[Objective]Implementation of the Ten-Year Fishing Ban policy may alter fish diversity and niche characteristics of dominant species in spawning grounds within the National Nature Reserve for Rare and Endemic Fish in t...[Objective]Implementation of the Ten-Year Fishing Ban policy may alter fish diversity and niche characteristics of dominant species in spawning grounds within the National Nature Reserve for Rare and Endemic Fish in the Upper Yangtze River.This study initiated continuous monitoring of natural spawning habitats from February 2022 to assess these ecological changes.[Methods]Environmental DNA(eDNA)metabarcoding was employed to analyze fish species composition,biodiversity patterns,and niche parameters of dominant species.Water sampling followed the CEN/TS 19461 standard across five monitoring transects(ZT1-ZT5).[Results]The eDNA analysis detected 45 species of fish belonging to 38 genera,13 families,and 3 orders were detected through environmental DNA(eDNA)in this survey,including 10 species endemic to the upper reaches of the Yangtze River,such as Procypris rabaudi and Myxocyprinus asiaticus.The fish community was mainly composed of bottom-dwelling,settling ovum-producing,omnivorous fish.The variation ranges of the Chao1 index,ACE index,Shannon index,and Simpson index are 736~996,719~965,1.58~3.23,and 0.83~0.99,respectively,indicating that fish species in spawning sites are abundant and community distribution uniformity is high.All indexes are highest at ZT1 monitoring points.Cluster analysis showed that,at a certain similarity level,fish community types in spawning sites could be basically divided into two groups:ZT1,ZT3,and ZT5 clustered together,and ZT2 and ZT4 clustered together,indicating similar fish community habitats.There are 9 dominant fish species in typical deep pool habitats in the reserve,with niche widths(Bi)ranging from 1.13 to 3.87.The dominant fish species are broad and medium niche fish,such as Cyprinus carpio and Hemiculter tchangi,with the niche overlap index(Oik)of some dominant fish species reaching more than 0.95.This indicates fierce competition for resources among the fish in this spawning ground.[Conclusion]The Zhutuo spawning ground demonstrates high species richness with homogeneous community structure and intense resource competition.This study establishes an eDNA-based monitoring framework that enhances conventional survey method,providing critical baseline data for adaptive management under the fishing moratorium regime.展开更多
This paper presented a conceptual framework to country competitiveness using the Index of Competitiveness （IVCR）, revealed for Ecuador to determine the most competitive and potential products exported to China; also...This paper presented a conceptual framework to country competitiveness using the Index of Competitiveness （IVCR）, revealed for Ecuador to determine the most competitive and potential products exported to China; also measured the export complementarities through other indicators and by comparison with similar products exported by competing countries. This study used the 6-digit Harmonized System （HS） and the 10-digit NANDINA tariff codes for more specific items. Thereby we can identify trends that allow the Ecuadorian authorities analyze the state of bilateral agreements and develop action strategies, moreover help exporters identify potential market niches, considering that China is currently one of the developing countries with higher growth and expanding economy. The results showed that the most competitive agricultural products consisted on fish flour, bovine skins, mollusks, fish wastes and cocoa grains. The founded potential products were broad beans, fruits, fish viscera, algae, alpaca hair or hair wastes. Nevertheless these were none adding value commodities we need to fred some mechanisms to deepen the exportable offer of value-added goods.展开更多
This paper introduces niching particle swarm optimiza- tion （nichePSO） into clustering analysis and puts forward a cluster- ing algorithm which uses nichePSO to optimize density functions. Firstly, this paper improv...This paper introduces niching particle swarm optimiza- tion （nichePSO） into clustering analysis and puts forward a cluster- ing algorithm which uses nichePSO to optimize density functions. Firstly, this paper improves main swarm training models and in- creases their ability of space searching. Secondly, the radius of sub-swarms is defined adaptively according to the actual clus- tering problem, which can be useful for the niches＇ forming and searching. At last, a novel method that distributes samples to the corresponding cluster is proposed. Numerical results illustrate that this algorithm based on the density function and nichePSO could cluster unbalanced density datasets into the correct clusters auto- matically and accurately.展开更多
This study analyzes drift phenomena of deterministic crowding and probabilistic crowding by using equivalence class model and expectation proportion equations. It is proved that the replacement errors of deterministic...This study analyzes drift phenomena of deterministic crowding and probabilistic crowding by using equivalence class model and expectation proportion equations. It is proved that the replacement errors of deterministic crowding cause the population converging to a single individual, thus resulting in premature stagnation or losing optional optima. And probabilistic crowding can maintain equilibrium multiple subpopulations as the population size is adequate large. An improved niching method using clustering crowding is proposed. By analyzing topology of fitness landscape using hill valley function and extending the search space for similarity analysis, clustering crowding determines the locality of search space more accurately, thus greatly decreasing replacement errors of crowding. The integration of deterministic and probabilistic replacement increases the capacity of both parallel local hill climbing and maintaining multiple subpopulations. The experimental results optimizing various multimodal functions show that,the performances of clustering crowding, such as the number of effective peaks maintained, average peak ratio and global optimum ratio are uniformly superior to those of the evolutionary algorithms using fitness sharing, simple deterministic crowding and probabilistic crowding.展开更多
Introduction Glioblastoma multiforme(GBM),a malignant brain tumor,is highly invasive and use brain microvessels to migrate and invade.Studying the perivascular invasion/migration of GBM may enable new possibilities in...Introduction Glioblastoma multiforme(GBM),a malignant brain tumor,is highly invasive and use brain microvessels to migrate and invade.Studying the perivascular invasion/migration of GBM may enable new possibilities in GBM therapy.However,the lack proper 3D study models that recapitulate GBM hallmarks restricts investigating cell-cell/cell-molecular interactions in tumor microenvironments.In this study,we created GBM-vascular niche models through 3D bioprinting [1-2] using patient-derived GBM cells with sternness(GSC:glioblastoma stem cells),vasculature endothelial cells(ECs),mural cells,and various hydrogels.Materials and methods Three GBM-vascular models were designed:Model A with large vessels and GBM spheroid;Model B with large-and micro-vessels,and GBM spheroid;Model C with large-and micro-vessels and scattered GBM cells.Large channels were created by sacrificial bioprinting.Microvessel network was formed through self-assembly of ECs(HUVEC or brain EC)and mural cells(fibroblast,pericytes,and/or astrocytes).Three GBM cell types were used in the study:SD02 and SD03 are GSCs;U87MG is a commercially-available GBM cell line.Collagen type I or fibrin hydrogel have been used as major scaffold materials.For drug treatment,Temozolomide in culture medium was perfused through large vasculatures in Model A.Results and discussion Three different GBM-vascular models were successfully fabricated and culture for 2-10.GSCs cultured in these models maintained sternness and heterogeneity during the long-term cultures.In Model A,GSCs actively invaded into the surrounding tissues(~Day26),initially regressed in response to the drug(~Day50),then developed therapeutic resistance and resumed aggressive invasion(~Day57).In Model B and C,three GBM types presented distinctive invasion patterns and EC-interactions.SD02 cells showed a spiky invasion pattern with elongated morphology.SD03 cells showed a more dispersed invasion pattern with many single cell migrations towards surrounding microvessels.U87MG cells showed a blunt invasion pattern,caused EC death in the spheroid form;however,the EC death was significantly reduced in the scattered single cell form.Conclusions In this study,we have created GBM-vascular niche models that can recapitulate various GBM characteristics such as cancer sternness,tumor type-specific invasion patterns,and drug responses with therapeutic resistance.Our models have a great potential in investigating patient-specific tumor behaviors under chemo-/radio-therapy conditions and consequentially helping to tailor personalized treatment strategy.The model platform is capable of modifying multiples variables including ECMs,cell types,vascular structures,and dynamic culture condition.Thus,it can be adapted to other biological systems and serve as a valuable tool for generating customized microenvironments.展开更多
文摘[Objective]Implementation of the Ten-Year Fishing Ban policy may alter fish diversity and niche characteristics of dominant species in spawning grounds within the National Nature Reserve for Rare and Endemic Fish in the Upper Yangtze River.This study initiated continuous monitoring of natural spawning habitats from February 2022 to assess these ecological changes.[Methods]Environmental DNA(eDNA)metabarcoding was employed to analyze fish species composition,biodiversity patterns,and niche parameters of dominant species.Water sampling followed the CEN/TS 19461 standard across five monitoring transects(ZT1-ZT5).[Results]The eDNA analysis detected 45 species of fish belonging to 38 genera,13 families,and 3 orders were detected through environmental DNA(eDNA)in this survey,including 10 species endemic to the upper reaches of the Yangtze River,such as Procypris rabaudi and Myxocyprinus asiaticus.The fish community was mainly composed of bottom-dwelling,settling ovum-producing,omnivorous fish.The variation ranges of the Chao1 index,ACE index,Shannon index,and Simpson index are 736~996,719~965,1.58~3.23,and 0.83~0.99,respectively,indicating that fish species in spawning sites are abundant and community distribution uniformity is high.All indexes are highest at ZT1 monitoring points.Cluster analysis showed that,at a certain similarity level,fish community types in spawning sites could be basically divided into two groups:ZT1,ZT3,and ZT5 clustered together,and ZT2 and ZT4 clustered together,indicating similar fish community habitats.There are 9 dominant fish species in typical deep pool habitats in the reserve,with niche widths(Bi)ranging from 1.13 to 3.87.The dominant fish species are broad and medium niche fish,such as Cyprinus carpio and Hemiculter tchangi,with the niche overlap index(Oik)of some dominant fish species reaching more than 0.95.This indicates fierce competition for resources among the fish in this spawning ground.[Conclusion]The Zhutuo spawning ground demonstrates high species richness with homogeneous community structure and intense resource competition.This study establishes an eDNA-based monitoring framework that enhances conventional survey method,providing critical baseline data for adaptive management under the fishing moratorium regime.
文摘This paper presented a conceptual framework to country competitiveness using the Index of Competitiveness （IVCR）, revealed for Ecuador to determine the most competitive and potential products exported to China; also measured the export complementarities through other indicators and by comparison with similar products exported by competing countries. This study used the 6-digit Harmonized System （HS） and the 10-digit NANDINA tariff codes for more specific items. Thereby we can identify trends that allow the Ecuadorian authorities analyze the state of bilateral agreements and develop action strategies, moreover help exporters identify potential market niches, considering that China is currently one of the developing countries with higher growth and expanding economy. The results showed that the most competitive agricultural products consisted on fish flour, bovine skins, mollusks, fish wastes and cocoa grains. The founded potential products were broad beans, fruits, fish viscera, algae, alpaca hair or hair wastes. Nevertheless these were none adding value commodities we need to fred some mechanisms to deepen the exportable offer of value-added goods.
基金supported by the National Natural Science Foundation of China (708710157103100271171030)
文摘This paper introduces niching particle swarm optimiza- tion （nichePSO） into clustering analysis and puts forward a cluster- ing algorithm which uses nichePSO to optimize density functions. Firstly, this paper improves main swarm training models and in- creases their ability of space searching. Secondly, the radius of sub-swarms is defined adaptively according to the actual clus- tering problem, which can be useful for the niches＇ forming and searching. At last, a novel method that distributes samples to the corresponding cluster is proposed. Numerical results illustrate that this algorithm based on the density function and nichePSO could cluster unbalanced density datasets into the correct clusters auto- matically and accurately.
文摘This study analyzes drift phenomena of deterministic crowding and probabilistic crowding by using equivalence class model and expectation proportion equations. It is proved that the replacement errors of deterministic crowding cause the population converging to a single individual, thus resulting in premature stagnation or losing optional optima. And probabilistic crowding can maintain equilibrium multiple subpopulations as the population size is adequate large. An improved niching method using clustering crowding is proposed. By analyzing topology of fitness landscape using hill valley function and extending the search space for similarity analysis, clustering crowding determines the locality of search space more accurately, thus greatly decreasing replacement errors of crowding. The integration of deterministic and probabilistic replacement increases the capacity of both parallel local hill climbing and maintaining multiple subpopulations. The experimental results optimizing various multimodal functions show that,the performances of clustering crowding, such as the number of effective peaks maintained, average peak ratio and global optimum ratio are uniformly superior to those of the evolutionary algorithms using fitness sharing, simple deterministic crowding and probabilistic crowding.
基金supported mainly by grants from American Heart Association Scientist Development Grant ( 12SDG12050083 to G.D.)National Institute of Health ( R21HL102773,R21HD090680,R01HL118245 to G.D.)National Science Foundation ( CBET-1263455,CBET-1350240 to G.D.)
文摘Introduction Glioblastoma multiforme(GBM),a malignant brain tumor,is highly invasive and use brain microvessels to migrate and invade.Studying the perivascular invasion/migration of GBM may enable new possibilities in GBM therapy.However,the lack proper 3D study models that recapitulate GBM hallmarks restricts investigating cell-cell/cell-molecular interactions in tumor microenvironments.In this study,we created GBM-vascular niche models through 3D bioprinting [1-2] using patient-derived GBM cells with sternness(GSC:glioblastoma stem cells),vasculature endothelial cells(ECs),mural cells,and various hydrogels.Materials and methods Three GBM-vascular models were designed:Model A with large vessels and GBM spheroid;Model B with large-and micro-vessels,and GBM spheroid;Model C with large-and micro-vessels and scattered GBM cells.Large channels were created by sacrificial bioprinting.Microvessel network was formed through self-assembly of ECs(HUVEC or brain EC)and mural cells(fibroblast,pericytes,and/or astrocytes).Three GBM cell types were used in the study:SD02 and SD03 are GSCs;U87MG is a commercially-available GBM cell line.Collagen type I or fibrin hydrogel have been used as major scaffold materials.For drug treatment,Temozolomide in culture medium was perfused through large vasculatures in Model A.Results and discussion Three different GBM-vascular models were successfully fabricated and culture for 2-10.GSCs cultured in these models maintained sternness and heterogeneity during the long-term cultures.In Model A,GSCs actively invaded into the surrounding tissues(~Day26),initially regressed in response to the drug(~Day50),then developed therapeutic resistance and resumed aggressive invasion(~Day57).In Model B and C,three GBM types presented distinctive invasion patterns and EC-interactions.SD02 cells showed a spiky invasion pattern with elongated morphology.SD03 cells showed a more dispersed invasion pattern with many single cell migrations towards surrounding microvessels.U87MG cells showed a blunt invasion pattern,caused EC death in the spheroid form;however,the EC death was significantly reduced in the scattered single cell form.Conclusions In this study,we have created GBM-vascular niche models that can recapitulate various GBM characteristics such as cancer sternness,tumor type-specific invasion patterns,and drug responses with therapeutic resistance.Our models have a great potential in investigating patient-specific tumor behaviors under chemo-/radio-therapy conditions and consequentially helping to tailor personalized treatment strategy.The model platform is capable of modifying multiples variables including ECMs,cell types,vascular structures,and dynamic culture condition.Thus,it can be adapted to other biological systems and serve as a valuable tool for generating customized microenvironments.
