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291.
The full 1H and 13C NMR spectral characterization of alpha- and gamma-1,2,5,6,9,10-hexabromocyclododecane (HBCD) is reported in this paper. The use of various NMR experiments, an analysis of the magnitude of the NMR chemical shifts and coupling constants, and computer modeling has enabled the visualization of the three-dimensional structures for both the alpha- and gamma-diastereomers. This information may provide insight into the different behavior of the alpha- and gamma-HBCD diastereomers in the environment.  相似文献   
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Following on from an analysis by Milliman and Prince, this article considers further the relative incentives for technical change provided by different pollution control instruments. The comments involve the recognition that emission targets are typically chosen fairly arbitrarily because of regulators' lack of knowledge of abatement cost schedules. There is also a more detailed discussion of the practicability of auctioning emissions permits, as these have been less thoroughly covered in the literature than the other instruments.  相似文献   
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Discussions of municipal solid waste (MSW) management are influenced increasingly by the concept of the waste hierarchy which, broadly speaking, places landfill as the least acceptable option for dealing with MSW, followed by incineration, recycling, re-use and reduction at source. In this paper, we want to question the wisdom of applying the waste hierarchy in a region with a low population density. The hierarchy was first developed with reference to the high population density areas such as the core of the EU. However, in low population density areas the economics of the various approaches to MSW is likely to be quite different. As a result, the application of the hierarchy could place an undue economic burden on a region relative to the environmental benefits that might arise. We estimate the costs, both internal and external, of the various methods of dealing with MSW in an area with the appropriate population density, drawing on information from a wide variety of sources. We find that landfill is significantly cheaper than in high population density areas, even when account is taken of the associated externalities. In addition, it is generally cheaper than the alternative methods. As such, we conclude that landfill should not be shunned as a disposal method in low population density areas.  相似文献   
295.
The Komati Downstream Development Project (KDDP), based upon the Maguga Dam has enabled 6,000 hectares of semi‐arid lowveld, in a region with low and highly variable rainfall to be converted from subsistence to irrigated commercial farming, mainly of sugar cane. This has transformed the Swazi sugar industry from one dominated by a small number of large‐scale commercial estates to one where more than 1,500 previously impoverished small‐scale Swazi farmers have been able to enter the industry by joining farmers’ associations and creating communally managed farms. Recent changes to the EU's Sugar Protocol have undermined the financial viability of the KDDP farms and undermined food security, especially for the poorest, due to the cut in sugar prices. However, some farmers’ associations have opted to keep some of their land as irrigated home gardens, rather than convert all their land to sugar cane. This model has improved food security at a time of low sugar prices and points to a more sustainable way of using water from large scale dams than the conventional model. It is argued that the EU should target support to members of the KDDP who have taken out large‐scale loans to pay for the in‐field infrastructure and encourage all farmers’ associations to adopt the food garden model. This would enable them to continue to benefit from the irrigation through improved production of subsistence crops, whilst they diversify their commercial production into novel markets.  相似文献   
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This paper reports research into the effect on the UK environment of the deregulation of land development controls. One form of deregulation is granting advance approval to specified classes of small-scale development because they are considered inconsequential. Previous research has indicated that such ‘permitted development’ may adversely affect the natural heritage. This study systematically investigated its impact on the natural heritage of Scotland. The study canvassed the opinions of agents best placed to comment: natural heritage authority field staff, local government planners and representatives of non-governmental organizations. The results revealed concern about permitted development as a whole, and about specified classes. Despite professed concerns about sustainable development, UK planning modernization has failed to grasp the opportunity for a radical and fundamental reform of the scope of UK planning control in the context of contemporary environmental issues. Accordingly, there remains an unresolved tension between the desire to remove unnecessary state regulation of land development and the protection of the natural heritage.  相似文献   
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Providing an accurate estimate of the dry component of N deposition to low N background, semi-natural habitats, such as bogs and upland moors dominated by Calluna vulgaris is difficult, but essential to relate nitrogen deposition to effects in these communities. To quantify the effects of NH3 inputs to moorland vegetation growing on a bog at a field scale, a field release NH3 fumigation system was established at Whim Moss (Scottish Borders) in 2002. Gaseous NH3 from a line source was released along of a 60 m transect, when meteorological conditions (wind speed >2.5 m s–1 and wind direction in the sector 180–215°) were met, thereby providing a profile of decreasing NH3 concentration with distance from the source. In a complementary study, using a NH3 flux chamber system, the relationships between NH3 concentrations and cuticular resistances were quantified for a range of NH3 concentrations and micrometeorological conditions for moorland vegetation. Cuticular resistances increased with NH3 concentration from 11 s m–1 at 3.0 g m–3 to 30 s m–1 at 30 g m–3. The NH3 concentration data and the concentration-dependent canopy resistance are used to calculate NH3 deposition taking into account leaf surface wetness. The implications of using an NH3 concentration-dependent cuticular resistance and the importance for refining critical loads are discussed.  相似文献   
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