Institute for Complex Systems and Mathematical Biology, Physics Department, University of Aberdeen, Aberdeen, UK.|Université Montpellier 2, Laboratoire Charles Coulomb UMR 5221, Montpellier, France.|Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK.|Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK.|Institute for Complex Systems and Mathematical Biology, Physics Department, University of Aberdeen, Aberdeen, UK.