Relation between total acceleration and baryonic component for LSB and dwarf galaxies (Paolo et al. 2019). Acceleration deduced from the rotation curves of models QR1 and QR4 of Voglis et al. (2006) and Harsoula & Kalapotharakos (2009) assuming a half-mass radius of 3 kpc and a total mass of 10¹¹ M_⊙ for the galaxy. QR1 is taken as the reference for Keplerian rotation. The bifurcation between Keplerian rotation (QR1) and anomalous rotation (QR4) can be interpreted as a phase transition induced by the presence of substructures, i.e., spiral arms that have developed in model QR4.