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giovedì 22 luglio 2021

# life: transitions in the edges; to stimulate a shift in thinking, target small groups of people in the "outer edge" or fringe of a network.

<< social influencers are unlikely to change a person's behavior by example. To stimulate a shift in people's thinking, target small groups of people in the outer edge or fringe of a network. (..) as prominent and revered as social influencers seem to be, in fact, they are unlikely to change a person's behavior by example -- and might actually be detrimental to the cause. >>

<< When social influencers present ideas that are dissonant with their followers' worldviews (..) they can unintentionally antagonize the people they are seeking to persuade because people typically only follow influencers whose ideas confirm their beliefs about the world,"  >> Damon Centola. ️

<< To stimulate a shift in thinking, target small groups of people in the "outer edge" or fringe of a network. >>
Study finds surprising source of social influence. University of Pennsylvania.  Jul 20, 2021. 


Douglas Guilbeault, Damon Centola.  Topological measures for identifying and predicting the spread of complex contagions. Nat Commun 12, 4430. doi: 10.1038/ s41467-021-24704-6. Jul 20  2021.


Also

1829 - catalisi d' interferenza periferica (c.i.p.)  Notes. Nov 24, 2004. (quasi-stochastic poetry).


keyword 'transition' | 'transitional' in FonT



keyword 'transition' | 'transizion*' in Notes (quasi-stochastic poetry)




martedì 20 luglio 2021

# life: some scientists hypothesize the possibility of (A) traveling faster than light, (B) visiting the interior of a black hole, (C) being already under observation by alien entities.

(A) traveling faster than light

<< Lentz (Erik Lentz. https://iopscience.iop.org/article/10.1088/1361-6382/abe692 ) proposes one such way we might be able to do this, thanks to what he calls a new class of hyper-fast solitons – a kind of wave that maintains its shape and energy while moving at a constant velocity (and in this case, a velocity faster than light). According to Lentz's theoretical calculations, these hyper-fast soliton solutions can exist within general relativity, and are sourced purely from positive energy densities, meaning there's no need to consider exotic negative- energy- density sources that haven't yet been verified. (..) With sufficient energy, configurations of these solitons could function as 'warp bubbles', capable of superluminal motion, and theoretically enabling an object to pass through space-time while shielded from extreme tidal forces. >>

<< another recent analysis, published only this month ( David Nield.  https://www.sciencealert.com/engineers-have-proposed-the-first-model-for-a-physical-warp-drive  ;  Alexey Bobrick, Gianni Martire. https://iopscience.iop.org/article/10.1088/1361-6382/abdf6e ), which also proposes an alternative model for a physically possible warp drive that doesn't require negative energy to function. >>️️

Peter Dockrill. Faster-Than-Light Travel Is Possible Within Einstein's Physics, Astrophysicist Shows. Mar 11, 2021.


(B) visiting the interior of a black hole

<<  if a person found an isolated supermassive black hole suitable for scientific study and decided to venture in, everything observed or measured of the black hole interior would be confined within the black hole's event horizon.
Keeping in mind that nothing can escape the gravitational pull beyond the event horizon, the in-falling person would not be able to send any information about their findings back out beyond this horizon. Their journey and findings would be lost to the rest of the entire universe for all time. But they would enjoy the adventure, for as long as they survived … maybe …. >>️

Leo Rodriguez, Shanshan Rodriguez. Could a human enter a black hole to study it? A person could travel past (certain) black holes' event horizons without dying immediately — here's how. Feb 7, 2021. 


(C) being already under observation by alien entities.

<< On June 25 the Pentagon and the Office of the Director of National Intelligence released their much hyped report on unidentified aerial phenomena, or UAP. (..) And while the report did not rule out an extraterrestrial origin for much of the documented UAP, it was short on details or bombshells. >> 

<<  we already know our world is easily detectable by extrasolar observers. A paper published on June 23 in Nature  
(Kaltenegger L., Faherty J.K.  https://www.nature.com/articles/s41586-021-03596-y ) shows that in the past 5,000 years, 1,715 stars have been in the right celestial position to view a populated Earth transiting the sun—with 319 more entering this sweet spot in the next 5,000 years. And seven of these far-off stars are known to have their own orbiting exoplanets that might support life. >>

<< Think of living in a room, and all the windows are open, and you do all your business, and you don’t know that all the windows are open, (..) Would you behave differently if you knew that you are being seen all your life? >>️  René Heller️
Tess Joosse. Aliens Might Already Be Watching Us. A new star map reveals more than 2,000 stars, some with their own planets, that have a direct view of our planetary presence. July 1, 2021




lunedì 19 luglio 2021

# gst: mitigate | eliminate side lobes from superoscillatory waves (to manipulate nanoparticles)

<< A sharp-edged aperture is a promising solution for eliminating side lobes from superoscillatory waves. >>

<< Optical superoscillation refers to a wave packet that can oscillate locally in a frequency exceeding its highest Fourier component. This intriguing phenomenon enables production of extremely localized waves that can break the optical diffraction barrier. >>

<< The trouble is that strong side lobes accompany the main lobes of superoscillatory waves, which limits the field of view and hinders application. >>️

<< A central microdisc with cylindrical diffraction gives rise to a superoscillatory light spot of a size within the optical diffraction limit. A pair of sharp-edged apertures ensures constructive interference with the high-spatial-frequency waves. That interference effectively eliminates side lobes along a symmetric cut that can be adjusted in the transverse plane by rotating the moonlike apertures. >>
<< the cylindrical diffraction of the central microdisc produces superoscillatory waves with Bessel-like forms. These forms enable the delicate structures of the superoscillatory waves propagating in free space to travel much farther than the evanescent light waves. (..) this intriguing propagation effect of superoscillation holds promise for potential application in nanoparticle manipulation, as well as superresolution imaging. >>️
Optical superoscillation without side waves. SPIE-International Society for Optics and Photonics. Jun 24, 2021.


Yanwen Hu, Shiwang Wang, et al. Optical superoscillatory waves without side lobes along a symmetric cut. Advanced Photonics, 3(4), 045002 doi: 10.1117/ 1.AP.3.4.045002. Jun 23, 2021. 





giovedì 15 luglio 2021

# gst: apropos of turbulence, self-similarity of turbulent flows with internal and external intermittency

<< Scientists have long used supercomputers to better understand how turbulent flows behave under a variety of conditions. Researchers have now include the complex but essential concept of 'intermittency' in turbulent flows. >>️

<< Despite its seemingly random, chaotic characteristics, researchers have identified some important properties that are universal, or at least very common, for turbulence under specific conditions. (..) Much of that important turbulent motion may stem from what happens in a thin area near the edge of the flame, where its chaotic motions collide with the smoother-flowing fluids around it. This area, the turbulent-non-turbulent interface (TNTI), has big implications for understanding turbulent mixing. >>️

<< Scientists distinguish between internal intermittency, which occurs at the smallest scales and is a characteristic feature of any fully developed turbulent flow, and external intermittency, which manifests itself at the edge of the flame and depends on the structure of the TNTI. >>️

<< For Bode and Gauding (Mathis Bode, Michael Gauding), understanding the small-scale turbulence happening at the thin boundary of the flame is the point. >>

<< Our simulations are highly resolved and are interested in these thin layers, (..) For production runs, the simulation resolution is significantly higher compared to similar DNS (direct numerical simulations ) to accurately resolve the strong bursts that are connected to intermittency. >> Mathis Bode. 
Simulations of turbulence's smallest structures. Gauss Centre for Supercomputing. Jul 8, 2021. 


<< In turbulent jet flows, the phenomenon of external intermittency originates from a sharp layer, known as the turbulent/ non-turbulent interface, that separates the turbulent core from the surrounding irrotational fluid. First, it is shown that low-order and higher-order structure functions in both the core and the shear layer of the jet satisfy complete self-preservation, which means that structure functions are invariant with time and collapse over the entire range of scales, regardless of the set of length and velocity scales used for normalization. Next, the impact of external intermittency on small-scale turbulence is studied along the cross-wise direction by the self-similarity of structure functions. It is shown that structure functions exhibit from the centre toward the edge of the flow a growing departure from self-similarity and the prediction of classical scaling theories. By analysing statistics conditioned on the turbulent portion of the jet, it is demonstrated that this departure is primarily due to external intermittency and the associated similarity-breaking effect. >>️

Michael Gauding, Mathis Bode, et al. Self-similarity of turbulent jet flows with internal and external intermittency. Journal of Fluid Mechanics.  919 , 25, A41. doi: 10.1017/ jfm.2021.399. Jun 1,  2021.


Michael Gauding, Mathis Bode, et al. On the combined effect of internal and external intermittency in turbulent non-premixed jet flames. Proceedings of the Combustion Institute. 38, (2): 2767-2774. doi: 10.1016/ j.proci.2020.08.022. Dec 9, 2020.


keyword 'Intermittency' in ScienceDirect


Also

1939 - stocastici accessi (di traslitteranti ludi). Notes. Jan 11, 2006. 
(quasi-stochastic poetry )


2064 - on responses to deviant stimuli.
Notes. Sep 26, 2006. (quasi-stochastic poetry )



giovedì 8 luglio 2021

# gst: apropos of 'disordered interactions', localization and dissociation of bound states and mapping to chaotic billiards concerning two particles on a chain

AA << consider two particles hopping on a chain with a contact interaction between them. At strong interaction, there is a molecular bound state separated by a direct gap from a continuous band of atomic states. Introducing weak disorder in the interaction, the molecular state becomes Anderson localized (exponential localization of all energy eigenstates,). At stronger disorder, part of the molecular band delocalizes and dissociates due to its hybridization to the atomic band. (AA) characterize these different regimes by computing the density of states, the inverse participation ratio, the level-spacing statistics and the survival probability of an initially localized state.  >>️

<< The atomic band is best described as that of a rough billiard for a single particle on a square lattice that shows signatures of quantum chaos. In addition to typical ``chaotic states'', (AA) find states that are localized along only one direction. These ``separatrix states'' are more localized than chaotic states, and similar in this respect to scarred states, but their existence is due to the separatrix iso-energy line in the interaction-free dispersion relation, rather than to unstable periodic orbits. >> 

Hugo Perrin, Janos K. Asboth, et al.  Two particles on a chain with disordered interaction: Localization and dissociation of bound states and mapping to chaotic billiards. arXiv: 2106.09603v1. Jun 17, 2021. 



lunedì 5 luglio 2021

# gst: apropos of (multitudes) of transitional droplets, when a liquid film collapses in a foam ...

<< Foams have unique properties that distinguish them from ordinary liquids and gases, and are ubiquitously observed in nature, both in biological systems and industrial products. >>
<< Once a crack appears near the border and a collapse front is formed, (AA) find that the curvature of the front reverses as it migrates, followed by the emergence and emission of droplets. (they) elucidate the origins of this behavior and discuss the stability of foams, establishing how the characteristic time scales of the process relate to each other. >>️

Naoya Yanagisawa, Marie Tani, Rei Kurita. Dynamics and mechanism of liquid film collapse in a foam. Soft Matter. 17, 1738-1745. Feb 17, 2021.


Also

keyword 'foam' in FonT


keyword 'collapse' in FonT


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







sabato 3 luglio 2021

# gst: emergence of the traveling chimera, imperfect-traveling, traveling multi-clusters, and alternating traveling chimera in a two-dimensional network

<< Neuronal synchronization being a phenomenon linked to several brain pathologies such as epilepsy, Parkinson diseases, Alzheimer, autism and schizophrenia, does not always appear in a singular way in neuronal networks. Its presence (state of coherence) accompanied simultaneously by an asynchronous state (state of incoherence) has been demonstrated (..) in the networks of identical oscillators not locally coupled. This phenomenon was later termed the chimera state. (..) Chimera states are analogously to the cerebral behaviors of certain aquatic mammals and migratory birds, which during their movements half part of their brains asleep while the rest are awake.  >>️

AA << study the emergence of the traveling chimera state in a two-dimensional network of (..) burst neurons with the mutual presence of local and non-local couplings. (AA) show that in the unique presence of the non-local chemical coupling modeled by a nonlinear function, the traveling chimera phenomenon occurs with a displacement in both directions of the plane of the grid. The introduction of local electrical coupling shows that the mutual influence of the two types of coupling can, for certain values, generate traveling chimera, imperfect-traveling, traveling multi-clusters, and alternating traveling chimera, ie the presence in the network under study, of patterns of coherent elements interspersed by other incoherent elements in movement and alternately changing their position over time. The confirmation of the states of coherence is done by introducing the parameter of instantaneous local order parameter in two dimensions. >>️

Gael R. Simo, Patrick Louodop, et al. Traveling chimera patterns in two-dimensional neuronal network. arXiv:2106.08400v1. Jun 9, 2021.