Eleven acid mine drainage （AMD） samples were obtained from southeast of China for the analysis of the microbial communities diversity, and the relationship with geochemical variables and spatial distance by using a ...Eleven acid mine drainage （AMD） samples were obtained from southeast of China for the analysis of the microbial communities diversity, and the relationship with geochemical variables and spatial distance by using a culture-independent 16S rDNA gene phylogenetic analysis approach and multivariate analysis respectively. The principle component analysis （PCA） of geochemical variables shows that eleven AMDs can be clustered into two groups, relative high and low metal rich （RHMR and RLMR） AMDs. Total 1691 clone sequences are obtained and the detrended correspondence analysis （DCA） of operational taxonomic units （OTUs） shows that, ~,-Proteobacteria, Acidobacteria, Actinobacteria, Cyanobacteria, Firmicutes and Nitrospirae are dominant species in RHMR AMDs. In contrast, a-Proteobacteria, fl-Proteobacteria, Planctomycetes and Bacteriodetes are dominant species in RLMR AMD. Results also show that high-abundance putative iron-oxidizing and only putative sulfur-oxidizing microorganisms are found in RHMR AMD. Multivariate analysis shows that both geochemical variables （r=0.429 3, P=-0.037 7） and spatial distance （r=0.321 3, P=-0.018 1） are significantly positively correlated with microbial community and pH, Mg, Fe, S, Cu and Ca are key geochemistry factors in shaping microbial community. Variance partitioning analysis shows that geochemical variables and spatial distance can explain most （92%） of the variation.展开更多
Among all the emission reduction measures,carbon tax is recognized as the most effective way to protect our climate.That is why the Chinese government has recently taken it as a tax reform direction.In the current eco...Among all the emission reduction measures,carbon tax is recognized as the most effective way to protect our climate.That is why the Chinese government has recently taken it as a tax reform direction.In the current economic analysis,the design of carbon tax is mostly based on the target to maximize the efficiency.However,based on the theory of tax system optimization,we should also consider other policy objectives,such as equity,revenue and cost,and then balance different objectives to achieve the suboptimum reform of carbon tax system in China.展开更多
This paper investigates the marginal abatement cost （MAC） of CO： emissions across 104 Chinese cities between 2001 and 2008. Based on parametric directional distance function, this paper discovers that the mean marg...This paper investigates the marginal abatement cost （MAC） of CO： emissions across 104 Chinese cities between 2001 and 2008. Based on parametric directional distance function, this paper discovers that the mean marginal abatement cost of CO2 emissions for sample cities was 967 yuan/ton. In terms of region, CO： marginal abatement cost is significantly higher in China＇s eastern region than in central and western regions; in terms of provincial-level region, it is the highest in Shanghai and the lowest in Shaanxi in terms of city, it is the highest in Shanghai and the lowest in Zhangjiajie with the ratio between their medians being at 48：1; in terms of time, marginal abatement cost has been always on the rise with significant intercity disparities. There is a U-shaped curve relationship between marginal abatement cost of cities and CO2 emissions per unit of GDP, which is negatively correlated with the share of secondary industry and positively correlated with the level of urbanization.展开更多
基金Project(2010CB630901) supported by the National Basic Research Program of ChinaProject(50621063) supported by Creative Research Group of China+2 种基金Projects(51104189, 50321402, 50774102) supported by the National Natural Science Foundation of ChinaProject (1343-77341) supported by the Graduate Education Innovative Program of Central South University, ChinaProject(DOE-ER64125) supported by the Department of Energy, Office of Science under the Environmental Remediation Science Program of USA
文摘Eleven acid mine drainage （AMD） samples were obtained from southeast of China for the analysis of the microbial communities diversity, and the relationship with geochemical variables and spatial distance by using a culture-independent 16S rDNA gene phylogenetic analysis approach and multivariate analysis respectively. The principle component analysis （PCA） of geochemical variables shows that eleven AMDs can be clustered into two groups, relative high and low metal rich （RHMR and RLMR） AMDs. Total 1691 clone sequences are obtained and the detrended correspondence analysis （DCA） of operational taxonomic units （OTUs） shows that, ~,-Proteobacteria, Acidobacteria, Actinobacteria, Cyanobacteria, Firmicutes and Nitrospirae are dominant species in RHMR AMDs. In contrast, a-Proteobacteria, fl-Proteobacteria, Planctomycetes and Bacteriodetes are dominant species in RLMR AMD. Results also show that high-abundance putative iron-oxidizing and only putative sulfur-oxidizing microorganisms are found in RHMR AMD. Multivariate analysis shows that both geochemical variables （r=0.429 3, P=-0.037 7） and spatial distance （r=0.321 3, P=-0.018 1） are significantly positively correlated with microbial community and pH, Mg, Fe, S, Cu and Ca are key geochemistry factors in shaping microbial community. Variance partitioning analysis shows that geochemical variables and spatial distance can explain most （92%） of the variation.
文摘Among all the emission reduction measures,carbon tax is recognized as the most effective way to protect our climate.That is why the Chinese government has recently taken it as a tax reform direction.In the current economic analysis,the design of carbon tax is mostly based on the target to maximize the efficiency.However,based on the theory of tax system optimization,we should also consider other policy objectives,such as equity,revenue and cost,and then balance different objectives to achieve the suboptimum reform of carbon tax system in China.
基金supported by the National Natural Sciences Foundation(Approval No.41201582)Beijing Natural Sciences Foundation(9152011)+1 种基金Mingde Scholars Program of Renmin University of China(Approval No.13XNJ016)Peking University-Lincoln Institute Center for Urban Development and Land Policy
文摘This paper investigates the marginal abatement cost （MAC） of CO： emissions across 104 Chinese cities between 2001 and 2008. Based on parametric directional distance function, this paper discovers that the mean marginal abatement cost of CO2 emissions for sample cities was 967 yuan/ton. In terms of region, CO： marginal abatement cost is significantly higher in China＇s eastern region than in central and western regions; in terms of provincial-level region, it is the highest in Shanghai and the lowest in Shaanxi in terms of city, it is the highest in Shanghai and the lowest in Zhangjiajie with the ratio between their medians being at 48：1; in terms of time, marginal abatement cost has been always on the rise with significant intercity disparities. There is a U-shaped curve relationship between marginal abatement cost of cities and CO2 emissions per unit of GDP, which is negatively correlated with the share of secondary industry and positively correlated with the level of urbanization.
