Effective Temperature of Red Blood Cell Membrane Fluctuations
  Biologically driven non-equilibrium fluctuations are often characterized by their non-Gaussianity or by an "effective temperature", which is frequency dependent and higher than the ambient temperature. We address these two measures theoretically by examining a randomly kicked "particle", with a variable number of kicking "motors", and show how these two indicators of non-equilibrium behavior can contradict. Our results are compared with new experiments on shape fluctuations of red-blood cell membranes, and demonstrate how the physical nature of the motors in this system can be revealed using these global measures of non-equilibrium. 
Eyal Ben-Isaac, YongKeun Park, Gabriel Popescu, Frank L.H. Brown, Nir   S. Gov and Yair Shokef
physics.bio-ph cond-mat.soft cond-mat.stat-mech