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Researchers developed an artificial intelligence (AI) model that could help electrical grids prevent power outages by automatically rerouting electricity in milliseconds. The approach is an early example of 'self-healing grid' technology, which uses AI to detect and repair problems such as outages autonomously and without human intervention when issues occur, such as storm-damaged power lines.

Researchers developed an artificial intelligence (AI) model that could help electrical grids prevent power outages by automatically rerouting electricity in milliseconds. The approach is an early example of 'self-healing grid' technology, which uses AI to detect and repair problems such as outages autonomously and without human intervention when issues occur, such as storm-damaged power lines.

Astronomers uncovered that a well-known X-ray binary, whose exact nature has been a mystery to scientists until now, is actually a hidden ultraluminous X-ray source.

Researchers develop the first-ever device powered by blood to measure blood electrical conductivity.

Researchers develop the first-ever device powered by blood to measure blood electrical conductivity.

The history of how stars and galaxies came to be and evolved into the present day remains among the most challenging astrophysical questions to solve yet, but new research brings us closer to understanding it. New insights about young galaxies during the Epoch of Reionization have been revealed. Observations with the James Webb Space Telescope (JWST) of the galaxy Cosmic Gems arc (SPT0615-JD) have confirmed that the light of the galaxy was emitted 460 million years after the big bang. What makes this galaxy unique is that it is magnified through an effect called gravitational lensing, which has not been observed in other galaxies formed during that age.

Researchers have developed a way to create complex devices with multiple materials -- including plastics, metals and semiconductors -- all with a single machine. The research outlines a novel 3D printing and laser process to manufacture multi-material, multi-layered sensors, circuit boards and even textiles with electronic components.

People don't realise just how bad our antibiotic resistance problem is, says Jeanne Marrazzo, the top infectious disease specialist in the US

We are all too aware of the pollution on planet Earth. There are increased amounts of plastic and garbage on the world’s beaches and debris littering the oceans. Until now, it was thought that satellites weren’t capable of tracking marine debris but a supercomputer algorithm challenges that. 300,000 images were taken every three days at a resolution of 10 metres and were able to identify large concentrations of debris. 

Upper estimates of plastic in our oceans peak at around 200 million tons! Every day it is believed another 8 million pieces of plastic make their way into the marine environment. Now, a study led by a team at the Institut de Ciencies del Mar at the University of Cadiz believe it may be possible to study and track the surface debris in the oceans. Using supercomputers and advanced algorithms, the team have shown that satellites can indeed be used. 

Using data from the European Copernicus Sentinel-2 satellite, a total of 300,000 images of the Mediterranean Sea were analysed. The images were taken every 3 days at a resolution of 10 metres. Typically of course, there is not much debris in the sea which is that big but accumulations of debris have grown to that size. The aggregations are known as ‘windrows’ and have built up as ocean currents and winds bring debris together to form large structures. 

The output from the study reveals the most polluted areas of the Mediterranean and the main entry points from the mainland. It will help us to improve our understanding of the processes and mechanisms that transport debris across the ocean and even help us to perhaps predict movement. The results also show that the amount of debris in the Mediterranean covers around 95 square kilometres.

Eastern Mediterranean Sea Area June 1993

Unfortunately the research does not help resolve the issue of pollution but it does help us understand the scale. The team propose future satellites should be equipped with detectors to monitor the debris. It would increase the ability to detect plastic in the open ocean by a factor of 20 and help to model the impact of marine pollution on first, tourism and the marine ecosystem. 

One element of the studies conclusion is that population density, geography and rainfall patterns play an important part in the accumulation of marine litter. Dry arid lands like deserts that play host to cities seem to contribute much less to marine litter while those that are much more temperate with higher rainfall seem to contribute more. 

It is also interesting to note that the majority of litter that originates from land masses seems to be confined to 15 kilometres form the coast and subsequently returns after a few days of months. The team conclude that satellite based monitoring is an essential element in our battle against litter in the ocean. The technology can also be used for the detection of other floating objects such as the loss of ships, oil spills and even search and rescue elements. 

Source : Satellites to monitor marine debris from space

The post Satellites are Going to Track Garbage Drifting Across the Oceans appeared first on Universe Today.

I’m tired of Bret Weinstein pushing conspiracy theories, and just as tired of him making proclamations about evolutionary biology that are misleading or flat wrong.  I’m especially peeved today because, in the video below, he claims that both Richard Dawkins and I have said that “evolution biology is settled” because I, at least, claimed that the big advances at the beginning of the field, involving people like Darwin, Fisher, Haldane, Sewall Wright, and Ernst Mayr, established the foundations of the field, and we don’t see such big advances any more.  Where are today’s Darwins? (This was a question posed to me by Dick Lewontin when I interviewed him some years ago.) And yes, I probably said that and do believe it. But that doesn’t mean that evolutionary biology is “settled”. It’s that our approach to understanding evolution in nature has been somewhat asymptotic, with a big leap at the beginning and then incremental progress since the 1940s.  Indeed, I think that advances such as the “modern synthesis” of the 1930s and 1940s, showing that Darwinian natural selection was compatible with modern genetics, was a huge synthesis that hasn’t been equaled. And, of course, science of any sort never reaches an asymptote, for that would be “complete understanding: the ultimate truth,” which is unattainable.

In the video below, Weinstein and Heying argue that Dawkins and I think that evolutionary biology is “settled,” and that our view impedes progress in the field, allows evolutionary biology to stagnate, and, most important, impedes people’s failure to take Intelligent Design theory seriously for raising serious problems with neo-Darwinism.  Further, he says that we’ve discouraged graduate students from entering the field and have not produced, as mentors, our “replacements.” He’s dead wrong here, at least for me: I’d put my graduate students (and their graduate students) up against anybody’s as having made substantial progress in evolutionary genetics.

Yes, we have nobody around today who’s made advances as big as those of Darwin or Fisher. But that doesn’t mean at all, as Weinstein and Heather Heying assert in the video below, that we think evolutionary biology is “settled.”  Far from it! First of all, neutral theory was a big step forward in evolutionary genetics, and that was introduced in 1968 and is still being developed.  We still don’t understand exactly why organisms reproduce sexually; we don’t understand how often speciation occurs without geographic isolation; we don’t understand what females, during sexual selection, are looking for when they choose a mate. I could list tons of other questions, but these are three that I’ve written about and are mentioned by Weinstein.

Weinstein and Heying’s claim in the video is that there are huge advances, on the scale of Darwin’s and Fisher’s, to be made, perhaps by people who are working in intelligent design. (Weinstein implies that he has a theory that may be on this scale as well.) To be sure, they note that the IDers like Stephen Meyer and his “high-quality colleagues”, are motivated by religion, but Weinstein sees them still asking important and serious questions that evolutionists haven’t answered, thus motivating evolutionists to better understand nature.  Nope. ID adocates have wasted the time of evolutionists in refuting IDer’s specious arguments. Why do they do this? To let the credulous public, much of which buys ID, know that science can answer those criticisms.  That’s why there were so many critiques of Michael Behe’s books by reputable scientists.

Three questions that evolutionists have supposedly set aside and neglected are these: “What caused the Cambrian explosion?”, “Why are there gaps in the fossil record?” and “How can we get complex working proteins when their existence is so improbable?”

The answer to the first question is “We don’t know, but there are theories and some of them are being tested.”

The second question has a spate of possible answers (lack of sediment deposition, rapid evolution in relatively short evolutionary times, and so on). But one thing we know is that Gould’s explanation—the theory of punctuated equilibrium—is not likely to be the answer, as the theory doesn’t work. (People don’t often realize that punctuated equilibrium, as advanced by Gould and Eldredge, is more than just a jerky pattern in the fossil record: it’s also a theory about why the pattern is supposedly ubiquitous. The ubiquity of the pattern in fact is still being argued, but we know that it’s not ubiquitous.) But in the end, Gould’s explanation—the really novel and non-Darwinian part punctuated equilibrium—was simply wrong.

As for the third question, the claim that the origin of complex proteins is improbable is not one taken seriously by molecular evolutionists, simply because we have no indication that it really is a problem. The idea that it is a problem comes from specious claims of IDers that such proteins assemble themselves randomly rather than by selection, or that mutation is too unlikely to fuel the process (there are other fuels, of course, like gene duplication and insertions of DNA).

At 2:56, in the video below, Weinstein asserts that evolutionary biologists have simply left the Big Questions “on the table”, questions like “where did all the species come from?” and “why do females put males in so many species to challenges that then cause them to burden their male offspring with elaborate displays that are not helpful?”

Weinstein is apparently unaware that I wrote a comprehensive and scholarly book on speciation in 2004 and outlined a lot of unanswered questions, so no, Dr. Weinstein, I did NOT think that the question “wasn’t worthy of my time”. And yes, we do have considerably more understanding these days about how species form. That’s also described in the book.

He’s also apparently unaware that many biologists have been working on sexual selection, which is simply a hard problem to test in nature. And he doesn’t understand that elaborate displays by males are helpful: they help males get mates. Peacocks with more “eyes” in their tails, for example, get more offspring. Widowbirds whose tails are artificially elongated by gluing on extra feather get more mates, too.  Weinstein is ignorant about how sexual selection works, and how theories about it have been tested.

At any rate, I no longer take Weinstein seriously as a biologist, or even as an intellectual. He may have been a good teacher at Evergreen State, but he’s not on the rails when it comes to evolutionary biology (his last peer-reviewed paper was in 2005, and Researchgate lists 4 total publications). He’s also advanced specious theories about ivermectin being both a good preventive and cure for Covid, he’s suggested that AIDS was caused by party drugs and not a virus, and he’s suggested that the death of Nobel Laureate Kary Mullis was suspicious, perhaps because Mullis has criticized Anthony Fauci (did Fauci order a hit? LOL!).  Weinstein’s even wrapped his cameras in aluminum foil because he suspected some sinister forces were impeding his transmission. He gave his cameras tinfoil hats!

A tweet from Michael Shermer, aimed at Weinstein, about Kary Mullis’s death:

In his Substack column below, Jesse Singal shows other conspiracy theories/dubious theories that Weinstein and Heying have advanced (Weinstein is more vociferous than Heying, so I give him most of the opprobrium). Click to read:

Here you can see Weinstein going after Dawkins and me by misrepresenting our views. Yes, I do think that understanding of evolution has slowed down since Darwin and since the 1940s, since most of these “founders” seem to have gotten the major parts of the modern synthesis right—except for neutral theory, which was a huge advance. But I surely do not believe (nor do I think that Dawkins believes) that we have pretty much completed our understanding of evolution. But I’ll let Dawkins speak for himself.

And of course the IDers love Weinstein and Heyer’s podcast, because they give so much credit to Intelligent Design in pinpointing the “neglected” Big Questions about evolution.It’s thus a pity that IDers, like Weinstein himself, hardly have any peer-reviewed papers in real scientific journals advancing their theories! Read below to see how much IDers love Weinstein.

 

Now I surely don’t think that Weinstein is stupid at all; he’s really quite smart. But I think that, in his desire to find a niche for himself, and garner a measure of public approbation, he’s deliberately embraced conspiracy theories, highly praised the gussied-up creationism of Intelligent Design, and, most annoying, almost willfully misunderstood evolutionary biology.

By representing data as folds in paper, the principles of origami can theoretically be used to compute anything imaginable

When the planet Mercury formed 4 billion years ago, conditions may have been just right to form a thick layer of diamonds below its surface

Astronauts are considered by many to be an elite bunch of people; healthy, fit and capable in many disciplines. Went they travel into space they can face health issues related to weightlessness from reduction in bone density to issues with their eyesight. These are people at the peak of physical fitness but what will happen to the rest of us when space tourism really kicks off. It is likely that anyone with underlying health issues could worsen in space. A new study suggests those with cardiovascular issues may suffer heart failure in space!

Space travel and automatic intelligence (AI) are two fabulously interesting topics. Combine them and you have a fascinating story. Dr Lex Van Loon from the Australian National University has been using AI and mathematical models to explore human physiology and the impact of space exploration. In a recent study he created digitally identical AI twins, one with an underlying heart condition. 

The interest driving the study is the advancement toward space tourism and the opening up of space to those less physically fit than astronauts. As space travel becomes more available to the mass population we will start to see a shift in demographic of space travellers to older, more wealthy individuals but they are more likely to have health issues. We will eventually see people with a whole multitude of conditions wanting to holiday in space, but what are the likely impacts. 

ESA astronaut Alexander Gerst gets a workout on the Advanced Resistive Exercise Device (ARED). Credit: NASA

Microgravity causes a redistribution of fluids around the body and can cause conditions like ‘puffy face bird leg syndrome.’ The name aptly describes the effect, the face swells up and the legs thin. It results in an increase in venous pressure in the upper body, this is fine for healthy people but heart failure sufferers are at a much higher risk. Given that there are over 100 million people around the world that suffer heart failure it is essential this is explored. 

Looking at the wide spectrum of heard failure, conditions can be grouped into two categories; a weak hart that cannot pump effectively and a heart that cannot relax and fill properly. All possible conditions need to be studied with specific ways to treat and mitigate the risk during space travel. 

This is a study that is difficult to collect real data in space so we have to turn to computer modelling to simulate the effects. The team led by Dr Loon showed that a microgravity environment leads to an increase in cardiac output (the quantity of blood pumped by the heart in a given period of time.) This is not a problem for most people but with heart failure patients it is accompanied by a rise in pressure in the left atrial region of the heart, to dangerous levels. If left unchecked, it can lead to a condition where fluid accumulates in the lungs known as a pulmonary edema, making it difficult to breathe!

With the increase in corporate interest in space travel, space tourism is slowly becoming a reality. People can already pay for trips into space but as costs come down, the number of people heading out into space will increase. Eventually, trips into space will be as common as trips to other countries. It is imperative we understand the impact on our health and what we can do to make space as widely accessible as possible without putting our health at risk. 

Source : Heart failure in space: scientists calculate potential health threats facing future space tourists in microgravity

The post Will Space Tourists Be Getting Heart Attacks in Space? appeared first on Universe Today.

For those of you currently in western Massachusetts or eastern upstate New York, some news: I’ll be speaking about my book today, Monday, June 24th, 5:30 pm, in Lenox, MA. At this free event, held at the local institution known simply as “The Bookstore“, I’ll read from the text and discuss its central message. After that, I’ll answer questions from the audience and sign books.

In other news — for those of you waiting (im)patiently for the audiobook, I am glad to report that there is finally some forward movement on that front. I’m still not sure how long it will take for the audio version to become available, but progress should be steady and rapid from here.

I know it’s only been a couple of weeks since I wrote about cement, but now I need to write about concrete, or potential version of concrete that is able to function as a battery. If we can get the technology to work this could an extremely useful item for a future of green energy.

The idea is one example of a more general idea – making structural material that can double as energy storage, either as a battery or supercapacitor. Imagine, for example, if the frame of your car was its battery. Similarly, imagine if the foundation of your house was a massive supercapacitor. That is the idea behind an MIT research project, which right now is in the proof-of-concept laboratory phase.

The researchers added carbon black to cement and the usual other ingredients to make concrete that can function as a supercapacitor. The carbon black is highly conductive, and it can form many branching tendrils in the concrete. These conductive bits are separated by insulating bits – and that is the basic structure of a capacitor. Charge can build up in the conductive carbon black and be maintained by the insulating layers.

At this point their test material can store 300 watt hours per cubic meter. A typical US home uses about 30 kwh per day, so would need 100 cubic meters to have one day’s worth of energy storage. That is in the order of magnitude of the volume of concrete in a, say, 1,500 sq foot home’s foundation (about 50 cubic meters). Larger homes would have larger foundations, and of course the foundations can be made deliberately thick to increase the storage. In other words, this is a useful amount of energy, theoretically. Any incremental advances in energy density would also be very useful, and the researchers are working on that.

The state of the research is still preliminary – proof of concept. One of the authors, Damian Stefaniuk, said the magic words in the BBC interview – “If it can be scaled up, the technology can help solve an important issue – the storing of renewable energy, ” – those fateful words that have killed many a promising new technology – if it can be scaled up. There are some issues that need to be worked out. One is, the more carbon black in the mixture the greater the energy density of the resulting capacitor, but the lower the strength of the resulting concrete. So there is a sweet spot where these tradeoffs are balanced. Of course, we may be able to combine this technology with one of the cement technologies I wrote about earlier that increase the strength of concrete.

Supercapacitors vs batteries also have some interesting tradeoffs. Supercapacitors can store energy very quickly, and don’t degrade over time like batteries do. But they also tend to release their energy quickly, rather than at a slow steady pace over a long period of time. Being able to control the rate of energy release will have to be built into the overall device somehow. Again this is something the researchers are working on by playing with the recipe.

But the big thing is – we simply don’t know what will happen when you start building foundation-sized slabs of this capacitor concrete. How will it function? And what happens when you fill it up with energy? Will the entire foundation need to be insulated in some way? What will this do to the cost of construction? Will this be economically feasible? What is the longevity of the resulting concrete and its energy storage? There are lots of potential deal-killers here. But none are absolute any they may all be solvable with continued development of this technology.

Now let’s play what if. What if this technology ultimately works, is reasonably cost effective (costing no more than adding any other battery storage to a home, let’s say), with reasonable capacity (1-2 days of backup power for a typical home), and there are no deal-killers? What are the likely applications? Obviously, the one I have been discussing – making the foundation of any building into a giant energy-storing supercapacitor. This won’t be viable as a retrofit so only will apply to new buildings going forward. But eventually it would be nice if, say, all new homes came with solar panel roofs and energy storage foundations.

I could also see this being used for grid storage. You know what else needs foundations – wind turbines. Land-based wind turbines need large foundations, with about 700-800 cubic meters of concrete. Let’s say we build a generous foundation with 1000 cubic meters of energy storing concrete. That’s 300 kwh of energy storage, enough to power 10 homes for a day. Perhaps we make deliberately huge concrete foundations for them, making them more stable but also adding energy storage, say 10,000 cubic meters (3 mwh). Multiply that by the more than 70,000 wind turbines in the US and we have 210 gigawatt hours (GWh) of grid storage. The US uses about 11 TWh per day. So that would be about 30 minutes of energy storage for the entire country (I think I did all those calculations correctly but feel free to double check me). This level of storage is useful for short term energy shifting and balancing the grid.

We could also build foundations for fields of solar panels. I wonder if a version of this material could be strong enough for a dam that is part of a hydroelectric plant. What about the containment vessel for a nuclear power plant, or part of a geothermal plant? Any giant construction is likely to use a lot of concrete, and could theoretically double as energy storage.

We could also theoretically make roads out of a version of this material. Could this lead to the infamous “solar roads”? In this more plausible version the roads themselves will not be photovoltaics but just energy storage, while solar panels, or some other energy source, will be placed more optimally. But powered roads could be interesting, allowing for recharging of electric vehicles while driving, or led road signs. I doubt this will happen, and I have questions about what a charged road would be like. What happens if you walk on it? Is the surface entirely insulated, and if so, how does it charge cars? Would we need to also incorporate wireless charging technology into the roads?

As I wrote in the previous article, the world produces 4.4 billion tons of concrete each year. If some of that is energy storage concrete that could go a long way to fill our energy storage needs. It’s also better than using lithium or other limited resources that we need for high specific energy batteries for cars. But for now we are in the “if it can be scaled up” phase.

 

 

 

The post Concrete Battery first appeared on NeuroLogica Blog.

A study of small city gardens in the Netherlands found insects were just as abundant in those with exotic plants as in those filled with native plants

My former science idol John Ioannidis has published a paper citing a Delphi consensus statement on COVID-19 as evidence that the scientific community is "biased" against his anti-"lockdown" pro-virus views. The descent continues apace.

The post “‘Panel stacking”: John Ioannidis versus a Delphi consensus statement on COVID-19 first appeared on Science-Based Medicine.

Four years ago, the supermassive black hole hidden in the heart of galaxy SDSS1335+0728 roared awake and announced its presence with a blast of radiation. It marks the first time astronomers witnessed a sudden activation of a supermassive black hole in real time.

“Imagine you’ve been observing a distant galaxy for years, and it always seemed calm and inactive,” said Paula Sánchez Sáez, an astronomer at ESO in Germany and lead author of the study of this object. “Suddenly, its [core] starts showing dramatic changes in brightness, unlike any typical events we’ve seen before.”

This is what happened to SDSS1335+0728, which is now officially classified as having an active galactic nucleus (AGN). It experienced what’s called a “nuclear transient.” Essentially, that means the galaxy now has a very bright compact region. However, it wasn’t always that bright and astronomers want to understand what caused it to wake up.

This artist’s impression shows two stages in the formation of a disc of gas and dust around the massive black hole at the center of the galaxy SDSS1335+0728. The core of this galaxy lit up in 2019 and keeps brightening today — the first time astronomers observed a massive black hole become active as it happened. Credit: ESO/M. Kornmesser Looking for Transients in all the Right Places

The unusual brightness variations were detected by the Zwicky Transient Facility in California, which gives constant, real-time alerts about such things as transient flaring and brightening in the hearts of galaxies like SDSS1335+0728. In addition, several other facilities observed the variations, too, and brightness changes were found in archival data from several other observatories.

The sudden brightenings could be due to many things, including the cannibalization of stars and clouds of gas that stray too near supermassive black holes. How often they brighten and how a quiescent galaxy nucleus changes to an active one are topics that astronomers are using such surveys and observations to understand. They’re looking not just at distant galaxies, but activity within the neighborhood of our own galaxy’s supermassive black hole, too.

A Galaxy and Its Supermassive Black Hole

Most galaxies have stupendously massive black holes at their hearts. They typically sequester away at least a hundred thousand times the mass of the Sun (sometimes more). It’s all trapped by gravity and nothing ever escapes, not even light. “These giant monsters usually are sleeping and not directly visible,” said study co-author Claudio Ricci, from Chile’s Diego Portales University. “In the case of SDSS1335+0728, we were able to observe the awakening of the massive black hole, [which] suddenly started to feast on gas available in its surroundings, becoming very bright.”

A black hole itself doesn’t emit any light at all. Instead, it sucks everything in, including light. However, the region around the black hole—called the accretion disk—is a pretty active place. It’s where material trapped by the intense gravitational pull of the black hole swirls around like water going down a drain. All that stuff—mostly gas, some dust—is threaded through with magnetic fields. Friction between accretions of the material heats it up. And, that act of heating gives off radiation. If there’s enough of it, we see light being given off. Intense active regions emit x-rays, which indicate the level of activity.

Gravity’s Slice-and-dice Activity

There’s also something called tidal disruption, which happens when something like a star or a cloud of gas gets trapped in the gravitational field. These things take time—on the order of years to occur. When they happen, the gravitational pull of the black hole eventually rips the star or cloud apart. That also gives off radiation. In fact, a very slow-motion tidal disruption event may be occurring at the heart of SDSS1335+0728. If so, it could be one of the longest and dimmest ones ever seen.

Regardless of what’s causing the brightening, the ultimate fate of some of the material is to end up inside the black hole. The rest of it gets superheated in the accretion disk and signals its fate through increased radiation.

Black Hole Growth and a Wake-up Call

The supermassive black holes in the hearts of galaxies grow from smaller ones to larger ones through mergers. We don’t see those growth patterns in real time, since they occur over millions of years. The merger scenario says that when galaxies come together, their central black holes (if they have them) do, too.

Simulation of merging supermassive black holes. Credit: NASA’s Goddard Space Flight Center/Scott Noble

Eventually you get these gargantuan monsters. They just sit there and nibble away at passing gas clouds to gain additional mass. That’s how they gain mass through acquisitions, which occur over shorter timescales. This is apparently what the one in SDSS1335+0728 is doing now. It’s just not often that astronomers get to see one wake up and start munching away in a short period of time.

So, a lot of questions remain about this one, mostly about its formation history. Since the mergers take a long time, it’s hard to know what’s happened to this one in the past. If this is a tidal disruption event, astronomers want to know how often such things happen.

This artist’s illustration depicts what astronomers call a “tidal disruption event,” or TDE, when an object such as a star wanders too close to a black hole and is destroyed by tidal forces generated from the black hole’s intense gravitational forces. (Credit: NASA/CXC/M.Weiss.)

At the moment, for SDSS1335+0728, there’s no immediate evidence of prior outbursts signaling prior awakenings of the supermassive black hole. Astronomers need to do a lot of follow-up observations to understand what’s really happening there, and perhaps find evidence for other eruptions and activity associated with the black hole, according to Sánchez Sáez. “Regardless of the nature of the variations, [this galaxy] provides valuable information on how black holes grow and evolve,” she said, noting that advanced instruments at ESO’s Very Large Telescope should give astronomers a better idea of the processes occurring at this black hole. In addition, further time-domain all-sky surveys with the upcoming Vera C. Rubin telescope should be able to track this galaxy’s nuclear brightenings.

For More Information

Astronomers See a Massive Black Hole Awaken in Real Time
SDSS1335+0728: The awakening of a ~10^6 M_sun Black Hole
arXiv preprint

The post Astronomers See a Black Hole Wake Up from its Ancient Slumber appeared first on Universe Today.

If approved, donanemab would be the third FDA approved disease-modifying beta-amyloid treatment for Alzheimer’s disease.

The post FDA Advisory Committee Recommends approval of new Alzheimer’s drug Donanemab first appeared on Science-Based Medicine.

Flatfish, in the order Pleuronectiformes, have long been an evolutionary puzzle, for all the fish in this order lie on the substrate—on their sides—with both eyes on one side of their  body, like the flounder below:

By Moondigger – Own work, CC BY-SA 2.5

Phylogenetic analysis shows that flatfish evolved from “regular” fish, fish having one eye on each side and swimming vertically, that evolved over time to lie on their sides. The bizarre thing about this evolution is that it involved genetic changes so that “normal” fish had their eyes move over the top of their head so that both eyes look upwards.  Their skin changes color and texture, too, with the top half colored, as above, and the bottom half pale.

And all flatfish begin their development like “normal fish”, swimming vertically and having one eye on each side of the head. Then, as the fish gets older, one eye migrates over the top of the skull to the other side! (You can see that in the video below.)

When the eyes are both on one side, the flatfish tip onto their sides and spend the rest of their adult life lying on one side. (The side varies among species: some have 100% right-sided individuals, others 100% left-sided, and some species are random, with half of the individuals having the right eye move over (and lying on their right side), and the other half having the left eye move.

Living on the substrate like this, and often camouflaged as the flounder above, is an advantage for the fish, both protecting them from predators and, since they are predatory piscivores (fish eaters), hiding from their prey.

Here’s a video of the development of a young flatfish, showing the eye migration.  Since the ancestor had both eyes on one side, like the young flatfish, this is a case of “ontogeny recapitulating phylogeny”—that is, the development of a single living fish goes through a process mimicking the evolution of their adult ancestors.

But since the weird developmental pathway is presumably an adaptation that evolved by (presumably stepwise) natural selection, two big questions immediately arise:

1. What were the intermediate evolutionary stages of eye migration?
2. What were the evolutionary advantages of this migration, which presumably involved a gradual evolutionary movement of the eye from the side to the top of the head, and then over the head to the other side?  It’s hard to see how, for example, an eye that’s halfway around, so it’s close to the top of the skull but hasn’t moved to the other side, could leave more offspring, or survive better, than their ancestors. What would be the advantage of each small step of the migration?

It’s hard to envision a gradual Darwinian process that could produce this migration. As Carl Zimmer wrote in a new NYT article that summarizes recent flatfish findings (click below), Darwin’s critics used both questions about to cast doubt on his theory.  In response, some “saltationists”, who assumed that major evolutionary changes occurred in one huge step rather than a series of gradual steps, said that a single mutation moved the eye from one side to the other. (But that would not be advantageous unless the fish had already evolved to lie on its side!)

Click below to read the Zimmer piece in the NYT here (the drawing is animated), or find it archived here. 

 

As Carl reports, there was another weird finding that now seems doubtful: a 2001 paper by a group of Chinese researchers who, using DNA=based family trees, seemed to show that flatfish evolved twice.  You can see that paper in Nature Genetics by clicking on the headline below, or read the pdf here.  The discovery that flatfish seemed to be “polyphyletic”—with more than one evolutionarily independent origin—was deeply weird, because the hormone-induced eye migration, which is extraordinarily complex, would have had to evolve twice. It’s not impossible, but seemed unlikely. One of the doubters was evolutionist Matt Friedman, who got his Ph.D. here and is now a professor at the University of Michigan and director of its Museum of Paleontology.

A while back, when he was still at Chicago, Friedman published what I see as the most interesting of the three papers highlighted here. This one was in Nature, and you can read it by clicking below or seeing the pdf here

Note that this paper was a lot of work, and yet, unlike the others, Friedman was the sole author. I love to see single-person research efforts like this.  That aside, what Friedman found were two fossil evolutionary intermediates between adult “normal” fishes (the presumed ancestors of flatfish) and modern flatfishes, having both eyes on one side. Friedman reanalyzed a neglected species, Amphistium paradoxum, and a described a new fossil fish, Heteronectes chaneti, both from the lower Eocene, about 50 million years ago.

Amazingly, both species (the former randomly sided and the latter lying on its left side) showed an intermediate placement of the eyes in the adult fish. Both eyes were on the same side of a vertically-oriented fish, but one eye had migrated upwards toward the top of the skull, so that the fish could presumably see both to the side and also, perhaps, a bit above them.  Thus we have two evolutionary intermediates of the adult stage, likely showing that the eye movement did not occur in one big evolutionary leap.

Here’s a photo from the 2008 paper of the left and right sides of the H. chaneti skull, showing the eye sockets, which I’ve circled.  The asymmetry is obvious:

(from the paper): a, Heteronectes chaneti gen. et sp. nov., holotype, NHMW 1974.1639.25 (dextral morph); transfer preparation dusted with ammonium chloride and presented in right-lateral view. b, Counterpart, NHMW 1974.1639.24; transfer preparation dusted with ammonium chloride and presented in left-lateral view, showing migrated orbit.

And a reconstruction of the Amphistium species, showing both sides. The asymmetry is again clear, but the eyes of the adults are still on opposite sides of the head:

(From the paper): b, Reconstruction of Amphistium, showing sinistral (front) and dextral (back) individuals in the left lateral view (modified from ref. 20)

You’ve probably realized that this addresses question #1 above, showing that the movement was presumably gradual over evolutionary time, though we need more fossils to show that it was a continuous series of small steps. But at least the movement didn’t seem to involve one big leap.

But that leaves question #2, which I’ll address in a moment.

The reason Zimmer’s note came out now, though the papers above date from 2008 and 2021, is that a group of authors recently published another DNA based analysis in Nature Genetics showing that the Chinese group was probably wrong: flatfishes and their eye movements seem to have had a single evolutionary origin. (The Chinese group maintains that their “polyphyly” conclusion is still the best one.)

Click below to read, or find the pdf here.

 

Before returning to the Big Unsolved Question, I’ll show the phylogeny advanced in the 2001 paper (bottom), showing two origins of flattening and eye migration, and the newer analysis by Duarte-Ribiero et al.  at the top (Friedman is the third author), showing a single origin of flatfish (I’ve circled it).  This newer paper also singles out some genes that, showing signs of selection in their DNA sequence, may be involved in the evolutionary transformation, but I’ll leave that issue aside.  Green silhouettes are flatfish, black are nonflat fish.

(Part of it from paper): (From paper, and there’s more): a, FM tree estimated using LEA’s dataset with ASTRAL under an NHM (GHOST) of nucleotide substitution (see Supplementary Note 2 for details on time calibration). b, FP tree illustrates the phylogenetic hypothesis and divergence times proposed by LE

Now for the big mystery.  How could there possibly be an evolutionary advantage to each step of the eye movement? Presumably the adult either laid on its side or swam “normally”, and what would be the advantage of intermediate stages when the eye gradually moved up, across the top of the skull, and settling on the other side?  The movement is presumably advantageous only when the fish is already on its side, but then what would be the advantage of moving a few mm towards the top of the skull?

Well, perhaps the fish didn’t lie fully on its side. Here’s one clue in a quote from the 2008 paper:

Questions about the possible selective advantage of incomplete orbital transit arise from the discovery of stem flatfishes. Clues are given by living taxa, which often prop their bodies above the substrate by depressing their dorsal- and anal-fin rays. Similar behaviour might have permitted Amphistium and Heteronectes—both of which have long median-fin rays—the use of both eyes while on the sea floor. The unusual morphology and resting orientation of pleuronectiforms have been interpreted as adaptations for prey ambus, and it is clear that stem flatfishes, like morphologically primitive living forms, were piscivorous; one specimen of Amphistium (MCSNV V.D.91+92) contains the remains of a fish nearly half its own length.

So perhaps this happened: a normal ancestor, through behavioral evolution, adapted to hanging around the sea bottom, as they were less conspicuous and could get more prey.  But they’d have a more difficult time seeing upwards with eyes on both sides of the head. Movements of the eyes toward the top of the skull could be advantageous so long as they occurred in concert with behavioral changes (first perhaps learned, then evolved) involving propping themselves up with their fins. The advantage of tilting a bit would be that the fish might become a bit less conspicuous.

This whole scenario, as I proposed it (and I’m sure others have before in some form) presumes that the eye movement is either induced by or occurs in concert with changes in the fish’s behavior, which initially could have been learned and not coded in the genes. (Ernst Mayr once said something like “all major evolutionary changes begin with a change in behavior”). I don’t know how to test the hypothesis, as even finding more fossils with intermediate stages of eye migration will tell us little about the selective pressures involved. But for sure the movement involved natural selection rather than other evolutionary forces like genetic drift, for we have a big directional change involving many genes, genes that involve both morphology and behavior.

In short, I don’t know how it happened. But seeing that modern fishes can use their fins to prop themselves up on the sea floor may give us a clue. And other scenarios may be possible; readers can entertain themselves by finding alternative ways this change could have occurred by natural selection.