Some flu strains can make mice forgetful

With fevers, chills and aches, the flu can pound the body. Some influenza viruses may hammer the brain, too. Months after being infected with influenza, mice had signs of brain damage and memory trouble, researchers report online February 26 in the Journal of Neuroscience.

It’s unclear if people’s memories are affected in the same way as those of mice. But the new research adds to evidence suggesting that some body-wracking infections could also harm the human brain, says epidemiologist and neurologist Mitchell Elkind of Columbia University, who was not involved in the study.
Obvious to anyone who has been waylaid by the flu, brainpower can suffer at the infection’s peak. But not much is known about any potential lingering effects on thinking or memory. “It hasn’t occurred to people that it might be something to test,” says neurobiologist Martin Korte of Technische Universität Braunschweig in Germany.

The new study examined the effects of three types of influenza A — H1N1, the strain behind 2009’s swine flu outbreak; H7N7, a dangerous strain that only rarely infects people; and H3N2, the strain behind much of the 2017–2018 flu season misery (SN: 2/17/18, p. 12). Korte and colleagues shot these viruses into mice’s noses, and then looked for memory problems 30, 60 and 120 days later.

A month after infection, the mice all appeared to have recovered and gained back weight. But those that had received H3N2 and H7N7 had trouble remembering the location of a hidden platform in a pool of water, the researchers found. Mice that received no influenza or the milder H1N1 virus performed normally at the task.
Researchers also studied the brain tissue of the infected mice under a microscope and found that the memory problems tracked with changes in nerve cells. A month after H7N7 or H3N2 infection, mice had fewer nerve cell connectors called dendritic spines on cells in the hippocampus, a brain region involved in memory. Electrical experiments on the nerve cell samples in dishes also suggested the cells’ signal-sending abilities were impaired.
What’s more, these mice’s brains looked inflamed under the microscope, full of immune cells called microglia that were still revved up 30 and 60 days after infection. Cell counts revealed that mice that had suffered through H3N2 or H7N7 had more active microglia than mice infected with H1N1 or no virus at all. That lingering activity was surprising, Korte says; most immune cells in the body usually settle down soon after an infection clears.

These memory problems and signs of brain trouble were gone by 120 days, which translates to about a decade in human time, Korte says. “I’m not saying that everyone who has influenza is cognitively impaired for 10 years,” he says, noting that human brains are much more complex than those of mice. “The news is more that we should not only look at lung functionality after the flu, but also cognitive effects, weeks and months after infection.”

H7N7 can infect brain cells directly. But H1N1 and H3N2 don’t typically get into the brain (and Korte and colleagues confirmed that in their experiments). Some flu viruses may be causing brain trouble remotely, perhaps through inflammatory signals in the blood making their way into the brain, the study suggests. If that pathway is confirmed, then many types of infections could cause similar effects on the brain. “It is plausible that this is a general phenomenon,” Elkind says.

Massive stellar flare may have fried Earth’s nearest exoplanet

Proxima Centauri has a temper. Earth’s nearest planet-hosting neighbor released a gigantic flare in March 2017, a new analysis of observations of the star shows. And that’s bad news for the potential for life on the star’s planet, Proxima b.

The star got 1,000 times brighter over 10 seconds before dimming again. That can best be explained by an enormous stellar flare, astronomer Meredith MacGregor of the Carnegie Institution for Science in Washington, D.C., and colleagues report February 26 in Astrophysical Journal Letters.
Because Proxima b is so much closer to its star than Earth is to the sun, the flare would have blasted Proxima b with 4,000 times more radiation than Earth typically gets from the sun’s flares. “If there are flares like this at all frequently, then [the exoplanet] is likely not in the best shape,” MacGregor says.

Proxima b was one of the most sought-after sites for finding life outside the solar system. Just four light-years away, it has a mass about the same as Earth’s and probably has temperatures suitable for liquid water (SN: 12/24/16, p. 20). But its star is an M dwarf, a class of small dim stars notoriously prone to flares that could rip away their planets’ atmospheres (SN: 6/24/17, p. 18).
MacGregor and her colleagues reanalyzed data from a recent study led by astronomer Guillem Anglada of the Institute of Astrophysics of Andalusia in Granada, Spain. Anglada and his colleagues had observed Proxima Centauri with the Atacama Large Millimeter Array telescopes in Chile. The team saw extra light that it interpreted as a ring of dust analogous to the solar system’s Kuiper Belt, scattering the light in all directions, the team reported November 15 in Astrophysical Journal Letters.
But Anglada and his colleagues had averaged the amount of light over 10 hours of observations. That smeared out any short-term changes in the star’s brightness — such as a bright flare.

When MacGregor’s team reanalyzed the data, they found that all the excess light came from the same two-minute period on March 24. A massive flare explains all the extra light, she says — none of it was masquerading as a glittering dust ring.

Anglada says he and his colleagues are aware of the March 24 flare and are currently revising their original claim. But he says the flare can’t account for all the extra light, so the dust ring theory might still survive.

Renowned physicist Stephen Hawking dies at 76

Physicist Stephen Hawking, a black hole whisperer who divined secrets of the universe’s most inscrutable objects, died March 14 at age 76. In addition to his scientific research, Hawking, a professor at the University of Cambridge, was known for his popular science books, including the best-selling A Brief History of Time, which captivated readers with lucid explanations of the universe’s birth and the physical laws that rule the cosmos.

In one of his best-known discoveries, Hawking determined that black holes are not truly black. Instead, they emit a faint haze of particles, known as Hawking radiation (SN: 5/31/14, p. 16). This discovery, which arose at the interface of gravity and quantum mechanics, had remarkable consequences. It suggested that black holes are not eternal, but eventually evaporate. That led to a conundrum known as the black hole information paradox (SN: 10/3/15, p. 10): When a black hole disappears, what happens to the information that fell into it? Physicists are still puzzling over that question.

In the face of physical disabilities due to amyotrophic lateral sclerosis, which profoundly limited his mobility and ability to communicate, Hawking became one of science’s most well-known figures, and survived far beyond the timeline initially expected given his condition.

Science News has covered Hawking’s work extensively over the past decades, including his four laws of black hole mechanics, his work on miniature black holes and, most recently, Hawking’s search for a solution to the black hole paradox.

How oral vaccines could save Ethiopian wolves from extinction

Deep in the Bale Mountains of Ethiopia, wildlife workers trek up above 9,800 feet to save some of the world’s most rare carnivores, Ethiopian wolves.

“It’s cold, tough work,” says Eric Bedin, who leads the field monitoring team in its uphill battle.

In this sparse, sometimes snowy landscape, the lanky and ginger-colored wolves (Canis simensis) reign as the region’s apex predators. Yet the combined threats of rabies, canine distemper and habitat reduction have the animals cornered.

Bedin and his colleagues, traveling by horse and on foot through dramatically shifting temperatures and weather, track these solitary hunters for weeks at a time. Team members know every wolf in most packs in these mountains. The team has vaccinated some wolves against rabies, only to have hopes dashed when the animals died of distemper months later.
“These guys work their asses off to protect these wolves,” says Claudio Sillero, a conservation biologist at the University of Oxford who heads up the Ethiopian Wolf Conservation Programme, of which the field monitoring team is an integral part. Down the line, humans stand to benefit from all this work too.

Sillero and his colleagues have been at this for 30 years. They’ve seen four major outbreaks of rabies alone, each leaving dozens of carcasses across the highlands and cutting some populations by as much as 75 percent.

Today, fewer than 500 Ethiopian wolves exist — around half of them in the Bale Mountains. A new oral rabies vaccine program aims to give the endangered animals a fighting chance. It may be their best hope for survival, Sillero says.

Later this year, if all goes well, oral vaccines hidden in hunks of goat meat will be scattered across wolf ranges and eaten by the animals. One dose every two years should bolster immunity against rabies among these iconic animals immortalized on several of their country’s postage stamps.
One Health
Vaccinating endangered animals en masse in the wild is rarely attempted. Making the case for vaccination takes years of testing. And even when the case is strong for stepping in, the tools needed to vaccinate wildlife aren’t often available, says Tonie Rocke, an epizootiologist with the U.S. Geological Survey in Madison, Wis. On the opposite side of the globe from Bale, on North America’s Great Plains, Rocke’s lab is testing an oral vaccine to protect prairie dogs and endangered ferrets from plague.
A recent synergy has made these new oral vaccine efforts possible: improvements in vaccine technology (developed for humans and domesticated animals) and growing public and scientific interest in “One Health.” The conservation buzzword refers to efforts to help one species that also benefit others, including humans.

The researchers pushing for a green light in Ethiopia point to the one shining success in oral vaccines for wild animals, and to its One Health benefits. From 1978 to 2010, oral vaccines sprinkled across parts of Europe eliminated rabies in red foxes. Europe’s rabies cases in humans and other animals dropped by 80 percent from 1984 to 2014. But rabies is still common in certain parts of the world, including Ethiopia. Worldwide, more than 59,000 people die from the disease each year.

Successes on the plateaus of Bale and the prairies of North America could open the door for other vaccines to protect threatened species. Vaccines against Ebola in great apes and white-nose syndrome in bats are in the works.

But introducing vaccines into natural environments is a hard sell and can come with controversy and unexpected consequences.
A last resort
To the average U.S. vet or dog owner, vaccination is a no-brainer. But for endangered species, the stakes are high. Some conservationists are reluctant to intervene with disease-preventing vaccines in the wild, says Karen Laurenson, an epidemiologist and veterinarian with the Frankfurt Zoological Society.

Disease has its place in ecosystems. It can control population levels and put pressure on species to develop natural resistance, says Laurenson, who started working with the wolf project in the mid-1990s. Using a vaccine to take a disease out of the mix could leave a population vulnerable to future outbreaks should the vaccine become ineffective or stop being used. In an ecosystem with multiple power players, one vaccinated predator could gain an unnatural advantage over its competitors.

Some vaccines also bring direct risks. Injectable vaccines often require trapping the animal — a costly endeavor that’s stressful and dangerous for both wild animals and the humans doing the vaccinating. Oral vaccines could be scooped up and eaten by other animals. Plus, for an oral or injectable attenuated vaccine, which contains a living but harmless version of a virus, there’s a slim possibility that evolutionary pressure could eventually drive the virus, now distributed through the population, to become lethal again.

Because room for error is slim for a species on the brink of extinction, most instances of vaccine use have been limited to emergency responses during ongoing outbreaks.

Projects that don’t go well can have lasting repercussions. In 1990, researchers tried to vaccinate some packs of endangered African wild dogs (Lycaon pictus) in Tanzania and Kenya against rabies, assuming the disease was behind a recent dip in numbers. Every dog in the study died. The stress of getting vaccinated, shot by dart from a distance, may have made the dogs more susceptible to disease, though that theory was never proven. The incident increased skepticism about vaccines and caused some African countries to tighten vaccine regulations. “It left a terrible legacy,” says veterinarian Richard Kock of the University of London.

The long game
The uphill battle faced by Sillero’s team involves more than the challenges of canvassing the Ethiopian highlands. Making a case to government officials that oral vaccines are necessary conservation tools took decades of fieldwork, genetic testing and meetings upon meetings. “The credit really goes to Claudio and the others for persisting,” Laurenson says. “Even when the doors have been shut, sometimes they’ve kept banging.”

Sillero arrived in Ethiopia in 1987 to study the wolves. A rabies outbreak hit in late 1989. Just as it does in dogs and humans, the disease attacks a wolf’s brain, causing aggressive behavior and, eventually, death. Canine distemper appeared in 1992. Marked by severe diarrhea, vomiting and coughing, the disease appears to hit wolves harder than dogs, Sillero says. The Ethiopian packs have faced four more major flare-ups of rabies and two of distemper. Two of the eight populations of wolves he came to study have gone extinct in that time.

“This is a human-caused problem, not a natural dynamic,” Laurenson says. Each year, shepherds and farmers move higher up into the wolves’ habitat, bringing grazing livestock. These people also bring domesticated dogs — the primary carriers of rabies and canine distemper (SN Online: 9/30/16). In one area of Ethiopia, wolf habitat shrunk by 34 percent from 1985 to 2003. Islands of wolf populations persist in remote highland areas surrounded by oceans of free-ranging dogs.

Vaccinating the wolves was plan B, after the lower-risk approach of vaccinating domestic dogs didn’t cut it. Because the dogs roam far and wide, dog vaccination programs didn’t reach enough animals to generate prolonged protection and prevent outbreaks in wolves. “I’m sure we were improving the situation and reducing the chance of spillovers in wild carnivores, but we weren’t preventing them altogether,” Sillero says.

Going with oral vaccines was plan C. In 2003, the government approved use of an injectable vaccine only in response to outbreaks. Sillero’s team first had to collect samples and send them to international labs to confirm that an outbreak was happening. The researchers were always behind. An oral option that proactively protects the animals started to sound like a smart way to go.

Deliver the dose
On paper, the wolves look like good candidates for an oral vaccine intervention. Few other animals brave the highlands habitat, so the odds are low that a vaccine distributed in bait would get eaten by the wrong creatures. And not vaccinating is arguably riskier than making the effort. Consecutive rabies and distemper outbreaks recently cut one of the smallest known wolf populations down to two individuals, Sillero’s team reported in December in Emerging Infectious Diseases.

The Ethiopian team chose to test an oral rabies vaccine, called SAG2, that had been used successfully in red foxes. Twenty million baits had been dropped across Europe with no vaccine-induced rabies cases or reported deaths. SAG2 also passed safety tests in a slew of different species, including African wild dogs. “That work was absolutely fundamental,” Laurenson says.
Getting the vaccine into the animals is the trickiest part. Animals have to bite into the bait to puncture an internal packet that contains the vaccine, rather than swallow the bait whole. “You’ve got to make the bait such that the [wolf] would chew it,” says Anthony Fooks, a vaccine researcher who runs a U.K. government lab that handles sample tests for the wolf project.

So Sillero and his team launched a series of pilot studies of an oral SAG2. “We set up cafeteria-type experiments, with different baits and delivery methods,” Sillero says. The researchers dropped 445 baits in locations around Bale. Hiding the vaccine in goat meat and distributing the goods at night worked better than other options, the team reported in 2016 in Vaccine. Of 21 wolves trapped a couple of weeks later, 14, or 67 percent, carried a biomarker showing the vaccine was in the wolf’s system. Of those, 86 percent had developed immunity against rabies. The impact on other wildlife was low: Only a few raptors snatched up vaccines meant for the wolves.

With all that data in hand, Sillero’s team finally won over Ethiopia’s Wildlife Conservation Authority in December, receiving an official thumbs-up to move forward. This month, 4,000 vaccines arrived; the mass vaccination program could get off the ground this summer.

It’ll be the first mass oral vaccination program to target an endangered species in the wild. The basic plan: Distribute the oral vaccines at night once every two years, vaccinate at least 40 percent of a chosen wolf population and use motion-sensing cameras to see if each pack’s high-ranking males and females — the primary pup producers — take the bait. It’s important to keep the top producers healthy.
Drones and peanut butter
Having a readily available oral vaccine for the wolves was a lucky break for the researchers in Ethiopia. A research team in the United States had no such luck. Tonie Rocke and her colleagues had to develop their own oral plague vaccine for prairie dogs. The team devised a raccoon poxvirus that produces plague proteins once inside the prairie dog body. The proteins train the immune system to fight the plague-causing Yersinia bacteria.

Saving plague-ridden prairie dogs (Cynomys spp.) is an indirect way to protect the real target: an endangered predator, black-footed ferrets (Mustela nigripes) of the Great Plains. The ferrets survive on a diet of mostly prairie dogs and had nearly gone extinct in the 1970s due to centuries of habitat loss, prey declines and plague.
On top of captive breeding and reintroduction programs to keep the ferret species afloat, the U.S. Fish and Wildlife Service traps and vaccinates wild ferrets directly. But it’s not enough.

Rocke and her colleagues went ahead and developed a peanut butter–flavored oral plague vaccine. They distributed it by drones and four-wheelers in small test plots in seven states to limit prairie dog carriers. (Plague can threaten prairie dog populations too, so everybody wins.)

Last June, the researchers published the results of these successful small-scale field trials in EcoHealth. A prairie dog’s odds of surviving in plague-ridden areas just about doubled. And the peanut butter pellets were as good at reducing plague levels as traditional insecticides that kill plague-carrying fleas. It’s unclear just how many prairie dogs in colonies need to be vaccinated to protect the ferrets from plague.

Getting the vaccine approved wasn’t as tortuous as it has been in Ethiopia. Collaborators at Colorado Parks and Wildlife already had a cheap way to make the baits, and in 2017, Colorado Serum Company licensed the product through the U.S. Department of Agriculture.

This year, Rocke hopes to conduct larger-scale field trials to determine the levels of immunity required for success in a mass vaccination. Ultimately, the application will be limited — just selected populations of prairie dogs that are either in ferret territory or endangered themselves, such as the Utah prairie dog (C. parvidens). Plague infects a handful of humans and domesticated animals each year as well, and the team is looking into using the vaccine in areas where humans spend time, like national parks.
Encouraging others
Success for one species could be good news for others. Similar preventative strategies might work in other threatened animals, including other members of the dog family dealing with rabies and ungulates like zebras at risk of catching anthrax while grazing. Researchers are testing preventative vaccines to protect wild Hawaiian monk seals from a seal-specific distemper virus.

Oral vaccines aren’t the only nontraditional delivery method. Rocke’s lab is working on a topical vaccine against white-nose syndrome, which threatens bats (SN Online: 3/31/16), and one to combat rabies in common vampire bats (Desmodus rotundus). Vampire bats in particular nuzzle each other during social grooming. “It’s an easy way to get the vaccine distributed amongst members of the colony,” Rocke says.

In October in PLOS Neglected Tropical Diseases, her lab reported that the vaccine works in captured big brown bats (Eptesicus fuscus), but it still hasn’t been tested in vampire bats, key rabies carriers in South America. Rocke and colleagues hope to start trials in vampire bats this year in Mexico and Peru.

Great apes can fall victim to some of the same pathogens as humans, such as measles and Ebola. In March 2017 in Scientific Reports, a research team published successful lab tests of an oral vaccine against Ebola in captive chimpanzees (Pan troglodytes). The vaccine relies on the rabies virus to deliver Ebola proteins that elicit an immune response in chimps, but it hasn’t been tested in the field yet.

Such a vaccine should be used selectively, Kock says. Vaccinating great apes against Ebola in preserves where the animals might encounter human carriers makes sense. But vaccinating gorillas across large forests in the Congo “is just silly,” he says.

Protecting isolated species on the brink of extinction is where vaccines could do the most good. Endangered Amur tigers (Panthera tigris altaica) have been hit hard by canine distemper, their numbers falling to around 500 individuals in their Siberian habitat. Vaccines have been debated as a potential option and injectables have been tested in captive tigers.

Sillero doesn’t expect to see any oral options developed against distemper in the future, because there’s not a big economic incentive. Unlike rabies, the disease doesn’t cause problems in humans. So he’s working with the shots available. Genetic analyses of locally circulating distemper strains published in July 2017 suggest the injectable distemper vaccines should work for the Ethiopian wolves, Fooks says. Sillero’s team is testing one in the field now. Preliminary data suggest the shot elicits a good immune response.
What’s good for the wildlife
Greater awareness about the overlap of human, livestock and wildlife health on shared lands underlies many of these projects. Ethiopia has one of the highest rabies death rates among humans in the world, and lowering the disease prevalence in any animals that humans come in contact with has benefit.

“This will have positive impacts for the threatened animals, for the welfare of domestic dogs and livestock, and for the health and finance of the human community,” Sillero argues. The One Health mind-set is also behind programs run in a few areas of Ethiopia’s northern highlands, to teach local farmers how to build more efficient stoves that require less firewood, and thus, less foraging in wolf territory.

“Vaccination and eradication of things like rabies … needs a whole of society approach,” Kock says. “It cannot be done piecemeal.”

For Ethiopia’s impending oral vaccine launch that has been so many years in the making, Sillero is optimistic. But he’s still holding his breath.

“I have to see the wolves taking up the baits before I can congratulate the team,” he says. “But I think we’re nearly there.”

Kid-friendly e-cigarette ads appear to work

In the United States, cartoon characters are a no-no in cigarette ads, and candy- or fruit-flavored cigarettes can’t be sold. But that’s not the case for e-cigarettes, and these youth-appealing tactics are luring teens who have never used tobacco products to give e-cigs and even cigarettes a try, a new study suggests.

Researchers analyzed surveys of nearly 7,000 kids ages 12 to 17 who had never used a tobacco product as of 2013 to 2014. Teens who recalled seeing or liking e-cigarette ads were 1.6 times as likely to be open to trying e-cigs or to actually try them the next year as kids who didn’t remember the ads, researchers report online March 26 in JAMA Pediatrics. E-cig ads often feature celebrities, cartoons (one product shows a unicorn vomiting a rainbow) or references to sweet flavors, such as Skittles.
Past research has shown a link between traditional cigarette advertisements and receptive nonsmoking adolescents going on to light up. Nearly nine out of 10 smokers tried their first cigarette by age 18. Gearing traditional cigarette ads toward teens has been restricted since 1998.

In 2016, more than 2.1 million U.S. middle and high school students reported using e-cigarettes. That same year, an estimated 20.5 million — or four in five — were exposed to e-cigarette ads.

But e-cigarette ads are doing more than hyping vaping, the study suggests. The ads also appeared to nudge some teens and young adults to take up cigarette smoking. Of a larger group of about 10,500 kids ages 12 to 21 who had never used tobacco products, 18 percent recalled seeing or liking e-cigarette ads but not cigarette ads. Five percent of those teens had started to smoke by the next year.

Extrapolating to the U.S. population, “105,000 12- to 21- year olds appear to have smoked their first cigarette because of the influence of e-cigarette advertising,” says John Pierce, a behavioral epidemiologist at the University of California, San Diego.
Previous research has found that teens who use e-cigarettes are more likely to smoke traditional cigarettes (SN: 9/19/15, p. 14). The fact that e-cigarette ads may up the risk of smoking “raises an unprecedented concern for adolescent tobacco control,” addiction psychologist Adam Leventhal and epidemiologist Jessica L. Barrington-Trimis, both of the University of Southern California’s Keck School of Medicine in Los Angeles, write in an accompanying editorial in the journal.

In an interview, Leventhal adds that restricting such advertising is an important target for public health campaigns and policies to limit youth use of tobacco products.

Birds get their internal compass from this newly ID’d eye protein

Birds can sense Earth’s magnetic field, and this uncanny ability may help them fly home from unfamiliar places or navigate migrations that span tens of thousands of kilometers.

For decades, researchers thought iron-rich cells in birds’ beaks acted as microscopic compasses (SN: 5/19/12, p. 8). But in recent years, scientists have found increasing evidence that certain proteins in birds’ eyes might be what allows them to see magnetic fields (SN: 10/28/09, p. 12).

Scientists have now pinpointed a possible protein behind this “sixth sense.” Two new studies — one examining zebra finches published March 28 in Journal of the Royal Society Interface, the other looking at European robins published January 22 in Current Biology — both single out Cry4, a light-sensitive protein found in the retina. If the researchers are correct, this would be the first time a specific molecule responsible for the detection of magnetic fields has been identified in animals.
“This is an exciting advance — we need more papers like these,” says Peter Hore, a chemist at the University of Oxford who has studied chemical reactions involved in bird navigation.

Cry4 is part of a class of proteins called cryptochromes, which are known to be involved in circadian rhythms, or biological sleep cycles (SN: 10/02/17, p. 6). But at least some of these proteins are also thought to react to Earth’s magnetic field thanks to the weirdness of quantum mechanics (SN: 7/23/16, p. 8). The protein’s quantum interactions could help birds sense this field, says Atticus Pinzon-Rodriguez, a biologist at the University of Lund in Sweden who was involved with the zebra finch study.

To figure out which of three cryptochromes is responsible for this quantum compass, Pinzon-Rodriguez and his colleagues examined the retinas, muscles and brains of 39 zebra finches for the presence of the three proteins Cry1, Cry2 and Cry4.
The team found that while levels of Cry1 and Cry2 followed a rhythmic pattern that rose and fell over the day, Cry4 levels remained constant, indicating the protein was being produced steadily.

“We assume that birds use magnetic compasses any time of day or night,” says Lund biologist Rachel Muheim, a coauthor on the zebra finch study.

European robins also showed constant levels of Cry4 during a 24-hour cycle, and higher levels during their migratory season. And the researchers in that study found Cry4 in an area of the robin’s retina that receives a lot of light — a position that would help it work as a compass, the study says.

“We have quite a lot of evidence, but [Cry4] is not proven,” says Henrik Mouritsen, an animal navigation expert at the Institute of Biology and Environmental Sciences in Oldenburg, Germany, who participated in the robin study. More definitive evidence might come from observing birds without a functioning Cry4 protein, to see if they still seem to have an internal compass.

Even then, Hore says, we still may not understand how birds actually perceive magnetic fields. To know, you’d have to be a bird.

Why touch can be such a creepy sensation in VR

There’s a fine line between immersive and unnerving when it comes to touch sensation in virtual reality.

More realistic tactile feedback in VR can ruin a user’s feeling of immersion, researchers report online April 18 in Science Robotics. The finding suggests that the “uncanny valley” — a term that describes how humanoid robots that look almost but not quite human are creepier than their more cartoonish counterparts — also applies to virtual touch (SN Online: 11/22/13).
Experiment participants wearing VR headsets and gripping a controller in each hand embodied a virtual avatar holding the two ends of a stick. At first, users felt no touch sensation. Then, the hand controllers gave equally strong vibrations every half-second. Finally, the vibrations were finely tuned to create the illusion that the virtual stick was being touched in different spots. For instance, stronger vibrations in the right controller gave the impression that the stick was nudged on that side.

Compared with scenarios in which users received either no touch or even buzzing sensations, participants reported feeling far less immersed in the virtual environment when they received the realistic, localized touch. This result demonstrates the existence of a tactile uncanny valley, says study coauthor Mar Gonzalez-Franco, a human-computer interaction researcher at Microsoft Research in Redmond, Washington.

But when users were shown a marble touching the virtual stick wherever they felt the localized touch, the participants found this realistic tactile feedback highly immersive rather than bothersome. The finding indicates that rich tactile feedback in VR may need to be paired with other sensory cues that explain the source of the sensation to avoid spooking users, Gonzalez-Franco says.

Better understanding how realistic touch sensations can break the VR illusion may help developers create more engaging virtual environments for games and virtual reality therapy, says Sean Follmer, a human-computer interaction researcher at Stanford University not involved in the study.

This meteorite’s diamonds hint that it was born in a lost planet

A chunk of space rock may have been forged inside a long-lost planet from the early solar system. Tiny pockets of iron and sulfur embedded in diamonds inside the meteorite probably formed under high pressures found only inside planets the size of Mercury or Mars, researchers suggest April 17 in Nature Communications.

The parent planet no longer exists, though — it was smashed to smithereens in the solar system’s violent infancy.

“We probably have in our hands a piece of one of these first planets that have disappeared,” says Philippe Gillet of École Polytechnique Fédérale de Lausanne, or EPFL, in Switzerland.
EPFL physicist Farhang Nabiei, Gillet and their colleagues analyzed minuscule fragments of the Almahata Sitta meteorites. These meteorites are famous for coming from the first-ever asteroid tracked from orbit to ground as it streaked to the Nubian desert in Sudan in 2008 (SN: 4/25/09, p. 13).
The meteorites belong to a class called ureilites, which have compositions different from those in any of the known stony planets in the solar system. These ureilites contain 100-micrometer diamonds — too large to have been formed in the shock of two asteroids colliding. Such diamonds could form, however, inside asteroids that are at least 1,000 kilometers in diameter, where pressures would be high enough to compress carbon.
But the researchers discovered an oddity that made them question whether the gems came from an asteroid at all: The diamonds had grown around even smaller crystals of iron and sulfur, which normally would repel each other like oil and water, says EPFL physicist Cécile Hébert.

Those crystals would be stable only at pressures above 20 gigapascals, almost 200,000 times atmospheric pressure at sea level on Earth. “That can only be at the center of a very large planet” the size of Mercury, about 4,900 kilometers wide, or in the core-mantle boundary of a planet as large as Mars, about 6,800 kilometers wide, Hébert says.

Such planets probably roamed the early solar system some 4 billion years ago. But only a few survived to become the four rocky planets that exist today. Simulations of the early solar system suggest most of these early planets crashed into each other and broke apart in the first 100 million years.

“We are confirming the existence of such former planets,” Gillet says.

Those planets’ existence alone isn’t surprising, says cosmochemist Meenakshi Wadhwa of Arizona State University in Tempe. “This is the first time, though, that there is direct meteoritic evidence for the existence of a large protoplanetary body in the early solar system that is no longer in existence,” she says.
Not so fast, says cosmochemist Martin Bizzarro of the Natural History Museum of Denmark in Copenhagen. The protoplanet explanation isn’t the only one possible.

“They’ve done very careful work,” he says, but more needs to be done. Testing for remnant magnetic fields could reveal if the meteorites were once within a large planet’s molten core, for instance. Whether the meteorites came from a protoplanet is “still an open question.”

A DIY take on the early universe may reveal cosmic secrets

A DIY universe mimics the physics of the infant cosmos, a team of physicists reports. The researchers hope to use their homemade cosmic analog to help explain the first instants of the universe’s 13.8-billion-year life.

For their stand-in, the scientists created a Bose-Einstein condensate — a state of matter in which atoms are chilled until they all take on the same quantum state. Shaped into a tiny, rapidly expanding ring, the condensate grew from about 23 micrometers in diameter to about four times that size in just 15 milliseconds. The behavior of that widening condensate re-created some of the physics of inflation, a brief period just after the Big Bang during which the universe rapidly ballooned in size (SN Online: 12/11/13) before settling into a more moderate expansion rate.
In physics, seemingly unrelated systems can have similarities under the hood. Scientists have previously used Bose-Einstein condensates to simulate other mysteries of the cosmos, such as black holes (SN: 11/15/14, p. 14). And the comparison between Bose-Einstein condensates and inflation is particularly apt: A hypothetical substance called the inflaton field is thought to drive the universe’s extreme expansion, and particles associated with that field, known as inflatons, all take on the same quantum state, just as atoms do in the condensate.

Scientists still don’t fully understand how inflation progressed, “so it’s hard to know how close our system is to what really happened,” says experimental physicist Gretchen Campbell of the Joint Quantum Institute in College Park, Md. “But the hope is that our system can be a good test-bed” for studying various theories. Already, the scientists have spotted several effects in their system similar to those predicted in the baby cosmos, the team reports April 19 in Physical Review X.

As the scientists expanded the ring, sound waves that were traveling through the condensate increased in wavelength. That change was similar to the way in which light became redshifted — stretched to longer wavelengths and redder colors — as the universe enlarged.
Likewise, Campbell and colleagues saw a phenomenon akin to what’s known as Hubble friction, which shows up as a decrease in the density of particles in the early universe. In the experiment, this effect appeared in the guise of a weakening in the strength of the sound waves in the condensate.
And inflation’s finale, an effect known as preheating that occurs at the end of the rapid expansion period, also had a look-alike in the simulated universe. In the cosmic picture, preheating occurs when inflatons transform into other types of particles. In the condensate, this showed up as sound waves converting from one type into another: waves that had been sloshing inward and outward broke up into waves going around the ring.

However, the condensate wasn’t a perfect analog of the real universe: In particular, while our universe has three spatial dimensions, the expanding ring didn’t. Additionally, in the real universe, inflation proceeds on its own, but in this experiment, the researchers forced the ring to expand. Likewise, there were subtle differences between each of the effects observed and their cosmic counterparts.

Despite the differences, the analog universe could be useful, says theoretical cosmologist Mustafa Amin of Rice University in Houston. “Who knows?” he says. “New phenomena might happen there that we haven’t thought about in the early universe.”

Sometimes, when research crosses over between very different systems — such as Bose-Einstein condensates and the early universe — “sparks can fly,” Amin says.

This self-driving car could one day take you on a real road trip

A new kind of navigation system could help self-driving cars take the road less traveled.

Most autonomous vehicles test-driving in cities navigate using 3-D maps marking every curbside and off-ramp with almost centimeter-level precision (SN Online: 11/21/17). But there are millions of miles of open road that tech companies aren’t likely to plot in such detail any time soon.

Researchers now have developed a new autonomous navigation system that guides vehicles without such high-res maps, according to research being presented May 22 at the IEEE International Conference on Robotics and Automation in Brisbane, Australia. Cars equipped with this tech could hit the road for excursions off the beaten path.
The navigation system charts a course down unfamiliar roads much like a human driver would — by continually scanning its surroundings, albeit with a laser sensor, to gauge how close it is to the edges of the road. Meanwhile, the car also follows a tool akin to a smartphone map app that provides GPS directions to its destination, as well as information about the rules of the road — like speed limits and the positions of stoplights — along the car’s journey.

This system assumes that a car has a clear path down the road, but it could be paired with other existing algorithms that use laser sensing to detect in-road obstacles, like other vehicles or pedestrians, to navigate more heavily trafficked roadways, says study coauthor Teddy Ort, a roboticist at MIT.

Ort and colleagues test-drove a car equipped with this navigation system on a one-lane road winding through a forest in Devens, Mass. The vehicle slowly cruised along a one-kilometer stretch without requiring any human intervention to keep it on the right track. The researchers plan to build a version of this system that can spot lane markings painted on streets, so that the car can drive on more than one-way roads, Ort says.
The technology may be useful for future self-driving cars on cross-country road trips, though such vehicles would probably still use meticulous 3-D maps to weave through city traffic, says Raghvendra Cowlagi, an aerospace engineer at Worcester Polytechnic Institute in Massachusetts who wasn’t involved in the work.

Self-driving cars with this navigation system may also need other kinds of sensors to work in different conditions, says Alexander Wyglinski, an electrical and computer engineer also at Worcester Polytechnic Institute not involved in the study. Since laser sensors don’t work well in rain or snow, for example, these cars might need additional imaging technologies to drive safely in inclement weather (SN: 12/24/16, p. 34).