Diminished vagal activity and blunted circadian heart rate dynamics in posttraumatic stress disorder assessed through 24-h linear and unifractal analysis by Agorastos Agorastos, Oliver Stiedl, Judith A. Boel, Pia S. Heppner, Torben Hager, Tobias Moeller-Bertram, Uzair Haji, Arame Motazedi, Dewleen G. Baker