\begin{table}%a.1
%\centering
\par
  \caption{List of symbols.}
  \begin{tabular}{lp{6cm}}
  \hline \hline
  $\Delta  {v}$     &   relative velocity\\
  $\Sigma$                &   surface density\\
  $\Omega$                &   angular (Keplerian) rotation frequency\\
  $A$                     &   \changed{geometrical} cross-section (1 particle)\\
  $C$                     &   collision rate \\
  $E$                     &   collision energy \\
  $E_{\rm restr}/E_{\rm max-c}/E_{\rm frag}$  & \changed{energy limits for particle restructuring/ maximum-compression/ fragmentation} \\
  $H_{\rm g}/h$        &   gas/particle scale height \\
  $K$                     &   collision kernel \\
  $N$                     &   number of monomers (Sect.\ \ref{sec:model}); number of particles (Sect.\ \ref{sec:mccode}) \\
  $N_{\rm c}$          &   number of contacts\\
  \changed{$N_{\rm s}$} &   \changed{number of distinct particles (number of species)}\\
  $R$                     &   heliocentric radius\\
   Re                     &   Reynolds number\\
  $T$                     &   temperature\\
  $V/{\cal V}$            &   particle/simulated volume \\
  $\alpha_{\rm T}$     &   turbulent viscosity parameter \\
  $\xi$                   &   critical displacement \\
  $\gamma$                &   specific surface energy \\
  $\delta$                &   area-mass exponent ($A\sim m^\delta$) in fractal regime  \\
  $\kappa$                &   number of coagulations\\
  $\mu$                   &   reduced mass\\
  $\nu_{\rm m}/\nu_{\rm T}$ &   molecular/turbulent viscosity\\
  $\psi$                  &   \changed{enlargement parameter} \\
  $\rho_{\rm d}/\rho_{\rm g}/\rho_{\rm s}$  & dust/gas/specific density \\ 
  $\sigma$                &   \changed{collision} cross-section \\
  $\tau_{\rm f}$       &   friction time \\
  $\tau_{\rm rain}$    &   \changed{friction time at which particles are removed from simulation due to rain-out}\\
  $a/a_0$                 &   radius (size)/monomer size \\
  $c_{\rm g}$          &   thermal sound speed\\
  $g_i$                   &   number population of species $i$.\\
  $k_{\rm B}$          &   Boltzmann constant \\
  $\ell$                  &   eddy length scale\\
  $m$                     &   mass \\
  $f$                     &   particle distribution function (number density spectrum) \\
  $r$                     &   random deviate \\
  $t$                     &   time \\
  $t_{\rm s}/t_0$               &   \changed{turn-over timescale of smallest/largest eddy} \\
  $ {v}$	&   velocity \\
  $ {v_{\rm s}}/{v_0}$ & \changed{velocity smallest/largest eddies} \\
  \hline
   \end{tabular}
\end{table}