sabato 27 febbraio 2021

# life: even when you play classic (e.g. Montezuma's Revenge), bots win.

<< A team of researchers (..) has developed a set of learning algorithms that proved to be better at playing classic video games than human players or other AI systems. >>

They << explain how their algorithms differ from others and why they believe they have applications in robotics, language processing and even designing new drugs. >>

<< Reinforcement learning algorithms learn how to do things by synthesizing information provided in a large dataset- they recognize patterns and use them to make guesses about new data. (..) But, (..) such algorithms tend to run into trouble when they encounter data that does not fit with other data in the dataset. (AA) have overcome this problem by adding an algorithm that remembers all the paths a previous algorithm has taken as it has tried to solve a problem. When it finds a data point that does not appear to be correct, it goes back to its memory map and tries another route. In terms of playing video games, it retains screen grabs as it plays and when it finds itself losing, goes back to another point in the game and tries another approach. The algorithm also groups together images that look similar to figure out what point in time it should return to if things go awry. >>

<< They then used their system to play 55 Atari games that, over time, have become benchmarks for testing AI systems. The new system beat other AI systems 85.5 percent of the time. It did particularly well at Montezuma's Revenge, scoring higher than any other AI system and beating the record for a human. >>

Bob Yirka. Reinforcement learning algorithms score higher than humans, other AI systems at classic video games. Feb 25, 2021.


Ecoffet A, Huizinga J, et al. First return, then explore. Nature 590, 580–586. doi: 10.1038/ s41586-020-03157-9. Feb 25, 2021.


Also

keyword 'AI' | 'bot' in FonT



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










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giovedì 25 febbraio 2021

# life: apropos of tricks, 'torpor', a survival strategy not as rare as previously thought

<< Life is hard for small animals in the wild, but they have many solutions to the challenges of their environment. One of the most fascinating of these strategies is torpor. Not, to be confused with sleep or Sunday afternoon lethargy, torpor is a complex response to the costs of living. >>

<<  Once thought to occur only in birds and mammals in the Northern Hemisphere where winters are more pronounced, (AA) now know torpor is widespread in small Australian mammals, and has also been observed in many small Australian bird species. >>

<<  The question people often ask about torpor, is "can humans do it?" Interestingly, some small primates have been observed using torpor. While it is technically possible to induce torpor in humans chemically, torpor is a very complex physiological process, and there are many aspects of it scientists still don't fully understand. >>

Chris Wacker. Torpor: a neat survival trick once thought rare in Australian animals is actually widespread. The Conversation. Dec 29, 2020. 



Also

Hrvatin S., Sun S., Wilcox OF et al. Neurons that regulate mouse torpor. Nature 583, 115–121. doi: 10.1038/ s41586-020-2387-5. Jun 11, 2020.


Takahashi TM, Sunagawa GA, et al. A discrete neuronal circuit induces a hibernation-like state in rodents. Nature 583, 109–114. doi: 10.1038/ s41586-020-2163-6. Jun 11, 2020.






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mercoledì 24 febbraio 2021

# gst: apropos of 'transitions', slow dynamics of complex connected networks can control the rate of demixing

<< A space- spanning network structure is a basic morphology in phase separation of soft and biomatter, alongside a droplet one. Despite its fundamental and industrial importance, the physical principle underlying such network- forming phase separation remains elusive. >>

AA << find that phase- separation dynamics is controlled by mechanical relaxation of the network- forming dense phase, whose limiting process is permeation flow of the solvent for colloidal suspensions and heat transport for pure fluids. This universal coarsening law would contribute to the fundamental physical understanding of network-forming phase separation. >>

Michio Tateno, Hajime Tanaka. Power-law coarsening in network-forming phase separation governed by mechanical relaxation. Nat Commun 12, 912. doi: 10.1038/  s41467-020-20734-8. Feb 10,  2021.

️
Discovery of a new law of phase separation. University of Tokyo. Feb 10, 2021. 


Also

keyword 'transition' in FonT


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







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martedì 23 febbraio 2021

# gst: a slow motion can triggers strong, fast-slip (many miles away)

<< At a glacier near the South Pole, earth scientists have found evidence of a quiet, slow-motion fault slip that triggers strong, fast-slip earthquakes many miles away,  >>

<< During an earthquake, a fast slip happens when energy builds up underground and is released quickly along a fault. Blocks of earth rapidly slide against one another. However, at an Antarctic glacier called Whillans Ice Plain, (they) show that "slow slips" precede dozens of large magnitude 7 earthquakes. >>

<< We found that there is almost always a precursory 'slow slip' before an earthquake, >> Grace Barcheck.

<< these slow-slip precursors- occurring as far as 20 miles away from the epicenter- are directly involved in starting the earthquake. >>

<< These slow slips are remarkably common, (..) and they migrate toward where the fast earthquake slip starts. >>

<< Within a period of two months in 2014, the group captured 75 earthquakes at the bottom of the Antarctic glacier. Data from GPS stations indicated that 73- or 96% - of the 75 earthquakes showed a period of precursory slow motion. >>

Blaine Friedlander. Slow motion precursors give earthquakes the fast slip. Cornell University. Feb 16, 2021.
️

G. Barcheck, E. Brodsky, et al. Migratory earthquake precursors are dominant on an ice stream fault. Science Advances. Vol. 7, no. 6, eabd0105. doi: 10.1126/ sciadv.abd0105. Feb 5, 2021.





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venerdì 19 febbraio 2021

# life: to eat each other's wings within mating pairs (among wood-feeding cockroaches Salganea taiwanensis)

 << The behavior of eating their mates or a part of their mate's body has been studied in sexual cannibalism or nuptial feeding. In these behaviors, only one sex eats the other unilaterally. Within mating pairs of a wood‐feeding cockroach (Salganea taiwanensis), males and females eat the mate's wings each other, which is the first “mutual” case in these behaviors. Because the evolution of sexual cannibalism and nuptial feeding has been explained based on unilaterality, this mutual eating should have a new significance of reproduction. >> 

Haruka Osaki, Eiiti Kasuya. Mutual wing-eating between female and male within mating pairs in wood‐feeding cockroach. doi: 10.1111/eth.13133. Jan 25, 2021.


Bob Yirka. Wood-eating cockroach couples take turns eating each other's wings after mating. Feb 15, 2021.


Also

the beetle Carabaeus lamarcki, dancer and sky analyzer. May 14, 2016.


2022 - si risvegliano stercorari. Notes. June 17, 2006. (quasi-stochastic poetry)


keyword 'cockroach' in FonT







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martedì 9 febbraio 2021

# zoo; apropos of extreme dwarf entities, the nano-chameleon (Brookesia nana)

<< An international team, (..) has discovered a minuscule new species of chameleon.  (..) They have named the new species Brookesia nana. >>

 << At a body length of just 13.5 mm and a total length of just 22 mm including the tail, the male nano-chameleon is the smallest known male of all 'higher vertebrates' >> Frank Glaw.

<< Unfortunately, the habitat of the Nano-Chameleon is under heavy pressure from deforestation, but the area has recently been designated as a protected area, and hopefully that will enable this tiny new chameleon to survive, >> Oliver Hawlitschek.

Meet the nano-chameleon, a new contender for the title of world's smallest reptile. Staatliche Naturwissenschaftliche Sammlungen Bayerns. Feb 01, 2021. 


Glaw, F., Kohler, J., Hawlitschek, O. et al. Extreme miniaturization of a new amniote vertebrate and insights into the evolution of genital size in chameleons. Sci Rep 11, 2522. doi: 10.1038/ s41598-020-80955-1. Jan 28,  2021.



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lunedì 8 febbraio 2021

# gst; apropos of hair that can be combed, some perturbation fields, along the event horizon of extreme black holes, seem to evolve in time indefinitely

 <<  black holes can be fully characterized by only three physical quantities: their mass, spin and charge. Since they have no additional "hairy" attributes to distinguish them, black holes are said to have "no hair"—Black holes of the same mass, spin, and charge are exactly identical to each other. >> 

AA << discovered that a special kind of black hole violates black hole uniqueness, the so-called "no hair" theorem. Specifically, the team studied extremal black holes—holes that are "saturated" with the maximum charge or spin they can possibly carry. They found that there is a quantity that can be constructed from the spacetime curvature at the black hole horizon that is conserved, and measurable by a distant observer. Since this quantity depends on how the black hole was formed, and not just on the three classical attributes, it violates black hole uniqueness. This quantity constitutes "gravitational hair" and potentially measurable by recent and upcoming gravitational wave observatories like LIGO and LISA. >>

<< even though external perturbations of extreme black holes decay as they do also for regular black holes, along the event horizon certain perturbation fields evolve in time indefinitely. >>

<< The uniqueness theorems assume time independence. But the Aretakis phenomenon explicitly violates time independence along the event horizon. This is the loophole through which the hair can pop out and be combed at a great distance by a gravitational wave observatory, >> Lior Burko.

Extreme black holes have hair that can be combed. Theiss Research. Jan 26, 2021.


Lior M. Burko, Gaurav Khanna, Subir Sabharwal. Scalar and gravitational hair for extreme Kerr black holes. Phys. Rev. D 103, L021502. Jan 26, 2021.



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sabato 6 febbraio 2021

# gst: doubling phonons by subtraction of one of them (in an optical whispering-gallery microresonator)

 << What happens now when you add or subtract a single phonon? At first thought, you may expect this would simply change the average to n + 1 or n - 1, respectively, however the actual outcome defies this intuition. Indeed, quite counterintuitively, when you subtract a single phonon, the average number of phonons actually goes up to 2n.  This surprising result where the mean number of quanta doubles has been observed for all-optical photon-subtraction experiments and is observed for the first time outside of optics here. >>

<< One way to think of the experiment is to imagine a claw machine that you often see in video arcades, except that you can't see how many toys there are inside the machine. Before you agree to play, you've been told that on average there are n toys inside but the exact number changes randomly each time you play. Then, immediately after a successful grab with the claw, the average number of toys actually goes up to 2n, >> Michael Vanner. 

Adding or subtracting single quanta of sound.  Imperial College London. Jan 25, 2021. 


G. Enzian, J. J. Price, et al. Single-Phonon Addition and Subtraction to a Mechanical Thermal State. Phys. Rev. Lett. 126, 033601. Jan 21, 2021.



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