Transition Time Interval Research Articles

Effect of high-frequency repetitive transcranial magnetic stimulation on swallowing function and pneumonia in poststroke dysphagia in rats

BackgroundPost-stroke dysphagia (PSD) is a common symptom of stroke. Clinical complications of PSD include malnutrition and pneumonia. Clinical studies have shown that high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) can improve the swallowing function in stroke patients. However, few studies have elucidated the underlying molecular mechanisms. MethodsA PSD rat model was established using transient middle cerebral artery occlusion (tMCAO). Rats were randomly divided into sham-operated groups, PSD groups, PSD + sham-rTMS groups, PSD + 5 Hz-rTMS groups, PSD + 10 Hz-rTMS groups and PSD + 20 Hz-rTMS groups. Rats were weighed and videofluoroscopic swallowing studies were conducted. Pulmonary inflammation, levels of substance P (SP) and calcitonin gene-related peptide (CGRP) in the serum, lung, and nucleus tractus solitarius (NTS), brain-derived neurotrophic factor (BDNF) and 5-hydroxytryptamine (5HT) in NTS were evaluated. ResultsRats in the PSD group experienced weight loss, reduced bolus area and pharyngeal bolus speed, and increased pharyngeal transit time (PTT) and inter-swallow interval (ISI) on day 7 and day 14 after operation. Moreover, PSD rats showed pulmonary inflammation, reduced levels of SP in the lung and serum, increased levels of CGRP in the lung and NTS, reduced levels of BDNF and 5HT in the NTS. There was no significant difference between the PSD group and the PSD + sham-rTMS group in the results of weight and VFSS. Comparing with the PSD group, there significant increases in the bolus area, decreases in PTT of rats following 5 Hz rTMS intervention. HF-rTMS at 10 Hz significantly increased the weight, bolus area, pharyngeal bolus speed and decreased the PTT and ISI of rats. There were also significant increases in the bolus area (p < 0.01) and pharyngeal bolus speed, decreases in PTT and ISI of rats following 20 Hz rTMS intervention. Furthermore, compared with the PSD + 5 Hz-rTMS group, there were significant increases in the bolus area and pharyngeal bolus speed, decreases in ISI in the swallowing function of rats in the PSD + 10 Hz-rTMS group. Besides, compared with the PSD + 5 Hz-rTMS group, there were significant decreases in ISI in the swallowing function of rats in the PSD + 20 Hz-rTMS group. HF-rTMS at 10 Hz alleviated pulmonary inflammation, increased the levels of SP in the lung, serum, and NTS, CGRP in the serum and NTS, 5HT in the NTS of PSD rats. ConclusionCompared with 5 Hz and 20 Hz rTMS, 10 Hz rTMS more effectively improved the swallowing function of rats with PSD. HF-rTMS at 10 Hz improved the swallowing function and alleviated pneumonia in PSD rats. The mechanism may be related to increased levels of SP in the lung, serum and NTS, levels of CGRP in the serum and NTS, 5HT in the NTS after HF-rTMS treatment.

A new path integration method for the stochastic system under Poisson white noise excitation based on a probability mapping

In this paper, a new path integration method is proposed for stochastic dynamical systems excited by Poisson white noise. An efficient one-step transition probability density function (TPDF) matrix is constructed based on a decoupling probability mapping. The new method can handle the case of multiple impulses occurring in a one-step transition time interval and considers the randomness of the impulse instant, which compensates for a drawback of previous path integration methods. The probability mapping realizes the decoupling of randomness and the one-step TPDF matrix, which can be extended to general stochastic systems satisfying the Markov property. The stochastic responses of two dynamical systems excited by Poisson white noises for different mean arrival rates are obtained by using the new path integration method, and MC simulations prove that the new method is very effective, and it maintains good accuracy even for large mean arrival rates.

A Bayesian perspective of middle-batting position in ODI cricket

The cricket fraternity described “an unsettled batting position of number four” as one of the major causes for India’s exit from International Cricket Council Men’s World Cup 2019. Consistent chopping and changing batsmen at the sensitive fourth batting position proved to be a disaster for team India then. Therefore, ranking of all the batsmen, in the then Indian cricket team, who were deemed to be eligible for this position remained a much-debated issue both before and after the World Cup 2019. In the present paper, Kaplan-Meir curves are used to make multiple comparisons for respective batting performances among the batsmen who have ever played in the middle order position. In this paper, frailty of these batsmen is studied through Bayesian analysis at the start of their innings and during the time-interval of transition to their best playing ability by considering respective run scores. Posterior summaries of innate player ability are obtained by deploying a Markov Chain Monte Carlo algorithm which is then used to assess and compare the individual batting performances. Estimation of incomplete innings is handled via censoring strategies.

A rapid warning method for wildfire occurrences along the transmission corridor driven by power system monitoring data

This paper focuses on the problems of frequent wildfire occurrences along the transmission corridor and the lack of accurate and timely monitoring means for early warnings. Furthermore, this paper evaluates the rapid warning method for wildfire occurrences along the transmission corridor driven by power system monitoring data. First, we established the relationship between the historical data of wildfires along the transmission corridor and the operating state information of a power grid based on the Apriori association rule algorithm; the characteristic signals of the transmission line when wildfires occur were mined. Second, based on the characteristics of the time distribution of wildfire occurrences along the transmission corridor, a nonlinear regression model was created to further improve the prediction accuracy. Finally, by combining the characteristic signals and time distribution characteristics, we developed an early warning method. This method not only addresses the challenges faced by meteorological satellite remote sensors caused by the weather, the long transit time interval, and the high cost of adding sensors, but it also realizes the remote and rapid early warning of wildfires along the transmission corridor. Finally, a case study of practical data of a certain area in southwest China is used to verify the proposed method. The results show the high accuracy and timeliness of the proposed method.

Statistical model calculation of the compound nuclear fission timescale in fusion-fission reactions

In the decay of an excited heavy nucleus, both the fission or evaporation residue (ER) cross sections and the fission time are determined by the competition between the various evaporation channels and fission. Statistical model (SM) calculations for several heavy-ion-induced fusion-fission reactions are presented which reproduce the fission or ER excitation functions. The corresponding calculated fission times are found to depend upon the compound nuclei and their excitation energies. The multichance fission probabilities and the corresponding fission times are also obtained, and they are shown to depend sensitively on the shell correction energies and the neutron separation energies of the compound nuclei involved. The experimental neutron multiplicities are reproduced by adjusting the saddle-to-scission transition time interval. An additional delay time for compound nuclear formation is found necessary to fit the experimental neutron multiplicities for a system with higher entrance channel mass symmetry.

On the ideal groundwater sampling window by utilizing transition pumping period

A new method of groundwater sampling has recently been proposed, which involves two-phase well purging – a high-flow rate pumping phase followed by low flow rate purging and sampling. The high pumping rate yields a rapid well drawdown and enhances hydraulic gradients within the aquifer. After switching to a low pumping rate, the stressed flow field is maintained to prevent the water in the well casing from moving downwards to bias the collected samples. This study addresses two practical issues that are critical for applying such a sampling method: the determination of the pumping switch time and the transition time interval available for groundwater sampling. We use Theis and Papadopulos solutions to study the impact of wellbore storage on the correlation between switch time and transition time interval. By imposing critical conditions to the derived solutions, we suggest that the transition time interval is solely associated with the switch time. Results show that a later switch time yields a longer transition time interval. Theis solution provides an approximate linear relationship between the switch time and the transition time interval, which can be used as a simple approximate practical guideline. Results from Papadopulos solution confirm the linear relationship at late times and provide a more accurate relationship for early times by accounting for the well storage impact. A sensitivity analysis indicates that aquifers with smaller storativity under a higher pumping ratio will generate a longer transition time interval given the same switch time. Similarly, an earlier switch time is allowed given a predefined transition time interval. This study presents a guideline to determine reasonable switch time under various aquifer hydrogeologic conditions and estimate the ideal groundwater sampling window.

On the bipolarity of Wolf–Rayet nebulae

ABSTRACT Wolf–Rayet stars are amongst the rarest but also most intriguing massive stars. Their extreme stellar winds induce famous multiwavelength circumstellar gas nebulae of various morphologies, spanning from circles and rings to bipolar shapes. This study is devoted to the investigation of the formation of young, asymmetric Wolf–Rayet gas nebulae and we present a 2.5-dimensional magneto-hydrodynamical toy model for the simulation of Wolf–Rayet gas nebulae generated by wind–wind interaction. Our method accounts for stellar wind asymmetries, rotation, magnetization, evolution, and mixing of materials. It is found that the morphology of the Wolf–Rayet nebulae of blue supergiant ancestors is tightly related to the wind geometry and to the stellar phase transition time interval, generating either a broadened peanut-like or a collimated jet-like gas nebula. Radiative transfer calculations of our Wolf–Rayet nebulae for dust infrared emission at $24\, \mu \rm m$ show that the projected diffuse emission can appear as oblate, bipolar, ellipsoidal, or ring structures. Important projection effects are at work in shaping observed Wolf–Rayet nebulae. This might call a revision of the various classifications of Wolf–Rayet shells, which are mostly based on their observed shape. Particularly, our models question the possibility of producing pre-Wolf–Rayet wind asymmetries, responsible for bipolar nebulae like NGC 6888, within the single red supergiant evolution channel scenario. We propose that bipolar Wolf–Rayet nebulae can only be formed within the red supergiant scenario by multiple/merged massive stellar systems, or by single high-mass stars undergoing additional, e.g. blue supergiant, evolutionary stages prior to the Wolf–Rayet phase.

Direct numerical simulation of turbulent flow and heat transfer in a hexagonal rod bundle

The aspects of numerical simulation of heat transfer in a flow along the hexagonal rod bundle are discussed in the present work. The direct numerical simulation is used to investigate the flow with Reynolds and Prandtl numbers varying in the range from 2500 to 10000 and 0.0043 to 7 correspondingly. The obtained simulation results demonstrate good agreement with available experimental data and semi-empirical correlations for the thermo-hydraulic characteristics of the channel. The empirical correlations for the Nusselt number distributions summarizing the results of the numerical simulations are proposed. The preliminary calculations have shown that the modelled time averaging interval is comparable with the initial transition time interval. This observation allows applying the approach, proposed in [7], to speed up the simulations.

A novel approach for non-invasive measurement of mean arterial pressure using pulse transit time

Recent days many researches are carried out related to the heart of the human. As a result many remedies are found for the various heart disorders. Electrocardiography (ECG) is the exertion of the electrical response from heart by placing the electrodes over the chest. The Einthoven triangle is an imaginary formation of the three leads in the triangle used in electrocardiography; by that technique of placement of electrode we can analysis the electrocardiogram of the heart. The waveform is also known as PQR waveform which contains the information of arterial repolarization, arterial polarization, ventricular repolarization and ventricular polarization. In general the BP monitor is carried out using oscillometry. In the existing system separate techniques and devices are used to measure electrocardiography and BP. The proposed system is to integrate both electrocardiography and blood pressure measurement by means adopting transit pulse time. It is defined as the systematic time lay off betwixt oscillometric pulses and peaks of ECG especially R peaks of it. The major advantage of the system is to exhibit non-zero crossing and gives more accurate result. The mean arterial pressure estimation is done by using MatLab which is the unique estimation method for measuring pulse transit time interval. Thus the non invasive system designed which reduce the cuff deviations and errors in electrocardiography. It can be applied in detecting the arterial disorders at most efficient manner.

Characterizing queries in cross-device OPAC search: a large-scale log study

PurposeThe study focused on online public access catalog (OPAC) users’ cross-device search behavior. The purpose of this paper is to understand the characteristics of cross-device OPAC searches, and to identify query reformulation (QR) patterns during device transitions.Design/methodology/approachThe transaction log from a university library, spanning six months, was used to conduct the quantitative analysis. The query vocabulary richness, which refers to the average number of unique words each query contains in a search session, can evaluate query diversity, and contribute to the analysis of QR.FindingsThe results show that PC-PC transition is the most important pattern of device transition. The time interval of device transition was different to the time interval of transitions in web searches. Short device transitions mainly occurred in daytime, and the number of transitions that occurred in less than one minute was higher than on the web. Searches for Industry and Technology triggered the most device transitions, and the users tended to choose the same search field. In addition, the authors made a detailed analysis of the reasons for same-type device transitions and different-type device transitions. Furthermore, the authors focused on the characteristics of adjacent QR patterns. The authors not only refined the concept of cross-device to include the same-type device transition, but also summarized the characteristics of the cross-device QR patterns, which can be used to predict post-switch queries.Originality/valueThis study extends research into cross-device interaction and cross-device search to the domain of digital library research. The authors also introduced QR perspective on cross-device interaction on OPAC.

Problem on the brachistochronic motion of a heavy disk with dry friction

The plane motion of a heavy dynamically symmetric circular disk (wheel) touching a supporting regular material curve with no more than one disk periphery point at any instant, is considered. At the instantaneous contact point between the disk and the curve the force of the Coulomb (dry) friction acts. The problem on finding the form of a supporting curve that provides the minimal transition time interval for the disk center which starts at a given position A, when the disk is in rest, and finishes at a given terminal position B, is treated. The method of the conditional variational problem with differential inequalities is used to find the necessary conditions satisfied with the desired curve.

The Effect of a Pediatric Intensive Care Severity-Tiered Pathway for Status Asthmaticus on Quality Measures and Outcomes.

Background: Patients with status asthmaticus admitted to the hospital contribute tremendous costs to the healthcare system. Treatment protocols directed at improving care to pediatric inpatients have improved both clinical and financial outcomes; however, there are limited data demonstrating the impact of goal-driven therapy for patients with status asthmaticus in the pediatric intensive care unit (PICU). The purpose of this initiative was to standardize care of children with status asthmaticus in the PICU to improve clinical outcomes. Materials and Methods: A goal-directed clinical pathway using a validated pediatric asthma severity score was developed. A pre-post intervention assessed patients 2-17 years of age admitted to the PICU with status asthmaticus. The effect of the protocol was measured from October 2015 to October 2016. The primary outcome was the transition time interval from continuous nebulized bronchodilator therapy to every 2 hourly intermittent treatments. Secondary outcomes related to treatment options and clinical complications were also assessed. Results: Postintervention patient (n = 124) demographics were similar to those in the preintervention group (n = 130). Compared with baseline, there was a 4.9-h decrease in the mean transition time from continuous to intermittent bronchodilator use (31.9 versus 27.0, P = 0.033) following the intervention. The mean and median hospital length of stay (LOS) was significantly decreased in the postintervention group by 14.76 h (P = 0.011) and 16.68 h (P = 0.003). There were no readmissions to the PICU in the postintervention group. The use of rescue BiPAP (Bi-level positive airway pressure ventilation) was significantly higher in the preintervention group compared with the postintervention group (42% versus 28%, P = 0.036). Conclusions: A severity-tiered, goal-driven treatment pathway for pediatric patients admitted to the PICU with status asthmaticus reduced the time required to transition from continuous to intermittent inhaled bronchodilator use. As a result, overall hospital LOS was significantly decreased with no increase in clinical complications.

Nonspherical sub-millimeter gas bubble oscillations: Parametric forcing and nonlinear shape mode coupling

The nonspherical oscillations of a gas bubble being forced by a sinusoidal pressure field in an axisymmetric geometry are considered using an asymptotic model, which accounts for nonlinear shape mode interactions to third order, the effects of viscosity (in the absence of vorticity) to the same order, and weak compressibility. In particular, conditions by which a parametrically forced sub-millimeter sized bubble can achieve stable oscillatory shape deformation are studied in detail. It is found that a combination of the transfer of energy from the parametrically forced shape mode to the other modes through nonlinear shape mode coupling and viscous damping is key. Two transition regions in the spherical oscillations of the bubble are identified, the first being a consequence of the damping effects of compressibility and viscosity (with compressibility acting on a faster time scale) and the second due to nonlinear shape mode interactions. During this second transition time interval, the parametrically forced shape mode grows rapidly and nonlinearly excites other shape modes. For the moderate driving pressures considered, this growth is shown to peak and following a stabilizing transition region (only observed for the n ≥ 3 shape modes), the bubble thereafter undergoes stable, oscillatory shape deformation. Though the resultant shape deformation is dominated by the parametrically forced mode n = i, it is found to be a combination of a number of shapes modes, where the next most important mode is the second harmonic, n = 2i shape mode.

Performance evaluation of downlink packet scheduling for real time traffic in LTE system

Long-term evolution (LTE) is one of the promising broadband wireless technologies developed by third generation partnership project (3GPP) to support higher data rate. Packet scheduling is one of the open issues in deciding the overall system performance. In this paper, a new scheduling scheme is proposed that is suitable for real time services. In this method, two metrics are estimated for the packets based on the type of bearers. Tmax is calculated for guaranteed bit rate (GBR) bearers and Tmin is calculated for non-GBR bearers. The main objective is to allocate first all GBR bearers because of their highest quality-of service (QoS) requirements. After the resource allocation of GBR bearers, if the current transit time interval (TTI) has more resources, then the packets of non-GBR bearers are entertained. The proposed scheme is compared with traditional scheduling algorithms and validated by means of simulation results.

Performance evaluation of downlink packet scheduling for real time traffic in LTE system

Long-term evolution (LTE) is one of the promising broadband wireless technologies developed by third generation partnership project (3GPP) to support higher data rate. Packet scheduling is one of the open issues in deciding the overall system performance. In this paper, a new scheduling scheme is proposed that is suitable for real time services. In this method, two metrics are estimated for the packets based on the type of bearers. Tmax is calculated for guaranteed bit rate (GBR) bearers and Tmin is calculated for non-GBR bearers. The main objective is to allocate first all GBR bearers because of their highest quality-of service (QoS) requirements. After the resource allocation of GBR bearers, if the current transit time interval (TTI) has more resources, then the packets of non-GBR bearers are entertained. The proposed scheme is compared with traditional scheduling algorithms and validated by means of simulation results.

Altered characteristics of balance control in obese older adults

Obesity is one of the most significant epidemiological trends of the last decades. Recently it was found that obese individuals show postural instability. Balance control mechanisms in obese older adults were less studied. Therefore we aimed to investigate the effect of obesity on balance control mechanisms in older adults. Parameters from Stabilogram-Diffusion Analysis (SDA) and measures from summary statistics of foot centre-of-pressure (COP) displacements along the anterior-posterior (AP) and mediolateral (ML) directions in eyes open and eyes closed conditions were used to characterize postural control in 22 obese (30-<35kg/m(2)), 26 overweight (25-<30kg/m(2)), and 18 normal weight subjects (18.5-<25kg/m(2)). Obese group subjects demonstrated significantly greater transition displacement, transition time interval, and short-term scaling exponent in the ML-direction compared with the normal weight group (eyes open and closed). In the AP-direction the obese group showed greater transition displacement (eyes open) and short-term scaling exponent (eyes open and closed). Average AP-COP and ML-COP ranges of COP sway were higher in the obese group compared with the normal weight group (eyes open and closed). This work indicates an altered postural control process in obese older adults. A greater sway displacement before closed-loop feedback mechanisms are called into play was seen in the ML direction that may lead to a higher risk of instability and fall events.

Analysis of small intestinal transit and colon arrival times of non-disintegrating tablets administered in the fasted state

In this study individual data on tablet gastrointestinal transit times (i.e. gastric emptying, small intestinal transit, ileocecal junction residence, and colon arrival times) were obtained from literature in order to present and analyze their distributions and relationships. The influence of the time of food intake after tablet administration in fasted state on gastrointestinal transit times was additionally evaluated.There were 114 measurements from subjects who received the first meal at 4h after tablet administration. Approximately 32% of the tablets arrived into the colon before the meal intake at 4h. An evident increase in the frequency of colon arrival of tablets within 40min after the meal intake at 4h post-dose was observed, where approximately 39% of all tablets arrived into the colon. This is in accordance with findings described in literature where a meal ingested several hours post-dose accelerates tablet transit through the terminal ileum and shortens the transit through the small intestine. The median (min, max) of gastric emptying, small intestinal transit, and colon arrival times in the group where the first meal intake was at 4h post-dose is 35 (0,192), 215 (60,544), and 254 (117,604) minutes, respectively. The dependence of colon arrival times on gastric emptying times was described by the nonparametric regression curve, and compared with the presumed interval of colon arrival times, calculated by summation of observed gastric emptying times and frequently cited small intestinal transit time interval, i.e. 3–4h. For shorter gastric emptying times the trend of colon arrival times was within the presumed interval. At short gastric emptying times many observation points are also within the presumed interval since this interval coincides with short period after meal intake at 4h post-dose. Additionally, in numerous occasions relatively long ileocecal junction residence times were obtained, which may be important information from the point of view of drug absorption. The findings of gastrointestinal transit times are important and should be taken into consideration when predicting the in vivo performance of dosage forms after oral administration.

A time–frequency approach to estimate critical time intervals in postural control

The critical time interval (CTI) is a parameter that has been used to distinguish open-loop from closed-loop control during upright stance. The aim of this study was to develop a new method to determine CTIs. The new approach, termed the intermittent critical time interval (ICTI) method, was motivated from evidence that upright standing is an intermittent rather than an asymptotic stability control process. For this ICTI method, center-of-pressure time series are first transformed to the time–frequency domain with a wavelet method. Subsequently, the CTI is assumed equal to the time span between two local maxima in the time–frequency domain within a distinct frequency band (i.e., 0.5–1.1 Hz). This new method may help facilitate better estimates of the transition time interval between open and closed-loop control during upright stance and can also be applied in future work such as in simulating postural control. In addition, this method can be used in future work to assess temporal changes in CTIs.

Three-dimensional numerical simulation of nonlinear acoustic-gravity wave propagation from the troposphere to the thermosphere

Three-dimensional nonlinear breaking acoustic-gravity waves (AGWs) propagating from the Earth's surface to the upper atmosphere are simulated numerically. Horizontally moving periodical structures of vertical velocity on the Earth's surface are used as AGW sources in the model. The 3D algorithm for hydrodynamic equation solution uses finite-difference analogues of basic conservation laws. This approach allows us to select physically correct generalized wave solutions of hydrodynamic equations. The numerical simulation covers altitudes from the ground up to 500 km. Vertical profiles of the mean temperature, density, molecular viscosity, and thermal conductivity are specified from standard models of the atmosphere. Atmospheric waves in a few minutes can propagate to high altitudes above 100 km after activation of the surface wave forcing. Surfaces of constant phases are quasi-vertical first, and then become inclined to the horizon below about 100 km after some transition time interval. Vertical wavelengths decrease with time and tend to theoretically predicted values after times longer than several periods of the wave forcing. Decrease in vertical wavelengths and increase in AGW amplitudes can lead to wave instabilities, accelerations of the mean flow and wave-induced jet streams at altitudes above 100 km. AGWs may transport amplitude modulation of atmospheric wave sources in horizontal directions up to very high levels. Low wave amplitudes in the beginning of transition processes after activation of atmospheric wave sources could be additional reasons for slower amplitude grows with height compared to the nondissipative exponential growth predicted for stationary linear AGWs. Production of wave-induced mean jets and their superposition with nonlinear unstable dissipative AGWs can produce strong narrow peaks of horizontal speed in the upper atmosphere. This may increase the role of transient nonstationary waves in effective energy transport and variations of atmospheric parameters and gas admixtures in a broad altitude range.

Comparison of pulse pressure variation with radial arterial systolic, diastolic and pulse transit time interval variation in pediatric patients undergoing liver transplantation

In pediatric patients, dynamic preload indices to predict fluid responsiveness have conflicting results in comparison with adults. A recent study demonstrated that pulse pressure variation (PPV) ≥16% has provided an accurate method for predicting fluid responsiveness in pediatric congenital heart surgery. We aimed to compare PPV and respiratory systolic, diastolic and pulse transit time interval variation (STV, DTV and PTTV, respectively) as predictors of fluid responsiveness during pediatric liver transplantation.