Membranes and Fivebranes with Lower Supersymmetry and their AdS   Supergravity Duals
  We consider superconformal field theories in three and six dimensions with eight supercharges which can be realized on the world-volume of M-theory branes sitting at orbifold singularities. We find that they should admit a N=4 and N=2 supergravity dual in AdS_4 and AdS_7, respectively. We discuss the characteristics of the corresponding gauged supergravities. 
S. Ferrara, A. Kehagias, H. Partouche and A. Zaffaroni