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71.
周青 《生态环境》2007,16(5):1583-1584
环境问题本质是人的问题,具体表现于人口问题和人的德行问题。文章认为导致我们系列环境政策没有起到预想结果的原因在于我们"德行"中存在的认识误区,分析了这些认识误区;提出解决环境问题的根本途径是改造我们的"德行"并知道我们生活在地球"极限之内"。  相似文献   
72.
Repertoire size, the number of unique song or syllable types in the repertoire, is a widely used measure of song complexity in birds, but it is difficult to calculate this exactly in species with large repertoires. A new method of repertoire size estimation applies species richness estimation procedures from community ecology, but such capture-recapture approaches have not been much tested. Here, we establish standardized sampling schemes and estimation procedures using capture-recapture models for syllable repertoires from 18 bird species, and suggest how these may be used to tackle problems of repertoire estimation. Different models, with different assumptions regarding the heterogeneity of the use of syllable types, performed best for different species with different song organizations. For most species, models assuming heterogeneous probability of occurrence of syllables (so-called detection probability) were selected due to the presence of both rare and frequent syllables. Capture-recapture estimates of syllable repertoire size from our small sample did not differ significantly from previous estimates using larger samples of count data. However, the enumeration of syllables in 15 songs yielded significantly lower estimates than previous reports. Hence, heterogeneity in detection probability of syllables should be addressed when estimating repertoire size. This is neglected using simple enumeration procedures, but is taken into account when repertoire size is estimated by appropriate capture-recapture models adjusted for species-specific song organization characteristics. We suggest that such approaches, in combination with standardized sampling, should be applied in species with potentially large repertoire size. On the other hand, in species with small repertoire size and homogenous syllable usage, enumerations may be satisfactory. Although researchers often use repertoire size as a measure of song complexity, listeners to songs are unlikely to count entire repertoires and they may rely on other cues, such as syllable detection probability.Communicated by A. Cockburn  相似文献   
73.
74.
Goal, Scope and Background In order to evaluate the estrogenic activity of sediments and XAD water extracts of selected sites of the catchment area of the River Neckar, a river system in Southern Germany, an integrative assessment approach was used to assess the ecological hazard potential of endocrine-disrupting compounds in sediment and water. Methods The approach is based on estrogen receptor-mediated vitellogenin synthesis induced in isolated hepatocytes of rainbow trout and quantified in a non-radioactive dot blot/RNAse protection-assay in parallel to comprehensive chemical analyses of estrogenic substances. Results and Discussion Numerous investigated extracts revealed an estrogen activity comparable to that of the positive control (1 nM 17?-estradiol corresponding to 270 ng/L in the test medium). Based on a concentration factor of 30 in the extracts and a recovery of XAD resins of approximately 80 %, 17?-estradiol equivalent concentrations between 20 and 26.7 ng/L could be calculated downstream of a sewage treatment plant (< 0.1 ng/L for a reference site). A comparison of the bioassay-derived Bio-TEQs (toxicity equivalents) and the Chem-TEQs revealed a high correlation with a Pearson coefficient of 0.85, indicating that the same ranking of the samples could be obtained with respect to the endocrine disrupting potential with both chemical and bioanalytical analysis. However, the TEQ concentrations computed from chemical analyses were significantly lower than the bioassay-derived TEQ concentrations. In fact, in none of the samples, more than 14 % of the vitellogenin-inducing potency could be attributed to the substances (steroids, alkylphenols, bisphenol A, diethylstilbestrol) analyzed. A comparison of the endocrine disrupting potential of sediments extracted by the solvents acetone and methanol revealed lower biological effects for acetone-extracted samples. Possible reasons may be a masking of endocrine effects in acetone extracts by cytotoxicity, a low extraction efficiency of the solvent acetone, or anti-estrogen potencies of some extracted sediment compounds. Using a mass balance approach, the contribution of the compounds analyzed chemically (Chem-TEQs) to the total endocrine activity (Bio-TEQs) was calculated. Based on the very low detection limits, particularly of the steroids with their high TEF factors, results revealed that a calculation of the Chem-TEQs is associated with considerable scale inaccuracy: Whereas only 7-15 % of the biological effectiveness (Bio-TEQs) could be explained by endocrine substances identified above the detection limits, the assumption of concentrations slightly below the given detection limits would result in a significant over estimation (137-197 %) of the Bio-TEQs. Even the interassay variation of the dot blot assay with different fish donors for primary hepatocyte (factor 2 - 2.5) is relatively low, when compared to the large range of the Chem-TEQ concentrations (factor 20) obtained when applying different modes of calculation. Conclusions and Outlook Overall, only a minor portion of the endocrine activity detected by bioassays could be linked to compounds identified by chemical analysis. In vitro assays for assessment of endocrine activities are useful as sensitive integrating methods that provide quantitative estimates of the total activity of particular receptor-mediated responses. Although discrepancies may also result from different bioanalytical approaches, it is overall likely that bioanalytical and not chemical analytical approaches give the correct estimate of endocrine disrupting potencies in environmental samples. As a conclusion, assessment of endocrine disruption based on chemical analysis alone does not appear sufficient and further research into the spectrum of substances with potential endocrine activity as well as into additive or even synergistic effects in complex environmental samples is urgently needed.  相似文献   
75.
传统的"自下而上"清单方法估算的排放清单,其数据的准确性和时效性存在较大局限.基于集合均方根卡尔曼滤波的源清单反演方法,结合WRF-CMAQ(天气研究和预报模式-公共多尺度空气质量模型)被用于对以清华大学编制的2010年MEIC(中国多尺度排放清单模型)排放清单为基础制作的重庆地区SO2排放源进行反演试验以解决准确性和时效性问题,试验时间段为2014年10月15-31日,重庆主城17个环境空气质量国控监测点ρ(SO2)小时观测资料用于反演及检验.结果表明:该方法能够反演重庆地区SO2源排放量,随着反演次数增加,基于反演排放源预报的ρ(SO2)预报误差持续减小,反演4次后预报误差达到比较低的稳定的水平,其均方根误差均低于20 μg/m3. 5次反演后SO2源排放量用于2014年10月24-29日每天起始预报,其预报的站点、时间平均的均方根误差从100~400 μg/m3降至30 μg/m3以下.反演中应用局地化尺度减少集合取样误差影响,54与81 km两个局地化尺度反演结果对预报改善效果相当,表明主要影响重庆主城ρ(SO2)的源排放位于主城及周边地区,也说明内源排放对重庆主城ρ(SO2)起主要影响.反演后面源排放量主城区降幅约为30 kg/(d·km2),周边地区减少10~20 kg/(d·km2),主城区部分SO2点源排放量降幅约为25 kg/(d·km2),说明2010年MEIC排放清单高估了试验时段重庆地区的SO2排放.   相似文献   
76.
采用大涡PIV方法对Taylor-Couette流场的湍动能及湍动能耗散率进行了估算,并利用数值模拟对其进行验证,结合絮凝实验,综合对比速度矢量、湍动能分布、湍动能耗散率分布及对应流场中混凝过程的絮体图像,探究了湍动能与湍动能耗散率对絮凝效能的影响.结果表明,大涡PIV法与数值模拟在雷诺数较高的情况下有较好的一致性,且雷诺数越大一致性越好.在Taylor-Couette涡流场中,随着雷诺数的增大,湍动能与湍动能耗散率数值不断增大,且在流场中的分布由规律有序到紊乱最终趋于各向均匀一致.而混凝过程中湍动能与湍动能耗散率的数值大小及其在流场中的空间分布情况,均对产生絮体的大小和浊度去除率有较大影响.  相似文献   
77.
臭氧(O3)与甲烷(CH4)均是大气中重要的微量气体,对全球气候变化有着重要的影响.为提高全球范围的臭氧、甲烷在气候模式中的预报效果,使用集合平方根滤波(En SRF)同化方法及地球系统模式(CESM)构建了CESM-En SRF卫星资料同化预报系统,并通过设计试验,将大气红外探测器(AIRS)的臭氧与甲烷观测资料同化到气候模式中,对模式的同化再预报效果进行系统的测试与评估.结果显示,臭氧、甲烷分析集合均值的偏差及均方根误差皆低于背景集合均值的偏差及均方根误差.臭氧、甲烷的同化再预报偏差及均方根误差较控制实验都得到改善,但对5 h Pa以上高度臭氧预报准确性的改进效果很小.随循环同化的进行,平流层臭氧与甲烷的平均同化改进率呈增加趋势,并逐渐趋于稳定;对流层平均同化改进率随时间变化不明显.试验表明,该系统可有效利用臭氧与甲烷的观测资料对模式场进行合理的改善,从而有效地提高臭氧、甲烷在气候模式中的再预报效果,但对于平流层顶-中间层高度(5 h Pa以上)臭氧预报准确度的提高,模式中臭氧光化学过程的准确模拟较同化观测资料具有更重要的作用.此外,循环同化对提高5~150 h Pa高度臭氧及1~200 h Pa高度甲烷在CESM模式中的预报效果最有效.  相似文献   
78.
针对工业园区空气质量的复杂性和模糊性,利用模糊物元分析理论,结合海明贴近度的概念,建立了一种基于模糊物元的空气质量评价模型。以金山二工区为例,选取《环境空气质量标准》规定的6种主要污染物SO2、NO2、CO、O3、PM10、PM2.5作为评价指标,分析了园区内5个自动监测站2016年7月1日的环境空气质量状况,并与空气质量指数(AQI)技术分析结果作比较。两种方法的评价结果基本一致,与实际状况相符。  相似文献   
79.
Risk management can be defined as coordinated activities to conduct and control an organization with consideration of risk. Recently, risk management strategies have been developed to change the approach to hazards and risks. Resilience as a safety management theory considers the technical and social aspects of systems simultaneously. Resilience in process industries, as a socio-technical system, has four aspects of early detection, error-tolerant design, flexibility, and recoverability. Meanwhile, process industries' resilience has three phases: avoidance, survival, and recovery, determining the transition between normal state, process upset event, and catastrophic event. There may be various technical and social failures such as regulatory and human or organizational items that can lead to upset or catastrophic events. In the avoidance phase, the upset event is predicted, and thus, the system remains in a normal state. For the survival phase, the system state is assumed to be an upset process event, and the system tries to survive through the unhealthy process conditions or remains in the same state, probably with low performance. In the recovery phase, the system is supposed to be catastrophic, and the emergency barriers are prioritized to show the severity of the consequences and response time, leading to a resumption of a normal state. Therefore, a resilience-based network can be designed for process industries to show its inherent dynamic transition in nature. In this study, network data envelopment analysis (DEA), as a mathematical model, is used to evaluate the relative efficiency of the process industries regarding a network transition approach based on the system's internal structure. First, a resilience-based network is designed to consist of three states of normal, upset, and catastrophic events. Then, the efficiency of each industrial department, which is defined as decision-making units (DMUs), is evaluated using network DEA. As a case study, a refinery that is considered a critical process industry is assessed. Using the proposed model shows the efficient and inefficient DMUs in each of three states of normal, upset, and catastrophic events of the process and the projection onto efficient frontiers. Besides calculating the network efficiency, the performance of each state is extracted to precisely differentiate between DMUs. The results of this study, which is one of the fewest cases in the area of performance evaluation of process industries with a network approach, indicated a robust viewpoint for monitoring and assessment of risks.  相似文献   
80.
Objective: To reduce the severity of injuries and the number of cyclist deaths in traffic accidents, active safety devices providing cyclist detection are considered to be effective countermeasures. The features of car-to-bicycle collisions need to be known in detail to develop such safety devices.

Methods: The study investigated near-miss situations captured by drive recorders installed in passenger cars. Because similarities in the approach patterns between near-miss incidents and real-world fatal cyclist accidents in Japan were confirmed, we analyzed the 229 near-miss incident data via video capturing bicycles crossing the road in front of forward-moving cars. Using a video frame captured by a drive recorder, the time to collision (TTC) was calculated from the car's velocity and the distance between the car and bicycle at the moment when the bicycle initially appeared.

Results: The average TTC in the cases where bicycles emerged from behind obstructions was shorter than that in the cases where drivers had unobstructed views of the bicycles. In comparing the TTC of car-to-bicycle near-miss incidents to the previously obtained results of car-to-pedestrian near-miss incidents, it was determined that the average TTC in car-to-bicycle near-miss incidents was significantly longer than that in car-to-pedestrian near-miss incidents.

Conclusions: When considering the TTC in the test protocol of evaluation for safety performance of active safety devices, we propose individual TTCs for evaluation of cyclist and pedestrian detections, respectively. In the test protocols, the following 2 scenarios should be employed: bicycle emerging from behind an unobstructed view and bicycle emerging from behind obstructions.  相似文献   

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