perestroika

In the article, researchers modeled the passage of the solar system through the galactic interstellar medium, components of which move at differing velocities and orbits.

They found that approximately 2-3 megayears ago, the solar system most likely entered a cloud of mainly cold hydrogen, and the density of the cloud was such that it should have considerably compressed the heliosphere (Sun's bubble of radiation and fields). Earth would have been outside the heliosphere either permanently or periodically. Currently the heliosphere ends far beyond the most distant planet, at approximately 130 Earth-Sun distances (astronomical units).

This would have greatly subdued the influence of solar wind on Earth, at the same time exposing the planet to interstellar cosmic rays. It is further speculated that studies which analyze Earth climate during the aforementioned period may benefit from accounting for this possibility.

Researchers sought confirmation for their model from geological records and found some, in the isotope content of iron and plutonium in sediments: iron 60 and plutonium 244 aren't produced by processes on Earth, so an influx would mean that solar wind no longer sufficed to beat back interstellar gas and dust (the latter containing radioisotopes from supernova explosions).

"By studying geological radioisotopes on Earth, we can learn about the past of the heliosphere. 60Fe is predominantly produced in supernova explosions and becomes trapped in interstellar dust grains. 60Fe has a half-life of 2.6 Myr, and 244Pu has a half-life of 80.7 Myr. 60Fe is not naturally produced on Earth, and so its presence is an indicator of supernova explosions within the last few (~10) million years. 244Pu is produced through the r-process that is thought to occur in neutron star mergers22. Evidence for the deposition of extraterrestrial 60Fe onto Earth has been found in deep-sea sediments and ferromanganese crusts between 1.7 and 3.2 Ma (refs. 23,24,25,26,27), in Antarctic snow [28] and in lunar samples [29]. The abundances were derived from new high-precision accelerator mass spectrometry measurements. The 244Pu/60Fe influx ratios are similar at ~2 Ma, and there is evidence of a second peak at ~7 Ma (refs. 23,24)."

Some Chinese researchers have found a new catalyst for electrochemically reducing CO2. Multiple such catalysts are known, but so far, only copper favours reaction products with a carbon chain of at least 2 carbons (e.g. ethanol).

The new catalyst requires a specific arrangement of tin atoms on tin disulphate substrate, seems to work in a solution of potassium hydrogen carbonate (read: low temperature) and is 80% specific to producing ethanol - a very practical chemical feedstock and fuel.

The new catalyst seems stable enough (97% activity after 100 hours). Reaction rates that I can interpret into "good" or "bad" aren't found - it could be slow to work. The original is paywalled, a more detailed article can be found at:

Carbon-Carbon Coupling on a Metal Non-metal Catalytic Pair

Overall, it's nice to see some research into breaking down CO2 for energy storage, but there is nothing practical (industrial) on that front yet, only lab work.

To my knowledge, this is the second time a sample is returned from an asteroid to Earth - only preceded by Hayabusa-2 fetching a sample from asteroid Ryugu. The capsule has been found and the sample stabilized with nitrogen. Fetching the sample required 7 years, studying it will require a bit of time too.

It is too early to speculate whether interesting discoveries will follow, but Bennu is considered to be an interesting asteroid - likely not a break-up product, but something that represents the original composition of the solar system.

Bennu is also considered a hazardous space object, ranked high on the Palermo scale of impact risk and kinetic yield, so knowing what it's made of can be practically worthwhile.

More information here:

https://en.wikipedia.org/wiki/OSIRIS-REx

The inverse vaccine, described in Nature Biomedical Engineering, takes advantage of how the liver naturally marks molecules from broken-down cells with “do not attack” flags to prevent autoimmune reactions to cells that die by natural processes.

PME researchers coupled an antigen — a molecule being attacked by the immune system— with a molecule resembling a fragment of an aged cell that the liver would recognize as friend, rather than foe. The team showed how the vaccine could successfully stop the autoimmune reaction associated with a multiple-sclerosis-like disease.

Most people would typically think than smelling a scent (unless it's a powerful poison or medicament) won't change much in a person's health... but apparently, a variation in the scent environment has effect on the human brain, especially if the person is already old and their senses are degrading. It has also been observed that viral infections damaging a person's olfactory nerves result in changes to the brain - with less input, the neural networks involved with scent tend to atrophy. Coinidentally, some neural networks involved with scent recognition are also involved with memory.

Prios studies already support the idea that training one's sense of smell helps older people avoid cognitive deterioration. This study brings highly significant statistical results and adds one bit - wakefulness is not required to benefit. Apparently, the stimulation a person receives from feeling different scents bypasses sleep (or maybe, even improves the quality of sleep).

Long story made short: apparently, the previous administration didn't really try (since it was Bolsonaro's, I am not surprised). EU import controls and financial interventions have also helped:

He believes the slowdown is due to a combination of factors: the resumption of embargoes and other protection activities by the government, improved technical analysis that reveal where problems are occurring more quickly and in more detail, greater involvement by banks to deny credit to landowners involved in clearing trees, and also wariness among farmers generated by the European Union’s new laws on deforestation-free trade. It may be no coincidence that deforestation has not fallen as impressively in the cerrado savanna, which is not yet covered by the EU’s controls.

Superconductivity is a condition of matter where resistance to electrical current disappears.

The first superconductors needed cooling to near the absolute zero. The next generation worked at temperatures of liquid nitrogen. A room-temperature atmospheric-pressure superconductor is a highly sought after material (e.g. it would expand possibilities to hande plasma for fusion research and make MRI machines easier to build).

A substance named LK-99 has recently caused interest in the research community. Its a copper-enriched lead apatite, typically made by reacting lead sulphate with copper phosphide. It is speculated to be superconductive at room temperature.

It is also thought that interesting properties are not inherent to the substance, but a particular kind of crystal lattice which this subtance obtains - if produced in certain ways.

The name LK-99 refers to Sukbae Lee and Ji-Hoon Kim, and the number refers to 1999, when these Korean researchers first stumbled upon it.

Studies back then were interrupted. They weren't certain of its properties and it was hard to make repeatably. When a researcher named Tong-Shik Choi died in 2017, he requested in his will that research into LK-99 be continued. The resources were found and his request was granted.

Then, other factors intervened, among them COVID. The first article was rejected by Nature because an extraordinary claim requires extraordinary proof. An article in Arxiv (not peer reviewed) at the end of July 2023 drew international attention, however.

Many persons and teams started attempting to replicate the experimental results. The process is still half way through, but considerable progress has been made.

• Beijing University, school of material science + Beihang university: the experiment was made, but the effect could not be reproduced (they obtained a paramagnetic semiconductor of little interest)

• Huazhong University, center for crystalline materials and micro/nanodevices: they obtained a diamagnetic crystal with interesting properties (repelled by a ferromagnet regardless of orientation, a property which a superconductor must have, but which is also shared by non-superconductive diamagnets)

• National Physics Laboratory of India: failed to replicate the effect

• Professor Sun Yue, South-Eastern University of China: got a weak diamagnetic crystal

• Iris Alexandra (from Russia, plant physiologist): with an alternative production method, obtained a tiny but strongly diamagnetic crystal

• Sinéad Griffin (Lawrence Berkley National Laboratory, from the US): published an article, attempting to theoretically explain how superconductivity might arise in the substance, explanatory tweet here

• Junwen Lai (Shenyang National Material Science Laboratory, China): published an article about the electron structure of the substance, without opinion regarding superconductivity, with the opinion that gold doping would be better than copper doping

So, strong evidence is absent until now - we may have much merriness about nothing. There is a bunch of hypothesis and enough material to fit on a fingertip. :)

Background:

https://en.wikipedia.org/wiki/LK-99