  In this talk I will present a complete theory for the behaviour of
large-scale dynamical heterogeneities in glasses. Following the work
arXiv:1001.1746 I will show that we can write a (physically motivated) simple
stochastic differential equation that is potentially able to explain the
behaviour of large scale dynamical heterogeneities in glasses. It turns out
that this behaviour is in the same universality class of the dynamics near the
endpoint of a metastable phase in a disordered system, as far as
reparametrization invariant quantities are concerned. Therefore Large scale
dynamical heterogeneities in glasses have many points in contact with the
Barkhausen noise. Numerical verifications of this theory have not yet done, but
they are quite possible.
