Geographical background and dispersal ability may strongly influence assemblage dissimilarity;however,these aspects have generally been overlooked in previous large-scale beta diversity studies.Here,we examined whethe...Geographical background and dispersal ability may strongly influence assemblage dissimilarity;however,these aspects have generally been overlooked in previous large-scale beta diversity studies.Here,we examined whether the patterns and drivers of taxonomic beta diversity(TBD)and phylogenetic beta diversity(PBD)of breeding birds in China vary across(1)regions on both sides of the Hu Line,which demarcates China’s topographical,climatic,economic,and social patterns,and(2)species with different dispersal ability.TBD and PBD were calculated and partitioned into turnover and nestedness components using a moving window approach.Variables representing climate,habitat heterogeneity,and habitat quality were employed to evaluate the effects of environmental filtering.Spatial distance was considered to assess the impact of dispersal limitation.Variance partitioning analysis was applied to assess the relative roles of these variables.In general,the values of TBD and PBD were high in mountainous areas and were largely determined by environmental filtering.However,different dominant environmental filters on either side of the Hu Line led to divergent beta diversity patterns.Specifically,climate-driven species turnover and habitat heterogeneity-related species nestedness dominated the regions east and west of the line,respectively.Additionally,bird species with stronger dispersal ability were more susceptible to environmental filtering,resulting in more homogeneous assemblages.Our results indicated that regions with distinctive geographical backgrounds may present different ecological factors that lead to divergent assemblage dissimilarity patterns,and dispersal ability determines the response of assemblages to these ecological factors.Identifying a single universal explanation for the observed pattern without considering these aspects may lead to simplistic or incomplete conclusions.Consequently,a comprehensive understanding of large-scale beta diversity patterns and effective planning of conservation strategies necessitate the consideration of both geographical background and species dispersal ability.展开更多
In most studies of tunnel boring machine(TBM)tunnelling, the groundwater pressure was not considered, or was simplified and exerted on the boundary of lining structure. Meanwhile, the leakage, which mainly occurs in t...In most studies of tunnel boring machine(TBM)tunnelling, the groundwater pressure was not considered, or was simplified and exerted on the boundary of lining structure. Meanwhile, the leakage, which mainly occurs in the segment joints, was often ignored in the relevant studies of TBM tunnelling. Additionally, the geological models in these studies were simplified to different extents, and mostly were simplified as homogenous bodies. Considering the deficiencies above, a 3D refined model of the surrounding rock of a tunnel is firstly established using NURBS-TIN-BRe P hybrid data structure in this paper. Then the seepage field of the surrounding rock considering the leakage in the segment joints is simulated. Finally, the stability of TBM water diversion tunnel is studied coupled with the seepage simulation, to analyze the stress-strain conditions, the axial force and the bending moment of tunnel segment considering the leakage in the segment joints. The results illustrate that the maximum radial displacement, the minimum principal stress, the maximum principal stress and the axial force of segment lining considering the seepage effect are all larger than those disregarding the seepage effect.展开更多
Four sets of rice isonuclear-alloplasmic lines including 16 male sterile lines and their maintainer lines were analyzed by using 91 pairs of SSR primers to study the genetic diversity of nuclear genome and their relat...Four sets of rice isonuclear-alloplasmic lines including 16 male sterile lines and their maintainer lines were analyzed by using 91 pairs of SSR primers to study the genetic diversity of nuclear genome and their relative relationships. A total of 169 alleles were detected in the 16 lines, with a frequency of polymorphic loci of 53.85% and an average number of alleles per locus of 1.8, and the average gene diversity was 0.228. Four sets of the isonuclear-alloplasmic male sterile lines shared 146 identical alleles, corresponding to 86.39% of the total alleles; meanwhile, there are 23 different alleles among the tested materials, being 13.61% of the total alleles. On average, 78.70% identical alleles and 21.30% different alleles of the total alleles were detected between the isonuclear-alloplasmic male sterile lines and their maintainer lines. There were 53.85% identical alleles and 46.15% different alleles of the total alleles among the homozygous allonucleus male sterile lines. The fingerprints were established for some male sterile lines and maintainer lines. All the materials tested were divided into three groups at the 0.2 genetic distance based on the cluster analysis. Eight lines of Huanong A and Huayu A (including Huanong B and Huayu B) were in the first group, four lines of Kezhen A (including Kezhen B) in the second group, and four lines of Zhenshan 97A (including Zhenshan 97B) in the third group. For the isonuclear-alloplasmic male sterile lines, the similarity coefficient between Y (Yegong) type and WA (wild abortive) type or between CW (Raoping wild rice) and WA type reached 87-98%.展开更多
Genetic diversity is one of the useful tools to select appropriate lines for hybridization. Twenty short</span><span style="font-family:Verdana;">-</span><span style="font-family:Ve...Genetic diversity is one of the useful tools to select appropriate lines for hybridization. Twenty short</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">statured</span><span style="font-family:""> </span><span style="font-family:Verdana;">maize inbred lines were taken for present study</span><span style="font-family:Verdana;">,</span><span style="font-family:""> </span><span style="font-family:Verdana;">which</span><span style="font-family:""><span style="font-family:Verdana;"> were collected from CIMMYT India and Mexico through Plant Breeding Division, Bangladesh Agricultural Research Institute (BARI), Gazipu</span><span style="font-family:Verdana;">r. This experiment was conducted </span></span><span style="font-family:Verdana;">from</span><span style="font-family:Verdana;"> November 2015 to April 2016 t</span><span style="font-family:Verdana;">o identify parental lines to produce single cross short statured</span><span style="font-family:""> </span><span style="font-family:Verdana;">maize hyb</span><span style="font-family:""><span style="font-family:Verdana;">rids. </span><span style="font-family:Verdana;">From th</span></span><span style="font-family:Verdana;">e</span><span style="font-family:Verdana;"> genetic diversity studies</span><span style="font-family:Verdana;">,</span><span style="font-family:""> </span><span style="font-family:Verdana;">the </span><span style="font-family:Verdana;">importance of both additive and non-additive</span><span style="font-family:Verdana;"> gene actions for the expression of yield and yield contributing characters were found. Values of vector I and II revealed that both the vectors had positive values for date of silking, plant height, rows/cob, grains/row and yield. These results indicated that these five characters had highest contribution towards divergence. Based on </span><span style="font-family:Verdana;">the </span><span style="font-family:""><span style="font-family:Verdana;">relative magnitude of D</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> values;20 inbred lines were grouped into five clusters. Seven inbred lines were selected on the basis of genetic diversity and per se performance which will be crossed separately in a half</span></span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">diallel fashion to develop hybrids.展开更多
This paper used SSR molecular markers to perform the genetic diversity analysis on 13 ordinary inbred lines of maize of different sources in order to divide heterotic groups of maize inbred line and predict heterosis....This paper used SSR molecular markers to perform the genetic diversity analysis on 13 ordinary inbred lines of maize of different sources in order to divide heterotic groups of maize inbred line and predict heterosis. Using 12 pairs of SSR primers,a total of 47 allelic variants were detected in 13 inbred lines,2-5 alleles were detected for each pair of primers,an average of 3. 9,and polymorphism information content varied from 0. 379 to 0. 828. According to the cluster analysis,the 13 inbred lines could be divided into 5 groups.展开更多
基金supported by the National Natural Science Foundation of China(31901220)Science and Technology Planning Project of Guangdong Province,China(2019B121202004)+1 种基金Guangdong Basic and Applied Basic Research Foundation(2021A1515110744)Forestry Administration of Guangdong Province(DFGP Project of Fauna of Guangdong-202115)。
文摘Geographical background and dispersal ability may strongly influence assemblage dissimilarity;however,these aspects have generally been overlooked in previous large-scale beta diversity studies.Here,we examined whether the patterns and drivers of taxonomic beta diversity(TBD)and phylogenetic beta diversity(PBD)of breeding birds in China vary across(1)regions on both sides of the Hu Line,which demarcates China’s topographical,climatic,economic,and social patterns,and(2)species with different dispersal ability.TBD and PBD were calculated and partitioned into turnover and nestedness components using a moving window approach.Variables representing climate,habitat heterogeneity,and habitat quality were employed to evaluate the effects of environmental filtering.Spatial distance was considered to assess the impact of dispersal limitation.Variance partitioning analysis was applied to assess the relative roles of these variables.In general,the values of TBD and PBD were high in mountainous areas and were largely determined by environmental filtering.However,different dominant environmental filters on either side of the Hu Line led to divergent beta diversity patterns.Specifically,climate-driven species turnover and habitat heterogeneity-related species nestedness dominated the regions east and west of the line,respectively.Additionally,bird species with stronger dispersal ability were more susceptible to environmental filtering,resulting in more homogeneous assemblages.Our results indicated that regions with distinctive geographical backgrounds may present different ecological factors that lead to divergent assemblage dissimilarity patterns,and dispersal ability determines the response of assemblages to these ecological factors.Identifying a single universal explanation for the observed pattern without considering these aspects may lead to simplistic or incomplete conclusions.Consequently,a comprehensive understanding of large-scale beta diversity patterns and effective planning of conservation strategies necessitate the consideration of both geographical background and species dispersal ability.
基金Supported by the Foundation for Innovation Research Groups of the National Natural Science Foundation of China(No.51321065)Tianjin Research Program of Application Foundation and Advanced Technology(No.12JCZDJC29200)Tianjin Natural Science Foundation(No.13JCYBJC19500)
文摘In most studies of tunnel boring machine(TBM)tunnelling, the groundwater pressure was not considered, or was simplified and exerted on the boundary of lining structure. Meanwhile, the leakage, which mainly occurs in the segment joints, was often ignored in the relevant studies of TBM tunnelling. Additionally, the geological models in these studies were simplified to different extents, and mostly were simplified as homogenous bodies. Considering the deficiencies above, a 3D refined model of the surrounding rock of a tunnel is firstly established using NURBS-TIN-BRe P hybrid data structure in this paper. Then the seepage field of the surrounding rock considering the leakage in the segment joints is simulated. Finally, the stability of TBM water diversion tunnel is studied coupled with the seepage simulation, to analyze the stress-strain conditions, the axial force and the bending moment of tunnel segment considering the leakage in the segment joints. The results illustrate that the maximum radial displacement, the minimum principal stress, the maximum principal stress and the axial force of segment lining considering the seepage effect are all larger than those disregarding the seepage effect.
基金the Natural Science Foundation of Guangdong Province (Grant No. 032244) the Natural Science Foundation of Guangdong Education Department (Grant No. Z03004).
文摘Four sets of rice isonuclear-alloplasmic lines including 16 male sterile lines and their maintainer lines were analyzed by using 91 pairs of SSR primers to study the genetic diversity of nuclear genome and their relative relationships. A total of 169 alleles were detected in the 16 lines, with a frequency of polymorphic loci of 53.85% and an average number of alleles per locus of 1.8, and the average gene diversity was 0.228. Four sets of the isonuclear-alloplasmic male sterile lines shared 146 identical alleles, corresponding to 86.39% of the total alleles; meanwhile, there are 23 different alleles among the tested materials, being 13.61% of the total alleles. On average, 78.70% identical alleles and 21.30% different alleles of the total alleles were detected between the isonuclear-alloplasmic male sterile lines and their maintainer lines. There were 53.85% identical alleles and 46.15% different alleles of the total alleles among the homozygous allonucleus male sterile lines. The fingerprints were established for some male sterile lines and maintainer lines. All the materials tested were divided into three groups at the 0.2 genetic distance based on the cluster analysis. Eight lines of Huanong A and Huayu A (including Huanong B and Huayu B) were in the first group, four lines of Kezhen A (including Kezhen B) in the second group, and four lines of Zhenshan 97A (including Zhenshan 97B) in the third group. For the isonuclear-alloplasmic male sterile lines, the similarity coefficient between Y (Yegong) type and WA (wild abortive) type or between CW (Raoping wild rice) and WA type reached 87-98%.
文摘Genetic diversity is one of the useful tools to select appropriate lines for hybridization. Twenty short</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">statured</span><span style="font-family:""> </span><span style="font-family:Verdana;">maize inbred lines were taken for present study</span><span style="font-family:Verdana;">,</span><span style="font-family:""> </span><span style="font-family:Verdana;">which</span><span style="font-family:""><span style="font-family:Verdana;"> were collected from CIMMYT India and Mexico through Plant Breeding Division, Bangladesh Agricultural Research Institute (BARI), Gazipu</span><span style="font-family:Verdana;">r. This experiment was conducted </span></span><span style="font-family:Verdana;">from</span><span style="font-family:Verdana;"> November 2015 to April 2016 t</span><span style="font-family:Verdana;">o identify parental lines to produce single cross short statured</span><span style="font-family:""> </span><span style="font-family:Verdana;">maize hyb</span><span style="font-family:""><span style="font-family:Verdana;">rids. </span><span style="font-family:Verdana;">From th</span></span><span style="font-family:Verdana;">e</span><span style="font-family:Verdana;"> genetic diversity studies</span><span style="font-family:Verdana;">,</span><span style="font-family:""> </span><span style="font-family:Verdana;">the </span><span style="font-family:Verdana;">importance of both additive and non-additive</span><span style="font-family:Verdana;"> gene actions for the expression of yield and yield contributing characters were found. Values of vector I and II revealed that both the vectors had positive values for date of silking, plant height, rows/cob, grains/row and yield. These results indicated that these five characters had highest contribution towards divergence. Based on </span><span style="font-family:Verdana;">the </span><span style="font-family:""><span style="font-family:Verdana;">relative magnitude of D</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> values;20 inbred lines were grouped into five clusters. Seven inbred lines were selected on the basis of genetic diversity and per se performance which will be crossed separately in a half</span></span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">diallel fashion to develop hybrids.
文摘This paper used SSR molecular markers to perform the genetic diversity analysis on 13 ordinary inbred lines of maize of different sources in order to divide heterotic groups of maize inbred line and predict heterosis. Using 12 pairs of SSR primers,a total of 47 allelic variants were detected in 13 inbred lines,2-5 alleles were detected for each pair of primers,an average of 3. 9,and polymorphism information content varied from 0. 379 to 0. 828. According to the cluster analysis,the 13 inbred lines could be divided into 5 groups.