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Purpose: Transmeridian travel is common for elite athletes participating in competitions and training. However, this travel can lead to circadian misalignment wherein the internal biological clock becomes desynchronized with the light–dark cycle of the new environment, resulting in performance decrement and potential negative health consequences. Existing literature extensively discusses recommendations for managing jet lag, predominantly emphasizing light-based interventions to synchronize the internal clock with the anticipated time at the destination. Nevertheless, visually impaired (VI) athletes may lack photoreceptiveness, diminishing or nullifying the effectiveness of this therapy. Consequently, this invited commentary explores alternative strategies for addressing jet lag in VI athletes. Conclusions: VI athletes with light perception but reduced visual acuity or visual fields may still benefit from light interventions in managing jet lag. However, VI athletes lacking a conscious perception of light should rely on gradual shifts in behavioral factors, such as meal timing and exercise, to facilitate the entrainment of circadian rhythms to the destination time. Furthermore, interventions like melatonin supplementation may prove useful during and after travel. In addition, it is recommended that athlete guides adopt phase-forward or phase-back approaches to synchronize with the athlete, aiding in jet-lag management and optimizing performance. [ABSTRACT FROM AUTHOR]

Bolt loosening in bolted lap-joint connections can result in catastrophic failures in industrial settings. Therefore, it is crucial to investigate these connections thoroughly and implement preventative measures. However, examining such connections requires considering multiple influencing parameters. In this study, numerical simulations were conducted using three-dimensional finite element analysis in Abaqus software to evaluate these parameters in detail. The study employed a guided wave-based structural health monitoring approach and a precise ultrasonic-guided Lamb wave propagation method. Time signals were analyzed using phase shift and transmission coefficient (TC) factors as suitable indicators. Additionally, the S0 mode of the captured waves provided a highly informative wave packet for analysis due to its specific order. Initially, various simulations were carried out to determine the optimal length of the overlapping region that would result in the most effective transmission of waves. Increasing the bolt torque and the contact friction coefficient between the two plates in the overlapping region reduces the time for waves to reach the sensor and increases the TC of the passing waves. However, the saturation state does not cause any change in the received signals. Increasing the bolt torque is more effective in facilitating wave transmission through the connections than increasing the contact friction coefficient. Furthermore, variations in excitation voltage do not affect the arrival time or TC of the waves. The continuous wavelet transformation enabled a more detailed time-frequency analysis. The results demonstrate that changes in bolt torque do not impact the wave frequencies reaching the sensors, making the frequency insensitive to bolt loosening. Ultimately, the numerical simulation results were validated through experiments on a table-top laboratory sample. This research enhances researchers' understanding of monitoring the health status of bolted lap-joint connections by investigating the impact of various parameters on guided Lamb wave transmission through these connections. [ABSTRACT FROM AUTHOR]

Abstract\nHIGHLIGHTSAs a special branch of metamaterials characterized by phase discontinuity, elastic metasurfaces have presented extraordinary capacity for elastic wave manipulation. This class of metamaterials has received extensive attention in recent years. In this paper, a subwavelength elastic metasurface with locally resonant prisms is employed to steer the propagation of the A0 Lamb wave. Based on the dispersion curve and transmission ratio, we establish that the resonant feature of prisms is influenced by the diagonal ratio of cross section. By gradually tuning the diagonal ratio of prism cross section, the pattern of resonance modes and the mechanism of resonance superposition are clarified. In this regard, two different resonant modes can be superimposed at a certain frequency. A complete 2π phase shift that is crucial for redirecting wave propagation can therefore be realized. To have a broader working frequency range, the influence of prism height on the resonance superposed frequency and the effect of plate thickness on the incident flexural wave are explored. Based on the generalized Snell’s law, negative refraction is verified numerically through a metasurface assembled from unit cells with constant phase change. In addition, other wavefront modulations such as eccentric focusing, nonparaxial propagation are also demonstrated. This novel design introduces new degrees of freedom in many engineering applications such as seismic wave protection, structural health monitoring and energy harvesting.Proposing a novel subwavelength prismatic metasurface at mm-scale capable of operating in the kHz frequency range.Introducing an approach for altering the resonant mode frequency of building block.Establishing mechanism of resonant mode frequency variation and superposition.Realizing full phase span from 0 to 2π by superimposing of compression and bending modes.Demonstrating abnormal wavefront control for flexural wave by novel prismatic metasurfaces, such as negative refraction, eccentric focusing, parabolic and curvilinear wave trajectories. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim Location Time Period Major Taxa Studied Methods Results Main Conclusions Ecological state shifts that alter the structure and function of entire ecosystems are a concerning consequence of human impact. Yet, when, where and why discrete ecological states emerge remains difficult to predict and monitor, especially in high‐diversity systems. We sought to quantify state shifts and their drivers through space and time in the most ecologically complex marine ecosystem: tropical coral reefs.Worldwide.1987–2019.Coral reef communities.Using a global dataset of 3375 coral reef surveys, along with 13 time series datasets ranging between 1987 and 2019, we applied a novel double‐dichotomy approach to classify coral reefs into four simplified and discrete states based on the relative contributions of corals versus algae to benthic cover and small‐bodied versus large‐bodied fishes to fish standing stock. We then examined state shifts considering a range of spatial predictors and tested whether states have shifted directionally over time, and the nature of the most common transitions.We show that geographic, environmental and anthropogenic context fundamentally shapes coral reef states at the local scale, which explains disparities among case studies, and stakes out critical baseline expectations for regional management efforts. We also reveal clear multi‐decadal state shifts on coral reefs: over time, systems dominated by reef‐building corals and small‐bodied, planktivorous fishes tend to have been replaced with reefs characterised by algae and larger‐bodied fishes.Our results suggest a previously unrecognised transition from systems that harness external subsidies through small‐bodied consumers associated with structurally complex live corals, to herbivore‐dominated systems with stronger bottom‐up dynamics. Overall, the partitioning of complex reef ecosystems into a small suite of discrete ecological states suggests that spatial context‐dependency, shifting baselines and changes in reef functioning are crucial considerations for coral reef management in the 21st century. [ABSTRACT FROM AUTHOR]

At an altitude of 1000 - 2000 km in the Venusian upper ionospheric region, the plasma is composed of H + ions, O + ions, and solar wind (SW) protons with electrons distributed according to the kappa distribution. This research delves into the exploration of nonlinear solitary and periodic waves, including the behavior of two-soliton. The Reductive Perturbation Technique (RPT) is used to derive the Korteweg-de Vries (KdV) equation for studying these nonlinear waves. Subsequently, a travelling wave transformation is employed to establish a planar dynamical system for the obtained KdV equation. Phase portrait is drawn and the associated nonlinear waves are examined adjusting the values of the parameters temperature ratio, unperturbed number density ratios, spectral index and travelling wave speed. Two-soliton solution of the KdV equation is investigated using the Hirota's direct approach. The influence of parameters like the spectral index, unperturbed number density ratios, and temperature ratio on the two-soliton is demonstrated, including the change in the phase shift. The findings from this research provide valuable insights into the dynamics of two-soliton solutions and nonlinear waves in the upper ionosphere of Venus. [ABSTRACT FROM AUTHOR]

AbstractThe microwave free-space technique is an important method to characterize material properties in the scientific fields and actual applications. A microstrip patch antenna is a good radiating element to construct a compact, low-cost free-space setup. It is necessary to clarify the effects of different properties of radiating patch antenna. In this study, microwave attenuation and phase shift are measured with patch antennas with different radiated microwave power and gain. Both the experimental results of attenuation and phase shift show that a high gain of the radiating elements is helpful to measure the microwave parameters in the free-space method accurately, while improving radiating power has less effect. [ABSTRACT FROM AUTHOR]

In chronobiology, shifting light/dark cycles is a common method to disrupt circadian rhythms. While the direction and magnitude of a phase shift (e.g., +6 denoting a 6‐h advanced shift) dictate the temporal change before and after the shift, little attention has been paid to the duration and relative proportion of daytime and nighttime during the shift, leading to a critical, unexamined variable in circadian research. In this study, we introduce the concepts of "L‐shift" (longer light phase on the shift day) and "D‐shift" (longer dark phase), and investigate how these variations impact the adaptability of mice to jet lag. By examining multiple phase shifts (12L vs. 12D, +6L vs. +6D, −6L vs. −6D), we demonstrate that L‐shifts not only facilitate faster adaptation but also significantly reduce the severity of sepsis in a jet lag‐sensitive lipopolysaccharide‐induced sepsis model. Further investigations with additional phase shifts at 1‐h intervals (+8 to +11) reinforced the enhanced fitness of mice under L‐shifts. Mechanistically, L‐shifts were found to increase sleep duration, thereby improving circadian entrainment, with sleep deprivation nullifying the adaptability differences between lighting protocols. These findings underscore a previously unrecognized factor in circadian biology and suggest that optimizing lighting protocols could profoundly improve adaptability to circadian disruptions. This research opens new avenues for enhancing therapeutic strategies and refining experimental designs in the field of chronobiology. [ABSTRACT FROM AUTHOR]

Intense field dielectrics (IFD) are widely used in the air purification industry. DC power supplies must be designed to provide a high voltage for IFD products. Therefore, this paper introduces a compact 10 kV high-voltage DC power supply tailored for IFD air purification. It employees a novel controller, which is a fusion of a fixed-frequency PWM-based sliding-mode controller and a phase-shift full-bridge configuration. The superiority of the proposed DC power supply topology is demonstrated. Rigorous simulation analysis employing MATLAB/Simulink shows that the robustness and stability of the new controller are much better than fixed-frequency PWM-based sliding-mode controllers. Subsequently, a high-voltage DC power prototype is fabricated, followed by comprehensive experimental validation. Test results underscore the stability of the DC power supply under normal operating conditions. Notably, when the controller adopts a linear PI configuration, the DC voltage output ripple is contained within a stringent threshold of ≤ 0.4%. Moreover, in the presence of AC power system oscillations, the novel controller showcases its ability to achieve a heightened response speed, which contributes to the robustness of the DC power supply. [ABSTRACT FROM AUTHOR]

ABSTRACT This paper proposes a novel control method to achieve the true unity power factor for a single‐phase boost rectifier. Firstly, the phase difference between the voltage and current on the AC side is calculated by the heterodyne method. Secondly, this phase difference is fed into an integral regulator to get a phase shift angle. Finally, by using the heterodyne method once again, the AC side current is phase‐shifted and used as the modulation signal for the single‐phase full bridge rectifier circuit and ultimately yields a unity power factor. The experimental results verify the effectiveness and feasibility of this strategy. [ABSTRACT FROM AUTHOR]

This study focuses on a method for accurately determining the phase shift between two harmonic signals. The proposed technique compares the waveform of the combined signal, which is obtained by applying a two-phase interpolation transformation, with a set of predefined reference functions. This study aims to develop a method for accurately measuring the phase shift between two harmonic signals to reduce the measurement errors caused by phase asymmetry in signal transmission channels and minimize the costs associated with parameter control. The sources of error in the proposed measurement method are identified and addressed. The task involves setting up the measurement objective to determine the phase shift between two harmonic signals. This section presents the analyses of known methods for measuring phase shifts using of analog-to-digital conversion. The next step involves selecting indicators and criteria to determine how closely the investigated signal matches the reference function. Then, we propose the synthesis of an algorithm to find the extremum of the sum of squares deviations for the set of reference functions and the investigated signal, relying on the golden ratio method. Finally, the paper will analyze possible sources of error that could affect the measurement outcome. The methods used are the following: methodology for conducting digital signal processing and measuring error estimation, numerical methods for extremum search, and methodology for single-factor experiments. The following results were obtained. A proposed compensation method for measuring phase shift is based on comparing the shape of the normalized signal, which is obtained as a result of the summation of harmonic signals after their semiperiodical transformation, with a set of normalized reference functions synthesized by computational means. A list of measurement and auxiliary operations, which should be ideally conducted to implement this measurement method, has been determined. An analysis of the components of measurement errors was conducted. Conclusions. The scientific novelty of the obtained results lies in the following: a method for measuring the phase shift of a signal has been developed, which, in our opinion, should be classified as a compensatory measurement method. This will significantly reduce the error component caused by the phase asymmetry of signal transmission channels and reduce the costs of controlling parameters (up to 10%) without decreasing the quality of control; a list of the measuring and auxiliary operations necessary for the implementation of the proposed measurement method has been identified; sources of errors have been determined.

This article considers the problem of aeroelastic oscillations in the channel wall having a suspension with hardening cubic nonlinearity, which were induced by the vibration of the channel foundation. The narrow flat channel formed by two parallel rigid walls and filled with pulsating viscous gas was examined. The bottom wall was stationary, while the opposite one had a nonlinear elastic suspension. The aeroelasticity problem was formulated for the isothermal state of the gas and channel walls. Considering the narrowness of the channel, the equations of dynamics were derived for a thin layer of the viscous gas, and the asymptotic analysis of the problem was performed by the perturbation method. Using the method of iterations, the law of viscous gas pressure distribution in the channel was determined, and the equation of aeroelastic oscillations in the channel wall was obtained as a generalization of the Duffing equation. This equation was solved by the harmonic balance method. The primary nonlinear aeroelastic response of the channel wall and the nonlinear phase shift were expressed as implicit functions. These characteristics were studied numerically to evaluate the influence of the nonlinear elastic suspension of the channel wall and the viscous gas inertia and compressibility on the nonlinear oscillations in the channel wall.

This paper investigates the formation of vibration fields in a mechatronic setup driven by dual induction motors, relying on the controlled synchronization of unbalanced rotors. The proposed algorithm enables precise control over rotor speeds and phase shifts. Experimental results from a multi-resonance vibration laboratory setup demonstrate this approach's ability to form the vibration fields. The ability to control these fields is crucial for applications such as vibratory transportation and the mixing of bulk materials. The results obtained can ensure a diverse picture of the complex trajectories of motion for various points of the platform, primarily in the screens, making various useful effects for vibration technologies. Additionally, the practical value of this research is that in the case of double synchronous mode the ordinate of the lower point of the trajectory is lower than in the case of single synchronous mode, which improves the efficiency of unloading and prevents congestion formation. The experimental data highlight the practical advantages and potential improvements in efficiency and reliability offered by this method. [ABSTRACT FROM AUTHOR]

This article presents an experimental investigation on failure strengths and mechanical responses of transversely isotropic slates under the compressive differential cyclic loading. The tests involve five bedding orientations (0°, 30°, 45°, 60°, 90°) and two loading modes. The tests aim to investigate the coupled influence of the distinct loading/unloading rates and bedding orientation on the anisotropic characteristics, incl. the deformability, energy dissipation, damping ratio, phase shift and failure patterns. The results show that both loading modes and bedding angles have impacts on the mechanical responses of slates. Specifically, it is observed that rapid loading and slow unloading result in a higher growth rate of peak/residual strain versus cycle number as well as more intensive energy dissipation, and correspond to more significant phase shift. The influence of bedding angles on energy dissipation and strain is less pronounced compared to the effects of differential cyclic loading. The nuclear magnetic resonance was used to analyze the T2 spectra of the failed samples with different bedding angles. Highlights : Rapid loading and slow unloading tend to intensify the phase shift at peak stress, while their effect on minimum stress remains unpronounced. Rapid loading and slow unloading tend to cause larger energy dissipation under different bedding angles. The modified Jaeger's plane of weakness model can well capture rock strengths across varying bedding angles when subjected to differential cyclic loading. [ABSTRACT FROM AUTHOR]

Overtaking collision of unidirectional dust acoustic waves in the Thomas-Fermi dense magnetoplasma has been investigated. The system consists of classical negatively charged dust particles with degenerate electrons and ions. Nonlinear Korteweg-de Vries (KdV) equation that characterizing the dust acoustic solitons in such a plasma model is derived. The system admits only rarefactive solitary waves. Hirota's bilinear method is used to investigate the overtaking collision of two and three-soliton solutions. The exchange of energies due to the overtaking collisions is affected by physical parameters such as the electron equilibrium density, the dust temperature, and the obliquity angle. This causes the solitons behavior to be alternated. The amplitude, and width increase as the dust temperature and electron density decrease or when the dust density increases. The magnetic field affects only the soliton's width. The phase shifts are also affected by the system parameters. The current study is an attempt to illuminate the properties of N-soliton in Thomas-Fermi dense magnetoplasma that are applicable in compact astrophysical objects such as white dwarfs and high-intensity laser-solid matter interaction experiments. [ABSTRACT FROM AUTHOR]

This contribution reviews the role of inbred and transgenic mouse strains for deciphering the mammalian melatoninergic and circadian system. It focusses on the pineal organ as melatonin factory and two major targets of the melatoninergic system, the suprachiasmatic nuclei (SCN) and the hypophysial pars tuberalis (PT). Mammalian pinealocytes sharing molecular characteristics with true pineal and retinal photoreceptors synthesize and secrete melatonin into the blood and cerebrospinal fluid night by night. Notably, neuron‐like connections exist between the deep pinealocytes and the habenular/pretectal region suggesting direct pineal‐brain communication. Control of melatonin biosynthesis in rodents involves transcriptional regulation including phosphorylation of CREB and upregulation of mPer1. In the SCN, melatonin acts upon MT1 and MT2 receptors. Melatonin is not necessary to maintain the rhythm of the SCN molecular clockwork, but it has distinct effects on the synchronization of the circadian rhythm by light, facilitates re‐entrainment of the circadian system to phase advances in the level of the SCN molecular clockwork by acting upon MT2 receptors and plays a stabilizing role in the circadian system as evidenced from locomotor activity recordings. While the effects in the SCN are subtle, melatonin is essential for PT functions. Via the MT1 receptor it drives the PT‐intrinsic molecular clockwork and the retrograde and anterograde output pathways controlling seasonal rhythmicity. Although inbred and transgenic mice do not show seasonal reproduction, the pathways from the PT are fully intact if the animals are melatonin proficient. Thus, only melatonin‐proficient strains are suited to investigate the circadian and melatoninergic systems. [ABSTRACT FROM AUTHOR]

The high mobility of unmanned aerial vehicles (UAVs) enables them to improve system throughput by establishing line-of-sight (LoS) links. Nevertheless, in urban environments, these LoS links can be disrupted by complex urban structures, leading to potential interference issues. Reconfigurable intelligent surfaces (RIS) provide an innovative approach to enhance communication performance by intelligently reflecting incident signals. Recent studies suggest that utilizing multi-antenna transmission can increase system efficiency, while single-antenna transmission may be more prone to interference. To address these challenges, this article introduces a RIS-assisted multiple-input single-output (MISO) UAV communication system. Our objective is to optimize the minimum user rate, thereby guaranteeing equitable communication for all users. Nevertheless, the non-convexity inherent in this optimization problem complicates the pursuit of a direct solution. Hence, we decompose the problem into four subproblems: user scheduling optimization, RIS phase-shift optimization, UAV trajectory optimization, and UAV transmit beamforming optimization. To obtain suboptimal solutions, we have developed an alternating iterative optimization algorithm for addressing the four subproblems. Numerical results demonstrate that our algorithm effectively boosts the minimum user rate of the entire system. [ABSTRACT FROM AUTHOR]

Ecological theory predicts that kelp forests structured by trophic cascades should experience recovery and persistence of their foundation species when herbivores become rare. Yet, climate change may be altering the outcomes of top‐down forcing in kelp forests, especially those located in regions that have rapidly warmed in recent decades, such as the Gulf of Maine. Here, using data collected annually from 30+ sites spanning >350 km of coastline, we explored the dynamics of Maine's kelp forests in the ~20 years after a fishery‐induced elimination of sea urchin herbivores. Although forests (Saccharina latissima and Laminaria digitata) had broadly returned to Maine in the late 20th century, we found that forests in northeast Maine have since experienced slow but significant declines in kelp, and forest persistence in the northeast was juxtaposed by a rapid, widespread collapse in the southwest. Forests collapsed in the southwest apparently because ocean warming has—directly and indirectly—made this area inhospitable to kelp. Indeed, when modeling drivers of change using causal techniques from econometrics, we discovered that unusually high summer seawater temperatures the year prior, unusually high spring seawater temperatures, and high sea urchin densities each negatively impacted kelp abundance. Furthermore, the relative power and absolute impact of these drivers varied geographically. Our findings reveal that ocean warming is redefining the outcomes of top‐down forcing in this system, whereby herbivore removal no longer predictably leads to a sustained dominance of foundational kelps but instead has led to a waning dominance (northeast) or the rise of a novel phase state defined by "turf" algae (southwest). Such findings indicate that limiting climate change and managing for low herbivore abundances will be essential for preventing further loss of the vast forests that still exist in northeast Maine. They also more broadly highlight that climate change is "rewriting the rules" of nature, and thus that ecological theory and practice must be revised to account for shifting species and processes. [ABSTRACT FROM AUTHOR]

Local and global ecological stressors are leading to increased documentation of phase shifts in coral reefs from healthy stony corals to macrophytes. In more rare cases, phase shifts result in sponge, zoantharian or other dominant species. In Ulithi Atoll, Federated States of Micronesia, we have documented an unusual phase shift from reefs with a diverse stony coral assemblage to reefs dominated by a single species of stony coral: Montipora sp.—a coral-to-coral phase shift. This monospecific type of reef lowers fish diversity and biomass, impacting both ecological integrity, and livelihoods of reef-dependent human communities. In this study, we used a genomic approach to characterize such a reef. We assembled a de-novo reference genome and used RAD seq data with thousands of SNPs to determine if different reefs result from sexual or asexual reproduction, if weedy Montipora fragments are transported between islands by human activities, and if there is evidence of natural selection on specific genotypes, thus favoring spreading success. We found that sexual reproduction is predominant in the focal species, that there is no evidence of human-mediated spread, and that some genomic regions might be under selection. While such results eliminate a number of spreading hypotheses, more precise dispersal maps will be important to determine the tempo and mode of 'invasion' of Montipora in Ulithi Atoll. This study shows that selection and adaptation may be contributing to the success of a stony coral (e.g., Phase shift). While a stony coral may be successful in a disturbed environment, it does not necessarily provide the type of habitat that is conducive to high fish biomass and coral diversity. These results serve as a cautionary tale for restoration efforts that focus on single species coral resilience rather than ecosystem function. [ABSTRACT FROM AUTHOR]

With the dramatic increase in mobile users and wireless devices accessing the network, the performance of 5G wireless communication systems is severely challenged. Reconfigurable Intelligent Surface (RIS) has received much attention as one of the promising technologies for 6G due to its ease of deployment, low power consumption, and low price. This study aims to improve accuracy, reliability, and the capacity to estimate channel characteristics between transmitter and receiver. However, this is practically challenging for the following reasons. Due to the lack of active components for baseband signal processing, low-cost passive RIS elements can only reflect incident signals but without the capability to transmit/receive pilot signals for channel estimation as active transceivers in conventional wireless communication systems. This study presents different channel estimation methods for RIS-MIMO systems that use deep learning techniques. [ABSTRACT FROM AUTHOR]

The forced vibration of rectangular thin plate with a pair of edges simply supported and another pair of edges clamped mounted on the fractional standard solid foundation under the standing and moving loads is studied in this paper. Compared with the traditional integer-order viscoelastic foundation model, the fractional-order viscoelastic foundation model can describe the complicated historical dependent mechanical behavior of actual foundation more accurately. Based on the proposed fractional standard solid foundation model, the complex elastic modulus of the stress-strain constitutive relation is derived. Numerical examples verify that the fractional standard solid model can more accurately fit the experimental data. On this basis, the complex natural frequency and mode shape function in free vibration and the analytic response in forced vibration are solved. The complex natural frequency, the response lag and the critical speed or the resonant speed of the applied moving loads are mainly investigated. The numerical examples are provided and the effects of the fractional-order viscoelastic foundation and the speed and accelerations of moving load are discussed. [ABSTRACT FROM AUTHOR]

Dynamics of nonlinear ion-acoustic waves (IAWs) are studied for Venus' lower atmosphere at an altitude of 200 − 1000 km. Two-soliton, nonlinear solitary and periodic waves in a three-component plasma consisting of H + and O + ions with kappa distributed electrons are studied. Using the reductive perturbation technique (RPT), the Korteweg-de Vries (KdV) equation is derived and a Planar dynamical system is formed for the KdV equation using a travelling wave transformation. A phase portrait is drawn to analyze nonlinear wave behaviors by adjusting the parameters κ (spectral index), γ (unperturbed number density ratio), and V (travelling wave speed). Increasing values of κ amplify amplitudes for solitary and periodic waves, narrow down the width of the solitary wave, and broaden the width of the periodic wave. Increasing value of γ boosts amplitude of the solitary wave with unchanged width, while amplitude of the nonlinear periodic wave decreases and width widens. Increasing value of V enhances amplitudes and reduces widths for both solitary and periodic waves. Two-soliton solutions for the KdV equation are studied using the Hirota direct method. Increasing value of γ reduces amplitude of the soliton without affecting the width and increasing value of κ reduces width of the soliton. Phase shift for two-soliton is also shown and found that for different values of κ , the phase shift increases on increasing value of γ . The findings of our result aid in understanding the dynamics of nonlinear waves and two-soliton solutions in Venus' lower ionosphere. [ABSTRACT FROM AUTHOR]

Chaotic dynamics have been evidenced in experimental data and numerical simulations ranging from the most straightforward individual neurons to the more complex neural groups. Nevertheless, whether chaotic behavior significantly contributes to the emergence of phase shift and spontaneous switchings between transient synchrony activities is subtle and remains elusive. We investigated the emergence of spontaneous transient synchrony activities and self-induced switchings in an excitatory-inhibitory network. We demonstrate that the dynamic nature of isolated neurons plays an essential role in the emergence of chaotic behavior, thereby affecting spontaneous transient synchrony and types of phase shift. We also show that the neural network of the cells with chaotic characteristics after synaptic interactions exhibits a broader range of excitatory transient synchronous dynamics. Our results offer several possibilities for explaining sensory perception and brain disease observed in experiments. [ABSTRACT FROM AUTHOR]

The intense human pressures in the Anthropocene epoch are causing an alarming decline in marine coastal ecosystems and an unprecedented loss of biodiversity. This situation underscores the urgency of making ecological restoration a global priority to recover degraded ecosystems. Meadows of the endemic Mediterranean seagrass Posidonia oceanica have lost more than half of their original extent in the last century, necessitating immediate conservation and management measures, supported by active restoration interventions. This paper explores new opportunities and provides specific recommendations to enhance restoration as a fundamental strategy for reversing the decline of P. oceanica ecosystems in the Mediterranean Sea. When a return to a historical pristine reference condition may not be feasible in the short term or desirable given current environmental conditions and uncertainty, transplanting the tolerant and fast-growing seagrass species Cymodocea nodosa could facilitate natural recolonization. This would occur through secondary ecological succession, benefiting the sensitive and slow-growing species P. oceanica. Future global and local efforts should primarily focus on proactive management to prevent further alterations by planning appropriate conservation measures in a timely manner to mitigate and reverse global changes. As a secondary step, restoration programs can be implemented with a focus on 'target-oriented' rather than 'reference-oriented' conditions, aiming to establish ecosystems capable of sustaining the future rather than replicating the historical environment. [ABSTRACT FROM AUTHOR]

DNA aptamers can bind specifically to biomolecules to modify their function, potentially making them ideal oligonucleotide therapeutics. Herein, we screened for DNA aptamer of melanopsin (OPN4), a blue-light photopigment in the retina, which plays a key role using light signals to reset the phase of circadian rhythms in the central clock. Firstly, 15 DNA aptamers of melanopsin (Melapts) were identified following eight rounds of Cell-SELEX using cells expressing melanopsin on the cell membrane. Subsequent functional analysis of each Melapt was performed in a fibroblast cell line stably expressing both Period2:ELuc and melanopsin by determining the degree to which they reset the phase of mammalian circadian rhythms in response to blue-light stimulation. Period2 rhythmic expression over a 24-h period was monitored in Period2:ELuc stable cell line fibroblasts expressing melanopsin. At subjective dawn, four Melapts were observed to advance phase by >1.5 h, while seven Melapts delayed phase by >2 h. Some Melapts caused a phase shift of approximately 2 h, even in the absence of photostimulation, presumably because Melapts can only partially affect input signaling for phase shift. Additionally, some Melaps were able to induce phase shifts in Per1::luc transgenic (Tg) mice, suggesting that these DNA aptamers may have the capacity to affect melanopsin in vivo. In summary, Melapts can successfully regulate the input signal and shifting phase (both phase advance and phase delay) of mammalian circadian rhythms in vitro and in vivo. [ABSTRACT FROM AUTHOR]

We explore the dynamic characteristics of positron acoustic multiple-solitons in an unmagnetized plasma containing mobile cold positrons, Kappa-distributed superthermal hot electrons and positrons, and stationary positive ions. This study investigates the overtaking collisional effects, various parametric impacts, and phase shifts in the electron–positron-ion (e-p-i) plasma. Through the reductive perturbation technique, we derived the Korteweg-de Vries (KdV) equation and the modified Korteweg-de Vries (mKdV) equation. The multiple-soliton solutions (MSS) are then obtained using the simplified Hirota method and Cole-Holf transformation. The investigation shows that the amplitudes and widths of multi-solitons decrease with the increasing hot positron concentration but increase with the increasing hot electron index parameter. The results are expected to help us understand the dynamics of waves propagation in the pulsar magnetosphere, the active galactic nuclei, the quasar's relativistic jet, the inner region of the accretion disk surrounding a black hole, etc. [ABSTRACT FROM AUTHOR]

Oxygen depletion is well recognized for its role in the degradation of tropical coral reefs. Extreme acute hypoxic events that lead to localized mass mortality and the formation of 'dead zones' (a region where few or no organisms can survive due to a lack of oxygen) are particularly concerning as they can result in wide-ranging losses of biodiversity, ecosystem productivity and functioning, economic prosperity, and wellbeing. In March of 2022, the annual coral spawning event at Bills Bay (Coral Bay, Ningaloo Reef, Western Australia) coincided with elevated seawater temperature, calm weather conditions and a flood tide resulting in coral spawn becoming trapped in Bills Bay. Immediately after, there was a mass fish kill, which is believed to have been caused by local eutrophication resulting in severe oxygen depletion. The impact the deoxygenation and thermal stress event had on benthic communities has not yet been quantified; hence, the principal aim of this study is to document the extent of change that occurred in the benthic communities before and after the 2022 coral spawning event over a spatial gradient from the nearshore to mid-reef. Percent coral cover in the Bay decreased from 55.62 ± 2.26% in 2016–2018 and 70.44 ± 5.24% in 2021 to 1.16 ± 0.51% in 2022. Over the same period, the percent cover of turf algae increased from 27.40 ± 2.00% in 2016–2018 and 24.66 ± 6.67% in 2021 to 78.80 ± 3.06% in 2022, indicating a dramatic phase shift occurred at Bills Bay. The abundance of healthy coral colonies recorded on replicated belt transects at nine sites declined from 3452 healthy individuals in 2018 to 153 individuals in 2022 and coral generic richness decreased by 84.61%, dropping from 26 genera in 2018 to 4 genera in 2022. Previously dominant genera such as Acropora,Montipora and Echinopora, were extirpated from survey sites. Isolated colonies of massive Porites spp. and encrusting Cyphastrea sp. survived the event and understanding the mechanisms underpinning their greater survivorship is an important area of future research. Long-term monitoring is recommended to track the community recovery process and improve our understanding of the longer-term implications of this acute mortality event on the ecological, socio-economic and cultural values of Ningaloo Reef. [ABSTRACT FROM AUTHOR]

This paper proposes the design and validation of a novel rate-dependent direct inverse Preisach model with input iteration (RDIPMII) dedicated to feedforward compensation of hysteresis nonlinearity in piezoelectric actuators (PEAs). Unlike existing similar works, the proposed RDIPMII avoids deriving the parameters of the inverse compensator from the hysteresis model, and could be directly employed as the inverse compensator. Furthermore, RDIPMII is capable of achieving rate-dependent inverse compensation while reducing the experimental burden in identifying models by the use of newly proposed data expression method (DEM). In addition, by integrating iterative learning control (ILC), RDIPMII accomplishes online input iteration to further suppress the hysteresis effect. The feasibility and efficiency of the presented scheme are demonstrated through experimental investigations conducted on a PEA. [ABSTRACT FROM AUTHOR]

Advanced sensing technologies and communication capabilities of Connected and Autonomous Vehicles (CAVs) empower them to capture the dynamics of surrounding vehicles, including speeds and positions of those behind, enabling judicious responsive maneuvers. The acquired dynamics information of vehicles spurred the development of various cooperative platoon controls, particularly designed to enhance platoon stability with reduced spacing for reliable roadway capacity increase. These controls leverage abundant information transmitted through various communication topologies. Despite these advancements, the impact of different vehicle dynamics information on platoon safety remains underexplored, as current research predominantly focuses on stability analysis. This knowledge gap highlights the critical need for further investigation into how diverse vehicle dynamics information influences platoon safety. To address this gap, this research introduces a novel framework based on the concept of phase shift, aiming to scrutinize the tradeoffs between the safety and stability of CAV platoons formed upon bidirectional information flow topology. Our investigation focuses on platoon controls built upon bidirectional information flow topologies using diverse dynamics information of vehicles. Our research findings emphasize that the integration of various types of information into CAV platoon controls does not universally yield benefits. Specifically, incorporating spacing information can enhance both platoon safety and string stability. In contrast, velocity difference information can improve either safety or string stability, but not both simultaneously. These findings offer valuable insights into the formulation of CAV platoon control principles built upon diverse communication topologies. This research contributes a nuanced understanding of the intricate interplay between safety and stability in CAV platoons, emphasizing the importance of information dynamics in shaping effective control strategies. [ABSTRACT FROM AUTHOR]

Phase shift plays a vital role in the analysis of interference and manipulation of polarization behavior in interferometric techniques. The Sagnac interferometer (SI) is initially studied due to its ability to withstand external environmental factors, including noise, temperature, and other interferences. However, the real impact of these factors is not demonstrated. To address this, comparative studies are conducted involving both mathematical theories, simulations, and physical experiments of Sagnac and Mach-Zehnder interferometers (MZI), both utilizing a phase shift. The purpose is to explore the SI advantages over the MZI in a series of experiments with both interferometers to validate the superior configuration. Numerical simulations of the total electric field are performed at the output of these interferometers. By adjusting the orientation of a half-wave plate from 45 and 135 degrees at a step of 90 degrees, the interference fringe pattern and respective signal are generated. These simulation parameters are then implemented experimentally, and the results from both approaches are carefully analyzed and compared. It is shown that the light reflection through the SI setup makes it more tolerant to noise compared to the MZI. Consequently, these results confirm that the image intensity and pixel level of the SI are higher than that of the MZI, potentially leading to greater brightness for the simplified image analysis. [ABSTRACT FROM AUTHOR]

Commitment scheme is a fundamental cryptographic primitive that serve as building blocks for many other two-party protocols. In this paper, we propose a novel quantum bit commitment scheme, which is secure and does not require quantum memory. Our scheme processes the quantum information using coherent states and unambiguous state discrimination (USD) measurements, which can be experimentally realized by linear optics and photon detectors. We ensure the unconditionally hiding and binding property by preventing both Alice and Bob from obtaining complete information about the commitment in committing stage, and eliminate the requirement for quantum memory by performing USD measurements and phase shifts immediately after receiving the coherent states. [ABSTRACT FROM AUTHOR]

The response of rock to dynamic loading is critical to the stability of underground engineering. This study experimentally investigated the mechanical responses of sandstone exposed to incremental and decremental frequency under compressive cyclic loading. The impact of loading frequency on amplitude of strain variation between the upper and lower bounds of cyclic stresses are revealed. The result shows that a higher frequency can incur a larger-amplitude variation of axial and volumetric strains between two bounds of cyclic stresses. The inelastic axial and radial strain ratios (defined in text) both exhibit good performance in early warning of rock failure. The cyclic loading stage (CLS) with the lowest inelastic strain ratio can be defined as the critical phase. This also applies to the evolution of secant modulus, the CLS with the peak secant modulus is used as the point to emit warning signals. The phase shift between stress–strain is frequency-dependent, a lower frequency results in a larger phase-shift. The evolution of damping ratio and dissipated energy ratio are almost frequency independent and both decrease with the ongoing of cycle. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: In recent years, interesting results have been obtained on the study of the nonlinear dynamics of translational, rotational and pendulum electromechanical systems. Most of these systems consider one-directional motions or coupling of one-directional motions. However, for some applications, actuators can move over different places on a surface or plane. Purpose: The purpose of this work is to study the nonlinear dynamics of a mass moving over a plane when it is subjected to perpendicular springs and perpendicular forces created two periodically excited electromagnets with phase shift. Methods: After the derivation of the equations of motions using mechanics laws and interaction forces created by electromagnets, the harmonic balance method and the fourth-order Runge-Kutta method are used to obtain mathematically and numerically the dynamical states of the system. Results: It is found that a bidimensional periodic motion takes place along the oblique line with slope depending on the phase shift. The frequency-response curves of the periodic motion show resonance, antiresonance and hysteresis. The bifurcation diagrams versus the amplitude of the excitations and the phase shift show that the dynamical states can be periodic or chaotic. The transition from the periodic states to chaos is either through successive period-doublings or abrupt. Conclusion: In this work, the nonlinear dynamics of a mass subjected to the action of perpendicular springs and perpendicular periodic forces with phase shift has been analyzed. It has been found that the mass can exhibit several dynamical states in a plane including chaos characterized by the random distribution of the positions occupied by the mass in the bidimensional space. [ABSTRACT FROM AUTHOR]

Context shapes our perception of facial expressions during everyday social interactions. We interpret a person's face in a hostile situation negatively and judge the same face under pleasant circumstances positively. Critical to our adaptive fitness, context provides situation-specific framing to resolve ambiguity and guide our interpersonal behavior. This context-specific modulation of facial expression is thought to engage the amygdala, hippocampus, and orbitofrontal cortex; however, the underlying neural computations remain unknown. Here we use human intracranial electroencephalograms (EEGs) directly recorded from these regions and report bidirectional theta-gamma interactions within the amygdala-hippocampal network, facilitating contextual processing. Contextual information is subsequently represented in the orbitofrontal cortex, where a theta phase shift binds context and face associations within theta cycles, endowing faces with contextual meanings at behavioral timescales. Our results identify theta phase shifts as mediating associations between context and face processing, supporting flexible social behavior.

This paper presents a groove gap waveguide structure designed to serve as a feeding network for dual circularly polarized antenna arrays in the millimeter wave spectrum (28-32 GHz). The proposed structure comprises four groove gap waveguide elements arranged in a cross-shaped configuration. A turnstile integrated into the middle position of the structure divides the incoming RF signal into these four waveguide elements. Four matching posts are incorporated at the end of the various groove gap waveguide elements to route each corresponding RF signal to four WR-28 waveguide sections. These four sections form the output ports of the feeding network. The appropriate design of the pin distributions along the four groove gap elements allows the entire feeding network to achieve a specific phase shift between the output ports. As a proof of concept, the proposed feeding network is connected to a dual circularly polarized antenna array composed of four sub-arrays. Two of these sub-arrays emit right-handed circularly polarized waves, while the other two are designed to provide left-handed circularly polarized waves. A prototype of the feeding network demonstrates its ability to produce the needed circularly polarized radiation for a given distribution of the pins along the various groove gap elements. The results show that the feeding network can achieve an insertion loss as low as 0.55 dB with a good impedance matching across the entire operational bandwidth. In addition, when the fabricated feeding network is connected to the dual-circularly polarized antenna prototype, a maximum realized gain of 15.14 dBic is obtained.

DC distribution systems are drawing huge attention from researchers and industries because of their many advantages over AC systems. Due to its various benefits, including isolation and good fault current performance which is a big challenge for DC grids. the three-phase dual active bridge (DAB) converter is one of the most widely used converters for high power applications. However, the existing modulation techniques of the three-phase DAB have some drawbacks including high peak current, very low voltage ratio limitation as well as low output current. This paper proposes a new modified asymmetrical duty cycle control (MADCC) method to enable fault ride through operation of the three-phase DAB. By having three independent control parameters, the modulation strategy presented here efficiently controls the peak current and allows for high output current, all the while ensuring the converter switches operate with soft switching. Both simulation and experimental verification have been performed to test the proposed schemes. A comparison has been made between the performance of the proposed scheme and other existing control methods, and their key features are outlined and emphasized. During reference DC voltage tracking, low ripple voltage, small overshoot, and nearly no steady-state error was attained. Experimental and simulation results also confirmed the high DC current injection capability of the proposed technique during short circuit faults. This improvement in fault ride-through capability (FRT) enhances the performance of the three-phase DAB converter.

Phase change materials (PCMs) are substances that can change their phase at a specific range of temperatures. This is the case in the temperature range and in the event that there is a brief gap between the supply of a particular quantity of energy and the demand for that quantity, these materials come in quite helpful. As a result, heating, ventilation, and air conditioning (HVAC) for the military, as well as waste heat recovery and thermal management. The simulation result of this proposed method is developed using Matlab and Simulink, the user is classified using a fuzzy logic control which helps to improve the energy consumption patterns which are they exhibit. Using this proposed method, we can perform several modes of operations which are toogled between the control, which achieves more amount of greater flexibility, also at same time it helps to reduce the usage of number of switches which are placed between various OM's. This is demonstrated by the fact that the fuzzy logic control is used. Therefore, the developed control logic reveals a promising potential for boosting the energy efficiency. We achieve nearly 85% of accuracy as a result which are very higher than comparing with the several existing methods. [ABSTRACT FROM AUTHOR]

High-speed flow visualization is utilized to study the effect of bi-modal forcing on an axisymmetric impinging jet at Reynolds number, based on the jet exit velocity and diameter, of Re D = 4233 . The forcing involves excitation using two frequencies simultaneously: the fundamental and subharmonic frequencies of the initial instability of the jet shear layer. The focus of the study is on the effect of the intermodal phase ϕ while utilizing the same modal amplitude ratio and forcing level. The natural jet and the jet forced using pure harmonic forcing at the fundamental and the subharmonic frequency are also studied as benchmark cases for bi-modal forcing. Results show that all modes of forcing accelerate the development of the jet vortex structure by producing two vortex pairings ahead of the impingement plate. This double-paired structure is rarely seen in the natural jet and is promoted the most under pure subharmonic forcing and bi-modal forcing. The intermodal phase is found to have a strong effect with the double-paired structure exhibiting symmetry and high cycle-to-cycle repeatability at ϕ ≈ 150 ∘ - 165 ∘ , or significant asymmetry and disorganization at ϕ ≈ 90 ∘ - 105 ∘ . The main distinction between bi-modal forcing at ϕ ≈ 150 ∘ - 165 ∘ and pure subharmonic forcing is that the double-paired vortex structure is more persistent and has better repeatability in the former case. With subharmonic forcing alone, the vortex structure exhibits some random switching between the symmetric double-paired structure and the asymmetric structure. Overall, the promotion of double pairing leads to faster narrowing of the jet core and stronger vortex–wall interaction. [ABSTRACT FROM AUTHOR]

The z-scan is a straightforward method of determining the phase shift generated on a laser beam as it passes through a nonlinear medium. It specifies the sign and amplitude of the phase change, Δ Φ 0 which is proportional to the change in the index of refraction, Δ n . Furthermore, z-scan determines the change in transmission induced by nonlinear absorption, which is proportional to the change in the absorption coefficient. The phase shift increases as the sample thickness increases and all the phase shifts pass through the same points for all values of sample thicknesses. In the closed aperture nonlinear refraction, the signal measured would shows a peak and valley as the sample is moved and the location of peak and valley depends on the sign of the nonlinear phase shift, Δ Φ 0 . [ABSTRACT FROM AUTHOR]

A study is carried out of the radial (across the magnetic shells) structure of quasi-monochromatic high-m Alfvén oscillations observed by the RBSP-A satellite on October 23, 2012 at 22.00–22.30 UT. To determine the radial structure of these oscillations, the "phase portraits" method is used, based on the analysis of the phase shift between transverse components of the magnetic field of oscillations. It is shown that the observed oscillations can be explained by poloidal Alfvén waves generated on two resonance surfaces located on both sides of the local maximum in the radial distribution of the Alfvén speed. In the direction along the geomagnetic field lines, these waves are the fundamental harmonic of standing Alfvén waves. In the radial direction, they are waves running in opposite directions from two poloidal resonance surfaces towards two other (toroidal) resonance surfaces. The polarization of the waves between these resonance surfaces changes from poloidal to toroidal. [ABSTRACT FROM AUTHOR]

Background The unprecedented influence of human activities on natural ecosystems in the 21st century has resulted in increasingly frequent large-scale changes in ecological communities. This has heightened interest in understanding such changes and effective means to manage them. Accurate interpretation of state changes is challenging because of difficulties translating theory to empirical study, and most theory emphasizes systems near equilibrium, which may not be relevant in rapidly changing environments. Scope We review concepts of long-transient stages and phase shifts between stable community states, both smooth, continuous and discontinuous shifts, and the relationships among them. Three principal challenges emerge when applying these concepts. The first is how to interpret observed change in communities – distinguishing multiple stable states from long transients, or reversible shifts in the phase portrait of single attractor systems. The second is how to quantify the magnitudes of three sources of variability that cause switches between community states: (1) 'noise' in species' abundances, (2) 'wiggle' in system parameters and (3) trends in parameters that affect the topography of the basin of attraction. The third challenge is how variability of the system shapes evidence used to interpret community changes. We outline a novel approach using critical length scales to potentially address these challenges. These concepts are highlighted by a review of recent examples involving macroalgae as key players in marine benthic ecosystems. Conclusions Real-world examples show three or more stable configurations of ecological communities may exist for a given set of parameters, and transient stages may persist for long periods necessitating their respective consideration. The characteristic length scale (CLS) is a useful metric that uniquely identifies a community 'basin of attraction', enabling phase shifts to be distinguished from long transients. Variabilities of CLSs and time series data may likewise provide proactive management measures to mitigate phase shifts and loss of ecosystem services. Continued challenges remain in distinguishing continuous from discontinuous phase shifts because their respective dynamics lack unique signatures. [ABSTRACT FROM AUTHOR]

Copyright of Frontiers of Information Technology & Electronic Engineering is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The limit cycle oscillation (LCO) in the transonic buffet on the fixed supercritical airfoil OAT15A under Ma = 0.73, AoA = 3.5° and Re≈3×106, is successfully simulated by means of the Reynolds Stress Model. Further, the buffet lock-in phenomena under prescribed pitch conditions near the buffet onset are also studied by evaluating the modified energy exchange based on the pitching component of the moment coefficients as well as the normalized relative phase map between the pitching component of the moment coefficients and the airfoil’s angular velocity. The zero energy transfer branches in the modified energy map fail to indicate the lock-in boundaries, while the normalized phase map generally outlines the lock-in boundaries for small pitch amplitudes near the buffet onset, which suggests that the lock-in occurs where the moment is in phase with the angular velocity at small pitch amplitudes near the buffet onset. For pitch amplitudes larger than 0.4°, the lock-in onset deviates from the phase shift, possibly due to the fact the instantaneous angle of attack can be lower than the buffet onset where the buffet phenomena may vanish.