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giovedì 23 marzo 2023

# gst: apropos of weakly coupled oscillators, a new approach to depict about their spontaneous stochastic activities

<<  Many systems in physics, chemistry and biology exhibit oscillations with a pronounced random component. Such stochastic oscillations can emerge via different mechanisms, for example linear dynamics of a stable focus with fluctuations, limit-cycle systems perturbed by noise, or excitable systems in which random inputs lead to a train of pulses. Despite their diverse origins, the phenomenology of random oscillations can be strikingly similar. >>


<< Here (AA) introduce a nonlinear transformation of stochastic oscillators to a new complex-valued function Q∗1(x) that greatly simplifies and unifies the mathematical description of the oscillator's spontaneous activity, its response to an external time-dependent perturbation, and the correlation statistics of different oscillators that are weakly coupled. >>

AA << approach makes qualitatively different stochastic oscillators comparable, provides simple characteristics for the coherence of the random oscillation, and gives a framework for the description of weakly coupled oscillators. >>️

Alberto Pérez-Cervera, Boris Gutkin, et al. A Universal Description of Stochastic Oscillators. arXiv: 2303.03198v1 [nlin.AO]. Feb 27, 2023. 

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'oscillations' in FonT

Keywords: gst, oscillations, random oscillations, weakly coupled oscillators



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martedì 21 marzo 2023

# behav: even the first asynchronous decisions might tend to be correct and exhibit information cascades.


<< It is usually assumed that information cascades are most likely to occur when an early but incorrect opinion spreads through the group. Here (AA) analyse models of confidence-sharing in groups and reveal the opposite result: simple but plausible models of naïve Bayesian decision-making exhibit information cascades when group decisions are synchronous; however, when group decisions are asynchronous, the early decisions reached by Bayesian decision makers tend to be correct, and dominate the group consensus dynamics. Thus early decisions actually rescue the group from making errors, rather than contribute to it. (AA) explore the likely realism of our assumed decision-making rule with reference to the evolution of mechanisms for aggregating social information, and known psychological and neuroscientific mechanisms. >>️

Andreagiovanni Reina, Thomas Bose, et al.  Asynchrony rescues statistically-optimal group decisions from information cascades through emergent leaders.  bioRxiv. doi: 10.1101/ 2022.04.05.487127. Feb16, 2023.

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'asynchronous' in FonT
'game' in FonT
'behav' in FonT

Keywords: behavior, behaviour, game, decision-making, synchronous- asynchronous group decisions, social interactions, information cascade, life, jazz


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lunedì 20 marzo 2023

# 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.

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keywords 'behav' in FonT

keyword 'ai' in FonT

keyword 'ia' | 'ai' in Notes 
(quasi-stochastic poetry)


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







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martedì 14 marzo 2023

# gst: porous substrates and foams on the structure of turbulent boundary layers over them.


<< Turbulent flow over and past porous surfaces is encountered in many engineering problems, ranging from flow over forest canopies (..) to flows over and past river beds (..). This makes the understanding or the flow behaviour over porous surfaces crucial. >>
️
<< The present study shows that transition from thick to thin substrate flow behavior depends not only on thickness-to-pore ratio (..) but also on substrate density relative to viscous scales of the flow. >>️

Prateek Jaiswal, Bharathram Ganapathisubramani. Effects of porous substrates on the structure of turbulent boundary layers. arXiv: 2301.04102v1 [physics.flu-dyn]. Jan 10, 2023.

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keyword 'turbulence' in FonT

keyword 'turbolento' | 'turbolenza' in Notes (quasi-stochastic poetry)


Keywords: gst, turbulence, turbulent layers, porosity, porous substrates, foam


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mercoledì 8 marzo 2023

# life: apropos of 1or2achoos (from Wuhan), here is a triptych on the subject.


Apropos of 1or2achoos from Wuhan, here is a triptych on the subject. 

( by Rhiannon Williams. The White House is split over covid’s origins. MIT - The Download. Feb 28, 2023. 


(1)
<< The White House said there is no consensus within the Biden administration over the origins of the Covid-19 virus, a day after the disclosure of an Energy Department assessment that the pandemic most likely originated with a leak from a Chinese lab. >>

Josh Chin, Lindsay Wise, Annie Linskey. White House Says No Consensus on Covid Origin. Comments follow Energy Department assessment that pandemic likely started with leak from Chinese lab. WSJ. Feb. 27, 2023. 

(2)
<< The U.S. Energy Department has concluded that the Covid pandemic most likely arose from a laboratory leak, according to a classified intelligence report recently provided to the White House and key members of Congress. The shift by the Energy Department, which previously was undecided on how the virus emerged, is noted in an update to a 2021 document by Director of National Intelligence Avril Haines’s office. >>

Michael R. Gordon, Warren P. Strobel. Lab Leak Most Likely Origin of Covid-19 Pandemic, Energy Department Now Says. U.S. agency’s revised assessment is based on new intelligence. WSJ. Feb. 26, 2023.

(3)
<< Shi Zhengli has spent years at the Wuhan Institute of Virology researching coronaviruses that live in bats. Her work has come under fire as the world tries to understand where covid-19 came from. >>

Jane Qiu. Meet the scientist at the center of the covid lab leak controversy.  MIT Tech Rev. Feb 9, 2022. 

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<< Qui l'approccio semplice, diretto, efficace che ho usato per la prevenzione ed eventuale gestione personale dell'entità coronavirus /  SARS-COV-2 (SARS: Severe Acute Respiratory Syndrome ) >>

(Here is the simple, direct, effective approach that I used for the prevention and possible personal management of the coronavirus entity)

# life: aproposito di '1or2achoos' (da Wuhan (?)) ... FonT. Jul 13, 2022. 

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keyword 'virus' in FonT

keyword 'virus' in Notes 
(quasi-stochastic poetry)

Keywords:  virus, flu, coronavirus, 2019-ncov, 2019ncov, SARS-CoV-2, sarscov2, covid-19, covid19, 1or2achoos, mask


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giovedì 2 marzo 2023

# gst: when science meets poetry, an image of three-dimensional stepped cracks (bistability, and their transition to simple cracks)


<< Slow cracks may be simple, with no internal structure. The leading edge of a simple crack, the crack front, forms a single fracture plane in its wake. Slow cracks may also develop segmented crack fronts, each segment propagating along a separate fracture plane. These planes merge at locations that form steps along fracture surfaces. Steps are not stationary, but instead propagate within a crack front. Real-time measurements of crack front structure and energy flux reveal that step dynamics significantly increase energy dissipation and drastically alter crack dynamics. Simple and stepped cracks are each stable. By extending the use of energy balance to include 3D crack front structure, (AA) find that, while energy balance is obeyed, it is insufficient to select the energetically favorable crack growth mode. Transitions from stepped cracks to simple cracks occur only when their in-plane front lengths become equal and a perturbation momentarily changes step topology. Such 3D crack dynamics challenge our traditional understanding of fracture. >>

Meng Wang, Mokhtar Adda-Bedia, Jay Fineberg. Dynamics of three-dimensional stepped cracks, bistability, and their transition to simple cracks. Phys. Rev. Research 5, L012001. Jan 9, 2023. 

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keyword 'crack' in FonT

keyword 'rottura' | 'crepa' | 'frattura' | 'rugosa' in Notes
(quasi-stochastic poetry)




keywords 'meets poetry' in FonT

Keywords:  gst, transitions, dynamical phase transitions, crack, cracking,   fracture, roughness





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martedì 28 febbraio 2023

# gst: flocking transitions of unfriendly species.

AA consider << two kinds of self-propelled particles, A and B, that tend to align with particles from the same species and to antialign with the other. The model shows a flocking transition (..) it has a liquid-gas phase transition and displays micro-phase-separation in the coexistence region where multiple dense liquid bands propagate in a gaseous background. >>


<< The interesting features (..) are the existence of two kinds of bands, one composed of mainly A particles and one mainly of B particles, the appearance of two dynamical states in the coexistence region: the PF (parallel flocking) state in which all bands of the two species propagate in the same direction, and the APF (antiparallel flocking) state in which the bands of species A and species B move in opposite directions. When PF and APF states exist in the low-density part of the coexistence region they perform stochastic transitions from one to the other. The system size dependence of the transition frequency and dwell times show a pronounced crossover that is determined by the ratio of the band width and the longitudinal system size. >>

AA << work paves the way for studying multispecies flocking models with heterogeneous alignment interactions. >>

Swarnajit Chatterjee, Matthieu Mangeat, et al. Flocking of two unfriendly species: The two-species Vicsek model. Phys. Rev. E 107, 024607. Feb 14, 2023

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keyword 'swimmers' in FonT

Keywords: gst, flocking, particles, self-propelled particles, swimmers,  microswimmers


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