3,007,458 results
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Journal Article
Complex spatio-temporal features in meg data
Magnetoencephalography (MEG) brain signals are studied usinga method for characterizing complex nonlinear dynamics. This approach usesthe value of $d_\infty$ (d-infinite) to characterize the system’s asymptotic chaoticbehavior. A novel procedure has been developed to extract this parameterfrom time…
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Sensitivity and uncertainty analyses for a SARS model with time-varying inputs and outputs
This paper presents a statistical study of a deterministic model for the transmissiondynamics and control of severe acute respiratory syndrome (SARS). The effect of themodel parameters on the dynamics of the disease is analyzed using sensitivity anduncertainty analyses. The response (or output) of…
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Journal Article
The influence of infectious diseases on population genetics
Malaria is the vector-transmitted disease that causes the highestmorbidity and mortality in humans. Motivated by the known influenceof sickle-cell anemia on the morbidity and mortality ofmalaria-infected humans, we study the effect of malaria on the genetic composition of a host (human) population…
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Response of equilibrium states to spatial environmental heterogeneity in advective systems
Much ecological research involves identifying connections between abiotic forcing and population densities or distributions. We present theory that describes this relationship for populations in media with strong unidirectional flow (e.g., aquatic organisms in streams and rivers). Typically…
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Journal Article
From the guest editors
In September of 2003, on the tail of the outbreak of Severe AcuteRespiratory Syndrome (SARS) in the Greater Toronto Area, MITACS(www.mitacs.ca), one of Canada's Networks of Centres ofExcellence, teamed up with Health Canada in funding a workshopentitled the MITACS-PIMS-Health Canada meeting on SARS…
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Journal Article
Competition and Dispersal Delays in Patchy Environments
Dispersal delays are introduced into a competition model for two species that disperse among $n$ identical patches. The model is formulated as a system of integro-differential equations with an arbitrary distribution of dispersal times between patches. By identifying steady states and analyzing…
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Journal Article
Lyapunov functions for tuberculosis models with fast and slow progression
The spread of tuberculosis is studied through two models whichinclude fast and slow progression to the infected class. For each model, Lyapunovfunctions are used to show that when the basic reproduction numberis less than or equal to one, the disease-free equilibrium is globally…
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Journal Article
The stability of stationary fronts for a discrete nerve axon model
We consider the stability of single-front stationary solutions to a spatially discrete reaction-diffusion equation which models front propagation in a nerve axon. The solution's stability depends on the coupling parameter, changing from stable to unstable and from unstable to stable at a countably…
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Journal Article
Insect development under predation risk, variable temperature, and variable food quality
We model the development of an individual insect, a grasshopper, through its nymphal period as a function of a trade-off between prey vigilance and nutrient intake in a changing environment. Both temperature and food quality may be variable. We scale up to the population level using natural…
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Journal Article
Modelling the human immune response mechanisms to mycobacterium tuberculosis infection in the lungs
This work elaborates on the effects of cytotoxic lymphocytes (CTLs)and other immune mechanisms in determining whether a TB-infected individualwill develop active or latent TB. It answers one intriguing question: whydo individuals infected with Mycobacterium tuberculosis (Mtb) experience…
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Journal Article
Alternative models for cyclic lemming dynamics
Many natural population growths and interactions are affected byseasonal changes, suggesting that these natural population dynamicsshould be modeled by nonautonomous differential equations instead ofautonomous differential equations. Through a series of carefullyderived models of the well…
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Journal Article
On the stabilizing effect of cannibalism in stage-structured population models
In this paper we give a contribution to the systematic investigation of cannibalism in predator-prey models commenced since the publication of the paper by Kohlmeier and Ebenhöh in 1995. We present a stage-structured predator-prey model and study its dynamics. We use a Hopf bifurcation analysis to…
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Journal Article
Remark on the Paper by Rao And Kakehashi (2005)
The paper by Rao and Kakehashi [1]uses the Weibull distribution (given by equation (3) in the paper)and a truncated version of it (given by equations (4) and (5))to model HIV/AIDS data in India.After a careful reading, I have found that all of the results presentedin the appendix are incorrect…
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From the Guest Editor
This Special Issue of Mathematical Biosciences and Engineering (MBE)contains a few of the papers presented at a special session in Mathematical Biologyat the Regional Meeting of the American Mathematical Society, held in Lincoln, Nebraska,on October 21-23, 2005. The AMS meeting was preceded by a…
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Journal Article
Simulation of Pulsatile Flow of Blood in Stenosed Coronary Artery Bypass with Graft
In this paper, we investigate the behavior of the pulsatile bloodflow in a stenosed right coronary artery with a bypass graft. Thehuman blood is assumed to be a non-Newtonian fluid and its viscousbehavior is described by the Carreau model. The transientphenomena of blood flow though the stenosed…
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Mathematical epidemiology of HIV/AIDS in cuba during the period 1986-2000
The dynamics of HIV/AIDS epidemics in a specific region is de-termined not only by virology and virus transmission mechanisms, but also byregion's socioeconomic aspects. In this paper we study the HIV transmissiondynamics for Cuba. We modify the model of de Arazoza and Lounes [1] accord-ing to the…
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Journal Article
Multiscale Image Registration
A multiscale image registration technique is presented for the registration of medical images that contain significant levels of noise. An overview of the medical image registration problem is presented, and various registration techniques are discussed. Experiments using mean squares, normalized…
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Journal Article
Optimal control for management of an invasive plant species
Invasive plant populations typically consist of a large (main) focus and several smaller outlier populations. Management of the spread of invasives requires repeated control measures, constrained by limited funding and effort. Posing this as a control problem, we investigate whether it is best to…
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Journal Article
Analysis of Blood Flow Velocity and Pressure Signals using the Multipulse Method
This paper shows how the multipulse methodfrom digital signal processing can be used to accurately synthesizesignals obtained from blood pressure and blood flow velocity sensors duringposture change from sitting to standing. Themultipulse method can be used to analyze signals that are composed…
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Journal Article
An individual, stochastic model of growth incorporating state-dependent risk and random foraging and climate
We model the effects of both stochastic and deterministic temperature variations on arthropod predator-prey systems. Specifically, we study the stochastic dynamics of arthropod predator-prey interactions under a varying temperature regime, and we develop an individual model of a prey under pressure…
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