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Today — 21 February 2025Main stream

Why Houston’s 2024 derecho did more damage than hurricane Beryl

21 February 2025 at 20:32

On May 16, 2024, a powerful derecho swept through Houston, killing seven people and causing significant damage to several of the city's towering skyscrapers. Those buildings were constructed to withstand much stronger hurricane-force winds up to 67 meters per second, as one would get with a Category 4 hurricane. The derecho's winds peaked at 40 meters per second, well below that threshold. And when Hurricane Beryl hit Houston that July with roughly comparable wind speeds of 36 meters per second, the damage wasn't nearly so severe. Why would that be the case?

Engineers at Florida International University (FIU) in Miami think they've found the answer, according to a new paper published in the journal Frontiers in Built Environment. "We show that a type of highly localized strong winds called ‘downbursts,’ which were generated during the May derecho, can significantly impact tall buildings and facades due to their unique characteristics in comparison to hurricanes,” said co-author Amal Elawady. This is particularly the case for skyscrapers that are close together, creating a "wind-channeling" interference effect that increases pressure on walls and windows.

One might assume that hurricanes and derechos are similar in that they both produce markedly intense winds, but the origin and characteristics of those winds are very different, per the authors. Hurricanes are vast tropical storms that form over warm ocean waters and affect large areas, usually lasting for several days, accompanied by heavy rains, storm surges, waves, and yes, high winds. By contrast, derechos and downbursts are much more localized convective systems, producing hurricane-force winds but over a much smaller area and shorter period of time.

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© National Weather Service/Public Domain

Yesterday — 20 February 2025Main stream

Study: Cuttlefish adapt camouflage displays when hunting prey

20 February 2025 at 20:41

Crafty cuttlefish employ several different camouflaging displays while hunting their prey, according to a new paper published in the journal Ecology, including mimicking benign ocean objects like a leaf or coral, or flashing dark stripes down their bodies. And individual cuttlefish seem to choose different preferred hunting displays for different environments.

It's well-known that cuttlefish and several other cephalopods can rapidly shift the colors in their skin thanks to that skin's unique structure. As previously reported, squid skin is translucent and features an outer layer of pigment cells called chromatophores that control light absorption. Each chromatophore is attached to muscle fibers that line the skin's surface, and those fibers, in turn, are connected to a nerve fiber. It's a simple matter to stimulate those nerves with electrical pulses, causing the muscles to contract. And because the muscles are pulling in different directions, the cell expands, along with the pigmented areas, changing the color. When the cell shrinks, so do the pigmented areas.

Underneath the chromatophores, there is a separate layer of iridophores. Unlike the chromatophores, the iridophores aren't pigment-based but are an example of structural color, similar to the crystals in the wings of a butterfly, except a squid's iridophores are dynamic rather than static. They can be tuned to reflect different wavelengths of light. A 2012 paper suggested that this dynamically tunable structural color of the iridophores is linked to a neurotransmitter called acetylcholine. The two layers work together to generate the unique optical properties of squid skin.

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© Matteo Santon/University of Bristol

Before yesterdayMain stream

Scientists unlock vital clue to strange quirk of static electricity

19 February 2025 at 19:47
Scientists can now explain the prevailing unpredictability of contact electrification, unveiling order from what has long been considered chaos.

Static electricity—specifically the triboelectric effect, aka contact electrification—is ubiquitous in our daily lives, found in such things as a balloon rubbed against one's hair or styrofoam packing peanuts sticking to a cat's fur (as well as human skin, glass tabletops, and just about anywhere you don't want packing peanuts to be). The most basic physics is well understood, but long-standing mysteries remain, most notably how different materials exchange positive and negative charges—sometimes ordering themselves into a predictable series, but sometimes appearing completely random.

Now scientists at the Institute of Science and Technology Austria (ISTA) have identified a critical factor explaining that inherent unpredictability: It's the contact history of given materials that controls how they exchange charges in contact electrification. They described their findings in a new paper published in the journal Nature.

Johan Carl Wilcke published the first so-called "triboelectric series" in 1757 to describe the tendency of different materials to self-order based on how they develop a positive or negative charge. A material toward the bottom of the list, like hair, will acquire a more negative charge when it comes into contact with a material near the top of the list, like a rubber balloon.

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© YouTube/Institute of Science and Technology Austria

3D map of exoplanet atmosphere shows wacky climate

18 February 2025 at 19:04

Astronomers have detected over 5,800 confirmed exoplanets. One extreme class is ultra-hot Jupiters, of particular interest because they can provide a unique window into planetary atmospheric dynamics. According to a new paper published in the journal Nature, astronomers have mapped the 3D structure of the layered atmosphere of one such ultra-hot Jupiter-size exoplanet, revealing powerful winds that create intricate weather patterns across that atmosphere. A companion paper published in the journal Astronomy and Astrophysics reported on the unexpected identification of titanium in the exoplanet's atmosphere as well.

As previously reported, thanks to the massive trove of exoplanets discovered by the Kepler mission, we now have a good idea of what kinds of planets are out there, where they orbit, and how common the different types are. What we lack is a good sense of what that implies in terms of the conditions on the planets themselves. Kepler can tell us how big a planet is, but it doesn't know what the planet is made of. And planets in the "habitable zone" around stars could be consistent with anything from a blazing hell to a frozen rock.

Like the Transiting Exoplanet Survey Satellite (TESS), Kepler identifies planets using the transit method. This works for systems in which the planets orbit in a plane that takes them between their host star and Earth. As this occurs, the planet blocks a small fraction of the starlight that we see from Earth (or nearby orbits). If these dips in light occur with regularity, they're diagnostic of something orbiting the star.

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© ESO/M. Kornmesser

Scientists found a faster way to brew sour beer—with peas

5 February 2025 at 13:00

Do you long for that tart fruity flavor of a sour beer but wish the complicated brewing process were faster? Norwegian scientists might have the answer: field peas, as well as beans and lentils. According to a new paper published in the Journal of Agricultural and Food Chemistry, experimental beers made with the sugars found in these foods had similar flavor profiles to your average Belgian-style sour beer, yet the brewing process was shorter with simpler steps.

“Sour beer is the beer enthusiast’s alternative to champagne," said co-author Bjørge Westereng of the Norwegian University of Life Science. "By using sugars derived from peas that yeast cannot metabolize, we promote the growth of bacteria essential for producing sour beer.”

As previously reported, sour beer has been around for centuries and has become a favorite with craft brewers in recent years, although the brewing process can be both unpredictable and time-consuming. Brewers of standard beer carefully control the strains of yeast they use, taking care to ensure other microbes don't sneak into the mix, lest they alter the flavor during fermentation.

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© MediaNews Group/Bay Area News via Getty Images

Gecko feet inspire anti-slip shoe soles

4 February 2025 at 16:07

Gecko feet have inspired many intriguing applications, including a sticky tape, adhesives, a "stickybot" climbing robot, and even a strapless bra design. Now, scientists have developed a new kind of anti-slip polymer that sticks to ice, inspired by the humble gecko. Incorporating these polymers into shoe soles could reduce the number of human slip-and-fall injuries, according to a paper published in the journal ACS Applied Materials & Interfaces.

As previously reported, geckos are known for being expert climbers; they're able to stick to any surface thanks to tiny hair-like structures on the bottoms of their feet. Those microscopic hairs are called setae, each of which splits off into hundreds of even smaller bristles called spatulae. It has long been known that at microscopic size scales, the so-called van der Waals forces—the attractive and repulsive forces between two dipole molecules—become significant.

Essentially, the tufts of tiny hairs on gecko feet get so close to the contours in walls and ceilings that electrons from the gecko hair molecules and electrons from the wall molecules interact with each other and create an electromagnetic attraction. That's what enables geckos to climb smooth surfaces like glass effortlessly. Spiders, cockroaches, beetles, bats, tree frogs, and lizards all have varying-sized sticky footpads that use these same forces.

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© Yi Song

Let us spray: River dolphins launch pee streams into air

3 February 2025 at 20:14

According to Amazonian folklore, the area's male river dolphins are shapeshifters (encantade), transforming at night into handsome young men who seduce and impregnate human women. The legend's origins may lie in the fact that dolphins have rather human-like genitalia. A group of Canadian biologists didn't spot any suspicious shapeshifting behavior over the four years they spent monitoring a dolphin population in central Brazil, but they did document 36 cases of another human-like behavior: what appears to be some sort of cetacean pissing contest.

Specifically, the male dolphins rolled over onto their backs, displayed their male members, and launched a stream of urine as high as 3 feet into the air. This usually occurred when other males were around, who seemed fascinated in turn by the arching streams of pee, even chasing after them with their snouts. It's possibly a form of chemical sensory communication and not merely a need to relieve themselves, according to the biologists, who described their findings in a paper published in the journal Behavioral Processes. As co-author Claryana Araújo-Wang of CetAsia Research Group in Ontario, Canada, told New Scientist, “We were really shocked, as it was something we had never seen before.”

Spraying urine is a common behavior in many animal species, used to mark territory, defend against predators, communicate with other members of one's species, or as a means of mate selection since it has been suggested that the chemicals in the urine carry useful information about physical health or social dominance.

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© Claryana Araújo-Wang / Botos do Cerrado Research Project / CetAsia Research Group

Research Roundup: 7 cool science stories we almost missed

31 January 2025 at 12:30

It's a regrettable reality that there is never time to cover all the interesting scientific stories each month. In the past, we've featured year-end roundups of cool science stories we missed. This year, we're experimenting with a monthly collection. January's list includes papers on using lasers to reveal Peruvian mummy tattoos; the physics of wobbly spears and darts; how a black hole changes over time; and quantum "cat states" for error correction in quantum computers, among other fascinating research.

Tracking changes in a black hole over time

Left: EHT images of M87* from the 2018 and 2017 observation campaigns. Middle: Example images from a general relativistic magnetohydrodynamic (GRMHD) simulation at two different times. Right: Same simulation snapshots, blurred to match the EHT's observational resolution. Credit: EHT collaboration

In 2019, the Event Horizon Telescope announced the first direct image ever taken of a black hole at the center of an elliptical galaxy, Messier 87 (M87), located in the constellation of Virgo some 55 million light-years away. Astronomers have now combined earlier observational data to learn more about the turbulent dynamics of plasma near M87*'s event horizon over time, according to a paper published in the journal Astronomy and Astrophysics.

Co-author Luciano Rezzolla of Goethe University Frankfurt in Germany likened the new analysis to comparing two photographs of Mount Everest, one year apart. While the mountain's basic structure is unlikely to change much in that time, one could observe changes in clouds near the peak and deduce from that properties like wind direction. For instance, in the case of M87*, the new analysis confirmed the presence of a luminous ring that is brightest at the bottom, which in turn confirmed that the rotational axis points away from Earth. "More of these observations will be made in the coming years and with increasing precision, with the ultimate goal of producing a movie of what happens near M87*," said Rezolla.

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© Michael Pittman and Thomas G Kaye

This mantis shrimp-inspired robotic arm can crack an egg

29 January 2025 at 19:00
An egg-cracking beam relies on a hyperelastic torque reversal mechanism similar to that used by mantis shrimp and jumping fleas. Credit: Seoul National University.

We usually think of robots as being made out of hard, rigid materials, but soft robotics seeks to build robotic devices out of more flexible materials that mimic the properties of those found in living animals. Case in point: Korean engineers have built soft robots capable of rapid and powerful joint movements by employing the same mechanism that gives the mantis shrimp such a powerful punch, according to a new paper published in the journal Science Robotics.

As we've reported previously, mantis shrimp come in many different varieties; there are some 450 known species. But they can generally be grouped into two types: those that stab their prey with spear-like appendages ("spearers") and those that smash their prey ("smashers") with large, rounded, and hammer-like claws ("raptorial appendages"). Those strikes are so fast (as much as 23 meters per second, or 51 mph) and powerful, they often produce cavitation bubbles in the water, creating a shock wave that can serve as a follow-up strike, stunning and sometimes killing the prey. Sometimes a strike can even produce sonoluminescence, whereby the cavitation bubbles produce a brief flash of light as they collapse.

According to a 2018 study, the secret to that powerful punch seems to arise not from bulky muscles but from the spring-loaded anatomical structure of the shrimp's arms, akin to a bow and arrow or a mousetrap. The shrimp's muscles pull on a saddle-shaped structure in the arm, causing it to bend and store potential energy, which is released with the swinging of the club-like claw. It's essentially a latch-like mechanism (technically, Latch-mediated spring actuation, or LaMSA), with small structures in the muscle tendons called sclerites serving as the latch.

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© Seoul National University

A telltale toilet reveals “lost” site shown in Bayeux Tapestry

28 January 2025 at 18:56

The Bayeux Tapestry famously depicts the events leading up to the 1066 Norman Conquest of England, in which William the Conqueror defeated Harold II, the last Anglo-Saxon king of England, at the Battle of Hastings. Two scenes in particular show King Harold feasting in an extravagant hall in a village called Bosham. Archaeologists think they have now located the site of that feast, concluding that it was the king's own home, according to a new paper published in The Antiquaries Journal.

“The Norman Conquest saw a new ruling class supplant an English aristocracy that has left little in the way of physical remains, which makes the discovery at Bosham hugely significant," said co-author Oliver Creighton of the University of Exeter. "We have found an Anglo-Saxon show-home.” The findings are part of an ongoing project called "Where Power Lies," intended to assess archaeological evidence for aristocratic centers across England from the pre-Norman period.

Scholars believe the Bayeux Tapestry dates back to the 11th century and was likely created just a few years after the Battle of Hastings, mostly likely commissioned by Bishop Odo of Bayeux (although there is still considerable debate over alternative theories). It's technically not a tapestry, since it's not woven but embroidered on linen using wool yarn of various colors. There are 58 individual scenes spanning 230 feet (nearly 70 meters) in length and 20 inches (50 cm) in height. Latin text provides context for the imagery. Among the historical events depicted is the appearance of what is now known as Halley's Comet, used here as a harbinger of the coming Norman invasion.

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© The Society of Antiquaries of London

Complexity physics finds crucial tipping points in chess games

24 January 2025 at 18:02

The game of chess has long been central to computer science and AI-related research, most notably in IBM's Deep Blue in the 1990s and, more recently, AlphaZero. But the game is about more than algorithms, according to Marc Barthelemy, a physicist at the Paris-Saclay University in France, with layers of depth arising from the psychological complexity conferred by player strategies.

Now, Barthelmey has taken things one step further by publishing a new paper in the journal Physical Review E that treats chess as a complex system, producing a handy metric that can help predict the proverbial "tipping points" in chess matches.

In his paper, Barthelemy cites Richard Reti, an early 20th-century chess master who gave a series of lectures in the 1920s on developing a scientific understanding of chess. It was an ambitious program involving collecting empirical data, constructing typologies, and devising laws based on those typologies, but Reti's insights fell by the wayside as advances in computer science came to dominate the field. That's understandable. "With its simple rules yet vast strategic depth, chess provides an ideal platform for developing and testing algorithms in AI, machine learning, and decision theory," Barthelemy writes.

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© Jean-Henri Marlet/Public domain

George R.R. Martin has co-authored a physics paper

23 January 2025 at 16:22

Although fans of A Song of Ice and Fire might still be hankering for the long-delayed next book in the series, bestselling sci-fi/fantasy author George R.R. Martin has instead added a different item to his long list of publications: a peer-reviewed physics paper just published in the American Journal of Physics that he co-authored. The paper derives a formula to describe the dynamics of a fictional virus that is the centerpiece of the Wild Cards series of books, a shared universe edited by Martin and Melinda M. Snodgrass, with some 44 authors contributing.

Wild Cards grew out of the Superworld RPG, specifically a long-running campaign game-mastered by Martin in the 1980s, with several of the original sci-fi writers who contributed to the series participating. (A then-unknown Neil Gaiman once pitched Martin a Wild Cards story involving a main character who lived in a world of dreams. Martin rejected the pitch, and Gaiman's idea became The Sandman.) Initially, Martin planned to write a novel centered on his character Turtle, but he then decided it would be better as a shared universe anthology. Martin thought that superhero comics had far too many sources of the many different superpowers and wanted his universe to have one single source. Snodgrass suggested a virus.

The series is basically an alternate history of the US in the aftermath of World War II. An airborne alien virus, designed to rewrite DNA, had been released over New York City in 1946 and spread globally, infecting tens of thousands worldwide. It's called the Wild Card virus because it affects every individual differently. It kills 90 percent of those it infects and mutates the rest. Nine percent of the latter end up with unpleasant conditions—these people are called Jokers—while 1 percent develop superpowers and are known as Aces. Some Aces have "powers" that are so trivial and useless that they are known as "deuces."

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© Michael Kormarck/Tor Books

Fast radio burst in long-dead galaxy puzzles astronomers

22 January 2025 at 18:06

Fast radio bursts (FRBs) are puzzling phenomena because their details are so difficult to resolve, and observations to date have been inconsistent. Astronomers added another piece to the puzzle with the detection of an FRB that seems to originate in a dead galaxy that is no longer producing new stars, according to a new paper published in The Astrophysical Journal Letters, along with a related paper on the event from scientists at Northwestern University.

As we've reported previously, FRBs involve a sudden blast of radio-frequency radiation that lasts just a few microseconds. Astronomers have observed over a thousand of them to date; some come from sources that repeatedly emit FRBs, while others seem to burst once and go silent. You can produce this sort of sudden surge of energy by destroying something. But the existence of repeating sources suggests that at least some of them are produced by an object that survives the event. That has led to a focus on compact objects, like neutron stars and black holes—especially a class of neutron stars called magnetars—as likely sources. Only about 3 percent of FRBs are of the repeating variety.

There have also been many detected FRBs that don't seem to repeat at all, suggesting that the conditions that produce them may destroy their source. That's consistent with a blitzar—a bizarre astronomical event caused by the sudden collapse of an overly massive neutron star. The event is driven by an earlier merger of two neutron stars; this creates an unstable intermediate neutron star, which is kept from collapsing immediately by its rapid spin.

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© Gemini Observatory

How to get a perfect salt ring deposit in your pasta pot

21 January 2025 at 17:41

Physicist Mathieu Souzy of the University Twente was enjoying an evening of pasta and board games with several colleagues when the conversation turned to how adding salt to a pasta pot to make it boil faster can leave a white ring on the bottom of the pot. Ever the curious scientists, they wondered about the various factors that would contribute to creating the perfect circular pattern for a salt ring.

“By the end of our meal, we’d sketched an experimental protocol and written a succession of experiments we wanted to try on my youngest son’s small whiteboard,” said Souzy. It all comes down to three factors: the diameter of the particles (grains of salt, in this case), the settling height, and the number of particles released simultaneously, according to a new paper published in the journal Physics of Fluids.

We've previously reported on physicists' longstanding interest in similar phenomena like the "coffee ring effect," when a single liquid evaporates and the solids that had been dissolved in the liquid (like coffee grounds) form a ring. It happens because the evaporation occurs faster at the edge than at the center. Any remaining liquid flows outward to the edge to fill in the gaps, dragging those solids with it. Mixing in solvents (water or alcohol) reduces the effect as long as the drops are very small. Large drops produce more uniform stains.

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© Mathieu Souzy

Robotic hand helps pianists overcome “ceiling effect”

20 January 2025 at 19:35
Fast and complex multi-finger movements generated by the hand exoskeleton. Credit: Shinichi Furuya

When it comes to fine-tuned motor skills like playing the piano, practice, they say, makes perfect. But expert musicians often experience a "ceiling effect," in which their skill level plateaus after extensive training. Passive training using a robotic exoskeleton hand could help pianists overcome that ceiling effect, according to a paper published in the journal Science Robotics.

“I’m a pianist, but I [injured] my hand because of overpracticing,” coauthor Shinichi Furuya of Kabushiki Keisha Sony Computer Science Kenkyujo told New Scientist. “I was suffering from this dilemma, between overpracticing and the prevention of the injury, so then I thought, I have to think about some way to improve my skills without practicing.” Recalling that his former teachers used to place their hands over his to show him how to play more advanced pieces, he wondered if he could achieve the same effect with a robotic hand.

So Furuya et al. used a custom-made exoskeleton robot hand capable of moving individual fingers on the right hand independently, flexing and extending the joints as needed. Per the authors, prior studies with robotic exoskeletons focused on simpler movements, such as assisting in the movement of limbs stabilizing body posture, or helping grasp objects. That sets the custom robotic hand used in these latest experiments apart from those used for haptics in virtual environments.

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© Shinichi Furuya

Peeing is contagious among chimps

20 January 2025 at 16:00

When ya gotta go, ya gotta go, and if it sometimes seems like the urge to pee seems more pressing when others nearby are letting loose—well, there's now a bit of science to back that up. It turns out that humans may not be the only species to experience "contagious urination," according to a new paper published in the journal Current Biology. Chimpanzees living at the Kumamoto Sanctuary in Japan are also more likely to relieve themselves when others are doing so nearby, and the behavior seems to be hierarchical, "flowing down" from dominant chimps to more passive ones.

“In humans, urinating together can be seen as a social phenomenon,” said coauthor Ena Onishi of Kyoto University. “An Italian proverb states, ‘Whoever doesn’t pee in company is either a thief or a spy’ (Chi non piscia in compagnia o è un ladro o è una spia), while in Japanese, the act of urinating with others is referred to as 'Tsureshon' (連れション). This behavior is represented in art across centuries and cultures and continues to appear in modern social contexts. Our research suggests that this phenomenon may have deep evolutionary roots.”

Onishi, et al decided to study the phenomenon after noticing that many chimps in the sanctuary seemed to synchronize when they peed, and they wondered whether the phenomenon might be similar to how one person yawning can trigger others to follow suit—another "semi-voluntary physiological behavior." There had been no prior research into contagious peeing. So they filmed the 20 captive chimps over 600 hours, documenting over 1,300 "urination events."

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© Onishi et al., 2025/CC BY-SA

Heroes, villains, and childhood trauma in the MCEU and DCU

16 January 2025 at 19:09

Are superheroes and supervillains the product of their childhood experiences? Not if they belong to the Marvel Cinematic Extended Universe or DC Universe, according to a new paper published in the journal PLoS ONE. Canadian researchers watched many hours of those movies and looked at which characters suffered considerable childhood trauma. They concluded that those traumatic experiences were not significant factors in whether those characters turned out to be heroes or villains.

Prior studies have looked at the portrayal of trauma in superheroes, most notably the murder of Batman's parents and Spider-Man's uncle, as well as the destruction of Superman's home planet, Krypton. There has also been research on children sustaining injuries while pretending to be superheroes, as well as on the potential for superhero themes to help children overcome trauma and build self-esteem.

According to co-author Jennifer Jackson of the University of Calgary in Canada, two nursing students (since graduated) came up with the idea during a lab meeting to look at adverse childhood experiences and superheroes. It might seem a bit frivolous as a topic, but Jackson pointed out that Marvel and DC films reach audiences of hundreds of millions of people worldwide. "We also know that things we see in films and other media affects life in the real world," she said. "This influence could be used as a positive factor when supporting children's mental health and wellbeing. There may be shame or fear associated with some of the ACEs, and superheroes may be an effective ice breaker when broaching some difficult topics."

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© Warner Bros,

Up close and personal with the stag beetle in A Real Bug’s Life S2

14 January 2025 at 18:43

A plucky male American stag beetle thinks he's found a mate on a rotting old tree stump—and then realizes there's another male eager to make the same conquest. The two beetles face off in battle, until the first manages to get enough leverage to toss his romantic rival off the stump in a deft display of insect jujitsu. It's the first time this mating behavior has been captured on film, and the stag beetle is just one of the many fascinating insects featured in the second season of A Real Bug's Life, a National Geographic docuseries narrated by Awkwafina.

The genesis for the docuseries lies in a past rumored sequel to Pixar's 1998 animated film A Bug's Life, which celebrated its 25th anniversary two years ago. That inspired producer Bill Markham, among others, to pitch a documentary series on a real bug's life to National Geographic. "It was the quickest commission ever," Markham told Ars last year. "It was such a good idea, to film bugs in an entertaining family way with Pixar sensibilities." And thanks to the advent of new technologies—photogrammetry, probe and microscope lenses, racing drones, ultra-high-speed camera—plus a handful of skilled "bug wranglers," the team was able to capture the bug's-eye view of the world beautifully.

As with the Pixar film, the bugs (and adjacent creatures) are the main characters here, from cockroaches, monarch butterflies, and praying mantises to bees, spiders, and even hermit crabs. The 10 episodes, across two seasons, tell their stories as they struggle to survive in their respective habitats, capturing entire ecosystems in the process: city streets, a farm, the rainforest, a Texas backyard, and the African savannah, for example. Highlights from S1 included the first footage of cockroach egg casings hatching; wrangling army ants on location in a Costa Rica rainforest; and the harrowing adventures of a tiny jumping spider navigating the mean streets of New York City.

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© National Geographic/Darlyne A. Murawski

Skull long thought to be Cleopatra’s sister’s was actually a young boy

13 January 2025 at 19:19

Scientists have demonstrated that an ancient human skull excavated from a tomb at Ephesos was not that of Arsinoë IV, half-sister to Cleopatra VII. Rather, it's the skull of a young male between the ages of 11 and 14 from Italy or Sardinia, who may have suffered from one or more developmental disorders, according to a new paper published in the journal Scientific Reports. Arsinoë IV's remains are thus still missing.

Arsinoë IV led quite an adventurous short life. She was either the third or fourth daughter of Ptolemy XII, who left the throne to Cleopatra and his son, Ptolemy XIII, to rule together. Ptolemy XIII didn't care for this decision and dethroned Cleopatra in a civil war—until Julius Caesar intervened to enforce their father's original plan of co-rulership. As for Arsinoë, Caesar returned Cyprus to Egyptian rule and named her and her youngest brother (Ptolemy XIV) co-rulers. This time, it was Arsinoë who rebelled, taking command of the Egyptian army and declaring herself queen.

She was fairly successful at first in battling the Romans, conducting a siege against Alexandria and Cleopatra, until her disillusioned officers decided they'd had enough and secretly negotiated with Caesar to turn her over to him. Caesar agreed, and after a bit of public humiliation, he granted Arsinoë sanctuary in the temple of Artemis in Ephesus. She lived in relative peace for a few years, until Cleopatra and Mark Antony ordered her execution on the steps of the temple—a scandalous violation of the temple as a place of sanctuary. Historians disagree about Arsinoë's age when she died: Estimates range from 22 to 27.

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© Gerhard Weber, University of Vienna/CC BY

Did Hilma af Klint draw inspiration from 19th century physics?

11 January 2025 at 11:45

In 2019, astronomer Britt Lundgren of the University of North Carolina Asheville visited the Guggenheim Museum in New York City to take in an exhibit of the works of Swedish painter Hilma af Klint. Lundgren noted a striking similarity between the abstract geometric shapes in af Klint's work and scientific diagrams in 19th century physicist Thomas Young's Lectures (1807). So began a four-year journey starting at the intersection of science and art that has culminated in a forthcoming paper in the journal Leonardo, making the case for the connection.

Af Klint was formally trained at the Royal Academy of Fine Arts and initially focused on drawing, portraits, botanical drawings, and landscapes from her Stockholm studio after graduating with honors. This provided her with income, but her true life's work drew on af Klint's interest in spiritualism and mysticism. She was one of "The Five," a group of Swedish women artists who shared those interests. They regularly organized seances and were admirers of theosophical teachings of the time.

It was through her work with The Five that af Klint began experimenting with automatic drawing, driving her to invent her own geometric visual language to conceptualize the invisible forces she believed influenced our world. She painted her first abstract series in 1906 at age 44. Yet she rarely exhibited this work because she believed the art world at the time wasn't ready to appreciate it. Her will requested that the paintings stay hidden for at least 20 years after her death.

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© Hilma af Klimt Foundation

Why solving crosswords is like a phase transition

9 January 2025 at 19:55

Most crossword puzzle fans have experienced that moment where, after a period of struggle on a particularly difficult puzzle, everything suddenly starts to come together, and they are able to fill in a bunch of squares correctly. Alexander Hartmann, a statistical physicist at the University of Oldenburg in Germany, had an intriguing insight when this happened while he was trying to solve a puzzle one day. According to his paper published in the journal Physical Review E, the crossword puzzle-solving process resembles a type of phase transition known as percolation—one that seems to be unique compared to standard percolation models.

Traditional mathematical models of percolation date back to the 1940s. Directed percolation is when the flow occurs in a specific direction, akin to how water moves through freshly ground coffee beans, flowing down in the direction of gravity. (In physical systems, percolation is one of the primary mechanisms behind the Brazil nut effect, along with convection.) Such models can also be applicable to a wide range of large networked systems: power grids, financial markets, and social networks, for example.

Individual nodes in a random network start linking together, one by one, via short-range connections, until the number of connections reaches a critical threshold (tipping point). At that point, there is a phase shift in which the largest cluster of nodes grows rapidly, giving rise to more long-range connections, resulting in uber-connectivity. The likelihood of two clusters merging is proportional to their size, and once a large cluster forms, it dominates the networked system, absorbing smaller clusters.

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© Rhododendrites/CC BY-SA 4.0

Ants vs. humans: Solving the piano-mover puzzle

7 January 2025 at 19:20
Who is better at maneuvering a large load through a maze, ants or humans?

The piano-mover puzzle involves trying to transport an oddly shaped load across a constricted environment with various obstructions. It's one of several variations on classic computational motion-planning problems, a key element in numerous robotics applications. But what would happen if you pitted human beings against ants in a competition to solve the piano-mover puzzle?

According to a paper published in the Proceedings of the National Academy of Sciences, humans have superior cognitive abilities and, hence, would be expected to outperform the ants. However, depriving people of verbal or nonverbal communication can level the playing field, with ants performing better in some trials. And while ants improved their cognitive performance when acting collectively as a group, the same did not hold true for humans.

Co-author Ofer Feinerman of the Weizmann Institute of Science and colleagues saw an opportunity to use the piano-mover puzzle to shed light on group decision-making, as well as the question of whether it is better to cooperate as a group or maintain individuality. "It allows us to compare problem-solving skills and performances across group sizes and down to a single individual and also enables a comparison of collective problem-solving across species," the authors wrote.

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Delve into the physics of the Hula-Hoop

3 January 2025 at 18:11
High-speed video of experiments on a robotic hula hooper, whose hourglass form holds the hoop up and in place.

Some version of the Hula-Hoop has been around for millennia, but the popular plastic version was introduced by Wham-O in the 1950s and quickly became a fad. Now, researchers have taken a closer look at the underlying physics of the toy, revealing that certain body types are better at keeping the spinning hoops elevated than others, according to a new paper published in the Proceedings of the National Academy of Sciences.

“We were surprised that an activity as popular, fun, and healthy as hula hooping wasn’t understood even at a basic physics level,” said co-author Leif Ristroph of New York University. “As we made progress on the research, we realized that the math and physics involved are very subtle, and the knowledge gained could be useful in inspiring engineering innovations, harvesting energy from vibrations, and improving in robotic positioners and movers used in industrial processing and manufacturing.”

Ristroph's lab frequently addresses these kinds of colorful real-world puzzles. For instance, in 2018, Ristroph and colleagues fine-tuned the recipe for the perfect bubble based on experiments with soapy thin films. In 2021, the Ristroph lab looked into the formation processes underlying so-called "stone forests" common in certain regions of China and Madagascar.

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Inside the hands-on lab of an experimental archaeologist

2 January 2025 at 12:00

Back in 2019, we told you about an intriguing experiment to test a famous anthropological legend about an elderly Inuit man in the 1950s who fashioned a knife out of his own frozen feces. He used it to kill and skin a dog, using its rib cage as a makeshift sled to venture off into the Arctic. Metin Eren, an archaeologist at Kent State University, fashioned rudimentary blades out of his own frozen feces to test whether they could cut through pig hide, muscle, and tendon.

Sadly for the legend, the blades failed every test, but the study was colorful enough to snag Eren an Ig Nobel Prize the following year. And it's just one of the many fascinating projects routinely undertaken in his Experimental Archaeology Laboratory, where he and his team try to reverse-engineer all manner of ancient technologies, whether they involve stone tools, ceramics, metal, butchery, textiles, and so forth.

Eren's lab is quite prolific, publishing 15 to 20 papers a year. “The only thing we’re limited by is time,” he said. Many have colorful or quirky elements and hence tend to garner media attention, but Eren emphasizes that what he does is very much serious science, not entertainment. “I think sometimes people look at experimental archaeology and think it’s no different from LARPing,” Eren told Ars. “I have nothing against LARPers, but it’s very different. It’s not playtime. It’s hardcore science. Me making a stone tool is no different than a chemist pouring chemicals into a beaker. But that act alone is not the experiment. It might be the flashiest bit, but that's not the experimental process.”

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Evolution journal editors resign en masse [UPDATED]

30 December 2024 at 18:45

Over the holiday weekend, all but one member of the editorial board of Elsevier's Journal of Human Evolution (JHE) resigned "with heartfelt sadness and great regret," according to Retraction Watch, which helpfully provided an online PDF of the editors' full statement. It's the 20th mass resignation from a science journal since 2023 over various points of contention, per Retraction Watch, many in response to controversial changes in the business models used by the scientific publishing industry.

"This has been an exceptionally painful decision for each of us," the board members wrote in their statement. "The editors who have stewarded the journal over the past 38 years have invested immense time and energy in making JHE the leading journal in paleoanthropological research and have remained loyal and committed to the journal and our authors long after their terms ended. The [associate editors] have been equally loyal and committed. We all care deeply about the journal, our discipline, and our academic community; however, we find we can no longer work with Elsevier in good conscience."

The editorial board cited several changes made over the last ten years that it believes are counter to the journal's longstanding editorial principles. These included eliminating support for a copy editor and a special issues editor, leaving it to the editorial board to handle those duties. When the board expressed the need for a copy editor, Elsevier's response, they said, was "to maintain that the editors should not be paying attention to language, grammar, readability, consistency, or accuracy of proper nomenclature or formatting."

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Ten cool science stories we almost missed

30 December 2024 at 14:37

There is rarely time to write about every cool science paper that comes our way; many worthy candidates sadly fall through the cracks over the course of the year. But as 2024 comes to a close, we've gathered ten of our favorite such papers at the intersection of science and culture as a special treat, covering a broad range of topics: from reenacting Bronze Age spear combat and applying network theory to the music of Johann Sebastian Bach, to Spider-Man inspired web-slinging tech and a mathematical connection between a turbulent phase transition and your morning cup of coffee. Enjoy!

Reenacting Bronze Age spear combat

Experiment with experienced fighters who spar freely using different styles. An experiment with experienced fighters who spar freely using different styles. Credit: Valerio Gentile/CC BY

The European Bronze Age saw the rise of institutionalized warfare, evidenced by the many spearheads and similar weaponry archaeologists have unearthed. But how might these artifacts be used in actual combat? Dutch researchers decided to find out by constructing replicas of Bronze Age shields and spears and using them in realistic combat scenarios. They described their findings in an October paper published in the Journal of Archaeological Science.

There have been a couple of prior experimental studies on bronze spears, but per Valerio Gentile (now at the University of Gottingen) and coauthors, practical research to date has been quite narrow in scope, focusing on throwing weapons against static shields. Coauthors C.J. van Dijk of the National Military Museum in the Netherlands and independent researcher O. Ter Mors each had more than a decade of experience teaching traditional martial arts, specializing in medieval polearms and one-handed weapons. So they were ideal candidates for testing the replica spears and shields.

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The physics of ugly Christmas sweaters

27 December 2024 at 19:00

'Tis the season for many holiday traditions, including the Ugly Christmas Sweater—you know, those 1950s-style heavy knits featuring some kind of cartoonish seasonal decoration, like snowflakes, Santa Claus, or—in the case of Mark Darcy from Bridget Jones' Diary (2001)—Rudolph the Red-Nosed Reindeer. "It’s obnoxious and tacky, but also fuzzy and kind of wholesome—the fashion equivalent of a Hallmark Christmas movie (with a healthy dose of tongue-in-cheek)," as CNN's Marianna Cerini recently observed.

Fashion (or lack thereof) aside, sweaters and other knitted fabric are also fascinating to physicists and mathematicians. Case in point: a recent paper published in the journal Physical Review Letters examining the complex mechanics behind the many resting shapes a good Jersey knit can form while at rest.

Knitted fabrics are part of a class of intertwined materials—which also includes birds' nests, surgical knots, knotted shoelaces, and even the degradation of paper fibers in ancient manuscripts. Knitted fabrics are technically a type of metamaterial: an engineered material that gets its properties not from the base materials but from their designed structures. The elasticity (aka, stretchiness) of knitted fabrics is an emergent property: the whole is more than the sum of its parts. How those components (strands of yarn) are arranged at an intermediate scale (the structure) determines the macro scale properties of the resulting fabric.

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Could microwaved grapes be used for quantum sensing?

27 December 2024 at 15:46

There are thousands of YouTube videos in which DIY science enthusiasts cut grapes in half—leaving just a thin bit of skin connecting them—and put the grapes in the microwave, just to marvel at the sparks and plume of ionized gas (plasma) that the grapes produce. This quirky property of grapes might help make more efficient quantum sensors, according to a new paper published in the journal Physical Review Applied.

The plasma-inducing grape effect was first observed in 1994, per the authors. As previously reported, the usual explanation for the generation of plasmas is that grapes are so small that the irradiating microwaves become highly concentrated in the grape tissue, ripping some the molecules apart to generate charged ions (adding to the electrolytes already present in the grapes). The electromagnetic field that forms causes ions to flow from one grape half to the other via the connecting skin—at least at first. That's when you get the initial sparks. Eventually, the ions start passing through the surrounding air as well, ionizing it to produce that hot plume of plasma.

But in 2019, Trent University scientists showed that explanation isn't quite right. The skin bridge isn't necessary for the effect to occur. Rather, the plasma is generated by an electromagnetic "hot spot." The grapes have the right refractive index and size to "trap" microwaves, so putting two of them close together leads to the generation of a hot spot between them. The trick also works with gooseberries, large blackberries, and quail eggs, as well as hydrogel beads—plastic beads soaked in water. ("Many microwaves were in fact harmed during the experiments," co-author Hamza Khattak admitted at the time.)

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These squirrels are cold-blooded vole killers

18 December 2024 at 09:00
They seem so sweet and innocent but these squirrels are also opportunistic killers.

We think of squirrels as adorably harmless creatures, admiring their bushy tails and twitchy little noses and the way they cram their cheeks with nuts or seeds to bring back to their nests for later. But the rodents turn out to be a bit more bloodthirsty than we thought. According to a new paper published in the Journal of Ethology, California ground squirrels have been caught in the act—many times over—of chasing, killing, and eating voles.

Co-author Jennifer Smith, a biologist at the University of Wisconsin, Eau Claire, described the behavior as "shocking," given the sheer number of times they watched squirrels do this. “We had never seen this behavior before," she said. "Squirrels are one of the most familiar animals to people. We see them right outside our windows; we interact with them regularly. Yet here’s this never-before-encountered-in-science behavior that sheds light on the fact that there’s so much more to learn about the natural history of the world around us.”

Squirrels mainly consume acorns, seeds, nuts, and fruits, but they have been known to supplement that diet with insects and, occasionally, by stealing eggs or young hatchlings from nests. And back in 1993, biologist J.R Callahan caused a stir by reporting that as many as 30 species of squirrel could be preying on smaller creatures: namely, fish, amphibians, reptiles, birds, and the occasional small mammal.

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AI helps ID paint chemistry of Berlin Wall murals

12 December 2024 at 16:59

The fall of the Berlin Wall in November 1989 was a seminal moment in 20th century history, paving the way for German reunification. Many segments, both large and small, were preserved for posterity—including portions covered in graffiti or murals. A team of Italian scientists used a combination of spectroscopic analysis and machine learning to study paint chips from wall fragments to learn more about the chemistry of the paints and pigments used, according to a new paper published in the Journal of the American Chemical Society.

There has been increased attention in recent years to preserving street art, which is vulnerable both to degradation over time as well as deliberate vandalism. For instance, in 2021, Italian chemists figured out how to use hydrogels to remove added graffiti from vandalized murals in Florence. (Over-painting by vandals is so chemically similar to the original painting underneath that it is difficult to selectively remove just the over-painting without damaging the original.) Unlike most classic masterpieces of the past, created with paints designed to last centuries, street art is more ephemeral in nature, using materials that lack such longevity.

In many cases, like the Berlin Wall, the painters didn't bother to document the specific materials they used, their application techniques, or other useful information that conservators could use to restore or conserve street art. Modern painting materials are also much more complex, and manufacturers typically do not report specific information on the composition of those materials.

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Paleolithic deep-cave compound likely used for rituals

9 December 2024 at 20:00

Archaeologists excavating a paleolithic cave site in Galilee, Israel, have found evidence that a deep-cave compound at the site may have been used for ritualistic gatherings, according to a new paper published in the Proceedings of the National Academy of Sciences (PNAS). That evidence includes the presence of a symbolically carved boulder in a prominent placement, and well as the remains of what may have been torches used to light the interior. And the acoustics would have been conducive to communal gatherings.

Dating back to the Early Upper Paleolithic period, Manot Cave was found accidentally when a bulldozer broke open its roof during construction in 2008. Archaeologists soon swooped in and recovered such artifacts as stone tools, bits of charcoal, remains of various animals, and a nearly complete human skull.

The latter proved to be especially significant, as subsequent analysis showed that the skull (dubbed Manot 1) had both Neanderthal and modern features and was estimated to be about 54,700 years old. That lent support to the hypothesis that modern humans co-existed and possibly interbred with Neanderthals during a crucial transition period in the region, further bolstered by genome sequencing.

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Latest James Webb data hints at new physics in Universe’s expansion

9 December 2024 at 14:00

Physicists have been puzzling over conflicting observational results pertaining to the accelerating expansion rate of our Universe—a major discovery recognized by the 2011 Nobel Prize in Physics. New observational data from the James Webb Space Telescope (JWST) has confirmed that prior measurements of distances between nearby stars and galaxies made by the Hubble Space Telescope are not in error, according to a new paper published in The Astrophysical Journal. That means the discrepancy between observation and our current theoretical model of the Universe is more likely to be due to new physics.

As previously reported, the Hubble Constant is a measure of the Universe's expansion expressed in units of kilometers per second per megaparsec (Mpc). So, each second, every megaparsec of the Universe expands by a certain number of kilometers. Another way to think of this is in terms of a relatively stationary object a megaparsec away: Each second, it gets a number of kilometers more distant.

How many kilometers? That's the problem here. There are basically three methods scientists use to measure the Hubble Constant: looking at nearby objects to see how fast they are moving, gravitational waves produced by colliding black holes or neutron stars, and measuring tiny deviations in the afterglow of the Big Bang known as the Cosmic Microwave Background (CMB). However, the various methods have come up with different values. For instance, tracking distant supernovae produced a value of 73 km/s Mpc, while measurements of the CMB using the Planck satellite produced a value of 67 km/s Mpc.

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E-tattoos could make mobile EEGs a reality

5 December 2024 at 15:31
A 3D-printable EEG electrode e-tattoo. Credit: University of Texas at Austin.

Epidermal electronics attached to the skin via temporary tattoos (e-tattoos) have been around for more than a decade, but they have their limitations, most notably that they don't function well on curved and/or hairy surfaces. Scientists have now developed special conductive inks that can be printed right onto a person's scalp to measure brain waves, even if they have hair. According to a new paper published in the journal Cell Biomaterials, this could one day enable mobile EEG monitoring outside a clinical setting, among other potential applications.

EEGs are a well-established, non-invasive method for recording the electrical activity of the brain, a crucial diagnostic tool for monitoring such conditions as epilepsy, sleep disorders, and brain injuries. It's also an important tool in many aspects of neuroscience research, including the ongoing development of brain-computer interfaces (BCIs). But there are issues. Subjects must wear uncomfortable caps that aren't designed to handle the variation in people's' head shapes, so a clinician must painstakingly map out the electrode positions on a given patient's head—a time-consuming process. And the gel used to apply the electrodes dries out and loses conductivity within a couple of hours, limiting how long one can make recordings.

By contrast, e-tattoos connect to skin without adhesives, are practically unnoticeable, and are typically attached via temporary tattoo, allowing electrical measurements (and other measurements, such as temperature and strain) using ultra-thin polymers with embedded circuit elements. They can measure heartbeats on the chest (ECG), muscle contractions in the leg (EMG), stress levels, and alpha waves through the forehead (EEG), for example.

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These spiders listen for prey before hurling webs like slingshots

4 December 2024 at 23:00
A tethered mosquito approaches the web in the path of release of the cone, and triggers web release response. Credit: S.I. Han and T.A. Blackledge, 2024.

Ray spiders deploy an unusual strategy to capture prey in their webs. They essentially pull it back into a cone shape and release it when prey approaches, trapping said prey in the sticky silken threads. A few years ago, scientists noticed that they could get the spiders to release their webs just by snapping their fingers nearby, suggesting that the spiders relied at least in part on sound vibrations to know when to strike. Evidence for that hypothesis has now been confirmed in a new paper published in the Journal of Experimental Biology.

Most spider orb webs are static: the spiders weave them and fix them in place and then wait for prey to fly into the webs. That causes the silk threads to vibrate, alerting the spider that dinner is served. There are some species that actively actuate their webs, however, per the authors.

For instance, the triangle weaver spring-loads its triangular web once an insect has made contact so that the threads wrap around the prey in fractions of a second. Bolas spiders seem to detect prey in their vicinity through auditory cues, throwing a line of silk with a sticky end at passing moths to catch them. Ogre-faced spiders also seem to be able to hear potential prey, striking backward with a small silk net held in their front legs. It's a more proactive hunting strategy than merely waiting for prey to fly into a web.

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© S.I. Han and T.A. Blackledge, 2024

A peek inside the restoration of the iconic Notre Dame cathedral

3 December 2024 at 17:58

On April 15, 2019, the world watched in transfixed horror as a fire ravaged the famed Cathedral of Notre Dame in Paris, collapsing the spire and melting the lead roof. After years of painstaking restoration costing around $740 million, the cathedral reopens to the public this weekend. The December issue of National Geographic features an exclusive look inside the restored cathedral, accompanied by striking photographs by Paris-based photographer and visual artist Tomas van Houtryve.

For several hours, it seemed as if the flames would utterly destroy the 800-year-old cathedral. But after a long night of work by more than 400 Paris firefighters, the fire finally began to cool and attention began to shift to what could be salvaged and rebuilt. French President Emmanuel Macron vowed to restore Notre Dame to its former glory and set a five-year deadline. The COVID-19 pandemic caused some delays, but France nearly met that deadline regardless.

Those reconstruction efforts were helped by the fact that, a few years before the fire, scientist Andrew Tallon had used laser scanning to create precisely detailed maps of the interior and exterior of the cathedral—an invaluable aid as Paris rebuilds this landmark structure. French acousticians had also made detailed measurements of Notre Dame's "soundscape" that were instrumental in helping architects factor acoustics into their reconstruction plans. The resulting model even enabled Brian FG Katz, research director of the National Center for Scientific Research (CNRS) at Sorbonne University, to create a virtual reality version of Notre Dame with all the acoustical parameters in place.

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Cheerios effect inspires novel robot design

3 December 2024 at 15:39

There's a common popular science demonstration involving "soap boats," in which liquid soap poured onto the surface of water creates a propulsive flow driven by gradients in surface tension. But it doesn't last very long since the soapy surfactants rapidly saturate the water surface, eliminating that surface tension. Using ethanol to create similar "cocktail boats" can significantly extend the effect because the alcohol evaporates rather than saturating the water.

That simple classroom demonstration could also be used to propel tiny robotic devices across liquid surfaces to carry out various environmental or industrial tasks, according to a preprint posted to the physics arXiv. The authors also exploited the so-called "Cheerios effect" as a means of self-assembly to create clusters of tiny ethanol-powered robots.

As previously reported, those who love their Cheerios for breakfast are well acquainted with how those last few tasty little "O"s tend to clump together in the bowl: either drifting to the center or to the outer edges. The "Cheerios effect is found throughout nature, such as in grains of pollen (or, alternatively, mosquito eggs or beetles) floating on top of a pond; small coins floating in a bowl of water; or fire ants clumping together to form life-saving rafts during floods. A 2005 paper in the American Journal of Physics outlined the underlying physics, identifying the culprit as a combination of buoyancy, surface tension, and the so-called "meniscus effect."

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© Jackson K. Wilt et al. 2024

What fossilized dino feces can tell us about their rise to dominance

27 November 2024 at 21:00

Paleontologists have long puzzled over how the dinosaurs—originally relatively small and of minor importance to the broader ecosystem—evolved to become the dominant species some 30 million years later. Fossilized feces and vomit from dinosaurs might hold important clues to how and why this evolutionary milestone came about, according to a new paper published in the journal Nature.

Co-author Martin Qvarnström, an evolutionary biologist with Uppsala University in Sweden, and his collaborators studied trace fossils known as bromalites, a designation that includes coprolites as well as vomit or other fossilized matter from an organism's digestive tract. As previously reported, coprolites aren't quite the same as paleofeces, which retain a lot of organic components that can be reconstituted and analyzed for chemical properties. Coprolites are fossils, so most organic components have been replaced by mineral deposits like silicate and calcium carbonates.

For archaeologists keen on learning more about the health and diet of past populations—as well as how certain parasites evolved in the evolutionary history of the microbiome—coprolites and paleofeces can be a veritable goldmine of information. For instance, in 2021 we reported on an analysis of preserved paleo-poop revealing that ancient Iron Age miners in what is now Austria were fond of beer and blue cheese.

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© Marcin Ambrozik

Licking this “lollipop” will let you taste virtual flavors

26 November 2024 at 19:52
Demonstrating lollipop user interface to simulate taste in virtual and augmented reality environments. Credit: Lu et al, 2024/PNAS

Virtual reality (VR) technology has long sought to incorporate the human senses into virtual and mixed-reality environments. In addition to sight and sound, researchers have been trying to add the sensation of human touch and smell via various user interfaces, as well as taste. But the latter has proved to be quite challenging. A team of Hong Kong scientists has now developed a handheld user interface shaped like a lollipop capable of re-creating several different flavors in a virtual environment, according to a new paper published in the Proceedings of the National Academy of Sciences (PNAS).

It's well established that human taste consists of sweet, salty, sour, bitter, and umami—five basic flavors induced by chemical stimulation of the tongue and, to a lesser extent, in parts of the pharynx, larynx, and epiglottis. Recreating those sensations in VR has resulted in a handful of attempts at a flavor user interface, relying on such mechanisms as chemical, thermal, and electrical stimulation, as well as iontophoresis.

The chemical approach usually involves applying flavoring chemicals directly onto the tongue, but this requires room for bulk storage of said chemicals, and there is a long delay time that is not ideal for VR applications. Thermal variations applied directly to the tongue can stimulate taste sensations but require a complicated system incorporating a cooling subsystem and temperature sensors, among other components.

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