Time Behavior Research Articles

Metabolic profiling of Qi-Yu-San-Long decoction in rat feces by ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry combined with a post-targeted screening strategy.

Research into traditional Chinese medicine metabolism in feces is one of the key avenues to understanding the fate of traditional Chinese medicines in vivo. In this study, we used ultraperformance liquid chromatography-quadrupole time-of-flight MS in combination with a post-targeted screening strategy to identify the prototype components and metabolites in rat feces after oral administration. Based on our group's previous research, the component database of Qi-Yu-San-Long decoction (QYSLD) was established. Prototype components were screened from the fecal samples based on summarized chromatographic and MS behaviors. According to the chemical structure characteristics of related compounds, the possible metabolic pathways were inferred, and the metabolites related to QYSLD were predicted. We extracted ion chromatograms by predicting the m/z values of metabolite excimer ions and identified related metabolites based on their retention time and fragmentation behavior. A total of 93 QYSLD-related xenobiotics were confirmed or tentatively identified in rat fecal samples, and the results indicated that the main metabolic pathways of QYSLD were hydrolysis, deglycosylation, oxidation, reduction, decarboxylation, methylation and acetylation. This study presents a rapid method for identifying the prototype components and metabolites, and offers valuable insights into the biotransformation profiling of QYSLD in rat feces.

Infant embodied attention in context: Feasibility of home-based head-mounted eye tracking in early infancy

Social communication emerges from dynamic, embodied social interactions during which infants coordinate attention to caregivers and objects. Yet many studies of infant attention are constrained to a laboratory setting, neglecting how attention is nested within social contexts where caregivers dynamically scaffold infant behavior in real time. This study evaluates the feasibility and acceptability of the novel use of head-mounted eye tracking (HMET) in the home with N = 40 infants aged 4 and 8 months who are typically developing and at an elevated genetic liability for autism spectrum disorder (ASD). Results suggest that HMET with young infants with limited independent motor abilities and at an elevated likelihood for atypical development is highly feasible and deemed acceptable by caregivers. Feasibility and acceptability did not differ by age or ASD likelihood. Data quality was also acceptable, albeit with younger infants showing slightly lower accuracy, allowing for preliminary analysis of developmental trends in infant gaze behavior. This study provides new evidence for the feasibility of using in-home HMET with young infants during a critical developmental period when more complex interactions with the environment and social partners are emerging. Future research can apply this technology to illuminate atypical developmental trajectories of embodied social attention in infancy.

The vanishing relaxation time behavior of multi-term nonlocal Jordan–Moore–Gibson–Thompson equations

The family of Jordan–Moore–Gibson–Thompson (JMGT) equations arises in nonlinear acoustics when a relaxed version of the heat flux law is employed within the system of governing equations of sound motion. Motivated by the propagation of sound waves in complex media with anomalous diffusion, we consider here a generalized class of such equations involving two (weakly) singular memory kernels in the principal and non-leading terms. To relate them to the second-order wave equations, we investigate their vanishing relaxation time behavior. The key component of this singular limit analysis are the uniform bounds for the solutions of these nonlinear equations of fractional type with respect to the relaxation time. Their availability turns out to depend not only on the regularity and coercivity properties of the two kernels, but also on their behavior relative to each other and the type of nonlinearity present in the equations.

Dispersive estimates for the wave equation inside cylindrical convex domains

The dispersive and Strichartz estimates are essential for establishing well posedness results for nonlinear equations as well as long time behaviour of solutions to the equation. While in the boundary-less case these estimates are well understood, the case of boundary the situation can become much more difficult. In this work, we establish local in time dispersive estimates for solutions of the model case Dirichlet wave equation inside cylindrical convex domains \(\Omega\subset\mathbb{R}^3\) with smooth boundary \(\partial\Omega\neq \emptyset\). In this paper, we provide detailed proofs of the results established in [16, 17]. Let us recall that dispersive estimates are key ingredients to prove Strichartz estimates. Strichartz estimates for waves inside an arbitrary domain \(\Omega\) have been proved by Blair, Smith, Sogge [4, 5]. Optimal estimates in strictly convex domains have been obtained in [12]. Our case of cylindrical domains is an extension of the result of [12] in the case when the nonnegative curvature radius depends on the incident angle and vanishes in some directions.

Restaurant worker food safety and sanitation compliance behavior in times of crisis: an investigation of transactional leadership behavior effectiveness

ABSTRACT This study investigated the use of the transactional leadership style (TLB) by restaurant managers and its effect on food safety compliance by restaurant employees in the United States. Utilizing parallel mediation analyses, the study investigated the impact that fear, responsibility, knowledge, and gain had on compliance. Results provide theoretical and practical implications related to the effective use of TLB in motivating compliance amongst employees. The importance of implementing disciplinary actions for noncompliance is suggested and results indicate that compliance was more likely when employees felt a sense of responsibility, understood food safety rules, and believed they would experience gain.

Context-specific and context-invariant computations of interval timing.

An accurate sense of time is crucial in flexible sensorimotor control and other cognitive functions. However, it remains unknown how multiple timing computations in different contexts interact to shape our behavior. We asked 41 healthy human subjects to perform timing tasks that differed in the sensorimotor domain (sensory timing vs. motor timing) and effector (hand vs. saccadic eye movement). To understand how these different behavioral contexts contribute to timing behavior, we applied a three-stage Bayesian model to behavioral data. Our results demonstrate that the Bayesian model for each effector could not describe bias in the other effector. Similarly, in each task the model-predicted data could not describe bias in the other task. These findings suggest that the measurement stage of interval timing is context-specific in the sensorimotor and effector domains. We also showed that temporal precision is context-invariant in the effector domain, unlike temporal accuracy. This combination of context-specific and context-invariant computations across sensorimotor and effector domains suggests overlapping and distributed computations as the underlying mechanism of timing in different contexts.

The Hardy inequality and large time behaviour of the heat equation on [formula omitted

In this paper we study the large time asymptotic behaviour of the heat equation with Hardy inverse-square potential on corner spaces RN−k×(0,∞)k, k≥0. We first show a new improved Hardy-Poincaré inequality for the quantum harmonic oscillator with Hardy potential. In view of that, we construct the appropriate functional setting in order to pose the Cauchy problem. Then we obtain optimal polynomial large time decay rates and subsequently the first term in the asymptotic expansion of the solutions in L2(RN−k×(0,∞)k). Particularly, we extend and improve the results obtained by Vázquez and Zuazua (J. Funct. Anal. 2000), which correspond to the case k=0, to any k≥0. We emphasize that the higher the value of k the better time decay rates are. We employ a different and simplified approach than Vázquez and Zuazua, managing to remove the usage of spherical harmonics decomposition in our analysis.

Surface Characterization and Tribology Behavior of PMMA Processed by Excimer Laser

Polyoxymethylene methacrylate (PMMA) is widely used in ophthalmic biomaterials. Misuse of PMMA in extreme environments is likely to damage the ocular surface and intraocular structures. The surface characterization and tribological behavior of PMMA processed using an excimer laser were investigated in this study by contrasting different lubrication conditions and friction cycles. The results show that the roughness of the material surface increases with laser processing, which changes its physical structure. Under lubrication, the laser-treated PMMA exhibits better hydrophilicity, especially during the use of eye drops. No obvious relationship exists between the laser-processing time and friction behavior. However, the laser treatment may contribute to the formation of friction and wear mechanisms of PMMA materials. Laser-treated PMMA in saline solution exhibits better abrasive resistance by showing a lower wear rate than that in eye drops, although it has a higher friction coefficient. In this study, the different friction stages in laser-treated PMMA were clarified under two lubrication conditions. The wear rates of the laser-treated PMMA were found to decrease with the number of cycles, and the friction coefficient has a similar variation tendency. The wear behavior of the laser-treated PMMA is dominated by the main abrasive wear and secondary transferred film formation. This study provides a theoretical basis for the development and application of ophthalmic biomaterials in complex environments by examining the material surface interface behavior and wear mechanism after laser processing using PMMA as the research matrix.

Asymptotic profile for the interaction of a rigid ball and an incompressible viscous fluid

In this paper, we study the large time behavior of the solutions of the Stokes fluid-solid system. We compute the asymptotic expansion of the solution for Lq integrable initial data U0. We show that the asymptotic profile of the solution is a linear combination of the Stokes fundamental solution for the data with extra condition |x|U0∈L1. We also show that L1 integrability of the solution is strongly related to the net force exerted by the fluid on the boundary of the solid.

Squeak and rattle noise prediction in vehicle acoustics

AbstractSqueak and rattle belong to unintended noise audible by occupants of a vehicle. This noise negatively affects the perceived built quality, leading to nonbuying decisions, high warranty costs, and poor brand reputation. Therefore, vehicle manufacturers seek to prevent the emergence of such noise, preferably in the early development phase and during production at the latest. This causes substantial monetary and temporal expenditure, which must be minimized. Rattle is defined as repeated impact. The underlying physical phenomenon is impulsive short‐duration contact normal to the surface. Squeak, in contrast, originates from an in‐contact motion in the tangential direction and is a friction‐induced stick‐slip phenomenon. State‐of‐the‐art numerical squeak and rattle prediction is based on linear analysis resulting in an empirical noise risk index. However, quantification of noise and assessment of audibility is not possible. The reason is the nonlinearity of the contact forces. Hence, the actual system response is not calculable with a linear approach. Mathematically, the nature of both excitation events is nonlinear due to frictional contact and nonsmooth due to short impulsive behavior in time. This makes linear simplification and a solution process in the time domain challenging. Both events appear periodically, leading to an oscillation characterized by fundamental and higher harmonics. Due to this periodic character, squeak and rattle phenomena fulfill the prerequisite for applying the harmonic balance method (HBM) to solve the governing nonlinear equation of motion. The more harmonics considered, the more precise the modeling and the dynamic response prediction. In addition, the alternating frequency/time domain method (AFT) allows for switching between the frequency and the time domain during the iterative solution process. Thus, the nonlinear contact forces can be evaluated in the time domain. The equation‐solving process results in the calculation of surface velocities. This gives way to determining a proxy for the emitted sound power of the oscillatory system. The simulation method based on combining HBM and AFT was validated on test rigs for squeak and rattle noise. The industrial applicability of this simulation approach was demonstrated numerically and experimentally on an actual vehicle part showing promising results. Thereby, important steps in nonlinear structural dynamics and vehicle acoustics were made toward a calm, smooth, and enjoyable ride for vehicle occupants.

Analysis of Factors Affecting the Extra Journey Time of Public Bicycles

Many countries worldwide are introducing public bicycle systems to reduce urban traffic and environmental problems. However, studies on the usage behavior of public bicycles have not considered the trip purpose of riders extensively due to data limitations. Therefore, this study defined the “extra journey time” from usage time and origin–destination (OD) expected time and clustered public bicycle usage behaviors. Subsequently, the effects of the location characteristics of the departure and arrival stations, road environmental factors, and weather conditions for each cluster were analyzed. Three clusters were obtained from the results. Riders in Cluster 1 were inferred to have used the bicycles to commute and for work purposes, and riders in Clusters 2 and 3 used the bicycles for leisure purposes. Moreover, the bike station location characteristics, road environmental factors, and weather conditions influenced the probability of classification into one cluster. In particular, bike lanes near the departure and arrival stations increased the probability of classification under Clusters 2 and 3. The trip patterns according to the extra journey time of public bicycles were classified under these clusters. Furthermore, the differences in the characteristics of the bicycle usage types were identified according to the location and meteorological factors affecting them.

Effects of empathy and egoism on CSR perceptions and consumer buycotts: Lessons learned during global crisis in support of equitable business practices

ABSTRACT Consumer polarization leading to buycotts and boycotts was magnified by the global crisis of 2020–2021 which changed consumer priorities and business practices: in-person shopping decreased, while social distancing, remote work, and media consumption increased. In this context, we examined the relationships among egoism, empathy, and consumer interest in social topics. These topics included employee treatment, social justice, and the environment. We highlighted aligning Corporate Social Responsibility (CSR) efforts with consumer values. Using a survey method and structural equation modeling, we found such efforts increased consumer buycott. In this research we addressed whether consumers were motivated by empathy or egoism to engage in buycotting during global crisis. Consumers reacted to a firm’s adherence to health and safety guidelines, respect for human rights, and engaged in environmental protection. This study contributes to the literature on CSR and prosocial behavior. It examined the relationships among key consumer characteristics and corporate behavior in times of crisis and expands the existing literature on psychological factors that play a role in buycotting. The findings are applicable to policy makers, academic literature, and practice as it offers practical recommendations on how companies might consider realignment of CSR activities during crisis. It also suggests directions for future research.

Universal dynamics and non-thermal fixed points in quantum fluids far from equilibrium

AbstractClosed quantum systems far from thermal equilibrium can show universal dynamics near attractor solutions, known as non-thermal fixed points, generically in the form of scaling behaviour in space and time. A systematic classification and comprehensive understanding of such scaling solutions are tasks of future developments in non-equilibrium quantum many-body theory. In this tutorial review, we outline several analytical approaches to non-thermal fixed points and summarise corresponding numerical and experimental results. The analytic methods include a non-perturbative kinetic theory derived within the two-particle irreducible effective action formalism, as well as a low-energy effective field theory framework. As one of the driving forces of this research field are numerical simulations, we summarise the main results of exemplary cases of universal dynamics in ultracold Bose gases. This encompasses quantum vortex ensembles in turbulent superfluids as well as recently observed real-time instanton solutions in one-dimensional spinor condensates.

Fast and inexpensive emission-time in-situ setup for upconversion nanoparticle characterization

In this work, a straightforward analytical approach is presented for the evaluation of the entire time-resolved emission spectrum of Er3+-doped upconversion nanoparticles (UCNP) by the acquisition of bidimensional emission wavelength-time signals. Employing diffractive optics and fast optomechanical sweeping, the entire emission wavelength-time matrix (EtM) of UCNP is registered. An optic fibre probe allows the measurement of micrometric-size domains in surfaces, either in solid form or in suspension. Further chemometric analysis was also performed to gain further insight into the behaviour of the emission bands and their corresponding time curve profiles. To show the applicability of the developed procedure, changes either in the emission spectrum or the time behaviour by external perturbations were monitored and EtM at different temperatures was acquired as a proof of concept. The results demonstrated the effectiveness of the proposed procedure in obtaining fast and highly informative images and enlightening knowledge about the phosphorescence-based system.

Incremental Online Machine Learning for Detecting Malicious Nodes in Vehicular Communications Using Real-Time Monitoring

Detecting malicious activities in Vehicular Ad hoc Networks (VANETs) is an important research field as it can prevent serious damage within the network and enhance security and privacy. In this regard, a number of approaches based on machine learning (ML) algorithms have been proposed. However, they encounter several challenges due to data being constantly generated over time; this can impact the performance of models trained on fixed datasets as well as cause the need for real-time data analysis to obtain timely responses to potential threats in the network. Therefore, it is crucial for machine learning models to learn and improve their predictions or decisions in real time as new data become available. In this paper, we propose a new approach for attack detection in VANETs based on incremental online machine learning. This approach uses data collected from the monitoring of the VANET nodes’ behavior in real time and trains an online model using incremental online learning algorithms. More specifically, this research addresses the detection of black hole attacks that pose a significant threat to the Ad hoc On Demand Distance Vector (AODV) routing protocol. The data used for attack detection are gathered from simulating realistic VANET scenarios using the well-known simulators Simulation of Urban Mobility (SUMO) and Network Simulator (NS-3). Further, key features which are relevant in capturing the behavior of VANET nodes under black hole attack are monitored over time. The performance of two online incremental classifiers, Adaptive Random Forest (ARF) and K-Nearest Neighbors (KNN), are assessed in terms of Accuracy, Recall, Precision, and F1-score metrics, as well as training and testing time. The results show that ARF can be successfully applied to classify and detect black hole nodes in VANETs. ARF outperformed KNN in all performance measures but required more time to train and test compared to KNN. Our findings indicate that incremental online learning, which enables continuous and real-time learning, can be a potential method for identifying attacks in VANETs.

Effect of triethanolamine on the initial setting time and hydration behavior of BOFS - cement materials

Triethanolamine (TEA) has been widely used as the chemical admixture to modify the workability of cement-based materials. In order to investigate the effect of triethanolamine (TEA) dosages on the setting time and hydration performance of steel slag-cement composites materials (SSCMs), different dosages of TEA are used to prepare cementitious composites. A range of trials, including microstructural analysis of hydration products, initial setting time, isothermal conduction calorimetry, thermogravimetric analysis and thermodynamic modelling (GEMS) are carried out to investigate the setting time and hydration properties of SSCMs. The results showed that the hydration products of C12A7 phase in steel slag overlapped each other by adding high dosage of TEA (0.5%) and could build a good solidification network. Improving TEA dosages could stimulate the aluminates phase, which could shorten the initial setting time in hydration process. When the amount of triethanolamine increasing to 0.5%, the degree of SSCMs hydration is enhanced substantially. Furthermore, thermodynamic modelling calculations show that with the C12A7 content increases, more C3AH6 and AFm are formed rather than ettringite. These results may contribute to improving the utilization of steel slag and the construction efficiency.

Association between maternal pre-pregnancy body mass index and offspring’s outcomes at 9 to 15 years of age

ObjectiveMaternal pre-pregnancy underweight, overweight and obesity might increase the risk for worse short- and long-term outcome in the offspring. There is a need for further study into the relationship between maternal pre-pregnancy body mass index (BMI) and the combined outcome of physical development, state of health and social behavior in children. Question: Is maternal pre-pregnancy BMI associated with the child outcome in terms of physical development, state of health and social behavior (school and leisure time behavior) at the age of 9 to 15 years?MethodsIn the population-based birth cohort study Survey of Neonates in Pomerania (SNIP) children at the age 9–15 years and their families were re-examined by questionnaire-based follow-up. 5725 mother–child pairs were invited to SNiP-follow-up. This analysis is based on the recall fraction of 24.1% (n = 1379). Based on the maternal pre-pregnancy BMI (ppBMI), 4 groups were formed: underweight (ppBMI < 19 kg/m2, n = 117), normal weight (ppBMI 19–24.99 kg/m2, n = 913, reference), overweight (ppBMI 25–30 kg). /m2, n = 237) and obesity (ppBMI > 30 kg/m2, n = 109).ResultsIn the multiple regression model, the BMI-z-score for children of mothers in the underweight group was −0.50 lower, and 0.50/1.07 higher in the overweight/obese group (p < 0.001) compared to reference at median age of 12 years. No differences were found in children of underweight mothers with regard to social behavior (interaction with friends and family), school and sports performance (coded from “very good” to “poor”), other leisure activities (watching television, using mobile phones, gaming), and health (occurrence of illnesses) compared to children of normal weight mothers. In contrast, maternal pre-pregnancy overweight and obesity were associated with lower school and sports performance, and higher screen time (smart phone, gaming, television) compared to children of normal weight mothers.ConclusionMaternal pre-pregnancy overweight and obesity but not underweight was negatively associated with school performance and leisure time behavior in the offspring at 9–15 years of age.

Synergistic Verification of Hardware Peripherals through Virtual Prototype Aided Cross-Level Methodology Leveraging Coverage-Guided Fuzzing and Co-Simulation

In this paper, we propose a Virtual Prototype (VP) driven verification methodology for Hardware (HW) peripherals. In particular, we combine two approaches that complement each other and use the VP as a readily available reference model: We use (A) Coverage-Guided Fuzzing (CGF) which enables comprehensive verification at the unit-level of the Register-Transfer Level (RTL) HW peripheral with a Transaction Level Modeling (TLM) reference, and (B) an application-driven co-simulation-based approach that enables verification of the HW peripheral at the system-level. As a case-study, we utilize a RISC-V Platform Level Interrupt Controller (PLIC) as HW peripheral and use an abstract TLM PLIC implementation from the open source RISC-V VP as the reference model. In our experiments we find three behavioral mismatches and discuss the observation of these, as well as non-functional timing behavior mismatches, that were found through the proposed synergistic approach. Furthermore, we provide a discussion and considerations on the RTL/TLM Transactors, as they embody one keystone in cross-level methods. As the different approaches uncover different mismatches in our case-study (e.g., behavioral mismatches and timing mismatches), we conclude a synergy between the methods to aid in verification efforts.

Contract-based specification of mode-dependent timing behavior

The design of safety-critical systems calls for rigorous application of specification and verification methods. In this context, a comprehensive consideration of safety aspects, which inevitably include timing properties, requires explicit addressing of operating modes and their transitions in the system model as well as in the respective specifications. As a side effect, this helps to reduce verification complexity. This paper presents an extension of a framework for the specification of timing properties following the contract-based design paradigm. It provides enhancements of the underlying specification language, which enables specifying modes, mode transitions, and mode-dependent behavior. A formal semantics is given in order to enable reasoning about such specifications as well as about contract operations like refinement and composition, thus enabling to make statements about mode composition. The results are discussed using a real-world example.

Experimental investigation of the effect of functionalized graphene on the creep behavior of epoxy

The objective of the current work was to investigate the creep behavior of functionalized graphene (f-GNF)-epoxy nanocomposite. Time and temperature-dependent mechanical behaviors were investigated by performing creep tests at three different stress levels and two different temperatures. Graphene produced by the electric arc discharge method was functionalized with Triton X-100 by a non-covalent method. Then, f-GNF-epoxy nanocomposites are produced by using the Three Roll Milling (3RM) method to eliminate nanofiller agglomeration. By performing quasi-static compression tests, stress levels for creep tests are determined as 50, 100, and 200 MPa to guarantee the viscoelastic deformation regime, around yield, and the viscoplastic deformation regime, respectively. The results indicate significant creep resistance in the nanocomposite with 0.1 wt% f-GNF. Depending on temperature and stress level, the effect of f-GNF is more pronounced at higher stresses and temperatures. f-GNFs have a significant effect on inhibiting the mobility of polymer chains, resulting improvements in the creep modulus. This indicates that thermally activated processes controlling the creep rate are in part inhibited by the presence of f-GNF. In the creep tests carried out for 2 h, a maximum improvement of 85% was observed in the creep modulus of epoxy-nanocomposite compared to pure epoxy at room temperature.