Month: March 2022

Trigger Waves

Biomechanical interactions, rather than neurons, control the movements of one of the simplest animals. The discovery offers a glimpse into how animal behavior worked before neurons evolved.

We show a minimal mechanism — trigger waves — by which these walking cells may work together to achieve organism-scale collaboration, such as coordination of hunting strikes across 100k cells without central control.

The behavior of Trichoplax can be described entirely in the language of physics and dynamical systems. Mechanical interactions that began at the level of a single cilium, and then multiplied over millions of cells and extended to higher levels of structure, fully explained the coordinated locomotion of the entire animal. The organism doesn’t “choose” what to do. Instead, the horde of individual cilia simply moves — and the animal as a whole performs as though it is being directed by a nervous system. The cilia’s dynamics exhibit properties that are commonly seen as distinctive hallmarks of neurons.

2022-03-30: Physical gradients

Much of the research to date on self-generated gradients has looked at chemical signals, but cells can create gradients in other physical attributes, too, including mechanical properties. The recent paper analyzing migrating neural crest cells revealed a self-generated gradient of stiffness.

2022-07-13: Embryogenesis involves the extracellular matrix contracting

Mechanical forces induce embryonic chicken skin to create follicles for growing feathers. Just as surface tension can pull water into spherical beads on a glass surface, so too can the physical tensions within an embryo set up patterns that guide growth and gene activity in developing tissues. As an organism grows and develops, the cells in its tissues pull and push on each other and on the supportive protein scaffolding (extracellular matrix) to which they are intricately linked. Some researchers have suspected that these forces, coupled with changes in the pressure and rigidity of the cells, might direct the formation of complicated patterns. Until now, however, no studies were able to tease apart the effect of these physical forces from the chemical stew in which they simmer.

Reuse Design

Aluminum panels are marked by grade and the car is designed for disassembly; at the end of its life, technicians can easily sort the materials for recycling by specific type, rather than melting different aluminum grades together and compromising the material. The company is doing away with the standard practice of bonding unlike materials in the interior. When you glue a veneer to a plastic, then glue metal trim around the edges of it, you’ve rendered all 3 materials unrecoverable. In contrast, Missoni and his team have designed all of the soft-touch interior elements to be monomaterial, made of “a highly recyclable thermoplastic.” These interior elements “can be recycled as one material, and not only that, they can be recycled over and over again.”

Ukraine

Collecting a few pointers to how this might play out in the longer term. It seems clear that this will accelerate the move away from petro-kleptocracies towards renewable energy as a national security matter.

Europe can stop buying Russian gas. Russia might have trouble selling it because you can’t build new pipelines overnight. Russian oil will find a home somewhere else by boat, rail, or truck. It turns out a ban isn’t necessary anyway. Oil and natural gas supply and demand curves are inelastic. Small changes in supply or demand move prices dramatically. It costs money to produce oil and gas. Reducing the price by 40% might reduce profits by 80%-90%. And a 2%-3% demand decrease might be enough to do the trick. Focus on lowering the profits. Oil is a global market in a way natural gas is not. Europe has to do the heavy lifting for natural gas. There are many economical options available, especially for substitution. Increasing oil and gas supply requires massive changes in the law for European countries. Europe has to keep investing in new gas supply and reducing demand to prevent future price spikes. Eventually, new technologies that create synthetic gas or shift industrial processes to electricity will pick up the slack. Maybe even a few nuclear power plants will get built.

The optimal end to this war is for Russian leadership — generals, spymasters, oligarchs, and politicians — to simply remove Vladimir Putin from power, form a new government, and withdraw Russian troops from Ukraine. The whole war can be blamed on Putin, and Russia and the West can quickly go back to having good relations.

The current sanctions give them a number of incentives to do this. The fall in the ruble, the crashing of the Russian economy, the cutoff of economic relations with the West, and sanctions against Putin-allied individuals all mean that the globetrotting comfy lifestyle Russian leaders have gotten used to over the past two decades is no longer available. If the war ends, these sanctions will presumably be reversed, and something like the old normal can be restored.

And this needs to be made explicit. EU leaders and Biden need to announce clearly and repeatedly that if Russian troops pull back from Ukraine, the sanctions will all be quickly dropped. The part about removing Putin from power doesn’t need to be stated; it will be implicit.

But in fact, the EU and US need to promise Russia much more than this. The reason is that all the stuff I described in the last section — the long-term replacement of Russia’s economic lifeblood with renewable energy — is going to happen anyway, war or no war. The threat of climate change, and the rapid progress in solar, wind, and storage technology, mean that the world’s days of dependence on oil and gas are numbered. Russia is in big long-term trouble no matter what it does.

This gives the EU and US an additional lever — the promise of a Marshall Plan to help the Russian economy retool. Dropping sanctions will restore Russian oil and gas revenue in the short term, but in the long term Russia needs things like infrastructure investment, FDI in manufacturing industries, trade agreements to facilitate European and American purchases of Russian-made goods, and so on. The EU and the US can provide all this. We can make numerical guarantees and specify sectors — railroads, roads, aerospace, IT, whatever.

Hadean Oceans

Oceans formed far more quickly than expected:

The Hadean eon, following the global-scale melting of the mantle, is expected to be a dynamic period, during which Earth experienced vastly different conditions. Geologic records, however, suggest that the surface environment of Earth was already similar to the present by the middle of the Hadean. Under what conditions a harsh surface environment could turn into a habitable one remains uncertain. Here we show that a hydrated mantle with small-scale chemical heterogeneity, created as a result of magma ocean solidification, is the key to ocean formation, the onset of plate tectonics and the rapid removal of greenhouse gases, which are all essential to create a habitable environment on terrestrial planets. When the mantle is wet and dominated by high-magnesium pyroxenites, the removal of carbon dioxide from the atmosphere is expected to be more than ten times faster than the case of a pyrolytic homogeneous mantle and could be completed within 160 ma. Such a chemically heterogeneous mantle would also produce oceanic crust rich in olivine, which is reactive with ocean water and promotes serpentinization. Therefore, conditions similar to the Lost City hydrothermal field may have existed globally in the Hadean seafloor.