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I stumbled upon a very interesting channel for engineers on YouTube called Lesics. It has a lot of fascinating content. Start, for instance, with a 15-minute video about the engineering details of constructing the Golden Gate Bridge. It was built in 1937 under the supervision of Joseph Strauss. You will quickly realize that the projects you are working on are trivial and insignificant compared to the challenges faced in the early 20th century. Constructing a bridge weighing nearly a million tons in a way that it could withstand load challenges unimaginable at that time is comparable to building spacecraft today. I’ve attached the link to the video in the comments.

I continue reading Ed Yong’s book Immense World about how animals interpret signals from the surrounding world. Very interesting stuff about seals.

What I learned. Seals are known for their ability to use their extremely sensitive whiskers to precisely follow the hydrodynamic trail left by their prey. To us, it looks like this: a fish swims through a complex curve, then a minute later a seal appears and follows the same curve (although a straight line might have been shorter to the fish). Research has shown that a seal can track a swimming herring from up to 180 meters away — which is comparable to dolphins’ echolocation system.

How do they manage this?

In one experiment, a complex curve was “drawn” in the water along a pool, and then seals were released, and they moved along this curve, although to our eyes, and indeed anyone’s, there was nothing left of it. This is despite the fact that the ocean water is constantly moving. The swimming fish leaves what is called a hydrodynamic trail – water vortices that last for some time (minutes), and the seals’ whiskers detect them.

It should be mentioned that seals have so-so vision, plus the water is significantly opaque (when we talk about a hundred meters) in their habitats, plus this experiment was also conducted with the vision of the seals being blocked (I don’t know how to translate blindfolded better). Vision is generally mediocre both underwater and above water for almost everyone. Birds, then humans, various felines, and a few others are exceptions.

But vortex flows are also created by the whiskers themselves — how do seals distinguish those created by the fish? It turns out that seal whiskers have a wavy structure, thickening and thinning in certain areas, which helps suppress the excitement caused by the vortex flows of the seal itself and the whiskers, and against this background, enhance the vortex flows from fish that swam in that place earlier. Ultimately, this feature increases the sensitivity of the whiskers to the hydrodynamic trails left by prey, allowing seals to hunt effectively even in conditions of poor visibility. And this is unique to seals. For instance, walruses and sea lions have simpler whiskers, and they are not as good at tracking hydrodynamic trails.

By the way, there is something similar in all fish — an organ called the lateral line. It looks like a thin line on both sides of the body, stretching from the gill slits to the base of the tail. When you are cutting up a fish, take notice, it’s quite noticeable in many of them. Lateral line organs help fish navigate, sense the direction and speed of currents, as well as detect prey or enemies, and of course, to swim synchronously in a school without bumping into each other. The sensitivity there is far from the aforementioned in seals, of course, but it is claimed that some fish can thus detect the disturbance from an insect on the surface.

Also interesting, catfish have a unique ability to perceive taste with their entire body – they essentially have taste buds located all over their surfaces from head to tail.

By the way, if a fish in an aquarium is looking at you, it appears as “fish sideways” and not “fish nose at me”. Most likely, a typical fish sees almost nothing directly in front of itself, and the area of maximum clarity is to the left or right side. So if you imagine that it is examining you, then stand by its side.

Well, I hope this was interesting. I don’t understand how some can read, I quote, “600 books a year”. When do they think? When do they stop and google? Sigh.

Should I craft a little house for him… Meanwhile, the cat is posing

The day started with Yuka waking me up with his paw and clearly showing that we need to go downstairs. We go down, he rushes to the window, and outside — snow, everything is white. Look, master — it’s winter! He barely let me have breakfast, insisted on going for a walk.

After a walk, I let him out into the yard to run around. He behaves kind of like in this video, only outdoors. Somehow, I go out and see the gate is open (unclear why – the latch is torn off, but it was always “hanging by a thread”, and it’s on the outside of the gate, not inside). And Yuki is gone. I rush to put on my sneakers, open the door on the other side of the house — he runs back home by himself. Very strange. Usually, he would just bolt toward the horizon, but apparently, his training has overcome him this time, and squirrels or other dogs were not in sight.

In short, he came home, and he’s still in the mood like in the video 🙂 When he really wants to play, we have our own language that somehow works for him, so I’m there growling in the background. Generally, he sometimes goes wild (quite rarely though).

I continue to read Ed Yong’s book “An Immense World”.

He writes about the emerald jewel wasp. This wasp—a beautiful creature about an inch long with a metallic green body and orange thighs—is a parasite that raises its young on cockroaches. When the female Ampulex compressa finds a cockroach (which is twice her size), she stings it twice: first in the middle of the body to temporarily paralyze its legs, and a second time in the brain. The second sting targets two specific groups of neurons and delivers a venom that deprives the cockroach of the desire to move on its own, turning it into an obedient zombie. In such a state, the wasp can lead the cockroach to its lair by the antennae, much like a person leads a dog. There, she lays an egg on it, providing her future larva with a compliant source of fresh meat.

This act of mind control depends on the second “sting,” which the wasp must deliver precisely to the right spot in the brain. There’s almost no brain there, and what is there is hidden somewhere among a tangle of muscles and internal organs. How does she manage?

Fortunately for the wasp, its stinger is not only a drill, venom injector, and egg-laying tube, but also a sensory organ. Its tip is covered with small bumps and indentations, sensitive to both smell and touch. With their help, she can detect the cockroach’s brain. When Gal and Libersat removed a cockroach’s brain before offering it to the wasp, she tried to find the organ, but in vain. If the brain was replaced with something of the same consistency, then the wasp found the brain, but then got confused. Thus, it can distinguish the brain from everything else with its “nose.”

Another interesting story is about the red knots, shorebirds. There are many such birds on the ocean, they probe the sand along the shore with their beaks in search of buried treasures—worms, mollusks, and crustaceans. Under the microscope, the tips of their beaks are pitted like corncobs from which all the kernels have been eaten. These pits are filled with mechanoreceptors, similar to those on our skin, particularly on our palms and fingers, and allow the birds to detect buried prey by touch.

But how does a shorebird know where to insert its beak first? Underground prey is not visible from the surface, so one might assume that the birds simply dig randomly and hope for the best.

However, in 1995, Dutch scientist Theunis Piersma showed that the birds find mollusks eight times more often than one would expect if they were searching randomly. They must have some technique. To figure it out, Piersma trained birds to inspect buckets filled with sand for buried objects and report if they found anything by approaching a specially equipped feeder. This simple experiment showed that the birds could detect mollusks buried even deeper than they can reach with their beaks. During the process, it turned out they were able to sense stones, so they clearly did not rely on smells, sounds, tastes, vibrations, heat, or electric fields.

Piersma suggested that these birds use a special form of touch that works at a distance. When a red knot’s beak plunges into wet sand, it “pushes” fine jets of water between the grains, creating a wave of pressure that radiates outward from that spot. If there is any solid object in the path (like a mollusk or a stone), the water has to flow around it, distorting the pressure pattern. The pits at the beak tip of the knot are tuned to sense these distortions. Moreover, the bird “collects” data from its radar from different points, allowing it to make fewer attempts than if it acted by unscientific probing.

It’s clear that this is a hypothesis, but one backed by experiments making it quite plausible. Because nothing else can explain the observations.

Ed also writes something interesting about the touch sensation in star-nosed moles. These are eyeless animals with a large red star on their nose. This star-shaped growth is the most sensitive tactile system known to contemporary science. Biologists have counted more than 100,000 nerve fibers in it: this is five times more than in a human hand, which is also considered to have very high sensitivity. And these 100,000 are packed into their organ, smaller than a fingertip. The sensory receptors are known as “Eimer’s organs,” named after the scientist who first observed them. They help the mole detect seismic vibrations from the environment.

Thanks to the vast number of sensory receptors, the star-nosed mole is able to find an object, determine whether it’s edible or not, and then eat it (if it’s an insect or worm) in less than 120-150 ms. That’s about the time it takes for us to blink. In this time, by merely touching what can be a worm, they understand it’s edible, and manage to “chew” it before we finish blinking. As a result, the star-nosed mole can touch and check up to 13 different small objects per second. Data exchange occurs fantastically quickly: the brain makes a decision in 8 milliseconds, which is the theoretical speed limit of neurons.

The sense of smell is also unusual. It is usually believed that mammals cannot smell underwater. Well, this creature can. To do this, moles use a unique technology. Chasing prey in swampy areas, they blow bubbles into the water, then inhale them back through their nostrils. Meanwhile, the direction of their movement correlates with the movement of the prey.

I’m reading now that vampire bats, which feed on blood, synthesize a substance that prevents this blood from clotting, making it easier to drink. What did scientists name this substance?

Correct, draculin! 😉

Today, during a conversation with my mother, the word “cybernetics” came up, and I realized that I don’t know what it is. Turns out, I indeed don’t know. I think 99% of you don’t know either.

It turns out, cybernetics is a field of science about systems, studying systems with circular cause-and-effect connections, whose outputs are also inputs, like feedback systems, and these systems can be anything – from living organisms to computer programs, as well as ecological, technological, biological, cognitive, and social systems, and also in the context of practical activities, such as design, education, and management. Overall, like any definition, it’s somewhat vague, but essentially clear.

One of the most well-known definitions belongs to the American mathematician Norbert Wiener, one of the founders of cybernetics and artificial intelligence theory. He characterized cybernetics as the science concerned with “control and communication in animals and machines.”

According to the Ozhegov dictionary, “Cybernetics is the science of the general laws of control processes and information transmission in machines, living organisms, and society.”

Another early definition emerged at the Macy conferences on cybernetics, where this science was understood as the study of “circular causality and feedback in biological and social systems,” which actually became the definition for Wikipedia. American anthropologist Margaret Mead emphasized the role of cybernetics as “a form of interdisciplinary thinking that allowed representatives from many disciplines to easily communicate with each other in a language understandable to all.” Another definition is offered by the American mathematician Lewis Kaufman: “Cybernetics is the study of systems and processes that interact with themselves and reproduce themselves.”

In general, they made it even more confusing.

By the way, the word κυβερνητικός is quite ancient, and the word cyber/кибер never related to robots. κυβερνητικός indicated the art of a helmsman, who must steer in response to the ship’s behavior – that is, to use negative feedback. Later, it was used metaphorically to denote the art of a statesman governing a city. In this sense, it is notably used by Plato in “Laws.”

The ancient Romans adapted this word to “governor,” which initially also denoted the helmsman on a ship, and then its meaning expanded to “ruler.”

This was further picked up by André-Marie Ampère, who essentially introduced it into scientific use. Ampère’s cybernetics is the science of how to govern society, people. The aforementioned Norbert Wiener then extended it to machines, while leaving scope for its use anywhere.

The illustration shows how Generative AI sees cybernetics. It’s either a diver who hanged himself or a new robot from Boston Dynamics.

There is a podcast studio called “Either-Or”. They create really good and informative channels (many of them). Currently, I’m listening to the latest episode about typhus and lice on the channel “Why Are We Still Alive”.

Among other things, it discusses how Weigl was manufacturing vaccines for typhus.

We remember that a vaccine is a weakened or killed pathogen, or its fragments, which are introduced into the body of a healthy person, so that their immune system can later cope with the same pathogen, but alive and aggressive. Vaccines are simply grown in laboratories, but the bacteria of typhus did not want to grow in tubes and Petri dishes. Moreover, of all living organisms, they chose only humans and lice, which fed exclusively on humans. Thus, making them infect laboratory animals was almost an impossible task.

What did Rudolf Weigl do? He fed lice. The process looked like this: special small wooden boxes with a mesh bottom, which allowed the louse’s proboscis to pass through but not the louse itself, were tied to a person’s thigh. The boxes were attached several at a time to a leg using elastic bandages. Sitting in these boxes, the insects sucked blood. Afterwards, the box was detached. Then the insects were killed with a five percent acid solution, the spirochetes were extracted from them, washed, and a culture of killed bacteria was obtained to create a vaccine by this method. It took processing 80 to 120 lice per person. The vaccine was needed on an industrial scale, therefore thousands of volunteers were required. Lice were fed by the whole elite of Lviv intelligentsia: there were mathematicians Stefan Banach and Vladislav Orli, geomorphologist Alfred Yan, botanist Serin Geneva, and in the future, the great Polish poet Zbigniew Herbert. All of them were called feeders, meaning providers. Each fed about 25,000 lice a month. The work, of course, was somewhat unpleasant. Despite the increased portions of bread and beetroot jam, the feeders suffered from anemia en masse. But it was definitely better than being shot on the spot or being in a concentration camp.

Besides, Weigl collaborated with the Polish underground. For instance, the poet Zbigniew Herbert was a member of the Polish military organization called the Home Army, which staged sabotages against the Wehrmacht troops. Also, the Home Army helped to smuggle surplus vaccines into the Lviv and Warsaw ghettos. The Germans wanted to exterminate the Jews with typhus, but the epidemic in the ghettos stopped as if by itself.

In 1944, when the Red Army again approached Lemberg, the city became part of the Ukrainian SSR. Weigl left there for Krakow in Poland, where he headed the typhus research institute. He continued to study the disease and teach in Poland, which became a country in the Eastern Bloc, i.e., under the control of the Soviet Union.

It’s also interesting how lice transmit typhus to humans.

…

It turns out that the Rickettsia microbe is found in the intestine of the louse, but how does it get into the human? For example, the malarial plasmodium is contained in the saliva of a mosquito and enters the blood during a bite. That makes sense. But how about with lice? The thing is, lice, while feeding on blood, leave excrement. The parasite ends up on the human skin near the bite. The spot itches, and the person begins to scratch it intensively, literally rubbing the infected feces into microabrasions. Rickettsiae penetrate the blood vessel cells and actively multiply there.”

I recommend listening to it; they have already released several seasons of only “Why Are We Still Alive”, and in addition, there are Kolmanovsky’s podcasts and various other things.

Here’s a new long-read about something interesting.

I’ve already made several posts while reading Ed Yong’s book An Immense World: How Animal Senses Reveal the Hidden Realms Around Us. Today we’re talking about shrimp. They haven’t told me much during our occasional encounters.

A quick primer for those out of the loop. We see colors because the retina of our eye has special light-sensitive cells, namely “rods” and “cones”. “Rods” provide vision in low light conditions, such as at night, and have very high-sensitivity to light but not to color. There are 130 million of them. Cones are responsible for color sensation; there are 7 million, and their light sensitivity is 100 times less than that of rods. We have three types of cones: long (L), medium (M), and short (S). They correspond to yellow-red (570 nm), green-yellow (544 nm), and violet-blue (443 nm) colors respectively. The combination of activations of these cells is perceived by the brain as color. For instance, a combination of blue and red creates indigo, which isn’t in the rainbow. Excitation of all three yields white. Beyond the 400-700 nm range, we can’t see because our three types of cones are tuned to the three peaks (see above), and color sensitivity rapidly decreases to the left and right of them. Below 400 nm is ultraviolet, above 700 nm is infrared radiation.

There are people who see the world in black and white — monochromats. Among animals, all pinnipeds, such as seals and walruses, sharks, whales, octopuses are like this. Dogs don’t have long cones, meaning their color vision is incomplete, but saying they can’t see red is incorrect. They see it as grey only when there are absolutely no shades of yellow and blue in it, which is not the case in the real world. However, this makes red on their color wheel equivalent to green.

Moreover, all primates are dichromats. Only humans have evolved vision similar to the vision of birds. But birds are even more advanced – they are tetrachromats. They have cells sensitive to ultraviolet light. The ancestors of modern mammals had lenses that let through ultraviolet light and had a photoreceptor sensitive to soft ultraviolet light. However, in some primates, particularly in humans, the lens evolved to block photons shorter than 400 nm, rendering this receptor obsolete.

So, it turns out that there’s a woman currently living in the United Kingdom with a genetic disorder, making her a tetrachromat. She sees the world with an additional color dimension — ultraviolet. Interestingly, Claude Monet, presumably after cataract surgery, perceived ultraviolet. I specifically looked for his paintings from this period in Chicago, but didn’t find any. He was old and had poor vision overall. He painted lilies abundantly during that period, it seems. By the way, for tetrachromats, the concept of “white” is different — it requires full ultraviolet presence. Without it, white looks different to them.

Apparently, this is precisely a dimension, not just an “expanded rainbow”. That is, imagine a color wheel and mentally draw an axis perpendicular to it for the saturation of ultraviolet from “none” to “a lot”. In other words, if indigo is a mix of red and blue, there is another color which we’ll call rurple, that represents indigo with ultraviolet. And this color can have different saturations.

And now, the most interesting part. There’s a kind of shrimp — mantis shrimp. It has the fastest strike in nature — an acceleration of 10,000 Gs. When hunting, its limbs develop speed up to 80-100 kilometers an hour, which is 50 times faster than the blink of a human eye, and comparable to the impact force of a .22 caliber bullet fired from a gun. The force of the strike is about one and a half thousand newtons, enough to break the hard shells of mollusks. The speed of the strike causes the formation of cavitation bubbles. When these bubbles implode, they release a large amount of heat, temporarily raising the temperature to very high levels and further weakening the armor of its prey. It was found that their “claws” consist of the mineral hydroxyapatite, and the impact part consists of nanoparticles that absorb and disperse the energy of high-magnitude impacts. Nanometer-sized spherical particles are arranged in a “Christmas-tree” pattern into a continuous sequence, similar to fish scales, which allows the impact force to be evenly distributed over the surface.

So, about those shrimp eyes, they have the most unusual eyes in the world. There, they have 12 different types of cones from ultraviolet to infrared, with four just for UV. Interestingly, their brain uses these differently: they cannot distinguish colors closer than 12-25 nm, while humans with three types of cones can distinguish a difference of 4 nm. Likely, these shrimp have “digital” color vision – red shades aren’t very important to them, and there’s simply one receptor for red. And it operates in a crude yes-no fashion. But that’s just because their brains haven’t fully developed yet. When shrimp take over the world, they will fully utilize their hardware.

They have three pseudopupils. These organs are stacked one over the other. They also have tens of thousands of clusters of photoreceptor neurons. We, for example, have just one cluster. The cells form ommatidia, making the eyes of mantis shrimp similar in structure to the compound eyes of flies.

By the way, you know that we actually see only a small circle in front of us due to the structure of the eye. The entire “world” is completed by the brain and the system of micro-movements of the eye (socalled saccades), moving this circle left, right, up, and assembling the picture into a whole. In other words, we don’t see simultaneously to the left and right. Actually, milliseconds pass between “snapshots” (from tens to hundreds).

Beyond that, shrimp eyes move independently, and there are mechanisms to determine distance with one eye. But the most mind-blowing thing is their ability not just to see the polarization of color, which is already unique, but to perceive, for example, circular polarization. First, what is polarization? Light is an electromagnetic wave. If you move a rope tied to a doorknob up and down, the plane in which that rope moves is polarization. Ordinary sunlight is unpolarized, meaning its waves vibrate in all possible directions perpendicular to the direction of propagation. However, when sunlight is reflected from surfaces like water, glass, or wet roads, it can become partially polarized. This is what polaroid sunglasses filter out, helping the driver. That’s why they also darken, because only part of the light, polarized in a certain direction, passes through. So, shrimp have the ability to see polarization as a “separate color”. This is for planar polarization. There’s also circular polarization — this is when the direction of oscillation rotates in a circle. Ultimately, it looks like a spiral or spring, where the wave moves forward, but its oscillations rotate around this direction. Shrimp can separate this type of polarization too. Moreover, they have coloring that, for shrimp that understand circular polarization, offers a richer visual picture.

It’s some kind of obscure shrimp that might not have caught our attention, but essentially, it’s like an alien. If you really look at the ocean’s inhabitants, you can find anything at all. I think real aliens will be less surprising.

Ivan Vladimirov. “Peasants Returning After the Devastation of a Manor House in the Vicinity of Pskov.” 1919.