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86 Evolution News Articles
for April 2021
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Nature cares only that you reproduce and raise the kids.
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4-30-21 Bronze Age treasure found in Swedish forest by mapmaker
A man surveying a forest for his orienteering club in western Sweden stumbled on a trove of Bronze Age treasure reckoned to be some 2,500 years old. It includes about 50 items, such as necklaces, bracelets and clothing pins. The cartographer, Thomas Karlsson, said "I first thought it might be a lamp, but when I looked closer I saw that it was old jewellery". Swedish archaeologists say it is very rare to find such a hoard in a forest. Ancient tribes usually left such offerings in rivers or wetlands. The hoard was on the forest floor, next to rocks. It is thought that one or more animals had disturbed the earth, leaving the many items semi-exposed. They have been dated to the period between 750 and 500BC. Mr Karlsson said he had spotted the metallic glint while looking down at a map he was working on. At first he thought the ornaments were copies, as they were in such good condition. Then he emailed a local archaeologist while having a coffee in the forest, regional newspaper Goteborgs-Posten reported. The forest is near the town of Alingsas, about 48km (30 miles) northeast of Gothenburg. Archaeologists describe it as a "depot" find - that is, a hoard deliberately left as an offering to a god or gods, or to invest in life after death. The jewellery "is extremely well preserved", said Prof Johan Ling, lecturer in archaeology at Gothenburg University. "Most of the items can be linked to a woman, or women, of high status," he said, quoted by Goteborgs-Posten. The treasure includes a type of rod used to spur on horses, previously found in neighbouring Denmark, but not in Sweden. Swedish law requires anyone finding such antiquities to notify the police or local authority, as they are regarded as state property. The Swedish National Heritage Board then decides what reward, if any, the finder should receive.

4-30-21 Indigenous people may have left the Amazon before Europeans arrived
Fossil pollen records from the Amazon hint at a surge of regrowth in forests of the Amazon basin around 300 to 600 years before European colonisation of South America, suggesting that Indigenous peoples may have been leaving the region at that time. Following European arrival in South America in the mid-16th century AD, millions of Indigenous people lost their lives in the face of unfamiliar disease, slavery and warfare in an event known as The Great Dying of the Indigenous Peoples of the Americas. Previous studies have shown a dip in carbon dioxide levels in the region in 1610, known as the Orbis spike. This has been associated with the population decline that occurred after Europeans landed in South America, as forests regrew on land previously inhabited by Indigenous people, decreasing carbon dioxide levels. But the pollen record suggests forest regrowth in this region happened earlier. Mark Bush at the Florida Institute of Technology and his colleagues analysed sediment samples from 39 lakes in the Amazon, in Brazil, Peru, Ecuador and Bolivia. They recovered pollen from the lake sediment – the deeper the sediment, the older it is. They found that forest regrowth in the Amazon basin may have begun around 300 to 600 years before the Orbis spike. They didn’t see a pattern of reforestation in the fossil records between 1550 and 1750, following European colonisation. “Between 950 and 1350 AD, there are more sites that are gaining forest than losing forest during that time,” says Bush. This suggests that Indigenous people were abandoning land hundreds of years before Europeans arrived, he says. “These were complex societies, they weren’t just hunter-gatherers,” says Bush. The researchers are unsure about the drivers of this early movement, but suggest climate change could have been at play.

4-30-21 Arabian cult may have built 1000 monuments older than Stonehenge
A vast site in north-west Saudi Arabia is home to 1000 structures that date back more than 7000 years, making them older than the Egyptian pyramids and Stonehenge in the UK. Named after the Arabic word for rectangle, mustatil structures were first discovered in the 1970s, but received little attention from researchers at the time. Hugh Thomas at the University of Western Australia in Perth and his team wanted to learn more about them, and embarked on the largest investigation of the structures to date. Using helicopters to fly over north-west Saudi Arabia and then following up with ground explorations, the researchers found more than 1000 mustatils across 200,000 square kilometres – twice as many as were previously thought to exist in this area. “You don’t get a full understanding of the scale of the structures until you’re there,” says Thomas. Made from piled-up blocks of sandstone, some of which weighed more than 500 kilograms, mustatils ranged from 20 metres to more than 600 metres in length, but their walls stood only 1.2 metres high. “It’s not designed to keep anything in, but to demarcate the space that is clearly an area that needs to be isolated,” says Thomas. In a typical mustatil, long walls surround a central courtyard, with a distinctive rubble platform, or “head”, at one end and entryways at the opposite end. Some entrances were blocked by stones, suggesting they could have been decommissioned after use. Excavations at one mustatil showed that the centre of the head contained a chamber within which there were fragments of cattle horns and skulls. The cattle fragments may have been presented as offerings, suggesting mustatils may have been used for rituals. Radiocarbon dating of the skulls shows that they date to between 5300 and 5000 BC, indicating that this was when this particular mustatil was built – and maybe the others too. If so, the monuments would together form the earliest large-scale, ritual landscape anywhere in the world, predating Stonehenge by more than 2500 years.

4-30-21 Little Foot’s shoulders hint at how a human-chimp common ancestor climbed
The shape of the ancient hominid’s shoulder blades points to gorilla-like way of tree climbing. Little Foot, a nearly complete hominid skeleton painstakingly excavated from rock inside a South African cave, shouldered a powerful evolutionary load. This 3.67-million-year-old adult female sports the oldest and most complete set of shoulder blades and collarbones of any ancient hominid. Those fossils also provide the best available model for what the shoulders of the last common ancestor of humans and chimpanzees looked like, say Kristian Carlson, a paleoanthropologist at the University of Southern California in Los Angeles, and his colleagues. Their results provide new insights into how both Little Foot and a human-chimp last common ancestor climbed in trees. Little Foot belonged to the Australopithecus genus, but her species identity is in dispute (SN: 12/12/18). The shape and orientation of her shoulder bones fall between corresponding measures for humans and present-day African apes, but most closely align with gorillas, Carlson reported April 27 at the virtual annual meeting of the American Association of Physical Anthropologists. His talk was based on a paper published online April 20 in the Journal of Human Evolution. Little Foot lived roughly half-way between modern times and the estimated age of a human-chimp common ancestor, says paleobiologist David Green of Campbell University in Buies Creek, N.C., a member of Carlson’s team. If that ancient ancestral creature was about the size of a chimp, as many researchers suspect, shoulders resembling those of gorillas would have supported slow but competent climbing, Green says. Gorillas spend much of the time knuckle-walking on the ground. These apes climb trees with all four limbs, reaching up with powerful shoulders and arms to pull themselves along.

4-29-21 A baby’s first poo reveals if they are at risk of allergies and asthma
Children could be set on a path to developing allergies, asthma and eczema before they are born. Analysis of a baby’s first stool, known as meconium, shows that a lack of certain biochemicals and gut bacteria normally seen in the faeces is linked with a higher risk of allergies and other conditions. Allergic conditions such as food allergies, hay fever, asthma and eczema are caused by the immune system overreacting to harmless compounds in the environment. Many studies have found links between such immune system reactivity and a lower diversity of gut bacteria, or microbiome. One idea is that a diverse ecosystem of beneficial bacteria helps to “train” the developing immune system to tolerate non-harmful compounds. The new research, by Charisse Petersen at the University of British Columbia in Vancouver and her colleagues, analysed the meconium of 100 babies who had been part of a larger, ongoing Canadian study of child development. Meconium isn’t normal faeces, but a mixture of substances that entered the baby’s mouth in late pregnancy, such as amniotic fluid, skin cells and substances made by the baby’s skin. Chemically, it includes a range of fatty molecules, amino acids and other compounds from the mother’s diet. “Meconium is kind of a time capsule because it contains all of the molecules that the baby was exposed to,” says Petersen. Most allergic conditions develop in later childhood, so to get results when the infants were 1 year old, the team did a skin test that measures the reactivity of the immune system. The quarter of the group with the most chemically diverse meconium had half the risk of an overreactive immune system, compared with the quarter who had the least variable meconium. There was a similar-sized link between diverse gut bacteria in the meconium and later immune reactivity.

4-29-21 Japanese bay full of fish scales could mark start of the Anthropocene
A bay in south-west Japan could become the place on Earth that geologists use to officially establish the start of the Anthropocene, thanks to an abundance of sardine scales and other evidence revealing humanity’s growing influence on the planet. Beppu Bay this month formally joined 10 other sites being considered by researchers trying to find the planet’s best candidate for a “golden spike”, a clear signal in the Earth’s geological record that can designate a new epoch shaped by humanity’s impact. Scientists on the Anthropocene Working Group (AWG) voted in 2016 in favour of a defining new epoch starting around the middle of the 20th century, on the grounds humanity’s nuclear weapons testing, fossil fuel burning, plastic pollution and other activities were of sufficient scale to push the world into a new geological time. But the Anthropocene remains just an idea rather than an official epoch until its approval by the International Commission on Stratigraphy (ICS), the arbiter of geological timescales. Gaining approval will involve AWG researchers providing evidence from one location with enough markers to show the start of the Anthropocene. Radionuclides from nuclear weapons are thought to be the most obvious marker, but the AWG is seeking a location with multiple indicators to serve as the golden spike, or the global boundary stratotype section and point (GSSP). An ice core from Greenland marks the GSSP for the end of the Pleistocene and the Holocene, the current geological epoch. Now a flurry of research from Japan means Beppu Bay is the 11th potential GSSP, up against sites including a cave in Italy, a lake in China and a coral reef off Australia. “Beppu Bay is a spawning site for sardines in the western Pacific, and researchers have managed to match very nicely the density of sardine scales in the sediment core with written records of sardine catches in Japan over many centuries,” says Colin Waters at the University of Leicester, referring to a 2017 paper.

4-29-21 Billion-year-old microbe had taken first step towards internal organs
A tiny organism that lived a billion years ago had two different cell types, one forming its core and another its outer “skin”. It may have been one of the first life forms built that way, making it a crucial step towards modern organisms like animals that also have a skin that is distinct from the cells inside the body. “This fossil clearly is multicellular with two different types of cell,” says Charles Wellman at the University of Sheffield, UK. While organisms made of multiple cells were known to have existed for hundreds of millions of years, he says, having such an ancient one with recognisable cell types is new. The first organisms were single-celled – as many still are today – but, through the process of evolution, some began joining up to form larger multicellular organisms. “It’s actually surprisingly common,” says Emily Mitchell at the University of Cambridge. Multicellularity evolved independently several times in different groups. Eventually, some of these multicellular groups became large and complex organisms such as animals and plants. The oldest hard evidence of animals is from around 600 million years ago. Yet multicellular red algae have been reported from 1.6 billion years ago. There are even reports of multicellular organisms as early as 2.1 billion years ago. While not all these reports are convincing, says Mitchell, it seems clear that multicellular organisms remained simple for a long time. Wellman and his colleagues studied microfossils preserved in rocks in north-west Scotland. The rocks are about 1 billion years old and formed in an ancient freshwater lake. Within the rocks, there are fossil remains of a new species, which the researchers have named Bicellum brasieri. Each B. brasieri was a clump of a few dozen cells a few tens of micrometres across. There was a central ball of tightly packed oval cells, surrounded by an outer layer of sausage-shaped cells.

4-29-21 Billion-year-old fossil found preserved in Torridon rocks
A billion-year-old fossil found in the Highlands could be the earliest multicellular animal recorded by science so far. The microscopic fossil was discovered at Loch Torridon in Wester Ross by researchers led by the University of Sheffield and the US's Boston College. Scientists said it could prove a new link in the evolution of animals. Researchers could identify it contained two distinct cell types thanks to the fossil's "exceptional preservation". The fossil gives a new insight into the transition of single-celled organisms to complex multicellular animals. It has been named Bicellum Brasieri and is described in a new research paper published in Current Biology. Prof Charles Wellman, of the University of Sheffield, said: "The origins of complex multicellularity and the origin of animals are considered two of the most important events in the history of life on Earth, our discovery sheds new light on both of these. "We have found a primitive spherical organism made up of an arrangement of two distinct cell types, the first step towards a complex multicellular structure, something which has never been described before in the fossil record. "The discovery suggests that the evolution of multicellular animals occurred at least one billion years ago and that early events prior to the evolution of animals may have occurred in freshwater like lakes, rather than the ocean." The research team now hopes to examine other samples taken from the Torridon area's ancient rocks and find more fossils that could provide further insights into the evolution of multicellular organisms.

4-28-21 Why can’t humans regrow limbs like an axolotl or a lizard?
Why can’t humans regrow limbs like an axolotl or a lizard? Salamanders, such as axolotls, hatch in ponds alongside hungry siblings that nibble on them. This may explain why they evolved the ability to regenerate missing limbs and gills. In contrast, humans have a rolling programme of replacing about 10 billion cells per day. This hints at a possibility that we have inherited the ability to regenerate limbs, yet the relevant bits of genetic code may be switched off or modified. Rapid cell division is associated with tissue regeneration, but it is also a feature of cancer. It is possible that evolution in humans has suppressed rapid cell division in order to combat cancer at the cost of losing our ability to regenerate tissue. Tantalisingly, salamanders regenerate tissue but hardly ever get cancer. The axolotl is easy to breed in captivity, which has made it the focus of intensive research. When it loses a limb, cells migrate to the site of the wound, turning back their internal clocks on the way. The cells form a blastema, a mass of undifferentiated cells, like embryonic cells or stem cells. Immune cells called M2 macrophages reduce inflammation at the wound site, while connective tissue cells called fibroblasts carry positional information that allows them to differentiate into the appropriate specialised cells specific to their location as the lost limb regrows. Scientists have recently mapped the axolotl genome and this should speed up our genetic understanding of why some creatures can regenerate their limbs.

4-28-21 Allergies are on the rise – here's how to help scientists find out why
If you experience seasonal allergies, you can track your symptoms to help researchers investigate their environmental triggers, finds Layal Liverpool. APRIL showers bring May flowers, or so the saying goes. But those beautiful spring blooms – and their plentiful pollen – mean sneezing, runny noses and itchy eyes for many people. If this is you, and if you live in the UK, you can become a citizen sensor this spring by downloading the #BritainBreathing app and using it to record any allergy symptoms you develop. Doing so will help researchers learn more about when allergy symptoms are occurring at a population level and what the precise triggers are. Even if you don’t live in the UK, you can still download the app and use it for personal symptom tracking. About one in four people in the UK experience seasonal allergies, such as hay fever and asthma, and the incidence seems to be on the rise. The main culprit behind these ailments is pollen, with different types in the air at different times of year, but other factors such as the weather or levels of air pollution may also play a role. The #BritainBreathing app matches anonymised symptom information with a rough geographical location, so that researchers can get an idea of where allergy symptom reports are clustered across the UK. “That might start to tell us a little bit more about what’s in the environment that’s causing the huge increase in allergies and asthma that we’re seeing – because it’s going up and up,” says Sheena Cruickshank at the University of Manchester, UK, who is part of the #BritainBreathing team. Thousands of people have joined the project so far and a 2017 study found that symptom reports collected via the app mapped well onto areas with high levels of prescriptions for allergy treatments by doctors.

4-28-21 Multiple negative events before birth could lead to poor mental health
Children who experienced multiple negative events before birth, such as exposure to alcohol or pre-eclampsia, are at higher risk of experiencing poor mental health a decade later. Joshua Roffman at Harvard Medical School in Boston and his colleagues asked the parents of almost 10,000 children aged 9 or 10 years whether the children had experienced a range of negative events before birth. They also used a standard child behaviour questionnaire to identify children with mental health issues, including anxiety and depression. The negative events the researchers looked at included exposure to alcohol, tobacco or marijuana both before and after the pregnancy was known, pregnancy complications and birth complications. They also looked at unplanned pregnancies. These have all previously been identified as individual mental health risks to children, but the team found that they have a compounding effect – children that had experienced the most events were at highest risk. “The risk increased relatively steeply as the number of exposures went up, so while children who had no such exposures only had about a 7 per cent risk of clinically significant symptoms at that age, those with four or more exposures had a 29 per cent risk,” says Roffman. This could help identify families and children who may need more support, says Helen Dodd at the University of Reading, UK. “Some of it is about supporting women who are pregnant to prevent big exposures and some of it is also about using these exposures as ways of working out who might need the most support during those early years.” The researchers used data collected through interviews and surveys to control for early childhood trauma and environmental variables including post-birth parental conflict and neighbourhood safety.

4-28-21 'Smart' immune cells kill tumours and stop them regrowing in mice
Immune cells programmed to attack tumours in a smarter way have shrunk brain, skin and ovarian tumours in mice studies where unaltered immune cells failed. The technology could be used to treat cancers as well as degenerative brain disorders. “We have more control over what the cell does when it reaches the disease site,” says Kole Roybal at the University of California, San Francisco. “We can really program in very specific functions.” Our bodies naturally kill off many nascent cancers, but sometimes immune cells called T-cells don’t recognise cancerous cells. One way to treat cancers that manage to dodge the immune system is to genetically engineer T-cells to produce a receptor that helps them target a specific protein on the cancer cell’s surface. These are called CAR T-cells, where CAR stands for chimeric antigen receptor. CAR-T therapies have cured a few people, leading the US to approve two forms in 2017. But there are major limitations. The approach has only been effective against blood cancers such as leukaemia, not against solid tumours. And it can have very serious – even fatal – side effects if the T-cells kill off non-cancerous cells that also have the target protein on their surface. These problems are related. One of the reasons why CAR-T therapies don’t work for solid tumours is that not all cells in such tumours express a single, unique protein, says Roybal. So his team has developed a new type of receptor protein that works in a different way. Instead of triggering an instant attack, these T-cell receptors switch on any desired gene or genes when they recognise a target protein, which can be any protein the researchers choose. Roybal’s team engineered this receptor to recognise a protein specific to some cells in brain tumours called glioblastomas. The receptor then activated a gene for a standard CAR-T receptor that targets a protein found on a wider range of tumour cells and on healthy cells. Crucially, though, the killing effect was limited to tumour environments where both proteins are present: if the engineered cells leave the tumour, the CAR-T gene gets switched off again.

4-28-21 Covid-19 lockdown has left young children vulnerable to some illnesses
THE coronavirus pandemic has left children vulnerable to other infections, in part due to reduced interactions as a result of lockdowns and social distancing. In Australia, which has largely been covid-free for the past six months, there has been a delayed surge in cases of respiratory syncytial virus (RSV), a common, flu-like illness that causes a lung infection called bronchiolitis and often has the most serious effects in children under the age of 2. RSV infections typically peak in winter, but in 2020, the RSV season in Australia was curtailed by covid-19 stay-at-home orders and public health measures. In Western Australia, a recent analysis of hospital presentations shows that RSV cases dropped by 98 per cent during the winter months of 2020 compared with the same period in previous years, but began to surge in spring, in late September, eventually exceeding the median seasonal peak from 2012 to 2019 (Clinical Infectious Diseases, doi.org/f8s5). Daniel Yeoh, an infectious diseases clinician at Perth Children’s Hospital who co-authored the analysis, estimates that the proportion of children in hospital who tested positive for RSV jumped from less than 1 per cent in April 2020 to 70 per cent in the summer months. Other Australian states have seen similar trends, most recently Victoria, which only recently relaxed mask-wearing rules. “You’ve got a larger group of children who’ve never seen RSV before in their life, 18 months and below, and then older children who may have seen RSV 18 months ago but their immunity from that particular encounter with RSV might have waned,” says Yeoh. As northern hemisphere countries ease their lockdowns, there is a risk they could also see surges in RSV, he says.

4-28-21 We'll soon be able to tell whether you are immune to covid-19
WE ARE getting closer to answering one of the most important remaining questions in the pandemic: how can we quickly test whether somebody is immune to the virus? This elusive measurement of immunity is known as the correlate of protection: a simple, surrogate appraisal of the entire immune response that tells you whether somebody is protected against disease or infection. “So, for example, you measure the number of antibodies in blood and find that if you have a specific number you are protected,” says Christine Dahlke at the University Medical Centre Hamburg-Eppendorf in Germany. That number is a correlate of protection, or CoP. We don’t yet have one for SARS-CoV-2, says Dahlke, but we urgently need one. CoPs are a standard tool in vaccinology and, although difficult to nail down, we have established them for numerous conditions, including measles, influenza and hepatitis. Getting one for covid-19 would be a boost to our efforts to end the pandemic, says Dahlke. It would allow us to bypass big vaccine trials that compare a vaccine candidate against a placebo to see the difference in infection rates. Instead, we could do simpler and quicker tests that identify whether a vaccine elicits the CoP. Finding a CoP for SARS-CoV-2 is a pressing issue because, despite the unprecedented success in developing covid-19 vaccines through large-scale clinical trials, there are growing fears that this approach has run its course. As the pandemic progresses, such trials become increasingly difficult to perform, for two reasons. First, finding volunteers who haven’t been vaccinated or infected and so are immunologically naive is hard. Second, giving unprotected people placebos when good vaccines exist is unethical. “We need a better approach,” says Dahlke.

4-27-21 Science with Sam: Why can’t we stay awake indefinitely?
We spend one-third of our lives asleep, but why is it so essential? In this episode, we explain the science of sleep and why we can’t stay awake indefinitely. For something we spend so much time doing, we still don’t really know what sleep is for. It’s clear that we need it. Our ability to perform tasks and make decisions is greatly impaired by a lack of sleep, as anyone who has had a restless night will attest. But it’s not just humans who are so reliant upon shut-eye. Animals need sleep too, even birds that fly continuously for months. So what’s sleep for? And why can’t we stay awake indefinitely? In this episode of Science with Sam, the first in the new series, we explain the science of sleep. We spend about a third of our lives asleep. And if we miss out on it, we get physically sick. Clearly sleep is extremely important, but why? What’s going on in our brains while we’re out of it? Why can’t we stay awake all the time? And how can we make sure we’re getting enough? It’s not just us humans who need our shuteye. Bees need about as much sleep as we do. If you keep them up at night, they are badly affected. This is a normal bee doing the waggle dance, a sort of insect version of charades that tells other bees where to find food. And here’s a sleep-deprived bee. Its moves are less precise; there is more variation in the angle of its dance, and as a result, it’s giving bad directions. If you miss a night’s sleep and then try to dance, or play charades, you’ll be like this too. Even animals that spend weeks or months flying continuously can’t do without sleep. Researchers have put wearable brainwave recorders on great frigatebirds to confirm the common belief that birds can sleep while flying. They napped in short bursts of about 12 seconds during long flights, getting a total of 41 minutes per day, usually sleeping one half of the brain at a time. When they were back on land, they would sleep for more than 12 hours a day.

4-27-21 COVID-19 can affect the brain. New clues hint at how
Researchers are sifting through symptoms to figure out what the virus does to the brain. For more than a year now, scientists have been racing to understand how the mysterious new virus that causes COVID-19 damages not only our bodies, but also our brains. Early in the pandemic, some infected people noticed a curious symptom: the loss of smell. Reports of other brain-related symptoms followed: headaches, confusion, hallucinations and delirium. Some infections were accompanied by depression, anxiety and sleep problems. Recent studies suggest that leaky blood vessels and inflammation are somehow involved in these symptoms. But many basic questions remain unanswered about the virus, which has infected more than 145 million people worldwide. Researchers are still trying to figure out how many people experience these psychiatric or neurological problems, who is most at risk, and how long such symptoms might last. And details remain unclear about how the pandemic-causing virus, called SARS-CoV-2, exerts its effects. “We still haven’t established what this virus does in the brain,” says Elyse Singer, a neurologist at the University of California, Los Angeles. There are probably many answers, she says. “It’s going to take us years to tease this apart.” For now, some scientists are focusing on the basics, including how many people experience these sorts of brain-related problems after COVID-19. A recent study of electronic health records reported an alarming answer: In the six months after an infection, one in three people had experienced a psychiatric or neurological diagnosis. That result, published April 6 in Lancet Psychiatry, came from the health records of more than 236,000 COVID-19 survivors. Researchers counted diagnoses of 14 disorders, ranging from mental illnesses such as anxiety or depression to neurological events such as strokes or brain bleeds, in the six months after COVID-19 infection.

4-27-21 One in four people in England exercised less during and after lockdown
More than one in four people in England did less exercise than normal after the first lockdown, and didn’t increase it afterwards. The results from the first study of how physical activity changed beyond lockdown suggests that decreased physical activity could worsen obesity levels in the country. Efforts were made to encourage exercise during the first lockdown, which took place between March and May 2020. Fitness coach Joe Wicks’ delivered daily P.E lessons for the whole family, while gyms quickly started offering zoom classes. However, a survey of 36,000 people taking part in the University College London Covid-19 Social Study found that 29 per cent decreased their physical activity between March and August last year. “It’s a sizeable number,” says Andrew Steptoe at UCL. “[Although] there were stay at home orders, people were encouraged to go out and exercise – but some people didn’t. Some people were frightened of catching covid. Some didn’t live in the circumstances where they had the opportunity to do this.” Steptoe adds he was surprised that people were not more active after restrictions lifted in May. The research, which has not yet been peer-reviewed, found 62 per cent of people maintained their old level of physical activity, and just 9 per cent increased it. Steptoe and colleagues had expected there might be an urban-rural divide, with people outside of towns and cities having more space and therefore exercising more, but that was not the case. Gender and ethnicity also did not seem to make a difference to how active people were. However, those who were older, more educated, richer and lived with other people were more likely to be more active. “One of the things I was quite struck by was older people were [more] active compared to young adults aged 18 to 29, which is unusual,” says Steptoe. He suspects that may be partly due to younger people being more reliant on organised sports, which were limited by restrictions, with older people more often walking or jogging on their own. “That social component might be important,” he says.

4-26-21 A single pint of beer contains up to 2 million bubbles
When beer is poured into a 500-millimetre glass, somewhere between 200,000 and 2 million bubbles rise to the surface to form the foamy head. This estimate was made by Ge´rard Liger-Belair and Clara Cilindre at the University of Reims Champagne-Ardenne in France, who calculated the number of tiny bubbles that form before a lager goes flat. The researchers first measured the amount of carbon dioxide dissolved in 250 millilitres of lager after it was poured into a tilted glass. They then calculated the number of bubbles that would form, assuming the lager was at 6°C – its recommended drinking temperature. The total number is dependent on the type of glass that is used. Bubbles form where microscopic crevices and cavities in the inside wall of the glass are more than 1.4 micrometres wide. The researchers included estimates for glasses with different sizes of microscopic crevices – between 1 micrometre and 10 micrometres in size – resulting in the large range of total possible bubbles in a glass of beer. “If your glass is perfectly smooth on the inside, thermodynamically speaking, it will not be able to produce any bubbles,” says Liger-Belair. “The size and amount of these bubbles is dependent on these tiny imperfections in the glass.” The more imperfections on the surface of the glass, the more bubbles form. The number and size of the bubbles is also dependent on the height of the glass – taller glasses form larger bubbles. “This is because the bubbles grow in size as they rise to the liquid’s surface,” says Liger-Belair. That is why beer is often poured into a tilted glass: creating a smaller distance for bubbles to travel leads to less foam. Liger-Belair and Cilindre’s previous research found that a typical bubble in beer is about half a millimetre in diameter once it reaches the head. For comparison, bubbles in champagne are typically about 1 millimetre wide. But when they first form, beer bubbles can be around 10 micrometres in diameter, says Javier Rodríguez Rodríguez at University Carlos III of Madrid in Spain, who wasn’t involved in the research.

4-23-21 Can we finally wipe out malaria with a vaccine 37 years in the making?
Efforts to make malaria history have had huge success in recent years. Now, there’s hope that a long-awaited vaccine can go the last mile “We longed for it to come,” Janet Mula told me, recalling her reaction to hearing that scientists were developing a vaccine against malaria. Mula, a nurse I met while travelling in rural Kenya, has seen the devastation caused by this disease first-hand. Each year, it sickens more than 200 million people globally, killing at least 400,000. The vast majority of cases are in sub-Saharan Africa, with the biggest burden falling on younger people. “Malaria causes many complications for children – anaemia, organ failure, jaundice, liver complication,” says Mula. That could soon change, however. While most of the world is focusing on new vaccines for the coronavirus, thousands of Kenyan children are finally receiving a longed-for malaria vaccine, 37 years after development on it started. Since 2019, Kenya, Ghana and Malawi have been taking part in a pilot programme coordinated by the World Health Organization (WHO). If it is successful, the vaccine will be rolled out to infants across Africa. As this went to press, trial results of another vaccine developed by the University of Oxford suggested it was 77 per cent effective. Some hope these vaccines will eventually help to eradicate malaria entirely. Every year on 25 April, World Malaria Day, the WHO assesses the progress made in combating the disease – and it has been considerable. But eradication would be a massive achievement: it has only ever happened with one human disease, smallpox. “Eradicating smallpox – it’s a wonderful story,” says global public health consultant Desmond Chavasse. “But we so nearly failed. The world nearly lost its determination to do it.” When it comes to malaria, even with a new vaccine, if action isn’t fast, we may miss our chance.

4-23-21 Glancing at your phone quickly prompts other people to do the same
When a person looks at their mobile phone, around half the people nearby will start checking their phones within 30 seconds. Such a rapid, automatic response is probably due to people mimicking each other without realising it – what scientists call the “chameleon effect”. While such mimicry is thought to have evolved in human societies to help people bond with each other, mimicking mobile phone use might have the opposite effect, says Elisabetta Palagi at the University of Pisa, Italy. “We have a need to follow the norms imposed on us by people around us, to [match] our actions with theirs in this automatic way,” she says. “But smartphones can increase social isolation through interference and disruption with real-life, ongoing activities.” Worse, people without phones can’t even try to replicate the behaviour. “So these people can feel especially isolated.” Palagi had already investigated the chameleon effect in humans – which can include facial expressions, hand movements, foot shaking, yawning and speech patterns. So when her student Veronica Maglieri noted how people – including herself – always seemed to pick up their phones when other people did, they decided to run an observational study. The team watched 88 women and 96 men in 820 different situations in natural settings – parks, restaurants, public transportation, waiting rooms and dinner parties, for example – to see how many would look at their phones after someone else nearby did. These “trigger” individuals pushed buttons or swiped their screens for five seconds, either with or without looking at the lit-up screen. The researchers found that 50 per cent of people looked at their phone within 30 seconds of the trigger touching and looking at his or her phone, but just 0.5 per cent of people did so when the trigger touched the phone without looking at it. “It’s paying attention to the phone that sets off the mimicry,” Palagi says.

4-23-21 Malaria vaccine from Oxford covid-19 team is most effective ever made
A malaria vaccine shown to be 77 per cent effective in trials – the highest level ever achieved – offers hope of controlling a disease that kills an estimated 400,000 people each year, many of them children. Adrian Hill at the University of Oxford and his colleagues hope it can be approved for use within the next two years, building on the speed and lessons learned through the rapid development of covid-19 vaccines – the researchers also work on the Oxford/AstraZeneca coronavirus vaccine. “With the commitment by our commercial partner, the Serum Institute of India, to manufacture at least 200 million doses annually in the coming years, the vaccine has the potential to have a major public health impact if licensure is achieved,” he told the PA news agency. Hill hopes the vaccine will be swiftly approved following final trial results, which he expects the team to report next year. “Malaria killed at least four times as many more people in Africa last year as covid did,” he said. “Nobody for a moment questioned whether covid should have an emergency use review and authorisation in Africa – of course it did, very quickly. So why shouldn’t a disease that firstly kills children rather than older people, certainly killed an awful lot more, be prioritised for emergency use authorisation in Africa?” The first scientific report for a malaria vaccine was published in 1910, the first trial of a malaria vaccine took place in the 1940s, and 140 malaria vaccines have gone into clinical testing. Hill said there had been no shortage of effort, but it had just been incredibly difficult. “I’ve been working on malaria vaccines since 1994 – it is not 111 years but sometimes it feels a bit like that,” he said. The World Health Organization (WHO) has set a target of 75 per cent efficacy by 2030 for a malaria vaccine, and the new vaccine is the first to achieve that level. “This is great, fantastic. We saw the first look at these results after six months last year and we were, we were thrilled,” said Hill.

4-23-21 Malaria vaccine hailed as potential breakthrough
A malaria vaccine has proved to be 77% effective in early trials and could be a major breakthrough against the disease, says the University of Oxford team behind it. Malaria kills more than 400,000 people a year, mostly children in sub-Saharan Africa. But despite many vaccines being trialled over the years, this is the first to meet the required target. The researchers say this vaccine could have a major public health impact. When trialled in 450 children in Burkina Faso, the vaccine was found to be safe, and showed "high-level efficacy" over 12 months of follow-up. Larger trials in nearly 5,000 children between the ages of five months and three years will now be carried out across four African countries to confirm the findings. Malaria is a life-threatening disease caused by parasites that are transmitted to people through mosquito bites. Although preventable and curable, the World Health Organization estimates there were 229 million cases worldwide in 2019 and 409,000 deaths. The illness starts with symptoms such as fever, headaches and chills and, without treatment, can progress quickly to severe illness and often death. Study author Adrian Hill, director of the Jenner Institute and professor of vaccinology at the University of Oxford, said he believed the vaccine was the first to reach the World Health Organization's goal of at least 75% efficacy. The most effective malaria vaccine to date had only shown 55% efficacy in trials on African children. The trials of this malaria vaccine started in 2019, long before coronavirus appeared - and the Oxford team developed its Covid vaccine (with AstraZeneca) on the strength of its research into malaria, Prof Hill said. A malaria vaccine has taken much longer to come to fruition because there are thousands of genes in malaria compared to around a dozen in coronavirus, and a very high immune response is needed to fight off the disease.

4-23-21 Early Europeans shared a currency made from odd chunks of bronze
The first pan-European currency may have existed more than 2800 years ago in the Bronze Age. There were no coins yet and no central bank, but people across Europe used fragments of bronze – the majority of which were either a standard mass or a multiple of that. “You can actually think of some monetary union in Europe without public institutions,” says Nicola Ialongo at the University of Göttingen in Germany. Bronze is an alloy of copper and other metals, usually tin, that was used widely in Europe from about 2300 BC to 800 BC – hence the term Bronze Age. This widespread access to those metals must have involved trade. For one thing, “copper is not very common”, says Ialongo. It was mined at several sites including in the Eastern Alps. A new study shows that it was also being smelted in what is now eastern Serbia between 2000 and 1500 BC, more than 500 years earlier than thought. Tin is even harder to find: Ialongo describes it as “incredibly rare”. It was extracted in what is now Cornwall in the south-west of England, and there were also sites in eastern Europe and Turkey, says Ialongo. “It’s really difficult to get access to tin and yet it was everywhere.” This continent-spanning trade was the ideal situation for a unified form of money to arise, he says. This was made possible by the spread of weighing technology such as balance scales, which were invented around 3000 BC between Mesopotamia and Egypt and subsequently spread throughout Europe. The weights were often made of stone and the balance beam of bone or antler. Weighing scales meant people could determine the value of a commodity in a more objective way. Ialongo and his colleague Giancarlo Lago of Sapienza University of Rome in Italy, studied more than 3000 fragments of bronze from Bronze Age sites scattered around Europe. The fragments had been broken off larger objects, potentially from things like such as axe heads.

4-22-21 A new technique could make some plastic trash compostable at home
Embedding enzymes in the material causes it to rapidly break down without creating microplastics. A pinch of polymer-munching enzymes could make biodegradable plastic packaging and forks truly compostable. With moderate heat, enzyme-laced films of the plastic disintegrated in standard compost or plain tap water within days to weeks, Ting Xu and her colleagues report April 21 in Nature. “Biodegradability does not equal compostability,” says Xu, a polymer scientist at the University of California, Berkeley and Lawrence Berkeley National Laboratory. She often finds bits of biodegradable plastic in the compost she picks up for her parents’ garden. Most biodegradable plastics go to landfills, where the conditions aren’t right for them to break down, so they degrade no faster than normal plastics. Embedding polymer-chomping enzymes in biodegradable plastic should accelerate decomposition. But that process often inadvertently forms potentially harmful microplastics, which are showing up in ecosystems across the globe (SN: 11/20/20). The enzymes clump together and randomly snip plastics’ molecular chains, leading to an incomplete breakdown. “It’s worse than if you don’t degrade them in the first place,” Xu says. Her team added individual enzymes into two biodegradable plastics, including polylactic acid, commonly used in food packaging. They inserted the enzymes along with another ingredient, a degradable additive Xu previously developed, which ensured the enzymes didn’t clump together and didn’t fall apart. The solitary enzymes grabbed the ends of the plastics’ molecular chains and ate as though they were slurping spaghetti, severing every chain link and preventing microplastic formation. Adding enzymes usually makes plastic expensive and compromises its properties. However, Xu’s enzymes make up as little as 0.02 percent of the plastic’s weight, and her plastics are as strong and flexible as one typically used in grocery bags.

4-22-21 Capturing the sense of touch could upgrade prosthetics and our digital lives
Haptics researchers are working on ways to add touch to virtual reality, online shopping, telemedicine and advanced artificial limbs. On most mornings, Jeremy D. Brown eats an avocado. But first, he gives it a little squeeze. A ripe avocado will yield to that pressure, but not too much. Brown also gauges the fruit’s weight in his hand and feels the waxy skin, with its bumps and ridges. “I can’t imagine not having the sense of touch to be able to do something as simple as judging the ripeness of that avocado,” says Brown, a mechanical engineer who studies haptic feedback — how information is gained or transmitted through touch — at Johns Hopkins University. Many of us have thought about touch more than usual during the COVID-19 pandemic. Hugs and high fives rarely happen outside of the immediate household these days. A surge in online shopping has meant fewer chances to touch things before buying. And many people have skipped travel, such as visits to the beach where they might sift sand through their fingers. A lot goes into each of those actions. “Anytime we touch anything, our perceptual experience is the product of the activity of thousands of nerve fibers and millions of neurons in the brain,” says neuroscientist Sliman Bensmaia of the University of Chicago. The body’s natural sense of touch is remarkably complex. Nerve receptors detect cues about pressure, shape, motion, texture, temperature and more. Those cues cause patterns of neural activity, which the central nervous system interprets so we can tell if something is smooth or rough, wet or dry, moving or still. Neuroscience is at the heart of research on touch. Yet mechanical engineers like Brown and others, along with experts in math and materials science, are studying touch with an eye toward translating the science into helpful applications. Researchers hope their work will lead to new and improved technologies that mimic tactile sensations.

4-22-21 X-ray scans explain how the ‘Brazil nut effect’ works
Videos reveal larger particles flip vertically, letting smaller ones fall below. A new experiment reveals, in a nutshell, why the largest particles in some mixtures tend to gather at the top. This phenomenon is known as the Brazil nut effect, since jostling mixed nut packages tends to bring bulky Brazil nuts to the top. The effect can also be seen in cereal boxes and even space rocks (SN: 8/15/14). Understanding how it works could help manufacturers create more uniform mixtures of ingredients for food processing, or more even distributions of active ingredients in medicine tablets, researchers report April 19 in Scientific Reports. The Brazil nut effect has been tough to crack because it’s difficult to track how individual objects move around in the middle of a mixture, says Parmesh Gajjar, an imaging scientist at the University of Manchester in England. Using X-ray CT scans, Gajjar and colleagues followed the motion of individual peanuts and Brazil nuts in a box as it was shaken back and forth — creating the first 3-D videos of the Brazil nut effect in action. In the videos, the Brazil nuts, which are oblong, mostly laid horizontally when they were first dumped into the container. But as the box shook, collisions between nuts nudged some of the Brazil nuts to point more vertically. That vertical orientation opened up space for the smaller peanuts higher in the mixture to tumble down and accumulate at the bottom, pushing the Brazil nuts upward. While this finding could satisfy the curiosity of mixed nut aficionados, that’s peanuts compared to the practical use it could have for the pharmaceutical industry.

4-21-21 How has the covid-19 pandemic affected STEM pay and job prospects?
The covid-19 pandemic has been a bumpy ride for many sectors, but a New Scientist Jobs/SRG survey shows that science and tech have weathered the storm better than most. SINCE the beginning of the covid-19 pandemic well over a year ago, industries and businesses across the board have been forced to change working practices and business models in a period of unprecedented global economic uncertainty. How has it affected those working in science, technology, engineering and mathematics (STEM)? That was a key question in this year’s New Scientist Jobs STEM industry survey, conducted in association with science recruitment specialists SRG. And there is good news: despite the economic setback, science industries and their employees haven’t been as hard hit as might be expected, although the future remains uncertain. More than 2400 people from across industry and academia in Europe and North America took part in the survey. It found that despite covid-19 uncertainties, salaries for STEM jobs in the UK and North America have increased on average from the previous year, while earnings for the rest of Europe excluding the UK are largely unchanged. The majority of STEM employees feel satisfied in their jobs and are optimistic for the coming year. That said, the pandemic has hindered some people’s job plans and prospects. Some employees, for example, were unable to work as a result of their company having to close or operate at reduced capacity. It is no surprise either that covid-19 was seen by survey respondents as their biggest concern over the next 12 months, mentioned by around 40 per cent in all geographical areas covered by the survey. That was also true across a range of different sectors, including pharmaceutical, biotechnology and academia. Lockdowns and other restrictive measures have had a clear and dramatic effect on productivity in the wider economy. According to the UK Office for National Statistics (ONS), economic activity in the country had fallen 30 per cent compared with pre-pandemic levels by May 2020, around two months into the first nationwide lockdown. More than 7 million jobs were considered to be at risk. Dramatic reductions in economic output were also recorded in Europe and the US.

4-21-21 The science of how lockdown messes with the way we grieve
Lockdown is affecting how millions of people grieve. We need to be mindful of that when restrictions ease, says Dean Burnett. A YEAR ago, my 58-year-old otherwise healthy father contracted covid-19. He eventually succumbed to it, and died. And I have been dealing with the grief ever since, while under lockdown. If you go by how it is portrayed in mainstream fiction, grief is very predictable. You go through five stages: denial, anger, bargaining, depression and acceptance. Once through all these stages, you can move on with your life. But reality is far more complex. Elisabeth Kübler-Ross, who came up with the five-stage idea, regretted writing it in such a way that led to its simplistic portrayal. The stages reflect the sort of reactions people can have, but they don’t form a rigid road map. Grief during lockdown is even more complex. I say this as someone who, like millions of other people, has endured months of it, cut off from friends and family. I fear this is causing genuine problems that are going unrecognised or unacknowledged. Neurologically, emotions are a complex and unpredictable mess. The brain areas involved are intertwined with practically every other neurological function. This is why emotional experiences can affect us so potently and take so long to process. Our brains learn and develop based on our experiences and understanding of the world around us. So, even if inaccurate or oversimplified, the cultural consensus about grief informs our expectations. We “know” that when you lose someone, you have a funeral and wake to say goodbye to or celebrate the departed. These accepted parts of the grieving process are thrown out of whack by lockdown. And while well intentioned, socially distanced funerals may do more harm than good. Among other things, rituals give the bereaved a sense of control over events, something important for well-being, and something that, at present, is drastically reduced following the loss of a loved one.

4-21-21 Exercise pills: They seem to work but how should we use them?
Researchers have developed drugs that bestow many of the health benefits of working out. In the process, they might have figured out how to treat currently untreatable diseases like Alzheimer’s. RONALD EVANS never intended to kick off a performance-enhancing drug craze, but that is what happened. Despite a ban on its use in sports, the substance he has long been studying has now been detected in doping tests of cyclists and boxers, while runners and bodybuilders share stories online about how it makes them leaner and stronger nonetheless. The story begins in 2002, when Evans, a biologist at the Salk Institute in La Jolla, California, performed some experiments involving mice and exercise wheels. He fed a drug known as GW1516 to unfit mice, expecting to see modest effects on their fat metabolism. But tests showed that mice which had been given the drug could run twice as far on their wheels as ones that hadn’t. “It was an amazing moment,” says Evans. Couch-potato mice had been transformed into endurance runners. Ever since, he has been chasing a dream with ramifications not just for elite athletes, but all of us. We know that exercise truly is the best medicine. Get your body moving, even a modest amount, and the rewards range from stronger bones to a sharper mind. But what if you could use a pill to mimic those benefits without having to do any training at all? That question – and Evans’s promising work – have sparked a drug-discovery movement. As the first fruits of this work edge closer to the clinic, there is an increasingly heated debate about how these kinds of therapies should be used. All agree, however, that a healthcare revolution is on the way. Many of us turn to exercise as a means of losing weight, but the benefits go way beyond that. Working out challenges virtually every organ in the body, stimulating growth and repair. It also causes a broad shift in the body’s metabolism that protects against obesity, metabolic disorders such as diabetes, and cancer. Other upsides include a more efficient cardiovascular system, boosted cognition, memory and mood, and even a longer life.

4-21-21 We shouldn't use Renaissance watermelons to judge nutritional value
Many crops have changed over the years through cultivation, but that doesn't mean they have become less nutritious nor is that possible to judge from a picture, writes James Wong. NOW, I realise my lifelong fascination with how the crops that sustain humanity today were domesticated in the ancient past isn’t shared by everyone. So I was excited to see some classic examples of before and after pictures of familiar fruit and veg popping up on my Twitter feed a few years ago. These showed the sometimes stark differences between the supermarket staples that are familiar today with the wild relatives they were originally derived from. Imagine my surprise when these photographs – normally confined to ethnobotanical textbooks – started to appear on other social media platforms, then blogs and eventually newspapers, used to support a claim that today’s crops are inherently lower in nutrition, and even dangerous to our health. According to this argument, today’s crops – from carrots to bananas – have been altered so far beyond their natural state that they are now essentially bags of sugar, with a similar effect on our bodies. These images are enough to emphatically demonstrate this, according to proponents. But is a plant’s appearance a reliable guide to its nutritional value over the centuries? Let’s walk through the evidence together. Perhaps the most striking visual used to illustrate this claim is that of an Italian Renaissance painting containing a watermelon by Giovanni Stanchi. With swirls of white in its light pink flesh, it does look rather different to the typical bright crimson varieties popular today. Yet, the reality is that even today, watermelons come in many colours, from canary yellow to the palest white, many of us are just most familiar with the red kind.

4-21-21 Tyrannosaurs may have hunted together in packs like wolves
Seventy-four million years ago, tyrannosaurs hunted in the jungles of the late Cretaceous period – but they weren’t alone. Fossils from a family of drowned tyrannosaurs suggest these giants formed cohesive groups that hunted in packs. The fossils come from a site at Grand Staircase-Escalante National Monument in southern Utah. In 2014, Alan Titus at the US Bureau of Land Management stumbled upon the remains of a group of tyrannosaurs. “The first discovery bone was an ankle bone, and within minutes of brushing around, we uncovered dozens of other tyrannosaur bones,” he said in a press conference. In total, five tyrannosaur skeletons of the genus Teratophoneus were unearthed. Based on their sizes, the team estimated that the group is composed of one adult, one subadult and three juveniles. Celina Suarez at the University of Arkansas performed a stable isotope analysis on samples taken from each of the skeletons to determine the environment these dinosaurs lived in, how they were fossilised and the potential cause of death. She found that they died together in a single catastrophic event – a flood. The tyrannosaur family died and was fossilised at the same time, which provides more evidence that these dinosaurs were gregarious animals that lived and hunted in groups, much like wolves do today. Group hunting by large predators like tyrannosaurs is rare. “Predators don’t instinctively become gregarious as easily as plant eaters,” says Titus. Notable exceptions such as wolves, orcas and lions come to mind, but most hunters hunt alone. Despite the Utah discovery, evidence of social behaviour among tyrannosaurs remains rare. Trackways of multiple Tyrannosaurus rex in one location suggest that they may have hunted together. Evidence of group life also comes from a site in Canada hypothesised to be the location of a mass death of tyrannosaurs.

4-20-21 Videocalling needed more than a pandemic to finally take off. Will it last?
Eileen Donovan, an 89-year-old mother of seven living in a Boston suburb, loved watching her daughter teach class on Zoom during the coronavirus pandemic. She never imagined Zoom would be how her family eventually attended her funeral. Donovan died of Parkinson’s disease on June 30, 2020, leaving behind her children, 10 grandchildren and six great-grandchildren. She always wanted a raucous Irish wake. But only five of her children plus some local family could be there in person, and no extended family or friends, due to coronavirus concerns. This was not the way they had expected to mourn. For online attendees, the ceremony didn’t end with hugs or handshakes. It ended with a click on a red “leave meeting” button, appropriately named for business meetings, but not much else. It’s the same button that Eileen Donovan-Kranz, Donovan’s daughter, clicks when she finishes an English lecture for her class of undergraduate students at Boston College. And it’s the same way she and I ended our conversation on an unseasonably warm November day: Donovan-Kranz sitting in front of a window in her dining room in Ayer, Mass., and me in my bedroom in Manhattan. “I’m not going to hold the phone during my mother’s burial,” she remembers thinking. Just a little over a year ago, it would have seemed absurd to have to ask someone to hold up a smartphone so that others could “attend” such a personal event. Donovan-Kranz asked her daughter’s fiancé to do it. The COVID-19 pandemic has profoundly changed the way people interact with each other and with technology. Screens were for reminiscing over cherished memories, like watching VHS tapes or, more recently, YouTube videos of weddings and birthdays that have already happened. But now, we’re not just watching memories. We’re creating them on screens in real time.

4-20-21 Reporting of US police killings harms Black people's mental health
Black people are more likely than white people to have their mental health affected by strings of highly publicised US police killings of Black people, according to the first nationwide scientific assessment of these media reports. Police violence against Black people in the US often leads to extensive media coverage. David Curtis at the University of Utah and his colleagues wanted to understand how the mental health of Black individuals was affected after such events. The team combined a database of US police killings with Google Trends data to identify 47 high-profile incidents of police killing Black individuals or subsequent legal decisions that occurred between 2013 and 2017, including the killing of Michael Brown. These comprised the reporting of 38 police killings of Black individuals, and coverage of about nine legal decisions not to convict officers involved in some of those killings. The team also looked at the reporting of two convicted murderers with links to white supremacy for a total of 49 events. The researchers assessed the mental health impacts on people during this time period using weekly data from the Behavioural Risk Factor Surveillance System survey, a large-scale health-related telephone survey funded by the US Centers for Disease Control and Prevention. On average, this included 696 responses a week from Black people and 6707 from white people – more than 200,000 Black individuals and 2 million white respondents in total between 2012 and 2017. The survey asks respondents whether they experienced poor mental health days in the past month, including those related to stress, depression and problems with emotions. Black respondents reported more poor mental health days during weeks when two or more of the selected events occurred in the country. Conversely, white respondents’ mental health wasn’t correlated to the timing of the events.

4-20-21 50 years ago, scientists claimed marijuana threatened teens’ mental health
Excerpt from the April 24, 1971 issue of Science News. The White House Conference on Youth voted to legalize the sale of grass (with restrictions). On the same day, the Journal of the American Medical Association published an article condemning the use of marijuana by the young.… The researchers conclude that marijuana smoking is particularly harmful to the adolescent. It adds unnecessary anxieties to the already disturbing problems of physical and psychological maturation. Fifty years after the recommendation to legalize the recreational use of marijuana, at least 15 U.S. states have done so. In that time, a growing body of research has strengthened the link between teen marijuana use and mental health effects, including an increased risk of depression later in life. Such health concerns partly explain why people younger than 21 are prohibited from recreationally using pot. But pot use is prevalent among U.S. middle and high school students: About 25 percent of students in grades 8, 10 and 12 disclosed using the drug in 2020, scientists report.

4-20-21 New species of dinosaur unearthed in Chile's Atacama desert
Scientists have identified a new species of dinosaur from parts of a skeleton found in northern Chile. The creature's remains were unearthed in the Atacama desert - the world's driest - near the city of Copiapó. Experts say the plant-eating titanosaur had a small head and long neck, and an unusually flat back. Studies suggest the creature lived in what would then have been a lush landscape of flowering plants, ferns and palm trees. A team led by Chilean geologist Carlos Arévalo unearthed the remains in the 1990s and carried out research in the 2000s. The findings, published in the journal Cretaceous Research, were made public on Monday. The remains, according to the team, included parts of a humerus, a femur and the ischium, and vertebral elements of the neck and back. They represent a small sub-adult individual, with an estimated length of 6.3m (20ft). The creature was a sauropod, or a long-necked, long-tailed, plant-eating dinosaur. It was found in beds dating from the Late Cretaceous, the last epoch before dinosaurs were wiped out 66 million years ago. The creature has been named Arackar licanantay, which means Atacama bones in the indigenous Kunza language. The remains will eventually be exhibited in Chile's Museum of Natural History. The head of the museum's palaeontology area, David Rubilar, said: "This represents a relevant milestone for the Chilean palaeontological heritage." This is the third dinosaur named from Chile and the third titanosaur from the western side of the Andes in South America, the team said. In 2014, one of biggest dinosaurs ever discovered was unearthed in Argentina, also a titanosaur whose estimated length was more than 37m.

4-19-21 Here’s what we know about B.1.1.7, the U.S.’s dominant coronavirus strain
The variant appears to be more contagious and deadlier, but is still susceptible to vaccines. In December 2020, health officials in the United Kingdom announced that a new coronavirus variant was rapidly spreading across the region. Weeks later, U.S. officials found the first case in the United States (SN: 12/22/20). And by early April, the variant had become the most common form of the coronavirus identified across the country, an event that the U.S. Centers for Disease Control and Prevention had warned in January might happen (SN: 1/15/21). The news came amid a surge in coronavirus cases in many states, including Michigan, where the new variant, dubbed B.1.1.7, makes up nearly 58 percent of genetically screened samples collected as of March 27. The variant is less prevalent in California, New York and other states, where homegrown versions of concerning coronavirus variants are currently causing the majority of cases instead. Following the emergence of the variant in the United Kingdom, scientists have worked to get a handle on how mutations in the virus’s genetic blueprint might change its behavior, amid concerns that the virus might have gained the ability to evade vaccines or cause more severe disease. Here’s what researchers have learned so far about B.1.1.7. Rapid spread of the coronavirus among people in a corner of London that was linked to the emergence of a variant was what first raised health officials’ concerns. In the months since, multiple studies support that initial finding that B.1.1.7 is more contagious than previous versions of the virus, on the order of around 40 to 70 percent. The current hypothesis for why the variant is more transmissible is that a mutation in the spike protein — which helps the coronavirus break into cells — allows the virus to attach more tightly to the cellular protein that lets it enter a new cell. That leads to a higher amount of virus in the body and a more transmissible virus, says Eleni Nastouli, a clinical virologist at University College London.

4-19-21 America's untenable happiness imperative
How COVID-19 exposed our culture's relentless pressure to be positive. here were many good reasons not to be happy in America this winter. By January, an average of 3,100 people were dying every day from COVID-19. And, if you were lucky enough to be spared from the most acute impacts of the virus, there was still plenty of isolation, anxiety, grief, and feelings of helplessness to go around. Meanwhile, as the pandemic raged on, we watched a violent and deadly insurrection at the nation's capital that served as a finale to the most unhinged and rancorous presidency of my lifetime. After four years of watching the nation splinter and smoke and shatter and beat itself up, on January 6, the figurative became real. Added to all of this was a brutal recession, a series of unusual and extreme weather events, and news reports about alarming, non-climate-or-pandemic-related threats to human survival. More recently, mass shootings and police killings have made a devastating return to our streets and social media feeds. And yet despite this abundance of bad news — which included, for me, a months-long string of rejections for a book project that I had poured years into — I realized at some point that I was still feeling bad about the fact that I wasn't feeling happier. In the rare times when I socialized, whether that was on the phone or outdoors and masked, I felt slightly ashamed that I wasn't more energetic and chipper. In quieter moments by myself, I noticed a nagging feeling of self-reproach for not feeling more content or buoyant. I knew this wasn't rational. More than perhaps any other time in my life, this cursed winter had given me, and millions of others, a long list of logical reasons for not feeling particularly cheery. And yet there it was. As someone with a history of anxiety and depression, I wasn't entirely surprised by this. But I was intrigued. Because while certainly some of this guilt could be traced back to the bad feelings factory that is my psyche, I don't think this explained all of it. I was — and still am — convinced that some of the happiness inadequacy I felt was a reflection of the country and culture where I live. For 36 years, I have absorbed the American pressure to be bright, shiny, happy, and perpetually laughing. But for the first time, in the extremity of the pandemic, the senses of how I was supposed to feel and how I actually felt had shifted far enough to leave a gulf between them that was too wide to ignore. Was this American pressure to be happy real or imagined? Where does it come from? Is it possible to be happy as often as Americans are expected to be? And what would it mean to finally opt out? The word "happiness," of course, appears in one of the most famous sentences in U.S. history: "We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness." But at some point, that crucial bit of hedging contained in the words "pursuit of" seemed to dissolve, and left us with a culture that views abiding happiness as a birthright. It's hard to pinpoint exactly when this happened. Though it was certainly visible to the British social theorist Harriet Martineau, who in her 1838 book Retrospect of Western Travel, described "the inexhaustible American mirth" and noted of Americans that, "One of the rarest characters among them, and a great treasure to all his sportive neighbours, is a man who cannot take a joke." In the history of this country, "the feeling, the imperative… to feel happy is deeply rooted historically and pervasive," says Daniel Horowitz, emeritus professor of American Studies at Smith College and author of the book Happier? The History of a Cultural Movement That Aspired to Transform America.

4-17-21 People with rare blood clots after a COVID-19 jab share an uncommon immune response
Some who get AstraZeneca’s or Johnson & Johnson’s shots make antibodies that spark clots. Evidence is building that an uncommon immune response is behind dangerous, but incredibly rare, blood clots associated with some COVID-19 vaccines. But the good news is that there is a test doctors can use to identify it and get patients the right care. A small number of people out of the millions vaccinated with AstraZeneca’s or Johnson & Johnson’s COVID-19 shots have developed severe blood clots, such as ones in the sinuses that drain blood from the brain (SN: 4/7/21; 4/13/21). A few have died. Studies suggest that some inoculated people develop an immune response that attacks a protein called platelet factor 4 or PF4, which makes platelets form clots. Those platelets get used up before the body can make more. So these patients wind up with both the rare clots and low levels of blood platelets. Of 23 patients who received AstraZeneca’s jab and had symptoms of clots or low platelets, 21 tested positive for antibodies to PF4, researchers report April 16 in the New England Journal of Medicine. Of those, 20 people developed blood clots. The finding adds to previous studies that found the same antibodies in additional patients who got AstraZeneca’s shot and had the dangerous clots. Five out of six women who had clots after receiving Johnson & Johnson’s shot in the United States also had PF4 antibodies, health officials said April 14 during an Advisory Committee on Immunization Practices meeting. That advisory group to the U.S. Centers for Disease Control and Prevention is assessing what needs to be done to lift a temporary pause on administering the Johnson & Johnson jab that was prompted by blood clot concerns (SN: 4/13/21). One man had developed brain sinus clots during the shot’s clinical trial and a seventh case is under investigation, the pharmaceutical company said during the meeting.

4-16-21 Human cells grown in monkey embryos spark ethical debate
Monkey embryos containing human cells have been made in a laboratory, a study has confirmed. The research, by a US-Chinese team, has sparked fresh debate into the ethics of such experiments. The scientists injected human stem cells - cells that have the ability to develop into many different body tissues - into macaque embryos. The developing embryos were studied for up to 20 days. Other so-called mixed-species embryos, or chimeras, have been produced in the past, with human cells implanted into sheep and pig embryos. The scientists were led by Prof Juan Carlos Izpisua Belmonte of the Salk Institute in the US, who, in 2017, helped make the first human-pig hybrid. Their work could pave the way in addressing the severe shortage in transplantable organs as well as help understand more about early human development, disease progression and ageing, he said. "These chimeric approaches could be really very useful for advancing biomedical research not just at the very earliest stage of life, but also the latest stage of life." He maintained that the study, published in the journal Cell, had met the current ethical and legal guidelines. "Ultimately, we conduct these studies to understand and improve human health," he said. Some scientists have, however, raised concerns about the experiment, arguing that while the embryos in this case were destroyed at 20 days, others could try to take the work further. They are calling for public debate over the implications of creating part human/part nonhuman chimeras. Commenting on the research, Dr Anna Smajdor, lecturer and researcher in biomedical ethics at the University of East Anglia's Norwich Medical School, said it posed "significant ethical and legal challenges". She added: "The scientists behind this research state that these chimeric embryos offer new opportunities, because 'we are unable to conduct certain types of experiments in humans'. But whether these embryos are human or not is open to question."

4-16-21 Facebook says its AI could help find drug combinations to treat cancer
Facebook claims that its new artificial intelligence can predict the way drugs interact with each other inside cells quicker than existing methods, enabling speedier discovery of new drug combinations to treat illnesses like cancer, but some researchers say it may not translate into results that will be useful in humans. The system, developed by Facebook AI Research and the Helmholtz Centre in Munich, Germany, is claimed to be the first easy-to-use AI model able to estimate how different drugs will work in the body. It could speed up our ability to uncover new treatments for diseases like cancer. “Drug research often takes half a decade to develop a compound,” says Fabian Theis at the Helmholtz Centre, one of the authors of the work. The model works by measuring how individual cells change in response to treatment from a particular set of drugs and recording those responses. Such an approach could theoretically help tackle cancer tumours, which vary from person to person and react differently to the same treatment, says Eytan Ruppin at the US National Cancer Institute. The AI factors in variables including the type of drug, what it is used in combination with, the dosage level, the time it is taken and the type of cell it targets. It can then use that information to predict the effect of drug combinations it hasn’t yet seen. The research team behind it says humans can’t make these kinds of predictions: if they were given a pool of 100 different drugs, and asked to choose five to be given in three different doses – not uncommon in cancer treatment – there could be 19 billion possible drug regimes. The team tested the AI’s predictions against known combinations of drugs and found it was able to accurately forecast cell responses with over 90 per cent accuracy, says Theis. Unsurprisingly, the more drugs put into the model that the AI has seen before, the better its results.

4-16-21 The alphabet may have been invented 500 years earlier than we thought
The early history of the alphabet may require rewriting. Four clay artefacts found at an ancient site in Syria are incised with what is potentially the earliest alphabetic writing ever found. The discovery suggests that the alphabet emerged 500 years earlier than we thought, and undermines leading ideas about how it was invented. A popular idea is that the alphabet first appeared in Egypt about 3800 years ago, when 20 or so Egyptian hieroglyphs were repurposed as the first alphabet’s letters. The script was then used to write down words in one or more of the ancient languages spoken in south-west Asia at the time. But a discovery at the roughly 4300-year-old site of Umm el-Marra in Syria challenges this narrative. During excavations there in 2004, Glenn Schwartz at Johns Hopkins University in Maryland and his colleagues found four lumps of clay each the size and shape of a human finger. The clay fingers are each inscribed with between one and five symbols, and Schwartz has spent the past 17 years trying to understand them. “When I first saw them, I thought: this looks like writing,” says Schwartz, but it was clearly unlike the cuneiform writing typical of the time and place. After considering and rejecting other possibilities – that, for instance, the symbols were from the script used by the Indus Civilisation – Schwartz now argues that the symbols may be early alphabetic letters. He thinks versions of the letters A, L, O and K are present, although it isn’t clear what words the letters might spell out. The discovery has perplexed some researchers of the early alphabet. If the clay fingers are as old as claimed, they would “blow our current theories about the invention of the alphabet clear out of the water”, says Aaron Koller at Yeshiva University, New York.

4-16-21 Neandertal DNA from cave mud shows two waves of migration across Eurasia
Genetic material left behind in sediments could yield troves of data. Neandertal DNA recovered from cave mud reveals that these ancient humans spread across Eurasia in two different waves. Analysis of genetic material from three caves in two countries suggests an early wave of Neandertals about 135,000 years ago may have been replaced by genetically and potentially anatomically distinct successors 30,000 years later, researchers report April 15 in Science. The timing of this later wave suggests potential links to climate and environmental shifts. By extracting genetic material from mud, “we can get human DNA from people who lived in a cave without having to find their remains, and we can learn interesting things about those people from that DNA,” says Benjamin Vernot, a population geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. A few years ago, scientists showed that it’s possible to extract prehistoric human DNA from dirt, which contains genetic material left behind by our ancestors from skin flakes, hair or dried excrement or bodily fluids such as sweat or blood. Genetic analysis of ancient sediments could therefore yield valuable insights on human evolution, given that ancient human fossils with enough DNA suitable for analysis are exceedingly rare (SN: 6/26/19). Until now, the ancient human DNA analyzed from sediments came from mitochondria — the organelles that act as energy factories in our cells — not the chromosomes in cell nuclei, which contain the actual genetic instructions for building and regulating the body. Although chromosomes hold far more information, retrieving samples of this nuclear DNA from caves proved challenging because of its relative scarcity. A human cell often possesses thousands of copies of its mitochondrial genome for every one set of chromosomes, and the vast majority of any DNA found in ancient dirt belongs to other animals and to microbes.

4-15-21 Switching beef for chicken could reduce water footprint of US diets
Simple changes to US diets may help to save water. Five billion people globally could be facing water scarcity by 2050 if we don’t learn to use it more wisely in the face of more severe droughts connected to climate change. But a study focusing on US consumers shows they can help through dietary choices. To examine how our food choices impact water resources, Martin Heller at the University of Michigan and his colleagues studied the diets of 16,800 people in the US. They calculated each person’s impact on water scarcity based on the types of foods they consumed, the irrigation water used in the production of these foods and the water scarcity in the regions where they were farmed. The researchers found that, for the average US diet, beef consumption contributed most to water scarcity. Other foods that tended to require intense water use included almonds, cashews, walnuts, avocado, asparagus, broccoli and cauliflower. Foods that typically had lower impacts on water resources included chicken, peanuts, cabbage, kale, Brussels sprouts, and fresh peas. The findings hint at ways people in industrialised societies could modify their diets to save water, say the researchers. For example, they calculate that swapping 100 grams of beef for chicken could cut the impact on water scarcity of the average US diet by up to 16 per cent, while replacing 100 grams of asparagus with Brussels sprouts could lower it by up to 45 per cent. The important caveat is that the impact of food production on water supplies “can vary dramatically by geographic location”, says Heller. Tomatoes grown in some parts of drought-prone California, for example, require a lot irrigation compared with those grown in Louisiana, where it rains a lot.

4-15-21 Around 2.5 billion Tyrannosaurus rex ever walked the Earth
A total of 2.5 billion Tyrannosaurus rex probably existed during the lifespan of the species, researchers have calculated – suggesting that very few survived as fossils. Charles Marshall at the University of California, Berkeley, and his colleagues used body mass and population density to estimate how many T. rex once lived. Larger animals tend to have a larger individual range, because they need more food to support their body mass than smaller animals, meaning body mass is inversely correlated with population density – a rule known as Damuth’s law. Previous analysis of T. rex fossils shows that the average body mass of an adult was about 5200 kilograms. The team also used climate models and the locations of T. rex remains to estimate that the total geographic range of the species was about 2.3 million square kilometres across North America. Using these figures and data from living species, the team estimated that there was around one T. rex for every 100 square kilometres in North America. “This would mean there was about 20,000 adult T. rex at any given time,” says Marshall. Previous research shows T. rex lived into its late 20s and, using this figure, the team estimates that 2.5 billion T. rex spanning 127,000 generations graced our planet between 69 and 66 million years ago, the lifespan of the species. Estimates of population size for long-extinct animals are rare because there are so few fossils. This estimate for adult T. rex suggests a very low fossil incidence rate – it would mean only one in 80 million T. rex survived as fossilised remains. “This question has been in my head for years,” says Marshall. “I would ask the question every time I held a fossil in my hand.” Marshall and his colleagues acknowledge that their estimates could vary because there are some uncertainties in the data – there could have been anywhere from 140 million to 42 billion individuals over the time period they existed. There are animals with similar body masses that have very different population densities. “For example, spotted hyenas have the same body mass as jaguars, but are about 50 times more densely populated,” says Marshall.

4-15-21 The P.1 coronavirus variant is twice as transmissible as earlier strains
The variant first found in Brazil can evade some immunity from previous infections. The P.1 coronavirus variant first identified in Brazil may be twice as transmissible as earlier strains and may evade up to nearly half of immune defenses built during previous infections, a new study suggests. According to data collected in Manaus, Brazil, P.1 probably arose in mid-November 2020 in the city, researchers report April 14 in Science. The variant quickly rose to prominence there and spread to the rest of Brazil and at least 37 other countries, including the United States. Earlier examinations of the variant’s genetic makeup have shown that P.1 contains many differences from earlier strains, including 10 amino acid changes in the spike protein, which helps the virus infect cells. Three of those spike protein changes are of concern because they are the same mutations that allow other worrisome variants to bind more tightly to human proteins or to evade antibodies (SN: 2/5/21). Simulations of P.1’s properties suggest that the variant is 1.7 to 2.4 times more transmissible than the previous SARS-CoV-2 strain. It is not clear whether that increase in transmissibility is because people produce more of the virus or have longer infections. Some studies have hinted that people who previously had COVID-19 can get infected with P.1. The new study suggests that people who had earlier infections have about 54 percent to 79 percent of the protection against P.1 as they do against other local strains. That partial immunity may leave people vulnerable to reinfection with the variant. Whether the virus makes people sicker or is more deadly than other strains is not clear. The researchers estimate that coronavirus infections were 1.2 to 1.9 times more likely to result in death after P.1 emerged than before. But Manaus’ health care system has been under strain, so the increase in deaths may be due to overburdened hospitals.

4-15-21 Why are so many babies dying of Covid-19 in Brazil?
More than a year into the pandemic, deaths in Brazil are now at their peak. But despite the overwhelming evidence that Covid-19 rarely kills young children, in Brazil 1,300 babies have died from the virus. One doctor refused to test Jessika Ricarte's one-year-old son for Covid, saying his symptoms did not fit the profile of the virus. Two months later he died of complications from the disease. DAfter two years of trying, and failed fertility treatments, teacher Jessika Ricarte had all but given up on having a family. Then she fell pregnant with Lucas. "His name comes from luminous. And he was a light in our life. He showed that happiness was much more than we imagined," she says. She first suspected something was wrong when Lucas, always a good eater, lost his appetite. At first Jessika wondered if he was teething. Lucas's godmother, a nurse, suggested that he might just have a sore throat. But after he developed a fever, then fatigue and slightly laboured breathing, Jessika took him to hospital, and asked for him to be tested for Covid. "The doctor put on the oximeter. Lucas's levels were 86%. Now I know that is not normal," says Jessika. But he was not feverish, so the doctor said: "My dear, don't worry. There's no need for a Covid test. It's probably just a minor sore throat." He told Jessika that Covid-19 was rare in children, gave her some antibiotics and sent her home. Despite her misgivings, there was no option to have Lucas tested privately at the time. Jessika says that some of his symptoms dissipated at the end of his 10-day antibiotics course, but the tiredness remained - as did her concerns about coronavirus. "I sent several videos to his godmother, my parents, my mother-in-law, and everyone said that I was exaggerating, that I should stop watching the news, that it was making me paranoid. But I knew that my son was not himself, that he was not breathing normally."

4-14-21 How to keep your brain healthy: The 7 things you should do every day
Keeping your brain in good shape will not only stave off mental decline, but can also improve your relationships and boost your well-being – and it's never too late to make a difference. ONE sultry afternoon in 1862 in Luxor in Egypt, Edwin Smith was haggling with an antiquities dealer for an unknown papyrus. Though he suspected its importance, Smith couldn’t know it would turn out to be not just the earliest known medical text, at over 4000 years old, but the first ever documented mention of the brain. And what did it say about the most complex entity in the known universe? That it was “cranial offal”, to be unceremoniously trashed during embalming. We have learned rather a lot about the brain since then. Even so, it is only in the past 25 years that learning how best to look after the stuff upstairs has become a major priority for researchers. It is easy to be resigned to the idea that as we get older, our brains wind down, memories decline and reactions slow. But a wealth of new research shows that it is never too late to improve our brain health – a concept that goes way beyond the absence of disease. A long view of how, across some 2 million years, evolution has shaped the function of our brains is revealing new and unexpected ways to keep them healthy for longer. In 2018, an international group of specialists forming the Global Council on Brain Health identified a surprisingly simple test to assess whether your brain is in good shape: whether you function well in daily life. This may even sound overly simplistic, but the group, for which I am a special adviser, found that the brain requires three vital functions to work together seamlessly: executive function, or our ability to think and reason; social cognition, which enables us to interact successfully with others; and emotion regulation, through which we generate our sense of well-being. 1. Go with your gut 2. Watch what you eat 3. Get moving 4. Keep in touch 5. Learn a new skill 6. Stay in rhythm 7. Do what makes you happy 8. Chew it over 9. Sex on the brain

4-14-21 We have overlooked a crucial cause of the world's nutrition crisis
Attempts to tackle undernutition in children around the world often overlook an important part of the puzzle, says Priti Parikh. THE world’s children are in the midst of a nutrition crisis. At least one in three children under 5 globally experiences some form of undernutrition. Not only can this result in them being underweight for their age, it can also lead to stunted growth and affect brain development. But tackling this problem isn’t simply about food and healthy diets. There is an often overlooked piece of the puzzle that is needed to make a difference: sanitation. Figures from the World Health Organization show that around 45 per cent of deaths among children under 5 are linked to undernutrition, with most of these occurring in low and middle-income countries. The pandemic has worsened nutrition crises. Around 55 million children were considered underweight for their height before covid-19 struck, but since then 7 million more have been added to this category. Current global food stocks are higher than previous years, so a food shortage alone is unlikely to be driving this. A few years ago, Robert Chambers and Gregor von Medeazza at the UK-based Institute of Development Studies reviewed 250 papers on links between gaps in water and sanitation services and nutrition, chronic diarrhoea and disease to help understand the picture. They found that undernutrition is higher when families lack sanitation facilities in their own homes – an issue that isn’t limited to low-income households – and concluded that sanitation and hygiene are overlooked in nutrition studies. This also matches a pattern I have seen first hand. My colleagues and I studied nine villages in Rajasthan state in India where half of children under 5 have stunted growth for their age. We observed existing water and sanitation facilities, interviewed families and held group discussions on nutrition and living conditions.

4-14-21 Exploring 'Aquaterra', the drowned continent walked by our ancestors
A continent's worth of land inhabited by ancient people has been submerged by rising seas over the past 20,000 years. Now we're discovering its secrets. BEAUTIFUL corals, graceful sea turtles and 4-metre-long tiger sharks. It is easy to see why tourists flock to the Dampier Archipelago in north-west Australia to dive among the thrilling – if occasionally intimidating – marine life. But these seas contain something that isn’t advertised by tour guides. When Chelsea Wiseman and her colleagues went diving here in 2019, they found stone tools on the seabed. The artefacts were last touched by human hands at least 7000 years ago, before the sea rose, the land drowned and the sharks moved in. “We were ecstatic, just blown away, to find the tools,” says Wiseman, an archaeologist at Flinders University in Adelaide, Australia. And with good reason. During the early millennia of human evolution, sea levels were mostly much lower than they are today, with huge areas of what is now submerged coastal shelf inhabited by our ancient relatives. What they were up to in these Stone Age coastal areas has long been a mystery because studying these underwater sites is so hard. With the archaeology of our coastal waters largely unexplored, we are missing a huge piece of human history. Now, however, that is changing. Underwater archaeology like that carried out by Wiseman and her team is already showing us how people lived and thrived along Stone Age coasts. It even suggests that, as the seas rose, people took action to hold them back, in a poignant foreshadowing of today. And as the coasts were a crucial route for Stone Age travellers, studying them is changing our understanding of how and when humans began spreading around the world. Underwater archaeology began in the 19th century. For decades, it mostly involved investigating shipwrecks, and we tended to learn about ancient maritime life. For instance, we found that civilisations that existed around the edges of the Mediterranean Sea 3500 years ago often shipped metals in the right ratios to be smelted into strong alloys like bronze. This focus on wrecks was understandable, says Jonathan Benjamin at Flinders University, who led the work at the Dampier Archipelago as part of a project called the Deep History of Sea Country. Shipwrecks are often easy to find. “I call them the castles of the sea,” he says.

4-14-21 How a return to offices after covid-19 lockdown affects mental health
A RETURN to the workplace can’t come soon enough for some people. Others, however, may be experiencing post-lockdown anxiety, triggered in part by thoughts of sharing indoor space, socialising with other people or commuting on crowded buses or trains. The covid-19 pandemic has had a serious impact on mental health. A study of more than 53,000 people in the UK that tracked mental health before the pandemic and into the first lockdown showed an immediate increase in mental distress in people aged 16 and older (The Lancet, doi.org/gg5ngp). Despite a slight improvement in anxiety levels over the past year, they are significantly worse than they were before the pandemic, according to the UK Office for National Statistics (ONS). The effect is stronger for people in a lower socio-economic bracket. Medical insurance company Bupa tells New Scientist it has seen twice as many calls to its mental health direct access service as it did two years ago. New stressors arrive as lockdowns end. Anxiety UK polled 900 people and found that of those who were feeling anxious about the lifting of restrictions, 46 per cent cited pressure to socialise as their biggest concern, while 23 per cent were worried about public transport and 20 per cent were anxious about returning to work. About 23 per cent felt that they would be pressured to go back to the office sooner than they would like. But it wouldn’t necessarily be best for our mental health if we continued to work from home, says Peter Smith at the University of Toronto, Canada. Smith and his colleagues studied people working in different environments in Canada in 2020. They found that anxiety and depression were lower for those working remotely than for people still working on site or who had lost their jobs. However, when workplaces had adequate infection control schemes, on-site workers had the lowest prevalence of anxiety (Annals of Work Exposures and Health, doi.org/f58k).

4-14-21 5 steps to make offices as coronavirus-proof as possible
MANY more people in the UK are returning to their workplaces as coronavirus lockdowns ease. Some US companies are also attempting a return: Google is allowing workers to return on a voluntary basis, for instance. More will do so in coming months. Returning safely will involve a mix of strict measures and tailored arrangements to make employees feel safe and happy. “It’s not a one-size-fits-all problem,” says Michael Tildesley at the University of Warwick, UK. From 12 April, many premises in England were allowed to reopen, including all shops, hairdressers and libraries. UK prime minister Boris Johnson has argued that most people will return to their workplaces full-time and that there won’t be a permanent shift towards working from home. With more than 11,000 covid-19 cases in the UK in the past week, there are risks associated with going back to the workplace. It may not cause many additional deaths – because almost half of the population has received at least one dose of a vaccine, including the majority of those who are most vulnerable – but it will raise the number of cases. That increase has two consequences. First, 1 in 10 infected people seem to develop long covid, which can include exhaustion and concentration problems. Second, more cases means more opportunities for the virus to mutate to become more dangerous. The risk of transmission of SARS-CoV-2, which causes covid-19, needs to be reduced as much as possible in the workplace, says Lisa Lee at Virginia Tech in Blacksburg. The key to this is to follow an established risk management strategy called the Hierarchy of Controls, says Catherine Noakes at the University of Leeds, UK. This involves doing the most effective things first, and only using less effective strategies as a fallback.

4-14-21 STEM’s racial, ethnic and gender gaps are still strikingly large
Black and Hispanic workers remain underrepresented while it varies widely by field for women. Efforts to promote equity and inclusion in science, technology, engineering and math have a long way to go, a new report suggests. Over the last year, widespread protests in response to the police killings of George Floyd, Breonna Taylor and other unarmed Black people have sparked calls for racial justice in STEM. Social media movements such as #BlackinSTEM have drawn attention to discrimination faced by Black students and professionals, and the Strike for Black Lives challenged the scientific community to build a more just, antiracist research environment (SN: 12/16/20). An analysis released in early April of federal education and employment data from recent years highlights how wide the racial, ethnic and gender gaps in STEM representation are. “This has been an ongoing conversation in the science community” for decades, says Cary Funk, the director of science and society research at the Pew Research Center in Washington, D.C. Because the most recent data come from 2019, Pew’s snapshot of STEM cannot reveal how recent calls for diversity, equity and inclusion may have moved the needle. But here are four big takeaways from existing STEM representation data: From 2017 to 2019, Black professionals made up only 9 percent of STEM workers in the United States — lower than their 11 percent share of the overall U.S. workforce. The representation gap was even larger for Hispanic professionals, who made up only 8 percent of people working in STEM, while they made up 17 percent of the total U.S. workforce. White and Asian professionals, meanwhile, remain overrepresented in STEM. Some STEM occupations, such as engineers and architects, skew particularly white. But even fields that include more professionals from marginalized backgrounds do not necessarily boast more supportive environments, notes Jessica Esquivel, a particle physicist at Fermilab in Batavia, Ill., not involved in the research.

4-14-21 Surprisingly, humans recognize joyful screams faster than fearful screams
It’s a twist to a long-held idea that our brains are wired to quickly detect threats first. Screams of joy appear to be easier for our brains to comprehend than screams of fear, a new study suggests. The results add a surprising new layer to scientists’ long-held notion that our brains are wired to quickly recognize and respond to fearful screams as a survival mechanism (SN: 7/16/15). The study looked at different scream types and how listeners perceive them. For example, the team asked participants to imagine “you are being attacked by an armed stranger in a dark alley” and scream in fear and to imagine “your favorite team wins the World Cup” and scream in joy. Each of the 12 participants produced seven different types of screams: six emotional screams (pain, anger, fear, pleasure, sadness, and joy) and one neutral scream where the volunteer just loudly yelled the ‘a’ vowel. Separate sets of study participants were then tasked with classifying and distinguishing between the different scream types. In one task, 33 volunteers were asked to listen to screams and given three seconds to categorize them into one of the seven different screams. In another task, 35 different volunteers were presented with two screams, one at a time, and were asked to categorize the screams as quickly as possible while still trying to make an accurate decision about what type of scream it was, either alarming screams of pain, anger or fear or non-alarming screams of pleasure, sadness or joy. It took longer for participants to complete the task when it involved fear and other alarming screams, and those screams were not as easily recognizable as non-alarming screams like joy, the researchers report online April 13 in PLOS Biology. In another experiment, 30 different volunteers underwent functional magnetic resonance imaging, or fMRI, while listening to the screams. Less-alarming screams elicited more activity in the auditory and frontal brain regions than more-alarming screams, the team found, though why we respond that way isn’t yet clear.

4-14-21 A coronavirus epidemic may have hit East Asia about 25,000 years ago
Descendants of the outbreak may have inherited some DNA that affects their response to COVID-19. An ancient coronavirus, or a closely related pathogen, triggered an epidemic among ancestors of present-day East Asians roughly 25,000 years ago, a new study indicates. Analysis of DNA from more than 2,000 people shows that genetic changes in response to that persistent epidemic accumulated over the next 20,000 years or so, David Enard, an evolutionary geneticist at the University of Arizona in Tucson, reported April 8 at the virtual annual meeting of the American Association of Physical Anthropologists. The finding raises the possibility that some East Asians today have inherited biological adaptations to coronaviruses or closely related viruses. The discovery opens the way to exploring how genes linked to ancient viral epidemics may contribute to modern disease outbreaks, such as the COVID-19 pandemic. Genes with ancient viral histories might also provide clues to researchers searching for better antiviral drugs, although that remains to be demonstrated. Enard’s group consulted a publicly available DNA database of 2,504 individuals from 26 ethnic populations on five continents, including Chinese Dai, Vietnamese Kinh and African Yoruba people. The team first focused on 420 proteins known to interact with coronaviruses, including 332 that interact with SARS-CoV-2, the virus that causes COVID-19. These interactions could range from boosting immune responses to making it easier for a virus to hijack a cell. Substantially increased production of all 420 proteins, a sign of past exposures to coronavirus-like epidemics, appeared only in East Asians. Enard’s group traced the viral responses of 42 of those proteins back to roughly 25,000 years ago. An analysis of the genes known to orchestrate production of those proteins determined that specific variants became more common around 25,000 years ago before leveling off in frequency by around 5,000 years ago. That pattern is consistent with an initially vigorous genetic response to a virus that waned over time, either as East Asians adapted to the virus or as the virus lost its ability to cause disease, Enard said. Twenty-one of the 42 gene variants act either to enhance or deter the effects of a wide array of viruses, not just coronaviruses, suggesting that an unknown virus that happened to exploit similar proteins as coronaviruses could have instigated the ancient epidemic, Enard said.

4-14-21 ‘First Steps’ shows how bipedalism led humans down a strange evolutionary path
A new book argues that upright walking had profound effects on human anatomy and behavior. No other animal moves the way we do. That’s awfully strange. Even among other two-legged species, none amble about with a straight back and a gait that, technically, is just a form of controlled falling. Our bipedalism doesn’t just set us apart, paleoanthropologist Jeremy DeSilva posits; it’s what makes us human. There’s no shortage of books that propose this or that feature — tool use or self-awareness, for example — as the very definition of humankind. But much of our supposed uniqueness doesn’t stand up to this tradition. In First Steps, DeSilva takes a slightly different approach. Our way of walking, he argues, set off an array of consequences that inform our peculiar evolutionary history. DeSilva starts his tour through the annals of bipedalism with other upright organisms. Tyrannosaurus and ancient crocodile relatives are trotted out to show how they moved on two legs, thanks to long, counterbalancing tails (SN: 6/12/20). DeSilva stumbles a little here, like arguing that “bipedalism was not a successful locomotion for many dinosaur lineages.” An entire group — the theropods — walked on two legs and still do in their avian guises. But the comparison with dinosaurs is still worthwhile. With no tail, the way we walk is even stranger. “Let’s face it,” DeSilva writes, “humans are weird.” Each following chapter gets more surefooted as DeSilva guides readers through what we’ve come to know about how our ancestors came to be bipedal. This is breezy popular science at its best, interweaving anecdotes from the field and lab with scientific findings and the occasional pop culture reference. DeSilva gets extra credit for naming oft-overlooked experts who made key discoveries.

4-14-21 ‘Monkeydactyl’ may be the oldest known creature with opposable thumbs
The winged reptile’s dexterity may have helped it climb trees during the age of dinosaurs. Future Jurassic Park films could feature one weird new beast in the menagerie: a pterosaur nicknamed Monkeydactyl for its opposable thumbs. This flying reptile from the Jurassic Period may be the earliest known animal that could touch the insides of its thumbs to the insides of its other fingers, researchers report online April 12 in Current Biology. Such dexterity probably allowed Monkeydactyl to climb trees about 160 million years ago, perhaps to feed on insects and other prey that nonclimbing pterosaurs did not, the researchers say (SN: 12/21/18). The latter half of the creature’s official name, Kunpengopterus antipollicatus, comes from the words “opposite” and “thumb” in ancient Greek. Monkeydactyl’s fossilized remains, unearthed in northeastern China in 2019, are embedded in rock. So the team used micro-CT scanning to create a 3-D rendering of the fossil. “With this detail, we’re able to look at the fossil from any angle, and make sure that the bones are in their right [original] place,” says study coauthor Rodrigo Pêgas, a paleontologist at the Federal University of ABC in São Bernardo, Brazil. Those scans helped confirm that the skeleton had a well-preserved opposable thumb on each hand. “Almost all of the modern animals that have opposable thumbs use them to climb trees,” Pêgas says, including primates and some tree frogs. That evidence, along with the apparent flexibility of Monkeydactyl’s joints, suggests this species was well suited to clambering through tree branches.

4-13-21 What causes the rare blood clots linked with some covid-19 vaccines?
Use of the Johnson & Johnson covid-19 vaccine has been suspended in the US after six people experienced blood clots, out of 6.8 million who received the vaccine in the country. The cases seem to be similar to the rare blood clots seen in recipients of the Oxford/AstraZeneca vaccine, which has caused some countries to restrict its use. The blood clot syndrome involves an unusual type of clot, often one that forms in the brain – called cerebral venous sinus thrombosis or CVST – coupled with low levels of platelets, small particles in the blood that stick together to make clots. It has been seen mainly in people under about 60, and more often in women than men. But the sex difference may be because more women have been vaccinated, as they comprise more healthcare workers and care home staff. In an analysis of 79 UK cases seen after the Oxford/AstraZeneca jab, they occurred at the same rate in men and women, says Munir Pirmohamed, chair of the UK’s Commission on Human Medicines. The overall rate was four cases per million people who have received the vaccine in the UK. It is unknown why younger people seem more at risk, but the age distribution is partly why some countries have said this vaccine should only be given to those above a certain age. The other reason is that older people are more at risk from covid-19 itself, so the benefit of the vaccine should outweigh the risk. The six cases of CVST newly reported in recipients of the Johnson & Johnson vaccine, one of which was fatal, were all in women aged between 18 and 48. Johnson & Johnson announced today it would delay the European roll-out of its product. “We have been working closely with medical experts and health authorities, and we strongly support the open communication of this information to healthcare professionals and the public,” the firm said in a statement.

4-10-21 Basic income trial is testing how money affects child development
Growing up in poverty can have long-term negative consequences for children. Now, a study offering unconditional cash to a group of mothers on low-incomes in the US is beginning to discover the precise role of parental income in child development. It is the first randomised trial to look at whether a basic income might affect the way a child’s brain develops in this critical period. Studies of children born into families with low income have found they tend to have more behavioural problems and are behind their peers when they start school. We know that the first few years of a child’s life are the most influential for their development, and brain development is particularly rapid in early childhood and therefore more likely to be influenced by the environment. However, it isn’t clear whether income directly causes these outcomes, or whether they are a result of other factors associated with growing up in poverty. To find out, Kimberly Noble at Columbia University and her colleagues approached women on low incomes who had just given birth at four sites in the US, and asked them if they would take part in a study following their child’s development. Around 1000 women accepted and were randomly assigned to one of two groups. The first group, consisting of 40 per cent of the women, received an unconditional monthly cash gift which added up to $333 per month, and the other group received $20 per month. Both groups will receive the money for the first 40 months of their child’s life. The first babies in the study were born in May 2018, and the team have been following up every year. Preliminary findings from the first year were presented this week at the virtual Society for Research in Child Development Conference. “To date, the dots are not connected in a careful scientific way,” one of the study authors Katherine Magnuson at the University of Wisconsin-Madison told the conference. “We still don’t know whether the types of early experiences that poverty creates for children will directly impact their early development and specifically their brain development in any meaningful way.”

4-10-21 Animals with weird neurons may rewrite the story of brain evolution
Marine animals called comb jellies have nervous systems unlike those of any other known animal. Their neurons are oddly shaped and use chemicals not found in those of other animals. “These neurons are quite unique,” says Pawel Burkhardt at the University of Bergen in Norway. The comb jellies’ peculiar neurons may be an adaptation for their lifestyle and the way their bodies work. They also add to the ongoing debate among evolutionary biologists about how the first animal brains evolved. In particular, there is controversy over whether brains evolved once in very early animals, or several times in different groups. Comb jellies, or ctenophores, are one of the oldest animal groups – and the oldest group to have a nervous system. Though they look a bit like jellyfish, they have a distinct evolutionary history. Their name comes from the “combs” that run along the outsides of their bodies. Each comb is a row of tiny tentacles, which propel the comb jelly through the water. Comb jellies don’t have a large central brain. Instead they have a thin net of neurons. “What was elusive so far was what is going on with the nervous system,” says Burkhardt. Neurons in other animals produce characteristic chemicals, in particular, small proteins called neuropeptides. But nobody had identified neuropeptides in comb jelly neurons. Burkhardt’s team studied a comb jelly called Mnemiopsis leidyi, whose genome had already been sequenced. The researchers used a machine-learning tool to predict 129 possible neuropeptides from the genome. They then grew M. leidyi in the lab, and identified 16 of these neuropeptides in their neurons. They were unlike those seen in any other animal. “They took a big risk in taking this approach and I think it paid off,” says Leslie Babonis of Cornell University in New York.

4-9-21 Artificial nervous system senses light and learns to catch like humans
A simple artificial nervous system is able to mimic the way humans respond to light and learn to perform basic tasks. The principle could be used to create more useful robots and prostheses. Humans, when confronted by external stimuli such as heat or light, can react rapidly and automatically – think about how your hand withdraws from a hot surface, or how your leg flicks up when tapped on the knee. These are unconscious responses. But conscious responses, such as catching a ball, must be honed by repeated stimulation. Researchers at three universities in South Korea have developed an artificial system capable of simulating a conscious response to external stimuli. It consists of a photodiode – which converts light into an electrical signal, a transistor acting as a mechanical synapse, an artificial neuron circuit, which acts as the system’s brain, and a robotic hand. When the photodiode detects light, it sends an electrical signal through the transistor that the light is on. That signal is carried to the artificial neuron circuit. There, the message is received, and that circuit then learns how to respond to the signal, sending a command to a robotic hand it controls. At the same time as the light is turned on, starting the whole process off at the photodiode, a ball is dropped from above the hand. The idea is for the contraption to learn how to cup the hand quickly enough to catch the ball. The process is similar to the way our eye transmits electrical signals via synapses to our brain, which then translates those signals, decides on a course of action and sends a command to muscles to move – all within a fraction of a second. In the early stages of the experiment, the brain of the system was slow to translate the light signal into a decision to cup the hand. Before “learning” how to react, the system took 2.56 seconds to do this. After it had been exposed repeatedly to the light signal and allowed time to process what to do, this decreased to 0.23 seconds. The researchers say the artificial neural system is imitating something like a conscious biological response.

4-9-21 'Lost golden city' found in Egypt reveals lives of ancient pharaohs
The discovery of a 3,000-year-old city that was lost to the sands of Egypt has been hailed as one of the most important archaeological finds since Tutankhamun's tomb. Famed Egyptologist Zahi Hawass announced the discovery of the "lost golden city" near Luxor on Thursday. He said the find was the largest ancient city, known as Aten, ever uncovered in Egypt. It was unearthed within weeks of the excavation starting in September 2020. The city dates to the reign of Amenhotep III, one of Egypt's most powerful pharaohs, who ruled from 1391 to 1353 BC. The city continued to be used by pharaohs Ay and Tutankhamun, whose nearly intact tomb was discovered in the Valley of the Kings by British archaeologist Howard Carter in 1922. "The discovery of this lost city is the second most important archaeological discovery since the tomb of Tutankhamun," Betsy Brian, professor of Egyptology at Johns Hopkins University in Baltimore, US, said. She said the city would "give us a rare glimpse into the life of the ancient Egyptians" at the time when the empire was at its wealthiest. The dig revealed a large number of valuable archaeological finds, such as jewellery, coloured pottery, scarab beetle amulets and mud bricks bearing seals of Amenhotep III. The team began excavations on the west bank of Luxor near the Valley of the Kings, some 500 km (300 miles) south of the capital Cairo. "Within weeks, to the team's great surprise, formations of mud bricks began to appear in all directions," Dr Hawass said in his statement. "What they unearthed was the site of a large city in a good condition of preservation, with almost complete walls, and with rooms filled with tools of daily life." Now, seven months after the dig started, several areas or neighbourhoods have been uncovered, including a bakery, an administrative district and a residential area. "Many foreign missions searched for this city and never found it," said Dr Hawass, a former antiquities minister. He said further archaeological work was under way at the site and his team "expects to uncover untouched tombs filled with treasures".

4-9-21 Ancient humans may have had apelike brains even after leaving Africa
Modern humanlike brains may have emerged in an evolutionary sprint about 1.7 million years ago. Even after ancient humans took their first steps out of Africa, they still unexpectedly may have possessed brains more like those of great apes than modern humans, a new study suggests. For decades, scientists had thought modern humanlike organization of brain structures evolved soon after the human lineage Homo arose roughly 2.8 million years ago (SN: 3/4/15). But an analysis of fossilized human skulls that retain imprints of the brains they once held now suggests such brain development occurred much later. Modernlike brains may have emerged in an evolutionary sprint starting about 1.7 million years ago, researchers report in the April 9 Science. What sets modern humans apart most from our closest living relatives, the great apes, is most likely our brain. To learn more about how the modern human brain evolved, the researchers analyzed replicas of the brain’s convoluted outer surface, re-created from the oldest known fossils to preserve the inner surfaces of early human skulls. The 1.77-million to 1.85-million-year-old fossils are from the Dmanisi archaeological site in the modern-day nation of Georgia and were compared with bones from Africa and Southeast Asia ranging from roughly 2 million to 70,000 years old. The scientists focused on the brain’s frontal lobes, which are linked with complex mental tasks such as toolmaking and language. Early Homo from Dmanisi and Africa still apparently retained a great ape–like organization of the frontal lobe 1.8 million years ago, “a million or so years later than previously thought,” says paleoanthropologist Philipp Gunz at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who did not take part in this study.

4-8-21 People expect chocolate to taste bitter if it is in black packaging
People expect chocolate to be more bitter-tasting if it is in black packaging, while yellow and pink packaging is associated with sweeter-tasting chocolate. Iuri Baptista at the University of Campinas in Brazil and his colleagues wanted to investigate how people respond to the colour of chocolate packaging. The researchers sent a survey to 420 people between the ages of 18-60. Half of the participants were in Brazil and the other half were in France. The survey contained two photographs of milk chocolate bars and two of dark chocolate bars. Each chocolate bar came in packaging of a specific colour – either black, blue, brown, green, red, pink or yellow. The participants were asked to rank each chocolate bar on a scale of 1-9 for different attributes, including how sweet or bitter they expected the chocolate to taste. To avoid any bias, they were not told the purpose of the study. People expected both milk and dark chocolates to be the least sweet and most bitter if its packaging was black. Conversely, the participants expected the chocolates in yellow or pink packaging to be the sweetest and least bitter. “The colour of packaging changes how the consumer expects the chocolate to taste,” says Baptista. The participants were also asked how much they expected to like each chocolate bar. Milk chocolate was rated as most likely to be enjoyed if it came in black packaging – but dark chocolate was least likely to be enjoyed when it was placed in exactly the same black packaging. There was no appreciable difference between the responses of the participants in Brazil and those in France. This surprised the team considering both countries have very different chocolate-eating habits, says Baptista. On average, a person in France will eat 7.3 kilograms of chocolate per year versus just 2.8 kilograms in Brazil. French people also eat chocolate with a higher cocoa content than Brazilian people.

4-8-21 People add by default even when subtraction makes more sense
This tendency to think more is better could underlie modern-day excesses, experts say. Picture a bridge made of Legos. One side has three support pieces, the other two. How would you stabilize the bridge? Most people would add a piece so that there are three supports on each side, a new study suggests. But why not remove a piece so that each side has two supports instead? It turns out that getting people to subtract — whether a Lego block, ingredients in a recipe or words in an essay — requires reminders and rewards, researchers report April 7 in Nature. This default to addition isn’t limited to assembling blocks, cooking and writing. Rather, thinking in pluses instead of minuses could well contribute to modern-day excesses such as cluttered homes, institutional red tape and even an overburdened planet, says behavioral scientist Benjamin Converse of the University of Virginia in Charlottesville. “We’re missing an entire class of solutions.” He and his colleagues first observed the behavior when they asked 1,585 study participants to tackle eight puzzles and problems that could be solved by adding or removing some things. For example, one puzzle required shading or erasing squares on a grid to make a pattern symmetric. In another, individuals could add or subtract items on a travel itinerary for the optimal experience. Across all experiments, the vast majority of participants chose addition over subtraction. For instance, out of 94 participants who completed the grid task, 73 added squares, 18 subtracted squares and another three simply reworked the original number of squares. The researchers hypothesized that most participants defaulted to adding because they failed to even think about subtraction. So, through a series of controlled experiments, the team nudged participants toward the minus sign.

4-8-21 AstraZeneca’s COVID-19 vaccine is tied to uncommon blood clots in rare cases
Because the cases are rare, the benefits of the shot still outweigh the risks, experts argue. In another hiccup for AstraZeneca’s COVID-19 vaccine, data suggest it is in fact linked to blood clots that have formed in the brains of some vaccinated people, the European Medicines Agency announced April 7. The blood clots are incredibly rare, EMA experts say. But because COVID-19 itself is deadly and can put people in the hospital, the benefits of the vaccine still outweigh the risks, they say. “We need to use the vaccines that we have to protect us from devastating effects” of COVID-19, Emer Cooke, executive director of the EMA, said in a news conference on April 7. The EMA had previously concluded that the vaccine, developed by AstraZeneca and the University of Oxford, was not linked to blood clots overall (SN: 3/18/21). But experts were uncertain about 18 case reports of blood clots in the sinuses that drain blood from the brain, a rare condition called cerebral venous sinus thrombosis or CVST. Enough data has now accrued to implicate the jab’s involvement in those rare blood clots, meaning CVST and similar conditions should be listed as a possible rare side effect of vaccination, the EMA’s Pharmacovigilance Risk Assessment Committee concluded after reviewing numerous cases reported in the United Kingdom and the European Union. As of March 22, countries had reported 62 cases of CVST out of around 25 million people who got the AstraZeneca vaccine. There were also 24 reported cases of clots in veins that drain blood from the digestive system, called splanchnic vein thrombosis or SVT. Eighteen of the people with CVST or SVT died. It’s still unknown how the vaccine could cause blood clots. One potential explanation is that some people develop an immune response that attacks platelets, making them clump together, Sabine Straus, chair of the EMA committee, said in the news conference. That would make the condition similar to low platelet levels and blood clots sparked by an immune response to the anticoagulant drug heparin. One preliminary study of four people who died from blood clots after vaccination had platelet-binding antibodies in their blood, researchers reported March 29 at Research Square, a preprint server. The study has not yet been reviewed by other scientists.

4-8-21 We can't let vaccines create bad incentives that make things worse
We are starting to vaccinate our way out of the pandemic, but we shouldn't let that make us complacent about the underlying problems, writes Graham Lawton. I RECEIVED the first dose of my covid-19 vaccine a couple of weeks ago, and it felt like a moment of liberation. By coincidence, it went into my arm on the anniversary of the announcement of the UK’s first national lockdown. As I write, we are eagerly anticipating the gradual lifting of the third such lockdown and the return of some freedoms: a walk with friends, a drink in the pub, a swim in a lido. The UK’s well-organised vaccine roll-out has played a huge part in bringing us to this point and we are indebted to the National Health Service – although unlike many of my fellow citizens, I am not prepared to forgive and forget the catalogue of inept and costly government decisions that necessitated a third lockdown in the first place. That aside, I am relieved to be brewing up my first batch of antibodies against the SARS-CoV-2 coronavirus (I assume that my sore arm and throbbing head were signs that my immune system was busy doing that). I also hope everyone who wants to be gets vaccinated soon. But at the same time, I am slightly alarmed at one of the unintended consequences of a hopefully successful global vaccination programme. The source of my alarm is something called moral hazard, which is a familiar concept in the world of climate change. This is the idea that well-intentioned attempts to reduce risk can create perverse incentives to take greater risks. For example, a person who is insured against house fires may be less careful with matches, knowing that if the worst happens the insurance company will pick up the pieces. Don’t get me wrong: I am wholly in favour of covid-19 vaccination. It is the only viable exit strategy from the pandemic and, despite the feverish fantasies of some self-appointed covid-19 sceptics, environmentalists like me don’t wish for perpetual lockdown. So bear with me.

4-8-21 'Exciting' Stone Age discoveries in the Cairngorms
New research has uncovered rare evidence of people living in Scotland's mountains after the end of the last Ice Age. Archaeologists found stone tools and traces of firepits and possible shelters in Deeside in the Cairngorms. Finds from the Mesolithic period, also known as the Middle Stone Age, are rare and usually made in lowland areas. Archaeologists describe the evidence in the Cairngorms as "exciting". The research, published in the Proceedings of the Prehistoric Society, adds to existing evidence from a handful of other upland sites. These include on the mountain Ben Lawers in Perthshire and at locations in Lanarkshire and Dumfries. Evidence for those who lived in Scotland after the end of the last Ice Age about 10,000 years ago can be hard to find, say archaeologists. The population at the time was low and the communities of hunter-gatherers were "mobile, moving around and living off the land". They did not build permanent monuments and their homes were usually temporary. What traces of their lives that can be found often amounts to a handful of tiny stone tools, such as flints, and discoloured soil "that hint at an ancient hearth or the stance of a shelter". Because this evidence has long been buried over time, the "easiest" locations for archaeologists to search are along sea-eroded coastlines or on farmland where farm work can bring buried the evidence closer to the surface. While archaeologists have long suspected Mesolithic communities occupied mountain landscapes, little evidence to support that has been discovered. Now a team made up of students from the universities of Aberdeen and Dublin has uncovered evidence confirming people were living in the Cairngorms from as early as 7500 BC. The team's finds at several archaeological sites - including traces of firepits, flints and possible huts - were made on land owned by the National Trust for Scotland (NTS).

4-8-21 Europe’s oldest known humans mated with Neandertals surprisingly often
The two species regularly interbred by about 45,000 years ago. When some of the earliest human migrants to Europe encountered Neandertals already living there around 45,000 years ago, hookups flourished. Analyses of DNA found in human fossils from around that time — the oldest known human remains in Europe — suggest that interbreeding between Homo sapiens and Neandertals, who were on the fast track to extinction, occurred more commonly than has often been assumed, two new studies suggest. Both reports appear April 7 in Nature Ecology & Evolution. Genetic evidence in the new reports indicates for the first time that distinct human populations reached Europe shortly after 50,000 years ago. Neandertals interbred with all the groups detected so far, ensuring that some of their genes live on today in our DNA. Remains of three H. sapiens individuals unearthed in Bulgaria’s Bacho Kiro Cave yielded nuclear DNA containing Neandertal contributions of about 3 to 4 percent, says a team led by evolutionary geneticist Mateja Hajdinjak of the Francis Crick Institute in London. The ancient DNA came from a tooth and two bone fragments radiocarbon dated to between around 43,000 and 46,000 years ago. Stone tools typical of late Stone Age humans were found in the same sediment as the fossils. “All of the Bacho Kiro individuals had recent Neandertal ancestors, as few as five to seven generations back in their family trees,” Hajdinjak says. Further evidence of ancient interbreeding comes from a nearly complete human skull discovered in 1950 in a cave in what’s now the Czech Republic. About 2 percent of the genes in DNA from that fossil, identified as a female’s, also come from Neandertals, say evolutionary geneticist Kay Prüfer of the Max Planck Institute for the Science of Human History in Jena, Germany, and his colleagues. Analysis of those DNA segments suggest she also lived around 45,000 years ago.

4-7-21 Why the UK changed covid-19 AstraZeneca vaccine advice for under-30s
On 7 April, the UK effectively restricted use of the Oxford/AstraZeneca covid-19 vaccine to people aged 30 and over because of the risk of a rare blood clot syndrome. But other European countries and Canada have broader restrictions, with higher age cut-offs. Why are the regulations different, and what are the implications for vaccine roll-out in the UK? What are the safety concerns over the Oxford/AstraZeneca vaccine? UK and European medicines regulators have been reviewing a small number of people who developed blood clots linked with low levels of platelets – small particles in the blood that normally help in clotting – soon after having the Oxford/AstraZeneca vaccine. Both have now concluded that the clots are possibly caused by the vaccine, although they say the benefits of vaccination for most people outweigh the risks. How should people under 30 weigh the benefits and drawbacks? For healthy people under 30, the health risks from catching covid-19 are low, but there may be a slightly higher rate of the blood clot condition in younger people. So, the UK Joint Committee on Vaccination and Immunisation (JCVI) has said the risk-benefit equation is “more finely balanced” for this group. That means that for people under 30, the chance of the vaccine causing the clotting reaction is a little greater than the risk of severe illness from covid-19. Why are other countries setting the age limit higher? Canada and France have restricted the Oxford/AstraZeneca jab to people 55 and over, while Germany has set the bar at 60, and Iceland 70. These countries seem to have taken a more cautious, broad-brush approach, reasoning that the blood clots have generally been seen in middle-aged people so the vaccine should be withheld below a certain age until we know more. The JCVI, by contrast, today announced results of a detailed analysis, comparing the risk of the suspicious blood clots with the risk of getting badly ill from covid-19 for every age group in 10-year bands. This is why the committee set the age limit at 30.

4-7-21 People are bad at spotting simple solutions to problems
Leonardo da Vinci said that a poet recognises perfection when there is nothing left to remove. In other words, less is more. But when solving problems, people tend to think the other way, adding elements rather than removing them. Gabrielle Adams at the University of Virginia and colleagues asked people to complete several tasks where solutions involved either adding or subtracting parts. All of the experiments were designed so that subtraction would be one of the most efficient options. In one, around 200 people had to alter a Lego building to support a weight in order to gain a $1 bonus. The roof of the building was balancing precariously on just one support. A solution would be to add several bricks to better support the roof, which they were told would cost 10 cents each. Another way of shoring up the structure was to simply remove one brick. Only 41 per cent of the control group opted to remove a brick, but when another group was prompted that removing bricks incurred no cost, this rose to 61 per cent. The team didn’t collect any demographic data for this part of the test. In another task, around 300 people had to make a grid of 100 squares symmetrical by either adding or removing green tiles. When asked to take the test with no practice, only 49 per cent of people opted to remove tiles, but when given three practice runs before taking the test, this rose to 63 per cent. In this test, just over 40 per cent of participants were women. During the research, the team spoke to a company with a newly appointed leader who asked staff for improvement suggestions. For every idea to remove a policy or rule, the leader received eight to add one. In a pre-prepared Q&A, Adams said that balance bikes are a great example of the subtractive approach. “These are kids’ bikes without the pedals or the chain. Most people who have seen a toddler zipping down the street on a balance bike instantly recognise that subtractive invention as superior to the clunky additive change of training wheels.”

4-7-21 Dementia risk doubles if people have both vision and hearing loss
Older adults who start losing both vision and hearing may be at an increased risk of developing dementia. Gihwan Byeon at Kangwon National University Hospital in South Korea and his colleagues studied 6520 people, aged 58 to 101, over six years. At the start of the study, they asked each person to rate their ability to see and hear. The participants also underwent cognitive testing every two years. The team found that 7.6 per cent of those reporting both vision and hearing loss had dementia at the start of the study, and another 7.4 per cent developed it within six years. Meanwhile, only 2.4 per cent of people with only vision or hearing loss had dementia at the start of the study, and another 2.9 per cent developed it by the end of the study. Adjusting for other factors that influence dementia, such as sex, education and income, the researchers estimate that people with impairments of both vision and hearing are twice as likely to develop dementia as people with only one or neither impairment. The results are “very tantalising”, says Jason Warren at University College London. However, the findings must be considered with caution, he adds, as the hearing and vision loss were self-reported rather than measured directly. Even so, this could provide insight into the cognitive decline that people with hearing and vision loss experience, says Warren. “We see and hear with our brains, and the first sign of a failing brain in dementia may well be an inability to navigate the complex sensory environments of everyday life,” he says. Byeon wonders whether the brains of people with both hearing and vision loss might struggle to compensate for the lost senses. Usually, people with impaired vision develop better hearing to compensate, and people with impaired hearing rely more on their vision to help out, he says. “Dual sensory impairment may not be compensated for, making [the brain] more vulnerable to dementia,” he says.

4-7-21 Experimental events offer glimpse of safe, post-lockdown nightlife
FOR a few hours on a Saturday afternoon in March, Simone van Erp did what, for much of the planet right now, would be unthinkable. She took off her mask, brushed up against strangers, danced, sang and shouted as loud as she could – droplets and aerosols be damned – as DJs at the Ziggo Dome in Amsterdam, the Netherlands, spun to a rapturous crowd of 1300. “Everyone was really happy, enthusiastic, screaming and laughing, it was crazy,” says van Erp. “It was a good feeling. You could see that everyone missed normal life.” It has been a year since much of the world has been able to dance and sing in a hot, crowded venue. Now studies are offering clues as to how we can safely reintroduce large gatherings into our lives. During the early days of the coronavirus pandemic, it became clear that mass gatherings can be superspreader events, where just a few infected people can spark a large outbreak. In February 2020, before lockdowns began in the US, a two-day conference in Boston with 175 attendees was identified as the source of an estimated 20,000 cases of covid-19 across the Boston area by May. Now, with mass vaccinations gathering pace globally, while the live entertainment sector typically remains hamstrung, many nations are conducting research with the goal of bringing back large events. France is planning to conduct experimental stadium concerts in Paris and Marseille. So far, about 2000 students with no underlying health risks have been enlisted to attend two separate concerts in Marseille organised by the French National Institute of Health and Medical Research. Attendees will be tested the day before the event, but not told their result to allow for the presence of infected individuals. Concertgoers will wear surgical grade N95 masks and be required to socially distance. The goal is to look at the transmission rates of infected people when safety measures are in place. Attendees will be tested for the two weeks after the event. The results will also be compared with a control group of 1000 people who won’t be at either concert.

4-7-21 Why the UK changed covid-19 AstraZeneca vaccine advice for under-30s
On 7 April, the UK effectively restricted use of the Oxford/AstraZeneca covid-19 vaccine to people aged 30 and over because of the risk of a rare blood clot syndrome. But other European countries and Canada have broader restrictions, with higher age cut-offs. Why are the regulations different, and what are the implications for vaccine roll-out in the UK? What are the safety concerns over the Oxford/AstraZeneca vaccine? UK and European medicines regulators have been reviewing a small number of people who developed blood clots linked with low levels of platelets – small particles in the blood that normally help in clotting – soon after having the Oxford/AstraZeneca vaccine. Both have now concluded that the clots are possibly caused by the vaccine, although they say the benefits of vaccination for most people outweigh the risks. How should people under 30 weigh the benefits and drawbacks? For healthy people under 30, the health risks from catching covid-19 are low, but there may be a slightly higher rate of the blood clot condition in younger people. So, the UK Joint Committee on Vaccination and Immunisation (JCVI) has said the risk-benefit equation is “more finely balanced” for this group. That means that for people under 30, the chance of the vaccine causing the clotting reaction is a little greater than the risk of severe illness from covid-19. Why are other countries setting the age limit higher? Canada and France have restricted the Oxford/AstraZeneca jab to people 55 and over, while Germany has set the bar at 60, and Iceland 70. These countries seem to have taken a more cautious, broad-brush approach, reasoning that the blood clots have generally been seen in middle-aged people so the vaccine should be withheld below a certain age until we know more. The JCVI, by contrast, today announced results of a detailed analysis, comparing the risk of the suspicious blood clots with the risk of getting badly ill from covid-19 for every age group in 10-year bands. This is why the committee set the age limit at 30.

4-5-21 New depictions of ancient hominids aim to overcome artistic biases
Reconstructions based on intuition can distort views of what extinct species looked like. Depictions of extinct human ancestors and cousins are often more art than science. Take, for example, two reconstructions of the Taung child, a 2.8-million-year-old Australopithecus africanus skull discovered in South Africa in 1924. One version, made using a sculptor’s intuition, appears more apelike. A second version, made while working alongside a scientist, appears more humanlike. Now, the researchers that produced the dueling images are attempting to remove some of this subjectivity by introducing standards that may give more accurate and reproducible portraits of species known only from fossilized bone. The team points out some of the flaws in facial reconstructions of ancient hominids — and the social and ethical implications misleading portraits may have — in a report published February 26 in Frontiers in Ecology and Evolution. Getting the depictions right matters, says Rui Diogo, a biological anthropologist at Howard University in Washington, D.C. When museumgoers see artists’ renditions of Neandertals or extinct hominids, visitors often don’t realize how much bias creeps into the work. “They think it is reality,” he says. And that can skew people’s views and reinforce existing prejudices of present-day people. For instance, reconstructions of multiple extinct hominids in the Smithsonian National Museum of Natural History in Washington, D.C., portray skin getting lighter and lighter in color as species became more and more bipedal. “But there is zero evidence to say the skin was whiter,” Diogo says. Such a depiction might give the mistaken impression that people with lighter skin are more evolved. Artists’ depictions can also give erroneous views of human evolution and extinct species’ intelligence and behavior, says Diogo’s coauthor Ryan Campbell, an anatomical scientist and physical anthropologist at the University of Adelaide in Australia. For instance, Neandertals are often portrayed as having matted, dirty hair. “It’s as if there is a bias toward portraying our ancestors as if they were stupid and didn’t have hygiene,” he says.

4-5-21 Stingrays in the Amazon were stranded there by the Caribbean Sea
The web of waterways draining out of tropical regions of South America is home to dozens of species of freshwater stingrays. The fish evolved from seagoing ancestors, but exactly how they got inland has always been unclear. Now it seems they were carried by the Caribbean Sea reaching deep into the continent millions of years ago. Central and South America are home to about 20 per cent of the world’s total fish species, says João Pedro Fontenelle at the University of Toronto in Canada. Intrigued by what could be responsible for this biodiversity, Fontenelle and his colleagues looked to the evolutionary history of river stingrays, which are only found in South America. There are 38 species, most with spots or marble patterns, and they range in size from 25 centimetres to more than a metre across. The stingrays are also the only exclusively freshwater lineage of shark or ray alive today. The researchers analysed DNA from 350 individual stingrays across 35 different species. By comparing genetic differences between species, they determined how the stingrays split into many species over time, giving insight into where and when they first left the sea. Fontenelle and his team estimate that the river stingrays diverged from their ocean relatives around 26 million years ago, between the Oligocene and Miocene epochs, in the upper Amazon basin. Back then, this area looked quite different from the dense rainforest present today. “The sea level was higher than it is today and the Andes were not that high, and we had a nice lowland formation on the western portion of the Amazon,” says Fontenelle. “That allowed for the sea to come into the continent.” Fossil and chemical evidence in rock suggests the northwestern corner of South America was dominated by a vast, swampy sea for millions of years. Known as the Pebas wetlands, they may have stretched as far south as Argentina.

4-4-21 The nature photography project for London health care workers
Liz Hingley started the "Nature of Care" project 10 months ago to helps nurses and doctors in London cope with pandemic-induced stress and anxiety by teaching them nature photography skills. his project — "Nature of Care" — started with a dream. Not a figurative, hopes-for-a-better-world kind of dream, but the middle of the night, vivid, outlandish variety of dream. When British photographer Liz Hingley's sleep was interrupted during the first coronavirus lockdown in 2020, she dreamed that nurses and doctors came streaming out of London's big hospitals, all dressed in masks and protective gear and began embracing trees — hugging them. "They were kind of socially distanced, hugging their tree with their hazmat suits on or face masks," Hingley told The World's host, Marco Werman. Hingley could not get the images from her nature dream out of her mind. She described the visuals in her dream as visceral. The next morning, she felt like she had to do something about it. "In my mind, when I woke up, I was like, I have to make that picture," Hingley said. "And then, I obviously realized after a coffee that I probably wasn't able to make that picture. But then I translated it into this project that I've been running almost for 10 months now." Below, Hingley talks with The World about her photography project and how it has offered weary health care providers a fresh perspective on life. Marco Werman: So, you know a lot about photography and about the world that can open up to people. What did you set out to do then with health care providers, two of London's largest hospitals after you had this dream? Liz Hingley: I'm really lucky to live next to a place called Hampstead Heath, which is a huge, kind of green area, that was given to the city of London — to the people in the city of London — 150 years ago this year. And during that time, I was doing my sort of one-hour lockdown exercise and walking on the Heath and so aware of what a healing resource this place was for me and for so many people during that really confusing time. And there's an area on the Heath where there's two of London's largest hospitals to either side of the city. I just kind of called them up cold and said, can I run some photography walks on the Heath for any stuff? And wonderfully, both hospitals responded positively. And I had no idea what the uptake would be, but it was kind of overwhelming. So, just to be clear, you kind of gave them the training and then they went out with their cameras and started taking photographs. Yeah, I managed to convince Canon to sponsor me because I was keen that they should be free. And that also people should have the ability to learn a little bit of photography, but also make some really stunning images. And the aim of the project, it was to really take people away from the workplace and the crisis conditions in the hospital. And, allow them to connect with local nature that was just on their doorstep and develop a practice potentially using photography as seeing more deeply and reconnecting, in a way, just in lunch breaks and short periods. I didn't label it as therapy. One thing that stuck with me when I first contacted the hospitals was that the head of staff in the Whittington Hospital in London said that staff, particularly critical care staff — so those at the really at the front-line intensive care — really rarely seek help. But what they always look for and respond to is the chance to relax. So, for many people, I guess the experience is very difficult to put into words and to communicate to others who have no idea what the environment is like. But being out and walking and physically being constructive and doing something with your body and also producing something at the same time, can feel quite constructive in a way of processing and expressing without putting things into words.

4-3-21 Sounding the alarm: How noise hurts the heart
Scientists are uncovering new details about how what you hear stresses the cardiovascular system. n 2011, Germany's Frankfurt Airport — the country's busiest — unveiled its fourth runway. The addition sparked major protests, with demonstrators returning to the airport every Monday for years. "It's destroying my life," one protester told Reuters a year later. "Every time I go into my garden, all I can hear and see are planes right above." The new runway also channeled dozens of aircraft directly over the house of Thomas Münzel, a cardiologist at the University Medical Center of Mainz. "I have lived close to the German Autobahn and close to inner city train tracks," he says. "Aircraft noise is the most annoying by far." Münzel had read a 2009 World Health Organization report linking noise to heart problems, but evidence at the time was thin. Driven in part by concern for his own health, in 2011 he shifted the focus of his research to learn more. Exposure to loud noise has long been linked with hearing loss. But the ruckus of planes and cars takes a toll beyond the ears: Traffic noise has been flagged as a major physiological stressor, second to air pollution and on roughly equal footing with exposure to secondhand smoke and radon. In the last decade, a growing body of research more directly links air and road traffic noise to a heightened risk for a number of cardiovascular ailments — and scientists are beginning to pinpoint the mechanisms at play. Evidence of noise's physiological effects — whether on cells and organs or entire populations — "is really coming together and painting a picture of the problem," says Mathias Basner, a psychiatrist and epidemiologist at the University of Pennsylvania and president of the International Commission on the Biological Effects of Noise. Yet, he adds, few people are aware of the severity of what his colleagues refer to as a "silent killer." Estimates suggest that roughly a third of Europeans and Americans are regularly exposed to unhealthy levels of noise, typically defined as starting around 70 to 80 decibels. For comparison, normal conversation is typically about 60 dB, cars and trucks range around 70 to 90 dB, and sirens and airplanes can reach 120 dB or more. Numerous studies link chronic exposure to such environmental noise to an increased risk of heart-related troubles. People living near the Frankfurt Airport, for example, have as much as a 7 percent higher risk of stroke than those living in similar but quieter neighborhoods, according to a 2018 study in Noise & Health that investigated health data of more than 1 million people. An analysis of nearly 25,000 cardiovascular deaths between 2000 and 2015 among people living near Switzerland's Zurich Airport saw significant increases in nighttime mortality after airplane flyovers, especially among women, a team reported last year in the European Heart Journal. As researchers probe the physiology underlying noise's cardiovascular consequences, they are zeroing in on a culprit: dramatic changes to the endothelium, the inner lining of arteries and blood vessels. This lining can go from a healthy state to one that's "activated," and inflamed, with potentially serious ramifications. The path from noise to blood vessels goes something like this: When sound reaches the brain, it activates two important regions: the auditory cortex, which interprets noise, and the amygdala, which manages emotional responses to it. As noise gets louder, and especially during sleep, the amygdala activates the body's flight-or-fight response — even if the person isn't aware of it.

4-3-21 Dinosaur-killing asteroid strike gave rise to Amazon rainforest
The asteroid impact that killed off the dinosaurs gave birth to our planet's tropical rainforests, a study suggests. Researchers used fossil pollen and leaves from Colombia to investigate how the impact changed South American tropical forests. After the 12km-wide space rock struck Earth 66 million years ago, the type of vegetation that made up these forests changed drastically. The team has outlined its findings in the prestigious journal Science. Co-author Dr Mónica Carvalho, from the Smithsonian Tropical Research Institution in Panama, said: "Our team examined over 50,000 fossil pollen records and more than 6,000 leaf fossils from before and after the impact." They found that cone-bearing plants called conifers and ferns were common before the huge asteroid struck what is now the Yucatan Peninsula in Mexico. But after the devastating impact, plant diversity declined by roughly 45% and extinctions were widespread, particularly among seed-bearing plants. While the forests recovered over the next six million years, angiosperms, or flowering plants, came to dominate them. The structure of tropical forests also changed as a result of this transition. During the late Cretaceous Period, when the dinosaurs were still alive, the trees that made up the forests were widely-spaced. The top parts did not overlap, leaving open sunlit areas on the forest floor. But post-impact, forests developed a thick canopy that allowed much less light to reach the ground. So how did the impact transform the sparse, conifer-rich tropical forests of the dinosaur age into the rainforests of today, with their towering trees dotted with multi-coloured blossoms and orchids? Based on their analysis of the pollen and leaves, the researchers propose three different explanations. Firstly, dinosaurs could have kept the forest from growing too dense by feeding on and trampling plants growing in the lower levels of the forest. A second explanation is that falling ash from the impact enriched soils throughout the tropics, giving an advantage to faster-growing flowering plants. The third explanation is that the preferential extinction of conifer species created an opportunity for flowering plants to take over.

4-2-21 Bronze Age dogs ate little meat and had to feed on cereals instead
Many early domestic dogs ate almost no meat. Dogs living around 3000 years ago in what is now Spain were instead fed cereals, such as millet, by their owners. Although the diet may reflect the fact that meat was relatively scarce among human societies at the time, feeding dogs with cereals could have been advantageous, says Silvia Albizuri at the University of Barcelona in Spain. It may have been a way to ensure the dogs had plenty of energy for the strenuous work of herding and guarding livestock, she says, particularly since these dogs “were not pets as we conceive them nowadays”. Dogs were domesticated from wolves in Europe and Asia within the past 40,000 years. Wolves are carnivores, getting most of their nutrition from meat. Albizuri and her colleagues studied the remains of 36 dogs from Can Roqueta, an archaeological site near Barcelona. It lies on a plain near the coast and was inhabited from the Stone Age onwards. The dogs lived in the Bronze Age and Iron Age, between 1300 and 550 BC, and had been buried in pits. The researchers obtained protein from the dogs’ bones and focused on the carbon and nitrogen atoms in the samples, each of which exist in two forms called isotopes. Different foods have varying ratios of carbon and nitrogen isotopes, and this influences the makeup of the protein – so studying the isotopes in the protein gives an indication of what the animals ate. The dogs’ diets differed considerably. While nine of them ate plenty of meat and 10 were omnivorous, the rest ate mostly plants – and some had isotope ratios that could barely be distinguished from those of the cattle they once guarded. The finding adds to the evidence that many early domestic dogs ate little meat, says Albizuri. This trend began with the advent of farming. “When human societies began to domesticate plants during the Neolithic period, hunting decreased and the human diet was based mainly on vegetables,” she says. “Dogs began to be fed on plants, mainly cereals.”

4-2-21 The dinosaur-killing asteroid impact radically altered Earth’s tropical forests
Sun-laden, open-canopied forests were transformed into the dark, dense ones seen today. The day before a giant asteroid hit Earth 66 million years ago, a very different kind of rainforest thrived in what is now Colombia. Ferns unfurled and flowering shrubs bathed in the sunlight that streamed down through large gaps in the canopy between towering conifers. Then the bolide hit and everything changed (SN: 6/1/20). That impact not only set off a massive extinction event that wiped out more than 75 percent of life on Earth, but it also redefined Earth’s tropical rainforests, transforming them from sun-dappled, open-canopied forests into the dark, dense, lush, dripping forests of today’s Amazon, researchers report April 2 in Science. The researchers analyzed tens of thousands of fossils of pollen, spores and leaves, collected from 39 sites across Colombia, that were dated to between 70 million and 56 million years ago. The team then assessed overall forest plant diversity, dominant species and insect-plant interactions, and tracked how these factors shifted. Plant diversity declined by 45 percent in the immediate aftermath of the asteroid strike, the researchers found, and it took 6 million years before the rich diversity of the tropical rainforest rebounded. Even then, the forests were never the same. “A single historical accident changed the ecological and evolutionary trajectory of tropical rainforests,” says Carlos Jaramillo, a paleopalynologist — someone who studies ancient pollen — at the Smithsonian Tropical Research Institute in Panama City. “The forests that we have today are really the by-product of what happened 66 million years ago.” Just before the extinction event, tropical forests were a roughly 50-50 mix of angiosperms, or flowering trees and shrubs, and of other plant species such as conifers and ferns. “The competition for light was not that intense,” Jaramillo says. Afterward, ferns and conifers largely vanished, and angiosperms took over to make up about 90 percent of the plant species in the forest.

4-1-21 Asteroid that killed the dinosaurs gave birth to the Amazon rainforest
Today’s tropical rainforests came about because of the huge asteroid strike thought to have wiped out the dinosaurs. Before the asteroid hit the Yucatán peninsula in what is now Mexico, South America’s rainforests were made up of vastly different greenery than the abundance of flowering plants they now contain. “If you returned to the day before the meteorite fall, the forest would have an open canopy with a lot of ferns, many conifers and dinosaurs,” says Carlos Jaramillo at the Smithsonian Tropical Research Institute in Panama. “The forest we have today is the product of one event 66 million years ago.” Jaramillo and his colleagues analysed tens of thousands of samples of fossilised pollen and leaves found in northern South America that dated to the part of the Cretaceous period just before the asteroid hit, and just after the impact, in the Palaeocene epoch. They found that plant diversity declined by 45 per cent after the impact and took 6 million years to recover. Insect bites on fossilised leaves showed that insect diversity also took a nosedive. The rainforests of South America changed in the aftermath of the catastrophe. Most of the cone-bearing plants and ferns disappeared, and the rainforests became dominated by flowering plants called angiosperms. A thick canopy allowed only a little light to reach the ground. “I think the number one lesson here is unpredictability,” says Ellen Currano at the University of Wyoming. “When you have these major perturbations, they change the rules of the whole ecosystem.” Jaramillo and his colleagues suggest there are several reasons why the asteroid may have caused this major change. For one, the impact probably killed most of the large, herbivorous dinosaurs that once trampled down and ate the lower levels of the forests.

4-1-21 Animal culture is so common that even fish and flies have it
Culture was once thought to be restricted to humans. But we are discovering more and more examples in animals. In a paper reviewing evidence from several earlier studies that is published in Science this week, zoologist Andrew Whiten at the University of St Andrews, UK, writes that there has been “an explosion of discoveries” showing that animal culture is far more widespread and diverse than we imagined. New Scientist quizzed him about the work. Michael Le Page: Many readers will know that apes and whales have culture, such as tool use in chimpanzees, but you say that even insects have it. Andrew Whiten: That is the big surprise. The evidence was really just published in the last few years. So some of us are still reeling from that and thinking, “Well, wow, culture is everywhere.” It’s the reach of animal culture across an increasing range of species that’s one of the main points of my paper. Can you give an example of insect culture? There’s good evidence for what’s called mate choice copying in fruit flies. So if female fruit flies watch a male who’s been dusted green by experimenters mate with a female, later on, if given a choice, those females will prefer green-dusted males. The virgin females are learning, “If all the girls like this kind of chap, he must be a good one to go for.” The reason that you can talk about cultural transmission is that if other females watch those females mating, they inherit that same bias, and so on. It is like an incipient tradition. In bumblebees there are examples of particular foraging techniques that again pass from bumblebee to bumblebee to bumblebee. What exactly do researchers mean by animal culture? It is basically behaviour that is passed from one individual to another, spreads across a group and becomes a group characteristic. It may be passed down many generations.

4-1-21 4 takeaways from the WHO’s report on the origins of the coronavirus
The leading hypothesis is it spread to people from bats via a yet-to-be-identified animal. A new World Health Organization report investigating the origins of the coronavirus has raised more questions than answers for how — and where — the virus that exploded into a global pandemic emerged. The report, released March 30, tallies where the evidence currently points: The virus, called SARS-CoV-2, probably jumped to people from bats through another animal; it likely did not come from a lab. But officials can’t yet prove — or rule out — any scenario. And questions about just how much access to potential evidence an international team of experts had on their 28-day trip to Wuhan, China, in January and February has cast a shadow on the findings. On that trip, 17 experts with the WHO teamed up with 17 Chinese scientists to assess four potential scenarios for the origins of the coronavirus. The two leading scenarios, the team concluded, are transmission of the virus to people either directly from bats or, more likely, via an intermediate animal like a civet or raccoon dog. A third possibility is the virus got to people through contaminated frozen food products, which the team considers less likely but says merits further investigation. The last scenario — that the virus began spreading among people following a lab accident — is “extremely unlikely,” the researchers wrote. In a joint statement on March 30, 14 countries including the United States expressed concern that the WHO team was delayed and didn’t have access to original data and samples from people and animals. That reaction comes amid reports that the Chinese government had a hand in the mission, controlling the sites the team accessed during the visit and the report’s wording. “Scientific missions like these should be able to do their work under conditions that produce independent and objective recommendations and findings,” the countries wrote in the statement.

4-1-21 Pfizer says its COVID-19 vaccine has 100 percent efficacy in young people
None of the vaccinated 12- to 15-year-olds had symptoms and the shot’s side effects were mild. Pfizer and BioNTech’s COVID-19 vaccine proved highly effective in adults. Now it appears to work well in younger people too. In a Phase III clinical trial of 12- to 15-year-olds, participants who received the shot developed higher levels of antibodies to the coronavirus on average compared with vaccinated 16- to 25-year-olds from a previous trial (SN: 11/18/20). And those antibody levels make for a vaccine with high efficacy. None of the 1,131 vaccinated teens developed COVID-19 symptoms. There were 18 cases among the 1,129 youths in the unvaccinated group, Pfizer reported in a March 31 news release. That 100 percent efficacy, based on a small number of cases overall, could decrease a bit as the trial continues because additional cases might pop up. Still, the results point to a vaccine that works well in adolescents. The news is “astounding and very exciting,” Colleen Kelley, an infectious diseases physician at Emory University in Atlanta who helped lead a trial of Moderna’s COVID-19 vaccine, said in a call with reporters. Though Pfizer has not yet released all the data from the trial, protecting adolescents “will go a long way to end the pandemic,” she said. That’s because kids younger than 12 appear to be less likely than older kids to get infected with the coronavirus and pass it on to others. The shot’s side effects in the 12- to 15-year-olds were similar to those seen in the 16- to 25-year-old age group, the company said. The most common side effect in the older participants was pain at the injection site, followed by fatigue and headache. Pfizer plans to submit the data to the U.S. Food and Drug Administration, as well as the European Medicines Agency, as soon as possible to ask that its emergency use authorizations be altered so that vaccinations can be expanded to those 12 and older.

4-1-21 Frog skin cells turned themselves into living machines
Newly created ‘xenobots’ swim and move particles around in their environment. Using blobs of skin cells from frog embryos, scientists have grown creatures unlike anything else on Earth, a new study reports. These microscopic “living machines” can swim, sweep up debris and heal themselves after a gash. Scientists often strive to understand the world as it exists, says Jacob Foster, a collective intelligence researcher at UCLA not involved with this research. But the new study, published March 31 in Science Robotics, is part of a “liberating moment in the history of science,” Foster says. “A reorientation towards what is possible.” In a way, the bots were self-made. Scientists removed small clumps of skin stem cells from frog embryos, to see what these cells would do on their own. Separated from their usual spots in a growing frog embryo, the cells organized themselves into balls and grew. About three days later, the clusters, called xenobots, began to swim. Normally, hairlike structures called cilia on frog skin repel pathogens and spread mucus around. But on the xenobots, cilia allowed them to motor around. That surprising development “is a great example of life reusing what’s at hand,” says study coauthor Michael Levin, a biologist at Tufts University in Medford, Mass. And that process happens fast. “This isn’t some sort of effect where evolution has found a new use over hundreds of thousands of years,” Levin says. “This happens in front of your eyes within two or three days.” Xenobots have no nerve cells and no brains. Yet xenobots — each about half a millimeter wide — can swim through very thin tubes and traverse curvy mazes. When put into an arena littered with small particles of iron oxide, the xenobots can sweep the debris into piles. Xenobots can even heal themselves; after being cut, the bots zipper themselves back into their spherical shapes.

4-1-21 Stone Age culture bloomed inland, not just along Africa’s coasts
Excavations at a rock-shelter inhabited 105,000 years ago turned up possibly symbolic crystals. Africa’s southern Kalahari Desert is not typically regarded as a hotbed of Stone Age innovations. And yet human culture blossomed there around 105,000 years ago, back when it was green, researchers say. Calcite crystals and other finds at a South African rock-shelter more than 600 kilometers from the nearest shoreline reflect cultural behaviors on a par with those previously reported for ancient humans living on or near South Africa’s coast, researchers report March 31 in Nature. Those coastal sites date to between roughly 125,000 and 70,000 years ago, including one where locals used tools to make paint out of pigment around 100,000 years ago (SN: 10/13/11). Given the scarcity of human sites from that time period, it’s hard to know whether cultural innovations emerged independently in groups spread across southern Africa or originated in one particular region before being adopted elsewhere. But the new discoveries fit a scenario in which “the emergence of Homo sapiens involved the interaction of many different populations across Africa,” says archaeologist Jayne Wilkins of Griffith University in Nathan, Australia. “And that included the Kalahari Desert.” Excavations at Ga-Mohana Hill North Rockshelter, or GHN, uncovered an ancient sediment layer containing 42 burned ostrich eggshell fragments and 22 palm-sized or smaller calcite crystals, Wilkins and her colleagues report. Like some African hunter-gatherer groups today, ancient people at GHN may have cut holes out of ostrich eggshells to create water containers, the researchers say. Geologic studies indicated that enough rain once fell over the southern Kalahari Desert to have produced year-round water sources for ancient GHN people.

86 Evolution News Articles
for April 2021

Evolution News Articles for March 2021