Controlled mechanical ventilation is characterized by a fixed breathing frequency and tidal volume. Physiological and mathematical models have demonstrated the beneficial effects of varying tidal volume and/or inspiratory pressure during positive-pressure ventilation. The addition of noise (random changes) to a monotonous nonlinear biological system, such as the lung, induces stochastic resonan...

A nonlinear generalisation of Principal Component Analysis (PCA) is applied to the 500mb geopotential height field of the Northern Hemisphere extratropical atmosphere. It is found that the low-frequency variability of the mid-troposphere is characterised by three distinct quasistationary states. The states are described and compared to those obtained from applications of cluster analyses and li...

Standard and dynamic current clamps were used to emulate dendritic GABA-Aergic postsynaptic currents (IPSCs) in a reconstructed thalamic relay neuron. The variability of somatically recorded single events was an order of magnitude smaller than reported in experimental work, suggesting that experimentally observed variability of miniature IPSCs re#ects variable synaptic strength rather than "lte...

This study investigated changes in the complexity (magnitude and structure of variability) of the collective behaviours of association football teams during competitive performance. Raw positional data from an entire competitive match between two professional teams were obtained with the ProZone tracking system. Five compound positional variables were used to investigate the collective patterns...

A fine networks of thermal data loggers has been set up in a viticultural site of the « Coteaux du Layon » to assess spatial variability of temperature within the vineyard. One part of the study aimed to point out wich local factors prevail in the temperature variability and to establish role and weight of each factors. That is why a multicriteria modeling based on multiple linear regressions h...

Because of low-frequency internal variability, the observed and underlying warming trends in temperature series can be markedly different. Important differences in the observed nonlinear trends in hemispheric temperature series suggest that the northern and southern hemispheres have responded differently to the changes in the radiative forcing. Using recent econometric techniques, we can reconc...

Global climate variability affects important local hydro-meteorological variables like precipitation and temperature. The Southern Oscillation (SO) is an easily quantifiable major driving force that gives impact on regional and local climate. The relationships between SO and local climate variation are, however, characterized by strongly nonlinear processes. Due to this, teleconnections between...

The characteristics of glacial oscillations changed drastically 0:8Ma ago, at the ‘‘mid-Pleistocene transition’’. During the past 0.8Ma the 100kyr glacial–interglacial oscillations were strongly asymmetric (i.e., long glacial intervals of growth followed by rapid intervals of deglaciation). The 40 kyr oscillations prior to the mid-Pleistocene transition were of a smaller amplitude and lessasymm...

The authors explore the use of the ‘‘neutral vectors’’ of a linearized version of a global quasigeostrophic atmospheric model with realistic mean flow in the study of the nonlinear model’s low-frequency variability. Neutral vectors are the (right) singular vectors of the linearized model’s tendency matrix that have the smallest eigenvalues; they are also the patterns that exhibit the largest re...