  Inspired by the tachyon-free non-supersymmetric heterotic SO(16)xSO(16)
string we consider a special class of non-supersymmetric field theories: Those
that can be obtained from supersymmetric field theories by supersymmetry
breaking twists. We argue that such theories, like their supersymmetric counter
parts, may still possess some fermionic symmetries as left-overs of the super
gauge transformations and have special one-loop non-renormalization properties
due to holomorphicity. In addition, we extend the supergraph techniques to
these theories to calculate some explicit supersymmetry-breaking corrections.
