# gst: stochastic adaptation, stochastic resonance.

<< Stochastic resonance is a phenomenon possessed by some nonlinear oscillators, in which a weak signal is boosted by noise. Both the monostable and bistable Duffing oscillators can exhibit this property. However, stochastic resonance has a strong frequency-dependence, as only a band of frequencies may be boosted by noise. >>️

<< Adaptive oscillators are a subset of nonlinear oscillators that can learn the features of an external force. (In this AA work), an adaptive state is added to a Duffing oscillator. This adaptive state enables the Duffing adaptive oscillator to outperform stochastic resonance over a wide range of frequencies by learning a resonance condition. >>️

Edmon Perkins. Comparison of stochastic adaptation and stochastic resonance. Phys. Rev. E 110, 064225. Dec 27, 2024.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.110.064225 

Also: fluctuations, noise, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, fluctuations, noise, transition, stochasticity, stochastic adaptation, stochastic resonance

# gst: nascent water waves induced by the impulsive motion of a solid wall; an unsteady hydraulic jump theory

Fig. 2: Representative cases of the different regimes of impulse waves observed: (a) dispersive wave; (b) solitary-like wave; (c) plunging breaking bore; (d) water jet 

AA << investigated the generation phase of laboratory-scale water waves induced by the impulsive motion of a rigid piston, whose maximum velocity U and total stroke L are independently varied, as well as the initial liquid depth h. By doing so, the influence of two dimensionless numbers is studied: the Froude number Frp (..), with g the gravitational acceleration, and the relative stroke Λp (..) of the piston. >>️

<< For large Froude numbers, an unsteady hydraulic jump theory is proposed, which accurately predicts the time evolution of the wave amplitude at the contact with the piston throughout the generation phase. At the end of the formation process, the dimensionless volume of the bump evolves linearly with Λp and the wave aspect ratio is found to be governed by the relative acceleration γ/g. As the piston begins its constant deceleration, the water bump evolves into a propagating wave and several regimes (such as dispersive, solitary-like and bore waves, as well as water jets) are then reported and mapped in a phase diagram in the (Frp, Λp) plane. While the transition from waves to water jets is observed if the typical acceleration of the piston is close enough to the gravitational acceleration g, the wave regimes are found to be mainly selected by the relative piston stroke Λp while the Froude number determines whether the generated wave breaks or not. >>️

️

Wladimir Sarlin, Zhaodong Niu, et al. Nascent water waves induced by the impulsive motion of a solid wall. arXiv: 2412.08216v1 [physics.flu-dyn]. Dec 11, 2024. 

https://arxiv.org/abs/2412.08216

Also: waves, soliton, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, waves, soliton

# gst: bent and reverse bent solitons; obliquely interacting solitary waves and wave wakes in free-surface flows.

This AA paper << investigates the weakly nonlinear isotropic bi-directional Benney-Luke (BL) equation, which is used to describe oceanic surface and internal waves in shallow water, with a particular focus on soliton dynamics. Using the Whitham modulation theory, (AA) derive the modulation equations associated with the BL equation that describe the evolution of soliton amplitude and slope. By analyzing rarefaction waves and shock waves within these modulation equations, (AA) derive the Riemann invariants and modified Rankine-Hugoniot conditions. These expressions help characterize the Mach expansion and Mach reflection phenomena of bent and reverse bent solitons. >>

<< Furthermore, as a far-field approximation for the forced BL equation - which models wave and flow interactions with local topography - the modulation equations yield a slowly varying similarity solution. This solution indicates that the precursor wavefronts created by topography moving at subcritical or critical speeds take the shape of a circular arc, in contrast to the parabolic wavefronts observed in the forced KP equation. >>

Lei Hu, Xudan Luo, Zhan Wang. Obliquely interacting solitary waves and wave wakes in free-surface flows. arXiv: 2412.05034v1 [nlin.PS]. Dec 6, 2024. 

https://arxiv.org/abs/2412.05034

Also: waves, soliton, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, waves, solitons

# gst: chimera states in a system of stationary and flying-through deterministic particles with an internal degree of freedom.

<< This work greatly extends (AA)  understanding of the dynamics of flying-through oscillators in media with nonlocal interaction. >>

<< Let’s describe the results obtained. First, it was shown that, depending on the number of potential wells, particles can be stationary, flying-through, or split into two subensembles of stationary and flying-through particles.  Secondly, it has been demonstrated that in the case of stationary arrangement of particles, the fully synchronous regime can become unstable due to the inhomogeneity of particle distribution between potential wells. In a partially synchronous cluster, phase incoherent elements can be located within the same potential well. Third, when stationary and flying-through elements coexist, chimera regimes are realized at each subensemble and further coexist with each other. This means that, despite the nonlocal nature of the interaction between elements of the medium, what is important for structure formation is a relatively stable mutual arrangement of particles relative to each other, which leads to a chimera state in each of the subensemble. >>️

Maxim I. Bolotov, Lev A. Smirnov, et al. Chimera states in a system of stationary and flying-through deterministic particles with an internal degree of freedom. arXiv: 2412.05044v1 [nlin.CD]. Dec 6, 2024.

https://arxiv.org/abs/2412.05044

Also: chimera, chaos, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, chimera, chaos

# gst: apropos of interweavings, linking dispersion and stirring in randomly braiding flows.

     Fig. 5 (a)

<< Many random flows, including 2D unsteady and stagnation-free 3D steady flows, exhibit non-trivial braiding of pathlines as they evolve in time or space. (AA) show that these random flows belong to a pathline braiding 'universality class' that quantitatively links dispersion and chaotic stirring, meaning that the Lyapunov exponent can be estimated from the purely advective transverse dispersivity. (AA) verify this quantitative link for both unsteady 2D and steady 3D random flows. This result uncovers a deep connection between transport and mixing over a broad class of random flows. >>️

Daniel R. Lester, Michael G. Trefry, Guy Metcalfe. Linking Dispersion and Stirring in Randomly Braiding Flows. arXiv: 2412.05407v1 [physics.flu-dyn]. Dec 6, 2024.

https://arxiv.org/abs/2412.05407

Also: random, chaos, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, random, random flows, randomly braiding flows, chaos

# life: apropos of impossible predictions, Lewis & Jackson (mjq) dipole, a bizarre form revisited

<< Qui un kernel di creativita' invece di autogenerarsi all'interno di un sistema cognitivo individuale emerge e si stabilizza grazie all' interazione cooperativa a lungo termine tra due personalita' ... >>

️

<< Qui si potrebbe introdurre un ulteriore elemento di impredicibilita'  (..) quasi una meccanica a metano protonato, per dire ... >>

️

2124 - attrattore cooperativo bipolare (nell'elastici spigoli). Notes. (quasi-stochastic poetry). Mar 05, 2007.

https://inkpi.blogspot.com/2007/03/2124-attrattore-cooperativo-bipolare.html   

Also: mjq, all the things you are (jazz night). 

https://youtu.be/6SLy0BhODLs?si=Pu43K2aYgBsbC3he

Also:  << Musk was indispensable to Trump’s campaign this year, endorsing the former president before pouring more than $100 million into the effort to elect him. Now he’s serving as one of Trump’s closest advisers, staying overnight at Mar-a-Lago and attending virtually every high-level meeting by his side. There are reports that he’s effectively living at the club. All of that was already inspiring headlines last month like, “Elon Musk may already be overstaying his welcome in Trump’s orbit.” >>

Eddie Scarry. Here’s How e Media Are Lying Right Now: Fake Trump-Musk. thefederalist.com. Dec 19, 2024.️

https://thefederalist.com/2024/12/19/heres-how-the-media-are-lying-right-now-fake-trump-musk-wedge-edition/

Also:  << In meno di tre giorni Elon Musk è riuscito a portare il governo degli Stati Uniti a un passo dalla chiusura e a interferire con le imminenti elezioni tedesche. Il tutto senza alzare gli occhi dal suo telefonino. È con un tweet sul social X ... >>️

Simona Siri. Il caso. lastampa.it  Dec 21, 2024.  https://www.lastampa.it/esteri/2024/12/21/news/elon_musk_germania_elezioni_ultradestra_afd-14899496/

Also: jazz, RAG-time, Mr. Donald, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, jazz, RAG-time, Mr. Donald, Mr. Elon

# gst: apropos of transitions, towards a theory for the formation of chimera patterns in complex networks

This AA work << formalizes a systematic method by evoking pattern formation theory to explain the emergence of chimera states in complex networks. >>

They << show that the randomness of network topology, as reflected in the localization of the graph Laplacian eigenvectors, determines the emergence of chimera patterns, underscoring the critical role of network structure. In particular, this approach explains how amplitude and phase chimeras arise separately and explores whether phase chimeras can be chaotic or not. (AA) findings suggest that chimeras result from the interplay between local and global dynamics at different time scales. >>

Malbor Asllani, Alex Arenas. Towards a Theory for the Formation of Chimera Patterns in Complex Networks. arXiv: 2412.05504v1 [nlin.AO]. Dec 7, 2024.

https://arxiv.org/abs/2412.05504

Also: chimera, network, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, chimera, network, transition

# life: They woke up in a body bag, by Van.

<< 'We woke up in a body bag': Van Jones makes stunning admission about why Trump steamrolled the establishment. >>️

Van Jones, << a former Obama adviser who had several weeks to get over his election-night despair, was particularly candid about how President-elect Donald Trump was able to electorally crush ... >>

️

<< After suggesting that the liberal political establishment is "all screwed up" and detached from the electorate and its wants and needs, Jones likened the media's predictions in the lead-up to the election to the ancient practice whereby a haruspex would read omens from animal entrails. >>️

<< 'We look like idiots.' >> Van Jones.

️

Joseph MacKinnon. 'We woke up in a body bag'. Blaze Media LLC. Dec 16, 2024. 

https://www.theblaze.com/news/we-woke-up-in-a-body-bag-van-jones-makes-stunning-admission-about-why-trump-steamrolled-the-establishment 

Chris Cillizza. Van Jones is the most honest man in politics. Dec 13, 2024. 

https://youtu.be/ZKd8ZM-TJU4

Also: Mr. Donald, RAG-time, dance, in https://www.inkgmr.net/kwrds.html 

Keywords: life, ethno, dance, Donald, POTUS, POTUSrace, RAG-time

# gst: vortex-pair dance and oscillation

       Fig. 4

This AA study << focuses on fundamental dynamics of vortex-pair fields, specifically known as vortex-pair beams (VPBs) in optics. VPBs have gained increasing attention due to their unique properties, including vortex attraction and repulsion. Here, (AA)  explore the dynamics of pure-phase VPBs (PPVPBs) and observe intriguing helical and intertwined behaviors of vortices, resembling a vortex-pair dance. >>

They << uncover the oscillation property of the intervortex distance for PPVPBs in free space. The observed dancing and oscillation phenomena are intricately tied to the initial intervortex distance and can be explained well in the hydrodynamic picture. Notably, the vortex dancing and oscillation alter the process of vortex-pair annihilation, extending the survival range for opposite vortices. >>

<< This discovery enhances our understanding of vortex interactions and sheds light on the intricate dynamics of both vortex-vortex and vortex-antivortex interactions. >>

Dadong Liu, Lai Chen, Li-Gang Wang. Observation of vortex-pair dance and oscillation. arXiv: 2412.06634v1 [physics.optics]. Dec 9, 2024.

https://arxiv.org/abs/2412.06634

Also: vortex, dance, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, vortex, dance 

# gst: self-organized chimera states in pulse-coupled oscillator systems.

<< Coupled oscillator systems can lead to states in which synchrony and chaos coexist. These states are called “chimera states.” >>

️

AA << study a variation of a pulse-coupled oscillator (PCO) model that has been shown to produce chimera states, demonstrate that it reproduces several of the expected chimera properties, like the formation of multiple heads and the ability to control the natural drift that Kuramoto's chimera states experience in a ring, and explain how chimera states emerge. >>️

<< Three notable aspects of chimeras in our PCO networks (with time-discrete coupling) are the absence of firing events from the tail (which still almost synchronize their phases), the reliable onset of the phenomenon from virtually any initial configuration, and the lack of a superimposed structure (e.g., artificially splitting the population into subgroups) and thus the self-organized nature of the phenomenon. >>️

Arke Vogell, Udo Schilcher, et al. Chimera states in pulse-coupled oscillator systems. Phys. Rev. E 110, 054214. Nov 26, 2024.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.110.054214 

Also: chimera, self-assembly, chaos, network,  in https://www.inkgmr.net/kwrds.html 

Keywords: gst, chimera, self-assembly, chaos, network 

# game: balance exploration and exploitation, making decisions cooperatively without sharing information.

<< Multiagent reinforcement learning (MARL) studies crucial principles that are applicable to a variety of fields, including wireless networking and autonomous driving. (AA) propose a photonic-based decision-making algorithm to address one of the most fundamental problems in MARL, called the competitive multiarmed bandit (CMAB) problem. >>

AA << demonstrate that chaotic oscillations and cluster synchronization of optically coupled lasers, along with (their) proposed decentralized coupling adjustment, efficiently balance exploration and exploitation while facilitating cooperative decision making without explicitly sharing information among agents. >>

AA << study demonstrates how decentralized reinforcement learning can be achieved by exploiting complex physical processes controlled by simple algorithms. >>

Shun Kotoku, Takatomo Mihana, et al. Decentralized multiagent reinforcement learning algorithm using a cluster-synchronized laser network. Phys. Rev. E 110, 064212. Dec 11, 2024.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.110.064212

Img: https://x.com/PhysRevE/status/1866889144657465632

Also: game, chaos, ai (artificial intell), in https://www.inkgmr.net/kwrds.html 

Keywords: game, cooperation, chaos, exploration, exploitation, ai, artificial intelligence, MARL, CMAB.

# gst: turbulence in viscous binary fluid mixtures induced by interfacial fluctuations.

AA << demonstrate the existence of interface-induced turbulence, an emergent nonequilibrium statistically steady state with spatiotemporal chaos, which is induced by interfacial fluctuations in low-Reynolds-number binary-fluid mixtures. >>️

<< Furthermore (they) demonstrate diffusive behavior at long times, a hallmark of strong mixing in turbulent flows. >>️

Nadia Bihari Padhan, Dario Vincenzi, Rahul Pandit. Interface-induced turbulence in viscous binary fluid mixtures. Phys. Rev. Fluids 9, L122401. Dec 3, 2024. 

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.9.L122401

Also: fluctuations, turbulence, transition,  in https://www.inkgmr.net/kwrds.html 

Keywords: gst, fluctuations, turbulence, transition 

# life: POTUS race, an extreme RAG-time revisited, they moved from Mr. Bernie to Mr. Donald.

<< In the final New York Times/Siena College national poll in late October, nearly two-thirds of voters said the government was “mostly working to benefit itself and the elites,” rather than “the people and the country.” Eighty-two percent of Trump voters said so, twice as many as Kamala Harris voters. >>

<< The idea resonated in particular with men and younger voters, the poll found — groups that Mr. Trump especially courted in this election and that Mr. Sanders did well with in his Democratic primary campaigns in 2016 and 2020. >>

Claire Cain Miller. How Some Voters Moved From Bernie Sanders to Donald Trump. Dec. 9, 2024. 

https://www.nytimes.com/2024/12/09/upshot/voters-trump-bernie-sanders.html

Also: RAG-time revisited. Notes (quasi-stochastic poetry). Feb 18, 2008. 

(RAG: Ralph, Al, George)

https://inkpi.blogspot.com/2008/02/2152-rag-time-revisited.html

Also: RAG-time, Mr. Donald, in https://www.inkgmr.net/kwrds.html 

Keywords: life, RAG-time, Mr. Donald, POTUS

# gst: apropos of puddles, how to design and stabilize a Leidenfrost puddle

<< Leidenfrost puddles exhibit erratic bubble bursts that release vapor trapped beneath the liquid, becoming amorphous and unstable. (AA) report a method to stabilize and design a Leidenfrost puddle. >>

<< When a thin hydrophilic layer with a suitable design is placed over the liquid, the puddle adopts the layer shape due to adhesive forces and becomes stable. (AA) show a variety of puddle designs with the required layer dimensions to avoid vapor accumulation, as well as wetting and buoyancy conditions. >>

<< With the layer, the puddle evaporation rate increases significantly and can be modified by varying the layer dimensions. Finally, an illustrative use of this method in a cooling process is presented. >>️

F. Pacheco-Vázquez, M. Aguilar-González, L. Victoria-García. Designing Leidenfrost Puddles. Phys. Rev. Lett. 133, 234001. Dec 4, 2024. 

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.133.234001 

Also: drop, bubble, instability, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, drops, bubbles, instability, transition

# gst: anomalous oscillation modes of (superfluid) pendant droplets; horizontal translation on a flat surface, bouncing off at the corner and vertical oscillations at the edge.

<< Droplets should exhibit various dynamical phenomena when adhered to a surface; not all of them are realized in classical fluids. Visualization of superfluid  4^He (helium-4) pendant droplets revealed that the droplets were horizontally translated on a flat surface, bouncing off at the corner, known as the Noether mode that reflects the translation symmetry. >>️

<< The droplets exhibited another mode in vertical oscillations with high amplitude that included oscillation of the droplet edge. The oscillation period remained constant even as the droplets grew, exhibiting an anomalously weak size dependence. The high mobility of the droplet edges owing to the superfluidity was a crucial factor for the appearance of these anomalous modes. >>️

Keita Onodera, Ryuma Nagatomo, et al. Anomalous Oscillation Modes of Superfluid Pendant Droplets. Phys. Rev. Lett. 133, 216001. Nov 19, 2024.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.133.216001

Also: drop, droplet, droploid, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, drop, droplet, droploid, transition

# gst: intermittency of bubble deformation in turbulence.

<< The deformation of finite-sized bubbles in intense turbulence exhibits complex geometries beyond simple spheroids as the bubbles exchange energy with the surrounding eddies across a wide range of scales. (AA)  study investigates deformation via the velocity of the most stretched tip of the deformed bubble in three dimensions, as the tip extension results from the compression of the rest of the interface by surrounding eddies. >>

<< The results show that the power spectrum based on the tip velocity exhibits a scaling akin to that of the Lagrangian statistics of fluid elements, but decays with a distinct timescale and magnitude modulated by the Weber number based on the bubble size. This indicates that the interfacial energy is primarily siphoned from eddies of similar sizes as the bubble. >>

<< Moreover, the tip velocity appears much more intermittent than the velocity increment, and its distribution near the extreme tails can be explained by the proposed model that accounts for the fact that small eddies with sufficient energy can contribute to extreme deformation. >>

<< These findings provide a framework for understanding the energy transfer between deformable objects and multiscale eddies in intense turbulence. >>

Xu Xu, Yinghe Qi, et al. Intermittency of Bubble Deformation in Turbulence. Phys. Rev. Lett. 133, 214001. Nov 19, 2024.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.133.214001

Also: bubble, turbulence, intermittency, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, bubble, turbulence, intermittency

# life: apropos of saliva healers, herd immunity revisited and now hypothetically approachable even within NIH

<< President-elect Donald Trump is tapping Dr. Jay Bhattacharya, a Stanford University health researcher, to be the next director of the National Institutes of Health (NIH). >>

️

<< Bhattacharya was one of three authors of the document (#1). The declaration called for speeding herd immunity by allowing people at low risk to get infected while protecting those most vulnerable, like the elderly. >>

Rob Stein. Trump turns to critic of COVID mandates to run NIH. npr.org. 

Nov 26, 2024. 

https://www.npr.org/sections/shots-health-news/2024/11/26/nx-s1-5195168/nih-bhattacharya-trump-election-2024

<< The most compassionate approach that balances the risks and benefits of reaching herd immunity, is to allow those who are at minimal risk of death to live their lives normally to build up immunity to the virus through natural infection, while better protecting those who are at highest risk. We call this Focused Protection. >>

️

(#1) - Martin Kulldorff, Sunetra Gupta, Jay Bhattacharya. Great Barrington Declaration. Oct 4, 2020. https://gbdeclaration.org/

FonT

From my point of view 'herd immunity'  can be engineered if and only if, even in the case of sars-covid-19 or flu, simultaneous protection is used with an effective, easy available, antiviral drug.

In this regard, a non-compassionate but logical easy approach could be the indirect inhalation of alcohol ~70% already at the first signs of rhinorrhea, as follows:

(-) start self-treatment (spray plus cotton mask):

Mar 20, 2020  https://flashontrack.blogspot.com/2020/03/life-funky-immediate-approach-of.html  

(-) outcomes

Jul 13, 2022  https://flashontrack.blogspot.com/2022/07/life-aproposito-di-1or2achoos-da-wuhan.html  

Oct 4, 2023 https://flashontrack.blogspot.com/2023/10/life-proposito-di-1or2achoos-da-wuhan.html  

Ultimately, here it could hypothesize a case of historic, singular checkmate of 'one against all'. Anzicheforse?

Also: drop, saliva, sars* covid* (aka 1or2achoos), virus, ethno, Mr. Donald, POTUS, tit-for-tat, game, in https://www.inkgmr.net/kwrds.html 

Keywords: life, drop, saliva, saliva healers, herd immunity, sars, mers, 2019ncov, sarscov2, covid19, coronavirus, 1or2achoos, virus, ethno, ethnomedicine, Donald, POTUS, tit-for-tat, game

PS: I couldn't say why, but in certain contexts, the incipit of an answer that the physicist Enrico Fermi https://it.m.wikipedia.org/wiki/Enrico_Fermi  gave to a journalist always comes back to my mind: 'the physics that is done in our laboratory ...' . 

An example of exceptional, clear, even poetic analysis and synthesis skills (in only 8 words).

# gst: apropos of diffusive anomalies, anomalous diffusion of active Brownian particles in responsive elastic gels.

Here, AA << examine via extensive computer simulations the dynamics of SPPs (self-propelled particles) in deformable gellike structures responsive to thermal fluctuations. (AA) treat tracer particles comparable to and larger than the mesh size of the gel. (They) observe distinct trapping events of active tracers at relatively short times, leading to subdiffusion; it is followed by an escape from meshwork-induced traps due to the flexibility of the network, resulting in superdiffusion. >>

AA << thus find crossovers between different transport regimes. (They) also find pronounced nonergodicity in the dynamics of SPPs and non-Gaussianity at intermediate times. The distributions of trapping times of the tracers escaping from “cages” in (..)  quasiperiodic gel often reveal the existence of two distinct timescales in the dynamics. At high activity of the tracers these timescales become comparable. >>

<< Furthermore, (AA) find that the mean waiting time exhibits a power-law dependence on the activity of SPPs (in terms of their Péclet number). (Their) results additionally showcase both exponential and nonexponential trapping events at high activities. Extensions of this setup are possible, with the factors such as anisotropy of the particles, different topologies of the gel network, and various interactions between the particles (also of a nonlocal nature) to be considered. >>

Koushik Goswami, Andrey G. Cherstvy, et al. Anomalous diffusion of active Brownian particles in responsive elastic gels: Nonergodicity, non-Gaussianity, and distributions of trapping times. Phys. Rev. E 110, 044609. Oct 29, 2024.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.110.044609

Also: particle, random, escape, network, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, particle, random, random walks, escape, network