We analyze the data from narrow band H-alpha and forbidden O III CCD imaging of a sample of nearby spiral galaxies with active nuclei. The results show that the large scale star formation depends on the level of nuclear activity, with Seyfert 2 presenting the strongest disk and circumnuclear star formation, while Seyfert 1 shows very little. We

A sample of actively star forming H II galaxies has been observed in the radio continuum and several optical bands. These galaxies are currently undergoing very active star formation and have been selected on the basis of strong radio continuum emission. Most of the galaxies are irregular and have been associated with merger or interaction events

A search for stellar variability based on time resolved CCD observations for the open cluster NGC 6802, was conducted in June 1990 at the 2.5 Isaac Newton Telescope (INT), at the Observatorio del Roque de los Muchachos (ORM), La Palma, Canary Islands, Spain. The main goal of this kind of observations was the detection of p-modes in solar-like stars

We have derived the oxygen abundances of 50 F-type main-sequence stars, belonging to the Hyades open cluster, the Ursa Major group, and the field, using an NLTE analysis of the infrared triplet lines of O I at 7771-7775 AA. The stars of the middle F-range have previously been shown to exhibit a marked reduction in lithium abundance compared with

From high-resolution spectroscopy in the Li I λ67O.8 nm region of the double-lined detached eclipsing binary system EK Cepheid, we find a surface lithium abundance in the low-mass (1.12 M0) secondary of log N(Li)NLTE = 3.l±0.3, i.e., close to the present "cosmic" Li abundance. The abundances of Ca, Si and Fe, inferred from metallic lines in the

We present a procedure for associating statistical significances with the results of the likelihood analysis of the experiment of Davies et al. (1987) for the detection cosmic background radiation temperature fluctuations. This procedure allows us to say that a Chi-squared test which accounts for the correlation of the measurements is to be