Low Frequency Ratio Research Articles

Dual-Band Dual-Polarized Patch Antenna Using Characteristic Mode Analysis

In this research, a novel dual-band triangular patch antenna (TPA) with linear-orthogonal polarization is designed by utilizing degenerate modes (DMs). Current symmetries of fundamental DMs of TPA are exploited to achieve dual-band antenna operation. An equilateral triangular slot is inserted along one of the edges to separate resonant frequencies of DMs and simultaneously exciting them at different resonant frequencies. The location of the slot is chosen according to the current symmetries of the horizontal mode to elongate its current paths and moving it to a lower resonant frequency while keeping vertical mode at its fundamental resonant frequency. The prototype of the proposed single probe-fed antenna is fabricated and tested. The designed antenna exhibits low frequency ratio (FR) and broadside radiation patterns with gains of 4.96 and 6.10 dBi in the first and second bands, respectively. Low cross-polarization levels and linear-orthogonal polarization are achieved in both bands.

Experimental and numerical evaluation on debonding of fully grouted rockbolt under pull-out loading

The axial loading in rockbolts changes due to stress redistribution and rheology in the country rock mass. Such a change may lead to debonding at rockbolt to grout interface or rupture of the rockbolt. In this study, based on laboratory experiments, ultrasonic guided wave propagation in fully grouted rockbolt under different pull-out loads was investigated in order to examine the resultant debonding of rockbolt. The signals obtained from the ultrasonic monitoring during the pull-out test were processed using wavelet multi-scale analysis and frequency spectrum analysis, the signal amplitude and the amplitude ratio (Q) of low frequency to high frequency were defined to quantify the debonding of rockbolt. In addition to the laboratory test, numerical simulation on the effect of the embedment lengths on ultrasonic guided wave propagation in rockbolt was conducted by using a damage-based model, and the debonding between rockbolt and cement mortar was numerically examined. It was confirmed that the ultrasonic guided wave propagation in rockbolt was very sensitive to the debonding because of pull-out load, therefore, the critical bond length could be calculated based on the propagation of guided wave in the grouted rockbolt. In time domain, the signal amplitude in rockbolt increased with pull-out load from 0 to 100 kN until the completely debonding, thus quantifying the debonding under the different pull-out loads. In the frequency domain, as the Q value increased, the debonding length of rockbolt decreased exponentially. The numerical results confirmed that the guided wave propagation in the fully grouted rockbolt was effective in detecting and quantifying the debonding of rockbolt under pull-out load.

Dual-Band Dual-Linearly/Circularly polarized Shared-Aperture antenna for satellite communication systems

This paper presents a dual-band dual-linear/circular-polarization shared-aperture antenna for satellite communication. The antenna has dual linear polarization (DLP) radiation performance in K-band and dual circular polarization (DCP) radiation performance in Ka-band. The four radiation patches cut by two slots in the linear polarization structure form a 2 × 2 circular polarization array. By cleverly combining DLP and DCP radiation elements in the substrate integrated waveguide (SIW), low profile and compact size structure are achieved. The proposed DLP and DCP shared-aperture antenna is fabricated by adopting a multilayer PCB technology. Measured results imply the operating bandwidths of 21.6–22.6 GHz and 20.7–22.6 GHz for horizontal polarization (HP) and vertical polarization (VP). Moreover, wide 3-dB axial ratio (AR) bandwidths of the DCP element are achieved, with the peak gain of 6.5 dBi and 7.4 dBi. The antenna with features of low frequency ratio shared-aperture, high polarization diversity and low cost is suited for the millimeter-wave satellite communication system.

Normalized Ratcheting Diagram Under Sinusoidal Vibration Waves

Abstract Ratcheting is a progressive incremental inelastic deformation or strain which can occur in a component that is subjected to variations of mechanical stress, thermal stress, or both. This study concentrated on the ratcheting occurrence of the piping model under the combined effect of constant external force and dynamic cyclic vibrations. Bent solid bars represented piping models, and sinusoidal acceleration waves were loaded. Characteristics of seismic loads between load-controlled and displacement-controlled properties were studied from the viewpoint of the frequency ratio of the forcing frequency to the natural frequency of the piping model. Besides, the ratcheting occurrence conditions of the beam and the piping model were compared in one normalized diagram to display the general mechanism of ratcheting with the consideration of the effect from the difference of shape and material. Results show that ratcheting occurs easily with a lower frequency ratio in both beam and piping models. In addition, it is meaningful to use beam models to understand the ratcheting mechanism of piping models. Describing the occurrence of ratcheting using the normalized ratcheting diagram for different components is feasible.

Effect of Flexibly Attached Secondary Systems on Dynamic Behavior of Light Structures

This paper investigates the effect of flexibly attached secondary systems (FSS) on the dynamic behavior of primary structures (PS) under harmonic and seismic ground excitations. An FSS affects the main structure during ground excitation differently than a secondary system that is rigidly attached to it. Small displacements in the FSS are used to derive the equations of motion that define the behavior of the PS and FSS. The analytical formulation presented is validated by a finite element (FE) study conducted in SAP2000. The influence of mass ratio, tuning frequency ratio, and excitation frequency ratio on the dynamic behavior of the PS is investigated. The results show that the combined system (PS+FSS) behaves as a modified single degree of freedom (SDOF) structure at higher tuning frequency ratios. The dynamic response of the structure is independent of the mass ratio at low tuning frequency ratio of FSS. Under seismic excitations, the flexible structure’s response reduces considerably as the mass ratio increases, compared to a stiff structure at a higher tuning frequency ratio. When the tuning frequency ratio is equal to one, smaller mass ratios of FSS increase the seismic performance of the stiff structure. A design methodology is proposed to measure the spectral acceleration of the primary structure by incorporating the effect of FSS in the design response spectrum. An analysis of the tuning frequency ratio and mass ratio on the modified design spectrum is also presented. Finally, the proposed design methodology is validated with an existing study.

The differences between daytime and nighttime heart rate variability may usefully predict the apnea-hypopnea index in patients with obstructive sleep apnea.

The association between daytime/nighttime heart rate variability (HRV) and the apnea-hypopnea index (AHI) remains unclear. We sought a relationship between AHI and the daytime-to-nighttime HRV ratio as measured by 24-hour Holter monitoring in patients with obstructive sleep apnea. We prospectively enrolled 66 patients who visited our sleep clinic complaining of habitual snoring or sleep apnea. All underwent 24-hour Holter monitoring (to measure HRV) combined with full-night polysomnography. Sixty-two met our enrollment criteria. We evaluated the associations between HRV frequency domains and the polysomnography indices. We also considered medical histories and anthropometric data. The nighttime very-low-frequency (VLF), low-frequency (LF), and high-frequency HRVs were significantly higher than the daytime values. On correlation analysis, the day/night VLF (r = .550, P < .001), LF (r = .556, P < .001), and high-frequency (r = .303, P = .017) HRVs were significantly related to the AHI. Of the day/night HRV ratios, the VLF (P for trend = .003) and LF (P for trend = .013) ratios decreased significantly by obstructive sleep apnea severity. Multivariable analysis showed that the day/night VLF (β = 16.387, P < .001) and day/night LF (β = 25.248, P < .001) were independently (and significantly) associated with the AHI. Twenty-four-hour Holter monitoring may usefully predict AHI. The day/night VLF and day/night LF ratios tended to decrease by obstructive sleep apnea severity and were independently associated with the AHI. Nam E-C, Chun KJ, Won JY, Kim J-W, Lee WH. The differences between daytime and nighttime heart rate variability may usefully predict the apnea-hypopnea index in patients with obstructive sleep apnea. J Clin Sleep Med. 2022;18(6):1557-1563.

Short-term Heart Rate Variability to Evaluate Cardiovascular Autonomic Neuropathy in Newly Diagnosed Type 2 Diabetes Mellitus Patients: A Cross-sectional Study

Introduction: Cardiovascular Autonomic Neuropathy (CAN) may be seen in patients of Type 2 Diabetes Mellitus (T2DM). In many previous studies it was seen that there is reduced heart rate variability in DM patients. Reduced heart rate variability is earliest indicator for the CAN. In different earlier studies, it was found that results of Short-term Heart Rate Variability (HRV) analysis of five minutes is comparable to standard 24 hours HRV analysis. In DM patients CAN is mostly found to be associated with a longer duration of disease, but according to some studies CAN may be present in newly diagnosed diabetes patients also, but the percentage is lower. Aim: To assess the short-term HRV profile as cardiovascular risks among newly diagnosed T2DM patients and to find the correlation of HRV parameters with duration of disease and biochemical parameters; Fasting Plasma Glucose (FPG) and Postprandial Plasma Glucose (PPPG) for early detection and management of CAN. Materials and Methods: The present study was a cross-sectional study conducted in the Department of Physiology in collaboration with the Department of Endocrinology at R.G. Kar Medical College and Hospital, Kolkata, West Bengal, India, from September 2020 to August 2021 on 56 newly diagnosed T2DM (age group 30 to 64 years). Study subjects were grouped according to the Standard deviation of NN intervals (SDNN) (millisecond) value as cardiovascular risk factor. Group 1 was the low risk group, group 2 was the moderate risk group, group 3 was the high-risk group. HRV testing was done with Physiograph Polyrite-D instrument with bio-amplifiers, 4 channels and accessories (RMS latest software-Version 3.0.16) in Autonomic Function Research Laboratory to measure HRV parameters. After collecting data, analysis was done using Statistical Package for Social Sciences (IBM, SPSS) version 23.0 Unpaired student’s t-test, Chi-square test, Analysis of Variance (ANOVA) test, Pearson correlation test were performed and statistical significance of different parameters were evaluated. It was considered statistically significant when p-value &lt;0.05. Results: By assessing HRV parameters as cardiovascular risk factors among newly diagnosed T2DM patients the present study showed there was significantly (p-value=0.0065) high LF/HF ratio in males (1.70±1.19) than in females (0.99±0.69). The SDNN value was significantly highest in low cardiovascular risk group (137.29±25.49 ms) and lowest in high cardiovascular risk group (26.07±12.03 ms) (p-value=0.00001). Low Frequency and High Frequency Ratio (LF:HF ratio) was significantly more in age group of 51-60 years. Among all the patients, 34 (61%) patients had increased parasympathetic activity and 22 (39%) subjects had increased sympathetic activity. Female patients showed significantly more increased parasympathetic 24 (75%) activity than males 10 (41.7%). There was a significant association between SDNN values with the duration of disease (p-value=0.004). Conclusion: The present study showed that cardiac autonomic neuropathy is present even at the time of diagnosis of newly diagnosed T2DM as there was sympathovagal imbalance. Female patients have more parasympathetic drive than males which indicates that females are more cardioprotective.

Markers of Cardiac Autonomic Function During Consecutive Day Peak Exercise Tests in People With Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) have been shown to exhibit altered ventilatory characteristics on the second of two progressive maximal cardiopulmonary exercise tests (CPET) performed on consecutive days. However, maximal exercise can exacerbate symptoms for ME/CFS patients and cause significant post-exertional malaise. Assessment of heart rate (HR) parameters known to track post-exertional fatigue may represent more effective physiological markers of the condition and could potentially negate the need for maximal exercise testing. Sixteen ME/CFS patients and 10 healthy controls underwent a sub-maximal warm-up followed by CPET on two consecutive days. Ventilation, ratings of perceived exertion, work rate (WR) and HR parameters were assessed throughout on both days. During sub-maximal warm-up, a time effect was identified for the ratio of low frequency to high frequency power of HR variability (p=0.02) during sub-maximal warm-up, and for HR at ventilatory threshold (p=0.03), with both being higher on Day Two of testing. A significant group (p<0.01) effect was identified for a lower post-exercise HR recovery (HRR) in ME/CFS patients. Receiver operator characteristic curve analysis of HRR revealed an area under the curve of 74.8% (p=0.02) on Day One of testing, with a HRR of 34.5bpm maximising sensitivity (63%) and specificity (40%) suggesting while HRR values are altered in ME/CFS patients, low sensitivity and specificity limit its potential usefulness as a biomarker of the condition.

Effect of Transcranial Direct Current Stimulation associated with aerobic exercise on the autonomic modulation of hemiparetic individuals due to stroke: a study protocol for a double-blind randomized controlled trial

Background:Individuals after a stroke have an imbalance in the autonomic nervous system, which increases the risk of death or recurrent episodes of stroke. Transcranial Direct Current Stimulation (tDCS) combined with aerobic exercise has shown an effect on the modulation of this system.Objective:The Heart Rate Variability (HRV) and the distance traveled on the exercise bike will be assessed to verify the additional impact of tDCS combined with aerobic exercise on individuals with chronic stroke sequelae.Methods:The 34 adult individuals with diagnoses of chronic stroke will be randomized into two aerobic exercise intervention groups: G1 (with active tDCS) and G2 (with sham tDCS), three times a week, for 12 weeks.Procedures:tDCS will be implemented during the aerobic exercise with the anodal electrode positioned over the lateral dorsal prefrontal left cortex, and the cathodal electrode over the contralateral supraorbital region, with 2mA, for 20 minutes. Assessments will be carried out pre, immediately after the intervention, and on the 12th, 24th, 36th interventions, and 30 days later.The HRV data that are pulse interval (PI), square root of the mean of the squares of the differences between adjacent normal RR intervals (rMSSD), absolute high frequency (HF), absolute low frequency (LF), high and low frequency ratio (LF / HF) will be collected using a cardio frequency meter. The analysis of the distance traveled on the exercise bike before and after interventions will be analyzed in meters.Discussion:The autonomic control via brain networks after a stroke can be altered and can promote an increase in sympathetic tone, and a higher risk of sudden death or relapse of stroke. It is crucial to demonstrate the effectiveness of available treatments to improve the autonomic function.Trial registration:The study is registered as aBRAZILIAN CLINICAL TEST RECORD(ReBEC): U1111-1222-4588 on the 2018/10/16

Integrated therapy for post-COVID complications

People who contract COVID-19, including those with mild infections, suffer from post-COVID complications for months after they recover. These complications include chest pain, breathlessness, pulmonary fibrosis, vision problems, joint pain, loss of smell sensation, fatigue, body pain, headache, mood changes, and memory loss. The present case study is aimed at devising an integrated therapy protocol to assist in regaining overall health during post-COVID-19 recovery phase. A 56-year-old male was enrolled in post-COVID Yoga relaxation program for 13 days with complaints of fatty liver, lung fibrosis, and shortness of breath. During COVID-19, he was on ventilator support and recovered after 15 days of intensive care unit care. He was having generalized weakness and needed walking assistance upon admission. The patient was assessed for Heart Rate Variability (HRV) and pulmonary function at the baseline and after the completion of 13 days of Yoga and Ayurveda therapy. The patient showed significant improvement in forced vital capacity, slow vital capacity, and maximal voluntary ventilation after 13 days of integrated therapy. Further, a significant increase in time domain markers of HRV and a significant reduction in Low Frequency (LF) and ratio of LF to High Frequency (LF/HF) with the simultaneous increase in HF was observed. This implies an autonomic balance shift from the sympathetic to the parasympathetic system. Integrative therapy of Yoga and Ayurveda was found to be effective in mitigating the post-COVID-19 complications in this patient. The patient showed improvement in HRV and pulmonary function after integrative therapy for 13 days. Thus, Yoga and Ayurveda therapy proved to be promising and efficacious treatments in the present case study.

Effects of Mentha Piperita Essential Oil Uptake or Inhalation on Heart Rate Variability and Cardiopulmonary Regulation during Exercise

This study compares the effects of the uptake or inhalation of 50uL Mentha piperita (MP) essential oil for 10 days on heart rate variability (HRV) and cardiopulmonary regulation during various exercise intensities. Forty-eight healthy male subjects were randomly assigned to MP uptake (MPU; n=16), MP inhalation (MPI; n=16), and control group (C; n=16). All participants were measured resting HRV, respiratory, cardiovascular, and metabolic parameters during aerobic, anaero- bic, and graded exercise tests (GXT) before and after treatment. There were significant increases in the low-frequency area (LFa; 1.8±0.1 vs 2.2±0.2 ms²), the ratio of low frequency to respiration frequency area (LFa/RFa; 0.9±0.1 vs 1.3±0.1) at resting and carbon dioxide production (VCO 2 ; 41.2±4.0 vs 49.2±6.8 mL/min -1 /kg -1 ), ventilation per minute (V E ; 80.2±4.3 vs 97.5±5.5 L/min -1 ), and respiratory rate (RR; 38.2±1.9 to 44.3±2.1 breath/min -1 ) in an anaerobic test following MPU inter- vention. In GXT, maximal carbon dioxide production (VCO 2max; 51.9±3.5 to 59.1±6.4 mL/min -1 /kg -1 ), maximal ventilation per minute (V Emax ; 126.4±6.5 to 138.4±5.4 L/min -1 ) and maximal respiratory rate (RR max ; 52.7±3.6 to 60.1±2.3 breath/min -1 ) significantly increased in MPU. The correlations of ΔLFa with ΔVCO 2max , ΔV Emax , and ΔRR max in the MPU group were signifi- cant. Continuous uptake or inhalation of 50uL MP oil for 10 days does not improve aerobic capacity and maximal exercise performance, but 10 days’ uptake of MP essential oil increased sympathetic activity at rest and may relate to respiratory regulation under high-intensity exercise.

Low‐profile dual‐band dual circularly polarized patch antenna with small frequency ratio

A dual-band dual circularly polarized (CP) patch antenna is proposed with low profile and small frequency ratio in this letter, which consists of a square patch, coupling lines, and a dual-feed network with dispersive delay line. Noticing that this antenna is fabricated on a single-layer substrate, thus acquiring low-profile performance. As for the coupling scheme, the bandwidth of impedance matching is increased to achieve dual-band radiation performance. On the premise that two orthogonal signals, which transmit in two paths of the dual-feed network, provide equal magnitude, the circular polarization can be controlled by the corresponding phase difference. Benefited from the dispersive delay line, the requirements of quadrature phases are met to present left−/right-handed circularly polarizations in two operating frequencies. Meanwhile, small frequency ratio can be easily achieved. To demonstrate the proposed design, the single-layer antenna with a profile of 0.006λ0 is designed, fabricated and measured. The phase difference of two orthogonal signals is adjusted to −90° at the lower operating frequency 1.9 GHz to realize right-handed CP characteristic, while 90° phase difference in two paths is achieved at the higher one 2.4 GHz to provide left-handed CP characteristic. Measured results are found in reasonably a good agreement with the simulated ones.

The Value of Heart Rhythm Complexity in Identifying High-Risk Pulmonary Hypertension Patients.

Pulmonary hypertension (PH) is a fatal disease—even with state-of-the-art medical treatment. Non-invasive clinical tools for risk stratification are still lacking. The aim of this study was to investigate the clinical utility of heart rhythm complexity in risk stratification for PH patients. We prospectively enrolled 54 PH patients, including 20 high-risk patients (group A; defined as WHO functional class IV or class III with severely compromised hemodynamics), and 34 low-risk patients (group B). Both linear and non-linear heart rate variability (HRV) variables, including detrended fluctuation analysis (DFA) and multiscale entropy (MSE), were analyzed. In linear and non-linear HRV analysis, low frequency and high frequency ratio, DFAα1, MSE slope 5, scale 5, and area 6–20 were significantly lower in group A. Among all HRV variables, MSE scale 5 (AUC: 0.758) had the best predictive power to discriminate the two groups. In multivariable analysis, MSE scale 5 (p = 0.010) was the only significantly predictor of severe PH in all HRV variables. In conclusion, the patients with severe PH had worse heart rhythm complexity. MSE parameters, especially scale 5, can help to identify high-risk PH patients.

EFFECT OF PHYSICAL ACTIVITIES ON HEART RATE VARIABILITY AND SKIN CONDUCTANCE

The sympathetic and parasympathetic function of the Autonomic Nervous System (ANS) is the primary cause of the variations in Heart Rate and Skin Conductance (SC) during different physical activities. This paper aims to analyze the effect of different physical activities i.e. (a) Supine (b) Standing and (c) Warm-up, on Heart Rate Variability (HRV) and SC. The standard dataset of 18 subjects has been used to analyze the effect of physical activities on the HRV and SC. In the used dataset, the subjects are in supine, standing, and warm-up positions. The linear methods (time domain &amp; frequency domain) of HRV are implemented on the standard dataset for analyzing the effect of physical activities. It has been observed with the analysis of the HRV that the mean value of time domain methods i.e. the NN interval’s standard deviation (SDNN), the successive RR interval’s root mean square (RMSSD), RR intervals with more than 50 ms differences in between them (NN50), percentage of successive RR intervals that have the difference of more than 50 ms (pNN50) are decreased and the value of Heart rate (HR) increased when the activity has been changed from supine to standing and standing to the warm-up positions. The value of frequency domain methods, such as low frequency (LF) and the ratio of low and high frequency (LF/HF) increased, while the value of HF decreases as activity changes from supine to standing and from supine to warm-up position. Further, the increment is also observed in the value of SC when activity is switched from supine to standing and from standing to the warm-up position. It is concluded from the results that there is a significant decrement that is observed in the value of HRV, while the increment is observed in the value of SC and HR. Decrement of HRV reflects that the sympathetic activity is increased as activity changed from supine to standing and further from standing to warm-up positions.

The Physio-Psychological Effect of Forest Therapy Programs on Juvenile Probationers

The study aimed to investigate the psychological and physiological effects of forest therapy programs on adolescents under probation. Fifty probationary teenagers from the Ministry of Gyeonggi Justice Compliance Support Center participated in the study. The study explored the effectiveness of a nonrandomized control group pretest–posttest design forest therapy program. The forest therapy program was conducted for two days and one night for the experimental groups (N = 33), who participated in the forest therapy program, and the control group (N = 17), who received two days of attendance center orders program in the lecture room of the Ministry of Gyeonggi Justice Compliance Support Center. As a result, adolescents under probation who participated in forest therapy programs had a beneficial effect on psychological well-being (K-WBMMS) and HRV’s HF (high frequency) and LF/HF (A ratio of Low Frequency to High Frequency) compared to those who received the general attendance center orders program. These results support that forest therapy programs play a positive role in the psychological and physiological effects of probationary adolescents and can affect the diversity of rehabilitation programs for probationary adolescents.

89 Learning ability and physiological stress response of horses (Equus caballus) undergoing discrimination and reversal learning tasks using a touch screen

The objective of this study was to evaluate the cognitive abilities and physiological stress responses of horses ( Equus caballus ) undergoing discrimination and reversal learning tasks using a touch screen powered by a computer. Utilizing such technology to present stimuli and collect data points provided standardization across all test subjects, and removed human error and bias from the experimentation. The study population consisted of 9 horses and ponies, all managed similarly at the same facility. The horses, 5 mares and 4 geldings, were aged 10–23 years (mean 14.8, ± 3.03). These 9 subjects were tested on discrimination learning based on their ability to select a pre-determined 2-dimensional shape (black circle or triangle) and their performance measured as a percentage of correct responses within a given session. Latency to touch the screen was also recorded, in seconds. Once this task was acquired, as determined by completing 2 consecutive sessions at ≥ 80% performance, the horses were then tested on reversal learning by switching the previously-rewarded shape to the unrewarded one, and the previously-unrewarded shape to the rewarded one. Before any experimentation began, horses were habituated to the experimental environment and shaped to touch the screen with their muzzles. Positive reward in the form of food was the only reinforcement method used throughout the study. The following physiological stress variables were recorded during all sessions by Polar H10 Heart Rate Sensors: standard deviation of NN intervals (SDNN), root mean square of successive rr-interval differences (RMSSD), and the ratio of low frequency to high frequency (LF/HF). Statistical analysis was performed using Spearman rank correlation coefficients to assess the potential relationships between performance, latency, and any of the stress variables. Results showed that performance and latency were positively correlated in both discrimination and reversal learning ( P < 0.001, Spearman's rho = 0.358, α = 0.05 and P < 0.001, and Spearman's rho = 0.512, α = 0.05, respectively). No significant correlation was found between either performance or latency and SDNN, RMSSD, or LF/HF. These results suggest that making comparatively slow, deliberate choices were linked to a higher performance.

Stochastic analysis of a galloping-random wind energy harvesting performance on a buoy platform

A new concept of a galloping-random wind energy harvester, which is a galloping-based piezoelectric harvester mounted on a buoy platform is proposed. The galloping-random wind energy harvester can concurrently harvest galloping energy due to the aero-instability and stochastic vibration energy due to the ocean wave. The harvester performance is comprehensively investigated through wind tunnel experiments and theoretical investigation. The mathematical model of the system is formulated, and its aerodynamic galloping is then validated with wind tunnel experimental measurements. Based on the verified mathematical model of the galloping-random wind energy harvester, the stochastic average method is applied to analytically obtain the probability density functions of the system’s stochastic responses and the average harvested power. The fidelity of the analytical solution is also verified by the numerical integration using the Euler-Maruyama algorithm. The results show that a unique crater phenomenon is discovered in the joint PDF of the responses, owing to the concurrent galloping and stochastic vibrations. In this case, the energy harvester exhibits a periodic galloping response with a fluctuating amplitude. The annulus range is wider when the galloping response is dominant and becomes stronger. In addition, this study investigates the average power output in terms of the stochastic excitation intensity, structural natural frequency, aerodynamic mass ratio, and normalized electrical term, to provide the useful design guidelines. The results show that the strong stochastic excitation intensity is beneficial to broadband energy harvesting and especially provides a high advantage for the low wind speed. The low structural natural frequency and large aerodynamic mass ratio can improve the performance. The parametric study also uncovers the optimal electrical term that can significantly improve the broadband average power output.

Effect of Transcranial Direct Current Stimulation associated with aerobic exercise on the autonomic modulation of hemiparetic individuals due to stroke: a study protocol for a double-blind randomized controlled trial

Background: Individuals after a stroke have an imbalance in the autonomic nervous system, which increases the risk of death or recurrent episodes of stroke. Transcranial Direct Current Stimulation (tDCS) combined with aerobic exercise has shown an effect on the modulation of this system. Objective: The Heart Rate Variability (HRV) and the distance traveled on the exercise bike will be assessed to verify the additional impact of tDCS combined with aerobic exercise on individuals with chronic stroke sequelae. Methods: The 34 adult individuals with diagnoses of chronic stroke will be randomized into two aerobic exercise intervention groups: G1 (with active tDCS) and G2 (with sham tDCS), three times a week, for 12 weeks. Procedures: tDCS will be implemented during the aerobic exercise with the anodal electrode positioned over the lateral dorsal prefrontal left cortex, and the cathodal electrode over the contralateral supraorbital region, with 2mA, for 20 minutes. Assessments will be carried out pre, immediately after the intervention, and on the 12th, 24th, 36th interventions, and 30 days later. The HRV data that are pulse interval (PI), square root of the mean of the squares of the differences between adjacent normal RR intervals (rMSSD), absolute high frequency (HF), absolute low frequency (LF), high and low frequency ratio (LF / HF) will be collected using a cardio frequency meter. The analysis of the distance traveled on the exercise bike before and after interventions will be analyzed in meters. Discussion: The autonomic control via brain networks after a stroke can be altered and can promote an increase in sympathetic tone, and a higher risk of sudden death or relapse of stroke. It is crucial to demonstrate the effectiveness of available treatments to improve the autonomic function. Trial registration: The study is registered as a BRAZILIAN CLINICAL TEST RECORD (ReBEC): U1111-1222-4588 on the 2018/10/16

Specific oral and maxillofacial identifiers in panoramic radiographs used for human identification

Radiographically assisted dental identification is an important means for individual identification. Specific identifiers help to quickly filter some of the possible corresponding AM and PM images at the beginning. The study seeks specific oral and maxillofacialidentifiers in panoramic radiographs. A total of 920 panoramic radiographs from 460 live patients were used. The most recent radiograph served as the surrogate post-mortem (PM) record of an unidentified person, and the earliest radiograph served as the ante-mortem (AM) record of the same person. We evaluated the following four groups of identifiers of the images: (1) dental morphology, tooth number, and position; (2) dental treatment and pathology; (3) morphological identifiers of the jaw; and (4) pathological identifiers of the jaw. The ratio of each identifier being identified simultaneously in the AM and PM databases was determined. Specific identifiers were defined as those that appeared at low frequency (ratio: 0%-0.250%). A total of 18 specific oral and maxillofacial identifiers were determined. The specific identifiers were a retained deciduous tooth (0.011%), S-shaped deflection of a tooth root (0.012%), distal deflection of tooth root (0.017%), inverted impaction (0.018%), malposition (0.038%), supernumerary teeth (0.061%), mesial deflection of tooth root (0.092%), microdontia (0.136%), buccal/lingual impaction (0.188%), cementoma (0.002%), hypercementosis (0.002%), continuous crown (0.004%), pulp calcification (0.023%), attrition (0.030%), residual root (0.106%), root resorption (0.137%), implant (0.156%), and osteomyelitis (0.002%). Identifiers of the teeth and jaw can be used for human identification, and dental identifiers are more specific than identifiers of jaw.

The Influence of Emotionally Linked Odors on Autonomic Nerve Activities

The limbic system, supporting emotions, behavioral motivation, and memory, in the brain receives coming odor before the sensory cortex. Therefore, certain odor can affect autonomic nerve system and physiological parameters due to smell-induced activity in the limbic system. The purpose of this study focused was to investigate the influence of odor, taking the level of arousal and valence into account, on autonomic nerve activities and physiological parameters. Eight healthy young males (20.6 ± 0.5 yr), who gave a response of high arousal (6.8 ± 0.5) and negative valence (1.5 ± 0.8) to the odor of vinegar (VNG), and an opposite response (arousal 2.3 ± 0.8, valence 6.6 ± 0.4) to the odor of orange (ORG), were selected as subjects. Heart rate and its variability (HRV), and blood pressure (BP) were evaluated for the subjects who were quietly seated, wore a plastic mask with a vapored odor-injection pipe, and breathed naturally the two aromas (VNG, and ORG). A no aroma condition was also included in the test as a control. Repeated measures ANOVA with a Turkey post-hoc test revealed a significant odor effect in the variables of HRV, and BP. VNG led to a higher ratio of low frequency /high frequency (LF/HF), and lower HF compared to the control (p < 0.05, p < 0.05, respectively). VNG also had significantly higher diastolic and mean BP than ORG (p < 0.05, p < 0.05, respectively). ORG, on the other hand, failed to show any significant odor effect on HRV and BP variables. LF/HF can be a sympathetic nerve activity indicator while HF is known as a para-sympathetic nerve activity indicator. Our results of breathing VNG thus suggests that odors causing negative valence and high arousal can facilitate sympathetic nerve activity, and/or withdraw para-sympathetic nerve activity. A higher BP with VNG compared to ORG can also be attributed to the effect of these autonomic nerve activities. Consider all the various factors together, it can be concluded that some emotionally linked odors were strong enough to modulate autonomic nerve activities as well as the level of BP in resting individuals.