Tuesday, February 28, 2023

Foraging for Behavior Patterns and Other Levy Things


Read a disappointing book recently called The Drunkard's Walk -- only disappointed because I thought it would be about the drunkard's walk but it was just about randomness in statistics and probability. Thought it would be about Levy flights, foraging behavior, random walks, saccades, etc. Something very fractal about the nature of these phenomena.


Explore or exploit: How our brains make choices
Apr 2022, phys.org

Basically, newer areas of the brain (evolutionarily speaking) such as the lateral prefrontal cortex, activated more when an unfamiliar choice was made while older brain systems including the amygdala and the orbitofrontal cortex showed increased activation while weighing the value of explorations vs. exploitation. This suggests that both the newer and older circuits in the brain worked together during the decision-making process rather than against each other as was previously thought.

via University of New Mexico: Jeremy Hogeveen et al, The neurocomputational bases of explore-exploit decision-making, Neuron (2022). DOI: 10.1016/j.neuron.2022.03.014


Typical movement behavior at large events increases risk of spreading infectious diseases
Sep 2022, phys.org

Burstiness (another word for foraging pattern behavior)

An earlier paper on this topic compared the movements of individuals in the crowd to the typical foraging patterns that were also present in our human hunter-gatherer ancestors.

The first author of the study, Ph.D. candidate Philip Rutten, says, "This [new study] shows that, if the infection probability is time-dependent, an intermittently moving but freely mixing crowd may present the highest level of transmission risk." 

Because infection is a probability game.

via University of Amsterdam: Philip Rutten et al, Modelling the dynamic relationship between spread of infection and observed crowd movement patterns at large scale events, Scientific Reports (2022). DOI: 10.1038/s41598-022-19081-z


Not-so private eyes: Eye movements hold clues to how we make decisions
Dec 2022, phys.org

"Unlike your arms or legs, the speed of eye movements is almost totally involuntary. It's a much more direct measurement of these unconscious processes happening in your brain."

In the study, the team asked 22 human subjects to walk on a treadmill then choose between different settings displayed on a computer screen: a brief walk up a steep grade or a longer walk on flat ground.

Researchers discovered that the subjects' eyes gave them away: Even before they made their choices, the treadmill users tended to move their eyes faster when they looked toward the options they ended up choosing. The more vigorously their eyes moved, the more they seemed to prefer their choice.

"Initially, the saccades to either option were similarly vigorous," Ahmed said. "Then, as time passed, that vigor increased and it increased even faster for the option they eventually chose."

via University of Colorado at Boulder: Colin C. Korbisch et al, Saccade vigor reflects the rise of decision variables during deliberation, Current Biology (2022). DOI: 10.1016/j.cub.2022.10.053

Image credit: A laser beam (orange) creates excitons (purple) that are trapped inside the semicondcutor material by electric fields. Credit: Puneet Murthy / ETH Zurich

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The New Digital Earth


We are on our way to creating a second Earth in the digital realm, where we can do experiments and run simulations to better understand the real Earth. It's called a digital twin, and it happens in other sectors like medicine (where we can test new drugs in a simulation of your body) or industry (where we can monitor all the variables in the manufacture of a product to find the most efficient method).

Developments in persistent satellite surveillance, vision and other sensing technologies, and climate modeling and forecasting keep getting better, and with each advance in these areas, the digital Earth twin gets closer and closer to the real Earth. 

Image credit: This Size 49 ecumonopolis was built on the video game Stellaris, around Amogus Prime.


Real-time space observations can now keep watch over 'super emitter' power plants
Oct 2022, phys.org

They use NASA's "Orbiting Carbon Observatory 2" (OCO-2; launched in 2014) and the OCO-3, attached since 2019 to the International Space Station (ISS).

"This future capacity will lead to improved CO2 emission information at the scale of countries, cities or individual facilities, enhancing transparency under the Paris Agreement and supporting efforts to reduce emissions causing climate change."

via Environment and Climate Change Canada: Tracking CO2 emission reductions from space: A case study at Europe's largest fossil fuel power plant, Frontiers in Remote Sensing (2022). DOI: 10.3389/frsen.2022.1028240


Climate simulation more realistic with artificial intelligence
Oct 2022, phys.org

A generative adversarial network made a simple climate model way better, so it can handle more complex data. 

via Technical University Munich: Philipp Hess, Physically constrained generative adversarial networks for improving precipitation fields from Earth system models, Nature Machine Intelligence (2022). DOI: 10.1038/s42256-022-00540-1


Google Earth on steroids' gives a boost to urban development
Dec 2022, phys.org

Uzufly's system uses drones to take aerial photographs, producing thousands of images that are transformed into 3D models through the creation of digital twins, or digital replicas of real-world objects. These objects could be buildings, for example, which are georeferenced down to the centimeter. The company's 3D models incorporate a wide range of urban-planning data and can accommodate any type of architectural design at full scale.

via Ecole Polytechnique Federale de Lausanne spin-off Uzufly

Image credit: AI Art - Sacred Geometry - 2023

A silicon image sensor that computes
Aug 2022, phys.org

The computer is in the eyeballs of the camera, they are one and the same:

CMOS-integrated "in-sensor processing" and programmable pixels

via Harvard John A. Paulson School of Engineering and Applied Sciences: Houk Jang et al, In-sensor optoelectronic computing using electrostatically doped silicon, Nature Electronics (2022). DOI: 10.1038/s41928-022-00819-6


Atomic-level 3D models show us how gadgets work
Oct 2022, phys.org

This can create a digital twin at the atomic level:

"Atom probe tomography" can provide a three-dimensional representation of what a material looks like, right down to the atomic level.

via Norwegian University of Science and Technology: K. A. Hunnestad et al, Atomic-scale 3D imaging of individual dopant atoms in an oxide semiconductor, Nature Communications (2022). DOI: 10.1038/s41467-022-32189-0


Wearable wristband captures entire body in 3D
Nov 2022, phys.org

The camera is on the wrist, facing the body, and with that limited information, it can infer what the entire body is doing. 

"Our research shows that we don't need our body frames to be fully within camera view for body sensing," Lim said. "If we are able to capture just a part of our bodies, that is a lot of information to infer to reconstruct the full body."

via Cornell's SciFiLab: Hyunchul Lim et al, BodyTrak, Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies (2022). DOI: 10.1145/3552312


Worldwide dataset captures Earth in finest ever detail
Nov 2022, phys.org

Metabolism of the Anthroposphere is here:
WorldStrat - 10,000km² of free satellite images with resolutions as high as 1.5m per pixel (each pixel is a 1.5m by 1.5m area on the ground), using the SPOT 6 and SPOT 7 satellites from ESA, as well as using the lower resolution Copernicus Sentinel-2 satellite.

via University College London and European Space Agency: Julien Cornebise et al, Open High-Resolution Satellite Imagery: The WorldStrat Dataset—With Application to Super-Resolution, arXiv (2022). DOI: 10.48550/arxiv.2207.06418


The Real Climate Change is Us Doing This:
Startup claims to offer stratospheric geoengineering as a service
Dec 2022, Ars Technica via MIT Tech Review

(The company is called Make Sunsets)

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Free Thermodynamic Lunch


There is a lot of extra energy lying around; you call almost call it free energy, and we are getting better at picking up all these scraps. And what are we doing with it? Making everything intelligent.

Battery-free, light-powered pacemaker may improve quality of life for heart disease patients
Oct 2022, phys.org

Wireless, battery-free pacemaker could be implanted with a less invasive procedure using a new digitally manufactured mesh design that encompasses the entire heart that works with optogenetics, which means it uses light instead of electrical signals. 

via Gutruf Lab at University of Arizona: Jokubas Ausra et al, Wireless, fully implantable cardiac stimulation and recording with on-device computation for closed-loop pacing and defibrillation, Science Advances (2022). DOI: 10.1126/sciadv.abq7469


High-performance and compact vibration energy harvester created for self-charging wearable devices
Nov 2022, phys.org

Microelectromechanical system piezoelectric vibration energy harvester that can amplify power generated from impulsive vibrations, such as from a human walking.

via  Osaka Metropolitan University: Sengsavang Aphayvong et al, Enhanced performance on piezoelectric MEMS vibration energy harvester by dynamic magnifier under impulsive force, Applied Physics Letters (2022). DOI: 10.1063/5.0116838


Harvesting big energy from small movement
Jan 2023, phys.org

It's made of alternating tiny fibers 100 times thinner than a human hair, one made of ethylene-vinyl acetate, and one of polylactic acid.

Wherever there is any movement around the layers of the fibers, electricity is generated from the friction between each layer.

"We can make around 400 times more electricity from motion than was previously possible from these materials."

via University of Melbourne: Artis Linarts et al, Electrospinning Triboelectric Laminates: A Pathway for Scaling Energy Harvesters, Small (2023). DOI: 10.1002/smll.202205563


Harvesting energy from moving trains
Jan 2023, phys.org

After several years of design review, CVeSS researchers created a new kind of tie that replaces the conventional wooden variety and is equipped to generate power. Their high-tech tie, placed underneath the rail, is topped with a heavy metal bar mounted on a spring creating electricity, which can then be stored in a battery.

"For every wheel of the train that goes by, we are harvesting 15 to 20 watts of power," said Ahmadian. "If we have a long train with maybe 200 railcars, that's 800 wheels, making 1.6 kilowatts. Once we have stored that energy, we are able to use it to make the tracks more intelligent by embedding sensors in them."

via Virginia Tech Center for Vehicle Systems and Safety and Railway Technologies Laboratory: Yu Pan et al, A half-wave electromagnetic energy-harvesting tie towards safe and intelligent rail transportation, Applied Energy (2022). DOI: 10.1016/j.apenergy.2022.118844


Device transmits radio waves with almost no power—without violating the laws of physics
Jan 2023, phys.org via The Conversation

What we showed is that a powered signal source is not needed. Instead, random thermal noise, present in all electrically conductive materials because of the heat-driven motion of electrons, can take the place of the signal driving the antenna.

It seems like it violate the second law of thermodynamics. But the resolution of this seeming paradox is that the receiver in our system is powered and acts like a refrigerator. Nearly all of the power consumption happens at a base station that does not have constraints on energy use.

via University of Washington: Zerina Kapetanovic et al, Communication by means of modulated Johnson noise, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2201337119

Image credit: Kilonova Gamma Ray Burst GRB 211211A, artist impression. Aaron M Geller, Northwestern CIERA and IT Research Computing Services. 2022

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Monday, February 27, 2023

Headlines For Me But Not For Thee


Axolotls can regenerate their brains, revealing secrets of brain evolution and regeneration
Sep 2022, phys.org

Researchers develop hierarchically self-assembled homochiral helical microtoroids
Nov 2022, phys.org

Jet lagged plants pave the way to first digital plant
Nov 2022, phys.org

Heart attack on a chip shows how heart changes after the event
Dec 2022, phys.org

Feline genetics help pinpoint first-ever domestication of cats
(Feline geneticist Leslie A. Lyons come on)
Dec 2022, phys.org


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Everybody Loves Fermions


Graphs may prove key in search for Holy Grail of quantum error correction
Oct 2022, phys.org

It was a serendipitous discovery:

Quantum information is very fragile and prone to errors. You can't check for errors in a quantum system, because the act of checking itself collapses the system.

"The noise is very strong at the quantum scale," says Chapman. "And this makes quantum error correction very difficult."

You need some redundancy that allows you to tell if something has happened without knowing the underlying information."

There are quantum error correcting codes that are known to be self-healing, but they only work in four dimensions — one more than exists in this world. [right thanks]

In the new paper, the researchers showed that some subsystem codes can be represented as a certain kind of graph. [nodes and links]

"I had a seemingly unrelated pure mathematics project studying graph spectra," says Kollár, "and we realized that the numerical scripts that I had for that project could easily be modified to compute the energy cost of errors for the kinds of codes that Adrian and his collaborators had been looking at."

via Joint Quantum Institute: Adrian Chapman et al, Free-Fermion Subsystem Codes, PRX Quantum (2022). DOI: 10.1103/PRXQuantum.3.030321

Image credit: Anatoly Fomenko

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The Revolution Will Be Fermions


Team develops graphene-based nanoelectronics platform
Dec 2022, phys.org

In metals, electric currents are carried by negatively charged electrons. But contrary to the researchers' expectations, their measurements suggested that the edge currents were not carried by electrons or by holes (a term for positive quasiparticles indicating the absence of an electron). Rather, the currents were carried by a highly unusual quasiparticle that has no charge and no energy, and yet moves without resistance. The components of the hybrid quasiparticle were observed to travel on opposite sides of the graphene's edges, despite being a single object.

The unique properties indicate that the quasiparticle might be one that physicists have been hoping to exploit for decades — the elusive Majorana fermion predicted by Italian theoretical physicist Ettore Majorana in 1937.

"Developing electronics using this new quasiparticle in seamlessly interconnected graphene networks is game changing," de Heer said.

via Georgia Institute of Technology: Vladimir S. Prudkovskiy et al, An epitaxial graphene platform for zero-energy edge state nanoelectronics, Nature Communications (2022). DOI: 10.1038/s41467-022-34369-4

Image credit: Anatoly Fomenko


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The Topological Zoo


Is it topological? A new materials database has the answer
May 2022, phys.org

Topo is coming:

Harnessing the power of multiple supercomputers to map the electronic structure of more than 96,000 natural and synthetic crystalline materials to determine whether and what kind of topological traits exist in each structure.

Overall, they found that 90 percent of all known crystalline structures contain at least one topological property, and more than 50 percent of all naturally occurring materials exhibit some sort of topological behavior.

Topological Materials Database - periodic table of topology
Inorganic Crystal Structure Database - atomic and chemical structures of crystalline materials

via MIT, Princeton and the École Normale Supérieure Paris: Maia G. Vergniory et al, All Topological Bands of All Non-Magnetic Stoichiometric Materials, Science (2022). DOI: 10.1126/science.abg9094

Image credit: Topological Zoo - Anatoly Fomenko - 1967
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Friday, February 24, 2023

Neuropsychedelia


Nicolas Langlitz is a penetrating wordsmith, a great writer, and one who can wrestle the meta better than most. (His other book is a study of the people who study primates, a meta-primatology study.)

Neuropsychedelia: The Revival of Hallucinogen Research Since the Decade of the Brain
Nicolas Langlitz, University of California Press, 2013

  • On the importance of the "principle of measured sloppiness" for experimental systems (see Rheinberger, Toward a History of Epistemic Things, Stanford, 1997) - sloppiness is what led Hofmann to "accidentally" discover LSD; he is usually meticulous in his bench work.
  • "The fact that hallucinogens make an organism more susceptible to its surroundings and the increased impressionability they induce bring about a situation in which locality and social context are strongly implicated in the findings of hallucinogen experiments." (p76) This is a good example of the meta-scientific lens, which is deployed expertly by Langlitz, especially in his book Cultural Primatology.
  • The problem with hallucinogens as medicine (and a valuable lesson for anyone interested in the burgeoning cannabis industry, both medicinal and recreational) - "From the pharmaceutical industry's point of view, the problem drugs are not the opiates or cocaine but the hallucinogens, the drugs so indelibly associated with the 1960s. The problem is not that these drugs could tell us a lot about ourselves and this knowledge might foment revolution, although these do seem to be possibilities. The problem is that with each dose every individual is likely to have a different experience. This is the very antithesis of quality as corporations currently define it. It seems difficult to see how hallucinogens can be brought into the area of standardization." (p77) Referencing The Creation of Pharmacology by David Healy in 2002. 
  • Describing participation in a psilocybin experiment: "For a moment, I felt irritated by the fact that my brain could do no better than imitate the geometric forms prevailing in psychedelic art." (p89)
  • The neuromolecular gaze - The Birth of the Neuromolecular Gaze by Abi-Rached et al in 2010
  • The neuralese dialect - "In its rejection of conventional manners of speaking and the corresponding social institutions, this radicalism, despite the different political undertones, was not so far removed from Timothy Leary's "neurological revolution," which had been propagated in an early neuralese dialect. (p205)
  • The neurochemical self - "One scientist who had just fallen in love was joking about his oxytocin level. E-mails were signed "seronteregically Yours." And after, I had given him the sociologist Nikolas Rose's (2003a) article of the same title to read, pharmacologist Felix Hasler began to speak of himself as a "neurochemical self."
  • Bioautomatons - "We're nothing but senseless bioautomatons!" (quoting Boris Quednow, p211)
  • On the Self:
Honza Samotar, Swiss physician of Czech descent who worked on 2 theses simultaneously: one on insect navigation with respect to potential applications in robotics, the other on the effects of hallucinogenic drugs on the human brain (p215) ... What distinguishes Samotar's mysticism of biology from the biology of the mystical (as investigated in neurotheological studies) is that its spiritual focal point is not the extraordinary mental states engendered by hallucinogenic drugs but rather the ordinary existence to which the self-experimenter eventually returns. (p218)

Honza Samotar: In my eyes, the mystical cannot be found in such ego dissolution experiences, which make you feel at one with everything. The truly mystical is that, when the drug effects wear off, you always return to your point of departure in everyday consciousness, to the baseline, so to speak. It's about the fact that I can lose myself in a state in which I'm not a human anymore, in which I lack both individuality and sociality, in which I have no lifetime because I'm eternal, being everything and nothing, neither dead nor alive, not divided into subject and object, not located in a universe with a beginning and an end -- and that this state eventually comes to an end, that I can even remember it. In retrospect, I then tell myself: yes, there are states in which I'm eternal, but then I'm not myself -- then it simply is, that state is. And strangely enough, I always come back here, to the same body at the same place. That's what I conceive of as mystical. (p219)

Image credit: AI Art - Neuropsychedelia - 2022



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