14 days of culture. The following conclusions were established from these studies: small sample volumes are the most efficient for producing colonies; cells from very bloody or dark brown fluids have a slower rate of growth; growth of cells from cloudy (noncontaminated) fluids is better than growth of cells from clear fluids; the proportion of colonies that are epithelioid varies with gestational age; the stimulating effect of 100 ng/ml fibroblast growth factor on cells from amniotic fluid was confirmed.  相似文献   
6.
Understanding climate change and its impacts on crops is crucial to determine adaptation strategies. Simulations of climate change impacts on agricultural systems are often run for individual sites. Nevertheless, the scaling up of crop model results can bring a more complete picture, providing better inputs for the decision-making process. The objective of this paper was to present a procedure to assess the regional impacts of climate scenarios on maize production, as well as the effect of crop cultivars and planting dates as an adaptation strategy. The focus region is Santa Catarina State, Brazil. The identification of agricultural areas cultivated with annual crops was done for the whole state, followed by the coupling of soil and weather information necessary for the crop modeling procedure (using crop model and regional circulation models). The impact on maize yields, so as the effect of adaptation strategies, was calculated for the 2012–2040 period assuming different maize cultivars and planting dates. Results showed that the exclusion of non-agricultural areas allowed the crop model to correctly simulate local and regional production. Simulations run without adaptation strategies for the 2012–2040 period showed reductions of 11.5–13.5 % in total maize production, depending on the cultivar. By using the best cultivar for each agricultural area, total state production was increased by 6 %; when using both adaptation strategies—cultivar and best planting date—total production increased by 15 %. This analysis showed that cultivar and planting date are feasible adaptation strategies to mitigate deleterious effects of climate scenarios, and crop models can be successfully used for regional assessments.  相似文献   
7.
Apple snail Pomacea canaliculata has been reported to accumulate polybrominated diphenyl ethers (PBDEs) and was recently proposed as PBDE bioindicator. This work investigates the ability of P. canaliculata to accumulate BDE-209 by dietary exposure under controlled experimental conditions. A 30-day long enrichment feeding assay was carried out using 30 adult apple snails, placed in individual aquaria. Food was enriched at three BDE-209 concentrations (400, 4,700, and 8,300 μg g?1 lipid weight). Correlation between BDE-209 values in food and snail tissue were estimated according to Stockholm Convention suggested criteria for chemicals with KOW >5. All animals survived with no evident physical alterations, and all of them accumulated BDE-209. BDE-209 levels in tissue samples increased exponentially with the exposure concentration. The bioaccumulation factor vs. food concentration plot showed a peculiar pattern, in which at intermediate concentrations the snails accumulated less BDE-209 than expected. Our results suggest that P. canaliculata would present a detoxification mechanism for BDE-209 different from the most commonly reported metabolic pathways.  相似文献   
8.
Journal of Material Cycles and Waste Management - The search for environmental sustainability has stimulated the construction sector to look for natural materials with an ecological footprint, high...  相似文献   
9.
The purpose of our study is to show how ecologists' interpretation of habitat selection by grizzly bears (Ursus arctos) is altered by the scale of observation and also how management questions would be best addressed using predetermined scales of analysis. Using resource selection functions (RSF) we examined how variation in the spatial extent of availability affected our interpretation of habitat selection by grizzly bears inhabiting mountain and plateau landscapes. We estimated separate models for females and males using three spatial extents: within the study area, within the home range, and within predetermined movement buffers. We employed two methods for evaluating the effects of scale on our RSF designs. First, we chose a priori six candidate models, estimated at each scale, and ranked them using Akaike Information Criteria. Using this method, results changed among scales for males but not for females. For female bears, models that included the full suite of covariates predicted habitat use best at each scale. For male bears that resided in the mountains, models based on forest successional stages ranked highest at the study-wide and home range extents, whereas models containing covariates based on terrain features ranked highest at the buffer extent. For male bears on the plateau, each scale estimated a different highest-ranked model. Second, we examined differences among model coefficients across the three scales for one candidate model. We found that both the magnitude and direction of coefficients were dependent upon the scale examined; results varied between landscapes, scales, and sexes. Greenness, reflecting lush green vegetation, was a strong predictor of the presence of female bears in both landscapes and males that resided in the mountains. Male bears on the plateau were the only animals to select areas that exposed them to a high risk of mortality by humans. Our results show that grizzly bear habitat selection is scale dependent. Further, the selection of resources can be dependent upon the availability of a particular vegetation type on the landscape. From a management perspective, decisions should be based on a hierarchical process of habitat selection, recognizing that selection patterns vary across scales.  相似文献   
10.
Leaching of heavy metals in acid mine drainage.   总被引:1,自引:0,他引:1  
Acid mine drainage is one of the most serious environmental problems that the coal and metal mining industry is currently facing. The generation of low pH drainage enhances the dissolution of heavy metals in water. The samples used in this research originated from three pits at mine dumps. In a study reported in this paper, three types of tests; namely static test, kinetic test and column test were conducted to estimate acid generation and acid neutralization reaction rates, and to predict the solubility of metals and their release rates. Static test showed that all samples had a pH of net acid generation (NAG pH) <4, a net acid producing potential (NAPP) >10 kg H2SO4tonne(-1), and a S-content >3%, which can be classified as a high acid-forming capacity. Simulated runoff in the column tests was equivalent to 5-year average rainfall in Indonesia, the resultant leachates showed acidic behaviour (pH < 3.5). Based on the results, it was found that high mobilization of heavy metals (Cr, Cu, Zn, Cd and Pb) takes place under strong acidic conditions (pH approximately equal 2).  相似文献   
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