碳普惠制是一种以城市居民为主体的温室气体自愿减排机制。将乘坐地铁出行作为低碳行为纳入碳普惠制,是建设全民参与型低碳社会的重要探索。本文提出了替代法和均值法两种市民乘坐地铁出行减碳量的核算方法,并以广州市为例,计算了2015...碳普惠制是一种以城市居民为主体的温室气体自愿减排机制。将乘坐地铁出行作为低碳行为纳入碳普惠制,是建设全民参与型低碳社会的重要探索。本文提出了替代法和均值法两种市民乘坐地铁出行减碳量的核算方法,并以广州市为例,计算了2015年广州市民乘坐地铁出行的减碳量。结果显示:替代法下广州市民乘坐地铁出行的减碳量约为0.5419 kg CO_2/人次,均值法下约为0.5155 kg CO_2/人次,如果按2015年广州市地铁系统的客运量计算,替代法和均值法下全市地铁系统的年减碳量分别约为130万t CO_2和124万t CO_2。其中,替代法主要参考已有的CCER方法学设计,具有一定的理论基础,但其替代出行模式的确定受被调查对象的主观影响较大,而均值法以城市现有的机动化出行模式为基准线,较少受到人为因素的干扰,均值法被认为更适合于计算碳普惠制下市民乘坐地铁出行的碳减排量。展开更多
作为现行碳排放权交易机制的延伸和有效补充,碳普惠制着眼于社会公众低碳行为减碳量的核算和交易。将公交车出行作为低碳行为纳入碳普惠制,是促进全民参与低碳社会建设的重要探索。文章借鉴CCER方法学并综合考虑交通数据的可获得性,提...作为现行碳排放权交易机制的延伸和有效补充,碳普惠制着眼于社会公众低碳行为减碳量的核算和交易。将公交车出行作为低碳行为纳入碳普惠制,是促进全民参与低碳社会建设的重要探索。文章借鉴CCER方法学并综合考虑交通数据的可获得性,提出了替代法和均值法两种居民公交车出行减碳量的核算方法,并以广州市为例,计算了2015年广州居民公交车出行的减碳量。结果显示,替代法核算广州居民公交车出行的减碳量为0.287 8 kg CO2/人次,均值法减碳量为0.351 4 kg CO2/人次,如果按2015年广州市公交车系统的客运量计算,替代法和均值法核算全市公交车系统的年减碳量分别约为750 000 t CO2和920000 t CO2。其中,替代法所需的替代出行模式受被调查对象的主观影响较大,而均值法以城市现有的机动化出行为基准线排放,受主观因素干扰较小,更适合核算居民公交车出行的碳减排量。展开更多
Methods for estimating synonymous and nonsynonymous substitution rates among protein-coding sequences adopt different mutation (substitution) models with subtle yet significant differences, which lead to different est...Methods for estimating synonymous and nonsynonymous substitution rates among protein-coding sequences adopt different mutation (substitution) models with subtle yet significant differences, which lead to different estimates of evolutionary information. Little attention has been devoted to the comparison of methods for obtaining reliable estimates since the amount of sequence variations within targeted datasets is always unpredictable. To our knowledge, there is little information available in literature about evaluation of these different methods. In this study, we compared six widely used methods and provided with evaluation results using simulated sequences. The results indicate that incorporating sequence features (such as transition/transversion bias and nucleotide/codon frequency bias) into methods could yield better performance. We recommend that conclusions related to or derived from Ka and Ks analyses should not be readily drawn only according to results from one method.展开更多
文摘碳普惠制是一种以城市居民为主体的温室气体自愿减排机制。将乘坐地铁出行作为低碳行为纳入碳普惠制,是建设全民参与型低碳社会的重要探索。本文提出了替代法和均值法两种市民乘坐地铁出行减碳量的核算方法,并以广州市为例,计算了2015年广州市民乘坐地铁出行的减碳量。结果显示:替代法下广州市民乘坐地铁出行的减碳量约为0.5419 kg CO_2/人次,均值法下约为0.5155 kg CO_2/人次,如果按2015年广州市地铁系统的客运量计算,替代法和均值法下全市地铁系统的年减碳量分别约为130万t CO_2和124万t CO_2。其中,替代法主要参考已有的CCER方法学设计,具有一定的理论基础,但其替代出行模式的确定受被调查对象的主观影响较大,而均值法以城市现有的机动化出行模式为基准线,较少受到人为因素的干扰,均值法被认为更适合于计算碳普惠制下市民乘坐地铁出行的碳减排量。
文摘作为现行碳排放权交易机制的延伸和有效补充,碳普惠制着眼于社会公众低碳行为减碳量的核算和交易。将公交车出行作为低碳行为纳入碳普惠制,是促进全民参与低碳社会建设的重要探索。文章借鉴CCER方法学并综合考虑交通数据的可获得性,提出了替代法和均值法两种居民公交车出行减碳量的核算方法,并以广州市为例,计算了2015年广州居民公交车出行的减碳量。结果显示,替代法核算广州居民公交车出行的减碳量为0.287 8 kg CO2/人次,均值法减碳量为0.351 4 kg CO2/人次,如果按2015年广州市公交车系统的客运量计算,替代法和均值法核算全市公交车系统的年减碳量分别约为750 000 t CO2和920000 t CO2。其中,替代法所需的替代出行模式受被调查对象的主观影响较大,而均值法以城市现有的机动化出行为基准线排放,受主观因素干扰较小,更适合核算居民公交车出行的碳减排量。
基金This work was supported by the Ministry of Science and Technology of China(Grant No.2001AA231061)the National Natural Science Foundation of China(Grant No.30270748)awarded to JY.We thank Mr.Jun Li for valuable discussion.
文摘Methods for estimating synonymous and nonsynonymous substitution rates among protein-coding sequences adopt different mutation (substitution) models with subtle yet significant differences, which lead to different estimates of evolutionary information. Little attention has been devoted to the comparison of methods for obtaining reliable estimates since the amount of sequence variations within targeted datasets is always unpredictable. To our knowledge, there is little information available in literature about evaluation of these different methods. In this study, we compared six widely used methods and provided with evaluation results using simulated sequences. The results indicate that incorporating sequence features (such as transition/transversion bias and nucleotide/codon frequency bias) into methods could yield better performance. We recommend that conclusions related to or derived from Ka and Ks analyses should not be readily drawn only according to results from one method.
