model {
   for (i in 1:Num) {
      rt[i] ~ dbin(pt[i],nt[i]);
      rc[i] ~ dbin(pc[i],nc[i]);
      logit(pc[i]) <- mu[i];
      logit(pt[i]) <- mu[i] + delta[i];
      delta[i] ~ dt(d,tau,v);
      mu[i] ~ dnorm(0.0, 1.0E-5);
   }
   delta.new ~ dt(d,tau,v);
   d ~ dnorm(0.0,1.0E-6);
   tau ~ dgamma(1.0E-3,1.0E-3);
   sigma <- 1/sqrt(tau);

   for (n in 1:Nbins) {
      prior[n] <- 1/Nbins;   # Uniform prior on v
   }
   k ~ dcat(prior[]);               
   v <- eta[k];           # degrees of freedom for t
}