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421.
欧洲酸雨控制历程及效果综合评述 总被引:4,自引:0,他引:4
在分析大量文献资料的基础上,综合评述了欧洲酸雨发展和控制的主要历程. 20世纪70年代以来,欧洲酸雨控制主要经历了EMEP建立与达成共识,CLRTAP公约形成与实施平均减排方针,基于临界负荷与生态敏感性制定减排策略,以及多污染物协同控制与追求多重环境效应等4个发展阶段,并取得了显著的控制效果. 1980—2007年,欧洲硫排放减少了84%,NOx排放减少了37%;大气中ρ(SO2)从10.32 μg/m3降至1.26 μg/m3,ρ(NO2)从10.38 μg/m3降至7.15 μg/m3;欧洲降水酸度呈不断下降的趋势. 最后,基于欧洲酸雨控制先进经验的分析,结合实际情况提出了未来我国酸雨控制建议. 相似文献
422.
采用参与性评估方法,根据土地利用现状和植被情况,巴卡小寨(村级)农地景观生态可分为林地、耕地、园地、庭院、荒地5个类型11个亚类型,其中轮歇地约占小寨总面积的1/2,橡胶园约占1/4。随着人口增加,轮歇地面积减少,轮歇周期缩短,复种指数提高,轮歇地逐渐退化,生态环境恶化。橡胶园的开发,促进了经济发展,但不利于水土保持和生物多样性保护,持续发展前景不乐观。根据存在的主要问题提出了相应对策。 相似文献
423.
Summary. Research on insect migration has justifiably emphasized females – the so-called “oogenesis-flight syndrome”– since it is
the females that place the eggs into new habitats. The large and small milkweed bugs, Oncopeltus fasciatus and Lygaeus kalmii, respectively, have featured prominently in studies of insect migration and sequestration of host plant toxins for chemical
defense. Here we report that males of these species, and males of another well-studied lygaeine (Neacoryphus bicrucis), produce pheromones in glands usually considered to serve only a defensive role in Heteroptera (the metathoracic scent glands),
and that these pheromones are exploited by a tachinid parasitoid as a host-finding kairomone. The pheromones are mixtures
of C6 and C8 saturated and unsaturated esters reminiscent of lepidopteran pheromones, and the key compound of the O. fasciatus pheromone has now been correctly identified as (E)-2,7-octadienyl acetate. It is proposed that the concept of the oogenesis-flight syndrome for these kinds of insects should
accommodate the role of males in the migration process. The hypothesis is presented that male-produced pheromones play a significant
role in guiding colonization of new habitats in many heteropteran species. In addition, data are presented suggesting that
there is a trade-off between the amount of pheromone produced by colonizing males and the host breadth of the species.
Received 21 December 1998; accepted 15 February 1999. 相似文献
424.
Ivon Cuadros-Casanova Andrea Cristiano Dino Biancolini Marta Cimatti Andrea Antonio Sessa Valeria Yeraldin Mendez Angarita Chiara Dragonetti Michela Pacifici Carlo Rondinini Moreno Di Marco 《Conservation biology》2023,37(3):e14052
The Common Agricultural Policy (CAP) is the European Union's main instrument for agricultural planning, with a new reform approved for 2023–2027. The CAP intends to align with the European Green Deal (EGD), a set of policy initiatives underpinning sustainable development and climate neutrality in the European Union (EU), but several flaws cast doubts about the compatibility of the objectives of these 2 policies. We reviewed recent literature on the potential of CAP environmental objectives for integration with the EGD: protection of biodiversity, climate change mitigation and adaptation, and sustainable management of natural resources. The CAP lacks appropriate planning measures, furthering instead risks to biodiversity and ecosystem services driven by landscape and biotic homogenization. Funding allocation mechanisms are not tailored to mitigate agricultural emissions, decreasing the efficiency of climate mitigation actions. The legislation subsidies farmers making extensive use of synthetic inputs without adequately supporting organic production, hindering the transition toward sustainable practices. We recommend proper control mechanisms be introduced in CAP Strategic Plans from each member state to ensure the EU is set on a sustainable production and consumption path. These include proportional assignment of funds to each CAP objective, quantitative targets to set goals and evidence-based interventions, and relevant indicators to facilitate effective monitoring of environmental performance. Both the CAP and the EGD should maintain ambitious environmental commitments in the face of crisis to avoid further degradation of the natural resources on which production systems stand. 相似文献
425.
426.
在全球化过程中,城市群是城市化过程中出现的一种特殊的城镇空间组织形式,通过对城市群的发展研究来探讨区域经济的发展是学术界一个新的研究领域和良好的动态趋势。在对城市群的基本概念、发展阶段进行分析的基础上,提出了南昌地域城市群形成发展的动力机制,并对南昌地域城市群进行了界定。最后在对南昌地域城市群进行SWOT分析的基础上,提出南昌地域城市群发展的战略对策。 相似文献
427.
With the development of activated sludge model, the simulation software for the design and operation of wastewater treatment plant (WWTP) was produced and has been widely used. The dynamic change of the quality and flow of influent are major factors causing the unstable operation of wastewater treatment process. As a basic model, ASMI model was used for the simulation of activated sludge process, and double exponential model was selected for the simulation of secondary sedimentation tank. The influences of influent change to the aeration tank and secondary sedimentation tank were investigated, and the relationship among influent change, the quality of effluent and the level of sludge blanket in secondary sedimentation tank was established. On the basis of the simulation results, the operation of the WWTP could be adjusted under the dynamic change of the influent. Furthermore, the controlling strategy combined the feed-forward on the influent flow and the feedback on the level of sludge blanket in the secondary sedimentation tank was studied. 相似文献
428.
Emergency response is an important measure to reduce the loss of any major fire and prevent its escalation. There may be many fire trucks participating in the fire-fighting at the same time, and the scheduling of them will affect the fire-fighting efficiency and thus, capacity. This work focuses on the cycle process of fighting fire and refilling water of fire trucks, and analyzes and compares the scheduling strategies of the fire trucks. The simulation tool eM-plant is utilized to model the fire-fighting process. In view of the emergency response in relation to a chemical fire accident and to prevent its escalation, strategies in the analysis consider the allocation of fire trucks according to the distance of hydrants, the distribution of fire trucks according to the number of fire hydrants, etc. The results of this paper show that an even distribution of fire trucks leads to a good performance, but can be further adjusted to find a more optimal strategy. This study provides guidance for fire truck scheduling in case of emergency response. 相似文献
429.
430.
我国环境保护战略政策进入到推进环境质量改善和美丽中国建设的生态文明战略阶段,环境保护参与规划制定的必要性和重要性不断的显现。本文通过梳理近期在制定环境保护规划以及规划环境影响评价过程中所发现的问题,结合国土空间规划编制思路,进行在新阶段如何完善环境保护战略的探讨。 相似文献