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Among the G20 countries, China is the only country to experience an increase in electricity generation from coal-fired thermal power plants from 2019 to 2020. This study aims to develop an analytical framework combining metafrontier data envelopment analysis with the logarithmic mean Divisia index for a detailed decomposition analysis of 'mass-based' energy-related CO2 reduction potential through efficiency improvements in coal-fired thermal power plants in China. The results show that inefficiency in power generation can be largely attributed to differences in the location of power plants and the production scale. Moreover, the impact of regional heterogeneity on the changes in power generation efficiency is more notable for the small–medium power plants in the northeast region than the large power plants in the western region in China. However, when focusing on the mass-based CO2 reduction potential associated with the regional heterogeneity, its positive effects in the western region for the large power plants are 6.2 times larger than that in the northeast region for the small–medium power plants. These results imply that an analysis that focuses only on the efficiency score would ignore the production scale of coal-fired thermal power plants and thus would fail to properly evaluate the environmental impacts associated with efficiency changes. [ABSTRACT FROM AUTHOR]

The industrially important yeast Candida utilis is widely used in production of food and medical materials, but its host-vector system has not been well developed. We screened for compact and efficient ARSs to construct practically useful vectors. The C. utilis strain AHU3053 was found to be efficiently transformed by the conventional lithium acetate method and was used as the host. The C. utilis IAM4264 genomic library was constructed by inserting the partial Sau3AI digests in pRI51, which has a kanMX gene expressible in C. utilis. By examining 98 C. utilis G418-resistant transformants, five plasmids had the highest ARS activity. By trimming of the inserts, the 1490 and 552 bp fragments with transformation activity of over 103/µg DNA were obtained from ARS3 and ARS4, respectively. Although several sequences identical to S. cerevisiae ARS consensus sequences (ACSs) were found in ARS3 and ARS4, our deletion analysis indicated that these were not essential for the activity. Because the minimal functional ARS fragment was also several-fold larger than that of S. cerevisiae, the C. utilis ARSs have some unique characteristics resembling the Sz. pombe ARSs. These ARSs were functional in other C. utilis strains tested and useful for constructing practical vectors. The DNA sequences have been deposited with the DDBJ/EMBL/GenBank database under Accession Nos AB206824 and AB206825. Copyright © 2005 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]