Time Behavior Research Articles

Long time behavior of solutions of an electroconvection model in $${\mathbb {R}}^2$$

Long time behavior of solutions of an electroconvection model in $${\mathbb {R}}^2$$

Exploring the Early Time Behavior of the Excited States of an Archetype Thermally Activated Delayed Fluorescence Molecule.

Optical pump-probe techniques allow for an in-depth study of dark excited states. Here, we utilize them to map and gain insights into the excited states involved in the thermally activated delayed fluorescence (TADF) mechanism of a benchmark TADF emitter DMAC-TRZ. The results identify different electronic excited states involved in the key TADF transitions and their nature by combining pump-probe and photoluminescence measurements. The photoinduced absorption signals are highly dependent on polarity, affecting the transition oscillator strength but not their relative energy positions. In methylcyclohexane, a strong and vibronically structured local triplet excited state absorption (3LE → 3LEn) is observed, which is quenched in higher polarity solvents as 3CT becomes the lowest triplet state. Furthermore, ultrafast transient absorption (fsTA) confirms the presence of two stable conformers of DMAC-TRZ: (1) quasi-axial (QA) interconverting within 20 ps into (2) quasi-equatorial (QE) in the excited state. Moreover, fsTA highlights how sensitive excited state couplings are to the environment and the molecular conformation.

Assessing dependence between land use/land cover and water quality

Changes in land use/land cover (LULC) directly or indirectly affect water quality in watercourses and impoundments. Sustainable management strategies aimed to enhance ecosystem health and community well-being require an accurate water-quality evaluation. This study looks into the correlation between temporal changes in LULC, represented by selected landscape variables (land cover area and proportion, patch density, Euclidean nearest-neighbor distance, mean shape index, and Shannon index), and water quality variables (nitrate, total phosphorus, and total suspended solids) at catchment scale. To compare the watershed-size influence, this analysis was performed at two different spatial scales represented by two Uruguayan basins of different sizes, San Salvador (3,118 km2) and Del Tala (160 km2). Partial Least Squares and Random Forest unsupervised machine-learning models were employed for this analysis. By exploiting a non-model-biased method based on game theory (SHAP), the LULC characteristics were quantified and ranked based on their level of importance in the water-quality evaluation. The main outcomes of this study proved that patch density is one of the most influencing metrics in both watersheds and for both models. Agricultural land use is the most critical one at both catchments and agricultural with a forage crop land uses are the most important ones for both algorithms. Furthermore, it is possible to state that the adopted techniques are valuable tools that can provide an adequate overview of the water‐quality behavior in space and time and the correlations between water-quality variables and LULC.

The long time behavior of the fractional Ornstein-Uhlenbeck process with linear self-repelling drift

The long time behavior of the fractional Ornstein-Uhlenbeck process with linear self-repelling drift

Existence of polynomial attractor for a class of extensible beams with nonlocal weak damping and critical nonlinearity

The goal of this paper is to study the long time behavior of the extensible beams equation with the nonlocal weak damping . In the case of critical growth of the nonlinearity, the polynomial attractor which can quantitatively describe the attractive rate of attractors for the equation is studied. The work generalizes and improves previous results for the extensible beams equation.

Insight into the nucleation behavior of tiamulin hydrogen fumarate methanol solvate in methanol-ethyl acetate binary mixtures

To investigate the nucleation behavior of tiamulin hydrogen fumarate methanol solvate (THFMS), the solubility, induction time, and metastable zone width (MSZW) of THFMS in methanol-ethyl acetate binary mixtures were measured. The nucleation potential model, which is based on the classical nucleation theory and correlates the induction time and MSZW, has been employed to deal with the experimental data and estimate the interfacial energy and the critical nucleation potential. The estimated values determined from the nucleation potential model are in accordance with the experimental values. The interfacial energy and the critical nucleation potential of THFMS steadily decrease with the increasing saturation temperature, whereas those of THFMS initially decrease and subsequently increase as the ethyl acetate content increases. The results demonstrate that an increase in saturation temperature leads to enhanced nucleation favorability, while the difficulty of nucleation initially decreases and then increases with increasing ethyl acetate content. Furthermore, the critical nucleation parameters, including the critical Gibbs free energy, the critical nucleus size, and the critical number of molecules in a nucleus, exhibit the same trend in alterations regarding both saturation temperature and ethyl acetate content.

Information Propagation Prediction Based on Spatial–Temporal Attention and Heterogeneous Graph Convolutional Networks

With the development of deep learning and other technologies, the research of information propagation prediction has also achieved important research achievements. However, the existing information diffusion studies either focus on the attention relationships of users or they predict the information according to the diffusion relationships of users, which makes the prediction results have certain limitations. Therefore, a prediction model has been proposed spatial–temporal attention heterogeneous graph convolutional networks (STAHGCNs). First, we use GCN to learn user influence relationships and user behavior relationships, and we propose a user representation fusion mechanism to learn the user characteristics. Second, to account for the dynamics of user behavior, a temporal attention mechanism strategy is used to encode time into the heterogeneous graph to obtain a more expressive user representation. Finally, the obtained user representation is input into the multihead attention mechanism for information propagation prediction. Experimental results performed on the Twitter, Douban, Digg, and Memetracker datasets have shown that the proposed STAHGCN model increased by 8.80% and 6.74% at hits@N and map@N, respectively, which are significantly better than the original latest DyHGCN model. The proposed STAHGCN model effectively integrates spatial factors, such as time factor, user influence, and behavior, which greatly improves the accuracy of information propagation prediction and has great significance for rumor monitoring and malicious account detection.

Behavior of solutions to semilinear evolution inequalities in an annulus: The critical cases

In the present paper, we consider the parabolic and hyperbolic inequalities with singular potentials and with critical nonlinearities in the annulus domain. The problems are studied with Neumann-type and Dirichlet-type boundary conditions on the boundary. Moreover, we study the systems of problems too. We have proved that the above problems are globally unsolvable in critical cases, thereby filling the gaps the recent results by Jleli and Samet in [J. Math. Anal. Appl. 514: 2 (2022)] and in [Anal. Math. Phys. 12: 90 (2022)]. Proofs are carried out using the method of test functions with logarithmic arguments, which is being developed for the first time in bounded domains.

Association between accelerometry measured patterns of sedentary behaviors and functional status in older adults

BackgroundOlder adults are highly sedentary, and too much sedentary behavior (SB) is associated with negative health effects, but little is known about SB patterns and their associations with functional status.AimsTo examine the association between objectively measured sedentary behavior time (SBT) and sedentary behavior fragmentation (SBF) and functional status in older adults using the National Health Aging Trends Study (NHATS) dataset, a nationally representative sample from 2021.MethodsData from NHATS were analyzed using weighted linear regressions to examine the association between objective measures of SBT (mean hours spent in SB/day during waking hours) and SBF, and six functional variables (difficulties with activities of daily living [ADL], short physical performance battery, hand grip strength, immediate word recall, delayed word recall, and mental health), accounting for sociodemographic, body mass index, and the number of chronic conditions.ResultsA total of 738 individuals from the NHATS were included. Higher SBT was associated with greater difficulties with ADL, poorer short physical performance battery and hand grip strength, lower scores in both immediate and delayed word recall, and poorer mental health. Higher SBF was associated with fewer difficulties with ADL, better short physical performance battery and hand grip strength, a higher score in immediate word recall, and better mental health.Discussionand conclusionsGreater fragmentation of SB was associated with better function, and increasing SBF may be a useful strategy for mitigating the effects of SB in older adults, but prospective research is needed to support this approach.

Brownian Particle in the Curl of 2-D Stochastic Heat Equations

We study the long time behaviour of a Brownian particle evolving in a dynamic random environment. Recently, Cannizzaro et al. (Ann Probab 50(6):2475–2498, 2022) proved sharp log\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sqrt{\\log }$$\\end{document}-super diffusive bounds for a Brownian particle in the curl of (a regularisation of) the 2-D Gaussian Free Field (GFF) ω̲\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\underline{\\omega }$$\\end{document}. We consider a one parameter family of Markovian and Gaussian dynamic environments which are reversible with respect to the law of ω̲\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\underline{\\omega }$$\\end{document}. Adapting their method, we show that if s≥1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$s\\ge 1$$\\end{document}, with s=1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$s=1$$\\end{document} corresponding to the standard stochastic heat equation, then the particle stays log\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sqrt{\\log }$$\\end{document}-super diffusive, whereas if s<1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$s<1$$\\end{document}, corresponding to a fractional heat equation, then the particle becomes diffusive. In fact, for s<1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$s<1$$\\end{document}, we show that this is a particular case of Komorowski and Olla (J Funct Anal 197(1):179–211, 2003), which yields an invariance principle through a Sector Condition result. Our main results agree with the Alder–Wainwright scaling argument (see Alder and Wainwright in Phys Rev Lett 18:988–990, 1967; Alder and Wainwright in Phys Rev A 1:18–21, 1970; Alder et al. in Phys Rev A 4:233–237, 1971; Forster et al. in Phys Rev A 16:732–749, 1977) used originally in Tóth and Valkó (J Stat Phys 147(1):113–131, 2012) to predict the log\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\log $$\\end{document}-corrections to diffusivity. We also provide examples which display loga\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\log ^a$$\\end{document}-super diffusive behaviour for a∈(0,1/2]\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$a\\in (0,1/2]$$\\end{document}.

Detection and prediction of photovoltaic panels malfunctions

This article discusses issues of photovoltaic panels malfunctions and failures. Several computerized detection methods are applied on 300 real commercial crystalline Si photovoltaic installations to identify origin, quantity and time behaviour of most common malfunctions. This paper focuses only on operational failures while malfunctions derivable from fabrication process and transport are not in account. Failures influence on VA characteristic is deeply discussed. Possible usage of computerized real time VA characteristic measurements for backward failure detection and identification is evaluated. The main contribution of this research is the application and verification of this method on 8 channel pilot system.

Impact of stalling events on microcirculatory hemodynamics in the aged brain.

The role of cerebral microvasculature in cognitive dysfunction can be investigated by identifying the impact of blood flow on cortical tissue oxygenation. In this paper, the impact of capillary stalls on microcirculatory characteristics such as flow and hematocrit (Ht) in the cortical angioarchitecture is studied. Using a deterministic mathematical model to simulate blood flow in a realistic mouse cortex, hemodynamics parameters, including pressure, flow, vessel diameter-adjustable hematocrit, and transit time are calculated as a function of stalling events. Using a non-linear plasma skimming model, it is observed that Ht increases in the penetrating arteries from the pial vessels as a function of cortical depth. The incidence of stalling on Ht distribution along the blood network vessels shows reduction of RBCs around the tissue near occlusion sites and decreased Ht concentration downstream from the blockage points. Moreover, upstream of the occlusion, there is a noticeable increase of the Ht, leading to larger flow resistance due to higher blood viscosity. We predicted marked changes in transit time behavior due to stalls which match trends observed in mice invivo. These changes to blood cell quantity and quality may be implicated in the development of Alzheimer's disease and contribute to the course of the illness.

Large time behavior of weak solutions to d-dimensional micropolar Rayleigh-Bénard problem

This paper focuses on the large time behavior of the global weak solutions to the micropolar Rayleigh-Bénard problem near a hydrostatic equilibrium in Rd with d=2,3. We obtain the optimal decay rates (t+1)−d4(2q−1) and (t+1)−12−d4(2q−1) of the L2 norm of a solution and its first derivatives to this system with full dissipation, or with zero angular viscosity. Moreover, the enhanced decay rate (t+1)−12−d4(2q−1) of the L2 norm of the micro-rotational velocity is also established.

Random search processes on complex networks: From a static target to a moving object

We investigate the transition behavior of search time from visiting a static target to hunting a moving one on complex networks. This is achieved by introducing a relative moving speed ratio that quantifies how the time scale of a searcher differs from that of a mobile target. We adopt mean first encounter time to quantify the search time required to capture a time-moving target and derive its analytical expression. Remarkably, we find that with the increase of their relative speed ratio, the expected search time increases gradually and finally approaches that of visiting a static target. This interesting transition behavior keeps invariant even changing the associated navigation strategies of the searcher and the moving object. These findings are confirmed by numerical results on various synthetic and real networks. Our work, for the first time, reveals the increasing pattern of search time from a static target to a moving one on networks.

Association between screen time and physical activity on mental health among preschoolers: a cross-sectional study from Southwest China.

Screen time and physical activity behaviors undergo development during early childhood and impact mental health. However, there is limited knowledge regarding the associations between physical activity, screen time, and mental health problems (MHP) in preschoolers. This study examines these associations using a large sample size and brief measures. A multistage cluster stratified sampling method was used to conduct an observational cross-sectional study of 19,015 Chinese preschoolers in 2020. Information on physical activity, and screen time was collected by a self-administered questionnaire; MHP was assessed by the parent-reported Strengths and Difficulties Questionnaire (SDQ). Logistic regression models were used to obtain the odds ratios (ORs) and 95% confidence intervals (95% CIs) of preschoolers' MHP associated with screen time, total physical activities, moderate to vigorous physical activity (MVPA), and outdoor physical activities. A total of 19,015 participants from the 19,548 recruited population were included in the analyses (missing rate: 2.73%), 52.60% were boys. 64.01%, 57.96%, 35.98%, and 82.64% of preschoolers were reported to meet total physical activities, MVPA, and outdoor activities with screen time recommendations level. The results of multivariable-adjusted ORs (95% CIs) of preschoolers' MHP for comparisons of different levels of screen time (< 2h/day, 2-4h/day,≥4h/day) show that screen time positively associated with MHP after adjusting for confounders (P < 0.05), but the association was not significant among girls with screen time ≥ 4h/day. In addition, increased engagement in physical activity was reversely linked to MHP (P < 0.05). A stronger association between MHP and MVPA was observed in boys, however, this association was weakened when the total time spent engaging in MVPA exceeded two hours per day (P < 0.05). Less physical activity and more screen time positively relate to MHP, but the relationship differs by type of physical activity, total time, and gender. These findings provide novel insights and evidence supporting for guidelines on physical activity, screen time, and improvement of mental health for preschoolers.

Probing polypharmacy, ageing and sex effects on physical function using different tests.

Ageing, sex and polypharmacy affect physical function. This mouse study investigates how ageing, sex and polypharmacy interact and affect grip strength, balance beam and wire hang, correlating and comparing the different test results between and within subgroups. Young (2.5 months) and old (21.5months) C57BL/6J male and female mice (n =10-6/group) were assessed for physical function at baseline on grip strength, balance beam and wire hang with three trials of 60 s (WH60s) and one trial of 300 s (WH300s). Mice were randomised to control or diet containing a high Drug Burden Index (DBI, total anticholinergic and sedative drug exposure) polypharmacy regimen (metoprolol, simvastatin, citalopram, oxycodone and oxybutynin at therapeutic oral doses). Following 6-8weeks of treatment, mice were reassessed. High DBI polypharmacy and control mice both showed age group differences on all tests (p <0.05). Only control mice showed sex differences, with females outperforming males on the WH60s and balance beam for old mice, WH300s for young mice (p <0.05). Polypharmacy reduced grip strength in all subgroups (p <0.05) and only in old females reduced wire hang time and cumulative behaviour and balance beam time and %walked (p <0.05). Physical function assessments were all correlated with each other, with differences between subgroups (p <0.05), and mice within subgroups showed interindividual variability in performance. Age, sex and polypharmacy have variable effects on different tests, and behavioural measures are useful adjuvants to assessing performance. There was considerable within-group variability in change in measures over time. These findings can inform design and sample size of future studies.

Research and Application of FPGA Function Verification Methods

FPGA functional verification methods include simulation and timing simulation. Simulation and testing of digital circuits through mathematical models before physical implementation can help reduce development risks. Time series simulation focuses on evaluating the time behavior of FPGA design to ensure that the signal meets the timing requirements. Hardware Description Language (HDL) plays a crucial role in FPGA design, supporting design reuse and improving efficiency. The application areas include communication systems, image processing, automotive electronics, and industrial control systems. Verification requirements include temporal consistency, real-time response, and adaptability.

Effects of driving style on takeover performance during automated driving: Under the influence of warning system factors

Driving style has been proposed to be a critical factor in automated driving. However, the role of driving style in the process of taking over during automated driving needs further investigation. The main purpose of this study was to investigate the influence of driving style on takeover performance under the influence of warning system factors. In addition, this study also explored whether the impact of driving style on reaction time varies over time and the role of driving style on a comprehensive takeover quality indicator. Two driving simulation experiments with different takeover request (TOR) designs were conducted. In experiment 1, content warning information was provided in the TOR with different warning stage designs; in experiment 2, countdown warning information was provided in the TOR with different warning stage designs. Sixty-four participants (32 for experiment 1 and 32 for experiment 2) were classified into two groups based on their driving style (i.e., aggressive, or defensive) using the Chinese version of the Multidimensional Driving Style Inventory (the brief MDSI-C). The results suggested that drivers’ driving style had significant effects on takeover performance, but the effects were influenced by warning system designs. Specifically, defensive participants performed better takeover performance, i.e., shorter reaction time and cautious vehicle control behaviors, than aggressive participants in most warning conditions. The content and countdown warning information and warning stage design affected the roles of driving style on takeover performance: 1) compared to the one-stage warning design, the two-stage warning design significantly shortened the reaction time of the participants with different driving styles, 2) compared to the countdown warning information design, the design of content warning information can shorten the reaction time of aggressive participants and lengthen the reaction time of defensive participants in the two-stage warning conditions, and 3) compared to the content warning information design, countdown warning information can improve the safe takeover performance of defensive participants. This study provides a better understanding of the role of driving style on takeover performance, and driving style should be considered when designing warning systems for autonomous vehicles.

Timing theory integrated nursing combined behavior change integrated theory of nursing on primiparous influence.

The comprehension and utilization of timing theory and behavior change can offer a more extensive and individualized provision of support and treatment alternatives for primipara. This has the potential to enhance the psychological well-being and overall quality of life for primipara, while also furnishing healthcare providers with efficacious interventions to tackle the psychological and physiological obstacles encountered during the stages of pregnancy and postpartum. To explore the effect of timing theory combined with behavior change on self-efficacy, negative emotions and quality of life in patients with primipara. A total of 80 primipara cases were selected and admitted to our hospital between August 2020 and May 2022. These cases were divided into two groups, namely the observation group and the control group, with 40 cases in each group. The nursing interventions differed between the two groups, with the control group receiving routine nursing and the observation group receiving integrated nursing based on the timing theory and behavior change. The study aimed to compare the pre- and post-nursing scores of Chinese Perceived Stress Scale (CPSS), Edinburgh Postpartum Depression Scale (EPDS), Self-rating Anxiety Scale (SAS), breast milk knowledge, self-efficacy, and SF-36 quality of life in both groups. After nursing, the CPSS, EPDS, and SAS scores of the two groups was significantly lower than that before nursing, and the CPSS, EPDS, and SAS scores of the observation group was significantly lower than that of the control group (P = 0.002, P = 0.011, and P = 0.001 respectively). After nursing, the breastfeeding knowledge mastery, self-efficacy, and SF-36 quality of life scores was significantly higher than that before nursing, and the breastfeeding knowledge mastery (P = 0.013), self-efficacy (P = 0.008), and SF-36 quality of life (P = 0.011) scores of the observation group was significantly higher than that of the control group. The integration of timing theory and behavior change integrated theory has been found to be an effective approach in alleviating negative mood and stress experienced by primipara individuals, while also enhancing their self-efficacy and overall quality of life. This study focuses on the key concepts of timing theory, behavior change, primipara individuals, negative mood, and quality of life.

The effect of in-flume habituation time and fish behaviour on estimated swimming performance

Swimming performance is important for fish migration, habitat selection, and predator-prey interaction, as well as for fish passage design. Procedural choices made when experimentally estimating it may influence the results. Systematic experiments were conducted to study the effect of different in-flume habituation times, habituation behaviour, and the use of external encouragement on burst swimming performance of Rutilus aula, a small-sized cyprinid, in a fixed velocity testing protocol. Increasing habituation times from 30 s to 5 or 20 min substantially increased the success proportion of swimming trials and estimated fish swimming performance, with no difference between the latter two habituation times. Fish resting on the downstream grid before the start of testing velocity outperformed those who swam during habituation and transition periods. Fish swimming volitionally in response to flow at testing velocity showed a significantly improved performance compared to fish motivated by external poking. The results of this study highlight that in-flume habituation time is important, and fish behaviour before actual testing may influence the outcomes of swimming performance results.