Fish school, insects swarm, and birds fly in murmurations. Now, new research finds that on the most basic level, this kind of group behavior forms a new kind of active matter, called a swirlonic state.
Physical laws such as Newton’s second law of motion — which states that as a force applied to an object increases, its acceleration increases, and that as the object’s mass increases, its acceleration decreases — apply to passive, nonliving matter, ranging from atoms to planets. But much of the matter in the world is active matter and moves under its own, self-directed, force, said Nikolai Brilliantov, a mathematician at Skolkovo Institute of Science and Technology in Russia and the University of Leicester in England. Living things as diverse as bacteria, birds and humans can interact with the forces upon them. There are examples of non-living active matter, too. Nanoparticles known as “Janus particles,” are made up of two sides with different chemical properties. The interactions between the two sides create self-propelled movement.
To explore active matter, Brilliantov and his colleagues used a computer to simulate particles that could self-propel. These particles weren’t consciously interacting with the environment, Brilliantov told Live Science. Rather, they were more akin to simple bacteria or nanoparticles with internal sources of energy, but without information-processing abilities.
This much is clear: The coronavirus is becoming more transmissible. Ever since the virus emerged in China, it has been gaining mutations that help it spread more easily among humans. The Alpha variant, first detected in the United Kingdom last year, is 50 percent more transmissible than the original version, and now the Delta variant, first detected in India, is at least 40 percent more transmissible than Alpha.
What’s less certain, however, is how the virus’s increased transmissibility will affect the pandemic in the United States. Alpha’s arrival prompted worries about a new surge in the spring, but one never came. The proportion of Alpha cases kept going up, but the total number of cases kept going down. People got vaccinated. Alpha became dominant in the U.S. Cases fell even further. The virus had become more biologically transmissible, but it wasn’t being transmitted to more people.
There was one notable and confusing exception: In April, Michigan experienced a spike in cases that experts believe was indeed fueled by Alpha. The fact that the variant had such different consequences for Michigan than it did for the rest of the country shows just how difficult it is to make predictions. Vaccines protect against Alpha, but fears about the variants that slightly erode vaccine protection, Beta and Gamma, have also quieted; neither is causing significant case spikes among the vaccinated. “If there’s ever a time that we needed to be humble, it’s around this issue,” says Michael Osterholm, an infectious-disease epidemiologist at the University of Minnesota.
Carl Schoonover and Andrew Fink are confused. As neuroscientists, they know that the brain must be flexible but not too flexible. It must rewire itself in the face of new experiences, but must also consistently represent the features of the external world. How? The relatively simple explanation found in neuroscience textbooks is that specific groups of neurons reliably fire when their owner smells a rose, sees a sunset or hears a bell. These representations—these patterns of neural firing—presumably stay the same from one moment to the next. But as Schoonover, Fink, and others have found, they sometimes don’t. They change—and to a confusing and unexpected extent.
Schoonover, Fink, and their colleagues from Columbia University allowed mice to sniff the same odors over several days and weeks and recorded the activity of neurons in the rodents’ piriform cortex—a brain region involved in identifying smells. At a given moment, each odor caused a distinctive group of neurons in this region to fire. But as time went on, the makeup of these groups slowly changed. Some neurons stopped responding to the smells; others started. After a month, each group was almost completely different. Put it this way: The neurons that represented the smell of an apple in May and those that represented the same smell in June were as different from each other as those that represent the smells of apples and grass at any one time.
This is, of course, just one study, of one brain region, in mice. But other scientists have shown that the same phenomenon, called representational drift, occurs in a variety of brain regions besides the piriform cortex. Its existence is clear; everything else is a mystery. Schoonover and Fink told me that they don’t know why it happens, what it means, how the brain copes, or how much of the brain behaves in this way. How can animals possibly make any lasting sense of the world if their neural responses to that world are constantly in flux? If such flux is common, “there must be mechanisms in the brain that are undiscovered and even unimagined that allow it to keep up,” Schoonover said. “Scientists are meant to know what’s going on, but in this particular case, we are deeply confused. We expect it to take many years to iron out.”
United Airlines would very much like people to start flying on airplanes again. They stopped during the pandemic—nearly 10 times as many people flew in the United States on Memorial Day weekend in 2019, the Before Times, as on the same three days in 2020. That’s a problem for United, because air travel is, like, United’s whole thing.
That company would also very much like the people who do fly on airplanes to be vaccinated against Covid-19. Not that planes and airports are crucibles of infection! Definitely not, probably. But vaccinations are, let’s agree, a social good. Pretty much everyone wins, except germs.
But United doesn’t want to require vaccination. People get so mad. So earlier this year, corporate bigwigs started brainstorming ideas to encourage people to get vaccinated and also fly United. Their idea: Give everyone who gets their shots a reward. Maybe a few thousand miles’ worth of frequent-flier points? It’s the airline equivalent of a doughnut or a beer. You can have it, as a treat.
But no. “There were a number of us involved who, I would say, lean heavily from the marketing sciences group within United who said, ‘Actually, that’s not the right path,” says Luc Bondar, the vice president of marketing at United and president of the airline’s frequent-flier program, MileagePlus. “I may have crashed an executive meeting to say that there’s a different way. And out of some healthy discussion, we agreed on an approach that’s very aligned with behavioral science.”
For many on Earth, this is a typical day—a nine to five job, some downtime in the evening ready for the day ahead, and two days off at the weekend.
It might come as a surprise to learn that astronauts in space keep a very similar schedule. Just like us mere Earthlings, they work regular hours, with plenty of free time to unwind. They even get weekends off—barring any cause for alarm on the International Space Station (ISS) that requires immediate attention, like dodging space debris.
“It’s important to offer those opportunities for them to decompress,” says Alexandra Whitemire, the Deputy Element Scientist for the Human Factors and Behavioral Performance (HFBP) team at NASA. “They’re living and working in the same tin can, so it’s an important aspect of the mission.”
While it might seem obvious now, this consideration for an astronaut’s work-life balance and mental health was not always the case. Decades of space missions have allowed us to reach this point, and along the way, we’ve encountered and overcome a few challenges. To understand where it all began, we need to take a step back to the dawn of human spaceflight.
At a sleep research symposium in January 2020, Janna Lendner presented findings that hint at a way to look at people’s brain activity for signs of the boundary between wakefulness and unconsciousness. For patients who are comatose or under anesthesia, it can be all-important that physicians make that distinction correctly. Doing so is trickier than it might sound, however, because when someone is in the dreaming state of rapid-eye-movement (REM) sleep, their brain produces the same familiar, smoothly oscillating brain waves as when they are awake.
Lendner argued, though, that the answer isn’t in the regular brain waves, but rather is an aspect of neural activity that scientists might normally ignore: the erratic background noise.
Some researchers seemed incredulous. “They said, ‘So, you’re telling me that there’s, like, information in the noise?’” said Lendner, an anesthesiology resident at the University Medical Center in Tübingen, Germany, who recently completed a postdoc at the University of California, Berkeley. “I said, ‘Yes. Someone’s noise is another one’s signal.’”
.
Olena Shmahalo/Quanta Magazine; noise generated by Thomas Donoghue
In 1974, Stephen Hawking theorized that the universe’s darkest gravitational behemoths, black holes, were not the pitch-black star swallowers astronomers imagined, but they spontaneously emitted light — a phenomenon now dubbed Hawking radiation.
The problem is, no astronomer has ever observed Hawking’s mysterious radiation, and because it is predicted to be very dim, they may never will. This is why scientists today are creating their own black holes.
Researchers at the Technion-Israel Institute of Technology did just that. They created a black hole analog out of a few thousand atoms. They were trying to confirm two of Hawking’s most important predictions, that Hawking radiation arises from nothing and that it does not change in intensity over time, meaning it’s stationary.
“A black hole is supposed to radiate like a black body, which is essentially a warm object that emits a constant infrared radiation,” study co-author Jeff Steinhauer, an associate professor of physics at Technion-Israel Institute of Technology, told Phys.org. “Hawking suggested that black holes are just like regular stars, which radiate a certain type of radiation all the time, constantly. That’s what we wanted to confirm in our study, and we did.”
Film and Writing Festival for Comedy. Showcasing best of comedy short films at the FEEDBACK Film Festival. Plus, showcasing best of comedy novels, short stories, poems, screenplays (TV, short, feature) at the festival performed by professional actors.
Xia Yang / Getty / The Atlantic
Adam Maida / The Atlantic / Shutterstock
:focal(807x594:808x595)/https://public-media.si-cdn.com/filer/e8/f1/e8f1d4f3-de51-4cfc-9d02-971c3a6a315b/iss20_music_meir_saxophone_iss062e150087_web.jpg)
Olena Shmahalo/Quanta Magazine; noise generated by Thomas Donoghue
James' World 2 