Quark-Hadron Duality in Structure Functions
  Quark-hadron duality is studied in a systematic way for both the unpolarized and polarized structure functions, by taking into account all the available data in the resonance region.In both cases, a detailed perturbative QCD based analysis of the structure functions integrals in the resonance region is performed: non perturbative contributions are disentangled, and higher twist terms are evaluated. A different behavior between the unpolarized and polarized structure functions at low Q^2 is found. 
A. Fantoni, N. Bianchi and S. Liuti