2-22-19 How the zebra got its stripes: The problem with 'just-so' stories
When it comes to explaining why zebras have stripes, it’s best to remember that some issues are not black and white. Biologists have been debating the puzzle since Darwin’s time, but a study published on Wednesday offers further evidence for one of the most promising explanations: that the stripes deter biting flies. In the parts of Africa where zebras live, there are blood-sucking horseflies that carry lethal diseases such as trypanosomiasis. Clearly, zebras would do well to avoid being bitten. The idea is that the stripes somehow confuse the flies so that they don’t land on the zebras. A team led by Tim Caro of the University of California, Davis tracked captive zebras and horses at a site in England. Horseflies circled round both, but they landed on horses significantly more often. Putting striped coats on the horses’ bodies meant the horseflies landed there less often – but still landed on their heads, which were uncovered. The implication is that the stripes were having a real effect. The hypothesis backed by a lot of evidence, but does that mean it’s the only reason for a zebra’s stripes? Not necessarily. Some ideas don’t seem to stand up, notably the suggestion that the stripes help zebras cool down on hot days – if that were true, we would expect a lot more tropical animals to be stripy. But other ideas seem to have more to them. One which at first seems ridiculous is that the stripes are a form of camouflage. Obviously, zebras are not inconspicuous. But the stripes could create “dazzle camouflage”: overwhelming the predator’s visual system and making it hard to track the zebra’s movement. Think about the experience of watching a herd of zebras all dashing in different directions, and imagine trying to pick out one of them to bring down.
2-22-19 African hominid fossils show ancient steps toward a two-legged stride
New cache of Ardipithecus ramidus bones reveals advances in upright walking 4 million years ago. Fossils unearthed from an Ethiopian site not far from where the famous hominid Ardi’s partial skeleton was found suggest that her species was evolving different ways of walking upright more than 4 million years ago. Scientists have established that Ardi herself could walk upright (SN Online: 4/2/18). But the new fossils demonstrate that other members of Ardipithecus ramidus developed a slightly more efficient upright gait than Ardi’s, paleoanthropologist Scott Simpson and colleagues report in the April Journal of Human Evolution. The fossils, excavated in Ethiopia’s Gona Project area, are the first from the hominid species since 110 Ar. ramidus fossils, including Ardi’s remains, were found about 100 kilometers to the south (SN: 10/24/09, p. 9). Gona field surveys and excavations from 1999 through 2013 yielded Ar. ramidus remains, including 42 lower-body fossils, two jaw fragments and a large number of isolated teeth. Several leg and foot bones, along with a pelvic fragment, a lower back bone and possibly some rib fragments, came from the same individual. The same sediment layers, characterized by previously dated reversals of Earth’s magnetic field, contained fossils of extinct pigs, monkeys and other animals known to have lived more than 4 million years ago. Unlike Ardi, the fossil individual at Gona walked on an ankle that better supported its legs and trunk, says Simpson, of Case Western Reserve University in Cleveland. And only the Gona hominid could push off its big toe while striding on two legs.
2-21-19 A ban on artificial trans fats in NYC restaurants appears to be working
The fatty acids have been linked to heart disease. New Yorkers fond of eating out in the last decade weren’t just saved from doing the dishes. Residents’ blood levels of artificial trans fats, which increase the risk heart disease, dropped following a 2006 citywide policy that banned restaurants from using the fats. Researchers analyzed blood samples of adult city residents from before and after the ban, taken as part of a health and nutrition survey that queried participants on their dining habits. The samples, 212 from 2004 and 247 from 2013–2014, revealed a drop from 49.2 to 21.3 micromoles per liter, suggesting that trans fat levels plunged by about 57 percent overall among New Yorkers. For people who dined out frequently, the decrease was even greater: Levels of the fats declined by about 62 percent for New Yorkers who ate out four or more times per week, the team reports online February 21 in the American Journal of Public Health. An estimated 1 in 5 city residents eats out that frequently, says study coauthor Sonia Angell, deputy commissioner of the New York City Department of Health and Mental Hygiene in Queens. “We think [the ban] has just been a win overall for New Yorkers … in particular for those who dine out more frequently.” Artificial trans fats, also called trans fatty acids, end up in foods like fried chicken and doughnuts, anything that is fried, baked or cooked in partially hydrogenated vegetable oils. The fats increase the amount of low-density lipoprotein, commonly known as “bad” cholesterol, in the body while lowering high-density lipoprotein, the “good” cholesterol.
2-21-19 Dinosaur extinction lines up closely with timing of volcanic eruptions
Were the dinosaurs seen off by an asteroid, or a flurry of volcanic eruptions? Two new studies on the timing of volcanic events help us piece together the story of Earth’s most famous mass extinction, but they leave it unclear exactly what triggered the demise of so many species. Around three-quarters of the species on Earth are thought to have perished in the Cretaceous-Palaeogene extinction event 66 million years ago, most famously including all dinosaurs except the ancestors of modern birds. In the geological records, the event coincides with a layer of rock with high levels of iridium – evidence of an asteroid impact. Most geologists think this impact created a huge crater at Chicxulub, Mexico. The impact could have caused a global soot cloud that blocked out the sun. However, the extinction also coincided with a burst of intense volcanic activity that formed a huge rock formation known as the Deccan Traps in western India. Similar volcanic events have been implicated in other mass extinctions in Earth’s history. Eruptions can warm the climate by releasing massive quantities of greenhouse gases or cause cooling by putting sun-blocking aerosols into the high atmosphere. To get a more precise idea about the timing of the Deccan eruptions, Courtney Sprain of the University of California, Berkeley, and colleagues used argon-argon dating to estimate the age of the lava flows. Another team, led by Blair Schoene of Princeton University, New Jersey, used a different method, uranium-lead dating. Both studies agree that the Deccan eruptions took place over a period lasting around a million years, beginning around 400,000 years before the extinction event. But on precise details, their conclusions differ. Schoene and his colleagues suggest the Deccan eruptions occurred in four bursts. The second was the most rapid and it began tens of thousands of years before the asteroid impact.
2-21-19 Why kids may be at risk from vinyl floors and fire-resistant couches
Chemicals called semivolatile organic compounds have been linked to health problems. Home decor like furniture and flooring may not be notorious polluters like gas-guzzlers, but these indoor consumer products can also be significant sources of potentially dangerous chemicals. Kids who live in homes with all vinyl flooring or living room couches that contain flame retardants have much higher concentrations of chemicals called semivolatile organic compounds in their blood and urine than other children. Researchers reported those results February 17 at the annual meeting of the American Association for the Advancement of Science. Manufacturers commonly use semivolatile organic compounds, such as plasticizers and flame retardants, to make electronics, furniture and other household trappings (SN: 11/14/15, p. 10). “Many of these chemicals have been implicated in adverse health outcomes in children — things like ADHD, autism … even cancer,” environmental health researcher Heather Stapleton of Duke University said in a news conference. “It’s important that we understand the primary sources of these chemicals in the home.” Stapleton and her colleagues investigated the in home exposure to semivolatile organic compounds of 203 children ages 3 to 6. The team collected dust and air samples, along with small pieces of items like couch cushions, from the kids’ homes. The researchers also gathered urine and blood samples from the children. Children living in homes with all vinyl flooring had concentrations of a by-product of the plasticizer benzyl butyl phthalate in their urine of about 240 nanograms per milliliter on average. Meanwhile, kids living in homes with no vinyl flooring had only about 12 nanograms per milliliter on average. Children with the highest exposure showed 20 to 40 percent of the “reference dose” for benzyl butyl phthalate — that is, the highest daily dose that the U.S. Environmental Protection Agency considers safe to ingest without negative consequences over a person’s lifetime.
2-21-19 A deer-sized T. rex ancestor shows how fast tyrannosaurs became giants
The newly discovered fossil’s name, Moros intrepidus, means ‘the harbinger of doom’. A new dinosaur shows that even Tyrannosaurus rex had humble beginnings. Dubbed Moros intrepidus, or “the harbinger of doom,” the new species is one of the smallest tyrannosaurs yet discovered from the Cretaceous Period. Analyses of the animal’s fossilized leg show that the creature would have stood only 1.2 meters at the hip, and weighed an estimated 78 kilograms — about the size of a mule deer, researchers report February 21 in Communications Biology. Dating to around 96 million years ago, the fossil is the oldest tyrannosaur found in North America. Its discovery helps fill in a 70-million-year gap in the evolution of tyrannosaurs leading up to the ferocious giants like T. rex. Teeth from early, petite tyrannosaurs have been found in rocks in North America dating to the Late Jurassic Period around 150 million years ago, when larger predator dinosaurs called allosaurs topped the food chain. But the next time tyrannosaurs are seen in the North American fossil record is 70 million years later, when they’ve become the colossal top predators. When, and how, the dinosaurs sized up within that period is a mystery. Paleontologist Lindsay Zanno of North Carolina State University in Raleigh and her colleagues dug for 10 years around Emery County in Utah, searching for clues to solve that mystery. That’s where the team discovered M. intrepidus’ long, thin leg, a characteristic indicative of a swift runner, quite unlike later titanic tyrannosaurs. “What Moros shows is that the ancestral stock of the big tyrannosaurs was small and fast,” says Thomas Carr, a vertebrate paleontologist at Carthage College in Kenosha, Wis., who wasn’t involved in the study. And it “suggests that the tyrannosaurs became giant some time in that 16-million-year stretch between Moros and the earliest of the big guys.”
2-21-19 Teeny T. rex relative discovered in US
A newly discovered relative of Tyrannosaurus rex stood just over a metre tall at the hip, a study shows. The diminutive tyrannosaur reveals crucial new information about how T. rex established itself as a dominant carnivore in North America. Early in their evolution, tyrannosaurs were small, but at some stage, the hulking T. rex along with others emerged as apex predators. The new fossil helps fill a 70-million-year gap in the fossil record. Discovered in Emery County, Utah, the animal lived about 96 million years ago, during the later part of the Cretaceous Period. Tyrannosaurs, or "tyrant lizards" - the group to which this specimen and T. rex belong - ruled the predatory roost on land during the last 15 million years before the Chicxulub asteroid slammed into the Yucatan Peninsula 66 million years ago. T. rex could reach more than 3.5m tall as measured at the hip. But, as co-author Lindsay Zanno, from North Carolina State University, explained, it wasn't always this way: "Early in their evolution, tyrannosaurs hunted in the shadows of archaic lineages such as allosaurs that were already established at the top of the food chain," she said. Our understanding of the evolutionary events leading up to the appearance of giant tyrannosaurs has been limited by the lack of complete fossils in North America. Small-ish, primitive tyrannosaurs have been found in North America dating from the Jurassic Period (around 150 million years ago). By around 81 million years ago, North American tyrannosaurs had become enormous beasts. But the fossil record in between these two time periods is patchy. The lower leg bones of the new species, Moros intrepidus, were discovered in the same area where Dr Zanno and her team had previously found Siats meekerorum, a giant meat-eating dinosaur belonging to a group known as the carcharodontosaurs. This larger predator lived during the same period as Moros. The researchers estimate that Moros intrepidus was about the size of a modern mule deer, weighing about 78kg. It was seven years old when it died and was almost fully grown.
2-20-19 Footballers really are working harder and getting injured more often
English Premier League footballers will enjoy a mid-season break next winter, partly in an attempt to reduce injuries. Some say footballers have never had it so easy, but a study of player injuries confirms the modern game is increasingly taking its toll. Ashley Jones at Leeds Beckett University in the UK and his colleagues tracked 243 players from 10 clubs across four of the divisions below the English Premier League in the 2015/16 season. They found players had an average of 1.9 injuries per player per season, compared to 1.3 in the 1997/98 and 1998/99 seasons combined – the last time a similar study was conducted. “It’s a different game now,” says Jones. “Twenty years ago you had footballers trying to be athletes. Now we have athletes who can play football.” Today’s players run around 30 per cent further than in 2006, but recovery time has not increased. Lower league teams play a 46-game season, with additional cup competition matches. It is no surprise that old injuries flare up more often, says Jones. Of the injuries the group tracked, 17 per cent were reoccurrences of an existing problem, up from 7 per cent in 1997-9. And 40 per cent of modern injuries were the result of repetitive stress and strain placed on players’ bodies over time. Some things haven’t changed. The most common injury remains a hamstring strain. And problems tend to peak twice in the year: during winter and in the first few weeks of the season. Coaches could be pushing players too hard and too early, says Jones. “It’s not needed. These players don’t lose fitness in the summer like they used to.”
2-20-19 Why a data scientist warns against always trusting AI’s scientific discoveries
Data-mining algorithms aren’t good at communicating uncertainty in results, Genevera Allen says. We live in a golden age of scientific data, with larger stockpiles of genetic information, medical images and astronomical observations than ever before. Artificial intelligence can pore over these troves to uncover potential new scientific discoveries much quicker than people ever could. But we should not blindly trust AI’s scientific insights, argues data scientist Genevera Allen, until these computer programs can better gauge how certain they are in their own results. AI systems that use machine learning — programs that learn what to do by studying data rather than following explicit instructions — can be entrusted with some decisions, says Allen, of Rice University in Houston. Namely, AI is reliable for making decisions in areas where humans can easily check their work, like counting craters on the moon or predicting earthquake aftershocks (SN: 12/22/18, p. 25). But more exploratory algorithms that poke around large datasets to identify previously unknown patterns or relationships between various features “are very hard to verify,” Allen said February 15 at a news conference at the annual meeting of the American Association for the Advancement of Science. Deferring judgment to such autonomous, data-probing systems may lead to faulty conclusions, she warned. Take precision medicine, where researchers often aim to find groups of patients that are genetically similar to help tailor treatments. AI programs that sift through genetic data have successfully identified patient groups for some diseases, like breast cancer. But it hasn’t worked as well for many other conditions, like colorectal cancer. Algorithms examining different datasets have clustered together different, conflicting patient classifications. That leaves scientists to wonder which, if any, AI to trust.
2-20-19 A 30 minute walk may reduce blood pressure by as much as medication
Just 30 minutes of exercise every morning may be as effective as medication at lowering blood pressure for the rest of the day. A study found that a short burst of treadmill walking each morning had long-lasting effects, and there were further benefits from additional short walks later in the day. In experiments, 35 women and 32 men aged 55 to 80 followed three different daily plans, in a random order, with at least six days between each one. The first plan consisted of uninterrupted sitting for eight hours, while the second consisted of one hour of sitting before 30 minutes of walking on a treadmill at moderate intensity, followed by 6.5 hours of sitting down. The final plan was one hour of sitting before 30 minutes of treadmill walking, followed by 6.5 hours of sitting which was interrupted every 30 minutes with three minutes of walking at a light intensity. The study was conducted in a laboratory to standardise the results, and men and women ate the same meals the evening before the study and during the day. Michael Wheeler at the University of Western Australia in Perth and colleagues found that blood pressure was lower in men and women who took part in the exercise plans, compared with when they did not exercise. The effect was especially seen with systolic blood pressure, which measures pressure in blood vessels when the heart beats and is a stronger predictor of heart problems such as heart attacks than diastolic blood pressure, which measures the pressure in blood vessels when the heart rests between beats. Women also saw extra benefits if they added in the short three-minute walks throughout the day, although the effect was less for men. The team say they do not know why there was a gender difference, but think it may due to varying adrenaline responses to exercise and the fact that all women in the study were post-menopausal and therefore at higher risk of cardiovascular disease.
2-20-19 How to upgrade your thinking and avoid traps that make you look stupid
Even the most intelligent people can make ridiculous mistakes – but there are simple things all of us can do to act more wisely and avoid blinkered thinking. PAUL FRAMPTON was looking for love. A 68-year-old divorcee, he was delighted to strike up a friendship on an online dating site with someone claiming to be the Czech glamour model Denise Milani. They soon arranged to meet during one of her modelling assignments in South America. When he arrived in La Paz, Bolivia, however, he was disappointed to find that Milani had been asked to fly to another shoot. But could he pick up the suitcase she had left? He did, and was subsequently arrested and charged with smuggling 2 kilograms of cocaine. It may seem like an obvious honey trap, yet Frampton wasn’t exactly lacking in brainpower. An acclaimed physicist, he had written papers on string theory and quantum field theory. How could someone so clever have been so stupid? Recent psychological research shows that Frampton’s behaviour isn’t as exceptional as it first appears. IQ does correlate with many important outcomes in life, including academic success and job performance in many workplaces. But it is less useful at predicting “wise” decision-making and critical thinking, including the capacity to assess risk and uncertainty and weigh up conflicting evidence. Indeed, as I discuss in my new book The Intelligence Trap, intelligence and expertise can sometimes make you more likely to err. This has important consequences, leading not only to errors like Frampton’s, but also to the political polarisation we see on burning issues such as Brexit or climate change. Here are some of the big intellectual traps that lead smart people to act stupidly. Luckily there are science-backed ways to avoid them.
2-20-19 We don't know what a fifth of our genes do - and won’t find out soon
We still have no idea what 20 per cent of protein-coding genes are for. What’s more, we’ve stopped making progress, according to a study looking at what we know about yeast and human proteins. “Basically we really don’t have a clue,” says team leader Valerie Wood of the University of Cambridge in the UK. Her team started by defining what is known or unknown. For instance, we might be able to tell that a protein is an enzyme from its sequence, but if we don’t know what reaction it catalyses its function cannot be said to be known. Wood compares it to taking a car to pieces – recognising that one piece is, say, a wire is not much help understanding what it’s for. When the team applied these criteria to yeast proteins, they found that the function of most of them was discovered in the 1990s. Progress slowed in the 2000s and plateaued in the 2010s with the function of a fifth still unknown. Next the team showed that the same proportion of human protein-coding genes remain a mystery. “There are 3000 human proteins whose function is unknown,” says Wood. The team did not look at the rate of progress for human proteins, but Wood thinks the situation is similar. There are two reasons why progress is grinding to a halt, she says. Firstly, a common way to find out what protein-coding genes do is to mutate them in animals such as mice and zebrafish to see what happens. The mystery proteins don’t show up in these screens, perhaps because they are involved in processes such as ageing whose effects are subtle. Secondly, funders are turning down applications to study these unknown proteins because of the risk of people spending years working on them without any results.
2-19-19 Ancient humans thrived in rainforests by hunting monkeys and squirrels
Dangerous animals, diseases and poor resources: three features of rainforests that have led many to believe that these environments were generally too inhospitable for ancient humans to live in or move through. New evidence for sophisticated monkey hunting dating back 45,000 years has shown that not only could our species live there, but it thrived as well. An international team of scientists analysed around 15,000 bone and tooth fragments from the Fa-Hien Lena Cave in Sri Lanka, thought to be the oldest archaeological site occupied by humans in the country. They found that these humans were able to survive by hunting small, quick, tree-dwelling animals, such as monkeys and giant squirrels. They did so almost continuously until around 4000 years ago. “We’re just now starting to see how flexible early humans were in terms of their behaviour,” says Michelle Langley of Griffith University, Brisbane, a bone and tooth tool analyst on the investigation. This hunting was sophisticated and sustainable, Langley says. “They were going for the biggest, healthiest monkeys,” she says. “The ones that have the most meat on them. “We’re fairly sure they’re not using traps or snares, because if you use these traps you don’t get to choose what exact animal gets caught in it.” Langley and her colleagues are still trying to determine how precisely the early hunters did it, but remains at the site include tiny bone points, which could have been used in bows and arrows, darts or as the tips of spears. These weren’t simply fragments of bone, they had been carefully shaped and styled to fit the purpose. One macaque canine tooth showed signs of having being shaped and then used as a cutting and stabbing tool.
2-19-19 Neolithic skull found by Thames 'mudlarkers'
Here's a piece of history pulled from the muddy banks of the River Thames. It's a skull fragment that is 5,600 years old. It dates to a time long before there was any permanent settlement on the site we now know as London. Investigations indicate it belonged to a male over the age of 18. There are older Neolithic remains that have been recovered in the region, but what makes this specimen especially interesting is that it's the earliest ever skull found by "mudlarkers". If you haven't heard of them before - they're the band of mostly amateur archaeologists who scour the Thames' edges at low tide for objects of intrigue and antiquity. And they're constantly picking up fascinating items - many of which end up in the Museum of London, where this frontal bone will now be displayed from Wednesday. "Mudlarkers are hugely knowledgable," she told BBC News. "They understand where finds will emerge and what's of archaeological interest. And it's really great that they work with us so we can share what they discover, because very often they will turn up things that are very different to what we find elsewhere in the city. Mudlarking requires a permit from the Port of London Authority, and if human remains are identified, the police have to be informed. “Upon reports of a human skull fragment having been found along the Thames foreshore, detectives from South West CID attended the scene," explained DC Matt Morse at the Metropolitan Police. "Not knowing how old this fragment was, a full and thorough investigation took place, including further, detailed searches of the foreshore. The investigation culminated in the radiocarbon dating of the skull fragment, which revealed it to be likely belonging to the Neolithic Era." It's hard to imagine what London looked like before London. But the region was probably covered in extensive woodland, said Dr Redfern. The man, when he was alive, was very likely "a farmer rather than a hunter-gatherer", she added. "From the Neolithic onwards, there’s evidence for farmsteads, but no evidence for a large permanent settlement until after the Claudian conquest." Roman Emperor Claudius' troops invaded Britain in AD 43.
2-18-19 PTSD may one day be treated with a common blood pressure drug
A WIDELY used blood pressure medicine could help people overcome post-traumatic stress disorder (PTSD). The drug seems to make it easier for people to learn to stop being afraid of a past experience. It successfully helped people in a lab test lose a mild fear they had just developed. People can experience PTSD after a frightening event, such as an assault or car crash. It can be debilitating, and involves nightmares and flashbacks. Antidepressants and therapy that lets people remember what happened while in safe surroundings can both help, but neither works perfectly. A few years ago, researchers noticed that people who have experienced trauma tend to have fewer PTSD symptoms if they happen to be taking blood pressure medicines that block a hormone called angiotensin. This hormone is thought to bind to receptor proteins in parts of the brain involved in learning. When a drug that blocks angiotensin, called losartan, was tested in mice, the animals lost fears learned in the lab, such as a fear of sounds linked to receiving an electric shock, more quickly. Now Benjamin Becker at the University of Electronic Science and Technology of China in Chengdu and his colleagues have carried out a similar test in people. They trained 59 men to develop a mild fear by giving them a small electric shock whenever they were shown an image of a coloured square. Electrodes on the participants’ skin showed that they soon began sweating whenever they saw the square – a sign of fear or alertness. The volunteers were then given either losartan or a placebo tablet. After 90 minutes, they were shown the square again, this time without shocks, so they would unlearn their fear reaction. The men who received losartan were faster to stop sweating in response to the square than those given the placebo.
2-18-19 Brain cells combine place and taste to make food maps
These double-duty neurons, discovered in rats’ hippocampi, may help animals find food Sometimes a really good meal can make an evening unforgettable. A new study of rats, published online February 18 in the Journal of Neuroscience, may help explain why. A select group of nerve cells in rats’ brains holds information about both flavors and places, becoming active when the right taste hits the tongue when the rat is in a certain location. These double-duty cells could help animals overlay food locations onto their mental maps. Researchers implanted electrodes into the hippocampus, an area of the brain that is heavily involved in both memory formation and mapping. The rats then wandered around an enclosure, allowing researchers to identify “place cells” that become active only when the rat wandered into a certain spot. At the same time, researchers occasionally delivered one of four flavors (sweet, salty, bitter and plain water) via an implanted tube directly onto the wandering rats’ tongues. Some of the active place cells also responded to one or more flavors, but only when the rat was in the right spot within its enclosure. When the rat moved away from a place cell’s preferred spot, that cell no longer responded to the flavor, the researchers found. A mental map of the best spots for tasting something good would come in handy for an animal that needs to find its next meal.
2-18-19 This optical illusion breaks your brain for 15 milliseconds
Move your head towards these rings of dashed lines and the circles will appear to turn clockwise. Pull your head away and the motion reverses. This is the Pinna-Brelstaff illusion – and it has just been explained. It seems to be due to a communication delay between the regions of your brain that process vision. “It’s kind of like if you’re at a party where you’re listening to a voice amongst lots of noise,” says Ian Max Andolina at the Chinese Academy of Sciences in Shanghai. “The physical motion is like background noise and the illusion is the voice in the noise you have to pick out. It takes a little longer to do that.” Andolina and his colleagues trained two macaques to indicate whether they saw any rotation in images that were actually in motion. Then they showed them the Pinna-Brelstaff illusion, and found that the macaques perceive illusory motion similarly to nine human observers. Macaques were used because they have a very similar vision processing system to humans. The macaques in this experiment had electrodes in their brains, allowing the researchers to see exactly how they processed the optical illusion. The team found a 15-millisecond delay between the activity of neurons that perceive global motion – in this case the illusion that the entire set of lines is moving – and those that perceive local motion, in this case that there is actually no movement. Our brains probably have the same delay, which may seem like a flaw, says Andolina, but they are just being efficient. When we see something, our brain tries to quickly guess what it is. Normally, that guess is pretty accurate because the physical rules of our environment are usually consistent. Here, your brain is using a shortcut, substituting apparent motion for actual motion.
2-18-19 Stone Age Europe may have been home to no more than 1500 people
Stone Age Europe was a lonely place to live. An assessment of ancient population sizes suggests a vast swathe of western and central Europe may have been home to no more than 1500 people at any one time. Our species, Homo sapiens, arrived in Europe about 43,000 years ago. Archaeological evidence, particularly the appearance of distinctive stone tools at multiple sites, suggests these humans rapidly spread across the continent. But it’s an open question exactly how many people lived in Europe at this time. Now Isabell Schmidt and Andreas Zimmermann at the University of Cologne, Germany, have estimated the average population size in a period of European prehistory called the Aurignacian, between 42,000 and 33,000 years ago. The two researchers looked at a large chunk of Europe stretching from northern Spain in the west to Poland in the east. They plotted the location of the approximately 400 known Aurignacian sites across this area. This revealed that humans really occupied just 13 small regions of the continent – leaving most areas effectively uninhabited. To estimate how many hunter-gatherer groups lived in these 13 regions, Schmidt and Zimmermann looked more closely at the archaeological evidence, including how far stone material was likely transported to make tools at these sites. They argue that from the way the sites cluster, the 13 regions were home to no more than about 35 different hunter-gatherer groups. To get a sense for how many people lived in those 35 groups, the researchers used information about more recent hunter-gatherers recorded by explorers as they spread throughout the world in the past few centuries. Groups that most closely resembled the Aurignacians in terms of the animals they hunted contained about 42 individuals, on average.
2-17-19 The sixth mass extinction
The populations of the world’s wild animals have fallen by more than 50 percent, and humanity is to blame. (Webmaster's comment: If it takes us 100-200 years to kill off 75% or more of all species THAT IS A MASS EXTINCTION. 100-200 years was only a blink of the eye in previous extinctions! Mass extinction events do not happen overnight. It might take 100's of years for the full effect of an asteroid strike or a massive volcanic eruption to play out. So will human devastation of most animal life.)
- What’s gone wrong? As the human population has swelled to 7.5 billion, our species’ massive footprint on planet Earth has had a devastating impact on mammals, birds, reptiles, insects, and marine life. We’ve driven thousands of species to the edge of extinction through habitat loss, overhunting and overfishing, the introduction of invasive species into new ecosystems, toxic pollution, and climate change.
- How many species are already extinct? Scientists can only guess. Earth is home to between 9 million and as many as 1 trillion species—and only a fraction have been discovered. Vertebrate species have, however, been closely studied, and at least 338 have gone extinct, with the number rising to 617 when one includes those species “extinct in the wild” and “possibly extinct.”
- How many species are endangered? There are 26,500 species threatened with extinction, according to the International Union for Conservation of Nature (IUCN), a global network of some 16,000 scientists. That includes 40 percent of amphibian species, 33 percent of reef-building corals, 25 percent of mammals, and 14 percent of birds. There are now only 7,000 cheetahs left, and the number of African lions is down 43 percent since 1993.
- Is a mass extinction underway? Possibly. Many scientists now believe humans are living through a “mass extinction,” or an epoch during which at least 75 percent of all species vanish from the planet. The previous five mass extinctions occurred over the past 450 million years; the last one occurred about 66 million years ago, when the aftermath of a massive asteroid strike wiped out the dinosaurs.
- How fast is this happening? Extremely fast. Species extinction is an ordinary part of the natural processes of our planet; in fact, 99 percent of all species that ever lived on Earth are gone. It’s the pace of recent extinctions that is alarming. More than half of the vertebrate extinctions since 1500 have occurred since 1900.
- What are the consequences? Potentially enormous. The loss of species can have catastrophic effects on the food chain on which humanity depends. Ocean reefs, which sustain more than 25 percent of marine life, have declined by 50 percent already—and could be lost altogether by 2050. Insects pollinate crops humans eat.
- Can extinct species be resurrected? Using DNA technology, scientists are working on re-creating species that have disappeared. The technology, called “de-extinction,” is likely at least a decade off, although there are a few possible ways to go about it.
2-17-19 Tooth plaque shows drinking milk goes back 3,000 years in Mongolia
Milk proteins preserved in tartar show that ancient Mongolians drank cow, yak and sheep milk. Ancient people living in what’s now Mongolia drank milk from cows, yaks and sheep — even though, as adults, they couldn’t digest lactose. That finding comes from the humblest of sources: ancient dental plaque. Modern Mongolians are big on dairy, milking seven different animal species, including cows, yaks and camels. But how far into the past that dairying tradition extends is difficult to glean from the usual archaeological evidence: Nomadic lifestyles mean no kitchen trash heaps preserving ancient pots with lingering traces of milk fats. So molecular anthropologist Christina Warinner and her colleagues turned to the skeletons found in 22 burial mounds belonging to the Deer Stone culture, a people who lived in Mongolia’s eastern steppes around about 1300 B.C. The hardened dental plaque, or tartar, on the teeth of the skeletons contained traces of milk proteins, Warinner, of the Max Planck Institute for the Science of Human History in Jena, Germany, said February 16 at the annual meeting of the American Association for the Advancement of Science. Those proteins showed that the people drank milk from cows, yaks, goats and sheep, but not from camels or reindeer, which modern day Mongolians milk today. Ancient Mongolians’ DNA also revealed that they weren’t able to digest lactose as adults. Instead, the Deer Stone people, like modern Mongolians, may have relied on bacteria within the gut, known as the gut microbiome, to break down the lactose, Warinner said.
2-17-19 Your phone and shoes are home to completely unknown life forms
Anyone hoping to discover a new species may only need to look as far as the soles of their shoes or the phone in their pocket. A study of 3500 swab samples taken from people’s shoes and phones has found nine unstudied branches of bacterial life. The samples were taken by Jonathan Eisen, of the University of California, Davis, and his team from members of the public attending sporting events, museums, and educational events in the US. When they sequenced and analysed the DNA of the bacteria in each sample, they found that 35 different phyla of bacteria were present. Phyla are large branches of the family tree of life, and are subdivisions of the larger kingdoms, which include bacteria, plants or animals. According to official nomenclature lists, there are only 39 phyla of prokaryotic organisms – those that have small, bacteria-type cells that lack a true nucleus. But the team found nine possible additional phyla living on shoes and phones, suggesting that there is a vast variety of bacterial life that we know almost nothing about. “We have only scratched the surface of understanding microbial diversity, even right in front of us,” says Eisen. The team found that 10 per cent of the samples they took contained DNA from bacteria belonging to such so-called microbial dark matter – organisms that we know little about because they are difficult to grow and study in the lab. The samples also contained bacteria belonging to extremely rare groups, such as Edwardsbactera, first discovered in an underground water aquifer, and Diapherotrites, which was previously found in water seeping underground in an abandoned goldmine.
2-16-19 Why some Georgia O’Keeffe paintings have ‘art acne’
A new imaging technique could help art curators track destructive bumps over time. Like pubescent children, the oil paintings of Georgia O’Keeffe have been breaking out with “acne” as they age, and now scientists know why. Tiny blisters, which can cause paint to crack and flake off like dry skin, were first spotted forming on the artist’s paintings years ago. O’Keeffe, a key figure in the development of American modern art, herself had noticed these knobs, which at first were dismissed as sand grains kicked up from the artist’s New Mexico desert home and lodged in the oil paint. Now researchers have identified the true culprit: metal soaps that result from chemical reactions in the paint. The team has also developed a 3-D image capturing computer program, described February 17 at the annual meeting of the American Association for the Advancement of Science, to help art conservators detect and track these growing “ailments” using only a cell phone or tablet. O’Keeffe’s works aren’t the first to develop such blisters. Metal soaps, which look a bit like white, microscopic insect eggs, form beneath the surfaces of around 70 percent of all oil paintings, including works by Rembrandt, Francisco de Goya and Vincent van Gogh. “It’s not an unusual phenomenon,” says Marc Walton, a materials scientist at Northwestern University in Evanston, Ill. Scientists in the late 1990s determined that these soaps form when oil paint’s negatively charged fats, which hold the paint’s colored pigments together, react with positively charged metal ions, such as zinc and lead, in the paint. This reaction creates liquid crystals that slowly aggregate beneath a painting’s surface, causing paint layers on the surface to gradually bulge, tear and eventually flake off.
2-15-19 Vaping can help smokers quit—at a cost
A major new study has found that e-cigarettes can help smokers quit—good news, because smoking causes nearly 6 million deaths a year, including 480,000 in the U.S. The bad news, reports NPR.com, is that many people who use e-cigarettes to stop smoking end up hooked on vaping, which carries its own health risks. For the study, British researchers recruited 886 smokers who wanted to quit and split them into two groups. The first received nicotine gum, inhalers, and other standard replacement treatments; the second were given e-cigarettes. Both groups also received a month of weekly one-on-one counseling sessions. After a year, 18 percent of the e-cigarette group had quit, compared with 10 percent of those using traditional therapies. “Anything that helps smokers avoid heart disease and cancer and lung disease is a good thing,” said lead researcher Peter Hajek, from Queen Mary University of London, “and e-cigarettes can do that.” However, 80 percent of the quitters in the e-cigarette group were still vaping at the one-year mark; only 9 percent of the quitters in the traditional nicotine replacement group were still using those products. Continued e-cigarette use worries some scientists because of growing evidence of vaping’s harmful health effects. A U.S. study unveiled last week found that compared with nonusers, people who vape have a higher risk of stroke (by 71 percent), heart attack (59 percent), and heart disease (40 percent).
2-15-19 Kids using too much toothpaste
Parents are putting an unhealthy amount of toothpaste on their kids’ brushes, the Centers for Disease Control and Prevention has warned. The CDC and the American Dental Association advise that children ages 3 to 6 use no more than a pea-size amount of fluoride paste, to prevent the youngsters from swallowing large amounts while brushing. While fluoride helps prevent cavities—which is why it’s added to toothpaste and tap water—it can also damage and discolor children’s teeth when consumed in excess. But in a CDC study of more than 5,000 kids ages 3 to 15, only 49 percent of the 3-to-6 cohort brushed with the recommended pea-size dollop of paste, and more than 38 percent coated either half or all of the brush. Jonathan Shenkin, a spokesman for the ADA, tells The New York Times that parents should keep buying fluoride toothpaste, “but use it in the proper quantity so your children don’t swallow too much.” The study also found that nearly 80 percent of kids started brushing later than recommended; the CDC says they should begin the moment their first tooth comes through.
2-15-19 Breakfast and weight loss
“Eat breakfast like a king, lunch like a prince, and dinner like a pauper,” goes the old adage. Yet new research suggests the first meal of the day isn’t as important as many believe—throwing into question the widely held belief that eating breakfast promotes weight loss by “jump-starting the metabolism.” Australian researchers analyzed 13 previous studies relating to breakfast, weight, and calorie intake in the U.S. and other high-income countries. They found that those who ate breakfast actually consumed 260 more calories on average than those who didn’t, reports Vox.com, and were nearly a pound heavier. They saw no significant difference in metabolic rates between breakfast eaters and abstainers. The analysis has its flaws: The trials examined ran for a maximum of only 16 weeks, and mostly didn’t factor in the types of food eaten by participants. The authors also acknowledge that breakfast is beneficial for children. But for adults, they conclude, there’s “no evidence to support the notion that breakfast consumption promotes weight loss.”
2-15-19 A dialect quiz shows we still cling to our regional identities
What do you call your grandmother? Do the words but and put rhyme? Would you eat a bread roll, a bap, a bun or a cob? If you grew up in the UK or Ireland, an online quiz by The New York Times will try to pinpoint where by collecting your answers to 25 questions like these. For a small sample of New Scientist journalists, the quiz proved shockingly accurate. “There are a lot of distinct dialects in the UK for a small land mass,” says Laurel MacKenzie, a linguist at New York University. Dialects develop when groups are isolated from one another, which has been the case for most of the thousands of years in which people have lived in the UK and Ireland. Although it is now very easy to travel, dialects stick around because they are a matter of local pride and identity. “People hold on to their traditional ways of speaking because that’s who they are,” says MacKenzie. Her favourite dialect words are “barm” – a bread roll in Manchester – and “mither”, which means bother in north-west England. These differences aren’t just reflected in society. By studying how people speak using ultrasound, researchers have learned that people move their tongues in different ways, even when they are making the same sound. “There’s so much variation in language and so much of it is under the surface,” says MacKenzie. One important factor that isn’t taken into account by the New York Times quiz is class. Regardless of where you are, people higher on the social class ladder tend to sound the same, but lower down the ladder, you hear a lot more regional variation. That’s also true of other countries.
2-15-19 STEM professors’ beliefs on intelligence may widen the racial achievement gap
Racial minorities can suffer lower grades if their teachers see intelligence as fixed. Beliefs among some university professors that intelligence is fixed, rather than capable of growth, contribute to a racial achievement gap in STEM courses, a new study suggests. Those professors may subtly communicate stereotypes about blacks, Hispanics and Native Americans allegedly being less intelligent than Asians and whites, say psychologist Elizabeth Canning of Indiana University in Bloomington and her colleagues. In turn, black, Hispanic and Native American undergraduates may respond by becoming less academically motivated and more anxious about their studies, leading to lower grades. Even small dips in STEM grades — especially for students near pass/fail cutoffs — can accumulate across the 15 or more science, technology, engineering and math classes needed to become a physician or an engineer, Canning says. That could jeopardize access to financial aid and acceptance to graduate programs. “Our work suggests that academic benefits could accrue over time if all students, and particularly underrepresented minority students, took STEM classes with faculty who endorse a growth mind-set,” Canning says. Underrepresented minority students’ reactions to professors with fixed or flexible beliefs about intelligence have yet to be studied. But over a two-year period, the disparity in grade point averages separating Asian and white STEM students from black, Hispanic and Native American peers was nearly twice as large in courses taught by professors who regarded intelligence as set in stone, versus malleable, Canning’s team reports online February 15 in Science Advances.
2-15-19 Meet the man who made CRISPR monkey clones to study depression
Hung-Chun Chang hopes his work will lead to new treatments for depression and schizophrenia. One year after the birth of the world’s first two cloned primates, a team in China has used CRISPR gene editing and cloning to create monkeys that show some symptoms of depression and schizophrenia. While some researchers have praised the work’s potential for helping us understand psychiatric disorders in humans, others have raised ethical concerns. Lead scientist Hung-Chun Chang, of the Institute of Neuroscience in Shanghai, told New Scientist about how he hopes the monkeys will help us better understand mental health and find new treatments. (Webmaster's comment: Note that the cutting-edge research is being done in CHINA!)
- How did you create these monkeys? We are working on the BMAL1 gene, which affects how our body responds to the day-night cycle.
- What symptoms do these monkeys have? The most direct result is that they are not getting enough sleep.
- How can you know that these aren’t just symptoms of sleep deprivation? It’s impossible to separate the effects of sleep deprivation on monkey’s mental state from their genetic mutation.
- What are you hoping to learn from this work? We will use these monkeys for drug testing
- Couldn’t this research be done in mice or people? Monkeys have an identical body clock to humans.
- Is it ethical to genetically engineer monkeys to be depressed? Gene editing in cynomolgus monkeys, the species we used here, is permitted worldwide.
- What else is your team is working on? We are trying to create an Alzheimer’s model.
2-14-19 A gut bacteria toxin that damages DNA may be involved in bowel cancer
Gut bacteria could be to blame for bowel cancer. People with the condition often have higher levels of certain strains of Escherichia coli in their digestive systems. Now, a toxin produced by the bacteria has been shown to damage DNA in gut cells – possibly the first step towards turning cancerous. While some strains of E. coli can cause food poisoning, others are more friendly and form part of the bacterial community in a healthy gut. Previous studies have found about 20 per cent of E. coli strains produce a DNA-damaging toxin called colibactin. People with inflammatory bowel disease and bowel cancers often have elevated levels of these strains in their digestive systems. Aiming to find out what colibactin does to our body, Emily Balskus at Harvard University in Massachusetts and her colleagues injected colibactin-producing E. coli into human gut cells. They found the toxin severely damaged the cells’ DNA after 16 minutes. Cells injected with non-colibactin-producing E. coli didn’t experience such changes. When the team repeated the experiment in mice, they found the same result in their colon cells. “It’s the first time we see evidence that colibactin directly damages DNA in cells and mice,” says Balskus. They’ve yet to investigate if this damage will turn cancerous, “but in other settings, such as tobacco products, there is good evidence that [DNA destruction] is carcinogenic,” says Balskus. It’s not known when or why some E. coli produce colibactin. Many people have E. coli capable of producing colibactin in their gut, but appear to be completely healthy. “We don’t know what that means,” says Balskus.
2-14-19 Chemicals 'repair damaged neurons in mice'
New results suggest ageing brains can potentially be rejuvenated, at least in mice, according to researchers. Very early-stage experiments indicate that drugs can be developed to stop or even reverse mental decline. The results were presented at the 2019 meeting of the American Association for the Advancement of Science. The US and Canadian researchers took two new approaches to trying to prevent the loss of memory and cognitive decline that can come with old age. One team, from the University of California, Berkeley, showed MRI scans which indicated that mental decline may be caused by molecules leaking into the brain. Blood vessels in the brain are different from those in other parts of the body. They protect the organ by allowing only nutrients, oxygen and some drugs to flow through into the brain, but block larger, potentially damaging molecules. This is known as the blood-brain barrier. The scans revealed that this barrier becomes increasingly leaky as we get older. For example, 30-40% of people in their 40s have some disruption to their blood-brain barrier, compared with 60% of 60-year-olds. The scans also showed that the brain was inflamed in the leaky areas. Prof Daniela Kaufer, who leads the Berkeley group, said that young mice altered to have leaky blood-brain barriers showed many signs of aging. She discovered a chemical that stops the damage to the barrier from causing inflammation to the brain. Prof Kaufer told BBC News that not only did the chemical stop the genetically altered young mice from showing signs of aging, it reversed the signs of aging in older mice. "When you think of brain aging you think about the degeneration of cells and losing what we have," she said. "What these results show is that you are not losing anything. The cells are still there and they just needed to be 'unmasked' by reducing the inflammation."
2-14-19 CRISPR could help us protect ourselves from viruses like flu and HIV
CRISPR gene editing could let us hack the immune system to give lasting protection against HIV and other infections. Experiments in mice suggest that the technique could be used to give people immunity from a range of viruses for which there are no effective vaccines. Justin Taylor, at the Fred Hutchinson Cancer Research Center in Seattle, Washington, and colleagues used the CRISPR technique on B cells. These white blood cells are part of our natural immune system and secrete antibody proteins that attack particular bacteria and viruses. While effective against many diseases, these protective antibodies don’t work as well as needed against some viruses. This is one of the reasons researchers have struggled to develop vaccines against some of the most lethal infections. To get around this problem, better versions of some antibodies can be created artificially and then given to patients. For example, palivizumab can be made in the lab and is very effective against the respiratory syncytial virus (RSV), which infects the respiratory tract and is a serious threat to infants and older people. Injections of palivizumab are used to treat RSV infections in these high-risk groups, but the antibody breaks down quickly, meaning these expensive injections have to be repeated every month. Taylor and his colleagues hope that editing the DNA of B cells to produce better antibodies and then injecting them back into the body could lead to a steady supply of new antibodies, without the need for repeat injections. If it works, this could provide immunity against certain pathogens. The team tested their idea by giving B cells from mice the genetic instructions to make palivizumab for themselves. They found that a single injection of these cells protected 15 mice from the virus for up to 82 days.
2-14-19 Can teenagers get vaccinated without their parents’ permission?
Measles outbreaks are spreading in two neighbouring US states, Washington and Oregon, with the former declaring a public health emergency. These states are among 17 that have laws allowing parents to opt out of vaccinating their children on the basis of personal beliefs. The latest outbreak has seen teenagers turning to social media to ask how they can get vaccinated against their parents’ wishes. Legally, it is a difficult question, because children can’t necessarily make their own medical decisions. Regulations vary from state to state, but in general, some minors can access certain treatments without parental consent. Vaccines are not always specified on this list, but in some states the law is vague enough that a minor could potentially have a legal right to a vaccination. In Oregon, anyone 15 or older can get hospital care, dental and vision services, and immunisations without parental permission. In Washington, minors can receive immunisations without their parents’ consent if their doctor determines they are a “mature minor”, which takes into account their age, ability to understand the treatment and self-sufficiency, although they need not be legally independent to qualify. Other states allow even younger children to access some vaccines. In California, 12-year-olds can consent to medical treatment for sexually transmitted infections (STIs). These include the vaccine for human papillomavirus (HPV), which has become a target for anti-vaccination campaigners. “There were lots of claims about things that are bad about the HPV vaccine, which really aren’t founded in any scientific evidence. That created a lot of mistrust among parents,” says Claudia Borzutzky, a physician in the adolescent medicine clinic at Children’s Hospital Los Angeles. Californian minors can also consent to the hepatitis B vaccine. “We don’t have the same resistance to hepatitis B as we do with other vaccines, which is mysterious to me because all our vaccines have the same efficacy. People forget it’s an STI,” says Borzutzky. Almost every state allows minors to consent to medical care related to reproductive health – birth control, pregnancy testing, abortion – and drug and alcohol abuse services. Some states also let minors access mental-health services and sexual-assault treatment without a parent’s permission.
2-14-19 Find tonic water bitter? Part of your brain may be on the small side
Here comes a taste test with a surprising outcome. A study involving 1600 people found the volume of a particular brain region is reversely linked to how bitter people find tonic water. Before anyone thought to mix it with gin, tonic water was developed as a treatment for malaria. It contains a medicinal substance called quinine, which gives tonic water its bitterness. Previous studies have found that individuals perceive the strength of bitter flavours like quinine differently depending on their genes. Daniel Hwang at the University of Queensland in Australia and his colleagues wondered if brain size also plays a role. They collected brain scans of 1600 volunteers, who were also asked to rate the bitterness of a quinine solution. The team found that the size of a brain region – the left entorhinal cortex in the temporal lobe – is associated with how intensely someone perceives bitterness. Those who found the drink less bitter tended to have a bigger left entorhinal cortex. The entorhinal cortex has previously been linked to our sense of smell, but it is unclear how its volume is associated with taste perception. “There are various possibilities – a smaller volume may result in a shorter time for the taste signal to transfer across the brain,” says Hwang. It is still unclear whether the volume of certain brain regions affects our perception of other food and drinks. “This is the first study relating volumetric differences and taste, and our findings warrant future research on not only bitter, but also sweet and even salty, sour and umami taste responses,” says Hwang. Those who find tonic water to be extremely bitter shouldn’t assume that they have a smaller left entorhinal cortex, though. Hwang says genetics probably also plays a role in determining our taste sensation.
2-14-19 Offspring from older sperm are fitter and age more slowly
Sperm with stamina sire the healthiest, longest-lived offspring, at least in zebrafish. The finding challenges the prevailing orthodoxy about what determines the physical traits of sperm, which could have important evolutionary implications. It also suggests that the methods fertility clinics use to select sperm – which instead favour the sprinters – could be improved. “I definitely do think this is relevant,” says team leader Simone Immler at the University of East Anglia in the UK. “We miss out on a lot of steps during artificial fertilisation technologies.” Half of zebrafish sperm stop swimming just 25 seconds after entering water, although some fare better and survive for about 1 minute. To see if there was any difference between these short and relatively longer-lived sperm, Immler’s team split zebrafish ejaculate into two parts. One part was mixed with both eggs and water. With the other part, the eggs were added 25 seconds after the water, meaning that only the longer-lived sperm had a chance of fertilising them. The results were striking. The offspring sired by longer-lived sperm were fitter, says Immler. “They not only reproduced more throughout life, they also lived longer.” However, the effects were less pronounced in female offspring than male ones. Allowing only longer-surviving sperm to fertilise eggs might act as a form of quality control, weeding out sperm with harmful mutations, says Immler. But, surprisingly, this challenges conventional wisdom. The stem cells that give rise to sperm have two slightly different copies of the genome. But sperm themselves have just one copy, containing a mix of the parental genomes.
2-13-19 Breast pumps may introduce harmful bacteria to babies’ gut microbiome
Using a breast pump may introduce babies to the “wrong” kind of bacteria, and perhaps increase their risk of childhood asthma. Shirin Moossavi at the University of Manitoba, Canada, and colleagues found milk from pumps contained higher levels of potentially harmful microbes than milk straight from the breast. “Increased exposure to potential pathogens in breast milk could pose a risk of respiratory infection in the infant,” says Moossavi. This might explain why infants fed pumped milk are at increased risk for paediatric asthma compared with those fed exclusively at the breast, she says. Exactly how bacteria become established in the infant gut is unclear. Microbes from the mother carried in breast milk is one probable route, but so is the transfer of mouth bacteria from the mouth of a sucking baby. Breast pumps offer a third, artificial pathway – one that can potentially transmit a range of environmental bacteria to the baby. For the study, the researchers looked for bacterial genes in breast milk samples from 393 healthy mothers three to four months after giving birth. The team found the bacterial content of milk being fed to the mothers’ babies differed greatly from infant to infant. Milk administered from breast pumps contained higher levels of potentially harmful “opportunistic pathogens”, such as those from the genus Stenotrophomonas and family Pseudomonadaceae. In contrast, direct breastfeeding without a pump was associated with microbes typically found in the mouth, as well as greater bacterial richness and diversity. This suggests infant mouth microbes play an important role in determining what kind of bacteria are found in mothers’ milk.
2-13-19 Slow sperm may fail at crashing ‘gates’ on their way to an egg
Narrow spots in the female reproductive tract could help weed out less desirable suitors. The female reproductive tract is an obstacle course that favors agile sperm. Narrow straits in parts of the tract act like gates, helping prevent slower-swimming sperm from ever reaching an egg, a study suggests. Using a device that mimics the tract’s variable width, researchers studied sperm behavior at a narrow point, where the sex cells faced strong head-on currents of fluid. The faster, stronger swimmers started moving along a butterfly-shaped path, keeping them close to the narrow point and upping the chances of making it through. Meanwhile, slower, weaker swimmers were swept away, the team reports online February 13 in Science Advances. “Narrow junctions of the tract may act as barriers” to poor swimmers, says coauthor Alireza Abbaspourrad, a biophysicist at Cornell University. The results suggest that this is a way that females select the healthiest sperm, he says. Sperm travel through the reproductive tract — the vagina, cervix, uterus and fallopian tubes — by swimming upstream against fluid flowing through the tract, which moves at different speeds along the way. Previous studies have shown that sperm tend to follow the walls of the tract to “steer” toward the egg, but haven’t investigated what effect the narrow spots might have on the trek. Through computer simulations and tests of sperm, Abbaspourrad and colleagues found that the fastest sperm, when stopped by the current at a narrow point, could make it back to a wall, swim along it and try again. Repeated, this movement resulted in a butterfly-shaped pattern. Whether a swimmer could get through ultimately depended on the speed of the fluid through the narrow point and the speed of a sperm.
2-13-19 How humans evolved to be both shockingly violent and super-cooperative
The origins of our paradoxical nature lie in murder and self-domestication. It's a weird story that may even explain why our species came into existence. ARE humans, by nature, good or evil? The question has split opinions since people began philosophising. Some, like the followers of Jean-Jacques Rousseau, say we are a naturally peaceful species corrupted by society. Others side with Thomas Hobbes and see us as a naturally violent species civilised by society. Both perspectives make sense. To say that we are both “naturally peaceful” and “naturally violent” seems contradictory, however. This is the paradox at the heart of my new book. The paradox is resolved if we recognise that human nature is a chimera. The chimera, in classical mythology, was a creature with the body of a goat and the head of a lion. It was neither one thing nor the other: it was both. I argue that, with respect to aggression, a human is both a goat and a lion. We have a low propensity for impulsive aggression, and a high propensity for premeditated aggression. This solution makes both Rousseauians and Hobbesians partially right, but it raises a deeper question: why did such an unusual combination of virtue and violence evolve? The story of how our species came to possess this unique mixture hasn’t been told before, and offers a rich and fresh perspective on the evolution of our behavioural and moral tendencies. It also addresses the fascinating but surprisingly neglected question of how and why our species, Homo sapiens, came into existence at all. Since the 1960s, efforts to understand the biology of aggression have converged on an important idea. Aggression – meaning behaviour intended to cause physical or mental harm – falls into two major types, so distinct in their function and biology that from an evolutionary viewpoint they need to be considered separately. I use the terms “proactive” and “reactive” aggression, but many other word pairs describe the same dichotomy, including cold and hot, offensive and defensive, premeditated and impulsive. To judge from other relevant animals, a high level of proactive aggression is normally associated with high reactive aggression. The common chimpanzee is the primate species that most often uses proactive aggression to kill its own kind, and it also has a high rate of reactive aggression within communities. The wolf’s proactive aggression against members of its own species is often lethal. As with chimpanzees, although relationships within wolf groups are generally benign and cooperative, they are far more emotionally reactive than dogs are. Lions and hyenas are also wolf-like in these respects.
2-13-19 Smart skin sticker could detect asthma attacks before they happen
A smart sticker that could alert people with asthma of an impending attack, has been made using a children’s toy. The device is made using Shrinky Dinks – plastic sheets that shrink to a fraction of their original size when heated. They are popular among children because they can be coloured and cut into shapes before shrinking. The Shrinky Dinks are used to shrink ultrathin metal sheets into stretch-detecting sensors that wirelessly transmit breathing data to a smartphone. The hope is that this data could be analysed to detect subtle changes in breathing rate that may be early signs of a worsening condition, or track improvements following medical treatment. It could be a useful tool for monitoring people with chronic lung conditions, such as asthma and cystic fibrosis, says Michelle Khine at the University of California, Irvine, who led the team. People will use the device by sticking it to their lower ribs. The device monitors changes in electrical resistance as it stretches and retracts on the skin. When the wearer is still, the sensor’s measurements are as good as a medical-grade spirometer – a machine that measures lung volume from how much a person breathes out in a forced breath, says Michael Chu, one of the team. Spirometry is still the most accurate approach, but the new method has the advantage of continuous monitoring over time. Currently, the sensor becomes less accurate when the wearer is very active, for example if they are running. Khine says the next step is to use the device to try to predict asthma attacks before they happen.
2-11-19 AI can diagnose childhood illnesses better than some doctors
Diagnosing an illness requires taking in a lot of information and connecting the dots. Artificial intelligence may be well-suited to such a task and in recent tests one system could diagnose children’s illnesses better than some doctors. Kang Zhang at the University of California in San Diego and his colleagues trained an AI on medical records from 1.3 million patient visits at a major medical centre in Guangzhou, China. The patients were all under 18 years old and visited their doctor between January 2016 and January 2017. Their medical charts include text written by doctors and laboratory test results. To help the AI, Zhang and his team had human doctors annotate medical records to identify portions of text associated with the child’s complaint, their history of illness, and laboratory tests. When tested on previously unseen cases, the AI could diagnoseglandular fever (also known as mononucleosis), roseola, influenza, chicken pox and hand-foot-mouth disease with between 90 and 97 per cent accuracy. It’s not perfect, but neither are human doctors, says Zhang. “When you’re busy you can see 80 patients a day. And you can only grasp so much information. That’s where we potentially as human physicians might make mistakes. AI doesn’t have to sleep, it has a large memory and doesn’t lose energy,” he says. The team compared the model’s accuracy to that of 20 paediatricians with varying years of experience. It outperformed the junior paediatricians, though the senior ones did better than the AI. The AI could be used to triage patients in emergency departments. “Given sufficient data, AI should be able to tell if this is an urgent situation and needs referral or if it’s a cold,” says Zhang.
2-11-19 Congo’s Ebola outbreak is a testing ground for new treatments.
The four different drugs include three antibody treatments and one antiviral. Amid the second largest Ebola outbreak ever, the hunt for a lifesaving treatment is on. A clinical trial of patients taking place now in Congo is gathering evidence on experimental therapies, to provide a proven option when the deadly virus inevitably emerges again. The first multidrug clinical trial of Ebola therapies, which began enrolling patients in November, will compare the effectiveness of three different antibody treatments and one antiviral drug. One therapy tested briefly during the 2014–2016 outbreak in West Africa, the largest ever, has already shown promise. With the trial data, though, “we’ll be able to say, ideally, that this drug or that drug actually does work, not just we think or hope it does work,” says Richard Davey, one of the principal trial investigators and the deputy clinical director at the U.S. National Institute of Allergy and Infectious Diseases in Bethesda, Md. Ebola virus causes severe illness, including fever, vomiting, diarrhea and bleeding. Death rates range from 25 to 90 percent, depending on the outbreak. During Congo’s current outbreak — the country’s 10th and its largest since Ebola was discovered within its borders in 1976 — about 63 percent of those infected have died, or 510 out of the 811 cases reported as of February 9. Stopping the outbreak, which began August 1, has been difficult due to security risks and armed conflict in the region, as well as public mistrust of the medical response, the World Health Organization says.
2-11-19 Sailors spread the ancient fashion for monuments like Stonehenge
Thousands of ancient stone structures, such as Stonehenge, are found throughout Europe. Now a long-standing puzzle of where the practise originated and how it spread has been solved. Over the last century there have been two main views on the origins of the stone structures, known as megaliths. One was that they started from a single source then spread over sea routes. The other was that megalith construction developed independently in different locations. To find out which was correct, Schulz Paulsson of the University of Gothenburg, Sweden and colleagues analysed the dates from over 2000 megaliths in Europe. They used statistical methods to narrow down previous estimations and get a better picture of where they built and in what order. The team found that megalith construction started in a single location in northwest France over a period of 200-300 years around 4500 BC. The tradition then spread through Europe spanning 2,000 years along the sea routes of the Mediterranean and Atlantic coasts, concentrated in coastal regions. The pattern of how the megaliths spread over time also hints that societies developed sophisticated sea-faring technology, far earlier than previously thought. “They were moving over the seaway, taking long distance journeys along the coasts,” says Schulz Paulsson. This fits with other research she has carried out on megalithic art in Brittany, which shows engravings of many boats, some large enough for a crew of 12. The previous view was that large boats capable of travelling long distance were only developed in the Bronze Age, some 2000 years later.
2-11-19 The spread of Europe’s giant stone monuments may trace back to one region
Ancient sea travelers carried the knowledge of how to build megaliths from France. From simple rock arches to Stonehenge, tens of thousands of imposing stone structures dot Europe’s landscapes. The origins of these megaliths have long been controversial. A new study suggests that large rock constructions first appeared in France and spread across Europe in three waves. The earliest megaliths were built in what’s now northwestern France as early as around 6,800 years ago, says archaeologist Bettina Schulz Paulsson of the University of Gothenburg in Sweden. Knowledge of these stone constructions then spread by sea to societies along Europe’s Atlantic and Mediterranean coasts, she contends in a study posted online the week of February 11 in the Proceedings of the National Academy of Sciences. “European megaliths were products of mobile, long-distance sea travelers,” Schulz Paulsson says. Around 35,000 megalithic graves, standing stones, stone circles and stone buildings or temples still exist, many located near coastlines. Radiocarbon dating has suggested that these structures were built between roughly 6,500 and 4,500 years ago. Scholars a century ago thought that megaliths originated in the Near East or the Mediterranean area and spread elsewhere via sea trading or land migrations by believers in a megalithic religion. But as absolute dates for archaeological sites began to emerge in the 1970s, several researchers argued that megaliths emerged independently among a handful of European farming communities.
2-11-19 Controversial fossils suggest life began to move 2.1 billion years ago
Burrow-like structures several millimetres in diameter have been found in 2.1-billion-year-old rocks in Gabon, Africa. The structures were made by a moving lifeform of some kind, claim geologist Abderrazak El Albani at the University of Poitiers in France and his team. The team do not know what made the trace fossils, but they speculate that it could be something similar to colonial amoeba or slime moulds – organisms made of cells that normally live separately. The trace fossils were found near bacterial mats that the mysterious lifeforms may have been feeding on. “It’s truly amazing,” says El Albani. Previously, the earliest evidence of moving lifeforms was just a half a billion years old. There are burrows and tiny footprints in rocks of this age, probably left by small animals. The 2.1-billion year-old burrows are very unlikely to have been produced by organisms as complex as animals, which probably appeared only between about 850 and 650 million years ago. In fact, it’s not even clear that organisms as complex as amoeba were around 2.1 billion years ago: they are eukaryotes, and the oldest eukaryotic fossils found so far are about 1.7 billion years old. So if El Albani’s interpretation is correct, these finds challenge the conventional story of life’s evolution. On the other hand, it’s clear that multicellularity evolved on numerous different occasions. There are even multicellular organisms composed of simple – prokaryotic – cells. And lab experiments suggest it’s relatively easy for cells to evolve multicellularity. In 2010, El Albani reporting finding what his team think are fossils of multicellular organisms in the same sedimentary rocks in the Franceville basin in Gabon, which formed in a warm, shallow ocean 2.1 billion years ago. “It’s a unique place in the world, where we have this preservation of the rocks,” he says. Most rocks are of this age have been metamorphosed by extreme heat and pressure. Since then, his team have continued to make field trips and have collected more than 500 specimens – now including the apparent trace fossils. These organisms lived at the time when oxygen levels were relatively high, says El Albani. Shortly after oxygen level plummeted and remained low for a billion years – the “Boring Billion”. So El Albani thinks complex lifeforms started to evolve much earlier than thought, but were then killed off. “These organisms disappeared,” he says.
2-11-19 A rare, ancient case of bone cancer has been found in a turtle ancestor
An extinct ancestor of modern turtles called Pappochelys rosinae had bone cancer, the oldest known case in an amniote, a group that includes mammals, birds and reptiles. A 240-million-year-old case of bone cancer has turned up in a fossil of an extinct ancestor of turtles. Dating to the Triassic Period, the fossil is the oldest known example of this cancer in an amniote, a group that includes mammals, birds and reptiles, researchers report online February 7 in JAMA Oncology. The fossilized left femur from the shell-less stem-turtle Pappochelys rosinae was recovered in southwestern Germany in 2013. A growth on the leg bone prompted a team of paleontologists and physicians to analyze the fossil with a micro CT scan, an imaging technique that provides a detailed, three-dimensional view inside an object. “When we saw that this was not a break or an infection, we started looking at other growth-causing diseases,” says Yara Haridy, a paleontologist at the Museum für Naturkunde in Berlin. The verdict? Periosteal osteosarcoma, a malignant bone tumor. “It looks almost exactly like human periosteal osteosarcoma,” Haridy says. “It is almost obvious that ancient animals would have cancer, but it is so very rare that we find evidence of it,” she says. The discovery of this tumor from the Triassic offers evidence that cancer is “a vulnerability to mutation deeply rooted in our DNA.”
2-10-19 How we evolved to love horror movies
Being terrified might actually have its benefits. Bird Box was the first breakout film of the new year. The post-apocalyptic thriller was watched by more than 26 million people over its first week on Netfilx, a record for the streaming service. It comes on the heels of last year's A Quiet Place, which was one of the top-grossing films of 2018. Movies such as these have a single mission: To terrify their viewers. But why do so many people choose to spend two hours in perpetual fear? New research provides a clear answer: We are evolutionarily wired to seek out such material. A research team led by Mathias Clasen of Denmark's Aarhus University argues horror movies, novels, and video games fall into the category of "benign masochism." "Horror movies tend to imaginatively transport consumers into fictional universes that brim with dangers," the researchers write. "Through such imaginative absorption, people get to experience strong, predominantly negative emotions within a safe context. This experience serves as a way of preparing for real-world threat situations." The study, in the journal Evolutionary Behavioral Sciences, featured 1,070 Americans recruited online. All completed surveys designed to measure their personality traits, propensity for sensation-seeking, and belief in paranormal phenomena. They also reported how much they enjoy horror movies, books, and games; how frequently they were exposed to such material; and whether they prefer such films to be intensely or merely moderately scary. As recent successes like Bird Box suggest, horror is far from a niche market, and more than 54 percent of the study's participants either agreed or strongly agreed with the statement "I tend to enjoy horror media." Only 14 percent strongly disagreed.
2-10-19 Brain-zapping implants that fight depression are inching closer to reality
Researchers are resetting the part of the brain that can shift mood. Like seismic sensors planted in quiet ground, hundreds of tiny electrodes rested in the outer layer of the 44-year-old woman’s brain. These sensors, each slightly larger than a sesame seed, had been implanted under her skull to listen for the first rumblings of epileptic seizures. The electrodes gave researchers unprecedented access to the patient’s brain. With the woman’s permission, scientists at the University of California, San Francisco began using those electrodes to do more than listen; they kicked off tiny electrical earthquakes at different spots in her brain. Most of the electrical pulses went completely unnoticed by the patient. But researchers finally got the effect they were hunting for by targeting the brain area just behind her eyes. Asked how she felt, the woman answered: “Calmer in my nerves.” Zapping the same spot in other participants’ brains evoked similar responses: “I feel positive, relaxed,” said a 53-year-old woman. A 60-year-old man described “starting to feel a little more alive, a little more energy.” With stimulation to that one part of the brain, “participants would sit up a little straighter and seem a little bit more alert,” says UCSF neuroscientist Kristin Sellers. Such positive mood changes in response to light neural jolts, described in the Dec. 17 Current Biology, bring researchers closer to an audacious goal: a device implanted into the brains of severely depressed people to detect a looming crisis coming on and zap the brain out of it.
2-8-19 Brain scans decode an elusive signature of consciousness
An international research effort finds patterns of brain activity that come with awareness. A conscious brain hums with elaborate, interwoven signals, a study finds. Scientists uncovered that new signature of consciousness by analyzing brain activity of healthy people and of people who were not aware of their surroundings. The result, published online February 6 in Science Advances, makes headway on a tough problem: how to accurately measure awareness in patients who can’t communicate. Other methods for measuring consciousness have been proposed, but because of its size and design, the new study was able to find a particularly strong signal. Conducted by an international team of researchers spanning four countries, the effort “produced clear, reliable results that are directly relevant to the clinical neuroscience of consciousness,” says cognitive neuroscientist Michael Pitts of Reed College in Portland, Ore. Consciousness — and how the brain creates it — is a squishy concept. It slips away when we sleep, and can be distorted by drugs or lost in accidents. Though scientists have proposed many biological explanations for how our brains create consciousness, a full definition still eludes scientists.
2-8-19 Screen time could hurt kids’ development
Parents who let their young children spend lots of time in front of TVs and tablets risk slowing their kids’ development, a new study has warned. Researchers in Canada tracked nearly 2,500 children ages 2 to 5 and asked their mothers to report how many hours a day, on average, their child looked at screens. The moms also answered questions on their kids’ communication skills, behavior, and social interactions. Researchers found that, on average, the children spent two to three hours a day in front of screens; the American Academy of Pediatrics recommends that young children watch only one hour of quality programming a day. And the more time the children spent looking at screens at ages 2 and 3, the worse they did in developmental tests at ages 3 and 5. The study had some limitations—most data was self-reported by the mothers—and the authors emphasize that correlation does not mean causation. But they suggest that the differences in development could be because kids who bury their heads in screens miss out on opportunities to practice and refine their communication, social, and motor skills—by playing with toys, for example, or interacting with family and friends. Parents can think of screen time as they do junk food, study leader Sheri Madigan, from the University of Calgary, tells Time.com. “In small doses, it’s OK, but in excess, it has consequences.”
2-8-19 Blood pressure and brain volume
Scientists have long thought that high blood pressure takes decades to affect the brain. But a new study suggests that young adults with elevated blood pressure also often show signs of brain shrinkage. Researchers recruited 423 people ages 19 to 40, who underwent an MRI brain scan and at least one blood pressure reading. They found that participants with higher blood pressure readings—even within the 120-140 systolic range, which is generally considered normal—had less gray matter volume in several areas of the brain than those whose readings were under 120. The finding counters the assumption that brain-volume changes happen only in older people with hypertension. “This is a gradual change that probably happens throughout life, and ends where people have a stroke or cognitive decline,” lead author H. Lina Schaare, from the Max Planck Institute in Leipzig, Germany, tells The New York Times. “A blood pressure around 130 in young people is not necessarily benign.” Schaare now wants to examine whether reduced gray matter volume at an early age can increase risk of stroke, dementia, and other conditions.
2-8-19 The genes that make night owls
Late risers are genetically predisposed to needing a lie-in—and may be more likely to suffer mental health problems as a result. That’s the conclusion of a major new study that examined the genetics of some 700,000 people in the U.S. and U.K. By looking at how participants described themselves—a “morning person” or an “evening person”—researchers identified 351 genes associated with early rising. Previous research identified only 24 such genes. When researchers then looked for links to mental health issues, they found that night owls were about 10 percent more likely than early risers to develop schizophrenia, had a higher risk of depression, and reported being less happy on well-being questionnaires. Study leader Samuel Jones, from the U.K’s University of Exeter, says the 351 genes he and his team identified may affect how a person’s brain reacts to external light signals. “These small differences may have potentially significant effects on the ability of our body clocks to keep time effectively,” he tells The Guardian (U.K.). Jones says it remains unclear why night owls may be more susceptible to mental health issues, but suggests it could be because they have to work against their natural circadian rhythms in school and at work.
2-8-19 A superbug’s global spread
In a worrying sign of how far and fast so-called superbugs are spreading, an antibiotic-resistant gene first discovered in India has been found in a remote region of the Arctic. Antibiotic resistance is a growing global health concern: At least 700,000 people die from superbug infections each year. And as more bacteria evolve to fight off antibiotics—a phenomenon fueled by their overuse in medicine and farming—that annual death toll could hit 10 million by 2050. To study the global spread of superbugs, researchers took soil samples from eight locations in Svalbard, a frozen Norwegian archipelago in the high Arctic, and then analyzed the DNA of bacteria and other organisms in the earth. A gene linked to multidrug resistance, first observed in a hospital patient in India in 2008, was found in more than 60 percent of the samples. Scientists believe the superbug arrived in the Arctic in the fecal matter of migrating birds or human visitors. Study leader David Graham, from the U.K.’s Newcastle University, tells ScienceDaily.com that the discovery confirms that “solutions to antibiotic resistance must be viewed in global rather than just local terms.”
2-8-19 The Goodness Paradox: The Strange Relationship Between Virtue and Violence in Human Evolution
“If we are so good, how can we be so bad?” asked John Hawks in The Wall Street Journal. Thinkers have puzzled over humans’ contradictory nature for ages, and for anyone who’s pondered how we can be both unusually docile and murderous on a grand scale, Richard Wrangham’s new book is “essential reading.” The Harvard anthropologist, who first gained notoriety two decades ago by arguing that humans are intrinsically violent, also agrees with researchers who claim that the species has become gradually less violent. In The Goodness Paradox, Wrangham argues that the change occurred because we “self-domesticated,” and did so in an unusual way: Our ancestors punished alpha-male bullies by working cooperatively to execute them. Over time, the capacity to cooperate became the more prevalent trait. So score one for capital punishment, said Tom Whipple in The Times (U.K.). But note that Wrangham personally opposes the execution of violent individuals today, and he isn’t claiming that today’s humans, including the beta males who won the evolutionary battle, are saints. The capacity to cooperate, after all, amplifies the human capacity for war and genocide. Wrangham prefers focusing on the evolutionary record, beginning with our two closest primate cousins, said Rachel Newcomb in The Washington Post. Whereas chimpanzees are notoriously aggressive, bonobos are the opposite, and Wrangham claims that the latter species self-domesticated because they had less need for aggression in their resource-rich native habitat. The proposition that humans and bonobos both self-domesticated is backed by shared physical evolutionary changes: Both became milder and more childlike in appearance over time, presumably as they grew more cooperative. But does capital punishment have to be the key to the human story? asked anthropologist Melvin Konner in The Atlantic. I once spent two years amid a hunter-gatherer group, the !Kung of southern Africa, and found that women, when afforded power equal to or greater than men’s in a culture, will choose men of calm temperament as their mates, thus reducing the group’s propensity for aggressiveness over time. But of course Wrangham’s thesis provokes argument; “that’s what bold theorizing is supposed to do.” Over the course of a long career, he has come up with some of the boldest and best ideas about human evolution, and now he has done it again. The Goodness Paradox highlights a puzzle about our history that can’t be ignored, and reminds us that violence and virtue live together within us.
2-8-19 Tyrannosaurus rex might have accidentally helped fruit grow
The king of the dinosaurs may have been an accidental gardener. Tyrannosaurus rex was a famed carnivore, but it seems it may also have spread fruit seeds, as a result of gobbling down plant-eating prey. Many plants rely on animals to disperse their seeds. They produce seeded fruits to attract herbivores which consume the fruit and defecate the seeds. Carnivores, which have no interest in fruit, can also end up with seeds in their dung from eating herbivores. Tetsuro Yoshikawa at National Institute for Environmental Studies in Tsukuba, Japan wondered if the same was true during the Cretaceous period. He and his colleagues used information on the body weight and diet of 51 living bird species, T. rex’s closest living relatives, to build a computer model that estimates how long seeds are retained in a bird’s gut before being expelled. The team used this model to predict how long seeds would stay inside a T. rex. They found that seeds would probably stick around for five to seven days before passing through its digestive system. Considering T. rex was highly mobile, Yoshikawa says this could mean the dinosaur dispersed seeds over a wide area. A lot more work is needed to understand T. rex’s role in seed dispersal, says Yoshikawa. “Our result is a first step to the modelling, and the estimates for dinosaurs are quite rough.” Other factors that would improve the model include the type of seeds ingested and an understanding of T. rex’s overall diet, says Yoshikawa, but the limited information we have on dinosaurs makes this very difficult.
2-8-19 Beer before wine or wine before beer: the hangover is the same
Drinking beer before wine won’t save you from a hangover. This is according to rigorous tests performed with 90 volunteers. The idea of the study was to test the old adage: “beer before wine and you’ll feel fine; wine before beer and you’ll feel queer.” Similar sayings exist in French and German. The participants, aged between 19 and 40, were split into three groups. The first group drank beer until their breath alcohol concentration reached 0.05 per cent, then drank white wine until their breath alcohol reached 0.11 per cent. In the second group, the two drinks were switched. People in these two groups typically drank around 1.3 litres of beer and 600 millilitres of wine. The third group drank only beer or only wine. A week later, the experiment was repeated, with the first and second groups switched. The non-mixers who drank beer switched to wine and vice versa. The next day, they completed a questionnaire about their hangover symptoms, including headache, fatigue, thirst, dizziness and nausea. There were no significant differences between any of the three groups, suggesting not only that there is no safe order for mixing drinks, but sticking to one drink isn’t much help either. Vomiting and self-rated drunkenness the night before correlated with hangover scores in the morning, but other factors, such as age and sex, did not have a significant effect. The only way to avoid a hangover is not to drink as much, says Kai Hensel at the University of Cambridge, UK. “After doing 360 blood and urine tests and spending almost £10,000 on lab analysis, the predictor is asking people how drunk are you and do you have to vomit.”
2-7-19 In some cases, getting dengue may protect against Zika
What happened in a hard-hit Brazilian slum suggests timing of dengue infections may matter. Previous infections with dengue virus may have protected some people in an urban slum in Brazil from getting Zika. In a study of more than 1,400 people in the Pau da Lima area of Salvador, those with higher levels of antibodies against a particular dengue virus protein were at lower risk of contracting Zika, researchers report in the Feb. 8 Science. “The higher the antibody, the higher the protection,” says Albert Ko, an infectious disease physician and epidemiologist at the Yale School of Public Health. That finding contrasts with previous studies in mice and in cells grown in lab dishes, in which antibodies against dengue seemed to make Zika worse (SN: 5/29/17, p. 14). Ko and other researchers had been tracking a rat-borne bacterial illness in the poverty-stricken neighborhood for two years when the Zika outbreak hit in 2015. “We were at the epicenter of the pandemic,” Ko says. Blood samples taken every six months enabled researchers to track people there before, during and after the outbreak. Zika infected an estimated 73 percent of people in the slum but “it really, really varied geographically,” says Isabel Rodriguez-Barraquer, an epidemiologist at the University of California, San Francisco. In some areas of the 0.17-square-kilometer community, 83 percent of people were infected. In other pockets, just 29 percent were.
2-7-19 DNA reveals early mating between Asian herders and European farmers
The finding might rewrite the origins and spread of key cultural innovations and languages. Hundreds of years before changing the genetic face of Bronze Age Europeans, herders based in western Asia’s steppe grasslands were already mingling and occasionally mating with nearby farmers in southeastern Europe. That surprising finding, published online February 4 in Nature Communications, raises novel questions about a pivotal time when widespread foraging and farming populations interacted in Eurasia’s Caucasus region. Those exchanges presumably sparked the geographic spread of metalworking, the wheel and wagon, and Indo-European languages still spoken in much of the world. Archaeologists have often assumed that, as early as around 5,600 years ago, Caucasus farmers known as the Maykop migrated north in big numbers, bringing metalworking and early Indo-European tongues to herders who roamed grasslands on the edge of the region. In that scenario, this cultural exchange led steppe herders to develop a horse-and-wagon lifestyle that the nomads later transported to Europe and Asia, along with Indo-European languages, starting about 5,000 years ago (SN: 11/25/17, p. 16). Researchers call those mobile herders Yamnaya people. An ancient DNA analysis unexpectedly found signs of mating more than 5,000 years ago between western Asian Yamnaya herders and European farmers, possibly from the Globular Amphora Culture. In another surprise, Maykop farmers thought by many researchers to have dramatically influenced Yamnaya culture left no genetic mark on the herders. The dotted lines represent the suspected spheres of influence exercised by the Globular Amphora Culture and the Maykop people in Yamnaya territory.
2-7-19 Voting systems that let losing side win may increase overall happiness
In a democratic election, the winning side is the one that gets the most votes – at least, normally. A test of alternative voting systems has found that in some cases, it is actually possible to increase overall satisfaction by delivering a result in which a minority decision prospers. Alessandra Casella of Columbia University and Luis Sanchez of Cornell University in New York tested two voting systems in a survey ahead of a state-wide Californian ballot in 2016. Rather than one vote per person, the systems – known as storable and quadratic votes – give people multiple votes to allocate to a range of issues. “The ingenuity of the voting schemes is that they induce the voter to reveal her priorities sincerely,” says Casella. The researchers asked 600 California residents about four issues that were likely to be included on the ballot. They selected issues that were unlikely to result in a landslide, but about which some voters would feel strongly – such as requiring law enforcement to report undocumented immigrants. Survey respondents were first asked to rate how important each issue was to them, and how they would vote in each proposal (in favour, opposed, or abstain). For storable votes, participants were then granted one extra vote to support a proposition that they felt strongly about. For quadratic voting, respondents were given a choice of extra, weighted votes to express their strength of feeling. For example, a voter could choose to cast an additional vote on each proposal, each weighted as 1, or to cast only one additional vote on a single issue, but with a weight of 2. These priorities were factored into the final outcome by counting the weighted number of cast votes, rather than the total number of voters, to reach a majority.
2-7-19 New Tonga island 'now home to flowers and owls'
Scientists have found signs of life on one of the world's newest islands, just four years after it was spawned by a volcanic eruption. Unofficially known as Hunga Tonga-Hunga Ha'apai, it lies in the kingdom of Tonga, and is already nurturing pink flowering plants, sooty tern birds, and even barn owls. Tonga is made up of over 170 islands in the Pacific Ocean, east of Australia. A team from the Sea Education Association and Nasa visited the small land mass in October, having previously kept watch through satellite imaging. Hunga Tonga-Hunga Ha'apai - named after the two islands it is nestled between - was born in December 2014 after a submarine volcano erupted, sending a stream of steam, ash and rock into the air. When the ash finally settled, it interacted with the seawater and solidified. A month later, the new island was formed. It isn't uncommon for underwater volcanic eruptions to form little islands, but they usually have shorter life-spans. Hunga Tonga-Hunga Ha'apai is one of just three to emerge in the last 150 years that have lasted more than a few months. "In this case, the ash seemed to have a chemical reaction with the seawater that allowed it to solidify more than it usually would," volcanologist Jess Phoenix told the BBC. She compares the island to Surtsey, an island in Iceland that was formed in a similar way in the 1960s, and is still around today. Nasa researcher Dan Slayback was among those who visited the island in October, and said they were "all like giddy school children". He found a light-coloured, sticky clay mud on the volcanic mass - something that left him mystified. "We didn't really know what it was and I'm still a little baffled of where it's coming from," Mr Slayback said in a recent Nasa blog post.
2-7-19 Evolutionarily, grandmas are good for grandkids — up to a point
Women may live past their reproductive years because they help their grandchildren survive. Grandmothers are great — generally speaking. But evolutionarily speaking, it’s puzzling why women past their reproductive years live so long. Grandma’s age and how close she lives to her grandchildren can affect those children’s survival, suggest two new studies published February 7 in Current Biology. One found that, among Finnish families in the 1700s–1800s, the survival rate of young grandchildren increased 30 percent when their maternal grandmothers lived nearby and were 50 to 75 years old. The second study looked at whether that benefit to survival persists even when grandma lives far away. (Spoiler: It doesn’t.) The studies are part of a broader effort to explain the existence of menopause, a rarity in the animal kingdom. The so-called “grandmother hypothesis” stipulates that, from an evolution standpoint, women’s longevity is due to their contributions to their grandkids’ survival, thus extending their own lineage (SN: 3/20/04, p. 188). In the Finnish study, researchers wanted to know if grandmas eventually age out of that beneficial role. The team used records collected on the country’s churchgoers born from 1731 to 1895, including 5,815 children. Women at that time had large families, averaging almost six children, with about a third of kids dying before age 5. The team found that when maternal grandmothers living nearby were aged 50 to 75, their 2- to 5-year-old grandchildren had a 30 percent higher likelihood of survival than children whose maternal grandmothers were deceased. Similarly aged paternal grandmothers and maternal grandmothers aged past 75 did not affect children’s overall survival.
2-6-19 The truth about generations: Why millennials aren’t special snowflakes
We increasingly form opinions about people based on the generation they belong to, but these labels are often lacking in science. PEOPLE born between the mid-80s and early 2000s have been called many things: Generation Y, the Net Generation and, more usually, millennials. Now, a new name is growing in popularity: the Burnout Generation. The argument, laid out in a viral BuzzFeed article last month, is that growing up, millennials were unduly affected by the financial crisis of the late 2000s and pressured by a new wave of intensive parenting. As a result, they are uniquely overambitious, overworked and overwhelmed. The description rang true to many millennial readers, but also left a lot of people in the previous cohort, Generation X, wondering why no one was paying attention to the difficulties they face. This disparity exposes the looseness with which we talk about generations. So is it even useful to divide people up in this way? “If you want to draw a boundary between two historical generations, there needs to be a reason for it,” says Elwood Carlson, a sociologist at Florida State University. Generally, that should be a collective difference between the two groups that can be identified empirically, he says. It isn’t clear whether “burnout” fulfils that criteria, but it might. “Deciding which differences are important for separating generations is more of an art than a science,” says Carlson. The study of generations took off in the 1920s, when sociologist Karl Mannheim posited that youths experiencing major events and rapid social change form more cohesive generations. Merely coexisting isn’t enough to produce a generational consciousness, he argued.
2-6-19 Why some children may get strep throat more often than others
Tonsil tissue from kids with recurring infections have smaller key immune structures. For kids, getting strep throat again and again is a pain. It’s also a problem little understood by scientists. Now a study that analyzed kids’ tonsils hints at why such repeat infections may happen. Children with recurrent strep infections had smaller immune structures crucial to the development of antibodies in their tonsils than kids who hadn’t had repeated infections, researchers found. The frequently sore-of-throat were also more susceptible to a protein, deployed by the bacteria that cause the infection, that disrupts the body’s immune response, the team reports online February 6 in Science Translational Medicine. Globally each year, there are an estimated 600 million cases of strep throat, which commonly produces a sore throat and fever. Doctors treat the illness with antibiotics, especially in children, who are at highest risk of developing rheumatic fever and heart problems from a strep infection. But some kids, even though they get treatment, repeatedly develop new cases of strep throat. In the study, immunologist Shane Crotty of the La Jolla Institute for Immunology in California and colleagues examined tonsils, the immune tissue found at the back of the throat, that had been removed from 5- to 18-year-olds. Some of the children had their tonsils taken out because of recurrent strep infections. Others had their tonsils removed to resolve sleep apnea caused by enlarged tonsils; this group was a proxy for kids not plagued by repeated bouts of strep.
2-6-19 Recommended time between smear tests could increase thanks to HPV test
A new approach for cervical cancer screening set to begin this year in the UK could let women safely wait longer between tests. Existing forms of screening, sometimes known as the smear or pap test, involve brushing some cells from the neck of the cervix and examining them under a microscope to see if any look precancerous. In the UK, women are advised to have this test every three years from the ages of 25 to 49, and every five years between 50 and 64. But a different method of testing will be introduced in the UK this year. This method removes some cells in the same way, but these are then tested for the human papillomavirus (HPV). This virus is a common sexually transmitted infection which can cause cervical tumours plus other types of cancer. Samples found to have the virus will then be checked for precancerous cells in the standard way. In a trial in nearly 600,000 women, Matejka Rebolj at Kings College London and her team found that viral testing with five-yearly checks was more sensitive than more regular screening with the old-style smear test, finding up to 50 per cent more cases of people with precancerous cells. The new test is being introduced this year, based on early results from the same trial. The UK’s National Screening Committee is currently consulting on whether to also extend the interval between tests to five years for all women who test negative. Other countries, such as Australia and the Netherlands, have already switched over, while the US does both tests in tandem.
2-6-19 Virus lurking inside banana genome has been destroyed with CRISPR
GENOME editing has been used to destroy a virus lurking inside many bananas grown in Africa. Other teams are trying to use the technique to make Cavendish bananas, a commercial variety sold in supermarkets worldwide, resistant to another disease. The banana streak virus, spread by insects, integrates its DNA into the banana’s genome. In places like west Africa, where bananas are a staple food, most varieties now have the virus inside them. When crops are stressed, it emerges from dormancy and can destroy plantations. There’s nothing farmers can do. But Leena Tripathi at the International Institute of Tropical Agriculture in Kenya has now used the CRISPR genome editing method to target and destroy the viral DNA inside the genome of a banana variety called Gonja Manjaya. The plan is to breed virus-free plants for African farmers. Her team is also using CRISPR to make the bananas resistant to the virus, so they aren’t simply re-infected (Communications Biology, doi.org/cz8k). The banana streak virus doesn’t infect the popular Cavendish variety. But a fungal infection called Tropical Race 4 is devastating Cavendish plantations. Because the Cavendish is a sterile mutant that can only be propagated by cloning, there is no way to breed resistant varieties. Instead, several teams worldwide are trying to use CRISPR to make it resistant to Tropical Race 4.
2-6-19 When did the kangaroo hop? Scientists have the answer
Scientists have discovered when the kangaroo learned to hop - and it's a lot earlier than previously thought. According to new fossils, the origin of the famous kangaroo gait goes back 20 million years. Living kangaroos are the only large mammal to use hopping on two legs as their main form of locomotion. The extinct cousins of modern kangaroos could also hop, according to a study of their fossilised foot bones, as well as moving on four legs and climbing trees. The rare kangaroo fossils were found at Riversleigh in the north-west of Queensland in Australia. The site is a treasure trove of animal remains, including marsupials, bats, lizards, snakes, crocodiles and birds. "It's one of the few snapshots we have of the evolution of marsupials in Australasia in deep time," said study researcher Dr Benjamin Kear, of Uppsala University in Sweden. Kangaroos can quickly cover large distances using their distinctive gait, which is most effective in open habitats such as deserts and grasslands. The long-held view has been that the animals evolved the ability to hop to take advantage of a change in the climate, which brought drier conditions and the spread of grasslands. However the research, published in the journal Royal Society Open Science, suggests the story isn't that simple. Geometric modelling shows the ancient extinct cousins of modern kangaroos could use the same range of gaits as living kangaroos. Evidence, say the scientists, that the kangaroo has had the ability to hop for many millions of years. "It all points towards an extremely successful animal, that's superbly adapted to its environment and a whole range of habitats and ecosystems and it's why kangaroos are so successful today," said Dr Kear. "It's one of the most biologically weird and wonderful animals you're likely to find."
2-6-19 What FamilyTreeDNA sharing genetic data with police means for you
Law enforcement can now use the company’s private DNA database to investigate rapes and murders. A popular at-home DNA testing company has announced that it is allowing police to search its database of genetic data just as customers do when looking for family members. But there’s one big difference: Police are trying to track down rape and murder suspects using relatives’ DNA. Since Joseph James DeAngelo was arrested as the suspected Golden State Killer last April, police have announced the identification of suspects in at least 25 cold cases, including five in January (SN Online: 4/29/18). Until now, law enforcement agencies had mostly used a public database called GEDMatch for these “genetic genealogy” investigations. But FamilyTreeDNA has granted police permission to upload data from crime scene DNA and search the company’s more than 1 million records to look for relatives of potential suspects. While some people support the company’s effort to help catch suspected rapists and murderers, privacy advocates and some customers of DNA testing services are alarmed by the idea that police could poke around in people’s genetic data. Here’s what the announcement really means. Police are interested in determining how much DNA people in the database share with genetic samples from crime scenes. Genealogists can then use the closest matches possible to build family trees and identify a likely suspect. The process is similar to looking at someone’s LinkedIn profile to see who is in the person’s social network, says Melinde Lutz Byrne, a forensic genealogist at Boston University who is involved in helping law enforcement solve rape and murder cases.
2-6-19 Trump wants to end HIV infections by 2030 – here’s how to do it
During his State of the Union address on 5 February, US president Donald Trump announced a goal of ending HIV transmission in the US by 2030. “Scientific breakthroughs have brought a once-distant dream within reach,” he said. “Together, we will defeat AIDS in America.” Trump didn’t lay out a specific amount of money that his next budget would dedicate to the cause, but said the initiative would be included in his request to Congress for funding. At the height of the AIDS epidemic in the early 1990s, Americans were being diagnosed with HIV at a rate of between 650,000 and 900,000 people per year. With new medicines and increased awareness of the risk of transmitting HIV, new infections have decreased since then, plateauing for the last several years to around 50,000 people per year. There is some way to go, then, to achieve elimination. The US isn’t alone in this ambitious target. On 30 January, the UK announced the same goal, and in 2014 the Joint United Nations Programme on HIV and AIDS set a similar target with key milestones in the coming years. The UN strategy is a global one that aims to have most people living with HIV diagnosed and on antiretroviral treatment by 2020, and to maintain suppression of the virus until 2030. If that happens, the number of new infections and transmissions globally would be so low that we could effectively say the epidemic had been eliminated. To meet the UN goal, the US would have to show that 73 per cent of people with HIV have their infection under control by 2020. “Are we on track to achieve that target? As best I can tell it’s certainly possible,” says Jessica Justman at Columbia University.
2-6-19 DNA-eating bacteria lurk beneath the Atlantic Ocean floor
For a few species of microbe, DNA is more than a library of genetic information: it’s also lunch. Some bacteria that live in the mud below the seafloor appear to survive by eating DNA trapped in the dirt. “This is one of the yummiest things to eat down there,” says Gustavo Ramírez at the University of Southern California. “It’s got the major macronutrients that you get in your lawn fertiliser – carbon, nitrogen and phosphorus.” Biologists have already established that seafloor mud contains naked DNA – molecules no longer locked away inside biological cells. But the fact that this ‘extracellular’ DNA doesn’t build up into really substantial quantities suggests it must be recycled, says Kenneth Wasmund at the University of Vienna, Austria. That could be because some of the bacteria living in the mud break it down and reuse its components, he says. To find out, Wasmund and his colleagues collected samples of mud from the bottom of Baffin Bay in the North Atlantic Ocean. Back in the lab, they placed the mud samples in anaerobic conditions at 4°C – replicating conditions seen in the mud at the bottom of Baffin Bay. “We incubated them for a few weeks to let the microbes do their thing,” says Wasmund. Then they used lab equipment to separate out microbes that had broken down the DNA and incorporated it into their cells. Finally, the researchers used genetic sequencing techniques to identify these DNA-eating microbes and reconstruct their genomes. The team found five different types of bacteria dined on the DNA. Four of the five seemed to be opportunistic DNA consumers, just taking advantage of the molecule because it was available.
2-6-19 Shutdown aside, Joshua trees live an odd life
In the U.S. southwest, Joshua trees evolved a rare, fussy pollination scheme. A year when vandals trashed a Joshua tree in a national park during a U.S. government shutdown is a good time to talk about what’s so unusual about these iconic plants. The trees’ chubby branches ending in rosettes of pointy green leaves add a touch of Dr. Seuss to the Mojave Desert in the U.S. Southwest. Its two species belong to the same family as agave and, believe it or not, asparagus. And the trees bloom with masses of pale flowers erupting from a branch tip. “To me [the flowers] smell kind of like mushrooms or ripe cantaloupe,” says evolutionary ecologist Christopher Irwin Smith of Willamette University in Salem, Ore. His lab has found a form of alcohol in the scent that actually occurs in mushrooms, too. It’s tough to tell how old a Joshua tree is. Their trunks don’t show annual growth rings the way many other trees do. The desert trees became headline news in January when vandals trashed at least one of them at Joshua Tree National Park (SN Online: 1/12/19). What gets biologists really excited about Joshua trees is their pollination, with each of the two tree species relying on its own single species of Tegeticula moth. That could make Joshua tree reproduction highly vulnerable to climate change and other environmental disruptions. Typically, insects pollinate a flower “just by blundering around in there” as they grope for pollen and nectar for food, Smith says. But for the female moths that service the Joshua trees, pollination “does not look like an accident.”
2-6-19 How Earth’s changing ecosystems may have driven human evolution
The most detailed ever look at Earth's prehistoric climate suggests many habitats changed in the past 800,000 years – and this may be why we evolved big brains. FOR the first time, we have had a detailed look at how our climate has changed throughout prehistory, thanks to a surprisingly detailed computer model. And it could shed light on how ecosystem changes shaped our evolution and intelligence. Thanks to ice cores and other natural records, we already knew that, for the past 2.5 million years, Earth has been in an ice age, with permanent ice at both poles. The extent of this ice has often waxed and waned during this time, and we are currently in a warmer, “interglacial” period. But this doesn’t explain why these climate changes happened or how they affected wildlife, says Mark Maslin of University College London, who wasn’t involved in the modelling work. “An ice core in Antarctica just tells you what’s happened in Antarctica,” he says. “Only by using computer models can you actually connect the dots.” Mario Krapp at the University of Cambridge, UK, and his colleagues have now done this, simulating global climate changes over the past 800,000 years. They did it by using models of the past 120,000 years to develop an algorithm, which they then used to reconstruct an outline of the past 800,000 years. This was fleshed out by simulating detailed “snapshots” at intervals throughout the 800,000 years. Running a detailed model for the whole period would have taken too much computer time. The model successfully reconstructed known changes in average global temperature, as well as the different patterns over sea and land. “They seem to be approximating what’s going on extremely well,” says Eleanor Scerri of the Max Planck Institute for the Science of Human History in Jena, Germany.
2-6-19 Cosy up with the Neanderthals, the first humans to make a house a home
Meet the Stone Age people who liked nothing better than spending time indoors around the fire, doing a spot of DIY and having friends over for dinner PUT Matt Pope in a valley apparently untouched by humans and he can tell you where Neanderthals would have built their home. “It’s about a third of the way up a slope, with a really good vista and a solid bit of rock behind,” he says. Anyone who goes camping will recognise these preferences: this is where you want to pitch your tent when you arrive in an unfamiliar place at dusk. It is also where aspirational types dream of buying a place to live. In other words, this is the spot that lures us with siren calls of “home”. There has long been an assumption that the concept of home is as old as humanity. But Pope, an archaeologist at University College London, is challenging that. “We take for granted that early humans had a home, an address, but it wasn’t always with us,” he says. “It’s something we evolved.” The invention of “home”, Pope argues, marked a critical threshold in the long march towards civilisation. As well as being a practical advance, it was also a conceptual leap that shaped the way our ancestors thought and interacted. What’s more, evidence is growing that home wasn’t exclusively the domain of Homo sapiens. In fact, Neanderthals may have been the original homebodies. A picture is emerging of their domestic life that would have been unthinkable just a few years ago. Far from being brutish, they may have enjoyed nothing more than spending time indoors around a cosy fire, doing a spot of DIY and inviting friends over for dinner.
2-6-19 Australia has been home to hopping kangaroos for 20 million years
An ancient group of kangaroo relatives called balbarids had multiple ways of getting around, including hopping, bounding and climbing. The finding may mean we have to rethink how modern day kangaroos came to hop. Kangaroo evolution has been difficult to piece together because there are very few fossils older than one or two million years. The prevailing view of kangaroo evolution is that they began hopping when the climate in Australia became drier and wiped out many forests, but new fossil evidence suggests that their relatives were hopping much earlier. The balbarids were distant cousins of modern kangaroos and lived in forests when the Australian climate was wetter. They went extinct around 10 to 15 million years ago when the climate dried out. One of the most complete skeletons, from a species in the balbarid family called Nambaroo gillespieae, suggests that these animals moved on four legs and did not hop like true kangaroos. Benjamin Kear at Uppsala University, Sweden, and colleagues have now analysed a set of more fragmentary remains, including ankle bones, a calf bone and a claw. They suggest that some balbarids galloped, some hopped, and some climbed in trees. That’s true of modern kangaroos too, if you look beyond the most famous among them. There are rat kangaroos that scurry in the undergrowth and burrow, and tree kangaroos that live in the forests of New Guinea. Short-faced giant kangaroos, which went extinct 30,000 years ago, walked on two legs like us. This versatility has been key to kangaroos’ success, enabling them to exploit a huge range of terrestrial environments, says Kear. The origin of hopping goes all the way back to virtually the beginning of kangaroo evolution, he says.
2-5-19 Scientists studied a ‘haunted house’ to understand why we love horror
Horror films and fairground haunted houses may be enjoyable because they let us overcome simulated threats in a safe space, so we can learn how to cope with negative experiences in real life. To better understand how we experience horror, Mathias Clasen at Aarhus University in Denmark and his colleagues have been studying how people cope with gory surprises. They recruited 280 visitors at a commercial haunted house in Vejle, Denmark, which was set in a dilapidated factory where 30 rooms had been designed to target different fears. For instance, there were dark, claustrophobic spaces and rooms containing actors in zombie make-up. Before they entered the building in groups, each visitor was asked to choose to focus either on minimising or increasing their fear throughout the experience. The team then asked the visitors about the mental tactics they used. Those who tried to maximise their fear said they concentrated on the things meant to frighten them, instead of looking away or thinking about something else. They also told themselves that the situation was really dangerous, and allowed themselves to scream, which Clasen says can make you feel more frightened. Those who tried to lessen their fears did the opposite. But both groups had one response in common: they got closer to others in their group, sometimes holding hands. Clasen says the adrenaline junkies may have done this to experience more fear vicariously through others, while those intent on feeling less fear may have been looking for comfort. “It was striking that the same gesture of seeking physical proximity can work in those diametrically opposed ways,” he says.
2-5-19 The ancestor of all creatures on Earth lived a lukewarm lifestyle
THE ancestor of all life on Earth probably preferred moderate temperatures, not scorching heat as some biologists believe. The finding could shed light on where such early organisms lived, but only if it is confirmed. Everything alive today can be traced back to the last universal common ancestor (LUCA), a single-celled organism that appeared early in Earth’s history. LUCA emerged at least 3.9 billion years ago, and relatively soon after split into two groups called bacteria and archaea, which today make up the majority of all living species. More complex organisms made of multiple cells, like sponges, elephants and us, only appeared billions of years later. Ryan Catchpole and Patrick Forterre of the Pasteur Institute in Paris have re-examined the genetic evidence that LUCA was adapted to extreme heat. They think earlier work may have incorrectly traced a key gene, changing our understanding of LUCA’s habitat. Many biologists have argued that LUCA lived somewhere hot, like a geothermal pond, where temperatures exceed 50°C or even 100°C. They point to the many primitive archaea alive today that are adapted for heat. Organisms that live above 50°C are called thermophiles, while the hardy few that endure 80°C or more are known as hyperthermophiles. LUCA’s genome could provide a clue as to which category it belongs in. Being so ancient, no specimens of this organism remain, but in 2016, a team led by Bill Martin at Heinrich Heine University Düsseldorf in Germany looked for universal genes found in some of the oldest branches of life, which are likely to have been present in LUCA.
2-5-19 Women seem to have younger brains than men the same age
Women have younger brains than men the same age. A study basing age on metabolism rather than birth date found an average 3.8 year difference between men and women. The discovery may help explain why women are more likely than men to stay mentally sharp in their later years. All brains get smaller with age, and it was already known that men’s tend to shrink at a faster rate. To investigate the differences further, Manu Goyal at Washington University School of Medicine in St Louis and colleagues looked at the brains of 205 men and women ranging in age from 20 to 82. They used positron emission tomography, an imaging technique that helps uncover brain metabolism by measuring the flow of oxygen and glucose. The brain consumes large amounts of glucose for energy, but the pattern of use alters with age. They found that metabolic brain ageing correlated with chronological ageing in both men and women, but that at any given age women’s brains were younger, metabolically speaking, than men’s. “It’s not that men’s brains age faster — they start adulthood about three years older than women, and that persists throughout life,” says Goyal. “What we don’t know is what it means. I think this could mean that the reason women don’t experience as much cognitive decline in later years is because their brains are effectively younger, and we’re currently working on a study to confirm that.”
2-5-19 Mouse toes partially regrown after amputation thanks to two proteins
A pair of proteins could help regenerate amputated limbs. When applied to amputated toes, the proteins encouraged both bone and joint growth in mice. Joints are structurally complex, so even for animals that can regrow their lost limbs, rarely can they regenerate their joints as well. Ken Muneoka at Texas A&M University and his colleagues had previously regenerated bones in mice after they were amputated by treating the stump with a bone-growing protein, BMP2. But joint structures never formed. The team suspected that another bone-growing protein, BMP9, could be essential in joint building. So they tried applying the protein to mice that had their toes amputated. After three days, over 60 per cent of the stump bones formed a layer of cartilage, as seen in joints, at the end of the bones. The result was more effective when the team treated the wounds first with BMP2 and then BMP9 a week later. Not only did the bones regrew, they also formed more complete joint structures with part of the new bones attached to them. Although the method does not yet produce a full toe. “Our study is transformational,” says Muneoka. He suggests this experiment proves that even though mammals can’t regenerate body parts, we have cells that know how to and what to grow. “They can do it, they just don’t do it. So, we have to figure out what’s constraining them,” he says. Because human skeletal structure is very similar to that of mouse, Muneoka says he is optimistic that one day we will be able to help amputees regrow their limbs. But more studies need to be done before any trials in humans, he says.
2-4-19 Confused about cancer? Here’s what we really do know about its causes
We are bombarded with stories about things that might give us cancer, yet even the experts don't seem sure. So what's the best way to judge the risks? RED meat, cellphones, plastic drinking bottles, artificial sweeteners, power lines, coffee… Which of these have been linked with cancer? If you are unsure, you aren’t alone. The problem isn’t a lack of information. Rather, we are bombarded with so much information and misinformation about what might cause cancer that it is often hard to separate myth from reality. Yet it is something we must all do, because cancer affects every one of us. Whether or not you have had it yourself, you surely know someone who has. For people in the UK, the lifetime chance of being diagnosed with the disease is 1 in 2. Globally, cancer is second only to cardiovascular disease as a cause of death, killing an estimated 1 in 6 people. Cancer is not a single disease and its causes are many and complex, but there are things we can do to reduce our risk – if only we could identify them. That isn’t easy when even the experts don’t always agree. Nevertheless, our knowledge has come a long way in recent years, thanks to a huge amount of research into both environmental factors and genetic susceptibility. So, what do we know – and don’t know – about the causes of cancer? And, when faced with mixed messages, how can we best judge the risks for ourselves? The extent of public confusion on the subject was glaringly exposed in a survey of 1330 people in England published last year. Researchers from University College London and the University of Leeds, UK, reported that more than a third of the general public mistakenly attributed carcinogenic properties to artificial sweeteners, genetically modified food, drinking from plastic bottles and using a cellphone. Over 40 per cent thought stress causes cancer, although there is no proven link. More worryingly, only 60 per cent of people believed sunburn can lead to cancer. And only 30 per cent were aware of the strong link between human papillomavirus (HPV) infection and the disease.
2-4-19 Teenagers who copy each other’s risk-taking have more friends
From binge-drinking to reckless driving, our teenage years are known to be a time of risk-taking. Now we are starting to understand why such behaviours spread between friends. Many previous studies have shown that adolescents are more likely to start smoking or drinking if their friends do, but it is hard to study how such behaviours spread through social groups. While working at the Dresden University of Technology in Germany, Andrea Reiter and her colleagues used a simple gambling game to dig into the teen appeal of risk-taking, and its social implications. The task involved choosing between a definite payout of €5 or a known, small chance of winning up to €50. The game was played over a series of rounds by 86 male volunteers, half of whom were between 12 and 15, while the rest were adults. When the volunteers played the game alone, the boys were less likely than the men to take the risky gamble of trying for a larger payout. “There is this stereotype, but teens were not more risk-seeking when tested alone,” says Reiter. However, this changed when the participants no longer thought they were alone. In a second run of the experiment, the volunteers met a “partner” face-to-face before playing the game, and were told they could see each other’s actions on a computer. In reality, the researchers were in control of all the “partner’s” decisions. If the fake partner took the risky gamble more often, the boys’ own play became riskier – but only if their partner was another teen, not an adult. The boys’ behaviour changed more than twice as much as that of the adults. A questionnaire revealed that the boys who changed their behaviour the most also reported having more friends and a higher social confidence.
2-4-19 DNA from extinct red wolves lives on in some mysterious Texas coyotes
The find raises questions of whether conservation efforts should preserve DNA, not just species. Mysterious red-coated canids in Texas are stirring debate over how genetic diversity should be preserved. “I thought they were some strange looking coyotes,” wildlife biologist Ron Wooten says of the canids on Galveston Island, where Wooten works. But DNA evidence suggests the large canids might be descendants of red wolves, a species declared in 1980 to be extinct in the wild. A small population of red wolves from a captive breeding program lives in a carefully monitored conservation area in North Carolina. But those wolves have had no contact with other canids, including those in Texas. So maybe, Wooten thought, red wolves never actually went extinct in the wild. He made it his mission to find out. “There was no way I could let this go,” he says. He reached out to evolutionary geneticist Bridgett vonHoldt at Princeton University. She and colleagues have amassed genetic data on about 2,000 North American canids, mostly coyotes and wolves, but with a few dogs thrown into the mix. VonHoldt regularly receives photographs of wolflike animals with requests to identify what species they belong to — an exercise she describes as “really challenging and possibly misleading.” Instead, she asks for tissue samples so that her team can analyze the animal’s DNA. “Many pictures I don’t give a second thought to,” she says. But Wooten’s photos of the Galveston Island canids were “a little bit different.… It just doesn’t look typical of a standard coyote.”
2-4-19 Obesity-related cancers rise for younger US generations, study says
Cancers linked to obesity are rising at a faster rate in millennials than in older generations in the United States, the American Cancer Society has said. It said a steep rise in obesity in the past 40 years may have increased cancer risk in younger generations. And it warned the problem could set back recent progress on cancer. The Society studied millions of health records from 1995 to 2014, publishing its findings in The Lancet Public Health. In the last few decades, there has been mounting evidence that certain cancers can be linked to obesity. Researchers found that the rates of six out of 12 obesity-related cancers (colorectal, uterine, gallbladder, kidney, pancreatic and multiple myeloma - a blood cancer) all went up, particularly in people under the age of 50. And they found steeper rises in successively younger generations aged 25 to 49 - and particularly in millennials, in their 20s and 30s. For example, the risk of colorectal, uterine and gallbladder cancers has doubled for millennials compared to baby boomers, now aged 50 to 70, at the same age. Some of these cancers increased in people over 50 too, but the rises were not as steep. Researchers say this trend may be down to the rapid rise in obesity in the last few decades with "younger generations worldwide experiencing an earlier and longer exposure to the dangers of extra weight".
2-3-19 Why it’s key to identify preschoolers with anxiety and depression
New research shows these kids have mental and physical problems as they grow older. The task was designed to scare the kids. One by one, adults guided children, ranging in age from 3 to 7, into a dimly lit room containing a mysterious covered mound. To build anticipation, the adults intoned, “I have something in here to show you,” or “Let’s be quiet so it doesn’t wake up.” The adult then uncovered the mound — revealed to be a terrarium — and pulled out a realistic looking plastic snake. Throughout the 90-second setup, each child wore a small motion sensor affixed to his or her belt. Those sensors measured the child’s movements, such as when they sped up or twisted around, at 100 times per second. Researchers wanted to see if the movements during a scary situation differed between children diagnosed with depression or anxiety and children without such a diagnosis. It turns out they did. Children with a diagnosis turned further away from the perceived threat — the covered terrarium — than those without a diagnosis. In fact, the sensors could identify very young children who have depression or anxiety about 80 percent of the time, researchers report January 16 in PLOS One. Such a tool could be useful because, even as it’s become widely accepted that children as young as age 3 can suffer from mental health disorders, diagnosis remains difficult. Such children often escape notice because they hold their emotions inside. It’s increasingly clear, though, that these children are at risk of mental and physical health problems later in life, says Lisabeth DiLalla, a developmental psychologist at Southern Illinois University School of Medicine in Carbondale. “The question is: ‘Can we turn that around?’”
2-2-19 Your gut bacteria may match your blood group – but we don’t know why
Gut bacteria seem to vary according to the blood groups of their hosts, but the reason for this is not yet clear. Your ABO blood type is determined by a type of sugar on the surface of your red blood cells. Type A individuals have a different sugar from type B individuals, while AB people have both sugars. O people – who are known as universal donors – have neither. These sugars are called antigens and help tell your immune system that your blood cells belong to you and shouldn’t be attacked. If an A person were to accidentally receive a transfusion of B blood, antibodies made by their immune system would react with the B sugar and flag these cells for destruction. Other parts of the body – including the intestines – carry these antigens too, prompting researchers to wonder if the bacteria that live in our body might as well. To see if our gut bacteria match our blood type, Zhinan Yin at Jinan University in Guangzhou, China, and his colleagues took gut bacteria samples from 149 volunteers from across the four blood groups. The team found that blood type wasn’t linked to any differences in the kinds of bacteria a person had. However, they noticed that bacteria seemed to be recognised by antibodies from different blood types, in a similar way to when antibodies detect incompatible blood cells. This suggests that gut bacteria make sugars that match their host’s blood type. “We were very surprised to see this,” says Yin. While some bacteria are already known to carry molecules that are similar to B antigens, this is the first indirect evidence that bacteria can have sugars that behave like A antigens too.
2-1-19 Washington state in state of emergency
Washington state has declared a state of emergency since an outbreak of the measles virus hit Clark County, with at least 34 cases of the highly infectious and sometimes fatal viral illness. Washington is one of 18 states that permit parents to opt their children out of mandatory measles vaccines for philosophical reasons. In Clark County, 7.9 percent of students got exemptions from vaccination last year.strong>(Webmaster's comment: Some human beings can be so stupid!)
2-1-19 Aspirin and bleeding
Healthy adults should not take a daily low-dose aspirin to prevent heart disease unless a doctor advises them to do so. That’s the conclusion of a major review into previous research, which found that the drug “substantially” raises the chance of dangerous bleeds in the gut and skull. Aspirin’s blood-thinning properties can help prevent heart attacks and strokes for those with existing cardiovascular issues. But for those with no issues, the cons outweigh the pros, the new report says. Its authors analyzed the findings of 13 studies, including three major clinical trials published last year, involving some 164,000 people. Overall, they found that aspirin reduced the risk of cardiovascular problems by 11 percent—but was linked to a 43 percent increase in significant bleeding events. Lead author Sean Lee Zheng, from King’s College London, says doctors need to assess patients’ needs on a case-by-case basis. “Aspirin use requires discussion between the patient and their physician,” he tells The Times (U.K.), “with the knowledge that any small potential cardiovascular benefits are weighed up against the real risk of severe bleeding.”
2-1-19 A blood test for Alzheimer’s
Doctors might soon be able to use a simple blood test to predict if a patient will develop Alzheimer’s more than a decade before the appearance of symptoms. Scientists have previously observed that a raised level of neurofilament light chain (NfL), a protein found in the brain and spinal cord, is a possible indicator of early-stage Alzheimer’s. To explore the issue further, researchers examined NfL levels in 243 people with genetic mutations that predisposed them to the neurodegenerative disease and 162 people without the mutation. They found that just under seven years before Alzheimer’s symptoms developed, the group with the mutation had distinctly higher levels of NfL, reports USA Today. When the team examined how quickly levels of the protein changed over time, they found that the rate of increase was noticeably higher for people with the mutation more than 16 years before symptoms began. Scientists haven’t yet discovered a cure for Alzheimer’s. But an early test could help doctors predict when patients will start showing symptoms and help researchers determine whether potential new treatments are effective. Study author Mathias Jucker, from the German Center for Neurodegenerative Diseases, said that the reason there is no effective treatment for Alzheimer’s “is partly because current therapies start much too late.”
2-1-19 Rhinoceros beetles have weird mouth gears that help them chew
A species of horned beetle has a startling secret: a gearing mechanism in its mouthparts. The beetles beat us to the invention of meshed gears, possibly by millions of years. Japanese rhinoceros beetles (Trypoxylus dichotomus) are found in east Asia. Males can be 8 centimetres long. This is unusually large for an insect, although not as large as male Hercules beetles that can reach double the size. In Japan, the rhinoceros beetles are popular pets and are regularly depicted in anime and other media. “There is nobody who has not touched the horned beetle in Japan,” says Hiroaki Abe at the Tokyo University of Agriculture and Technology in Japan. Abe’s team was studying the beetles’ genetics when their breeding programme created some with abnormally-shaped heads. To figure out exactly what was unusual, they needed to know what the mouthparts or “mandibles” of normal beetles looked like. Surprisingly, this had never been documented. So Abe’s colleague Wataru Ichiishi ?dissected some and was startled to discover that the right and left mandibles moved simultaneously. A closer examination revealed that each mandible has two gear teeth, and the two sets mesh. As a result, when one mandible moves, so does the other. Abe thinks the gearing has evolved because of the beetles’ lifestyle. They spend a lot of time chewing the tough bark of trees to feed on sap. If one of the mandibles broke, the beetle might starve. Linking the two mandibles with gears spreads the force between them, reducing the strain on each mandible and making it less likely to break.