WASHINGTON — Vocally warming up puts more dazzle into a bird’s singing for the day, a new test shows, perhaps helping to explain widespread outbursts of birdsong at dawn.

Males of Puerto Rico’s Adelaide’s warblers (Setophaga adelaidae) start trilling through their repertoires of 30 or so songs while it’s still pitch black. Tracking the songs of individual males showed that the order of performance had a strong effect on performance quality, behavioral ecologist David Logue said August 17 at the North American Ornithological Conference. In the early versions of particular songs, males didn’t quickly change pitch as well as they did later, Logue, of the University of Lethbridge in Canada, and colleagues found.

This was the first test for a warm-up effect for daily singing among birds, Logue said. To catch the full stretch of repetitions of songs, Orlando J. Medina (now with the U.S. Fish and Wildlife Service) had to beat the warblers at getting out of the nest in the morning. His recordings of each of nine males’ morning performance for four days allowed computer analysis of how fast a male swept through his trills.

Time of day alone didn’t explain the improvement in singing. So Logue and study coauthor Hannes Schraft, now at San Diego State University, don’t think that factors like increasing light or rising temperatures could explain the improvements. The robust effect of repetition leads Logue to propose what may be a new explanation for big dawn choruses: Males warming up sooner would fare better in competing for mates. Over time, a melodious arms race could have broken out as earlier warm-ups were beaten by even earlier ones.

For chickens, a dip in the sandbox is good hygiene.

Cage-free flocks that “bathe” by flapping around in diatomaceous earth (a fine dust of fossilized algae) and sand prevent serious mite infections, researchers report September 14 in the Journal of Economic Entomology. Major infections of more than 100 mites per bird make hens lay 2 to 4 percent fewer eggs on average. So access to boxes filled with dust, which look like tiny sandboxes, makes sense for birds’ health and for farmers’ wallets.

Dust baths damage mites’ waxy outer coating and kill the pests by drying them out. Scientists already knew dust can help manage mites in badly infested birds but weren’t sure if it could also be preventative.

Researchers from the University of California, Riverside kept cage-free chickens in poultry houses with dust boxes. The scientists infected clean chickens with 20 to 30 mites each, for two consecutive weeks, and then monitored the size of each bird’s infestation. Over six to 10 weeks, each dust-bathing hen carried 100 or fewer mites, on average. When the dust baths were removed, mite populations skyrocketed. The new results point to dust boxes as an alternative to pesticides for cage-free and organic farms, the researchers say.

PASADENA, Calif. — NASA’s Juno spacecraft, in orbit around Jupiter since July 4, is lying low after entering an unexpected “safe mode” early on October 19. A misbehaving valve in the fuel system, not necessarily related to the safe mode, has also led to a delay in a planned engine burn that would have shortened the probe’s orbit.

Juno turned off its science instruments and some other nonessential components this morning at 1:47 a.m. EDT after computers detected some unexpected situation, mission head Scott Bolton reported at an October 19 news conference. The spacecraft was hurtling toward its second close approach to the planet, soaring about 5,000 kilometers from the cloud tops. It has now passed that point and is moving back away from the planet with all science instruments switched off.

The rocket firing was intended to take Juno from a 53.5-day orbit to a 14-day orbit. Juno can stay in its current orbit indefinitely without any impact on the science goals, Bolton said. The goal of the mission — to peer deep beneath Jupiter’s clouds — depends on the close approaches that it makes with every orbit, not how quickly it loops around. “We changed to a 14-day orbit primarily because we wanted the science faster,” he said. “But there’s no requirement to do that.”

For now, mission scientists are trying to figure what happened with the fuel valve and what triggered the safe mode before proceeding with further instructions to the probe.

A protein that can switch shapes and accumulate inside brain cells helps fruit flies form and retrieve memories, a new study finds.

Such shape-shifting is the hallmark move of prions — proteins that can alternate between two forms and aggregate under certain conditions. In fruit flies’ brain cells, clumps of the prionlike protein called Orb2 stores long-lasting memories, report scientists from the Stowers Institute for Medical Research in Kansas City, Mo. Figuring out how the brain forms and calls up memories may ultimately help scientists devise ways to restore that process in people with diseases such as Alzheimer’s.
The new finding, described online November 3 in Current Biology, is “absolutely superb,” says neuroscientist Eric Kandel of Columbia University. “It fills in a lot of missing pieces.”

People possess a version of the Orb2 protein called CPEB, a commonality that suggests memory might work in a similar way in people, Kandel says. It’s not yet known whether people rely on the prion to store long-term memories. “We can’t be sure, but it’s very suggestive,” Kandel says.

When neuroscientist Kausik Si and colleagues used a genetic trick to inactivate Orb2 protein, male flies were worse at remembering rejection. These lovesick males continued to woo a nonreceptive female long past when they should have learned that courtship was futile. In different tests, these flies also had trouble remembering that a certain odor was tied to food.
Si and colleagues found a different protein, JJJ2, that helped Orb2 switch shapes, a change that then allows Orb2 to aggregate. When the researchers boosted levels of JJJ2 protein, a situation that led to more Orb2 accumulation, flies had sharper memories. Usually, flies need about six hours of training to learn that an unreceptive female really doesn’t want to mate. But after a boost of JJJ2, flies learned that courtship was futile in only two hours. What’s more, this memory lasted for days, researchers found.
Kandel, whose work has turned up evidence for CPEB holding memories in sea slugs and mice, says that the new study makes the concept that prions can stabilize memories “quite definitive now.”

JJJ2 didn’t lead to supersmart flies that could learn everything quickly, though. The boost only came for memories that would have been formed anyway, Si says. The change “lowered the threshold for memory formation, but it has not created a situation where now all information that comes in is turned into long-term memory,” he says. “It can only [affect] memory when the conditions are right to produce a memory.”

The Orb2 results come from just long-term memory. “There could be other biochemical processes for other types of memory,” such as immune cells’ memories of former threats, Si says. Still, it’s possible that protein accumulation is one of the fundamental ways memory works.

Self-driving cars promise to transform roadways. There’d be fewer traffic accidents and jams, say proponents, and greater mobility for people who can’t operate a vehicle. The cars could fundamentally change the way we think about getting around.

The technology is already rolling onto American streets: Uber has introduced self-driving cabs in Pittsburgh and is experimenting with self-driving trucks for long-haul commercial deliveries. Google’s prototype vehicles are also roaming the roads. (In all these cases, though, human supervisors are along for the ride.) Automakers like Subaru, Toyota and Tesla are also including features such as automatic braking and guided steering on new cars.
“I don’t think the ‘self-driving car train’ can be stopped,” says Sebastian Thrun, who established and previously led Google’s self-driving car project.

But don’t sell your minivan just yet. Thrun estimates 15 years at least before self-driving cars outnumber conventional cars; others say longer. Technical and scientific experts have weighed in on what big roadblocks remain, and how research can overcome them.
To a computer, a highway on a clear day looks completely different than it does in fog or at dusk. Self-driving cars have to detect road features in all conditions, regardless of weather or lighting. “I’ve seen promising results for rain, but snow is a hard one,” says John Leonard, a roboticist at MIT.
Sensors need to be reliable, compact and reasonably priced — and paired with detailed maps so a vehicle can make sense of what it sees.
Leonard is working with Toyota to help cars respond safely in variable environments, while others are using data from cars’ onboard cameras to create up-to-date maps. “Modern algorithms run on data,” he says. “It’s their fuel.”
Self-driving cars struggle to interpret unusual situations, like a traffic officer waving vehicles through a red light. Simple rule-based programming won’t always work because it’s impossible to code for every scenario in advance, says Missy Cummings, who directs a Duke University robotics lab.
Body language and other contextual clues help people navigate these situations, but it’s challenging for a computer to tell if, for example, a kid is about to dart into the road. The car “has to be able to abstract; that’s what artificial intelligence is all about,” Cummings says.

In a new approach, her team is investigating whether displays on the car can instead alert pedestrians to what the car is going to do. But results suggest walkers ignore the newfangled displays in favor of more old-fashioned cues — say, eyeballing the speed of the car.
Even with fully autonomous vehicles on the horizon, most self-driving cars will be semiautonomous for at least the foreseeable future. But figuring out who has what responsibilities at what time can be tricky. How does the car notify a passenger who has been reading or taking a nap that it’s time to take over a task, and how does the car confirm that the passenger is ready to act?
“In a sense, you are still concentrating on some of the driving, but you are not really driving,” says Chris Janssen, a cognitive scientist at Utrecht University in the Netherlands.

His lab is studying how people direct their attention in these scenarios. One effort uses EEG machines to look at how people’s brains respond to an alert sound when the people are driving versus riding as a passive passenger (as they would in a self-driving car). Janssen is also interested in the best time to deliver instructions and how explicit the instructions should be.

In exploring the ethical questions of self-driving cars, Iyad Rahwan, an MIT cognitive scientist, has confirmed that people are selfish: “People buying these cars, they want cars that prioritize the passenger,” says Rahwan — but they want other people’s cars to protect pedestrians instead (SN Online: 6/23/16).
In an online exercise called the Moral Machine, players choose whom to save in different scenarios. Does it matter if the pedestrian is an elderly woman? What if she is jaywalking? Society will need to decide what rules and regulations should govern self-driving cars. For the technology to catch on, decisions will have to incorporate moral judgments while still enticing consumers to embrace automation.
In 2015, hackers brought a Jeep to a halt on a St. Louis highway by wirelessly accessing its braking and steering via the onboard entertainment system. The demonstration proved that even conventional vehicles have vulnerabilities that, if exploited, could lead to accidents.
Self-driving cars, which would get updates and maps through the cloud, would be at even greater risk. “The more computing permeates into everyday objects, the harder it is going to be to keep track of the vulnerabilities,” says Sean Smith, a computer scientist at Dartmouth College.

And while terrorists might want to crash cars, Smith can imagine other nefarious acts: For instance, hackers could disable someone’s car and hold it for ransom until receiving a digital payment.

WASHINGTON — Before astronomers could discover the expansion of the universe, they had to expand their minds.

When the 20th century began, astronomers not only didn’t know the universe was expanding, they didn’t even care.

“Astronomers in the late 19th century and the very start of the 20th century were very little interested in what we would call the broader universe or its history,” says historian of science Robert Smith of the University of Alberta in Canada.

Some astronomers were interested in the structure of the Milky Way galaxy, the vast collection of stars in which the sun, Earth and known planets reside. “But astronomers played next to no part in the debates at the end of the 19th century about the wider nature of the cosmos,” Smith said in a talk January 28 at a meeting of the American Physical Society. In fact, many scientists believed there was no wider cosmos. Majority opinion held that the Milky Way galaxy, more or less, constituted the entire universe.

“As far as almost all astronomers were concerned, the universe beyond our own limited system of stars was the realm of metaphysics, and working astronomers did not engage in metaphysics,” Smith said.

Astronomers left others to do the wondering.

“The infinite universe beyond our stellar system was territory that professional astronomers really were very happy to leave to mathematicians, physicists, philosophers and some popularizers,” Smith said.

Even among those groups, pre-20th century consensus limited the universe to the Milky Way and its immediate environs. Clues to the contrary were mostly dismissed. Most prominent among those clues was the existence of “spiral nebulae,” fuzzy patches of light clearly distinct from the pointlike stars. Photos of the spiral-shaped blobs suggested that they were solar systems in the making within or around the Milky Way; many people believed the galaxy was home to countless populated planets. Very few people believed that the nebulae were distant replicas of the Milky Way, galaxies in their own right.
In a book published in 1890, for instance, astronomer and respected science popularizer Agnes Clerke wrote that “no competent thinker” believed that nebulae could be galaxies. She retained that view in a later edition published in 1905, Smith said.

But after around 1905, he said, the modern conception of the cosmos began to emerge. Philanthropic contributions in support of new, large telescopes, particularly in the American West, led to observations that slowly transformed the restricted view of a one-galaxy universe into the current commodious cosmos, with billions and billions (technically, gazillions) of galaxies.
At Lick Observatory in California, for instance, James Keeler undertook the task of counting the spiral nebulae. At the time, astronomers knew of a few dozen. Keeler found hundreds of thousands.

“So the spiral nebulae are elevated in importance by Keeler,” Smith said.

By 1912, Vesto Slipher, at Lowell Observatory in Arizona, began reporting measurements of the light emanating from the nebulae, determining how far colors were shifted to the red end of the spectrum, a way to measure how fast the nebulae were flying away from the Earth.

“He would actually start arguing that the spiral nebulae were distant galaxies,” Smith said.

By the 1920s, more and more astronomers took the idea of distant galaxies seriously. Finally Edwin Hubble, at the Mount Wilson Observatory in Southern California, provided the deathblow to the one-galaxy universe. In 1923, his observations of the Andromeda nebula turned up a couple of Cepheid variable stars. Because Cepheids varied in brightness on a regular schedule that depended on their intrinsic brightness, they provided surefire clues to Andromeda’s distance from Earth. Andromeda resided 900,000 light-years away, vastly farther than even the most exaggerated estimates of the Milky Way’s diameter.

Hubble’s use of Cepheids depended on the earlier pioneering work of Henrietta Swan Leavitt at the Harvard observatory. “Her discovery of the period-luminosity relationship in Cepheid variable stars is absolutely fundamental in transforming people’s ideas about first, our own galactic system and second, providing the means to demonstrate that galaxies do in fact exist,” Smith said.

By the end of the 1920s Hubble, combining his distance measurements with velocity measurement made by astronomer Milton Humason, had demonstrated that the farther a nebula was from Earth, the faster it appeared to fly away. That relationship formed the observational basis for the expanding universe. Hubble suggested as much in 1929. Others also realized that the new view of the cosmos implied an expanding universe; one, Georges Lemaître, proposed something very much like today’s Big Bang theory of the universe’s origin.

It took a while, though, for the idea of the universe as the expanding aftermath of a big explosion to open everybody’s mind. In 1935, for instance, the astronomer J.S. Plaskett called Lemaître’s ideas “speculation run wild without a shred of evidence.” Even Hubble was not entirely sure of his own discovery. In 1938, Smith pointed out, Hubble assessed the evidence as consistent with a static universe, while acknowledging that expansion could not be ruled out.

Today’s claims that other big bangs may have happened many times, creating a multitude of cosmic spacetime bubbles known as the multiverse, face similar objections. It’s true that the evidence for a multiverse is not conclusive, just as evidence in the 19th century was not conclusive that spiral nebulae were distant galaxies or “island universes” of their own. But given the historical precedent, it would be silly to say that “no competent thinker” would believe in the possibility of multiple universes today.

The planning for our supernova special issue began months ago. In one early meeting, astronomy writer Christopher Crockett lit up as he told the story of the night supernova 1987A was discovered. The account has all the ingredients of a blockbuster. There’s a struggle (with an observatory door), the element of surprise (an unexpected burst on a photographic plate), disbelief (by our protagonist and a collaborator), a scramble (to figure out how to report the discovery of the supernova), and an action scene that seems impossibly quaint: A driver races to the nearest town 100 kilometers away to send a telegram and alert the world that 166,000 light-years away, a star has exploded.

That story opens Crockett’s feature article commemorating the 30th anniversary of the supernova’s discovery. And we’ve brought it to life in video form as well. Ian Shelton, the telescope operator who spotted 1987A on a three-hour exposure he took of the Large Magellanic Cloud, was kind enough to consult with us for the video. He stars in it in clay form, and his voice makes a few guest appearances too.
Our anniversary coverage of 1987A offers a great summary of the importance of the discoveries that came from the stellar explosion. But Science News has been telling the story of SN 1987A for years. In fact, we began telling its story just days after the discovery. News of the explosion reached the International Astronomical Union on a Tuesday; on Wednesday, the day we went to press, Science News editors slipped a mention of it into that week’s issue. The following week’s issue carried a full story. Dozens more followed. We’ve pulled many of those together in the timeline below, which includes links to PDFs of the original magazine articles. Happy reading!

Leave it to a researcher who studies icy moons in the outer solar system to come up with an out-there scheme to restore vanishing sea ice in the Arctic.

Ice is a good insulator, says Steven Desch, a planetary scientist at Arizona State University in Tempe. That’s why moons such as Jupiter’s Europa and Saturn’s Enceladus, among others, may be able to maintain liquid oceans beneath their thick icy surfaces. On Earth, sea ice is much thinner, but the physics is the same. Ice grows on the bottom surface of floating floes. As the water freezes, it releases heat that must make its way up through the ice before escaping into the air. The thicker the ice, the more heat gets trapped, which slows down ice formation. That’s bad news for the Arctic, where ice helps keep the planet cool but global warming is causing ice to melt faster than it can be replaced.
The answer to making thicker ice more quickly? Suck up near-freezing water from under the ice and pump it directly onto the ice’s surface during the long polar winter. There, the water would freeze more quickly than underneath the ice, where it usually forms.

In theory, Desch says, the pumps used for this top-down approach to ice growth could be driven by technology no more sophisticated than the windmills that have long provided water to farms and ranches on the Great Plains.
Desch and colleagues envision putting such pumps on millions of buoys throughout the Arctic. During winter, each pump would be capable of building an additional layer of sea ice up to 1 meter thick over an area of about 100,000 square meters, or about the size of 15 soccer fields, the researchers estimate in the January issue of Earth’s Future.
It won’t be easy. The Arctic’s harsh environment poses many problems such as frozen pipes. But many of those hitches are being addressed by engineers familiar with developing and maintaining Arctic infrastructure such as small-scale wind turbines and drinking-water systems, Desch says. To build and ship each ice-making buoy to the Arctic would cost about $50,000, he estimates. Over a decade, covering 10 percent of the Arctic Ocean with buoys would cost about $50 billion per year. “It’s a big project, but the point is, it’s not an impossible one,” he argues.

Now is the time to begin detailed designs and build prototypes, Desch says. The Arctic Ocean’s end-of-summer sea ice coverage has decreased, on average, more than 13 percent per decade since 1979. “There’ll be a time, 10 to 15 years from now, when Arctic sea ice will be accelerating to oblivion, and there’ll be political will to do something about climate change,” Desch says. “We need to have this figured out by the time people are ready to do something.”

Walter A. Feibelman of the University of Pittsburgh … has found evidence indicating a fourth ring [of Saturn].… Every 14.78 years, the rings of Saturn can be seen edge-on from Earth, and the past winter marked one of these opportunities.… The thin ring “extends to more than twice the known ring diameter” (or a total of 340,000 miles), and is so faint it cannot be photographed except with a large telescope. — Science News, June 3, 1967

Update
Scientists no longer observe Saturn’s rings only from Earth. Four spacecraft have visited the planet and revealed a complex ring system, with the four previously known rings accompanied by multiple fainter ones. NASA’s Cassini spacecraft, which arrived at the planet in 2004, is now swooping between Saturn and its rings to get the closest views yet (SN Online: 4/27/17). Rings have also been spied around Jupiter, Uranus and Neptune, and in 2012, scientists spotted an exoplanet with giant rings (SN: 3/7/15, p. 5).

When I was pregnant, I spent a lot of time searching for good information about how to keep both my baby and myself healthy after birth. Googling “placenta” and “eat,” I got a list of stories that reached nearly opposite conclusions about the practice.

Some say eating the organ will replenish mom’s nutrients, increase breast milk production and even stave off postpartum depression. Others point out that there are no studies that report these benefits, and placenta eating comes with risks. Scientists and doctors still have a lot of unanswered questions about the safety of the practice.

Here’s one story new mothers considering eating their placenta might want to pay extra attention to: Oregon doctors suspect that contaminated placenta pills may have caused a dangerous infection in a newborn.

Just after birth, this newborn had trouble breathing. Tests revealed a blood infection with Group B Streptococcus, or GBS. These bacteria are found in about a quarter of healthy women’s nether regions and can pose a danger to newborns. The baby probably picked up a GBS infection while passing through the birth canal.

After a round of ampicillin, the baby went home healthy. But five days later, the baby was in trouble again. Doctors at a second hospital found more GBS in the blood. After another round of antibiotics, two types this time, the baby was again sent home.

Doctors at the second hospital learned that three days after the baby had been born, the mother had begun eating six placenta capsules daily. She had hired a company to clean, slice and dehydrate her placenta before grinding it up and putting it into pills. Lab tests found the exact same strain of GBS that had infected the baby in the placenta pills. Genevieve Buser and colleagues published the case details June 30 in the U.S. Centers for Disease Control and Prevention’s Morbidity and Mortality Weekly Report.

Buser, a pediatric infectious disease physician at Providence Health System in Portland, Ore., says the situation represents the first time researchers have turned up harmful bacteria in encapsulated placenta. “But then, I don’t think that anyone has looked.”
The mother’s breast milk tested negative for GBS. GBS can live in both men and women, mainly in the digestive tract, anus, vagina and, occasionally, skin. The placenta pills could have been dosing the mother regularly with the bacteria, boosting bacterial loads on her skin and in her digestive tract. Through touching, those bacteria could have been transferred to the baby.

The fact that the same strain of bacteria was found in the pills and in the baby’s blood led the researchers to suspect that the pills — and the mother — were a likely source of the infection. Still, Buser cautions that the bacteria transfer from pills to mom to baby “can’t be proven in one case study.”

Other sources of infection exist: The mother could have been colonized in a different way, the bacteria could have come from another person, and the placenta pills could have been contaminated after they were made. “This case report raises more questions than it answers,” Buser says. “But that is good and what science and medicine are all about.”

The baby probably picked up the first GBS infection during birth. With all the excitement of a new baby, it’s easy to forget that the placenta also passed through the same birth canal, picking up the same bacteria that live there. And anyway, placentas aren’t sterile. They’re actually home to swarms of various microbes.

Bottom line, Buser says: “This is a human tissue that is not sterilized.” She points out that dehydrating meat, including placenta, isn’t enough to kill bacteria that can make people sick, including forms of E. coli and Salmonella. A snack texturally similar to placenta, dried deer jerky, sickened people in Oregon in 1995 with E. coli O157. In later lab tests, 10 hours of drying failed to kill that bacteria.

Placenta pills (and other placenta recipes) aren’t regulated, which means there’s no way to tell if the product is safe. Nor is there a foolproof way to spot potentially harmful infections in mothers. In this case, the mother tested negative for GBS at 37 weeks of her pregnancy. That was either a bad test or she acquired the infection after it. There were no signs that she — and ultimately, her placenta — was colonized by bacteria that may have been harmful to her baby.

In their report, Buser and her colleagues don’t mince words: “The placenta encapsulation process does not per se eradicate infectious pathogens; thus, placenta capsule ingestion should be avoided.” If a mother still wants to eat her placenta, she ought to tell her care providers, Buser says. That way, they’ll be aware of the possible risks.