In the linear case statistical independence is a sufficient criterion for performing blind source separation. In the nonlinear case, however, it leaves an ambiguity in the solutions that has to be resolved by additional criteria. Here we argue that temporal slowness complements statistical independence well and that a combination of the two leads to unique solutions of the nonlinear blind sourc...

Gait hypokinesia (slowness) is a characteristic feature of Parkinson's disease. It is not clear, however, whether the slowness is due to a problem in regulation of the timing of consecutive steps or the control of stride size. Examination of cadence control for slow to medium walking speeds has shown an increase in step frequency that was a compensation for reduced stride length. In this invest...

Previous formulations of coda wave interferometry make it possible to assess the average change of the medium, but they do not allow for the spatial localization of this change (Snieder et al., 2002; Snieder, 2002). We present an approach for localizing temporal changes in the medium using strongly scattered waves, and test it with numerical models for 2D scalar waves. Using an integral represe...

Three examples of the inversion of refraction data by downward continuation illustrate the applicability of the method to field data. The first example is a refraction profile from the Mojave Desert, California. These data are spatially aliased and contain clear evidence of lateral inhomogeneity. The inversion in this case produces a broken image in the slowness-depth domain due to the lateral ...

Slowness of thought is not necessarily a handicap but could be a signature of optimal brain function. Emerging evidence shows that neuroanatomical and dynamical constraints of the human brain shape its functionality in optimal ways, characterized by slowness during task-based cognition in the context of spontaneous resting-state activity. This activity can be described mechanistically by whole-...