نتایج جستجو برای: الکترومغناطیسی vlf
تعداد نتایج: 3022 فیلتر نتایج به سال:
OBJECTIVES The dynamic interaction between blood pressure (BP) and cerebral blood flow velocity (CBFV) is not fully understood, especially for CBFV changes lasting longer than 50 s. The interaction between BP and CBFV is relatively well characterized for periods <50 s using transfer function (TF) estimations of phase, gain, and coherence. We used TF estimations to compare the phase and gain for...
OBJECTIVE Classic methods for assessing cerebral autoregulation involve a transfer function analysis performed using the Fourier transform to quantify relationship between fluctuations in arterial blood pressure (ABP) and cerebral blood flow velocity (CBFV). This approach usually assumes the signals and the system to be stationary. Such an presumption is restrictive and may lead to unreliable r...
The purpose of this study was to determine the funicular location of descending catecholamine (CA) fibers innervating the lumbar spinal cord from the dorsolateral pons (DLP). The locations of catecholamine-containing cell bodies which project to the lumbar spinal cord were determined by combining the use of the retrogradely transported fluorescent dye, Evans Blue (EB), with the glyoxylic acid h...
Hipot or voltage proof tests have long been used to assure the health of cable systems in the factory and when commissioning. A recent concern with this approach is that there is no way to judge if the effect of dropping VLF frequency (required to test long lengths) has a significant and deleterious impact on the effectiveness of a Simple Withstand Test. This paper shows how this problem has be...
Lightning discharge emits RF energy over a wide range of frequencies. During cloud to ground lightning, when high currents occur in previously ionized channels, the most powerful emissions occur in the Very Low Frequency range. VLF (very low frequency) refers to radio frequencies spectrum range of 3 kHz to 30 kHz. Detection of lightning makes it possible to avoid various harmful effects occurri...
[1] We thank Moore and Rietveld [2009] (hereafter referred to as MR09) for their comments to Cohen et al. [2008] (hereafter referred to as CA08). MR09 consider the two following conclusions of CA08 concerning the generation of ELF/VLF (0.3–30 kHz) waves with typical amplitude modulation (AM) and geometric modulation of ionospheric High-Frequency (HF) heating: 1) ‘‘Geometric modulation can enhan...
BACKGROUND Overactive bladder (OAB) is a clinical entity with complex, still incompletely understood pathophysiology, involving central and peripheral autonomic nervous system (ANS) disturbances. OBJECTIVES The aim of the study was to estimate ANS activity using spectral analysis of heart rate variability (HRV) in two experimental overactive bladder models: chemical, evoked by cyclophosphamid...
OBJECTIVE The present study compared heart rate variability (HRV) parameters in patients with coronary artery ectasia (CAE) and coronary artery disease (CAD). METHODS The study population consisted of 60 consecutive patients with CAE (14 women; mean age 51.63±7.44 years), 60 consecutive patients with CA (15 women; mean age 53.67±9.31 years), and 59 healthy individuals (13 women; mean age 52.8...
One of the most important effects ionospheric modification by high power, frequency (HF) waves is generation ultra low frequency/extremely frequency/very (ULF/ELF/VLF) modulated heating. This paper reviews scientific achievements past five decades regarding main mechanisms excitation ULF/ELF/VLF and discusses their characteristics, such as electrojet dependency, location source region, continuo...
[1] The magnitudes of scattered fields produced during early/fast very low frequency (VLF) events observed at 13 closely spaced ( 65 km) sites are compared with those expected for sprite halo disturbances using a numerical model of wave propagation within the Earth-ionosphere waveguide. Three different early/fast events of varying magnitudes are analyzed using three different nighttime ambient ...
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