Boeing Milestones of Flight Hall
Now open
After two years of renovations, some of the museum’s most cherished artifacts — including the Spirit of St. Louis and an Apollo Lunar Module — are now on display alongside new objects, including a studio model of the Starship Enterprise.

National Air & Space Museum, Washington, D.C.
Pterosaurs: Flight in the Age of Dinosaurs
Through October 2
Fossils, life-size models and a virtual flight lab transport visitors back to the time of these ancient fliers.

Natural History Museum of Los Angeles County
DARPA: Redefining Possible
Through September 5
In this hands-on exhibit, see a humanlike robot, prosthetic arm, robotic exoskeleton and other high-tech innovations developed by the U.S. Defense Advanced Research Projects Agency over the last six decades.

Museum of Science and Industry, Chicago

Exercise may not erase old memories, as some studies in animals have previously suggested.

Running on an exercise wheel doesn’t make rats forget previous trips through an underwater maze, Ashok Shetty and colleagues report August 2 in the Journal of Neuroscience. Exercise or not, four weeks after learning how to find a hidden platform, rats seem to remember the location just fine, the team found.

The results conflict with two earlier papers that show that running triggers memory loss in some rodents by boosting the birth of new brain cells. Making new brain cells rejiggers memory circuits, and that can make it hard for animals to remember what they’ve learned, says Paul Frankland, a neuroscientist at the Hospital for Sick Children in Toronto. He has reported this phenomenon in mice, guinea pigs and degus (SN: 6/14/14, p. 7).
Maybe rats are the exception, he says, “but I’m not convinced.”

In 2014, Frankland and colleagues reported that brain cell genesis clears out fearful memories in three different kinds of rodents. Two years later, Frankland’s team found similar results with spatial memories. After exercising, mice had trouble remembering the location of a hidden platform in a water maze, the team reported in February in Nature Communications. Again, Frankland and colleagues pinned the memory wipeout on brain cell creation — like a chalkboard eraser that brushes away old information. The wipe seemed to clear the way for new memories to form.

Shetty, a neuroscientist at Texas A&M Health Science Center in Temple, wondered if the results held true in rats, too. “Rats are quite different from mice,” he says. “Their biology is similar to humans.”
Using a water maze similar to Frankland’s, Shetty’s team taught two groups of rats how to find a hidden platform in eight training sessions over eight days. Then rats in just one of the groups exercised on a running wheel. Four weeks later, rats in both groups performed the same in the maze test — despite the fact that running rats had 1.5 to 2 times more newly born brain cells in the hippocampus, a skinny strip of tissue that’s thought to help form new memories.
These results and other memory tests “clearly showed that exercise did not interfere with memory recall,” Shetty says. And it’s likely that exercise doesn’t harm human memories either, he says.

Frankland says it’s possible that Shetty’s rats just learned the water maze too well. Shetty’s team trained their rodents for longer than Frankland’s team did, perhaps etching memories more deeply in the brain.

“The stronger the memory is, the harder it is going to be to erase it,” Frankland says.

But he points out that erasing memories isn’t necessarily a bad thing. “People get hung up on this idea,” he says, but actually, clearing out old info from the brain — forgetting — is important. Without some sort of clearance process, “your memory is going to be full of junk.”

Manchester, England, is not the birthplace of graphene — the atom-thin, honeycomb-like layer of carbon known for its wondrous properties and seemingly limitless applications. But the city is the material’s main booster and, according to the University of Manchester, the official Home of Graphene. That’s because it was there that Andre Geim and Kostya Novoselov figured out that you could isolate the elusive material from graphite (the “lead” in pencils) with repeated dabs of sticky tape.
The two-dimensional material also proved to be a peerless electrical conductor and superstrong, earning the two Manchester scientists the 2010 Nobel Prize in physics. So when the city played host to the EuroScience Open Forum conference late last month, it made sense that Geim, graphene and the material’s many evolving applications took center stage. At the local science museum’s new exhibit about graphene, I learned that Geim is the only Nobelist who has also been honored with an Ig Nobel (which has fun celebrating seemingly useless research in science). He contends many are more familiar with his Ig Nobel–winning device to levitate a tiny frog than with his work on graphene.

Notably, graphene comes up in both of the feature stories in this issue, adding some heft, perhaps, to Mancunian claims. In Thomas Sumner’s cover story “Quenching society’s thirst,” about the growing interest in desalination to meet the globe’s escalating need for freshwater, graphene oxide has a potentially starring role. New membranes made from this material may help increase the efficiency of separating salt from water. Cost and efficiency, Sumner reports, remain the biggest obstacles to the widespread use of desalination.

Graphene can serve as analogy and inspiration in physicists’ efforts to create solid metallic hydrogen, another theorized wonder material, which Emily Conover describes in “Chasing a devious metal.” “It’s a high-stakes, high-passion pursuit that sparks dreams of a coveted new material that could unlock enormous technological advances in electronics,” Conover writes. Solid hydrogen, which has been made, takes on a graphenelike structure when squeezed to high pressures. Solid metal hydrogen might be a superconductor at room temperature, an exciting prospect. Despite significant progress, so far no one has been able to create it.

Local celebrity or not, graphene did share the spotlight with other science superstars at the EuroScience meeting. The gene-editing tool CRISPR got lots of attention. In a review of the historic detection of gravitational waves, Sheila Rowan of the University of Glasgow offered a bevy of questions that gravitational astronomy might be able to answer in the coming years: Where and when do black holes form? What does that tell you about the large-scale formation of galaxies? Is general relativity still valid when gravity is very strong (such as near supermassive black holes)? A session on the human microbiome generated even more questions, as scientists described efforts to use microbial species as telltale signs of diseases such as cancer. And a debate about how to prevent food allergies left most agreeing that more data are needed. As answers come in on all of these and many more fascinating topics, you can be sure that Science News will be there to report on them.

Going for walks, playing fetch and now participating in genetic research are just a few things people and their dogs can do together.

Darwin’s Dogs, a citizen science project headquartered at the University of Massachusetts Medical School in Worcester, is looking for good — and bad — dogs to donate DNA. The project aims to uncover genes that govern behavior, including those involved in mental illness in both people and pets.

Looking to dogs for clues about mental illness isn’t as strange as it may seem. Certain breeds are plagued by some of the same diseases and mental health issues that afflict people. Researchers have learned about the genetics of narcolepsy and obsessive compulsive disorder, as well as cancer, blindness and many other ailments from studying purebred dogs. Studies of purebreds are mainly useful when the problem is caused by mutations in a single gene. But most behaviors are the product of interactions between many genes and the environment. A search for those genes can’t be done with a small number of genetically similar dogs. So, Darwin’s Dogs hopes to gather data on a large number of canines, including many breeds and genetically diverse mutts.
Finding behavior-related genes, such as ones that lead dogs to chew up shoes or engage in marathon fetch sessions, may give clues to genes that affect human behavior. “It seemed to me that if we could understand how [changes in DNA] make a dog so excited about chasing a ball, we could learn something about how our brains work and what goes wrong in psychiatric disease,” says project leader Elinor Karlsson.

Karlsson and colleagues launched darwinsdogs.org, inviting people to answer questions about their dogs’ behavior and share their pets’ DNA. More than 7,000 dog owners have already signed up, and the researchers are still recruiting new volunteers.

The process is simple and can be done alone with your dog, or even as a family activity. First, take an online quiz about your canine companion. The quiz is divided into multiple sections. Some sections gather basic information about your dog’s appearance, exercise and eating habits; others ask about simple behaviors, such as whether your dog crosses its front paws when lying down or tilts its head. (Some questions are philosophical puzzles like whether your dog knows it is a dog.) Each question has a comment box in case you want to explain an answer. Plan to spend at least half an hour completing the questionnaire.

Once the questions are answered and the dog is registered, researchers send you a DNA sampling kit that comes with written instructions and an easy-to-follow picture guide. The kit contains a large sterile cotton swab for collecting DNA from your dog’s mouth. (It’s an easy procedure for the human involved, and Sally, the 14-year-old Irish setter “volunteer” Science News sampled, was rather stoic.) Also included is a tape measure for recording your dog’s height, length, nose and collar size. When you’re done, just seal the sample, measurement sheet and consent form inside the return mailer and drop it in a mailbox.

Dog owners don’t need to pay a fee to participate, but they do need patience, Karlsson says. It takes time to analyze DNA, and the researchers can’t say exactly how long it will be before owners (and Science News) learn their dogs’ results. These results will include the dog’s raw genetic data as well as information about the dog’s possible ancestry. Knowing ancestry or particular mutations a dog carries may help veterinarians personalize a dog’s care.
Dog trainers are being enlisted to give owners feedback on their dogs’ personalities and to suggest activities the dogs may enjoy. Karlsson hopes to create a way for impatient owners who are willing to donate money to the project to get their reports back faster.

As of today, antibacterial soaps have a short shelf life. The U.S. Food and Drug Administration has banned soap products containing 19 active ingredients, including the notorious chemical triclosan, marketed as antiseptics.

While the term “antibacterial” suggests to consumers that such soaps prevent the spread of germs, evidence suggests otherwise. After asking companies to submit data on the safety and efficacy of their products back in 2013, the FDA noted in its September 2 final ruling that manufacturers failed to prove that these products were safe to use every day or that they were more effective than plain old soap and water at cutting infectious microbes.

“In fact, some data suggests that antibacterial ingredients may do more harm than good over the long-term,” Janet Woodcock, director of the FDA’s Center for Drug Evaluation and Research, said in a statement.

Triclosan, in particular, has a pretty bad rap. Found in many household products, the chemical ends up everywhere from vegetables to our snot. It’s been associated with exposure to toxic compounds, risk of staph infections and mucking up sewage treatment. Over a decade of damning data had already prompted some companies to remove triclosan from their products. Others will have a year to remove it and other newly banned ingredients from their recipes.

The FDA ban does not include antibacterial hand sanitizers, which the agency is evaluating separately. In the meantime, the FDA recommends using hand sanitizers that are at least 60 percent alcohol, or washing with old-school soap and water.

Live long and prosper
In Science News’ special report on a­ging (SN: 7/23/16, p. 16), writers Laura Sanders, Tina Hesman Saey and Susan Milius explored the latest research — from the evolution of aging in the animal kingdom to scientists’ quest to delay the process in humans’ bodies and minds.

“I would very much like to know how research into aging may benefit people who are middle-aged or elderly now?” asked leftysrule200 in a Reddit Ask Me Anything about the special report. “Is there any research that can result in treatments in the very near future, or are the real-world applications only going to be visible in the distant future?”
Middle-aged and elderly people will be the first to benefit from aging research, Saey says. “A clinical trial using the diabetes drug metformin as an antiaging therapy will begin soon. That drug will be tested on healthy people aged 60 and older,” she says.

Sanders cautions that most antiaging treatments are still a long way off. But various studies in rodents and humans provide potential clues to aging’s secrets. Blood from young rats, for instance, has been shown to rejuvenate the bodies and brains of old rats. Based on those findings, a clinical study in humans is now under way that is looking at the effects of plasma from young donors on the brains of people with Alzheimer’s. “If scientists could pinpoint the compounds that give young blood its power, then they could presumably develop drugs that mimic that process,” Sanders says.
In the meantime, people may be able to slow the effects of aging by leading a healthy lifestyle. Sanders points to a long-term study of middle-aged women in Australia. Women who were more physically active had sharper memories 20 years later, the researchers found. Until proven antiaging treatments are available, “it seems that keeping the body physically active and strong is one of the best ways to keep your brain sharp as you age,” she says.
Dino spills its guts
Tiny tracks discovered in the blackened stomach contents of a 77-million-year-old duck-billed dinosaur fossil suggest gut parasites infected dinosaurs, Meghan Rosen reported in “Parasites wormed way into dino’s gut” (SN: 7/23/16, p. 14).

Online reader Jim Stangle Dvm thought the worms may not have been parasites at all. “It is more likely that the tunnels were formed by a scavenger worm [after the dino had died]. Still I think the findings are way cool!” he wrote.

It’s hard to say definitively whether the burrows were made by parasites or not, says paleontologist Justin Tweet. Scavenger worms could have tunneled through the gut after the dino’s death, but his team found only one type of worm burrow “which suggests that either only one kind of scavenger had access to the carcass,” or “that these burrows were an inside job,” Tweet says.

That’s no moon!
A recently discovered asteroid appears to orbit Earth, but that’s just an illusion. The asteroid orbits the sun, but its constant proximity to Earth makes it the planet’s only known quasisatellite, Christopher Crockett reported in “Say What? Quasi­satellite” (SN: 7/23/16, p. 5).

Reader Mike Lieber wondered if the moon could also be a quasisatellite. “The gravitational attraction of the sun on the moon is twice that of the Earth,” he wrote. “It seems that the apparent looping of the moon around the Earth is also illusory.”

The moon is a true satellite, Crockett says. If the sun were to dis­appear, the moon would continue orbiting Earth. “The moon is within Earth’s ‘Hill sphere,’ the volume of space in which Earth’s gravity is the dominant influence,” he says. “The strength of the gravitational force isn’t as important as by how much it changes from one place to another.” Given the moon’s proximity to our planet, Earth prevails. “The moon orbits Earth and the Earth-moon s­ystem orbits the sun,” he says.

For some dropped foods, the five-second rule is about five seconds too long. Wet foods, such as watermelon, slurp up floor germs almost immediately, scientists report online September 2 in Applied and Environmental Microbiology.

Robyn Miranda and Donald Schaffner of Rutgers University in New Brunswick, N.J., tested gummy candy, watermelon and buttered and unbuttered bread by dropping morsels onto various surfaces coated with Enterobacter aerogenes bacteria. Food was left on each surface — stainless steel, ceramic tile, wood and carpet — for time periods ranging from less than a second to five minutes. Afterward, the researchers measured the amount of E. aerogenes on the food, harmless bacteria that share attachment characteristics with stomach-turning Salmonella.

As expected, longer contact times generally meant more bacteria on the food. But the transfer depended on other factors, too. Carpet, for instance, was less likely to transfer germs than the other surfaces. Gummy candies, particularly those on carpet, stayed relatively clean. But juicy watermelon quickly picked up lots of bacteria from all surfaces in less than a second. These complexities, the authors write, mean that the five-second rule is probably a rule worth dropping.

Shock waves may have jolted the infant cosmos. Clumpiness in the density of the early universe piled up into traveling waves of abrupt density spikes, or shocks, like those that create a sonic boom, scientists say.

Although a subtle effect, the shock waves could help scientists explain how matter came to dominate antimatter in the universe. They also could reveal the origins of the magnetic fields that pervade the cosmos. One day, traces of these shocks, in the form of gravitational waves, may even be detectable.
Scientists believe that the early universe was lumpy — with some parts denser than others. These density ripples, known as perturbations, serve as the seeds of stars and galaxies. Now, scientists have added a new wrinkle to this picture. As the ripples rapidly evolved they became steeper, like waves swelling near the shore, until eventually creating shocks analogous to a breaking wave. As a shock passes through a region of the universe, the density changes abruptly, before settling back down to a more typical, slowly varying density. “Under the simplest and most conservative assumptions about the nature of the universe coming out of the Big Bang, these shocks would inevitably form,” says cosmologist Neil Turok of the Perimeter Institute for Theoretical Physics in Waterloo, Canada.

In a paper published September 21 in Physical Review Letters, Turok and Ue-Li Pen of the Canadian Institute for Theoretical Astrophysics in Toronto performed calculations and simulations that indicate shocks would form less than one ten-thousandth of a second after the Big Bang.

“It’s interesting that nobody’s actually noticed that before,” says cosmologist Kevork Abazajian of the University of California, Irvine. “It’s an important effect if it actually happened.”

These shocks, Turok and Pen found, could produce magnetic fields, potentially pointing to an answer to a cosmological puzzle. Magnetic fields permeate the Milky Way and other parts of the cosmos, but scientists don’t know whether they sprang up just after the birth of the universe or much later, after galaxies had formed. Shock waves could explain how fields might have formed early on. When two shocks collide, they create a swirling motion, sending electrically charged particles spiraling in a way that could generate magnetic fields.
Shocks could also play a role in explaining why the universe is made predominantly of matter. The Big Bang should have yielded equal amounts of matter and antimatter; how the cosmic scales were tipped in matter’s favor is still unexplained. Certain theorized processes could favor the production of matter, but it’s thought they could happen only if temperatures in the universe are uneven. Shocks would create abrupt temperature jumps that would allow such processes to occur.

Scientists may be able to verify these calculations by detecting the gravitational waves that would have been produced when shocks collided. Unfortunately, the gravitational ripples produced would likely be too small to detect with current technologies. But under certain theories, in which large density fluctuations create regions so dense that they would collapse into black holes, the gravitational waves from shocks would be detectable in the near future. “If there was anything peculiar in the early universe, you would actually be able to detect this with upcoming technology,” says Abazajian. “I think that is remarkable.”

When the body’s internal sense of time doesn’t match up with outside cues, people can suffer, and not just from a lack of sleep.

Such ailments are similar in a way to motion sickness — the queasiness caused when body sensations of movement don’t match the external world. So scientists propose calling time-related troubles, which can afflict time-zone hoppers and people who work at night, “circadian-time sickness.” This malady can be described, these scientists say, with a certain type of math.
The idea, to be published in Trends in Neurosciences, is “intriguing and thought-provoking,” says neuroscientist Samer Hattar of Johns Hopkins University. “They really came up with an interesting idea of how to explain the mismatch.”

Neuroscientist Raymond van Ee of Radboud University in the Netherlands and colleagues knew that many studies had turned up ill effects from an out-of-whack circadian clock. Depression, metabolic syndromes and memory troubles have been found alongside altered daily rhythms. But despite these results, scientists don’t have a good understanding of how body clocks work, van Ee says.

Van Ee and colleagues offer a new perspective by using a type of math called Bayesian inference to describe the circadian trouble. Bayesian inference can be used to describe how the brain makes and refines predictions about the world. This guesswork relies on the combination of previous knowledge and incoming sensory information (SN: 5/28/16, p. 18). In the case of circadian-time sickness, these two cues don’t match up, the researchers propose.

Some pacemaking nerve cells respond directly to light, allowing them to track the outside environment. Other pacemakers don’t respond to light but rely on internal signals instead. Working together, these two groups of nerve cells, without any supervision from a master clock, can set the body’s rhythms. But when the two timekeepers arrive at different conclusions, the conflict muddies the time readout in the body, leading to a confused state that could cause poor health outcomes, van Ee and colleagues argue.

This description of circadian-time sickness is notable for something it leaves out — sleep. While it’s true that shifted sleep cycles can cause trouble, a misalignment between internal and external signals may cause problems even when sleep is unaffected, the researchers suggest. That runs counter to the simple and appealing idea that out-of-sync rhythms cause sleep deprivation, which in turn affects the body and brain. That idea “was totally linear and beautiful,” Hattar says. “But once you start looking very carefully at the data in the field, you find inconsistencies that people ignored.”
It’s difficult to disentangle sleep from circadian misalignments, says neuroscientist Ilia Karatsoreos of Washington State University in Pullman. Still, research by him and others has turned up detrimental effects from misaligned circadian rhythms — even when sleep was normal. This new paper helps highlight why “it is important to be able to study and understand the contribution of each,” he says.

The concept of circadian-time sickness is an idea that awaits testing, Karatsoreos cautions. Yet it’s a “useful way for us to talk about this general problem, if only for the fact that it’s a way of thinking that I’ve really never seen before.”

Heating small patches of forest shows how climate warming might change the winner-loser dynamics as species struggle for control of prize territories. And such shifts in control could have wide-ranging effects on ecosystems.

The species are cavity-nesting ants in eastern North America. Normally, communities of these ant species go through frequent turnovers in control of nest sites. But as researchers heated enclosures to mimic increasingly severe climate warming, the control started shifting toward a few persistent winners. Several heat-loving species tended to stay in nests unusually long, instead of being replaced in faster ant upheavals, says Sarah Diamond of Case Western Reserve University in Cleveland.
That’s worrisome not only for the new perpetual losers among ants but for the ecosystem as a whole, she and her colleagues argue October 26 in Science Advances. Ants have an outsized effect on ecosystems. They churn up soil, shape the flow of nutrients and disperse seeds to new homes. Ant species that can’t compete in a warmer climate may blink out of the community array, with consequences for other species they affect.

Teasing out the indirect effects of climate change has been difficult. “We’ve all sort of thrown up our hands and said probably these interactions are quite important, but they’re really hard to measure so we’re just going to ignore that for now,” Diamond says.
Experiments have begun tackling those interactions, and the ant enclosures were among the most ambitious. At each of two experimental sites — in North Carolina and Massachusetts — researchers set up 15 roomy plots to mimic various warming scenarios, from 1.5 degrees Celsius above the surrounding air temperature to an extra 5.5 degrees C. To install outdoor heating, “we had backhoes in there digging trenches,” Diamond says. Giant propane tanks fueled boilers that forced warmer air into the enclosures to heat the soil. Computers monitored soil temperature and fine-tuned air flow.
At least 60 species of local ants came and went naturally, some of them nesting in boxes the researchers placed in the enclosures. For five years, the researchers regularly monitored which common species were living in the boxes.
Warmth gave an edge to a few heat-tolerant species such as Temnothorax longispinosus in the forest in Massachusetts. This tiny ant can build colonies inside an acorn and is a known target for attacks by slavemaker ants that invade nests instead of establishing their own. With increased warming, however, it and a few other heat-loving ants tended to hold their nests longer.

Those longer stints destabilize the ant community with its usual faster pace of turnovers of nests, which typically gives more species a chance at decent shelter and better luck in surviving in the community. What’s more, the analysis showed that the more a plot was heated, the more time the ants would need after some disturbance to return to the equilibrium of their usual affairs.

“A key strength of this study is their regular sampling,” says Jason Tylianakis, who holds joint appointments at the University of Canterbury in New Zealand and Imperial College London. Those data gave the scientists an unusually detailed picture of subtle community effects, he says.

The authors have “documented a new consequence of temperature change on communities,” says marine ecologist Sarah Gilman of the Claremont Colleges in California. Other studies have talked about climate change pushing communities to dramatically new, but ultimately stable states. But the ant experiment shows that climate change may be undermining the stability of communities that, at least for the moment, still look fairly normal.