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martedì 30 giugno 2020

# gst: elastic instabilities, a morphing model to quickly trap anything (in 100msec), the Venus flytrap (Dionaea muscipula)

<< The Venus flytrap (Dionaea muscipula) takes only 100 milliseconds to trap its prey. Once their leaves, which have been transformed into snap traps, have closed, insects can no longer escape. >>

<< the trap of the carnivorous plant is under mechanical prestress. In addition, its three tissue layers of each lobe have to deform according to a special pattern. >>

<< In order to close correctly, the traps also had to consist of three layers of tissue: an inner which constricts, an outer which expands, and a neutral middle layer. >>

Albert Ludwigs. Biomechanical analyses and computer simulations reveal the Venus flytrap snapping mechanisms. University of Freiburg. Jun 23, 2020.


Renate Sachse, Anna Westermeier, et al. Snapping mechanics of the Venus flytrap (Dionaea muscipula). PNAS. doi: 10.1073/ pnas.2002707117. Jun 22, 2020. 


Also

Dionaea muscipula, with precision. FonT. Feb 2, 2016. 




lunedì 29 giugno 2020

# gst: self-assembly in complex patterns during the evaporation of a sessile droplet

<< When a sessile droplet containing a solute in a volatile solvent evaporates, flow in the droplet can transport and assemble solute particles into complex patterns. >>

Bryan A. Nerger, P.-T. Brun, Celeste M. Nelson. Marangoni flows drive the alignment of fibrillar cell-laden hydrogels. Science Advances. Vol. 6, no. 24, eaaz7748. doi: 10.1126/ sciadv.aaz7748. Jun 12, 2020.


Thamarasee Jeewandara. Marangoni flows drive the alignment of fibrillar cell-laden hydrogels. Phys.org. Jun 25, 2020


Also

keyword 'Marangoni effect'





giovedì 25 giugno 2020

# life: a paradigm shift; extinction vs. evanescence, relict species, ...

<< The first "complete" paradigm of extinction was proposed as "the multigenerational, attritional loss of reproductive fitness," for which MALF is a suitable acronym. A "complete" paradigm must encompass cause, effect, and a mechanism. The primary goal of this study is to verify the new paradigm. (AA) cite four independent tests of the paradigm employing observational, experimental, and wholly theoretical techniques, >>

<< "extinction" presents certain problems with adjectival and gerund forms. (AA) do not refer to a process of "extinctioning" or "extincting" and there is no disciplinary field named "extinctionary" biology, ecology, or genetics. There are several possible verbs for extinction that treat the population or species as agent. These include "devolve," "senesce," "die off," "terminate," and "disappear," among others. However, all of these are in common use with connotations that would distract from (they) proposed meaning. "Devolve" is common in antievolutionist literature. "Senesce" is usually applied only to individuals. "Die off" does not have a single-word noun form. "Terminate" used intransitively comes close to our proposed meaning, but the popularity of the Arnold Schwarzenegger film Terminator will suggest the transitive form to most people. "Disappear" suggests something that is merely out of sight, not necessarily extinct. Instead of these common words, (they) propose using a verb with no distracting connotations. (AA) take our cue from Jefferson’s concern over extinction. Jefferson (1799:256) uses the term "evanish," or in its modern form, "vanish." The adjectival form "vanished" is usable but the noun form sounds a bit awkward: "vanishment." However, Jefferson’s "evanish" calls attention to the Latin root, e + vanescere = to pass away. "Evanesce" has an elegant noun form, "evanescence," and several adjectival forms covering a range of states: "evanesced" denoting the completed action, "evanescing" denoting an action in process, and "evanescent" denoting action in process or in potential. In physics, the adjective "evanescent" is used to designate an electromagnetic field that does not propagate waves beyond the vicinity of the source of the field. Physics and biology are sufficiently distinct that (AA) proposed usage would not create confusion. "Evanescence" does not imply an external agent performing the action and fits the understanding of extinction as a process without adding confusing connotations. This process may be a precursor or complement to evolution, but not necessarily so. >>

Delbert Wiens, Timothy Sweet, Thomas Worsley. Validating the New Paradigm for Extinction: Overcoming 200 Years of Historical Neglect, Philosophical Misconception, and Inadequate Language. The Quarterly Review of Biology. Vol. 95, Issue 2, Pages 109-124. doi: 10.1086/709086. Jun 2020.


Goodbye 'extinction,' hello 'evanescence'? Validating a new paradigm. University of Chicago. Jun 18, 2020. 



lunedì 22 giugno 2020

# bots: tiny machinery, nanobots (molecule-sized bots) from 1k to millions swarming together to perform tasks

<< Multi-disciplinary research has led to the innovative fabrication of molecule-sized robots. Scientists are now advancing their efforts to make these robots interact and work together in the millions. >>

AA << have made molecular robots with three key components: microtubules, single-stranded DNA, and a light-sensing chemical compound. The microtubules act as the molecular robot's motor, converting chemical energy into mechanical work. The DNA strands act as the information processor due to its incredible ability to store data and perform multiple functions simultaneously. The chemical compound, azobenzene derivative, is able to sense light, acting as the molecular robot's on/off switch. (..) (They) have successfully controlled the shape of those swarms by tuning the length and rigidity of the microtubules. Relatively stiff robots swarm in uni-directional, linear bundles, while more flexible ones form rotating, ring-shaped swarms.>>

<< A continuing challenge, though, is making separate groups of robots swarm at the same time, but in different patterns. This is needed to perform multiple tasks simultaneously. >>

Scientists working to make molecule-sized robots swarm together to perform tasks. National Institute for Materials Science. Jun 18, 2020.


Arif Md. Rashedul Kabir, Daisuke Inoue,  Akira Kakugo. Molecular swarm robots: recent progress and future challenges.  Science and Technology of Advanced Materials. 21:1, 323-332. doi: 10.1080/ 14686996.2020.1761761. Jun 16, 2020. 


Also

keyword 'bot' in FonT





sabato 20 giugno 2020

# life: unaware racisms

<< racism is about action in everyday life, not just words or hashtags at a time of uprising. We can be careful about what we say – language is conscious and controllable. But it is perfectly possible to hold deep-seated racist views, sometimes subconsciously, and simultaneously announce you are definitely not racist. >>

Geoff Beattie. Black Lives Matter: you may be a vocal supporter and still hold racist views. Jun 17, 2020


Also

keyword "CTZ" in FonT



giovedì 18 giugno 2020

# gst: critical points seem to act behind the complex behavior of collectives.

<< Current experiments support the controversial hypothesis that a well-known concept in physics—a critical point—is behind the striking behavior of collective animal systems. >>

AA << showed that light-controlled microswimming particles can be made to organize into collective states such as swarms and swirls. By studying the particles fluctuating between these states, they provide evidence for critical behavior—and support for a physical principle underlying the complex behavior of collectives.>>

<< What we observed is that the system can make sudden transitions from one state to the other, which demonstrates the flexibility needed to react to an external perturbation like a predator, (..) and provides clear evidence for a critical behavior. >> Clemens Bechinger

<< Through very simple interactions, they have shown that you can tune a physical system to a collective state - criticality - of balance between order and disorder. >> Iain Couzin

Physics principle explains order and disorder of swarms. University of Konstanz. Jun 11, 2020.


Bauerle T., Loffler R.C., Bechinger C. Formation of stable and responsive collective states in suspensions of active colloids. Nat Commun 11, 2547. doi: 10.1038/ s41467-020-16161-4. May 21, 2020.


Also 

keyword 'self-assembly' in FonT




martedì 16 giugno 2020

# life: apropos of extreme swing (5); POTUSrace, he will accept a hypothetical defeat or, conversely, he will not

<< Joe Biden said Wednesday night that he believes if President Donald Trump loses the election and refuses to leave the White House, many of the former generals who used to work for him "will escort him from the White House with great dispatch." >>

<< "Mark my words I think he is gonna try to kick back the election somehow, come up with some rationale why it can't be held," Biden said in April. But the real danger here is not that Trump changes the date of the general election, which is virtually impossible, or that he seeks to claims squatter's rights in the White House. The thing that could threaten Biden's potential presidency -- and the ability of the country to move on from what will be one of the nastiest elections in modern history -- is if Trump simply refuses to admit he lost, never conceding that Biden is the fair-and-square president.>>

<< And it's very easy to imagine Trump -- with his 80-plus million Twitter followers and the potential that he would be the head of a TV network post-presidency -- beating the drum of illegitimacy day in and day out. Because, well, it is in his interest to do so and, as he has shown repeatedly during his presidency, he has very little regard for either the office or its status as a moral beacon within the country and the world. The result isn't hard to imagine: An even deeper divide within the country between the Trumpists and everyone else. >>

Chris Cillizza. Here's the real danger if Donald Trump loses the 2020 election. Updated 1513 GMT (2313 HKT) June 11, 2020.


Also (quasi-stochastic poetry)

2151 - a voting machine (to explain precisely). Notes. Jan 15, 2008.




lunedì 15 giugno 2020

# evol: traces of weird evolution, ancient crocodiles walked on two legs, like dinosaurs

<< some species of ancient crocodiles walked on their two hind legs like dinosaurs and measured over three meters in length. >>

<< At one site, the footprints were initially thought to be made by a giant bipedal pterosaur walking on the mudflat, we now understand that these were bipedal crocodile prints, (..) "And while footprints were everywhere on the site, there were no handprints. (..) Dinosaurs and their bird descendants walk on their toes. Crocodiles walk on the flat of their feet leaving clear heel impressions, like humans do. >> Anthony Romilio.

Ancient crocodiles walked on two legs like dinosaurs. University of Queensland. Jun 11, 2020.


Kim, K.S., Lockley, M.G., et al. Trackway evidence for large bipedal crocodylomorphs from the Cretaceous of Korea. Sci Rep 10, 8680. doi: 10.1038/ s41598-020-66008-7. 



sabato 13 giugno 2020

# 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.


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







venerdì 12 giugno 2020

# 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.


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.


Also (quasi-stochastic poetry)

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





giovedì 11 giugno 2020

# 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.


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


Also

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


mercoledì 10 giugno 2020

# 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.


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.


Also:

keyword 'bird' in FonT:


a special view:  


venerdì 5 giugno 2020

# 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.


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.



giovedì 4 giugno 2020

# 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. 


mercoledì 3 giugno 2020

# 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.


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


Also

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


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



lunedì 1 giugno 2020

# life; aprops of 'extreme swing' (4) ... IT exists, IT doesn't; IT will return, IT will not;

<< "i tamponi eseguiti negli ultimi dieci giorni hanno una carica virale infinitesimale rispetto a quelli eseguiti su pazienti di un mese, due mesi fa". Il presidente del Consiglio Superiore di Sanità (..) esprime "sorpresa e sconcerto" >>

Per il primario del San Raffaele, il coronavirus "dal punto di vista clinico non esiste più". AGI. May 31, 2020 utd 21:03 


Also

keyword 'extreme | swing' in FonT


keyword 'estremo | swing' in Notes (quasi- stochastic poetry)