Barium Abundances in Cepheids
  We derived the barium atmospheric abundances for a large sample of Cepheids, comprising 270 stars. The sample covers a large range of galactocentric distances, from about 4 to 15 kpc, so that it is appropriated to investigate the existence of radial barium abundance gradients in the galactic disc. In fact, this is the first time that such a comprehensive analysis of the distribution of barium abundances in the galactic disc is carried out. As a result, we conclude that the Ba abundance distribution can be characterized by a zero gradient. This result is compared with derived gradients for other elements, and some reasons are briefly discussed for the independence of the barium abundances upon galactocentric distances. 
S.M. Andrievsky, J.R.D. Lepine, S.A. Korotin, R.E. Luck, V.V.   Kovtyukh, W.J. Maciel
astro-ph.GA astro-ph.SR