# bot: 3D-printed micro-bristle-bot, vibrobot (expected everywhere ...)

<< A bristle-bot or vibrobot is a multi-legged robot made of bristles and an oscillating actuator that generates vibrations. This work presents the first demonstration of a micro-bristle-bot, with 3D-printed legs, fabricated by two-photon polymerization lithography. The presented miniaturized bristle-bot has a weight of only 5 mg, in the size of 2 mm × 1.87 mm × 0.8 mm, and can achieve a speed up to 4 times the body length per second.  >>

<< The presented micro-bristle-bots show a resonant frequency around 6.3 kHz, which can be tailored based on their geometry. This feature allows for addressing individual micro-bristle-bots with various geometries based on their unique resonance frequency. >>

DeaGyu Kim, Zhijian Hao, et al. A 5mg micro-bristle-bot fabricated by two-photon lithography. Journal of Micromechanics and Microengineering. Jul 9, 2019.

https://iopscience.iop.org/article/10.1088/1361-6439/ab309b  

John Toon. Tiny vibration-powered robots the size of the world's smallest ant. Georgia Institute of Technology. Jul 17, 2019.

https://m.techxplore.com/news/2019-07-tiny-vibration-powered-robots-size-world.html  

# phys: synchronizing nano 'Pendulums'

AA << report synchronization of the mechanical dynamics of a pair of optomechanical crystal cavities that, (..) are intercoupled with a mechanical link and support independent optical modes. In this regime they oscillate in antiphase, >>

AA << also show how to temporarily disable synchronization of the coupled system >>

Colombano MF, Arregui G, et al. Synchronization of Optomechanical Nanobeams by Mechanical Interaction. Phys. Rev. Lett. 123, 017402. July 1, 2019.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.123.017402  

Katherine Wright. Synopsis: Synchronizing Nanosized "Pendulums". Jul 1, 2019.

https://physics.aps.org/synopsis-for/10.1103/PhysRevLett.123.017402 

# gst: a floating vortex of fluff, the flight of the dandelion

<< A fluff-topped dandelion seed can float through the air for more than a kilometer before it drifts to the ground. In experiments last year, researchers revealed that the white filaments in the fluff-known collectively as a pappus-create a ring-shaped wake behind the seed that is associated with low pressure and acts to keep it aloft. >>

AA << have theoretically modeled the airflow around the pappus, reproducing the experimentally measured wake and showing that it provides the seed with steady flight capabilities. >>

Katherine Wright. Dandelion Fluff Perfected for Flight. July 2, 2019

https://physics.aps.org/synopsis-for/10.1103/PhysRevFluids.4.071901

Ledda PG, Siconolfi L, et al. Flow dynamics of a dandelion pappus: A linear stability approach. Phys. Rev. Fluids 4, 071901(R) July 2, 2019.

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.4.071901

# game: inside an irregular 'rock-paper-scissors' game; 'uneveness nomads' will survive, probably ...

AA << study a class of the stochastic May-Leonard models, with three species dominating each other in a cyclic nonhierarchical way, according to the rock-paper-scissors game. (They) introduce an unevenness in the system, by considering that one of the species is weaker because of a lower selection probability. >>

To << investigate the coexistence probability (..) the surviving species depends on the level of unevenness of the model and the mobility of individuals. >>

Menezes J., Moura B., Pereira TA. Uneven rock-paper-scissors models: Patterns and coexistence. EPL -  Europhysics Letters, Volume 126, Number 1. May 22, 2019.

https://iopscience.iop.org/article/10.1209/0295-5075/126/18003/meta   

Lisa Zyga. The rock-paper-scissors game and coexistence. Phys.org.
Jul 4, 2019

https://m.phys.org/news/2019-07-rock-paper-scissors-game-coexistence.html   

# acad: apropos of pulsating, nomadic entities; to generate and manage 'theories and vagrant thoughts', by Isaac

<< Presumably, the process of creativity, whatever it is, is essentially the same in all its branches and varieties, so that the evolution of a new art form, a new gadget, a new scientific principle, all involve common factors. We are most interested in the “creation” of a new scientific principle or a new application of an old one, but we can be general here. >>

Isaac Asimov Asks, "How Do People Get New Ideas?". A 1959 Essay by Isaac Asimov on Creativity. Oct 20, 2014.

https://www.technologyreview.com/s/531911/isaac-asimov-asks-how-do-people-get-new-ideas/amp/

https://twitter.com/techreview/status/1147256914016964608

# phys: optical vortex to probe magnetism in matter

<< A light "corkscrew" is sensitive to the local magnetic field direction, so it can be used to probe magnetism in a material. >>

<< Circularly polarized light can act as a powerful probe of magnetism in matter. By measuring differences in the transmission of light beams polarized in different directions as they pass through a material, physicists can unravel atomic-level details of the material’s magnetic properties. >>

Synopsis: Optical Vortices Can Probe Magnetism. Jun 12, 2019.

https://physics.aps.org/synopsis-for/10.1103/PhysRevLett.122.237401

A. A. Sirenko, P. Marsik, et al. Terahertz Vortex Beam as a Spectroscopic Probe of Magnetic Excitations. Phys. Rev. Lett. 122, 237401. Jun 12, 2019.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.122.237401

# brain: short-term exercise enhances brain function

<< Exercise is cheap, and you don't necessarily need a fancy gym membership or have to run 10 miles a day, >> Gary Westbrook

AA << designed a study in mice that specifically measured the brain's response to single bouts of exercise in otherwise sedentary mice that were placed for short periods on running wheels. The mice ran a few kilometers in two hours. >>

<< short-term bursts of exercise- the human equivalent of a weekly game of pickup basketball, or 4,000 steps- promoted an increase in synapses in the hippocampus. Scientists made the key discovery by analyzing genes that were increased in single neurons activated during exercise. >>

<< One particular gene stood out: Mtss1L. This gene had been largely ignored in prior studies in the brain. >>

Study reveals a short bout of exercise enhances brain function. Oregon Health & Science University.  Jul 3, 2019.

https://m.medicalxpress.com/news/2019-07-reveals-short-bout-brain-function.html   

AA << results link short-term effects of exercise to activity-dependent expression of Mtss1L, which propose as a novel effector of activity- dependent rearrangement of synapses. >>

Christina Chatzi, Yingyu Zhang, et al.  Exercise-induced enhancement of synaptic function triggered by the inverse BAR protein, Mtss1L.  eLife 2019; 8: e45920. doi: 10.7554/eLife.45920. Jun 24, 2019

https://elifesciences.org/articles/45920