How do you get information from an article as much and fast as possible while you are reading? It is a very important thing for us——Chinese readers. Reading is an important element in our English study. Mastering re...How do you get information from an article as much and fast as possible while you are reading? It is a very important thing for us——Chinese readers. Reading is an important element in our English study. Mastering reading skills will help increase our reading speed and comprehend what we read. Now several reading skills are to be discussed in this paper.展开更多
Numerical simulation of stepped channel flow was conducted using turbulence models based on the VOF technique. Stepped channel flow is a complicated air-water two-phase flow with free surface, which can be divided int...Numerical simulation of stepped channel flow was conducted using turbulence models based on the VOF technique. Stepped channel flow is a complicated air-water two-phase flow with free surface, which can be divided into three flow regimes： skimming flow, nappe flow and transition flow. The characteristics of skimming flow over mild stepped channel was investigated, including friction factors, air concentration profiles velocity field, clear-water and bulked depths, static pressure, etc. Smooth channel flow was also simulated to compare the hydraulic characteristics of the stepped channel flow with the smooth one. Comparisons between the computed and the measured were made. Furthermore, comparison of the computed air concentration with Straub and Anderson＇s data was also performed. The Fluent 6.1 software was employed to conduct this numerical simulation work.展开更多
Shibataea is a genus of temperate bamboos(Poaceae:Bambusoideae)endemic to China,but little is known about its phylogenetic position and interspecific relationships.To elucidate the phylogenetic relationship of the bam...Shibataea is a genus of temperate bamboos(Poaceae:Bambusoideae)endemic to China,but little is known about its phylogenetic position and interspecific relationships.To elucidate the phylogenetic relationship of the bamboo genus Shibataea,we performed genome-scale phylogenetic analysis of all seven species and one variety of the genus using double digest restriction-site associated DNA sequencing(dd RAD-seq)and whole plastid genomes generated using genome skimming.Our phylogenomic analyses based on dd RAD-seq and plastome data congruently recovered Shibataea as monophyletic.The nuclear data resolved S.hispida as the earliest diverged species,followed by S.chinensis,while the rest of Shibataea can be further divided into two clades.However,the plastid and nuclear topologies conflict significantly.By comparing the results of network analysis and topologies reconstructed from different datasets,we identify S.kumasasa as the most admixed species,which may be caused by incomplete lineage sorting(ILS)or interspecific gene flow with four sympatric species.This study highlights the power of dd RAD and plastome data in resolving complex relationships in the intractable bamboo genus.展开更多
The rapid expansion of next-generation sequencing （NGS） has generated a powerful array of approaches to address fundamental questions in biology. Several genome-partitioning strategies to sequence selected subsets o...The rapid expansion of next-generation sequencing （NGS） has generated a powerful array of approaches to address fundamental questions in biology. Several genome-partitioning strategies to sequence selected subsets of the genome have emerged in the fields of phylogenomics and evolutionary genomics. In this review, we summarize the applications, advantages and limitations of four NGS-based genome- partitioning approaches in plant phylogenomics： genome skimming, transcriptome sequencing （RNA- seq）, restriction site associated DNA sequencing （RAD-Seq）, and targeted capture （Hyb-seq）. Of these four genome-partitioning approaches, targeted capture （especially Hyb-seq） shows the greatest promise for plant phy^ogenetics over the next fex~ years. This reviex~ wi~ aid ~esea^chers in their selection of appropriate genome-partitioning approaches to address questions of evolutionary scale, where we anticipate continued development and expansion ofwhole-genome sequencing strategies in the fields of plant phylogenomics and evolutionary biology research.展开更多
This paper has proposed a new modelling and simulating technique for the echo of the semi-active radar seeker against the sea skimming target. The echo modelling is based on the electromagnetic scattering mechanisms. ...This paper has proposed a new modelling and simulating technique for the echo of the semi-active radar seeker against the sea skimming target. The echo modelling is based on the electromagnetic scattering mechanisms. A modified Four-path model based on the radar detection scene is used to describe the multipath scattering between the target and rough sea surface. A Facet-based Small Slope Approximation (FBSSA) method is employed to calculate the scattering from the sea surface. The Physical Optics (PO) and the Equivalent Edge Current (EEC) Method is used to calculate the target scattering. In the echo simulations. The results present the original echo and the echo processed by the signal processing procedures, where the clutter and multipath effect can be observed.展开更多
The genus Corydalis, with ca. 530 species, has long been considered taxonomically challenging because of its great variability. Previous molecular analyses,based on a few molecular markers and incomplete taxonomic sam...The genus Corydalis, with ca. 530 species, has long been considered taxonomically challenging because of its great variability. Previous molecular analyses,based on a few molecular markers and incomplete taxonomic sampling, were clearly inadequate to delimit sections and subgenera. We have performed phylogenetic analyses of Corydalis and related taxa,using 65 shared protein-coding plastid genes from313 accessions(including 280 samples of ca. 226species of Corydalis) and 152 universal low-copy nuclear genes from 296 accessions(including 271samples of Corydalis) covering all 42 previously recognized sections and five independent “series”.Phylogenetic trees were inferred using Bayesian Inference and Maximum Likelihood. Eight selected morphological characters were estimated using ancestral state reconstructions. Results include:(i) of the three subgenera of Corydalis, two are fully supported by both the plastid and nuclear data;the third,subg. Cremnocapnos, is weakly supported by plastid DNA only, whereas in the nuclear data the two included sections form successive outgroups to the rest of the genus;(ii) among all 42 sections and five“series”, 25 sections and one “series” are resolved as monophyletic in both data sets;(iii) the common ancestor of Corydalis is likely to be a perennial plant with a taproot, yellow flowers with a short saccate spur, linear fruits with recurved fruiting pedicels, and seeds with elaiosomes;(iv) we provide a new classification of Corydalis with four subgenera(of which subg. Bipapillatae is here newly described), 39 sections, 16 of which are consistent with the previous classification, 16 sections have been recircumscribed, one section has been reinstated and six new sections are established. Characters associated with lifespan, underground structures, floral spur, fruit and elaiosomes are important for the recognition of subgenera and sections. These new phylogenetic analyses combined with ancestral character reconstructions uncovered previously unrecognized relationships, and展开更多
Genome skimming has dramatically extended DNA barcoding from short DNA fragments to next generation barcodes in plants.However,conserved DNA barcoding markers,including complete plastid genome and nuclear ribosomal DN...Genome skimming has dramatically extended DNA barcoding from short DNA fragments to next generation barcodes in plants.However,conserved DNA barcoding markers,including complete plastid genome and nuclear ribosomal DNA(nrDNA)sequences,are inadequate for accurate species identification.Skmer,a recently proposed approach that estimates genetic distances among species based on unassembled genome skims,has been proposed to effectively improve species discrimination rate.In this study,we used Skmer to identify species based on genomic skims of 47 individuals representing 10 out of 13 species of Schima(Theaceae)from China.The unassembled reads identified six species,with a species identification rate of 60%,twice as high as previous efforts that used plastid genomes(27.27%).In addition,Skmer was able to identify Schima species with only 0.5sequencing depth,as six species were well-supported with unassembled data sizes as small as 0.5 Gb.These findings demonstrate the potential for Skmer approach in species identification,where nuclear genomic data plays a crucial role.For taxonomically difficult taxa such as Schima,which have diverged recently and have low levels of genetic variation,Skmer is a promising alternative to next generation barcodes.展开更多
文摘How do you get information from an article as much and fast as possible while you are reading? It is a very important thing for us——Chinese readers. Reading is an important element in our English study. Mastering reading skills will help increase our reading speed and comprehend what we read. Now several reading skills are to be discussed in this paper.
文摘Numerical simulation of stepped channel flow was conducted using turbulence models based on the VOF technique. Stepped channel flow is a complicated air-water two-phase flow with free surface, which can be divided into three flow regimes： skimming flow, nappe flow and transition flow. The characteristics of skimming flow over mild stepped channel was investigated, including friction factors, air concentration profiles velocity field, clear-water and bulked depths, static pressure, etc. Smooth channel flow was also simulated to compare the hydraulic characteristics of the stepped channel flow with the smooth one. Comparisons between the computed and the measured were made. Furthermore, comparison of the computed air concentration with Straub and Anderson＇s data was also performed. The Fluent 6.1 software was employed to conduct this numerical simulation work.
基金supported by the National Natural Science Foundation of China (Grant No. 31470322 and 31430011)
文摘Shibataea is a genus of temperate bamboos(Poaceae:Bambusoideae)endemic to China,but little is known about its phylogenetic position and interspecific relationships.To elucidate the phylogenetic relationship of the bamboo genus Shibataea,we performed genome-scale phylogenetic analysis of all seven species and one variety of the genus using double digest restriction-site associated DNA sequencing(dd RAD-seq)and whole plastid genomes generated using genome skimming.Our phylogenomic analyses based on dd RAD-seq and plastome data congruently recovered Shibataea as monophyletic.The nuclear data resolved S.hispida as the earliest diverged species,followed by S.chinensis,while the rest of Shibataea can be further divided into two clades.However,the plastid and nuclear topologies conflict significantly.By comparing the results of network analysis and topologies reconstructed from different datasets,we identify S.kumasasa as the most admixed species,which may be caused by incomplete lineage sorting(ILS)or interspecific gene flow with four sympatric species.This study highlights the power of dd RAD and plastome data in resolving complex relationships in the intractable bamboo genus.
基金supported by the Large-scale Scientific Facilities of the Chinese Academy of Sciences (Grant No: 2017-LSFGBOWS-01)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB31000000)the Program of Science and Technology Talents Training of Yunnan Province (2017HA014)
文摘The rapid expansion of next-generation sequencing （NGS） has generated a powerful array of approaches to address fundamental questions in biology. Several genome-partitioning strategies to sequence selected subsets of the genome have emerged in the fields of phylogenomics and evolutionary genomics. In this review, we summarize the applications, advantages and limitations of four NGS-based genome- partitioning approaches in plant phylogenomics： genome skimming, transcriptome sequencing （RNA- seq）, restriction site associated DNA sequencing （RAD-Seq）, and targeted capture （Hyb-seq）. Of these four genome-partitioning approaches, targeted capture （especially Hyb-seq） shows the greatest promise for plant phy^ogenetics over the next fex~ years. This reviex~ wi~ aid ~esea^chers in their selection of appropriate genome-partitioning approaches to address questions of evolutionary scale, where we anticipate continued development and expansion ofwhole-genome sequencing strategies in the fields of plant phylogenomics and evolutionary biology research.
文摘This paper has proposed a new modelling and simulating technique for the echo of the semi-active radar seeker against the sea skimming target. The echo modelling is based on the electromagnetic scattering mechanisms. A modified Four-path model based on the radar detection scene is used to describe the multipath scattering between the target and rough sea surface. A Facet-based Small Slope Approximation (FBSSA) method is employed to calculate the scattering from the sea surface. The Physical Optics (PO) and the Equivalent Edge Current (EEC) Method is used to calculate the target scattering. In the echo simulations. The results present the original echo and the echo processed by the signal processing procedures, where the clutter and multipath effect can be observed.
基金supported by grants from the Second Tibetan Plateau Scientific Expedition and Research (STEP) program (2019QZKK0502)the Key R&D Program of Yunnan Province (202103AF140005)+6 种基金the National Natural Science Foundation of China (32170215 and 32100187)the National Natural Science Foundation of China-Yunnan Joint Fund to Support Key Projects (U1802232)Strategic Priority Research Program of Chinese Academy of Sciences(XDA20050203)International Partnership Program of Chinese Academy of Sciences (151853KYSB20180009)Yunnan Young&Elite Talents Project (YNWR-QNBJ-2019-033)Ten Thousand Talents Program of Yunnan Province (202005AB160005)Chinese Academy of Sciences “Light of West China” Program。
文摘The genus Corydalis, with ca. 530 species, has long been considered taxonomically challenging because of its great variability. Previous molecular analyses,based on a few molecular markers and incomplete taxonomic sampling, were clearly inadequate to delimit sections and subgenera. We have performed phylogenetic analyses of Corydalis and related taxa,using 65 shared protein-coding plastid genes from313 accessions(including 280 samples of ca. 226species of Corydalis) and 152 universal low-copy nuclear genes from 296 accessions(including 271samples of Corydalis) covering all 42 previously recognized sections and five independent “series”.Phylogenetic trees were inferred using Bayesian Inference and Maximum Likelihood. Eight selected morphological characters were estimated using ancestral state reconstructions. Results include:(i) of the three subgenera of Corydalis, two are fully supported by both the plastid and nuclear data;the third,subg. Cremnocapnos, is weakly supported by plastid DNA only, whereas in the nuclear data the two included sections form successive outgroups to the rest of the genus;(ii) among all 42 sections and five“series”, 25 sections and one “series” are resolved as monophyletic in both data sets;(iii) the common ancestor of Corydalis is likely to be a perennial plant with a taproot, yellow flowers with a short saccate spur, linear fruits with recurved fruiting pedicels, and seeds with elaiosomes;(iv) we provide a new classification of Corydalis with four subgenera(of which subg. Bipapillatae is here newly described), 39 sections, 16 of which are consistent with the previous classification, 16 sections have been recircumscribed, one section has been reinstated and six new sections are established. Characters associated with lifespan, underground structures, floral spur, fruit and elaiosomes are important for the recognition of subgenera and sections. These new phylogenetic analyses combined with ancestral character reconstructions uncovered previously unrecognized relationships, and
基金supported by National Natural Science Foundation of China(No.32070369)the Youth Innovation Promotion Association CAS of China(No.2021393)+1 种基金the Yunnan Revitalization Talent Support Program“Young Talent”Project,the Applied Fundamental Research Foundation of Yunnan Province(202301AT070308)the Fund of Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology(YNPRAEC-2023006).
文摘Genome skimming has dramatically extended DNA barcoding from short DNA fragments to next generation barcodes in plants.However,conserved DNA barcoding markers,including complete plastid genome and nuclear ribosomal DNA(nrDNA)sequences,are inadequate for accurate species identification.Skmer,a recently proposed approach that estimates genetic distances among species based on unassembled genome skims,has been proposed to effectively improve species discrimination rate.In this study,we used Skmer to identify species based on genomic skims of 47 individuals representing 10 out of 13 species of Schima(Theaceae)from China.The unassembled reads identified six species,with a species identification rate of 60%,twice as high as previous efforts that used plastid genomes(27.27%).In addition,Skmer was able to identify Schima species with only 0.5sequencing depth,as six species were well-supported with unassembled data sizes as small as 0.5 Gb.These findings demonstrate the potential for Skmer approach in species identification,where nuclear genomic data plays a crucial role.For taxonomically difficult taxa such as Schima,which have diverged recently and have low levels of genetic variation,Skmer is a promising alternative to next generation barcodes.
