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Psychiatrists estimate that several thousand people worldwide, most of them male, wish to get rid of a normal healthy limb; a smaller number actually request its surgical removal. Such radical requests stem from an extremely rare psychiatric illness called body integrity identity disorder (BIID). Other names for the condition include amputee identity disorder and apotemnophilia, meaning “amputation love.” People with BIID report that a particular limb simply does not belong to them and that they suffer because they feel “overcomplete....

Antioxidant vitamins from fruits and vegetables have exhibited cholesterol-fighting properties and beneficial effects for heart function. Now a new study suggests that they could provide protection from a stroke by limiting the amount of inflicted brain damage. Paula C. Bickford of the University of South Florida College of Medicine and her colleagues worked with four groups of rats that followed different diets over the course of four weeks. The control group ate regular rat chow, while animals in the other groups ate chow supplemented with one of the following foods: blueberries, spinach or spirulina, a type of algae....

Climate scientists overwhelmingly agree that climate change is driven by human action, but middle- and high-school teachers seem to have missed that message. The majority of teachers are not aware of this consensus and teach climate change as an ongoing debate in the scientific community. Research published in this week’s Science indicates that although climate change is widely covered by schools throughout the U.S., the novelty of the field combined with surrounding political tensions can leave teachers lost as to what, exactly, they need to teach....

The European Space Agency’s Rosetta spacecraft is doing a little sightseeing on its decadelong cruise through the inner solar system and beyond. Rosetta (launched in 2004) will not reach its primary target, Comet Churyumov–Gerasimenko, until 2014, but in the meantime it has been checking up on some of the denizens of the Asteroid Belt. In 2008 the probe buzzed Asteroid Steins at a distance of just 800 kilometers, and in July of this year Rosetta swung past the much larger Asteroid Lutetia at a distance of 3,160 kilometers....

Fertilizing the ocean with iron could help reduce atmospheric carbon dioxide levels, according to newly released findings of a research cruise. Why? In a word, diatoms. A hunger for iron rules the microscopic sea life of the Southern Ocean surrounding ice-covered Antarctica. Cut off from most continental dirt and dust, the plankton, diatoms and other life that make up the broad bottom of the food chain there can’t get enough iron to grow....

The items below are highlights from the free newsletter, “Smart, useful, science stuff about COVID-19.” To receive newsletter issues daily in your inbox, sign up here. The U.S. Centers for Disease Control (CDC) this week broadened its definition of a “close contact” with an infected person, thereby expanding “the pool of people considered at risk of contracting the novel coronavirus,” writes Lena H. Sun at The Washington Post (10/21/20). To be considered a “close contact,” the 15-minute exposure time for individuals within six feet is now cumulative or total time during a 24-hour period, not sequential, consecutive time....

Childhood adversity is thought by most experts to be bad for cognitive development: for instance, people who grow up in stressful environments tend to score lower on tests of memory and IQ. They also perform worse on tests of impulse inhibition, which in turn predicts success and competence in later life. Now a new study suggests that the picture of how unreliable environments affect cognition is not purely one of harm....

September 11, 2001. In the Twin Towers of New York City’s World Trade Center, intense fires are burning in and above the impact zones struck by hijacked airliners. People evacuating from the 110-story towers realize they are in danger, but they are not in a blind panic. They are not screaming and trampling one another. As they descend the densely packed stairwells, they are waiting in line, taking turns and assisting those who need help....

By Amy Maxmen of Nature magazineEcologists have spent decades trapping and tagging species in the name of understanding biodiversity, but a far easier way may lie just beneath their feet. Soil contains fragments of DNA that can accurately reveal an area’s animal diversity, according to a recent study in Molecular Ecology.“This is the first time anyone has shown that ‘dirt’ DNA not only reflects what species live in an area, but how many [individuals] there are,” says Eske Willerslev, an evolutionary biologist at the University of Copenhagen, Denmark, and a member of the study team....

The human body teems with trillions of microorganisms — a microbial landscape that has attracted roughly $500 million in research spending since 2008. Yet with a few exceptions, such as the use of fecal transplants for treating life- threatening gut infections or inflammatory bowel disease, research on the human microbiome has produced few therapies. That is poised to change as large pharmaceutical companies eye the medical potential of manipulating interactions between humans and the bacteria that live in or on the body....

When you weigh upward of 6,000 kilograms, you tend to make an impression—literally—wherever you go. Such is the case with the African elephant (Loxodonta africana), which, according to new research, is a boon for dozens of other, much tinier species. As elephants walk through the forest or savanna, they leave big footprints behind them—sometimes 30 centimeters deep. These marks then fill with water, creating microhabitats for other forms of life. Researchers at Germany’s University of Koblenz-Landau and other institutions analyzed the contents of 30 footprint pools in Uganda....

In southern California’s Antelope Valley, 24,000 silver-bright mirrors have been positioned to reflect light on two 50-meter-tall towers. And at 11:08 A.M. local time Wednesday, this concentrated light heated steam in those towers to turn a turbine—the first “power towers” in the U.S. to convert the sun’s heat into electricity for commercial use. Dubbed Sierra SunTower, the power plant can produce five megawatts, enough to power roughly 4,000 local homes at full capacity—and provide the modular blueprint for larger plants in California and New Mexico, according to eSolar, the Pasadena start-up behind the power plant....

The Phoenix Lander may have dominated Mars news in recent weeks, but a new study performed here on Earth has turned up a whopper of a finding: The Red Planet seems to have been the victim of a massive hit and run more than four billion years ago. That is the conclusion of researchers who have finally mapped the edges of something known as the Martian hemispheric dichotomy. That feature—in which the crust thickness drops from 30 to about 10 miles (50 to 20 kilometers) over a large area that is the most visible feature on Mars—has been known to astronomers for more than 30 years and was long suspected to be due to an asteroid impact that flung most of the crust out the area....

The mystery emerged in 2015, when nearly 10 percent of the seemingly healthy mangrove forest along northern Australia’s Gulf of Carpentaria suddenly died. Scientists initially blamed this crucial ecosystem’s die-off solely on an unusually strong El Niño, a weather pattern that periodically siphons water away from the western Pacific and lowers local tides. But a new study published in Science Advances reveals that El Niño had a stealthy accomplice: the moon....

Unlike porcupines, dogs are a relatively hands-on (actually, paws-on) species, both with one another and with us. YouTube has numerous videos of dogs essentially saying, “Just keep petting me, please. Yes, that’s it…more.” But this relationship is not one-sided. Many studies find that positive interactions between people and dogs can be beneficial for both species. Increases in β-endorphin (beta-endorphin), oxytocin and dopamine—neurochemicals associated with positive feelings and bonding—have been observed in both dogs and people after enjoyable interactions like petting, play and talking....

The medical sciences can invoke a long and storied tradition of self-experimentation. Typhoid vaccine, cardiac catheterization, even electrodes implanted in the nervous system came about because scientists recruited themselves as their own guinea pigs. One of the most memorable instances happened on April 16, 1943, when Swiss chemist Albert Hofmann inadvertently inhaled or ingested a compound derived from a crop fungus that went by the chemical name of lysergic acid diethylamide, or LSD-25....

Groucho Marx said, “Outside of a dog, a book is a man’s best friend. Inside of a dog it’s too dark to read.” With this wisdom available for decades, the question arises: Why did author Mary Roach stick her arm inside a living cow’s stomach, where it’s too dark to write? Answer: Because that’s the kind of thing Roach does when she’s researching books that will be read outside of a dog....

By Zachary Fagenson MIAMI (Reuters) - Shortly after dusk, three researchers squat on the lawn of a vacant, million-dollar home in a posh Miami suburb, pointing ultrasonic microphones at the darkened mansion. They’re part of the Miami Bat Squad, listening to track down the home of the rare Florida bonneted bat - a critically endangered species that has turned up at a nearby golf course. Scientists know little about the brown, snout-nosed creature, which emits unusual audible noises as it flies and whose population is believed to number only a few hundred....

Hawaii’s big, booming eruptions are born from just under Kilauea volcano’s peak, a new study confirms. Two small reservoirs of molten rock (magma) feed Kilauea’s recent eruptions, according to analysis of chemical tracers from the last 50 years of lava flows. The results suggest that Kilauea volcano also taps a deeper source, because the shallower magma chambers are too tiny to account for all of the lava that has streamed across the island’s surface since 1983....

By Kerri Smith of Nature magazineIn 50 million to 200 million years’ time, all of Earth’s current continents will be pushed together into a single landmass around the North Pole. That is the conclusion of an effort, detailed in the February 9 issue of Nature, to model the slow movements of the continents over the next tens of millions of years. (Scientific American is part of Nature Publishing Group.)A supercontinent last formed 300 million years ago, when all the land masses grouped together on the equator as Pangaea, centered about where West Africa is now....