Two cosmic magnifying glasses are giving astronomers a glimpse of some extremely faint galaxies that existed as far back as 600 million years after the Big Bang (13.8 billion years ago). Such views suggest that tiny galaxies in the early universe played a crucial role in cosmic reionization — when ultraviolet radiation stripped electrons from hydrogen atoms in the cosmos.

“That we detected galaxies as faint as we did supports the idea that a lot of little galaxies reionized the early universe and that these galaxies may have played a bigger role in reionization than we thought,” says Rachael Livermore, an astronomer at the University of Texas at Austin. She and colleagues report the results in the Feb. 1 Astrophysical Journal.
The team identified the dim galaxies in images taken with the Hubble Space Telescope while it was pointed at two closer clusters of galaxies. Those clusters act as a gravitational lens, brightening and magnifying the light of fainter objects much farther away. Subtracting the clusters’ light revealed distant galaxies up to one-tenth as bright as those spotted in previous studies (SN Online: 11/4/15).

Finding such faint galaxies implies that stars can form in much smaller galaxies than models have predicted and that there were enough of these small galaxies to drive reionization almost entirely by themselves. Reionization radically refashioned the universe so that charged atoms instead of neutral ones pervaded space. Understanding that transition may help astronomers explain how stars and galaxies arose in the early universe.

“Such measurements are really challenging to make,” says Brant Robertson, an astronomer at the University of California, Santa Cruz, who was not involved with the study. “They’re really at the forefront of this field, so there are some questions about the techniques the team used to detect these galaxies and determine how bright they actually are.”

A team of astronomers led by Rychard Bouwens of Leiden University in the Netherlands argues in a paper submitted to the Astrophysical Journal and posted October 2 online at arXiv.org that Livermore and colleagues haven’t, in fact, detected galaxies quite as faint as they have claimed. That keeps the door open for other objects, such as black holes accreting matter and spitting out bright light, to have played a part in reionization.

Robertson says the disagreements motivate further work, noting that Livermore and colleagues used a clever approach to spot what appear to be superfaint galaxies in the early universe. Now, the teams will have to see if that technique stands the test of time.

Livermore and colleagues plan to use the technique to search for faint galaxies lensed by other clusters Hubble has observed. Both teams, along with Robertson, are also looking to the October 2018 launch of the James Webb Space Telescope, which should be able to spot even fainter and more distant galaxies, to determine what drove reionization in the early universe.

Traces of Zika virus typically linger in semen no longer than three months after symptoms show up, a new study on the virus’ staying power in bodily fluids reveals.

Medical epidemiologist Gabriela Paz-Bailey of the U.S. Centers for Disease Control and Prevention and colleagues analyzed the bodily fluids — including blood, urine and saliva — of 150 people infected with Zika. In 95 percent of participants, Zika RNA was no longer detectable in urine after 39 days, and in blood after 54 days, researchers report February 14 in the New England Journal of Medicine. (People infected with dengue virus, in contrast, typically clear virus from the blood within 10 days, the authors note.)

Although the CDC recommends that men exposed to Zika wait at least six months before having sex without condoms, researchers found that, for most men in the study, Zika RNA disappeared from semen by 81 days.

Few people had traces of RNA in the saliva or in vaginal secretions. Most Zika infections transmitted sexually have been from men to women, but scientists have reported at least one female-to-male case.

Black holes are a bit like babies when they eat: Some food goes in, and some gets flung back out into space. Astronomers now say they understand how these meals become so messy — and it’s a trait all black holes share, no matter their size.

Magnetic fields drive the turbulent winds that blow gas away from black holes, says Keigo Fukumura, an astrophysicist at James Madison University in Harrisonburg, Va. Using X-rays emitted from a relatively small black hole siphoning gas from a nearby star, Fukumura and colleagues traced the winds flowing from the disk of stellar debris swirling around the black hole. Modeling these winds showed that magnetism, not other means, got the gas moving in just the right way.
The model was previously used to explain the way winds flow around black holes millions of times the mass of the sun. Showing that the model now also works for a smaller stellar-mass black hole suggests that magnetism may drive winds in black holes of all sizes. These results, published online March 6 in Nature Astronomy, could give clues to how black holes consume and expel matter and also to why some galaxies stop forming stars.

Astronomers first proposed that magnetic fields powered the winds around black holes in the 1970s, but the idea has been controversial. Directly observing the winds is impossible. Their existence is inferred by a black hole’s X-ray spectrum — an inventory of light broken up by wavelength.

In 2005, astronomers used the Chandra X-ray Observatory to capture the X-ray spectrum of a relatively puny black hole with seven times the mass of the sun. The companion star it feeds on has about twice the heft of the sun. The system, called GRO J1655-40, is about 11,000 light-years away in the constellation Scorpius.

GRO J1655-40’s X-rays revealed its turbulent winds. Some astronomers argued the data provided evidence that powerful magnetic fields fueled the winds. Others, however, suggested the winds resulted from extremely hot gas swirling around the black hole.

“I think the new paper clears this controversy up,” says Andrew Fabian, an astrophysicist at the University of Cambridge who was not involved with the new study. The model Fukumura developed, he says, is extremely detailed and accounts for characteristics of GRO J1655-40’s X-ray spectrum that other models can’t explain.
Features of the spectrum, for example, suggest that the winds are dense and move moderately quickly, but don’t blow far from the black hole. That matches models of magnetically fueled wind. Models related to the heat of the gas alone make the winds blow too far.

The magnetic fields form from the electric current generated by electrons and protons swirling in a pancake-shaped accretion disk. Parts of the disk spin around the black hole at different speeds, which amplifies the fields. That, in turn, turns the accretion disk into a vortex, pulling matter into the black hole and fueling winds that blow some of it outward.

“A good fraction of the mass actually gets kicked out of the black hole,” Fukumura says. “If it didn’t get thrown off, we wouldn’t see it.”

The magnetic fields probably arc around the black hole from pole to pole. But no one knows for sure because they are hard to detect. Recently, the Event Horizon Telescope, which pointed several telescopes at the center of the Milky Way, did spot patterns in the way the light of our galaxy’s central, supermassive black hole was oriented that signaled it has magnetic fields. Astronomers plan to use the telescope array to search for more evidence of magnetic fields around black holes next month.

Studying the magnetic fields of black holes reveals information about the structure of their accreting disks and the winds that blow from them. “Winds from black hole disks can be very powerful,” Fabian notes. “In the case where the black hole is massive and at the center of a galaxy, the wind can push all the gas out of the host galaxy, stopping further star formation and causing the galaxy to appear red and dead.”

Some bedbugs are better climbers than others, and the bloodsuckers’ climbing prowess has practical implications.

To detect and monitor bedbugs, people use an array of strategies from DIY setups to dogs. Pitfall traps, which rely on smooth inner walls to prevent escape, are highly effective for detecting and monitoring an infestation. The traps are sold around the world, but they have only been tested with common bedbugs (Cimex lectularius) — the most, well, common species in the United States.

As it turns out, tropical bedbugs (C. hemipterus) can easily scale the walls of pitfall traps, Chow-Yang Lee, an entomologist at Malaysia’s University of Science, and his colleagues found in lab tests. While 24 to 76 percent of tropical bedbug strains escaped traps, only 0 to 2 percent of common strains made it out. In measurements of vertical frictional force, tropical bedbugs also came out on top. Further investigation of the species’ feet revealed extra hairs on the tibial pads of tropical bugs. These may give their legs a better grip on trap walls, the researchers propose March 15 in the Journal of Economic Entomology.

Tropical bedbugs live in some regions of Africa, Australia, Japan, China and Taiwan — and have recently resurfaced in Florida.

Many babies born early spend extra time in the hospital, receiving the care of dedicated teams of doctors and nurses. For these babies, the hospital is their first home. And early experiences there, from lights to sounds to touches, may influence how babies develop.

Touches early in life in the NICU, both pleasant and not, may shape how a baby’s brain responds to gentle touches later, a new study suggests. The results, published online March 16 in Current Biology, draw attention to the importance of touch, both in type and number.

Young babies can’t see that well. But the sense of touch develops early, making it a prime way to get messages to fuzzy-eyed, pre-verbal babies. “We focused on touch because it really is some of the basis for communication between parents and child,” says study coauthor Nathalie Maitre, a neonatologist and neuroscientist at Nationwide Children’s Hospital in Columbus, Ohio.

Maitre and her colleagues studied how babies’ brains responded to a light puff of air on the palms of their hands — a “very gentle and very weak touch,” she says. They measured these responses by putting adorable, tiny electroencephalogram, or EEG, caps on the babies.

The researchers puffed babies’ hands shortly before they were sent home. Sixty-one of the babies were born early, from 24 to 36 weeks gestation. At the time of the puff experiment, they had already spent a median of 28 days in the hospital. Another group of 55 babies, born full-term, was tested in the three days after birth.

Full-term babies had a strong brain reaction to the hand puff. (This reaction was missing when researchers pointed the air nozzle away from the babies, a control that ruled out the effects of the puff’s sound.) Preterm babies had weaker brain reactions to the hand puff, the researchers found.

But the story doesn’t stop there. The researchers also looked at the number and type of touches — positive or negative — the preemies received while in the hospital.
Preemies who received a greater number of positive early touches, such as breastfeeding, skin-to-skin cuddles and massage, had stronger brain responses to the puffs than preemies who received fewer. More worryingly, preemies who had a greater number of negative touch experiences, including heel pricks, IV insertions, injections and tape removal, tended to have diminished brain responses to the puffs.

About a third of the premature babies in the study didn’t receive any positive touches that the researchers counted. Between birth and the time of the hand-puff experiment, the median number of positive touch experiences for the preemies in the study was 4. In contrast, the median number of painful procedures was 32.

The study turns up links, not cause. That means scientists can’t say whether the early touches, both positive and negative, are behind the differences in brain response. But it’s possible that early tactile experiences pattern the brain in important ways, Maitre says. If so, then the results have big implications.

Oftentimes, parents don’t have the luxury of snuggling their baby, particularly when parental leave is limited and babies are being treated far from home. Nurses, doctors and other medical professionals provide other forms of care. But anything parents, medical professionals or even volunteer cuddlers can do to shift the balance of positive and negative touches might encourage babies’ development, giving these smallest and newest of people the best start possible.

A black hole weighing more than a billion suns appears to have gotten the boot toward the outer edges of its galaxy.

Data from the Hubble Space Telescope and other observatories reveal a supermassive black hole zipping away from the center of its galaxy at a 7.5-million-kilometer-per-hour clip. It’s moving so quickly that it could leave the galaxy for good in 20 million years, says Marco Chiaberge of the Space Telescope Science Institute in Baltimore.
Only gravitational waves — ripples in the fabric of spacetime — could give the black hole such a kick, Chiaberge and colleagues report March 30 in Astronomy & Astrophysics. Hints of huge black holes ejected from a galactic center have been reported before (SN: 5/24/08, p. 12). This discovery offers some of the most convincing evidence that black holes can get kicked out of their galaxies by gravitational waves and suggests that it occurs more often than astronomers thought.

“This is a very nice candidate for a recoiling supermassive black hole,” says Francesca Civano of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. Recoiling black holes are created when two monster black holes from different galaxies merge, says Civano, who was not involved in the new study. If the black holes have different masses and rotate at different rates, the collision can generate gravitational waves more strongly in one direction, booting the newly merged black hole the other way.

A radiation-gushing supermassive black hole called quasar 3C 186 and its host galaxy, about 8 billion light-years from Earth in the constellation Lynx, tipped off Chiaberge and colleagues to the recoiling black hole. The team noticed that the quasar wasn’t at the center of the galaxy, where it typically should be. “We knew this was clearly weird. It was clearly different than all of the other quasars and galaxies we were seeing,” Chiaberge says.

The team calculated that the quasar was 35,000 light-years from its host galaxy’s center — about 10,000 light-years more than the distance separating the sun and the center of the Milky Way. 3C 186 is a well-studied object, so the team sifted through past observations of the quasar and galaxy and found data revealing how fast the gas surrounding the monster black hole moves. The researchers compared it with how fast the star-forming gas in the galaxy moves. The monster black hole was traveling much more quickly, with a velocity that would have to come from something forceful, equivalent to 100 million stars exploding simultaneously. Gravitational waves could provide such a kick.

The Hubble images also revealed curved wisps of stars and gas extending from the galaxy. Such faint tails suggest that the galaxy collided with another galaxy in the past, giving weight to the team’s claim that gravitational waves from colliding black holes could have given 3C 186 its kick.

Evidence of recoiling black holes is hard to find, but it’s the easiest explanation for the data in the new paper, Civano says. The new work, she notes, also suggests recoiling black holes could be more common than astronomers thought, but missed in earlier observations. “They might just be hidden in well-known sources, like 3C 186,” she says.

The heavy-duty material used to build bridges and sculpt skyscrapers could learn a few tricks from humble bones.

Steel’s weakness is its tendency to develop microscopic cracks that eventually make the material fracture. Repeated cycles of stress — daily rush hour traffic passing over a bridge, for example — nurture these cracks, which often aren’t apparent until the steel collapses. Bones, however, have a complex inner structure that helps them deal with stress. This structure differs depending on the scale, with tiny vertically aligned fibers building up into larger cylinders.
To mimic this variability, researchers fabricated steel with thin, alternating nanoscale layers of different crystal structures, some of which were just unstable enough to morph a bit under stress. That complicated microstructure prevented cracks from spreading in a straight line, slowing their take-over and preventing the material from collapsing, the scientists report in the March 10 Science. This experimental steel requires much more testing before it can be used in construction, says study coauthor C. Cem Tasan, a materials scientist at MIT. But the principles could be applied to other mixed-composition metals, too.

Soon after systems biologist Juergen Hahn published a paper describing a way to predict whether a child has autism from a blood sample, the notes from parents began arriving. “I have a bunch of parents writing me now who want to test their kids,” says Hahn, of Rensselaer Polytechnic Institute in Troy, N.Y. “I can’t do that.”

That’s because despite their promise, his group’s results, reported March 16 in PLOS Computational Biology, are preliminary — nowhere close to a debut in a clinical setting. The test will need to be confirmed and repeated in different children before it can be used to help diagnose autism. Still, the work of Hahn and colleagues, along with other recent papers, illustrates how the hunt for a concrete biological signature of autism, a biomarker, is gaining speed.
Currently, pediatricians, child psychologists and therapists rely on behavioral observations and questionnaires, measures with limitations. Barring genetic tests for a handful of rare mutations, there are no blood draws, brain scans or other biological tests that can reveal whether a child has — or will get — autism.

Objective tests would be incredibly useful, helping provide an early diagnosis that could lead to therapy in the first year of life, when the brain is the most malleable. A reliable biomarker might also help distinguish various types of autism, divisions that could reveal who would benefit from certain therapies. And some biomarkers may reveal a deeper understanding of how the brain normally develops.

Scientists are simultaneously sanguine and realistic about the prospect of uncovering solid autism biomarkers. “We have great tools that we’ve never had before,” says psychiatrist Joseph Piven of the University of North Carolina School of Medicine in Chapel Hill. Scientists can assess genes quickly and cheaply, gather sophisticated information about the shape and behavior of the brain, and rely on large organized research collaborations aimed at understanding autism. “That said, I’ve done this long enough to know that people make all kinds of claims: ‘In the next five years or the next 10 years, we’re going to do this,’” Piven says. The reality, he says, is more challenging.
Hahn agrees. “I think it will take quite a bit longer” to find clinically useful biomarkers, he says. “It’s not what parents want to hear. The thing is, this is a very difficult medical disease with many different manifestations.”
Researchers have turned up differences in the brain between people with and without autism, including size and growth patterns, connections between areas and brain cell behavior. But the variability in autism symptoms — and causes — has prompted scientists to look beyond the brain in the search for biomarkers.

“Autism may not be purely a brain disorder,” says neuroscientist Eric Courchesne of the University of California, San Diego. Scientists are looking for important clues to autism in gut microbes, skin cells, the immune system and factors that circulate in the blood.

That was the rationale behind Hahn and colleagues’ experiment, which compared compounds in the blood of 83 children with autism to those of 76 children without the disorder. The researchers focused on a group of molecules implicated in autism. These molecules carry out an intricate series of metabolic reactions called folate-dependent one-carbon metabolism and transsulfuration. Earlier work suggested that these processes are altered in people with autism.

Hahn and colleagues developed a statistical tool that examined the relationships between 24 of these molecules. Instead of looking at the concentration of each individual player, the team wondered if a more global view would help. “Could you find patterns in these that give you a much more predictive pattern than if you look at them one by one?” he asks. The answer, their results showed, was yes.

The statistical tool correctly called 97.6 percent of the children with autism and 96.1 percent of the children without. Just two of 83 children on the autism spectrum were misclassified as being neurotypical, and three of 76 children without autism were misclassified as being autistic. Compared with other methods described in the scientific literature, “the numbers we got out were very, very good,” Hahn says.

Those results are “quite interesting as an example of a blood test,” says neuroscientist Dwight German of the University of Texas Southwestern Medical Center in Dallas. But as a researcher who also works on blood-based biomarkers of autism, German is familiar with a huge caveat: Blood can be fickle. Medications, age and even time of day can influence factors in the blood, he says. “There’s an awful lot of testing you have to do to show that what you’re measuring is related to the disorder and not what they ate for breakfast,” he says.

If these metabolic differences are present just after birth, the blood test could be an extremely early indicator of autism. But much more work needs to be done to validate the new approach, including tests on children younger than 3, Hahn says.

Other issues need to be resolved, too. When tested on 47 siblings of people with autism, children who presumably share genetics and environment with an autistic sibling but who don’t have the disorder themselves, the statistical tool’s performance worsened a bit. The tool incorrectly classified four of the 47 siblings as having autism.

For tougher distinctions between high-risk kids like these, scientists have had success looking back to the brain. Recently, Piven and colleagues studied babies born to parents who already had an autistic child. These “baby sibs” have about a one in five chance of developing autism themselves, a rate higher than that of a child without an autistic sibling. By studying this high-risk group, Piven and colleagues have found brain features that are associated with even more risk.
Researchers had suspected that at some point early in life, brains grow too much in children who will go on to develop autism. Piven and colleagues scanned the brains of 106 babies with older siblings with autism at 6, 12 and 24 months of age. The researchers also included 42 low-risk infants.

At 6 and 12 months of age, the 15 babies who went on to develop autism had more growth in the outer surface of their brains, the cortex, than both the high-risk babies who didn’t develop autism and the low-risk babies, the researchers reported February 16 in Nature. A computer program that analyzed brain growth predicted whether these high-risk infants would go on to develop autism. On a second set of babies, the classification performed well, successfully calling eight out of 10 babies who would go on to develop autism by 24 months of age.

Other work by Piven and colleagues has turned up other brain differences in high-risk babies. Babies who will go on to develop autism have more cerebrospinal fluid on a certain part of the outer layer of their brains than those who don’t develop the disorder. But the results, published online March 6 in Biological Psychiatry, fell short of the predictive power of the brain overgrowth results, Piven says.

Both of these brain scan studies apply only to high-risk babies. It’s not known whether similar tests would work on children without siblings with autism. But it’s possible that these types of detailed findings can help distinguish varieties of autism, and those are distinctions that must be made before scientists can make progress, Piven says. “We call [autism] one thing, but it’s many, many different things. And until we are able to grapple with that in a more meaningful way, it’s sort of an intractable problem.”

Child and adolescent psychiatrist Robert Hendren, of the University of California, San Francisco, envisions a time when this collection of individual disorders collectively called autism are all cataloged in detail, thanks to biomarkers. “We’ll call it autism 23 or autism 14, and we’ll say, ‘We know this is the process that’s going on, and this is how we’re going to personalize our treatments for this person.’”

On the way to that goal, a big breakthrough is unlikely, says Piven. It’s not like the discovery of penicillin for bacterial infections. “You give it, and 10 days later, everything is fine. This isn’t going to be like that.” Even so, the breadth and enthusiasm of the field is promising, he says. “This whole idea of looking at early biomarkers is a new way of thinking, and we have enormous capabilities to make this reality.”

A potential sign of dark matter is looking less convincing in the wake of a new analysis.

High-energy blips of radiation known as gamma rays seem to be streaming from the center of the Milky Way in excess. Some scientists have proposed that dark matter could be the cause of that overabundance. Particles of dark matter — an invisible and unidentified substance that makes up the bulk of the matter in the cosmos — could be annihilating in the center of the galaxy, producing gamma rays (SN Online: 11/4/14).

In the new study, scientists scrutinized the latest data from the Fermi Gamma-ray Space Telescope. At the galaxy’s center, the researchers found more gamma rays than they could explain, they report in a paper posted online April 12 at arXiv.org. But, when the researchers compared the region at the center of the galaxy with control regions away from the galaxy’s center — where dark matter signals wouldn’t be expected — they also found spots with more gamma rays than expected.

“What I see in the control regions looks just like what I see in the galactic center,” says astrophysicist Andrea Albert of Los Alamos National Laboratory in New Mexico, one of the researchers who worked on the analysis. So they can’t claim that dark matter is the cause. “That’s a bummer,” she says.

Premature babies may one day continue developing in an artificial womb, new work with sheep suggests.

A fluid-filled bag that mimics the womb kept premature lambs alive and developing normally for four weeks, researchers report April 25 in Nature Communications. Lambs at a gestational age equivalent to that of a 23- or 24-week-old human fetus had normal lung and brain development after a month in the artificial womb, the researchers discovered. A similar device might be ready for use in premature human babies in three to five years if additional animal tests pan out, study coauthor Alan Flake estimates.
But this is not the science fiction scenario of Brave New World, in which humans were grown entirely in tanks, says Flake, a pediatric and fetal surgeon at the Children’s Hospital of Philadelphia. “I don’t view this as something that’s going to replace mothers.” Technical and biological hurdles would prevent doctors from using an artificial womb to rescue premature babies younger than about 23 weeks, he says.

Researchers have been trying for 60 years to make an artificial womb or artificial placenta, says George Mychaliska, a pediatric and fetal surgeon at the University of Michigan Medical School in Ann Arbor. His own group has been working on an artificial placenta, or what he calls an “extra-corporeal life-support” system for premature babies for a decade. “One month is very impressive, and the data behind that is strong,” Mychaliska says, but adds that what works for lambs might not work as well for human babies.

In the United States, thousands of babies each year are born extremely premature, before 28 weeks of pregnancy. Of those born at the edge of viability, at 23 weeks of gestation, up to about 70 percent die; many of the survivors have lung and other health problems partly caused by efforts to keep them alive. Putting premature babies on ventilators to get oxygen into their bodies has mixed results, Mychaliska says. “The same treatment that is potentially saving their lives is also damaging their lungs.”

Flake and colleagues’ initial efforts to make an artificial womb — including submerging lambs in fluid in a tank — failed. Infection soon set in, killing the animals. This time, the researchers tried to mimic more closely what happens during normal pregnancy. In the new system, a lamb is surgically delivered via cesarean section and placed in a sterile bag filled with an electrolyte fluid. Because the bag is closed, the risk of infection is reduced. Tubes carrying oxygenated blood plug into the lamb’s umbilical cord, and the beating of the fetus’s heart pumps the blood at volumes and pressure comparable to what is normally delivered by the placenta. Other groups have put tubes in the neck and used an external pump to circulate the blood, which may put too much pressure on fetal hearts, causing heart failure, Flake says.

Like a real womb, the artificial one also bathes lambs in the fluid needed for proper lung development. Flake’s team prevents the lambs from taking a breath because even a little air might harm lung development.
Premature babies would have to be delivered surgically and placed immediately into the fluid incubator. That would rule out about 50 percent of extremely premature babies because they are born vaginally, Flake says.

Flake’s version of the device may not be feasible for human babies for several technical reasons, too, Mychaliska says. One barrier is that the system requires a delicate fetal surgery to connect the umbilical cord to the incubator while the baby is still attached to the mother. Few hospitals are equipped to perform such an operation, he says.

Flake acknowledges that several kinks must still be worked out before the artificial womb can be tested on human babies. “We have a lot to learn in terms of its capabilities and its safety,” he says, but his group may soon be ready to begin human clinical trials. “We honestly think it could be as early as two to three years from now — and certainly within five years — that we’ll be applying it to humans.”