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161.
162.
Oxidative stress (OS) and fluctuating asymmetry (FA) as risk markers for environmental stress are widely used to predict changes in the health and fitness of many animals exposed to pollutants. However, from the perspective of protecting declining amphibians, it remains to be verified which one would be a reliable indicator for amphibians exposed to long-term heavy metal pollution under natural conditions. In this study, the OS and FA of Bufo raddei exposed to natural heavy metal pollution were analyzed to determine which marker is more accurate for indicating heavy metal-induced stress. Three years of data were collected during the breeding season of B. raddei from Baiyin (BY), which has been mainly contaminated with Cu, Zn, Pb, and Cd compounds for a long period, and from Liujiaxia (LJX), which is a relatively unpolluted area. Unexpectedly, although significant accumulation of the four heavy metals was found in the kidney and liver of B. raddei from BY, the levels of superoxide dismutase, glutathione peroxidase, and malondialdehyde in these two organs were found to be irregular, with low repeatability in both BY and LJX. However, significant differences in the levels of FA were observed in B. raddei populations from these two areas over the past 3 years (P < 0.01). The degrees of FA in B. raddei populations from BY and LJX were assessed as degree 4 and 1, respectively. In short, this study suggested that FA was a more reliable and effective indicator than OS to monitor and predict long-term environmental stress on anuran amphibians.  相似文献   
163.
Polybrominated diphenyl ethers (PBDEs), organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) in 25 surface sediments in three cities (Nantong, Wuxi, and Suzhou) in the Yangtze River Delta, eastern China were measured. The mean concentrations were 378, 45.8, 1.98, 4,002 ng/g for PBDEs, OCPs, PCBs, and PAHs, respectively. Their levels in the sediments in the three cities were generally consistent with the city industrialization. PBDEs and OCPs were markedly dominated by deca-BDE (>90 %) and DDTs (>70 %). A principle component analysis of the analytes identified three major factors suggesting different sources of the contaminants in the sediments. PBDEs and the organic carbon in the sediments have common sources from industrial activities; whereas OCPs and PCBs, correlated with the second factor, were mainly from historical sources. The third factor with loadings of PAHs is indicative of various combustion sources. Ecological risk assessment indicated that the potential highest risk is from DDTs, for which 22 sites exceed the effects range low (ERL) values and three sites exceed the effects range median (ERM) value.  相似文献   
164.
Along with the progressive acceleration of urbanization, the need to identify potentially troublesome “Not In My Back Yard” (NIMBY) facilities in the city is inevitable. To resolve NIMBY conflict, it is important to know people’s NIMBY risk acceptability for these facilities. A questionnaire survey was used among Chinese and Japanese college students to identify NIMBY risk acceptability. LISREL was used to construct a structural equation model to analyze the difference in NIMBY risk acceptability between the Chinese and Japanese college students. Factors that may affect NIMBY risk acceptability were analyzed: “perceiving utility,” “perceiving risk,” “trust in government,” “reasonable compensation,” and “procedural justice.” The findings show that Japanese students’ concerns were greater than Chinese students’ concerns. Perceiving utility and perceiving risk were the most important factors that affect people’s NIMBY risk acceptability, followed by procedural justice, trust in government, and reasonable compensation. There is a difference between the different cultural backgrounds in confronting the risk: Chinese students focus more on the reputation and value of real estate, while Japanese students pay more attention to environmental pollution and damage to health. Furthermore, cultural influences play a role in students’ risk perception. To improve the risk acceptability for NIMBY facilities and provide a basis for resolving NIMBY conflicts, it is necessary to ensure the benefits of the NIMBY facility while reducing environmental pollution. The findings of this study may be of interest for policy makers and practitioners to devise future NIMBY strategies.  相似文献   
165.
A large area of plantations has been established worldwide and especially in China. Evaluating the restoration status of these plantations is essential for their long-term management. Based on our previous work, we used an ecological memory (EM) approach to evaluate four 26-year-old plantations that represent four common kinds of plantations in subtropical China, i.e., mixed broad-leaved plantation (MBP), mixed coniferous plantation (MCP), eucalyptus plantation (EP), and mixed legume plantation (MLP). Comparing them with the regional climax community, i.e., monsoon evergreen broad-leaved forest (BF), all four plantations accumulated nearly the same pattern of EM during succession. EM was >50 % for soil minerals, light conditions, soil age, soil animals, and soil microbes. EM was about 25 % for soil pollen and 10 % for birds, soil seed bank, and plant species. The total EM value of the four plantations ranged from 50.96 to 52.54, which indicated that all four plantations were in the regional, natural trajectory of succession and between the early and medium successional stages. The results indicated that natural succession processes are unlikely to be accelerated by planting late-stage tree species without sufficient EM. The results also demonstrated that all four plantations were in positive successional trajectories, and the positive succession dynamics were greater in the MLP and MCP. We suggest that the entire natural succession trajectory be used to evaluate the restoration of a site and that the ultimate restoration target be divided into several milestones along the reference trajectory to monitor progress. Forest restoration may be accelerated by starting with a minimum dynamic unit supporting sufficient EM.  相似文献   
166.
To predict the coherence in local responses to large-scale climatic forcing among aquatic systems, we developed a generalized approach to compare long-term data of dimictic water bodies based on phenomenologically defined hydrographic events. These climate-sensitive phases (inverse stratification, spring overturn, early thermal stratification, summer stagnation) were classified in a dual code (cold/warm) based on threshold temperatures. Accounting for a latitudinal gradient in seasonal timing of phases derived from gradients in cumulative irradiation (2.2?days per degree latitude), we found a high spatial and temporal coherence in warm–cold patterns for six lakes (84?%) and the Baltic Sea (78?%), even when using the same thresholds for all sites. Similarity to CW-codes for the North Sea still was up to 72?%. The approach allows prediction of phase-specific warming trends and resulting instantaneous or time-delayed ecological responses. Exemplarily, we show that warming during early thermal stratification controls food-web-mediated effects on key species during summer.  相似文献   
167.
本文分析了衡阳地区地表水资源特征和地下水资源类型与特征,并根据工农业生产的发展,需水与供水间的矛盾及旱涝灾害等情况,对水资源的开发利用途径进行了探讨。  相似文献   
168.
本文以镇江市消防地图及其相关信息为对象,分析了消防信息的特点和现有的输入方法,以及作者在设计与建造镇江市消防信息数据库的实践中采用的技术路线和具体方法。  相似文献   
169.
静电除尘在烧结机头烟尘治理中的应用   总被引:4,自引:0,他引:4  
通过对安钢烧结机一、二期工程中烧结机头电除尘器结构性能和运行效果对比,结合安钢实际运行情况,分析了一期工程中电除尘器的运行存在的问题,重点对电除尘器的结构特点进行阐述,以提供一种适用于烧结机头烟尘治理的电除尘技术。  相似文献   
170.
南水北调中线工程对汉江中下游工业发展的影响   总被引:14,自引:3,他引:11  
南水北调中线工程计划从丹江口水库向我国北方每年调水145亿m^3,汉江丹江口以下地区的水资源量将随之相应减少。汉江中下游地区是湖北省盐化工、机械、石油、食品、化肥、电力的重要生产地区,是湖北省的汽车工业走廊,其经济在湖北省占有举足轻重的地位。由于经济的迅速发展,下世纪工农业生产和人民生活对水资源的需求将从现在的140亿m^3增加到250亿m^3以上,需水量将达到水资源量的58%,潜伏着严重的水资源  相似文献   
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