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Dr. Murray Alexander

Physics


Murray Alexander Title: Adjunct Professor of Physics
Office: 2L22
Building: Centennial Hall
Phone: 204.786.9020
Email: mu.alexander@uwinnipeg.ca

Degrees:
Ph.D. (Manchester, 1973)

Courses:
(2021-2022)

Research Interests:

Astrophysics of Binary Star Systems

There are two projects.

  1. Explore mathematically the dynamical behaviour of an exoplanet orbiting a host star, taking into account observed precessional motion of both the star and the orbit, and resonances between the star’s oscillations and the orbital motion. Transitions into and out of resonance are being investigated to explain the period and primary eclipse anomalies in the observed data of several exoplanet systems in the Kepler and TESS surveys.
  2. Build a model of stellar winds arising from the late-type secondary in subdwarf OB binary systems caused by irradiation of the cool secondary star by the hot primary component. The interaction of the wind with the magnetic field of the secondary indirectly induces changes to the orbit which cause observable period changes in these systems, which remain unexplained.

Mathematical Modeling of Cell Function and Infectious Diseases

An effective approach to studying an infectious disease process is through mathematical and computational models - either at the population-level (epidemiology) or cellular-level (immunology). This offers a complement to experimental or clinical approaches, and can predict rich and sometimes unforeseen dynamical behavior. A recent example this approach has been to define the onset of severe forms of influenza as a ‘phase transition’ in the spread of viral infection in the epithelial layer of the lung.

Models of chemotaxis and competitive chemotactic processes are being investigated, incorporating simplified models of individual cells, and transport processes inside cells, to explain their motility and shape.

 

Publications:

  • M.E. Alexander, R. Kobes. Effects of vaccination and population structure on influenza epidemic spread in the presence of two circulating strains. BMC Public Health, 11(Suppl 1):S8, 2011.
  • M.E. Alexander, R. Kobes. Generating and solving the mean-field and pair-approximation equations in epidemiological models. arXiv: 1007.2883v1 [physics.soc-ph] (2010).
  • M.E. Alexander, R. Kobes. Expansion of the conditional probability function in a network with nearest-neighbour degree correlations. arXiv: 1007.0717 [phys-soc-ph] (2010).
  • M.E. Alexander, S.M. Dietrich, Y. Hua, and S.M. Moghadas. A comparative evaluation of modelling strategies for the effect of treatment and host interactions on the spread of drug resistance. J. Theor. Biol., 259: 253-263, 2009.
  • TJ Vincent, JD. Thiessen, LM Kurjewicz, SL Germscheid, AJ. Turner, P Zhilkin, ME Alexander, M Martin. Longitudinal Brain Size Measurements in APP/PS1 Transgenic Mice. Magnetic Resonance Insights 4: 1–8, 2010.
  • P. Zhilkin, M.E. Alexander, J. Sun. Nonlinear registration using variational principle for mutual information. Pattern Recognition, 2008, 41(8), p. 2493-2502.
  • Moghadas, S.M., M.E. Alexander & B.M. Sahai. Waning herd immunity: a challenge for eradication of measles. Rocky Mountain J. Math., 38(5):1587-1607, 2008.
  • M.E. Alexander, Moghadas S.M., Röst G., Wu J.-H. A delay differential model for pandemic influenza with antiviral treatment. Bull. Math. Biol., 70:382-397, 2008.
  • M.E. Alexander, C.S. Bowman, Z. Feng, M. Gardham, S.M. Moghadas, G. Röst, J. Wu, P. Yan. Emergence of drug-resistance: implications for antiviral control of pandemic Influenza. Proc. R. Soc. B, 274(1619), 1675-1684, 2007.
  • Moghadas S.M., M.E. Alexander, Bifurcations in an epidemic model with nonlinear incidence and infection-dependent removal rate. IMA Journal, Mathematical Medicine and Biology, 23(3), 231-254, 2006.
  • Alexander, M.E., A.R. Summers, and S.M. Moghadas. “Neimark–Sacker bifurcations in a non-standard numerical scheme for a class of positivity-preserving ODEs Proceedings of the Royal Society A, 462(2074) pp. 3167 – 3184, 2006.
  • M.E. Alexander, S.M. Moghadas, P. Rohani, and A.R. Summers, “Modelling the effect of a booster vaccination on disease epidemiology”, Journal of Mathematical Biology 52, pp. 290-306, 2006.
  • S.M. Moghadas and M.E. Alexander, “Bifurcation and numerical analysis of a generalized Gause-type predator-prey model”, Dynamics of Continuous, Discrete and Impulsive Systems, Series B, 13(5), pp. 533-554, 2006.
  • Alexander, M.E., "Tidal Resonances in Binary Star Systems", Monthly Notices of the Royal Astronomical Society, 227 (1987), pp. 843-861
  • Alexander, M.E., "Tidal Resonances in Binary Star Systems. II. Slowly Rotating Stars", Monthly Notices of the Royal Astronomical Society, 235 (1988), 1367-1383