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831.
Knowledge of what conservation interventions improve biodiversity outcomes, and in which circumstances, is imperative. Experimental and quasi-experimental methods are increasingly used to establish causal inference and build the evidence base on the effectiveness of interventions, but their ability to provide insight into how and under what conditions an intervention should be implemented to improve biodiversity outcomes faces limitations. A suite of attribution methods that leverage qualitative methods for causal inference is available but underutilized in conversation impact evaluation. This article provides a guide to 5 such qualitative attribution methods: contribution analysis, process tracing, realist evaluation, qualitative comparative analysis, and most significant change. It defines and introduces each method and then illustrates how they could be applied through a case study of community conservancies in Namibia. This guide provides examples of how qualitative attribution methods can advance knowledge of what works, in which contexts, and why in biodiversity conservation.  相似文献   
832.
Two new methods for assessing temporal trends in stream-solute concentrations at specific streamflow ranges were applied to long (40 to 50-year) but sparse (bi-weekly to quarterly sampling) stream-water quality data collected at three forested mesoscale basins along an atmospheric deposition gradient in the northeastern United States (one in north-central Pennsylvania, one in southeastern New York, and one in eastern Maine). The three data sets span the period since the implementation of the Clean Air Act in 1970 and its subsequent amendments.Declining sulfate (O 4 2-) trends since the mid 1960s were identified for all 3 rivers by one or more of the 4 methods of trend detection used. Flow-specific trends were assessed by segmenting the data sets into 3-year and 6-year blocks, then determining concentration-discharge relationships for each block. Declining sulfate (O 4 2-) trends at median flow were similar to trends determined using a Seasonal Kendall Tau test and Sen slope estimator. The trend of declining O 4 2- concentrations differed at high, median and low flow since the mid 1980s at YWC and NR, and at high and low flow at WR, but the trends leveled or reversed at high flow from 1999 through 2002. Trends for the period of record at high flows were similar to medium- and low-flow trends for Ca2++ Mg2+ concentrations at WR, non-significant at YWC, and were more negative at low flow than at high flow at NR; trends in nitrate (NO3 -), and alkalinity (ALK) concentrations were different at different flow conditions, and in ways that are consistent with the hydrology and deposition history at each watershed. Quarterly sampling is adequate for assessing average-flow trends in the chemical parameters assessed over long time periods (∼decades). However, with even a modest effort at sampling a range of flow conditions within each year, trends at specified flows for constituents with strong concentration-discharge relationships can be evaluated and may allow early detection of ecosystem response to climate change and pollution management strategies.  相似文献   
833.
光环境是城市人居条件的一项重要内容,光污染的监测主要是针对光环境。将色彩校正的方法应用于彩色CCD测量光环境亮度分布,并结合计算机图像处理技术,对不同的颜色转换矩阵进行实验分析,使得亮度计算值和实测值很好地吻合,得出图像RGB三刺激值与目标亮度的函数关系式。通过实验,对相机测量值与亮度计实测值进行对比,分析镜头渐晕现象...  相似文献   
834.
由于聚乙烯管道材质的特殊性,其损伤机理和失效模式与钢质管道有很大的不同,寻找一种有效的埋地PE管道检验方法是大家关心的问题。本文通过聚乙烯燃气管道全面检验的实践,在常规检验项目的基础上,介绍了新的资料审查方法和开挖割样的原则,提出了通过割样检验来评估埋地PE管道材质性能变化情况及原始焊口安装质量的观点;最后,针对最不利条件下的组合载荷,介绍了管壁截面稳定性校核的方法。这些方法及建议,对同行有一定的参考和借鉴意义。  相似文献   
835.
Non-point source (NPS) pollution simulation in the high-precipitation coastal areas of China is difficult because varying annual typhoon incidence leads to highly contrasting rainfall patterns in dry years and wet years. An IMPULSE (Integrated Model of Non-point Sources Pollution Processes) based NPS model of the Changtan Reservoir watershed, which is a typical high-precipitation coastal area in China, was established based on the analysis of point and NPS pollution data, a digital elevation model, and data on land-use, soil, meteorology, economy, and agricultural management practice. Pre-processed pre-rain- fall soil moisture levels were introduced during the simulation to model the effects of typhoons on hydrology. Rainfall events were simulated sequentially through the year and the model was calibrated and verified using hydrological and water quality data. Accuracy of the simulated rainfall runoff and water quality in the Changtan watershed was found to be acceptable. The study showed that the NPS modeling system could be applied to the simulation and prediction ofNPS loadings in the Changtan Reservoir watershed.  相似文献   
836.
在兰州大学半干旱气候与环境观测站(SACOL)长期观测运行的基础上,针对测量气溶胶散射特性的三波段积分浑浊度仪(TSI3563)的校准和检测问题进行了探讨.讨论了TSI浊度仪检测和校准气体的选择,零气主要使用经高效微粒空气过滤器过滤的干净空气,标准气体主要使用CO2;总结出浊度仪零气检测和标准气体检测的理论依据,每天零气检测时,散射系数的变化范围为 ,平均值范围为 ,当超出这个范围就需要进行零点设定,每3~5d进行标准气体检测时,散射系数的平均值和理论计算值的误差超出 的范围,就需要进行全校准;最后介绍了零气校准和全校准的方法.  相似文献   
837.
条件价值评估法(CVM)是旅游相关资源价值评估的重要方法,其评估结果的准确性主要由支付意愿(WTP)或补偿意愿(WTA)和总体范围扩展两者决定。目前,国内外关于CVM方法的相关研究主要是针对提高WTP(或WTA)的准确性,而关于总体范围扩展方法的相关研究较少。国外旅游相关资源价值评估总体范围主要扩展为使用者,或资源所在区域的家庭,或资源所在邻近区域的家庭;国内主要扩展为使用者,或资源所在区域的居民,或资源所在区域的就业者,或全国范围的相关居民或就业者;这些总体范围扩展方法均存在一些缺陷。论文以调查样本信息为依据,提出了一种基于旅游相关资源关注度系数(用出游小区相对旅游率表示)的非使用者总体范围扩展方法和基于游客量的使用者总体范围扩展方法,并以舟山普陀金三角景区非使用价值评估为例,以2008年为评价基准年份,进行了实证分析。结果表明:普陀金三角旅游资源非使用价值为345.83×106元/a,其中非使用者贡献159.21×106元/a,国内使用者贡献184.17×106元/a,国外使用者贡献2.45×106元/a。并与国内外各种总体范围扩展计算的结果进行对比,该结果较为合理。  相似文献   
838.
A fast, high-throughput and accurate method was developed for determination of Al, As, Ba, Cd, Co, Cr, Cs, Cu, Fe, Mn, Ni, Pb, Se, U, Zn, Sb, Sn, I and Hg in urine and serum by inductively coupled plasma mass spectrometry. The samples were directly analyzed after 1/20 (v/v) dilution in 0.4% (v/v) HNO3 and 0.005% Triton X-100. Three calibration modes were tested: aqueous and matrix matching with urine and serum. The accuracy was tested using reference materials of serum, urine and spiking. Results showed that the use of matrix matching calibration reduced the interferences and improved the recoveries for Al, Co, Pb and I in urine. The matrix matching did not affect the results considerably for serum. When serum was spiked with As, Co, Cs, Pb, U, Hg, I, Ba, Al, Cr and Ni, only matrix matching presented good recoveries. Helium was used as a collision cell gas reducing effectively polyatomic interferences for Al, Mn, Cu, Ni, Cr, Zn, As and Fe. Selection of the best internal standard was carried out for each element. The use of diluted HNO3 improved the limit of detection. Finally, the method was applied successfully in samples of urine from workers occupationally exposed.  相似文献   
839.
The photochemical degradation of tetrachlorovinphos in solvents and as a solid has been investigated. Photoproducts have been isolated and characterized by spectroscopic methods and comparison with authentic samples. The rate of phototransformation of this compound has also been studied.  相似文献   
840.
我国30年间煤矿重大事故统计数据显示,人因事故占到事故总数的90%以上。为 了更好地评述近16年间有关煤矿人因事故研究的成果,运用统计分析法,对文献计量中 关键词频率较高的事故、原因、测量方法及措施四个方面进行了综述。研究发现,矿工 的不安全行为是各类事故产生的直接原因,且矿工的行为失误占主要因素。不安全行为 的研究热点体现在对其产生原因的分析上,包括矿工的心理及生理因素分析、设备因素 、文化因素、环境因素及管理因素。在对不安全行为的防范措施分析中,主要是依据其 产生的原因进行针对性的管控。说明矿工不安全行为的研究已自成体系,并越来越向系 统化和综合化方向发展,这对降低矿难事故的发生有着深远意义。  相似文献   
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