Ogo 4 observations of extremely low frequency hiss.

NASA Technical Reports Server (NTRS)

Muzzio, J. L. R.; Angerami, J. J.

1972-01-01

Analysis of ELF and VLF data from the Stanford University experiment on Ogo 4 revealed an ELF hiss band with characteristics not previously identified. The band, referred to as band-limited ELF hiss, is seen from low to medium latitudes. On the basis of wave-propagation properties, it is proposed that the BLH is generated at large wave normal angles in the equatorial region near L = 4. This model can be used to explain the characteristics of the BLH. Two mechanisms for the generation of BLH based on radiation from energetic electrons are considered.

High-latitude distributions of plasma waves and spatial irregularities from DE 2 alternating current electric field observations

NASA Technical Reports Server (NTRS)

Heppner, J. P.; Liebrecht, M. C.; Maynard, N. C.; Pfaff, R. F.

1993-01-01

The high-latitude spatial distributions of average signal intensities in 12 frequency channels between 4 Hz and 512 kHz as measured by the ac electric field spectrometers on the DE-2 spacecraft are analyzed for 18 mo of measurements. In MLT-INL (magnetic local time-invariant latitude) there are three distinct distributions that can be identified with 4-512 Hz signals from spatial irregularities and Alfven waves, 256-Hz to 4.1-kHz signals from ELF hiss, and 4.1-64 kHz signals from VLF auroral hiss, respectively. Overlap between ELF hiss and spatial irregularity signals occurs in the 256-512 Hz band. VLF hiss signals extend downward in frequency into the 1.0-4.1 kHz band and upward into the frequency range 128-512 kHz. The distinctly different spatial distribution patterns for the three bands, 4-256 Hz, 512-1204 Hz, and 4.1-64 kHz, indicate a lack of any causal relationships between VLF hiss, ELF hiss, and lower-frequency signals from spatial irregularities and Alfven waves.

ELF/VLF Wave Generation and Scattering from Modulated Heating of the Ionosphere at Arecibo Observatory

NASA Astrophysics Data System (ADS)

Maxworth, A. S.; Golkowski, M.; McCormick, J.; Cohen, M.; Hosseini, P.; Bittle, J.

2017-12-01

The recently completed ionospheric heater at Arecibo Observatory is used for modulated HF (5 or 8 MHz) heating of the ionosphere, to generate ELF/VLF (3 Hz - 30 kHz) waves. Observation of ramp and tone signals at frequencies from hundreds of Hz to several kHz at multiple receivers confirms the ability of the heater to modulate D region currents and create an ELF/VLF antenna in the ionosphere. Observed ELF/VLF signal amplitudes are lower than for similar experiments performed at high latitudes at the HAARP and Tromso facilities, for a variety of reasons including the reduced natural currents at mid latitudes, and the lower HF power of the Arecibo heater. The heating of the overhead ionosphere is also observed to change the Earth-ionosphere waveguide propagation characteristics as is evident from simultaneous observations of lightning induced sferics and VLF transmitter signals that propagate under the heated region. The active heating of the ionosphere modifies the reflection of incident VLF (3-30 kHz) waves. We present initial observations of HF heating of the D-region and resulting ELF/VLF wave generation.

ELF wave production by an electron beam emitting rocket system and its suppression on auroral field lines - Evidence for Alfven and drift waves

NASA Astrophysics Data System (ADS)

Winckler, J. R.; Erickson, K. N.; Abe, Y.; Steffen, J. E.; Malcolm, P. R.

1985-07-01

Orthogonal probes on a free-flying plasma diagnostics payload are used to study ELF electric disturbances in the auroral ionosphere that are due to the injection of powerful electron beams. Frequency spectrograms are presented for various pitch angles, pulsing characteristics, and other properties of the injected beams; the large scale DC ionospheric convection electric field is measured, together with auroral particle precipitation, visual auroral forms, and ionospheric parameters. In view of the experimental results obtained, it is postulated that the observed ELF waves are in the Alfven and drift modes, and are generated by the positive vehicle potential during beam injection.

Polarization analysis of VLF/ELF waves observed at subauroral latitudes during the VLF-CHAIN campaign

NASA Astrophysics Data System (ADS)

Martinez-Calderon, Claudia; Shiokawa, Kazuo; Miyoshi, Yoshizumi; Ozaki, Mitsunori; Schofield, Ian; Connors, Martin

2015-02-01

Chorus wave emissions are one of the most intense naturally occurring phenomena in the very low (VLF) and extremely low frequency (ELF) ranges. They are believed to be one of the major contributors to acceleration and loss of electrons in the radiation belts. During the VLF Campaign observation with High-resolution Aurora Imaging Network (VLF-CHAIN) from 17 to 25 February 2012, several types of VLF/ELF emissions, including chorus, were observed at subauroral latitudes in Athabasca, Canada. To our knowledge, there has not been any comprehensive study of the physical properties of such emissions at these latitudes. In this study, we calculate spectral and polarization parameters of VLF/ELF waves with high temporal resolution. We found that the polarization angle of several emissions depended on both frequency and time. We suggest that the frequency-dependent events, which usually last several tens of minutes, might be the consequence of the broadening of the ray path that the waves follow from their generation region to the ground. Furthermore, time-dependent events, also lasting tens of minutes, have a polarization angle that changes from negative to positive values (or vice versa) every few minutes. We suggest that this could be due to variations of the wave duct, either near the generation region or along the wave propagation path. Using another ground station in Fort Vermillion, Canada, about 450 km northwest of Athabasca, we tracked the movements of the ionospheric exit point of three chorus emissions observed simultaneously at both stations. Although we found that movement of the ionospheric exit point does not follow a general direction, it is subject to hovering motion, suggesting that the exit point can be affected by small-scale plasma processes.

Correlation between core ion energization, suprathermal electron bursts, and broadband ELF plasma waves

NASA Astrophysics Data System (ADS)

Knudsen, David J.; Clemmons, James H.; Wahlund, Jan-Erik

1998-03-01

Observations of the lowest energy or core ions provide a particularly sensitive measure of the early stages of auroral ion energization. Freja satellite observations of 0-20 eV core ions in the topside auroral ionosphere and cusp/cleft show signs of heating within both regions of VLF hiss and broadband ELF plasma waves. However, heating to several eV or more is associated predominantly with the ELF waves. A correlation analysis of wave and core ion data formed from orbital segments shows that, on average, correlations are highest for wave frequencies below several hundred Hz, and less at VLF hiss frequencies. A similar analysis shows a higher correlation between electron precipitation and ion heating for electron energies below several hundred eV (i.e., the energies associated with suprathermal electron bursts) and a lower correlation above the 1 keV energies associated with auroral inverted-V's. Signs of core ion heating begin to appear when wave power at the O+ gyrofrequency exceeds about 10-3(mVm-1)2/Hz, and when the integrated field-aligned electron flux exceeds a few times 107cm-2s-1sr-1. This electron energy flux threshold is at least an order of magnitude lower than previously inferred from earlier studies comparing suprathermal electron fluxes and energetic ions. Almost all observed heating events occur during enhanced or active geomagnetic conditions; i.e., Kp>=4. While the most intense core ion heating is correlated with broadband ELF waves, we also present one example of weak ion heating of a few eV in a region of VLF auroral hiss.

DEMETER observations of manmade waves that propagate in the ionosphere

NASA Astrophysics Data System (ADS)

Parrot, Michel

2018-01-01

This paper is a review of manmade waves observed by the ionospheric satellite DEMETER. It concerns waves emitted by the ground-based VLF and ELF transmitters, by broadcasting stations, by the power line harmonic radiation, by industrial noise, and by active experiments. Examples are shown including, for the first time, the record of a wave coming from an ELF transmitter. These waves propagate upwards in the magnetosphere and they can be observed in the magnetically conjugated region of emission. Depending on their frequencies, they perturb the ionosphere and the particles in the radiation belts, and additional emissions are triggered. xml:lang="fr"

Artificial Aurora and Ionospheric Heating by HAARP

NASA Astrophysics Data System (ADS)

Hadavandkhani, S.; Nikouravan, Bijan; Ghazimaghrebi, F.

2016-08-01

A recent experiment was achieved at HAARP to study the scaling of the ionospherically generated ELF signal with power transmitted from the high frequency (HF) array. The results were in excellent agreement with computer simulations. The outcomes approving that the ELF power increases with the square of the incident HF power. This paper present a review on the situation of the ionized particles in Ionospheric layer when stimulated by artificial an ELF and VLF external high energy radio waves.

Collision Avoidance W-Band FMCW Radars in an Altimeter Application

DTIC Science & Technology

2006-08-01

underground mining applications. Potentially, a small low– powered downward looking aerial radar employing Frequency Modulated Continuous Wave (FMCW) ranging...frequency [1]. 3 Figure 3: Epsilon Lambda ELF 171-1A radar. Model and System block diagram [2]. 4 Figure 4: Beam limited resolution cell (after [3]). 6...Figure 5: (black curves) Projected SNR variation of clutter return with range for ELF 171-1A type system in different weather conditions. Clutter-to

Optimizing ELF/VLF generation via HF heating utilizing beam motion

NASA Astrophysics Data System (ADS)

Cohen, M. B.; Inan, U. S.; Lehtinen, N. G.; Golkowski, M. A.

2008-12-01

ELF/VLF (300 Hz - 30 kHz) waves are difficult to generate with conventional antennae due to their extraordinary long wavelengths, and the good conductance of the Earth at these frequencies. Recently, ELF and VLF waves have been generated using HF (3-10 MHz) heating of the lower ionosphere, in the presence of natural currents such as the auroral electrojet, which modulates the ionospheric conductivity and therefore turns the lower ionosphere into a large radiating element. The recently upgraded HAARP facility, near Gakona Alaska, utilizes 3.6 MW of HF power, along with an unprecedented ability to steer the HF heating beam over a large area extremely rapidly. Since the completion of the upgrade in 2007, the first successful implementation of techniques such as geometric modulation [Cohen et al. 2008, Borisov et al. 1998], and beam painting [Papadopoulos et al. 1989] have occurred. These results have shown as much as 7-11 dB improvement in the signal strengths, as well as the first ability to direct ELF/VLF signals via an unprecedented ELF/VLF phased array. Here, we use a combination of experimental and theoretical investigations to discuss the optimization of ELF/VLF generation via HF heating, including the effect of HF and ELF frequency on the amplitude and the directional pattern for various generation techniques. The experimental observations occur over an array of receivers across Alaska. The theoretical formulation utilizes a 3D model of the HF heating and subsequent electron cooling processes, leading to spatial structure of modulated ionospheric conductivities, the results of which are input into a model of ELF/VLF propagation in the Earth-ionosphere waveguide.

System engineering study of electrodynamic tether as a spaceborne generator and radiator of electromagnetic waves in the ULF/ELF frequency band

NASA Technical Reports Server (NTRS)

Estes, R. D.; Grossi, M. D.; Lorenzini, E. C.

1986-01-01

The transmission and generation by orbiting tethered satellite systems of information carrying electromagnetic waves in the ULF/ELF frequency band to the Earth at suitably high signal intensities was examined and the system maintaining these intensities in their orbits for long periods of time without excessive onboard power requirements was investigated. The injection quantity power into electromagnetic waves as a function of system parameters such as tether length and orbital height was estimated. The basic equations needed to evaluate alternataing current tethered systems for external energy requirements are presented. The energy equations to tethered systems with various lengths, tether resistances, and radiation resistances, operating at different current values are applied. Radiation resistance as a function of tether length and orbital height is discussed. It is found that ULF/ELF continuously radiating systems could be maintained in orbit with moderate power requirements. The effect of tether length on the power going into electromagnetic waves and whether a single or dual tether system is preferable for the self-driven mode is discussed. It is concluded that the single tether system is preferable over the dual system.

Power-Stepped HF Cross Modulation Experiments at HAARP

NASA Astrophysics Data System (ADS)

Greene, S.; Moore, R. C.; Langston, J. S.

2013-12-01

High frequency (HF) cross modulation experiments are a well established means for probing the HF-modified characteristics of the D-region ionosphere. In this paper, we apply experimental observations of HF cross-modulation to the related problem of ELF/VLF wave generation. HF cross-modulation measurements are used to evaluate the efficiency of ionospheric conductivity modulation during power-stepped modulated HF heating experiments. The results are compared to previously published dependencies of ELF/VLF wave amplitude on HF peak power. The experiments were performed during the March 2013 campaign at the High Frequency Active Auroral Research Program (HAARP) Observatory. HAARP was operated in a dual-beam transmission format: the first beam heated the ionosphere using sinusoidal amplitude modulation while the second beam broadcast a series of low-power probe pulses. The peak power of the modulating beam was incremented in 1-dB steps. We compare the minimum and maximum cross-modulation effect and the amplitude of the resulting cross-modulation waveform to the expected power-law dependence of ELF/VLF wave amplitude on HF power.

Effects of electromagnetic radiation exposure on stress-related behaviors and stress hormones in male wistar rats.

PubMed

Mahdavi, Seyed Mohammad; Sahraei, Hedayat; Yaghmaei, Parichehreh; Tavakoli, Hassan

2014-11-01

Studies have demonstrated that electromagnetic waves, as the one of the most important physical factors, may alter cognitive and non-cognitive behaviors, depending on the frequency and energy. Moreover, non-ionizing radiation of low energy waves e.g. very low frequency waves could alter this phenomenon via alterations in neurotransmitters and neurohormones. In this study, short, medium, and long-term exposure to the extremely low frequency electromagnetic field (ELF-EMF) (1 and 5 Hz radiation) on behavioral, hormonal, and metabolic changes in male Wistar rats (250 g) were studied. In addition, changes in plasma concentrations for two main stress hormones, noradrenaline and adrenocorticotropic hormone (ACTH) were evaluated. ELF-EMF exposure did not alter body weight, and food and water intake. Plasma glucose level was increased and decreased in the groups which exposed to the 5 and 1Hz wave, respectively. Plasma ACTH concentration increased in both using frequencies, whereas nor-adrenaline concentration showed overall reduction. At last, numbers of rearing, sniffing, locomotor activity was increased in group receiving 5 Hz wave over the time. In conclusions, these data showed that the effects of 1 and 5 Hz on the hormonal, metabolic and stress-like behaviors may be different. Moreover, the influence of waves on stress system is depending on time of exposure.

Effects of Electromagnetic Radiation Exposure on Stress-Related Behaviors and Stress Hormones in Male Wistar Rats

PubMed Central

Mahdavi, Seyed Mohammad; Sahraei, Hedayat; Yaghmaei, Parichehreh; Tavakoli, Hassan

2014-01-01

Studies have demonstrated that electromagnetic waves, as the one of the most important physical factors, may alter cognitive and non-cognitive behaviors, depending on the frequency and energy. Moreover, non-ionizing radiation of low energy waves e.g. very low frequency waves could alter this phenomenon via alterations in neurotransmitters and neurohormones. In this study, short, medium, and long-term exposure to the extremely low frequency electromagnetic field (ELF-EMF) (1 and 5 Hz radiation) on behavioral, hormonal, and metabolic changes in male Wistar rats (250 g) were studied. In addition, changes in plasma concentrations for two main stress hormones, noradrenaline and adrenocorticotropic hormone (ACTH) were evaluated. ELF-EMF exposure did not alter body weight, and food and water intake. Plasma glucose level was increased and decreased in the groups which exposed to the 5 and 1Hz wave, respectively. Plasma ACTH concentration increased in both using frequencies, whereas nor-adrenaline concentration showed overall reduction. At last, numbers of rearing, sniffing, locomotor activity was increased in group receiving 5 Hz wave over the time. In conclusions, these data showed that the effects of 1 and 5 Hz on the hormonal, metabolic and stress-like behaviors may be different. Moreover, the influence of waves on stress system is depending on time of exposure. PMID:25489427

The detection of gravitational waves using electrodynamic system of Earth

NASA Astrophysics Data System (ADS)

Grunskaya, Lubov; Isakevich, Valiriy

There is studied the interconnection of tide processes of geophysical and astrophysical origin with the Earth electromagnetic fields. There has been developed a programme-analytical system (PAS) to investigate signal structures in spectral and time series, caused by geophysical and astrophysical processes based on the method of eigen vectors. There were discovered frequencies in the electrical and geomagnetical field of ELF range with PAS, which coincide with the frequency of gravitational -wave radiation of a number of double stellar systems. In the electrical and geomagnetic field there was discovered a specific axion frequency VA=0.5*10-5 Hz belonging to the ELF range which was predicted by the theory. The problem of the anomalous behavior of the electrodynamic system response to the gravitational - wave affect is being discussed. On the basis of the rich experimental material have been investigated the frequencies of gravitational-wave radiation of a number of binary systems: J0700+6418, J1012+5307, J1537+1155, J1959+2048, J2130+1210, J1915+1606. The work is carried out with supporting of RFFI No. 14-07-97510, State Task to Universities on 2014-2016.

Electromagnetic Waves and Bursty Electron Acceleration: Implications from Freja

NASA Technical Reports Server (NTRS)

Andersson, Laila; Ivchenko, N.; Wahlund, J.-E.; Clemmons, J.; Gustavsson, B.; Eliasson, L.

2000-01-01

Dispersive Alfven wave activity is identified in four dayside auroral oval events measured by the Freja satellite. The events are characterized by ion injection, bursty electron precipitation below about I keV, transverse ion heating and broadband extremely low frequency (ELF) emissions below the lower hybrid cutoff frequency (a few kHz). The broadband emissions are observed to become more electrostatic towards higher frequencies. Large-scale density depletions/cavities, as determined by the Langmuir probe measurements, and strong electrostatic emissions are often observed simultaneously. A correlation study has been carried out between the E- and B-field fluctuations below 64 Hz (the dc instrument's upper threshold) and the characteristics of the precipitating electrons. This study revealed that the energization of electrons is indeed related to the broadband ELF emissions and that the electrostatic component plays a predominant role during very active magnetospheric conditions. Furthermore, the effect of the ELF electromagnetic emissions on the larger scale field-aligned current systems has been investigated, and it is found that such an effect cannot be detected. Instead, the Alfvenic activity creates a local region of field-aligned currents. It is suggested that dispersive Alfven waves set up these local field-aligned current regions and in turn trigger more electrostatic emissions during certain conditions. In these regions ions are transversely heated, and large-scale density depletions/cavities may be created during especially active periods.

System engineering study of electrodynamic tether as a spaceborne generator and radiator of electromagnetic waves in the ULF/ELF frequency band

NASA Technical Reports Server (NTRS)

Estes, Robert D.

1987-01-01

An electrodynamic tether deployed from a satellite in low-Earth orbit can perform, if properly instrumented, as a partially self-powered generator of electromagnetic waves in the ULF/ELF band, potentially at power levels high enough to be of practical use. Two basic problems are examined. The first is that of the level of wave power that the system can be expected to generate in the ULF/ELF radiation band. The second major question is whether an electrodynamic tethered satellite system for transmitting waves can be made partially self-powering so that power requirements for drag compensation can be met within economical constraints of mass, cost, and complexity. The theoretical developments and the system applications study are presented. The basic design criteria, the drag-compensation method, the effects on the propagation paths from orbit to Earth surface of high-altitude nuclear debris patches, and the estimate of masses and sizes are covered. An outline of recommended analytical work, to be performed as a follow-on to the present study, is contained.

ELF/VLF Perturbations Above the Haarp Transmitter Recorded by the Demeter Satellite in the Upper Ionosphere

NASA Astrophysics Data System (ADS)

Titova, E. E.; Demekhov, A. G.; Mochalov, A. A.; Gvozdevsky, B. B.; Mogilevsky, M. M.; Parrot, M.

2015-08-01

In the studies of the data received from DEMETER (orbit altitude above the Earth is about 700 km), we detected for the first time electromagnetic perturbations, which are due to the ionospheric modification by HAARP, a high-power high-frequency transmitter, simultaneously in the extremely low-frequency (ELF, below 1200 Hz) and very low-frequency (VLF, below 20 kHz) ranges. Of the thirteen analyzed flybys of the satellite above the heated area, the ELF/VLF signals were detected in three cases in the daytime (LT = 11-12 h), when the minimum distance between the geomagnetic projections of the satellite and the heated area center on the Earth's surface did not exceed 31 km. During the nighttime flybys, the ELF/VLF perturbations were not detected. The size of the perturbed region was about 100 km. The amplitude, spectrum, and polarization of the ELF perturbations were analyzed, and their comparison with the characteristics of natural ELF noise above the HAARP transmitter was performed. In particular, it was shown that in the daytime the ELF perturbation amplitude above the heated area can exceed by a factor of 3 to 8 the amplitude of natural ELF noise. The absence of the nighttime records of artificial ELF/VLF perturbations above the heated area can be due to both the lower frequency of the heating signal, at which the heating occurs in the lower ionosphere, and the higher level of natural noise. The spectrum of the VLF signals related to the HAARP transmitter operation had two peaks at frequencies of 8 to 10 kHz and 15 to 18 kHz, which are close to the first and second harmonics of the lower-hybrid resonance in the heated area. The effect of the whistler wave propagation near the lower-hybrid resonance region on the perturbation spectrum recorded in the upper ionosphere for these signals has been demonstrated. In particular, some of the spectrum features can be explained by assuming that the VLF signals propagate in quasiresonance, rather than quasilongitudinal, regime. It is noted that the profile and dynamics of the ELF perturbation frequency spectrum conform to the assumption of their connection with quasistatic small-scale electron-density inhomogeneities occurring in the heated region and having lifetimes of a few seconds or more. The possible mechanisms of the ELF/VLF perturbation formation in the ionospheric plasma above the high-latitude HAARP facility at the DEMETER flyby altitudes are discussed.

First demonstration of HF-driven ionospheric currents

NASA Astrophysics Data System (ADS)

Papadopoulos, K.; Chang, C.-L.; Labenski, J.; Wallace, T.

2011-10-01

The first experimental demonstration of HF driven currents in the ionosphere at low ELF/ULF frequencies without relying in the presence of electrojets is presented. The effect was predicted by theoretical/computational means in a recent letter and given the name Ionospheric Current Drive (ICD). The effect relies on modulated F-region HF heating to generate Magneto-Sonic (MS) waves that drive Hall currents when they reach the E-region. The Hall currents inject ELF waves into the Earth-Ionosphere waveguide and helicon and Shear Alfven (SA) waves in the magnetosphere. The proof-of-concept experiments were conducted using the HAARP heater in Alaska under the BRIOCHE program. Waves between 0.1-70 Hz were measured at both near and far sites. The letter discusses the differences between ICD generated waves and those relying on modulation of electrojets.

Diurnal variations of ELF transients and background noise in the Schumann resonance band

NASA Astrophysics Data System (ADS)

Greenberg, Eran; Price, Colin

2007-02-01

Schumann resonances (SR) are resonant electromagnetic waves in the Earth-ionosphere cavity, induced primarily by lightning discharges, with a fundamental frequency of about 8 Hz and higher-order modes separated by approximately 6 Hz. The SR are made up of the background signal resulting from global lightning activity and extremely low frequency (ELF) transients resulting from particularly intense lightning discharges somewhere on the planet. Since transients within the Earth-ionosphere cavity due to lightning propagate globally in the ELF range, we can monitor and study global ELF transients from a single station. Data from our Negev Desert (Israel) ELF site are collected using two horizontal magnetic induction coils and a vertical electric field ball antenna, monitored in the 5-40 Hz range with a sampling frequency of 250 Hz. In this paper we present statistics related to the probability distribution of ELF transients and background noise in the time domain and its temporal variations during the day. Our results show that the ELF signal in the time domain follows the normal distribution very well. The σ parameter exhibits three peaks at 0800, 1400, and 2000 UT, which are related to the three main global lightning activity centers in Asia, Africa, and America, respectively. Furthermore, the occurrence of intense ELF events obeys the Poisson distribution, with such intense events occurring every ~10 s, depending on the time of the day. We found that the diurnal changes of the σ parameter are several percent of the mean, while for the number of intense events per minute, the diurnal changes are tens of percent about the mean. We also present the diurnal changes of the SR intensities in the frequency domain as observed at our station. To better understand the diurnal variability of the observations, we simulated the measured ELF background noise using space observations as input, as detected by the Optical Transient Detector (OTD). The most active center which is reflected from both ELF measurements and OTD observations is in Africa. However, the second most active center on the basis of ELF measurements appears to be Asia, while OTD observations show that the American center is more active than the Asian center. These differences are discussed. This paper contributes to our understanding of the origin of the SR by comparing different lightning data sets: background electromagnetic radiation and optical emission observed from space.

Midlatitude detection of ELF whistlers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sentman, D.D.; Ehring, D.A.

1994-02-01

Narrow-band, whistlerlike magnetic events distinguished by nearly monochromatic signals decreasing in frequency with time have been observed for the first time at midlatitudes in the ELF band. Measurements performed during September 3 to October 5, 1985 at Table Mountain, California (34.4{degrees}N, 117.7{degrees}W), show that the frequency and dispersion characteristics of these events are similar to events detected at auroral latitudes, including a narrow-band magnetic signal monotonically decreasing in frequency from 120 to 60 Hz over a 40 s interval with a mean center frequency of approximately 90 Hz. No echoes were observed. Maximum amplitudes of the magnetic signals ranged frommore » just above the approximately 1 pT Hz{sup {minus}1/2} floor of the ambient background to roughly 20 pT Hz{sup {minus}1/2}. The polarization was predominantly linear in the geographic east-west direction. The midlatitude ELF whistlers reported here have a significantly lower average daily rate of occurrence than those reported for auroral latitudes. However, as with the high-latitude events, they displayed an occurrence rate that is maximum during local daytime. Following Heacock, it is suggested that a possible source for these events is whistler mode lion roars occurring in field-aligned ducts of enhanced cold plasma densities in the magnetosheath into the polar cusp, the waves may propagate to the Earth through the cusp acting as a waveguide. Although lightning is usually considered to be the dominant source of ELF noise in the Earth ionosphere cavity, magnetosheath ELF noise coupled into the cavity at high latitudes may represent an additional source. The fractional intensities of the natural ELF noise power within the cavity that are generated by this mechanism are presently unknown. 28 refs., 5 figs., 1 tab.« less

Multiple-Station Observation of Frequency Dependence and Polarization Characteristics of ELF/VLF waves generated via Ionospheric Modification

NASA Astrophysics Data System (ADS)

Maxworth, A. S.; Golkowski, M.; Cohen, M.; Moore, R. C.

2014-12-01

Generation of Extremely Low Frequency (ELF) and Very Low Frequency (VLF) signals through ionospheric modification has been practiced for many years. Heating the lower ionosphere with high power HF waves allows for modulation of natural current systems. Our experiments were carried out at the High Frequency Active Auroral Research Program (HAARP) facility in Alaska, USA. In this experiment, the ionosphere was heated with a vertical amplitude modulating signal and the modulation frequency was changed sequentially within an array of 40 frequencies followed by a frequency ramp. The observed magnetic field amplitude and polarization of the generated ELF/VLF signals were analyzed for multiple sites and as a function of modulation frequency. Our three observation sites: Chistochina, Paxson and Paradise are located within 36km (azimuth 47.7°), 50.2km (azimuth -20°) and 99km (azimuth 80.3°) respectively. We show that the peak amplitudes observed as a function of frequency result from vertical resonance in the Earth-ionosphere waveguide and can be used to diagnose the D-region profile. Polarization analysis showed that out of the three sites Paxson shows the highest circularity in the magnetic field polarization, compared to Chistochina and Paradise which show highly linear polarizations. The experimental results were compared with a theoretical simulation model results and it was clear that in both cases, the modulated Hall current dominates the observed signals at Chistochina and Paradise sites and at Paxson there is an equal contribution from Hall and Pedersen currents. The Chistochina site shows the highest magnetic field amplitudes in both experimental and simulation environments. Depending upon the experimental and simulation observations at the three sites, a radiation pattern for the HAARP ionospheric heater can be mapped

On the observations of unique low latitude whistler-triggered VLF/ELF emissions

NASA Astrophysics Data System (ADS)

Altaf, M.; Singh, K. K.; Singh, A. K.; Lalmani

A detailed analysis of the VLF/ELF wave data obtained during a whistler campaign under All India Coordinated Program of Ionosphere Thermosphere Studies (AICPITS) at our low latitude Indian ground station Jammu (geomag. lat. = 22° 26‧ N, L = 1.17) has yielded two types of unusual and unique whistler-triggered VLF/ELF emissions. These include (1) whistler-triggered hook emissions and (2) whistler-triggered long enduring discrete chorus riser emissions in VLF/ELF frequency range during night time. Such types of whistler-triggered emissions have not been reported earlier from any of the ground observations at low latitudes. In the present study, the observed characteristics of these emissions are described and interpreted. Dispersion analysis of these emissions show that the whistlers as well as emissions have propagated along a higher geomagnetic field line path with L-values lying ∼L = 4, suggesting that these triggered emissions are to be regarded as mid-latitude emissions. These waves could have propagated along the geomagnetic field lines either in a ducted mode or in a pro-longitudinal (PL) mode. The measured intensity of the triggered emissions is almost equal to that of the source waves and does not vary throughout the period of observation on that day. It is speculated that these emissions may have been generated through a process of resonant interaction of the whistler waves with energetic electrons. Parameters related to this interaction are computed for different values of L and wave amplitude. The proposed mechanism explains some aspects of the dynamic spectra.

Vadim C. Mushtak (1947-2013)

NASA Astrophysics Data System (ADS)

Williams, E.; Mushtak, N.; Temidis, E.; Galyuk, Y. P.; Nickolaenko, A. P.

2014-05-01

Vadim Constantinovich Mushtak, renowned for his work in radio physics and atmospheric electricity, died on 25 September 2013 in an automobile accident in Walker Valley, N.Y. He was 65. Vadim was a world expert in extremely low frequency (ELF) wave propagation and the Earth's naturally occurring Schumann resonances (SR)—quasi-standing electromagnetic waves trapped in the Earth-ionosphere cavity.

A survey of ELF and VLF research on lightning-ionosphere interactions and causative discharges

NASA Astrophysics Data System (ADS)

Inan, U. S.; Cummer, S. A.; Marshall, R. A.

2010-06-01

Extremely low frequency (ELF) and very low frequency (VLF) observations have formed the cornerstone of measurement and interpretation of effects of lightning discharges on the overlying upper atmospheric regions, as well as near-Earth space. ELF (0.3-3 kHz) and VLF (3-30 kHz) wave energy released by lightning discharges is often the agent of modification of the lower ionospheric medium that results in the conductivity changes and the excitation of optical emissions that constitute transient luminous events (TLEs). In addition, the resultant ionospheric changes are best (and often uniquely) observable as perturbations of subionospherically propagating VLF signals. In fact, some of the earliest evidence for direct disturbances of the lower ionosphere in association with lightning discharges was obtained in the course of the study of such VLF perturbations. Measurements of the detailed ELF and VLF waveforms of parent lightning discharges that produce TLEs and terrestrial gamma ray flashes (TGFs) have also been very fruitful, often revealing properties of such discharges that maximize ionospheric effects, such as generation of intense electromagnetic pulses (EMPs) or removal of large quantities of charge. In this paper, we provide a review of the development of ELF and VLF measurements, both from a historical point of view and from the point of view of their relationship to optical and other observations of ionospheric effects of lightning discharges.

Study on characteristic frequencies of ELF emissions and estimation of ion constituents in the vicinity of magnetic equator

NASA Astrophysics Data System (ADS)

Matsuda, S.; Kasahara, Y.; Goto, Y.

2012-12-01

The AKEBONO satellite has been operated continuously over 2 cycles of solar activity. Long-term observation data obtained by the AKEBONO satellite is very valuable to clarify plasma dynamics in the magnetosphere. Recently, the mechanism of wave-particle interaction around the radiation belt has attracted considerable attention. The ELF receiver, which is a sub-system of the VLF instruments onboard AKEBONO, measures waveforms below 50Hz for one component of electric field and three components of magnetic field, or waveforms below 100Hz for one component of electric and magnetic field, respectively. It was reported that ion cyclotron waves were observed near magnetic equator by the receiver [1] . It is well known that ion cyclotron wave generally propagates with a left-handed circularly polarization, but there exists right-handed polarized ion cyclotron wave below a characteristic frequency called 'crossover' in the presence of two or more kinds of ions such as oxygen and helium ions besides proton. As the crossover frequency can be derived theoretically from relative constituents of ions in plasma, it is possible to estimate the ion constituents by identifying the crossover frequency observationally. In this study, we analyze polarization of the ion cyclotron waves observed around the magnetic equator by the ELF receiver onboard AKEBONO, and report an example of ion cyclotron wave whose polarization changes from left-handed to right-handed at crossover frequency. As a next step, we estimate the ion constituents according to the polarization analysis. Furthermore, these phenomena sometimes have characteristic lower cut-off frequencies changing along the trajectories of Akebono. According to our work, it was found that the cutoff frequency is frequently in agreement with 1/n of proton's cyclotron frequency, where "n" is integer. The lower cut-off of ion cyclotron wave can be theoretically derived considering certain ion constituents of the background cold plasma. However, it remains several different interpretations depending on the species of ions and their ion constituents. In this study, we set up the following two hypotheses which shall satisfy dozens of such phenomena observed in 1989 and 1990: 1) Constituents of major ions in the plasmasphere (i.e., H^{+}, He^{+}) happened to coincide the condition that gives observed lower cut-off frequency along the trajectory. 2) There exists minor ions (i.e., D^{+}, T^{+}) that have cyclotron frequencies at 1/n of proton's cyclotron frequency. We examine the validity of the above hypotheses referring electron density and Dst index of the corresponding period. The present study could be a promising technique to estimate ion constituents from plasma wave observation by Akebono in the radiation belt. It is also noted that it can be also applicable to the ERG mission, which is expected to provide important clues for solving plasma dynamics in the Earth's radiation belt by means of integrated observation of electric and magnetic fields, particles and waves. [1] Y. Kasahara, A. Sawada, M. Yamamoto, I. Kimura, S. Kokubun, and K. Hayashi, Ion Cyclotron Emissions Observed by the Satellite Akebono in the vicinity of the Magnetic Equator, Radio Science, 27, 347-362, 1992.

Indian Nuclear Command and Control Dilemma

DTIC Science & Technology

2006-09-01

Submarine Communications .............................................................53 a. ELF Communications ...system is activated and deployed. The crews of submarines are informed through this system and other long wave ( ELF and VLF) radio communication ...through connectivity links of ELF , VLF and TACAMO airborne VLF communication systems. a. ELF Communications The U.S. Navy’s ELF Communication

Extremely low-frequency electromagnetic field exposure enhances inflammatory response and inhibits effect of antioxidant in RAW 264.7 cells.

PubMed

Kim, Soo Jeong; Jang, Ye Won; Hyung, Kyung Eun; Lee, Da Kyoung; Hyun, Kee Hyeob; Jeong, Seung Hwarn; Min, Kyung Hoon; Kang, Wonku; Jeong, Ji Hoon; Park, So-Young; Hwang, Kwang Woo

2017-07-01

In recent years, there has been a dramatic increase in the number and variety of electronic devices that emit electromagnetic waves. Because people live and work in close proximity to these pieces of electrical equipment, there is growing concern surrounding the destruction of homeostasis by electromagnetic field exposure. In the present study, the effects of 60 Hz 0.8 mT extremely low-frequency electromagnetic fields (ELF-EMF) on a macrophage cell line (RAW 264.7) were examined. Under defined ELF-EMF exposure conditions, the production of nitric oxide and pro-inflammatory cytokines, TNF-α, IL-1β, and IL-6, were increased in RAW 264.7 cells and the expression of those genes was also upregulated. However, cell proliferation was not altered. Translocation of NF-κB (nuclear factor kappa B), molecules that act downstream of the pro-inflammatory cytokines, were increased to the nucleus under ELF-EMF exposure conditions. In addition, we found that ELF-EMF exposure elevated activation of nuclear factor of activated T cells (NFAT) 2, as well as positively affected the influx of calcium. Furthermore, with both the presence of a potent antioxidant (Resveratrol) and downregulation of the antioxidant-related gene Prx-1 (Peroxiredoxin-1), ELF-EMF was associated with higher inflammatory responses of macrophages. These results suggest that an ELF-EMF amplifies inflammatory responses through enhanced macrophage activation and can decrease the effectiveness of antioxidants. Bioelectromagnetics. 38:374-385, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Unusual whistler with very large dispersion near the magnetopause: Geotail observation and ray-tracing modeling

NASA Astrophysics Data System (ADS)

Nagano, I.; Wu, X.-Y.; Yagitani, S.; Miyamura, K.; Matsumoto, H.

1998-06-01

A case of highly dispersed (~860 s1/2) whistler-like ELF (700-960 Hz) wave was detected with the waveform capture (WFC) receiver aboard the Geotail satellite during a dayside magnetopause skimming. Features of the single event distinguish it from the usual falling tone discrete emissions. By ray-tracing and full-wave calculation, the accessibility of the waves from a ground source of a distorted model magnetosphere were investigated. We propose that a lightning discharge at high latitudes is the most plausible source of the event via a special propagation effect revealed by the ray tracing. We demonstrate that the observed large wavenormal angle with respect to the geomagnetic field, the unusually large level of dispersion, and the lack of the expected nose frequency might be attributable to the frequency-dependent nonducted paths to the satellite. The rare occurrence may partly be caused by the Landau damping by the convecting suprathermal electron beams of several hundred eV. It is also shown that the multiple-hop magnetospherically reflected (MR) whistlers from middle latitudes, though being refracted to higher L shells by the plasmapause, are unable to reach the outer magnetosphere. Interhemisphere ducted propagation is possible for ELF waves along a narrow, modestly (15% or more) enhanced flux tube and shows an upper cutoff frequency governed by the high-latitude minimum-magnetic field ``horns'' regions and the duct enhancement and diameter. A full-wave calculation also implies no lower-frequency cutoff in the upward ionospheric transmission of lightning radiation down to 200 Hz. Because of the complexity of the various effects that influence the propagation from a ground source and the very low occurrence, effective whistler mode waves diagnostics of the highly variable outer magnetosphere are at present beyond our reach.

Handling Nonlinearities in ELF/VLF Generation Using Modulated Heating at HAARP

NASA Astrophysics Data System (ADS)

Jin, G.; Spasojevic, M.; Cohen, M.; Inan, U. S.

2011-12-01

George Jin Maria Spasojevic Morris Cohen Umran Inan Stanford University Modulated HF heating of the D-region ionosphere near the auroral electrojet can generate extremely low frequency (ELF) waves in the kilohertz range. This process is nonlinear and generates harmonics at integer multiples of the ELF modulation frequency. The nonlinear distortion has implications for any communications applications since the harmonics contain a substantial fraction of the signal power and use up bandwidth. We examine two techniques for handling the nonlinearity. First we modulate the HF heating with a non-sinusoidal envelope designed to create a sinusoidal change in the Hall conductivity at a particular altitude in the ionosphere to minimize any generated harmonics. The modulation waveform is generated by inverting a numerical HF heating model, starting from the desired conductivity time series, and obtaining the HF power envelope that will result in that conductivity. The second technique attempts to use the energy in the harmonics to improve bit error rates when digital modulation is applied to the ELF carrier. In conventional quadrature phase-shift keying (QPSK), where a ELF carrier is phase-shifted by 0°, 90°, 180°, and 270° in order to transmit a pair of bits, the even harmonics cannot distinguish between the four possible shifts. By using different phase values, all the energy in the harmonics can contribute to determining the phase of the carrier and thus improve the bit error rate.

The Plasma Wave Experiment (PWE) on board the Arase (ERG) satellite

NASA Astrophysics Data System (ADS)

Kasahara, Yoshiya; Kasaba, Yasumasa; Kojima, Hirotsugu; Yagitani, Satoshi; Ishisaka, Keigo; Kumamoto, Atsushi; Tsuchiya, Fuminori; Ozaki, Mitsunori; Matsuda, Shoya; Imachi, Tomohiko; Miyoshi, Yoshizumi; Hikishima, Mitsuru; Katoh, Yuto; Ota, Mamoru; Shoji, Masafumi; Matsuoka, Ayako; Shinohara, Iku

2018-05-01

The Exploration of energization and Radiation in Geospace (ERG) project aims to study acceleration and loss mechanisms of relativistic electrons around the Earth. The Arase (ERG) satellite was launched on December 20, 2016, to explore in the heart of the Earth's radiation belt. In the present paper, we introduce the specifications of the Plasma Wave Experiment (PWE) on board the Arase satellite. In the inner magnetosphere, plasma waves, such as the whistler-mode chorus, electromagnetic ion cyclotron wave, and magnetosonic wave, are expected to interact with particles over a wide energy range and contribute to high-energy particle loss and/or acceleration processes. Thermal plasma density is another key parameter because it controls the dispersion relation of plasma waves, which affects wave-particle interaction conditions and wave propagation characteristics. The DC electric field also plays an important role in controlling the global dynamics of the inner magnetosphere. The PWE, which consists of an orthogonal electric field sensor (WPT; wire probe antenna), a triaxial magnetic sensor (MSC; magnetic search coil), and receivers named electric field detector (EFD), waveform capture and onboard frequency analyzer (WFC/OFA), and high-frequency analyzer (HFA), was developed to measure the DC electric field and plasma waves in the inner magnetosphere. Using these sensors and receivers, the PWE covers a wide frequency range from DC to 10 MHz for electric fields and from a few Hz to 100 kHz for magnetic fields. We produce continuous ELF/VLF/HF range wave spectra and ELF range waveforms for 24 h each day. We also produce spectral matrices as continuous data for wave direction finding. In addition, we intermittently produce two types of waveform burst data, "chorus burst" and "EMIC burst." We also input raw waveform data into the software-type wave-particle interaction analyzer (S-WPIA), which derives direct correlation between waves and particles. Finally, we introduce our PWE observation strategy and provide some initial results.[Figure not available: see fulltext.

Application of a simplified theory of ELF propagation to a simplified worldwide model of the ionosphere

NASA Astrophysics Data System (ADS)

Behroozi-Toosi, A. B.; Booker, H. G.

1980-12-01

The simplified theory of ELF wave propagation in the earth-ionosphere transmission lines developed by Booker (1980) is applied to a simplified worldwide model of the ionosphere. The theory, which involves the comparison of the local vertical refractive index gradient with the local wavelength in order to classify the altitude into regions of low and high gradient, is used for a model of electron and negative ion profiles in the D and E regions below 150 km. Attention is given to the frequency dependence of ELF propagation at a middle latitude under daytime conditions, the daytime latitude dependence of ELF propagation at the equinox, the effects of sunspot, seasonal and diurnal variations on propagation, nighttime propagation neglecting and including propagation above 100 km, and the effect on daytime ELF propagation of a sudden ionospheric disturbance. The numerical values obtained by the method for the propagation velocity and attenuation rate are shown to be in general agreement with the analytic Naval Ocean Systems Center computer program. It is concluded that the method employed gives more physical insights into propagation processes than any other method, while requiring less effort and providing maximal accuracy.

Using Schumann Resonance Measurements for Constraining the Water Abundance on the Giant Planets - Implications for the Solar System Formation

NASA Technical Reports Server (NTRS)

Simoes, Fernando; Pfaff, Robert; Hamelin, Michel; Klenzing, Jeffrey; Freudenreich, Henry; Beghin, Christian; Berthelier, Jean-Jacques; Bromund, Kenneth; Grard, Rejean; Lebreton, Jean-Pierre;

The peculiarities of power terrestrial ELF emission in the Earth's ionosphere

NASA Astrophysics Data System (ADS)

Korepanov, Valery; Dudkin, Fedir; Pronenko, Vira; Chvach, Valery

2016-04-01

The near-Earth space is saturated with electromagnetic (EM) waves of terrestrial origin in a wide frequency range. The most powerful natural sources of EM emission are thunderstorms and triggered by them Schumann resonance (SR) radiation which is the narrowband EM noise that occurs due to the global thunderstorm activity in the Earth-ionosphere cavity in frequency range about 7-100 Hz. The considerable part of the terrestrial EM emission belongs to everyday human activity which increases year by year with unpredictable consequences. At the beginning of space exploration era it was considered that high frequency EM waves freely penetrate through the Earth's ionosphere, but the terrestrial EM emission below very low frequency range is limited by ionospheric F2 layer boundary due to great EM losses in plasma. About 40 years ago the power lines harmonic radiation (multiple of 50/60 Hz) was found at satellite observations in a few kilohertz range, nevertheless the ionosphere was considered fully opaque for extremely low frequency (ELF) EM emission. However recently, in spite of theoretical estimations, the SR harmonics and power line emission (PLE) 50/60 Hz were discovered during flights of low Earth orbiting satellites C/NOFS (Simões et al., 2011) and Chibis-M (Dudkin et al., 2015) at heights 400-800 km, i.e. over F2-layer. Last results are a great challenge to the theory of ELF EM emission propagation in the Earth's ionosphere as well as for study of long-term influence of constantly increasing electric energy consumption by human civilization in the Earth's environment. We present the analysis of the space and time distribution for observed PLE and SR harmonics, their connection with power terrestrial sources of ELF emission and possible relation between measured values and ionosphere conditions. Also some electromagnetic parameters have been estimated. Simões, F. A., R. F. Pfaff, and H. T. Freudenreich (2011), Satellite observations of Schumann resonances in the Earth's ionosphere, Geophys. Res. Lett., 38, L22101, doi:10.1029/2011GL049668. Dudkin, F., V. Korepanov, D. Dudkin, V. Pilipenko, V. Pronenko, and S. Klimov (2015), Electric fi eld of the power terrestrial sources observed by microsatellite Chibis-M in the Earth ' s ionosphere in frequency range 1 - 60 Hz, Geophys. Res. Lett., 42, doi:10.1002/2015GL064595.

Neuronal Cellular Responses to Extremely Low Frequency Electromagnetic Field Exposure: Implications Regarding Oxidative Stress and Neurodegeneration

PubMed Central

Reale, Marcella; Kamal, Mohammad A.; Patruno, Antonia; Costantini, Erica; D'Angelo, Chiara; Pesce, Miko; Greig, Nigel H.

2014-01-01

Neurodegenerative diseases comprise both hereditary and sporadic conditions characterized by an identifying progressive nervous system dysfunction and distinctive neuopathophysiology. The majority are of non-familial etiology and hence environmental factors and lifestyle play key roles in their pathogenesis. The extensive use of and ever increasing worldwide demand for electricity has stimulated societal and scientific interest on the environmental exposure to low frequency electromagnetic fields (EMFs) on human health. Epidemiological studies suggest a positive association between 50/60-Hz power transmission fields and leukemia or lymphoma development. Consequent to the association between EMFs and induction of oxidative stress, concerns relating to development of neurodegenerative diseases, such as Alzheimer disease (AD), have been voiced as the brain consumes the greatest fraction of oxygen and is particularly vulnerable to oxidative stress. Exposure to extremely low frequency (ELF)-EMFs are reported to alter animal behavior and modulate biological variables, including gene expression, regulation of cell survival, promotion of cellular differentiation, and changes in cerebral blood flow in aged AD transgenic mice. Alterations in inflammatory responses have also been reported, but how these actions impact human health remains unknown. We hence evaluated the effects of an electromagnetic wave (magnetic field intensity 1mT; frequency, 50-Hz) on a well-characterized immortalized neuronal cell model, human SH-SY5Y cells. ELF-EMF exposure elevated the expession of NOS and O2 −, which were countered by compensatory changes in antioxidant catylase (CAT) activity and enzymatic kinetic parameters related to CYP-450 and CAT activity. Actions of ELF-EMFs on cytokine gene expression were additionally evaluated and found rapidly modified. Confronted with co-exposure to H2O2-induced oxidative stress, ELF-EMF proved not as well counteracted and resulted in a decline in CAT activity and a rise in O2 − levels. Together these studies support the further evaluation of ELF-EMF exposure in cellular and in vivo preclinical models to define mechanisms potentially impacted in humans. PMID:25127118

Unique concurrent observations of whistler mode hiss, chorus, and triggered emissions

NASA Astrophysics Data System (ADS)

Hosseini, Poorya; Gołkowski, Mark; Turner, Drew L.

2017-06-01

We present a unique 2 h ground-based observation of concurrent magnetospheric hiss, chorus, VLF triggered emissions as well as ELF/VLF signals generated locally by the High Frequency Active Auroral Research Program (HAARP) facility. Eccentricity of observed wave polarization is used as a criteria to identify magnetospheric emissions and estimate their ionospheric exit points. The observations of hiss and chorus in the unique background of coherent HAARP ELF/VLF waves and triggered emissions allow for more accurate characterization of hiss and chorus properties than in typical ground-based observations. Eccentricity and azimuth results suggest a moving ionospheric exit point associated with a single ducted path at L 5. The emissions exhibit dynamics in time suggesting an evolution of a magnetospheric source from hiss generation to chorus generation or a moving plasmapause location. We introduce a frequency band-limited autocorrelation method to quantify the relative coherency of the emissions. A range of coherency was observed from high order of coherency in local HAARP transmissions and their echoes to lower coherency in natural chorus and hiss emissions.

Ion resonances and ELF wave production by an electron beam injected into the ionosphere - ECHO 6

NASA Astrophysics Data System (ADS)

Winckler, J. R.; Steffen, J. E.; Malcolm, P. R.; Erickson, K. N.; Abe, Y.; Swanson, R. L.

1984-09-01

Two effects observed with electron antennas ejected from a sounding rocket launched into the ionosphere in March 1983 carrying electron beam guns are discussed. The sensor packages were ejected and travelled parallel to the vehicle trajectory. Electric potentials were measured between the single probes and a plasma diagnostic package while the gun injected electrons into the ionosphere in perpendicular and parallel 1 kHz directions. Signal pulses over the dc-1250 kHz range were detected. A kHz gun frequency caused a signal that decreased by two orders of magnitude between 45-90 m from the beam field line. However, the signal was detectable at 1 mV/m at 120 m, supporting earlier data that indicated that pulsed electron beams can cause ELF waves in space. Beam injection parallel to the magnetic field produced an 840 Hz resonance that could be quenched by activation of a transverse beam.

The Department of Defense Superconductivity Research and Development (DSRD) Options. A Study of Possible Directions for Exploitation of Superconductivity in Military Applications.

DTIC Science & Technology

1987-07-01

transmission lines Low - noise mm wave detectors, mixers and amplifiers Multi-GHz chirp transform processors High performance small antenna arrays Multi-GHz A/D...attractive alternative. The overall advantages for HTS mm wave receivers are very- low quantum-limited noise , wide bandwidth, low electrical power...0 0 3 2 1 6 6.3A 0 0 0 2 -3 S Total 2 2 4 S 4 17 116 10, ELF Communication (far term). Extremely low frequency communication via magnetic wave has

Measurement of electromagnetic waves in ELF and VLF bands to monitor lightning activity in the Maritime Continent

NASA Astrophysics Data System (ADS)

Yamashita, Kozo; Takahashi, Yukihiro; Ohya, Hiroyo; Tsuchiya, Fuminori; Sato, Mitsuteru; Matsumoto, Jun

2013-04-01

Data of lightning discharge has been focused on as an effective way for monitoring and nowcasting of thunderstorm activity which causes extreme weather. Spatial distribution of lightning discharge has been used as a proxy of the presence or absence of deep convection. Latest observation shows that there is extremely huge lightning whose scale is more than hundreds times bigger than that of averaged event. This result indicates that lightning observation should be carried out to estimate not only existence but also scale for quantitative evaluation of atmospheric convection. In this study, lightning observation network in the Maritime Continent is introduced. This network is consisted of the sensors which make possible to measure electromagnetic wave radiated from lightning discharges. Observation frequency is 0.1 - 40 kHz for the measurement of magnetic field and 1 - 40 kHz for that of electric field. Sampling frequency is 100 kHz. Waveform of electromagnetic wave is recorded by personal computer. We have already constructed observation stations at Tainan in Taiwan (23.1N, 121.1E), Saraburi in Thailand (14.5N, 101.0E), and Pontianak in Indonesia (0.0N, 109.4E). Furthermore, we plan to install the monitoring system at Los Banos in Philippines (14.18, 121.25E) and Hanoi in Viet Nam. Data obtained by multipoint observation is synchronized by GPS receiver installed at each station. By using data obtained by this network, location and scale of lightning discharge can be estimated. Location of lightning is determined based on time of arrival method. Accuracy of geolocation could be less than 10km. Furthermore, charge moment is evaluated as a scale of each lightning discharge. It is calculated from electromagnetic waveform in ELF range (3-30 kHz). At the presentation, we will show the initial result about geolocation for source of electromagnetic wave and derivation of charge moment value based on the measurement of ELF and VLF sferics.

Nonlinear interactions of electromagnetic waves with the auroral ionosphere

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wong, Alfred Y.

1999-09-20

The ionosphere provides us with an opportunity to perform plasma experiments in an environment with long confinement times, very large-scale lengths, and no confining walls. The auroral ionosphere with its nearly vertical magnetic field geometry is uniquely endowed with large amount of free energy from electron and ion precipitation along the magnetic field and mega-ampere current across the magnetic field. To take advantage of this giant outdoor laboratory, two facilities HAARP and HIPAS, with frequencies ranging from the radio to optical bands, are now available for active probing of and interaction with this interesting region. The ponderomotive pressures from themore » self-consistent wave fields have produced significant local perturbations of density and particle distributions at heights where the incident EM frequency matches a plasma resonance. This paper will review theory and experiments covering the nonlinear phenomena of parametric decay instability to wave collapse processes. At HF frequencies plasma lenses can be created by preconditioning pulses to focus what is a normally divergent beam into a high-intensity spot to further enhance nonlinear phenomena. At optical wavelengths a large rotating liquid metal mirror is used to focus laser pulses up to a given height. Such laser pulses are tuned to the same wavelengths of selected atomic and molecular resonances, with resulting large scattering cross sections. Ongoing experiments on dual-site experiments and excitation of ELF waves will be presented. The connection of such basic studies to environmental applications will be discussed. Such applications include the global communication using ELF waves, the ozone depletion and remediation and the control of atmospheric CO{sub 2} through the use of ion cyclotron resonant heating.« less

Nonlinear interactions of electromagnetic waves with the auroral ionosphere

NASA Astrophysics Data System (ADS)

Wong, Alfred Y.

1999-09-01

The ionosphere provides us with an opportunity to perform plasma experiments in an environment with long confinement times, very large-scale lengths, and no confining walls. The auroral ionosphere with its nearly vertical magnetic field geometry is uniquely endowed with large amount of free energy from electron and ion precipitation along the magnetic field and mega-ampere current across the magnetic field. To take advantage of this giant outdoor laboratory, two facilities HAARP and HIPAS, with frequencies ranging from the radio to optical bands, are now available for active probing of and interaction with this interesting region. The ponderomotive pressures from the self-consistent wave fields have produced significant local perturbations of density and particle distributions at heights where the incident EM frequency matches a plasma resonance. This paper will review theory and experiments covering the nonlinear phenomena of parametric decay instability to wave collapse processes. At HF frequencies plasma lenses can be created by preconditioning pulses to focus what is a normally divergent beam into a high-intensity spot to further enhance nonlinear phenomena. At optical wavelengths a large rotating liquid metal mirror is used to focus laser pulses up to a given height. Such laser pulses are tuned to the same wavelengths of selected atomic and molecular resonances, with resulting large scattering cross sections. Ongoing experiments on dual-site experiments and excitation of ELF waves will be presented. The connection of such basic studies to environmental applications will be discussed. Such applications include the global communication using ELF waves, the ozone depletion and remediation and the control of atmospheric CO2 through the use of ion cyclotron resonant heating.

Amplitude variations of ELF radio waves in the Earth-ionosphere cavity with the day-night non-uniformity

NASA Astrophysics Data System (ADS)

Galuk, Yu P.; Nickolaenko, A. P.; Hayakawa, M.

2018-04-01

The real structure of lower ionosphere should be taken into account when modeling the sub-ionospheric radio propagation in the extremely low frequency (ELF) band and studying the global electromagnetic (Schumann) resonance of the Earth-ionosphere cavity. In the present work we use the 2D (two dimensional) telegraph equations (2DTE) for evaluating the effect of the ionosphere day-night non-uniformity on the electromagnetic field amplitude at the Schumann resonance and higher frequencies. Properties of the cavity upper boundary were taken into account by the full wave solution technique for realistic vertical profiles of atmosphere conductivity in the ambient day and ambient night conditions. We solved the electromagnetic problem in a cavity with the day-night non-uniformity by using the 2DTE technique. Initially, the testing of the 2DTE solution was performed in the model of the sharp day-night interface. The further computations were carried out in the model of the smooth day-night transition. The major attention was directed to the effects at propagation paths "perpendicular" or "parallel" to the solar terminator line. Data were computed for a series of frequencies, the comparison of the results was made and interpretation was given to the observed effects.

Comment on "An Analysis of VLF Electric Field Spectra Measured in Titan's Atmosphere by The Huygens Probe" By J. A. Morente et al.

NASA Technical Reports Server (NTRS)

Grard, Rejean; Berthelin, Stephanie; Beghin, Christian; Hamelin, Michel; Berthelier, Jean-Jacques; Lopez-Moreno, Jose J.; Simoes, Fernando

2011-01-01

Morente et al. have recently revisited the VLF electric field measurements made with the Permittivity, Wave and Altimetry (PWA) instrument during the descent of the Huygens Probe through the atmosphere of Titan. They assert that they have identified several harmonics of the transverse resonance mode of the surface?]ionosphere cavity, which would prove the existence of an electrical activity in the atmosphere of the largest satellite of Saturn. We refute this finding on the basis that it results from an artifact due to an improper analysis of the data set. [2] The investigators of the Permittivity, Wave and Altimetry (PWA) experiment on the Huygens Probe have reported the extremely low frequency (ELF) and very low frequency (VLF) electric signals recorded during the descent through the atmosphere of Titan. The PWA data are archived in the Planetary Science Archive (PSA) of ESA, and an extensive description of the instrument is at the disposal of the scientific community. Morente and his coworkers have revisited this data set and reported the results of their investigations in two papers. In a first paper, they claim that they have detected in the ELF range (0.100 Hz) several harmonics of a global resonance allegedly generated by lightning activity in the spherical cavity guide formed by the surface of Titan and the inner boundary of the ionosphere, a phenomenon similar to the Schumann resonance observed at EartH In the second paper dedicated to the VLF electric signal recorded by PWA, in the range 0.10 kHz, they argue that they can also bring out the transverse resonance and its harmonics, a more local phenomenon that develops around the excitation source and whose frequency is controlled by the separation between Titan?fs surface and the inner ionospheric boundary. [3] The PWA investigators have analyzed the narrowband ELF signal at about 36 Hz effectively observed during the entire descent. They have not endorsed, however, the alternative approach of Morente et al. that discloses additional ELF narrow-band signals and numerous related harmonics. Hamelin et al. and Beghin et al. have questioned the work of Morente and his coworkers and demonstrated unambiguously that their findings are mere artifacts entirely due to a faulty procedure. Morente et al. refuted this critical analysis of their ELF paper in a rebuttal. The present comment draws a parallelism between the ELF and VLF papers and demonstrates that the VLF signal carries no evidence whatever of any transverse resonance. The analyses of the ELF and VLF signals by Morente and his coworkers are flawed, and their conclusions are shown here to be invalid. A more comprehensive and thorough assessment of the numerical approaches proposed by Morente et al. is given by Berthelin et al..

New Generation of ELF/VLF Wave Injection Experiments for HAARP

NASA Astrophysics Data System (ADS)

Sonwalkar, V. S.; Reddy, A.; Watkins, B. J.

2016-12-01

We present a ray tracing study to investigate the feasibility of a new generation of wave injection experiments from HAARP transmitter (L 4.9). Highly successful whistler mode wave injection experiments from SIPLE station, Antarctica, have established the importance of such experiments to study magnetospheric wave-particle interactions, and for cold and hot plasma diagnostics [Helliwell and Katsufrakis, 1974; Carpenter and Miller, 1976; Sonwalkar et al., 1997]. Modulated heating experiments from HAARP have shown that it is possible to launch ELF/VLF waves into the magnetosphere that can be observed on the ground after one-, two-, and multi-hop ducted propagation [Inan et al., 2004]. Recent research has also shown that ionospheric heating experiments using HAARP can lead to the formation of magnetospheric ducts [e.g. Milikh et al., 2010; Fallen et al., 2011]. Collectively, these results indicate that the HAARP (or similar) transmitter can be used first to form ducts on nearby L shells, and then to inject and trap transmitter generated ELF/VLF waves in those ducts. Ray tracing studies using a model magnetosphere shows that ELF/VLF waves in a few kilohertz range can be trapped in ducts with L shells near the HAARP transmitter. For example, 1.5 kHz waves injected from L shell = 4.9 and altitude = 200 km can be trapped in ducts located within 0.3 L of the transmitter L-shell. The duct parameters needed for ray-trapping are typically duct width dL 0.1-0.3 and duct enhancement factor dNe/Ne 10-20% or more. The location of plasmapause with respect to transmitter plays a role in the nature of trapping. The duct locations and parameters required for trapping ELF/VLF waves inside the ducts are consistent with past observations of ducts generated by the HAARP transmitter. Ray tracing calculations provide trapped wave normal angles, time delays, resonant energetic electron energy, estimates of wave intensity inside the duct, on the ground, and on satellites such DEMETER, Van Allen probe, and planned DSX. We discuss the potential of a new generation of wave injection experiments from HAARP transmitter to investigate: duct and ELF/VLF generation by high power HF transmitters, whistler mode wave propagation and wave particle interactions, and cold and hot plasma diagnostics.

Efficacy and safety evaluation of systemic extremely low frequency magnetic fields used in the healing of diabetic foot ulcers--phase II data.

PubMed

Cañedo-Dorantes, Luis; Soenksen, Luis R; García-Sánchez, Clara; Trejo-Núñez, Daphny; Pérez-Chávez, Fernando; Guerrero, Arturo; Cardona-Vicario, Melisa; García-Lara, Carlos; Collí-Magaña, Dianelly; Serrano-Luna, Gregorio; Angeles Chimal, José S; Cabrera, Guillermo

2015-08-01

Cellular and animal models investigating extremely low frequency magnetic fields (ELF-MF) have reported promotion of leukocyte-endothelial interactions, angiogenesis, myofibroblast and keratinocyte proliferation, improvement of peripheral neuropathy and diabetic wound healing. In humans, it has also been reported that systemic exposure to ELF-MF stimulates peripheral blood mononuclear cells, promoting angiogenesis and healing of chronic leg ulcers. The aim of the study was to investigate the effect of exposing different blood volumes to specific ELF-MFs (120 Hz sinusoidal waves of 0.4-0.9 mT RMS) to induce healing of diabetic foot ulcers (DFUs). Twenty six diabetic patients with non-responsive DFUs were divided into two exposure groups to receive treatment and record healing time. The forearm group, exposed to ELF-MF 2 h/day, twice weekly (3.6 l of blood/session); and the thorax group, exposed 25 min/day, 2 times/week (162.5 l of blood/session). Treatment period was 100 days or upon complete healing. Ulcer recurrences and adverse effects were investigated during short-term (<1 year) and long-term (3.4-7.8 years) follow-up. Mean healing time was 61.48 ± 33.08 days in the forearm group and 62.56 ± 29.33 days for the thorax group. No adverse effects or ulcer recurrences in the original ulcer site were reported during treatment, the short-term follow-up period or the long-term follow-up period in both groups. Healing time was independent of the amount of blood exposed to ELF-MF used in this trial. ELF-MFs are effective and safe and could be applied to non-healing DFUs in conjunction with other preventive interventions to reduce DFUs complications. Copyright © 2015 IMSS. Published by Elsevier Inc. All rights reserved.

Nonlinear wave-wave interactions in the subauroral ionosphere on the basis of ISIS-2 satellite observations of Siple station VLF signals

NASA Technical Reports Server (NTRS)

Ohnami, S.; Hayakawa, M.; Bell, T. F.; Ondoh, T.

1993-01-01

Nonlinear wave-wave interaction between signals from a ground-based VLF transmitter and narrow-band ELF emissions in the subauroral ionosphere is studied by means of the bispectrum and bicoherence analysis. A bicoherence analysis has indicated that the sideband structures around the Siple transmitter signal received onboard the ISIS satellite are due to the nonlinear interaction between the Siple VLF signal and the pre-existing ELF emission.

Extremely Low Frequency-Magnetic Field (ELF-MF) Exposure Characteristics among Semiconductor Workers

PubMed Central

Choi, Sangjun; Cha, Wonseok; Kim, Won; Yoon, Chungsik; Park, Ju-Hyun; Ha, Kwonchul; Park, Donguk

2018-01-01

We assessed the exposure of semiconductor workers to extremely low frequency-magnetic fields (ELF-MF) and identified job characteristics affecting ELF-MF exposure. These were demonstrated by assessing the exposure of 117 workers involved in wafer fabrication (fab) and chip packaging wearing personal dosimeters for a full shift. A portable device was used to monitor ELF-MF in high temporal resolution. All measurements were categorized by operation, job and working activity during working time. ELF-MF exposure of workers were classified based on the quartiles of ELF-MF distribution. The average levels of ELF-MF exposure were 0.56 µT for fab workers, 0.59 µT for chip packaging workers and 0.89 µT for electrical engineers, respectively. Exposure to ELF-MF differed among types of factory, operation, job and activity. Workers engaged in the diffusion and chip testing activities showed the highest ELF-MF exposure. The ELF-MF exposures of process operators were found to be higher than those of maintenance engineers, although peak exposure and/or patterns varied. The groups with the highest quartile ELF-MF exposure level are operators in diffusion, ion implantation, module and testing operations, and maintenance engineers in diffusion, module and testing operations. In conclusion, ELF-MF exposure among workers can be substantially affected by the type of operation and job, and the activity or location. PMID:29614730

Generation of VLF saucer emissions observed by the Viking satellite

NASA Astrophysics Data System (ADS)

Lonnqvist, H.; Andre, M.; Matson, L.; Bahnsen, A.; Blomberg, L. G.; Erlandson, R. E.

1993-08-01

Simultaneous observations by the Viking satellite of electric and magnetic fields as well as charged particles have been used to investigate V-shaped wave phenomena. The intensity of these VLF and ELF emissions is V-shaped when shown in a frequency versus time plot. Simultaneous observations of V-shaped so-called VLF saucer emissions, particles and field-aligned currents strongly suggest, for the first time, that upgoing electrons with energies less than a few hundred electron volts can generate these waves. Broadband waves observed inside the saucer generation region, from frequencies much less than the ion cyclotron frequency up to the plasma frequency, may also be generated by these electrons. Viking observations of VLF saucers at altitudes between 4000 km and 13,500 km show that these emissions occur at higher altitudes than discussed in previous reports. The generation regions seem to be more extended at these higher altitudes than what has been reported at lower altitudes by other observers.

VLF Remote Sensing of the Lower Ionosphere: Solar Flares, Electron Precipitation, Sudden Ionospheric Disturbances, Sprites, Gravity Waves and Gamma-ray Flares

NASA Astrophysics Data System (ADS)

Tan, J. H.; Cohen, M.; Inan, U. S.; Scherrer, P. H.; Scherrer, D.

2005-12-01

Stanford University Very Low Frequency (VLF) and Extremely Low Frequency (ELF) radio receivers have been used extensively for remote sensing of the ionosphere and the magnetosphere. Among the phenomena that can be uniquely measured via ELF/VLF receivers are radio atmospherics, whistlers, electron precipitation, solar flares, sudden ionospheric disturbances, gravity waves, sprites, and cosmic gamma-ray flares. With the use of simple square air-core magnetic loop antennas of a couple of meters in size, the sensitivity of these instruments allows the measurement of magnetic fields as low as several tens of femtoTesla per root-Hz, in the frequency range of ~30 Hz to 50 kHz. This sensitivity well exceeds that required to detect any event above the ambient atmospheric noise floor, determined by the totality of lightning activity on the planet. In recent years, as cost of production, timing accuracy (due to low cost GPS clocks), and data handling flexibility of the systems has improved, it has become possible to distribute many of these instruments in the form of arrays, to perform interferometric and holographic imaging of the lower ionosphere. In the context of the IHY in 2007, the ELF/VLF receiver can used extensively as part of the United Nations initiative to place scientific instruments in developing countries. Stanford University's past experiences setting up arrays of ELF/VLF receivers include an interferometer in Alaska, the Holographic Array for Ionospheric and Lightning research (HAIL) consisting of instruments at 13 different high schools in mid-western United States, a broader set of ELF/VLF receivers in Alaska, and various receivers abroad, including in France, Japan, Greece, Turkey, Ireland, and India. A global network of ELF/VLF receivers offer possibilities for a wide range of scientific topics, as well as serving as a means for educational outreach. These goals will be achieved using the newest version of the Stanford VLF receiver, known as AWESOME: Atmospheric Weather Educational System for Observation and Modeling of Electromagnetics. This new version is substantially lower in cost, and easier to set-up and use. Nevertheless, the receivers offer the same ultimate levels of resolution in time, sensitivity and dynamic range, as well as ease of handling of data that is used by researchers conducting cutting edge ionospheric and magnetospheric research. In this context, the placement of these systems at underdeveloped host countries provides an open-ended potential for exploration, limited only by the imagination and drive of the users. AWESOME monitors can be placed at schools, or universities, where they will serve the dual purpose of advancing scientific research, as well as providing a valuable tool for scientific education. Data collected can be pooled and publicly available to all the sites, strengthening the potential for both cooperative education and collaboration on the science between various regions and locations.

ELF/VLF wave propagation at subauroral latitudes: Conjugate observation between the ground and Van Allen Probes A

NASA Astrophysics Data System (ADS)

Martinez-Calderon, Claudia; Shiokawa, Kazuo; Miyoshi, Yoshizumi; Keika, Kunihiro; Ozaki, Mitsunori; Schofield, Ian; Connors, Martin; Kletzing, Craig; Hanzelka, Miroslav; Santolik, Ondrej; Kurth, William S.

2016-06-01

We report simultaneous observation of ELF/VLF emissions, showing similar spectral and frequency features, between a VLF receiver at Athabasca (ATH), Canada, (L = 4.3) and Van Allen Probes A (Radiation Belt Storm Probes (RBSP) A). Using a statistical database from 1 November 2012 to 31 October 2013, we compared a total of 347 emissions observed on the ground with observations made by RBSP in the magnetosphere. On 25 February 2013, from 12:46 to 13:39 UT in the dawn sector (04-06 magnetic local time (MLT)), we observed a quasiperiodic (QP) emission centered at 4 kHz, and an accompanying short pulse lasting less than a second at 4.8 kHz in the dawn sector (04-06 MLT). RBSP A wave data showed both emissions as right-hand polarized with their Poynting vector earthward to the Northern Hemisphere. Using cross-correlation analysis, we did, for the first time, time delay analysis of a conjugate ELF/VLF event between ground and space, finding +2 to +4 s (ATH first) for the QP and -3 s (RBSP A first) for the pulse. Using backward tracing from ATH to the geomagnetic equator and forward tracing from the equator to RBSP A, based on plasmaspheric density observed by the spacecraft, we validate a possible propagation path for the QP emission which is consistent with the observed time delay.

ELF waves and ion resonances produced by an electron beam emitting rocket in the ionosphere

NASA Technical Reports Server (NTRS)

Winckler, J. R.; Abe, Y.; Erickson, K. N.

1986-01-01

Results are reported from the ECHO-6 electron-beam-injection experiment, performed in the auroral-zone ionosphere on March 30, 1983 using a sounding rocket equipped with two electron guns and a free-flying plasma-diagnostics instrument package. The data are presented in extensive graphs and diagrams and characterized in detail. Large ELF wave variations, superposed on the strong beam-sector-directed quasi-dc component, are observed in the 100-eV beam-induced plasma when the beam is injected in a transverse spiral, but not when it is injected upward parallel to the magnetic-field line. ELF activity is found to be suppressed whenever the rocket passed through field lines with auroral activity, suggesting that the waves are produced by the interaction of the beam potentials, plasma currents, and return currents neutralizing the accelerator payload.

ELF whistler events with a reduced intensity observed by the DEMETER spacecraft

NASA Astrophysics Data System (ADS)

Zahlava, J.; Nemec, F.; Santolik, O.; Kolmasova, I.; Parrot, M.

2017-12-01

A survey of VLF frequency-time spectrograms obtained by the DEMETER spacecraft (2004-2010, altitude about 700 km) revealed that the intensity of fractional hop whistlers is sometimes significantly reduced at specific frequencies. These frequencies are typically above about 3.4 kHz (second cutoff frequency of the Earth-ionosphere waveguide), and they vary smoothly in time. The events were explained by the wave propagation in the Earth-ionosphere waveguide, and a resulting interference of the first few waveguide modes. We analyze the events whose frequency-time structure is rather similar, but at frequencies below 1 kHz. Altogether, 284 events are identified during the periods with active Burst mode, when high resolution data are measured by DEMETER. The vast majority of events (93%) occurs during the nighttime. All six electromagnetic field components are available, which allows us to perform a detailed wave analysis. An overview of the properties of these events is presented, and their possible origin is discussed.

Cellular and molecular pathways of extremely-low-frequency electromagnetic field interactions with living systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tenforde, T.S.

1992-06-01

There is growing evidence that environmental electric and magnetic fields in the extremely-low-frequency (ELF) band below 300 Hz can influence biological functions by mechanisms that are only poorly understood at the present time. The primary objectives of this paper are to review the physical properties of ELF fields, their interactions with living systems at the tissue, cellular, and subcellular levels, and the key role of cell membranes ;in the transduction of signals from imposed ELF fields. Topics of discussion include signal-to-noise ratios for single cells and cell aggregates, resonance phenomena involving a combination of static and ELF magnetic fields, andmore » the possible influence of ELF fields on molecular signaling pathways that involve membrane receptors and cytoplasmic second messengers.« less

HAARP-based Investigations of Lightning-induced Nonlinearities within the D-Region Ionosphere

NASA Astrophysics Data System (ADS)

Moore, R. C.

2015-12-01

It is well-documented that energetic lightning can produce fantastical events with the lower ionosphere. Although the High-frequency Active Auroral Research Program (HAARP) transmitter is not as powerful as lightning, it can be used to investigate the nonlinear interactions that occur within the lower ionosphere, many of which also occur during lightning-induced ionospheric events. This paper presents the best experimental results obtained during D-region modification experiments performed by the University of Florida at the HAARP observatory between 2007 and 2014, including ELF/VLF wave generation experiments, wave-wave mixing experiments, and cross-modulation experiments. We emphasize the physical processes important for lightning-ionosphere interactions that can be directly investigated using HAARP.

High Power Radio Wave Interactions within the D-Region Ionosphere

NASA Astrophysics Data System (ADS)

Moore, R. C.

2014-12-01

This paper highlights the best results obtained during D-region modification experiments performed by the University of Florida at the High-frequency Active Auroral Research Program (HAARP) observatory between 2007 and 2014. Over this period, we have seen a tremendous improvement in ELF/VLF wave generation efficiency. We have identified methods to characterize ambient and modified ionospheric properties and to discern and quantify specific types of interactions. We have demonstrated several important implications of HF cross-modulation effects, including "Doppler Spoofing" on HF radio waves. Throughout this talk, observations are compared with the predictions of an ionospheric HF heating model to provide context and guidance for future D-region modification experiments.

The effects of different intensities, frequencies and exposure times of extremely low-frequency electromagnetic fields on the growth of Staphylococcus aureus and Escherichia coli O157:H7.

PubMed

Bayır, Ece; Bilgi, Eyüp; Şendemir-Ürkmez, Aylin; Hameş-Kocabaş, E Esin

2015-03-01

The impact of different types of extremely low-frequency electromagnetic fields (ELF-EMF) on the growth of Staphylococcus aureus and Escherichia coli O157:H7 was investigated. The cultures of bacteria in broth media were exposed to sinusoidal homogenous ELF-EMF with 2 and 4 mT magnetic intensities. Each intensity for each bacteria was combined with three different frequencies (20, 40 and 50 Hz), and four different exposure times (1, 2, 4 and 6 h). A cell suspension of each experiment was diluted for the appropriate range and inoculated to Mueller-Hinton Agar (MHA) plates after exposure to ELF-EMF. The number of colony forming units (CFU) of both strains was obtained after incubation at 37 °C for 24 h. Data were statistically evaluated by one-way analysis of variance (ANOVA), statistical significance was described at p < 0.05 and data were compared with their non-exposed controls. Magnetic intensity, frequency and exposure time of ELF-EMFs changed the characteristic responses for both microorganisms. Samples exposed to ELF-EMF showed a statistically significant decrease compared to their controls in colony forming capability, especially at long exposure times. An exposure to 4 mT-20 Hz ELF-EMF of 6 h produced maximum inhibition of CFU compared to their controls for both microorganisms (95.2% for S. aureus and 85% for E. coli).

Extremely low-frequency electromagnetic field influences the survival and proliferation effect of human adipose derived stem cells.

PubMed

Razavi, Shahnaz; Salimi, Marzieh; Shahbazi-Gahrouei, Daryoush; Karbasi, Saeed; Kermani, Saeed

2014-01-01

Extremely low-frequency electromagnetic fields (ELF-EMF) can effect on biological systems and alters some cell functions like proliferation rate. Therefore, we aimed to attempt the evaluation effect of ELF-EMF on the growth of human adipose derived stem cells (hADSCs). ELF-EMF was generated by a system including autotransformer, multi-meter, solenoid coils, teslameter and its probe. We assessed the effect of ELF-EMF with intensity of 0.5 and 1 mT and power line frequency 50 Hz on the survival of hADSCs for 20 and 40 min/day for 7 days by MTT assay. One-way analysis of variance was used to assessment the significant differences in groups. ELF-EMF has maximum effect with intensity of 1 mT for 20 min/day on proliferation of hADSCs. The survival and proliferation effect (PE) in all exposure groups were significantly higher than that in sham groups (P < 0.05) except in group of 1 mT and 40 min/day. Our results show that between 0.5 m and 1 mT ELF-EMF could be enhances survival and PE of hADSCs conserving the duration of exposure.

REPRODUCTIVE AND DEVELOPMENTAL EFFECTS IN MAMMALIAN AND AVIAN SPECIES FROM EXPOSURE TO ELF (EXTREMELY LOW FREQUENCY) FIELDS

EPA Science Inventory

This paper critically reviews the Extremely Low Frequency (ELF) Electromagnetic Fields literature from 1978 to the present in regard to research dealing with the reproductive and developmental effects of exposure.

Shear Alfven Wave Injection in the Magnetosphere by Ionospheric Modifications in the Absence of Electrojet Currents

NASA Astrophysics Data System (ADS)

Papadopoulos, K.; Eliasson, B.; Shao, X.; Labenski, J.; Chang, C.

2011-12-01

A new concept of generating ionospheric currents in the ULF/ELF range with modulated HF heating using ground-based transmitters even in the absence of electrojet currents is presented. The new concept relies on using HF heating of the F-region to modulate the electron temperature and has been given the name Ionospheric Current Drive (ICD). In ICD, the pressure gradient associated with anomalous or collisional F-region electron heating drives a local diamagnetic current that acts as an antenna to inject mainly Magneto-Sonic (MS) waves in the ionospheric plasma. The electric field associated with the MS wave drives Hall currents when it reaches the E region of the ionosphere. The Hall currents act as a secondary antenna that inject waves in the Earth-Ionosphere Waveguide (EIW) below and shear Alfven waves or EMIC waves upwards towards the conjugate regions. The paper presents: (i) Theoretical results using a cold Hall MHD model to study ICD and the generation of ULF/ELF waves by the modulation of the electron pressure at the F2-region with an intense HF electromagnetic wave. The model solves equations governing the dynamics of the shear Alfven and magnetosonic modes, of the damped modes in the diffusive Pedersen layer, and of the weakly damped helicon wave mode in the Hall-dominated E-region. The model incorporates realistic profile of the ionospheric conductivities and magnetic field configuration. We use the model to simulate propagation and dynamics of the low-frequency waves and their injection into the magnetosphere from the HAARP and Arecibo ionospheric heaters. (ii) Proof of principle experiments using the HAARP ionospheric heater in conjunction with measurements by the DEMETER satellite This work is supported by ONR MURI grant and DARPA BRIOCHE Program

The ELF in Your Library.

ERIC Educational Resources Information Center

McKimmie, Tim; Smith, Jeanette

1994-01-01

Presents an overview of the issues related to extremely low frequency (ELF) radiation from computer video display terminals. Highlights include electromagnetic fields; measuring ELF; computer use in libraries; possible health effects; electromagnetic radiation; litigation and legislation; standards and safety; and what libraries can do. (Contains…

Trends in residential exposure to electromagnetic fields from 2006 to 2009.

PubMed

Tomitsch, J; Dechant, E

2012-05-01

After measuring extremely low frequency electric and magnetic fields (ELF-EFs, ELF-MFs) and radio frequency electromagnetic fields (RF-EMFs) in 2006, a follow-up investigation was done in 2009. Overall, 130 measurements in bedrooms at identical and 83 at changed locations within the same or a neighbouring building were performed. The median of ELF-EFs decreased from 25.15 to 17.35 V m(-1) from 2006 to 2009. The median of all-night ELF-MFs from power supply decreased from 16.86 to 12.76 nT, whereas the arithmetic mean was almost unchanged (+0.1%). No difference in the medians of all-night ELF-MFs of railway current was observed. RF-EMFs increased from 41.35 to 59.56 µW m(-2). Increases primarily occurred in the frequency ranges of Global System for Mobile 900 MHz, Universal Mobile Telecommunications System and Wireless Local Area Network. Television changeover from analogue to digital resulted in a reduction within the Ultra-high Frequency-band from 0.47 to 0.35 µW m(-2). The base stations of the recently established terrestrial trunked radio system caused a median of 0.05 µW m(-2).

Extremely Low-Frequency Electromagnetic Fields Promote In Vitro Neuronal Differentiation and Neurite Outgrowth of Embryonic Neural Stem Cells via Up-Regulating TRPC1

PubMed Central

Ma, Qinlong; Chen, Chunhai; Deng, Ping; Zhu, Gang; Lin, Min; Zhang, Lei; Xu, Shangcheng; He, Mindi; Lu, Yonghui; Duan, Weixia; Pi, Huifeng; Cao, Zhengwang; Pei, Liping; Li, Min; Liu, Chuan; Zhang, Yanwen; Zhong, Min; Zhou, Zhou; Yu, Zhengping

2016-01-01

Exposure to extremely low-frequency electromagnetic fields (ELF-EMFs) can enhance hippocampal neurogenesis in adult mice. However, little is focused on the effects of ELF-EMFs on embryonic neurogenesis. Here, we studied the potential effects of ELF-EMFs on embryonic neural stem cells (eNSCs). We exposed eNSCs to ELF-EMF (50 Hz, 1 mT) for 1, 2, and 3 days with 4 hours per day. We found that eNSC proliferation and maintenance were significantly enhanced after ELF-EMF exposure in proliferation medium. ELF-EMF exposure increased the ratio of differentiated neurons and promoted the neurite outgrowth of eNSC-derived neurons without influencing astrocyes differentiation and the cell apoptosis. In addition, the expression of the proneural genes, NeuroD and Ngn1, which are crucial for neuronal differentiation and neurite outgrowth, was increased after ELF-EMF exposure. Moreover, the expression of transient receptor potential canonical 1 (TRPC1) was significantly up-regulated accompanied by increased the peak amplitude of intracellular calcium level induced by ELF-EMF. Furthermore, silencing TRPC1 expression eliminated the up-regulation of the proneural genes and the promotion of neuronal differentiation and neurite outgrowth induced by ELF-EMF. These results suggest that ELF-EMF exposure promotes the neuronal differentiation and neurite outgrowth of eNSCs via up-regulation the expression of TRPC1 and proneural genes (NeuroD and Ngn1). These findings also provide new insights in understanding the effects of ELF-EMF exposure on embryonic brain development. PMID:26950212

Effects of 100-μT extremely low frequency electromagnetic fields exposure on hematograms and blood chemistry in rats

PubMed Central

Lai, Jinsheng; Zhang, Yemao; Zhang, Jiangong; Liu, Xingfa; Ruan, Guoran; Chaugai, Sandip; Tang, Jiarong; Wang, Hong; Chen, Chen; Wang, Dao Wen

2016-01-01

The aim of this study was to test whether extremely low frequency electromagnetic fields (ELF EMFs) affect health or not. Here, we constructed a 100-μT/50 Hz electromagnetic field atmosphere. A total of 128 rats were randomly assigned into two groups: the ELF EMF group and the sham group. The ELF EMF group was exposed to 100-μT/50-Hz ELF EMF for 20 h per day for three months; at the same time the other group was exposed to a sham device without ELF EMF. During the three months, the weight was recorded every 2 weeks, and the water intake and food intake of the animals were recorded weekly. The hematologic parameters were detected before and after the exposure, whereas blood chemistry analysis was performed every 4 weeks. The general condition of the exposed rats was not affected by ELF EMF. Compared with the sham group, the hematograms were not significantly altered in the ELF EMF group. Similarly, the blood chemistry (including lipid profile, blood glucose, liver function and renal function of rats) from the ELF EMF group showed no difference compared with rats from the control group during the three months exposure. The present study indicated that short-term exposure of 100-μT/50-Hz ELF EMF may not affect hematograms and blood chemistry in rats. PMID:26404558

Extremely low frequency electromagnetic field (ELF-EMF) reduces oxidative stress and improves functional and psychological status in ischemic stroke patients.

PubMed

Cichoń, Natalia; Bijak, Michał; Miller, Elżbieta; Saluk, Joanna

2017-07-01

As a result of ischaemia/reperfusion, massive generation of reactive oxygen species occurs, followed by decreased activity of antioxidant enzymes. Extremely low frequency electromagnetic fields (ELF-EMF) can modulate oxidative stress, but there are no clinical antioxidant studies in brain stroke patients. The aim of our study was to investigate the effect of ELF-EMF on clinical and antioxidant status in post-stroke patients. Fifty-seven patients were divided into two groups: ELF-EMF and non-ELF-EMF. Both groups underwent the same 4-week rehabilitation program. Additionally, the ELF-EMF group was exposed to an ELF-EMF field of 40 Hz, 7 mT for 15 min/day for 4 weeks (5 days a week). The activity of catalase and superoxide dismutase was measured in hemolysates, and total antioxidant status (TAS) determined in plasma. Functional status was assessed before and after the series of treatments using Activities of Daily Living (ADL), Mini-Mental State Examination (MMSE), and Geriatric Depression Scale (GDS). Applied ELF-EMF significantly increased enzymatic antioxidant activity; however, TAS levels did not change in either group. Results show that ELF-EMF induced a significant improvement in functional (ADL) and mental (MMSE, GDS) status. Clinical parameters had positive correlation with the level of enzymatic antioxidant protection. Bioelectromagnetics. 38:386-396, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Exposure system to study hypotheses of ELF and RF electromagnetic field interactions of mobile phones with the central nervous system.

PubMed

Murbach, Manuel; Christopoulou, Maria; Crespo-Valero, Pedro; Achermann, Peter; Kuster, Niels

2012-09-01

A novel exposure system for double-blind human electromagnetic provocation studies has been developed that satisfies the precision, control of fields and potential artifacts, and provides the flexibility to investigate the response of hypotheses-driven electromagnetic field exposure schemes on brain function, ranging from extremely low frequency (ELF) to radio frequency (RF) fields. The system can provide the same exposure of the lateral cerebral cortex at two different RF frequencies (900 and 2140 MHz) but with different exposure levels at subcortical structures, and also allows uniform ELF magnetic field exposure of the brain. The RF modulation and ELF signal are obtained by a freely programmable arbitrary signal generator allowing a wide range of worst-case exposure scenarios to be simulated, including those caused by wireless devices. The maximum achievable RF exposure is larger than 60 W/kg peak spatial specific absorption rate averaged over 10 g of tissue. The maximum ELF magnetic field exposure of the brain is 800 A/m at 50 Hz with a deviation from uniformity of 8% (SD). Copyright © 2012 Wiley Periodicals, Inc.

Extremely low-frequency electromagnetic field influences the survival and proliferation effect of human adipose derived stem cells

PubMed Central

Razavi, Shahnaz; Salimi, Marzieh; Shahbazi-Gahrouei, Daryoush; Karbasi, Saeed; Kermani, Saeed

2014-01-01

Background: Extremely low-frequency electromagnetic fields (ELF-EMF) can effect on biological systems and alters some cell functions like proliferation rate. Therefore, we aimed to attempt the evaluation effect of ELF-EMF on the growth of human adipose derived stem cells (hADSCs). Materials and Methods: ELF-EMF was generated by a system including autotransformer, multi-meter, solenoid coils, teslameter and its probe. We assessed the effect of ELF-EMF with intensity of 0.5 and 1 mT and power line frequency 50 Hz on the survival of hADSCs for 20 and 40 min/day for 7 days by MTT assay. One-way analysis of variance was used to assessment the significant differences in groups. Results: ELF-EMF has maximum effect with intensity of 1 mT for 20 min/day on proliferation of hADSCs. The survival and proliferation effect (PE) in all exposure groups were significantly higher than that in sham groups (P < 0.05) except in group of 1 mT and 40 min/day. Conclusion: Our results show that between 0.5 m and 1 mT ELF-EMF could be enhances survival and PE of hADSCs conserving the duration of exposure. PMID:24592372

Nonlinear Interactions within the D-Region Ionosphere

NASA Astrophysics Data System (ADS)

Moore, Robert

2016-07-01

This paper highlights the best results obtained during D-region modification experiments performed by the University of Florida at the High-frequency Active Auroral Research Program (HAARP) observatory between 2007 and 2014. Over this period, we saw a tremendous improvement in ELF/VLF wave generation efficiency. We identified methods to characterize ambient and modified ionospheric properties and to discern and quantify specific types of interactions. We have demonstrated several important implications of HF cross-modulation effects, including "Doppler Spoofing" on HF radio waves. Throughout this talk, observations are compared with the predictions of an ionospheric HF heating model to provide context and guidance for future D-region modification experiments.

ELF and VLF signatures of sprites registered onboard the low altitude satellite DEMETER

NASA Astrophysics Data System (ADS)

Błecki, J.; Parrot, M.; Wronowski, R.

2009-06-01

We report the observation of ELF and VLF signature of sprites recorded on the low altitude satellite DEMETER during thunderstorm activity. At an altitude of ~700 km, waves observed on the E-field spectrograms at mid-to-low latitudes during night time are mainly dominated by up-going 0+ whistlers. During the night of 20 July 2007 two sprites have been observed around 20:10:08 UT from the observatory located on the top of the mountain Śnieżka in Poland (50°44'09" N, 15°44'21" E, 1603 m) and, ELF and VLF data have been recorded by the satellite at about 1200 km from the region of thunderstorm activity. During this event, the DEMETER instruments were switched in the burst mode and it was possible to register the wave forms. It is shown that the two sprites have been triggered by two intense +CG lightning strokes (100 kA) occurring during the same millisecond but not at the same location. Despite the distance DEMETER has recorded at the same time intense and unusual ELF and VLF emissions. It is shown that the whistler wave propagates from the thunderstorm regions in the Earth-ionosphere guide and enters in the ionosphere below the satellite. They last several tens of milliseconds and the intensity of the ELF waveform is close to 1 mV/m. A particularly intense proton whistler is also associated with these emissions.

ELF Field Strength Measurements Made in Connecticut During 1974

DTIC Science & Technology

1975-10-01

Ionospheric Phenomena on Extremely Low Frequency ( ELF ) Propagation," IEEE Transactions on Communications , vol. COM-22, no. 4, 1974, pp. 484-492...34f" ""WW" I I W»*-«P ’^ AD-A016 795 ELF FIELD STRENGTH MEASUREMENTS MADE IN CONNECTICUT DURING 1974 Peter R. Bannister...Report 4927 CD rH O ELF Field Strength Measurements Made In Connecticut During 1974 PETER R. BANNISTER FREDERICK J. WILLIAMS Submarin

Effects of aluminum and extremely low frequency electromagnetic radiation on oxidative stress and memory in brain of mice.

PubMed

Deng, Yuanxin; Zhang, Yanwen; Jia, Shujie; Liu, Junkang; Liu, Yanxia; Xu, Weiwei; Liu, Lei

2013-12-01

This study was aimed to investigate the effect of aluminum and extremely low-frequency magnetic fields (ELF-MF) on oxidative stress and memory of SPF Kunming mice. Sixty male SPF Kunming mice were divided randomly into four groups: control group, ELF-MF group (2 mT, 4 h/day), load aluminum group (200 mg aluminum/kg, 0.1 ml/10 g), and ELF-MF + aluminum group (2 mT, 4 h/day, 200 mg aluminum/kg). After 8 weeks of treatment, the mice of three experiment groups (ELF-MF group, load aluminum group, and ELF-MF + aluminum group) exhibited firstly the learning memory impairment, appearing that the escaping latency to the platform was prolonged and percentage in the platform quadrant was reduced in the Morris water maze (MWM) task. Secondly are the pathologic abnormalities including neuronal cell loss and overexpression of phosphorylated tau protein in the hippocampus and cerebral cortex. On the other hand, the markers of oxidative stress were determined in mice brain and serum. The results showed a statistically significant decrease in superoxide dismutase activity and increase in the levels of malondialdehyde in the ELF-MF group (P < 0.05 or P < 0.01), load aluminum group (P < 0.01), and ELF-MF + aluminum group (P < 0.01). However, the treatment with ELF-MF + aluminum induced no more damage than ELF-MF and aluminum did, respectively. In conclusion, both aluminum and ELF-MF could impact on learning memory and pro-oxidative function in Kunming mice. However, there was no evidence of any association between ELF-MF exposure with aluminum loading.

Extremely Low-Frequency Electromagnetic Fields Cause G1 Phase Arrest through the Activation of the ATM-Chk2-p21 Pathway

PubMed Central

Huang, Chao-Ying; Chang, Cheng-Wei; Chen, Chaang-Ray; Chuang, Chun-Yu; Chiang, Chi-Shiun; Shu, Wun-Yi; Fan, Tai-Ching; Hsu, Ian C.

2014-01-01

In daily life, humans are exposed to the extremely low-frequency electromagnetic fields (ELF-EMFs) generated by electric appliances, and public concern is increasing regarding the biological effects of such exposure. Numerous studies have yielded inconsistent results regarding the biological effects of ELF-EMF exposure. Here we show that ELF-EMFs activate the ATM-Chk2-p21 pathway in HaCaT cells, inhibiting cell proliferation. To present well-founded results, we comprehensively evaluated the biological effects of ELF-EMFs at the transcriptional, protein, and cellular levels. Human HaCaT cells from an immortalized epidermal keratinocyte cell line were exposed to a 1.5 mT, 60 Hz ELF-EMF for 144 h. The ELF-EMF could cause G1 arrest and decrease colony formation. Protein expression experiments revealed that ELF-EMFs induced the activation of the ATM/Chk2 signaling cascades. In addition, the p21 protein, a regulator of cell cycle progression at G1 and G2/M, exhibited a higher level of expression in exposed HaCaT cells compared with the expression of sham-exposed cells. The ELF-EMF-induced G1 arrest was diminished when the CHK2 gene expression (which encodes checkpoint kinase 2; Chk2) was suppressed by specific small interfering RNA (siRNA). These findings indicate that ELF-EMFs activate the ATM-Chk2-p21 pathway in HaCaT cells, resulting in cell cycle arrest at the G1 phase. Based on the precise control of the ELF-EMF exposure and rigorous sham-exposure experiments, all transcriptional, protein, and cellular level experiments consistently supported the conclusion. This is the first study to confirm that a specific pathway is triggered by ELF-EMF exposure. PMID:25111195

Interharmonic modulation products as a means to quantify nonlinear D-region interactions

NASA Astrophysics Data System (ADS)

Moore, Robert

Experimental observations performed during dual beam ionospheric HF heating experiments at the High frequency Active Auroral Research Program (HAARP) HF transmitter in Gakona, Alaska are used to quantify the relative importance of specific nonlinear interactions that occur within the D region ionosphere. During these experiments, HAARP broadcast two amplitude modulated HF beams whose center frequencies were separated by less than 20 kHz. One beam was sinusoidally modulated at 500 Hz while the second beam was sinusoidally modulated using a 1-7 kHz linear frequency-time chirp. ELF/VLF observations performed at two different locations (3 and 98 km from HAARP) provide clear evidence of strong interactions between all field components of the two HF beams in the form of low and high order interharmonic modulation products. From a theoretical standpoint, the observed interharmonic modulation products could be produced by several different nonlinearities. The two primary nonlinearities take the form of wave-medium interactions (i.e., cross modulation), wherein the ionospheric conductivity modulation produced by one signal crosses onto the other signal via collision frequency modification, and wave-wave interactions, wherein the conduction current associated with one wave mixes with the electric field of the other wave to produce electron temperature oscillations. We are able to separate and quantify these two different nonlinearities, and we conclude that the wave-wave interactions dominate the wave-medium interactions by a factor of two. These results are of great importance for the modeling of transioinospheric radio wave propagation, in that both the wave-wave and the wave-medium interactions could be responsible for a significant amount of anomalous absorption.

Survey of electromagnetic field exposure in bedrooms of residences in lower Austria.

PubMed

Tomitsch, Johannes; Dechant, Engelbert; Frank, Wilhelm

2010-04-01

Previous investigations of exposure to electric, magnetic, or electromagnetic fields (EMF) in households were either about electricity supply EMFs or radio frequency EMFs (RF-EMFs). We report results from spot measurements at the bedside that comprise electrostatic fields, extremely low-frequency electric fields (ELF-EFs), extremely low-frequency magnetic fields (ELF-MFs), and RF-EMFs. Measurements were taken in 226 households throughout Lower Austria. In addition, effects of simple reduction measures (e.g., removal of clock radios or increasing their distance from the bed, turning off Digital Enhanced Cordless Telecommunication (DECT) telephone base stations) were assessed. All measurements were well below International Commission on Non-Ionizing Radiation Protection (ICNIRP) guideline levels. Average night-time ELF-MFs (long-term measurement from 10 pm to 6 am, geometric mean over households) above 100 nT were obtained in 2.3%, and RF-EMFs above 1000 microW/m(2) in 7.1% of households. Highest ELF-EFs were primarily due to lamps beside the bed (max = 166 V/m), and highest ELF-MFs because of transformers of devices (max = 1030 nT) or high current of power lines (max = 380 nT). The highest values of RF-EMFs were caused by DECT telephone base stations (max = 28979 microW/m(2)) and mobile phone base stations (max = 4872 microW/m(2)). Simple reduction measures resulted in an average decrease of 23 nT for ELF-MFs, 23 V/m for ELF-EFs, and 246 microW/m(2) for RF-EMFs. A small but statistically significant correlation between ELF-MF exposure and overall RF-EMF levels of R = 0.16 (P = 0.008) was computed that was independent of type (flat, single family) and location (urban, rural) of houses. (c) 2009 Wiley-Liss, Inc.

ELF propagation in the plasmasphere based on satellite observations of discrete and continuous forms

NASA Technical Reports Server (NTRS)

Muzzio, J. L. R.

1971-01-01

The propagation of electromagnetic waves in a nonhomogeneous anisotropic medium is examined from the point of view of geometrical optics. In particular, the propagation of ELF waves in the magnetosphere is described in terms of the electron and ion densities and the intensity and inclination of the earth's magnetic field. The analysis of the variations of wave normal angle along the ray path is extended to include the effects of ions. A comparison of the relative importance of each of the above parameters in controlling the orientation of the wave normals is made in the region of the magnetosphere where most of the ion whistlers have been detected.

Generation of Shear Alfvén Waves by Repetitive High Power Microwave Pulses Near the Electron Plasma Frequency - A laboratory study of a ``Virtual Antenna''

NASA Astrophysics Data System (ADS)

Wang, Yuhou; Gekelman, Walter; Pribyl, Patrick; van Compernolle, Bart; Papadopoulos, Konstantinos

2015-11-01

ELF / ULF waves are important in terrestrial radio communications but difficult to launch using ground-based structures due to their enormous wavelengths. In spite of this generation of such waves by field-aligned ionospheric heating modulation was first demonstrated using the HAARP facility. In the future heaters near the equator will be constructed and laboratory experiments on cross-field wave propagation could be key to the program's success. Here we report a detailed laboratory study conducted on the Large Plasma Device (LaPD) at UCLA. In this experiment, ten rapid pulses of high power microwaves (250 kW X-band) near the plasma frequency were launched transverse to the background field, and were modulated at a variable fraction (0.1-1.0) of fci. Along with bulk electron heating and density modification, the microwave pulses generated a population of fast electrons. The field-aligned current carried by the fast electrons acted as an antenna that radiated shear Alfvén waves. It was demonstrated that a controllable arbitrary frequency (f

Extremely low frequency (ELF) stray magnetic fields of laboratory equipment: a possible co-exposure conducting experiments on cell cultures.

PubMed

Gresits, Iván; Necz, Péter Pál; Jánossy, Gábor; Thuróczy, György

2015-09-01

Measurements of extremely low frequency (ELF) magnetic fields were conducted in the environment of commercial laboratory equipment in order to evaluate the possible co-exposure during the experimental processes on cell cultures. Three types of device were evaluated: a cell culture CO2 incubator, a thermostatic water bath and a laboratory shaker table. These devices usually have electric motors, heating wires and electronic control systems, therefore may expose the cell cultures to undesirable ELF stray magnetic fields. Spatial distributions of magnetic field time domain signal waveform and frequency spectral analysis (FFT) were processed. Long- and short-term variation of stray magnetic field was also evaluated under normal use of investigated laboratory devices. The results show that the equipment under test may add a considerable ELF magnetic field to the ambient environmental magnetic field or to the intentional exposure to ELF, RF or other physical/chemical agents. The maximum stray magnetic fields were higher than 3 µT, 20 µT and 75 µT in the CO2 incubator, in water bath and on the laboratory shaker table, respectively, with high variation of spatial distribution and time domain. Our investigation emphasizes possible confounding factors conducting cell culture studies related to low-level ELF-EMF exposure due to the existing stray magnetic fields in the ambient environment of laboratory equipment.

Extremely Low Frequency Electromagnetic Field from Convective Air Warming System on Temperature Selection and Distance.

PubMed

Cho, Kwang Rae; Kim, Myoung-Hun; Ko, Myoung Jin; Jung, Jae Wook; Lee, Ki Hwa; Park, Yei-Heum; Kim, Yong Han; Kim, Ki Hoon; Kim, Jin Soo

2014-12-01

Hypothermia generates potentially severe complications in operating or recovery room. Forced air warmer is effective to maintain body temperature. Extremely low frequency electromagnetic field (ELF-EMF) is harmful to human body and mainly produced by electronic equipment including convective air warming system. We investigated ELF-EMF from convective air warming device on various temperature selection and distance for guideline to protect medical personnel and patients. The intensity of ELF-EMF was measured as two-second interval for five minutes on various distance (0.1, 0.2, 0.3, 0.5 and 1meter) and temperature selection (high, medium, low and ambient). All of electrical devices were off including lamp, computer and air conditioner. Groups were compared using one-way ANOVA. P<0.05 was considered significant. Mean values of ELF-EMF on the distance of 30 cm were 18.63, 18.44, 18.23 and 17.92 milligauss (mG) respectively (high, medium, low and ambient temperature set). ELF-EMF of high temperature set was higher than data of medium, low and ambient set in all the distances. ELF-EMF from convective air warming system is higher in condition of more close location and higher temperature. ELF-EMF within thirty centimeters exceeds 2mG recommended by Swedish TCO guideline.

Effect of extremely low frequency electromagnetic fields on growth rate and morphology of bacteria.

PubMed

Inhan-Garip, Ayse; Aksu, Burak; Akan, Zafer; Akakin, Dilek; Ozaydin, A Nilufer; San, Tangul

2011-12-01

To determine the effect of extremely low frequency (<300 Hz) electromagnetic fields (ELF-EMF) on the growth rate of Gram-positive and Gram-negative bacteria and to determine any morphological changes that might have been caused by ELF-EMF. Six bacterial strains, three Gram-negative and three Gram-positive were subjected to 50 Hz, 0.5 mT ELF-EMF for 6 h. To determine growth rate after ELF-EMF application, bacteria exposed to ELF-EMF for 3 h were collected, transferred to fresh medium and cultured without field application for another 4 h. Growth-rate was determined by optical density (OD) measurements made every hour. Morphological changes were determined with Transmission electron microscopy (TEM) for two gram-negative and two gram-positive strains collected after 3 h of field application. A decrease in growth rate with respect to control samples was observed for all strains during ELF-EMF application. The decrease in growth-rate continued when exposed bacteria were cultured without field application. Significant ultrastructural changes were observed in all bacterial strains, which were seen to resemble the alterations caused by cationic peptides. This study shows that ELF-EMF induces a decrease in growth rate and morphological changes for both Gram-negative and Gram-positive bacteria.

Compilation of 1987 Annual Reports of the Navy ELF (Extremely Low Frequency) Communications System Ecological Monitoring Program. Volume 2

DTIC Science & Technology

1988-08-01

such as those in the vicinity of the ELF antenna because they are pollinators of flowering plants , and are therefore important to the reproductive...COPY r- Compilation of 1987 Annual Reports o of the Navy ELF Communications System C4 Ecological Monitoring Program Volume 2 of 3 Volumes: TABS D -G...Security Classification) Compilation of 1987 Annual Reports of the Navy ELF Communications System Ecological Monitoring Program (Volume 2 of 3 Volumes

Strong Magnetic Field Fluctuations within Filamentary Auroral Density Cavities Interpreted as VLF Saucer Sources

NASA Technical Reports Server (NTRS)

Knudsen, D. L.; Kabirzadeh, R.; Burchill, J. K.; Pfaff, Robert F.; Wallis, D. D.; Bounds, S. R.; Clemmons, J. H.; Pincon, J.-L.

2012-01-01

The Geoelectrodynamics and Electro-Optical Detection of Electron and SuprathermalIon Currents (GEODESIC) sounding rocket encountered more than 100 filamentary densitycavities associated with enhanced plasma waves at ELF (3 kHz) and VLF (310 kHz)frequencies and at altitudes of 800990 km during an auroral substorm. These cavities weresimilar in size (20 m diameter in most cases) to so-called lower-hybrid cavities (LHCs)observed by previous sounding rockets and satellites; however, in contrast, many of theGEODESIC cavities exhibited up to tenfold enhancements in magnetic wave powerthroughout the VLF band. GEODESIC also observed enhancements of ELF and VLFelectric fields both parallel and perpendicular to the geomagnetic field B0 within cavities,though the VLF E field increases were often not as large proportionally as seen in themagnetic fields. This behavior is opposite to that predicted by previously published theoriesof LHCs based on passive scattering of externally incident auroral hiss. We argue thatthe GEODESIC cavities are active wave generation sites capable of radiating VLF wavesinto the surrounding plasma and producing VLF saucers, with energy supplied by cold,upward flowing electron beams composing the auroral return current. This interpretation issupported by the observation that the most intense waves, both inside and outside cavities,occurred in regions where energetic electron precipitation was largely inhibited orabsent altogether. We suggest that the wave-enhanced cavities encountered by GEODESICwere qualitatively different from those observed by earlier spacecraft because of thefortuitous timing of the GEODESIC launch, which placed the payload at apogee within asubstorm-related return current during its most intense phase, lasting only a few minutes.

Ray-tracing studies and path-integrated gains of ELF unducted whistler mode waves in the earth's magnetosphere

NASA Technical Reports Server (NTRS)

Huang, C. Y.; Goertz, C. K.

1983-01-01

Gyroresonance and Landau resonance interactions between unducted low-frequency whistler waves and trapped electrons in the earth's plasmasphere have been studied. Ray paths for waves launched near the plasmapause have been traced. In agreement with recent findings by Thorne et al. (1979), waves have been found which return through the equatorial zone with field-aligned wave normal angles. However, when the growth along the ray path is calculated for such waves, assuming an electron distribution function of the form E exp -n sin exp m alpha, it is found that for all the waves considered, the local growth rate becomes negative before plasmapause reflection, limiting the total gain to small values. Most waves reach zero gain before reflection. This is the result of Landau damping at oblique propagation angles, which necessarily occurs before reflection can take place. It is concluded that the concept of cyclic ray paths does not provide an explanation for the generation of unguided plasmaspheric hiss.

Extremely Low Frequency Magnetic Field (50 Hz, 0.5 mT) Reduces Oxidative Stress in the Brain of Gerbils Submitted to Global Cerebral Ischemia

PubMed Central

Rauš Balind, Snežana; Selaković, Vesna; Radenović, Lidija; Prolić, Zlatko; Janać, Branka

2014-01-01

Magnetic field as ecological factor has influence on all living beings. The aim of this study was to determine if extremely low frequency magnetic field (ELF-MF, 50 Hz, 0.5 mT) affects oxidative stress in the brain of gerbils submitted to 10-min global cerebral ischemia. After occlusion of both carotid arteries, 3-month-old gerbils were continuously exposed to ELF-MF for 7 days. Nitric oxide and superoxide anion production, superoxide dismutase activity and index of lipid peroxidation were examined in the forebrain cortex, striatum and hippocampus on the 7th (immediate effect of ELF-MF) and 14th day after reperfusion (delayed effect of ELF-MF). Ischemia per se increased oxidative stress in the brain on the 7th and 14th day after reperfusion. ELF-MF also increased oxidative stress, but to a greater extent than ischemia, only immediately after cessation of exposure. Ischemic gerbils exposed to ELF-MF had increased oxidative stress parameters on the 7th day after reperfusion, but to a lesser extent than ischemic or ELF-MF-exposed animals. On the 14th day after reperfusion, oxidative stress parameters in the brain of these gerbils were mostly at the control levels. Applied ELF-MF decreases oxidative stress induced by global cerebral ischemia and thereby reduces possible negative consequences which free radical species could have in the brain. The results presented here indicate a beneficial effect of ELF-MF (50 Hz, 0.5 mT) in the model of global cerebral ischemia. PMID:24586442

Study of extremely low frequency electromagnetic fields in infant incubators.

PubMed

Cermáková, Eleonora

2003-01-01

The aim of the work was to present the results of measurements of extremely low frequency electromagnetic fields (ELF EMF), namely the magnetic flux density, inside infant incubators, and to compare these results with the data published by other authors who point out to a possible association between leukemia or other diseases observed in newborns kept in incubators after the birth and the ELF EMF exposure in the incubator. The measured magnetic flux densities were compared with the reference values for this frequency range indicated in the European Union (EU) recommendations. The repeated measurements in incubators were made with a calibrated magnetometer EFA 300 in the frequency range of 5-30 kHz. Effective values of magnetic flux densities of ELF EMF were determined taking account of the reference values. The results of many repeated measurements showing the values of magnetic flux density in modern incubators with plastic supporting frame, were compared with those obtained in old type incubators with iron skeleton. A power frequency of 50 Hz was detected in the incubator and the ELF EMF values were by over two orders lower than the EU reference values. The paper emphasizes the need to take a special care of newborns kept in incubators even if only the sub-reference values are detected. The EU reference values are intended for the adult human population. A baby in an incubator has much smaller dimensions, higher electric conductivity and maybe trigger another mechanism of response to ELF EMF than that indicated in this paper.

An improved ELF/VLF method for globally geolocating sprite-producing lightning

NASA Astrophysics Data System (ADS)

Price, Colin; Asfur, Mustafa; Lyons, Walter; Nelson, Thomas

2002-02-01

The majority of sprites, the most common of transient luminous events (TLEs) in the upper atmosphere, are associated with a sub-class of positive cloud-to-ground lightning flashes (+CGs) whose characteristics are slowly being revealed. These +CGs produce extremely low frequency (ELF) and very low frequency (VLF) radiation detectable at great distances from the parent thunderstorm. During the STEPS field program in the United States, ELF/VLF transients associated with sprites were detected in the Negev Desert, Israel, some 11,000 km away. Within a two-hour period on 4 July 2000, all of the sprites detected optically in the United States produced detectable ELF/VLF transients in Israel. All of these transients were of positive polarity (representing positive lightning). Using the VLF data to obtain the azimuth of the transients, and the ELF data to calculate the distance between the source and receiver, we remotely determined the position of the sprite-forming lightning with an average locational error of 184 km (error of 1.6%).

Extremely Low Frequency Electromagnetic Fields impair the Cognitive and Motor Abilities of Honey Bees.

PubMed

Shepherd, S; Lima, M A P; Oliveira, E E; Sharkh, S M; Jackson, C W; Newland, P L

2018-05-21

Extremely low frequency electromagnetic field (ELF EMF) pollution from overhead powerlines is known to cause biological effects across many phyla, but these effects are poorly understood. Honey bees are important pollinators across the globe and due to their foraging flights are exposed to relatively high levels of ELF EMF in proximity to powerlines. Here we ask how acute exposure to 50 Hz ELF EMFs at levels ranging from 20-100 µT, found at ground level below powerline conductors, to 1000-7000 µT, found within 1 m of the conductors, affects honey bee olfactory learning, flight, foraging activity and feeding. ELF EMF exposure was found to reduce learning, alter flight dynamics, reduce the success of foraging flights towards food sources, and feeding. The results suggest that 50 Hz ELF EMFs emitted from powerlines may represent a prominent environmental stressor for honey bees, with the potential to impact on their cognitive and motor abilities, which could in turn reduce their ability to pollinate crops.

An entropy regularization method applied to the identification of wave distribution function for an ELF hiss event

NASA Astrophysics Data System (ADS)

Prot, Olivier; SantolíK, OndřEj; Trotignon, Jean-Gabriel; Deferaudy, Hervé

2006-06-01

An entropy regularization algorithm (ERA) has been developed to compute the wave-energy density from electromagnetic field measurements. It is based on the wave distribution function (WDF) concept. To assess its suitability and efficiency, the algorithm is applied to experimental data that has already been analyzed using other inversion techniques. The FREJA satellite data that is used consists of six spectral matrices corresponding to six time-frequency points of an ELF hiss-event spectrogram. The WDF analysis is performed on these six points and the results are compared with those obtained previously. A statistical stability analysis confirms the stability of the solutions. The WDF computation is fast and without any prespecified parameters. The regularization parameter has been chosen in accordance with the Morozov's discrepancy principle. The Generalized Cross Validation and L-curve criterions are then tentatively used to provide a fully data-driven method. However, these criterions fail to determine a suitable value of the regularization parameter. Although the entropy regularization leads to solutions that agree fairly well with those already published, some differences are observed, and these are discussed in detail. The main advantage of the ERA is to return the WDF that exhibits the largest entropy and to avoid the use of a priori models, which sometimes seem to be more accurate but without any justification.

Initial Results from SQUID Sensor: Analysis and Modeling for the ELF/VLF Atmospheric Noise.

PubMed

Hao, Huan; Wang, Huali; Chen, Liang; Wu, Jun; Qiu, Longqing; Rong, Liangliang

2017-02-14

In this paper, the amplitude probability density (APD) of the wideband extremely low frequency (ELF) and very low frequency (VLF) atmospheric noise is studied. The electromagnetic signals from the atmosphere, referred to herein as atmospheric noise, was recorded by a mobile low-temperature superconducting quantum interference device (SQUID) receiver under magnetically unshielded conditions. In order to eliminate the adverse effect brought by the geomagnetic activities and powerline, the measured field data was preprocessed to suppress the baseline wandering and harmonics by symmetric wavelet transform and least square methods firstly. Then statistical analysis was performed for the atmospheric noise on different time and frequency scales. Finally, the wideband ELF/VLF atmospheric noise was analyzed and modeled separately. Experimental results show that, Gaussian model is appropriate to depict preprocessed ELF atmospheric noise by a hole puncher operator. While for VLF atmospheric noise, symmetric α -stable (S α S) distribution is more accurate to fit the heavy-tail of the envelope probability density function (pdf).

Initial Results from SQUID Sensor: Analysis and Modeling for the ELF/VLF Atmospheric Noise

PubMed Central

Hao, Huan; Wang, Huali; Chen, Liang; Wu, Jun; Qiu, Longqing; Rong, Liangliang

2017-01-01

In this paper, the amplitude probability density (APD) of the wideband extremely low frequency (ELF) and very low frequency (VLF) atmospheric noise is studied. The electromagnetic signals from the atmosphere, referred to herein as atmospheric noise, was recorded by a mobile low-temperature superconducting quantum interference device (SQUID) receiver under magnetically unshielded conditions. In order to eliminate the adverse effect brought by the geomagnetic activities and powerline, the measured field data was preprocessed to suppress the baseline wandering and harmonics by symmetric wavelet transform and least square methods firstly. Then statistical analysis was performed for the atmospheric noise on different time and frequency scales. Finally, the wideband ELF/VLF atmospheric noise was analyzed and modeled separately. Experimental results show that, Gaussian model is appropriate to depict preprocessed ELF atmospheric noise by a hole puncher operator. While for VLF atmospheric noise, symmetric α-stable (SαS) distribution is more accurate to fit the heavy-tail of the envelope probability density function (pdf). PMID:28216590

An Investigation on the Effect of Extremely Low Frequency Pulsed Electromagnetic Fields on Human Electrocardiograms (ECGs).

PubMed

Fang, Qiang; Mahmoud, Seedahmed S; Yan, Jiayong; Li, Hui

2016-11-23

For this investigation, we studied the effects of extremely low frequency pulse electromagnetic fields (ELF-PEMF) on the human cardiac signal. Electrocardiograms (ECGs) of 22 healthy volunteers before and after a short duration of ELF-PEMF exposure were recorded. The experiment was conducted under single-blind conditions. The root mean square (RMS) value of the recorded data was considered as comparison criteria. We also measured and analysed four important ECG time intervals before and after ELF-PEMF exposure. Results revealed that the RMS value of the ECG recordings from 18 participants (81.8% of the total participants) increased with a mean value of 3.72%. The increase in ECG voltage levels was then verified by a second experimental protocol with a control exposure. In addition to this, we used hyperbolic T-distributions (HTD) in the analysis of ECG signals to verify the change in the RR interval. It was found that there were small shifts in the frequency-domain signal before and after EMF exposure. This shift has an influence on all frequency components of the ECG signals, as all spectrums were shifted. It is shown from this investigation that a short time exposure to ELF-PEMF can affect the properties of ECG signals. Further study is needed to consolidate this finding and discover more on the biological effects of ELF-PEMF on human physiological processes.

Exposure of Surgeons to Extremely Low-Frequency Magnetic Fields During Laparoscopic and Robotic Surgeries

PubMed Central

Park, Jee Soo; Chung, Jai Won; Kim, Nam Kyu; Cho, Min Soo; Kang, Chang Moo; Choi, Soo Beom; Kim, Deok Won

2015-01-01

Abstract The development of new medical electronic devices and equipment has increased the use of electrical apparatuses in surgery. Many studies have reported the association of long-term exposure to extremely low-frequency magnetic fields (ELF-MFs) with diseases or cancer. Robotic surgery has emerged as an alternative tool to overcome the disadvantages of conventional laparoscopic surgery. However, there has been no report regarding how much ELF-MF surgeons are exposed to during laparoscopic and robotic surgeries. In this observational study, we aimed to measure and compare the ELF-MFs that surgeons are exposed to during laparoscopic and robotic surgery. The intensities of the ELF-MFs surgeons are exposed to were measured every 4 seconds for 20 cases of laparoscopic surgery and 20 cases of robotic surgery using portable ELF-MF measuring devices with logging capability. The mean ELF-MF exposures were 0.6 ± 0.1 mG for laparoscopic surgeries and 0.3 ± 0.0 mG for robotic surgeries (significantly lower with P < 0.001 by Mann–Whitney U test). Our results show that the ELF-MF exposure levels of surgeons in both robotic and conventional laparoscopic surgery were lower than 2 mG, which is the most stringent level considered safe in many studies. However, we should not overlook the effects of long-term ELF-MF exposure during many surgeries in the course of a surgeon's career. PMID:25674758

A Novel Detection Method for Underwater Moving Targets by Measuring Their ELF Emissions with Inductive Sensors

PubMed Central

Li, Bin; Chen, Lianping; Li, Li

2017-01-01

In this article, we propose a novel detection method for underwater moving targets by detecting their extremely low frequency (ELF) emissions with inductive sensors. The ELF field source of the targets is modeled by a horizontal electric dipole at distances more than several times of the targets’ length. The formulas for the fields produced in air are derived with a three-layer model (air, seawater and seafloor) and are evaluated with a complementary numerical integration technique. A proof of concept measurement is presented. The ELF emissions from a surface ship were detected by inductive electronic and magnetic sensors as the ship was leaving a harbor. ELF signals are of substantial strength and have typical characteristic of harmonic line spectrum, and the fundamental frequency has a direct relationship with the ship’s speed. Due to the high sensitivity and low noise level of our sensors, it is capable of resolving weak ELF signals at long distance. In our experiment, a detection distance of 1300 m from the surface ship above the sea surface was realized, which shows that this method would be an appealing complement to the usual acoustic detection and magnetic anomaly detection capability. PMID:28788097

Effects of extremely low frequency electromagnetic fields on distortion product otoacoustic emissions in rabbits.

PubMed

Budak, Bilgehan; Budak, Gürer G; Oztürk, Göknur Güler; Muluk, Nuray Bayar; Apan, Alpaslan; Seyhan, Nesrin

2009-06-01

Humans are continuously exposed to extremely low frequency (ELF), electromagnetic fields (EMF), transmitted from the common sources like power stations, electric transmission lines, communication and radio-television signal transmission units. The present study aimed to assess the effects of 50 Hz ELF-EMF of 5.068 and 10.182 kV/m electric fields, which refer to the lower and upper intensity limits beyond which hazardous effects can be observed, on the auditory functions of rabbits via Distortion Product Otoacoustic Emission (DPOAE) recordings. The study was performed on 20 healthy adult female New Zealand White rabbits randomly divided into two groups and applied 50 Hz ELF-EMF with either 5.068 kV/m (Group 1) or 10.182 kV/m (Group 2) of electric field for 3h/day during 14 days. DPOAE responses recorded on the 0th day before exposure (B-EMF) and on the 6th (A-EMF-6th) and 14th (A-EMF-14th) days after exposure (AE). Mean stimulus intensity and emission amplitudes at 1.0-8.0 kHz were analyzed. In Group 2 rabbits, on 6th and 14th days, the DPOAE amplitudes were observed as increased at 1.5-4.0 kHz (at 2.0 and 4.0 kHz significantly) than B-EMF values. At 6.0 kHz, A-EMF-14th amplitudes were significantly lower than A-EMF values. These results suggest that ELF EMFs might affect hearing functions by frequency dependent manner. Higher ELF EMFs exposure caused increase of cochlear activity. Ototoxic effect of 10.182 kV/m ELF EMFs may begin at the basal turn of the cochlea by reducing DPOAEs at high frequencies.

Extremely Low-Frequency Electromagnetic Fields Affect Myogenic Processes in C2C12 Myoblasts: Role of Gap-Junction-Mediated Intercellular Communication

PubMed Central

Rovetta, Francesca; Boniotti, Jennifer; Mazzoleni, Giovanna

2017-01-01

Extremely low-frequency electromagnetic fields (ELF-EMFs) can interact with biological systems. Although they are successfully used as therapeutic agents in physiatrics and rehabilitative practice, they might represent environmental pollutants and pose a risk to human health. Due to the lack of evidence of their mechanism of action, the effects of ELF-EMFs on differentiation processes in skeletal muscle were investigated. C2C12 myoblasts were exposed to ELF-EMFs generated by a solenoid. The effects of ELF-EMFs on cell viability and on growth and differentiation rates were studied using colorimetric and vital dye assays, cytomorphology, and molecular analysis of MyoD and myogenin expression, respectively. The establishment of functional gap junctions was investigated analyzing connexin 43 expression levels and measuring cell permeability, using microinjection/dye-transfer assays. The ELF-EMFs did not affect C2C12 myoblast viability or proliferation rate. Conversely, at ELF-EMF intensity in the mT range, the myogenic process was accelerated, through increased expression of MyoD, myogenin, and connexin 43. The increase in gap-junction function suggests promoting cell fusion and myotube differentiation. These data provide the first evidence of the mechanism through which ELF-EMFs may provide therapeutic benefits and can resolve, at least in part, some conditions of muscle dysfunction. PMID:28607928

Schumann Resonances on Mars - a Two-layer Ground Case

NASA Astrophysics Data System (ADS)

Kozakiewicz, J.; Kulak, A.; Mlynarczyk, J.

2012-04-01

Schumann resonances (SR) are global resonances of electromagnetic waves in the range of extremely low frequencies (ELF) propagating in a cavity formed by a planetary surface and a lower ionosphere. SR are induced by electrical discharges, which on Earth are associated mainly with lightning. They were predicted by Winfried Otto Schumann in 1952. SR are supposed to occur on Mars, although many properties of the Martian environment are still unknown. One of the most important problems in modeling SR on Mars is to estimate electrical properties of the Martian ground and their influence on ELF waves propagation. The Martian crust is composed mainly of basaltic materials. Water, which causes significant increase in electrical conductivity of rocks, does not exist in liquid state at the surface of Mars. Therefore the Martian ground is believed to be a low conductive one. However, it is possible that some liquid water may be present at various depths below the surface. In our previous study we have developed an analytical model, based on the characteristic electric and magnetic altitudes' formalism, that has allowed us to take into consideration the Martian ground. Using this new model, we found that basaltic ground of low conductivity greatly influenced the SR parameters. In this work, we carried out simulations in order to characterize an influence of vertical changes in ground properties on the parameters of the Martian ground-ionosphere waveguide. We have considered several cases of a two-layer ground, in which the lower layer was of higher conductivity than the upper one. The obtained results indicate how the SR parameters depend on electrical conductivity, permittivity, and depth of the layers. The results also point out the importance of studying SR on Mars and the need for further research in propagation of ELF waves in the Martian environment. SR can be used as a remote sensing tool for exploration of the Martian crust. Furthermore, they can be especially useful for groundwater detection.

Whistler and Alfvén Mode Cyclotron Masers in Space

NASA Astrophysics Data System (ADS)

Trakhtengerts, V. Y.; Rycroft, M. J.

2012-10-01

Preface; 1. Introduction; 2. Basic theory of cyclotron masers (CMs); 3. Linear theory of the cyclotron instability (CI); 4. Backward wave oscillator (BWO) regime in CMs; 5. Nonlinear cyclotron wave-particle interactions for a quasi-monochromatic wave; 6. Nonlinear interaction of quasi-monochromatic whistler mode waves with gyroresonant electrons in an in homogeneous plasma; 7. Wavelet amplification in an inhomogeneous plasma; 8. Quasi-linear theory of cyclotron masers; 9. Nonstationary generation regimes, and modulation effects; 10. ELF/VLF noise-like emissions and electrons in the Earth's radiation belts; 11. Generation of discrete ELF/VLF whistler mode emissions; 12. Cyclotron instability of the proton radiation belts; 13. Cyclotron masers elsewhere in the solar system and in laboratory plasma devices; Epilogue; Glossary of terms; List of acronyms; References; Index.

Effects of Extremely Low Frequency Electromagnetic Fields on Vascular Permeability of Circumventricular Organs in the Adult Rat

NASA Astrophysics Data System (ADS)

Gutiérrez-Mercado, Y. K.; Cañedo-Dorantes, L.; Bañuelos-Pineda, J.; Serrano-Luna, G.; Feria-Velasco, A.

2008-08-01

The present work deals with the effects of extremely low frequency electromagnetic fields (ELF-EMF) on blood vessels permeability to non liposoluble substances of the circumventricular organs (CVO) of adult rats. Male Wistar adult rats were exposed to ELF-EMF and vascular permeability to colloidal carbon was investigated with the use of histological techniques. Results were compared to corresponding data from sham-exposed and control groups of animals. Exposure to ELF-EMF increased the CVO vascular permeability to colloidal carbon intravascularly injected, particularly in the subfornical organ, the median eminence, the pineal gland and the area postrema.

The Energy Metabolism in Caenorhabditis elegans under The Extremely Low-Frequency Electromagnetic Field Exposure

NASA Astrophysics Data System (ADS)

Shi, Zhenhua; Yu, Hui; Sun, Yongyan; Yang, Chuanjun; Lian, Huiyong; Cai, Peng

2015-02-01

A literal mountain of documentation generated in the past five decades showing unmistakable health hazards associated with extremely low-frequency electromagnetic fields (ELF-EMFs) exposure. However, the relation between energy mechanism and ELF-EMF exposure is poorly understood. In this study, Caenorhabditis elegans was exposed to 50 Hz ELF-EMF at intensities of 0.5, 1, 2, and 3 mT, respectively. Their metabolite variations were analyzed by GC-TOF/MS-based metabolomics. Although minimal metabolic variations and no regular pattern were observed, the contents of energy metabolism-related metabolites such as pyruvic acid, fumaric acid, and L-malic acid were elevated in all the treatments. The expressions of nineteen related genes that encode glycolytic enzymes were analyzed by using quantitative real-time PCR. Only genes encoding GAPDH were significantly upregulated (P < 0.01), and this result was further confirmed by western blot analysis. The enzyme activity of GAPDH was increased (P < 0.01), whereas the total intracellular ATP level was decreased. While no significant difference in lifespan, hatching rate and reproduction, worms exposed to ELF-EMF exhibited less food consumption compared with that of the control (P < 0.01). In conclusion, C. elegans exposed to ELF-EMF have enhanced energy metabolism and restricted dietary, which might contribute to the resistance against exogenous ELF-EMF stress.

Overexpression of miR-26b-5p regulates the cell cycle by targeting CCND2 in GC-2 cells under exposure to extremely low frequency electromagnetic fields.

PubMed

Liu, Yong; Liu, Wen-Bin; Liu, Kai-Jun; Ao, Lin; Cao, Jia; Zhong, Julia Li; Liu, Jin-Yi

2016-01-01

The increasing prevalence of extremely low frequency electromagnetic fields (ELF-EMFs) exposure has raised considerable public concern regarding the potential hazardous effects of ELF-EMFs on male reproductive function. Increasing evidence indicates that miRNAs are necessary for spermatogenesis and male fertility. However, the regulation of miRNA expression and the roles of miRNAs in response to ELF-EMFs remain unclear. In our study, mouse spermatocyte-derived GC-2 cells were intermittently exposed to a 50 Hz ELF-EMF for 72 h (5 min on/10 min off) at magnetic field intensities of 1 mT, 2 mT and 3 mT. MiR-26b-5p was differentially expressed in response to different magnetic field intensities of ELF-EMFs. The host gene CTDSP1 showed an unmethylation status in GC-2 cells at different magnetic field intensities of ELF-EMF exposure. MiR-26b-5p had no significant, obvious influence on the cell viability, apoptosis or cell cycle of GC-2 cells. However, the overexpression of miR-26b-5p significantly decreased the percentage of G0/G1 phase cells and slightly increased the percentage of S phase cells compared to the sham group that was exposed to a 50 Hz ELF-EMF. Computational algorithms identified Cyclin D2 (CCND2) as a direct target of miR-26b-5p. MiR-26b-5p and a 50 Hz ELF-EMF altered the expression of CCND2 at both the mRNA and protein levels. Overexpressed miR-26b-5p in GC-2 cells can change the mRNA expression of CCND2 following 50 Hz ELF-EMF at 3 mT. These findings demonstrate that miR-26b-5p could serve as a potential biomarker following 50 Hz ELF-EMF exposure, and miR-26b-5p-CCND2-mediated cell cycle regulation might play a pivotal role in the biological effects of ELF-EMFs.

The Impact of the Type 094 Ballistic Missile Submarine on China’s Nuclear Policy

DTIC Science & Technology

2009-06-01

74 Figure 9. VLF Towers at Greenbury Point in Annapolis, MD........................................75 Figure 10. ELF Communications Source...China’s ability to utilize these systems. Extremely low frequency ( ELF ) communications have the advantage that messages can be received at depths of...capabilities. Even with this increase, it will still be difficult for China to maintain constant two-way communications with ELF or VLF in high sea

Wisconsin Test Facility Ground Terminal Corrosion Study.

DTIC Science & Technology

1978-04-01

The technical effort reported herein is intended to support development of the Navy’s ELF Submarine Command and Control Communications System. The... ELF Extremely Low Frequency Ground System Corros ion Investigations of ELF ground system corrosion at the Navy’s Wisconsin Te’st Facility were...the Special Communications Project Office of the U. S. Naval Electronic Systems Command by lIT Research Institute, as part of Contract N00039-76-C-0141

Ultrastructural Study on Ultra-Low Frequency Electromagnetic Fields and Transfer Factor Effects on Skin Ulcers

NASA Astrophysics Data System (ADS)

Cadena, M. S. Reyes; Chapul, L. Sánchez; Pérez, Javiér; García, M. N. Jiménez; López, M. A. Jiménez; Espíndola, M. E. Sánchez; Perez, R. Paniagua; Hernández, N. A.; Paniagua, G.; Uribe, F.; Nava, J. J. Godina; Segura, M. A. Rodríguez

2008-08-01

We determined the effect of 120Hz ultra low frequency electromagnetic field (ELF) on the healing process of skin in 20 Wistar rats distributed in four groups in which chronic dermal ulcers had been produced. The first two groups received a dose of the transfer factor and interferon-beta (IFN-β) every 24 h during 12 days. The third group (positive control) received only electromagnetic field (ELF) sessions, and in the fourth group (negative control), no treatment was applied. The electromagnetic field was applied through a Helmholtz coils; 30 Gauss of intensity. Results shown histological changes that improve the healing process in animals subjected to ELF together with the transfer factor.

Occupational exposure to extremely low frequency magnetic fields and brain tumour risks in the INTEROCC study

PubMed Central

Turner, Michelle C; Benke, Geza; Bowman, Joseph D; Figuerola, Jordi; Fleming, Sarah; Hours, Martine; Kincl, Laurel; Krewski, Daniel; McLean, Dave; Parent, Marie-Elise; Richardson, Lesley; Sadetzki, Siegal; Schlaefer, Klaus; Schlehofer, Brigitte; Schüz, Joachim; Siemiatycki, Jack; van Tongeren, Martie; Cardis, Elisabeth

2014-01-01

Background Occupational exposure to extremely low frequency magnetic fields (ELF) is a suspected risk factor for brain tumours, however the literature is inconsistent. Few studies have assessed whether ELF in different time windows of exposure may be associated with specific histologic types of brain tumours. This study examines the association between ELF and brain tumours in the large-scale INTEROCC study. Methods Cases of adult primary glioma and meningioma were recruited in seven countries (Australia, Canada, France, Germany, Israel, New Zealand, United Kingdom) between 2000 and 2004. Estimates of mean workday ELF exposure based on a job exposure matrix assigned. Estimates of cumulative exposure, average exposure, maximum exposure, and exposure duration were calculated for the lifetime, and 1–4, 5–9, and 10+ years prior to the diagnosis/reference date. Results There were 3,761 included brain tumour cases (1,939 glioma, 1,822 meningioma) and 5,404 population controls. There was no association between lifetime cumulative ELF exposure and glioma or meningioma risk. However, there were positive associations between cumulative ELF 1–4 years prior to the diagnosis/reference date and glioma (odds ratio (OR) ≥ 90th percentile vs < 25th percentile = 1.67, 95% confidence interval (CI) 1.36–2.07, p < 0.0001 linear trend), and, somewhat weaker associations with meningioma (OR ≥ 90th percentile vs < 25th percentile = 1.23, 95% CI 0.97–1.57, p = 0.02 linear trend). Conclusions Results showed positive associations between ELF in the recent past and glioma. Impact Occupational ELF exposure may play a role in the later stages (promotion and progression) of brain tumourigenesis. PMID:24935666

Short-term effects of extremely low-frequency pulsed electromagnetic field and pulsed low-level laser therapy on rabbit model of corneal alkali burn.

PubMed

Rezaei Kanavi, Mozhgan; Tabeie, Faraj; Sahebjam, Farzin; Poursani, Nima; Jahanbakhsh, Nazanin; Paymanpour, Pouya; AfsarAski, Sasha

2016-04-01

This study was conducted to investigate the effect of combining extremely low frequency-pulsed electromagnetic field (ELF-PEMF) and low-level laser therapy (LLLT) on alkali-burned rabbit corneas. Fifty alkali-burned corneas of 50 rabbits were categorized into five groups: ELF-PEMF therapy with 2 mT intensity (ELF 2) for 2 h daily; LLLT for 30 min twice daily; combined ELF-PEMF and LLLT (ELF + LLLT); medical therapy (MT); and control (i.e., no treatment). Clinical examination and digital photography of the corneas were performed on days 0, 2, 7, and 14. After euthanizing the rabbits, the affected eyes were evaluated by histopathology. The clinical and histopathologic results were compared between the groups. On days 7 and 14, no significant difference in the corneal defect area was evident between the ELF, LLLT, ELF + LLLT, and MT groups. Excluding the controls, none of the study groups demonstrated a significant corneal neovascularization in both routine histopathology and immunohistochemistry for CD31. Keratocyte loss was significantly higher in the MT group than in the ELF, LLLT, and ELF + LLLT groups. Moderate to severe stromal inflammation in the LLLT group was comparable with that in the MT group and was significantly lower than that in the other groups. In conclusion, combining LLLT and ELF was not superior to ELF alone or LLLT alone in healing corneal alkali burns. However, given the lower intensity of corneal inflammation and the lower rate of keratocytes loss with LLLT, this treatment may be superior to other proposed treatment modalities for healing alkali-burned corneas. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of extremely low frequency magnetic field on oxidative balance in brain of rats.

PubMed

Ciejka, Elzbieta; Kleniewska, P; Skibska, B; Goraca, A

2011-12-01

Extremely low frequency magnetic field (ELF-MF) may result in oxidative DNA damage and lipid peroxidation with an ultimate effect on a number of systemic disturbances and cell death. The aim of the study is to assess the effect of ELF-MF parameters most frequently used in magnetotherapy on reactive oxygen species generation (ROS) in brain tissue of experimental animals depending on the time of exposure to this field. The research material included adult male Sprague-Dawley rats, aged 3-4 months. The animals were divided into 3 groups: I - control (shame) group; II - exposed to the following parameters of the magnetic field: 7 mT, 40 Hz, 30 min/day, 10 days; III - exposed to the ELF-MF parameters of 7 mT, 40 Hz, 60 min/day, 10 days. The selected parameters of oxidative stress: thiobarbituric acid reactive substances (TBARS), hydrogen peroxide (H(2)O(2)), total free sulphydryl groups (-SH groups) and protein in brain homogenates were measured after the exposure of rats to the magnetic field. ELF-MF parameters of 7 mT, 40 Hz, 30 min/day for 10 days caused a significant increase in lipid peroxidation and insignificant increase in H(2)O(2) and free -SH groups. The same ELF-MF parameters but applied for 60 min/day caused a significant increase in free -SH groups and protein concentration in the brain homogenates indicating the adaptive mechanism. The study has shown that ELF-MF applied for 30 min/day for 10 days can affect free radical generation in the brain. Prolongation of the exposure to ELF-MF (60/min/day) caused adaptation to this field. The effect of ELF-MF irradiation on oxidative stress parameters depends on the time of animal exposure to magnetic field.

The impact of background radiation, illumination and temperature on EMF-induced changes of aqua medium properties.

PubMed

Naira, Baghdasaryan; Yerazik, Mikayelyan; Anna, Nikoghosyan; Sinerik, Ayrapetyan

2013-09-01

The effects of extremely low frequency electromagnetic field (ELF EMF) on physicochemical properties of physiological solution at different environmental media were studied. The existence of frequency "windows" at 4 and 8 Hz frequencies of ELF EMF having effects on heat fusion period, hydrogen peroxide (H2O2) formation and oxygen (O2) content of water solution and different dependency on temperature, background radiation and illumination was shown. Obtained data allow us to suggest that EMF-induced effect on water physicochemical properties depends on abovementioned environmental factors. As cell bathing medium is a target for biological effects of ELF EMF, the variability of experimental data on biological effects of EMF, obtained in different laboratories, can be explained by different environmental conditions of experiments, which very often are not considered adequately.

Compilation of 1986 Annual Reports of the Navy ELF (Extremely Low Frequency) Communications System Ecological Monitoring Program. Volume 2. TABS D-G.

DTIC Science & Technology

1987-07-01

8217. -. , i U ELF ECOLOGICAL MONITORING PROGRAM INDEX OF 1986 ANNUAL REPORTS A. Herbaceous Plant Cover and Tree Studies \\ Michigan Technological University...SUBCONTRACT NUMBER EO 6549-84-C-005 LELF Communications System Ecological Monitoring Program BIOLOGICAL STUDIES ON POLLINATING INSECTS: MEGACHILID...such as those in the vicinity of the ELF antenna because they are pollinators of flowering plants , and are therefore important to the reproductive

Neuritin reverses deficits in murine novel object associative recognition memory caused by exposure to extremely low-frequency (50 Hz) electromagnetic fields

PubMed Central

Zhao, Qian-Ru; Lu, Jun-Mei; Yao, Jin-Jing; Zhang, Zheng-Yu; Ling, Chen; Mei, Yan-Ai

2015-01-01

Animal studies have shown that electromagnetic field exposure may interfere with the activity of brain cells, thereby generating behavioral and cognitive disturbances. However, the underlying mechanisms and possible preventions are still unknown. In this study, we used a mouse model to examine the effects of exposure to extremely low-frequency (50 Hz) electromagnetic fields (ELF MFs) on a recognition memory task and morphological changes of hippocampal neurons. The data showed that ELF MFs exposure (1 mT, 12 h/day) induced a time-dependent deficit in novel object associative recognition memory and also decreased hippocampal dendritic spine density. This effect was observed without corresponding changes in spontaneous locomotor activity and was transient, which has only been seen after exposing mice to ELF MFs for 7-10 days. The over-expression of hippocampal neuritin, an activity-dependent neurotrophic factor, using an adeno-associated virus (AAV) vector significantly increased the neuritin level and dendritic spine density. This increase was paralleled with ELF MFs exposure-induced deficits in recognition memory and reductions of dendritic spine density. Collectively, our study provides evidence for the association between ELF MFs exposure, impairment of recognition memory, and resulting changes in hippocampal dendritic spine density. Neuritin prevented this ELF MFs-exposure-induced effect by increasing the hippocampal spine density. PMID:26138388

Neuritin reverses deficits in murine novel object associative recognition memory caused by exposure to extremely low-frequency (50 Hz) electromagnetic fields.

PubMed

Zhao, Qian-Ru; Lu, Jun-Mei; Yao, Jin-Jing; Zhang, Zheng-Yu; Ling, Chen; Mei, Yan-Ai

2015-07-03

Animal studies have shown that electromagnetic field exposure may interfere with the activity of brain cells, thereby generating behavioral and cognitive disturbances. However, the underlying mechanisms and possible preventions are still unknown. In this study, we used a mouse model to examine the effects of exposure to extremely low-frequency (50 Hz) electromagnetic fields (ELF MFs) on a recognition memory task and morphological changes of hippocampal neurons. The data showed that ELF MFs exposure (1 mT, 12 h/day) induced a time-dependent deficit in novel object associative recognition memory and also decreased hippocampal dendritic spine density. This effect was observed without corresponding changes in spontaneous locomotor activity and was transient, which has only been seen after exposing mice to ELF MFs for 7-10 days. The over-expression of hippocampal neuritin, an activity-dependent neurotrophic factor, using an adeno-associated virus (AAV) vector significantly increased the neuritin level and dendritic spine density. This increase was paralleled with ELF MFs exposure-induced deficits in recognition memory and reductions of dendritic spine density. Collectively, our study provides evidence for the association between ELF MFs exposure, impairment of recognition memory, and resulting changes in hippocampal dendritic spine density. Neuritin prevented this ELF MFs-exposure-induced effect by increasing the hippocampal spine density.

Observations of 50/60 Hz Power Line Radiation in the Low Latitude Ionosphere Detected by the Electric Field Instrument on the C/NOFS Satellite

NASA Astrophysics Data System (ADS)

Pfaff, R. F., Jr.; Freudenreich, H. T.; Simoes, F. A.; Liebrecht, M. C.; Farrell, W.

2017-12-01

One of the most ubiquitous forms of EM radiation emanating from the earth's surface is that of power line radiation. Associated with AC electric power generation, such emissions are typically launched along conducting power lines that may travel hundreds, or even thousands of km, from generating stations. The fundamental frequencies of such emissions are characteristically 50 Hz or 60 Hz, depending on the regional standards for power generation/consumption. The frequency of this radiation is well below that of the plasma frequency of the ionosphere (typically several MHz) and hence is expected to reflect back to the earth and propagate in the waveguide formed by the earth's surface and the bottom ledge of the ionosphere, typically near 100 km. Given that such power lines are widespread on the exposed lithosphere, the leakage of some ELF emissions associated with electric power generation might nevertheless be expected in the ionosphere, in the same manner in which a small fraction of the power associated with ELF Schumann resonances and lightning sferics have been shown to penetrate into the ionosphere. We present direct measurements of 50/60 Hz power line radiation detected by in situ probes on an orbiting satellite in the earth's ionosphere. The data were gathered by the Vector Electric Field Investigation (VEFI) tri-axial double probe detector flown on the Communication/Navigation Outage Forecast System (C/NOFS) satellite. C/NOFS was launched in April, 2008 into a low latitude (13 deg inclination) orbit with perigee and apogee of 400 km and 850 km, respectively. The electric field wave data were gathered by ELF receivers comprised of two orthogonal broadband channels sampled at 512 s/sec each, and digitized with 16 bit A/D converters. The data show distinct 60 Hz emissions while the satellite sampled within the Brazilian sector whereas distinct 50 Hz emissions were detected over India. Other, less distinct, emissions were observed over Africa and southeast Asia. We discuss the characteristics of the received emissions, including their amplitudes and spectral features (i.e., harmonics). We use these observations to advance our understanding of how natural terrestrial ELF emissions, such as those associated with Schumann resonances and lightning, penetrate into the ionosphere.

ELF-MF Occupational Exposure in Die-casting and Electroplating Workers in Korea.

PubMed

Rajitha Kawshalya, Mailan Arachchige Don; Jung, Joon-Sig; Lee, Yun-Jin; Hong, Seung-Cheol

2018-04-26

A 24-h exposure assessment was performed in two groups of blue-collar workers from a die-casting and an electroplating plant to investigate levels of exposure to extremely low-frequency magnetic fields (ELF-MF), using EMDEX Lite. ELF-MF exposure of workers from the die-casting plant AM±SD (AM=arithmetic mean, SD=standard deviation) (0.649±1.343µT)] is higher than in electroplating workers (0.138±0.045µT). Higher ELF-MF exposure was found among workers living in same building as their workplace compared to that among other workers. This study suggests that ELF-MF exposure levels should be taken into consideration when providing dormitories for workers to minimize the levels of residential ELF-MF exposure due to emission from plants. The study recommends that blue-collar workers should be made aware of measures to minimize their exposure to environmental agents such as ELF-MF and electromagnetic field (EMF) during work, such as maintaining a safe distance between machines and avoiding undesirable behavior with equipment.

Initial Results from Awesome VLF Receiver Installed in Ecuador

NASA Astrophysics Data System (ADS)

Lopez, Ericson

2012-07-01

In this work we present the first results that we have derived from analysis of data obtained using the Atmospheric Weather Electromagnetic System for Observation Modeling and Education (Awesome) VLF receiver, designed and developed by Stanford University, USA. The receiver was installed under inter-institutional cooperation in the emerging Space Science division of the Quito Astronomical Observatory, and it is working properly since 2010. We have describe the performance characteristic of the Awesome system and the importance of having receivers at equator for monitoring the ionosphere and magnetosphere, recepting extremely low frequencies (ELF;30-3000 Hz) and very low frequencies (VLF; 3-30 KHz) electromagnetic waves, in order to better understanding the physical processes which take place in these media.

Vlf/elf radiation patterns of arbitrarily oriented electric and magnetic dipoles in a cold lossless multicomponent magnetoplasma.

NASA Technical Reports Server (NTRS)

Wang, T. N. C.; Bell, T. F.

1972-01-01

With the use of a power integral formulation, a study is made of the vlf/elf radiation patterns of arbitrarily oriented electric and magnetic dipoles in a cold lossless multicomponent magnetoplasma. Expressions for the ray patterns are initially developed that apply for arbitrary values of driving frequency, static magnetic-field strength, plasma density, and composition. These expressions are subsequently specialized to vlf/elf radiation in a plasma modeled on the magnetosphere. A series of representative pattern plots are presented for frequencies between the proton and electron gyrofrequencies. These patterns illustrate the fact that focusing effects that arise from the geometrical properties of the refractive index surface tend to dominate the radiation distribution over the entire range from the electron gyrofrequency to 4.6 times the proton gyrofrequency. It is concluded that focusing effects should be of significant importance in the design of a vlf/elf satellite transmitting system in the magnetosphere.

ELF (Extremely Low Frequency) Communications Systems Ecological Monitoring Program: Wetland Studies

DTIC Science & Technology

1989-11-01

energized, or a fully operational, transmitting facility had no measurable effect on peatland plant species. I I I I UNCLASSIFIED SECURITY...field studies (1983-1987) designed to examine potential extremely low frequency (ELF) I electromagnetic field effects on peatland ecosystems in... peatlands within 0.05 km of the antenna system. The INTERMEDIATE sites (Bog’s 3 2,7,11) are located between the antenna arms and had lower

Ultrastructural Study on Ultra-Low Frequency Electromagnetic Fields and Transfer Factor Effects on Skin Ulcers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cadena, M. S. Reyes; Chapul, L. Sanchez; Perez, Javier

2008-08-11

We determined the effect of 120Hz ultra low frequency electromagnetic field (ELF) on the healing process of skin in 20 Wistar rats distributed in four groups in which chronic dermal ulcers had been produced. The first two groups received a dose of the transfer factor and interferon-beta (IFN-{beta}) every 24 h during 12 days. The third group (positive control) received only electromagnetic field (ELF) sessions, and in the fourth group (negative control), no treatment was applied. The electromagnetic field was applied through a Helmholtz coils; 30 Gauss of intensity. Results shown histological changes that improve the healing process in animalsmore » subjected to ELF together with the transfer factor.« less

ELF propagation in the presence of nonstratified ionospheric disturbances

NASA Astrophysics Data System (ADS)

Field, E. C., Jr.; Gayer, S. J.; Dambrosio, B. P.

1980-06-01

This report analyzes the propagation of the TEM-ELF waveguide mode when the ionosphere is not stratified. It treats strong localized ionospheric disturbances by recasting the lateral wave equation as a two dimensional integral equation, and applies a specially developed algorithm to obtain numerical solutions. The quasi-full wave results show that a localized ionospheric disturbance behaves like a converging cylindrical lens filling a narrow aperture. Lateral diffraction and focusing, ignored in treatments that do not fully account for transverse ionospheric structure, cause the ELF signal to exhibit a pattern of maxima and minima on the line normal to the path passing through the center of the disturbance. As expected, the focusing/diffraction effects diminish when the transverse dimension of the disturbance exceeds the width of the first Fresnel zone - typically, several megameters. The analysis models widespread inhomogeneities, such as within the polar cap or at the day/night terminator, as semiinfinite regions separated by diffuse boundaries; it then derives full-wave analytic expressions for the reflection of the TEM mode. Mode reflection is found to significantly affect an ELF signal in two actual situations: first, when receivers are on great circle paths that are nearly tangential to the disturbed polar cap - in which case shadow zones and interference patterns can occur; and second, when signals are incident on the day/night terminator (from the day side) at angles exceeding about 75 deg - in which case the signals are affected by a phenomenon analogous to total internal reflection. Reflection is found to be unimportant if the boundary thickness exceeds about one-sixth of a wavelength.

The role of localised Ultra-Low Frequency waves in energetic electron precipitation

NASA Astrophysics Data System (ADS)

Rae, J.; Murphy, K. R.; Watt, C.; Mann, I. R.; Ozeke, L.; Halford, A. J.; Sibeck, D. G.; Clilverd, M. A.; Rodger, C. J.; Degeling, A. W.; Singer, H. J.

2016-12-01

Electromagnetic waves play pivotal roles in radiation belt dynamics through a variety of different means. Typically, Ultra-Low Frequency (ULF) waves have historically been invoked for radial diffusive transport leading to both acceleration and loss of outer radiation belt electrons. Very-Low Frequency (VLF) and Extremely-Low Frequency (ELF) waves are generally thought to provide a mechanism for localized acceleration and loss through precipitation into the ionosphere. In this study we present a new mechanism for electron loss through precipitation into the ionosphere due to direct modulation of the loss cone via localized compressional ULF waves. Observational evidence is presented demonstrating that modulation of the equatorial loss cone can occur via localized compressional wave activity. We then perform statistical computations of the probability distribution to determine how likely a given magnetic perturbation would produce a given percentage change in the bounce loss-cone (BLC). We discuss the ramifications of the action of coherent, localized compressional ULF waves on drifting electron populations; their precipitation response can be a complex interplay between electron energy, the shape of the phase space density profile at pitch angles close to the loss cone, ionospheric decay timescales, and the time-dependence of the electron source. We present a case study of compressional wave activity in tandem with riometer and balloon-borne electron precipitation across keV-MeV energies to demonstrate that the experimental measurements can be explained by our new enhanced loss cone mechanism. We determine that the two pivotal components not usually considered are localized ULF wave fields and ionospheric decay timescales. We conclude that ULF wave modulation of the loss cone is a viable candidate for direct precipitation of radiation belt electrons without any additional requirement for gyroresonant wave-particle interaction. Additional mechanisms would be complementary and additive in providing means to precipitate electrons from the radiation belts during storm-times.

Power-Stepped HF Cross-Modulation Experiments: Simulations and Experimental Observations

NASA Astrophysics Data System (ADS)

Greene, S.; Moore, R. C.

2014-12-01

High frequency (HF) cross modulation experiments are a well established means for probing the HF-modified characteristics of the D-region ionosphere. The interaction between the heating wave and the probing pulse depends on the ambient and modified conditions of the D-region ionosphere. Cross-modulation observations are employed as a measure of the HF-modified refractive index. We employ an optimized version of Fejer's method that we developed during previous experiments. Experiments were performed in March 2013 at the High Frequency Active Auroral Research Program (HAARP) observatory in Gakona, Alaska. During these experiments, the power of the HF heating signal incrementally increased in order to determine the dependence of cross-modulation on HF power. We found that a simple power law relationship does not hold at high power levels, similar to previous ELF/VLF wave generation experiments. In this paper, we critically compare these experimental observations with the predictions of a numerical ionospheric HF heating model and demonstrate close agreement.

Compilation of 1986 annual reports of the Navy ELF (Extremely Low Frequency) communications system ecological monitoring program, volume 2

NASA Astrophysics Data System (ADS)

1987-07-01

The U.S. Navy is conducting a long-term program to monitor for possible effects from the operation of its Extremely Low Frequency (ELF) Communications System to resident biota and their ecological relationships. This report documents progress of the following studies: soil amoeba; soil and litter arthropoda and earthworm studies; biological studies on pollinating insects: megachilid bees; and small vertebrates: small mammals and nesting birds.

ELF-MF exposure affects the robustness of epigenetic programming during granulopoiesis

NASA Astrophysics Data System (ADS)

Manser, Melissa; Sater, Mohamad R. Abdul; Schmid, Christoph D.; Noreen, Faiza; Murbach, Manuel; Kuster, Niels; Schuermann, David; Schär, Primo

2017-03-01

Extremely-low-frequency magnetic fields (ELF-MF) have been classified as “possibly carcinogenic” to humans on the grounds of an epidemiological association of ELF-MF exposure with an increased risk of childhood leukaemia. Yet, underlying mechanisms have remained obscure. Genome instability seems an unlikely reason as the energy transmitted by ELF-MF is too low to damage DNA and induce cancer-promoting mutations. ELF-MF, however, may perturb the epigenetic code of genomes, which is well-known to be sensitive to environmental conditions and generally deranged in cancers, including leukaemia. We examined the potential of ELF-MF to influence key epigenetic modifications in leukaemic Jurkat cells and in human CD34+ haematopoietic stem cells undergoing in vitro differentiation into the neutrophilic lineage. During granulopoiesis, sensitive genome-wide profiling of multiple replicate experiments did not reveal any statistically significant, ELF-MF-dependent alterations in the patterns of active (H3K4me2) and repressive (H3K27me3) histone marks nor in DNA methylation. However, ELF-MF exposure showed consistent effects on the reproducibility of these histone and DNA modification profiles (replicate variability), which appear to be of a stochastic nature but show preferences for the genomic context. The data indicate that ELF-MF exposure stabilizes active chromatin, particularly during the transition from a repressive to an active state during cell differentiation.

ELF/VLF/LF Propagation and System Design

DTIC Science & Technology

1987-06-23

Inhorogeiieouis Pat., Up to this po’int we have discussed prediction metthods for hu.mogeneou! paths ni. Hlowever. Inc earth’s surface, earth’s...34 Scientific and Engineering Studies: Extremely Low Frequency (ELF) Pro- pagation," Naval Underwater Systems Center, Newport Laboratory, Newport, RI. 71 R.A

Different responses of Drosophila subobscura isofemale lines to extremely low frequency magnetic field (50 Hz, 0.5 mT): fitness components and locomotor activity.

PubMed

Zmejkoski, Danica; Petković, Branka; Pavković-Lučić, Sofija; Prolić, Zlatko; Anđelković, Marko; Savić, Tatjana

2017-05-01

Extremely low frequency (ELF) magnetic fields as essential ecological factors may induce specific responses in genetically different lines. The object of this study was to investigate the impact of the ELF magnetic field on fitness components and locomotor activity of five Drosophila subobscura isofemale (IF) lines. Each D. subobscura IF line, arbitrarily named: B16/1, B24/4, B39/1, B57/2 and B69/5, was maintained in five full-sib inbreeding generations. Their genetic structures were defined based on the mitochondrial DNA variability. Egg-first instar larvae and 1-day-old flies were exposed to an ELF magnetic field (50 Hz, 0.5 mT, 48 h) and thereafter, fitness components and locomotor activity of males and females in an open field test were observed for each selected IF line, respectively. Exposure of egg-first instar larvae to an ELF magnetic field shortened developmental time, and did not affect the viability and sex ratio of D. subobscura IF lines. Exposure of 1-day-old males and females IF lines B16/1 and B24/4 to an ELF magnetic field significantly decreased their locomotor activity and this effect lasted longer in females than males. These results indicate various responses of D. subobscura IF lines to the applied ELF magnetic field depending on their genetic background.

Fifty hertz extremely low-frequency magnetic field exposure elicits redox and trophic response in rat-cortical neurons.

PubMed

Di Loreto, Silvia; Falone, Stefano; Caracciolo, Valentina; Sebastiani, Pierluigi; D'Alessandro, Antonella; Mirabilio, Alessandro; Zimmitti, Vincenzo; Amicarelli, Fernanda

2009-05-01

Large research activity has raised around the mechanisms of interaction between extremely low-frequency magnetic fields (ELF-MFs) and biological systems. ELF-MFs may interfere with chemical reactions involving reactive oxygen species (ROS), thus facilitating oxidative damages in living cells. Cortical neurons are particularly susceptible to oxidative stressors and are also highly dependent on the specific factors and proteins governing neuronal development, activity and survival. The aim of the present work was to investigate the effects of exposures to two different 50 Hz sinusoidal ELF-MFs intensities (0.1 and 1 mT) in maturing rat cortical neurons' major anti-oxidative enzymatic and non-enzymatic cellular protection systems, membrane peroxidative damage, as well as growth factor, and cytokine expression pattern. Briefly, our results showed that ELF-MFs affected positively the cell viability and concomitantly reduced the levels of apoptotic death in rat neuronal primary cultures, with no significant effects on the main anti-oxidative defences. Interestingly, linear regression analysis suggested a positive correlation between reduced glutathione (GSH) and ROS levels in 1 mT MF-exposed cells. On this basis, our hypothesis is that GSH could play an important role in the antioxidant defence towards the ELF-MF-induced redox challenge. Moreover, the GSH-based cellular response was achieved together with a brain-derived neurotrophic factor over-expression as well as with the interleukin 1beta-dependent regulation of pro-survival signaling pathways after ELF-MF exposure.

Cancer incidence among welders: possible effects of exposure to extremely low frequency electromagnetic radiation (ELF) and to welding fumes.

PubMed Central

Stern, R M

1987-01-01

Epidemiological studies of cancer incidence among welders disclose a pooled total of 146 cases of leukemia observed versus 159.46 expected, a risk ratio of 0.92, and 40 cases of acute leukemia observed versus 43.39 expected, a risk ratio of 0.92. For respiratory tract cancer, the pooled total is 1789 cases observed versus 1290.7 expected, a risk ratio of 1.39. Most electric welders are exposed to extremely low frequency electromagnetic radiation (ELF) (magnetic flux densities of up to 100,000 microT), a suspected leukemogen, and to concentrated metallic aerosols (up to 200 mg/m3), which can contain the putative respiratory tract carcinogens Cr(VI) and Ni. The two exposures are usually coincident, since welding with an electric current produces welding fumes. The observation of an excess risk for respiratory tract cancer strongly suggests significant exposure both to fumes and to ELF. The absence of increased risk for all leukemia or for acute leukemia among ELF-exposed welders does not support the hypothesis that the observed excess risk for leukemia or acute leukemia among workers in the electrical trades is due to their ELF exposure, which on the average is lower than that of welders. PMID:3447902

The effects of extremely low-frequency magnetic fields on melatonin and cortisol, two marker rhythms of the circadian system

PubMed Central

Touitou, Yvan; Selmaoui, Brahim

2012-01-01

In the past 30 years the concern that daily exposure to extremely low-frequency magnetic fields (ELF-EMF) (1 to 300 Hz) might be harmful to human health (cancer, neurobehavioral disturbances, etc) has been the object of debate, and has become a public health concern. This has resulted in the classification of ELF-EMF into category 2B, ie, agents that are “possibly carcinogenic to humans” by the International Agency for Research on Cancer. Since melatonin, a neurohormone secreted by the pineal gland, has been shown to possess oncostatic properties, a “melatonin hypothesis” has been raised, stating that exposure to EMF might decrease melatonin production and therefore might promote the development of breast cancer in humans. Data from the literature reviewed here are contradictory. In addition, we have demonstrated a lack of effect of ELF-EMF on melatonin secretion in humans exposed to EMF (up to 20 years' exposure) which rebuts the melatonin hypothesis. Currently, the debate concerns the effects of ELF-EMF on the risk of childhood leukemia in children chronically exposed to more than 0.4 μT. Further research is thus needed to obtain more definite answers regarding the potential deleterious effects of ELF-EMF. PMID:23393415

Chronic exposure to ELF fields may induce depression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilson, B.W.

Exposure to extremely-low-frequency (ELF) electric or magnetic fields has been postulated as a potentially contributing factor in depression. Epidemiologic studies have yielded positive correlations between magnetic- and/or electric-field strengths in local environments and the incidence of depression-related suicide. Chronic exposure to ELF electric or magnetic fields can disrupt normal circadian rhythms in rat pineal serotonin-N-acetyltransferase activity as well as in serotonin and melatonin concentrations. Such disruptions in the circadian rhythmicity of pineal melatonin secretion have been associated with certain depressive disorders in human beings. In the rat, ELF fields may interfere with tonic aspects of neuronal input to the pinealmore » gland, giving rise to what may be termed functional pinealectomy. If long-term exposure to ELF fields causes pineal dysfunction in human beings as it does in the rat, such dysfunction may contribute to the onset of depression or may exacerbate existing depressive disorders. 85 references.« less

Effects of Electromagnetic Fields on Osteogenesis of Human Alveolar Bone-Derived Mesenchymal Stem Cells

PubMed Central

Lim, KiTaek; Hexiu, Jin; Kim, Jangho; Seonwoo, Hoon; Cho, Woo Jae; Choung, Pill-Hoon; Chung, Jong Hoon

2013-01-01

This study was performed to investigate the effects of extremely low frequency pulsed electromagnetic fields (ELF-PEMFs) on the proliferation and differentiation of human alveolar bone-derived mesenchymal stem cells (hABMSCs). Osteogenesis is a complex series of events involving the differentiation of mesenchymal stem cells to generate new bone. In this study, we examined not merely the effect of ELF-PEMFs on cell proliferation, alkaline phosphatase (ALP) activity, and mineralization of the extracellular matrix but vinculin, vimentin, and calmodulin (CaM) expressions in hABMSCs during osteogenic differentiation. Exposure of hABMSCs to ELF-PEMFs increased proliferation by 15% compared to untreated cells at day 5. In addition, exposure to ELF-PEMFs significantly increased ALP expression during the early stages of osteogenesis and substantially enhanced mineralization near the midpoint of osteogenesis within 2 weeks. ELF-PEMFs also increased vinculin, vimentin, and CaM expressions, compared to control. In particular, CaM indicated that ELF-PEMFs significantly altered the expression of osteogenesis-related genes. The results indicated that ELF-PEMFs could enhance early cell proliferation in hABMSCs-mediated osteogenesis and accelerate the osteogenesis. PMID:23862141

Analysis of impulse signals with Hylaty ELF station

NASA Astrophysics Data System (ADS)

Kulak, A.; Mlynarczyk, J.; Ostrowski, M.; Kubisz, J.; Michalec, A.

2012-04-01

Lighting discharges generate electromagnetic field pulses that propagate in the Earth-ionosphere waveguide. The attenuation in the ELF range is so small that the pulses originating from strong atmospheric discharges can be observed even several thousand kilometers away from the individual discharge. The recorded waveform depends on the discharge process, the Earth-ionosphere waveguide properties on the source-receiver path, and the transfer function of the receiver. If the distance from the source is known, an inverse method can be used for reconstructing the current moment waveform and the charge moment of the discharge. In order to reconstruct the source parameters from the recorded signal a reliable model of the radio wave propagation in the Earth-ionosphere waveguide as well as practical signal processing techniques are necessary. We present two methods, both based on analytical formulas. The first method allows for fast calculation of the charge moment of relatively short atmospheric discharges. It is based on peak amplitude measurement of the recorded magnetic component of the ELF EM field and it takes into account the receiver characteristics. The second method, called "inverse channel method" allows reconstructing the complete current moment waveform of strong atmospheric discharges that exhibit the continuing current phase, such as Gigantic Jets and Sprites. The method makes it possible to fully remove from the observed waveform the distortions related to the receiver's impulse response as well as the influence of the Earth-ionosphere propagation channel. Our ELF station is equipped with two magnetic antennas for Bx and By components measurement in the 0.03 to 55 Hz frequency range. ELF Data recording is carried out since 1993, with continuous data acquisition since 2005. The station features low noise level and precise timing. It is battery powered and located in the sparsely populated area, far from major electric power lines, which results in high quality signal recordings and allows for precise calculations of the charge moments of upward discharges and strong cloud-to-ground discharges originating from distant sources. The same data is used for Schumann resonance observation. We demonstrate the use of our methods based on recent recordings from the Hylaty ELF station. We include examples of GJ (Gigantic Jet) and TGF (Terrestrial Gamma-ray Flash) related discharges.

Compilation of 1986 annual reports of the Navy ELF (extremely low frequency) communications system ecological-monitoring program. Volume 2. Tabs D-G. Annual progress report, January-December 1986

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1987-07-01

The U.S. Navy is conducting a long-term program to monitor for possible effects from the operation of its Extremely Low Frequency (ELF) Communications System to resident biota and their ecological relationships. This report documents progress of the following studies: Soil Amoeba; Soil and Litter Arthropoda and Earthworm Studies; Biological Studies on Pollinating insects: Megachilid Bees; and Small Vertebrates: Small Mammals and Nesting Birds.

Assessment of extremely low frequency magnetic field exposure from GSM mobile phones.

PubMed

Calderón, Carolina; Addison, Darren; Mee, Terry; Findlay, Richard; Maslanyj, Myron; Conil, Emmanuelle; Kromhout, Hans; Lee, Ae-kyoung; Sim, Malcolm R; Taki, Masao; Varsier, Nadège; Wiart, Joe; Cardis, Elisabeth

2014-04-01

Although radio frequency (RF) electromagnetic fields emitted by mobile phones have received much attention, relatively little is known about the extremely low frequency (ELF) magnetic fields emitted by phones. This paper summarises ELF magnetic flux density measurements on global system for mobile communications (GSM) mobile phones, conducted as part of the MOBI-KIDS epidemiological study. The main challenge is to identify a small number of generic phone models that can be used to classify the ELF exposure for the different phones reported in the study. Two-dimensional magnetic flux density measurements were performed on 47 GSM mobile phones at a distance of 25 mm. Maximum resultant magnetic flux density values at 217 Hz had a geometric mean of 221 (+198/-104) nT. Taking into account harmonic data, measurements suggest that mobile phones could make a substantial contribution to ELF exposure in the general population. The maximum values and easily available variables were poorly correlated. However, three groups could be defined on the basis of field pattern indicating that manufacturers and shapes of mobile phones may be the important parameters linked to the spatial characteristics of the magnetic field, and the categorization of ELF magnetic field exposure for GSM phones in the MOBI-KIDS study may be achievable on the basis of a small number of representative phones. Such categorization would result in a twofold exposure gradient between high and low exposure based on type of phone used, although there was overlap in the grouping. © 2013 Wiley Periodicals, Inc.

Effects on micronuclei formation of 60-Hz electromagnetic field exposure with ionizing radiation, hydrogen peroxide, or c-Myc overexpression.

PubMed

Jin, Yeung Bae; Kang, Ga-Young; Lee, Jae Seon; Choi, Jong-Il; Lee, Ju-Woon; Hong, Seung-Cheol; Myung, Sung Ho; Lee, Yun-Sil

2012-04-01

Epidemiological studies have demonstrated a possible correlation between exposure to extremely low-frequency magnetic fields (ELF-MF) and cancer. However, this correlation has yet to be definitively confirmed by epidemiological studies. The principal objective of this study was to assess the effects of 60 Hz magnetic fields in a normal cell line system, and particularly in combination with various external factors, via micronucleus (MN) assays. Mouse embryonic fibroblast NIH3T3 cells and human lung fibroblast WI-38 cells were exposed for 4 h to a 60 Hz, 1 mT uniform magnetic field with or without ionizing radiation (IR, 2 Gy), H(2)O(2) (100 μM) and cellular myelocytomatosis oncogene (c-Myc) activation. The results obtained showed no significant differences between the cells exposed to ELF-MF alone and the unexposed cells. Moreover, no synergistic effects were observed when ELF-MF was combined with IR, H(2)O(2), and c-Myc activation. Our results demonstrate that ELF-MF did not enhance MN frequency by IR, H(2)O(2) and c-Myc activation.

Influence of a 50 hz extra low frequency electromagnetic field on spermatozoa motility and fertilization rates in rabbits.

PubMed

Roychoudhury, Shubhadeep; Jedlicka, Jaroslav; Parkanyi, Vladimir; Rafay, Jan; Ondruska, Lubomir; Massanyi, Peter; Bulla, Jozef

2009-08-01

Effects of a 50 Hz extra-low frequency electromagnetic field (ELF EMF) on in vitro rabbit spermatozoa motility were analyzed, as well as the effect on fertilization rates after insemination. Pooled semen samples and a control were exposed to 50 Hz ELF EMF. The difference of the samples of the test groups G1 and G2 with the control group CG (75.56%) for spermatozoa motility were found to be significant (P < 0.01). Differences were significant (P < 0.01) for curvilinear velocity (VCL) between the test group G3 (122.38 microm/s) and the control group CG (112.02 microm/s). Hormonally stimulated adult (9-12 months) females (n = 140) were inseminated with semen samples from G1, G2, G3 and CG (0.88 x 109 spermatozoa/0.5 mL average insemination portion) immediately after ELF EMF exposure and fertilization (kindling) rates were calculated. For the G2 it was 54.28% data indicate 50 Hz ELF EMF induced alterations of spermatozoa motility and kindling rate in rabbits, therefore influencing fertility.

Onboard software of Plasma Wave Experiment aboard Arase: instrument management and signal processing of Waveform Capture/Onboard Frequency Analyzer

NASA Astrophysics Data System (ADS)

Matsuda, Shoya; Kasahara, Yoshiya; Kojima, Hirotsugu; Kasaba, Yasumasa; Yagitani, Satoshi; Ozaki, Mitsunori; Imachi, Tomohiko; Ishisaka, Keigo; Kumamoto, Atsushi; Tsuchiya, Fuminori; Ota, Mamoru; Kurita, Satoshi; Miyoshi, Yoshizumi; Hikishima, Mitsuru; Matsuoka, Ayako; Shinohara, Iku

2018-05-01

We developed the onboard processing software for the Plasma Wave Experiment (PWE) onboard the Exploration of energization and Radiation in Geospace, Arase satellite. The PWE instrument has three receivers: Electric Field Detector, Waveform Capture/Onboard Frequency Analyzer (WFC/OFA), and the High-Frequency Analyzer. We designed a pseudo-parallel processing scheme with a time-sharing system and achieved simultaneous signal processing for each receiver. Since electric and magnetic field signals are processed by the different CPUs, we developed a synchronized observation system by using shared packets on the mission network. The OFA continuously measures the power spectra, spectral matrices, and complex spectra. The OFA obtains not only the entire ELF/VLF plasma waves' activity but also the detailed properties (e.g., propagation direction and polarization) of the observed plasma waves. We performed simultaneous observation of electric and magnetic field data and successfully obtained clear wave properties of whistler-mode chorus waves using these data. In order to measure raw waveforms, we developed two modes for the WFC, `chorus burst mode' (65,536 samples/s) and `EMIC burst mode' (1024 samples/s), for the purpose of the measurement of the whistler-mode chorus waves (typically in a frequency range from several hundred Hz to several kHz) and the EMIC waves (typically in a frequency range from a few Hz to several hundred Hz), respectively. We successfully obtained the waveforms of electric and magnetic fields of whistler-mode chorus waves and ion cyclotron mode waves along the Arase's orbit. We also designed the software-type wave-particle interaction analyzer mode. In this mode, we measure electric and magnetic field waveforms continuously and transfer them to the mission data recorder onboard the Arase satellite. We also installed an onboard signal calibration function (onboard SoftWare CALibration; SWCAL). We performed onboard electric circuit diagnostics and antenna impedance measurement of the wire-probe antennas along the orbit. We utilize the results obtained using the SWCAL function when we calibrate the spectra and waveforms obtained by the PWE.[Figure not available: see fulltext.

Pilot study of extremely low frequency magnetic fields emitted by transformers in dwellings. Social aspects.

PubMed

Zaryabova, Victoria; Shalamanova, Tsvetelina; Israel, Michel

2013-06-01

A large number of epidemiologic studies examining the potential effect of residential exposure to extremely-low frequency (ELF) magnetic fields and childhood leukemia have been published. Two pooled analyses [Ahlbom A, Day N, Feychting M, Roman E, Skinner J, Dockerty J, Linet M, et al. (2000). A pooled analysis of magnetic fields and childhood leukaemia. Br J Cancer. 83(5):692-698; Greenland S, Sheppard AR, Kaune WT, Poole C, Kelsh AM (2000). A pooled analysis of magnetic fields, wire codes, and childhood leukemia. Epidemiology. 11(6):624-634], which included the major epidemiologic studies on ELF magnetic fields and childhood leukemia showed twofold increase in childhood leukemia risk in association with residential ELF exposure above 0.3-0.4 μT. Based on "limited" epidemiologic evidence linking ELF exposure to childhood leukemia and "inadequate evidence" for carcinogenicity of ELF in rodent bioassays, the International Agency for Research on Cancer (IARC) classified ELF magnetic fields as a possible human carcinogen (2B classification) [International Agency for Research on Cancer (IARC) (2002). Non-ionizing radiation, Part 1: Static and extremely low-frequency (ELF) electric and magnetic fields. IARC monographs on the evaluation of carcinogenic risks to humans. Vol. 80. IARC Press: Lyon], confirmed by WHO on the basis of studies published after 2000 [World Health Organization. Extremely low frequency fields. In: 238 Environmental health criteria, Geneva: WHO; 2007]. The analysis of more recent studies of ELF magnetic fields and childhood leukemia had small findings and propose methodological improvements concerning the uncertainties in epidemiological approaches and exposure assessment, bias in selection of controls [Kheifets L, Oksuzyan S (2008). Exposure assessment and other challenges in non-ionizing radiation studies of childhood leukaemia. Radiat Prot Dosimetry. 132(2):139-147]. By the end of 2010, 37 countries had been identified for possible participation in the International study TRANSEXPO. The pilot work has been completed in five countries (Finland, Hungary, Israel, Switzerland and Bulgaria). In 2008, Bulgaria through the National Centre of Public Health Protection joined with pilot study in TRANSEXPO Project. At this first stage of the project our investigation was directed to performing measurements in dwellings with built-in transformer stations, collecting data of population and cancer registry and choosing the epidemiology design feasible for continuing the project. Taking into account the available sources of information in Bulgaria (different registers of the population) needed for epidemiological approach, it was found that the most appropriate epidemiology design would be the nested case-control study. Control group could be collected in accordance with the international requirements for such epidemiological studies. This approach could be modified in the course of the further study in order to ensure achievement of the purposes of the main international requirements of the study.

Effect of ELF magnetic fields on lipid peroxidation, sperm count, p53, and trace elements.

PubMed

Akdag, M Zulkuf; Dasdag, Suleyman; Aksen, Feyzan; Isik, Birgul; Yilmaz, Fahri

2006-11-01

Some epidemiological and laboratory studies suggest a possible connection between extremely low-frequency (ELF) magnetic fields and certain illnesses, such as cancer, immune suppression, as well as reproductive toxic effects and abnormalities. Therefore, the aim of this study was to investigate the effects of ELF magnetic fields (1.35 mT) on sperm count, malondialdehyde concentration, the histology of such organs as the testes, brain, liver, and kidney tissues, p53 immunoreactivity of bone marrow, and the serum concentrations of Cu2+, Zn2+, Mn2+, and Fe3+ in rats. Sixteen Sprague-Dawley male rats were divided into two groups. The rats in the experimental group were exposed to an ELF magnetic field 2 hr/day for 2 months (7 days a week). The rats in the control group were not exposed to the ELF magnetic field. The exposure was performed in a Faraday cage (130 x 65 x 80 cm) with grounded shielding against the electric component. The Mann-Whitney U-test was used for the statistical analysis of the data. Magnetic field measurements showed that, under the experimental conditions, the magnetic field-exposure system produced a stable flux density of 1.35+/-0.018 mT and a stable frequency of 50 Hz, with negligible harmonics and no transients. However, no statistically significant alteration was observed in the parameters measured in this study except in Mn2+ concentrations (p<0.001). The present study found no evidence of an adverse effect of ELF magnetic fields on the measured parameters except for significantly increased Mn2+ concentrations (p<0.001).

Weak-field ELF magnetic interactions: Implications for biological change during paleomagnetic reversals.

PubMed

Liboff, Abraham R

2013-12-01

Contrary to the belief that paleomagnetic reversals are not biologically significant, we find good reason to think otherwise. Attention is drawn to polarity transitions, time intervals a few thousand years long that follow the collapse of the existing geomagnetic dipole moment and precede the establishment of the new, oppositely directed moment. The geomagnetic field during transitions is reduced to a maximal mean intensity about 10% of the stable field and can exhibit low-frequency perturbations comparable to numerous laboratory-based extremely low frequency (ELF) studies reporting biological interactions, making it very likely that similar interactions must occur over the course of a polarity transition. This conclusion is strengthened by reports of medical problems that significantly correlate with intense solar winds, events that also generate ELF perturbations similar to those that can occur during polarity transitions.

Severe storm electricity

NASA Technical Reports Server (NTRS)

Rust, W. D.; Macgorman, D. R.

1985-01-01

During FY-85, Researchers conducted a field program and analyzed data. The field program incorporated coordinated measurements made with a NASA U2. Results include the following: (1) ground truth measurements of lightning for comparison with those obtained by the U2; (2) analysis of dual-Doppler radar and dual-VHF lightning mapping data from a supercell storm; (3) analysis of synoptic conditions during three simultaneous storm systems on 13 May 1983 when unusually large numbers of positive cloud-to-ground (+CG) flashes occurred; (4) analysis of extremely low frequency (ELF) wave forms; and (5) an assessment of a cloud -ground strike location system using a combination of mobile laboratory and fixed-base TV video data.

Effects of Extremely Low-Frequency Electromagnetic Fields on Neurogenesis and Cognitive Behavior in an Experimental Model of Hippocampal Injury

PubMed Central

Sakhaie, Mohammad Hassan; Pourheydar, Bagher; Majd, Zahra; Atefimanesh, Pezhman

2017-01-01

Exposure to extremely low-frequency electromagnetic fields may induce constant modulation in neuronal plasticity. In recent years, tremendous efforts have been made to design a suitable strategy for enhancing adult neurogenesis, which seems to be deterred due to brain senescence and several neurodegenerative diseases. In this study, we evaluated the effects of ELF-EMF on neurogenesis and memory, following treatment with trimethyltin chloride (TMT) as a neurotoxicant. The mice in all groups (n = 56) were injected with BrdU during the experiment for seven consecutive days to label newborn cells. Spatial memory was assessed by the Morris water maze (MWM) test. By the end of the experiment, neurogenesis and neuronal differentiation were assessed in the hippocampus, using immunohistochemistry and Western blot analysis. Based on the findings, exposure to ELF-EMF enhanced spatial learning and memory in the MWM test. ELF-EMF exposure significantly enhanced the number of BrdU+ and NeuN+ cells in the dentate gyrus of adult mice (P < 0.001 and P < 0.05, resp.). Western blot analysis revealed significant upregulation of NeuroD2 in ELF-EMF-exposed mice compared to the TMT-treated group (P < 0.05). These findings suggest that ELF-EMF might have clinical implications for the improvement of neurodegenerative processes and could help develop a novel therapeutic approach in regenerative medicine. PMID:29259353

Extremely low frequency magnetic field measurements in buildings with transformer stations in Switzerland.

PubMed

Röösli, Martin; Jenni, Daniela; Kheifets, Leeka; Mezei, Gabor

2011-08-15

The aim of this study was to evaluate an exposure assessment method that classifies apartments in three exposure categories of extremely low frequency magnetic fields (ELF-MF) based on the location of the apartment relative to the transformer room. We completed measurements in 39 apartments in 18 buildings. In each room of the apartments ELF-MF was concurrently measured with 5 to 6 EMDEX II meters for 10 min. Measured arithmetic mean ELF-MF was 0.59 μT in 8 apartments that were fully adjacent to a transformer room, either directly above the transformer or touching the transformer room wall-to-wall. In apartments that only partly touched the transformer room at corners or edges, average ELF-MF level was 0.14 μT. Average exposure in the remaining apartments was 0.10 μT. Kappa coefficient for exposure classification was 0.64 (95%-CI: 0.45-0.82) if only fully adjacent apartments were considered as highly exposed (>0.4 μT). We found a distinct ELF-MF exposure gradient in buildings with transformer. Exposure classification based on the location of the apartment relative to the transformer room appears feasible. Such an approach considerably reduces effort for exposure assessment and may be used to eliminate selection bias in future epidemiologic studies. Copyright © 2011 Elsevier B.V. All rights reserved.

Interaction of biological systems with static and ELF electric and magnetic fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, L.E.; Kelman, B.J.; Weigel, R.J.

1987-01-01

Although background levels of atmospheric electric and geomagnetic field levels are extremely low, over the past several decades, human beings and other life forms on this planet have been subjected to a dramatically changing electromagnetic milieu. An exponential increase in exposure to electromagnetic fields has occurred, largely because of such technological advances as the growth of electrical power generation and transmission systems, the increased use of wireless communications, and the use of radar. In addition, electromagnetic field generating devices have proliferated in industrial plants, office buildings, homes, public transportation systems, and elsewhere. Although significant increases have occurred in electromagnetic fieldmore » strenghths spanning all frequency ranges, this symposium addresses only the impact of these fields at static and extremely low frequencies (ELF), primarily 50 and 60 Hz. This volume contains the proceedings of the symposium entitled /open quotes/Interaction of biological systems with static and ELF electric and magnetic fields/close quotes/. The purpose of the symposium was to provide a forum for discussions of all aspects of research on the interaction of static and ELF electromagnetic fields with biological systems. These systems include simple biophysical models, cell and organ preparations, whole animals, and man. Dosimetry, exposure system design, and artifacts in ELF bioeffects research were also addressed, along with current investigations that examine fundamental mechanisms of interactions between the fields and biological processes. Papers are indexed separately.« less

Effect of extremely low frequency electromagnetic fields on bacterial membrane.

PubMed

Oncul, Sule; Cuce, Esra M; Aksu, Burak; Inhan Garip, Ayse

2016-01-01

The effect of extremely low frequency electromagnetic fields (ELF-EMF) on bacteria has attracted attention due to its potential for beneficial uses. This research aimed to determine the effect of ELF-EMF on bacterial membrane namely the membrane potential, surface potential, hydrophobicity, respiratory activity and growth. Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli were subjected to ELF-EMF, 50 Hz, 1 mT for 2 h. Membrane potential was determined by fluorescence spectroscopy with or without EDTA (Ethylenediaminetetraacetic acid) with DisC3(5) (3,3-dipropylthiacarbocyanine iodide), zeta potential measurements were performed by electrophoretic mobility, hydrophobicity of the membrane was measured with MATH (Microbial Adhesion to Hydrocarbons) test, respiratory activity was determined with CTC (5-Cyano-2,3-ditolyl tetrazolium chloride), colony forming unit (CFU) and DAPI (4',6-diamidino-2-phenylindole, dihydrochloride) was used for growth determinations. ELF-EMF caused changes in physicochemical properties of both Gram-positive and Gram-negative bacteria. Hyperpolarization was seen in S. aureus and EDTA-treated E. coli. Surface potential showed a positive shift in S. aureus contrariwise to the negative shift seen in EDTA-untreated E. coli. Respiratory activity increased in both bacteria. A slight decrease in growth was observed. These results show that ELF-EMF affects the crucial physicochemical processes in both Gram-positive and Gram-negative bacteria which need further research.

ELF Waves Generated by Modulated HF Heating of the Auroral Electrojet and Observed at a Ground Distance of Approximately 4400 km

DTIC Science & Technology

2007-05-22

HAARP ) HF transmitter in Gakona, Alaska, and detected after propagating more than 4400 km in the Earth-ionosphere waveguide to Midway Atoll. The...conductivity variation (created by modulated HF heating) and radiating 4–32 W. The HF-ELF conversion efficiency at HAARP is thus estimated to be...Program ( HAARP ) research station in Gakona, Alaska. The HAARP HF transmitter (or heater), which JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112, A05309, doi

ELF Transients and Q-bursts Detected Around the Globe: First results from Palmer Station, Antarctica

NASA Astrophysics Data System (ADS)

Flint, Q. A.; Moore, R. C.

2016-12-01

We present the first analysis of data from the recently deployed broadband ELF (5-500 Hz) B-field receiver at Palmer Station, Antarctica together with observations at similar receivers located at Sondrestromfjord, Greenland and Arrival Heights, Antarctica. Such remote locations afford the unique opportunity to record signals that are essentially unperturbed by power line noise. As a result, using this multi-site global network of ELF/VLF receivers, we are able to easily detect a particular type of ELF transient that propagates around the world multiple times, known as the Q-burst. The Q-burst is characterized by a large increase in amplitude above the background at the Schumann Resonance modes and is believed to result from especially powerful cloud-to-ground lightning discharges. These powerful lightning discharges are likely responsible for a significant level of energetic coupling between the troposphere, the ionosphere, and the magnetosphere. The ELF and VLF waves excited by the lightning discharge propagate to great distances in the earth-ionosphere waveguide, and in fact propagate around the Earth multiple times. By measuring the received waveform at multiple distant sites around the globe, we can pinpoint the source lightning location, compare the changes in field strength and spectrum as a function of distance from the source, and evaluate modal propagation effects in the VLF range (that are not apparent in the ELF range).

Effects of time-variant extremely low-frequency (ELF) electromagnetic fields (EMF) on cholinesterase activity in Dictyostelium discoideum (Protista).

PubMed

Amaroli, Andrea; Trielli, Francesca; Bianco, Bruno; Giordano, Stefano; Moggia, Elsa; Corrado, Maria U Delmonte

2005-12-15

Recently, we detected propionylcholinesterase (PrChE) activity in single-cell amoebae of Dictyostelium discoideum using cytochemical, electrophoretic, and spectrophotometric methods. The involvement of this enzyme activity in cell-cell and cell-environment interactions was suggested. In this work, we found that exposure of single-cell amoebae to an extremely low-frequency electromagnetic fields (ELF-EMF) of 300 microT, 50 Hz, from 1 h up to 48 h at 21 +/- 1 degrees C affected PrChE activity.

A pilot investigation of the effect of extremely low frequency pulsed electromagnetic fields on humans' heart rate variability.

PubMed

Baldi, Emilio; Baldi, Claudio; Lithgow, Brian J

2007-01-01

The question whether pulsed electromagnetic field (PEMF) can affect the heart rhythm is still controversial. This study investigates the effects on the cardiocirculatory system of ELF-PEMFs. It is a follow-up to an investigation made of the possible therapeutic effect ELF-PEMFs, using a commercially available magneto therapeutic unit, had on soft tissue injury repair in humans. Modulation of heart rate (HR) or heart rate variability (HRV) can be detected from changes in periodicity of the R-R interval and/or from changes in the numbers of heart-beat/min (bpm), however, R-R interval analysis gives only a quantitative insight into HRV. A qualitative understanding of HRV can be obtained considering the power spectral density (PSD) of the R-R intervals Fourier transform. In this study PSD is the investigative tool used, more specifically the low frequency (LF) PSD and high frequency (HF) PSD ratio (LF/HF) which is an indicator of sympatho-vagal balance. To obtain the PSD value, variations of the R-R time intervals were evaluated from a continuously recorded ECG. The results show a HR variation in all the subjects when they are exposed to the same ELF-PEMF. This variation can be detected by observing the change in the sympatho-vagal equilibrium, which is an indicator of modulation of heart activity. Variation of the LF/HF PSD ratio mainly occurs at transition times from exposure to nonexposure, or vice versa. Also of interest are the results obtained during the exposure of one subject to a range of different ELF-PEMFs. This pilot study suggests that a full investigation into the effect of ELF-PEMFs on the cardiovascular system is justified.

Effects of Single and Repeated Exposure to a 50-Hz 2-mT Electromagnetic Field on Primary Cultured Hippocampal Neurons.

PubMed

Zeng, Ying; Shen, Yunyun; Hong, Ling; Chen, Yanfeng; Shi, Xiaofang; Zeng, Qunli; Yu, Peilin

2017-06-01

The prevalence of domestic and industrial electrical appliances has raised concerns about the health risk of extremely low-frequency magnetic fields (ELF-MFs). At present, the effects of ELF-MFs on the central nervous system are still highly controversial, and few studies have investigated its effects on cultured neurons. Here, we evaluated the biological effects of different patterns of ELF-MF exposure on primary cultured hippocampal neurons in terms of viability, apoptosis, genomic instability, and oxidative stress. The results showed that repeated exposure to 50-Hz 2-mT ELF-MF for 8 h per day after different times in culture decreased the viability and increased the production of intracellular reactive oxidative species in hippocampal neurons. The mechanism was potentially related to the up-regulation of Nox2 expression. Moreover, none of the repeated exposure patterns had significant effects on DNA damage, apoptosis, or autophagy, which suggested that ELF-MF exposure has no severe biological consequences in cultured hippocampal neurons.

TRI-SERVICE ELF COMMUNICATIONS - VOL. II, BIBLIOGRAPHY.

DTIC Science & Technology

BIBLIOGRAPHIES, UNDERGROUND ANTENNAS , ELECTRICAL RESISTANCE, UNDERGROUND , COSTS, VERY LOW FREQUENCY, LOW FREQUENCY, PROPAGATION, NOISE(RADIO)....EXTREMELY LOW FREQUENCY), (*COMMAND AND CONTROL SYSTEMS, COMMUNICATION AND RADIO SYSTEMS), (* COMMUNICATION AND RADIO SYSTEMS, MILITARY RESEARCH

Can safe and long-term exposure to extremely low frequency (50 Hz) magnetic fields affect apoptosis, reproduction, and oxidative stress?

PubMed

Akdag, Mehmet Zulkuf; Dasdag, Suleyman; Uzunlar, Ali Kemal; Ulukaya, Engin; Oral, Arzu Yilmaztepe; Çelik, Necla; Akşen, Feyzan

2013-12-01

To determine whether 50 Hz extremely low frequency-magnetic fields (ELF-MF) affects apoptotic processes, oxidative damage, and reproductive characteristics such as sperm count and morphology in rat testes. Thirty male Sprague-Dawley rats were used in the present study, which were divided into three groups (sham group, n = 10, and two experimental groups, n = 10 for each group). Rats in the experimental group were exposed to 100 and 500 μT ELF-MF (2 h/day, 7 days/week, for 10 months) corresponding to exposure levels that are considered safe for humans. The same experimental procedures were applied to the sham group, but the ELF generator was turned off. Tissues from the testes were immunohistochemically stained for active (cleaved) caspase-3 in order to measure the apoptotic index by a semi-quantitative scoring system. The levels of catalase (CAT), malondialdehyde (MDA), myeloperoxidase (MPO), total antioxidative capacity (TAC), total oxidant status (TOS), and oxidative stress index (OSI) were also measured. Additionally, epididymal sperm count and sperm morphology was evaluated. There were no significant differences in the reproductive and oxidative stress parameters between the sham group and the exposed groups (p > 0.05). While no difference was observed between the final apoptosis score of the sham and the 100 μT ELF-MF group (p > 0.05), the final apoptosis score was higher in the 500 μT ELF-MF exposure group than in the sham group (p < 0.05). Long-term exposure to 100 μT and 500 μT ELF-MF did not affect oxidative or antioxidative processes, lipid peroxidation, or reproductive components such as sperm count and morphology in testes tissue of rats. However, long-term exposure to 500 μT ELF-MF did affect active-caspase-3 activity, which is a well-known apoptotic indicator.

Investigations of Relatively Easy To Construct Antennas With Efficiency in Receiving Schumann Resonances: Preparations for a Miniaturized Reconfigurable ELF Receiver

NASA Technical Reports Server (NTRS)

Farmer, Brian W.; Hannan, Robert C.

2003-01-01

Relatively little is known about the cavity between the Earth and the ionosphere, which opens opportunities for technological advances and unique ideas. One effective means to study this cavity is with extremely low frequency (ELF) antennas. Possible applications of these antennas are global weather prediction, earthquake prediction, planetary exploration, communication, wireless transmission of power, or even a free energy source. The superconducting quantum interference device SQUID) and the coil antenna are the two most acceptable receivers discovered for picking up ELF magnetic fields. Both antennas have the potential for size reduction, allowing them to be portable enough for access to space and even for personal ware. With improvements of these antennas and signal processing, insightful analysis of Schumann resonance (SR) can give the science community a band of radio frequency (RF) signals for improving life here on Earth and exploring beyond.

Compilation of annual reports of the Navy ELF (Extremely Low Frequency) communications system ecological monitoring program (1983). Volume 2: Tabs F-J

NASA Astrophysics Data System (ADS)

Fischer, R. L.; Beaver, D. L.; Asher, J. H.; Hill, R. W.; Burton, T. M.

1984-07-01

The climatic factors which are known to impinge upon the biological behavior patterns of the megachilid bees were measured. Statistical testing of man-made influences such as ELF into the environment were pursued, with emphasis on nest architecture, pollen collection, and ability to orient to nest sites.

Efficacy of extremely low-frequency magnetic field in fibromyalgia pain: A pilot study.

PubMed

Paolucci, Teresa; Piccinini, Giulia; Iosa, Marco; Piermattei, Cristina; de Angelis, Simona; Grasso, Maria Rosaria; Zangrando, Federico; Saraceni, Vincenzo Maria

2016-01-01

The purpose of this pilot study was to determine the efficacy of an extremely low-frequency magnetic field (ELF-MF) in decreasing chronic pain in fibromyalgia (FM) patients. Thirty-seven females were recruited and randomized into two groups: one group was first exposed to systemic ELF-MF therapy (100 microtesla, 1 to 80 Hz) and then to sham therapy, and the other group received the opposite sequence of intervention. Pain, FM-related symptoms, and the ability to perform daily tasks were measured using the Visual Analog Scale, Fibromyalgia Impact Questionnaire (FIQ), Fibromyalgia Assessment Scale (FAS), and Health Assessment Questionnaire (HAQ) at baseline, end of first treatment cycle, beginning of second treatment cycle (after 1 mo washout), end of second treatment cycle, and end of 1 mo follow-up. ELF-MF treatment significantly reduced pain, which increased on cessation of therapy but remained significantly lower than baseline levels. Short-term benefits were also observed in FIQ, FAS, and HAQ scores, with less significant effects seen in the medium term. ELF-MF therapy can be recommended as part of a multimodal approach for mitigating pain in FM subjects and improving the efficacy of drug therapy or physiotherapy.

Interactions between occupational exposure to extremely low frequency magnetic fields and chemicals for brain tumour risk in the INTEROCC study.

PubMed

Turner, Michelle C; Benke, Geza; Bowman, Joseph D; Figuerola, Jordi; Fleming, Sarah; Hours, Martine; Kincl, Laurel; Krewski, Daniel; McLean, Dave; Parent, Marie-Elise; Richardson, Lesley; Sadetzki, Siegal; Schlaefer, Klaus; Schlehofer, Brigitte; Schüz, Joachim; Siemiatycki, Jack; Tongeren, Martie van; Cardis, Elisabeth

2017-11-01

In absence of clear evidence regarding possible effects of occupational chemical exposures on brain tumour aetiology, it is worthwhile to explore the hypothesis that such exposures might act on brain tumour risk in interaction with occupational exposure to extremely low frequency magnetic fields (ELF). INTEROCC is a seven-country (Australia, Canada, France, Germany, Israel, New Zealand and UK), population-based, case-control study, based on the larger INTERPHONE study. Incident cases of primary glioma and meningioma were ascertained from 2000 to 2004. Job titles were coded into standard international occupational classifications and estimates of ELF and chemical exposures were assigned based on job-exposure matrices. Dichotomous indicators of cumulative ELF (≥50th vs <50th percentile, 1-4 year exposure time window) and chemical exposures (ever vs never, 5-year lag) were created. Interaction was assessed on both the additive and multiplicative scales. A total of 1939 glioma cases, 1822 meningioma cases and 5404 controls were included in the analysis, using conditional logistic regression. There was no clear evidence for interactions between ELF and any of the chemical exposures assessed for either glioma or meningioma risk. For glioma, subjects in the low ELF/metal exposed group had a lower risk than would be predicted from marginal effects. Results were similar according to different exposure time windows, to cut-points of exposure or in exposed-only analyses. There was no clear evidence for interactions between occupational ELF and chemical exposures in relation to glioma or meningioma risk observed. Further research with more refined estimates of occupational exposures is recommended. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Coupling Mechanism of Electromagnetic Field and Thermal Stress on Drosophila melanogaster

PubMed Central

Yang, Chuan-Jun; Lian, Hui-Yong; Yu, Hui; Huang, Xiao-Mei; Cai, Peng

2016-01-01

Temperature is an important factor in research on the biological effects of extremely low-frequency electromagnetic field (ELF-EMF), but interactions between ELF-EMF and temperature remain unknown. The effects of ELF-EMF (50 Hz, 3 mT) on the lifespan, locomotion, heat shock response (HSR), and oxidative stress (OS) of Canton-Special (CS) and mutant w1118 flies were investigated at 25°C and 35°C (thermal stress). Results showed that thermal stress accelerated the death rates of CS and w1118 flies, shortened their lifespan, and influenced their locomotion rhythm and activity. The upregulated expression levels of heat shock protein (HSP) 22, HSP26, and HSP70 indicated that HSR was enhanced. Thermal stress-induced OS response increased malondialdehyde content, enhanced superoxide dismutase activity, and decreased reactive oxygen species level. The effects of thermal stress on the death rates, lifespan, locomotion, and HSP gene expression of flies, especially w1118 line, were also enhanced by ELF-EMF. In conclusion, thermal stress weakened the physiological function and promoted the HSR and OS of flies. ELF-EMF aggravated damages and enhanced thermal stress-induced HSP and OS response. Therefore, thermal stress and ELF-EMF elicited a synergistic effect. PMID:27611438

Generation of extremely low frequency chorus in Van Allen radiation belts: ELF CHORUS GENERATION

DOE PAGES

Xiao, Fuliang; Liu, Si; Tao, Xin; ...

2017-01-01

Recent studies have shown that chorus can efficiently accelerate the outer radiation belt electrons to relativistic energies. Chorus, previously often observed above 0.1 equatorial electron gyrofrequency f ce, was generated by energetic electrons originating from Earth's plasmasheet. Chorus below 0.1 f ce has seldom been reported until the recent data from Van Allen Probes but its origin has not been revealed so far. Because electron resonant energy can approach the relativistic level at extremely low frequency relativistic effects should be considered in the formula for whistler-mode wave growth rate. Here we report high-resolution observations during the 14 October 2014 smallmore » storm and firstly demonstrate, using a fully relativistic simulation, that electrons with the high energy tail population and relativistic pitch angle anisotropy can provide free energy sufficient for generating chorus below 0.1 f ce. The simulated wave growth displays a very similar pattern to the observations. Finally, the current results can be applied to Jupiter, Saturn and other magnetized planets.« less

International Conference on Antennas and Propagation (ICAP 89), 6th, University of Warwick, Coventry, England, Apr. 4-7, 1989, Proceedings. Part 1 - Antennas. Part 2 - Propagation

NASA Astrophysics Data System (ADS)

Various papers on antennas and propagation are presented. The general topics addressed include: phased arrays; reflector antennas; slant path propagation; propagation data for HF radio systems performance; satellite and earth station antennas; radio propagation in the troposphere; propagation data for HF radio systems performance; microstrip antennas; rain radio meteorology; conformal antennas; horns and feed antennas; low elevation slant path propagation; radio millimeter wave propagation; array antennas; propagation effects on satellite mobile, satellite broadcast, and aeronautical systems; ionospheric irregularities and motions; adaptive antennas; transient response; measurement techniques; clear air radio meteorology; ionospheric and propagation modeling; millimeter wave and lens antennas; electromagnetic theory and numerical techniques; VHF propagation modeling, system planning methods; radio propagation theoretical techniques; scattering and diffraction; transhorizon rain scatter effects; ELF-VHF and broadcast antennas; clear air millimeter propagation; scattering and frequency-selective surfaces; antenna technology; clear air transhorizon propagation.

Assessments and Viewpoints on the Biological and Human Health Effects of Extremely Low Frequency (ELF) Electromagnetic Fields. Compilation of Commissioned Papers for the ELF Literature Review Project.

DTIC Science & Technology

1985-05-01

Environ. Biophys. 20:53-65. 1983. Electric field effects on bacteria and yeast cells . Radiat. Environ. Biophys. 22 :149-162. Husing, J. 0., F. Strauss, and...Jr., Ph.D. 141 A Review of Cell Effects Induced by Exposure of Extremely Low 155 Frequency Electromagnetic Fields - Eugene M. Goodman, Ph.D. and Ben...and E. M. Goodman. 1983. Cell surface effects of 60 Hz electromagnetic fields. Radiat. Res. 94:217-220. artucci, G. I., P. C. Gailey, and R. A. Tell

Extremely Low Frequency Vertical, 45-Hz Electric Field Exposure of Rats: A Search for Growth, Food, and Water Consumption, Blood Metabolite, Hematological, and Pathological Changes

DTIC Science & Technology

1977-06-01

radiation having frequencies’from a few hertz (sometimes including zero hertz or de) to several hundred hertz. The natural or ambient levels of ELF...that sharks and rays can locate prey by the weak ELF electric fields they produce, and that some fish may also be able to use terrestrial fields in...fixed level if a real effect is present. The field strength of 20 V/rn (RMS) was chosen because this value produced the effects observed by Noval et

Design and fabrication of a microplatform for the proximity effect study of localized ELF-EMF on the growth of in vitro HeLa and PC-12 cells

NASA Astrophysics Data System (ADS)

Chen, Y. C.; Chen, C. C.; Tu, W.; Cheng, Y. T.; Tseng, F. G.

2010-12-01

This paper presents a platform technology with experimental results that show the scientists and biologists a way to rapidly investigate and analyze the biological effects of localized extremely low frequency (ELF) electromagnetic field (EMF) on living cells. The proximity effect of the localized ELF-EMF on living cells is revealed using the bio-compatible microplatform on which an on-glass inductive coil array, the source of the localized ELF-EMF in micro scale, is designed, fabricated and operated with a field strength of 1.2 ± 0.1 mT at 60 Hz for cell culturing study. After a 72 h ELF-EMF exposure, HeLa (human cervical cancer) and PC-12 (rat pheochromocytoma) cells exhibit about 18.4% and 12.9% cell proliferation rate reduction, respectively. Furthermore, according to the presented dynamic model, the reduction of the proliferation can be attributed to the interference of signal transduction processes due to the tangential currents induced around the cells.

No effects of intermittent 50 Hz EMF on cytoplasmic free calcium and on the mitochondrial membrane potential in human diploid fibroblasts.

PubMed

Pilger, Alexander; Ivancsits, Sabine; Diem, Elisabeth; Steffens, Melanie; Kolb, Hans-Albert; Rüdiger, Hugo W

2004-09-01

The recently described increase in DNA strand breaks of cultured human diploid fibroblasts after intermittent exposure to extremely-low-frequency electromagnetic fields (ELF-EMF) of more than about 70 microT ELF-EMF is difficult to explain by a direct induction of covalent bond disruption. Therefore the hypothesis has been tested that ELF-EMF-induced DNA strand breaks might be mediated by cellular processes that cause alteration of the intracellular concentration of free calcium ([Ca2+]i) and/or the membrane potential (DeltaPsi(m)). [Ca2+]i was determined by the ratiometric fura-2 technique. Changes in DeltaPsi(m) were assessed by using the potential-dependent lipophilic cationic probe JC-1. Human fibroblasts were exposed to intermittent ELF-EMF (50 Hz, 1000 microT). Although exposure of fiboblasts to ELF-EMF resulted in a highly significant increase in DNA strand breaks as determined by the comet assay, no effect on JC-1 fluorescence emission or on [Ca2+]i has been observed when comparing exposed with sham-exposed cells. Therefore, it is suggested that ELF-EMF-induced DNA strand breaks are unlikely to be caused by intracellular changes that affect [Ca2+]i and/or DeltaPsi(m).

ELF (Extremely Low Frequency) Communications System Ecological Monitoring Program: Summary of 1987 Progress

DTIC Science & Technology

1989-04-01

Development . Prenatal developmental stages are especially sensitive to environmental perturbations. At present, there is conflicting evidence of direct EM...effects on embryonic or fetal development . In addition, possible effects of the ELF system on parental behavior could also have an indirect effect on... development . The purpose of this element is to determine the incidence of abnormalities in embryonic development in tree swallows at treatment and control

Exposure to extremely low frequency electromagnetic fields alters the behaviour, physiology and stress protein levels of desert locusts

PubMed Central

Wyszkowska, Joanna; Shepherd, Sebastian; Sharkh, Suleiman; Jackson, Christopher W.; Newland, Philip L.

2016-01-01

Electromagnetic fields (EMFs) are present throughout the modern world and are derived from many man-made sources including overhead transmission lines. The risks of extremely-low frequency (ELF) electromagnetic fields are particularly poorly understood especially at high field strengths as they are rarely encountered at ground level. Flying insects, however, can approach close to high field strength transmission lines prompting the question as to how these high levels of exposure affect behaviour and physiology. Here we utilise the accessible nervous system of the locust to ask how exposure to high levels of ELF EMF impact at multiple levels. We show that exposure to ELF EMFs above 4 mT leads to reduced walking. Moreover, intracellular recordings from an identified motor neuron, the fast extensor tibiae motor neuron, show increased spike latency and a broadening of its spike in exposed animals. In addition, hind leg kick force, produced by stimulating the extensor tibiae muscle, was reduced following exposure, while stress-protein levels (Hsp70) increased. Together these results suggest that ELF EMF exposure has the capacity to cause dramatic effects from behaviour to physiology and protein expression, and this study lays the foundation to explore the ecological significance of these effects in other flying insects. PMID:27808167

Effects of extremely low-frequency magnetotherapy on proliferation of human dermal fibroblasts.

PubMed

Pasi, Francesca; Sanna, Samuele; Paolini, Alessandro; Alquati, Marco; Lascialfari, Alessandro; Corti, Maurizio Enrico; Liberto, Riccardo Di; Cialdai, Francesca; Monici, Monica; Nano, Rosanna

2016-01-01

Extremely low-frequency electromagnetic fields (ELF-EMFs) applied in magnetotherapy have frequency lower than 100 Hz and magnetic field intensity ranging from 0.1 to 20 mT. For many years, the use of magnetotherapy in clinics has been increasing because of its beneficial effects in many processes, e.g., skin diseases, inflammation and bone disorders. However, the understanding of the microscopic mechanisms governing such processes is still lacking and the results of the studies on the effects of ELF-EMFs are controversial because effects derive from different conditions and from intrinsic responsiveness of different cell types.In the present study, we studied the biological effects of 1.5 h exposure of human dermal fibroblasts to EMFs with frequencies of 5 and 50 Hz and intensity between 0.25 and 1.6 mT. Our data showed that the magnetic treatment did not produce changes in cell viability, but gave evidence of a sizeable decrease in proliferation at 24 h after treatment. In addition, immunofluorescence experiments displayed an increase in tubulin expression that could foreshadow changes in cell motility or morphology. The decrease in proliferation with unchanged viability and increase in tubulin expression could be consistent with the triggering of a transdifferentiation process after the exposure to ELF-EMFs.

Vitamin C and Vitamin E Protected B95-8 and Balb/c-3T3 Cells from Apoptosis Induced by Intermittent 50Hz ELF-EMF Radiation.

PubMed

Ding, Zhen; Li, Jintao; Li, Fan; Mephryar, Mohammadreza Mohammadzad; Wu, Shuicai; Zhang, Chen; Zeng, Yi

2017-01-01

The extremely low-frequency electromagnetic field (ELF-EMF), mainly emitted by electric transmission lines and household electronic appliances, is becoming a worldwide health risk. It is imperative to investigate the biological impacts of ELF-EMF and to identify products that are resistant to the radiation from 50 Hz ELF-EMF. In this study, we investigated the biological impacts of apoptosis caused by 50 Hz Power line ELF-EMF and the protective effects of Vit C and Vit E. We conducted this study in Beijing, China in 2013. B 95-8 and Balb/c-3T3 cells were divided into a sham group, an expo group and 3 expo groups in which the cells were preincubated with various concentrations of Vit C and Vit E. Then, all of the cells were exposed to 50 Hz Power line ELF-EMF and examined for apoptosis. The cells were collected for apoptosis detection after exposure. The percent of cells that undergoing apoptosis and preincubated with various concentrations of Vit C and Vit E were significantly lower than in the Expo group. Vit C and Vit E exert significant protective effects from 50 Hz ELF-EMF radiation. The optimal protective concentrations of Vit C and Vit E are 10 μmol/L and 25 μmol/L, respectively. The protective effect of vitamins was more apparent for Balb/c-3T3 cells than B 95-8 cells.

Low frequency electric and magnetic fields

NASA Technical Reports Server (NTRS)

Spaniol, Craig

1989-01-01

Following preliminary investigations of the low frequency electric and magnetic fields that may exists in the Earth-ionospheric cavity, measurements were taken with state-of-the art spectrum analyzers. As a follow up to this activity, an investigation was initiated to determine sources and values for possible low frequency signal that would appear in the cavity. The lowest cavity resonance is estimated at about 8 Hz, but lower frequencies may be an important component of our electromagnetic environment. The potential field frequencies produced by the electron were investigated by a classical model that included possible cross coupling of the electric and gravitation fields. During this work, an interesting relationship was found that related the high frequency charge field with the extremely low frequency of the gravitation field. The results of numerical calculations were surprisingly accurate and this area of investigation is continuing. The work toward continued development of a standardized monitoring facility is continuing with the potential of installing the prototype at West Virginia State College early in 1990. This installation would be capable of real time monitoring of ELF signals in the Earth-ionoshpere cavity and would provide some directional information. A high gain, low noise, 1/f frequency corrected preamplifier was designed and tested for the ferrite core magnetic sensor. The potential application of a super conducting sensor for the ELF magnetic field detection is under investigation. It is hoped that a fully operational monitoring network could pinpoint the location of ELF signal sources and provide new information on where these signals originate and what causes them, assuming that they are natural in origin.

Nature of Pre-Earthquake Phenomena and their Effects on Living Organisms

PubMed Central

Freund, Friedemann; Stolc, Viktor

2013-01-01

Simple Summary Earthquakes are invariably preceded by a period when stresses increase deep in the Earth. Animals appear to be able to sense impending seismic events. During build-up of stress, electronic charge carriers are activated deep below, called positive holes. Positive holes have unusual properties: they can travel fast and far into and through the surrounding rocks. As they flow, they generate ultralow frequency electromagnetic waves. When they arrive at the Earth surface, they can ionize the air. When they flow into water, they oxidize it to hydrogen peroxides. All these physical and chemical processes can have noticeable effects on animals. Abstract Earthquakes occur when tectonic stresses build up deep in the Earth before catastrophic rupture. During the build-up of stress, processes that occur in the crustal rocks lead to the activation of highly mobile electronic charge carriers. These charge carriers are able to flow out of the stressed rock volume into surrounding rocks. Such outflow constitutes an electric current, which generates electromagnetic (EM) signals. If the outflow occurs in bursts, it will lead to short EM pulses. If the outflow is continuous, the currents may fluctuate, generating EM emissions over a wide frequency range. Only ultralow and extremely low frequency (ULF/ELF) waves travel through rock and can reach the Earth surface. The outflowing charge carriers are (i) positively charged and (ii) highly oxidizing. When they arrive at the Earth surface from below, they build up microscopic electric fields, strong enough to field-ionize air molecules. As a result, the air above the epicentral region of an impending major earthquake often becomes laden with positive airborne ions. Medical research has long shown that positive airborne ions cause changes in stress hormone levels in animals and humans. In addition to the ULF/ELF emissions, positive airborne ions can cause unusual reactions among animals. When the charge carriers flow into water, they oxidize water to hydrogen peroxide. This, plus oxidation of organic compounds, can cause behavioral changes among aquatic animals. PMID:26487415

Treatment of Diabetic Foot Ulcers through Systemic Effects of Extremely Low Frequency Electromagnetic Fields

NASA Astrophysics Data System (ADS)

Trejo-Núñez, A. D.; Pérez-Chávez, F.; García-Sánchez, C.; Serrano-Luna, G.; Cañendo-Dorantes, L.

2008-08-01

This study was designed to, investigate the healing effects of extremely low frequency electromagnetic fields (ELF-EMF) on diabetic foot ulcers and test two different exposure systems aimed at reducing the ELF-EMF exposure time of patients. In the first system the ELF-EMF were applied to the arm where only 3% of the total blood volume/min circulates at any given time. In the second system the ELF-EMF were applied to the thorax where more than 100% of the total blood volume/minute circulates at any given time. Twenty-six diabetic patients, with superficial neuropathic ulcers unresponsive to medical treatment were included in this preliminary report. In the first group (17 patients), the arm was exposed two hours twice a week to a extremely low frequency electromagnetic field of 0.45-0.9 mTrms, 120 Hz generated inside a solenoid coil of 10.1 cm by 20.5 cm long. In the second group the thorax of 7 patients was exposed 25 minutes twice a week to an electromagnetic field of 0.4-0.85 mTrms, 120 Hz generated in the center of a squared quasi-Helmholtz coil 52 cm by side. One patient was assigned to a placebo configuration of each exposure system with identical appearance as the active equipment but without magnetic field. Patients with deep ulcers, infected ulcers, cancer, or auto-immune disease were excluded. These preliminary results showed that the two exposure systems accelerate the healing process of neuropathic ulcers. Complete healing of the ulcer had a median duration of 90 days in both exposure systems. Therefore thorax exposure where more blood is exposed to ELF-EMF per unit of time was able to reduce 4.8 times the patient treatment time. In those patients assigned to the placebo equipment no healing effects were observed. This study will continue with a parallel, double blind placebo controlled protocol.

Living Organisms Coupling to Electromagnetic Radiation Below Thermal Noise

NASA Astrophysics Data System (ADS)

Stolc, Viktor; Freund, Friedemann

2013-04-01

Ultralow frequency (ULF) and extremely low frequency (ELF) electromagnetic (EM) radiation is part of the natural environment. Prior to major earthquakes the local ULF and global ELF radiation field is often markedly perturbed. This has detrimental effects on living organisms. We are studying the mechanism of these effects on the biochemical, cellular and organismal levels. The transfer of electrons along the Electron Transfer Chain (ETC) controls the universal reduction-oxidation reactions that are essential for fundamental biochemical processes in living cells. In order for these processes to work properly, the ETC has to maintain some form of synchronization, or coherence with all biochemical reactions in the living cells, including energy production, RNA transcription, and DNA replication. As a consequence of this synchronization, harmful chemical conflict between the reductive and the oxidative partial reactions can be minimized or avoided. At the same time we note that the synchronization allows for a transfer of energy, coherent or interfering, via coupling to the natural ambient EM field. Extremely weak high frequency EM fields, well below the thermal noise level, tuned in frequency to the electron spins of certain steps in the ETC, have already been shown to cause aberrant cell growth and disorientation among plants and animals with respect to the magnetic and gravity vectors. We investigate EM fields over a much wider frequency range, including ULF known to be generated deep in the Earth prior to major earthquakes locally, and ELF known to be fed by lightning discharges, traveling around the globe in the cavity formed between the Earth's surface and the ionosphere. This ULF/ELF radiation can control the timing of the biochemical redox cycle and thereby have a universal effect on physiology of organisms. The timing can even have a detrimental influence, via increased oxidative damage, on the DNA replication, which controls heredity.

Suppression of type I collagen in human scleral fibroblasts treated with extremely low-frequency electromagnetic fields

PubMed Central

Wang, Jie; Cui, Jiefeng

2013-01-01

Purpose To investigate the expression differences of type I collagen (COL1A1) and its underlying mechanisms in human fetal scleral fibroblasts (HFSFs) that were treated with conditioned medium from retinal pigment epithelial (RPE) cells under extremely low-frequency electromagnetic fields (ELF-EMFs). Methods The ELF-EMFs used in this study were established by slidac and artificial coils. Growth of the treated HFSFs was evaluated by a cell-counting kit-8 assay. The expression of COL1A1 and matrix metalloproteinases-2 (MMP-2) in the treated HFSFs was detected by reverse transcription PCR (RT-PCR) and western blot, and the expression of transforming growth factor-β2 (TGF-β2) and basic fibroblast growth factor-2 (FGF-2) in RPE cells exposed to EMFs was detected by RT-PCR. The expression of COL1A1 and MMP-2 in HFSFs was further confirmed by immunofluorescence staining. Activation of extracellular signal-regulated kinase 1/2 (ERK1/2 also called p44/p42 mitogen-activated protein kinases [MAPK]) and p38 in HFSFs was measured by western blot. Results We found that exposure to ELF-EMFs resulted in a decreased proliferation rate of HFSFs and that addition of RPE supernatant medium could enhance this effect. Compared with that of the control cells, a significant decrease in collagen synthesis was detected in HFSFs under ELF-EMFs. However, the expression of MMP-2 was upregulated, which could be further enhanced via an RPE supernatant additive. The activities of ERK1/2 and p38 were significantly increased in HFSFs exposed to ELF-EMFs, and this effect could be enhanced by RPE supernatant medium additive. Conclusions Our results suggested that ELF-EMFs can inhibit the expression of type I collagen in HFSFs and contribute to the remodeling of the sclera. PMID:23592926

Effect of extremely low frequency magnetic field on antioxidant activity in plasma and red blood cells in spot welders.

PubMed

Sharifian, Akbar; Gharavi, Marjan; Pasalar, Parvin; Aminian, Omid

2009-01-01

The purpose of this study was to determine a possible relation between exposure to extremely low frequency magnetic field (ELF-MF) and the human antioxidant activity. The total serum antioxidant status (TAS), red blood cells (RBCs) glutathione peroxidase (GPX) and superoxide dismutase (SOD) were measured in 46 spot welders who were occupationally exposed to ELF-MF (magnetic field strength = 8.8-84 microTesla (microT), frequency = 50 Hertz (Hz) and electric field strength = 20-133 V/m). The results were compared with a nonexposed ELF-MF control group. The correlation between magnetic field strength and antioxidant activity in RBCs and plasma was then assessed. No significant differences in TAS levels were observed (P value = 0.065). However, in RBCs of exposed group, a significant decrease in SOD and GPX activities was observed (P value = 0.001 and 0.003, respectively). This decrease was measured as 22 and 12.3%, respectively. Furthermore, a significant negative correlation between SOD/GPX activities and magnetic field intensity was observed (coefficients of SOD: -0.625, significance: 0.0001 and coefficients of GPX: -0.348, significance: 0.018). The results of this study indicate that ELF-MF could influence the RBC antioxidant activity and might act as an oxidative stressor. Intracellular antioxidant enzymes such as SOD and GPX were found to be the most important markers involving in this process. The influence of magnetic field on the antioxidant activity of RBCs might occur even at the recommended levels of exposure.

Accuracy of the Enhanced Liver Fibrosis Test vs FibroTest, Elastography, and Indirect Markers in Detection of Advanced Fibrosis in Patients With Alcoholic Liver Disease.

PubMed

Thiele, Maja; Madsen, Bjørn Stæhr; Hansen, Janne Fuglsang; Detlefsen, Sönke; Antonsen, Steen; Krag, Aleksander

2018-04-01

Alcohol is the leading cause of cirrhosis and liver-related mortality, but we lack serum markers to detect compensated disease. We compared the accuracy of the Enhanced Liver Fibrosis test (ELF), the FibroTest, liver stiffness measurements (made by transient elastography and 2-dimensional shear-wave elastography), and 6 indirect marker tests in detection of advanced liver fibrosis (Kleiner stage ≥F3). We performed a prospective study of 10 liver fibrosis markers (patented and not), all performed on the same day. Patients were recruited from primary centers (municipal alcohol rehabilitation, n = 128; 6% with advanced fibrosis) and secondary health care centers (hospital outpatient clinics, n = 161; 36% with advanced fibrosis) in the Region of Southern Denmark from 2013 through 2016. Biopsy-verified fibrosis stage was used as the reference standard. The primary aim was to validate ELF in detection of advanced fibrosis in patients with alcoholic liver disease recruited from primary and secondary health care centers, using the literature-based cutoff value of 10.5. Secondary aims were to assess the diagnostic accuracy of ELF for significant fibrosis and cirrhosis and to determine whether combinations of fibrosis markers increase diagnostic yield. The ELF identified patients with advanced liver fibrosis with an area under the receiver operating characteristic curve (AUROC) of 0.92 (95% confidence interval 0.89-0.96); findings did not differ significantly between patients from primary vs secondary care (P = .917). ELF more accurately identified patients with advanced liver fibrosis than indirect marker tests, but ELF and FibroTest had comparable diagnostic accuracies (AUROC of FibroTest, 0.90) (P = .209 for comparison with ELF). Results from the ELF and FibroTest did not differ significantly from those of liver stiffness measurement in intention-to-diagnose analyses (AUROC for transient elastography, 0.90), but did differ in the per-protocol analysis (AUROC for transient elastography, 0.97) (P = .521 and .004 for comparison with ELF). Adding a serum marker to transient elastography analysis did not increase accuracy. For patients in primary care, ELF values below 10.5 and FibroTest values below 0.58 had negative predictive values for advanced liver fibrosis of 98% and 94%, respectively. In a prospective, direct comparison of tests, ELF and FibroTest identified advanced liver fibrosis in alcoholic patients from primary and secondary care with high diagnostic accuracy (AUROC values of 0.90 or higher using biopsy as reference). Advanced fibrosis can be ruled out in primary health care patients based on an ELF value below 10.5 or a FibroTest value below 0.58. Copyright © 2018 AGA Institute. Published by Elsevier Inc. All rights reserved.

ELF/VLF propagation measurements in the Atlantic during 1989

NASA Astrophysics Data System (ADS)

Nickolaenko, A. P.

1995-06-01

The vertical electric field component was measured by a group of the Ukrainian Insitute of Radio Astronomy on board the Professor Zubov scientific vessel during April 1989 at latitudes from 30 deg S to 50 deg N. Results of the amplitude measurements in the Atlantic of natural ELF radio signals and those from the VLF navigation system 'Omega' at its lowest frequency of 10.2 kHz are given. Characteristics were obtained of the moving ship as the field-site for the ELF observations. Variations in the ELF radio noise amplitude recorded at tropical latitudes agree with the computed data for the model of three continental centers of lightning activity. The VLF results were obtained by the 'beat' technique providing the simplest narrow-band amplitude registration. Range dependencies of the field amplitudes from A (Norway), B (Liberia) and F (Argentina) stations have been analyzed. The VLF attentuation factor was estimated for the ambient day conditions along the four cardinal directions. This allowed the detection of a statistically significant attenuation difference between the east-west and west-east propagation paths. The VLF radio signal was also used as a probe to evaluate the effective height of the vertical electric antenna and to calibrate the ELF noise amplitudes.

A Meta-Analysis on the Relationship between Exposure to ELF-EMFs and the Risk of Female Breast Cancer

PubMed Central

Chen, Qingsong; Lang, Li; Wu, Wenzhe; Xu, Guoyong; Zhang, Xiao; Li, Tao; Huang, Hanlin

2013-01-01

Objective To comprehensively analyze the relationship between exposure to extremely low frequency electromagnetic fields (ELF-EMFs) and the development of female breast cancer. Methods Reports of case-control studies published from 1990 to 2010 were analyzed. The quality effect model was chosen to calculate total odds ratio (OR) depending on the data in studies and quality scores. Subgroup analyses were also performed by the situation of menopause, estrogenic receptor and exposure assessment respectively. Results For all 23 studies the OR was 1.07, 95% CI = 1.02–1.13, for estrogen receptor positive subgroup,OR = 1.11, 95% CI = 1.03–1.20; for premenopausal subgroup, OR = 1.11, 95% CI = 1.00–1.23. The results of other subgroups showed no significant association between ELF-EMF and female breast cancer. Conclusion ELF-EMFs might be related to an increased risk for female breast cancer, especially for premenopausal and ER+ females. However, it's necessary to undertake better epidemiologic researches to verify the association between ELF-EMF and female breast cancer due to the limits of current study, especially the one on exposure assessment. PMID:23869239

Plasma wave observations near the plasmapause with the S3-A satellite

NASA Technical Reports Server (NTRS)

Anderson, R. R.; Gurnett, D. A.

1972-01-01

The electric field noise phenomena is described which was observed by the S3-A spacecraft near the plasmapause during the magnetic storm of 16 to 17 December, 1971. The occurrence is noted of a region of intense, low frequency (20 Hz to 500 Hz) electrostatic noise bursts just outside the plasmapause boundary. These noise bursts occurred concurrent with the rapid decrease in 24.3 or = E or = 35.1 keV ring current protons mirroring near the equator during this storm and may be responsible for the pitch angle diffusion and loss of these particles. The characteristics of other phenomena, such as whistlers, ELF hiss, and banded chorus, observed near the plasmapause during this period are also discussed.

Vitamin C and Vitamin E Protected B95-8 and Balb/c-3T3 Cells from Apoptosis Induced by Intermittent 50Hz ELF-EMF Radiation

PubMed Central

DING, Zhen; LI, Jintao; LI, Fan; MEPHRYAR, Mohammadreza Mohammadzad; WU, Shuicai; ZHANG, Chen; ZENG, Yi

2017-01-01

Background: The extremely low-frequency electromagnetic field (ELF-EMF), mainly emitted by electric transmission lines and household electronic appliances, is becoming a worldwide health risk. It is imperative to investigate the biological impacts of ELF-EMF and to identify products that are resistant to the radiation from 50 Hz ELF-EMF. In this study, we investigated the biological impacts of apoptosis caused by 50 Hz Power line ELF-EMF and the protective effects of Vit C and Vit E. Methods: We conducted this study in Beijing, China in 2013. B95-8 and Balb/c-3T3 cells were divided into a sham group, an expo group and 3 expo groups in which the cells were preincubated with various concentrations of Vit C and Vit E. Then, all of the cells were exposed to 50 Hz Power line ELF-EMF and examined for apoptosis. The cells were collected for apoptosis detection after exposure. Results: The percent of cells that undergoing apoptosis and preincubated with various concentrations of Vit C and Vit E were significantly lower than in the Expo group. Conclusion: Vit C and Vit E exert significant protective effects from 50 Hz ELF-EMF radiation. The optimal protective concentrations of Vit C and Vit E are 10 μmol/L and 25 μmol/L, respectively. The protective effect of vitamins was more apparent for Balb/c-3T3 cells than B95-8 cells. PMID:28451526

Excitation of Earth-ionosphere waveguide in the ELF and lower VLF bands by modulated ionospheric current

NASA Astrophysics Data System (ADS)

Field, E. C.; Bloom, R. M.

1993-05-01

In this report, the principal of reciprocity is used in conjunction with a full-wave propagation code to calculate ground-level fields excited by ionospheric currents modulated at frequencies between 50 and 100 Hz with HF heaters. Results show the dependence on source orientation, altitude, and dimension and therefore pertain to experiments using the HIPAS or HAARP ionospheric heaters. In the end-fire mode, the waveguide excitation efficiency of an ELF HED in the ionosphere is up to 20 dB greater than for a ground-based antenna, provided its altitude does not exceed 80 to 90 km. The highest efficiency occurs for a source altitude of around 70 km; if that altitude is raised to 100 km, the efficiency drops by about 20 dB in the day and 10 dB at night. That efficiency does not account for the greater conductivity modulation that might be achieved at altitudes greater than 70 km, however. The trade-off between the altitude dependencies of the excitation efficiency and maximum achievable modulation depends on the ERP of the HF heater, the optimum altitude increasing with increasing ERP. For HIPAS the best modulation altitude is around 70 km, whereas for HAARP there might be marginal value in modulating at attitudes as high as 100 km.

Extremely Low Frequency (ELF) Communications System Ecological Monitoring Program: Plan and Summary of 1982 Progress.

DTIC Science & Technology

1983-08-01

Program Acquisition Schedule A-8 LIST OF TABLES TABLE TITLE Page 1 Evolution of the ELF Communications Ecological 2 Moni tori ng Program 2 Summary of...performed on plots in maple-dominant, mixed hardwood stands in Michigan. NATIVE BEES Bees are important pollinators of flowering plants and are...SMALL MAMMALS AND NESTING BIRDS Small mammals and nesting birds represent an ecological level inter- mediate between plants and strict carnivores

Children’s Personal Exposure Measurements to Extremely Low Frequency Magnetic Fields in Italy

PubMed Central

Liorni, Ilaria; Parazzini, Marta; Struchen, Benjamin; Fiocchi, Serena; Röösli, Martin; Ravazzani, Paolo

2016-01-01

Extremely low frequency magnetic fields (ELF-MFs) exposure is still a topic of concern due to their possible impact on children’s health. Although epidemiological studies claimed an evidence of a possible association between ELF-MF above 0.4 μT and childhood leukemia, biological mechanisms able to support a causal relationship between ELF-MF and this disease were not found yet. To provide further knowledge about children’s ELF-MF exposure correlated to children’s daily activities, a measurement study was conducted in Milan (Italy). Eighty-six children were recruited, 52 of whom were specifically chosen with respect to the distance to power lines and built-in transformers to oversample potentially highly exposed children. Personal and bedroom measurements were performed for each child in two different seasons. The major outcomes of this study are: (1) median values over 24-h personal and bedroom measurements were <3 μT established by the Italian law as the quality target; (2) geometric mean values over 24-h bedroom measurements were mostly <0.4 μT; (3) seasonal variations did not significantly influence personal and bedroom measurements; (4) the highest average MF levels were mostly found at home during the day and outdoors; (5) no significant differences were found in the median and geometric mean values between personal and bedroom measurements, but were found in the arithmetic mean. PMID:27258295

Association between childhood leukaemia and exposure to power-frequency magnetic fields in Middle Europe.

PubMed

Jirik, Vitezslav; Pekarek, Ludek; Janout, Vladimir; Tomaskova, Hana

2012-10-01

Higher levels of exposure to extremely low-frequency magnetic fields (ELF-MF) are associated with a slightly increased risk of childhood leukaemia. Compared with more-developed Western countries, higher exposure levels are evident in the Czech Republic, probably because of the different types of housing. In light of this, we aimed to examine the association between ELF-MF exposure and childhood leukaemia in the Czech Republic. We conducted a paired case-control study. The cases (children with leukaemia) were age- sex- and permanent residence-matched to controls (children without leukaemia). Although this limited potential bias and confounding, it also limited our number of participants. The matched analyses included 79 case-control pairs. No significant association between ELF-MF exposure and childhood leukaemia was observed for exposures over 0.2 μT (odds ratio [OR]=0.93, confidence interval [CI]=0.45-1.93), 0.3 μT (OR=0.77, CI=0.34-1.75), or 0.4 μT (OR=0.9, CI=0.37-2.22). Despite higher levels of exposure in Middle and Eastern Europe, no indication of an association between ELF-MF exposure and childhood leukaemia was determined. This in contrast to the findings of previous studies conducted in different countries. Copyright © 2012 The Editorial Board of Biomedical and Environmental Sciences. Published by Elsevier B.V. All rights reserved.

Study of interaction of ELF-ULF range (0.1-200 Hz) electromagnetic waves with the earth's crust and the ionosphere in the field of industrial power transmission lines (FENICS experiment)

NASA Astrophysics Data System (ADS)

Zhamaletdinov, A. A.; Shevtsov, A. N.; Velikhov, E. P.; Skorokhodov, A. A.; Kolesnikov, V. E.; Korotkova, T. G.; Ryazantsev, P. A.; Efimov, B. V.; Kolobov, V. V.; Barannik, M. B.; Prokopchuk, P. I.; Selivanov, V. N.; Kopytenko, Yu. A.; Kopytenko, E. A.; Ismagilov, V. S.; Petrishchev, M. S.; Sergushin, P. A.; Tereshchenko, P. E.; Samsonov, B. V.; Birulya, M. A.; Smirnov, M. Yu.; Korja, T.; Yampolski, Yu. M.; Koloskov, A. V.; Baru, N. A.; Poljakov, S. V.; Shchennikov, A. V.; Druzhin, G. I.; Jozwiak, W.; Reda, J.; Shchors, Yu. G.

2015-12-01

This article is devoted to describing the theory, technique, and first experimental results of a control source electromagnetic (CSEM) study of the Earth's crust and ionosphere with the use of two mutually orthogonal industrial transmission lines 109 and 120 km in length in the frame of FENICS (Fennoscandian Electrical Conductivity from Natural and Induction Control Source Soundings) experiment. The main part of the measurements is executed on the territory of the Fennoscandian shield at distances from the first hundreds kilometers up to 856 km from the source with the purpose of the deep electromagnetic sounding of the Earth's crust and upper mantle. According to the results of these studies clarifying the parameters of "normal" (standard) geoelectric section of the lithosphere to a depth of 60-70 km, the anisotropy parameters are evaluated and a geothermal and rheological interpretation in conjunction with the analysis of the seismic data is executed. Furthermore, to study the propagation of ELF-LLF waves (0.1-200 Hz) in an "Earth-Ionosphere" waveguide, the measurements are carried out apart from Fennoscandian shield at distances up to 5600 km from the source (in Ukraine, Spitsbergen, Poland, Kamchatka, and other areas). According to the results of these studies, the experimental estimates of the influence of the ionosphere and of the displacement currents on the propagation of ELF-ULF waves in the upper half-space at the different azimuths generation of the primary field are obtained.

Lion roars and nonoscillatory drift mirror waves in the magnetosheath

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsurutani, B.T.; Smith, E.J.; Anderson, R.R.

1982-08-01

A complete set of ISEE plasma wave, plasma, and field data are used to identify the plasma instability responsible for the generation of extremely low frequency (ELF) electromagnetic lion roars. Lion roars detected close to the magnetopause are generated by the cyclotron instability of anisotropic (T/sup -//sub perpendicular//T/sup -//sub parallel/approx. =1.2) thermal electrons when the local plasma critical energy, E/sub M/ = B/sup 2//8..pi..N, falls to values (E/sub M/ approx.10--30 eV) close to or below the electron thermal energy, 25 eV, as a result of decreases in B. The lion roars are terminated by increases in the ambient magnetic fieldmore » magnitude and consequential increases in E/sub M/ to values greater than 100 eV. Because there are few resonant particles at these high energies, the growth rate decreases by 3 orders of magnitude and measurable growth ceases. The value of the absolute upper limit of the frequency of unstable waves predicted by theory, ..omega../sub max/ = A/sup -/..cap omega../sup -//(A/sup -/+1), is compared with observations. The predictions and observations are found to be in general, but not exact, agreement. Several possible explanations are explored. The quasi-periodic, approx.20-s magnetic and plasma oscillations which cause the variations in E/sub M/ and hence alternately drive the cyclotron waves unstable and then stable are also investigated.« less

Spectral analysis to assess exposure to extremely low frequency magnetic fields in cars.

PubMed

Paniagua, Jesús M; Rufo, Montaña; Jiménez, Antonio; Antolín, Alicia; Barberá, Jorge

2017-04-15

A type of contamination that has been little studied in cars comes from the extremely low frequency (ELF) magnetic fields generated by the vehicle's electrical devices and the magnetized metal in the tyres. The magnetic fields in cars are frequently analysed with broadband meters sensitive to a frequency range above 30Hz. This has the disadvantage that they neither detect the magnetic field of the spinning tyres nor give any information on the spectral components, which makes it impossible to adequately assess exposure. The objective of the present study was to perform spectral analyses of ELF magnetic fields in cars, to identify their frequencies, and to assess exposure based on the ICNIRP regulatory guidelines. To do this, a meter and a spectrum analyser sensitive to magnetic fields in the 5Hz-2kHz frequency range were used. Spectra were acquired for different seats, heights, and speeds, and spatially averaged exposure coefficients were calculated. The results indicated that the main emissions were detected in the 5-100Hz range, where the wheel rotation frequencies and their harmonics are found. The intensity of the rest of the emissions were negligible in comparison. The exposure quotient increases with speed, and is approximately twice as great at foot level as at head level. The magnetic field levels are lower than the reference levels (the maximum represents 3% of the ICNIRP standard), but higher than those found in residential environments and than the cut-off threshold used by the IARC to classify ELF magnetic fields in Group 2B. Copyright © 2017 Elsevier B.V. All rights reserved.

ELF magnetic therapy and oxidative balance.

PubMed

Raggi, Francesco; Vallesi, Giuseppe; Rufini, Stefano; Gizzi, Stefania; Ercolani, Enrico; Rossi, Ruggero

2008-01-01

Knowledge about the relationship between exposure to extremely low-frequency (ELF) EMF and formation (or neutralization) of free radicals in the living cells is limited. Studies performed on animals and plants have shown conflicting effects on the relation between EMF and oxidative stress. Very few experiments have been performed on humans. The present study reports on the effects of an ELF magnetic therapy device (Seqex) on oxidative scale in humans. This device supplies complex magnetic signals with specific choices of frequency, intensity, and shape that are based on Liboff's ion cyclotron resonance hypothesis. Thirty-two healthy volunteers were treated using the Seqex cycle. A quantitative determination of oxidative stress was obtained at three time points by measuring Malondialdehyde (MDA) concentrations in peripheral blood before and after the cycle and one month following completion of the cycle. A highly significant reduction in mean MDA (53.8%, p = 0.0002) was found at the end of the treatment. One month later the mean MDA had again risen, but there was still a significant overall reduction of 15.6% (p = 0.010) compared to original values.

Ionospheric signatures of cusp latitude Pc 3 pulsations

NASA Technical Reports Server (NTRS)

Engebretson, M. J.; Anderson, B. J.; Cahill, L. J., Jr.; Arnoldy, R. L.; Rosenberg, T. J.

1990-01-01

Search coil magnetometer, riometer, photometer, and ELF-VLF receiver data obtained at South Pole Station and McMurdo, Antarctica during selected days in March and April 1986 are compared. Narrow-band magnetic pulsations in the Pc 3 period range are observed simultaneously at both stations in the dayside sector during times of low IMF cone angle, but are considerably stronger at South Pole, which is located at a latitude near the nominal foot point of the dayside cusp/cleft region. Pulsations in auroral light at 427.8 nm wavelength are often observed with magnetic pulsations at South Pole, but such optical pulsations are not observed at McMurdo. The observations suggest that precipitating magnetosheathlike electrons at nominal dayside cleft latitudes are at times modulated with frequencies similar to those of upstream waves. These particles may play an important role, via modification of ionospheric currents and conductivities, in the transmission of upstream wave signals into the magnetosphere and in the generation of dayside high-latitude Pc 3 pulsations.

Rescue of Moribund Chicken Embryos by Extremely Low-Frequency Electric Fields.

PubMed

Cooper, Peter D

Modern living is awash with low-frequency electromagnetic radiation raising concern over health effects, birth defects, and infant cancers especially leukemias. Medical/scientific opinion is ambivalent, especially regarding possible mechanisms of action despite our bodies׳ many electric currents. Are some cancers induced by morphogenetic changes rather than direct mutation? We wished to see if morphogenetic effects of weak, extremely low-frequency electric (ELF) fields in embryonated hen׳s eggs could induce cancers, knowing that such treatment is usually deleterious. We report a pilot study intended to reveal a promising cell source in which to search for cancer cells by established methods and then to check for DNA damage. Stored (5°C for 1-36 days) fresh, fertile hens׳ eggs were incubated (38°C, total five or six days) in presence or absence of a weak ELF oscillating electric field (1-40V/cm, 1-50Hz and two to six days). Separated embryos were assessed for development stage. Storage of untreated eggs (>12 days, 5°C) allows a steady loss of normal embryo formation at 38°C (few viable by 25 days, half-life ~18 days). Surprisingly, incubation in a weak ELF field during the period of declining viability significantly (P: 0.03-0.0001) improved viability and condition of the embryos (new half-life ~21 days), rather than the expected converse. Thus for a few days, the field could keep viable some embryos that would otherwise not have survived. The rescued embryos and their untreated controls seem the most promising place to seek any carcinogenic effects of ELF fields. The nature of the presumed critical component keeping them viable during 5°C storage is at least of equal interest. Copyright © 2016 Elsevier Inc. All rights reserved.

Simulation and Measurement of Through-the-Earth, Extremely Low-Frequency Signals Using Copper-Clad Steel Ground Rods.

PubMed

Damiano, Nicholas William; Yan, Lincan; Whisner, Bruce; Zhou, Chenming

2017-01-01

The underground mining environment can greatly affect radio signal propagation. Understanding how the earth affects signal propagation is a key to evaluating communications systems used during a mine emergency. One type of communication system is through-the-earth, which can utilize extremely low frequencies (ELF). This paper presents the simulation and measurement results of recent National Institute for Occupational Safety and Health (NIOSH) research aimed at investigating current injection at ELF, and in particular, ground contact impedance. Measurements were taken at an outside surface testing location. The results obtained from modeling and measurement are characterized by electrode impedance, and the voltage received between two distant electrodes. This paper concludes with a discussion of design considerations found to affect low-frequency communication systems utilizing ground rods to inject a current into the earth.

Simulation and Measurement of Through-the-Earth, Extremely Low-Frequency Signals Using Copper-Clad Steel Ground Rods

PubMed Central

Damiano, Nicholas William; Yan, Lincan; Whisner, Bruce; Zhou, Chenming

2017-01-01

The underground mining environment can greatly affect radio signal propagation. Understanding how the earth affects signal propagation is a key to evaluating communications systems used during a mine emergency. One type of communication system is through-the-earth, which can utilize extremely low frequencies (ELF). This paper presents the simulation and measurement results of recent National Institute for Occupational Safety and Health (NIOSH) research aimed at investigating current injection at ELF, and in particular, ground contact impedance. Measurements were taken at an outside surface testing location. The results obtained from modeling and measurement are characterized by electrode impedance, and the voltage received between two distant electrodes. This paper concludes with a discussion of design considerations found to affect low-frequency communication systems utilizing ground rods to inject a current into the earth. PMID:29176916

Compilation of 1988 Annual Reports of the Navy ELF (Extremely Low Frequency) Communications System Ecological Monitoring Program. Volume 1

DTIC Science & Technology

1989-08-01

studies. Knowledge of litter biomass production and nutrient content conversely provide one link between the overstory and forest floor components of...system influences on such factors as solar radiation in the understory or soil nutrient status that may be affected by overstory biomass . The...should be sensitive to possible ELF related changes in the canopy of the hardwood stand. I Reduction of foliage biomass or changes in the timing of leaf

Eruption of Permanent Dentition in Rhesus Monkeys Exposed to ELF (extremely Low Frequency) Fields.

DTIC Science & Technology

1983-04-01

Medical Research and Development Commaiid M0096.001-1022 Reviewed by: Approved and Released by: Ashton Graybiel, M.D. Captain W. M. Houk , MC, USN...Chief Scientific Advisor Commanding Officer April 1983 NAVAL AEROSPACE MEDICAL RESEARCH LABORATORY NAVAL AIR S rATION PENSACOLA, FLuRIDA 32508 ii L ½.-- 1...significance level of .05, the calculated a E is .001. 2 V ! -A----;--! PROCEDURE Sixty rhesus monkeys (Macaca mulatta) were introduced into the ELF

Hypothesis: the risk of childhood leukemia is related to combinations of power-frequency and static magnetic fields.

PubMed

Bowman, J D; Thomas, D C; London, S J; Peters, J M

1995-01-01

We present a hypothesis that the risk of childhood leukemia is related to exposure to specific combinations of static and extremely-low-frequency (ELF) magnetic fields. Laboratory data from calcium efflux and diatom mobility experiments were used with the gyromagnetic equation to predict combinations of 60 Hz and static magnetic fields hypothesized to enhance leukemia risk. The laboratory data predicted 19 bands of the static field magnitude with a bandwidth of 9.1 microT that, together with 60 Hz magnetic fields, are expected to have biological activity. We then assessed the association between this exposure metric and childhood leukemia using data from a case-control study in Los Angeles County. ELF and static magnetic fields were measured in the bedrooms of 124 cases determined from a tumor registry and 99 controls drawn from friends and random digit dialing. Among these subjects, 26 cases and 20 controls were exposed to static magnetic fields lying in the predicted bands of biological activity centered at 38.0 microT and 50.6 microT. Although no association was found for childhood leukemia in relation to measured ELF or static magnetic fields alone, an increasing trend of leukemia risk with measured ELF fields was found for subjects within these static field bands (P for trend = 0.041). The odds ratio (OR) was 3.3 [95% confidence interval (CI) = 0.4-30.5] for subjects exposed to static fields within the derived bands and to ELF magnetic field above 0.30 microT (compared to subjects exposed to static fields outside the bands and ELF magnetic fields below 0.07 microT). When the 60 Hz magnetic fields were assessed according to the Wertheimer-Leeper code for wiring configurations, leukemia risks were again greater with the hypothesized exposure conditions (OR = 9.2 for very high current configurations within the static field bands; 95% CI = 1.3-64.6). Although the risk estimates are based on limited magnetic field measurements for a small number of subjects, these findings suggest that the risk of childhood leukemia may be related to the combined effects of the static and ELF magnetic fields. Further tests of the hypothesis are proposed.

Compilation of annual reports of the Navy ELF (Extremely Low Frequency) communications system ecological monitoring program. Volume 1: Tabs A-E

NASA Astrophysics Data System (ADS)

Anderson, M.; Bruhn, J.; Cattelino, P.; Janke, R.; Jurgensen, M.; Mroz, G.; Reed, E. J.; Trettin, C.

1984-07-01

A long-term program of studying ELF electromagnetic influences on ecosystems in northwestern Wisconsin and the Upper Peninsula of Michigan is being conducted. Selection of study sites, monitoring protocols, and analytical methods were initiated in 1982. Data collection was initiated in 1983. Progress is described for studying the terrestrial, aquatic, and wetland ecosystems for the 10 projects comprising the ecological monitoring program. The 10 projects contain Herbaceous Plant Cover and Tree Studies; Litter Decomposition and Microflora; The Effects of Exposing the Slime Mold Physarum polycephalum; Soil Amoeba; Soil and Litter Arthropoda and Earthworm Studies; Biological Studies on Pollinating Insects (Megachilid Bees); Small Vertebrates (Small Mammals and Nesting Birds); Aquatic Ecosystems; Wetland Studies; and Field Studies of Effects of ELF on Migrating Birds.

Pulsed magnetic therapy increases osteogenic differentiation of mesenchymal stem cells only if they are pre-committed.

PubMed

Ferroni, Letizia; Tocco, Ilaria; De Pieri, Andrea; Menarin, Martina; Fermi, Enrico; Piattelli, Adriano; Gardin, Chiara; Zavan, Barbara

2016-05-01

Pulsed electromagnetic field (PEMF) therapy has been documented to be an effective, non-invasive, safe treatment method for a variety of clinical conditions, especially in settings of recalcitrant healing. The underlying mechanisms on the different biological components of tissue regeneration are still to be elucidated. The aim of the present study was to characterize the effects of extremely low frequency (ELF)-PEMFs on commitment of mesenchymal stem cell (MSCs) culture system, through the determination of gene expression pattern and cellular morphology. Human MSCs derived from adipose tissue (ADSCs) were cultured in presence of adipogenic, osteogenic, neural, or glial differentiative medium and basal medium, then exposed to ELF-PEMFs daily stimulation for 21days. Control cultures were performed without ELF-PEMFs stimulation for all cell populations. Effects on commitment were evaluated after 21days of cultures. The results suggested ELF-PEMFs does not influence ADSCs commitment and does not promote adipogenic, osteogenic, neural or glial differentiation. However, ELF-PEMFs treatment on ADSCs cultured in osteogenic differentiative medium markedly increased osteogenesis. We concluded that PEMFs affect the osteogenic differentiation of ADSCs only if they are pre-commitment and that this therapy can be an appropriate candidate for treatment of conditions requiring an acceleration of repairing process. Copyright © 2016 Elsevier Inc. All rights reserved.

Cellular studies and interaction mechanisms of extremely low frequency fields

NASA Astrophysics Data System (ADS)

Liburdy, Robert P.

1995-01-01

Worldwide interest in the biological effects of ELF (extremely low frequency, <1 kHz) electromagnetic fields has grown significantly. Health professionals and government administrators and regulators, scientists and engineers, and, importantly, an increasing number of individuals in the general public are interested in this health issue. The goal of research at the cellular level is to identify cellular responses to ELF fields, to develop a dose threshold for such interactions, and with such information to formulate and test appropriate interaction mechanisms. This review is selective and will discuss the most recent cellular studies directed at these goals which relate to power line, sinusoidal ELF fields. In these studies an interaction site at the cell membrane is by consensus a likely candidate, since changes in ion transport, ligand-receptor events such as antibody binding, and G protein activation have been reported. These changes strongly indicate that signal transduction (ST) can be influenced. Also, ELF fields are reported to influence enzyme activation, gene expression, protein synthesis, and cell proliferation, which are triggered by earlier ST events at the cell membrane. The concept of ELF fields altering early cell membrane events and thereby influencing intracellular cell function via the ST cascade is perhaps the most plausible biological framework currently being investigated for understanding ELF effects on cells. For example, the consequence of an increase due to ELF fields in mitogenesis, the final endpoint of the ST cascade, is an overall increase in the probability of mutagenesis and consequently cancer, according to the Ames epigenetic model of carcinogenesis. Consistent with this epigenetic mechanism and the ST pathway to carcinogenesis is recent evidence that ELF fields can alter breast cancer cell proliferation and can act as a copromoter in vitro. The most important dosimetric question being addressed currently is whether the electric (E) or the magnetic (B) field, or if combinations of static B and time-varying B fields represent an exposure metric for the cell. This question relates directly to understanding fundamental interaction mechanisms and to the development of a rationale for ELF dose threshold guidelines. The weight of experimental evidence indicates that an induced E field according to Faraday's law of induction during magnetic field exposures elicits cellular effects. An E-field-mediated interaction has interesting consequences for microdosimetry at the cellular level and is mechanistically consistent with an interaction at the cell surface, since the E field does not penetrate beyond the cell membrane. Recently, several studies have suggested that an ELF B field by itself or in combination with a static B field may elicit cellular effects. Thus in addition to E-field-mediated effects, other interaction mechanisms as yet not fully understood may operate at the cellular level; this complexity is in contrast to the case for ionizing radiation. In addition to the question of an exposure field metric, the biological state of the target cell is important in ELF interactions. Biological factors such as cell type, cell cycle, cell activation, age of donor animal, passage number of cell line, presence of specific growth/mitogenic factors, temperature, shape, and cell density/packing during exposures have been shown to play a role in mediating ELF interactions with cells. Most recently, reports of single-cell studies usher in a new direction for research that can be termed microbioelectromagnetics. Single-cell digital microscopy introduces a new approach to answer the above questions with potential for real-time microdosimetry and bioeffects limited only by the spatial resolution of state-of-the-art microscopy, which is approximately 0.1 /μm. Digital imaging microscopy should therefore permit the quantitative assessment of spatial and temporal features of ELF field interactions within living single cells.

Initial Results from the Vector Electric Field Investigation on the C/NOFS Satellite

NASA Technical Reports Server (NTRS)

Pfaff, R.; Rowland, D.; Acuna, M.; Le, G.; Farrell, W.; Holzworth, R.; Wilson, G.; Burke, W.; Freudenreich, H.; Bromund, K.;

MEASUREMENT OF SMALL MECHANICAL VIBRATIONS OF BRAIN TISSUE EXPOSED TO EXTREMELY-LOW-FREQUENCY ELECTRIC FIELDS

EPA Science Inventory

Electromagnetic fields can interact with biological tissue both electrically and mechanically. This study investigated the mechanical interaction between brain tissue and an extremely-low-frequency (ELF) electric field by measuring the resultant vibrational amplitude. The exposur...

Exposure of welders and other metal workers to ELF magnetic fields.

PubMed

Skotte, J H; Hjøllund, H I

1997-01-01

This study assessed exposure to extremely low frequency (ELF) magnetic fields of welders and other metal workers and compared exposure from different welding processes. Exposure to ELF magnetic fields was measured for 50 workers selected from a nationwide cohort of metal workers and 15 nonrandomly selected full-time welders in a shipyard. The measurements were carried out with personal exposure meters during 3 days of work for the metal workers and I day of work for the shipyard welders. To record a large dynamic range of ELF magnetic field values, the measurements were carried out with "high/low" pairs of personal exposure meters. Additional measurements of static magnetic fields at fixed positions close to welding installations were done with a Hall-effect fluxmeter. The total time of measurement was 1273 hours. The metal workers reported welding activity for 5.8% of the time, and the median of the work-period mean exposure to ELF magnetic fields was 0.18 microT. DC metal inert or active gas welding (MIG/MAG) was used 80% of the time for welding, and AC manual metal arc welding (MMA) was used 10% of the time. The shipyard welders reported welding activity for 56% of the time, and the median and maximum of the workday mean exposure to ELF magnetic fields was 4.70 and 27.5 microT, respectively. For full-shift welders the average workday mean was 21.2 microT for MMA welders and 2.3 microT for MIG/MAG welders. The average exposure during the effective time of welding was estimated to be 65 microT for the MMA welding process and 7 microT for the MIG/MAG welding process. The time of exposure above 1 microT was found to be a useful measure of the effective time of welding. Large differences in exposure to ELF magnetic fields were found between different groups of welders, depending on the welding process and effective time of welding. MMA (AC) welding caused roughly 10 times higher exposure to ELF magnetic fields compared with MIG/MAG (DC) welding. The measurements of static fields suggest that the combined exposure to static and ELF fields of MIG/MAG (DC) welders and the exposure to ELF fields of MMA (AC) welders are roughly of the same level.

Numerical modeling of subsurface communication

NASA Astrophysics Data System (ADS)

Burke, G. J.; Dease, C. G.; Didwall, E. M.; Lytle, R. J.

1985-02-01

Techniques are described for numerical modeling of through-the-Earth communication. The basic problem considered is evaluation of the field at a surface or airborne station due to an antenna buried in the Earth. Equations are given for the field of a point source in a homogeneous or stratified earth. These expressions involve infinite integrals over wave number, sometimes known as Sommerfield integrals. Numerical techniques used for evaluating these integrals are outlined. The problem of determining the current on a real antenna in the Earth, including the effect of insulation, is considered. Results are included for the fields of a point source in homogeneous and stratified earths and the field of a finite insulated dipole. The results are for electromagnetic propagation in the ELF-VLF range, but the codes also can address propagation problems at higher frequencies.

Absence of DNA damage after 60-Hz electromagnetic field exposure combined with ionizing radiation, hydrogen peroxide, or c-Myc overexpression.

PubMed

Jin, Yeung Bae; Choi, Seo-Hyun; Lee, Jae Seon; Kim, Jae-Kyung; Lee, Ju-Woon; Hong, Seung-Cheol; Myung, Sung Ho; Lee, Yun-Sil

2014-03-01

The principal objective of this study was to assess the DNA damage in a normal cell line system after exposure to 60 Hz of extremely low frequency magnetic field (ELF-MF) and particularly in combination with various external factors, via comet assays. NIH3T3 mouse fibroblast cells, WI-38 human lung fibroblast cells, L132 human lung epithelial cells, and MCF10A human mammary gland epithelial cells were exposed for 4 or 16 h to a 60-Hz, 1 mT uniform magnetic field in the presence or absence of ionizing radiation (IR, 1 Gy), H(2)O(2) (50 μM), or c-Myc oncogenic activation. The results obtained showed no significant differences between the cells exposed to ELF-MF alone and the unexposed cells. Moreover, no synergistic or additive effects were observed after 4 or 16 h of pre-exposure to 1 mT ELF-MF or simultaneous exposure to ELF-MF combined with IR, H(2)O(2), or c-Myc activation.

A Touch Sensing Technique Using the Effects of Extremely Low Frequency Fields on the Human Body.

PubMed

Elfekey, Hatem; Bastawrous, Hany Ayad; Okamoto, Shogo

2016-12-02

Touch sensing is a fundamental approach in human-to-machine interfaces, and is currently under widespread use. Many current applications use active touch sensing technologies. Passive touch sensing technologies are, however, more adequate to implement low power or energy harvesting touch sensing interfaces. This paper presents a passive touch sensing technique based on the fact that the human body is affected by the surrounding extremely low frequency (ELF) electromagnetic fields, such as those of AC power lines. These external ELF fields induce electric potentials on the human body-because human tissues exhibit some conductivity at these frequencies-resulting in what is called AC hum. We therefore propose a passive touch sensing system that detects this hum noise when a human touch occurs, thus distinguishing between touch and non-touch events. The effectiveness of the proposed technique is validated by designing and implementing a flexible touch sensing keyboard.

Affective response to 5 microT ELF magnetic field-induced physiological changes.

PubMed

Stevens, Paul

2007-02-01

Research into effects of weak magnetic fields (MFs) at biologically relevant frequencies has produced ambiguous results. Although they do affect human physiology and behaviour, the direction of effects is inconsistent, with a range of complex and unrelated behaviours being susceptible. A possible explanation is that these effects, rather than being directly caused, are instead related to changes in affective state. A previous study showed that MFs altered the affective content of concurrent perceptions, but it was unclear whether the emotional response was direct or indirect. Here it is shown that exposure to a 0-5 microT MF (DC-offset sinudsoidal wave form) within EEG alpha-band frequencies (8-12 Hz), results in a reported change in emotional state. This relates to a decrease global field power but lacks the frontal alpha-asymmetry that would physiologically indicate a directly induced emotional state, suggesting that participant experiences are due to an interpretation of the effects of MF exposure.

Experimental study of global electromagnetic resonances of the Earth-ionosphere cavity in high latitudes (Novaya Zemlya Island and settlement Tiksi)

NASA Astrophysics Data System (ADS)

Auyrov, D. B.; Khaptanov, V. B.; Bashkuev, Yu. B.; Buyanova, D. G.

2017-11-01

The results of measurements of the horizontal electric field Eh components of the natural electromagnetic field of the Earth (Schumann resonances, SR) in the extreme low frequency (ELF) radio wave bands on Novaya Zemlya Island and settlement Tiksi are considered. In the electromagnetic clean arctic region on August 2016 (the Bay of Blagopoluchiya (75°41'59″ N; 63° 42' 36″ E)) the global electromagnetic resonances (SR) of the Earth-ionosphere cavity up to the 7th and 8th resonant peaks in spectra are identified. Calculated and experimental values of the peak frequencies fn and Qnfactors of the cavity "Earth-ionosphere" are presented. On the spectra of records received on July, 2015 also in high latitudes near settlement Tiksi (71°35'3″ N; 128°46'4″ E) we work with the same measuring equipment and observed the 4th and 5th SR resonances. Diurnal variations of basic parameters of Schumann resonances are investigated.

Number of transients/Q-bursts in ELF-band as possible criterion for global thunderstorm activity estimation.

NASA Astrophysics Data System (ADS)

Ondraskova, Adriena; Sevcik, Sebastian

2015-04-01

Schumann resonances (SR) are resonant electromagnetic oscillations in extremely low frequency band (ELF, 3 Hz - 3 kHz), which arise in the Earth-ionosphere cavity due to lightning activity in planetary range. The time records in the ELF-band consist of background signals and ELF transients/Q-bursts superimposed on the background exceeding it by a factor of 5 - 10. The former are produced by the common worldwide thunderstorm activity (100 - 150 events per second), the latter origin from individual intense distant lightning discharges (100 - 120 powerful strokes per hour). A Q-burst is produced by a combination of direct and antipodal pulses and the decisive factor for its shape follows from the source-to-observer distance (SOD). Diurnal/seasonal variations of global thunderstorm activity can be deduced from spectral amplitudes of SR modes. Here we focus on diurnal/seasonal variations of the number of ELF-transients assuming that it is another way of lightning activity estimation. To search for transients, our own code was applied to the SR vertical electric component measured in October 2004 - December 2008 at the Astronomical and Geophysical Observatory of FMPI CU, Slovakia. Limits (min-max) for the width of primary spike, time difference between primary and secondary spike and the amplitude of the spike were chosen as criteria for the identification of the burst. Cumulative spectral amplitude of the first three SR modes compared with number of ELF-transients in monthly averaged diurnal variations quite successfully confirmed, that the number of transients can be a suitable criterion for the quantification of global lightning activity.

Chronic exposure to 50Hz magnetic fields causes a significant weakening of antioxidant defence systems in aged rat brain.

PubMed

Falone, Stefano; Mirabilio, Alessandro; Carbone, Maria Cristina; Zimmitti, Vincenzo; Di Loreto, Silvia; Mariggiò, Maria Addolorata; Mancinelli, Rosa; Di Ilio, Carmine; Amicarelli, Fernanda

2008-01-01

Several studies suggest that extremely low-frequency magnetic fields (ELF-MFs) may enhance the free radical endogenous production. It is also well known that one of the unavoidable consequences of ageing is an overall oxidative stress-based decline in several physiological functions and in the general resistance to stressors. On the basis of these assumptions, the aim of this study was to establish whether the ageing process can increase susceptibility towards widely present ELF-MF-mediated pro-oxidative challenges. To this end, female Sprague-Dawley rats were continuously exposed to a sinusoidal 50 Hz, 0.1 mT magnetic field for 10 days. Treatment-induced changes in the major antioxidant protection systems and in the neurotrophic support were investigated, as a function of the age of the subjects. All analyses were performed in brain cortices, due to the high susceptibility of neuronal cells to oxidative injury. Our results indicated that ELF-MF exposure significantly affects anti-oxidative capability, both in young and aged animals, although in opposite ways. Indeed, exposed young individuals enhanced their neurotrophic signalling and anti-oxidative enzymatic defence against a possible ELF-MF-mediated increase in oxygen radical species. In contrast, aged subjects were not capable of increasing their defences in response to ELF-MF treatment but, on the contrary, they underwent a significant decrease in the major antioxidant enzymatic activities. In conclusion, our data seem to suggest that the exposure to ELF-MFs may act as a risk factor for the occurrence of oxidative stress-based nervous system pathologies associated with ageing.

ELF/VLF/LF Radio Propagation and Systems Aspects (La Propagation des Ondes Radio ELF/VLF/LF et les Aspects Systemes)

DTIC Science & Technology

1993-05-01

limitation of the software package would not allow DATE/I’ME FREQUENCY (kHz) the program to run over 2359 to 0001 UT. This was 18.1 19.0 21.4 24.0...Capability (LWPC), software package devel- oped at NOSC (FERGUSON et al 1989) and adapted by us to the Macintosh personal computer. We find that this... software works very well. Our investigations are to I evaluate and devise geophysical models to be used with . LWPC in assessing VLF communications and

Excitation of earth-ionosphere waveguide in the ELF and lower VLF bands by modulated ionospheric current. Technical report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Field, E.C.; Bloom, R.M.

1993-05-21

In this report the authors use the principal of reciprocity in conjunction with a full-wave propagation code to calculate ground-level fields excited by ionospheric currents modulated at frequencies between 50 and 100 Hz with HF heaters. Their results show the dependence on source orientation, altitude, and dimension and therefore pertain to experiments using the HIPAS or HAARP ionospheric heaters. In the end-fire mode, the waveguide excitation efficiency of an ELF HED in the ionosphere is up to 20 dB greater than for a ground-based antenna, provided its altitude does not exceed 80-to-90 km. The highest efficiency occurs for a sourcemore » altitude of around 70 km; if that altitude is raised to 100 km, the efficiency drops by about 20 dB in the day and 10 dB at night. That efficiency does not account for the greater conductivity modulation that might be achieved at altitudes greater than 70 km, however. The trade-off between the altitude dependencies of the excitation efficiency and maximum achievable modulation depends on the ERP of the HF heater, the optimum altitude increasing with increasing ERP. For HIPAS the best modulation altitude is around 70 km, whereas for HAARP there might be marginal value in modulating at attitudes as high as 100 Km. Ionospheric modification, Ionospheric currents, Ionospheric heating.« less

Nonlinear plasma experiments in geospace with gigawatts of RF power at HAARP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheerin, J. P., E-mail: jsheerin@emich.edu; Cohen, Morris B., E-mail: mcohen@gatech.edu

2015-12-10

The ionosphere is the ionized uppermost layer of our atmosphere (from 70 – 500 km altitude) where free electron densities yield peak critical frequencies in the HF (3 – 30 MHz) range. The ionosphere thus provides a quiescent plasma target, stable on timescales of minutes, for a whole host of active plasma experiments. High power RF experiments on ionospheric plasma conducted in the U.S. have been reported since 1970. The largest HF transmitter built to date is the HAARP phased-array HF transmitter near Gakona, Alaska which can deliver up to 3.6 Gigawatts (ERP) of CW RF power in the range of 2.8more » – 10 MHz to the ionosphere with microsecond pointing, power modulation, and frequency agility. With an ionospheric background thermal energy in the range of only 0.1 eV, this amount of power gives access to the highest regimes of the nonlinearity (RF intensity to thermal pressure) ratio. HAARP’s unique features have enabled the conduct of a number of unique nonlinear plasma experiments in the interaction region of overdense ionospheric plasma including generation of artificial aurorae, artificial ionization layers, VLF wave-particle interactions in the magnetosphere, parametric instabilities, stimulated electromagnetic emissions (SEE), strong Langmuir turbulence (SLT) and suprathermal electron acceleration. Diagnostics include the Modular UHF Ionospheric Radar (MUIR) sited at HAARP, the SuperDARN-Kodiak HF radar, spacecraft radio beacons, HF receivers to record stimulated electromagnetic emissions (SEE) and telescopes and cameras for optical emissions. We report on short timescale ponderomotive overshoot effects, artificial field-aligned irregularities (AFAI), the aspect angle dependence of the intensity of the HF-enhanced plasma line, and production of suprathermal electrons. One of the primary missions of HAARP, has been the generation of ELF (300 – 3000 Hz) and VLF (3 – 30 kHz) radio waves which are guided to global distances in the Earth-ionosphere waveguide. We review recent efforts to improve the efficiency of the generation ELF/VLF and develop alternative mechanisms that do not require a natural ionospheric current. Applications include the controlled study of ionospheric irregularities affecting spacecraft communication and navigation systems.« less

Nonlinear plasma experiments in geospace with gigawatts of RF power at HAARP

NASA Astrophysics Data System (ADS)

Sheerin, J. P.; Cohen, Morris B.

2015-12-01

The ionosphere is the ionized uppermost layer of our atmosphere (from 70 - 500 km altitude) where free electron densities yield peak critical frequencies in the HF (3 - 30 MHz) range. The ionosphere thus provides a quiescent plasma target, stable on timescales of minutes, for a whole host of active plasma experiments. High power RF experiments on ionospheric plasma conducted in the U.S. have been reported since 1970. The largest HF transmitter built to date is the HAARP phased-array HF transmitter near Gakona, Alaska which can deliver up to 3.6 Gigawatts (ERP) of CW RF power in the range of 2.8 - 10 MHz to the ionosphere with microsecond pointing, power modulation, and frequency agility. With an ionospheric background thermal energy in the range of only 0.1 eV, this amount of power gives access to the highest regimes of the nonlinearity (RF intensity to thermal pressure) ratio. HAARP's unique features have enabled the conduct of a number of unique nonlinear plasma experiments in the interaction region of overdense ionospheric plasma including generation of artificial aurorae, artificial ionization layers, VLF wave-particle interactions in the magnetosphere, parametric instabilities, stimulated electromagnetic emissions (SEE), strong Langmuir turbulence (SLT) and suprathermal electron acceleration. Diagnostics include the Modular UHF Ionospheric Radar (MUIR) sited at HAARP, the SuperDARN-Kodiak HF radar, spacecraft radio beacons, HF receivers to record stimulated electromagnetic emissions (SEE) and telescopes and cameras for optical emissions. We report on short timescale ponderomotive overshoot effects, artificial field-aligned irregularities (AFAI), the aspect angle dependence of the intensity of the HF-enhanced plasma line, and production of suprathermal electrons. One of the primary missions of HAARP, has been the generation of ELF (300 - 3000 Hz) and VLF (3 - 30 kHz) radio waves which are guided to global distances in the Earth-ionosphere waveguide. We review recent efforts to improve the efficiency of the generation ELF/VLF and develop alternative mechanisms that do not require a natural ionospheric current. Applications include the controlled study of ionospheric irregularities affecting spacecraft communication and navigation systems.

Exposure to an extremely low-frequency electromagnetic field only slightly modifies the proteome of Chromobacterium violaceumATCC 12472.

PubMed

Baraúna, Rafael A; Santos, Agenor V; Graças, Diego A; Santos, Daniel M; Ghilardi, Rubens; Pimenta, Adriano M C; Carepo, Marta S P; Schneider, Maria P C; Silva, Artur

2015-05-01

Several studies of the physiological responses of different organisms exposed to extremely low-frequency electromagnetic fields (ELF-EMF) have been described. In this work, we report the minimal effects of in situ exposure to ELF-EMF on the global protein expression of Chromobacterium violaceum using a gel-based proteomic approach. The protein expression profile was only slightly altered, with five differentially expressed proteins detected in the exposed cultures; two of these proteins (DNA-binding stress protein, Dps, and alcohol dehydrogenase) were identified by MS/MS. The enhanced expression of Dps possibly helped to prevent physical damage to DNA. Although small, the changes in protein expression observed here were probably beneficial in helping the bacteria to adapt to the stress generated by the electromagnetic field.

Possible Mechanism of Action of the Electromagnetic Fields of Ultralow Frequency on G-protein

NASA Astrophysics Data System (ADS)

Nava, J. J. Godina; Segura, M. A. Rodríguez; García, M. N. Jiménez; Cadena, M. S. Reyes

2008-08-01

Based in several clinical achievements and mathematical simulation of the immune sytem, previously studied, permit us to establish that a possible Mechanism of Action of ultralow frequency Electromagnetic Fields (ELF) is on G-protein as it has been proposed in specialized literature.

Numerical modeling of subsurface communication, revision 1

NASA Astrophysics Data System (ADS)

Burke, G. J.; Dease, C. G.; Didwall, E. M.; Lytle, R. J.

1985-08-01

Techniques are described for numerical modeling of through-the-Earth communication. The basic problem considered is evaluation of the field at a surface or airborne station due to an antenna buried in the earth. Equations are given for the field of a point source in a homogeneous or stratified Earth. These expressions involve infinite integrals over wave number, sometimes known as Sommerfeld integrals. Numerical techniques used for evaluating these integrals are outlined. The problem of determining the current on a real antenna in the Earth, including the effect of insulation, is considered. Results are included for the fields of a point source in homogeneous and stratified earths and the field of a finite insulated dipole. The results are for electromagnetic propagation in the ELF-VLF range, but the codes also can address propagation problems at higher frequencies.

Field-aligned currents, convection electric fields, and ULF-ELF waves in the cusp

NASA Technical Reports Server (NTRS)

Saflekos, N. A.; Potemra, T. A.; Kintner, P. M., Jr.; Green, J. L.

1979-01-01

Nearly simultaneous observations from the Triad and Hawkeye satellites over the Southern Hemisphere, at low altitudes near the noon meridian and close to the usual polar cusp latitudes, show that in and near the polar cusp there exist several relationships between field-aligned currents (FACs), convection electric fields, ULF-ELF magnetic noise, broadband electrostatic noise and interplanetary magnetic fields. The most important findings are (1) the FACs directed into the ionosphere in the noon-to-dusk local time sector and directed away from the ionosphere in the noon-to-dawn local time sector and identified as region-1 permanent FACs (Iijima and Potemra, 1976a) and are located equatorward of the regions of antisunward (westward) convection; (2) the observations are consistent with a two-cell convection pattern symmetric in one case (throat positioned at noon) and asymmetric in another (throat located in a sector on the forenoon side in juxtaposition to the region of strong convection on the afternoon side); and (3) fine-structure FACs are responsible for the generation of ULF-ELF noise in the polar cusp.

Residential exposure from extremely low frequency electromagnetic field (ELF EMF) radiation

NASA Astrophysics Data System (ADS)

Parthasarathy, Shamesh Raj; Tukimin, Roha

2018-01-01

ELF EMF radiation have received considerable attention as a potential threat to the safety and health of people living in the vicinity of high voltage transmission lines, electric distribution substations, power stations and even in close proximity to electronics and electrical household appliances. The paper highlights the study on the ELF EMF safety assessment performed at residences comprising of an owner-occupied house, a completed vacant house and an under construction condominium. The objectives of this study were to determine the ELF EMF radiation exposure level from the high voltage transmission line, electric distribution substation, power station and electrical household appliances in the residences, and to assess the potential exposure received by the occupants at the assessed locations. The results were logged in the electric and magnetic field strength with the units of volt per meter (V/m) and miliGauss (mG) respectively. The instrument setup and measurement protocols during the assessment were adopted from standard measurement method and procedures stipulated under the Institute of Electrical and Electronics Engineers (IEEE) Standard. The results were compared with the standards recommended in the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines.

Improved Mitochondrial and Methylglyoxal-Related Metabolisms Support Hyperproliferation Induced by 50 Hz Magnetic Field in Neuroblastoma Cells.

PubMed

Falone, Stefano; Santini, Silvano; di Loreto, Silvia; Cordone, Valeria; Grannonico, Marta; Cesare, Patrizia; Cacchio, Marisa; Amicarelli, Fernanda

2016-09-01

Extremely low frequency magnetic fields (ELF-MF) are common environmental agents that are suspected to promote later stages of tumorigenesis, especially in brain-derived malignancies. Even though ELF magnetic fields have been previously linked to increased proliferation in neuroblastoma cells, no previous work has studied whether ELF-MF exposure may change key biomolecular features, such as anti-glycative defence and energy re-programming, both of which are currently considered as crucial factors involved in the phenotype and progression of many malignancies. Our study investigated whether the hyperproliferation that is induced in SH-SY5Y human neuroblastoma cells by a 50 Hz, 1 mT ELF magnetic field is supported by an improved defense towards methylglyoxal (MG), which is an endogenous cancer-static and glycating α-oxoaldehyde, and by rewiring of energy metabolism. Our findings show that not only the ELF magnetic field interfered with the biology of neuron-derived malignant cells, by de-differentiating further the cellular phenotype and by increasing the proliferative activity, but also triggered cytoprotective mechanisms through the enhancement of the defense against MG, along with a more efficient management of metabolic energy, presumably to support the rapid cell outgrowth. Intriguingly, we also revealed that the MF-induced bioeffects took place after an initial imbalance of the cellular homeostasis, which most likely created a transient unstable milieu. The biochemical pathways and molecular targets revealed in this research could be exploited for future approaches aimed at limiting or suppressing the deleterious effects of ELF magnetic fields. J. Cell. Physiol. 231: 2014-2025, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

On precursory ULF/ELF electromagnetic signatures for the Kobe earthquake on April 12, 2013

NASA Astrophysics Data System (ADS)

Schekotov, A.; Izutsu, J.; Hayakawa, M.

2015-12-01

After the 2011 Tohoku earthquake (EQ), there have been numerous aftershocks in the eastern and Pacific Ocean of Japan, but EQs are still rare in the western part of Japan. In this situation a relatively large (magnitude (M) ∼ 6) EQ happened on April 12 (UT), 2013 at a place close to the 1995 Kobe EQ (M ∼ 7), so we have tried to find whether there existed any electromagnetic precursors to this EQ. Two precursory signatures are detected: one is the depression of ULF (ultra-low-frequency, 0.01-0.02 Hz) geomagnetic variations on April 9, and the second is wideband ELF (extremely low frequency) electromagnetic radiation on April 11. These results for the 2013 Kobe EQ are compared with the corresponding results for the former 1995 Kobe EQ.

Exposure to an extremely low-frequency electromagnetic field only slightly modifies the proteome of Chromobacterium violaceumATCC 12472

PubMed Central

Baraúna, Rafael A.; Santos, Agenor V.; Graças, Diego A.; Santos, Daniel M.; Ghilardi, Rubens; Pimenta, Adriano M. C.; Carepo, Marta S. P.; Schneider, Maria P.C.; Silva, Artur

2015-01-01

Several studies of the physiological responses of different organisms exposed to extremely low-frequency electromagnetic fields (ELF-EMF) have been described. In this work, we report the minimal effects of in situ exposure to ELF-EMF on the global protein expression of Chromobacterium violaceum using a gel-based proteomic approach. The protein expression profile was only slightly altered, with five differentially expressed proteins detected in the exposed cultures; two of these proteins (DNA-binding stress protein, Dps, and alcohol dehydrogenase) were identified by MS/MS. The enhanced expression of Dps possibly helped to prevent physical damage to DNA. Although small, the changes in protein expression observed here were probably beneficial in helping the bacteria to adapt to the stress generated by the electromagnetic field. PMID:26273227

The Use of Signal-Transduction and Metabolic Pathways to Predict Human Disease Targets from Electric and Magnetic Fields Using in vitro Data in Human Cell Lines

PubMed Central

Parham, Fred; Portier, Christopher J.; Chang, Xiaoqing; Mevissen, Meike

2016-01-01

Using in vitro data in human cell lines, several research groups have investigated changes in gene expression in cellular systems following exposure to extremely low frequency (ELF) and radiofrequency (RF) electromagnetic fields (EMF). For ELF EMF, we obtained five studies with complete microarray data and three studies with only lists of significantly altered genes. Likewise, for RF EMF, we obtained 13 complete microarray datasets and 5 limited datasets. Plausible linkages between exposure to ELF and RF EMF and human diseases were identified using a three-step process: (a) linking genes associated with classes of human diseases to molecular pathways, (b) linking pathways to ELF and RF EMF microarray data, and (c) identifying associations between human disease and EMF exposures where the pathways are significantly similar. A total of 60 pathways were associated with human diseases, mostly focused on basic cellular functions like JAK–STAT signaling or metabolic functions like xenobiotic metabolism by cytochrome P450 enzymes. ELF EMF datasets were sporadically linked to human diseases, but no clear pattern emerged. Individual datasets showed some linkage to cancer, chemical dependency, metabolic disorders, and neurological disorders. RF EMF datasets were not strongly linked to any disorders but strongly linked to changes in several pathways. Based on these analyses, the most promising area for further research would be to focus on EMF and neurological function and disorders. PMID:27656641

Apoptosis selectively induced in BEL-7402 cells by folic acid-modified magnetic nanoparticles combined with 100 Hz magnetic field

PubMed Central

Wen, Jian; Jiang, Shulian; Chen, Zhiqiang; Zhao, Wei; Yi, Yongxiang; Yang, Ruili; Chen, Baoan

2014-01-01

Objective To explore the effect of folic acid-modified magnetic nanoparticles (FA-MNPs) combined with a 100 Hz extremely low-frequency electromagnetic field (ELF-EMF) on the apoptosis of liver cancer BEL-7402 cells. Materials and methods MNPs (20 nm) were prepared by coprecipitation, and then folic acid was coated onto MNPs to prepare FA-MNPs. BEL-7402 cells and HL7702 cells were selected as liver cancer cells and normal liver cells, respectively. The ELF-EMF was generated from a solenoid coil. Cellular uptake of NPs was determined by inductively coupled plasma atomic emission spectroscopy. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to evaluate cell inhibition. Apoptosis was analyzed by flow cytometry. Statistical analyses were performed using two-way analysis of variance. Results FA-MNPs combined with a 100 Hz magnetic field significantly inhibited cell proliferation and induced higher apoptosis compared to either the ELF-EMF alone or FA-MNPs alone. FA-MNPs showed a better apoptosis effect and higher iron uptake in BEL-7402 cells compared to in HL7702 cells. On the basis of the ELF-EMF, higher doses of FA-MNPs brought higher apoptosis and higher iron uptake in either BEL-7402 cells or HL7702 cells. Conclusion These results suggest that FA-MNPs may induce apoptosis in a cellular iron uptake-dependent manner when combined with an ELF-EMF in BEL-7402 cells. PMID:24790442

Extremely low-frequency magnetic fields of transformers and possible biological and health effects.

PubMed

Sirav, Bahriye; Sezgin, Gaye; Seyhan, Nesrin

2014-12-01

Physiological processes in organisms can be influenced by extremely low-frequency (ELF) electromagnetic energy. Biological effect studies have great importance; as well as measurement studies since they provide information on the real exposure situations. In this study, the leakage magnetic fields around a transformer were measured in an apartment building in Küçükçekmece, Istanbul, and the measurement results were evaluated with respect to the international exposure standards. The transformer station was on the bottom floor of a three-floor building. It was found that people living and working in the building were exposed to ELF magnetic fields higher than the threshold magnetic field value of the International Agency for Research on Cancer (IARC). Many people living in this building reported health complaints such as immunological problems of their children. There were child-workers working in the textile factories located in the building. Safe distances or areas for these people should be recommended. Protective measures could be implemented to minimize these exposures. Further residential exposure studies are needed to demonstrate the exposure levels of ELF magnetic fields. Precautions should, therefore, be taken either to reduce leakage or minimize the exposed fields. Shielding techniques should be used to minimize the leakage magnetic fields in such cases.

Human health effects of EMFs: The cost of doing nothing

NASA Astrophysics Data System (ADS)

Carpenter MD, David O.

2010-04-01

Everyone is exposed to electromagnetic fields (EMFs) from electricity (extremely low frequency, ELF), communication frequencies and wireless devices (radiofrequency, RF), as well as naturally occurring EMFs. Concern of health hazards from EMFs has increased as the use of mobile phones and other wireless devices has grown in all segments of the population, especially children. While there has been strong evidence for an association between leukemia and residential or occupational exposure to ELF EMFs for many years, the standards in existence are not sufficiently stringent to protect from an increased risk of cancer. ELF EMFs also increase risk of at least two types of neurodegenerative diseases. For RF EMFs, standards are set at levels designed to avoid tissue heating, in spite of many reports of biological effects at intensities too low to cause significant heating. Recent evidence demonstrates elevations in risk of brain cancer and acoustic neuroma only on the side of the head where individuals used their mobile phone. Individuals who begin exposure at younger ages are more vulnerable. These data indicate that the existing standards for radiofrequency exposure are not adequate. While there are many unanswered questions, the cost of doing nothing may result in an increasing number of people, many of them young, developing these diseases.

Quantum mechanical model for the anticarcinogenic effect of extremely-low-frequency electromagnetic fields on early chemical hepatocarcinogenesis

NASA Astrophysics Data System (ADS)

Godina-Nava, Juan José; Torres-Vega, Gabino; López-Riquelme, Germán Octavio; López-Sandoval, Eduardo; Samana, Arturo Rodolfo; García Velasco, Fermín; Hernández-Aguilar, Claudia; Domínguez-Pacheco, Arturo

2017-02-01

Using the conventional Haberkorn approach, it is evaluated the recombination of the radical pair (RP) singlet spin state to study theoretically the cytoprotective effect of an extremely-low-frequency electromagnetic field (ELF-EMF) on early stages of hepatic cancer chemically induced in rats. The proposal is that ELF-EMF modulates the interconversion rate of singlet and triplet spin states of the RP populations modifying the products from the metabolization of carcinogens. Previously, we found that the daily treatment with ELF-EMF 120 Hz inhibited the number and area of preneoplastic lesions in chemical carcinogenesis. The singlet spin population is evaluated diagonalizing the spin density matrix through the Lanczos method in a radical pair mechanism (RPM). Using four values of the interchange energy, we have studied the variations over the singlet population. The low magnetic field effect as a test of the influence over the enzymatic chemical reaction is evaluated calculating the quantum yield. Through a bootstrap technique the range is found for the singlet decay rate for the process. Applying the quantum measurements concept, we addressed the impact toward hepatic cells. The result contributes to improving our understanding of the chemical carcinogenesis process affected by charged particles that damage the DNA.

Compilation of 1990 annual reports of the Navy ELF communications system ecological monitoring program. Volume 3: Tabs G thru I

NASA Astrophysics Data System (ADS)

Zapotosky, J. E.

1991-08-01

This portion of the report includes monitoring of and data for bird species and communities, aquatic ecosystem and a listing of technical reports. Effects of extremely-low-frequency electromagnetic fields on most aspects of a bird species' life history are poorly understood. This investigation was designed to isolate effects of EM fields produced by ELF antenna systems on bird species breeding in or migrating through Wisconsin and Michigan. Specifically, we seek to determine if bird species richness and abundance differ between areas that are close to the antenna and those that are far enough away to be unaffected by the antenna. The goal of the aquatic ecosystems portion of the project is to determine the effects of low-level, long-term, electromagnetic radiation on the biota of streams. This electromagnetic radiation will be derived from the U.S. Navy's extremely low frequency submarine communication system (ELF) located in the upper peninsula of Michigan. The specific ecosystem being studied is the Ford River, a fourth order stream that arises in northern Dickinson and southern Marquette Counties and enters the Michigan portion of Green Bay south of Escanaba, Michigan. Detailed ecological sample and analyses are being conducted simutaneously at two sites.

Effects of Microwave Radiation on Neuronal Activity

DTIC Science & Technology

1991-10-01

salivary glands and human cultured cells to extremely low- frequency (ELF) EMF alters patterns of polypeptide synthesis (18,19). The effects displayed...at 16 Hz. Continuous exposure to radio- frequency radiation for 4 consecutive days led to the development of a cell number density gradient. The...RADIATION ON NEURONAL ACTIVITY SUMMARY The effects of radiofrequency radiation on rat hippocampal fetal neurons were examined. Carrier frequencies of 300 to

Effects of short term and long term Extremely Low Frequency Magnetic Field on depressive disorder in mice: Involvement of nitric oxide pathway.

PubMed

Madjid Ansari, Alireza; Farzampour, Shahrokh; Sadr, Ali; Shekarchi, Babak; Majidzadeh-A, Keivan

2016-02-01

Previous reports on the possible effects of Extremely Low Frequency Magnetic Fields (ELF MF) on mood have been paradoxical in different settings while no study has yet been conducted on animal behavior. In addition, it was shown that ELF MF exposure makes an increase in brain nitric oxide level. Therefore, in the current study, we aimed to assess the possible effect(s) of ELF MF exposure on mice Forced Swimming Test (FST) and evaluate the probable role of the increased level of nitric oxide in the observed behavior. Male adult mice NMRI were recruited to investigate the short term and long term ELF MF exposure (0.5 mT and 50 Hz, single 2h and 2 weeks 2h a day). Locomotor behavior was assessed by using open-field test (OFT) followed by FST to evaluate the immobility time. Accordingly, NΩ-nitro-l-arginine methyl ester 30 mg/kg was used to exert anti-depressant like effect. According to the results, short term exposure did not alter the immobility time, whereas long term exposure significantly reduces immobility time (p<0.01). However, it was revealed that the locomotion did not differ among all experimental groups. Short term exposure reversed the anti-depressant like effect resulting from 30 mg/kg of NΩ-nitro-l-arginine methyl ester (p<0.01). It has been concluded that long term exposure could alter the depressive disorder in mice, whereas short term exposure has no significant effect. Also, reversing the anti-depressant activity of L-NAME indicates a probable increase in the brain nitric oxide. Copyright © 2016 Elsevier Inc. All rights reserved.

Detection of Ionospheric Alfven Resonator Signatures Onboard C/NOFS: Implications for IRI Modeling

NASA Technical Reports Server (NTRS)

Simoes, F.; Klenzing, J.; Ivanov, S.; Pfaff, R.; Rowland, D.; Bilitza, D.

2011-01-01

The 2008-2009 long-lasting solar minimum activity has been the one of its kind since the dawn of space age, offering exceptional conditions for investigating space weather in the near-Earth environment. First ever detection of Ionospheric Alfven Resonator (IAR) signatures in orbit offers new means for investigating ionospheric electrodynamics, namely MHD (MagnetoHydroDynamics) wave propagation, aeronomy processes, ionospheric dynamics, and Sun-Earth connection mechanisms at a local scale. Local and global plasma density heterogeneities in the ionosphere and magnetosphere allow for formation of waveguides and resonators where magnetosonic and shear Alfven waves propagate. The ionospheric magnetosonic waveguide results from complete magnetosonic wave reflection about the ionospheric F-region peak, where the Alfven index of refraction presents a maximum. MHD waves can also be partially trapped in the vertical direction between the lower boundary of the ionosphere and the magnetosphere, a resonance mechanism known as IAR. In this work we present C/NOFS (Communications/Navigation Outage Forecasting System) Extremely Low Frequency (ELF) electric field measurements related to IAR signatures, discuss the resonance and wave propagation mechanisms in the ionosphere, and address the electromagnetic inverse problem from which electron/ion distributions can be derived. These peculiar IAR electric field measurements provide new, complementary methodologies for inferring ionospheric electron and ion density profiles, and also contribute for the investigation of ionosphere dynamics and space weather monitoring. Specifically, IAR spectral signatures measured by C/NOFS contribute for improving the International Reference Ionosphere (IRI) model, namely electron density and ion composition.

A Touch Sensing Technique Using the Effects of Extremely Low Frequency Fields on the Human Body

PubMed Central

Elfekey, Hatem; Bastawrous, Hany Ayad; Okamoto, Shogo

2016-01-01

Touch sensing is a fundamental approach in human-to-machine interfaces, and is currently under widespread use. Many current applications use active touch sensing technologies. Passive touch sensing technologies are, however, more adequate to implement low power or energy harvesting touch sensing interfaces. This paper presents a passive touch sensing technique based on the fact that the human body is affected by the surrounding extremely low frequency (ELF) electromagnetic fields, such as those of AC power lines. These external ELF fields induce electric potentials on the human body—because human tissues exhibit some conductivity at these frequencies—resulting in what is called AC hum. We therefore propose a passive touch sensing system that detects this hum noise when a human touch occurs, thus distinguishing between touch and non-touch events. The effectiveness of the proposed technique is validated by designing and implementing a flexible touch sensing keyboard. PMID:27918416

Magnetic field measurements near stand-alone transformer stations.

PubMed

Kandel, Shaiela; Hareuveny, Ronen; Yitzhak, Nir-Mordechay; Ruppin, Raphael

2013-12-01

Extremely low-frequency (ELF) magnetic field (MF) measurements around and above three stand-alone 22/0.4-kV transformer stations have been performed. The low-voltage (LV) cables between the transformer and the LV switchgear were found to be the major source of strong ELF MFs of limited spatial extent. The strong fields measured above the transformer stations support the assessment method, to be used in future epidemiological studies, of classifying apartments located right above the transformer stations as highly exposed to MFs. The results of the MF measurements above the ground around the transformer stations provide a basis for the assessment of the option of implementing precautionary procedures.

Retrospective estimation of the electric and magnetic field exposure conditions in in vitro experimental reports reveal considerable potential for uncertainty.

PubMed

Portelli, Lucas A; Falldorf, Karsten; Thuróczy, György; Cuppen, Jan

2018-04-01

Experiments on cell cultures exposed to extremely low frequency (ELF, 3-300 Hz) magnetic fields are often subject to multiple sources of uncertainty associated with specific electric and magnetic field exposure conditions. Here we systemically quantify these uncertainties based on exposure conditions described in a group of bioelectromagnetic experimental reports for a representative sampling of the existing literature. The resulting uncertainties, stemming from insufficient, ambiguous, or erroneous description, design, implementation, or validation of the experimental methods and systems, were often substantial enough to potentially make any successful reproduction of the original experimental conditions difficult or impossible. Without making any assumption about the true biological relevance of ELF electric and magnetic fields, these findings suggest another contributing factor which may add to the overall variability and irreproducibility traditionally associated with experimental results of in vitro exposures to low-level ELF magnetic fields. Bioelectromagnetics. 39:231-243, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Effects on g2/m phase cell cycle distribution and aneuploidy formation of exposure to a 60 Hz electromagnetic field in combination with ionizing radiation or hydrogen peroxide in l132 nontumorigenic human lung epithelial cells.

PubMed

Jin, Hee; Yoon, Hye Eun; Lee, Jae-Seon; Kim, Jae-Kyung; Myung, Sung Ho; Lee, Yun-Sil

2015-03-01

The aim of the present study was to assess whether exposure to the combination of an extremely low frequency magnetic field (ELF-MF; 60 Hz, 1 mT or 2 mT) with a stress factor, such as ionizing radiation (IR) or H2O2, results in genomic instability in non-tumorigenic human lung epithelial L132 cells. To this end, the percentages of G2/M-arrested cells and aneuploid cells were examined. Exposure to 0.5 Gy IR or 0.05 mM H2O2 for 9 h resulted in the highest levels of aneuploidy; however, no cells were observed in the subG1 phase, which indicated the absence of apoptotic cell death. Exposure to an ELF-MF alone (1 mT or 2 mT) did not affect the percentages of G2/M-arrested cells, aneuploid cells, or the populations of cells in the subG1 phase. Moreover, when cells were exposed to a 1 mT or 2 mT ELF-MF in combination with IR (0.5 Gy) or H2O2 (0.05 mM), the ELF-MF did not further increase the percentages of G2/M-arrested cells or aneuploid cells. These results suggest that ELF-MFs alone do not induce either G2/M arrest or aneuploidy, even when administered in combination with different stressors.

[The new magnetic therapy TAMMEF in the treatment of simple shoulder pain].

PubMed

Battisti, E; Bianciardi, L; Albanese, A; Piazza, E; Rigato, M; Galassi, G; Giordano, N

2007-01-01

Numerous studies have demonstrated the utility of extremely low frequencies (ELF) electromagnetic fields in the treatment of pain. Moreover, the effects of these fields seems to depend on their respective codes (frequency, intensity, waveform). In our study we want to assess the effects of the TAMMEF (Therapeutic Application of a Musically Modulated Electromagnetic Field) system, whose field is piloted by a musical signal and its parameters (frequency, intensity, waveform) are modified in time, randomly varying within the respective ranges, so that all possible codes can occur during a single application. Sixty subjects, affected by shoulder periarthritis were enrolled in the study and randomly divided into three groups of 20 patients each: A exposed to TAMMEF, B exposed to ELF, C exposed to a simulated field. All subjects underwent a cycle of 15 daily sessions of 30 minutes each and a clinical examination upon enrollment, after 7 days of therapy, at the end of the cycle and at a follow-up 30 days later. All the patients of groups A and B completed the therapy without the appearance of side effects: they presented a significant improvement of the subjective pain and the functional limitation, which remained stable at the follow-up examination. In group C, there was no improvement of the pain symptoms or articular functionality. This study suggests that the TAMMEF system is efficacious in the control of pain symptoms and in the reduction of functional limitation in patients with shoulder periarthritis. Moreover, the effects of the TAMMEF system cover those produced by the ELF field.

Individual estimation of exposures to extremely low frequency magnetic fields in jobs commonly held by women.

PubMed

Deadman, J E; Infante-Rivard, C

2002-02-15

Exposures to extremely low frequency (ELF) magnetic fields have not been documented extensively in occupations besides the work environments of electric or telephone utilities. A 1980-1993 study of childhood acute lymphoblastic leukemia (ALL) in Québec, Canada, gathered detailed information about the occupations of 491 mothers of ALL cases and mothers of a similar number of healthy controls. This information was combined with published data on the intensities of ELF magnetic fields associated with sources or work environments to estimate ELF magnetic field exposures for a wide range of jobs commonly held by women. Estimated exposures for 61 job categories ranged from 0.03 to 0.68 microT; the 25th, 50th, and 75th percentiles were 0.135, 0.17, and 0.23 microT, respectively. By job category, the most highly exposed jobs (>0.23 microT) included bakery worker, cashier, cook and kitchen worker, electronics worker, residential and industrial sewing machine operator, and textile machine operator. By work environment, the most highly exposed job categories were electronics worker in an assembly plant (0.70 microT) and sewing machine operators in a textile factory (0.68 microT) and shoe factory (0.66 microT). These results provide new information on expected levels of exposure in a wide range of jobs commonly held by women.

Autism-relevant social abnormalities in mice exposed perinatally to extremely low frequency electromagnetic fields.

PubMed

Alsaeed, Ibrahim; Al-Somali, Faisal; Sakhnini, Lama; Aljarallah, Omar S; Hamdan, Rayan M M; Bubishate, Saleh A; Sarfaraz, Ziyab Khan; Kamal, Amer

2014-10-01

The incidence of autism spectrum disorders (ASD) has been rising, but the causes of ASD remain largely unidentified. Collective data have implicated the increased human exposure to electromagnetic fields (EMF) in the increasing incidence of ASD. There are established biological effects of extremely low-frequency (ELF) EMF, but the relation to ASD is not investigated enough. In this study we examined the effects of perinatal exposure to ELF EMF on some ASD-relevant behavioral parameters in mice. The EMF was delivered via a Helmholtz coil pair. Male BALB/C mice were used and divided into exposed and control groups (n=8 and n=9, respectively). Tests were used to assess sociability, preference for social novelty, locomotion, anxiety, exploratory behavior, motor coordination, and olfaction. The examined mice were all males and exposed to EMF during the last week of gestation and for 7 days after delivery. The exposed mice demonstrated a lack of normal sociability and preference for social novelty while maintaining normal anxiety-like behavior, locomotion, motor coordination, and olfaction. Exposed mice also demonstrated decreased exploratory activity. We concluded that these results are supportive of the hypothesis of a causal link between exposure to ELF-EMF and ASD; however, replications of the study with further tests are recommended. Copyright © 2014 ISDN. Published by Elsevier Ltd. All rights reserved.

Effects of extremely low frequency magnetic field on production of mannatide by α-hemolytic Streptococcus.

PubMed

Zhang, Jialan; Xu, Cui; Wan, Yunlei; Gao, Mengxiang

2016-07-01

The effect of the extremely low frequency magnetic field (ELF-MF) on biomass and mannatide production by α-hemolytic Streptococcus in liquid-state fermentation culture medium was studied during shake flask culture. Magnetic field (MF) inductions, exposure times, and exposure periods varied in a range of 0-1.5 mT, 0-16 h, and six periods of incubation time, respectively. Results showed both biomass and mannatide production increased significantly at MF induction 0.4, 0.6, and 0.9 mT and decreased at both 1.2 and 1.5 mT. Biomass increased by exposure for initial and middle stages of fermentation. Mannatide production increased significantly at 4-8, 8-12, and 17-21 h. Peak yield of biomass and mannatide production increased by 10.7% and 14.0% at 25 and 27 h of incubation at 0.6 mT MF induction and exposure to 8-12 h of incubation time, compared with the control experiment, respectively. ELF-MF could also enhance the growth rate and mannatide production rate of α-hemolytic Streptococcus. However, ELF-MF did not alter α-hemolytic Streptococcus cell growth and mannatide metabolizing regulation or fermentation pattern. Mannatide production was not associated with cellular growth but rather only partially associated. Bioelectromagnetics. 37:331-337, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Calcium spiking activity and baseline calcium levels in ROS 17/2.8 cells exposed to extremely low frequency electromagnetic fields (ELF EMF).

PubMed

Shahidain, R; Mullins, R D; Sisken, J E

2001-02-01

To determine whether extremely low frequency electromagnetic fields can alter average free cytosolic calcium ion concentrations [Ca2+]i and transient increases in [Ca2+]i in populations of ROS 17/2.8 cells. Cells loaded with the calcium-selective luminescent photoprotein, aequorin, were placed in the bottom of a sample chamber, which was inserted into the gap of a previously described air gap reactor system where they were exposed either to sinusoidal magnetic fields at a variety of frequencies and flux densities or to sham conditions. Real-time recordings of photon counts due to aequorin luminescence were obtained and data were analysed with the use of probit plots. Probit plots of data obtained from cells exposed to the various magnetic fields were virtually superimposable over the data obtained for the same cultures during pre- and post-exposure sham or no-field periods. These experiments provided no evidence for any effects of ELF EMF, either positive or negative, on either average [Ca2+]i or on transient increases in [Ca2+]i.

Remote sensing of ELF/VLF radiation induced in experiments on artificial modification of the ionosphere

NASA Astrophysics Data System (ADS)

Gavrilov, B. G.; Zetser, Yu. I.; Ryakhovskii, I. A.; Poklad, Yu. V.; Ermak, V. M.

2015-07-01

In 2012, remote measurements of electromagnetic signals in the ELF/VLF band were taken at different points in Russia during experiments on artificial ionospheric modification with the powerful HF wave at the EISCAT heating facility (Tromsø, Norway). The use of the new, highly sensitive magnetometric equipment allowed signals with an amplitude of a few femtoteslas to be recorded at a distance of up to 2000 km from the source. Analysis of the measurement results discovered substantial differences in the amplitude-phase characteristics of the signals, which were caused by a change in helio-geophysical conditions in the region of heating and along the signal passage route, and features of signal propagation, which are related to their mode of guided propagation, the directivity of the source, and angles of reception.

Effects of Earth's curvature in full-wave modeling of VLF propagation

NASA Astrophysics Data System (ADS)

Qiu, L.; Lehtinen, N. G.; Inan, U. S.; Stanford VLF Group

2011-12-01

We show how to include curvature in the full-wave finite element approach to calculate ELF/VLF wave propagation in horizontally stratified earth-ionosphere waveguide. A general curvilinear stratified system is considered, and the numerical solutions of full-wave method in curvilinear system are compared with the analytic solutions in the cylindrical and spherical waveguides filled with an isotropic medium. We calculate the attenuation and height gain for modes in the Earth-ionosphere waveguide, taking into account the anisotropicity of ionospheric plasma, for different assumptions about the Earth's curvature, and quantify the corrections due to the curvature. The results are compared with the results of previous models, such as LWPC, as well as with ground and satellite observations, and show improved accuracy compared with full-wave method without including the curvature effect.

On Day-to-Day Variability of Global Lightning Activity as Quantified from Background Schumann Resonance Observations

NASA Astrophysics Data System (ADS)

Mushtak, V. C.; Williams, E. R.

2011-12-01

Among the palette of methods (satellite, VLF, ELF) for monitoring global lightning activity, observations of the background Schumann resonances (SR) provide a unique prospect for estimating the integrated activity of global lightning activity in absolute units (coul2 km2/sec). This prospect is ensured by the SR waves' low attenuation, with wavelengths commensurate with the dimensions of dominant regional lightning "chimneys", and by the accumulating methodology for background SR techniques. Another benefit is the reduction of SR measurements into a compact set of resonance characteristics (modal frequencies, intensities, and quality factors). Suggested and tested in numerical simulations by T.R. Madden in the 1960s, the idea to invert the SR characteristics for the global lightning source has been farther developed, statistically substantiated, and practically realized here on the basis of the computing power and the quantity of experimental material way beyond what the SR pioneers had at their disposal. The critical issue of the quality of the input SR parameters is addressed by implementing a statistically substantiated sanitizing procedure to dispose of the fragments of the observed time series containing unrepresentative elements - local interference of various origin and strong ELF transients originating outside the major "chimneys" represented in the source model. As a result of preliminary research, a universal empirical sanitizing criterion has been established. Due to the fact that the actual observations have been collected from a set of individually organized ELF stations with various equipment sets and calibration techniques, the relative parameters in both input (the intensities) and output (the "chimney" activities) are being used as far as possible in the inversion process to avoid instabilities caused by calibration inconsistencies. The absolute regional activities - and so the sought for global activity in absolute units - is determined in the final stage from the estimated positions and relative activities of the modeled "chimneys" using SR power spectra at the stations with the most reliable calibrations. Additional stabilization in the procedure has been achieved by exploiting the Le Come/Goltzman inversion algorithm that uses the empirically estimated statistical characteristics of the input parameters. When applied to electric and/or magnetic observations collected simultaneously in January 2009 from six ELF stations in Poland (Belsk), Japan (Moshiri), Hungary (Nagycenk), USA (Rhode Island), India (Shillong), and Antarctica (Syowa), the inversion procedure reveals a general repeatability of diurnal lightning scenarios with variations of "chimney" centroid locations by a few megameters, while the estimated regional activity has been found to vary from day to day by up to several tens of percent. A combined empirical-theoretical analysis of the collected data aimed at selecting the most reliably calibrated ELF stations is presently in progress. All the effort is being made to transform the relative lightning activity into absolute units by the time of this meeting. The authors are greatly thankful to all the experimentalists who generously provided their observations and related information for this study.

Interpretation of Epithelial Lining Fluid Concentrations of Antibiotics against Methicillin Resistant Staphylococcus aureus.

PubMed

Kiem, Sungmin; Schentag, Jerome J

2014-12-01

Although antibiotics whose epithelial lining fluid (ELF) concentrations are reported high tend to be preferred in treatment of pneumonia, measurement of ELF concentrations of antibiotics could be misled by contamination from lysis of ELF cells and technical errors of bronchoalveolar lavage (BAL). In this review, ELF concentrations of anti-methicillin resistant Staphylococcus aureus (MRSA) antibiotics were interpreted considering above confounding factors. An equation used to explain antibiotic diffusion into CSF (cerebrospinal fluid) was adopted: ELF/free serum concentration ratio = 0.96 + 0.091 × ln (partition coefficient / molecular weight(1/2)). Seven anti-MRSA antibiotics with reported ELF concentrations were fitted to this equation to see if their ELF concentrations were explainable by the penetration capacity only. Then, outliers were modeled under the assumption of varying contamination from lysed ELF cells (test range 0-10% of ELF volume). ELF concentrations of oritavancin, telavancin, tigecycline, and vancomycin were well described by the diffusion equation, with or without additional impact from cell lysis. For modestly high ELF/free serum concentration ratio of linezolid, technical errors of BAL should be excluded. Although teicoplanin and iclaprim showed high ELF/free serum ratios also, their protein binding levels need to be cleared for proper interpretation. At the moment, it appears very premature to use ELF concentrations of anti-MRSA antibiotics as a relevant guide for treatment of lung infections by MRSA.

Interpretation of Epithelial Lining Fluid Concentrations of Antibiotics against Methicillin Resistant Staphylococcus aureus

PubMed Central

Schentag, Jerome J

2014-01-01

Although antibiotics whose epithelial lining fluid (ELF) concentrations are reported high tend to be preferred in treatment of pneumonia, measurement of ELF concentrations of antibiotics could be misled by contamination from lysis of ELF cells and technical errors of bronchoalveolar lavage (BAL). In this review, ELF concentrations of anti-methicillin resistant Staphylococcus aureus (MRSA) antibiotics were interpreted considering above confounding factors. An equation used to explain antibiotic diffusion into CSF (cerebrospinal fluid) was adopted: ELF/free serum concentration ratio = 0.96 + 0.091 × ln (partition coefficient / molecular weight1/2). Seven anti-MRSA antibiotics with reported ELF concentrations were fitted to this equation to see if their ELF concentrations were explainable by the penetration capacity only. Then, outliers were modeled under the assumption of varying contamination from lysed ELF cells (test range 0-10% of ELF volume). ELF concentrations of oritavancin, telavancin, tigecycline, and vancomycin were well described by the diffusion equation, with or without additional impact from cell lysis. For modestly high ELF/free serum concentration ratio of linezolid, technical errors of BAL should be excluded. Although teicoplanin and iclaprim showed high ELF/free serum ratios also, their protein binding levels need to be cleared for proper interpretation. At the moment, it appears very premature to use ELF concentrations of anti-MRSA antibiotics as a relevant guide for treatment of lung infections by MRSA. PMID:25566401

Non-Seismic Pre-Earthquake Phenomena and their Effects on the Biosphere

NASA Astrophysics Data System (ADS)

Freund, Friedemann; Stolc, Viktor

2013-04-01

Earthquakes occur when tectonic stresses build up deep in the Earth and reach the threshold of catastrophic rupture. During the build-up of stress, long before rupture, processes occur in the Earth crust that lead to the activation of highly mobile electronic charge carriers. One remarkable property of these charge carriers is that they are able to flow out of the stressed rock volume into surrounding rocks. Such an outflow constitutes an electric current, which generates electromagnetic (EM) signals. If the outflow occurs in bursts, the EM signals will consist of short EM pulses. If the outflow is continuous, the currents are likely to fluctuate, generating EM emissions over a wide frequency range. Only the ultralow and extremely low frequency (ULF/ELF) waves can travel through kilometers of rock and reach the Earth surface. These ULF/ELF emissions can last for hours or days. In a companion poster we report on their effects on crucial biochemical reactions in living organisms. Another remarkable property of the outflowing charge carriers is that they are (i) positively charged and (ii) highly oxidizing. When they reach the Earth surface from below, they build up microscopic but very steep electric fields, strong enough to field-ionize air molecules, i.e. rip an electron off air molecules. As a result the air above the epicenter of an impending major earthquake often becomes heavily laden with positive airborne ions. Medical research has long shown that positive airborne ions cause changes in the stress hormone level in animals and humans. Therefore, positive airborne ions are a likely cause for unusual reactions among animals and humans. When the outflowing charge carriers cross from rocks into water, they oxidize the water to hydrogen peroxide. This process, plus oxidation reactions involving dissolved organic compounds in the ground water, are likely candidates for causing behavioral changes, even death, among aquatic animals.

Pharmacodynamics of levofloxacin in a murine pneumonia model of Pseudomonas aeruginosa infection: determination of epithelial lining fluid targets.

PubMed

Louie, Arnold; Fregeau, Christine; Liu, Weiguo; Kulawy, Robert; Drusano, G L

2009-08-01

The dose choice for Pseudomonas aeruginosa remains a matter of debate. The actual exposure targets required for multilog killing of organisms at the primary infection site have not been delineated. We studied Pseudomonas aeruginosa PAO1 using a murine model of pneumonia. We employed a large mathematical model to fit all the concentration-time data in plasma and epithelial lining fluid (ELF) as well as colony counts in lung simultaneously for all drug doses. Penetration into ELF was calculated to be approximately 77.7%, as indexed to the ratio of the area under the concentration-time curve for ELF (AUC(ELF)) to the AUC(plasma). We determined the ELF concentration-time profile required to drive a stasis response as well as 1-, 2-, or 3-log(10)(CFU/g) kill. AUC/MIC ratios of 12.4, 31.2, 62.8, and 127.6 were required to drive these bacterial responses. Emergence of resistance was seen only at the two lowest doses (three of five animals at 50 mg/kg [body weight] and one of five animals at 100 mg/kg). The low exposure targets were likely driven by a low mutational frequency to resistance. Bridging to humans was performed using Monte Carlo simulation. With a 750-mg levofloxacin dose, target attainment rates fell below 90% at 4 mg/liter, 1 mg/liter, and 0.5 mg/liter for 1-, 2-, and 3-log kills, respectively. Given the low exposure targets seen with this strain, we conclude that levofloxacin at a 750-mg dose is not adequate for serious Pseudomonas aeruginosa pneumonia as a single agent. More isolates need to be studied to make these observations more robust.

Residential proximity to electromagnetic field sources and birth weight: Minimizing residual confounding using multiple imputation and propensity score matching.

PubMed

de Vocht, Frank; Lee, Brian

2014-08-01

Studies have suggested that residential exposure to extremely low frequency (50 Hz) electromagnetic fields (ELF-EMF) from high voltage cables, overhead power lines, electricity substations or towers are associated with reduced birth weight and may be associated with adverse birth outcomes or even miscarriages. We previously conducted a study of 140,356 singleton live births between 2004 and 2008 in Northwest England, which suggested that close residential proximity (≤ 50 m) to ELF-EMF sources was associated with reduced average birth weight of 212 g (95%CI: -395 to -29 g) but not with statistically significant increased risks for other adverse perinatal outcomes. However, the cohort was limited by missing data for most potentially confounding variables including maternal smoking during pregnancy, which was only available for a small subgroup, while also residual confounding could not be excluded. This study, using the same cohort, was conducted to minimize the effects of these problems using multiple imputation to address missing data and propensity score matching to minimize residual confounding. Missing data were imputed using multiple imputation using chained equations to generate five datasets. For each dataset 115 exposed women (residing ≤ 50 m from a residential ELF-EMF source) were propensity score matched to 1150 unexposed women. After doubly robust confounder adjustment, close proximity to a residential ELF-EMF source remained associated with a reduction in birth weight of -116 g (95% confidence interval: -224:-7 g). No effect was found for proximity ≤ 100 m compared to women living further away. These results indicate that although the effect size was about half of the effect previously reported, close maternal residential proximity to sources of ELF-EMF remained associated with suboptimal fetal growth. Copyright © 2014 Elsevier Ltd. All rights reserved.

Arc and resistance welding and tumours of the endocrine glands: a Swedish case-control study with focus on extremely low frequency magnetic fields.

PubMed

Håkansson, N; Stenlund, C; Gustavsson, P; Johansen, C; Floderus, B

2005-05-01

Mechanisms for potential effects of extremely low frequency (ELF) magnetic fields on carcinogenesis have not been identified. A potential pathway could be an interaction with the endocrine system. To analyse occupational exposure to ELF magnetic fields from welding, and tumours of the endocrine glands. This case-control study was based on a cohort with an increased prevalence of high exposed individuals. A total of 174 incident cases of tumours of the endocrine glands, 1985-94, were identified and data were obtained from 140 (80%) of these cases; 1692 controls frequency matched on sex and age were selected, and information on 1306 (77%) individuals was obtained. A short questionnaire was sent to a work administrator at the workplaces of the cases and controls. The exposure assessment was based on questions about job tasks, exposure to different types of welding, and exposure to solvents. There was an overall increased risk for all tumours of the endocrine glands for individuals who had been welding sometime during the follow up. The increased risk was attributable to arc welding; for resistance welding there was no clear evidence of an association. We found an increased risk for the adrenal glands in relation to arc welding, and for the parathyroid glands in relation to both arc welding and resistance welding. An imprecise increase in risk was also noted for tumours of the pituitary gland for arc welding. No confounding effect was found for solvent exposure, and there was no sign of biological interaction. The increased risks of endocrine gland tumours related to welding might be explained by exposure to high levels of ELF magnetic fields.

Arc and resistance welding and tumours of the endocrine glands: a Swedish case-control study with focus on extremely low frequency magnetic fields

PubMed Central

Hakansson, N; Stenlund, C; Gustavsson, P; Johansen, C; Floderus, B

2005-01-01

Background: Mechanisms for potential effects of extremely low frequency (ELF) magnetic fields on carcinogenesis have not been identified. A potential pathway could be an interaction with the endocrine system. Aims: To analyse occupational exposure to ELF magnetic fields from welding, and tumours of the endocrine glands. Methods: This case-control study was based on a cohort with an increased prevalence of high exposed individuals. A total of 174 incident cases of tumours of the endocrine glands, 1985–94, were identified and data were obtained from 140 (80%) of these cases; 1692 controls frequency matched on sex and age were selected, and information on 1306 (77%) individuals was obtained. A short questionnaire was sent to a work administrator at the workplaces of the cases and controls. The exposure assessment was based on questions about job tasks, exposure to different types of welding, and exposure to solvents. Results: There was an overall increased risk for all tumours of the endocrine glands for individuals who had been welding sometime during the follow up. The increased risk was attributable to arc welding; for resistance welding there was no clear evidence of an association. We found an increased risk for the adrenal glands in relation to arc welding, and for the parathyroid glands in relation to both arc welding and resistance welding. An imprecise increase in risk was also noted for tumours of the pituitary gland for arc welding. No confounding effect was found for solvent exposure, and there was no sign of biological interaction. Conclusion: The increased risks of endocrine gland tumours related to welding might be explained by exposure to high levels of ELF magnetic fields. PMID:15837851

Lightning Sensors for Observing, Tracking and Nowcasting Severe Weather

PubMed Central

Price, Colin

2008-01-01

Severe and extreme weather is a major natural hazard all over the world, often resulting in major natural disasters such as hail storms, tornados, wind storms, flash floods, forest fires and lightning damages. While precipitation, wind, hail, tornados, turbulence, etc. can only be observed at close distances, lightning activity in these damaging storms can be monitored at all spatial scales, from local (using very high frequency [VHF] sensors), to regional (using very low frequency [VLF] sensors), and even global scales (using extremely low frequency [ELF] sensors). Using sensors that detect the radio waves emitted by each lightning discharge, it is now possible to observe and track continuously distant thunderstorms using ground networks of sensors. In addition to the number of lightning discharges, these sensors can also provide information on lightning characteristics such as the ratio between intra-cloud and cloud-to-ground lightning, the polarity of the lightning discharge, peak currents, charge removal, etc. It has been shown that changes in some of these lightning characteristics during thunderstorms are often related to changes in the severity of the storms. In this paper different lightning observing systems are described, and a few examples are provided showing how lightning may be used to monitor storm hazards around the globe, while also providing the possibility of supplying short term forecasts, called nowcasting. PMID:27879700

Comparative Analysis of Methods of Evaluating the Lower Ionosphere Parameters by Tweek Atmospherics

NASA Astrophysics Data System (ADS)

Krivonos, A. P.; Shvets, A. V.

2016-12-01

Purpose: A comparative analysis of the phase and frequency methods for determining the Earth-ionosphere effective waveguide heights for the basic and higher types of normal waves (modes) and distance to the source of radiation - lightning - has been made by analyzing pulse signals in the ELF-VLF range - tweek-atmospherics (tweeks). Design/methodology/approach: To test the methods in computer simulations, the tweeks waveforms were synthesized for the Earth-ionosphere waveguide model with the exponential conductivity profile of the lower ionosphere. The calculations were made for a 20-40 dB signal/noise ratio. Findings: The error of the frequency method of determining the effective height of the waveguide for different waveguide modes was less than 0.5 %. The error of the phase method for determining the effective height of the waveguide was less than 0.8 %. Errors in determining the distance to the lightning was less than 1 % for the phase method, and less than 5 % for the frequency method for the source ranges 1000-3000 km. Conclusions: The analysis results have showed the accuracy of the frequency and phase methods being practically the same within distances of 1000-3000 km. For distances less than 1000 km, the phase method shows a more accurate evaluation of the range, so the combination of the two methods can be used to improve estimating the tweek’s propagation path parameters.

Theoretical investigation of the generation and injection of electromagnetic waves in space plasma by means of a long-orbiting tether

NASA Technical Reports Server (NTRS)

Dobrowolny, M.

1981-01-01

Analysis of the various mechanisms of electromagnetic wave generation by the shuttle-borne orbiting tether of the T.S.S. Facility shows that significant electrodynamic power levels are available even when overestimating the loss mechanisms expected to intervene. This electrodynamic power is in part dissipated by Joule losses in the tether, in part goes to accelerate electrons through the sheath surrounding the balloon (when in a downward deployment), and in part goes into e.m. wave generation. A preliminary estimate shows that a 100 km tether in orbit would produce ULF/ELF signals that are detectable on the ground with state-of-the-art magnetometric instrumentation.

Effect of extremely low frequency electromagnetic field on brain histopathology of Caspian Sea Cyprinus carpio.

PubMed

Samiee, Farzaneh; Samiee, Keivandokht

2017-01-01

There is limited research on the effect of electromagnetic field on aquatic organisms, especially freshwater fish species. This study was conducted to evaluate the effect of extremely low frequency electromagnetic field (ELF-EMF) (50 Hz) exposure on brain histopathology of Cyprinus carpio, one of the important species of Caspian Sea with significant economic value. A total of 200 healthy fish were used in this study. They were classified randomly in two groups: sham-exposed group and experimental group, which were exposed to five different magnetic field intensities (0.1, 1, 3, 5, and 7 mT) at two different exposure times (0.5 and 1 h). Histologic results indicate that exposure of C. carpio to artificial ELF-EMF caused severe histopathological changes in the brain at field intensities ≥3 mT leading to brain necrosis. Field intensity and duration of exposure were key parameters in induction of lesion in the brain. Further studies are needed to elucidate exact mechanism of EMF exposure on the brain.

X-ray-induced apoptosis of BEL-7402 cell line enhanced by extremely low frequency electromagnetic field in vitro.

PubMed

Jian, Wen; Wei, Zhao; Zhiqiang, Cheng; Zheng, Fang

2009-02-01

This study was designed to test whether extremely low frequency electromagnetic field (ELF-EMF) could enhance the apoptosis-induction effect of X-ray radiotherapy on liver cancer cell line BEL-7402 in vitro. EMF exposure was performed inside an energized solenoid coil. X-ray irradiation was performed using a linear accelerator. Apoptosis rates of BEL-7402 cells were analyzed using Annexin V-Fit Apoptosis Detection kit. Apoptosis rates of EMF group and sham EMF group were compared when combined with X-ray irradiation. Our results suggested that the apoptosis rate of BEL-7402 cells exposed to low doses of X-ray irradiation could be significantly increased by EMF. More EMF exposures obtain significantly higher apoptosis rates than fewer EMF exposures when combined with 2 Gy X-ray irradiation. These findings suggested that ELF-EMF could augment the cell apoptosis effects of low doses of X-ray irradiation on BEL-7402 cells in a synergistic and cumulative way. Copyright 2008 Wiley-Liss, Inc.

Effects of extremely low frequency electromagnetic field on the health of workers in automotive industry.

PubMed

Liu, Xin; Zhao, Longyu; Yu, Duo; Ma, Shumei; Liu, Xiaodong

2013-12-01

To observe the effects of extremely low frequency electromagnetic fields (ELF-EMFs) in automotive industry on occupational workers. A total of 704 workers were investigated, and 374 workers were chosen and divided into two groups (control group and exposure group) according to the inclusive criteria, namely male with age 20-40 years old and ≥ 2 years of exposure. The intensities of ELF-EMFs and noise were detected with EFA-300 Field Analyzer (Narda company, Pfullingen, Germany) and AWA5610D integrating sound level meter (Hangzhou Aihua Instruments Co., Ltd, Hangzhou, China), respectively. Survey data were collected by questionnaire, and the physical check-up was done in hospital. All the data were input into SPSS17.0 software (SPSS Inc, Chicago, USA), and the appropriate statistic analyses were carried out. The intensity of EMFs in exposure group was significantly higher than that in control group (p < 0.05), while the noise in two workplaces showed no difference (p>0.05). The survey data collected by questionnaires showed that the symptoms of loss of hair in exposure group were significantly different as compared with that in control group (p < 0.05). The check-up parameters of cardiovascular, liver and hematology system showed significant differences between the two groups (p < 0.05). Survey and check-up data suggest that exposure to ELF-EMFs might have effects on the nervous, cardiovascular, liver, and hematology system of workers.

Continuous exposure to low amplitude extremely low frequency electrical fields characterizing the vascular streaming potential alters elastin accumulation in vascular smooth muscle cells.

PubMed

Bergethon, Peter R; Kindler, Dean D; Hallock, Kevin; Blease, Susan; Toselli, Paul

2013-07-01

In normal development and pathology, the vascular system depends on complex interactions between cellular elements, biochemical molecules, and physical forces. The electrokinetic vascular streaming potential (EVSP) is an endogenous extremely low frequency (ELF) electrical field resulting from blood flowing past the vessel wall. While generally unrecognized, it is a ubiquitous electrical biophysical force to which the vascular tree is exposed. Extracellular matrix elastin plays a central role in normal blood vessel function and in the development of atherosclerosis. It was hypothesized that ELF fields of low amplitude would alter elastin accumulation, supporting a link between the EVSP and the biology of vascular smooth muscle cells. Neonatal rat aortic smooth muscle cell cultures were exposed chronically to electrical fields characteristic of the EVSP. Extracellular protein accumulation, DNA content, and electron microscopic (EM) evaluation were performed after 2 weeks of exposure. Stimulated cultures showed no significant change in cellular proliferation as measured by the DNA concentration. The per-DNA normalized protein in the extracellular matrix was unchanged while extracellular elastin accumulation decreased 38% on average. EM analysis showed that the stimulated cells had a 2.85-fold increase in mitochondrial number. These results support the formulation that ELF fields are a potential factor in both normal vessel biology and in the pathogenesis of atherosclerotic diseases including heart disease, stroke, and peripheral vascular disease. Copyright © 2013 Wiley Periodicals, Inc.

An investigation into the vector ellipticity of extremely low frequency magnetic fields from appliances in UK homes

NASA Astrophysics Data System (ADS)

Ainsbury, Elizabeth A.; Conein, Emma; Henshaw, Denis L.

2005-07-01

Elliptically polarized magnetic fields induce higher currents in the body compared with their plane polarized counterparts. This investigation examines the degree of vector ellipticity of extremely low frequency magnetic fields (ELF-MFs) in the home, with regard to the adverse health effects reportedly associated with ELF-MFs, for instance childhood leukaemia. Tri-axial measurements of the magnitude and phase of the 0-3000 Hz magnetic fields, produced by 226 domestic mains-fed appliances of 32 different types, were carried out in 16 homes in Worcestershire in the summer of 2004. Magnetic field strengths were low, with average (RMS) values of 0.03 ± 0.02 µT across all residences. In contrast, background field ellipticities were high, on average 47 ± 11%. Microwave and electric ovens produced the highest ellipticities: mean respective values of 21 ± 21% and 21 ± 17% were observed 20 cm away from these appliances. There was a negative correlation between field strength and field polarization, which we attribute to the higher relative field contribution close to each individual (single-phase) appliance. The measurements demonstrate that domestic magnetic fields are extremely complex and cannot simply be characterized by traditional measurements such as time-weighted average or peak exposure levels. We conclude that ellipticity should become a relevant metric for future epidemiological studies of health and ELF-MF exposure. This work is supported by the charity CHILDREN with LEUKAEMIA, registered charity number 298405.

ELF signals from the Central Italy Electromagnetic Network (CIEN) at the time of the 2012 Emilia-Romagna earthquakes

NASA Astrophysics Data System (ADS)

Fidani, Cristiano

2013-04-01

A network devoted to a continuous monitoring of LF, VLF transmitters and ELF signals was set up in Central Italy, and has been operating since 2006, which is currently composed of 9 stations in 9 different Italian cities. From the beginning of 2012, improvements have been carried out on the stability of CIEN by updating all the stations with UPS and web connections. Moreover, a reduction in the amount of data stored was performed so to permit a real time monitoring of the network by web. Specifically, a 100kb/day was fixed to record the VLF power spectra intervals around the transmitter frequencies every 5 minutes. Similarly, a 600kb/day was fixed to record the ELF power spectra intervals, which was logarithmic spaced in frequency every 5 seconds. Furthermore, different physical measurements at each CIEN site have been recently initiated to better understand the sources of some signals. In order to do so, the Fermo and Torre Pellice stations have been equipped with Geiger counters to monitor atmospheric radioactivity, underground thermometers, as well as meteorological stations to record atmospheric temperature, humidity, wind speed and direction, along with atmospheric pressure and rainfall. The Torre Pellice Station had already been equipped with a magnetometer, a Radon-meter and a compass to check the direction of the geomagnetic field. The Chieti station had already been equipped with a magnetometer and an underground current detector. The Perugia and Rieti stations had already been equipped with seismometers and a network to capture transient luminous phenomena in the atmosphere. On May 20th and 29th 2012, two strong earthquakes struck the Emilia-Romagna Region with a magnitude M=5.9 and M=5.8, respectively. The earthquakes caused 27 fatal causalities and significant ground failures. The observations relative to this seismic period were investigated relative to their ELF band electric fields. Observations were thoroughly analysed from the Zocca station, the closest (50km) CIEN monitoring station to the Emilia-Romagna epicenter. Date from other stations were examined to reveal any possible differences. Many horizontal electric oscillations from April 1 - June 30, 2012, were seen. Most of these appeared at the time of rainfalls, which were revealed by the Zocca station on the same days. Electric oscillations under 100 Hz appeared from May 10 - 11, 2012, when there was no recorded meteorological activity. On May 26, 2012, strong ELF oscillations occurred at the Zocca station. This station had not detected ELF horizontal oscillations for many years prior to Emilia-Romagna seismic events in May 2012. Whereas, signals were revealed in mid-April 2012 and increased in number and intensity around the dates of the quakes.

Protective effects of pulmonary epithelial lining fluid on oxidative stress and DNA single-strand breaks caused by ultrafine carbon black, ferrous sulphate and organic extract of diesel exhaust particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chuang, Hsiao-Chi; Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan; Cheng, Yi-Ling

Pulmonary epithelial lining fluid (ELF) is the first substance to make contact with inhaled particulate matter (PM) and interacts chemically with PM components. The objective of this study was to determine the role of ELF in oxidative stress, DNA damage and the production of proinflammatory cytokines following physicochemical exposure to PM. Ultrafine carbon black (ufCB, 15 nm; a model carbonaceous core), ferrous sulphate (FeSO{sub 4}; a model transition metal) and a diesel exhaust particle (DEP) extract (a model organic compound) were used to examine the acellular oxidative potential of synthetic ELF and non-ELF systems. We compared the effects of exposuremore » to ufCB, FeSO{sub 4} and DEP extract on human alveolar epithelial Type II (A549) cells to determine the levels of oxidative stress, DNA single-strand breaks and interleukin-8 (IL-8) production in ELF and non-ELF systems. The effects of ufCB and FeSO{sub 4} on the acellular oxidative potential, cellular oxidative stress and DNA single-strand breakage were mitigated significantly by the addition of ELF, whereas there was no decrease following treatment with the DEP extract. There was no significant effect on IL-8 production following exposure to samples that were suspended in ELF/non-ELF systems. The results of the present study indicate that ELF plays an important role in the initial defence against PM in the pulmonary environment. Experimental components, such as ufCB and FeSO{sub 4}, induced the production of oxidative stress and led to DNA single-strand breaks, which were moderately prevented by the addition of ELF. These findings suggest that ELF plays a protective role against PM-driven oxidative stress and DNA damage. -- Highlights: ► To determine the role of ELF in ROS, DNA damage and IL-8 after exposure to PM. ► ufCB, FeSO{sub 4} and DEP extract were used to examine the protective effects of ELF. ► PM-driven oxidative stress and DNA single-strand breakage were mitigated by ELF. ► The findings suggest that ELF has a protective role against PM. ► The synthetic ELF system could reduce the use of animals in PM-driven ROS testing.« less

The effect of a gamma ray flare on Schumann resonances

NASA Astrophysics Data System (ADS)

Nickolaenko, A. P.; Kudintseva, I. G.; Pechony, O.; Hayakawa, M.; Hobara, Y.; Tanaka, Y. T.

2012-09-01

We describe the ionospheric modification by the SGR 1806-20 gamma flare (27 December 2004) seen in the global electromagnetic (Schumann) resonance. The gamma rays lowered the ionosphere over the dayside of the globe and modified the Schumann resonance spectra. We present the extremely low frequency (ELF) data monitored at the Moshiri observatory, Japan (44.365° N, 142.24° E). Records are compared with the expected modifications, which facilitate detection of the simultaneous abrupt change in the dynamic resonance pattern of the experimental record. The gamma flare modified the current of the global electric circuit and thus caused the "parametric" ELF transient. Model results are compared with observations enabling evaluation of changes in the global electric circuit.

Reaction of the high-latitude lower ionosphere to solar proton events from observations in the ELF range

NASA Astrophysics Data System (ADS)

Lebed', O. M.; Larchenko, A. V.; Pil'gaev, S. V.; Fedorenko, Yu. V.

2017-01-01

The reaction of the lower ionosphere to the solar proton events that occurred in 2011-2012 is studied in this paper based on the results of measurements of the propagation velocity and the E z / H τ ratio of the low-frequency electromagnetic pulses (atmospherics) in the ELF range at the high-latitude observatories Lovozero and Barentsburg. With numerical modeling methods, it is shown that horizontal local irregularities of the lower ionosphere conductivity profile could be a cause of the splashes in the E z / H τ ratio observed in the experiment during the solar proton event of March 7, 2012, which was a unique event in both the proton flux value and energy.

BIOLOGICAL EFFECTS AND DOSIMETRY OF STATIC AND ELF (EXTREMELY LOW FREQUENCY) ELECTROMAGNETIC FIELDS

EPA Science Inventory

The book offers a good introduction to the research field for students, as well as a valuable overall review for the experienced investigator. The six chapters on interactions provide concise descriptions of physical processes for natural and man-made environmental exposures and ...

Global thunderstorm activity estimation based on number of transients in ELF-band

NASA Astrophysics Data System (ADS)

Ondraskova, Adriena; Sevcik, Sebastian

2017-04-01

Schumann resonances (SR) are resonant electromagnetic oscillations in extremely low frequency band (ELF, 3 Hz - 3 kHz), which arise in the Earth-ionosphere cavity due to lightning activity in planetary range. The time records in the ELF-band consist of background signals and ELF transients/Q-bursts superimposed on the background exceeding it by a factor of 5 - 10. The former are produced by the common worldwide thunderstorm activity (100 - 150 events per second), the latter origin from individual intense distant lightning discharges (100 - 120 powerful strokes per hour). A Q-burst is produced by a combination of direct and antipodal pulses and the decisive factor for its shape follows from the source-to-observer distance. Diurnal/seasonal variations of global thunderstorm activity can be deduced from spectral amplitudes of SR modes. Here we focus on diurnal/seasonal variations of the number of ELF-transients assuming that it is another way of lightning activity estimation. To search for transients, our own code was applied to the SR vertical electric component measured in October 2004 - October 2008 at the Astronomical and Geophysical Observatory of FMPI CU, Slovakia. Criteria for the identification of the burst are chosen on the basis of the transient amplitudes and their morphological features. Monthly mean daily variations in number of transients showed that African focus dominates at 14 - 16 h UT and it is more active in comparison with Asian source, which dominates at 5 - 8 h UT in dependence on winter or summer month. American source had surprisingly slight response. Meteorological observations in South America aiming to determine lightning hotspots on the Earth indicate that flash rate in this region is greatest during nocturnal 0 h - 3 h local standard time. This fact may be interpreted that Asian and South American sources contribute together in the same UT. Cumulative spectral amplitude of the first three SR modes compared with number of ELF-transients in monthly averaged diurnal variations quite successfully confirmed, that the number of transients could be a suitable criterion for the quantification of global lightning activity.

No effects of power line frequency extremely low frequency electromagnetic field exposure on selected neurobehavior tests of workers inspecting transformers and distribution line stations versus controls.

PubMed

Li, Li; Xiong, De-fu; Liu, Jia-wen; Li, Zi-xin; Zeng, Guang-cheng; Li, Hua-liang

2014-03-01

We aimed to evaluate the interference of 50 Hz extremely low frequency electromagnetic field (ELF-EMF) occupational exposure on the neurobehavior tests of workers performing tour-inspection close to transformers and distribution power lines. Occupational short-term "spot" measurements were carried out. 310 inspection workers and 300 logistics staff were selected as exposure and control. The neurobehavior tests were performed through computer-based neurobehavior evaluation system, including mental arithmetic, curve coincide, simple visual reaction time, visual retention, auditory digit span and pursuit aiming. In 500 kV areas electric field intensity at 71.98% of total measured 590 spots were above 5 kV/m (national occupational standard), while in 220 kV areas electric field intensity at 15.69% of total 701 spots were above 5 kV/m. Magnetic field flux density at all the spots was below 1,000 μT (ICNIRP occupational standard). The neurobehavior score changes showed no statistical significance. Results of neurobehavior tests among different age, seniority groups showed no significant changes. Neurobehavior changes caused by daily repeated ELF-EMF exposure were not observed in the current study.

Effect of 60-Hz magnetic fields on ultraviolet light-induced mutation and mitotic recombination in Saccharomyces cerevisiae.

PubMed

Ager, D D; Radul, J A

1992-12-01

The purpose of this study was to examine the effect of extremely low frequency (ELF) magnetic fields on the induction of genetic damage. In general, mutational studies involving ELF magnetic fields have proven negative. However, studies examining sister-chromatid exchange and chromosome aberrations have yielded conflicting results. In this study, we have examined whether 60-Hz magnetic fields are capable of inducing mutation or mitotic recombination in the yeast Saccharomyces cerevisiae. In addition we determined whether magnetic fields were capable of altering the genetic response of S. cerevisiae to UV (254 nm). We measured the frequencies of induced mutation, gene conversion and reciprocal mitotic crossing-over for exposures to magnetic fields alone (1 mT) or in combination with various UV exposures (2-50 J/m2). These experiments were performed using a repair-proficient strain (RAD+), as well as a strain of yeast (rad3) which is incapable of excising UV-induced thymine dimers. Magnetic field exposures did not induce mutation, gene conversion or reciprocal mitotic crossing-over in either of these strains, nor did the fields influence the frequencies of UV-induced genetic events.

Effects of force load, muscle fatigue and extremely low frequency magnetic stimulation on EEG signals during side arm lateral raise task.

PubMed

Wang, Ying; Cao, Liu; Hao, Dongmei; Rong, Yao; Yang, Lin; Zhang, Song; Chen, Fei; Zheng, Dingchang

2017-05-01

This study was to quantitatively investigate the effects of force load, muscle fatigue and extremely low frequency (ELF) magnetic stimulation on electroencephalography (EEG) signal features during side arm lateral raise task. EEG signals were recorded by a BIOSEMI Active Two system with Pin-Type active-electrodes from 18 healthy subjects when they performed the right arm side lateral raise task (90° away from the body) with three different loads (0 kg, 1 kg and 3 kg; their order was randomized among the subjects) on the forearm. The arm maintained the loads until the subject felt exhausted. The first 10 s recording for each load was regarded as non-fatigue status and the last 10 s before the subject was exhausted as fatigue status. The subject was then given a 5 min resting between different loads. Two days later, the same experiment was performed on each subject except that ELF magnetic stimulation was applied to the subject's deltoid muscle during the 5 min resting period. EEG features from C3 and C4 electrodes including the power of alpha, beta and gamma and sample entropy were analyzed and compared between different loads, non-fatigue/fatigue status, and with/without ELF magnetic stimulation. The key results were associated with the change of the power of alpha band. From both C3-EEG and C4-EEG, with 1 kg and 3 kg force loads, the power of alpha band was significantly smaller than that from 0 kg for both non-fatigue and fatigue periods (all p  <  0.05). However, no significant difference of the power in alpha between 1 kg and 3 kg was observed (p  >  0.05 for all the force loads except C4-EEG with ELF simulation). The power of alpha band at fatigue status was significantly increased for both C3-EEG and C4-EEG when compared with the non-fatigue status (p  <  0.01 for all the force loads except 3 kg force from C4-EEG). With magnetic stimulation, the powers of alpha from C3-EEG and C4-EEG were significantly decreased than without stimulation (all p  <  0.05), and the difference in the power of alpha between fatigue and non-fatigue status disappeared with 1 kg and 3 kg force loads, The powers of beta and gamma bands and SampEn were not significantly different between different force loads, between fatigue and non-fatigue status, and between with and without ELF magnetic stimulation (all p  >  0.05, except between non-fatigue and fatigue with magnetic stimulation in gamma band of C3-EEG at 1 kg, and in the SampEn at 1 kg and 3 kg force loads from C4-EEG). Our study comprehensively quantified the effects of force, fatigue and the ELF magnetic stimulation on EEG features with difference forces, fatigue status and ELF magnetic stimulation.

Extremely Low Frequency (ELF) Communications System Ecological Monitoring Program Summary of 1990 Progress

DTIC Science & Technology

1991-12-01

evenness, and richness were used to characterize colonization patterns. Processing rates were determined for both fresh and autumn- abscised leaves... acid precipitation on nutrient levels in a forest soil 3 and foliage of red pine seedlings. Houghton, MI: School of Forestry and Wood Products

The Continuing Medical Surveillance of Personnel Exposed to Extremely Low Frequency (ELF) Electromagnetic Fields.

DTIC Science & Technology

1976-03-25

ly be related to diet and personal ha bits , tienetic predis position, or concurrent medical disease. More extensive use of laboratory techniques...17-OH Same as above steroids, 17 ketogenic steroids, creatinine clearance Stool Ova and parasites, culture for Same as above euteric pathogenis Semen

The Science ELF: Assessing the Enquiry Levels Framework as a Heuristic for Professional Development

ERIC Educational Resources Information Center

Wheeler, Lindsay B.; Bell, Randy L.; Whitworth, Brooke A.; Maeng, Jennifer L.

2015-01-01

This study utilized an explanatory sequential mixed methods approach to explore randomly assigned treatment and control participants' frequency of inquiry instruction in secondary science classrooms. Eleven treatment participants received professional development (PD) that emphasized a structured approach to inquiry instruction, while 10 control…

Source Mechanisms and Radio Effects of Ionospheric Plasma

DTIC Science & Technology

1992-11-01

naturally-occurring ELF hiss simi- lar to that observed on other low-altitude satellites (Gurnett and Burns, 1968; Mosier, 1971; Muzzio and Angerami ...satellite, J. Geophys. Res., 76, 1713, 1971. Muzzio, J.L.R., and J.J. Angerami , OGO 4 observations of ex- tremely low-frequency hiss, J. Geophys. Res

Compilation of 1985 annual reports of the Navy elf (extremely low frequency) communications system ecological monitoring program. Volume 2. Tabs D-G. Annual progress report, January-December 1985

DOE Office of Scientific and Technical Information (OSTI.GOV)

Band, R.N.; Snider, R.J.; Snider, R.M.

1986-07-01

This volume consists of the following reports: Soil Amoeba; Soil and Litter Arthropoda and Earthworm Studies; Biological Studies on Pollinating Insects: Megachilid Bees; Small Vertebrates: Small Mammals and Nesting Birds.

Mutations in the Nucleolar Phosphoprotein, Nucleophosmin, Promote the Expression of the Oncogenic Transcription Factor MEF/ELF4 in Leukemia Cells and Potentiates Transformation*

PubMed Central

Ando, Koji; Tsushima, Hideki; Matsuo, Emi; Horio, Kensuke; Tominaga-Sato, Shinya; Imanishi, Daisuke; Imaizumi, Yoshitaka; Iwanaga, Masako; Itonaga, Hidehiro; Yoshida, Shinichiro; Hata, Tomoko; Moriuchi, Ryozo; Kiyoi, Hitoshi; Nimer, Stephen; Mano, Hiroyuki; Naoe, Tomoki; Tomonaga, Masao; Miyazaki, Yasushi

2013-01-01

Myeloid ELF1-like factor (MEF/ELF4), a member of the ETS transcription factors, can function as an oncogene in murine cancer models and is overexpressed in various human cancers. Here, we report a mechanism by which MEF/ELF4 may be activated by a common leukemia-associated mutation in the nucleophosmin gene. By using a tandem affinity purification assay, we found that MEF/ELF4 interacts with multifactorial protein nucleophosmin (NPM1). Coimmunoprecipitation and GST pull-down experiments demonstrated that MEF/ELF4 directly forms a complex with NPM1 and also identified the region of NPM1 that is responsible for this interaction. Functional analyses showed that wild-type NPM1 inhibited the DNA binding and transcriptional activity of MEF/ELF4 on the HDM2 promoter, whereas NPM1 mutant protein (Mt-NPM1) enhanced these activities of MEF/ELF4. Induction of Mt-NPM1 into MEF/ELF4-overexpressing NIH3T3 cells facilitated malignant transformation. In addition, clinical leukemia samples with NPM1 mutations had higher human MDM2 (HDM2) mRNA expression. Our data suggest that enhanced HDM2 expression induced by mutant NPM1 may have a role in MEF/ELF4-dependent leukemogenesis. PMID:23393136

Mutations in the nucleolar phosphoprotein, nucleophosmin, promote the expression of the oncogenic transcription factor MEF/ELF4 in leukemia cells and potentiates transformation.

PubMed

Ando, Koji; Tsushima, Hideki; Matsuo, Emi; Horio, Kensuke; Tominaga-Sato, Shinya; Imanishi, Daisuke; Imaizumi, Yoshitaka; Iwanaga, Masako; Itonaga, Hidehiro; Yoshida, Shinichiro; Hata, Tomoko; Moriuchi, Ryozo; Kiyoi, Hitoshi; Nimer, Stephen; Mano, Hiroyuki; Naoe, Tomoki; Tomonaga, Masao; Miyazaki, Yasushi

2013-03-29

Myeloid ELF1-like factor (MEF/ELF4), a member of the ETS transcription factors, can function as an oncogene in murine cancer models and is overexpressed in various human cancers. Here, we report a mechanism by which MEF/ELF4 may be activated by a common leukemia-associated mutation in the nucleophosmin gene. By using a tandem affinity purification assay, we found that MEF/ELF4 interacts with multifactorial protein nucleophosmin (NPM1). Coimmunoprecipitation and GST pull-down experiments demonstrated that MEF/ELF4 directly forms a complex with NPM1 and also identified the region of NPM1 that is responsible for this interaction. Functional analyses showed that wild-type NPM1 inhibited the DNA binding and transcriptional activity of MEF/ELF4 on the HDM2 promoter, whereas NPM1 mutant protein (Mt-NPM1) enhanced these activities of MEF/ELF4. Induction of Mt-NPM1 into MEF/ELF4-overexpressing NIH3T3 cells facilitated malignant transformation. In addition, clinical leukemia samples with NPM1 mutations had higher human MDM2 (HDM2) mRNA expression. Our data suggest that enhanced HDM2 expression induced by mutant NPM1 may have a role in MEF/ELF4-dependent leukemogenesis.

EFFECTS OF ELF (EXTREMELY LOW FREQUENCY) (1-120 HZ) AND MODULATED (50 HZ) RF (RADIO FREQUENCY) FIELDS ON THE EFFLUX OF CALCIUM IONS FROM BRAIN TISSUE IN VITRO

EPA Science Inventory

The authors have previously shown that 16-Hz, sinusoidal electromagnetic fields can cause enhanced efflux of calcium ions from chick brain tissue, in vitro, in two intensity regions centered on 6 and 40 Vp-p/m. Alternatively, 1-Hz and 30-Hz fields at 40Vp-p/m did not cause enhanc...

Relationship Between Alfvenic Fluctuations and Heavy Ion Heating in the Cusp at 1 Re

NASA Technical Reports Server (NTRS)

Coffey, Victoria; Chandler, Michael; Singh, Nagendra

2008-01-01

We look at the effect of heavy ion heating from their coupling with observed broadband (BB-ELF) emissions. These wave fluctuations are common to many regions of the ionosphere and magnetosphere and have been described as spatial turbulence of dispersive Alfven waves (DAW) with short perpendicular wavelengths. With Polar passing through the cusp at 1 Re in the Spring of 1996, we show the correlation of their wave power with mass-resolved O+ derived heating rates. This relationship lead to the study of the coupling of the thermal O+ ions and these bursty electric fields. We demonstrate the role of these measurements in the suggestion of DAW and stochastic ion heating and the observed density cavity characteristics.

High-resolution observations of core and suprathermal ions in the auroral ionosphere: Techniques and results from the GEODESIC sounding rocket

NASA Astrophysics Data System (ADS)

Burchill, Johnathan Kerr

Low-energy (Ek ˜ 10-1--10 1 eV) ions comprise the bulk of Earth's ionosphere, and represent the initial stages of ion heating and outflow from Earth's auroral regions. The suprathermal ion imager (SII) is a fast (˜93 images/sec), compact, two-dimensional ion energy (0 < Ek < 20 eV) and direction-of-arrival analyzer designed to observe the energy distributions of these ions in detail, with emphasis on exploring small-scale (˜10--100 m) structure in the ionosphere. The SII was flown into an auroral substorm on the GEODESIC sounding rocket from Poker Flat, Alaska, on 26 February 2000. The technical element of this thesis deals with the development of a computer model of the SII, and techniques for extracting and interpreting physical quantities from the SII observations. Laboratory and in-flight calibrations demonstrate that the analyzer imaging capability departs from the ideal model. Nevertheless, the SII represents a technological step forward, and has yielded new scientific results. The scientific element of this thesis focuses on simultaneous observations of ion energy distributions and low-frequency plasma waves in the topside (500--1000 km) auroral ionosphere. GEODESIC encountered three types of plasma wave which have previously been associated with ion heating. However, heated ions were only observed in association with localized density depletions and wave enhancements known as lower-hybrid solitary structures (LHSS). Approximately 90% of the LHSS ion number density is comprised of the ambient isotropic sub-eV core population. The remaining 10% corresponds to transverse acceleration of ions (TAI) to within 5° transverse to the geomagnetic field and to mean energies up to 5--10 eV, consistent with previous findings. Contrary to previously published observations, the GEODESIC TAI is consistent with localized bulk heating of some of the ambient core. Ion heating was not observed in association with large-scale (>1 km) broadband extremely low frequency (BB ELF) wave enhancements. Similarly, no ion heating was detected in the presence of large amplitude, short perpendicular wavelength Alfven waves. Differences between low-frequency ion flow fluctuations and convection drift fluctuations can be explained only partially by ion polarization drift physics.

Noninvasive markers of liver fibrosis: on-treatment changes of serum markers predict the outcome of antifibrotic therapy.

PubMed

Tanwar, Sudeep; Trembling, Paul M; Hogan, Brian J; Srivastava, Ankur; Parkes, Julie; Harris, Scott; Grant, Paul; Nastouli, Eleni; Ocker, Mathias; Wehr, Klaus; Herold, Christoph; Neureiter, Daniel; Schuppan, Detlef; Rosenberg, William M

2017-03-01

The utility of noninvasive serum markers to longitudinally monitor liver fibrosis is not established. A total of 70 patients with chronic hepatitis C who had previously failed antiviral therapy were randomized to receive pegylated interferon with or without silymarin for 24 months. Enhanced Liver Fibrosis (ELF) tests (hyularonic acid, terminal peptide of procollagen III, tissue inhibitor of matrix metaloproteinase-1) were performed on patient sera obtained before, during and at the end of the study (0, 12, 24 months) and liver histology obtained before and at the end of the study. At 24 months, absolute changes in Ishak fibrosis stage and ELF ranged from -4 to +4 and from -2.41 to +2.68, respectively. Absolute changes in ELF at 12 months were significantly associated with changes in both ELF and histology at 24 months. A model combining both baseline ELF and change of ELF at 12 months could predict the 24-month ELF (R=0.609, P<1×10), a decrease in ELF at 24 months [area under the curve (AUC): 0.80-0.85] and an increase in ELF at 24 months (AUC: 0.81-0.85). Furthermore, a model combining both baseline histologic stage and ELF together with the change of ELF at 12 months could predict 24-month histology (R=0.601, P<1×10, AUC: 0.88-0.92), histologic fibrosis regression (AUC: 0.81-0.84) and progression (AUC: 0.86-0.91). Our observations suggest that a change in the serum marker ELF predicts changes in liver fibrosis over a longer period. These data support the use of ELF as a surrogate marker of liver fibrosis evolution in monitoring antifibrotic treatments, thus permitting 'response-guided' therapy by the early identification of patients who will benefit from prolonged treatment.

Differentiation of K562 cells under ELF-EMF applied at different time courses.

PubMed

Ayşe, Inhan-Garip; Zafer, Akan; Sule, Oncul; Işil, Işal-Turgut; Kalkan, Tunaya

2010-08-01

The time-course of ELF-EMF application to biological systems is thought to be an important parameter determining the physiological outcome. This study investigated the effect of ELF-EMF on the differentiation of K562 cells at different time courses. ELF-EMF (50 Hz, 5 mT, 1 h) was applied at two different time-courses; first at the onset of hemin induction for 1 h, and second, daily 1 h for four days. While single exposure to ELF-EMF resulted in a decrease in differentiation, ELF-EMF applied everyday for 1 h caused an increase in differentiation. The effect of co-stressors, magnesium, and heat-shock was also determined and similar results were obtained. ELF-EMF increased ROS levels in K562 cells not treated with hemin, however did not change ROS levels of hemin treated cells indicating that ROS was not the cause. Overall, these results imply that the time-course of application is an important parameter determining the physiological response of cells to ELF-EMF.

Anomalous Signal Detection in ELF Band Electromagnetic Wave using Multi-layer Neural Network with Wavelet Decomposition

NASA Astrophysics Data System (ADS)

Itai, Akitoshi; Yasukawa, Hiroshi; Takumi, Ichi; Hata, Masayasu

It is well known that electromagnetic waves radiated from the earth's crust are useful for predicting earthquakes. We analyze the electromagnetic waves received at the extremely low frequency band of 223Hz. These observed signals contain the seismic radiation from the earth's crust, but also include several undesired signals. Our research focuses on the signal detection technique to identify an anomalous signal corresponding to the seismic radiation in the observed signal. Conventional anomalous signal detections lack a wide applicability due to their assumptions, e.g. the digital data have to be observed at the same time or the same sensor. In order to overcome the limitation related to the observed signal, we proposed the anomalous signals detection based on a multi-layer neural network which is trained by digital data observed during a span of a day. In the neural network approach, training data do not need to be recorded at the same place or the same time. However, some noises, which have a large amplitude, are detected as the anomalous signal. This paper develops a multi-layer neural network to decrease the false detection of the anomalous signal from the electromagnetic wave. The training data for the proposed network is the decomposed signal of the observed signal during several days, since the seismic radiations are often recorded from several days to a couple of weeks. Results show that the proposed neural network is useful to achieve the accurate detection of the anomalous signal that indicates seismic activity.

Influence of the on-line ELF-EMF stimulation on the electrophysiological properties of the rat hippocampal CA1 neurons in vitro

NASA Astrophysics Data System (ADS)

Zheng, Yu; Ma, Wei; Dong, Lei; Dou, Jun-rong; Gao, Yang; Xue, Jing

2017-10-01

The extremely low frequency electromagnetic fields (ELF-EMFs) have been shown to have an environmentally negative effect on humans' health; however, its treatment effect is beneficial for patients suffering from neurological disorders. Despite this success, the application of ELF-EMF has exceeded in the understanding of its internal mechanism. Recently, it was found that on-line magnetic stimulation may offer advantages over off-line magnetic exposure and has proven to be effective in activating the prefrontal cortex pyramidal neurons in vitro. Here, we perform computational simulations of the stimulation coils in COMSOL modeling to describe the uniformity of the distribution of the on-line magnetic field. Interestingly, the modeling data and actual measurements showed that the densities of the magnetic flux that was generated by the on-line stimulation coils were similar. The on-line magnetic stimulator induced sodium channel currents as well as field excitatory postsynaptic potentials of the rat hippocampal CA1 neurons and successfully demonstrated its extensive applications to activate neuronal tissue. These findings further raise the possibility that the instrument of on-line magnetic stimulation may be an effective alternative for studies in the field of bioelectromagnetics.

Novel exposure units for at-home personalized testing of electromagnetic sensibility.

PubMed

Huss, Anke; Murbach, Manuel; van Moorselaar, Imke; Kuster, Niels; van Strien, Rob; Kromhout, Hans; Vermeulen, Roel; Slottje, Pauline

2016-01-01

Previous experimental studies on electromagnetic hypersensitivity have been criticized regarding inflexibility of choice of exposure and of study locations. We developed and tested novel portable exposure units that can generate different output levels of various extremely low frequency magnetic fields (ELF-MF; 50 Hz field plus harmonics) and radiofrequency electromagnetic fields (RF-EMF). Testing was done with a group of healthy volunteers (n = 25 for 5 ELF-MF and n = 25 for 5 RF-EMF signals) to assess if units were indeed able to produce double-blind exposure conditions. Results substantiated that double-blind conditions were met; on average participants scored 50.6% of conditions correct on the ELF-MF, and 50.0% on the RF-EMF unit, which corresponds to guessing probability. No cues as to exposure conditions were reported. We aim to use these units in a future experiment with subjects who wish to test their personal hypothesis of being able to sense or experience when being exposed to EMF. The new units allow for a high degree of flexibility regarding choice of applied electromagnetic signal, output power level and location (at home or another environment of subjects' choosing). © 2015 Wiley Periodicals, Inc.

Background ELF magnetic fields in incubators: a factor of importance in cell culture work.

PubMed

Mild, Kjell Hansson; Wilén, Jonna; Mattsson, Mats-Olof; Simko, Myrtill

2009-07-01

Extremely low frequency (ELF) magnetic fields in cell culture incubators have been measured. Values of the order of tens of muT were found which is in sharp contrast to the values found in our normal environment (0.05-0.1microT). There are numerous examples of biological effects found after exposure to MF at these levels, such as changes in gene expression, blocked cell differentiation, inhibition of the effect of tamoxifen, effects on chick embryo development, etc. We therefore recommend that people working with cell culture incubators check for the background magnetic field and take this into account in performing their experiments, since this could be an unrecognised factor of importance contributing to the variability in the results from work with cell cultures.

Pre-exposure to 50 Hz magnetic fields modifies menadione-induced genotoxic effects in human SH-SY5Y neuroblastoma cells.

PubMed

Luukkonen, Jukka; Liimatainen, Anu; Höytö, Anne; Juutilainen, Jukka; Naarala, Jonne

2011-03-23

Extremely low frequency (ELF) magnetic fields (MF) are generated by power lines and various electric appliances. They have been classified as possibly carcinogenic by the International Agency for Research on Cancer, but a mechanistic explanation for carcinogenic effects is lacking. A previous study in our laboratory showed that pre-exposure to ELF MF altered cancer-relevant cellular responses (cell cycle arrest, apoptosis) to menadione-induced DNA damage, but it did not include endpoints measuring actual genetic damage. In the present study, we examined whether pre-exposure to ELF MF affects chemically induced DNA damage level, DNA repair rate, or micronucleus frequency in human SH-SY5Y neuroblastoma cells. Exposure to 50 Hz MF was conducted at 100 µT for 24 hours, followed by chemical exposure for 3 hours. The chemicals used for inducing DNA damage and subsequent micronucleus formation were menadione and methyl methanesulphonate (MMS). Pre-treatment with MF enhanced menadione-induced DNA damage, DNA repair rate, and micronucleus formation in human SH-SY5Y neuroblastoma cells. Although the results with MMS indicated similar effects, the differences were not statistically significant. No effects were observed after MF exposure alone. The results confirm our previous findings showing that pre-exposure to MFs as low as 100 µT alters cellular responses to menadione, and show that increased genotoxicity results from such interaction. The present findings also indicate that complementary data at several chronological points may be critical for understanding the MF effects on DNA damage, repair, and post-repair integrity of the genome.

Maternal residential proximity to sources of extremely low frequency electromagnetic fields and adverse birth outcomes in a UK cohort.

PubMed

de Vocht, Frank; Hannam, Kimberly; Baker, Philip; Agius, Raymond

2014-04-01

Studies have suggested that exposure to extremely low frequency electromagnetic fields (ELF-EMF) may be associated with increased risk of adverse birth outcomes. This study tested the hypothesis that close proximity to residential ELF-EMF sources is associated with a reduction in birth weight and increased the risk of low birthweight (LBW), small for gestational age (SGA) and spontaneous preterm birth (SPTB). Closest residential proximity to high voltage cables, overhead power lines, substations or towers during pregnancy was calculated for 140356 singleton live births between 2004 and 2008 in Northwest England. Associations between proximity and risk for LBW, SGA and SPTB were calculated, as well as associations with birth weight directly. Associations were adjusted for maternal age, ethnicity, parity and for part of the population additionally for maternal smoking during pregnancy. Reduced average birth weight of 212 g (95% confidence interval (CI): -395 to -29 g) was found for close proximity to a source, and was largest for female births (-251 g (95% CI: -487 to -15 g)). No statistically significant increased risks for any clinical birth outcomes with residential proximity of 50 m or less were observed. Living close (50 m or less) to a residential ELF-EMF source during pregnancy is associated with suboptimal growth in utero, with stronger effects in female than in males. However, only a few pregnant women live this close to high voltage cables, overhead power lines, substations or towers, likely limiting its public health impact. © 2014 Wiley Periodicals, Inc.

ELF5 Drives Lung Metastasis in Luminal Breast Cancer through Recruitment of Gr1+ CD11b+ Myeloid-Derived Suppressor Cells.

PubMed

Gallego-Ortega, David; Ledger, Anita; Roden, Daniel L; Law, Andrew M K; Magenau, Astrid; Kikhtyak, Zoya; Cho, Christina; Allerdice, Stephanie L; Lee, Heather J; Valdes-Mora, Fatima; Herrmann, David; Salomon, Robert; Young, Adelaide I J; Lee, Brian Y; Sergio, C Marcelo; Kaplan, Warren; Piggin, Catherine; Conway, James R W; Rabinovich, Brian; Millar, Ewan K A; Oakes, Samantha R; Chtanova, Tatyana; Swarbrick, Alexander; Naylor, Matthew J; O'Toole, Sandra; Green, Andrew R; Timpson, Paul; Gee, Julia M W; Ellis, Ian O; Clark, Susan J; Ormandy, Christopher J

2015-12-01

During pregnancy, the ETS transcription factor ELF5 establishes the milk-secreting alveolar cell lineage by driving a cell fate decision of the mammary luminal progenitor cell. In breast cancer, ELF5 is a key transcriptional determinant of tumor subtype and has been implicated in the development of insensitivity to anti-estrogen therapy. In the mouse mammary tumor virus-Polyoma Middle T (MMTV-PyMT) model of luminal breast cancer, induction of ELF5 levels increased leukocyte infiltration, angiogenesis, and blood vessel permeability in primary tumors and greatly increased the size and number of lung metastasis. Myeloid-derived suppressor cells, a group of immature neutrophils recently identified as mediators of vasculogenesis and metastasis, were recruited to the tumor in response to ELF5. Depletion of these cells using specific Ly6G antibodies prevented ELF5 from driving vasculogenesis and metastasis. Expression signatures in luminal A breast cancers indicated that increased myeloid cell invasion and inflammation were correlated with ELF5 expression, and increased ELF5 immunohistochemical staining predicted much shorter metastasis-free and overall survival of luminal A patients, defining a group who experienced unexpectedly early disease progression. Thus, in the MMTV-PyMT mouse mammary model, increased ELF5 levels drive metastasis by co-opting the innate immune system. As ELF5 has been previously implicated in the development of antiestrogen resistance, this finding implicates ELF5 as a defining factor in the acquisition of the key aspects of the lethal phenotype in luminal A breast cancer.

ELF5 Drives Lung Metastasis in Luminal Breast Cancer through Recruitment of Gr1+ CD11b+ Myeloid-Derived Suppressor Cells

PubMed Central

Gallego-Ortega, David; Ledger, Anita; Roden, Daniel L.; Law, Andrew M. K.; Magenau, Astrid; Kikhtyak, Zoya; Cho, Christina; Allerdice, Stephanie L.; Lee, Heather J.; Valdes-Mora, Fatima; Herrmann, David; Salomon, Robert; Young, Adelaide I. J.; Lee, Brian Y.; Sergio, C. Marcelo; Kaplan, Warren; Piggin, Catherine; Conway, James R. W.; Rabinovich, Brian; Millar, Ewan K. A.; Oakes, Samantha R.; Chtanova, Tatyana; Swarbrick, Alexander; Naylor, Matthew J.; O’Toole, Sandra; Green, Andrew R.; Timpson, Paul; Gee, Julia M. W.; Ellis, Ian O.; Clark, Susan J.; Ormandy, Christopher J.

2015-01-01

During pregnancy, the ETS transcription factor ELF5 establishes the milk-secreting alveolar cell lineage by driving a cell fate decision of the mammary luminal progenitor cell. In breast cancer, ELF5 is a key transcriptional determinant of tumor subtype and has been implicated in the development of insensitivity to anti-estrogen therapy. In the mouse mammary tumor virus-Polyoma Middle T (MMTV-PyMT) model of luminal breast cancer, induction of ELF5 levels increased leukocyte infiltration, angiogenesis, and blood vessel permeability in primary tumors and greatly increased the size and number of lung metastasis. Myeloid-derived suppressor cells, a group of immature neutrophils recently identified as mediators of vasculogenesis and metastasis, were recruited to the tumor in response to ELF5. Depletion of these cells using specific Ly6G antibodies prevented ELF5 from driving vasculogenesis and metastasis. Expression signatures in luminal A breast cancers indicated that increased myeloid cell invasion and inflammation were correlated with ELF5 expression, and increased ELF5 immunohistochemical staining predicted much shorter metastasis–free and overall survival of luminal A patients, defining a group who experienced unexpectedly early disease progression. Thus, in the MMTV-PyMT mouse mammary model, increased ELF5 levels drive metastasis by co-opting the innate immune system. As ELF5 has been previously implicated in the development of antiestrogen resistance, this finding implicates ELF5 as a defining factor in the acquisition of the key aspects of the lethal phenotype in luminal A breast cancer. PMID:26717410

Evaluation of occupational exposure to ELF magnetic fields at power plants in Greece in the context of European directives.

PubMed

Christopoulou, Maria; Govari, Chrysa; Tsaprouni, Panagiota; Karabetsos, Efthymios

2015-12-01

The scope of this paper is to comparatively present the extremely low-frequency (ELF) measurements performed at four power plants in Greece, focusing on: (a) the worst-case exposure conditions, (b) the existence of magnetic field harmonic components, (c) the technical similarities among the power plants and (d) comparison of the measured percentages of reference levels at typical working areas in the power plants. A detailed measurement methodology is proposed, including broadband on-site inspection of the working areas, weighted averaged root-mean-square and peak values of magnetic flux density, percentage of reference levels, according to 1998 ICNIRP guidelines and harmonic analysis of the multi-frequency magnetic fields. During the analysis of the occupational exposure in all power plants, the new Directive 2013/35/EU has been taken into account. The study concludes by proposing a mapping procedure of working areas into certain zones, in order to take measures for workers safety. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The Ets transcription factor Elf5 specifies mammary alveolar cell fate

PubMed Central

Oakes, Samantha R.; Naylor, Matthew J.; Asselin-Labat, Marie-Liesse; Blazek, Katrina D.; Gardiner-Garden, Margaret; Hilton, Heidi N.; Kazlauskas, Michael; Pritchard, Melanie A.; Chodosh, Lewis A.; Pfeffer, Peter L.; Lindeman, Geoffrey J.; Visvader, Jane E.; Ormandy, Christopher J.

2008-01-01

Hormonal cues regulate mammary development, but the consequent transcriptional changes and cell fate decisions are largely undefined. We show that knockout of the prolactin-regulated Ets transcription factor Elf5 prevented formation of the secretory epithelium during pregnancy. Conversely, overexpression of Elf5 in an inducible transgenic model caused alveolar differentiation and milk secretion in virgin mice, disrupting ductal morphogenesis. CD61+ luminal progenitor cells accumulated in Elf5-deficient mammary glands and were diminished in glands with Elf5 overexpression. Thus Elf5 specifies the differentiation of CD61+ progenitors to establish the secretory alveolar lineage during pregnancy, providing a link between prolactin, transcriptional events, and alveolar development. PMID:18316476

Beyond ENL Norms in ELF Use: A Cognitive Perspective on ELF Output

ERIC Educational Resources Information Center

Alptekin, Cem

2011-01-01

This article presents a cognitively-oriented account of the qualitative differences between ENL (English as a native language) and ELF (English as a lingua franca) users. Based on the declarative-procedural model of second language acquisition, it examines the linguistic and sociolinguistic implications of ELF users' dependence on their…

Roles and regulations of the ETS transcription factor ELF4/MEF

PubMed Central

Suico, Mary Ann; Shuto, Tsuyoshi; Kai, Hirofumi

2017-01-01

Abstract Most E26 transformation-specific (ETS) transcription factors are involved in the pathogenesis and progression of cancer. This is in part due to the roles of ETS transcription factors in basic biological processes such as growth, proliferation, and differentiation, and also because of their regulatory functions that have physiological relevance in tumorigenesis, immunity, and basal cellular homoeostasis. A member of the E74-like factor (ELF) subfamily of the ETS transcription factor family—myeloid elf-1-like factor (MEF), designated as ELF4—has been shown to be critically involved in immune response and signalling, osteogenesis, adipogenesis, cancer, and stem cell quiescence. ELF4 carries out these functions as a transcriptional activator or through interactions with its partner proteins. Mutations in ELF4 cause aberrant interactions and induce downstream processes that may lead to diseased cells. Knowing how ELF4 impinges on certain cellular processes and how it is regulated in the cells can lead to a better understanding of the physiological and pathological consequences of modulated ELF4 activity. PMID:27932483

mTOR Activation by PI3K/Akt and ERK Signaling in Short ELF-EMF Exposed Human Keratinocytes

PubMed Central

Patruno, Antonia; Pesce, Mirko; Grilli, Alfredo; Speranza, Lorenza; Franceschelli, Sara; De Lutiis, Maria Anna; Vianale, Giovina; Costantini, Erica; Amerio, Paolo; Muraro, Raffaella; Felaco, Mario; Reale, Marcella

2015-01-01

Several reports suggest that ELF-EMF exposures interact with biological processes including promotion of cell proliferation. However, the molecular mechanisms by which ELF-EMF controls cell growth are not completely understood. The present study aimed to investigate the effect of ELF-EMF on keratinocytes proliferation and molecular mechanisms involved. Effect of ELF-EMF (50 Hz, 1 mT) on HaCaT cell cycle and cells growth and viability was monitored by FACS analysis and BrdU assay. Gene expression profile by microarray and qRT-PCR validation was performed in HaCaT cells exposed or not to ELF-EMF. mTOR, Akt and MAPKs expressions were evaluated by Western blot analysis. In HaCaT cells, short ELF-EMF exposure modulates distinct patterns of gene expression involved in cell proliferation and in the cell cycle. mTOR activation resulted the main molecular target of ELF-EMF on HaCaT cells. Our data showed the increase of the canonical pathway of mTOR regulation (PI3K/Akt) and activation of ERK signaling pathways. Our results indicate that ELF-EMF selectively modulated the expression of multiple genes related to pivotal biological processes and functions that play a key role in physio-pathological mechanisms such as wound healing. PMID:26431550

Differential requirements for the Ets transcription factor Elf-1 in the development of NKT cells and NK cells

PubMed Central

Choi, Hak-Jong; Geng, Yanbiao; Cho, Hoonsik; Li, Sha; Giri, Pramod Kumar; Felio, Kyrie

2011-01-01

E26 Transformation specific (Ets) family transcription factors control the expression of a large number of genes regulating hematopoietic cell development and function. Two such transcription factors, Ets-1 and myeloid Elf-1–like factor (MEF), have been shown to play critical roles in both natural killer (NK)– and NKT-cell development, but not in the development of conventional T cells. In this study, we address the role of E74-like factor 1 (Elf-1), another Ets family transcription factor that is closely related to MEF but divergent from Ets-1, in NK- and NKT-cell development using Elf-1–deficient (Elf-1−/−) mice. Whereas the proportion of NK cells in Elf-1−/− mice was normal, the proportion of NKT cells was significantly reduced in the thymus and periphery of Elf-1−/− mice compared with wild-type (WT) mice. Although Ets-1–deficient mice lack NKT cells altogether, Elf-1−/− mice exhibited only a partial block in NKT-cell development caused by a cell-intrinsic defect in the selection, survival, and maturation of NKT cells. In addition, residual NKT cells found in Elf-1−/− mice produced less cytokine upon antigen stimulation compared with WT NKT cells. Our data demonstrate that Elf-1 plays an important and nonredundant role in the development and function of NKT cells, but is not involved in NK-cell development. PMID:21148815

Experimental model for ELF-EMF exposure: Concern for human health

PubMed Central

D’Angelo, C.; Costantini, E.; Kamal, M.A.; Reale, M.

2014-01-01

Low frequency (LF) electromagnetic fields (EMFs) are abundantly present in modern society and in the last 20 years the interest about the possible effect of extremely low frequency (ELF) EMFs on human health has increased progressively. Epidemiological studies, designed to verify whether EMF exposure may be a potential risk factor for health, have led to controversial results. The possible association between EMFs and an increased incidence of childhood leukemia, brain tumors or neurodegenerative diseases was not fully elucidated. On the other hand, EMFs are widely used, in neurology, psychiatry, rheumatology, orthopedics and dermatology, both in diagnosis and in therapy. In vitro studies may help to evaluate the mechanism by which LF-EMFs affect biological systems. Invitro model of wound healing used keratinocytes (HaCaT), neuroblastoma cell line (SH-SY5Y) as a model for analysis of differentiation, metabolism and functions related to neurodegenerative processes, and monocytic cell line (THP-1) was used as a model for inflammation and cytokines production, while leukemic cell line (K562) was used as a model for hematopoietic differentiation. MCP-1, a chemokine that regulates the migration and infiltration of memory T cells, natural killer (NK), monocytes and epithelial cells, has been demonstrated to be induced and involved in various diseases. Since, varying the parameters of EMFs different effects may be observed, we have studied MCP-1 expression in HaCaT, SH-SY5Y, THP-1 and K562 exposed to a sinusoidal EMF at 50 Hz frequency with a flux density of 1 mT (rms). Our preliminary results showed that EMF-exposure differently modifies the expression of MCP-1 in different cell types. Thus, the MCP-1 expression needs to be better determined, with additional studies, with different parameters and times of exposure to ELF-EMF. PMID:25561888

Theoretical investigation of EM wave generation and radiation in the ULF, ELF, and VLF bands by the electrodynamic orbiting tether

NASA Technical Reports Server (NTRS)

Estes, Robert D.; Grossi, Mario D.

1989-01-01

The problem of electromagnetic wave generation by an electrodynamic tethered satellite system is important both for the ordinary operation of such systems and for their possible application as orbiting transmitters. The tether's ionospheric circuit closure problem is closely linked with the propagation of charge-carrying electromagnetic wave packets away from the tethered system. Work is reported which represents a step towards a solution to the problem that takes into account the effects of boundaries and of vertical variations in plasma density, collision frequencies, and ion species. The theory of Alfen wave packet generation by an electrodynamic tethered system in an infinite plasma medium is reviewed, and brief summary of previous work on the problem is given. The consequences of the presence of the boundaries and the vertical nonuniformity are then examined. One of the most significant new features to emerge when ion-neutral collisions are taken into account is the coupling of the Alfven waves to the fast magnetosonic wave. This latter wave is important, as it may be confined by vertical variations in the Alfven speed to a sort of leaky ionospheric wave guide, the resonances of which could be of great importance to the signal received on the Earth's surface. The infinite medium solution for this case where the (uniform) geomagnetic field makes an arbitrary angle with the vertical is taken as the incident wave-packet. Even without a full solution, a number of conclusions can be drawn, the most important of which may be that the electromagnetic field associated with the operation of a steady-current tethered system will probably be too weak to detect on the Earth's surface, even for large tethered currents. This is due to the total reflection of the incident wave at the atmospheric boundary and the inability of a steady-current tethered system to excite the ionospheric wave-guide. An outline of the approach to the numerical problem is given. The use of numerical integrations and boundary conditions consistent with a conducting Earth is proposed to obtain the solution for the horizontal electromagnetic field components at the boundary of the ionosphere with the atmospheric cavity.

English as a Lingua Franca: Ontology and Ideology

ERIC Educational Resources Information Center

Sewell, Andrew

2013-01-01

This article examines certain aspects of the debate surrounding English as a Lingua Franca (ELF). It argues that in some ways, neither ELF nor its opponents have come to terms with the complexities of English in a globalized world. By defining ELF according to how it differs from native-speaker language use, ELF researchers have tended to…

On the distribution of the amplitudes of natural ELF emissions from measurements on the Kola peninsula.

NASA Astrophysics Data System (ADS)

Pchelkin, Vladimir; Beloglazov, Mikhail

The distributions of the amplitudes of natural emissions of electromagnetic field in the Shu-mann resonance frequency range are investigated. From the data of Lovozero observatory daily variations of the number of overshoots of signal amplitude above given thresholds were con-structed. A possibility is discussed of applicability for the considered frequency range a known from the literature formula, which describes analytically the peak distribution of the spherics. We note the influence of magnetic disturbances on amplitude distribution function.

Extremely Low Frequency (ELF) Communications Program Non-Ionizing Electromagnetic Radiation Literature Evaluation and Assessment; 1977-1986 Literature Review.

DTIC Science & Technology

1986-11-01

Napoli, Italy, who tested the possible chromosomal abnormalities caused by a 50-Hz electric field. Bovine lymphocytes from peripheral blood were cultured...production, ’. mastitis , etc. The problem can be mitigated by improved grounding practices on farmsteads, and it is not directly relevant to ELFCSs. The

What Message Should Health Educators Give regarding Electromagnetic Fields?

ERIC Educational Resources Information Center

Al-Khamees, Nedaa A.

2008-01-01

The possibility of extremely low frequency electromagnetic fields (ELF EMF) causing a number of medical conditions and common symptoms remains a concern and presents somewhat of a quandary to health educators in view of conflicting results. This study investigated the relationship of a number of EMF sources to reported symptoms in an attempt to,…

The European Location Framework - from National to European

NASA Astrophysics Data System (ADS)

Pauknerova, E.; Sidlichovsky, P.; Urbanas, S.; Med, M.

2016-06-01

The European Location Framework (ELF) means a technical infrastructure which will deliver authoritative, interoperable geospatial reference data from all over Europe for analysing and understanding information connected to places and features. The ELF has been developed and set up through the ELF Project, which has been realized by a consortium of partners (public, private and academic organisations) since March 2013. Their number increased from thirty to forty in the year 2016, together with a project extension from 36 to 44 months. The project is co-funded by the European Commission's Competitiveness and Innovation Framework Programme (CIP) and will end in October 2016. In broad terms, the ELF Project will deliver a unique gateway to the authoritative reference geospatial information for Europe (harmonised pan-European maps, geographic and land information) sourced from the National Mapping and Cadastral Authorities (NMCAs) around Europe and including transparent licensing. This will be provided as an online ELF web service that will deliver an up-to-date topographic base map and also as view & download services for access to the ELF datasets. To develop and build up the ELF, NMCAs are accompanied and collaborate with several research & academia institutes, a standardisation body, system integrators, software developers and application providers. The harmonisation is in progress developing and triggering a number of geo-tools like edge-matching, generalisation, transformation and others. ELF will provide also some centralised tools like Geo Locator for searching location based on geographical names, addresses and administrative units, and GeoProduct Finder for discovering the available web-services and licensing them. ELF combines national reference geo-information through the ELF platform. ELF web services will be offered to users and application developers through open source (OSKARI) and proprietary (ArcGIS Online) cloud platforms. Recently, 29 NMCAs plus the EuroGeographics - their pan-European umbrella association, contribute to the ELF through an enrichment of data coverage. As a result, over 20 European countries will be covered with the ELF topo Base Map in 2016. Most countries will contribute also with other harmonized thematic data for viewing or down-loading. To overcome the heterogeneity of data resources and diversity of languages in tens of European countries, ELF builds on the existing INSPIRE rules and its own coordination and interoperability measures. ELF realisation empowers the implementation of INSPIRE in Europe and it complements related activities of European NMCAs, e.g. Czech Office for Surveying, Mapping and Cadastre (CUZK), which provides a large portfolio of spatial data/services and contributes significantly to the NSDI of Czech Republic. CUZK is also responsible for the Base Register of Territorial Identification, Addresses and Real Estates (RUIAN) - an important pillar of Czech e-Government. CUZK became an early-bird in implementing INSPIRE and it provides to the ELF a number of compliant datasets and web services. CUZK and the Polish NMCA (GUGiK) collaborate in the Central-European ELF Pilot (cluster) and test various cross-border prototypes. The presentation combines the national and crossborder view and experiences of CUZK and the European perspective of EuroGeographics.

Ways to Use ICT in Schools to Optimize the Impact on Teaching and Learning

ERIC Educational Resources Information Center

Fredriksson, Ulf; Gajek, Elzbieta; Jedeskog, Gunilla

2009-01-01

The European eLearning Forum for Education 2 (ELFE2) is a project initiated by the ETUCE (European Trade Union Committee on Education) and builds on the conclusion of its predecessor ELFE1. ELFE2 aims, as ELFE1, to contribute to a better understanding of the strengths and weaknesses of using ICT in education. It identifies ways used to optimize…

Kinetic multi-layer model of the epithelial lining fluid (KM-ELF): Reactions of ozone and OH with antioxidants and surfactant molecules

NASA Astrophysics Data System (ADS)

Lakey, Pascale; Pöschl, Ulrich; Shiraiwa, Manabu

2015-04-01

Oxidants cause damage to biosurfaces such as the lung epithelium unless they are effectively scavenged. The respiratory tract is covered in a thin layer of fluid which extends from the nasal cavity to the alveoli and contain species that scavenge ozone and other incoming oxidants. The kinetic multi-layer model of the epithelial lining fluid (KM-ELF) has been developed in order to investigate the reactions of ozone and OH with antioxidants (ascorbate, uric acid, glutathione and α-tocopherol) and surfactant lipids and proteins within the epithelial lining fluid (ELF). The model incorporates different processes: gas phase diffusion, adsorption and desorption from the surface, bulk phase diffusion and known reactions at the surface and in the bulk. The ELF is split into many layers: a sorption layer, a surfactant layer, a near surface bulk layer and several bulk layers. Initial results using KM-ELF indicate that at ELF thicknesses of 80 nm and 1 × 10-4cm the ELF would become rapidly saturated with ozone with saturation occurring in less than a second. However, at an ELF thickness of 1 × 10-3cm concentration gradients were observed throughout the ELF and the presence of antioxidants reduced the O3 reaching the lung cells and tissues by 40% after 1 hour of exposure. In contrast, the antioxidants were efficient scavengers of OH radicals, although the large rate constants of OH reacting with the antioxidants resulted in the antioxidants decaying away rapidly. The chemical half-lives of the antioxidants and surface species were also calculated using KM-ELF as a function of O3 and OH concentration and ELF thickness. Finally, the pH dependence of the products of reactions between antioxidants and O3 were investigated. The KM-ELF model predicted that a harmful ascorbate ozonide product would increase from 1.4 × 1011cm-3at pH 7.4 to 1.1 × 1014 cm-3 at pH 4after 1 hour although a uric acid ozonide product would decrease from 2.0 × 1015cm-3to 5.9 × 1012cm-3.

Pre-Exposure to 50 Hz Magnetic Fields Modifies Menadione-Induced Genotoxic Effects in Human SH-SY5Y Neuroblastoma Cells

PubMed Central

Luukkonen, Jukka; Liimatainen, Anu; Höytö, Anne; Juutilainen, Jukka; Naarala, Jonne

2011-01-01

Background Extremely low frequency (ELF) magnetic fields (MF) are generated by power lines and various electric appliances. They have been classified as possibly carcinogenic by the International Agency for Research on Cancer, but a mechanistic explanation for carcinogenic effects is lacking. A previous study in our laboratory showed that pre-exposure to ELF MF altered cancer-relevant cellular responses (cell cycle arrest, apoptosis) to menadione-induced DNA damage, but it did not include endpoints measuring actual genetic damage. In the present study, we examined whether pre-exposure to ELF MF affects chemically induced DNA damage level, DNA repair rate, or micronucleus frequency in human SH-SY5Y neuroblastoma cells. Methodology/Principal Findings Exposure to 50 Hz MF was conducted at 100 µT for 24 hours, followed by chemical exposure for 3 hours. The chemicals used for inducing DNA damage and subsequent micronucleus formation were menadione and methyl methanesulphonate (MMS). Pre-treatment with MF enhanced menadione-induced DNA damage, DNA repair rate, and micronucleus formation in human SH-SY5Y neuroblastoma cells. Although the results with MMS indicated similar effects, the differences were not statistically significant. No effects were observed after MF exposure alone. Conclusions The results confirm our previous findings showing that pre-exposure to MFs as low as 100 µT alters cellular responses to menadione, and show that increased genotoxicity results from such interaction. The present findings also indicate that complementary data at several chronological points may be critical for understanding the MF effects on DNA damage, repair, and post-repair integrity of the genome. PMID:21448285

The impact of extremely low frequency electromagnetic fields on stream periphyton: An eleven-year study

USGS Publications Warehouse

Burton, T.M.; Uzarski, D.G.; Stelzer, R.S.; Eggert, S.L.; Sobczak, W.V.; Mullen, D.M.

2000-01-01

Potential effects of extremely low frequency (ELF) electromagnetic fields on periphyton were studied from 1983 to 1993 using a Before, After, Control and Impact design. The study was conducted at two sites on the Ford River, a fourth-order brown water trout stream in Dickinson County, Michigan. The Reference site received 4.9-6.5 times less exposure to ground electric fields and from 300 to 334 times less exposure to magnetic flux from 1989 to 1993 when the antenna was operational at 76 Hz than did the Antenna site. The objective of the study was to determine if ELF electromagnetic fields had caused changes in structure and/or function of algal communities in the Ford River. Significant differences in chlorophyll a standing crop and daily accumulation rate (a surrogate for primary productivity), and organic matter standing crop and daily accumulation rate were observed between the Reference and Antenna site after the antenna became operational. These four related community function variables all increased at the Antenna site with largest and most consistent increases occurring for chlorophyll measures. Compared to pre-operational data, the increase in chlorophyll at the Antenna site also occurred during a period of low amperage testing in 1986-1988, and did not increase further when the antenna became fully operational in 1989, indicating a low threshold for response. There was no significant differences between the Antenna and Reference sites in community structure variables such as diversity, evenness and the relative abundance of dominant diatoms. Thus, 76 Hz ELF electromagnetic radiation apparently did not change the basic makeup of the diatom community but did increase accumulation rates and standing crops of chlorophyll a and organic matter.

On Estimation Strategies in an Inverse ELF Problem

NASA Astrophysics Data System (ADS)

Mushtak, Vadim; Williams, Earle; Boldi, Robert; Nagy, Tamas

2010-05-01

Since 1965 when Balser and Wagner, the pioneer ELF experimentalists, noticed the reflection of the properties of global lightning activity in their measurements, one of the most important and challenging tasks in the ELF research is the monitoring of the world-wide lightning activity from observations in the Schumann resonance (SR) frequency range (5 to about 40 Hz). Known attempts in this direction have been undertaken using a simplified theory of ELF propagation in a spherically symmetrical Earth-ionosphere cavity. Yet numerical simulations with more realistic ELF techniques show that incorporating into the theory the cavity's major asymmetry, the day/night one, not only improves the accuracy of the monitoring procedure, but also enhances its efficiency. The reason is that the presence of asymmetries provides - via the positions of sources and observer relative not only to each other, but also to the day/night terminator, - additional "dimensions" to the task in comparison with the symmetrical case, which, in its turn, improves the convergence of the inversion procedure. The realization of the theoretically achievable efficiency of such an inversion with real SR data depends critically on the quality of measurements. After collecting and analyzing ELF data from SR stations in various regions of the globe, it was found that even under seemingly most favorable experimental conditions the SR characteristics directly estimated from ELF observations rarely have a quality acceptable for use in the inversion. A three-stage rectifying algorithm has been developed and tested in the inversion procedure. In the first stage, the data - in the form of time series, - instead of being directly Fourier-transformed for estimating the SR characteristics, are divided into shorter segments, and histograms of the segments' energy content (EC) are considered for revealing the possible presence of various interferences and the "non-systematic" (i.e. not incorporated into the source model) components. On the basis of statistical properties of the EC histograms, "credibility diagrams" - the SR characteristics vs. the segments' EC threshold - are being computed and analyzed, the characteristics' stability (respectively, instability) with the threshold being an indicator of low (respectively, high) presence of the interference/non-systematic constituent. If the diagrams are not stable enough, a more detailed analysis is being carried out in the third stage for revealing and eliminating as far as possible the instability's cause. The efficiency of the rectifying procedure is demonstrated via an improved convergence of the inversion procedure with real-world data from a global network of SR stations in Europe, North America, Asia, and Antarctica. The authors are grateful to all the SR investigators who have provided their observations for use in this study.

Indoor transformer stations and ELF magnetic field exposure: use of transformer structural characteristics to improve exposure assessment.

PubMed

Okokon, Enembe Oku; Roivainen, Päivi; Kheifets, Leeka; Mezei, Gabor; Juutilainen, Jukka

2014-01-01

Previous studies have shown that populations of multiapartment buildings with indoor transformer stations may serve as a basis for improved epidemiological studies on the relationship between childhood leukaemia and extremely-low-frequency (ELF) magnetic fields (MFs). This study investigated whether classification based on structural characteristics of the transformer stations would improve ELF MF exposure assessment. The data included MF measurements in apartments directly above transformer stations ("exposed" apartments) in 30 buildings in Finland, and reference apartments in the same buildings. Transformer structural characteristics (type and location of low-voltage conductors) were used to classify exposed apartments into high-exposure (HE) and intermediate-exposure (IE) categories. An exposure gradient was observed: both the time-average MF and time above a threshold (0.4 μT) were highest in the HE apartments and lowest in the reference apartments, showing a statistically significant trend. The differences between HE and IE apartments, however, were not statistically significant. A simulation exercise showed that the three-category classification did not perform better than a two-category classification (exposed and reference apartments) in detecting the existence of an increased risk. However, data on the structural characteristics of transformers is potentially useful for evaluating exposure-response relationship.

The Enhanced liver fibrosis score is associated with clinical outcomes and disease progression in patients with chronic liver disease.

PubMed

Irvine, Katharine M; Wockner, Leesa F; Shanker, Mihir; Fagan, Kevin J; Horsfall, Leigh U; Fletcher, Linda M; Ungerer, Jacobus P J; Pretorius, Carel J; Miller, Gregory C; Clouston, Andrew D; Lampe, Guy; Powell, Elizabeth E

2016-03-01

Current tools for risk stratification of chronic liver disease subjects are limited. We aimed to determine whether the serum-based ELF (Enhanced Liver Fibrosis) test predicted liver-related clinical outcomes, or progression to advanced liver disease, and to compare the performance of ELF to liver biopsy and non-invasive algorithms. Three hundred patients with ELF scores assayed at the time of liver biopsy were followed up (median 6.1 years) for liver-related clinical outcomes (n = 16) and clear evidence of progression to advanced fibrosis (n = 18), by review of medical records and clinical data. Fourteen of 73 (19.2%) patients with ELF score indicative of advanced fibrosis (≥9.8, the manufacturer's cut-off) had a liver-related clinical outcome, compared to only two of 227 (<1%) patients with ELF score <9.8. In contrast, the simple scores APRI and FIB-4 would only have predicted subsequent decompensation in six and four patients respectively. A unit increase in ELF score was associated with a 2.53-fold increased risk of a liver-related event (adjusted for age and stage of fibrosis). In patients without advanced fibrosis on biopsy at recruitment, 55% (10/18) with an ELF score ≥9.8 showed clear evidence of progression to advanced fibrosis (after an average 6 years), whereas only 3.5% of those with an ELF score <9.8 (8/207) progressed (average 14 years). In these subjects, a unit increase in ELF score was associated with a 4.34-fold increased risk of progression. The ELF score is a valuable tool for risk stratification of patients with chronic liver disease. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

On Alfvenic Waves and Stochastic Ion Heating with 1Re Observations of Strong Field-aligned Currents, Electric Fields, and O+ ions

NASA Technical Reports Server (NTRS)

Coffey, Victoria; Chandler, Michael; Singh, Nagendra

2008-01-01

The role that the cleft/cusp has in ionosphere/magnetosphere coupling makes it a very dynamic region having similar fundamental processes to those within the auroral regions. With Polar passing through the cusp at 1 Re in the Spring of 1996, we observe a strong correlation between ion heating and broadband ELF (BBELF) emissions. This commonly observed relationship led to the study of the coupling of large field-aligned currents, burst electric fields, and the thermal O+ ions. We demonstrate the role of these measurements to Alfvenic waves and stochastic ion heating. Finally we will show the properties of the resulting density cavities.

Pharmacodynamics of Levofloxacin in a Murine Pneumonia Model of Pseudomonas aeruginosa Infection: Determination of Epithelial Lining Fluid Targets▿

PubMed Central

Louie, Arnold; Fregeau, Christine; Liu, Weiguo; Kulawy, Robert; Drusano, G. L.

2009-01-01

The dose choice for Pseudomonas aeruginosa remains a matter of debate. The actual exposure targets required for multilog killing of organisms at the primary infection site have not been delineated. We studied Pseudomonas aeruginosa PAO1 using a murine model of pneumonia. We employed a large mathematical model to fit all the concentration-time data in plasma and epithelial lining fluid (ELF) as well as colony counts in lung simultaneously for all drug doses. Penetration into ELF was calculated to be approximately 77.7%, as indexed to the ratio of the area under the concentration-time curve for ELF (AUCELF) to the AUCplasma. We determined the ELF concentration-time profile required to drive a stasis response as well as 1-, 2-, or 3-log10(CFU/g) kill. AUC/MIC ratios of 12.4, 31.2, 62.8, and 127.6 were required to drive these bacterial responses. Emergence of resistance was seen only at the two lowest doses (three of five animals at 50 mg/kg [body weight] and one of five animals at 100 mg/kg). The low exposure targets were likely driven by a low mutational frequency to resistance. Bridging to humans was performed using Monte Carlo simulation. With a 750-mg levofloxacin dose, target attainment rates fell below 90% at 4 mg/liter, 1 mg/liter, and 0.5 mg/liter for 1-, 2-, and 3-log kills, respectively. Given the low exposure targets seen with this strain, we conclude that levofloxacin at a 750-mg dose is not adequate for serious Pseudomonas aeruginosa pneumonia as a single agent. More isolates need to be studied to make these observations more robust. PMID:19364849

Low-Latitude ELF Emissions Below 100Hz Observed in Taiwan

NASA Astrophysics Data System (ADS)

Wang, K.; Wang, Y.; Su, H.; Hsu, R.

2005-12-01

ELF antennas have been mounted at the Lulin Observatory (23.47oN, 120.87oE; 2862m) and National Cheng Kung University (23.00oN, 120.22oE, 32m) in Taiwan for study of global lightning activities and ELF events. We have previously reported 10-month ELF-Whistlers observations from Aug. 26, 2003 to July 13, 2004. [Wang et al., 2005]. In addition to these events, other forms of ELF emissions were also detected. In this study, an Atlas of these observed ELF emissions below 100Hz for the same period of observation is presented. Total numbers of more than 100 detected events are categorized into six groups: discrete emissions, periodic emissions, quasi-periodic emissions, hiss, chorus, and triggered emissions, according to the system of classification for VLF emissions in [Helliwell, 1965]. Nevertheless, there are still some emissions hardly to be classified. Diurnal and seasonal variations of occurrences for these ELF emission events are analyzed. Correlation between these events and storm indices will also be discussed. References Helliwell, R. A., VLF Emission, in Whistlers and Related Ionospheric Phenomena, Stanford University Press, Stanford, California, 1965. Wang . Y. C., K. Wang, H. T. Su, R. R. Hsu, Low-Latitude ELF-Whistlers observed in Taiwan, Geophys. Res. Lett., 32, L08102, doi:10.1029/2005GL022412, 20

Assessment of occupational exposure to extremely low frequency magnetic fields in hospital personnel.

PubMed

Úbeda, Alejandro; Martínez, María Antonia; Cid, María Antonia; Chacón, Lucía; Trillo, María A; Leal, Jocelyne

2011-07-01

It has been proposed that chronic exposure to extremely low frequency (ELF) magnetic fields (MF) in occupational environments could represent a risk factor for a number of disorders. Medical and technical workers in hospitals have been reported to be exposed to relatively strong ELF fields. The present work aims to characterize exposure to MF in the 5 Hz to 2 kHz frequency range in a large hospital through both instantaneous environmental measurements and personal monitoring of workers. The study was conducted in different working environments of a hospital with about 4400 employees, many of them working at two or more different work stations and consequently, exposed to MF levels that were expected to be unevenly distributed in space and time. The results indicate that: (1) The dominant frequency at the studied environments was 50 Hz (average 90.8 ± 6% of the total B value); (2) The best descriptive information on a worker's exposure is obtained from personal monitoring of volunteer workers; (3) The arithmetic averages of exposure levels obtained from the monitoring ranged from 0.03 ± 0.01 µT in nurses to 0.39 ± 0.13 µT in physiotherapists; and (4) The description of the MF environment through spot measurements in the workplace, although coherent with the data from personal monitoring, might not adequately estimate MF exposure in some professional categories. Copyright © 2011 Wiley-Liss, Inc.

E74-like factor 2 regulates valosin-containing protein expression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Binglin; Tomita, Yasuhiko; Qiu, Ying

2007-05-11

Enhanced expression of valosin-containing protein (VCP) correlates with invasion and metastasis of cancers. To clarify the transcription mechanism of VCP, human and mouse genomic sequence was compared, revealing a 260 bp DNA sequence in the 5'-flanking region of VCP gene to be highly conserved between the two, in which binding motif of E74-like factor 2/new Ets-related factor (ELF2/NERF) was identified. Chromatin immunoprecipitation assay showed binding of ELF2/NERF to the 5'-flanking region of VCP gene. Knock-down of ELF2/NERF by siRNA decreased expression level of VCP. Viability of cells under tumor necrosis factor-alpha treatment significantly reduced in ELF2/NERF-knock-down breast cancer cell line.more » Immunohistochemical analysis on clinical breast cancer specimens showed a correlation of nuclear ELF2/NERF expression with VCP expression and proliferative activity of cells shown by Ki-67 immunohistochemistry. These findings indicate that ELF2/NERF promotes VCP transcription and that ELF2/NERF-VCP pathway might be important for cell survival and proliferation under cytokine stress.« less

Identification of multiple nuclear localization signals in murine Elf3, an ETS transcription factor.

PubMed

Do, Hyun-Jin; Song, Hyuk; Yang, Heung-Mo; Kim, Dong-Ku; Kim, Nam-Hyung; Kim, Jin-Hoi; Cha, Kwang-Yul; Chung, Hyung-Min; Kim, Jae-Hwan

2006-03-20

We investigated nuclear localization signal (NLS) determinants within the AT-hook and ETS DNA-binding domains of murine Elf3 (mElf3), a member of the subfamily of epithelium-specific ETS transcription factors. Deletion mutants containing the AT-hook, ETS domain or both localized strictly in the nucleus, suggesting that these individual domains contain independent NLS motif(s). Within the AT-hook domain, four basic residues (244KRKR247) were critical for strong NLS activity, and two potent bipartite NLS motifs (236-252 and 249-267) were sufficient for nuclear import of mElf3, although less efficient than the full domain. In addition, one stretch of basic residues (318KKK320) within the ETS domain appears to be essential for mElf3 nuclear localization. Taken together, mElf3 contains multiple NLS motifs, which may function cooperatively to effect efficient nuclear transport.

When theory and observation collide: Can non-ionizing radiation cause cancer?

PubMed

Havas, Magda

2017-02-01

This paper attempts to resolve the debate about whether non-ionizing radiation (NIR) can cause cancer-a debate that has been ongoing for decades. The rationale, put forward mostly by physicists and accepted by many health agencies, is that, "since NIR does not have enough energy to dislodge electrons, it is unable to cause cancer." This argument is based on a flawed assumption and uses the model of ionizing radiation (IR) to explain NIR, which is inappropriate. Evidence of free-radical damage has been repeatedly documented among humans, animals, plants and microorganisms for both extremely low frequency (ELF) electromagnetic fields (EMF) and for radio frequency (RF) radiation, neither of which is ionizing. While IR directly damages DNA, NIR interferes with the oxidative repair mechanisms resulting in oxidative stress, damage to cellular components including DNA, and damage to cellular processes leading to cancer. Furthermore, free-radical damage explains the increased cancer risks associated with mobile phone use, occupational exposure to NIR (ELF EMF and RFR), and residential exposure to power lines and RF transmitters including mobile phones, cell phone base stations, broadcast antennas, and radar installations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bacterial growth rates are influenced by cellular characteristics of individual species when immersed in electromagnetic fields.

PubMed

Tessaro, Lucas W E; Murugan, Nirosha J; Persinger, Michael A

2015-03-01

Previous studies have shown that exposure to extremely low-frequency electromagnetic fields (ELF-EMFs) have negative effects on the rate of growth of bacteria. In the present study, two Gram-positive and two Gram-negative species were exposed to six magnetic field conditions in broth cultures. Three variations of the 'Thomas' pulsed frequency-modulated pattern; a strong-static "puck" magnet upwards of 5000G in intensity; a pair of these magnets rotating opposite one another at ∼30rpm; and finally a strong dynamic magnetic field generator termed the 'Resonator' with an average intensity of 250μT were used. Growth rate was discerned by optical density (OD) measurements every hour at 600nm. ELF-EMF conditions significantly affected the rates of growth of the bacterial cultures, while the two static magnetic field conditions were not statistically significant. Most interestingly, the 'Resonator' dynamic magnetic field increased the rates of growth of three species (Staphylococcus epidermidis, Staphylococcus aureus, and Escherichia coli), while slowing the growth of one (Serratia marcescens). We suggest that these effects are due to individual biophysical characteristics of the bacterial species. Copyright © 2015 Elsevier GmbH. All rights reserved.

Effects of Extremely Low Frequency Magnetic Field on Neurite Outgrowth of PC12 and PC12D Cells and Evaluation by Image Analysis

NASA Astrophysics Data System (ADS)

Sakanishi, Akio; Takatsuki, Hideyo; Yoshikoshi, Akio; Fujiwara, Yasuyoshi

2004-05-01

A pheochromocytoma cell (PC12), and its derivative (PC12D), differentiate to nervelike cells in culture with the nerve growth factor (NGF) and forskolin respectively. We introduced a morphological factor σ=L/2(π A)1/2 for quantitating neurite outgrowth under a microscope in the presence of extremely low-frequency (ELF) magnetic fields for 22 hours, where L and A are the contour length and the area of the cells in clump determined using an image-analysis system. ELF magnetic fields B1 were generated with a single coil or double coils in Helmholtz configuration together with static fields B0 of -53, -20 and 67 μT. σ increased with increasing NGF or forskolin level at B0=-53 μT (geomagnetism), in agreement with the cytometric observation of micrographs. With the addition of an AC field B1 at 60 Hz (100 μT > B1 > 3 μT rms) to B0, neurite outgrowth represented by σ was depressed for PC12 and stimulated for PC12D. We discuss the cyclotron resonance and the ion parametric resonance models.

Chemical exposure-response relationship between air pollutants and reactive oxygen species in the human respiratory tract

NASA Astrophysics Data System (ADS)

Lakey, P. S. J.; Berkemeier, T.; Tong, H.; Arangio, A. M.; Lucas, K.; Poeschl, U.; Shiraiwa, M.

2016-12-01

The inhalation of air pollutants such as O3 and particulate matter can lead to the formation of reactive oxygen species (ROS) which can cause damage to biosurfaces such as the lung epithelium unless they are effectively scavenged. Although the chemical processes that lead to ROS formation within the ELF upon inhalation of pollutants are well understood qualitatively, ROS concentrations within the ELF have hardly been quantified so far. The kinetic multi-layer model of surface and bulk chemistry in the epithelial lining fluid (KM-SUB-ELF) has been developed to describe chemical reactions and mass transport and to quantify ROS production rates and concentrations within the epithelial lining fluid. KM-SUB-ELF simulations suggest that O3 will rapidly saturate the ELF whereas antioxidants and surfactant species are effective scavengers of OH. High ambient concentrations of O3 can lead to the depletion of surfactants and antioxidants within the ELF, potentially leading to oxidative stress. KM-SUB-ELF reproduced measurements for the formation of H2O2 and OH due to the presence of iron, copper and quinones in surrogate lung lining fluid. This enabled ROS production rates and concentrations in the ELF to be quantified. We found that in polluted megacities the ROS concentration in the ELF due to inhalation of pollutants was at least as high as the concentrations in the ELF of patients suffering from respiratory diseases. Cu and Fe are found to be the most important redox-active aerosol components for ROS production upon inhalation of PM2.5 in polluted regions. Therefore, a reduction in the emission of Cu and Fe should be major targets of air pollution control. Chemical exposure-response relations provide a quantitative basis for assessing the relative importance of specific air pollutants in different regions of the world, showing that aerosol-induced epithelial ROS levels in polluted megacity air can be several orders of magnitude higher than in pristine rainforest air.

Supplemental Reactor Physics Calculations and Analysis of ELF Mk 1A Fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pope, Michael A.

2014-10-01

These calculations supplement previous the reactor physics work evaluating the Enhanced Low Enriched Uranium (LEU) Fuel (ELF) Mk 1A element. This includes various additional comparisons between the current Highly Enriched Uranium (HEU) and LEU along with further characterization of the performance of the ELF fuel. The excess reactivity to be held down at BOC for ELF Mk 1A fuel is estimated to be approximately $2.75 greater than with HEU for a typical cycle. This is a combined effect of the absence of burnable poison in the ELF fuel and the reduced neck shim worth in LEU fuel compared to HEU.more » Burnable poison rods were conceptualized for use in the small B positions containing Gd2O3 absorber. These were shown to provide $2.37 of negative reactivity at BOC and to burn out in less than half of a cycle. The worth of OSCCs is approximately the same between HEU and ELF Mk 1A (LEU) fuels in the representative loading evaluated. This was evaluated by rotating all banks simultaneously. The safety rod worth is relatively unchanged between HEU and ELF Mk 1A (LEU) fuels in the representative loading evaluated. However, this should be reevaluated with different loadings. Neutron flux, both total and fast (>1 MeV), is either the same or reduced upon changing from HEU to ELF Mk 1A (LEU) fuels in the representative loading evaluated. This is consistent with the well-established trend of lower neutron fluxes for a given power in LEU than HEU.The IPT loop void reactivity is approximately the same or less positive with ELF Mk 1A (LEU) fuel than HEU in the representative loading evaluated.« less

Extensive proteomic remodeling is induced by eukaryotic translation elongation factor 1Bγ deletion in Aspergillus fumigatus.

PubMed

O'Keeffe, Grainne; Jöchl, Christoph; Kavanagh, Kevin; Doyle, Sean

2013-11-01

The opportunistic pathogen Aspergillus fumigatus is ubiquitous in the environment and predominantly infects immunocompromised patients. The functions of many genes remain unknown despite sequencing of the fungal genome. A putative translation elongation factor 1Bγ (eEF1Bγ, termed elfA; 750 bp) is expressed, and exhibits glutathione S-transferase activity, in A. fumigatus. Here, we demonstrate the role of ElfA in the oxidative stress response, as well as a possible involvement in translation and actin cytoskeleton organization, respectively. Comparative proteomics, in addition to phenotypic analysis, under basal and oxidative stress conditions, demonstrated a role for A. fumigatus elfA in the oxidative stress response. An elfA-deficient strain (A. fumigatus ΔelfA) was significantly more sensitive to the oxidants H2O2, diamide, and 4,4'-dipyridyl disulfide (DPS) than the wild-type. This was further supported with the identification of differentially expressed proteins of the oxidative stress response, including; mitochondrial peroxiredoxin Prx1, molecular chaperone Hsp70 and mitochondrial glycerol-3-phosphate dehydrogenase. Phenotypic analysis also revealed that A. fumigatus ΔelfA was significantly more tolerant to voriconazole than the wild-type. The differential expression of two aminoacyl-tRNA synthetases suggests a role for A. fumigatus elfA in translation, while the identification of actin-bundling protein Sac6 and vacuolar dynamin-like GTPase VpsA link A. fumigatus elfA to the actin cytoskeleton. Overall, this work highlights the diverse roles of A. fumigatus elfA, with respect to translation, oxidative stress and actin cytoskeleton organization. In addition to this, the strategy of combining targeted gene deletion with comparative proteomics for elucidating the role of proteins of unknown function is further revealed. © 2013 The Protein Society.

Epigenetic restriction of embryonic cell lineage fate by methylation of Elf5

PubMed Central

Ng, Ray Kit; Dean, Wendy; Dawson, Claire; Lucifero, Diana; Madeja, Zofia; Reik, Wolf; Hemberger, Myriam

2008-01-01

Mouse ES cells can differentiate into all three germ layers of the embryo but are generally excluded from the trophoblast lineage. Here we show that ES cells deficient in DNA methylation can differentiate efficiently into trophoblast derivatives. In a genome-wide screen we identify the transcription factor Elf5 as methylated and repressed in ES cells, and hypomethylated and expressed in TS and methylation-deficient ES cells. Elf5 creates a positive feedback loop with TS cell determinants Cdx2 and Eomes that is restricted to the trophoblast lineage by epigenetic regulation of Elf5. Importantly, the late-acting function of Elf5 allows initial plasticity and regulation in the early blastocyst. Thus, Elf5 acts downstream of initial lineage determination as a gatekeeper to reinforce commitment to the trophoblast lineage, or to abort this pathway in epiblast cells. This epigenetic restriction of cell lineage fate provides a molecular mechanism for Waddington’s concept of canalization of developmental pathways. PMID:18836439

VLF Remote -Sensing of the Lower Ionosphere with AWESOME Receivers: Solar Flares, Lightning-induced Electron Precipitation, Sudden Ionospheric Disturbances, Sprites, Gravity Waves and Gamma-ray Flares

NASA Astrophysics Data System (ADS)

Inan, U. S.; Cohen, M.; Scherrer, P.; Scherrer, D.

2006-11-01

Stanford University Very Low Frequency (VLF) radio receivers have been used extensively for remote sensing of the ionosphere and the magnetosphere. Among the phenomena that can be uniquely measured via VLF receivers are radio atmospherics, whistlers, electron precipitation, solar flares, sudden ionospheric disturbances, gravity waves, sprites, and cosmic gamma-ray flares. With the use of simple square air-core magnetic loop antennas of a couple of meters in size, the sensitivity of these instruments allows the measurement of magnetic fields as low as several tens of femtoTesla per root Hz, in the frequency range of ~300 Hz to 50 kHz. This sensitivity well exceeds that required to detect any event above the ambient atmospheric noise floor, determined by the totality of lightning activity on this planet. In recent years, as cost of production, timing accuracy (due to low cost GPS cards), and data handling flexibility of the systems has improved, it has become possible to distribute many of these instruments in the form of arrays, to perform interferometric and holographic imaging of the lower ionosphere. These goals can be achieved using the newest version of the Stanford VLF receiver, known as AWESOME: Atmospheric Weather Educational System for Observation and Modeling of Electromagnetics. In the context of the IHY/UNBSS program for 2007, the AWESOME receivers can be used extensively as part of the United Nations initiative to place scientific instruments in developing countries. Drawing on the Stanford experiences from setting up arrays of VLF receivers, including an interferometer in Alaska, the Holographic Array for Ionospheric and Lightning research (HAIL) consisting of instruments at 13 different high schools in mid-western United States, a broader set of ELF/VLF receivers in Alaska, and various receivers abroad, including in France, Japan, Greece, Turkey, and India, a global network of ELF/VLF receivers offer possibilities for a wide range of scientific topics, as well as serving as a means for educational outreach. Most recently, AWESOME receivers were placed in several North African countries, including Tunisia, Algeria, and Morocco. The new AWESOME version is substantially lower in cost, and easier to set-up and use. Nevertheless, the receivers offer the same ultimate levels of resolution in time, sensitivity and dynamic range, as well as ease of handling of data that is used by researchers conducting cutting edge ionospheric and Space Weather research. In this context, the placement of these systems at underdeveloped host countries provides an open-ended potential for exploration, limited only by the imagination and drive of the users.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sugi, Yutaka; Takahashi, Kyoko, E-mail: ktaka@brs.nihon-u.ac.jp; Nakano, Kou

Highlights: {yields} Transcriptional activation of the Tollitip gene is higher in IECs than in monocytes. {yields} Nt -194/-186 region acts as a cis-element and is recognized by Elf-1. {yields} Elf-1 suppresses Tollip gene transcription in monocytes but not in IECs. {yields} O-GlcNAc modification is necessary for nuclear translocation of Elf-1. {yields} O-GlcNAcylation-dependent nuclear translocation of Elf-1 is impaired in IECs. -- Abstract: Intestinal epithelial cells (IECs) must be tolerant of the large number of commensal bacteria inhabiting the intestinal tract to avoid excessive inflammatory reactions. Toll-interacting protein (Tollip), a negative regulator of Toll-like receptor signaling, is known to be expressedmore » at high levels in IECs, and to thereby contribute to the hyporesponsiveness of IECs to commensals. In this study, we analyzed the underlying mechanisms for elevated transcription of the Tollip gene in IECs using a human IEC line, Caco-2, and a human monocyte line, THP-1, as a control. Elf-1 was identified as a transcription factor that negatively regulates Tollip gene expression. The transcription factor Elf-1 was localized in the nucleus by O-linked N-acetylglucosamine (O-GlcNAc) modification, whereas the unmodified form was detected only in the cytoplasm. Comparison of Caco-2 and THP-1 cells revealed that O-GlcNAc modification of Elf-1 was significantly lower in IECs than in monocytes. Collectively, the results indicate that insufficient O-GlcNAc modification prevents Elf-1-mediated transcriptional repression and thereby upregulates Tollip gene expression in IECs.« less

Coupling of ELF/ULF energy from lightning and MeV particles to the middle atmosphere, inosphere, and global circuit

NASA Technical Reports Server (NTRS)

Hale, Leslie C.

1994-01-01

In an attempt to explain numerous atmospheric electrical phenomena, the elements of the global electrical circuit are reexamined. In addition to being a 'quasi-static 'DC' generator' and source of radiated energy at VLF and higher, the thunderstorm is found to be a pulse generator, with most of the external energy contained in ELF and ULF pulse currents to the ionosphere (and Earth). The pulse energy is found to deposit largely in the middle atmosphere above the thunderstorm. The VLF and above components are well understood, as are the ULF components due to the conductivity gradient. However, a previously poorly understood ELF component on the millsecond timescale, or 'slow tail,' contains a large fraction of the electrical energy. This component couples strongly to the ionosphere and also launches a unipolar transverse electromagnetic (TEM) wavelet in the radial Earth-ionosphere transmission line. The increase in charge with distance associated with such wavelets, and their ensemble sum at a point, may explain some large mesospheric 'DC' fields but there are still difficulties explaining other than rare occurrences, except for antipodal reconvergence. These millisecond duration unipolar wavelets also coupled to the ionosphere and may trigger other lightning at a distance. A schema is elucidated by which the charge of MeV particles deposited in the middle atmosphere persists for much longer than the local relaxation time. This also gives rise to unipolar waves of global extent which may explain lower-latitude field perturbations associated with solar/geomagnetic events.

Active experiments in space; Proceedings of the Topical Meeting of the Interdisciplinary Scientific Commission D (Meeting D3) of the COSPAR 28th Plenary Meeting, The Hague, Netherlands, June 25-July 6, 1990

NASA Astrophysics Data System (ADS)

Torbert, R.

1992-12-01

The present volume on active experiments in space discusses dynamic trapping of electrons in the Porcupine ionospheric ion beam experiment, plasma wave observations during electron gun experiments on ISEE-1, spatial coherence and electromagnetic wave generation during electron beam experiments in space, and recent experimental measurements of space platform charging at LEO altitudes. Attention is given to high voltage spheres in an unmagnetized plasma, energetic ion emission for active spacecraft control, the collective gyration of a heavy ion cloud in a magnetized plasma, and remote sensing of artificial luminous clouds by lidars. Topics addressed include modulation of the background flux of energetic particles by artificial injection, wave measurements in active experiments on plasma beam injection, field formation around negatively biased solar arrays in the LEO-plasma, and the registration of ELF waves in rocket-satellite experiments with plasma injection.

Generation and propagation of electromagnetic waves in the magnetosphere. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Taylor, W. W. L.

1973-01-01

Characteristics of broadband ELF, VLF, and LF emissions in the magnetosphere were calculated assuming incoherent Cerenkov radiation from magnetospheric electrons with energies from 50 eV to 50 keV. Calculations were included to determine the ray paths of the emitted waves. A diffusive equilibrium model of the magnetosphere with an ionosphere, plasmapause, and a centered dipole magnetic field was used. Ray path calculations were done in three dimensions. Using simultaneous energetic electron and VLF data, comparisons were made between calculated and observed VLF hiss. Assuming a wave normal angle six degrees from the resonance cone angle, the calculated spectral densities are both two orders of magnitude below the observed spectral densities. It seems unlikely that VLF hiss is produced by incoherent Cerenkov radiation. The observed spectral shape of V-shaped VLF hiss is similar to that calculated from incoherent Cerenkov radiation.

Initial survey of the wave distribution functions for plasmaspheric hiss observed by ISEE 1

NASA Technical Reports Server (NTRS)

Storey, L. R. O.; Lefeuvre, F.; Parrot, M.; Cairo, L.; Anderson, R. R.

1991-01-01

The generation mechanism of hiss observed by ISEE 1 satellite in the earth magnetosphere is investigated by analyzing the ELF/VLF wave data obtained from four passes of ISEE 1, all of which occurring during magnetically quiet periods. The results of these measurements, together with those published earlier, indicate that the generation mechanisms proposed by Kennel alnd Petschek (1966), by Thorne et al. (1979), and by Solomon et al. (1988, 1989) are all physically possible and can come into action whenever the necessary conditions exist. However, plasmaspheric hiss was observed by ISEE even when the conditions for any of these mechanisms existed; under these conditions, hiss appears to be generated near the equatorial plane over a wide range of L values, with the wave normals at large angles to the field. The generation mechanism that applies in such cases is still unknown.

LEP Events, TLE's, and Q-bursts observed from the Antarctic

NASA Astrophysics Data System (ADS)

Moore, R. C.; Kim, D.; Flint, Q. A.

2017-12-01

ELF/VLF measurements at Palmer Station, McMurdo Station, and South Pole Station, Antarctica are used to detect lightning-generated ELF/VLF radio atmospherics from around the globe and to remote sense ionospheric disturbances in the Southern hemisphere. The Antarctic ELF/VLF receivers complement a Northern hemisphere ELF/VLF monitoring array. In this paper, we present our latest observational results, including a full statistical analysis of conjugate observations of lightning-induced electron precipitation and radio atmospherics associated specifically with the transient luminous events known as gigantic jets and sprites.

Protein Kinase Cι Drives a NOTCH3-dependent Stem-like Phenotype in Mutant KRAS Lung Adenocarcinoma.

PubMed

Ali, Syed A; Justilien, Verline; Jamieson, Lee; Murray, Nicole R; Fields, Alan P

2016-03-14

We report that the protein kinase Cι (PKCι) oncogene controls expression of NOTCH3, a key driver of stemness, in KRAS-mediated lung adenocarcinoma (LADC). PKCι activates NOTCH3 expression by phosphorylating the ELF3 transcription factor and driving ELF3 occupancy on the NOTCH3 promoter. PKCι-ELF3-NOTCH3 signaling controls the tumor-initiating cell phenotype by regulating asymmetric cell division, a process necessary for tumor initiation and maintenance. Primary LADC tumors exhibit PKCι-ELF3-NOTCH3 signaling, and combined pharmacologic blockade of PKCι and NOTCH synergistically inhibits tumorigenic behavior in vitro and LADC growth in vivo demonstrating the therapeutic potential of PKCι-ELF3-NOTCH3 signal inhibition to more effectively treat KRAS LADC. Copyright © 2016 Elsevier Inc. All rights reserved.

Processing LiDAR Data to Predict Natural Hazards

NASA Technical Reports Server (NTRS)

Fairweather, Ian; Crabtree, Robert; Hager, Stacey

2008-01-01

ELF-Base and ELF-Hazards (wherein 'ELF' signifies 'Extract LiDAR Features' and 'LiDAR' signifies 'light detection and ranging') are developmental software modules for processing remote-sensing LiDAR data to identify past natural hazards (principally, landslides) and predict future ones. ELF-Base processes raw LiDAR data, including LiDAR intensity data that are often ignored in other software, to create digital terrain models (DTMs) and digital feature models (DFMs) with sub-meter accuracy. ELF-Hazards fuses raw LiDAR data, data from multispectral and hyperspectral optical images, and DTMs and DFMs generated by ELF-Base to generate hazard risk maps. Advanced algorithms in these software modules include line-enhancement and edge-detection algorithms, surface-characterization algorithms, and algorithms that implement innovative data-fusion techniques. The line-extraction and edge-detection algorithms enable users to locate such features as faults and landslide headwall scarps. Also implemented in this software are improved methodologies for identification and mapping of past landslide events by use of (1) accurate, ELF-derived surface characterizations and (2) three LiDAR/optical-data-fusion techniques: post-classification data fusion, maximum-likelihood estimation modeling, and hierarchical within-class discrimination. This software is expected to enable faster, more accurate forecasting of natural hazards than has previously been possible.

VLF emissions in the Venus foreshock - Comparison with terrestrial observations

NASA Technical Reports Server (NTRS)

Crawford, G. K.; Strangeway, R. J.; Russell, C. T.

1993-01-01

An examination is conducted of ELF/VLF emissions observed in the solar wind upstream of the Venus shock, for the 100 Hz-30 kHz range, using data from the Pioneer Venus Orbiter's electric field detector and magnetometer instruments. Detailed comparisons are made with terrestrial measurements for both the electron and ion foreshocks. The results obtained support the Crawford et al. (1990) identification of the Venus electron foreshock emissions as electron plasma oscillations, whose waves are generated in situ and act to isotropize the electron distributions.

Compilation of 1982 Annual Reports of the Navy ELF (Extremely Low Frequency) Communications System Ecological Monitoring Program.

DTIC Science & Technology

1983-05-01

systems are generally considered difficult to study, several features of ectomycor- rhizae facilitate such investigations. Ectomycorrhizal fungi...communications antenna area and 2) distribution features of the induced field in the forest floor. The overall objective of these studies is to quantify key...Sultanova, K. Kayumov, and 0. Khasahov. 1981. Some features of microbiological processes under alfalfa depending on hoeing depth and fertilizer

Extremely Low Frequency (ELF) Communications System Ecological Monitoring Program: Summary of 1983 Progress.

DTIC Science & Technology

1984-07-01

gather quantita- tive data on the flowering periods of various entomophilous plants at the study sites. Once the pollen relationships of the various bee...during 1983. For all hardwood species on study plots (i.e., test and control), bud burst, leaf out, full foliage, flowering , cambial activity, seed...value to megachilids e qualitative and quantitative determination of pertinent flowering phenologies o development of qualitative and quantitative

Extremely Low Frequency (ELF) Communications System Ecological Monitoring Program: Summary of 1986 Progress.

DTIC Science & Technology

1987-12-01

assessment of data collection techniques *quantification of temporal and spatial patterns of variables *assessment of end point variability...nutrient variables are also being examined as covarlates. Development of a model to test for differences in growth patterns is continuing. At each of...condition. These variables are recorded at the end of each growing season. For evaluation of height growth patterns , a subsample of 100 seedlings per

Utility of the ELF Test for Detecting Steatohepatitis in Morbid Obese Patients with Suspicion of Nonalcoholic Fatty Liver Disease.

PubMed

López, Iria Cebreiros; Aroca, Florentina Guzmán; Bernal, Maria Dolores Frutos; Mompeán, Juan Antonio Luján; Bernal, Águeda Bas; Martínez, Antonio Miguel Hernández; Barba, Enrique Martínez; Velasco, Jose Antonio Noguera; Paricio, Pascual Parilla

2017-09-01

Morbid obese patients have a high rate of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). NASH is related to the progression and poor evolution of chronic hepatopathy in NAFLD, so that its detection makes it possible to identify the subjects who are most at risk in order to prioritize treatment. The ELF test (Enhanced Liver Fibrosis test; Siemens Diagnostics, NY, USA) has been assessed for its capacity to detect fibrosis in patients with NAFLD, but its capacity for diagnosing NASH has not been checked. Our objective is to determine the utility of the ELF test for detecting NASH in morbid obese patients with suspected NAFLD. ELF values were determined in a cohort of obese patients who underwent bariatric surgery with suspected NAFLD. Liver biopsy was used as the reference standard. The values of ELF were significantly higher in patients with NASH (p = 0.002) and in those who presented with metabolic syndrome (p = 0.047). An ELF cut-off point of 8.72 allows the detection of patients with NASH with a sensitivity of 71.4% and a specificity of 74.1% (AUC = 0.742, p = 0.002). The ELF test is efficient for the identification of obese patients with NAFLD and early signs of steatohepatitis and fibrosis.

Comparing performances of logistic regression and neural networks for predicting melatonin excretion patterns in the rat exposed to ELF magnetic fields.

PubMed

Jahandideh, Samad; Abdolmaleki, Parviz; Movahedi, Mohammad Mehdi

2010-02-01

Various studies have been reported on the bioeffects of magnetic field exposure; however, no consensus or guideline is available for experimental designs relating to exposure conditions as yet. In this study, logistic regression (LR) and artificial neural networks (ANNs) were used in order to analyze and predict the melatonin excretion patterns in the rat exposed to extremely low frequency magnetic fields (ELF-MF). Subsequently, on a database containing 33 experiments, performances of LR and ANNs were compared through resubstitution and jackknife tests. Predictor variables were more effective parameters and included frequency, polarization, exposure duration, and strength of magnetic fields. Also, five performance measures including accuracy, sensitivity, specificity, Matthew's Correlation Coefficient (MCC) and normalized percentage, better than random (S) were used to evaluate the performance of models. The LR as a conventional model obtained poor prediction performance. Nonetheless, LR distinguished the duration of magnetic fields as a statistically significant parameter. Also, horizontal polarization of magnetic fields with the highest logit coefficient (or parameter estimate) with negative sign was found to be the strongest indicator for experimental designs relating to exposure conditions. This means that each experiment with horizontal polarization of magnetic fields has a higher probability to result in "not changed melatonin level" pattern. On the other hand, ANNs, a more powerful model which has not been introduced in predicting melatonin excretion patterns in the rat exposed to ELF-MF, showed high performance measure values and higher reliability, especially obtaining 0.55 value of MCC through jackknife tests. Obtained results showed that such predictor models are promising and may play a useful role in defining guidelines for experimental designs relating to exposure conditions. In conclusion, analysis of the bioelectromagnetic data could result in finding a relationship between electromagnetic fields and different biological processes. (c) 2009 Wiley-Liss, Inc.

Biological effects from electromagnetic field exposure and public exposure standards.

PubMed

Hardell, Lennart; Sage, Cindy

2008-02-01

During recent years there has been increasing public concern on potential health risks from power-frequency fields (extremely low frequency electromagnetic fields; ELF) and from radiofrequency/microwave radiation emissions (RF) from wireless communications. Non-thermal (low-intensity) biological effects have not been considered for regulation of microwave exposure, although numerous scientific reports indicate such effects. The BioInitiative Report is based on an international research and public policy initiative to give an overview of what is known of biological effects that occur at low-intensity electromagnetic fields (EMFs) exposure. Health endpoints reported to be associated with ELF and/or RF include childhood leukaemia, brain tumours, genotoxic effects, neurological effects and neurodegenerative diseases, immune system deregulation, allergic and inflammatory responses, breast cancer, miscarriage and some cardiovascular effects. The BioInitiative Report concluded that a reasonable suspicion of risk exists based on clear evidence of bioeffects at environmentally relevant levels, which, with prolonged exposures may reasonably be presumed to result in health impacts. Regarding ELF a new lower public safety limit for habitable space adjacent to all new or upgraded power lines and for all other new constructions should be applied. A new lower limit should also be used for existing habitable space for children and/or women who are pregnant. A precautionary limit should be adopted for outdoor, cumulative RF exposure and for cumulative indoor RF fields with considerably lower limits than existing guidelines, see the BioInitiative Report. The current guidelines for the US and European microwave exposure from mobile phones, for the brain are 1.6 W/Kg and 2 W/Kg, respectively. Since use of mobile phones is associated with an increased risk for brain tumour after 10 years, a new biologically based guideline is warranted. Other health impacts associated with exposure to electromagnetic fields not summarized here may be found in the BioInitiative Report at www.bioinitiative.org.

Successful ELF Communications and Implications for ELT: Sequential Analysis of ELF Pronunciation Negotiation Strategies

ERIC Educational Resources Information Center

Matsumoto, Yumi

2011-01-01

This is a qualitative study of nonnative English speakers who speak English as a lingua franca (ELF) in their graduate student dormitory in the United States, a community of practice (Wegner, 2004) comprised almost entirely of second language users. Using a sequential analysis (Koshik, 2002; Markee, 2000; Sacks, Schegloff, & Jefferson, 1974;…

Expressing Disagreement in ELF Business Negotiations: Theory and Practice

ERIC Educational Resources Information Center

Bjorge, Anne Kari

2012-01-01

English spoken by those who do not share their first language is increasingly referred to as English lingua franca (ELF). For ELF speakers, it can be a challenge to express conflicting opinions, as a common language and/or cultural background cannot be taken for granted. This is recognized by writers of business English textbooks, who provide…

Reaction of physiological factors on the solar-geomagnetic activity (the physical mechanisms)

NASA Astrophysics Data System (ADS)

Avakyan, Sergey; Voronin, Nikolai; Dubarenko, Konstantin

This presentation proposes and provides substantiation for a hypothesis concerning the mechanism by which solar and geomagnetic activity (mainly of solar flares and magnetic storms) affects the biosphere, including man. The hypothesis, including a physical mechanism introduced by the authors, is that high-lying (Rydberg) states of all gases of the earth’s upper atmosphere are excited by ionospheric energetic electrons. Rydberg atoms, molecules and ions of all atmospheric gases emit characteristic radio emission in the spectral range from decimeters to millimeters. This radiation can easily penetrate to low atmosphere and biosphere carrying complete information about power and duration of solar flare and geomagnetic storms to biosphere. The microwave radioemission have the resonances at the spectral range 109 ÷ 1012 Hz at the cells and membranes, DNA and RNA, molecules of haemoglobin, erythrocytes, and this fact can explain the extremely small threshold for influence of ionospheric radioemission at the monochromatic (characteristic) transitions on biological objects, including the viscosity of blood. The energy estimates of the flux intensity of microwave radiation of the ionosphere from Rydberg states are used to prove for the first time that the values of this flux agree with the experimental data. A method is proposed for distinguishing the contributions of microwave radiation and magnetic perturbation in the geo-biocorrelations, taking into account the effect that the magnetic-field variations are not in phase with the flux of corpuscles from the radiation belts in the ionosphere during the period of a geomagnetic storm. Quanta of microwave radiation are emitted from the heights of 90 - 360 km, i.e. in the basic ionosphere regions. Their energy by almost 10 orders of magnitude exceeds that of the quanta of low-frequency electromagnetic background of the ionosphere (with the frequencies lower than 100 Hz, which coincide with those of biorhythms). Thereby, combined consideration of geo-electromagnetic radiation with carrier microwave frequency whose amplitude is modulated with the low-frequency (informational) component, is very promising. Indeed, in the Earth ionosphere the Schumann resonator is located between the Earth’s surface and the ionosphere region at the heights of 100 to 150 km (under E-layer), while the Alfven resonator is substantially larger and occupies the entire F-region of the ionosphere, up to its upper part at the heights roughly 1000 km above the surface. Since virtually all characteristics of the ionosphere medium are specified by solar activity (and also by geomagnetic activity - at high latitudes, and even, in the case of the principal magnetic storms, at middle latitudes), the parameters of both resonators, in particular, such as the functional frequencies and Q-factor, reflect the current level of the activities, including their most powerful manifestations in cosmic weather perturbations: solar flares and geomagnetic storms. The experimental data related to helio-geo-biocorrelations indicate that the impact of solar flares, and, which is more important, of magnetic storms on patients with cardiovascular and cerebral circulation pathology is based on the increase of the blood viscosity under the influence of the amplified microwave radiation of the ionosphere, immunodisfunction develops due to deterioration of the quality of leukocytes under the same conditions as above, and the excitatory system is affected with microwave resonance at the frequencies of VLF - ELF amplitude modulation in Schumann (at frequencies above 7 Hz) and Alfven (at frequencies below 6 Hz and down to minor fractions of a Hertz) bands, which are close to basic rhythms of human brain. Indeed, these resonators display a set of basic frequencies: 6 - 7 to 40 Hz (Schumann’s) and 0,1 to 6 Hz (Alfven’s). In the first case, the resonance frequencies (roughly equal to 7.7, 13.8, 19.7, and 26.7 Hz) are consistent with Alpha, Beta, and Gamma waves in the human brain, while in the second resonator, the frequencies overlap both the interval of cardiovascular rhythms of the human body and the Delta and Theta rhythms of the brain. Note, however, that the energetics of these links is small, compared with the mechanism suggested by us, based on the carrier wave of the ionosphere microwave radiation: the energy of ELF quanta is by the factor of 108 - 1012 lower than of those in microwaves.

ELF exposure from mobile and cordless phones for the epidemiological MOBI-Kids study.

PubMed

Calderón, Carolina; Ichikawa, Hiroki; Taki, Masao; Wake, Kanako; Addison, Darren; Mee, Terry; Maslanyj, Myron; Kromhout, Hans; Lee, Ae-Kyoung; Sim, Malcolm R; Wiart, Joe; Cardis, Elisabeth

2017-04-01

This paper describes measurements and computational modelling carried out in the MOBI-Kids case-control study to assess the extremely low frequency (ELF) exposure of the brain from use of mobile and cordless phones. Four different communication systems were investigated: Global System for Mobile (GSM), Universal Mobile Telecommunications System (UMTS), Digital Enhanced Cordless Telecommunications (DECT) and Wi-Fi Voice over Internet Protocol (VoIP). The magnetic fields produced by the phones during transmission were measured under controlled laboratory conditions, and an equivalent loop was fitted to the data to produce three-dimensional extrapolations of the field. Computational modelling was then used to calculate the induced current density and electric field strength in the brain resulting from exposure to these magnetic fields. Human voxel phantoms of four different ages were used: 8, 11, 14 and adult. The results indicate that the current densities induced in the brain during DECT calls are likely to be an order of magnitude lower than those generated during GSM calls but over twice that during UMTS calls. The average current density during Wi-Fi VoIP calls was found to be lower than for UMTS by 30%, but the variability across the samples investigated was high. Spectral contributions were important to consider in relation to current density, particularly for DECT phones. This study suggests that the spatial distribution of the ELF induced current densities in brain tissues is determined by the physical characteristics of the phone (in particular battery position) while the amplitude is mainly dependent on communication system, thus providing a feasible basis for assessing ELF exposure in the epidemiological study. The number of phantoms was not large enough to provide definitive evidence of an increase of induced current density with age, but the data that are available suggest that, if present, the effect is likely to be very small. Copyright © 2017 Elsevier Ltd. All rights reserved.

Detection of endogenous alkaline phosphatase activity in intact cells by flow cytometry using the fluorogenic ELF-97 phosphatase substrate

NASA Technical Reports Server (NTRS)

Telford, W. G.; Cox, W. G.; Stiner, D.; Singer, V. L.; Doty, S. B.

1999-01-01

BACKGROUND: The alkaline phosphatase (AP) substrate 2-(5'-chloro-2'-phosphoryloxyphenyl)-6-chloro-4-(3H)-quinazolinone (ELF((R))-97 for enzyme-labeled fluorescence) has been found useful for the histochemical detection of endogenous AP activity and AP-tagged proteins and oligonucleotide probes. In this study, we evaluated its effectiveness at detecting endogenous AP activity by flow cytometry. METHODS: The ELF-97 phosphatase substrate was used to detect endogenous AP activity in UMR-106 rat osteosarcoma cells and primary cultures of chick chondrocytes. Cells were labeled with the ELF-97 reagent and analyzed by flow cytometry using an argon ultraviolet (UV) laser. For comparison purposes, cells were also assayed for AP using a Fast Red Violet LB azo dye assay previously described for use in detecting AP activity by flow cytometry. RESULTS: The ELF-97 phosphatase substrate effectively detected endogenous AP activity in UMR-106 cells, with over 95% of the resulting fluorescent signal resulting from AP-specific activity (as determined by levamisole inhibition of AP activity). In contrast, less than 70% of the fluorescent signal from the Fast Red Violet LB (FRV) assay was AP-dependent, reflecting the high intrinsic fluorescence of the unreacted components. The ELF-97 phosphatase assay was also able to detect very low AP activity in chick chondrocytes that was undetectable by the azo dye method. CONCLUSIONS: The ELF-97 phosphatase assay was able to detect endogenous AP activity in fixed mammalian and avian cells by flow cytometry with superior sensitivity to previously described assays. This work also shows the applicability of ELF-97 to flow cytometry, supplementing its previously demonstrated histochemical applications. Copyright 1999 Wiley-Liss, Inc.

Atmosphere-Ionosphere Electrodynamic Coupling

NASA Astrophysics Data System (ADS)

Sorokin, V. M.; Chmyrev, V. M.

Numerous phenomena that occur in the mesosphere, ionosphere, and the magnetosphere of the Earth are caused by the sources located in the lower atmosphere and on the ground. We describe the effects produced by lightning activity and by ground-based transmitters operated in high frequency (HF) and very low frequency (VLF) ranges. Among these phenomena are the ionosphere heating and the formation of plasma density inhomogeneities, the excitation of gamma ray bursts and atmospheric emissions in different spectral bands, the generation of ULF/ELF/VLF electromagnetic waves and plasma turbulence in the ionosphere, the stimulation of radiation belt electron precipitations and the acceleration of ions in the upper ionosphere. The most interesting results of experimental and theoretical studies of these phenomena are discussed below. The ionosphere is subject to the action of the conductive electric current flowing in the atmosphere-ionosphere circuit. We present a physical model of DC electric field and current formation in this circuit. The key element of this model is an external current, which is formed with the occurrence of convective upward transport of charged aerosols and their gravitational sedimentation in the atmosphere. An increase in the level of atmospheric radioactivity results in the appearance of additional ionization and change of electrical conductivity. Variation of conductivity and external current in the lower atmosphere leads to perturbation of the electric current flowing in the global atmosphere-ionosphere circuit and to the associated DC electric field perturbation both on the Earth's surface and in the ionosphere. Description of these processes and some results of the electric field and current calculations are presented below. The seismic-induced electric field perturbations produce noticeable effects in the ionosphere by generating the electromagnetic field and plasma disturbances. We describe the generation mechanisms of such experimentally observed effects as excitation of plasma density inhomogeneities, field-aligned currents, and ULF/ELF emissions and the modification of electron and ion altitude profiles in the upper ionosphere. The electrodynamic model of the ionosphere modification under the influence of some natural and man-made processes in the atmosphere is also discussed. The model is based on the satellite and ground measurements of electromagnetic field and plasma perturbations and on the data on atmospheric radioactivity and soil gas injection into the atmosphere.

Electric field studies: TLE-induced waveforms and ground conductivity impact on electric field propagation

NASA Astrophysics Data System (ADS)

Farges, Thomas; Garcia, Geraldine; Blanc, Elisabeth

2010-05-01

We review in this paper main results obtained from electric field (from VLF to HF) measurement campaigns realized by CEA in the framework of the Eurosprite program [Neubert et al., 2005, 2008] from 2003 to 2009 in France in different configurations. Two main topics have been studied: sprite or elve induced phenomena (radiation or perturbation) and wave propagation. Using a network of 4 stations, VLF radiations from sprite have been successfully located at 10 km from the sprite parent lightning, in agreement with possible sprite location, generally displaced from the parent lightning. The MF (300 kHz - 3 MHz) source bursts were identified simultaneously with the occurrence of sprites observed with cameras [Farges et al., 2004; Neubert et al., 2008]. These observations are compared to recent broadband measurements, assumed to be due to relativistic electron beam radiation related to sprites [Fullekrug et al., 2009]. Recently, in 2009, with a new instrumentation, an ELF tail has been clearly measured after the lightning waveform, while sprites were observed at about 500 km from our station. This ELF tail is usually observed at distances higher than thousand km and is associated to sprite generation. This opens the capacity to measure the charge moment of the parent-lightning, using such measurement close to the source. Farges et al. [2007] showed that just after a lightning return stroke, a strong transient attenuation is very frequently observed in the MF waves of radio transmissions. They showed that this perturbation is due to heating of the lower ionosphere by the lightning-induced EMP during few milliseconds. These perturbations are then the MF radio signature of the lightning EMP effects on the lower ionosphere, in the same way as elves correspond to their optical signature. The experiment also provided the electric field waveforms directly associated to elves, while lightning were not detected by Météorage. Many of them present a double peak feature. The propagation of the electromagnetic waves generated by lightning has also been studied in the frequency range 1 kHz-1MHz at distances lower than 1000 km from the lightning source. A propagation model has been developed to determine the ground waves which propagate in a homogenous medium using the analytical expression given by Maclean and Wu [1993]. This approach takes into account the electric finite conductivity and the fact that the Earth is spherical, which allow us to deal with over-the-horizon propagation. We installed in 2008 four stations which were more or less aligned - the maximum distance between two stations was about 870 km. Two stations were located close to the Mediterranean Sea and the two others inside the continent, at the centre of France. This station distribution and the observation period (from August to December) allowed statistical and physical studies, such as the influence of the electric conductivity on wave propagation. Comparison of electric field spectra, measured after propagation only over sea and only over ground, showed clearly the effects of ground conductivity on propagation. Comparison between observations and modelling has been used to evaluate the ground conductivity. In the future we will implement the sky-wave inside our model and validate it with the database.

Power line emission 50/60 Hz and Schumann resonances observed by microsatellite Chibis-M in the Earth's ionosphere

NASA Astrophysics Data System (ADS)

Dudkin, Denys; Pilipenko, Vyacheslav; Dudkin, Fedir; Pronenko, Vira; Klimov, Stanislav

2015-04-01

The overhead power lines are the sources of intense wideband electromagnetic (EM) emission, especially in ELF-VLF range, because of significant length (up to a few thousand kilometers) and strong 50/60 Hz currents with noticeable distortion. The radiation efficiency of the power line emission (PLE) increases with the harmonic order, so they are well observed by ground-based EM sensors. However their observations by low orbiting satellites (LEO) are very rare, particularly at basic harmonic 50/60 Hz, because of the ionospheric plasma opacity in ELF band. The Schumann resonance (SR) is the narrow-band EM noise that occurs due to the global thunderstorm activity in the Earth-ionosphere cavity. The first five eigenmodes of the SR are 7.8, 14.3, 20.8, 27.3 and 33.8 Hz and, thus, SR harmonics are also strongly absorbed by the Earth ionosphere. The published numerical simulations show that the penetration depth of such an ELF emission into the Earth's ionosphere is limited to 50-70 km for electric field and 120-240 km for magnetic field. From this follows, that PLE and SR can hardly ever be detected by LEO satellites, i.e. above the F-layer of ionosphere. In spite of this fact, these emissions were recently observed with use of the electric field antennas placed on the satellites C/NOFS (USA) and Chibis-M (Russia). Microsatellite Chibis-M was launched on January 24, 2012, at 23:18:30 UTC from the cargo ship "Progress M-13M" to circular orbit with altitude ~500 km and inclination ~52° . Chibis-M mass is about 40 kg where one third is a scientific instrumentation. The dimensions of the microsatellite case are 0.26x0.26x0.54 m with the outside mounted solar panels, service and scientific instrumentation. The main scientific objective of Chibis-M is the theoretical model verification for the atmospheric gamma-ray bursts. It requires the study of the accompanying EM processes such as the plasma waves produced by the lightning discharges in the VLF band. Chibis-M decayed on 15 October 2014. The Chibis-M electric sensor has a small 0.42 m tip-to-tip base and was developed in Lviv Centre of Institute for Space Research, Ukraine. The sensor provides the measurement of one electric field component, which is perpendicular to the orbital plane, in the frequency range of 0.1-40,000 Hz with the noise spectral density 0.8-0.04 (μV/m)/Hz0.5 (in the band 1-100 Hz the noise is 0.2-0.04 (μV/m)/Hz0.5). We present the space distribution of the observed PLE and SR harmonics in the latitude range ±52o and connection of the PLE sources with the high-voltage overhead power lines. The electric field data have been analyzed for all Chibis-M operating time (~ 2.5 years). The fact of PLE and SR detection by LEO satellites C/NOFS and Chibis-M suggests that the model of the transionospheric ELF EM field propagation should be refined.

Meteor fireball sounds identified

NASA Technical Reports Server (NTRS)

Keay, Colin

1992-01-01

Sounds heard simultaneously with the flight of large meteor fireballs are electrical in origin. Confirmation that Extra/Very Low Frequency (ELF/VLF) electromagnetic radiation is produced by the fireball was obtained by Japanese researchers. Although the generation mechanism is not fully understood, studies of the Meteorite Observation and Recovery Project (MORP) and other fireball data indicate that interaction with the atmosphere is definitely responsible and the cut-off magnitude of -9 found for sustained electrophonic sounds is supported by theory. Brief bursts of ELF/VLF radiation may accompany flares or explosions of smaller fireballs, producing transient sounds near favorably placed observers. Laboratory studies show that mundane physical objects can respond to electrical excitation and produce audible sounds. Reports of electrophonic sounds should no longer be discarded. A catalog of over 300 reports relating to electrophonic phenomena associated with meteor fireballs, aurorae, and lightning was assembled. Many other reports have been cataloged in Russian. These may assist the full solution of the similar long-standing and contentious mystery of audible auroral displays.

Artificial blood-flow controlling effects of inhomogeneity of twisted magnetic fields

NASA Astrophysics Data System (ADS)

Nakagawa, Hidenori; Ohuchi, Mikio

2017-06-01

We developed a blood-flow controlling system using magnetic therapy for some types of nervous diseases. In our research, we utilized overlapped extremely low frequency (ELF) fields for the most effective blood-flow for the system. Results showed the possibility that the inhomogeneous region obtained by overlapping the fields at 50 Hz, namely, a desirably twisted field revealed a significant difference in induced electromotive forces at the insertion points of electrodes. In addition, ELF exposures with a high inhomogeneity of the twisted field at 50 Hz out of phase were more effective in generating an induced electromotive difference by approximately 31%, as contrasted with the difference generated by the exposure in phase. We expect that the increase of the inhomogeneity of the twisted field around a blood vessel can produce the most effective electromotive difference in the blood, and also moderately affect the excitable cells relating to the autonomic nervous system for an outstanding blood-flow control in vivo.

ELF-VLF communications through the Earth Project report for calendar year 1984, revision 1

NASA Astrophysics Data System (ADS)

Buettner, H. M.; Burker, G. J.; Didwall, E. M.; Holladay, G.; Lytle, R. J.

1985-08-01

We use computer models and experiments to explore the feasibility of communication between points underground and on the Earth's surface. Emphasis is placed on ELF-VLF electromagnetic propagation through the Earth; nominally, we investigated propagation in the 200 Hz-30 kHz frequency range. The computer modeling included calculations of the fields of a point electric or magnetic source in a homogeneous half space or a stratified earth. Initial results for an insulated antenna of finite length are also considered. The experiments involved through-the-Earth transmissions at two locations in Pennsylvania, both of which had large formations of limestone. Initial results indicate that information rates as high as kbits/s may be possible for subsurface depths of 300 m or less. Accuracy of these estimates depends on the electromagnetic propagation constant of the rock, the noise characteristics, and the modulation scheme. Although a nuisance for evaluating through-the-Earth propagation, the existence of subsurface metal conductors can improve the transmission character of the site.

ELF-VLF communications through-the-Earth

NASA Astrophysics Data System (ADS)

Buettner, H. M.; Burke, G. J.; Didwall, E. M.; Holladay, G.; Lytle, R. J.

1985-06-01

We use computer models and experiments to explore the feasibility of communication between points underground and on the Earth's surface. Emphasis is placed on ELF-VLF electromagnetic propagation through the Earth; nominally, we investigated propagation in the 200 Hz-30 kHz frequency range. The computer modeling included calculations of the fields of a point electric or magnetic source in a homogeneous half space or a stratified Earth. Initial results for an insulated antenna of finite length are also considered. The experiments involved through-the-Earth transmissions at two locations in Pennsylvania, both of which had large formations of limestone. Initial results indicate that information rates as high as kbits/s may be possible for subsurface depths of 300 m or less. Accuracy of these estimates depends on the electromagnetic propagation constants of the rock, the noise characteristics, and modulation scheme. Although a nuisance for evaluating through-the-Earth propagation, the existence of subsurface metal conductors can improve the transmission character of the site.

Peculiar transient events in the Schumann resonance band and their possible explanation

NASA Astrophysics Data System (ADS)

Ondrásková, Adriena; Bór, József; S[Breve]Evcík, Sebastián; Kostecký, Pavel; Rosenberg, Ladislav

2008-04-01

Superimposed on the continuous Schumann resonance (SR) background in the extremely low frequency (ELF) band, transient signals (e.g. bursts) can be observed, which originate from intense lightning discharges occurring at different locations on the globe. From the many transients that were observed at the Astronomical and Geophysical Observatory (AGO) of Comenius University near Modra, western Slovakia, in the vertical electric field component mainly during May and June of 2006, a peculiar group of events could be recognized. According to the waveform analysis, these peculiar events in most cases consist of two overlapping transients with a characteristic time difference of 0.13-0.15 s between the onsets. On the other hand, the spectrum of these peculiar transients showed discernible SR peaks for higher modes as well (n>7). The same events could be found in the records of the Széchenyi István Geophysical Observatory of the Geodetic and Geophysical Research Institute of the Hungarian Academy of Sciences near Nagycenk, Hungary (NCK). The natural origin of the peculiar events was verified from the NCK data and the source location was determined from the second transient. The results suggest that the two consecutive transients originated in the same thunderstorm. Furthermore, the phase spectrum analysis indicates that the sources have coherently excited the Earth-ionosphere cavity. These findings seem to support the idea that electromagnetic waves orbiting the Earth might trigger lightning discharges. The possibility that electromagnetic waves may trigger discharges was first considered by Nikola Tesla.

Glutathione aerosol suppresses lung epithelial surface inflammatory cell-derived oxidants in cystic fibrosis.

PubMed

Roum, J H; Borok, Z; McElvaney, N G; Grimes, G J; Bokser, A D; Buhl, R; Crystal, R G

1999-07-01

Cystic fibrosis (CF) is characterized by accumulation of activated neutrophils and macrophages on the respiratory epithelial surface (RES); these cells release toxic oxidants, which contribute to the marked epithelial derangements seen in CF. These deleterious consequences are magnified, since reduced glutathione (GSH), an antioxidant present in high concentrations in normal respiratory epithelial lining fluid (ELF), is deficient in CF ELF. To evaluate the feasibility of increasing ELF GSH levels and enhancing RES antioxidant protection, GSH aerosol was delivered (600 mg twice daily for 3 days) to seven patients with CF. ELF total, reduced, and oxidized GSH increased (P < 0.05, all compared with before GSH therapy), suggesting adequate RES delivery and utilization of GSH. Phorbol 12-myristate 13-acetate-stimulated superoxide anion (O2-.) release by ELF inflammatory cells decreased after GSH therapy (P < 0.002). This paralleled observations that GSH added in vitro to CF ELF inflammatory cells suppressed O2-. release (P < 0.001). No adverse effects were noted during treatment. Together, these observations demonstrate the feasibility of using GSH aerosol to restore RES oxidant-antioxidant balance in CF and support the rationale for further clinical evaluation.

Magnetite in human tissues: A mechanism for the biological effects of weak ELF magnetic fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirschvink, J.L.; Kobayashi-Kirschvink, A.; Diaz-Ricci, J.C.

1992-01-01

Due to the apparent lack of a biophysical mechanism, the question of whether weak, low-frequency magnetic fields are able to influence living organisms has long been one of the most controversial subjects in any field of science. However, two developments during the past decade have changed this perception dramatically, the first being the discovery that many organisms, including humans, biochemically precipitate the ferrimagnetic mineral magnetite (Fe3O4). In the magnetotactic bacteria, the geomagnetic response is based on either biogenic magnetite or greigite (Fe3S4), and reasonably good evidence exists that this is also the case in higher animals such as the honeymore » bee. Second, the development of simple behavioral conditioning experiments for training honey bees to discriminate magnetic fields demonstrates conclusively that at least one terrestrial animal is capable of detecting earth-strength magnetic fields through a sensory process. In turn, the existence of this ability implies the presence of specialized receptors which interact at the cellular level with weak magnetic fields in a fashion exceeding thermal noise. A simple calculation shows that magnetosomes moving in response to earth-strength ELF fields are capable of opening trans-membrane ion channels, in a fashion similar to those predicted by ionic resonance models. Hence, the presence of trace levels of biogenic magnetite in virtually all human tissues examined suggests that similar biophysical processes may explain a variety of weak field ELF bioeffects. 61 refs.« less

Occupational exposure to intermediate frequency and extremely low frequency magnetic fields among personnel working near electronic article surveillance systems.

PubMed

Roivainen, Päivi; Eskelinen, Tuomo; Jokela, Kari; Juutilainen, Jukka

2014-05-01

Cashiers are potentially exposed to intermediate frequency (IF) magnetic fields at their workplaces because of the electronic article surveillance (EAS) systems used in stores to protect merchandise against theft. This study aimed at investigating occupational exposure of cashiers to IF magnetic fields in Finnish stores. Exposure to extremely low frequency (ELF) magnetic fields was also evaluated because cashiers work near various devices operating with 50 Hz electric power. The peak magnetic flux density was measured for IF magnetic fields, and was found to vary from 0.2 to 4 µT at the cashier's seat. ELF magnetic fields from 0.03 to 4.5 µT were found at the cashier's seat. These values are much lower than exposure limits. However, according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) occupational reference levels for IF magnetic fields (141 µT for the peak field) were exceeded in some cases (maximum 189 µT) for short periods of time when cashiers walked through the EAS gates. As the ICNIRP reference levels do not define any minimum time for exposure, additional investigations are recommended to determine compliance with basic restrictions. Even if the basic restrictions are not exceeded, persons working near EAS devices represent an exceptional group of workers with respect to exposure to electromagnetic fields. This group could serve as a basis for epidemiological studies addressing possible health effects of IF magnetic fields. Compliance with the reference levels for IF fields was evaluated using both broadband measurement of peak fields and the ICNIRP summation rule for multiple frequencies. The latter was generally more conservative, and the difference between the two methods was large (>10-fold) for EAS systems using a 58 kHz signal with complex waveform. This indicates that the ICNIRP multiple frequency rule can be unnecessarily conservative when measuring complex waveforms. © 2014 Wiley Periodicals, Inc.

Napsin A levels in epithelial lining fluid as a diagnostic biomarker of primary lung adenocarcinoma.

PubMed

Uchida, Akifumi; Samukawa, Takuya; Kumamoto, Tomohiro; Ohshige, Masahiro; Hatanaka, Kazuhito; Nakamura, Yoshihiro; Mizuno, Keiko; Higashimoto, Ikkou; Sato, Masami; Inoue, Hiromasa

2017-12-12

It is crucial to develop novel diagnostic approaches for determining if peripheral lung nodules are malignant, as such nodules are frequently detected due to the increased use of chest computed tomography scans. To this end, we evaluated levels of napsin A in epithelial lining fluid (ELF), since napsin A has been reported to be an immunohistochemical biomarker for histological diagnosis of primary lung adenocarcinoma. In consecutive patients with indeterminate peripheral lung nodules, ELF samples were obtained using a bronchoscopic microsampling (BMS) technique. The levels of napsin A and carcinoembryonic antigen (CEA) in ELF at the nodule site were compared with those at the contralateral site. A final diagnosis of primary lung adenocarcinoma was established by surgical resection. We performed BMS in 43 consecutive patients. Among patients with primary lung adenocarcinoma, the napsin A levels in ELF at the nodule site were markedly higher than those at the contralateral site, while there were no significant differences in CEA levels. Furthermore, in 18 patients who were undiagnosed by bronchoscopy and finally diagnosed by surgery, the napsin A levels in ELF at the nodule site were identically significantly higher than those at the contralateral site. In patients with non-adenocarcinoma, there were no differences in napsin A levels in ELF. The area under the receiver operator characteristic curve for identifying primary lung adenocarcinoma was 0.840 for napsin A and 0.542 for CEA. Evaluation of napsin A levels in ELF may be useful for distinguishing primary lung adenocarcinoma.

Nuclear Weapons Effects Mitigation Techniques

DTIC Science & Technology

1982-06-01

ELF ) into the ultra-high (UHF) frequeniese, with much of Its energy concentrated In frequenrv ranges (high frequency (IF) into UHF) employed by Army...tactical Communications equipment. It Is of concern because the damage and upset it causes can occur Rt distances from the burst far beyond where...radiation is scattered from all directions, most of’ it comes from direct line-of-sight to the fireball. Therefore, the flat earth cover of an underground

Compilation of Annual Reports of the Navy ELF (Extremely Low Frequency) Communications System Ecological Monitoring Program (1983). Volume 2. Tabs F-J.

DTIC Science & Technology

1984-07-01

POSITAE C. rugosa *Arctiumn minus CON VOLULACEAE * .Centaurea maculosa , Convolviliis Cirsium arvense (several possible) C. discolor CRASSULACEAE C. hill...Heracleum lanatumn A. umbllatusHieraciumn aurantiacum - A. sp. I H. florentinumn A. sp. 2 H. pratense A. sp. 3 Hypericumn perforatumn Centaurea maculosa H...Hypericumn perforatumn Aster umbellatus Lychnis alba Aster sp. I Melilotus alba *Centaurea maculosa Oenethera biennis Chrysanthemum leucanthemnum Prunus

Effect of HF Heating Array Directivity Pattern on the Frequency Response of Generated ELF/VLF.

DTIC Science & Technology

1983-01-01

radiators ....... ............ 4 1-2 HF heating array ........ ................... 9 1-3 HF heating array element ...... ................ 9 1-4 View of top...elements looking down at pyramid ....... 9 1-5 Non-planar log-periodic antenna semi-structure dimensions ............ . ....... 10 l-6a Power gain vs...22 1-8 Orientation of 4- and 8-element arrays .. ......... .. 24 1- 9 Comparison of experimental and theoretical patterns. . . 27 1-10 Directive

Extremely Low Frequency (ELF) Communications Program: Non-Ionizing Electromagnetic Radiation Literature Evaluation and Assessment, 1986-1987 Literature Review.

DTIC Science & Technology

1987-11-01

and Carsteen E L (1985). Growth Rate and Mitotic Index Analysis of Vicia Faba L. Roots Exposed to 60-Hz Electric Fields. Bioelectromagnetics, Vol. 6...the observed effects. The mitotic index was also influenced. 5) In monkeys, central nervous system excitability was influenced by applying fields...Literature Search and Retrieval ...................... 16 2.2 Literature Culling and Indexing ...................... 18 2.3 Foreign Literature

Neuroendocrine mediated effects of electromagnetic-field exposure: Possible role of the pineal gland

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilson, W.B.; Stevens, R.G.; Anderson, L.E.

Reports from recent epidemiological studies have suggested a possible association between extremely low frequently (ELF; including 50- or 60-Hz) electric- and magnetic-field exposure, and increased risk of certain cancers, depression, and miscarriage. ELF field-induced pineal gland dysfunction is a possible etiological factor in these effects. Work in our laboratory and elsewhere has shown that ELF electromagnetic-field exposure can alter the normal circadian rhythm of melatonin synthesis and release in the pineal gland. Consequences of reduced or inappropriately timed melatonin release on the endocrine, neuronal, and immune systems are discussed. Laboratory data linking ELF field exposure to changes in pineal circadianmore » rhythms in both animal and humans are reviewed. The authors suggest that the pineal gland, in addition to being a convenient locus for measuring dyschronogenic effects of ELF field exposure, may play a central role in biological response to these fields via alterations in the melatonin signal.« less

Middle atmosphere electrical energy coupling

NASA Technical Reports Server (NTRS)

Hale, L. C.

1989-01-01

The middle atmosphere (MA) has long been known as an absorber of radio waves, and as a region of nonlinear interactions among waves. The region of highest transverse conductivity near the top of the MA provides a common return for global thunderstorm, auroral Birkeland, and ionospheric dynamo currents, with possibilities for coupling among them. Their associated fields and other transverse fields map to lower altitudes depending on scale size. Evidence now exists for motion-driven aerosol generators, and for charge trapped at the base of magnetic field lines, both capable of producing large MA electric fields. Ionospheric Maxwell currents (curl H) parallel to the magnetic field appear to map to lower altitudes, with rapidly time-varying components appearing as displacement currents in the stratosphere. Lightning couples a (primarily ELF and ULF) current transient to the ionosphere and magnetosphere whose wave shape is largely dependent on the MA conductivity profile. Electrical energy is of direct significance mainly in the upper MA, but electrodynamic transport of minor constituents such as smoke particles or CN may be important at other altitudes.

Anomalous geomagnetic variations associated with Parkfield (Ms=6.0, 28-SEP-2004, California, USA) earthquake

NASA Astrophysics Data System (ADS)

Kotsarenko, A. A.; Pilinets, S. A.; Perez Enriquez, R.; Lopez Cruz Abeyro, J. A.

2007-05-01

Analysis of geomagnetic and telluric data, measured at the station PRK (Parkfield, ULF flux-gate 3-axial magnetometer) 1 week before (including) the day of the major EQ (EarthQuake, Ms=6.0, 28-SEP-2004, 17:15:24) near Parkfield, California, USA, are presented. Spectral analysis reveal the ULF geomagnetic disturbances observed the day before the event, Sep 27, at 15:00- 20:00 by UT, and at the day of the EQ, Sep 28, at 11:00-19:00. Filtering in the corresponding frequency band f = 0.25-0.5 Hz gives the following estimations of the amplitudes of the signals: up to 20 pT for the magnetic channels and 1.5 mkV/km for the telluric ones. Observed phenomena occurs under quiet geomagnetic conditions (|Dst|<20 nT); revision of the referent stations data situated far away from the EQ epicenter (330 km) does not reveal any similar effect. Moreover, the Quake Finder research group (http:www.quakefinder.com) received very similar results (ELF range instrument, placed about 50 km from the EQ epicenter) for the day of the EQ. Mentioned above suggests the localized character of the source, possibly of the ionosphere or tectonic origin rather than of magnetosphere. Comparative analysis of the mentioned 2 stations show that we observed the lower-frequency part of the ULF- ELF burst, localized in the frequency range 0.25-1 Hz, generated 9 hours before the earthquake. Acknowledgements. The authors are grateful to Malcolm Johnston for providing us with the geomagnetic data.

Electromagnetic plasma wave emissions from the auroral field lines

NASA Technical Reports Server (NTRS)

Gurnett, D. A.

1977-01-01

The most important types of auroral radio emissions are reviewed, both from a historical perspective as well as considering the latest results. Particular emphasis is placed on four types of electromagnetic emissions which are directly associated with the plasma on the auroral field lines. These emissions are (1) auroral hiss, (2) saucers, (3) ELF noise bands, and (4) auroral kilometric radiation. Ray tracing and radio direction finding measurements indicate that both the auroral hiss and auroral kilometric radiation are generated along the auroral field lines relatively close to the earth, at radial distances from about 2.5 to 5 R sub e. For the auroral hiss the favored mechanism appears to be amplified Cerenkov radiation. For the auroral kilometric radiation several mechanisms have been proposed, usually involving the intermediate generation of electrostatic waves by the precipitating electrons.

ELF (Extremely Low Frequency) Communications System - Ecological Monitoring Program: Summary of 1988 Progress

DTIC Science & Technology

1989-11-01

of fresh leaves are fast at both sites. 3 Similar comparisons using autumn abscised leaves show intermediate processing rates at the treatment site...processing fresh or autumn- abscised leaves during 1988 (t-test). Analyses of variance showed that fresh leaves were pricessed significantly faster at the...Northern Journal of Applied Forestry, 5:14, 1988. 22 Connaughton, P. The effects of acid precipi*ation on nutrient levels in a forest soil and foliage of

Localized Elf Propagation Anomalies.

DTIC Science & Technology

1985-06-01

the above three SPEs. Those important auxiliary data are used as inputs to air- chemistry codes to calculate the electron and ion density height...horizontal magnetic intensity H is H A ( ATAR ) 1 / 2 (9 d)- 1/2 exp(-’afL- d) e- d/ 8 " 7 coso A/m, (1) where A depends on the antenna moment, frequency...those rates are input to air- chemistry equations to obtain height profiles of electron and ion densities. Calculation of ion-pair production rates

Residential exposure to extremely low-frequency magnetic fields and risk of childhood leukaemia, CNS tumour and lymphoma in Denmark.

PubMed

Pedersen, Camilla; Johansen, Christoffer; Schüz, Joachim; Olsen, Jørgen H; Raaschou-Nielsen, Ole

2015-11-03

We previously reported that children exposed to elevated extremely low-frequency magnetic fields (ELF-MF) had a five to six times higher risk of leukaemia, central nervous system (CNS) tumour and malignant lymphoma. Here we extend the study from 1968 to 1986 through 2003. We included 3277 children with leukaemia, CNS tumour or malignant lymphoma during 1968-2003 recorded in the Danish Cancer Registry and 9129 controls randomly selected from the Danish childhood population. ELF-MF from 50 to 400 kV facilities were calculated at the residences. For recently diagnosed cases (1987-2003), the relative risk (RR) was 0.88 (95% confidence interval (CI): 0.32-2.42), while for the total period (1968-2003) it was 1.63 (95% CI: 0.77-3.46) for leukaemia, CNS tumour and malignant lymphoma combined for exposures ⩾0.4 μT compared with <0.1 μT. These results were based on five cases (recent period) and 11 cases (total period) in the highest exposure group. We did not confirm the previous finding of a five- to six-fold higher risk for leukaemia, CNS tumour and malignant lymphoma when including data from the more recent time period. For the total time period, the results for childhood leukaemia were in line with large pooled analyses showing RRs between 1.5 and 2.

Winding a Long Coil with a Pre-Programmed Turns Density Variation

DTIC Science & Technology

1975-05-27

turns den- sity is to follow. A machine having this capability is needed to provide a towed ELF loop antenna with the smoothly tapered sensitivity...Introduction A submarine towed ELF loop antenna vibrates longitudinally and trans- versely during towing. The vibration is driven by the fluctuating surface...in attaining the smoothly varying turns density required for the signal winding of a towed ELF loop antenna . Acknowledgments Thanks are due to John

High Performance Databases For Scientific Applications

NASA Technical Reports Server (NTRS)

French, James C.; Grimshaw, Andrew S.

1997-01-01

The goal for this task is to develop an Extensible File System (ELFS). ELFS attacks the problem of the following: 1. Providing high bandwidth performance architectures; 2. Reducing the cognitive burden faced by applications programmers when they attempt to optimize; and 3. Seamlessly managing the proliferation of data formats and architectural differences. The approach for ELFS solution consists of language and run-time system support that permits the specification on a hierarchy of file classes.

Numerical Simulation of the Variation of Schumann Resonance Associated with Seismogenic Processe in the Lithosphere-Atmosphere-Ionosphere system

NASA Astrophysics Data System (ADS)

Liu, L.; Huang, Q.; Wang, Y.

2012-12-01

The variations in the strength and frequency shift of the Schumann resonance (SR) of the electromagnetic (EM) field prior to some significance earthquakes were reported by a number of researchers. As a robust physical phenomenon constantly exists in the resonant cavity formed by the lithosphere-atmosphere-ionosphere system, irregular variations in SR parameters can be naturally attributed to be the potential precursory observables for forecasting earthquake occurrences. Schumann resonance (SR) of the EM field between the lithosphere and the ionosphere occurs because the space between the surface of the Earth and the conductive ionosphere acts as a closed waveguide. The cavity is naturally excited by electric currents generated by lightning. SR is the principal background in the electromagnetic spectrum at extremely low frequencies (ELF) between 3-69 Hz. We simulated the EM field in the lithosphere-ionosphere waveguide with a 2-dimensional (2D), cylindrical whole-earth model by the hybrid pseudo-spectral and finite difference time domain method. Considering the seismogensis as a fully coupled seismoelectric process, we simulate the seismic wave and EM wave in this 2D model. The excitation of SR in the background EM field are generated by the electric-current impulses due to lightning thunderstorms within the lowest 10 kilometers of the atmosphere . The diurnal variation and the latitude-dependence in ion concentration in the ionosphere are included in the model. After the SR has reached the steady state, the impulse generated by the seismogenic process (pre-, co- and post-seismic) in the crust is introduced to assess the possible precursory effects on SR strength and frequency. The modeling results explain the observed fact of why SR has a much more sensitive response to continental earthquakes, and much less response to oceanic events; the reason is simply due to the shielding effect of the conductive ocean that prevents effective radiation of the seismoelectric signals into the lithosphere- ionosphere waveguide.; Resonance cavity model formed by the lithosphere-atmosphere-ionosphere system (illustrative, not to the scale of the Earth).

A Collaborative Approach for Providing Low-Cost ELF Monitoring from Ground and Space

NASA Astrophysics Data System (ADS)

Bleier, T. E.; Franklin, L.

2003-12-01

This paper describes a collaborative effort among several groups, including a small business (QuakeFinder,LLC), dozens of high schools in northern California, several universities (Stanford and Cal Poly SLO), and Lockheed Martin in Sunnyvale to build a combined ground-based and space-based ELF monitoring system. The goal is to monitor and characterize the raw RF spectrum in the ELF band, and to look for pre- and post-earthquake signatures. Previous attempts at monitoring ELF signals associated with earthquakes have always been summarized with the statement, more data is needed. QuakeFinder is a small business that approached the problem with a different strategy. Rather than deploy a few, expensive, commercial high sensitivity, AC magnetometers on the ground, a collaboration was formed with high school physics classes to build a large number of medium sensitivity magnetometers from partially-assembled kits, and to deploy these sensors in a close spacing along the major California earthquake faults. The strategy was to have a 3-axis ELF ground monitor within 15 km of any large (>M5) quake-- before, during, and after the event. To date, 34 sites have been deployed (out of 50 planned), and they now collect and display daily averages from these 3-axis monitors on a web site (www.earthquaketracker.com). Likewise, satellite-based monitoring is severely restricted by the high cost of building and flying space-based ELF monitors. QuakeFinder formed a collaboration between Stanford Space System Development Laboratory and Lockheed Martin to design and build a nano-satellite (4.5 kg) whose mission was to collect ELF background signatures. QuakeFinder built and donated a single axis ELF (1-1000Hz) magnetometer payload and provided integration and a launch opportunity for "QuakeSat I". The satellite was launched on June 30, 2003 into a 820 km circular polar orbit, and has recorded natural signals (lightning, whistlers, auroral noise, and several unidentified signatures) as well as man-made (radar) signals. At this writing, it is early in the project, and more signal analysis and statistics are needed to determine if earthquake-related signals are present. The paper will report on the result of QuakeSat tasking over epicenters of >M6 earthquakes for post seismic correlations, and over seismically active areas worldwide for pre-seismic correlations of increasing ELF signals.

What do patients know? Education from the European Lung Foundation perspective.

PubMed

Powell, Pippa; Smyth, Dan; Saraiva, Isabel; Lisspers, Karin; Hardavella, Georgia; Fuertes, Juan; Hill, Kate

2018-03-01

The European Lung Foundation (ELF) is an organisation whose mission is to bring together the public and patients with respiratory professionals to improve lung health. A core part of all its activities focus on education: the education of patients on their condition, including how to prevent, treat and manage it; the education of healthcare professionals on how to improve work with patients and awareness about the issues that are important to patients; and education of the public and policy makers of the importance of lung health at a European level. ELF was founded and works in a unique partnership with the European Respiratory Society (ERS). This article has been written by the recent past Chairs and the new Chairs of three ELF committees (Council (D. Smyth and I. Saraiva), Professional Advisory Committee (K. Lisspers and G. Hardavella) and Patient Advisory Committee (J. Fuertes and K. Hill)) in order to reflect on ELF's journey in this regard over recent years. In particular, it seems a good moment to assess the success and impact of the first patient Chair of ELF, Dan Smyth, and reflect on what this has meant for ELF's educational activities, and what the future now looks like. To understand the importance of educated patients (patients that are knowledgeable on their condition and how healthcare processes work).To understand the importance of guiding patients to quality reliable sources of information and education.To establish ways to ensure that healthcare professionals are prepared to work with educated patients.To outline the initiatives that ELF has driven forward in the field of education.To see the value in patients advocating at the European level for raising standards of education for patients and physicians.

"They Can Achieve Their Aims without Native Skills in the Field of Work or Studies": Hungarian Students' Views on English as a Lingua Franca

ERIC Educational Resources Information Center

Kontra, Edit H.; Csizér, Kata

2011-01-01

Despite the fact that there is a growing body of research on the characteristics and use of English as a lingua franca (ELF) in Europe, there are relatively few studies aimed at investigating the ways in which language learners voice their opinions about ELF and how they see ELF impacting their own learning. Therefore, the aim of the present study…

EARLY FLOWERING3 Regulates Flowering in Spring Barley by Mediating Gibberellin Production and FLOWERING LOCUS T Expression[C][W

PubMed Central

Boden, Scott A.; Weiss, David; Ross, John J.; Davies, Noel W.; Trevaskis, Ben; Chandler, Peter M.; Swain, Steve M.

2014-01-01

EARLY FLOWERING3 (ELF3) is a circadian clock gene that contributes to photoperiod-dependent flowering in plants, with loss-of-function mutants in barley (Hordeum vulgare), legumes, and Arabidopsis thaliana flowering early under noninductive short-day (SD) photoperiods. The barley elf3 mutant displays increased expression of FLOWERING LOCUS T1 (FT1); however, it remains unclear whether this is the only factor responsible for the early flowering phenotype. We show that the early flowering and vegetative growth phenotypes of the barley elf3 mutant are strongly dependent on gibberellin (GA) biosynthesis. Expression of the central GA biosynthesis gene, GA20oxidase2, and production of the bioactive GA, GA1, were significantly increased in elf3 leaves under SDs, relative to the wild type. Inhibition of GA biosynthesis suppressed the early flowering of elf3 under SDs independently of FT1 and was associated with altered expression of floral identity genes at the developing apex. GA is also required for normal flowering of spring barley under inductive photoperiods, with chemical and genetic attenuation of the GA biosynthesis and signaling pathways suppressing inflorescence development under long-day conditions. These findings illustrate that GA is an important floral promoting signal in barley and that ELF3 suppresses flowering under noninductive photoperiods by blocking GA production and FT1 expression. PMID:24781117

A Search for Signatures of Ion Acoustic Shoulders in the SERSIO sounding rocket data set

NASA Astrophysics Data System (ADS)

Ellis, A. T.; Lessard, M. R.; Kintner, P. M.; Lynch, K. A.; Klatt, E.; Oksavik, K.

2004-12-01

Although first predicted in the early 1960's, enhanced Ion Acoustic Shoulders have only been observed by incoherent scatter radars since the late 1980's. The signature of an IAS is seen as a positive and negative frequency shift about the center radar frequency. These features occur at altitudes of 150 to over 600 km, peaking at 500 km, with spatial extent (perpendicular to the magnetic field) the order of 10 km. The occurrence distribution shows a maximum in the pre-midnight region, with a secondary peak on the dayside (Rietveld et al 1995). Observations of strong (1000 mA/m2), localized currents by EISCAT have led to theories based on current-driven instabilities as the source of these waves (Forme, 1993; St.-Maurice et al., 1996). The SERSIO (Svalbard EISCAT Rocket Study of Ion Outflows) sounding rocket mission was launched into CME-driven dayside aurora on the 22nd of January 2004 at 0857 UT (0436 MLT) from Ny-Alesund (78o 55' 11" N, 11o 56' 60" E) and reached an apogee of 782 km. During the flight, the EISCAT incoherent scatter radar network supported the mission by monitoring altitude profiles of electron and ion density, velocity and temperature. From Longyearbyen, located approximately 50 km south east of Ny-Alesund and near the trajectory of SERSIO, the 32m ESR dish was tracking the ionospheric footprint of the payload while the 42 m dish was making local field-aligned measurements. The data from these radars clearly indicated the presence of enhanced ion acoustic shoulders, suggesting that SERSIO flew through a 'field' of Ion Acoustic Shoulders. In fact, the plasma wave environment observed by SERSIO was composed of traditional VLF hiss and Broad Band ELF hiss with wavelengths less than the order of 6m. Here we present the result of our search for Ion Acoustic Shoulders in the SERSIO data set.

Experimental study of ELF signatures developed by ballistic missile launch

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peglow, S.G.; Rynne, T.M.

1993-04-08

The Lawrence Livermore National Laboratory (Livermore, CA) and SARA, Inc. participated in the ATMD missile launch activities that occurred at WSMR during January 1993. These tests involved the launch of Lance missiles with a subsequent direction of F-15Es into the launch area for subsequent detection and simulated destruction of redeployed missile launchers, LLNL and SARA deployed SARN`s ELF sensors and various data acquisition systems for monitoring of basic phenomena. On 25 January 1993, a single missile launch allowed initial measurements of the phenomena and an assessment of appropriate sensor sensitivity settings as well as the appropriateness of the sensor deploymentmore » sites (e.g., with respect to man-made ELF sources such as power distributions and communication lines). On 27 January 1993, a measurement of a double launch of Lance missiles was performed. This technical report covers the results of the analysis of latter measurements. An attempt was made to measure low frequency electromagnetic signatures that may be produced during a missile launch. Hypothetical signature production mechanisms include: (1) Perturbations of the earth geo-potential during the launch of the missile. This signature may arise from the interaction of the ambient electric field with the conducting body of the missile as well as the partially ionized exhaust plume. (2) Production of spatial, charge sources from triboelectric-like mechanisms. Such effects may occur during the initial interaction of the missile plume with the ground material and lead to an initial {open_quotes}spike{close_quotes} output, Additionally, there may exist charge transfer mechanisms produced during the exhausting of the burnt fuel oxidizer.« less

Compilation of 1990 annual reports of the Navy ELF communications system ecological monitoring program. Volume 2: Tabs C thru F

NASA Astrophysics Data System (ADS)

Zapotosky, J. E.

1991-08-01

This portion of the report includes monitoring of and data for arthropoda and earthworms; pollinating insects; and small mammals and nesting birds. During the 1990 growing season the ELF antenna was operated more frequently than in prior years. This provides 2 years of intermittent ELF exposure for the biological systems to react to the radiation, one year of very limited exposure and greater exposure in 1990. Arthropod and earthworm sampling was conducted at intervals of two weeks from early May to late October. High voltage transmission lines and magnetic fields have been shown to affect honeybee reproduction, survival, orientation, and nest structure. ELF EM fields could have similar effects on native megachild bees. Changes in cell length, number of cells per nest, number of leaver per cell, orientation of nest entrances, and time to collect a round leaf pierce to cap a cell were monitored. We have not detected significant changes that could be attributed to ELF EM fields. Small mammal and nesting bird biological studies in the western Upper Peninsula of Michigan for the year 1990 are reported.

EARLY FLOWERING3 Redundancy Fine-Tunes Photoperiod Sensitivity1[OPEN

PubMed Central

Rubenach, Andrew J.S.; Vander Schoor, Jacqueline K.; Aubert, Gregoire; Burstin, Judith

2017-01-01

Three pea (Pisum sativum) loci controlling photoperiod sensitivity, HIGH RESPONSE (HR), DIE NEUTRALIS (DNE), and STERILE NODES (SN), have recently been shown to correspond to orthologs of Arabidopsis (Arabidopsis thaliana) circadian clock genes EARLY FLOWERING3 (ELF3), ELF4, and LUX ARRHYTHMO, respectively. A fourth pea locus, PHOTOPERIOD (PPD), also contributes to the photoperiod response in a similar manner to SN and DNE, and recessive ppd mutants on a spring-flowering hr mutant background show early, photoperiod-insensitive flowering. However, the molecular identity of PPD has so far remained elusive. Here, we show that the PPD locus also has a role in maintenance of diurnal and circadian gene expression rhythms and identify PPD as an ELF3 co-ortholog, termed ELF3b. Genetic interactions between pea ELF3 genes suggest that loss of PPD function does not affect flowering time in the presence of functional HR, whereas PPD can compensate only partially for the lack of HR. These results provide an illustration of how gene duplication and divergence can generate potential for the emergence of more subtle variations in phenotype that may be adaptively significant. PMID:28202598

Could Magnetic Fields Affect the Circadian Clock Function of Cryptochromes? Testing the Basic Premise of the Cryptochrome Hypothesis (ELF Magnetic Fields).

PubMed

Vanderstraeten, Jacques; Burda, Hynek; Verschaeve, Luc; De Brouwer, Christophe

2015-07-01

It has been suggested that weak 50/60 Hz [extremely low frequency (ELF)] magnetic fields (MF) could affect circadian biorhythms by disrupting the clock function of cryptochromes (the "cryptochrome hypothesis," currently under study). That hypothesis is based on the premise that weak (Earth strength) static magnetic fields affect the redox balance of cryptochromes, thus possibly their signaling state as well. An appropriate method for testing this postulate could be real time or short-term study of the circadian clock function of retinal cryptochromes under exposure to the static field intensities that elicit the largest redox changes (maximal "low field" and "high field" effects, respectively) compared to zero field. Positive results might encourage further study of the cryptochrome hypothesis itself. However, they would indicate the need for performing a similar study, this time comparing the effects of only slight intensity changes (low field range) in order to explore the possible role of the proximity of metal structures and furniture as a confounder under the cryptochrome hypothesis.

Extreme Low Frequency Acoustic Measurement System

NASA Technical Reports Server (NTRS)

Shams, Qamar A. (Inventor); Zuckerwar, Allan J. (Inventor)

2017-01-01

The present invention is an extremely low frequency (ELF) microphone and acoustic measurement system capable of infrasound detection in a portable and easily deployable form factor. In one embodiment of the invention, an extremely low frequency electret microphone comprises a membrane, a backplate, and a backchamber. The backchamber is sealed to allow substantially no air exchange between the backchamber and outside the microphone. Compliance of the membrane may be less than ambient air compliance. The backplate may define a plurality of holes and a slot may be defined between an outer diameter of the backplate and an inner wall of the microphone. The locations and sizes of the holes, the size of the slot, and the volume of the backchamber may be selected such that membrane motion is substantially critically damped.

Extreme low frequency acoustic measurement system

NASA Technical Reports Server (NTRS)

Shams, Qamar A. (Inventor); Zuckerwar, Allan J. (Inventor)

2013-01-01

The present invention is an extremely low frequency (ELF) microphone and acoustic measurement system capable of infrasound detection in a portable and easily deployable form factor. In one embodiment of the invention, an extremely low frequency electret microphone comprises a membrane, a backplate, and a backchamber. The backchamber is sealed to allow substantially no air exchange between the backchamber and outside the microphone. Compliance of the membrane may be less than ambient air compliance. The backplate may define a plurality of holes and a slot may be defined between an outer diameter of the backplate and an inner wall of the microphone. The locations and sizes of the holes, the size of the slot, and the volume of the backchamber may be selected such that membrane motion is substantially critically damped.

Compilation of 1989 Annual Reports of the Navy ELF Communications System Ecological Monitoring Program. Volume 2. Tabs C-F

DTIC Science & Technology

1990-08-01

in ecological communities such as those in the vicinity of the ELF antenna because they are pollinators of flowering plants , and are therefore...I I IITRI E06620-4 Page v I I ELF COMMUNICATIONS SYSTEM ECOLOGICAL MONITORING PROGRAM I INDEX OF 1989 ANNUAL REPORTS I A. Herbaceous Plant Cover and...Communications System Ecological Monitoring Program; BIOLOGICAL STUDIES ON POLLINATING INSECTS: MEGACHILID BEES Reporting year: 11/1/88 - 10/31/89 5 Prepared by

Effect of glutathione aerosol on oxidant-antioxidant imbalance in idiopathic pulmonary fibrosis.

PubMed

Borok, Z; Buhl, R; Grimes, G J; Bokser, A D; Hubbard, R C; Holroyd, K J; Roum, J H; Czerski, D B; Cantin, A M; Crystal, R G

1991-07-27

Idiopathic pulmonary fibrosis (IPF) is characterised by alveolar inflammation, exaggerated release of oxidants, and subnormal concentrations of the antioxidant glutathione in respiratory epithelial lining fluid (ELF). Glutathione (600 mg twice daily for 3 days) was given by aerosol to 10 patients with IPF. Total ELF glutathione rose transiently, ELF oxidised glutathione concentrations increased, and there was a decrease in spontaneous superoxide anion release by alveolar macrophages. Thus, glutathione by aerosol could be a means of reversing the oxidant-antioxidant imbalance in IPF.

Electromagnetic Pulse (EMP) from the Magnetic Bubble Source as a Discriminator of Underground Nuclear Explosions, Including Cavity Decoupling

DTIC Science & Technology

2011-02-01

planned shock physics experiments (SPE) 4. Design/develop a very low frequency (VLF)/ELF pulsar to serve as an underground calibration source 5...Carry out underground (in tunnels, etc.) pulsar calibration experiments  A-1 APPENDIX A. ABBREVIATIONS AND ACRONYMS CORRTEX Continuous Reflectometry...Site Office P.O. Box 98521 M/S NLV 101 Las Vegas, NV 89193-8521 ATTN: Ping Lee 1 Los Alamos National Laboratory PO Box 1663 Los Alamos, NM 87545

Final Technical Report for ELF/VLF Electromagnetic Detection and Characterization of Deeply Buried Targets

DTIC Science & Technology

1998-06-22

remote (e.g. HAARP /HIPAS), and natural sources (e.g. external noise); b) model the perturbed fields due to the specified underground structures...examined in this study are of three types • Remote man-made sources, e.g. HAARP /HIPAS • Local sources, e.g. metal-detector loop • Natural sources, e.g...The High Power Auroral Stimulation Observatory (HIPAS) and the High Frequency Active Auroral Research Program ( HAARP ) are capable of exciting plasma

Compilation of Annual Reports of the Navy ELF (Extremely Low Frequency) Communications System Ecological Monitoring Program. Volume 1. Tabs A-E.

DTIC Science & Technology

1984-07-01

mhhhhmhhmmm EEmhohEEmhmhEE EohhEohEEEEohI 1111 11111_L25 1.18 6 MICROCOPY RESOLUTION TESI CHART 95. Pedon Classification: Typic Dystrochrept, sandy, mixed...prepared by team researchers in the MTU Forestry Department and delivered to the Environmental Microbiology lab in the Department of Biological Sciences...unsuccessful. Using methods given in a presentation at the 1982 American Society for Microbiology Annual Meetings, virtually no bacteria of any type were

Compilation of 1987 Annual Reports of the Navy ELF (Extremely Low Frequency) Communications System Ecological Monitoring Program. Volume 1

DTIC Science & Technology

1988-08-01

was used to: 1) develop functions using species importance values from pretreatment years (1985 and 1986) and 2) determine if discriminant functions...degrade lignocellulose . L -7- During 1988, this work element will focus on two objec- tives: 1) obtaining the first year’s data on streptomycete...cellulose, and lignin/ lignocellulose in both coniferous and deci- duous litter systems (Graustein gt &. 1977, Crawford 1978, Knut- son &I jL. 1980

Compilation of 1986 Annual Reports of the Navy ELF (Extremely Low Frequency) Communications System Ecological Monitoring Program. Volume 1. TABS A-C.

DTIC Science & Technology

1987-07-01

temperature increase ccrnpared to the antenna plantation while the control pole-size stand type had a -.3’ decrease. These relationships emphasize ...study of the timing of life cycle events relative to environmental cues (Barbour et al. 1980), has been used to quantitatively describe the herbaceous...successful, emphasizing the importance of ainual weather patterns on the buildup of microbial populations and their activities. These analyses indicate

Extremely Low Frequency (ELF) Vertical Electric Field Exposure of Rats: Irradiation Facility

DTIC Science & Technology

1977-05-01

altered inside an animal cage even with wet or dry litter and full food and water containers. Rats weighing approximately 300 g in adjacent cages caused...with guard circuit Field inside empty cage Field inside complete cage ( litter (wet or dry) + food + water) Field variations caused by 300 g rat...blanket 250 Iron 60 Broiler 130 Hair dryer 40 Vaporizer 40 Refrigerator 60 Color TV 30 Stereo 90 Coffee pot 30 Vacuum cleaner 16 Clock radio

Compilation of 1988 Annual Reports of the Navy ELF (Extremely Low Frequency) Communications System Ecological Monitoring Program. Volume 3

DTIC Science & Technology

1989-08-01

describing structural features of the habitat and 9 describing abundance of I dominant tree species) to a smaller set of uncorrelated variables that 3...support more deciduous habitats I (Blake et al. 1988). Differences in a variety of other habitat features also occur, but the deciduous-coniferous...Bradley, and S.R. Daruvalla. 1972. Influence of low level electronic and magnetic fields on the growth of young chickens. Biomed . Sci. Instrum. 9: 183

Compilation of 1986 Annual Reports of the Navy ELF (Extremely Low Frequency) Communications System Ecological Monitoring Program. Volume 3. TABS H-J.

DTIC Science & Technology

1987-07-01

yearly trends, and the effect of population size and abiotic factors on growth will be completed when the 1984-1986 scales are completed. Fish condition...settling of suspended particles on substrates in its absence. The pumps were powered by a heavy duty marine battery which had to be exchanged and...computer using procedures available in SPSS (Hull and Nie 1981) and programs available in the BIOM statistical package (Rohlf). Sokal and Rohlf (1981

Compilation of 1988 Annual Reports of the Navy ELF (Extremely Low Frequency) Communications System Ecological Monitoring Program. Volume 2

DTIC Science & Technology

1989-08-01

i3, 112-119. SW~right, R.T. & Coffin, R.B. 1984. Measuring microzopl , ’-., grazing on planktonic marine bacteria bv its impact on bacteria...activities are 3 shown for 1987 in Figure 4, along with antenna on and off times. Testing of the antenna was conducted on a 33% time rotation schedule...noticed that different observers differ slightly in their techniques for measuring 3 weights and body parts. Therefore we had all observers rotate among

ELF5 in epithelial ovarian carcinoma tissues and biological behavior in ovarian carcinoma cells.

PubMed

Yan, Hongchao; Qiu, Linglin; Xie, Xiaolei; Yang, He; Liu, Yongli; Lin, Xiaoman; Huang, Hongxiang

2017-03-01

The expression of E74-like factor 5 (ELF5) in epithelial ovarian carcinoma tissues and its effects on biological behavior in ovarian carcinoma cells were assessed in search for a new approach for gene treatment of epithelial ovarian carcinoma. RT-PCR technology was applied to detect the expression of ELF5 mRNA in epithelial ovarian carcinoma (n=49), borderline ovarian epithelial tumor (n=19), benign ovarian epithelial tumor (n=31) and normal ovarian tissues (n=40). Then, we transfected recombinant plasmid pcDNA3.1‑ELF5+EGFP into human ovarian carcinoma SKOV3 cells (recombinant plasmid group) in vitro and screened out stably transfected cells to conduct multiplication culture. Western blot analysis was performed to detect the expression of ELF5 protein in the different groups. Flow cytometry was employed to detect cell apoptosis and cycles. ELF5 mRNA in epithelial ovarian carcinoma and borderline ovarian epithelial tumor tissues were significantly lower (P<0.05) than those in benign ovarian epithelial tumor and normal ovarian tissues. ELF5 protein expression in the cells of recombinant plasmid group was significantly higher compared with empty plasmid and blank control groups. The capacity of cell reproductive recombinant plasmid group at each time point decreased (P<0.05). Flow cytometry detection showed that 67.03% of cells in recombinant plasmid group was blocked in G0/G1 phase (P<0.05), compared with empty plasmid group (37.17%) and blank control group (38.24%). Apoptotic rate of recombinant plasmid group was significantly lower (31.4±1.9%; P<0.05), compared with that of empty plasmid group (9.1±2.2%) and blank control group (8.7±1.5%), and the differences were statistically significant. In conclusion, ELF5 interfered with cell cycle of human ovarian carcinoma SKOV3 cells and promoted apoptosis of human ovarian carcinoma SKOV3 cells inhibiting their growth and invasive capacity; and thus providing a new approach to gene treatment of ovarian carcinoma.

Patient assessment of medication information leaflets and validation of the Evaluative Linguistic Framework (ELF).

PubMed

Hirsh, Di; Clerehan, Rosemary; Staples, Margaret; Osborne, Richard H; Buchbinder, Rachelle

2009-11-01

To obtain patient feedback about the structure and quality of medication information leaflets and validate the usefulness of the Evaluative Linguistic Framework (ELF) for improving written communication with patients. Triangulated feedback about a set of rheumatoid arthritis (RA) medication leaflets, some developed with knowledge of the ELF, was obtained from 27 people with RA from interviews, focus group discussion and self-administered questionnaires. The principal elements of the framework were investigated: overall generic structure and functions of each stage, interpersonal relationship between writer and reader, technicality of language and density of information. Participant assessments of the leaflets aligned with the framework in terms of what constituted a good leaflet. While the main purpose of the leaflets was identified as being information provision, participants also wanted clear instructions, benefits to be highlighted and side effects to be comprehensively listed. For comprehensiveness and user-friendliness, leaflets developed with guidance of the ELF were consistently preferred. According to people with RA, leaflets generated from a linguistic framework are clearer and more effective in communicating information about medications. The ELF is a user-friendly, structured analytic system that can assist with the development of effective high quality patient information materials.

Compilation of 1990 annual reports of the Navy ELF Communications System Ecological-Monitoring Program. Volume 2. Tabs C thru F. Annual report, Jan-Dec 90

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zapotosky, J.E.

1991-08-01

This portion of the report includes monitoring of and data for arthropoda and earthworms; pollinating insects; and small mammals and nesting birds. During the 1990 growing season the ELF antenna was operated more frequently than in prior years. This provides 2 years of intermittent ELF exposure for the biological systems to react to the radiation, one year of very limited exposure and greater exposure in 1990. Arthropod and earthworm sampling was conducted at intervals of two weeks from early May to late October. High voltage transmission lines and magnetic fields have been shown to affect honeybee reproduction, survival, orientation, andmore » nest structure. ELF EM fields could have similar effects on native megachild bees. Changes in cell length, number of cells per nest, number of leaver per cell, orientation of nest entrances, and time to collect a round leaf pierce to cap a cell were monitored. We have not detected significant changes that could be attributed to ELF EM fields. Small mammal and nesting bird biological studies in the western Upper Peninsula of Michigan for the year 1990 are reported.« less

Aliasing of the Schumann resonance background signal by sprite-associated Q-bursts

NASA Astrophysics Data System (ADS)

Guha, Anirban; Williams, Earle; Boldi, Robert; Sátori, Gabriella; Nagy, Tamás; Bór, József; Montanyà, Joan; Ortega, Pascal

2017-12-01

The Earth's naturally occurring Schumann resonances (SR) are composed of a quasi-continuous background component and a larger-amplitude, short-duration transient component, otherwise called 'Q-burst' (Ogawa et al., 1967). Sprites in the mesosphere are also known to accompany the energetic positive ground flashes that launch the Q-bursts (Boccippio et al., 1995). Spectra of the background Schumann Resonances (SR) require a natural stabilization period of ∼10-12 min for the three conspicuous modal parameters to be derived from Lorentzian fitting. Before the spectra are computed and the fitting process is initiated, the raw time series data need to be properly filtered for local cultural noise, narrow band interference as well as for large transients in the form of global Q-bursts. Mushtak and Williams (2009) describe an effective technique called Isolated Lorentzian (I-LOR), in which, the contributions from local cultural and various other noises are minimized to a great extent. An automated technique based on median filtering of time series data has been developed. These special lightning flashes are known to have greater contribution in the ELF range (below 1 kHz) compared to general negative CG strikes (Huang et al., 1999; Cummer et al., 2006). The global distributions of these Q-bursts have been studied by Huang et al. (1999) Rhode Island, USA by wave impedance methods from single station ELF measurements at Rhode Island, USA and from Japan Hobara et al. (2006). The present work aims to demonstrate the effect of Q-bursts on SR background spectra using GPS time-stamped observation of TLEs. It is observed that the Q-bursts selected for the present work do alias the background spectra over a 5-s period, though the amplitudes of these Q-bursts are far below the background threshold of 16 Core Standard Deviation (CSD) so that they do not strongly alias the background spectra of 10-12 min duration. The examination of one exceptional Q-burst shows that appreciable spectral aliasing can occur even when 12-min spectral integrations are considered. The statistical result shows that for a 12-min spectrum, events above 16 CSD are capable of producing significant frequency aliasing of the modal frequencies, although the intensity aliasing might have a negligible effect unless the events are exceptionally large (∼200 CSD). The spectral CSD methodology may be used to extract the time of arrival of the Q-burst transients. This methodology may be combined with a hyperbolic ranging, thus becoming an effective tool to detect TLEs globally with a modest number of networked observational stations.

Compilation of 1989 annual reports of the Navy ELF Communications System Ecological Monitoring Program. Volume 2. tabs C-F. Annual progress report, Jan-Dec 89

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1990-08-01

This is the eighth compilation of annual reports for the Navy's ELF Communications Systems Ecological Monitoring Program. The reports document the progress of eight studies performed during 1989 near the Naval Radio Transmitting Facility -- Republic, Michigan. The purpose of the monitoring is to determine whether electromagnetic fields produced by the ELF Communications System will affect resident biota or their ecological relationships. Soil Amoeba: Arthropoda and Earthworms: Pollinating Insects: Small Mammals and Nesting Birds.

Compendium of the ULF/ELF Electromagnetic Fields Generated above a Sea of Finite Depth by Submerged Harmonic Dipoles

DTIC Science & Technology

1980-01-01

CATALOG NUMBER Tech. Report No. E715-1 4. TTE (ln tlitts LTYPE RPOT’ QcOIJj. Compendium of the ULF/ELF Electromagnetic Fields nccnicat Generated above...sidi if noeess’ry arid Identify hy bulock mriifi.rnb) ULF/ELF Electromagnetic Fields VMD, VED, HED, HMD Submerged Dipoles Undersea /Air Communication...a whole, it appears that the vertical electric component produced by th HED in the plane of the dipole (• =0) should be the most useful for undersea

Predicting conditions for the reception of one-hop signals from the Siple transmitter experiment using the Kp index

NASA Astrophysics Data System (ADS)

Li, J. D.; Spasojevic, M.; Inan, U. S.

2015-10-01

Wave injection experiments provide an opportunity to explore and quantify aspects of nonlinear wave-particle phenomena in a controlled manner. Waves are injected into space from ground-based ELF/VLF transmitters, and the modified waves are measured by radio receivers on the ground in the conjugate hemisphere. These experiments are expensive and challenging projects to build and to operate, and the transmitted waves are not always detected in the conjugate region. Even the powerful transmitter located at Siple Station, Antarctica in 1986, estimated to radiate over 1 kW, only reported a reception rate of ˜40%, indicating that a significant number of transmissions served no observable scientific purpose and reflecting the difficulty in determining suitable conditions for transmission and reception. Leveraging modern machine-learning classification techniques, we apply two statistical techniques, a Bayes and a support vector machine classifier, to predict the occurrence of detectable one-hop transmissions from Siple data with accuracies on the order of 80%-90%. Applying these classifiers to our 1986 Siple data set, we detect 406 receptions of Siple transmissions which we analyze to generate more robust statistics on nonlinear growth rates, 3 dB/s-270 dB/s, and nonlinear total amplification, 3 dB-41 dB.

Semi-quantitative proteomics of mammalian cells upon short-term exposure to non-ionizing electromagnetic fields.

PubMed

Kuzniar, Arnold; Laffeber, Charlie; Eppink, Berina; Bezstarosti, Karel; Dekkers, Dick; Woelders, Henri; Zwamborn, A Peter M; Demmers, Jeroen; Lebbink, Joyce H G; Kanaar, Roland

2017-01-01

The potential effects of non-ionizing electromagnetic fields (EMFs), such as those emitted by power-lines (in extremely low frequency range), mobile cellular systems and wireless networking devices (in radio frequency range) on human health have been intensively researched and debated. However, how exposure to these EMFs may lead to biological changes underlying possible health effects is still unclear. To reveal EMF-induced molecular changes, unbiased experiments (without a priori focusing on specific biological processes) with sensitive readouts are required. We present the first proteome-wide semi-quantitative mass spectrometry analysis of human fibroblasts, osteosarcomas and mouse embryonic stem cells exposed to three types of non-ionizing EMFs (ELF 50 Hz, UMTS 2.1 GHz and WiFi 5.8 GHz). We performed controlled in vitro EMF exposures of metabolically labeled mammalian cells followed by reliable statistical analyses of differential protein- and pathway-level regulations using an array of established bioinformatics methods. Our results indicate that less than 1% of the quantitated human or mouse proteome responds to the EMFs by small changes in protein abundance. Further network-based analysis of the differentially regulated proteins did not detect significantly perturbed cellular processes or pathways in human and mouse cells in response to ELF, UMTS or WiFi exposure. In conclusion, our extensive bioinformatics analyses of semi-quantitative mass spectrometry data do not support the notion that the short-time exposures to non-ionizing EMFs have a consistent biologically significant bearing on mammalian cells in culture.

Examination of extremely low frequency electromagnetic fields on orthodontic tooth movement in rats

PubMed Central

Dogru, Mehmet; Akpolat, Veysi; Dogru, Arzum Guler; Karadede, Beyza; Akkurt, Atilim; Karadede, M. Irfan

2014-01-01

The purpose of this study was to evaluate whether 50 Hz extremely low frequency electromagnetic fields (ELF-EMFs) affect the amount of orthodontic tooth movement in rats. The experiments were performed on 18 male Sprague-Dawley rats. The rats were randomly divided into three groups (n = 6): cage-control (Cg-Cnt) group (n = 6); sinusoidal electromagnetic field (SEMF) group (n = 6); and pulsed electromagnetic field (PEMF) group (n = 6). In SEMF and PEMF groups, rats were subjected to 1.5 mT EMF exposure eight hours per day for eight days. In order to obtain tooth movement, holes were drilled on the right and left maxillary central incisors of the rats at a distance 1.5–2 mm away from the gingiva and 20 g of orthodontic forces were applied to the teeth. Generated linear model for repeated measures and Bonferroni tests were used to evaluate the differences between the groups. Interactions among groups by days were found by using Pillai's trace multivariate test. The results showed that significant differences were present among the groups (F = 5.035; p = 0.03) according to the extent of tooth movement. Significant differences between the amount of tooth movements were determined especially after the fifth day and the following days six, seven and eight (p < 0.001). Within the limitations, according to the results of the present study, the application of ELF-EMF accelerated the orthodontic tooth movement in rats. PMID:26019497

The transport of extremely low-frequency electrical signals through an acupuncture meridian compared to nonmeridian tissue.

PubMed

Spaulding, Keith; Chamberlin, Kent

2011-02-01

This study investigated the manner in which extremely low-frequency (ELF) electrical energy is transported through biologic tissues, focusing on the differences between an acupuncture meridian and nonmeridian tissues. Using inserted needles as the electrodes, the energy transport properties of the Large Intestine (LI) meridian were compared to a control channel that had the same length as the meridian channel and comprised similar soft tissue. Twenty (20) participants were tested at the University of New Hampshire, Durham, with ages ranging from 22 to 60 years old. A Gaussian pulse with spectral energy extending into the kilohertz range was launched using a low-impedance amplifier at the distal point on either the LI meridian or a nearby control channel. The signal launched was measured at the proximal point using a high-impedance instrumentation amplifier. The ground reference for both the launch and receiver locations was a needle inserted in the lower leg. After taking the Fast Fourier Transform, power spectral measurements were calculated, giving a single value representing power density of the measured potential in the 2-100-Hz range. A paired, two-sided signed rank test was performed. For the data pairs in this study, p = 0.035, indicating that they are dissimilar with a statistical significance. The ELF electric energy is transported somewhat more efficiently through the LI meridian compared to a nonmeridian control. The results were not dramatic, with some participants giving greater values on the control channel, but they were statistically significant.

Semi-quantitative proteomics of mammalian cells upon short-term exposure to non-ionizing electromagnetic fields

PubMed Central

Laffeber, Charlie; Eppink, Berina; Bezstarosti, Karel; Dekkers, Dick; Woelders, Henri; Zwamborn, A. Peter M.; Demmers, Jeroen; Lebbink, Joyce H. G.; Kanaar, Roland

2017-01-01

The potential effects of non-ionizing electromagnetic fields (EMFs), such as those emitted by power-lines (in extremely low frequency range), mobile cellular systems and wireless networking devices (in radio frequency range) on human health have been intensively researched and debated. However, how exposure to these EMFs may lead to biological changes underlying possible health effects is still unclear. To reveal EMF-induced molecular changes, unbiased experiments (without a priori focusing on specific biological processes) with sensitive readouts are required. We present the first proteome-wide semi-quantitative mass spectrometry analysis of human fibroblasts, osteosarcomas and mouse embryonic stem cells exposed to three types of non-ionizing EMFs (ELF 50 Hz, UMTS 2.1 GHz and WiFi 5.8 GHz). We performed controlled in vitro EMF exposures of metabolically labeled mammalian cells followed by reliable statistical analyses of differential protein- and pathway-level regulations using an array of established bioinformatics methods. Our results indicate that less than 1% of the quantitated human or mouse proteome responds to the EMFs by small changes in protein abundance. Further network-based analysis of the differentially regulated proteins did not detect significantly perturbed cellular processes or pathways in human and mouse cells in response to ELF, UMTS or WiFi exposure. In conclusion, our extensive bioinformatics analyses of semi-quantitative mass spectrometry data do not support the notion that the short-time exposures to non-ionizing EMFs have a consistent biologically significant bearing on mammalian cells in culture. PMID:28234898

Complex-Spectrum Magnetic Environment enhances and/or modifies Bioeffects of Hypokinetic Stress Condition: an Animal Study

NASA Astrophysics Data System (ADS)

Temuriantz, N. A.; Martinyuk, V. S.; Ptitsyna, N. G.; Villoresi, G.; Iucci, N.; Tyasto, M. I.; Dorman, L. I.

During last decades it was shown by many authors that ultra-low and extremely low frequency electric and magnetic fields ULF 0-10 Hz ELF 10-1000 Hz may produce biological effects and consequently may be a possible source for health problems Spaceflight electric and magnetic environments are characterized by complex combination of static and time-varying components in ULF-ELF range and by high variability The objective of this study was to investigate the possible influence of such magnetic fields on rats to understand the pathway regarding functional state of cardiovascular system Magnetic field MF pattern with variable complex spectra in 0-150 Hz frequency range was simulated using 3-axial Helmholtz coils and special computer-based equipment The effect of the real world MF exposure on rats was also tested in combination with hypokinetic stress condition which is typical for spaceflights It was revealed that variable complex-spectrum MF acts as a weak or moderate stress-like factor which amplifies and or modifies the functional shifts caused by other stress-factors The value and direction of the functional shifts caused by MF exposure significantly depend on gender individual-typological constitutional features and also on the physiological state norm stress of organism Our results support the idea that variable complex-spectrum MF action involves sympathetic activation overload in cholesterol transport in blood and also secretor activation of tissue basophyls mast cells that can influence the regional haemodynamics These

Cancer incidence and magnetic field exposure in industries using resistance welding in Sweden.

PubMed

Håkansson, N; Floderus, B; Gustavsson, P; Johansen, C; Olsen, J H

2002-07-01

To investigate cancer incidence in workers exposed to high levels of extremely low frequency magnetic fields (ELF-MF). A cohort based on the engineering industry was established. Industries assumed to use resistance welding in production were chosen in order to increase the prevalence of high exposed subjects and to reduce the influence of confounding factors. All men and women employed in these branches during 1985-94 were selected, 537 692 men and 180 529 women. Occupation, based on census information from 1980, 1985, and 1990, was linked to a job exposure matrix on ELF-MF. Four exposure groups were used by stratifying on mean workday ELF-MF exposure, using the lowest exposure group as reference. Cancer incidence was obtained by linkage to the Swedish Cancer Registry. Men in the very high exposure group showed an increased incidence of tumours of the kidney, pituitary gland, and biliary passages and liver; for these cancer sites an exposure-response relation was indicated. Women in the very high exposure group showed an increased incidence of astrocytoma I-IV, with a clear exposure-response pattern. An association was suggested in the high exposure group only, for cancer of the corpus uteri and multiple myeloma. Decreased risks in the very high exposure group among men were found for cancer of the colon and connective tissue/muscle. The results on cancer of the liver, kidney, and pituitary gland among men are in accordance with previous observations. Regarding brain tumours and leukaemia, the outcome for women provided further support of an association. The hypothesis of a biological mechanism involving the endocrine system was partly supported.

Modeling Long-Distance ELF Radio Atmospherics Generated by Rocket-Triggered Lightning

NASA Astrophysics Data System (ADS)

Moore, R. C.; Kunduri, B.; Anand, S.; Dupree, N.; Mitchell, M.; Agrawal, D.

2010-12-01

This paper addresses the generation and propagation of radio atmospherics (sferics) radiated by lightning in order to assess the ability to infer the electrical properties of lightning from great distances. This ability may prove to greatly enhance the understanding of lightning processes that are associated with the production of transient luminous events (TLEs) as well as other ionospheric effects associated with lightning. The modeling of the sferic waveform is carried out using a modified version of the Long Wavelength Propagation Capability (LWPC) code developed by the Naval Ocean Systems Center over a period of many years. LWPC is an inherently narrowband propagation code that has been modified to predict the broadband response of the Earth-ionosphere waveguide to an impulsive lightning flash. Unlike other similar efforts, the modified code presented preserves the ability of LWPC to account for waveguide mode-coupling and to account for changes to the electrical properties of the ground and ionosphere along the propagation path. The effort described is conducted in advance of the deployment of a global extremely low frequency (ELF) magnetic field array, which is presently under construction. The global ELF array is centered on the International Center for Lightning Research and Testing (ICLRT) located at Camp Blanding, Florida. The ICLRT is well-known for conducting rocket-triggered lightning experiments over the last 15-20 years. This paper uses lightning current waveforms directly measured at the base of the lightning channel (observations performed at the ICLRT) as an input to the model to predict the sferic waveform to be observed by the array under various ionospheric conditions. An analysis of the predicted sferic waveforms is presented, and the components of the lightning current waveform that most effectively excite the Earth-ionosphere waveguide are identified.

Effect of low frequency, low amplitude magnetic fields on the permeability of cationic liposomes entrapping carbonic anhydrase: II. No evidence for surface enzyme involvement.

PubMed

Ramundo-Orlando, A; Mattia, F; Palombo, A; D'Inzeo, G

2000-10-01

Observations recently reported by our group indicate that combined 7 Hz sinusoidal (B(acpeak) = 50 mu T) and parallel static (B(dc) = 50 mu T) magnetic fields can induce a significant increase in diffusion rate of substrate across carbonic anhydrase (CA)-loaded liposomes (DPPC:Chol:SA). A direct involvement of charges of stearylamine (SA) on the lipid membrane surface was also demonstrated. Kinetic studies showed that CA was mainly entrapped in liposomes at 5:3:2 molar ratio, although a small amount (17%) of enzyme was also located on the external surface of these cationic liposomes. In this paper we report steady state kinetic studies on this latter CA after ELF-EMFs exposure. No difference in the apparent K(m) between exposed and sham samples was observed. On the contrary the apparent V(max) was increased by approximately a factor of 2 after field exposure. In spite of the proteolytic digestion of this external CA, a significant increase of enzymatic activity, as a function of increase in the diffusion rate of substrate across the lipid bilayer, was observed in the exposed samples. Based on these results, a conformational change induced by the field on the CA located on the external surface of 5:3:2 liposomes is excluded as an explanation for our previous observations, supporting the primary role of bilayer SA in the interaction with ELF. A model of ELF interaction, based on the Larmor precession theory, explaining the physical phenomenon induced on the dipole of SA has been developed. Copyright 2000 Wiley-Liss, Inc.

Occupational exposures and Parkinson's disease mortality in a prospective Dutch cohort.

PubMed

Brouwer, Maartje; Koeman, Tom; van den Brandt, Piet A; Kromhout, Hans; Schouten, Leo J; Peters, Susan; Huss, Anke; Vermeulen, Roel

2015-06-01

We investigated the association between six occupational exposures (ie, pesticides, solvents, metals, diesel motor emissions (DME), extremely low frequency magnetic fields (ELF-MF) and electric shocks) and Parkinson's disease (PD) mortality in a large population-based prospective cohort study. The Netherlands Cohort Study on diet and cancer enrolled 58,279 men and 62,573 women aged 55-69 years in 1986. Participants were followed up for cause-specific mortality over 17.3 years, until December 2003, resulting in 402 male and 207 female PD deaths. Following a case-cohort design, a subcohort of 5,000 participants was randomly sampled from the complete cohort. Information on occupational history and potential confounders was collected at baseline. Job-exposure matrices were applied to assign occupational exposures. Associations with PD mortality were evaluated using Cox regression. Among men, elevated HRs were observed for exposure to pesticides (eg, ever high exposed, HR 1.27, 95% CI 0.86 to 1.88) and ever high exposed to ELF-MF (HR 1.54, 95% CI 1.00 to 2.36). No association with exposure duration or trend in cumulative exposure was observed for any of the occupational exposures. Results among women were unstable due to small numbers of high-exposed women. Associations with PD mortality were observed for occupational exposure to pesticides and ELF-MF. However, the weight given to these findings is limited by the absence of a monotonic trend with either duration or cumulative exposure. No associations were found between PD mortality and occupational exposure to solvents, metals, DME or electric shocks. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Pulsed Artificial Electrojet Generation

NASA Astrophysics Data System (ADS)

Papadopoulos, K.

2008-12-01

Traditional techniques for generating low frequency signals in the ULF/ELF range (.1-100 Hz) and rely on ground based Horizontal Electric Dipole (HED) antennas. It is, furthermore, well known that a Vertical Electric Dipole (VED) is by more than 50 dB more efficient than a HED with the same dipole current moment. However, the prohibitively long length of VED antennas in the ELF/ULF range coupled with voltage limitations due to corona discharge in the atmosphere make them totally impracticable. In this paper we discuss a novel concept, inspired by the physics of the equatorial electrojet, that allows for the conversion of a ground based HED to a VED in the E-region of the equatorial ionosphere with current moment comparable to the driving HED. The paper focuses in locations near the dip-equator, where the earth's magnetic is in predominantly in the horizontal direction. The horizontal electric field associated with a pulsed HED drives a large Hall current in the ionospheric E-region, resulting in a vertical current. It is shown that the pulsed vertical current in the altitude range 80-130 km, driven by a horizontal electric field of, approximately, .1 mV/m at 100 km altitude, is of the order of kA. This results in a pulsed VED larger than 106 A-m. Such a pulsed VED will drive ELF/ULF pulses with amplitude in excess of .1 nT at a lateral range larger than few hundred kilometers. This is by three orders of magnitude larger than the one expected by a HED with comparable current moment. The paper will conclude with the description of a sneak-through technique that allows for creating pulsed electric fields in the ionosphere much larger than expected from steady state oscillatory HED antennas.

Criticality safety evaluation for the Advanced Test Reactor enhanced low enriched uranium fuel elements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Montierth, Leland M.

2016-07-19

The Global Threat Reduction Initiative (GTRI) convert program is developing a high uranium density fuel based on a low enriched uranium (LEU) uranium-molybdenum alloy. Testing of prototypic GTRI fuel elements is necessary to demonstrate integrated fuel performance behavior and scale-up of fabrication techniques. GTRI Enhanced LEU Fuel (ELF) elements based on the ATR-Standard Size elements (all plates fueled) are to be fabricated for testing in the Advanced Test Reactor (ATR). While a specific ELF element design will eventually be provided for detailed analyses and in-core testing, this criticality safety evaluation (CSE) is intended to evaluate a hypothetical ELF element designmore » for criticality safety purposes. Existing criticality analyses have analyzed Standard (HEU) ATR elements from which controls have been derived. This CSE documents analysis that determines the reactivity of the hypothetical ELF fuel elements relative to HEU ATR elements and whether the existing HEU ATR element controls bound the ELF element. The initial calculations presented in this CSE analyzed the original ELF design, now referred to as Mod 0.1. In addition, as part of a fuel meat thickness optimization effort for reactor performance, other designs have been evaluated. As of early 2014 the most current conceptual designs are Mk1A and Mk1B, that were previously referred to as conceptual designs Mod 0.10 and Mod 0.11, respectively. Revision 1 evaluates the reactivity of the ATR HEU Mark IV elements for a comparison with the Mark VII elements.« less

Comparison of piperacillin exposure in the lungs of critically ill patients and healthy volunteers.

PubMed

Felton, T W; Ogungbenro, K; Boselli, E; Hope, W W; Rodvold, K A

2018-01-29

Severe infections of the respiratory tracts of critically ill patients are common and associated with excess morbidity and mortality. Piperacillin is commonly used to treat pulmonary infections in critically ill patients. Adequate antibiotic concentration in the epithelial lining fluid (ELF) of the lung is essential for successful treatment of pulmonary infection. To compare piperacillin pharmacokinetics/pharmacodynamics in the serum and ELF of healthy volunteers and critically ill patients. Piperacillin concentrations in the serum and ELF of healthy volunteers and critically ill patients were compared using population methodologies. Median piperacillin exposure was significantly higher in the serum and the ELF of critically ill patients compared with healthy volunteers. The IQR for serum piperacillin exposure in critically ill patients was six times greater than for healthy volunteers. The IQR for piperacillin exposure in the ELF of critically ill patients was four times greater than for healthy volunteers. The median pulmonary piperacillin penetration ratio was 0.31 in healthy volunteers and 0.54 in critically ill patients. Greater variability in serum and ELF piperacillin concentrations is observed in critically ill patients compared with healthy adult subjects and must be considered in the development of dosage regimens. Pulmonary penetration of antimicrobial agents should be studied in critically ill patients, as well as healthy volunteers, during drug development to ensure appropriate dosing of patients with pneumonia. © The Author(s) 2018. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Three-dimensional FDTD Modeling of Earth-ionosphere Cavity Resonances

NASA Astrophysics Data System (ADS)

Yang, H.; Pasko, V. P.

2003-12-01

Resonance properties of the earth-ionosphere cavity were first predicted by W. O. Schumann in 1952 [Schumann, Z. Naturforsch. A, 7, 149, 1952]. Since then observations of extremely low frequency (ELF) signals in the frequency range 1-500 Hz have become a powerful tool for monitoring of global lightning activity and planetary scale variability of the lower ionosphere, as well as, in recent years, for location and remote sensing of sprites, jets and elves and associated lightning discharges [e.g., Sato et al., JASTP, 65, 607, 2003; Su et al., Nature, 423, 974, 2003; and references cited therein]. The simplicity and flexibility of finite difference time domain (FDTD) technique for finding first principles solutions of electromagnetic problems in a medium with arbitrary inhomogeneities and ever-increasing computer power make FDTD an excellent candidate to be the technique of the future in development of realistic numerical models of VLF/ELF propagation in Earth-ionosphere waveguide [Cummer, IEEE Trans. Antennas Propagat., 48, 1420, 2000], and several reports about successful application of the FDTD technique for solution of related problems have recently appeared in the literature [e.g., Thevenot et al., Ann. Telecommun., 54, 297, 1999; Cummer, 2000; Berenger, Ann. Telecommun., 57, 1059, 2002, Simpson and Taflove, IEEE Antennas Wireless Propagat. Lett., 1, 53, 2002]. In this talk we will present results from a new three-dimensional spherical FDTD model, which is designed for studies of ELF electromagnetic signals under 100 Hz in the earth-ionosphere cavity. The model accounts for a realistic latitudinal and longitudinal variation of ground conductivity (i.e., for the boundaries between oceans and continents) by employing a broadband surface impedance technique proposed in [Breggs et al., IEEE Trans. Antenna Propagat., 41, 118, 1993]. The realistic distributions of atmospheric/lower ionospheric conductivity are derived from the international reference ionosphere model (IRI) [Bilitza, Radio Sci., 36, 261, 2001] and account for the medium anisotropy due to the geomagnetic field above approximately 70 km altitude. The realistic three-dimensional geomagnetic field distributions are loaded from the international geomagnetic field model (IGRF) [Barton, J. Geomag. Geoelectr., 49, 123, 1997]. In this talk we will compare the model results with available analytical solutions for electric and magnetic field distributions in the earth-ionosphere cavity excited by a strong positive cloud-to-ground lightning discharge. We will also discuss known sources of variability in Schumann resonance frequencies and present results illustrating model response under conditions of high-energy particle precipitation events in the polar regions [e.g., Morente et al., JGR, 108, doi:10.1029/2002JA009779, 2003, and references cited therein].

Initial Results of DC Electric Fields, Associated Plasma Drifts, Magnetic Fields, and Plasma Waves Observed on the C/NOFS Satellite

NASA Technical Reports Server (NTRS)

Pfaff, R.; Freudenreich, H.; Bromund, K.; Klenzing, J.; Rowland, D.; Maynard, N.

2010-01-01

Initial results are presented from the Vector Electric Field Investigation (VEFI) on the Air Force Communication/Navigation Outage Forecasting System (C/NOFS) satellite, a mission designed to understand, model, and forecast the presence of equatorial ionospheric irregularities. The VEFI instrument includes a vector DC electric field detector, a fixed-bias Langmuir probe operating in the ion saturation regime, a flux gate magnetometer, an optical lightning detector, and associated electronics including a burst memory. Compared to data obtained during more active solar conditions, the ambient DC electric fields and their associated E x B drifts are variable and somewhat weak, typically < 1 mV/m. Although average drift directions show similarities to those previously reported, eastward/outward during day and westward/downward at night, this pattern varies significantly with longitude and is not always present. Daytime vertical drifts near the magnetic equator are largest after sunrise, with smaller average velocities after noon. Little or no pre-reversal enhancement in the vertical drift near sunset is observed, attributable to the solar minimum conditions creating a much reduced neutral dynamo at the satellite altitude. The nighttime ionosphere is characterized by larger amplitude, structured electric fields, even where the plasma density appears nearly quiescent. Data from successive orbits reveal that the vertical drifts and plasma density are both clearly organized with longitude. The spread-F density depletions and corresponding electric fields that have been detected thus far have displayed a preponderance to appear between midnight and dawn. Associated with the narrow plasma depletions that are detected are broad spectra of electric field and plasma density irregularities for which a full vector set of measurements is available for detailed study. Finally, the data set includes a wide range of ELF/VLF/HF oscillations corresponding to a variety of plasma waves, in particular banded ELF hiss, whistlers, and lower hybrid wave turbulence triggered by lightning-induced sferics. The VEFI data represents a new set of measurements that are germane to numerous fundamental aspects of the electrodynamics and irregularities inherent to the Earth's low latitude ionosphere.

Analytic Theory of Titans Schumann Resonance: Constraints on Ionospheric Conductivity and Buried Water Ocean

NASA Technical Reports Server (NTRS)

Beghin, Christian; Randriamboarison, Orelien; Hamelin, Michel; Karkoschka, Erich; Sotin, Christophe; Whitten, Robert C.; Berthelier, Jean-Jacques; Grard, Rejean; Simoes, Fernando

2013-01-01

This study presents an approximate model for the atypical Schumann resonance in Titan's atmosphere that accounts for the observations of electromagnetic waves and the measurements of atmospheric conductivity performed with the Huygens Atmospheric Structure and Permittivity, Wave and Altimetry (HASI-PWA) instrumentation during the descent of the Huygens Probe through Titan's atmosphere in January 2005. After many years of thorough analyses of the collected data, several arguments enable us to claim that the Extremely Low Frequency (ELF) wave observed at around 36 Hz displays all the characteristics of the second harmonic of a Schumann resonance. On Earth, this phenomenon is well known to be triggered by lightning activity. Given the lack of evidence of any thunderstorm activity on Titan, we proposed in early works a model based on an alternative powering mechanism involving the electric current sheets induced in Titan's ionosphere by the Saturn's magnetospheric plasma flow. The present study is a further step in improving the initial model and corroborating our preliminary assessments. We first develop an analytic theory of the guided modes that appear to be the most suitable for sustaining Schumann resonances in Titan's atmosphere. We then introduce the characteristics of the Huygens electric field measurements in the equations, in order to constrain the physical parameters of the resonating cavity. The latter is assumed to be made of different structures distributed between an upper boundary, presumably made of a succession of thin ionized layers of stratospheric aerosols spread up to 150 km and a lower quasi-perfect conductive surface hidden beneath the non-conductive ground. The inner reflecting boundary is proposed to be a buried water-ammonia ocean lying at a likely depth of 55-80 km below a dielectric icy crust. Such estimate is found to comply with models suggesting that the internal heat could be transferred upwards by thermal conduction of the crust, while convective processes cannot be ruled out.

Early-life reproduction is associated with increased mortality risk but enhanced lifetime fitness in pre-industrial humans.

PubMed

Hayward, Adam D; Nenko, Ilona; Lummaa, Virpi

2015-04-07

The physiology of reproductive senescence in women is well understood, but the drivers of variation in senescence rates are less so. Evolutionary theory predicts that early-life investment in reproduction should be favoured by selection at the cost of reduced survival and faster reproductive senescence. We tested this hypothesis using data collected from preindustrial Finnish church records. Reproductive success increased up to age 25 and was relatively stable until a decline from age 41. Women with higher early-life fecundity (ELF; producing more children before age 25) subsequently had higher mortality risk, but high ELF was not associated with accelerated senescence in annual breeding success. However, women with higher ELF experienced faster senescence in offspring survival. Despite these apparent costs, ELF was under positive selection: individuals with higher ELF had higher lifetime reproductive success. These results are consistent with previous observations in both humans and wild vertebrates that more births and earlier onset of reproduction are associated with reduced survival, and with evolutionary theory predicting trade-offs between early reproduction and later-life survival. The results are particularly significant given recent increases in maternal ages in many societies and the potential consequences for offspring health and fitness. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

A single amino-acid substitution in the Ets domain alters core DNA binding specificity of Ets1 to that of the related transcription factors Elf1 and E74.

PubMed

Bosselut, R; Levin, J; Adjadj, E; Ghysdael, J

1993-11-11

Ets proteins form a family of sequence specific DNA binding proteins which bind DNA through a 85 aminoacids conserved domain, the Ets domain, whose sequence is unrelated to any other characterized DNA binding domain. Unlike all other known Ets proteins, which bind specific DNA sequences centered over either GGAA or GGAT core motifs, E74 and Elf1 selectively bind to GGAA corecontaining sites. Elf1 and E74 differ from other Ets proteins in three residues located in an otherwise highly conserved region of the Ets domain, referred to as conserved region III (CRIII). We show that a restricted selectivity for GGAA core-containing sites could be conferred to Ets1 upon changing a single lysine residue within CRIII to the threonine found in Elf1 and E74 at this position. Conversely, the reciprocal mutation in Elf1 confers to this protein the ability to bind to GGAT core containing EBS. This, together with the fact that mutation of two invariant arginine residues in CRIII abolishes DNA binding, indicates that CRIII plays a key role in Ets domain recognition of the GGAA/T core motif and lead us to discuss a model of Ets proteins--core motif interaction.

Early-life reproduction is associated with increased mortality risk but enhanced lifetime fitness in pre-industrial humans

PubMed Central

Hayward, Adam D.; Nenko, Ilona; Lummaa, Virpi

2015-01-01

The physiology of reproductive senescence in women is well understood, but the drivers of variation in senescence rates are less so. Evolutionary theory predicts that early-life investment in reproduction should be favoured by selection at the cost of reduced survival and faster reproductive senescence. We tested this hypothesis using data collected from preindustrial Finnish church records. Reproductive success increased up to age 25 and was relatively stable until a decline from age 41. Women with higher early-life fecundity (ELF; producing more children before age 25) subsequently had higher mortality risk, but high ELF was not associated with accelerated senescence in annual breeding success. However, women with higher ELF experienced faster senescence in offspring survival. Despite these apparent costs, ELF was under positive selection: individuals with higher ELF had higher lifetime reproductive success. These results are consistent with previous observations in both humans and wild vertebrates that more births and earlier onset of reproduction are associated with reduced survival, and with evolutionary theory predicting trade-offs between early reproduction and later-life survival. The results are particularly significant given recent increases in maternal ages in many societies and the potential consequences for offspring health and fitness. PMID:25740893

Compilation of 1985 Annual Reports of the Navy ELF (Extremely Low Frequency) Communications System Ecological Monitoring Program. Volume 1. Tabs A-C.

DTIC Science & Technology

1986-07-01

and straight when short, but spindly and often crooked when long, ususally somewhat constricted at the base. Microscopic -- Surface hyphae sparse, 2-3... hyphae with conspicuous interlocking, "jig-saw puzzle-like" pattern; cortical cells red-brown except over apex where they are colorless; Hartig net hyphae ...Type S Macroscopic -- Black, sometimes with lighter apex; usually fuzzy, with abundant attached, coarse hyphae ; 1-3 mm long X 0.5-1.0 mm diameter; mono

Growth and Development of Rhesus Monkeys Exposed to ELF (Extremely Low Frequency) Electric and Magnetic Fields during the First 54 Months of Life.

DTIC Science & Technology

1986-05-01

measurements were of an anatomical region rather than a specific bone. Measurements were made of head width, head length, shoulder width, hip width...the4 elbows behind its back. It was also necessary to palpate the bone to be sure that the measuring points were over the bony surface and not on the...11Z surrounding musculature. Hip width was measured with the ends of the open calipers on the two points of the greater trochanter. It was observed

Compilation of 1987 Annual Reports of the Navy ELF (Extremely Low Frequency) Communications System Ecological Monitoring Program. Volume 3

DTIC Science & Technology

1988-08-01

particles on substrates in its absence. The pumps were powered by a heavy duty, marine 12 volt battery, which had to be exchanged and recharged daily. Two of...lowland stream (Costa Rica, Central America). Brenesia, 14:1-11. Stout, R. J., 1981. How abiotic factors affect the distri- bution of two species of...increment, and an examination of the effect of population size using CPUE and abiotic factors on growth. ,These analyses should allow us to separate the

Compilation of 1985 Annual Reports of the Navy ELF (Extremely Low Frequency) Communications System Ecological Monitoring Program. Volume 3. Tabs H-J.

DTIC Science & Technology

1986-07-01

Stout, R. J., 1981. How abiotic factors affect the distri- bution of two species of tropical predaceous aquatic bugs. Ecology, 62:1170-1178. 105 Element...pumps were powered by a heavy duty marine battery which had to be exchanged and recharged daily. Two of these streams were constructed so that identical...integrate the habitats used by fish, fish-invertebrate interactions, and abiotic factors. The specific objectives are: 1) To establish a taxonomic base of

Plasma Antenna Based on Superparamagnetic Nanoparticles

NASA Astrophysics Data System (ADS)

Papadopoulos, K.

2017-12-01

A novel plasma antenna for space or ground based generation and injection of whistler and Alfven waves is presented. The new antenna concept is based on recently manufactured, small (10-60 nm radius), single domain, non-interacting magnetic grains with uniaxial magnetic anisotropy, known as superparamagnetic nanoparticles (SPN), dispersed in low viscosity, non-conducting media. SPNs can be described as ensembles of non-interacting magnetic moments μ with energy E=-μB when driven by a magnetic field B, similar to ordinary paramagnets, with exception that SPNs are composed by many thousands of magnetic atoms and as result have susceptibilities comparable to ferromagnets but with zero coercivity. The Langevin function accurately describes the dynamic behavior of the magnetization in the presence of low frequency AC fields since the characteristic mechanical (Brownian) and magnetic (Neel) relaxation times are shorter than 10msecs. For ground-based applications the grains are suspended in low viscosity carrier liquids, such as water or benzne and are known as ferrofluids. For space based applications, such as wave injection from CubeSats they can be dispersed as dust in vacuum containers. Agglomeration is avoided by coating the grains by coating their surface by an appropriate surfactant molecule. The ensemble of magnetic grains is driven to rotation at the desired VLF or ELF frequency by a pair of Helmholtz like coils surrounding the grain container. The near field electric field associated with rotating magnetic field then drives currents such as were observed in Rotating Magnetic Field experiments at the UCLA/LAPD chamber [Gigliotti et al., Phys. of Plasmas 16:092106; Karavaev et al., Phys. of Plasmas 17(1):012102,2010]. The magnetic moment of the AC coil is amplified by the susceptibility χ of the SPN ensemble that depending on the grain size and material can reach values of 104-105. Preliminary estimates indicate that less than 1 kg of SPN grains and power of the order of 10 W can inject in the radiation belts EMIC and whistler waves with amplitude more than 100 pT and controlled chirp. Acknowledgments: This research is supported by AFOSR grant F9550-13-1-0194. Contributions from Drs. T. Wallace, C. L. Chang, I. Smolyaninov, V. Smolyaninova, M. Sanjini, and Profs I. Meyergoyz and C. Davis are gratefully acknowledged.

Loss of Elongation-Like Factor 1 Spontaneously Induces Diverse, RNase H-Related Suppressor Mutations in Schizosaccharomyces pombe.

PubMed

Marayati, Bahjat F; Drayton, Alena L; Tucker, James F; Huckabee, Reid H; Anderson, Alicia M; Pease, James B; Zeyl, Clifford W; Zhang, Ke

2018-05-29

A healthy individual may carry a detrimental genetic trait that is masked by another genetic mutation. Such suppressive genetic interactions, in which a mutant allele either partially or completely restores the fitness defect of a particular mutant, tend to occur between genes that have a confined functional connection. Here we investigate a self-recovery phenotype in Schizosaccharomyces pombe , mediated by suppressive genetic interactions that can be amplified during cell culture. Cells without Elf1, an AAA+ family ATPase, have severe growth defects initially, but quickly recover growth rates near to those of wild-type strains by acquiring suppressor mutations. elf1Δ cells accumulate RNAs within the nucleus and display effects of genome instability such as sensitivity to DNA damage, increased incidence of lagging chromosomes, and mini-chromosome loss. Notably, the rate of phenotypic recovery was further enhanced in elf1Δ cells when RNase H activities were abolished and significantly reduced upon overexpression of RNase H1, suggesting that loss of Elf1-related genome instability can be resolved by RNase H activities, likely through eliminating the potentially mutagenic DNA-RNA hybrids caused by RNA nuclear accumulation. Using whole genome sequencing, we mapped a few consistent suppressors of elf1Δ including mutated Cue2, Rpl2702, and SPBPJ4664.02, suggesting previously unknown functional connections between Elf1 and these proteins. Our findings describe a mechanism by which cells bearing mutations that cause fitness defects and genome instability may accelerate the fitness recovery of their population through quickly acquiring suppressors. We propose that this mechanism may be universally applicable to all microorganisms in large-population cultures. Copyright © 2018, Genetics.

Conservation and Divergence of Circadian Clock Operation in a Stress-Inducible Crassulacean Acid Metabolism Species Reveals Clock Compensation against Stress1

PubMed Central

Boxall, Susanna F.; Foster, Jonathan M.; Bohnert, Hans J.; Cushman, John C.; Nimmo, Hugh G.; Hartwell, James

2005-01-01

One of the best-characterized physiological rhythms in plants is the circadian rhythm of CO2 metabolism in Crassulacean acid metabolism (CAM) plants, which is the focus here. The central components of the plant circadian clock have been studied in detail only in Arabidopsis (Arabidopsis thaliana). Full-length cDNAs have been obtained encoding orthologs of CIRCADIAN CLOCK-ASSOCIATED1 (CCA1)/LATE ELONGATED HYPOCOTYL (LHY), TIMING OF CAB EXPRESSION1 (TOC1), EARLY FLOWERING4 (ELF4), ZEITLUPE (ZTL), FLAVIN-BINDING KELCH REPEAT F-BOX1 (FKF1), EARLY FLOWERING3 (ELF3), and a partial cDNA encoding GIGANTEA in the model stress-inducible CAM plant, Mesembryanthemum crystallinum (Common Ice Plant). TOC1 and LHY/CCA1 are under reciprocal circadian control in a manner similar to their regulation in Arabidopsis. ELF4, FKF1, ZTL, GIGANTEA, and ELF3 are under circadian control in C3 and CAM leaves. ELF4 transcripts peak in the evening and are unaffected by CAM induction. FKF1 shows an abrupt transcript peak 3 h before subjective dusk. ELF3 transcripts appear in the evening, consistent with their role in gating light input to the circadian clock. Intriguingly, ZTL transcripts do not oscillate in Arabidopsis, but do in M. crystallinum. The transcript abundance of the clock-associated genes in M. crystallinum is largely unaffected by development and salt stress, revealing compensation of the central circadian clock against development and abiotic stress in addition to the well-known temperature compensation. Importantly, the clock in M. crystallinum is very similar to that in Arabidopsis, indicating that such a clock could control CAM without requiring additional components of the central oscillator or a novel CAM oscillator. PMID:15734916

Using the Evaluative Linguistic Framework for Questionnaires to Assess Comprehensibility of Self-Report Health Questionnaires.

PubMed

Clerehan, Rosemary; Guillemin, Francis; Epstein, Jonathan; Buchbinder, Rachelle

2016-06-01

The Evaluative Linguistic Framework (ELF) was developed to judge the quality of health care texts for patients, based on systemic functional linguistic theory. This approach considers key variables such as context and structure, known to be important for communication. Our objective was to adapt the ELF to evaluate the quality of self-report questionnaires. We reviewed the Health Literacy Questionnaire using the ELF. On the basis of these data, we drafted the preliminary version of the Evaluative Linguistic Framework for Questionnaires (ELF-Q) and applied it to English- and French-language versions of two arthritis self-report questionnaires and to Spanish, Dutch, and Turkish versions of an arthritis questionnaire. The developed ELF-Q was found to be effective for evaluating questionnaires in English and in four other languages. It contains nine items with new descriptions and assessment probes. These include overall organizational or generic structure of the questionnaire, metadiscourse (or text about the text), headings, rhetorical elements (function of each "move" or stage of the text in relation to the reader), the writer-reader relationship, technicality of vocabulary, lexical density (proportion of content words in the text), format, and overall judgment. We added assessment responses on a two- or three-point Likert scale to complement the assessment probes and make the intent and meaning of the probes fully explicit for the questionnaire developer or assessor. The ELF-Q is a framework practical to use for the development or assessment of any type of self-report questionnaire. Its application can identify features of a self-report questionnaire that could be improved to optimize its comprehensibility. Copyright © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

THE DEVELOPMENT OF A SINGLE-CELL FIELD DIAGNOSTIC FOR NITROGEN LIMITATION IN HARMFUL ALGAE

EPA Science Inventory

This project proposes the development of an assay to identify cell-specific acetylglucosaminidase activity using the substrate ELF-NAG (ELF 97 N'-acetylglucosaminide). Preliminary data indicates this enzyme is nitrogen-regulated in Alexandrium and that this ass...

[Papers of the ELF Project].

ERIC Educational Resources Information Center

Barker, Philip; And Others

The five papers in this collection discuss various aspects of the Electronic Learning-Package Factory (ELF) project at the University of Bradford in England. In the first paper, "Adoption of CAL in Higher Education: A Cooperative Approach to Research, Development and Implementation," Philip Barker considers the opportunities for…

Analysis of ELF Radio Atmospherics Radiated by Rocket-Triggered Lightning

NASA Astrophysics Data System (ADS)

Dupree, N. A.; Moore, R. C.; Pilkey, J. T.; Uman, M. A.; Jordan, D. M.; Caicedo, J. A.; Hare, B.; Ngin, T. K.

2014-12-01

Experimental observations of ELF radio atmospherics produced by rocket-triggered lightning flashes are used to analyze Earth-ionosphere waveguide excitation and propagation characteristics. Rocket-triggered lightning experiments are performed at the International Center for Lightning Research and Testing (ICLRT) located at Camp Blanding, Florida. Long-distance ELF observations are performed in California, Greenland, and Antarctica. The lightning current waveforms directly measured at the base of the lightning channel (at the ICLRT) along with pertinent Lightning Mapping Array (LMA) data are used together with the Long Wavelength Propagation Capability (LWPC) code to predict the radio atmospheric (sferic) waveform observed at the receiver locations under various ionospheric conditions. We identify fitted exponential electron density profiles that accurately describe the observed propagation delays, phase delays, and signal amplitudes. The ability to infer ionospheric characteristics using distant ELF observations greatly enhances ionospheric remote sensing capabilities, especially in regard to interpreting observations of transient luminous events (TLEs) and other ionospheric effects associated with lightning.

ALTERATIONS IN CALCIUM ION ACTIVITY BY ELF AND RF ELECTROMAGNETIC FIELDS

EPA Science Inventory

Alterations in calcium ion activity by ELF and RF electromagnetic fields

Introduction

Calcium ions play many important roles in biological systems. For example, calcium ion activity can be used as an indicator of second-messenger signal-transduction processe...

Verification of a Schumann Resonance Inversion Method for Global Lightning Activity in Absolute Units

NASA Astrophysics Data System (ADS)

Williams, E. R.; Guha, A.; Liu, Y.; Boldi, R. A.; Pracser, E.; Said, R.; Satori, G.; Bozoki, T.; Bor, J.; Atkinson, M.; Beggan, C.; Cummer, S.; Lyu, F.; Fain, B.; Hobara, Y.; Alexander, K.; Kulak, A.; McCraty, R.; Mlynarczyk, J.; Montanya, J.; Moore, R. C.; Neska, M.; Ortega, P.; Price, C. G.; Rawat, R.; Sato, M.; Sinha, A. K.; Yampolski, Y.

2017-12-01

The global reach of single, calibrated ELF receivers operating in the Schumann resonance (SR) band (3-50 Hz) has been verified by global maps of energetic Q-burst locations and vertical charge moment change, and by locations of independently verified transient luminous events in a wide variety of locations worldwide. It has also been previously shown that with as few as six ELF receivers in widely separated locations, multi-station, multi-modal SR parameters extracted from the SR "background" signal can be inverted to provide the centroid locations of continental lightning "chimneys" (Asia, Africa, Americas) and their respective lightning activities in absolute units (coul2 km2/sec). This inversion method involves a propagation model for the Earth-ionosphere cavity with day-night asymmetry. The Earth is now populated with more than 30 calibrated ELF receivers making continuous time series observations. This circumstance is exploited in the present study to verify the findings of the ELF inversion method. During the period May 17-20 and 23-24, 2015, two independent sets of nine ELF receivers each, in widely-separated geographical locations (first set: Antarctica (3 sites), Hungary, Japan (2 sites), Poland, Spitzbergen, and USA; second set: Antarctica, Canada, Cape Verde Island, Lithuania, New Zealand, Saudi Arabia, Scotland, Tahiti, and USA), are used to compare the locations and source strengths of lightning chimneys. Detailed comparisons will be shown over Universal Time for selected days.

Weak extremely-low-frequency magnetic fields and regeneration in the planarian Dugesia tigrina

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jenrow, K.A.; Smith, C.H.; Liboff, A.R.

1995-06-01

Extremely-low-frequency (ELF), low-intensity magnetic fields have been shown to influence cell signaling processes in a variety of systems, both in vivo and in vitro. Similar effects have been demonstrated for nervous system development and neurite outgrowth. The authors report that regeneration in planaria, which incorporates many of these processes, is also affected by ELF magnetic fields. The rate of cephalic regeneration, reflected by the mean regeneration time (MRT), for planaria populations regenerating under continuous exposure to combined DC (78.4 {mu}T) and AC (60.0 Hz at 10.0 {mu}T{sub peak}) magnetic fields applied in parallel was found to be significantly delayed (Pmore » {much_lt} 0.001) by 48 {+-} 1 h relative to two different types of control populations (MRT {minus}140 {+-} 12 h). One control population was exposed to only the AC component of this field combination, while the other experienced only the ambient geomagnetic field. All measurements were conducted in a low-gradient, low-noise magnetics laboratory under well-maintained temperature conditions. This delay in regeneration was shown to be dependent on the planaria having a fixed orientation with respect to the magnetic field vectors. Results also indicate that this orientation-dependent transduction process does not result from Faraday induction but is consistent with a Ca{sup 2+} cyclotron resonance mechanism. Data interpretation also permits the tentative conclusion that the effect results from an inhibition of events at an early stage in the regeneration process before the onset of proliferation and differentiation.« less

Conflict or Cooperation: The Use of Backchannelling in ELF Negotiations

ERIC Educational Resources Information Center

Bjorge, Anne Kari

2010-01-01

The international business community relies heavily on English Lingua Franca (ELF) as a shared means of communication, and English business language programmes thus feature prominently within the field of English for Specific Purposes (ESP). Business ESP programmes, however, have little focus on active listening, which previous research has…

Ambient temperature response establishes ELF3 as a required component of the Arabidopsis core circadian clock

USDA-ARS?s Scientific Manuscript database

Circadian clocks synchronize internal processes with environmental cycles to ensure optimal timing of biological events on daily and seasonal timescales. External light and temperature cues set the core molecular oscillator to local conditions. In Arabidopsis, EARLY FLOWERING 3 (ELF3) is thought to ...

Magnetic correlates in electromagnetic consciousness.

PubMed

Liboff, A R

2016-01-01

We examine the hypothesis that consciousness is a manifestation of the electromagnetic field, finding supportive factors not previously considered. It is not likely that traditional electrophysiological signaling modes can be readily transmitted throughout the brain to properly enable this field because of electric field screening arising from the ubiquitous distribution of high dielectric lipid membranes, a problem that vanishes for low-frequency magnetic fields. Many reports over the last few decades have provided evidence that living tissue is robustly sensitive to ultrasmall (1-100 nT) ELF magnetic fields overlapping the γ-frequency range often associated with awareness. An example taken from animal behavior (coherent bird flocking) lends support to the possibility of a disembodied electromagnetic consciousness. In contrast to quantum consciousness hypotheses, the present approach is open to experimental trial.

Is There ELF in ELT Coursebooks?

ERIC Educational Resources Information Center

Vettorel, Paola; Lopriore, Lucilla

2013-01-01

This article aims to explore whether well-attested findings in the fields of World Englishes (WE) and of English as a lingua franca (ELF) have determined a shift in perspective in the overall approach to English language teaching (ELT), and how far this shift has permeated teaching materials and coursebooks. The research study was carried out in…

English as a Lingua Franca in Europe: Bilingualism and Multicompetence

ERIC Educational Resources Information Center

MacKenzie, Ian

2012-01-01

Many multilinguals in Europe habitually use the linguistic strategies often attributed to users of English as a lingua franca (ELF). ELF, in which native speaker norms are not invoked, may be the perfect arena for multilinguals to exploit what Vivian Cook calls "multicompetence", a dynamic multilingual system in which more than one…

Enhanced Low-Enriched Uranium Fuel Element for the Advanced Test Reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pope, M. A.; DeHart, M. D.; Morrell, S. R.

2015-03-01

Under the current US Department of Energy (DOE) policy and planning scenario, the Advanced Test Reactor (ATR) and its associated critical facility (ATRC) will be reconfigured to operate on low-enriched uranium (LEU) fuel. This effort has produced a conceptual design for an Enhanced LEU Fuel (ELF) element. This fuel features monolithic U-10Mo fuel foils and aluminum cladding separated by a thin zirconium barrier. As with previous iterations of the ELF design, radial power peaking is managed using different U-10Mo foil thicknesses in different plates of the element. The lead fuel element design, ELF Mk1A, features only three fuel meat thicknesses,more » a reduction from the previous iterations meant to simplify manufacturing. Evaluation of the ELF Mk1A fuel design against reactor performance requirements is ongoing, as are investigations of the impact of manufacturing uncertainty on safety margins. The element design has been evaluated in what are expected to be the most demanding design basis accident scenarios and has met all initial thermal-hydraulic criteria.« less

Toward the Prediction of Water Exchange Rates in Magnetic Resonance Imaging Contrast Agents: A Density Functional Theory Study.

PubMed

Regueiro-Figueroa, Martín; Platas-Iglesias, Carlos

2015-06-18

We present a theoretical investigation of Gd-Owater bonds in different complexes relevant as contrast agents in magnetic resonance imaging (MRI). The analysis of the Ln-Owater distances, electron density (ρBCP), and electron localization function (ELF) at the bond critical points of [Ln(DOTA)(H2O)](-) and [Ln(DTPA-BMA)(H2O)] indicates that the strength of the Ln-Owater bonds follows the order DTPA-BMA > DOTA (M isomer) > DOTA (m isomer). The ELF values decrease along the 4f period as the Ln-Owater bonds get shorter, in line with the labile capping bond phenomenon. Extension of these calculations to other Gd(3+) complexes allowed us to correlate the experimentally observed water exchange rates and the calculated ρBCP and ELF values. The water exchange reaction becomes faster as the Gd-Owater bonds are weakened, which is reflected in longer bond distances and lower values of ρBCP and ELF. DKH2 calculations show that the two coordinated water molecules may also have significantly different (17)O hyperfine coupling constants (HFCCs).

The European Lead Factory: A Blueprint for Public-Private Partnerships in Early Drug Discovery.

PubMed

Karawajczyk, Anna; Orrling, Kristina M; de Vlieger, Jon S B; Rijnders, Ton; Tzalis, Dimitrios

2016-01-01

The European Lead Factory (ELF) is a public-private partnership (PPP) that provides researchers in Europe with a unique platform for translation of innovative biology and chemistry into high-quality starting points for drug discovery. It combines an exceptional collection of small molecules, high-throughput screening (HTS) infrastructure, and hit follow-up capabilities to advance research projects from both private companies and publicly funded researchers. By active interactions with the wider European life science community, ELF connects and unites bright ideas, talent, and experience from several disciplines. As a result, ELF is a unique, collaborative lead generation engine that has so far resulted in >4,500 hit compounds with a defined biological activity from 83 successfully completed HTS and hit evaluation campaigns. The PPP has also produced more than 120,000 novel innovative library compounds that complement the 327,000 compounds contributed by the participating pharmaceutical companies. Intrinsic to its setup, ELF enables breakthroughs in areas with unmet medical and societal needs, where no individual entity would be able to create a comparable impact in such a short time.

The European Lead Factory: A Blueprint for Public–Private Partnerships in Early Drug Discovery

PubMed Central

Karawajczyk, Anna; Orrling, Kristina M.; de Vlieger, Jon S. B.; Rijnders, Ton; Tzalis, Dimitrios

2017-01-01

The European Lead Factory (ELF) is a public–private partnership (PPP) that provides researchers in Europe with a unique platform for translation of innovative biology and chemistry into high-quality starting points for drug discovery. It combines an exceptional collection of small molecules, high-throughput screening (HTS) infrastructure, and hit follow-up capabilities to advance research projects from both private companies and publicly funded researchers. By active interactions with the wider European life science community, ELF connects and unites bright ideas, talent, and experience from several disciplines. As a result, ELF is a unique, collaborative lead generation engine that has so far resulted in >4,500 hit compounds with a defined biological activity from 83 successfully completed HTS and hit evaluation campaigns. The PPP has also produced more than 120,000 novel innovative library compounds that complement the 327,000 compounds contributed by the participating pharmaceutical companies. Intrinsic to its setup, ELF enables breakthroughs in areas with unmet medical and societal needs, where no individual entity would be able to create a comparable impact in such a short time. PMID:28154815

Extremely Low Frequency (ELF) Communication System. Ecological Monitoring Program: Wisconsin Bird Studies

DTIC Science & Technology

1991-02-01

Passerina cyanea Chipping Sparrow 15 12 10 1 19 4 25 3 69 20 3 Spizella passerina Lark Sparrow 0 0 0 0 4 0 3 0 7 0 3...27 2 1 Passerina cyanea Chipping Sparrow 9 2 3 6 8 0 7 0 27 8 Spizella passerina Lark Sparrow 0 0 2 0 0 0 0 0 2 0 Chondestes prammacus Song Sparrow 19...Chipping Sparrow 1 0 0 0 0 1 0 0 1 1 Spizella passerina I Song Sparrow 3 1 9 1 4 0 9 1 25 3 Melospiza melodia I Swamp Sparrow 6

Compilation of 1984 Annual Reports of the Navy ELF (Extremely Low Frequency) Communications System Ecological Monitoring Program. Volume 1. TABS A-E.

DTIC Science & Technology

1985-06-01

parviforus 4.0 Trientalis borealis --- 7.9 Vaccinium membranaceum 4.2 3.3 Viburnum acerfolium --- 11.1 Waldsteinia fragaria --- 1.6 I ". r h m li mm...Templeton) Pseudachorutes spp. complex Isotoridae: Isotoma (Tesoria) nigrifrons Folsom 1. (Isotona) viridis Bourlet * FEntomobryidae: Tomocerus...67.1 66.4 66.9 71.9 Z 0. hexfasciata 16.4 13.2 17.6 14.2 N Isotomidae 50 36 84 67 % I. niarifrons 50.0 55.6 57.1 76.1 %I. viridis 50.0 44.4 42.9 23.9 N

Enhanced liver fibrosis test using ELISA assay accurately discriminates advanced stage of liver fibrosis as determined by transient elastography fibroscan in treatment naïve chronic HCV patients.

PubMed

Omran, Dalia; Yosry, Ayman; Darweesh, Samar K; Nabeel, Mohammed M; El-Beshlawey, Mohammed; Saif, Sameh; Fared, Azza; Hassany, Mohamed; Zayed, Rania A

2018-02-01

Evaluation of liver fibrosis stage is crucial in the assessment of chronic HCV patients, regarding decision to start treatment and during follow-up. Our aim was to assess the validity of the enhanced liver fibrosis (ELF) score in discrimination of advanced stage of liver fibrosis in naïve chronic HCV patients. We prospectively evaluated liver fibrosis stage in one hundred eighty-one naïve chronic HCV Egyptian patients by transient elastography (TE)-FibroScan. Patients were categorized into mild to moderate fibrosis (≤F2) group and advanced fibrosis (≥F3) group. The ELF score components, hyaluronic acid (HA), amino-terminal propeptide of type-III-procollagen (PIIINP) and tissue inhibitor of metalloproteinase type-1 (TIMP-1), were done using ELISA test. The mean values of ELF and its individual components significantly correlated with the hepatic fibrosis stage as measured by TE-FibroScan (P value 0.001). ELF cutoff value of 9.8 generated a sensitivity of 77.8%, specificity of 67.1%, area under the receiver operator characteristic curve (AUROC) of 0.76 with 95% confidence interval [CI] (0.68-0.83) for detecting advanced fibrosis (F ≥ 3). ELF panel is a good, reliable noninvasive test and showed comparable results to TE-FibroScan in detecting liver fibrosis stage in treatment naïve chronic HCV patients.

A role for CFTR in the elevation of glutathione levels in the lung by oral glutathione administration

PubMed Central

Kariya, Chirag; Leitner, Heather; Min, Elysia; van Heeckeren, Christiaan; van Heeckeren, Anna; Day, Brian J.

2014-01-01

The cystic fibrosis transmembrane conductance regulator (CFTR) protein is the only known apical glutathione (GSH) transporter in the lung. The purpose of these studies was to determine whether oral GSH or glutathione disulfide (GSSG) treatment could increase lung epithelial lining fluid (ELF) GSH levels and whether CFTR plays a role in this process. The pharmacokinetic profile of an oral bolus dose of GSH (300 mg/kg) was determined in mice. Plasma, ELF, bronchoalveolar lavage (BAL) cells, and lung tissue were analyzed for GSH content. There was a rapid elevation in the GSH levels that peaked at 30 min in the plasma and 60 min in the lung, ELF, and BAL cells after oral GSH dosing. Oral GSH treatment produced a selective increase in the reduced and active form of GSH in all lung compartments examined. Oral GSSG treatment (300 mg/kg) resulted in a smaller increase of GSH levels. To evaluate the role of CFTR in this process, Cftr knockout (KO) mice and gut-corrected Cftr KO-transgenic (Tg) mice were given an oral bolus dose of GSH (300 mg/kg) and compared with wild-type mice for changes in GSH levels in plasma, lung, ELF, and BAL cells. There was a twofold increase in plasma, a twofold increase in lung, a fivefold increase in ELF, and a threefold increase in BAL cell GSH levels at 60 min in wild-type mice; however, GSH levels only increased by 40% in the plasma, 60% in the lung, 50% in the ELF, and twofold in the BAL cells within the gut-corrected Cftr KO-Tg mice. No change in GSH levels was observed in the uncorrected Cftr KO mice. These studies suggest that CFTR plays an important role in GSH uptake from the diet and transport processes in the lung. PMID:17369290

Comparison of Omadacycline and Tigecycline Pharmacokinetics in the Plasma, Epithelial Lining Fluid, and Alveolar Cells of Healthy Adult Subjects.

PubMed

Gotfried, Mark H; Horn, Karolyn; Garrity-Ryan, Lynne; Villano, Stephen; Tzanis, Evan; Chitra, Surya; Manley, Amy; Tanaka, S Ken; Rodvold, Keith A

2017-09-01

The steady-state concentrations of omadacycline and tigecycline in the plasma, epithelial lining fluid (ELF), and alveolar cells (AC) of 58 healthy adult subjects were obtained. Subjects were administered either omadacycline at 100 mg intravenously (i.v.) every 12 h for two doses followed by 100 mg i.v. every 24 h for three doses or tigecycline at an initial dose of 100 mg i.v. followed by 50 mg i.v. every 12 h for six doses. A bronchoscopy and bronchoalveolar lavage were performed once in each subject following the start of the fifth dose of omadacycline at 0.5, 1, 2, 4, 8, 12, or 24 h and after the start of the seventh dose of tigecycline at 2, 4, 6, or 12 h. The value of the area under the concentration-time curve (AUC) from time zero to 24 h postdosing (AUC 0-24 ) (based on mean concentrations) in ELF and the ratio of the ELF to total plasma omadacycline concentration based on AUC 0-24 values were 17.23 mg · h/liter and 1.47, respectively. The AUC 0-24 value in AC was 302.46 mg · h/liter, and the ratio of the AC to total plasma omadacycline concentration was 25.8. In comparison, the values of the AUC from time zero to 12 h postdosing (AUC 0-12 ) based on the mean concentrations of tigecycline in ELF and AC were 3.16 and 38.50 mg · h/liter, respectively. The ratio of the ELF and AC to total plasma concentrations of tigecycline based on AUC 0-12 values were 1.71 and 20.8, respectively. The pharmacokinetic advantages of higher and sustained concentrations of omadacycline compared to those of tigecycline in plasma, ELF, and AC suggest that omadacycline is a promising antibacterial agent for the treatment of lower respiratory tract bacterial infections caused by susceptible pathogens. Copyright © 2017 Gotfried et al.

Characterisation of exposure to non-ionising electromagnetic fields in the Spanish INMA birth cohort: study protocol.

PubMed

Gallastegi, Mara; Guxens, Mònica; Jiménez-Zabala, Ana; Calvente, Irene; Fernández, Marta; Birks, Laura; Struchen, Benjamin; Vrijheid, Martine; Estarlich, Marisa; Fernández, Mariana F; Torrent, Maties; Ballester, Ferrán; Aurrekoetxea, Juan J; Ibarluzea, Jesús; Guerra, David; González, Julián; Röösli, Martin; Santa-Marina, Loreto

2016-02-18

Analysis of the association between exposure to electromagnetic fields of non-ionising radiation (EMF-NIR) and health in children and adolescents is hindered by the limited availability of data, mainly due to the difficulties on the exposure assessment. This study protocol describes the methodologies used for characterising exposure of children to EMF-NIR in the INMA (INfancia y Medio Ambiente- Environment and Childhood) Project, a prospective cohort study. Indirect (proximity to emission sources, questionnaires on sources use and geospatial propagation models) and direct methods (spot and fixed longer-term measurements and personal measurements) were conducted in order to assess exposure levels of study participants aged between 7 and 18 years old. The methodology used varies depending on the frequency of the EMF-NIR and the environment (homes, schools and parks). Questionnaires assessed the use of sources contributing both to Extremely Low Frequency (ELF) and Radiofrequency (RF) exposure levels. Geospatial propagation models (NISMap) are implemented and validated for environmental outdoor sources of RFs using spot measurements. Spot and fixed longer-term ELF and RF measurements were done in the environments where children spend most of the time. Moreover, personal measurements were taken in order to assess individual exposure to RF. The exposure data are used to explore their relationships with proximity and/or use of EMF-NIR sources. Characterisation of the EMF-NIR exposure by this combination of methods is intended to overcome problems encountered in other research. The assessment of exposure of INMA cohort children and adolescents living in different regions of Spain to the full frequency range of EMF-NIR extends the characterisation of environmental exposures in this cohort. Together with other data obtained in the project, on socioeconomic and family characteristics and development of the children and adolescents, this will enable to evaluate the complex interaction between health outcomes in children and adolescents and the various environmental factors that surround them.

Modelling Schumann resonances from ELF measurements using non-linear optimization methods

NASA Astrophysics Data System (ADS)

Castro, Francisco; Toledo-Redondo, Sergio; Fornieles, Jesús; Salinas, Alfonso; Portí, Jorge; Navarro, Enrique; Sierra, Pablo

2017-04-01

Schumann resonances (SR) can be found in planetary atmospheres, inside the cavity formed by the conducting surface of the planet and the lower ionosphere. They are a powerful tool to investigate both the electric processes that occur in the atmosphere and the characteristics of the surface and the lower ionosphere. In this study, the measurements are obtained in the ELF (Extremely Low Frequency) Juan Antonio Morente station located in the national park of Sierra Nevada. The three first modes, contained in the frequency band between 6 to 25 Hz, will be considered. For each time series recorded by the station, the amplitude spectrum was estimated by using Bartlett averaging. Then, the central frequencies and amplitudes of the SRs were obtained by fitting the spectrum with non-linear functions. In the poster, a study of nonlinear unconstrained optimization methods applied to the estimation of the Schumann Resonances will be presented. Non-linear fit, also known as optimization process, is the procedure followed in obtaining Schumann Resonances from the natural electromagnetic noise. The optimization methods that have been analysed are: Levenberg-Marquardt, Conjugate Gradient, Gradient, Newton and Quasi-Newton. The functions that the different methods fit to data are three lorentzian curves plus a straight line. Gaussian curves have also been considered. The conclusions of this study are outlined in the following paragraphs: i) Natural electromagnetic noise is better fitted using Lorentzian functions; ii) the measurement bandwidth can accelerate the convergence of the optimization method; iii) Gradient method has less convergence and has a highest mean squared error (MSE) between measurement and the fitted function, whereas Levenberg-Marquad, Gradient conjugate method and Cuasi-Newton method give similar results (Newton method presents higher MSE); v) There are differences in the MSE between the parameters that define the fit function, and an interval from 1% to 5% has been found.

A model explaining synchronization of neuron bioelectric frequency under weak alternating low frequency magnetic field

NASA Astrophysics Data System (ADS)

del Moral, A.; Azanza, María J.

2015-03-01

A biomagnetic-electrical model is presented that explains rather well the experimentally observed synchronization of the bioelectric potential firing rate ("frequency"), f, of single unit neurons of Helix aspersa mollusc under the application of extremely low frequency (ELF) weak alternating (AC) magnetic fields (MF). The proposed model incorporates to our widely experimentally tested model of superdiamagnetism (SD) and Ca2+ Coulomb explosion (CE) from lipid (LP) bilayer membrane (SD-CE model), the electrical quadrupolar long range interaction between the bilayer LP membranes of synchronized neuron pairs, not considered before. The quadrupolar interaction is capable of explaining well the observed synchronization. Actual extension of our SD-CE-model shows that the neuron firing frequency field, B, dependence becomes not modified, but the bioelectric frequency is decreased and its spontaneous temperature, T, dependence is modified. A comparison of the model with synchronization experimental results of pair of neurons under weak (B0 ≅0.2-15 mT) AC-MF of frequency fM=50 Hz is reported. From the deduced size of synchronized LP clusters under B, is suggested the formation of small neuron networks via the membrane lipid correlation.

Evaluation of the aspartate aminotransferase/platelet ratio index and enhanced liver fibrosis tests to detect significant fibrosis due to chronic hepatitis C.

PubMed

Petersen, John R; Stevenson, Heather L; Kasturi, Krishna S; Naniwadekar, Ashutosh; Parkes, Julie; Cross, Richard; Rosenberg, William M; Xiao, Shu-Yuan; Snyder, Ned

2014-04-01

The assessment of liver fibrosis in chronic hepatitis C patients is important for prognosis and making decisions regarding antiviral treatment. Although liver biopsy is considered the reference standard for assessing hepatic fibrosis in patients with chronic hepatitis C, it is invasive and associated with sampling and interobserver variability. Serum fibrosis markers have been utilized as surrogates for a liver biopsy. We completed a prospective study of 191 patients in which blood draws and liver biopsies were performed on the same visit. Using liver biopsies the sensitivity, specificity, and negative and positive predictive values for both aspartate aminotransferase/platelet ratio index (APRI) and enhanced liver fibrosis (ELF) were determined. The patients were divided into training and validation patient sets to develop and validate a clinically useful algorithm for differentiating mild and significant fibrosis. The area under the ROC curve for the APRI and ELF tests for the training set was 0.865 and 0.880, respectively. The clinical sensitivity in separating mild (F0-F1) from significant fibrosis (F2-F4) was 80% and 86.0% with a clinical specificity of 86.7% and 77.8%, respectively. For the validation sets the area under the ROC curve for the APRI and ELF tests was, 0.855 and 0.780, respectively. The clinical sensitivity of the APRI and ELF tests in separating mild (F0-F1) from significant (F2-F4) fibrosis for the validation set was 90.0% and 70.0% with a clinical specificity of 73.3% and 86.7%, respectively. There were no differences between the APRI and ELF tests in distinguishing mild from significant fibrosis for either the training or validation sets (P=0.61 and 0.20, respectively). Using APRI as the primary test followed by ELF for patients in the intermediate zone, would have decreased the number of liver biopsies needed by 40% for the validation set. Overall, use of our algorithm would have decreased the number of patients who needed a liver biopsy from 95 to 24-a 74.7% reduction. This study has shown that the APRI and ELF tests are equally accurate in distinguishing mild from significant liver fibrosis, and combining them into a validated algorithm improves their performance in distinguishing mild from significant fibrosis.

Stratigraphic architecture and gamma ray logs of deeper ramp carbonates (Upper Jurassic, SW Germany)

NASA Astrophysics Data System (ADS)

Pawellek, T.; Aigner, T.

2003-07-01

The objective of this paper is to contribute to the development of sequence stratigraphic models for extensive epicontinental carbonate systems deposited over cratonic areas. Epicontinental carbonates of the SW German Upper Jurassic were analysed in terms of microfacies, sedimentology and sequence stratigraphy based on 2.5 km of core, 70 borehole gamma ray logs and 24 quarries. Facies analysis revealed six major facies belts across the deeper parts of the carbonate ramp, situated generally below fair-weather wave base, and mostly below average storm wave base but in the reach of occasional storm events. Observed stratigraphic patterns differ in some aspects from widely published sequence stratigraphic models: Elementary sedimentary cycles are mostly more or less symmetrical and are, thus, referred to as "genetic sequences" or "genetic units" [AAAPG Bull. 55 (1971) 1137; Frazier, D.E., 1974. Depositional episodes: their relationship to the Quaternary stratigraphic framework in the northwestern portion of the Gulf Basin. University of Texas, Austin, Bureau of Economic Geology Geologicalo Circular 71-1; AAPG Bull. 73 (1989) 125; Galloway, W.E., Hobday, D.K., 1996. Terrigenous Clastic Depositional Systems. 489 pp., Springer; Cross, T.A., Baker, M.R., Chapin, M.S., Clark, M.S., Gardner, M.H., Hanson, M.S., Lessenger, M.A., Little, L.D., McDonough, K.J., Sonnenfeld, M.D., Valasek, D.W., Williams, M.R., Witter, D.N., 1993. Applications of high-resolution sequence stratigraphy to reservoir analysis. Edition Technip 1993, 11-33; Bull. Cent. Rech. Explor. Prod. Elf-Aquitaine 16 (1992) 357; Homewood, P., Mauriaud, P., Lafont, F., 2000. Best practices in sequence stratigraphy. Elf EP Mem. 25, 81 pp.; Homewood, P., Eberli, G.P., 2000. Genetic stratigraphy on the exploration and production scales. Elf EP Mem. 24, 290 pp.], in contrast to the asymmetrical, shallowing-upward "parasequences" of the EXXON approach. Neither sequence boundaries nor maximum flooding surfaces could be clearly delineated. Cycle boundaries are generally not represented by sharp stratal surfaces but are always transitional and, thus, referred to as "turnarounds" [Nor. Pet. Soc. Spec. Publ. 8 (1998) 171]. Several types of genetic sequences were delineated. Both major types of facies and sequences show characteristic gamma ray log signatures. Based on the cycle stacking and the gamma ray patterns, a hierarchy of sequences was recognized, probably driven in part by 100,000- and 400,000-year Milankovitch signals. The cyclicity allowed regional correlations across various depositional environments such as sponge-microbial bioherms and coeval basins. The basin-wide correlation revealed evidence for a subtle clinoform-type stratigraphic architecture along very gentle slopes, rather than a so far assumed simple "layer cake" pattern.

Plasma heating, electric fields and plasma flow by electron beam ionospheric injection

NASA Technical Reports Server (NTRS)

Winckler, J. R.; Erickson, K. N.

1990-01-01

The electric fields and the floating potentials of a Plasma Diagnostics Payload (PDP) located near a powerful electron beam injected from a large sounding rocket into the auroral zone ionosphere have been studied. As the PDP drifted away from the beam laterally, it surveyed a region of hot plasma extending nearly to 60 m radius. Large polarization electric fields transverse to B were imbedded in this hot plasma, which displayed large ELF wave variations and also an average pattern which has led to a model of the plasma flow about the negative line potential of the beam resembling a hydrodynamic vortex in a uniform flow field. Most of the present results are derived from the ECHO 6 sounding rocket mission.

Dynamic Response of a Magnetized Plasma to AN External Source: Application to Space and Solid State Plasmas

NASA Astrophysics Data System (ADS)

Zhou, Huai-Bei

This dissertation examines the dynamic response of a magnetoplasma to an external time-dependent current source. To achieve this goal a new method which combines analytic and numerical techniques to study the dynamic response of a 3-D magnetoplasma to a time-dependent current source imposed across the magnetic field was developed. The set of the cold electron and/or ion plasma equations and Maxwell's equations are first solved analytically in (k, omega)^ace; inverse Laplace and 3 -D complex Fast Fourier Transform (FFT) techniques are subsequently used to numerically transform the radiation fields and plasma currents from the (k, omega) ^ace to the (r, t) space. The dynamic responses of the electron plasma and of the compensated two-component plasma to external current sources are studied separately. The results show that the electron plasma responds to a time -varying current source imposed across the magnetic field by exciting whistler/helicon waves and forming of an expanding local current loop, induced by field aligned plasma currents. The current loop consists of two anti-parallel field-aligned current channels concentrated at the ends of the imposed current and a cross-field current region connecting these channels. The latter is driven by an electron Hall drift. A compensated two-component plasma responds to the same current source as following: (a) For slow time scales tau > Omega_sp{i}{-1} , it generates Alfven waves and forms a non-local current loop in which the ion polarization currents dominate the cross-field current; (b) For fast time scales tau < Omega_sp{i}{-1} , the dynamic response of the compensated two-component plasma is the same as that of the electron plasma. The characteristics of the current closure region are determined by the background plasma density, the magnetic field and the time scale of the current source. This study has applications to a diverse range of space and solid state plasma problems. These problems include current closure in emf inducing tethered satellite systems (TSS), generation of ELF/VLF waves by ionospheric heating, current closure and quasineutrality in thin magnetopause transitions, and short electromagnetic pulse generation in solid state plasmas. The cross-field current in TSS builds up on a time scale corresponding to the whistler waves and results in local current closure. Amplitude modulated HF ionospheric heating generates ELF/VLF waves by forming a horizontal magnetic dipole. The dipole is formed by the current closure in the modified region. For thin transition the time-dependent cross-field polarization field at the magnetopause could be neutralized by the formation of field aligned current loops that close by a cross-field electron Hall current. A moving current source in a solid state plasma results in microwave emission if the speed of the source exceeds the local phase velocity of the helicon or Alfven waves. Detailed analysis of the above problems is presented in the thesis.

In vitro study of the effects of ELF electric fields on gene expression in human epidermal cells.

PubMed

Collard, Jean-Francois; Mertens, Benjamin; Hinsenkamp, Maurice

2011-01-01

An acceleration of differentiation, at the expense of proliferation, is observed after exposure of various biological models to low frequency and low amplitude electric and electromagnetic fields. Following these results showing significant modifications, we try to identify the biological mechanism involved at the cell level through microarray screening. For this study, we use epidermis cultures harvested from human abdominoplasty. Two platinum electrodes are used to apply the electric signal. The gene expressions of 38,500 well-characterized human genes are analyzed using Affymetrix(®) microarray U133 Plus 2.0 chips. The protocol is repeated on three different patients. After three periods of exposure, a total of 24 chips have been processed. After the application of ELF electric fields, the microarray analysis confirms a modification of the gene expression of epidermis cells. Particularly, four up-regulated genes (DKK1, TXNRD1, ATF3, and MME) and one down-regulated gene (MACF1) are involved in the regulation of proliferation and differentiation. Expression of these five genes was also confirmed by real-time rtPCR in all samples used for microarray analysis. These results corroborate an acceleration of cell differentiation at the expense of cell proliferation. © 2010 Wiley-Liss, Inc.

Childhood Leukemia and 50 Hz Magnetic Fields: Findings from the Italian SETIL Case-Control Study

PubMed Central

Salvan, Alberto; Ranucci, Alessandra; Lagorio, Susanna; Magnani, Corrado

2015-01-01

We report on an Italian case-control study on childhood leukemia and exposure to extremely low frequency magnetic fields (ELF-MF). Eligible for inclusion were 745 leukemia cases, aged 0–10 years at diagnosis in 1998–2001, and 1475 sex- and age-matched population controls. Parents of 683 cases and 1044 controls (92% vs. 71%) were interviewed. ELF-MF measurements (24–48 h), in the child’s bedroom of the dwelling inhabited one year before diagnosis, were available for 412 cases and 587 controls included in the main conditional regression analyses. The magnetic field induction was 0.04 μT on average (geometric mean), with 0.6% of cases and 1.6% of controls exposed to >0.3 μT. The impact of changes in the statistical model, exposure metric, and data-set restriction criteria was explored via sensitivity analyses. No exposure-disease association was observed in analyses based on continuous exposure, while analyses based on categorical variables were characterized by incoherent exposure-outcome relationships. In conclusion, our results may be affected by several sources of bias and they are noninformative at exposure levels >0.3 μT. Nonetheless, the study may contribute to future meta- or pooled analyses. Furthermore, exposure levels among population controls are useful to estimate attributable risk. PMID:25689995

Investigation of the broadband ELF turbulence by observations of the FAST satellite

NASA Astrophysics Data System (ADS)

Golovchanskaya, I. V.; Kozelov, B. V.; Despirak, I. V.

2012-07-01

Scaling properties of variable electric fields in the topside ionosphere have been investigated on scales s from ˜30 m to 2 km by FAST electric field observations with sample rate of 512 s-1, in sixteen events of the broadband ELF turbulence. It is shown that down to scales of a few hundred meters, the power of turbulent electric fluctuations is a power law, ˜ s α. Scaling index α derived from the slope of logarithmic diagrams (LD) constructed by the discrete wavelet transform of data can be estimated as α = 2.2 ± 0.3, which is close to α estimate earlier reported for scales 1-30 km by electric field observations of the Dynamics Explorer 2 satellite. The behavior of α index is analyzed near the scale of the order of electron inertial length λe = c/ω0 (ω0 being the electron plasma frequency). At altitudes considered (700-2500 km), λe makes 100-900 m. We demonstrate that at scales ≤λe, a decrease of LD slope and deviation from the power law are typically observed. As pointed out in the discussion, this feature cannot be identified as a transition to the diffusion range, where dissipation of the turbulence occurs.

Intercultural Awareness: Modelling an Understanding of Cultures in Intercultural Communication through English as a Lingua Franca

ERIC Educational Resources Information Center

Baker, Will

2011-01-01

The use of English as a global lingua franca (ELF) raises challenges concerning how we understand the relationship between languages and cultures in intercultural communication. In the dynamic contexts of ELF this relationship needs to be viewed as situated and emergent entailing a new approach to understanding intercultural competence in…

Multi-hop Whistler-Mode ELF/VLF Signals and Triggered Emissions Excited by the HAARP HF Heater

DTIC Science & Technology

2004-12-28

distribution along the field line [ Angerami and Thomas, 1964] to infer the equatorial electron density Neq. This analysis revealed values of L ’ 4.9 and...the ELF/VLF receiver used on RV Tangaroa. References Angerami , J. J., and J. O. Thomas (1964), Studies of planetary atmospheres: 1. The distribution of

English as a Lingua Franca: An Immanent Critique

ERIC Educational Resources Information Center

O'Regan, John P.

2014-01-01

Over the past 15 years or so there has developed a school of thought within English language education and applied linguistics globally which refers to the phenomenon and use of English as a lingua franca (ELF). The thinking of ELF movement researchers has placed their work at the centre of current debates about the form, function and legitimacy…

A Practice-Based Critique of English as a Lingua Franca

ERIC Educational Resources Information Center

Park, Joseph Sung-Yul; Wee, Lionel

2011-01-01

This paper identifies several key issues that have emerged through the debate over English as a Lingua Franca (ELF), and suggests a practice-based perspective--which treats language not as a fixed system but as an emergent product of speakers' practices--as a guide for reconsidering some fundamental assumptions of the ELF research project. In…

Functional characterization of a putative glycine max ELF4 transgenic aradopsis and its role during flowering control

USDA-ARS?s Scientific Manuscript database

Flowering is an important trait in major crops like soybean due to its direct relation to grain production. The circadian clock mediates the perception of seasonal changes in day length and temperature to modulate flowering time. The circadian clock gene EARLY FLOWERING 4 (ELF4) was identified in Ar...

Business Communication in BELF

ERIC Educational Resources Information Center

Kankaanranta, Anne; Louhiala-Salminen, Leena

2007-01-01

The authors' business communication perspective is not in fact that of ESL but rather English as a foreign language (EFL) or, even more so, English as a lingua franca (ELF). To be more specific, they would like to add one more acronym to the list: They teach BELF, by which they refer to ELF for business communication purposes. The authors work as…

A Report of the Center for English as a Lingua Franca (CELF) for Academic Year 2014-2015

ERIC Educational Resources Information Center

Okada, Tricia; Milliner, Brett; Ogane, Ethel; Leichsenring, Andrew; Imai, Mitsuko; Cote, Travis; McBride, Paul

2015-01-01

English as a Lingua Franca (ELF) refers to the use of English as a contact language between people who have different first languages, including native English speakers (Jenkins, 2014). "ELF is simultaneously the consequence and the principal language medium of globalizing processes" (Jenkins, Cogo, & Dewey, 2011, p. 303). In…

The developmental effects of extremely low frequency electric fields on visual and somatosensory evoked potentials in adult rats.

PubMed

Gok, Deniz Kantar; Akpinar, Deniz; Hidisoglu, Enis; Ozen, Sukru; Agar, Aysel; Yargicoglu, Piraye

2016-01-01

The purpose of our study was to investigate the developmental effects of extremely low frequency electric fields (ELF-EFs) on visual evoked potentials (VEPs) and somatosensory-evoked potentials (SEPs) and to examine the relationship between lipid peroxidation and changes of these potentials. In this context, thiobarbituric acid reactive substances (TBARS) levels were determined as an indicator of lipid peroxidation. Wistar albino female rats were divided into four groups; Control (C), gestational (prenatal) exposure (Pr), gestational+ postnatal exposure (PP) and postnatal exposure (Po) groups. Pregnant rats of Pr and PP groups were exposed to 50 Hz electric field (EF) (12 kV/m; 1 h/day), while those of C and Po groups were placed in an inactive system during pregnancy. Following parturition, rats of PP and Po groups were exposed to ELF-EFs whereas rats of C and Pr groups were kept under the same experimental conditions without being exposed to any EF during 68 days. On postnatal day 90, rats were prepared for VEP and SEP recordings. The latencies of VEP components in all experimental groups were significantly prolonged versus C group. For SEPs, all components of PP group, P2, N2 components of Pr group and P1, P2, N2 components of Po group were delayed versus C group. As brain TBARS levels were significantly increased in Pr and Po groups, retina TBARS levels were significantly elevated in all experimental groups versus C group. In conclusion, alterations seen in evoked potentials, at least partly, could be explained by lipid peroxidation in the retina and brain.

Quantifying environmental limiting factors on tree cover using geospatial data.

PubMed

Greenberg, Jonathan A; Santos, Maria J; Dobrowski, Solomon Z; Vanderbilt, Vern C; Ustin, Susan L

2015-01-01

Environmental limiting factors (ELFs) are the thresholds that determine the maximum or minimum biological response for a given suite of environmental conditions. We asked the following questions: 1) Can we detect ELFs on percent tree cover across the eastern slopes of the Lake Tahoe Basin, NV? 2) How are the ELFs distributed spatially? 3) To what extent are unmeasured environmental factors limiting tree cover? ELFs are difficult to quantify as they require significant sample sizes. We addressed this by using geospatial data over a relatively large spatial extent, where the wall-to-wall sampling ensures the inclusion of rare data points which define the minimum or maximum response to environmental factors. We tested mean temperature, minimum temperature, potential evapotranspiration (PET) and PET minus precipitation (PET-P) as potential limiting factors on percent tree cover. We found that the study area showed system-wide limitations on tree cover, and each of the factors showed evidence of being limiting on tree cover. However, only 1.2% of the total area appeared to be limited by the four (4) environmental factors, suggesting other unmeasured factors are limiting much of the tree cover in the study area. Where sites were near their theoretical maximum, non-forest sites (tree cover < 25%) were primarily limited by cold mean temperatures, open-canopy forest sites (tree cover between 25% and 60%) were primarily limited by evaporative demand, and closed-canopy forests were not limited by any particular environmental factor. The detection of ELFs is necessary in order to fully understand the width of limitations that species experience within their geographic range.

Population Pharmacokinetics of Colistin Methanesulfonate in Rats: Achieving Sustained Lung Concentrations of Colistin for Targeting Respiratory Infections

PubMed Central

W. S. Yapa, Shalini; Li, Jian; Porter, Christopher J. H.; Nation, Roger L.

2013-01-01

Colistin methanesulfonate (CMS), the inactive prodrug of colistin, is administered by inhalation for the management of respiratory infections. However, limited pharmacokinetic data are available for CMS and colistin following pulmonary delivery. This study investigates the pharmacokinetics of CMS and colistin following intravenous (i.v.) and intratracheal (i.t.) administration in rats and determines the targeting advantage after direct delivery into the lungs. In addition to plasma, bronchoalveolar lavage (BAL) fluid was collected to quantify drug concentrations in lung epithelial lining fluid (ELF). The resulting data were analyzed using a population modeling approach in S-ADAPT. A three-compartment model described the disposition of both compounds in plasma following i.v. administration. The estimated mean clearance from the central compartment was 0.122 liters/h for CMS and 0.0657 liters/h for colistin. Conversion of CMS to colistin from all three compartments was required to fit the plasma data. The fraction of the i.v. dose converted to colistin in the systemic circulation was 0.0255. Two BAL fluid compartments were required to reflect drug kinetics in the ELF after i.t. dosing. A slow conversion of CMS (mean conversion time [MCTCMS] = 3.48 h) in the lungs contributed to high and sustained concentrations of colistin in ELF. The fraction of the CMS dose converted to colistin in ELF (fm,ELF = 0.226) was higher than the corresponding fractional conversion in plasma after i.v. administration. In conclusion, pulmonary administration of CMS achieves high and sustained exposures of colistin in lungs for targeting respiratory infections. PMID:23917323

Magnetic Earth Ionosphere Resonant Frequencies (MEIRF) project

NASA Technical Reports Server (NTRS)

Spaniol, Craig

1993-01-01

The West Virginia State College Community College Division NASA Magnetic Earth Ionosphere Resonant Frequencies (MEIRF) study is described. During this contract period, the two most significant and professionally rewarding events were the presentation of the research activity at the Sir Isaac Newton Conference in St. Petersburg, Russia, and the second Day of Discovery Conference, focusing on economic recovery in West Virginia. An active antenna concept utilizing a signal feedback principle similar to regenerative receivers used in early radio was studied. The device has potential for ELF research and other commercial applications for improved signal reception. Finally, work continues to progress on the development of a prototype monitoring station. Signal monitoring, data display, and data storage are major areas of activity. In addition, we plan to continue our dissemination of research activity through presentations at seminars and other universities.

English as an Asian Lingua Franca and the Multilingual Model of ELT

ERIC Educational Resources Information Center

Kirkpatrick, Andy

2011-01-01

The concept of English as a lingua franca (ELF) has recently caused a great deal of controversy, much of it based on a misunderstanding of ELF. In this presentation, I shall first provide a brief history of lingua francas and then compare and contrast two major Asian lingua francas--Bahasa Indonesia and Putonghua--in order to show how different…

ELF on a Mushroom: The Overnight Growth in English as a Lingua Franca

ERIC Educational Resources Information Center

Sowden, Colin

2012-01-01

In an effort to curtail native-speaker dominance of global English, and in recognition of the growing role of the language among non-native speakers from different first-language backgrounds, some academics have been urging the teaching of English as a Lingua Franca (ELF). Although at first this proposal seems to offer a plausible alternative to…

When Five Words Are Not Enough: A Conceptual and Terminological Discussion of English as a Lingua Franca

ERIC Educational Resources Information Center

Friedrich, Patricia; Matsuda, Aya

2010-01-01

The goal of this article is to (re)define key terminology in the study of English as a lingua franca (ELF). Although the diverse perspectives and ideological standpoints represented in competing definitions of terms is appreciated, a critical conversation on definition and interpretation of ELF and other related concepts is crucial in providing a…

Considering New Perspectives in ELT in Colombia: From EFL to ELF

ERIC Educational Resources Information Center

Fernando Macías, Diego

2010-01-01

This article aims to explore the characteristics of English as a lingua franca (ELF) as an alternative to English Language Teaching (ELT) in Colombia. It focuses initially on the role played by English in the country and on what the English as a Foreign Language (EFL) model has offered the teaching of English. This is followed by considerations…

Teaching ELF as a Motivation Source for Learners: An Action Research Study

ERIC Educational Resources Information Center

Muyan, Emrah; Tunaz, Mehmet

2017-01-01

The purpose of this study was to explore if teaching ELF would help students change their beliefs about language and language learning. Firstly, students were interviewed in person, and they were found to have a lack of motivation and negative attitudes towards learning English with standard norms. It was also noticed that the students are not…

The ejector-loop fermenter: Description and performance of the apparatus.

PubMed

Moresi, M; Bartolo Gianturco, G; Sebastiani, E

1983-12-01

A novel fermentation unit, the ejector-loop fermenter (ELF), consisting of an outer-loop tower fermenter, a centrifugal pump, a plate-heat exchanger, and a gas-liquid ejector, was designed and constructed. Aeration was achieved by continuously recirculating the fermentation medium through two different nozzle devices instead of using the traditional expensive air compressor. By carrying out a whey fermentation with Kluyveromyces fragilis as the test organism, either in the ELF or in conventional stirred fermenter, it was possible to confirm that the high sheat streses and mixing shock occurring in the ejector nozzle and diffuser sections did not affect microbial growth. Within the range of experimental power consumption per unit volume (-0.1-5 kW/m(3)), the oxygen transfer capability of the ELF per unit power input was found to vary from 1 to 2.5 kg O(2) kW(-1)h(-1). Moreover, it is shown that there is suficient room for improvement in the performance of the ELF unit by care fully designing the aeration device. In fact, at constant volumetric oxygen transfer coefficient, the power consumpotion per unit volume in a 4-mm nozzle was found to be about 40% less than that in a 6-mm nozzle.

Extremely Luminous Far-infrared Sources (ELFS)

NASA Technical Reports Server (NTRS)

Harwit, Martin; Houck, James R.; Soifer, B. Thomas; Palumbo, Giorgio G. C.

1987-01-01

The Infrared Astronomical Satellite (IRAS) survey uncovered a class of Extremely Luminous Far Infrared Sources (ELFS), exhibiting luminosities up to and occasionally exceeding 10 to the 12th power L sub 0. Arguments are presented to show that sources with luminosities L equal to or greater than 3 x 10 to the 10th power L sub 0 may represent gas rich galaxies in collision. The more conventional explanation of these sources as sites of extremely active star formation fails to explain the observed low optical luminosities of ELFS as well as their high infrared excess. In contrast, a collisional model heats gas to a temperature of approx. 10 to the 6th power K where cooling takes place in the extreme ultraviolet. The UV is absorbed by dust and converted into far infrared radiation (FIR) without generation of appreciable optical luminosity. Gas recombination as it cools generates a Lyman alpha photon only once for every two extreme ultraviolet approx. 50eV photons emitted by the 10 to the 6th power gas. That accounts for the high infrared excess. Finally, the model also is able to explain the observed luminosity distribution of ELFS as well as many other traits.

Electron localisation in static and time-dependent one-dimensional model systems

NASA Astrophysics Data System (ADS)

Durrant, T. R.; Hodgson, M. J. P.; Ramsden, J. D.; Godby, R. W.

2018-02-01

The most direct signature of electron localisation is the tendency of an electron in a many-body system to exclude other same-spin electrons from its vicinity. By applying this concept directly to the exact many-body wavefunction, we find that localisation can vary considerably between different ground-state systems, and can also be strongly disrupted, as a function of time, when a system is driven by an applied electric field. We use this measure to assess the well-known electron localisation function (ELF), both in its approximate single-particle form (often applied within density-functional theory) and its full many-particle form. The full ELF always gives an excellent description of localisation, but the approximate ELF fails in time-dependent situations, even when the exact Kohn-Sham orbitals are employed.

Preliminary crystallographic analysis of mouse Elf3 C-terminal DNA-binding domain in complex with type II TGF-[beta] receptor promoter DNA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agarkar, Vinod B.; Babayeva, Nigar D.; Rizzino, Angie

2010-10-08

Ets proteins are transcription factors that activate or repress the expression of genes that are involved in various biological processes, including cellular proliferation, differentiation, development, transformation and apoptosis. Like other Ets-family members, Elf3 functions as a sequence-specific DNA-binding transcriptional factor. A mouse Elf3 C-terminal fragment (amino-acid residues 269-371) containing the DNA-binding domain has been crystallized in complex with mouse type II TGF-{beta} receptor promoter (TR-II) DNA. The crystals belonged to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 42.66, b = 52, c = 99.78 {angstrom}, and diffracted to a resolution of 2.2 {angstrom}.

A biomonitoring study of genotoxic risk to workers of transformers and distribution line stations.

PubMed

Celikler, Serap; Aydemir, Nilufer; Vatan, Ozgur; Kurtuldu, Sevim; Bilaloglu, Rahmi

2009-12-01

A cytogenetic monitoring study was carried out on a group of workers from transformer and distribution line stations in the Bursa province of Turkey, to investigate the genotoxic risk of occupational exposure to extremely low frequency electric (ELF) and magnetic fields (EMF). Cytogenetic analysis, namely chromosomal aberrations (CAs) and micronucleus (MN) tests were performed on a strictly selected group of 55 workers and compared to 17 controls. CA and MN frequencies in electrical workers appeared significantly higher than in controls (p < 0.001, 0.05, respectively). The frequency of CA in exposed groups were significantly enhanced with the years of exposure (p < 0.01). The effect of smoking on the level of CA and MN was not significant in the control and exposure groups. The results of this study demonstrated that a significant induction of cytogenetic damage in peripheral lymphocytes of workers engaged to occupational exposure to ELMF in electric transformer and distribution stations.

The Habitat Factor in ELF(A)--English as a Lingua Franca (In Academic Settings)--And English for Plurilingual Academic Purposes

ERIC Educational Resources Information Center

Schaller-Schwaner, Iris

2015-01-01

This article considers a case of local language socialization and accommodation in a multilingual community of practice: the use of English as an additional academic language for specific purposes at a bilingual Swiss university and its implications for teaching. The acronym ELF(A) is used throughout as short for English as a Lingua Franca (in…

Bespoke Language Teaching (BLT): A Proposal for a Theoretical Framework. the Case of EFL/ELF for Italians

ERIC Educational Resources Information Center

Santipolo, Matteo

2017-01-01

This paper deals with the problems of teaching English as a foreign language (EFL) and as a lingua franca (ELF) in the Italian educational system and, in particular, with introducing language variation in the English class. After briefly illustrating how English teaching has changed in the last few decades, an outline is drawn of what happens in…

S-LOCUS EARLY FLOWERING 3 Is Exclusively Present in the Genomes of Short-Styled Buckwheat Plants that Exhibit Heteromorphic Self-Incompatibility

PubMed Central

Aii, Jotaro; Abe, Tomoko; Matsumoto, Daiki; Sato, Shingo; Hayashi, Yoriko; Ohnishi, Ohmi; Ota, Tatsuya

2012-01-01

The different forms of flowers in a species have attracted the attention of many evolutionary biologists, including Charles Darwin. In Fagopyrum esculentum (common buckwheat), the occurrence of dimorphic flowers, namely short-styled and long-styled flowers, is associated with a type of self-incompatibility (SI) called heteromorphic SI. The floral morphology and intra-morph incompatibility are both determined by a single genetic locus named the S-locus. Plants with short-styled flowers are heterozygous (S/s) and plants with long-styled flowers are homozygous recessive (s/s) at the S-locus. Despite recent progress in our understanding of the molecular basis of flower development and plant SI systems, the molecular mechanisms underlying heteromorphic SI remain unresolved. By examining differentially expressed genes from the styles of the two floral morphs, we identified a gene that is expressed only in short-styled plants. The novel gene identified was completely linked to the S-locus in a linkage analysis of 1,373 plants and had homology to EARLY FLOWERING 3. We named this gene S-LOCUS EARLY FLOWERING 3 (S-ELF3). In an ion-beam-induced mutant that harbored a deletion in the genomic region spanning S-ELF3, a phenotype shift from short-styled flowers to long-styled flowers was observed. Furthermore, S-ELF3 was present in the genome of short-styled plants and absent from that of long-styled plants both in world-wide landraces of buckwheat and in two distantly related Fagopyrum species that exhibit heteromorphic SI. Moreover, independent disruptions of S-ELF3 were detected in a recently emerged self-compatible Fagopyrum species and a self-compatible line of buckwheat. The nonessential role of S-ELF3 in the survival of individuals and the prolonged evolutionary presence only in the genomes of short-styled plants exhibiting heteromorphic SI suggests that S-ELF3 is a suitable candidate gene for the control of the short-styled phenotype of buckwheat plants. PMID:22312442

Representative Electromagnetic Field Intensities Near the Clam Lake, Wisconsin and Republic, Michigan ELF (Extremely Low Frequency) Facilities.

DTIC Science & Technology

1984-01-01

wo 60 l s. 0 a -, 3" 0 . I, ,,. 0) 144 3.44 Y., 4 c 4 a ll.,m ._ - ,.,. .. ,. ,3k ,, -9 q𔃾!~ II W3 Q n o i i TIE 15 k USL . i jI O 1 A W.iW8 WA...stakes penetrate soil to a known depth at two points one meter apart. The potential difference between the stakes is measured with a tuned voltmeter to... soil below 100 microvolts per meter (Tables A-5, A-6 and A-12) are not listed. Variations were observed during measurements of such very low intensities

High Power HF Excitation of Low Frequency Stimulated Electrostatic Waves in the Ionospheric Plasma over HAARP

NASA Astrophysics Data System (ADS)

Bernhardt, Paul; Selcher, Craig A.

High Power electromagnetic (EM) waves transmitted from the HAARP facility in Alaska can excite low frequency electrostatic waves by several processes including (1) direct magnetized stimulated Brillouin scatter (MSBS) and (2) parametric decay of high frequency electrostatic waves into electron and ion Bernstein waves. Either an ion acoustic (IA) wave with a frequency less than the ion cyclotron frequency (fCI) or an electrostatic ion cyclotron (EIC) wave just above fCI can be produced by MSBS. The coupled equations describing the MSBS instabil-ity show that the production of both IA and EIC waves is strongly influenced by the wave propagation direction relative to the background magnetic field. Experimental observations of stimulated electromagnetic emissions (SEE) using the HAARP transmitter in Alaska have confirmed the theoretical predictions that only IA waves are excited for propagation along the magnetic zenith and that EIC waves can only be detected with oblique propagation angles. The electron temperature in the heated plasma is obtained from the IA spectrum offsets from the pump frequency. The ion composition can be determined from the measured EIC frequency. Near the second harmonic of the electron cyclotron frequency, the EM pump wave is converted into an electron Bernstein (EB) wave that decays into another EB wave and an ion Bernstein (IB) wave. Strong cyclotron resonance with the EB wave leads to acceleration of the electrons. Ground based SEE observations are related to the theory of low-frequency electrostatic wave generation.

Stability evaluation of reference genes for gene expression analysis by RT-qPCR in soybean under different conditions.

PubMed

Wan, Qiao; Chen, Shuilian; Shan, Zhihui; Yang, Zhonglu; Chen, Limiao; Zhang, Chanjuan; Yuan, Songli; Hao, Qinnan; Zhang, Xiaojuan; Qiu, Dezhen; Chen, Haifeng; Zhou, Xinan

2017-01-01

Real-time quantitative reverse transcription PCR is a sensitive and widely used technique to quantify gene expression. To achieve a reliable result, appropriate reference genes are highly required for normalization of transcripts in different samples. In this study, 9 previously published reference genes (60S, Fbox, ELF1A, ELF1B, ACT11, TUA5, UBC4, G6PD, CYP2) of soybean [Glycine max (L.) Merr.] were selected. The expression stability of the 9 genes was evaluated under conditions of biotic stress caused by infection with soybean mosaic virus, nitrogen stress, across different cultivars and developmental stages. ΔCt and geNorm algorithms were used to evaluate and rank the expression stability of the 9 reference genes. Results obtained from two algorithms showed high consistency. Moreover, results of pairwise variation showed that two reference genes were sufficient to normalize the expression levels of target genes under each experimental setting. For virus infection, ELF1A and ELF1B were the most stable reference genes for accurate normalization. For different developmental stages, Fbox and G6PD had the highest expression stability between two soybean cultivars (Tanlong No. 1 and Tanlong No. 2). ELF1B and ACT11 were identified as the most stably expressed reference genes both under nitrogen stress and among different cultivars. The results showed that none of the candidate reference genes were uniformly expressed at different conditions, and selecting appropriate reference genes was pivotal for gene expression studies with particular condition and tissue. The most stable combination of genes identified in this study will help to achieve more accurate and reliable results in a wide variety of samples in soybean.

Evaluation of the concentration of marbofloxacin in alveolar macrophages and pulmonary epithelial lining fluid after administration in dogs.

PubMed

Boothe, Harry W; Jones, Sarah A; Wilkie, W Scott; Boeckh, Albert; Stenstrom, Kristol K; Boothe, Dawn M

2005-10-01

To determine concentrations of marbofloxacin in alveolar macrophages (AMs) and epithelial lining fluid (ELF) and compare those concentrations with plasma concentrations in healthy dogs. 12 adult mixed-breed and purebred hounds. 10 dogs received orally administered marbofloxacin at a dosage of 2.75 mg/kg every 24 hours for 5 days. Two dogs served as nontreated controls. Fiberoptic bronchoscopy and bronchoalveolar lavage procedures were performed while dogs were anesthetized with propofol, approximately 6 hours after the fifth dose. The concentrations of marbofloxacin in plasma and bronchoalveolar fluid (cell and supernatant fractions) were determined by use of high-performance liquid chromatography with detection of fluorescence. Mean +/- SD plasma marbofloxacin concentrations 2 and 6 hours after the fifth dose were 2.36 +/- 0.52 microg/mL and 1.81 +/- 0.21 microg/mL, respectively. Mean +/- SD marbofloxacin concentration 6 hours after the fifth dose in AMs (37.43 +/- 24.61 microg/mL) was significantly greater than that in plasma (1.81 +/- 0.21 microg/mL) and ELF (0.82 +/- 0.34 microg/mL), resulting in a mean AM concentration-to-plasma concentration ratio of 20.4, a mean AM:ELF ratio of 60.8, and a mean ELF-to-plasma ratio of 0.46. Marbofloxacin was not detected in any samples from control dogs. Marbofloxacin concentrations in AMs were greater than the mean inhibitory concentrations of major bacterial pathogens in dogs. Results indicated that marbofloxacin accumulates in AMs at concentrations exceeding those reached in plasma and ELF The accumulation of marbofloxacin in AMs may facilitate treatment for susceptible intracellular pathogens or infections associated with pulmonary macrophage infiltration.

Robust sampling-sourced numerical retrieval algorithm for optical energy loss function based on log-log mesh optimization and local monotonicity preserving Steffen spline

NASA Astrophysics Data System (ADS)

Maglevanny, I. I.; Smolar, V. A.

2016-01-01

We introduce a new technique of interpolation of the energy-loss function (ELF) in solids sampled by empirical optical spectra. Finding appropriate interpolation methods for ELFs poses several challenges. The sampled ELFs are usually very heterogeneous, can originate from various sources thus so called "data gaps" can appear, and significant discontinuities and multiple high outliers can be present. As a result an interpolation based on those data may not perform well at predicting reasonable physical results. Reliable interpolation tools, suitable for ELF applications, should therefore satisfy several important demands: accuracy and predictive power, robustness and computational efficiency, and ease of use. We examined the effect on the fitting quality due to different interpolation schemes with emphasis on ELF mesh optimization procedures and we argue that the optimal fitting should be based on preliminary log-log scaling data transforms by which the non-uniformity of sampled data distribution may be considerably reduced. The transformed data are then interpolated by local monotonicity preserving Steffen spline. The result is a piece-wise smooth fitting curve with continuous first-order derivatives that passes through all data points without spurious oscillations. Local extrema can occur only at grid points where they are given by the data, but not in between two adjacent grid points. It is found that proposed technique gives the most accurate results and also that its computational time is short. Thus, it is feasible using this simple method to address practical problems associated with interaction between a bulk material and a moving electron. A compact C++ implementation of our algorithm is also presented.

Substantial Targeting Advantage Achieved by Pulmonary Administration of Colistin Methanesulfonate in a Large-Animal Model

PubMed Central

Nguyen, Tri-Hung; Lieu, Linh Thuy; Nguyen, Gary; Bischof, Robert J.; Meeusen, Els N.; Li, Jian; Nation, Roger L.

2016-01-01

ABSTRACT Colistin, administered as its inactive prodrug colistin methanesulfonate (CMS), is often used in multidrug-resistant Gram-negative pulmonary infections. The CMS and colistin pharmacokinetics in plasma and epithelial lining fluid (ELF) following intravenous and pulmonary dosing have not been evaluated in a large-animal model with pulmonary architecture similar to that of humans. Six merino sheep (34 to 43 kg body weight) received an intravenous or pulmonary dose of 4 to 8 mg/kg CMS (sodium) or 2 to 3 mg/kg colistin (sulfate) in a 4-way crossover study. Pulmonary dosing was achieved via jet nebulization through an endotracheal tube cuff. CMS and colistin were quantified in plasma and bronchoalveolar lavage fluid (BALF) samples by high-performance liquid chromatography (HPLC). ELF concentrations were calculated via the urea method. CMS and colistin were comodeled in S-ADAPT. Following intravenous CMS or colistin administration, no concentrations were quantifiable in BALF samples. Elimination clearance was 1.97 liters/h (4% interindividual variability) for CMS (other than conversion to colistin) and 1.08 liters/h (25%) for colistin. On average, 18% of a CMS dose was converted to colistin. Following pulmonary delivery, colistin was not quantifiable in plasma and CMS was detected in only one sheep. Average ELF concentrations (standard deviations [SD]) of formed colistin were 400 (243), 384 (187), and 184 (190) mg/liter at 1, 4, and 24 h after pulmonary CMS administration. The population pharmacokinetic model described well CMS and colistin in plasma and ELF following intravenous and pulmonary administration. Pulmonary dosing provided high ELF and low plasma colistin concentrations, representing a substantial targeting advantage over intravenous administration. Predictions from the pharmacokinetic model indicate that sheep are an advantageous model for translational research. PMID:27821445

Enhanced production of IGF‐I in the lungs of fibroproliferative ARDS patients

PubMed Central

Andonegui, Graciela; Krein, Peter M.; Mowat, Connie; Brisebois, Ronald; Doig, Christopher; Green, Francis H. Y.; Léger, Caroline; Winston, Brent W.

2014-01-01

Abstract Insulin‐Like Growth Factor I (IGF‐I) has been identified in the lungs of individuals with fibrotic lung diseases. In a previous retrospective study, we showed enhanced IGF‐I immunoreactivity in individuals with fibroproliferative acute respiratory distress syndrome (FP‐ARDS), but we were unable to determine if this correlation was causative. This study was undertaken to prospectively investigate whether IGF‐I expression correlated with the fibroproliferative process and whether IGF‐I was induced and made in the lungs. We measured IGF‐I and procollagen III peptide (PCP‐III) in the epithelial lining fluid (ELF) from controls, early ALI/ARDS patients and FP‐ARDS patients. We also measured IGF‐I mRNA and immunoreactivity from controls and FP‐ARDS patient lung biopsies. We determined the level of lung permeability by measuring albumin and urea levels in ELF and serum. Our data show that IGF‐I is significantly increased in the ELF in FP‐ARDS patients. A significant correlation between IGF‐I and PCP‐III in the ELF of FP‐ARDS patients is found. IGF‐I mRNA is elevated in the FP‐ARDS lung biopsies. Our data suggest that IGF‐I found in the lungs of FP‐ARDS patients results from both increased lung permeability and local production of IGF‐I. The role of IGF‐I in the fibroproliferative process in the lungs has recently been confirmed in an animal model of lung fibroproliferation. This study importantly suggest that IGF‐I protein is made in the lungs of FP‐ARDS patients and correlates with increased levels of ELF PCP‐III, implicating a role for IGF‐I in the fibroproliferative process in humans. PMID:25367695

Enhanced production of IGF-I in the lungs of fibroproliferative ARDS patients.

PubMed

Andonegui, Graciela; Krein, Peter M; Mowat, Connie; Brisebois, Ronald; Doig, Christopher; Green, Francis H Y; Léger, Caroline; Winston, Brent W

2014-11-01

Insulin-Like Growth Factor I (IGF-I) has been identified in the lungs of individuals with fibrotic lung diseases. In a previous retrospective study, we showed enhanced IGF-I immunoreactivity in individuals with fibroproliferative acute respiratory distress syndrome (FP-ARDS), but we were unable to determine if this correlation was causative. This study was undertaken to prospectively investigate whether IGF-I expression correlated with the fibroproliferative process and whether IGF-I was induced and made in the lungs. We measured IGF-I and procollagen III peptide (PCP-III) in the epithelial lining fluid (ELF) from controls, early ALI/ARDS patients and FP-ARDS patients. We also measured IGF-I mRNA and immunoreactivity from controls and FP-ARDS patient lung biopsies. We determined the level of lung permeability by measuring albumin and urea levels in ELF and serum. Our data show that IGF-I is significantly increased in the ELF in FP-ARDS patients. A significant correlation between IGF-I and PCP-III in the ELF of FP-ARDS patients is found. IGF-I mRNA is elevated in the FP-ARDS lung biopsies. Our data suggest that IGF-I found in the lungs of FP-ARDS patients results from both increased lung permeability and local production of IGF-I. The role of IGF-I in the fibroproliferative process in the lungs has recently been confirmed in an animal model of lung fibroproliferation. This study importantly suggest that IGF-I protein is made in the lungs of FP-ARDS patients and correlates with increased levels of ELF PCP-III, implicating a role for IGF-I in the fibroproliferative process in humans. © 2014 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Pharmacokinetics and Pharmacodynamics of Minocycline against Acinetobacter baumannii in a Neutropenic Murine Pneumonia Model.

PubMed

Zhou, Jian; Ledesma, Kimberly R; Chang, Kai-Tai; Abodakpi, Henrietta; Gao, Song; Tam, Vincent H

2017-05-01

Multidrug-resistant (MDR) Acinetobacter baumannii is increasingly more prevalent in nosocomial infections. Although in vitro susceptibility of A. baumannii to minocycline is promising, the in vivo efficacy of minocycline has not been well established. In this study, the in vivo activity of minocycline was evaluated in a neutropenic murine pneumonia model. Specifically, we investigated the relationship between minocycline exposure and bactericidal activity using five A. baumannii isolates with a broad range of susceptibility (MIC ranged from 0.25 mg/liter to 16 mg/liter). The pharmacokinetics of minocycline (single dose of 25 mg/kg of body weight, 50 mg/kg, 100 mg/kg, and a humanized regimen, given intraperitoneally) in serum and epithelial lining fluid (ELF) were characterized. Dose linearity was observed for doses up to 50 mg/kg and pulmonary penetration ratios (area under the concentration-time curve in ELF from 0 to 24 h [AUC ELF,0-24 ]/area under the concentration time curve in serum from 0 to 24 h [AUC serum,0-24 ]) ranged from 2.5 to 2.8. Pharmacokinetic-pharmacodynamics (PK-PD) index values in ELF for various dose regimens against different A. baumannii isolates were calculated. The maximum efficacy at 24 h was approximately 1.5-log-unit reduction of pulmonary bacterial burdens from baseline. The AUC/MIC ratio was the PK-PD index most closely correlating to the bacterial burden ( r 2 = 0.81). The required AUC ELF,0-24 /MIC for maintaining stasis and achieving 1-log-unit reduction were 140 and 410, respectively. These findings could guide the treatment of infections caused by A. baumannii using minocycline in the future. Additional studies to examine resistance development during therapy are warranted. Copyright © 2017 American Society for Microbiology.

Comparison of endogenous loss and maintenance need for minerals in rainbow trout (Oncorhynchus mykiss) fed fishmeal or plant ingredient-based diets.

PubMed

Antony Jesu Prabhu, P; Kaushik, S J; Mariojouls, C; Surget, A; Fontagné-Dicharry, S; Schrama, J W; Geurden, I

2015-02-01

Mineral needs as affected by changes in dietary protein and oil sources were studied in rainbow trout. Duplicate groups (n = 30 fish per replicate) of rainbow trout (initial BW: 37 g) were fed either a fish meal/fish oil-based (M) or a complete plant ingredient (V)-based diet at four graded ration (R) levels [apparent satiation (AS), R75, R50 and R25 % of AS]; one treatment group was maintained under starvation. The feeding trial lasted 12 weeks at a water temperature of 17 °C. Dietary intake, apparent digestibility and initial and final whole-body composition data were used to calculate mineral gain which was regressed against digestible mineral intake (both expressed as mg or µg kg(-0.8) day(-1)). Starvation loss (SL), endogenous loss of fed fish (ELF, y-intercept at x = 0) and point of intake for zero balance (PZB, x-intercept at y = 0) were used as estimates of maintenance requirements. SL provided the lowest estimate, ELF provided the net requirement of a mineral for maintenance and PZB provided the digestible dietary intake required to meet maintenance (SL < ELF < PZB). Dietary ingredient composition did not significantly affect the digestible mineral supply required for maintenance (PZB) for any of the minerals (P, Mg, K, Cu and Zn) studied. However, ELF of micro-minerals such as Cu and Zn were significantly affected. The ELF of Cu was significantly lower and that of Zn was significantly higher in V group compared with M-fed fish. Further studies on the effects of such changes in dietary formulations on micro-mineral metabolism are warranted.

ELF and ALEX SURF WINTER WAVES: Lidar Intercomparison of Aerosol and Water Vapor Measurements in the Baltimore-Washington Metropolitan Area During the Winter Water Vapor Validation Experiments (WAVES) 2008 campaign.

NASA Astrophysics Data System (ADS)

Delgado, R.; Weldegaber, M.; Wilson, R. C.; McMillan, W.; McCann, K. J.; Woodman, M.; Demoz, B.; Adam, M.; Connell, R.; Venable, D.; Joseph, E.; Rabenhorst, S.; Twigg, L.; McGee, T.; Whiteman, D. N.; Hoff, R. M.

2008-12-01

Elastic and Raman lidar measurements were conducted to measure the vertical distribution of aerosols and water vapor during the Water Vapor Validation Experiments (WAVES) 2008 campaign by the University of Maryland Baltimore County (UMBC) Atmospheric Lidar Group at UMBC, at the same time as measurements at Howard University's Beltsville Research Station (26.5 km distant). The lidar profiles of atmospheric water vapor and aerosols allowed comparison for AURA/Aqua retrieval studies, by performing instrument accuracy assessments and data, generated by various independent active and passive remote sensing instruments for case studies of regional water vapor and aerosol sub-pixel variability. Integration of the lidar water vapor mixing ratios has been carried out to generate a column precipitable water vapor timeseries that can be compared to UMBC's SUOMINET station and Baltimore Bomem Atmospheric Emitted Radiance Interferometer (BBAERI). Changes in atmospheric aerosol concentration and water vapor mixing ratios due to meteorological events observed in the lidar timeseries have been correlated to the vertical temperature timeseries of BBAERI and to modeling of the air mass over the Baltimore-Washington metro area with the Weather Research and Forecasting (WRF) model.

Nonlocal theory of electromagnetic wave decay into two electromagnetic waves in a rippled density plasma channel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sati, Priti; Tripathi, V. K.

Parametric decay of a large amplitude electromagnetic wave into two electromagnetic modes in a rippled density plasma channel is investigated. The channel is taken to possess step density profile besides a density ripple of axial wave vector. The density ripple accounts for the momentum mismatch between the interacting waves and facilitates nonlinear coupling. For a given pump wave frequency, the requisite ripple wave number varies only a little w.r.t. the frequency of the low frequency decay wave. The radial localization of electromagnetic wave reduces the growth rate of the parametric instability. The growth rate decreases with the frequency of lowmore » frequency electromagnetic wave.« less

Observation of frequency cutoff for self-excited dust acoustic waves

NASA Astrophysics Data System (ADS)

Nosenko, V.; Zhdanov, S. K.; Morfill, G. E.; Kim, S.-H.; Heinrich, J.; Merlino, R. L.

2009-11-01

Complex (dusty) plasmas consist of fine solid particles suspended in a weakly ionized gas. Complex plasmas are excellent model systems to study wave phenomena down to the level of individual ``atoms''. Spontaneously excited dust acoustic waves were observed with high temporal resolution in a suspension of micron-size kaolin particles in a dc discharge in argon. Wave activity was found at frequencies as high as 400 Hz. At high wave numbers, the wave dispersion relation was acoustic-like (frequency proportional to wave number). At low wave numbers, the wave frequency did not tend to zero, but reached a cutoff frequency fc instead. The value of fc declined with distance from the anode. We propose a simple model that explains the observed cutoff by particle confinement in plasma. The existence of a cutoff frequency is very important for the propagation of waves: the waves excited above fc are propagating, and those below fc are evanescent.