2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/118724We present recent data of electric signals detected at the Earth's surface, which confirm the earlier finding [Phys. Rev. E 73, 031114 (2006)] that the value of the entropy in natural time as well as its value under time reversal are smaller than that of the entropy of a ``uniform'' distribution. Furthermore, we show that the scale dependence of the fluctuations of the natural time itself under time reversal provides a useful tool for the discrimination of seismic electric signals (critical dynamics) from noises emitted from manmade sources as well as for the determination of the scaling exponent.4 pages including 3 figuresStatistical MechanicsSoft Condensed Mattertext