(3+1)-spectrum of neutrino masses: A chance for LSND?

The (3+1)-scheme in which the fourth (predominantly sterile) neutrino is isolated from a block of three flavour neutrinos by the mass gap Δm2LSND ∼ (0.4 - 10) eV2 is revisited in the light of evidence that the atmospheric (νμ → ντ) and the solar neutrino oscillations (νe → νμ/ντ) are dominantly active to active neutrino transitions, as is indicated by recent data. In this framework, I revisited the (3+1)-scheme and I find that the LSND result can be reconciled with existing bounds on νe- and νμ - disappearance at 95 - 99% C.L.