pan> <span class='kw'>=</span> <span class='kw'>NULL</span>,
  <span class='kw'>zeta_mean</span> <span class='kw'>=</span> <span class='kw'>NULL</span>,
  <span class='kw'>zeta_sd</span> <span class='kw'>=</span> <span class='kw'>NULL</span>,
  <span class='kw'>eta_mean</span> <span class='kw'>=</span> <span class='kw'>NULL</span>,
  <span class='kw'>eta_sd</span> <span class='kw'>=</span> <span class='kw'>NULL</span>,
  <span class='kw'>psi_mean</span> <span class='kw'>=</span> <span class='kw'>NULL</span>