0.52 respectively.

We attempt once more to put the abundance measurements onto a common scale by considering the $gf$ values used by the various studies to which we compare our abundances. The element we focus upon is Zr (in order to compare \[Rb/Zr\] between the samples). We shift all the Zr abundances onto the @smith00 scale in order to compare with their theoretical predictions for \[Rb/Zr\] from low and intermediate-mass AGBs (their Figure 14). (Our Rb abundances were already on the Smith scale.) Abundance measurements for Zr are complicated by the fact that the laboratory Zr $gf$ values from @zr are smaller than the solar $gf$-values by 0.41 dex [@tomkin99]. We must therefore take care and account for both the adopted solar abundance and the $gf$ value. @smith00 adopt the @zr $gf$-values and a solar abundance log $\epsilon_\odot$(Zr) = 2.90. We used the @zr $gf$-values and a solar abundance log $\epsilon_\odot$(Zr) = 2.60 [@grevesse98]. Therefore we adjust our Zr abundances by $-$0.30 dex to ensure that we are on the same scale as @smith00. Similarly, we adjust the Zr abundances of @gratton94 and @abia01 by $-$0.30 dex since they adopt the same $gf$ values and a very similar solar abundance 