Congratulations to Imran Usmani for passing his PhD viva today (Friday 8 July). The thesis title is “Parametric models of the circadian pacemaker in controlled lighting conditions“, and the examiners were Prof Victoria Booth (Michigan) and Prof Gianne Derks. Imran‘s supervisors are Prof Anne Skeldon and Prof Derk-Jan Dijk (Director, Surrey Sleep Research Centre). Figure credit: Wikipedia page on circadian rhythms