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Excerpts from the Red Folder.


If we had a “Physics paper title of the year award”, the 2020 winner would surely have to be “The arches of chaos in the solar system”, which was published this week in Science Advances by Nataša Todorović, Di Wu and Aaron Rosengren. In their paper, the trio “reveal a notable and hitherto undetected ornamental structure of manifolds, connected in a series of arches that spread from the asteroid belt to Uranus and beyond”. These manifolds are structures that arise from the gravitational interactions between the Sun and planets. They play an important role in spacecraft navigation and also explain the erratic nature of comets.

The paper is beautifully written, describing the manifolds as “a true celestial autobahn,” and going on to say that they “enable ‘Le Petit Prince’ grand tour of the solar system”. And if that has not piqued your curiosity, the figures are wonderful as well – with the above image being “Jovian-minimum-distance maps for the Greek and Trojan orbital configurations”.

The luxury watchmaker Bremont has released the Hawking Limited Edition watch that contains bits of a wooden desk once used by the late Stephen Hawking. The “exquisite chromometer” also contains pieces of a meteorite and is etched with a view of the night sky as seen from Oxford on 8 January 1942, Hawking’s place and date of birth. What is more, the serial number of the watch is printed on paper from a 1979 paper by Hawking that was cowritten by Gary Gibbons.

With fall and winter holidays coming up, many will be pondering the relationship between food and sleep. Researchers led by Professor Masashi Yanagisawa at the University of Tsukuba in Japan hope they can focus people on the important middlemen in the equation: bacterial microbes in the gut. Their detailed study in mice revealed the extent to which bacteria can change the environment and contents of the intestines, which ultimately impacts behaviors like sleep.

The experiment itself was fairly simple. The researchers gave a group of a powerful cocktail of antibiotics for four weeks, which depleted them of intestinal microorganisms. Then, they compared intestinal contents between these mice and control mice who had the same diet. Digestion breaks food down into bits and pieces called metabolites. The research team found significant differences between metabolites in the microbiota-depleted mice and the control mice. As Professor Yanagisawa explains, “we found more than 200 differences between mouse groups. About 60 normal metabolites were missing in the microbiota-depleted mice, and the others differed in the amount, some more and some less than in the control mice.”

The team next set out to determine what these metabolites normally do. Using metabolome set enrichment analysis, they found that the biological pathways most affected by the antibiotic treatment were those involved in making neurotransmitters, the molecules that cells in the brain use to communicate with each other. For example, the tryptophan–serotonin pathway was almost totally shut down; the microbiota-depleted mice had more tryptophan than controls, but almost zero serotonin. This shows that without important gut microbes, the mice could not make any serotonin from the tryptophan they were eating. The team also found that the mice were deficient in vitamin B6 metabolites, which accelerate production of the neurotransmitters serotonin and dopamine.

A material that mimics human skin in strength, stretchability and sensitivity could be used to collect biological data in real time. Electronic skin, or e-skin, may play an important role in next-generation prosthetics, personalized medicine, soft robotics and artificial intelligence.

“The ideal e-skin will mimic the many natural functions of human skin, such as sensing temperature and touch, accurately and in real time,” says KAUST postdoc Yichen Cai. However, making suitably flexible electronics that can perform such delicate tasks while also enduring the bumps and scrapes of everyday life is challenging, and each material involved must be carefully engineered.

Most e-skins are made by layering an active nanomaterial (the sensor) on a stretchy surface that attaches to human skin. However, the connection between these layers is often too weak, which reduces the durability and sensitivity of the material; alternatively, if it is too strong, flexibility becomes limited, making it more likely to crack and break the circuit.

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They say age breeds wisdom. But can we grow personally and mature, while staying young and healthy? Can ageing be cured just like any other disease? We asked David Sinclair, professor of genetics at Harvard Medical School.

David Andrew Sinclair is an Australian biologist and Professor of Genetics best known for his research on the biology of lifespan extension and driving research towards treating diseases of aging.

Artificial intelligence is being applied to virtually every aspect of our work and recreational lives. From determining calculations for the construction of towering skyscrapers to designing and building cruise ships the size of football fields, AI is increasingly playing a key role in the most massive projects.

But sometimes, all we want to do is move a can of beans.

According to a recently published abstract by researchers at the University of California, Berkeley, they have developed a mechanism that “couples a perception pipeline predicting a target occupancy support distribution with a mechanical search policy that sequentially selects occluding objects to push to the side to reveal the target as efficiently as possible.”

Throughout all known space, between the stars and the galaxies, an extremely faint glow suffuses, a relic left over from the dawn of the Universe. This is the cosmic microwave background (CMB), the first light that could travel through the Universe when it cooled enough around 380,000 years after the Big Bang for ions and electrons to combine into atoms.

But now scientists have discovered something peculiar about the CMB. A new measurement technique has revealed hints of a twist in the light — something that could be a sign of a violation of parity symmetry, hinting at physics outside the Standard Model.

According to the Standard Model of physics, if we were to flip the Universe as though it were a mirror reflection of itself, the laws of physics should hold firm. Subatomic interactions should occur in exactly the same way in the mirror as they do in the real Universe. This is called parity symmetry.

Researchers have recently displayed the interaction of superconducting qubits; the basic unit of quantum information, with surface acoustic wave resonators; a surface-wave equivalent of the crystal resonator, in quantum physics. This phenomena opens a new field of research, defined as quantum acoustodynamics to allow the development of new types of quantum devices. The main challenge in this venture is to manufacture acoustic resonators in the gigahertz range. In a new report now published on Nature Communications Physics, Aleksey N. Bolgar and a team of physicists in Artificial Quantum Systems and Physics, in Russia and the U.K., detailed the structure of a significantly simplified hybrid acoustodynamic device by replacing an acoustic resonator with a phononic crystal or acoustic metamaterial.

The crystal contained narrow metallic stripes on a quartz surface and this artificial atom or metal object in turn interacted with a microwave transmission line. In engineering, a transmission line is a connector that transmits energy from one point to another. The scientists used the setup to couple two degrees of freedom of different nature, i.e. acoustic and electromagnetic, with a single quantum object. Using a scattering spectrum of propagating electromagnetic waves on the they visualized acoustic modes of the phononic crystal. The geometry of the device allowed them to realize the effects of quantum acoustics on a simple and compact system.