\begin{table}%t1
%\centering
\par
\caption{\label{models}The nucleosynthesis prescriptions and IMFs adopted for the 4 models.}
\begin{tabular}{ccc}
\hline\hline
Model&  IMF      &      yields \\
\hline 
A & ``top heavy'' (Model 2) & ``total yields'' (Model a)\\  
B & ``top heavy'' (Model 2)& ``wind yields'' (Model b)  \\ 
C & ``standard'' (Model 1) & ``total yields'' (Model a) \\
D & ``standard '' (Model 1) & ``wind yields''  (Model b) \\
\hline
\end{tabular}
\end{table}