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venerdì 1 settembre 2017

# music: harmonic resonances from moons and rings of Saturn

<< Wherever there is resonance there is music, and no other place in the solar system is more packed with resonances than Saturn >>. Matt Russo

<< Saturn's magnificent rings act like a sounding board that launches waves at locations that harmonize with the planet's many moons, and some pairs of moons are themselves locked in resonances >>. Dan Tamayo

Astrophysicists convert moons and rings of Saturn into music. Aug 30, 2017

https://m.phys.org/news/2017-08-astrophysicists-moons-saturn-music.html

giovedì 31 agosto 2017

# evol: about dino's status symbol

<< The thick body armour on some dinosaurs seems perfectly engineered to foil hungry predators. But the remains of a newly discovered armoured dinosaur hint that its spiky suit had another role: showing off to potential mates and rivals >>

<< Borealopelta lived around 110 million years ago >>

Traci Watson. Dinosaurs' spiky armour may have been status symbol. Soft-tissue patterns on a well-preserved fossil suggest that elaborate spines helped dinosaurs to attract mates and communicate. Nature doi:10.1038/nature.2017.22511 Aug 26, 2017

http://www.nature.com/news/dinosaurs-spiky-armour-may-have-been-status-symbol-1.22511

mercoledì 30 agosto 2017

# brain: to consider neurons driven by a shot noise

<< Individual presynaptic spikes can have a significant effect on a neuron's dynamics. It is thus desirable to explicitly account for the pulse-like nature of neural input, i.e. consider neurons driven by a shot noise >>

Droste F, Lindner B. Exact analytical results for integrate-and-fire neurons driven by excitatory shot noise. J Comput Neurosci. 2017 Aug;43(1):81-91. doi: 10.1007/s10827-017-0649-5. Epub 2017 Jun 6.

https://www.ncbi.nlm.nih.gov/m/pubmed/28585050/

martedì 29 agosto 2017

# gst: something that is called "non-stationarity"

<< “We’re looking at historical data when really we have something that is called non-stationarity,” Dr. Knight [Sandra Knight, a senior research engineer at the University of Maryland and a former official at the Federal Emergency Management Agency] said. “The world isn’t stationary anymore and the hydrology isn’t. The landscape isn’t. So why are we still presuming the future will look like the past?”

Nadja Popovich, Claire O'Neill. A ‘500-Year Flood’ Could Happen Again Sooner Than You Think. Here’s Why. Aug. 28, 2017

https://www.nytimes.com/interactive/2017/08/28/climate/500-year-flood-hurricane-harvey-houston.html

lunedì 28 agosto 2017

# astro: the binary black hole spin distribution, a sort of cosmic estension of Mr. Jelly Roll

<< The direct detection of gravitational waves from merging binary black holes opens up a window into the environments in which binary black holes form. One signature of such environments is the angular distribution of the black hole spins >>

AA << report that, if the magnitudes of the black hole spins are allowed to extend to high values, the effective spins for these systems indicate a 0.015 odds ratio against an aligned angular distribution compared to an isotropic one [isotropic spin orientation: the spins of the black holes are randomly oriented with respect to the orbit of the binary system]. When considering the effect of ten additional detections, this odds ratio decreases to 2.9 × 10−7 against alignment >>

Will M. Farr, Simon Stevenson, et al. Distinguishing spin-aligned and isotropic black hole populations with gravitational waves. Nature 548, 426–429 Aug 24, 2017 doi: 10.1038/nature23453

http://www.nature.com/nature/journal/v548/n7668/full/nature23453.html

https://arxiv.org/abs/1706.01385

<< Amico, qualunque  cosa suonerai . . . suonerai Jelly Roll >>

Jelly Roll Morton (opp. Mouton, alias di Ferdinand La Menthe, opp. La Mothe, New Orleans, 20 ott ~1885 - Los Angeles, 10 luglio 1941, ~56a).  Ref: Alan Lomax. "Mister Jelly Roll". Duell, Sloan & Pearce, New York (1950);  cit. in: Arrigo Polillo, "JAZZ". Oscar Saggi Mondadori. (1977):315,325.

http://inkpi.blogspot.it/search?q=jelly+roll

domenica 27 agosto 2017

# cvd: oops! so (maybe) high levels of hdl cho (high-density lipoprotein cholesterol) don't seem so good ...

<< Men and women in the general population with extreme high HDL cholesterol paradoxically have high all-cause mortality. These findings need confirmation in other studies >>

Madsen CM, Varbo A, Nordestgaard BG.  Extreme high high-density lipoprotein cholesterol is paradoxically associated with high mortality in men and women: two prospective cohort studies. Eur Heart J. Apr 12, 2017. doi: 10.1093/eurheartj/ehx163.

https://www.ncbi.nlm.nih.gov/pubmed/28419274

Philip J. Barter, Kerry-Anne Rye; HDL cholesterol concentration or HDL function: which matters? European Heart Journal, Volume 38, Issue 32, 21 August 2017, Pages 2487–2489, https://doi.org/10.1093/eurheartj/ehx274

https://academic.oup.com/eurheartj/article-abstract/38/32/2487/3835607/HDL-cholesterol-concentration-or-HDL-function

High levels of 'good' cholesterol linked to excessive mortality. Aug 23, 2017

https://www.sciencedaily.com/releases/2017/08/170823094124.htm

more

("high-density lipoprotein cholesterol"[ALL] OR "HDL-lipoprotein cholesterol"[ALL]) AND "mortality"[ALL]

https://www.ncbi.nlm.nih.gov/pubmed/?term=((%22high-density+lipoprotein+cholesterol%22%5BALL%5D+OR+%22HDL-lipoprotein+cholesterol%22%5BALL%5D))+AND+(%22mortality%22+%5BALL%5D)

sabato 26 agosto 2017

# gst: modeling around the edge of a crack

<< It is said that a weak link determines the strength of the entire chain. Likewise, defects or small cracks in a solid material may ultimately determine the strength of that material – how well it will withstand various forces >>

<< What, exactly, happens right around the edge of the crack, in the area in which those large stresses are concentrated? >>

The Breaking Point. What happens at the moving edge of crack? Aug 23, 2017

https://wis-wander.weizmann.ac.il/chemistry/breaking-point

https://www.sciencedaily.com/releases/2017/08/170823094054.htm

AA << show that cracks undergo an oscillatory instability controlled by small-scale, near crack-tip, elastic nonlinearity. This instability occurs above an ultrahigh critical velocity and features an intrinsic wavelength proportional to the ratio of the fracture energy to the elastic modulus (..) This ratio emerges as a fundamental scaling length assumed to play no role in the classical theory of cracks, but shown here to strongly influence crack dynamics >>

Chih-Hung Chen, Eran Bouchbinder & Alain Karma. Instability in dynamic fracture and the failure of the classical theory of cracks. Nature Physics doi: 10.1038/nphys4237 Publ. Aug 21, 2017

https://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys4237.html