Exoplanet may reveal secrets about the edge of habitability

How close can a rocky planet be to a star, and still sustain water and life? A recently discovered exoplanet may be key to solving that mystery.

"Super-Earth" LP 890-9c (also named SPECULOOS-2c) is providing important insights about conditions at the inner edge of a star's habitable zone and why Earth and Venus developed so differently, according to new research led by Lisa Kaltenegger, associate professor of astronomy at Cornell University.

Her team found LP 890-9c, which orbits close to the inner edge of its solar system's habitable zone, would look vastly different depending on whether it still had warm oceans, a steam atmosphere, or if it had lost its water -- assuming it once had oceans like Earth's.

"Looking at this planet will tell us what's happening on this inner edge of the habitable zone -- how long a rocky planet can maintain habitability when it starts to get hot," Kaltenegger said. "It will teach us something fundamental about how rocky planets evolve with increasing starlight, and about what will one day happen to us and Earth."

Kaltenegger is the lead author of "Hot Earth or Young Venus? A Nearby Transiting Rocky Planet Mystery," published in Monthly Notices of the Royal Astronomical Society: Letters.

LP 890-9c is one of two super-Earths orbiting a red dwarf star located 100 light years from Earth, researchers announced last year. They said liquid water or an atmosphere rich in water vapor was possible on LP 890-9c, which is about 40% larger than Earth and circles the small, cool star in 8.5 days.

Those criteria suggested it to be one of the best targets for JWST to study among the known, potentially habitable terrestrial planets, in addition to the TRAPPIST-1 system.

The team's models are the first to detail differences in the chemical signatures generated by rocky planets near the habitable zone's interior boundary, based on variables including the planet's size, mass, chemical makeup, surface temperature and pressure, atmospheric height and cloud cover. The calculations were key to estimating how much time JWST would need to confirm the basic composition of an atmosphere -- if there is one.

The models span several scenarios thought to reflect stages of rocky planets' evolution, ranging from a "hot Earth" where life might still be possible, to a desolate Venus featuring a carbon dioxide atmosphere. In between are phases Earth is expected to experience as the sun grows brighter and hotter with age, causing the oceans to gradually evaporate and fill the atmosphere with steam before boiling off entirely.

How long those processes might take is unknown, and the astronomers say LP 890-9c provides a rare opportunity to explore that evolution.

"This planet is the first target where we can test these different scenarios," Kaltenegger said. "If it's still a hotter Earth -- hot, but with liquid water and conditions for life -- then the timeline is slower than we thought. If we see that it's already a full-blown Venus, then the water gets lost fast."

It's possible that LP 890-9c has no atmosphere and hosts no life, or that it resembles a Venus with thick clouds that would block light from reflecting and thus yield little information. Deeper investigation promises to provide valuable clues, Kaltenegger said.

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Focus on function helps identify the changes that made us human

Humans split away from our closest animal relatives, chimpanzees, and formed our own branch on the evolutionary tree about seven million years ago. In the time since -- brief, from an evolutionary perspective -- our ancestors evolved the traits that make us human, including a much bigger brain than chimpanzees and bodies that are better suited to walking on two feet. These physical differences are underpinned by subtle changes at the level of our DNA. However, it can be hard to tell which of the many small genetic differences between us and chimps have been significant to our evolution.

New research from Whitehead Institute Member Jonathan Weissman; University of California, San Francisco Assistant Professor Alex Pollen; Weissman lab postdoc Richard She; Pollen lab graduate student Tyler Fair; and colleagues uses cutting edge tools developed in the Weissman lab to narrow in on the key differences in how humans and chimps rely on certain genes. Their findings, published in the journal Cell on June 20th, may provide unique clues into how humans and chimps have evolved, including how humans became able to grow comparatively large brains.

Studying function rather than genetic code

Only a handful of genes are fundamentally different between humans and chimps; the rest of the two species' genes are typically nearly identical. Differences between the species often come down to when and how cells use those nearly identical genes. However, only some of the many differences in gene use between the two species underlie big changes in physical traits. The researchers developed an approach to narrow in on these impactful differences.

Their approach, using stem cells derived from human and chimp skin samples, relies on a tool called CRISPR interference (CRISPRi) that Weissman's lab developed. CRISPRi uses a modified version of the CRISPR/Cas9 gene editing system to effectively turn off individual genes. The researchers used CRISPRi to turn off each gene one at a time in a group of human stem cells and a group of chimp stem cells. Then they looked to see whether or not the cells multiplied at their normal rate. If the cells stopped multiplying as quickly or stopped altogether, then the gene that had been turned off was considered essential: a gene that the cells need to be active-producing a protein product-in order to thrive. The researchers looked for instances in which a gene was essential in one species but not the other as a way of exploring if and how there were fundamental differences in the basic ways that human and chimp cells function.

By looking for differences in how cells function with particular genes disabled, rather than looking at differences in the DNA sequence or expression of genes, the approach ignores differences that do not appear to impact cells. If a difference in gene use between species has a large, measurable effect at the level of the cell, this likely reflects a meaningful difference between the species at a larger physical scale, and so the genes identified in this way are likely to be relevant to the distinguishing features that have emerged over human and chimp evolution.

"The problem with looking at expression changes or changes in DNA sequences is that there are many of them and their functional importance is unclear," says Weissman, who is also a professor of biology at the Massachusetts Institute of Technology and an Investigator with the Howard Hughes Medical Institute. "This approach looks at changes in how genes interact to perform key biological processes, and what we see by doing that is that, even on the short timescale of human evolution, there has been fundamental rewiring of cells."

After the CRISPRi experiments were completed, She compiled a list of the genes that appeared to be essential in one species but not the other. Then he looked for patterns. Many of the 75 genes identified by the experiments clustered together in the same pathways, meaning the clusters were involved in the same biological processes. This is what the researchers hoped to see. Individual small changes in gene use may not have much of an effect, but when those changes accumulate in the same biological pathway or process, collectively they can cause a substantive change in the species. When the researchers' approach identified genes that cluster in the same processes, this suggested to them that their approach had worked and that the genes were likely involved in human and chimp evolution.

"Isolating the genetic changes that made us human has been compared to searching for needles in a haystack because there are millions of genetic differences, and most are likely to have negligible effects on traits," Pollen says. "However, we know that there are lots of small effect mutations that in aggregate may account for many species differences. This new approach allows us to study these aggregate effects, enabling us to weigh the impact of the haystack on cellular functions."

Researchers think bigger brains may rely on genes regulating how quickly cells divide

One cluster on the list stood out to the researchers: a group of genes essential to chimps, but not to humans, that help to control the cell cycle, which regulates when and how cells decide to divide. Cell cycle regulation has long been hypothesized to play a role in the evolution of humans' large brains. The hypothesis goes like this: Neural progenitors are the cells that will become neurons and other brain cells. Before becoming mature brain cells, neural progenitors divide multiple times to make more of themselves. The more divisions that the neural progenitors undergo, the more cells the brain will ultimately contain -- and so, the bigger it will be. Researchers think that something changed during human evolution to allow neural progenitors to spend less time in a non-dividing phase of the cell cycle and transition more quickly towards division. This simple difference would lead to additional divisions, each of which could essentially double the final number of brain cells.

Consistent with the popular hypothesis that human neural progenitors may undergo more divisions, resulting in a larger brain, the researchers found that several genes that help cells to transition more quickly through the cell cycle are essential in chimp neural progenitor cells but not in human cells. When chimp neural progenitor cells lose these genes, they linger in a non-dividing phase, but when human cells lose them, they keep cycling and dividing. These findings suggest that human neural progenitors may be better able to withstand stresses -- such as the loss of cell cycle genes -- that would limit the number of divisions the cells undergo, enabling humans to produce enough cells to build a larger brain.

"This hypothesis has been around for a long time, and I think our study is among the first to show that there is in fact a species difference in how the cell cycle is regulated in neural progenitors," She says. "We had no idea going in which genes our approach would highlight, and it was really exciting when we saw that one of our strongest findings matched and expanded on this existing hypothesis."

More subjects lead to more robust results

Research comparing chimps to humans often uses samples from only one or two individuals from each species, but this study used samples from six humans and six chimps. By making sure that the patterns they observed were consistent across multiple individuals of each species, the researchers could avoid mistaking the naturally occurring genetic variation between individuals as representative of the whole species. This allowed them to be confident that the differences they identified were truly differences between species.

The researchers also compared their findings for chimps and humans to orangutans, which split from the other species earlier in our shared evolutionary history. This allowed them to figure out where on the evolutionary tree a change in gene use most likely occurred. If a gene is essential in both chimps and orangutans, then it was likely essential in the shared ancestor of all three species; it's more likely for a particular difference to have evolved once, in a common ancestor, than to have evolved independently multiple times. If the same gene is no longer essential in humans, then its role most likely shifted after humans split from chimps. Using this system, the researchers showed that the changes in cell cycle regulation occurred during human evolution, consistent with the proposal that they contributed to the expansion of the brain in humans.

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AI reveals hidden traits about our planet's flora to help save species

In a world-first, scientists from UNSW and Botanic Gardens of Sydney, have trained AI to unlock data from millions of plant specimens kept in herbaria around the world, to study and combat the impacts of climate change on flora.

"Herbarium collections are amazing time capsules of plant specimens," says lead author on the study, Associate Professor Will Cornwell. "Each year over 8000 specimens are added to the National Herbarium of New South Wales alone, so it's not possible to go through things manually anymore."

Using a new machine learning algorithm to process over 3000 leaf samples, the team discovered that contrary to frequently observed interspecies patterns, leaf size doesn't increase in warmer climates within a single species.

Published in the American Journal of Botany, this research not only reveals that factors other than climate have a strong effect on leaf size within a plant species, but demonstrates how AI can be used to transform static specimen collections and to quickly and effectively document climate change effects.

Herbarium collections move to the digital world

Herbaria are scientific libraries of plant specimens that have existed since at least the 16th century.

"Historically, a valuable scientific effort was to go out, collect plants, and then keep them in a herbarium. Every record has a time and a place and a collector and a putative species ID," says A/Prof. Cornwell, a researcher at the School of BEES and a member of UNSW Data Science Hub.

A couple of years ago, to help facilitate scientific collaboration, there was a movement to transfer these collections online.

"The herbarium collections were locked in small boxes in particular places, but the world is very digital now. So to get the information about all of the incredible specimens to the scientists who are now scattered across the world, there was an effort to scan the specimens to produce high resolution digital copies of them."

The largest herbarium imaging project was undertaken at the Botanic Gardens of Sydney when over 1 million plant specimens at the National Herbarium of New South Wales were transformed into high-resolution digital images.

"The digitisation project took over two years and shortly after completion, one of the researchers -- Dr Jason Bragg -- contacted me from the Botanic Gardens of Sydney. He wanted to see how we could incorporate machine learning with some of these high-resolution digital images of the Herbarium specimens."

"I was excited to work with A/Prof. Cornwell in developing models to detect leaves in the plant images, and to then use those big datasets to study relationships between leaf size and climate," says Dr Bragg.

"Computer vision" measures leaf sizes

Together with Dr Bragg at the Botanic Gardens of Sydney and UNSW Honours student Brendan Wilde, A/Prof. Cornwell created an algorithm that could be automated to detect and measure the size of leaves of scanned herbarium samples for two plant genera -- Syzygium (generally known as lillipillies, brush cherries or satinas) and Ficus (a genus of about 850 species of woody trees, shrubs and vines).

"This is a type of AI is called a convolutional neural network, also known as Computer Vision," says A/Prof. Cornwell. The process essentially teaches the AI to see and identify the components of a plant in the same way a human would.

"We had to build a training data set to teach the computer, this is a leaf, this is a stem, this is a flower," says A/Prof. Cornwell. "So we basically taught the computer to locate the leaves and then measure the size of them.

"Measuring the size of leaves is not novel, because lots of people have done this. But the speed with which these specimens can be processed and their individual characteristics can be logged is a new development."

A break in frequently observed patterns

A general rule of thumb in the botanical world is that in wetter climates, like tropical rainforests, the leaves of plants are bigger compared to drier climates, such as deserts.

"And that's a very consistent pattern that we see in leaves between species all across the globe," says A/Prof. Cornwell. "The first test we did was to see if we could reconstruct that relationship from the machine learned data, which we could. But the second question was, because we now have so much more data than we had before, do we see the same thing within species?"

The machine learning algorithm was developed, validated, and applied to analyse the relationship between leaf size and climate within and among species for Syzygium and Ficus plants.

The results from this test were surprising -- the team discovered that while this pattern can be seen between different plant species, the same correlation isn't seen within a single species across the globe, likely because a different process, known as gene flow, is operating within species. That process weakens plant adaptation on a local scale and could be preventing the leaf size-climate relationship from developing within species.

Using AI to predict future climate change responses

The machine learning approach used here to detect and measure leaves, though not pixel perfect, provided levels of accuracy suitable for examining links between leaf traits and climate.

"But because the world is changing quite fast, and there is so much data, these kinds of machine learning methods can be used to effectively document climate change effects," says A/Prof. Cornwell.

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New research reveals the impact of different species and their traits on human wellbeing

New research has revealed for the first time that well-functioning ecosystems are crucial to human health and wellbeing, with human-biodiversity interactions delivering wellbeing gains equating to substantial healthcare cost-savings, when scaled-up across populations.

The University of Kent-led study, which is part of the European Research Council-funded project 'Relating Subjective Wellbeing to Biodiversity' (RELATE), set out to understand which components of nature and biodiversity played a particular role in human wellbeing.

The team, which was led by Kent's Professor Zoe Davies, analysed the effects of species' traits, based on people's feedback following a series of workshops, to identify those that generate different types of wellbeing e.g., physical, emotional, cognitive, social, spiritual, and 'global', the latter being akin to 'whole-person health'.

The team found that, in general, the vast majority of species and traits are beneficial to human wellbeing. They also discovered that each species may support multiple traits, potentially with different impacts. For example, the colours of brambles (black, pink, red) are linked to multiple positive physical, emotional and social wellbeing types, but their prickly texture generated negative emotional wellbeing. The numerous traits from across an ecological community can elicit a multitude of wellbeing responses, illustrating the true complexity of how people relate to biodiversity.

Professor Davies, a biodiversity conservationist at Kent's Durrell Institute of Conservation and Ecology (DICE), said: 'While we know that spending time in natural environments can improve our health and wellbeing, we still need to know more about which species, or traits of species (such as colours, sounds, smells, textures and behaviours), deliver these benefits -- and how people's relationships with biodiversity are both contextually and culturally specific. Understanding how people experience biodiversity is therefore key to successfully managing biodiversity to facilitate human wellbeing.'

Study co-author, Professor Martin Dallimer, from the School of Earth and Environment, University of Leeds, said: 'For the first time, through analysing people's own words and reflections, we are able to explicitly link that feeling of wellbeing with species and their traits. How people respond to biodiversity is hugely varied and if we want people's wellbeing to benefit from spending time in nature, then it is essential to make sure we are maintaining and restoring high quality biodiverse spaces for wildlife and for people. Our aim is that these findings really drive home how important biodiversity is in underpinning wellbeing benefits, particularly to healthcare and public sectors who include 'spending time in nature' as an element of mental health and wellbeing.'

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Navigating underground with cosmic-ray muons

Superfast, subatomic-sized particles called muons have been used to wirelessly navigate underground in a reportedly world first. By using muon-detecting ground stations synchronized with an underground muon-detecting receiver, researchers at the University of Tokyo were able to calculate the receiver's position in the basement of a six-story building. As GPS cannot penetrate rock or water, this new technology could be used in future search and rescue efforts, to monitor undersea volcanoes, and guide autonomous vehicles underground and underwater.

GPS, the global positioning system, is a well-established navigation tool and offers an extensive list of positive applications, from safer air travel to real-time location mapping. However, it has some limitations. GPS signals are weaker at higher latitudes and can be jammed or spoofed (where a counterfeit signal replaces an authentic one). Signals can also be reflected off surfaces like walls, interfered with by trees, and can't pass through buildings, rock or water.

By comparison, muons have been making headlines in recent years for their abilityto help us look deep inside volcanoes, peek through pyramids and see inside cyclones. Muons fall constantly and frequently around the world (about 10,000 per square meter per minute) and can't be tampered with. "Cosmic-ray muons fall equally across the Earth and always travel at the same speed regardless of what matter they traverse, penetrating even kilometers of rock," explained Professor Hiroyuki Tanaka from Muographix at the University of Tokyo. "Now, by using muons, we have developed a new kind of GPS, which we have called the muometric positioning system (muPS), which works underground, indoors and underwater."

MuPS was initially created to help detect seafloor changes caused by underwater volcanoes or tectonic movement. It uses four muon-detecting reference stations aboveground to provide coordinates for a muon-detecting receiver underground. Early iterations of this technology required the receiver to be connected to a ground station by a wire, greatly restricting movement. However, this latest research uses high-precision quartz clocks to synchronize the ground stations with the receiver. The four parameters provided by the reference stations plus the synchronized clocks used to measure the muons' "time-of-flight" enables the receiver's coordinates to be determined. This new system is called the muometric wireless navigation system (MuWNS).

To test the navigation ability of MuWNS, reference detectors were placed on the sixth floor of a building while a "navigatee" took a receiver detector to the basement floor. They slowly walked up and down the corridors of the basement while holding the receiver. Rather than navigating in real time, measurements were taken and used to calculate their route and confirm the path they had taken.

"The current accuracy of MuWNS is between 2 meters and 25 meters, with a range of up to 100 meters, depending on the depth and speed of the person walking. This is as good as, if not better than, single-point GPS positioning aboveground in urban areas," said Tanaka. "But it is still far from a practical level. People need one-meter accuracy, and the key to this is the time synchronization."

Improving this system to enable real-time, meter-accurate navigation hinges on time and money. Ideally the team wants to use chip-scale atomic clocks (CSAC): "CSACs are already commercially available and are two orders of magnitude better than the quartz clocks we currently use. However, they are too expensive for us to use now. But, I foresee that they will become much cheaper as the global demand for CSAC for cellphones increases," said Tanaka.

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Scientists unearth 20 million years of 'hot spot' magmatism under Cocos plate

Ten years ago, Samer Naif made an unexpected discovery in Earth's mantle: a narrow pocket, proposed to be filled with magma, hidden some 60 kilometers beneath the seafloor of the Cocos Plate.

Mantle melts are buoyant and typically float toward the surface -- think underwater volcanoes that erupt to form strings of islands. But Naif's imaging instead showed a clear slice of semi-molten rock: low-degree partial melts, still sandwiched at the base of the plate some 37 miles beneath the ocean floor.

Then, the observation provided an explanation for how tectonic plates can gradually slide, lubricated by partial melting. The study also "raised several questions about why magma is stored in a thin channel -- and where the magma originated from," says Naif, an assistant professor in the School of Earth and Atmospheric Sciences at Georgia Institute of Technology.

Fellow researchers went on to share competing interpretations for the cause of the channel -- including studies that argued against magma being needed to explain the observation.

So Naif went straight to the source.

"I basically went on a multiyear hunt, akin to a Sherlock Holmes detective story, looking for clues of mantle magmas that we first observed in the 2013 Nature study," he says. "This involved piecing together evidence from several independent sources, including geophysical, geochemical, and geological (direct seafloor sampling) data."

Now, the results of that search are detailed in a new Science Advances article, "Episodic intraplate magmatism fed by a long-lived melt channel of distal plume origin," authored by Naif and researchers from the U.S. Geological Survey at Woods Hole Coastal and Marine Science Center, Northern Arizona University, Lamont-Doherty Earth Observatory of Columbia University, the Department of Geology and Geophysics at Woods Hole Oceanographic Institution, and GNS Science of Lower Hutt, New Zealand.

Zeroing in

A relatively young oceanic plate -- some 23 million years old -- the Cocos Plate traces down the western coast of Central America, veering west to the Pacific Plate, then north to meet the North American Plate off the Pacific coast of Mexico.

Sliding between these two plates caused the devastating 1985 Mexico City earthquake and the 2017 Chiapas earthquake, while similar subduction between the Cocos and Caribbean plates resulted in the 1992 Nicaragua tsunami and earthquake, and the 2001 El Salvador earthquakes.

Scientists study the edges of these oceanic plates to understand the history and formation of volcanic chains -- and to help researchers and agencies better prepare for future earthquakes and volcanic activity.

It's in this active area that Naif and fellow researchers recently set out to document a series of magmatic intrusions just beneath the seafloor, in the same area that the team first detected the channel of magma back in 2013.

Plumbing the depths

For the new study, the team combined geophysical, geochemical, and seafloor drilling results with seismic reflection data, a technique used to image layers of sediments and rocks below the surface. "It helps us to see the geology where we cannot see it with our own eyes," Naif explains.

First, the researchers observed an abundance of widespread intraplate magmatism. "Volcanism where it is not expected," Naif says, "basically away from plate boundaries: subduction zones and mid-ocean ridges."

Think Hawaii, where "a mantle plume of hot, rising material melts during its ascent, and then forms the Hawaii volcanic chain in the middle of the Pacific Ocean," just as with the Cocos Plate, where the team imaged the volcanism fed by magma at the lithosphere-asthenosphere boundary -- the base of the sliding tectonic plates.

"Below it is the convecting mantle," Naif adds. "The tectonic plates are moving around on Earth's surface because they are sliding on the asthenosphere below them."

The researchers also found that this channel below the lithosphere is regionally extensive -- over 100,000 square kilometers -- and is a "long-lived feature that originated from the Galápagos Plume," a mantle plume that formed the volcanic Galápagos islands, supplying melt for a series of volcanic events across the past 20 million years, and persisting today.

Importantly, the new study also suggests that these plume-fed melt channels may be widespread and long-lived sources for intraplate magmatism itself -- as well as for mantle metasomatism, which happens when Earth's mantle reacts with fluids to form a suite of minerals from the original rocks.

Connecting the (hot spot) dots

"This confirms that magma was there in the past -- and some of it leaked through the mantle and erupted near the seafloor," Naif says, "in the form of sill intrusions and seamounts: basically volcanoes located on the seafloor."

The work also provides compelling supporting evidence that magma could still be stored in the channel. "More surprising is that the erupted magma has a chemical fingerprint that links its source to the Galápagos mantle plume."

"We learned that the magma channel has been around for at least 20 million years, and on occasion some of that magma leaks to the seafloor where it erupts volcanically," Naif adds.

The team's identified source of the magma, the Galápagos Plume, "is more than 1,000 kilometers away from where we detected this volcanism. It is not clear how magma can stay around in the mantle for such a long time, only to leak out episodically."

Plume hunters wanted

The evidence that the team compiled is "really quite subtle and requires a detailed and careful study of a suite of seafloor observations to connect the dots," Naif says. "Basically, the signs of such volcanism, while they are quite clear here, also require high resolution data and several different types of data to be able to detect such subtle seafloor features."

So, "if we can see such subtle clues of volcanism here," Naif explains, "it means a similar, careful analysis of high resolution data in other parts of the seafloor may lead to similar discoveries of volcanism elsewhere, caused by other mantle plumes."

"There are numerous mantle plumes dotted across the planet. There are also numerous seamounts -- at least 100,000 of them! -- covering the seafloor, and it is anyone's guess how many of them formed in the middle of the tectonic plates because of magma sourced from distant mantle plumes that leaked to the surface."

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Face of Anglo-Saxon teen VIP revealed with new evidence about her life

The face of a 16-year-old woman buried near Cambridge (UK) in the 7th century with an incredibly rare gold and garnet cross (the 'Trumpington Cross') has been reconstructed following analysis of her skull. The striking image is going on public display for the first time on 21st June,* with new scientific evidence showing that she moved to England from Central Europe as a young girl, leading to an intriguing change in her diet.

Forensic artist Hew Morrison created the likeness using measurements of the woman's skull and tissue depth data for Caucasian females. Without DNA analysis, Morrison could not be sure of her precise eye and hair colour, but the image offers a strong indication of her appearance shortly before she died.

Hew Morrison said: "It was interesting to see her face developing. Her left eye was slightly lower, about half a centimetre, than her right eye. This would have been quite noticeable in life."

New "you are what you eat" isotopic analysis of the young woman's bones and teeth conducted by bioarchaeologists Dr Sam Leggett and Dr Alice Rose, and archaeologist Dr Emma Brownlee, during PhD research at the University of Cambridge also reveals that she moved to England from somewhere near the Alps, perhaps southern Germany, sometime after she turned 7 years old.

Leggett and Rose also found that once the girl had arrived in England, the proportion of protein in her diet decreased by a small but significant amount. This change occurred close to the end of her young life, showing that the period between her migration and burial near Cambridge was tragically short.

Dr Leggett, now at the University of Edinburgh, said: "She was quite a young girl when she moved, likely from part of southern Germany, close to the Alps, to a very flat part of England. She was probably quite unwell and she travelled a long way to somewhere completely unfamiliar -- even the food was different. It must have been scary."

Previous analysis indicated that the young woman had suffered from illness but her cause of death remains unknown. She was buried in a remarkable way -- lying on a carved wooden bed wearing the cross, gold pins (also on display) and fine clothing.

Hers is one of only 18 bed burials ever uncovered in the UK. Her ornate cross, combining gold and garnets (third quarter of the 7th century), is one of only five of its kind ever found in Britain and identifies her as one of England's earliest converts to Christianity and as a member of the aristocracy if not royalty. The best known example of such a cross was found in the coffin of St Cuthbert.

In 597 AD, the pope dispatched St Augustine to England on a mission to convert the pagan Anglo-Saxon kings, a process which continued for many decades.

Dr Leggett said: "She must have known that she was important and she had to carry that on her shoulders. Her isotopic results match those of two other women who were similarly buried on beds in this period in Cambridgeshire.

"So it seems that she was part of an elite group of women who probably travelled from mainland Europe, most likely Germany, in the 7th century, but they remain a bit of a mystery. Were they political brides or perhaps brides of Christ? The fact that her diet changed once she arrived in England suggests that her lifestyle may have changed quite significantly."

Dr Sam Lucy, a specialist in Anglo-Saxon burial from Newnham College, Cambridge, who published the Anglo-Saxon excavations at Trumpington**, said:

"These are intriguing findings, and it is wonderful to see this collaborative research adding to our knowledge of this period. Combining the new isotopic results with Emma Brownlee's research into European bed burials really does seem to suggest the movement of a small group of young elite women from a mountainous area in continental Europe to the Cambridge region in the third quarter of the seventh century.

"Southern Germany is a distinct possibility owing to the bed burial tradition known there. Given the increasingly certain association between bed burial, such cross-shaped jewellery, and early Anglo-Saxon Christianity, it is possible that their movement related to pan-European networks of elite women who were heavily involved in the early Church."

Dr Jody Joy, the exhibition's co-curator, said: "The story of this young woman goes to the very heart of what our exhibition is all about -- new research making visible the lives of people at pivotal moments of Cambridgeshire's history. MAA holds one of Britain's most important collections of Early Medieval archaeology and the Trumpington bed burial is so important. It looks like it still has much more to teach us."

In the exhibition, the 'Trumpington Cross' will be displayed together with the delicate gold and garnet pins connected by a gold chain, which were found near the teenager's neck. These pins probably secured a long veil to an outer garment of fine linen. The pins would have caught the light as she moved.The burial bed's decorativeheadboard will also be exhibited.

* The image and artefacts from the mysterious woman's burial -- discovered in 2012 by the Cambridge Archaeological Unit at Trumpington Meadows on Cambridge's southern limits -- including her famous cross will be unveiled in a major new exhibition at Cambridge's Museum of Archaeology and Anthropology (MAA). 'Beneath Our Feet: Archaeology of the Cambridge Region' will run from 21st June to 14th April 2024.

Read more at Science Daily

Regular napping linked to larger brain volume

Daytime napping may help to preserve brain health by slowing the rate at which our brains shrink as we age, suggests a new study led by researchers at UCL and the University of the Republic in Uruguay.

The study, published in the journal Sleep Health, analysed data from people aged 40 to 69 and found a causal link between habitual napping and larger total brain volume -- a marker of good brain health linked to a lower risk of dementia and other diseases.

Senior author Dr Victoria Garfield (MRC Unit for Lifelong Health & Ageing at UCL) said: "Our findings suggest that, for some people, short daytime naps may be a part of the puzzle that could help preserve the health of the brain as we get older."

Previous research has shown that napping has cognitive benefits, with people who have had a short nap performing better in cognitive tests in the hours afterwards than counterparts who did not nap.

The new study aimed to establish if there was a causal relationship between daytime napping and brain health.

Using a technique called Mendelian randomisation, they looked at 97 snippets of DNA thought to determine people's likelihood of habitual napping. They compared measures of brain health and cognition of people who are more genetically "programmed" to nap with counterparts who did not have these genetic variants, using data from 378,932 people from the UK Biobank study, and found that, overall, people predetermined to nap had a larger total brain volume.

The research team estimated that the average difference in brain volume between people programmed to be habitual nappers and those who were not was equivalent to 2.6 to 6.5 years of ageing.

But the researchers did not find a difference in how well those programmed to be habitual nappers performed on three other measures of brain health and cognitive function -- hippocampal volume, reaction time and visual processing.

Lead author and PhD candidate Valentina Paz (University of the Republic (Uruguay) and MRC Unit for Lifelong Health & Ageing at UCL) said: "This is the first study to attempt to untangle the causal relationship between habitual daytime napping and cognitive and structural brain outcomes. By looking at genes set at birth, Mendelian randomisation avoids confounding factors occurring throughout life that may influence associations between napping and health outcomes. Our study points to a causal link between habitual napping and larger total brain volume."

Dr Garfield added: "I hope studies such as this one showing the health benefits of short naps can help to reduce any stigma that still exists around daytime napping."

The genetic variants influencing our likelihood to nap were identified in an earlier study looking at data from 452,633 UK Biobank participants. The study, led by Dr Hassan Dashti (Harvard University and Massachusetts General Hospital), also an author on the new study, identified the variants on the basis of self-reported napping, and this was supported by objective measurements of physical activity recorded by a wrist-worn accelerometer.

In the new study, researchers analysed health and cognition outcomes for people with these genetic variants as well as several different subsets of these variants, adjusted to avoid potential bias, for instance avoiding variants linked to excessive daytime sleepiness.

Genetic data and magnetic resonance imaging (MRI) scans of the brain were available for 35,080 individuals drawn from the larger UK Biobank sample.

In terms of study limitations, the authors noted that all of the participants were of white European ancestry, so the findings might not be immediately generalisable to other ethnicities.

While the researchers did not have information on nap duration, earlier studies suggest that naps of 30 minutes or less provide the best short-term cognitive benefits, and napping earlier in the day is less likely to disrupt night-time sleep.

Previous research looking at the UK and the Netherlands found that nearly a third of adults aged 65 or over had a regular nap.

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Scientists report 'benchmarks' for extreme space weather

High-energy 'relativistic' electrons -- so-called "killer" electrons -- are a major source of radiation damage to satellites and so understanding their patterns of activity is crucial. Bursts of charged particles and magnetic fields from the Sun can tear open the Earth's magnetic field, giving rise to geomagnetic storms. During these events the number of killer electrons in the outer radiation belt can increase by orders of magnitude and become a significant space weather hazard.

Dr Nigel Meredith of BAS led an international team who analysed 20 years of data from a US GPS satellite to determine the 1 in 10, 1 in 50, and 1 in 100-year event levels. A 1 in 100-year event is an event of a size that will be equalled or exceeded on average once every 100 years.

Satellite operators, manufacturers, insurers, and governments need to prepare and mitigate against the risks posed by these electrons. Society is increasingly reliant on satellites for a variety of applications including communication, navigation, Earth observation and defence. As of April 2022, there were 5,465 operational satellites in Earth orbit, and most are exposed to energetic electrons for at least some of their orbit. In 2021, the overall global space economy generated revenues of $386 billion, an increase of four percent compared to the previous year.

Dr Nigel Meredith, space weather scientist and lead author of the study says:

"The 1 in 100 year event levels reported in this study are important for industry and government. They serve as benchmarks against which to compare other extreme space weather events and to assess the potential impact of an extreme event."

These findings are vitally important to the satellite industry as engineers and operators require realistic estimates of the largest electron fluxes encountered in GPS orbit to prepare for the impacts of these extreme events and to improve the resilience of future satellites. The findings are essential for satellite insurers to help them ensure satellite operators are doing all they can to reduce risk and to evaluate realistic disaster scenarios

The difference between the 1 in 10 year and 1 in 100-year event varies depending on the energy of the electrons and the distance from Earth. These differences are largest at the highest energies furthest from the planet, varying between a factor of 3 and 10 for some of the highest electron energies over 35,000 km from the Earth's surface. Such substantial increases could pose a significant additional risk to satellites operating in this region.

Like weather on our planet, space weather can vary greatly over minutes, days, seasons and the 11-year solar cycle. The researchers found that the majority of these killer electron events occurred during the solar cycle's declining phases -- seen twice during the 20-year period they studied -- but the largest event was elsewhere, showing that extreme events can happen at any time.

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New method traces ancestry of hybrid plants and animals

If you've ever kept a garden, you're probably familiar with hybrids, from disease-resistant tomatoes to Stargazer lilies.

Hybrids -- common in agriculture as well as in nature -- have chromosomes from two or more parent species. In some cases, including strawberries, goldfish and several other species, these disparate parental chromosomes become doubled, a condition known as allopolyploidy.

In "Transposon signatures of allopolyploid subgenome evolution," a recent article published in the journal Nature Communications, Binghamton University Assistant Professor of Biological Sciences Adam Session and Daniel S. Rokhsar, a professor of genetics, evolution and development at the University of California, Berkeley, outline a way to trace these genomes back to the polypoid hybrid's parent species.

Unlike previous methods, which use comparison with related non-hybrid species to decipher polypoid ancestry, the authors' method allows them to discover distinct ancestries by looking at genomic patterns in the hybrid itself.

"Each ancestral genome carries a unique set of repetitive elements," Session explained. "So if we find sets of chromosomes in a polypoid that carry different repetitive elements, that proves hybrid ancestry and allows us to figure out which chromosomes were inherited together coming from the various progenitor species."

In the article, they apply the method to some well-studied cases of polyploid hybrids, such as tobacco, cotton and cyprinid fish, such as goldish and carp. They also use it to tease out the disputed ancestries of other hybrids, including false flax and strawberries.

"In many cases, the ancestors of living polyploids are not known. Using our method, we can figure out the ancestral origin of different chromosomes just by studying the polyploid genome itself, and divide the chromosomes into sets, or 'sub-genomes,' derived from its various ancestors," he said. "In addition to identifying the subgenomes, we can also tell you the order in which they were put together."

Polyploidization -- the duplication of genomes in a hybrid that stabilizes its ancestry -- is much more common in plants than animals, since plants can better tolerate multiple copies of their genomes, Session explained. The process of polyploidization is more involved with animal species, although it does happen in some fish and amphibians. In the case of goldfish, the authors prove for the first time that they share the same duplicated gene sequences as common carp, and thus a common hybrid ancestor.

Polyploidy is unknown in mammals, although hybridization is still possible. Take mules, for instance, which are a hybrid between horses and donkeys: Male mules are effectively sterile, although female mules can mate with either parent species. But without genomic duplication, the distinctive hybrid type cannot be stably propagated.

A tetraploid such as cotton has four copies of each chromosome, two from each of two ancestors, while hexaploids -- such as false flax -- have six chromosomes derived from three parent species. With eight copies of each chromosome, an octoploid such as strawberry ultimately has four ancestral species.

Polyploids have complex biology that is still being deciphered, and figuring out the sub-genome structure of their genomes is a step forward. Over millions of years, the genes contributed by each of the parental species evolve in their new polyploid context. Some redundant genes are lost or inactivated; others can develop new functions or novel interactions with their counterparts in the other sub-genomes. The new work argues that the order in which parental species are added to the emerging polyploid mix in a higher polyploid like strawberry can have profound impact on how these evolutionary processes occur. Sorting out the impact of these duplicated on the evolving polyploid is an ongoing challenge, the authors said.

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