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An arm bone from an ancient human that lived 700,000 years ago on the island of Flores is the smallest ever found from an adult hominin, adding a new piece to the puzzle of Homo floresiensis

The International Space Station will burn up and splash down into the Pacific sometime around 2030. What could possibly go wrong? And will we ever see anything like the ISS again?

To transport our planet across the universe, we would need to bring the whole solar system to sustain life on Earth – on this episode of Dead Planets Society, our hosts contemplate how to shepherd all that baggage on this scenic journey

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An exquisitely camouflaged lizard has a desiccated landscape of sand and stones “painted” on its back. Its skin can be read as a description of an ancient desert, a world in which its ancestors survived. Such descriptions are more than skin deep, however. They penetrate the very warp and woof of the entire animal.

In this groundbreaking exploration of the power of Darwinian evolution and what it can reveal about the past, Richard Dawkins shows how the body, behavior, and genes of every living creature can be read as a book—an archive of the worlds of its ancestors. In the future, a zoologist presented with a hitherto unknown animal will be able to decode its ancestral history, to read its unique “book of the dead.” Such readings are already uncovering the remarkable ways animals overcome obstacles, adapt to their environments, and, again and again, develop remarkably similar ways of solving life’s problems.

From the author of The Selfish Gene comes a revolutionary, richly illustrated book that unlocks the door to a past more vivid, nuanced, and fascinating than anything we have seen.

Richard Dawkins was the inaugural Charles Simonyi Professor for the Public Understanding of Science at Oxford University. His numerous books include the best-selling The Selfish Gene, The God Delusion, and The Blind Watchmaker. He also wrote The Magic of Reality, The Ancestor’s Tale, Unweaving the Rainbow, Climbing Mount Improbable, and The Extended Phenotype. He lives in Oxford, UK. His new book is The Genetic Book of the Dead: A Darwinian Reverie, which is beautifully illustrated on nearly every page by Jana Lenzová. Jana Lenzová is a translator and illustrator and is acclaimed for her work on Dawkins’s book Flights of Fancy, about the evolution of flight. She lives in Oxford, UK.

Shermer and Dawkins discuss:

• History as a science: archaeology, paleontology, evolutionary biology, geology, cosmology, human history, genetic book of the dead
• Genetic Book of the Dead or Phenotypic Book of the Dead?
• Is this a bookend with The Selfish Gene?
• Horned lizard of the Mojave desert
• QR codes, genetic codes, computer codes…information as a proxy for past environments
• Sir D’Arcy Thompson: ‘Everything is the way it is because it got that way.’ Dawkins: “The genome of every individual is a sample of the gene pool of the species. The gene pool got to be the way it is over many generations, partly through random drift, but more pertinently through a process of non-random sculpture. The sculptor is natural selection, carving and whittling the gene pool until it – and the bodies that are its outward and visible manifestation – are the way they are.”
• The species as averaging computer: The genetic book of the dead is a written description of the world of no particular ancestral individual more than another. It is a description of the environments that sculpted the whole gene pool.
• Our human palimpsest has ‘quadruped’ boldly written in a firm hand, then over-written all too superficially with the tracery of a new description – biped.
• Intermediate stages of evolution revealed by palimpsests: “Galápagos marine iguanas are proficient swimmers, but they can manage a surprising turn of speed on land too, when fleeing snakes. All these animals show us what the intermediates might have been like, on the way to becoming dedicated mariners like whales, dugongs, plesiosaurs, and ichthyosaurs.”
• Double doubling back: land and sea tortoises
• Apply this to fossil species of tortoises to determine where they lived, to “read” the ancestral environment
• “Constraints on perfection” older scripts of the palimpsest restrain newer scripts (legacy of history): “buried deep in embryology and deep in history” = “buried deep under layers of younger scripts in the palimpsest”
• Vertebrate retina installed back to front
• Wasteful detour of the laryngeal nerve
• Blind spot in the retina
• Panda’s thumb
• Vertebrate skeleton: spinal column, skull and tail at the two ends, column of serially segmented vertebrae, four limbs consisting of a single long bone (humerus or femur), two parallel bones (radius/ulna), cluster of smaller bones (digits), usually 5
• Pseudogenes/junk genes: the genetic palimpsest (computer disc analogy)
• Reverse engineering
• Adaptationism
• Good enough vs. optimal (satisficing), QWERTY
• Transitional fossils
• Constraints on Perfection
• Common problems, common solutions: evolutionary convergence
• Matt Ridley’s How Innovation Works and implications for how evolution works
• What it’s like to be a bat
• False colors in astronomical photographs and fMRI brain scans
• The Middle World of our evolutionary past and constraints on cognition.

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by Greg Mayer

Once Jerry is well-ensconced in South Africa, I’m sure he’ll have plenty of wildlife photos for us, including some warthogs. In the meantime here’s some wildlife I observed in Toledo, Ohio.

In Late June, I attended the annual meeting of the Society for the Study of Amphibians and Reptiles at the University of Michigan in Ann Arbor, and there was an optional field trip to the Toledo Zoo, which included a visit to a prairie restoration on the banks of the Maumee River near the Zoo grounds.

Matt Cross, Director of Vertebrate Conservation at the Toledo Zoo, directs visiting herpetologists onto the prairie. The “tent” in the background is a device for sampling invertebrates.

Toledo is at the far eastern edge of the “Prairie Peninsula“, where there were only a few scattered stands of prairie at he time of settlement, so this is less a restoration than a creation.The particular patch we went to is on formerly developed land, so many plants were brought in when this patch was established in 2013. This looks like a Black-eyed Susan (Rudbeckia hirta); note the bristly, lanceolate leaves, and 10-13 rays in the flowers pictured.

Rudbeckia hirta, Toledo, Ohio, 27 June 2024.

Although we tend to think of cactus as Southwestern, they occur in Midwestern prairies (and even further east on sandy soils) as well.

Eastern Prickly Pear, Opuntia humifusa, Toledo, Ohio, 27 June 2024.

The Zoo uses cover boards, a commonly used technique, to sample small vertebrates and arthropods.

Cover boards in a small (ca. 2/3 acre) restored prairie in Toledo, Ohio.

And under the cover boards were Northern Brown Snakes (Storeria dekayi).

Storeria dekayi, Toledo, Ohio, 27 June 2024. Storeria dekayi, Toledo, Ohio, 27 June 2024.

Lots of them! I think the one on the left is a gravid female.

Storeria dekayi, Toledo, Ohio, 27 June 2024.

And, they acted appropriately, engaging in volmerolfaction, sampling the air for chemicals with the tongue, to be sensed by the Jacobson’s organ in the roof of the mouth.

Storeria dekayi, Toledo, Ohio, 27 June 2024

A member of the Zoo staff turned a board in front of me, revealing a nice one. I instinctively grabbed it, quickly handing it to her because I wasn’t sure if handling by us visitors was allowed, but we were, in fact allowed to be herpetologists! Northern Browns are common in Illinois prairies I have visited, and persist in urban and suburban habitats in New York, so it’s not surprising to see them here in Toledo.

There were also invertebrates under the boards,

An ant nest; note the winged individuals. Toledo, Ohio, 27 June 2024

and birds above the boards. A Turkey Vulture (Cathartes aura) soars overhead.

Cathartes aura, Toledo, Ohio, 27 June 2024

A young Bald Eagle (Haliaeetus leucocephalus) perches in a tree on the banks of the Maumee.

Haliaeetus leucocephalus, Toledo, Ohio, 27 June 2024

And a Great Blue Heron (Ardea herodias) was striding around Clark Island, an island being terraformed and enlarged in the Maumee.

Ardea herodias, Toledo, Ohio, 27 June 2024

While walking back to the Zoo proper, we also got to see a Five-lined Skink (Eumeces fasciatus) on a boundary fence at the Zoo.

Eumeces fasciatus, Toledo, Ohio, 27 June 2024.

This was an especial treat for me, because, although I am a lizard specialist, I grew up in the Northeast and have lived for many years in the Midwest, and lizards are not especially diverse or abundant in either region, so it was nice seeing a live, wild lizard!

The claim that medical error is the third leading cause of death in the US has never been close to true.

The question of whether or not red dwarf stars can support habitable planets has been subject to debate for decades. With the explosion in exoplanet discoveries in the past two decades, the debate has become all the more significant. For starters, M-type (red dwarf) stars are the most common in the Universe, accounting for 75% of the stars in our galaxy. Additionally, exoplanet surveys indicate that red dwarfs are particularly good at forming Earth-like rocky planets that orbit within their circumsolar habitable zones (CHZs).

Unfortunately, a considerable body of research has shown that planets orbiting red dwarf suns would be subject to lots of flare activity – including some so powerful they’re known as “superflares.” In a recent study led by the University of Hawai’i, a team of astrophysicists revealed that red dwarf stars can produce stellar flares with significantly more far-ultraviolet radiation than previously expected. Their findings could have drastic implications for exoplanet studies and the search for extraterrestrial life on nearby rocky planets.

The study was led by Vera L Berger, a Churchill Scholar and graduate student researcher currently at the University of Cambridge’s Cavendish Laboratory, formerly with the University of Hawai‘i’s Institute for Astronomy (UHIfA). She was joined by colleagues from UHIfA, the Center for Cosmology and Astroparticle Physics (CCAP) at Ohio State University, and the Sydney Institute for Astronomy (SIfA). Their findings appeared in a paper titled “Stellar flares are far-ultraviolet luminous,” which was recently published in the Monthly Notices of the Royal Astronomical Society.

Artist’s impression of Kepler-1649 c orbiting its host star, a red dwarf. Credit: NASA’s Ames Research Center/Daniel Rutter

In recent years, the debate regarding red dwarf habitability has focused on two major areas: tidal locking and flare activity. The former arises from the fact that rocky planets orbiting a red dwarf star’s CMZ are close enough that their rotation is perfectly timed with their orbit, meaning that one side is constantly facing toward the star. This also means that the sun-facing side would be subject to powerful solar flares, which are very with cooler, low-mass M-type stars. In the past, research has shown that a planet subjected to this powerful flare activity would likely be stripped of its atmosphere.

However, other research has indicated that planets with a magnetic field and a sufficiently dense atmosphere could still support life. Moreover, recent research has demonstrated that red dwarfs emit their most powerful flares (aka. “superflares”) from their poles, thus sparing the planets that orbit them. For their study, Berger and her team used archival data from NASA’s Galaxy Evolution Explorer (GALEX) – a UV space telescope decommissioned in 2013. Using new computational techniques, the team searched this data for evidence of flares from 300,000 nearby stars.

Overall, they detected 182 flares from 158 stars within about 326 light-years (100 parsecs) of the Sun in the near-ultraviolet (NUV) and far-ultraviolet (FUV) wavelengths. These results challenge existing models of stellar flares and exoplanet habitability, which predict that flares will produce more NUV than FUV radiation. However, their observations showed that the distribution of FUV radiation was three times more energetic (on average) and up to twelve times what current models predict. As Bergin explained in a recent UH press release:

“Few stars have been thought to generate enough UV radiation through flares to impact planet habitability. Our findings show that many more stars may have this capability… Our work puts a spotlight on the need for further exploration into the effects of stellar flares on exoplanetary environments. Using space telescopes to obtain UV spectra of stars will be crucial for better understanding the origins of this emission.”

Artist’s illustration of Proxima Centauri b. ESO/M. Kornmesser

On Earth, ultraviolet radiation has been vital to the development of life as we know it. Whereas near-UV (UV-A, 400 nm to 300 nm) plays an essential role in the formation of Vitamin D by the skin, prolonged exposure can lead to sunburn, increased risk of melanoma, and cataracts. Middle wavelength UV (UV-B, 300 to 200 nm) can cause damage at the molecular level, affecting deoxyribonucleic acid (DNA), the very building blocks of life. Thanks to Earth’s magnetic field and dense atmosphere, very little UV light below 290 nm reaches the surface.

However, as the team indicates in their study, exposure to Far-UV (200 nm to 10 nm) produced by stellar flares could severely impact planetary habitability, from eroding a planet’s atmosphere to threatening the formation of RNA building blocks. “A change of three is the same as the difference in UV in the summer from Anchorage, Alaska to Honolulu, where unprotected skin can get a sunburn in less than 10 minutes,” said co-author Benjamin J. Shappee from the University of Hawai’i.

While the exact cause of these stronger FUV emissions is unclear, the team believes that flare radiation could be concentrated at specific wavelengths, possibly due to elements like carbon and nitrogen in the star’s composition. They emphasize that more data is needed to determine the source of these emissions and to gain a better understanding of red dwarf UV luminosity. These findings could indicate that most stars in our galaxy cannot support life (as we know it), which could have drastic implications for astrobiology and might even be a possible answer to Fermi’s Paradox!

Further Reading: University of Hawai’i, MNRAS

The post Habitable Planet’s Orbiting Red Dwarf Suns Could at Risk from Far-Ultraviolet Radiation appeared first on Universe Today.

Mention the name Starlink among the astronomy community and you will often be greeted with a shudder. There are now thousands of Starlink satellites orbiting Earth providing internet connectivity to every corner of the Earth. Many believe they are making astronomy difficult but now, SpaceX is launching another service; ‘direct-to-cell’ technology that will allow mobile phones to use satellites to send text messages as early as this year. Voice and data services are likely to follow on quickly next year. With smaller antennae at a lower altitude what is their impact on astronomy?

The SpaceX Starlink satellite project provides high speed broadband to ever corner of the globe (I know globes don’t have corners but it’s a saying that I didn’t write, I’m just using it…. reluctantly.) Thousands of small satellites are now in low Earth orbit to achieve that aim. It’s great news to those that live in remote parts of Earth and it has massive benefits to communications and support applications like disaster relief, medicine and remote learning. To astronomers attempting to study the faintest light from distant objects across the cosmos the satellites are problematic, having a negative impact on many observations. 

This diagram and artist illustration demonstrates how sunlight reflects off a Starlink version 1.5 satellite. (Credit: SpaceX)

SpaceX have gone to great lengths to minimise the impact from their satellites but now they are launching more to service direct messaging from mobile phones, via satellite. With even more satellites in orbit, at a lower orbit too, concerns are mounting of their impact on astronomical observations. The new satellites will have a mean magnitude of 4.62, this is 4.9 times brighter than other Starlink Mini spacecraft! Currently there are only 6 ‘direct-to-cell’ satellites in orbit but the plan is for over 7,000 to join them.

Four researchers; Anthony Mallama, Richard E. Cole, Scott Harrington and J. Respler from the International Astronomical Union have studied the new suite of satellites to see what impact they may have on future observations. In their paper they describe just how they analysed the visibility and how they estimated the brightness of the new mini satellites.

The analysis process began with electronic and visual observations of the 6 test satellites. The electronic observations were taken using the MMT9 (Mini-MegaTORTORA) system at the Special Astrophysical Observatory in Russia. It is made up of 9 x 71mm diameter lenses and 2160 x 2560 CMOS detectors. The brightness observations were recorded along with the satellite distance and phase angle of which both would impact brightness. 

The visual observations techniques is similar to that which is familiar to variable star observers. Brightness estimates are made using nearby reference stars whose brightness is known. They then characterise them before reassessing the impact on the new DTC satellites and the existing internet satellites. 

Despite having arrived at an estimate of brightness 4.9 times brighter than the existing satellites, they are unable to conclude how the different attitudes and operations will impact their brightness. Taking into account their expected operations the brightness is more likely to be just 2.6 times brighter than the existing. They will however, spend far more of their time in Earth’s shadow so will be less visible.  

Source : Brightness Characterization for Starlink Direct-to-Cell Satellites

The post Starlink Direct-to-Cell Satellites are Coming. What Will Be Their Impact on Astronomy? appeared first on Universe Today.

Countries are starting to take steps to cut human sources of methane emissions, but climate change is increasing emissions of the potent greenhouse gas from wetlands

A groundbreaking study has revealed that red dwarf stars can produce stellar flares that carry far-ultraviolet (far-UV) radiation levels much higher than previously believed.

Ancient plants, seeds and insects preserved beneath Greenland’s ice sheet reveal that it once melted completely, raising concerns about sea level rise if it happens again

Modern astronomy would struggle without AI and machine learning (ML), which have become indispensable tools. They alone have the capability to manage and work with the vast amounts of data that modern telescopes generate. ML can sift through large datasets, seeking specified patterns that would take humans far longer to find.

The search for biosignatures on Earth-like exoplanets is a critical part of contemporary astronomy, and ML can play a big role in it.

Since exoplanets are so distant, astronomers pay close attention to the ones that allow transmission spectroscopy. When starlight passes through a planet’s atmosphere, spectroscopy can split the light into different wavelengths. Astronomers then examine the light for the telltale signs of particular molecules. However, chemical biosignatures in exoplanet atmospheres are tricky because natural abiogenic processes can generate some of the same signatures.

This is a model JWST transmission spectrum for an Earth-like planet. It shows the wavelengths of sunlight that molecules like ozone (O3), water (H2O), carbon dioxide (CO2), and methane (CH4) absorb. The y-axis shows the amount of light blocked by Earth’s atmosphere rather than the brightness of sunlight that travels through the atmosphere. The brightness decreases from bottom to top. An understanding of Earth’s spectrum helps scientists interpret spectra from exoplanets. Image Credit: NASA, ESA, Leah Hustak (STScI)

Though the method is powerful, it faces some challenges. Stellar activity like starspots and flares can pollute the signal, and the light from the atmosphere can be very weak compared to the star’s light. If there are clouds or haze in the exoplanet’s atmosphere, that can make it difficult to detect molecular absorption lines in the spectroscopic data. Rayleigh scattering adds to the challenge, and there can also be multiple different interpretations of the same spectroscopic signal. The more of these types of ‘noise’ there is in the signal, the worse the signal-to-noise ratio (SNR) is. Noisy data—data with a low SNR—is a pronounced problem.

We’re still discovering different types of exoplanets and planetary atmospheres, and our models and analysis techniques aren’t complete. When combined with the low SNR problem, the pair comprise a major hurdle.

But machine learning can help, according to new research. “Machine-assisted classification of potential biosignatures in earth-like exoplanets using low signal-to-noise ratio transmission spectra” is a paper under review by the Monthly Notices of the Royal Astronomical Society. The lead author is David S. Duque-Castaño from the Computational Physics and Astrophysics Group at the Universidad de Antioquia in Medellin, Colombia.

The JWST is our most powerful transmission spectroscopy tool, and it’s delivered impressive results. But there’s a problem: observing time. Some observing efforts take an enormous amount of time. It can take a prohibitively high number of transits to detect things like ozone. If we had unlimited amounts of observing time, it wouldn’t matter so much.

One study showed that in the case of TRAPPIST-1e, it can take up to 200 transits to obtain statistically significant detections. The transit number becomes more reasonable if the search is restricted to methane and water vapour. “Studies have demonstrated that using a reasonable number of transits, the presence of these atmospheric species, which are typically associated with a global biosphere, can be retrieved,” the authors write. Unfortunately, methane isn’t as robust a biosignature as ozone.

Given the time required to detect some of these potential biomarkers, the researchers say that it might be better to use the JWST to conduct signal-to-noise ratio (SNR) surveys. “Although this may not allow for statistically significant retrievals, it would at least enable planning for future follow-up observations of interesting targets with current and future more powerful telescopes (e.g., ELT, LUVOIR, HabEx, Roman, ARIEL),” the authors write, invoking the names of telescopes that are in the building or planning stages.

The researchers have developed a machine-learning tool to help with this problem. They say it can fast-track the search for habitable worlds by leveraging the power of AI. “In this work, we developed and tested a machine-learning general methodology intended to classify transmission spectra with low Signal-to-Noise Ratio according to their potential to contain biosignatures,” they write.

Since much of our exoplanet atmosphere spectroscopy data is noise, the ML tool is designed to process it, figure out how noisy it is, and classify atmospheres that may contain methane, ozone, and/or water or as interesting enough for follow-up observations.

The team generated one million synthetic atmospheric spectra based on the well-known TRAPPIST-1 e planet and then trained their ML models on them. TRAPPIST-1e is similar in size to Earth and is a rocky planet in the habitable zone of its star. “The TRAPPIST-1 system has gained significant scientific attention
in recent years, especially in planetary sciences and astrobiology, owing to its exceptional features,” the paper states.

Artist’s impression of TRAPPIST-1e, a rocky exoplanet similar in size to Earth. Credit: NASA/JPL-Caltech

The TRAPPIST-1 star is known for hosting the highest number of rocky planets of any system we’ve discovered. For the researchers, it’s an ideal candidate for training and testing their ML models because astronomers can get favourable SNR readings in reasonable amounts of time. The TRAPPIST-1e planet is likely to have a compact atmosphere like Earth’s. The resulting models were successful and correctly identified transmission spectra with suitable SNR levels.

The researchers also tested their models on realistic synthetic atmospheric spectra of modern Earth. Their system successfully identified synthetic atmospheres that contained methane and/or ozone in ratios similar to those of the Proterozoic Earth. During the Proterozoic, the atmosphere underwent fundamental changes because of the Great Oxygenation Event (GOE).

The GOE changed everything. It allowed the ozone layer to form, created conditions for complex life to flourish and even led to the creation of vast iron ore deposits that we mine today. If other exoplanets developed photosynthetic life, their atmospheres should be similar to the Proterozoic Earth’s, so it’s a relevant marker for biological life. (The recent discovery of dark oxygen has serious implications for our understanding of oxygen as a biomarker in exoplanet atmospheres.)

In their paper, the authors describe the detection of oxygen or ozone as the ‘Crown Jewel’ of exoplanet spectroscopy signatures. But there are abiotic sources as well, and whether or not oxygen or ozone are biotic can depend on what else is in the signature. “To distinguish between biotic and abiotic O2, one can look for specific spectral fingerprints,” they write.

To evaluate the performance of their model, they need to know more than which exoplanet atmospheres are correctly identified (True) and which exoplanet atmospheres are falsely identified (False.)

The results also need to be categorized as either True Positives (TP) or True Negatives (TN), which are related to accuracy, or False Positives (FP) or False Negatives (FN), which are errors. To organize their data they created a classification system they call a Confusion Matrix.

“In the diagram, we introduce the category interesting to distinguish planets that deserve follow-up observations or in-depth analysis,” the authors explain. “We should recall again that is the focus of this work: we do not aim at detecting biosignatures using ML but at labelling planets that are interesting or not.”

The Confusion Matrix has four classifications.

One of the models was successful in identifying likely biosignatures in Proterozoic Earth spectra after only a single transit. Based on their testing, they explain that the JWST would successfully detect most “inhabited terrestrial planets observed with the JWST/NIRSpec PRISM around M-dwarfs located at distances similar or smaller than that of TRAPPIST-1 e.” If they exist, that is.

These results can refine the JWST’s future efforts. The researchers write that “machine-assisted strategies similar to those presented here could significantly optimize the usage of JWST resources for biosignature searching.” They can streamline the process and maximize the chances that follow-up observations can discover promising candidates. The telescope is already two years and seven months into its planned five-and-a-half-year primary mission. (Though the telescope could last for up to 20 years overall.) Anything that can optimize the space telescope’s precious observing time is a win.

All in all, the study presents a machine-learning model that can save time and resources. It quickly sifts through the atmospheric spectra of potentially habitable exoplanets. While it doesn’t identify which ones contain biomarkers, it can identify the best candidates for follow-up after only 1 to 5 transits, depending on the type of atmosphere. Some types would require more transits, but the model still saves time.

“Identifying a planet as interesting will only make the allocation of observing time of valuable resources such as JWST more efficient, which is an important goal in modern astronomy,” they write.

The post Fast-Tracking the Search for Habitable Worlds appeared first on Universe Today.

A research team developed artificial intelligence technology that could find ways to improve researchers' understanding of the chemical reactions involved in ammonia production and other complex chemical reactions.

A research team developed artificial intelligence technology that could find ways to improve researchers' understanding of the chemical reactions involved in ammonia production and other complex chemical reactions.

Using state of the art techniques, researchers use vibrations from traffic to measure underground soil moisture.

Understanding neutrino interactions is crucial for obtaining a complete picture of particle physics and the universe. To date, neutrino interaction cross sections have not been measured at high energy above some hundred gigaelectronvolts at particle colliders. Now, researchers have obtained the first direct observation of electron and muon neutrino interactions in the Teraelectronvolt range at CERN's Large Hadron Collider, using the FASER detector. This study marks a significant step for particle physics research.

With GROVER, a new large language model trained on human DNA, researchers could now attempt to decode the complex information hidden in our genome. GROVER treats human DNA as a text, learning its rules and context to draw functional information about the DNA sequences.

A growing body of AI tools screen how people talk, searching for subtle changes that could indicate mental health concerns like depression or anxiety. A study finds that these tools don't perform consistently across people from different genders and races.

New findings on how sharks achieve drag reduction could inspire the design of riblets for more efficient aircraft and boats. In their investigation of great white shark denticles, researchers found that ridge height and spacing play crucial roles in drag reduction at different swimming speeds. Higher middle ridges aid sharks in efficient cruising at slower speeds, while the lower side ridges become more critical for drag reduction during high-speed hunting bursts. The analysis also suggests that the speeds of an extinct giant shark, megalodon, may not much differ from those of the white shark.

Researchers send entangled photons and laser pulses of the same color over a single optical fiber for the first time.