model
   {
      for( i in 1 : N ) {
         y[i] ~ dnorm(mu[i], tau)
         mu[i] <- lambda[T[i]]
         T[i] ~ dcat(P[])
      }   
      P[1:2] ~ ddirch(alpha[])
      theta ~ dnorm(0.0, 1.0E-6)I(0.0, )
      lambda[2] <- lambda[1] + theta
      lambda[1] ~ dnorm(0.0, 1.0E-6)
      tau ~ dgamma(0.001, 0.001) sigma <- 1 / sqrt(tau)
   }