Mass fraction produced by the s-process channel of production (top panels) and [X/Fe] vs [Fe/H] (bottom panels) for Zr (left panels), Ba (central panels) and La (right panels) for models with different IRV distribution and Kroupa et al. (1993) IMF. Results are shown for models adopting the reference IRV distribution (R150, thick solid lines), R300 distribution (thin dashed), DIS2 distribution (thin dash-dotted) and DIS3 distribution (thin dotted). Data are as in Fig. 8.