DiscoverOctober 2018的目錄

It was an autumn day, and I was standing in the kitchen, hunched over the counter and trying to figure out how many calories were in a bowl of homemade yogurt and fruit. And I was frustrated. I was 16, and my best friend and I had gone to our first Weight Watchers meeting. It was the rage in the mid-1980s, and even though I was an athlete, like many teen girls I didn’t necessarily like what I saw in the mirror. But after a week or so of logging every meal and snack and calculating the calories, I had had enough. I went back to my routine of chowing what I wanted, running and skiing, and let that be that. And it’s still pretty much what I do; as…

MOTION DETECTOR For most patients, getting an MRI means holding still while a massive machine scans a body part, building an image one slice at a time. But researchers at the New York University School of Medicine have engineered a novel MRI design woven into a flexible glove that, for the first time, can capture detailed images of moving joints (inset). The device shows potential in diagnosing repetitive strain injuries and creating a more versatile hand anatomy atlas, the researchers say.…

UNDER THE SEA, all the way at the bottom, is what marine researchers refer to as the benthic zone. It’s the lowest layer of the ocean — of any body of water, really — including any sediment. It’s home to many bottom-dwelling critters, like sponges and sea worms, that experts call benthos. The region is not always as deep down as you’d think, either. In oceans, the benthic zone starts at the shoreline and follows the continental slope to the deepest depths.…

Keto Diets Ketosis occurs when the body, deprived of food for 12 hours or more, switches its energy source from carbs and glucose to fatty acids. The process generates ketone bodies that may have healthy effects. Keto diets, composed of low-carb, high-protein and high-fat foods, can also spark this metabolic switch. Since the 1920s, keto diets have been used in medicine to reduce epileptic seizures. More recently, the diets have supplemented standard treatments for Type 2 diabetes and cancer, with promising results. Over the last few years, keto diets have gained mainstream popularity. Some celebrities and sports stars embrace them, and people who fast use the regimen to further push their body into ketosis. But followers beware, says nutrition researcher Michelle Harvie. Dieters going keto tend to lose weight, but…

• The largest known Jupiter Trojan, 624 Hektor, is just 140 miles (225 km) wide, smaller than the 15 largest main belt asteroids. At least 24 moons are larger than Hektor. • The smallest known Trojan is 2002 CO208, discovered in February 2002 by the Lincoln Near-Earth Asteroid Research project (LINEAR) near Socorro, New Mexico. It’s an estimated 4 miles (6.6 km) in diameter. Smaller objects surely exist in both camps, but no one knows the actual numbers or sizes. The size distribution of the discovered Trojans suggests that the smaller bodies are the remains left by collisions of larger Trojans. • Hektor is the most elongated jovian Trojan at 125 by 230 miles (200 by 370 km). Observations made with the Keck II 10-meter telescope in 2006 showed that…

Alec Nielsen typed a few lines of code on his laptop, and a circuit schematic appeared in another window. Unlike most people who design circuits, however, he wasn’t making a computer chip. He was designing strands of DNA. Nielsen and a growing number of researchers want to hijack the biochemical processes of living cells to turn them into microscopic cyborgs — part living things, part programmable machines. These cellular cyborgs could one day step in when your body falls short in its attempts to hunt cancer cells, tamp down overactive immune responses or adjust the gut microbiome. Key to this vision is controlling how cells sense and respond to their environments, says Christopher Voigt, a bioengineer at MIT and co-founder of Asimov, a biotech startup that Nielsen leads. In nature,…

What’s Wrong With Octopi? (“Everything Worth Knowing: Octopuses,” July/August 2018) I’ve been reading Discover since the first promotional issue hit my mailbox eons ago, and I look forward to every issue. I loved the latest Everything Worth Knowing issue, especially the enlightening article on listeria. The main reason I am writing, though, is octopi! I have often wondered why it became octopuses, which I find terribly awkward. I will now go with octopodes and confuse everyone. Thank you so much for keeping the magazine as excellent as it’s always been. Roy Blazejowski Meriden, Conn. Trippy Treatment (“Into the Mystic,” April 2018) I was excited to see this article, and I hope to hear about more research on the therapeutic benefits of psilocybin. I’d like to see the Drug Enforcement Administration…

SHOTS RANG OUT ACROSS a Phoenix apartment complex one cool desert night last December. A patrolman arrived to investigate. Cleophus Cooksey Jr., 36, answered his knock at the door — covered in blood. His mom and stepdad were dead inside. Within just days (short work for crime-solving), detectives discovered that distinct markings on the bullets from the apartment matched others from violent crime scenes across the Phoenix area. Cooksey’s guns ultimately tied him to nine gruesome murders that had occurred over a three-week period. The quick analysis came thanks to a new digital technique for comparing the markings on bullets. It’s a long-awaited technological update that removes subjective human interpretation and — once widely adopted — could revolutionize solving violent crimes. Forensic scientists around the world currently rely on a…

Game Time From football hooligans to post-playoff riots, watching sports can seem like a violent activity. But the societal pastime of settling in for the big game might actually help curb crime. A study from the University of California, Davis, found that in Chicago — a city known for its sports franchises as well as its crime — reports of law-breaking dropped when games were on. DROP IN CRIME WHEN… CRIMES REPORTED… Degrees of Separation From screen time to ancient footprints. 1 HOUR After spending more than this much time on screened devices, teens reported being unhappier than if they ditched their devices before the 60-minute mark. And the longer they spent glued in front of a screen, the unhappier they reported feeling. 800 MILLION The number of U.K.- based…

TROJAN COURSE We know little about Jupiter’s Trojan asteroids, which orbit ahead of and behind the solar system’s largest planet. But a spacecraft named Lucy, slated for launch in 2021, will give astronomers a much closer look at these clusters of rocky bodies. Read about this unprecedented mission on page 58. And while the 60-year search for extraterrestrials hasn’t found any alien evidence, it has produced more than a few false alarms (page 64).…

Crickets Are the New Cows (“A New Animal Farm,” July/August 2018) Meat — it’s what’s for dinner. Though maybe not for much longer. Entrepreneurs are working to find a protein alternative to serve up to the public, and it looks like crickets could be the answer. Twitter users respond to the idea of mass cricket consumption: @PeterPumer (Butter Emails) If it’s a matter of forestalling climate change for a few more years, I’m taking one for the team. @praisehonk (Jimjamyaha) Nah, jog on. We know how this goes and why they want to be able to feed their lower classes insects. Eat it yourself. Feedback is edited for space and clarity.…

ONCE YOU BECOME AN ADULT, it’s all downhill for your neurons: You can lose them, but you can’t gain any more. That was the prevailing theory until research over the last two decades convinced scientists that older brains do create new neurons — a process called neurogenesis. Neurons are added to two regions of the brain, most notably the hippocampus, where they may contribute to the region’s role in learning and memory. Or maybe not: The neurogenesis debate was recently reignited. In Science Smackdown, we let experts argue the evidence. The Claim NOT A SINGLE NEW NEURON In a March paper in Nature, researchers at the University of California, San Francisco said they couldn’t find any evidence of adult neurogenesis. “If it happens, it is a very rare phenomenon,” says…

Popular Water-Only or Low-Calorie (500-600) Fasting Plans 1. Time-restricted feeding: Eating within a specific window of time in a 24-hour period. The most popular is 18:6, eating only during a six-hour period of a 24-hour day. Other variations are 20:4, 22:2 and 23:1. 2. Alternate-day fasting: Fasting every other day. 3. Intermittent fasting: Fasting one day or several days a week. Most popular is 5:2 — eating normally five days a week, fasting two days a week. How Low Can Calories Go? People can live days with no food and water, and weeks or several months consuming only water. In lab animals, when calorie intake is cut by more than 50 percent, they eventually die of complications from starvation. In the final stages of starvation, the body, depleted of glucose…

Imagine waking up in a Salvador Dalí painting. You reach over to hit the snooze button on your alarm clock, only to discover that it oozed into a puddle during the night. The sun rising outside your window illuminates an elephant tottering down the street, its legs impossibly skinny stilts a hundred feet tall. In this fantastic reality, everything is slowly but continuously distorting itself. Your coffee mug morphs into a doughnut, as if made of putty that’s been pinched and pulled. Breakfast is a confusing experience, as everyday items lose their identities. This may sound like a bad trip. We all know that things in the real world tend to have fixed shapes; the letter L is different from the letter M. But in the funhouse world of topology,…

Ninety-five days separated her from the gallows. It was 1923. Sabella Nitti was convicted of killing her husband, becoming the first woman in Chicago sentenced to die. The method would be hanging. A badly decomposed body found in a suburban sewer was Nitti’s missing husband, Francesco, prosecutors said. No evidence linked Nitti to the crime scene, and there appeared to be no motive. But Nitti’s oldest son had his own motives; after Francesco went missing, the son swooped in and claimed the meager estate for himself. Nitti pushed back in probate court, and the son was ordered to repay his mother $800. On the witness stand, the son defiantly identified the corpse as his father and named his mother as the killer. Edward Hatton, a forensic pathologist, testified at the…

1 It’s a common misconception, but poison, toxin and venom are not interchangeable terms. Think of them instead as potentially lethal nesting dolls. 2 Poisons are any substance that can cause harm, including death, to an organism. Poisons that are not toxins include, for example, radiation, lab-engineered pesticides and lead. 3 Toxins, however, are usually defined as poisons produced by living organisms, typically as a means of defense or to subdue prey. Some toxinologists (yes, that’s the word for people who study toxins) argue that toxins are any poison that requires only a tiny dose to be harmful, but theirs is a field-specific definition. 4 Complicating matters: Poisons in general, whether or not they’re toxins, can be categorized by the systems they target. Cardiotoxins cause heart damage, for example, while…