Asymmetric Dynamics Research Articles

Bubbles and crashes: A tale of quantiles

Periodically collapsing bubbles, if they exist, induce asymmetric dynamics in asset prices. In this article, I show that unit root quantile autoregressive models can approximate such dynamics by allowing the largest autoregressive root to take values below unity at low quantiles, which correspond to price crashes, and above unity at upper quantiles, that correspond to bubble expansions. On this basis, I employ two unit root tests based on quantile autoregressions to detect bubbles. Monte Carlo simulations suggest that the two tests have good size and power properties, and can outperform recursive least‐squares‐based tests. The merits of the two tests are further illustrated in three empirical applications that examine Bitcoin, US equity and US housing markets. In the empirical applications, special attention is given to the issue of controlling for economic fundamentals. The estimation results indicate the presence of asymmetric dynamics that closely match those of the simulated bubble processes.

Time-reversal symmetry breaking in the chemosensory array reveals a general mechanism for dissipation-enhanced cooperative sensing

The Escherichia coli chemoreceptors form an extensive array that achieves cooperative and adaptive sensing of extracellular signals. The receptors control the activity of histidine kinase CheA, which drives a nonequilibrium phosphorylation-dephosphorylation reaction cycle for response regulator CheY. Cooperativity and dissipation are both important aspects of chemotaxis signaling, yet their consequences have only been studied separately. Recent single-cell FRET measurements revealed that kinase activity of the array spontaneously switches between active and inactive states, with asymmetric switching times that signify time-reversal symmetry breaking in the underlying dynamics. Here, we present a nonequilibrium lattice model of the chemosensory array, which demonstrates that the observed asymmetric switching dynamics can only be explained by an interplay between the dissipative reactions within individual core units and the cooperative coupling between neighboring units. Microscopically, the switching time asymmetry originates from irreversible transition paths. The model shows that strong dissipation enables sensitive and rapid signaling response by relieving the speed-sensitivity trade-off, which can be tested by future single-cell experiments. Overall, our model provides a general framework for studying biological complexes composed of coupled subunits that are individually driven by dissipative cycles and the rich nonequilibrium physics within.

Triboelectric Programmed Droplet Manipulation for Plug‐and‐Play Assembly

AbstractProgrammed droplet transport which is typically directed by surface energy gradients or external fields, is crucial in domains ranging from chemical reaction modulation to self‐powered intelligent sensing. However, droplet motion control remains constrained by path reconfiguration, requirements on chemical surface modification, and platform complexity. Here, a more universal plug‐and‐play droplet manipulation paradigm based on liquid‐solid contact electrification and triboelectricwetting on common dielectric surfaces is reported. By regulating the electrical double layer via asymmetric ion dynamics, the triboelectric charge polarity of droplets can be adjusted, enabling in situ manipulation without path reconfiguration dictated by the conventional droplet motion output. Droplets achieved an ultrahigh velocity of 450 mm s−1 on general surfaces, significantly exceeding the speeds observed in droplets subjected to constant electrostatic fields with chemical modifications. This flexible and modular functionally decoupled manipulation strategy offers an environmentally friendly, cost‐effective, and versatile paradigm, facilitating applications in chemical analysis and smart sensing.

Finite Time Stability Analysis and Feedback Control for Takagi–Sugeno Fuzzy Time Delay Fractional-Order Systems

This study treats the problem of Finite Time Stability Analysis (FTSA) and Finite Time Feedback Control (FTFC), using a Linear Matrix Inequalities Approach (LMIA). It specifically focuses on Takagi–Sugeno fuzzy Time Delay Fractional-Order Systems (TDFOS) that include nonlinear perturbations and interval Time Varying Delays (ITVDs). We consider the case of the Caputo Tempered Fractional Derivative (CTFD), which generalizes the Caputo Fractional Derivative (CFD). Two main results are presented: a two-step procedure is provided, followed by a more relaxed single-step procedure. Two examples are presented to show the reduction in conservatism achieved by the proposed methods. The first is a numerical example, while the second involves the FTFC of an inverted pendulum, which exhibits both symmetrical dynamics for small angular displacements and asymmetrical dynamics for larger deviations.

Asymmetric Effects of Trade Openness, Financial Development, and Human Capital on Economic Growth in South Asia

ABSTRACT This study uses the nonlinear autoregressive distributed lag (NARDL) model to explore the relationship between trade openness and output growth in South Asia from 1980 to 2019. Findings reveal significant short- and long-term effects, with asymmetric dynamics. In linear ARDL models, Pakistan and India show strong positive correlations, while Bangladesh shows a negative one. Non-linear modeling reduces these effects, but Nepal still benefits. Sri Lanka’s linear model indicates a non-significant negative correlation, while the non-linear model reveals a positive relationship. These results highlight the complex dynamics between trade openness and economic growth in South Asia.

Enhancing underwater unmanned vehicle efficiency through asymmetric dynamics in manta-like swimming

This study explores the hydrodynamic performance of a National Advisory Committee for Aeronautics 0012 foil using computational fluid dynamics with the unsteady Reynolds-averaged Navier–Stokes (URANS) method and shear stress transport k-ω model to assess the impact of asymmetric motion parameters in manta-like swimming. The angles of attack during the mid-upstroke (αmu), mid-downstroke (αmd), and stroke duration (S) are varied to understand their effect. At low Strouhal numbers (StA = 0.2–0.35), a smaller αmd compensates for thrust loss at the start of the upstroke due to a greater αmu. At high Strouhal numbers (StA = 0.5), a greater αmd reduces negative thrust and compensates for the smaller thrust generated by a small αmu during the upstroke. Shorter stroke durations increase asymmetry, leading to more significant positive thrust peaks during the downstroke. If both the angle of attack and S are large, the slower downward speed extends negative thrust, reducing thrust peaks and lowering average thrust. A smaller stroke duration combined with a large angle of attack enhances efficiency due to a greater thrust-to-power ratio, highlighting the interplay between these parameters. A smaller S and greater αmd and StA maximize thrust and efficiency, suggesting aquatic organisms increase thrust while ensuring propulsion efficiency by using a large angle of attack and an asymmetric stroke duration. This study demonstrates how asymmetric parameters interact, providing insights into designing biomimetic underwater vehicles. The findings suggest that asymmetric dynamics enhance propulsion efficiency.

Dynamics of Stock Prices and Exchange Rate with Structural Breaks and Asymmetry: Evidence From Türkiye

This study investigates the impacts of the nominal exchange rate on Turkish stock prices using a structural break cointegration test with endogenously determined multiple structural breaks and an asymmetric cointegration test for the period of 2002-2021. The study differs from previous research on this relation in two respects. First, it takes into account structural breaks in relation to both regimes and trends (C/S/T). Second, it extends the asymmetric cointegration with multiple structural breaks. The findings of structural break cointegration capture the break dates in line with the Turkish economics dynamics and reveal the negative effects of the exchange rates on stocks, with their significance and magnitude differing in regimes. Similarly, NARDL results indicate that negative and positive exchange rate shocks exhibit asymmetric effects on stocks for both the whole period and regimes. The overall findings demonstrate that exchange rate variations have distinctive impacts on stock prices when considering structural break and asymmetrical dynamics. In this background, policymakers and foreign investors need to take into account these dynamics when dealing with Turkish financial markets.

Asymmetric and threshold price transmission dynamics in onion markets in India

Asymmetric and threshold price transmission dynamics in onion markets in India

Visions of Migration: News Images and the Production of Knowledge on the U.S. Southern Border

This monograph investigates the visual construction of migration on the U.S. southern border by the U.S. news industry. This study employs a quantitative ( N = 1,050) and qualitative ( N = 21) social semiotic analysis to illuminate the pervasive patterns of visual representation by three news agencies: The Associated Press, Getty Images, and Reuters. The analysis reveals levels of symbolic annihilation, social separation, and asymmetrical power dynamics that contribute to the symbolic othering of migrants. In-depth interviews with 21 photojournalists and field observation of an additional five photojournalists on the U.S.-Mexico border in Texas were conducted to analyze the factors that influence the production of images. Photojournalists are subject to myriad physical, social, and ideological influences from politicians, law enforcement, news organizations, non-governmental organizations, drug cartels, and border residents that constrain the depiction of migration. These complex conditions of production are marked by a scarcity of time, money, and autonomy that ultimately result in conventionalized imagery. The findings suggest that more comprehensive, nuanced, and humanizing accounts of migration can occur when external entities do not intercede in the interaction between photographers and migrants. Unconventional imagery, however, is no guarantee of empathetic reception from audiences who are steeped in hegemonic migration discourses produced by institutions that profoundly profit from a perpetual migration “crisis.”

Asymmetric Dynamics Drive Catalytic Activation of the Hsp90 Chaperone.

The Hsp90 chaperone is an ATPase enzyme composed of two copies of a three-domain subunit. Hsp90 stabilizes and activates a diverse array of regulatory proteins. Substrates are bound and released by the middle domain through a clamping cycle involving conformational transitions between a dynamic open state and a compact conformationally restricted closed state. Intriguingly, the overall ATPase activity of dimeric Hsp90 can be asymmetrically enhanced through a single subunit when Hsp90 is bound to a cochaperone or when Hsp90 is composed of one active and one catalytically defunct subunit as a heterodimer. To explore the mechanism of asymmetric Hsp90 activation, we designed a subunit bearing N-terminal ATPase mutations that demonstrate increased intra- and interdomain dynamics. Using intact Hsp90 and various N-terminal and middle domain constructs, we blended 19F NMR spectroscopy, molecular dynamics (MD) simulations, and ATPase assays to show that within the context of heterodimeric Hsp90, the conformationally dynamic subunit stimulates the ATPase activity of the normal subunit. The contrasting dynamic properties of the subunits within heterodimeric Hsp90 provide a mechanistic framework to understand the molecular basis for asymmetric Hsp90 activation and its importance for the biological function of Hsp90.

Migration Preferences Under Economic and Geopolitical Uncertainty: An Asymmetric Approach

Abstract This paper aims at assessing asymmetric dynamics among migration preferences and various security and economic factors, focusing on the movements from Syria to Turkey and then to the EU via the Greek sea borders (2010M1−2022M12). We perform an economic analysis by developing a utility model, according to which migration preferences depend on security and employment and empirically test asymmetric responses of migration to corresponding shocks. We contribute to the literature by finding that migration is downwards sticky. Despite that theories of international relations may not be monolithic, the magnitude of security impact on migration implies that the state remains the primary actor responsible for managing this phenomenon, which brings us closer to neo-realism theory of International Relations (IR). Our findings reveal the factors that lead to the downwards stickiness of migration thus contributing to a better understating of the incentives for migration and to the formulation of more efficient policies.

Exploring asymmetric dynamics of R&D spending and firm value nexus: Insights from panel autoregressive distributed lag analysis

Exploring asymmetric dynamics of R&D spending and firm value nexus: Insights from panel autoregressive distributed lag analysis

Short-time asymmetric droplet coalescence dynamics on a pre-wetted fiber

This study presents an unprecedented directional transport phenomenon during the coalescence of two droplets on a pre-wetted cylindrical fiber, where the larger droplet is pulled toward the smaller one. The magnitude of this effect often exceeds the gravitational pull, enabling coalescing droplets to climb up a vertical fiber. This occurs primarily because the viscous friction that the droplets experience is negatively correlated with the droplet size. We present a scaling relation and a mass-spring-damper model to explain the phenomenon, which shows good agreement with the experimental results. This research reveals an intriguing aspect of the coalescence dynamics of droplets on a pre-wetted fiber, offering a fresh perspective on the interfacial phenomena in droplet–fiber systems.

Asymmetric Tidal Dynamics in the Macro-tidal Hangzhou Bay, China

Asymmetric Tidal Dynamics in the Macro-tidal Hangzhou Bay, China

Investigating the asymmetric impact of artificial intelligence on renewable energy under climate policy uncertainty

The focus on sustainable development and the transition to renewable energy sources has intensified due to the risks associated with climate change. This study provides new insights into the impact of artificial intelligence (AI) and climate policy uncertainty (CPU) on the development of renewable energy (RE) in China. Utilizing a nonlinear autoregressive distributed lag (NARDL) framework, the asymmetric relationship between these variables from January 2013 to April 2023 is revealed. The empirical results indicate a significant positive asymmetric effect of AI on RE development, with downturns in AI having a more pronounced influence compared to upswings. Additionally, CPU has a positive effect on RE development, also exhibiting an asymmetric pattern where declines in CPU have a more substantial impact than upturns. These findings highlight the critical roles of AI and CPU in renewable energy development and add new dimensions to existing research. Policymakers should consider these asymmetric dynamics when formulating strategies to facilitate the energy transition through climate policymaking and the advancement of AI-driven technologies.

Study on the interior equilibrium point of a special class of 2 × 2 × 2 asymmetric evolutionary games.

Many behavioural interactions in real life involve three individuals. When each individual has two alternative strategies, they can be abstracted into mathematical models by means of asymmetric games. In this paper, we explore a special class of asymmetric games satisfying fixed conditions. Firstly, we analyse two solitary interior equilibrium points and provide the judgement condition for their instability based on the Jacobi matrix local stability analysis method. Secondly, we analyse the interior equilibrium points that are continuously distributed within a line and probe into their stability conditions based on generalized Hamiltonian systems theory. Under the circumstances, the stable interior equilibrium point is surrounded by closed orbits in phase space, which presents an observable stable state where two strategies coexist and fluctuate in each of the three game populations. This work enriches the study of asymmetric games' evolutionary dynamics.

Asymmetric spatial competition and dynamics in digitalization: Will public R&D support and marketization exacerbate spatial polarization?

This paper investigates the asymmetric spatial spillover effects of digital development across different types of cities. The results of the two-regime spatial Durbin models, using the panel data of 279 cities in China from 2011 to 2021, reveal the spatial polarization phenomenon in digitalization, where stronger cities such as smart cities, provincial capitals, and port cities become more dominant while weaker cities struggle to catch up. Increasing public R&D support leads to positive spatial spillover effects but exacerbates the spatial “Matthew effect” of digitalization. Additionally, marketization plays a moderating role by enhancing resource allocation efficiency and suppressing negative spatial spillover effects. Higher levels of marketization result in smaller digital gaps between cities. The findings provide valuable insights for decision-makers and stakeholders seeking to foster balanced and inclusive urban development in the digital age.

Predictive analysis of stochastic stock pattern utilizing fractional order dynamics and heteroscedastic with a radial neural network framework

Modelling of high-dimension chaotic, noisy, and non-stationary time series of complex fractal dynamics is a big challenge. In this research work, a novel approach of Leverage Convolution LC ARFIMA– GARCH model is presented for sequential learning of irregular, fractal dynamic patterns of stochastic time series dynamics. Different classical methods including the auto-regressive approach indecently are unable to capture fragile patterns and consequently convert some weak signals into random errors by creating white noise patterns. The Convolution Leverage provides an additional degree of freedom for critical noisy points and asymmetrical distribution dynamics to regulate the frequency of imbalance and skewed observation. The designed transformation in the ARFIMA model preserves the loss of information by shifting the skewed data distribution toward a normal pattern. The pattern of population parameters in the proposed leverage paradigm provides out of box approach to track and extract additional information on population variance patterns in the form of an additional degree of freedom to stabilize imbalance signals. The model can provide reliable performance for long-range dependence, particularly for mean reversion chaotic phase variation at critical non-differentiable points. The performance of the dynamic model is verified on chaotic real data of the Ireland Stock Market (ISEQ). The result statistics confirmed the optimized outcome with the addition of the GARCH heteroscedastic multimodal and radial basis neural network. The novel technique can help to address inherited challenges in the imbalance learning and extreme events of the time series modeling by monitoring the chaotic trajectory of fractal physical phenomena, particularly in, finance healthcare, climate, and intelligent sustainability.

Charge-symmetric and -asymmetric fragmentation dynamics of argon dimers in slow Ar8+–Ar2 collisions

We present an experimental study of multiple-electron capture-induced fragmentation dynamics of Ar2m+ (4 ≤m≤ 7) dimer ions in 4 keV/u Ar8+–Ar2 collisions. The fragment recoil ion pairs and the charge-changing projectiles are coincidentally measured using a double coincidence technique. The branching ratios between the different charge-sharing fragmentation channels show an inherent enhancement of the asymmetric channels. The kinetic energy release (KER) distributions for the associated electron capture process show a shift in the mean KER values toward the higher side with increasing capture stabilization. The interplay between the different projectile autoionization processes sheds light on the energy depositions to the system during collisions. The Coulomb potential energy curves give a physical insight into the role of the projectile final states in the dimer fragmentation dynamics. The dimer-axis orientation-dependent cross sections for the asymmetric fragmentation channels reveal a forward–backward asymmetry that arises from the geometry of the collision system. Our findings thus give insight into the impact parameter-controlled fragmentation dynamics of multiply charged Ar2m+ dimer ions in highly charged ion–dimer slow collisions.

Asymmetric fin shape changes swimming dynamics of ancient marine reptiles’ soft robophysical models

Animals have evolved highly effective locomotion capabilities in terrestrial, aerial, and aquatic environments. Over life’s history, mass extinctions have wiped out unique animal species with specialized adaptations, leaving paleontologists to reconstruct their locomotion through fossil analysis. Despite advancements, little is known about how extinct megafauna, such as the Ichthyosauria one of the most successful lineages of marine reptiles, utilized their varied morphologies for swimming. Traditional robotics struggle to mimic extinct locomotion effectively, but the emerging soft robotics field offers a promising alternative to overcome this challenge. This paper aims to bridge this gap by studying Mixosaurus locomotion with soft robotics, combining material modeling and biomechanics in physical experimental validation. Combining a soft body with soft pneumatic actuators, the soft robotic platform described in this study investigates the correlation between asymmetrical fins and buoyancy by recreating the pitch torque generated by extinct swimming animals. We performed a comparative analysis of thrust and torque generated by Carthorhyncus, Utatsusaurus, Mixosaurus, Guizhouichthyosaurus, and Ophthalmosaurus tail fins in a flow tank. Experimental results suggest that the pitch torque on the torso generated by hypocercal fin shapes such as found in model systems of Guizhouichthyosaurus, Mixosaurus and Utatsusaurus produce distinct ventral body pitch effects able to mitigate the animal’s non-neutral buoyancy. This body pitch control effect is particularly pronounced in Guizhouichthyosaurus, which results suggest would have been able to generate high ventral pitch torque on the torso to compensate for its positive buoyancy. By contrast, homocercal fin shapes may not have been conducive for such buoyancy compensation, leaving torso pitch control to pectoral fins, for example. Across the range of the actuation frequencies of the caudal fins tested, resulted in oscillatory modes arising, which in turn can affect the for-aft thrust generated.