An RNA foldability metric; implications for the design of rapidly   foldable RNA sequences
  Evidence is presented suggesting, for the first time, that the protein foldability metric sigma=(T_theta - T_f)/T_theta, where T_theta and T_f are, respectively, the collapse and folding transition temperatures, could be used also to measure the foldability of RNA sequences. The importance of sigma is discussed in the context of the in silico design of rapidly foldable RNA sequences. 
W. Ndifon and A. Nkwanta