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2002-01-01

Lewis, Mark A., Bingtuan Li, Hans F. Weinberger

 One crucial measure of a species' invasiveness is the rate at which it spreads into a competitor's environment. A heuristic spread rate formula for a spatially explicit, two-species competition model relies on `linear determinacy' which equates spread rate in the full nonlinear model with spread...

1992

Kouritzin, Michael, Heunis, A.J.

Let μ be a positive finite Borel measure on the real line R. For t ≥ 0 let et · E1 and E2 denote, respectively, the linear spans in L2(R, μ) of {eisx, s > t} and {eisx, s < 0}. Let θ: R → C such that ∥θ∥ = 1, denote by αt(θ, μ) the angle between θ · et · E1 and E2. The problems considered here...

2011

Newton, Fraser, Kouritzin, Michael

A CAPTCHA is an automatically generated test designed to distinguish between humans and computer programs; specifically, they are designed to be easy for humans but difficult for computer programs to pass in order to prevent the abuse of resources by automated bots. They are commonly seen...

2019-01-01

Mariana B. Nagy-Reis, Mark A. Lewis, William F. Jensen, Mark S. Boyce

Understanding the underlying mechanisms driving population demographics such as species-habitat relationships and the spatial scale in which these relationships occur is essential for developing optimal management strategies. Here we evaluated how landscape characteristics and winter severity...

2023-09-27

Brush, Micah, Lewis, Mark A.

Mountain pine beetle (MPB) in Canada have spread well beyond their historical range. Accurate modelling of the long-term dynamics of MPB is critical for assessing the risk of further expansion and informing management strategies, particularly in the context of climate change and variable forest...

1995-01-01

Sherratt, J. A., Lewis, Mark A., Fowler, A. C.

Irregularities in observed population densities have traditionally been attributed to discretization of the underlying dynamics. We propose an alternative explanation by demonstrating the evolution of spatiotemporal chaos in reaction-diffusion models for predator-prey interactions. The chaos is...

2017-04-01

Guillaume Bastille-Rousseau, Dennis L. Murray, James A. Schaefer, Mark A. Lewis, Shane P. Mahoney, Jonathan R. Potts

Movement influences a myriad of ecological processes operating at multiple spatial and temporal scales. Yet our understanding of animal movement is limited by the resolution of data that can be obtained from individuals. Traditional approaches implicitly assume that movement decisions are made at...

2019-05-04

Thomas Hillen

We identify seven-tone (heptatonic) scales as a sequence of minor and major thirds, where we use a zero to indicate a minor third and a one for a major third. Each proper seven-tone scale is then represented by a {0,1}-sequence of length seven. On these {0,1}-sequences we define group operations...

2016-03-14

Frédéric M. Hamelin, François Castella, Valentin Doli, Benoît Marçais, Virginie Ravigné, Mark A. Lewis

Sexual reproduction and dispersal are often coupled in organisms mixing sexual and asexual reproduction, such as fungi. The aim of this study is to evaluate the impact of mate limitation on the spreading speed of fungal plant parasites. Starting from a simple model with two coupled partial...

2014-01-01

Potts, Jonathan R., Lewis, Mark A.

Territory formation is ubiquitous throughout the animal kingdom. At the individual level, various behaviours attempt to exclude conspecifics from regions of space. At the population level, animals often segregate into distinct territorial areas. Consequently, it should be possible to derive...