# gst: self-organized target wave chimeras from asynchronous oscillators in reaction-diffusion media

<< An important development in nonlinear dynamics is the discovery of chimera states that represent the coexistence of synchronized and desynchronized activity in populations of identically coupled oscillators. >>

 Here, AA << unveil a novel chimera state called “self-organized target wave chimera” in reaction-diffusion media where synchronized target waves spontaneously emerge from a pacemaker composed of asynchronous oscillators. This regime contrasts with a widely accepted perspective that synchronized target waves can be generated only by the individuals, which comprise the pacemaker, behaving in a synchronized manner. >>

AA << characterize the features of self-organized target wave chimeras and present a phase diagram of existence of such a regime. >>

Bing-Wei Li, Jie Xiao, et al. Self-Organized Target Wave Chimeras in Reaction-Diffusion Media. Phys. Rev. Lett. 133, 207203. Nov 15, 2024. 

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.133.207203

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

Keywords: gst, chimera, self-assembly, waves, self-organized target wave chimera, asynchronous oscillators

# gst: singular bifurcations, an approach

<< Bifurcation analysis is traditionally based on the assumption of a regular perturbative expansion, close to the bifurcation point, in terms of a variable describing the passage of a system from one state to another. However, it is shown that a regular expansion is not the rule due to the existence of hidden singularities in many models, paving the way to a new paradigm in nonlinear science, that of singular bifurcations. The theory is first illustrated on an example borrowed from the field of active matter (phoretic microswimers), showing a singular bifurcation. >>

AA << then present a universal theory on how to handle and regularize these bifurcations, bringing to light a novel facet of nonlinear sciences that has long been overlooked. >>️

Alexander Farutin, Chaouqi Misbah. Singular bifurcations and regularization theory. Phys. Rev. E 109, 064218. Jun 27, 2024. 

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.109.064218

Alexander Farutin, Chaouqi Misbah. Singular Bifurcations : a Regularization Theory. arXiv: 2112.12094v2 [cond-mat.soft]. Jan 6, 2022. 

https://arxiv.org/abs/2112.12094 

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

Keywords: gst, transition, singularity, bifurcation

# gst: pulse-to-crack transition, unsteady slip pulses under spatially-varying prestress scenarios.

AA << study the effects of a spatially-varying prestress τb(x) on 2D slip pulses, initially generated under a uniform τb along a rate-and-state friction fault. (They) consider periodic and constant-gradient prestress τb(x) around the reference uniform τb. For a periodic τb(x), pulses either sustain and form quasi-limit cycles in the L−c plane or decay predominantly monotonically along the L(c) line, depending on the instability index of the initial pulse and the properties of the periodic τb(x).  >>️

<< For a constant-gradient τb(x), expanding/decaying pulses closely follow the L(c) line, with systematic shifts determined by the sign and magnitude of the gradient. (They) also find that a spatially-varying τb(x) can revert the expanding/decaying nature of the initial reference pulse.  >>

<< Finally, (AA) show that a constant-gradient τb(x), of sufficient magnitude and specific sign, can lead to the nucleation of a back-propagating rupture at the healing tail of the initial pulse, generating a bilateral crack-like rupture. This pulse-to-crack transition, along with the above-described effects, demonstrate that rich rupture dynamics merge from a simple, nonuniform prestress. >>️️

Anna Pomyalov, Eran Bouchbinder. Unsteady slip pulses under spatially-varying prestress. arXiv: 2407.21539v1 [cond-mat.mtrl-sci]. Jul 31, 2024.

https://arxiv.org/abs/2407.21539

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

Keywords: gst, transition, instability, crack 

# gst: apropos of transverse instabilities, from chimeras to extensive chaos

<< Populations of coupled oscillators can exhibit a wide range of complex dynamical behavior, from complete synchronization to chimera and chaotic states. We can thus expect complex dynamics to arise in networks of such populations. >>️

Here AA << analyze the dynamics of networks of populations of heterogeneous mean-field coupled Kuramoto-Sakaguchi oscillators, and show that the instability that leads to chimera states in a simple two-population model also leads to extensive chaos in large networks of coupled populations. >>️

Pol Floriach, Jordi Garcia-Ojalvo, Pau Clusella. From chimeras to extensive chaos in networks of heterogeneous Kuramoto oscillator populations. arXiv: 2407.20408v2 [nlin.CD]. Oct 11, 2024.

https://arxiv.org/abs/2407.20408

Also: chimera, instability, chaos, network, in 

https://www.inkgmr.net/kwrds.html 

Keywords: gst, chimera, instability, chaos, network

# gst: apropos of bubbles, the case of bubbles collapsing near a wall.

AA << study examines the pressure exerted by a cavitation bubble collapsing near a rigid wall. A laser-generated bubble in a water basin undergoes growth, collapse, second growth, and final collapse. Shock waves and liquid jets from non-spherical collapses are influenced by the stand-off ratio γ, defined as the bubble centroid distance from the wall divided by the bubble radius. (AA) detail shock mechanisms, such as tip or torus collapse, for various γ values. High-speed and Schlieren imaging visualize the microjet and shock waves. The microjet's evolution is tracked for large γ, while shock waves are captured in composite images showing multiple shock positions. Quantitative analyses of the microjet interface, shock wave velocities, and impact times are reported. Wall-mounted sensors and a needle hydrophone measure pressure and compare with high-speed observations to assess the dominant contributions to pressure changes with γ, revealing implications for cavitation erosion mechanisms. >>️

Roshan Kumar Subramanian, Zhidian Yang, et al. Bubble collapse near a wall. Part 1: An experimental study on the impact of shock waves and microjet on the wall pressure. arXiv: 2408.03479v2 [physics.flu-dyn]. Aug 8, 2024. 

https://arxiv.org/abs/2408.03479

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

Keywords: gst, bubble, bubble collapse 

# life: don't worry folks! Mr Donald will not run again in 2028. Anzicheforse?

<< In September, Donald Trump said he would run for president again in 2028 if he didn't win this week's general election. >>️

<< But on Tuesday, Donald Trump won the vote to become the 47th president of the United States. So, can he still run for office in 2028? >>️

<< And just a few months before that, at the NRA's annual meeting in May, Trump mentioned running for a third term. >>️

<< Here's what to know about term limits and if Trump can run for president a third time, now that he's won twice. >>

<< The 22nd Amendment to the Constitution ... >>️️

Lianna Norman, Joyce Orlando. Can Trump run for president again in 2028? Here’s what to know about term limits. USA TODAY NETWORK, Florida. Nov 7, 2024. 

https://eu.floridatoday.com/story/news/2024/11/07/trump-run-again-term-limits-22nd-amendment-constitution/76087581007/

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

Keywords: life, Donald, potus, potus race

# gst: phase transitions in anisotropic turbulence.

<<  

Turbulence is a widely observed state of fluid flows, characterized by complex, nonlinear interactions between motions across a broad spectrum of length and time scales. While turbulence is ubiquitous, from teacups to planetary atmospheres, oceans and stars, its manifestations can vary considerably between different physical systems. For instance, three-dimensional (3D) turbulent flows display a forward energy cascade from large to small scales, while in two-dimensional (2D) turbulence, energy cascades from small to large scales. In a given physical system, a transition between such disparate regimes of turbulence can occur when a control parameter reaches a critical value. The behavior of flows close to such transition points, which separate qualitatively distinct phases of turbulence, has been found to be unexpectedly rich. Here, (AA) survey recent findings on such transitions in highly anisotropic turbulent fluid flows, including turbulence in thin layers and under the influence of rapid rotation. (They) also review recent work on transitions induced by turbulent fluctuations, such as random reversals and transitions between large-scale vortices and jets, among others. The relevance of these results and their ramifications for future investigations are discussed.

>>️

Adrian van Kan. Phase Transitions in Anisotropic Turbulence. arXiv: 2408.02844v1 [physics.flu-dyn]. Aug 5, 2024. 

https://arxiv.org/abs/2408.02844

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

Keywords: gst, turbulence, vortex

# brain: mosaic evolution of a learning and memory circuit in Heliconiini butterflies.

<< A species of tropical butterfly with unusually expanded brain structures display a fascinating mosaic pattern of neural expansion linked to a cognitive innovation. >>

<< The study (..) investigates the neural foundations of behavioural innovation in Heliconius butterflies, the only genus known to feed on both nectar and pollen. As part of this behaviour, they demonstrate a remarkable ability to learn and remember spatial information about their food sources—skills previously connected to the expansion of a brain structure called the mushroom bodies, responsible for learning and memory. >>️

Butterfly brains reveal the tweaks required for cognitive innovation. University of Bristol. Oct 18, 2024. 

https://www.bristol.ac.uk/news/2024/october/butterfly-brains.html

Max S. Farnworth, Theodora Loupasaki, et al. Mosaic evolution of a learning and memory circuit in Heliconiini butterflies. Curr. Biol. doi: 10.1016/ j.cub.2024.09.069. Oct 18, 2024. 

https://www.cell.com/current-biology/fulltext/S0960-9822(24)01337-X

Also: brain, evolution, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, brain, evolution

# gst: taming uncertainty, a tutorial by NaN et Al.

<< All models are wrong, but some are useful. >>. George Box. ️

Nan Chen, Stephen Wiggins, Marios Andreou. Taming Uncertainty in a Complex World: The Rise of Uncertainty Quantification - A Tutorial for Beginners. arXiv: 2408.01823v1 [math.DS]. Aug 3, 2024. 

https://arxiv.org/abs/2408.01823

Also: NaN 'Not a Number'. In: Onda pneica. Apr 10, 2005 (quasi-stochastic poetry) https://inkpi.blogspot.com/2005/04/1694b-onda-pneica.html ;  nan(). In: Linux manual. https://www.man7.org/linux/man-pages/man3/nanf.3.html

Also: << Amico, qualunque  cosa suonerai . . . >>. Jelly Roll Morton. In: Soniche a ramulo. Jan 28, 2007 (quasi-stochastic poetry). https://inkpi.blogspot.com/2007/01/2113-soniche-ramulo.html  

Also: uncertainty, Mr. Jelly Roll Morton, jazz, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, uncertainty, Jelly Roll, jazz

# life: Potus race, Kamala knows her jazz

<< a video showing Harris emerging from a record store in Washington DC has recently gained massive traction on social media. The footage, taken in May 2023, shows her engaging with journalists while displaying and talking about the records she had purchased. This video clip was notably shared and reposted among the European jazz community – not people you’d necessarily think would be hugely interested in the musical tastes of US presidential candidates. >>

<< Harris’s purchases included three classic jazz albums by notable African American artists: Charles Mingus’s 1972 album Let My Children Hear Music, Roy Ayers’ 1976 Everybody Loves the Sunshine, and the 1959 collaboration of Ella Fitzgerald and Louis Armstrong on Porgy and Bess. >>️

<< Liking and knowing jazz, in some circles at least, suggests sophistication, intellectualism, and a leaning towards advocacy for cultural unity through diversity. The improvisational and creative elements found in jazz might also translate to a degree of flexibility in her politics. >>

<< The love of music is not necessarily an electoral strategy. But it would be interesting to find out which approach resonates most with voters ahead of the coming US election: scattergun and with no particular demographic focus, or targeted and consistent. >>

Haftor Medbøe, Jose Dias. US election 2024: Kamala Harris knows her jazz – why this could count with voters. theconversation.com. Aug 9, 2024.

https://theconversation.com/us-election-2024-kamala-harris-knows-her-jazz-why-this-could-count-with-voters-236344

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

Keywords: life, potus, potus race, jazz, RAG-time

# gst: apropos of noise-assisted phenomena, self-organized transport in noisy dynamic networks.

AA << present a numerical study of multicommodity transport in a noisy, nonlinear network. The nonlinearity determines the dynamics of the edge capacities, which can be amplified or suppressed depending on the local current flowing across an edge. (AA) consider network self-organization for three different nonlinear functions: For all three (They) identify parameter regimes where noise leads to self-organization into more robust topologies, that are not found by the sole noiseless dynamics. Moreover, the interplay between noise and specific functional behavior of the nonlinearity gives rise to different features, such as (i) continuous or discontinuous responses to the demand strength and (ii) either single or multistable solutions. (AA) study shows the crucial role of the activation function on noise-assisted phenomena. >>️

Frederic Folz, Kurt Mehlhorn, Giovanna Morigi. Self-organized transport in noisy dynamic networks. Phys. Rev. E 110, 044310. Oct 21, 2024. 

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.110.044310

Also: network, noise, behavior, self-assembly, instability, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, network, noise, behavior, self-assembly, stability 

# gst: monitoring of stable crack growth; crack tip behavior at the nanoscale (during ceramic fracture).

<< To understand fracture and make brittle materials more ductile, (AA) rely on modeling what happens at a crack tip. However, observing a crack tip in a brittle material is challenging: cracks propagate fast, and the events that (AA) are interested in observing occur at the nanoscale or below. Up to now, (They) were not able to observe what happens ahead of a moving crack tip. >>

<< In this work, (AA) show how by carefully performing fracture experiments inside a transmission electron microscope (They) can grow stable cracks while observing the nanoscale events happening at the crack tip. >>️

Oriol Gavalda-Diaz, Max Emmanuel, et al. Observing the crack tip behavior at the nanoscale during fracture of ceramics. PNAS. 121 (43) e2408292121. Oct 17, 2024.

https://www.pnas.org/doi/10.1073/pnas.2408292121 

Also: fracture, crack, behav in https://www.inkgmr.net/kwrds.html 

Keywords: gst, fracture, crack, behavior

# life: ghostly psyche revisited; ghosts, zombies, gris-gris, and so on ...

<< Most people imagine philosophers as rational thinkers who spend their time developing abstract logical theories and strongly reject superstitious beliefs. But several 20th-century philosophers actively investigated spooky topics such as clairvoyance, telepathy – even ghosts.

Many of these philosophers, including Henri Bergson and William James, were interested in what was called “psychical research”. This was the academic study of paranormal phenomena including telepathy, telekinesis and other-worldly spirits. These thinkers attended seances and were attempting to develop theories about ghosts, life after death and the powers exhibited by mediums in trances. >>

AA << recent archival research has been looking at how these topics shaped 20th-century philosophy. >>️

Matyas Moravec. Many important 20th-century philosophers investigated ghosts – here’s how they explained them. Oct 24, 2024. 

https://theconversation.com/many-important-20th-century-philosophers-investigated-ghosts-heres-how-they-explained-them-241635

Also: ethno, gris-gris, neuro, zombie, perception, psychedelic, delirium, in https://www.inkgmr.net/kwrds.html 

Keywords: ethno, gris-gris, neuro, zombie, perception, psychedelic, delirium 

FonT: even G.A. Romero's zombie filmography - which, as with other "spooky" themes, I have always marginalized - still seems relevant.

https://en.m.wikipedia.org/wiki/George_A._Romero

# game: Parrondo's paradox reveals counterintuitive wins in biology and decision making in society.

<< 

• Parrondo's paradox illustrates how combining two losing strategies can result in a winning outcome.

• Its applications extend across various disciplines, particularly in understanding ecosystems at different scales.

• The paradox is explored in multiple fields, highlighting adaptability as a key factor in evolutionary survival.

• Future directions are outlined, emphasizing the potential to enhance our understanding of the natural world and society.

 >>️

Tao Wen, Kang Hao Cheong. Parrondo's paradox reveals counterintuitive wins in biology and decision making in society. Physics of Life Reviews. 51, 33-59. Dec 19, 2024. 

https://www.sciencedirect.com/science/article/abs/pii/S1571064524000940 

Also: Parrondo, game, tit-for-tat, in https://www.inkgmr.net/kwrds.html 

Also: 'Parrondo paradox', in Pubmed  https://pubmed.ncbi.nlm.nih.gov/?term=parrondo+paradox&sort=date&size=50

Keywords: gst, Parrondo, game, tit-for-tat

FonT: as mentioned elsewhere in this blog, from my point of view, if well modulated, the two paired strategies "Stochastic Tit-For-Tat" and "Parrondo" are deadly, regardless of the aims of the objectives (cooperative purposes, parasitism, resurfacing of hypothetical clusters of failed entities, ... )

# life: landing on a swinging perch: peach-faced lovebirds (Agapornis roseicollis) prefer extremes.

<< Birds frequently must land safely and accurately on moving branches or power lines, and seemingly accomplish such maneuvers with acrobatic precision. To examine how birds target and land successfully on moving supports, (AA) investigated how peach-faced lovebirds (Agapornis roseicollis) approach and land on a swinging perch.  >>️

<< In support of (AA) hypothesis for stable landings, lovebirds timed their landings in a majority of trials (51.3%), when the perch was approaching either extreme of its motion with its velocity nearing zero (27.5% in the same direction as the bird’s approach – SDs, and 23.8% in the opposite direction to the bird’s approach – ODs). As a result, lovebirds exhibited a robust bimodal strategy for timing their landing to the phase of the swinging perch. Less commonly, lovebirds landed when the perch was moving at high velocity either toward the bird’s approach (12.3%) or in the same direction as the bird’s approach (11.5%); with the remainder (21.9%) of trials distributed over a broad range of swing phases. >>️

Partha S Bhagavatula, Andrew A. Biewener. Landing on a swinging perch: peach-faced lovebirds prefer extremes. biorxiv.org. Oct 8, 2024.

https://www.biorxiv.org/content/10.1101/2024.07.21.604435v2

Also: behav, birds, extreme, jazz, Mr. Jelly Roll Morton, in: https://www.inkgmr.net/kwrds.html 

Keywords: life, birds, extreme,  behavior, behaviour, jazz, Mr. Jelly Roll Morton

# life: fast-and-flexible decision-making with modulatory interactions

<< Multi-agent systems in biology, society, and engineering are capable of making decisions through the dynamic interaction of their elements. Nonlinearity of the interactions is key for the speed, robustness, and flexibility of multi-agent decision-making. >>

AA << introduce modulatory, that is, multiplicative, in contrast to additive, interactions in a nonlinear opinion dynamics model of fast-and-flexible decision-making. (..) Modulatory interactions introduce an extra source of nonlinearity that greatly enriches the model decision-making behavior in a mathematically tractable way. >>

AA << model provides new tools to understand the role of these interactions in networked decision-making and to engineer them in artificial systems. >>

Rodrigo Moreno-Morton, Anastasia Bizyaeva, et al. Fast-and-flexible decision-making with modulatory interactions. arXiv: 2410.00798v1 [math.DS]. Oct 1, 2024.

https://arxiv.org/abs/2410.00798

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

Keywords: life, decision-making, modulatory interactions, behavior, behaviour, network, ai, artificial intelligence

# game: aperiodic Parrondo (behavior based on the binary Fibonacci, Thue–Morse and Rudin–Shapiro sequences); persistence and heterogeneity effects.

AA << study the effectiveness of employing archetypal aperiodic sequencing -- namely Fibonacci, Thue-Morse, and Rudin-Saphiro -- on the Parrondian effect. From a capital gain perspective, (their) results show that these series do yield a Parrondo's Paradox with the Thue-Morse based strategy outperforming not only the other two aperiodic strategies but benchmark Parrondian games with random and periodical (AABBAABB…) switching as well. The least performing of the three aperiodic strategies is the Rudin-Shapiro. >>

AA << analyze the cross-correlation between the capital generated by the switching protocols and that of the isolated losing games. This analysis reveals that a pronounced anti-correlation (below -0.95) with both isolated games is typically required to achieve a robust manifestation of Parrondo's effect. >>

About << the influence of the sequencing on the capital using the lacunarity and persistence measures (AA) observe that the switching protocols tend to become less performing in terms of the capital as one increases the persistence and thus approaches the features of an isolated losing game. >>

Respect to << lacunarity, a property related to heterogeneity, (AA) notice that for small persistence the performance increases with the lacunarity with a maximum (..). In respect of this, (AA) work shows that  the optimisation of a switching protocol is strongly dependent on a fine tune between persistence and heterogeneity. >>

Marcelo A. Pires, Erveton P. Pinto, et al. Parrondo's effects with aperiodic protocols. arXiv: 2410.02987v1 [physics.soc-ph]. Oct 3, 2024.

https://arxiv.org/abs/2410.02987

Also: Parrondo, tit-for-tat, game, behav, network, in https://www.inkgmr.net/kwrds.html 

Keywords: Parrondo, tit-for-tat, game, behavior, behaviour, network

# game: apropos of Parrondo's paradox, winning with losses driven by reputation and reciprocity

AA << investigate two such social behaviors, reputation and reciprocity, and their role in explaining Darwin’s survival of the fittest, examining how these fundamental principles govern individual interactions and shape broader social dynamics. >>

<< Current theories hint at two main facets of social interaction, reputation and reciprocity, as potential drivers behind this cooperative evolution. Reputation revolves around building and sustaining trust, social worth, and overall community standing. Conversely, reciprocity governs the mutual exchange of actions or benefits, influencing our choices. >>

<< One intriguing concept explored in this domain is Parrondo’s paradox: combining or switching between two losing strategies might surprisingly achieve a winning outcome. The role of Parrondo’s paradox in complex systems has sparked key research into chaotic many-body, quantum, and algorithmic network applications, where combining elements yields opposing beneficial results. Similarly, social physicists aim to uncover hidden mechanisms that govern societal phenomena by integrating the paradox’s counterintuitive principles. >>️

<< The game-theoretic Parrondo’s paradox emerges through multiple iterations of these interactions (..) A naive observation might conclude that in either scheme the chance of individuals losing to the environment is higher than gaining from the environment. For the reputation scheme, one is rewarded with a singular capital from the environment but is punished with two. Similarly, the reciprocity scheme only allows for the redistribution of capital or loss of capital. In reality, diverse schemes can be adopted by different individuals. Thus, (AA) suggest two forms of switching: (1) stochastic switching, where the individual randomly selects one of two schemes to employ with equal probability, and (2) rule-based switching, where the individual only selects the reputation scheme if it passes the reputation threshold ρ; otherwise, it employs the reciprocity scheme. >>

AA << also performed simulations on other network topologies (..) Parrondo’s paradox is strongly observed in small-world networks, weakly in the Erdős-Rényi network, and absent in scale-free networks. >>

To conclude, some of these observations << underscore the profound capability of rule-based switching mechanisms inherent in Parrondo’s paradox to emulate and forecast key aspects of real-world social phenomena. Such insights are invaluable for developing sophisticated models and strategies in various fields, ranging from social sciences to policy making, where accurate predictions of social behavior and dynamics are crucial. >>

Joel Weijia Lai, Kang Hao Cheong. Winning with Losses: The Surprising Success of Negative Strategies in Social Interaction Behavior. Phys. Rev. Lett. 133, 167401. Oct 16, 2024. 

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.133.167401

Also: Parrondo, tit-for-tat, game, behav, network, in https://www.inkgmr.net/kwrds.html 

Keywords: Parrondo, tit-for-tat, game, behavior, behaviour, network

# gst: underdamped and overdamped scenarios of a one-dimensional inertial run-and-tumble particle

AA << study the nonequilibrium stationary state of a one-dimensional inertial run-and-tumble particle  trapped in a harmonic potential. (AA) find that the presence of inertia leads to two distinct dynamical scenarios, namely, overdamped and underdamped, characterized by the relative strength of the viscous and the trap timescales. >>

️

<< in the underdamped regime, both the position and velocity undergo transitions from a novel multipeaked structure in the strongly active limit to a single-peaked Gaussian-like distribution in the passive limit. On the other hand, in the overdamped scenario, the position distribution shows a transition from a U shape to a dome shape, as activity is decreased. Interestingly, the velocity distribution in the overdamped scenario shows two transitions—from a single-peaked shape with an algebraic divergence at the origin in the strongly active regime to a double-peaked one in the moderately active regime to a dome-shaped one in the passive regime. >>️

Debraj Dutta, Anupam Kundu, et al. Harmonically trapped inertial run-and-tumble particle in one dimension. Phys. Rev. E 110, 044107. Oct 4, 2024. 

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.110.044107

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

Keywords: gst, particle, transition 

# gst: isles of regularity (depending on the initial setup) in a sea of chaos amid the gravitational three-body problem.

AA << study probes the presence of regular (i.e. non-chaotic) trajectories within the 3BP (three-body problem) and assesses their impact on statistical escape theories. >>

AA << analysis reveals that regular trajectories occupy a significant fraction of the phase space, ranging from 28% to 84% depending on the initial setup, and their outcomes defy the predictions of statistical escape theories. The coexistence of regular and chaotic regions at all scales is characterized by a multi-fractal behaviour. >>

Alessandro Alberto Trani, Nathan W.C. Leigh, et al. Isles of regularity in a sea of chaos amid the gravitational three-body problem. A&A, 689, A24, Jun 25, 2024.

https://www.aanda.org/articles/aa/full_html/2024/09/aa49862-24/aa49862-24.html

"Islands" of Regularity Discovered in the Famously Chaotic Three-Body Problem. University of Copenhagen. Oct 11, 2024.

https://science.ku.dk/english/press/news/2024/islands-of-regularity-discovered-in-the-famously-chaotic-three-body-problem/

Also: three balls, escape, chaos, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, three balls, escape, chaos, transition 

# life: Future You

<< AI simulation gives people a glimpse of their potential future self. By enabling users to chat with an older version of themselves, Future You is aimed at reducing anxiety and guiding young people to make better choices. >>️

<< Have you ever wanted to travel through time to see what your future self might be like? Now, thanks to the power of generative AI, you can. >>️

Adam Zewe. AI simulation gives people a glimpse of their potential future self. MIT News. Oct 1, 2024.

https://news.mit.edu/2024/ai-simulation-gives-people-glimpse-potential-future-self-1001 

Pat Pataranutaporn, Kavin Winson, et al. Future You: A Conversation with an AI-Generated Future Self Reduces Anxiety, Negative Emotions, and Increases Future Self-Continuity. arXiv: 2405.12514v4 [cs.HC]. Oct 1, 2024. 

https://arxiv.org/abs/2405.12514

Try Future You  https://futureyou.media.mit.edu/

Also: ai (artificial intell), are you ready for all this?  in https://www.inkgmr.net/kwrds.html 

Keywords: life, ai, artificial intelligence, are you ready for all this

# gst: apropos of fluctuations, an unconventional approach to (fuzzy) morphogenesis

AA << propose an unconventional mechanism where stochastic fluctuations drive the emergence of morphological patterns. >>️

In this approach << the inherent fluctuations determine the nature of the dynamics and are not incidental noise in the background of the otherwise deterministic dynamics. Instead, they play an important role as a driving force that defines the attributes of the pattern formation dynamics and the nature of the transition itself.  >>️

Oded Agam and Erez Braun. Fluctuation-driven morphological patterning: An unconventional approach to morphogenesis. Phys. Rev. Research 6, 043027. Oct 10, 2024.

https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.6.043027

Also: disorder & fluctuations, self-assembly, metamorphosis, transition, noise, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, disorder, fluctuations,  self-assembly, metamorphosis, transition, noise

# gst: pensive billiards

AA << define a new class of plane billiards - the `pensive billiard' - in which the billiard ball travels along the boundary for some distance depending on the incidence angle before reflecting, while preserving the billiard rule of equality of the angles of incidence and reflection. This generalizes so called `puck billiards' (..), as well as a `vortex billiard', i.e. the motion of a point vortex dipole in 2D hydrodynamics on domains with boundary. (AA) prove the variational origin and invariance of a symplectic structure for pensive billiards, as well as study their properties including conditions for a twist map, the existence of periodic orbits, etc. (AA) also demonstrate the appearance of both the golden and silver ratios in the corresponding hydrodynamical vortex setting. Finally, (AA) introduce and describe basic properties of pensive outer billiards. >>

Theodore D. Drivas, Daniil Glukhovskiy, Boris Khesin. Pensive billiards, point vortices, and pucks. arXiv: 2408.03279v1 [math.DS]. Aug 6, 2024.

https://arxiv.org/abs/2408.03279

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

FonT: 'pensive billiard' evokes images in me that could inspire a series of quasi-stochastic short poems ( https://inkpi.blogspot.com ), but (for now) I will abstain.

Keywords: gst, billiards, pensive billiard, puck billiard, vortex billiard

# evol: flip of the script when an entity invert code sequences

<< Jekyll and Hyde flip of the script when bacteria invert gene sequences. If a cell can diversify its own genome, this can be advantageous in the face of changing environmental conditions. Bacteria have been found that can alter encoded proteins by using the trick of sequence inversion inside genes. >>️

Chia-Chi Chang, Robert R. Jenq. Jekyll and Hyde flip of the script when bacteria invert gene sequences. Nature 634, 42-43. Sep 25, 2024. 

https://www.nature.com/articles/d41586-024-02807-6

Chia-Chi Chang, Robert R. Jenq. Bacteria invert gene sequences to flip the script. Nature. Vol 634. Oct 3, 2024 (pdf)  https://media.nature.com/original/magazine-assets/d41586-024-02807-6/d41586-024-02807-6.pdf

Chanin RB, West PT, et al. Intragenic DNA inversions expand bacterial coding capacity. Nature. 2024 Oct; 634 (8032): 234-242. doi: 10.1038/s41586-024-07970-4. Sep 25, 2024. 

https://pubmed.ncbi.nlm.nih.gov/39322669/

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

Also: 

DNA https://flashontrack.blogspot.com/search?q=dna 

RNA https://flashontrack.blogspot.com/search?q=rna 

CODES https://flashontrack.blogspot.com/search?q=codes

Also (quasi-stochastic poetry): 

DNA  https://inkpi.blogspot.com/search?q=dna 

RNA https://inkpi.blogspot.com/search?q=rna 

CODICE https://inkpi.blogspot.com/search?q=codice

Keywords: evolution, codes, DNA, RNA

# gst: apropos of breaking mechanisms, crack of a floating particle raft caused by waves.

<< When particles of a few tens of microns are spread on the surface of water, they aggregate under the action of capillary forces and form a thin floating membrane, a particle raft. >>

<< For a sufficiently strong wave amplitude, the raft breaks up progressively by developing cracks and producing fragments whose sizes decrease on a timescale long compared to the period of the wave. (AA)  characterize the breaking mechanisms.  >>️️

<< The visual appearance of the fragments distributed in size and surrounded by open water bears a notable resemblance to the floes produced by the fracturing of sea ice by waves in the polar oceans. Fragmentation concepts and morphological tools built for sea ice floes can be applied to (AA) macroscopic analog, on which the entire dynamic evolution is accessible. However, the mechanics of the two systems differ, as (AA) particle raft breaks due to the viscous stresses, whereas the sea ice fractures due to its bending by the waves. >>️

Louis Saddier, Ambre Palotai, et al. Breaking of a floating particle raft by water waves. Phys. Rev. Fluids 9, 094302. Sep 27, 2024.

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.9.094302 

Also: 'crack', 'particle', in  https://www.inkgmr.net/kwrds.html 

Also: 'break' in  https://flashontrack.blogspot.com/search?q=break

Also: 'raft' in  https://flashontrack.blogspot.com/search?q=raft

Also: 'zattera' (quasi-stochastic poetry) in  https://inkpi.blogspot.com/search?q=zattera  'randa' (quasi-stochastic poetry) in https://inkpi.blogspot.com/search?q=randa

Keywords: gst, crack, break, particle, raft, particle raft

# gst: apropos of inertial particles, they dispersion in turbulent canopy flows with buoyant and nonbuoyant plumes.

<< In an idealized “wind-driven” model system, (AA) consider the impact of plume buoyancy, plume momentum, and canopy turbulence on the downstream transport of particles in the wake of a canopy, and in particular the mean and standard deviation of the distribution of landing sites. >>

<< In a first set of experiments, particles were released with a fixed starting elevation above the plumes' upper boundaries, such that the particles were not lofted by the plume. In these cases, observations suggest that plumes have a role in extending particles' streamwise transport by delaying their downward transport. The plumes also have a strong role in increasing absolute dispersion of the particles, although less so when dispersion is normalized by distance traveled. While canopy turbulence alone significantly increases particle dispersion, in the presence of the plume its impact is more limited. Canopy turbulence was also found to cause shorter mean landing positions. >>

<< In a second set of experiments, particles were released at the plume source/outlet such that their initial vertical momentum was provided by the plume's momentum and buoyancy. In these cases, the impact of canopy turbulence on particle transport is observed more distinctly. The canopy coherent structures introduce a mechanical instability to the plume, which manifests as vertical oscillatory motions that lead to variability in the particles' initial conditions and, therefore, trajectories. This leads to particles settling at both shorter and longer downstream distances. >>

Hayoon Chung, Laura K. C. Sunberg, et al. Dispersion of inertial particles in turbulent canopy flows with buoyant and nonbuoyant plumes. Phys. Rev. Fluids 9, 093801. Sept 25, 2024.

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.9.093801  

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

Keywords: gst, particle, turbulence

# brain: time delay in 'reservoir brain' as a reservoir network, a hypothesis

<< Both the predictive power and the memory storage capability of an artificial neural network called a reservoir computer increase when time delays are added into how the network processes signals, according to a new model. >>️

<< They also suggest that incorporating time delays could offer advantages to living neural networks (such as those found in human and animal brains). Such a finding would be tantalizing, as time delays are known to decrease performance in living systems. For example, for a baseball player facing an oncoming ball, a longer time delay between perception and action (which is learned from experience) will decrease the likelihood they hit a home run. Are there instead cases in which time delays increase an organism’s ability to perform some task? Has evolution shaped our brains, which could perhaps be thought of as a collection of reservoir computers, so that the time delay between one neuron sending a signal and a second receiving it is exactly the right length for understanding the visual and audio that constantly impinge upon our eyes and ears? Does adding time delays impact the number of neurons the brain needs to operate correctly? Further work is needed to answer these questions, but such work could lead to a new understanding of how biological organism’s function.  >>️

Sarah Marzen. Time Delays Improve Performance of Certain Neural Networks. Physics 17, 111. July 22, 2024. 

https://physics.aps.org/articles/v17/111 

Also: pause, silence, jazz, network, brain, ai (artificial intell), in https://www.inkgmr.net/kwrds.html 

Keywords: gst, brain, network, neural network, reservoir network, reservoir computer, time delay, ai, artificial intelligence

# gst: extreme events in two-coupled chaotic oscillators.

This AA study << focuses on the emergence of extreme events in a system of diffusively and bidirectionally two coupled Rössler oscillators and unraveling the mechanism behind the genesis of extreme events. (AA) find the appearance of extreme events in three different observables: average velocity, synchronization error, and one transverse directional variable to the synchronization manifold. >>

<< The emergence of extreme events in average velocity variables happens due to the occasional in-phase synchronization. The on-off intermittency plays for the crucial role in the genesis of extreme events in the synchronization error dynamics and in the transverse directional variable to the synchronization manifold. The bubble transition of the chaotic attractor due to the on-off intermittency is illustrated for the transverse directional variable. >>

S. Sudharsan, Tapas Kumar Pal, et al. Extreme events in two-coupled chaotic oscillators. arXiv: 2409.15855v1 [nlin.CD]. Sep 24, 2024. 

https://arxiv.org/abs/2409.15855

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

Keywords: gst, transition, bubble transition, extreme events

# gst: dynamics of pulsating spheres orbiting black holes.

AA << study the chaotic dynamics of spinless extended bodies in a wide class of spherically symmetric spacetimes, which encompasses black-hole scenarios in many modified theories of gravity. (They) show that a spherically symmetric pulsating ball may have chaotic motion in this class of spacetimes. >>

AA << use Melnikov's method to show the presence of homoclinic intersections, which imply chaotic behavior, as a consequence of (their)  assumption that the test body has an oscillating radius. >>

Fernanda de F. Rodrigues, Ricardo A. Mosna, Ronaldo S. S. Vieira. Chaotic dynamics of pulsating spheres orbiting black holes. arXiv: 2409.14667v1 [gr-qc]. Sep 23, 2024.

https://arxiv.org/abs/2409.14667

Also: black hole, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, black hole, homoclinic orbit, chaos, transition

# gst: complexity of a flat-foldings random origami

AA << give the result of approximate enumeration of the total number of flat-foldings of single-vertex origami diagram with random width of angles gathering around the central vertex, and obtain its size dependence for an asymptotic prediction towards the limit of infinite size. >>️

<< In addition, an outlook with respect to the chained determination of local stacking orders of facets caused by the constraint that prohibits the penetration of them is also provided from the viewpoint of organizing the terms included in the physical model. A method to efficiently solve the problem of the determination or enumeration of flat-foldings is discussed based on the above perspectives. >>️

Chihiro Nakajima. An Efficient Enumeration of Flat-Foldings : Study on Random Single Vertex Origami. arXiv: 2409.03240v1 [cond-mat.stat-mech]. Sep 5, 2024.

https://arxiv.org/abs/2409.03240

Also: origami, kirigami, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, origami, kirigami 

# life: anyone could now run small AIs privately on their laptops

<< Artificial-intelligence models are typically used online, but a host of openly available tools is changing that. Here’s how to get started with local AIs. >>️

Matthew Hutson. Forget ChatGPT: why researchers now run small AIs on their laptops. Nature 633, 728-729 (2024). Sep 16, 2024. Correction: Sep 24,  2024. 

https://www.nature.com/articles/d41586-024-02998-y

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

Keywords: gst, ai, artificial intelligence, life, Donald

FonT: In a completely bizarre hypothesis, with the right personal AI consultant, even a medieval history professor could be absolutely operational in other fields, for example in the agri-food sector (here we underline: absolutely).

In case of serious mistakes, the AI ​​entity can be held entirely responsible, or it can be blamed on an unfortunate malfunction due to hacking, anzicheforse. 

Also: << Asked if Strohschneider (Peter Strohschneider) wrote the report himself, the spokesperson said he “was able to propose language” for it and that a “limited number of staff” helped Strohschneider write it. >> Balazs Ujvari. 

Eddy Wax. Von der Leyen budgeted €149K to pay medieval history professor for farming report. Politico.eu. Sep 26, 2024 4:20 am CET. 

https://www.politico.eu/article/ursula-von-der-leyen-farming-agriculture-italy/

# gst: apropos of intermittent switchings, presence of chaotic saddles in fluid turbulence.

<< Intermittent switchings between weakly chaotic (laminar) and strongly chaotic (bursty) states are often observed in systems with high-dimensional chaotic attractors, such as fluid turbulence. They differ from the intermittency of a low-dimensional system accompanied by the stability change of a fixed point or a periodic orbit in that the intermittency of a high-dimensional system tends to appear in a wide range of parameters. >>️

Here AA << demonstrate the presence of chaotic saddles underlying intermittency in fluid turbulence and phase synchronization. Furthermore, (they) confirm that chaotic saddles persist for a wide range of parameters. Also, a kind of phase synchronization turns out to occur in the turbulent model. >>️

Hibiki Kato, Miki U Kobayashi, et al. A laminar chaotic saddle within a turbulent attractor. arXiv: 2409.08870v1 [nlin.CD]. Sep 13, 2024. 

https://arxiv.org/abs/2409.08870

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

Keywords: gst, transition, turbulence, intermittency, chaos

# gst: simultaneous presence of attraction and repulsion in quantum self-sustained oscillators

AA << study the emergent dynamics of quantum self-sustained oscillators induced by the simultaneous presence of attraction and repulsion in the coupling path. >>

They << discover an interesting symmetry-breaking transition from quantum limit cycle oscillation to a quantum inhomogeneous steady state. This transition is contrary to the previously known symmetry-breaking transition from a quantum homogeneous state to an inhomogeneous steady state. >>

<< Remarkably, (they) find the generation of entanglement associated with the symmetry-breaking transition that has no analog in the classical domain. >>

Bulti Paul, Biswabibek Bandyopadhyay, Tanmoy Banerjee. Attractive-repulsive interaction in coupled quantum oscillators. Phys. Rev. E 110, 034210. Sept 19, 2024. 

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.110.034210

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

Keywords: gst, transition, symmetry-breaking transition, noise, attractive-repulsive interaction, coupled qu-oscillator

# gst: a body of revolution with a cat’s toy mechanism.

AA << introduce a class of examples which provide an affine generalization of the nonholonomic problem of a convex body rolling without slipping on the plane. >>

️

They << prove that (this system can be) integrable if the generalized momentum M is vertical (i.e. parallel to γ) and exhibit numerical evidence that it is chaotic otherwise. >>️

M. Costa Villegas, L.C. García-Naranjo. Affine generalizations of the nonholonomic problem of a convex body rolling without slipping on the plane. arXiv: 2409.08072v1 [math-ph]. Sep 12, 2024. 

https://arxiv.org/abs/2409.08072

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

Keywords: gst, transition, chaos

# gst: vortex structures under dimples and scars in turbulent free-surface flows

<< Turbulence beneath a free surface leaves characteristic long-lived signatures on the surface, such as upwelling 'boils', near-circular 'dimples' and elongated 'scars', easily identifiable by eye, e.g., in riverine flows. >>️

AA << explore the connection between these surface signatures and the underlying vortical structures. We investigate dimples, known to be imprints of surface-attached vortices, and scars, which have yet to be extensively studied, by analysing the conditional probabilities that a point beneath a signature is within a vortex core as well as the inclination angles of sub-signature vorticity. >>️

<< The analysis shows that the likelihood of vortex presence beneath a dimple decreases from the surface down through the viscous and blockage layers in a near-Gaussian manner, influenced by the dimple's size and the bulk turbulence. When expressed as a function of depth over the Taylor microscale λT, this probability is independent of Reynolds and Weber number. >>️

<< Conversely, the probability of finding a vortex beneath a scar increases sharply from the surface to a peak at the edge of the viscous layer, at a depth of approximately λT/4. Distributions of vortical orientation also show a clear pattern: a strong preference for vertical alignment below dimples and an equally strong preference for horizontal alignment below scars. >>️

AA << findings suggest that scars can be defined as imprints of horizontal vortices approximately a quarter of the Taylor microscale beneath the surface, analogous to how dimples can be defined as imprints of surface-attached vertical vortex tubes. >>

Jørgen R. Aarnes, Omer Babiker, et al. Vortex structures under dimples and scars in turbulent free-surface flows. arXiv: 2409.05409v1 [physics.flu-dyn]. 

9 Sep 2024.

https://arxiv.org/abs/2409.05409

Also: vortex, turbulence, waves, bubble, drop, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, vortex, turbulence, waves, bubble, drop, transition

# gst: overlapping substitutions and tilings.

AA << generalize the notion of (geometric) substitution rule to obtain overlapping substitutions. For such a substitution, the substitution matrix may have non-integer entries. (They) also show that the expansion constant is an algebraic integer under mild conditions. In general, overlapping substitutions may yield a patch with contradictory overlaps of tiles, even if it is locally consistent. >>

AA << give a sufficient condition for an overlapping substitution to be consistent, that is, no such contradiction will emerge. (They) also give many one-dimensional examples of overlapping substitution. (AA) finish by mentioning a construction of overlapping substitutions from Delone multi-sets with inflation symmetry. >>️

Shigeki Akiyama, Yasushi Nagai, Shu-Qin Zhang. Overlapping substitutions and tilings. arXiv: 2407.18666v2 [math.CO]. Aug 30, 2024. 

https://arxiv.org/abs/2407.18666

Also

keyword 'tile', in FonT

https://flashontrack.blogspot.com/search?q=tile 

keyword 'overlap', 'overlapping', in FonT

https://flashontrack.blogspot.com/search?q=overlap 

https://flashontrack.blogspot.com/search?q=overlapping

Keywords: gst, tiles, overlap, overlapping

# gst: critical crack length during fracture.

AA << established an inverse correlation between the strength of the material and the cracks which grow inside it—both the maximum crack and the one that sets in instability within the system, defined to be the critical crack. >>

AA << found that the maximum and the critical crack often differ from each other unless the disorder strength is extremely low. A phase diagram on the plane of disorder vs system size demarcates between the regions where the largest crack is the most vulnerable one and where they differ from each other but still show moderate correlation. >>️

Viswakannan R.K., Subhadeep Roy. Critical crack length during fracture. Phys. Rev. E 110, 024134. Aug 26, 2024.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.110.024134

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

Keywords: gst, crack, instability, fluctuations, noise, criticality

# gst: phase transition of inertial self-propelled agents, a ‘inverse modeling’ approach.

AA << formulate and analyze a kinetic MFG (Mean-field Game) model for an interacting system of non-cooperative motile agents with inertial dynamics and finite-range interactions, where each agent is minimizing a biologically inspired cost function. >>️️

The << ‘inverse modelling’ approach is to stipulate that the collective behavior of a population of decision-making agents is a solution to a collective optimization or optimal control problem. (..) In a MFG system, the collective behavior is the result of each agent solving an optimal control problem that depends on its own state and control as well as the collective state. MFGs formulated in continuous state space and time are described by coupled set of forward-backward in time nonlinear partial differential equations (PDEs). >>

<< While standard kinetic or hydrodynamic equations used for modelling collective behavior are initial value problems (IVP or evolution PDEs), the MFG systems have a forward-backward in time structure, and hence consist of boundary value problem (BVP in time PDEs). >>

<< By analyzing the associated coupled forward-backward in time system of nonlinear Fokker-Planck and Hamilton-Jacobi-Bellman equations, (AA) obtain conditions for closed-loop linear stability of the spatially homogeneous MFG equilibrium that corresponds to an ordered state with non-zero mean speed. Using a combination of analysis and numerical simulations, (AA) show that when energetic cost of control is reduced below a critical value, this equilibrium loses stability, and the system transitions to a traveling wave solution. >>️

️

Piyush Grover, Mandy Huo. Phase transition in a kinetic mean-field game model of inertial self-propelled agents. arXiv: 2407.18400v1 [math.OC]. Jul 25, 2024. 

https://arxiv.org/abs/2407.18400

Also: transition, wave, game, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, transition, criticality, bifurcations, wave, games

# gst: attractive-repulsive interaction in coupled qu-oscillators, when a symmetry-breaking state could be a prominent state.

AA << have explored the role of attractive repulsive coupling in shaping the collective behavior of coupled oscillators in the quantum domain. >>

<< A direct simulation (..) showed a symmetry breaking transition from quantum limit cycle to quantum oscillation death state with increasing coupling strength. >>️

<< This is in contrast to the quantum symmetry-breaking transitions reported earlier where inhomogeneity emerges from the homogeneous steady state. >>️

<< The phenomenon is general as it occurs at both weak and deep quantum regime. Specially, in the deep quantum regime where quantum noise is strong, yet it can not wash out the inhomogeneous state indicating that the symmetry-breaking state is indeed a prominent state. >>️️

Bulti Paul, Biswabibek Bandyopadhyay, Tanmoy Banerjee. Attractive-repulsive interaction in coupled quantum oscillators. arXiv: 2408.12972v1 [quant-ph]. Aug 23, 2024.

https://arxiv.org/abs/2408.12972

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

Keywords: gst, transition, symmetry-breaking transition, noise, attractive-repulsive interaction, coupled qu-oscillator

# gst: symmetry breaking and️ ️hyperuniformity in low-dimensional systems caused by inhomogeneous oscillatory driving forces.

<< The driving forces of chiral active particles and deformations of cells are often modeled by spatially inhomogeneous but temporally periodic driving forces. Such inhomogeneous oscillatory driving forces have only recently been proposed in the context of active matter, and their effects on the systems are not yet fully understood. >>️

AA << theoretically study the impact of spatially inhomogeneous oscillatory driving forces on continuous symmetry breaking. (They) first analyze the linear model for the soft modes in the ordered phase to derive the lower critical dimension of the model, and then analyze the spherical model to investigate more detailed phase behaviors.  >>

<< Interestingly, (their) analysis reveals that symmetry breaking occurs even in one and two dimensions, where the Hohenberg-Mermin-Wagner theorem prohibits continuous symmetry breaking in equilibrium. Furthermore, fluctuations of conserved quantities, such as density, are anomalously suppressed in the long-wavelength, i.e., show hyperuniformity. >>️️

Harukuni Ikeda, Yuta Kuroda. Continuous symmetry breaking of low-dimensional systems driven by inhomogeneous oscillatory driving forces. Phys. Rev. E 110, 024140. Aug 29, 2024.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.110.024140

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

Keywords: gst, transition

# gst: apropos of 'filamentous' and 'fibrous' scenarios, criticality enhances the reinforcement of disordered networks by rigid inclusions.

<< The mechanical properties of biological materials are spatially heterogeneous. Typical tissues are made up of a spanning fibrous extracellular matrix in which various inclusions, such as living cells, are embedded. >>️

<< Recent work has shown that, in isolation, such networks exhibit unusual viscoelastic behavior indicative of an underlying mechanical phase transition controlled by network connectivity and strain. How this behavior is modified when inclusions are present is unclear. >>

AA << present a theoretical and computational study of the influence of rigid inclusions on the mechanics of disordered elastic networks near the connectivity-controlled central force rigidity transition. >>️

<< Combining scaling theory and coarse-grained simulations, (AA) predict and confirm an anomalously strong dependence of the composite stiffness on inclusion volume fraction, beyond that seen in ordinary composites. (..) this enhancement is a consequence of the interplay between inter-particle spacing and an emergent correlation length, leading to an effective finite-size scaling imposed by the presence of inclusions. >>

AA << show that this enhancement is a consequence of the interplay between inter-particle spacing and an emergent correlation length, leading to an effective finite-size scaling imposed by the presence of inclusions. >>️

AA << discuss potential experimental tests and implications for (their)  predictions in real systems. >>

️

Jordan L. Shivers, Jingchen Feng, Fred C. MacKintosh. Criticality enhances the reinforcement of disordered networks by rigid inclusions. arXiv:  2407.19563v1 [cond-mat.soft]. Jul 28, 2024. 

https://arxiv.org/abs/2407.19563

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

Keywords: gst, network, transition, disorder, elasticity, rigidity, criticality, bifurcations

# gst: dynamics of small droplets in turbulent multiphase flows

AA << show unambiguously that the formation of small droplets is governed by the internal dynamics which occurs during the breakup of large drops and that the high vorticity and the extreme dissipation associated to these events are the consequence and not the cause of the breakup. >>️

M. Crialesi-Esposito, G. Boffetta, L. Brandt, et al. How small droplets form in turbulent multiphase flows. Phys. Rev. Fluids 9, L072301. Jul 29, 2024. 

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.9.L072301

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

Keywords: gst, drop, droplet, droploid,  bubble, transition, turbulence, intermittency

# gst: distance to criticality in unknown noise

<< real-world systems are often corrupted by unknown levels of noise that can distort (..) temporal signatures. Here (AA) aim to develop noise-robust indicators of the distance to criticality (DTC) for systems affected by dynamical noise in two cases: when the noise amplitude is either fixed or is unknown and variable across recordings. >>️

<< in the variable-noise setting, where (..) conventional indicators perform poorly, (AA) highlight new types of high-performing time-series features and show that their success is accomplished by capturing the shape of the invariant density (which depends on both the DTC and the noise amplitude) relative to the spread of fast fluctuations (which depends on the noise amplitude). (AA) introduce a new high-performing time-series statistic, the rescaled autodensity (RAD). >>️

Brendan Harris, Leonardo L. Gollo, Ben D. Fulcher. Tracking the Distance to Criticality in Systems with Unknown Noise. Phys. Rev. X 14, 031021. Aug 8, 2024.

https://journals.aps.org/prx/abstract/10.1103/PhysRevX.14.031021

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

Keywords: gst, criticality, bifurcation, noise, transition

# gst: existence of hidden metastable states, bifurcations of inflating balloons and interacting hysterons.

AA << consider a system of connected rubber balloons that can be described by a Preisach model of noninteracting hysterons under pressure control but for which the hysterons become coupled under volume control. >>

<< Changes in the transition graphs turn out to be related to changes in the topology of the configuration space of the balloons, providing a particularly geometric view of how transition graphs can be designed, as well as additional information on the existence of hidden metastable states. This class of systems is more general than just balloons. >>️

Gentian Muhaxheri and Christian D. Santangelo. Bifurcations of inflating balloons and interacting hysterons. Phys. Rev. E 110, 024209. Aug 16, 2024.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.110.024209

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

Keywords: gst, balloons, bifurcations, hysteresis, hysterons, transition

# gst: spontaneous bouncing, trampolining, and hovering behaviors of a levitating water droplet without constraints.

<< The levitating Leidenfrost (LF) state of a droplet on a heated substrate is often accompanied by fascinating behaviors such as star-shaped deformations, self-propulsion, bouncing, and trampolining. These behaviors arise due to the vapor flow instabilities at the liquid-vapor interface beneath the droplet at sizes typically comparable to the capillary length scale of the liquid. >>

AA << report on the spontaneous bouncing, trampolining, and hovering behavior of an unconstrained LF water droplet. (..) the water droplet exhibits an increase in bouncing height at specific radii with intermittent reduction in the height of bounce leading to a quiescent LF state. The reemergence of the trampolining behavior from the quiescent hovering state without any external forcing is observed at sizes as low as 0.1 times the capillary length. (AA) attribute the droplet bouncing behavior to the dynamics of vapor flow beneath the LF droplet. >>

AA << propose that the trampolining behavior of the droplet at specific radii is triggered by harmonic and subharmonic resonance between the natural frequency of the vapor layer and Rayleigh frequency of the droplet. This proposed mechanism of resonance-driven trampolining of LF droplets is observed to be applicable for different liquids irrespective of the initial volume and substrate temperatures, thus indicating a universality of the behavior. (AA) attribute the intermittent trampolining events to the change in the natural frequency of the droplet and the vapor layer due to evaporative mass loss. >>

Pranjal Agrawal, Susmita Dash. Reemergence of Trampolining in a Leidenfrost Droplet. arXiv: 2408.02335v1 [physics.flu-dyn]. Aug 5, 2024. 

https://arxiv.org/abs/2408.02335

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

Keywords: gst, drop, droplet, droploid, behav, behaviour

# gst: apropos of 'normal' (jazzy?) codes, bacteria encode hidden, free-floating genes outside their genome.

AA << show that bacteria break that rule and can create free-floating and ephemeral genes, raising the possibility that similar genes exist outside of our own genome. >>️

<< What this discovery upends is the notion that the chromosome has the complete set of instructions that cells use to produce proteins, (..) We now know that, at least in bacteria, there can be other instructions not preserved in the genome that are nonetheless essential for cell survival. (..) The DNA molecule is a fully functioning, free-floating, transient gene. >> Samuel Sternberg. 

Bacteria Encode Hidden Genes Outside Their Genome—Do We? Columbia University Irving Medical Center. Aug 8, 2024. 

https://www.cuimc.columbia.edu/news/bacteria-encode-hidden-genes-outside-their-genome-do-we   

Stephen Tang, Valentin Conte, et al. De novo gene synthesis by an antiviral reverse transcriptase. Science. doi: 10.1126/ science.adq0876. Aug 8, 2024. 

https://www.science.org/doi/10.1126/science.adq0876

Also: 

codes https://flashontrack.blogspot.com/search?q=codes

DNA  https://flashontrack.blogspot.com/search?q=dna

RNA  https://flashontrack.blogspot.com/search?q=rna

CRISPR  https://flashontrack.blogspot.com/search?q=crispr

normal, jazz, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, codes, dna, rna, crispr, normal, jazz

# gst: networks of pendula with diffusive interactions, chaotic regime seems to emerge at low energies.

AA << study a system of coupled pendula with diffusive interactions, which could depend both on positions and on momenta. The coupling structure is defined by an undirected network, while the dynamic equations are derived from a Hamiltonian; as such, the energy is conserved. >>️

<< The behaviour observed showcases a mechanism for the appearance of chaotic oscillations in conservative systems. For Hamiltonians with two degrees of freedom, it has been shown how chaos can emerge near a saddle-centre equilibrium possessing a homoclinic orbit. (AA) have seen that higher-dimensional systems having mixed equilibria, i.e., generalisations of a saddle-center where the eigenvalues are only imaginary and reals, also show chaotic behaviour close to those points.  >>️

AA << complement the analysis with some numerical simulations showing the interplay between bifurcations of the origin and transitions to chaos of nearby orbits. A key feature is that the observed chaotic regime emerges at low energies. >>

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Riccardo Bonetto, Hildeberto Jardón-Kojakhmetov, Christian Kuehn. Networks of Pendula with Diffusive Interactions. arXiv: 2408.02352v1 [math.DS]. Aug 5, 2024.

https://arxiv.org/abs/2408.02352

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

Keywords: gst, pendulum, network, transition, chaos, bifurcation

# gst: emergent chirality in active rotation even with spontaneous chiral symmetry breaking.

<< Collective cell dynamics play a crucial role in many developmental and physiological contexts. While two-dimensional (2D) cell migration has been widely studied, how three-dimensional (3D) geometry and topology interplay with collective cell behavior to determine dynamics and functions remains an open question. >>️

<< Using murine pancreas-derived organoids as a model system, (AA) find that epithelial spheres exhibit persistent rotation, rotational axis drift, and rotation arrest. Using a 3D vertex model, (they) demonstrate how the combined action of traction force and polarity alignment can account for these distinct rotational dynamics near a solid to flow transition. Furthermore, (their) analysis shows that the spherical tissue rotates as an active solid occasionally switching to a flowing state and exhibits spontaneous chiral symmetry breaking. >>️

Tzer Han Tan, Aboutaleb Amiri, et al. Emergent chirality in active solid rotation of pancreas spheres. PRX Life 2, 033006. Aug 8, 2024.

https://journals.aps.org/prxlife/abstract/10.1103/PRXLife.2.033006

AA << say their work shows how symmetry-breaking processes in living active matter can be induced by the interplay of geometry, topology, and collective dynamics. >>️

Charles Day. Emergent Chirality in Active Rotation. Physics 17, s102. Aug 8, 2024. 

https://physics.aps.org/synopsis-for/10.1103/PRXLife.2.033006 

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

Keywords: gst, transition, chiral, chiral symmetry breaking 

# gst: tracking criticality in unknown noise

<< Many real-world systems undergo abrupt changes in dynamics as they move across critical points, often with dramatic and irreversible consequences. >>️

AA << aim to develop noise-robust indicators of the distance to criticality (DTC) for systems affected by dynamical noise in two cases: when the noise amplitude is either fixed or is unknown and variable across recordings. (They) present a highly comparative approach to this problem that compares the ability of over 7000 candidate time-series features to track the DTC in the vicinity of a supercritical Hopf bifurcation. >>️

<< in the variable-noise setting, where these conventional indicators perform poorly, (AA) highlight new types of high-performing time-series features and show that their success is accomplished by capturing the shape of the invariant density (which depends on both the DTC and the noise amplitude) relative to the spread of fast fluctuations (which depends on the noise amplitude). >>

AA << introduce a new high-performing time-series statistic, the rescaled autodensity (RAD), that combines these two algorithmic components. >>️

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Brendan Harris, Leonardo L. Gollo, Ben D. Fulcher. Tracking the Distance to Criticality in Systems with Unknown Noise. Phys. Rev. X 14, 031021. Aug 8, 2024.

https://journals.aps.org/prx/abstract/10.1103/PhysRevX.14.031021

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

Keywords: gst, noise, brain, mouse visual cortex