The paper “The two-process model for sleep-wake regulation: A nonsmooth dynamics perspective“, co-authored by Mustafa Sayli, Anne Skeldon, Rüdiger Thul, Rachel Nicks, and Stephen Coombes. Sayli, Thlua, Nicks, and Coombes are all members of the Centre for Mathematical Medicine and Biology (link here) at the University of Nottingham. A link to the published paper is here. The highlights of the paper are (a) nonsmooth dynamical systems techniques are used to shed light on the properties of the two-process model of sleep; (b) the power of saltation operators for describing the evoluton of perturbations in nonsmooth flows is emphasised; and (c) the Lyapunov exponent for the nonsmooth model is used to uncover the richness of its Arnol’d tongue structure. The paper forms part of Mustafa Sayli’s PhD thesis and follows up on work by Bailey, Derks, & Skeldon (blog link here). The image below shows the front page of the paper and Figure 6.