The distribution of stellar abundances along the Galactic disk is an important constraint for models of chemical evolution and Galaxy formation .
In this study we derive radial gradients of C , N , O , Mg , Al , Si , as well as S , from abundance determinations in young OB stars .
Our database is composed of a sample of 69 members of 25 open clusters , OB associations and H II regions with Galactocentric distances between 4.7 and 13.2 kpc .
An important feature of this abundance database is the fact that the abundances were derived self-consistently in non-LTE using a homogeneous set of stellar parameters .
Such an uniform analysis is expected to reduce the magnitude of random errors , as well as the influence of systematics in the gradients defined by the abundance and Galactocentric distance .
The metallicity gradients obtained in this study are , in general , flatter than the results from previous recent abundance studies of early-type stars .
The slopes are found to be between -0.031 ( for oxygen ) and -0.052 { dex kpc ^ { -1 } } ( for magnesium ) .
The gradients obtained for the studied elements are quite similar and if averaged , they can be represented by a single slope of -0.042 \pm 0.007 { dex kpc ^ { -1 } } .
This value is generally consistent with an overall flattening of the radial gradients with time .