COLD SPRING HARBOR, N.Y. — Garbled signals from cellular antennas may have grounded the Galápagos cormorant.

Galápagos cormorants (Phalacrocorax harrisi) are the only cormorant species with wings too small to lift the birds’ large bodies off the ground. Broken primary cilia —antennas that cells need to receive key developmental messages — left the cormorants with stunted wings, UCLA evolutionary biologist Alejandro Burga suggested May 12 at the Biology of Genomes meeting.

Burga and colleagues compared DNA of flightless Galápagos cormorants with that of their close relatives, including double-crested cormorants (Phalacrocorax auritus), which have large wings and can fly. The researchers found more than 23,000 differences in more than 12,000 genes. Those changes have occurred within the last 2 million years, a short time by evolutionary standards.
Many of those genes probably have nothing to do with wing size. So Burga and colleagues narrowed down which genes might have had the biggest effect on cormorant evolution using a computer program that predicts whether a change in a gene will affect its function. Genes that have mutations that damage function may have big evolutionary consequences. Of the genes predicted to have altered function, the researchers selected the 3.3 percent that have changed most drastically in Galápagos cormorants.

To determine what these genes do, Burga examined whether any of the human versions of these genes cause problems when they are mutated in people. Eight of the banged-up genes were associated with limb defects caused by faulty primary cilia, hairlike structures that grow from cells. The cilia receive signals important for the development and proper functioning of cells (SN: 11/3/12, p.16). In people, genetic mutations that damage primary cilia lead to a wide variety of diseases, including developmental defects.

Normal versions of those eight genes are necessary for primary cilia to pick up signals sent by an important protein called hedgehog. Those genes are so crucial for normal development that evolution has not allowed them to change much in 300 million years. Three other genes that are mutated in the flightless cormorants affect other aspects of the primary cilia. In people, mutant versions of all 11 cilia genes can cause small limbs, extra fingers and short ribs, Burga said.

It wasn’t clear whether the cilia defects were the primary cause of the birds’ flightlessness. So Burga further narrowed his focus to 10 of the altered Galápagos cormorant genes predicted by the computer program to give the biggest functional and evolutionary disadvantages. Those genes would be the most important wing shrinkers, Burga and his colleagues reasoned.

One of those top 10 candidates is a gene called CUX1. The protein it produces helps turn on other genes. Vertebrates from primitive coelacanths to people have nearly identical versions of the gene. But in flightless cormorants, four amino acids have been lost from the protein, suggesting that it can no longer do its job or does it poorly. In chickens, a defective form of CUX1 can shrink wings. That finding indicates the Galápagos cormorant’s altered form of CUX1 might also make wings smaller because it fails to turn on limb growth genes.
Many researchers would have left the story at that point, says Ludovic Orlando, an evolutionary biologist at the University of Copenhagen. “But they didn’t simply stop there,” Orlando says. “They made an effort to validate their findings. It’s unusual.”

Burga and colleagues wondered whether CUX1 and the primary cilia changes were related. The researchers injected cells used to mimic skeletal development in lab dishes with the normal vertebrate version of CUX1. Activity levels of two cilia genes rose by about 50 percent. That is evidence that CUX1 normally helps to regulate activity of primary cilia genes.

But the Galápagos cormorant version of CUX1 barely budged activity of the cilia genes. It also was not as good at stimulating growth and development of bone cells as the normal version, the researchers found. Those findings strengthen the case that CUX1 and primary cilia together were involved in shrinking the flightless fowl’s wings.

It’s still a mystery why Galápagos cormorants have normal size legs, Burga said.

The cooling effect of pollution may have been exaggerated.

Fossil fuel burning spews sulfuric acid into the air, where it can form airborne particles that seed clouds and cool Earth’s climate. But that’s not the only way these airborne particles can form, three new studies suggest. Tree vapors can turn into cooling airborne particles, too.

The discovery means these particles were more abundant before the Industrial Revolution than previously thought. Climate scientists have therefore overestimated cooling caused by air pollution, says atmospheric chemist Urs Baltensperger, who coauthored the three studies.
Simulating unpolluted air in a cloud chamber, Baltensperger and colleagues created microscopic particles from vapors released by trees. In the real world, cosmic rays whizzing into the atmosphere foster the development of these particles, the researchers propose in the May 26 Nature. Once formed, the particles can grow large enough to form the heart of cloud droplets, the researchers show in a second paper in Nature. After sniffing the air over the Swiss Alps, some of the same researchers report in the May 27 Science the discovery of the particles in the wild.

“These particles don’t just form in the laboratory, but also by Mother Nature,” says Baltensperger, of the Paul Scherrer Institute in Villigen, Switzerland.

Airborne particles, called aerosols, are microscopic bundles of molecules. Some aerosols start fully formed, such as dust and salts from sea spray, while others assemble from molecules in the atmosphere.

Since the 1970s, scientists have suspected that sulfuric acid is a mandatory ingredient for aerosols assembled in the air. Sulfuric acid molecules react with other molecules to form clusters that, if they grow large enough, can become stable. Human activities such as coal burning have boosted sulfuric acid concentrations in the atmosphere, subsequently boosting the abundance of aerosols that seed clouds and reflect sunlight like miniature disco balls. That aerosol boost partially offsets warming from greenhouse gases.

A cloud chamber at the CERN laboratory near Geneva allowed Baltensperger and his collaborators to simulate the atmosphere when sulfuric acid was scarce. The researchers added alpha-pinene, the organic vapor that gives pine trees their characteristic smell, to pristine air and watched for growing aerosols. Previous, though inconclusive, work suggested that the pine vapors might form aerosols.
Alpha-pinene molecules reacted with ozone in the air and formed molecules that reacted and bundled together to form aerosols, the researchers observed. The researchers added an extra layer of realism by using one of CERN’s particle beams to mimic ions from the cosmic rays bombarding Earth’s atmosphere. The “rays” led to the formation of as many as 100 times the number of aerosols. The added ions help stabilize the growing aerosols, the researchers propose.

Further testing showed that the newborn aerosols can rapidly grow from around 2 nanometers wide — roughly the diameter of a DNA helix — to 80 nanometers across, large enough to seed cloud droplets.

At a research station high in the Swiss Alps, researchers observed aerosol formation during atmospheric conditions with low sulfuric acid concentrations and abundant molecules akin to alpha-pinene. The researchers couldn’t confirm the rapid growth seen in the lab, though.

Quantifying the overall climate influence of fossil fuel burning in light of the new discovery will be tricky, says Renyi Zhang, an atmospheric chemist at Texas A&M University in College Station. “Atmospheric processes are complex,” he says. “They had a pure setup, but in reality the atmosphere is loaded with chemicals. It’s hard to draw direct conclusions at this point.”

Radiation from the 23 nuclear tests conducted near Bikini Atoll in the 1940s and ’50s has lingered far longer than previously predicted.

Radioactive material such as cesium-137 currently produces, on average, 184 millirems of radiation per year on Bikini Atoll. And some parts of the island hit 639 millirems per year, researchers report online the week of June 6 in the Proceedings of the National Academy of Sciences. Those measurements, made last year, surpass the 100 millirems per year safety standard set by the United States and the Republic of the Marshall Islands, which controls the island.

Scientists had predicted that, by now, radiation levels would have dropped to 16 to 24 millirems per year. But those estimates came from extrapolating from measurements made in the 1970s. The mismatch probably stems from incorrect assumptions about how rapidly radioactive material washes off the island, proposes study coauthor Emlyn Hughes, a physicist at Columbia University.

Whether the higher radiation levels pose a serious health risk to caretakers who live on the island for part of the year depends on how long they stay on the island and whether the local fruit they eat is safe, Hughes says.

A new technique turns climate-warming carbon emissions to stone. In a test program in Iceland, more than 95 percent of the carbon dioxide injected into basaltic lava rocks mineralized into solid rock within two years. This surprisingly fast transformation quarantined the CO2 from the atmosphere and could ultimately help offset society’s greenhouse gas emissions, scientists report in the June 10 Science.

“It’s working, it’s feasible and it’s fast enough to be a permanent solution for storing CO2 emissions,” says study coauthor Juerg Matter, a geochemist at the University of Southampton in England.
Many existing carbon storage schemes pump CO2 underground, though the approach has been prone to leaks. Targeting basalt, the cooled remains of volcanic outpourings, may offer an advantage over other types of rock. As much as 25 percent of basalt is made up of elements that react with CO2 to form solid carbonate minerals such as limestone, a process that occurs naturally during rock weathering. Since it was thought that this mineralization process takes hundreds to thousands of years in most rock, it seemed far too slow to be useful in combating near-term climate change.
In Iceland, Matter and colleagues blended groundwater with 230 tons of CO2 emissions from a geothermal power plant to create a kind of seltzer water. The researchers then injected the mixture 400 to 800 meters belowground into basaltic rock. After about two years, the team collected samples of the deep rock — and discovered that almost all of the CO2 had mineralized.

At $17 per ton, mineralizing carbon emissions is roughly twice as expensive as existing storage methods, though doesn’t require long-term monitoring to prevent leaks, Matter says. Additionally, the approach only requires water and basalt, he says, and “we have enough basalt globally to take care of all anthropogenic CO2 emissions, theoretically.”

Another research group’s work backs up the new findings. Peter McGrail, a geochemist at the Pacific Northwest National Laboratory in Richland, Wash., and colleagues conducted similar tests using pure CO2 without water. The as-yet-unpublished findings revealed rapid mineralization similar to that reported by Matter and colleagues, McGrail says.

If you want to lock new information into your brain, try working up a sweat four hours after first encountering it.

This precisely timed trick, described June 16 in Current Biology, comes courtesy of 72 people who learned the location of 90 objects on a computer screen. Some of these people then watched relaxing nature videos, while others worked up a sweat on stationary bikes, alternating between hard and easy pedaling for 35 minutes. This workout came either soon after the cram session or four hours later.

Compared with both the couch potatoes and the immediate exercisers, the people who worked out four hours after their learning session better remembered the objects’ locations two days later. The delayed exercisers also had more consistent activity in the brain’s hippocampus, an area important for memory, when they remembered correctly. That consistency indicates that the memories were stronger, Eelco van Dongen of the Donders Institute in the Netherlands and colleagues propose.

The researchers don’t yet know how exercise works its memory magic, but they have a guess. Molecules sparked by aerobic exercise, including the neural messenger dopamine and the protein BDNF, may help solidify memories by reorganizing brain cell connections.

Australia has seen zero mass shootings in the 20 years since it enacted strict gun control laws and a mandatory gun buyback program, researchers report June 22 in JAMA.

Key to this success is probably the reduction in people’s exposure to semiautomatic weapons, Johns Hopkins University health policy researcher Daniel Webster writes in an accompanying editorial.

“Here’s a society that recognized a public safety threat, found it unacceptable, and took measures to address the problem,” Webster says.
In April 1996, a man with two semiautomatic rifles shot and killed 35 people in Tasmania and wounded at least 18 others. Two months after the shooting, known as the Port Arthur massacre, Australia began implementing a comprehensive set of gun regulations, called the National Firearms Agreement.

The NFA is famous for banning semiautomatic long guns (including the ones used by the Port Arthur shooter), but, as Webster points out, it also made buying other guns a lot harder too. People have to document a “genuine need,” pass a safety test, wait a minimum of 28 days, have no restraining orders for violence and demonstrate good moral character, among other restrictions, Webster writes.

“In Australia, they look at someone’s full record and ask, ‘Is this a good idea to let this person have a firearm?’” Webster says. In the United States, “we do pretty much the opposite. The burden is on the government to show that you are too dangerous to have a firearm.”

Australia also initiated a mandatory gun buyback program in 1996, leading to the purchase and destruction of more than 650,000 semiautomatic and pump-action rifles and shotguns.

Simon Chapman of the University of Sydney and colleagues tallied up mass shootings before and after the NFA and analyzed 35 years of mortality data from the Australian Bureau of Statistics.
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From 1979 to 1996, Australia had 13 fatal mass shootings involving five or more victims (not including the shooter), Chapman and colleagues report. From 1997 to May 2016, the country has had none. (Three shootings, however, have killed three or four victims.) Chapman’s team also found that the rate of gun deaths dropped rapidly after 1996 but can’t confirm that this reduction is due to the gun laws.

To celebrate birthdays, my 2- and 4-year-old party animals got vaccinated. Measles, mumps, rubella, chicken pox, diphtheria, tetanus and whooping cough for the older one (thankfully combined into just two shots), and hepatitis A for the younger.

Funnily enough, there were no tears. Just before the shots, we were talking about the tiny bits of harmless germs that would now be inside their bodies, teaching their immune systems how to fight off the harmful germs and keep their bodies healthy. I suspect my girls got caught up in the excitement and forgot to be scared.

As I watched the vaccine needles go in, I was grateful for these medical marvels that clearly save lives. Yet the topic has become fraught for worried parents who want to keep their kids healthy. Celebrities, politicians and even some pediatricians argue that children today get too many vaccines too quickly, with potentially dangerous additives. Those fears have led to reductions in the number of kids who are vaccinated, and along with it, a resurgence of measles and other diseases that were previously kept in check.

Doctors and scientists try to reduce those fears with good, hard data that show vaccines are absolutely some of the safest and most important tools we have to keep children healthy. (Here’s a handy list of papers if you’d like to dig deeper.) A study published online March 10 in Pediatrics shows a particularly compelling piece of data on the impact of vaccines.

In 2000, doctors began using a vaccine called PCV7, which protected children against seven kinds of Streptococcus pneumoniae bacteria. PCV13 came along in 2010, adding six more types of bacteria to the protective roster. These bacteria can cause many different illnesses such as ear infections, meningitis and blood infections called bacteremia. In young children, these infections can sometimes be quite dangerous (and hard to diagnose).
Medical records that span these pre- and post-vaccine time periods, kept by Kaiser Permanente Northern California, offered a chance to see these pneumococcal vaccinations in action. Before the vaccine existed, 74.5 of 100,000 kids ages 3 months to 36 months got pneumococcal bacteremia. After PCV13, that number had plummeted to 3.5 per 100,000. That’s a 95.3 percent reduction.

This plunge is striking, says study coauthor Tara Greenhow, a pediatric infectious disease specialist at Kaiser Permanente Northern California in San Francisco. Along with earlier results, the new study shows that pneumococcal vaccines are highly effective, she says.

As you check out the graph, pay attention to the data points you don’t see. Those are the babies and toddlers who didn’t end up sick, thanks to a vaccine.

Pluto may get its smattering of red spots from the fallout of its hazy blue skies, researchers say.

Haze particles from the dwarf planet’s atmosphere settle onto all of Pluto’s surfaces. But some regions may become redder and darker than others because parts of the atmosphere collapse, exposing those spots to more surface-darkening radiation from space, researchers report March 22 at the Lunar and Planetary Science Conference in The Woodlands, Texas.

“The atmospheric haze on Pluto was a spectacular surprise,” says NASA New Horizons mission scientist Andrew Cheng, a physicist at Johns Hopkins University. When the New Horizons spacecraft flew past Pluto in 2015, scientists weren’t expecting to see haze reaching at least 200 kilometers above the dwarf planet’s surface; nor were they expecting to see the haze divided into about 20 delicate and distinct layers (SN Online: 10/15/15).
These discoveries led researchers to suspect that the layers formed as a result of weak winds blowing across Pluto’s surface and over its mountains. Cheng and colleagues describe how the winds would shape the haze layers in a paper accepted in Icarus and posted online February 24 at arXiv.org. The team also explains how the atmosphere may affect the color of the dwarf planet’s surface features.
“Haze particles continually fall out onto the surface and rapidly build up,” Cheng says. This process should effectively “paint” the entire surface a uniform color — but Pluto isn’t a single color. It has strikingly bright and dark terrains, with some of the highest contrast found in the solar system. These dark and light regions form because portions of Pluto’s atmosphere periodically collapse, with air freezing and falling onto the dwarf planet’s surface, he and colleagues suggest.
When a section of the atmosphere collapses, parts of the surface are exposed directly to radiation from space, which would darken the surface particles there, Cheng explains. The richness of the reds, the team says, cannot be explained without some kind of collapse of the atmosphere, which does eventually redevelop.

Observations from NASA’s Kepler spacecraft also support the idea that Pluto’s atmosphere collapses. In fact, as Pluto moves away from the sun, most, if not all, of its atmosphere may collapse onto the dwarf planet’s surface, reported Carey Lisse, also of Johns Hopkins University, at the conference.
Exactly how much of Pluto’s atmosphere freezes out during its year, which lasts for 248 Earth years, isn’t clear. But that is currently being monitored, says Timothy Dowling, an atmospheric scientist at the University of Louisville in Kentucky, who was not involved in the new work. Pluto, he notes, won’t complete the first lap that humans have watched it make around the sun until 2178.

The moon’s origin story does not add up. Most scientists think that the moon formed in the earliest days of the solar system, around 4.5 billion years ago, when a Mars-sized protoplanet called Theia whacked into the young Earth. The collision sent debris from both worlds hurling into orbit, where the rubble eventually mingled and combined to form the moon.

If that happened, scientists expect that Theia’s contribution would give the moon a different composition from Earth’s. Yet studies of lunar rocks show that Earth and its moon are compositionally identical. That fact throws a wrench into the planet-on-planet impact narrative.
Researchers have been exploring other scenarios. Maybe the Theia impact never happened (there’s no direct evidence that the budding planet ever existed). Instead of a single colossal collision, scientists have proposed that a string of impacts created miniature moons largely from terrestrial material. Those mini moons merged over time to form one big moon.

“Multiple impacts just make more sense,” says planetary scientist Raluca Rufu of the Weizmann Institute of Science in Rehovot, Israel. “You don’t need this one special impactor to form the moon.”

But Theia shouldn’t be left on the cutting room floor just yet. Earth and Theia were built largely from the same kind of material, new research suggests, and so had similar compositions. There is no sign of “other” material on the moon, this perspective holds, because nothing about Theia was different.

“I’m absolutely on the fence between these two opposing ideas,” says UCLA cosmochemist Edward Young. Determining which story is correct is going to take more research. But the answer will offer profound insights into the evolution of the early solar system, Young says.
The moon is an oddball. Most of the solar system’s moons are way out among the gas giant planets. The only other terrestrial planet with orbiting satellites is Mars. Its moons, Phobos and Deimos, are small, and the prevailing explanation says they were probably asteroids captured by the Red Planet’s gravity. Earth’s moon is too big for that scenario. If the moon had come in from elsewhere, asteroid-like, it would probably have crashed into Earth or pulled off into space. An alternate explanation dating from the 1800s suggested that moon-forming material flew off of a fast-spinning young Earth like children tossed from an out-of-control merry-go-round. That idea fell out of favor, though, when scientists calculated that the spin speeds required were impossibly fast.
In the mid-1970s, planetary scientists proposed the giant-impact hypothesis and the mysterious planet-sized impactor (named Theia in 2000 for the Greek deity who was mother of the moon goddess Selene). The notion made sense given that the early solar system was like a game of cosmic billiards, with giant space rocks frequently colliding.

A 2001 study of lunar rocks collected during the Apollo missions cast doubt on the giant-impact hypothesis. The research showed that the Earth and moon had surprising similarities. To determine a rock’s origin, scientists measure the relative abundance of oxygen isotopes, which act something like finger-prints at a crime scene. Rocks from Earth and its moon, the scientists found, had seemingly identical mixes of oxygen isotopes. That didn’t make sense if much of the moon’s material came from Theia, not Earth. Using impact simulations, Rufu and colleagues recently estimated that the chance of a Theia collision yielding an Earthlike lunar composition is very slim.

Studies of other elements in Apollo rocks, such as titanium and zirconium, also suggest that the Earth and moon originated from the same material. Young and colleagues recently repeated the oxygen isotope measurements with the latest techniques, hunting for even the slightest difference between Earth and the moon. In January 2016, the team published the results in Science. “We measured the oxygen to the highest precision available,” Young says, “and, gosh, the Earth and moon still look identical.”
Some scientists have built simulations of a giant Theia impact that fashion a moon made mostly from terrestrial material. But the scenarios struggle to match the modern positions and movements of the Earth-moon system.

It’s time to think outside the giant-impact box, some scientists argue. Not one but many impacts contributed to the moon’s formation, Rufu and colleagues proposed January 9 in Nature Geoscience. The moon, they say, has an Earthlike composition because most of the material flung into orbit from these impacts came from Earth.

Mini-moon merger
The multi-impact hypothesis was first put forward in 1989, though scientists at the time didn’t have the computer power to run the simulations that could support it. Rufu and colleagues recently revisited the proposal with computer simulations of multiple impactors, each about a hundredth to a tenth of Earth’s mass, smacking into the early Earth.

Any impactors that were direct hits would have transferred lots of energy into the Earth, excavating terrestrial material into space. Debris from each impact combined over centuries to form a small moon, the simulations show. As more impacts rocked Earth over tens of millions of years, more moons formed. Gravity pulled the moons together, combining them. Over roughly 100 million years, according to this scenario, around 20 mini moons ultimately merged to form one mighty moon (SN Online: 1/9/17).
The multimoon explanation yields the right lunar mix in simulations roughly 20 percent of the time, better than the 1 to 2 percent for the giant-impact hypothesis, the researchers note. “The biggest takeaway is that you cannot explain everything with one shot,” Rufu says.

Planetary scientist Robin Canup finds the scenario convincing. “To me, this appears to be a real contender alongside the one big impactor hypothesis,” says Canup, of the Southwest Research Institute in Boulder, Colo.

Don’t discount Theia
But the Theia hypothesis has recently found fresh support. The odds of Theia resembling Earth’s composition enough to yield an Earthlike moon may be a lot higher than originally thought, new chemical analyses suggest. Most of the material that makes up Earth came from the same source as a type of meteorite called enstatite chondrites, planetary scientist Nicolas Dauphas of the University of Chicago reported January 26 in Nature.

Just as with oxygen, the isotopic mix of various other elements in Earth’s rocks serves as a fingerprint of the rocks’ origins. Some of these elements are iron-lovers, such as ruthenium, which quickly sink toward Earth’s iron-rich core (SN: 8/6/16, p. 22). Any ruthenium found close to Earth’s surface, in the mantle, probably arrived late in Earth’s development. Iron-indifferent elements like calcium and titanium don’t sink to the core; they stay in the mantle. Their isotopes record what went into Earth’s assembly over a much longer period of time. By looking at the iron-lovers and iron-indifferent elements together, Dauphas created a timeline of what types of space rocks added to Earth’s mass and when.
A mix of different rocks, including some resembling enstatite chondrite meteorites, supplied the first 60 percent of Earth’s mass, Dauphas says. The remaining balance came almost exclusively from the meteorites’ precursors. In total, around three-quarters of Earth’s mass came from the same material as enstatite chondrites, Dauphas estimates. If Theia formed at around the same distance from the sun as Earth, then it primarily formed from the same material, and consequently had a similar isotopic composition. So if the moon formed largely from Theia, it makes sense that lunar rocks would have a similar composition to Earth, too.
“Most of the problem is solved, in my opinion, if you admit that the great impactor’s material was no different than that of the [early] Earth,” says cosmochemist Marc Javoy at the Institute of Earth Physics of Paris. “It’s the simplest hypothesis” and would mean that the material gobbled up by budding planets in the inner solar system was fairly uniform in composition, offering insight into the arrangement of material that built the solar system.

The notion that Earth is made from the same material as enstatite chondrites “doesn’t make many people happy,” says geochemist Richard Carlson of the Carnegie Institution for Science in Washington, D.C. The isotopes in Earth’s mantle and the meteorites may match, but the relative abundance of the elements themselves do not, Carlson wrote in a commentary in the Jan. 26 Nature. An additional step in the process is needed to explain this compositional mismatch, he says, such as some of the element silicon getting stashed away in Earth’s core.

“What we have now are a lot of new ideas, and now we need to test them,” says Sarah Stewart, a planetary scientist at the University of California, Davis.

One recently proposed test for the moon’s formation is based on temperature, though it seems to be consistent with both origin stories. A new study comparing the moon’s chemistry with glass forged by a nuclear blast suggests that temperatures during or just after the moon’s inception reached a sizzling 1400° Celsius. That means any plausible moon-forming scenario must involve such high temperatures, researchers reported February 8 in Science Advances.
High heat causes rocks to leach light isotopes of zinc. The green-tinged glass forged in the heat of the 1945 Trinity nuclear test in New Mexico lack light isotopes of zinc, says study coauthor and geologist James Day of the Scripps Institution of Oceanography in La Jolla, Calif. The same goes for lunar rocks. Such high temperatures during or just after the moon’s formation fit with the giant-impact hypothesis, he says. But Rufu calculates that her multi-impact hypothesis also yields high enough temperatures.
So maybe temperature can’t resolve the debate, but probing the composition of Earth and the moon’s deep interiors could prove the mini-moon explanation right, says Rufu. Without a single giant collision, the interiors of the two worlds may not have been well mixed, she predicts. Dauphas says that measuring the compositions of other planets could lend credence to his Earthlike Theia proposal. Mercury and Venus would also have formed largely from the same kind of material as Earth and therefore also have Earthlike compositions, he says. Future studies of the solar system’s inhabitants could confirm or rule out these predictions, but that will require a new chapter of exploration.

To halt the misuse of opioids, it may help to slash the number of pills prescribed, a new study suggests.

Five months after the implementation of new opioid prescription guidelines at a University of Michigan hospital, roughly 7,000 fewer pills went home with patients — a drop that might reduce the risk of accessible pills leading to substance abuse. But the opioid reduction didn’t leave patients who had undergone a routine surgery with more pain, the team reports online December 6 in JAMA Surgery.
“The decline in opioid volume after the intervention was dramatic,” says physician Mark Bicket of Johns Hopkins University School of Medicine, who was not involved in the study.

Around 50 percent of people who misuse opioids get the drugs from a friend or relative for free, while 22 percent obtain them from a doctor, according to the U.S. Department of Health and Human Services. Michael Englesbe, a surgeon at the University of Michigan in Ann Arbor, says that part of doing a better job of managing patients’ pain “will be preventing chronic opioid use after surgical care and making sure fewer pills get into the community.”

Englesbe and colleagues looked at 170 people who had a minimally invasive surgery to remove their gallbladders at the University of Michigan hospital from 2015 to 2016. All had received a prescription for opioids. Of those patients, 100 completed a survey detailing how much of the prescription they took, whether they also used a common painkiller such as ibuprofen or acetaminophen, and how they rated their pain during the first week after surgery.

The 170 individuals typically received a prescription equivalent to 40 to 60 tablets, each containing 5 milligrams of hydrocodone. Seven of the 170 patients requested an opioid prescription refill. The 100 patients who completed the survey used very little of their prescriptions, usually somewhere from one to 12 pills. And their average pain score on a scale of zero (no pain) to 10 (the worst pain imaginable) was five.
Based on this information, guidelines for opioid prescriptions following the same type of surgery were implemented at the hospital in November of 2016. The researchers recommended prescriptions of 15 opioid pills, plus the use of common painkillers.

In the five months after the guidelines went into effect, 200 patients had the gallbladder surgery. Five of those patients asked for an opioid prescription refill. Eighty-six of the patients filled out the survey and reported that they used even less of their prescriptions — from zero to nine pills — than the pre-guidelines survey group. These patients also noted the same average pain score as the previously surveyed group and similar common painkiller use.

The study demonstrates “a relatively simple intervention at the institutional level with promising results,” Bicket says. “Patients receive opioid prescriptions within a health care system, so it makes sense to focus on getting our systems to work better in reducing the unnecessary supply of opioids after surgery.”

Along with this gallbladder procedure, Englesbe and colleagues have developed opioid prescribing recommendations for other routine surgeries, such as appendix removal and hernia repair, for the state of Michigan.