The Evolution of Embedded Small Clusters
  A young open cluster is a 2-phase system: an ensemble of stars move in a gaseous medium (the mother molecular cloud). The dynamics and thermodynamics of the system, and so its evolution and final fate (is it stable or unstable?), strongly depends on the mutual feedback between gas and stars. We present an approach which consists in a (simplified) model where stars (N-bodies) move within a gaseous spherical molecular cloud. The two components influence each other through gravity and mass loss. Among other results (role of IMF, SFE, stellar background, etc.), we find that a significant fraction of small clusters can be destroyed even before SN explosion. when a significant amount of massive stars are present. 
R. Capuzzo-Dolcetta, F. Sori (Inst. of Astr., Roma)