Pluto has no rings — New Horizons triple-checked. An exhaustive search for rings and dust particles around the dwarf planet before, during and after the spacecraft flew past Pluto in 2015 has come up empty.

“It’s a very long paper to say we didn’t find anything,” says team member Tod Lauer of the analysis, posted online September 23 at arXiv.org. But the nonresult could help scientists understand the contents of the outer solar system — and help plan New Horizons’ next encounter. The spacecraft is now on a course to a space rock in the Kuiper Belt, another 1.5 billion kilometers past Pluto.
Before New Horizons arrived at Pluto, the possible existence of rings was an urgent matter of safety. Hitting a particle as small as a sand grain could have damaged the spacecraft.

Searches with the Hubble Space Telescope in 2011 and 2012 turned up two previously unknown moons orbiting Pluto — Kerberos and Styx (SN: 11/28/15, p. 14) — and zero rings. Even so, many researchers expected to encounter rings, or at least some debris. The four outer planets in the solar system have rings, as do other small bodies in the solar system, like the tiny planetoid 10199 Chariklo (SN: 5/3/14, p. 10). And some studies suggest that Pluto probably had rings at one point in its past, left over from the collision that formed its largest moon, Charon.

Nine weeks before New Horizons’ closest approach to Pluto, a team jokingly called the “crow’s nest” acted much like a ship’s lookout for potential hazards, says Lauer, an astronomer with the National Optical Astronomy Observatory in Tucson, Ariz. The group examined images taken with the spacecraft’s Long Range Reconnaissance Imager camera, looking for ring particles reflecting sunlight or spots that moved against a starry background from one set of images to the next. Nothing turned up.

The team declared the spacecraft’s trajectory safe, and New Horizons flew sailed safely past Pluto on July 14, 2015 (SN Online: 7/15/15). After the flyby, the team turned New Horizons around to look back at Pluto, and towards the sun. This was a much better position to look for rings, as dust particles would pop into view when backlit by the sun like motes of dust in the light from a window.

“If you really want to know for sure whether there’s any dust there, the viewing geometries where you’re looking past the dust with the sun in the background, that’s the gold standard,” says Matthew Tiscareno of the SETI Institute in Mountain View, Calif., who studied Saturn’s rings with the Cassini spacecraft but was not involved in New Horizons.
It took the better part of a year for all the data from New Horizons to return to Earth, and several months after that to analyze it, but the team is now ready to call it: The rings really aren’t there — or at least they’re too diffuse to see.

That’s somewhat surprising, Lauer says. But the chaotic gravity of Pluto’s family of moons might make it too hard for rings to find stable orbits. Or the slight pressure generated by light particles streaming from the sun could constantly blow would-be ring particles away.

It’s also possible there just wasn’t that much dust there to begin with. New Horizons saw fewer craters on Pluto and Charon than expected, which could mean there are fewer small bodies at that distance from the sun smacking into Pluto and its moons and kicking up dust.

That could be good news for New Horizons’ next act. After five months in hibernation, the spacecraft woke up on September 11 and has set its sights on a smaller, weirder and more distant object: a space rock about 30 kilometers long called 2014 MU69 (SN Online: 7/20/17). Initial observations suggest it might be a double object, with two bodies orbiting closely or touching lightly.

New Horizons will fly past MU69 on January 1, 2019. In the meantime, the team is looking for hazards along the route. “We’re going to do a similar effort to what we did with Pluto,” Lauer says. “We’re going to get in the crow’s nest and get out our binoculars, as it were, and see if we’re going to be okay.”

A 26-year-old woman felt something in her left eye. For days, she couldn’t shake the sensation. But this was no errant eyelash or dive-bombing gnat.

A week after that first irritation, the Oregon resident pulled a translucent worm, about a centimeter long, from her eye. With that harrowing feat, she became the first ever reported case of a human infestation with the cattle eyeworm, Thelazia gulosa. “This is a very rare event and exciting from a parasitological perspective,” says medical parasitologist Richard Bradbury of the U.S. Centers for Disease Control and Prevention in Atlanta. “Perhaps not so exciting if you are the patient.”
Over 20 days, she and her doctors removed 14 worms from her infected eye, researchers report online February 12 in the American Journal of Tropical Medicine and Hygiene. After that, no more irritation.

T. gulosa is a nematode found in North America, Europe, Australia and central Asia. It infects the large, watchful eyes of cattle. The worm spends its larval stage in the abdomen of the aptly named face fly, Musca autumnalis. As the fly feasts on tears and eye secretions, it spreads the nematode larva, which then grow into adult worms.

Two other Thelazia species are known to infect humans, but rarely. There have been more than 160 cases reported for one species in Europe and Asia, and only 10 cases in North America, by a species found in dogs. This new perpetrator was not expected to be seen in a human, Bradbury says.

The young woman had been horseback riding near cattle farms in Gold Beach, Oregon, which may explain her face-to-face with the fly.
“It is just unfortunate for the patient,” Bradbury says, “that she was not able to swish away that one infected fly quickly enough from her eye.”

AUSTIN, Texas — Babies’ stroke-damaged brains can pull a mirror trick to recover.

A stroke on the left side of the brain often damages important language-processing areas. But people who have this stroke just before or after birth recover their language abilities in the mirror image spot on the right side, a study of teens and young adults shows. Those patients all had normal language skills, even though as much as half of their brain had withered away, researchers reported February 17 at the annual meeting of the American Association for the Advancement of Science.
Researchers so far have recruited 12 people ages 12 to 25 who had each experienced a stroke to the same region of their brain’s left hemisphere just before or after birth. People who have this type of stroke as adults often lose their ability to use and understand language, said study coauthor Elissa Newport, a neurology researcher at Georgetown University Medical Center in Washington, D.C.

MRI scans of healthy siblings of the stroke patients showed activity in language centers in the left hemisphere of the brain when the participants heard speech. The stroke patients showed activity in the exact same areas — just on the opposite side of the brain.

It’s well established that if an area of the brain gets damaged, other brain areas will sometimes compensate. But the new finding suggests that while young brains have an extraordinary capacity to recover, there might be limits on which areas can pinch-hit.

“When you look at a very well-defined population, recovery takes place in a very particular set of regions,” said Newport. Young children usually show language activity in the same areas on both sides of their brain, Newport noted, and the left side becomes more dominant over time. But in the case of a major stroke to the left side, the corresponding areas on the right side of the brain might already be primed to take over.

Two newly discovered giant viruses have the most comprehensive toolkit for assembling proteins found in any known virus. In a host cell, the viruses have the enzymes needed to wrangle all 20 standard amino acids, the building blocks of life.

Researchers dubbed the viruses Tupanvirus deep ocean and Tupanvirus soda lake, combining the name of the indigenous South American god of thunder, Tupan, with the extreme environment where each type of virus was found. The giant viruses are among the largest of their kind — up to 2.3 micrometers in length — which is about 23 times as long as a particle of HIV, the scientists report February 27 in Nature Communications.
Tupanviruses can infect a wide range of hosts, such as protists and amoebas, but pose no threat to humans, the researchers say.

Viruses are considered nonliving, but the genetic complexity of giant viruses has some scientists questioning that categorization. Each Tupanvirus, for example, has a massive genetic instruction book with roughly 1.5 million base pairs of DNA, more than what some bacteria have, says coauthor Bernard La Scola, a virologist at Aix-Marseille University in France.

But other scientists say giant viruses aren’t so different from their smaller kin. Research by Frederik Schulz, with the Department of Energy Joint Genome Institute in Walnut Creek, Calif., suggests these microscopic behemoths are regular viruses that acquired extra genes from hosts and should not be classified as life.

Tupanviruses don’t settle the controversy, but they do challenge our preconceptions of what life is, La Scola says.

To quickly unfurl and refold their wings, earwigs stretch the rules of origami.

Yes, those garden pests that scurry out from under overturned flowerpots can also fly. Because earwigs spend most of their time underground and only occasionally take to the air, they pack their wings into packages with a surface area more than 10 times smaller than when unfurled, using an origami-like series of folds. Springy wing joints let the insects bypass some of the mathematical constraints that normally limit the way a rigid two-dimensional material can be folded, researchers report March 23 in Science.
Earwig wings’ folding pattern should be impossible according to mathematical equations that predict the three-dimensional designs that can be made by folding a two-dimensional material like a sheet of paper, says study coauthor Andres Arrieta, a mechanical engineer at Purdue University in West Lafayette, Ind.

Origami theory assumes that the material being folded is perfectly rigid. But the joints of earwigs’ wings — where creases form — are rich in a rubbery polymer called resilin. This little bit of stretch lets earwig wings do what a regular origami structure can’t: lock into two different conformations, open or folded up, and transition between the two.
It’s an example of a bistable structure — something like the slap bracelets, popular in the 1980s and 1990s, which switch from a flat conformation to a curved one when whacked against a wrist, says study coauthor André Studart, a materials scientist at ETH Zürich. When locked open, earwig wings store energy in the springy resilin joints. When that strain is released, the wings rapidly crumple back to their folded position.
Such constructions can inform robotics design. Inspired by the wings, the researchers created a prototype gripper. Its rigid pieces are held together by rubbery, strategically placed joints. Within fractions of a second, the structure can snap from its mostly flat conformation to one that can grip a small object and hold it without constant external force.
While other materials scientists have pushed the limits of origami by making flat pieces bendable, this design instead stretches the hinges, says Jesse Silverberg, a physicist at Harvard University who wasn’t part of the study. Such a design has been observed and discussed, but never before been implemented in this way.

The earwig “is a beautiful example of how nature uses slight extensions to ideal mathematical origami to do something amazing,” says Itai Cohen, a physicist at Cornell University who wasn’t part of the study.

Perhaps that’s a slight redemption for the much-maligned insect.

When you’re pregnant, especially for the first time, you have to make a lot of decisions. Will coffee remain a part of your life? Where are you going to give birth? What are you going to name the baby? What values will you teach him? Do you really need a baby spa bathtub?

Before my first daughter arrived, an instructor at a birth class threw me a curveball: Was I planning on banking my baby’s umbilical cord blood?
For much of pregnancy, the umbilical cord is the lifeline of a fetus, tethering it to the placenta. Snaking through the nearly 2-feet-long cord, there’s a vein ferrying nutrients and oxygen from mom’s blood (via the placenta), plus two arteries carrying oxygen- and nutrient-depleted blood from the fetus back to mom. Because mother’s blood and fetal blood don’t actually mix much, the blood in the placenta and umbilical cord at birth belongs mainly to the fetus.

That fetal blood holds all sorts of interesting — and potentially therapeutic — cells and molecules. This realization has, in some cases, changed the way the umbilical cord and placenta are handled during birth. Instead of tossing it aside, some doctors, scientists and parents are choosing to bank this fetal blood — harvesting it from the baby’s umbilical cord and placenta, freezing it and storing it away for later.

Proponents of cord blood banking are convinced that instead of being medical waste, the fetal cells within are biological gold. In this post, and the two that follow, I’ll take a look at the evidence for those claims, and sort through some of the questions that arise as parents consider whether to bank their baby’s cord blood.

Back in the 1980s, umbilical cord blood caught the attention of researchers who suspected that the often-discarded tissue could be a valuable source of shape-shifting stem cells. These cells, which can become several different types of blood cells, are similar to the specialized stem cells found in bone marrow that can churn out new blood cells. Such stem cells are found in adult blood, too, but not as abundantly.
In 1988, a 5-year-old named Matthew with a rare type of anemia received umbilical cord blood cells from his newborn sister, who didn’t have the disease. That transfer, called an umbilical cord blood transplant, worked, and the boy was soon free of the disease.

At the time, researchers didn’t know much about the properties of the cells found in umbilical cord blood. But research has zoomed forward, illuminating more about the contents of this young blood.

Of particular interest are the flexible hematopoietic stem cells important in that initial transplant. In certain cases, transplanting these cells might be able to reboot a person’s body and get rid of a disease-related defect. Cord blood transplants are similar to bone marrow transplants. A person with leukemia, for instance, might have his own cancerous blood cells wiped out with chemotherapy and radiation. Healthy, non-cancerous stem cells from a donor can then repopulate the blood.

Extracting stem cells from bone marrow requires surgery under anesthesia; extracting them from the blood requires taking a drug to stimulate their production. And in order to work, these stem cell donations need to come from a person who carries a similar pattern of proteins on the outsides of his or her cells, a molecular calling card known as HLA type. Stem cells found in cord blood don’t need to be as closely matched to work. Because these cells are so flexible, there’s more wiggle room between donor and recipient. That’s particularly good news for people of certain ethnic minorities who often have trouble finding matched stem cell transplant donors.

Hard numbers are tricky to pin down, but between that first transplant in 1988 and 2015, an estimated 35,000 umbilical cord blood transplants had been performed globally. That number includes people treated for leukemia and other types of cancer, blood disorders and immune diseases. And the utility of umbilical cord cells may stretch well beyond the disorders that the cells are currently being used for. “If you read the literature, it’s pretty exciting,” says pediatrician and immunologist William Shearer of Baylor College of Medicine and Texas Children’s Hospital.

Some researchers suspect that umbilical cord blood contains other cells that may have therapeutic effects beyond the blood. Specialized immune cells may be able to tweak brain function, for instance. Trials around the world are studying umbilical cord blood’s capabilities in a wide range of diseases (see Table 2 here): Cerebral palsy, autism, diabetes and lupus are currently under investigation. The cells are even being tested for an ameliorating role in Alzheimer’s disease and other neurodegenerative conditions.

After injections with their own umbilical cord blood, 63 children with cerebral palsy improved on motor skills, on average. And a clinical trial to see whether cord blood transplants improve symptoms of children with autism spectrum disorder should wrap up in the summer of 2018, says pediatric researcher and clinician Joanne Kurtzberg of Duke University, who helped establish a not-for-profit umbilical cord bank in North Carolina. (A small but optimistic pilot study has already been completed.)

The potential powers of these cells have researchers excited. But what that scientific hope means for expectant parents facing decisions about cord blood banking is far from clear. For all of the promise, there are lots of reasons why umbilical cord cells may turn out to be less useful than thought. Read my next post for more about these potential drawbacks.

Greenland is melting rapidly, but some glaciers are disappearing faster than others. A new map of the surrounding seafloor helps explain why: Many of the fastest-melting glaciers sit atop deep fjords that allow Atlantic Ocean water to melt them from below.

Researchers led by glaciologist Romain Millan of the University of California, Irvine analyzed new oceanographic and topographic data for 20 major glaciers within 10 fjords in southeast Greenland. The mapping revealed that some fjords are several hundred meters deeper than simulations of the bathymetry suggested, the researchers report online March 25 in Geophysical Research Letters. These troughs allow warmer and saltier waters from deeper in the ocean to reach the glaciers and erode them.
Other glaciers are protected by shallow sills, or raised seafloor ledges. These sills act as barriers to the deep, warm water, the new seafloor maps show. The researchers compared their findings with observations of glacier melt from 1930 to 2017, and found that the fastest-melting glaciers tended to be those more exposed to melting from below.
The study uses data from two NASA missions — Operation IceBridge, which measures ice thickness and gravity from aircraft, and Oceans Melting Greenland, or OMG, which uses sonar and gravity instruments to map the shape and depth of the seafloor close to the ice front. The OMG mission also involves dropping hundreds of probes into the ocean each year to measure temperature and salinity at different depths.
Scientists have long suspected Greenland’s melting may be accelerated by the ocean (SN Online: 7/6/11), but needed data on fjord depth and glacier thickness to prove it.

The high-resolution OMG datasets, in particular, reveal bumps and troughs in the seafloor that were previously unknown, says glaciologist Andy Aschwanden at the University of Alaska Fairbanks, who was not involved with the study. “Those small details can make quite a difference to when a glacier will retreat.”

Just a few tweaks to a bacterial enzyme make it a lean, mean plastic-destroying machine.

One type of plastic, polyethylene terephthalate, or PET, is widely used in polyester clothing and disposable bottles and is notoriously persistent in landfills. In 2016, Japanese scientists identified a new species of bacteria, Ideonella sakaiensis, which has a specialized enzyme that can naturally break down PET.

Now, an international team of researchers studying the enzyme’s structure has created a variant that’s even more efficient at gobbling plastic, the team reports April 17 in Proceedings of the National Academy of Sciences.

The scientists used a technique called X-ray crystallography to examine the enzyme’s structure for clues to its plastic-killing abilities. Then, they genetically tweaked the enzyme to create small variations in the structure, and tested those versions for PET-degrading performance. Some changes made the enzyme work even better. Both the original version and the mutated versions could break down both PET and another, newer bio-based plastic called PEF, short for polyethylene-2,5-furandicarboxylate. With a little more engineering, these enzymes could someday feast at landfills.

Ancient surgeons may have practiced dangerous skull-opening procedures on cows before operating on people.

A previously excavated cow skull from a roughly 5,400- to 5,000-year-old settlement in France contains a surgically created hole on the right side, a new study finds. No signs of bone healing, which start several days after an injury, appear around the opening. One or more people may have rehearsed surgical techniques on a dead cow, or may have tried unsuccessfully to save a sick cow’s life in what would be the oldest known case of veterinary surgery, researchers conclude online April 19 in Scientific Reports.

Evidence of skull surgery on humans, whether for medical or ritual reasons, goes back about 11,000 years (SN: 5/28/16, p. 12). Ancient surgeons needed to know how and where to scrape away bone without harming brain tissue and blood vessels. So practicing bone removal on cows or other animals is plausible.

The ancient cow’s skull opening, shaped almost in a square and framed by scrape marks, resembles two instances of human skull surgery from around the same time in France, say biological anthropologists Fernando Ramirez Rozzi of CNRS in Montrouge, France, and Alain Froment of IRD-Museum of Man in Paris. Microscopic and X-ray analyses found no fractures or splintered bone that would have resulted from goring by another cow’s horn. No damage typical of someone having struck the cow’s head with a club or other weapon appeared, either.

Club-wielding assailants struck the Scandinavian settlement with devastating violence, slaughtering at least 26 people and leaving the bodies where they fell. There, the bodies lay for 1,500 years until recovered recently by archaeologists analyzing clues about the Iron Age massacre.

It’s unclear why the seaside ringfort of Sandby borg, on the Baltic Sea island of Ӧland, was targeted at a time of political turmoil following the Roman Empire’s fall in Western Europe. Adults, teenagers and children died suddenly and brutally — their skeletons showing bones fractured by clubs, but no defensive wounds, say archaeologist Clara Alfsdotter of Bohuslӓns Museum in Udevalla, Sweden, and her colleagues. When the slaughter was over, the attackers left the sheep and other animals to starve and the valuables untouched, the scientists report in the April Antiquity. No one came back to bury the dead.
That’s somewhat unusual: At most other excavated battlefield and massacre sites in Europe, bodies have been found in mass graves ( SN: 1/23/16, p. 7). However, 67 farming villagers slaughtered around 7,200 years ago at Austria’s Asparn-Schletz site were also left in place. Circumstances surrounding the attacks on Asparn-Schletz and Sandby borg are poorly understood, making it difficult to compare the two events, says anthropologist Bruno Boulestin of the University of Bordeaux in France, who did not participate in the excavation.
The bones from Sandby borg have yet to undergo radiocarbon dating, making it impossible to say precisely when the massacre occurred, says archaeologist Ian Armit of the University of Bradford in England, who did not participate in the Sandby borg research. But the researchers suspect the killing happened after 476, when the fall of the Western Roman Empire left a power vacuum and power struggles broke out across parts of Europe and southern Scandinavia. Sandby borg’s attackers may have installed themselves as the new local rulers, the team suggests.

“It was not the killing that was the point, but the statement toward those witnessing it from a distance that ‘if you mess with us, this is what happens,’” says study coauthor Ludvig Papmehl-Dufay of Kalmar County Museum in Sweden.

Sandby borg, spanning roughly 5,000 square meters contained by an eroded oval stone wall, has been a center for archaeological excavations since 2011. Aerial photographs and ground surveys have revealed stone structures buried inside the ringfort off Sweden’s southeast coast. Investigators have located 53 houses, some within a central block circled by a street. By 2016, two houses had been fully excavated and seven others had undergone some investigation. Inside, researchers found gilded silver brooches, glass beads and silver bell pendants, in styles suggesting the fort was occupied in the late 400s.
In one house, the skeletons of nine individuals of various ages were found. Their positions suggested they had been surprised by the attack, say Alfsdotter, Papmehl-Dufay and coauthor Helena Victor, also of Kalmar County Museum. One teenage boy appears to have fallen backward over an adult victim. Two corpses showed evidence of being partially burned, suggesting the attackers tried unsuccessfully to set the structure on fire or that a fire accidentally broke out. A tiny half skeleton from a herring lay next to the fireplace, adding support to the theory that the attackers left quickly without touching or eating anything. A pile of lamb skeletons stacked in the corner and showing signs of recent slaughter suggests the attack occurred sometime between late spring and early fall, the researchers say.

Scientists are working on radiocarbon dating the Sandby borg skeletons as the annual excavations continue, Papmehl-Dufay says. With more than 90 percent of the ringfort settlement yet to be excavated, there are likely more clues to the killing to be found.