1,815 results
Search Results
2. Dynamics of a linear source epidemic system with diffusion and media impact.
- Author
-
Li, Wenjie, Zhao, Weiran, Cao, Jinde, and Huang, Lihong
- Subjects
BASIC reproduction number ,EPIDEMICS ,LINEAR systems ,LYAPUNOV functions - Abstract
This paper studies an impact of media epidemic system with diffusion and linear source. We first derive the uniform bounds of solutions to impact on media reaction diffusion system. Then, the basic reproduction number is calculated and the threshold dynamics of impact media reaction diffusion system is also given and the Kuratowski measure κ of non-compactness is also considered. In addition, assume the spatial environment is homogeneous, it is shown that the unique endemic equilibrium of the system is global stability by constructing suitable Lyapunov function. Finally, we discuss the asymptotic profile of the system when the diffusion rate of the susceptible (infected) individuals for the system tends to zero or infinity. The main results show that the activities of infected individuals can only be at low risk, and then the virus eventually will be extinct, that is, to control the entry of viruses from abroad and increase the detection of domestic viruses. Finally, some numerical simulations are worked out to confirm the results obtained in this paper. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Stationary distribution of a stochastic three species predator–prey model with anti-predator behavior
- Author
-
Kang, Ming, Zhang, Xiang, Geng, Fengjie, and Ma, Zhaohai
- Published
- 2024
- Full Text
- View/download PDF
4. R0 May Not Tell Us Everything: Transient Disease Dynamics of Some SIR Models Over Patchy Environments
- Author
-
Li, Ao and Zou, Xingfu
- Published
- 2024
- Full Text
- View/download PDF
5. Understanding death risks of Covid-19 under media awareness strategy: a stochastic approach
- Author
-
Kai Wang, Regragui Taki, M. Lakhal, M. El Fatini, and M. El Khalifi
- Subjects
Algebra and Number Theory ,Coronavirus disease 2019 ,Coronavirus disease 2019 (COVID-19) ,SARS-CoV-2 ,Computer science ,Applied Mathematics ,Social distance ,Control (management) ,Intervention effect ,Media coverage ,92B05 ,93E15 ,Original Research Paper ,Stochastic epidemic model ,93C10 ,Econometrics ,General rate incidence ,Epidemic disease ,Geometry and Topology ,Uniqueness ,Functional analysis (psychology) ,Analysis - Abstract
The coronavirus disease 2019 (COVID-19) is rapidly spreading in the world and the mortality rate is getting higher and higher. Due to the outbreak of such epidemic disease, many countries imposed stricter measures among which is social distancing and enforced isolation. The present study tries to establish a realistic model to characterize the dynamics of COVID-19 and explicitly parameterize the intervention effects of control measures. In so doing, it takes into account stochastic perturbation and investigates the effects of media coverage on the transmission dynamics. This paper seeks to study the existence and uniqueness of the global positive solution to the proposed model and establish conditions for extinction and persistence in mean of the disease. Numerical simulations are presented to show the theoretical results obtained from this study.
- Published
- 2021
6. Spreading Speed and Profile for the Lotka–Volterra Competition Model with Two Free Boundaries.
- Author
-
Wang, Zhiguo, Qin, Qian, and Wu, Jianhua
- Abstract
This paper is concerned with the spreading behavior of a two-species strong-weak competition system with two free boundaries. The model may describe how a strong competing species invades into the habitat of a native weak competing species. The asymptotic spreading speed of invading fronts has been determined by making use of semi-wave systems in Du et al. (J Math Pures Appl 107:253–287, 2017). Here we give a sharp estimate for the asymptotic spreading speed of invading fronts. Moreover, we prove that the solution of the free boundary problem evolves eventually into a semi-wave solution when the spreading happens, while the solution of the free boundary problem exponentially converges to a semi-trivial solution of such system when the vanishing happens. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
7. Competitive Exclusion and Coexistence in a Stoichiometric Chemostat Model.
- Author
-
Ji, Juping and Wang, Hao
- Abstract
In this paper, we incorporate stoichiometry into a competition model in chemostat culture. We first discuss the dynamics of this stoichiometric chemostat model for single algae species. We obtain the uniform persistence and find that an increase of phosphorus input or a slow dilution rate facilitates the algal persistence. Then, we consider a stoichiometric chemostat model in which two species competing for single nutrient, investigate how stoichiometry, dilution rate and concentration of phosphorus input affect the result of competition between algae species. Competitive exclusion and coexistence of two competing algae species are explored by discussing the existence, local stability of all feasible equilibria. Previous studies suggested that competitive exclusion holds in general chemostat models with two species competing for one limiting nutrient. Our theoretical and numerical results demonstrate that stoichiometry brings the coexistence of two competing algae species. Moreover, under low phosphorus input or fast dilution rate, competitive exclusion still holds. High phosphorus input or slow dilution rate facilitates the coexistence of multiple species. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
8. The effects of three release strategies on Wolbachia infection frequency in mosquito populations.
- Author
-
Shi, Yantao, Yu, Jianshe, and Li, Jia
- Subjects
MOSQUITOES ,WOLBACHIA ,MOSQUITO-borne diseases ,MOSQUITO control ,INFECTION ,DENGUE - Abstract
In control of wild mosquitoes to fight mosquito-borne diseases, release of mosquitoes with Wolbachia is one of the effective biological control methods. There are three release strategies, namely releasing both Wolbachia-infected females and males, only Wolbachia-infected females and only Wolbachia-infected males. All these three strategies have been confirmed to be capable of speeding up the Wolbachia persistence in mosquito populations. In this paper, we investigate how supplementary releases affect the Wolbachia spread dynamics in mosquito populations. Our aim is to compare the effectiveness among these three release strategies. We obtain theoretical results and provide numerical simulations that show that the first two strategies are more effective than the last strategy. For the first two strategies, the former strategy is either less effective than the latter strategy in each generation, or more effective than the latter strategy in previous generations, and then becomes less effective in late generations. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
9. The robustness of phylogenetic diversity indices to extinctions.
- Author
-
Manson, Kerry
- Abstract
Phylogenetic diversity indices provide a formal way to apportion evolutionary history amongst living species. Understanding the properties of these measures is key to determining their applicability in conservation biology settings. In this work, we investigate some questions posed in a recent paper by Fischer et al. (Syst Biol 72(3):606–615, 2023). In that paper, it is shown that under certain extinction scenarios, the ranking of the surviving species by their Fair Proportion index scores may be the complete reverse of their ranking beforehand. Our main results here show that this behaviour extends to a large class of phylogenetic diversity indices, including the Equal-Splits index. We also provide a necessary condition for reversals of Fair Proportion rankings to occur on phylogenetic trees whose edge lengths obey the ultrametric constraint. Specific examples of rooted phylogenetic trees displaying these behaviours are given and the impact of our results on the use of phylogenetic diversity indices more generally is discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
10. Mathematical modeling of the spread of the coronavirus under strict social restrictions
- Author
-
Khalid Dib, Kalyanasundaram Madhu, Mo'tassem Al-arydah, and Hailay Weldegiorgis Berhe
- Subjects
Download ,General Mathematics ,media_common.quotation_subject ,coronavirus ,92Bxx ,Permission ,Unit (housing) ,COVID‐19 ,37Nxx ,Special Issue Paper ,Econometrics ,Quality (business) ,Mathematics ,media_common ,Notice ,Special Issue Papers ,Social distance ,Warranty ,General Engineering ,social distancing ,92b05 ,37n25 ,parameter estimations ,Order (business) ,variable transmission rate ,mathematical model - Abstract
We formulate a simple susceptible‐infectious‐recovery (SIR) model to describe the spread of the coronavirus under strict social restrictions. The transmission rate in this model is exponentially decreasing with time. We find a formula for basic reproduction function and estimate the maximum number of daily infected individuals. We fit the model to induced death data in Italy, United States, Germany, France, India, Spain, and China over the period from the first reported death to August 7, 2020. We notice that the model has excellent fit to the disease death data in these countries. We estimate the model's parameters in each of these countries with 95% confidence intervals. We order the strength of social restrictions in these countries using the exponential rate. We estimate the time needed to reduce the basic reproduction function to one unit and use it to order the quality of social restrictions in these countries. The social restriction in China was the strictest and the most effective and in India was the weakest and the least effective. Policy‐makers may apply the Chinese successful social restriction experiment and avoid the Indian unsuccessful one. [ FROM AUTHOR] Copyright of Mathematical Methods in the Applied Sciences is the property of John Wiley & Sons, Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)
- Published
- 2021
11. The effect of public health awareness and behaviors on the transmission dynamics of syphilis in Northwest China, 2006-2018, based on a multiple-stages mathematical model
- Author
-
Yu Zhao, Weichen Liu, Wenjun Jing, and Ning Ma
- Subjects
medicine.medical_specialty ,Syphilis model ,Primary Syphilis ,Epidemiology of syphilis ,Infectious and parasitic diseases ,RC109-216 ,37H10 ,92B05 ,Control strategy ,Environmental health ,medicine ,Transmission (medicine) ,Applied Mathematics ,Health Policy ,Public health ,medicine.disease ,Basic reproduction number ,Infectious Diseases ,34F05 ,Data fitting ,Health education ,Syphilis ,Psychology ,Epidemic model ,Sensitivity analysis ,60J70 ,Research Paper - Abstract
Syphilis, a sexually transmitted infectious disease caused by the bacterium treponema pallidum, has re-emerged as a global public health issue with an estimated 12 million people infected each year. Understanding the impacts of health awareness and behaviors on transmission dynamics of syphilis can help to establish optimal control strategy in different regions. In this paper, we develop a multiple-stage SIRS epidemic model taking into account the public health awareness and behaviors of syphilis. First, the basic reproduction number R 0 is obtained, which determines the global dynamics behaviors of the model. We derive the necessary conditions for implementing optimal control and the corresponding optimal solution for mitigation syphilis by using Pontryagin's Maximum Principle. Based on the data of syphilis in Ningxia from 2006 to 2018, the parameterizations and model calibration are carried out. The fitting results are in good agreement with the data. Moreover, sensitivity analysis shows that the public awareness induced protective behaviors Ce, compliance of condom-induced preventability e and treatment for the primary syphilis m1 play an important role in mitigating the risk of syphilis outbreaks. These results can help us gain insights into the epidemiology of syphilis and provide guidance for the public health authorities to implement health education programs.
- Published
- 2021
12. Nonlinear dynamics of a time-delayed epidemic model with two explicit aware classes, saturated incidences, and treatment
- Author
-
Nilam, Abhishek Kumar, and Kanica Goel
- Subjects
Nonlinear incidences and treatment rates ,Aerospace Engineering ,Ocean Engineering ,Type (model theory) ,92B05 ,01 natural sciences ,Stability (probability) ,34D20 ,symbols.namesake ,Bifurcations ,37M05 ,Stability theory ,0103 physical sciences ,Numerical simulations ,Applied mathematics ,Full and partial awareness ,Electrical and Electronic Engineering ,010301 acoustics ,Bifurcation ,Mathematics ,Hopf bifurcation ,Original Paper ,Applied Mathematics ,Mechanical Engineering ,Nonlinear system ,Control and Systems Engineering ,symbols ,Epidemic model ,Basic reproduction number ,Stability ,Time delay - Abstract
Whenever a disease emerges, awareness in susceptibles prompts them to take preventive measures, which influence individuals’ behaviors. Therefore, we present and analyze a time-delayed epidemic model in which class of susceptible individuals is divided into three subclasses: unaware susceptibles, fully aware susceptibles, and partially aware susceptibles to the disease, respectively, which emphasizes to consider three explicit incidences. The saturated type of incidence rates and treatment rate of infectives are deliberated herein. The mathematical analysis shows that the model has two equilibria: disease-free and endemic. We derive the basic reproduction number \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$R_0$$\end{document}R0 of the model and study the stability behavior of the model at both disease-free and endemic equilibria. Through analysis, it is demonstrated that the disease-free equilibrium is locally asymptotically stable when \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$R_01$$\end{document}R0>1, and linearly neutrally stable when \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$R_0=1$$\end{document}R0=1 for the time delay \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varrho >0$$\end{document}ϱ>0. Further, an undelayed epidemic model is studied when \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$R_0=1$$\end{document}R0=1, which reveals that the model exhibits forward and backward bifurcations under specific conditions, which also has important implications in the study of disease transmission dynamics. Moreover, we investigate the stability behavior of the endemic equilibrium and show that Hopf bifurcation occurs near endemic equilibrium when we choose time delay as a bifurcation parameter. Lastly, numerical simulations are performed in support of our analytical results.
- Published
- 2020
13. Sharp asymptotic profile of the solution to a West Nile virus model with free boundary.
- Author
-
Wang, Zhiguo, Nie, Hua, and Du, Yihong
- Subjects
WEST Nile virus ,MOSQUITO control - Abstract
We consider the long-time behaviour of a West Nile virus (WNv) model consisting of a reaction–diffusion system with free boundaries. Such a model describes the spreading of WNv with the free boundary representing the expanding front of the infected region, which is a time-dependent interval $[g(t), h(t)]$ in the model (Lin and Zhu, Spatial spreading model and dynamics of West Nile virus in birds and mosquitoes with free boundary. J. Math. Biol. 75, 1381–1409, 2017). The asymptotic spreading speed of the front has been determined in Wang et al. (Spreading speed for a West Nile virus model with free boundary. J. Math. Biol. 79, 433–466, 2019) by making use of the associated semi-wave solution, namely $\lim _{t\to \infty } h(t)/t=\lim _{t\to \infty }[\!-g(t)/t]=c_\nu$ , with $c_\nu$ the speed of the semi-wave solution. In this paper, by employing new techniques, we significantly improve the estimate in Wang et al. (Spreading speed for a West Nile virus model with free boundary. J. Math. Biol. 79, 433–466, 2019): we show that $h(t)-c_\nu t$ and $g(t)+c_\nu t$ converge to some constants as $t\to \infty$ , and the solution of the model converges to the semi-wave solution. The results also apply to a wide class of analogous Ross–MacDonold epidemic models. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
14. Global existence and steady states of the density-suppressed motility model with strong Allee effect.
- Author
-
Song, Cui, Wang, Zhi-Cheng, and Feng, Zhaosheng
- Subjects
- *
ALLEE effect , *COMPUTER simulation , *EQUILIBRIUM , *CLASSICAL solutions (Mathematics) - Abstract
This paper considers a density-suppressed motility model with a strong Allee effect under the homogeneous Neumman boundary condition. We first establish the global existence of bounded classical solutions to a parabolic–parabolic system over an |$N $| -dimensional |$\mathbf{(N\le 3)}$| bounded domain |$\varOmega $| , as well as the global existence of bounded classical solutions to a parabolic–elliptic system over the multidimensional bounded domain |$\varOmega $| with smooth boundary. We then investigate the linear stability at the positive equilibria for the full parabolic case and parabolic–elliptic case, respectively, and find the influence of Allee effect on the local stability of the equilibria. By treating the Allee effect as a bifurcation parameter, we focus on the one-dimensional stationary problem and obtain the existence of non-constant positive steady states, which corresponds to small perturbations from the constant equilibrium |$(1,1)$|. Furthermore, we present some properties through theoretical analysis on pitchfork type and turning direction of the local bifurcations. The stability results provide a stable wave mode selection mechanism for the model considered in this paper. Finally, numerical simulations are performed to demonstrate our theoretical results. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
15. Mathematical modelling to assess the impact of stress on temperature-dependent sex determination in teleost fish.
- Author
-
Byun, Jong Hyuk, Jung, Il Hyo, and Jeong, Yong Dam
- Abstract
Temperature-dependent sex determination (TSD) is an environmental phenomenon in which the temperature during the embryonic or larval stages influences the determination of sex. It is mainly observed in teleost fish, where high water temperatures can induce a female-to-male transition. The exact mechanism by which environmental changes affect TSD is poorly understood, but cortisol, a stress hormone, is considered a potential factor. Although excessive secretion of cortisol is known to cause side effects, it can lead to a switch in sex hormones, potentially resulting in TSD. In this paper, we investigate the mechanism of TSD in teleost fish. To assess the impact of stress caused by changes in water temperature on TSD, we established a mathematical model for hormonal dynamics that incorporates cortisol. First, we conducted a stability analysis to qualitatively examine the sex determination. The temperature dependence was modeled using the Eyring–Polanyi equation, and we examined corresponding hormonal changes with water temperature. Furthermore, we theoretically investigated the role of a cortisol inhibitor in preventing side effects during TSD. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
16. Incorporating age and delay into models for biophysical systems
- Author
-
KhudaBukhsh, Wasiur R., Kang, Hye-Won, Kenah, Eben, and Rempala, Grzegorz A.
- Subjects
Quantitative Biology - Populations and Evolution ,92B05 - Abstract
In many biological systems, chemical reactions or changes in a physical state are assumed to occur instantaneously. For describing the dynamics of those systems, Markov models that require exponentially distributed inter-event times have been used widely. However, some biophysical processes such as gene transcription and translation are known to have a significant gap between the initiation and the completion of the processes, which renders the usual assumption of exponential distribution untenable. In this paper, we consider relaxing this assumption by incorporating age-dependent random time delays into the system dynamics. We do so by constructing a measure-valued Markov process on a more abstract state space, which allows us to keep track of the "ages" of molecules participating in a chemical reaction. We study the large-volume limit of such age-structured systems. We show that, when appropriately scaled, the stochastic system can be approximated by a system of Partial Differential Equations (PDEs) in the large-volume limit, as opposed to Ordinary Differential Equations (ODEs) in the classical theory. We show how the limiting PDE system can be used for the purpose of further model reductions and for devising efficient simulation algorithms. In order to describe the ideas, we use a simple transcription process as a running example. We, however, note that the methods developed in this paper apply to a wide class of biophysical systems., Comment: 21 pages, 4 figures. Under review for publication
- Published
- 2020
17. Modeling the Dynamics of COVID-19 in Nigeria
- Author
-
Matthew O. Adewole, Farah Aini Abdullah, Akindele A. Onifade, Funmilayo Kasali, and Ahmad Izani Md. Ismail
- Subjects
Original Paper ,Mathematical optimization ,Pontryagin’s maximum principle ,34C20 ,Coronavirus disease 2019 (COVID-19) ,Computer science ,Applied Mathematics ,030231 tropical medicine ,COVID-19 ,Prevention guidelines ,Mass testing ,92B05 ,Optimal control ,Stability (probability) ,Pontryagin's minimum principle ,03 medical and health sciences ,Computational Mathematics ,0302 clinical medicine ,Maximum principle ,Contact tracing ,92D30 ,Key (cryptography) ,030212 general & internal medicine ,Sensitivity (control systems) ,Basic reproduction number - Abstract
To understand the dynamics of COVID-19 in Nigeria, a mathematical model which incorporates the key compartments and parameters regarding COVID-19 in Nigeria is formulated. The basic reproduction number is obtained which is then used to analyze the stability of the disease-free equilibrium solution of the model. The model is calibrated using data obtained from Nigeria Centre for Disease Control and key parameters of the model are estimated. Sensitivity analysis is carried out to investigate the influence of the parameters in curtailing the disease. Using Pontryagin’s maximum principle, time-dependent intervention strategies are optimized in order to suppress the transmission of the virus. Numerical simulations are then used to explore various optimal control solutions involving single and multiple controls. Our results suggest that strict intervention effort is required for quick suppression of the disease.
- Published
- 2021
18. Dynamics of neural system under the influence of a magnetic flux
- Author
-
De Angelis, Monica
- Published
- 2024
- Full Text
- View/download PDF
19. Spontaneous Infection and Periodic Evolving of Domain in a Diffusive SIS Epidemic Model
- Author
-
Wen, Qiang, Ren, Guo-qiang, and Liu, Bin
- Published
- 2024
- Full Text
- View/download PDF
20. Predicting the stability of profiling signals of small RNAs
- Author
-
Li, Qiuyun and Riehl, Manda
- Subjects
Quantitative Biology - Biomolecules ,92B05 - Abstract
Profiling is a process that finds similarities between different RNA secondary structures by extracting signals from the Boltzmann sampling. The reproducibility of profiling can be identified by the standard deviation of number of features among Boltzmann samples. We found a strong relationship between the frequency of each helix class and its standard deviation of the frequency upon repeated Boltzmann sampling. We developed a perturbation technique to predict the stability of these featured helix classes without the need for repeated Boltzmann sampling, with accuracy between 84% and 94%, depending on the type of RNA. Our technique only requires 0.2% of the computation time compared to one profiling process., Comment: 14 pages
- Published
- 2024
21. Assessing Syphilis transmission among MSM population incorporating low and high-risk infection: a modeling study
- Author
-
Chukwu, Chidozie Williams, Chazuka, Zviiteyi, Safdar, Salman, Febriana, Iffatricia Haura, and Aldila, Dipo
- Published
- 2024
- Full Text
- View/download PDF
22. A nonautonomous model for the interaction between a size-structured consumer and an unstructured resource
- Author
-
Ni, Zhuxin and Huang, Qihua
- Published
- 2024
- Full Text
- View/download PDF
23. Stationary distribution of a stochastic epidemic model with distributed delay under regime switching.
- Author
-
Chen, Shengshuang, Guo, Yingxin, and Zhang, Chuan
- Abstract
This paper aims to analyze the dynamic behavior of a novel stochastic epidemic model (SEM) that incorporates distributed delay and time switching. We prove the existence and uniqueness of a global positive solution and establish the presence of ergodic stationary distribution (ESD) through the construction of appropriate Lyapunov functions. The threshold R 0 S derived from our analysis plays a vital role in this procedure. Additionally, we conduct computer simulations to validate our theoretical discoveries, demonstrating that the incorporation of white noise can induce random fluctuations in the system variables under time switching. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
24. Wolbachia spread dynamics in mosquito populations in cyclic environments.
- Author
-
Zheng, Bo and Yu, Jianshe
- Subjects
WOLBACHIA ,MOSQUITOES ,AEDES aegypti ,MOSQUITO-borne diseases ,COMPUTER simulation ,LOGICAL prediction - Abstract
In this paper, we establish a discrete model with periodic parameters to depict the Wolbachia spread dynamics in mosquito populations in cyclic environments. This work modifies the models established in the existing literature that did not take into account the variation of parameters with environmental periodic changes due to seasonality and other factors. When the parameters in our model are constants, it has been extensively studied and widely used. We present a conjecture about the existence of at most two periodic solutions worthy of further study, and show that the conjecture is true for the special case of 2-periodic parameters. Numerical simulations are also provided to illustrate the occurrence of periodic phenomena. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
25. A novel mechanism measurement of predator interference in predator–prey models.
- Author
-
Alebraheem, Jawdat and Abu-Hassan, Yahya
- Abstract
A characteristic of ecosystems is the existence of manifold of independencies which are highly complex. Various mathematical models have made considerable contributions in gaining a better understanding of the predator–prey interactions. The main components of any predator–prey models are, firstly, how the different population classes grow and secondly, how the prey and predator interacts. In this paper, the two populations’ growth rates obey the logistic law and the carrying capacity of the predator depends on the available number of prey are considered. Our aim is to clarify the relationship between models and Holling types functional and numerical responses in order to gain insights into predator interferences and to answer an important question how competition is carried out. We consider a predator–prey model and a two-predator one-prey model to explain the idea. The novel approach is explained for the mechanism measurement of predator interference through depending on numerical response. Our approach gives good correspondence between an important real data and computer simulations. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
26. Effective dose fractionation schemes of radiotherapy for prostate cancer
- Author
-
Alvarez, Jose, Storey, Kathleen M., Kannan, Pavitra, and Cho, Heyrim
- Subjects
Physics - Medical Physics ,Quantitative Biology - Populations and Evolution ,92B05 - Abstract
Radiation therapy has remained as one of the main cancer treatment modalities and a highly cost-effective single modality treatment of cancer care. Typical regimens for fractionated external beam radiotherapy comprise a constant dose administered on weekdays, and no radiation on weekends. However, every patient has a tumor with distinct properties depending on intra-tumor heterogeneity, aggressiveness, and interactive properties with other cells that may make it more resistant or sensitive to radiation treatment. Accordingly, the concept of personalized cancer treatment is emerging to specialize each patient treatment case to the unique properties of the tumor. In this paper, we examine adaptive radiation treatment strategies for heterogeneous tumors using a dynamical system model that consists of radiation-resistant and parental cell populations with unique interactive properties. We study different adaptive dosage strategies for PC3 and DU145 prostate cancer cell lines. We show that stronger doses of radiation given in longer time intervals, while keeping the overall dosage the same, reduce final tumor volume by more than half in PC3 cell lines, but by only five percent in DU145 cell lines. In addition, we tested an adaptive dosing schedule by administering a stronger dosage on Friday to compensate for the treatment-off period during the weekend, which was effective in decreasing the final tumor volume of both cell lines. This result creates interesting possibilities for new radiotherapy strategies at clinics that cannot provide treatment on weekends. Finally, we propose a dosage plan incorporating our findings., Comment: 15 pages, 9 figures
- Published
- 2021
- Full Text
- View/download PDF
27. Symmetry-Breaking in Plant Stems
- Author
-
Harper, Larry and Huey, Greg
- Subjects
Quantitative Biology - Quantitative Methods ,Quantitative Biology - Populations and Evolution ,92B05 - Abstract
The purpose of this paper is to present a model of a phenomenon of plant stem morphogenesis observed by Cesar Gomez-Campo in 1970. We consider a simplified model of auxin dynamics in plant stems, showing that, after creation of the original primordium, it can represent random, distichous and spiral phyllotaxis (leaf arrangement) just by varying one parameter, the rate of diffusion. The same analysis extends to the $n$-jugate case where $n$ primordia are initiated at each plastochrone. Having validated the model, we consider how it can give rise to the Gomez-Campo phenomenon, showing how a stem with spiral phyllotaxis can produce branches of the same or opposite chirality. And finally, how the relationship can change from discordant to concordant over the course of a growing season., Comment: 27 pages, 17 figures
- Published
- 2021
28. Hopf Bifurcation Analysis of a Predator–Prey Model with Prey Refuge and Fear Effect Under Non-diffusion and Diffusion.
- Author
-
Zhang, Haisu and Qi, Haokun
- Abstract
In this paper, we propose a predator–prey model with prey refuge and fear effect under non-diffusion and diffusion. For the non-diffusion ODE model, we first analyze the existence and stability of equilibria. Then, the existence of transcritical bifurcation, Hopf bifurcation and limit cycle is discussed, respectively. We find that when the cost of minimum fear η is taken as the bifurcation parameter, it not only influence the occurrence of Hopf bifurcation but also alters its direction. For diffusion predator–prey model under homogeneous Neumann boundary conditions, we observe that the Turing instability does not occur, but the Hopf bifurcation will manifest near the interior equilibrium. By considering η as the bifurcation parameter, the direction and stability of spatially homogeneous periodic orbits are established. At last, the validity of the theoretical analysis are verified by a series of numerical simulations. The results indicate that prey refuge and fear effect play an key role in the stability of populations. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
29. Modelling and analysis of periodic impulsive releases of the Nilaparvata lugens infected with wStri-Wolbachia.
- Author
-
Dai, Xiangjun, Quan, Qi, and Jiao, Jianjun
- Subjects
NILAPARVATA lugens ,NUMERICAL analysis - Abstract
In this paper, we formulate a population suppression model and a population replacement model with periodic impulsive releases of Nilaparvata lugens infected with wStri. The conditions for the stability of wild- $ N.\,lugens $ N. l u g e n s -eradication periodic solution of two systems are obtained by applying the Floquet theorem and comparison theorem. And the sufficient conditions for the persistence in the mean of wild $ N.\,lugens $ N. l u g e n s are also given. In addition, the sufficient conditions for the extinction and persistence of the wild $ N.\,lugens $ N. l u g e n s in the subsystem without wLug are also obtained. Finally, we give numerical analysis which shows that increasing the release amount or decreasing the release period are beneficial for controlling the wild $ N.\,lugens $ N. l u g e n s , and the efficiency of population replacement strategy in controlling wild populations is higher than that of population suppression strategy under the same release conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
30. Dynamical behaviour of an intraguild predator–prey model with prey refuge and hunting cooperation.
- Author
-
Meng, Xin-You and Feng, Yan
- Subjects
LOTKA-Volterra equations ,HOPF bifurcations ,ORDINARY differential equations ,PARTIAL differential equations ,TOPOLOGICAL degree ,HUNTING ,COOPERATION - Abstract
An intraguild predator–prey model including prey refuge and hunting cooperation is investigated in this paper. First, for the corresponding ordinary differential equation model, the existence and stability of all equilibria are given, and the existence of Hopf bifurcation, direction and stability of bifurcating periodic solutions are investigated. Then, for partial differential equation model, the diffusion-driven Turing instability is obtained. What is more, the existence and non-existence of the non-constant positive steady state of the reaction–diffusion model are established by the Leray–Schauder degree theory and some priori estimates. Next, some numerical simulations are performed to support analytical results. The results showed that prey refuge can change the stability of model and even have a stabilizing effect on this model, meanwhile the hunting cooperation can make such model without diffusion unstable, but make such model with diffusion stable. Lastly, a brief conclusion is concluded in the last section. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
31. Vanishing-Spreading Dichotomy in a Two-Species Chemotaxis Competition System with a Free Boundary.
- Author
-
Bao, Lianzhang and Shen, Wenxian
- Subjects
CHEMOTAXIS ,INTRODUCED species - Abstract
Predicting the evolution of expanding population is critical to control biological threats such as invasive species and virus explosion. In this paper, we consider a two species chemotaxis system of parabolic-parabolic-elliptic type with Lotka–Volterra type competition terms and a free boundary. Such a model with a free boundary describes the spreading of new or invasive species subject to the influence of some chemical substances in an environment with a free boundary representing the spreading front. We first find conditions on the parameters which guarantee the global existence and boundedness of classical solutions with nonnegative initial functions. Next, we investigate vanishing-spreading dichotomy scenarios for positive solutions. It is shown that the vanishing-spreading dichotomy in the generalized sense always occurs; that the vanishing spreading dichotomy in the strong sense occurs when the competition between two species is weak-weak competition; and that the vanishing spreading dichotomy in the weak sense occurs when the competition between two species is weak-strong competition. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
32. A generalized stochastic SIR epidemic model with vaccination rules.
- Author
-
Ma, Zhihui, Qi, Ting, and Li, Xiaohua
- Subjects
EPIDEMICS ,VACCINATION ,STOCHASTIC systems ,PREVENTIVE medicine ,COMPUTER simulation - Abstract
In this paper, a generalized stochastic SIR epidemic model with vaccination rules is presented and the threshold behavior of the proposed epidemic model is investigated. Firstly, the stability of the equilibrium of the deterministic system is considered and the corresponding conditions are obtained. Secondly, the threshold of a stochastic SIR system for the extinction and the permanence in mean of epidemic disease are investigated. The results show that a larger stochastic disturbance can cause infections diseases to go to extinction. However, for a relatively small stochastic disturbance, the evolutionary dynamics of the epidemic diseases are overwhelmingly depend on the incidence function. This implies that the stochastic disturbance and the incidence function play an important role in diseases control. To test the theoretical results, a series of numerical simulations of these cases with respect to different noise disturbance coefficients are conducted. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
33. Hopf Bifurcation Analysis of a Delayed Fractional BAM Neural Network Model with Incommensurate Orders.
- Author
-
Li, Bingbing, Liao, Maoxin, Xu, Changjin, and Li, Weinan
- Subjects
HOPF bifurcations - Abstract
In this paper, a six-neuron incommensurate fractional order BAM neural network model with multi-delays is considered. We demonstrate that the equilibrium point of the system loses its stability and Hopf bifurcation emerges when the delay passes through a critical value. And the relationship between the critical delay of Hopf bifurcation and size of fractional orders is found. Finally, some numerical simulations are given to verify the validity of the theoretical results. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
34. Mathematical modeling of mitigation of carbon dioxide emissions by controlling the population pressure.
- Author
-
Verma, Maitri, Verma, Alok Kumar, and Gautam, Cherie
- Abstract
The anthropogenic carbon dioxide (C O 2) emission from the burning of fossil fuels is the prime cause behind the menace of global warming. Over the past few decades, fossil fuel consumption has increased drastically to fulfill the energy demand of the growing population and economy. The population pressure has not only contributed to the increase in fossil fuel consumption but also accelerated the deforestation for industrial, agricultural, and infrastructure expansion. This paper presents a nonlinear mathematical model to study the effect of an increase in fossil fuel use and deforestation due to population pressure on atmospheric carbon dioxide concentration. Further, the effect of economic efforts applied to reduce the population pressure over the control of atmospheric C O 2 levels is explored. The model analysis shows that an increase in the fossil fuel consumption rate causes an increase in the equilibrium level of carbon dioxide. Further, it is found that an increase in the deforestation rate coefficient has a destabilizing effect on the stability of positive state of the system. If the deforestation rate crosses a critical threshold, the positive state of the system loses stability and the periodic solutions arise via Hopf-bifurcation. It is shown that at high deforestation rates, an increase in the implementation rate of economic efforts applied to reduce the population pressure may cause reduction in the amplitude of periodic oscillations. The periodic oscillations may disappear if the implementation rate of economic effort increased beyond a critical threshold and the concentration of carbon dioxide gets stabilized. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
35. Numerical treatment of optimal control theory applied to malaria transmission dynamic model.
- Author
-
Bakare, E. A. and Hoskova-Mayerova, S.
- Subjects
INSECTICIDE resistance ,OPTIMAL control theory ,MALARIA ,PONTRYAGIN'S minimum principle ,DYNAMIC models - Abstract
Malaria is preventable and curable but critical disease caused by parasites that are transmitted to people through the bites of female Anopheles mosquitoes. There were an estimated 228 million cases of malaria globally and its mortality remained at 405,000 in 2018. There are many models that have been developed but the aim of this paper is to analyse the potential impact of multiple current interventions in communities with limited resources. The authors in their previous work, developed a population-based model of malaria transmission dynamics to investigate the effectiveness of five different interventions. This model captured both the human and the mosquito compartments and considered 5 control interventions. Namely it was: educational campaigns to mobilise people for diagnostic test and treatment and to sleep under bed nets; treatment through mass drug administration; indoor residual spraying with insecticide to reduce malaria transmission; insecticide treated net to reduce morbidity; and regular destruction of mosquito breeding sites to reduce the number of new mosquito and bites/contact at dusks and dawn. In the present work we carried out basic mathematical analysis of the model, simulate the different scenarios developed and optimise the control interventions with optimal control. The potential of the control interventions to reduce transmission within 120 days was observed. The numerical experiments showed that the optimal strategy to effectively control malaria was through the combinations of controls in the models. The developed malaria model predicted the reduction, control and/or elimination of malaria threats through incorporating multiple control interventions. Therefore, multiple control measures should be adopted for malaria but in areas of limited resources, we can make use of strategy E and others in places where there are more resources. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
36. Qualitative analysis of a stock-effort parabolic model incorporating marine reserve.
- Author
-
Moussaoui, A.
- Subjects
MARINE parks & reserves ,ELLIPTIC operators ,SIZE of fishes ,EIGENVALUES - Abstract
A stock-effort dynamical model of a fishery with spatial structure is considered to assess the impacts of reserve size on fishing catch. We study the existence, uniqueness and global character of the solutions. It is shown that when the cost of fishing effort is less than the principal eigenvalue for an elliptic operator defined on a bounded domain corresponding to the fishing zone, then the fishery is viable, while in the opposite case, the fishery is not viable and fishing effort disappears. For both cases, the existence of stable solutions is studied. We perform some numerical simulations to illustrate our results in this paper and give a brief concluding remark. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
37. Global Dynamics of a Kawasaki Disease Vascular Endothelial Cell Injury Model with Backward Bifurcation and Hopf Bifurcation
- Author
-
Guo, Ke and Ma, Wan-biao
- Published
- 2024
- Full Text
- View/download PDF
38. Topological and geometric analysis of cell states in single-cell transcriptomic data
- Author
-
Huynh, Tram and Cang, Zixuan
- Subjects
Quantitative Biology - Quantitative Methods ,Quantitative Biology - Genomics ,92B05 - Abstract
Single-cell RNA sequencing (scRNA-seq) enables dissecting cellular heterogeneity in tissues, resulting in numerous biological discoveries. Various computational methods have been devised to delineate cell types by clustering scRNA-seq data where the clusters are often annotated using prior knowledge of marker genes. In addition to identifying pure cell types, several methods have been developed to identify cells undergoing state transitions which often rely on prior clustering results. Present computational approaches predominantly investigate the local and first-order structures of scRNA-seq data using graph representations, while scRNA-seq data frequently displays complex high-dimensional structures. Here, we present a tool, scGeom for exploiting the multiscale and multidimensional structures in scRNA-seq data by inspecting the geometry via graph curvature and topology via persistent homology of both cell networks and gene networks. We demonstrate the utility of these structural features for reflecting biological properties and functions in several applications where we show that curvatures and topological signatures of cell and gene networks can help indicate transition cells and developmental potency of cells. We additionally illustrate that the structural characteristics can improve the classification of cell types.
- Published
- 2023
39. A mathematician's view of the unreasonable ineffectiveness of mathematics in biology
- Author
-
Borovik, Alexandre
- Subjects
Mathematics - History and Overview ,92B05 - Abstract
This paper discusses, from a mathematician's point of view, the thesis formulated by Israel Gelfand, one of the greatest mathematicians of the 20th century, and one of the pioneers of mathematical biology: "There is only one thing which is more unreasonable than the unreasonable effectiveness of mathematics in physics, and this is the unreasonable ineffectiveness of mathematics in biology."
- Published
- 2021
40. Dynamical analysis of a stochastic maize streak virus epidemic model with logarithmic Ornstein–Uhlenbeck process.
- Author
-
Liu, Qun
- Abstract
To describe the transmission dynamics of maize streak virus infection, in the paper, we first formulate a stochastic maize streak virus infection model, in which the stochastic fluctuations are depicted by a logarithmic Ornstein–Uhlenbeck process. This approach is reasonable to simulate the random impacts of main parameters both from the biological significance and the mathematical perspective. Then we investigate the detailed dynamics of the stochastic system, including the existence and uniqueness of the global solution, the existence of a stationary distribution, the exponential extinction of the infected maize and infected leafhopper vector. Especially, by solving the five-dimensional algebraic equations corresponding to the stochastic system, we obtain the specific expression of the probability density function near the quasi-endemic equilibrium of the stochastic system, which provides valuable insights into the stationary distribution. Finally, the model is discretized using the Milstein higher-order numerical method to illustrate our theoretical results numerically. Our findings provide a groundwork for better methods of preventing the spread of this type of virus. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. Dynamics of a multigroup stochastic SIQR epidemic model.
- Author
-
Lamei, Sanaz and Akbari, Mozhgan
- Subjects
- *
BASIC reproduction number , *EPIDEMICS - Abstract
In this paper, we consider a multigroup stochastic SIQR epidemic model with varying total population size. After proving the existence and uniqueness of the global solution to the system, we developed sufficient conditions for the existence of an stationary ergodic distribution of the positive solutions. Then we gave sufficient conditions for extinction of the diseases which is based on the basic reproduction number in its corresponding deterministic system. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
42. The role of Allee effects for Gaussian and Lévy dispersals in an environmental niche.
- Author
-
Dipierro, Serena, Proietti Lippi, Edoardo, and Valdinoci, Enrico
- Abstract
In the study of biological populations, the Allee effect detects a critical density below which the population is severely endangered and at risk of extinction. This effect supersedes the classical logistic model, in which low densities are favorable due to lack of competition, and includes situations related to deficit of genetic pools, inbreeding depression, mate limitations, unavailability of collaborative strategies due to lack of conspecifics, etc. The goal of this paper is to provide a detailed mathematical analysis of the Allee effect. After recalling the ordinary differential equation related to the Allee effect, we will consider the situation of a diffusive population. The dispersal of this population is quite general and can include the classical Brownian motion, as well as a Lévy flight pattern, and also a “mixed” situation in which some individuals perform classical random walks and others adopt Lévy flights (which is also a case observed in nature). We study the existence and nonexistence of stationary solutions, which are an indication of the survival chance of a population at the equilibrium. We also analyze the associated evolution problem, in view of monotonicity in time of the total population, energy consideration, and long-time asymptotics. Furthermore, we also consider the case of an “inverse” Allee effect, in which low density populations may access additional benefits. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. Analysis and numerical simulation of a reaction–diffusion mathematical model of atherosclerosis
- Author
-
Mukherjee, Debasmita and Mukherjee, Avishek
- Published
- 2023
- Full Text
- View/download PDF
44. Impact of a cost functional on the optimal control and the cost-effectiveness: control of a spreading infection as a case study
- Author
-
Saldaña, Fernando, Camacho-Gutiérrez, José Ariel, and Korobeinikov, Andrei
- Subjects
Mathematics - Optimization and Control ,92B05 - Abstract
In applications of the optimal control theory to problems in medicine and biology, the dependency of the objective functional on the control itself is often a matter of controversy. In this paper, we explore the impact of the dependency using reasonably simple \emph{SIR} and \emph{SEIRS} epidemic models. To qualitatively compare the outcomes for different objective functionals, we apply the cost-effectiveness analysis. Our result shows that, at least for the comparatively inexpensive controls, the variation of the power at the controls in a biologically feasible range does not significantly affect the forms of the optimal controls and the corresponding optimal state solutions. Moreover, the costs and effectiveness are affected even less. At the same time, the dependency of the cost on the state variables can be very significant., Comment: 22 pages
- Published
- 2020
45. When optimal is not the best: cost effectiveness analysis for HPV epidemic models
- Author
-
Saldaña, Fernando, Camacho-Gutíerrez, José Ariel, Barradas, Ignacio, and Korobeinikov, Andrei
- Subjects
Mathematics - Optimization and Control ,92B05 - Abstract
This paper aims to evaluate the potential cost-effectiveness of healthcare interventions against human papillomavirus (HPV). For this, we consider a two-sex epidemic model for the transmission dynamics of HPV which includes screening, vaccination of adolescent boys and girls, and vaccination of sexually active adults. We first propose public health policies using constant control parameters and develop a cost-effectiveness analysis (CEA) to identify which intervention delivers the best effectiveness for the money invested. Secondly, we consider time-dependent control parameters and formulate an optimal control problem to obtain time-dependent versions of the interventions. As in the case of constant control parameters, we perform a CEA to investigate the cost-effectiveness of the time-dependent control interventions. Our findings suggest that females' vaccination, including adolescent girls and adult women, is the most cost-effective strategy. We also compare constant against the time-dependent healthcare interventions which are optimal in the sense that they minimize the objective functional of the optimal control problem. The results indicate that time-dependent controls are not always more cost-effective than constant controls., Comment: 22 pages, 5 figures
- Published
- 2020
46. Study of dose-dependent combination immunotherapy using engineered T cells and IL-2 in cervical cancer
- Author
-
Cho, Heyrim, Wang, Zuping, and Levy, Doron
- Subjects
Quantitative Biology - Populations and Evolution ,Quantitative Biology - Tissues and Organs ,92B05 - Abstract
Adoptive T cell based immunotherapy is gaining significant traction in cancer treatment. Despite its limited success, so far, in treating solid cancers, it is increasingly successful, demonstrating to have a broader therapeutic potential. In this paper we develop a mathematical model to study the efficacy of engineered T cell receptor (TCR) T cell therapy targeting the E7 antigen in cervical cancer cell lines. We consider a dynamical system that follows the population of cancer cells, TCR T cells, and IL-2. We demonstrate that there exists a TCR T cell dosage window for a successful cancer elimination that can be expressed in terms of the initial tumor size. We obtain the TCR T cell dose for two cervical cancer cell lines: 4050 and CaSki. Finally, a combination therapy of TCR T cell and IL-2 treatment is studied. We show that certain treatment protocols can improve therapy responses in the 4050 cell line, but not in the CaSki cell line., Comment: 8 pages, 7 figures
- Published
- 2020
- Full Text
- View/download PDF
47. Optimal protein production by a synthetic microbial consortium: coexistence, distribution of labor, and syntrophy.
- Author
-
Martínez, Carlos, Cinquemani, Eugenio, Jong, Hidde de, and Gouzé, Jean-Luc
- Abstract
The bacterium E. coli is widely used to produce recombinant proteins such as growth hormone and insulin. One inconvenience with E. coli cultures is the secretion of acetate through overflow metabolism. Acetate inhibits cell growth and represents a carbon diversion, which results in several negative effects on protein production. One way to overcome this problem is the use of a synthetic consortium of two different E. coli strains, one producing recombinant proteins and one reducing the acetate concentration. In this paper, we study a mathematical model of such a synthetic community in a chemostat where both strains are allowed to produce recombinant proteins. We give necessary and sufficient conditions for the existence of a coexistence equilibrium and show that it is unique. Based on this equilibrium, we define a multi-objective optimization problem for the maximization of two important bioprocess performance metrics, process yield and productivity. Solving numerically this problem, we find the best available trade-offs between the metrics. Under optimal operation of the mixed community, both strains must produce the protein of interest, and not only one (distribution instead of division of labor). Moreover, in this regime acetate secretion by one strain is necessary for the survival of the other (syntrophy). The results thus illustrate how complex multi-level dynamics shape the optimal production of recombinant proteins by synthetic microbial consortia. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
48. Competitive dual-strain SIS epidemiological models with awareness programs in heterogeneous networks: two modeling approaches.
- Author
-
Sun, Mengfeng and Fu, Xinchu
- Abstract
Epidemic diseases and media campaigns are closely associated with each other. Considering most epidemics have multiple pathogenic strains, in this paper, we take the lead in proposing two multi-strain SIS epidemic models in heterogeneous networks incorporating awareness programs due to media. For the first model, we assume that the transmission rates for strain 1 and strain 2 depend on the level of awareness campaigns. For the second one, we further suppose that awareness divides susceptible population into two different subclasses. After defining the basic reproductive numbers for the whole model and each strain, we obtain the analytical conditions that determine the extinction, coexistence and absolute dominance of two strains. Moreover, we also formulate its optimal control problem and identify an optimal implementation pair of awareness campaigns using optimal control theory. Given the complexity of the second model, we use the numerical simulations to visualize its different types of dynamical behaviors. Through theoretical and numerical analysis of these two models, we discover some new phenomena. For example, during the persistence analysis of the first model, we find that the characteristic polynomials of two boundary equilibria may have a pair of pure imaginary roots, implying that Hopf bifurcation and periodic solutions may appear. Most strikingly, multistability occurs in the second model and the growth rate of awareness programs (triggered by the infection prevalence) has a multistage impact on the final size of two strains. The numerical results suggest that the spread of a two-strain epidemic can be controlled (even be eradicated) by taking the measures of enhancing awareness transmission, reducing memory fading of aware individuals and ensuring high-level influx and rapid growth of awareness programs appropriately. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
49. Dynamical Analysis of Nonautonomous Trophic Cascade Chemostat Model with Regime Switching and Nonlinear Perturbations in a Polluted Environment.
- Author
-
Li, Ya-jie, Qi, Hao-kun, Chang, Zheng-bo, and Meng, Xin-zhu
- Abstract
This paper investigates the stochastic dynamics of trophic cascade chemostat model perturbed by regime switching, Gaussian white noise and impulsive toxicant input. For the system with only white noise interference, sufficient conditions for stochastically ultimate boundedness and stochastically permanence are obtained, and we demonstrate that the stochastic system has at least one nontrivial positive periodic solution. For the system with Markov regime switching, sufficient conditions for extinction of the microorganisms are established. Then we prove the system is ergodic and has a stationary distribution. The results show that both impulsive toxins input and stochastic noise have great effects on the survival and extinction of the microorganisms. Finally, a series of numerical simulations are presented to illustrate the theoretical analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
50. The Lost Art of Mathematical Modelling
- Author
-
Gyllingberg, Linnéa, Birhane, Abeba, and Sumpter, David J. T.
- Subjects
Quantitative Biology - Other Quantitative Biology ,Computer Science - Machine Learning ,Nonlinear Sciences - Adaptation and Self-Organizing Systems ,Physics - Biological Physics ,92B05 - Abstract
We provide a critique of mathematical biology in light of rapid developments in modern machine learning. We argue that out of the three modelling activities -- (1) formulating models; (2) analysing models; and (3) fitting or comparing models to data -- inherent to mathematical biology, researchers currently focus too much on activity (2) at the cost of (1). This trend, we propose, can be reversed by realising that any given biological phenomena can be modelled in an infinite number of different ways, through the adoption of an open/pluralistic approach. We explain the open approach using fish locomotion as a case study and illustrate some of the pitfalls -- universalism, creating models of models, etc. -- that hinder mathematical biology. We then ask how we might rediscover a lost art: that of creative mathematical modelling. This article is dedicated to the memory of Edmund Crampin.
- Published
- 2023
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.