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Armchair Field Trip: The Grassy Knoll

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Whether you believe that Lee Harvey Oswald acted alone or think that John F. Kennedy's assassination in 1963 was the result of a huge government conspiracy, there's no question that Dallas is the place where it all went down. Since that's where I was last week, of course I had to check out the Grassy Knoll.

As a side note, when we were consulting the GPS system in our rental car, we weren't totally sure how to look up the site of JFK's assassination. We didn't know it had taken place at Dealey Plaza and didn't know what the name of the museum was (or, in fact, that there even was a museum). We jokingly wondered if it would be listed under "Grassy Knoll" in the GPS Yellow Pages. Guess what? It was.


Anyway, when we got to Dealey Plaza, we discovered the Sixth Floor Museum, a museum dedicated to JFK's life, death and legacy. The museum is, as its name implies, on the sixth floor of what used to be known at the Texas School Book Depository where Lee Harvey Oswald fired the shots that killed Kennedy (or didn't fire the shots, depending on your theory). Maybe it's just me, but I found it rather morbid that the museum was housed in the very place JFK's (possible) killer holed up to shoot him.

At the museum, I learned some interesting facts about the events surrounding that fateful day.

BookDepository2.jpg"¢ Lee Harvey Oswald was an employee at the Book Depository at the time.

"¢ There were concerns about the President's safety in Dallas because United Nations Ambassador Adlai Stevenson has been hit with a protest sign and spat on in the city less than a month earlier.

"¢ Minutes before JFK was shot, a local T.V. station announced that it was clear that any worries about anti-Kennedy activists in Dallas were completely unfounded.

"¢ A Presidential car with a bulletproof top didn't exist then, although plans for one were in the works.

Zapruder.jpg"¢ The only video known to exist of the entire event is the Abraham Zapruder video, which he sold to Life magazine for $150,000. He also turned a copy of the film over to the Secret Service.

"¢ Vice President Lyndon B. Johnson was sworn in as President an hour and 38 minutes after President Kennedy was pronounced dead. First Lady Jacqueline Kennedy stood next to him wearing the same clothes she was wearing when her husband was shot approximately two hours earlier.

"¢ JFK's funeral took place on November 25th, 1963 "“ his son's third birthday.

"¢ Lee Harvey Oswald was pronounced dead two days and seven minutes after President Kennedy was pronounced dead.

"¢ The plaza is named for George Bannerman Dealey who published the Dallas Morning News for a number of years. He also was a key player in helping to revitalize the Dealey Plaza area.

"¢ Buildings in Dealey Plaza have not been changed since 1963, which is really noticeable when looking at the extremely modern Dallas skyline behind it.

And, oddly, available in the gift shop were action figures of not just of JFK, but also Abraham Lincoln, Uncle Sam, and"¦. Laura Bush?? (Is it just me, or is that a strange combo?)

Well, I'm hesitant to ask, but what do you think? Single shooter? Government conspiracy? JFK is actually still alive and hanging out in a bar somewhere with Elvis and Tupac??

Previous Armchair Field Trips:

The Corn Palace
The International Spy Museum
Intercourse, Pennsylvania
Ogunquit, Maine
Aquinnah, Massachusetts

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iStock // Ekaterina Minaeva
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
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]