  We consider the Standard Model extended by a heavy scalar singlet in
different regions of parameter space and construct the appropriate low-energy
effective field theories up to first nontrivial order. This top-down exercise
in effective field theory is meant primarily to illustrate with a simple
example the systematics of the linear and nonlinear electroweak effective
Lagrangians and to clarify the relation between them. We discuss power-counting
aspects and the transition between both effective theories on the basis of the
model, confirming in all cases the rules and procedures derived in previous
works from a bottom-up approach.
