  For nonsupersymmetric theories, the one-loop effective action can be computed
via zeta function regularization in terms of the functional trace of the heat
kernel associated with the operator which appears in the quadratic part of the
action. A method is developed for computing this functional trace by exploiting
its similarity to a Gaussian integral. The procedure is extended to superspace,
where it is used to compute the low energy effective action obtained by
integrating out massive scalar supermultiplets in the presence of a
supersymmetric Yang-Mills background.
