  Experimental evidence has recently put the validity of the Porter-Thomas
distribution (PTD) for partial neutron widths into question. We identify two
terms in the effective Hamiltonian that violate orthogonal invariance (the
basis for the PTD). Both are due to the coupling to the decay channels. We show
that realistic estimates for the coupling to the neutron channel and for
non-statistical gamma decays yield significant modifications of the PTD.
