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Scientific American
21-07-2025
- Science
- Scientific American
Optimists Are Alike, but Pessimists Are Unique, Bran Scan Study Suggests
'All happy families are alike; each unhappy family is unhappy in its own way.' This is the first line of Leo Tolstoy's novel Anna Karenina, and it may hold a kernel of truth that goes beyond family dynamics. In a recent study of optimism, neuroscientists found an equivalent principle at play: optimists shared similar patterns of activity in a key brain region when they imagined future events, but each pessimist's brain patterns was unique. The results help neuroscientists understand what distinguishes optimism from pessimism in the brain. This is an important question because optimism is associated with better physical, mental and social health. The results were published on Monday in the Proceedings of the National Academy of Sciences USA. 'We tend to think of imagining the future as a deeply personal, subjective act,' says Kuniaki Yanagisawa, the study's lead author and a psychologist at Kobe University in Japan. 'Our study, however, shows that—especially for optimists—the way our brains do this can be similar' and suggests that such shared cognitive frameworks for imagining the future might explain why we 'click' with some people, he says. Prior studies have shown that optimists have larger social networks and higher acceptance by their peers. Yanagisawa wanted to understand 'whether this social success is just about personality,' he says, 'or if optimists might share a fundamental brain mechanism that makes it easier for them to form social connections.' On supporting science journalism If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today. The researchers scanned participants in a functional magnetic resonance imaging (fMRI) machine while they imagined specific future events happening to either them or their spouse. Some of the events were positive; others were neutral or negative. Afterward the team had the participants take a questionnaire to determine their level of optimism or pessimism. The researchers conducted the study twice, once in a group of 37 participants and again in a group of 50. To analyze the brain scans, the researchers zoomed in on one region that's particularly active while imagining future events: the medial prefrontal cortex, located in the middle of the very front of the brain. They compared patterns of brain activation in each possible pair of participants and used statistical tests to determine how similar the activations were to each other in these pairs. The team found that only pairs consisting of two optimistic participants had similar brain activation; pairs where one or both participants were more pessimistic were dissimilar to each other. The researchers also found that optimistic people showed bigger differences between brain patterns for emotionally positive and negative events than pessimists did. A few prior studies of 'positive' social traits have shown similar results. A 2022 brain scan study showed that people who held a central position in their social network have similar activation patterns to one another—but that less central people had a lot of individual differences, or idiosyncrasies. The same pattern held true in another study of people with low versus high levels of loneliness. Elisa Baek, a social neuroscientist now at the University of Southern California and lead author of those two studies, refers to these results as examples of the ' Anna Karenina principle,' the idea that successful endeavors have similar characteristics but that unsuccessful ones are each different in their own way. 'One intriguing interpretation [of the optimism study], consistent with the Anna Karenina principle, is that there may be many different ways for a person to be pessimistic, while optimistic people tend to converge on a few shared mental models of a hopeful future,' Baek says. Together, these studies 'may point to a more general principle—that being 'on the same page' as others is a foundational mechanism that underlies the experience of social connection.' If there is an Anna Karenina principle at work for positive social traits, what would be causing it? After all, the traits we deem 'positive' vary greatly among different societies, so there's a risk of cultural bias. Yanagisawa thinks that these cultural values could actually be driving the effect—they orient people toward a specific goal that is valued in a society, such as being optimistic or having a lot of social connections, perhaps leading those individuals to behave and think similarly over time. It's also possible that optimism, as measured in this study, is picking up on related traits such as people's level of loneliness or position in a social network. 'These convergent findings raise an important question about the overlap between constructs such as optimism, loneliness and network centrality,' Baek says. 'Because the new study didn't control for loneliness or social network position, and my prior work didn't control for optimism, it is unclear how much these dimensions are overlapping or distinct.' Optimism and pessimism aren't unchanging traits; they tend to shift with age, although the trajectories vary from culture to culture. Nor is optimism an unquestioned good. 'Extreme optimism might not always be a good thing because we might not plan for the future as well as we should,' says Aleea Devitt, a psychologist at the University of Waikato in New Zealand, who studies future thinking. And 'pessimism may be a useful 'positive' trait in some situations; there's evidence that some people can be defensive pessimists, which can actually help them better prepare for the future.'
Yahoo
12-06-2025
- Science
- Yahoo
Animals Expend 76,000 Gigajoules of Energy Sculpting Our Planet Every Year
Earth's surface is a work forever in progress. Boulders tumble down mountain slopes raised by colliding tectonic plates. Glaciers grind the boulders into dust. Wind, rain and rivers carry that dust to the sea, where it becomes sediment. These are among the traditional ways landscapes are known to change. But new research suggests there's a mighty force of nature missing from this picture: animals. In a study published in the Proceedings of the National Academy of Sciences USA, researchers estimate that wild freshwater and terrestrial species, ranging from salmon to elephants, expend 76,000 gigajoules of energy to alter the land around them every year—the equivalent of thousands of extreme floods. Beavers are, of course, famous for their engineering feats. But when it comes to other animals, no matter how extensive their nest building or den digging is, 'the perception has been that they're interesting curiosities but really not that important globally,' says the study's lead author, Gemma L. Harvey, a physical geographer at Queen Mary University of London. 'This paper challenges that.' [Sign up for Today in Science, a free daily newsletter] The study of landform evolution is called geomorphology, and when the changes are caused by animals, we tack on another prefix: zoogeomorphology. As early as 1881, Charles Darwin recognized earthworms' role in soil formation. But it wasn't until 1992 that physical geographer David Butler, now a professor emeritus at Texas State University, coined the term for the effect. He debuted this scientific mouthful that year in a paper on 'the grizzly bear as an erosional agent,' in which he calculated that the bears in Glacier National Park had, over the course of 100 years, moved about 15,000 dump-truck loads of dirt downslope while foraging for food and excavating their dens. 'It made me suspect that if you did this worldwide for hundreds of species, you would come up with astonishing numbers,' he says. The data needed for this kind of investigation weren't available then, but three decades later Harvey's team found enough to analyze 500 species. The researchers learned that trampling hippos create entirely new river channels, and burrowing crayfish widen the banks of existing ones. They found that hulking termite mounds cover an Iceland-size patch of Brazil. 'Those are huge areas,' Harvey says, 'huge amounts of soil being transformed.' Brian Yanites, a geomorphologist at Indiana University Bloomington, who was not involved in this study, notes that such research is often hyperlocalized to 'one type of animal, one specific location or particular landform.' But he says the new work 'is a really elegant way to approach the problem from a macro level.' If anything, the authors think 76,000 gigajoules is probably a wild underestimate; they excluded vast biodiversity hotspots in Africa, South America and Asia because there are few published studies on how living creatures reshape lands in those regions. Although many experts disregard animals as a source of profound landscape change, Butler says, 'I think this study could be a 'Holy crap!' moment for them.'
Scientific American
05-06-2025
- Science
- Scientific American
Velvet Worm Slime Reveals Its Sticky Secrets
The velvet worm, a squishy little predator that looks like the stretch-limo version of a caterpillar, has a whimsical MO: it administers death by Silly String. In the leaf litter of tropical and temperate forests around the world, velvet worms stalk the night on dozens of stubby legs. The pocket-size predator—whose species range from less than half an inch to eight inches long—can barely see, so it bumbles around, hoping to literally bump into an edible bug such as a cricket or a woodlouse. When it finds one, the velvet worm uses nozzles on either side of its face to shoot jets of sticky slime at its victim. 'It happens so fast it's almost like they're sneezing,' says Matthew Harrington, a biochemist at McGill University who has studied velvet worms for a decade. On supporting science journalism If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today. At first, the goo is a watery liquid, but in midair it transforms into jellylike ropes that ensnare the unlucky creature and stick it to the ground. As the prey struggles, the slime forms fibrous threads, and within seconds the substance hardens into a glasslike solid. Scientists have been intrigued by velvet worm slime's adhesive properties for more than a century. (In the 1870s researchers puzzling over what makes it stick tried tasting it. The verdict: bitter.) Recent findings suggest the phase-shifting goo could inspire a new generation of recyclable bioplastics, according to research published by Harrington and his colleagues in the Proceedings of the National Academy of Sciences USA. Previously, the researchers discovered that soaking the hardened fibers in water returned them to their liquid state—and by rubbing the resultant mess between their fingertips, they could get fibers as strong as nylon to re-form. That means 'everything we need to know about making these fibers is encoded in the proteins themselves,' Harrington says. But isolating those proteins is easier said than done, the scientists found. The slime is so sensitive to touch that even standard laboratory techniques such as pipetting can trigger its phase shift. To avoid that sticky situation altogether, the scientists sequenced the RNA of proteins from the slime of velvet worms collected in Barbados, Singapore and Australia. Then they fed the RNA sequences into AlphaFold3, a program that uses artificial intelligence to predict protein shapes. For all three species, it 'spit out this horseshoe shape' rich in the amino acid leucine, Harrington says. Although this structure is novel to materials scientists, it's old hat to evolution. A similar protein called a toll-like receptor is part of an ancient immune system feature found across plants, invertebrates and vertebrates. These receptors sit on the surface of immune cells, binding tightly to pieces of invading microbes and releasing them later. Harrington and his team suggest the horseshoe-shaped protein may use a similar 'host-guest' dynamic to grab onto other proteins in the slime, binding strongly but reversibly to form the powerful fibers. Those are magic words to materials scientists working on developing replacements for plastic that can be broken down easily and re-formed into new shapes. These horseshoe proteins are a significant find, says Yendry Corrales Ureña, a researcher at Costa Rica's National Laboratory of Nanotechnology who studies velvet worm slime but wasn't involved in the study. She adds, however, that these proteins don't account for important properties of the slime such as its toughness or elasticity. 'They are just one piece of the larger puzzle.' Julian Monge Najera, an ecologist at the University of Costa Rica who researches invertebrate evolution, says the fact that three velvet worm species from different continents have the same protein shape in their slime underscores how incredibly ancient velvet worms are and how long ago their chemical R&D must have occurred. The fossil record shows that velvet worms have existed almost exactly as they do now for at least 300 million years, predating both dinosaurs and today's continents. 'If I could go back in a time machine, the velvet worms I would catch in the post-Cambrian period would be identical to the ones in Costa Rica's cloud forests today,' Monge Najera says—phase-shifting slime and all. Harrington and his team are working to purify the horseshoe protein from the slime and confirm its structure via electron microscopy. 'We won't be milking velvet worms for slime to replace plastics,' Harrington says. 'But we hope to copy their chemical tricks.'
Yahoo
28-05-2025
- General
- Yahoo
Cincinnati beware — cicadas pee. And they have 'stronger streams than many mammals'
Millions if not billions of 17-year cicadas have descended on Greater Cincinnati and Southwest Ohio, creating a deafening noise and leaving behind a real mess in their wake. But that mess is not just the nymph shells they leave behind when they emerge from underground. No, cicadas pee, and unlike most insects, they pee a lot. "[C]icadas are able to pee well above their weight class and produce stronger streams than many mammals," writes Scientific American, reporting on a March 2024 paper published in the journal Proceedings of the National Academy of Sciences USA. Now people bothered by the insects have another reason to be disgusted by them. Here's what to know. According to Scientific American, cicadas feed on the fluid in a plant's xylem system. Because that fluid is 95% water, cicadas must consume 300 times their body weight each day to get enough nutrients. And that means they pee a lot. While most insects flick away liquid waste one drop at a time, cicadas pee "in high-speed streams reminiscent of the bathroom habits of mammals," according to the publication. In fact, cicadas can produce stronger streams than some species of small mammals, per Scientific American, including bats and a breed of rodent known as the Wistar rat. Yes. After 17 years underground, Brood XIV is emerging, and it will bring millions if not billions of the noisy insects to Southwest Ohio and a dozen other states this spring. Brood XIV is one of 15 recognized broods of periodical cicadas that emerge every 13 or 17 years, and one of four that appear in the Buckeye State, according to the Ohio Department of Natural Resources. They emerge when the soil temperature reaches 64 degrees, which typically happens in the second half of May. Annual cicadas emerge worldwide each year, but periodical cicadas are found only in eastern North America. They live underground as nymphs for either 13 or 17 years before emerging above ground in massive numbers. Different populations of periodical cicadas are called 'broods' and are numbered with Roman numerals. They are active for three to four weeks as they focus on mating and reproduction, per ODNR. Male periodical cicadas produce a deafening chorus of calls to attract females. Once mated, female cicadas deposit their eggs into the branches of trees and shrubs. Brood XIV cicadas will stretch from northern Georgia to Massachusetts. In Ohio, they will emerge in more than a dozen counties, per ODNR, mostly in Southwest Ohio: Adams Brown Butler Champaign Clermont Clinton Gallia Greene Hamilton Highland Jackson Lawrence Pike Ross Scioto Warren Washington Some of the edge counties will not see as heavy an emergence as others. The cicadas that emerge every 13 or 17 years are different from the ones seen every summer, and it's not just the amount of time between sightings. Dr. Gene Kritsky with Mount St. Joseph University in Cincinnati and founder of Cicada Safari, a group that tracks the emergence of cicadas based on user submissions, told WKRN in Nashville that periodical cicadas emerge in May or June, while annual cicadas show up later, in late June and July, and through the rest of summer. While swarms of noisy insects may be unsettling for some, cicadas are harmless to people and pets, according to ODNR. They are also a valuable food source for native wildlife, including birds, mammals and fish. Egg-laying by female cicadas can cause 'flagging' on trees and shrubs (death of branch tips, from the egg-laying site to the end of the branch), but there is little to no impact on established, otherwise healthy plants, ODNR states. Small or newly planted trees and shrubs are more vulnerable to damage and can be protected by covering them with fine netting for the few weeks that adult cicadas are active. Using pesticides on cicadas is not warranted or recommended. States expecting cicadas this year include Georgia, Kentucky, Maryland, Massachusetts, New Jersey, New York, North Carolina, Ohio, Pennsylvania, South Carolina, Tennessee, Virginia and West Virginia, Gene Kritsky, founder of Cicada Safari, a group that crowdsources and reviews data on cicadas, told USA TODAY. Kentucky and Tennessee probably will get the most cicadas this year, said John Cooley, an ecology and biology associate professor in residence at the University of Connecticut. There will also be large numbers in Georgia, the Carolinas and Pennsylvania, he said. This article originally appeared on Cincinnati Enquirer: Do cicadas pee? Way more than most insects. What to know about Ohio brood
Scientific American
12-05-2025
- Science
- Scientific American
Convergent ‘Cuteness' Is Making Dogs and Cats Look Alike
What do Persian cats, Pekingese dogs and pugs have in common? They all share a dramatically distorted skull, with a flat, round face and a nose pushed up between their eyes. This unnatural morphology is the product of decades or centuries of artificial selection to make our pedigreed animals more closely resemble the intrinsic cuteness of human babies. These breeds have become so morphologically extreme, in fact, that the cats and dogs with these features now have skulls that are more similar to each other than to their own wild ancestors, according to new research in the Proceedings of the National Academy of Sciences USA. 'Wolves and wild cats are quite distinct in skull shape, but by applying [selective breeding] pressure for babylike faces, we've caused short-faced dogs and cats to become very similar to each other,' says senior author Jonathan Losos, an evolutionary biologist at Washington University in St. Louis. 'We've substantially erased 50 million years of evolution.' On supporting science journalism If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today. Dogs and cats with round, flat faces—technically called brachycephalic, from the Greek for 'short head'—show an unusual example of convergent evolution, which occurs when species independently evolve to become similar to each other because they face the same selective pressures. Normally this process is driven by natural selection—for example, birds and bats have both evolved to fly, and distantly related marine animals keep evolving to look like crabs. But in the case of brachycephalic cats and dogs, it's caused by selective breeding to accommodate human preferences for babylike features, such as round, flat faces with high noses. 'These are completely new skull shapes that only came about because of what humans want to see in their companion animals,' says lead author Abby Grace Drake, an evolutionary biologist at Cornell University. Human preferences, however, come with consequences for the brachycephalic animals involved —which could not survive in the wild. 'We're breeding them to look cute, but this has led to very horrible health problems for them,' Drake says. Pets like Persians and pugs often have so much difficulty breathing that they often require corrective surgery, for example, and they frequently suffer from problems with their eyes, teeth and neurological systems. They are also intolerant to heat and exercise because they lack adequate oxygen. Drake, Losos and their co-authors had originally set out to understand the diversity of skull shapes in cats and dogs. They collected skull measurements for 1,810 animals from various sources, including computerized tomography (CT) scans of pets from animal hospitals and specimens from natural history museums. Their sample included 148 domestic cats and 677 domestic dogs, including both purebreds and mixed breeds. Of the dogs, they classified eight breeds as extremely brachycephalic: Boston terrier, Brussels griffon, English bulldog, French bulldog, Japanese chin, Pekingese, pug and shih tzu. For the cats, Persians, Himalayans and Burmese fell into that category. The team also collected data from hundreds of skulls of dozens of wild species representing the majority of the Canidae and Felidae families, to which domestic dogs and cats belong, respectively. To directly compare the animals, the team created three-dimensional models of each skull and marked anatomically similar points on them across species and breeds. The researchers found that skull shapes of brachycephalic animals are unlike anything that has evolved in nature; these breeds—whether cats or dogs—shared more similarities to each other in skull structure than they did to their wild ancestors. Specifically, their palate has been tilted up, which has drastically shrunk their nasal region and restricted their airway as well as the space at the back of their throat. Some Persian cats actually lacked nasal bones entirely. 'People talk about evolution taking millions of years,' Drake says. 'But if you isolate the gene pool with inbreeding and force massive selection pressures, you can produce a remarkable amount of diversity in a short period of time.' While this is fascinating from an evolutionary biology point of view, she and her colleagues emphasize that they do not think it is worth the health consequences for the animals. Losos agrees: 'The welfare of the animals should be the first priority,' he says. One future question for researchers to investigate is the underlying genetics of brachycephalic features, he adds. Some evidence suggests that domestic dogs and cats each have different genes associated with brachycephaly. 'Finding out more about the genetics would certainly be fascinating,' Losos says. Heather Lorimer, a geneticist at Youngstown State University, who was not involved in the research, agrees it would be worthwhile for scientists to investigate the genetics behind brachycephalic features. 'Starting from a careful, descriptive paper like this one, it might be possible to home in on individual developmental control genes that affect specific skull structure elements,' Lorimer says. 'This, in turn, could lead to understanding very specific changes that cause health issues, which could help in breeding choices to improve health and welfare of our pedigreed dogs and cats.' For those looking for a healthy pet that does not contribute to welfare issues, though, Drake has simple advice: get a mixed-breed animal from a shelter.
