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2009-01-01

Derocher, Andrew E., Klanjscek, Tin, Molnár, Péter K., Lewis, Mark A., Obbard, Martyn E.

Many species experience large fluctuations in food availability and depend on energy from fat and protein stores for survival, reproduction and growth. Body condition and, more specifically, energy stores thus constitute key variables in the life history of many species. Several indices exist to...

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...

2009-12-22

Frédéric M. Hamelin, Mark A. Lewis

In this paper, elements of differential game theory are used to analyze a spatially explicit home range model for interactingwolf packs when movement behavior is uncertain. The model consists of a system of partial differential equations whose parameters reflect the movement behavior of...

2016-06-13

Vlastimil Kˇrivan, Mark Lewis, Barbara J. Bentz, Sharon Bewick, Suzanne M. Lenhart, Andrew Liebhold

Tree-killing bark beetles are major disturbance agents affecting coniferous forest ecosystems. The role of environmental conditions on driving beetle outbreaks is becoming increasingly important as global climatic change alters environmental factors, such as drought stress, that, in turn, govern...

2016-01-01

Schlägel, Ulrike E, Lewis, Mark A.

When sampling animal movement paths, the frequency at which location measurements are attempted is a critical feature for data analysis. Important quantities derived from raw data, e.g. travel distance or sinuosity, can differ largely based on the temporal resolution of the data. Likewise, when...

2019-01-01

Mark A. Lewis, Zhisheng Shuai, P. van den Driessche

A general framework for threshold parameters in population dynamics is developed using the concept of target reproduction numbers. This framework identies reproduction numbers and other threshold parameters in the literature in terms of their roles in population control. The framework is applied...

2014-10-01

Potts, Jonathan R, Marie Auger-M´eth´e, Karl Mokross, Mark A. Lewis

Complex systems of moving and interacting objects are ubiquitous in the natural and social sciences. Predicting their behaviour often requires models that mimic these systems with sufficient accuracy, while accounting for their inherent stochasticity. Although tools exist to determine which of a...

2014

Wu, B., Newton, F., Kouritzin, Michael A.

A new class of discrete random fields designed for quick simulation and covariance inference under inhomogenous conditions is introduced and studied. Simulation of these correlated fields can be done in a single pass instead of relying on multi-pass convergent methods like the Gibbs Sampler or...

2017-01-01

QIHUA HUANG, HAO WANG, MARK A. LEWIS

While some species spread upstream in river environments, not all invasive species are successful in spreading upriver. Here the dynamics of unidirectional water flow found in rivers can play a role in determining invasion success. We develop a continuous-discrete hybrid benthic-drift population...

2020-01-01

S. M. Fischer, M. Beck, L.-M. Herborg, M. A. Lewis

Human traffic along roads can be a major vector for infectious diseases and invasive species. Though most road traffic is local, a small number of long-distance trips can suffice to move an invasion or disease front forward. Therefore, understanding how many agents travel over long distances and...