Heather McCreadie, a researcher from GeoForschungsZentrum (GFZ) Potsdam, was invited to act as an external examiner for the PhD thesis defense of Jakub Velimsky, the internal PhD student of MAGMA Centre. The contribution of H. McCreadie to scientific discussion during the defense was important since her scientific interest has been mostly oriented to the collection, processing and analyzing geomagnetic data. These topics are less studied at our Department, and, hence, the discussions were inspiring not only for the future Jakub's work, but also for many of the other staff members and students.