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91.
Managing diffuse water pollution from agricultural land continues to be one of the more intractable challenges for environmental policy. The advent of the Water Framework Directive places the onus on EU member states to identify reasons why water bodies fail or are at risk of failure to meet good ecological status. In such cases, programmes of measures are to be enacted to mitigate the causes at least cost. Failing this, users may ultimately be faced with the full costs of pollution. This paper considers the scope for measures that address nitrogen and phosphorus pollution at source. Specifically the paper relates the diffuse pollution problem to the extent of over application of nitrogen and phosphorus. Data envelopment analysis applied to English cereal and dairy farmers, provides an indication of resource use and evidence of over application. This inefficiency provides a potential basis for either a least cost abatement approach using effective information and advice, or alternatively a pollution charge.  相似文献   
92.
Rate coefficients for the gas-phase reactions of Cl atoms with a series of unsaturated esters CH2C(CH3)C(O)OCH3 (MMA), CH2CHC(O)OCH3 (MAC) and CH2C(CH3)C(O)O(CH2)3CH3 (BMA) have been measured as a function of temperature by the relative technique in an environmental chamber with in situ FTIR detection of reactants. The rate coefficients obtained at 298 K in one atmosphere of nitrogen or synthetic air using propene, isobutene and 1,3-butadiene as reference hydrocarbons were (in units of 10?10 cm3 molecule?1 s?1) as follows: k(Cl+MMA) = 2.82 ± 0.93, k(Cl+MAC) = 2.04 ± 0.54 and k(Cl+BMA) = 3.60 ± 0.87. The kinetic data obtained over the temperature range 287–313 K were used to derive the following Arrhenius expressions (in units of cm3 molecule?1 s?1): k(Cl+MMA) = (13.9 ± 7.8) × 10?15 exp[(2904 ± 420)/T], k(Cl+MAC) = (0.4 ± 0.2) × 10?15 exp[(3884 ± 879)/T], k(Cl+BMA) = (0.98 ± 0.42) × 10?15 exp[(3779 ± 850)/T]. All the rate coefficients display a slight negative temperature dependence which points to the importance of the reversibility of the addition mechanism for these reactions. This work constitutes the first kinetic and temperature dependence study of the reactions cited above.An analysis of the available rates of addition of Cl atoms and OH radicals to the double bond of alkenes and unsaturated and oxygenated volatile organic compounds (VOCs) at 298 K has shown that they can be related by the expression: log kOH = 1.09 log kCl ? 0.10. In addition, a correlation between the reactivity of unsaturated VOCs toward OH radicals and Cl atoms and the HOMO of the unsaturated VOC is presented. Tropospheric implications of the results are also discussed.  相似文献   
93.
Three studies examined the impact of warnings about depleting resources. In Study 1, participants played 16 trials of a 5-person resource dilemma game with complete resource uncertainty. After trial 12, participants were told they were close to depleting the resource, and thereafter received no additional warnings. Size of harvests dropped after the warning, but rebounded within 3 trials to pre-warning levels, a pattern stronger under low harvesting variability. In Study 2, participants received warnings after trials 12 and 16 of a 22-trial game. Again, harvesting dropped after the first warning, but rebounded to pre-warning levels within 3 trials, a pattern stronger under a short-term vs. a long-term warning. Harvesting was unaffected by the second warning. In Study 3, when participants received no feedback about others' harvests, harvesting dropped after both warnings, and was lower among those led to believe the resource would last a short number of trials.  相似文献   
94.
The combined impacts of simulated increased nitrogen (N) deposition (75 kg N ha−1 yr−1) and increasing background ozone (O3) were studied using two mesotrophic grassland species (Dactylis glomerata and Ranunculus acris) in solardomes, by means of eight O3 treatments ranging from 15.5 ppb to 92.7 ppb (24 h average mean). A-Ci curves were constructed for each species to gauge effects on photosynthetic efficiency and capacity, and effects on biomass partitioning were determined after 14 weeks. Increasing the background concentration of O3 reduced the healthy above ground and root biomass of both species, and increased senesced biomass. N fertilisation increased biomass production in D. glomerata, and a significantly greater than additive effect of O3 and N on root biomass was evident. In contrast, R. acris biomass was not affected by high N. The study shows the combined effects of these pollutants have differential implications for carbon allocation patterns in common grassland species.  相似文献   
95.
Relative kinetic studies have been performed on the reactions of Cl atoms with a series of methyl alkyl esters in a 405-liter borosilicate glass chamber at (298 ± 3) K and one atmosphere of synthetic air using in situ FTIR spectroscopy to monitor the reactants. Rate coefficients (in units of cm3 molecule?1 s?1) were determined for the following compounds: methyl acetate (2.48 ± 0.58) × 10?12; methyl propanoate (1.68 ± 0.36) × 10?11; methyl butanoate (4.77 ± 0.87) × 10?11; methyl pentanoate (7.84 ± 1.15) × 10?11; methyl hexanoate (1.09 ± 0.31) × 10?10; methyl heptanoate (1.56 ± 0.37) × 10?10; methyl cyclohexane carboxylate (3.32 ± 0.76) × 10?10; methyl-2-methyl butanoate (9.41 ± 1.39) × 10?11.In addition rate coefficients (in units of 10?11 cm3 molecule?1 s?1) have been obtained for the reactions of OH radicals with the following compounds: methyl butanoate (3.55 ± 0.71), methyl pentanoate (5.41 ± 1.08), and methyl-2-methyl butanoate (4.08 ± 0.82).Using the kinetic rate data tropospheric lifetimes for the methyl alkyl esters with respect to their reactions with OH, and Cl have been estimated for typical ambient air concentrations of these oxidants.  相似文献   
96.
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98.
Over recent decades, there has been increasing levels of research dedicated to assess drivers of farm-level uptake of adaptation strategies to climate change. The main purpose of this research being to determine how policy intervention can most effectively increase adoption. This paper aims to synthesise this past research in order to scale up uptake of farm-level adaptation strategies through a composite index of potential adoption in Africa. In doing so, we review the estimated coefficients of econometric regressions in 42 case studies published in peer-review journals to identify the factors that regularly explain adoption. We find that these common factors can be grouped into seven components, that is human capital, financial resources, infrastructure and technology, social interaction and governance, food security, dependence on agriculture and attitudes towards the environment. Using national-level indicators of these seven categories, we develop a composite index to inform potential adoption and test the robustness of the index in an in-depth sensitivity analysis. The results show that the highest likelihood of adoption of farm-level adaptation strategies is in Northern African countries namely Tunisia, Egypt, Algeria and Morocco and in Southern African countries such as South Africa and Botswana. Conversely, they indicate that the lowest likelihood of adoption is situated in nations of the Sahel and Horn of Africa and in nations that have recently experienced conflict. We conclude that adoption is associated predominantly with governance, civil rights, financial resources and education. However, it is not necessarily driven by the magnitude of climate change impacts on agricultural production.  相似文献   
99.
This paper advances the understanding of managerial voice endorsement based on a self‐regulation perspective. We suggest that although managers might potentially benefit more from employees' upward voice when they are more depleted, they are paradoxically less likely to diligently process or endorse such voice under ego depletion. We draw from ego depletion theory and argue that when managers are more depleted of their self‐control resources, they will spend less cognitive effort in processing voice. In turn, they tend to reject employee voice due to status quo bias and confirmation bias. We further suggest that the detrimental effect of ego depletion on voice endorsement is stronger when the voicing employee is perceived as having low expertise. We conducted an experience sampling study surveying 62 managers about voice events they encounter at work over 10 days (Study 1) and an experiment with 198 managers (Study 2). These two studies support our hypotheses. We discuss the theoretical and practical implications of our findings.  相似文献   
100.
ABSTRACT

Emission factors for selected volatile organic compounds (VOCs) and particulate material were developed during processing of commercial grades of polyamide 6, polyamide 66, and polyamide 66/6 resins. A small commercial-type extruder was used, and melt temperatures ranged from 475 to 550 °F. An emission factor was calculated for each substance measured and is reported as pounds released to the atmosphere per million pounds of polymer resin processed. Scaled to production volumes, these emission factors can be used by processors to estimate emission quantities from similar polyamide extrusion operations.  相似文献   
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