Total Power Spectrum Research Articles

Analysis of heart rate variability in assessing the autonomic status of tuberculosis patients and in combination with HIV infection

In this study, a comprehensive instrumental assessment of the autonomic status of tuberculosis patients and those with concomitant HIV infection at the beginning and during treatment was conducted, revealing the structure of dysfunction through heart rate variability analysis. Correcting the identified disorders will enhance the effectiveness of treatment through a comprehensive individualized approach.The aim of the study: to assess the autonomic status of patients with tuberculosis and concomitant HIV infection during the course of treatment using spectral analysis of heart rate variability and to determine its clinical significance.Materials and methods. The study involved 195 participants. They were divided into two groups: a control group of 70 healthy individuals and an observation group of 125 newly diagnosed patients with infiltrative and disseminated pulmonary tuberculosis, further divided into two subgroups. The first subgroup included 64 patients with pulmonary tuberculosis, and the second subgroup included 61 patients with tuberculosis combined with HIV infection. The structure of the autonomic nervous system was studied using the computer complex «Varicard 2.51» for processing variocardiograms and analyzing heart rate variability (Registration certificate for medical device dated 10.12.2007 No. FSR 2007/01390). All patients were examined under identical conditions. Calculations were performed using SPSS Statistics v. 23.Results and discussion. The data on the assessment of the state and dynamics of the total power spectrum of RR intervals (TP) in the control group and in patients with tuberculosis and concomitant HIV infection in subgroups 1 and 2 of the observation group during treatment are presented. When comparing the frequency of TP above the «normal zone» in the control group and subgroup 1 of the observation group (t1= 3.30; p1<0.01; t2=1.70; p2>0.05), in the control group and subgroup 2 of the observation group (t1=3.51; p1<0.01; t2=2.64; p2<0.01), statistically significant differences were found in subgroup 1 before treatment and in subgroup 2 before and after treatment. The significant decrease in TP levels above the «normal zone» in patients of subgroups 1 and 2 before treatment indicated significant mobilization of the body’s regulatory system reserves needed to maintain vital functions. By the end of the hospital treatment stage, TP levels had not recovered in patients of subgroup 2, marking more pronounced regulatory disturbances in patients with pulmonary tuberculosis combined with HIV infection.Conclusion. The assessment of the state of regulatory systems and the body’s reserves based on heart rate variability indicators showed that in healthy individuals, these systems were at levels ensuring the body’s normal homeostatic balance with the regulatory systems functioning normally without excessive stress and high resource mobilization. In patients with pulmonary tuberculosis, the state of regulatory systems was at a lower level, especially in patients with concomitant HIV infection.

Inflationary initial conditions for the cosmological gravitational wave background

The initial conditions on the anisotropies of the stochastic gravitational-wave background of cosmological origin (CGWB) largely depend on the mechanism that generates the gravitational waves. Since the CGWB is expected to be non-thermal, the computation of the initial conditions could be more challenging w.r.t. the Cosmic Microwave Background (CMB), whose interactions with other particles in the early Universe lead to a blackbody spectrum. In this paper, we show that the initial conditions for the cosmological background generated by quantum fluctuations of the metric during inflation deviate from adiabaticity. These primordial gravitational waves are indeed generated by quantum fluctuations of two independent degrees of freedom (the two polarization states of the gravitons). Furthermore, the CGWB plays a negligible role in the Einstein's equations, because its energy density is subdominant w.r.t. ordinary matter. Therefore, the only possible way to compute the initial conditions for inflationary gravitons is to perturb the energy-momentum tensor of the gravitational field defined in term of the small-scale tensor perturbation of the metric. This new and self-consistent approach shows that a large, non-adiabatic initial condition is present even during the single-field inflation. Such a contribution enhances the total angular power spectrum of the CGWB compared to the standard adiabatic case, increasing also the sensitivity of the anisotropies to the presence of relativistic and decoupled particles in the early Universe. In this work we have also proved that our findings are quite general and apply to both single-field inflation and other scenarios in which the CGWB is generated by the quantum fluctuations of the metric, like the curvaton.

The association between physiological and eye-tracking metrics and cognitive load in drivers: A meta-analysis

Driving performance can be impaired by a high cognitive load of drivers. Thus, it is important to estimate drivers’ cognitive load. Although physiological and eye-tracking metrics have been widely used in many studies to assess cognitive load while driving, conflicts still exist regarding the association between physiological and eye-tracking metrics and different levels of cognitive load. Through a meta-analysis, our study aims to quantify the association between physiological, eye-tracking metrics and cognitive load induced by n-back tasks. A total of 18 articles met the inclusion criteria for the meta-analysis. The results indicate four types of metrics, including the sensitive-to-low ones that can only differentiate the low to medium level of cognitive load (i.e., the power spectrum of θ wave of electroencephalogram at Fp1 channel); high-resolution ones that can differentiate all levels of cognitive load (including pupil size, heart rate, and skin conductance); and low-resolution ones that can only differentiate low and high cognitive load (including the total power spectrum of electrocardiogram, eye blink rate, and respiration rate) and others (the power spectrum of θ wave of electroencephalogram at Fp2 channel). Furthermore, the association between metrics and cognitive load can be modulated by the n-back version, modality of n-back task, automation level, and percentage of male participants. In summary, this study contributes to the literature by quantifying associations between physiological and eye-tracking metrics and different cognitive load levels. Practically, we provide evidence for the selection of physiological and eye-tracking metrics for future driving cognitive load monitoring system design.

Общая мощность спектра и мощность HF-волн в зависимости от этапов годичного цикла подготовки спортсменов и других факторов (обзор)

As part of the study into the nature of such heart rate variability (HRV) indicators as total spectrum power (TP), absolute power of high frequency waves (HFAP) and their relative power (as a percentage of TP (HF%)), literature data and the results of our own research on the values of these indicators in athletes are systematized. It has been established that TP, HFAP and HF% depend on the type of sports (reaching their maximum in endurance training), experience in sports (the higher the level, the higher these indicators), and phase of the training year (increasing during the preparatory phase, but decreasing slightly in the competitive phase and more significantly during the transition phase). In particular, the paper presents the results of the study of the first author of this article, elite skier D.A. Kataev, who recorded his own cardiointervalogram and the volume and intensity of daily training loads during one training year. This made it possible to evaluate TP, HFAP and HF% dynamics over the three phases and to establish that TP values are directly dependent on the volume and intensity of training loads. However, no such relationship was established for HFAP and HF%. It was shown that in 8 cross-country skiers (members of the Tatarstan national team) TP, HFAP and HF% values during the preparatory phase were higher than in the competition phase. The authors conclude that TP, HFAP and HF% values mainly reflect the influence of the parasympathetic division of the autonomic nervous system (ANS) on athletes’ cardiac activity, as well as on the activation of the sympathetic division of the ANS during the development of precompetition emotional stress in the competitive phase. An idea is postulated about the formation of the anti-apoptotic myocardial system during endurance training, which includes antioxidants, dopamine, serotonin, acetylcholine, prostaglandins, nitric oxide and other compounds.

Cosmological baryon spread and impact on matter clustering in CAMELS

ABSTRACT We quantify the cosmological spread of baryons relative to their initial neighbouring dark matter distribution using thousands of state-of-the-art simulations from the Cosmology and Astrophysics with MachinE Learning Simulations (CAMELS) project. We show that dark matter particles spread relative to their initial neighbouring distribution owing to chaotic gravitational dynamics on spatial scales comparable to their host dark matter halo. In contrast, gas in hydrodynamic simulations spreads much further from the initial neighbouring dark matter owing to feedback from supernovae (SNe) and active galactic nuclei (AGN). We show that large-scale baryon spread is very sensitive to model implementation details, with the fiducial simba model spreading ∼40 per cent of baryons >1 Mpc away compared to ∼10 per cent for the IllustrisTNG and astrid models. Increasing the efficiency of AGN-driven outflows greatly increases baryon spread while increasing the strength of SNe-driven winds can decrease spreading due to non-linear coupling of stellar and AGN feedback. We compare total matter power spectra between hydrodynamic and paired N-body simulations and demonstrate that the baryonic spread metric broadly captures the global impact of feedback on matter clustering over variations of cosmological and astrophysical parameters, initial conditions, and (to a lesser extent) galaxy formation models. Using symbolic regression, we find a function that reproduces the suppression of power by feedback as a function of wave number (k) and baryonic spread up to $k \sim 10\, h$ Mpc−1 in SIMBA while highlighting the challenge of developing models robust to variations in galaxy formation physics implementation.

The Potential of Exercise on Lifestyle and Skin Function: Narrative Review.

The skin is an important organ of the human body and has moisturizing and barrier functions. Factors such as sunlight and lifestyle significantly affect these skin functions, with sunlight being extremely damaging. The effects of lifestyle habits such as smoking, diet, and sleep have been studied extensively. It has been found that smoking increases the risk of wrinkles, while excessive fat and sugar intake leads to skin aging. Lack of sleep and stress are also dangerous for the skin's barrier function. In recent years, the impact of exercise habits on skin function has been a focus of study. Regular exercise is associated with increased blood flow to the skin, elevated skin temperature, and improved skin moisture. Furthermore, it has been shown to improve skin structure and rejuvenate its appearance, possibly through promoting mitochondrial biosynthesis and affecting hormone secretion. Further research is needed to understand the effects of different amounts and content of exercise on the skin. This study aims to briefly summarize the relationship between lifestyle and skin function and the mechanisms that have been elucidated so far and introduce the expected effects of exercise on skin function. We conducted a review of the literature using PubMed and Google Scholar repositories for relevant literature published between 2000 and 2022 with the following keywords: exercise, skin, and life habits. Exercise augments the total spectrum power density of cutaneous blood perfusion by a factor of approximately 8, and vasodilation demonstrates an enhancement of approximately 1.5-fold. Regular exercise can also mitigate age-related skin changes by promoting mitochondrial biosynthesis. However, not all exercise impacts are positive; for instance, swimming in chlorinated pools may harm the skin barrier function. Hence, the exercise environment should be considered for its potential effects on the skin. This review demonstrates that exercise can potentially enhance skin function retention.

Cluster analysis as a tool for quantifying structure-transport properties in simulations of superconcentrated electrolyte.

Using molecular dynamics simulations and graph-theory-based cluster analysis, we investigate the structure-transport properties of typical water-in-salt electrolytes. We demonstrate that ions exhibit distinct dynamics across different ionic clusters-namely, solvent-separated ion pairs (SSIPs), contact ion pairs (CIPs), and aggregates (AGGs). We assess the average proportions of various ionic species and their lifetimes. Our method reveals a dynamic decoupling of ion kinetics, with each species independently contributing to the overall molecular motion. This is evidenced by the fact that the total velocity autocorrelation function (VACF) and power spectrum can be expressed as a weighted sum of independent functions for each species. The experimental data on the ionic conductivity of the studied LiTFSI electrolytes align well with our theoretical predictions at various concentrations, based on the proportions and diffusion coefficients of free ions derived from our analysis. The insights gained into the solvation structures and dynamics of different ionic species enable us to elucidate the physical mechanisms driving ion transport in such superconcentrated electrolytes, providing a comprehensive framework for the future design and optimization of electrolytes.

Research and Application of Deep Learning Selection Method for Magnetotelluric Power Spectrum Based on Rhoplus Correction

Magnetotelluric (MT) is an electromagnetic exploration method using natural field sources, which are unstable, irregular, and vulnerable to interference from electromagnetic signals. The total power spectrum of the magnetotelluric signal is superimposed by a sub-power spectrum of segmented time series. To reduce the influence of electromagnetic interference, the pre-processing of magnetotelluric data will delete the severely interfered sub-power spectrum. The selection of power spectrum often requires human-computer interaction, which is time-consuming and laborious, heavily dependent on personal experience, and has great randomness. This article innovation is put forward based on the classification of Rhoplus correction and deep learning automatic power spectrum method, first of all, the MT power spectrum impedance estimation results are Rhoplus one dimensional inversion and obtain fitting, using neural network learning fitting differential characteristics and classification, and then for the power spectrum of MT again after low-quality quantum power spectrum to eliminate overlay, Impedance estimation is performed, and the above process is repeated to find the optimal power spectrum combination. Through the comparison and verification of measured MT data, the automatic power spectrum selection method based on Rhoplus correction and deep learning classification achieve similar results to manual editing.

Predicting the impact of feedback on matter clustering with machine learning in CAMELS

ABSTRACT Extracting information from the total matter power spectrum with the precision needed for upcoming cosmological surveys requires unraveling the complex effects of galaxy formation processes on the distribution of matter. We investigate the impact of baryonic physics on matter clustering at z = 0 using a library of power spectra from the Cosmology and Astrophysics with MachinE Learning Simulations project, containing thousands of $(25\, h^{-1}\, {\rm Mpc})^3$ volume realizations with varying cosmology, initial random field, stellar and active galactic nucleus (AGN) feedback strength and subgrid model implementation methods. We show that baryonic physics affects matter clustering on scales $k \gtrsim 0.4\, h\, \mathrm{Mpc}^{-1}$ and the magnitude of this effect is dependent on the details of the galaxy formation implementation and variations of cosmological and astrophysical parameters. Increasing AGN feedback strength decreases halo baryon fractions and yields stronger suppression of power relative to N-body simulations, while stronger stellar feedback often results in weaker effects by suppressing black hole growth and therefore the impact of AGN feedback. We find a broad correlation between mean baryon fraction of massive haloes (M200c > 1013.5 M⊙) and suppression of matter clustering but with significant scatter compared to previous work owing to wider exploration of feedback parameters and cosmic variance effects. We show that a random forest regressor trained on the baryon content and abundance of haloes across the full mass range 1010 ≤ Mhalo/M⊙<1015 can predict the effect of galaxy formation on the matter power spectrum on scales k = 1.0–20.0 $h\, \mathrm{Mpc}^{-1}$.

SEMG Spectral Analysis and Machine Learning Algorithms Are Able to Discriminate Biomechanical Risk Classes Associated with Manual Material Liftings.

Manual material handling and load lifting are activities that can cause work-related musculoskeletal disorders. For this reason, the National Institute for Occupational Safety and Health proposed an equation depending on the following parameters: intensity, duration, frequency, and geometric characteristics associated with the load lifting. In this paper, we explore the feasibility of several Machine Learning (ML) algorithms, fed with frequency-domain features extracted from electromyographic (EMG) signals of back muscles, to discriminate biomechanical risk classes defined by the Revised NIOSH Lifting Equation. The EMG signals of the multifidus and erector spinae muscles were acquired by means of a wearable device for surface EMG and then segmented to extract several frequency-domain features relating to the Total Power Spectrum of the EMG signal. These features were fed to several ML algorithms to assess their prediction power. The ML algorithms produced interesting results in the classification task, with the Support Vector Machine algorithm outperforming the others with accuracy and Area under the Receiver Operating Characteristic Curve values of up to 0.985. Moreover, a correlation between muscular fatigue and risky lifting activities was found. These results showed the feasibility of the proposed methodology-based on wearable sensors and artificial intelligence-to predict the biomechanical risk associated with load lifting. A future investigation on an enriched study population and additional lifting scenarios could confirm the potential of the proposed methodology and its applicability in the field of occupational ergonomics.

A Cross-internal Linear Combination Approach to Probe the Secondary CMB Anisotropies: Kinematic Sunyaev–Zel’dovich Effect and CMB Lensing

We propose a cross-internal linear combination (cross-ILC) approach to measure the small-scale cosmic microwave background (CMB) anisotropies robustly against the contamination from astrophysical signals. In particular, we focus on the mitigation of systematics from cosmic infrared background (CIB) and thermal Sunyaev–Zel’dovich (tSZ) signals in kinematic Sunyaev–Zel’dovich (kSZ) power spectrum and CMB lensing. We show the cross-spectrum measurement between two CMB maps created by nulling the contributions from CIB (CIB-free map) and tSZ (tSZ-free map) to be robust for kSZ, as the approach significantly suppresses the total contribution of CIB and tSZ signals. Similarly, for CMB lensing, we use the approach introduced by Madhavacheril & Hill but with a slight modification by using the tSZ-free and CIB-free maps in the two legs of the quadratic estimator. By cross-correlating the CMB lensing map created using this technique with galaxy surveys, we show that the biases from both CIB and tSZ are negligible. We also compute the impact of unmodeled CIB/tSZ residuals on kSZ and cosmological parameters, finding the kSZ measured using the standard ILC to be significantly biased. The kSZ estimate from the cross-ILC remains less affected by CIB/tSZ, making it crucial for current and upcoming CMB surveys such as the South Pole Telescope (SPT), Simons Observatory (SO), and CMB-S4. With the cross-ILC approach, we find that the total kSZ power spectrum can be measured at very high significance in the coming years: 35σ by SPT, 22σ by SO, and 80σ by CMB-S4. Finally, we forecast constraints on the epoch of reionization using the kSZ power spectrum and find that the duration of reionization, currently unconstrained by Planck, can be constrained to = 1.5 or 0.5 depending on the choice of the prior on the optical depth to reionization. The data products and the associated codes can be downloaded from this link (https://github.com/sriniraghunathan/cross_ilc_methods_paper).

Adaptation of functional systems in different generations of Caucasians in the North-East of Russia

BACKGROUND: A substantial body of research has focused on adaptation of the new residents of the European and Asian Far North. However, these publications fail to address the changes occurring in successive generations of native Caucasians who migrated to the regions with harsh climatic conditions.
 AIM: To study functional adaptations exhibited by individuals born in the Magadan Region to various generations of Caucasians permanently living in the area.
 METHODS: A total of 1632 male volunteers, all students aged 181.1 years, and of Caucasian ethnicity, participated in this study. These individuals were either migrants or residents of Russia's North-East, born within the first to third generations. We investigated anthropometric characteristics, cardiohemodynamic parameters, and gas exchange to understand the adaptive readjustments that take place within the body's functional systems.
 RESULTS: Migrants and first-generation residents in the Magadan region experience constant stress and inadequate functioning of their cardiohemodynamic and energy exchange systems under extreme conditions. However, the third-generation subjects exhibited optimal performance of the cardiovascular system. Remarkably, the third-generation residents demonstrate an increased systolic volume at lower arterial pressure and lower total peripheral resistance. Furthermore, they had elevated proportion of the high frequency component and total power of the heart rhythm spectrum. This represents a new level of changed influence on the heart rhythm, as seen in the altered balance of its statistical and spectral wave characteristics. Moreover, the adaptability of the cardiovascular system to the harsh conditions of the North is reflected not only in the physiological indicators of the body but also in the integral structure of their correlations. This includes the magnitude and sign of the correlation coefficients and their significance.
 CONCLUSIONS: Our main findings suggest that adaptive changes in cardiohemodynamic and gas exchange exhibited by the migrants and several generations of residents of the Far North-East of Russia are directed to minimization of the total energy expenditure in functional systems. Additionally, the parasympathetic contribution increases fostering a novel interaction between the components of autonomic nervous regulation reflected by both qualitative and quantitative alterations in the structure and patterns of correlation clusters. These findings contribute to our understanding of the physiological mechanisms behind the morphofunctional readjustments of Caucasian men in the process of adaptation to the harsh climatic conditions of the Russian North-East.

Repurposing electroencephalogram monitoring of general anaesthesia for building biomarkers of brain ageing: an exploratory study

BackgroundElectroencephalography (EEG) is increasingly used for monitoring the depth of general anaesthesia, but EEG data from general anaesthesia monitoring are rarely reused for research. Here, we explored repurposing EEG monitoring from general anaesthesia for brain-age modelling using machine learning. We hypothesised that brain age estimated from EEG during general anaesthesia is associated with perioperative risk. MethodsWe reanalysed four-electrode EEGs of 323 patients under stable propofol or sevoflurane anaesthesia to study four EEG signatures (95% of EEG power <8–13 Hz) for age prediction: total power, alpha-band power (8–13 Hz), power spectrum, and spatial patterns in frequency bands. We constructed age-prediction models from EEGs of a healthy reference group (ASA 1 or 2) during propofol anaesthesia. Although all signatures were informative, state-of-the-art age-prediction performance was unlocked by parsing spatial patterns across electrodes along the entire power spectrum (mean absolute error=8.2 yr; R2=0.65). ResultsClinical exploration in ASA 1 or 2 patients revealed that brain age was positively correlated with intraoperative burst suppression, a risk factor for general anaesthesia complications. Surprisingly, brain age was negatively correlated with burst suppression in patients with higher ASA scores, suggesting hidden confounders. Secondary analyses revealed that age-related EEG signatures were specific to propofol anaesthesia, reflected by limited model generalisation to anaesthesia maintained with sevoflurane. ConclusionsAlthough EEG from general anaesthesia may enable state-of-the-art age prediction, differences between anaesthetic drugs can impact the effectiveness and validity of brain-age models. To unleash the dormant potential of EEG monitoring for clinical research, larger datasets from heterogeneous populations with precisely documented drug dosage will be essential.

Method for Determining Effective Frequency Range of Coherency Based on Seismic Energy

When using data recorded by dense instrument arrays to fit the coherency model of spatial variation of seismic ground motions, the selected frequency range may affect the fitting parameters, which also affects the synthesized time history of the ground motion field. In this study, the acceleration of the 5th and the 45th Earthquake of the SMART-1 array was selected. The Abrahamson and Loh models were used to perform the parameter fitting of the coherency for frequency ranges of 0–8, 0–16 and 0–24[Formula: see text]Hz, and the obtained results were different. The smaller the frequency range, the lower the fitted lagged coherency. The influence of frequency range on fitting parameters of Loh model is much greater than that of Abrahamson model. Based on the relative relationship of ground motion energy distribution in each frequency band represented by the power spectra, from the perspective of power spectrum energy, the energy ratio concept was introduced, i.e. the ratio of the power spectra for a specific frequency range to the total power spectra. Based on the energy ratio, a method for determining the effective frequency range of the coherency model was developed. Through the comparison and analysis of the horizontal-component acceleration of the SMART-1 array, it was found that when the frequency range was 0–5[Formula: see text]Hz, the energy ratio exceeded 95%, when the frequency range was 0–8[Formula: see text]Hz, the energy in the frequency band reached approximately 99% of the total energy. Therefore, it is recommended that when the parameters of the coherency model are fitted, the frequency corresponding to an energy ratio of 95% can be used as the effective frequency. Within this range, the contamination of high-frequency components on the fitting results is minimized.

Hybrid multi-fluid-particle simulations of the cosmic neutrino background

Simulation of the cosmic clustering of massive neutrinos is a daunting task, due both to their large velocity dispersion and to their weak clustering power becoming swamped by Poisson shot noise. We present a new approach, the multi-fluid hybrid-neutrino simulation, which partitions the neutrino population into multiple flows, each of which is characterised by its initial momentum and treated as a separate fluid. These fluid flows respond initially linearly to nonlinear perturbations in the cold matter, but slowest flows are later converted to a particle realisation should their clustering power exceed some threshold. After outlining the multi-fluid description of neutrinos, we study the conversion of the individual flows into particles, in order to quantify transient errors, as well as to determine a set of criteria for particle conversion. Assembling our results into a total neutrino power spectrum, we demonstrate that our multi-fluid hybrid-neutrino simulation is convergent to < 3% if conversion happens at z = 19 and agrees with more expensive simulations in the literature for neutrino fractions as high as Ω νh 2 = 0.005. Moreover, our hybrid-neutrino approach retains fine-grained information about the neutrinos' momentum distribution. However, the momentum resolution is currently limited by free-streaming transients excited by missing information in the neutrino particle initialisation procedure, which restricts the particle conversion to z ≳ 19 if percent-level resolution is desired.

Effect of autonomic dysfunction on the exocrine function of the pancreas in chronic pancreatitis

Background. The article evaluates the impact of autonomic dysfunction according to the heart rate variability data and the Spielberger-Khanin questionnaire on the exocrine function of the pancreas in chronic pancreatitis (CP). The aim is to evaluate the exocrine function of the pancreas depending on the heart rate variability and survey using the Spielberger-Khanin questionnaire. Materials and methods. One hundred outpatients with a diagnosis of CP who were treated in Ternopil healthcare institutions were examined. The presence of exocrine pancreatic insufficiency was determined by the level of fecal α-elastase. The psycho-emotional state was assessed using the Spielberger-Khanin questionnaire. Statistical and spectral indicators of heart rate variability were analyzed: the range of variation, the amplitude of the mode, stress index, indicator of activity of regulatory systems, total spectrum power, absolute and percentage values of very low frequency (VLF), low frequency (LF), high frequency power (HF), the LF/HF ratio. A correlation analysis was performed of the obtained heart rate variability data, the Spielberger-Khanin questionnaire data with the degree of exocrine pancreatic insufficiency in terms of the level of fecal α-elastase. Results. The average value of reactive anxiety on the Spielberger-Khanin questionnaire is 44.33±0.89, personal anxiety is 43.19±0.82, which corresponds to the upper limit of the moderate level. A negative correlation was found between these parameters and the level of fecal α-elastase (r=–0.482, p&lt;0.01, and r=–0.555, p&lt;0.01, respectively). Based on the heart rate variability of patients with CP, a tendency among them to sympathicotonia was detected, which was accompanied by a significant increase in the amplitude of the mode, stress index, the LF/HF ratio and a decrease in the range of variation compared to the control group. In contrast to the healthy individuals, the humoral-metabolic effect of heart rhythm regulation prevailed in those with CP (VLF— (48.66±1.21)%) and the share of the nervous component (LF— (31.69±0.67)%, HF— (19.65±0.75)%) decreased, there was a significant decrease in the total power of the spectrum compared to the control group (1546.25±44.18 versus 3155.65±211.38). The indicator of the activity of regulatory systems in patients with CP (6.91±0.12) was at the upper limit of the intense load of regulatory systems, which reflects a significant impairment of adaptation among them and reliably differs from the control level (3.90±0.31). A significant correlation was found between the total power of the spectrum, indicator of the activity of regulatory systems and the level of fecal α-elastase (r=0.511, p&lt;0.01, and r=–0.398, p&lt;0.01, respectively). Conclusions. During the study, it was found that with a deterioration in the psycho-emotional state (according to the data of the Spielberger-Khanin questionnaire), exocrine insufficiency of the pancreas in patients with CP increased: there was a correlation between the content of fecal α-elastase and the level of reactive and personal anxiety. Positive statistically significant correlations between the amplitude of the mode, stress index with the duration of the course of CP indicate compensatory activation of the sympathetic division of the autonomic nervous system. It was also proved that exocrine insufficiency (according to the content of fecal α-elastase) worsened with an increase in sympathicotonia (according to the stress index). Adecrease in the functional reserve in patients with СР was revealed: a significant decrease in the total power of the spectrum was found compared to that of the control group; against this background, there was a decrease in the adaptive potential, deterioration in the psycho-emotional state, which resulted in an increase in exocrine pancreatic insufficiency. The obtained data motivate to improve the generally accepted comprehensive therapy of patients with chronic pancreatitis with the additional inclusion in it of agents to stabilize the autonomic nervous system.

Muscle metaboreflex activation during hypercapnia modifies nonlinear heart rhythm dynamics, increasing the complexity of the sinus node autonomic regulation in humans.

Muscle metaboreflex activation during hypercapnia leads to enhanced pressive effects that are poorly understood while autonomic responses including baroreflex function are not documented. Thus, we assessed heart rate variability (HRV) that is partly due to autonomic influences on sinus node with linear tools (spectral analysis of instantaneous heart period), baroreflex set point and sensitivity with the heart period-arterial pressure transfer function and sequences methods, and system coupling through the complexity of RR interval dynamics with nonlinear tools (Poincaré plots and approximate entropy (ApEn)). We studied ten healthy young men at rest and then during muscle metaboreflex activation (MMA, postexercise muscle ischemia) and hypercapnia (HCA, PetCO2 = + 10mmHg from baseline) separately and combined (MMA + HCA). The strongest pressive responses were observed during MMA + HCA, while baroreflex sensitivity was similarly lowered in the three experimental conditions. HRV was significantly different in MMA + HCA compared to MMA and HCA separately, with the lowest total power spectrum (p < 0.05), including very low frequency (p < 0.05), low frequency (p < 0.05), and high frequency (tendency) power spectra decreases, and the lowest Poincaré plot short-term variability index (SD1): SD1 = 36.2ms (MMA + HCA) vs. SD1 = 43.1ms (MMA, p < 0.05) and SD1 = 46.1ms (HCA, p < 0.05). Moreover, RR interval dynamic complexity was significantly increased only in the MMA + HCA condition (ApEn increased from 1.04 ± 0.04, 1.07 ± 0.02, and 1.05 ± 0.03 to 1.10 ± 0.03, 1.13 ± 0.04, and 1.17 ± 0.03 in MMA, HCA, and MMA + HCA conditions, respectively; p < 0.01). These results suggest that in healthy young men, muscle metaboreflex activation during hypercapnia leads to interactions that reduce parasympathetic influence on the sinus node activity but complexify its dynamics.

Myocardial strain parameters and autonomic balance in various variants of the postinfarction course in patients receiving high-dose atorvastatin therapy

Aim. To study parameters of left ventricular (LV) strain and heart rate variability (HRV) in patients with ST-segment elevation myocardial infarction (STEMI) in various variants of postinfarction receiving high-dose atorvastatin therapy.Material and methods. The study included 96 patients with STEMI. All patients underwent two-dimensional speckle tracking echocardiography and 24-hour electrocardiographic monitoring with HRV analysis. The included individuals were divided into groups without pathological LV remodeling (R (-), n=57) and with pathological post-infarction LV remodeling (R (+), n=39), the criterion for which was an increase in end-diastolic and/or end-systolic volume &gt;20% and &gt;15%, respectively. Further, depending on the achievement of target low-density lipoprotein cholesterol (LDL-C) (1,5 mmol/l and/or a decrease of more than 50%), the following subgroups were identified: 17 (43,6%) people, who reached target LDL-C levels (group 1), 22 (56,4%) patients, who did not reach target LDL-C levels (group 2). Similar subgroups were identified in the R (-) group as follows: 28 (49,1%) people, who reached target LDL-C levels (group 3) and 29 (50,9%) people, who did not reach target LDL-C levels (group 4).Results. Starting from the 12th week of follow-up, worsening of global longitudinal (GLS), circumferential (GCS), and radial (GRS) strain (p&lt;0,01) was registered in group 2. In group 1, worsening of these parameters was registered only by the 48th week (p&lt;0,01). In group 3, an increase in GLS was revealed by the 48th week (p=0,001), GCS and GRS — by the 12th week (p&lt;0,05). In group 4, favorable changes were observed only in GLS and GCS by the 48th week (p&lt;0,01). A significant change in HRV parameters was observed in group 3. By the 48th week, there was an increase in temporal indicators (SDNN, SDNNi, SDANN, RMSSD, pNN50) (p&lt;0,0001) and total spectrum power (p=0,0001) due to an increase in all frequency indicators (p&lt;0,001), while the index of autonomic balance L/H decreased by 33% (p=0,002). In group 4, only SDNN, SDANN and pNN50 (p&lt;0,05), as well as the total spectrum power (p=0,001) increased, but no change in frequencies. According to intergroup analysis in the acute period of STEMI, group 4 patients had higher HRV than in group 3 (p&lt;0,05).Conclusion. High-dose atorvastatin therapy improves LV strain characteristics and autonomic balance during the rehabilitation period after STEMI.

Comparative Analysis of Complex Programs of Renewal Treatment of Patients with Chronic Pancreatitis

Aim: To conduct a comparative analysis of the dynamics of heart rate variability parameters in CP patients with autonomic dysfunction under the influence of the proposed complex treatment programs with the additional inclusion of the vegetative stabilizing agent memoplant and a combination of complex bioregulatory drugs. Materials and Methods: Statistical and spectral parameters of heart rate variability were analyzed in 69 patients with CP before and after outpatient treatment. Patients were divided into 3 groups of 23 patients with CP: group 1 – received conventional treatment (CT) according to the clinical diagnosis and the protocol proposed by the Ministry of Health of Ukraine (Order No. 638 of 10.09.2014); group 2 – CT enhanced with a course of the vegetative-stabilizing drug ginkgo biloba (memoplant); 3 group – CT with a course of memoplant and complex bioregulatory therapy (BRT): momordica compositum, traumeel S and neurexan according to the proposed scheme. Results: In group 1, the stress index (SI) decreased by 18.49%, p&lt;0.05, vegetative reactivity (VR) increased by 21.31%, p&lt;0.05, IARS decreased by 25.79%, p&lt;0.01. In group 2, a more significant decrease in sympathicotonia was observed: SI decreased by 38.17% (p&lt;0.01), mode amplitude (АМо) by 14.57% (p&lt;0.05), the range of variation (X) increased by 12.78% (p&lt;0.05); IARS decreased by 44.55 % (p&lt;0.01) to moderate tension. There was an increase in the total spectrum power (TP) (by 29.21%, p&lt;0.01) and components: LF increased by 37.03% (p&lt;0.01) relative to the initial level, HF by 64.01% (p&lt;0.01), VLF by 8.75% (p&lt;0.05). In patients of group 3, normalization of SI and АМо was observed (indicators decreased by 48.42% and 19.98%, p&lt;0.01), X increased by 17.35%, p&lt;0.01; The VR level did not differ significantly from the control (1.16±0.06 and 1.25±0.10, respectively). IARS decreased by 56.18% (p&lt;0.01); TP increased by 49.61% (p&lt;0.01), LF by 76.78% (p&lt;0.01), HF by 117.67% (p&lt;0.01), VLF by 8.41% (p&lt;0.05). Conclusions: In patients with CP, a higher efficiency of treatment programs with the inclusion of ginkgo biloba and complex bioregulatory therapy on the state of autonomic regulation was established compared to the generally accepted program in terms of spectral and statistical parameters of heart rate variability.

Analytic Approximations of Scattering Effects on Beam Chromaticity in 21‐cm Global Experiments

AbstractScattering from objects near an antenna produce correlated signals from strong compact radio sources in a manner similar to those used by the “Sea Interferometer” to measure the radio source positions using the fine frequency structure in the total power spectrum of a single antenna. These fringes or ripples due to correlated signal interference are present at a low level in the spectrum of any single antenna and are a major source of systematics in systems used to measure the global redshifted 21‐cm signal from the early universe. In the Sea Interferometer a single antenna on a cliff above the sea is used to add the signal from the direct path to the signal from the path reflected from the sea thereby forming an interferometer. This was used for mapping radio sources with a single antenna by Bolton and Slee in the 1950s. In this paper we derive analytic expressions to determine the level of these ripples and compare these results in a few simple cases with electromagnetic modeling software to verify that the analytic calculations are sufficient to obtain the magnitude of the scattering effects on the measurements of the global 21‐cm signal. These analytic calculations are needed to evaluate the magnitude of the effects in cases that are either too complex or take too much time to be modeled using software.