A recent article published in the Monthly Notices of the Royal Astronomical Society, led by Dr. Kostas Kouroumpatzakis, of the Institute of Astrophysics at the Foundation for Research and Technology, Hellas (IA-FORTH), and the University of Crete, provides new insights into the connection between the X-ray luminosity of accreting black holes and neutron stars and the composition of the stellar populations they are associated with. This research was conducted at the Institute of Astrophysics of FORTH and the University of Crete.