A Concordance Method For Analyzing Categorical Time Series. An Application For The Search of Periodicities

Procedures for numerical analysis of circadian rhythms

“…In addition, the procedure is based solely on onset times, and, therefore, ignores most of the data in the time series. As alternatives, numerous numerical procedures for the determination of circadian period have been developed or adapted from general time series tools, including serial autocorrelation (Eijzenbach et al 1986;Halberg 1960;Hassnaoui et al 2000;Lumineau et al 1998;Mormont et al 2000), inter-onset averaging (Albers et al 1981;Diambra et al 2002;Rao & Sharma 2002), iterative harmonics (Klemfuss & Clopton 1993), acrophase counting (Refinetti 1991), singular value decomposition (Kanjilal et al 1999), and nonlinear multiple components analysis (Alonso & Fernández 2001;Halberg 1980;Rummel et al 1974), culminating in linear-nonlinear rhythmometry (Halberg 1980). In the case of a single component, a confidence interval for the period estimate obtained by the three periodogram procedures discussed above (the Fourier periodogram, the Enright period-ogram, and the Lomb -Scargle periodogram) can be determined by the intersection of the chosen level of significance with the envelope of the periodogram around the peak, as outlined in Bingham et al (1984) for the cosinor.…”