On Log-concavity of the Generalized Marcum Q Function
  It is shown that, if nu >= 1/2 then the generalized Marcum Q function Q_nu(a, b) is log-concave in 0<=b <infty. This proves a conjecture of Sun, Baricz and Zhou (2010). We also point out relevant results in the statistics literature. 
Yaming Yu
math.ST cs.IT math.CA math.IT stat.TH