  We take a fresh look at the abundance of nitrogen in DLAs with oxygen
abundances between 1/10 and 1/100 of solar. This is a metallicity regime poorly
sampled in the local universe and where QSO absorbers may hold clues to both
the nucleosynthetic origin of N and the chemical evolution of high redshift
galaxies. We combine new VLT UVES observations with others from the literature
to form a sample of 10 DLAs in which the abundances of N and of one of the two
alpha-capture elements O or S have been measured. We confirm earlier reports
that the (N/O) ratio exhibits a larger range of values than other ratios of
heavy elements in DLAs; however, all 10 DLAs fall in the region of the (N/O)
vs. (O/H) plot delimited by the primary and secondary levels of nitrogen
production. Our results provide empirical evidence in support of the proposal
that intermediate mass stars (with masses less than 7 solar masses) are the
main source of primary nitrogen, so that its release into the ISM lags behind
that of oxygen, which is produced by Type II SNae. A high proportion (40%) of
the DLAs in our sample have apparently not yet attained the full primary level
of N enrichment; this finding may be an indication that the metallicity regime
we are studying preferentially picks out galaxies which have only recently
condensed out of the IGM and begun forming stars. Alternatively, the delay in
the release of N following an episode of star formation may increase with
decreasing metallicity, if stars of progressively lower masses than 4 solar
masses can synthesize N in their hotter interiors.
