[Objective] This study aimed to observe and explore the behavior of Procambarus clarkii and Eriocheir sinensis in polyculture system. [Method] P. clarkii and E. sinensis with the same weight were used for the experime...[Objective] This study aimed to observe and explore the behavior of Procambarus clarkii and Eriocheir sinensis in polyculture system. [Method] P. clarkii and E. sinensis with the same weight were used for the experiment in a relatively small polyculture system. The agonistic behavior of P. clarkii and E. sinensis in the first 30 min of the initial encounter and the fighting results were observed and recorded; the approach-avoidance behavior of P. clarkii to bigger E. sinensis in a relatively large space （the ＂Y＂ maze） was observed and recorded. [Result] The re- sults showed that the times of first aggressions and approaches and the total times of active aggressions and approaches of P. clarkii in the initial period of polyculture experiment were all significantly more than E. sinensis （/：＇〈0.05）; after 30 d of poly- culture, P. clarkfi died in 30% of the groups while E. sinensis died in only 10% of the groups, and they coexisted in 60% of the groups. In the experiment of ap- proach-avoidance behavior of P. clarkii to bigger E. sinensis, with the increase of experiment times, the tendency of approach and avoidance of P. clarkii to the con- trol and E. sinensis became control-prefer （P〈0.05） from insignificantly different （P〉 0.05）, which indicated that the recognition ability of P. clarkii for E. sinensis was sig- nificantly improved, and the selection behavior of E. sinensis was obviously inhibited. [Conclusion] Presumably, polyculture of crayfishes and crabs can achieve better effi- ciency when under appropriate habitat conditions.展开更多
Stable carbon and nitrogen isotopes were used to investigate nutrient pathways and trophic relationships from the rice-crab system in Panjin, Liaoning Province, China. Values of 313C ranged from -27.38%±0.44%o to...Stable carbon and nitrogen isotopes were used to investigate nutrient pathways and trophic relationships from the rice-crab system in Panjin, Liaoning Province, China. Values of 313C ranged from -27.38%±0.44%o to -18.34%±0.26%o and δ^15N ranged from 1.10%o4-0.88%o to 9.33%±0.57%. Pseudorasbora parva （Stone moroko） had the highest δ^13C and 8tSN values. The lowest δ^13C values were obtained for the macrophytes and the lowest δ^15N value was found in sediments. Stable carbon and nitrogen isotopes were used to determine the contribution of different food items to the diets of crabs. The δ^13C results indicated that the Pseudorasbora parva made the greatest contribution to the diet of Eriocheir sinensis （Chinese mitten crab）, while the δ^15N results indicated that most food items contributed more than 10% to the diet of the crab. There were three trophic levels identified in the system （Levels 0-2）. The crab Eriocheir sinensis, fish Pseudorasbora parva and Misgurnus anguillicaudatus （Oriental weatherfish）, and the oligochaete Limnodrilus hoffmeisteri （Limnodrilus worm）, were at the second level, zooplankton were at the first level and suspended particulate matter and macrophytes were at trophic position 0.展开更多
This paper studies rotor spinning blended yam produced of spun silk and cashmere. Nine samples were spun, from three different opening rollers and different navels. According to the Uster test results of yam quality p...This paper studies rotor spinning blended yam produced of spun silk and cashmere. Nine samples were spun, from three different opening rollers and different navels. According to the Uster test results of yam quality properties, optimum selection is done by using analysis method of combining fuzzy decision-making and fuzzy pattern classification. Experimental plan is designed based on universal rotated experimental design, and the method of confined optimization is used to optimize the speed of opening roller, the speed of rotor and twist factor, according to the results of yam quality test by Uster.展开更多
Wool & silk blended fancy suiting is desinged. Through trial-production with silk sliver and Australian wool top, the spinning technology is investigated, and the relationship of spinning technology, blending rati...Wool & silk blended fancy suiting is desinged. Through trial-production with silk sliver and Australian wool top, the spinning technology is investigated, and the relationship of spinning technology, blending ratio and yarn construction is discussed.展开更多
基金Supported by National R&D Special Fund for Public Welfare Industry of China(201003070)National Natural Science Foundation of China (NSFC J0730641)~~
文摘[Objective] This study aimed to observe and explore the behavior of Procambarus clarkii and Eriocheir sinensis in polyculture system. [Method] P. clarkii and E. sinensis with the same weight were used for the experiment in a relatively small polyculture system. The agonistic behavior of P. clarkii and E. sinensis in the first 30 min of the initial encounter and the fighting results were observed and recorded; the approach-avoidance behavior of P. clarkii to bigger E. sinensis in a relatively large space （the ＂Y＂ maze） was observed and recorded. [Result] The re- sults showed that the times of first aggressions and approaches and the total times of active aggressions and approaches of P. clarkii in the initial period of polyculture experiment were all significantly more than E. sinensis （/：＇〈0.05）; after 30 d of poly- culture, P. clarkfi died in 30% of the groups while E. sinensis died in only 10% of the groups, and they coexisted in 60% of the groups. In the experiment of ap- proach-avoidance behavior of P. clarkii to bigger E. sinensis, with the increase of experiment times, the tendency of approach and avoidance of P. clarkii to the con- trol and E. sinensis became control-prefer （P〈0.05） from insignificantly different （P〉 0.05）, which indicated that the recognition ability of P. clarkii for E. sinensis was sig- nificantly improved, and the selection behavior of E. sinensis was obviously inhibited. [Conclusion] Presumably, polyculture of crayfishes and crabs can achieve better effi- ciency when under appropriate habitat conditions.
基金Supported by the National Special Research Fund for Non-Profit Sector(Agriculture)(No.201203O81-7)
文摘Stable carbon and nitrogen isotopes were used to investigate nutrient pathways and trophic relationships from the rice-crab system in Panjin, Liaoning Province, China. Values of 313C ranged from -27.38%±0.44%o to -18.34%±0.26%o and δ^15N ranged from 1.10%o4-0.88%o to 9.33%±0.57%. Pseudorasbora parva （Stone moroko） had the highest δ^13C and 8tSN values. The lowest δ^13C values were obtained for the macrophytes and the lowest δ^15N value was found in sediments. Stable carbon and nitrogen isotopes were used to determine the contribution of different food items to the diets of crabs. The δ^13C results indicated that the Pseudorasbora parva made the greatest contribution to the diet of Eriocheir sinensis （Chinese mitten crab）, while the δ^15N results indicated that most food items contributed more than 10% to the diet of the crab. There were three trophic levels identified in the system （Levels 0-2）. The crab Eriocheir sinensis, fish Pseudorasbora parva and Misgurnus anguillicaudatus （Oriental weatherfish）, and the oligochaete Limnodrilus hoffmeisteri （Limnodrilus worm）, were at the second level, zooplankton were at the first level and suspended particulate matter and macrophytes were at trophic position 0.
文摘This paper studies rotor spinning blended yam produced of spun silk and cashmere. Nine samples were spun, from three different opening rollers and different navels. According to the Uster test results of yam quality properties, optimum selection is done by using analysis method of combining fuzzy decision-making and fuzzy pattern classification. Experimental plan is designed based on universal rotated experimental design, and the method of confined optimization is used to optimize the speed of opening roller, the speed of rotor and twist factor, according to the results of yam quality test by Uster.
文摘Wool & silk blended fancy suiting is desinged. Through trial-production with silk sliver and Australian wool top, the spinning technology is investigated, and the relationship of spinning technology, blending ratio and yarn construction is discussed.
