Moving fast, thinking fast:The relations of physical activity levels and bouts to neuroelectric indices of inhibitory control in preadolescents

Background:Structured vigorous physical activity(VPA)can improve cognitive control in children,but studies relating daily physical activity(PA)to cognitive control have yielded conflicting findings.While objectively measured daily PA summarizes all occurrences of PA within a registered period,a minimum duration of continuous PA is required for registration of a PA bout.Because brief bouts of high-intensity PA can account for a large proportion of children’s daily activity-related energy expenditure,this study assessed whether daily and bouted VPA were selectively related to cognitive control in preadolescents relative to other PA intensities.Methods:A total of 75 children between the ages of 8 and 10 years(49%girls)wore an ActiGraph wGT 3 X+on the hip for 7 days.The acceleration signal from the vertical axis was summarized over 1 s,5 s,and 15 s epochs.Daily and boutecd modercate PA,moderate-to-vigorous PA,and VPA were measured.PA bouts were expressed as the frequency and time spent in 2 different continuous PA bouts,one lasting≥10 s and the other lasting≥30 s at a given intensity.Inhibitory control was assessed using behavioral responses to a modified flanker task(mean reaction time(RTmean)and accuracy).Attentional resource allocation and co gnitive processing speed were measured using the amplitude and latency of the P3 component of event-related brain potentials,respectively.Associations between PA,behavioral indices of inhibitory control,P3 amplitude,and latency were assessed using hierarchical regression models.Results:Daily VPA was not related to RTmean or accuracy on either congruent or incongruent trials.In contrast,more time spent in VPA bouts lasting≥30 s predicted shorter P3 latency across epochs and flanker congruencies(allβ≤-0.24,all p≤0.04).The associations between shorter P3 latency and the time spent in moderate-to-vigorous PA bouts lasting≥30 s were less consistent and largely limited to congruent trials(congruent:β(-0.3 1,-0.34)).No significant associations were observed upon correction for false discovery rate.Conclusion:The pattern of uncorrected associations aligns with the dose-response literature and suggests that brief VPA bouts may yield the greatest benefits to cognitive processing speed in preadolescents.Future studies using measures of brain structure and function are needed to understand the mechanisms linking bouted VPA to neurocognitive function during childhood.

径向湍性输运条件下CFETR平行热通量及包层能量沉积模拟

采用BOUT++输运程序与PFCFlux程序的耦合对CFETR包层第一壁上的能量沉积情况进行了模拟。研究发现,当湍性输运系数为50m^(2)·s^(-1)时,最外闭合磁面上的极向平均平行热通量为14058.5MW·m^(-2),进入刮削层的等离子体功率Psol的值为197.4MW;CFETR包层第一壁上的能量沉积主要集中于真空室壁靠近中心螺线管的高场侧区域,最大热通量出现在这一区域的中间部分。

Numerical simulation of impact of supersonic molecular beam injection on edge localized modes

A three-field model with the impact of supersonic molecular beam injection(SMBI) based on the BOUT++ code is built to simulate edge localized modes(ELMs). Different parameters of SMBI are explored to find an optimal SMBI scenario for ELM mitigation. The linear simulations show that the growth rate of peeling-ballooning mode is reduced by SMBI. The reduction amplitude of the growth rate is increased when the amplitude or width of SMBI is increased, and when SMBI is deposited at the top, bottom and middle of the pedestal, the reduction amplitude increases successively. The nonlinear simulations show that the ELM size is reduced by SMBI. The reduction amplitude of the ELM size is increased when the amplitude or width of SMBI is increased, and when SMBI is deposited at the bottom, top and middle of the pedestal, the reduction amplitude increases successively. Surface-averaged pressure profiles and filamentary structures are analyzed when the ELMs erupt. Deep deposition of SMBI such as at the top and middle of the pedestal reduces the inward collapse amplitude of the pressure profiles, which can improve the confinement efficiency during ELMs. Shallow deposition of SMBI such as at the middle and bottom of the pedestal reduces the outer extent of the filamentary structures, which can slow down the erosion of plasma-facing components caused by ELMs. In conclusion,shallow deposition of SMBI with sufficient amplitude and width can meet the needs of ELM mitigation.

The BOUT Project; Validation and Benchmark of BOUT Code and Experimental Diagnostic Tools for Fusion Boundary Turbulence

A boundary plasma turbulence code BOUT is presented. The preliminary encour- aging results have been obtained when comparing with probe measurements for a typical Ohmic discharge in HT-7 tokamak. The validation and benchmark of BOUT code and experimental diagnostic tools for fusion boundary plasma turbulence is proposed.

Myofiber Permeability and Force Production of Rat Muscles Following Eccentric Contractions: The Repeated Bout Effect Depends on the Interval

Past eccentric contraction (ECC)-induced muscle injury reduces the severity of symptoms of subsequent muscle injury;this phenomenon is known as a repeated bout effect (RBE). It has been reported that increases in the duration of the interval between the first and second bouts are linked to weakening of the RBE. However, the histology following the attenuation of the RBE remains unclear. We examined the sustained effects of the second bout with regard to myofiber permeability and muscle force. Sixty-four male rats were randomly assigned to eight groups that varied in the number of exercise sessions and the duration of the interval between the first and second bouts: the non-ECC (Control);the single-injury (Post 1st bout);groups that were allowed to recover for 1, 2, and 4 weeks after a single injury (Pre 2nd bout_1w, Pre 2nd bout_2w, and Pre 2nd bout_4w);and groups that were subjected to second injuries 1, 2, and 4 weeks after the first (Post 2nd bout_1w, Post 2nd bout_2w, and Post 2nd bout_4w). The tibialis anterior was electrically stimulated in each ECC group. Twenty-four hours before muscle sampling, Evans blue dye (EBD) (a marker of myofiber damage) was administered. The maximal isometric contraction tension was measured immediately before sampling. The number of EBD-positive (+) fibers was determined via histological analysis. An RBE was revealed by functional examination at the 1- and 2-week and histological examination at the 1-, 2-, and 4-week time points (P < 0.05). In terms of myofiber permeability, prolongation of the interval before the second bout weakened this effect (P < 0.05). Experiments with 1-, 2-, and 4-week intervals indicated that prolongation of the interval before the second bout weakened the RBE with regard to myofiber permeability.

托卡马克边界局域模的初步模拟研究

磁约束核聚变是解决能源危机的最佳方法,托卡马克已经成为受控热核聚变最有可能成功的装置。高约束模式(H模)下自发产生的边界局域模(ELM)在爆发时携带的大量粒子和能量会对装置的第一壁材料造成很大的损坏。因此,本文在分析H模及ELM的基本物理图像和特征基础上,利用BOUT++模拟程序对ELM进行了初步分析,结果发现,抗磁效应能很好地抑制ELM不稳定性的增长率。

Comparison of transport coefficients before and after density pump-out induced by resonant magnetic perturbation using a BOUT++ six-field model on the EAST tokamak

Many experiments have demonstrated that resonant magnetic perturbation(RMP) can affect the turbulent transport at the edge of the tokamak. Through the Experimental Advanced Superconducting Tokamak(EAST) density modulation experiment, the particle transport coefficients were calculated using the experimental data, and the result shows that the particle transport coefficients increase with RMP. In this study, the six-field two-fluid model in BOUT++ is used to simulate the transport before and after density pump-out induced by RMP,respectively referred as the case without RMP and the case with RMP. In the linear simulations,the instabilities generally decreases for cases with RMP. In the nonlinear simulation, ELM only appears in the case without RMP. Additionally, the particle transport coefficient was analyzed,and the result shows that the particle transport coefficient becomes larger for the case with RMP,which is consistent with the experimental conclusion. Moreover, its magnitude is comparable to the results calculated from experimental data.

Effect of repeated eccentric exercise on muscle damage markers and motor unit control strategies in arm and hand muscle

To examine the contralateral repeated bout effect(CL-RBE)on muscle damage markers and motor unit(MU)control strategies,seventeen healthy adults performed two bouts of 60 eccentric contractions with elbow flexor(EF group;n=9)or index finger abductor(IA group;n=8)muscles,separated by 1 week.All participants randomly performed eccentric exercise on either the right or left arm or hand muscles,and muscle damage markers and submaximal trapezoid contraction tests were conducted pre,post,1-and 2-day post eccentric protocol.One week after the first bout,the same exercise protocol and measurements were performed on the contralateral muscles.Surface electromyographic(EMG)signals were collected from biceps brachii(BB)or first dorsal interosseous(FDI)during maximal and submaximal tests.The linear regression analyses were used to examine MU recruitment threshold versus mean firing rate and recruitment threshold versus derecruitment threshold relationships.EMG amplitude from BB(bout 1 vs.bout 2=65.71%±22.92%vs.43.05%±18.97%,p=0.015,d=1.077)and the y-intercept(group merged)from the MU recruitment threshold versus derecruitment threshold relationship(bout 1 vs.bout 2=7.10±14.20 vs.0.73±16.24,p=0.029,d=0.513)at 50%MVIC were significantly different between two bouts.However,other muscle damage markers did not show any CL-RBE in both muscle groups.Therefore,despite changes in muscle excitation and MU firing behavior,our results do not support the existence of CL-RBE on BB and FDI muscles.