DiscoverSeptember/October 2019的目錄

BIRDS OF A FEATHER Despite a spirograph-like appearance, these loops and twists actually represent the flight paths and wingbeats of a flock of jackdaws, members of the wily crow family that mate for life. Researchers had thought that each member of a flock flew independently of their mates, allowing them to pay close attention to others and rapidly communicate to evade predators. But new research in Cornwall, England, found that jackdaws stick with their mates as they fly, a sweet but ultimately dangerous act since it distracts the pair from the rest of the flock’s actions and sing of howlows the overall flow of information. This newly discovered behavior could change our understand avian flight patterns evolved.…

IT WAS HIGH UP ON THE PLATEAU OF TIBET in Nepal in 2015 — a six-day mule trek away from civilization — when Geraldine Werhahn took a photo so iconic that it now graces the country’s 5 rupee note. Werhahn, a zoology graduate student at the University of Oxford, had finally spotted a wild yak. Yaks are nothing short of legends in Nepal. The domesticated variety of the bovine, which is smaller than its wild cousin, is a cornerstone of the country’s agriculture-based economy and is featured on the old 5 rupee note. But no one had spotted a wild yak in Nepal in nearly 55 years, despite a 2013 expedition for that exact purpose, led by the Nepalese non-governmental organization Friends of Nature. During an excursion in search of…

IN 2009, DISCOVER reported that University of Washington physiologist Chet Moritz had made serious strides toward curing paralysis. He and his colleagues figured out a way to record and transfer signals from a macaque’s brain to its paralyzed arm, bypassing its injured nerves, and allowing the monkey to control its limb once more. Challenges remained, but Moritz told Discover he thought advances in these technologies could provide an answer to paralysis in as little as 10 years. Well, it’s 2019 — was he right? Yes and no. Three different research groups have recently announced that they’ve achieved the first independent walking steps taken by patients with spinal cord injuries. But the groups, all unaffiliated with Moritz, didn’t do it his way. Instead, the teams figured out how to coax the…

Hidden amid these colorful swirls are a bunch of jerks that could mess with your phone’s maps app. But thanks to this vivid computer simulation of our planet’s core, published recently in Nature Geoscience, researchers are finally able to model and explain these so-called geomagnetic jerks. The long-mysterious phenomena, discovered in 1978, can introduce errors in technologies tied to Earth’s magnetic field, including satellites and power grids. Just beyond Earth’s solid inner core (center), the circulation of molten metals shapes our planet’s magnetic field. Over centuries, a slow and steady transfer of energy through convection — hotter materials (red) rising as cooler materials (blue) sink — gradually shifts the field (orange). However, sometimes sudden, unpredictable changes occur in a fraction of the time. These are the jerks. Using the new…

TENGs can already harness static electricity to power small devices, but perhaps one day they could do more. These ball-shaped TENGs, designed in Wang’s lab, generate electricity by rolling a silicone rubber ball along the inside of a plastic shell. The rubbing of different materials creates a charge imbalance within them; attaching electrodes to the different sides allows current to flow from one to the other, balancing their charges.…

The incessant “eep, eep, eep” of hundreds of hungry flamingo chicks bounces off the concrete walls of a feeding room at the Southern African Foundation for the Conservation of Coastal Birds (SANCCOB) wildlife sanctuary in Cape Town, South Africa. Teri Grendzinski reaches into a pen and plucks out a fluffy, pale gray chick. The bird opens its mouth eagerly as her syringe squirts out a kind of warm shrimp milkshake. It’s noisy, hot work. To keep the orphans warm, their rooms are heated to a balmy 86 degrees Fahrenheit. And there are so many birds, volunteers have to feed them around the clock in shifts, mixing endless shakes and bringing in a new group of chicks as soon as one is finished. Scenes like this were common during the flamingo…

Humans have a trash problem. For years, researchers have warned that our wasteful ways have been clogging up the planet, even in places where we aren’t, like remote islands. Now, a new study in Scientific Reports says the problem is even worse than we thought. Previous surveys of debris in these isolated areas have mostly focused on what was visible at the surface. However, the new research, which focused on both inhabited and uninhabited islands that make up Australia’s Cocos (Keeling) Islands, reports that the problem goes deeper than that — literally. 414 million pieces Estimated man-made debris on Cocos (Keeling) Islands 262 U.S. tons Weight of estimated debris 93% Percentage of trash up to 4 inches below the surface (60% of this is micro-debris less than a quarter-inch in…

39,773: how many Americans lost their lives to firearms in 2017. 1.625 million: the number of Americans who have died from gunfire since 1968 — more than the accumulated American deaths from all wars since the country’s founding more than 200 years ago. These are numbers that everyone agrees on. From here, nearly everything else that can be said about gun violence in the U.S. elicits a partisan response. It doesn’t have to be this way. A purely scientific approach may hold the key to making progress toward reducing injuries and fatalities. A growing chorus of researchers wants to study gun violence in the U.S. as a public health issue, similar to the way they have tracked automobile or workplace safety for decades. Though limited by largely political obstacles around…

Research on TriboElectric NanoGenerators (TENGs), which exploit everyday static electricity to power devices, extends beyond the lab of Zhong Lin Wang. “A lot of research groups worldwide, from academics and industry, are rushing to TENG research for self-powered internet-of-things sensors, electronics and healthcare applications,” says electrical engineer Sang-Woo Kim, a professor at South Korea’s Sungkyunkwan University. In response to Wang’s initial research, Kim’s group was the next to start pursuing TENGs. In 2015, they introduced a material that uses triboelectric threads — clothing made from this material can charge a smart watch after only a few hours of being worn. In 2017, they followed up with a stretchable TENG-based fabric. The paper, published in ACS Nano, discussed the relative power-generating merits of knitted and woven textiles. Ramakrishna Podila of Clemson…

Weather happens in the lower level of our atmosphere, called the troposphere. There, rising warm air (an updraft) cools as it gets higher, causing the moisture it holds to condense into droplets — rain. Cool air sinks (a downdraft) and spreads out as it hits the ground, creating the wind you often feel as a storm approaches. This warm-cold clash also happens when pockets of different temperatures meet, called a front. Hail Forms when ice pellets move up and down in the warm and cold drafts, growing larger as they gain layers of ice. Sleet Rain that freezes into ice pellets while falling through cold air. Snow Forms from ice crystals that merge in clouds. Freezing Rain Rain that freezes when it hits the ground or other surfaces. Rain and…

GIANT SQUID are tough to find because they’re rare and live deep in the ocean. Similarly, if a giant planet lives deep in the solar system, telescopes will have a hard time spotting it. But despite no physical evidence, some scientists still believe such a hypothetical world lurks about 56 billion miles from the sun. The presence of this world, up to 10 times as massive as Earth and known as “Planet Nine,” would solve the orbital mysteries of other way-out objects. But is this “planet” just a gravitational illusion? In Science Smackdown, we let experts argue the evidence. The Claim PLANET NINE LIVES Centered about 3.7 billion miles from the sun, the Kuiper Belt — a doughnut of icy rocks and rocky ice past Neptune’s orbit — serves as…

As the students calmly watched from their seats, I gripped the lectern, secretly fighting waves of panic, while vertigo made my vision swirl and my stomach queasy. Somehow, words still came out of my mouth — words that were part of my lecture on vaccinations. As a college health and science writing instructor, I discuss vaccines every semester in an attempt to debunk the fallacy that they cause autism. But despite my regular speeches on the topic, they inevitably trigger a panic attack like the one I was currently battling in the classroom. See, vaccines involve needles. And since childhood, I’ve had needle phobia. Even thinking about them sends me spiraling into a private hell inside my mind, while my body gives way to symptoms like heart palpitations and even…

Expect rain. Those two simple words can ruin picnic plans or herald rescue for drought stricken crops. Few things in our lives are as universal as the weather. “It’s what’s going on in the atmosphere all around us all the time,” says Russ Schumacher, Colorado State climatologist and director of the Colorado Climate Center. “Storms and all the other interesting things that Earth’s atmosphere brings us have this big effect on our daily lives in a lot of ways.” But even though we tune in to local news stations or check apps to find out what the weather will bring, we don’t always trust the forecasts. You’ve probably heard the joke: Meteorology is the only occupation where you can be wrong all the time and still get paid for it.…

In many countries, a single public weather service is typically the only source available for forecasts, warnings and alerts. These meteorologists work for public (government) organizations or universities. By contrast, the United States has strong public, private (commercial) and university-based weather observation and forecasting programs. “We also are a large country and a populous country, and one with a great deal of weather variation. I think all those things have strengthened our interest in weather and our support for weather research and forecasting,” says Weather Underground’s Bob Henson. In other words, the U.S. is a bit of a weather powerhouse. Here, most forecasts originate at the National Centers for Environmental Prediction (NCEP). These centers are part of the National Weather Service (NWS), which itself is a part of the National…

Some researchers have hypothesized that, like lion manes protecting vulnerable parts of the animal’s face and neck while fighting with a competitor, beards have survival value. During hand-to-hand combat, “the theory was that beards might stop you from getting knocked out” by cushioning the blow, says Barnaby Dixson, an anthropologist at the University of Queensland, Australia. The idea itself took a hit when a 2018 Evolution and Human Behavior paper looked at results from the Ultimate Fighting Championship’s cage matches, which blend wrestling, kickboxing and other martial arts. “It’s pretty much a slugfest,” says Dixson, the study’s lead author. In the 600 fights analyzed, beards had no effect on knockouts or wins. Says Dixson: “Beards are fairly useless in terms of fighting.”…