P. Achermann

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A new algorithm for the detection of oscillatory events in the EEG is presented. By estimating autoregressive (AR) models on short segments the EEG is described as a superposition of harmonic oscillators with damping and frequencies varying in time. Oscillatory events are detected, whenever the damping of one or more frequencies falls below a predefined(More)
The objective of the present investigation is to assess the baseline mortality-adjusted 10-year survival of rectal cancer patients. Ten-year survival was analyzed in 771 consecutive American Joint Committee on Cancer (AJCC) stage I–IV rectal cancer patients undergoing open resection between 1991 and 2008 using risk-adjusted Cox proportional hazard(More)
Several investigators of EEG time series reported a rejection of the null hypothesis of linear stochastic dynamics for epochs longer than 10 s. We examine whether this rejection is related to nonlinearity or to nonstationarity. Our approach is a combination of autoregressive modeling and surrogate data testing. It is shown that the fraction of subsegments,(More)
It has been shown previously in Djungarian hamsters that the initial electroencephalography (EEG) slow-wave activity (power in the 0.5-4.0 Hz band; SWA) in non-rapid eye movement (NREM) sleep following an episode of daily torpor is consistently enhanced, similar to the SWA increase after sleep deprivation (SD). However, it is unknown whether the network(More)
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