  We report results on the formation of disk-like structures in two
cosmological hydrodynamical simulations in a hierarchical clustering scenario,
sharing the same initial conditions. In the first one, a simple and generic
implementation of star formation has allowed galaxy-like objects with stellar
bulges and extended, populated disks to form. Gas in the disk comes from both,
particles that survive mergers keeping in part their angular momentum content,
and new gas supply by infall, once the merger process is over, with global
specific angular momentum conservation. The stellar bulge forms from gas that
has lost most of its angular momentum. In the second simulation, no star
formation has been included. In this case, objects consist of an overpopulated
central gas concentration, and an extended, underpopulated disk. The central
concentration forms from particles that suffer an important angular momentum
loss in violent events, and it often contains more than 70% of the object's
baryonic mass. The external disk forms by late infall of gas, that roughly
conserves its specific angular momentum. The difference between these two
simulations is likely to be due to the stabilizing character of the stellar
bulge-like cores that form in the first simulation, which diminishes the inflow
of gas triggered by mergers and interactions.
