[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
Chinese and Japanese population of Chlamys farreri and their reciprocal hybrids were surveyed in isozyme variability at 13 loci by polyacrytamide gel electrophoresis (PAGE). Isozyme banding patterns indicated these hy...Chinese and Japanese population of Chlamys farreri and their reciprocal hybrids were surveyed in isozyme variability at 13 loci by polyacrytamide gel electrophoresis (PAGE). Isozyme banding patterns indicated these hybrids were diploid. Loci that were observed as being monomorphic in inbred populations of C. farreri were also found to be monomorphic in filial progeny; loci that observed to be polymorphic in parental type gen- erations were also polymorphic in hybrid generations. Differences existed among allelic frequency of the four types of cross. Within the reciprocal hybrids the expression of malic enzyme (ME) isozyme was sufficient to distinguishing individual hybrids because of the band, Rf=0.38. However, there were no noticeable variations among all the samples to differentiate one from another. Inbreeding was likely to be the main problem in aqua- culture. The introduction of new broodstock can improve the genetic diversity. Hybrid vigor has manifested to a certain extent in the present study.展开更多
Cryosurgery is an effective way of curing many diseases including tumors and cancers. It can be applied using a variety of systems and cryogens. Cheap, convenient, reliable equipment still needs to be developed so tha...Cryosurgery is an effective way of curing many diseases including tumors and cancers. It can be applied using a variety of systems and cryogens. Cheap, convenient, reliable equipment still needs to be developed so that cryotherapy may be accepted by surgeons and hospitals. This paper presents a cryosurgery apparatus that utilizes an auto-cascade refrigeration system. Refrigerant mixture R50/R23/R600a was selected as the working fluid. The mixture composition was altered to achieve lower temperatures and higher capacity. The lowest temperature at the cryoprobe could be as low as -100℃, and 8 W refrigeration capacity could be obtained at -80 ℃. An ice ball of 11.6 mm diameter could be formed when the cryoprobe was immersed in a water bath at 37 ℃.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 "973" Program (G1999012008) and "863" Program (2002AA626020).
文摘Chinese and Japanese population of Chlamys farreri and their reciprocal hybrids were surveyed in isozyme variability at 13 loci by polyacrytamide gel electrophoresis (PAGE). Isozyme banding patterns indicated these hybrids were diploid. Loci that were observed as being monomorphic in inbred populations of C. farreri were also found to be monomorphic in filial progeny; loci that observed to be polymorphic in parental type gen- erations were also polymorphic in hybrid generations. Differences existed among allelic frequency of the four types of cross. Within the reciprocal hybrids the expression of malic enzyme (ME) isozyme was sufficient to distinguishing individual hybrids because of the band, Rf=0.38. However, there were no noticeable variations among all the samples to differentiate one from another. Inbreeding was likely to be the main problem in aqua- culture. The introduction of new broodstock can improve the genetic diversity. Hybrid vigor has manifested to a certain extent in the present study.
基金Project (No.50606032) supported by the National Natural Science Foundation of China
文摘Cryosurgery is an effective way of curing many diseases including tumors and cancers. It can be applied using a variety of systems and cryogens. Cheap, convenient, reliable equipment still needs to be developed so that cryotherapy may be accepted by surgeons and hospitals. This paper presents a cryosurgery apparatus that utilizes an auto-cascade refrigeration system. Refrigerant mixture R50/R23/R600a was selected as the working fluid. The mixture composition was altered to achieve lower temperatures and higher capacity. The lowest temperature at the cryoprobe could be as low as -100℃, and 8 W refrigeration capacity could be obtained at -80 ℃. An ice ball of 11.6 mm diameter could be formed when the cryoprobe was immersed in a water bath at 37 ℃.
