Very Low Frequency Electromagnetics

Abstract: The potential harmful effects of sleeping next to mobile phone or laptop chargers, focusing on electromagnetic field (EMF) emissions and associated health concerns. While chargers emit non-ionizing EMFs, primarily in the Extremely Low Frequency (ELF) range, studies suggest potential links to sleep disruption, possibly through interference with melatonin production. The risk of cancer from these low-level EMFs is largely considered weak by major health organizations, though some concerns and ongoing research exist. Neurological symptoms and impacts on reproductive health have also been explored, with more conclusive evidence regarding heat-related fertility risks from direct laptop use. A significant safety concern identified is the potential for chargers to overheat and cause fires, especially on flammable surfaces. Recommendations from health organizations generally advise minimizing EMF exposure during sleep as a precautionary measure, along with specific tips such as maintaining distance, using airplane mode, and charging devices away from the bed. The report concludes that while current evidence does not confirm significant health risks from EMF exposure from chargers, adopting these practical tips is advisable to ensure a safer sleep environment and mitigate the risk of overheating and fire.

The aim of this three part tutorial is to focus the reader's attention to a new exciting behavior of a particular class of cellular neural networks (CNNs): Turing pattern formation in two-grid coupled CNNs. We first analyze the reduced Chua's circuit as the basic cell for the two-grid coupled CNNs capable of producing Turing patterns. We use a nonstandard normalization

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Most of infrasonic stations from International Monitoring System (IMS) of the Comprehensive Nuclear Test Organization (CTBTO) use absolute infrasound sensors associated with acquisition units dedicated to geophysics. These sensors measure ambient atmospheric pressure over a frequency bandwidth from DC to tens of Hz, including the entire infrasound frequency range. The reference cavity vacuum gives them an intrinsic thermal sensitivity much

Particle accelerators pushed the limits of our knowledge in search of the answers to most fundamental questions about micro-world and our Universe. In these pursuits, accelerators progressed to higher and higher energies and particle beam intensities as well as increasingly smaller and smaller beam sizes. As the result, modern existing and planned energy frontier accelerators demand very tight tolerances on alignment and stability of their elements: magnets, accelerating cavities, vacuum chambers, etc. In this article we describe the instruments developed for and used in such accelerators as Fermilab's Tevatron (FNAL, Batavia, IL USA) and for the studies toward an International Linear Collider (ILC). The instrumentation includes Hydrostatic Level Sensors (HLS) for very low frequency measurements. We present design features of the sensors, outline their technical parameters, describe test and calibration procedures and discuss different regimes of operation. Experimental results of the ground motion measurements with these detectors will be presented in subsequent paper.

Time-frequency representations constitute the main tool for analysis of non-stationary signals arising from environmental systems. Recently, the interest for underwater dispersive channels appears since dispersivity phenomena act at very low frequencies which are well suited for long range underwater communication. In such a case, a main interest is to perform estimation of the impulse response of such channel for processing purposes. In this paper we introduce a time-frequency analysis tool that aims to extract the time-frequency components of the channel impulse response. This technique is based on the adaptive time-frequency filtering whose parameters are defined by a local chirp matching procedure. Tests provided for realistic scenarios illustrate the potential and the benefits of the proposed approach.

Time-frequency representations constitute the main tool for analysis of non-stationary signals arising from environmental systems. Recently, the interest for underwater dispersive channels appears since dispersivity phenomena act at very low frequencies which are well suited for long range underwater communication. In such a case, a main interest is to perform estimation of the impulse response of such channel for processing purposes. In this paper we introduce a time-frequency analysis tool that aims to extract the time-frequency components of the channel impulse response. This technique is based on the adaptive time-frequency filtering whose parameters are defined by a local chirp matching procedure. Tests provided for realistic scenarios illustrate the potential and the benefits of the proposed approach.

The use of a piezoceramic element as an actuator to actively control sound radiation from a thin rectangular panel is experimentally studied. The piezoceramic element is bonded directly to the panel surface and provides control inputs directly to the structure, while the error sensor is a single microphone located in the radiated field. Two cases, corresponding to the resonance of the (1, 1) and (3, 1) panel modes, are considered. The results demonstrate that excellent global attenuation of sound levels of the order of 45 dB is achieved in both cases. Mechanisms of control are discussed.

This work compares simultaneous observations of lightning from two complementary systems. FORTE is a low‐Earth‐orbit satellite carrying radiowave and optical instruments for the study of lightning. The radio receivers aboard FORTE observe very high frequency (VHF) emissions from the air‐breakdown process preceding (and sometimes accompanying) a lightning current. The National Lightning Detection Network (NLDN) is a ground‐based array of sensors in the contiguous United States observing the low‐frequency (LF) and very low frequency (VLF) radiation from vertical currents. Prior to the launch of FORTE in 1997, essentially no work had been done on the statistical correlations between (1) ground‐based LF/VLF and (2) spaced‐based VHF remote sensing of lightning. During a 6‐month campaign in April‐September 1998, FORTE took most of its triggered VHF data over and near the contiguous United States, and NLDN data were specially postprocessed in a loosened‐criterion mode providing enhanced de...

Complex impedance measurements were used to analyze the influence of ultraviolet and ozone gas on the electronic behaviour of ZnO films grown by rf magnetron sputtering. The data show that UV exposure strongly increases the ac conductivity of the film at very low frequencies, and that after ozone exposure it recovers the original value. At high frequencies, however, UV-light exposure it does not change the conductivity but the ozone acts in the sense to decrease it. Two distinct mechanisms, related to two relaxation time distributions are clearly observed: they are superimposed in the virgin sample, but they split forming two semicircles in the z 00 (f) À z 0 (f) diagrams when the samples are treated with UV and/or ozone gas. A combination of the bruggeman effective medium approximation (BEMA) with the random free energy barrier model is used to fit the data and to explain the ac conductivity variation phenomena observed.

We analyse GNSS ionospheric scintillation data recorded in Antarctica to investigate the conditions of the near-Earth environment leading to scintillation scenarios, producing a "scintillation climatology" over a large geomagnetic quiet period. Within this scope we realize maps of scintillation occurrence as a function of the magnetic local time (MLT) and of the altitude adjusted corrected geomagnetic coordinates (AACGM). The maps are realized merging observations of two GISTMs (GPS Ionospheric Scintillation and TEC Monitor) located at Mario Zucchelli Station (74.7°S, 164.1°E) and Concordia Station (75.1°S, 123.2°E) in Antarctica during 2008. The results highlight the possibility to investigate the impact of ionospheric irregularities on the phase and amplitude of GNSS signals, evidencing the cusp/cap and auroral contributions. This works aims to contribute to the development of nowcasting and forecasting tools for GNSS ionospheric scintillation.

A rapid signal-fading event produced by diffractive scintillations was observed around 0123 UT on 8 November 2004 by three closely sited (less than 250 m apart) GPS scintillation receivers in northern Norway. The entire duration of the event was about 10 s and was recorded by all three receivers. Intense, short duration events such as these are not clearly observable in the 1-min scintillation index (S4) because they do not necessarily last for the entire minute. In spite of their short duration they can cause a receiver to lose lock because of their intensity. The geomagnetic conditions were disturbed at this time with the interplanetary magnetic field southward for a period of several hours. Magnetometers from the IMAGE network in Scandinavia showed evidence of a 2000 nT substorm. The GPS measurements are compared with all-sky camera (ASC) data to show that the signal fades can be attributed to the GPS ray paths crossing electron density structures associated with the aurora. The ASC images reveal moving auroral structures at the same time as the GPS signals show movement of the ionospheric regions causing fading. The results indicate that at high latitudes low-elevation GPS signals can suffer sudden fading due to E-region auroral events. This is the first time that a direct connection has been established between the loss of lock on a GPS receiver and diffractive fading caused by auroral precipitation.

On 5 April 2010 a coronal mass ejection produced a traveling solar wind shock front that impacted the Earth's magnetosphere, producing the largest geomagnetic storm of 2010. The storm resulted in a prolonged period of phase scintillation on Global Positioning System signals in Antarctica. The scintillation began in the deep polar cap at South Pole just over 40 min after the shock front impact was recorded by a satellite at the first Lagrangian orbit position. Scintillation activity continued there for many hours. On the second day, significant phase scintillation was observed from an auroral site (81°S) during the postmidnight sector in association with a substorm. Particle data from polar‐orbiting satellites provide indication of electron and ion precipitation into the Antarctic region during the geomagnetic disturbance. Total electron content maps show enhanced electron density being drawn into the polar cap in response to southward turning of the interplanetary magnetic field...

During the International Polar Year (IPY), one area of great interest is co-coordinated, multi-instrument probing of the ionosphere at high latitudes. This region is important not only for the applications that rely upon our understanding of it, but also because it contains the footprints of processes that have their origin in the interplanetary space. Many different techniques are now available for probing the ionosphere, from radar measurements to the analysis of very low frequency (VLF) wave paths. Combining these methods provides the ability to study the ionosphere from high in the F-region to the bottom of the D-layer. Thus, coupling processes from the magnetosphere and to the neutral atmosphere can be considered. An additional dimension is through comparisons of the response of the two polar ionospheres to similar (or the same) geomagnetic activity. With more instruments available at the South Pole inter-hemispheric, studies have become easier to accomplish such that a fuller picture of the global response to Sun-Earth coupling can be painted. This paper presents a review of the current state of knowledge in ionospheric probing. It cannot provide a comprehensive guide of the work to date due to the scale of the topic. Rather it is intended to give an overview of the techniques and recent results from some of the instruments and facilities that are a part of the IPY cluster 63-Heliosphere Impact on Geospace. In this way it is hoped that the reader will gain a flavor of the recent research performed in this area and the potential for continuing collaboration and capabilities during the IPY (2007IPY ( -2009)).

In this paper, a novel MoM-based procedure is developed for efficient treatment of scattering problems over a wide frequency band, including very low frequencies where many of the conventional algorithms often fail. The proposed approach, based on closed-form expressions for the evaluation of the fields radiated by rooftop basis functions, is demonstrated to be universally applicable to conducting and dielectric objects without having to address the singularity issues associated with the conventional MoM approach. Furthermore, an equivalent rooftop type of basis function is introduced for handling curved surfaces. Illustrative examples demostrating the reliability and the efficiency of the described procedures are included.

CTX is a lysogenic filamentous bacteriophage that encodes cholera toxin. Filamentous phages that infect Escherichia coli require both a pilus and the products of tolQRA in order to enter host cells. We have previously shown that toxin-coregulated pilus (TCP), a type IV pilus that is an essential Vibrio cholerae intestinal colonization factor, serves as a receptor for CTX. To test whether CTX also depends upon tol gene products to infect V. cholerae, we identified and inactivated the V. cholerae tolQRAB orthologues. The predicted amino acid sequences of V. cholerae TolQ, TolR, TolA, and TolB showed significant similarity to the corresponding E. coli sequences. V. cholerae strains with insertion mutations in tolQ, tolR, or tolA were reduced in their efficiency of CTX uptake by 4 orders of magnitude, whereas a strain with an insertion mutation in tolB showed no reduction in CTX entry. We could detect CTX infection of TCP ؊ V. cholerae, albeit at very low frequencies. However, strains with mutations in both tcpA and either tolQ, tolR, or tolA were completely resistant to CTX infection. Thus, CTX, like the E. coli filamentous phages, uses both a pilus and TolQRA to enter its host. This suggests that the pathway for filamentous phage entry into cells is conserved between host bacterial species.

CTX is a lysogenic filamentous bacteriophage that encodes cholera toxin. Filamentous phages that infect Escherichia coli require both a pilus and the products of tolQRA in order to enter host cells. We have previously shown that toxin-coregulated pilus (TCP), a type IV pilus that is an essential Vibrio cholerae intestinal colonization factor, serves as a receptor for CTX. To test whether CTX also depends upon tol gene products to infect V. cholerae, we identified and inactivated the V. cholerae tolQRAB orthologues. The predicted amino acid sequences of V. cholerae TolQ, TolR, TolA, and TolB showed significant similarity to the corresponding E. coli sequences. V. cholerae strains with insertion mutations in tolQ, tolR, or tolA were reduced in their efficiency of CTX uptake by 4 orders of magnitude, whereas a strain with an insertion mutation in tolB showed no reduction in CTX entry. We could detect CTX infection of TCP ؊ V. cholerae, albeit at very low frequencies. However, strains with mutations in both tcpA and either tolQ, tolR, or tolA were completely resistant to CTX infection. Thus, CTX, like the E. coli filamentous phages, uses both a pilus and TolQRA to enter its host. This suggests that the pathway for filamentous phage entry into cells is conserved between host bacterial species.

No âmbito da realização da Cartografia Geoambiental da Grande Beira à escala 1/50.000, avaliaram-se alguns problemas ambientais da cidade ao nível da contaminação de águas e solos, os decorrentes da exploração do Porto da Beira e de processos geológicos naturais, dos quais se destacam as intrusões salinas e dinâmica litoral. Este projecto foi desenvolvido na perspectiva do fornecimento de um suporte consistente à implementação de políticas governamentais visando a exploração sustentada de águas subterrâneas e de recursos minerais, e contou com a aplicação de metodologias interdisciplinares que envolveram a análise detalhada de imagens de satélite multiespectrais LANDSAT e ASTER, levantamentos geológicos regionais, campanhas para caracterização hidrogeoquímica de águas subterrâneas, de solos e sedimentos de linhas de água e de canal e, ainda, prospecção geofísica electromagnética no domínio frequência. O presente trabalho pretende demonstrar o contributo desta última para a concretização dos objectivos do projecto no que diz respeito à avaliação do risco de captar água salgada e salobra em poços superficiais de abastecimento comunitário.

A kinetic theory of triggered VLF whistler emissions is given that is capable of predicting from a small scale numerical implementation the observed emission forms, and frequency-time characteristics. The present paper focuses on the theoretical developments and the explanation of the triggering process, complete with a demonstration of the threshold behavior (sometimes known as the dot-dash anomaly) and the generation of specific falling frequency emissions that compare quite favorably to typical observations made in the controlled experiments based in Siple Station, Antarctica. The theory that gives these results is a fully self-consistent nonlinear treatment based on kinetic theory and valid in the asymptotic limit when several trapping periods occur within the interaction region. For a typical set of parameters, I = 4.3, n = 400 cm-3 , and amplitude, BT ~ 1.6 pT, for the input wave magnetic field, one has about seven trapping periods in the triggering signal and would expect good results from the asymptotic limit. In this limit the nonlinear dynamics can be reduced to the determination of the time, r, that the resonant particles are trapped. The nonlinear currents can be expressed in terms of this function, r, by simple integrals over the trapped particles' perpendicular velocities alone. Most of the features of the emission process can be determined analytically and properties, such as the rate of change of frequency, related to magnetospheric parameters. For more quantitative predictions such as amplitude and frequency waveforms, a small numerical code which integrates the nonlinear wave equations is used. The theoretical picture of the triggering mechanism i

Experimental data, which was acquired in two centrifugal pumps and provided by Grundfos A/S, were analysed to determine if rotating stall could be detected from the velocity and pressure time series. The pressure data, which were uniformly acquired in time at high sample rates(10 kHz), were measured simultaneously in four adjacent diffuser channels just downstream of the impeller outlet. The velocity data, which were non-uniformly sampled in time at fairly low rates(100 Hz to 3.5 kHz), were acquired either in or downstream of the impeller. Two different methodologies were employed for detection of stall. The first method, which involved direct analysis of raw data, yielded qualitatively useful flow reversal information from the time series for the radial velocity. The second approach, which was based on power spectrum analysis of velocity and pressure data, could detect the onset and identify the frequency of rotating stall to a satisfactory extent in one of the two pumps. Nearly identical stall frequencies were observed in both velocity and pressure power spectra and this rotating stall phenomenon, which occurred at a very low frequency relative to the impeller speed, did not reveal any noticeable degree of sensitivity to the flow rate. In the other pump, where the available data was limited to velocity time series, the power spectrum analysis was successful in detecting stationary stall for a 6 bladed impeller but did not provide conclusive results for the existence of stall in the case of the 7 bladed impeller. Recommendations on the type of experimental data required for accurate detection of stall are provided based upon the present study.

An international project network consisting of five receivers for sampling LF and VLF radio signals has been going on to record the data in Europe from different transmission stations around the World. One of them was established in Resadiye, Turkey, located just on the North Anatolian Fault Zone. The receiver works in VLF (16.4, 21.75, 37.5 and 45.9 kHz) and LF (153, 180, 183, 216 and 270 kHz) bands monitoring ten frequencies with one minute sampling interval.

While still in its infancy, the budding field of gravitational-wave astronomy has so far exceeded most expectations, and the achievements that have already been made bode well for the decade to come. While the discoveries made possible by LIGO have captured the imagination of experts and nonexperts alike, it is important when looking ahead to consider those discoveries in the context of the field as a whole. Just as radio, optical, and x-ray radiation probe different physical phenomena occurring on a range of length and energy scales, the future of gravitational-wave astrophysics depends on our ability to open up the entire spectrum. We will describe the scientific prospects for the field of gravitational-wave astronomy as a whole as we enter the coming decade, and we will place the specific contributions from a future space-based gravitational-wave observatory within this context.

The spaceborne thermal monitoring of the great eruption of Pu'u 'O'o-Kupaianaha in Hawaii (1987 to present) was attempted, integrating high-resolution SWIR-TIR and lowresolution MIR-TIR observations. Data acquired by multispectral payloads ASTER and MODIS onboard spacecraft Terra, and MODIS onboard Aqua, were processed behind real time by the use of computing routines "MyVOL" and "MyMOD" based on assessed theory and designed for real-time operations. The process was tested against the 2000-2005 eruptive history, both in geometry and volume dynamics of the lava flow. Here, instant lava effusion rates obtained from approximately 1800 cloud-free (over a total > 3000) day-/nighttime MODIS scenes and 12 cloud-free (over a total of 30) nighttime ASTER scenes are compared with each other and with volcanological ground truth composed of gas (SO 2)and electromagnetic potential (very low frequency)-derived eruption rates. Remote-sensed eruption rates are consistent with ground truth from approximately 1 m 3 /s up to the peak effusion rates of 1.2-1.3 million m 3 /day observed in 2005.

New types of variable frequency sinewave oscillators are introduced which bring the most desirable linear tuning laws of the forms fo c Re, and fo oc Ce into the domain of sinusoidal oscillators. Two exemplary circuits are presented and the experimental results are given which are found to be in agreement with the theory. In their various modes of operation, the proposed types of oscillators promise to provide many significant advantages in various instrumentation and measurement applications which are not possible to achieve with previously known active resistance-capacitance (RC) oscillators. R

Complex impedance measurements were used to analyze the influence of ultraviolet and ozone gas on the electronic behaviour of ZnO films grown by rf magnetron sputtering. The data show that UV exposure strongly increases the ac conductivity of the film at very low frequencies, and that after ozone exposure it recovers the original value. At high frequencies, however, UV-light exposure it does not change the conductivity but the ozone acts in the sense to decrease it. Two distinct mechanisms, related to two relaxation time distributions are clearly observed: they are superimposed in the virgin sample, but they split forming two semicircles in the z 00 (f) À z 0 (f) diagrams when the samples are treated with UV and/or ozone gas. A combination of the bruggeman effective medium approximation (BEMA) with the random free energy barrier model is used to fit the data and to explain the ac conductivity variation phenomena observed.

In vitro culture of explants were used to apply genetic or cell enginerring techniques to the sexually incompatible potato relative Solanum commersonii (2n = 2x = 24) Three accessions of S. commersonii were tested for regeneration from leaf explants using six different protocols. A two step-regeneration procedure gave the best results. Genetic variability for regeneration ability was found between accessions, and between clones within accessions. The accession PI 472834 regenerated at highest frequency. Clones with high regeneration ability were selected. Approximately 60% of regenerated plants were diploids and 40% were tetraploids. A very low frequency of chimeras was found. Leaf shape and chloroplast counts in guard cells were shown to be quick and reliable methods for estimating ploidy levels. Use of the diploid and tetraploid regenerants obtained for potato breeding is discussed.

constantly affect the terrestrial atmosphere. Although the effects that phenomena created in different areas produce in atmospheric layers depend on their characteristics and the observed geographical location, changes can very often be detected in large areas that include several atmospheric layers. Also, there are numerous influences on one atmospheric area (Nina et al., 2017; Silber and Price, 2017). In addition, changes in the atmosphere as a medium, in which other processes take place, have an impact on various processes and technologies in modern life (

Microcontroller-based master and slave units are designed with serial ports for communication with a computer and a transmission port to couple the signal to modems at both ends. The programming of the microcontrollers at either end for formatting the data bits before they are sent down the power line and the development of software for putting in place the required master and slave protocols is presented. Coupling data signals to power line through interfacing circuits is a challenging task as power line and the communication system operate at two extremes very lowfrequency and high powerfor the power line while communication is working at very highfrequency and very low voltage and current levels. Hence, the coupling circuit to be designed must be capable to withstand the high power system side in order to prevent a damage being done to the electronic side of the communication system. At the same time it must be reliable enough to make sure that data bits are transferred on to the power line with high accuracy. The interfacing circuits are designed and tuned to frequency contents making the bits of data. The frequency performance of these coupling circuits is presented, showing the range a power line can be used for communication ofsuch data.

This ethological study was carried out to establish the occurrence of psychosis in dogs, reared both in-home (as a pet) and in dog kennels. The dogs housed in kennels were reared either individually (as working animals) or in groups (in kennels). All the pet dogs were reared alone in the households. The highest occurrence of psychotic states was encountered in stray dogs housed in kennels and followed by the pet dogs. These states were very rarely observed in individually reared dogs at farms and working dogs. The possible explanation is that they were submitted to less stressors due to good management at farms and the proper approach on the basis of their temperaments, i.e. their welfare was at the highest level.

Calibration is an activity to determine the conventional truth of the value of the appointment of a measuring instrument by comparing traceable standards to national and international standards for measurement or international units and certified reference materials. The purpose of this study is to develop a system of efficient and practical centrifuge calibrators by sending the calibration results directly via Bluetooth to a PC. The main series of centrifuge calibrators are Arduino modules, laser sensors, and Bluetooth. The high low signal is obtained from the reflection of the laser beam aimed at the reflector point on the centrifuge plate, processed in the Arduino module and displayed on the LCD, the calibration results can be directly seen in the Delphi program. The design of this module is also equipped with a Bluetooth transmitter to send data to a PC. This module can be used in medical equipment calibration laboratories. Based on the results of testing and data collection on the 8 Tube centrifuge with a Lutron Tachometer ratio, the error value was 0.0136%. After planning, experimenting, making modules, testing modules, and collecting data, it can be concluded that the tool "centrifuge calibrator equipped with PC-based data processors" can be used and according to planning because the fault tolerance does not exceed 10%.

Standing Alfvén waves of 1.1 mHz (∼15 min in period) were observed by the Cluster satellites in the mid-tail during 06:00-07:00 UT on 8 August 2003. Pulsations with the same frequency were also observed at several ground stations near Cluster's footpoint. The standing wave properties were determined from the electric and magnetic field measurements of Cluster. Data from the ground magnetometers indicated a latitudinal amplitude and phase structure consistent with the driven field line resonance (FLR) at 1.1 mHz. Simultaneously, quasi-periodic oscillations at different frequencies were observed in the post-midnight/early morning sector by GOES 12 (l 0 ≈8.7), Polar (l 0 ≈11-14) and Geotail (l 0 ≈9.8). The 8 August 2003 event yields rare and interesting datasets. It provides, for the first time, coordinated in situ and ground-based observations of a very low frequency FLR in the mid-tail on stretched field lines.

In this paper, we present the results of sub-ionospheric VLF perturbations observed on NWC (19.8 kHz) ransmitter signal propagating in the Earth-ionosphere waveguide, monitored at Agra (Geomag. Lat 27˚E, long. 78˚N) using SoftPAL receiver. During the period of observation (June, 2011 to December, 2011), we found 75 cases of abrupt amplitude/phase perturbations showing early character. Most of the early events observed show an amplitude change lying between 0.16-4.5 dB, only few cases having >4.5 dB and phase change lying between 01-17 degree respectively. The onset duration of these early perturbations is up to ~ 5 sec, showing early slow character. The World Wide Lightning Location Network (WWLLN) data and the broadband VLF data is analysed to find the location of causative lightning associated with these early VLF perturbations. During the period of our study majority of the events are observed at nighttimes and only few cases are observed at daytimes most likely due to the occurrence of red sprite or elves in the daytime. The lightning discharge and associated processes that leads to the changes in the waveguide characteristics and hence VLF transmission have been discussed. .

The Epstein–Barr virus (EBV) nuclear antigen 1 (EBNA1) is one of the earliest viral proteins expressed after infection and is the only latent protein consistently expressed in viral-associated tumors. EBNA1's crucial role in viral DNA replication, episomal maintenance, and partitioning is well examined whereas its importance for the immortalization process and the tumorgenicity of EBV is unclear. To address these open questions, we generated, based on the maxi-EBV system, an EBNA1-deficient EBV mutant and used this strain to infect primary human B cells. Surprisingly, lymphoblastoid cell lines (LCL) emerged from these experiments, although with very low frequency. These cell lines were indistinguishable from normal LCLs with respect to proliferation and growth conditions. A detailed analysis indicated that the entire viral DNA was integrated into the cellular genome. At least 5 of the 11 latent EBV proteins were expressed, indicating the integrity of the EBV genome. EBNA1-positi...

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The VLF (Very Low Frequency) / LF (Low Frequency) receiving network has been established in Japan, which is composed of seven observing stations (Moshiri (Hokkaido), Chofu (Tokyo, UEC, University of Electro-Communications), Tateyama (Chiba), Shimizu (Shizuoka), Kasugai (Aichi), Maizuru (Kyoto) and Kochi (Kochi)), and three additional foreign stations have been established in Kamchatka, Taiwan and Indonesia. At each station we observe simultaneously several VLF/LF transmitter signals (two Japanese transmitters with call signals fo JJY (Fukushima), JJI (Miyazaki)), and foreign VLF transmitters (NWC (Western Australia, Australia), NPM (Hawaii, USA), NLK (Washington, USA)). This Japanese VLF/LF network is used to study the ionospheric perturbations associated with earthquakes, and we present two recent results; (1) a statistical result on the correlation between VLF/LF propagation anomalies and earthquakes, and (2) the latest results during the last six months on the two particular propagation paths; JJY-Moshiri and JJY-Taiwan. Then, we discuss the correlation of ionospheric perturbations with earthquakes in the sense of a possibility of earthquake prediction by means of VLF propagation anomalies.

The electrical properties of epoxy resin have been studied as a function of hydration. The epoxy was studied in an un-filled state, filled with 40 µm SiO 2 particles, and filled with 50 nm SiO 2 particles. The relative humidity was controlled by saturated salt solutions at ambient temperatures from 298-353 K. Measurements were made using dielectric spectroscopy over the frequency range 10-3-10 5 Hz. The hydration isotherm (i.e. the mass uptake of water) was established by measuring the mass as a function of relative humidity (RH). It was found that the nanocomposites absorb up to 60% more water than the unfilled and micro-filled epoxies. Dielectric spectroscopy shows different conduction and quasi-DC behaviours at very low frequencies (<10-2 Hz) with activation energies dependent on the hydration and temperature. These observations have led to the development of a "water shell" model to explain this phenomenon.

Heart rate variability of seven isolated and five in-vivo rabbit hearts was compared. Heart rate of isolated hearts is lower and RR-intervals longer than those of in-vivo hearts. Characteristic peaks in characteristic frequency bands are different and powers of these bands are almost twice higher in in-vivo hearts than in isolated ones. LF/HF ratio is more than five-times higher in

Whistler-mode waves propagating to ground stations along geomagnetic-ÿeld-aligned paths provide powerful tools for investigating bulk motions of the magnetospheric plasma and thus the corresponding convection electric ÿelds. Natural whistlers from lightning as well as signals from very low frequency (VLF) transmitters have been employed. The whistler method emphasizes measurement of temporal variations in the frequency versus time, or dispersion, properties of whistlers, while the transmitter method focuses upon measurement of the phase and group paths of ÿxed-frequency signal propagation. The methods depend upon wave properties that are sensitive to inhomogeneities in the geomagnetic ÿeld, and thus provide information on what are essentially cross-L plasma motions in a frame of reference rotating with the Earth. In addition, whistler data on the duskside plasmasphere bulge have been used to estimate values of the radial convection electric ÿeld (GSE Y direction) near dusk. In this topical review we discuss the development, beginning in the 1960s, of the whistler and transmitter methods, as well as a few of their geophysical applications. Whistlers have provided substantial new information on the spatially and temporally structured manner in which convection electric ÿelds penetrate the plasmasphere, one example being the still unexplained reversal from inward to outward of the post-midnight radial ow direction following temporally isolated substorms. Whistlers have also been useful in identifying the plasmaspheric drifts associated with quiet-day electric ÿelds of ionospheric dynamo origin and in showing that the Ey (duskward), component of the convection electric ÿeld in the outer plasmasphere is substantially larger near dusk than it is near midnight. Whistler-mode signals from transmitters have been found to be a powerful means of tracking cross-L motions in the plasmasphere near L = 2:5 while separately identifying the e ects of interchange uxes with the ionosphere on the signal phase and group paths.

This paper gives an overview of an empirical crosscalibration technique developed for the Surface Water Ocean Topography mission (SWOT). The method is here used to detect and to mitigate two spatially coherent errors in SWOT topography data: the baseline roll error whose signature is linear across track, and the baseline length error whose signature is quadratic across track. Assuming that topography data are corrupted by coherent error signatures that we can model, we extract the signatures, and we empirically use the error estimates to correct SWOT data. The cross-calibration is tackled with a two-step scheme. The first step is to get local estimates over cross-calibration zones, and the second step is to perform a global interpolation of local error estimates and to mitigate the error everywhere. Three methods are used to get local error estimates: 1) we remove a static first guess reference such as a digital elevation model, 2) we exploit overlapping diamonds between SWOT swaths, and 3) we exploit overlapping segments with traditional pulse-limited altimetry sensors. Then, the along-track propagation is performed taking the local estimates as an input, and an optimal interpolator (1-D objective analysis) constrained with a priori statistical knowledge of the problem. The rationale of this paper is to assume that SWOT's scientific requirements are met on all errors but the ones being cross-calibrated. In other words, the algorithms presented in this paper are not needed at this stage of the mission definition, and they are able to deal with higher error levels (e.g., if hardware constraints are relaxed and replaced by additional ground processing). Even in our most pessimistic theoretical scenarios of baseline roll and baseline length errors (up to 70 cm RMS of uncorrected topography error), the cross-calibration algorithm reduces coherent errors to less than 2 cm (outer edges of the swath). Residual errors are subcentimetric for very low-frequency errors (e.g., orbital revolution). Sensitivity tests highlight the benefits of using additional pulse-limited altimeters and optimal inversion schemes when the problem is more difficult to solve (e.g., wavelengths of less than 1000 km), but also to provide a geographically homogeneous correction that cannot be obtained with SWOT's sampling alone.

Power spectral density is an accepted measure of heart rate variability. Two estimators of multifractal properties: Wavelet Transform Modulus Maxima and Multifractal Detrended Fluctuation Analysis are used to investigate multifractal properties for the three strongly physiologically grounded components of power spectra: low frequency (LF), very low frequency (VLF) and ultra low frequency (ULV). Circadian rhythm changes are examined by discrimination of daily activity from nocturnal rest. Investigations consider normal sinus rhythms of healthy 39 subjects which are grouped in two sets: 5-hour wake series and 5-hour sleep series. Qualitative arguments are provided to conjecture the presence of stochastic persistence in LF range, loss of heart rate variability during night in VLF range and its increase in ULF.

At nanohertz frequencies gravitational waves (GWs) cause variations in time-of-arrival of pulsar signals potentially measurable via precision timing observations. Here we compute very-lowfrequency GW sensitivity constrained by instrumental, propagation, and other noises fundamentally limiting pulsar timing observations. Reaching expected GW signal strengths will require estimation and removal of 99% of time-of-arrival fluctuations caused by typical interstellar plasma turbulence and a reduction of white rms timing noise to ∼100 nsec or less. If these were achieved, single-pulsar signal-to-noise ratio (SNR) = 1 sensitivity is then limited by the best current terrestrial time standards at h rms ∼2 ×10 −16 [f/(1 cycle/year)] −1/2 for f < 3 × 10 −8 Hz, where f is Fourier frequency and a bandwidth of 1cycle/(10 years) is assumed. This sensitivity envelope may be optimistic in that it assumes negligible intrinsic pulsar rotational noise, perfect time transfer from time standard to observatory, and stable pulse profiles. Nonetheless it can be compared to predicted signal levels for a broadband astrophysical GW background from supermassive black hole binaries. Such a background is comparable to time-keeping-noise only for frequencies lower than about 1 cycle/(10 years), indicating that reliable detections will require substantial improvements in signal-to-noise ratio through pulsar array signal processing.

Този доклад представя сравнение между пресмятания на тежки аварии за ВВЕРНЮО реактори с ASTEC код за събитие пълно обезточване с отворен предпазен клапан на компенсатора на обема и без интервенция на хидроакумулаторите. Целта на представения анализ е да представи подобренията на актуализираната версия (ASTEC vl.2 revl) no отношение на ASTEC VI. I p2: промени в кода, подобрения на входни данни. Подобни несъответствия н/е бъдат изучени и, според случая, предложения за подобрения па ASTEC ще бъдат направени.

The problem of constructing millennia-long tree-ring chronologies from overlapping segments of cross-dated ring-width series is reviewed, with an emphasis on preserving very low-frequency signals potentially due to climate. In so doing, a fundamental statistical problem coined the &#39;segment length curse&#39; is introduced. This &#39;curse&#39; is related to the fact that the maximum wavelength of recoverable climatic information is ordinarily related to the lengths of the individual tree-ring series used to construct the millennia-long chronology. Simple experiments with sine waves are used to illustrate this fact. This is followed by more realistic experiments using a long bristlecone pine series that is randomly cut into a number of 1000-, 500- and 200-year segments and standardized using three very conservative methods. When compared against the original, uncut series, the resulting &#39;chronologies&#39; show the effects of segment length even when the most conservative and n...

In our earlier papers we have found the effect of VLF transmitter signal depression over epicenters of the large earthquakes from observation on the French DEME-TER satellite that can be considered as new method of global diagnostics of seismic influence on the ionosphere. At present paper we investigate a possibility VLF signalionospheric turbulence interaction using additional characteristic of VLF signal-spectrum broadening. This characteristic is important for estimation of the interaction type: linear or nonlinear scattering. Our main results are the following:-There are two zones of increased spectrum broadening, which are centered near magnetic latitudes =±10 • and =±40 •. Basing on the previous case study research and ground ionosonde registrations, probably it is evidence of nonlinear (active) scattering of VLF signal on the ionospheric turbulence. However occurrence rate of spectrum broadening in the middle-latitude area is higher than in the near-equatorial zone (∼15-20% in comparison with ∼100% in former area) that is probably coincides with the rate of ionospheric turbulence.-From two years statistics of observation in the selected 3 low-latitude regions and 1 middle-latitude region inside reception area of VLF signal from NWC transmitter we find a correlation of spectrum broadening neither with ion-cyclotron noise (f =150-500 Hz), which

We report on the analysis of ELF/VLF emissions observed by the Instrument Champ Electrique (ICE) experiment onboard the DEMETER micro-satellite. We consider principally selected seismic events reported by . These authors studied the VLF signals radiated by ground transmitters and received on board the DEMETER micro-satellite. They revealed a drop of the signals (scattering spot) connected with the occurrence of large earthquakes. In our investigations, we proceed to a spectral analysis of ICE observations with the aim to find if the natural ionospheric VLF/ELF emissions show, or not, a similar "drop;; in the intensity as it is the case of the VLF transmitter signal. We combine our results with those of Molchanov et al. ( ), and we discuss the origin of such interesting ionospheric features in the frame of the investigation of the pre-seismic electromagnetic emissions. We show that the geomagnetic activity is a key parameter which could disturb the natural VLF ionospheric emissions, and also the transmitter signal. We find that it is not possible to conclude the presence, or not, of a preseismic effect when the Kp-index is higher than one.

The terahertz gap lies between the infrared and millimeter regions of the electromagnetic spectrum. Terahertz (THz) waves, or T-rays, bridge the gap between electronics and photonics, have novel properties and interact uniquely with many materials. Various rotational, vibrational and translational modes of molecules are within the THz range (0.1-10 THz). Since these modes are unique to a particular molecule it is possible to obtain a 'THz fingerprint' allowing for the identification of chemical substances. Astronomers and chemists have already utilised the THz region to characterise and identify small organic molecules. Terahertz spectroscopy allows not only for exploration of molecular structures but also for molecular dynamics. One difficulty in performing THz spectroscopy is that the data can be noisy and thus difficult to interpret. An a priori knowledge of the expected THz spectra allows improved experiments to be performed. Ab initio molecular orbital theory is a helpful tool in providing a great deal of information about intermolecular structure, interactions and dynamics. Recently, we have begun to investigate whether THz is a useful part of the spectrum for studying the photoisomerization of the retinal chromophore by using molecular modelling and vibrational mode calculations. The vibrational character of very low frequency modes can provide insight into molecular dynamics since they potentially relate to the torsional coordinates relevant to the actual isomerization itself. To date, very few studies on the retinal molecule and its isomers based on THz technology have been carried out. Initial experiments using THz Time-Domain Spectroscopy (THz-TDS) have shown that it is possible to distinguish between the different isomeric forms of retinal, indicating that the THz modality may be useful for studying very low frequencies and associated mechanics. In order to motivate further THz experiments on retinal, this paper reviews: (i) the status of the retinal chromophore, (ii) the work in the area uptil now, and (iii) the background of THz spectroscopy-furthermore we review and perform ab initio calculations for all-trans and 9-cis retinal in the THz regime.