A stochastic epidemic model with two age groups is established in this study,in which the susceptible(S),the exposed(E),the infected(I),the hospitalized(H)and the recovered(R)are involved within the total population,t...A stochastic epidemic model with two age groups is established in this study,in which the susceptible(S),the exposed(E),the infected(I),the hospitalized(H)and the recovered(R)are involved within the total population,the aging rates between two age groups are set to be constant.The existence-and-uniqueness of global positive solution is firstly showed.Then,by constructing several appropriate Lyapunov functions and using the high-dimensional Itô’s formula,the sufficient conditions for the stochastic extinction and stochastic persistence of the exposed individuals and the infected individuals are obtained.The stochastic extinction indicator and the stochastic persistence indicator are less-valued expressions compared with the basic reproduction number.Meanwhile,the main results of this study are modified into multi-age groups.Furthermore,by using the surveillance data for Fujian Provincial Center for Disease Control and Prevention,Fuzhou COVID-19 epidemic is chosen to carry out the numerical simulations,which show that the age group of the population plays the vital role when studying infectious diseases.展开更多
AIM:To investigate the impact of chronic fatigue on disease-related worries in inflammatory bowel disease (IBD) and the potential multicolinearity between subjective questionnaires.METHODS:Patients in remission or wit...AIM:To investigate the impact of chronic fatigue on disease-related worries in inflammatory bowel disease (IBD) and the potential multicolinearity between subjective questionnaires.METHODS:Patients in remission or with mild-tomoderate disease activity completed the fatigue questionnaire (FQ),the rating form of IBD patient concerns (RFIPC),the Short-Form 36 (SF-36),and IBD questionnaire (N-IBDQ).In addition,clinical and epidemiological data were obtained.RESULTS:In total,140 patients were included;of which 92 were diagnosed with ulcerative colitis and 48 with Crohn's disease.The mean age of patients with chronic fatigue was 44.2 years (SD=15.8) and for non-fatigued patients was 44.7 years (SD=16.0).Chronic fatigued patients had clinically significantly increased levels of disease-related worries,as measured by Cohen's d effect size.Worries about having an ostomy bag,loss of bowel control,and energy levels were most prominent in both chronic fatigued and non-chronic fatigued IBD patients.Variance inflation factor (VIF) and tolerance indicated that there were no problematic multicolinearity among the FQ,RFIPC,SF-36 and N-IBDQ responses (VIF < 5 and tolerance > 2).CONCLUSION:Chronic fatigue is associated with increased levels of disease-related worries and concerns in IBD.Increased levels of worries were also associated with impaired health-related quality of life.展开更多
We study the application of a pulse vaccination strategy to eradicate the slowly progressing diseases that have infectiousness in latent period. We derive the condition in which eradication solution is a global attrac...We study the application of a pulse vaccination strategy to eradicate the slowly progressing diseases that have infectiousness in latent period. We derive the condition in which eradication solution is a global attractor, this condition depends on pulse vaccination proportion p. We also obtain the condition of the global asymptotic stability of the solution. The condition shows that large enough pulse vaccination proportion and relatively small interpulse time lead to the eradication of the diseases. Moreover the results of the theoretical study might be instructive to the epidemiology of HIV.展开更多
An infection-age structured epidemic model with a nonlinear incidence rate is investigated.We formulate the model as an abstract non-densely defined Cauchy problem and derive the condition which guarantees the existen...An infection-age structured epidemic model with a nonlinear incidence rate is investigated.We formulate the model as an abstract non-densely defined Cauchy problem and derive the condition which guarantees the existence and uniqueness for positive age-dependent equilibrium of the model.By analyzing the associated characteristic transcendental equation and applying the normal form theory presented recently for non-densely defined semilinear equations,we show that the SIR(susceptible-infected-recovered)epidemic model undergoes Zero-Hopf bifurcation at the positive equilibrium which is the main result of this paper.展开更多
A heroin model with nonlinear incidence rate and age structure is investigated. The basic reproduction number is determined whether or not a heroin epidemic breaks out. By employing the Lyapunov functionals, the drug-...A heroin model with nonlinear incidence rate and age structure is investigated. The basic reproduction number is determined whether or not a heroin epidemic breaks out. By employing the Lyapunov functionals, the drug-free equilibrium is globally asymptotically stable if R0 ≤1; while the drug spread equilibrium is also globally asymptotically stable if R0≤ 1. Our results imply that improving detected rates and drawing up the efficient prevention play more important role than increasing the treatment for drug users.展开更多
We present an epidemic model which can incorporate essential biological detail as well as the intrinsic demographic stochastieity of the epidemic process, yet is very simple, enabling rapid generation of a large numbe...We present an epidemic model which can incorporate essential biological detail as well as the intrinsic demographic stochastieity of the epidemic process, yet is very simple, enabling rapid generation of a large number of simulations, A deterministic version of the model is also derived, in the limit of infinitely large populations, and a final-size formula for the deterministic model is proved. A key advantage of the model proposed is that it is possible to write down an explicit likelihood functions for it, which enables a systematic procedure for fitting parameters to real incidence data, using maximum likelihood.展开更多
基金Supported by National Natural Science Foundation of China(61911530398,12231012)Consultancy Project by the Chinese Academy of Engineering(2022-JB-06,2023-JB-12)+3 种基金the Natural Science Foundation of Fujian Province of China(2021J01621)Special Projects of the Central Government Guiding Local Science and Technology Development(2021L3018)Royal Society of Edinburgh(RSE1832)Engineering and Physical Sciences Research Council(EP/W522521/1).
文摘A stochastic epidemic model with two age groups is established in this study,in which the susceptible(S),the exposed(E),the infected(I),the hospitalized(H)and the recovered(R)are involved within the total population,the aging rates between two age groups are set to be constant.The existence-and-uniqueness of global positive solution is firstly showed.Then,by constructing several appropriate Lyapunov functions and using the high-dimensional Itô’s formula,the sufficient conditions for the stochastic extinction and stochastic persistence of the exposed individuals and the infected individuals are obtained.The stochastic extinction indicator and the stochastic persistence indicator are less-valued expressions compared with the basic reproduction number.Meanwhile,the main results of this study are modified into multi-age groups.Furthermore,by using the surveillance data for Fujian Provincial Center for Disease Control and Prevention,Fuzhou COVID-19 epidemic is chosen to carry out the numerical simulations,which show that the age group of the population plays the vital role when studying infectious diseases.
基金Supported by Oslo University Hospital Akerstfold HospitalTrustFerring Pharmaceuticals
文摘AIM:To investigate the impact of chronic fatigue on disease-related worries in inflammatory bowel disease (IBD) and the potential multicolinearity between subjective questionnaires.METHODS:Patients in remission or with mild-tomoderate disease activity completed the fatigue questionnaire (FQ),the rating form of IBD patient concerns (RFIPC),the Short-Form 36 (SF-36),and IBD questionnaire (N-IBDQ).In addition,clinical and epidemiological data were obtained.RESULTS:In total,140 patients were included;of which 92 were diagnosed with ulcerative colitis and 48 with Crohn's disease.The mean age of patients with chronic fatigue was 44.2 years (SD=15.8) and for non-fatigued patients was 44.7 years (SD=16.0).Chronic fatigued patients had clinically significantly increased levels of disease-related worries,as measured by Cohen's d effect size.Worries about having an ostomy bag,loss of bowel control,and energy levels were most prominent in both chronic fatigued and non-chronic fatigued IBD patients.Variance inflation factor (VIF) and tolerance indicated that there were no problematic multicolinearity among the FQ,RFIPC,SF-36 and N-IBDQ responses (VIF < 5 and tolerance > 2).CONCLUSION:Chronic fatigue is associated with increased levels of disease-related worries and concerns in IBD.Increased levels of worries were also associated with impaired health-related quality of life.
基金The research is supported by the National Science Foundation of Henan Province(No. 0611051800).
文摘We study the application of a pulse vaccination strategy to eradicate the slowly progressing diseases that have infectiousness in latent period. We derive the condition in which eradication solution is a global attractor, this condition depends on pulse vaccination proportion p. We also obtain the condition of the global asymptotic stability of the solution. The condition shows that large enough pulse vaccination proportion and relatively small interpulse time lead to the eradication of the diseases. Moreover the results of the theoretical study might be instructive to the epidemiology of HIV.
基金supported by National Natural Science Foundation of China (Grant Nos. 11471044 and 11371058)the Fundamental Research Funds for the Central Universities
文摘An infection-age structured epidemic model with a nonlinear incidence rate is investigated.We formulate the model as an abstract non-densely defined Cauchy problem and derive the condition which guarantees the existence and uniqueness for positive age-dependent equilibrium of the model.By analyzing the associated characteristic transcendental equation and applying the normal form theory presented recently for non-densely defined semilinear equations,we show that the SIR(susceptible-infected-recovered)epidemic model undergoes Zero-Hopf bifurcation at the positive equilibrium which is the main result of this paper.
文摘A heroin model with nonlinear incidence rate and age structure is investigated. The basic reproduction number is determined whether or not a heroin epidemic breaks out. By employing the Lyapunov functionals, the drug-free equilibrium is globally asymptotically stable if R0 ≤1; while the drug spread equilibrium is also globally asymptotically stable if R0≤ 1. Our results imply that improving detected rates and drawing up the efficient prevention play more important role than increasing the treatment for drug users.
文摘We present an epidemic model which can incorporate essential biological detail as well as the intrinsic demographic stochastieity of the epidemic process, yet is very simple, enabling rapid generation of a large number of simulations, A deterministic version of the model is also derived, in the limit of infinitely large populations, and a final-size formula for the deterministic model is proved. A key advantage of the model proposed is that it is possible to write down an explicit likelihood functions for it, which enables a systematic procedure for fitting parameters to real incidence data, using maximum likelihood.
