# life: an anti-flood approach, techno- humans ask beavers for help

<< The National Trust has announced plans to release Eurasian beavers at two sites in the south of England next spring to help with flood management and to improve biodiversity. >>

National Trust announces first beaver reintroductions. Press Release. Nov 20, 2019. 

https://www.nationaltrust.org.uk/press-release/national-trust-announces-first-beaver-reintroductions

Beavers brought in to beat flooding in Britain. Nov 20, 2019.

https://m.phys.org/news/2019-11-beavers-brought-britain.html

Also

Facing a cross-border crimes. FonT.   May 9, 2017. 

https://flashontrack.blogspot.com/2017/05/n-soc-facing-cross-border-crimes.html

# brain: the flexible mental maps of flies

<< In the Drosophila brain, 'compass'  neurons track the orientation of the body and head (the fly’s heading) during navigation >>

<<  a visual cue can evoke synaptic inhibition in compass neurons and that R (ring) neurons mediate this inhibition. Each compass neuron is inhibited only by specific visual cue positions, indicating that many potential connections from R neurons onto compass neurons are actually weak or silent. (..) the pattern of visually evoked inhibition can reorganize over minutes as the fly explores an altered virtual-reality environment. >>

Yvette E. Fisher, Jenny Lu, et al. Sensorimotor experience remaps visual input to a heading-direction network.  Nature. doi: 10.1038/s41586-019-1772-4. Nov 20, 2019. 

https://www.nature.com/articles/s41586-019-1772-4

To navigate, flies make flexible mental maps of the world. Howard Hughes Medical Institute. Nov 20, 2019.

https://m.phys.org/news/2019-11-flies-flexible-mental-world.html

Also

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

https://inkpi.blogspot.com/2006/10/2066-voli-casaccio.html

# gst: measuring biological noise of gene expression

<< Essential genes are often expressed with high variability during the development of cells. Scientists call this phenomenon "biological noise" and suspect that it is also decisive for the fate of cells, i.e. the developmental pathway a cell takes. Max Planck researcher Dominic Grun now presents a method based on single-cell data to quantify this variability in gene expression.  >>

Dominic Grun << hopes to gain a better understanding of the extent to which noise regulates development or is even necessary for the differentiation of cells. >>

How gene expression noise shapes cell fate. Max Planck Society. Nov 18, 2019. 

https://m.phys.org/news/2019-11-gene-noise-cell-fate.html   

Grun D. Revealing dynamics of gene expression variability in cell state space. Nat Methods (2019) doi:10.1038/s41592-019-0632-3. Nov 18, 2019.

https://www.nature.com/articles/s41592-019-0632-3

Also

keyword 'noise' in Notes:

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

keyword 'noise' in FonT:

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

# gst: interface mobility enhances the bounce effect of bubbles

<< Theoretically, when a bubble reaches the surface of a pure liquid, the thin film of liquid between the bubble and the air above should quickly drain away, allowing the bubble to coalesce with the air. The same would be expected when two bubbles meet within the liquid or when two droplets of oil come together in water.  >>

<< Counterintuitively, bubbles or droplets reaching the highly mobile fluorocarbon liquid-air interface bounced off of the interface much more strongly than from the immobilized interface. The reason is that there is less friction on the mobile interface and thus less energy is lost during the bounce. "To our knowledge, our studies and simulations are the first to demonstrate an enhanced bounce effect due to interface mobility," >> Ivan U. Vakarelski.

When bubbles bounce back.  King Abdullah University of Science and Technology. Nov 13, 2019.

https://m.phys.org/news/2019-11-when-bubbles-bounce-back.html

Ivan U. Vakarelski, Fan Yang, et al. 

Mobile-surface bubbles and droplets coalesce faster but bounce stronger. Science Advances  25 Oct 2019:

Vol. 5, no. 10, eaaw4292 DOI: 10.1126/sciadv.aaw4292 

https://advances.sciencemag.org/content/5/10/eaaw4292

# gst: marginally outer trapped surfaces (during a binary Black Hole merger)

<< do MOTSs (marginally outer trapped surfaces, or marginal surfaces) merge in a BBH (binary black hole ) coalescence, and if so, how, exactly? >>

<< It is an underappreciated fact that event horizons are not really very useful for studying astrophysical properties of black hole mergers, (..) What is much more useful are surfaces which go under the boring name of marginally outer trapped surfaces (..). This uninteresting name hides their importance in understanding black holes. >>

Ingrid Fadelli. Numerical evidence for the merger of MOTSs inside a binary black hole. Nov 1, 2019

https://m.phys.org/news/2019-11-numerical-evidence-merger-motss-binary.html

Daniel Pook-Kolb, Ofek Birnholtz, et al. 

Interior of a Binary Black Hole Merger. Phys. Rev. Lett. 123, 171102 Oct 21, 2019. 

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.123.171102

# gst: apropos of turbulences close to a wall, the repetitive structure of a vortex

<< At the boundary where a fluid flows over a fixed structure, a turbulent boundary layer is created where the fluid interacts with the wall, creating eddies in the current. These eddies may seem to be random on first glance, but they actually create distinct patterns, with countless tiny eddies close to the wall; fewer but larger eddies located a little farther out; and even fewer, but still larger, eddies beyond those. >>

<< "We knew that, underlying these very complicated structures, there had to be a very simple pattern. We just didn't know what that pattern was until now," says McKeon, who next plans to dig deeper into the model to quantify just how many eddies should be included to create an accurate representation of the whole. >>

Engineers exploit the repeating structure of turbulence to create a more complete model of the phenomenon. California Institute of Technology. Nov 6, 2019.

https://m.phys.org/news/2019-11-exploit-turbulence-phenomenon.html

Beverley J. McKeon. Self-similar hierarchies and attached eddies. Phys. Rev. Fluids 4, 082601(R). Aug 26, 2019.

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.4.082601

# gst: multiple singularities by optical vortices (a 30y review)

<< Vortices are common phenomena that widely exist in nature, from quantum vortices in liquid nitrogen to ocean circulation and typhoon vortices and even spiral galaxies in the Milky Way. Vortices also exist in optics, the concept of which was first proposed by theoretical physicist Pierre Coullet and colleagues [Opt. Commun. 73, 403 (1989)] thirty years ago. Hitherto, owing to their amazing structures, optical vortices have engendered tremendous advanced applications such as optical tweezers, quantum entanglement, and nonlinear optics, throughout every branch of modern optics. >>

Commemorating 30 years of optical vortices: A comprehensive review. 

Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences. Nov 4, 2019.

https://m.phys.org/news/2019-11-commemorating-years-optical-vortices-comprehensive.html

Yijie Shen, Xuejiao Wang, et al. Optical vortices 30 years on: OAM manipulation from topological charge to multiple singularities. Light: Science & Applications volume 8, Article number: 90. Oct 2, 2019.

https://www.nature.com/articles/s41377-019-0194-2