This paper considers an SIRS epidemic model that incorporates constant immigrati on rate, a general population size dependent contact rate and proportional tran sfer rate from the infective class to susceptible class...This paper considers an SIRS epidemic model that incorporates constant immigrati on rate, a general population size dependent contact rate and proportional tran sfer rate from the infective class to susceptible class.A threshold parameter σ is identified. If σ≤1, the disease free equilibrium is globally stab le. If σ>1, a unique endemic equilibrium is locally asymptotically stable. For two important special cases of mass action incidence and standard incidence, global stability of the endemic equilibrium is proved provided the threshold is larger than unity. Some previous results are extended and improved.展开更多
Haihui 818 is a new restorer line by cross breeding with Hua 23 S and Huahui 8131.Good plant type,high tillering ability,fine grain quality,strong restoring ability and high yield were shown in hybrid production.After...Haihui 818 is a new restorer line by cross breeding with Hua 23 S and Huahui 8131.Good plant type,high tillering ability,fine grain quality,strong restoring ability and high yield were shown in hybrid production.After artificial inoculation and field stress and molecular market-assisted selection,the results showed that rice-blast resistance genes Pi1,BB resistance genes Xa7,and brown planthopper resistance genes Bph3,Bph14 and Bph15 were pyramided together.Among its hybrids,Bo II You 818(Bo II A/Haihui 818)was approved for commercial production by Hainan Provincial Crop Variety Approval Committee in 2015.展开更多
基金Supported by the Science and Technology Foundation of Zhejiang University(1 0 70 0 0 - 54430 1 )
文摘This paper considers an SIRS epidemic model that incorporates constant immigrati on rate, a general population size dependent contact rate and proportional tran sfer rate from the infective class to susceptible class.A threshold parameter σ is identified. If σ≤1, the disease free equilibrium is globally stab le. If σ>1, a unique endemic equilibrium is locally asymptotically stable. For two important special cases of mass action incidence and standard incidence, global stability of the endemic equilibrium is proved provided the threshold is larger than unity. Some previous results are extended and improved.
基金Earmarked Fund for China Agriculture Research System(CARS-01-89)Crop Genetics and Breeding-Tropical Characteristic Rice Genetic Breeding(JBKYYNF-2020-03)Identification and Development of Tropical Rice Germplasm Resources in Southeast Asia(KJCX-2020-11)。
文摘Haihui 818 is a new restorer line by cross breeding with Hua 23 S and Huahui 8131.Good plant type,high tillering ability,fine grain quality,strong restoring ability and high yield were shown in hybrid production.After artificial inoculation and field stress and molecular market-assisted selection,the results showed that rice-blast resistance genes Pi1,BB resistance genes Xa7,and brown planthopper resistance genes Bph3,Bph14 and Bph15 were pyramided together.Among its hybrids,Bo II You 818(Bo II A/Haihui 818)was approved for commercial production by Hainan Provincial Crop Variety Approval Committee in 2015.
