\begin{table}%t4
  \caption{Mean core abundance variations during MS of the
    60~\Ms{}~models. $\del{X}$ refers to the amplitude (in~dex) of variation of
    element~$X$. For NGC~6752 it refers to the amplitude variation observed 
    between polluted and unpolluted stars.}
  \label{tab:cen}
  %\centering
\small
  \begin{tabular}{ccccccc}
    \hline \hline
    Model & $\del{C}$ & $\del{N}$ &$\del{O}$ &$\del{Na}$ &$\del{Mg}$
    &$\del{Al}$  \\
    \hline
    NGC~6752 & --0.7 & 1.7 & --1.0 & 0.9 & --0.3 & 1.4 \\
    \hline
    60rA     & --0.9 & 1.5 & --1.8 & 1.6 & 0.5  & 0.7 \\
    60rB     & --0.9 & 1.5 & --1.8 & 1.6 & 0.0  & 0.7 \\
    60rC     & --0.9 & 1.5 & --1.8 & 1.0 & --0.1 & 0.7 \\
    60rD     & --0.9 & 1.5 & --1.8 & 1.0 & --0.4 & 1.3 \\
    \hline
  \end{tabular}
\end{table}