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101.
本文分析了蓄滞洪区在防洪体系中的地位及其所面临的矛盾以及国内外蓄滞洪区管理和规划的研究现状和不足 ,指出可持续发展的治水观是蓄滞洪区防洪减灾与社会发展的必然选择 ;通过对蓄滞洪区复合系统的分析 ,探讨了区内人口、社会、经济、资源及防洪减灾之间的关系 ,建立了蓄滞洪区复合系统的概念模型 ,提出了蓄滞洪区可持续发展的定义并分析了其内涵。  相似文献   
102.
利用微生物脂肪酸甲酯分析技术研究了江汉平原沉湖湖心滩G1与湖岸G2两沉积柱中微生物群落结构的垂直分布特征及其环境指示意义.结果表明:微生物脂肪酸含量与特征脂肪酸分布特征在浅层(<5m)波动较大,且与深层(5~20m)差异明显;好氧细菌、一般厌氧细菌与革兰氏阳性菌占主要优势,其相对丰度高出深层约一倍.G1位点偏还原环境,其硫酸盐还原菌及其他厌氧细菌的相对丰度与环境胁迫压力(Trans/Cis)均高于G2;与溶氧相关的环境因子,如粒径、深度等是影响其微生物群落组成的关键因子.G2位点水动力条件较强,脂肪酸总量与好氧微生物的相对优势均高于G1,而深层沉积物中总氮、N/P偏低,微生物群落组成主要受碳氮营养源,特别是氮含量的影响.为评估人类活动带来的氮磷污染对湖泊深层微生物的影响提供新的认识.  相似文献   
103.
发展生态产业是重点生态功能区实现高质量跨越式发展的重要途经,而重点生态功能区转移支付是目前为止国家对重点生态功能区唯一的具有直接性、持续性和集中性的生态保护补偿政策。本文在以往研究的基础上,采用空间计量模型探究重点生态功能区转移支付对生态产业发展的影响。以江西省为研究对象,基于2008—2018年研究数据,以县域为研究单元对生态产业发展水平进行测度,并运用空间杜宾模型探究重点生态功能区转移支付对生态产业发展的空间效应。结果表明:生态产业发展在空间上存在显著的正向自相关性,且在江西省境内呈现出西北地区高—高集聚,东南地区低—低集聚的现象;重点生态功能区转移支付的提高不仅会显著促进当地生态产业的发展,还会提高邻近地区的生态产业发展水平。  相似文献   
104.
以神农架林区木鱼镇茶山上生长的8种不同类型植物为试验材料,于晴天选择其植株上东南朝向的顶部成长叶,采用LI—COR6400便携式光合测定系统、调制叶绿素荧光成像系统(IMAGING-PAMM-Series)及双通道PAM—100测量系统(Dual-PAM-100)和常规方法研究了其叶片特征、光合性能及相互间的关系,将有助于了解神农架植物的光合生产力及其植被管理。结果表明,不同类型植物叶片的叶片特征和光合性能存在明显的物种差异。比叶重(SLW)为乔木〉灌木〉草本;气孔参数以气孔导度(Cond)差异最大;草本植物的光合能力明显高于灌木和乔木,而灌木和乔木间的差异不大;叶绿素含量(Chl)及其组分的差异较小,类胡萝卜素(Car)和花青素含量(Ant)及其与Chl的比值差异极大。不同类型植物叶片特征和光合性能指标的变异系数在7.3%~73.0%间,Chla/Chlb最小,Car/Ant最大;Chla/Chlb、基于叶温的蒸汽压亏缺(VpdL)和胞间C02浓度(Ci)dx于15%,Cond、单位鲜重Car、PSII实际量子产量和PsI非光化学能量耗散的量子产量为40%~50%,单位干重Car、Ant、Chl/Ant和Car/Ant则大于60%,其他指标在20%-40%。相关分析显示,Jpn受Cond、叶片含水量和单位干重Chl的正向调控,Ant和Car对两无决定性作用;PSII和PSI的实际量子产量依赖于ci和Chl,Car过高导致其降低;PSI的光保护受SLW的负调控及单位鲜重Chl和单位干重Car的正调控;光合机构的光损伤受Ci的负调控和Chl/Car的正调控。  相似文献   
105.
《Environmental Hazards》2013,12(4):358-368
Ambient noise levels emanating from religious activities in residential neighbourhoods are an emerging environmental problem that educes little attention from enforcement agencies and policy makers in Ghana. This paper set out to quantify religious noise exposure in urban residential neighbourhoods in the Cape Coast metropolis of Ghana. Subjective annoyance levels of residents in selected communities were determined. Noise risk zones were mapped using ARCGIS 9.3 software and surface interpolation for the data was carried out using inverse distance weighting. The results show that most (77 and 86 per cent) of the locations recorded noise levels that were above the Ghana Environmental Protection Agency maximum permissible limit for day and night, respectively. Pearson's correlation coefficient for day and night noise exposure shows strong association (0.714) at the 0.01 level. There is variability in the levels of noise for both day and night, which are rather high (standard deviation = 7.59477 and 7.94022, respectively). Generally, levels of noise exposure correlated with levels of annoyance of residents, except that the highest noise exposure was not recorded in the community where the annoyance level of residents was highest. Residential neighbourhoods within the study area largely experienced safe to tolerable levels of religious noise, although 5 per cent were within the high-risk zone. Given that the selected residential areas have high population densities, even when the dispersion of noise risk is spatially limited, it affects a large number of people who belong to different socio-economic classes.  相似文献   
106.
以六家矿WⅡN16-7综放工作面为试验地点,研究采空区氧化带漏风情况。根据采空区自燃"三带"划分标准和防火注氮技术原理,通过现场实测、数值模拟、实验室试验确定注氮防火基本参数。首先,利用热重试验方法确定采空区惰化防火指标。根据惰化防火指标,通过现场实测和数值模拟的方法分别确定采空区在注氮和不注氮情况下自燃"三带"分布。然后,根据自燃"三带"分布范围,构建氧含量分布数学模型,计算出采空区氧化带混合气体中氧含量的平均值。最后,基于以上参数,通过反演计算得到采空区氧化带漏风量。计算结果表明,采空区氧化带内漏风量为15.12 m3/min,约占总供风量的2.1%。  相似文献   
107.
Fire Management of California Shrubland Landscapes   总被引:2,自引:0,他引:2  
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108.
Asulam is often applied from the air to control bracken. This herbicide affects other ferns and spray drift could affect their survival. This paper discusses the use of bioassays to assess drift (a) spatially around a single bracken patch, (b) downwind from sprayed areas, and (c) spatially in undulating terrain and with different vegetation cover types. The aims were to develop policies to protect sensitive habitats. It is suggested that “no-spray” buffer zones in excess of 160–180 m are needed to minimise risk. Protection of rare ferns from overstorey vegetation or from steep slopes did not occur. Although less drift was found upwind there was significant damage at the end of the helicopter runs because of errors in switching the sprayer on and off.  相似文献   
109.
Recent discussion of Enterprise Zones in England has been concerned with attributing development to the financial package of incentives operating, rather than the simplified planning régime, the author reconsiders the question of the significance of the new forms of planning procedure and suggests that, in the long term, the experiment will have lasting significance for the planning system itself.  相似文献   
110.
Numerous studies in the United States have shown that, in addition to accomplishing their primary objective of preventing or reducing non-point source (NPS) pollution, silvicultural Best Management Practices (BMPs) provide additional direct and indirect benefits. These benefits are valuable to a host of forestry-related groups because they improve forest habitat, improve the public's perception of the timber industry, and increase the overall value of the timber asset. In an effort to gauge the perceived value that forestry-related groups place on BMPs, Mississippi non-industrial private forest (NIPF) landowners (n=63), forestry consultants (n=30), and timber industry professionals (n=8) were surveyed using a combination of in-person, telephone interviews, and mail surveys in spring 2001. Each group was asked to rank 35 potential benefits from 1 to 5 (1 being least beneficial; 5 being most beneficial) according to their perceived value of the benefit. Results showed little variation in the overall mean response for all benefits among groups. In general, all groups assigned a ranking of average, more beneficial, or most beneficial to 31 of 35 (88%) potential benefits. Results indicated that, although these groups may have differing perceptions of the value of some benefits, all have a largely positive perception of the potential benefits from BMPs.  相似文献   
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