In a chorus of indris, young males vie for the spotlight, riffing in alternation rather than singing in unison. Not content to be the Joey Fatone of the group, these guys strive for Justin Timberlake status.
Indris (Indri indri), the only singing lemur species, begin their songs with roars that descend into long, phrased howls. These choirs are composed of males and females, with one dominant pair. Marco Gamba of the University of Turin in Italy and his colleagues wanted to analyze variation among individual singers.
Listening to 496 indri songs recorded over 10 years in the dense forests of Madagascar, the team found that pitch varies between males and females. And indri groups typically sing in synchrony, amplifying their tunes and vocally marking their territory to other groups. When one singer starts to croon, the others join in and match rhythm.
Solos are rare, but young male singers tend to sing out of sync — probably to stand out and advertise their masculinity, Gamba and his colleagues propose June 14 in Frontiers in Neuroscience.
There are degrees of slothfulness, it turns out, even when it comes to sloths. And three-toed sloths may be the most slothful of them all: A species of the animal has a field metabolic rate that is the lowest ever recorded for any mammal in the world.
Jonathan Pauli, an ecologist at the University of Wisconsin-Madison, got interested in sloths not because they’re adorable but because “other things eat them,” he says. And he stayed interested in the animals because they are “biologically fascinating.”
Sloths are a type of arboreal folivore, a group that includes all animals that live in trees and eat only leaves. What most people lump into the category of “sloth” are really six species in two families (two-toed and three-toed) separated by millions of years of evolution. Both families live in trees in Central and South America and eat leaves, but three-toed sloths tend to have smaller ranges and more constricted diets, eating from only a few species of trees and only a limited number of them. Studies have also shown that these sloths have a very slow metabolic rate.
But how slow? To find out, Pauli and his colleagues captured 10 brown-throated three-toed sloths (Bradypus variegatus) and 12 Hoffmann’s two-toed sloths (Choloepus hoffmanni) from a study site in northeastern Costa Rica. There, the sloths live among a variety of habitat types, ranging from pristine forest to cacao agroforest to monocultures of banana and pineapple. “It’s really a quilt of different habitat types,” Pauli says, and one that allows the researchers to not only study many habitats at once but also more easily capture and track sloths than if they were in dense jungle.
The researchers injected the sloths with water labeled with isotopes of oxygen and hydrogen and released the animals, tracking them with radiotelemetry. After a week to a week and a half, the scientists again captured the sloths and took blood samples. By seeing how much of the oxygen and hydrogen isotopes remained, the scientists could calculate the sloths’ field metabolic rate — the energy that an organism uses throughout the day.
The field metabolic rate for the three-toed sloths was 31 percent lower than that of two-toed sloths and lower than that found in any mammal outside of hibernation, the researchers report May 25 in the American Naturalist.
“There seems to be kind of a cool combination of behavior and physiological characteristics that lead to these tremendous cost savings for three-toed sloths,” Pauli says. Three-toed sloths spend a lot of time in the canopy eating and sleeping, he notes. “They don’t do a lot of movement, whereas two-toed sloths are much more mobile. They’re moving around a lot more.”
But it’s more than just that. “Three-toed sloths have the capacity to fluctuate their body temperature,” he says. Unlike humans, who need to keep their temperature within a few degrees to function properly, the sloths can let theirs rise and fall with the ambient temperature, a bit like how a lizard or snake might regulate its body temperature. “Those are big cost savings to let your body change with your surroundings.”
The results of the study help explain why there aren’t more kinds of sloths and other arboreal folivores, Pauli and his colleagues argue. “Being an arboreal folivore is really tough living,” Pauli says. Leaf eaters tend to be big because they need to accommodate a large digestive system capable of processing all the leaf matter they need to survive. But to live in the trees, an animal can’t be too big. And this could be why arboreal folivory is one of the world’s rarest lifestyles. The need for all the various adaptations for that lifestyle could prevent the rapid diversification seen among other groups, such as Darwin’s finches.
Fierce combat erupted in February 2016 at the northern Iraqi village of Kudilah. A Western-backed coalition of Arab Sunni tribesmen, Kurds in the Iraqi army and Kurdish government forces advanced on Islamic State fighters who had taken over the dusty outpost.
Islamic State combatants, led by young men wearing explosive vests, fought back. The well-trained warriors scurried through battle lines until they reached their enemy. Then they blew themselves up along with a few coalition soldiers, setting the stage for an Islamic State victory. These suicide bombers are called inghamasi, meaning “those who dive in deep.” The inghamasi’s determination and self-sacrifice inspires their comrades to fight to the death, says anthropologist Scott Atran of the University of Michigan in Ann Arbor. Outnumbered about 6-to-1, Islamic State fighters still retained control of Kudilah after two days of heavy fighting. Coalition forces retreated, unwilling to lose more soldiers.
Atran and colleagues arrived in northern Iraq a couple of weeks later. Their plan: study “the will to fight” among soldiers on both sides of the Kudilah clash, even as fighting in the area continued. Their goals: try to understand what motivates people to join brutal organizations such as the Islamic State, and describe the personal transformations that push people leading comfortable, peaceable lives to commit acts of incredible violence and self-destruction.
Atran wondered whether there were common individual traits that explain the fierce devotion held by fighters for the Islamic State (also known as ISIS, ISIL or Daesh) as well as troops trying to take down ISIS. Scientists typically treat extreme sacrifice for others as premised on a careful weighing of pros and cons by “rational actors” who behave in a way that best satisfies their own interests even if others benefit as well. But it’s hard to see how a “what’s in it for me” formula applies to inghamasi, Atran says, much less someone who operates in a more conventionally altruistic way, such as a Navy SEAL. It’s a mistake to write off ISIS fighters as lonely losers, each seeking death as a gateway to a heavenly rendezvous with a private stock of virgins, he contends. To break out of the rational-actor rut, Atran shifted his experimental focus nearly a decade ago to examine cherished values that mobilize people to take collective action, regardless of risks or rewards. In the last several years, he has moved his studies to the field, to focus on combatants in current conflicts and their sympathizers. And he’s finding that extreme personal sacrifices made for outfits such as the Islamic State can be understood, but only by accounting for values he describes as “sacred” and by tracking the way in which individuals identify with like-minded comrades.
Collective identity Academics who study warfare and terrorism typically don’t conduct research just kilometers from the front lines of battle. But taking the laboratory to the fight is crucial for figuring out what impels people to make the ultimate sacrifice to, for example, impose Islamic law on others, says Atran, who is affiliated with the National Center for Scientific Research in Paris.
Atran’s war zone research over the last few years, and interviews during the last decade with members of various groups engaged in militant jihad (or holy war in the name of Islamic law), give him a gritty perspective on this issue. He rejects popular assumptions that people frequently join up, fight and die for terrorist groups due to mental problems, poverty, brainwashing or savvy recruitment efforts by jihadist organizations.
Instead, he argues, young people adrift in a globalized world find their own way to ISIS, looking to don a social identity that gives their lives significance. Groups of dissatisfied young adult friends around the world — often with little knowledge of Islam but yearning for lives of profound meaning and glory — typically choose to become volunteers in the Islamic State army in Syria and Iraq, Atran contends. Many of these individuals connect via the internet and social media to form a global community of alienated youth seeking heroic sacrifice, he proposes.
Preliminary experimental evidence suggests that not only global terrorism, but also festering state and ethnic conflicts, revolutions and even human rights movements — think of the U.S. civil rights movement in the 1960s — depend on what Atran refers to as devoted actors. These individuals, he argues, will sacrifice themselves, their families and anyone or anything else when a volatile mix of conditions are in play. First, devoted actors adopt values they regard as sacred and nonnegotiable, to be defended at all costs. Then, when they join a like-minded group of nonkin that feels like a family — a band of brothers — a collective sense of invincibility and special destiny overwhelms feelings of individuality. As members of a tightly bound group that perceives its sacred values under attack, devoted actors will kill and die for each other.
His team’s studies of devoted actors may help to explain why a growing number of people from around the world are leaving their families and home nations to join ISIS. Congressional and United Nations reports suggest that by October 2015, nearly 30,000 recruits from more than 100 countries had become fighters in Syria and Iraq, primarily for the Islamic State.
“The rise of the Islamic State is a revolutionary movement of historic proportions,” Atran says. “Many of its members are devoted actors with an apocalyptic belief that they must destroy the world to save it.” That uncompromising vision feeds off the promise of a global caliphate — a joint political and Islamic entity that kills or controls nonbelievers — that will bring on the end of the world and replace it with God’s true kingdom. Volunteers to that cause have participated in more than 50 terror attacks in 20 countries since June 2014. Muslim militants carried out 450 suicide bombing attacks in 2015, with 174 attributed to the Islamic State.
Atran’s research may provide a rare tool to study soldiers’ will to fight, whether or not they’re Islamic State adherents, says psychologist and terrorism researcher John Horgan of Georgia State University in Atlanta. Too many investigators have dismissed those deemed to be terrorists “as either incomprehensible or not even worthy of understanding,” Horgan says.
At the time of the Kudilah battle, the Islamic State controlled hundreds of thousands of square kilometers in the Middle East. It had successfully defended a 3,000-kilometer-long military front stretching from Iraq to Syria against multi-national forces. It’s certainly possible to destroy the Islamic State with overwhelming military might, Atran says, but that approach would come at a price. It would leave a fragmented Sunni Muslim world, from which the Islamic State arose, as well as a global pool of passionate young men and women seeking liberation through sacrifice and martyrdom. A military takedown alone might trigger “a volcanic resurgence of rebels with a cause, even readier for doomsday,” he predicts.
Sacred apocalyptic values are best opposed by the spread of deeply held, life- and freedom-affirming values that supporters are willing to defend unconditionally, Atran argues. The Kurds have had success with this approach.
Sacred kin In the Middle East, only Kurdish people living in northern Iraq have consistently held off Islamic State attacks. The Kurds, Atran finds, display a will to fight equal to that of captured Islamic State fighters. As important as guns and other material support are to a military operation, an indomitable will to fight may be even more crucial, he says. Both the Islamic State and the Kurdish army have achieved considerable military success without all the hardware of Western armies.
At Kudilah, Kurdish soldiers showed their mettle in a fierce clash. Several of these men later described the event to Atran. As Iraqi army units withdrew, Islamic State forces rapidly pushed forward. A small company of Kurds stood their ground. After the fight raged for several hours, Iraqi army reinforcements arrived, enabling the Kurds to live to fight another day.
Atran’s team interviewed 28 Kurdish soldiers plus 10 Kurds who provided supplies, medical care and other frontline assistance. Seven Islamic State fighters, six of them prisoners, also agreed to be interviewed. One had been freed and changed sides, working with groups opposed to the Islamic State.
Among the 38 Kurdish volunteers, 22 reported devotion to a homeland of “Kurdistan” as a sacred value that they would fight and die for, even overriding family ties and their Islamic religion, Atran reports in the June Current Anthropology. All but one of the 22 reported feeling a collective bond, or what Atran calls identity fusion, with the Kurdish people.
Captured ISIS members reported visceral, family-like bonds with their fellow fighters. All Islamic State prisoners cited an absolute commitment to an imposition of Islamic law, or Sharia, on nonbelievers.
Investigators measured identity fusion by presenting participants with touch-screen computer tablets showing a small circle labeled “me” and a large circle with a group label, such as “Kurds” or “family.” To represent their relationship to a particular group, individuals could move the circles together so that they partly or completely overlapped. Those who moved the small circle inside the large circle were regarded as fully fused with that group. Atran adopted this test from ongoing research initiated nearly a decade ago by psychologist William Swann of the University of Texas at Austin. An international team led by social anthropologist Harvey Whitehouse of the University of Oxford, including Swann, studied Libyan men who tried to overthrow their government in 2011. The researchers found that nearly all the men reported intense, family-like bonds with fellow combatants. Revolutionary leaders granted the researchers access to 42 Libyan soldiers and 137 support personnel, including mechanics and ambulance drivers, as hostilities wound down in late 2011.
On the overlapping circles test, 45 percent of fighters reported being more strongly bonded to their battalions of three to five comrades than to their families, the researchers reported in 2014 in the Proceedings of the National Academy of Sciences. A smaller portion of support personnel, 28 percent, identified more with revolutionary battalions than with their families. That’s consistent with the idea that frontline fighters most often bond tightly to their units, upping their readiness to give their lives for comrades.
Libyan soldiers who felt intense connections to their battalions probably qualified as devoted actors, says psychologist Hammad Sheikh of the New School for Social Research in New York City, who was not involved in Whitehouse’s study. The soldiers’ commitment to the revolution’s goals probably transcended even family loyalties, Sheikh suspects. He bases that opinion on Atran’s findings. Whitehouse’s team did not try to identify devoted actors among Libyan fighters.
People willing to sacrifice everything in defense of the Islamic State’s sacred values also exist outside of the war zone. Among 260 Moroccans who lived in either of two city neighborhoods known as pro-ISIS hotbeds, testing indicated that about 30 percent were devoted actors. They described the imposition of Sharia as a nonnegotiable necessity, Sheikh and his colleagues, including Atran, report in a second paper in the June Current Anthropology.
On the overlapping circles test, devoted actors in Morocco depicted especially close bonds with family-like groups of friends, ranging from Islamic State supporters to soccer buddies. Western weakness Such dedication to collective values may be tougher to come by in Western nations. Online testing of 644 people in Spain identified only 12 percent as devoted actors willing to sacrifice all for democracy, even after being reminded of threats by ISIS and Al Qaeda. Frequent corruption scandals have left many Spaniards disillusioned with democracy, Sheikh says. Whether a similarly weak devotion to democratic values applies to citizens of other European countries or the United States remains to be tested.
Field research suggests that collective commitments to democratic values may be weaker in the West. When devoted actors among Islamic State fighters, Kurds and members of a Kurdish-speaking religious community known as Yazidis were given a hypothetical choice between abandoning their sacred values if others in their group do, or leaving the group to fight on for their sacred values, they nearly always opted to fight on for their values, Atran says.
Devoted actors in Spain, however, typically say they’d follow their group if it rejected democratic values. People in France and Spain tested by Atran’s team also rate their own society’s “spiritual force,” or the strength of collective beliefs and commitments, as much weaker than that of ISIS.
Among U.S., British and former Soviet soldiers, there have long been indications from interviews, field reports and personal letters of a stronger willingness to die for close comrades in war than in defense of broader values, Atran says. Historical evidence, however, suggests that certain relentless fighters, including Nazi troops during World War II and Viet Cong soldiers in the Vietnam War, were devoted actors inspired by beliefs in a higher cause, he says, adding that the same may have been true for soldiers on both sides of the U.S. Civil War. Sacrificial appeal Atran and his colleagues now have their own cause: describing more fully how some people go from holding extreme beliefs on the sidelines to becoming devoted actors at the front lines of extreme movements.
It would help, says political psychologist Clark McCauley of Bryn Mawr College in Pennsylvania, if researchers could clarify what counts as a sacred value and why some sacred values outweigh others. Identity fusion is also a tricky concept to pin down, McCauley says. Further research needs to determine whether a person who moves a “me” circle inside a circle representing a fighting unit still feels a sense of individuality or totally buys into a collective identity, he suggests.
Only by venturing into war zones can researchers begin to understand the will to fight on all sides, from the perspectives of the fighters themselves, Atran argues. It’s daunting work. He has seen ISIS fighters advancing on an Iraqi army outpost, then detonating their explosive vests in the ultimate show of commitment to their cause. He has spoken to Kurdish veterans missing arms or legs and men who had joined the Kurdish army back in the 1950s, all of them now fighting at the front to defend their homeland.
A young Yazidi fighter told Atran that he used vacation time from college to train for a week with Kurdish Marxists in Syria to defend his Kurdish religious community against the Islamic State. Fighting with a few comrades in August 2014, the student-soldier fended off ISIS attackers long enough for reinforcements to arrive. He helped save thousands of Yazidis from slaughter. The young man then returned to his studies. He wanted to be an archaeologist.
“You learn more in five minutes in the field than in five years of analysis from afar,” Atran says.
Despite careful planning, Atran’s team sometimes gets distressingly close to warring parties while conducting research in Iraq. It’s an unavoidable risk but not a deal breaker for the researchers. “There’s something so compelling,” he says, “about trying to figure out humans in extreme circumstances such as war.” This article appears in the July 9, 2016, issue of Science News under the headline “Deadly devotion: New studies explore why ordinary people turn terrorist.”
Two days after my first daughter was born, her pediatrician paid a house call to examine her newest patient. After packing up her gear, she told me something alarming: “For the next few months, a fever is an emergency.” If we measured a rectal temperature at or above 100.4° Fahrenheit, go to the hospital, she said. Call her on the way, but don’t wait.
I, of course, had no idea that a fever constituted an emergency. But our pediatrician explained that a fever in a very young infant can signal a fast-moving and dangerous bacterial infection. These infections are rare (and fortunately becoming even rarer thanks to newly created vaccines). But they’re serious, and newborns are particularly susceptible.
I’ve since heard from friends who have been through this emergency. Their newborns were poked, prodded and monitored by anxious doctors, in the hopes of quickly ruling out a serious bacterial infection. For infants younger than two months, it’s “enormously difficult to tell if an infant is seriously ill and requires antibiotics and/or hospitalization,” says Howard Bauchner, a pediatrician formerly at Boston University School of Medicine and now editor in chief of the Journal of the American Medical Association.
A new research approach, described in two JAMA papers published in August, may ultimately lead to better ways to find the cause of a fever.
These days, for most (but not all) very young infants, their arrival at a hospital will trigger a workup that includes a urine culture and a blood draw. Often doctors will perform a lumbar puncture, more commonly known as a spinal tap, to draw a sample of cerebrospinal fluid from the area around the spinal cord.
Doctors collect these fluids to look for bacteria. Blood, urine and cerebrospinal fluid are smeared onto culture dishes, and doctors wait and see if any bacteria grow. In the meantime, the feverish infant may be started on antibiotics, just in case. But this approach has its limitations. Bacterial cultivation can take several days. The antibiotics may not be necessary. And needless to say, it’s not easy to get those fluids, particularly from a newborn.
Some scientists believe that instead of looking for bacteria or viruses directly, we ought to be looking at how our body responds to them. Unfortunately, the symptoms of a bacterial and viral infection are frustratingly similar. “You get a fever. You feel sick,” says computational immunologist Purvesh Khatri of Stanford University. Sadly, there are no obvious telltale symptoms of one or the other, not even green snot. In very young infants, a fever might be the only sign that something is amiss. But more subtle clues could betray the cause of the fever. When confronted with an infection, our immune systems ramp up in specific ways. Depending on whether we are fighting a viral or bacterial foe, different genes turn up their activity. “The immune system knows what’s going on,” Khatri says. That means that if we could identify the genes that reliably get ramped up by viruses and those that get ramped up by bacteria, then we could categorize the infection based on our genetic response.
That’s the approach used by two groups of researchers, whose study results both appear in the August 23/30 JAMA. One group found that in children younger than 2, two specific genes could help make the call on infection type. Using blood samples, the scientists found that one of the genes ramped up its activity in response to a viral infection, and the other responded to a bacterial infection.
The other study looked at immune responses in even younger children. In infants younger than 60 days, the activity of 66 genes measured in blood samples did a pretty good job of distinguishing between bacterial and viral infections. “These are really exciting preliminary results,” says Khatri, who has used a similar method for adults. “We need to do more work.”
Bauchner points out that in order to be useful, “the test would have to be very, very accurate in very young infants.” There’s very little room for error. “Only time will tell how good these tests will be,” he says. In an editorial that accompanied the two studies, he evoked the promise of these methods. If other experiments replicate and refine the results of these studies, he could envision a day in which the parents of a feverish newborn could do a test at home, call their doctor and together decide if the child needs more care.
That kind of test isn’t here yet, but scientists are working on it. The technology couldn’t come soon enough for doctors and parents desperate to figure out a fever.
Muscles don’t have long-term memory for exercises like running, biking and swimming, a new study suggests. The old adage that once you’ve been in shape, it’s easier to get fit again could be a myth, at least for endurance athletes, researchers in Sweden report September 22 in PLOS Genetics.
“We really challenged the statement that your muscles can remember previous training,” says Maléne Lindholm of the Karolinska Institute in Stockholm. But even if muscles forget endurance exercise, the researchers say, other parts of the body may remember, and that could make retraining easier for people who’ve been in shape before. Endurance training is amazingly good for the body. Weak muscle contractions, sustained over a long period of time — as in during a bike ride — change proteins, mainly ones involved in metabolism. This translates into more energy-efficient muscle that can help stave off illnesses like diabetes, cardiovascular disease and some cancers. The question is, how long do those improvements last?
Previous work in mice has shown that muscles “remember” strength training (SN: 9/11/10, p. 15). But rather than making muscles more efficient, strength-training moves like squats and push-ups make muscles bigger and stronger. The muscles bulk up as they develop more nuclei. More nuclei lead to more production of proteins that build muscle fibers. Cells keep their extra nuclei even after regular exercise stops, to make protein easily once strength training restarts, says physiologist Kristian Gundersen at the University of Oslo in Norway. Since endurance training has a different effect on muscles, scientists weren’t sure if the cells would remember it or not. To answer that question, Lindholm’s team ran volunteers through a 15-month endurance training experiment. In the first three months, 23 volunteers trained four times a week, kicking one leg 60 times per minute for 45 minutes. Volunteers rested their other leg. Lindholm’s team took muscle biopsies before and after the three-month period to see how gene activity changed with training. Specifically, the scientists looked for changes in the number of mRNAs (the blueprints for proteins) that each gene was making. Genes associated with energy production showed the greatest degree of change in activity with training. At a follow-up, after participants had stopped training for nine months, scientists again biopsied muscle from the thighs of 12 volunteers, but didn’t find any major differences in patterns of gene activity between the previously trained legs and the untrained legs. “The training effects were presumed to have been lost,” says Lindholm. After another three-month bout of training, this time in both legs, the researchers saw no differences between the previously trained and untrained legs. While this study didn’t find muscle memory for endurance — most existing evidence is anecdotal — it still might be easier for former athletes to get triathalon-ready, researchers say. The new result has “no bearing on the possible memory in other organ systems,” Gundersen says. The heart and cardiovascular system could remember and more easily regain previous fitness levels, for example, he says.
Even within muscle tissue, immune cells or stem cells could also have some memory not found in this study, says molecular exercise physiologist Monica Hubal of George Washington University in Washington, D.C. Lindholm adds that well-trained connections between nerves and muscles could also help lapsed athletes get in shape faster than people who have never exercised before. “They know how to exercise, how it’s supposed to feel,” Lindholm says. “Your brain knows exactly how to activate your muscles, you don’t forget how to do that.”
To human observers, bumblebees sipping nectar from flowers appear cheerful. It turns out that the insects may actually enjoy their work. A new study suggests that bees experience a “happy” buzz after receiving a sugary snack, although it’s probably not the same joy that humans experience chomping on a candy bar.
Scientists can’t ask bees or other animals how they feel. Instead, researchers must look for signs of positive or negative emotions in an animal’s decision making or behavior, says Clint Perry, a neuroethologist at Queen Mary University of London. In one such study, for example, scientists shook bees vigorously in a machine for 60 seconds — hard enough to annoy, but not hard enough to cause injury — and found that stressed bees made more pessimistic decisions while foraging for food. The new study, published in the Sept. 30 Science, is the first to look for signs of positive bias in bee decision making, Perry says. His team trained 24 bees to navigate a small arena connected to a plastic tunnel. When the tunnel was marked with a blue “flower” (a placard), the bees learned that a tasty vial of sugar water awaited them at its end. When a green “flower” was present, there was no reward. Once the bees learned the difference, the scientists threw the bees a curveball: Rather than being blue or green, the “flower” had a confusing blue-green hue.
Faced with the ambiguous color, the bees appeared to dither, meandering around for roughly 100 seconds before deciding whether to enter the tunnel. Some didn’t enter at all. But when the scientists gave half the bees a treat — a drop of concentrated sugar water — that group spent just 50 seconds circling the entrance before deciding to check it out. Overall, the two groups flew roughly the same distances at the same speeds, suggesting that the group that had gotten a treat first had not simply experienced a boost in energy from the sugar, but were in a more positive, optimistic state, Perry says.
In a separate experiment, Perry and colleagues simulated a spider attack on the bees by engineering a tiny arm that darted out and immobilized them with a sponge. Sugar-free bees took about 50 seconds longer than treated bees to resume foraging after the harrowing encounter.
The researchers then applied a solution to the bees’ thoraxes that blocked the action of dopamine, one of several chemicals that transmit rewarding signals in the insect brain. With dopamine blocked, the effects of the sugar treat disappeared, further suggesting that a change in mood, and not just increased energy, was responsible for the bees’ behavior.
The results provide the first evidence for positive, emotion-like states in bees, says Ralph Adolphs, a neuroscientist at Caltech. Yet he suspects that the metabolic effects of sugar did influence the bees’ behavior. Geraldine Wright, a neuroethologist at Newcastle University in England, shares that concern. “The data reported in the paper doesn’t quite convince me that eating sucrose didn’t change how they behaved, even though they say it didn’t affect flight time or speed of flight,” she says. “I would be very cautious in interpreting the responses of bees in this assay as a positive emotional state.”
It may sound like science fiction, but it’s not: Scientists have created the first time crystal, using a chain of ions. Just as a standard crystal repeats in a regular spatial pattern, a time crystal repeats in time, returning to a similar configuration at regular intervals.
“This is a remarkable experiment,” says physicist Chetan Nayak of Microsoft Station Q at the University of California, Santa Barbara. “There is a ‘wow factor.’”
Scientists at the University of Maryland and the University of California, Berkeley created a chain of 10 ytterbium ions. These ions behave like particles with spin, a sort of quantum mechanical version of angular momentum, which can point either up or down. Using a laser, the physicists flipped the spins in a chain of ions halfway around, from up to down, and allowed the ions to interact so that the spin of each ion would influence the others. The researchers repeated this sequence at regular intervals, flipping the ions halfway each time and letting them interact. When scientists measured the ions’ spins, on average the ions went full circle, returning to their original states, in twice the time interval at which they were flipped halfway. This behavior is sensible — if each flip turns something halfway around, it takes two flips to return to its original position. But scientists found that the ions’ spins would return to their original orientation at that same rate even if they were not flipped perfectly halfway. This result indicates that the system of ions prefers to respond at a certain regular period — the hallmark of a time crystal — just as atoms in a crystal prefer a perfectly spaced lattice. Such time crystals are “one of the first examples of a new phase of matter,” says physicist Norman Yao of UC Berkeley, a coauthor of the new result, posted online September 27 at arXiv.org.
Time crystals take an important unifying concept in physics — the idea of symmetry breaking — and extend it to time. Physical laws typically treat all points in space equally — no one location is different from any other. In a liquid, for example, atoms are equally likely to be found at any point in space. This is a continuous symmetry, as the conditions are the same at any point along the spatial continuum. If the liquid solidifies into a crystal, that symmetry is broken: Atoms are found only at certain regularly spaced positions, with voids in between. Likewise, if you rotate a crystal, on a microscopic level it would look different from different angles, but liquid will look the same however it’s rotated. In physics, such broken symmetries underlie topics ranging from magnets to superconductors to the Higgs mechanism, which imbues elementary particles with mass and gives rise to the Higgs boson.
In 2012, theoretical physicist Frank Wilczek of MIT proposed that symmetry breaking in time might produce time crystals (SN: 3/24/12, p. 8). But follow-up work indicated that time crystals couldn’t emerge in a system in a state of equilibrium, which is settled into a stable configuration. Instead, physicists realized, driven systems, which are periodically perturbed by an external force — like the laser flipping the ions — could create such crystals. “The original examples were either flawed or too simple,” says Wilczek. “This is much more interesting.”
Unlike the continuous symmetry that is broken in the transition from a liquid to a solid crystal, in the driven systems that the scientists used to create time crystals, the symmetry is discrete, appearing at time intervals corresponding to the time between perturbations. If the system repeats itself at a longer time interval than the one it’s driven at — as the scientists’ time crystal does — that symmetry is broken.
Time crystals are too new for scientists to have a handle on their potential practical applications. “It’s like a baby, you don’t know what it’s going to grow up to be,” Wilczek says. But, he says, “I don’t think we’ve heard the last of this by a long shot.” There probably are related systems yet to be uncovered, says Nayak. “We’re just kind of scratching the surface of the kinds of amazing phenomena — such as time crystals — that we can have in nonequilibrium quantum systems. So I think it’s the first window into a whole new arena for us to explore.”
There’s much more to the universe than meets the eye, and a new web-based app lets you explore just how much our eyes are missing. Gleamoscope presents the night sky across a range of electromagnetic frequencies. Spots of gamma rays pinpoint distant feeding black holes. Tendrils of dust glow with infrared light throughout the Milky Way. A supernova remnant — the site of a star that exploded roughly 11,000 years ago — blasts out X-rays and radio waves.
Many of these phenomena are nearly imperceptible in visible light. So astronomers use equipment, such as specialized cameras and antennas, that can detect other frequencies of electromagnetic radiation. Computers turn the data into images, often assigning colors to certain frequencies to highlight specific details or physical processes.
In Gleamoscope, a slider smoothly transitions the scene from one frequency of light to another, turning the familiar star-filled night sky into a variety of psychedelic landscapes. Pan and magnification controls allow you to scan all around the night sky and zoom in for a closer look. The interactive map combines images from many observatories and includes new data from the Murchison Widefield Array, a network of radio antennas in Australia. Over 300,000 galaxies appear as dots in images of the new radio data, described in an upcoming issue of Monthly Notices of the Royal Astronomical Society. The radio map by itself can also be explored on mobile devices in a separate app called GLEAM, available on Google Play.
There’s no bow or festive wrap, but I hope that you will consider this issue a gift of sorts. That is how the staff of Science News thinks of it, our year-end recap of the top science stories. In these pages, you’ll find the stories that continued to resonate well after we first covered them and many that we expect will resonate for years to come — all collected in one easy-to-read, extremely portable, no-batteries-required package (unless you are reading this on a smartphone or tablet, that is). Gravitational waves, of course, occupy the top spot on our list this year. The “of course” reflects the fundamental importance of the detection of this elusive form of energy, announced in February. The finding confirmed key theories in physics, sure, but even more exciting is what it promises for the future. Gravitational waves are powerful tools for probing the universe. Just as the Hubble Space Telescope revealed cosmic beauty in electromagnetic radiation, gravitational wave detectors may show scientists an unprecedented view of far-off Closer to home, the Zika virus became one of our most closely watched stories this year, as the extent of human suffering caused by the mosquito-borne virus became clear. But it’s also a tale of progress: Scientists have responded swiftly, creating a robust literature on the virus in a short time. We still don’t have all the answers, but we’ve come a long way in terms of creating the knowledge urgently needed to inform health recommendations.
Other stories made this year’s list with a more mixed pedigree. The discovery of a (relatively) nearby exoplanet energized many of our science fiction–fueled fantasies of other worlds, for instance. Research moved ahead on what some call “three-parent babies” — using mitochondrial donors to replace a woman’s own disease-prone mitochondria in egg cells — despite a lack of clarity on the procedure’s efficacy. Melting Arctic sea ice has led to a historically significant opening of passageways between the Pacific and the Atlantic oceans. New hope for the battle against Alzheimer’s disease seemed worthy of mention. All these developments and more were regarded by Science News reporters and editors as milestones of discovery or news of importance to society.
We also decided to add some other elements to our year-in-review coverage for 2016. Guided by the deft hand of Beth Quill, our enterprise editor, we augmented our Top 10 list with an essay by managing editor Tom Siegfried about two of physics’s noteworthy recent failures and how the two are related. Science journalist and author Sonia Shah offers a roundup of 2016 in public health, reminding us of the thorny problems associated with infectious diseases, from antibiotic resistance to the resurgence of yellow fever. Other pieces illustrate some of the challenges facing the driverless car revolution, as well as what Science News reporters see on the horizon for the coming year.
We have tried to pack as much science as possible into this issue, from the biggest stories to the more obscure nuggets of discovery and surprise. I can’t think of a gift I’d more like to receive.
Fossils of a giant otter have emerged from the depths of an open-pit mine in China.
The crushed cranium, jaw bone and partial skeletons of at least three animals belong to a now-extinct species of otter that lived some 6.2 million years ago, scientists report January 23 in the Journal of Systematic Palaeontology.
At roughly 50 kilograms in weight, the otter would have outclassed today’s giant otter, a river-dwelling South American mammal weighing in at around 34 kilograms. Scientists named the new species Siamogale melilutra, a nod to its unusual mix of badger and otter features. Melilutra is a mash-up of the Latin words for both creatures.
Badgers and otters both belong to a group of carnivorous animals called Mustelidae, but scientists have had trouble figuring out where to place extinct members in the mammalian family tree. (European badgers and modern otters share similar-looking teeth and skulls.) Still, Siamogale melilutra, however badgerlike, is indeed an otter, researchers concluded after CT scanning, reconstructing and analyzing the fossil skull.
Based on plant and animal fossils found near the collection site, scientists believe that the ancient otter probably lived in the shallow lake of a warm and humid swamp, lush with broad-leaved evergreens and grasses.
