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Chlorophyll in phytoplankton absorbs solar radiation (SR) and affects the thermal structure and dynamics within upwelling regions. However, research on this process across global‐scale coastal upwelling systems is still lacking. Here, we use a coupled ocean‐biogeochemical model to investigate differing responses to chlorophyll‐induced solar absorption between Pacific and Atlantic coastal upwelling regions. Chlorophyll‐induced solar absorption leads to colder Pacific coastal upwelling but warmer Atlantic coastal upwelling. In the Pacific, the shading effect of the surface chlorophyll maximum leads to colder subsurface water, which is then upwelled, contributing to cooling. The more stratified upper ocean leads to shallower mixed layer depth, intensifying offshore transport and upwelling. In the Atlantic, the absorption of SR by the subsurface chlorophyll maximum causes warmer and weaker upwelling. The processes described, in turn, trigger positive feedback to ocean biogeochemistry and potentially interact with climate dynamics, underscoring the necessity to incorporate them into Earth system models. Plain Language Summary: Chlorophyll and related pigments in phytoplankton play a key role in absorbing solar radiation and regulating ocean temperatures. In some coastal upwelling regions along the eastern boundaries of oceans, where chlorophyll concentrations are high, studies have suggested that the solar heat absorbed by chlorophyll can influence the temperatures and strength of upwelling. However, there is no study focusing on this process across global coastal upwelling zones. Here, we use computer simulations of ocean and phytoplankton to explore the effects of chlorophyll‐induced solar absorption on upwelling temperatures and strength on a global scale. Our study suggests that this effect varies between Pacific and Atlantic coastal upwelling regions due to their different spatial distributions of chlorophyll: surface chlorophyll in the Pacific warms the water after it has risen to the surface and as it is flowing offshore, while subsurface chlorophyll in the Atlantic warms the water before it rises to the surface. As a result, chlorophyll‐induced solar absorption leads to colder and stronger coastal upwelling in Pacific but warmer and weaker upwelling in Atlantic. Given the limited consideration of this process in previous studies, we emphasize the importance of incorporating it, along with regional differences, into future simulations. Key Points: Chlorophyll‐induced solar absorption leads to colder Pacific coastal upwelling but warmer Atlantic coastal upwellingIn Pacific, chlorophyll‐induced temperature variations intensify ocean stratification and coastal upwelling, in contrast to AtlanticChlorophyll‐induced variations in ocean physics trigger positive feedback, enhancing chlorophyll distributions in coastal upwelling regions [ABSTRACT FROM AUTHOR]

The relativistic Sunyaev-Zel'dovich (SZ) effect can be used to measure intracluster gas temperatures independently of X-ray spectroscopy. Here, we use the large-volume FLAMINGO simulation suite to determine whether SZ y -weighted temperatures lead to more accurate hydrostatic mass estimates in massive (⁠|$M_{\rm 500c} \gt 7.5\times 10^{14}\, {\rm M}_{\odot }$|⁠) clusters than when using X-ray spectroscopic-like temperatures. We find this to be the case, on average. The median bias in the SZ mass at redshift zero is |$\left\langle b \right\rangle \equiv 1-\left\langle M_{\rm 500c,hse}/M_{\rm 500c,true} \right\rangle = -0.05 \pm 0.01$|⁠ , over 4 times smaller in magnitude than the X-ray spectroscopic-like case, |$\left\langle b \right\rangle = 0.22 \pm 0.01$|⁠. However, the scatter in the SZ bias, |$\sigma _{b} \approx 0.2$|⁠ , is around 40 per cent larger than for the X-ray case. We show that this difference is strongly affected by clusters with large pressure fluctuations, as expected from shocks in ongoing mergers. Selecting the clusters with the best-fitting generalized NFW pressure profiles, the median SZ bias almost vanishes, |$\left\langle b \right\rangle = -0.009 \pm 0.005$|⁠ , and the scatter is halved to |$\sigma _{b} \approx 0.1$|⁠. We study the origin of the SZ/X-ray difference and find that, at |$R_{\rm 500c}$| and in the outskirts, SZ weighted gas better reflects the hot, hydrostatic atmosphere than the X-ray weighted gas. The SZ/X-ray temperature ratio increases with radius, a result we find to be insensitive to variations in baryonic physics, cosmology, and numerical resolution. [ABSTRACT FROM AUTHOR]

Unsteady flow distortion is of interest for the development of air-breathing propulsion systems. Stochastic fluctuations can generate incompatibilities between intakes and aero-engines. Observing the extreme flow distortion events during experimental testing is not guaranteed and statistical models such as extreme value theory (EVT) can be used to estimate the occurrence and magnitude of the fluctuations. However, the current industry standard does not provide guidance on how to apply these methods to obtain useful predictions. This work proposes a systematic process to assess the required number of observations for obtaining statistical convergence of the EVT predictions. This is achieved through shuffling of the data samples and relies on the availability of a sufficiently large initial dataset. This can be adopted by gas turbine engineers to evaluate the data recording requirements and to potentially reduce costs associated with experimental programs. [ABSTRACT FROM AUTHOR]

Experimental studies have shown that many natural and artificial systems need to maintain stable oscillations during application, but the occurrence of oscillation quenching phenomenon will destroy the oscillation activity of the system and hinder the normal operation of the system. In this paper, to solve the important problem of oscillation quenching leading to system paralysis, the weighted average function of oscillators is applied to each oscillator as an external feedback, which is an extension of the mean-field feedback [N. Zhao and Z. Sun, Int. J. Bifurcation Chaos 30, 2050094 (2020)]. Taking the Stuart–Landau oscillators with the identical and nonidentical frequencies as examples, respectively, we find that the weighted average feedback is better than the previously proposed mean-field feedback in eliminating oscillation quenching with different coupling scenarios. Especially, when the weight is 0 or 1, that is, when a single oscillator is used as the feedback, the weighted average feedback is highly efficient in reviving oscillation. Our results provide a more convenient method to overcome these quenching states of coupled systems, and broaden the practical applications with respect to revoking rhythmic oscillations via external feedback in nature and real life. [ABSTRACT FROM AUTHOR]

The deep-ultra deep carbonate reservoir in China, commonly subjected to modification of multi-stage diagenesis, has extremely high heterogeneity. Conventional rock physics analysis cannot accurately identify the elastic responses of reservoir. Here, the rock physics properties of the dolomite from the 4th Member of the Sinian Dengying Formation are experimentally measured, and the change law of rock physics characteristics is investigated within the framework of the diagenetic processes by the analysis of the elastic and petrologic characteristics, pore structure, and sedimentary environments. The results show that the differentiated diagenesis results in different pore structure characteristics and microtexture characteristics of the rock. The microbial dolomite of the algal mound-grain beach facies is subjected to the contemporaneous microbial dolomitization and seepage-reflux dolomitization, penecontemporaneous selective dissolution, burial dolomitization, and hydrothermal dolomitization. The resultant crystalline dolomite is found with one main type of the dolomite crystal contact boundaries, and the dissolution pore is extensive development. The siliceous, muddy, and limy dolomite of the interbeach sea environment mainly experiences the weak capillary concentration dolomitization, intensive mechanical compaction-induced densification, and burial dolomitization. Such crystalline dolomite is observed with four types of contact boundaries, namely the dolomite contact, clay contact, quartz contact, and calcite contact boundaries, and porosity mostly attributed to residual primary inter-granular or crystalline pores. The samples with the same crystal boundary condition have consistent correlations between the compressional- and shear-wave velocities, and between the compressional-wave velocity and the velocity ratio. Additionally, the variation of the acoustic velocity with effective pressure and the intensity of pore-scale fluid-related dispersion are controlled by the differentiation of pore structure types of the samples. The varied effects of soft pores like micro-cracks on the compressional- and shearwave velocity causes considerable changes in the relationships between the compressional- and shearwave velocities, compressional-wave velocity and velocity ratio, and porosity and acoustic velocity. This research is an attempt to demonstrate a novel method for investigating the rock physics variation of rock during the geological process, and the obtained findings can provide the rock physics basis for seismic prediction of the characteristics of deep carbonate reservoirs. [ABSTRACT FROM AUTHOR]

This paper utilizes the theory of quantum diffusion to analyze the electron probability and spreading width of a wavepacket on each layer in a two-dimensional (2D) coupled system with edge disorder, aiming to clarify the effects of edge disorder on the stability of the electron periodic oscillations in 2D coupled systems. Using coupled 2D square lattices with edge disorder as an example, we show that, the electron probability and wavepacket spreading width exhibit periodic oscillations and damped oscillations, respectively, before and after the wavepacket reaches the boundary. Furthermore, these electron oscillations exhibit strong resistance against disorder perturbation with a longer decay time in the regime of large disorder, due to the combined influences of ordered and disordered site energies in the central and edge regions. Finally, we numerically verified the universality of the results through bilayer graphene, demonstrating that this anomalous quantum oscillatory behavior is independent of lattice geometry. Our findings are helpful in designing relevant quantum devices and understanding the influence of edge disorder on the stability of electron periodic oscillations in 2D coupled systems. [ABSTRACT FROM AUTHOR]

The Pólya urn is the most representative example of a reinforced stochastic process. It leads to a random (non degenerated) time-limit. The Friedman urn is a natural generalization whose almost sure (a.s.) time-limit is not random any more. In this work, in the stream of previous recent works, we introduce a new family of (finite size) systems of reinforced stochastic processes, interacting through an additional collective reinforcement of mean field type. The two reinforcement rules strengths (one component-wise, one collective) are tuned through (possibly) two different rates. In special cases, these reinforcements are of Pólya or Friedman type as in urn contexts and may thus lead to limits which may be random or not. Different parameter regimes need to be considered. We state two kind of results. First, we study the time-asymptotic and show that L2 and a.s. convergence always holds. Moreover, all the components share the same time-limit (so called synchronization phenomenon). We study the nature of the limit (random/deterministic) according to the parameters' regime considered. Second, we study fluctuations by proving central limit theorems. Scaling coefficients vary according to the regime considered. This gives insights into many different rates of convergence. In particular, we identify the regimes where synchronization is faster than convergence toward the shared time-limit. [ABSTRACT FROM AUTHOR]

In order to study the combustion instability of solid rocket motors, the vibration-acoustic vibration-burning rate oscillation-thrust oscillation coupling system of solid rocket motors is analyzed. In this paper, a numerical model covering the pressure oscillation, combustion, pseudo-one-dimensional fluid field, and overall thrust is built. We investigate the thrust oscillation caused by projectile structure vibration and the response characteristics of thrust oscillation. By conducting a sine sweep test, we obtain the response function of thrust in relation to pressure oscillation. A physical experiment shows that the calculated frequency response function is consistent with the experimental results. [ABSTRACT FROM AUTHOR]

While Ising criticality in classical liquids has been firmly established both theoretically and experimentally, much less is known about criticality in liquids in which the growth of the correlation length is frustrated by finite-size effects. A theoretical approach for dealing with this issue is the random-field Ising model (RFIM). While experimental critical-exponent values have been reported for magnetic samples (here, we consider γ , ν and η), little experimental information is available for critical fluctuations in corresponding liquid systems. In this paper, we present a study on a binary liquid consisting of 3-methyl pyridine and heavy water in a very light-weight porous gel. We find that the experimental results are in agreement with the theoretical predictions from the RFIM. [ABSTRACT FROM AUTHOR]

Human experience is imbued by the sense of being an embodied agent. The investigation of such basic self-consciousness has been hampered by the difficulty of comprehensively modulating it in the laboratory while reliably capturing ensuing subjective changes. The present preregistered study fills this gap by combining advanced meditative states with principled phenomenological interviews: 46 long-term meditators (19 female, 27 male) were instructed to modulate and attenuate their embodied self-experience during magnetoencephalographic monitoring. Results showed frequency-specific (high-beta band) activity reductions in frontoparietal and posterior medial cortices (PMC). Importantly, PMC reductions were driven by a subgroup describing radical embodied self-disruptions, including suspension of agency and dissolution of a localized first-person perspective. Neural changes were correlated with lifetime meditation and interview-derived experiential changes, but not with classical self-reports. The results demonstrate the potential of integrating in-depth first–person methods into neuroscientific experiments. Furthermore, they highlight neural oscillations in the PMC as a central process supporting the embodied sense of self. [ABSTRACT FROM AUTHOR]

Suppose p is a prime and T is a non-identity Sylow p -subgroup of a finite group G for which C G (O p (G)) ⩽ O p (G). D. Bundy, N. Hebbinghaus, and B. Stellmacher determined the structure of G in an important case in which C G (Ω 1 (Z (T))) and N G (B e (T)) generate a proper subgroup of G , where B e (T) is the Baumann subgroup of T according to a particular definition. We apply their theorem to prove an analogous theorem that uses a different definition of the Baumann subgroup. This result is applied in a related article to prove a transfer theorem for odd primes. [ABSTRACT FROM AUTHOR]

Based on the enormous application potential of GaN-based high electron mobility transistors (HEMT) in high-frequency and high-power scenarios, this article focuses mainly on the study of the Gunn oscillation effect of GaN-based HEMT devices. From the perspective of electric field regulation, a sandwich structure GaN HEMT device model with field plate structure is proposed, and a hydrodynamic physical model is established. The negative resistance characteristics in the GaN HEMT are obtained by the finite element method and the influence of the gate field plate on the Gunn oscillation frequency in the device channel is studied. The numerical simulation results show that the suitable field plate structure can modulate the distribution of the channel electric field below the gate, promote the electric field to enter the negative differential mobility region, undergo valley to valley electron transfer, form electron domains, and generate the Gunn oscillation currents in the terahertz band. Meanwhile, the length of the field plate regulates the oscillation current frequency of the device, and the stable and usable terahertz frequency band signal can be realized. This research opens up the possibility for semiconductor solid-state devices to realize terahertz frequency band radiation, and provides the basis for realizing new breakthroughs in HEMT for terahertz applications. [ABSTRACT FROM AUTHOR]

The dynamics of a solid spherical body in an oscillating liquid flow in a vertical axisymmetric channel of variable cross section is experimentally studied. It is shown that the oscillating liquid leads to the generation of intense averaged flows in each of the channel segments. The intensity and direction of these flows depend on the dimensionless oscillating frequency. In the region of studied frequencies, the dynamics of the considered body is examined when the primary vortices emerging in the flow occupy the whole region in each segment. For a fixed frequency, an increase in the oscillation amplitude leads to a phase-inclusion holding effect, i.e., the body occupies a quasi-stationary position in one of the cells of the vertical channel, while oscillating around its average position. It is also shown that the oscillating motion of a liquid column generates an averaged force acting on the body, the magnitude of which depends on the properties of the body and its position in the channel. The quasi-stationary position is determined by the relative density and size of the body, as well as the dimensionless frequency. The behavior of the body as a function of the amplitude and frequency of fluid oscillation and relative size is discussed in detail. Such findings may be used in the future to control the position of a phase inclusion and/or to strengthen mass transfer effects in a channel of variable cross section by means of fluid oscillations. [ABSTRACT FROM AUTHOR]

In this paper, theoretical and numerical analysis of a transonic flow field of critical flow Venturi nozzles according to the ISO 9300 standard is performed. Deviations of the flow field from an estimate based on one dimensionality are clarified. While the theoretical analysis allows prediction of these deviations, the numerical analysis allows quantification of their influence. The main studied phenomena include the local supersonic compression in transonic expansion and the Prandtl-Meyer expansion. The tendency of the flow field to spatial oscillations is shown, alongside the ability of the system to damp these oscillations. [ABSTRACT FROM AUTHOR]

The electronic, phonon, and superconducting properties of hexagonal yttrium hydrogen selenide (YHSe) are studied using density functional theory (DFT) methods. The DFT analysis revealed that the energy bandgap and density of states near the Fermi energy (ɛF) decrease with increasing pressure. Additionally, the influence of pressure on the vibrational properties of YHSe is also examined. The findings of the vibrational properties indicate a stiffening of lattice dynamics under pressure and the identification of negative Gruneisen parameters at certain high symmetry sites. This enhances and deepens the understanding of the vibrational characteristics of YHSe under extreme pressure conditions. Finally, the electron–phonon coupling (EPC) parameter (λ) is examined under different pressures. The examination of EPCs across varying pressures showed a significant increase from 0.826 (0 GPa) to 2.6287 (200 GPa), where an increase in this EPC is found to increase the superconducting critical temperature (Tc). Furthermore, the nonmonotonic relationship between the superconducting critical temperature (Tc) and external pressure (P) in the YHSe compound is observed. Initially, Tc decreases with increasing pressure and then begins to rise again, reaching its peak value at extreme pressure. These findings provide valuable insights into the pressure-dependent properties of YHSe and have important implications for the field of superconductivity in condensed matter physics. [ABSTRACT FROM AUTHOR]

Cyclic rodent populations exhibit pronounced changes in body mass associated with the population cycle phase, long-known as Chitty effect. Although Chitty effect is a common epiphenomenon in both America and Europe, there is still incomplete evidence about the generality of these patterns across the entire range of most species. Moreover, despite decades of research, the underlying factors driving Chitty effect remains poorly understood. Here, we examined the influence of intrinsic and extrinsic factors that may underlie observed patterns in vole size variation in the Iberian common vole Microtus arvalis asturianus. We weighed and measured 2816 adult voles that were captured during 6 trapping periods. Vole numbers and body mass showed strong period- and phase-related variation both in females and males, demonstrating marked Chitty effect in the studied population. Body mass of adult males correlated with body length, evidencing that heavier males are also structurally larger. Statistical models showed that probability of occurrence of large-sized vole (> 37 g) was significantly more likely in reproductive males, during increase and peak phases, and it was modulated by habitat, with crop fields and field margins between crops showing an increased likelihood. We suggest an effect of the habitat on vole body mass mediated by predation. [ABSTRACT FROM AUTHOR]

Topological flat bands — where the kinetic energy of electrons is quenched — provide a platform for investigating the topological properties of correlated systems. Here, we report the observation of a topological flat band formed by polar-distortion-assisted Rashba splitting in the three-dimensional Dirac material ZrTe5. The polar distortion and resulting Rashba splitting on the band are directly detected by torque magnetometry and the anomalous Hall effect, respectively. The local symmetry breaking further flattens the band, on which we observe resistance oscillations beyond the quantum limit. These oscillations follow the temperature dependence of the Lifshitz–Kosevich formula but are evenly distributed in B instead of 1/B at high magnetic fields. Furthermore, the cyclotron mass gets anomalously enhanced about 102 times at fields ~ 20 T. Our results provide an intrinsic platform without invoking moiré or order-stacking engineering, which opens the door for studying topologically correlated phenomena beyond two dimensions. Topological flat bands offer a solid-state platform for studying the interplay between topology and electron correlations. Here, the authors demonstrate that a prototypical 3D Dirac material can host topological flat bands under magnetic fields due to polar-distortion-assisted Rashba splitting. [ABSTRACT FROM AUTHOR]

A new four-dimensional chaotic system with high complexity is proposed, and the analysis of its dynamics reveals that the system shows a rare topological attractor structure symmetry phenomenon. The phenomenon of inverse multiplicative bifurcation and multistability, which changes from a quadruple period to a double period and then to a single period, are found. A complex oscillatory transformation between chaos and period can be observed, highlighting the complexity of the system. The transient hyperchaos and burst oscillations are found in the time series and Lyapunov exponential spectra of the system, and the rich dynamical behavior of the system is verified by the 0–1 test and complexity spectral entropy test. The analog circuitry of the system is simulated based on Multisim, and the actual digital circuitry of the system is implemented through a Field Programmable Gate Array. The experimental results and the numerical simulation results agree and prove the feasibility of the constructed system. An image encryption algorithm is designed by combining the disruption-diffusion algorithm with the DNA encoding algorithm, and the system is analyzed and verified to be highly sensitive to the chaotic sequence key and initial value. Moreover, the key space of the algorithm is large and the information entropy is close to the ideal value, so the new system proposed can contribute to play a role in the field of secure communication. [ABSTRACT FROM AUTHOR]

This paper presents an in-depth analysis of the oscillation phenomenon occurring in multi-chip parallel automotive-grade power modules under short-circuit conditions and investigates three suppression methods. We tested and analyzed two commercial automotive-grade power modules, one containing two chips and the other containing a single chip, and found that short-circuit gate oscillations were more likely to occur in multi-chip parallel packaged modules than in single-chip packaged modules. Through experimental and simulation analyses, we observed that gate oscillations were mainly caused by the interaction between internal parasitic parameters of the module and the external drive circuit, and we found that high drive resistance and low common emitter inductance between parallel chips could effectively suppress gate voltage oscillations. We also analyzed the two mainstream suppression schemes, increasing the drive gate resistance and placing the drive capacitors in parallel. Unfortunately, we found that these suppression schemes were not ideal solutions because both schemes changed the switching characteristics of the power module. As an alternative, we propose a simple and effective solution that involves adding parallel connections between the parallel chips. Simulation calculations showed that this optimized method reduced the emitter inductance between parallel chips in the upper bridge arm by about 30% and in the lower bridge arm by 35%. Through short-circuit experiments conducted at different DC bus voltages, it has been verified that the new optimized solution effectively resolves gate oscillation issues without affecting the switching characteristics of the power module. [ABSTRACT FROM AUTHOR]

Memristors have several chaotic dynamic models and have been used successfully in various fields, including secure communication systems, information storage, and artificial neural networks. The memristor-based four-dimensional chaotic (FDMC) systems generate unpredictable and intricate time domain signals. Parameter fluctuations in the FDMC system may give birth to chaos, making it difficult to suppress. Stabilizing chaos in the FDMC system improves the circuit's performance. This paper synthesizes a novel time-efficient chatter-free nonlinear robust adaptive control (NLRAC) technique that stabilizes chaos in the FDMC system affected by time-varying unknown bounded exogenous disturbances and model uncertainties. The proposed NLRAC strategy decimates the time-varying unknown bounded exogenous disturbances and model uncertainties effects; it establishes a faster, smoother state-variable trajectories convergence to the zero vicinity. The theoretical analysis and mathematical proofs are based on the Lyapunov stability technique. Computer simulation results show that the proposed NLRAC technique effectively brings the FDMC system's state-variable trajectories to zero with reduced fluctuations for control input signals and state-variable trajectories. This feedback controller's attribute enhances closed-loop stability performance, improves precision, and reduces risk overshoot. The paper includes comparative computer simulation results to endorse the proposed controller performance. [ABSTRACT FROM AUTHOR]

Configurational sampling is central to characterize the equilibrium properties of complex molecular systems, but it remains a significant computational challenge. The conventional molecular dynamics (MD) simulations of limited duration often result in inadequate sampling and thus inaccurate equilibrium estimates. Replica exchange with nonequilibrium switches (RENS) is a collective variable-free computational technique to achieve extensive sampling from a sequence of equilibrium and nonequilibrium MD simulations without modifying the underlying potential energy surface of the system. Unlike the conventional replica exchange molecular dynamics (REMD) simulation, which demands a significant number of replicas for better accuracy, RENS employs nonequilibrium heating (forward) and cooling (reverse) work simulations prior to configurational swaps to improve the acceptance probability for replica exchange by using only a few replicas. Here, we have implemented the RENS algorithm on four model systems and examined its performance against the conventional MD and REMD simulations. The desired equilibrium distributions were generated by RENS for all the model systems, whereas REMD and MD simulations could not do so due to inadequate sampling on the same timescales. The calculated work distributions from RENS obeyed the expected nonequilibrium fluctuation theorem. The results indicate that the switching time of the nonequilibrium simulations can be systematically altered to optimize the acceptance probability and the reduced work of switching. The modular implementation of RENS algorithm not only enables us to readily extend it to multiple replicas but also paves the way for extension to larger molecular systems in the future. [ABSTRACT FROM AUTHOR]

A dense particle suspension under shear may lose its uniform state to large local density and stress fluctuations, which challenge the mean-field description of the system. Here, we explore the novel dynamics of a non-Brownian suspension under orbital oscillations, where localized density waves along the flow direction appear beyond an excitation frequency threshold and self-organize into a hexagonal pattern across the system. The spontaneous occurrence of the inhomogeneity pattern arises from a coupling between particle advection and the shear-thickening nature of the suspension. Through linear stability analysis, we show that they overcome the stabilizing effects of particle pressure at sufficient particle volume fraction and oscillation frequency. In addition, the long-standing density waves degenerate into random fluctuations when replacing the free surface with rigid confinement. It indicates that the shear-thickened state is intrinsically heterogeneous, and the boundary conditions are crucial for developing local disturbance. [ABSTRACT FROM AUTHOR]

In this article, we study the fluctuations of the empirical occupa)tion measures of servers around their mean-field limit in a large system of heterogeneous processor sharing servers. It is assumed that there are M different servers grouped by their speeds and that the total number of servers is N. In particular, we study the sensitivity of the fluctuations to arrival rate parameters at the diffusion scale. The job arrival process is assumed to be Poisson with rate N(λ − β/√N ) and the job lengths are assumed to be exponentially distributed with unit mean. On arrival, a finite number of servers from each group are selected and the destination server depends on the server occupancy normalized to their speeds and pre-defined thresholds, referred to as the Join-Below-Threshold scheme. We derive Functional Central Limit Theorems (FCLTs) for the fluctuations that enable us to estimate the error of the mean field approximations to the empirical measures associated with a system with N servers. We then use these results to show mean response time for finite systems can be approximated by the response time given by the mean-field limit and the error isO( 1/√N ) for which the constants can be precisely calculated. [ABSTRACT FROM AUTHOR]

Using the non-equilibrium molecular dynamics (NEMD) simulations and the time-dependent Ginzburg–Landau (TDGL) theory for solidification kinetics, we study the crystal-melt interface (CMI) kinetic coefficients for both the soft-sphere (SS) BCC-melt and the FCC-melt interfaces, modeled with the inverse-power repulsive potential ( n = 8 ). The collective dynamics of the interfacial liquids at four equilibrium CMIs are calculated and employed to eliminate the discrepancy between the predictions of the kinetic coefficient using the NEMD simulations and the TDGL solidification theory. The speedup of the two modes of the interfacial liquid collective dynamics (at wavenumbers equal to the principal and the secondary reciprocal lattice vector of the grown crystal) at the equilibrium FCC CMI is observed. The calculated local collective dynamics of the SS BCC CMIs are compared with the previously reported data for the BCC Fe CMIs, validating a hypothesis proposed recently that the density relaxation times of the interfacial liquids at the CMIs are anisotropic and material dependent. With the insights provided by the improved application of the TDGL solidification theory, an attempt has been made to interpret the variation physics of the crystal-structure dependence of the solidification kinetic coefficient. [ABSTRACT FROM AUTHOR]

Introduction: Neural interactions in the brain are affected by transmission delays which may critically alter signal propagation across different brain regions in both normal and pathological conditions. The effect of interaction delays on the dynamics of the generic neural networks has been extensively studied by theoretical and computational models. However, the role of transmission delays in the development of pathological oscillatory dynamics in the basal ganglia (BG) in Parkinson's disease (PD) is overlooked. Methods: Here, we investigate the effect of transmission delays on the discharge rate and oscillatory power of the BG networks in control (normal) and PD states by using a Wilson-Cowan (WC) mean-field firing rate model. We also explore how transmission delays affect the response of the BG to cortical stimuli in control and PD conditions. Results: Our results show that the BG oscillatory response to cortical stimulation in control condition is robust against the changes in the inter-population delays and merely depends on the phase of stimulation with respect to cortical activity. In PD condition, however, transmission delays crucially contribute to the emergence of abnormal alpha (8-13 Hz) and beta band (13-30 Hz) oscillations, suggesting that delays play an important role in abnormal rhythmogenesis in the parkinsonian BG. Discussion: Our findings indicate that in addition to the strength of connections within and between the BG nuclei, oscillatory dynamics of the parkinsonian BG may also be influenced by inter-population transmission delays. Moreover, phase-specificity of the BG response to cortical stimulation may provide further insight into the potential role of delays in the computational optimization of phase-specific brain stimulation therapies. [ABSTRACT FROM AUTHOR]

Ship stability is one of the most valuable operational situations of ships and provides essential information on the weather conditions, safety and control ability of the ship. To guarantee a ship's sustainability, there is an urgent need to analyze and apply the results of vessel manoeuvring dynamics and establish the controller's design thereby assuring the ship's performance. To address the problem, this study introduces a modified form of the linear quadratic regulator (LQR) controller design to control and influence the random fluctuations in the system state measurements stable results were obtained in the various cases that were tested. The controller was robust enough to deal with measurement noise under varying circumstances. Considering the vessel's turning radius bend of 300 millimeters and the completion of a full turn in 3.5 minutes, the performance of the controller tested in a real situation reveals that increasing the controller gains through the values of the Q and R (quadratic regulator) matrices affected different parts of the response. Furthermore, from the simulation, for every 1 second of simulation time, we have 20.85 seconds of real-time. The real-time plots provided are 0.24 seconds of simulation time. Also, the higher value of the Q matrix coefficients stimulated a faster response since the feedback gain increases commensurately. The result is significant as it enables naval architects to easily manoeuvre vessels in a predictable way which is the effect of this controller design. [ABSTRACT FROM AUTHOR]

The next generation of ultrahigh bypass ratio civil aero-engines promises notable engine cycle benefits. However, these benefits can be significantly eroded by a possible increase in nacelle weight and drag due to the typical larger fan diameters. More compact nacelles, with shorter intakes, may be required to enable a net reduction in aero-engine fuel burn. The aim of this paper is to assess the influence of the design style of short intakes on the unsteady interaction under crosswind conditions between fan and intake, with a focus on the separation onset and characteristics of the boundary layer within the intake. Three intake designs were assessed, and a hierarchical computational fluid dynamics (CFD) approach was used to determine and quantify primary aerodynamic interactions between the fan and the intake design. Similar to previous findings for a specific intake configuration, both intake flow unsteadiness and the unsteady upstream perturbations from the fan have a detrimental effect on the separation onset for the range of intake designs. The separation of the boundary layer within the intake was shock driven for the three different design styles. The simulations also quantified the unsteady intake flows with an emphasis on the spectral characteristics and engine-order signatures of the flow distortion. Overall, this work showed that is beneficial for the intake boundary layer to delay the diffusion closer to the fan and reduce the preshock Mach number to mitigate the adverse unsteady interaction between the fan and the shock. [ABSTRACT FROM AUTHOR]

A physics-based low frequency noise (LFN) model for AlxGa1−xN/GaN high electron mobility transistors (HEMTs) is proposed in this article. By treating the distributed low-density surface donor states as the responsible mechanism and exhibiting charge neutrality in combination with the electric field across the barrier layer, a compact expression for Schottky barrier height (SBH) capturing the physics behind the variations of AlxGa1−xN layer thickness is profiled, which incorporates the effect of strain relaxation caused by high Al fraction. Furthermore, the SBH is applied to develop VTH and IDS. The LFN model, dominated by the fluctuations of carriers and drain current in the channel caused by the trapping/detrapping process, is subsequently obtained. It is indicated that the larger threshold voltage, higher drain current, and normalized noise are observed by our model with respect to the traditional SBH expressed only by an interpolated linear function of x. The drain current noise behavior showing the 1/f spectrum down to very low frequencies is seriously subjected to the barrier thickness-dependent SBH of AlxGa1−xN/GaN HEMTs. The accuracy of the proposed model is also verified by comparison with the experimental results from different devices. [ABSTRACT FROM AUTHOR]

The east–west component of the geomagnetic field (Y‐component) at the Trivandrum (TRD) station, an equatorial site, is used to investigate the characteristics of Inter‐Hemispheric Field‐Aligned Currents (IHFACs) in the Indian sector during solar cycles 21 and 22. The observations reveal an annual variation of IHFAC in the dawn/noon sector with positive/negative peaks around northern summer. Furthermore, it is noted that IHFAC amplitudes are modulated by solar activity, superimposed with seasonal effects, with consistently higher amplitudes during the northern summer months. The dusk‐time IHFAC also shows a pattern modulated by seasons and solar cycles, with negative peaks around northern summer only during the low solar active years. The seasonal pattern of IHFAC shows a similar trend from April to September, where dawn/noon IHFAC is south/north directed, and for the remaining months, both are northward directed. The dusk‐side IHFAC is mostly south‐directed irrespective of the season. Moreover, it is demonstrated that the seasonal pattern of dawn and noon‐time IHFAC amplitudes show a strong to moderate correlation with amplitudes of Sq asymmetries between two hemispheres, but dusk‐time IHFAC does not follow this trend. The IHFAC directions at TRD follow the Fukushima model for May to September during the dawn‐noon sector for 70%–95% of the days and less than 50% of the days for remaining months. The noon‐dusk sector shows Fukushima model‐type polarity for ∼60% of days in June–July and less than 50% for remaining months. The global analysis of IHFAC, using monthly averages of hourly values from eight observatories spanning Asia, Africa, and America, reveals spatial differences in amplitude and directions. The directions of noon‐time IHFAC in the Indian‐East Asian and East‐African sectors follow similar trends, and the amplitude variations of noon‐time IHFAC can be explained by DE‐3 tidal effects. The IHFAC from the South American and West African sectors show intense southward and northward currents compared to other sites, indicating the influence of the South Atlantic Anomaly (SAA). Plain Language Summary: IHFAC features have been identified in the Indian sector using long‐term geomagnetic data. The seasonal and solar cycle effects on IHFAC have been evaluated. Further attempts have been made to relate the observed seasonal pattern of IHFAC amplitudes with low and mid‐latitude Sq asymmetries between the two hemispheres, using Sq from low and mid‐latitude sites of both hemispheres of the Indian sector. It is noted that strong IHFAC in AUG‐SEP could be caused by Sq asymmetry in the low latitude sites. The study also tried to look at the IHFAC pattern around the globe using data from different sectors, and significant variations were observed and discussed. Key Points: Seasonal variation and solar activity dependence of IHFAC in the Indian sector is studied using long ‐term dataThe amplitude variations of dawn and noon time IHFAC have been connected to Sq asymmetry from low‐mid latitudes in the Indian sectorSpatial variations in IHFAC pattern are reported from American, African, Indian, East Asian sectors [ABSTRACT FROM AUTHOR]

Radio frequency fingerprint identification (RFFI) is a promising technique for smartphone identification. However, we find that the temperature of the RF front end in smartphones can significantly impact the RF features, including the carrier frequency offset (CFO) and statistical RF features. The unstable RF features caused by temperature changes can negatively affect the performance of state-of-the-art RFFI approaches. To this end, we propose the RF-TESI solution for smartphone identification under temperature variation. First, we construct a dataset by extracting temperature and RF features. In the dataset, the extracted temperature values constitute a set of temperature values and each registered temperature value corresponds to a group of RF features. Next, we evaluate the distinctiveness of RF features across smartphones to select the most suitable RF fingerprint. Then, we train multiple random forest models, each tagged with a registered temperature. In addition, because there are still many temperatures out of the temperature set, we design an RF fingerprint estimation method to estimate RF fingerprints at unregistered temperatures. Finally, the experiments show RF-TESI demonstrates satisfactory performance under different scenarios, taking into account variations in temperature, time and position. Besides, our proposed approach is better than all state-of-the-art approaches in smartphone identification. [ABSTRACT FROM AUTHOR]

We consider the asymptotic behaviour of a family of unidimensional lattice fermion models, which are in exact correspondence with certain probability laws on partitions and on unitary matrices. These models exhibit limit shapes, and in the case where the bulk of these shapes are described by analytic functions, the fluctuations around their interfaces have been shown to follow a universal Tracy–Widom distribution or its higher-order analogue. Non-differentiable bulk limit shape functions arise when a gap appears in some quantum numbers of the model, in other words when the Fermi sea is split. We show that split Fermi seas give rise to new interface fluctuations, governed by integer powers of universal distributions. This breakdown in universality is analogous to the behaviour of a random Hermitian matrix when the support of its limiting eigenvalue distribution has multiple cuts, with oscillations appearing in the limit of the two-point correlation function. We show that when the Fermi sea is split in the lattice fermion model, there are multiple cuts in the eigenvalue support of the corresponding unitary matrix model. [ABSTRACT FROM AUTHOR]

It is shown that the velocity fluctuation spectra measured using a hot wire in the potential flow region of the near field of a turbulent jet with a coflow can be converted into pressure fluctuation spectra. The proposed conversion method is based on the fact that the structure of instability waves, which make a decisive contribution to jet near-field fluctuations, resembles homogeneous one-dimensional waves, which makes it possible to locally link pressure fluctuations and the fluctuations of the streamwise velocity component measured by a hot wire. [ABSTRACT FROM AUTHOR]

To address the impact of wind-power fluctuations on the stability of power systems, we propose a comprehensive approach that integrates multiple strategies and methods to enhance the efficiency and reliability of a system. First, we employ a strategy that restricts long- and short-term power output deviations to smoothen wind power fluctuations in real time. Second, we adopt the sliding window instantaneous complete ensemble empirical mode decomposition with adaptive noise (SW-ICEEMDAN) strategy to achieve real-time decomposition of the energy storage power, facilitating internal power distribution within the hybrid energy storage system. Finally, we introduce a rule-based multi-fuzzy control strategy for the secondary adjustment of the initial power allocation commands for different energy storage components. Through simulation validation, we demonstrate that the proposed comprehensive control strategy can smoothen wind power fluctuations in real time and decompose energy storage power. Compared with traditional empirical mode decomposition (EMD), ensemble empirical mode decomposition (EEMD), and complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) decomposition strategies, the configuration of the energy storage system under the SW-ICEEMDAN control strategy is more optimal. Additionally, the state-of-charge of energy storage components fluctuates within a reasonable range, enhancing the stability of the power system and ensuring the secure operation of the energy storage system. [ABSTRACT FROM AUTHOR]

We investigate the effects of boost invariance breaking on the isotropization of pressure in the glasma, using a 3+1D glasma simulation. The breaking is attributed to spatial fluctuations in the classical color charge density along the collision axis. We present numerical results for pressure and energy density at mid-rapidity and across a wider rapidity region. It is found that, despite varying longitudinal correlation lengths, the behaviors of the pressure isotropizations are qualitatively similar. The numerical results suggest that, in the initial stage, longitudinal color electromagnetic fields develop, similar to those in the boost invariant glasma. Subsequently, these fields evolve into a dilute glasma, expanding longitudinally in a manner akin to a dilute gas. We also show that the energy density at mid-rapidity exhibits a 1 / τ decay in the dilute glasma stage. [ABSTRACT FROM AUTHOR]

Biochemical oscillations, regulating the timing of life processes, need to consume energy to achieve good performance on crucial functions, such as high accuracy of the phase period and high sensitivity to external signals. However, it is a great challenge to precisely estimate the energy dissipation in such systems. Here, based on the stochastic normal form theory, we calculate the Pearson correlation coefficient between the oscillatory amplitude and phase, and a trade-off relation between transport efficiency and phase sensitivity can then be derived, which serves as a tighter form than the estimator resulting from the conventional thermodynamic uncertainty relation. Our findings demonstrate that a more precise energy dissipation estimation can be obtained by enhancing the sensitivity of the biochemical oscillations. Moreover, the internal noise and amplitude power effects have also been discovered. [ABSTRACT FROM AUTHOR]

Kirkwood–Buff integrals (KBIs) connect the microscopic structure and thermodynamic properties of liquid solutions. KBIs are defined in the grand canonical ensemble and evaluated by assuming the thermodynamic limit (TL). In order to reconcile analytical and numerical approaches, finite-size KBIs have been proposed in the literature, resulting in two strategies to obtain their TL values from computer simulations. (i) The spatial block analysis method in which the simulation box is divided into subdomains of volume V to compute density fluctuations. (ii) A direct integration method where a corrected radial distribution function and a kernel that accounts for the geometry of the integration subvolumes are combined to obtain KBI as a function of V. In this work, we propose a method that connects both strategies into a single framework. We start from the definition of finite-size KBI, including the integration subdomain and an asymptotic correction to the radial distribution function, and solve them in Fourier space where periodic boundary conditions are trivially introduced. The limit q → 0, equivalent to the value of the KBI in the TL, is obtained via the spatial block-analysis method. When compared to the latter, our approach gives nearly identical results for all values of V. Moreover, all finite-size effect contributions (ensemble, finite-integration domains, and periodic boundary conditions) are easily identifiable in the calculation. This feature allows us to analyze finite-size effects independently and extrapolates the results of a single simulation to different box sizes. To validate our approach, we investigate prototypical systems, including SPC/E water and aqueous urea mixtures. [ABSTRACT FROM AUTHOR]

The appearance of spontaneous polarization in CuInP2S6 ferrielectrics is related to the second order Jahn-Teller effect for copper cations located in a double-well local potential, the stereoactivity of indium cations located in a three-well local potential, as well as the valence fluctuations of phosphorus cations. The paraelectric to ferrielectric phase transition is primarily determined by the coupling of indium cations with their surroundings. This transition can be analyzed using the mixed Ising model with spins S = 1/2 and S = 1. The spectrum of pseudospin fluctuations at different temperatures was calculated using a mean-field approach for a set of quantum anharmonic oscillators. The results were then compared with Raman spectroscopy data for CuInP2S6 crystal. The analysis indicates that the lattice anharmonicity below 150 K, is mainly determined by the indium sublattice, leading to the coexistence of the glassy state and ferrielectric phase. Above 150 K, the anharmonicity of the copper sublattice activates the ionic conductivity and results in the existence of a long-ranged fluctuated cluster of spontaneous polarization in a temperature interval of the paraelectric phase above TC. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effect of human heart-rate synchronization with variations in the geomagnetic field (GMF) ("biogeophysical synchronization effect"). We analyzed 403 electrocardiogram (ECG) recordings of 100 or 120 min that were obtained in 2012–2023 from two middle-aged female volunteers in good health. The minute-value series of the GMF vector from the INTERMAGNET network was used. Each ECG recording was individually examined using cross-correlation and wavelet analysis. The findings from two separate experimental sets (306 recordings from Volunteer A and 97 from Volunteer B) displayed notable similarity in all aspects analyzed: (1) For both participants, the biogeophysical synchronization effect is observed in 40–53% of the recordings as a statistically significant (p < 0.0045) correlation between minute heart-rate (HR) time-series values and at least one of the horizontal components of the GMF, with a time shift between values of [−5, +5] min. (2) Wavelet analysis indicates that the spectra of the HR series and at least one GMF component exhibit similarity in 58–61% of cases. (3) The synchronization is most evident within the period range between 8–13 min. The probability of the synchronization effect manifestation was independent of the geomagnetic activity (GMA) level, which was recorded during the observations. [ABSTRACT FROM AUTHOR]

We show how averages of exponential functions of path-dependent quantities, such as those of Work Fluctuation Theorems, detect phase transitions in deterministic and stochastic systems. State space truncation—the restriction of the observations to a subset of state space with prescribed probability—is introduced to obtain that result. Two stochastic processes undergoing first-order phase transitions are analyzed both analytically and numerically: a variant of the Ehrenfest urn model and the 2D Ising model subject to a magnetic field. In the presence of phase transitions, we prove that even minimal state space truncation makes averages of exponentials of path-dependent variables sensibly deviate from full state space values. Specifically, in the case of discontinuous phase transitions, this approach is strikingly effective in locating the transition value of the control parameter. As this approach works even with variables different from those of fluctuation theorems, it provides a new recipe to identify order parameters in the study of non-equilibrium phase transitions, profiting from the often incomplete statistics that are available. [ABSTRACT FROM AUTHOR]

It has been hypothesized that dark matter is comprised of ultra-light bosons whose collective phenomena can be described as a scalar field undergoing coherent oscillations. Examples include axion and fuzzy dark matter models. In this ultra-light dark matter (ULDM) scenario, the harmonic variation in the field's energy–momentum tensor sources an oscillating component of the gravitational potential that we show can resonantly excite stellar oscillations. A mathematical framework for predicting the amplitude of these oscillations is developed, which reveals that ULDM predominantly excites p-modes of degree l  = 1. An investigation of resonantly excited solar oscillations is presented, from which we conclude that dark matter induced oscillations of the Sun are likely undetectable. We discuss prospects for constraining ULDM using other stellar objects. [ABSTRACT FROM AUTHOR]

We consider the dynamics of a collection of n > 1 populations in which each population has its own rate of growth or decay, fixed in continuous time, and migrants may flow from one population to another over a fixed network, at a rate, fixed over time, times the size of the sending population. This model is represented by an ordinary linear differential equation of dimension n with constant coefficients arrayed in an essentially nonnegative matrix. This paper identifies conditions on the parameters of the model (specifically, conditions on the eigenvalues and eigenvectors) under which the variance of the n population sizes at a given time is asymptotically (as time increases) proportional to a power of the mean of the population sizes at that given time. A power-law variance function is known in ecology as Taylor's Law and in physics as fluctuation scaling. Among other results, we show that Taylor's Law holds asymptotically, with variance asymptotically proportional to the mean squared, on an open dense subset of the class of models considered here. [ABSTRACT FROM AUTHOR]