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Yesterday — 21 December 2024Main stream

Green sea turtle gets relief from “bubble butt” syndrome thanks to 3D printing

21 December 2024 at 12:25

Charlotte, a green sea turtle, was hit by a boat back in 2008. This left it with an affliction colloquially referred to as the “bubble butt,” a kind of floating syndrome that makes it impossible for a turtle to dive. Most sea turtles suffering from issues like this simply die at sea, since the condition leaves them stranded at the surface where they can’t forage, sleep, and avoid predators like sharks. But fate had other plans for Charlotte.

Charlotte didn’t end up as a shark’s lunch and didn’t starve to death floating helplessly in the ocean. Instead, it got rescued shortly after the boat accident and eventually found a home at Mystic Aquarium in Stonington, Connecticut, where it received professional care. That was the first time Charlotte got lucky. The second time came when a collaboration formed: Adia, a company specializing in 3D-printing solutions; Formlabs, one of the world’s leading manufacturers of 3D printers; and New Balance Athletic, a sportswear giant based in Boston. This team chose Charlotte as a technology showcase, which basically turned the turtle into an Oscar Pistorius of the sea—just without the criminal conviction.

Weights and diet

Sea turtles are marine reptiles, which means they don’t have gills like fish—they need air to breathe. The lungs also play a key role in their buoyancy regulation system, which allows them to rest for extended periods of time at the sea floor or float at a precisely chosen depth. A sea turtle can precisely choose the depth at which it achieves neutral buoyancy by inhaling the exactly right volume of air.

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© Laura Shubel

Before yesterdayMain stream

Generating power with a thin, flexible thermoelectric film

12 December 2024 at 19:00

The No. 1 nuisance with smartphones and smartwatches is that we need to charge them every day. As warm-blooded creatures, however, we generate heat all the time, and that heat can be converted into electricity for some of the electronic gadgetry we carry.

Flexible thermoelectric devices, or F-TEDs, can convert thermal energy into electric power. The problem is that F-TEDs weren’t actually flexible enough to comfortably wear or efficient enough to power even a smartwatch. They were also very expensive to make.

But now, a team of Australian researchers thinks they finally achieved a breakthrough that might take F-TEDs off the ground.

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New drone has legs for landing gear, enabling efficient launches

5 December 2024 at 23:34

Most drones on the market are rotary-wing quadcopters, which can conveniently land and take off almost anywhere. The problem is they are less energy-efficient than fixed-wing aircraft, which can fly greater distances and stay airborne for longer but need a runway, a dedicated launcher, or at least a good old-fashioned throw to get to the skies.

To get past this limit, a team of Swiss researchers at the École Polytechnique Fédérale de Lausanne built a fixed-wing flying robot called RAVEN (Robotic Avian-inspired Vehicle for multiple ENvironments) with a peculiar bio-inspired landing gear: a pair of robotic bird-like legs. “The RAVEN robot can walk, hop over obstacles, and do a jumping takeoff like real birds,” says Won Dong Shin, an engineer leading the project.

Smart investments

The key challenge in attaching legs to drones was that they significantly increased mass and complexity. State-of-the-art robotic legs were designed for robots walking on the ground and were too bulky and heavy to even think about using on a flying machine. So, Shin’s team started their work by taking a closer look at what the leg mass budget looked like in various species of birds.

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© EPFL/Alain Herzog

People will share misinformation that sparks “moral outrage”

2 December 2024 at 20:18

Rob Bauer, the chair of a NATO military committee, reportedly said, “It is more competent not to wait, but to hit launchers in Russia in case Russia attacks us. We must strike first.” These comments, supposedly made in 2024, were later interpreted as suggesting NATO should attempt a preemptive strike against Russia, an idea that lots of people found outrageously dangerous.

But lots of people also missed a thing about the quote: Bauer has never said it. It was made up. Despite that, the purported statement got nearly 250,000 views on X and was mindlessly spread further by the likes of Alex Jones.

Why do stories like this get so many views and shares? “The vast majority of misinformation studies assume people want to be accurate, but certain things distract them,” says William J. Brady, a researcher at Northwestern University. “Maybe it’s the social media environment. Maybe they’re not understanding the news, or the sources are confusing them. But what we found is that when content evokes outrage, people are consistently sharing it without even clicking into the article.” Brady co-authored a study on how misinformation exploits outrage to spread online. When we get outraged, the study suggests, we simply care way less if what’s got us outraged is even real.

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© Ricardo Mendoza Garbayo

Teaching a drone to fly without a vertical rudder

27 November 2024 at 18:08

Most airplanes in the world have vertical tails or rudders to prevent Dutch roll instabilities, a combination of yawing and sideways motions with rolling that looks a bit like the movements of a skater. Unfortunately, a vertical tail adds weight and generates drag, which reduces fuel efficiency in passenger airliners. It also increases the radar signature, which is something you want to keep as low as possible in a military aircraft.

In the B-2 stealth bomber, one of the very few rudderless airplanes, Dutch roll instabilities are dealt with using drag flaps positioned at the tips of its wings, which can split and open to make one wing generate more drag than the other and thus laterally stabilize the machine. “But it is not really an efficient way to solve this problem,” says David Lentink, an aerospace engineer and a biologist at the University of Groningen, Netherlands. “The efficient way is solving it by generating lift instead of drag. This is something birds do.”

Lentink led the study aimed at better understanding birds’ rudderless flight mechanics.

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© HamidEbrahimi

Tweaking non-neural brain cells can cause memories to fade

23 November 2024 at 12:00

“If we go back to the early 1900s, this is when the idea was first proposed that memories are physically stored in some location within the brain,” says Michael R. Williamson, a researcher at the Baylor College of Medicine in Houston. For a long time, neuroscientists thought that the storage of memory in the brain was the job of engrams, ensembles of neurons that activate during a learning event. But it turned out this wasn’t the whole picture.

Williamson’s research investigated the role astrocytes, non-neuron brain cells, play in the read-and-write operations that go on in our heads. “Over the last 20 years the role of astrocytes has been understood better. We’ve learned that they can activate neurons. The addition we have made to that is showing that there are subsets of astrocytes that are active and involved in storing specific memories,” Williamson says in describing a new study his lab has published.

One consequence of this finding: Astrocytes could be artificially manipulated to suppress or enhance a specific memory, leaving all other memories intact.

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© Ed Reschke

Our Universe is not fine-tuned for life, but it’s still kind of OK

22 November 2024 at 18:30

Physicists including Robert H. Dickle and Fred Hoyle have argued that we are living in a universe that is perfectly fine-tuned for life. Following the anthropic principle, they claimed that the only reason fundamental physical constants have the values we measure is because we wouldn’t exist if those values were any different. There would simply have been no one to measure them.

But now a team of British and Swiss astrophysicists have put that idea to test. “The short answer is no, we are not in the most likely of the universes,” said Daniele Sorini, an astrophysicist at Durham University. “And we are not in the most life-friendly universe, either.” Sorini led a study aimed at establishing how different amounts of the dark energy present in a universe would affect its ability to produce stars. Stars, he assumed, are a necessary condition for intelligent life to appear.

But worry not. While our Universe may not be the best for life, the team says it’s still pretty OK-ish.

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© Sololos

Bats use echolocation to make mental maps for navigation

1 November 2024 at 17:25

Many species of bats use echolocation to avoid obstacles like tree branches and hunt small insects as they fly through the dark. But it turns out echolocation for bats is much more than just a short-range obstacle-avoidance and prey-targeting system. A recent study shows that one species of bats can stitch together thousands upon thousands of sound signatures into acoustic maps they use to successfully navigate several kilometers over their hunting grounds. The maps work even if the bats are completely blindfolded.

Blindfolded bats

“What echolocating bats do is they emit sounds, ultrasonic or not, and use the characteristics of the reflected echo to sense objects they have in front of them. We wanted to know if they use it for large-scale navigation. Most people think, 'Of course they do,' but the reality is we didn’t know that,” says Aya Goldshtein, a researcher at the Max Planck Institute of Animal Behavior in Konstanz, Germany. Goldshtein collaborated with scientists at Tel Aviv University on a study of how a species of bats called Kuhl’s pipistrelle navigate in their natural environment.

There were several reasons that navigation via echolocation wasn’t obvious at all. For starters, echolocation is hopelessly limited when it comes to range. Bats can use it to sense objects that are at most a few dozen meters away. It’s a tool closer to an ultrasonic parking sensor in a car than to a long-distance sonar in a submarine. It is also not omnidirectional. The cone of coverage bats get from echolocation is usually a maximum of 120 degrees, although they can modulate it to an extent, depending on the shape of their mouths.

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© Ashley Cooper

Lidar mapping reveals mountainous medieval cities along the Silk Road

28 October 2024 at 22:16

The history of the Silk Road, a vast network of ancient and medieval trade routes connecting Beijing and Hangzhou with Constantinople and Cairo, has mostly been focused on its endpoints: China and the West. Less was known about the people and cultures the traders encountered along the way. Given the length of the route, there must have been a lot of encounters. Traders passed through large cities like Tehran or Baghdad, which we know very well because they still stand today. They also crossed the Tien Shan, the largest east-west mountain range on the planet.

“People thought these mountains were just places the caravans had to cross and get through but not really a major contributor to commerce themselves,” says Michael Frachetti, an anthropologist at Washington University in St. Louis, who led a team that used drone-based lidar to map two mountainous cities at the western end of Tien Shan in the modern-day Uzbekistan. Both were built over 2,000 meters above sea level like Machu Picchu or Lhasa, Tibet. One of them, the Tugunbulak, was larger than Siena, one of the most influential city-states in medieval Italy.

Into the mountains

“The Silk Road was a complicated complex representing in some cases actual pathways the caravans could traverse, but also general exchange between East Asia and Europe. If you ask me, as an archeologist, the foundations of Silk Road can be traced back to the Bronze Age. But the peak of this exchange we date to the medieval period, between the 6th century and the 11th century,” says Frachetti.

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© Feng Wei Photography

Google’s DeepMind is building an AI to keep us from hating each other

24 October 2024 at 23:36

An unprecedented 80 percent of Americans, according to a recent Gallup poll, think the country is deeply divided over its most important values ahead of the November elections. The general public’s polarization now encompasses issues like immigration, health care, identity politics, transgender rights, or whether we should support Ukraine. Fly across the Atlantic and you’ll see the same thing happening in the European Union and the UK.

To try to reverse this trend, Google’s DeepMind built an AI system designed to aid people in resolving conflicts. It’s called the Habermas Machine after Jürgen Habermas, a German philosopher who argued that an agreement in a public sphere can always be reached when rational people engage in discussions as equals, with mutual respect and perfect communication.

But is DeepMind’s Nobel Prize-winning ingenuity really enough to solve our political conflicts the same way they solved chess or StarCraft or predicting protein structures? Is it even the right tool?

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© Jose Luis Pelaez Inc

Desalination system adjusts itself to work with renewable power

18 October 2024 at 19:06

Fresh water we can use for drinking or agriculture is only about 3 percent of the global water supply, and nearly 70 percent of that is trapped in glaciers and ice caps. So far, that was enough to keep us going, but severe draughts have left places like Jordan, Egypt, sub-Saharan Africa, Spain, and California with limited access to potable water.

One possible solution is to tap into the remaining 97 percent of the water we have on Earth. The problem is that this water is saline, and we need to get the salt out of it to make it drinkable. Desalination is also an energy-expensive process. But MIT researchers led by Jonathan Bessette might have found an answer to that. They built an efficient, self-regulating water desalination system that runs on solar power alone with no need for batteries or a connection to the grid.

Probing the groundwaters

Oceans are the most obvious source of water for desalination. But they are a good option only for a small portion of people who live in coastal areas. Most of the global population—more or less 60 percent—lives farther than 100 kilometers from the coast, which makes using desalinated ocean water infeasible. So, Bessette and his team focused on groundwater instead.

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© Ismail BELLAOUALI

Injured comb jellies can fuse into a single organism

8 October 2024 at 16:38

Comb jellies, technically known as ctenophores, are one of the weirdest creatures on Earth. They appeared in the seas over half a billion years ago and have maintained to the present day the comb-like rows of cilia they used to move around. Their transparent bodies and internal bioluminescence give them looks that rival gaming computers. But there’s something that makes them even weirder.

When a comb jelly is injured, it can regenerate at an amazing rate. But it can also attach a body part of another injured comb jelly and integrate it near-seamlessly into its own body. (Those who have played Elden Ring can enjoy comparisons to Godrick The Grafted.)

“I’ve been observing ctenophores for a long time, so it was easy to spot an unusually large specimen. Some of the anatomical features were doubled, so I realized what I’m looking at is actually two individuals that have fused together,” said Kei Jokura, a marine researcher at the University of Exeter and lead author of a recent Current Biology paper on the integration of fused ctenophores.

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© Yiming Chen

The more sophisticated AI models get, the more likely they are to lie

4 October 2024 at 19:39

When a research team led by Amrit Kirpalani, a medical educator at Western University in Ontario, Canada, evaluated ChatGPT’s performance in diagnosing medical cases back in August 2024, one of the things that surprised them was the AI’s propensity to give well-structured, eloquent but blatantly wrong answers.

Now, in a study recently published in Nature, a different group of researchers tried to explain why ChatGPT and other large language models tend to do this. “To speak confidently about things we do not know is a problem of humanity in a lot of ways. And large language models are imitations of humans,” says Wout Schellaert, an AI researcher at the University of Valencia, Spain, and co-author of the paper.

Smooth operators

Early large language models like GPT-3 had a hard time answering simple questions about geography or science. They even struggled with performing simple math such as “how much is 20 +183.” But in most cases where they couldn’t identify the correct answer, they did what an honest human being would do: They avoided answering the question.

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© malerapaso

Robot placed under the control of a fungal overlord

19 September 2024 at 15:38
Robot placed under the control of a fungal overlord

Enlarge (credit: Aurich Lawson | Getty Images)

Most living organisms easily surpass machines when it comes to navigating real-world environments and adaptability to changing conditions. One way to bridge that gap is building biohybrid robots that merge synthetic machinery with biological components like animal muscles, bacteria, or plants.

But living muscles are very hard to keep alive in a machine, bacteria have a very short lifespan, and plants tend to react to things a bit slowly, like Ents in The Lord of the Rings. So, a team of scientists at Cornell University went down a different path and built biohybrid robots controlled by fungi, specifically, oyster mushrooms.

Understanding mushrooms’ signals

Robots controlled by fungi, despite giving strong Last of Us vibes, are a good idea on paper. Fungi are very easy to sustain and can live pretty much everywhere, including extreme environments like the Arctic, or even amid nuclear contamination. They're also cheap to culture in large quantities and excel at reacting to environmental cues like exposure to light.

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Mice made transparent with a dye used in Doritos

16 September 2024 at 16:58
Zihao Ou, who helped develop this solution, holds a tube of it.

Enlarge / Zihao Ou, who helped develop this solution, holds a tube of it.

One key challenge in medical imaging is to look past skin and other tissue that are opaque to see internal organs and structures. This is the reason we need things like ultrasonography, magnetic resonance, or X-rays. There are chemical clearing agents that can make tissue transparent, like acrylamide or tetrahydrofuran, but they are almost never used in living organisms because they’re either highly toxic or can dissolve away essential biomolecules.

But now, a team of Stanford University scientists has finally found an agent that can reversibly make skin transparent without damaging it. This agent was tartrazine, a popular yellow-orange food dye called FD&C Yellow 5 that is notably used for coloring Doritos.

Playing with light

We can’t see through the skin because it is a complex tissue comprising aqueous-based components such as cell interiors and other fluids, as well as protein and lipids. The refractive index is a value that indicates how much light slows down (on average, of course) while going through a material compared to going through a vacuum. The refractive index of those aqueous components is low, while the refractive index of the proteins and lipids is high. As a result, light traveling through skin constantly bends as it endlessly crosses the boundary between high and low refractive index materials.

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Remembering where your meals came from key for a small bird’s survival

13 September 2024 at 13:07
a small, black and grey bird perched on the branch of a fir tree.

Enlarge (credit: BirdImages)

It seems like common sense that being smart should increase the chances of survival in wild animals. Yet for a long time, scientists couldn’t demonstrate that because it was unclear how to tell exactly if a lion or a crocodile or a mountain chickadee was actually smart or not. Our best shots, so far, were looking at indirect metrics like brain size or doing lab tests of various cognitive skills such as reversal learning, an ability that can help an animal adapt to a changing environment.

But a new, large-scale study on wild mountain chickadees, led by Joseph Welklin, an evolutionary biologist at the University of Nevada, showed that neither brain size nor reversal learning skills were correlated with survival. What mattered most for chickadees, small birds that save stashes of food, was simply remembering where they cached all their food. A chickadee didn’t need to be a genius to survive; it just needed to be good at its job.

Testing bird brains

“Chickadees cache one food item in one location, and they do this across a big area. They can have tens of thousands of caches. They do this in the fall and then, in the winter, they use a special kind of spatial memory to find those caches and retrieve the food. They are little birds, weight is like 12 grams, and they need to eat almost all the time. If they don’t eat for a few hours, they die,” explains Vladimir Pravosudov, an ornithologist at the University of Nevada and senior co-author of the study.

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More water worlds than we thought might support life

5 September 2024 at 16:23
Diagram of Earth and an exoplanet, showing that the water-covered exoplanet would form a layer of high-pressure ices.

Enlarge / High pressure ices near the crust are a feature of water-rich worlds.` (credit: Benoit Gougeon (University of Montreal))

The possibility that there is liquid water on an exoplanet’s surface usually flags it as “potentially habitable,” but the reality is that too much water might prevent life from taking hold.

“On Earth, the ocean is in contact with some rock. If we have too much water, it creates high-pressure ice underneath the ocean, which separates it from the planet’s rocky interior,” said Caroline Dorn, a geophysicist at ETH Zurich, Switzerland, who led new research in exoplanet interiors.

This high-pressure ice prevents minerals and chemical compounds from being exchanged between the rocks and the water. In theory, that should make the ocean barren and lifeless. But Dorn’s team argues that even exoplanets that have enough water to form such high-pressure ice can host life if the majority of the water is not stored in the surface oceans but is held much deeper in the planet’s core. The water in the core can’t sustain life—it’s not even in its molecular form there. But it means that a substantial fraction of a planet’s water isn’t on the surface, which makes the surface oceans a little more shallow and prevents high-pressure ice from forming at their bottom.

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Passing part of a medical licensing exam doesn’t make ChatGPT a good doctor

16 August 2024 at 14:43
Smiling doctor discussing medical results with a woman.

Enlarge / For now, "you should see a doctor" remains good advice.

ChatGPT was able to pass some of the United States Medical Licensing Exam (USMLE) tests in a study done in 2022. This year, a team of Canadian medical professionals checked to see if it’s any good at actual doctoring. And it’s not.

ChatGPT vs. Medscape

“Our source for medical questions was the Medscape questions bank,” said Amrit Kirpalani, a medical educator at the Western University in Ontario, Canada, who led the new research into ChatGPT’s performance as a diagnostic tool. The USMLE contained mostly multiple-choice test questions; Medscape has full medical cases based on real-world patients, complete with physical examination findings, laboratory test results, and so on.

The idea behind it is to make those cases challenging for medical practitioners due to complications like multiple comorbidities, where two or more diseases are present at the same time, and various diagnostic dilemmas that make the correct answers less obvious. Kirpalani’s team turned 150 of those Medscape cases into prompts that ChatGPT could understand and process.

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“Archeology” on the ISS helps identify what astronauts really need

9 August 2024 at 17:10
I woman holds a handheld device in front of a rack of equipment.

Enlarge / Jessica Watkins gets to work on the ISS (credit: NASA)

“Archeology really is a perspective on material culture we use as evidence to understand how humans adapt to their environment, to the situations they are in, and to each other. There is no place, no time that is out of bounds,” says Justin Walsh, an archeologist at Chapman University who led the first off-world archeological study on board the ISS.

Walsh’s and his team wanted to understand, document, and preserve the heritage of the astronaut culture at one of the first permanent space habitats. “There is this notion about astronauts that they are high achievers, highly intelligent, and highly trained, that they are not like you and me. What we learned is that they are just people, and they want the comforts of home,” Walsh says.

Disposable cameras and garbage

“In 2008, my student in an archeology class raised her hand and said, ‘What about stuff in space, is that heritage?’ I said, ‘Oh my God, I’ve never thought of this before, but yes,’” Walsh says. “Think of Tranquility base—it’s an archeological site. You could go back there, and you could reconstruct not only the specific activities of Neil Armstrong and Buzz Aldrin, but you could understand the engineering culture, the political culture, etc. of the society that created that equipment, sent it to the Moon, and left it there.”

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