The Maximization of Mean Vector Length for the Identification of Unknown Periods in Biological Rhythms: An Extension to Continuous Variables

Abstract

In a recent paper Rocchi and Ghiandoni proposed the maximization of mean vector length as a circular statistics tool for the preliminary identification of unknown and unforeseeable periods in biological rhythms, but its application was limited to unitless data. In this paper an extension of the method to the case of continuous variables collected at equidistant time intervals is proposed. The extended method is proposed as an exploratory tool in the analysis of chronobiological data. Two different examples of the application of this method (to edible white truffle harvesting data and to TSH level data) are also included and compared with the Fourier spectral analysis.