Break frequencies f_b,n and f_b,B obtained from fits relative to (a) ﹩{f}_{{d}_{e}}﹩ and (b) ﹩{f}_{{\rho }_{e}}﹩. (c) Mean trend of the normalized n–B spectral ratio as a function of ﹩f/{f}_{{d}_{e}}﹩. Violet shaded regions indicate the standard deviation (σ) across the intervals. The mean ﹩{f}_{{\rho }_{e}}﹩ and its variation are shown by the red marker.