# chem: bizarre phase transitions in tantalum disulfide, it should be a conducting metal, but in the real world, it acts like an insulator

<< It has long been known that  crystalline materials should be good conductors when they have an odd number of electrons in each repeating cell of the structure, but may be poor conductors when the number is even. However, sometimes this formula does not work, with one case being "Mottness," a property based on the work of Sir Nevill Mott. According to that theory, when there is strong repulsion between electrons in the structure, it leads the electrons to become "localized"-paralyzed, in other words-and unable to move around freely to create an electric current. >>

<< For the current study, (..) the research group decided to look at tantalum disulfide, a material with 13 electrons in each repeating structure, which should therefore make it a conductor. However, it is not, and there has been controversy over whether this property is caused by its "Mottness" or by a pairing structure. >>

<< The exact nature of the insulating state and of the phase transitions in tantalum disulfide have been long-standing mysteries, and it was very exciting to find that Mottness is a key player, aside from the pairing of the layers. This is because theorists suspect that a Mott state could set the stage for an interesting phase of matter known as a quantum spin liquid. >> Christopher Butler. 

Jens Wilkinson. 'Tantalizing' clues about why a mysterious material switches from conductor to insulator. 

 RIKEN. May 18, 2020.

https://phys.org/news/2020-05-tantalizing-clues-mysterious-material-conductor.html   

AA << also observe the collapse of Mottness at an extrinsically re-stacked termination, demonstrating that the microscopic mechanism of insulator-metal transitions lies in degrees of freedom of inter-layer stacking. >>

C. J. Butler, M. Yoshida, et al. Mottness versus unit-cell doubling as the driver of the insulating state in 1T-TaS2. Nat Commun 11, 2477. doi: 10.1038/ s41467-020-16132-9. May 18, 2020

https://www.nature.com/articles/s41467-020-16132-9   

Also

Quantum spin liquid. 

https://en.m.wikipedia.org/wiki/Quantum_spin_liquid

# astro: oops? apropos of rapid expansion of trajectories, the nomadic escape propensity of Titan.

As a vision of a fuzzy snooker, << decades of measurements and calculations have revealed that Titan's orbit around Saturn is expanding- meaning, the moon is getting farther and farther away from the planet- at a rate about 100 times faster than expected. The research suggests that Titan was born much closer to Saturn and migrated out to its current distance of 1.2 million kilometers (about 746,000 miles) over 4.5 billion years. >>

<< Titan is expected to gravitationally squeeze Saturn with a particular frequency that makes the planet oscillate strongly, similarly to how swinging your legs on a swing with the right timing can drive you higher and higher. This process of tidal forcing is called resonance locking. Fuller (Jim Fuller) proposed that the high amplitude of Saturn's oscillation would dissipate a lot of energy, which in turn would cause Titan to migrate outward away from the planet at a faster rate than previously thought. >>

<< The resonance locking theory can apply to many astrophysical systems. I'm now doing some theoretical work to see if the same physics can happen in binary star systems, or exoplanet systems, >> Jim Fuller.

Lori Dajose. Titan is migrating away from Saturn 100 times faster than previously predicted. Jun 8, 2020.

https://phys.org/news/2020-06-titan-migrating-saturn-faster-previously.html

Valery Lainey, Luis Gomez Casajus, et al. Resonance locking in giant planets indicated by the rapid orbital expansion of Titan. Nat Astron. doi: 10.1038/ s41550-020-1120-5. Jun 8, 2020.

https://www.nature.com/articles/s41550-020-1120-5   

Also (quasi-stochastic poetry)

1648b - tenuta di rigo della sonda. Notes. Jan 15, 2005.

https://inkpi.blogspot.com/2005/01/1648b-tenuta-di-rigo-della-sonda.html

# life: apropos of widespread racism, three in four people (probably even more than three) hold unconscious negative view of world: study

<< Most Australians tested for unconscious bias hold a negative view of Indigenous Australians which can lead to widespread racism, new analysis from The Australian National University (ANU) shows. >>

<< The ANU researchers say 75 per cent of Australians tested using the Implicit Association Test by a joint initiative of universities including Harvard, Yale and the University of Sydney hold a negative implicit or unconscious bias against Indigenous Australians. >>

Three in four people hold negative view of Indigenous people: study. Australian National University. June 9, 2020.

https://phys.org/news/2020-06-people-negative-view-indigenous.html   

Siddharth Shirodkar. Bias against Indigenous Australians: Implicit association test results for Australia. Journal of Australian Indigenous Issues. Vol 22 Issue 3-4.  Dec 2019.

https://search.informit.com.au/documentSummary;dn=150032703197478;res=IELIND   

Also

# brain: immagini #CTZ, cicliche fantasmatiche pervasive visioni ricorrenti. FonT. Jun 29, 2019. 

https://flashontrack.blogspot.com/2019/06/brain-immagini-ctz-cicliche.html

# lang: an 'esperanto' language among birds

<< animals with shared predators can eavesdrop on and respond to each other's calls, indicating that they can partly understand other species. >>

<< Many birds have specific alarm calls, warning others about a predator, (..) I was studying how a specific call of a small bird named the Japanese tit, Parus minor, evokes a visual image of the predator in their minds, in particular, a snake. >> Toshitaka Suzuki.

<< But he then observed that another bird, the coal tit or Periparus ater, also often approached the experimental area during these alarm calls. >>

<< I wondered if these other birds also mentally retrieve 'snake' images from these calls. While they are in the same taxonomic group their calls are otherwise vastly different. >> Toshitaka Suzuki.

How do birds understand 'foreign' calls? Kyoto University. May 19, 2020.

https://phys.org/news/2020-05-birds-foreign.html   

Toshitaka N. Suzuki. Other Species’ Alarm Calls Evoke a Predator-Specific Search Image in Birds. Current Biology. doi: 10.1016/ j.cub.2020.04.062. May 14, 2020.

https://www.sciencedirect.com/science/article/abs/pii/S0960982220305789

Also:

keyword 'bird' in FonT:

https://flashontrack.blogspot.com/search?q=bird

a special view:  

https://flashontrack.blogspot.com/2016/06/s-brain-question-is-humans-vs-parrots.html

# GST: the behavior of motile active self-propelling matter

<< From starling aberrations to self-turbulent fluids, 'active systems' encompass a wide family of phenomena in which individual objects propel themselves forward, allowing them to display intriguing collective behaviors. (..) these objects collectively spend most of their time in one of two states, between which some intriguing behaviors can emerge. (..) these collective behaviors are determined by the ability of the self-propelling objects to swim upwards against the gravitational force, and their degrees of bottom-heaviness. For lower values of these quantities, groups of swimmers will sink to the bottom of their container just like inactive dust grains; but higher values will instead collect at the top. In between these states, smaller clusters of swimmers group at the bottom, which are fed by plumes of sinking particles. Also, porous clusters of swimmers can form, which allow individual particles to escape. >>

'Bottom-heavy squirmers' adopt characteristic group behaviours. Springer. May 28, 2020.

https://phys.org/news/2020-05-bottom-heavy-squirmers-characteristic-group-behaviours.html 

Ruhle F., Stark H. Emergent collective dynamics of bottom-heavy squirmers under gravity. Eur. Phys. J. E 43, 26 (2020). doi: 10.1140/epje/ i2020-11949-8. May 25, 2020.

https://link.springer.com/article/10.1140/epje/i2020-11949-8  

# life: the landscape of a 'patchwork' pandemic (caused by 1or2 'achoo' from Wuhan)

<< There was supposed to be a peak. But the stark turning point, when the number of daily COVID-19 cases in the U.S. finally crested and began descending sharply, never happened. Instead, America spent much of April on a disquieting plateau, with every day bringing about 30,000 new cases and about 2,000 new deaths. The graphs were more mesa than Matterhorn—flat-topped, not sharp-peaked. >>

<< What’s happening is not one crisis, but many interconnected ones. As we shall see, it will be harder to come to terms with such a crisis. It will be harder to bring it to heel. And it will be harder to grapple with the historical legacies that have shaped today’s patchwork. >>

Ed Yong. America’s Patchwork Pandemic Is Fraying Even Further. The coronavirus is coursing through different parts of the U.S. in different ways, making the crisis harder to predict, control, or understand. May 20, 2020. 

https://www.theatlantic.com/health/archive/2020/05/patchwork-pandemic-states-reopening-inequalities/611866/

# behav: persistent neuronal firing during flight in flies, like a pulsating gambler who has to decide quickly

<< A general principle of sensory systems is that they adapt to prolonged stimulation by reducing their response over time. >>

<< as opposed to most sensory and visual neurons, and in particular to the motion vision sensitive neurons in the brains of both flies and mammals, the descending neurons show little adaption during stimulus motion. (..) the optic-flow-sensitive descending neurons display persistent firing, or an after-effect, following the cessation of visual stimulation, consistent with the lingering calcium signal hypothesis. >>

AA results << show a combination of adaptation and persistent firing in the neurons that project to the thoracic ganglia and thereby control behavioral output. >>

Sarah Nicholas, Karin Nordstrom. Persistent Firing and Adaptation in Optic-Flow-Sensitive Descending Neurons. Curr Biol. doi: 10.1016/ j.cub.2020.05.019. May 28, 2020.

https://www.cell.com/current-biology/fulltext/S0960-9822(20)30658-8

Revealing how flies make decisions on the fly to survive. Flinders University. May 28, 2020

https://phys.org/news/2020-05-revealing-flies-decisions-survive.html

Also

the flexible mental maps of flies. FonT. Nov 21, 2019. 

https://flashontrack.blogspot.com/2019/11/brain-flexible-mental-maps-of-flies.html

<< Considerando invece l' immagine classica della "mosca nella bottiglia", >>  in: 2066 - voli a casaccio. Notes. (quasi-stochastic poetry). Oct 01, 2006.

https://inkpi.blogspot.com/2006/10/2066-voli-casaccio.html