Translate

giovedì 16 maggio 2019

# math: squeezing Moebius strips using either 'tame' or 'wild' embeddings, but only with overlaps

<< In math, three-dimensional space sprawls out to infinity in every direction. With an infinite amount of room, it should be able to hold an infinite number of things inside of it - pearls, peacocks or even planets. >>

<< But a recent proof (..), shows that one relatively well-known mathematical object can’t be packed an uncountably infinite number of times into an infinite amount of space: the Möbius band, a two-dimensional loop with a half-twist. >>

<< "Tame" embeddings extend to the entire space, so it’s possible to stretch or squish the space to make the embedded sphere into a standard round sphere. >>

<< "Wild" embeddings, on the other hand, are not so easily visualized and generally require some infinite process to describe. With a wild embedding, there is no way to transform the space to make the wildly embedded version a round sphere. >>

Evelyn Lamb. Möbius Strips Defy a Link With Infinity. Feb 20, 2019.

https://www.quantamagazine.org/mobius-strips-defy-a-link-with-infinity-20190220

https://twitter.com/QuantaMagazine/status/1126601994494455809

Olga D. Frolkina. Pairwise disjoint Moebius bands in space. Journal of Knot Theory and Its Ramifications. Vol. 27, No. 09, 1842005 (2018). doi: 10.1142/S0218216518420051

https://www.worldscientific.com/doi/abs/10.1142/S0218216518420051

mercoledì 15 maggio 2019

# brain eye: having colorful visions even in near darkness

<< some fish contained multiple rod opsins raising the possibility they have rod-based color vision. >>

Color vision found in fish that live in near darkness. University of Maryland. May 9, 2019.

https://m.phys.org/news/2019-05-remarkable-fish-deep-dark.html

Zuzana Musilova, Fabio Cortesi, et al. Vision using multiple distinct rod opsins in deep-sea fishes. Science. May 10, 2019 Vol. 364, Issue 6440, pp. 588-592 doi: 10.1126/science.aav4632

https://science.sciencemag.org/content/364/6440/588

domenica 12 maggio 2019

# game gst: anomalous coexistence of cooperators and defectors and unexpected selection reversal in the hawk-dove game.

<< Evolution occurs in populations of reproducing individuals. Reproduction depends on the payoff a strategy receives. The payoff depends on the environment that may change over time, on intrinsic uncertainties, and on other sources of randomness. These temporal variations in the payoffs can affect which traits evolve. >>

AA << study the impact of arbitrary amplitudes and covariances of temporally varying payoffs on the dynamics. The evolutionary dynamics may be "unfair," meaning that, on average, two coexisting strategies may persistently receive different payoffs. This mechanism can induce an anomalous coexistence of cooperators and defectors in the prisoner’s dilemma, and an unexpected selection reversal in the hawk-dove game. >>

Frank Stollmeier, Jan Nagler. Unfair and Anomalous Evolutionary Dynamics from Fluctuating Payoffs. Phys. Rev. Lett. 120, 058101  Feb 1,  2018.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.120.058101

venerdì 10 maggio 2019

# evol: an irrefutable evidence that they rose from the dead by an 'iterative evolution' process

<< the last surviving flightless species of bird, a type of rail, in the Indian Ocean had previously gone extinct but rose from the dead thanks to a rare process called 'iterative evolution'. >>

<< This is the first time that iterative evolution (the repeated evolution of similar or parallel structures from the same ancestor but at different times) has been seen in rails and one of the most significant in bird records. >>

The bird that came back from the dead. University of Portsmouth. May 9, 2019.

https://m.phys.org/news/2019-05-bird-dead.html

<< Fossil evidence presented here is unique for Rallidae and epitomizes the ability of birds from this clade to successfully colonize isolated islands and evolve flightlessness on multiple occasions. >>

Julian P Hume, David Martill. Repeated evolution of flightlessness in Dryolimnas rails (Aves: Rallidae) after extinction and recolonization on Aldabra. Zoological Journal of the Linnean Society, zlz018.  doi: 10.1093/zoolinnean/zlz018. May 8, 2019.

https://academic.oup.com/zoolinnean/advance-article-abstract/doi/10.1093/zoolinnean/zlz018/5487031

giovedì 9 maggio 2019

# trade: happy commerce (also on a galactic scale) with a hypothetical "S-money"

<< A new type of money that allows users to make decisions based on information arriving at different locations and times, and that could also protect against attacks from quantum computers, has been proposed by a researcher at the University of Cambridge. >>

<< The theoretical framework, dubbed 'S-money', could ensure completely unforgeable and secure authentication, and allow faster and more flexible responses than any existing financial technology, harnessing the combined power of quantum theory and relativity. In fact, it could conceivably make it possible to conduct commerce across the Solar System and beyond, without long time lags, although commerce on a galactic scale is a fanciful notion at this point. >>

S-money: Ultra-secure form of virtual money proposed. University of Cambridge. May 7, 2019

https://m.phys.org/news/2019-05-s-money-ultra-secure-virtual-money.html

Adrian Kent. S-money: virtual tokens for a relativistic economy. Proceedings of the Royal Society A doi: 10.1098/rspa.2019.0170  May 8, 2019.

https://royalsocietypublishing.org/doi/10.1098/rspa.2019.0170

Also

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

mercoledì 8 maggio 2019

# brain: changing like a skilled jazz player

<< The new findings are just the latest evidence that our brains are capable of changing in response to experiential learning from a very early age, (..) but that there are underlying constraints hardwired into the brain that shape and guide how those changes unfold. Like a skilled jazz player who spontaneously invents fresh melodies while still respecting the grammar of music, the brain is a master improviser that can create new activations (..), but it must still follow certain rules-like those regarding objects preferentially viewed with our central gaze-about where these category-preferring activations can take place. >> Kalanit Grill-Spector.

Ker Than. Researchers identify brain region activated by Pokemon characters. Stanford University. May 6, 2019.

https://m.medicalxpress.com/news/2019-05-brain-region-pokemon-characters.html

Jesse Gomez, Michael Barnett, Kalanit Grill-Spector. Extensive childhood experience with Pokémon suggests eccentricity drives organization of visual cortex. Nature Human Behaviour. doi: 10.1038/s41562-019-0592-8. May 6, 2019

https://www.nature.com/articles/s41562-019-0592-8

Also

"jazz"

https://inkpi.blogspot.com/search?q=jazz

lunedì 6 maggio 2019

# gst art: an image of chaotic hydrodynamics, by "Leo"

<< One of the first to visualize these flows was scientist, artist, and engineer Leonardo da Vinci, who combined keen observational skills with unparalleled artistic talent to catalog turbulent flow phenomena. Back in 1509, Leonardo was not merely drawing pictures. He was attempting to capture the essence of nature through systematic observation and description. In this figure,  https://cdn.arstechnica.net/wp-content/uploads/2018/10/daVinciWake.png   we see one of his studies of wake turbulence, the development of a region of chaotic flow as water streams past an obstacle. >>

Lee Phillips. Turbulence, the oldest unsolved problem in physics. The flow of water through a pipe is still in many ways an unsolved problem. Oct 10, 2018.

https://arstechnica.com/science/2018/10/turbulence-the-oldest-unsolved-problem-in-physics/