On the global triggering mechanism of star formation in galaxies
  We study the large-scale triggering of star formation in galaxies. We find
that the largest mass-scale not stabilized by rotation, a well defined quantity
in a rotating system and with clear dynamical meaning, strongly correlates with
the star formation rate in a wide range of galaxies. We find that this relation
can be explained in terms of the threshold for stability and the amount of
turbulence allowed to sustain the system in equilibrium. Using this relation we
also derived the observed correlation between the star formation rate and the
luminosity of the brightest young stellar cluster.
