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martedì 21 gennaio 2025

# life: dear Mr. Donald, fuzzy evidence should be sharper, sooner or later, by Nature

       Nature | 637 | 16 Jan 2025 | 517

<< Mr President-elect, science is a self-correcting process in which bad actors and wrong ideas sooner or later get rooted out and fuzzy evidence becomes sharper. That is the joy and the beauty of the method that has made the modern world what it is. >>️

Editorial. Dear Donald Trump: A letter from Nature on how to make science thrive. Nature 637, 517. Jan 15, 2025.

Also: Mr. Donald, forms of power, virus, sars* covid* (aka 1or2achoos), dance, are you ready for all this, in https://www.inkgmr.net/kwrds.html 

Also: A new exception within the FDA Cures Act Informed Consent, the intriguing concept of 'Minimal Risk Clinical Investigations'. FonT. Feb 1, 2024. 

Also: 'acad' in FonT https://flashontrack.blogspot.com/search?q=acad    in Notes (quasi-stochastic poetry) https://inkpi.blogspot.com/search?q=acad 

Keywords: life, Mr. Donald, forms of power, virus, sars, covid, 1or2achoos, acad, dance, are you ready


sabato 18 gennaio 2025

# gst: traveling strings of active dipolar colloids.

AA << study an intriguing new type of self-assembled active colloidal polymer system in 3D. It is obtained from a suspension of Janus particles in an electric field that induces parallel dipoles in the particles as well as self-propulsion in the plane perpendicular to the field. >>

<< At low volume fractions, in experiment, the particles self-assemble into 3D columns that are self-propelled in 2D. Explicit numerical simulations combining dipolar interactions and active self-propulsion find an activity dependent transition to a string phase by increasing dipole strength. >>

AA << classify the collective dynamics of strings as a function of rotational and translational diffusion. (..) (They) also discover long range correlations of the fluctuations along the string contour that grow with the active persistence time, a purely active effect that disappears in the thermal limit. >>

Xichen Chao, Katherine Skipper, et al. Traveling Strings of Active Dipolar Colloids. Phys. Rev. Lett. 134, 018302. Jan 6, 2025. 

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

Keywords: gst, particle, colloids, self-assembly, Janus, polymers, strings, transition


venerdì 17 gennaio 2025

# gst: diffusion of active particles driven by odd interactions.

<< Odd systems do not conserve energy, violate time-reversal symmetry, and remain far from equilibrium. How odd interactions between particles affect their diffusion remains unknown. >>

<< To investigate this issue, (AA) studied the diffusion and glass transition of a two-dimensional Kob-Andersen mixture, where Brownian particles interact via the Lennard-Jones potential and nonconservative odd forces. (Their) findings indicate a significant influence of odd interactions on the system's diffusion dynamics. Odd interactions always promote diffusion. These interactions lead to a nonmonotonic relationship between the effective diffusion coefficient and particle number density. >>

<< Specifically, in systems with low oddness, the diffusion coefficient decreases steadily with increasing particle number density. Conversely, in systems with moderate oddness, an optimal particle number density exists that maximizes the diffusion coefficient. For systems with high oddness, (AA) observe two distinct peaks in the diffusion coefficient-particle number density relationship. >>

<< Furthermore, (AA) investigation into the glass transition under dense conditions reveals that adjusting the oddness at low temperatures can induce a transition from a glassy state to a liquid state. >>

Rui-xue Guo, Jia-jian Li, Bao-quan Ai.
Diffusion of active particles driven by odd interactions. Phys. Rev. E 111, 014105. Jan 3, 2025.


Keywords: gst, particles, diffusion, 
active brownian particles, oddness, odd interactions


giovedì 16 gennaio 2025

# gst: chaotic dynamics creates and destroys branched flow.

<< The phenomenon of branched flow, visualized as a chaotic arborescent pattern of propagating particles, waves, or rays, has been identified in disparate physical systems ranging from electrons to tsunamis, with periodic systems only recently being added to this list. >>

Here, AA << explore the laws governing the evolution of the branches in periodic potentials. On one hand, (They) observe that branch formation follows a similar pattern in all nonintegrable potentials, no matter whether the potentials are periodic or completely irregular. Chaotic dynamics ultimately drives the birth of the branches. >>

<< On the other hand, (AA) results reveal that for periodic potentials the decay of the branches exhibits new characteristics due to the presence of infinitely stable branches known as superwires. Again, the interplay between branched flow and superwires is deeply connected to Hamiltonian chaos. >>

Alexandre Wagemakers, Aleksi Hartikainen, et al. Chaotic dynamics creates and destroys branched flow. Phys. Rev. E 111, 014214. Jan 7, 2025.
arXiv: 2406.12922v2 [nlin.PS]. 

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

Keywords: gst, chaos, waves, branched flows, superwires, transitions


mercoledì 15 gennaio 2025

# gst: acceleration of enzymatic reactions due to nearby inactive binding sites.

<< Many biological molecular motors and machines are driven by chemical reactions that occur in specific catalytic sites. (AA) study whether the arrival of molecules to such an active site can be accelerated by the presence of a nearby inactive site.  >>️

AA << identify two parameter regimes in which the reaction is accelerated. >>️

<< In the first regime, the inactive site stores a molecule in order to release it following a reaction, when the neighboring catalytic site is empty. >>

<< In the second regime, the inactive site releases a molecule when the catalytic site is full, in order to impede the molecules from leaving the active site before they react. For the storage mechanism, which is more likely to be biologically relevant, the acceleration can reach up to 15%, depending on parameters. >>️

Hila Katznelson, Saar Rahav. Acceleration of enzymatic reactions due to nearby inactive binding sites. arXiv: 2501.01662v1 [cond-mat.stat-mech]. Jan 3, 2025.
Phys. Rev. Research 6, 043330. Dec 30, 2024. 

Keywords: gst, enzymes, enzymatic catalysis, catalytic sites, inactivity, inactive binding sites


martedì 14 gennaio 2025

# 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.

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

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


sabato 11 gennaio 2025

# gst: trade-off between coherence and dissipation for excitable phase oscillators.

<< Thermodynamic uncertainty relation (TUR) bounds coherence in stochastic oscillatory systems. In this paper, (AA) show that both dynamical and thermodynamic bounds play important roles for the excitable oscillators, e.g. neurons. >>

<< Excitable systems such as neurons have distinctive coherence features compared with other oscillators having no excitability. >>️

AA << combined the well-established results, i.e. the fluctuation of the ISI (inter-spike-interval) limited by 1/3 and the coherence resonance phenomenon, together with the TUR developed in recent years to investigate the coherence in the excitable phase oscillators. (AA) find quite different trade-off relation in the subthreshold (excitable) region and superthreshold (oscillatory) region, separated by the SNIC (saddle-node on an invariant circle) bound but meanwhile lower bounded by the TUR. Furthermore, (They) found that there is an optimal entropy production corresponding to the maximum coherence, which could serve as an alternative interpretation of the coherence resonance. It implies that more entropy production does not necessarily result in higher accuracy of currents. >>️

Chunming Zheng. Trade-off between coherence and dissipation for excitable phase oscillators. arXiv: 2412.16603v1 [cond-mat.stat-mech]. Dec 21, 2024.

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

Keywords: gst, brain, neurons, entropy, oscillators, excitable phase oscillators, coherence, dissipation, uncertainty