In this contribution we present our on-going project about the understanding of the evolution of galactic OB associations and the implications on the global understanding of massive star evolution. Galactic OB associations are the ideal laboratory for testing our current knowledge about the stellar and chemical evolution, and the interaction of

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We use Hα measurements of complete sets of HII regions in disc galaxies to compute the fraction of ionizing photons which escape from them using the hypothesis of density bounding. The escaping flux is more than enough to ionize the observed diffuse ionized gas (DIG) and the balance implies that an important fraction of the flux escapes into the

The influence of gravitational microlensing on the X-ray spectral line profiles originated from a relativistic accretion disc has been studied. Using a disc model, we show that microlensing can induce noticeable changes in the line shapes when the Einstein ring radius associated with the microlens is of a size comparable to that of the accretion

During 1996 and 1997, the Canary Island Observatories' `International Time' project on Barred Galaxies obtained photometric images in broad- and narrow-band, and intermediate to high spectral resolution spectra in the optical and near IR of a selected set of a dozen barred galaxies. For some of these, 2D H_α kinematics was also obtained. The

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