CHICAGO (Standard&Poor's) Feb. 28, 2011--Standard&Poor's Ratings Services has assigned its 'SP-1' short-term rating to Michigan Finance Authority's $75 million series 2011A-1 state aid revenue notes and $156 million series 2011A-2 state aid revenue notes, issued for Detroit Public Schools. At the same time, Standard&Poor's affirmed its 'SP-1' short-term rating on the authority's series 2010B and 2010E state aid revenue notes, issued for Detroit Public Schools. The 'SP-1' rating is based on the following credit factors: A pledge of all state aid to be appropriated by the state of Michigan to Detroit Public Schools starting with fiscal 2012; The limited risk, in Standard&Poor's view, that the state will have substantial delays in state