[Objective] The study was to analyze the phylogenesis of Anas platyrhynchos. [Method] Complete sequence of mitochondrial ND2 gene of 4 Anas platyrhynchos was determined by direct DNA sequencing based on PCR products. ...[Objective] The study was to analyze the phylogenesis of Anas platyrhynchos. [Method] Complete sequence of mitochondrial ND2 gene of 4 Anas platyrhynchos was determined by direct DNA sequencing based on PCR products. Combined with ND2 gene sequences of the Anas Linnaeus accessed in GenBank, phylogenetic tree was constructed by Neighbor-joining and maximum parsimony methods. [Result] The ND2 gene sequences of 4 Anas platyrhynchos were identical(1 041 bp in length; the nucleotide contents of A, G, T, and C were 28.91%, 13.35%, 20.75% and 36.98% respectively; A+T content approximated to that of C+G). Sequences of ND2 gene of mallard were same as spotbill duck, and had high homology with others. The phylogenetic trees indicated mallard and spotbilled duck were close in genetic relationship, both shared a haplotype; then Philippine duck, green-winged teal and northern pintail fell into branch ''A". [Conclusion] The domestic duck may be domesticated from mallard and spotbilled duck.展开更多
[Objective] The aim was to analyze the reasons resulting in the brittleness of Anas crecca crecca.[Method]The structure of the eggshell crushed in hatching process was scanned and its basic elements were analyzed by u...[Objective] The aim was to analyze the reasons resulting in the brittleness of Anas crecca crecca.[Method]The structure of the eggshell crushed in hatching process was scanned and its basic elements were analyzed by using electron microscope and Energy Disperse Spectroscopy.[Result]The basic structures of Anas crecca crecca eggs were the same;however,there was great possibility that one of the main reasons affecting hatch ability was the cracks in the outside surface of eff shell.[Conclusion]This study would provide a theoretical basis for the research on artificial in cubation and the egg structure of Anas crecca crecca.展开更多
Understanding migratory waterfowl spatiotemporal distributions is important because,in addition to their economic and cultural value,wild waterfowl can be infectious reservoirs of highly pathogenic avian influenza vir...Understanding migratory waterfowl spatiotemporal distributions is important because,in addition to their economic and cultural value,wild waterfowl can be infectious reservoirs of highly pathogenic avian influenza virus(HPAIV).Waterfowl migration has been implicated in regional and intercontinental HPAIV dispersal,and predictive capabilities of where and when HPAIV may be introduced to susceptible spillover hosts would facilitate biosecurity and mitigation efforts.To develop forecasts for HPAIV dispersal,an improved understanding of how individual birds interact with their environment and move on a landscape scale is required.Using an agent-based modeling approach,we integrated individual-scale energetics,species-specific morphology and behavior,and landscape-scale weather and habitat data in a mechanistic stochastic framework to simulate Mallard(Anas platyrhynchos)and Northern Pintail(Anas acuta)annual migration across the Northern Hemisphere.Our model recreated biologically realistic migratory patterns using a first principles approach to waterfowl ecology,behavior,and physiology.Conducting a limited structural sensitivity analysis comparing reduced models to eBird Status and Trends in reference to the full model,we identified density dependence as the main factor influencing spring migration and breeding distributions,and wind as the main factor influencing fall migration and overwintering distributions.We show evidence of weather patterns in Northeast Asia causing significant intercontinental pintail migration to North America.By linking individual energetics to landscapescale processes,we identify key drivers of waterfowl migration while developing a predictive model responsive to daily weather patterns.This model paves the way for future waterfowl migration research predicting HPAIV transmission,climate change impacts,and oil spill effects.展开更多
本文在ANA序列下,利用Rosenthal不等式,研究边缘频率插值密度估计的一致强相合性,并在适当的条件下得到其收敛速度,拓展了已有文献的研究。为验证结论的有效性,使用R软件进行数值模拟。模拟结果显示,随着样本量的增大,边缘频率插值密度...本文在ANA序列下,利用Rosenthal不等式,研究边缘频率插值密度估计的一致强相合性,并在适当的条件下得到其收敛速度,拓展了已有文献的研究。为验证结论的有效性,使用R软件进行数值模拟。模拟结果显示,随着样本量的增大,边缘频率插值密度估计值逐渐趋于真实密度。In this paper, we study the uniform strong consistency and its rate of the density estimation of edge frequency polygons under asymptotically negatively associated (ANA) sequences using Rosenthal-type inequality, which extends the existing studies in the literature. To validate the theoretical conclusions, we conduct numerical simulations in R software. The results demonstrate that the proposed density estimator converges uniformly to the true density as the sample size increases.展开更多
A series of 14 destructive wildfires swept across the US West Coast,particularly Southern California,from January 7 to 31,2025.The fires were exacerbated by drought conditions,low humidity,accumulated vegetation from ...A series of 14 destructive wildfires swept across the US West Coast,particularly Southern California,from January 7 to 31,2025.The fires were exacerbated by drought conditions,low humidity,accumulated vegetation from the previous winter,and hurricane-force Santa Ana winds,which in some areas reached speeds of 45 m/s.The wildfires claimed at least 30 lives,forced over 200,000 people to evacuate,destroyed more than 18,000 homes and structures,and burned approximately 233 km^(2)of land in total(Wikipedia,2025).展开更多
基金Supported by National Key Technology R&D program(2006BAD06B06)National Infrastructure of Natural Resources for Science and Technology(2004DKA30460)~~
文摘[Objective] The study was to analyze the phylogenesis of Anas platyrhynchos. [Method] Complete sequence of mitochondrial ND2 gene of 4 Anas platyrhynchos was determined by direct DNA sequencing based on PCR products. Combined with ND2 gene sequences of the Anas Linnaeus accessed in GenBank, phylogenetic tree was constructed by Neighbor-joining and maximum parsimony methods. [Result] The ND2 gene sequences of 4 Anas platyrhynchos were identical(1 041 bp in length; the nucleotide contents of A, G, T, and C were 28.91%, 13.35%, 20.75% and 36.98% respectively; A+T content approximated to that of C+G). Sequences of ND2 gene of mallard were same as spotbill duck, and had high homology with others. The phylogenetic trees indicated mallard and spotbilled duck were close in genetic relationship, both shared a haplotype; then Philippine duck, green-winged teal and northern pintail fell into branch ''A". [Conclusion] The domestic duck may be domesticated from mallard and spotbilled duck.
文摘[Objective] The aim was to analyze the reasons resulting in the brittleness of Anas crecca crecca.[Method]The structure of the eggshell crushed in hatching process was scanned and its basic elements were analyzed by using electron microscope and Energy Disperse Spectroscopy.[Result]The basic structures of Anas crecca crecca eggs were the same;however,there was great possibility that one of the main reasons affecting hatch ability was the cracks in the outside surface of eff shell.[Conclusion]This study would provide a theoretical basis for the research on artificial in cubation and the egg structure of Anas crecca crecca.
文摘Understanding migratory waterfowl spatiotemporal distributions is important because,in addition to their economic and cultural value,wild waterfowl can be infectious reservoirs of highly pathogenic avian influenza virus(HPAIV).Waterfowl migration has been implicated in regional and intercontinental HPAIV dispersal,and predictive capabilities of where and when HPAIV may be introduced to susceptible spillover hosts would facilitate biosecurity and mitigation efforts.To develop forecasts for HPAIV dispersal,an improved understanding of how individual birds interact with their environment and move on a landscape scale is required.Using an agent-based modeling approach,we integrated individual-scale energetics,species-specific morphology and behavior,and landscape-scale weather and habitat data in a mechanistic stochastic framework to simulate Mallard(Anas platyrhynchos)and Northern Pintail(Anas acuta)annual migration across the Northern Hemisphere.Our model recreated biologically realistic migratory patterns using a first principles approach to waterfowl ecology,behavior,and physiology.Conducting a limited structural sensitivity analysis comparing reduced models to eBird Status and Trends in reference to the full model,we identified density dependence as the main factor influencing spring migration and breeding distributions,and wind as the main factor influencing fall migration and overwintering distributions.We show evidence of weather patterns in Northeast Asia causing significant intercontinental pintail migration to North America.By linking individual energetics to landscapescale processes,we identify key drivers of waterfowl migration while developing a predictive model responsive to daily weather patterns.This model paves the way for future waterfowl migration research predicting HPAIV transmission,climate change impacts,and oil spill effects.
文摘本文在ANA序列下,利用Rosenthal不等式,研究边缘频率插值密度估计的一致强相合性,并在适当的条件下得到其收敛速度,拓展了已有文献的研究。为验证结论的有效性,使用R软件进行数值模拟。模拟结果显示,随着样本量的增大,边缘频率插值密度估计值逐渐趋于真实密度。In this paper, we study the uniform strong consistency and its rate of the density estimation of edge frequency polygons under asymptotically negatively associated (ANA) sequences using Rosenthal-type inequality, which extends the existing studies in the literature. To validate the theoretical conclusions, we conduct numerical simulations in R software. The results demonstrate that the proposed density estimator converges uniformly to the true density as the sample size increases.
基金The National Natural Science Foundation of China under contract Nos 42430107 and 42476176.
文摘A series of 14 destructive wildfires swept across the US West Coast,particularly Southern California,from January 7 to 31,2025.The fires were exacerbated by drought conditions,low humidity,accumulated vegetation from the previous winter,and hurricane-force Santa Ana winds,which in some areas reached speeds of 45 m/s.The wildfires claimed at least 30 lives,forced over 200,000 people to evacuate,destroyed more than 18,000 homes and structures,and burned approximately 233 km^(2)of land in total(Wikipedia,2025).
