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A WRF-CMAQ modeling system is used to assess the impact of emission control strategies and weather conditions on haze pollution in Zhongshan, Guangdong Province, China. One-month simulations for January 2014 are completed and evaluated with the observational data. The simulations show reasonable agreement with the observations. Several sensitivity studies are completed to quantify the percentage contributions of local emissions versus regional emissions to the PM2.5 concentrations under different weather conditions. The results indicate that the contributions from local emission is higher than those of the emissions from regional transport when there is no intrusion of cold front (i.e., 58% contribution from local emission versus 42% contribution from the regional transport). The contribution of regional transport is increased to 76% when a strong cold front appears. Furthermore, the sensitivity study demonstrates that PM2.5 concentrations on the first, second, and third days are reduced by 47%, 52%, and 58%, respectively, after the local emissions are turned off when there is no intrusion of cold front. Finally, a case study shows that industrial, residential, and mobile emissions account for 24%, 22%, and 15% of the change of PM2.5, respectively, during a heavy haze pollution event in Zhongshan. [ABSTRACT FROM AUTHOR]

Precise genetic mutation of model animals is highly valuable for functional investigation of human mutations. Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9)- induced homology-directed repair (HDR) is usually used for precise genetic mutation, being limited by the relatively low efficiency compared with that of non-homologous end joining (NHEJ). Although inhibition of NHEJ was shown to enhance HDR-derived mutation, in this work, without inhibition of NHEJ, we first generated gene-modified pigs harboring precise orthologous human mutation (Sox10 c.A325>T) via CRISPR/Cas9-induced HDR in zygotes using single-strand oligo DNA (ssODN) as template with an efficiency as high as 80%, indicating that pig zygotes exhibited high activities of HDR relative to NHEJ and were highly amendable to genetic mutation via CIRSPR/Cas9- induced HDR. Besides, we found a higher concentration of ssODN remarkably reduced HDR-derived mutation in pig zygotes, suggesting a possible balance for optimal HDR-derived mutation in zygotes between the excessive accessibility to HDR templates and the activities of HDR relative to NHEJ which appeared to be negatively correlated to ssODN concentration. In addition, the HDR-derived mutation, as well as those from NHEJ, extensively integrated into various tissues including gonad of founder pig without detected off-targeting, suggesting CRISPR/Cas9-induced HDR in zygotes is a reliable approach for precise genetic mutation in pigs. [ABSTRACT FROM AUTHOR]