Non-local rheology in dense granular flows - Revisiting the concept of fluidity Mehdi Bouzid, Adrien Izzet, Martin Trulsson, Eric Clément, Philippe Claudin and Bruno Andreotti Eur. Phys. J. E, 38 11 (2015) 125 Published online: 30 November 2015 DOI: 10.1140/epje/i2015-15125-1