Molecular investigations have raised concerns about the ecological risks of green tides caused by alien Ulva species in new habitats.The green tide-forming species U.californica Wille was generally considered to be na...Molecular investigations have raised concerns about the ecological risks of green tides caused by alien Ulva species in new habitats.The green tide-forming species U.californica Wille was generally considered to be native to North America,but new records have been widely reported in Europe,Asia,and Oceania in recent decades,indicating a strong dispersal capacity of the species.In this study,the first record of U.californica on the coastline of China's Mainland was reported,following a combined identification with multi-molecular markers and morphological characterization.It was shown that this species has a discontinuous distribution pattern along the coast of China's Mainland,with northern populations in the Yellow Sea and southern populations in the East China Sea and South China Sea.According to results of examination for life cycles and identification with mating type(MT)genetic markers,it was indicated that all U.californica samples were male gametophytes,and reproduced themselves through parthenogenesis solely.Combined with the fact that southern and northern populations are highly genetically identical,here we believed that U.californica was a recent alien species to China's Mainland with a rapid local spread.This finding provided evidences that the ability to reproduce in a variety of ways may play an important role in the spread of Ulva species,as well as essential basic data for marine risk management of green tides in China.In addition,according to the phylogeographic analysis,the possible geographical origin and global dispersal routes of U.californica were also proposed.展开更多
This paper provides a comparative study of housing policies in the greater China area and Singapore.We trace out the key features of the housing markets in the Chinese mainland,the Hong Kong SAR,the Macao SAR,and Sin...This paper provides a comparative study of housing policies in the greater China area and Singapore.We trace out the key features of the housing markets in the Chinese mainland,the Hong Kong SAR,the Macao SAR,and Singapore and review policies adopted in these markets.Soaring housing prices may distort capital allocation efficiency as money flows into housing market instead of more productive sectors,which poses threat to longterm sustainability and economic growth.Governments in these four jurisdictions have implemented various macroprudential policies and regulations in an attempt to curb housing demand,however the effectiveness of housing policies varies across markets.The housing prices stabilise in Singapore but continue to rise in Greater China despite the introductions of various tightening policies.The policy effectiveness is contingent on not only the characteristics of the market but also on its design and implementations.展开更多
基金Supported by the Science&Technology Basic Resources Investigation Program of China(No.2018FY100205)the National Natural Science Foundation of China(No.41776153)+3 种基金the Key Deployment Project of Centre for Ocean Mega-Research of ScienceChinese Academy of Science(No.COMS2019Q05)the Key R&D Program of Shandong Province(No.2019GSF107012)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA23050302)。
文摘Molecular investigations have raised concerns about the ecological risks of green tides caused by alien Ulva species in new habitats.The green tide-forming species U.californica Wille was generally considered to be native to North America,but new records have been widely reported in Europe,Asia,and Oceania in recent decades,indicating a strong dispersal capacity of the species.In this study,the first record of U.californica on the coastline of China's Mainland was reported,following a combined identification with multi-molecular markers and morphological characterization.It was shown that this species has a discontinuous distribution pattern along the coast of China's Mainland,with northern populations in the Yellow Sea and southern populations in the East China Sea and South China Sea.According to results of examination for life cycles and identification with mating type(MT)genetic markers,it was indicated that all U.californica samples were male gametophytes,and reproduced themselves through parthenogenesis solely.Combined with the fact that southern and northern populations are highly genetically identical,here we believed that U.californica was a recent alien species to China's Mainland with a rapid local spread.This finding provided evidences that the ability to reproduce in a variety of ways may play an important role in the spread of Ulva species,as well as essential basic data for marine risk management of green tides in China.In addition,according to the phylogeographic analysis,the possible geographical origin and global dispersal routes of U.californica were also proposed.
文摘This paper provides a comparative study of housing policies in the greater China area and Singapore.We trace out the key features of the housing markets in the Chinese mainland,the Hong Kong SAR,the Macao SAR,and Singapore and review policies adopted in these markets.Soaring housing prices may distort capital allocation efficiency as money flows into housing market instead of more productive sectors,which poses threat to longterm sustainability and economic growth.Governments in these four jurisdictions have implemented various macroprudential policies and regulations in an attempt to curb housing demand,however the effectiveness of housing policies varies across markets.The housing prices stabilise in Singapore but continue to rise in Greater China despite the introductions of various tightening policies.The policy effectiveness is contingent on not only the characteristics of the market but also on its design and implementations.
