CLOSE
Original image

Rosalind Franklin and the Search for DNA

Original image

In 1962, the Nobel Prize in Physiology or Medicine was a awarded jointly to Francis Harry Compton Crick, James Dewey Watson, and Maurice Hugh Frederick Wilkins for their discovery of the structure of DNA. Many are aware of Watson and Crick's work in "discovering" DNA in 1953. But the world had known about DNA since 1944, when Oswald Avery declared it to be the molecule that carried genetic information. For years, scientists had raced to learn more about DNA. Watson and Crick worked on DNA in the Cavendish Laboratory at the University of Cambridge. Physicist Maurice Wilkins was one of several scientists working on DNA at Kings College in London. And so was Rosalind Franklin

1962 Nobel laureates Maurice Wilkins, Max Perutz, Francis Crick, John Steinbeck, James Watson, and John C Kendrew. Photo from Keystone/Getty Images.

Sir John Randall assembled a team of scientists to work on the problem of DNA at his Kings College laboratory that included both Wilkins, who had just left work on the Manhattan Project, and Franklin, who had become renowned for her work in X-ray crystallography in Paris. Wilkins had been working on X-ray diffraction, but when his work lagged, Randall assigned Rosalind Franklin and graduate student Raymond Gosling to study the structure of DNA by X-ray diffraction. Franklin was delayed in getting to Kings College in 1950 due to her work in France. When she arrived in 1951, Maurice Wilkins missed the meeting in which she was introduced as a colleague. That led to an important misunderstanding.

Franklin was under the impression that the X-ray diffraction was her project. Wilkins assumed, depending on the source, that either Franklin was working as his partner or as his assistant. Because of this difference of views, the two did not get along well. Franklin had long been patronized for being a woman scientist, and she preferred to work alone or with her assistant Gosling.

Watson and Crick began to suspect that DNA took a helical pattern, but were looking into the possibility of a triple-twist helix. Franklin had her doubts about a helix pattern at all, because her mathematical models did not support the theory, but she did not dismiss the possibility.

In May of 1952, Franklin and Gosling took a X-ray diffraction image that became known as "Photo 51." Gosling presented the photo to Wilkins as part of his graduate work. In January of 1953, Wilkins shared the picture, and some of Franklin's unpublished notes, with Watson and Crick, without Franklin's knowledge. Watson and Crick saw that Photo 51 held the secret that confirmed the double-helix model, and ran with it.

Franklin studied Photo 51 and independently saw the double-helix model in February of 1953. She and Gosling prepared a paper in March, and it appeared in the journal Nature along with Watson and Crick's announcement of the double-helix discovery in April of 1953. Wilkins also had an article on DNA structure in the same issue. Franklin was unaware of Watson and Crick's breakthrough before publication, but she accepted it, not knowing how her work contributed to it. She went on to Birkbeck College to work on viruses. While Franklin poured herself into new research, Watson and Crick were celebrated for the discovery of DNA.

Rosalind Franklin, born in 1920, received her bachelor's degree in chemistry from Cambridge University in 1941 and her Ph.D. in 1945. She worked constantly in the laboratory until she was diagnosed with ovarian cancer in 1956. Franklin died in 1958 at age 37. There is speculation that her years of work with X-rays, during which she took little if any precaution against radiation, contributed to her death.

Comic by Kate Beaton of Hark! A Vagrant.

Franklin was not eligible for a Nobel in 1962 because they are never awarded posthumously. But when Crick, Watson, and Wilkins won the Nobel, none of them gave Franklin any credit for her contribution to the research. Interest in her work was ignited when James Watson published a memoir in 1968 called The Double Helix, in which he criticized Franklin's appearance and minimized her role in DNA research. During her life, Franklin had been a world-renowned chemist, virologist, and expert in crystallography within the scientific community. Then the backlash generated by Watson's book made Franklin a symbol of sexism in science, as the unsung hero of DNA research. Dr. Franklin would probably find that strange, but might possibly find it satisfying.

Original image
iStock // Ekaterina Minaeva
technology
arrow
Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
May 21, 2017
Original image
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!

Original image
iStock
Sponsor Content: BarkBox
arrow
8 Common Dog Behaviors, Decoded
May 25, 2017
Original image
iStock

Dogs are a lot more complicated than we give them credit for. As a result, sometimes things get lost in translation. We’ve yet to invent a dog-to-English translator, but there are certain behaviors you can learn to read in order to better understand what your dog is trying to tell you. The more tuned-in you are to your dog’s emotions, the better you’ll be able to respond—whether that means giving her some space or welcoming a wet, slobbery kiss. 

1. What you’ll see: Your dog is standing with his legs and body relaxed and tail low. His ears are up, but not pointed forward. His mouth is slightly open, he’s panting lightly, and his tongue is loose. His eyes? Soft or maybe slightly squinty from getting his smile on.

What it means: “Hey there, friend!” Your pup is in a calm, relaxed state. He’s open to mingling, which means you can feel comfortable letting friends say hi.

2. What you’ll see: Your dog is standing with her body leaning forward. Her ears are erect and angled forward—or have at least perked up if they’re floppy—and her mouth is closed. Her tail might be sticking out horizontally or sticking straight up and wagging slightly.

What it means: “Hark! Who goes there?!” Something caught your pup’s attention and now she’s on high alert, trying to discern whether or not the person, animal, or situation is a threat. She’ll likely stay on guard until she feels safe or becomes distracted.

3. What you’ll see: Your dog is standing, leaning slightly forward. His body and legs are tense, and his hackles—those hairs along his back and neck—are raised. His tail is stiff and twitching, not swooping playfully. His mouth is open, teeth are exposed, and he may be snarling, snapping, or barking excessively.

What it means: “Don’t mess with me!” This dog is asserting his social dominance and letting others know that he might attack if they don’t defer accordingly. A dog in this stance could be either offensively aggressive or defensively aggressive. If you encounter a dog in this state, play it safe and back away slowly without making eye contact.

4. What you’ll see: As another dog approaches, your dog lies down on his back with his tail tucked in between his legs. His paws are tucked in too, his ears are flat, and he isn’t making direct eye contact with the other dog standing over him.

What it means: “I come in peace!” Your pooch is displaying signs of submission to a more dominant dog, conveying total surrender to avoid physical confrontation. Other, less obvious, signs of submission include ears that are flattened back against the head, an avoidance of eye contact, a tongue flick, and bared teeth. Yup—a dog might bare his teeth while still being submissive, but they’ll likely be clenched together, the lips opened horizontally rather than curled up to show the front canines. A submissive dog will also slink backward or inward rather than forward, which would indicate more aggressive behavior.

5. What you’ll see: Your dog is crouching with her back hunched, tail tucked, and the corner of her mouth pulled back with lips slightly curled. Her shoulders, or hackles, are raised and her ears are flattened. She’s avoiding eye contact.

What it means: “I’m scared, but will fight you if I have to.” This dog’s fight or flight instincts have been activated. It’s best to keep your distance from a dog in this emotional state because she could attack if she feels cornered.

6. What you’ll see: You’re staring at your dog, holding eye contact. Your dog looks away from you, tentatively looks back, then looks away again. After some time, he licks his chops and yawns.

What it means: “I don’t know what’s going on and it’s weirding me out.” Your dog doesn’t know what to make of the situation, but rather than nipping or barking, he’ll stick to behaviors he knows are OK, like yawning, licking his chops, or shaking as if he’s wet. You’ll want to intervene by removing whatever it is causing him discomfort—such as an overly grabby child—and giving him some space to relax.

7. What you’ll see: Your dog has her front paws bent and lowered onto the ground with her rear in the air. Her body is relaxed, loose, and wiggly, and her tail is up and wagging from side to side. She might also let out a high-pitched or impatient bark.

What it means: “What’s the hold up? Let’s play!” This classic stance, known to dog trainers and behaviorists as “the play bow,” is a sign she’s ready to let the good times roll. Get ready for a round of fetch or tug of war, or for a good long outing at the dog park.

8. What you’ll see: You’ve just gotten home from work and your dog rushes over. He can’t stop wiggling his backside, and he may even lower himself into a giant stretch, like he’s doing yoga.

What it means: “OhmygoshImsohappytoseeyou I love you so much you’re my best friend foreverandeverandever!!!!” This one’s easy: Your pup is overjoyed his BFF is back. That big stretch is something dogs don’t pull out for just anyone; they save that for the people they truly love. Show him you feel the same way with a good belly rub and a handful of his favorite treats.

The best way to say “I love you” in dog? A monthly subscription to BarkBox. Your favorite pup will get a package filled with treats, toys, and other good stuff (and in return, you’ll probably get lots of sloppy kisses). Visit BarkBox to learn more.

SECTIONS
BIG QUESTIONS
BIG QUESTIONS
WEATHER WATCH
BE THE CHANGE
JOB SECRETS
QUIZZES
WORLD WAR 1
SMART SHOPPING
STONES, BONES, & WRECKS
#TBT
THE PRESIDENTS
WORDS
RETROBITUARIES