Sterile Plus Active Neutrinos and Neutrino Oscillations

Using a 3 + 1 neutrino model with one sterile and the three standard active neutrinos with a 4x4 unitary transformation matrix, U, relating flavor to mass neutrino states, the probability of $\nu_\mu$ to $\nu_e$ transition is estimated using sterile-active neutrino masses determined by MiniBooNE and other experiments and sterile-active neutrino angles in the 4x4 U matrix.