Power Spectral Index Research Articles

Intermediate inflation in a generalized non-minimal derivative coupling model

In this work, we consider intermediate inflation in the context of the generalized non-minimal derivative coupling (GNMDC) model. In the GNMDC model, inflation is driven by a canonical scalar field that is coupled not only to gravity but also to the derivative of the scalar field. The model introduces new dynamics and features during the inflationary epoch. We find inflationary solutions with a power law scalar field for the power law coupling function. Additionally, we determine the inflaton potential that generates intermediate expansion of the scale factor. We also discuss the background equations in the high friction limit and derive constraints on the parameters of our model. Furthermore, we investigate the cosmological perturbations in the slow roll approximation within the GNMDC model, and we calculate the scalar and tensor spectral index and the tensor-to-scalar ratio during intermediate inflation. We compare the results of this model with observational data that can be used to test the model using cosmic microwave background radiation data. Overall, we establish conditions for the inflaton potential that ensure the continuation of accelerated expansion during slow roll inflation. We numerically analyze the power spectrum and spectral index for scalar and tensor modes in intermediate inflation in the high friction limit, and we use Planck 2018 data to obtain constraints on the parameters of the model. We demonstrate that intermediate inflation in the GNMDC model is successful in evaluation and explanation of background and perturbation quantities using observational data.

Balance Control Impairments in Usher Syndrome.

To explore postural disability in Usher Syndrome (USH) patients using temporal posturographic analysis to better elucidate sensory compensation strategies of deafblind patients for posture control and correlate the Activities-specific Balance Confidence (ABC) scale with posturographic variables. Thirty-four genetically confirmed USH patients (11 USH1, 21 USH2, 2 USH 4) from the Otolaryngology Outpatient Clinic and 35 controls were prospectively studied using both classical and wavelet temporal analysis of center of pressure (CoP) under different visual conditions on static and dynamic platforms. The functional impact of balance was assessed with the ABC scale. Classical data in the spatial domain, Sensorial Organization Test, and frequency analysis of the CoP were analyzed. On unstable surfaces, USH1 had greater CoP surface area with eyes open (38.51 ± 68.67) and closed (28.14 ± 31.64) versus controls (3.31 ± 4.60), p < 0.001 and (7.37 ± 7.91), p < 0.001, respectively. On an unstable platform, USH consistently showed increased postural sway, with elevated angular velocity versus controls with eyes open (USH1 [44.94 ± 62.54]; USH2 [55.64 ± 38.61]; controls [13.4 ± 8.57]) (p = 0.003; p < 0.001) and closed (USH1 [60.36 ± 49.85], USH2 [57.62 ± 42.36]; controls [27.31 ± 19.79]) (p = 0.002; p = 0.042). USH visual impairment appears to be the primary factor influencing postural deficits, with a statistically significant difference observed in the visual Sensorial Organization Test ratio for USH1 (80.73 ± 40.07, p = 0.04) and a highly significant difference for USH2 (75.48 ± 31.67, p < 0.001) versus controls (100). In contrast, vestibular (p = 0.08) and somatosensory (p = 0.537) factors did not reach statistical significance. USH exhibited lower visual dependence than controls (30.31 ± 30.08) (USH1 [6 ± 11.46], p = 0.004; USH2 [8 ± 14.15], p = 0.005). The postural instability index, that corresponds to the ratio of spectral power index and canceling time, differentiated USH from controls on unstable surface with eyes open USH1 (3.33 ± 1.85) p < 0.001; USH2 (3.87 ± 1.05) p < 0.002; controls (1.91 ± 0.85) and closed USH1 (3.91 ± 1.65) p = 0.005; USH2 (3.92 ± 1.05) p = 0.045; controls (2.74 ± 1.27), but not USH1 from USH2. The canceling time in the anteroposterior direction in lower zone distinguished USH subtypes on stable surface with optokinetic USH1 (0.88 ± 1.03), USH2 (0.29 ± 0.23), p = 0.026 and on unstable surface with eyes open USH1 (0.56 ± 1.26), USH2 (0.072 ± 0.09), p = 0.036. ABC scale could distinguish between USH patients and controls, but not between USH subtypes and it correlated with CoP surface area on unstable surface with eyes open only in USH1(ρ = 0.714, p = 0.047). USH patients, particularly USH1, exhibited poorer balance control than controls on unstable platform with eyes open and appeared to rely more on proprioceptive information while suppressing visual input. USH2 seems to use different multisensory balance strategies that do not align as well with the ABC scale. The advanced analysis provided insights into sensory compensation strategies in USH subtypes.

Extraction of periodic signals in Global Navigation Satellite System (GNSS) vertical coordinate time series using the adaptive ensemble empirical modal decomposition method

Abstract. Empirical modal decomposition (EMD) is an efficient tool for extracting a signal from stationary or non-stationary time series and is enhanced in stability and robustness by ensemble empirical mode decomposition (EEMD). Adaptive EEMD further improves computational efficiency through adaptability in the white noise amplitude and set average number. However, its effectiveness in the periodic signal extraction in Global Navigation Satellite System (GNSS) coordinate time series regarding the inevitable missing data and offset issues has not been comprehensively validated. In order to thoroughly investigate their impacts, we simulated 5 years of daily time series data with different missing data percentages or a different number of offsets and conducted them 300 times for each simulation. The results show that high accuracy could reach the overall random missing rate below 15 % and avoid consecutive misses exceeding 30 d. Meanwhile, offsets should be corrected in advance regardless of their magnitudes. The analysis of the vertical components of 13 stations within the Australian Global Sea Level Observing System (GLOSS) monitoring network demonstrates the advantage of adaptive EEMD in revealing the time-varying characteristics of periodic signals. From the perspectives of correlation coefficients (CCs), root mean square error (RMSE), power spectral density indices (κ) and signal-to-noise ratio (SNR), the means for adaptive EEMD are 0.36, 0.81, −0.18 and 0.48, respectively, while for least squares (LS), they are 0.27, 0.86, −0.50 and 0.23. Meanwhile, a significance test of the residuals further substantiates the effectiveness in periodic signal extraction, which shows that there is no annual signal remaining. Also, the longer the series, the higher the accuracy of the reasonable extracted periodic signal concluded via the significance test. Moreover, driving factors are more effectively facilitated by the time-varying periodic characteristics compared with the constant periodic signal derived by LS. Overall, the application of adaptive EEMD could achieve high accuracy in analyzing GNSS time series, but it should be based on properly dealing with missing data and offsets.

A rotary trans-osseous ultrasound blood flow detection method for endoscopic application

Due to the small size and proximity to the spinal cord and vertebral artery, the cervical pedicle screw fixation procedure remains to be challenging in clinical practice. The screw misplacement has a high probability of occurrence of severe complications. How to prevent direct injury to the vertebral artery is a vital study focus in cervical spine surgery. In this work, a trans-osseous ultrasound Doppler method is proposed to explore the possibility of detecting blood flow through thin cortical bone. A miniature single-element prototype probe with a center frequency of 2.5 MHz is prepared. With the classical pulse-echo acquisition, a Spectral Power Index (SPI) algorithm based on Spectral Doppler and sliding window traversal is designed to enhance the Doppler signal intensity. In vitro and in vivo experiments were conducted to investigate the feasibility of this method. The results of in vitro experiments suggest that the anticoagulated bovine blood flowing at a mean velocity of 15 cm/s to 80 cm/s is detectable when the thickness of cortical bone is 0.7 ± 0.1 mm. The in vivo experiment showed that the large blood vessel with a diameter of about 3 mm (radial artery) can be detected through thin cortical bone (thickness of 0.7 ± 0.1 mm). The proposed trans-osseous Doppler method achieves artery detection through thin cortical bone, which has demonstrated the possibility of intraoperative vessel pre-warning. The present study poses a promising strategy to reduce the risk of vertebral artery injury and misalignment rate in the cervical pedicle screw insertion procedure.

Effects of Vortioxetine on Sleep Architecture of Adolescents with Major Depressive Disorder.

The relationship between depression and insomnia is bidirectional and both conditions need to be treated adequately, especially in a vulnerable neurodevelopmental stage of adolescence. This study aimed to evaluate the effects of antidepressant treatment using vortioxetine (VOR) on the sleep architecture of depressed adolescents by using video-polysomnography (v-PSG), which has not been researched before. The v-PSG was performed on 30 adolescent in-patients (mean age of 15.0 years ± 1.5 SD, 21 girls) treated with VOR (dosage of 10/15/20 mg/day) administered orally once a day, before and after VOR treatment. The evaluated parameters were conventional sleep parameters, sleep fragmentation parameters, and selected spectral power indices. Symptoms of depression and insomnia before and after the treatment period were evaluated using valid and reliable questionnaires (the Children´s Depression Inventory and the Athens Insomnia Scale). Depressed adolescents showed higher REM latency and decreased REM sleep percentage after treatment than before the treatment period (p = 0.005, p = 0.009, respectively). Our study revealed REM suppression (increased REM latency and reduced REM sleep percentage), indicating altered sleep architecture as a potential result of VOR treatment, which seems to be dose-dependent.

BIOLOGICAL AND SOCIAL ASPECTS OF HUMAN HEALTH AS DETERMINANTS OF ECONOMIC DEVELOPMENT

The purpose of the study was to analyse the relationship between a person's mental performance, work efficiency and psychophysiological functions (PF) of the body. It is proved that taking into account the biological foundations of a person should be an essential condition for life and health, as well as for the development of a modern democratic country. The use of a typological approach based on psychophysiological criteria optimises professional orientation and provides recommendations on the possibility of mastering certain professions without harming health. This approach contributes to the efficient allocation of human capital, the use of periodic health monitoring, and the prediction of production volumes and quality, as well as its competitiveness. Methodology. The study was aimed at identifying the level of mental performance and efficiency of information processing on a computer in representatives of three groups of employees who differed in strength (mental performance, MP), mobility of nervous processes (MNP), balance (BNP) of nervous processes, speed of sensorimotor reactivity, indicators of situational anxiety (SA), cardiovascular system, and activation processes of the brain. Results. The study found that the examined employees of an office company (77 women and men aged 18-23 years) who had the highest level of MP and work efficiency were characterised by higher heart rate spectral power (HR), SA, and BNP. It is from individuals of this psychophysiological type that one should expect maximum mastery of the profession, relevant competencies associated with the speed of reaction, a minimum of erroneous actions, promotion of income, production volumes and rates, and a low level of injuries. The group of employees with low levels of PF was characterised by low levels of MP and efficiency, but at the same time high levels of SA, demonstrating a high risk of chronic fatigue and general neuroticism. In order to optimise the professional sphere and increase the economic income of this category of people, it is recommended that they be more careful in selecting professions that have a less intensive rhythm of work and a low stress component. Subjects with an average level of sensorimotor reactivity, spectral power indices of HR, SA and BNP showed a high level of RP and work efficiency, but relatively low reserve capabilities of the body. In this case, to prevent a decline in health, deterioration in the quality of life, labour productivity and economic decline, a clear distribution of occupational loads and rest should be followed. Practical implications. Taking into account that the respondents with the highest spectral power indicators of HR, SA, and BNP showed the highest level of MP and efficiency of work performed, it is this category that should be targeted first of all by the main business strategies of the country's development related to economic growth, development of marketing trajectories, and building innovative and exclusive production models. At the same time, it is necessary to systematically introduce various health-saving programmes to enable timely restoration of human physical and psychophysiological potential. Subjects with low characteristics of the psycho-emotional and neurovegetative spheres demonstrated lower MP and work efficiency. Predictably, they are associated with lower ratings of competitiveness and income in a professional field with a high rhythm of tasks, tension and time pressure, but are able to demonstrate sufficient labour potential in other professions. Value/originality. The obtained actual data of the selected groups of employees make it possible to assess the MP, the effectiveness of the work performed by them and can be used as reliable biological markers of economic fluctuations in society. On the other hand, it should be borne in mind that high performance and labour efficiency largely depend on the PFs involved in the state of human health. Thus, timely preservation and maintenance of the population's health at the proper level, combined with the applied typological psychophysiological approach to vocational guidance and individualisation of work regimes, lays a solid foundation for the economic growth of a democratic country.

Effect of intermittent structures on the spectral index of the magnetic field in the slow solar wind

Abstract. Intermittent structures are ubiquitous in the solar wind turbulence, and they can significantly affect the power spectral index (which reflects the cascading process of the turbulence) of magnetic field fluctuations. However, to date, an analytical relationship between the intermittency level and the magnetic spectral index has not been shown. Here, we present the continuous variation in the magnetic spectral index in the inertial range as a function of the intermittency level. Using the measurements from the Wind spacecraft, we find 42 272 intervals with different levels of intermittency and with a duration of 5–6 min from 46 slow-wind streams between 2005 and 2013. Among them, each of the intermittent intervals is composed of one dominant intermittent structure and background turbulent fluctuations. For each interval, a magnetic spectral index αB is determined for the Fourier spectrum of the magnetic field fluctuations in the inertial range between 0.01 and 0.3 Hz. A parameter Imax, which corresponds to the maximum of the trace of the partial variance increments of the intermittent structure, is introduced as an indicator of the intermittency level. Our statistical result shows that, as Imax increases from 0 to 20, the magnetic spectrum becomes gradually steeper and the magnetic spectral index αB decreases from −1.63 to −2.01. Accordingly, for the first time, an empirical relation is established between αB and Imax: αB=0.4exp⁡(-Imax/5)-2.02. The result will help us to uncover more details about the contributions of the intermittent structures to the magnetic power spectra and, furthermore, about the physical nature of the energy cascade taking place in the solar wind. It will also help to improve turbulence theories that contain intermittent structures.

Machine Learning Techniques Reveal Aberrated Multidimensional EEG Characteristics in Patients with Depression.

Depression has become one of the most common mental illnesses, causing serious physical and mental harm. However, there remain unclear and uniform physiological indicators to support the diagnosis of clinical depression. This study aimed to use machine learning techniques to investigate the abnormal multidimensional EEG features in patients with depression. Resting-state EEG signals were recorded from 41 patients with depression and 34 healthy controls. Multiple dimensional characteristics were extracted, including power spectral density (PSD), fuzzy entropy (FE), and phase lag index (PLI). These three different dimensional characteristics with statistical differences between two groups were ranked by three machine learning algorithms. Then, the ranked characteristics were placed into the classifiers according to the importance of features to obtain the optimal feature subset with the highest classification accuracy. The results showed that the optimal feature subset contained 86 features with the highest classification accuracy of 98.54% ± 0.21%. According to the statistics of the optimal feature subset, PLI had the largest number of features among the three categories, and the number of beta features was bigger than other rhythms. Moreover, compared to the healthy controls, the PLI values in the depression group increased in theta and beta rhythms, but decreased in alpha1 and alpha2 rhythms. The PSD of theta and beta rhythms were significantly greater in depression group than that in healthy controls, and the FE of beta rhythm showed the same trend. These findings indicate that the distribution of abnormal multidimensional features is potentially useful for the diagnosis of depression and understanding of neural mechanisms.

Observational connection of non-thermal X-ray emission from pulsars with their timing properties and thermal emission

ABSTRACTThe origin and radiation mechanisms of high-energy emissions from pulsars have remained mysterious since their discovery. Here we report, based on a sample of 68 pulsars, observational connection of non-thermal X-ray emissions from pulsars with their timing properties and thermal emissions, which may provide some constraints on theoretical modeling. Besides strong correlations with the spin-down power $\dot{E}$ and the magnetic field strength at the light cylinder Blc, the non-thermal X-ray luminosity in 0.5–8 keV, Lp, represented by the power-law component in the spectral model, is found to be strongly correlated with the highest possible electric field strength in the polar gap, Epc, of the pulsar. The spectral power index Γp of that power-law component is also found, for the first time in the literature, to strongly correlate with $\dot{E}$, Blc, and Epc, thanks to the large sample. In addition, we found that Lp can be well described by Lp ∝ T5.96 ± 0.64R2.24 ± 0.18, where T and R are the surface temperature and the emitting-region radius of the surface thermal emission, represented by the blackbody component in the spectral model. Γp, on the other hand, can be well described only when timing variables are included and the relation is $\Gamma _{\rm p}= \log (T^{-5.8\pm 1.93}R^{-2.29\pm 0.85}P^{-1.19\pm 0.88}\dot{P}^{0.94\pm 0.44})$ plus a constant. These relations strongly suggest the existence of connections between surface thermal emission and electron–positron pair production in pulsar magnetospheres.

Predicting acute termination and non-termination during ablation of human atrial fibrillation using quantitative indices.

Background: Termination of atrial fibrillation (AF), the most common arrhythmia in the United States, during catheter ablation is an attractive procedural endpoint, which has been associated with improved long-term outcome in some studies. It is not clear, however, whether it is possible to predict termination using clinical data. We developed and applied three quantitative indices in global multielectrode recordings of AF prior to ablation: average dominant frequency (ADF), spectral power index (SPI), and electrogram quality index (EQI). Methods: In N = 42 persistent AF patients (65 ± 9 years, 14% female) we collected unipolar electrograms from 64-pole baskets (Abbott, CA). We studied N = 17 patients in whom AF terminated during ablation ("Term") and N = 25 in whom it did not ("Non-term"). For each index, we determined its ability to predict ablation by computing receiver operating characteristic (ROC) and calculated the area under the curve (AUC). Results: The ADF did not differ for Term and Non-term patients at 5.28 ± 0.82 Hz and 5.51 ± 0.81 Hz, respectively (p = 0.34). Conversely, the SPI for these two groups was. 0.85 (0.80-0.92) and 0.97 (0.93-0.98) and the EQI was 0.61 (0.58-0.64) and 0.56 (0.55-0.59) (p < 0.0001). The AUC for predicting AF termination for the SPI was 0.85 ([0.68, 0.95] 95% CI), and for the EQI, 0.86 ([0.72, 0.95] 95% CI). Conclusion: Both the EQI and the SPI may provide a useful clinical tool to predict procedural ablation outcome in persistent AF patients. Future studies are required to identify which physiological features of AF are revealed by these indices and hence linked to AF termination or non-termination.

Unifying turnaround-bounce cosmology in a cyclic universe considering a running vacuum model

Among many models which can describe the bouncing cosmology, a matter bounce scenario that is deformed by a running vacuum model of dark energy (RVM-DE) has been interested. In this research, I show that a class of RVM-CDM (cold dark matter) model can also describe a cyclical cosmology in which the universe undergoes cycles of expansion to the contraction phase and vice versa. To this end, following our previous work, I consider one of the most successful classes of RVM-CDM model in bouncing cosmology, [Formula: see text], in which the power spectral index gets a red tilt and the running of the spectral index may give a negative value by choosing the appropriate value of parameters [Formula: see text], [Formula: see text], [Formula: see text], which is consistent with the cosmological observations. It is worthwhile to mention that most matter bounce models do not produce this negative value. However, the main purpose of this paper is to investigate the RVM-CDM model in the turnaround phase. Far from the bounce in a phantom expanding universe, the turnaround conditions are investigated before the occurrence of a sudden big rip. By analyzing the Hubble parameter, equation of state (EoS) parameter, and deceleration parameter around the turnaround, we show that a successful turnaround may occur after an expansion in an interacting case of RVM-CDM by choosing the appropriate value of parameters. A minimum value for the interaction parameter is obtained and also find any relation between other model parameters. Finally, the effect of each parameter on a turnaround is studied, and we see that the transition time from accelerating to decelerating expansion can occur earlier for larger values of interaction parameter. Also, in several graphs, the effect of the second term in DE density, including [Formula: see text], is studied, and we see that by increasing its coefficient, [Formula: see text], the transition point leads to lower values.

Inflation with antisymmetric tensor field: new candidates

We study classes of inflation models driven by antisymmetric tensor field, with minimal and nonminimal couplings to gravity, that address the known issues of such models considered in the past. First, we show that with a different choice of the background structure of the antisymmetric tensor field, inflation is supported even for the minimal model with quadratic potential contrary to past results. We also include the nonminimal coupling to gravity and analyse perturbations to the antisymmetric tensor as well as the tensor modes of perturbed metric. The two models differ in terms of the behaviour of tensor modes, where the speed of the gravitational wave can be tuned to c in the latter model. The power spectrum and spectral index receive slight scale dependence. Finally, we consider a quartic potential motivated by the graceful exit to reheating phase, which requires a nonminimal coupling to support inflation. The two tensor modes of the perturbed metric are found to evolve differently in this model, and give rise to a highly scale-dependent power spectrum.

A New Index for Detecting Frequency of Unknown Underwater Weak Signals with Genetic Algorithm

In this paper, a new index is proposed for detecting the frequency of unknown underwater signals based on the stochastic resonance theory. When the received weak signal is input into the stochastic resonance system, first, by frequency analysis, the frequency with the highest amplitude Aₘ of the output signal spectrum is considered as the pre-detection fre-quency. Then a cosine signal with the pre-detection frequency and unit amplitude is constructed. Define the pre-signal-to-noise-ratio as the logarithm of the squared amplitude Aₘ over the mean of signal amplitudes in all other frequencies. The new index is defined as the product of the pre-signal-to-noise-ratio and the correlation coefficient between the received unknown signal and the constructed cosine signal. The new index is featured by taking into account the signal characteristics in both time and frequency domain, and it will yield better signal frequency detection performance. In addition, to improve the time efficiency of the frequency detection, a method to bound the searching range, keyed to the genetic algorithm, of the stochastic resonance system parameters is proposed. The method can be used to detect the frequency of both single frequency and frequency-hopping unknown signals. With the designed new index and system parameter bounding method, the simulations and experiments for the weak underwater unknown signals are conducted. Compared to the piecewise mean value index and weighted power spectral kurtosis index, the new index yields a higher detection probability at varied input signal-to-noise ratios and signal frequencies. With bounding system parameter searching ranges, the time efficiency is improved. The main purpose of this paper is to detect the frequency of unknown underwater weak signals by stochastic resonance system with genetic algorithm. The main contributions are summarized as follows. First, the detection probability of weak signals is improved by stochastic resonance system with the proposed signal detection index than some other indexes. Second, to improve the time efficiency of the signal frequency detection, a method to bound the searching range of system parameters is proposed.

Insomnia subtypes characterised by objective sleep duration and NREM spectral power and the effect of acute sleep restriction: an exploratory analysis

Insomnia disorder (ID) is a heterogeneous disorder with proposed subtypes based on objective sleep duration. We speculated that insomnia subtyping with additional power spectral analysis and measurement of response to acute sleep restriction may be informative in overall assessment of ID. To explore alternative classifications of ID subtypes, insomnia patients (n = 99) underwent two consecutive overnight sleep studies: (i) habitual sleep opportunity (polysomnography, PSG) and, (ii) two hours less sleep opportunity (electroencephalography, EEG), with the first night compared to healthy controls (n = 25). ID subtypes were derived from data-driven classification of PSG, EEG spectral power and interhemispheric EEG asymmetry index. Three insomnia subtypes with different sleep duration and NREM spectral power were identified. One subtype (n = 26) had shorter sleep duration and lower NREM delta power than healthy controls (short-sleep delta-deficient; SSDD), the second subtype (n = 51) had normal sleep duration but lower NREM delta power than healthy controls (normal-sleep delta-deficient; NSDD) and a third subtype showed (n = 22) no difference in sleep duration or delta power from healthy controls (normal neurophysiological sleep; NNS). Acute sleep restriction improved multiple objective sleep measures across all insomnia subtypes including increased delta power in SSDD and NSDD, and improvements in subjective sleep quality for SSDD (p = 0.03), with a trend observed for NSDD (p = 0.057). These exploratory results suggest evidence of novel neurophysiological insomnia subtypes that may inform sleep state misperception in ID and with further research, may provide pathways for personalised care.

Effect of long-term training on heart rate variability, central hemodynamics and physical working capacity in female swimmers with different sports qualifications

The aim of this study was to compare the indices of heart rate variability, central hemodynamics and physical working capacity in female swimmers with different sports qualifications. Materials and methods. The indices of heart rate variability (HRV), central hemodynamics (CH) and physical development (PD) were studied in 44 female swimmers (mean age 15.00 ± 0.36 years, swimming experience – 7.40 ± 0.35 years) depending on their sports qualifications (MSIC, MS, CMS, first- and second-class athletes). To analyze the autonomic regulation of cardiac activity, power spectral and time-domain indices of HRV were used. CH were examined by the method of automated tetrapolar rheography according to W. Kubiček et al. (1970) in Y. T. Pushkar’s et al. modification (1970). Physical working capacity was measured according to the generally accepted technique on a cycling ergometer using the PWC170 submaximal test. The functional state index (FSI) was calculated using the formula patented by authors. Results. Significant differences were found between the indices of HRV, CH and PD in female swimmers with different qualifications. Thus, in the athletes with the MSIC–MS sports qualifications, heart rate was 61.0 ± 3.8 bpm, cardiac index (CI) – 2.978 ± 0.098 L·min-1·m-2 (there was a trend towards the eukinetic type of hemodynamics (TH)), stress index (SI) – 51.16 ± 12.66 relative units (r.u.), PWC170/kg – 16.98 ± 1.22 kgm·min-1·kg-1, FSI – 6.511 ± 0.422 r.u. A decrease in heart rate among them was correlated with a decrease in SI, and an increase in Mo – with a decrease in CI. In female CMS swimmers, heart rate was 61.37 ± 2.83 beats/min-1, CI – 3.021 ± 0.112 l -1min -1·m -2 , a trend towards the predominantly eukinetic TH, SI – 53.73 ± 9.41 r.u., PWC170 /kg– 14.66 ± 0.683 kgm·min-1·kg -1, FSI – 5.683 ± 0.324 r.u. Reduced values of SI and CI were associated with increased values of Mo and PWC170/kg. In first- and second-class female swimmers, heart rate was 63.05 ± 2.22 beats/min, SI – 50.62 ± 6.4 r.u. This group tended to be eytonic and eukinetic. The mean value of the PWC170/kg was 14.19 ± 0.589 kgm·min-1·kg-1 and FSI – 5.953 ± 0.337 r.u. Correlation analysis confirmed the relationship between the decrease in heart rate and CI and the increase in Mo and PWC170/kg. Conclusions. Long-term training in female swimmers at the distance of 50 to 200 meters is accompanied by the significant increase in the PWC170/kg values with qualification improving, 14.19 ± 0.589 kgm·min-1·kg-1, 14.66 ± 0.683 kgm·min-1·kg-1; 16.98 ± 1.22 kgm·min-1·kg-1, respectively, improvements in HRV (decrease in stress index and increase in Mo) and decrease in CI.

On the prevalence of flow instabilities from high-fidelity computational fluid dynamics of intracranial bifurcation aneurysms

High-fidelity computational fluid dynamics (HF-CFD) has revealed the potential for high-frequency flow instabilities (aka “turbulent-like” flow) in intracranial aneurysms, consistent with classic in vivo and in vitro reports of bruits and/or wall vibrations. However, HF-CFD has typically been performed on limited numbers of cases, often with unphysiological inflow conditions or focused on sidewall-type aneurysms where flow instabilities may be inherently less prevalent. Here we report HF-CFD of 50 bifurcation aneurysm cases from the open-source Aneurisk model repository. These were meshed using quadratic finite elements having an average effective spatial resolution of 0.065 mm, and solved under physiologically-pulsatile flow conditions using a well-validated, minimally-dissipative solver with 20,000 time-steps per cardiac cycle Flow instability was quantified using the recently introduced spectral power index (SPI), which quantifies, from 0 to 1, the power associated with velocity fluctuations above those of the driving inflow waveform. Of the 50 cases, nearly half showed regions within the sac having SPI up to 0.5, often with non-negligible power into the 100's of Hz, and roughly 1/3 had sac-averaged SPI > 0.1. High SPI did not significantly predict rupture status in this cohort. Proper orthogonal decomposition of cases with highest SPIavg revealed time-varying energetics consistent with transient turbulence. Our reported prevalence of high-frequency flow instabilities in HF-CFD modelling of aneurysms suggests that care must be taken to avoid routinely overlooking them if we are to understand the highly dynamic mechanical forces to which some aneurysm walls may be exposed, and their prevalence in vivo.

Implications of a possible TeV break in the cosmic-ray electron and positron flux

A TeV spectral break in the total flux of cosmic-ray electrons and positrons (CREs) at which the spectral power index softens from $\ensuremath{\sim}3$ to $\ensuremath{\sim}4$ has been observed by H.E.S.S. and recently confirmed by DAMPE with a high significance of $6.6\ensuremath{\sigma}$. Such an observation is apparently inconsistent with the data from other experiments such as Fermi-LAT, AMS-02, and CALET. We perform a global analysis on the latest CRE data including Fermi-LAT, AMS-02, CALET, DAMPE, and H.E.S.S., with energy scale uncertainties taken into account to improve the consistency between the datasets. The fit result strongly favors the existence of the break at $\ensuremath{\sim}1\text{ }\text{ }\mathrm{TeV}$ with an even higher statistical significance of $13.3\ensuremath{\sigma}$. In view of the tentative CRE break, we revisit a number of models of nearby sources, such as a single generic pulsar wind nebula (PWN), known multiple PWNe from the ATNF catalog, and their combinations with either an additional dark matter (DM) component or a supernova remnant (SNR). We show that the CRE break at $\ensuremath{\sim}1\text{ }\text{ }\mathrm{TeV}$, together with the known CR positron excess, points towards the possibility that the nearby sources should be highly charge asymmetric. Among the models under consideration, the one with a PWN plus a SNR is the most favored by the current data. The favored distances and ages of the PWN and SNR sources are both within 0.6 kpc and around ${10}^{5}\text{ }\text{ }\mathrm{yr}$, respectively. Possible candidate sources include PSR J0954-5430, Vela and the Monogem ring, etc. We find that for the models under consideration, the additional DM component is either unnecessary or predicts too much photon emission in tension with the H.E.S.S. data of $\ensuremath{\gamma}$-rays from the direction of the Galactic Center. We also show that the current measurement of the anisotropies in the arrival direction of the CRE can be useful in determining the properties of the sources.

A Perspective on the Scaling of Magnetosheath Turbulence and Effects of Bow Shock Properties

Abstract We analyze magnetic field data from two magnetosheath crossings, representative of a larger collection of similar cases in the database of the Cluster spacecraft. We apply a novel data analysis method to identify the power-law behavior of the structure functions and to find the validity range of the power-law scaling. We validate the technique with solar wind magnetic field data and a synthetic magnetic field signal. This approach grants a rigorous determination of the scale range for a linear fit of the structure function in the log–log representation, which most often is chosen arbitrarily. The fitting allows an estimation of the power spectral index from the scale variation of the second-order structure function exponent. Data recorded during the first Cluster magnetosheath crossing, called Event 1, indicate three different power-law scaling regimes (injection, inertial, and kinetic) separated by two spectral breaks, consistent with the scenario of fully developed turbulence. However, data from the second Cluster magnetosheath crossing, called Event 2, depict a different scenario with only two power-law scaling regimes determined from the fit. A spectral slope shallower than the Kolmogorovian solar wind power-law index is determined at magnetohydrodynamic scales, spanning more than three frequency decades, which is separated by a spectral break from the kinetic regime. An analysis of simultaneous solar wind data from the Advanced Composition Explorer suggests that the scale behavior of the magnetosheath fluctuations might be controlled by the structure of the bow shock; solar wind turbulent fluctuations are only partially destroyed while they are carried across the bow shock. Both events are recorded in a quasi-perpendicular magnetosheath.

Analysis on Food Crispness Based on Time and Frequency Domain Features of Acoustic Signal

Crispness is an important indicator of crunchy food. However, it cannot be easily quantified by sensory evaluation, due to the high subjectivity of evaluators; instrument measurement of this indicator requires much manpower and time. To improve the efficiency of food crispness prediction, this paper attempts to build a rapid, convenient, and accurate crispness analysis model. Starting with the fracturing sound of crunchy food, the authors collected the fracturing acoustic signal, conducted wavelet denoising, analyzed the eigenvalues in time and frequency domains, and constructed crispness prediction models based on multiple linear regression (MLR) and neural network, respectively. Through fracturing test and acoustic test, cluster analysis was adopted to select the typical eigenvalues of acoustic signal, including the peak amplitude of power spectral density (PSD) curve, amplitude difference, and waveform index. Based on these eigenvalues, a crispness analysis model was established, and used to predict the crispness of four kinds of food, namely, potato, sweet potato, carrot, and turnip. The results show that the BP neural network had a smaller relative error than the MLR; when the threshold was 5%, the BP neural network maintained a prediction accuracy of &gt;90%, and achieved 100% prediction accuracy on two types of food. To sum up, this paper reveals the relationship between the food chewing sound features and food quality, laying the theoretical basis for the research of food chewing sound mechanism.

High-frequency semicircular canal deficit affects postural control in hearing-impaired children

ObjectivesThe present study aimed to analyse the impact of vestibulo-ocular reflex (VOR) gain deficit on postural control (PC) in children with sensorineural hearing loss. MethodsA retrospective study included 55 children with sensorineural hearing loss between 4 and 17 years of age. The Video Head Impulse Test (vHIT®) was used to assess semicircular canal function. PC was assessed on the Balance Quest® posturographic platform testing sensory organisation. ResultsSpatial and temporal postural parameters (area and mean speed of centre of pressure oscillation, spectral power index) in the OKN-U condition (optokinetic with unstable platform) were significantly better in children with than without VOR deficit. ConclusionPosturographic exploration in the OKN-U condition can screen for semicircular canal deficit in hearing-impaired children. VOR deficit also seems to predict PC deficit.