Our findings indicate that the impedance cardiogram spectrum extends from DC to 50 Hz. Any amplifier with an upper band limit less than 50 Hz can be expected to produce attenuation and distortion of the impedance cardiogram. This signal attenuation may be systematically enhanced under conditions of high heart rate when a greater proportion of signal energy will be in the upper frequency range o...

in this study, analysis is presented in two steps. in the first step, the theoretical s-wave displacement spectra, conditioned by frequency-independent q, was fitted with the observed displacement spectra. therefore corner frequency, moment magnitude and frequency-independent q for each record were estimated simultaneously and the estimate of error is given in the root-mean-square sense over al...

this paper proposes a low voltage (±0.55v supply voltage) low power (44.65µw) high common mode rejection ratio (cmrr) differential amplifier (d.a.) with rail to rail input common mode range (icmr), constant transconductance (gm) and enhanced frequency performance. its high performance is obtained using a simple negative averaging method so that it cancels out the common mode input signals at th...

We observed the response of vascular resistance and venous oxygen (O2) saturation to sinusoidally modulated continuous exercise of the isolated dog calf. Stimulus frequency was varied sinusoidally between 0.5 Hz and 1 Hz with modulation frequencies ranging from 0.005 Hz to 0.05 Hz. Venous O2 responses were corrected for dispersion due to vascular and catheter transit. As modulation frequency wa...

This paper proposes a low voltage (±0.55V supply voltage) low power (44.65µW) high common mode rejection ratio (CMRR) differential amplifier (d.a.) with rail to rail input common mode range (ICMR), constant transconductance (gm) and enhanced frequency performance. Its high performance is obtained using a simple negative averaging method so that it cancels out the common mode input signals at th...

Various drosophila mutants were used to dissect the electroretinogram (ERG) frequency response into components of different origins. The ommochrome granules in the receptor cell body are known to migrate in response to light, limiting the amount of light entering the rhabdomere. Comparison between the ERG frequency responses of the wild type and the mutant lacking the ommochrome granules indica...

The aim in the present experiments was to assess the dynamic baroreflex control of blood pressure, to develop an accurate mathematical model that represented this relationship, and to assess the role of dynamic changes in heart rate and stroke volume in giving rise to components of this response. Patterned electrical stimulation [pseudo-random binary sequence (PRBS)] was applied to the aortic d...

[1] Lg, a regional seismic wave comprised of multiple shear wave reverberations trapped in the crustal waveguide, is important for magnitude estimation and source discrimination for monitoring nuclear testing treaties. In stable continental regions, Lg propagates with a group velocity of about 3.5 km/s and can often be observed at distances up to 4000 km. To better understand the absence of hig...

Persistent low-frequency (<180 Hz) acoustic detection took place within the boundaries of Oak Ridge National Laboratory to monitor full power operations High Flux Isotope Reactor. Three sensors were installed at distances 69, 101, and 914 m from northeast corner cooling towers assess four reactor generation cycles. Features extracted spectral density calculations where data collected during ...

We examined the transfer function of autonomic heart rate (HR) control in anesthetized sedentary and exercise-trained (16 wk, treadmill for 1 h, 5 times/wk at 15 m/min and 15-degree grade) rats for comparison to HR variability assessed in the conscious resting state. The transfer function from sympathetic stimulation to HR response was similar between groups (gain, 4.2 ± 1.5 vs. 4.5 ± 1.5 beats...