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giovedì 26 settembre 2019

# life: the generation of multiple bubbles mediated by gerrymandering could self trapped in deadlock

AA << analysis provides an account of the vulnerabilities of collective decision-making to systematic distortion by restricted information flow. >>

The analysis << also highlights a group-level social dilemma: information gerrymandering can enable one party to sway decisions in its favour, but when multiple parties engage in gerrymandering the group loses its ability to reach consensus and remains trapped in deadlock. >>

Alexander J. Stewart, Mohsen Mosleh, et al. Information gerrymandering and undemocratic decisions. Nature. volume 573, pages 117–121 Sep 4,  2019.     https://www.nature.com/articles/s41586-019-1507-6    

Alexander J. Stewart, Joshua B. Plotkin. Here’s what happens when political bubbles collide. Sep 4, 2019.     https://theconversation.com/heres-what-happens-when-political-bubbles-collide-121856  

Also

keyword "bubble" in: FonT  https://flashontrack.blogspot.com/search?q=bubble

Also

<< dell' ombre a bolle di neurodiscoide di ghiozzo >> in: 1813b - alea in psichedelico catino.  https://inkpi.blogspot.com/2005/03/1813b-alea-in-psichedelico-catino.html

martedì 24 settembre 2019

# gst: apropos of weak bonds, hydrophobic cohesion to stabilize the double helix of DNA

<< The main stabilizer of the DNA double helix is not the base-pair hydrogen bonds but coin-pile stacking of base pairs, whose hydrophobic cohesion, requiring abundant water, indirectly makes the DNA interior dry so that hydrogen bonds can exert full recognition power. (..) (AA) speculate that hydrophobic catalysis is a general phenomenon in DNA enzymes. >>

<< The forces that stabilize the DNA double helix are a prerequisite for the secure storage of genetic information but their modest strength is also necessary for the efficient processes of replication, transcription, recombination, and repair systems-wherein thermal fluctuations, or "breathing," play an important role >>

Bobo Feng, Robert P. Sosa, et al. Hydrophobic catalysis and a potential biological role of DNA unstacking induced by environment effects. PNAS.  116 (35) 17169-17174; Aug 27, 2019.  doi: 10.1073/ pnas.1909122116.    https://www.pnas.org/content/116/35/17169

DNA is held together by hydrophobic forces. Chalmers University of Technology. Sep 23, 2019.     https://m.phys.org/news/2019-09-dna-held-hydrophobic.html   

lunedì 23 settembre 2019

# gst: the hypothesis of a first order phase transition (a type of abrupt phase transition) to originate black holes observed by LIGO/Virgo in binary mergers.

<<  To summarize, motivated by the ~10 M* (mass similar to that of the sun) black holes observed by LIGO/Virgo in binary mergers, (AA) entertained the possibility that the quark-gluon confinement phase transition was first order due to the effect of 6 light quarks. The larger number of light quarks, compared to the standard case, pushes the transition temperature below ∼100 MeV. The first order nature of the transition significantly improves the likelihood of forming primordial black holes and its lower temperature suggests that these black holes can potentially be as heavy as ∼10 M*, compared to ∼M* for the standard QCD transition. >>

Hooman Davoudiasl.  LIGO/Virgo Black Holes from a First Order Quark Confinement Phase Transition. Phys. Rev. Lett. 123, 101102. Sep 6, 2019.   https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.123.101102  

Ingrid Fadelli. Theory proposes that LIGO/Virgo black holes originate from a first order phase transition. Sep 23, 2019.    https://m.phys.org/news/2019-09-theory-ligovirgo-black-holes-phase.html  

QCD = quantum chromodynamic  
https://en.m.wikipedia.org/wiki/Standard_Model

sabato 21 settembre 2019

# gst: dealing with bistability (through hyperbolic paraboloid origami)

<< Origami offers an avenue to program three-dimensional shapes via scale-independent and non-destructive fabrication. >>

Using theoretical model, << which connects geometry to mechanics, (AA) prove that a folded hypar origami exhibits bistability between two symmetric configurations. Further, (AA) tessellate the hypar origami and harness its bistability to encode multi-stable metasurfaces with programmable non-Euclidean geometries. >>

Ke Liu, Tomohiro Tachi, Glaucio H. Paulino. Invariant and smooth limit of discrete geometry folded from bistable origami leading to multistable metasurfaces. Nature Comm. volume 10, Article number: 4238, 17 Sep 17, 2019.    https://www.nature.com/articles/s41467-019-11935-x  

Josh Brown. Hyperbolic paraboloid origami harnesses bistability to enable new applications. Georgia Institute of Technology. Sep 17, 2019.    https://m.techxplore.com/news/2019-09-hyperbolic-paraboloid-origami-harnesses-bistability.html 

domenica 15 settembre 2019

# astro: test the 'no-hair' hypothesis on coalescent black holes (at the ~ 10% or ~ 20% levels)

<< Agreement between the postinspiral measurements of mass and spin and those using the full waveform supports the hypothesis that the GW150914 merger produced a Kerr black hole, as predicted by general relativity, and provides a test of the no-hair theorem at the ∼10% level. An independent measurement of the frequency of the first overtone yields agreement with the no-hair hypothesis at the ∼20% level.  >>

Maximiliano Isi, Matthew Giesler, et al. Testing the No-Hair Theorem with GW150914. Phys. Rev. Lett. 123, 111102. Sep 12, 2019.    https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.123.111102

Synopsis: Hunting for Hair on Coalescing Black Holes. A fresh look at data from the first detected black-hole merger supports the “no hair” theorem.  Sep 12, 2019.   https://physics.aps.org/synopsis-for/10.1103/PhysRevLett.123.111102

'No-hair' theorem   https://en.m.wikipedia.org/wiki/No-hair_theorem

Kerr black hole   https://en.m.wikipedia.org/wiki/Rotating_black_hole

sabato 14 settembre 2019

# gst: nano entities that are both twisted and untwisted at the same time

<< Scientists who study the nanoscale-with molecules and materials 10,000 smaller than a pinhead-need to be able to test the way that some molecules twist, known as their chirality, because mirror image molecules with the same structure can have very different properties. >>

<< Recently, a new class of nanoscale materials have been developed to help distinguish the chirality of molecules. These so-called 'nanomaterials' usually consist of tiny twisted metal wires, that are chiral themselves. However, it has become very hard to distinguish the twist of the nanomaterials from the twist of the molecules they are supposed to help study. >>

To solve this problem AA << created a nanomaterial that is both twisted and it is not. This nanomaterial has equal number of opposite twists—meaning they cancel each other out.  >>

<< Using a mathematical analysis of the material's symmetry properties, the team discovered a few special cases, which can bring the 'hidden' twist to light and allow very sensitive detection of chirality in molecules. >>

Chris Melvin. Scientists create a nanomaterial that is both twisted and untwisted at the same time. University of Bath. Sep 13, 2019   https://m.phys.org/news/2019-09-scientists-nanomaterial-untwisted.html  

Christian Kuppe,  Xuezhi Zheng, et al. Measuring optical activity in the far-field from a racemic nanomaterial: diffraction spectroscopy from plasmonic nanogratings. Nanoscale Horizons.  Issue 5, 2019.  doi: 10.1039/C9NH00067D.   https://pubs.rsc.org/en/content/articlelanding/2019/NH/C9NH00067D

mercoledì 11 settembre 2019

# gst: apropos to try numerically to discover states with desired response properties in chaotic (i.e. normal - ab.normal) systems, by Hridesh, Deng, Jean-Jacques, Jeremy.

  <<
Systems with many stable configurations abound in nature, both in living and inanimate matter. Their inherent nonlinearity and sensitivity to small perturbations make them challenging to study, particularly in the presence of external driving, which can alter the relative stability of different attractors. Under such circumstances, one may ask whether any clear relationship holds between the specific pattern of external driving and the particular attractor states selected by a driven multistable system. To gain insight into this question, (AA)  numerically study driven disordered mechanical networks of bistable springs which possess a vast number of stable configurations arising from the two stable rest lengths of each spring, thereby capturing the essential physical properties of a broad class of multistable systems.  (AA) find that the attractor states of driven disordered multistable mechanical networks are fine-tuned with respect to the pattern of external forcing to have low work absorption from it. Furthermore,  (AA)  find that these drive-specific attractor states are even more stable than expected for a given level of work absorption.  (AA)  results suggest that the driven exploration of the vast configuration space of these systems is biased towards states with exceptional relationship to the driving environment, and could therefore be used to 'discover' states with desired response properties in systems with a vast landscape of diverse configurations.
  >>

Hridesh Kedia, Deng Pan, et al. Drive-specific adaptation in disordered mechanical networks of bistable springs. arXiv:1908.09332v1 [nlin.AO] Aug 25, 2019.    https://arxiv.org/abs/1908.09332 

Also

keyword "three" in: FonT    https://flashontrack.blogspot.com/search?q=three

keyword "three" in: Notes      https://inkpi.blogspot.com/search?q=three

sabato 7 settembre 2019

# gst: leading to an order-disorder transition to design of decentralized swarm systems.

<< Adaptive collective behavior underpinned by specialized optimization strategies is ubiquitous in the natural world. (AA) develop a minimal model of agents that explore their environment by means of sampling trajectories. (..) (They) find that, as cognitive agents build and update their internal, cognitive representation of the causal structure of their environment, complex patterns emerge in the system (..) Exchange of information among the agents leads to an order-disorder transition. As a result of the spontaneous breaking of translational symmetry, a Goldstone mode emerges, which points at a collective mechanism of information transfer >>

Hannes Hornischer, Stephan Herminghaus, Marco G. Mazza. Structural transition in the collective behavior of cognitive agents. Scientific Reports. volume 9, Article number: 12477 (2019).   https://www.nature.com/articles/s41598-019-48638-8 

Nature's most beautiful performances could inspire the next generation of artificial intelligence. Loughborough University. Sep 6, 2019.    https://m.techxplore.com/news/2019-09-nature-beautiful-artificial-intelligence.html  

venerdì 6 settembre 2019

# gst: apropos of swirling granular media, a geometric frustration; will these entities turn left or right?

<< Granular material in a swirled container exhibits a curious transition as the number of particles is increased: At low densities, the particle cluster rotates in the same direction as the swirling motion of the container, while at high densities it rotates in the opposite direction.  >>

AA << show that the transition to counterrotation is friction dependent. At high particle densities, frictional effects result in geometric frustration, which prevents particles from cooperatively rolling and spinning. Consequently, the particle cluster rolls like a rigid body with no-slip conditions on the container wall, which necessarily counterrotates around its own axis. Numerical simulations verify that both wall-disk friction and disk-disk friction are critical for inducing counterrotation. >>

Lisa M. Lee, John Paul Ryan, et al. Geometric frustration induces the transition between rotation and counterrotation in swirled granular media. Phys. Rev. E 100, 012903. July 8, 2019.     https://journals.aps.org/pre/abstract/10.1103/PhysRevE.100.012903  

Leah Burrows. Solving the pancake problem. Harvard University. Aug 30, 2019.    https://m.phys.org/news/2019-08-pancake-problem.html  

giovedì 5 settembre 2019

# game: exploitation; a theoretical scenario in which victims (chaotically?) will cooperate

<< A new analysis of the famous game-theory puzzle finds that even when the players seem equal, one can learn to profit at the other’s expense-and the victim will cooperate. >>

Prisoner’s dilemma shows exploitation is a basic property of human society. Emerging Technology from the arXiv. May 30, 2019.

https://www.technologyreview.com/s/613585/prisoners-dilemma-shows-how-exploitation-is-a-basic-property-of-human-society/  

Yuma Fujimoto, Kunihiko Kaneko.  Emergence of Exploitation as Symmetry Breaking in Iterated Prisoner's Dilemma. arXiv: 1905.06602v1 [math.OC] May 16, 2019.

https://arxiv.org/abs/1905.06602  

lunedì 2 settembre 2019

# geo gst: even small flank failures can cause large tsunamis

<< Volcanogenic tsunamis are one of the deadliest volcanic phenomena. >>

<< Small flank failures causing large tsunamis represent a vastly underappreciated geohazards-current tsunami monitoring systems do not monitor for this kind of volcanic activity, instead focusing on large earthquakes or proxies related to unusual increases in magma intrusion.  >>

<< This collapse was captured in unprecedented detail by satellite remote sensing, providing an opportunity to understand the collapse of the volcano (Anak Krakatau volcano,  Indonesia) in a way that has not previously been possible at any volcanic island in the world. >>

Reconstructing the Anak Krakatau flank collapse that caused the December 2018 Indonesian tsunami. Geological Society of America. Aug 30, 2019.   https://m.phys.org/news/2019-08-reconstructing-anak-krakatau-flank-collapse.html   

<< the volume of material initially lost from the volcano flank failure (..) was relatively small (~0.1 km3) compared to the overall changes observed during the entire eruption, but it was nonetheless able to generate rapid tsunami waves with devastating impacts. The flank failure also changed the eruption style and the upper volcanic plumbing system, with the subsequent explosive eruptions destroying the summit and then partially rebuilding the lost flank.  >>

Rebecca Williams, Pete Rowley, Matthew C. Garthwaite. Reconstructing the Anak Krakatau flank collapse that caused the December 2018 Indonesian tsunami. Geology. doi.org/10.1130/G46517.1. Aug 30, 2019.    https://pubs.geoscienceworld.org/gsa/geology/article-abstract/573356/reconstructing-the-anak-krakatau-flank-collapse