OBJECTIVE The invasive sea lamprey(Petromyzon marinus)has devastated the ecosystem of the Laurentian Great Lakes.Application of pheromones to manipulate adult sea lamprey behavior is among the options considered for a...OBJECTIVE The invasive sea lamprey(Petromyzon marinus)has devastated the ecosystem of the Laurentian Great Lakes.Application of pheromones to manipulate adult sea lamprey behavior is among the options considered for alternative sea lamprey control techniques.The male sea lamprey sex pheromone is hypothesized to be possess multiple functions through actions of multiple components,some of which have yet to be characterized.Our objective is to isolate and characterize the bioactive components from water conditioned with sexually mature male sea lamprey.METHODS The water conditioned with sexually mature male sea lamprey was extracted by solid phase extraction and concentrated in vacuo.The compounds were isolated by liquid chromatography and elucidated by spectrometry and spectroscopy.Their biological activities were evaluated by electro-olfactogram recordings and two-choice maze behavioral assays.RESULTS Five novel bile salts,petromyzene A and B and petromyzone A-C,have been characterized.Petromyzene A and B featured either a unique,rearranged side chain or a rare cis-11,12-diol on the steroidal B-ring.Petromyzone A-C represented three novel highly oxidized sulfated bile alcohols possessing different hydroxylation,oxidation,and double bond patterns,which exemplify the chemical diversity of bile salts.These five bile salts were potent odorants that stimulated the adult sea lamprey olfactory epithelium in a concentration dependent manner and showed detection thresholds between 10–13mol·L^(-1) and 10^(–11)mol·L^(-1)(paired t-test,P<0.05).Experiments in the two-choice maze showed that all isolated compounds induced behavioral responses in ovulated females.CONCLUSION The five novel compounds are likely additional components of pheromones released by sexually mature male sea lamprey,and may provide useful behavioral manipulation tools to be implemented with the integrated management of the destructive and invasive sea lamprey in the Laurentian Great Lakes.展开更多
Ant colony optimization (ACO) algorithm was modified to optimize the global path. In order to simulate the real ant colonies, according to the foraging behavior of ant colonies and the characteristic of food, concepti...Ant colony optimization (ACO) algorithm was modified to optimize the global path. In order to simulate the real ant colonies, according to the foraging behavior of ant colonies and the characteristic of food, conceptions of neighboring area and smell area were presented. The former can ensure the diversity of paths and the latter ensures that each ant can reach the goal. Then the whole path was divided into three parts and ACO was used to search the second part path. When the three parts pathes were adjusted, the final path was found. The valid path and invalid path were defined to ensure the path valid. Finally, the strategies of the pheromone search were applied to search the optimum path. However, when only the pheromone was used to search the optimum path, ACO converges easily. In order to avoid this premature convergence, combining pheromone search and random search, a hybrid ant colony algorithm(HACO) was used to find the optimum path. The comparison between ACO and HACO shows that HACO can be used to find the shortest path.展开更多
In order to form an algorithm for distribution network routing,an automatic routing method of distribution network planning was proposed based on the shortest path.The problem of automatic routing was divided into two...In order to form an algorithm for distribution network routing,an automatic routing method of distribution network planning was proposed based on the shortest path.The problem of automatic routing was divided into two steps in the method:the first step was that the shortest paths along streets between substation and load points were found by the basic ant colony algorithm to form a preliminary radial distribution network,and the second step was that the result of the shortest path was used to initialize pheromone concentration and pheromone updating rules to generate globally optimal distribution network.Cases studies show that the proposed method is effective and can meet the planning requirements.It is verified that the proposed method has better solution and utility than planning method based on the ant colony algorithm.展开更多
In view of the serious reactive power loss in the rural network, improved ant colony optimization algorithm （ACOA） was used to optimize the reactive power compensation for the rural distribution system. In this stud...In view of the serious reactive power loss in the rural network, improved ant colony optimization algorithm （ACOA） was used to optimize the reactive power compensation for the rural distribution system. In this study, the traditional ACOA was improved in two aspects： one was the local search strategy, and the other was pheromone mutation and re-initialization strategies. The reactive power optimization for a county＇s distribution network showed that the improved ACOA was practicable.展开更多
文摘OBJECTIVE The invasive sea lamprey(Petromyzon marinus)has devastated the ecosystem of the Laurentian Great Lakes.Application of pheromones to manipulate adult sea lamprey behavior is among the options considered for alternative sea lamprey control techniques.The male sea lamprey sex pheromone is hypothesized to be possess multiple functions through actions of multiple components,some of which have yet to be characterized.Our objective is to isolate and characterize the bioactive components from water conditioned with sexually mature male sea lamprey.METHODS The water conditioned with sexually mature male sea lamprey was extracted by solid phase extraction and concentrated in vacuo.The compounds were isolated by liquid chromatography and elucidated by spectrometry and spectroscopy.Their biological activities were evaluated by electro-olfactogram recordings and two-choice maze behavioral assays.RESULTS Five novel bile salts,petromyzene A and B and petromyzone A-C,have been characterized.Petromyzene A and B featured either a unique,rearranged side chain or a rare cis-11,12-diol on the steroidal B-ring.Petromyzone A-C represented three novel highly oxidized sulfated bile alcohols possessing different hydroxylation,oxidation,and double bond patterns,which exemplify the chemical diversity of bile salts.These five bile salts were potent odorants that stimulated the adult sea lamprey olfactory epithelium in a concentration dependent manner and showed detection thresholds between 10–13mol·L^(-1) and 10^(–11)mol·L^(-1)(paired t-test,P<0.05).Experiments in the two-choice maze showed that all isolated compounds induced behavioral responses in ovulated females.CONCLUSION The five novel compounds are likely additional components of pheromones released by sexually mature male sea lamprey,and may provide useful behavioral manipulation tools to be implemented with the integrated management of the destructive and invasive sea lamprey in the Laurentian Great Lakes.
基金Projects(60234030, 60404021) supported by the National Natural Science Foundation of China
文摘Ant colony optimization (ACO) algorithm was modified to optimize the global path. In order to simulate the real ant colonies, according to the foraging behavior of ant colonies and the characteristic of food, conceptions of neighboring area and smell area were presented. The former can ensure the diversity of paths and the latter ensures that each ant can reach the goal. Then the whole path was divided into three parts and ACO was used to search the second part path. When the three parts pathes were adjusted, the final path was found. The valid path and invalid path were defined to ensure the path valid. Finally, the strategies of the pheromone search were applied to search the optimum path. However, when only the pheromone was used to search the optimum path, ACO converges easily. In order to avoid this premature convergence, combining pheromone search and random search, a hybrid ant colony algorithm(HACO) was used to find the optimum path. The comparison between ACO and HACO shows that HACO can be used to find the shortest path.
基金Project(2009CB219703) supported by the National Basic Research Program of ChinaProject(2011AA05A117) supported by the National High Technology Research and Development Program of China
文摘In order to form an algorithm for distribution network routing,an automatic routing method of distribution network planning was proposed based on the shortest path.The problem of automatic routing was divided into two steps in the method:the first step was that the shortest paths along streets between substation and load points were found by the basic ant colony algorithm to form a preliminary radial distribution network,and the second step was that the result of the shortest path was used to initialize pheromone concentration and pheromone updating rules to generate globally optimal distribution network.Cases studies show that the proposed method is effective and can meet the planning requirements.It is verified that the proposed method has better solution and utility than planning method based on the ant colony algorithm.
基金Supported by China Postdoctoral Science Foundation(20090460873)
文摘In view of the serious reactive power loss in the rural network, improved ant colony optimization algorithm （ACOA） was used to optimize the reactive power compensation for the rural distribution system. In this study, the traditional ACOA was improved in two aspects： one was the local search strategy, and the other was pheromone mutation and re-initialization strategies. The reactive power optimization for a county＇s distribution network showed that the improved ACOA was practicable.
