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11.
In this laboratory study different combinations of bed (sand, pebble gravel [gravel], and a mix of sand and gravel) and flow (typical and overtopping) were experimented with to investigate the impact of porous deflectors in flow diversity, water quality, and fish performance in prismatic open channels. Deflectors changed the gradually varied flow to a rapidly varied flow, as a sudden change in the water depth was observed at the deflectors, and this change was large for smooth beds. With the presence of gravel, the scouring near the downstream deflector was almost twice that of the sand bed, and with the scouring at its own upstream deflector, irrespective of whether the flow was typical or overtopping. This behavior was a result of sand mobilization due to shear stress and sand mobilization aided gravel transport. The mixed bed showed less gravel movement compared to the gravel-only bed. The percentage of sediment washed out was minor for all bed scenarios, indicating that sediment transport was local. Relative to the sand bed without deflectors (representing a typical urban canal), deflectors resulted in reduced and improved water quality (in terms of sediment load) for sand, and mixed bed, respectively. The fishes found refuge and were comfortable in the pool areas created by deflectors unlike in channels without deflectors where they showed exhaustion.  相似文献   
12.
In the Lister region in the southern part of Norway, attempts are currently being made to facilitate for a green shift. The paper discusses two different approaches towards such a challenge. The first is procedural, where success or failure hinges on the methods applied in the effort to convince locals to incorporate climate considerations. The alternative is to reflect upon how a green ideology blends into pre-existing ideological elements in the region. It is claimed that an important reason for the failure so far to place the environment at the core of regional development, is that too much emphasis has been put on the first approach, on procedure and dialogue, whereas few efforts have been made to understand the structure of the discursive terrain in the region. What prevents a green shift has less to do with methods and is more connected to the dominance of a logic of economic growth and the fact that locals are confident that nature is already dealt with in a sensible manner. The conclusion is that we need to understand what people are concerned about and what prevents them to change, before we start telling them how to think and do development.  相似文献   
13.
Worldwide, invasive species are a leading driver of environmental change across terrestrial, marine, and freshwater environments and cost billions of dollars annually in ecological damages and economic losses. Resources limit invasive‐species control, and planning processes are needed to identify cost‐effective solutions. Thus, studies are increasingly considering spatially variable natural and socioeconomic assets (e.g., species persistence, recreational fishing) when planning the allocation of actions for invasive‐species management. There is a need to improve understanding of how such assets are considered in invasive‐species management. We reviewed over 1600 studies focused on management of invasive species, including flora and fauna. Eighty‐four of these studies were included in our final analysis because they focused on the prioritization of actions for invasive species management. Forty‐five percent (n = 38) of these studies were based on spatial optimization methods, and 35% (n = 13) accounted for spatially variable assets. Across all 84 optimization studies considered, 27% (n = 23) explicitly accounted for spatially variable assets. Based on our findings, we further explored the potential costs and benefits to invasive species management when spatially variable assets are explicitly considered or not. To include spatially variable assets in decision‐making processes that guide invasive‐species management there is a need to quantify environmental responses to invasive species and to enhance understanding of potential impacts of invasive species on different natural or socioeconomic assets. We suggest these gaps could be filled by systematic reviews, quantifying invasive species impacts on native species at different periods, and broadening sources and enhancing sharing of knowledge.  相似文献   
14.
In contradistinction to the ideas of Lynn White and others who have long suggested that the Judeo-Christian tradition fosters a ‘dominion over nature’ ethos, a number of scholars have recently argued that there has been a ‘greening of Christianity’. Largely missing from this debate is strong evidence at the individual level as to whether Christians have in fact adopted deeper environmental concerns over time. This study provides such evidence through an examination of longitudinal data from Gallup’s annual surveys on the environment. The analysis reveals little evidence that Christians have expressed more environmental concern over time. In fact, across many measures, Christians tend to show less concern about the environment. This pattern holds across Catholic, Protestant and other Christian denominations and for differing levels of religiosity. These findings support a conclusion that there has not been a discernible ‘greening of Christianity’ among the American public.  相似文献   
15.
水环境系统脆弱性是水资源利用与生态环境研究的热点问题,通过研究水环境系统的内在机理,综合考虑影响水环境系统脆弱性的资源、环境、经济、社会等因素,借助驱动力-压力-状态-影响-响应-管理(DPSIRM)框架构建水环境系统脆弱性评价指标体系。在此基础上,构建基于变权灰色云模型的评价方法,对2004~2014年江苏省水环境系统脆弱性进行评价。结果表明:2004~2014年水环境系统脆弱性指数由47.056提高到63.210,脆弱性等级由“重度脆弱”演化为“中度脆弱”,并长期维持在“中度脆弱的”等级,2014年出现了向“轻度脆弱”状态转变的趋势。分析各个子系统对水环境系统脆弱性影响程度可知,影响子系统和响应子系统对江苏省水环境脆弱性系统的影响程度逐年增加;而压力子系统和管理子系统对水环境系统脆弱性的影响程度逐年下降;其它子系统对水环境系统脆弱性的影响维持在一定水平小幅度波动。  相似文献   
16.
实施排污许可制度,是强化排污者责任、提高固定污染源环境管理效能、改善环境质量的重要制度保障。火电行业作为典型的高架固定源,先行试点实施排污许可制度。通过分析火电行业发展和环保现状,结合排污许可管理要点,简述排污许可制对火电行业发展的影响。  相似文献   
17.
ABSTRACT

Sketch-map-facilitated interviews were conducted in 23 villages in two adjacent regions in the southern Yucatan Peninsula of Mexico – the Maya (and increasingly Mennonite) forest-agriculture mosaic of the Chenes, and the late-20th-century-settlement forest frontier of Calakmul – to determine the frequency and typology of local-scale reserves, including the external (e.g. Payments for Environmental Services programs) and internal sources of their generation. 9% of the study communities are found to satisfy the author’s criteria for deliberate, autochthonous reserves. The static polygon reserve and static map are found to have limited value for understanding the evolving cultural ecologies of these regions. Alternative approaches are discussed, particularly those employed by geographers.  相似文献   
18.
根据长三角空气质量区域预报工作的实际需要,对分区文字预报和落区图预报两种方式分别制定了不同的空气质量指数级别预报准确性评估方法。分区文字预报根据设定的预报准确性判定方法计算预报评分,落区图预报按区域内预报准确城市占比进行准确率统计。分区文字预报结果显示,2017年长三角区域的预报准确天数占比为62.2%,预报评分为70.2,区域预报评估效果良好。落区图预报评估结果显示,预报级别偏差具有地域性差异,安徽北部、江苏北部和江西中北部预报等级偏高,长三角中南部沿海城市预报等级偏低。该套评估方法可为区域空气质量预报偏差成因分析提供依据,为区域预报工作的改进提供定量参考。  相似文献   
19.
环境预警制度蕴含了一项使行政权力合法扩张的"对应性架构",即预警级别与"强制型"或"限制型"措施之间的充分必要关系。在制度运行过程当中,环境行政权力却出现了"选择性失语"和"运动式肆意"的问题,具体表现为:一是预警级别发布时的"隐匿"与"从轻",从而对公民健康权益保护不足;二是预警状态下环境行政权力的扩张过度,使得对个人自由与企业经济自由侵害过度。由于环境治理领域"被害人-加害人"二元对立关系的模糊化、趋同化甚至同一化,传统公法学体系中的权力制约理论无法对预警状态下多样化和多层次性的行政权力进行有效地规制。那么,便有必要对现有的环境预警制度进行修正与纠偏。因此,可以从"对应性架构"的载体及其前后两端入手,对环境预警制度进行法治化建构。具体而言,对环境预警的载体"应急预案"进行形式改造,提高环境应急预案的规范层级,完善环境应急预案制定、修改等程序性规定;明确不同预警级别设定的规范层级,将作为被宪法所保护的客观利益——生态环境利益与经济利益的边界——通过"前端"预警标准予以划分;对预警状态下行政权力的"外部"制约程序予以完善。基于预警级别标准体系的划分,可以通过司法程序对"后端"环境应急预案进行"附带性审查",同时,赋予私主体直接针对预警状态下具有"外化"法效力的内部行政行为提起行政诉讼的诉权。  相似文献   
20.
为了解决吸附速率拟合公式缺乏而解吸经验公式众多的问题,通过替换解吸参数、定性和对比分析各经验公式对煤吸附CO2,N2,CH4吸附速率的适用性,选取4种不同煤质的煤样在0.5,1.0和2.0 MPa下进行定温吸附实验,分析压力和煤质对吸附速率的影响规律。研究结果表明:时间函数式对3种气体在不同压力和煤质下的吸附速率拟合效果最佳;压力和煤质对3种气体吸附速率的影响既存在共性又具有差异性,气体吸附速率与压力符合指数函数关系,与挥发分呈现出二次函数关系,并且压力升高会导致最低吸附速率趋向于较高变质程度煤样;CH4和N2的吸附速率随压力升高而升高,而CO2的吸附速率因煤样而不同,且在同压下,不同气体的最高和最低吸附速率煤样的变质程度也不同。  相似文献   
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