Based on the maximum flux principle(MFP),a water quality evaluation model for surface water ecosystem is presented by using self-organization map(SOM) neural network simulation algorithm from the aspect of systematic ...Based on the maximum flux principle(MFP),a water quality evaluation model for surface water ecosystem is presented by using self-organization map(SOM) neural network simulation algorithm from the aspect of systematic structural evolution.This evaluation model is applied to the case of surface water ecosystem in Xindu District of Chengdu City in China.The values reflecting the water quality of five cross-sections of the system at different developing stages are obtained,with stable values of 1.438,2.952,1.86...展开更多
Migratory birds are considered natural reservoirs of avian influenza A viruses(AIVs).To further our viral ecology knowledge and understand the subsequent risk posed by wild birds,we conducted a 4-year surveillance stu...Migratory birds are considered natural reservoirs of avian influenza A viruses(AIVs).To further our viral ecology knowledge and understand the subsequent risk posed by wild birds,we conducted a 4-year surveillance study of AIVs in the bird wintering wetlands of the Yangtze River,China.We collected over8000 samples and isolated 122 AIV strains.Analyses were then carried out with 108 novel sequenced genomes and data were deposited in GISAID and other public databases.The results showed that the Yangtze River wintering wetlands functioned as a mixing ground,where various subtypes of AIVs were detected harboring a high diversity of nucleotide sequences;moreover,a portion of AIV gene segments were persistent inter-seasonally.Phylogenetic incongruence presented complex reassortment events and distinct patterns among various subtypes.In addition,we observed that viral gene segments in wintering wetlands were closely related to known North American isolates,indicating that intercontinental gene flow occurred.Notably,highly pathogenic H5 and low pathogenic H9 viruses,which usually circulate in poultry,were found to have crossed the poultry/wild bird interface,with the viruses introduced to wintering birds.Overall,this study represented the largest AIV surveillance effort of wild birds within the Yangtze River wintering wetlands.Surveillance data highlighted the important role of wintering wild birds in the ecology of AIVs and may enable future early warnings of novel AIV emergence.展开更多
基金Supported by National Water Science and Technology Research Project(No.2008ZX07102-001)
文摘Based on the maximum flux principle(MFP),a water quality evaluation model for surface water ecosystem is presented by using self-organization map(SOM) neural network simulation algorithm from the aspect of systematic structural evolution.This evaluation model is applied to the case of surface water ecosystem in Xindu District of Chengdu City in China.The values reflecting the water quality of five cross-sections of the system at different developing stages are obtained,with stable values of 1.438,2.952,1.86...
基金supported by the National Natural Science Foundation of China(81961138013,31570026,31970174,31970548,and 32061123001)the National Mega Project on Major Infectious Disease Prevention(2017ZX10103005-005)+1 种基金the Special Project of Ministry of Science and Technology(2013FY113500)the Russian Foundation for Basic Research—National Natural Science Foundation of China Collaboration Fund(19-54-55004)。
文摘Migratory birds are considered natural reservoirs of avian influenza A viruses(AIVs).To further our viral ecology knowledge and understand the subsequent risk posed by wild birds,we conducted a 4-year surveillance study of AIVs in the bird wintering wetlands of the Yangtze River,China.We collected over8000 samples and isolated 122 AIV strains.Analyses were then carried out with 108 novel sequenced genomes and data were deposited in GISAID and other public databases.The results showed that the Yangtze River wintering wetlands functioned as a mixing ground,where various subtypes of AIVs were detected harboring a high diversity of nucleotide sequences;moreover,a portion of AIV gene segments were persistent inter-seasonally.Phylogenetic incongruence presented complex reassortment events and distinct patterns among various subtypes.In addition,we observed that viral gene segments in wintering wetlands were closely related to known North American isolates,indicating that intercontinental gene flow occurred.Notably,highly pathogenic H5 and low pathogenic H9 viruses,which usually circulate in poultry,were found to have crossed the poultry/wild bird interface,with the viruses introduced to wintering birds.Overall,this study represented the largest AIV surveillance effort of wild birds within the Yangtze River wintering wetlands.Surveillance data highlighted the important role of wintering wild birds in the ecology of AIVs and may enable future early warnings of novel AIV emergence.
