We have performed a detailed oxygen abundance analysis of 23 metal-poor (-3.0 [Fe/H] -0.3) unevolved halo stars and one giant through the OH bands in the near UV, using high-resolution echelle spectra. Oxygen is found to be overabundant with respect to iron in these stars, with the [O/Fe] ratio increasing from 0.6 to 1 between [Fe/H] = -1.5 and

The authors review the multifrequency behaviour of the so-called non-magnetic cataclysmic variables (NMCVs) after having discussed the classification of the CVs following different known approaches. They remark some open questions and give some new inputs for a faster and more general development of the studies of such binary systems in which the

The authors present the first results of their multicolor polarimetric study of stars in the association Ara OB1. Stars belonging to the clusters NGC 6204, NGC 6193, NGC 6167, and the local field were observed as part of a global study of the region. The polarimetry shows that the orientation of the polarimetric vectors of member stars are very

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