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7 Things You Didn't Know About Paragliding

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The first thing you need to know is, it's awesome. I tried it while in New Zealand last month, and speaking as someone who's got issues with heights, I can assure you that once you've hurled yourself off the cliff/mountain/ledge and are airborne, it's just about the most fun you're likely to have. (As proof, check out this video of my flight and my wife's landing; we're practically giddy.)

1. It's not to be confused with hang-gliding

I found this out literally as I was being driven up a hair-raising mountain switchback to the launch point. (I recommend finding out a little earlier.) The major difference lies in the wing shape and design. Hang gliders are solid wing structures, utilizing an aluminum frame to create a V-shaped wing that resembles the stealth bomber. Paragliders are soft wing structures, with no internal frame, which once inflated have an elliptical shape. Because they have a slower flying speed, they're much more forgiving than hang gliders, and as a result the learning curve is usually less steep for paragliding. Also, paragliders fold conveniently into a small bag, so you can take them mountain trekking then paraglide down when you're tired of being on a mountain. (Link.)

2. It's also not to be confused with parasailing

Parasails are essentially just parachutes, and are used by people being towed by boats at the beach or on lakes. They never get more than a few hundred feet high at most. The design of a paraglider wing is more like that of a 747 than a parachute -- it's designed to catch thermal updrafts and rise through the air, not just fall slowly to the ground. It's a much more dynamic experience, which is why glider pilots are called pilots, and people who use parachutes aren't really called anything.

3. It's not as dangerous as it sounds

Before I tried it, I thought paragliding was one of those things that only suicidal maniacs and adrenaline junkies attempted. I am neither. It's actually one of the safest airborne sports. Firstly, you're connected to the wing by at least 30 lines, any one of which is strong enough to support your weight. There is a risk of the wing deforming and/or collapsing while in flight, but this is rare and usually due to pilots unwisely deciding to fly in bad weather. If you're at a sufficient altitude (more than 700 feet or so), the reserve parachute most glider pilots wear will guide them safely to the ground; the danger is to be too close to the ground when performing some dangerous maneuver, in which case your parachute won't have time to inflate properly before you splat back to earth.

4. It was named by NASA

Leonardo Da Vinci may have designed the first parachute, but NASA helped design, and name, the paraglider. In 1961, a French engineer named Pierre Lemoigne took the first steps by cutting strategically placed vents in a parachute which allowed it to ascend into the air and be steered, but it was NASA who developed what was known as a "sail wing," for use in recovery of lunar capsules, into the paraglider.

5. It's more comfy than the chair you're sitting in right now

chair.jpgWell, probably. Unlike most harness-based activities, like rappelling and parachuting, the focus isn't on a series of pinchy straps and clips around your legs and midsection. Modern paragliding harnesses connect you to something akin to a lounge chair, in which your reserve parachute and other goodies are stored, and some of them even feature lumbar support. After you leap from the precipice of choice and the glider inflates, you simply slide the "chair" under your bum, and ride your flying barcalounger wherever the wind takes you.

6. You've got brakes and gas

Well, sort of -- there's certainly no combustion engine on board, but pilots do have a great deal of control over their gliders. Controls held in each of the pilot's hands connect to the trailing edge of the left and right sides of the wing, and these can be used to steer and to adjust speed. The only thing directly under their control is ascent -- that depends on their skill (and luck) at finding rising columns of thermal air, which can loft the glider great distances.

7. You can travel across the country this way

If you're really, really good, that is. Most paraglider flights last between 15-25 minutes, depending on weather conditions. But pilots who are especially skilled at finding and exploiting thermal columns of rising air can use them to hop and skip their way across long distances, like paragliding champ Will Gadd, who holds the world record for longest paraglider flight, at 263 miles.

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iStock // Ekaterina Minaeva
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technology
Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
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iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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Cs California, Wikimedia Commons // CC BY-SA 3.0
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science
How Experts Say We Should Stop a 'Zombie' Infection: Kill It With Fire
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Cs California, Wikimedia Commons // CC BY-SA 3.0

Scientists are known for being pretty cautious people. But sometimes, even the most careful of us need to burn some things to the ground. Immunologists have proposed a plan to burn large swaths of parkland in an attempt to wipe out disease, as The New York Times reports. They described the problem in the journal Microbiology and Molecular Biology Reviews.

Chronic wasting disease (CWD) is a gruesome infection that’s been destroying deer and elk herds across North America. Like bovine spongiform encephalopathy (BSE, better known as mad cow disease) and Creutzfeldt-Jakob disease, CWD is caused by damaged, contagious little proteins called prions. Although it's been half a century since CWD was first discovered, scientists are still scratching their heads about how it works, how it spreads, and if, like BSE, it could someday infect humans.

Paper co-author Mark Zabel, of the Prion Research Center at Colorado State University, says animals with CWD fade away slowly at first, losing weight and starting to act kind of spacey. But "they’re not hard to pick out at the end stage," he told The New York Times. "They have a vacant stare, they have a stumbling gait, their heads are drooping, their ears are down, you can see thick saliva dripping from their mouths. It’s like a true zombie disease."

CWD has already been spotted in 24 U.S. states. Some herds are already 50 percent infected, and that number is only growing.

Prion illnesses often travel from one infected individual to another, but CWD’s expansion was so rapid that scientists began to suspect it had more than one way of finding new animals to attack.

Sure enough, it did. As it turns out, the CWD prion doesn’t go down with its host-animal ship. Infected animals shed the prion in their urine, feces, and drool. Long after the sick deer has died, others can still contract CWD from the leaves they eat and the grass in which they stand.

As if that’s not bad enough, CWD has another trick up its sleeve: spontaneous generation. That is, it doesn’t take much damage to twist a healthy prion into a zombifying pathogen. The illness just pops up.

There are some treatments, including immersing infected tissue in an ozone bath. But that won't help when the problem is literally smeared across the landscape. "You cannot treat half of the continental United States with ozone," Zabel said.

And so, to combat this many-pronged assault on our wildlife, Zabel and his colleagues are getting aggressive. They recommend a controlled burn of infected areas of national parks in Colorado and Arkansas—a pilot study to determine if fire will be enough.

"If you eliminate the plants that have prions on the surface, that would be a huge step forward," he said. "I really don’t think it’s that crazy."

[h/t The New York Times]

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