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1.
运用总量平衡分析法,通过研究天津经济技术开发区区域污水水量平衡,对污水中氯化物,全盐量总量组成进行定量分析,从而提出了相应的氯化物、全盐量削减措施。  相似文献   

2.
Abstract: Zieria prostrata (Rutaceae) is known from only four headlands within a 3-km stretch of coastline in New South Wales, Australia. The species was presumed to have occurred at a headland 24 km south of its present range. We used random amplified polymorphic DNA analysis to assess patterns of genetic variation within and among the extant populations. The analysis also included an individual reputedly rescued from the now extinct population. A high level of population divergence was revealed by principal coordinate analysis and an analysis of molecular variance (AMOVA; 37% among populations). Our genetic findings provide implications for the conservation management of the species. First, the loss of any one population would lead to a severe loss of genetic variation. Second, an adequate ex situ collection must sample the full range of genetic diversity from all populations. Third, the consequences of mixing populations may be an important conservation consideration if further translocations proceed. Fourth, the individual apparently sampled prior to its population extinction is genetically similar to individuals from one of the extant sites. This degree of similarity was unexpected and, after further investigation, led to the conclusion that prior existence of the species at the site is doubtful. Subsequently, a planned reintroduction program was abandoned. So far, of these four management implications, only the last has had a direct management outcome. Those implications that failed to lead to practical management outcomes did so because the same management recommendations could be obtained without genetic research. Clearly, the challenge for more effective conservation is to identify those cases in which genetic studies are likely to produce practical outcomes for conservation managers. This may be best achieved by assessing the outcomes of genetic studies already conducted.  相似文献   

3.
白光散斑法——一种较新的用于力学实验分析的方法,从其发展历程出发,简述其在40多年里的发展历史和其目前在中国国内的发展研究现状,并就其基本原理,位移信息提取的两种方法即逐点分析法和全场分析法,做了简要叙述.简单的介绍了白光散斑法的实际测量过程,并简要总结其自身独特的优势、适用的领域和其今后大体发展的趋势.图1,参27.  相似文献   

4.
该文主要采用文献资料法、测试比较法、数理统计法等方法对湖南省4所高职院校学生体质健康状况进行实地测试并且进行分析与研究.从湖南省4所高职院校学生体质健康状况中对影响学生体质健康的因素进行研究论证,并进行策略分析,其目的是为了提高高职院校学生体质健康服务.表3,参2.  相似文献   

5.
抗生素通过动物粪便或生物固体的施用、再生水灌溉进入农业土壤后可以被蔬菜和粮食作物吸收,从而引起人体的被动暴露。为了评估抗生素对人体暴露的健康风险,需要基于植物样品,发展灵敏、稳定且针对性强的分析方法。本文综述了植物样品中抗生素残留分析的研究进展,重点介绍了样品提取、净化等前处理方法及其仪器分析方法,并对植物样品中抗生素分析的研究方向进行了展望。  相似文献   

6.
The aim of the present study is to assess the present geo-environmental hazards, both flash flooding and seismic activity in the western part of Gulf of Suez. Assessment includes the analysis of satellite images, topographical, geological and other ancillary geological data using GIS technology. GIS data integration and analysis, including morphometric, local seismic activity and structural data analysis indicated that the area is under threat from two types of geo-hazards. Morphometric analysis strongly supported the high probability of flash flooding in different sites within the study area. The structural lineaments, extracted from an enhanced ETM+7 image, showed that the majority of seismic activity is related to segments of the fault system of the Gulf of Suez and the Gulf of Aqaba. The seismic activity hazard was taken into consideration through the identification of the sources of events. Seismic activity in the study area markedly increases from north to south. The distribution of the seismic activity pattern and data analysis for the study area clearly exhibits the urgent need for an assessment and rehabilitation program to mitigate geo-hazard along the existing structures.  相似文献   

7.
Beissinger SR  Peery MZ 《Ecology》2007,88(2):296-305
Reducing extinction risk for threatened species requires determining which demographic parameters are depressed and causing population declines. Museum collections may constitute a unique, underutilized resource for measuring demographic changes over long time periods using age-ratio analysis. We reconstruct the historic demography of a U.S. federally endangered seabird, the Marbled Murrelet (Brachyramphus marmoratus), from specimens collected approximately 100 years ago for comparison with predictions from comparative analyses and with results from contemporary field studies using both age-ratio analysis and conventional demographic estimators. Reproduction in the late 1800s and early 1900s matched predictions from comparative analysis, but was 8-9 times greater than contemporary estimates, whereas adult survival was unchanged. Historic reproductive rates would support stable populations, but contemporary levels should result in population declines. Contemporary demographic estimates derived from age-ratio analysis were similar to estimates from conventional estimators. Using museum specimens to reconstruct historic demography provides a unique approach to identify causes of decline and to set demographic benchmarks for recovery of endangered species that meet most assumptions of age-ratio analysis.  相似文献   

8.
抗生素通过动物粪便或生物固体的施用、再生水灌溉进入农业土壤后可以被蔬菜和粮食作物吸收,从而造成人体的被动暴露。为了评估抗生素对人体暴露的健康风险,需要基于植物样品,发展灵敏、稳定且针对性强的分析方法。本文综述了植物样品中抗生素残留分析的研究进展,重点介绍了样品提取、净化等前处理方法及其仪器分析方法,并对植物样品中抗生素分析的研究方向进行了展望。  相似文献   

9.
对传统财务业绩评价体系及其所提供的会汁信息质量进行了分析,认为财务分析应以现金流量力核心,通过现金流量指标分析企业的获利能力和支付能力更具可行性.笔者认为,以现金流量为核心,将现金流量分析指标溶于其他财务分析中,能够对企业当前存在的报表粉饰,利润操纵等现象进行充分的揭示,有助于重新构建出一套更为科学、合理的财务分析评价体系。  相似文献   

10.
Sequential analysis is an extremely powerful technique for complex samples analysis. For determination of petroleum and chlorinated hydrocarbons, the same sample is divided into two parts. One part is utilized to extract the petroleum hydrocarbons and the second part is used to extract the organochlorine compounds because petroleum hydrocarbons usually appear in higher concentrations and interfering with organochlorine compounds. This analysis method required more solvent, time, and more sample volume. The analytical strategy, in this paper, involves the use of effective and efficient but simple techniques for petroleum hydrocarbons and chlorinated hydrocarbons separation. A clean‐up procedure is presented, by which these compounds are isolated from aliphatic as well as polyaromatic hydrocarbons through a combination of HPLC and adsorption chromatography on a florisil microcolumn. Mass spectrometric identification was used as confirmation method. GLC equipped with ECD and FID for organochlorine and petroleum compounds analysis, respectively.  相似文献   

11.
华北平原土壤肥力的变化与影响因素分析   总被引:1,自引:0,他引:1  
通过对20世纪以来华北平原土壤调查数据的分析对比,揭示了从传统农业向现代农业转变的过程中土壤肥力的变化。从总体上看,冀北地区的土壤肥力有所下降,而冀南和鲁西北地区有所上升。影响肥力变化的因子包括河流治理、施肥、高产品种使用后种植制度和土地利用程度的变化等等。  相似文献   

12.
运用Fisher判别、马氏距离判别和决策树分析3种方法对61种环境优先污染物的生态危害程度进行分类,并比较了各模型的分类正确率.结果显示,决策树分析方法分类正确率最高,为92%;马氏距离判别其次,为87%;Fisher判别最低,为75%.决策树分析方法不仅减少了2项评价指标,而且对61个新数据矩阵的多次分析显示其分类能力非常稳定,正确率基本符合正态分布,且保持在92%左右,为3种方法中最优的分类方法.  相似文献   

13.
植被覆盖度与沙尘暴形成条件分析   总被引:1,自引:0,他引:1  
陈志刚  周坚华 《生态环境》2010,19(4):870-876
以归一化差值植被指数(Normalized Difference Vegetation Index,NDVI)为指标分析了我国1981年到1998年期间植被覆盖变化情况,给出了植被急剧减少产生新沙源的实例。通过对1998年4月强沙尘暴的分析,指出影响沙尘暴产生和运移的因素除了地形、风速、风向、大气稳定度外,当地植被覆盖和土壤因素也是关键因素之一。并通过对植被覆盖度(NDVI)与浮尘指数(Aerosol Index)进行定量分析,发现二者之间存在明显的负相关关系,表明植被的存在可以从一定程度上抑制浮尘现象的产生。因此,在沙尘运移路径上,采取封山封荒,植树种草,增加植被覆盖度以固结当地土壤和泥沙的措施,可以在一定程度上抑制沙尘暴灾害的发生。  相似文献   

14.
尹科  王如松  姚亮  梁菁 《生态环境》2012,(3):584-589
近年来,生态足迹作为可持续发展的有效度量工具之一,获得了广泛关注。在参阅相关文献的基础上,系统总结了生态足迹核算方法及其应用特点和趋势,结果表明,(1)在核算方法上尚存争议,目前主要的核算方法有3种:传统土地足迹法;能值足迹法;投入产出足迹法。(2)从静态足迹核算朝时间序列足迹分析和动态情景足迹预测演化。(3)尽管在各个尺度上都有应用,但生态足迹目前仅被看作是交流工具,用于决策分析的意义不大。拓展其在企业及其产品系统的应用,将是其应用价值体现的一个突破口。(4)生态足迹作为一系列指标的一部分时,发挥作用更大。(5)生态足迹应加强与现有核算体系(如GDP)的衔接,增加其被决策者接纳的可能性。  相似文献   

15.
Abstract:  Global goals established by the Convention on Biological Diversity stipulate that 10% of the world's ecological regions must be effectively conserved by 2010. To meet that goal for the mediterranean biome, at least 5% more land must be formally protected over the next few years. Although global assessments identify the mediterranean biome as a priority, without biologically meaningful analysis units, finer-resolution data, and corresponding prioritization analysis, future conservation investments could lead to more area being protected without increasing the representation of unique mediterranean ecosystems. We used standardized analysis units and six potential natural vegetation types stratified by 3 elevation zones in a global gap analysis that systematically explored conservation priorities across the mediterranean biome. The highest levels of protection were in Australia, South Africa, and California-Baja California (from 9–11%), and the lowest levels of protection were in Chile and the mediterranean Basin (<1%). Protection was skewed to montane elevations in three out of five regions. Across the biome only one of the six vegetation types—mediterranean shrubland—exceeded 10% protection. The remaining vegetation types—grassland, scrub, succulent dominated, woodland, and forest—each had <3% protection. To guard against biases in future protection efforts and ensure the protection of species characteristic of the mediterranean biome, we identified biodiversity assemblages with <10% protection and subject to >30% conversion and suggest that these assemblages be elevated to high-priority status in future conservation efforts.  相似文献   

16.
湿地价值分析及其基本原则   总被引:4,自引:0,他引:4  
在对湿地功能、用途、属性与湿地价值间的关系、湿地价值的等级性进行分析的基础上,提出了湿地价值分析的基本原则,为在规划和决策时能充分考虑湿地的真正价值,从而实现湿地资源的保护与可持续利用。  相似文献   

17.
叙述了阿特拉津的应用概况及其在生产实践中所存在问题;阿特拉津在生物体内和环境中的降解代谢过程。综述了近年来国内外在阿特拉津的残留分析方法、环境毒理学和微生物降解等方面的研究进展。  相似文献   

18.
This reassessment of the Corps of Engineers' study of the Cross-Florida Canal demonstrates the application of the Weibull probability distribution to handle uncertainty in benefit-cost analysis and illustrates the distribution's use to incorporate environmental considerations in project analysis. With range and probability assumptions to reflect the criticisms of the Corps' study, it is shown that the Canal was a high-risk project even with the inappropriately low discount rate used. Use of the Weibull distribution is shown to be superior to the usual point estimates and range sensitivity tests in benefit-cost analysis.  相似文献   

19.
针对长江上游金沙江下游区域近几年6月和10月出现的较剧烈的水资源丰枯转换现象,以2018年金沙江下游来水过程作为研究案例,考虑金沙江下游流域来水组成及水利工程建设情况,从区间流量分析及上游水库群调蓄影响分析两方面开展了研究工作。研究结果表明:金沙江下游流域丰枯转换主要影响因素为三堆子流量变化,三堆子至溪洛渡区间流量变化影响较小。在6月,上游水库群调蓄对金沙江下游流域丰枯转换影响较大,10月影响相对较小。相关研究成果可为溪洛渡-向家坝梯级水库调度计划制订及实际调度工作提供参考。  相似文献   

20.
The determination of Ce, Co, Cr, Cs, Eu, Fe, Gd, Hf, Mn, Rb, Sb, Sc, Ta, Tb, Th, Zn, Zr and Yb by instrumental neutron activation analysis in sediment samples collected from the Gulf of Gaeta (Central Tyrrhenian Sea) is described. The granulometric fractions of the sediments were grouped by cluster analysis into three granulometric facies (sand, clayey silt, and silty clay) which were then assumed to be the main factors controlling the distribution patterns of the elements. This assumption was confirmed by a discriminant analysis carried out on the trace element data.  相似文献   

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