# gst: instability and self-propulsion of flexible autophoretic filaments; it was observed distinct swimming modes, steadily translating "U" and metastable rotating "S" shapes.

<< ️Over the past decade, autophoretic colloids have emerged as a prototypical system for studying self-propelled motion at microscopic scales, with promising applications in microfluidics, micro-machinery, and therapeutics. Their motion in a viscous fluid hinges on their ability to induce surface slip flows that are spatially asymmetric, from self-generated solute gradients. >>

<<️ Here, (AA) demonstrate theoretically that a straight elastic filament with homogeneous surface chemical properties -- which is otherwise immotile -- can spontaneously achieve self-propulsion by experiencing a buckling instability that serves as the symmetry-breaking mechanism. Using efficient numerical simulations, (They) characterize the nonlinear dynamics of the elastic filament and show that, over time, it attains distinct swimming modes such as a steadily translating "U" shape and a metastable rotating "S" shape when semi-flexible, and an oscillatory state when highly flexible. >>

Ursy Makanga, Akhil Varma, Panayiota Katsamba. Instability and self-propulsion of flexible autophoretic filaments. arXiv: 2509.10153v1 [cond-mat.soft]. Sep 12, 2025.

https://arxiv.org/abs/2509.10153

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

Keywords: gst, colloids, autophoretic colloids, elasticity, instability, buckling instability, symmetry-breaking mechanisms, self-propulsion, transitions.

# brain: network representations reveal structured uncertainty in music.

<< ️Music, as a structured yet perceptually rich experience, can be modeled as a network to uncover how humans encode and process auditory information. While network-based representations of music are increasingly common, the impact of feature selection on structural properties and cognitive alignment remains underexplored. >>

<< ️In this study, (AA) evaluated eight network models, each constructed from symbolic representations of piano compositions using distinct combinations of pitch, octave, duration, and interval, designed to be representative of existing approaches in the literature. By comparing these models through topological metrics, entropy analysis, and divergence with respect to inferred cognitive representations, (They) assessed both their structural and perceptual efficiency.  >>

<< ️(AA) findings reveal that simpler, feature-specific models better match human perception, whereas complex, multidimensional representations introduce cognitive inefficiencies. These results support the view that humans rely on modular, parallel cognitive networks--an architecture consistent with theories of predictive processing and free energy minimization. >>

<< ️Moreover, (AA) find that musical networks are structurally organized to guide attention toward transitions that are both uncertain and inferable. The resulting structure concentrates uncertainty in a few frequently visited nodes, creating local entropy gradients that alternate between stable and unpredictable regions, thereby enabling the expressive dynamics of tension and release that define the musical experience. >> 

<< ️These findings show that network structures make the organization of uncertainty in music observable, offering new insight into how patterned flows of expectation shape perception, and open new directions for studying how musical structures evolve across genres, cultures, and historical periods through the lens of network science. >>

Lluc Bono Rosselló, Robert Jankowski, et al. Network representations reveal structured uncertainty in music. arXiv: 2509.14053v1 [physics.soc-ph]. 17 Sep 17,  2025.

https://arxiv.org/abs/2509.14053

Also: brain, music, jazz, perception, uncertainty, network, in https://www.inkgmr.net/kwrds.html 

Keywords: brain, music, jazz, perception, auditory information, networks, structural properties, cognitive alignment, uncertainty, uncertain-- inferable transitions.

# gst: extreme vertical drafts as drivers of Lagrangian dispersion in stably stratified turbulent flows.

<< ️The dispersion of Lagrangian particle pairs is a fundamental process in turbulence, with implications for mixing, transport, and the statistical properties of particles in geophysical and environmental flows. While classical theories describe pair dispersion through scaling laws related to energy cascades, extreme events in turbulent flows can significantly alter these dynamics. This is especially important in stratified flows, where intermittency manifests itself also as strong updrafts and downdrafts. >>

<< ️In this study, (AA) investigate the influence of extreme events on the relative dispersion of particle pairs in stably stratified turbulence. Using numerical simulations (They) analyze the statistical properties of pair separation across different regimes, and quantify deviations from classical Richardson scaling. (Their) results highlight the role of extreme drafts in accelerating dispersion. >>

Christian Reartes, Pablo D. Mininni, Raffaele Marino. Extreme vertical drafts as drivers of Lagrangian dispersion in stably stratified turbulent flows. arXiv: 2509.12962v1 [physics.flu-dyn]. Sep 16, 2025.

https://arxiv.org/abs/2509.12962

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

Keywords: gst, turbulence, stratified turbulence,  intermittency, chaos, transitions, particles, extreme events, stratified flows, accelerating dispersion.

# behav: two distinct attentional priorities guide exploratory and exploitative gaze in parallel

<< Gaze is directed to visual objects that are informative, reward-predictive, or novel. These gaze preferences may reflect the parallel influence of two separable attention systems: Exploratory attention prioritizing uncertainty and exploitative attention prioritizing learned information about reward. >>

<< (AA) tested this hypothesis in nonhuman primates learning feature-based attention to objects that had either previously learned reward associations or were novel. The reward history of features slowed down learning by attracting fixations of non-rewarded distractors that were previously targets. This reward history bias persisted in fixations used to choose objects even after choice accuracy stabilized. In contrast, fixational sampling that preceded a choice showed negligible history biases that were overcome quickly in favor of wider exploratory sampling. >>

<< Quantifying the exploratory value object features with a Parallel Belief States model of attention confirmed that exploratory fixational sampling was unaffected by reward history, while exploitative fixations that committed to a decision showed persistent target history biases. These findings suggest that gaze is guided by two separable attentional priorities in parallel. Exploratory attention prioritizes uncertain items and instantiates information sampling, while exploitative attentional priority guides gaze to current and previously goal-relevant features. >>

Xuan Wen, Alireza Seyed Hassani, et al. Two Distinct Attentional Priorities Guide Exploratory and Exploitative Gaze in Parallel. biorxiv.org. Sep 20, 2025.

https://www.biorxiv.org/content/10.1101/2025.09.20.677503v1

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

Keywords: brain, behavior, cognition, attentional control, information seeking,  exploratory-- exploitative attentions.

# gst: role of evaporation in stability of foam films and foams.

<< ️Understanding the stability of foam films and foams remains a challenge, despite the considerable efforts provided by the scientific community to refine their physical descriptions. This persistent difficulty underscores the interplay of various complex factors. Recently, the role of evaporation has attracted attention for its dual impact: it can either enhance stability or accelerate bursting. >>

<< ️To depict a comprehensive overview on soapy objects, (AA) propose first a short description on the evaporation of drops to present some key results on the evaporation-induced cooling and the consequences on the internal flows generated by Marangoni effects. Then, (They) review the literature on foam films and foams, examining three distinct systems: pure liquids, nonvolatile, and volatile surface active molecules. ️(AA) show that evaporation of foam films and foams can lead to significant variations of temperature. In conclusion, (They) identify a series of open questions and suggest potential research pathways to address these challenges. >>

François Boulogne, Emmanuelle Rio. Role of evaporation in stability of foam films and foams. Phys. Rev. E 112, 031001. Sep 9, 2025.

https://journals.aps.org/pre/abstract/10.1103/52dh-hnnx 

arXiv: 2509.08958v1 [cond-mat.soft]. Sep 10, 2025. 

https://arxiv.org/abs/2509.08958

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

Keywords: gst, bubbles, drops, evaporation. 

# gst: spiral defect chaos with intermittency increases mean termination time

<< ️Cardiac models are examples of excitable systems and can support stable spiral waves. For certain parameter values, however, these spiral waves can become unstable, resulting in spiral defect chaos (SDC), characterized by the continuous creation and annihilation of spiral waves and thought to underlie atrial fibrillation. During SDC, the number of spiral waves fluctuates and drops to zero at termination. >>

<< ️In this work, (AA) demonstrate that varying a single parameter allows the system to transition from SDC to a single spiral wave, passing through an intermediate regime of intermittency. In such intermittent dynamics, intervals of SDC are sandwiched between non-SDC intervals during which the number of spiral waves remains small and constant. (They) quantify this intermittency and show that the mean termination time increases significantly as the control parameter approaches values for which a single spiral wave is stable. >>

<<  In addition, (AA) observe that quasistable spiral waves may intermittently persist in part of the computational domain, while the rest of the domain exhibits SDC. >> 

Mahesh Kumar Mulimani, Wouter-Jan Rappel. Spiral defect chaos with intermittency increases mean termination time. Phys. Rev. E 112, 034203. Sep 3, 2025.

https://journals.aps.org/pre/abstract/10.1103/bwpl-qqyl

arXiv: 2505.06427v1 [nlin.CD]. May 9,  2025

https://arxiv.org/abs/2505.06427

Also: waves, intermittency, vortex, chaos, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, waves, spiral & scroll waves, intermittency, vortex, chaos, spiral defect chaos.

# astro: could we observe an exploding black hole in the near future?

<< ️Observation of gamma rays from an exploding black hole would provide strong evidence for primordial black holes, the first direct evidence of Hawking radiation, and definitive information on the particles present in nature. However, indirect constraints suggest that direct observation of an exploding Schwarzschild black hole at current or upcoming gamma ray observatories is implausible. >>

<< ️(AA) introduce a dark-QED (Quantum Electrodynamics) toy model consisting of a dark photon and a heavy dark electron. In this scenario a population of light primordial black holes charged under the dark 𝑢⁡(1) symmetry can become quasiextremal, so they survive much longer than if they were uncharged, before discharging and exhibiting a Schwarzschild-like final explosion. (They) show that the answer is “yes,” in this scenario the probability of observing an exploding black hole over the next 10 years could potentially be over 90%. >>

Michael J. Baker, Joaquim Iguaz Juan, et al. Could We Observe an Exploding Black Hole in the Near Future? Phys. Rev. Lett. 135, 111002. Sep 10, 2025. 

https://journals.aps.org/prl/abstract/10.1103/nwgd-g3zl

Marric Stephens. Dark Charge Could Make Exploding Black Holes More Common. (Synopsis). Physics 18, s112. Sep 10, 2025. 

https://link.aps.org/doi/10.1103/Physics.18.s112

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

Keywords: black holes, evaporating black holes, astrophysics.