Best Citation Awards

For the first time in 20 years, five people have picked up malaria on U.S. soil. On June 26, the U.S. Centers for Disease Control and Prevention issued a health advisory, announcing that over the last two months four people in Sarasota County, Fla, and one person in Cameron County, Texas , had developed the mosquito-borne illness. The new cases mark the first time since 2003 that U.S. residents have contracted malaria after being bitten by a mosquito close to home. All five people received treatment and are improving. Malaria, which is caused by Plasmodium parasites and spread to humans by Anopheles mosquitoes, is not unheard of in the United States. The disease was once prevalent before widespread spraying of the insecticide DDT helped to purge the country of any parasite-infected mosquitoes. By 1951, malaria had been eliminated within U.S. borders. But the disease still circulates in many countries around the world. Globally, there are more than 200 million cases of malaria each...

On the island of Palawan in the Philippines, a cave has yielded reams of ancient artifacts, including thousands of stone tools. No traces of hewn trees or stripped bark or carved meat remain to hint at what the tools may have been used for. But they do bear signs of wear and tear, prehistoric marks from the tasks they once aided. Archaeologist Hermine Xhauflair (center) and colleagues gather on the island of Palawan in the Philippines, where ancient stone tools had been recovered from a cave. Xhauflair spent months living among Indigenous Pala’wan communities, studying how artisans use tools for various tasks in an effort to reveal how the ancient artifacts may have been used. H. Xhauflair To archaeologist Hermine Xhauflair and her colleagues, these marks can serve as fingerprints, identifying the ways past humans used the tools. For help deciphering these fingerprints, Xhauflair’s team turned to the Indigenous Pala’wan people, who live near the site where the artifacts were disc...

You don’t need to touch a tick for it find you, a new study suggests. The blood-sucking parasites may be able to catapult themselves from vegetation to their hosts thanks to static electricity. Mammals, birds and reptiles carry considerable electrostatic charges — equivalent to voltages of hundreds to tens of thousands of volts. And ticks seem to respond to that. Tick nymphs brought close to various objects charged to voltages encountered in nature frequently whoosh across the gap to land on those surfaces, researchers report June 30 in Current Biology . “We know that static electric charges naturally accumulate on many animals, but how the forces generated by these electric charges influence the ecology of said animals has barely been studied,” says Sam England, a biologist at the University of Bristol in England. Ticks are fiendish parasites that feast on blood of vertebrates and are notorious for spreading Lyme disease , Rocky Mountain spotted fever and other potentially debili...

Teenagers in the United States are in crisis. That news got hammered home earlier this year following the release of a nationally representative survey showing that over half of high school girls reported persistent feelings of “sadness or hopelessness” — common words used to screen for depression. Almost a third of teenage boys reported those same feelings. “No one is doing well,” says psychologist Kathleen Ethier. She heads the U.S. Centers for Disease Control and Prevention’s Division of Adolescent and School Health, which has overseen this biennial Youth Risk Behavior Survey since 1991. During the latest round of data collection, in fall 2021, over 17,000 students from 31 states responded to roughly 100 questions related to mental health, suicidal thoughts and behaviors, sexual behavior, substance use and experiences of violence. One chart in particular garnered considerable media attention. From 2011 to 2021, persistent sadness or hopelessness in boys went up 8 percentage poin...

Scientists have made the first image of the Milky Way using neutrinos. The extremely low-mass subatomic particles have no electric charge, and pass easily through gas, dust and even stars on their way from the places where they originate to detectors here on Earth. High-energy neutrinos zip throughout the cosmos, but where they come from is usually a mystery. Now, by combining artificial intelligence and data collected over the course of a decade with the IceCube detector in Antarctica, researchers have found the first evidence of high-energy neutrinos that originated from inside the Milky Way and mapped the particles onto an image of the galaxy’s plane. It’s the first time our galaxy has been imaged with anything other than light. The map includes suggestions of specific high-energy neutrino sources within the Milky Way that might be the remnants of past supernova star explosions, the cores of collapsed supergiant stars or other as-yet-unidentified objects, the team reports in the...

The aptly named resplendent quetzal is prized for its plumage. Golden poison frogs are popular creatures in the pet trade. Pangolin meat is considered a delicacy, and their scales are used in traditional medicine. Those three animals are among the third of all wild vertebrate species that people eat, trade or otherwise use, a new study reveals.  Out of nearly 47,000 vertebrate species around the world, humans exploit about 14,600 , researchers report June 29 in Communications Biology in a comprehensive look at humans’ impact on a vast swathe of wildlife. Some species, like fish trawled from the sea in large quantities for food, are abundant. But human activities are helping push many others of these exploited species toward extinction, marine ecologist Boris Worm and colleagues say. More than half of the vertebrate species that humans exploit — mostly fish and mammals — are killed for food, the team finds. Birds, reptiles and amphibians are primarily targeted for the pet trade....

One of nature’s woody behemoths — the North American snow forest — may soon begin shrinking. The continent’s boreal forest reposes in subarctic latitudes, spanning much of Alaska and Canada. Scientists had previously suggested that its range might shift northward as the climate warms, helping maintain its expansive breadth. But for two decades, the ecosystem’s northern tree line has held fast, while its southerly tree cover has thinned , researchers report June 8 in Nature Communications . Human activities and climate change could push the prodigious forest to contract. “We are about to transform an entire biome on a continental scale,” says environmental scientist Ronny Rotbarth of Wageningen University in the Netherlands. Millions of people — many from Indigenous groups — depend on the boreal forest to live. It’s thought to contain about 25 percent of Earth’s remaining intact forest, and its living flora are estimated to store about 15 billion metric tons of carbon . That exceed...

Beneath the explosions, collisions and other intermittent bangs in the cosmos, scientists suspect a nonstop soundtrack plays, created by ripples in spacetime continually washing through the universe. After more than a decade of searching, scientists may have finally heard that background hum. Several teams of researchers from around the world reported on June 28 the first clear evidence of these gravitational waves. Unlike previously detected gravitational waves, these new ones have ripples that are staggeringly long — on the scale of light-years. Their likely source: innumerable pairs of gargantuan black holes, which churn the spacetime cauldron as they orbit one another. If that hunch is correct, the result would provide the first evidence that pairs of monster black holes, with masses billions of times that of the sun, can coalesce into one. If the gravitational waves are real, and if they truly are a signal of supermassive black hole pairs, “it’s miraculous,” says astrophysicist...

For young squash bugs, a sip full of feces can help the microbes go down. Squash bugs ( Anasa tristis ) are a major agricultural pest, and a bacterial partner called Caballeronia is essential for their survival. To pick up the bacteria, fledgling squash bugs home in on adult poop in the environment , researchers report in the July 10 Current Biology .   If the nymphs don’t find the microbe, they die, says evolutionary biologist and behavioral ecologist Scott Villa of Davidson College in North Carolina. And  Caballeronia  is not plentiful in the environment. So having to fend for themselves is a risky strategy, Villa says. “If it’s so important, why in the heck did they not just put them on a platter for their kids?” Many other insects do just that. Females defecate on their eggs, leaving behind essential bacteria that their young can slurp up. But it was unclear how squash bug nymphs acquired Caballeronia . Figuring it out could lead to ways to interrupt the bacterial...

Sometime between the American Revolution and the California gold rush, the black hole at the Milky Way’s heart woke up. The black hole, called Sagittarius A*, has been quiet and dim since it was discovered in the 1990s. It’s thought to have been mostly quiescent for eons. But roughly 200 years ago, the black hole, as seen from Earth, suddenly brightened as it let out a brief flare of X-rays , researchers report June 21 in Nature . At about 26,000 light-years away, “Sagittarius A* is the closest supermassive black hole to us,” says astronomer Frédéric Marin of the University of Strasbourg in France. “But it’s dormant.” If the black hole is accreting material from its surrounding disk of gas and dust at all now, it’s at a low rate, making the behemoth difficult to observe ( SN: 5/12/22 ). About 30 years ago, astronomers detected bright X-rays from large gas clouds in the galactic center. One explanation was that at some point, Sagittarius A* shot an X-ray pulse into space after eatin...

Keeping secrets is hard. Kids know it. Celebrities know it. National security experts know it, too. And it’s about to get even harder. There’s always someone who wants to get at the juicy details we’d rather keep hidden. Yet at every moment, untold volumes of private information are zipping along internet cables and optical fibers. That information’s privacy relies on encryption, a way to mathematically scramble data to prevent any snoops from deciphering it — even with the help of powerful computers. But the mathematical basis of these techniques is under threat from a foe that has, until recently, seemed hypothetical: quantum computers. In the 1990s, scientists realized that these computers could exploit the weird physics of the minuscule realm of atoms and electrons to perform certain types of calculations out of reach for standard computers. That means that once the quantum machines are powerful enough, they could crack the mathematical padlocks on encrypted data, laying bare t...

Flowers pollinated by honeybees make fewer and lower-quality seeds than flowers visited by other pollinators. That could be because honeybees spend more time buzzing between flowers of the same plant than other pollinators do. As a result, more of the plant’s own pollen is deposited back on itself, leading to more inbred seeds, researchers report June 28 in Proceedings of the Royal Society B . Honeybees command a lot of attention in insect conservation circles, in part because they are important for pollinating our food supply. But the findings emphasize the importance of prioritizing pollinators like wild, native bees, moths and butterflies in conservation efforts too, the researchers say. For the study, ecologists Joshua Kohn and Dillon Travis, both of the University of California, San Diego, painstakingly tracked the pollination of flowers from three native plant species — white sage ( Salvia apiana ), black sage ( Salvia mellifera ) and Phacelia distans — in San Diego County . ...