Let L=-div（A▽） be a second-order divergent-form elliptic operator,where A is an accretive n×n matrix with bounded and measurable complex coefficients on Herein,we prove that the commutator [b,L1/2]of the Kato ...Let L=-div（A▽） be a second-order divergent-form elliptic operator,where A is an accretive n×n matrix with bounded and measurable complex coefficients on Herein,we prove that the commutator [b,L1/2]of the Kato square root L1/2 and b with ▽b∈Ln（Rn）（n> 2）,is bounded from the homogenous Sobolev space L1p（Rn） to Lp（Rn）（p-（L） <p<p+（L））.展开更多
The mismatch distribution is a good descriptive summary statistic that describes the phenomena of population genetics. This article scanned mismatch distribution on human genome with single nucleotide polymorphism （...The mismatch distribution is a good descriptive summary statistic that describes the phenomena of population genetics. This article scanned mismatch distribution on human genome with single nucleotide polymorphism （SNP） data from the International HapMap Project. It is found that the abnormal mismatch distribution could imply some special segments on some chromosomes. One of the segments, on chromosome 8, was proved as an inversion. Other special segments may also imply some special structure on chromo- somes, such as duplication. The conjectures of other segments still need further research.展开更多
Daya Bay is a semi-enclosed bay in the South China Sea which is a coastal ecosystem with significant ecological and economic value that is subjected to a variety of anthropogenic disturbances.However,long-term variati...Daya Bay is a semi-enclosed bay in the South China Sea which is a coastal ecosystem with significant ecological and economic value that is subjected to a variety of anthropogenic disturbances.However,long-term variation in fish community structure in this Bay remains uncertain.In this study,we aimed to explore the changing characteristics of fish species composition and community structure in Daya Bay during the past 30 years using data from 1989 to 2021 from bottom trawl surveys and historical literature data.As of now,a total of 544 species of fish have been identified in the Bay,belonging to 24 orders and 125 families.The structure of the fish community in the bay has changed over time.Firstly,there has been a clear decrease in the number of species and biomass of large fish.Secondly,the number of fish constituent orders and families has decreased.Moreover,both the average taxonomic distinctness and variation in taxonomic distinctness decreased from 1989 to 2021.Thirdly,there is low similarity among fishes at different time phases and distinct changes in the composition of dominant species.Present results indicate that the fish community structure in Daya Bay has tended to reflect a decline in diversity,shifts in composition,and shrinking of fish body size in the past 30 years.This study improves our understanding of fish species composition and its drivers over time in Daya Bay,providing important knowledge to support the protection and restoration of this ecosystem and the important ecosystem services it provides.展开更多
基金supported by National Natural Science Foundation of China (Grant No. 11471033)Program for New Century Excellent Talents in University of China (Grant No. NCET-11-0574)+1 种基金the Fundamental Research Funds for the Central Universities (Grant No. FRF-BR-17-001B)the Fundamental Research Funds for Doctoral Candidate of University of Science and Technology Beijing (Grant No. FRF-BR-17018)
文摘Let L=-div（A▽） be a second-order divergent-form elliptic operator,where A is an accretive n×n matrix with bounded and measurable complex coefficients on Herein,we prove that the commutator [b,L1/2]of the Kato square root L1/2 and b with ▽b∈Ln（Rn）（n> 2）,is bounded from the homogenous Sobolev space L1p（Rn） to Lp（Rn）（p-（L） <p<p+（L））.
文摘The mismatch distribution is a good descriptive summary statistic that describes the phenomena of population genetics. This article scanned mismatch distribution on human genome with single nucleotide polymorphism （SNP） data from the International HapMap Project. It is found that the abnormal mismatch distribution could imply some special segments on some chromosomes. One of the segments, on chromosome 8, was proved as an inversion. Other special segments may also imply some special structure on chromo- somes, such as duplication. The conjectures of other segments still need further research.
基金funded by Fundamental and Applied Fundamental Research Major Program of Guangdong Province(2019B030302004-05)Science and Technology Planning Project of Guangdong Province(2019B121201001)+2 种基金Central Public-interest Scientific Institution Basal Research Fund,CAFS(2023TD16)Central Public-interest Scientific Institution Basal Research Fund,South China Sea Fisheries Research Institute,CAFS(2021SD04 and 2019TS28)Financial Fund of the Ministry of Agriculture and Rural Affairs,P.R.of China(NFZX2021).
文摘Daya Bay is a semi-enclosed bay in the South China Sea which is a coastal ecosystem with significant ecological and economic value that is subjected to a variety of anthropogenic disturbances.However,long-term variation in fish community structure in this Bay remains uncertain.In this study,we aimed to explore the changing characteristics of fish species composition and community structure in Daya Bay during the past 30 years using data from 1989 to 2021 from bottom trawl surveys and historical literature data.As of now,a total of 544 species of fish have been identified in the Bay,belonging to 24 orders and 125 families.The structure of the fish community in the bay has changed over time.Firstly,there has been a clear decrease in the number of species and biomass of large fish.Secondly,the number of fish constituent orders and families has decreased.Moreover,both the average taxonomic distinctness and variation in taxonomic distinctness decreased from 1989 to 2021.Thirdly,there is low similarity among fishes at different time phases and distinct changes in the composition of dominant species.Present results indicate that the fish community structure in Daya Bay has tended to reflect a decline in diversity,shifts in composition,and shrinking of fish body size in the past 30 years.This study improves our understanding of fish species composition and its drivers over time in Daya Bay,providing important knowledge to support the protection and restoration of this ecosystem and the important ecosystem services it provides.
