Amplitude Delta Research Articles

Seizure detection in EEG signal using Gaussian-stockwell transform and Hermite polynomial features

Electroencephalography (EEG) is a non-intrusive and powerful tool for understanding the complex nature of the brain. Epileptic seizures, a neurological disorder, are characterized by excessively synchronized neuronal activity within the brain. This abnormal synchronization disrupts the normal functioning of neural networks, leading to seizures. This work proposes to use the Gaussian-based Stockwell Transform (GST) to segment EEG signals into various frequency bands such as delta, theta, alpha, beta, and gamma band for analysis. The feature extraction process on these sub-band signals generates a feature set, encompassing the fluctuation index, relative amplitude, holoentropy, logarithmic band power, and the newly introduced Hermite polynomial-based delta amplitude modulation spectrogram. To differentiate between epileptic and non-epileptic events in EEG signals, the previous features have been applied to the Random Forest Classifier (RFC) algorithm. The effectiveness of our proposed method is validated using a benchmark EEG dataset, with GST and RFC demonstrating accurate results in distinguishing seizure activity. Experimental results show an optimal classification accuracy of 96.4 %, a sensitivity of 97 %, and a specificity of 96.4 %.

Exact solutions, wave dynamics and conservation laws of a generalized geophysical Korteweg de Vries equation in ocean physics using Lie symmetry analysis

An evolution equation is a partial diferential equation that describes the time evolution of a physical system starting from given initial data. Evolution equations arise from many areas of applied and engineering sciences. To this end, this article investigates the analytical studies of a generalized geophysical Korteweg-de Vries equation in ocean physics. The examination of this model is conducted via the Lie group theory of diferential equations. In the first place, point symmetries, which are constituent elements of a four-dimensional Lie algebra, are systematically computed. Thereafter, one-parameter transformation groups for the algebra are calculated. Besides, going forward, a one-dimensional optimal system of subalgebras is derived in a procedural manner. Sequel to this, the subalgebras and combination of the achieved symmetries are invoked in the reduction proces which enables the derivation of nonlinear ordinary diferential equations associated with the generalized geophysical Korteweg-de Vries equation under study. Most of the achieved nonlinear ordinary diferential equations are further solved either via direct integration or using a power series approach. Furthermore, travelling wave solutions are initially obtained. This is attained via direct integration and the use of Jacobi elliptic function approach. These techniques enable the attainment of various exact soliton solutions, including non-topological soliton solutions as well as general periodic function solutions of note, such as cosine amplitude, sine amplitude, and delta amplitude solutions of the model. Furthermore, numerical simulations of the solutions are invoked to gain a gross knowledge of the physical phenomena represented by the under-study generalized geophysical Korteweg-de Vries equation in ocean physics. In the end, the investigation further gives attention to the calculation of conserved vectors for the model using Ibragimov's theorem for conservation laws, as well as Noether's theorem.

Effects of CPAP treatment on electroencephalographic activity in patients with obstructive sleep apnea syndrome during deep sleep: Preliminary findings of a cross-sectional study.

Study objectives: To investigate whether electroencephalographic (EEG) activities during non-rapid eye movement sleep stage 3 (N3) in obstructive sleep apnea syndrome (OSAS) patients were changed with continuous positive airway pressure (CPAP) treatment.Methods: A cross-sectional study of EEG activity during N3 sleep was conducted in 15 patients with moderate to severe OSAS without and with CPAP treatment compared to 15 normal controls. The amplitude, and absolute and relative power of delta, theta, alpha and beta waves as well as the absolute power ratio of slow to fast EEG waves (i.e., absolute power of delta and theta waves/absolute power of alpha and beta waves) and the spectral power density of 0-30Hz EEG activities were analyzed.Results: CPAP significantly increased N3 sleep, the absolute and relative powers, amplitudes of delta and theta waves, and absolute power ratio of slow to fast EEG waves, but decreased relative alpha and beta powers during N3 sleep. However, there were no significant differences in those parameters between the OSAS patients with CPAP treatment and normal controls.Conclusions: CPAP prolongs N3 sleep and increases the power and amplitude of slow EEG waves during N3 sleep, which indicates an improvement in sleep quality and further provides evidence for recommendation of CPAP treatment for OSAS patients.

Preliminary Development of a Brainwave Model for K1 Kickboxers Using Quantitative Electroencephalography (QEEG) with Open Eyes.

K1 kickboxing fighting is characterised by high injury rates due to the low restrictions of fighting rules. In recent years, much attention has been paid to research on changes in brain function among athletes, including those in combat sports. One of the tools that are likely to help diagnose and assess brain function is quantitative electroencephalography (QEEG). Therefore, the aim of the present study was an attempt to develop a brainwave model using quantitative electroencephalography in competitive K1 kickboxers. A total of thirty-six male individuals were purposefully selected and then comparatively divided into two groups. The first group consisted of specialised K1 kickboxing athletes exhibiting a high level of sports performance (experimental group, n = 18, mean age: 29.83 ± 3.43), while the second group comprised healthy individuals not training competitively (control group, n = 18, mean age: 26.72 ± 1.77). Body composition assessment was performed in all participants before the main measurement process. Measurements were taken for kickboxers during the de-training period, after the sports competition phase. Quantitative electroencephalography of Delta, Theta, Alpha, sensimotor rhytm (SMR), Beta1 and Beta2 waves was performed using electrodes placed on nine measurement points (frontal: FzF3F4, central: CzC3C4, and parietal: PzP3P4) with open eyes. In the course of the analyses, it was found that the level of brain activity among the study population significantly differentiated the K1 formula competitors compared with the reference standards and the control group in selected measurement areas. For kickboxers, all results of the Delta amplitude activity in the area of the frontal lobe were significantly above the normative values for this wave. The highest value was recorded for the average value of the F3 electrode (left frontal lobe), exceeding the norm by 95.65%, for F4 by 74.45% and Fz by 50.6%, respectively. In addition, the Alpha wave standard value for the F4 electrode was exceeded by 14.6%. Normative values were found for the remaining wave amplitudes. Statistically significant differentiation of results, with a strong effect (d = 1.52-8.41), was shown for the activity of Delta waves of the frontal area and the central part of the parietal area (Fz,F3,F4,Cz-p < 0.001), Theta for the frontal area as well as the central and left parietal lobes (Fz,F3,F4-p < 0.001, Cz-p = 0.001, C3-p = 0.018; d = 1.05-3.18), Alpha for the frontal, parietal and occipital areas (for: Fz,F3-p < 0.001, F4-p = 0.036, Cz-p < 0.001, C3-p = 0.001, C4-p = 0.025, Pz-p = 0.010, P3-p < 0.001, P4-p = 0.038; d = 0.90-1.66), SMR for the central parietal and left occipital lobes (Cz-p = 0.043; d = 0.69, P3-p < 0.001; d = 1.62), Beta for the frontal area, occipital and central lobes and left parietal segment (Fz,F3-p < 0.001, F4-p = 0.008, Cz, C3, Pz, P3,P4-p < 0.001; d = 1.27-2.85) and Beta 2 for all measurement areas (Fz, F3, F4, Cz, C3, C4, Pz, P3, P4-p < 0.001; d = 1.90-3.35) among the study groups. Significantly higher results were shown in the kickboxer group compared to the control. In addition to problems with concentration or over-stimulation of neural structures, high Delta waves, with elevated Alpha, Theta and Beta 2 waves, can cause disorders in the limbic system and problems in the cerebral cortex.

THE EFFECT OF PYRIMIDINE AND CAVINTON DERIVATIVES ON THE CHANGE BIOELECTRIC POTENTIAL IN THE CONDITIONS OF FOCAL CEREBRAL ISCHEMIA OF THE RAT BRAIN

Acute disorders of cerebral hemodynamics lead to the development of socially and demographically significant diseases, as a result of which they are one of the main health problems requiring a rational pharmacological approach. In the pathogenesis of pathologies of cerebral circulation, in addition to a decrease in blood flow, an important role is played by a violation of the bioelectric activity of brain tissues, which is evidenced by changes in the frequency and amplitude of oscillations on the encephalogram. Pyrimidine derivatives have proven themselves as potential cerebroprotectors, as a result of which we considered them as means capable of correcting electroencephalogram disorders in ischemic brain tissues. In this regard, the purpose of this work was to study the effect of pyrimidine and cavinton derivatives on the change in bioelectric potential under conditions of focal central ischemia in rats. Materials and methods. The study was conducted on 40 male rats of the Wistar line (m = 220–220 g). Focal cerebral ischemia of rats was reproduced by occlusion of the left middle cerebral artery. The animals were divided into 4 equal groups, all groups, except the first, were simulated pathology under chloral hydrate anesthesia (350 mg/kg). The first group – falsely operated rats, the second – individuals of negative control. The reference drug cavinton (3.2 mg/kg) and the pi-rimidine derivative PIR-10 (50 mg/kg) were administered to the third and fourth groups within 3 days after surgery. The electrical activity of the rat brain (delta-, theta-, alpha-, high-frequency beta-range in the frontal and parietal lobes of the left hemisphere) was evaluated after 3 days by electroencephalography (EEG) using the Neuron-Spectrum 1 encephalograph (Neurosoft, Russia). Statistical processing was carried out using the STATISTICA 8.0 application software package (StatSoft, Inc., USA). Results of the study. In the rats of the negative control group, there was a marked deterioration in bioelectric potential, which was noted in an increase in theta and delta rhythms and a decrease in alpha and high-frequency beta rhythms. The introduction of the compound PIR-10 to animals contributed to a decrease in delta rhythm by 39,8% (p &lt; 0,05) (FP1-A1) and 56,3% (p &lt; 0,05) (C3-A1), theta rhythm – by 23,9% (p &lt; 0,05) (FP1-A1) and 39,4% (p &lt; 0,05) (C3-A1), the amplitude of the alpha rhythm increased by 75,3% (p &lt; 0,05) (C3-A1), the high-frequency beta rhythm by 25,9% (p&lt;0,05) (FP1-A1) and 41,4% (p &lt; 0,05) (C3-A1). Findings. The experimental derivative of pyrimidine PIR-10, equally with cavinton, contributed to the restoration of bioelectric rhythm in the form of a decrease in the amplitude of delta and theta rhythms and an increase in the amplitude of alpha and high-frequency beta rhythms in the frontal and parietal regions of the left hemisphere of the rat brain.

Detection of neuronal OFF periods as low amplitude neural activity segments

BackgroundDuring non-rapid eye movement sleep (NREM), alternating periods of synchronised high (ON period) and low (OFF period) neuronal activity are associated with high amplitude delta band (0.5–4 Hz) oscillations in neocortical electrophysiological signals termed slow waves. As this oscillation is dependent crucially on hyperpolarisation of cortical cells, there is an interest in understanding how neuronal silencing during OFF periods leads to the generation of slow waves and whether this relationship changes between cortical layers. A formal, widely adopted definition of OFF periods is absent, complicating their detection. Here, we grouped segments of high frequency neural activity containing spikes, recorded as multiunit activity from the neocortex of freely behaving mice, on the basis of amplitude and asked whether the population of low amplitude (LA) segments displayed the expected characteristics of OFF periods.ResultsAverage LA segment length was comparable to previous reports for OFF periods but varied considerably, from as short as 8 ms to > 1 s. LA segments were longer and occurred more frequently in NREM but shorter LA segments also occurred in half of rapid eye movement sleep (REM) epochs and occasionally during wakefulness. LA segments in all states were associated with a local field potential (LFP) slow wave that increased in amplitude with LA segment duration. We found that LA segments > 50 ms displayed a homeostatic rebound in incidence following sleep deprivation whereas short LA segments (< 50 ms) did not. The temporal organisation of LA segments was more coherent between channels located at a similar cortical depth.ConclusionWe corroborate previous studies showing neural activity signals contain uniquely identifiable periods of low amplitude with distinct characteristics from the surrounding signal known as OFF periods and attribute the new characteristics of vigilance-state-dependent duration and duration-dependent homeostatic response to this phenomenon. This suggests that ON/OFF periods are currently underdefined and that their appearance is less binary than previously considered, instead representing a continuum.

Drivers’ Workload Electroencephalogram Characteristics in Cognitive Tasks Based on Improved Multiscale Sample Entropy

Cognitive workload is an internal factor that can be influenced by external factors. When drivers are distracted by these internal and external influences, their ability to drive safely can be compromised. Electroencephalogram (EEG) is a non-invasive neuroimaging technique that measures the electrical activity of the brain. and it can provide information about brain activity related to various cognitive and motor functions. In this study, on-road driving experiments were conducted to investigate the EEG characteristics of drivers under different levels of cognitive workload generated through mathematical calculations with varying difficulties. The collected EEG signals were processed using continuous wavelet transform to decompose them into delta, theta, alpha, beta, and gamma waveforms. Numerical values and power spectral characteristics of each waveband in the left and right frontal regions of the driver were then analyzed. Furthermore, the study utilized an improved multiscale sample entropy algorithm to analyze the EEG entropy characteristics of drivers in different states. The results indicate that under different degrees of cognitive workload, the amplitude of delta, theta, and alpha waves decreased, while beta and gamma waves showed significant changes. The improved multiscale sample entropy algorithm provided a more objective assessment of changes in entropy across different wavebands and stages, with smaller entropy fluctuation ranges and more accurate complexity changes. Overall, this research provides valuable insights into the characteristics of drivers under cognitive workload, contributing to the analysis of human factors in driving safety. These findings can inform the development of strategies to mitigate the adverse effects of cognitive workload on driving performance and enhance overall road safety.

The Photometric Analysis and Classification of High Amplitude δ Scuti: AE Ursae Majoris

AE UMa, a Population I high amplitude Delta Scuti (HADS), was observed for 4 nights through 14-21 March 2022. 454 Visual CMOS observations and 11 new times of maxima were obtained over a period of ~19.4 hours in total. Using python coding and Fourier analysis, a fundamental frequency ƒ0 = 11.6251 cd-1 was established and further observation of amplitudes of light maxima led to beat phenomenon period Pb = 0.29360 d. Subsequently, the first overtone frequency ƒ1 = 15.0316 cd-1 was calculated and the period ratio = 0.7734 was found to be relatively unchanged from Szeidl (1974). Thereafter, the period ratio-metallicity correlation determined by Hintz et al. (1997b) was used to estimate the metallicity [Fe/H] of AE UMa. I concluded that AE UMa is incorrectly classified as a Pop. II HADS (SX Phoenicis) and should be grouped with Pop. I HADS.

Comparative Analysis of Voice Quality on iLBC and Speex Codecs Server PBX with Voice Comparison Method

VoIP servers provide several types of codecs including iLBC and Speex codecs, each type of codec has a different capacity and quality- different. So that in the process of choosing a codec implementation, VoIP becomes one of the things that affect the quality of communication. The iLBC and Speex codecs are intended for high quality but bitrate . By comparing iLBC and Speex communication, VoIP hoped that the better performance between the two codecs would communicate VoIP based on Quality of Service (QoS) and analyze the audio results of VoIP for voice quality analysis using the voice comparison method using Matlab. Based on the results of the research between the iLBC and Speex parameter value QoS including delay codec speex is smaller than iLBC codec of 31.12 ms. The jitter value of the iLBC and speex is the same, namely 0.01. The packet loss value of the iLBC codec is smaller than the speex codec of 6.18%. The results of the sound quality test in matlab using the sound comparison method showed that the delta amplitude codec speex value was smaller than iLBC codec of 0.00004551 volts.

The diagnostic value of the pulsatility curve to predict shunt responsiveness in patients with idiopathic normal pressure hydrocephalus

ObjectiveThe aim of this study was to investigate the diagnostic accuracy of the pulsatility curve to predict shunt response in patients with idiopathic normal pressure hydrocephalus (iNPH).MethodsLumbar cerebrospinal fluid dynamics were derived from an automatic lumbar infusion test (LIT) protocol. All patients were treated with ventriculoperitoneal shunting and re-examined 6 months after shunting. Patient demographics and outcomes were gathered in a prospective, electronic database that spanned from January 2012 to January 2020. A validated iNPH scale was used to assess patients preoperatively and 6 months postoperatively. The relationship of the relative pulse pressure coefficient (RPPC), delta amplitude, successful lowering of amplitude, and the pressure-value at a hypothetical amplitude of zero (P0), resistance to outflow (Rout), and outcome, were assessed using receiver operating characteristic (ROC) curves.ResultsWe included 38 patients. The RPPC, delta amplitude, successful lowering of amplitude, and P0 parameters did not predict shunt response. Mean P0 was 0.5 (IQR 0.4–0.9) in improved patients and 0.4 (IQR 0–1.2) in non-improved patients. The delta amplitude was 0.16 kPa (IQR 0.10–0.23) in improved patients and 0.18 kPa (IQR 0.11–0.24) in non-improved patients. Furthermore, we found a technical failure rate of pulsatility curve measurements of 32%.ConclusionPulsatility curve results were not suitable in predicting shunt response in our cohort. The diagnostic value of LIT in case of normal pressure hydrocephalus should be subject to more rigorous research.

A rational study on the hydrothermal aging of AFP manufactured CF/polyetherketoneketone composites with in situ consolidation supported by acoustic emission inspection

AbstractIn this study, carbon fiber (CF)/polyetherketoneketone (PEKK) composites with 5% void content, manufactured via an in situ consolidated automated fiber placement (AFP) lay‐up process, are aged in hot water at 70°C for 30 days. Firstly, a deep understanding of the deterioration in the mechanical performance is developed with a comprehensive and complementary set of material characterization strategies, including (i) microstructural characterization with Fourier‐transform infrared spectroscopy (FTIR), (ii) thermal characterization with differential scanning calorimetry (DSC), and (iii) dynamic mechanical analysis (DMA). The material characterization concurrently highlights the plasticization and post‐crystallization phenomena after aging with changes in the peak densities with FTIR, formation of second glass transition temperature (Tg) in DSC and DMA, and drop in storage modulus, loss modulus, and tan delta (δ) amplitudes. Then, acoustic emission (AE) is utilized as an inspection tool to identify the damage mechanisms regarding the 6.5%, 5.2%, and 4% decrease in tensile strength, strain at failure and modulus, respectively, in a comparative manner. The AE findings, remarking the weakening of the fiber–matrix interface after aging, are validated with scanning electron microscopy analysis. This study introduces an aging process‐induced damage mechanism triggered with inhomogeneous water absorption for AFP manufactured CF/PEKK composites with in situ consolidation.

High amplitude delta rhythm related cataplexy in a boy with Niemann-Pick type C disease

• Cataplexy can be the only clinical manifestation in the early stage of NPC disease. • The electrophysiological feature of cataplexy is different between NPC and idiopathic narcolepsy. • High amplitude delta pattern correlates of cataplexy indicated the involvement of cortico-thalamo-cortical feedback loops. • Electrophysiological monitoring is of great significance to better understand the pathophysiology of cataplexy.

Management of toxic optic neuropathy via a combination of Wharton\u2019s jelly-derived mesenchymal stem cells with electromagnetic stimulation

PurposeTo investigate the effect of the combination of Wharton's jelly derived mesenchymal stem cells (WJ-MSC) and high frequency repetitive electromagnetic stimulation (rEMS) in the therapy of toxic optic neuropathies with severe symptoms after the available current therapy modalities which were unsucessful.Material and methodsThis prospective, open-label clinical phase-3 study was conducted at Ankara University Faculty of Medicine, Department of Ophthalmology between April 2019 and April 2021. Thirty-six eyes of 18 patients with toxic optic neuropathy (TON) were included in the study. Within 1–3 months after the emergency interventions, patients with various degrees of sequela visual disturbances were studied in this clinical trial. The cases were divided into three groups according to similar demographic characteristics. Group 1: Consists of 12 eyes of 12 patients treated with the WJ-MSC and rEMS combination in one eye. Group 2: Consists of 12 eyes of 12 patients treated with only rEMS in one eye. Group 3: Consists of 12 eyes of six patients treated with only WJ-MSC in both eyes. The course was evaluated by comparing the quantitive functional and structural assessment parameters measured before and at the fourth month of applications in each group.ResultsThe mean best corrected visual acuity (BCVA) delta change percentages of the groups can be ranked as: Group 1 (47%) > Group 3 (32%) > Group 2 (21%). The mean fundus perimetry deviation index (FPDI) delta change percentages of the groups can be ranked as: Group 1 (95%) > Group 2 (33%) > Group 3 (27%). The mean ganglion cell complex (GCC) thickness delta change (decrease in thickness) percentages can be ranked as: Group 1 (− 21%) > Group 3 (− 15%) > Group 2 (− 13%). The visual evoked potential (VEP) P100 latency delta change percentages of the groups can be ranked as: Group 1 (− 18%) > Group 3 (− 10%) > Group 2 (− 8%). The P100 amplitude delta change percentages of the groups can be ranked as: Group 1 (105%) > Group 3 (83%) > Group 2 (24%).ConclusionToxic optic neuropathies are emergent pathologies that can result in acute and permanent blindness. After poisoning with toxic substances, progressive apoptosis continues in optic nerve axons and ganglion cells. After the proper first systemic intervention in intensive care clinic, the WJ-MSC and rEMS combination seems very effective in the short-term period in cases with TON. To prevent permanent blindness, a combination of WJ-MSC and rEMS application as soon as possible may increase the chance of success in currently untreatable cases.Trial Registration ClinicalTrials.gov ID: NCT04877067.

Phase and amplitude electroencephalography correlations change with disease progression in people with idiopathic rapid eye-movement sleep behavior disorder.

Study ObjectivesIncreased phase synchronization in electroencephalography (EEG) bands might reflect the activation of compensatory mechanisms of cognitive decline in people with neurodegenerative diseases. Here, we investigated whether altered large-scale couplings of brain oscillations could be linked to the balancing of cognitive decline in a longitudinal cohort of people with idiopathic rapid eye-movement sleep behavior disorder (iRBD).MethodsWe analyzed 18 patients (17 males, 69.7 ± 7.5 years) with iRBD undergoing high-density EEG (HD-EEG), presynaptic dopaminergic imaging, and clinical and neuropsychological (NPS) assessments at two time points (time interval 24.2 ± 5.9 months). We thus quantified the HD-EEG power distribution, orthogonalized amplitude correlation, and weighted phase-lag index at both time points and correlated them with clinical, NPS, and imaging data.ResultsFour patients phenoconverted at follow-up (three cases of parkinsonism and one of dementia). At the group level, NPS scores decreased over time, without reaching statistical significance. However, alpha phase synchronization increased and delta amplitude correlations decreased significantly at follow-up compared to baseline. Both large-scale network connectivity metrics were significantly correlated with NPS scores but not with sleep quality indices or presynaptic dopaminergic imaging data.ConclusionsThese results suggest that increased alpha phase synchronization and reduced delta amplitude correlation may be considered electrophysiological signs of an active compensatory mechanism of cognitive impairment in people with iRBD. Large-scale functional modifications may be helpful biomarkers in the characterization of prodromal stages of alpha-synucleinopathies.

Consciousness among delta waves: a paradox?

A common observation in EEG research is that consciousness vanishes with the appearance of delta (1-4 Hz) waves, particularly when those waves are high amplitude. High amplitude delta oscillations are frequently observed in states of diminished consciousness, including slow wave sleep, anaesthesia, generalized epileptic seizures, and disorders of consciousness, such as coma and the vegetative state. This strong correlation between loss of consciousness and high amplitude delta oscillations is thought to stem from the widespread cortical deactivation that occurs during the 'down states' or troughs of these slow oscillations. Recently, however, many studies have reported the presence of prominent delta activity during conscious states, which casts doubt on the hypothesis that high amplitude delta oscillations are an indicator of unconsciousness. These studies include work in Angelman syndrome, epilepsy, behavioural responsiveness during propofol anaesthesia, postoperative delirium, and states of dissociation from the environment such as dreaming and powerful psychedelic states. The foregoing studies complement an older, yet largely unacknowledged, body of literature that has documented awake, conscious patients with high amplitude delta oscillations in clinical reports from Rett syndrome, Lennox-Gastaut syndrome, schizophrenia, mitochondrial diseases, hepatic encephalopathy, and non-convulsive status epilepticus. At the same time, a largely parallel body of recent work has reported convincing evidence that the complexity or entropy of EEG and magnetoencephalographic signals strongly relates to an individual's level of consciousness. Having reviewed this literature, we discuss plausible mechanisms that would resolve the seeming contradiction between high amplitude delta oscillations and consciousness. We also consider implications concerning theories of consciousness, such as integrated information theory and the entropic brain hypothesis. Finally, we conclude that false inferences of unconscious states can be best avoided by examining measures of electrophysiological complexity in addition to spectral power.

Oceanic Tide Model FES2014b: Comparison with Gravity Measurements

The oceanic gravimetric effect is calculated by expanding the cotidal maps of the FES2014 oceanic tide model into spherical functions with the use of load Love numbers from the work (Spiridonov and Vinogradova, 2017). The calculation results for the amplitudes and phases of the oceanic gravimetric effect for eight main tidal waves (Q1, O1, P1, K1, N2, M2, S2, and K2) at nine European gravity observation stations of the Global Geodynamic Project (GGP) network are presented. The amplitude delta factors and phase shifts of these tidal waves for the Earth with the ocean are predicted and compared with observations. The difference vectors (prediction minus observations) are analyzed in detail with the use of both different theoretical tide models and oceanic-effect calculation versions. The FES2014 model is included in the ATLANTIDA3.1 tidal prediction software. The results of the work show, first, that the FES2014 is one of the best oceanic models today. The amplitude delta factors and phase shifts of tidal waves calculated with its help for the Earth with the ocean are generally in better agreement with observations when analyzed separately than the FES2012 model results. This is especially evident at Strasbourg and Vienna sites. The analysis of difference vectors implies that FES2014 is slightly inferior to FES2012 in terms of proximity to observations. This fact still requires an explanation. However, the amplitudes of the difference vectors calculated with the FES2012 and FES2014 models usually differ by no more than a few hundredths of a percent of the tidal wave amplitudes. Such small differences can be due to a number of factors unrelated to the oceanic effect.

Ongoing Electroencephalographic Rhythms Related to Exploratory Movements in Transgenic TASTPM Mice.

The European PharmaCog study (http://www.pharmacog.org) has reported a reduction in delta (1-6 Hz) electroencephalographic (EEG) power (density) during cage exploration (active condition) compared with quiet wakefulness (passive condition) in PDAPP mice (hAPP Indiana V717F mutation) modeling Alzheimer's disease (AD) amyloidosis and cognitive deficits. Here, we tested the reproducibility of that evidence in TASTPM mice (double mutation in APP KM670/671NL and PSEN1 M146V), which develop brain amyloidosis and cognitive deficits over aging. The reliability of that evidence was examined in four research centers of the PharmaCog study. Ongoing EEG rhythms were recorded from a frontoparietal bipolar channel in 29 TASTPM and 58 matched "wild type" C57 mice (range of age: 12-24 months). Normalized EEG power was calculated. Frequency and amplitude of individual delta and theta frequency (IDF and ITF) peaks were considered during the passive and active conditions. Compared with the "wild type" group, the TASTPM group showed a significantly lower reduction in IDF power during the active over the passive condition (p < 0.05). This effect was observed in 3 out of 4 EEG recording units. TASTPM mice were characterized by "poor reactivity" of delta EEG rhythms during the cage exploration in line with previous evidence in PDAPP mice. The reliability of that result across the centers was moderate, thus unveiling pros and cons of multicenter preclinical EEG trials in TASTPM mice useful for planning future studies.

Amplitude Delta Factors and Phase Shifts of Tidal Waves for the Earth with the Ocean on the Territory of Russia

The results of the calculation of the amplitude delta factors and phase shifts of semidiurnal and diurnal tidal waves for a rotating self-gravitating ellipsoidal inelastic Earth with the ocean are presented, and the method used to calculate them is briefly described. The maps of distribution of the considered tidal parameters are constructed for the M2 and K1 waves over the territory of Russia; the zones with extreme and generally accepted values are identified. A discussion of the revealed features of the distribution of the amplitude factors and phase shifts on the territory of the Russian Federation is presented.

Association of the retrospective self-report ratings with the dynamics of EEG

The neural underpinnings of subjective experience during resting state remain elusive. Dynamic features of EEG oscillations may provide more understanding of the relationship between the content of inner conscious experience and electrical brain activity. We tested a correlation of rating on the Amsterdam Resting-State Questionnaire (ARSQ) with dynamic parameters of EEG recorded in 49 healthy volunteers during the 10-min resting session. The participants filled ARSQ immediately after the rest. We investigated both linear (1 Hz-band power spectral density - PSD) and dynamic features (standard deviation and frequency of Hilbert envelope) of EEG averaged for the whole resting-state segment. Besides, we conducted a procedure of k-mean clustering based on PSD, localization of components retrieved by independent component analysis for 10-sec EEG epochs to assess spectral and temporal variability of EEG. The correlation analysis showed that the increase of PSD and cluster duration of the high-frequency alpha rhythm (12–13 Hz) in central and frontal areas was positively associated with the rating of experienced thoughts related to Planning (r = 0.44). The time of the presence of low amplitude delta oscillations correlated negatively with Planning (r = -0.52). The participants with higher ARSQ scores of Visual Thoughts had a higher standard deviation of the wideband (1–30 Hz) Hilbert envelope. Our data suggest that the dynamic properties of EEG reflect cognitive states assessed by ARSQ.

ON THE NATURE OF THE HADS STAR V2455 CYG

Using uvby − β photoelectric photometry obtained with the 0.84 m telescope of the Observatorio Astrónomico Nacional de San Pedro Mártir, México, we determined some of the physical characteristics, such as effective temperature and surface gravity of the high amplitude Delta Scuti star V2455 Cyg (=HD 204615). Newly determined times of maximum light gathered at the Observatorio Astrónomico Nacional de Tonantzintla, México with small 10 inch telescopes equipped with CCD cameras were combined with times of maxima in the literature, and used to study the secular variation of the pulsational period of the star.