Tag Archives: Science

Researchers Want to Restore ‘Good Noise’ in Older Brains

WIRED

Aging people lose variation in brain oxygen levels—a sign of declining cognitive flexibility. A new drug study probes whether that loss can be reversed.

TO EAVESDROP ON a brain, one of the best tools neuroscientists have is the fMRI scan, which helps map blood flow, and therefore the spikes in oxygen that occur whenever a particular brain region is being used. It reveals a noisy world. Blood oxygen levels vary from moment to moment, but those spikes never totally flatten out. “Your brain, even resting, is not going to be completely silent,” says Poortata Lalwani, a PhD student in cognitive neuroscience at the University of Michigan. She imagines the brain, even at its most tranquil, as kind of like a tennis player waiting to return a serve: “He’s not going to be standing still. He’s going to be pacing a little bit, getting ready to hit the backhand.”

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Surprising Limits Discovered in Quest for Optimal Solutions

Quanta Magazine

Algorithms that zero in on solutions to optimization problems are the beating heart of machine reasoning. New results reveal surprising limits.

Our lives are a succession of optimization problems. They occur when we search for the fastest route home from work or attempt to balance cost and quality on a trip to the store, or even when we decide how to spend limited free time before bed.

These scenarios and many others can be represented as a mathematical optimization problem. Making the best decisions is a matter of finding their optimal solutions. And for a world steeped in optimization, two recent results provide both good and bad news.

In a paper posted in August 2020, Amir Ali Ahmadi of Princeton University and his former student, Jeffrey Zhang, who is now at Carnegie Mellon University, established that for some quadratic optimization problems — in which pairs of variables can interact — it’s computationally infeasible to find even locally optimal solutions in a time-efficient manner.

But then, two days later, Zhang and Ahmadi released a second paper with a positive takeaway. They proved that it’s always possible to quickly identify whether a cubic polynomial — which can feature three-way interactions between variables — has a local minimum, and to find it if it does.

The limits are not what their discoverers expected.

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The Long-Lost Tale of an 18th-Century Tsunami, as Told by Trees

WIRED

Local evidence of the cataclysm has literally washed away over the years. But Oregon’s Douglas firs may have recorded clues deep in their tree rings.

ONE NIGHT IN late January 1700, two tectonic plates running along the Pacific Northwest coast released the tension they had accumulated during a centuries-long tête-à-tête. In a tectonic roar, the Juan de Fuca plate slipped past the North American plate, and a roughly 9.0-magnitude earthquake rattled the entire region. The coastline dropped and tsunamis washed over the entire Northwest coast.

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The Squishy, Far-Out New Experiments Headed to the ISS

WIRED

Muscle cells, 3D-printed lunar regolith, and le Blob will soon orbit 250 miles above Earth.

ON TUESDAY, NORTHROP Grumman’s Cygnus cargo spacecraft will haul slime mold, human muscle cells, 3D printer parts for simulated moon rocks, and a mishmash of other exploratory scientific projects to the International Space Station.

The ISS has a long history of hosting experiments designed by scientists eager to explore how rocket launch, microgravity, and handling by astronauts might affect well-established (but Earthly) phenomena. The technologies behind experiments aboard this week’s rocket range from advancing human space exploration to solving health problems on Earth.

A 3D “regolith” printer may end up on a future moon build, and muscle cells grown aboard the ISS may help find drugs to treat age-related muscle loss on Earth. The mesmerizingly complex growth of the slime mold, on the other hand, is largely meant to be educational; it’s aimed at entrancing the hundreds of thousands of students who will be following its progress.

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What Rat Empathy May Reveal About Human Compassion

WIRED

Rats may feel concern when cage mates are trapped. But, like people, they don’t always care enough to help.

AGONY IS CONTAGIOUS. If you drop a thick textbook on your toes, circuits in your brain’s pain center come alive. If you pick it up and accidentally drop it on my toes, hurting me, an overlapping neural neighborhood will light up in your brain again.

“There’s a physiological mechanism for emotional contagion of negative responses like stress and pain and fear,” says Inbal Ben-Ami Bartal, a neuroscientist at Tel-Aviv University in Israel. That’s empathy. Researchers debate to this day whether empathy is a uniquely human ability. But more scientists are finding evidence suggesting it exists widely, particularly in social mammals like rats. For the past decade, Bartal has studied whether—and why—lab rodents might act on that commiseration to help pals in need.

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This Device Could Tune Your Heart—Then Dissolve Away

WIRED

The latest in “electronic medicine” offers an alternative to temporary pacemakers and could help reduce tissue scarring.

THE HEART—THAT PARAGON of natural rhythm—sometimes needs help to stay on beat. Permanent pacemakers, which supply jolts of muscle-contracting current to regulate each thump, can correct chronically irregular hearts, and temporary ones can resolve fleeting dysfunctions that follow open heart surgery. Doctors wire up the heart with electrical leads that pass through the skin, and the muscle tissue envelopes the intruding electrodes like quicksand.

But if the pacemaker is just a temporary precaution, it’s all got to come out. And that’s where it gets tricky.

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The Experimental African Houses That Outsmart Malaria

WIRED

A field test of custom-designed homes proves that when carbon dioxide can flow out, mosquitoes stay out too.

WHEN STEVE LINDSAY first traveled to Gambia in 1985, he met a man living in Tally Ya village whom he remembers as “the professor.” The professor knew how to keep the mosquitoes away.

That’s a big deal for people who live in this small West African country, which serves as the namesake for one of the most deadly bugs on the planet: Anopheles gambiae. “It’s probably the best vector of malaria in the world,” says Lindsay, a public health entomologist at Durham University in the United Kingdom. Malaria kills 384,000 people a year in Africa, 93 percent of whom are under 5 years old. The mosquito exploits human behavior by feeding at night when people are sleeping, transmitting the Plasmodium parasite that causes flu-like symptoms, organ failure, and death. “It’s adapted for getting inside houses and biting people,” says Lindsay.

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The Coelacanth May Live for a Century. That’s Not Great News

WIRED

Scale markings reveal that this weird fish’s lifespan is double what scientists first estimated. That also means they’re closer to extinction than we thought.

AFRICAN COELACANTHS ARE very old. Fossil evidence dates their genesis to around 400 million years ago, and scientists thought they were extinct until 1938, when museum curator Marjorie Courtenay-Latimer noticed a live one in a fisher’s net.

Found off the southeastern coast of Africa, coelacanths also live a long time—scientists have suspected about 50 years. But proving that lifespan has been tough. (Coelacanths are endangered and accustomed to deep waters, so scientists can’t just stick their babies in a tank and start a timer.) Now a French research team examining their scales with polarized light has determined that they can likely live much, much longer. “We were taken aback,” says Bruno Ernande, a marine ecologist who led the study. The new estimated lifespan, he says, “was almost a century.”

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Watch a Drone Swarm Fly Through a Fake Forest Without Crashing

WIRED

Each copter doesn’t just track where the others are. It constantly predicts where they’ll go.

ENRICA SORIA NEEDED soft trees. The mathematical engineer and robotics PhD student from the Swiss Federal Institute of Technology Lausanne, or EPFL, had already built a computer model to simulate the trajectories of five autonomous quadcopters flying through a dense forest without hitting anything. But an errant copter wouldn’t survive a tête-à-tête with a physical tree.

So Soria built a fake forest the size of a bedroom. Motion-capture cameras lined a rail hanging above the space to track the movement of the quadcopters. And for “trees,” Soria settled on a grid of eight green collapsible kids’ play tunnels from Ikea, made of a soft fabric. “Even if the drones crash into them,” Soria recalls thinking, “they won’t break.”

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This Brain-Controlled Robotic Arm Can Twist, Grasp—and Feel

WIRED

Nathan Copeland learned to move a robotic arm with his mind, but it was kind of slow. Then researchers gave him touch feedback.

NATHAN COPELAND WAS 18 years old when he was paralyzed by a car accident in 2004. He lost his ability to move and feel most of his body, although he does retain a bit of sensation in his wrists and a few fingers, and he has some movement in his shoulders. While in the hospital, he joined a registry for experimental research. About six years ago, he got a call: Would you like to join our study?

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