  In the present paper we report on first results of a project in Brussels
where we study the effects of stellar dynamics on the evolution of young dense
stellar systems using the 3 decades expertise in massive star evolution and our
population (number and spectral) synthesis code. We highlight an
unconventionally formed object scenario (UFO-scenario) for Wolf Rayet binaries
and study the effects of a luminous blue variable-type instability wind mass
loss formalism on the formation of intermediate mass black holes.
