Periodic forcing of nonlinear oscillators leads to a large number of dynamic behaviors. The coupling of the cell-cycle to the circadian clock provides a biological realization of such forcing. Using highthroughput single-cell microscopy, we have studied the correlations between cell cycle duration in discrete lineages of several different organisms including those with known coupling to a circa...

V̇ O2 and V̇CO2 measurements are central to methods for assessment of physical fitness and endurance capabilities in athletes. As measuring V̇ O2 and V̇CO2 is difficult outside a lab, models with good prediction properties are necessary for online analysis and modeling in the field. Easier to measure are heart rate and during cycling also power. Thus, the here described models are based on either o...

To date, multiple strategies have been proposed for the estimation of speakers’ physical parameters such as height, weight, age, gender etc. from their voices. These employ various types of feature measurements in conjunction with different regression and classification mechanisms. While some are quite effective for adults, they are not so for children’s voices. This is presumably because in ch...

Heart rate variability (HRV) exhibits fluctuations characterized by a power law behavior of its power spectrum. The interpretation of this nonlinear HRV behavior, resulting from interactions between extracardiac regulatory mechanisms, could be clinically useful. However, the involvement of intrinsic variations of pacemaker rate in HRV has scarcely been investigated. We examined beating variabil...

Recently, it has been proposed a new method to investigate the linear/nonlinear properties of a time series by decomposing it into two sub-series: magnitude and sign sub-series (Ashkenazy et al., 2003). The long-range correlation properties of the magnitude and sign sub-series relate to nonlinear and linear behavior of the original time series respectively. We apply this method to the hourly ti...

We present a biophysical model of saccade initiation based on competitive integration of planned and reactive cortical saccade decision signals in the intermediate layer of the superior colliculus. In the model, the variable slopes of the climbing activities of the input cortical decision signals are produced from variability in the conductances of Na, K, Ca activated K, NMDA and GABA currents....

We formulate equations for the slow time dynamics of fluid motion that self consistently account for the effects of the variability upon the mean. The time-average effects of the fluctuations introduce nonlinear dispersion that acts to spatially smooth the transport velocity of the mean flow relative to its circulation or momentum velocity, by the inversion of a Helmholtz operator whose length ...

Linear dimensionality reduction techniques, notably principal component analysis, are widely used in climate data analysis as a means to aid in the interpretation of datasets of high dimensionality. These linear methods may not be appropriate for the analysis of data arising from nonlinear processes occurring in the climate system. Numerous techniques for nonlinear dimensionality reduction have...

S Schema Theory (1975) predicts that successful motor skill learning and performance are largely determined by the amount of movement variability the performer experiences during practice. This prediction has been consistently validated through a vast amount of research. Within a training environment, practice variability can be integrated by creating variation within the movements of an action...

This work explores basic properties of the size and growth rates distributions of firms at the aggregate and disaggregate levels. Using an extensive dataset on French manufacturing firms, we investigate which properties of firm size distributions and growth dynamics characterize the aggregate dynamics and are, at the same time, robust under disaggregation. Our analysis is based on non-linear ro...