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881.
为探索西北部中等城市的城市热岛效应规律,利用2004—2010年天水市城、郊自动气象站资料,对天水市城、郊温度差异进行了系统分析。结果表明:天水市城区热岛效应比较显著;冬季是热岛现象最强的季节,夏季是热岛现象最弱的季节;城区热岛现象持续时间为18:00—10:00,占全天的2/3,最大强度达1.5℃;城区凉岛持续时间为11:00—17:00,占全天的1/3,最大强度为0.3℃;地面温度城、郊差比气温更大,40cm以下城区地温全年大于郊区;降雪日及连阴雨天气的中后期,城区基本上维持凉岛;强降温天气下,城、郊气温变化基本一致,差别不大。 相似文献
882.
锡林郭勒盟煤炭资源丰富,探明储量1448亿吨,仅次于鄂尔多斯市居全区第二。大规模资源开发引起地貌、土壤、植被、水文、空气质量的环境构成要素的破坏,正在以扬沙、空气污染等方式反作用于人类。加强矿山环境保护势在必行,只要我们坚持开发、保护和治理相结合,认真处理矿产资源开发与经济发展、生态环境保护三者之间关系,矿山生态环境就会大大改善,科学发展观也就会真正落到实处。 相似文献
883.
象山港海域N、P和CODMn的变化趋势及其与富营养化的关系 总被引:1,自引:0,他引:1
根据近20多年来(1984~2005)象山港海域海洋环境监测的基础资料,建立象山港海域CODMn、DIN和PO4-P的时间序列,用平均差值法、最小二乘法和自回归滑动平均法3种趋势分析方法,统计检验了该海域CODMn、DIN和的PO4-P的长期变化趋势。并用相关分析和影响因子分析方法,分析了CODMn、DIN和的PO4-P年际波动与富营养化的关系。结果表明:近20多年来象山港海域DIN和PO4-P的年平均浓度长期以来均呈增加的趋势,而CODMn呈降低的趋势;象山港海域富营养状态指数E长期以来一直呈降低的趋势,这与CODMn相同,与DIN和PO4-P的变化趋势相反。CODMn的变化与富营养状态指数E呈显著的正相关,DIN和PO4-P的变化与富营养化状态指数E呈弱的正相关;CODMn,DIN和PO4-P对富营养装态指数E的影响因子分别为6.9822,2.2449和3.3836,CODMn对富营养状态指数E年际变化的贡献程度远大于DIN和PO4-P。当CODMn含量变化幅度较大的时候,海水营养状态指数E的变化不能真实反映海域营养盐的含量变化特征,富营养状态指数E在表征海水富营养化程度时存在一定的局限性,这也揭示了中国第Ⅰ代海水富营养化评价体系存在的问题。 相似文献
884.
885.
Kenneth F.D. Hughey 《Journal of Cleaner Production》2011,19(5):532-541
Coordinated voluntary approaches to Pollution Prevention are widely practiced in many western-style economies. However, little empirical research has been undertaken into the extent to which these approaches match best practice pollution prevention approaches. In this paper nine programs employed by five regional and district councils in New Zealand are evaluated against nine ‘Best Practice’ design features. All five councils’ pollution prevention programs contained some of the best practice design features in their program’s design. Perhaps not surprisingly the older programs rank highest out of the five. However, all programs have the potential to develop towards containing all of the ‘best practice’ design features, with most emphasis needed on the credibility of program monitoring. From an ongoing research perspective, and also from an overall PP program performance point of view, the biggest challenge remains the extent and depth that the programs apply each of the design features. As presented they are extremely generic. While generic design features provide for flexibility in implementation, often seen as a positive, they can also be a recipe for ‘tokenism’, something that future researchers and program managers need to be aware of. We also sought to determine if these programs were contributing to sustainable management in New Zealand. Findings in this respect were equivocal. This finding in part is due to the lack of specificity around targets, monitoring and reporting, items needing further attention from managers and researchers. 相似文献
886.
Donald G. ChittockKenneth F.D. Hughey 《Journal of Cleaner Production》2011,19(5):542-551
Voluntary approaches to industry-wide pollution prevention programs have gained a global impetus. Despite this impetus relatively little research has been undertaken into identifying key features of successful programs. This research identified these features by reviewing selected programs in five countries, Australia, Canada, Japan, the United Kingdom and the United States. Nine key features have been identified, namely: Adequate and consistent funding; Collaborative relationship with industry; Single sector program focus; Setting credible goals; Info-regulation and resources available; Threat of credible enforcement; Regular and credible monitoring; Visible participant benefits; and, Transparent provision of program results. The research complements other work and while showing a high level of similarity in the features, provided also for the inclusion of two further design features, namely ‘adequate and consistent funding’, and developing a maintaining a ‘collaborative relationship with industry’. It is suggested that the nine design features alone, while important, are insufficient and that further research is required to identify these other supporting factors. 相似文献
887.
基于关联维的事故时间序列分形特征分析 总被引:4,自引:3,他引:1
根据我国"十五"期间事故统计数据,构造了一个事故时间序列;基于相空间重构理论,对事故序列进行了相空间重构,应用G-P算法,对事故时间序列的分形特征进行了研究,计算得出事故时间序列的关联维数。研究结果表明:当嵌入维数达到8以后,该事故动力学系统具有稳定的关联维数4.7,说明至少有5个因子在影响着事故时间序列的动态变化,并且该系统的有效自由度为8。本研究对建立事故时间序列的预测模型有较大的参考价值。 相似文献
888.
Host intra-clutch variation,cuckoo egg matching and egg rejection by great reed warblers 总被引:3,自引:1,他引:2
Prevailing theory predicts that lower levels of intra-clutch variation in host eggs facilitate the detection of brood parasitism.
We assessed egg matching using both human vision and UV-VIS spectrophotometry and then followed the nest fate of great reed
warblers naturally parasitised by European cuckoos. Rejection was predicted by the following three variables: matching between
cuckoo and host eggs on the main chromatic variable defined by principal components analysis of the egg spectra (which has
a strong loading in the UV); the number of host eggs in the nest; and human estimates of intra-clutch variation. The first
variable is not correlated to human estimates of matching, which do not predict rejection. In line with another recent study,
rejection rates were predicted by higher levels of intra-clutch variation in the host eggs, suggesting that higher rather
than lower levels of intra-clutch variation can facilitate the discrimination of cuckoo eggs by hosts. We suggest that the
importance of intra-clutch variation is context dependent, with intra-clutch variation being important when there is good
matching between the host and the cuckoo eggs. Our results also suggest that both spectrometric and human visual assessments
of egg matching and intra-clutch variation are prudent: the former provide the best method of estimating reflectance variation,
whereas the latter include some assessment of patterns of maculation. 相似文献
889.
Genetic variability among males is a necessary precondition for the evolution of female choice based on indirect genetic benefits.
In addition to mutations and host–parasite cycles, migration of locally adapted individuals offers an explanation for the
maintenance of genetic variability. In a previous study, conducting a reciprocal transplant experiment on a grasshopper, Chorthippus biguttulus, we found that environmental conditions significantly influenced not only body condition but also an important trait of male
calling song, the amplitude of song. Although not significant, all other analysed physical and courtship song traits and attractiveness
were superior in native than in transferred males. Thus, we concluded that local adaptation has a slight but consistent influence
on a range of traits in our study populations, including male acoustic attractiveness. In our present study, we scanned male
grasshoppers from the same two populations for amplification fragment length polymorphism (AFLP) loci connected with acoustic
attractiveness to conspecific females. We found greater differences in allele frequencies between the two populations, for
some loci, than are expected from a balance between drift and gene flow. These loci are potentially connected with locally
adapted traits. We examined whether these alleles show the proposed genotype environment interaction by having different associations
with attractiveness in the two populations. One locus was significantly related to sexual attractiveness; however, this was
independent of the males’ population affiliation. Future research on the evolution of female choice will benefit from knowledge
of the underlying genetic architecture of male traits under intraspecific sexual selection, and the ‘population genomics’
approach can be a powerful tool for revealing this structure. 相似文献
890.
Spatial and temporal variation of nitrogen exported by runo from
sandy agricultural soils 总被引:5,自引:0,他引:5
The eutrophication problem has drawn attention to nutrient leaching from agricultural soils, and an understanding of spatial and temporal variability is needed to develop decision-making tools. Thus, eleven sites were selected to monitor, over a two-year period, spatial and temporal variation of runoff discharge and various forms of N in surface runoff in sandy agricultural soils. Factors influencing the variation of runoff discharge and various forms of N in surface runoff were analyzed. Variation of annual rainfall was small among 11 sites, especially between 2001 and 2002. However, variation of annual discharge was significant among the sites. The results suggest that rainfall patterns and land use had significant effect on discharge. The concentrations of total N, total kjeldahl N (TKN), organic matter-associated N (OM-N), NO3- -N, and NHn+-N in the runoff ranged widely from 0.25 to 54.1, 0.15 to 20.3, 0.00 to 14.6, 0.00 to 45.3, and 0.00 to 19.7 mg/L, respectively. Spatial and temporal variations in the N concentration and runoff discharge were noted among the different sites. Annual loads of N in the runoff varied widely among monitoring sites and depend mainly on runoff discharge. High loads of total N, OM-N, NO3--N, and NHn+-N in the runoff either in citrus groves or on vegetable farms occurred from June to October for each year, which coincided with the rainy season in the region. This study found that N in surface runoff was related to rainfall intensity, soil N level, and fertilizer use. 相似文献