We give a short Lie-derivative theoretic proof of the following recent result of Barros et al. “A compact non-trivial almost Ricci soliton with constant scalar curvature is gradient, and isometric to a Euclidean sphere”. Next, we obtain the result: a complete almost Ricci soliton whose metric g is K-contact and flow vector field X is contact, becomes a Ricci soliton with constant scalar curvature. In particular, for X strict, g becomes compact Sasakian Einstein.
Sharma, Ramesh, "Almost Ricci Solitons and K-Contact Geometry" (2014). Mathematics Faculty Publications. 4.
Almost Ricci solitons and K-contact geometry, Monatshefte fur Mathematik 175(4) (Dec. 2014),621-628. First published online 04 July 2014