Translate

lunedì 23 dicembre 2024

# 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.

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

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


domenica 22 dicembre 2024

# 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.

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

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.️

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 ... >>️


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

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


venerdì 20 dicembre 2024

# 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.

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

Keywords: gst, chimera, network, transition


giovedì 19 dicembre 2024

# 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. 

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

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

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


martedì 17 dicembre 2024

# 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.

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

Keywords: gst, vortex, dance 


sabato 14 dicembre 2024

# 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.

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

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


venerdì 13 dicembre 2024

# 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.


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

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


mercoledì 11 dicembre 2024

# 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. 

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

Keywords: gst, fluctuations, turbulence, transition 



lunedì 9 dicembre 2024

# 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. 

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

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

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


domenica 8 dicembre 2024

# 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. 

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

Keywords: gst, drops, bubbles, instability, transition


venerdì 6 dicembre 2024

# 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.

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

Keywords: gst, drop, droplet, droploid, transition


giovedì 5 dicembre 2024

# 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.

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

Keywords: gst, bubble, turbulence, intermittency


mercoledì 4 dicembre 2024

# 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. 

<< 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):

(-) outcomes

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).


lunedì 2 dicembre 2024

# 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.

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

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


sabato 30 novembre 2024

# life: apropos of interactions, “attacks” and “circling” of Zebrafish in the dynamics of dominance.


<< While two-body fighting behavior occurs throughout the animal kingdom to settle dominance disputes, important questions such as how the dynamics ultimately lead to a winner and loser are unresolved. Here (AA) examine fighting behavior at high resolution in male zebrafish. >>️

<< In the body point trajectories (AA) find a spectrum of timescales which (they) use to build informative joint coordinates consisting of relative orientation and distance. (AA) use the distribution of these coordinates to automatically identify fight epochs, and (then) demonstrate the postfight emergence of an abrupt asymmetry in relative orientations—a clear and quantitative signal of hierarchy formation. >>

AA << identify short-time, multi-animal behaviors as clustered transitions between joint configurations, and show that fight epochs are spanned by a subset of these clusters, which (they) denote as maneuvers. The resulting space of maneuvers is rich but interpretable, including motifs such as “attacks” and “circling.” In the longer-time dynamics of maneuver frequencies (AA) find differential and changing strategies, including that the eventual loser attacks more often towards the end of the contest. >>️

AA << results suggest a reevaluation of relevant assessment models in zebrafish, while our approach is generally applicable to other animal systems. >>️
Liam O'Shaughnessy, Tatsuo Izawa, et al. Dynamics of Dominance in Interacting Zebrafish. PRX Life 2, 043006. Oct 25, 2024.


Keywords: gst, behavior, behaviour


venerdì 29 novembre 2024

# gst: fluid stretching and compression to control (chemical) waves

<< Oscillatory kinetics coupled to diffusion can produce traveling waves as observed in physical, chemical, and biological systems. (AA) show experimentally that the properties of such waves can be controlled by fluid stretching and compression in a hyperbolic flow. >>
<< Localized packet waves consisting in a train of parallel waves can develop due to a balance between diffusive broadening and advective compression along the unstable manifold. At a given distance from the stagnation point, the parallel waves transform into planelike waves and smeared waves where the transverse parabolic flow profile disturbs the patterns in the gap width. >> 

<< Once a wave packet has been obtained, it imprints a privileged direction that is maintained even if the compression rate is decreased. The width of the wave packet then scales inversely with the compression rate. >>️

S. Izumoto, D. M. Escala, et al. Control of Chemical Waves by Fluid Stretching and Compression. Phys. Rev. Lett. 133, 218001. Nov 21, 2024. 


Keywords: gst, waves


mercoledì 27 novembre 2024

# gst: when a pseudo pyramid cyclically flips; (lab) icebergs melt down and flip out


AA << study laboratory-scale icebergs that freely float and melt, where direct visualizations show interesting and interconnected changes in the shape of the ice, its posture, and the flows of the surrounding water. >>️

<< Ice in nature is dynamic at all scales, from glacial sheets that deform and flow to icebergs that melt down and capsize. For the latter, much of the ice and much of the action is unseen beneath the surface. >>️

<< Here (AA) study laboratory-scale icebergs that freely float and melt, where direct visualizations show interesting and interconnected changes in the shape of the ice, its posture, and the flows of the surrounding water. >>️

Bobae Johnson, Zihan Zhang, et al. Lab icebergs melt down and flip out. Phys. Rev. Fluids 9, 110510. Nov 22, 2024.

Bobae Johnson, Steven Zhang, et al. P0011: Lab icebergs melt down and flip out. 76th Annual Meeting of the APS Division of Fluid Dynamics. Nov 19-21, 2023. 

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

Keywords: gst, transition


martedì 26 novembre 2024

# evol: nomads, a whole story of human evolution.


<< In pursuit of knowledge, the evolution of humanity ranks with the origins of life and the universe. And yet, except when an exciting find hits the headlines, palaeoanthropology and its related fields have gained far less scientific support and funding – particularly for scientists and institutions based in the African countries where so many landmark discoveries have occurred. >>️

<< Even the term “human” is arguable. Many scholars reserve it for modern humans like us, even though we have Neanderthal genes and they shared at least 90% of our hominin history from its beginnings around 8 million years ago. The essence of hominin evolution ever since has been gradual change, with occasional rapid phases. The record of evolution in our own genus, Homo, is already full enough to show we cannot separate ourselves with hard lines. >>️

<< Nonetheless, there is enough consensus to thread the story of human evolution all the way from early apes to modern humanity. Most of this story centres on Africa, of course, where countries such as Kenya, South Africa and Ethiopia are rightly proud of their heritage as “cradles of humankind” – providing many of their schoolchildren with a much fuller answer then those in the west to this deceptively simple question: how did we get here? >>️

John Gowlett. The whole story of human evolution – from ancient apes via Lucy to us – in one long read. theconversation.com. Nov 25, 2024.

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

Keywords: Nomads, evolution


lunedì 25 novembre 2024

# gst: apropos of dances, drops that dance following snake- and ouroboros-shaped trajectories on lubricated surfaces.


<< Recently, (AA) observed a curious breath figure pattern when water condenses on solid surfaces coated with a thin lubricant oil film. Water drops of various sizes, ranging from tens of microns to several millimetres, start to perform a self-avoiding, serpentinelike dance. As the drop moves, it consumes smaller droplets along its path, converting interfacial energy into kinetic energy to sustain its motion. These self-avoiding drops preferentially avoid crossing their own paths as well as the paths of other drops; they can only intersect their previous paths once sufficient recondensation has occurred. This self-avoiding behavior arises because the previous path (..) contains little to no water content to fuel self-propulsion, so the drops continually seek areas with higher local water content. >>️

<< This intricate serpentine dance is driven by short-range interactions between droplets, mediated by overlapping menisci, similar to the Cheerios effect. Remarkably, long-range order spontaneously emerges from these short-range interactions, with the collective motion exhibiting self-similarity—breath figure patterns appear roughly similar across different scales. >>

<< The serpentine motions of the drops, which can span distances many times their diameters, eventually deplete the local lubricant film, causing a transition from serpentine to circular motion. This circular motion can be seen as a unique form of serpentine motion occurring in lubricant-poor regions. As the drops move, they continually redistribute the lubricant across the substrate, leading to a dynamic interplay between serpentine and circular motions. This ongoing redistribution can be visualized by illuminating the surface with diffused white light and capturing the resulting interference patterns with a digital camera. Variations in lubricant thickness produce different hues, creating a vibrant, colorful canvas and an intricate dance floor for the condensing drops. >>️

<< The phenomenon described in (AA) paper represents a fascinating example of active matter driven by condensation, rather than the more commonly observed chemical reactions or Marangoni effects. >>

Marcus Lin, Fauzia Wardani, Dan Daniel. Dancing drops on lubricated surfaces. Phys. Rev. Fluids 9, 110504. Nov 22, 2024.

Marcus Lin, Solomon Adera, Joanna Aizenberg, Yao Xi, Dan Daniel. V0030: Serpents and Ouroboros: Emergent collective motion of condensate droplets. 76th Annual Meeting of the APS Division of Fluid Dynamics. Nov 19-21, 2023.

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

Keywords: gst, drop, droplet, droploid, dance


venerdì 22 novembre 2024

# gst: protected chaos in a topological lattice.

<< The erratic nature of chaotic behavior is thought to erode the stability of periodic behavior, including topological oscillations. However, (AA) discover that in the presence of chaos, non-trivial topology not only endures but also provides robust protection to chaotic dynamics within a topological lattice hosting non-linear oscillators. >>

<< Despite the difficulty in defining topological invariants in non-linear settings, non-trivial topological robustness still persists in the parametric state of chaotic boundary oscillations. (AA) demonstrate this interplay between chaos and topology by incorporating chaotic Chua's circuits into a topological Su-Schrieffer-Heeger (SSH) circuit. >>

<< By extrapolating from the linear limit to deep into the non-linear regime, (AA) find that distinctive correlations in the bulk and edge scroll dynamics effectively capture the topological origin of the protected chaos. (Their)  findings suggest that topologically protected chaos can be robustly achieved across a broad spectrum of periodically-driven systems, thereby offering new avenues for the design of resilient and adaptable non-linear networks. >>️

Haydar Sahin, Hakan Akgün, et al. Protected chaos in a topological lattice. arXiv: 2411.07522v1 [cond-mat.mes-hall]. Nov 12, 2024.

Also: chaos, random, instability, transition, network, ai (artificial intell), in https://www.inkgmr.net/kwrds.html 

Keywords: gst, chaos, random,  instability, transition, network, AI, Artificial Intelligence


giovedì 21 novembre 2024

# 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. 

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


martedì 19 novembre 2024

# 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. 

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

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

Keywords: gst, transition, singularity, bifurcation


lunedì 18 novembre 2024

# 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.

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

Keywords: gst, transition, instability, crack 


sabato 16 novembre 2024

# 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.

Also: chimera, instability, chaos, network, in 

Keywords: gst, chimera, instability, chaos, network


lunedì 11 novembre 2024

# 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. 

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

Keywords: gst, bubble, bubble collapse 


sabato 9 novembre 2024

# 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. 

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

Keywords: life, Donald, potus, potus race


venerdì 8 novembre 2024

# 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. 

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

Keywords: gst, turbulence, vortex


giovedì 7 novembre 2024

# 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. 

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. 

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

Keywords: gst, brain, evolution


martedì 5 novembre 2024

# 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. 

Also: NaN 'Not a Number'. In: Onda pneica. Apr 10, 2005 (quasi-stochastic poetry) https://inkpi.blogspot.com/2005/04/1694b-onda-pneica.htmlnan(). 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


domenica 3 novembre 2024

# 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.

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

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

sabato 2 novembre 2024

# 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. 

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

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


venerdì 1 novembre 2024

# 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.

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

Keywords: gst, fracture, crack, behavior


mercoledì 30 ottobre 2024

# 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. 

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.


martedì 29 ottobre 2024

# 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. 

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


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, ... )


domenica 27 ottobre 2024

# 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.

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

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


venerdì 25 ottobre 2024

# 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.

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


giovedì 24 ottobre 2024

# 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.

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

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


martedì 22 ottobre 2024

# 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. 

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

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


sabato 19 ottobre 2024

# 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. 

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

Keywords: gst, particle, transition 



venerdì 18 ottobre 2024

# 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.

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

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

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


mercoledì 16 ottobre 2024

# 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.

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. 


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


lunedì 14 ottobre 2024

# 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.

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

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


domenica 13 ottobre 2024

# 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.


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


venerdì 11 ottobre 2024

# 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. 

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. 

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

Also

Also (quasi-stochastic poetry): 

Keywords: evolution, codes, DNA, RNA


giovedì 10 ottobre 2024

# 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.

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



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


martedì 8 ottobre 2024

# 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.

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

Keywords: gst, particle, turbulence