# 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 

# 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

# 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 

# gst: apropos of the shepherding problem, a collision-free model between sheep and shepherd

<< The shepherding problem refers to guiding a group of agents (called sheep) to a specific destination using an external agent with repulsive forces (called shepherd). Although various movement algorithms for the shepherd have been explored in the literature, there is a scarcity of methodologies for selective guidance, which is a key technology for precise swarm control. >>️

AA << study investigates the problem of guiding a single target sheep within a swarm to a given destination using a shepherd. (AA) first present (their) model of the dynamics of sheep agents and the interaction between sheep and shepherd agents. The model is shown to be well-defined with no collision if the interaction magnitude between sheep and shepherd is reasonably limited. Based on the analysis with Lyapunov stability principles, (AA) design a shepherd control law to guide the target sheep to the origin while avoiding collisions among sheep agents. >>️

Yaosheng Deng, Aiyi Li, Masaki Ogura, Naoki Wakamiya. Collision-Free Shepherding Control of a Single Target within a Swarm. arXiv: 2306.12044v1 [nlin.AO]. Jun 21, 2023.

https://arxiv.org/abs/2306.12044

Also:  behav, swarm, game, sadistic, ctz  in:  https://www.inkgmr.net/kwrds.html

Keywords: gst, behav, swarm, game

# behav: predicting long-term collective behavior with deep learning (among fish species Hemigrammus rhodostomus)

<< Deciphering the social interactions that govern collective behavior in animal societies has greatly benefited from advancements in modern computing. Computational models diverge into two kinds of approaches: analytical models and machine learning models. This work introduces a deep learning model for social interactions in the fish species Hemigrammus rhodostomus, and compares its results to experiments and to the results of a state-of-the-art analytical model. To that end, (AA) propose a systematic methodology to assess the faithfulness of a model, based on the introduction of a set of stringent observables. (They) demonstrate that machine learning models of social interactions can directly compete against their analytical counterparts. Moreover, this work demonstrates the need for consistent validation across different timescales and highlights which design aspects critically enables (AA) deep learning approach to capture both short- and long-term dynamics. (AA) also show that this approach is scalable to other fish species. >>️

Vaios Papaspyros, Ramon Escobedo, et al. Predicting long-term collective animal behavior with deep learning. bioRxiv. doi: 10.1101/ 2023.02.15.528318. Feb 15, 2023.

https://www.biorxiv.org/content/10.1101/2023.02.15.528318v1

Also

keywords 'behav' in FonT

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

keyword 'ai' in FonT

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

keyword 'ia' | 'ai' in Notes 

(quasi-stochastic poetry)

https://inkpi.blogspot.com/search?q=ia

https://inkpi.blogspot.com/search?q=ai

Keywords: ai, gst, behav, behavior, cognition, machine learning, deep learning, social interactions

# gst: behavior of microswimmers in a vortex with translational and rotational noise

AA << propose a theoretical model to investigate the dynamics of elongated microswimmers in elementary vortices, namely active particles in two- and three-dimensional rotlets. A deterministic model first reveals the existence of bounded orbits near the centre of the vortex and unbounded orbits elsewhere. (AA) further discover a conserved quantity of motion that allows (..) to map the phase space according to the type of the orbit (bounded vs unbounded). (They) next introduce translational and rotational noise into the system. Using a Fokker--Planck formalism, (AA) quantify the quality of trapping near the centre of the vortex by examining the probability of escape and the mean time of escape from the region of deterministically bounded orbits. (AA) finally show how to use these findings to formulate a prediction for the radius of the depletion zone, which compares favourably with the experiments of Sokolov and Aranson (2016). >>

Ivan Tanasijevic, Eric Lauga. Microswimmers in vortices: Dynamics and trapping. arXiv: 2211.05866v1 [physics.bio-ph].  Nov 10, 2022. 

https://arxiv.org/abs/2211.05866

Also

'microswimmers' in FonT 

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

Keywords: gst, behav, translation,  rotation, trapping, noise, swimmer, swimming,  microswimmers, fluid dynamics, vortex, vortices, vortexes, vorticity

# gst: apropos of swarms: local couplings, chirality, lattices of vortices, beating clusters, interacting phase waves among swarmalators.

AA << study the emergent behaviors of a population of swarming coupled oscillators, dubbed 'swarmalators'. (..)  Here (they) expand this work by adding more realistic features: local coupling, non-identical natural frequencies, and chirality. This more realistic model generates a variety of new behaviors including lattices of vortices, beating clusters, and interacting phase waves. Similar behaviors are found across natural and artificial micro-scale collective systems, including social slime mold, spermatozoa vortex arrays, and Quincke rollers. >>

Steven Ceron, Kevin O'Keeffe, Kirstin Petersen. Diverse Behaviors in Non-Uniform Chiral and Non-Chiral Swarmalators. arXiv: 2211.06439v1 [nlin.AO]. Nov 11, 2022.

https://arxiv.org/abs/2211.06439

Also

keyword 'swarm' in FonT

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

keyword 'chiral' in FonT

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

keyword 'vortex' in FonT

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

keyword 'vortice' in Notes

(quasi-stochastic poetry)

https://inkpi.blogspot.com/search?q=vortice

Keywords: gst, behav, behavior, behaviour, swarm, swarmalators, chirality, chiral swarmalators, non-chiral swarmalators, vortex, vortex array, vortices, vorticity, slime mold.

# gst: apropos of transitions, the transition from sticking to slipping.

<< From hydrogels and plastics to liquid crystals, soft solids cover a wide array of synthetic and biological materials that play key enabling roles in advanced technologies >>️

<< Attempts to study the interactions between soft solids and liquids have largely focused on the wetting of soft solids and its resulting deformation at equilibrium or in a quasi-static state. Here, (AA) consider the frequently encountered case of unsteady wetting of a liquid on a soft solid and show that transient deformation of the solid is necessary to understand unsteady wetting behaviours. >>️

AA << find that the initial spreading of the liquid occurs uninterrupted in the absence of solid deformation. This is followed by intermittent spreading, in which transient deformation of the solid at the three-phase contact line (CL) causes the CL motion to alternate alternation between CL sticking and slipping. (They) identify the spreading rate of liquids and the viscoelastic reacting rate of soft solids as the two competing factors in dictating intermittent spreading. (They)  formulate and validate experimentally the conditions required for the contact line to transition from sticking to slipping. By considering the growing deformation of soft solids as dynamic surface heterogeneities, (AA) proposed conditions for stick-slip transition in unsteady wetting on soft solids broaden the classical theory on wetting hysteresis on rigid solids. >>️

Surjyasish Mitra, Quoc Vo, Marcus Lin, Tuan Tran. Unsteady wetting of soft solids. arXiv:2211.07043v1 [cond-mat.soft]. Nov 13, 2022.

https://arxiv.org/abs/2211.07043

Also

keyword 'drop' | 'droplet' | 'droploids' in FonT

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

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

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

keyword 'goccia' in Notes 

(quasi-stochastic poetry) 

https://inkpi.blogspot.com/search?q=goccia

Keywords: gst, behav, behaviour, transition, soft solids, drop, droplet, sticking, slipping.

# behav: cry / not cry, babe ... POMC neurons modulate the crying behavior of pups (among mice)

<< Infants cry when separated from their mothers. Here, (AA) show that POMC (pro-opiomelanocortin) neurons in the arcuate nucleus of the hypothalamus—via ß-endorphin production and signaling—modulate the crying behavior of mouse pups. The effect of POMC neurons on vocal behavior depends on the expression of µ-opioid receptors, the main receptor for ß-endorphin. Thus, POMC neurons in the hypothalamus modulate infant cry through opioid signaling. >>️

Gabriela M. Bosque Ortiz, Marcelo O. Dietrich. POMC neurons modulate infant vocalizations through opioid signaling. bioRxiv 2022.08.15.504046. 

doi: 10.1101/ 2022.08.15.504046. Aug 15, 2022. 

https://www.biorxiv.org/content/10.1101/2022.08.15.504046v1

Also

keywords 'behav' in FonT

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

keyword 'pnei' in FonT

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

keyword 'pnei' in Notes 

(quasi-stochastic poetry)

https://inkpi.blogspot.com/search?q=pnei

Keywords: behav, brain, pnei, opioid signaling

# behav: cognitive maps to get out of trouble, a jumping behaviour could be a goal-directed behaviour (in guppies, Poecilia reticulata).

<< Spatial cognitive abilities allow individuals to remember the location of food patches, predator hide-outs, or shelters. Animals typically incorporate learnt spatial information or use external environmental cues to navigate their surroundings. A spectacular example of how some fishes move is through aerial jumping. >>️

<< what information such re-orientation behaviour during jumping is based on remains enigmatic. Here (AA) combine a lab and field experiment to test if guppies (Poecilia reticulata) incorporate learnt spatial information and external environmental cues (visual and auditory) to determine where to jump. >>

AA << show that in unfamiliar entrapments guppies direct their jumps by combining visual and auditory cues, while in familiar entrapments they use a cognitive map. (..) jumping behaviour is a goal-directed behaviour, guided by different sources of information and involving important spatial cognitive skills. >>️️

Hannah de Waele, Catarina Vila Pouca, et al. Jumping out of trouble: Evidence for a cognitive map in guppies (Poecilia reticulata).  bioRxiv. doi: 10.1101/ 2022.03.30.486400. Mar 30, 2022.

https://www.biorxiv.org/content/10.1101/2022.03.30.486400v1

Also

Voli a casaccio. Notes (quasi-stochastic poetry). Oct 01, 2006. 

https://inkpi.blogspot.com/2006/10/2066-voli-casaccio.html

the flexible mental maps of flies. FonT. Nov 21, 2019. 

https://flashontrack.blogspot.com/2019/11/brain-flexible-mental-maps-of-flies.html

Keyword: behav, cognition, jumping behaviour, aerial jumping

# life: Chimps distribute their time to groom other individuals in the same manner as humans structure their relationships.

AA << show that the time chimpanzees devote to grooming other individuals is well described by the same model used for human relationships, supporting the existence of similar social signatures for both humans and chimpanzees. Furthermore, the relationship structure depends on group size as predicted by the model, the proportion of high intensity connections being larger for smaller groups. >>

Diego Escribano, Victoria Doldan-Martelli, et al. Chimpanzees organize their social relationships like humans. bioRxiv. doi: 10.1101/ 2022.03.16.484664. March 17, 2022. 

https://www.biorxiv.org/content/10.1101/2022.03.16.484664v1

Also

keywords 'chimp' | 'chimps' in FonT

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

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

keyword 'chimps' | 'sileno' in Notes (quasi-stochastic poetry)

https://inkpi.blogspot.com/search?q=chimps

https://inkpi.blogspot.com/search?q=sileno

keywords 'behav' in FonT

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

keywords: life, chimps, behav, behavior, behaviour, social relationships

# behav: learning walks related to home burrow navigation (among desert grassland scorpions Paruroctonus utahensis)

<< The Navigation by Chemotextural Familiarity Hypothesis (NCFH) suggests that scorpions use their midventral pectines to gather chemical and textural information near their burrows and use this information as they subsequently return home. For NCFH to be viable, animals must somehow acquire home-directed “tastes” of the substrate, such as through path integration (PI) and/or learning walks. >>️

AA << found that once animals established their home burrows, they immediately made one to several short, looping excursions away from and back to their burrows before walking greater distances. We also observed similar excursions when animals made burrows in level sand in the middle of the arena (i.e., no mound provided). These putative learning walks, together with recently reported PI in scorpions, may provide the crucial home-directed information requisite for NCFH. >>️

Douglas D. Gaffin, Maria G. Munoz, Marielle Hoefnagels. Evidence of learning walks related to scorpion home burrow navigation. bioRxiv 2021.12.28.474378; Dec 30, 2021. 

https://www.biorxiv.org/content/10.1101/2021.12.28.474378v1

Also

keyword 'walk' | 'walking' in FonT

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

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

keyword 'passo lieve' | 'walk' | 'walking' in Notes (quasi-stochastic poetry)

https://inkpi.blogspot.com/search?q=passo+lieve

https://inkpi.blogspot.com/search?q=walk

https://inkpi.blogspot.com/search?q=walking

Keywords: behav, walk, walking, learning walk, NCFH

# behav: unfrequent events under radical uncertainty; rats tend to avoid black swan situations.

AA << present a novel experimental design that aims at measuring the extent to which animal subjects are sensitive to rare and extreme events and, in addition, how rats respond to those very unfrequent events under radical uncertainty. (..) the novelty of (AA) design is that it provides two direct measures that help interpreting (..) behavioral data: Total Sensitivity to Rare and Extreme Events, and One-sided Sensitivity to Rare and Extreme Events with Black-Swan Avoidance/Jackpot-Seeking behaviors as limiting cases. >>️

<< First, most rats (..) can be grouped into a moderate to high Total Sensitivity group. This means that most rats diversify their choices across options in such a way that they more often rely on convex ones than on concave ones overall. Therefore, they tend to seek extreme gains/Jackpots and to avoid extreme losses/ Black Swans. In addition, most rats (..) tend to exhibit Black Swan Avoidance, which indicates that, given Total Sensitivity, they tend to try more often to avoid Black Swans than to seek Jackpots. (AA) interpret such a behavior as significant aversion towards uncertainty about rare and extreme losses.  >>️

<< all rats diversify their choices across a set of options, which is reminiscent of observed behaviors such as, for example, bet-hedging in animals and financial portfolio strategies used by humans >>

️

<< results from similar experiments among different species might be of interest for the analysis of neurobiological substrates involved in decision-making and its evolutionary traits in the context of rare and extreme events. >>️

Mickael Degoulet, Louis-Matis Willem, et al. Decision-Making in Rats is Sensitive to Rare and Extreme Events: the Black Swan Avoidance. bioRxiv 10.1101/2021.11.01.466806v1. Nov 04, 2021. 

https://www.biorxiv.org/content/10.1101/2021.11.01.466806v1

 Keywords: behav, game, decision-making, bet-hedging, trading, uncertainty, gain, loss, black swan 

# gst: reshaping Kuramoto model, when a collective dynamics becomes chaotic, with a surprisingly weak coupling.

<< The emergence of collective synchrony from an incoherent state is a phenomenon essentially described by the Kuramoto model (..) Collective synchronization is a phenomenon in which an ensemble of heterogeneous, self-sustained oscillatory units (commonly known as oscillators) spontaneously entrain their rhythms. This is a pervasive phenomenon observed in natural systems and man-made devices, covering a wide range of spatio-temporal scales, from cell aggregates to swarms of fireflies >>

<< However, this is only partly true, (..) Kuramoto’s perturbative phase-reduction approach is valid for weak coupling. Specifically, oscillator heterogeneity and interactions appear at zeroth and linear orders in the coupling constant, respectively. >> 

AA << have introduced the ‘enlarged Kuramoto model’; a population of phase oscillators in which three-body interactions enter in a perturbative way. Remarkably, this makes a world of difference, drastically reshaping the traditional Kuramoto scenario. The ‘enlarged Kuramoto model’ exhibits a variety of unsteady states, including collective chaos and hyperchaos. >>

Ivan Leon, Diego Pazo. Enlarged Kuramoto Model: Secondary Instability and Transition to Collective Chaos. arXiv: 2112.00176v1 [nlin.AO]. Nov 30, 2021.

https://arxiv.org/abs/2112.00176

Also

More on the three-body problem (695 families of collisionless orbits). FonT. Oct 16, 2017. 

https://flashontrack.blogspot.com/2017/10/gst-more-on-three-body-problem-695.html

Keywords: gst, behav, instability, Kuramoto model, three-body interactions, chaos, collective chaos, hyperchaos.