# gst: dynamics of swarmalators in the presence of a contrarian.

<< Swarmalators are entities that combine the swarming behavior of particles with the oscillatory dynamics of coupled phase oscillators and represent a novel and rich area of study within the field of complex systems. >>

<< Unlike traditional models that treat spatial movement and phase synchronization separately, swarmalators exhibit a unique coupling between their positions and internal phases, leading to emergent behaviors that include clustering, pattern formation, and the coexistence of synchronized and desynchronized states, etc. >>

This AA paper << presents a comprehensive analysis of a two-dimensional swarmalator model in the presence of a predatorlike agent that (They) call a contrarian. The positions and the phases of the swarmalators are influenced by the contrarian and (They)  observe the emergence of intriguing collective states. >>

AA find << that swarmalator phases are synchronized even with negative coupling strength when their interaction with the contrarian is comparatively strong. Through a combination of analytical methods and simulations, (They) demonstrate how varying these parameters can lead to transitions between different collective states. >>

Gourab Kumar Sar, Sheida Ansarinasab, et al. Dynamics of swarmalators in the presence of a contrarian. Phys. Rev. E 111, 014209. Jan 7, 2025.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.111.014209 

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

Keywords: gst, swarm, swarmalators, transitions, behavior, behaviour

# 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.

https://journals.aps.org/prxlife/abstract/10.1103/PRXLife.2.043006

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

Keywords: gst, behavior, behaviour

# 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: 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: 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

# behav: swarms and hybrids, an approach to create and control collective motions (on demand)

AA << demonstrate that it is possible to generate coordinated structures in collective behavior at desired moments with intended global patterns by fine-tuning an inter-agent interaction rule. (Their) strategy employs deep neural networks, obeying the laws of dynamics, to find interaction rules that command desired collective structures. The decomposition of interaction rules into distancing and aligning forces, expressed by polynomial series, facilitates the training of neural networks to propose desired interaction models. Presented examples include altering the mean radius and size of clusters in vortical swarms, timing of transitions from random to ordered states, and continuously shifting between typical modes of collective motions. This strategy can even be leveraged to superimpose collective modes, resulting in hitherto unexplored but highly practical hybrid collective patterns, such as protective security formations. >>

Dongjo Kim, Jeongsu Lee, Ho-Young Kim. Navigating the swarm: Deep neural networks command emergent behaviours. arXiv: 2407.11330v1 [cs.NE]. Jul 16, 2024.️

https://arxiv.org/abs/2407.11330

Also: swarm, flock, behav, AI (artificial intell), in https://www.inkgmr.net/kwrds.html 

Keywords: behav, swarm, flock, AI, artificial intelligence 

# ethno: apropos of Nomads, an Aboriginal ritual passed down for 500 generations.

AA << excavated at Cloggs Cave near Buchan, in the foothills of the high country near the Snowy River in East Gippsland, Victoria. >>️

<< What (AA) found was extraordinary. Under the low, subdued light in the depth of the cave, buried under layers of ash and silt, two unusual fireplaces were revealed by the tip of the trowel. They each contained a single trimmed stick associated with a tiny patch of ash. >>️

<< The role of these fireplaces in ritual

Local 19th-century ethnography has good descriptions of such fireplaces, so (AA) know they were made for ritual practices performed by mulla-mullung, powerful GunaiKurnai medicine men and women. >>️

<< The Kurnai practice is to fasten the article [something that belonged to the victim] to the end of a throwing stick, together with some eaglehawk feathers, and some human or kangaroo fat. The throwing stick is then stuck slanting in the ground before a fire, and it is of course placed in such a position that by-and-by it falls down. The wizard has during this time been singing his charm; as it is usually expressed, he ‘sings the man’s name,’ and when the stick falls the charm is complete. The practice still exists. >>️

<< Nowhere else on Earth have archaeological expressions of a very specific cultural practice known from ethnography, yet traceable so far back, previously been found. >>️

Russell Mullett, Ashleigh Rogers, et al. Oldest living culture: our new research shows an Indigenous ritual passed down for 500 generations. theconversation.com. Jul 1, 2024. 

https://theconversation.com/oldest-living-culture-our-new-research-shows-an-indigenous-ritual-passed-down-for-500-generations-230782

Bruno David, Russell Mullett, et al. 

Archaeological evidence of an ethnographically documented Australian Aboriginal ritual dated to the last ice age. Nat Hum Behav. doi: 10.1038/ s41562-024-01912-w. Jul 1,  2024. 

https://www.nature.com/articles/s41562-024-01912-w

Also: ethno, Nomads, gris-gris, behav, in https://www.inkgmr.net/kwrds.html 

Keywords: ethno, Nomads, gris-gris, behaviors

FonT: the image cited regarding mulla-mullung entities is very intriguing ... 

# gst: curiosity-driven search for novel behaviors.

<< One of the first exciting things to do with a new physical system is to go exploring—to tune parameters and see what unexpected behaviors the system is capable of. >>️

AA << combine active and unsupervised learning for automated exploration of nonequilibrium systems with unknown order parameters. (They) iteratively use active learning based on current order parameters to expand the library of behaviors and relearn order parameters based on this expanded library. (They) demonstrate the utility of this approach in Kuramoto models of increasing complexity. In addition to reproducing known phases, (AA) reveal previously unknown behavior and related order parameters, and demonstrate how to align search with human intuition. >>️

Martin J. Falk, Finnegan D. Roach, et al. Curiosity-driven search for novel nonequilibrium behaviors. Phys. Rev. Research 6, 033052. Jul 11, 2024. 

https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.6.033052  

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

Keywords: gst, curiosity, behav, transition

# ethno: cross-cultural comparison of rhythm priors in 15 countries.

<< Music is present in every known society but varies from place to place. What, if anything, is universal to music cognition? (AA) measured a signature of mental representations of rhythm in 39 participant groups in 15 countries, spanning urban societies and Indigenous populations. >>️

Their << results suggest a common feature of music cognition: discrete rhythm ‘categories’ at small-integer ratios. These discrete representations plausibly stabilize musical systems in the face of cultural transmission but interact with culture-specific traditions to yield the diversity that is evident when mental representations are probed across many cultures. >>️

Nori Jacoby, Rainer Polak, et al. Commonality and variation in mental representations of music revealed by a cross-cultural comparison of rhythm priors in 15 countries. Nat Hum Behav.  doi: 10.1038/ s41562-023-01800-9. March 4, 2024. 

https://www.nature.com/articles/s41562-023-01800-9 

Also: ethno, music, jazz, behav, in https://www.inkgmr.net/kwrds.html 

Keywords: ethno, music, jazz, behavior

# gst: apropos of synchronization of large bubble clouds, self-oscillating acoustic bubbles that bounce

<< Self-oscillations underlie many natural phenomena such as heartbeat, ocean waves, and the pulsation of variable stars. (..) In this study, (AA) consider two closely spaced bubbles pulsating in the kHz range in response to ultrasonic excitation. A translational bouncing motion emerges from their interaction with a much lower frequency than the bubble pulsation frequency. >>

Their analysis << reveals that the observed bubble bouncing exhibits the main features of self-oscillation, such as negative damping and the emergence of a limit cycle. These results highlight unexpected nonlinear effects in the field of microbubbles and give insights into the understanding of synchronization in large bubble clouds. >>️

Gabriel Regnault, Alexander A Doinikov, et al. Phenomenon of self-oscillation in bubble dynamics: Bouncing acoustic bubbles. arXiv: 2404.05822v1 [physics.flu-dyn]. Apr 8, 2024.

https://arxiv.org/abs/2404.05822

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

Keywords: gst, bubble, self-oscillation, bouncing, behavior, collective behavior, bouncing motion, synchronization

# gst: apropos of collective behaviors, a visual model to reproduces swarming, schooling, and milling.

<< Animal collective behavior is often modeled with self-propelled particles, assuming each individual has “omniscient” knowledge of its neighbors. Yet, neighbors may be hidden from view and we do not know the effect of this information loss. To address this question, (AA) propose a visual model of collective behavior where each particle moves according to bioplausible visual cues, in particular the optic flow. This visual model successfully reproduces three classical collective behaviors: swarming (no orientational order), schooling (high orientational order), and milling (the group coordinately swirls in a circular pattern). >>️

Diego Castro, Franck Ruffier, Christophe Eloy. Modeling collective behaviors from optic flow and retinal cues. Phys. Rev. Research 6, 023016. Apr 4, 2024. 

https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.6.023016

Also: swarm, flock, behav, particle, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, swarming, flocking, behavior, particle, self-propelled particles

# behav: ADHD may have been a feature of nomadic exploration among hunter-gatherer societies

<< All mobile organisms forage for resources, choosing how and when to search for new opportunities by comparing current returns with the average for the environment. In humans, nomadic lifestyles favouring exploration have been associated with genetic mutations implicated in attention deficit hyperactivity disorder (ADHD), inviting the hypothesis that this condition may impact foraging decisions in the general population. >>️

David L. Barack, Vera U. Ludwig, et al. 

Attention deficits linked with proclivity to explore while foraging. Proc Royal Society B.  doi: 10.1098/ rspb.2022.2584. Feb 21, 2024. 

https://doi.org/10.1098/rspb.2022.2584     

<< Is it a legacy of the hunter-gatherer world? >> Arjun Ramakrishnan

Chen Ly. ADHD may have evolved to help foragers know when to cut their losses. newscientist.com Feb 21,2024.

https://www.newscientist.com/article/2418114-adhd-may-have-evolved-to-help-foragers-know-when-to-cut-their-losses

Also: nomads, bushmen, behav, uncertainty, curiosity, in https://www.inkgmr.net/kwrds.html

Keywords: adhd, nomads, hunter-gatherers, behavior, behaviour

# behav: mechanics of fire ant rafts as an active self-healing membrane

<< The unique ability of fire ants to form a raft to survive flooding rain has enchanted biologists as well as researchers in other disciplines. (..) a three-dimensional aggregation of fire ants exhibits viscoelasticity with respect to external compression and shearing among numerous unusual mechanical properties. >>️

AA << study the ant raft in its natural form, i.e., composing no more than two layers. This allowed to focus on the cracks that are unique to membranes and see how their patterns are influenced by the fact that these ants are mobile and can self-repair the damage to keep their raft from disintegration. >>️

They << show that vertical and horizontal shaking can also prompt fire ants to aggregate.  (..)  the pull force expedites the alignment of fire ants, in analogy to the effect of an electric field on liquid crystal polymers. >>️

<< One major finding is that the raft can exhibit zero Poisson's ratio without resorting to specific geometry structures. This is enabled by the active recruitment of ants from the top layer to the bottom layer to keep the raft from disintegrating. >>️

️

Chung-Hao Chen, Ting-Heng Hsieh, et al. Formation and mechanics of fire ant rafts as an active self-healing membrane. Phys. Rev. E 109, 014607. Jan 9, 2024. 

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.109.014607

David Ehrenstein. Material Properties of Fire-Ant Rafts. Physics 17, s5. Jan 9. 2024. 

https://physics.aps.org/articles/v17/s5

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

zattera (quasi-stochastic poetry) https://inkpi.blogspot.com/2005/04/1864-onda-di-liberazione.html  

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

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

Keywords behavior, behaviour, ant, raft, self-healing

# behav: the self-care hypothesis of the puteketeke bird (great crested grebe, Podiceps cristatus)

<< The Puteketeke bird has been elected as New Zealand's Bird of the Century after John Oliver promoted the bird not just on his show, but around the world. >>

<< It also exhibits some unusual antics, like eating feathers to help it vomit up parasites,  >> AILSA CHANG

️

<< They have a mating dance where they both grab a clump of wet grass and chest bump each other... >> JOHN OLIVER

Kat Lonsdorf, Christopher Intagliata. The Puteketeke bird has been elected as New Zealand's Bird of the Century. npr.org Nov 15, 2023. 

https://www.npr.org/2023/11/15/1213287236/the-puteketeke-bird-has-been-elected-as-new-zealands-bird-of-the-century

L’uccello del secolo della Nuova Zelanda l’ha deciso John Oliver. ilpost.it. Nov 15, 2023. 

https://www.ilpost.it/2023/11/15/john-oliver-uccello-secolo-nuova-zelanda/

the bird: https://youtu.be/98ceB5SPRXI

John Oliver, an interview: https://youtu.be/uVE1hBzHn3s

many thanks to Tammi ( https://www.inkgmr.net/tammi ) for this news. 

Also: Self-perception of health and survival. A 10-year follow-up among Italians aged over sixty. INRCA, Technical Report, Genova, 7 March 1995: 1-19. Minerva Med 1997 Jan-Feb 88:1-2 15-23. [abst] https://pubmed.ncbi.nlm.nih.gov/9093288/

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

Keywords: behaviour, self-care, perceptions

# gst: emergence of self-organizing zigzag patterns among (magnetic) particles suspended in a liquid

<< When molecules or bacteria organize into a long-range pattern, researchers want to understand how the microscopic interactions lead to the macroscopic order. (AA) observed such self-organization in magnetic particles suspended in a liquid and subjected to an oscillating magnetic field. Through experiments and simulations, the team showed that the resulting zigzag pattern is explained by the fluid flow generated around the oscillating particles, not by any details of the particles or the applied field. Similar zigzag patterns have also been seen in charged colloids subjected to oscillating electric fields, so the explanation may cover a range of particle systems. The researchers also believe that understanding and controlling the effect could lead to useful applications in microfluidics devices. >>️

David Ehrenstein. Self-Organized Zigzags from Fluid Flow. Physics 16, 138. Aug 11, 2023.

https://physics.aps.org/articles/v16/138

Gaspard Junot, Marco De Corato, Pietro Tierno. Large Scale Zigzag Pattern Emerging from Circulating Active Shakers. Phys. Rev. Lett. 131, 068301. Aug 11, 2023. 

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.131.068301

Also: particle, self-assembly, chiral, behav, in: https://www.inkgmr.net/kwrds.html  

Keywords: gst, behavior, particle, self-assembly, self-organization, chiral, active shakers, squirmers, alternating chirality

# behav: use of social information in flight (among ‘griffon’ vultures Gyps fulvus and G. rueppellii)

 <<Animals rely on a balance of personal and social information to decide when and where to move next in order to access a desired resource, such as food. The benefits from cueing on conspecifics to reduce uncertainty about resources availability can be rapidly overcome by the risks of within-group competition, often exacerbated toward low-ranked individuals. Being obligate soarers, relying on thermal updrafts to search for carcasses around which competition can be fierce, vultures represent ideal models to investigate the balance between personal and social information during foraging movements. Linking dominance hierarchy, social affinities and meteorological conditions to movement decisions of eight captive vultures, Gyps spp., released for free flights in natural-like soaring conditions,  (AA) found that they relied on social information (i.e. other vultures using/having used the thermals) to find the next thermal updraft, especially in unfavourable flight conditions. Low-ranked individuals were more likely to disregard social cues when deciding where to go next, possibly to minimise the competitive risk of social aggregation. These results exemplify the architecture of decision-making during flight in social birds. It suggests that the environmental context, the context of risk and the social system as a whole calibrate the balance between personal and social information use. >> 

Sassi Yohan, Nouzieres Basile, Scacco Martina, et al. The use of social information in vulture flight decisions. bioRxiv. doi: 10.1101/ 2023.07.26.550671. Jul 28, 2023.

https://www.biorxiv.org/content/10.1101/2023.07.26.550671v1

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

# behav: how a microbiota (Curvibacter sp.) could modulate eating behavior in Hydra.

(AA) << studied the eating behavior of Hydra, a host that has a simple nervous system and a low-complexity microbiota. >>

(They) << demonstrate that different neuronal subpopulations are functioning together to control the eating behavior. The microbiota participates in control of the eating behavior since germ-free or mono-colonized animals have drastic difficulties in mouth opening. This was restored by adding a full complement of the microbiota. >>️

The << findings confirm and expand on the idea that in animals without a central nervous system, a complex behavior is controlled by multiple subpopulations of neurons, forming circuits and modules. (Their)  observations presented here show that this not only requires the coordination of multiple neuronal circuits, but also that signals from the microbial environment play an important role. >>

Christoph Giez, Denis Pinkle, et al.  Microbes as part of ancestral neuronal circuits: Bacterial produced signals affect neurons controlling eating behavior in Hydra. BioRxiv. doi: 10.1101/ 2023.04.28.538719. Apr 29, 2023. 

https://www.biorxiv.org/content/10.1101/2023.04.28.538719v1

Also: How a virus could cause context-dependent manipulation in host social behavior.  Apr 28, 2020.  https://flashontrack.blogspot.com/2020/04/gst-how-virus-could-cause-context.html

Keywords: behav, eating behavior, food, Hydra, microbiota