We all want to 'age successfully' with as few health issues as possible. A new study suggests getting more than seven hours of sleep a night could go a long way to achieving that goal.

The study involved 3,306 participants aged 45 and over, whose sleep habits were recorded in 2011, 2013, and 2015, followed by a health check five years later. The data, analyzed by a team from Wenzhou Medical University in China, showed that those who bank at least seven hours of sleep a night tend to have significantly better health later in life.

"Successful aging was evaluated in 2020 and was defined as being free of major chronic diseases, no physical impairment, high cognitive function, good mental health, and active engagement with life," write the researchers in their published paper.

By the end of the study period, only 455 individuals (13.8 percent) checked all of the successful aging criteria boxes. Of those, 307 (around two thirds) were consistently getting more than seven hours of sleep a night.

The participants were split into five groups based on their sleeping habits across the four years: long stable (8-9 hours of sleep regularly), normal stable (7-8 hours regularly), decreasing (from an average of over 8 to fewer than 6), increasing (from an average of fewer than 6 to over 8), and short stable (5-6 hours regularly).

Chances of successful aging was significantly greater among the long stable and normal stable groups (17.1 percent and 18.1 percent respectively) compared to those in the decreasing (9.9 percent), increasing (10.6 percent), and short stable (8.8 percent) groups.

"Relative to participants with the normal stable sleep duration trajectory, those with the low stable and increasing trajectory had 36 percent and 52 percent lower odds of successful aging, respectively," write the researchers.

"Participants with decreasing trajectories also exhibited lower odds, though this was not statistically significant, likely due to sample size limitations."

The team accounted for factors including weight, alcohol consumption, and sex in their analysis, though the nature of the study can't confirm a direct cause-and-effect link.

What it does offer is more evidence of the importance of consistent, extended sleep.

Previous research has also highlighted seven hours a night as a potential sweet spot for sleep and aging well. We also know there are links between sleep and protection against a wide range of physical and mental health issues.

China, where the research was carried out, has one of the fastest aging populations on the planet – but it's very much a global issue. As the world gets older, we need to ensure it stays healthy as well.

"These findings underscore that chronic sleep deprivation, as well as the patterns of increasing and decreasing sleep duration, are not mere age-related changes," write the researchers.

"Rather, they emerge as pivotal indicators of obstacles in the pursuit of successful aging."

The research has been published in BMC Public Health.

Just five minutes of exercise a day could be enough to noticeably shift blood pressure in a downward direction, new research has found.

High blood pressure is classified as having a reading of 140 millimeters of mercury (mmHg) or higher when blood is being pumped through the arteries – known as systolic pressure – and 90 mmHg or greater when the heart is diastolic, or at rest.

Just a few minutes of activity that gets your heart rate up, such as cycling or climbing stairs, was estimated to lower systolic blood pressure by 0.68 mmHg and diastolic blood pressure by 0.54 mmHg, the data showed.

Also known as hypertension, the condition carries an increased risk of serious health problems, including heart attacks and kidney damage.

"The good news is that whatever your physical ability, it doesn't take long to have a positive effect on blood pressure," says first author and epidemiologist Jo Blodgett from University College London.

"What's unique about our exercise variable is that it includes all exercise-like activities, from climbing the stairs to a short cycling errand, many of which can be integrated into daily routines."

The study was based on a week of activity data and blood pressure readings collected using wearable devices on 14,761 participants.

Daily activity was split into six types: sleep, sedentary behavior, slow walking, fast walking, standing, and vigorous exercise. These daily patterns were then referenced against blood pressure, with several other potential influences (including age and sex) factored in.

The researchers then calculated some 'what if' scenarios – how changing those habits could change blood pressure. For example, a 2 mmHg improvement in SBP was estimated if exercise replaced 21 minutes of sedentary time or 21 minutes of fast walking a day.

"For those who don't do a lot of exercise, walking did still have some positive benefits for blood pressure," says Blodgett. "But if you want to change your blood pressure, putting more demand on the cardiovascular system through exercise will have the greatest effect."

As an observational study involving multiple variables, no direct causal link can be drawn. Nevertheless, as the team analyzed data from a large group of people, there's a strong indication that just a small amount of exercise could affect blood pressure (which other studies have suggested too).

Given the relatively small amount of time needed, and the variety of straightforward exercises that make a difference, the international team behind the research hopes these findings can help the 1.28 billion adults worldwide with hypertension.

"The finding that doing as little as five extra minutes of exercise per day could be associated with measurably lower blood pressure readings emphasizes how powerful short bouts of higher intensity movement could be for blood pressure management," says joint senior author Emmanuel Stamatakis, a professor of physical activity and population health at the University of Sydney.

The research has been published in Circulation.

But as a new study by researchers from the Chinese Academy of Sciences and Reichman University in Israel warns, artificial intelligence may also be inadvertently imitating another, less noble hallmark of modern humanity: trashing the environment.

Fueled by the surging popularity of generative AI systems that include chatbots like ChatGPT and other content-creation systems, we could end up with between 1.2 million and 5 million metric tons of additional electronic waste by the end of this decade.

The new study focuses particularly on large language models (LLMs), a type of AI program that can interpret and produce human language, along with performing related tasks.

Trained on vast datasets of text, LLMs identify statistical relationships underlying the rules and patterns of language and apply them to generate similar content, enabling uncanny capabilities like answering questions, producing images, or writing text.

In addition to its many benefits, however, generative AI has raised a host of philosophical and practical questions for society – from concerns about AI taking our jobs to fears of it being misused by humans, deceiving us, or even becoming self-aware and rebellious.

And as the new study highlights, generative AI is also beginning to raise alarms about the daunting amount of extra e-waste the technology is expected to indirectly generate.

Generative AI is reliant on prompt technological improvements, including to hardware infrastructure as well as to chips. The upgrades needed to keep pace with the technology's growth could compound existing e-waste issues, they note, depending on the implementation of waste-reduction measures.

"LLMs demand considerable computational resources for training and inference, which require extensive computing hardware and infrastructure," the study's authors write. "This necessity raises critical sustainability issues, including the energy consumption and carbon footprint associated with these operations."

Previous research has largely focused on the energy use and associated carbon emissions from AI models, the researchers note, paying relatively little attention to the physical materials involved in the models' life cycle, or the waste stream of electronic equipment left in their wake.

Led by Peng Wang, an expert in resource management with the Chinese Academy of Sciences' Key Lab of Urban Environment and Health, the study's authors calculated a forecast of possible e-waste quantities created by generative AI between 2020 and 2030.

The researchers envisioned four scenarios, each with a different degree of production and use of generative AI systems, from an aggressive, widespread-use scenario to a conservative, more constrained scenario.

Under the more aggressive scenario, total e-waste creation due to generative AI could grow as high as 5 million metric tons between 2023 and 2030, with annual e-waste potentially reaching 2.5 million metric tons by decade's end. That's more or less the equivalent of every person on the planet discarding a smart phone.

The high-usage scenario also forecast that AI's extra e-waste would include 1.5 million metric tons of printed circuit boards and 500,000 metric tons of batteries, which can contain hazardous materials like lead, mercury, and chromium.

Just last year, a mere 2.6 thousand tons of electronics was discarded from AI-devoted technology. Considering the total amount of e-waste from technology in general is expected to rise by around a third to a whopping 82 million tonnes by 2030, it's clear AI is compounding an already serious problem.

By examining these different scenarios, Peng and his colleagues draw attention to an important point: Generative AI doesn't necessarily have to impose such an excessive e-waste burden.

The researchers note the International Energy Agency and many tech companies advocate for circular economy strategies to address e-waste.

According to the new study, the most effective strategies are lifespan extension and model reuse, which entail extending the longevity of existing infrastructure and reusing key materials and modules in the remanufacturing process.

Implementing circular economy strategies like these could reduce the e-waste burden from generative AI by up to 86 percent, the researchers report.

The study was published in Nature Computational Science.

We finally know what brought light to the dark and formless void of the early Universe.

According to data from the Hubble and James Webb Space Telescopes, the origins of the free-flying photons in the early cosmic dawn were small dwarf galaxies that flared to life, clearing the fog of murky hydrogen that filled intergalactic space. A new paper about the research was published in February.

"This discovery unveils the crucial role played by ultra-faint galaxies in the early Universe's evolution," said astrophysicist Iryna Chemerynska of the Institut d'Astrophysique de Paris.

"They produce ionizing photons that transform neutral hydrogen into ionized plasma during cosmic reionization. It highlights the importance of understanding low-mass galaxies in shaping the Universe's history."

At the beginning of the Universe, within minutes of the Big Bang, space was filled with a hot, dense fog of ionized plasma. What little light there was wouldn't have penetrated this fog; photons would simply have scattered off the free electrons floating around, effectively making the Universe dark.

As the Universe cooled, after about 300,000 years, protons and electrons began to come together to form neutral hydrogen (and a little bit of helium) gas.

Most wavelengths of light could penetrate this neutral medium, but there was very little in the way of light sources to produce it. But from this hydrogen and helium, the first stars were born.

Those first stars delivered radiation that was strong enough to peel electrons away from their nuclei and reionize the gas. By this point, however, the Universe had expanded so much that the gas was diffuse, and could not prevent light from shining out.

By about 1 billion years after the Big Bang, the end of the period known as the cosmic dawn, the Universe was entirely reionized. Ta-da! The lights were on.

But because there's so much murk in the cosmic dawn, and because it's so dim and far away across time and space, we've had trouble seeing what's there.

Scientists thought that the sources responsible for most of the clearing must have been powerful – huge black holes whose accretion produces blazing light, for example, and large galaxies in the throes of star formation (baby stars produce a lot of UV light).

JWST was designed, in part, to peer into the cosmic dawn and try to see what lurks therein. It's been very successful, revealing all sorts of surprises about this crucial time in the formation of our Universe. Surprisingly, the telescope's observations now suggest that dwarf galaxies are the key player in reionization.

An international team led by astrophysicist Hakim Atek of the Institut d'Astrophysique de Paris turned to JWST data on a galaxy cluster called Abell 2744, backed up by data from Hubble.

Abell 2744 is so dense that space-time warps around it, forming a cosmic lens; any distant light traveling to us through that space-time becomes magnified. This allowed the researchers to see tiny dwarf galaxies close to the cosmic dawn.

Then, they used JWST to obtain detailed spectra of these tiny galaxies. Their analysis revealed that, not only are these dwarf galaxies the most abundant galaxy type in the early Universe, they are far brighter than expected.

In fact, the team's research shows that dwarf galaxies outnumber large galaxies by 100 to 1, and their collective output is four times the ionizing radiation usually assumed for larger galaxies.

"These cosmic powerhouses collectively emit more than enough energy to get the job done," Atek said.

"Despite their tiny size, these low-mass galaxies are prolific producers of energetic radiation, and their abundance during this period is so substantial that their collective influence can transform the entire state of the Universe."

It's the best evidence yet for the force behind reionization, but there's more work to be done. The researchers looked at one small patch of the sky; they need to make sure that their sample isn't just an anomalous cluster of dwarf galaxies, but is a representative sample of the entire population in the cosmic dawn.

They intend to study more cosmic lens regions of the sky to obtain a wider sample of early galactic populations. But just on this one sample, the results are incredibly exciting. Scientists have been chasing answers on reionization for as long we've known about it. We're on the brink of finally blowing away the fog.

"We have now entered uncharted territory with the JWST," said astrophysicist Themiya Nanayakkara of Swinburne University of Technology in Australia.

"This work opens up more exciting questions that we need to answer in our efforts to chart the evolutionary history of our beginnings."

The research has been published in Nature.

A version of this article was originally published in March 2024.

The devastation of Pompeii by the eruption of Vesuvius in 79 CE is one of the best-recorded disasters in human history. The ash and pumice that rained down preserved traces of the dying where they fell, leaving us to guess the identities and relationships of the people left frozen in time.

But we humans are imperfect. We navigate the world with perceptions and biases that cloud our observations, no matter how we try to remain objective. A new analysis of DNA retrieved from the victims of Pompeii reveals our assumptions about them were wrong – a discovery that is giving us insight into the bustling life of Pompeii, before a volcano snuffed it out.

"The scientific data we provide do not always align with common assumptions," says geneticist David Reich of Harvard University.

"For instance, one notable example is the discovery that an adult wearing a golden bracelet and holding a child, traditionally interpreted as a mother and child, were an unrelated adult male and child. Similarly, a pair of individuals thought to be sisters, or mother and daughter, were found to include at least one genetic male. These findings challenge traditional gender and familial assumptions."

The volcanic material dumped on Pompeii when Vesuvius exploded acted as a sort of flash fossilization process. It fell on and around the dead and dying, then set in place. When the bodies succumbed to time and decay, they left hollow impressions behind ash.

The ruins were rediscovered in the 19th century; in the 1870s, plaster was poured into the hollows to create casts of the bodies that had created them. But the shapes of the bodies weren't the only thing preserved. The bones left behind were also sealed into the plaster.

The archaeologists who made the casts in the 19th century couldn't have foreseen the emergence of future technology; nevertheless, their work would prove invaluable more than 150 years later. That's because the casts give us context for details preserved in the genetic makeup of the victims, which in turn helps us understand life in Pompeii and Roman-era Italy.

The analysis, led by forensic archaeologist Elena Pilli of the University of Florence in Italy, was conducted on fragmentary skeletal remains from 14 plaster casts, selected from 86 casts that are currently undergoing restoration. This is no easy task, anthropologist Alissa Mittnik of Harvard University and the Max Planck Institute for Evolutionary Anthropology in Germany told ScienceAlert.

"Both the extreme heat during the volcanic eruption and the plaster casting process could be detrimental for long-term DNA preservation. In genetic analyses, we usually try to target skeletal elements that are known to preserve DNA exceptionally well, such as the inner ear portion of the skull or teeth," she explained.

"In this study, we had to be less selective, as we were only able to take samples from the parts of the skeletons that were exposed in damaged casts that were undergoing restoration. The difficulty of obtaining ancient DNA under these circumstances is evident in the fact that only six of 14 sampled individuals provided us with genetic data."

But those six individuals were sufficient to provide a significant challenge to what we thought we knew about the victims of Pompeii.

The casts are excellent, but not perfect, and details can be a little hard to gauge, just by eye, so archaeologists relied on other clues. The ostentatious golden bracelet worn by the person embracing a child was thought to be women's jewelry. The tender affection with which each pair embraced was interpreted as feminine. Both of these assumptions, it turns out, were incorrect.

At the House of the Golden Bracelet, four individuals interpreted as parents and their two children were not genetically related to each other. At least one individual in the embracing pair was a man – and likely the other was, too.

The findings hint at a much deeper, more complex society than we had imagined for Pompeii.

"I had encountered the conventional narratives surrounding some of these groups of victims before studying them scientifically and they seemed plausible to me, therefore I was quite surprised to see that the genetic results uncovered that there is more to these people's stories than 'what meets the eye'," Mittnik told ScienceAlert.

"The findings make us reconsider simplistic interpretations of gender and family dynamics in Roman society that might not reflect modern western intuitions."

The analyses also revealed a greater genetic diversity in Pompeii than was suspected. The individuals studied were mainly descended from relatively recent immigrants from the eastern Mediterranean and Near East, rather than the people who had lived in the local region for centuries.

This is similar to diversity seen more broadly across the Roman region of western Italy, reflecting early forays into globalization, facilitated by strengthening trade across the Roman Empire.

And this is just six individuals in a city of thousands. It's a staggering result. Not only does it give us a new glimpse into the lives of people who lived thousands of years ago, it's a sobering reminder to try and check our biases at the door if we want to conduct an accurate study of human history.

"While our findings allow us to challenge some of the traditional narratives, we must be careful not to repeat the same mistake," Mittnik told ScienceAlert. "Instead, our results emphasize the importance of integrating various lines of evidence and of not superimposing modern assumptions onto ancient contexts."

The research has been published in Current Biology.

It seems like Roald Dahl may have been onto something after all: if you hurt a plant, it screams.

Well, sort of. Not in the same way you or I might scream. Rather, they emit popping or clicking noises in ultrasonic frequencies outside the range of human hearing that increase when the plant becomes stressed.

This, according to a study published in 2023, could be one of the ways in which plants communicate their distress to the world around them.

"Even in a quiet field, there are actually sounds that we don't hear, and those sounds carry information. There are animals that can hear these sounds, so there is the possibility that a lot of acoustic interaction is occurring," said evolutionary biologist Lilach Hadany of Tel Aviv University in Israel.

"Plants interact with insects and other animals all the time, and many of these organisms use sound for communication, so it would be very suboptimal for plants to not use sound at all."

Plants under stress aren't as passive as you might think. They undergo some pretty dramatic changes, one of the most detectable of which (to us humans, at least) is the release of some pretty powerful aromas. They can also alter their color and shape.

These changes can signal danger to other plants nearby, which in response boost their own defenses; or attract animals to deal with the pests that may be harming the plant.

However, whether plants emit other kinds of signals – such as sounds – has not been fully explored. A few years ago, Hadany and her colleagues found that plants can detect sound. The logical next question to ask was whether they can produce it, too.

To find out, they recorded tomato and tobacco plants in a number of conditions. First, they recorded unstressed plants, to get a baseline. Then they recorded plants that were dehydrated, and plants that had had their stems cut. These recordings took place first in a soundproofed acoustic chamber, then in a normal greenhouse environment.

Then, they trained a machine learning algorithm to differentiate between the sound produced by unstressed plants, cut plants, and dehydrated plants.

The sounds plants emit are like popping or clicking noises in a frequency far too high-pitched for humans to make out, detectable within a radius of over a meter (3.3 feet). Unstressed plants don't make much noise at all; they just hang out, quietly doing their plant thing.

By contrast, stressed plants are much noisier, emitting an average up to around 40 clicks per hour depending on the species. And plants deprived of water have a noticeable sound profile. They start clicking more before they show visible signs of dehydrating, escalating as the plant grows more parched, before subsiding as the plant withers away.

The algorithm was able to distinguish between these sounds, as well as the species of plant that emitted them. And it's not just tomato and tobacco plants. The team tested a variety of plants, and found that sound production appears to be a pretty common plant activity. Wheat, corn, grape, cactus, and henbit were all recorded making noise.

But there are still a few unknowns. For example, it's not clear how the sounds are being produced. In previous research, dehydrated plants have been found to experience cavitation, a process whereby air bubbles in the stem form, expand and collapse. This, in human knuckle-cracking, produces an audible pop; something similar could be going on with plants.

We don't know yet if other distress conditions can induce sound, either. Pathogens, attack, UV exposure, temperature extremes, and other adverse conditions could also induce the plants to start popping away like bubble wrap.

It's also not clear whether sound production is an adaptive development in plants, or if it is just something that happens. The team showed, however, that an algorithm can learn to identify and distinguish between plant sounds. It's certainly possible that other organisms could have done the same.

In addition, these organisms could have learned to respond to the noise of distressed plants in various ways.

"For example, a moth that intends to lay eggs on a plant or an animal that intends to eat a plant could use the sounds to help guide their decision," Hadany said.

For us humans, the implications are pretty clear; we could tune into the distress calls of thirsty plants and water them before it becomes an issue.

But whether or not other plants are sensing and responding is unknown. Previous research works have shown that plants can increase their drought tolerance in response to sound, so it's certainly plausible. And this is where the team is pointing the next stage of their research.

"Now that we know that plants do emit sounds, the next question is – 'who might be listening?'" Hadany said.

"We are currently investigating the responses of other organisms, both animals and plants, to these sounds, and we're also exploring our ability to identify and interpret the sounds in completely natural environments."

The research was published in Cell.

An earlier version of this article was published in March 2023.

The amount of sugar in the diets of babies and toddlers could predict their chances of developing type 2 diabetes and high blood pressure later in life.

Researchers from the University of Southern California, the University of California, Berkeley, and McGill University in Canada used a UK research database to investigate the long-term effects of sugar intake in our earliest years.

Collating data on 60,183 people born between 1951 and 1956, the team assessed the relationship between health and wartime sugar rationing; a restriction that ended in the UK in 1953, giving the team a very useful before-and-after boundary for comparison.

From January 1940 to 1953, the average British adult was limited to 41 grams of sugar a day, with no sugar allowed for children under the age of two. Once the restrictions were eased, sugar consumption rose sharply again.

"Studying the long-term effects of added sugar on health is challenging because it is hard to find situations where people are as-if randomly exposed to different nutritional environments early in life and follow them for 50 to 60 years," says University of Southern California economist Tadeja Gracner.

"The end of rationing provided us with a novel natural experiment to overcome these problems."

According to the data, children subjected to sugar rationing during the first 1,000 days of their lives – starting before they're born – had on average a 35 percent lower risk of developing type 2 diabetes as adults, and a 20 percent lower risk of developing hypertension.

Even in cases where rationing lifted while babies were still in the womb, there was a noticeably lower risk, accounting for up to a third of the risk reduction overall. What's more, when health conditions did appear, their onset was more likely to be delayed among those whose sugar intake had been restricted early in life.

"What's fascinating is that sugar levels allowed during rationing mirror today's guidelines," says economist Claire Boone, from McGill University.

"Our study suggests that if parents followed these recommendations, it could lead to significant health benefits for their children."

As striking as the results are, they're not enough to prove direct cause and effect. Though the researchers accounted for a number of potentially influential factors, Brits experienced a variety of cultural changes from the 1950s, not just their sugar intake.

Nevertheless, this is strong evidence that sugar early in life – and even before birth – is hugely influential. Next, the researchers want to study any possible links between sugar and other diseases, such as cancer.

"Sugar early in life is the new tobacco, and we should treat it as such by holding food companies accountable to reformulate baby foods with healthier options," says Paul Gertler, an economist from the University of California, Berkeley.

"We should also tax and regulate the marketing of sugary foods targeted at kids."

The research has been published in Science.

If you've ever thought to yourself, "Gee I sure would like to see some vampire bats on treadmills," then do we have the science for you. That's exactly what a team of scientists has done, and it's not because little Vladi needed to get his chiropteran steps in.

Rather, the new research reveals how vampire bats (Desmodus rotundus) make the most out of their primary food source – the blood they slurp from the mammals on which they feed.

Fascinatingly, the results show an aptitude for the metabolism of the amino acids in the blood they eat. And, moreover, it doesn't take them long to do so. A vampire bat can gallop merrily along, fuelled by a meal of blood consumed only minutes before.

This makes the vampire bat a very unusual animal indeed, since most vertebrates rely primarily on the metabolism of carbohydrates and lipids for energy. But the ability does appear elsewhere in the animal kingdom – in invertebrate animals, such as blood-feeding Tsetse flies.

It's well established that, among mammals, low-intensity aerobic exercise is predominantly fueled by lipids. As the exercise intensity increases, so too does the reliance on carbohydrates as fuel. These fuel sources are oxidized to generate adenosine triphosphate (ATP), the molecule that provides energy to living cells.

How exactly a vampire bat generates ATP from their extremely protein-rich diet was unclear. But physiologists Giulia Rossi of the University of Toronto and Kenneth Welch of McMaster University in Canada realized they could make use of a trait of vampire bats to find out.

Unlike other bat species, vampire bats are very good at running along the ground. So, they figured they could put bats in treadmills that measure their oxygen intake and carbon dioxide output to measure their metabolism as they exercise at different intensities. And, with the bats living temporarily in the lab, the researchers could control their food intake to determine how that metabolism was working.

They caught 24 wild adult vampire bats in Belize, and divided them into groups. One group of nine bats was fed cow's blood enriched with leucine, an essential amino acid (one that mammals can't synthesize) that helps build and repair muscles in humans. A second group of 12 bats was fed cow's blood enriched with glycine, a non-essential amino acid that helps build collagen and acts as a neurotransmitter.

By swapping the ordinary carbons in the amino acids for a relatively unique isotope, they could track what happened to the element as the compounds broke down in the bats' bodies.

The remaining group was fed cow's blood that was not enhanced with amino acids, to provide a baseline for the CO₂ production of an exercising bat.

After feeding, each bat was popped on the treadmill, custom-built for this research. There were three exercise intensities; 10 meters (33 feet) per minute, 20 meters per minute, and 30 meters per minute. The treadmill gradually increased to each target speed, and the bat's breath recorded as it scampered along the conveyor belt. At top speed, there were even little airborne hops.

Once the bats had been put through their paces, the researchers analyzed the rate at which oxygen was consumed, and carbon dioxide produced, the ratio of which is routinely used as an indicator of metabolic fuel use.

The isotopes revealed the production of CO₂ from the metabolization of amino acids was almost immediately present in the breath of bats on the treadmill. This suggests that the animals were rapidly and efficiently making use of their recent protein meals, unlike insects such as mosquitoes which take longer to metabolize the amino acids in the blood on which they feed.

Interestingly, the bats fed the enriched blood showed no discrimination between essential and non-essential amino acids. Their little bodies made the most of the resources provided, whatever those resources were.

"Our findings suggest that major enhancement of flux through these and related metabolic pathways have evolved in vampire bats as an adaptation to make efficient use of those fuels ingested in abundance (i.e. blood proteins and amino acids)," the researchers write, "marking a striking example of convergent evolution among both vertebrate and invertebrate obligate blood-feeding animals."

No bats were harmed in the making of this research. They may, however, have been a little more in shape upon their release back into the wild.

The research has been published in Biology Letters.

Medications like Ozempic and Wegovy are famous for their weight loss benefits, but some scientists want to know more about how these drugs impact muscle loss.

In a new commentary for The Lancet, an international team warns there is not enough research on how muscles are affected by GLP-1 receptor agonists.

The authors acknowledge that GLP-1 agonists have "shown substantial benefits" for many people around the world. Initial studies find the medications, which were first approved to treat type 2 diabetes, can also make it easier to lose weight.

Even those who don't lose weight show improved kidney health and heart health, reducing their risk of stroke or cardiac arrest.

Despite all the good news, the scientists are concerned by preliminary results on GLP-1 agonists, which show slightly higher rates of non-fat tissue loss compared to weight loss from non-pharmacological means.

The loss of fat-free tissue may not be fully representative of muscle loss, nor is a loss of muscle mass necessarily a bad thing for strength or movement. But dietician Carla Prado, biomedical researchers Stuart Phillips and Steven Heymsfield, and nutritionist Cristina Gonzalez say we can't know for sure without further evidence.

"At the time of writing, there are no data to establish whether treatment with GLP-1 receptor agonists is associated with physical frailty or [a loss of muscle mass]," the team writes.

"These effects would require long-term studies, which are not yet available, and the studies conducted to date were not designed to answer these questions."

While initial studies suggest strength is not impacted by the weight loss associated with GLP-1 agonists, the authors note that strength "is only one aspect of muscles' importance."

Beyond movement, they explain, muscles play crucial roles in our body's metabolism, our immune function, and in our response to stress and trauma.

Besides all of that, muscle mass also helps the body take up glucose in response to insulin.

The researchers worry that muscle loss could be further exacerbating risk factors associated with GLP-1 agonists in some patients, such as metabolic dysfunction, inflammation, poor dietary intake, and low physical activity.

Given the risks, the authors conclude that "these highly effective medications should be used strategically. This strategy can be accomplished with concurrent nutrition and exercise interventions."

Studies have shown that after weight loss, a decrease in skeletal muscle mass can be partly mediated through increased protein intake or exercise. By some estimates, resistance exercise can actually attenuate losses in fat-free mass by 50 to 95 percent.

Such results add weight to the idea that exercise programs and nutritional advice should be prescribed alongside GLP-1 agonists for the best results.

Typically, once a person stops taking these appetite-suppressing medications, they regain about two-thirds of their lost weight in a year. In a recent clinical trial, however, those who partook in supervised exercise programs did better at maintaining their weight loss.

"Additionally," the team writes, "ongoing studies are exploring ways to prevent or mitigate muscle loss with drugs… which could offer solutions for preserving muscle mass in individuals undergoing weight loss treatments."

The potential for muscle loss doesn't mean patients should stop taking GLP-1 agonists, but given how important muscles are for human health, the researchers argue we need to know more.

The commentary was published in The Lancet: Diabetes & Endocrinology.

One bizarre marine creature has taken this approach to dire situations quite literally, regressing its physical adult body to a juvenile stage once the stress of starvation or injury has subsided.

Until now, the immortal jellyfish (Turritopsis dohrnii) was the only species thought to be able to wind back the clock on jelly-puberty like this, but now it's joined by Mnemiopsis leidyi, better known as the sea walnut or the warty comb jelly.

We already knew comb jellies were pretty special: Their regeneration abilities are unmatched, they can fuse together to survive major injuries, they only form a butthole when they actually need it, and with total disregard for the usual rules of biology, they can reproduce sexually in their so-called larval stage.

Previous studies had also observed M. leidyi reducing its size and body mass considerably during starvation as a way of surviving leaner times, but experiments ruled out reverse-aging under these conditions.

Marine biologist Joan Soto-Angel, from the University of Bergen in Norway, was confused when an adult sea walnut he was keeping in a laboratory tank, with its plump gelatinous lobes that define adulthood in this species, suddenly disappeared. In its place pulsed a larva, more walnut-shell-shaped than any adult of its kind.

He sensed the existing research might not be the full story, and so in collaboration with Michael Sars Center colleague, Pawel Burkhardt, set out to check whether this jelly had somehow pressed rewind on aging.

They kept 65 healthy adult comb jellies isolated in tanks, all of which had completely reabsorbed the tentacles of their youth, another defining feature of their maturity.

All were starved for 15 days, and then fed once a week with a small amount of rotifers, a much leaner diet than usual, and as expected, began to quickly shrink.

When their adult lobes began to 'reabsorb' into their diminishing bodies, feeding was resumed every second day. And Soto-Angel knew he was onto something.

Fifteen of these jellies also had lobes surgically removed at the start of the experiment, adding a further stressor that the previous experiments hadn't captured.

"Over several weeks, they not only reshaped their morphological features, but also had a completely different feeding behavior, typical of a cydippid larva," Soto-Angel says.

"Witnessing how they slowly transition to a typical cydippid larva, as if they were going back in time, was simply fascinating."

The experiment showed the jellyfish could revert to a youthful form when stressed only by starvation, but this was far less common than in the lobectomy group: Only seven of the 50 starved jellies fully reverted, while six out of the fifteen injured animals were the jelly equivalent of '17 again'.

This also means many of the juvenile jellies in experiments and records might not have been as youthful as they seemed.

"It will be interesting to reveal the molecular mechanism driving reverse development, and what happens to the animal's nerve net during this process," says collaborator Pawel Burkhardt, who is leading investigations into the evolutionary origins of neurons.

"The fact that we have found a new species that uses this peculiar 'time-travel machine' raises fascinating questions about how spread this capacity is across the animal tree of life," Soto-Angel says.

This research was published in Proceedings of the National Academy of Sciences.

In August 2017, humanity observed a wonder. For the first time, we got to see two neutron stars colliding, an event observed by telescopes around the world, alerted by the gravitational ruckus as the two objects spiraled in to merge and form a black hole.

Even at the time, we knew that that one event, a kilonova explosion named AT2017gfo, would give us sufficient scientific data to gnaw on for years to come. And so it has proven. Now, scientists have pieced together data from multiple telescopes to reconstruct the days after the kilonova took place, and its violently expanding fireball that gave birth to a flurry of heavy elements.

It's an event that evolved, says a research team led by astrophysicist Albert Sneppen of the Niels Bohr Institute at the University of Copenhagen, much like the Big Bang, with a hot soup of particles that cooled and coalesced into matter.

"This astrophysical explosion develops dramatically hour by hour, so no single telescope can follow its entire story. The viewing angle of the individual telescopes to the event are blocked by the rotation of the Earth," Steppen explains.

"But by combining the existing measurements from Australia, South Africa, and the Hubble Space Telescope we can follow its development in great detail. We show that the whole shows more than the sum of the individual sets of data."

One fascinating thing that the observations of AT2017gfo showed was the creation of heavy elements. A lot of elements are forged inside stars, where core fusion processes smash atoms together to make heavier ones.

But there's a cutoff point for this – stars can't fuse elements heavier than iron, because the energy it takes to do so is greater than the energy produced by fusion.

It takes a very energetic event to make heavier elements, such as a supernova explosion. AT2017gfo showed that neutron star kilonovae are also productive heavy element factories – in the light emitted during the explosion, astronomers detected the signature of strontium.

Steppen and his colleagues have taken this analysis a step further. By carefully studying multiple datasets, they were able to observe the hour-by-hour evolution of the kilonova, and the formation of heavy elements, known as r-process elements, within.

When the two neutron stars collide, the initial kilonova of exploded neutron star guts is extremely hot, billions of degrees, comparable to the heat of the Big Bang. In this hot, plasmatic environment, elementary particles like electrons can whizz around freely, unbound.

As the kilonova expands and cools, the particles snatch each other up and become atoms. This, the researchers say, is similar to a period early in the history of the Universe known as the Epoch of Recombination.

Around 380,000 years after the Big Bang, the Universe cooled enough so that the particles glopping around in the primordial plasma soup could combine into atoms. The plasma soup had scattered light instead of allowing it to propagate, and this 'recombination' meant that light could finally stream through the Universe.

The process of combination observed in the neutron star kilonova is very similar to what we think happened during the Epoch of Recombination, suggesting that kilonovae could be a powerful laboratory for probing the evolution of the early Universe, in miniature.

The researchers were also able to confirm the presence of strontium and yttrium in the evolving kilonova, bolstering support for kilonova explosions as a source of heavy elements in the Universe.

"We can now see the moment where atomic nuclei and electrons are uniting in the afterglow," says astrophysicist Rasmus Damgaard of the Niels Bohr Institute.

"For the first time we see the creation of atoms, we can measure the temperature of the matter and see the micro physics in this remote explosion. It is like admiring three cosmic background radiation surrounding us from all sides, but here, we get to see everything from the outside. We see before, during and after the moment of birth of the atoms."

Now that's metal.

The research has been published in Astronomy & Astrophysics.

From all over the sky, the Universe is hurling mysterious signals.

We don't really know what they are, or what's making them; but a new analysis of where they are coming from gives us clues about the sources of the strange emissions we call fast radio bursts (FRBs).

Led by astronomer Kritti Sharma of the California Institute of Technology, an international team conducted a census and determined that FRBs are more likely to come from galaxies with relatively young star populations. This is somewhat expected. What the researchers didn't expect was that those galaxies were more likely to be quite large, with large numbers of stars – which are actually pretty rare.

This suggests that there might be something unusual about the way FRBs are generated.

We already have some pretty good ideas about what FRBs are. First, a description: they are very powerful but very brief emissions of radio light that last from fractions of a millisecond to several seconds. They come from all across the sky, their sources millions to billions of light-years away often seeming to flash once and never again.

This makes them impossible to predict and difficult to trace, but we're getting better at detection with wide-view surveillance, and better at locating their host galaxies, too.

As for what they are, we're homing in on that too. Spoiler: it's not aliens. Rather, the first FRB detected right here in the Milky Way back in 2020 was traced to a magnetar – a type of neutron star that has a magnetic field 1,000 times more powerful than an ordinary neutron star's. The push-pull interaction between the magnetic field and the object's gravity can create starquakes that send radio light flashing across the sky.

Not all FRBs behave the same, so it's possible that there is more than one kind of source. Narrowing down where those sources sit tells us something about the environmental conditions that are most likely to produce them, which in turn allows us to make inferences about what they are.

Sharma and her colleagues collected observations using a radio interferometer called the Deep Synoptic Array in a new effort to detect FRBs and localize them. They carefully studied the properties of 30 FRB host galaxies, and determined that the radio bursts typically emerge from galaxies with populations of young stars.

This is not surprising if FRB progenitors are magnetars. Neutron stars are the collapsed cores of massive stars that have gone supernova via core collapse, and massive stars have shorter lifespans than smaller ones. Magnetars are young neutron stars, so we expect to find them in places where most of the stars are young and have short lives.

Although some FRBs have previously been detected in populations of old stars, and in low-mass galaxies, the team's analysis showed that the most common progenitors by far are high-mass galaxies with young stars. This suggests that massive, young stellar environments are important for the formation of FRB progenitors; if they were not, we'd see a broader distribution across galaxy types.

Why this might be is unknown, but the researchers believe that the metallicity of these massive star-forming galaxies might play a role. Massive galaxies typically have a much higher metal content than lower-mass counterparts, and tend to make heavier stars, too.

But there's another problem. Core-collapse supernovae take place at a rate similar to the rate of star formation in the Universe. If the magnetars that produce FRBs form in this way, the distribution of FRBs should be broadly consistent with the distribution of core-collapse supernovae, even for low mass galaxies – but it isn't. This suggests that magnetars that form via core collapse are not the main FRB progenitor.

The team conducted simulations, and found a solution. The magnetars that emit FRBs could form from binary star mergers. This is more likely to occur in environments with more massive stars, such as the galaxies the researchers identified.

We still don't have a holistic explanation for the origins of FRBs, but the research significantly strengthens the case for magnetars, and suggests that special circumstances for the formation of those magnetars are also at play.

The study of FRBs is still progressing, but astronomers are discovering more of the strange signals constantly. The more we find, the more data we will be able to crunch to resolve the mystery of FRBs' origins. It's a tremendously exciting time to be alive and studying the stars.

The research has been published in Nature.

The risk of getting dementia may go up as you get older if you don't get enough slow-wave sleep. Over-60s are 27 percent more likely to develop dementia if they lose just 1 percent of this deep sleep each year, a 2023 study found.

Slow-wave sleep is the third stage of a human 90-minute sleep cycle, lasting about 20–40 minutes. It's the most restful stage, where brain waves and heart rate slow and blood pressure drops.

Deep sleep strengthens our muscles, bones, and immune system, and prepares our brains to absorb more information. Recently, research discovered that individuals with Alzheimer's-related changes in their brain did better on memory tests when they got more slow-wave sleep.

"Slow-wave sleep, or deep sleep, supports the aging brain in many ways, and we know that sleep augments the clearance of metabolic waste from the brain, including facilitating the clearance of proteins that aggregate in Alzheimer's disease," said neuroscientist Matthew Pase from Monash University in Australia.

"However, to date we have been unsure of the role of slow-wave sleep in the development of dementia. Our findings suggest that slow-wave sleep loss may be a modifiable dementia risk factor."

Pase and colleagues from Australia, Canada, and the US examined 346 Framingham Heart Study participants who had completed two overnight sleep studies between 1995 and 1998 and between 2001 and 2003, with an average of five years between testing periods.

This community-based cohort, who had no record of dementia at the time of the 2001-2003 study, and were over 60 years old in 2020, gave researchers a chance to look into the link between two factors over time by comparing the datasets from the two in-depth polysomnography sleep studies, and then monitoring for dementia among participants up until 2018.

"We used these to examine how slow-wave sleep changed with aging and whether changes in slow-wave sleep percentage were associated with the risk of later-life dementia up to 17 years later," said Pase.

In the 17 years of follow-up, 52 dementia cases were recorded among the participants. Participants' slow-wave sleep levels recorded in the sleep studies were also examined for a link to dementia cases.

Overall, their rate of slow-wave sleep was found to decrease from age 60 onward, with this loss peaking between the ages of 75 and 80 and then leveling off after that.

By comparing participants' first and second sleep studies, researchers discovered a link between each percentage point decrease in slow-wave sleep per year and a 27 percent increased risk of developing dementia.

That risk increased to 32 percent when they zeroed in on Alzheimer's disease, the most common form of dementia.

The Framingham Heart Study measures multiple health data points over time, including hippocampal volume loss (an early sign of Alzheimer's) and common factors contributing to cardiovascular disease.

Low levels of slow-wave sleep were linked to a higher risk of cardiovascular disease, taking medications that can impact sleep, and having the APOE ε4 gene, which is linked to Alzheimer's.

"We found that a genetic risk factor for Alzheimer's disease, but not brain volume, was associated with accelerated declines in slow wave sleep," Pase said.

Although these are clear associations, the authors note this type of study doesn't prove that slow-wave sleep loss causes dementia, and it's possible dementia-related brain processes cause sleep loss. For these factors to be fully understood, more research is required.

We certainly can prioritize getting enough sleep in the meantime – it's important for more than strengthening our memory. There's even steps you can take to boost your chances of getting more of this crucial slow-wave sleep.

The study has been published in JAMA Neurology.

An earlier version of this article was published in November 2023.

For centuries, the faithful and the curious have crowded to gaze up at the Sistine Chapel's ceiling in awe of Michelangelo Buonarroti's reimagining of scenes from Genesis.

Few, if any, may have noticed that one among the 300 figures was destined to soon die.

A detailed investigation of a woman's breast painted on the second span of the vault has concluded its unusual features represent advanced breast cancer, a disease the artist not only would have been aware of, but intentionally chose to depict.

The international team of experts provided insights from a variety of disciplines, combining their knowledge of art history, medicine, and genetics to diagnose the state of health of a fictitious, semi-naked woman in a scene depicting the biblical flood and propose reasons for her presence.

Commencement on the chapel ceiling began in 1508 on order by Pope Julius II, taking four years in total to complete its numerous scenes from the Old Testament, images of prophets, and representations of other noted biblical events.

Michelangelo was a seasoned artist in his thirties when he reluctantly agreed to take on the immense task, bringing years of experience sculpting anatomy and capturing extraordinary levels of detail in his subjects.

With that in mind, observations of what appeared to be a deformity in the left breast of one of the figures couldn't be easily dismissed as an accidental smudge from an amateur hand.

To the lay viewer, the woman is just one in a crowd of fatigued bodies escaping the rising waters sent by God to cleanse the world of sin. To art historians, the blue color of the headscarf is a sign of her married status, her finger gesturing at the earth suggesting her return to dust was imminent.

Medical experts focused their attention on the left breast, shaped by age and motherhood, with a shading indicative of retracted skin around the areolar region, and subtle swellings in the upper quarter and near the armpit. Were it a photograph in a case file, the characteristics would all be strongly suggestive of breast cancer.

Breast cancer in relatively young subjects as this could be explained by an inheritance of high-risk genes, some of which have been traced back centuries in Europe.

Comparing the details with features of the woman's other breast, along with those on numerous other figures in the painting, the team was confident the design was unique enough to be intentional.

Over the centuries, the ceiling has undergone numerous interventions and restorations in an attempt to preserve its color and detail, including a major rework in the late 20th century. Comparisons of photographs taken of the scenes in the past make it clear the original shape and shading of the breasts haven't changed substantially.

Michelangelo was no stranger to death and disease. Unlike many contemporary artists who honed their craft by studying living models, he had participated in dissections since his teens, gaining an appreciation of how the body operated on a mechanical level.

The researchers refute suggestions the artist authentically copied the pathology from a model with breast cancer – or even a male model transformed with ill-fitting anatomy.

"Michelangelo did not resort to a living model (or living models either male or female) when depicting the story of the Genesis," the team writes.

"No realistic portraits are presented in the scene. It is rather the composition of an idea based upon the story of the Bible with idealized faces and bodies."

This may not even be Michelangelo's only depiction of the disease. Years later he would carve a feminine representation of the night for the tomb of Giuliano de' Medici with a similarly distorted breast, catching the eye of oncologists back in 2000.

If inflictions of breast cancer were subtly painted into the masterpiece with consideration, what would be the purpose?

"The representation of a probable breast cancer is linked to the concept of the impermanence of life and has the significance of punishment," the researchers suggest.

An embodiment of sin in the form of a deadly disease, the symbol in the Sistine Chapel has gone unappreciated by many for so long. Centuries on, Michelangelo's unique gift for understanding the human body continues to astonish.

This research was published in The Breast.

In the binary system 4U 1820-30, a neutron star is spinning so fast around its center axis that it completes a breathtaking 716 rotations per second. No stars have been discovered spinning faster, and only the famous pulsar PSR J1748-2446ad has been found spinning at that speed.

This discovery, says a team led by astrophysicist Gaurava Jaisawal of the Technical University of Denmark, affirms the current theoretical upper limit for neutron star spin speeds, thought to be around 730 rotations per second.

"We were studying thermonuclear explosions from this system and then found remarkable oscillations," Jaisawal says.

"If future observations confirm this, the 4U 1820-30 neutron star would be one of the fastest-spinning objects ever observed in the Universe."

Neutron stars are one of the evolutionary final stages in the lifespan of a massive star.

Once a star between around 8 and 30 times the mass of the Sun has run out of atoms it can fuse in its core; it goes kaboom (or maybe it doesn't), ejecting its outer material in a supernova explosion, while the core, no longer supported by the outward pressure supplied by fusion, collapses under gravity.

That collapsed core is the neutron star, an object between around 1.1 and 2.3 times the mass of the Sun, packed into a tiny sphere just 20 kilometers (12 miles) across. 'Dense' doesn't begin to cover it. Matter inside these things can get weird – and so can their behavior.

We have different names to classify this behavior. A magnetar is a neutron star with an insanely powerful magnetic sphere. And a pulsar is a neutron star spinning incredibly fast, blasting out beams of radio waves from their poles so they appear to 'pulse' in space like a cosmic lighthouse.

We've known 4U 1820-30 exists since at least the 1980s. It's a binary star system in the constellation of Sagittarius that includes a neutron star and a white dwarf star, on a really tight orbit with a period of just 11.4 minutes.

The proximity of the two stars means the neutron star is close enough to cannibalize its companion, stripping it of material that then accumulates on the neutron star's surface.

This accumulation of mass becomes denser and hotter the more it accrues, until eventually the star sneezes it off in a thermonuclear explosion.

It was these explosions that Jaisawal and his colleagues were trying to study, using NASA's Neutron Star Interior Composition Explorer (NICER), an X-ray telescope catching a ride with the International Space Station.

"During these bursts, the neutron star becomes up to 100,000 times brighter than the sun, releasing an immense amount of energy," says astrophysicist Jerome Chenevez of the Technical University of Denmark.

"So we are dealing with very extreme events, and by studying them, we get new insights into the existing life cycles of binary star systems and the formation of elements in the Universe."

The team recorded 15 of these thermonuclear blasts between 2017 and 2022. But when they were analyzing the data, they found something strange. One of the blasts had an odd signature, an oscillation with a frequency of 716 Hertz. It was as though the star was rotating as it erupted – which, the researchers determined, was likely the case.

This could mean that the 4U 1820-30 neutron star is an X-ray pulsar, with a period of 716 rotations per minute, powered by thermonuclear explosions. Since PSR J1748-2446ad is a radio pulsar, this would make 4U 1820-30 the fastest known nuclear-powered pulsar.

More observations will be required to verify this finding. If confirmed, however, the results will give us a new tool for studying neutron stars, and the extremities they can reach before they self-destruct.

The team's research has been published in The Astrophysical Journal.

If you're looking for an exercise routine that can help you lose weight, you might want to increase the intensity of your workouts: a new study shows that vigorous exercise is better for suppressing appetite than moderate exercise.

The study comes from researchers at the University of Virginia, and involved 14 healthy participants. They were asked to fast overnight, before completing a variety of exercises at different levels of intensity, and then reporting on their appetite levels.

Blood samples were also taken to measure the effects of exercise on the hormone ghrelin, known to play a significant role in regulating appetite. The higher the levels of ghrelin in the body overall, the hungrier we feel.

"We found that high-intensity exercise suppressed ghrelin levels more than moderate-intensity exercise," says endocrinologist Kara Anderson, from the University of Virginia.

"In addition, we found that individuals felt less hungry after high-intensity exercise compared to moderate intensity exercise."

The difference in ghrelin levels was most significant in female participants, the researchers found, though in terms of self-reported appetite levels there were noticeable drops across both sexes after higher intensity exercises.

Ghrelin can be found in both acylated (AG) and deacylated (DAG) forms in the body, and as well as being linked to appetite, it's also important in other areas, including sleep, memory, and energy balance.

The researchers suggest that there's a specific point at which ghrelin starts diminishing – possibly when the body is producing more lactate than it can handle. Lactate is a byproduct of muscle metabolism that is produced as the body works harder.

"As our protocol utilized blood lactate to determine exercise intensities, these findings suggest that exercise above the lactate threshold may be necessary to elicit a suppression in ghrelin," write the researchers in their published paper.

The relationship between exercise and appetite is actually a pretty complicated one: depending on the type of workout, how long it lasts for, and the profile of the people involved, exercise can both increase and decrease hunger levels.

It's one of those areas where more research is definitely needed – which was part of the aim of this new study. While the study sample was small, it does highlight potential differences between the sexes when it comes to the ghrelin hormone.

As for weight loss, we know that the ability to shed the pounds depends on a whole host of factors – including exercise routines – and that we're all different when it comes to what tactics work best, something this new research sheds more light on.

"Exercise should be thought of as a drug, where the dose should be customized based on an individual's personal goals," says Anderson.

"Our research suggests that high-intensity exercise may be important for appetite suppression, which can be particularly useful as part of a weight loss program."

The research has been published in the Journal of the Endocrine Society.

A buzz of clicks and gleeful victory squeals compose the soundtrack in the first footage ever recorded from the perspective of dolphins freely hunting off the coast of North America.

For a scientific study published in 2022, the US Navy strapped cameras to dolphins, which are trained to help identify undersea mines and protect some of America's nuclear stockpile, then gave them free rein to hunt in San Diego Bay.

The clever marine mammals did not disappoint, offering up exciting chases and even targeting venomous sea snakes to the surprise of the researchers.

For such popular, well-known animals, there are still so many basic things we don't yet know about these highly social and often gross cetaceans, like precisely how they typically feed.

Researchers broadly know of at least two techniques: slurping up prey like noodles from a bowl, and ramming them down like a hot dog between rides at a state fair.

But the footage revealed a whole lot more.

The cameras, strapped to six bottlenose dolphins (Tursiops truncatus) from the US National Marine Mammal Foundation (NMMF), recorded six months of footage and audio – providing us with a new level of insight into these mammals' hunting strategies and communications.

The recording equipment was placed on their backs or sides, displaying disturbingly odd angles of their eyes and mouths.

While these dolphins aren't wild, they are provided with regular opportunities to hunt in the open ocean, complementing their usual diet of frozen fish. So it is likely these animals use similar methods to their wild brethren, as NMMF marine mammal veterinarian Sam Ridgway and colleagues explained in 2022.

"As dolphins hunted, they clicked almost constantly at intervals of 20 to 50 milliseconds," they report in their paper.

"On approaching prey, click intervals shorten into a terminal buzz and then a squeal. On contact with fish, buzzing and squealing was almost constant until after the fish was swallowed."

The camera-strapped dolphins caught more than 200 fish, including bass, croakers, halibut, smelt and pipefish. The smelt often flung themselves into the air in desperate attempts to escape the skilful predators.

But the dolphins tracked their every move, swimming upside down to give their swiveling eyes a clear view – a technique also observed previously in wild dolphins.

"These dolphins appeared to use both sight and sound to find prey," Ridgway and colleagues explained. "At distance, the dolphins always used echolocation to find fish. Up close, vision and echolocation appeared to be used together."

The cameras also recorded the sound of the animals' hearts as they pumped hard to keep up with the strenuous activities, and revealed that rather than ramming their victims down, the dolphins instead used suction to help gulp down their still struggling prey with impressively strong throat muscles.

The dolphins mostly sucked fish in from the sides of their open mouths, throat muscles expanded and tongue withdrawn out of the way. The expanded inner mouth space helps create negative pressure that their sucking muscles add to.

While dolphins have been caught messing around with snakes before, including river dolphins playing with an absurdly large anaconda, the footage confirmed for the first time that they may also eat these reptiles too.

One dolphin consumed eight highly venomous yellow-bellied sea snakes (Hydrophis platurus).

"Our dolphin displayed no signs of illness after consuming the small snakes," the researchers explained, but they acknowledged this could also be unusual behavior since the dolphins are captive animals.

"Perhaps the dolphin's lack of experience in feeding with dolphin groups in the wild led to the consumption of this outlier prey."

The lead author of the study, Sam Ridgway, passed away at age 86, shortly before the study was published, leaving behind a rich legacy of research.

"His creative approach to partnering with Navy dolphins to better understand the species' behavior, anatomy, health, sonar, and communication will continue to educate and inspire future scientists for generations," NMMF ethologist Brittany Jones told The Guardian.

As for the Navy-trained dolphins, they "work in open water almost every day", NMMF explains on their website.

"They can swim away if they choose, and over the years a few have. But almost all stay."

This research was published in PLOS ONE.

An earlier version of this article was published in August 2022.

We already know that the virus behind cold sores, herpes simplex virus type 1 (HSV-1), can also infect the brain and the central nervous system, and now a new study sheds more light on how the viral attack spreads out.

Led by researchers from the University of Colorado and the University of Bourgogne in France, the study took a close look at the effects of the HSV-1 virus on the brains of mice, mapping out the different regions affected and assessing what the consequences might be.

HSV-1 can be introduced to the central nervous system through two routes – the trigeminal nerve or the olfactory nerve – although it remains unclear how the infection then spreads within the brain.

"Recently, this common virus has been implicated in neurodegenerative diseases, such as Alzheimer's disease, but no clear route of central nervous system invasion has been established," says neurologist Christy Niemeyer from the University of Colorado.

"Identifying how HSV-1 can get into the brain and what brain regions are vulnerable is key in understanding how it initiates disease."

The team found that HSV-1 took hold in several of the brain's most important regions, including the brain stem (responsible for co-ordinating heart and breath rate, along with sleep and movement), and the hypothalamus (which handles everything from sleep and moods to appetite and hormone levels).

However, other areas of the brain remained untouched by HSV-1 antigens, including the hippocampus (the region that looks after memory and special navigation, often connected to diseases like Alzheimer's) and the cortex (linked to memory and attention).

The researchers also looked at the activity of microglia (in-house immune cells of the central nervous system) in the mouse brains, which became inflamed when interacting with HSV-1. In certain regions, these immune cells stayed busy even after the virus had gone, suggesting ongoing inflammation.

In the most serious cases, HSV-1 can cause encephalitis, a life-threatening condition where inflammation affects the whole brain. While this didn't happen here, the research shows there might still be damage being done.

"Even though the presence of HSV-1 is not causing full-blown encephalitis in the brain, it can still affect how these regions function," says Niemeyer.

All of this additional knowledge gives scientists a better idea of how HSV-1 infections might be related to neurodegenerative diseases – something which has been the subject of several recent studies. The new study is another useful step forward that further research can now build on.

It's been suggested that HSV-1 and microglia-related inflammation could be part of the reason why Alzheimer's takes hold in some brains, or they may have some effect on its rate of progress. With that in mind, it's interesting to see where there's overlap in the brain regions affected by both HSV-1 and Alzheimer's.

"Persistently inflamed cells can lead to chronic inflammation, a known trigger for a number of neurological and neurodegenerative diseases," says Niemeyer.

"This research offers important takeaways in better understanding how viruses interact with overall brain health as well as the onset of pervasive neurological diseases."

The research has been published in the Journal of Virology.

Sold under the brand names Ozempic and Wegovy, the diabetes-treatment drug semaglutide is also proving incredibly effective in the management of weight loss.

Health problems attributed to obesity might also be expected to ease following treatment, though evidence of the drug's effectiveness on conditions such as knee pain is limited.

In a phase 3 clinical trial involving 407 participants, an international team of researchers found that a weekly dose of 2.4 milligrams of semaglutide significantly beat placebo treatments for reducing weight and relieving symptoms of obesity-related osteoarthritis over a 68 week period, improving the ability to complete physical activities like walking.

For some, the pain reduction was so drastic that they were effectively "treated out of the study", as rheumatologist Henning Bliddal from Copenhagen University Hospital in Denmark told Traci Watson at Nature.

The arthritic condition is brought on when the protective cartilage in the knee joints gets worn away, causing pain and stiffness that can be quite severe. Obesity is a major risk factor for knee osteoarthritis, and losing weight can help reduce the pain – two good reasons why the researchers wanted to investigate the potential benefits of semaglutide.

Semaglutide is what's known as a glucagon-like peptide-1 receptor agonist (GLP-1RA), which mimics the GLP-1 hormone that gets produced when we eat, tricking the brain into thinking we're full.

The drug has been proven effective for helping individuals lose weight, which in principle might ease the load on sore knees and even assist in the tissue's recovery. But preclinical studies also suggest GLP-1RAs may also work as an anti-inflammatory, potentially calming immune responses that trigger swelling and tissue damage.

On average, body weight dropped 13.7 percent in the group given semaglutide compared to 3.2 percent given placebos, while the reported pain scores dropped 41.7 points and 27.5 points respectively (the pain scale used runs from 0 to 96).

There are a few caveats to consider. The study was partly funded by Novo Nordisk, which manufactures semaglutide. Also, while participants were given advice about diet and physical activity routines during the trial, there were no checks on how much of this advice was followed.

It's also worth bearing in mind that semaglutide in its various forms is an expensive drug, and that weight can quickly pile back on when doses are stopped. Getting people to take the drug long term could be challenging.

Despite those issues, the study results offer plenty of early promise for a future treatment for knee osteoarthritis and the debilitation that goes along with it. There are treatments currently available, but they often come with limitations or side effects.

Those with the condition are often caught in a bind: knowing that physical activity and exercise can help them lose weight and improve their symptoms, but also being in too much pain to actually do anything about it. It's a ray of hope for the hundreds of millions of people living with knee osteoarthritis.

"Weight reduction along with physical activity is often a recommended approach to managing painful symptoms, but adherence can be challenging," says Biddal.

The research has been published in the New England Journal of Medicine.

We know that the tiny tardigrade is one of the toughest creatures on the planet, and a newly discovered species of these miniature 'water bears' has given experts a deeper insight into how they can withstand harmful radiation.

When researchers from multiple institutions across China looked closely at the genome of the new species – Hypsibius henanensis – discovered six years ago, they discovered 14,701 protein-coding genes, of which 4,436 (30.2 percent) were unique to tardigrades.

They also exposed the small creatures to blasts of radiation, watching to see how gene expression and protein production would be affected – and the sort of biological superpowers these genes might provide for the tardigrades.

"Studies on several tardigrade species have documented that they are the most radiation-tolerant animals on Earth," write the researchers in their published paper.

"They exhibit resistance to gamma radiation of up to 3,000 to 5,000 grays (Gy), around 1,000 times higher than the lethal dose for humans."

The team made three key observations: a gene called DODA1, potentially transferred from bacteria, produces pigments known as betalains, and these help to neutralize the harmful molecules that are generated by radiation.

Second, DNA was being repaired much more quickly than normal, thanks to a tardigrade-specific protein called TRID1, and third, production increased of two other proteins, BCS1 and NDUFB8 (which also help with energy supply).

While some of these tricks were already known about, like high-speed DNA repair, the close analysis of H. henanensis gives us more detail about what exactly is going on – and how the humble tardigrade stays so robust.

Combined together, these three processes that emerge in response to radiation help to protect the tardigrades against its dangerous effects. The next step is to see how generally these protective measures are deployed across all tardigrade species.

"Whether the radiation tolerance of other tardigrade species occurs through conserved mechanisms or is specific in the genus Hypsibius warrants additional study," write the researchers.

There are around 1,500 species of tardigrade that we know about, and the new study matches previous research into Hypsibius exemplaris tardigrades: when radiation is detected, the creatures ramp up the activity of repair genes.

And these findings go way beyond the tardigrade. As small as it is, the ways this animal can cling to life are helpful in figuring out how to better protect our own bodies in extreme environments (not least during long-term space flights, for example).

It's thought that tardigrades first appeared before the Cambrian, which is around 541 million years ago. To survive that long, you need to have plenty of tricks at your disposal for staying alive.

"The capability of tardigrades to survive under the harshest conditions continues to reshape our concept of the limits of animal life on Earth," write the researchers.

The research has been published in Science.

For the first time, we've got a three-dimensional picture of a magnetic skyrmion. This tiny, spiraling flaw in the magnetic properties of some materials could find uses in next-gen electronics storage devices and quantum computers.

While two-dimensional predictions of skyrmions have proved valuable, new research from the US and Switzerland shows the particle-like swirls aren't confined to flat surfaces. They're more complex, making determining their 3D structure important.

The new study, led by physicist David Raftrey from the Lawrence Berkeley National Laboratory in California, gives us a better understanding of the fundamentals of magnetic materials. Considering how widely they are used, there are many potential applications.

"The presence of skyrmions or other magnetic textures at the microscopic level fundamentally determines the properties, behavior, and functionality of magnetic materials," the team writes in their published paper.

At the nanoscale, in certain magnetic materials, skyrmions can be found as stable, standing waves consisting of swirls of contrasting electron spins. These swirls can be triggered to move in particular ways, through the application of an electric charge or a magnetic field.

Raftrey and his colleagues used an advanced technique called magnetic X-ray laminography – a process akin to medical CT scans for simpler materials. As an object is moved and rotated, new readings are taken, building up a 3D picture.

In this case, the object was a very small magnetic disk containing skyrmions, just 800 nanometers across and 95 nanometers thick. Stack around a thousand of them on top of each other, and you're up to the thickness of a standard piece of paper.

This wasn't a quick process – taking months overall – but the researchers eventually came up with the improved understanding of skyrmion spin structures they were looking for, thanks to the use of some sophisticated algorithms to combine the X-ray images.

"You can basically reconfigure and reconstruct [the skyrmion] from these many, many images and data," explains Raftrey.

Now that these structures have been mapped in 3D for the first time, we know how they are shaped, how they interact, and how they vary layer-by-layer – a big improvement on the 2D images we had previously.

What physicists like about skyrmions is that they're very stable, very speedy, and very difficult to break up. That suggests they might be useful for storing the 1s and 0s of basic data in a more compact and efficient way than traditional approaches do.

It's a field of science known as spintronics, using electron spins instead of electrons as the foundation of computing systems. As previous studies have shown, it would mean major jumps forward in computer size and miniaturization.

"Relying on the charge of the electron, as it is done today, comes with inevitable energy losses. Using spins, the losses will be significantly lower," says materials scientist Peter Fischer from the Lawrence Berkeley National Laboratory.

"Our results provide a foundation for nanoscale metrology for spintronics devices."

The research has been published in Science Advances.

Early in the life of the Solar System, things were a lot more violent than they are today. Rocks were flying everywhere, willy-nilly, smacking into the newly formed planets, pocking them with craters and gouging out impact basins.

Mercury, Mars, and the Moon are all heavily scarred. Even Earth – where geological and weathering processes quickly erode most of the evidence – shows signs of giant impacts.

But there's something really weird about Venus.

Though the hellish world has beautifully preserved impact craters on its surface, scientists could find no evidence of craters more than 300 kilometers (186 miles) across, otherwise known as impact basins.

Now, that evidence has emerged. It just doesn't look the way we expected it to – which could give us new clues about Venus' formation and evolution, back when the Solar System was young.

That evidence is a feature known as tessera terrain; a series of concentric rings on the surface of Venus some 1,500 kilometers across. New analysis suggests Venus's Haastte-Baad Tessera was the result of two giant impacts, one right after the other, with a planet that was still mooshy and molten beneath a thin crust, some 3.5 billion years ago.

"If this is really an impact structure it would be Venus' oldest and largest, giving us a rare glimpse into Venus' past and informing early planet processes," says geologist Vicki Hansen of the Planetary Science Institute.

"And perhaps even more important, it shows us that not all impact structures look alike. Impact structures result from a bolide – a body of unspecified composition – that collides with a target planet. The nature of the bolide is important, but so too is the nature of the target."

When the rocky planets were newly formed, they were much warmer inside than they are now, their molten interiors making up more of their volume beneath a far thinner crust. Hansen and her colleagues performed modeling analysis to study the formation processes that could have produced the Haastte-Baad Tessera, and determined that a double impact was the most plausible scenario.

Two impactors, back-to-back, would have punched right through the 10-kilometer-thin crust on the Venusian surface, and splooshed into the molten mantle below. Magma would have bubbled up to the surface, and the surrounding surface crumpled to form the concentric tessera pattern.

We know that this process can happen because we've seen it elsewhere in the Solar System. On Jupiter's moon Callisto is a multi-ring structure some 3,800 kilometers across. This is Valhalla, the largest known multi-ring impact structure in the system, and scientists believe that it was formed when something large smacked into the icy moon. Frigid water surged from below to fill the hole, and the impact deformed the surrounding crust.

One potential problem with that model is that tessera terrain is sometimes found sitting on a plateau. That's not the case for Haaste-Baad, but the model needs to incorporate plateau settings; if an impact can't produce a tessera plateau, something else would have to be responsible for the ring structures.

"This is where it gets fun," Hansen explains.

"When you have vast amounts of partial melt in the mantle that rushes to the surface, what gets left behind is something called residuum. Solid residuum is much stronger than the adjacent mantle, which did not experience partial melting. What may be surprising is that the solid residuum is also lower density than all the mantle around it. So, it's stronger, but it's also buoyant. You basically have an air mattress sitting in the mantle beneath your lava pond, and it's just going to rise up and raise that tessera terrain."

If the lava stays put, it will harden in that raised position. If it drains away, the elevation of the terrain will sink down, as we see with Haastte-Baad.

The modeling suggests that the impactors that produced the terrain were pretty large, about 75 kilometers across, give or take. This seems to have been a pretty rare occurrence in the Solar System, but not unheard-of; there are geological features on Earth that may have formed the same way, such as a dike swarm at Lake Victoria in Africa.

"Who would have thought flat low-lying tessera terrain or a big plateau is what an impact crater could look like on Venus?" Hansen says.

"We had been looking for big holes in the ground, but for that to happen, you need a thick lithosphere, and early Venus didn't have that. Mars had a thick lithosphere. The Moon had a thick lithosphere. Earth likely had a thin lithosphere when it was young too, but its record has been greatly modified or erased by erosion and plate tectonics."

The research has been published in the Journal of Geophysical Research: Planets.

A supermassive black hole in the early Universe is the most voracious of its kind we've ever seen.

It's sitting in the middle of a galaxy called LID-568, as seen just 1.5 billion years after the Big Bang, appearing to guzzle down material at a jaw-dropping rate of over 40 times a theoretical maximum known as the Eddington limit.

We've never seen anything like it – and it's a discovery that could help us unravel one of the greatest mysteries of the early Universe: how supermassive black holes get so incredibly massive in such a short period of time following the Big Bang.

"This black hole is having a feast," says astronomer Julia Scharwächter of Gemini Observatory and NSF's NOIRLab. "This extreme case shows that a fast-feeding mechanism above the Eddington limit is one of the possible explanations for why we see these very heavy black holes so early in the Universe."

The Eddington limit is a natural consequence of the black hole feeding process. When a black hole actively accretes large amounts of material, that material doesn't fall straight into the gravity well, but first swirls like water circling a drain, with only the material at the inner edge of the disk crossing the horizon into the black hole.

The incredible amount of friction and gravity heats this disk of material to extremely hot temperatures, causing it to blaze with light. But the thing about light is that it exerts a form of pressure.

A single photon isn't going to do much, but the blaze of an active supermassive black hole accretion disk is another matter. At a certain point, the outward pressure of radiation matches the inward gravitational pull of the black hole, preventing material from moving closer. That's the Eddington limit.

Breaking the Eddington limit of accretion is possible. It's known as super-Eddington accretion, during which the black hole goes absolutely ham, slurping up as much mass as it can before radiation pressure takes over. This is one way astronomers believe supermassive black holes at the dawn of time could attain masses that defy easy explanation.

Led by astronomer Hyewon Suh of Gemini Observatory and NSF's NOIRLab, a team of researchers used JWST to take follow-up observations of a smattering of galaxies identified by the Chandra X-ray Observatory that were bright in X-rays but dim in other wavelengths.

When they got to LID-568, they were having trouble identifying its distance across space-time. The galaxy was very faint and very hard to see; but, using the integral field spectrograph on JWST's NIRSpec instrument, the team homed in on the galaxy's exact position.

LID-568's far-off location is surprising. Although the object is faint from our position in the Universe, its distance means it must be incredibly intrinsically bright. Detailed observations revealed powerful outflows from the supermassive black hole, a signature of accretion as some of the material is being diverted and blasted into space.

A painstaking analysis of the data revealed that the supermassive black hole is a relatively small one, as supermassive black holes go; just 7.2 million times the mass of the Sun. And the amount of light being produced by the material around the disk was much, much higher than a black hole of this mass should be capable of producing. It suggests an accretion rate some 40 times higher than the Eddington limit.

At this rate, the period of super-Eddington accretion should be extremely brief, which means Suh and her team were extremely lucky to catch it in action. And we expect that LID-568 will become a popular observation target for black hole scientists, allowing us a rare glimpse into super-Eddington processes.

In turn, this could help us understand the early Universe. There is evidence to suggest that the first supermassive black holes formed not from collapsing stars as we know them, but from huge stars and huge clumps of gas, directly collapsing under gravity. This would give them a headstart on their way to becoming the giant black holes we see in the Universe today. Bursts of super-Eddington accretion could be another piece of the puzzle.

"The discovery of a super-Eddington accreting black hole suggests that a significant portion of mass growth can occur during a single episode of rapid feeding," Suh says, "regardless of whether the black hole originated from a light or heavy seed."

The research has been published in Nature Astronomy.

An expedition to a deep-sea ridge, just north of the Hawaiian Islands, revealed a surprise discovery back in 2022: an ancient dried-out lake bed paved with what looks like a yellow brick road.

The eerie scene was chanced upon by the exploration vessel Nautilus, while surveying the Liliʻuokalani ridge within Papahānaumokuākea Marine National Monument (PMNM).

PMNM is one of the largest marine conservation areas in the world, larger than all the national parks in the United States combined, and we've only explored about 3 percent of its seafloor.

Researchers at the Ocean Exploration Trust are pushing the frontiers of this wilderness, which lies more than 3,000 meters below the waves, and the best part is, anyone can watch the exploration.

A highlight reel of the expedition's footage published on YouTube in April 2022 captured the moment researchers operating the deep-sea vehicle stumbled upon the road to Oz.

"It's the road to Atlantis," a researcher on the radio can be heard exclaiming.

"The yellow brick road?" another voice counters.

"This is bizarre," adds another member of the team.

"Are you kidding me? This is crazy."

Despite being located under about a thousand meters of ocean, the lake bed discovered by researchers on the summit of the Nootka seamount looks surprisingly dry.

On the radio, the team notes that the ground looks almost like "baked crust" that could be peeled off.

In one tiny section, the volcanic rock has fractured in a way that looks strikingly similar to bricks.

"The unique 90-degree fractures are likely related to heating and cooling stress from multiple eruptions at this baked margin," reads a caption to the YouTube video.

At first glance, the effect is easily mistaken for a path to a wonderful new world. And in a way, that's not altogether wrong.

Following the brick road is a sign we're headed in the right direction and could soon learn a whole lot more about Earth's hidden geology.

You can read more about the 2022 E/V Nautilus expedition here.

An earlier version of this article was published in May 2022.

Though known only from a shinbone fragment, a newly-described flesh-eating terror just might be the largest known member of its feathered kind.

Phorusrhacid 'terror birds' stalked what's now Colombia's Tatacoa Desert around 12 million years ago, among car-sized armadillo relatives, giant sloths, and saber-toothed marsupial cousins.

The recently analyzed fossil suggests this specimen was far larger than its relatives, which have been estimated to range from 1 to 3 meters (3 and 9 feet) in height.

It also bears signs of how this fearsome predator likely met its end – in the jaws of an even more terrifying beast.

Evolutionary biologist Federico Degrange from Argentina's Center for Research in Earth Sciences and colleagues found the bird's shinbone was marred with teeth marks of an ancient crocodile relative, Purussaurus, thought to grow up to 9 meters (30 feet) long.

"We suspect that the terror bird would have died as a result of its injuries given the size of crocodilians 12 million years ago," says Johns Hopkins University paleontologist Siobhán Cooke.

Past finds reveal Phorusrhacids had massive beaks, making them look awkwardly top-heavy. Those, along with the anatomy of their skull suggests the birds were efficient predators.

"Terror birds lived on the ground, had limbs adapted for running, and mostly ate other animals," Cooke describes.

Luckily for us, Phorusrhacids were extinct well before humans arrived on the scene.

The bone fragment suggests the animal was up to 30 percent larger than previously known specimens of Phorusrhacids. The team suspects it may be a new species, but its limited remains mean they can't rule out the possibility that it belongs to previously discovered terror birds like Titanis.

Found laying on the ground by a fossil collector in the Tatacoa Desert, the remains represent the northernmost Phorusrhacid found in South America to date. Back in the Middle Miocene, before South and North America were connected, the area was lush and tropical.

Such conditions typically encourage decay, reducing the chance of fossilization. The scarcity of Phorusrhacid fossils in this region may also suggest these species were apex predators, the researchers explain, which tend to live in much lower densities than their prey.

"The fact that the vast majority of phorusrhacids have been found in southern South America, and that they appear more recently in the Pliocene sediments of southern North America, suggested that terror birds have a South American origin," Degrange and team write in their paper.

The fossil, first discovered nearly 20 years ago by a curator at the Museo La Tormenta, Cesar Augusto Perdomo, was analyzed using 3D scanning, highlighting the deep pits unique to Phorusrhacid legs.

Today's closest living relatives to Phorusrhacids are almost an extreme opposite of the giant flightless terrors – they're instead slight, long-legged, dainty birds, like the red-legged seriema (Cariama cristata).

Giant, flightless birds that are the stuff of nightmares have evolved independently multiple times since non-avian dinosaurs met their end, including Australia's 'demon ducks' and Gastornis of North America and Europe.

This research was published in Papers in Palaeontology.