Differences In Peak Time Research Articles

Accurate simulation of extreme rainfall–flood events via an improved distributed hydrological model

Recently, the high incidence of extreme rainfall and flood events worldwide has severely harmed regional economies and societies. Therefore, flood simulations and forecasts, which can provide key technical support for regional flood control and disaster reduction, are urgently needed. The Liuxihe model, as a fully distributed, physically based hydrological model, was improved in this study to simulate extreme rainfall flood events in the Beijiang River Basin. This basin is a famous rainstorm centre in Guangxi Province, China. In this work, the Liuxihe model is improved in two aspects: first, its structure and runoff generation and confluence algorithm are improved, and second, the parameter calibration method is optimised. These two adjustments improve the flood simulation performance of the model and reduce the uncertainty of the simulation results. The results revealed that the flood simulated by the improved Liuxihe model was strongly consistent with the measured values, and the index values of the Nash coefficient, correlation coefficient, process relative error, and flood peak flow error performed very well in the scheme evaluation; in particular, the mean process relative error, flood peak error, and peak time difference decreased by 62%, 63%, and 80%, respectively, after model improvement. The error indicators of the simulation were within the allowable error range from the Standard for Hydrological Information and Hydrological Forecasting (GB/T-22482–2008), which meets the accuracy requirements of flood forecasting in the local hydrological department and can be used as a practical operational plan for flood forecasting. These satisfactory flood simulation results showed that the model and algorithm were improved; thus, the improved Liuxihe model can provide important theoretical guidance for regional flood forecasting and flood disaster mitigation.

Flash Flood Simulation for Hilly Reservoirs Considering Upstream Reservoirs—A Case Study of Moushan Reservoir

With the advancement of society and the impact of various factors such as climate change, surface conditions, and human activities, there has been a significant increase in the frequency of extreme rainfall events, leading to substantial losses from flood disasters. The presence of numerous small and medium-sized water conservancy projects in the basin plays a crucial role in influencing runoff production and rainwater confluence. However, due to the lack of extensive historical hydrological data for simulation purposes, it is challenging to accurately predict floods in the basin. Therefore, there is a growing emphasis on flood simulation and forecasting that takes into account the influence of upstream water projects. Moushan Reservoir basin is located in a hilly area of an arid and semi-arid region in the north of China. Flooding has the characteristics of sudden strong, short confluence time, steep rise, and steep fall, especially floods caused by extreme weather events, which have a high frequency and a wide range of hazards, and has become one of the most threatening natural disasters to human life and property safety. There are many small and medium-sized reservoirs in this basin, which have a significant influence on the accuracy of flood prediction. Therefore, taking Moushan Reservoir as an example, this paper puts forward a flash flood simulation method for reservoirs in hilly areas, considering upstream reservoirs, which can better solve the problem of flood simulation accuracy. Using the virtual aggregation method, the 3 medium-sized reservoirs and 93 small upstream reservoirs are summarized into 7 aggregated reservoirs. Then, we construct the hydrological model combining two method sets with different runoff generation and confluence mechanisms. Finally, after model calibration and verification, the results of different methods are analyzed in terms of peak discharge error, runoff depth error, difference in peak time, and certainty coefficient. The results indicate that the flooding processes simulated by the proposed model are in line with the observed ones. The errors of flood peak and runoff depth are in the ranges of 2.3% to 15% and 0.1% to 19.6%, respectively, meeting the requirements of Class B accuracy of the “Water Forecast Code”. Method set 1 demonstrates a better simulation of floods with an average flood peak error of 5.63%. All these findings illustrate that the developed model, utilizing aggregate reservoirs and dynamic parameters to reflect regulation and storage functions, can effectively capture the impact of small water conservancy projects on confluence. This approach addresses challenges in simulating floods caused by small and medium-sized reservoirs, facilitating basin-wide flood prediction.

Changes in Fingertip Cold-Induced Vasodilatation (Hunting Reaction) on Acute Exposure to Altitude.

Fossati, Alexandre, and Aleid C. J. Ruijs. Changes in fingertip cold-induced vasodilatation (hunting reaction) on acute exposure to altitude. High Alt Med Biol. 25:212-217, 2024. Objective: Cold-induced vasodilation (CIVD) of the extremities is an interesting part of human physiology. Although the physiology of the CIVD reaction remains unknown, there are indications that hypoxia influences our CIVD reaction. The objective of this study is to measure the influence of acute hypoxia on the CIVD reaction of the fingertips. Methods: The CIVD reaction was measured using immersion of one hand in a water bath of 0°C in 12 healthy volunteers at low (1,235 m) and high (3,800 m) altitude during 35 minutes. High altitude was reached by a 20-minute cable car ride. Testing was performed indoors (room temperature, 22-25°C) at both altitudes. Data analysis was performed measuring the parameters of the CIVD reaction. Differences were found using the paired Student's t-test. Results: There was no significant difference in baseline finger temperature, onset time, peak time, and frequency of the CIVD reaction. However, at high altitude, maximum temperature and amplitude were significantly higher, slope was steeper, and minimum temperature was lower. Conclusion: We did not find evidence for a diminished CIVD reaction at high altitude due to hypoxia.

ERG Responses in Albinism, Idiopathic Infantile Nystagmus, and Controls.

Our primary aim was to compare adult full-field ERG (ffERG) responses in albinism, idiopathic infantile nystagmus (IIN), and controls. A secondary aim was to investigate the effect of within-subject changes in nystagmus eye movements on ffERG responses. Dilated Ganzfeld flash ffERG responses were recorded using DTL electrodes under conditions of dark (standard and dim flash) and light adaptation in 68 participants with albinism, 43 with IIN, and 24 controls. For the primary aim, the effect of group and age on ffERG responses was investigated. For the secondary aim, null region characteristics were determined using eye movements recorded prior to ffERG recordings. ffERG responses were recorded near and away from the null regions of 18 participants also measuring the success rate of recordings. For the primary aim, age-adjusted photopic a- and b-wave amplitudes were consistently smaller in IIN compared with controls (P < 0.0001), with responses in both groups decreasing with age. In contrast, photopic a-wave amplitudes increased with age in albinism (P = 0.0035). For the secondary aim, more intense nystagmus significantly reduced the success rate of measurable responses. Within-subject changes in nystagmus intensity generated small, borderline significant differences in photopic b-wave peak times and a-and b-wave amplitudes under scotopic conditions with standard flash. Age-adjusted photopic ffERG responses are significantly reduced in IIN adding to the growing body of evidence of retinal abnormalities in IIN. Differences between photopic responses in albinism and controls depend on age. Success at obtaining ffERG responses could be improved by recording responses at the null region.

Validating IMERG data for diurnal rainfall analysis across the Indonesian maritime continent using gauge observations

The availability of surface rainfall data with high spatial-temporal resolution is needed to understand the diurnal rainfall characteristics in the Indonesian Maritime Continent (IMC) to improve the accuracy of weather and climate models in this region. This study validates the accuracy of the Final Run product of IMERG data version 06B (V06B) and version 07A (V07A), which have a resolution of 0.1°–30 min for diurnal rainfall analysis over IMC. Validation was conducted for precipitation amount (PA), precipitation frequency (PF), and precipitation intensity (PI), by recording 302 automatic rain gauges (RG) every 10 min from January 2014 to September 2021. IMERG V06B and V07A perform well in observing diurnal PA and PF but struggle in observing diurnal PI compared to RG observations. This has been determined by the correlation coefficient (CC) values of IMERG V06B (V07) data, which are 0.76 (0.72) for PA, 0.77 (0.76) for PF, and 0.21 (0.13) for PI. The IMERG data align to an extent with RG observations for the PA value, having a small relative bias (RB). The results also display a systematic PF and PI values error. The high false alarm ratio (FAR) of IMERG data suggests rain detection errors, leading to overestimated PF values. Additionally, the underestimation of PI values is due to the limitation of IMERG data in observing extreme and small-scale rain events. About 86.10% (78.14%) and 81.45% (81.78) of IMERG V06B (IMERG V07A) data show a peak time difference of <3h for PA and PF when compared with RG observations. Overall, IMERG V06B performs better than V07, possibly due to inaccurate orbits of GPROF data, removal of SAPHIR satellite observations, and inter-calibration issues with CORRA and GPCP data. Continuous monitoring and data improvements are necessary to improve the accuracy and reliability of IMERG data in detecting diurnal rainfall patterns in the IMC region.

Potential Dam Breach Flood Assessment with the 2D Diffusion and Full Dynamic Wave Equations Using a Hydrologic Engineering Center-River Analysis System

Dam breaches have catastrophic consequences, causing severe property damage, life loss, and environmental impact. The potential dam breach downstream flooding of the Kulekhani reservoir, Nepal, was studied using a 2D Diffusion Wave Equation (DWE) and Full Dynamic Wave Equation (FDWE) through an open-source solver, Hydrologic Engineering Center-River Analysis System (HEC-RAS). The suitable dam breach model was identified based on the dam geometry and sixteen historical dam failure cases. The simulated downstream peak was tested with an empirical relation, considering reservoir volume and duration of failure. Model comparisons through the flood plain mapping of water depth, flow velocity, flood intensity as per guidelines of the American Society of Civil Engineers (ASCE), and arrival time were carried out for flood hazard assessment. FDWE was able to capture the physical flow phenomena in the river bend resulting in higher flow velocity at the outer bend, lower velocity at the inner bend, and formation of eddies due to the application of the turbulence model, considering possible momentum losses, whereas DWE was unable to capture these effects due to a simplified momentum equation. The total area of flood extension was found to be increased by 30% using FDWE than the DWE due to higher water surface elevation. Most of the towns along the Kulekhani River were classified as “Very High” intensity flood regions according to ASCE, due to the V-shape valley. The peak time difference at the Bagmati River confluence was evaluated between the models. This plays an important role in decision-making for the selection of the flood model to make a safe evacuation plan. The application of FDWE was found to be suitable for the rapidly varying unsteady flow in the steep meandering river.

Noninvasive characterization of peripheral sympathetic activation across sensory stimuli using a peripheral arterial stiffness index.

Introduction: The peripheral arterial stiffness index has been proposed and validated as a noninvasive measure quantifying stimulus intensity based on amplitude changes induced by sympathetic innervation of vascular tone. However, its temporal response characteristics remain unclear, thus hindering continuous and accurate monitoring of the dynamic process of sympathetic activation. This paper presents a study aimed at modeling the transient response of the index across sensory stimuli to characterize the corresponding peripheral sympathetic activation. Methods: The index was measured using a continuous arterial pressure monitor and a pulse oximeter during experiments with local pain and local cooling stimuli designed to elicit different patterns of sympathetic activation. The corresponding response of the index was modeled to clarify its transient response characteristics across stimuli. Results: The constructed transfer function accurately depicted the transient response of the index to local pain and local cooling stimuli (Fit percentage: 78.4% ± 11.00% and 79.92% ± 8.79%). Differences in dead time (1.17 ± 0.67 and 0.99 ± 0.56 s, p = 0.082), peak time (2.89 ± 0.81 and 2.64 ± 0.68 s, p = 0.006), and rise time (1.81 ± 0.50 and 1.65 ± 0.48 s, p = 0.020) revealed different response patterns of the index across stimuli. The index also accurately characterized similar vasomotor velocities at different normalized peak amplitudes (0.19 ± 0.16 and 0.16 ± 0.19 a.u., p = 0.007). Discussion: Our findings flesh out the characterization of peripheral arterial stiffness index responses to different sensory stimuli and demonstrate its validity in characterizing peripheral sympathetic activation. This study valorizes a noninvasive method to characterize peripheral sympathetic activation, with the potential to use this index to continuously and accurately track sympathetic activators.

Two-dimensional speckle tracking imaging to assess the hazards of left ventricular function and ventricular wall motion disorders in children with pre-excitation syndrome and the efficacy of radiofrequency ablation treatment.

Our study aimed at analyzing the echocardiographic multi-indicator evaluation of the risk of Wolff-Parkinson-White syndrome (WPW) on the left ventricular function and ventricular wall motion disorders, as well as the effect of radiofrequency ablation treatment. The clinical data of 55 WPW patients treated with radiofrequency (RF) ablation at the Children's Hospital of Nanjing Medical University between January 2018 and December 2022 were retrospectively analyzed and included in the observation group, while other 50 healthy children were included in the control group during the same time. We analyzed the echocardiographic indices of the patients, assessed the effects of the disease on left ventricular myocardial function and ventricular wall motion disorders, and evaluated the effects of radiofrequency ablation treatment on the myocardium of the left ventricle. The echocardiographic parameters were analyzed to assess the effect of the disease on left ventricular myocardial function and ventricular wall dyskinesia. Of the 55 patients with pre-excited syndrome, 20 had type A bypass and 35 had type B bypass. Ten patients had pre-excited dilated cardiomyopathy with significant enlargement of the left ventricular cavity, reduced left ventricular systolic function, and a significant impairment of ventricular wall motion; the other 5 patients had basal segmental septal motion incoordination. Compared to the control group, patients with left ventricular end-diastolic diameter (LVEDD) (42.9±5.0 mm vs. 39.2±3.0 mm), peak strain dispersion (PSD) (38.8±15.3 ms vs. 21.7±2.2 ms), maximum peak time difference (MPTD) (200.2±92.8 ms vs. 89.5±9.8 ms) and interventricular mechanical delay (IVMD) (36.2±13.7 ms vs. 21.2±2.1 ms) before RF ablation were increased. Left ventricular ejection fraction (LVEF) (57.1±9.1% vs. 65.9±2.6%), E/A (1.1±0.2 vs. 1.8±0.2) and global longitudinal strain (GLS) (-18.7±2.2% vs. -22.4±0.5%) decreased, with statistically significant differences (p<0.05). All 55 patients had a successful procedure, and all postoperative echocardiographic parameters were found to be improved, compared to the preoperative period. The results of the postoperative review after 3 months showed differences in E/A, PSD, MPTD, and IVMD compared to the healthy group, suggesting that left ventricular diastolic function and synchrony had not fully returned to normal. Echocardiography can better evaluate myocardial motion and function in patients with Wolff-Parkinson-White syndrome and monitor the effect and progress of disease treatment, and has high clinical application value.

Pattern visual evoked potential and foveal sensitivity in amblyopia.

Amblyopic eyes show impaired visual functions such as poor visual acuity and reduced foveal sensitivity. The purpose of this study was to determine the association between foveal threshold and visual evoked potentials (VEP) in strabismic and anisometropic amblyopia. Forty-five subjects (age range: 7-28years, 43.3% female) including 15 strabismic and 15 anisometropic amblyopes, and 15 age-similar control subjectsparticipated in this study. Each subject had pattern visual evoked potentialsand foveal threshold recorded in each eye using RetiScan (Roland Consult, Germany) and Humphrey Visual Field Analyzer II (HFA II; Carl Zeiss Meditec Inc., Dublin, CA), respectively. These outcomes were comparedamong the amblyopic eyes, their fellow eyes, and the control eyes. Compared to the amblyopic eyes (Mean ± SD: 33.4 ± 3.48dB), the foveal threshold was higher in fellow eyes (37.0 ± 2.04dB, p = 0.0002) and incontrol eyes (38.7 ± 0.96dB, p < 0.0001). Strabismic amblyopes had a lower foveal threshold than anisometropic amblyopes (31.8 ± 3.86 vs. 35.0 ± 2.17dB, p = 0.005). Relative to the P100 peak time in fellow eyes (1°checks:116.1 ± 9.00ms; 0.25°checks:118.8 ± 5.67ms), amblyopic eyes had delayed P100 peak times for both 1° (122.7 ± 11.4ms, p < 0.0001) and 0.25° (130.4 ± 11.2ms, p < 0.0001) check sizes. There were also significant differences in P100 peak time between amblyopic and control eyes (1°:122.7 ± 11.4 vs.112.4 ± 5.01ms, p = 0.15; 0.25°:130.4 ± 11.2 vs.113.9 ± 5.71ms, p < 0.0001) and between fellow and control eyes (0.25°:118.8 ± 5.67 vs.113.9 ± 5.71ms, p = 0.009). Amblyopic eyes exhibited lower N75-P100 amplitudes than fellow eyes (1°:12.6 ± 7.96 vs.15.9 ± 8.82µV, p = 0.01; 0.25°:10.6 ± 6.11 vs. 15.8 ± 10.6µV, p = 0.001) and control eyes (0.25°: p = 0.0008). Foveal threshold correlated negatively with P100 peak time (1°: r = -0.45, p = 0.002 and 0.25°: r = -0.58, p < 0.0001) and positively with N75-P100 amplitude responses (1°: r = 0.42, p = 0.004 and 0.25°: r = 0.52, p = 0.002). Amblyopic eyes showed reduced pattern VEP amplitudes and delayed peak times with significant associations with the foveal sensitivity. However, the VEP measures overlapped extensively between amblyopic and control eyes with no apparent criterion value for optimal discrimination, suggesting that foveal sensitivity might be a better discriminator of amblyopia than pattern VEP.

The MFL detection method by the gradient hall sensors array for the cracks on the top surface of the rails

Cracks on the top surface of the rails due to contact fatigue are usually narrow and variable in direction. Thus, more spatial features need to be explored when using the magnetic flux leakage detection method. In this article, we proposed a way to predict the size and direction of the cracks by the gradient hall sensors array. First, the experimental equipment was designed for leakage field signal detection. Then, the peak time differences of the leakage field signal were analyzed to predict the crack angle, and the magnetic gradient modulus was calculated to predict the crack width. Furthermore, the principal component analysis was performed to reduce the number of eigenvalues. With that, BP neural network algorithm was used to predict the length and depth of the cracks. The experimental results indicate that the method can improve the accuracy of crack prediction, and the average relative errors of the prediction for crack angle, width, length, and depth were 5.7%, 15.3%, 9.2%, and 11.2%, respectively.

Analysis of plantar impact characteristics of walking in patients with flatfoot according to basic mechanical features and continuous wavelet transform

Flatfoot is a common foot deformity, and the collapse of the arch structure affects the foot cushioning during walking. A growing number of scholars have found that the analysis of the impact force should be combined with both the magnitude and the frequency of the impact force. Therefore, the aim of this study is to investigate the plantar impact characteristics of flatfoot patients and normal foot people at different load-bearing buffer stage from the time and frequency domains. Sixteen males with flatfoot and sixteen males with normal foot were recruited to walk on the plantar pressure test system at the same step speed, and the vertical ground reaction force data were collected from the heel contact stage and the arch support stage. The differences in the frequency domain of the ground reaction force between the flatfoot and the normal foot in the two stages were analyzed according to the basic mechanical characteristics and the continuous wavelet transform. Independent sample t-test was used to compare the baseline data of subjects, and the differences in foot impact force characteristics at different stages of foot type and weight-bearing cushion phase were compared by two-factor repeated measures Analysis of Variance. 1) In terms of basic mechanical characteristics, In both groups for flatfoot patients and normal foot people, the peak ground reaction force was higher in the arch support stage compared to the heel contact stage (Pflatfoot&amp;lt;0.001, Pnormal foot&amp;lt;0.001), and the load rate of force change was smaller in this stage (Pflatfoot&amp;lt;0.001, Pnormal foot&amp;lt;0.001). However, no differences in peak ground reaction force and time of occurrence were found between flatfoot and normal foot in the two stages (p &amp;gt; 0.05), in the arch support stage, the force change load rate of patients with flatfoot was lower than that of normal foot people (p = 0.021). 2) The results of time and frequency domain characteristics showed that during the heel contact and the arch support stage, no significant differences in the maximum signal power as well as the corresponding time and the frequency of the main impact force between the normal foot and the flatfoot were found. In both flatfoot and normal foot types, compared with the foot heel contact stage, the maximum signal power in the arch support stage was higher (Pflatfoot &amp;lt; 0.001, Pnormal foot&amp;lt;0.001), and the corresponding impact frequency was smaller (Pflatfoot = 0.002, Pnormal foot = 0.004). Once the step speed was controlled, the flatfoot patients only showed a smaller impact force load rate in the arch support stage, which may be related to their lower arch rigidity. The characteristics of the impact force in different stages of walking support period were different in time and frequency domain, suggesting that there may be differences in the function of various parts of the foot.

The Characteristics of Thunderstorms and Their Lightning Activity on the Qinghai-Tibetan Plateau

This paper discusses the temporal and spatial distribution characteristics of cloud-to-ground (CG) lightning activity over the Qinghai-Tibetan Plateau (QTP) from 2009 to 2018 and their dependence on meteorological factors. It is found that (1) the number of CG flashes fluctuates, reaches a maximum in 2014, and then gradually decreases. The main active period of CG lightning is from June to September each year, after which it decreases rapidly. CG lightning is mainly distributed in the valley areas at around 4800 m above sea level at Lhasa, Nagqu, and Chamdo, and there are differences in the characteristics of CG activity in these three areas. The peak of daily CG lightning occurs at 1000 UTC, and the lowest value is at 0400 UTC. The distribution of CG lightning in all seasons has obvious differences in peak time and the proportion of positive CG (+CG) lightning, with the ratio of +CG lightning to total CG lightning flashes in spring and autumn exceeding 50%. (2) The ratio of +CG lightning to total CG lightning flashes over the QTP is influenced by a combination of thermodynamic and microphysical factors. Over the QTP, greater vertical wind shear leads to the movement of upper positive charges and promotes the occurrence of +CG lightning. Also, the higher total column liquid water content implies higher cloud water content in the warm-cloud region, and the higher cloud-base height implies a thicker warm-cloud region, which is not conducive to the occurrence of +CG lightning. (3) During high-value years (in this study, 2010, 2012, 2014, and 2016), the midlatitude (30°N–60°N) high pressure is strong and the plateau is situated at the intersection of the East Asian and South Asian monsoons and the cold air from the northwest, which strengthens the water vapor convergence and increases the frequency of thunderstorms. When the plateau is under the control of the southerly monsoon from June to September every year, its atmosphere is full of water vapor and lightning activity is accordingly high, with the proportion of +CG lightning being about 10%. Meanwhile, in the remaining months, when controlled by the westerly wind belt, the plateau’s water vapor condition is poor, the level of lightning activity weakens, and the proportion of +CG lightning gradually increases to more than 50%.

Gap in the conditioned stimulus: Differential impacts on temporal expectancy in appetitive and aversive conditions in rats

We analyzed, through a Pavlovian conditioning procedure in rats, the temporal pattern of behavior in appetitive and aversive conditions within subjects, and the difference in inferred temporal working memory functioning with the Gap paradigm. For both conditions, we paired a 60-s conditioned stimulus (CS: tone1 or tone2) with an unconditioned stimulus (US: shock or chocolate pellet) delivered 20s after CS onset. The analyses of mean response rate and individual-trial data were performed during Probe trials, consisting of CS alone, and trials in which gaps of different position or duration were inserted, to assess the effect of the temporal manipulation on behavior. The results showed: (1) An anticipatory peak time in the aversive condition but better accuracy in the appetitive condition, (2) constancy in the Weber fraction suggesting that the difference in peak time was under clock control, (3) a graded effect of gap parameters only in the aversive condition and (4) different gap effects between conditions when a gap was inserted early in the CS. These results highlight behavioral differences between aversive and appetitive conditions and suggest that the temporal working memory mechanism was not engaged in the same manner in each condition.

Electroretinography in adults with high-functioning autism spectrum disorder.

The electroretinogram (ERG) allows the investigation of retinal signaling pathways and has increasingly been applied in individuals with mental disorders in search for potential biomarkers of neurodevelopmental disorders. Preceding ERG examinations in individuals with autism spectrum disorders (ASD) showed inconsistent results, which might be due to the small number of participants, heterogeneity of the ASD population, differences in age ranges, and stimulation methods. The aim of this study was to investigate functional retinal responses in adults with ASD by means of the light-adapted (photopic) ERG. Light-adapted ERG measurements were obtained with the RETeval® system applying three different stimulation protocols. In the final analysis, the ERG parameters a-wave, b-wave, the photopic negative response (PhNR), the photopic hill parameters as well as additional amplitude ratios were compared between 32 adults with high-functioning ASD and 31 non-autistic controls. Both groups were matched with regard to sex and age. No significant functional retinal differences in amplitude or peak time of the a- or b-wave, PhNR, the photopic hill parameters or the ERG-amplitude ratios could be detected in individuals with ASD compared to non-autistic participants. The absence of electrophysiological functional retinal alterations in ASD, suggests that changes in visual perception, such as increased attention to detail or visual hypersensitivity in ASD, are not due to impairments at early levels of retinal signal processing.

Use of pulsars for ship navigation: an alternative to the sextant

AbstractA new method is proposed for determining a ship's position at sea using naturally occurring pulsar signals to provide an alternative to the sextant. Use is made of four distinct pulsar radio signals whose timing stabilities are comparable to atomic clocks and whose characteristic signatures can be used as natural radio navigation beacons. Pulse peak time difference measurements, accurate to within 10−5and 10−6s, were generated for a key reference observatory which provides long-term pulsar timing observations and for the unknown ship location. These time differences when multiplied by the velocity of light provide a distance value that is fundamental in calculating the ship's position. Resultant simulations provided a position accuracy to ≈1⋅1 km (≈0⋅6 nm) for the higher timing difference measurement. A single-pulsar-based approach, which gave a position accuracy to ≈2⋅8 km (≈1⋅5 nm), was also investigated for affordable equipment solutions and comparison with NASA space-based navigation experiments.

Characteristics of extreme precipitation and related near surface atmospheric conditions in summer over the Tibetan Plateau from GPM observations and multi-source reanalysis datasets

This study aims to investigate the characteristics of extreme precipitation and related near surface atmospheric conditions in the summer (June–August) of 2014–2019 over the Tibetan Plateau (26°N-38°N, 78°E-100°E) by using GPM satellite observations and multi-source reanalysis datasets (ERA5, ERA-Interim and CFSv2). Results show that there are notable regional differences in spatial distribution and peak time of extreme precipitation over the Tibetan Plateau. The frequency and intensity of extreme precipitation over the main body of the Tibetan Plateau are smaller than those in the south slope of the Himalayas, whereas the storm top height over the main body of the Tibetan Plateau is higher than that in the south slope. Besides, the storm top height of intense extreme precipitation can reach 17 km. The peak time of extreme precipitation over the Tibetan Plateau mostly occur in the afternoon and midnight. Further analysis reveals that near surface temperatures corresponding to extreme precipitation over the main body of the Tibetan Plateau and the south slope of the Himalayas are approximately 285–290 K and 295–300 K (11.85 °C–16.85 °C and 21.85 °C–26.85 °C) respectively, while surface pressures (specific humidity) are 550 hPa (10 g/kg) and 950 hPa (18 g/kg). The above conditions respectively are most favorable conditions for the occurrence of extreme precipitation in two regions. Moreover, near surface precipitation intensity could be intense under appropriate temperature, pressure and sufficient specific humidity even if CAPE is not large over the Tibetan Plateau. The anomalies of near surface atmospheric conditions related to extreme precipitation exhibit significantly abrupt changes within 6 h before and after the occurrence of extreme precipitation. These results indicate that the spatiotemporal distribution of extreme precipitation based on the GPM observations and the related near surface atmospheric conditions could be considered into forecast of extreme precipitation over the Tibetan Plateau in the future.

Modified photoplethysmography signal processing and analysis procedure for obtaining reliable stiffness index reflecting arteriosclerosis severity

Objective. This study aimed to describe a modified photoplethysmography (PPG) signal processing and analysis procedure to obtain a more reliable arterial stiffness index (SI). Approach. Three parameters were used to assess the PPG signal quality without prominent diastolic waves, which are similar to a sinusoidal waveform shape. The first parameter, sinusoidal ratio (S-value), was based on frequency-domain analysis: a higher S-value indicated the presence of PPG pulse wave with unapparent diastolic peak. The second parameter was the time difference between systolic peak-to-diastolic peak and the systolic peak-to-dicrotic notch. The third parameter was the percentage of sin-like waveform in the PPG signals. The applicability of these parameters was demonstrated in 40 participants, including 11 with apparent diastolic peaks in the PPG signals and 29 with unapparent diastolic peaks. Main results. An S-value of >3.5 indicated apparent diastolic peaks in the PPG signals. In addition, a systolic peak-to-diastolic peak time difference >80% and a sin-like waveform >55% may be associated with severity of vascular aging. Significance. These parameters successfully detected low-quality PPG signals with unapparent diastolic waveform before SI calculation, thereby ensuring the accuracy of subsequent evaluation of cardiovascular-related disease and clinical risk stratification.

The Comparison of Type of Music Tempo on Cardiopulmonary Function During Exercise

Purpose: The study aimed to examine the effects of beats per minute (BPM) on the cardiopulmonary functions of adult men during exercise and to provide reference materials for future physical therapy studies of the respiratory system.&#x0D; Methods: This study recruited 18 healthy male adults who agreed to participate in this study and had no cardiopulmonary problems. The participants conducted a total of five experiments with no music, 30 BPM, 130 BPM, 180 BPM, and 230 BPM, and music education was conducted regarding the music experience before the experiment. The experiment was conducted twice a week for a total of 3 weeks, and one-way analysis of variance was used to compare the mean differences in VO₂max, time, respiratory rate (RR), metabolic equivalents (METs), and peak time between each BPM.&#x0D; Results: For each BPM, the VO2max, time, RR, METs, and peak time showed significant differences. With 180 BPM, the VO₂max, time, RR, METs, and peak time were high. For each BPM, the VO₂max, time, RR, METs, and peak time showed significant differences. With 180 BPM, the VO₂max, time, RR, METs, and peak time were high.&#x0D; Conclusion: The results of this study show that the most effective BPM for cardiopulmonary functions is 180 BPM, and 180 BPM will enable to perform exercises more efficiently.

Instrumental responses and Pavlovian stimuli as temporal referents in a peak procedure.

Three experiments investigated whether the nature of the temporal referent affects timing behaviour in rats. We used a peak procedure and assessed timing of food well activity as a function of whether the referent was an instrumental response (a lever press that resulted in the withdrawal of the lever) or a conditioned stimulus (CS) that was 2 s in Experiment 1, 500 ms in Experiment 2, and 800 ms in Experiment 3. In all experiments, the interval between the offset of the temporal referent and food was 5 s. The curve fits for each experiment revealed no differences in peak time, but magazine responding immediately following the CS was higher than following a lever press. This pattern of results was interpreted as reflecting a combination of (a) ambiguity in which component of the 500 ms-2-s auditory stimulus was serving as the referent and (b) response competition between lever pressing and magazine activity. Critically, these results suggest that peak timing in rats is unaffected by whether a lever press or CS serves as the referent. This conclusion is consistent with theoretical models of timing behaviour, but not with evidence from humans showing that the subjective perception of time is affected by whether the cause of an outcome was self-generated or not.

The Relationship between Ultrasonographic Features of Hepatocellular Carcinoma and the Severity of Hepatocellular Carcinoma and the Expression of PTEN and Tg737.

To investigate the relationship between the ultrasonographic features of hepatocellular carcinoma (HCC) and the severity of HCC and the expression of tumor suppressor genes PTEN and Tg737, 90 patients with primary liver cancer are selected as the study subjects. The enhancement of liver tumor in arterial phase, portal venous phase, and delayed phase is observed by contrast-enhanced ultrasound (CEUS) before operation, and the echo intensity is compared with that of surrounding liver parenchyma. Immunohistochemistry is used to detect the expression of PTEN and Tg737 in hepatocellular carcinoma and paracancerous tissues. (1) In HCC, CEUS enhancement is characterized by rapid enhancement in arterial phase, enhancement in portal venous phase and delayed phase, and decreased hypoechoic changes. About 78.0% of the stage I-II liver cancer and 85.0% of the stage III-IV liver cancer show rapid enhancement and high echo in the arterial phase; only 8.0% of the stage I-II liver cancer shows moderate echo changes in the portal venous phase, while 32.5% (13/40) stage III-IV liver cancer shows moderate echo changes in the portal venous phase. (2) The positive rates of PTEN in liver cancer tissues and paracancerous tissues are 21.1% (19/90) and 70.0% (63/90), respectively, and the difference is statistically significant. The positive rates of Tg737 in liver cancer tissues and paracancerous tissues are 17.8% (16/90) and 75.6% (68/90), respectively, and the difference is statistically significant. Compared with PTEN and Tg737 negative groups, the ascending slope (RS) and initial elimination time (WT) of PTEN and Tg737 positive groups are significantly higher, indicating that the inflow velocity of contrast medium in the positive group is higher, the outflow time is shorter, and the lesions shows low enhancement rapidly. However, the expression of PTEN and Tg737 had no significant difference in maximal intensity (IMAX), peak time (TTP), and mean transit time (mTT). (3) Correlation analysis shows that the immunohistochemical scores of PTEN and Tg737 are not significantly correlated with IMAX, mTT, and TTP but positively correlated with RS (r = 0.359,P < 0.05), suggesting that the positive expressions of PTEN and Tg737 are negatively correlated with the inflow velocity of contrast medium. The immunohistochemical scores of PTEN and Tg737 are negatively correlated with WT, which indicated that the higher the expression intensity of PTEN is, the longer the outflow time of contrast medium is and the slower the outflow of contrast medium is. There is a significant correlation between the expression of PTEN and Tg737 proteins and CEUS parameters in hepatocellular carcinoma.