\begin{table}%t1
%\centering
\par
\caption{\label{tab1}Values of O/H implicit in the evolutionary tracks, in \cite{SSL01} grid and in this work for a given $Z$.}
\begin{tabular}{cccc}
\hline\hline \noalign{\smallskip}
$Z$ &O/H & Stasi{\' n}ska et~al. & This work\\
&(tracks)& (2001) & \\
\hline\noalign{\smallskip}
0.0004 &  --  & $1.70 \times 10^{-5}$&  -- \\
0.001  & $4.39\times 10^{-5}$ & -- & $2.46 \times 10^{-5}$\\
0.004  & $1.77\times 10^{-4}$ & $1.70 \times 10^{-4}$& $9.82 \times 10^{-5}$\\
0.008  & $3.64\times 10^{-4}$ & $3.40 \times 10^{-4}$& $1.96 \times 10^{-4}$\\
0.020  & $9.75\times 10^{-4}$ & $8.51 \times 10^{-4}$& $4.91 \times 10^{-4}$\\
0.040  & $2.12\times 10^{-3}$ & $1.70 \times 10^{-3}$& $9.82 \times
10^{-4}$\\
\hline
\end{tabular}
\end{table}