Supramaximal stimuli, with time intervals of 100 ms (10 Hz) to 10 ms (100 Hz), were delivered in pairs to the phrenic nerves, bilaterally, in five seated normal subjects, while transdiaphragmatic pressure swings (Pdi,s) were recorded at relaxed end-expiratory lung volume with airways closed. In fresh diaphragms, Pdi,s increased between 10-20 Hz and reached a plateau between 20-30 Hz. Diaphragma...

manual citrus harvesting is commonly performing hard, expensive and time consuming. in this study, a factorial experiment with a completely randomized design in three replications was performed to find out the effect of frequency (three levels of 5, 7.5 and 10 hz), vibration time (three levels of 10, 15 and 20 seconds) on harvesting capacity and losses of thomson cultivar of orange. the results...

EEG recordings reflect the gross electrical activity emanating from synaptic currents of individual neurons across large cortical areas. During periods of cortical activation, waking, and higher EEG frequencies, neurons display increased excitability and exhibit more asynchronous discharge. The activity of a number of subcortical neurotransmitter systems from several brain regions outside the t...

Quantitative assessment of local field potentials by means of Fast Fourier Transformation (FFT) results in the so-called power density spectrum. Within this spectrum particular frequency ranges are defined in order to relate these to behavior. Frequencies above 35 Hz are generally labeled as gamma oscillations, especially as low gamma (40 55 Hz) or high gamma (70 100 Hz). In order to learn more...

We have used the wavelet transform to evaluate the time-frequency content of laser-Doppler flowmetry (LDF) signals measured simultaneously on the surfaces of free microvascular flaps deprived of sympathetic nerve activity (SNA), and on adjacent intact skin, in humans. It was thereby possible to determine the frequency interval within which SNA manifests itself in peripheral blood flow oscillati...

The objective of the presented studies is to attempt an evaluation of heart rate (HR) and heart rate variability (HRV) regulatory mechanisms in the presence of autonomous nervous system (ANS) components in transient exposure to high altitude hypoxia. During 24 hrs including a stay in hypobaria, the participants had their HR continuously recorded using the Holter method. The following parameters...

A two-interval forced-choice (2-IFC) tracking procedure was used to evaluate the effects of a 15-s pre-exposure to either 25 Hz or 200 Hz stimulation ("25 Hz or 200 Hz adaptation") on human vibrotactile frequency discrimination threshold (frequency DL/Weber fraction). Three subjects were studied. All stimuli (standard and comparison) were delivered to a central location on the thenar eminence o...

Spontaneous oscillatory electrical activity at a frequency near 40 Hz in the human brain and its reset by sensory stimulation have been proposed to be related to cognitive processing and to the temporal binding of sensory stimuli. These experiments were designed to test this hypothesis and to determine specifically whether the minimal interval required to identify separate auditory stimuli corr...

Power spectral analysis of heart rate (HR) variability is a useful tool with which to assess cardiac autonomic activity. The low frequency bands have been considered as both sympathetically and parasympathetically mediated components, while the high frequency bands have been assumed to be the parasympathetically mediated respiratory components. It has been anticipated that spinal anaesthesia to...