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125 Evolution News Articles
for March 2020
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3-31-20 Rock peeling off continents may have triggered biggest mass extinction
The largest known mass extinction may have been triggered by events deep inside Earth. Hundreds of millions of years ago, when the continents collided to form a single supercontinent, huge amounts of material may have detached from their undersides, causing hot molten rock to rise up and trigger enormous volcanic eruptions. There is strong evidence that massive volcanic eruptions were responsible for the Permian extinction 252 million years ago, which wiped out at least 80 per cent of species. These eruptions heated up the climate and caused the oceans to stagnate. But we don’t know what caused them. One possibility is that deep inside the planet, in the semi-molten mantle, a plume of unusually hot magma rose up and broke through the crust. Such plumes are thought to exist in the modern day: one under the Atlantic Ocean is believed to have created Iceland. However, according to Chen Zhang at the China University of Petroleum in Beijing and his colleagues, it isn’t clear whether a plume could release enough carbon dioxide to cause the climate changes that would have caused a mass extinction. Instead, they have proposed another possibility. The team studied crystals called zircons from rocks taken from the Central Asian Orogenic Belt – a region that now stretches from the Ural mountains to the Pacific Ocean. The rocks are from volcanic eruptions millions of years ago. By studying their chemical make-up, the team could tell how hot the magma the rocks formed from was, which points to the source of the eruption. There were two periods when volcanoes erupted unusually hot magma, the team found. One was about 252 million years ago, the time of the Permian extinction. The other was about 443 million years ago: when the Ordovician-Silurian mass extinction occurred.

3-31-20 Blood test shows promise for detecting the deadliest cancers early
A blood test developed and checked using blood samples from 4000 people can accurately detect more than 50 cancer types, often before any symptoms appear. It was most accurate at identifying 12 especially dangerous types, including pancreatic cancers that are usually diagnosed only at a very late stage. Many groups around the world are trying to develop blood tests for cancer, often referred to as “liquid biopsies”. Michael Seiden at US Oncology, a company involved in cancer care, and his team explored several ways of testing for cancer based on sequencing the DNA that dying cells release into the bloodstream. The team found that looking at methylation patterns at around a million sites was the most promising. Methyl groups are chemical tags added to inactive genes by cells, and cancer cells have abnormal methylation patterns. Next, the team trained a machine learning system on blood samples from 1500 people with untreated cancer and 1500 with no cancer diagnoses. They then used the system to analyse 650 blood samples from people with cancer and 610 without. The machine learning system had a specificity of 99.3 per cent, meaning 0.7 per cent of people were wrongly identified as having cancer when they did not. “Specificity is extremely important because you don’t want to raise false alarm in people who are well,” says Seiden. The true positive rate – the proportion of cancers detected – varied depending on how advanced the cancers were. For the 12 most deadly cancers, the true positive rate was 39 per cent in stage I, 69 per cent in stage II, 83 per cent in stage III and 92 per cent in stage IV. For all types, the corresponding rates were 18 per cent, 43 per cent, 81 per cent and 93 per cent. The test is now being trialled in a larger group of people.

3-31-20 Thomas Becket: Alpine ice sheds light on medieval murder
Ancient air pollution, trapped in ice, reveals new details about life and death in 12th Century Britain. In a study, scientists have found traces of lead, transported on the winds from British mines that operated in the late 1100s. Air pollution from lead in this time period was as bad as during the industrial revolution centuries later. The pollution also sheds light on a notorious murder of the medieval era; the killing of Thomas Becket. The assassination of the Archbishop of Canterbury, Thomas Becket, in 1170 in his cathedral was a gruesome event that made headlines all over Europe. The King, Henry II, and Becket were once very close - Becket had been Henry's chancellor before he was made Archbishop. Henry believed the appointment would allow the crown to gain control over the rich, powerful and relatively independent church. Becket, though, had other plans. Henry's growing irritation with his Archbishop led the King to reportedly utter the infamous phrase: "Will no one rid me of this turbulent priest?" Unfortunately for Becket, a group of knights loyal to the King decided to make Henry's wish come true. Becket was beheaded in a brutal attack at Canterbury cathedral on 29 December 1170. Now scientists have found physical evidence of the impact of the dispute between Henry and Becket in a 72-metre-long ice core, retrieved from the Colle Gnifetti glacier in the Swiss-Italian Alps. In the same way that trees detail their growth in annual rings, so glaciers compact a record of the chemical composition of the air, trapped in bubbles in the yearly build-up of ice. Analysing the 800 year-old ice using a highly sensitive laser, the scientists were able to see a huge surge in lead in the air and dust captured in the 12th century. Atmospheric modelling showed that the element was carried by winds from the north west, across the UK, where lead mining and smelting was booming in the late 1100s.

3-30-20 Soya protein can help make lab-grown beef with the texture of meat
Lab-grown “beef” is being made by culturing cow muscle cells within a spongy scaffold of soya bean protein. Prototypes of this cultured meat have passed initial taste tests, says developer Shulamit Levenberg at Aleph Farms in Ashdod, Israel. The idea behind cultured beef is that it could be as tasty as real meat without any animals having to be killed. It may also be better for the environment, although this isn’t clear. Cultured meat development has taken off in the past few years, with about 50 companies now attempting to perfect a recipe. A few have got to the stage of creating prototype samples for tasting, but nothing is yet on offer in shops or restaurants. Aside from the high cost of growing biological tissue in a dish, one problem is that meat doesn’t just consist of muscle cells. In animal flesh, these cells sit within a supporting scaffold of extracellular protein, which has to be mimicked to give the product a similar texture to real beef. “You want to recreate the tissue as it is in the animal,” says Elliot Swartz at the Good Food Institute in Washington DC. At the moment, cultured meat uses a scaffold that is often derived from beef gelatin, a collagen protein obtained by boiling carcasses from slaughterhouses. This is a problem if vegetarians are your target market. Now Aleph Farms may have found an alternative: textured soya protein, which is a by-product of soya-bean oil manufacture and is already used in many vegetarian substitutes for meat. The team grew cow muscle and blood vessel cells on a spongy scaffold of soya protein, then baked or fried small morsels of the fake meat. Three volunteers who tasted the cultured meat said it replicated “the sensation and texture of a meat bite”, the researchers said.

3-29-20 Social distancing comes with psychological fallout
Experts warn prolonged isolation during the pandemic may worsen or trigger mental health problems. As increasingly stringent measures to keep people apart are put in place to slow the spread of the coronavirus, mental health experts are warning that losing everyday social connections comes with psychological costs. And those costs could go up the longer such measures drag on. In response to the accelerating pandemic, a growing number of states have banned all nonessential activities and asked residents to stay home. Across the country, colleges and offices have gone entirely online, schools and restaurants are closed and nursing homes are barring visitors. Such social distancing can stop, or at least slow, the spread of COVID-19, the disease caused by the new coronavirus (SN: 3/13/20). But “for some people, a lack of social connectedness feels as impactful as not eating,” says Joshua Morganstein, a psychiatrist and disaster mental health expert at the Uniformed Services University in Bethesda, Md. Research on the psychological toll of social distancing during epidemics is limited. But a review in the March 14 Lancet provides some clues. Researchers evaluated 24 studies looking at the psychological outcomes of people who were quarantined, an extreme form of social distancing, during outbreaks of SARS, H1N1 flu, Ebola and other infectious diseases since the early 2000s. Many quarantined individuals experienced both short- and long-term mental health problems, including stress, insomnia, emotional exhaustion and substance abuse. For instance, one study compared quarantined versus non-quarantined individuals during an equine influenza outbreak. Of 2,760 quarantined people, 34 percent, or 938 individuals, reported high levels of psychological distress, which can indicate mental health problems such as anxiety and depression, during the outbreak compared with 12 percent of non-quarantined individuals.

3-29-20 Once coronavirus infects a human body, what happens next?
Everything you need to know about coronavirus. Once the coronavirus infects a human body, what happens? Here's everything you need to know:

  1. What exactly is the coronavirus? A virus is a parasitic microbe, so tiny that hundreds of millions could fit on the head of a pin. It's a coiled strand of genetic material embedded in a protective coat of protein that invades healthy human cells and essentially hijacks them, using the cell's genetic machinery to duplicate itself.
  2. How does the virus infect people? Those infected with the coronavirus soon carry trillions of microbes; their saliva teems with them. When they cough, sneeze, talk, or even just breathe heavily they emit droplets laden with germs — a sneeze can launch 40,000 droplets.
  3. What happens then? Once the virus attaches itself to a healthy cell, it sets about its work, fusing its membrane with the cell membrane, releasing its core RNA strand and cranking out copies. In effect, said William Schaffner, an infectious disease expert at Vanderbilt University, the intruders order the inflamed cell, "'Don't do your usual job. Your job is now to help me multiply.'"
  4. What happens in the lungs? At this point, the virus begins to attack cells lining the lungs, inflaming the tiny sacs that send oxygen to the blood and remove carbon dioxide. Breaths become shorter and more difficult. As cells die, the lungs become clogged with fluid and debris and can develop secondary infections; this is pneumonia.
  5. What is a cytokine storm? Cytokines are chemicals released as an alarm signal when the body detects dead cell fragments indicating that an attack is underway. These chemicals rally the immune system and set off a battle to expel the invader. In a cytokine storm, the immune response spins out of control and starts attacking healthy cells as well as damaged ones.
  6. The role of age and gender: Why does the coronavirus cause only mild symptoms in some while overwhelming others? Some factors are clear — others, scientists are working to understand. The most obvious factor is age, with elderly patients accounting for the majority of fatalities and the roughly 5 percent of cases that become critical. The reason is that the immune system becomes considerably less effective as people grow older.

3-28-20 How antibody tests work and could help fight the coronavirus
Questions about the tests’ accuracy still need to be answered. The United Kingdom has ordered 3.5 million antibody tests, which would show whether someone has been exposed to COVID-19. Such tests, which just take a drop of blood, could help reveal people who have been exposed to the virus and are now likely immune, meaning they could go back to work and resume their normal lives. Antibodies are proteins that the body’s white blood cells produce to fight an infection. They bind to a virus, preventing it from infecting a cell, and can remain in blood long after the infection clears. Antibody tests are commonly used to test for exposure to other viruses. Science News spoke with David Weiner, director of the Vaccine and Immunotherapy Center at the Wistar Institute in Philadelphia, and Charles Cairns, dean of the Drexel University College of Medicine, about how antibody tests work and what are some of the challenges of developing the tests. Antibody tests look to see if someone has been exposed to a specific antigen, like a virus. The British tests are designed to work in one of two ways. They either detect human antibodies in blood using an antigen designed to be similar to a feature of the virus. Or conversely, the test detects the virus in blood using a [human-made] antibody designed to trap the virus. Diagnostic tests are using RT-PCR tests (SN: 3/6/20). You take a nasal swab (or sputum sample) that identifies the specific viral RNA from the COVID-19 virus. It’s the gold standard to see if you are actively infected. The antibody tests are quick — a prick of blood and you get a yes/no answer. You’ve had COVID-19 or you haven’t. People who have recovered won’t have RT-PCR positive tests, as they’ve already cleared the virus. Those who are recovered, those antibodies protect them from reinfection. (It’s still unclear, however, how long that immunity might last.)

3-27-20 Does a high viral load or infectious dose make covid-19 worse?
Does being exposed to more coronavirus particles mean you will develop a more severe illness? Rumours circulating on social media suggest that hospital workers or their household members exposed to a higher “viral load” become sicker than the general population. But emerging research indicates the relationship between infection and covid-19 severity may be more complex – and differ from that of other respiratory illnesses. The average number of viral particles needed to establish an infection is known as the infectious dose. We don’t know what this is for covid-19 yet, but given how rapidly the disease is spreading, it is likely to be relatively low – in the region of a few hundred or thousand particles, says Willem van Schaik at the University of Birmingham, UK. Viral load, on the other hand, relates to the number of viral particles being carried by an infected individual and shed into their environment. “The viral load is a measure of how bright the fire is burning in an individual, whereas the infectious dose is the spark that gets that fire going,” says Edward Parker at the London School of Hygiene and Tropical Medicine. If you have a high viral load, you are more likely to infect other people, because you may be shedding more virus particles. However, in the case of covid-19, it doesn’t necessarily follow that a higher viral load will lead to more severe symptoms. For instance, health workers investigating the covid-19 outbreak in the Lombardy region of Italy looked at more than 5,000 infected people and found no difference in viral load between those with symptoms and those without. They reached this conclusion after tracing people who had been in contact with someone known to be infected with the coronavirus and testing them to see if they were also infected.

3-27-20 Neandertals’ extensive seafood menu rivals that of ancient humans
Finds from a coastal cave in Portugal reveal repeated ocean foraging for this European hominid. Surf’s up, Neandertals. Our close evolutionary cousins obtained shellfish, crabs, fish and other marine munchies along Europe’s Atlantic coast with all the savvy and gusto of ancient humans who foraged along southern Africa’s shoreline, say archaeologist João Zilhão of the University of Barcelona and his colleagues. Neandertals consumed a diverse menu of sea and land foods while occupying Figueira Brava cave, on Portugal’s coast, for extended periods between around 106,000 and 86,000 years ago, Zilhão’s group says. Excavations there show for the first time that Neandertals matched Stone Age Homo sapiens in their ability to exploit seafood rich in brain-enhancing fatty acids, the scientists report in the March 27 Science. This discovery adds to controversial evidence that Neandertals engaged in various behaviors traditionally thought to have characterized only H. sapiens, such as creating cave art and elaborate personal ornaments (SN: 10/28/19; SN: 3/20/15). Extensive seaside activity at Figueira Brava also expands on preliminary evidence of Neandertal clamshell collecting on the beach and in shallow Mediterranean waters (SN: 1/15/20). Other excavations had suggested Neandertals occasionally gathered shellfish and hunted or scavenged sea animals starting around 110,000 years ago (SN: 9/22/08). But repeated bouts of Neandertal foraging at Figueira Brava over a roughly 20,000-year span point to coastal activity as extensive as that of H. sapiens who harvested shellfish at South Africa’s Pinnacle Point between 164,000 and 120,000 years ago, Zilhão says (SN: 7/29/11). Intensive shellfish collecting requires tracking of the tides and the seasons, “certainly one of the hallmarks of behavioral adaptability of early Neandertals [in Europe] and modern humans in South Africa,” says archaeologist Katerina Douka of the Max Planck Institute for the Science of Human History in Jena, Germany. She did not participate in the new study.

3-27-20 Fossils of a new dromaeosaur date to the end of the Age of Dinosaurs
Newly discovered species suggests these fierce predators were diversifying right up to the end. A wolf-sized warrior, kin to the fierce, feathered Velociraptor, prowled what is now New Mexico about 68 million years ago. Dineobellator notohesperus was a dromaeosaur, a group of swift, agile predators that is distantly related to the much larger Tyrannosaurus rex. The discovery of this new species suggests that dromaeosaurs were still diversifying, and even becoming better at pursuing prey, right up to the end of the Age of Dinosaurs, researchers say March 26 in Scientific Reports. That age came to an abrupt close at the end of the Cretaceous Period about 66 million years ago, when a mass extinction event wiped out all nonbird dinosaurs. A gap in the global fossil record for dromaeosaurs near the end of the Cretaceous had led some scientists to wonder whether the group was already in decline before the extinction, says Steven Jasinski, a paleontologist at the State Museum of Pennsylvania in Harrisburg (SN: 4/21/16). The new find suggests otherwise. Since 2008, Jasinski and his colleagues have recovered more than 20 fossilized pieces of the new species from the Bisti/De-Na-Zin Wilderness, a rapidly eroding region of barren badlands in northwestern New Mexico. Analyses of muscle attachment sites on the fossilized forelimbs suggest the dinosaur was unusually strong for a dromaeosaur, with a very tight grip in its hands and feet. That grip, Jasinski says, was likely stronger than that of its famous kinfolk, Velociraptor and Utahraptor, giving the new species extra weaponry in its pursuit of prey. Like many other dromaeosaurs, D. notohesperus had feathers, evidenced by the presence of quill nobs — bumps indicating where the feathers were attached — on its limbs (SN: 9/19/07). But, like Velociraptor, it probably used the feathers for purposes other than flight, Jasinski says, such as sexual selection, camouflage or added agility while on the hunt.

3-26-20 Neanderthals feasted on seafood and nuts according to fossil remains
Neanderthals dined on a menu of surf and turf with a sprinkling of pine nuts, an excavation of a coastal site in Portugal reveals. This is the first firm evidence that our extinct cousins relied on food from the sea, and their flexible diet is yet more proof that they behaved in remarkably similar ways to modern humans. The new dietary analysis comes from a site occupied by Neanderthals between 106,000 and 86,000 years ago in Figueira Brava, south of Lisbon. A painstaking excavation of fossil food remains, led by João Zilhão at the University of Barcelona, Spain, showed that the Neanderthals that lived there consumed a wide range of foods, dominated by seafood. “It’s a mixed diet,” says Zilhão. They were fisher-hunter-gatherers, collecting large amounts limpets, mussels and clams, as well as brown and spider crabs in particular, he says. “Crabs were the most important marine resource they exploited.” Fossil remains from the cave showed that fish, seal, dolphin, seabirds and land animals such as deer, horse, and wild goat were also on the menu. By contrast, Neanderthals living inland mainly hunted land animals such as mammoth, bison and woolly rhino. The team also found evidence of a thriving economy based on pine trees. “They used the wood for fuel and collected the pine cones, stored them, then consumed them as needed by roasting the cones and cracking the nuts to eat the kernel,” says Zilhão. Finding out more about marine-based meals of the Iberian Neanderthals is overturning our understanding of how the modern human species, Homo sapiens, developed. A diet rich in seafood is thought to have been crucial for the development of modern human cognition. Evidence for this idea comes from the caves at Pinnacle Point in South Africa, which shows that early modern humans ate marine foods as far back as 160,000 years ago.

3-26-20 Neanderthals ate sharks and dolphins
Neanderthals were eating fish, mussels and seals at a site in present-day Portugal, according to a new study. The research adds to mounting evidence that our evolutionary relatives may have relied on the sea for food just as much as ancient modern humans. For decades, the ability to gather food from the sea and from rivers was seen as something unique to our own species. Scientists found evidence for an intensive reliance on seafood at a Neanderthal site in southern Portugal. Neanderthals living between 106,000 and 86,000 years ago at the cave of Figueira Brava near Setubal were eating mussels, crab, fish - including sharks, eels and sea bream - seabirds, dolphins and seals. The research team, led by Dr João Zilhão from the University of Barcelona, Spain, found that marine food made up about 50% of the diet of the Figueira Brava Neanderthals. The other half came from terrestrial animals, such as deer, goats, horses, aurochs (ancient wild cattle) and tortoises. Some of the earliest known evidence for the exploitation of marine resources by modern humans (Homo sapiens) dates to around 160,000 years ago in southern Africa. A few researchers previously proposed a theory that the brain-boosting fatty acids seafood contributed to enhanced cognitive development in early modern humans. This, the theory goes, could help account for a period of marked invention and creativity that started among modern human populations in Africa around 200,000 years ago. It might also have assisted modern humans to outcompete other human groups such as the Neanderthals and Denisovans. But the researchers found that the Neanderthal inhabitants of Figueira Brava relied on the sea in a scale comparable to modern human groups living at a similar time in southern Africa. Commenting on the findings, Dr Matthew Pope, from the Institute of Archaeology at UCL, UK, said: "Zilhão and the team claim to have identified 'middens'. This is a shorthand for humanly created structures (piles, heaps, mounds) formed almost entirely of shell. "They are important as they suggest a systematic and organised behaviour, from collection to processing to discard."

3-26-20 Velociraptor relative had a much stronger grip than its cousins
A new species of carnivorous dinosaur related to velociraptors has been identified from 20 fossils, including bones and bone fragments, found in New Mexico. The discovery supports the theory that there was more species diversity than previously thought during the late Cretaceous period, just before non-avian dinosaurs went extinct. “I knew we had something distinct early on,” says Steven Jasinski at the State Museum of Pennsylvania. In 2008, Jasinski and his colleagues discovered fragments in the Bisti/De-na-zin Wilderness, New Mexico, that formed part of a claw. It looked like it belonged to a dromaeosaurid – the group of dinosaurs that includes velociraptors. Yet the claw was unusual. It was larger than average, and the position of scars that indicate where muscle would have been attached to the bone suggested that the dinosaur it belonged to had a much stronger grip than other known dromaeosaurids, says Jasinski. “We knew there was something there,” he says. “So we collected all the fragments we could and brought them back to the museum, and slowly started attempting to piece things back together.” Subsequent fossil collecting between 2008 and 2016 from the same 1-square-metre area gave the researchers enough material to complete the picture. The fossils came from a previously unknown species of dromaeosaurid dinosaur, now named Dineobellator notohesperus, which lived during the late Cretaceous period, about 70 million years ago. The dinosaur’s name is derived from the Navajo word Diné – a name used by members of the Navajo Nation, which includes part of New Mexico, to refer to themselves and their culture – followed by the Latin suffix bellator, meaning warrior. Notohesperus comes from Greek words for south and western, in reference to the south-west of the US where the fossils were found.

3-26-20 Hepatitis C infection rates are being cut by testing and treatment
There is one deadly infection that we can beat: the virus that causes hepatitis C. This liver disease-causing virus was on a global rampage a decade ago, but is being pushed back in some countries by mass testing and treatment, according to new figures. Egypt, once the country with the highest prevalence of this virus, is on course to slash infection rates by 2020, eliminating hepatitis C as a public health threat as defined by the World Health Organization. In the UK, cases have fallen by two-thirds in one of the worst-affected groups, HIV-positive gay men. The trends are likely to be happening in other countries that employ this strategy too, says Lucy Garvey at St Mary’s Hospital in London. The hepatitis C virus, which can cause liver failure and cancer, is mainly passed on through sex or by drug users sharing needles. In the past it was also widely spread by healthcare staff reusing needles. Practical curative treatments arrived a few years ago, but the drugs were initially too costly for most people – one of the first cost $1000 a tablet. Cheap generic versions now exist. Egypt has led the way in their use. Until recently, one in 10 adults in the country had the virus, as a result of needles being reused during past mass treatment campaigns against parasitic worms. In 2018, the country began the voluntary screening of all adults with free tests and treatment. By last year, 80 per cent of the country had taken part and more than 2 million people had been treated. If trends continue, the infection rate is set to fall to below 0.5 per cent of the population this year, according to figures out this month in The New England Journal of Medicine. Some developed economies with low infection rates in the general population are targeting high-risk groups, such as people who are HIV-positive or who inject drugs – an approach called micro-elimination – by offering frequent testing.

3-26-20 Squid edit their genetic material in a uniquely weird place
The ability may help the animals make specialized proteins on the fly. Squid can edit their genetic information in a place scientists didn’t expect. Longfin inshore squid (Doryteuthis pealeii) are the first known animals that can tweak strings of RNA outside of a nerve cell’s nucleus. These genetic couriers, called messenger RNA, or mRNA, carry a cell’s blueprints for building proteins. All creatures make edits to RNA — including other types besides mRNA — and do so sparingly, based on limited studies in mammals and fruit flies. Those changes typically take place inside the nucleus and are then exported to the rest of the cell. The squids’ ability to make genetic edits in cytoplasm, the jellylike material that makes up much of a cell, may let the animals make adjustments to mRNAs on the fly. That skill could help squids produce proteins tailored to meet a cell’s needs and hone crucial cell processes, researchers report March 23 in Nucleic Acids Research. Knowing how the squids make the edits in nerve cells could help researchers hijack the technique to develop therapeutics for health conditions such as chronic pain by genetically editing cells that create inappropriate pain signals, says Joshua Rosenthal, a biologist at the Marine Biological Laboratory in Woods Hole, Mass. The method would be much like the DNA-editing technique CRISPR, but for RNA. In the new study, Rosenthal and colleagues first looked at where an mRNA-editing protein is found in squid nerve cells, or neurons. The team discovered that the protein, called ADAR2, is located in both the jellylike cytoplasm and the nucleus of squid neurons, a hint that the protein could edit mRNAs in both areas. The team then extracted cytoplasm from squid axons — the slender stalk of a neuron — “kind of like you’re squeezing toothpaste out of the tube,” Rosenthal says. ADAR2 extensively edited an mRNA within the cytoplasm siphoned from the axons, which help send electrical impulses along nerve cells, the researchers found.

3-26-20 New Guinea’s Neolithic period may have started without outside help
Artifacts counter the idea that cultural changes sparked by farming were imported from Asia. Signs of a cultural shift in toolmaking and lifestyles sparked by farming, previously found at ancient Asian and European sites, have surfaced for the first time on New Guinea. Excavations at a highland site called Waim produced relics of a cultural transition to village life, which played out on the remote island north of Australia around 5,050 to 4,200 years ago. Archaeologist Ben Shaw of the University of New South Wales in Sydney and colleagues report the findings March 25 in Science Advances. Agriculture on New Guinea originated in the island’s highlands an estimated 8,000 to 4,000 years ago. But corresponding cultural changes, such as living in villages and making elaborate ritual and symbolic objects, have often been assumed to have emerged only when Lapita farmers from Southeast Asia reached New Guinea around 3,000 years ago (SN: 9/2/15). In Asia and Europe, those cultural changes mark the beginning of the Neolithic period. The new finds suggest that a Neolithic period also independently developed in New Guinea. Key finds at Waim consist of a piece of a carved human or animal face that probably had symbolic meaning and two stone pestles bearing traces of yam, fruit and nut starches. Other discoveries include a stone cutting or chopping tool, a pigment-stained stone with deep incisions that may have been used to apply coloring to plant fibers and an iron-rich rock fragment that was likely struck with other stones to create sparks for igniting fires. Farming’s rise on New Guinea apparently inspired long-distance, seagoing trade, the scientists say. Chemical analysis of an unearthed chunk of obsidian — displaying marks created when someone hammered off sharp flakes — indicates it was imported from an island located at least 800 kilometers away.

3-26-20 Dino-killing asteroid choked whole world in dust within a few hours
It was the dust storm to end all dust storms. When a huge asteroid hit Earth 66 million years ago, triggering a mass extinction that wiped out the dinosaurs, it sent vast clouds of dust flying tens of kilometres up into the air. We now think these spread around the planet at speeds of up to 6 kilometres per second, cloaking it within hours. If anyone had watched from space, they would have seen our planet become swathed within just a few hours of the asteroid hitting, says Joanna Morgan at Imperial College London. “You’d see this dust cloud expanding from the impact site and everything getting covered.” The ensuing extinction wiped out all dinosaurs and many other species except for a few land animals, including a group called the archosaurs – these eventually gave rise to modern birds. Morgan and her co-author Natalia Artemieva at the Planetary Science Institute in Tucson, Arizona, first decided to simulate such a dust cloud around 2007. Developing the model and simulating the behaviour of the atmosphere and the rocks and dust in the ejecta was painstaking. “It’s taken over 10 years,” says Morgan. They were trying to solve a mystery about the event, which concerns a key piece of evidence for the asteroid impact: a layer of extraterrestrial material, about 3 millimetres thick, laid down in rocks from the time of the collision. Strangely, the layer is the same everywhere it is found in the world. “It’s a constant thickness with a constant composition,” says Morgan. That is odd. For example, when volcanoes erupt, the heaviest lumps of material land close by and only the lightest bits travel great distances. As a result, sites far away from the eruption have less material. “The layer thickness decreases with distance from the site,” says Morgan. The asteroid hit Earth near what is now Chicxulub on Mexico’s Yucatán peninsula, so there should be a thinner layer of material at sites far away from Mexico.

3-25-20 How long does coronavirus stay on surfaces and can they infect you?
As global cases of covid-19 continue to soar and people with symptoms are expected to be isolated from others, it is no surprise that a growing number of us flinch when we hear someone cough, even if they are 2 metres away – the minimum separation that health officials advise. Research conducted on the new coronavirus and others similar to it, such as SARS, suggest the virus can spread through particles in the air and via contaminated surfaces. How does this happen? Moreover, how long can the virus survive on surfaces and what can we do to protect ourselves? Covid-19 is a respiratory illness and is largely spread via droplets in the air, says John Lednicky, a virologist who studies coronaviruses at the University of Florida. These are typically expelled when an infected person coughs or sneezes. But speaking also releases droplets. The heavier of these will fall to the ground, but smaller, lighter particles can travel further and linger in the air, and are more likely to infect other people, says Lednicky. “You can inhale those, but they can also come into contact with your eyes,” he says. Even if you keep your distance, there’s a chance of coming into contact with a virus as you walk through a cloud of expelled particles, says Lednicky. It isn’t clear if this is the case with the new coronavirus, but other, similar viruses can spread this way, he says. There are other, even less pleasant, ways virus-laden particles can get into the air. The symptoms of the coronavirus can vary, but some people experience diarrhoea. “If you use a flush toilet, you create an aerosol full of infection,” says Lednicky. This effect is more pronounced than usual with diarrhoea, which can contaminate more of a toilet’s surface. The released aerosols can travel along plumbing and ventilation systems and end up moving through buildings and apartment blocks.

3-25-20 Eating too much salt seems to impair body's ability to fight bacteria
Eating too much salt may impair the body’s ability to fight bacterial infections, according to studies in mice and in 10 human volunteers. Christian Kurts at the University Hospital of Bonn in Germany and his team first showed that mice given a high salt diet were less able to fight kidney infections caused by E. coli and body-wide infections caused by Listeria monocytogenes, a common cause of food poisoning. “The bacteria caused more damage before the immune system got rid them,” says Kurts. Next, the team gave 10 healthy women and men who were 20 to 50 years old an extra 6 grams of salt a day on top of their normal diet, in the form of three tablets a day. After a week, some of their immune cells, called neutrophils, had a greatly impaired ability to engulf and kill bacteria compared with the same tests done on each individual before they took extra salt. The team didn’t examine the effect of high salt intake on the body’s ability to fight viral infections. The World Health Organization recommends that people eat no more than 5 grams of salt a day to avoid high blood pressure, which can cause strokes and heart disease. In the UK, people eat 8 grams on average, suggesting many consume as much or more than the volunteers in the study. The team thinks two mechanisms are involved. First, when we eat lots of salt, hormones are released to make the body excrete more salt. These include glucocorticoids that have the side effect of suppressing the immune system throughout the body. Second, there is a local effect in the kidney. Kurts found that urea accumulates in the kidney when salt levels are high, and that urea suppresses neutrophils.

3-25-20 A new wave of apps say they can improve your friendships – can they?
Always forgetting birthdays? Terrible at staying in touch? New tech promises to turn you into the best buddy ever. We put it to the test. IT’S 8.18 am on a Wednesday when my phone buzzes with a prompt to “Offer your knowledge to others”. The push notification also tells me that I have “three relationships to reach out to”, including, in brackets, the name of my sister, and “four new people” to “discover” – here it mentions someone I recently emailed for work. I ignore it, then click snooze on several other reminders to reach out to my friends. The message is from UpHabit, one of many apps that have launched in the past couple of years to help people better manage their relationships. They are based on customer relationship management software, or CRMs, which are now routinely used by companies for things like compiling customer data and offering up suggestions on how to retain business. These new apps, personal CRMs, offer similar services, but the relationships they help you “manage” are with your friends, family, colleagues and acquaintances. In an era when people tend to move house or job multiple times, making and neglecting relationships as they go, these tools promise to help us stay in touch – and be better, more thoughtful friends. Yet how many people can we genuinely stay connected to? And if I send a message to someone because an app prompted me to, is it less meaningful somehow than if I remember myself? To understand why so many personal CRMs, or PRMs, have popped up since 2018, what that says about our relationships and whether push notifications can really make us better friends, I gave a few a try. It didn’t go quite as I expected. If these kinds of apps sound tempting, you are currently spoiled for choice. From the least to the most inexplicably named, you can now download Ntwrk, UpHabit, Plum Contacts, Dex, Garden, Levitate, Monaru, Clay and Hippo.

3-25-20 Farming and art arose in New Guinea at same time as Europe and Asia
People on the island of New Guinea began farming, practising arts and crafts and making complex tools around the same time as their European and Asian counterparts. Agriculture emerged in different parts of the world around 10,000 years ago, when the climate became favourable for planting crops. In Europe and Asia, this spurred the development of complex cultures as more and more people started living together around farms. Archaeological records show that people in New Guinea began farming around the same time as their Eurasian counterparts, planting yams, bananas and other local crops. But until now, there hasn’t been convincing evidence that this kickstarted an equivalent cultural movement. Ben Shaw at the University of New South Wales in Australia was scouting for archaeological sites in Papua New Guinea, the eastern half of the island, in 2016 when residents of a village called Waim approached him to tell him they had found some “really weird-looking stone tools” and a stone carving of a human face with a bird on top that might be of interest. Shaw followed them back to Waim, which sits halfway up a steep mountain in Jiwaka Province. “I didn’t have a lot of time so I decided to just dig one hole before it got dark,” he says. “Halfway through that hole I found the bottom half of a beautifully shaped stone pestle – I was beside myself with excitement.” Shaw and his colleagues decided to conduct a proper excavation of the site. They uncovered a wealth of artefacts, including part of a stone carving of a face, two stone pestle fragments, a fire-lighting tool, an ochre-stained rock with cut marks, and axe fragments. Radiocarbon dating of charcoal buried with the artefacts revealed they were between 4200 to 5050 years old. The pestle fragments still had bits of yam, banana, sugarcane and nuts stuck to them, suggesting they were used to grind up food. The researchers learned that the ochre-stained rock was a traditional tool for dyeing organic fibres after showing it to people in Waim.

3-25-20 When will the coronavirus pandemic and social distancing end?
Up to two-thirds of a population needs immunity, via infection or vaccines, to stop COVID-19. As the gears of the modern world grind to a near halt, one question is likely on the mind of many: When will the coronavirus pandemic — and social distancing — end? No one knows for sure, but it’s probably not any time soon. Here’s what we do know about when it may be safe to come out of our homes and resume normal life. It will almost certainly take herd immunity to end the pandemic. Most experts say we’re past the point of containing the virus, like we did with SARS and MERS. That means that COVID-19 is here to stay, and the pandemic will end only with herd immunity. Herd immunity describes what proportion of a population has to be immune to a disease for the population as a whole to be protected from outbreaks. The exact threshold depends on the infectiousness of the disease, represented by the basic reproduction number, called R0 (pronounced “R naught”). When a new virus emerges, no one is immune. A highly transmissible virus, like the coronavirus behind the current pandemic, can spread like wildfire, quickly burning through the dry kindling of a totally naive population. But once enough people are immune, the virus runs into walls of immunity, and the pandemic peters out instead of raging ahead. Scientists call that the herd immunity threshold. Up to two-thirds of a population would need to be infected to reach that threshold. Current estimates put the coronavirus’s R0 between two or three, meaning anyone with COVID-19 tends, on average, to infect two or three other people. While this number can change based on our behavior, researchers estimate that the herd immunity threshold for COVID-19 is about one-third to two-thirds of any given population. Worldwide, that means anywhere from 2.5 billion to 5 billion people. Scientists aren’t yet sure how long people infected with COVID-19 remain immune, but so far it seems that they aren’t readily reinfected (SN: 3/4/20).

3-25-20 Can you catch the coronavirus twice? We don’t know yet
SAY you have caught covid-19 and recovered – are you now immune for life, or could you catch it again? We just don’t know yet. In February, reports emerged of a woman in Japan who had been given the all-clear after having covid-19 but then tested positive for the SARS-CoV-2 virus a second time. There have also been reports of a man in Japan testing positive after being given the all-clear, and anecdotal cases of second positives have emerged from China, too. This has raised fears that people may not develop immunity to the virus. This would mean that, until we have an effective vaccine, we could all experience repeated rounds of infection. But the science is still uncertain. “There is some anecdotal evidence of reinfections, but we really don’t know,” says Ira Longini at the University of Florida. It may be that the tests used were unreliable, which is a problem with tests for other respiratory viruses, says Jeffrey Shaman at Columbia University in New York. Early signs from small animal experiments are reassuring. A team from the Chinese Academy of Medical Sciences in Beijing exposed four rhesus macaques to the virus. A week later, all four were ill with covid-19-like symptoms and had high virus loads. Two weeks later, the macaques had recovered and were confirmed to have antibodies to the virus in their bloodstream. The researchers then tried to reinfect two of them but failed, which suggests the animals were immune (bioRxiv, doi.org/ggn8r8). “That finding is very encouraging, as it suggests that it is possible to induce protective immunity against the virus,” says Alfredo Garzino-Demo at the University of Maryland School of Medicine. But that doesn’t necessarily mean long-term immunity. There are other coronaviruses circulating among humans and although they induce immunity, this doesn’t last. “Some other viruses in the coronavirus family, such as those that cause common colds, tend to induce immunity that is relatively short-lived, at around three months,” says Peter Openshaw at Imperial College London.

3-25-20 How to fight infection by turning back your immune system's clock
Your immune system ages too, weakening as you get older and making you more susceptible to infections. Fortunately, we are discovering plenty of things you can do to turn back the clock and stay healthy. WASH your hands religiously for 20 seconds, sneeze into your elbow, avoid touching your face, stay 1 metre away from all other people and, as a last resort, self-quarantine for a week with only your emergency rations for company. If you want to avoid getting the new coronavirus, all of these are a good idea. But ultimately, one of the most important things standing between you and a deadly bout of covid-19 is your immune system. We know that the immune system gets weaker as we age – which is a key reason why those over the age of 70 are most at risk from the disease. But what is becoming clear is that when it comes to immune health, age is just a number. Some people have an immune system that is effectively significantly older or younger than they are. “Some 60-year-olds have the immune system of a 40-year-old, some are more like an 80-year-old,” says Shai Shen-Orr, an immunologist at the Technion-Israel Institute of Technology. The good news is that there are some simple ways to turn back the immunological clock. Because even after the threat of this virus has passed – sooner or later another one is going to come along, and none of us is getting any younger. As anyone who has studied immunology will tell you, the immune system is immensely, mind-bogglingly intricate. “It is the second-most complicated system in your body after your brain,” says Shen-Orr. It consists of hundreds of cell types and signalling molecules controlled by some 8000 genes, interacting in a network of near-infinite complexity. Happily, you don’t need to know all of its intricacies to take advantage of the latest developments in immunology – although a little knowledge can help (see “Immunology at a glance”). If you are younger than 60, in good health and don’t have too many bad habits, then your immune system is probably functioning well enough to keep you safe from almost any infectious disease, including coronavirus. The bad news is that as we age, our immune systems gradually deteriorate too. This “immunosenescence” starts to affect people’s health at about 60, says Janet Lord at the University of Birmingham, UK. The older you get, the weaker your immune system becomes, and the more likely you are to get seriously ill or die because of it.

3-25-20 Here’s where bacteria live on your tongue cells
Mapping how bacteria are grouped together may reveal how they maintain their environment. Myriad microbes dwell on human tongues — and scientists have now gotten a glimpse at the neighborhoods that bacteria build for themselves. Bacteria grow in thick films, with different types of microbes clustered in patches around individual cells on the tongue’s surface, researchers report online March 24 in Cell Reports. This pattern suggests individual bacterial cells first attach to the tongue cell’s surface and then grow in layers as they form larger clusters — creating miniature environments the different species need to thrive. “It’s amazing, the complexity of the community that they build right there on your tongue,” says Jessica Mark Welch, a microbiologist at the Marine Biological Laboratory in Woods Hole, Mass. Methods to identify microbial communities typically hunt for genetic fingerprints from various types of bacteria (SN: 11/05/09). The techniques can reveal what lives on the tongue, but not how the bacterial community is organized in space, Mark Welch says. So she and her colleagues had people scrape the top of their tongues with plastic scrapers. Then the team tagged various types of bacteria in the tongue gunk with differently colored fluorescent markers to see how the microbial community was structured. Bacterial cells, largely grouped by type in a thick, densely packed biofilm, covered each tongue surface cell. While the overall patchwork appearance of the microbial community was consistent among cells from different samples and people, the specific composition of bacteria varied, Mark Welch says. But some bacteria were common across nearly all samples and tended to occupy roughly the same regions around tongue cells. Actinomyces bacteria, for example, were typically at the core of the structure, close to the human cell. Rothia, on the other hand,tended to exist in large patches toward the outside of the biofilm and Streptococcus formed a thin outer layer. Two of these groups — Actinomyces and Rothia — may be important for converting dietary nitrate, a compound abundant in leafy green vegetables, to nitric oxide, which dilates blood vessels and can help regulate blood pressure.

3-25-20 The evolutionary mystery of flying may finally be cracked by genetics
Finding out how flight evolved or animals moved onto land is all about a collision of palaeontology and genetics, argue two new books IN 1871, a now-obscure biologist called St George Jackson Mivart published On the Genesis of Species. As its title suggests, the book was a riposte to Darwin’s theory of natural selection, published in 1859. Mivart had been an avid Darwinian, but the more he thought about it, the stronger his doubts grew. In particular, he couldn’t see how natural selection could account for the appearance of novel structures. This was the start of a debate that has raged ever since: just what caused the major transitions in the history of life? How, for example, did birds evolve flight? Or animals evolve to live on land? The problem is that a small, incremental step towards structures such as wings, feathers or lungs would appear to be of little adaptive value, and so wouldn’t have been selected for by evolution. Ditto the sweeping anatomical and physiological changes required to take to the air or colonise the land. As the late palaeontologist and science writer Stephen Jay Gould put it, what use is 2 per cent of a wing? Pretty much every major transition hits this problem, and creationists exploit it in their attempts to discredit the theory. Neil Shubin at the University of Chicago is well placed to answer the question. As a palaeontologist, he predicted the location of, and then found, the fossilised remains of Tiktaalik roseae, a 375-million-year-old transitional form. Tiktaalik is what we used to call a missing link: it is an intermediate stage between aquatic and terrestrial animals, and one of the best pieces of physical evidence for the theory of evolution. The story of Tiktaalik‘s hard-won discovery in the Canadian Arctic was the centrepiece of Shubin’s excellent previous book, Your Inner Fish. His latest book, Some Assembly Required, plays to his other specialism, molecular biology, where he works to understand how genetics and developmental biology explain such major transitions – for instance, how a class of regulatory genes called Hox orchestrate the development of all body plans.

3-25-20 The number of steps per day, not speed, is linked to mortality rate
An observational study found a benefit as steps added up for women and men. However you can fit some steps in your day, keep it up — and the more, the better. A new study of nearly 5,000 people finds an association between the total number of steps per day and the risk of dying for any reason. Among the 655 participants who took fewer than 4,000 steps per day, the mortality rate was 76.7 per 1,000 people per year. (In distance, 4,000 steps is roughly 3 kilometers.) But among the 1,727 people who managed 4,000–7,999 steps per day, the death rate plummeted to 21.4 per 1,000 people. It got even better for the next group: Among the 1,539 people taking 8,000 to just under 12,000 daily steps, the annual death rate was 6.9 per 1,000 people, researchers report online March 24 in JAMA. Study participants, who were at least 40 years old, wore accelerometers that tracked their steps for up to a week. Researchers collected the data from 2003 to 2006 as part of the National Health and Nutrition Examination Survey, and then followed the participants an average of 10 years, during which time 1,165 of them died. While there was a link between the number of steps per day and the risk of dying, the researchers did not find that the intensity of the steps — the number of steps per minute — was associated with mortality risk in the study.

3-24-20 Higher step count linked to lower yearly risk of death, up to a point
The higher your daily step count, the lower your risk of death per year, according to a new analysis by the US National Cancer Institute – but the link only goes so far. Public health officials have long encouraged walking as a way of improving general health, but many longitudinal studies on its benefits have focused on people in their early 60s and have sometimes ignored minority groups, such as people who aren’t white. The new analysis looked at 4840 people who were representative of the US population over the age of 40. Between 2003 and 2006, Pedro Saint-Maurice at the National Cancer Institute and his colleagues asked the participants to wear an accelerometer for a week. “We know that measuring a person’s activity over seven days is a fairly good gauge of their usual activity,” says Saint-Maurine, because previous studies have used a similar methodology. The team found that the average daily step count of this group was 9124 steps. This figure is higher than many previous studies have found, probably because the study included younger people, those working in less sedentary jobs, and more men, who tend to be more physically active. The researchers used the US National Death Index to determine which participants had died by the end of 2015. The researchers used 4000 steps a day as their baseline, because this is easily achieved by someone who drives to work and sits at their desk for the whole day. By comparison, the team found that taking 8000 steps was associated with a 51 per cent lower risk of dying per year, and taking 12,000 daily steps was associated with a 65 per cent lower risk of dying per year. But taking more than 12,000 steps a day didn’t seem to be associated with a further reduction of risk of yearly mortality. “It just kind of plateaus,” says Saint-Maurice. Up until 12,000 steps, a higher number of steps was associated with a lower risk of dying per year regardless of sex, race, level of education, health condition and whether a person smoked or drank alcohol.

3-24-20 The bacteria in a mother’s gut may protect babies from food allergies
The presence of certain bacteria in a mother’s gut is linked to a decreased risk of their baby developing food allergies in the first year of life. Prevotella copri is a bacterium that ferments fibre from our diet into fatty acids, and it has been linked to reduced allergic reactions in the offspring of mice with a high-fibre diet. Peter Vuillermin at Deakin University in Australia and his colleagues examined whether this association was also found in humans, in whom the fatty acids are thought to help regulate inflammation. The team analysed data from a study of Australian mothers and infants collected between 2010 and 2013. Faecal samples were gathered from women when they were 36 weeks pregnant, and from infants one, six and 12 months after birth. DNA from faecal samples of 58 infants with a diagnosed food allergy were compared with those of 236 infants without allergies. The team found that around 20 per cent of babies without any allergies had P. copri in their faecal samples, compared with 8 per cent of those with allergies to egg, peanut and cow’s milk, among others. The presence and abundance of P. copri in the mother’s stool was also associated with a decreased risk of allergy. In fact, only one mother with an infant who had allergies had more than 0.03 per cent of the bacterium detected in her stool sample. Analysis showed that when a woman had twice as much P. copri as another – as indicated by the expression of a specific P. copri gene in their stool – it was associated with an 8 per cent decrease in the risk of food allergy in her child. P. copri might also be able to protect against non-food allergies such as hay fever, says Vuillermin, especially because childhood food allergies can make subsequent allergies more likely. He adds that large households were a strong forecaster of P. copri being present in the mother’s microbiome, probably because there are more people to share microbiota with, which boosts microbiome diversity.

3-24-20 You could be spreading the coronavirus without realising you’ve got it
With more than 380,000 confirmed cases worldwide, one thing is clear about the new coronavirus: it is very good at infecting people. Now studies are starting to reveal just how infectious it is – and when a person with covid-19 is most likely to spread the virus. While we know some people are more vulnerable to the virus than others, it is capable of putting a healthy adult of any age into a critical condition and in need of intensive care. However, the virus can also be asymptomatic, causing no noticeable illness in some people. Such cases were first recognised in China in January (Science China Life Sciences, doi.org/dqbn), but it wasn’t known how common they were. Research published last week by Jeffrey Shaman of Columbia University in New York and his colleagues analysed the course of the epidemic in 375 Chinese cities between 10 January, when the epidemic took off, and 23 January, when containment measures such as travel restrictions were imposed. The study concluded that 86 per cent of cases were “undocumented” – that is, asymptomatic or had only very mild symptoms (Science, doi.org/ggn6c2). The researchers also analysed case data from foreign nationals who were evacuated from the city of Wuhan, where the first cases were seen, and found a similar proportion of asymptomatic or very mild cases. Such undocumented cases are still contagious and the study found them to be the source of most of the virus’s spread in China before the restrictions came in. Even though these people were only 55 per cent as contagious as people with symptoms, the study found that they were the source of 79 per cent of further infections, due to there being more of them, and the higher likelihood that they were out and about. “If somebody’s experiencing mild symptoms, and I think most of us can relate to this, we’re still going to go about our day,” says Shaman. “These people are the major driver of it and they’re the ones who facilitated the spread.”

3-24-20 We haven’t identified any new drugs for severe covid-19 cases yet
Despite what you may have heard, although several potential drugs for covid-19 are being trialled around the world, few results have been reported yet, and we don’t know if any could help save people who are already seriously ill when diagnosed. Some enthusiastic news stories and claims being spread on social media are based on little more than anecdotal reports. However, the World Health Organization (WHO) is coordinating an international trial of the most promising drugs – and with case numbers soaring, we should find out soon if any of them work. “This trial focuses on the key priority questions for public health. Do any of these drugs reduce the mortality? Do any of these drugs reduce the time the patient is in hospital? And whether or not the patients receiving any of the drugs needed ventilation or an intensive care unit,” said Ana Maria Henao-Restrepo of the WHO at a briefing on 18 March. The WHO trial will include the long-used antimalarial drugs chloroquine and hydroxychloroquine, a new antiviral drug called remdesivir and a combination of two HIV drugs called lopinavir and ritonavir. The HIV drugs will also be tested in combination with an antiviral called interferon beta. On 22 March, several countries in Europe, including the UK, launched a collaborative trial of the same drugs, which will complement the WHO effort. There has been a tremendous buzz about chloroquine after it was highlighted first by entrepreneur Elon Musk and then US president Donald Trump, who wrongly claimed it was already approved in the US for treating covid-19. There is some evidence that chloroquine and the closely related hydroxychloroquine are effective against related viruses such as the one that causes SARS. There have also been reports from China that chloroquine is beneficial when given to people with covid-19 associated pneumonia, but the findings have yet to be published. “It looks promising,” says Robin May at the University of Birmingham, UK.

3-24-20 Mammal study explains 'why females live longer'
A new study that looks at lifespan in wild mammals shows that females live substantially longer than males. The research finds that, on average, females live 18.6% longer than males from the same species. This is much larger than the well-studied difference between men and women, which is around 8%. The scientists say the differences in these other mammals are due to a combination of sex-specific traits and local environmental factors. In every human population, women live longer than men, so much so that nine out of 10 people who live to be 110 years old are female. This pattern, researchers say, has been consistent since the first accurate birth records became available in the 18th Century. While the same assumption has been held about animal species, large-scale data on mammals in the wild has been lacking, Now, an international team of researchers has examined age-specific mortality estimates for a widely diverse group of 101 species. In 60% of the analysed populations, the scientists found that females outlived the males - on average, they had a lifespan that's 18.6% longer than males. "The magnitude of lifespan and ageing across species is probably an interaction between environmental conditions and sex-specific genetic variations," said lead author Dr Jean-Francois Lemaître, from the University of Lyon, France. He gives the example of bighorn sheep for which the researchers had access to good data on different populations. Where natural resources were consistently available there was little difference in lifespan. However, in one location where winters were particularly severe, the males lived much shorter lives. "Male bighorn sheep use lots of resources towards sexual competition, towards the growth of a large body mass, and they might be more sensitive to environmental conditions," said Dr Lemaître. "So clearly the magnitude of the difference in lifespan is due to the interaction of these sex-specific genetics, the fact that males devote more resources towards specific functions compared with females, and to the local environmental conditions." Even if females lived longer than males, the team found that it did not mean that the risks of dying are increasing more in males than females as they get older. The expected male mortality is always higher, but the rate of mortality is about the same in both genders as they age.

3-24-20 Mysterious Iron Age site may have been a retreat for religious hermits
A small, mysterious site in the Czech Republic’s Šumava mountains could have been a nature retreat for religious hermits 2200 years ago. At an elevation of 802 metres, it is the country’s highest site from the late Iron Age, hidden in a forest near a river in Bohemia. Archaeologists found it in 2011 after an uprooted tree exposed pottery fragments from the La Tène culture. But its purpose has baffled researchers. Now, a recent excavation hints at it being a retreat for religious hermits similar to Celtic druids. “It’s the most probable explanation after eliminating all other options,” says Dagmar Dreslerová at the Czech Academy of Sciences in Prague, who led the study. She and her team unearthed around 500 pottery shards which originated from over 100 ceramic containers dating from 190 to 50 BC. Of the fragments, 24 were tested for fatty substances called lipids, which revealed traces of cow fat and olive or hazelnut oil. What is more, a chemical was present that forms only when fat is heated above 300°C. This suggests some pots were used for cooking beef or for making tallow to preserve meat or produce candles. No signs of farming, animal slaughter or tools were found at the site, indicating the beef was cooked and potted elsewhere. Seasonal fishing, hunting or mining might explain why food was brought in, but there was no evidence of such activities. A long-distance trade route is thought to have passed nearby, offering the possibility that path maintenance workers, guides or guards used the site. However, the olive or hazelnut oil suggests something else. “It’s unlikely these people would have such a luxurious item,” says Dreslerová. But people of high social standing such as druids could have. Druids are confined to Celtic culture, but religious specialists are known to have existed in Iron Age Bohemia. So it is plausible they retreated to secluded areas such as caves or forests to spend time as hermits or to teach.

3-24-20 Fossil worm shows us our evolutionary beginnings
A worm-like creature that burrowed on the seafloor more than 500 million years ago may be key to the evolution of much of the animal kingdom. The organism, about the size of a grain of rice, is described as the earliest example yet found in the fossil record of a bilaterian. These are animals that have a front and back, two symmetrical sides, and openings at either end joined by a gut. The discovery is described in the journal PNAS. The scientists behind it say the development of bilateral symmetry was a critical step in the evolution of animal life. It gave organisms the ability to move purposefully and a common, yet successful way to organise their bodies. A multitude of animals, from worms to insects to dinosaurs to humans, are organised around this same basic bilaterian body plan. Scott Evans, of the University of California at Riverside, and colleagues have called the organism Ikaria wariootia. It lived 555 million years ago during what geologists term as the Ediacaran Period - the time in Earth history when life started to become multi-celled and much more complex. The discovery started with tiny burrows being identified in rocks in Nilpena, South Australia, some 15 years ago. Many who looked at these traces recognised they were likely made by bilaterians, but creatures' presence in the ancient deposits was not obvious. It was only recently that Scott Evans and Mary Droser, a professor of geology at UC Riverside, noticed minuscule, oval impressions near some of the burrows. Three-dimensional laser scanning revealed the regular, consistent shape of a cylindrical body with a distinct head and tail and faintly grooved musculature. Ikaria wariootia ranged in size between 2mm and 7mm long, and about 1-2.5mm wide. The largest of the ovals was just the right size and shape to have made the long-recognised burrows. "We thought these animals should have existed during this interval, but always understood they would be difficult to recognise," Scott Evans said. "Once we had the 3D scans, we knew that we had made an important discovery." Ikaria wariootia probably spent its life burrowing through layers of sand on the ocean floor, looking for any organic matter on which it could feed.

3-23-20 Machine 'could quadruple' heart and lung transplants
The number of heart and lung transplants could quadruple thanks to a "reanimation" machine used in a pioneering operation, a hospital says The device, developed at Royal Papworth Hospital in Cambridge, managed to pump oxygenated blood into both organs in a world-first procedure. The machine can revitalise deteriorating organs allowing "donation after circulatory death" (DCD). Hospital surgeon Pedro Catarino said it was like "recharging the batteries". "It is reanimation and then it replenishes the energy stores of the heart, what we call reconditioning, which allows it be transplanted," he said. "We think it could at least double and perhaps quadruple the number of [heart and lungs] available for transplant." He said it was desperately needed, adding: "Patients die on the waiting list every day." Most organs come from people who are brain dead. Crucially, doctors are able to keep their hearts beating and healthy until they are removed. Unusually, Aaron Green's came from a donor who was circulatory dead - in other words, their heart had stopped beating and their organs had begun to decay. "With brain death we've got four hours to get the organ from the donor into the recipient. With this circulatory death we have no more than 30 minutes to get the organ on to the machine," said Dr Catarino. Royal Papworth Hospital has been doing DCD heart transplants for five years, but last summer it performed a heart and lung transplant using the new machine. Mr Green, 25, is still currently the only person in the world to have a heart and lungs from a donor whose heart had stopped. He said: "The first thing I remember was I woke up, looked at my hand and went, 'Oh, it's not blue'. "I couldn't believe how quickly the heart and lungs kicked in - it was straight away." Mr Green left hospital two months after the operation and was back playing cricket and riding his bike.

3-23-20 A tooth-enamel protein is found in eyes with a common form of macular degeneration
The finding could point to a new target in treating the ‘dry’ form of the disorder. Deposits of a mineral found in tooth enamel at the back of the eye could be hastening the progression of age-related macular degeneration, the leading cause of deteriorating eyesight in people over 50. Now researchers have identified a protein called amelotin that experiments suggest is involved in producing the mineral deposits that are the hallmark of “dry” age-related macular degeneration, the most common of the two forms of the disease. Age-related macular degeneration, or AMD, affects about 3 million people in the United States. But the new finding, if confirmed, could change that. While the “wet” form of AMD, which comprises up to 30 percent of AMD cases, can be treated with injections, there are currently no treatments for dry AMD. “Finding amelotin in these deposits makes it a target to try to slow the progression of mineralization, which, if it’s borne out, could result in new therapies,” says Imre Lengyel, an ophthalmologist at Queen’s University Belfast in Scotland who was not involved in the research. These deposits, first documented in 2015, are made of a type of mineralized calcium called hydroxyapatite and appear beneath the retinal pigment epithelium — a layer of cells just outside the retina that keeps its light-sensing rods and cones happy and healthy. The deposits may worsen vision by blocking the flow of oxygen and nutrients needed to nourish those light-sensitive cells of the retina. By contrast, in wet AMD abnormal blood vessels intrude into the retina and often leak. Both types of AMD distort a person’s central vision — the focused, detailed sight needed for reading and recognizing faces — which can make independent living difficult. For the new study, published online February 26 in Translational Research, researchers grew retinal pigment epithelial cells in the lab, and then subjected them to a form of stress that may be common in aging eyes: a loss of nutrients.

3-21-20 Diamond samples in Canada reveal size of lost continent
Canadian scientists have discovered a fragment of an ancient continent, suggesting that it was 10% larger than previously thought. They were studying diamond samples from Baffin Island, a glacier-covered land mass near Greenland, when they noticed a remnant of North Atlantic Craton. Cratons are ancient, stable parts of the Earth's continental crust. The North American Craton stretched from present-day Scotland to North America and broke apart 150m years ago. Scientists chanced on the latest evidence as they examined exploration samples of kimberlite, a rock that often contains diamonds, from Baffin Island. "For researchers, kimberlites are subterranean rockets that pick up passengers on their way to the surface," University of British Columbia geologist Maya Kopylova said. "The passengers are solid chunks of wall rocks that carry a wealth of details on conditions far beneath the surface of our planet over time." Ms Kopylova and her colleagues says the sample bore a mineral signature that matched other portions of the North Atlantic Craton. "Finding these 'lost' pieces is like finding a missing piece of a puzzle," Ms Kopylova is quoted as saying in an article published by the University of British Columbia's website. The samples were taken from deep below the Chidliak Kimberlite Province in southern Baffin Island. Previous reconstructions of the Earth's plates had been based on shallow rock samples formed at depths of one to 10km (six miles). Ms Kopylova said the discovery adds about 10% to the known size of the craton. "Our knowledge is literally and symbolically deeper," she said.

3-21-20 Why some heart patients may be especially vulnerable to COVID-19
People with hypertension and cardiovascular disease risk severe bouts of the disease. As researchers examine deaths from COVID-19, heart patients appear especially vulnerable. In Italy, where the number of deaths has now surpassed those in China, public health officials reported on March 17 that among 355 people who died, a whopping 76 percent had hypertension and 33 percent had heart disease. And among more than 44,000 confirmed cases of COVID-19 in China (SN: 2/25/20), the case fatality rate for people with underlying conditions was highest for those with cardiovascular disease, at 10.5 percent compared with the overall fatality rate of 2.3 percent. Researchers know generally that infections can take a toll on people who have other health problems. But SARS-CoV-19, the virus that causes COVID-19, may pose particular danger to the heart because of how the virus gets into cells, researchers speculate. To invade a cell, SARS-CoV-2 latches onto a protein called angiotensin-converting enzyme 2, or ACE2 (SN: 3/3/20). This protein is found on cells in the lungs, allowing the virus to invade these cells and cause respiratory symptoms. But ACE2 also is on heart muscle cells and cells that line the blood vessels. Considering the involvement of ACE2, COVID-19 may damage the heart directly, researchers write in a commentary in Nature Reviews Cardiology March 5. According to studies out of Wuhan, China, where the outbreak started, some people with COVID-19 have developed myocardial injury, the death of heart cells for reasons other than a heart attack. But ACE2 does more than offer an entry point for SARS-CoV-2. The protein is also part of a wide-ranging system of hormones, called the renin angiotensin aldosterone system, that regulates blood pressure and cardiovascular and kidney function. Drugs that target other parts of this system are widely prescribed to lower blood pressure in people with hypertension and cardiovascular disease.

3-21-20 How the body builds its tubes and branches
At first glance, our bodies seem impossibly complex, with dozens of organs built to precise specifications in exactly the right places. It seems almost miraculous that all this could develop automatically from a single fertilized egg. But look a little closer and you'll see that evolution, the master architect, has been economical with that complexity, relying on the same components again and again in different contexts. Take tubes, for example. "We're basically a bag of tubes," says Celeste Nelson, a developmental bioengineer at Princeton University. "We have a tube that goes from our mouth to our rear end. Our heart is a tube. Our kidneys are tubes." So, too, are lungs, pancreas, blood vessels, and more — most of them intricate systems of tubes with many branches. Branching tubes appear so often because they are the best solution to a key problem that organisms face as they get bigger: As an animal grows, its volume goes up faster than its surface area. That simple physical relationship means that the logistical challenges of supplying oxygen and nutrients, and removing waste products — all of which ultimately depend on diffusion through the surfaces of cells — get more daunting with size. But a dense forest of branching tubes increases the available surface area enormously. "They allow us to be big," says Jamie Davies, a developmental biologist at the University of Edinburgh. In recent years, Davies, Nelson, and a few other developmental biologists have made great progress in understanding how the body makes tubes and branches in a variety of organs. Though the details usually vary from one organ to the next, some basic principles are beginning to emerge, as outlined in an article coauthored by Nelson in the Annual Review of Biomedical Engineering. So far, it looks like there are only a few ways to make a tube, only a few ways to control how it branches, and only a few ways to regulate when branching should stop.

3-20-20 Coronavirus basics: What to do if you think you’re infected
Know the symptoms The most common symptoms of Covid-19 are a fever, a dry cough, and difficulty breathing, though some patients also experience diarrhea, nausea, and vomiting. Do not assume you are virus-free and noncontagious if you haven’t yet shown symptoms, but for now, seek testing only if you are symptomatic or have been in contact with someone who has tested positive. Seek medical attention immediately if your symptoms include persistent chest pain, confusion, or a bluish face or lips. Call your doctor If you have a fever, dry cough, or other worrisome symptoms, your doctor can determine whether you should be tested. Test kits are currently hard to come by in many areas, but you can expect a test in which a swab is inserted in one nostril, with results after a wait of a few days. If you are told to visit a doctor’s office or ER, call ahead so that staff can take precautions, and wear a kerchief or respiratory mask to contain your cough. Don’t bother with masks if you’re not sick, because there’s a nationwide shortage and health-care workers need them. Self-quarantine Most people who contract the virus will recover without intervention, so if you’re not considered high-risk and don’t require urgent medical attention, stay home and self-isolate for at least two weeks, avoiding even the people you live with. Stay in your own bedroom, and ideally, use your own bathroom. Wash your hands often, only grab food when no one else is in the kitchen, and disinfect any surfaces you touch. Drink lots of water, sleep as much as possible, run a humidifier, and manage symptoms with over-the-counter cough suppressants and fever reducers such as Tylenol. Your doctor can tell you when you’re no longer contagious. Sources: CDC.gov and Vox.com

3-20-20 Are there multiple strains of Covid-19?
Scientists in China believe they have identified two unique strains of the new coronavirus—a discovery that, if confirmed, could mean new variants will crop up year after year in the same way as seasonal flu. Researchers from Peking University examined the genetic sequences of viral samples from 103 Chinese Covid-19 patients. They say they found two forms of the virus: “L-type” and “S-type.” The L-type was more prevalent among those who had the disease early in the outbreak; the S-type was more common in later samples. Counterintuitively, it appeared that the former was derived from the latter. Researchers think the S-type didn’t make as big an impact initially because it isn’t as virulent. The differences between the two are tiny; they both carry the same symptoms and are equally deadly. But if there are indeed two strains, it’s safe to assume that more will emerge in the months and years ahead. That’s how seasonal flu works: New variants crop up as viruses mutate to overcome people’s immune systems. Some scientists have questioned the finding, noting that the study is based on a small sample and that such mutations don’t make the virus behave differently. But others say the research shows that the coronavirus will be with us for years to come. Ian Jones, from Reading University in the U.K., tells New Scientist: “I don’t see it going away any time soon.”

3-20-20 Convalescent serum
Researchers at Johns Hopkins University are hoping to use the blood of patients who’ve recovered from the coronavirus to treat severe infections. They hope “convalescent serum” containing antibodies harvested from the recovered patients’ blood might be used to slow or treat the disease. Doctors using similar transfusions during the Spanish flu epidemic of 1918 reported a 50 percent drop in deaths.

3-20-20 Anxiety and bad-sleeping babies
Babies who are poor sleepers may be at greater risk of developing anxiety and emotional issues later in childhood. In a decade-long study, Australian researchers tracked 1,507 first-time mothers and their children, reports CNN.com. Each mother recorded her baby’s sleeping pattern every three months for the first year after birth, and then answered questions about the child’s mental health at 4 and 10 years of age. During their first year, 20 percent of the children had “persistent severe sleep problems”—waking up multiple times during the night and struggling to settle back down. Compared with the children who slept well as infants, these poor sleepers were almost three times more likely to show signs of emotional difficulties at age 4, and twice as likely by age 10. The emotional issues included separation anxiety, fear of physical injury, and elevated anxiety. “These results may mean that sleep issues result in later problems,” says Jodi Mindell from the Children’s Hospital of Philadelphia, who wasn’t involved in the study. “But it is just as likely that sleep problems are an early indicator.”

3-20-20 Low-carb diet good for brain
Eating fewer carbohydrates might prevent and could even reverse age-related damage to the brain, reports The Guardian (U.K.). Researchers examined brain scans of nearly 1,000 people, ages 18 to 88, and found that the rate of damage to neural pathways varied depending on the brain’s main source of energy. Glucose, the sugar broken down from carbohydrates, accelerated the damage; ketones, produced by the liver during low-carb diets, slowed it down. The researchers also found that people can start experiencing damage in their neural pathways as early as their late 40s. “The bad news is that we see the first signs of brain aging much earlier than was previously thought,” says lead author Lilianne Mujica-Parodi, from Stony Brook University in New York. “The good news is that we may be able to prevent or reverse these effects with diet.” A high-ketone diet is low in carbohydrates and high in fats and proteins; further research is needed to determine whether the possible neurological benefits of such a diet outweigh its impact on heart health.

3-20-20 Dinosaur days were shorter
When dinosaurs walked the earth, days were about half an hour shorter than they are now, reports USA Today. That’s the conclusion of a new study into a 70 million–year-old fossil of a mollusk shell, below. The mollusk, which lived for about nine years on a shallow seabed in what is now Oman, grew fast and is thought to have produced daily growth rings. Using lasers to sample tiny slivers of its shell, scientists were able to count these growth rings. “We have about four to five data points per day, and this is something that you almost never get in geological history,” says lead author Niels de Winter, from Vrije Universiteit in Brussels. “We can basically look at a day 70 million years ago. It’s pretty amazing.” From their analysis, de Winter and his team concluded that days lasted about 23 hours and 30 minutes in the Cretaceous period. Earth turned faster then than it does today, clocking up to 372 rotations a year rather than 365; over time, friction from ocean tides—which are driven by the gravity of the moon—has steadily slowed the planet’s rotation.

3-20-20 HIV drugs didn’t work as a coronavirus treatment in a clinical trial
Antivirals called lopinavir and ritonavir ‘showed no benefit’ when given to severely ill people. Doctors, researchers and health officials scrambling to find treatments for coronavirus-infected patients may have had one hope dashed. Researchers had hoped that antiviral drugs used to treat HIV might also work against the coronavirus, known as SARS-CoV-2 (SN: 3/10/20). Both HIV and the coronavirus need an enzyme called a protease to make infectious virus. The drugs inhibit the action of the protease. A trial of 199 people randomly assigned to get the drugs plus standard care — including supplemental oxygen, antibiotics for follow-on bacterial infections and other measures as needed — or standard care alone has deflated those hopes. The trial in Beijing tested the HIV drugs, called lopinavir and ritonavir, on people who were severely ill with pneumonia caused by COVID-19. Comparing outcomes from 94 people who got the drugs with results from 100 patients who received standard care showed no benefit to the drugs, researchers report March 18 in the New England Journal of Medicine. The drugs shortened the time it took to see clinical improvement from 16 days in the standard care group to 15 days in the treatment group. But that slightly shorter improvement time happened only for people who got the drugs within 12 days of symptoms appearing. That finding may suggest that the people in the trial were too ill already to benefit from the drugs, and treatment earlier in the infection may work better, the researchers suggest. That possibility has not yet been tested. The HIV drugs didn’t stop viral replication as measured by testing for RNA, the virus’s genetic material. Researchers don’t know whether people who got the drugs produced fewer infectious viruses.

3-20-20 A new book captures how genetics fills in the story of life’s evolution
‘Some Assembly Required’ explores how genetic analyses complement paleontological research. When descendants of ancient fish first hauled themselves onto dry land, they didn’t do so with lungs evolved specifically for that reason. The need to breathe air ultimately led to a change in the function of an organ the fish already had. Likewise, when birds took to the air millions of years later, they did so using feathers that may have originally evolved as insulation or as a way to attract mates. In Some Assembly Required, Neil Shubin, a paleontologist, explores these and other great evolutionary innovations, as well as the invisible genetic changes that made them possible. The book is an impressive chronicle of what genetic research over the last few decades has done to complement the story of evolution, a tale once told through fossils, anatomy and physiology alone. For instance, studies show that the genes fish need to build swim bladders — the organ that helps control buoyancy — are the same ones lungfish and humans use to build lungs. Such repurposing, of both genes and anatomical features, is a recurrent theme in the tree of life, Shubin notes. In some cases, genetic mutations trigger the production of new proteins, which can either serve new functions or perform old tasks more efficiently and, in turn, enhance the survival of the organism. In other cases, mutations cause genes to be switched on or off earlier or later in development and at different places in an embryo. These changes can alter the development of skulls, fins, limbs and other anatomical features, and sometimes result in totally new features. Many of these tweaks may arise when genes duplicate themselves, a process that allows one copy of a gene to retain its original function but frees up the additional copy to change and gain a new purpose. For instance, research suggests that the gene NOTCH2NL, which originated via duplication of a more primitive gene and is found in humans but not monkeys, triggers the growth of brain cells when inserted into the DNA of lab mice. The gene probably contributes to humans’ big brain, scientists have proposed.

3-19-20 Genetically modified neurons could help us connect to implants
Here come the cyborgs. The electrical properties of specific types of nerve cell in living animals have been changed by genetically modifying them to produce conducting polymers on their surfaces. The work, which promises to allow electrical control of specific groups of cells, could lead to everything from new treatments for conditions such as epilepsy to better ways of connecting prosthetic limbs to nerves, says Zhenan Bao of Stanford University in California. “Those are definitely possibilities,” she says. At present, electrical implants such as those used for treating Parkinson’s disease often consist of metal electrodes pushed into the brain. One of the disadvantages is that there is no way to control the activity of specific types of neuron. Bao and her colleagues genetically modified specific cell types to produce an enzyme on their surface that joins small molecules – monomers – together to make a chain, or polymer. The polymer can be either an electrical conductor or insulator depending on the monomer. The team did this first with animal and human cells in a dish, then with miniature human brain-like structures in the lab and finally in living nematode worms. The worms were first soaked in the monomers that the enzymes join to make the polymers. In larger animals, the monomers would need to be injected. The researchers showed that this approach resulted in the targeted nerve cells becoming coated in the polymer, and that this altered the behaviour of the cells as they had expected it would. For instance, targeting the neurons that control movement made the worms less likely to move forward, or more likely to make sharp turns, depending on the type of polymer. The researchers don’t yet understand why the modifications have these effects, says Bao. Nor have they yet attempted to connect to or interact with the modified neurons. But the results are proof of principle, she says. “It took many years.”

3-19-20 Is your salad going to kill you?
#Facts matter | Plants need nitrates for good growth, but they can also accumulate in leaves of crops like rocket. So are foods like this safe to eat, wonders James Wong. EATING healthily can be tricky, especially for avid followers of the latest food- related headlines. Even fare touted as a superfood one day can be vilified as a cancer risk the next. Perhaps nowhere is this more the case than in recent claims about rocket, a salad leaf. It is “at the centre of cancer concerns”, said one story, a strong accusation to level at a humble leaf. The claim hinges on high levels of nitrates that rocket contains. Is there any clear evidence to back it up? No, not when you dig a bit deeper into the complex findings around this. Nitrates are naturally occurring mineral compounds that plants need for healthy growth. These are drawn up from the soil and become concentrated in the leaves in some species. It has long been known that rocket is a particularly potent accumulator of these substances. So what is the issue? Well, from the late 20th century, we started becoming concerned that nitrates might pose a health hazard. This was largely about their presence in drinking water as a consequence of fertiliser that washes off farmland and their use as food additives, for example to preserve processed meats. Those worries were sparked by experiments that involved feeding large quantities of nitrates to rats, which suggested a raised risk of conditions such as stomach cancer. Based on these findings, legislation was brought in decades ago by the likes of the World Health Organization and the European Union to limit nitrates in food to what were considered safe levels. Given nitrates are in rocket, the rules applied to it too. How strong was the evidence on nitrates though? It is important to remember that, in science, not all evidence is created equal. The results of animal studies are often a poor guide to what will happen in people. Furthermore, feeding lab rats heavily nitrate-laced water isn’t exactly a great proxy for our salad consumption. Studies that look for a relationship between real-world behaviours in people (such as tracking actual nitrate consumption) and health are generally considered far better evidence. So what do these show?

3-19-20 DNA analysis reveals just how intertwined ancient human lineages are
Ancient human populations in Africa probably mixed far more than we previously thought. That is just one of the revelations about our genetic history that has been uncovered by sequencing the genomes of people from populations previously underrepresented in human genetic studies. “We identified a lot of genetic variation that had not been found before,” says Anders Bergstrom at the Wellcome Sanger Institute in Cambridge, UK. Bergstrom and his colleagues sequenced the genomes of 929 people from 54 different populations across the globe, including in Europe, the Middle East, Africa, America, Central and South Asia, East Asia and Oceania. They discovered hundreds of thousands of new gene variants that were common in many of the populations they studied but that had previously been missed, due to a lack of DNA sequences from people of non-European descent in existing data sets. Among the new discoveries that Bergstrom and his colleagues made was the finding that there was probably much more mixture between different ancient human populations in Africa than suggested by previous studies. Rather than a diverging family tree, they found evidence for much more gene flow between different populations. “It’s more like a kind of intertangled mesh of branches,” says Bergstrom. This hints at how ancient humans migrated out of Africa. Rather than a population separating into two and never seeing each other again, people probably continued to move between groups in a much more complex way, he says. The team also found more detailed evidence of our ancient human ancestors mating with other hominids. We already knew that our ancestors mated with archaic human groups, including Neanderthals and Denisovans, but until now it wasn’t clear how frequently this occurred and whether they mated with some groups more than others.

3-19-20 We're beginning to understand the biology of the covid-19 virus
Scientists are working around the clock to understand the biology of the covid-19 virus and how it infects human cells, which will help us design treatments to stop it. THE covid-19 virus is humanity’s newest foe, with the potential to prematurely end millions of lives. To control this new coronavirus, we need to understand it. Labs around the world are now working around the clock in a bid to know their enemy. Three crucial questions are occupying virologists. What makes the new virus so good at infecting people? How does it reproduce so quickly once it is inside us? And why doesn’t the virus cause symptoms straight away, allowing it to spread undetected? The answers will suggest ways to treat the disease and develop vaccines (see “How soon will we have a vaccine?“). Clues can be found in the virus’s biology. Like all viruses, the covid-19 virus must infect living cells in order to reproduce. Each virus strives to burrow into a cell and take over its internal machinery, repurposing it to build the components of new viruses. These new viruses are then ejected from the cell, where they can infect more cells – either in the same body, or in a new host. The covid-19 virus belongs to a family of coronaviruses, which are fairly intricate as viruses go. Each coronavirus has at its core a strand of RNA, a molecule similar to DNA that carries the virus’s genes. Around this is a protein shell, which is surrounded by two layers of molecules called lipids. This outer membrane is dotted with proteins, some of which stick out like the spikes on a sea urchin. The spike proteins are critical, says Michael Letko at the National Institute of Allergy and Infectious Diseases in Montana. They act as an anchor for the virus, attaching to a protein on the outside of a cell.

3-19-20 Fish used for sushi now carry 283 times more parasites than in 1980s
Fish are infected with 283 times more parasitic worms than they were 40 years ago. Anisakis worms can infect a variety of marine fish and squid, as well as marine mammals such as whales and dolphins – and can be present in fish used raw for sushi. Chelsea Wood at the University of Washington in Seattle and her colleagues analysed the abundance of Anisakis, or herring worm, between 1978 and 2015. The team gathered data on the average number of parasites per fish from 123 studies – which included 56,778 fish across 215 species – and found a 283-fold increase over nearly 40 years. Anasakis starts its life cycle in the intestines of marine mammals, is excreted into their faeces and then infects fish, small crustaceans or krill in the larval stage. “If eaten by fish they go on to form a cyst in the muscle tissue of that fish,” says Wood. When the fish gets eaten by the marine mammal, the life cycle recommences. Humans can also contract these parasitic worms by consuming infected fish that is raw, smoked or improperly frozen. However, the worm can’t survive in us. “When they enter the intestine of a human, it’s a great disappointment to the worm. They’re not going to be able to complete their life cycle there,” says Wood. But the presence of this parasite can still initiate an immune response in people that can cause nausea, vomiting and diarrhoea. Wood says fish consumers needn’t be overly worried. The seafood processing industry and sushi chefs are skilled at spotting and removing these worms, she says. “I still eat sushi all the time.” The reason for the increased abundance of the parasites is unclear, but Wood says that it may be linked to the rise in marine mammal numbers from the 1970s onwards after the introduction of protections against hunting. Warming seas could also increase the rate of Anasakis reproduction, she says.

3-19-20 Our guts may sense sugar and low-calorie sweeteners differently
Can you taste the difference between a calorie-laden sugar and a zero-calorie sweetener? Specialised cells in your gut can, according to experiments in mice. These cells tell the brain whether a sugar or sweetener has been ingested within milliseconds. Research in the 1950s revealed that food doesn’t need to pass through the mouth to stimulate a response from the brain. Mice respond to food rewards when they are put directly into their stomachs, too. More recent studies have found that mice favour sweet foods even when their taste receptors don’t work. A couple of years ago, Diego Bohorquez at Duke University in North Carolina and his colleagues identified a new type of cell that gives the gut its own ability to sense different nutrients. These cells, called neuropod cells, were spotted in the intestines of mice, and rapidly communicate with the brain via the vagus nerve, informing the brain of the presence of sweets. To find out whether these cells can tell the difference between calorific sugar and zero-calorie sweeteners, the researchers infused nine sugars or sweeteners into the guts of mice. At the same time, the team used a device to measure the activity of the vagus nerve, which connects the gut directly to the brain. All of the sugars triggered the neuropod cells to send a signal to the vagus nerve – except for fructose. The fact that fructose – a natural sugar found in fruit – doesn’t seem to trigger a rapid signal to the brain may explain why fruit doesn’t give our brains the same reward as chocolate, says Elisa Hill at RMIT University in Australia, who wasn’t involved in the work. “It would be great to know if these systems can be trained to favour fruit over chocolate,” she says. In other experiments, Bohorquez and his colleagues studied organoids – lumps of living tissue grown from cells taken from the intestines of mice or humans. The team found that only sugars with calories triggered the release of a compound called glutamate as a signal to the vagus nerve. Zero-calorie sugars had a different effect – they delivered an entirely separate signal to the vagus nerve, via a compound called ATP.

3-19-20 50 years ago, scientists were trying to get a grip on Lassa fever
In January 1969 an unknown virus was isolated for the first time from the sera of two nurses, who died.… The infection, being called Lassa fever, involved almost all the body’s organs.… Doctors so far suspect that the disease was transmitted by an animal, but what animal is not known. It is also believed that the patients can acquire the infection from one another, but only through more than casual contact. Named for the Nigerian village where cases first appeared, the Lassa virus causes hemorrhagic fever and kills about 5,000 of the hundreds of thousands of people infected each year in West Africa. The virus, spread by the Natal multimammate rat (Mastomys natalensis), can be transmitted through human body fluids. The World Health Organization considers the creation of a vaccine a high priority. Of nearly 30 vaccines in development, only one has been tested in people. One clinical trial of that vaccine’s safety and efficacy began in the United States in May 2019, and another trial is set for Liberia, Nigeria and Ghana this month.

3-19-20 We may have started keeping lapdogs as pets 2000 years ago
An archaeological excavation in southern Spain has uncovered the 2000-year-old remains of a lapdog that may have been born thousands of kilometres to the east, a discovery that hints at a long-distance trade in lapdogs across the Roman world. The first domestic dogs resembled wolves and may have been used for hunting. But by the time the Roman Empire emerged, selective breeding in Europe and Asia had begun to produce dogs in all manner of shapes and sizes – including tiny dogs that may have been similar in appearance to modern Pomeranians. “[Roman naturalist] Pliny the Elder says that these small dogs had medicinal uses, to relieve menstrual pain in women, for example,” says Rafael Martinez Sánchez at the University of Granada, Spain. Perhaps Pliny meant that holding a warm lapdog against the belly was soothing, he adds. Martinez Sánchez and his colleagues found a lapdog skeleton buried in a Roman cemetery in southern Spain. It stood about 22.5 centimetres tall at the shoulders, and it had a small skull with large eyes, rather like a modern Pekinese. Wear on the dog’s teeth show it was an adult that was probably between 2 and 4 years old when it died. Even tinier fetal bones found inside the small skeleton suggest that the lapdog was a female and that she was pregnant when she died. When Martinez Sánchez and his colleagues analysed the lapdog’s bones and teeth they made a surprising discovery: she may not have been local. Carbon and oxygen isotopes locked away in her bones provide information on the environment an animal’s food and water came from, and they suggest the lapdog grew up drinking water far away from the Atlantic. This means she was probably not born in southern Spain but somewhere to the east, says Martinez Sánchez: perhaps Italy or even somewhere in the eastern Mediterranean. Two other larger dogs buried in the same cemetery lacked this chemical signal, and appear to have been born and raised locally.

3-19-20 ‘Wonderchicken’ is the earliest known modern bird at nearly 67 million years old
The animal is a common ancestor of today’s ducks and chickens. Behold the Wonderchicken, the earliest modern bird ever found. Asteriornis maastrichtensis lived 66.7 million years ago, less than a million years before the asteroid impact that doomed all nonavian dinosaurs. The winged and beaked descendants of this quail-sized bird, however, survived that mass extinction event, forming a long lineage that includes modern chickens and ducks. Based on analyses of fossil remains, which consist of a nearly complete skull and a few limb bones, the bird is closely related to the most recent common ancestor of land fowl and waterfowl, researchers report March 18 in Nature. A. maastrichtensis’ skull is “a never previously seen mashup of ducklike and chickenlike features,” says Daniel Field, a vertebrate paleontologist at the University of Cambridge. “It’s like a turducken.” Previous estimates, based on molecular analyses of living bird groups, suggest that modern birds evolved before the mass extinction event roughly 66 million years ago. But this is the first fossil to definitively place a modern ancestor on the scene. The age of the fossil, in fact, suggests that those previous estimates, ranging from 139 million to 89 million years ago, might have overestimated how early these birds arose, Kevin Padian, a vertebrate paleontologist at the University of California, Berkeley, writes in a commentary in the same issue of Nature. Modern-type birds share several key traits, such as toothless beaks and fused foot bones. The almost 11,000 living bird species — the paleognaths (flightless birds such as ostriches), anseriformes (waterfowl), galliformes (land fowl) and neoaves (the remaining 95 percent of living bird species) — all share a common ancestor, Field says. “We think that ancestor lived at some time before the end of the Age of Dinosaurs,” he says. But there are very few bird fossils surviving from before the asteroid impact.

3-18-20 How soon will we have a coronavirus vaccine? The race against covid-19
The hope is that we will have a coronavirus vaccine in 12-18 months, but for that to happen we may have to rely on untested techniques - and that comes with its own risks. POTTERING around her kitchen on the morning of 31 December, Kate Broderick scrolled through the headlines while she waited for her tea to brew. One story caught her eye: a mysterious outbreak of severe pneumonia in Wuhan, China. Nearly overnight, the number of cases seemed to explode. “I knew we didn’t have time to wait,” she says. A molecular geneticist at Inovio Pharmaceuticals in California, Broderick was poised for what came next. When Chinese officials published the genetic sequence of the new SARS-CoV-2 coronavirus causing the illness just two weeks after the first cases were reported to the World Health Organization, Broderick got to work. Within 3 hours, her team had a prototype vaccine ready for initial testing. It was an unprecedented turnaround, but a moment Broderick and many others had long seen coming. Making vaccines usually takes a decade or more between development, safety testing and manufacturing, says Seth Berkley, head of Gavi, an international group that promotes vaccine use around the world. With global confirmed cases of the new disease, covid-19, surging past 180,000 at the time of writing, time is of the essence. To speed things up, scientists are turning to untested classes of vaccines, and rethinking every part of how they are designed, evaluated and manufactured. If the approach works, we will, for the first time, have identified a new disease and developed a vaccine against it while the initial outbreak is still ongoing. But speed can come with downsides. “We could have a vaccine in three weeks, but we can’t guarantee its safety or efficacy,” says Gary Kobinger, a virologist at Laval University in Canada.

3-18-20 To fight the coronavirus pandemic effectively we need lots more data
Evidence from China suggests the way to get on top of the covid-19 outbreak is through rapid testing, isolation and quarantine rather than lockdowns and big travel restrictions. ABRUPTLY, the world is in lockdown. Many of the countries that aren’t there yet will be there shortly. In the UK, advice to stay at home and government restrictions have arrived more slowly than in neighbouring nations. That has sparked criticism from a number of scientists outside the government science advisory team. Such disagreement has been confusing for a public so often encouraged to trust the experts, especially in the middle of this pandemic. Who do they trust when the experts disagree? The fact is: no one knows what the correct course of action is. Epidemiologists have a saying: “If you’ve seen one pandemic, you’ve seen one pandemic.” We are in an entirely novel situation, not least because coronavirus is so notably different from flu. We will understand this pandemic only when we have more data. That is why, as countries scramble to boost their intensive care capacity, they should also listen to the advice coming from the World Health Organization to “test, test, test”. As WHO assistant director general Bruce Aylward tells us in this issue: “To actually stop the virus, [China] had to do rapid testing of any suspect case, immediate isolation of anyone who was a confirmed or suspected case, and then quarantine the close contacts for 14 days so that they could figure out if any were infected. Those were the measures that stopped transmission in China, not the big travel restrictions and lockdowns.” There are hard days ahead. Aylward explains that lockdown is the hard part, and effectively isolating all covid-19 cases is the really hard part. Our feature on the race for a vaccine (see “How soon will we have a coronavirus vaccine? The race against covid-19“) reinforces the fact that there will be no quick or neat solutions to this crisis.

3-18-20 The stunning east Asian city that dates to the dawn of civilisation
The mysterious Liangzhu civilisation was a neolithic "Venice of the East", rivalling ancient Egypt and Mesopotamia with its engineering marvels. NEARLY five-and-a-half millennia ago, a bustling metropolis lay in the delta of the lower Yangtze, in what is now China. You could enter on foot – there was a single road through the towering city walls – but most people travelled by boat via an intricate network of canals. At its heart, was a massive palatial complex built on a platform of earth. There were huge granaries and cemeteries filled with elaborately decorated tombs, while the water system was controlled by an impressive series of dams and reservoirs. The inhabitants of this city, known today as Liangzhu, ruled the surrounding floodplains for nearly 1000 years, their culture extending into the countryside for hundreds of kilometres. Then, around 4300 years ago, the society quickly declined, and its achievements were largely forgotten. It is only within the past decade that archaeologists have begun to reveal its true importance in world history. Their startling discoveries suggest that Liangzhu was eastern Asia’s oldest state-based society, and its infrastructure may even have surpassed the achievements of Egypt and Mesopotamia, thousands of miles to the west. “There’s nothing in the world, from my vantage point, that is as monumental in terms of water management – or for that matter, any kind of management – that occurs so early in history,” says Vernon Scarborough at the University of Cincinnati in Ohio. One of the biggest chapters in humanity’s story, the birth of civilisation, may need to be rewritten. The first evidence of a lost ancient culture in the Yangtze delta was uncovered in 1936, by Shi Xingeng, who worked at the nearby West Lake Museum in Hangzhou. He named the site Liangzhu, after a nearby town. However, the black pottery artefacts he found didn’t initially seem remarkable. It was only in the 1970s and 1980s that Liangzhu began to generate much greater excitement, beginning with the excavation of some cemeteries in and around the ancient city.

3-18-20 Coronavirus: Should you let your children play with other children?
As more and more schools close around the world, parents are wrestling with what their children can and can't do. Should your child go out and play with friends? Or does social distancing mean an end to their playtime? If Katherine Wilson could go back and change anything, she says she wouldn't have had that family dinner at the neighbours' home. Two weeks ago, when Covid-19 was spreading throughout Italy but the government had not yet mandated that people stay in their homes, the mum of two teenagers in Rome got an invitation to a small dinner party with two other families. "My husband and I thought oh we're in somebody's apartment, it's not like it's some big gathering," she tells the BBC. At the time, Ms Wilson, an American writer who is married to an Italian, says her and many other mums were treating the recent school closures as an extended holiday. "It's like: 'Oh this is great, it's kind of like a little vacation, let's go to that park we never get to go to.'" But in hindsight, after seeing how the virus has ravaged the country, she says she wishes she had been more proactive about putting limits on her family's movements. "It was kind of foolhardy to go. But it felt like saying no would have been kind of extreme." A few days later, the Italian government issued a total lockdown. That means no parks, and no playdates. "In a way the total lockdown is easier than the uncertainty of having to make decisions that were challenged by your kids, challenged by your friends," she says. "There was a good bit of judgement, both for people who were considered too extreme, and people who were considered to be taking this too lightly." Around the world, many parents are finding themselves confused like Ms Wilson was, about what the rules are for playtime and socialisation. On the one hand, governments may not have imposed lockdowns restricting people's movement. But on the other, health officials say social distancing is necessary to stop the spread of the disease.

3-18-20 Brain implant detects and turns down symptoms of Parkinson’s disease
People with Parkinson’s disease are getting brain implants that can automatically detect and reduce harmful nerve cell activity, to test if the technique could reduce movement difficulties. The device is a step up from a conventional brain implant because it is designed to reduce the side effects of this invasive treatment. Parkinson’s disease causes worsening tremors and difficulties with movement, especially when initiating actions. Medication can help, but as symptoms progress, some people have a more drastic treatment, called deep brain stimulation (DBS). This treatment works by placing wires into the skull that deliver a current to dampen down the activity in clusters of nerve cells in the centre of the brain. This can cause side effects, such as speech difficulties and jerky movements. It may be possible to minimise these side effects by delivering stimulation only when it is needed, known as responsive stimulation. Nerve cell activity can be recorded either from the same wire that delivers the current or a second one. A similar kind of brain implant is already used in a few people with severe epilepsy that is unresponsive to medicines or surgery, to reduce the excessive nerve cell activity that causes seizures. But in people with Parkinson’s it is less clear what kind of brain activity causes the different symptoms and side effects. One area of interest is the nerve cell clusters deep in the brain targeted by the brain implants. In most people, these centres sometimes fire in synchronous patterns called beta waves to signal that we should continue our present behaviour, whatever that is. “It promotes the status quo,” says Peter Brown at the University of Oxford. In Parkinson’s, there is an excess of beta waves, and this could explain why people with the condition sometimes move more slowly than they want to and have difficulties initiating new movements. So Brown and his colleagues are trying to stimulate the nerve cell clusters only when beta waves are detected.

3-18-20 How soon will we have a coronavirus vaccine? The race against covid-19
The hope is that we will have a coronavirus vaccine in 12-18 months, but for that to happen we may have to rely on untested techniques - and that comes with its own risks. POTTERING around her kitchen on the morning of 31 December, Kate Broderick scrolled through the headlines while she waited for her tea to brew. One story caught her eye: a mysterious outbreak of severe pneumonia in Wuhan, China. Nearly overnight, the number of cases seemed to explode. “I knew we didn’t have time to wait,” she says. A molecular geneticist at Inovio Pharmaceuticals in California, Broderick was poised for what came next. When Chinese officials published the genetic sequence of the new SARS-CoV-2 coronavirus causing the illness just two weeks after the first cases were reported to the World Health Organization, Broderick got to work. Within 3 hours, her team had a prototype vaccine ready for initial testing. It was an unprecedented turnaround, but a moment Broderick and many others had long seen coming. Making vaccines usually takes a decade or more between development, safety testing and manufacturing, says Seth Berkley, head of Gavi, an international group that promotes vaccine use around the world. With global confirmed cases of the new disease, covid-19, surging past 180,000 at the time of writing, time is of the essence. To speed things up, scientists are turning to untested classes of vaccines, and rethinking every part of how they are designed, evaluated and manufactured. If the approach works, we will, for the first time, have identified a new disease and developed a vaccine against it while the initial outbreak is still ongoing. But speed can come with downsides. “We could have a vaccine in three weeks, but we can’t guarantee its safety or efficacy,” says Gary Kobinger, a virologist at Laval University in Canada. The hope is to have at least 1 million doses of coronavirus vaccine available to the public in 12 to 18 months, according to Melanie Saville. She is head of vaccine development and research at the Coalition for Epidemic Preparedness Innovations (CEPI), set up in 2017 with funding from the Bill & Melinda Gates Foundation, the Wellcome Trust and several governments. Until now, the fastest we have ever cranked out a vaccine in response to an outbreak was with Ebola – and that took five years, says Berkley. Eighteen months to make a new vaccine widely available is “naively optimistic”, says Kobinger. It isn’t impossible, but it may mean ripping up the rule book.

3-18-20 People who didn’t know they had COVID-19 drove its spread in China
A new simulation shows why rapidly expanding social distancing measures are crucial. Mild cases of COVID-19 that go unrecognized are fueling the coronavirus pandemic, a new study of the early days of the outbreak in China suggests. It’s this stealth transmission from undetected cases that U.S. officials are now scrambling to limit with a slew of recently announced social distancing measures (SN: 3/13/20). On March 16, the White House coronavirus task force advised people to avoid gatherings of more than 10 people for the next 15 days. States including Pennsylvania, Ohio and New York, as well as Washington, D.C., have shut down bars and restaurants. And on March 17, a shelter-in-place order affecting close to 7 million people in the San Francisco Bay area went into effect. Similar efforts have been taken around the globe. In the new study, researchers used data on people’s movement in China from January 10 to January 23 to simulate how SARS-CoV-2, the virus that causes COVID-19, spread before restrictions on travel within the country and other isolation measures were implemented. Undocumented cases — those occurring in people with mild or no symptoms — accounted for an estimated 86 percent of all infections, the team reports online March 16 in Science. Those undetected cases were less infectious — 55 percent as infectious, the simulation found — than the known cases. But with high numbers on their side, the hidden cases became the source for almost 80 percent of the diagnosed infections. “It’s the undocumented cases that are driving the spread and growth of the outbreak,” Jeffrey Shaman, an infectious disease researcher at Columbia University, said March 16 at a news briefing. Shaman and his colleagues simulated the spread of the coronavirus with data that estimated the movement of people between 375 cities in China. The study focused on the time leading up to the Chinese New Year in late January, a period when people were traveling more and the virus moved through society relatively unimpeded before the concerted response effort.

3-17-20 Coronavirus: Will US be ready in the weeks ahead?
Covid-19's spread across the US has been on a steady rise - and the disease has yet to reach its peak stateside. What's to come in the weeks ahead? As US infectious diseases chief Dr Anthony Fauci put it recently: "It's certainly going to get worse before it gets better." Here's what public health experts have to say about what the US can expect from the coronavirus. Dr Gregory Poland, director of Mayo Clinic's Vaccine Research Group, says analysing a new disease is like looking at a pixelated image - when you've only rendered 30%, it's impossible to tell what the photo is. Once you load 70%, the picture gets clearer, and so on. "We're in that 30 to 50%," Dr Poland says of Covid-19. "There's a lot we genetically know about coronaviruses [and] a huge amount we don't know, clinically, epidemiologically and seasonally with regards to this virus." Worst case, Dr Poland says, based on early models, between 40 to 70% of the US will be infected. That's between 132 and 231 million people. One factor to consider is how Covid-19 is mutating - at a rate about once every other week. Dr Poland says it could be turning less virulent, as happens with other similar viruses. The present fatality rate in the US is around 0.03%, he notes, which appears less than what was observed in China. Dr Poland says the next best case scenario is that doctors figure out an existing antiviral can be used to treat Covid-19. Otherwise, hopefully within the next year, scientists can develop a vaccine or other treatment therapy. "Worst case, none of those happen in a timely manner," he says. "If we don't do anything? Assuming a case fatality rate of 0.1 or 0.3% - that's tens of thousands of deaths. Hundreds of thousands possible hospitalisations." Even if Covid-19 drops to the level of the seasonal flu, if 40-70% people are infected, it will still cause a high number of deaths and hospital stays, especially among those 60 and older. "These next couple of weeks are really going to be critical. Are we going to start seeing a tip over into widespread community transmission or is it going to be relatively slow? I think these next few weeks are critical and all of us in this field are holding our breath to see what happens." Dr Poland says based on the history of similar diseases, Covid-19 may dampen or entirely disappear in the heat of summer, like SARS did in 2003. If not, it will probably circulate until it exhausts most susceptible people. "It really is speculation," he emphasises. "What happens in China is not necessarily generalisable to the US culture, and you make your best case and try to add data point-by-point to the pixelation."

3-17-20 Coronavirus: Cambridge scientists race for a vaccine
Scientists at the University of Cambridge say they are working "as hard and as fast as we possibly can" to find a vaccine to stop the spread of coronavirus. Prof Jonathan Heeney spoke to BBC science correspondent Richard Westcott at a laboratory in the city, with access so restricted he had to talk through a glass window. "It's a complex process. Right now we have our vaccine candidates in mice and they're generating immune responses to the vaccine," said Prof Heeney. "We're working around the clock with a team of experts and everybody's collaborative. The sooner we can get a vaccine or therapy out there the better."

3-17-20 Analysis suggests UK still not doing enough to prevent covid-19 deaths
The UK is introducing stronger measures to tackle the spread of the coronavirus, but some of the science that helped to inform this approach suggests it still won’t be enough to avoid a large number of deaths. Yesterday, UK prime minister Boris Johnson said people should stop all unnecessary travel, and work from home if possible. He said pubs, clubs and other social spaces should be avoided and whole households should self-isolate for 14 days if any individual in it develops covid-19 symptoms. People who may be particularly vulnerable to the virus may soon be asked to stay home for 12 weeks. These new policies were informed at least in part by research that modelled the potential of various public health measures to keep a lid on the spread of the virus until a vaccine is available, which may still be 18 months or more away. “Our main focus is to understand, at this current time, what are the potential impacts of various measures,” says Azra Ghani at Imperial College London, who discussed the report at a press conference on Monday. There are two basic strategies available for tackling the coronavirus: mitigation, which aims to slow but not necessarily stop the epidemic, and suppression, which aims to reduce transmission to a minimum and keep it that way so that the epidemic dies out. Suppression is the best option for public health but is extremely difficult to achieve and maintain. “This has never been tried anywhere ever,” says Tim Colbourn at University College London. “Can it work?” Ghani and her colleagues calculated that mitigation, which reduces the demand on health services and can help protect vulnerable people, would still overwhelm the health system and lead to an estimated 250,000 deaths in the UK, about half of the number that would occur with no control measures. She describes this as “probably still an unacceptable level of burden”. Nonetheless, the UK government still seems to be leaning towards mitigation, rather than suppression, for now. The modelling shows that suppression would require a bare minimum of three measures: home isolation of all cases for seven days, quarantining of all their household members for 14 days, and population-wide social distancing. This is defined as a 75 per cent reduction in social contact outside home, school or work. “The sorts of contacts one makes in pubs, theatres, restaurants,” says Ghani.

3-17-20 ‘Bonehenge’: Stone Age structure of mammoth bones discovered in Russia
A prehistoric circle made almost entirely of mammoth bones has been found in Russia. The “bonehenge” was built near the peak of the last glacial period, but it isn’t clear why. Stone Age people made many bone circles in eastern Europe and northern Asia in the last 22,000 years. One of the best-known sites is Kostenki 11, south of Voronezh in Russia. Two circles of mammoth bones were found there in 1951 and 1970, and have been studied ever since. Then in 2014 a third circle was found. Alex Pryor at the University of Exeter in the UK and his colleagues have now investigated it. The circle is about 12.5 metres across. Mammoth bones have been piled up to form a wall 1 to 2 metres thick, with no obvious entrance. We can’t be sure how tall the wall was, says Pryor, but “my hunch would be no more than, say, 50 centimetres high”. The internal space was about 8 metres across. The circle is about 20,000 years old, according to studies that dated the bones. At that time, ice sheets had advanced far to the south and the local climate was harsh. Bone circles at other sites have been interpreted as dwellings. “The way these things have sometimes been reconstructed is with a whole framework of mammoth bones, used to weight down hide roofs with some kind of wooden supports,” says Pryor. However, Pryor says that is unlikely in this case. The internal space is so large, it would be difficult to build a roof with prehistoric materials. “In the museum in Kiev, they’ve tried to build a reconstruction of one of these things, and they had to use steel girders,” he says. Also, people only seem to have used the circle intermittently. It may have been used for processing food – perhaps tuber vegetables, similar to parsnips, that could survive in the frigid climate. The team has found charcoal from fires, flakes of rock produced when stone tools are repaired, and plant remains within the circle.

3-17-20 This is one of the largest Ice Age structures made of mammoth bones
Hunter-gatherers in what’s now Russia constructed the massive ring around 25,000 years ago. Ancient people took on a mammoth project, in more ways than one. Excavations at Russia’s Kostenki 11 site have uncovered one of the oldest and largest Ice Age structures made of mammoth bones. Hunter-gatherers assembled bones from at least 60 mammoths into an imposing ring around 25,000 years ago, say archaeologist Alexander Pryor of the University of Exeter in England and colleagues. Building this structure, which measures about 12.5 meters across, required a huge investment of time and energy, the scientists report in the April Antiquity. Bones may have come from hunted mammoths or from carcasses of animals that died of natural causes. Sieving of soil samples identified charred wood from fires set inside the ring, but it’s unclear how its makers used the structure, Pryor’s team says. Circular mammoth bone structures, most dating to no more than 22,000 years ago, previously have been found across eastern Europe and western Russia (SN: 12/13/86). Researchers have often assumed that these constructions, including two others found at Kostenki 11 in the 1950s and 1960s, housed people during harsh winters. The new discovery challenges that idea. A large, open space in the bone ring appears unsuitable for long-term occupation, in part because it would have been difficult to roof, Pryor’s group says. And only a few stone tools were found. Ice Age hunter-gatherers may have stored food or conducted ritual ceremonies in their mammoth creation, the researchers speculate.

3-16-20 All the reasons why organic food doesn’t deserve such bad press
Negative headlines about organic farming’s carbon footprint are missing the bigger picture about its environmental benefits, say Christel Cederberg and Hayo van der Werf. People are keener than ever to make ethical, environmentally friendly food purchases. But a spate of bad press about the environmental impact of organic produce may leave some people scratching their heads. The debate about this is contentious. Critics say organic farming is less efficient than conventional farming, and so uses more land, leading to greater deforestation, which causes higher carbon dioxide emissions and biodiversity loss. A recent paper followed this logic to find that going 100 per cent organic in England and Wales would raise these emissions by up to 56 per cent. The claim made headlines. But the findings from this study and similar ones are too simplistic and ignore important positive aspects of organic farming. We have analysed such studies and found that the method they often use doesn’t give the full picture. Known as a life cycle assessment (LCA), this approach simply relates environmental impacts to the amount of product harvested from a given area of land. Looked at this way, intensive farming is often more efficient, since its yields are higher. But this doesn’t properly address all environmental aspects. Such assessments fail to fully account for the role of land degradation, biodiversity decline and pesticide impacts of intensive agriculture. Consider biodiversity, for example. The variety of life on Earth is an incredibly important factor in the health and resilience of ecosystems. But worldwide, it is in decline – insect and bird populations are being decimated, something that has been repeatedly linked to the damaging practices of intensive farming. Organically managed land, however, has been shown to support biodiversity levels around 30 per cent higher than conventionally farmed fields.Q

3-16-20 Coronavirus: Why we touch our faces and how to stop it
Several medical officials across the world have warned people to avoid touching their face as a key way to prevent the spread of coronavirus. Often when issuing the warning, they've gone on to - you guessed it - put their hands on their face. But why do we touch our faces in the first place? And is it that easy to just stop doing it all of a sudden?

3-16-20 Coronavirus: What we know so far about risks to pregnancy and babies
Pregnant people don’t seem to be at greater risk of experiencing severe covid-19, and the virus doesn’t seem to pass to fetuses, but there’s still a lot we don’t know. As cases of covid-19 continue to multiply around the world, we are all being advised to take precautions to avoid getting infected, whether that is singing your favourite 20-second tune while washing your hands, avoiding non-essential travel or working from home. But what about people who are pregnant? And are their babies at risk? So far, information is relatively scant. Pregnant people in China who are diagnosed with the coronavirus are treated in designated hospitals, and the handful of published reports of such cases only cover tens of people. However, initial reports suggest that covid-19 might not hit pregnant women or their newborn babies too heavily. One reason to worry about covid-19 in pregnancy is that people are more likely to become severely ill with flu when they are pregnant. That is partly because pregnancy suppresses a person’s immune system. Additionally, in the later stages of pregnancy, the fetus and uterus can start squashing other organs, including the lungs. As a result, some areas of the lungs become less able to circulate air, leaving them more prone to infection. Some kinds of infection also seem to put the fetus at risk. Prolonged, high fevers in pregnancy, particularly in the first trimester, have been linked to some birth defects. “With any viral infection during pregnancy, the fetus is at risk of miscarriage, stillbirth, growth restriction, malformation,” says David Baud at Lausanne University Hospital in Switzerland. There is some evidence that pregnant women are more at risk of serious illness from MERS and SARS – viruses that are similar to the new coronavirus – and that these infections also increase the risk of miscarriage. But it is difficult to say for sure though, because only a handful of pregnant people have been reported to be infected with those viruses, and miscarriages occur in about a quarter of all pregnancies.

3-16-20 Type 1 diabetes may be two conditions that need different treatments
Diabetes is generally thought to come in two forms: type 1 and type 2. But a study suggests type 1 diabetes could be two separate conditions, meaning there are more forms than we realised. People with diabetes tend to have high blood sugar levels. This is because they either lack or don’t respond to insulin, a hormone that allows sugar to be taken up by our cells and either converted to energy or stored. Those who have type 1 diabetes develop it because their immune system attacks the cells in the pancreas that make insulin. The age at which a person is diagnosed with type 1 diabetes seems to be linked to the severity of their symptoms. “A child diagnosed before the age of 5 is likely to have a more severe form of disease than someone over 30,” says Sarah Richardson at the University of Exeter, UK. To find out why, Richardson and her colleagues looked at 32 pancreas samples from young people with diabetes who died in the 1950s. They found two distinct categories. In one, some pancreases didn’t appear to make insulin properly and experienced a stronger immune system attack. In the other category, the pancreas samples contained fewer immune cells and there were also signs that they were better at making insulin. The immune attack appears totally different in these two categories, says Richardson. The researchers then looked at blood samples taken from 171 people who had been diagnosed with type 1 diabetes before they turned 30. They found the same pattern: people seemed to fall into one of the two categories, depending on how well their pancreases made insulin. These categories seem to correspond with age. People whose type 1 diabetes involved poor insulin production and a stronger immune attack tended to be younger, says Richardson. Her team calls this group “endotype 1”. In the study, “pretty much everyone under the age of 7 falls into this category”, says Richardson.

3-14-20 Coronavirus is most contagious before and during the first week of symptoms
People stop making infectious virus once the body’s antibody response kicks in. As sweeping efforts to contain the COVID-19 pandemic go into effect around the globe, researchers are starting to get hints of just when patients are most contagious. People infected with the SARS-CoV-2 virus, which causes the disease, may test positive for the virus both before and after they have symptoms. But a new study of nine people who contracted the virus in Germany suggests that people are mainly contagious before they have symptoms and in the first week of the disease. Infectious viruses were isolated from about 17 percent of nose and throat swabs and more than 83 percent of phlegm samples during that first week, researchers report March 8 in a study posted at medRxiv.org. Patients produced thousands to millions of viruses in their noses and throats, about 1,000 times as much virus as produced in SARS patients, Clemens Wendtner, director of infectious disease and tropical medicine at Munich Clinic Schwabing, a teaching hospital, and his colleagues found. That heavy load of viruses may help explain why the new coronavirus is so infectious. Scientists identified these nine people some time after they had been exposed to the coronavirus, so researchers don’t know for sure when exactly people begin giving off virus. After the eighth day of symptoms, however, the researchers could still detect the virus’s genetic material, RNA, but they could no longer find infectious viruses. That’s an indication that antibodies that the body’s immune system makes against SARS-CoV-2 are killing viruses that get out of cells, Wendtner says. The study brings an important point to light; finding RNA or pieces of a virus in a swab or sample is no guarantee that the virus is “live,” or infectious, says Ali Khan, dean of the College of Public Health at the University of Nebraska Medical Center in Omaha. “Some of it is discouraging news because when you are mildly [ill] or just [getting] sick, you’re putting out a whole lot of virus, which explains why we’re seeing so much transmission within our communities,” says Kahn, was not involved in the study.

3-14-20 Social distancing, not travel bans, is crucial to limiting coronavirus’ spread
Acting now to reduce the virus’ spread will help avoid worst-case scenarios. Aggressive actions to prevent — or at least to slow — the spread of COVID-19 are being taken across the world. Universities are cancelling in-person classes, while academic conferences and political rallies are postponed. Shops are shuttering. Sports leagues are suspending seasons or competing in empty stadiums. Such “social distancing” measures, as they are called by public health experts, are considered essential in controlling a viral pandemic (SN: 3/11/20). What’s not helpful at this point is banning travel from other affected countries, experts say, such as the U.S. ban on most European visitors announced March 11 by President Donald Trump. “I recommend that people voluntarily cut back on non-essential travel” — a form of social distancing in that people would be avoiding crowded airports, train stations and bus depots, says Caitlin Rivers, an epidemiologist at the Johns Hopkins Center for Health Security. “But I do not expect that travel bans will meaningfully impact the trajectory of the outbreak.” The virus is probably more widespread than we realize in the United States, partly because early problems with testing meant cases likely slipped by undetected (SN: 3/6/20). So U.S. health officials are most concerned now with limiting opportunities for transmission. That helps to prevent hospitals and clinics from becoming overwhelmed, as reportedly has happened in Italy as the number of confirmed cases shot beyond 10,000 in just two weeks. Acting quickly to establish social distancing measures can “flatten the epidemic curve” of an outbreak, experts say. That means the outbreak spreads more slowly and reaches its peak later, with a lower number of active cases at the peak than if no preventive measures were taken.

3-14-20 ‘Human Nature’ offers CRISPR novices a basic introduction
A new documentary leaves out some aspects of the gene-editing technology. Humans have been tinkering with the genes of plants and animals through selective breeding for millennia. But the ability to change our own DNA is something very new. The gene-editing tool CRISPR offers the promise of correcting genetic typos that cause a range of diseases. The documentary Human Nature — which opened in select U.S. cities on March 13, with more to follow — introduces viewers to the technology. Graphics, archival footage and beautiful imagery help explain how scientists took a DNA-cutting enzyme and its guide molecule, which form the basis of bacterial immune systems, and transformed them into CRISPR/Cas9, often just called CRISPR. Pioneers of the technology, including Jennifer Doudna, Feng Zhang, George Church and Emmanuelle Charpentier, recount serendipitous discoveries and hard-won insights in the tale of CRISPR’s development over several decades. At the heart of the film is an ethical discussion of whether to allow scientists to use CRISPR to make changes in eggs, sperm or embryos that could be inherited by future generations. In one scene, Russian President Vladimir Putin tells a group of young people that using CRISPR to make designer people could be more dangerous than the nuclear bomb. In a counterpoint, bioethicist Alta Charo of the University of Wisconsin Law School in Madison says such fears may be overblown. The film is wide-ranging, but with a few glaring omissions. Most notably, in 2018, Chinese researcher Jiankui He announced that human babies had been born from CRISPR-edited embryos (SN: 12/22/18 & 1/5/19, p. 20). That announcement touched off a firestorm of controversy and debates among scientists about whether a self-imposed moratorium on heritable editing should be enacted. In December 2019, He was sentenced to three years in prison for forging documents to make it look as if he had approval from an ethics review board to do the work. The film’s only reference to the event is a title card at the end that briefly lays out what happened and states, “It marked the first time in history that humans edited the genetic code of a future generation. This controversial experiment has intensified the global debate about where we, as a species, should draw the line.”

3-14-20 A trick from cancer cells helps rats accept transplanted limbs
Crucially, the technique doesn’t rely on medications that suppress the immune system. To help rats adopt transplanted limbs as their own, researchers have harnessed a ruse that cancer cells use to hide from the immune system — effectively reprograming the animals’ defenses to ignore foreign tissue. Rats injected with engineered microparticles tolerated a hind limb transplant from another rat for more than 200 days, even in the absence of drugs that suppress immune responses, researchers report March 13 in Science Advances. When injected into the transplanted tissue, the microparticles release a signaling protein known as CCL22 that’s secreted from cancer cells and attracts specialized immune cells. These immune cells, called regulatory T cells, can mark the rat’s new tissue as “self” and protect it from an onslaught of immune defenses that would normally attack foreign material. The microparticle treatment is “fundamentally different than anything that is used right now in clinical medicine simply because it doesn’t suppress the animal’s immune system,” says James Fisher, a bioengineer at the University of Pittsburgh. Patients who receive donor organs or tissues typically spend the rest of their lives taking medication that dampens their immune responses. Without drugs, the immune system would attack and reject the donor tissue, unless it is a perfect genetic match, causing the transplant to fail. But long-term regimens of immunosuppressive drugs can put patients at risk for things like infectious disease or cancer (SN: 10/21/18). Another approach could be to keep immune responses intact while also shielding new tissue — such as stealing techniques that cancer cells use to evade detection. Inspired by therapies designed to block cancer’s strategies for concealment, “the thought came into my head: I wonder if we were able to synthetically mimic [what cancer cells do], could we trick the body into accepting a transplant?” says Steven Little, a chemical engineer at the University of Pittsburgh.

3-14-20 An ancient ball court sheds light on a game made famous by the Aztecs
A mountain site in Mexico suggests an ancient ball game didn’t originate in coastal lowlands. A roughly 3,400-year-old ball court in the mountains of southern Mexico has scored surprising insights into a game that later played a big role in Maya and Aztec societies. Excavations at a site called Etlatongo revealed the ancient ball court — the second oldest found to date. The discovery shows that, at a time when societies in Mexico and Central America were growing larger and more politically complex, population centers in the mountains contributed to ball court design, and possibly to early rules of the game, researchers report March 13 in Science Advances. Until now, most evidence pointed to coastal settlements in southern Mexico’s Gulf and Pacific lowlands as the developers of a ball game that assumed ritual and political importance throughout the region. “Multiple regions and societies were involved in developing a blueprint for the ball court used in a formal ball game across Mesoamerica,” says anthropological archaeologist Jeffrey Blomster of George Washington University in Washington, D.C. Mesoamerica was an ancient cultural region running from central Mexico through much of Central America. More than 2,300 probable ball courts have been found at Mesoamerican sites. Many come from centers that date to between around 1,800 and 1,100 years ago during the Classic Period of the Maya empire, as well as from the Aztec empire, which lasted from about 675 to 500 years ago. “The discovery of a formal ball court [at Etlatongo] … shows that some of the earliest villages and towns in highland Mexico were playing a game comparable to the most prestigious version of the sport known as ullamalitzli some three millennia later by the Aztecs,” says Boston University archaeologist David Carballo. Crowds of spectators at Aztec ball games sometimes watched politically tense contests between teams from rival kingdoms, as well as games punctuated by human sacrifices.

3-13-20 Thirdhand smoke exposure
Nonsmokers who carefully avoid going anywhere where people light up can still be exposed to the negative health effects of cigarette smoke, warns a new study from Yale University. It found that chemicals from tobacco smoke can infiltrate nonsmoking rooms by hitching a ride on smokers’ clothes, skin, and hair and then evaporating into the air. To discover how so-called thirdhand smoke can spread, the researchers put an air-sampling device in a cinema that has enforced a smoking ban for 15 years—long enough for any pre-ban contaminants to have cleared out. Over four days, they observed sharp spikes in 35 tobacco-related chemicals—including cancer-causing compounds such as benzene and formaldehyde—when audience members entered the theater. Although the room was well-ventilated, by the end of the movie patrons had breathed in the equivalent of the secondhand smoke from up to 10 cigarettes. Lead author Drew Gentner tells Agence France-Presse that he hopes the study “will generate much-needed discussion about thirdhand smoke.”

3-13-20 Our ancestors may have run a million years earlier than we thought
The ancient human species Australopithecus afarensis may have been the earliest hominin to run on two legs. Although it had relatively short, ape-like legs, A. afarensis may have had a long Achilles’ tendon just like modern humans do – a feature that helps us to run more efficiently. Conventional thinking is that early hominins like A. afarensis – the species to which the famous Lucy fossil belonged – learned to walk long before they could run. Lucy was an ape-like bipedal hominin sometimes seen as a likely direct ancestor of the earliest species of human. Some evidence places the origin of bipedal walking more than 10 million years ago. But many researchers think it was only with the appearance of the human genus Homo, between 2 and 3 million years ago, that hominins began to run. Ellison McNutt at the University of Southern California thinks the story is more complicated than that. Some earlier hominins should have had some ability to run when faced with a predator, for instance. McNutt looked for evidence of running ability in A. afarensis, because this species appeared about 3.9 million years ago and disappeared a million years later, about the same time as the first humans, such as Homo habilis, evolved. She and Jeremy DeSilva at Dartmouth College in New Hampshire focused on the Achilles’ tendon, a band of tissue connecting the calf muscles to the heel. Modern humans have a long Achilles’ tendon that extends more than halfway up our lower leg. It stretches when we run to store elastic energy that it then releases explosively. This helps us to save as much as 35 per cent of the energy we use when running. “A long Achilles’ tendon is helpful for efficient walking, but it is especially critical for efficient running,” says McNutt.

3-13-20 Was Earth a water world?
Our blue planet may have been a whole lot bluer some 3 billion years ago, devoid of continents and almost entirely covered by a global ocean. That’s the conclusion of a new study that examined an ancient chunk of ocean-bed crust that now sits on its side in the Australian outback. The researchers examined the levels of two different isotopes of oxygen that seawater carried into the slab: Oxygen-16 and the slightly heavier atom Oxygen-18. After studying more than 100 rock samples, they determined that seawater contained more Oxygen-18 when the crust was formed 3.2 billion years ago. Today, land masses across Earth soak up heavier oxygen isotopes from water and lock them in clay-rich soils. The scientists suspect that the ancient ocean crust contains higher levels of Oxygen-18 because there were no soil-covered continents to absorb it. Study co-author Boswell Wing, from University of Colorado, Boulder, tells CNN.com that “teeny micro-continents” that resembled the Galapagos Islands might have stuck out of this ancient ocean. “We just don’t think that there was global-scale formation of continental soils like we have today.”

3-13-20 Every Arabica coffee plant may come from a single common ancestor
DNA sequencing has confirmed that a lot of the coffee you drink is from one of the least genetically diverse crops in the world, making it particularly vulnerable to extinction. Arabica beans (Coffea arabica) make up about 60 per cent of the world’s coffee production. “Arabica is the most valuable and highest quality coffee, but it is severely endangered by climate change,” says Simone Scalabrin at IGA Technology Services in Italy. Scalabrin and his colleagues used whole genome sequencing to look at 736 samples of Arabica plants from Ethiopia and Yemen which had been stored in a coffee conservation centre in Costa Rica. We already knew that the Arabica genome is the result of the fusion of two species, C. canephora and C. eugenioides, but we didn’t know if the Arabica we consume today is from this event occurring several times, or just once. The researchers found that the genetics of the various samples of Arabica they looked at were more than 99.9 per cent similar. This low genetic diversity suggests these plants are the result of a single random hybridisation event. While the event may have occurred more than once, this analysis suggests only one of these lineages survived, which means that every Arabica plant today has a common ancestor – probably around 10,000 to 20,000 years old. “It is one of the least genetically diverse plants in the world,” says Scalabrin, and this makes it particularly vulnerable to climate change, pests and disease. “Now is the time for breeding, breeding, breeding,” says Scalabrin. Aaron Davis at the Royal Botanic Gardens in London says that this study strengthens the argument for developing a new generation of coffee crops. “But the difficulty with cross-breeding is ensuring that the coffee retains its taste,” he says.

3-13-20 Social distancing, not travel bans, is crucial to limiting coronavirus’ spread
Acting now to reduce the virus’ spread will help avoid worst-case scenarios. Aggressive actions to prevent — or at least to slow — the spread of COVID-19 are being taken across the world. Universities are cancelling in-person classes, while academic conferences and political rallies are postponed. Shops are shuttering. Sports leagues are suspending seasons or competing in empty stadiums. Such “social distancing” measures, as they are called by public health experts, are considered essential in controlling a viral pandemic (SN: 3/11/20). What’s not helpful at this point is banning travel from other affected countries, experts say, such as the U.S. ban on most European visitors announced March 11 by President Donald Trump. “I recommend that people voluntarily cut back on non-essential travel” — a form of social distancing in that people would be avoiding crowded airports, train stations and bus depots, says Caitlin Rivers, an epidemiologist at the Johns Hopkins Center for Health Security. “But I do not expect that travel bans will meaningfully impact the trajectory of the outbreak.” The virus is probably more widespread than we realize in the United States, partly because early problems with testing meant cases likely slipped by undetected (SN: 3/6/20). So U.S. health officials are most concerned now with limiting opportunities for transmission. That helps to prevent hospitals and clinics from becoming overwhelmed, as reportedly has happened in Italy as the number of confirmed cases shot beyond 10,000 in just two weeks. Acting quickly to establish social distancing measures can “flatten the epidemic curve” of an outbreak, experts say. That means the outbreak spreads more slowly and reaches its peak later, with a lower number of active cases at the peak than if no preventive measures were taken.

3-12-20 Why don't children seem to get very ill from the coronavirus?
It has been widely reported that children are less likely to get severely ill and die from the new coronavirus. A recent study of 44,672 people with confirmed covid-19 infection found that children under 10 years old made up less than 1 per cent of those cases and none of the 1023 deaths. “This is unlike flu,” says Akiko Iwasaki at Yale University. With flu, young children and older people are usually the most severely affected, so why is the new coronavirus different? It is a bit of a mystery. A straightforward explanation would be that children are resisting infection in the first place, but that doesn’t seem to be the case. One recent study even found children to be just as likely as adults to get infected. In any case, children that do become infected are still less likely to get sick with covid-19 and die – a similar trend to that seen with SARS or MERS, two other severe diseases caused by coronaviruses. So, what is protecting children? “No one has a good answer to that question yet,” says Iwasaki. But she and other experts suspect it may be down to the unique way children’s immune systems respond to these viruses. A common complication of covid-19, SARS and MERS in adults is acute respiratory distress syndrome, where the immune response against the coronavirus becomes overzealous and causes life-threatening damage to the lungs. The resulting leakage of fluid and immune cells into the lungs causes big problems, says Chris van Tulleken at University College London. Even if those immune responses are trying to help by attacking the virus, they can end up blocking oxygen uptake in the lungs, he says. Because children’s immune systems are still developing, one suggestion is that they are shielded from this type of dangerous immune response – called a cytokine storm – when they get covid-19 or similar diseases. During the SARS outbreak, two studies found children produced relatively low levels of inflammation-driving cytokines, which may have been what protected their lungs from serious damage.

3-12-20 Rates of death after stroke have fallen by a quarter in south London
Strokes are becoming less deadly, at least in one part of the UK. Rates of death and disability caused by a stroke have dropped by nearly a quarter in the past sixteen years in south London. The change is probably due to faster hospital treatment, such as patients getting clot-busting drugs in the first few hours and better longer-term care and rehabilitation, says Yanzhong Wang at King’s College London. Wang’s team looked at figures for people living in south London who had an ischaemic stroke, which is caused by a blood clot blocking an artery to the brain; it is responsible for nine out of ten cases of stroke. In 2015, 20 per cent of people who had this kind stroke died within a year, and 27 per cent of the total ended up classed as disabled in some way, such as being left unable to talk or walk. But this was an improvement on figures from 2000, when the rate of death was 33 per cent and rate of disability was 35 per cent. In the past decade the UK has run nationwide campaigns to make people aware of the signs of a stroke, such as sudden speech problems or the face drooping on one side. If people get to hospital within about four hours of these symptoms they can be given a drug to break up the clot. A few may have surgery to physically destroy it. And since 2010 London has started treating more people in specialist stroke centres, where people are more likely to get these emergency treatments in time, and to go on long-term blood-thinning medicines, than if they are taken to their nearest hospital. The National Health Service plans to roll out more specialist stroke centres across the country. But another contributing factor could be that more minor strokes are being diagnosed, says Wang.

3-12-20 Plants sprouted from seeds stored for decades in a disused Arctic mine
Several hundred metres down the dark, cold tunnel of an Arctic coal mine, a passageway leads off to a wooden door adorned with the image of a Nordic goddess of fertility, which guards precious treasure. There, in 1986, the seeds of 17 crops were put in a metal container in 1986, in order to see how well the permafrost would preserve them far into the future. The first results are mixed for the 100-year seed project – a precursor to the nearby Svalbard Global Seed Vault on Norway’s island of Spitsbergen, it aims to discern how seeds will fare after a century of being tucked away. Peas, wheat and rye were among the species stored in coal mine three, one of six former mines around the town of Longyearbyen. In the chamber where the seeds lie beneath rafters encrusted with ice, the coal seam is visible, but it hasn’t been exploited for more than two decades. Åsmund Asdal at crop diversity institute NordGen says regular tests of the seeds have been recorded by pen and paper and left inside the boxes since 1986, so that future generations can continue in the same vein. The seeds’ ability to germinate changed little in the first 20 years. “But we have had a significant drop for the last 10 years,” he says. The seeds are all from crops that are important for food in the Nordic region, and they were stored at temperatures of around -3°C, maintained by the permafrost around the mine. This is a lot warmer than the -18°C that seed banks usually maintain. After 30 years, 9 of the 17 crops had retained more than 90 per cent of their initial capacity to germinate. Yet while barley was at a healthy 89 per cent, rye fell to 49 per cent. Because drying is an important part of the seed-banking process, Asdal says it is unsurprising that the seeds with the highest moisture content showed the largest drops in germination.

3-12-20 This ancient dinosaur was no bigger than a hummingbird
A skull from one of these Mesozoic Era birds was found encased in a chunk of amber. A tiny, toothed bird that lived 99 million years ago appears to be the smallest known Mesozoic dinosaur, an era from about 252 million to 66 million years ago. The creature’s 12-millimeter-long skull was found encased in a chunk of amber originally discovered in northern Myanmar, researchers report March 11 in Nature. Of modern birds — the only dinosaurs still living today — the bee hummingbird is the smallest. The new species, dubbed Oculudentaviskhaungraae, was similar in size. But three-dimensional images of the fossilized skull created with computed tomography, a type of X-ray imaging, revealed that the Mesozoic bird had little else in common with today’s nectar-sipping hummingbirds. Instead, the images reveal a surprising number of teeth, suggesting the little bird was a predator, the researchers report. “It had more teeth than any other Mesozoic bird, regardless of size,” says paleontologist Jingmai O’Connor at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing. As for its prey, researchers can only guess, she adds. O. khaungraae probably dined on arthropods and invertebrates, and possibly even small fish. The ancient bird also had deep, conical eye sockets, similar to those of modern predatory birds such as owls. Those deep sockets can increase the eye’s visual ability without increasing its diameter, and suggest the ancient birds had sharp eyesight, O’Connor says. But while owls’ eyes face forward, increasing their depth perception, the eyes of the tiny bird faced out to the side. The creature may have been the product of evolutionary miniaturization, whereby animals evolve smaller adult body sizes. There are limits to how small an animal can get. “You have all these restrictions related to trying to fit sensory organs into a small body size,” O’Connor says.

3-11-20 Smallest dinosaur found 'trapped in amber'
Scientists have discovered what they say is the smallest known dinosaur. The new species has been described by one team member as the "weirdest fossil" she has ever worked on. The specimen, from northern Myanmar, consists of a bird-like skull trapped in 99-million-year-old amber. Writing in the prestigious journal Nature, researchers report that the dinosaur would have been similar in size to the bee hummingbird - the tiniest living bird. The stunning find may shed light on how small birds evolved from dinosaurs - which were often bigger. While the smallest dinosaurs, such as the bird-like Microraptor, weighed hundreds of grams, the bee hummingbird weighs just 2g. "Animals that become very small have to deal with specific problems, like how to fit all sensory organs into a very small head, or how to maintain body heat," said Prof Jingmai O'Connor from the Chinese Academy of Sciences in Beijing. The new species, dubbed Oculudentavis khaungraae, appears to have dealt with these challenges in unusual ways. For example, the animal's eye structure surprised the scientists. Birds have a ring of bones, the scleral ring, that helps to support the eye. In most birds, the individual bones, called scleral ossicles, are simple and fairly square. But in Oculudentavis, they are spoon-shaped, a characteristic previously only found in some living lizards. The bones of the eye would have formed a cone, like the eye bones in owls. This indicates that the dinosaur had exceptional vision. Unlike owls, the eyes faced sideways and the opening at the centre of the ossicles was narrow, which would have restricted the amount of light coming into the eye. This provides strong evidence that Oculudentavis was active in the daytime. In addition, the creature's eyes would have bulged out of its head in a manner not seen in any other living animal, making it hard to understand exactly how the eyes functioned. "It's the weirdest fossil I've ever been lucky enough to study," Prof O'Connor explained. "I just love how natural selection ends up producing such bizarre forms. We are also super lucky this fossil survived to be discovered 99 million years later."

3-11-20 Tiny birdlike dinosaur species identified from skull trapped in amber
“I WAS blown away when I first saw the skull, it’s so well preserved and so damn weird,” says Jingmai O’Connor at the Chinese Academy of Sciences. “I knew it was so rare.” This birdlike dinosaur was discovered in northern Myanmar and has been analysed by O’Connor and her colleagues. It is 99 million years old and the smallest dinosaur ever found from the Mesozoic era. CT scans revealed that the creature, named Oculudentavis or “eye tooth bird”, had bulging eyes and sharp teeth (Nature, DOI: 10.1038/s41586-020-2068-4). Its narrow eye sockets would only have let in limited light, suggesting it was most active during the day. The skull measures just 1.4 centimetres across, indicating it may have been smaller than any bird living today, but the jaw shape suggests it had a powerful bite. “It was probably smaller than the bee hummingbird,” says O’Connor.

3-11-20 Covid-19: The science of uncertainty can help us make better choices
As the coronavirus outbreak continues, why do some people stockpile and others shrug? The psychology of uncertainty explains what's going on, says Rachel McCloy. MANY people seem to be dealing with the recent coronavirus outbreak in one of two ways: by panicking or shrugging. There is a great degree of uncertainty around how bad the epidemic will get, which means it is easy to over or underreact and make the wrong choices. By understanding the psychology behind what is going on, it is possible to find the elusive middle ground of worry. When we face uncertainty about the future, events can feel like they are out of our control. This often triggers negative emotions, such as fear and anger – emotions that we are motivated to try to reduce. However, when it comes to the coronavirus crisis, the actions we take to regain a sense of control tend to be the least effective for controlling the virus. Panic buying large quantities of food and cleaning products is an example of this. Not only may this do more harm than good by creating a shortage in the supermarkets, as is happening with toilet roll, it distracts from more effective steps people could take. Another measure that may increase our sense of perceived control more than is warranted is the wearing of face masks by healthy individuals. The masks themselves only protect from infection when fitted perfectly, and can also have unfortunate consequences. People tend to touch their faces more than usual when wearing face masks in order to adjust them, which may give the virus an alternative way into their bodies, such as through their eyes. Mask-wearing may also cause people to feel more confident that they will avoid infection. This over-optimism bias makes them more likely to engage in social contact, increasing their chances of exposure. More appropriate things to do from a public health point of view are simple infection control actions, such as frequent and careful handwashing, general good hygiene and self-isolating if you start to show cold-like symptoms. Unfortunately, these seem to have much less of an effect on our perceived sense of control.

3-11-20 Why the coronavirus is different from flu and warrants major action
People who argue that covid-19 is no bigger a problem than flu ignore the fact that we lack natural immunity and have no vaccines in our armoury. FOR weeks now, the news has been dominated by the coronavirus. This is hardly surprising: it is an unprecedented global story with an unknown ending, featuring a new virus we don’t yet fully understand. The planet’s most populous nation shut down an entire province to try to contain it, and now there is an exponential uptick in cases worldwide. It is also no wonder everyone is talking about the virus, given many people are worrying about the risks to themselves or their loved ones. No wonder, too, that inaccurate articles and even conspiracy theories are flourishing, and that warnings to be ready for self-isolation have led to panic-buying. Inevitably perhaps – with the numbers of diagnosed cases currently still low in many countries – a backlash is under way. There is a view that the fatality rate will turn out to be tiny, that the new virus is no more noteworthy than flu and that the economic harm of containment measures doesn’t justify the lives they could save. The media, meanwhile, is being accused of stoking panic in its reporting. But as Michael Leavitt, a former US secretary of health, put it last week: “Anything said in advance of a pandemic seems alarmist. After a pandemic begins, anything one has said or done is inadequate.” The best information now available suggests a fatality rate of around 0.7 per cent (see “Why is it so hard to calculate how many people will die from covid-19?”), which means the covid-19 virus has the potential to kill a large number of people worldwide. The virus differs from flu in that there is no widespread immunity to it – the only people likely to have any are those who have already had it. What’s more, unlike flu, we have no vaccines to give to those who are most at risk.

3-11-20 Why the health benefits of cycling to work outweigh the risk of injury
People who cycle to work in the UK have a higher risk of getting injured badly enough to be hospitalised, according to a study published yesterday. It led to headlines saying this is 50 per cent more likely for cyclists than non-cyclists. But don’t get off your bike – the research also found that the overall health benefits of cycling vastly outweigh the injury risks. This adds to a lot of evidence suggesting that cycling is extremely worthwhile, but people seem reluctant to start. Of the 230,390 UK commuters that participated in the latest study, only 2.5 per cent said cycling was their main method of commuting. So why are people hesitating? As someone who cycles to work myself, a big worry is the danger of having an accident – and I’m not alone. A 2015 UK government survey found that 64 per cent of people thought riding on roads would be too dangerous. The new study, which looked at outcomes over 10 years, shows those fears aren’t unreasonable – commuting by bike is associated with an increased risk of admission to hospital for injury, with 7 per cent of cyclists experiencing such an injury compared to 4.3 per cent of non-cyclists. Squint a bit, and you can turn that into the “50 per cent more likely” figure mentioned above. But Paul Welsh at the University of Glasgow in the UK, who led the study and who cycles himself, says the risk of death from cycling injury is vanishingly small. In fact, it is far outweighed by the decreased risk of death that comes from the increased physical activity and lower BMI of cyclists. “The data are still very much in favour of cycling for those who are capable of doing so,” says Welsh. Cyclists have a far lower risk of cardiovascular disease, cancer and death compared with people who drive, take public transport or walk to work – a finding supported by this and previous studies. If an extra 1000 people took up cycling for 10 years, we would expect to see 15 fewer cancers, four fewer heart attacks or strokes and three fewer deaths in that group.

3-11-20 Is running or walking better for you? Here’s what the science says
Does pounding the pavement damage your joints? Can you get away with just walking? Sports engineer Steve Haake pits running against walking and dispels some abiding myths. I hated physical education at school. Cross-country was the worst: cold, boring and lung-burning. “Run, don’t walk!” the teacher would shout as we jogged reluctantly through the mud, only to walk as soon as we were out of sight. Over the following four decades, my PE teacher’s angry barks have been echoed in the constant media reports telling me that I should run, whether informing me that jogging could increase my lifespan by years or that training for a marathon would make my heart younger. The benefits of exercise are huge. If it were a drug, it would be a miracle cure. It keeps our hearts strong and blood vessels supple, lessens chronic inflammation and reduces the harmful effects of stress. But do we need to run to get the benefits or can we get a sufficient dose just from walking in the limited time we have for exercise? And what about those who warn about the toll on joints from pounding the pavement? It is common knowledge that running causes arthritis and ruins the knees and hips – but does the evidence back this up? I wanted to find out if my PE teacher’s mantra was right. The idea that running is the best exercise for us – indeed, that it is part of what makes us human – has many champions. Among them is Daniel Lieberman at Harvard University, who maintains that we evolved to run long distances. He thinks that our now largely untapped talent for persistence hunting – chasing animals over long distances – in hot conditions gives us an edge over other animals and shaped our evolutionary history. And we aren’t just good at running because we are good at walking – in fact, technically they are quite different (see “Mechanics of locomotion”). A range of adaptations such as sweat glands and hairless skin to aid cooling, the right balance of muscle types and a special ligament to keep our head stable when running all mean that, over long distances, we can outrun almost any other animal. “Thanks to our evolutionary history, all of us have the anatomy and physiology needed to walk and run – assuming we are not disabled,” says Lieberman. “In today’s world, we have medicalised, commodified and commercialised exercise, but physical activity, at its heart, is something we evolved to do.”

3-11-20 New electrodes can better capture brain waves of people with natural hair
Standard EEG methods can falter when detecting signals from people with coarse, curly hair. Snugged up against the scalp, electrodes can eavesdrop on the brain’s electrical activity. But the signals can weaken when electrodes can’t get close enough to the scalps of people with coarse, curly hair. This design flaw could end up excluding people with this type of hair, including people of African descent, from studies, says engineer Pulkit Grover of Carnegie Mellon University in Pittsburgh. The issue also has clinical implications. Electroencephalograms, or EEGs, which rely on arrays of scalp electrodes to record brain activity, are common clinical tests used to make diagnoses for such diseases as epilepsy. If the electrodes don’t work well, diagnoses could be harder to make. “It’s not intentional. But at the same time, it’s kind of sad,” Grover says. “It’s worth thinking about technology, and about who it has been designed for.” When undergraduate student Arnelle Etienne joined Grover’s laboratory, she combed through the scientific research on EEG technology. “I noticed that a lot of the current solutions wouldn’t work for my hair type,” says Etienne, who is black. EEG technicians try to “MacGyver” their way through, sometimes by asking patients to straighten or steam their hair before the tests, Etienne says. But those workarounds aren’t ideal, especially if EEG measurements are needed quickly. “Some people have been asked to shave parts of their hair to do the test,” Etienne says. “Luckily, that’s not as frequent, but it was shocking to hear.” A team including Grover, Etienne and undergraduate student Tarana Laroia measured how much coarse, curly hair might interfere with measuring brain signals. They found that standard electrodes placed on loose, curly hair created very high impedance, a measurement of resistance to the electrical current. A good EEG signal is considered to have less than 50 kilo-Ohms of impedance; unbraided, curly hair with standard electrodes yielded 615 kilo-Ohms.

3-10-20 Bacteria sacrifice themselves when under attack to save their colonies
Some bacteria self-destruct when their colony is attacked by rivals, but the reason was unclear. Now it seems they sacrifice themselves to save their relatives, just as some insects give their lives to defend their colonies. This kind of sacrifice is rare in nature because it usually contradicts an individual’s evolutionary drive to survive and reproduce. However, many types of bacteria self-destruct when attacked by rival bacteria. To try to understand why this happens, Elisa Granato and Kevin Foster at the University of Oxford developed a way to visualise it. They took a strain of E. coli bacteria that can self-destruct in the presence of a competitor’s toxins and made them turn green when they are preparing to self-destruct and pink when they actually do so. The researchers placed a colony of the modified bacteria in a dish next to a colony of enemy bacteria – a different, unmodified strain of E. coli. Both strains can produce different toxins against closely related colonies. They then watched what happened under a microscope as the colonies battled it out. The modified E. coli on the front line – closest to the enemy bacteria – received a direct hit of the toxins released by their rivals and were killed straight away. Just after, the E. coli just behind the front line, which were exposed to less toxin, switched into self-destruct mode. These bacteria spent an hour building up supplies of their own toxin, before dying off en masse – by bursting open and firing the toxin at the enemy, probably to help the rest of the colony survive. This self-sacrificial counter-attack makes sense from an evolutionary point of view as bacteria often live in colonies of identical clones, says Granato. “It’s like they’re helping their own genes by killing themselves, because they give their clonemates that have the same genes as them a better chance of surviving,” she says.

3-10-20 The science of the adolescent brain
What's going on in there? dolescence is a time of massive change. As children become teenagers, they're subject to growth spurts, voice changes, new body hair, and annoying acne. But perhaps the biggest shifts of adolescence are the invisible ones happening inside the brain. "The brain of an adolescent is no different in size or shape than that of an adult," says board-certified neurosurgeon Marc Arginteanu, M.D., F.A.C.S. "On a standard CAT scan or MRI, your brain and that of your teenager would be indistinguishable. But, in terms of development, your brain is worlds apart from theirs." The teenage brain isn't fully developed, and different parts of the brain mature at different rates. For instance, the prefrontal cortex (PFC), which sits right behind the eyes and is responsible for executive function and rational reasoning, doesn't typically fully mature until age 24, while the amygdala, which is deep in the brain and processes and integrates emotions, emotional behaviors, and motivation, seems to reach full maturity much earlier. Because the relationship between the PFC and the amygdala is off balance in adolescents, they lack the ability to put a cognitive control on emotional processes. This could help explain a common characteristic in teenagers: reckless decision making. In the adult brain, decision making is heavily influenced by the PFC, which helps rationalize. In adolescents, however, decision making is associated with an increase in activity in the striatum, a part of the brain considered to be a primary component of the reward system, and the insula, a part of the brain active during psychological conflicts. "The PFC regulates executive control and our ability to essentially 'put the brakes' on behaviors and step back to reassess," explains Nicole Avena, Ph.D., assistant professor of neuroscience at Icahn School of Medicine at Mount Sinai, New York. "We have an innate tendency to act impulsively and go with our emotional reaction to situations, and the PFC lessens this and allows us to evaluate situations before acting and make better decisions." Since adolescents don't have a fully-developed PFC, it can mean that their mood swings and behaviors can be more aggressive, since they haven't fully gained the ability to control their urges and emotions.

3-10-20 An ancient social safety net in Africa was built on beads
Ostrich eggshell beads suggest the long-distance network was established by 33,000 years ago. Hunter-gatherers strung a social safety net across much of southern Africa starting at least 33,000 years ago, a new study suggests. And it was held together with ostrich eggshell beads. Some of these carefully crafted beads — excavated at two high-altitude rock-shelters in the African nation of Lesotho — were found to have originated more than 100 kilometers away, while others came from more than 300 kilometers away, say anthropological archaeologist Brian Stewart of the University of Michigan in Ann Arbor and his colleagues. Ages of the beads span nearly the last 33,000 years, the scientists report March 9 in the Proceedings of the National Academy of Sciences. Hunter-gatherers inhabiting inland desert or grassland regions probably started a regional exchange network toward the end of the Stone Age, somewhat akin to how many modern hunter-gatherer groups give gifts back and forth to foster cooperation, Stewart says. Ostriches lived in those dry, flat grasslands, but not at the rock-shelter sites. Inland residents could have made the beads from collected ostrich eggshells. The beads were probably then passed from one group of people to another over long distances, Stewart says. The findings indicate that this activity went on for tens of thousands of years longer than anyone previously has demonstrated for a system of cooperation-currying gift exchanges. It’s “highly plausible” that ostrich eggshell beads were transported over long distances in ancient Africa, says archaeologist Nick Barton of the University of Oxford, who was not part of the new study. More work is needed to tell if inland hunter-gatherers perhaps obtained ostrich eggshells near southern Africa’s east coast, where seashells were also collected for bead making during the Stone Age. If so, bead distribution may have started near the east coast, Barton says.

3-10-20 Meet Carlo, an ancient reptile who had part of his face bitten off
A giant marine reptile from the dinosaur era had part of its face bitten off, probably by another member of its species. The huge predator survived the attack, but it lost part of its jaw and developed a severe infection – both of which may have contributed to its ultimate demise. “It’s direct evidence of a violent interaction between members of the same species,” says Dylan Bastiaans at the University of Zurich in Switzerland. The animal was a mosasaur, one of several groups of reptiles that lived in the sea during the dinosaur era. Mosasaurs looked like whales with the heads of crocodiles, and towards the end of the dinosaurs’ reign, they became the top marine predators. Bastiaans and his colleagues studied a mosasaur fossil that was discovered in 2012. The specimen is nicknamed Carlo, after Carlo Brauer, an excavator operator who spotted it in a limestone quarry in the Netherlands. “He actually saved the specimen, or large parts of the specimen,” says Bastiaans. Carlo consists of most of the skull plus a few other bits, so we don’t know if it was male or female. The team has tentatively identified it as Prognathodon sectorius. Prognathodon species were some of the largest mosasaurs, reaching lengths of around 10 metres. They had powerful, crushing jaws and some species are thought to have eaten large sea turtles. “They are one of these super-predators that could potentially feed on almost anything,” says Bastiaans. However, Carlo had major injuries. “We see that it’s missing at least part of the front of its snout,” says Bastiaans. “There must have been some bite there that chopped it off.” The attacker’s teeth left marks: based on their shape and size, the researchers believe they were made by another Prognathodon. Bastiaans says the other mosasaur probably approached from below, as sharks do, and grabbed Carlo’s snout in its jaws.

3-10-20 Repurposed drugs may help scientists fight the new coronavirus
Work on similar viruses is giving researchers clues to develop drugs against the disease. As the new coronavirus makes its way around the world, doctors and researchers are searching for drugs to treat the ill and stop the spread of the disease, which has already killed more than 3,000 people since its introduction in Wuhan, China, in December. The culprit virus is in the same family as the coronaviruses that caused two other outbreaks, severe acute respiratory syndrome and Middle East respiratory syndrome. But the new coronavirus may be more infectious. In early March, the number of confirmed cases of the new disease, called COVID-19, had exceeded 100,000, far surpassing the more than 10,600 combined total cases of SARS and MERS. Health officials are mainly relying on quarantines to try to contain the virus’ spread. Such low-tech public health measures were effective at stopping SARS in 2004, Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, said January 29 in Arlington, Va., at the annual American Society for Microbiology’s Biothreats meeting. But stopping the new virus may require a more aggressive approach. In China alone, about 300 clinical trials are in the works to treat sick patients with standard antiviral therapies, such as interferons, as well as stem cells and traditional Chinese medicines including acupuncture, and blood plasma from people who have already recovered from the virus. Researchers are not stopping there. They also are working to develop drugs to treat infections and vaccines to prevent them (SN: 3/14/20, p. 6). But creating therapies against new diseases often takes years, if not decades. With this new coronavirus, now known as SARS-CoV-2, nobody wants to wait that long. Thanks to their experience developing treatments against the MERS coronavirus, as well as other diseases, such as HIV, hepatitis C, influenza, Ebola and malaria, researchers are moving quickly to see what they can borrow to help patients sooner.

3-9-20 Coronavirus: Risk of death rises with age, diabetes and heart disease
People who have the new coronavirus are most likely to die if they are older or show signs of sepsis or blood clotting problems. That’s according to a study that followed a small group of people infected with the covid-19 virus from diagnosis to hospital discharge or death. Early on in the outbreak, two hospitals in Wuhan, China, were designated to treat people infected with the coronavirus. Until 1 February, people who were diagnosed with the virus in other hospitals in the city were transferred to one of the two for care. By 31 January, 191 adults had been treated for the virus and either discharged or died at the two hospitals. Bin Cao at the China-Japan Friendship Hospital and Capital Medical University in Beijing and his colleagues assessed these cases, looking for patterns in the characteristics of those who survived the virus and those who didn’t. The average age of these individuals was 56, and 62 per cent were men. Around half of those treated had underlying medical conditions, most commonly diabetes and high blood pressure. Of the 191 individuals, 137 were eventually discharged and 54 died. The average time from the onset of the illness to discharge from hospital was 22 days, the team say. Those who didn’t survive the virus died an average of 18.5 days after symptoms began. Death was more likely in people who already had diabetes or coronary heart disease. Older people were more likely to die, as were those showing signs of sepsis or blood clotting problems. Overall, more than half of those hospitalised with the virus developed sepsis. “Poorer outcomes in older people may be due, in part, to the age-related weakening of the immune system and increased inflammation that could promote viral replication and more prolonged responses to inflammation, causing lasting damage to the heart, brain and other organs,” said study co-author Zhibo Liu at Jinyintan Hospital in Wuhan.

3-9-20 Bacteria found leaking from gut to body in people who are obese
Bacterial DNA has been found in the blood, liver and fat of people who are obese, showing that either fragments of bacteria or entire live bacteria are leaking into their bodies from their guts, which shouldn’t be happening. “Even fragments of bacteria can trigger an immune response,” says André Marette at the Québec Heart and Lung Research Institute in Canada. In people who are obese the intestinal barrier is more fragile, Marette says, allowing bacterial fragments or live bacteria to get inside their body. This could contribute to the development of diabetes by causing inflammation in organs such as the liver. We know that obesity increases the risk of type 2 diabetes. To investigate, Marette and his colleagues analysed samples of blood, liver and fat tissue taken from people having surgery for weight loss. The team took many precautions to rule out bacterial contamination, which would have compromised the results. The researchers were surprised to find bacterial DNA in all three types of sample. “I never thought they could actually reach organs,” Marette says. They also found a wide range of bacterial DNA, including some from bacteria known to cause disease, some thought to be beneficial – at least in the gut – and some that live in soil or water rather than in our bodies. “That came as a big surprise to us,” Marette says. The study also found the type of bacteria varied from tissue to tissue and depending on whether people had type 2 diabetes or not. Because the researchers looked only for the presence of bacterial DNA, they can’t say whether the DNA came from living bacteria or from fragments of dead bacteria. Living bacteria can cause potentially fatal infections when they get inside the body, but none of the people tested showed signs of this. Marette plans to try to grow bacteria from such tissue samples in future studies, to see whether they are alive or not.

3-7-20 Recreating Muslim sailors' first voyages to Australia
Indigenous Australians had contact with Indonesian sailors long before the first European settlers arrived in Australia in the 18th Century. The Muslim Makassans traded with the local Yolngu people as early as the 1500s, some experts believe. Now the sea voyage has been recreated, aiming to help young Muslim Australians feel a better sense of belonging.

3-6-20 Slimming down fatty livers in the lab could boost donor organ supply
I am face to face with a freshly removed pig’s liver connected to a maze of tubing and sitting in a clear plastic tub. It isn’t looking healthy – it is dull with a greyish-brown complexion. But then I am given permission to press a button and the equipment whirs into life. The device effectively performs the function of a heart and lungs, and was developed by Peter Friend and his colleagues at the University of Oxford and their spin-out firm OrganOx. It perfuses the liver with oxygenated blood warmed to body temperature, and the organ quickly starts to flush a dark reddy-brown and look glossier, even plumper. These kinds of machines were invented to keep people alive while their heart was stopped for surgery, but smaller versions are now used to keep organs alive outside the body to aid in transplant operations. Such devices are now used in a few heart, liver and kidney transplants, both to extend the time an organ can remain safely out of the body and to help doctors judge if an organ is functioning well. “It’s like taking it for a test drive,” says Constantin Coussios of OrganOx. But the researchers want to go further and start using this ability to keep an organ alive outside the body to manipulate it, and even heal it from disease. Their first goal is to tackle an increasingly common problem, fatty liver disease. This occurs when the organ’s cells accumulate too much fat. Although it can happen in people who are slim, it is more common in those who are overweight, affecting nine out of 10 people who are obese. Depending on the disease’s severity, transplanted fatty livers don’t function as well as transplants of livers in good shape. With waistlines expanding, that means increasing numbers of donated livers have to be turned down. Fatty liver is the explanation for half of all livers rejected for transplant in the UK.2a

3-6-20 A dog in Hong Kong has a low-level infection of the new coronavirus
There’s little reason to believe pet owners should be concerned A pet dog in Hong Kong has a low-level infection with the new coronavirus that the animal may have gotten from its owner, raising concerns that the virus currently spreading around the world can infect pets (SN: 3/4/20). But experts say it’s only a single case so far, and there is currently no evidence that pets can actually get sick from the virus or pass it to people or other animals. “We don’t believe that this is a major driver of transmission,” Maria Van Kerkhove, a technical consultant with the World Health Organization, said in a news conference on March 5. “It’s only one example … and so of course it deserves much more study,” she said. Nasal and oral swabs from the dog, whose owner was infected with the new coronavirus, called SARS-CoV-2 because of its similarity with the 2003 SARS virus, had tested weakly positive, though the animal wasn’t showing any signs of disease, officials in China announced February 28. Officials from China’s Agriculture, Fisheries and Conservation Department isolated the dog in an animal facility in Hong Kong beginning February 26. These initial test results could have been the product of environmental contamination of the dog’s nose and mouth as it sniffed and licked contaminated objects and not signs of an actual infection. But a subsequent test of nasal swabs on March 2, after the dog had been quarantined, was also positive. The dog still has not shown any signs of disease related to COVID-19. Another pet dog from another patient is also in quarantine, but has tested negative for the virus. There’s no current evidence to suggest that dogs can spread the new coronavirus to other dogs or to people, Chinese officials say.

3-6-20 Immune cells in the gut may play a big role in peanut allergies
The finding could lead to new treatments to help curb severe reactions. Severe peanut allergies may stem from the stomach and gut. A surprisingly large pool of cells involved in allergic reactions to peanuts resides in the stomachs and small intestines of allergic adults, scientists report March 5 in Science Immunology. Identifying the gastrointestinal tract as a prime location for allergy molecules is “a huge step forward,” says Cecilia Berin, an immunologist who studies food allergies at the Icahn School of Medicine at Mount Sinai in New York City. Studies on mice hinted that certain immune molecules are made in the gut, but there has been scant evidence of that in people, she says. “This is the first time that we actually see what is happening in the gut” in people with peanut allergies, she says. The new findings may point to treatments for people with food allergies, estimated to affect between 3 and 6 percent of people in the United States. The study focused on an elusive, rare antibody called IgE. Usually present in very small numbers in the body, IgE can sense invaders such as parasites and cause massive immune reactions designed to purge the threat. But in people with allergies, the antibody can go rogue and targets harmless substances, such as peanut proteins. Immunologists Ramona Hoh and Scott Boyd, both of Stanford University School of Medicine, and colleagues studied tissue from the digestive tracts of 19 allergic adults. These people were about to start a clinical trial designed to test the effects of precise doses of peanut protein on their allergies, one of several such trials (SN: 11/18/18). The researchers began by studying RNA in cells from esophagus, stomach and duodenum samples. Cells use this genetic material to make proteins, including specific types of antibodies, such as IgE. Tallying up the various RNA molecules in each sample told the researchers which antibodies were present, and where. The method also let them estimate how many cells were churning these IgE antibodies out.

3-5-20 Coronavirus: Are there two strains and is one more deadly?
Two strains of the new coronavirus are spreading around the world, according to an analysis of 103 cases. But the World Health Organization insists that “there is no evidence that the virus has been changing”. So how many strains are there, and why does it matter? Viruses are always mutating, especially RNA viruses like this one, coronavirus SARS-CoV-2. When a person is infected with the coronavirus, it replicates in their respiratory tract. Every time it does, around half a dozen genetic mutations occur, says Ian Jones at the University of Reading, UK. When Xiaolu Tang at Peking University in Beijing and colleagues studied the viral genome taken from 103 cases, they found common mutations at two locations on the genome. The team identified two types of the virus based on differences in the genome at these two regions: 72 were considered to be the “L-type” and 29 were classed “S-type”. A separate analysis by the team suggests that the L-type was derived from the older S-type. The first strain is likely to have emerged around the time the virus jumped from animals to humans. The second emerged soon after that, says the team. Both are involved in the current global outbreak. The fact that the L-type is more prevalent suggests that it is “more aggressive” than the S-type, the team say. “There do appear to be two different strains,” says Ravinder Kanda at Oxford Brookes University in the UK. “[The L-type] might be more aggressive in transmitting itself, but we have no idea yet how these underlying genetic changes will relate to disease severity,” she says. “I think it’s a fact that there are two strains,” says Erik Volz at Imperial College London. “It’s normal for viruses to undergo evolution when they are transmitted to a new host.” It is vital to know how many strains of the virus exist. Around the world, multiple groups are working on a vaccine for the virus. Any vaccine will need to target features that are found in both strains of the virus in order to be effective.

3-5-20 A more convenient, monthly treatment for HIV cleared a key hurdle
Once-a-month injection of antiretrovirals works just as well as a daily pill regimen, trials show. People living with HIV are one step closer to having a once-a-month treatment alternative to downing two or more pills a day. There is no cure for HIV, the virus that causes AIDS. But combination antiretroviral therapy, or ART, can effectively halt the replication of the virus, nearly eliminating it from the bloodstream and prolonging life expectancy (SN: 11/15/19). For the therapy to work, though, people must stick to a daily regimen of two or more pills, which experts say can be a challenge for many. Now, the results of two phase III clinical trials suggest that a monthly shot of antiretroviral drugs works just as well as daily pills, researchers report March 4 in two studies in the New England Journal of Medicine. If approved by regulators, the therapy could be a more convenient treatment for the estimated 1.1 million people living with HIV in the United States. “From a patient perspective, these results are very positive,” says Elizabeth Tolley, an epidemiologist at FHI 360, a public health nonprofit based in Durham, N.C. Stigma can make people reluctant to keep HIV drugs around the house or to take them each day in front of a loved one, she says. A monthly alternative could be a better option for many. The injectable ART is a long-acting combination of HIV drugs cabotegravir and rilpivirine. One of the phase III clinical trials — the gold standard for getting regulatory approval for a new drug — was led by Chloe Orkin, an HIV researcher at Queen Mary University of London. She enrolled 566 participants who had never tried ART, so they first took the pill version, which included a combination of other HIV drugs, for 20 weeks to get the virus under control. Then, the participants either transitioned to once-a-month shots or continued using pills.

3-5-20 Laser powered liquid jets could inject drugs into skin without needles
A laser that generates a high-speed jet of liquid to push medicines into the skin could one day give people painless, needle-free injections. Pankaj Rohilla and Jeremy Marston at Texas Tech University tested their laser-powered liquid jet on skin-like material and pig skin, with promising results. They say it could be an alternative to conventional injections, provided they can show it works on human skin too. The device focuses a laser beam at a liquid in a glass tube. A small portion of the liquid rapidly heats and vaporises, forming a bubble. This generates enough pressure to force a jet of liquid into the skin at a speed of up to 300 metres per second. The jet is less than a tenth of a millimetre wide, which is designed to minimise the impact of the fast-moving liquid on the skin and prevent pain and bruising. In trials, the liquid jet penetrated 4 millimetres into a skin-like gel – deep enough to deliver drugs under the skin’s surface. When tested on pig skin, the jet reached the tissue just under the skin, where intradermal injections are delivered. “These results were very exciting for us,” says Rohilla. “The next step is to do injections on human cadaver skin.” The new technique would benefit those with a needle phobia, estimated to be as many as one in 10 people, and lower the risk of needle-stick injuries for healthcare workers, says Rohilla. As well as being painful, conventional injections have many limitations that needle-free ones would avoid, says Rohilla. For example, the team’s initial tests suggest the injection would also work with very thick liquids, which will be vital if the technology is used to deliver DNA vaccines – vaccines that use DNA from viruses or bacteria to stimulate the immune system. These are thicker than other types of vaccine and so require more force to inject them into skin with a syringe, he says.

3-5-20 New fossils and artifacts show Homo erectus crafted a diverse toolkit
Some stone tools have a single sharpened edge, while others consist of double-edged designs. Hardly one-tool wonders, ancient hominids called Homo erectus relied on a toolkit that included relatively simple and more complex cutting devices, new discoveries suggest. Excavations at two Ethiopian sites located about 5.7 kilometers apart uncovered partial H. erectus braincases alongside two types of stone tools, paleoanthropologist Sileshi Semaw of the National Research Center on Human Evolution in Burgos, Spain, and colleagues report March 4 in Science Advances. Some artifacts featured a single sharpened edge, while others consisted of double-edged designs such as pear-shaped hand axes. One H. erectus fossil dates to about 1.26 million years ago, the other to between around 1.6 million and 1.5 million years ago. Hominid fossils and stone tools are rarely found together, making the new discoveries particularly noteworthy. East African H. erectus made different types of stone tools over hundreds of thousands of years, apparently selecting implements based on the task at hand or perhaps the quality of rock available, Semaw’s team says. The Ethiopian evidence bolsters previous suggestions, stemming from stone tool finds, that neither H. erectus nor any other hominid made only one kind of stone tool but fashioned a greater variety of relatively simple and more complex implements than has often been assumed (SN: 3/23/15). A large braincase with thick brow ridges, found at the younger Ethiopian site, came from an adult male, the researchers suspect. A small braincase with thin brow ridges, unearthed at the older Ethiopian site, belonged to an adult female, the team suggests. A recent study found that another extinct, distant cousin to modern humans called Paranthropus boisei that lived in East Africa at the same as H. erectus had hands capable of making stone tools (SN: 3/3/20). But such artifacts have yet to be found with P. boisei fossils.

3-5-20 Some dinosaurs might have had fluorescent horns or feathers
As well as being brightly coloured in normal light, some dinosaurs may have had ultraviolet, fluorescing horns, frills or feathers – and a few species might even have used this glow to attract a mate. Fluorescence is relatively common among amphibians and several species of bird have fluorescent features, which absorb ultraviolet light and re-emit it at a different wavelength. Those body parts glow under UV light. Puffins have fluorescent patches on their beaks, for instance, and budgerigars have some fluorescent feathers on their heads. D. Cary Woodruff at the Royal Ontario Museum in Toronto points out that we now know birds are dinosaurs, and that some dinosaurs had feathers while others had horns, frills and spikes that – like a puffin’s beak – were sheathed in keratin. He and his colleagues argue it makes sense that at least some dinosaurs may have enhanced the appearance of these features with fluorescence. One dinosaur that may have done so is Borealopelta, a heavily armoured, 5.5-metre beast that lived 110 million years ago. A remarkable 3D fossil of Borealopelta was discovered in Canada in 2011. The creature has a prominent, 60-centimetre spine jutting out from each shoulder. Even today, the tips of those spines are fluorescent, glowing slightly in UV light. It is possible that this is because fluorescent minerals were incorporated into the spines during the fossilisation process, says Woodruff. But in that case, we might expect the entire spine to fluoresce. The fact that it is only the tips that do so might hint that this reflects some original biological feature, rather like the distinctly coloured, banded beaks possessed by birds like puffins. But even if dinosaurs such as Borealopelta had fluorescent features, they might not have served a biological function. For example, there is no strong evidence as yet that the fluorescent patches on a puffin’s beak enhance its ability to attract a mate.

3-5-20 First self-replicating molecules may have had just two ingredients
The very first life to have existed on Earth may have begun when chemicals started to cooperate. A new study suggests that life is most likely to have formed when at least two kinds of carbon-based chemicals interacted. Sijbren Otto at the University of Groningen in the Netherlands and his colleagues have found that mixtures of simple carbon-based chemicals can spontaneously form elaborate molecules, which can then copy themselves. Such self-replication is a hallmark of life, because it allows organisms to reproduce. Researchers who are trying to figure out how life began have struggled for decades to make self-replicating molecules. There have been some successes, but the resulting molecules have always been carefully designed and rather elaborate. It seemed unlikely that these molecules formed by chance on Earth, even over the course of millions of years. “They don’t emerge very readily,” says Otto. His team combined two kinds of chemicals, both of which are essential to life as we know it. The first were amino acids, the building blocks from which proteins are made. The second were nucleobases, which are crucial components in nucleic acids like DNA and RNA. Both are thought to form naturally. When the team mixed the chemicals together, the amino acids and nucleobases linked together into ring-shaped molecules. Sets of these rings then assembled into cylindrical stacks. The stacks could copy themselves by somehow encouraging other rings to stack together in the same way. The mixture had to be shaken for this to work, but otherwise Otto’s team didn’t have to intervene. The study is one of several in recent years that have offered clues about a new theory of the origin of life. Previous hypotheses often assumed that one crucial chemical arose first and formed a simple kind of life, which later made all the other chemicals and became more elaborate.

3-5-20 Thirdhand smoke wafting off moviegoers hurts air quality in theaters
The pollution is released from tobacco residue on people’s bodies and clothing. “Nonsmoking” doesn’t necessarily mean smoke-free. A new experiment monitoring airborne contaminants inside a nonsmoking theater indicates that hazardous cigarette fumes wafting off moviegoers can degrade air quality. Those pollutants include the carcinogen benzene (SN: 4/26/13) and toxic aldehydes, such as acrolein, formaldehyde and acetaldehyde (SN: 7/27/16). Such thirdhand smoke, released from tobacco residue on people’s skin, hair and clothing, is an important public health concern, researchers report online March 4 in Science Advances. But it’s not yet clear whether the exposure levels seen in this experiment are enough to cause serious health problems, or how much people can protect themselves from thirdhand smoke in public (SN: 11/10/14). The experiment took place in a well-ventilated, nonsmoking theater in Mainz, Germany, which showed four to five films per day. Over four days, the researchers used a mass spectrometer to take a chemical inventory of pollutants exiting the theater’s ceiling vents. These measurements revealed that concentrations of tobacco-related compounds in the theater spiked when new crowds entered — especially for R-rated flicks and late showings, perhaps because audience members were more likely to have been smoking or hanging around smokers before arrival. Previous research has found traces of thirdhand smoke in supposedly nonsmoking areas, but this is the first study to catch people in the act of transferring the pollution. To judge the severity of this pollution, environmental engineer Drew Gentner of Yale University and colleagues compared observed levels of thirdhand smoke components to the amounts of those chemicals that would have been emitted if someone were smoking inside the theater.

3-4-20 The Dream Season 2 review: How the wellness industry ropes people in
The second season of podcast The Dream debunks much of the wellness industry, but creating empathy for the people caught up in it is where the show shines. WELLNESS is a booming industry encompassing everything from fitness and personal care to crystals meant to interact with a person’s “energy field”. Season 2 of podcast The Dream attempts to separate science from pseudoscience by delving into the scams, the regulation of vitamins and supplements, and why people find wellness so compelling. Season 1 took a similar approach in addressing the predatory nature of multi-level marketing schemes. Many of the products and services mentioned in the new season are straightforward enough to debunk. Herbal sex supplements that supposedly mimic Viagra actually have Viagra in them. An intra-vaginal jade egg, purported to balance hormones, led to the lifestyle brand Goop being fined $145,000 for making unsubstantiated claims. And, while taking adaptogens — herbs and other plants that theoretically adapt to the needs of the body — probably won’t do anything to harm you, there isn’t much evidence to show they will help either. As producer Jane Marie narrates with collaborator Dann Gallucci, her cynicism is palpable, even though she has tried out many wellness “treatments” for herself. Each episode explores a different aspect of the industry, including how inaccurate claims persist in part because of a lack of oversight. For example, in the US, although the Food and Drug Administration monitors herbs and supplements, manufacturers don’t need FDA approval before going to market. Marketers also don’t have to explain how supplements can interfere with prescribed medications. At times, the podcast can be a little clunky, such as when Marie says she is going to get ear seeds – seeds that are placed on specific parts of the ear, using similar principles to acupuncture – and Gallucci responds in a very scripted way: “What are ear seeds?”

3-4-20 Smoking bans don't prevent you having to breathe in smoke particles
You can breathe in harmful chemicals from tobacco use even in non-smoking venues because they are carried on smokers’ bodies and clothes. Third-hand smoke – the residue from cigarette fumes that sticks to surfaces and then wafts back into the air – has previously been found indoors in places where smoking is allowed. To find out if third-hand smoke also pollutes non-smoking venues, Drew Gentner at Yale University and his colleagues monitored the air quality in a non-smoking cinema in Germany for four days, after first flushing it with clean air. Smoking is banned inside cinemas and other public places in Germany. They observed spikes of tobacco chemicals in the air just after audiences arrived, which decreased over time but didn’t go away completely. The polluting substances were probably brought in on the bodies and clothes of people who had recently smoked cigarettes or been near smokers, says Gentner. They observed larger spikes during movies rated for those aged 16 and above, most likely because the audiences were older and had greater tobacco exposure than those attending movies suitable for younger people, says Gentner. The amount of tobacco chemicals that people watching the films aimed at older teens and adults were exposed to per hour was equivalent to that inhaled while sitting directly next to someone as they smoke up to 10 cigarettes. The researchers detected a total of 35 tobacco chemicals in the cinema, including known hazards such as benzene, formaldehyde and acrolein. We still don’t know the long-term health impacts of breathing in third-hand smoke, but most public health experts agree that there is no safe level of tobacco smoke exposure, says Gentner. The findings suggest that policies designed to protect non-smokers from second-hand smoke, like banning people from smoking within set distances of buildings, may need to be extended to protect people from third-hand smoke as well, says Gentner.

3-4-20 The secret to killing cancer may lie in its deadly power to evolve
By closely tracking how cancer cells evolve in our bodies, we can identify their hidden weaknesses and find powerful new ways to treat tumours. SHE doesn’t dwell on it, but 82-year-old Lydia Knott knows what will happen to her after death. Her body will be taken to a laboratory for an unusual post-mortem. It won’t be to find the cause of her demise. Knott was diagnosed with lung cancer five years ago. After surgery to remove part of her lung, she is now doing well: “Fine for an 82-year-old, I can’t complain.” But if the disease returns and kills her, Knott wants doctors to learn more about her cancer through a “warm autopsy”, so-called because it happens soon after someone dies. Within 24 hours, a team would remove up to 80 tissue samples and preserve them using liquid nitrogen. One of the aims is to fathom cancer’s surprising ability to evolve. The same forces that shape the tree of life also drive tumours to spawn and spread, generating a vast genetic diversity of cancer cells within a single person. Now, thanks to recent leaps in genetic sequencing, the hope is that we can trace a cancer’s evolutionary journey and create powerful treatments using this information. “We may actually have the technology to cure many cancers – we just haven’t been using the right strategy,” says Robert Gatenby at the Moffitt Cancer Center in Tampa, Florida. We might even be able to stop tumours developing in the first place, but it won’t be easy. “We are battling natural selection, one of the fundamental laws of the universe,” says Charles Swanton at the Francis Crick Institute in London, co-leader of the study that Knott has signed up to. “But I think this is our best shot.” We have known since the 1970s that tumours arise when a mutation occurs in one of the genes within a cell that control its reproduction. Our cells are continually replicating themselves – even in healthy tissues – by growing and splitting in two, to replenish those that have worn out.

3-4-20 Coronavirus' economic threat just got real
The Fed's shocking move shows policymakers are taking the threat very seriously. n Monday morning, the economic threat from the coronavirus got real for U.S. policymakers. In a surprise announcement, the Federal Reserve said it would immediately cut its interest rate target by half a percentage point, bringing the new target to a range of 1-to-1.25 percent. Normally, the central bank announces its interest rate changes at its regularly scheduled meetings, the next of which happens March 17 and 18. And when the Fed has made cuts in recent years, it's limited itself to one-fourth of a percentage point reductions at a time. This will be the first time the Fed has cut interest rates this much in one go, or done so outside its normal schedule, since the financial crisis of 2008. It was also a unanimous decision among the voting Fed officials. "We saw a risk to the outlook of the economy and we chose to act," Fed Chair Jerome Powell told reporters, in a press conference attempting to project measure and calm, even as the unusual nature of the decision underscored the potential seriousness of the situation. The good news is that the Fed's move remains a preemptive measure to an economic threat that may materialize, rather than an after-the-fact response. The COVID-19 coronavirus has infected around 90,000 people worldwide — mostly in China, but with outbreaks rapidly expanding in Italy, Iran, Japan, South Korea, and other countries, leading to widespread shutdowns of social and economic activity in those places. Thus far, the United States has remained relatively unaffected, with our biggest problem being disrupted supply chains — specific companies and sectors here unable to get parts and inputs from abroad — and export-dependent industries facing a slowdown in global demand. But with domestic consumer spending making up 70 percent of our economic output, America has an enormous cushion to fall back on. The Fed's move is insurance, designed to make it even less likely that things go south. In terms of fiscal policy responses from Congress, nothing concrete has happened yet. But discussions have definitely sped up. On Monday, Massachusetts Senator Elizabeth Warren — one of the contenders for the Democrats' presidential nomination — proposed a $400 billion spending package to shore up the economy against the coronavirus. It includes emergency paid sick leave for people who contract the virus, as well as their close relatives; boosts to unemployment insurance; federal aid to shore up state and local budgets; emergency aid to hospitals and local providers to cover the potential costs of treating people with COVID-19; public investments to build out our response to the virus; and more. President Trump, meanwhile, took to Twitter to call for a one-year reduction in the payroll tax, and his administration is reportedly considering its own plan to reimburse hospitals for the costs of caring for COVID-19 patients, through established emergency measures designed to respond to natural disasters.

3-4-20 How badly prepared is the world for a coronavirus pandemic?
LAST week, the World Health Organization raised its assessment of the global risk from the novel coronavirus to Very High – its maximum level. The virus has escaped containment in at least four countries. But the WHO is eager for nations to keep practising containment measures (see “Why the WHO won’t use the p-word”). These can slow the spread of the virus in countries that only have a few cases. But as long as it is circulating somewhere in the world, new cases will continue to crop up in countries even if they have effective containment practices. Mike Ryan of the WHO said on 28 February that the goal isn’t to stop the virus spreading, but “to slow its spread so health systems can prepare”. But what will that take? Can countries around the world handle a pandemic? The short answer is no. “Health systems, north and south, are just not ready,” Ryan said emphatically. When the epidemic started in the city of Wuhan, in China’s Hubei province, a rapid build-up of severe cases overwhelmed medical staff. There wasn’t enough medical protective gear and there were insufficient intensive care beds – along with oxygen and ventilators needed to help people with severe pneumonia breathe – to meet the high demand. It also strained the delivery of ordinary medical care. Bruce Aylward of the WHO, who led an international mission to study China’s response, noted last week that containment stopped the virus spreading generally and overwhelming healthcare in every Chinese province but Hubei, and mitigation measures aimed at preventing contact between people are driving case numbers down in Hubei. But this isn’t permanent: China is still building hospitals, growing public health capacity and buying more ventilators for when cases rise again, he said. Countries whose health systems struggle during a bad winter flu season, or which can’t build new hospitals in days or lock down whole cities, could struggle to repeat China’s success in slowing an outbreak.

3-4-20 We were warned – so why couldn’t we prevent the coronavirus outbreak?
THE world dodged a bullet in 2003 when a global effort contained the SARS coronavirus, after it jumped from bats to humans in China and then spread to 26 countries. We nearly had another close call when MERS, another bat coronavirus, spilled over into people in 2012. A year later, Chinese scientists found SARS-like viruses in fruit bats that could infect human cells And in 2016, the World Health Organization put coronaviruses among the top eight known viral threats requiring more research. So you would think we would have some coronavirus drugs and vaccines by now. But there are none licensed. That is why we are hurriedly testing drugs designed for other viruses to see if they can help, and running expedited trials for experimental vaccines. Why were we so unprepared for a threat we knew about? After 2003, there was a burst of research, but it was short-lived. “From 2005, it became really difficult to get funding for work on SARS coronavirus,” says Rolf Hilgenfeld at the University of Lübeck, Germany. This was partly because, when SARS disappeared, there was no obvious market waiting for drugs or vaccines to treat it, says David Heymann at the London School of Hygiene and Tropical Medicine. Only big drug companies have the money and expertise to get drugs or vaccines through human trials, and without a market they can’t invest. But Hilgenfeld says agencies that fund research also lost interest, because “prominent virologists believed that SARS coronavirus was a one-time only thing”. Compared with other coronaviruses, SARS had an extensive genetic mutation that prompted some virologists to guess that this was what allowed it to suddenly spread in humans – and that such a mutation was unlikely to happen again. They were right about the second part. The covid-19 virus doesn’t have this mutation, but it spreads even better in humans than SARS did.

3-4-20 As the coronavirus outbreak evolves, we answer some key questions
In this rapidly changing public health emergency, many unknowns remain. As a new coronavirus that has infected tens of thousands around the world continues to spread, scientists and public health officials are racing to understand the virus and stop the growing public health crisis. In this rapidly evolving situation, many unknowns remain. Here’s what we know so far about the new virus — called severe acute respiratory syndrome coronavirus 2, or SARS-CoV-2 — and the disease that it causes. We will update these answers as more information becomes available. The virus is a novel type of coronavirus, a family of viruses that typically cause colds. But three members of this viral family have caused deadly outbreaks. Severe acute respiratory syndrome coronavirus, or SARS-CoV, Middle East respiratory syndrome coronavirus, or MERS-CoV, and now SARS-CoV-2 all cause more severe disease, including pneumonia. SARS-CoV-2 got its name because it is similar to SARS-CoV. There are still a lot of unknowns, like how contagious the virus is. And SARS-CoV-2 is a new coronavirus and hadn’t infected people before the outbreak in China, so no one has prior immunity to it. That means everyone is susceptible to getting infected and transmitting the virus to others. Most cases have been mild. Of people who contract the virus, 3.4 percent die, according to the World Health Organization. Officials say the number will probably change as the outbreak continues, and varies from place to place. The analysis of about 44,000 cases of COVID-19 from China shows that the elderly are most vulnerable. Older people, especially those with heart disease and other conditions, are more likely to die. Middle-aged and elderly adults are most likely to contract the virus, while children and teenagers seem to rarely get infected or become seriously ill when they do catch the virus (SN: 2/14/20). Even though their symptoms are mild, infected children may still spread the virus. People with COVID-19 often have a dry cough and sometimes shortness of breath. And the vast majority of patients with this illness have fever, according to reports characterizing patients from China.

3-4-20 Human brains have ‘time cells’ that let us recall when events happened
For the first time, we have found “time cells” in the human brain. These help us remember the sequence and timing of events, and they could be targets for treating memory loss caused by Alzheimer’s disease. “You’ll remember that you saw Jennifer Aniston yesterday and not a few weeks ago because there’ll be a cell that fired yesterday that didn’t fire on any other day,” says Daniel Bush at University College London, who wasn’t involved in the discovery. “That’s a time cell.” These cells were first identified in rats based on their unique pattern of activity during the creation of episodic memories that help recall specific events. But they hadn’t been identified in humans until now. Bradley Lega at the University of Texas Southwestern Medical Center and his colleagues found the signs of time cells in the brains of 27 people who were undergoing a procedure to remove part of their brain as treatment for their epilepsy. For ethical reasons, it is difficult to study individual neurons in the brains of living people, says Steven Poulter at Durham University, UK. Recording from pre-surgical epileptic patients offers rare insight, he says. Tiny electrodes inserted into the participants’ brains allowed Lega’s team to measure electrical activity from individual neurons in their hippocampus while the people completed a memory test. The test required participants to view a series of 12 to 15 words, which each appeared on a screen for 1.6 seconds, and then later recall as many of the words as they could. Lega’s team found that the more consistently the time cells fired during memorisation, the more likely the participants were to remember the correct words. More consistent time cell activity across the task also increased the likelihood that the participants would recall the words more closely to the order in which they were presented. This is similar to the findings in rats.

3-3-20 Silver uses a surprising trick to stop the spread of bacteria
Silver seems to help prevent harmful bacteria from spreading by disrupting how they move around. The precious metal has long been used to stop the transmission of bacteria – for example, in the filters of some medical face masks and in the antibacterial coatings used on the International Space Station. But until now, one reason it has a sanitising effect had gone unnoticed. To find out, researchers at the University of Arkansas exposed E. coli to small doses of positively charged silver ions, which are toxic to bacteria. They then used a powerful microscope to watch what happened to the bacteria’s flagella – the whip-like motors that bacteria use to move around. Exposing the bacteria to silver ions stalled their flagella, causing the cells to “become much, much slower”, says Yong Wang, one of the researchers on the team. These bacteria also changed direction more, so they spent less time moving in a line than non-exposed bacteria. Silver has been used for decades to stain flagella to make them easier to see under the microscope, says Jim Thomas at the University of Sheffield in the UK. But this is probably the first time its effect on flagella has been studied, he says. David Coil at the University of California, Davis, says silver won’t always have this effect because not all bacteria have flagella. But silver stops microbes in other ways too – for instance, in higher doses, it can damage cell walls and cause bacteria to explode. Stopping bacteria from moving as easily makes it harder for them to escape and therefore become resistant to silver’s effects, says Thomas. “Treatments that work through multiple pathways or targets are much more difficult for bacteria,” he says.

3-3-20 Freeze-dried jellyfish could help us grow new human skin
Stinging upside-down jellyfish may not be something you want to touch, but they could be used to make scaffolds for healing skin. “We found that an abundant jellyfish species, Cassiopea andromeda, in the Gulf of Mexico is similar in structure to human skin,” says Nayeli Rodríguez-Fuentes at the Scientific Research Center of Yucatán in Mexico, who led the work. Natural and synthetic tissue scaffolds are used to repair skin, often after surgery or to heal burns. These allow new skin cells to be attached from the surgery patient or from a donor, so the more porous and similar to human skin that the scaffold material is, the better the cells are accepted and grow to regenerate tissue. Collagen, the most abundant protein in mammals and the component responsible for skin’s stretchiness, is the standard choice for natural scaffold biomaterials. It is usually extracted from pigs and cows, but sources from the ocean, including jellyfish and octopuses, have been tested before. Rodríguez-Fuentes’s team collected more than 100 upside-down jellyfish in waters off the north coast of the Yucatán peninsula and separated the non-stinging bell structures – usually the top side of more typical jellyfish species – from the animals’ bodies. These jellyfish quickly bloom in their hundreds in warm waters, and are invasive in some areas. They could also be farmed, says Rodríguez-Fuentes, making them an attractive resource for healing skin without upsetting ecosystems. Instead of extracting collagen from the jellyfish to make scaffolds, the researchers wanted to use the jellyfish tissue structure itself. To do this, they removed cells by freeze-drying the jellyfish bells in a salt solution and then bleached them with hydrogen peroxide. They were then dehydrated using alcohol, producing decellularised, sponge-like collagen structures.

3-3-20 How to help your child avoid unnecessary medical care
If your child has ever put up a fight when you try to give them medicine, you may have wondered if that antibiotic was really, absolutely necessary. You'd be right to wonder: Many children receive "low-value services" — defined as "health-care interventions that are more expensive and equally or less effective than an alternative, including doing nothing," according to the authors of a recent study in Pediatrics. Researchers listed and analyzed how frequently doctors prescribed 20 low-value pediatric services, including imaging procedures for sinus infections, and oral antibiotics for colds. They discovered that one in nine publicly insured and one in 11 privately insured children received such unneeded health-care services in 2014. It's important to note that the services named in the study aren't low-value for all pediatric patients; indeed, these services are high-value for specific groups of children with specific health issues. But the problem is that these services are being used more widely than they should, and in many cases, they're unnecessary and costly. Low-value services are common for several reasons, says study lead author Kao-Ping Chua, MD, Ph.D., a pediatrician, researcher, and assistant professor of pediatrics at the Susan B. Meister Child Health Evaluation and Research Center at the University of Michigan Medical School. "In some cases, the doctor may not be aware that a service is low-value," he points out. "In other cases, it's a social issue: Parents understandably want their child's suffering to be alleviated, and doctors understandably want to help," Dr. Chua continues. "Sometimes doctors will feel like parents will be dissatisfied if they recommend observation, prompting them to order an intervention." But it's important to note that parents aren't the sole drivers of unnecessary medical care: Certain low-value services are common among adults, too.

3-3-20 Brain waves common during sleep also show up in awake sheep
If humans have similar ‘wake’ spindles, they may play a daytime role in holding onto memories. Here’s something neat about sleeping sheep: Their brains have fast zags of neural activity, similar to those found in sleeping people. Here’s something even neater: These bursts zip inside awake sheep’s brains, too. These spindles haven’t been spotted in healthy, awake people’s brains. But the sheep findings, published March 2 in eNeuro, raise that possibility. The purpose of sleep spindles, which look like jagged bursts of electrical activity on an electroencephalogram, isn’t settled. One idea is that these bursts help lock new memories into the brain during sleep. Daytime ripples, if they exist in people, might be doing something similar during periods of wakefulness, the researchers speculate. Jenny Morton, a neurobiologist at the University of Cambridge, and her colleagues studied six female merino sheep with implanted electrodes that spanned their brains. The team collected electrical patterns that emerged over two nights and a day. As the sheep slept, sleep spindles raced across their brains. These spindles are akin to those in people during non-REM sleep, which accounts for the bulk of an adult’s sleeping night (SN: 8/10/10). But the electrodes also caught spindles during the day, when the sheep were clearly awake. These “wake” spindles “looked different from those we saw at night,” Morton says, with different densities, for instance. Overall, these spindles were also less abundant and more localized, captured at single, unpredictable spots in the sheep’s brains. As to the job of these daytime bursts, “I have no idea,” Morton says. But the results hint that these spindles may somehow help the brain handle certain kinds of information during the day, not just at night.

3-3-20 The ancient hominid species that includes ‘Nutcracker Man’ may have made tools
Newly described fossils are the first hand, arm and shoulder specimens from the same Paranthropus boisei individual. Paranthropus boisei, an African hominid that lived between around 2.3 million and 1.2 million years ago, may have strong-armed its way into stone-tool making with a deft touch. That’s the implication of the first hand, arm and shoulder fossils discovered from the same P. boisei individual, say paleobiologist David Green and colleagues. The fossils suggest that this extinct species combined powerful arms suited to tree climbing with grasping hands capable of fashioning stone implements, the researchers report in the April Journal of Human Evolution. P. boisei, a distant cousin to modern humans, lacked a thick, powerfully gripping thumb characteristic of its hominid contemporary, Homo erectus (SN: 3/24/15), a prolific maker of sophisticated stone tools. But the newly described hand bones suggest that P. boisei gripped well-enough to make and use simple stone and bone tools, just as other members of the human evolutionary family may have as early as 3.3 million years ago (SN: 5/20/15). That’s long before the emergence of the Homo genus, which appeared around 2.8 million years ago. But reports of tool-making before Homo originated are controversial. “This is the first evidence that creatures that were almost certainly not our direct ancestors could have made tools,” says paleoanthropologist Bernard Wood of George Washington University in Washington, D.C. “So we can no longer assume — nor should we ever have assumed — that only Homo could make tools,” says Wood, who was not involved with the new research. It’s tempting to argue that only H. erectus, which had a brain approaching twice the average size of P. boisei’s, could have made teardrop-shaped, double-edged hand axes that date to around the same time as the two hominids. Those tools demanded more skill and planning than earlier, simpler cutting implements. But the case is not closed, says Green, of Campbell University School of Osteopathic Medicine in Buies Creek, N.C. “We’ll need to find tools that can be confidently associated with P. boisei and assess its technical abilities before assuming that H. erectus was the superior toolmaker.”

3-1-20 Meet the compulsive robot who could help us treat OCD better
A robot that mimics the behaviours of people who have obsessive-compulsive disorder (OCD) could help us understand what drives the condition and even improve how we treat it. OCD involves obsessive worrying that compels people to carry out rituals like repeated hand washing. People who have it experience anxiety if they can’t complete these compulsions. Researchers are using the robot to recreate this compulsive drive to complete an action. The research is at an early stage, but the team gave New Scientist a sneak preview. As I am someone who has lived with OCD for a long time, the researchers wanted to see what I made of their robot. The tiny robot is programmed to try to achieve three goals: “eat”, “groom” and avoid damage caused by bumping into things. The robot can only groom by colliding with a solid post, which inflicts damage. The grooming is intended to mimic a behaviour that can be harmful if repeated excessively. Just like in our brains, the robot’s core drives can conflict with each other. The robot eats by touching light patches on the floor of a roughly square-metre-sized enclosure, replenishing its energy. But the damage caused by grooming runs down the robot’s energy supply. When these motivations are balanced and the robot is set free to roam, it runs out of energy, and so fails, 10 per cent of the time. To recreate a compulsive behaviour, the researchers tweaked the robot’s drive to groom by setting the desired grooming level beyond what the robot can achieve. Under these conditions the robot fails 95 per cent of the time. Current treatment for OCD involves exposing someone to the things that trigger their obsessive thoughts and resulting compulsive behaviours and then preventing them from responding. If the robot can be made to adapt to changes in its environment that mimic exposure to triggers, this could point to future ways to improve treatment, the researchers say.


125 Evolution News Articles
for March 2020

Evolution News Articles for February 2020