Infralow Frequencies Research Articles

Infra-low-frequency gravitational wave signals in the electric and magnetic fields of the earth

Signals with infra-low frequencies corresponding to the frequencies of gravitational-wave radiation from known binary star systems have been detected in the electric and magnetic fields of the Earth. The use of a eigenvector and signal-component analyzer has proved effective in detecting energetically not dominant components in time series of the electric and geomagnetic fields. The amplitude and probability characteristics of these signals are estimated.

Clinical and psychological confirmation of stabilizing effect of neurofeedback in migraine

IntroductionNeurofeedback in migraine aims to improve neurophysiological state, which is linked to psychosomatic, emotional and cognitive regulation. Objective and complex evaluation of neurofeedback effects is feasible.MethodsA single case design cross-over placebo-controlled study with blinded evaluator included 3 females with frequent migraine (N., E., T.), 1 of whom (T.) also had TTH. Study had 4 phases: evaluation (≥ 2 weeks), treatment 1 (5 weeks), treatment 2 (5 weeks), evaluation (≥ 2 weeks). Treatment 1 and 2 included 10 infra-low frequency neurofeedback and 10 sham-neurofeedback sessions at T3T4 site in randomized order. Detailed psychological assessment was performed a baseline, at phase switch and in the end. Every day participants filler a computerized diary about pain, aura, mood, stress, copings. Before each session they received questionnaires “well-being, activity, mood” (rating of the current state between antonym adjectives, in Russian).ResultsThe main finding was reduction of migraine (but not TTH) frequency during real, but not sham neurofeedback phase: 11% vs. 31% days in N. (P = 0.1), 15% vs. 30% days in E. (P = 0.046), T. After the start of neurofeedback had only TTH. Another detected phenomena was reduction of day-to-day shifts in cognitive function domains of “well-being, activity, mood” (easy/difficult to think, attentive/distracted). In N. and E these domains had co-dynamic with mood (good/bad mood, happy/sad), while in T. – with anxiety (tensed/relaxed, nervous/calm).ConclusionInfra-low frequency neurofeedback from interhemispheric site resulted in decrease in migraine frequency and in reduction of shifts in psychological state. Thus, the treatment had multimodal stabilizing effect.Disclosure of interestThe authors have not supplied their declaration of competing interest.

Sham-neurofeedback as an intervention: Placebo or nocebo?

IntroductionSham-controlled studies of neurofeedback are aimed to provide evidence-based data regarding its efficacy. However, a sophisticated sham procedure may turn out to be an intervention rather that a neutral control.MethodsData from a single-case cross-over sham-controlled study of NF in migraine were analyzed to access the effects of sham-NF. The study included 5 females with chronic migraine and was divided into 4 phases: pre-evaluation (≥ 2 weeks), treatment 1 (5 weeks), treatment 2 (5 weeks), post-evaluation (≥ 2 weeks), where treatment 1 and 2 included 10 infra-low frequency NF and 10 sham-NF sessions at T3T4 site in randomized order. Participants filled out a computerized diary about headache and emotions.ResultsSham-NF resulted in some reduction of the level of tension (0.8 ± 0.7 vs. 1.1 ± 0.5, P = 0.1) and anxiety (0.56 ± 0.5 vs. 0.95 ± 0.4, P = 0.07) as measured by the mean value in the diary (rating from 0 - no emotion, to 3 - very intense). While the total frequency of headache was not influenced by sham-NF (40 ± 11% vs. 40 ± 7% days, P = 1), a tendency towards an increase in quantity of severe headaches (42 ± 18% vs. 20 ± 18% days, P = 0.07) and in the need for drug intake (74 ± 27% vs. 44 ± 30% days, P = 0.07) was observed. We supposed that expectation of feedback and failure to receive it during sham sessions may have possible negative effects, while frequent visits to the clinic and contact with the therapist may explain reduction in anxiety.ConclusionSham-NF seems to have both placebo and nocebo effects, which should be considered during interpretation of results of the studies.Disclosure of interestThe authors have not supplied their declaration of competing interest.

Gravitational Wave Track in the Electromagnetic Field of the Earth in the Infra-Low Frequency Range

Signals in the infra-low frequency range in the electric and geomagnetic fields of the Earth have been detected, corresponding to frequencies of gravitational waves (GWs) emitted by a series of binary star systems (BSS). The coherence of the detected signals has been investigated. The amplitude characteristics of signals in the electric and geomagnetic fields at GW frequencies of BSS are estimated. The estimates of the amplitudes of the detected signals are in line with model estimates.

Internal friction in chalcogenide glasses Ge-As-Se system in glass transition region

Purpose. The purpose of this work is detecting and determine of mechanisms of relaxation transitions in chalcogenide glasses Ge-As-Se system based on research of temperature dependences of internal friction, shear modulus over a wide temperature range on infralow frequencies. Methods. The temperature dependences of the internal friction and the shear modulus for glasses in the Ge–As–Se system at infralow frequencies of forced torsional vibrations were measured by torsional pendulum method. Results. For all the glasses under investigation, the mechanical losses rapidly increase and, simultaneously, the shear modulus decreases in the range of the glass transition temperature T g . With an increase in the strain frequency, these effects shift toward the high_temperature range, which indicate that the intensive relaxation process proceeds in this temperature range. The parameters U α and τ 0 of this relaxation process were determined from the frequency shift in the hightemperature branch Q –1 ( T ). Conclusions. An increase in the internal friction and the mechanical compliance of glasses in the Ge–As–Se system in the range of the glass transition temperature T g is caused by the activation of the α relaxation process. At Z =2.6, the activation energy of this process increases considerably as a result of the change in the kinetic structural unit responsible for the relaxation process under consideration. α relaxation process occurs as a result of the full defreezing of the mobility of glass structure in T g region.

Observed flow variability along the thalweg, and on the coastal slopes of the Gulf of Finland, Baltic Sea

Bottom-mounted ADCP measurements from 10 installations, collected between 2009 and 2014 and each lasting several months, are analysed in order to distinguish between different flow regimes, and to detect variability (a) along the thalweg of the elongated basin, with different regimes in summer and in winter, and (b) on the coastal slopes. In the deep thalweg area the mean flow speed amounts to 6–13 cm s−1, whereas the maximum speeds appear in winter near the bottom of the basin, and in summer within the halocline (around 70 m depth). The mean zonal flow component reveals a nearly depth uniform inflow during winter, and a layered inflow-outflow during summer. In years where up-estuary (W to SW) winds are stronger during the summer, inflow dominates in upper layers, and anti-estuarine outflow dominates in deeper layers. This causes the export of a salt wedge, and the weakening of haline stratification. Infra-low frequency zonal currents (i.e. excluding topographic waves etc. with periods of less than 10 days) have a structure which is uniform with depth for 53% of the time in winter; in summer, a layered structure is present 65% of the time. However, during both periods the reversed estuarine flow (inflow in upper layers and outflow in the bottom layer) appears, on average, for 30% of the time. The deep flow zonal component is well correlated with westward winds during summer (r = 0.84), and south-westward winds during winter (r = 0.77). On the coastal slopes, the speed of the currents are lower than in the thalweg region, and they decay with depth. In the vertical the flow exhibits a layered structure in both the winter and summer seasons.

Dielectric properties of (K0.5Na0.5)(Nb0.93Sb0.07)O3 ferroelectric ceramics modified with BaTiO3

Processes of the polarization and repolarization of ferroelectric ceramics based on potassium sodium niobate in the region of infralow frequencies are discussed. The effect aging and subsequent annealing in a strong alternating electric field have on the nonlinearity of the dielectric response of a sample at different temperatures is determined.

Mechanical properties measurement of solids at infralow frequencies

Описано автоматизовану установку, яка дозволяє досліджувати модуль зсуву та інфранизькочастотне внутрішнє тертя (ВТ) з використанням оберненого крутильного маятника в режимі вільнозгасаючих або вимушених коливань на частотах 10 -3 − 20 Гц в інтервалі відносної деформації 10 −6 – 10 −2 та діапазоні температур 100− 600 K.

Enhancing anti-tumor effect of magnetite nanoparticles using weak electromagnetic radiation of infra-low frequencies in experiment.

e23198Background: Activating influence of weak electromagnetic radiation of infra-low frequencies (WER ILF) used in special regimes on systemic antitumor mechanisms was shown. Effectiveness of thes...

Interdisciplinary rehabilitation of a patient with right brain injury and recurrent depression

IntroductionRehabilitaton of concurrent psychiatric disorder and brain injury is a major challenge. E. underwent neurosurgery for right fronto-parietal astrocytoma. Before illness he was managing automatization of big companies, but was fired after the operation. E. felt into severe depression and anxiety with catastrofization of his illness, suicidal ideation. He resisted multiple prescriptions for SSRI, admitting a sect pretending to “treat” oncology by “psychological” methods. Half a year after operation he attended our center.Objectives and aimTo help E. return to paid employment.MethodsE. was evaluated by neurologists, psychiatrist, neuropsychologists. Current depressive episode appeared to be the second one with underlying schizoid and perfectionist characteristics. He had moderate text comprehension difficulties, confabulations, slight executive dysfunction. Neuropsychologist educated patient on his difficulties and developed compensatory strategies – an alternative to catastrofisation. After psychoeducational session E. agreed to receive fluvoxamine. However, he deformed the received information due to brain injury, so psychotherapy had only minor effects. Infra-low frequency neurofeedback at T4P4 and T4Fp2 sites was started to promote restoration of right brain functions. E. gradually did better, and 3 months later was able to complete CBT course along with relaxation training.ResultsImprovements in emotional status along with ability to cope with cognitive difficulties allowed E. to return to a job similar to the previous. Six month after the start of treatment medications are tapered off, E. has no signs of depression and only slight anxiety.ConclusionsInterdisciplinary holistic rehabilitation may be effective in concurrent psychiatric disorder and brain injury.Disclosure of interestThe authors have not supplied their declaration of competing interest.

Helicopter vibration isolation: Design approach and test results

This paper presents a strategy based on the approach of designing and inserting into helicopter vibration isolation systems mountable mechanisms with springs of adjustable sign-changing stiffness for system stiffness control. A procedure to extend the effective area of stiffness control is presented; a set of parameters for sensitivity analysis and practical mechanism design is formulated. The validity and flexibility of the approach are illustrated by application to crewmen seat suspensions and vibration isolators for equipment protection containers. The strategy provides minimization of vibrations, especially in the infra-low frequency range which is the most important for crewmen efficiency and safety of the equipment. This also would prevent performance degradation of some operating systems. The effectiveness is demonstrated through measured data obtained from development and parallel flight tests of new and operating systems.

USE OF AN INFRA-LOW FREQUENCY EEG BIOLOGICAL FEEDBACK TECHNIQUE IN THE COMPREHENSIVE REHABILITATION OF PATIENTS WITH A DECREASED LEVEL OF CONSCIOUSNESS

A protocol for EEG biological feedback (BFB) at infra-low frequencies (<0.01 Hz) corresponding to those of the brain default mode network has been devised in recent years. Objective: to evaluate the therapeutic features of an EEG BFB technique in the rehabilitation of patients with a decreased level of consciousness. Patients and methods. The study included 11 patients with a decreased consciousness level (Glasgow coma scores of 7.4±2.5). The patients were examined using the specialized clinical scales before and every 3 weeks during BFB therapy (5 BFB sessions per week). Results. According to the neuropsychological scales, the patients' level of consciousness and mental activity were noted to become obviously increased just after 3 weeks of therapy, which was observed until the neurorehabilitation course was completed. Conclusion. The minimally conscious patients using EEG BFB showed a significant clinical improvement. The infra-low frequency EEG BFB method deserves attention as a promising tool for increasing the patients' level of consciousness in accessible form.

Application of the Superslow Relaxation Model in the Description of Time Series of the Vertical Electric Field Component in the Earth’s Atmospheric Boundary Layer in the Infra-Low Frequency Range

To explain the presence of spectrally localized, mutually uncorrelated the electric field components in the Earth’s atmospheric boundary layer in the infra-low frequency range, it is proposed to use the model of fractionally integrated white Gaussian noise. It is shown that the uncorrelated components of the fractionally integrated (of order 0.5) white Gaussian noise have a coherence index close to that of the uncorrelated components of time series of the electric field. The energy distribution of the uncorrelated components of the fractionally integrated noise is also close to the energy distribution of the components of the electric field. To lay the basis for a physical interpretation of fractionally integrated noise, it is proposed to use the differential equation of superslow relaxation.

An impedance analyzer of semiconductor structures in the infra-low frequency range

An impedance analyzer of semiconductor structures at infralow frequencies is designed. The analyzer contains a remote measuring head placed near the studied structure and an electronic unit connected to the computer via a USB interface. The analyzer measures the capacitance, conductivity, and current of a structure in a frequency range of 0.01–10 Hz. The measurement ranges of the capacitance value are 10, 100, and 1000 pF, of the current—25, 250, and 2500 pA, and of the conductivity—10, 100, and 1000 pS.

Photoelectric Current and Dielectric Properties of Barium-Strontium Niobate Ceramics under UV and Visible Irradiation

A study of photocurrent kinetics and dielectric response to infra-low frequencies in the range of the broad phase transition in the Ba0.25Sr0.75Nb2O6 (BSN-75) relaxor ceramics under visible and ultraviolet radiation is reported. Anomalies are revealed in the dependence on field intensity of dielectric permittivity and dielectric loss determined from measurements of polarisation loops before and after illumination. The effects of pyro-electric space charge, polarisation and photovoltaic contributions on behaviour of the measured photocurrent are discussed. Results of the kinetics of photocurrent and dielectric response to infra-low frequency studied at different temperatures are discussed as the effects of non-equilibrium carriers on relaxation of polarisation. Kinetics of the photocurrent in ceramics and single crystals is found to be similar.

Non-Debye relaxation and resonance phenomena in dielectric spectra of CaCu3Ti4O12 family functional ceramic materials

Experimental data on dielectric spectra of calcium copper titanate, CaCu 3 Ti 4 O 12 (CCTO) family functional ceramics have been studied and analyzed. It is shown that there are both non-Debye relaxation and resonance regions in their spectra. An occurrence of a retardation of complex permittivity and a relaxation of electric modulus is established. An average relaxation frequency of the electric modulus is considerably (in some cases several orders of magnitude) larger than the retardation frequency of the permittivity. A parallel connection of the capacity and complex conductivity is used to model and interpret experimental data on a negative permittivity in the infralow frequency range. Computer simulation enables us to reveal that the hopping conductivity, characteristic for disordered heterogeneous systems, is to be taken into account to describe adequately experimental data on passing the real part of the capacity (or permittivity) through zero. We have found a critical frequency at which the parallel resonance would take place.

Infra-low Frequency Transcranial Magnetic Stimulation Effectively Improves the Motor Function in Children with Spastic Cerebral Palsy

Background: Cerebral palsy (CP) is one of the major diseases that lead to severe disability and seriously impacts the quality of life of children. Infra-low frequency transcranial magnetic stimulation (ILF-TMS) is a new technique of noninvasive brain stimulation that exactly regulates the power of specific neurotransmitters through a special magnetic field. Our study was in order to investigate the efficacy of ILF-TMS treatment in children with spastic cerebral palsy. Methods: 113 spastic cerebral palsic children were randomly divided into two groups: conventional rehabilitation group and ILF-TMS treatment group, Healthy control group was established at the same time. In conventional rehabilitaion group, children were treated with conventional rehabilitation treatment; In ILF-TMS treatment group were treated with ILF-TMS in addition to conventional rehabilitation treatment. Neurotransmitter in the brain was recorded with encephalofluctuograph (EFG) before and after ILF-TMS treatment. Gross Motor Function Measure (GMFM), Fine Motor Function Measure (FMFM) and Gesell development scale (GDS) were used to comprehensively evaluate the motor function in children with spastic cerebral palsy. Results: The results showed that the relative power of γ-aminobutyric acid (GABA) in spastic cerebral palsy was lower than that in healthy controls and was increased significantly after ILF-TMS treatment for 3 months. The relative power of glutamate (Glu) in spastic cerebral palsy was higher than that in healthy controls and was reduced significantly after ILF-TMS treatment for 3 months. After 3 months training period there was significant improvements on the GMFM (dimension B, dimension C and dimension D), FMFM (dimension A and dimension B) and GDS (gross motor DA and gross motor DQ) in the ILF-TMS treatment group when compared to conventional rehabilitation group. Conclusions: These findings indicate that GMFM is a sensitive indicator to assess the treatment efficacy in children with spastic cerebral palsy and ILF-TMS treatment can improve the motor function through regulating neurotransmitters in brain.

Dielectric Properties of PMN-PNN+2%Li2O Ferroelectric Ceramics at Low and Infra-Low Frequencies

A study of dielectric response to weak and strong measuring fields at temperatures of the diffuse phase transition in lead-magnesium niobate—lead-nickel niobate (PMN-PNN) containing an admixture of lithium is reported. A relaxor behaviour of the ceramic compound manifesting itself by a substantial shift of the temperature of dielectric permittivity maximum with field intensity and frequency is detected. Specific features of the dielectric nonlinearity observed at temperatures considerably higher than the temperature of the low-frequency dielectric permittivity maximum are related to extension of the range of phase transition to higher temperatures. This extension is related to formation of nano-size polar clusters within the region of the diffuse phase transition, the cluster formation being substantially affected by the applied field.

Photoelectrical Properties of the SBN Relaxor Ceramics in the Range of the Broad Phase Transition

A study of the effects of white light on photocurrent kinetics and the low and infra-low frequency relaxation of polarization in the barium-strontium niobate SBN‑75 ceramics is reported. It is found that at a low intensity illumination in the range of the relaxor phase the space charge is mainly responsible for manifestation of photo-electrical properties of SBN-75 ceramics.

Infra-slow Fluctuation Training in Clinical Practice: A Technical History

Infra-slow Fluctuation (ISF) electroencephalogram (EEG) biofeedback is a recent development in neurofeedback training. This form of training is focused on the lowest energy the brain produces (< 0.1 Hz). The intervention is performed with a Direct Current (DC) coupled neurofeedback amplifier. It is distinct from Slow Cortical Potential (SCP) training and Infra-Low Frequency (ILF) training. It shares a similar optimization process with ILF that focuses on emergent state shifts within sessions. These state shifts require frequency adjustments that optimize client response to the training in real time. Due to the technical difficulties inherent in recording these frequencies, EEG investigators largely neglected this low energy until recently. As DC amplifiers improved, the slow frequencies became a signal of increasing interest to researchers. Research has demonstrated an important role for the infra-slow oscillations in clinical work. Positive clinical case outcomes suggest that a larger controlled study is warranted. The technical, clinical, and equipment requirements of the intervention make this form of neurofeedback unique in the pantheon of EEG biofeedback interventions.