Relative Amplitude Research Articles

Post-migration seismic data conditioning workflow on a merged dataset

Analyzing amplitude anomalies in seismic data requires a comprehensive understanding of the geological context and the accuracy of the seismic image. Over the past four decades, numerous surveys in mature basins like the US Gulf of Mexico have undergone reprocessing and merging to enhance imaging quality. The merging of seismic data volumes demands careful attention during processing, as the different volumes are often acquired at different times with different hardware, acquisition geometries, and exploration objectives. If insufficient care is taken, significant differences in the amplitude and spectra of the merged survey components can pose challenges when used as input for machine learning techniques or seismic attribute interpretation and studies. We implemented spectral balancing followed by structure-oriented filtering to address the abovementioned discrepancies in a merged survey. Spectral balancing equalizes high and low frequencies, creating a more uniform frequency spectrum. Structure-oriented filtering eliminates random and cross-cutting coherent noise while preserving structural and stratigraphic features. This workflow ameliorates the discrepancies between the areas covered by the individual surveys, resulting in a more consistent interpretation across the seam between the two surveys. This study found that these two processes improved vertical resolution and lateral delineation of fault and stratigraphic edges. However, we also observed in our data that increasing the spectrum runs the risk of increasing the effect of both low and high-frequency noise, including acquisition footprint. Surprisingly, we found that spectral balancing can diminish the appearance of stratigraphic edges that were fortuitously imaged by the original narrowband data volume. Finally, because both spectral balancing and structure-oriented filtering are set to not damage relative amplitudes, we need to apply amplitude gain control to balance them on the shallower parts of the merged survey.

Research on attenuation rate correlation calibration method based on acoustic variable density logging

In order to solve the problem of logging calibration without a free pipe in the process of acoustic variable density logging and the subjective problem of the free pipe calibration method, this paper studies an attenuation rate calibration method based on acoustic variable density logging. Using the developed acoustic wave probe response relationship device and the acoustic wave probe calibration device, the response consistency of the receiving probe of the acoustic wave instrument and the frequency of the transmitting probe can be calibrated in the laboratory, and the response consistency and frequency calibration coefficient can be obtained. Through this coefficient, the acoustic wave attenuation rate can be derived. After converting the acoustic wave attenuation rate into a relative sound amplitude, the scale coefficients of the well can be obtained. The relative acoustic amplitude of each measuring point in the well can be obtained by using the scale coefficient to evaluate the cementing quality. The acoustic variable density field test of 18 wells in the oilfield shows that the relative acoustic amplitude calculation results obtained by the attenuation rate correlation calibration method are basically consistent with the theoretical values, and the maximum deviation is 6.9%. The deviation is caused by the presence of ahead fluid in the outer annulus of the casing, the presence of trace bubbles in the casing, and the incomplete centering of the instrument. Compared with the traditional free pipe calibration method, the attenuation rate correlation calibration method innovatively replaces the free pipe calibration in the well with the indoor calibration of the acoustic instrument and solves the problem of acoustic variable density calibration when there is no free pipe in cementing quality logging. This method has better accuracy and a greater application range, which lays a foundation for the quantitative interpretation of acoustic variable density.

Numerical Simulation Analysis of Laser Ultrasonic Detection of Defects in Silicon Carbide

Silicon carbide (SiC) is widely used in power electronic devices and other fields, the defects of which can significantly impact its performance in device fabrication. Laser ultrasonic non-destructive testing (NDT) as a novel and effective approach can detect these defects in real time. This study introduces a numerical model for the SiC NDT that elucidates the dynamic interactions between laser-induced ultrasonic waves and surface defects, and internal defects in SiC, respectively. Results show NDT is an effective way to locate the SiC defect and the ultrasonic waves’ vibration amplitude of detection points at defect edges increases by at least 16% compared to adjacent points, with a maximum of 43%. A comparative assessment between surface and internal defect vibration responses for acoustic is also made. For internal defects, the oscillation time of the acoustic wave at the detection point on the surface away from the edge of the defect at the excitation point exceeds that of surface defects by 100 ns, and the amplitude near the excitation point is more pronounced, reaching 1.44 nm, which is 4.2 times that of corresponding surface defects. Additionally, a linear relationship is observed between the arrival time of transmitted Rayleigh Waves (RSR) and internal defect length, with a correlation coefficient of 0.9878. Similarly, a linear relationship is established between the amplitude of reflected Rayleigh Waves (rR) and defect width, with a correlation coefficient of 0.9976, providing an effective way to quantify the inner defect. Furthermore, transient temperature profiles at distinct positions and transient acoustic fields and the relationship of acoustic vibration amplitude increasing with laser spot size under a fixed laser power density are also analyzed. This model provides a theoretical foundation for laser ultrasonic NDT setup and choice of micro-vibration detection device.

Maximizing the translational potential of neurophysiology in amyotrophic lateral sclerosis: a study on compound muscle action potentials

Mouse models of amyotrophic lateral sclerosis (ALS) enable testing of novel therapeutic interventions. However, treatments that have extended survival in mice have often failed to translate into human benefit in clinical trials. Compound muscle action potentials (CMAPs) are a simple neurophysiological test that measures the summation of muscle fiber depolarization in response to maximal stimulation of the innervating nerve. CMAPs can be measured in both mice and humans and decline with motor axon loss in ALS, making them a potential translational read-out of disease progression. We assessed the translational potential of CMAPs and ascertained time points when human and mouse data aligned most closely. We extracted data from 18 human studies and compared with results generated from SOD1G93A and control mice at different ages across different muscles. The relative CMAP amplitude difference between SOD1G93A and control mice in tibialis anterior (TA) and gastrocnemius muscles at 70 days of age was most similar to the relative difference between baseline ALS patient CMAP measurements and healthy controls in the abductor pollicis brevis (APB) muscle. We also found that the relative decline in SOD1G93A TA CMAP amplitude between 70 and 140 days was similar to that observed in 12 month human longitudinal studies in APB. Our findings suggest CMAP amplitudes can provide a “translational window”, from which to make comparisons between the SOD1G93A model and human ALS patients. CMAPs are easy to perform and can help determine the most clinically relevant starting/end points for preclinical studies and provide a basis for predicting potential clinical effect sizes.

First fluctuation measurements using an Imaging Neutral Particle Analyzer on DIII-D

Abstract A recent upgrade to the Imaging Neutral Particle Analyzer (INPA) on DIII-D has allowed for the first fluctuation measurements using an INPA to be taken during a neoclassical tearing mode (NTM). The INPA signal tracked the mode over 150 ms as the mode frequency dropped to zero, capturing both the NTM with poloidal and toroidal mode numbers $m/n=2/1$ and a $3/2$ mode at double the frequency. Analysis shows that the signals originate from charge exchange events near the edge of the plasma, and relative fluctuation amplitudes are greater than 25% for the duration of the NTM. Filtered signals show frequency beating patterns that are phase-space dependent. Simulated signal is dominated by prompt transport from the neutral beams to the INPA sightline, while the contribution from the slowing down distribution is significantly lower. Simulated measurements in the range of pitches that the diagnostic is sensitive to (0.5≤|v∥/v|≤ 0.75) show the signal is dominated by trapped orbits that pass through magnetic islands near the edge of the plasma. Calculations of expected fluctuation levels show that only direct interaction with the NTM can provide the strong relative fluctuation levels seen experimentally. The prompt nature of the orbits and thin radial layer found to contribute to synthetic signals suggest INPA passive data may be used to measure the perturbations of confined orbits on a single pass through a plasma instability.

Circadian rest-activity rhythm pattern in the elderly with cerebral small vessel disease: Using multiple estimated methods.

Background: Disruption of circadian rest-activity rhythm (RAR) has been found in many neurological disorders. Objective: In this study, actigraphic data were collected and analyzed to identify the RAR pattern in the elderly with cerebral small vessel disease. Methods: 115 cerebral small vessel disease (CSVD) cases were recruited. The presence of lacune infarct, white matter hyperintensities, and cerebral microbleeds in magnetic resonance imaging (MRI) images were rated independently, as well as using a simple MRI score of 0-3 points. Each subject wore an Actigraph device in their nondominant hand for 4-7 days to collect raw data. RAR parameters were generated using both extended cosinor model (RAR α, RAR β, amplitude, acrophase, up-mesor, down-mesor, and pseudo-F statistic) and non-parametric methods (interdaily stability, intradaily variability, and relative amplitude). Results: Elder patients with a simple MRI score of 2-3 points showed a statistically lower amplitude compared with individuals with a simple MRI score of 0 points in the extended cosinor model. For the non-parametric method, elderly people with a simple MRI score of 1-3 points exhibited higher intradaily variability relative to those participants with a simple MRI score of 0 points. However, no differences were found regarding sleep quality among individuals with different simple MRI scores. White matter hyperintensities, lacune infarct, and cerebral microbleeds were independently associated with RAR β, RAR α, and intradaily variability, respectively. Conclusions: The RAR pattern was disturbed in elderly adults with CSVD. Abnormal RAR parameters were independently associated with CSVD MRI markers.

Assessing the effects of drought stress on photosynthetic performance and physiological resistance in camphor seedling leaves.

The impact of seasonal short-term drought on plant physiology and resilience is crucial for conservation and management strategies. This study investigated drought stress effects on growth, photosynthetic capacity, and physiological responses of Camphor (Cinnamomum camphora) seedlings in Guangxi province, China. Fertilized potted plants underwent continuous drought treatments to assess varying water supply effects. Treatments included normal water supply (CK), light drought (D1), moderate drought (D2), and severe drought (D3). Physiological indicators including net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), and intercellular CO2 concentration (Ci) were measured. Additionally, the stomatal limitation value (Ls) was calculated using the formula Ls = 1-Ci/Ca, and water use efficiency (WUE) was computed as Pn/Tr. Furthermore, parameters such as PIABS (Performance Index based on absorbed light energy), WK (the ratio of variable fluorescence FK at the K point to the amplitude FO-FJ), VJ (the ratio of variable fluorescence FJ at the J point to the amplitude FO-FP), ΔI/I0 (the relative amplitude of the 820 nm light absorption curve), superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and malondialdehyde (MDA) were measured to evaluate the impact of drought stress on various physiological processes and antioxidant enzyme activities. Results showed significant decreases in base diameter growth (GD) and seedling height growth (GH) with increasing drought stress. Notably, moderate (D2) and severe (D3) drought treatments led to negative GD values. GD decreased by 23.79%, 114.85%, and 175.50% for D1, D2, and D3 treatments, respectively, while reductions of 40.00%, 73.33%, and 90.00% in GD were observed compared to the control (CK). Pn decreased significantly across treatments, with D1<CK<D2<D3 in Ci. Stomatal limit value (Ls) and water use efficiency (WUE) followed the order: D1>CK>D2>D3. Light energy transmission to PSI by the unit reaction center (REo/RC) initially increased then decreased, significantly smaller in D3 compared to D1. Conversely, heat dissipation absorbed by the unit reaction center (DIo/RC) increased notably in D3 compared to D1 and CK. PIABS, WK, VJ, and ΔI/I0 decreased over time, while Rubisco enzyme activity decreased, while proline (Pro) levels increased. Superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and malondialdehyde (MDA) levels significantly increased during D1 treatment but decreased with D2 and D3 treatments. Overall, drought severity had varying impacts on Cinnamomum camphora growth and photosynthetic structure, with D1 treatment maintaining normal growth and metabolic activities, while D2 and D3 treatments resulted in severe membrane damage, rendering seedlings essentially unable to survive. These findings provide a theoretical basis for implementing water management practices and conservation strategies for camphor seedlings.

Graphene/F16CuPc synaptic transistor for the emulation of multiplexed neurotransmission

We demonstrate a bipolar graphene/F16CuPc synaptic transistor (GFST) with matched p-type and n-type bipolar properties, which emulates multiplexed neurotransmission of the release of two excitatory neurotransmitters in graphene and F16CuPc channels, separately. This process facilitates fast-switching plasticity by altering charge carriers in the separated channels. The complementary neural network for image recognition of Fashion-MNIST dataset was constructed using the matched relative amplitude and plasticity properties of the GFST dominated by holes or electrons to improve the weight regulation and recognition accuracy, achieving a pattern recognition accuracy of 83.23%. These results provide new insights to the construction of future neuromorphic systems.

Characterization of seven transiting systems, including four warm Jupiters from SOPHIE and TESS

While several thousand exoplanets are now confirmed, the number of known transiting warm Jupiters ($10 d period d $) remains relatively small. These planets are generally believed to have formed outside the snowline and migrated to their current orbits. Because they are sufficiently distant from their host stars, they mitigate proximity effects and so offer valuable insights into planet formation and evolution. Here, we present the study of seven systems, three of which -- TOI-2295, TOI-2537, and TOI-5110 -- are newly discovered planetary systems. Through the analysis of TESS photometry, SOPHIE radial velocities (RVs), and high-spatial resolution imaging, we found that TOI-2295b, TOI-2537b, and TOI-5110b are transiting warm Jupiters with orbital periods ranging from 30 to 94 d, masses between 0.9 and 2.9 M_ J and radii ranging from 1.0 to 1.5 R_ J . Both TOI-2295 and TOI-2537 harbor at least one additional, outer planet. Their outer planets -- TOI-2295c and TOI-2537c -- are characterized by orbital periods of 966.5^ and 1920^ d, respectively, and minimum masses of 5.61^ and 7.23^ M_ J respectively. We have also investigated and characterized the two recently reported warm Jupiters TOI-1836b and TOI-5076b, which we independently detected in SOPHIE RVs. Our new data allow for further discussion of their nature and refinement of their parameters. Additionally, we study the planetary candidates TOI-4081.01 and TOI-4168.01. For TOI-4081.01, despite our detection in RVs, we cannot rule out perturbation by a blended eclipsing binary, and we thus exercise caution regarding its planetary nature. On the other hand, we identify TOI-4168.01 as a firm false positive; its RV curve exhibits a large amplitude in an antiphase relation with the transit ephemeris observed by TESS, indicating that the detected event is the eclipse of a secondary star rather than a planetary transit. Finally, we highlight interesting characteristics of these new planetary systems. The transits of TOI-2295b are highly grazing, with an impact parameter of 1.056^ . This leaves its radius uncertain but potentially makes it an interesting probe of gravitational dynamics in its two-planet system, as transit shapes for grazing planets are highly sensitive to even small variations in inclination. TOI-2537b, in turn, is a temperate Jupiter with an effective temperature of 307±15 K and can serve as a valuable low-irradiation control for models of hot Jupiter inflation anomalies. We also detected significant transit timing variations (TTVs) for TOI-2537b, which are likely caused by gravitational interactions with the outer planet TOI-2537c. Further transit observations are needed to refine the analysis of these TTVs and enhance our understanding of the system’s dynamics. Finally, TOI-5110b stands out due to its orbital eccentricity of 0.745^ one of the highest planetary eccentricities discovered thus far. We find no conclusive evidence for an external companion, but an unseen planet with a semi-amplitude smaller than 10 m/s could nonetheless still be exciting its eccentricity.

Relaxation process of photoexcited berberine via aggregation and dissociation state-dependent intramolecular electron transfer.

Thefluorescence quantum yield of berberine in aqueous solution is significantly smaller than those of organic solution. The time profile of fluorescence intensity of berberine was analyzed by a bi-exponential function, showing that two kinds of states of berberine exist in the solutions. The observed fluorescence lifetime of shorter lifetime species of berberine in water (0.08ns) was markedly smaller than those of organic solvents and the relative amplitude of the shorter lifetime was dominated in the aqueous solution. Thus, this shorter lifetime can be explained by the deactivation via intramolecular electron transfer. These two states of berberine were independent of pH. The enthalpy and entropy changes between these two states were - 23.2kJmol-1 and - 90JK-1mol-1, supporting the aggregation of berberine. In the aggregation state, an electrostatic interaction between cationic berberine and chloride ion decreases the electron accepting ability of the isoquinoline moiety of berberine, resulting in the suppression of intramolecular electron transfer. Furthermore, in the presence of clay, the interaction between berberine and clay increased the fluorescence intensity of berberine and its lifetime, showing that the negative charge of clay suppresses the intramolecular electron transfer. Since the electron transfer quenching of the photo-excited berberine is advantageous for suppressing the phototoxic effect of berberine, the inhibition of berberine aggregation is an important process for the phototoxicity prevention.

Variations in the radiation intensity of the pulsar B0950+08: 9 years of monitoring at a frequency of 110 MHz

The analysis of variations in the radiation intensity of the pulsar B0950+08 from 2014 to 2022 with scales from minutes to years was carried out. The observations were obtained in a round-the-clock daily survey conducted on the Large Phased Array (LPA) radio telescope. The high variability of radiation is shown not only from pulse to pulse, but also at scales greater than 3 min. The average value of the estimated amplitude of these variations in 3.2 minutes is 25 Jy, the modulation index is 1. The average relative amplitude of the interpulse (IP) is 2.00 ± 0.28 % of the main pulse. In individual pulses, the amplitude of the interpulse may exceed the amplitude of the main pulse (MP), but this is a rare event. Radiation is observed in almost the entire period of the pulsar. For the first time, the relative amplitude of radiation between the main pulse and the interpulse (radiation bridge) was measured. When averaging about 10 hours, it varies from 0.8% to 1.31% with an average value of 1.04 ± 0.28 %. A high correlation was found between MP and IP amplitude variations both when averaging profiles over 3.2 minutes and when averaging over years. This correlation is due to refractive interstellar scintillation. The frequency scale of IP diffraction interstellar scintillation was measured for the first time and it was shown that the spectral forms for IP and MP are well correlated and have the same frequency scale. There are strong variations in the frequency scale of scintillation f dif from session to session (time interval from one day) on scales of 200–800 kHz. The refractive scale of scintillation for 1–2 days has been determined. A modulation of radiation with a characteristic scale of about 130 days was detected, which, apparently, is also associated with refractive scintillation.

Cross-sectional relationships of circadian misalignment and rest-activity rhythms with occupational attainment in UK Biobank participants.

Circadian misalignment and disrupted rest-activity rhythms have been linked to adverse health and educational outcomes, yet few studies have considered their relationships with economic outcomes. We investigate associations between multiple accelerometer-measured circadian misalignment traits (Composite Phase Deviation and the Sleep Regularity Index) and rest-activity rhythm traits (Inter-daily Stability, Intra-daily variability and relative amplitude), with occupational attainment, measured using the average wage paid to an individual's occupation. We use data from 20 356 UK Biobank participants who wore an accelerometer (2013-16), provided employment data for the year they wore the accelerometer, and supplied covariate data at recruitment (2006-10). We use linear regression, with incremental adjustments for four sets of covariates, and stratify our analysis by sex. Our findings provide mixed evidence on the relationship between circadian misalignment and occupational attainment, varying by the measure of circadian misalignment used, and sex. We find fragmented rest-activity rhythms to be associated with higher occupational attainment, which is counterintuitive. Since circadian misalignment is a modifiable trait, our results suggest potential benefits of policies aimed at reducing circadian misalignment, such as altering work schedules and reducing bright light exposure in the evening. Further research is needed to elucidate the mechanisms through which rest-activity rhythms may impact economic outcomes.

Differential‐sampling control algorithm and theoretical analysis for programmable‐Josephson‐voltage‐standard traceability application

AbstractThe programmable Josephson voltage standard (PJVS) provides a new way and higher accuracy for the traceability of traditional measurement standards. To improve the applicability and reduce the uncertainty of the PJVS, a PJVS‐based analog‐to‐digital converter (ADC) scheme for the alternating‐current (AC) voltage measurement is proposed and the theoretical error model is derived based on discrete Fourier transform. The influence of the amplitude and phase error of the AC voltage is simulated; an adaptive differential‐sampling control algorithm is proposed to control the relative amplitude and phase between the AC voltage and PJVS voltage, improving the error of the PJVS‐based ADC. Furthermore, the authors obtained the exponential decay algorithm error curve that varies with phase error and the M‐shaped variation curve with sampling error by simulation and a PJVS‐based ADC with different sampling DVM, which provides possibilities for optimizing the measurement error of the PJVS‐based ADC.

Blood Pressure Estimation Using Explainable Deep-Learning Models Based on Photoplethysmography.

Due to their invasiveness, arterial lines are not typically used in routine monitoring, despite their superior responsiveness in hemodynamic monitoring and detecting intraoperative hypotension. To address this issue, noninvasive, continuous arterial pressure monitoring is necessary. We developed a deep-learning model that reconstructs continuous mean arterial pressure (MAP) using the photoplethysmograhy (PPG) signal and compared it to the arterial line gold standard. We analyzed high-frequency PPG signals from 117 patients in neuroradiology and digestive surgery with a median of 2201 (interquartile range [IQR], 788-4775) measurements per patient. We compared models with different combinations of convolutional and recurrent layers using as inputs for our neural network high-frequency PPG and derived features including dicrotic notch relative amplitude, perfusion index, and heart rate. Mean absolute error (MAE) was used as performance metrics. Explainability of the deep-learning model was reconstructed with Grad-CAM, a visualization technique using saliency maps to highlight the parts of an input that are significant for a deep-learning model decision-making process. An MAP baseline model, which consisted only of standard cuff measures, reached an MAE of 6.1 (± 14.5) mm Hg. In contrast, the deep-learning model achieved an MAE of 3.5 (± 4.4) mm Hg on the external test set (a 42.6% improvement). This model also achieved the narrowest confidence intervals and met international standards used within the community (grade A). The saliency map revealed that the deep-learning model primarily extracts information near the dicrotic notch region. Our deep-learning model noninvasively estimates arterial pressure with high accuracy. This model may show potential as a decision-support tool in operating-room settings, particularly in scenarios where invasive blood pressure monitoring is unavailable.

Giant Ultrabroadband Bulk Photovoltaic Effect Engendered by Two-Photon Absorption in α-In2Se3 for Chiral Terahertz Wave Generation.

Bulk photovoltaic effect (BPVE) can break the Shockley-Queisser limit by leveraging the inherent asymmetry of crystal lattice without a junction. However, this effect is mainly confined to UV-vis spectrum due to the wide-bandgap nature of traditional ferroelectric materials, thereby limiting the exploration of the infrared light-driven efficient BPVE. Herein, giant two-photon absorption (TPA) driven BPVE is uncovered from visible to infrared in ferroelectric α-In2Se3 utilizing wavelength-tunable terahertz (THz) emission spectroscopy. Remarkably, α-In2Se3 exhibits exceptional THz emission efficiency in the infrared region, surpassing renowned THz emitters like p-InAs and achieving an efficiency approximately eight times the magnitude of standard ZnTe. The power exponent-type pump fluence and quadruple polarization features reveal a unique TPA-driven BPVE, corroborated by a fourth-order nonlinear oscillator model. Notably, TPA-engendered BPVE efficiency approaches 68% of that observed in the single-photon absorption process. Moreover, the TPA responses display clear polarization anisotropy, with considerably relative phase and amplitude driven by synchronous in-plane and out-of-plane polarization, leading to chiral THz waves with high efficiency, tunable orientation, and controllable ellipticity. This work highlights the advantages of TPA-induced BPVE responses in narrow-bandgap ferroelectric semiconductors, enhancing spectral utilization efficiency, aiding high-performance devices based on BPVE, and guiding chiral THz wave design.

Hearing in Two Closely Related Peromyscus Species (Peromyscus maniculatus and P. leucopus).

The genus Peromyscus has been extensively used as a model for ecological, behavioral, and evolutionary investigations. We used auditory brainstem responses (ABRs), craniofacial morphology, and pinna measurements to compare characteristics that impact hearing in two wild-caught species, P. leucopus P. maniculatus. We observed significant statistical differences in craniofacial and pinna attributes between species with P. leucopus overall exhibiting larger features than P. maniculatus. ABR recordings indicated that both species showed similar best frequency thresholds between 8-24 kHz. We found significant effects of intensity on amplitude ratio of wave I and IV for P. maniculatus, but not P. leucopus and effects of wave number on slope of the latency-intensity function with higher wave IV and shorter wave I slope of latency intensity function in P. leucopus. Finally, the data showed significant differences in latency shift of the DN1 component of the BIC in relation to ITD between species, while no significant differences were observed across relative DN1 amplitude. This study supports the used of P. leucopus and P. maniculatus as future model species for auditory research.

Circadian rhythm and epilepsy: a nationally representative cross-sectional study based on actigraphy data.

The study aims to assess the relationship between epilepsy and circadian rhythms. This study included a cohort of 7,410 participants sourced from the 2013-2014 National Health and Nutrition Examination Survey (NHANES) database. The investigation focused on the comparative analysis of seven nonparametric indices associated with circadian rhythms (Interdaily Stability (IS), Intradaily Variability (IV), Relative Amplitude (RA), L5, M10, L5 start time, and M10 start time) between the overall population and patients with epilepsy. Logistic regression analysis was utilized to assess the potential correlation between the rest-activity circadian rhythm patterns and the presence of epilepsy within the cohort. Compared to the general population, individuals with epilepsy exhibited lower values of IS and M10. Multivariable logistic regression analysis, when IS, RA, and M10 were categorized into four groups based on quartiles, revealed that the odds ratio (IS: OR = 0.36, 95% CI: 0.13, 0.89; RA: OR = 0.25, 95% CI: 0.06, 0.77; M10: OR = 0.24, 95% CI: 0.06, 0.73) for the highest quartile was lower than that for the lowest quartile. Furthermore, after adjustment for confounding factors, participants in the highest quartile compared to those in the lowest quartile of IV and M10 start time demonstrated a higher prevalence of epilepsy. Individuals with epilepsy demonstrate significant alterations in circadian rhythms.

Comparative assessment of resonant frequencies of the floor of suburban electric train cars

The work is devoted to the study of the resonant frequency characteristics of the floor of passenger cars for the modernization of suburban electric trains of the EPL2, EPL9 series. A horizontal vibrator loading scheme was adopted for the experiments. The aim of the study is an experimental comparative assessment of the resonant frequencies of the floor of cars with different variants of the structural structure. An experimental and computational method for determining the resonant frequency of the oscillatory system based on limited experimental data, namely the excitation frequency and the measured coefficient of reduction of the force amplitude, is proposed. Based on the tests, the frequency characteristics of the relative change in the amplitude of accelerations on the surface of the floor of different structures were obtained. The relative amplitudes are presented in the form of the amplitude growth coefficient k. It is found that the floor amplitude growth coefficient does not depend on the excitation amplitude and depends only on the frequency. The frequency characteristics of the floor design options with rubber shock absorbers differ significantly from the basic version in terms of resonant frequency – 104 Hz versus 69–75 Hz. The introduction of layers of the vibration damping membrane into the design scheme has a minor effect on the resonant frequency of the floor: 75–71–69 Hz.

Sleep Fragmentation Despite Intact Rest-Activity Patterns in Premanifest Huntington's disease: An Actigraphy Study

ObjectiveSleep research in Huntington’s disease (HD) has primarily focused on manifest HD, with significantly less attention given to premanifest HD (Pre-HD). Therefore, we investigated sleep and rest-activity patterns in people with Pre-HD versus healthy controls (HC). MethodsWe conducted a cross-sectional study including 36 Pre-HD and 48 HC participants. Pre-HD participants were stratified into three groups according to their proximity to estimated diagnosis, using a cytosine-adenine-guanine (CAG) and current age-based predictive model: NEAR (<9 years to diagnosis), MID (9-15 years to diagnosis) and FAR (>15 years to diagnosis). Sleep and rest-activity patterns were assessed using wrist-worn actigraphy, a sleep diary, and sleep questionnaires. ResultsNEAR and MID groups experienced higher fragmentation index than HC and FAR groups. NEAR and MID groups also exhibited greater WASO than the FAR group. NEAR and MID groups showed lower intra-daily variability (IV) than HC and FAR groups, with the NEAR group also being more active in the most active 10 hours (M10). Groups did not differ on subjective sleep measures, inter-daily stability (IS), sleep regularity index, relative amplitude, or amount of activity in the least active five hours (L5). Considering all Pre-HD participants, fewer years to diagnosis, higher CAG-age-product (CAP) scores (a measure of cumulative exposure to the HD-causing gene mutation) and larger CAG repeat lengths correlated with higher WASO, fragmentation index, L5, IS, and lower sleep efficiency and IV. Higher CAP score correlated with higher M10. ConclusionsDespite intact rest-activity patterns and similar subjective sleep quality to HC, greater sleep fragmentation is a prominent and early feature in Pre-HD. Therefore, reducing sleep fragmentation may be a potential target for sleep intervention in HD. Longitudinal studies using larger samples are needed to assess sleep across the disease spectrum and its impact on clinical outcomes, like cognition.

Orbital (Hydro)Climate Variability in the Ice-Free Early Eocene Arctic.

Early Eocene (∼56-48Ma) climates are useful to investigate polar climate dynamics in the absence of ice. We explore early Eocene orbital variability of Arctic climate using sediments recovered by the Arctic Coring Expedition (ACEX). High resolution records of lipid biomarkers (GDGTs; 2-kyr) and palynological assemblages (5-kyr) in the ∼4m interval below Eocene Thermal Maximum 2 (∼54Ma) show cyclic signals related to ∼20-kyr precession, ∼40-kyr obliquity, and ∼100-kyr eccentricity. Biomarkers indicate obliquity and precession variability representative of sea surface temperature (SST) variations up to ∼1.4 and ∼0.5°C, respectively. Peak SSTs coincide with an elevated supply of pollen and spores and increased marine productivity. This implies an orbital control on precipitation and terrestrial nutrient supply to the Arctic Basin. Assuming that SST maxima correspond to Arctic insolation maxima (precession minima/obliquity maxima), precipitation maxima also correspond to insolation maxima, implying regional hydrological processes as a forcing rather than variations in meridional water transport, contrasting Pleistocene Arctic hydrology. The relative amplitudes of precession and obliquity in the SST record match that of local insolation between spring and fall, corroborating a seasonal GDGT bias. The reconstructed complete orbital imprint refutes a bias to one end of the orbital variability. Eccentricity-related SST variability was ∼0.8°C, ∼2-3 times higher than synchronous variability in the deep ocean, and 3-4 times higher than similar variations in the tropics. This confirms eccentricity-forced global temperature variability and that this had pronounced polar amplification, despite the absence of ice-albedo feedbacks.