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241.
The effectiveness of marine reserve systems constructed using different surrogates of biodiversity
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Biological sampling in marine systems is often limited, and the cost of acquiring new data is high. We sought to assess whether systematic reserves designed using abiotic domains adequately conserve a comprehensive range of species in a tropical marine inter‐reef system. We based our assessment on data from the Great Barrier Reef, Australia. We designed reserve systems aiming to conserve 30% of each species based on 4 abiotic surrogate types (abiotic domains; weighted abiotic domains; pre‐defined bioregions; and random selection of areas). We evaluated each surrogate in scenarios with and without cost (cost to fishery) and clumping (size of conservation area) constraints. To measure the efficacy of each reserve system for conservation purposes, we evaluated how well 842 species collected at 1155 sites across the Great Barrier Reef seabed were represented in each reserve system. When reserve design included both cost and clumping constraints, the mean proportion of species reaching the conservation target was 20–27% higher for reserve systems that were biologically informed than reserves designed using unweighted environmental data. All domains performed substantially better than random, except when there were no spatial or economic constraints placed on the system design. Under the scenario with no constraints, the mean proportion of species reaching the conservation target ranged from 98.5% to 99.99% across all surrogate domains, whereas the range was 90–96% across all domains when both cost and clumping were considered. This proportion did not change considerably between scenarios where one constraint was imposed and scenarios where both cost and clumping constraints were considered. We conclude that representative reserve systems can be designed using abiotic domains; however, there are substantial benefits if some biological information is incorporated. 相似文献
242.
电镀废水处理厂化学镀镍废水经常规物化处理后,仍存在低浓度、高稳态的重金属污染物,导致后续出现难处理、难生化、难达标排放的普遍技术问题.本文提出一种新型高效的臭氧预氧化破络-重金属捕集螯合深度处理技术体系,即臭氧-重金属捕集剂(O_3-SN-9)耦合体系.通过单因素静态实验,重点考察了臭氧(O_3)氧化初始pH值、氧化时间、臭氧载气流量、重金属捕集剂(SN-9)投加量等对出水总镍(Ni)去除率的影响,并探讨了臭氧氧化破络络合态Ni的途径及SN-9捕集重金属Ni的机理.结果表明,在化学镀镍废水初始总Ni浓度为2.76 mg·L~(-1),臭氧预氧化初始pH值范围为7.0~11.0,反应时间为40 min,载气流量为3 L·min~(-1),SN-9投加量为40 mg·L~(-1)的条件下,处理后出水总Ni浓度稳定低于0.1 mg·L~(-1),可达到《电镀水污染物排放标准》(DB44/1597—2015)水污染物特别排放限值中总Ni的排放限值要求.液相色谱-质谱(LC-MS)、叔丁醇(Tert-Butyl Alcohol,TBA)捕获羟基自由基(·OH)实验和傅里叶变换红外光谱(FTIR)分析表明,在臭氧预氧化破络与螯合捕集Ni前后协同耦合的高效体系中,前端臭氧氧化以间接氧化为主,直接氧化为辅;氧化进程可控制为部分氧化破络,将高稳态镍络合物氧化成易失稳的小分子Ni络合物及部分离子态Ni;后续SN-9高效螯合捕集Ni的主要官能团为巯基官能团(—SH),可从低分子易失稳的Ni络合物上竞争夺取Ni离子,或直接与游离态Ni(II)反应,形成稳定的四边形配位螯合沉淀物,从而达到去除Ni的目的. 相似文献
243.
Wisner B 《Disasters》2001,25(3):251-268
Although El Salvador suffered light losses from Hurricane Mitch in 1998, it benefited from the increased international aid and encouragement for advance planning, especially mitigation and prevention interventions. Thus, one would have supposed, El Salvador would have been in a very advantageous position, able more easily than its economically crippled neighbours, Honduras and Nicaragua, to implement the 'lessons of Mitch'. A review of the recovery plan tabled by the El Salvador government following the earthquakes of early 2001 shows that despite the rhetoric in favour of 'learning the lessons of Mitch', very little mitigation and prevention had actually been put in place between the hurricane (1998) and the earthquakes (2001). The recovery plan is analysed in terms of the degree to which it deals with root causes of disaster vulnerability, namely, the economic and political marginality of much of the population and environmental degradation. An explanation for the failure to implement mitigation and preventive actions is traced to the adherence by the government of El Salvador to an extreme form of neoliberal, free market ideology, and the deep fissures and mistrust in a country that follow a long and bloody civil war. 相似文献
244.
Soil erosion is a severe problem for many developing regions that lack adequate infrastructure to combat the problem. The
authors established a first-order method for prioritizing areas to be examined and remediated using preexisting data and expert
knowledge where data are lacking. The Universal Soil Loss Equation was applied to the Rio Lempa Basin in Central America using
geographic information systems and remote sensing technologies, and the estimated erosion rates were compared with sediment
delivery ratios. Spatial analysis indicates that agriculture on very steep slopes contributes only a small fraction to the
total estimated soil erosion, whereas agriculture on gentle and moderately steep slopes contributes a large fraction of the
erosion. Although much of the basin is in El Salvador, the greatest estimated amount of erosion is from Honduras. Data quality
and availability were impaired by a lack of coordination among agencies and across countries. Several avenues for improving
the authors’ methods are described. 相似文献
245.
The need to determine cost estimates of the hazardous effects of diseases is important in order to establish the priorities of actions for prevention and health management. The evaluation of air pollution impacts on health, based on expenditures, has been carried out, but there are obvious comparison difficulties among countries, as the health-per-capita investment varies enormously. In order to achieve a standard indicator, we applied the Disability-Adjusted Life Years (DALY) method to estimate the health burden and cost estimate due to air pollution in São Paulo, Brazil. The basic methodology was the utilization of dose–response curves of epidemiological studies conducted in São Paulo to assess air pollution and its health effects. DALY attributable to air pollution in São Paulo added up to 28,212 years annually. An indirect health cost attributable to air pollution resulted in US$ 3,222,676. This estimate refers to the children and the elderly population. These results give a preliminary and underestimated value of the burden of diseases promoted by air pollution. 相似文献
246.
247.
高压水射流粉碎的压力释放效应 总被引:1,自引:0,他引:1
高压水射流粉碎是一个对物料颗粒加压后再将压力释放的过程 ,在这一过程中由于颗粒受压存储的弹性应变能的迅速释放 ,使颗粒以拉应力形式破坏实现颗粒的压力释放粉碎。笔者的理论分析和实验研究表明 :当压力达到某一值后释放 ,可以实现颗粒的破裂粉碎 ;实现压力释放粉碎作用的应力低于材料的抗压强度 ,但高于材料的抗拉强度 ;而且压力越高 ,粉碎效果越好。该研究成果为探索高压水射流粉碎机理和粉碎实践提供了有力的依据。 相似文献
248.
249.
Cavledes CN 《Disasters》1985,9(1):70-74
From December 1982 through July 1983, Peru was plagued by disastrous consequences of El Nino/Southern Oscillation phenomenon. While the northern part of the country was devastated by torrential rains and floods, central Andean Peru endured landslides and flash floods, the southern Altiplano suffered a severe drought. Hazard preparedness was nonexistent, and official disaster relief uncoordinated and slow in coming. Administrative inefficiency magnified the stress upon the populations under disaster conditions. Provisions of disaster training from specialized international organizations is recommended as a preventive measure and as a policy to improve catastrophe-coping abilities in developing nations. 相似文献
250.