When someone claims that everyone knows something, either they are short-cutting and specifically mean ‘everyone in this well-defined small group where complex common knowledge of this particular thing is something we have invested in,’ they are very wrong about how the world works, or much more commonly, they are flat out lying. Saying that everybody knows is almost never a mistake. The statement isn’t sloppy reasoning. It’s a strategy that aims to cut off discussion or objection, to justify fraud and deception, and to establish truth without evidence.
Month: August 2021
Rural change
Increasing farm productivity has been the dominant force shaping rural America over the past 150 years. Improving transportation has offset some of the population decline (and its ill effects) by improving access to jobs and services, especially near cities. Improved communications, increasing acceptance of remote work, and new transportation options are poised to turn every rural community into a bedroom community for cities, providing more income opportunities. Physical transportation systems like VTOL taxis, electric airplanes, and HyperLoops take things to the next level by providing access to in-person city jobs and services. As the cost of animal protein declines, farming and ranching will see shifts. High-density grazing can increase the productivity of grasslands, reducing the demand for feed from cropland. It also produces healthier cows that need less finishing in feedlots to taste good. Further farm consolidation and conversion of cropland to grazing land seem likely. The impact will vary widely by location. In Georgia, where cotton is the dominant crop, and Atlanta is a powerhouse city, negatives will be few and far between. High plains land that benefits from improved grazing techniques could flourish. In an isolated river valley in Iowa with land ideally suited for industrial production of corn and soybeans, things might not be so pleasant for big farms. Life could improve for the median resident that has more income earning options. The worst-case scenario is that demand for traditional animal products falls while improvement in work options ends up being limited. The worst-case scenario seems much less likely with StarLink coming online and COVID-19 normalizing remote work. While farm operations will probably consolidate, the average land parcel size could decline as every rural community becomes a bedroom community. Small plots could proliferate. If farming and grazing acreage declines, negative environmental impacts could result. In previously forested places, a return makes sense. But in the high plains, residents may have to organize roaming ruminant herds or prescribed burns to maintain their prairie and prevent desertification. Things rarely change very fast in rural communities, but the coming decades could be a lot more fun and pleasant than the past 15.
Thermodynamic Clocks
an ideal clock — one that ticks with perfect periodicity — would burn an infinite amount of energy and produce infinite entropy, which isn’t possible. Thus, the accuracy of clocks is fundamentally limited. “What we’ve done is to show that even if time is a perfect, classical and smooth parameter governing time evolution of quantum systems, we would only be able to track its passage” imperfectly, through stochastic, irreversible processes. “Could it be that time is an illusion and smooth time is an emergent consequence of us trying to put events into a smooth order? It is certainly an intriguing possibility that is not easily dismissed.”
Hycean Worlds
Hycean worlds are hot mini-Neptunes with hydrogen-rich atmospheres and vast oceans on their surfaces. The heat and the pressure wouldn’t be very inviting to us humans, but it’s possible that some forms of life might find it idyllic. these worlds can be up to 2.6x the width of Earth, up to 10 Earth masses, and temperatures in their atmospheres could reach 200 °C. However, conditions in their oceans might be more comfortable. They’re likely to be common too, nestled in between the smaller, rockier Super-Earths and the gaseous, larger mini-Neptunes. Hycean planets could be one of the most promising places to look for signs of life. Not only because they’re common, but biomarkers of life, such as methyl chloride and dimethyl sulphide, could be readily spotted in their atmospheres
Roman Food Dimorphism
By measuring the isotopes of carbon and nitrogen in the bone amino acids, researchers were able to reconstruct the diets of people who lived contemporaneously in much more detail than was previously thought possible. “We found significant differences in the proportions of marine and terrestrial foods consumed between males and females, implying that access to food was differentiated according to gender.” Males were more likely to be directly engaged in fishing and maritime activities, they generally occupied more privileged positions in society, and were freed from slavery at an earlier age providing greater access to expensive commodities, such as fresh fish.
Hypergraphs
The higher-order analogue of a graph is called a hypergraph, and instead of edges, it has “hyperedges.” Purvine and her colleagues analyzed a database of biological responses to viral infections, using hypergraphs to identify the most critical genes involved. They also showed how those interactions would have been missed by the usual pairwise analysis afforded by graph theory. However, generalizing from graphs to hypergraphs quickly gets complicated. There are lots of ways of generalizing this notion of a cut to a hypergraph. But there’s no one clear solution, because a hyperedge could be severed various ways, creating new groups of nodes.
2023-04-13: Another powerful concept only very vaguely related are Hypervectors (though this Github project seems to allow you to play with both)
Hyperdimensional computing promises a new world in which computing is efficient and robust, and machine-made decisions are entirely transparent.
Hyperdimensional computing tolerates errors better, because even if a hypervector suffers significant numbers of random bit flips, it is still close to the original vector. Another advantage of hyperdimensional computing is transparency: The algebra clearly tells you why the system chose the answer it did. The same is not true for traditional neural networks. It’s also compatible with “in-memory computing systems,” which perform the computing on the same hardware that stores data (unlike existing von Neumann computers that inefficiently shuttle data between memory and the central processing unit). Some of these new devices can be analog, operating at very low voltages, making them energy-efficient but also prone to random noise. For von Neumann computing, this randomness is “the wall that you can’t go beyond”. But with hyperdimensional computing, “you can just punch through it.”
Potassium Pools
Potassium ions are vital for the functioning of all living cells. The transfer of potassium ions across nerve cell membranes is necessary for normal nerve transmission; potassium deficiency and excess can each result in numerous signs and symptoms, including an abnormal heart rhythm and various electrocardiographic abnormalities. Fresh fruits and vegetables are good dietary sources of potassium. The body responds to the influx of dietary potassium, which raises serum potassium levels, with a shift of potassium from outside to inside cells and an increase in potassium excretion by the kidneys.
Phanerozoic Temperature
By combining global temperature estimates from geological data with estimates of tropical temperatures obtained from oxygen isotope studies, it is possible to produce an estimate of the global average temperature for any time in the past. The modern global average temperature is 14.5˚C. The average global temperature for the last 540 ga is 20˚C, but the temperature has fluctuated between 25˚C (hothouse) and 10˚C (icehouse). During the Permo-Triassic Extinction, the global temperature spiked above 28˚C. Most of the time, the global temperature gently rises and falls in response to gradual changes in orbital and solar parameters, ocean currents, sea level, atmospheric chemistry (greenhouse gases), and other factors. These changes occur over millions of years. Rarely, there is a drastic change in one of these factors resulting in either rapid global warming (Kidder–Worsley events) or rapid global cooling (Stoll-Schrag events). These abrupt climate excursions take place over 1000s of years, rather than millions of years.
the world was colder than today only 2% of the time in the last 540 ga.
Turing Patterns
Turing’s paper described a theoretical mechanism based on 2 substances — an activator and an inhibitor that diffuse across an area at different rates. The interaction between these 2 “morphogens,” as Turing called them, allows one to interrupt the effect of the other — creating a pattern of colored lines on a tropical fish, for example, rather than a solid color. Turing’s mechanism was indeed responsible for the stripes in the bismuth. And it demonstrated once again how robust and powerful Turing’s original insight was. Here, the stripe-forming process is driven by the forces at play among the bismuth atoms and the metal below. Bismuth atoms want to fit into particular spots on the molecular lattice of the metal. But these spots are closer together than the bismuth atoms find comfortable. Like a photograph that gets shoved into a frame that’s too small for it, the sheet of bismuth atoms buckles. The strain creates a wavy pattern that leaves some atoms raised, forming the stripes. The vertical shift — movement away from the plane of the crystal — acts as the activator in the Turing equations, while the shift within the plane acts as the inhibitor. The morphogens here are displacements, not molecules. When part of a Turing pattern is wiped out, it grows back. You might not assume that inorganic materials like bismuth crystals would be able to heal as animals do,but indeed, his team’s simulated bismuth crystal was able to mend itself.
Animal Numerosity
Practically every animal that scientists have studied — insects and cephalopods, amphibians and reptiles, birds and mammals — can distinguish between different numbers of objects in a set or sounds in a sequence. They don’t just have a sense of “greater than” or “less than,” but an approximate sense of quantity: that 2 is distinct from 3, that 15 is distinct from 20. This mental representation of set size, called numerosity, seems to be “a general ability,” and an ancient one. Many species have displayed a capacity for abstraction that extends to performing simple arithmetic, while a select few have even demonstrated a grasp of the quantitative concept of 0 — an idea so paradoxical that very young children sometimes struggle with it. Both monkeys and honeybees know how to treat 0 as a numerosity, placing it on a mental number line much as they would numerosity 1 or 2. And crows can do it, too.
Gregor J. Rothfuss 