\begin{table}%T6
      \caption{\label{tab:molecule-ratios}Line intensity ratios between molecules.}
         \small
	%\centerline
{
         \begin{tabular}{lccc}
            \hline\hline
            \noalign{\smallskip}
            Molecules &  & Transition$^{{a}}$ & \\
                      & $J=1{-}0$ & $J=3{-}2$ & $J=4{-}3$ \\ 
            %\noalign{\smallskip}
            \hline
            \noalign{\smallskip}
	    $\frac{\rm HNC}{\rm HCN}$ & 0.71~$\pm$~0.45 & 0.26~$\pm$~0.08 & 0.16~$\pm$~0.05 \\
            \noalign{\smallskip}
            $\frac{\rm CN}{\rm HCN}$ & 0.89~$\pm$~0.69 & 0.54~$\pm$~0.15 & 0.14~$\pm$~0.04 \\ 
            \noalign{\smallskip}
            $\frac{\rm HCO^+}{\rm HCN}$ & 1.10~$\pm$~0.59 & 0.13~$\pm$~0.04 & 0.36~$\pm$~0.10 \\ 
            \noalign{\smallskip}	    	    
            \hline
         \end{tabular}}
\smallskip
$^{{a}}$ The lines correspond to $J=1{-}0$, $J=3{-}2$ and $J=4{-}3$, 
for HCN, HNC and \hcop. In the case of CN, the lines are actually 
$N_J=1_{3/2}{-}0_{1/2}$, $N_J=2_{5/2}{-}1_{3/2}$ and $N_J=3_{5/2}{-}2_{5/2}$, respectively.
\end{table}