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
同步讲解Section A1.—Did you see any cows?你看到奶牛了吗?—Yes,I did.I saw quite a lot.是的,我看到了许多奶牛。(1)quite a lot意为'许多;相当多',可以单独使用,也可跟of+可数/不可数名词。We drank quite a lot of wine...同步讲解Section A1.—Did you see any cows?你看到奶牛了吗?—Yes,I did.I saw quite a lot.是的,我看到了许多奶牛。(1)quite a lot意为'许多;相当多',可以单独使用,也可跟of+可数/不可数名词。We drank quite a lot of wine.我们喝了不少酒。I saw quite a lot of flowers.我看到了相当多的花。表示'相当多',还可以用quite a little和quite a few。quite a little后跟不可数名词;quite a few后跟可数名词。展开更多
本单元知识网络同步讲解Section A1.—Did you see any cows?你看到奶牛了吗?—Yes,I did.I saw quite a lot.是的,我看到了许多奶牛。(1)quite a lot意为'许多;相当多',可以单独使用,也可跟of+可数/不可数名词。We drank quite...本单元知识网络同步讲解Section A1.—Did you see any cows?你看到奶牛了吗?—Yes,I did.I saw quite a lot.是的,我看到了许多奶牛。(1)quite a lot意为'许多;相当多',可以单独使用,也可跟of+可数/不可数名词。We drank quite a lot of wine.我们喝了不少酒。I saw quite a lot of flowers.我看到了相当多的花。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.
文摘同步讲解Section A1.—Did you see any cows?你看到奶牛了吗?—Yes,I did.I saw quite a lot.是的,我看到了许多奶牛。(1)quite a lot意为'许多;相当多',可以单独使用,也可跟of+可数/不可数名词。We drank quite a lot of wine.我们喝了不少酒。I saw quite a lot of flowers.我看到了相当多的花。表示'相当多',还可以用quite a little和quite a few。quite a little后跟不可数名词;quite a few后跟可数名词。
文摘本单元知识网络同步讲解Section A1.—Did you see any cows?你看到奶牛了吗?—Yes,I did.I saw quite a lot.是的,我看到了许多奶牛。(1)quite a lot意为'许多;相当多',可以单独使用,也可跟of+可数/不可数名词。We drank quite a lot of wine.我们喝了不少酒。I saw quite a lot of flowers.我看到了相当多的花。
