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161.
162.
山东半岛城市群相对资源承载力与竞争力研究 总被引:4,自引:0,他引:4
以山东半岛城市群为例,采用相对资源承载力的研究思路和计算方法,计算分析了其2000-2004年相对土地资源承载力、相对经济资源承载力和综合承载力及其演化过程。研究表明:①山东半岛城市群的土地资源对综合承载力的贡献大于经济资源,是山东半岛城市群人口的主要承载资源;②山东半岛城市群的综合承载力超过实际人口数量,处于相对富余状态;③相对资源承载力的地区差异较明湿,淄博、日照处于超载状态,其它处于富余状态;④相对土地资源承载力与相对经济资源承载力的小协调发展是提升山东半岛城市群竞争力需要重点解决的问题。 相似文献
163.
Abstract: Habitat fragmentation is the transformation of once-extensive landscapes into smaller, isolated remnants surrounded by new types of habitat. There is ample evidence of impoverished biodiversity as a consequence of habitat fragmentation, but its most profound effects may actually result from functional changes in ecological processes such as trophic interactions. We studied the trophic processes of herbivory and parasitism in insect-plant food webs composed of hundreds of species in a fragmented woodland landscape. We recorded all plant species, collected mined leaves, and reared leafminers and parasitoids from 19 woodland remnants. Herbivory and parasitism rates were then analyzed in relation to woodland size and edge or interior location. Herbivory by leaf-mining insects and their overall parasitism rates decreased as woodland remnants became smaller. For each remnant the intensity of both processes differed between edge and interior. Our results provide novel evidence of the magnitude of habitat fragmentation effects, showing they can be so pervasive as to affect trophic processes of highly complex food webs and suggesting a response associated with trophic specialization of the involved organisms as much as with their trophic level. 相似文献
164.
Charles R. Kratzer Patrick L. Brezonik 《Journal of the American Water Resources Association》1981,17(4):713-715
: A data base consisting of predominantly nitrogen limited Florida lakes from the National Eutrophication Survey (NES) was used to develop a trophic state index based on total nitrogen concentration. This index was compared with Carlson's (1977) index based on total phosphorus concentration, and the lesser of the two values for each lake was averaged with indices based on Secchi disk transparency and chlorophyll a concentration to assess the trophic state of the 40 Florida NES lakes. 相似文献
165.
Ke‐Sheng Cheng Tsu‐Chiang Lei 《Journal of the American Water Resources Association》2001,37(5):1321-1334
ABSTRACT: Reservoir water quality is traditionally monitored and evaluated based on field data. Collecting and analyzing field water quality data are costly and time consuming tasks, and whether a limited number of field data truly characterize the spatial variation of the trophic state within a vast water body is often disputed. In this study we utilize Landsat TM data to estimate the water quality and trophic state of the Te‐Chi reservoir in Central Taiwan. A modified multi‐parameter model of Carlson's trophic state index (TSI) was developed for the Te‐chi reservoir. Water quality parameters (concentration of chlorophyll‐a, total phosphorous measurement, and secchi disk depth) required by the model are found to have high correlations with combinations of TM bands. Therefore, TM data are used to map the trophic state of the reservoir. TM‐derived TSI maps of the reservoir reveal that, in summer, the trophic state in the reservoir generally improves from upstream to downstream and that zones of distinct trophic state exist. A trophic state index based on secchi disk depth may give erroneous values in the upstream section of the reservoir pool due to high sediment concentration in the reservoir inflow. We conclude that the Te‐Chi reservoir is eutrophic or worse in summer and meso‐eutrophic in winter. Implementation of best management practices to reduce nonpoint source pollution in the upstream watershed is highly recommended. This study demonstrates the capability of mapping the trophic state in impounded water bodies using the Landsat TM data. 相似文献
166.
Biochemical composition and early diagenesis of organic matter in coastal sediments of the NW Adriatic Sea influenced by riverine inputs 总被引:1,自引:0,他引:1
River inputs influence trophodynamic and biogeochemical processes of adjacent continental shelves. In order to provide new insights on the influence of continental inputs on the benthic trophic state and early diagenesis of sediment organic matter we collected surface sediments in the NW Adriatic Sea at three stations located at increasing distance from the Po River. Sediment samples were collected in four periods characterized by different river outflows and analysed for chloropigment content (chlorophyll-a and phaeopygments), protein, carbohydrate and lipid concentrations, prokaryote abundance and aminopeptidase activity. Sediments of the NW Adriatic Sea displayed high organic loads, tightly coupled with the outflow dynamics of the Po River. A major flooding event was responsible of an enhanced accumulation of organic material on the sea bottom. The resulting increased nutrient load in the sediment impaired organic matter degradation processes. The results of the present study suggest that the enhanced trophic state of marine coastal sediments subjected to riverine inputs are related not only to the increased nutrient inputs, but that they may be amplified by impaired degradation processes. 相似文献
167.
Perttu Seppä Ignacio Fernández-Escudero Niclas Gyllenstrand Pekka Pamilo 《Behavioral ecology and sociobiology》2008,62(4):589-597
Establishment of new groups is an important step in the life history of a social species. Fissioning is a common mode not
only in group proliferation, for instance, as a regular part of the life cycle in the honey bee, but also when multiple females
reproduce in the same group, as in multiple-queen ant societies. We studied the genetic consequences of fissioning in the
ant Proformica longiseta, based on DNA microsatellites. In P. longiseta, new nests arise by fissioning from the old ones when they grow large, and the daughter nests consist of workers and queens
or queen pupae but never both. Our results show that fissioning is not entirely random with respect to kinship. Workers tend
to segregate along kin lines, but only when the initial relatedness in the parental nests is low. Workers in a daughter nest
also tend to be associated with closely related adult queens, whereas such an association is not detected between workers
and queen pupae. Most queens and workers are carried to the daughter nest by a specialized group of transporting workers,
suggesting active kin discrimination by them. Fissioning pattern in P. longiseta is different from that found in other social insects with regular fission (e.g., the honey bee, swarm-founding wasps), where
no fissioning along kin lines has been found. It does, however, resemble fissioning in another group of social animals: primates. 相似文献
168.
Min Yang Ashraful Islam Guangxi Sun Ayman N. Saber Wei Shang Xingcan Zheng Yu Zhang 《环境科学学报(英文版)》2022,34(12):174-183
This study provided insights into the persistent yellowish color in biological and tertiary effluents of municipal wastewater through a multi-characterization approach and fluorescence excitation-emission matrix-parallel factor (EEM-PARAFAC) analysis. The characterization was performed on three to five full-scale municipal wastewater treatment plants (WWTPs), including differential log-transformed absorbance (DLnA) spectroscopy, resin fractionation, size-exclusion chromatography for apparent molecular weight analysis (SEC-AMW), and X-ray photoelectron spectroscopy (XPS) analysis. Hydrophobic acids (HPOA) were abundant in visible colored dissolved organic matter (DOM). The SEC-AMW result showed that the molecular weight of the colored substances in the secondary effluents is mainly distributed in the range of 2–3 kDa. Through XPS analysis, C-O/C-N and pyrrolic/pyridonic (N-5) were found to be positively correlated with chroma. PARAFAC component models were built on biological (two components) and tertiary effluent (three components) and the correlation analysis revealed that PARAFAC component 2 in biological effluent (BE-C2) and component 1 in tertiary effluent (TE-C1), which were ascribed to Hydrophobic acids and Humic acid-like, were the responsible visible colored DOM components cause yellowish color. In addition, component similarity testing found that the identified visible colored DOM PARAFAC BE-C2, and PARAFAC TE-C1 were identical (0.96) in physicochemical properties, with 4% removal efficacy on average, compared with 11% for invisible colored DOM. This implied that tertiary effluents containing colorants (TE-C1) were resistant to degradation/removal using different disinfection and filtration processes in advanced treatments. This sheds light on many physicochemical aspects of PARAFAC-identified visible colored DOM components and provides spectral data to build an online monitoring system. 相似文献
169.
基于民生满意度的资源型城市转型绩效测度及群体差异研究——以湖北省黄石市为例 总被引:1,自引:1,他引:0
民生满意度评价是资源型城市转型绩效测度的终端体现,对于改善转型绩效、促进资源型城市可持续发展具有重要的现实意义。论文以民生满意度为视角,从居民生计、公共服务、民生环境、文化消费4个方面构建资源型城市转型绩效测度指标体系,采用专家群决策及AHP方法确定指标权重,运用顾客满意度评价法对黄石这一典型资源型城市转型绩效进行测度并进一步揭示被调查群体的差异特征。研究结果表明:1)基于民生满意度的黄石市转型绩效测度值为4.17,总体上处于"优秀"等级水平,但在某些局部指标上仍略显不足;2)黄石市转型绩效存在由被调查者特征而引起的群体和区域差异:不同性别、年龄、文化程度、职业类别、家庭年经济收入群体对转型民生满意度评价不同,并呈现一定规律;从区域差异来看,铁山区、大冶市等传统老矿区依托国家资源型城市转型政策支持,转型民生满意度绩效值相对较高,西塞山区、下陆区、黄石港区等中心城区历史包袱沉重、转型升级民生满意度暂时落后,以阳新为代表的农业县市,民众对于转型的认知和感受相对滞后,转型升级民生满意度居末;3)黄石市转型的民生满意度赋值与其物质产出绩效具有一致性。 相似文献
170.
基层公安消防部队应急救援能力构成要素研究 总被引:4,自引:3,他引:1
近年来,我国公安消防部队主动拓展职能,承担了灭火之外的,以抢救人民生命为主的应急救援任务,已成为了我国常态下应急救援的主力军。本文根据新时期、新形势下应急救援工作建设的实际需要,系统的研究了应急救援能力的概念和构成要素,并从人员、装备、组织管理指挥体系和社会救援资源四个方面对基层公安消防部队的应急救援能力进行了分析,对各要素及各要素之间的关系分别进行了研究,分别提出了各要素的衡量方法,可对基层公安消防部队应急救援能力的科学评价和管理决策提供参考。 相似文献