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    Real Risk to Youth Mental Health Is ‘Addictive Use,’ Not Screen Time Alone, Study Finds

    Researchers found children with highly addictive use of phones, video games or social media were two to three times as likely to have thoughts of suicide or to harm themselves.As Americans scramble to respond to rising rates of suicidal behavior among youth, many policymakers have locked in on an alarming metric: the number of hours a day that American children spend glued to a glowing screen.But a study published on Wednesday in the medical journal JAMA, which followed more than 4,000 children across the country, arrived at a surprising conclusion: Longer screen time at age 10 was not associated with higher rates of suicidal behavior four years later.Instead, the authors found, the children at higher risk for suicidal behaviors were those who told researchers their use of technology had become “addictive” — that they had trouble putting it down, or felt the need to use it more and more. Some children exhibited addictive behavior even if their screen time was relatively low, they said.The researchers found addictive behavior to be very common among children — especially in their use of mobile phones, where nearly half had high addictive use. By age 14, children with high or increasing addictive behavior were two to three times as likely as other children to have thoughts of suicide or to harm themselves, the study found.“This is the first study to identify that addictive use is important, and is actually the root cause, instead of time,” said Yunyu Xiao, an assistant professor of psychiatry and population health sciences at Weill Cornell Medical College and the study’s lead author.Addictive behavior may be more difficult to control during childhood, before the prefrontal cortex, which acts as a brake on impulsivity, is fully developed.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe. More

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    When Humans Learned to Live Everywhere

    About 70,000 years ago in Africa, humans expanded into more extreme environments, a new study finds, setting the stage for our global migration.Geography is one of the things that sets apart modern humans.Our closest living relatives — chimpanzees and bonobos — are confined to a belt of Central African forests. But humans have spread across every continent, even remote islands. Our species can thrive not only in forests, but in grasslands, swamps, deserts and just about every other ecosystem dry land has to offer.In a study published on Wednesday, scientists pinpoint the origin of our extraordinary adaptability: Africa, about 70,000 years ago.That’s when modern humans learned to thrive in more extreme habitats. We’ve been expanding our range ever since. The finding could help resolve a paradox that has puzzled researchers for years.Our species arose in Africa about a million years ago and then departed the continent a number of times over the past few hundred thousand years. But those migrants eventually disappeared, with no descendants.Finally, about 50,000 years ago, one last wave spread out of Africa. All non-Africans can trace their ancestry to this last migration. The new study might explain why the final expansion was so successful.In the new study, Eleanor Scerri, an archaeologist at the Max Planck Institute of Geoanthropology in Jena, Germany, and her colleagues sought to understand what sort of habitats early humans lived in across Africa.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe. More

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    Scientific Study Shows Bogong Moths Use Sky For Migration

    A new study suggests that these Australian insects may be the first invertebrates to use the night sky as a compass during migration.In the summer, the walls of the caves in the Australian Alps are tiled with Bogong moths.Months before, billions of these small, nocturnal insects migrate about 600 miles to this destination — a place they have never visited before. Seeking refuge from the summer heat, they travel across southeast Australia to these cool alpine caves. Then, in the fall, they migrate back to their breeding grounds, where they eventually die.This remarkable journey has long puzzled scientists like Eric Warrant, a neurobiologist at Lund University in Sweden. “How on earth do these moths know where to go?” he said.Now, a study in the journal Nature by Dr. Warrant and his colleagues reveals the details of the insect’s impressive feat, showing that the Bogong moth may be the first invertebrate to use the starry night sky for migration. The findings suggest the insects use a set of internal compasses, one guided by the Earth’s magnetic field and the other by the night sky, to reach their destination.“That an insect brain that is smaller than a grain of rice is able to do this is just remarkable,” said Basil el Jundi, a neuroscientist at the University of Oldenburg in Germany who was not involved in the study.The Australian Bogong moth could fit in the palm of your hand. It has a two-inch-long wingspan, a small set of eyes and a brain that is roughly a tenth of the volume of a grain of rice. Despite their small size, they have played a big role in Australia. Once an important source of food for Indigenous Australians, the insect also holds a strong cultural value because of its impressive migration.Few insects undertake long-distance migration from dispersed breeding grounds to meet in a single, specific destination. The most famous example is the monarch butterfly, which relies on the sun as a visual compass. Like monarchs, Bogong moths use the Earth’s magnetic field for their long journey. They combine the magnetic compass with visual cues or markers, though researchers did not know what these were.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe. More

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    What Happens to Harvard If Trump Successfully Bars Its International Students?

    If President Trump makes good on all his threats, Harvard may lose much of its influence and prestige. It could also become even harder to afford.As President Trump and his team dialed up the pressure on Harvard University last month, threatening to bar its international students, the school issued what was at once a warning and a plea.“Without its international students, Harvard is not Harvard,” school officials wrote in a lawsuit asking a judge to stop the federal government’s actions.It left unsaid what Harvard, if it were no longer Harvard, would become.It’s a scenario that some inside Harvard are beginning to imagine and plan for as the Trump administration lobs attacks from all angles, seeking to cut the university off from both students and billions of dollars in federal funding.Top leaders at Harvard, one of the nation’s oldest universities, including its provost, John F. Manning, a conservative legal scholar who once clerked for the former Supreme Court justice Antonin Scalia, are meeting more frequently to strategize.The school’s board of trustees, the Harvard Corporation, has discussed whether hundreds, if not thousands, of people will need to be laid off.And on 8:30 a.m. Zoom calls once or twice a week, administrative officials meet with senior leaders of Harvard’s undergraduate and graduate schools to share updates about the latest Trump developments, which keep coming rapid-fire.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe. More

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    Gun Deaths of Children Rose in States That Loosened Gun Laws, Study Finds

    Researchers looked at firearm fatalities in the 13 years immediately after the Supreme Court limited local governments’ ability to restrict gun ownership.Firearm deaths of children and teenagers rose significantly in states that enacted more permissive gun laws after the Supreme Court in 2010 limited local governments’ ability to restrict gun ownership, a new study has found.In states that maintained stricter laws, firearm deaths were stable after the ruling, the researchers reported, and in some, they even declined.Guns are the leading cause of death in the United States for people under 18. Dr. Jeremy Faust, an emergency room doctor at Massachusetts General Brigham Hospital in Boston, who was the study’s lead author, said he was dismayed to find that most of the children’s deaths were homicides and suicides.“It’s surprising how few of these are accidents,” Dr. Faust said. “I always thought that a lot of pediatric mortality from guns is that somebody got into the wrong place, and I still think safe storage is important, but it’s mostly homicides and suicides.”John Commerford, executive director of the NRA Institute for Legislative Action, called the study “political propaganda masquerading as scientific research.”The study, published Monday in JAMA Pediatrics, examined the 13-year period after the June 2010 Supreme Court ruling that the Second Amendment, which protects an individual’s right to bear arms, applies to state and local gun-control laws. The decision effectively limited the ability of state and local governments to regulate firearms.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe. More

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    Ancient Trees, Dwindling in the Wild, Thrive on Sacred Ground

    The Putuo hornbeam, a hardy tree that thrives in the damp air by the East China Sea, could be easily overlooked by visitors to the Huiji Temple on an island in the Zhejiang Province.The tree has an unremarkable appearance: spotty bark, small stature and serrated leaves with veins as neatly spaced as notebook lines. But its status is singular. As far as conservationists can tell, no other mature specimen of its species is alive in the wild.The holdout on the island, Mount Putuo, has been there for about two centuries. And according to a study published Wednesday in the journal Current Biology, its setting may have been its salvation.The study found that religious sites in eastern China have become refuges for old, ancient and endangered trees. Since the early years of the Common Era, Buddhist and Taoist temples have sheltered plants that otherwise struggled to find a foothold, including at least eight species that now exist nowhere else on earth.“This form of biodiversity conservation, rooted in cultural and traditional practices, has proven to be remarkably resilient, persisting even in the face of modern civilization and rapid economic development,” said Zhiyao Tang, a professor of ecology at Peking University and one of the study’s authors.The trees survived at religious sites in part because they were planted and cultivated there. The report noted that Buddhism and Taoism emphasize spiritual association with plants and the temples tended to be left undisturbed, shielding the areas from deforestation.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe. More

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    Is Peeing ‘Just in Case’ Bad for Your Bladder Health?

    Q: A urologist recently told me I shouldn’t go to the bathroom “just in case.” Is that true?As children, many of us were encouraged to pee before we left the house or whenever a bathroom was nearby. There was a good reason: using the bathroom “just in case” can help prevent accidents among children prone to “holding it.”Urologists call this practice “convenience” or “proactive” voiding, and people of all ages do it, often before heading out the door or going to sleep.An occasional “just in case” bathroom break won’t do much harm, said Dr. Ariana Smith, a professor of urology at the University of Pennsylvania Perelman School of Medicine. But doing it several times a day, she said, can increase the likelihood of bladder issues by disrupting the natural feedback loop between your bladder and your brain.How does peeing ‘just in case’ affect bladder health?To understand why proactive voiding can be harmful, it helps to know how the bladder works. As your kidneys filter blood to remove waste, they produce urine, which is carried to your bladder. Women can typically hold up to 500 milliliters of urine, or around two cups, in their bladders; men can store 700 milliliters, or nearly three cups.We generally feel the urge to use the bathroom well before we hit that limit, when our bladder contains between 150 and 250 milliliters of liquid. As the bladder fills up, it sends nerve signals to the brain, letting us know it’s time to go.The experts we spoke with said that when you pee “just in case,” your bladder starts alerting your brain too early, before having the standard amount of urine. This disruption can reduce “the volume your bladder can hold over time,” said Siobhan Sutcliffe, an epidemiologist and professor of surgery at Washington University.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe. More

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    Exercise Extends Life for People With Cancer, Study Shows

    The trial, in people treated for colon cancer, showed clear evidence that an exercise program lowered the risk of disease recurrence and death.A first-of-its kind study adds powerful new evidence to research showing that exercise improves cancer survival.The study, a randomized controlled trial of nearly 900 patients at 55 cancer centers in six countries, showed that people who participated in a structured exercise program lived longer without their cancer coming back and without the occurrence of new cancers. Participants in the exercise program had a 37 percent lower risk of dying and a 28 percent lower risk of recurrent or new cancer than those in the control group.Earlier research had suggested such a benefit, but the data were from observational studies that did not prove a causal link, experts said.“We now have definitive evidence that exercise is not just an intervention for quality of life and fitness. This is an intervention that improves survival and should be standard of care,” said Dr. Christopher Booth, the senior author of the paper and a professor of oncology at Queen’s University in Canada.The study, which was published Sunday in the New England Journal of Medicine, looked at patients with Stage III or high-risk Stage II colon cancer who received standard surgery and chemotherapy treatment. Researchers randomly assigned these patients to a control group, which received educational materials promoting physical activity and healthy nutrition, or to a treatment group, which also received support from a “physical activity consultant” — a hybrid of personal trainer and life coach — over three years to increase their aerobic exercise and sustain it. Patients could choose a number of activities, such as biking, jogging, swimming or kayaking, but most opted for a brisk walk of 45 minutes four times a week, Dr. Booth said.Eighty percent of patients in the exercise group remained disease-free after five years, compared to 74 percent of patients in the control group. After eight years, the exercise program had prevented one death for every 14 people who participated in the exercise arm of the study.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe. More