Transplanckian signatures in WMAP3?

In this note we investigate how a possible signal in the WMAP3 data of rapid oscillations in the primordial spectrum can be accommodated into an effective model of transplanckian physics including back reaction. The results, if due to a real effect, would indicate the presence of a low fundamental scale -- possibly the string scale -- around $2.2\cdot10^{-5}M_{pl}$.