model{
  for( i in 1:n ){
  y[i]  ~ dbin( p[i], 1)
  logit( p[i] ) <- beta[1] + beta[2] * temp[i]
  }
  for( j in 1:2 ){
  ptilde[j]  ~ dbeta( a[j], b[j] )
  }
  beta[1] <- (75/20) * logit( ptilde[1] )
                 - (55/20) * logit( ptilde[2] )
  beta[2] <- (-1/20) * logit( ptilde[1] )
                 + (1/20) * logit( ptilde[2] )}