  To overcome the difficulties with the energy indefiniteness in field theories
with higher derivatives, it is supposed to use the mechanical analogy, the
Timoshenko theory of the transverse flexural vibrations of beams or rods well
known in mechanical engineering. It enables one to introduce the notion of a
"mechanical" energy in such field models that is wittingly positive definite.
This approach can be applied at least to the higher derivative models which
effectively describe the extended localized solutions in usual first order
field theories (vortex solutions in Higgs models and so on). Any problems with
a negative norm ghost states and unitarity violation do not arise here.
