We report the results of a high-resolution spectroscopic survey of all the stars more luminous than M_V = 6.5 mag within 14.5 pc from the Sun. The Hipparcos catalog's completeness limits guarantee that our survey is comprehensive and free from some of the selection effects in other samples of nearby stars. The resulting spectroscopic database

Not Available

We confirm the planetary nebula nature of two sources: PN G000.2+06.1 and PN G002.3+02.2, previously identified by Terzan in a photometric survey toward the Galactic center as objects possibly belonging to this class. Optical images taken in Hα reveal the extended morphology of the nebulae, while spectroscopic observations allow us to determine

We report the results of a non-LTE Fe, O and Mg abundance analysis of the carbon-nitrogen-rich ultra-metal-poor giants CS 29498-043 and CS 22949-037. The abundance of oxygen has been derived from measurements of the oxygen triplet at 7771-5 Å in high resolution spectra obtained with KeckI/HIRES and the forbidden line [O I] 6300 Å detected in the

We have analysed the morphology, kinematics, colors and chemical composition of the ionized gas of the different objects belonging to the interacting compact group HCG 31 in order to get a global view of the origin and evolution of the dwarf galaxies present in it.

Quantum fluctuations generate in three-dimensional gauge theories not only radiative corrections to the Chern-Simons coupling but also non-analytic terms in the effective action. We review the role of those terms in gauge theories with massless fermions and Chern-Simons theories. The explicit form of non-analytic terms turns out to be dependent on