  We investigate the effects of the Dzialoshinskii-Moriya (DM) and
Kaplan-Shekhtman-Entin-Wohlman-Aharony (KSEA) interactions on various
thermodynamic and magnetic properties of a spin 1/2 ladder. Using the Majorana
fermion representation, we derive the spectrum of low energy excitations for a
pure DM interaction and in presence of a superimposed KSEA interaction. We
calculate the various correlation functions for both cases and discuss how they
are modified with respect to the case of an isotropic ladder. We also discuss
the electron spin resonance (ESR) spectrum of the system and show that it is
strongly influenced by the orientation of the magnetic field with respect to
the Dzialoshinskii-Moriya vector. Implications of our calculations for NMR and
ESR experiments on ladder systems are discussed.
