Journal of Biological Dynamics最新文献

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Parameter identifiability and optimal control of an SARS-CoV-2 model early in the pandemic 疫情早期严重急性呼吸系统综合征冠状病毒2型模型的参数可识别性和最优控制

IF 2.8 4区数学 Q3 ECOLOGY

Journal of Biological Dynamics

Pub Date : 2022-05-30 DOI: 10.1080/17513758.2022.2078899

N. Tuncer, A. Timsina, M. Nuño, G. Chowell, M. Martcheva

We fit an SARS-CoV-2 model to US data of COVID-19 cases and deaths. We conclude that the model is not structurally identifiable. We make the model identifiable by prefixing some of the parameters from external information. Practical identifiability of the model through Monte Carlo simulations reveals that two of the parameters may not be practically identifiable. With thus identified parameters, we set up an optimal control problem with social distancing and isolation as control variables. We investigate two scenarios: the controls are applied for the entire duration and the controls are applied only for the period of time. Our results show that if the controls are applied early in the epidemic, the reduction in the infected classes is at least an order of magnitude higher compared to when controls are applied with 2-week delay. Further, removing the controls before the pandemic ends leads to rebound of the infected classes.

我们将SARS-CoV-2模型与美国新冠肺炎病例和死亡数据进行了拟合。我们得出的结论是，该模型在结构上是不可识别的。我们通过在外部信息中预先添加一些参数来识别模型。通过蒙特卡洛模拟，模型的实际可识别性表明，其中两个参数可能无法实际识别。利用这样确定的参数，我们建立了一个以社交距离和隔离为控制变量的最优控制问题。我们研究了两种情况：控制应用于整个持续时间，控制仅应用于一段时间。我们的结果表明，如果在疫情早期应用控制措施，与延迟2周应用控制措施相比，感染类别的减少至少高出一个数量级。此外，在疫情结束前取消控制会导致受感染阶层的反弹。

引用次数: 16

Viability of Pentadesma in reduced habitat ecosystems within two climatic regions with fruit harvesting 五连丝在两个气候区内有水果收获的减少栖息地生态系统中的生存能力

IF 2.8 4区数学 Q3 ECOLOGY

Journal of Biological Dynamics

Pub Date : 2022-05-09 DOI: 10.1080/17513758.2022.2071489

M. Leite, B. Chen-Charpentier, F. Agusto, O. Gaoue, N. Hritonenko

Habitat loss and harvesting of non-timber forest products (NTFPs) significantly affect the population dynamics. In this paper, we propose a general mathematical modelling approach incorporating the impact of habitat size reduction and non-lethal harvesting of NTFP on population dynamics. The model framework integrates experimental data of Pentadesma butyracea in Benin. This framework allows us to determine the rational non-lethal harvesting level and habitat size to ensure the stability of the plant ecosystem, and to study the impacts of distinct levels of humidity. We suggest non-lethal harvesting policies that maximize the economic benefit for local populations.

栖息地的丧失和非木材林产品的采伐对种群动态产生了重大影响。在本文中，我们提出了一种通用的数学建模方法，该方法结合了栖息地规模减少和非致命性NTFP收获对种群动态的影响。该模型框架整合了贝宁的五连糖丁酸的实验数据。该框架使我们能够确定合理的非致命收获水平和栖息地大小，以确保植物生态系统的稳定性，并研究不同湿度水平的影响。我们建议采取非致命性收割政策，最大限度地提高当地人口的经济效益。

引用次数: 1

Dynamics of autotroph–mixotroph interactions with the intraguild predation structure 自养-混合养生物与鱼体内捕食结构相互作用的动力学

IF 2.8 4区数学 Q3 ECOLOGY

Journal of Biological Dynamics

Pub Date : 2022-04-25 DOI: 10.1080/17513758.2022.2066729

Ming Chen, Jimin Zhang, Satlykova Ejegul

A mathematical model with the intraguild predation structure is proposed to describe the interactions of autotrophs and mixotrophs containing light and nutrients in a well-mixed aquatic ecosystem. The dissipation, existence and stability of equilibria of the model are proved, and the ecological reproductive indexes for the extinction, survival and coexistence of autotrophs and mixotrophs are established. We also consider the influence of Holling type functional responses and abiotic factors on the coexistence and biomass of autotrophs and mixotrophs. It is shown that the intraguild predation structure is beneficial to phytoplankton biodiversity and provides an explanation for the phytoplankton paradox.

提出了一种具有种群内捕食结构的数学模型，用于描述混合良好的水生生态系统中自养生物和混合养生物之间的相互作用。证明了模型平衡的耗散性、存在性和稳定性，建立了自养和混合养生物灭绝、生存和共存的生态繁殖指标。我们还考虑了Holling型功能响应和非生物因子对自养和混合养生物共存和生物量的影响。研究表明，这种捕食结构有利于浮游植物的生物多样性，并为浮游植物悖论提供了解释。

引用次数: 1

The effect of spatial dynamics on the behaviour of an environmentally transmitted disease 空间动力学对环境传播疾病行为的影响

IF 2.8 4区数学 Q3 ECOLOGY

Journal of Biological Dynamics

Pub Date : 2022-04-11 DOI: 10.1080/17513758.2022.2061614

Ivy J Hindle, L. Forbes, S. Carver

Understanding the spread of pathogens through the environment is critical to a fuller comprehension of disease dynamics. However, many mathematical models of disease dynamics ignore spatial effects. We seek to expand knowledge around the interaction between the bare-nosed wombat (Vombatus ursinus) and sarcoptic mange (etiologic agent Sarcoptes scabiei), by extending an aspatial mathematical model to include spatial variation. S. scabiei was found to move through our modelled region as a spatio-temporal travelling wave, leaving behind pockets of localized host extinction, consistent with field observations. The speed of infection spread was also comparable with field research. Our model predicts that the inclusion of spatial dynamics leads to the survival and recovery of affected wombat populations when an aspatial model predicts extinction. Collectively, this research demonstrates how environmentally transmitted S. scabiei can result in travelling wave dynamics, and that inclusion of spatial variation reveals a more resilient host population than aspatial modelling approaches.

了解病原体在环境中的传播对于更全面地了解疾病动态至关重要。然而，许多疾病动力学的数学模型忽略了空间效应。我们试图通过扩展空间数学模型以包括空间变化来扩展关于裸鼻袋熊(Vombatus ursinus)和疥疮管理(病因Sarcoptes scabiei)之间相互作用的知识。发现疥螨以时空行波的形式在我们的模拟区域内移动，留下了局部宿主灭绝的小块，与实地观测结果一致。感染传播的速度也与实地研究相当。我们的模型预测，当空间模型预测灭绝时，空间动力学的包含导致受影响袋熊种群的生存和恢复。总的来说，这项研究证明了环境传播的疥螨如何导致行波动力学，并且包含空间变异揭示了比空间建模方法更具弹性的宿主种群。

引用次数: 2

Comparison of classical tumour growth models for patient derived and cell-line derived xenografts using the nonlinear mixed-effects framework 使用非线性混合效应框架比较患者来源和细胞系来源异种移植物的经典肿瘤生长模型

IF 2.8 4区数学 Q3 ECOLOGY

Journal of Biological Dynamics

Pub Date : 2022-04-11 DOI: 10.1080/17513758.2022.2061615

Dimitrios Voulgarelis, K. Bulusu, J. Yates

In this study we compare seven mathematical models of tumour growth using nonlinear mixed-effects which allows for a simultaneous fitting of multiple data and an estimation of both mean behaviour and variability. This is performed for two large datasets, a patient-derived xenograft (PDX) dataset consisting of 220 PDXs spanning six different tumour types and a cell-line derived xenograft (CDX) dataset consisting of 25 cell lines spanning eight tumour types. Comparison of the models is performed by means of visual predictive checks (VPCs) as well as the Akaike Information Criterion (AIC). Additionally, we fit the models to 500 bootstrap samples drawn from the datasets to expand the comparison of the models under dataset perturbations and understand the growth kinetics that are best fitted by each model. Through qualitative and quantitative metrics the best models are identified the effectiveness and practicality of simpler models is highlighted

在这项研究中，我们使用非线性混合效应比较了肿瘤生长的七个数学模型，该模型允许同时拟合多个数据并估计平均行为和变异性。这是针对两个大型数据集进行的，一个是由跨越六种不同肿瘤类型的220个PDX组成的患者来源的异种移植物（PDX）数据集，另一个是包括跨越八种肿瘤类型的25个细胞系的细胞系来源的异种移植（CDX）数据集中。通过视觉预测检查（VPCs）和Akaike信息标准（AIC）对模型进行比较。此外，我们将模型拟合到从数据集中提取的500个引导样本中，以扩展数据集扰动下模型的比较，并了解每个模型最适合的生长动力学。通过定性和定量指标，确定了最佳模型，强调了更简单模型的有效性和实用性

引用次数: 4

Impact of information and Lévy noise on stochastic COVID-19 epidemic model under real statistical data 真实统计数据下信息和lsamvy噪声对随机COVID-19流行模型的影响

IF 2.8 4区数学 Q3 ECOLOGY

Journal of Biological Dynamics

Pub Date : 2022-03-26 DOI: 10.1080/17513758.2022.2055172

Peijiang Liu, Lifang Huang, Anwarud Din, Xiangxiang Huang

In this paper, we consider the dynamical behaviour of a stochastic coronavirus (COVID-19) susceptible-infected-removed epidemic model with the inclusion of the influence of information intervention and Lévy noise. The existence and uniqueness of the model positive solution are proved. Then, we establish a stochastic threshold as a sufficient condition for the extinction and persistence in mean of the disease. Based on the available COVID-19 data, the parameters of the model were estimated and we fit the model with real statistics. Finally, numerical simulations are presented to support our theoretical results.

本文考虑了包含信息干预和lsamvy噪声影响的随机冠状病毒(COVID-19)易感-感染-去除流行病模型的动力学行为。证明了模型正解的存在唯一性。然后，我们建立了一个随机阈值作为疾病灭绝和持续的充分条件。基于现有的COVID-19数据，对模型的参数进行估计，并用实际统计量对模型进行拟合。最后，给出了数值模拟来支持理论结果。

引用次数: 0

Persistence and extinction of a modified Leslie–Gower Holling-type II two-predator one-prey model with Lévy jumps 具有lsamvy跳跃的改进的Leslie-Gower holling型II双捕食者单猎物模型的持续和灭绝

IF 2.8 4区数学 Q3 ECOLOGY

Journal of Biological Dynamics

Pub Date : 2022-03-14 DOI: 10.1080/17513758.2022.2050313

Yongxin Gao, Fan Yang

This paper is concerned with a modified Leslie–Gower and Holling-type II two-predator one-prey model with Lévy jumps. First, we use an Ornstein–Uhlenbeck process to describe the environmental stochasticity and prove that there is a unique positive solution to the system. Moreover, sufficient conditions for persistence in the mean and extinction of each species are established. Finally, we give some numerical simulations to support the main results.

本文研究了一类具有lsamvy跳跃的改进的Leslie-Gower和holling - II型双捕食者单猎物模型。首先，我们利用Ornstein-Uhlenbeck过程来描述系统的环境随机性，并证明了系统存在唯一正解。此外，还建立了每一物种平均存续和灭绝的充分条件。最后，给出了一些数值模拟来支持主要结果。

引用次数: 2

SARS-CoV-2 and self-medication in Cameroon: a mathematical model. 喀麦隆的SARS-CoV-2和自我用药:一个数学模型。

IF 2.8 4区数学 Q3 ECOLOGY

Journal of Biological Dynamics

Pub Date : 2021-12-01 DOI: 10.1080/17513758.2021.1883130

Jude D Kong, Rinel F Tchuendom, Samuel A Adeleye, Jummy F David, Fikreab Solomon Admasu, Emmanuel A Bakare, Nourridine Siewe

Self-medication is an important initial response to illness in Africa. This mode of medication is often done with the help of African traditional medicines. Because of the misconception that African traditional medicines can cure/prevent all diseases, some Africans may opt for COVID-19 prevention and management by self-medicating. Thus to efficiently predict the dynamics of COVID-19 in Africa, the role of the self-medicated population needs to be taken into account. In this paper, we formulate and analyse a mathematical model for the dynamics of COVID-19 in Cameroon. The model is represented by a system of compartmental age-structured ODEs that takes into account the self-medicated population and subdivides the human population into two age classes relative to their current immune system strength. We use our model to propose policy measures that could be implemented in the course of an epidemic in order to better handle cases of self-medication.

在非洲，自我药疗是对疾病的重要初步反应。这种治疗方式通常是在非洲传统药物的帮助下完成的。由于误解非洲传统药物可以治愈/预防所有疾病，一些非洲人可能会选择通过自我治疗来预防和管理COVID-19。因此，为了有效预测2019冠状病毒病在非洲的动态，需要考虑自我用药人群的作用。在本文中，我们制定并分析了喀麦隆COVID-19动态的数学模型。该模型由间隔年龄结构的ode系统表示，该系统考虑了自我用药人群，并将人群细分为相对于其当前免疫系统强度的两个年龄段。我们利用我们的模型提出在疫情期间可以实施的政策措施，以便更好地处理自我药疗的情况。

引用次数: 9

Threshold dynamics of a HCV model with virus to cell transmission in both liver with CTL immune response and the extrahepatic tissue. 具有CTL免疫应答的肝脏和肝外组织中病毒向细胞传播的HCV模型的阈值动力学

IF 2.8 4区数学 Q3 ECOLOGY

Journal of Biological Dynamics

Pub Date : 2021-12-01 DOI: 10.1080/17513758.2020.1859632

Xinli Hu, Jianquan Li, Xiaomei Feng

In this paper, a deterministic model characterizing the within-host infection of Hepatitis C virus (HCV) in intrahepatic and extrahepatic tissues is presented. In addition, the model also includes the effect of the cytotoxic T lymphocyte (CTL) immunity described by a linear activation rate by infected cells. Firstly, the non-negativity and boundedness of solutions of the model are established. Secondly, the basic reproduction number $R_{01}$ and immune reproduction number $R_{02}$ are calculated, respectively. Three equilibria, namely, infection-free, CTL immune response-free and infected equilibrium with CTL immune response are discussed in terms of these two thresholds. Thirdly, the stability of these three equilibria is investigated theoretically as well as numerically. The results show that when $R_{01} < 1$ , the virus will be cleared out eventually and the CTL immune response will also disappear; when $R_{02} < 1 < R_{01}$ , the virus persists within the host, but the CTL immune response disappears eventually; when $R_{02} > 1$ , both of the virus and the CTL immune response persist within the host. Finally, a brief discussion will be given.

本文提出了一种表征丙型肝炎病毒(HCV)在肝内和肝外组织中宿主内感染的确定性模型。此外，该模型还包括受感染细胞线性激活率描述的细胞毒性T淋巴细胞(CTL)免疫的影响。首先，建立了模型解的非负性和有界性。其次，分别计算基本繁殖数R01和免疫繁殖数R02。根据这两个阈值讨论了无感染平衡、无CTL免疫反应平衡和有CTL免疫反应的感染平衡。第三，对这三种平衡的稳定性进行了理论和数值研究。结果表明，当R011发生时，病毒最终被清除，CTL免疫应答也随之消失;当R021R01时，病毒在宿主体内持续存在，但CTL免疫应答最终消失;当R02>1时，病毒和CTL免疫反应都在宿主体内持续存在。最后，将作一个简短的讨论。

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引用次数: 6

Global stability of a delayed and diffusive virus model with nonlinear infection function. 一类具有非线性感染函数的延迟扩散病毒模型的全局稳定性。

IF 2.8 4区数学 Q3 ECOLOGY

Journal of Biological Dynamics

Pub Date : 2021-12-01 DOI: 10.1080/17513758.2021.1922770

Yan Geng, Jinhu Xu

This paper studies a delayed viral infection model with diffusion and a general incidence rate. A discrete-time model was derived by applying nonstandard finite difference scheme. The positivity and boundedness of solutions are presented. We established the global stability of equilibria in terms of $R_{0}$ by applying Lyapunov method. The results showed that if $R_{0}$ is less than 1, then the infection-free equilibrium $E_{0}$ is globally asymptotically stable. If $R_{0}$ is greater than 1, then the infection equilibrium $E_{*}$ is globally asymptotically stable. Numerical experiments are carried out to illustrate the theoretical results.

本文研究了具有扩散和一般发病率的延迟病毒感染模型。采用非标准有限差分格式建立了离散时间模型。给出了解的正性和有界性。利用Lyapunov方法建立了R0下均衡的全局稳定性。结果表明，当R0小于1时，无感染平衡点E0是全局渐近稳定的。若R0大于1，则感染平衡点E *是全局渐近稳定的。数值实验对理论结果进行了验证。

引用次数: 1

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