# gst: rearrangements of a jammed 2-D emulsion (during slow compression).

<< As amorphous materials get jammed, both geometric and dynamic heterogeneity are observed. (AA)  investigate the correlation between the local geometric heterogeneity and local rearrangements in a slowly compressed bidisperse quasi-two-dimensional emulsion system. The compression is driven by evaporation of the continuous phase. >>

<< droplets in heterogeneous local regions are more likely to have local rearrangements. These rearrangements are generally T1 events where two droplets converge toward a void, and two droplets move away from the void to make room for the converging droplets. Thus, the presence of the voids tends to orient the T1 events. >>️

<< The presence of a correlation between the structural quantities and the rearrangement dynamics remains qualitatively unchanged over the entire range of packing fractions observed. >>️

Xin Du, Eric R. Weeks. Rearrangements during slow compression of a jammed  two-dimensional emulsion. Phys. Rev. E 109, 034605. Mar 20,  2024.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.109.034605

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

Keywords: drops, droplets, droploids 

# brain: apropos of wars ... VR plus tDCS to reduce symptoms of posttraumatic stress disorder (PTSD) (in military veterans).

<< Key Points. Question. Can therapeutic exposure using virtual reality (VR) be augmented with simultaneously applied transcranial direct current stimulation (tDCS) to reduce symptoms of posttraumatic stress disorder (PTSD)? >>

<< Meaning. These findings suggest that the use of combined VR exposure plus tDCS could be a promising treatment for warzone-related PTSD. >>️️

Mascha van’t Wout-Frank, Amanda R. Arulpragasam, et al. Virtual Reality and Transcranial Direct Current Stimulation for Posttraumatic Stress Disorder. A Randomized Clinical Trial. JAMA Psychiatry. doi: 10.1001/jamapsychiatry.2023.5661. Mar 6, 2024.

https://jamanetwork.com/journals/jamapsychiatry/fullarticle/2815835

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

Keywords: life, war, brain, VR, tDCS, PTSD, veterans

# gst: near the Hopf boundary, Intermittency and chimera states.

AA << study collective dynamics of networks of mutually coupled identical Lorenz oscillators near a subcritical Hopf bifurcation. Such systems exhibit induced multistable behavior with interesting spatiotemporal dynamics including synchronization, desynchronization, and chimera states. >>️

<< For analysis, (AA) first consider a ring topology with nearest-neighbor coupling and find that the system may exhibit intermittent behavior due to the complex basin structures and dynamical frustration, where temporal dynamics of the oscillators in the ensemble switches between different attractors. Consequently, different oscillators may show a dynamics that is intermittently synchronized (or desynchronized), giving rise to intermittent chimera states. The behavior of the intermittent laminar phases is characterized by the characteristic time spent in the synchronization manifold, which decays as a power law. >>

<< Such intermittent dynamics is quite general and is also observed in an ensemble of a large number of oscillators arranged in variety of network topologies including nonlocal, scale-free, random, and small-world networks. >>️

Anjuman Ara Khatun, Yusra Ahmed Muthanna, et al. Collective dynamics of coupled Lorenz oscillators near the Hopf boundary: Intermittency and chimera states. Phys. Rev. E 109, 034208. March 15, 2024.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.109.034208

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

Keywords: gst, transition, intermittency, chaos, chimera, network

# gst: apropos of random walks, intermittent random walks under stochastic resetting

AA << analyze a one-dimensional intermittent random walk on an unbounded domain in the presence of stochastic resetting. In this process, the walker alternates between local intensive search, diffusion, and rapid ballistic relocations in which it does not react to the target. >>

AA << demonstrate that Poissonian resetting leads to the existence of a non-equilibrium steady state. (They) calculate the distribution of the first arrival time to a target along with its mean and show the existence of an optimal reset rate. In particular, (..) the initial condition of the walker, i.e., either starting diffusely or relocating, can significantly affect the long-time properties of the search process. >>

<< the presence of distinct parameter regimes for the global optimization of the mean first arrival time when ballistic and diffusive movements are in direct competition. >>️

Rosa Flaquer-Galmes, Daniel Campos,  Vicenc Mendez. Intermittent random walks under stochastic resetting. Phys. Rev. E 109, 034103. March 4, 2024. 

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.109.034103  

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

Keywords: gst, walk, intermittent random walk, stochasticity, stochastic resetting

# gst: multi-component droplets may exhibit self-lubricating effects

<< Over the past decade, there has been a growing interest in the study of multicomponent drops. These drops exhibit unique phenomena, as the interplay between hydrodynamics and the evolving physicochemical properties of the mixture gives rise to distinct and often unregulated behaviors. >>

<< Of particular interest is the complex dynamic behavior of the drop contact line, which can display self-lubrication effect. The presence of a slipping contact line in self-lubricating multicomponent drops can suppress the coffee-stain effect, conferring valuable technological applications. >>

Huanshu Tan, Detlef Lohse, Xuehua Zhang. Self-Lubricating Drops. arXiv: 2403.01207v1 [physics.flu-dyn]. Mar 2, 2024

https://arxiv.org/abs/2403.01207

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

Keywords: drop, droplet, droploid, multicomponent drops, drop contact line, self-lubrication

# brain: apropos of mandering minds, the 'default mode' network.

<< When your mind is wandering, your brain’s “default mode” network is active. Its discovery 20 years ago inspired a raft of research into networks of brain regions and how they interact with each other. >>

<< The default mode was one of the first brain networks characterized by science. It consists of a handful of brain regions, including a few at the front of the brain, like the dorsal and ventral medial prefrontal cortices, and others scattered throughout the organ, like the posterior cingulate cortex, the precuneus and the angular gyrus. These regions are associated with memory, experience replay, prediction, action consideration, reward/ punishment and information integration. >> ️

<< The default mode is clearly up to something complicated; it’s involved in many different processes that can’t be neatly described. >>

<< “It’s kind of silly to think that we’re ever going to be like, ‘This one brain region or one brain network does one thing,’” (..). “I don’t think that’s how it works.” (..) “Network interactions are more elucidating to study in some ways than just a network in isolation because they do work together and then come apart and then change what they’re doing over time”. >> Lucina Uddin.️

Lucina Uddin << is particularly interested in how the default mode network interacts with the ️salience network, which seems to help us identify the most relevant piece of information at any given time. Her work suggests that the salience network detects when something is important to pay attention to and then acts as an off switch for the default mode network. >>

Vinod Menon << has developed what he calls️ ️the triple network theory. It posits that abnormal interactions between the default mode network, the salience network and a third one called the frontoparietal network could contribute to mental health disorders. >>️

Nora Bradford. What Your Brain Is Doing When You’re Not Doing Anything.  quantamagazine.org. Feb 5, 2024. 

https://www.quantamagazine.org/what-your-brain-is-doing-when-youre-not-doing-anything-20240205/

FonT: the cat when it is in a contemplative state ... Who knows in what forms and with what results an artificial intelligence (AI) will be able to structure itself in networks of this type.

Also: brain, brain default mode network, in  https://pubmed.ncbi.nlm.nih.gov/?term=brain+default+mode+network

Also: brain, salience network, in https://pubmed.ncbi.nlm.nih.gov/?term=brain+salience+network

Also: brain, triple network theory, in https://pubmed.ncbi.nlm.nih.gov/?term=brain+triple+network+theory

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

Keywords: brain, mind, default mode network, salience network, triple network theory, AI

# gst: self-trapped nonlinear waves with multiple phase singularities.

AA << investigate the existence of self-trapped nonlinear waves with multiple phase singularities. >>️

They << focus on configurations with an antivortex surrounded by a triangular arrangement of vortices within a hosting soliton. (AA) find stationary patterns that can be interpreted as stable self-trapped vortex crystals, constituting the first example of a configuration of this sort with space-independent potentials. Their stability is linked to their norm, transitioning from unstable to stable as their size increases, with an intermediate region where the structure is marginally unstable, undergoing a remarkable and puzzling self-reconstruction during its evolution. >>️

Angel Paredes and Humberto Michinel. Self-trapping of vortex crystals via competing nonlinearities.  Phys. Rev. E 109, 024216. Feb 22, 2024. 

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.109.024216

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

Keywords: gst, waves, soliton, self-trapping, vortex