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Beautiful white wall paint does not stay beautiful and white forever. Often, various substances from the air accumulate on its surface. This can be a desired effect because it makes the air cleaner for a while -- but over time, the color changes and needs to be renewed. Now, special titanium oxide nanoparticles have been developed that can be added to ordinary, commercially available wall paint to establish self-cleaning power: The nanoparticles are photocatalytically active, they can use sunlight not only to bind substances from the air, but also to decompose them afterwards.

AI is revolutionizing the way researchers seek to identify new materials, but it still has some shortcomings. Now, a team of researchers has navigated AI's pitfalls to identify a thermoelectric material that boasts remarkable properties.

AI is revolutionizing the way researchers seek to identify new materials, but it still has some shortcomings. Now, a team of researchers has navigated AI's pitfalls to identify a thermoelectric material that boasts remarkable properties.

A new iron-based aqueous flow battery shows promise for grid energy storage applications.

Scientists made a single-molecule transistor using quantum interference to control electron flow. This new design offers high on/off ratio and stability, potentially leading to smaller, faster, and more energy-efficient devices. Quantum interference also improves the transistor's sensitivity to voltage changes, further boosting its efficiency.

Scientists made a single-molecule transistor using quantum interference to control electron flow. This new design offers high on/off ratio and stability, potentially leading to smaller, faster, and more energy-efficient devices. Quantum interference also improves the transistor's sensitivity to voltage changes, further boosting its efficiency.

Conventional quantum algorithms are not feasible for solving combinatorial optimization problems (COPs) with constraints in the operation time of quantum computers. To address this issue, researchers have developed a novel algorithm called post-processing variationally scheduled quantum algorithm. The novelty of this innovative algorithm lies in the use of a post-processing technique combined with variational scheduling to achieve high-quality solutions to COPs in a short time.

Annealing processors are crucial for solving combinatorial optimization problems. However, they face scalability challenges due to the complexity of required architecture. TUS researchers have now designed a scalable, fully-coupled processor with 4096 spins and parallel processing capabilities. It demonstrates superior performance and power efficiency compared to traditional devices. The research team aims to develop a 2050-level quantum computer computing system by 2030, potentially revolutionizing digital industries without relying on extensive infrastructure or cloud support.

New work aimed to study the star-forming gas in a single radio galaxy. Although the team didn't find any star-forming gas in the galaxy they were studying, they instead discovered other galaxies while inspecting the data. In total, the gas of 49 galaxies was detected.

Biologists use a novel method of simultaneous acoustic tagging to gain insights into the link between whale communication and behavior

Models suggest summer rainfall in southern Europe could decline by up to 48% by the year 2100 if emissions of greenhouse gases continue to rise rapidly.

The author of In Ascension, the latest pick for the New Scientist Book Club, on why he wrote his novel, cultivating a sense of wonder and the role of fiction in the world today

Changes in wind patterns and desertification may be increasing the amount of dust from the Sahara desert blown over western Europe and the frequency of these events

We’ve talked before about “positionality statements” (see here and here; also Sally Satel’s article here). These are statements, usually put at the end of an academic paper, in which the authors give all kinds of information about their upbringing, ethnicity, race, sexual identity, sexual inclination, upbringing, and so on. It’s the kind of information that the Woke use when making a statement, putting it in the blank space here:  “As a _____________, I feel that. . . . ”

Here’s a typical statement, one that I’ve posted before:

I (first author) was raised as a Muslim immigrant-origin girl in a small Iowa town and constantly aware that my family was “different.” Having been an educator in PK-12 contexts, my goal in studying developmental psychology was to make the process easier for other youth who, like myself, were intersectionally minoritized and privileged because of religious, racial, ethnic, linguistic, and/or other identities or experiences. I was unprepared for the microaggressions embedded in developmental scholarship rooted in non-inclusive modes of knowledge production that resisted the nuances of the diverse individuals and groups I sought to better understand. . . . I seek to place myself in relationships and contexts to learn and engage in a co-conspiring, co-liberatory inquiry stance.

These are cringe-worthy of course, but their proponents say they’re useful.  I say they’re not, as did Sally Satel. In this matter Dorian Abbot, my heterodox colleague at the University of Chicago, also agrees. You can see his short HeterodoxSTEM article (it’s worth subscribing if you’re in STEM) by clicking the headline below.

 

The reason usually asserted for people making statements like this is that, by giving the authors’ backgrounds and beliefs, it enables the reader to better judge the paper scientifically, possibly being aware of biases that might affect a paper’s results or conclusions. But the authors should have been aware of this themselves and expunged any bias in their data collection or analysis, or at least gotten another pair of eyes to look over the paper before submitting it. And, of course, looking at the science in a paper, and seeing if it’s solid, is the job of the reviewers who decide whether it’s meritorious enough to be worth publishing. If authors can’t vet their own papers for accuracy before they submit them, they shouldn’t be doing science. As Sally Satel said:

Rather than confess the blind spots and biases they think they have, scientists should make their data transparent; pre-register research hypotheses; engage in rigorous, blind peer review; and publish detailed letters to the editor. It is the research that should come under scrutiny, not the researcher.

It seems likely to me that these statements have other purposes beyond vetting a paper. They are often used to flaunt virtue or even confess the author’s whiteness or other failings; in other words, they consitute = contrition, braggadocio, or both. The statements’ purpose is as much (or more) ideological than it is scientific. It also verges on solipsism.

As Dorian notes, the NSF prohibits such statements in proposals for getting grants:

the NSF has banned any personal information on official biosketches, for good reason (bolding is mine):

Individuals are reminded not to submit any personal information in the biographical sketch. This includes items such as: home address; home telephone, fax, or cell phone numbers; home e-mail address; driver’s license number; marital status; personal hobbies; and the like. Such personal information is not appropriate for the biographical sketch and is not relevant to the merits of the proposal.

So the NSF, for good reasons (irrelevance to the merit of a paper), prohibits these statements, but authors merrily include them when allowed, and one journal (according to Satel, it’s the Journal of Women and Minorities in Science and Engineering) even requires them!

Dorian gives an over-the-top example of such a statement that he found here. It’s in the Journal of Paleobiology, part of a three-authored article on the underrepresentation of women in that field:

Nan Crystal Arens (she/her) is a White, cisgender, heteroromantic woman and professor in the Department of Geoscience at Hobart & William Smith Colleges (HWS). She was a first-generation college student with a learning disability that significantly slows her parsing and processing written language. HWS is a predominantly White, private undergraduate institution where faculty are encouraged to engage actively in scholarship, although both time and resources for this component of faculty work are extremely limited. HWS faculty in the natural sciences boast a strong tradition of including undergraduate students in their research, as reflected here. Arens’s advocacy for greater inclusion of historically marginalized people in STEMM arises both from her experience as a woman in geology and paleontology and as the mother of two cisgender women who are just beginning to confront the inequities of the world.

“Levi Holguin (he/they) is a person assigned female at birth, neurodivergent, queer, first-generation college student, and part of an immigrant family. They come from a low-income background and are a devotee of folk Catholicism. Many of his identity markers challenge normative standards in the several communities of which he is a part. This draws them into conversations regarding gender and intersectionality. He was motivated in this work by the desire to make change that will open opportunities for marginalized people.

“Natalie Sandoval (she/her) is an undergraduate Latina attending a predominantly White, private institution as a first-generation student. She is cisgender and queer, does not live with a disability, and from a low-income immigrant family. Growing up in an immigrant Latino family, she is no stranger to forced gender roles and machismo, which draws her to gender studies and equity issues. She has done previous research on gender representation in STEMM careers and feelings of belonging on campus. Her previous research also includes family planning and contraceptive use. She is a community advocate through the National Diversity Coalition and seeks opportunities to improve gender equity, accessibility, and human rights through community advocacy and policy change.”

Heteroromantic? Queer? Not disabiled?  What are the sweating author trying to convey with that information? I can’t see anything in these statements that would make me evaluate the paper differently from how I’d do it if I lacked this information. (Do note the virtue-flaunting!).

I don’t have much to add to what I’ve said before—save that this is just one more attempt of the Ideological Camel to insinuate its carcass into the Tent of Science.  In effect, it devalues what science is presented by implying that it might be biased (and offers no help in fixing any such bias!).  Dorian has a few words at the end that echo my own sentiments:

Positionality statements are a flagrant violation of one of the key Mertonian Norms of science, universalism, which states that “scientific validity is independent of the sociopolitical status/personal attributes of its participants.” They are not just political grandstanding, which is bad enough, but actually act to undermine the ideal of the disinterested collection of evidence and development of explanatory theories by the scientific method, and therefore decrease confidence in scientific results. In science, it doesn’t matter if your father was a prince or pauper, what you look like, where you came from, or what naughty stuff you do with whom. Science is science, data are data, and bullshit is bullshit. In order to preserve the integrity of the scientific process, journals should ban positionality statements, and we, as reviewers, should automatically reject any paper that includes them.

Amen!

Japanese tits sometimes flutter their wings in an apparent gesture of encouraging their mate to enter their shared nest first

Today’s instructive photo-and-text contribution comes from reader Athayde Tonhasca Júnior and deals with a topic we’ve discuss a lot: biological sex and its consequences. In this case, we learn about how organisms adaptively adjust the sex ratio of their offspring when conditions change.

Athayde’s captions and IDs are indented, and you can enlarge the photos by clicking on them.

Sometimes snips, snails and puppy-dogs’ tails, other times sugar and spice

As the story goes, during a tour of a government farm, American First Lady Grace Coolidge was being shown around by a farmer when she saw a cockerel and a hen romantically engaged. She asked her guide how often the cockerel would mate, to which he responded: ‘dozens of times a day.’ Good-humouredly, Mrs Coolidge retorted: ‘tell that to the President’. The farmer dutifully did so, and President Calvin Coolidge asked: ‘same hen every time?’, to which the farmer replied: ‘No, Mr President, a different hen every time.’ And the president: ‘tell that to Mrs Coolidge.’

Psychology Professor Frank A. Beach (1911-1988) saw this improbable anecdote as an ideal model to name a widespread phenomenon among animals: the Coolidge Effect, which is the enhanced sexual interest of males whenever a new female is accessible, regardless of the availability of previous sexual partners – a behaviour rarely reported for females. This shocking manifestation of male chauvinism has been offered a biological explanation.

The term ‘gonochorism’ makes us scramble for the dictionary, even though one of the first things we learned from our Birds and Bees lessons – or used to learn before ideological gangrene poisoned Facts and Reality – is that our species is gonochoric (or dioecious), that is, it has two sexes: the male sex produces or is geared up to produce gametes (reproductive cells) called sperm, while the female sex is equipped to produce gametes known as ova or egg cells. The lesson’s climax was the revelation that some types of frolicking could result in the fusion of these two types of gametes to produce babies.

Male and female Mandarin ducks (Aix galericulata), a gonochoric and sexually dimorphic (sexes have different morphological characteristics) species © Francis C. Franklin, Wikimedia Commons

Later in life, when we took biology courses, we were told that many plants and some animals are hermaphrodites (they produce male and female gametes), while other organisms don’t need sex to reproduce. But the overwhelmingly majority of animals, and all mammals and birds, are sexually binary: they either produce male gametes or female gametes – leaving aside the rare cases of individuals that don’t fit in either category. And, from humans to asparagus, that is, for virtually all multicellular organisms, the female gametes are larger – often much larger – than the male gametes; that’s to say they are anisogamous: the two types differ in size and shape. And anisogamy has much to do with the Coolidge Effect.

Because sperm are relatively small, energetically cheap gametes, males can afford to churn out and distribute lots of them. By mating with as many females as possible, males increase their chances of passing on their genes. If a male gamete ends up in an unsuitable female, it’s not a big deal: there are plenty more fish in the sea. It doesn’t work like that for females. They put a lot of energy into their eggs, which are gigantic when compared to sperm. So, a female can only make a few of them in her lifetime. Adding gestation and time spent nurturing their young, females have a much lower reproductive capacity. As they invest a great deal more in producing an embryo than males, they need to choose their mates well to maximize their chances of success; if their Romeos are weak and unfit, females may have wasted all their reproductive potential. For females, it’s a matter of quality, not quantity.

Together at last. A human male sex cell (spermatozoon) penetrating a human ovum. The spermatozoon is ~100,000 times smaller than the ovum. Image in the public domain, Wikimedia Commons.

These biological particularities are strong incentives to polygyny, the mating system where a male has multiple sexual partners while the female mates with one or a few males. Polygyny is the most common mating strategy for vertebrates; about 90% of mammal species are polygynous. These males are, like the Coolidges’ rooster, always ready for a new romantic adventure.

Angus John Bateman (1919–1996), a botanist who worked with fruit flies, found one important consequence of the Coolidge Effect. For most polygynous species, a small number of males monopolize the females and prevent other males from mating. That is, some males are highly successful in reproducing, while many more have no success at all. Things are more predicable for females: most of them will mate – the few successful males will make sure of that. The upshot is that males’ reproductive success is more variable than females’.

The winner takes it all: while one red deer stag (Cervus elaphus) keeps harems of up to 20 hinds, other males go with no dates © Keven Law, Wikimedia Commons.

Enter evolutionary biologist Robert Trivers and computer scientist Dan Willard (1948-2023) to thicken the plot by proposing that differences in reproductive success can bias the production of male and female offspring. Trivers and Willard argued, reasonably, that sons and daughters of females in good condition (that is, well-fed, healthy, and not pressured by competitors) would also be in good condition, whereas sons and daughters of females in poor condition (malnourished or debilitated by parasites or competitors) would also be in bad condition. But, when the reproductive success of one sex – males, in the case of polygynous species – is more variable than the other, diverging strategies emerge. In an evolutionary sense, it pays for strong, healthy females to have many sons, who mate frequently and produce lots of grandchildren for their mother. Daughters on the other hand are a less promising investment because, despite being strong like mum, they are restricted by low reproductive rates. But if the mother is in poor condition, having daughters would be a better deal because despite being feeble like mum, those who survive to adulthood are likely to produce some offspring. Feeble sons on the other hand may never breed, as they would be no match for males in good condition (Trivers & Willard, 1973). In other words, when things get bad, it’s better to have more daughters than sons. This risk-spreading strategy is a form of biological bet-hedging to maximize fitness and applies beyond mammal polygyny. If females’ reproductive success is more variable, we should expect more sons than daughters when the going gets rough.

Representation of the Trivers-Willard hypothesis for polygynous species. Low-quality females are more successful than low-quality males, but high-quality males and more successful than high-quality females © Shyu & Caswell, 2015.

The Trivers–Willard hypothesis provides an explanation for a common occurrence among animals: sex ratios going astray. In theory, a species should produce about the same number of sons and daughters (1:1 ratio) to maintain long term stability. This is known as the Fisher’s principle – although it would be fairer to call it the ‘Cobb’s principle’ after the solicitor and amateur biologist John Cobb (1866-1920), who first proposed it (Gardner, 2023) (Cobb’s work is virtually unknown today, and academics from the Church of Woke would have conniptions at citing his paper, published in The Eugenics Review).

The Trivers–Willard hypothesis has had an enormous influence in evolutionary biology. Its predictions have been supported by studies with a range of species, although its universality has been debated and questioned. Nonetheless, the hypothesis has encouraged much theoretical and empirical research about sex allocation. This body of work has revealed that variation of reproductive success between sexes is not the only driver of sex ratio skewness. Food, mothers’ age, litter size, population density, the weather, or some other environmental or physiological factor may induce females to adjust the sex ratio of their offspring to maximise fitness.

UK’s age-sex pyramid illustrating the population’s distribution by age groups and sex. The male to female ratio is 1.05 at birth, shifting to 0.73 for those aged 65 and over © Kaj Tallungs, Wikipedia.

It turns out that food availability is an important inducer of sex ratio fine-tuning for one group of animals of enormous ecological end economic importance: cavity-nesting solitary bees. Most of the 20,000 or so known species of bee build their nests in the ground, but about 30% of them took another path regarding housing. They occupy or expand naturally occurring cavities such as crevices under or between stones, cracks in a wall, holes in dead wood, hollow stems and tree bark, transforming them into cosy, safe environments in which to raise their young.

Like all solitary bees, cavity-nesting species are on the wing for a small portion of their lives, sometimes weeks. After mating, each female spends her short adult life tirelessly victualing her nest with pollen and nectar to provide for her brood. It’s a race against time and over hurdles such as bad weather, competitors, flower scarcity, pests and parasites. Reproductive success depends on the amount of food available for the young, and here their sex can be the decisive factor. Female bees – like most insects – are in general bigger than males, so they need more food. As these big eaters could be a survival risk, some tinkering may be in order.

A red mason bee (Osmia bicornis) man-made nest with brood cells well-stocked with pollen.

A red mason bee couple. The female is 20-25% bigger than the male © Aka, Wikimedia Commons.

The orchard mason bee or blue orchard bee (Osmia lignaria), a cavity-nesting species from North America, is a valued pollinator of several fruit trees. During the early nesting season, when pollen and nectar are most abundant and mum is in top shape, her offspring comprise mostly females. As the season progresses, flowers become scarce, so she has to work harder to provision her nest. Now the sex ratio tilts towards the smaller males, who have better chances of survival because they need less food (Torchio & Tepedino, 1980).

The scenario is similar for the related red mason bee (Osma bicornis), a Eurasian species, but here parasites play a part. As the nesting season advances, females become less efficient and take more time to gather food, creating opportunities for nest-invading parasites. Females deal with the problem by reducing the amount of food stored, with a corresponding shift in the sex ratio towards the less demanding sons (Seidelmann, 2006). In the case of the Australian endemic banksia bee (Hylaeus alcyoneus), the growing food scarcity causes the reduction of the brood’s body mass and a shift in their sex ratios. But contrary to the prevailing pattern found in bees, male banksia bees are significantly larger than females. So unsurprisingly, the energetically cheaper daughters became more abundant late in the season (Paini & Bailey, 2002). Other cavity-nesting bees have also shown declines in foraging efficiency as the season progresses, and these changes have been linked to reduced size of their offspring and shifts in their sex ratios.

Seasonal variation in sex ratio of emerging banksia bee adults (sex ratio = number of males/total number of emerging adults) © Paini & Bailey, 2002.

A male banksia bee. They become progressively scarce in coastal areas of southern Australia as the season advances © The Packer Lab, Wikimedia Commons.

The facultative, condition-dependent shift of sex ratios is a remarkable survival tool. The power to quickly tilt the offspring’s sexual balance could make the difference for a species’ success. In the non-nonsense, unforgiving great outdoors, where long-term existence hangs on the ability to adapt to changes, boys and girls are not always equally valued: these are the times when a Sophie’s choice of sorts is necessary.

JAC note:  Just to put an evolutionary-genetic gloss on this, the changes of sex ratio with environmental or other conditions are the result of evolution. That is, those individuals having genes enabling them to adjust the sex ratio in adaptive ways leave more copies of their genes than individuals who can’t adjust their offspring’s sex ratio. Or, to be even more accurate, genes that affect sex ratio in adaptive ways leave more copies of themselves than genes which can’t do that.

A 2023 expedition to the Pacific Ocean, searching for debris from a suspected extraterrestrial object, may have been looking in the wrong place. A new look at the infrasound data used to locate the point of impact suggests that they may have been confused by the rumblings of a truck driving past.

On 14 January 2018, a space rock hit the Earth’s atmosphere off the coast of Papua New Guinea. It was detected by what are mysteriously described as “US Government Sensors”, and given the catalogue entry “CNEOS 2014-01-08”. Based on the brightness of the fireball and its apparent speed, the physical rock likely survived without burning up completely. The observation was logged in a database kept by the Center for Near Earth Object Studies. Bolides like this can be a spectacular sight, when spotted by human eyes, but they are not rare; several are detected each week.

Extrasolar objects

A few years later, Oumuamua was discovered. Oumuamua was traveling at a high speed, along a path that showed it was not orbiting the Sun. Instead, it had come from interstellar space and was merely passing through. This was very exciting because it was the first time anybody had observed an interstellar rocky object, and so it attracted a lot of attention.

Some observations showed that Oumuamua’s path wasn’t steady, but kept making tiny changes. Most scientists agreed that this was almost certainly because of pockets of ice melting and jetting away in the Sun’s heat. This is a common phenomenon, that we often see happening with comets. More detailed observations and simulations showed that it had a long and skinny shape, more like a splinter than a boulder, which is very unusual among the asteroids and comets that we’re used to. But Oumuamua only really hit the mainstream press when a well-known and prestigious astrophysicist decided, in a surprising leap of logic, that all these details proved that it could be an alien spacecraft!

The Oumuamua discovery led many scientists to start searching for other interstellar objects. CNEOS 2014-01-08, with its high reported speed, looked like a promising candidate. The physicist who had made such a big deal about Oumuamua being artificial took a closer look at the bolide reports and concluded that it must have been traveling fast enough to be another extrasolar object. This claim was controversial, not only because the government sensors appear to be classified and so cannot be verified, but because meteor speeds are notoriously difficult to measure. Observers have mistakenly reported extrasolar meteors as far back as 1951!

But if CNEOS 2014-01-08 truly was from outside the Solar System, and we could find pieces of it, that would be an incredible discovery: The first actual geological samples from a planetary system outside our own!

The expedition

This is why an expedition was launched in 2023 to try and find it. The research team used seismic and infrasound data from seismic research stations in the area to try and find the exact place where the meteoroid would have splashed into the sea. They identified two likely signals from Geoscience Australia’s Passive Seismic Network. The signals were recorded by Manus Island, Papua New Guinea (AU.MANU) and Coen, Queensland, Australia (AU.COEN), at around the same time that the fireball was detected. They triangulated a precise location based on those recordings, and sailed out to search the ocean floor.

The expedition was widely reported as a success, after they found “metallic spherules”. These spherules had an unusual composition, which the expedition leader said was proof of a possible extraterrestrial origin. Like the speed calculations, though, this interpretation was widely challenged. Specialists in other fields have weighed in to argue that there was nothing unusual about the debris, and that various natural and human processes could have created them (My personal favorite: 19th century pollution!). With so much doubt as to where the spherules came from in the first place, it’s probably not wise to say that they are of “extraterrestrial technological” origin.

The area near the seismic station in Manus Island, based on satellite images. Image credit: Roberto Molar Candanosa and Benjamin Fernando/Johns Hopkins University, with imagery from CNES/Airbus via Google. The truck

The most recent challenge to the results of this expedition come from a team led by Dr Benjamin Fernando of Johns Hopkins University. Their report focuses on the seismic and infrasound data used to locate the impact site.

They noticed a number of problems with the expedition’s analysis, starting with the fact that none of the detections happened within 30 seconds of the fireball. But beyond that, these stations are located in the Pacific Ring of Fire, which is very tectonically active. They detect a great many earthquakes and other natural seismic events every day, and some of these happened at the same time as the meteorite impact. Separating the two signals is hard to do without distorting both of them. This adds a lot of error to any calculations based on those data.

Along with seismic data, these stations also have infrasound detectors, meant to detect and monitor nuclear weapons tests. But infrasound has a limited range, and is strongly affected by geography.

Fernando’s team concluded that only one station recorded an infrasound signal that could have come from CNEOS 2014-01-08, and that none of the seismic detections had anything to do with the bolide. Based on this, they believe that the expedition was looking in the wrong place, and that the debris they discovered had nothing at all to do with the 2014 bolide.

But their most damning claim is this: The strongest signal had an unusual pattern, lasting a long time and coming from a direction which changed halfway. They noticed that there is a road passing near the station, with a curve in it that matches the change in direction of the signal. They point out that the signals recorded by trucks driving that road are a far closer match than any natural event.

In other words, they believe that the expedition based its search location for an extraterrestrial meteoroid on the noise of somebody in a truck going for a drive.

In their defense

It’s tempting to laugh at the researchers on the expedition, especially since their leader was a respected astrophysicist who has recently developed a reputation for having crackpot ideas about aliens. But I think there is value in investigating these questions.

It’s easy to get tired of cranks and fools wasting our time with conspiracy theories and crazy stories about abductions. And we should always be skeptical of any claims about aliens, given what we know about the physics of interstellar travel and the absurd scale of the Universe.

But most astronomers agree that life has to exist elsewhere in the Universe, and many think that it could well be intelligent and technologically capable, like us. Nobody’s saying that they can’t possibly exist, only that it’s extremely unlikely that they are over here!

So we should be skeptical of these reports. It’s good to not waste too much time studying them, when there are other mysteries that are far more likely to be true. But that doesn’t mean we should ignore the possibility altogether. It would be disastrous if, by some chance, it turned out to be real, and the scientific community had simply refused to acknowledge it! When new evidence comes in, we must revisit our assumptions and go back and check our previous conclusions. And it’s important that somebody do this even when we’re certain that they’ll get a negative result.

To learn more, visit https://hub.jhu.edu/2024/03/07/alien-meteor-truck/

The post The Sound of an Interstellar Meteor Might Have Just Been a Rumbling Truck appeared first on Universe Today.

I recently pointed out that there are unfamiliar types of standing waves that violate the rules of the standing waves that we most often encounter in life (typically through musical instruments, or when playing with ropes and Slinkys) and in school (typically in a first-year physics class.) I’ve given you some animations here and here, along with some verbal explanation, that show how the two types of standing waves behave.

Today I’ll show you what lies “under the hood” — and how you yourself could make these unfamiliar standing waves with a perfectly ordinary physical system. (Another example, along with the relevance of this whole subject to the Higgs field, is discussed in chapter 20 of the book.)

Strings, Balls and Springs

It’s a famous fact that an ordinary string bears a close resemblance to a set of balls connected by springs — their waves are the same, as long as the wave’s shape varies slowly compared to the distance between the balls.

Figure 1: (Top) A length of string. (Bottom) A set of balls connected by springs. The vertical waves of the ball-spring system are similar to the vertical waves on the string; see Figure 2.

The string remains continuous, rather than fragmenting into pieces, because of its internal atomic forces. Similarly, in the ball-spring system, continuity is assured by the springs, which prevent neighboring balls from moving too far apart.

Both systems have familiar standing waves like those on a guitar string, but only if their ends are attached and fixed to something. The most familiar standing wave, shown for each of the two systems, is displayed below.

Figure 2: The classic standing wave for the string and for the the ball-spring system A Different Set of Balls and Springs

Figure 3 shows a different system of balls and springs, unlike a guitar string. Here, the two sets of springs have distinct roles to play.

Figure 3: A set of balls connected to each other by horizontal springs and to the ground by vertical springs. The waves of this system are less familiar.

• The horizontal springs again assure continuity — they prevent neighboring balls from moving too far apart, and keep the set of balls behaving like a string.
• The vertical springs provide a restoring effect — they pull or push each ball back toward the position it holds in the figure.

It’s the restoring effect that gives this system unfamiliar standing waves.

Compare The Waves

These systems can exhibit many types of waves, depending on whether their ends are fixed or allowed to float (“boundary conditions”). We can have some fun with all the different options at another time. But today I just want to convince you of the most important thing: that the first system of balls and springs requires walls for its standing waves, while the second one does not.

I’ll make waves analogous to the ones I made in last week’s post on this subject. In the animations below, horizontal springs are drawn as orange lines, while vertical ones are drawn as black lines.

First, let’s take the system with only horizontal springs, distort it upward only in the middle, and let go. No simple standing wave results; we get two traveling waves moving in opposite directions and reflecting off the walls (shown as red, fixed dots.)

Now let’s take the system that has vertical springs as well. In particular, let’s make the vertical springs strong, so that the restoring effect is powerful. Again, let’s distort the system upward at the center, and let go. Now the restoring force of the vertical springs creates a standing wave. That wave is nowhere near the walls, and doesn’t care that there are walls at all. It gradually spreads out, but maintains its coherence for many vibration cycles.

The stronger the vertical springs compared to the horizontal springs, the faster the vibration will be, and the slower the spreading of the wave — and thus the longer the standing wave will maintain its integrity.

The Profound Importance of the Restoring Effect

The key difference, then, between the two systems is the existence of the restoring effect of the vertical springs. More specifically, the two types of springs battle it out, the restoring effect fighting the continuity effect. Whether the former wins or the latter wins is what determines whether the system has long-lasting unfamiliar standing waves that require no walls.

In school and in music, we only encounter systems where the restoring effect is absent, and the continuity effect is dominant. But our very lives depend on the existence of a restoring effect for many of nature’s fields. That effect provides the key difference between photons and electrons (see chapters 17 and 20) — the electromagnetic field, whose ripples are photons, experiences no restoring effect, while the electron field, whose ripples are electrons, is subject to a significant restoring effect.

As described in chapter 20 of the book (which gives other examples of a systems with unfamiliar standing waves), this restoring effect is intimately tied to the workings of the Higgs field.

An analysis of viral genomes shows it is more common for viruses to jump from humans to other animals than the other way around

On March 16 surgeons transplanted a kidney taken from a pig into a human recipient, Rick Slayman. So far the transplant is a success, but of course the real test will be how well the kidney functions and for how long. This is the first time such a transplant has been done into a living donor – previous experimental pig transplants were done on brain dead patients.

This approach to essentially “growing organs” for transplant into humans, in my opinion, has the most potential. There are currently over 100 thousand people on the US transplant waiting list, and many of them will die while waiting. There are not enough organs to go around. If we could somehow manufacture organs, especially ones that have a low risk of immune rejection, that would be a huge medical breakthrough. Currently there are several options.

One is to essentially construct a new organ. Attempts are already underway to 3D print organs from stem cells, which can be taken from the intended recipient. This requires a “scaffold” which is connective tissue taken from an organ where the cells have been stripped off. So you still need, for example, a donor heart. You then strip that heart of cells, 3D print new heart cells onto what’s left to create a new heart. This is tricky technology, and I am not confident it will even work.

Another option is to grow the organs ex-vivo – grow them in a tank of some kind from stem cells taken from the intended recipient. The advantage here is that the organ can potentially be a perfect new organ, entirely human, and with the genetics of the recipient, so no issues with rejection. The main limitation is that it takes time. Considering, however, that people often spend years on the transplant wait list, this could still be an option for some. The problem here is that we don’t currently have the technology to do this.

Similar to this approach is to grow a human organ inside an animal – essentially using the animal as the “tank” in which to grow the organ. The host animal can then provide nutrition and oxygen, and a suitable environment. This would require that the animal will not reject the organ, which would mean treating with drugs or engineering animals hosts that are humanized or whose immune systems cannot mount a rejection.

The most futuristic and also ethically complex approach would be to clone an entire person in order to use them as an organ donor. This would not have to be like “The Island” movie in which the cloned future donors were living people kept in a controlled environment, unaware of their ultimate fate. Anencephalic humans (without brains) could be cloned and grown, and just kept as meat bags. There are two big disadvantages here. The first is that the clones would likely need to be kept alive for years before the organs would be mature enough to be used. How would that work? Would a recipient need to wait 10 years before they could get their donor organ, or would there be clone banks where clones were kept in case they were needed in the future? These seem like cost-prohibitive options, except for the super wealthy.

One potential solution would be to genetically engineer universal donors, whose organs could potentially be transplanted into any human recipient. Or perhaps there would need to be a finite number of donors, say for each blood type. When someone needs an organ they get the next one off the rack. Still, this seems like an expensive option.

The other main limitation of the clone approach is the ethical considerations. I doubt keeping banks of living donor clones will be morally acceptable to society, at least not anytime soon.

This leaves us with what I think is by far the best option – genetically engineering animals to be human organ donors. Pigs are good candidates because the size and shape of their organs are a good match. We just need to engineer them so their immune systems use human proteins instead of pig proteins. We can remove any of the proteins that are most likely to trigger rejection. This also means giving the pigs a human immune system. The pigs are therefore both humanized and altered so as not to trigger rejection. Slayman will still need to take anti-rejection drugs, but it is easy to imagine that as this technology incrementally improves eventually we will get to a population of pigs optimized for human organ donation. The advantages of this approach over all other approaches are simply massive, which leads me to predict that this approach is the one that will win out for the foreseeable future.

One potential ethical objection is from raising domestic animals for the purpose of being slaughtered, which some animal rights activists object to. But of course, we already do this for food. At least for now, this is ethically acceptable to most people. Slaughtering a pig not just for food but to save the lives of potentially 5-7 people is not a hard sell ethically. This approach could also be a huge money saver for the healthcare system.

I am therefore very happy to see this technology proceed, and I wish the best for Slayman, both for him personally and for the potential of this technology to save many lives.

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