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The interplay between fishery yield and top predator culling in a multispecies fishery context. 多物种渔业环境下渔业产量与顶级捕食者淘汰之间的相互作用。
IF 1.1 4区 数学
Mathematical Medicine and Biology-A Journal of the Ima Pub Date : 2020-09-15 DOI: 10.1093/imammb/dqz017
Michel Iskin da S Costa, Lucas Dos Anjos
{"title":"The interplay between fishery yield and top predator culling in a multispecies fishery context.","authors":"Michel Iskin da S Costa,&nbsp;Lucas Dos Anjos","doi":"10.1093/imammb/dqz017","DOIUrl":"https://doi.org/10.1093/imammb/dqz017","url":null,"abstract":"<p><p>In food webs, fishery can play the role of top predator, competing thus with other top predators for valuable food resources. In this view, it has been claimed in fisheries management that culling of top predators can be a means to improve fishery yield. To investigate this hypothesis, we use theoretical population models to assess in a multispecies context how fishery yield from target species harvest responds to top predator cull. Defying crisp summary, the four analysed food web models show that this response may be either positive or negative or both, indicating that in terms of multispecies fishery management the harvest yield may not accrue as a consequence of predator removal. In addition, this multitude of behaviours points also to the fact that the response of fishery yield to top predator cull may be difficult to assess.</p>","PeriodicalId":49863,"journal":{"name":"Mathematical Medicine and Biology-A Journal of the Ima","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2020-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/imammb/dqz017","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37536642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
The influence of a lipid reservoir on the tear film formation. 脂质储层对泪膜形成的影响。
IF 1.1 4区 数学
Mathematical Medicine and Biology-A Journal of the Ima Pub Date : 2020-09-10 DOI: 10.1093/imammb/dqz018
Kara L Maki, Richard J Braun, Gregory A Barron
{"title":"The influence of a lipid reservoir on the tear film formation.","authors":"Kara L Maki,&nbsp;Richard J Braun,&nbsp;Gregory A Barron","doi":"10.1093/imammb/dqz018","DOIUrl":"https://doi.org/10.1093/imammb/dqz018","url":null,"abstract":"<p><p>We present a mathematical model to study the influence of a lipid reservoir, seen experimentally, at the lid margin on the formation and relaxation of the tear film during a partial blink. Applying the lubrication limit, we derive two coupled non-linear partial differential equations characterizing the evolution of the aqueous tear fluid and the covering insoluble lipid concentration. Departing from prior works, we explore a new set of boundary conditions (BCs) enforcing hypothesized lipid concentration dynamics at the lid margins. Using both numerical and analytical approaches, we find that the lipid-focused BCs strongly impact tear film formation and thinning rates. Specifically, during the upstroke of the eyelid, we find specifying the lipid concentration at the lid margin accelerates thinning. Parameter regimes that cause tear film formation success or failure are identified. More importantly, this work expands our understanding of the consequences of lipid dynamics near the lid margins for tear film formation.</p>","PeriodicalId":49863,"journal":{"name":"Mathematical Medicine and Biology-A Journal of the Ima","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2020-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/imammb/dqz018","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37584469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Informed and uninformed empirical therapy policies. 知情和不知情的经验治疗政策。
IF 1.1 4区 数学
Mathematical Medicine and Biology-A Journal of the Ima Pub Date : 2020-09-10 DOI: 10.1093/imammb/dqz015
Nicolas Houy, Julien Flaig
{"title":"Informed and uninformed empirical therapy policies.","authors":"Nicolas Houy,&nbsp;Julien Flaig","doi":"10.1093/imammb/dqz015","DOIUrl":"https://doi.org/10.1093/imammb/dqz015","url":null,"abstract":"<p><p>We argue that a proper distinction must be made between informed and uninformed decision making when setting empirical therapy policies, as this allows one to estimate the value of gathering more information about the pathogens and their transmission and thus to set research priorities. We rely on the stochastic version of a compartmental model to describe the spread of an infecting organism in a health care facility and the emergence and spread of resistance to two drugs. We focus on information and uncertainty regarding the parameters of this model. We consider a family of adaptive empirical therapy policies. In the uninformed setting, the best adaptive policy allowsone to reduce the average cumulative infected patient days over 2 years by 39.3% (95% confidence interval (CI), 30.3-48.1%) compared to the combination therapy. Choosing empirical therapy policies while knowing the exact parameter values allows one to further decrease the cumulative infected patient days by 3.9% (95% CI, 2.1-5.8%) on average. In our setting, the benefit of perfect information might be offset by increased drug consumption.</p>","PeriodicalId":49863,"journal":{"name":"Mathematical Medicine and Biology-A Journal of the Ima","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2020-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/imammb/dqz015","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37491037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Allostery in oligomeric receptor models. 低聚受体模型的变构。
IF 1.1 4区 数学
Mathematical Medicine and Biology-A Journal of the Ima Pub Date : 2020-09-10 DOI: 10.1093/imammb/dqz016
Gregory Douglas Conradi Smith
{"title":"Allostery in oligomeric receptor models.","authors":"Gregory Douglas Conradi Smith","doi":"10.1093/imammb/dqz016","DOIUrl":"https://doi.org/10.1093/imammb/dqz016","url":null,"abstract":"<p><p>We show how equilibrium binding curves of receptor homodimers can be expressed as rational polynomial functions of the equilibrium binding curves of the constituent monomers, without approximation and without assuming independence of receptor monomers. Using a distinguished spanning tree construction for reduced graph powers, the method properly accounts for thermodynamic constraints and allosteric interactions between receptor monomers (i.e. conformational coupling). The method is completely general; it begins with an arbitrary undirected graph representing the topology of a monomer state-transition diagram and ends with an algebraic expression for the equilibrium binding curve of a receptor oligomer composed of two or more identical and indistinguishable monomers. Several specific examples are analysed, including guanine nucleotide-binding protein-coupled receptor dimers and tetramers composed of multiple 'ternary complex' monomers.</p>","PeriodicalId":49863,"journal":{"name":"Mathematical Medicine and Biology-A Journal of the Ima","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2020-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/imammb/dqz016","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37445180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Optimal vaccine allocation during the mumps outbreak in two SIR centres. 两个SIR中心流行性腮腺炎暴发期间疫苗的最佳分配。
IF 1.1 4区 数学
Mathematical Medicine and Biology-A Journal of the Ima Pub Date : 2020-09-10 DOI: 10.1093/imammb/dqz012
Alexey A Chernov, Mark Y Kelbert, Aleksandr A Shemendyuk
{"title":"Optimal vaccine allocation during the mumps outbreak in two SIR centres.","authors":"Alexey A Chernov,&nbsp;Mark Y Kelbert,&nbsp;Aleksandr A Shemendyuk","doi":"10.1093/imammb/dqz012","DOIUrl":"https://doi.org/10.1093/imammb/dqz012","url":null,"abstract":"<p><p>The aim of this work is to investigate the optimal vaccine sharing between two susceptible, infected, removed (SIR) centres in the presence of migration fluxes of susceptibles and infected individuals during the mumps outbreak. Optimality of the vaccine allocation means the minimization of the total number of lost working days during the whole period of epidemic outbreak $[0,t_f]$, which can be described by the functional $Q=int _0^{t_f}I(t),{textrm{d}}t$, where $I(t)$ stands for the number of infectives at time $t$. We explain the behaviour of the optimal allocation, which depends on the model parameters and the amount of vaccine available $V$.</p>","PeriodicalId":49863,"journal":{"name":"Mathematical Medicine and Biology-A Journal of the Ima","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2020-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/imammb/dqz012","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37388028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 7
Analytic solutions for calcium ion fertilisation waves on the surface of eggs - erratum. 卵表面钙离子受精波的解析解-勘误。
IF 1.1 4区 数学
Mathematical Medicine and Biology-A Journal of the Ima Pub Date : 2020-09-10 DOI: 10.1093/imammb/dqaa002
Bronwyn H Bradshaw-Hajek, Philip Broadbridge
{"title":"Analytic solutions for calcium ion fertilisation waves on the surface of eggs - erratum.","authors":"Bronwyn H Bradshaw-Hajek,&nbsp;Philip Broadbridge","doi":"10.1093/imammb/dqaa002","DOIUrl":"https://doi.org/10.1093/imammb/dqaa002","url":null,"abstract":"<p><p>The paper, \"Analytic solutions for calcium ion fertilisation waves on the surface of eggs\" by the current authors (this journal 2019), adopted an incorrect solution to Legendre's equation that had been tabulated in a well known compendium of solutions of differential equations. The solution to the linear equation and the consequent solution of the considered nonlinear problem, are corrected here. The solution maintains the same character and the conclusions are the same. Numerical evaluations and graphic outputs have been modified.</p>","PeriodicalId":49863,"journal":{"name":"Mathematical Medicine and Biology-A Journal of the Ima","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2020-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/imammb/dqaa002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37749033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Modelling the inclusion of swelling pressure in a tissue level poroviscoelastic model of cartilage deformation. 软骨变形的组织水平孔粘弹性模型中溶胀压力的模拟。
IF 1.1 4区 数学
Mathematical Medicine and Biology-A Journal of the Ima Pub Date : 2020-09-10 DOI: 10.1093/imammb/dqaa001
Jonathan P Whiteley, Eamonn A Gaffney
{"title":"Modelling the inclusion of swelling pressure in a tissue level poroviscoelastic model of cartilage deformation.","authors":"Jonathan P Whiteley,&nbsp;Eamonn A Gaffney","doi":"10.1093/imammb/dqaa001","DOIUrl":"https://doi.org/10.1093/imammb/dqaa001","url":null,"abstract":"<p><p>Swelling pressure in the interstitial fluid within the pores of cartilage tissue is known to have a significant effect on the rheology of cartilage tissue. The swelling pressure varies rapidly within thin regions inside pores known as Debye layers, caused by the presence of fixed charge, as observed in cartilage. Tissue level calculation of cartilage deformation therefore requires resolution of three distinct spatial scales: the Debye lengthscale within individual pores; the lengthscale of an individual pore; and the tissue lengthscale. We use asymptotics to construct a leading order approximation to the swelling pressure within pores, allowing the swelling pressure to be systematically included within a fluid-solid interaction model at the level of pores in cartilage. We then use homogenization to derive tissue level equations for cartilage deformation that are very similar to those governing the finite deformation of a poroviscoelastic body. The equations derived permit the spatial variations in porosity and electric charge that occur in cartilage tissue. Example solutions are then used to confirm the plausibility of the model derived and to consider the impact of fixed charge heterogeneity, illustrating that local fixed charge loss is predicted to increase deformation gradients under confined compression away from, rather than at, the site of loss.</p>","PeriodicalId":49863,"journal":{"name":"Mathematical Medicine and Biology-A Journal of the Ima","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2020-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/imammb/dqaa001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37656318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Stochastic optimal control of pre-exposure prophylaxis for HIV infection. HIV感染暴露前预防的随机最优控制。
IF 1.1 4区 数学
Mathematical Medicine and Biology-A Journal of the Ima Pub Date : 2020-09-08 DOI: 10.1093/imammb/dqac003
Jasmina Ðorđević, Kristina Rognlien Dahl
{"title":"Stochastic optimal control of pre-exposure prophylaxis for HIV infection.","authors":"Jasmina Ðorđević, Kristina Rognlien Dahl","doi":"10.1093/imammb/dqac003","DOIUrl":"https://doi.org/10.1093/imammb/dqac003","url":null,"abstract":"The aim of the paper is to apply the stochastic optimal control problem in order to optimize the number of individual which will have the pre-exposure prophylaxis (PReP) treatment in the stochastic model for HIV/AIDS with PReP. By using the stochastic maximum principle, we derive the stochastic optimal control of PReP for the unconstrained control problem. Furthermore, by combining the stochastic maximum principle with a version of the Lagrange multiplier method, we solve the PReP problem for two different types of budget constrains with a given constrain for the costs (possible of different kind, transportation, price of the treatment, etc.). Obtained results for the different percentage of the individuals who got the vaccine, as well as results for unconstrained and constrained problems, are illustrated by a numerical example.","PeriodicalId":49863,"journal":{"name":"Mathematical Medicine and Biology-A Journal of the Ima","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2020-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75075069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Potential reduction in transmission of COVID-19 by digital contact tracing systems 通过数字接触者追踪系统可能减少COVID-19的传播
IF 1.1 4区 数学
Mathematical Medicine and Biology-A Journal of the Ima Pub Date : 2020-09-01 DOI: 10.1101/2020.08.27.20068346
M. Plank, A. James, Audrey Lustig, N. Steyn, Rachelle N. Binny, S. Hendy
{"title":"Potential reduction in transmission of COVID-19 by digital contact tracing systems","authors":"M. Plank, A. James, Audrey Lustig, N. Steyn, Rachelle N. Binny, S. Hendy","doi":"10.1101/2020.08.27.20068346","DOIUrl":"https://doi.org/10.1101/2020.08.27.20068346","url":null,"abstract":"Digital tools are being developed to support contact tracing as part of the global effort to control the spread of COVID-19. These include smartphone apps, Bluetooth-based proximity detection, location tracking, and automatic exposure notification features. Evidence on the effectiveness of alternative approaches to digital contact tracing is so far limited. We use an age-structured branching process model of the transmission of COVID-19 in different settings to estimate the potential of manual contact tracing and digital tracing systems to help control the epidemic. We investigate the effect of the uptake rate and proportion of contacts recorded by the digital system on key model outputs: the effective reproduction number, the mean outbreak size after 30 days, and the probability of elimination. We show that effective manual contact tracing can reduce the effective reproduction number from 2.4 to around 1.5. The addition of a digital tracing system with a high uptake rate over 75% could further reduce the effective reproduction number to around 1.1. Fully automated digital tracing without manual contact tracing is predicted to be much less effective. We conclude that, for digital tracing systems to make a significant contribution to the control of COVID-19, they need be designed in close conjunction with public health agencies to support and complement manual contact tracing by trained professionals.","PeriodicalId":49863,"journal":{"name":"Mathematical Medicine and Biology-A Journal of the Ima","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89676434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 9
A stochastic model for cancer metastasis: branching stochastic process with settlement. 肿瘤转移的随机模型:带有沉降的分支随机过程。
IF 1.1 4区 数学
Mathematical Medicine and Biology-A Journal of the Ima Pub Date : 2020-05-29 DOI: 10.1093/imammb/dqz009
Christoph Frei, Thomas Hillen, Adam Rhodes
{"title":"A stochastic model for cancer metastasis: branching stochastic process with settlement.","authors":"Christoph Frei,&nbsp;Thomas Hillen,&nbsp;Adam Rhodes","doi":"10.1093/imammb/dqz009","DOIUrl":"https://doi.org/10.1093/imammb/dqz009","url":null,"abstract":"<p><p>We introduce a new stochastic model for metastatic growth, which takes the form of a branching stochastic process with settlement. The moving particles are interpreted as clusters of cancer cells, while stationary particles correspond to micro-tumours and metastases. The analysis of expected particle location, their locational variance, the furthest particle distribution and the extinction probability leads to a common type of differential equation, namely, a non-local integro-differential equation with distributed delay. We prove global existence and uniqueness results for this type of equation. The solutions' asymptotic behaviour for long time is characterized by an explicit index, a metastatic reproduction number $R_0$: metastases spread for $R_{0}>1$ and become extinct for $R_{0}<1$. Using metastatic data from mouse experiments, we show the suitability of our framework to model metastatic cancer.</p>","PeriodicalId":49863,"journal":{"name":"Mathematical Medicine and Biology-A Journal of the Ima","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2020-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/imammb/dqz009","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37303376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 5
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