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231.
New emergy indices for sustainable development   总被引:4,自引:0,他引:4  
The emergy indices for the evaluation of system‘ s sustainable development ability were studied. Results indicated that the emergy indices are simplified and merged, and a new emergy index for sustainable development(EISD) is deduced. Employing EISD, two cases areconducted. The first one is to compare three different dike-pond agro-ecological engineering modes, which are: melon-melon-cabbage-four domestic fishes (mode I ), melon-melon-cabbage-pig-four domestic fishes (mode H ) and melon-melon-cabbage-pig-four domestic fishes combined with Siniperca chuatsi B. ( mode Ⅲ ).The result is that the EISD of mode I is 0.53. Mode Ⅱ‘ s EISD is 5.26 times of mode I ,and mode Ⅲ‘s EISD is 6.83 times of mode I The second one is to evaluate the development of Zhongshan City, Pearl Delta, during 1996 to 2000.The result indicated that the EISD of Zhongshan had appreciably declined from 1996 to 1998, and quickly improved from 1998 to 2000, partly because of its environment protection and product construction. Both of the two cases studies showed that EISD can assessment the sustainable development ability more roundly, with the consideration of environmental impact and social-economic effect at the same time.  相似文献   
232.
水文变异条件下的黄河干流生态径流特征及生态效应   总被引:1,自引:1,他引:0  
黄河流域地表水文过程受气候变化与如水库拦蓄等人类活动的严重影响,发生显著变化,多次出现断流现象。深入理解水文变异条件下的径流特征及生态效应,对于黄河流域水资源管理及水资源可持续开发利用具有重要意义。基于此,论文利用多水文指标研究水文变异过程,结合基于流量历时曲线(FDC)的生态剩余和生态赤字等生态径流指标以及水文变异总体评价指标Do和DHRAM(Dundee Hydrological Regime Alteration Method)来描述黄河干流大中型水利工程对下游河道水文情势的改变程度,并根据多样性指标SI和IHA(Indicators of Hydrologic Alteration)的拟合关系,进一步分析水文变异的生态效应。研究表明:1)水文情势变异后,FDC整体下移,低于25% FDC流量部分大幅增加,产生生态赤字;2)从上游到下游,降水对各站生态径流指标的影响逐步减小,水库对生态径流指标的影响愈益增大;3)各生态径流指标与大部分IHA指标具有较好的相关关系,能够体现IHA参数的主要信息,可作为衡量黄河流域年和季节径流变化的生态径流指标;4)综合Do和DHRAM的评价结果,径流过程变异对各站生态风险的影响为:花园口、孙口和利津站为高风险,头道拐和兰州为中等风险,唐乃亥和龙门为低风险;各水文站SI值在20世纪80年代之后均出现下降趋势,其中花园口、孙口和利津3个站的下降幅度较大,生物多样性锐减。  相似文献   
233.
The effect of Bonny light crude oil was assessed in adult albino rats. The rats were administered with 200, 400, and 800?mg/kg of the crude oil orally for 7 days. Fluid intake was measured daily, and the initial and final animal body weight recorded. Oral crude oil at these doses produced no effect on feed and fluid intake between the test groups and the control group. There was a significant decrease in body weight compared to the control group after 7 days of treatment with the different doses of crude oil.

The toxic effects of the liver and hematological effects were assessed. The packed cell volume (PCV) and total white blood cell (WBC) of the 200?mg/kg group were significantly decreased compared to the respective control values. Administration of 200, 400, and 800 mg/kg of Bonny light crude oil, caused a significant dose-dependent increase in glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) levels, but a significant decrease in the alkaline phosphatase (AP) level compared to the control. Histological examination indicates that crude oil induced severe pathologic changes in the forms of necrosis and oedema.  相似文献   
234.
Y. Li  B. Chen  Z.F. Yang   《Ecological modelling》2009,220(22):3163-3173
Ecological network analysis (ENA) is introduced in this paper as a promising approach to study water use systems. Information indices from ENA involving total system throughput (TST), ascendency and overhead are calculated here. Two related aspects including organization inherent in system structures and synthesized water use intensity related with sustainable development of water use systems are analyzed. The indices of ascendency and overhead are applied for analyzing and characterizing water use network organization. For comparison of sustainability of water use systems from integrated aspects of environment, society and economy and based on TST, a new indicator termed as total system throughput intensity (TSTI) is constructed incorporating parameters of land, precipitation, population, GDP and environmental flow, which can be used as a measure of sustainability in terms of synthesized water use intensity. The Yellow River Basin in China during 1998–2006 is chosen as the case study and divided into subsystems according to the six river sections as from source to Lanzhou (S1-L1), Lanzhou to Toudaoguai (L1-T), Toudaoguai to Longmen (T-L2), Longmen to Sanmenxia (L2-S2), Sanmenxia to Huayuankou (S2-H) and Huayuankou to the mouth of Bo Sea (H-B). The results show that (i) the organization levels of L1-T and H-B are better than those of S1-L1 and T-L2, with those of L2-S2 and S2-H the worst; (ii) the synthesized water use intensity has been improving, of which T-L2, L2-S2 and S2-H are at the highest levels while H-B the lowest. In addition, the comparison between TSTI and other metrics and the relationship between ascendency and TSTI are discussed, from which the importance of TSTI is reflected and the optimization criterions for sustainable development of six subsystems are derived. It can be concluded that the application of ENA in water use systems can provide new angles for water resource management to address the challenges of assessing and optimizing options to obtain more sustainable water use.  相似文献   
235.
干旱区绿洲土壤盐渍化程度遥感定量评价   总被引:3,自引:0,他引:3  
土壤盐渍化是制约渭干河-库车河三角洲绿洲内部植被生长最主要的生态环境地质问题,也是影响区域农业生产的第一障碍性问题.利用Landsat TM遥感数据,构建了多维向量空间下的11个遥感定量指标.首先,采用因子分析方法分析不同程度的盐渍化与这11个指标之间的相关性,并建立因子得分模型.其次,采用Fisher逐步判别分析法从这些指标中筛选出8个与盐渍化程度密切相关的指标:氧化铁、归一化盐分指数、地表反照率、植被指数、TM1、TM5、地表温度、湿度指标,并对这些指标建立判别方程,然后对渭干河—库车河三角洲绿洲典型样区盐渍化程度进行评价,将所有的实地样本分别代入判别方程,通过分析,发现判别方程的精度较高,与实际情况较吻合.轻度盐渍化的判别精度为80.3%,中度盐渍化的判别精度为68.75%,重度盐渍化的判别精度为83.65%.中度盐渍化土地的判别精度与轻度盐渍化、重度盐渍化土地的判别精度相比较低,这与中度盐渍化的光谱特征与其它地物易混淆有关.总之,所选取的指标简单,易于获取,有利于盐渍化的定量分析与评价.  相似文献   
236.
Nine similarity indices based on phytoplankton community structure were examined for their sensitivity to assess different levels of eutrophication. Two phytoplankton data sets, one from an open coastal system and one from a semi-enclosed gulf, associated with different nutrient dynamics and circulation patterns were used for evaluating the indices. The results have shown that similarity indices, measuring interspecific association and resemblance of phytoplankton communities between enriched areas and control sites, were effective for detecting spatial and temporal dissimilarities in coastal marine ecosystems. The structure of the oligotrophic habitat as a potential source of ambiguity for the results was discussed, whereas the validity ranges and the potential applicability of this method were deemed to be dependent on the size of the fraction of the common species among the samples, and the similarity of the classification patterns resulted from this subcategory and those extracted from the overall community data. Furthermore, the study provides a new technique based on the use of the “Box and Whisker Plot” designed to distinguish opportunistic and rare phytoplanktonic species. The similarity indices, applied solely to the dominant species abundance, were more sensitive to resolve eutrophic, mesotrophic and oligotrophic conditions. This procedure can be proposed as an effective methodology for water characterization and can also be used as a qualitative tracer for detecting renewal processes of coastal marine ecosystems.  相似文献   
237.
A critique of EPA's index of watershed indicators   总被引:4,自引:0,他引:4  
Numerous indices have been developed to assess water quality and the impact of programs to improve quality. The Index of Watershed Indicators (IWI) is one such index created by the US Environmental Protection Agency to assess watershed vulnerability and condition in the United States. The credibility and applicability of subjective indices such as IWI depends upon their ability to withstand tests that challenge their internal consistency and interpretation. This paper critiques IWI on the basis of these tests and other considerations, and suggests that explicitly basing the index on multiattribute utility theory and methods could help resolve many of these difficulties.  相似文献   
238.
基于P-S-R模型的焦作市生态安全评价   总被引:1,自引:1,他引:0  
文章基于焦作市社会、经济及生态环境现状分析,借鉴压力-状态-响应(P-S-R)模型,运用层次分析法构建一个涵盖指标层、因素层、准则层及目标层等4层次的城市生态安全评价指标体系。在用熵权法确定各指标权重的基础上,结合时间趋势法评价焦作市2001~2007年的生态安全状况。结果表明:2001~2003年间生态安全综合指数值分别为0.277 7、0.384 5、0.505 3,表示生态安全水平较低;2004~2007年间生态安全综合指数值在0.573 5~0.683 1之间,生态安全有所提高。整体来看,近些年来,焦作市的生态安全水平呈现不断好转态势。该研究可为了解焦作市生态安全现状,及其未来生态环境质量改善和生态安全规划管理提供依据。  相似文献   
239.
The high population and concrete environment alter urban areas by changing temperature, rainfall runoff, and water resource utilization activities. This study was conducted to investigate the water quality features of the Yongding Diversion Channel in Beijing, China, and its relationship with rainfall and urban development. Monthly water quality data were obtained from April to October of 2004 at monitoring sites of Sanjiadian, Gaojing, Luodaozhuang, and Yuyuangtan. The monthly water quality grades from 2007 to 2011 were also investigated and compared with those of other rivers. Dissolved oxygen and pH showed greater decreases after one or two moderate rainfall events than several light rainfall events. The potassium permanganate index (CODMn), ammonia nitrogen (NH3-N) and total phosphorus (TP) increased more after several light rainfall events than after one or two moderate or heavy rainfall events. Pollutant concentrations (CODMn, NH3-N, TP) in downstream regions showed greater changes than those in upstream areas after heavy rainfall events. Intense human activities around the channel greatly influenced the water quality of the channel in rainy season because of runoff pollution; however, heavy rainfall had a strong dilution effect on the pollutant concentrations in rivers. Overall, urban development has obviously deteriorated the water quality of the Yongding Diversion Channel as indicated by an increase in the water quality index from 3.22 in 2008 to 4.55 in 2010. The Pearson correlation between monthly rainfall and water quality indices from 2007 to 2011 ranged from 0.1286 to 0.6968, generally becoming weaker as rainfall and rainfall runoff became more random and extreme.  相似文献   
240.
The ability of a nitrifying sludge to oxidize p-cresol was evaluated in a sequential batch reactor (SBR). p-Cresol was first transformed to p-hydroxybenzaldehyde and p-hydroxybenzoate, which were later mineralized. The specific rates of p-cresol consumption increased throughout the cycles. The bacterial population dynamics were monitored by using denaturing gradient gel electrophoresis 0DGGE) and sequencing of DGGE fragments. The ability of the sludge to consume p-cresol and intermediates might be related to the presence of species such as Variouorax paradoxus and Thauera mechernichensis, p-Cresol (25 to 200 mg C/L) did not affect the nitrifying SBR performance (ammonium consumption efficiency and nitrate production yield were close to 100% and 1, respectively). This may be related to the high stability observed in the nitrifying communities. It was shown that a nitrifying SBR may be a good alternative to eliminate simultaneously ammonium and p-cresol, maintaining stable the respiratory process as the bacterial community.  相似文献   
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