  In order to verify the effects of the most recent data on the evolution of
Carina and Sagittarius Dwarf Spheroidal Galaxies (dSph) and to set tight
constraints on the main parameters of chemical evolution models, we study in
detail the chemical evolution of these galaxies through comparisons between the
new data and the predictions of a model, already tested to reproduce the main
observational constraints in dSphs. Several abundance ratios, such as
[$\alpha$/Fe], [Ba/Fe] and [Eu/Fe], and the metallicity distribution of stars
are compared to the predictions of our models adopting the observationally
derived star formation histories in these galaxies. These new comparisons
confirm our previously suggested scenario for the evolution of these galaxies,
and allow us to better fix the star formation and wind parameters. In
particular, for Carina the comparisons indicate that the best efficiency of
star formation is $\nu = 0.15 Gyr^{-1}$, that the best wind efficiency
parameter is $w_i$ = 5 (the wind rate is five times stronger than the star
formation rate), and that the star formation history, which produces the best
fit to the observed metallicity distribution of stars is characterized by
several episodes of activity. In the case of Sagittarius our results suggest
that $\nu=3 Gyr^{-1}$ and $w_i=9$, again in agreement with our previous work.
Finally, we show new predictions for [N/Fe] and [C/Fe] ratios for the two
galaxies suggesting a scenario for Sagittarius very similar to the one of the
solar vicinity in the Milky Way, except for a slight decrease of [N/Fe] ratio
at high metallicities due to the galactic wind. For Carina we predict a larger
[N/Fe] ratio at low metallicities, reflecting the lower star formation
efficiency of this galaxy relative to Sagittarius and the Milky Way.
