The dynamical characters of a theoretical anti-tumor model under immune surveillance subjected to a pure multiplicative noise are investigated. The effects of pure multiplicative noise on the stationary probability di...The dynamical characters of a theoretical anti-tumor model under immune surveillance subjected to a pure multiplicative noise are investigated. The effects of pure multiplicative noise on the stationary probability distribution （SPD） and the mean first passage time （MFPT） are analysed based on the approximate Fokker-Planck equation of the system in detail. For the anti-tumor model, with the multiplieative noise intensity D increasing, the tumor population move towards to extinction and the extinction rate can be enhanced. Numerical simulations are carried out to check the approximate theoretical results. Reasonably good agreement is obtained.展开更多
[Objective] The aim was to study the current living situation of Yangtze finless porpoise, and explore the prediction of the number of Yangtze finless porpoise in next few years. [Method] Modified Leslie Model and Sil...[Objective] The aim was to study the current living situation of Yangtze finless porpoise, and explore the prediction of the number of Yangtze finless porpoise in next few years. [Method] Modified Leslie Model and Siler's Model was applied to estimate the number of Yangtze finless porpoise. [Result] Using the model,Yangtze finless porpoise will extinct in nearly 20 years. [Conclusion] The study provides a cautionary warning of the conservation of the freshwater cetacean species.展开更多
基金Supported by the Natural Science Foundation of China under Grant No.10865006the Science Foundation of the Education Bureau of Shaanxi Province under Grant No.09JK331the Science Foundation of Baoji University of Science and Arts of China under Grant No.Zk0725
文摘The dynamical characters of a theoretical anti-tumor model under immune surveillance subjected to a pure multiplicative noise are investigated. The effects of pure multiplicative noise on the stationary probability distribution （SPD） and the mean first passage time （MFPT） are analysed based on the approximate Fokker-Planck equation of the system in detail. For the anti-tumor model, with the multiplieative noise intensity D increasing, the tumor population move towards to extinction and the extinction rate can be enhanced. Numerical simulations are carried out to check the approximate theoretical results. Reasonably good agreement is obtained.
文摘[Objective] The aim was to study the current living situation of Yangtze finless porpoise, and explore the prediction of the number of Yangtze finless porpoise in next few years. [Method] Modified Leslie Model and Siler's Model was applied to estimate the number of Yangtze finless porpoise. [Result] Using the model,Yangtze finless porpoise will extinct in nearly 20 years. [Conclusion] The study provides a cautionary warning of the conservation of the freshwater cetacean species.
