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mercoledì 30 dicembre 2020

# behav: chaotic (jazz) music generated by songbirds during non-mating seasons for opioid reward

<< when songbirds sing during non-mating seasons, it's because singing releases an opioid naturally produced in their brain —that's right, a compound with the same biological makeup of the highly addictive painkillers. >> 

<< Animals—including birds, including humans—we produce our own endogenous opioids, and they reward behaviors naturally, like sexual behavior or feeding behavior, (..) Studies show that endogenous opioids also make play rewarding. Songbirds learn their songs, and must practice. When we listened to birds practicing in flocks, it almost sounded as if they were playing around with the notes. Darwin even suggested that birds in flocks may be singing for 'their own amusement.' So, we thought if singing is a playful behavior, it should involve opioids. >> Lauren Riters. 

<< in starlings, endogenous opioid-prompted song is evolutionarily advantageous, because singing in flocks allows them an opportunity to practice their song to prepare for the mating season. It might not be the most beautiful to listen to—Riters likened their chaotic song to freeform jazz—but that's okay. To them, it's just a warm-up for when they start looking for a mate. >> 

Songbirds sing, like humans flock, for opioid reward. University of Wisconsin-Madison. Oct 02, 2020. 


Stevenson, S.A., Piepenburg, A., et al. Endogenous opioids facilitate intrinsically-rewarded birdsong. Sci Rep 10, 11083. doi: 10.1038/ s41598-020-67684-1. Jul 6, 2020.




martedì 29 dicembre 2020

# gst: complex flow patterns generated by swarms of bubbles

<< When swarms of bubbles are driven upwards through a fluid by their buoyancy, they can generate complex flow patterns in their wake. Named 'pseudo-turbulence,' these patterns are characterized by a universal mathematical relationship between the energy of flows of different sizes, and the frequency of their occurrence. This relationship has now been widely observed through 3-D simulations, but it is less clear whether it would still hold for 2-D swarms of bubbles. >>

AA << show that in 2-D simulated fluids, this pattern changes within larger-scale flows in less viscous fluids. (..) In the past, many studies of pseudo-turbulence have found the statistical properties of 3-D bubble swarms remain universal over a wide range of bubble surface tensions, fluid viscosities, and density ratios between bubbles and fluids. In 2-D fluids, however, an effect named an 'inverse energy cascade' enables energy to be transferred from small- to large-scale flows. >>

Characterising complex flows in 2-D bubble swarms. Springer. Dec 4, 2020



Rashmi Ramadugu, Vikash Pandey, Prasad Perlekar. Pseudo-turbulence in two-dimensional buoyancy-driven bubbly flows: A DNS study. The European Physical Journal E. V 43, no. 73. doi: 10.1140/ epje/i2020-11997-0. Nov 25, 2020.


Also

keyword 'bubble' in FonT





sabato 26 dicembre 2020

# life: ten forecasts for 2021, by Saxo Bank.











Pierandrea Ferrari. I 10 cigni neri del 2021. Quali sono gli eventi inaspettati che potrebbero impattare sull’economia globale nel corso del 2021? Ecco la lista stilata da Saxo Bank.  Dec 26, 2020.




martedì 22 dicembre 2020

# gst: disorder can induce and modulate topological structures

 << One of the boons of topological insulators is that their conducting edge states are protected from disorder in the material’s structure. Turn up the disorder too much, however, and these topological features are usually lost. In 2018, experiments demonstrated the opposite behavior: in so-called topological Anderson insulators (TAIs), the addition of disorder can generate protected edge states, turning a trivial insulator into a topological one. Now, a team (..) reports a new type of TAI realized in a photonic crystal. Their experiments show that the crystal exhibits a wealth of topological phenomena that hadn’t been seen previously. >> 

Matteo Rini. Let Disorder Dictate Topology. Physics 13, s123. Sep 24, 2020. 


 AA << directly observe the disorder-induced topological phase transition from a trivial insulator to a TAI with robust chiral edge states. (They) also demonstrate topological heterostructures that host edge states at interfaces between domains with different disorder parameters. >> 

Gui-Geng Liu, Yihao Yang, et al. Topological Anderson Insulator in Disordered Photonic Crystals. Phys. Rev. Lett. 125, 133603. Sep 24, 2020.





sabato 19 dicembre 2020

# gst: structured amorphous with enforced fragmentation

<< Many substances with different chemical and physical properties, from diamonds to graphite, are made up of carbon atoms. Amorphous forms of solid carbon do not have a fixed crystal structure and consist of structural units—nanosized graphene particles. >>

(AA) << studied the structure of amorphous carbon and suggested classifying it as a separate type of amorphous solid bodies: a molecular amorphic with enforced fragmentation. (..) sp2 amorphous carbon is a fractal structure based on nanosized graphene domains that are surrounded by atoms of other elements (hydrogen, oxygen, nitrogen, sulfur, and so on). >> 

<< The discovery and experimental confirmation of the graphene nature of the 'black gold' will completely change the theory, modeling, and interpretation of experiments with this class of substances. However, some questions remain unanswered. What does solid-state physics make of this amorphous state of solid carbon? What role does amorphous carbon with sp2-hybridization play in the bigger picture?  >>  Elena Sheka.

Physicists describe a new type of amorphous solid bodies. RUDN University. Dec 03, 2020. 


E. F. Sheka ,Ye. A. Golubev, N. A. Popova. Amorphous state of sp2 solid carbon. Fullerenes, Nanotubes and Carbon Nanostructures. doi: 10.1080/ 1536383X.2020.1815713. Sep 03, 2020.


Also 

word 'allotropy' in Cambridge Dictionary




sabato 12 dicembre 2020

# gst: apropos of poetry, poetry inside science ... and vice versa

<< Poetry is a great tool for interrogating and questioning the world,  (..) There are so many amazing science stories out there that people don't know about because they are hidden in the jargon of scientific papers, (..) Poetry levels hierarchies of intellect, >> Sam Illingworth

<< A good science poem is one that calls upon a scientific idea but then tweaks it and elevates it in a way that a simple description can’t, >> Sunayana Bhargava

Katherine Wright. Scientists Take on Poetry. Physics 13, 150. Sep 22, 2020. 


Also

Notes (quasi-stochastic poetry)






sabato 5 dicembre 2020

# brain: the drug ISRIB reverses age-related cognitive decline within days (in mice) and even enhance cognition in healthy animals

<< Just a few doses of an experimental drug can reverse age-related declines in memory and mental flexibility in mice, (..)  The drug, called ISRIB (ISR InhiBitor), has already been shown in laboratory studies to restore memory function months after traumatic brain injury (TBI), reverse cognitive impairments in Down Syndrome , prevent noise-related hearing loss, fight certain types of prostate cancer , and even enhance cognition in healthy animals. >>

<< In the new study, researchers showed rapid restoration of youthful cognitive abilities in aged mice, accompanied by a rejuvenation of brain and immune cells that could help explain improvements in brain function. >>

<< ISRIB's extremely rapid effects show for the first time that a significant component of age-related cognitive losses may be caused by a kind of reversible physiological "blockage" rather than more permanent degradation, >> Susanna Rosi.

<< The data suggest that the aged brain has not permanently lost essential cognitive capacities, as was commonly assumed, but rather that these cognitive resources are still there but have been somehow blocked, trapped by a vicious cycle of cellular stress, (..)  Our work with ISRIB demonstrates a way to break that cycle and restore cognitive abilities that had become walled off over time. >> Peter Walter.

Drug reverses age-related cognitive decline within days. University of California, San Francisco. Dec 01, 2020.


Karen Krukowski, Amber Nolan, et al. 
Small molecule cognitive enhancer reverses age-related memory decline in mice. eLife. doi: 10.7554/ eLife.62048. Dec 1, 2020.