  A characteristic feature of the non--equilibrium dynamics of real spin
glasses at low temperatures are strong aging effects. These phenomena can be
manipulated by changing the external parameters in various ways: a
thermo-cycling experiment consists for instance of a short heat pulse during
the waiting time, by which the relaxation might be strongly affected. Results
of numerical experiments of this kind, performed via Monte Carlo simulations of
the three dimensional Ising spin glass model, are presented. The theoretical
implications are discussed and the scenario found is compared with the
experimental situation.
