内容：Edith Shao 编辑：Thomas Dai
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Fido's Human Age Gets New Estimates Eliene Augenbraun | December 27, 2019
[Dog barking.]
How old is your four-legged best friend? Common wisdom says that a dog ages seven years for every human year. But Tina Wang, a graduate student at the University of California San Diego, wanted a more accurate assessment. Her quest started five years ago when she rescued a dog from a shelter.
“I kind of just wanted to ask how old she was because I felt like they were giving me an age that was very sensible but I wasn't sure she was actually that old. So that kind of started this whole project.”
Wang worked in Trey Ideker’s lab, where they study changing patterns of DNA methylation in humans. Small chemical entities called methyl groups attach to stretches of DNA, which affects what sequences are active. As we age, some stretches of DNA get more methylated and others less. The pattern is so consistent over the course of most people’s lives that it can be used as an aging “clock.” The same process happens in dogs—and published reports existed from other labs about methylation patterns in dogs changing over time.
So Wang compared the age-related patterns in 320 humans and 104 Labrador retrievers.
“We knew that DNA methylation can predict age in many mammals but we didn't know exactly how much of this was shared throughout the progression of life and it wasn't clear if there was anything that was shared. And because of these similarities we were able to identify a conserved aging signature that allows you to estimate dog years from human years based on this molecular profile.”
The researchers say that dog years per human year change over the lifetime of a dog. For example, their method has a one-year-old dog being the equivalent of a 30-year-old human. A four-year-old dog is about 52. And dog aging per year slows considerably after that. To see a chart of the aging estimates, check out the paper at the BioRxiv website. [Tina Wang et al, Quantitative translation of dog-to-human aging by conserved remodeling of epigenetic networks]
Source: Scientific American https://www.scientificamerican.com/podcast/episode/fidos-human-age-gets-new-estimates/
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How 2019’s space missions explored distant worlds Maria Temming | December 23, 2019
[Time 2] From asteroids to exoplanets, spacecraft are leaving no space rock unturned. While agencies in China, India and Israel made headlines with missions to the moon, here are some other places that space probes scouted in 2019.
Zoom and enhance Touring Pluto in 2015 may have been New Horizons’ main event, but flying by what used to be called Ultima Thule was an awesome encore. The space probe zipped by this Kuiper Belt object, now called Arrokoth, on New Year’s Day. Scientists were on the edge of their seats as the probe snapped pictures and sent higher- and higher-resolution images over several weeks, revealing the visage of Arrokoth to look like an elongated blob, then a snowman and finally a pair of lumpy pancakes. Uncovering the origins of Arrokoth’s awkward shape may lend insight into the early stages of planet formation.
I spy exoplanets NASA’s Transiting Exoplanet Survey Satellite, or TESS, racked up eight exoplanet finds in its first few months of observation. That initial cache included some weirdos, such as a planet that is about as dense as pure water and a “lava world” known as LHS 3844b that sizzles at about 540° Celsius. TESS has since discovered a new type of exoplanet called an ultrahot Neptune, which appears to be a fluffy gas giant in the process of stripping down to its rocky core. [225 words]
[Time 3] Asteroids to go The Japan Aerospace Exploration Agency’s Hayabusa2 is expected to become the second spacecraft ever to bring a bit of asteroid back to Earth, after the original Hayabusa probe returned with a souvenir from the asteroid Itokawa in 2010. Hayabusa2 touched down on the asteroid Ryugu in February to fetch a sample from the asteroid’s surface. Then, to get a deeper sample, Hayabusa2 fired a copper projectile at Ryugu to punch a crater into the asteroid. The probe then ducked down to snag some rubble excavated from the interior. Scientists won’t know exactly how much of Ryugu was collected until Hayabusa2, which started its journey home on November 13, arrives at Earth in late 2020.
Another sample-return mission, NASA’s OSIRIS-REx, is still orbiting its asteroid. When the spacecraft first arrived at Bennu in December 2018, observations unveiled a rugged surface littered with boulders — bad news for a probe designed to navigate more beachlike terrain. Using OSIRIS-REx’s detailed mapping of Bennu from orbit, NASA selected a site for sample collection in the asteroid’s northern hemisphere. Bits of Bennu, to be returned in 2023, may reveal whether a similar asteroid could have delivered to early Earth a molecular starter pack for life.
Meanwhile, on Mars InSight arrived on the Red Planet in November 2018, and the rookie lander may have already captured the first recording of a Marsquake. Unlike tremors on Earth, underground rumblings on Mars are thought to result from the planet contracting as it cools. Studying such seismic signals could help scientists better understand the structure of Mars’ deep interior.
While InSight had its ear to the ground, the veteran Curiosity rover was measuring the consistency of a Martian mountain. As Curiosity scaled Mount Sharp, accelerometer readings indicated surprisingly loose rock beneath the rover’s wheels — suggesting that winds formed the mountain by sweeping sediment into a giant pile. [310 words]
Source: Science News https://www.sciencenews.org/article/how-2019-space-missions-explored-distant-worlds
Rotting-fruit art points up plants in peril Myles Karp | December 27, 2019
[Time 4] A number of the world’s most nutritionally and economically important crops are currently under siege by fungi, bacteria, and pests. Various species of Puccinia are attacking wheat; Fusarium oxysporum has it out for bananas; coffee is succumbing to Hemileia vastatrix and potatoes to Phytophthora infestans, and there are many others. Plant diseases limit food supplies, and they also cause economic distress by depressing export production and eliminating agricultural jobs.
An exhibit at the Harvard Museum of Natural History revolves around the theme of our food supply’s vulnerability to plant disease, using an unconventional conduit: early 20th-century glass models of rotting fruit.
Known as Harvard’s “Glass Flowers,” the Ware Collection of Blaschka Glass Models of Plants comprises over 4,300 sculptures of plants and plant parts fashioned entirely in glass by the Dresden, Germany-based father-and-son artisans Leopold and Rudolf Blaschka between 1887 and 1936.
In addition to the selection of works on permanent display, the “Fruits in Decay” exhibit features the collection’s exemplary models of diseased, rotting, and blighted fruiting plants. Strawberries covered in snowy Botrytis fuzz, exquisitely detailed leaves shriveled by Taphrina fungus, and mummified pears all glow under dim amber light—as much art as science.
Harbingers of affliction As fanciful as a glass sculpture of a withering peach may seem, the value of the plants has never been principally aesthetic or sentimental. Harvard originally commissioned the models as teaching tools, better than botanical illustrations or pressed specimens at demonstrating plants’ three-dimensional structure and color. The rotting fruit series was intended specifically to educate the public about the menace of plant disease. [262 words]
[Time 5] “Ames was highly concerned about this economic botany aspect of how people and plants are interacting,” explains Donald Pfister, Harvard’s Asa Grey professor of systematic botany, referencing early 20th-century Harvard botanist Oakes Ames. He commissioned the diseased fruit models created by Rudolf, the younger Blaschka, toward the end of his life, from 1924 to 1932. “And so he thought about these as a way to look at what we now call food security—or insecurity.”
Though the models were made nearly a hundred years ago, the theme is as salient as ever. Most of the illnesses depicted on Rudolf Blaschka’s plant models still afflict those crops. The New York Times reported earlier this month on the fast-expanding incidence of fire blight—now often resistant to antibiotics—on American apple orchards, including the razing of the entire heirloom collection at a botanical garden in Massachusetts.
In certain ways, global agriculture is more vulnerable than it has ever been to pathogenic threats, largely due to the widespread practice of monoculture, the cultivation of one crop over large production areas, limiting diversity for the sake of efficiency. Less genetic diversity means that crops have less resistance to disease.
According to a recent UN report, the practice is becoming more common, and is accompanied by other unsustainable aspects of food production. “In many parts of the world, biodiverse agricultural landscapes… are being replaced by large areas of monoculture, farmed using large quantities of pesticides, mineral fertilizers and fossil fuels,” the report says.
In a particularly egregious example of monoculture, nearly all bananas grown for export are genetically identical clones, and now the fungal malady called Panama disease Tropical Race 4 is wreaking havoc on banana farms around the world, disrupting a vital source of both food and employment. Harvard’s collection features glass models of banana plant parts, likely of a banana variety called Gros Michel. Since the models’ creation, that variety became commercially extinct, wiped out by an earlier strain of Panama disease. [329 words]
[Time 6] Investment and intervention Without significant investment and intervention, food security threats from pathogens will almost certainly become more common. Besides the need to feed an expanding population, climate change promises to complicate matters.
“Climate change will make many plant diseases more rampant because warming temperatures disable a crucial plant defense system against plant diseases,” says Sheng Yang He, a professor at Michigan State University and researcher at the MSU-Department of Energy Plant Research Laboratory.
Fungi, for example, often thrive in warmer environments, and as the world warms, the host ranges of damaging fungi will inevitably expand. That’s not to mention the agricultural repercussions of droughts, extreme weather conditions, and other predicted consequences of climate change.
“All crops, and therefore the human population, are at risk if we do not drastically increase efforts to figure out how to make crop plants more resilient to climate change,” said He.
In a paper he co-authored on the topic, He estimated that major crop loss from plant disease is already at a staggering 20 to 40 percent.
Indeed, Rudolf Blaschka’s glass models of decaying fruits are beautiful harbingers of affliction. But despite its gravity, the threat of plant disease is seriously underrecognized. “I think there’s a lot to be done about convincing people,” Pfister says.
During the Blaschkas’ time, the public may have made the connection between the beautiful multichromatic rings on a glass pear and the threat of famine more readily.
“When these were made, botanical literacy was quite high,” Pfister says. “People could come in and look at and understand families and so forth of the plants. That’s not the case these days.”
What changed? “It’s not sexy,” he says. [278 words]
Source: National Geographic https://www.nationalgeographic.com/science/2019/12/rotting-fruit-art-points-up-plants-in-peril/
In 2019 it became cool to be “real” online Tanya Basu | December 28, 2019
[Paraphrase 7] In May, Krystal Aranyani shared a video on YouTube that was unlike her usual fare. The yoga teacher wore no makeup, was poorly lit, and slouched in front of tapestries and pillows, her hand propped on her face in a thoughtful gesture.
“Hello, beloveds—welcome back to my channel,” she began, her usual salutation. “You may notice I look a bit different today. The other day I was thinking how I’ve never made a video without any makeup on, which is fine because people on social media, especially ones like myself that want to help others and make a career out of it, like to present ourselves in a certain way. But I’ve been meaning to make a little bit more of a real video for you guys to remind you that it’s not always like that 24/7 and we’re really just playing out roles in our lives.”
At one time, Aranyani’s approach might have seemed bold, perhaps even risky, for tampering with the image her viewers were accustomed to. Brave as she may have been, though, Aranyani’s video was one of many, many posts across social media in 2019 that rejected what had become the accepted aesthetic of online self-presentation: airbrushed, perfectly posed, like a fairy tale come to life.
When Instagram first launched in 2010, it was akin to a digital photo album. A normal person could shoot a normal photo with a normal smartphone and—with the help of a few filters and easy-to-use editing tools—create a stunning, professional-looking image.
For eight years, social media was all about the augmented look: Facebook birth announcements, Twitter ~personal news~ posts, YouTube makeup tutorials, carefully crafted lifestyle blogs, and more.
But in 2019, something changed. It became cool to be real. Like, really real.
Celebrities, of course, helped. The YouTube personality Emma Chamberlain has over 8 million followers, and her introductory reel on her YouTube page begins with her saying, “D’you know what? I’m going to be totally real with you guys!” She described in a recent profile why she often posts videos of herself crying: “Whenever I’m crying I like, weirdly, to document it. Every time I cry I always take one photo of myself afterwards because I like to look back and think ‘Remember when I was so upset about X, Y, and Z? Look at me now—I don’t care about that anymore!’”
Chamberlain is of the generation that has challenged what it means to be on social media. Millennials may have invented and adopted Facebook, and stuffed Twitter and Instagram with memes and snark and (sometimes fake) news. But Gen Zers now seem to be on a quest to post the most authentic, unretouched photos possible—ones that show them emoting, and in unflattering light, angles, and situations. Being real for this generation means recording a TikTok that documents one’s own struggle with mental illness. It means posting an image that shows a lopsided smile and eyes shut right when the camera goes off.
On the one hand, such content feels like the starting point for refreshingly candid conversations online. TikTok has become the platform of choice for teens for this very reason: in 30-second loops, they can be concise and punchy, tearing apart everything from Pete Buttigieg’s campaign dance routine to the Uighur crisis in China.
Rebecca Jennings at Vox described how TikTok’s appeal for teens can be mapped out by the “I’m ugly” trend. Depressing as it might seem on the surface, it’s empowering for teens to create content that attacks classic Instagram tropes like the before/after split screen. “Relatable videos are why people like TikTok in the first place,” Jennings notes. “And feeling unattractive on TikTok is one of the most relatable experiences of all.”
However, being authentic—being real—is often a performance in and of itself. Posts about taking the mask off, so to speak, are in fact very carefully worded and often paired with somber photos meant to communicate thoughtfulness and depth.
When Kim Kardashian, the archetypal influencer, gets “real,” she never truly breaks character.
In a video released this month, she talked about dealing with preeclampsia while pregnant and the five surgeries that followed. As painful and genuine as Kardashian’s experience was, it’s nearly impossible to ignore how practiced and staged everything in the video is. Perfectly lit, her symmetrical, made-up face offset by a brown teddy sweater and mauve wall, Kardashian’s moment of vulnerability is also a commercial for her shapewear brand, Skims.
This phenomenon has been called “aspirational realness,” the idea that a curated life that’s ever so messy in just the right photogenic ways is somehow authentic. But anyone who’s ever attempted to take a snapshot of brunch or use a toy to distract a baby into staying still for a photo knows that capturing the “real” is inherently not. It’s posed, takes many tries, and requires planning.
That extends to 2019’s trend of supposed soul-baring. It isn’t a coincidence that Aranyani’s heart-to-heart video dovetails nicely with her business as a yogi and empowerment coach. We get to witness Chamberlain’s tears because she has an odd penchant for self-documentation, sure, but underneath that is a keen understanding that emotions generate clicks. Same for Kardashian, the consummate professional. She is well aware that her brand relies on a seesaw of aspiration and relatability: she’s a billionaire businesswoman, but a mom of four, too.
So while it has become more acceptable to acknowledge that real life happens, in a way it’s just a new manifestation of the same urge for online notoriety. This year might have given us a tsunami of heartwarming TikTok videos of dancing with your mom or lip-synching a country song in your pajamas. But it’s the same endless loop: calculating the dynamics of a perfect digital extension of yourself to garner the dopamine rush of likes. Being “real” is just one way to do that. [982 words]
Source: MIT Technology Review https://www.technologyreview.com/s/614975/in-2019-it-became-cool-to-be-real-online-instagram-tiktok/
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发表于 2020-1-4 19:48:51
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