Time Behavior Research Articles

Understanding customer experience over time and customer citizenship behavior in retail environment: The mediating role of customer brand relationship strength

Understanding customer experience over time and customer citizenship behavior in retail environment: The mediating role of customer brand relationship strength

Transient behavior of a molten salt fast reactor under two-phase flow conditions with helium bubbling

In the present study, transient behaviors of a chloride molten salt fast reactor without control rods under two-phase flow conditions are analyzed assuming a bypass of the safety protection system. The two-phase flow in the core is caused by helium bubbles injected to remove the gases of the fission product. The void fraction under the rated condition is assumed to be as low as 0.2 %. However, as the fuel flow rate decreases, the void fraction increases inversely proportional to the flow rate and must be considered in any transient analysis. Therefore, analyses with a point reactor kinetics and thermal-hydraulics coupling model have been performed to account for void flow using the CFD code. Comparison between the transient under two-phase flow and the transient under single-phase flow in which the effect of reactivity due to voids is taken into account with the CFD analysis, shows almost the same results, although there are slight differences due to the difference in fuel volume corresponding to the void fraction. When analyzing transients with a system code that has difficulty handling two-component two-phase flow, the void effect has been considered using the above-mentioned single-phase flow analysis. In this way, the entire plant is analyzed using the RELAP5-3D code and the core inlet conditions are passed to the FLUENT code to analyze the transient behavior. The transients analyzed are UTOP, USBO, ULOFF, and ULOHS under the assumption of bypassing the safety protection system. In addition, a transient assuming the loss of helium bubble supply under the decay heat power conditions is analyzed and discussed. The results of the analysis are compared with the results of the same event without voids analyzed using RELAP5-3D. In the case of single-phase flow, the reactor power changes mainly due to temperature feedback. Although the two types of transients have similar appearance, the breakdown of reactivity is quite different. Relating the comparison between the calculated result using the system code and CFD code shows that for the short time behavior until the fuel flow rate shifts to low flow rate, the results of the CFD code, which can analyze the behavior of the helium voids, are more appropriate. However, there are no major problems in the same transient calculation using RELAP5-3D, which calculates the entire plant system.

Single-Molecule Graphene Liquid Cell Electron Microscopy for Instability of Intermediate Amyloid Fibrils.

Single-molecule techniques are powerful microscopy methods that provide new insights into biological processes. Liquid-phase transmission electron microscopy (LP-TEM) is an ideal single-molecule technique for overcoming the poor spatiotemporal resolution of optical approaches. However, single-molecule LP-TEM is limited by several challenges such as electron-beam-induced molecular damage, difficulty in identifying biomolecular species, and a lack of analytical approaches for conformational dynamics. Herein, a single-molecule graphene liquid-cell TEM (GLC-TEM) technique that enables the investigation of real-time structural perturbations of intact amyloid fibrils is presented. It is demonstrated that graphene membranes significantly extend the observation period of native amyloid beta proteins without causing oxidative damage owing to electron beams, which is necessary for imaging. Stochastic and time-resolved investigations of single fibrils reveal that structural perturbations in the early fibrillar stage are responsible for the formation of various amyloid polymorphs. The advantage of observing structural behavior in real time with unprecedented resolution will potentially make GLC-TEM a complementary approach to other single-molecule techniques.

Local time of a system of Brownian particles on the line with steplike initial condition.

We consider a system of noninteracting Brownian particles on a line with a steplike initial condition, and we investigate the behavior of the local time at the origin at large times. We compute the mean and the variance of the local time, and we show that the memory effects are governed by the Fano factor associated with the initial condition. For the uniform initial condition, we show that the probability distribution of the local time admits a large deviation form, and we compute the corresponding large deviation functions for the annealed and quenched averaging schemes. The two resulting large deviation functions are very different. Our analytical results are supported by extensive numerical simulations.

Consumptive Behavior: Are Financial Literacy, Electronic Money, Lifestyle, and Self-Control Necessary?

Aims: Consumptive behavior has become familiar to students because of the support of an increasingly modern era and the ease of buying needs or wants. This study aims to determine whether financial Literacy, electronic Money, Lifestyle, and self-control significantly affect consumer behavior, especially among students. Study Design: Active FEB students in DKI Jakarta Province, Central Java, Special Region of Yogyakarta Place and Duration of Study: at Universitas Negeri Jakarta, Universitas Muhammadiyah Purwokerto, Universitas Wijayakusuma Purwokerto, Universitas Diponegoro, Universitas Tidar, Universitas Gajah Mada and Universitas UPN Yogyakarta, which have a total of 18.255 students. The sample for this study is 160 respondents that was determined using the Slovin technique. Methodology: In this research, the methods used to analyze data are using a Partial Least Square (PLS) based structural equation model (SEM). By using SmartPLS 3.0, each hypothesis will be tested to understand the relationships between variables. To test Validity and reliability, the research uses an outer model. Hypothesis testing was done using inner models. Results: Financial Literacy had no significant effect on consumptive behavior. Electronic 0money has no significant impact on consumptive behavior. Lifestyle significantly affects consumptive behavior with Original Sample 0,449. Self-control significantly affects consumptive behavior with Original Sample 0,187. Conclusion: Financial Literacy and electronic Money do not ultimately influence students' consumptive behavior; this could happen because students do not use their financial understanding in everyday life, and the ease of electronic money does not affect students' consumptive behavior. At the same time, Lifestyle and self-control influence student consumption behavior. Uncontrolled Lifestyle and self-control make students consumptive in everyday life.

Driver Distraction Detection Based on Cloud Computing Architecture and Lightweight Neural Network

Distracted behavior detection is an important task in computer-assisted driving. Although deep learning has made significant progress in this area, it is still difficult to meet the requirements of the real-time analysis and processing of massive data by relying solely on local computing power. To overcome these problems, this paper proposes a driving distraction detection method based on cloud–fog computing architecture, which introduces scalable modules and a model-driven optimization based on greedy pruning. Specifically, the proposed method makes full use of cloud–fog computing to process complex driving scene data, solves the problem of local computing resource limitations, and achieves the goal of detecting distracted driving behavior in real time. In terms of feature extraction, scalable modules are used to adapt to different levels of feature extraction to effectively capture the diversity of driving behaviors. Additionally, in order to improve the performance of the model, a model-driven optimization method based on greedy pruning is introduced to optimize the model structure to obtain a lighter and more efficient model. Through verification experiments on multiple driving scene datasets such as LDDB and Statefarm, the effectiveness of the proposed driving distraction detection method is proved.

Will commodity futures reduce systemic risk in the spot market? Evidence from Chinese commodity market

PurposeThis paper aims to investigate whether the establishment of commodity futures can effectively hedge systemic risk in the spot network, given the context of financialization in the commodity futures market.Design/methodology/approachUtilizing industry association data from the Chinese commodity market, the authors identify systemically important commodities based on their importance in the production process using multiple graph analysis methods. Then the authors analyze the effect of listing futures on the systemic risk in the spot market with the staggered difference-in-differences (DID) method.FindingsThe findings suggest that futures contracts help reduce systemic risks in the underlying spot network. Systemic risk for a commodity will decrease by approximately 5.7% with the introduction of each corresponding futures contract, since the hedging function of futures reduces the timing behavior of firms in the spot market. Establishing futures contracts for upstream commodities lowers systemic risks for downstream commodities. Energy commodities, such as crude oil and coal, have higher systemic importance, with the energy sector dominating systemic importance, while some chemical commodities also have considerable systemic importance. Meanwhile, the shortest transmission path for risk propagation is composed of the energy industry, chemical industry, agriculture/metal industry and final products.Originality/valueThe paper provides the following policy insights: (1) The role of futures contracts is still positive, and future contracts should be established upstream and at more systemically important nodes in the spot production chain. (2) More attention should be paid to the chemical industry chain, as some chemical commodities are systemically important but do not have corresponding futures contracts. (3) The risk source of the commodity spot market network is the energy industry, and therefore, energy-related commodities should continue to be closely monitored.

Automated Synthesis of Safe Timing Behaviors for Requirements Models Using CCSL

As a promising requirement-level specification language for timing behavior modeling, the Clock Constraint Specification Language (CCSL) has become popular in the model-driven design community for safety-critical embedded systems. However, due to the skyrocketing design complexity, in practice, it is hard for requirement engineers to accurately construct requirement models with expected timing behaviors using CCSL, especially for safe timing behaviors. Although more and more CCSL synthesis approaches are designed to facilitate the generation of CCSL specifications, most of them cannot be used directly for the synthesis of requirements models. This is because existing CCSL synthesis methods: i) focus on filling the holes of CCSL constraints rather than completing requirements models; and ii) rely heavily on limited observations of system behaviors, while the (temporal) safety properties of target systems are neglected. To address these issues, this paper proposes a novel method that enables the automated synthesis of safe timing behaviors for requirements models. By specifying the safety timing properties of target systems using safely-LTL, our approach adopts CCSL as an intermediate representation of requirement synthesis, where incomplete requirements models coupled with safely-LTL-based properties are encoded into CCSL constraints with holes. Guided by the samples (expected behaviors) provided by requirement engineers, our approach can automatically figure out the complete version of incomplete requirements models. Comprehensive experimental results on two complex case studies demonstrate that our approach can not only quickly and efficiently synthesize requirement models, but also guarantee that the synthesized models satisfy specified safety properties in Safely-LTL form.

Confronting the cycle synchronisation paradigm of defoliator outbreaks in space and time—Evidence from two systems in a mixed‐species forest landscape

Abstract Defoliators cause extensive damage in boreal and temperate forests of the world. Considerable effort has been invested to understand their individual population dynamics, and despite ample theorising, there is little empirical evidence on factors causing spatial synchrony of pest eruptions at landscape scales. We report on the landscape‐level effect of forest configuration and composition on the intensity of outbreaks of spruce budworm and forest tent caterpillar in a mixedwood boreal forest in northern Minnesota (USA) and adjacent Ontario (Canada), and how this is related to the degree of spatial synchrony in each species' outbreak cycling. Using a large spatiotemporal tree‐ring reconstruction of outbreak impacts across these two systems, we evaluate two contrasting theories governing defoliator outbreaks: harmonic oscillation (a.k.a. ‘clockwork’) and relaxation oscillation (a.k.a. ‘catastrophe’), each with consequences linked to top‐down versus bottom‐up influences on outbreak behaviour in time and space. We find synchrony varies temporally, among outbreak cycles and in direct proportion to cycle peak intensity; however, cycle peak intensities are distributed bimodally in time, and so, therefore, are synchrony coefficients. Spatially, the area where each pest species currently cycles with the greatest peak intensity and synchrony is where their preferred host trees are currently found in greatest proportion. Despite overall synchrony in cycling, we found, in both systems, a persistent negative spatial correlation among successive eruptive pulses of defoliation. Many of these eruptions failed to spread spatially and to coalesce with other spot eruptions to form extensive area‐wide outbreaks. Eruptions often fail to spread at the hardwood‐conifer interface, resulting in outbreak pulses that systematically bounce back and forth between landscape types, particularly when systems were cycling at low amplitude. These over‐dispersed spatial patterns of pulse impact are consistent with a contagious theory of eruption and outbreak spread. They could be considered consistent with harmonic oscillation theory only for populations cycling at different frequencies, with cycling frequency determined by host forest landscape structure. Synthesis. We find that defoliator outbreak dynamics across systems include spatiotemporal signatures of each theoretical paradigm—suggesting a hybrid approach will better characterise outbreak behaviour. Host concentration influences which paradigm dominates the spatial dynamics in any given forest landscape context. Because of the synchronising effect of host concentration on forest insect spatial dynamics, mixedwoods appear to be less prone to intense, synchronised defoliator attack than forests of pure hardwood or pure conifer.

Nanoclay-Doped Electrospun Nanofibers for Tissue Engineering: Investigation on the Structural Modifications in Physiological Environment.

Clay minerals are nanomaterials that have recently been recognized as enabling excipients that can promote cell adhesion, proliferation, and differentiation. When nanoclays are loaded in a 3D polymeric nanostructure, the cell-substrate interaction is enhanced, and other bioactive properties are optimized. In this study, hectorite (HEC)- and montmorillonite (MMT)-doped polymeric scaffolds were explored for the treatment of deep and chronic skin lesions. Scaffolds were manufactured by means of electrospinning and then crosslinked by heating. Physicochemical analyses were correlated with in vitro biopharmaceutical characterization to predict the in vivo fate of the clay-doped scaffolds. The addition of MMT or HEC to the polymeric scaffold framework modifies the surface arrangement and, consequently, the potential of the scaffolds to interact with biological proteins. The presence of nanoclays alters the nanofiber morphology and size, and MMT doping increases wettability and protein adhesion. This has an impact on fibroblast behavior in a shorter time since scaffold stiffness facilitates cell adhesion and cell proliferation. MMT proved to perform better than HEC, and this could be related to its higher hydrophilicity and protein adhesion.

Coupling by reflection for controlled diffusion processes: Turnpike property and large time behavior of Hamilton–Jacobi–Bellman equations

Coupling by reflection for controlled diffusion processes: Turnpike property and large time behavior of Hamilton–Jacobi–Bellman equations

The nonlocal dispersal equation with seasonal succession

In this paper, we focus on the nonlocal dispersal monostable equation with seasonal succession, which can be used to describe the dynamics of species in an environment alternating between bad and good seasons. We first prove the existence and uniqueness of global positive solution, and then discuss the long time behaviors of solution. It is shown that its dynamics is completely determined by the sign of the principal eigenvalue, i.e., the time periodic problem has no positive solution and the solution of the initial value problem tends to zero when principal eigenvalue is non-negative, while the time periodic positive solution exists uniquely and is globally asymptotically stable when principal eigenvalue is negative.

Off-axis emission of electrons by discharge of a low-inductance vacuum spark.

The article presents the results of the study of electrons, emitted by the plasma of a low-inductance vacuum spark. It was found that a 50-kA discharge with a 3.4-µs period of current oscillations produces electrons with the energy higher than 100 keV, which leave the discharge plasma in the direction perpendicular to the discharge axis. The electrons have an energy spectrum close to monoenergetic. They appear after the first quarter period of discharge current oscillations and are emitted during about 1 µs. So, the origin of the electrons has no relation to the process of plasma pinching. The time behavior of the electron energy was studied. It gradually diminishes from a value of about 100 keV just after the maximum of the discharge current down to about 10 kV after reversal of the current direction. This phenomenon points out the redistribution of the discharge current, resulting in the disappearance of the magnetic field on the line of sight perpendicular to the discharge axis.

Influence of COVID-19 on the emergence of stone-tool use behavior in a population of common long-tailed macaques (Macaca fascicularis fascicularis) in Thailand.

Stone tool use is a rare behavior across nonhuman primates. Here we report the first population of common long-tailed macaques (Macaca fascicularis fascicularis) who customarily used stone tools to open rock oysters (Saccostrea forskali) on a small island along the Thai Gulf in Koh Ped (KPE), eastern Thailand. We observed this population several times during the past 10 years, but no stone-tool use behavior was observed until our survey during the coronavirus disease 2019 (COVID-19) pandemic in July 2022. KPE is located in Pattaya City, a hotspot for tourism in Thailand. Tourists in this area frequently provided large amounts of food for the monkeys on KPE. During the COVID-19 curfew, however, tourists were not allowed to access the island, and monkeys began to face food scarcity. During this time, we observed stone-tool use behavior for the first time on KPE. Based on our observations, the first tool manipulation was similar to stone throwing (a known precursor of stone tool use). From our observations in March 2023, we found 17 subadult/adult animals performing the behavior, 15 of 17 were males and mostly solitary while performing the behavior. The M. f. fascicularis subspecies was confirmed by distribution, morphological characteristics, and mtDNA and SRY gene sequences. Taken together, we proposed that the stone tool use behavior in the KPE common long-tailed macaques emerged due to the COVID-19 food scarcity. Since traveling is no longer restricted many tourists have started coming back to the island, and there is a high risk for this stone tool-use behavior to disappear within this population of long-tailed macaques.

A mean field game approach for a class of linear quadratic discrete choice problems with congestion avoidance

This paper approaches large multi-agent dynamic discrete choice problems, such as those arising in crowd evacuation or micro-robotic-based exploration of unknown terrain, via a linear quadratic mean field games framework (LQ-MFG). Two particular features distinguish the proposed LQ-MFG: (i) agents have to reach within a fixed finite time one of a predefined set of possible destinations, which depend on their initial position; (ii) agent running costs can become negative as agents accrue a reward the further they remain from other agents aiming for the same set of destinations, so as to simulate crowd avoidance with limited surroundings awareness. The desirable tractability of the LQ-MFG setup must be balanced in this case by the fact that feature (ii) of the model can lead to agents escaping to infinity in finite time. An upper bound on the time horizon is derived to guarantee that the finite escape time behavior is avoided. The existence of a Nash equilibrium for the infinite population is then established, and it is shown that this equilibrium remains ɛ-Nash for the more realistic case of a large but finite population of agents. Finally, the model behavior is explored via simulations for different scenarios.

Tunable dynamic metamaterial for negative refraction

The effective ability to manipulate the negative refraction behaviors of electromagnetic waves in the terahertz (THz) frequency range is of great interest for various practical applications in communication, imaging, and sensing. In this study, we propose a robust graphene-integrated metamaterial design for the dynamic manipulation of negative refraction at terahertz frequencies. Using the distinctive characteristics of graphene combined with the specially designed metamaterial structure, we demonstrated the active control of negative refraction by modulating the graphene's chemical potential from 0.0 to 1.0 eV. By dynamically tuning the carrier density of graphene, we create the switchable states of the negative index for the transmission or the reflection modes, tailoring the terahertz wave behavior in real time. In particular, in the case of different applied temperatures (through the bias applied voltages) of the proposed metamaterial, these two modes are maintained over 60% for both reflection and transmission while preserving the negative refractive index. Our results reveal the tunability of negative refraction, paving the way for developing reconfigurable THz meta-devices with enhanced functionalities in the near future.

Broadband X-Ray Timing and Spectral Characteristics of the Accretion-powered Millisecond X-Ray Pulsar MAXIJ1816-195

We studied the broadband X-ray timing and spectral behaviors of the newly confirmed accreting millisecond X-ray pulsar MAXI J1816−195 during its 2022 outburst. We used data from the Insight-HXMT Medium Energy (ME) and High Energy (HE) telescopes, NICER, and NuSTAR that cover the energy range between 0.8 and 210 keV. A coherent timing analysis of solely the Insight-HXMT HE data across the full outburst revealed a complex behavior of the timing residuals, also prominently visible in the independent Insight-HXMT ME and NICER data, particularly at the rising part of the outburst and at the very end in the NICER data. Therefore, we broke down the full outburst into a (noisy) rising part, covering only about five days, from MJD 59737.0 to 59741.9, and a decaying part, lasting for 19 days across MJD 59741.9–59760.6. Fitting for the decaying part, a timing model including a frequency ν and frequency time derivative component yielded a value of (+9.0 ± 2.1) × 10−14 Hz s−1 for , which could be interpreted as a spinup under our model assumptions. We detected X-ray pulsations up to ∼95 keV in a combination of Insight-HXMT HE observations. The pulse profiles were quite stable over the whole outburst and could be well described by a truncated Fourier series using two harmonics, the fundamental and the first overtone. Both components kept alignment in the range 0.8–64 keV. The joint and time-averaged NICER and Insight-HXMT spectra in the energy range 1–150 keV were well fitted by the absorbed Comptonization model compps plus disk blackbody with two additional Gaussian components. Using the bolometric flux and spinup values both evaluated during the decay phase, we determined a magnetic field strength of (0.2–2) × 108 G for MAXI J1816−195.

Decay rates of convergence for Fokker-Planck equations with confining drift

We consider Fokker-Planck equations in the whole Euclidean space, driven by Levy processes, under the action of confining drifts, as in the classical Ornstein-Ulhenbeck model. We introduce a new PDE method to get exponential or sub-exponential decay rates, as time goes to infinity, of zero average solutions, under some diffusivity condition on the Levy process, which includes the fractional Laplace operator as a model example. Our approach relies on the long time oscillation estimates of the adjoint problem and applies to (the possible superposition of) both local and nonlocal diffusions, as well as to strongly or weakly confining drifts. Our results extend, with a unifying perspective, many previous works based on different analytic or probabilistic methods, with several interesting connections. On one hand, we make a link between the (nonlinear) PDE methods used for the long time behavior of Hamilton-Jacobi equations and the decay estimates of Fokker-Planck equations; on another hand, we give a purely analytical approach towards some oscillation decay estimates which were obtained so far only with probabilistic coupling methods.

Tongue and laryngeal exercises improve tongue strength and vocal function outcomes in a Pink1-/- rat model of early Parkinson disease

Parkinson disease (PD) causes voice and swallow dysfunction even in early stages of the disease. Treatment of this dysfunction is limited, and the neuropathology underlying this dysfunction is poorly defined. Targeted exercise provides the greatest benefit for offsetting voice and swallow dysfunction, and previous data suggest the hypoglossal nucleus and noradrenergic-locus coeruleus (LC) may be involved in its early pathology. To investigate relationships between targeted exercise and neuropathology of voice and swallow dysfunction, we implemented a combined exercise paradigm that included tongue force and vocalization exercises early in the Pink1-/- rat model. We tested the hypotheses that (1) tongue and vocal exercise improves tongue force and timing behaviors and vocalization outcomes, and (2) exercise increases optical density of serotonin (5-HT) in the hypoglossal nucleus, and tyrosine hydroxylase immunoreactive (Th-ir) cell counts in the LC. At two months of age Pink1-/- rats were randomized to exercise or non-exercise treatment. Age-matched wildtype (WT) control rats were assigned to non-exercise treatment. Tongue force and timing behaviors and ultrasonic vocalizations were measured at baseline (two months) and final (four months) timepoints. Optical density of 5-HT in the hypoglossal nucleus and TH-ir cell counts in the LC were obtained. Pink1-/- rats produced greater tongue forces, faster tongue contraction, and higher-intensity vocalization following exercise. There were no differences in LC TH-ir. The non-exercised Pink1-/- group had reduced density of 5-HT in the hypoglossal nucleus compared to the WT control group. The changes to tongue function and vocalization after targeted exercise suggests exercise intervention may be beneficial in early PD.

Large time behavior in a reaction diffusion epidemic model with logistic source

This paper concerns a reaction diffusion epidemic model under logistic source. First, we explore uniform boundedness of the system. Moreover, by constructing two Lyapunov functions, we show that the disease-free equilibrium of system is globally asymptotically stable and the large time dynamics of constant endemic equilibrium is also considered. Especially, we further investigate the convergence rate of the nonnegative globally bounded classical solution. Finally, two numerical simulations are displayed to confirm the results.