Scientists have synthesized a form of glass that can knit itself back together after being damaged by gamma radiation.

Researchers observed films of chalcogenide glass with gamma-ray-induced defects gradually become whole again over time at room temperature, returning to a state of structural integrity without any other intervention.

The discovery, led by engineer Myungkoo Kang of Alfred University in the US, reveals a material that could be really useful in places like space environments, where gamma radiation is streaming constantly, or radioactive facilities where sensors durable to radiation would make a huge difference.

"People are increasingly looking at glasses that have similar optical transparency to crystals such as germanium that can be engineered for their composition and properties for use in applications where germanium may be used," says physicist Kathleen Richardson of the University of Central Florida.

"These glasses are seeing more and more use in systems where the community is looking for alternatives to some of the crystalline solutions that have historically been used before."

Glass is a pretty strange material at the best of times, but extremely useful in various ways. Chalcogenide glasses – those that include sulfur, selenium, tellurium, or polonium – interact with light in ways that make them useful for optical devices, especially in the realm of infrared sensing.

Kang and his colleagues were making just such a glass for use in satellite circuitry, using very precisely mixed amounts of sulfur, germanium, and antimony.

"These glasses exclude oxygen, and that's what makes them special for the infrared," Richardson says. "These are made of elements on the far-right side of the periodic table. When they bond together, they make very infrared-transparent materials but with very large atoms and weak bonds."

These glasses need to be tested under the stresses to which they may be exposed in operating conditions, and one of these for space environments is gamma radiation.

We're not exposed to space gamma rays here on Earth's surface, since our atmosphere works as a highly effective shield, but the radioactive decay of certain elemental isotopes can produce gamma radiation.

To expose their samples to the highly energetic form of light, the researchers placed their samples in irradiators powered by cobalt-60, a synthetic form of radioactive cobalt. This exposure created microscopic defects in the glass by distorting the weak bonds between the atoms.

Then, the glass was placed in room-temperature conditions. By 30 days later, the glass had recovered.

"Because they're big atoms and weak bonds, over time, these bonds can relax back and reform from this distorted arrangement, and therefore heal," Richardson says.

"So, the concept of self-healing glass is that when our experiments get exposed to high-energy radiation, these bonds are distorted or broken. Over time, room temperature is enough to heal these bonds so that the structures can reform themselves."

The potential here is pretty interesting. The glass, or a future form of it, could one day be used as a durable, reversible radiation sensor for extreme environments, for example.

The team hopes to develop the glass further, and use it as a springboard for hopefully creating other glasses that have the same self-healing ability.

"Moving forward, my new research group aims to develop irradiation-induced novel ceramics along with in-situ microstructural and optical metrology methods as a route toward the realization of ultra-fast lightweight optical platforms," Kang says.

"My research under the unifying theme of irradiation effects in chalcogenide ceramics has yielded such an impactful takeaway."

The research has been published in the Materials Research Society Bulletin.

While scratching surfaces is a normal cat behavior, a new study explains why some of our beloved clawed floofs are more destructive than others. And no, they're not just trolling you with their rapscallion ways.

"We show that certain factors – such as the presence of children at home, personality traits of cats, and their activity levels – significantly impact the extent of scratching behavior," says veterinary researcher Yasemin Salgirli Demi̇rbas from Ankara University in Türkiye.

It is important to provide cats with surfaces for them to scratch on, as this activity keeps their claws sharp and prevents them from overgrowing and causing health problems. Scratched surfaces also act as a territorial marker, allowing cats to communicate with their fellow felines.

This, however, is where problems can arise. The more frustrated an owner gets at the cat tearing up the expensive leather couch, the more the cat is likely to scratch in response to heightened social tension, according to Salgirli Demi̇rbas and her colleagues from Portugal, Canada, and France.

The researchers surveyed over 1,200 cat owners – all of whom owned just one cat – to discover stress is the leading cause of excessive scratching in domestic cats. While self-reported data is prone to biases, they found a strong association.

"We see a clear link between certain environmental and behavioral factors and increased scratching behavior in cats," says Salgirli Demirbas.

"Specifically, the presence of children in the home as well as high levels of play and nocturnal activity significantly contribute to increased scratching. Cats described as aggressive or disruptive also exhibited higher levels of scratching."

This tells us how we can work with our cats to alter their behavior.

"Providing safe hiding places, elevated observation spots, and ample play opportunities can help alleviate stress and engage the cat in more constructive activities," advises Salgirli Demirba.

So if your cat is scratching where it should not, it is important to use positive reinforcement strategies, and avoid tactics that could exacerbate the cat's stress. Positive tactics include providing an alternative surface for scratching, close to the cat's chosen scratching area.

Cats usually scratch in socially significant areas, likely as a way to express their emotional state. So the location of their scratching post does matter to them.

It is also crucial to play with your feline companion in a way that works for them. Cats who played for extended periods were more likely to scratch more often, possibly from the stress of being overstimulated, the researchers suspect.

"Promoting regular and brief interactive play sessions, coupled with offering suitable toys, can alleviate stress and consequently reduce undesirable scratching behavior," the team recommends in their paper.

Cats really are particular creatures. They have strong preferences about many things, including how we pat them. Trying to pinpoint a specific stressor behind your cat's scratching response could help you work out how to mitigate the problematic behavior.

"Understanding the underlying emotional motivations of scratching behavior, such as frustration, which seem to be linked to personality traits and environmental factors, allows caregivers to address these issues directly," says Salgirli Demirbas.

Calming cat pheromones can help diffuse the situation in the meantime, while other tactics are investigated.

"Our findings can help caregivers manage and redirect scratching to appropriate materials, which could help foster a more harmonious living environment for both cats and their caregivers," Salgirli Demi̇rbas concludes.

Cats have been our companions for over 10,000 years now, protecting our crops, entertaining us, and providing affection. Trying to understand them better is the least we can do in return.

This research was published in Frontiers in Veterinary Science.

A crucial feature of superconductivity has just been observed at much higher temperatures than scientists had thought possible.

Physicists have found electrons pairing up in the way they do in superconducting materials in an unexpected material, above the incredibly cold temperatures similar materials permit superconductivity to occur.

Superconductivity decribes the way electrons move through a material without any resistance and subsequent energy loss. We've observed this phenomenon in many different materials, but there's a catch. We only seem to be able to make it happen at extremely low temperatures, close to absolute zero (-273.15 degrees Celsius, or -460 degrees Fahrenheit), or slightly less cold temperatures with a lot of pressure.

Although the electrons in the newly tested materials didn't achieve resistance-free flow, their pairing is a critical step required for it to occur, potentially leading to superconductivity that won't need big equipment.

"The electron pairs are telling us that they are ready to be superconducting, but something is stopping them," says physicist Ke-Jun Xu of Stanford University. "If we can find a new method to synchronize the pairs, we could apply that to possibly building higher temperature superconductors."

The material is a layered, copper-based crystal, or cuprate, called neodymium cerium copper oxide (Nd_2−xCe_xCuO₄). At low temperatures, the crystal exhibits superconductivity, yet it becomes significantly more resistant at higher temperatures.

Now, in order for superconductivity to kick in, electrons need their quantum identity to be entangled, turning them into as what's known as a Cooper pair. Only then can they weave smoothly through the atomic forest with zero effort.

Conventional superconductors, which exhibit superconductivity below around 25 Kelvin (-248 degrees Celsius, or -415 degrees Fahrenheit), entangle their electrons through vibrations in the underlying material.

Cuprates are unconventional superconductors, exhibiting superconductivity at temperatures up to 130 Kelvin. Scientists think that there is another mechanism responsible for electron pairing in these materials, yet the exact process is still somewhat murky.

The neodymium cerium copper oxide Xu and his team studied is like a conventional superconductor in that it doesn't exhibit the phenomenon above 25 Kelvin, which allows them to study the stages of superconductivity. As the electrons entangle, they are less resistant to being ejected from the material as the temperature rises; that is, the material loses energy at a lower rate. This is known as the pairing gap.

The team observed their material retaining more energy at temperatures up to 140 Kelvin (-133 degrees Celsius, or -207 degrees Fahrenheit) – far higher than the 25 Kelvin superconductivity transition temperature. This suggests that the electrons form Cooper pairs at pretty high temperatures, relatively speaking.

It's still not clear what is inducing the pairing. And the specific material might not be the one to bring us to room temperature superconductivity. But it could be a means of finding both answers, and the material, in the future.

Superconductivity at ambient temperatures is kind of a big deal. Imagine 100 percent energy efficiency – we could reduce the size of the circuitry required to transport electrons, packing more power into a smaller space for faster, cheaper technology.

But cracking the code has been very hard. We've had a few claimed breakthroughs, such as the much-hyped LK-99, but all of them have amounted to nothing.

Progress is likely to be more incremental – such as observing some of the features of superconductivity in higher-temperature materials, working out why it happens, advancing step by painstaking step.

"Our findings open a potentially rich new path forward," says physicist Zhi-Xun Shen of Stanford University.

"We plan to study this pairing gap in the future to help engineer superconductors using new methods. On the one hand, we plan to use similar experimental approaches at SSRL to gain further insight into this incoherent pairing state. On the other hand, we want to find ways to manipulate these materials to perhaps coerce these incoherent pairs into synchronization."

The research has been published in Science.

A space rock that smacked into Earth 66 million years ago and devastated the ancient life living thereon took a remarkably circuitous route to get here, a new study has found.

The Chicxulub event – the giant impact that ended the reign of non-avian dinosaurs, clearing the way for mammalian life to rise – was triggered by an asteroid from a region of the Solar System out past the orbit of Jupiter, the cold, dark outer limits, far from the Sun's light and warmth.

And an asteroid it was indeed, with the new findings by an international team of researchers ruling out that the object could have been a comet.

This discovery gives us a new understanding of Earth's history, and its interactions with the rest of the Solar System.

Since its infancy, Earth has been repeatedly slammed by large space rocks. It's thought that cometary impacts played a significant role in delivering water to Earth, and we can trace – albeit with varying degrees of difficulty – a number of huge craters scarring the planet after a collision with something large.

Earth has also experienced several mass extinctions, but the only one definitively linked to an impact was the Cretaceous-Paleogene extinction 66 million years ago, responsible for wiping out an estimated 76 percent of all animal species on Earth, including the dinosaurs that didn't go on to have bird descendants.

At the time, an asteroid some 10 kilometers (6 miles) across slammed into what is now the Yucatán Peninsula, leaving behind a colossal crater, and triggering a tsunami of extinctions that changed the world.

Whence originated this deadly rock? We can't exactly rewind time, observe its trajectory through the sky, and trace the arc back to a point in the Solar System. What we can do, however, is look at the layer of sediment preserved in the rock that would have been laid down at the time of the impact, looking for signatures in the minerals that can be matched to known types of space rocks.

In Cretaceous-Paleogene layers, a larger proportion of minerals such as iridium, ruthenium, osmium, rhodium, platinum, and palladium can be found. These platinum-group elements are pretty rare on Earth, especially on the surface. But they're common in meteorites – chunks of rock that fall through Earth's skies from space and slam into the surface.

On the other hand, the Chicxulub impact wasn't the only thing the Earth had going on back then. For nearly a million years around the Cretaceous-Paleogene boundary, a huge volcanic region known as the Deccan Traps was acting out, spewing volcanic material from Earth's underbelly out into the open. This is another possible source of those platinum-group elements observed in the boundary layers.

Led by geochemist Mario Fischer-Gödde of the University of Cologne in Germany, the team wanted to find out, once and for all, whether these minerals were indeed extraterrestrial in origin; and, if so, if they could be traced to a specific type of space rock.

Their studies focused on a mineral called ruthenium, several isotopes of which can be found in the boundary layer. Isotopes are forms of the same element with varying numbers of neutrons, and their ratios to each other in a given sample act as a fingerprint. In terrestrial ruthenium, the isotopes will be found in different proportions from the isotopes in meteorites.

They analyzed the ruthenium from the boundary layer from five different locations: one in Spain, one in Italy, and three from the chalk Cliffs of Stevns in Denmark. They also analyzed ruthenium from five other impacts from the last 541 million years, as well as spherule layers (tiny blobs of meteor sprayed out as the rock melts under the heat of atmospheric entry) dating back to 3.5 to 3.2 billion years ago.

In addition, the researchers analyzed ruthenium from actual meteorites, and checked these results against terrestrial reference samples of ruthenium that formed right here on Earth. This comparison revealed that the ruthenium in the Cretaceous-Paleogene boundary layer was not home-made – it came from space.

And not any old where in space. It was most consistent with a rare type of asteroid called a carbonaceous chondrite, rich in carbon, hailing from the outer Solar System, past the orbit of Jupiter.

The five other impacts were siliceous asteroids, which are found closer to the Sun, and are more common here on Earth. And the ancient spherule layers were, again, carbonaceous, hurled at Earth during the final stages of its mass accumulation.

These results finally reveal the identity of the rock that caused so much havoc. Jupiter is thought to act as something of a barrier to outer Solar System objects, catching asteroids in its orbital path and preventing them from traveling farther in towards the Sun. Some do manage to slip through from time to time, but they normally fall to Earth in smaller chunks than the Chicxulub impactor.

Which raises the question: why was that ancient rock on such a dedicated vendetta against the dinosaurs? Science may never know.

The research has been published in Science.

Extreme weather events and rising seas are putting precious heritage sites around the world in harm's way.

A precious stone pyramid in Mexico is the latest to succumb to an increasingly chaotic global climate. On the night of July 29, the 15-meter-high (roughly 50-foot-high) square monument located in the state of Michoacán suddenly slumped under the pressure of incessant rain, its south wall crumbling into a pile of rubble.

The pyramid was once one of the best-preserved monuments of the Michoacán Kingdom civilization. It is located at Ihuatzio, a remarkably preserved archaeological site that contains one other pyramid, a tower or fortress, and some tombs.

It was first occupied 1,100 years ago by indigenous Nahuatl-speaking groups. Later, it became the headquarters of the P'urhépechas people, the only empire the Aztecs couldn't conquer. The culture still thrives to this day.

Only one of the pyramids at the site has been damaged, but personnel from Mexico's National Institute of Anthropology and History (INAH) say that at least six of its 'stepped bodies' are in disrepair, including the outer wall, and the core and retaining wall.

They blame the extreme weather events of recent weeks.

In July, the peak of the Northern Hemisphere summer, heavy rainfall and thunderstorms battered much of Mexico. This came after the worst drought in the nation in 30 years, when rain became so scarce, several lakes dried up completely.

"The high temperatures, previously recorded in the area, and the consequent drought caused cracks that favored the filtration of water into the interior of the pre-Hispanic building," said an INAH statement.

From there, collapse became all but inevitable. Officials are now focused on repairing the structure of the building "in favor of the cultural heritage of Mexicans."

It's the job of archaeologists to study human behavior in times gone by, but inevitably, their work is also impacted by current human activities.

Extreme weather and rising seas, driven by human-caused climate change, are proving to be a serious nuisance for important sites of bygone cultures.

Recently, archaeologists found that ancient cave paintings in oceania are deteriorating with accelerating climate changes.

And just this year, a study on cultural heritage building materials in Europe and Mexico found when precipitation increases substantially, it puts these buildings at risk of damage.

According to Tariakuiri Alvarez, who identifies as a living member of the P'urhépecha tribe, his ancestors would have interpreted the crumbling of the pyramid at Ihuatzio as a "bad omen."

In a recent Facebook post Alvarez said that before the arrival of foreign conquerors in Mexico, something similar happened, and it was because the gods were "displeased".

Just days before the pyramid in Mexico tumbled down, Utah's iconic 'Double Arch' also caved in, probably due to changing water levels and erosion.

Heritage sites like these are priceless places that humans wish to preserve for future generations. Watching them collapse from a climate that has been drastically altered by our own behavior is disgusting to watch, and not just for immortals.

We all had to make adjustments as the COVID-19 pandemic unfolded – even zoo animals who were suddenly not seeing crowds of visitors pass by every single day.

In a study published in 2022, researchers discovered how primates reacted to that shift, looking at the behavior of bonobos, chimpanzees, western lowland gorillas, and olive baboons, and finding that the animals changed their habits in a variety of ways, including the amount of time they spent resting and eating.

Visitor interactions are thought to be crucial to the welfare of zoo animals. Yet these interactions have the potential to be either positive or negative. So the researchers were keen to see the difference when the crowds weren't there.

"Primates are some of the most cognitively advanced species in zoos and their interactions with visitors are complex," zoo animal welfare scientist Samantha Ward from Nottingham Trent University in the UK explained at the time.

"A limitation to understanding how visitors can affect behavior of animals in zoos and parks is that they rarely close to the public for prolonged periods, so this provided us with a unique opportunity."

Observations were recorded at Twycross Zoo and Knowsley Safari in the UK, both before and after visitors returned.

Over several months and multiple open and closure periods, there were noticeable changes in primate behavior, which varied depending on the animal.

As visitors began to return to the zoo, the bonobos and gorillas spent less time alone, while the gorillas also spent less time resting. Chimpanzees, meanwhile, were eating more and engaging with their enclosures more when zoos reopened.

The olive baboons in the safari park were seen to engage in less sexual and dominance behavior when the visitors came back. They also tended to approach visitor cars more often, compared with the ranger vehicles they saw when the park was closed.

Whether or not these changes were positive is more difficult to say.

The researchers suggest that the returning visitors seemed to stimulate the chimpanzees and baboons, while gorillas and bonobos spending less time alone could also be viewed as positive.

At the same time, it could be argued that gorillas – naturally more sedentary animals – were disrupted by the crowds in that they spent less time resting.

That the gorillas changed the parts of their enclosures they spent the most time in when visitors came back suggests that the animals can to some extent manage this disruption.

"Behavioral changes and changes in enclosure use in the presence of visitors highlights the adaptability of zoo species to their environments," said zoo animal welfare researcher Ellen Williams from Harper Adams University in the UK.

"Provision of environments which enable animals to actively adapt in this manner is really important for their welfare."

The team also observed that there was a visitor number threshold when it came to olive baboons, beyond which the animals stopped becoming increasingly active and stimulated by the passing cars in the safari park.

This is all valuable data for animal welfare researchers, who know that visitors can have all kinds of effects on wildlife – from adding feelings of companionship and safety, to being sources of annoyance or even threats. This needs to be factored into how zoos and parks are run and designed.

While there might not be any more lockdowns in the foreseeable future (hopefully), the research team wants to continue the work of studying how visitor numbers affect animal behavior, including collecting data involving more animals and across a longer time scale.

"Future work could involve looking at the impact on a wider range of species in both zoos and safari parks as well as differences among individual animals," said Williams.

The research was published in Animals.

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

Last year, health experts predicted the 'mic drop' joke in the final scene of the blockbuster Barbie movie would have a serious real-world impact, prompting viewers to seek reproductive healthcare they might've needed, put off, or perhaps never thought about.

Now it seems they were right, with a new study finding a spike in related web searches following the film's release.

For those who haven't seen the movie, Eva Sénéchal, a psychology researcher at McGill University in Montreal, and her colleagues, who conducted the new analysis of internet search trends, explain how the final line in the Barbie film may have done more than just make audiences laugh.

"In the film's final scene, after deciding to leave Barbieland for the real world, Barbie enthusiastically tells a receptionist, "I'm here to see my gynecologist," a joke that could be based either on her supposed lack of genitals or her evident excitement for care many women find unpleasant." Sénéchal and colleagues write in their paper.

"We hypothesized that this final line may have spurred public interest in gynecologic care."

The researchers charted weekly internet searches in the US following Barbie's release, looking for 34 terms ranging from questions about what gynecologists do to more general searches of "gynecologist near me", "make a doctor's appointment", and "pap smear".

There was a positive spike in searches relating specifically to gynecologists, with questions such as "Why see a gynecologist?" and "Do I need a gynecologist?" more than doubling in the three months following the film's release in July 2023 compared to the year prior.

However, looking up information about gynecologists is only the first step in seeking that kind of specialist healthcare. The study didn't look at other data that may have captured whether movie-watchers were prompted to make or attend appointments, but trends in other search terms suggest not.

"There were no changes in searches for gynecologist appointments, suggesting that searches for information about gynecologists did not translate to searches for new gynecologic care," Sénéchal and colleagues write.

"Therefore, it remains unclear whether a 'Barbie effect' in awareness would translate to improved measurable health outcomes."

But it's not out of the question; it has happened before.

In 2013, when actress Angelina Jolie went public with her decision to undergo a double mastectomy after testing positive for an inherited breast cancer gene, referrals for genetic counseling and testing in the UK more than doubled – a trend dubbed the 'Angelina Jolie effect'.

The Barbie film could have also had a wider impact on body image, just like the dolls themselves. Research shows that Barbie dolls, which traditionally have represented extreme and unrealistic body shapes, can influence young girls' ideas about body image and eating habits, although the results are a mixed bag.

"We know that children learn by observing, absorbing, and imitating the things they see around them, and that their early ideas about weight and appearance are shaped by their family, their peers, and the media," Zali Yager, a body image researcher, wrote for Women's Health Agenda after seeing the film in July 2023.

But it's difficult to tease apart the influence of those three factors – one's family, friends and (social) media – on a person's perception of themselves, or their healthcare-seeking behaviors, in the case of this new analysis.

"There's so much of the context that we are missing in these studies," clinical health psychologist Jennifer Webb, of the University of North Carolina at Charlotte, told Nature in a July 2023 interview, referring to the mixed results of research studies on Barbie's influence on body image and self-esteem among young girls.

"We don't know about the other aspects of the children's social environment, whether in the immediate home environment, at school or other activities."

The same is true of Sénéchal and colleagues' new analysis: Trends in internet searches give us only a snapshot of people's lives, and tell us nothing about who those anonymous people are, their age or their health.

Although we don't have the data to show it, some people might have been inspired to seek out reproductive healthcare for themselves because watching Barbie attend her first gynecologist appointment "normalizes the experience," physician and health policy researcher Leana Wen told CNN last year.

"It solidifies the understanding that reproductive health is an integral part of overall health."

The research has been published in JAMA Network Open.

There, in the ancient, long-abandoned Maya city of Cobá, near the towering Nohoch Mul pyramid, a vast stone slab was found tucked away in what was once the floor of a sacred pool. What makes this slab so special is what it bears: an inscription consisting of 123 glyphs, painstakingly carved into its surface.

Initial inspection suggests that the glyphs describe the founding date of a town called Keh Witz Nal, or "Deer Mountain", on 12 May 569 CE. They also name a previously unknown Maya ruler – K'awiil Ch'ak Chéen, a name invoking K'awiil, the Maya god of lightning.

Other glyphs refer to the gods who were thought to have founded Cobá, including Bolón Tz'akab Ajaw – the lord of countless generations.

Located in what is now the state of Quintana Roo on the eastern side of the Yucatán Peninsula, the once-glorious, now ruined city of Cobá may have been built by the Maya as early as 50 BCE and continuously inhabited for over 1,500 years, with the most recent buildings constructed between 1200 and 1500 CE. At its peak, it was a thriving cultural hub boasting an estimated 50,000 inhabitants.

It's one of the few archaeological sites to still carry its Maya name, Ko'ba a, a name that means rough waters, and it's filled with engravings and sculptures that reveal much about the spiritual and aesthetic lives of the Maya who once lived there.

Excavations at the site are very careful and painstaking, and Mexico's National Institute of Anthropology and History (INAH) has been taking its time to uncover and restore the monuments of the city that have become temporarily lost to the jungle and time.

The stone slab was discovered at the bottom of what was once a pool, and it's stunning. It covers an area of 11 square meters (118 square feet), with glyphs painstakingly carved onto its surface in a sort of L-shaped arrangement that accommodated the shape of the stone.

Previously, 14 rulers of Cobá had been identified, including three women, one of whom reigned for 40 years. With the new information contained in the heavily stylized script, the researchers were able to corroborate that many of these rulers adopted the name of the god K'awiil.

A more in-depth study of the inscription will be made, but for now, the archaeological team is focused on restoring and preserving the stone against further damage from water and erosion.

A detailed, high-resolution 3D construction has been made, and will enable further study without disturbing the stone further.

The progress of a human being through life might be thought of as a mostly gradual succession of changes from the ovum to the grave.

But if you wake up one morning, look in the mirror, and wonder when you suddenly grew so much older, you may not be imagining things.

According to new research into the molecular changes associated with aging, humans experience two drastic lurches forward, one at the average age of 44 and the other at the average age of 60.

"We're not just changing gradually over time; there are some really dramatic changes," says geneticist Michael Snyder of Stanford University, senior author of the study.

"It turns out the mid-40s is a time of dramatic change, as is the early 60s. And that's true no matter what class of molecules you look at."

Aging is complex, and associated with growing risks of diseases of all kinds. Snyder and his colleagues have been investigating the biology of aging to better understand what changes occur and how, in order to better mitigate and treat these ailments. To this end, they have been tracking a group of 108 adults, who have been donating biological samples every few months over several years.

They noticed that in some conditions, such as Alzheimer's and cardiovascular disease, risk doesn't rise gradually with time, it escalates sharply after a certain age. So they wanted to take a closer look at the biomarkers of aging to see if they could identify related changes.

Using the samples from their cohort, the researchers have been tracking different kinds of biomolecules. The different molecules studied include RNA, proteins, lipids, and gut, skin, nasal, and oral microbiome taxa, for a total of 135,239 biological features.

Each participant submitted an average of 47 samples over 626 days, with the longest-serving participant submitting 367 samples. This wealth of data resulted in more than 246 billion data points, which the researchers then processed, looking for patterns in the changes.

Several previous studies have found non-linear changes in molecular abundances that can be linked to aging in rats and humans. Studies of fruit flies, mice, and zebrafish have also pointed to a stepwise aging process in those species.

Snyder and his colleagues noticed that there's a very clear change in the abundances of many different kinds of molecules in the human body at two distinct stages.

Around 81 percent of all the molecules they studied showed changes during one or both of these stages. Changes peaked in the mid-40s, and again in the early 60s, with slightly different profiles.

The mid-40s peak showed changes in molecules related to the metabolism of lipids, caffeine, and alcohol, as well as cardiovascular disease, and dysfunctions in skin and muscle. The early 60s peak was associated with carbohydrate and caffeine metabolism, cardiovascular disease, skin and muscle, immune regulation, and kidney function.

The first peak, the mid-40s, is typically when women start undergoing menopause or perimenopause, but the researchers ruled this out as a main factor: men, too, also underwent significant molecular changes at the same age.

"This suggests that while menopause or perimenopause may contribute to the changes observed in women in their mid-40s, there are likely other, more significant factors influencing these changes in both men and women," explains metabolomicist and first author Xiaotao Shen, formerly of Stanford, now at Nanyang Technological University Singapore.

"Identifying and studying these factors should be a priority for future research."

The researchers note that their sample size is pretty small, and they tested limited biological samples, from people between the ages of 25 and 70.

Future research could help delve further into this phenomenon, studying it in more granular detail, across a wider range of subjects, to better understand how the human body changes over time.

The research has been published in Nature Aging.

People who are pregnant or breastfeeding should be warned that using cannabis in any way, shape, or form has the potential to negatively impact their developing child.

A new, preclinical study on rats spotlights the possible dangers of managing morning sickness or other symptoms of pregnancy with products containing either THC (Δ9-tetrahydrocannabinol) or CBD (cannabidiol).

Researchers at the University of Western Ontario and Queen's University in Canada found rats that are regularly exposed to THC and CBD while still in the womb show significant changes to their development, even when the chemicals are administered without any additional compounds commonly found in cannabis.

THC is the more psychoactive of cannabis's mix of plant molecules. Concerningly, the cannabinoid can cross the placenta into fetal circulation in similar concentrations to what is seen in the blood of the mother. As early as 14 weeks, the human fetus possesses neural receptors for cannabinoids.

CBD is another major compound in cannabis. It is widely accessible and considered harmless by many, yet few studies have investigated whether it is safe for use during pregnancy.

While CBD doesn't deliver an intoxicating 'high', the compound has its own effects on the body. And, like THC, it can also readily cross the placenta in rodent studies, where it seems to impair the shape and function of the organ.

In the current study, researchers investigated both compounds. For nearly an entire pregnancy, rat mothers were given daily doses of THC, CBD, or a combination of both compounds.

The pups that were exposed to a low dose of THC had a reduced birth weight compared with control mice, as did pups exposed to CBD while in the womb. Rat offspring exposed to THC and CBD together were born with even lower body and brain weights.

While growth rates had recovered by adolescence, some of the pups went on to show behavioral changes and disrupted neuronal activity in certain brain regions.

The findings support human health studies that have linked cannabis exposure in pregnancy to low birth weight, cognitive and behavioral changes, and a higher risk of neuropsychiatric disorders.

"Marjiuana has been legalized in Canada and in many states in the US, however, its use during pregnancy has not been well studied up until this point," says David Natale from Queens.

"This study is important to support clinicians in communicating the very real risks associated with cannabis use during pregnancy."

In the US, 24 states have legalized cannabis for recreational use, and some surveys suggest the drug has doubled in popularity among those who are pregnant, who often use it to treat mood, morning sickness, pain, or sleep issues.

The US Surgeon General, the American College of Obstetricians and Gynecologists, and the American Academy of Pediatrics all agree that in the absence of further evidence, cannabis use of any kind during pregnancy is inadvisable.

Nevertheless, many women remain unaware of the possible risks.

An experiment on rats isn't enough to prove once and for all that cannabis use during pregnancy is dangerous, but it does provide insight into some of the concerning associations researchers are finding in epidemiological studies.

In the current research, male rat offspring that were exposed to THC in the womb were the only ones to exhibit impaired cognitive behavior in adolescence.

Female offspring exposed to THC in the womb showed typical neurological outcomes and almost a "complete lack of molecular changes", researchers say.

When mice were exposed to CBD on its own, however, it had a surprising impact on later brain development. In adolescence, both male and female mice exposed to CBD showed signs of neuropsychiatric issues.

Female offspring exposed to prenatal CBD alone and CBD and THC together displayed anxiety-like behavior in tests. Whereas male offspring exposed to THC and CBD, showed impulsivity-like behaviors.

"In contrast to the popular belief that CBD is safe for use in pregnancy, CBD alone produced distinct long-term neuropsychiatric effects and did not mitigate the consequences of prenatal THC," write the authors of the study.

Given how popular CBD and THC products have recently become, these findings emphasize the need for more rigorous research on cannabis use during pregnancy, and its possible impacts on a developing fetus.

The study was published in Neurobiology of Disease.

The longest genome of all the animals on Earth belongs not to a giant, or a cognitively advanced critter, but a writhing, water-dwelling creature seemingly frozen in time, right at the cusp of evolving into a beast that can live on land.

These are the lungfish, a class of freshwater vertebrates whose peculiar characteristics are reflected in a colossal genetic code. Able to breathe both air and water, with limb-like fins, and a well-developed skeletal architecture, these strange ancient creatures are thought to is thought to share a common ancestor with all four-limbed vertebrates known as tetrapods.

Knowing what this length genome actually contains might be able to give us information about how our ancestors emerged from the soggy depths to walk on land, and scientists have just made a breakthrough. They've sequenced the biggest of the lungfish genomes, that of the South American lungfish, Lepidosiren paradoxa.

"With over 90 gigabases (in other words, 90 billion bases), the DNA of the South American species is the largest of all animal genomes and more than twice as large as the genome of the previous record holder, the Australian lungfish," says evolutionary biologist Axel Meyer of the University of Konstanz in Germany.

"Eighteen of the 19 chromosomes of the South American lungfish are each individually larger than the entire human genome with its almost 3 billion bases."

That marathon of DNA bases equals some 30 times the length of the human genome, to put it into perspective. Curiously, the team only counted around 20,000 protein-coding sequences.

The African lungfish (Protopterus annectens), which the researchers also sequenced, featured a similar number of individual genes, putting both coding counts roughly in the same ballpark as our own genetic library. That leaves a lot of extraneous DNA for researchers to ascribe a purpose.

Sequencing the two lungfish species follows similar work on the Australian lungfish (Neoceratodus forsteri), published three years ago. The combined sequences reveal new insights into how these fish diversified and evolved over the last 100 million years.

Lungfish are so named because, unlike other species of fish, they actually have a lung or two for respiration, a trait that would be key for enabling the transition to tetrapod life.

Those three lineages – African, South American, and Australian – are all that remain to this day. They are considered living fossils, and comparing the different ways they have all changed since the first tetrapods emerged some 390 million years ago (give or take, it's up for debate) can help us understand a vital turning point in the evolution of life on Earth, including our own species.

Meyer, his co-lead biochemist Manfred Schartl of the University of Würzburg in Germany, and their international team found that the reason Lepidosiren's genome is so huge has to do with a high number of 'jumping genes', AKA transposable elements.

These rogue sequences can copy themselves and move around the genome, which can be to the detriment of the organism they are found in – but they can also trigger rapid genetic changes.

Research on another living fossil somewhat closely related to lungfish, the coelacanth, revealed that transposons could have played a pretty significant role in the evolution of the tetrapods. Lepidosiren might be a clue as to why. For the past 100 million years, every 10 million years, the genome has grown by the entire size of the human genome.

This, the researchers found, is likely because piRNA, a type of RNA that normally suppresses transposon activity, is very low in lungfish. So their genome just ballooned.

"And it continues to grow," Meyer says. "We have found evidence that the transposons responsible are still active."

Because the jumping genes are still partying away in Lepidosiren, the researchers assumed the genome would be too difficult to analyze. To their surprise, they found that the genome is remarkably stable, and the arrangement of genes pretty conservative, keeping the lungfish lean and mean.

That also meant, though, that the researchers could reverse engineer the chromosome architecture of ancestral lobe-finned fish, not just for the three species they studied but ancesters to all tetrapods. This ancestry was confirmed by the research, giving us a more complete set of tools for understanding our own evolutionary path.

The researchers were also able to tally up some of the interesting differences between the three individual species. Australian lungfish have just one lung and can still use their gills, and have also retained the limb-like fins that once allowed them to move onto land. African and South American lungfish have atrophied gills and a pair of lungs, and their limbs evolved back into filamentous fins.

By conducting studies with mice edited to carry lungfish genes the team showed that this limb reversion had to do with changes in a signaling pathway called Shh that guides embryonic development. And more discoveries await.

"The genomes of all three lineages of lungfish, because of their crucial phylogenetic position, hold the key to a better understanding of how molecular and developmental processes and genomic evolutionary changes contributed to the conquest of land and the evolution of tetrapods, one of the main transitions during vertebrate evolution," the researchers write in their paper.

"The resource of chromosome-level genomes for all living lungfish lineages will now enable further research into lobe-finned ancestors of tetrapods who conquered land in the Devonian."

The research has been published in Nature.

For the first time ever, more Americans are regularly using cannabis than they are drinking alcohol.

While smoking weed for a recreational high is considered by many to be a safer alternative to using tobacco or even drinking alcohol, there is a lack of evidence on the long-term health impacts of the drug. What little is known suggests it may not be as harmless as some think.

A new investigation from the American Head and Neck Society finds that excessive cannabis use disorder may increase the risk of developing any head or neck cancer, including oral, oropharyngeal, nasopharyngeal, salivary gland, and laryngeal cancer.

The study's authors, led by epidemiologist Tyler Gallagher from the University of Southern California, Los Angeles, say their results should be "interpreted cautiously", as there is a chance they did not fully control for alcohol and tobacco use, as well as HPV status – all of which can contribute to the risk of developing head or neck cancers.

What's more, the study did not measure the amount or the potency of the cannabis participants consumed, how often it was consumed, or how the cannabis was consumed (whether it be vaped, smoked, or ingested).

Nevertheless, head and neck surgeon Niels Kokot from the University of Southern California says, "This is one of the first studies – and the largest that we know of to date – to associate head and neck cancer with cannabis use. The detection of this risk factor is important because head and neck cancer may be preventable once people know which behaviors increase their risk."

The research relied on 20 years of clinical records belonging to 116,076 individuals diagnosed with a cannabis-related disorder that was "substantial enough to cause physical or emotional symptoms with the inability to cease cannabis use."

This group was then compared to a cohort of nearly 4 million individuals who did not have cannabis use disorder.

In the end, the relative risk of developing head and neck cancer was 3.5 to 5 times greater for those with cannabis use disorder than those without.

To put that in perspective, the relative risk of developing a head and neck cancer for people who use tobacco is 2 to 10 times greater than those who don't, while the relative risk for people who consume alcohol is 5.7 for oral and pharyngeal cancers, and 3.2 for laryngeal cancer.

"Given that our cohort included those with the highest use of cannabis, we can estimate that the association of cannabis use seen in this study with risk of developing HNC was slightly less than that of alcohol and tobacco use," conclude Gallagher and his colleagues.

The results are intriguing, but more research is needed to figure out whether this association is causal and what mechanisms might be at play. The current cohort was assumed to be heavy cannabis users because of their diagnosis of cannabis use disorder, but their actual usage was never properly measured.

Previous clinical studies that have investigated the association between cannabis use and head and neck cancer have produced mixed results, and most did not find an association even after following cannabis users for up to eight years.

Earlier this year, the US Drug Enforcement Agency announced its plans to ease federal restrictions on cannabis, reclassifying it from a Schedule I drug to the less restricted Schedule III.

Scientists hope this action removes some of the current barriers to cannabis research, opening up the field like never before.

The study was published in JAMA Otolaryngology – Head & Neck Surgery.

New research suggests the keto diet could put us at risk of heart disease, stroke, type 2 diabetes, and irritable bowel disease, to name a few concerns.

The study was small, but the results might make people think twice about whether a keto diet is worth the trouble.

Led by researchers from the University of Bath (UoB) in the UK, the team had 53 healthy adults follow one of three diets for 4 to 12 weeks: a low-carb ketogenic (keto) diet, a low-sugar diet, or a diet with moderate sugar and carbohydrates.

They found the keto diet increased cholesterol, reduced good gut bacteria, and reduced the body's ability to tolerate sugars, shifting the body's energy source from glucose to fats.

Both the low-sugar diet and the keto diet led to fat loss without affecting people's physical activity levels. It seems people hoping to achieve a leaner body are better off cutting added sugars, not carbs, from their diet.

"The ketogenic diet is effective for fat loss, but it comes with varied metabolic and microbiome effects that may not suit everyone," explains physiologist Dylan Thompson from UoB.

"In contrast, sugar restriction supports government guidelines for reducing free sugar intake, promoting fat loss without apparent negative health impacts."

Those on the keto diet consumed less than 8 percent of their calories from carbohydrates. The low-sugar diet included less than 5 percent of energy intake from free sugars – those added to food and drinks or present in fruit juice, syrups, and honey.

These were compared to a control diet with moderate sugar and carbohydrates, where free sugar contributed around 18 percent of energy intake.

By week four of the keto diet, participants' gut microbe diversity had changed, with massive reductions in the relative abundance of Bifidobacterium, which you may know as one of the heroes of probiotics.

These bacteria rely on dietary fibers that were cut by 40 percent in the keto diet compared to the moderate sugar and carb diet, and the fact that this shift in the gut ecosystem persisted at week 12 of the keto diet is evidence that the diet can cause this internal chaos.

The keto diet's effect on cholesterol was particularly concerning to the researchers, while participants on the low-sugar diet had actually reduced their total cholesterol concentrations by week 12 of the study.

"Despite reducing fat mass, the ketogenic diet increased the levels of unfavorable fats in the blood of our participants," says UoB nutrition scientist Aaron Hengeist.

"If sustained over years, [this] could have long-term health implications such as increased risk of heart disease and stroke."

While the keto diet reduced fasting glucose levels, it also reduced the body's ability to handle carbs from a meal, the researchers explain.

"By measuring proteins in muscle samples taken from participants' legs, we think this is probably an adaptive response to eating less carbohydrates day-to-day and reflects insulin resistance to storing carbs in muscle," says UoB human physiologist Javier Gonzalez.

People on the keto diet had increased levels of the enzyme PDK4 in their skeletal muscle, which is also seen in type 2 diabetes. The diet also reduced levels of the enzyme AMPK and the protein GLUT4, which play important roles in glucose metabolization.

"This insulin resistance is not necessarily a bad thing if people are following a ketogenic diet, but if these changes persist when people switch back to a higher carbohydrate diet it could increase the risk of developing type 2 diabetes in the long term," Gonzalez says.

This research was published in Cell Reports Medicine.

Researchers have discovered that a daily dose of vinegar could improve symptoms of depression, pointing to the possibility that future treatments might come with a few spoonfuls of sour.

A team led by Arizona State University not only tested the effects of regular vinegar consumption but also looked at metabolic activity – the chemical processes that convert food into energy and other biological materials – to look for reasons for the benefits seen with vinegar.

A significant 86 percent boost in the levels of nicotinamide (a form of vitamin B₃) was noticed across the study participants who took liquid vinegar each day. The nutrient has previously been linked to anti-inflammatory effects.

"This data provides additional support that daily vinegar ingestion over four weeks can improve self-reported depression symptomology in generally healthy adults and that alterations in [vitamin B₃] metabolism may factor into this improvement," write Arizona State University dietician Haley Barrong and colleagues in their published paper.

The trial was completed by a total of 28 overweight but otherwise healthy adults, who were split into two groups: one group taking two tablespoons of red wine vinegar twice daily, and the other group taking a daily pill with a very small amount of vinegar in it.

Across the course of the four-week experiment, the participants were asked to answer questions across two standard mental health surveys: the Center for Epidemiological Studies Depression (CES-D) questionnaire, and the Patient Health Questionnaire (PHQ-9).

Although there was no significant difference between the groups on the CES-D, on the PH9-Q, there was an average drop of 42 percent in depressive symptoms for the high vinegar level group compared with 18 percent for the control group taking the vinegar pill.

There are some limitations: it was a small sample size, the patients had low-level depression to begin with, and the improvements in PHQ-9 symptoms were not significant in a secondary analysis that adjusted for baseline survey scores. But Barrong and her team say the findings warrant a closer look at the relationship.

"Depressive disorders are the most prevalent mental health conditions in the world," write the researchers.

"The commonly prescribed antidepressant medications can have serious side effects, and their efficacy varies widely. Thus, simple, effective adjunct therapies are needed."

Studies continue to make progress in better understanding what depression is and all the different factors that can potentially play into it – from sleep quality to body temperature.

What's clear is that depression varies a lot between individuals, and that's where having a wider range of potential treatments can be so useful.

"Future research examining the effects of vinegar administration in clinically depressed or at-risk populations, and those on antidepressant medications, is warranted," write the authors.

"A focus on mechanisms and large patient samples will strengthen the science and provide the evidence to more firmly demonstrate vinegar's role in health promotion."

The research has been published in Nutrients.

The once-majestic, now fallen stone that represents perhaps the strangest component of Stonehenge traveled a very long way to take pride of place in the mysterious ancient megalith.

The so-called Altar Stone, new research has revealed, was transported all the way from Scotland, a journey of more than 750 kilometers (466 miles), to be installed in the monument that sits smack-bang in the south of England.

We don't know how the Neolithic humans that erected Stonehenge managed to carry such a heavy block over hill and dale some 5,000 years ago, but the finding suggests that the ancient marvel may be even more important than we knew.

"These findings are truly remarkable – they overturn what had been thought for the past century," says geologist Richard Bevins of Aberystwyth University in the UK.

"We have succeeded in working out, if you like, the age and chemical fingerprints of perhaps one of the most famous of stones in the world-renowned ancient monument."

Stonehenge, eldritch and ancient in the green British landscape, flecked with lichen, standing (and laying) in a somber, silent array, has mystified and fascinated humans for centuries. We're not certain of who built it, or what it was for. What we can do, however, is look at what we have – and that's the stones themselves.

Many of the stones that make up Stonehenge are igneous bluestone, others sarsen sandstone. The inner ring of bluestones has been traced to a quarry in Wales, some 230 kilometers away. But the Altar Stone at the center is a purplish-green slab of sandstone whose provenance was not as easy to trace.

The Altar Stone, also known as Stone 80, is very odd. It's sunken flush into the ground, with two other stones laying perpendicularly atop. Archaeologists can't tell whether it was installed thus, or once towered, standing as the other stones, before toppling over to be pushed down into the Earth. If it did stand, it would weigh an estimated 6 tonnes (6.6 US tons). It also measures some 4.9 meters (16 feet) long. That's fairly consistent with the rest of the stones.

Its position is neatly aligned with the direction of the Sun at the solstices, implying importance. The stone's value is also suggested by the rock from which it was hewn, so different from the monoliths around it.

A team of researchers had previously conducted a chemical analysis of the sandstone that makes up the Altar Stone to determine if its signature could be traced to nearby locations. They found that the stone's anomalously high barium content could not be linked to any of the sandstone that formed or appeared in the landscape nearby.

So, they extended their search farther afield. Led by geologist Anthony Clarke of Curtin University in Australia, the researchers conducted a thorough analysis of mineral grains within the sandstone; specifically, they focused on grains of zircon, apatite, and rutile from two samples of the stone.

Isotopic dating of these grains allowed the researchers to construct an age profile for the stone. For example, some of the zircons had formed between 4 and 2.5 billion years ago, with younger grains dating to 1.6 to 1 billion years ago. The apatite and rutile, by contrast, formed between 470 and 458 million years ago.

This range of ages described a profile that bore a remarkable similarity to the old red sandstone sedimentary deposits in just one location out of all the sandstone deposits the team checked around the UK and Ireland.

"This provides a distinct chemical fingerprint suggesting the stone came from rocks in the Orcadian Basin, Scotland, at least 750 kilometers away from Stonehenge," Clarke explains.

"Given its Scottish origins, the findings raise fascinating questions, considering the technological constraints of the Neolithic era, as to how such a massive stone was transported over vast distances around 2600 BCE."

We still don't know exactly how the stone was transported, but the terrain across that vast distance would have posed challenge after challenge. This points to a feat of remarkable ingenuity and determination.

It also suggests that the Neolithic people who inhabited the land may have had some means of marine transportation, and sophisticated trade networks may have been at play. Although more study will need to be conducted into the whys and hows, the fact of the Altar Stone's existence, where it exists, can only be gobsmacking, no matter which way you slice it.

"The distance traveled is astonishing for the time," says geochemist Nick Pearce of Aberystwyth University.

"There's no doubt that this Scottish source shows a high level of societal organization in the British Isles during the period. These findings will have huge ramifications for understanding communities in Neolithic times, their levels of connectivity and their transport systems.

"Hopefully, people will now start to look at the Altar Stone in a slightly different context in terms of how and when it got to Stonehenge, and where it came from. I am sure this will lead to some new thinking about the development of Stonehenge and its links to the rest of Neolithic Britain."

The research has been published in Nature.

On an ordinary morning long ago, at the foothills of what are now the Pyrenees of Spain's Iberian Peninsula, a group of Neanderthals woke, greeted the day, and set about their tasks in the growing light.

They could not have known that, tens of thousands of years later, modern humans scurrying about in the dirt would find traces of their existence, and be able to reconstruct details about how they lived their lives. That, however, is exactly what archaeologists have now done – discovering that Neanderthals were far more resilient than we suspected.

The excavation of a recently discovered rock shelter site called Abric Pizarro has turned up thousands of artifacts dated to between 65,000 and 100,000 years ago, including stone tools and animal bones that can tell us a lot about the Neanderthal way of life during a period for which few remnants remain.

And, surprisingly, those bones include the remains of many small animals – revealing that Neanderthals were versatile hunters, able to adapt their lifestyle to food availability.

"Our surprising findings at Abric Pizarro show how adaptable Neanderthals were," says zooarchaeologist Sofia Samper Carro of the Australian National University.

"The animal bones we have recovered indicate that they were successfully exploiting the surrounding fauna, hunting red deer, horses and bison, but also eating freshwater turtles and rabbits, which imply a degree of planning rarely considered for Neanderthals."

Neanderthals (Homo neanderthalensis) constituted one of the closest hominid relatives to modern humans (Homo sapiens), to the point that the two species repeatedly mated, and may not even be a separate species at all. But for some reason, there has been a persistent notion that Neanderthals were primitive, uncultured, and cognitively less developed than today's humans.

In recent years, more and more discoveries have been contradicting this notion. Neanderthals made sophisticated tools, and decorated their environment with different kinds of art.

The main problem with decoding the lives of the Neanderthals is the survivability of the artifacts they left behind. Neanderthals went extinct some 40,000 years ago, and most of the detritus of their lives has succumbed to the ravages of time, decay, and erosion. What we have been able to recover suggests that the Neanderthals were hunters only of large prey, such as horses and rhinoceroses.

Abric Pizarro was a Neanderthal rock shelter discovered in 2008, and archaeologists have been carefully working to dig up its secrets since 2009. Samper Carro and her colleagues have now conducted a thorough survey of some of the artifacts recovered.

The researchers conducted optically stimulated luminescence dating to determine the age of the sediment in which the objects were buried; that's a technique that can determine when a mineral sample was last exposed to sunlight.

They also analyzed pollen grains and bones found at the site, looking at the latter for signs of cut marks and gnawing. And they studied the stone tools, to gauge the knapping techniques and technologies available to the people who once inhabited Abric Pizarro.

The dating confidently showed the site was inhabited by Neanderthals roughly 70,000 years ago, and the artifacts showed that these Neanderthals were skilled.

"The bones on this site are very well preserved, and we can see marks of how Neanderthals processed and butchered these animals. Our analysis of the stone artifacts also demonstrates variability in the type of tools produced, indicating Neanderthals' capability to exploit the available resources in the area," Samper Carro says.

"They clearly knew what they were doing. They knew the area and how to survive for a long time."

This should not come as much of a surprise. Neanderthals had been living happily in Europe for around 300,000 years before their extinction.

But the reasons why Neanderthals went extinct are not entirely clear to us. If they had been inflexible in their approach to food availability, that would have been a clue. The fact that they were adaptable can also tell us something about why they died out.

The rapid decline of the Neanderthals after surviving for so long coincided with the arrival of modern humans, a juxtaposition that does not bode well for the role of our own species in their disappearance. It could very well be the work of Homo sapiens that all we have left of the Neanderthals is a scant artifact record, and traces of DNA in our genome.

Now, we also have Abric Pizarro, and researchers are keen to sift out its secrets, to learn more about the mysterious lives of these long-lost cousins.

"Future studies will characterize the Neanderthal occupations documented in Abric Pizarro in more detail," the authors write.

The research has been published in the Journal of Archaeological Science.

By some estimates, as many as 4 in 5 people diagnosed with Parkinson's disease go on to develop dementia in the next 15 years.

As intimidating as the figure might be, those predictions are often based on studies with numerous limitations and small sample sizes, calling into question just how closely linked these two neurological conditions might be.

New research carried out by researchers from the University of Pennsylvania, suggests that the chances of having dementia 15 years following a Parkinson's diagnosis is more like 50 percent, only reaching 74 percent after 20 years.

That's significantly lower than previous estimates: earlier studies from 2003 and 2008 had put the chance of developing dementia 15-20 years after a Parkinson's diagnosis at roughly 80 percent on average.

"While these studies were important in highlighting the issue of cognitive decline in Parkinson's disease, the studies were conducted many years ago, were relatively small and had other limitations, so we wanted to reevaluate these findings," says Daniel Weintraub, a psychiatrist from the University of Pennsylvania.

The figures are pulled from two separate, ongoing investigations, one involving 417 patients with an average age of 62 at the commencement of the analysis, and one of 389 people with an average age of 69 at the start of monitoring.

As well as finding lower rates of dementia than previous studies had identified, the new research suggests dementia takes longer to develop than experts thought: the first study with the lower average age put the chance of having dementia 10 years after diagnosis at 9 percent, while in the second study with the higher average age it was 27 percent.

Just why each study disagreed so drastically isn't clear, though the researchers suspect it may have something to do with how recently each sample in the two studies had received their Parkinson's diagnosis, and the state of their treatment on recruitment.

In either case, the relatively slower rates of decline implies specialists might have more time for dementia treatments to take effect and for preparations to be put in place. It also means there's more hope for those with Parkinson's that their risk of also developing dementia is lower and less pressing than some studies suggest.

"These results provide more hopeful estimates of the long-term risk of dementia for people with Parkinson's disease, suggesting that there is a longer window to intervene to prevent or delay cognitive decline," says Weintraub.

This is of course a complex issue, and many different factors are involved in determining an individual's risk: the researchers found that an older age of Parkinson's diagnosis, being male, and having a lower education level all increased the risk of developing dementia, which only add to multiple other known factors.

Future research should look at bigger, more diverse groups of people, the authors of this latest study say, and the team is keen to see more data on cognitive abilities collected in people who are living with Parkinson's.

For now, it's an encouraging step forward in our understanding of this devastating disease, suggesting that the damage it causes in the brain isn't as closely linked to dementia as we previously thought.

"The development of dementia is feared by people with Parkinson's, and the combination of both a movement disorder and a cognitive disorder can be devastating to them and their loved ones," says Weintraub.

The research has been published in Neurology.

Horses participating in a new experiment revealed an unexpected level of smarts by appearing to strategically ignore game rules to reap the most treats for the least amount of effort.

"Horses are not natural geniuses," says Carrie Ijichi, an equine scientist at Nottingham Trent University in England. "They are thought of as mediocre, but this study shows they're not average and are in fact more cognitively advanced than we give them credit for."

Surprisingly few studies have been carried out on horse learning, with some research hinting at the capacity for understanding the basic consequences of their decisions.

Pondering whether the large herbivores err towards living in the moment or have an inkling of what's to come, Nottingham Trent University ethologist Louise Evans and colleagues have just demonstrated what many horse lovers may already suspect: horses can and do plan ahead.

The researchers put 20 horses to the test. The horses were offered a treat for touching a target in the form of a piece of card.

When that target was revealed alongside a light, however, this reward was not provided.

The light was meant to indicate a kind of 'stop' signal. But the horses continued to nose boop the target regardless, gobbling their treats once the light was off.

It's easy to dismiss this behavior as a failure to understand the game. But there are several alternate reasons why our trusty steeds may act this way, Evans and team explain. These include: understanding but lacking the behavioral inhibition to stop – a sign of impatience; taking longer to learn a second signal than the time they were given; or, 'cleverly' applying a cost-benefit strategy.

To distinguish between the options, the researchers introduced a cost to the experiment. The cost was a timeout – removing any possibility of a reward for a period of 10 seconds after the horse incorrectly touched the card whenever the 'stop' light was on.

"We were expecting horses' performance to improve when we introduced the time-out, but were surprised by how immediate and significant the improvement was," says Evans.

"Animals usually need several repetitions of a task to gradually acquire new knowledge, whereas our horses immediately improved when we introduced a cost for errors. This suggests that the horses knew all along what the rules of the game were."

The researchers believe their equine test subjects nudged the targets indiscriminately at first because the horses still received regular rewards without having to put in the effort to assess the light's significance. The horses seemed to use a cost-benefit approach to ignore the stop signal, but as soon as the larger cost was imposed they switched tactics, indicating a level of forward planning previously thought beyond them.

This demonstrates an ability to anticipate future events and alter their behavior to achieve their goal: in this case, more treats for minimal effort.

"We now think that horses may be able to use a form of learning called 'model-based learning' which was thought to be too complex for them. This will now help us to understand their behavior and capabilities much better," explains Ijichi.

"It's fascinating because they have a very underdeveloped prefrontal cortex which is what we typically credit with producing that type of thinking in humans. This means they must be using another area of the brain to achieve a similar result and this teaches us that we shouldn't make assumptions about animal intelligence or sentience based on whether they are 'built' just like us."

This is a common mistake we seem to have repeated across many animal species from bees to birds and primates, in part due to misguided attempts at avoiding anthropomorphizing them.

But our own mighty thinking abilities as humans did not just conveniently appear from nowhere. Their origins lie deep within our evolutionary history so we likely share many cognitive traits with a lot of other species.

By better understanding how other animals think we can strengthen our relationships with them and improve the welfare of the other life we share our planet with.

This research was published in Applied Animal Behaviour Science.

The world's climate is teetering on the brink, and no one knows which way it will fall.

A new model of Earth's climate system suggests that if global warming surpasses the main goal of the Paris Agreement, it could set off a series of tipping points from which it will be very hard, if not impossible, to return.

On our current climate trajectory, the risk of surpassing one of four tipping points by 2300 could reach 45 percent.

The findings come at a critical point in the climate crisis.

Last year, for the very first time, all 365 days in the year exceeded 1°C above pre-industrial levels, bringing the planet uncomfortably close to exceeding the Paris Agreement threshold of 1.5 °C of warming above pre-industrial levels.

Some experts think our decisions in the next few years will make or break that goal. Others argue we overshot it years ago.

The current research was led by climate scientists, Tessa Möller and Annika Ernest Högner, at the University of Potsdam in Germany.

It investigates four possible points of 'no return' – when parts of the climate system reach a critical threshold that leads to even more severe and rapid climate change.

These include the collapses of the Atlantic Ocean's main current system, the Amazon rainforest, the Greenland ice sheet, and the West Antarctic Ice Sheet.

Experts have recently warned that the Atlantic Ocean current system could collapse as soon as 2050.

What's more, Greenland's melting ice sheet is unnervingly close to hitting a point of no return – if it hasn't already.

Biosphere systems like the Amazon rainforest could also shift the climate system in catastrophic ways. Some scientists think the rainforest is already spewing more carbon than it absorbs, contributing to global warming instead of alleviating it.

The probability that just one of these thresholds is crossed is defined as the 'tipping risk'.

"We find that tipping risk by 2300 increases with every additional 0.1 °C of overshoot above 1.5 °C and strongly accelerates for peak warming above 2.0 °C," the authors of the study conclude.

While these projections are for a distant future, it's what we do now that will determine our course. The findings underline just how important it is to stick to the Paris Agreement and keep warming well below 2 °C, even if the 1.5 °C target is surpassed.

If global temperatures pass the 1.5 °C threshold, even temporarily, there may be no turning back.

Like dominoes, one falling tipping point might trigger another to fall, and it's unclear whether the individual thresholds can be reversed or slowed.

Using a conceptual model that takes this complexity into account, Möller, Högner, and their team have assessed the threat of tipping risks in the short term (by 2100), the medium term (until 2300), and the long term (after 50,000 years).

At the world's current rate of warming, models show that by 2300, the tipping risk could reach 45 percent, and in the long term, it could nearly double to 76 percent.

And that's only considering four tipping points.

While the authors admit there is "considerable uncertainty" in current climate models, it remains crucial that scientists keep trying to predict what happens if the world overshoots our climate goals.

"The transient nature of an overshoot might offer a window of opportunity to counteract anthropogenic emissions with rapid interventions and stabilize the ice sheets before tipping is locked-in," explains the international team of researchers.

Getting to net zero greenhouse gas emissions by 2100 will be "paramount to minimize tipping risk in the long term," the team adds.

The stability of our planet's climate system is at stake.

The study was published in Nature Communications.

Two giant clusters of galaxies observed in the process of colliding are going so hard that their dark matter has basically detached from normal matter and flown ahead.

It's like untethered cargo during a collision between two vehicles. Other forces stop the vehicles themselves, but the cargo, under the influence of momentum, keeps going.

It's not the first time we've seen dark matter decouple from normal matter in the course of a giant cosmic collision, but we've never seen it in quite this fashion. And the finding, scientists hope, may give us new clues about the behavior and properties of the mysterious dark matter that dominates the Universe.

Dark matter is one of the great mysteries of the Universe. We don't know what it is; nor can we detect it directly.

But there is, somehow, more gravity out there in the cosmos than we expect there to be, based on the "normal" matter that we can detect. A lot more gravity. We observe it in the motions of stars and galaxies, and in the way space-time itself bends and warps in the presence of powerful gravitational fields.

According to scientists' calculations, only about 15 percent of the matter budget of the Universe is normal matter. The remaining 85 percent or so is this invisible, untouchable dark matter that only seems to interact with normal matter through gravity.

And it's everywhere. Normal matter galaxies, such as our own, exist within giant blobs of dark matter. Vast strands of it make up what we call the cosmic web, gravitationally connecting galaxies to galaxies, clusters to clusters, providing routes normal matter can travel to meet, collide, and grow.

Normal matter has many other ways of interacting with other stuff, so massive events – such as collisions between clusters of galaxies – can get interesting. By and large, the galaxies within the clusters will be fine, but there are vast clouds of gas in the intracluster, intergalactic space that collide with each other, becoming hot and turbulent.

As that normal matter interacts electromagnetically, and as they experience shock and turbulence, a braking effect is applied, causing the clusters to slow down. But the dark matter is unaffected by these slowing influences, and keeps going, bounding ahead before eventually settling back into position around the newly merged cluster.

The merging clusters are collectively known as MACS J0018.5+1626, and they are oriented in such a way that allows for a new measurement of the velocities of matter within them.

A previous measurement was conducted on a cluster collision we are viewing side-on; MACS J0018.5+1626 is oriented so that one cluster appears to be heading directly towards us, and the other directly away.

The researchers used different techniques to measure the speeds of dark and normal matter.

The dark matter velocity was determined by measuring the speed of the galaxies within the clusters, based on how the light is stretched or compressed towards red or blue as it moves away from or towards us. This is known as the Doppler shift, and it's a reliable way of measuring velocity in space.

The cluster member galaxies' speed acts as a proxy for the dark matter's speed, since galaxies and dark matter behave similarly during a cluster collision.

To measure the speed of the intracluster medium, the team relied on something called the Sunyaev-Zeldovich effect. This is a distinct warping seen in the background light of the Universe, caused by electrons in a volume of space. Since these electrons can scatter light, this effect can be used to determine how densely the electrons are packed.

A secondary effect can be observed if the scattering medium is moving, and scientists can analyze this effect to determine how the medium is moving: how fast, and in which direction.

This allowed the researchers to determine the velocity of the normal matter in the clusters, observing a distinct velocity difference between it and the dark matter as revealed by the galaxies.

It's a very thorough work of astrophysical science that may aid us in our quest to understand exactly what the heck dark matter is.

"This study is a starting point to more detailed studies into the nature of dark matter," Silich says. "We have a new type of direct probe that shows how dark matter behaves differently from normal matter."

The research has been published in The Astrophysical Journal.

Most need no reminder that motherhood is constrained by a biological clock – it's a fact that keeps many women awake at night, governs career and relationship choices, and contributes a lion's share to the US$819 million IVF industry.

But mature fatherhood comes with its own risks, and a new study finds the proportion of US fathers aged 50 or older at the time of their child's birth is on the rise, meaning more children are likely to be impacted.

The reasons for this trend are unclear, but Stanford University urologist Albert Ha and colleagues note it's often attributed to "diminished concerns of the male 'biological clock' and the desire for educational and financial stability prior to starting a family."

"Previous studies have also highlighted the influence of evolving gender norms that promote active parental involvement while emphasizing traditional roles like the male 'breadwinner'," the authors add.

In a world where the focus is usually squarely on the mother, the researchers are concerned that public awareness of these "modest but significant" risks associated with advanced paternal age (APA) is lacking.

A 2018 study identified many of the risks of mature fatherhood, using data from 2007 to 2016 for more than 40 million live births in the US.

The data revealed that babies born to fathers over the age of 35 were at higher risk for adverse outcomes like low birth weight, seizures, and breathing problems immediately after birth.

And the older a father was, the greater the risk – for a man aged 45 years or older, his baby was 14 percent more likely to be born prematurely, and for a man aged 50 or older, his child was 28 percent more at risk of being admitted to neonatal intensive care.

Ha and colleagues analyzed the more than 46 million live births reported in the US from 2011 to 2022. Their cross-sectional study highlights that the proportion of US families affected by these risks is rising as more men opt in to parenthood at a mature age.

The average paternal age rose steadily from 30.8 years in 2011 to 32.1 years in 2022, and the proportion of births involving fathers aged 50 or older increased from 1.1 percent in 2011 to 1.3 percent in 2022. It's a small but significant uptick.

"Recent socioeconomic and demographic trends have shifted the timeline for family building in the US, with many couples increasingly delaying parenthood," Ha and colleagues write.

Even after controlling for maternal age and other factors, every 10-year increase in the father's age increased the proportion of births that relied on assisted reproductive technology (ART). It was also associated with a higher likelihood of being the mother's first birth, and an increased risk of preterm birth and low birth weight compared to fathers aged 30 to 39.

"Paternal age has also affected fertility, pregnancy trajectory, and child health," the authors write.

"Age-related conditions, such as erectile dysfunction and hypogonadism, impair paternal fecundity, while older age is associated with decreased semen volume, motility, and morphology."

Research has also linked older paternal age to declines in sperm quality, meaning the squiggly little gene packets that contribute half of a baby's DNA are more likely to be affected by DNA fragmentation, abnormal chromosome numbers, new mutations, and epigenetic alterations.

"Overall, the accumulation of alterations in older men may increase the risk of conditions like autism, pediatric cancers, achondroplasia, and schizophrenia; decrease likelihood of ART success; and heighten risk of perinatal complications," the authors write.

There were no significant differences found in infant sex ratio based on a father's age, except among fathers aged 70 years or older, who were more likely to have a female baby.

Ultimately, the research highlights the need for better awareness of the risks of mature fatherhood, and further investigation into the factors driving this societal shift.

This research is published by JAMA Network Open.

A spoonful of sugar may help the medicine go down, but according to two new studies, a spoonful of honey might do something even better.

Adding one or two tablespoons of honey to a serving of unsweetened yogurt could boost the latter's probiotic powers, the new studies suggest, by helping beneficial bacteria from yogurt survive their odyssey into our digestive systems.

"We were interested in the culinary pairing of yogurt and honey, which is common in the Mediterranean diet, and how it impacts the gastrointestinal microbiome," says co-author Hannah Holscher, a nutrition scientist at the University of Illinois Urbana-Champaign.

The Mediterranean diet is associated with a suite of health benefits, commonly attributed to the presence of healthy fats from fish, olive oil, and nuts, as well as reduced emphasis on red meat.

Dairy doesn't play a big role overall, but there are exceptions – namely for cheese and yogurt. And dating back at least to the ancient Greek dairy product oxygala, many Mediterranean traditions employ honey as a yogurt sweetener.

Based on existing knowledge about yogurt and honey, Holscher and her colleagues wanted to see if honey is more than just a sweetener in this role.

Some types of yogurt are supplemented with probiotic bacterial strains such as Bifidobacterium animalis, a natural resident of many animals' gastrointestinal tracts – including ours – that previous research has linked with improved gastrointestinal health and immune function in humans.

Honey is famous for its antibacterial properties, but it's also a prebiotic; an agent that promotes the growth or activity of helpful microbes within the eater's body.

Given its potential for boosting beneficial bacteria, the researchers hoped to learn if honey might help those bacteria endure the dangers they face inside a human digestive system.

"The enzymes in our mouth, stomach, and intestines help with digestion and facilitate nutrient absorption, but they also reduce the viability of microbes," Holscher says.

"That's great when it's pathogens, but not necessarily when it comes to beneficial bacteria," she explains. "We wanted to see if honey could help probiotic bacteria survive in the gut."

In the first of two new studies, researchers conducted lab experiments to investigate how four honey varietals – alfalfa, buckwheat, clover, and orange blossom – affect the viability of B. animalis in yogurt amid simulated digestion.

They mixed yoghurt innoculated with the bactreria into one of the four honey varietals, and then allowed the bacteria to grow on petri dishes while being exposed to solutions simulating one of several fluids they might encounter in our guts: saliva, stomach acid, intestinal bile, and enzymes.

None of the four honey types showed a significant effect on the bacteria's survival in saliva or stomach acid, the researchers report, with outcomes similar to those of control groups, which featured yogurt mixed with sugar or water.

In solutions designed to mimic intestinal fluids, however, yogurt mixed with honey did seem to support the survival of beneficial bacteria. The effect was most pronounced with a clover varietal, the study found.

The researchers made their initial findings in a randomized, controlled crossover trial based on 62 healthy adult humans. They asked the participants to eat two different items for two weeks each: yoghurt with clover honey for one fortnight, and heat-treated yoghurt for the other.

A follow-up trial had 36 of these participants continue to a third round in the sequence, in which they ate yoghurt mixed with sugar.

Participants submitted stool samples as well as information about their bowel movements, and also filled out questionnaires and performed tasks to evaluate their mood, cognition, and overall well-being.

"Our findings showed that pairing honey with yogurt supported the survival of the yogurt's probiotic bacteria in the gut, so the lab study results did translate to real-world application in humans," Holscher says.

The study did not find changes in intestinal transit time, frequency of bowel movements, mood, or cognition. But that may simply reflect the general health of the participants, Holscher notes, and hardly precludes the need for further research.

It's worth noting honey is still sugar, with the associated health risks, and the study's authors are not suggesting a Winnie-the-Pooh approach.

"We found that one tablespoon of honey in a serving of yogurt helps support probiotic survival. However, we have to keep in mind that honey is an added sugar, and most Americans need to be cognizant of the amount of sugar in their diet to maintain a healthy body weight," Holscher says.

While there is substantial research pointing to the potential boon of probiotics, it's also worth mentioning probiotic supplements are not for everyone, and can pose dangers of their own.

In general, however, Holscher says this research hints at hidden wisdom behind the ancient tradition of mixing honey and yogurt.

"Adding a little bit of honey to unsweetened yogurt is a nice culinary pairing to incorporate into your menu rotation," she says.

The studies were published in The Journal of Nutrition.

A case study of a 62-year-old man in the US provides a prime example of why it's so important to keep a close eye on rapid weight loss while juggling medications.

At 132 kg (291 lbs), the man qualified as obese, a factor that may have contributed to his development of type 2 diabetes and may have been linked closely with another of his conditions, an underactive thyroid gland.

Consequently his family doctor prescribed him with daily insulin injections, as well as a daily dose of a thyroid hormone replacement drug called levothyroxine. He was also told to take a weekly dose of the diabetes and weight loss drug tirzepatide (sold under the brand name Zepbound).

Tirzepatide is one of a growing number of popular weight loss drugs that mimic the hormones GLP-1 (glucagon-like peptide-1) and GIP (gastric inhibitory polypeptide) to manage blood sugar levels and appetite.

The treatment was so effective the man's weight dropped by 39 kg (86 lbs), or almost 30 percent of his body weight, in just six months.

Unfortunately, his weight loss came with a sting in the tail. Shortly after, the man presented himself to an emergency department suffering from "palpitations, excessive sweating, confusion, fever, and hand tremors", according to the case study written up by a team from the University of Colorado.

After getting checked out, it was revealed that the palpitations were a sign of atrial fibrillation; an irregular heartbeat condition that can trigger strokes and heart attacks. Further tests showed this had been brought on by thyrotoxicosis, which is an overabundance of a hormone produced by the thyroid.

Or, in this case, a medication designed to look just like it.

Dosages for many medications are weight based. So as the man lost weight, the relative dosage of levothyroxine crept higher. At his initial weight he was takening 1.5 μg per kilogram of his weight. By the end that had inadvertantly jumped to 2.15 μg per kilogram.

All of this could have been prevented if the man had adjusted his other medications in relation to his changing weight. The levothyroxine should have been adjusted as his weight changed to avoid the thyrotoxicosis and atrial fibrillation, according to the case study authors.

The man also missed a scheduled follow-up appointment with his doctor due to traveling, which may have played a part in this lapse in monitoring.

Losing a lot of weight quickly does come with potential risks, as well as all the health benefits, and previous studies have shown it's important to maintain good health in other areas while trying to shed the pounds.

Tirzepatide has proved very effective in tackling obesity – but when it comes to any extreme weight loss strategy, patients (and their existing medications) need to be closely monitored to prevent other health problems from arising.

"With the increasing use of tirzepatide and other GLP-1 analogues for the treatment of patients with obesity, we recommend evaluating patients using tirzepatide closely (every 4 to 6 weeks initially) for assessment of therapy response, adverse events, and possible dose adjustment of other concomitant medications," write the case study authors.

The research has been published in JAMA Internal Medicine.

For roughly one in every hundred people, food containing even the smallest amounts of gluten can deliver a gutful of hurt.

While a domino effect of immunological reactions can be traced back to their genetic roots, a number of contributing factors are also involved, making it difficult to map the precise chain of events that causes a reaction to gluten to emerge.

Using transgenic mice, an international team led by scientists from McMaster University in Canada has identified a crucial role played by the very cells making up the gut's lining, describing a major stepping stone that could lead to new therapies.

Celiac disease is in essence an autoimmune disorder triggered by the presence of a group of structural proteins known as gluten in the intestines.

Eating virtually anything made with wheat, barley, or rye – meaning most baked goods, breads, and pastas – puts people with the condition at risk of bloating, pain, diarrhea, constipation, and sometimes reflux and vomiting.

Currently the only way to avoid the symptoms is to avoid the foods that trigger them.

"The only way we can treat celiac disease today is by fully eliminating gluten from the diet," says McMasters gastroenterologist Elena Verdu. "This is difficult to do, and experts agree that a gluten-free diet is insufficient."

Around 90 percent of people diagnosed with the condition carry a pair of genes that encode for a protein called HLA-DQ2.5. Of the remaining 10 percent, most have a similar protein called HLA-DQ8.

Like other kinds of 'HLA' (or human leukocyte antigen) proteins, the proteins hold pieces of fallen invaders aloft like macabre trophies on a class of immune cells, warning other defensive tissues to be on the lookout.

In the specific case of HLA-DQ2.5 and HLA-DQ8, the proteins are shaped to hold chunks of gluten peptide that are resistant to digestion, instructing murderous T cells to go on the hunt.

Unfortunately, these instructions aren't the clearest at distinguishing between a threat and similar-looking materials in our body, meaning those with the genes are at risk of a variety of autoimmune conditions.

Not everybody who expresses either HLA-DQ2.5 or HLA-DQ8 will develop an immune disorder like celiac disease, however. For that to happen, those torn-up pieces of gluten first need to be carried across the gut wall by a transporting enzyme that binds with the peptide and alters it in ways to make it even more recognizable.

Cells in the intestinal wall are responsible for releasing this transporting enzyme into the gut, so they clearly have a critical role in the early stages of the disease. They are also known to express the family of proteins to which HLA-DQ2.5 and HLA-DQ8 belong, which are typically regulated by inflammatory responses in the gut.

What hasn't been clear is how this staging ground for people with celiac disease actually functions within the pathology itself.

To focus on this important link in the chain, the research team double-checked the expression of the major immune complex in the cells lining the intestines of people with treated and untreated celiac disease, and in mice with the human genes for HLA-DQ2.5.

They then created functional living models of the gut, called an organoid, using the mouse intestinal cells in order to study the expression of their immune proteins up close, subjecting them to inflammatory triggers as well as predigested and intact gluten.

"This allowed us to narrow down the specific cause and effect and prove exactly whether and how the reaction takes place," says McMasters biomedical engineer Tohid Didar.

From this it became evident the cells lining the gut weren't just passive bystanders suffering collateral damage in a misguided effort to rid the body of gluten – they were key agents, presenting a mash-up of gluten fragments broken down by gut bacteria and transporting enzymes to gluten-specific immune cells first hand.

Knowing the types of tissue involved and their enhancement by the presence of inflammatory microbes gives researchers a new list of targets for future treatments, potentially allowing millions of people worldwide to enjoy a gluten-filled pastry or two without the risk of discomfort.

This research was published in Gastroenterology.

Wherever a cat wanders, it seems to carry an attitude of indifference along with it. Our feline pets are famous for their detached, stand-offish ways, but despite their unfazed, grumpy expressions, they are not always as cold-hearted as their reputation suggests.

A new study has found that when a fellow household pet dies, surviving cats show grief-like signs that are similar to those of dogs.

"Our results are consistent with the idea that cats may experience the loss of companion animals in ways similar to what dogs experience despite having evolved from a less social ancestor," write psychologists Brittany Greene and Jennifer Vonk from Oakland University in the US.

The researchers suggest this could change how we think of cats as asocial and aloof.

Their findings come from an online survey of 412 pet owners, who were the current caregivers for a living cat but who had also had a dog or a cat in the household that had recently died.

In the weeks and months following the loss of their pet, caregivers reported altered behavior in their surviving cats. These included increased vocalizations, time spent looking or sniffing for the deceased pet, and a decreased willingness to eat, sleep, or play.

The more time the surviving cat spent with the deceased pet, the more likely they were to show immediate and long-term behavioral changes "in the direction that would be expected if cats were capable of grief-like responses," write Greene and Vonk.

Even when the deceased pet was a dog, the cats seemed to care that they were gone.

Pet owners in the survey claimed their cats showed temporary signs of confusion or fearfulness after the death of a dog, such as time spent hiding, or sniffing out the deceased pet's favorite spots.

"Cats did not respond significantly differently to the loss of a companion dog or another cat," write Greene and Vonk.

This changed behavior could, therefore, be a possible sign of a lost friend, or as the researchers put it in an ever-so-cat-like way, "an interspecific 'preferred associate'."

The findings align with a similar study, conducted in 2016, which found that in the six months or so after the death of a fellow pet, both cats and dogs increased their attention-seeking behaviors, such as the frequency and volume of their vocalizations. They also ate less.

Grief is a tricky emotion to objectively measure in non-human animals, but these behavioral changes suggest the loss of a pet has an impact on remaining pets in the household.

Either that or pet owners are projecting their own grief onto their cats and dogs.

After all, the findings of the current survey are only based on the perceptions of cat owners.

Caregivers who themselves reported greater grief after losing a pet, were more likely to report their surviving cats as spending more time alone, sleeping, or hiding.

Maybe that's because those who are closer to their pets are better at 'reading' their emotions. Or it could be a sign that a pet owner is only seeing the emotions they want to see in their pet.

Further research, with more objective methods of emotional analysis, is needed to figure out what is driving these observed behavioral changes.

Scientists are still trying to figure out how cats communicate with us, and the nuances of their many vocalizations, gestures, and expressions can be easily misinterpreted.

"Despite some limitations, the current study adds to the very limited data on social cognition of cats," conclude Greene and Vonk.

The study was published in Applied Animal Behaviour Science.