\begin{table}%t1
\caption {\label{tab1}Numerical results.}
\tabcolsep 9pt
%\centerline
 {\begin{tabular}{cccccc} 
\hline\hline\\[-3mm]
Model & $\gamma$ & $m/H_{0}$ & $t_{0}$&$\frac{\Lambda(t_{\rm inf})}{\Lambda(t_{0})}$ 
&$\frac{\Lambda(t_{\rm pl})}{\Lambda(t_{0})}$\\ \hline 
$\Lambda$ & 0& 0 & 13.77&1&1\\
$\Lambda_{\gamma 0}$ & $0.004$& 0 &
13.82&$10^{102}$&$10^{124}$\\
$\Lambda_{0m}$ & 0& $2.4\times 10^{-3}$ &
13.75&$10^{51}$&$10^{63}$\\
$\Lambda_{\gamma m}$ & $0.004$&$2.8\times 10^{-3}$ &
13.80&$10^{102}$&$10^{124}$\\
\hline
\end{tabular}}
\par
\smallskip
The $1{\rm st}$ column 
indicates the vacuum model used; 
the last two rows correspond to the fine-tuning problem.
\end{table}