model
{

wtot0 ~ dbin(p0, n0)
wtot1 ~ dbin(p1, n1)

p0 <- r0*SN + (1-r0)*(1-SP)
p1 <- r1*SN + (1-r1)*(1-SP)

lor <- logit(r1) - logit(r0)

### priors

r0 ~ dunif(0,1)
r1 ~ dunif(0,1)
SN ~ dbeta(a.sn, b.sn)
SP ~ dbeta(a.sp, b.sp)


}