HSP90 AA1 is part of the heat shock protein 90 gene family and has important functions against heat stress. We report a case of molecular level parallel evolution of the HSP90 AA1 gene in high elevation amphibians. HS...HSP90 AA1 is part of the heat shock protein 90 gene family and has important functions against heat stress. We report a case of molecular level parallel evolution of the HSP90 AA1 gene in high elevation amphibians. HSP90 AA1 gene sequences of four high-elevation anurans, Bufo gargarizans, Nanorana parkeri, Rana kukunoris, and Scutiger boulengeri, were compared along with five of their low-elevation relatives. A total of 16 amino-acid sites were identified as parallel evolution between N. parkeri and R. kukunoris. We generated both model based(Zhang and Kumar's test) and empirical data based(parallel/divergence plotting) null distributions for non-parallel evolution, and both methods clearly determined that the observed number of parallel substitutions were significantly more than the null expectation. Furthermore, on the HSP90 AA1 gene tree, N. parkeri and R. kukunoris formed a strongly supported clade that was away from their respective relatives. This study provides a clear case of molecular parallel evolution, which may have significant implications in understanding the genetic mechanisms of high-elevation adaptation.展开更多
The continuous growth of air traffic has led to acute airspace congestion and severe delays, which threatens operation safety and cause enormous economic loss. Flight assignment is an economical and effective strategi...The continuous growth of air traffic has led to acute airspace congestion and severe delays, which threatens operation safety and cause enormous economic loss. Flight assignment is an economical and effective strategic plan to reduce the flight delay and airspace congestion by rea- sonably regulating the air traffic flow of China. However, it is a large-scale combinatorial optimiza- tion problem which is difficult to solve. In order to improve the quality of solutions, an effective multi-objective parallel evolution algorithm (MPEA) framework with dynamic migration interval strategy is presented in this work. Firstly, multiple evolution populations are constructed to solve the problem simultaneously to enhance the optimization capability. Then a new strategy is pro- posed to dynamically change the migration interval among different evolution populations to improve the efficiency of the cooperation of populations. Finally, the cooperative co-evolution (CC) algorithm combined with non-dominated sorting genetic algorithm II (NSGA-II) is intro- duced for each population. Empirical studies using the real air traffic data of the Chinese air route network and daily flight plans show that our method outperforms the existing approaches, multi- objective genetic algorithm (MOGA), multi-objective evolutionary algorithm based on decom- position (MOEA/D), CC-based multi-objective algorithm (CCMA) as well as other two MPEAs with different migration interval strategies.展开更多
Dimensional synthesis is one of the most difficult issues in the field of parallel robots with actuation redundancy. To deal with the optimal design of a redundantly actuated parallel robot used for ankle rehabilitati...Dimensional synthesis is one of the most difficult issues in the field of parallel robots with actuation redundancy. To deal with the optimal design of a redundantly actuated parallel robot used for ankle rehabilitation, a methodology of dimensional synthesis based on multi-objective optimization is presented. First, the dimensional synthesis of the redundant parallel robot is formulated as a nonlinear constrained multi-objective optimization problem. Then four objective functions, separately reflecting occupied space, input/output transmission and torque performances, and multi-criteria constraints, such as dimension, interference and kinematics, are defined. In consideration of the passive exercise of plantar/dorsiflexion requiring large output moment, a torque index is proposed. To cope with the actuation redundancy of the parallel robot, a new output transmission index is defined as well. The multi-objective optimization problem is solved by using a modified Differential Evolution(DE) algorithm, which is characterized by new selection and mutation strategies. Meanwhile, a special penalty method is presented to tackle the multi-criteria constraints. Finally, numerical experiments for different optimization algorithms are implemented. The computation results show that the proposed indices of output transmission and torque, and constraint handling are effective for the redundant parallel robot; the modified DE algorithm is superior to the other tested algorithms, in terms of the ability of global search and the number of non-dominated solutions. The proposed methodology of multi-objective optimization can be also applied to the dimensional synthesis of other redundantly actuated parallel robots only with rotational movements.展开更多
Until now the genus Amana(Liliaceae),known as ’East Asian tulips’,has contained just seven species.In this study,a phylogenomic and integrative taxonomic approach was used to reveal two new species,Amana nanyueensis...Until now the genus Amana(Liliaceae),known as ’East Asian tulips’,has contained just seven species.In this study,a phylogenomic and integrative taxonomic approach was used to reveal two new species,Amana nanyueensis from Central China and A.tianmuensis from East China.A.nanyueensis resembles Amana edulis in possessing a densely villous-woolly bulb tunic and two opposite bracts,but differs in its leaves and anthers.Amana tianmuensis resembles Amana erythronioides in possessing three verticillate bracts and yellow anthers,but differs in aspects of its leaves and bulbs.These four species are clearly separated from each other in principal components analysis based on morphology.Phylogenomic analyses based on plastid CDS further support the species delimitation of A.nanyueensis and A.tianmuensis and suggests they are closely related to A.edulis.Cytological analysis shows that A.nanyueensis and A tianmuensis are both diploid(2n=2x=24),different from A edulis,which is either diploid(northern populations) or tetraploid(southern populations,2n=4x=48).The pollen morphology of A.nanyueensis is similar to other Amana species(single-groove germination aperture),but A.tianmuensis is quite different because of the presence of a sulcus membrane,which creates the illusion of double grooves.Ecological niche modelling also revealed a niche differentiation between A.edulis,A.nanyueensis and A.tianmuensis.展开更多
The advanced optimization method named as adaptive range differential evolution (ARDE) is developed. The optimization performance of ARDE is demonstrated using a typical mathematical test and compared with the stand...The advanced optimization method named as adaptive range differential evolution (ARDE) is developed. The optimization performance of ARDE is demonstrated using a typical mathematical test and compared with the standard genetic algorithm and differential evolution. Combined with parallel ARDE, surface modeling method and Navier-Stokes solution, a new automatic aerodynamic optimization method is presented. A low aspect ratio transonic turbine stage is optimized for the maximization of the isentropic efficiency with forty-one design variables in total. The coarse-grained parallel strategy is applied to accelerate the design process using 15 CPUs. The isentropic efficiency of the optimum design is 1.6% higher than that of the reference design. The aerodynamic performance of the optimal design is much better than that of the reference design.展开更多
Aphids harbor primary endosymbionts, Buchnera aphidicola, in specialized cells within their body cavities. Aphids and Buchnera have strict mutualistic relationships in nutrition exchange. This ancient association has ...Aphids harbor primary endosymbionts, Buchnera aphidicola, in specialized cells within their body cavities. Aphids and Buchnera have strict mutualistic relationships in nutrition exchange. This ancient association has received much attention from researchers who are interested in endosymbiotic evolution. Previous studies have foundparallel phylogenetic relationships between non-galling aphids and Buchnera at lower taxonomic levels (genus, species). To understand whether relatively isolated habitats such as galls have effect on the parallel relationships between aphids and Buchnera, the present paper investigated the phylogenetic relationships of gall aphids from Pemphigus and allied genera, which induce pseudo-galls or galls on Populus spp. (poplar) and Buchnera. The molecular phylogenies inferred from three aphid genes (COI, COII and EF-la) andtwo Buchnera genes (gnd, 16S rRNA gene) indicated significant congruence between aphids and Buchnera at generic as well as interspecific levels. Interestingly, both aphid andBuchnera phylogenies supported three main clades corresponding to the galling locations of aphids, namely leaf, the joint of leaf blade and petiole, and branch of the host plant.The results suggest phylogenetic conservatism of gall characters, which indicates gall characters are more strongly affected by aphid phylogeny, rather than host plants.展开更多
We present a molecular phylogenetic study of the lichen genus Sticta focusing on Colombia,using the ITS fungal barcoding gene for a total of 370 ingroup OTUs,with 322 newly generated sequences.The topology resulting f...We present a molecular phylogenetic study of the lichen genus Sticta focusing on Colombia,using the ITS fungal barcoding gene for a total of 370 ingroup OTUs,with 322 newly generated sequences.The topology resulting from a maximum likelihood approach does not support current species concepts in Sticta,which use a morphological concept,but in contrast shows that similar morphodemes evolved multiple times independently within the genus.As a consequence,currently applied names such as S.fuliginosa and S.weigelii comprise numerous(up to more than 20)unrelated species-level lineages,which can be distinguished also phenotypically using previously unrecognized characters such as lobe configuration,lobe surface structure,tomentum type,and anatomy of the basal membrane of the cyphellae.We conclude that the genus Sticta contains about four to five times the number of species currently recognized.In Colombia alone,approximately 150 species of Sticta are present.展开更多
基金supported by the National Nature Science Foundation of China (grant number 31328021 to Jinzhong FU)NSERC of Canada (a discovery grant to Jinzhong FU)
文摘HSP90 AA1 is part of the heat shock protein 90 gene family and has important functions against heat stress. We report a case of molecular level parallel evolution of the HSP90 AA1 gene in high elevation amphibians. HSP90 AA1 gene sequences of four high-elevation anurans, Bufo gargarizans, Nanorana parkeri, Rana kukunoris, and Scutiger boulengeri, were compared along with five of their low-elevation relatives. A total of 16 amino-acid sites were identified as parallel evolution between N. parkeri and R. kukunoris. We generated both model based(Zhang and Kumar's test) and empirical data based(parallel/divergence plotting) null distributions for non-parallel evolution, and both methods clearly determined that the observed number of parallel substitutions were significantly more than the null expectation. Furthermore, on the HSP90 AA1 gene tree, N. parkeri and R. kukunoris formed a strongly supported clade that was away from their respective relatives. This study provides a clear case of molecular parallel evolution, which may have significant implications in understanding the genetic mechanisms of high-elevation adaptation.
基金co-supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (No. 60921001)
文摘The continuous growth of air traffic has led to acute airspace congestion and severe delays, which threatens operation safety and cause enormous economic loss. Flight assignment is an economical and effective strategic plan to reduce the flight delay and airspace congestion by rea- sonably regulating the air traffic flow of China. However, it is a large-scale combinatorial optimiza- tion problem which is difficult to solve. In order to improve the quality of solutions, an effective multi-objective parallel evolution algorithm (MPEA) framework with dynamic migration interval strategy is presented in this work. Firstly, multiple evolution populations are constructed to solve the problem simultaneously to enhance the optimization capability. Then a new strategy is pro- posed to dynamically change the migration interval among different evolution populations to improve the efficiency of the cooperation of populations. Finally, the cooperative co-evolution (CC) algorithm combined with non-dominated sorting genetic algorithm II (NSGA-II) is intro- duced for each population. Empirical studies using the real air traffic data of the Chinese air route network and daily flight plans show that our method outperforms the existing approaches, multi- objective genetic algorithm (MOGA), multi-objective evolutionary algorithm based on decom- position (MOEA/D), CC-based multi-objective algorithm (CCMA) as well as other two MPEAs with different migration interval strategies.
基金Supported by National Natural Science Foundation of China(Grant No.51175029)Beijing Municipal Natural Science Foundation of China(Grant No.3132019)
文摘Dimensional synthesis is one of the most difficult issues in the field of parallel robots with actuation redundancy. To deal with the optimal design of a redundantly actuated parallel robot used for ankle rehabilitation, a methodology of dimensional synthesis based on multi-objective optimization is presented. First, the dimensional synthesis of the redundant parallel robot is formulated as a nonlinear constrained multi-objective optimization problem. Then four objective functions, separately reflecting occupied space, input/output transmission and torque performances, and multi-criteria constraints, such as dimension, interference and kinematics, are defined. In consideration of the passive exercise of plantar/dorsiflexion requiring large output moment, a torque index is proposed. To cope with the actuation redundancy of the parallel robot, a new output transmission index is defined as well. The multi-objective optimization problem is solved by using a modified Differential Evolution(DE) algorithm, which is characterized by new selection and mutation strategies. Meanwhile, a special penalty method is presented to tackle the multi-criteria constraints. Finally, numerical experiments for different optimization algorithms are implemented. The computation results show that the proposed indices of output transmission and torque, and constraint handling are effective for the redundant parallel robot; the modified DE algorithm is superior to the other tested algorithms, in terms of the ability of global search and the number of non-dominated solutions. The proposed methodology of multi-objective optimization can be also applied to the dimensional synthesis of other redundantly actuated parallel robots only with rotational movements.
基金supported by the National Natural Science Foundation of China (Grant No.31970225)the Zhejiang Provincial Natural Science Foundation (Grant No.LY19C030007)theNSFC-NSF Dimensions of Biodiversity Program (Grant No.31461123001)。
文摘Until now the genus Amana(Liliaceae),known as ’East Asian tulips’,has contained just seven species.In this study,a phylogenomic and integrative taxonomic approach was used to reveal two new species,Amana nanyueensis from Central China and A.tianmuensis from East China.A.nanyueensis resembles Amana edulis in possessing a densely villous-woolly bulb tunic and two opposite bracts,but differs in its leaves and anthers.Amana tianmuensis resembles Amana erythronioides in possessing three verticillate bracts and yellow anthers,but differs in aspects of its leaves and bulbs.These four species are clearly separated from each other in principal components analysis based on morphology.Phylogenomic analyses based on plastid CDS further support the species delimitation of A.nanyueensis and A.tianmuensis and suggests they are closely related to A.edulis.Cytological analysis shows that A.nanyueensis and A tianmuensis are both diploid(2n=2x=24),different from A edulis,which is either diploid(northern populations) or tetraploid(southern populations,2n=4x=48).The pollen morphology of A.nanyueensis is similar to other Amana species(single-groove germination aperture),but A.tianmuensis is quite different because of the presence of a sulcus membrane,which creates the illusion of double grooves.Ecological niche modelling also revealed a niche differentiation between A.edulis,A.nanyueensis and A.tianmuensis.
基金This project is supported by Advanced Propulsion Technologies Demonstration Program of Commission of Science Technology and Industry for National Defense of China(No.APTD-0602-04).
文摘The advanced optimization method named as adaptive range differential evolution (ARDE) is developed. The optimization performance of ARDE is demonstrated using a typical mathematical test and compared with the standard genetic algorithm and differential evolution. Combined with parallel ARDE, surface modeling method and Navier-Stokes solution, a new automatic aerodynamic optimization method is presented. A low aspect ratio transonic turbine stage is optimized for the maximization of the isentropic efficiency with forty-one design variables in total. The coarse-grained parallel strategy is applied to accelerate the design process using 15 CPUs. The isentropic efficiency of the optimum design is 1.6% higher than that of the reference design. The aerodynamic performance of the optimal design is much better than that of the reference design.
文摘Aphids harbor primary endosymbionts, Buchnera aphidicola, in specialized cells within their body cavities. Aphids and Buchnera have strict mutualistic relationships in nutrition exchange. This ancient association has received much attention from researchers who are interested in endosymbiotic evolution. Previous studies have foundparallel phylogenetic relationships between non-galling aphids and Buchnera at lower taxonomic levels (genus, species). To understand whether relatively isolated habitats such as galls have effect on the parallel relationships between aphids and Buchnera, the present paper investigated the phylogenetic relationships of gall aphids from Pemphigus and allied genera, which induce pseudo-galls or galls on Populus spp. (poplar) and Buchnera. The molecular phylogenies inferred from three aphid genes (COI, COII and EF-la) andtwo Buchnera genes (gnd, 16S rRNA gene) indicated significant congruence between aphids and Buchnera at generic as well as interspecific levels. Interestingly, both aphid andBuchnera phylogenies supported three main clades corresponding to the galling locations of aphids, namely leaf, the joint of leaf blade and petiole, and branch of the host plant.The results suggest phylogenetic conservatism of gall characters, which indicates gall characters are more strongly affected by aphid phylogeny, rather than host plants.
基金The field work and the molecular studies were partially supported by a grant from the National Science Foundation:Neotropical Epiphytic Microlichens-An Innovative Inventory of a Highly Diverse yet Little Known Group of Symbiotic Organisms(DEB 715660 to The Field Museum,PI R.Lücking)by funds from the Caterpillar®company and Field Museum donor Robert H.Gordon.
文摘We present a molecular phylogenetic study of the lichen genus Sticta focusing on Colombia,using the ITS fungal barcoding gene for a total of 370 ingroup OTUs,with 322 newly generated sequences.The topology resulting from a maximum likelihood approach does not support current species concepts in Sticta,which use a morphological concept,but in contrast shows that similar morphodemes evolved multiple times independently within the genus.As a consequence,currently applied names such as S.fuliginosa and S.weigelii comprise numerous(up to more than 20)unrelated species-level lineages,which can be distinguished also phenotypically using previously unrecognized characters such as lobe configuration,lobe surface structure,tomentum type,and anatomy of the basal membrane of the cyphellae.We conclude that the genus Sticta contains about four to five times the number of species currently recognized.In Colombia alone,approximately 150 species of Sticta are present.