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One More Odd Thing I Just Learned About Fish

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When I’m not blogging for mental_floss, I can usually be found wearing bright orange rubber pants and gutting, cutting and selling fish at my local Whole Foods (and winning awards for it). Sometimes, my two worlds collide and I find some scientific research involving my ocean-dwelling friends that begs for a blog post. This is one of those times.


Take the Last Train to Lobsterville, I’ll Meet you at the Station


Panulirus argus, the Caribbean spiny lobster, spends most of its time in shallow waters among coral reefs and mangrove swamps in the western Atlantic Ocean and Caribbean Sea (as far south as Brazil and as far north as North Carolina). Every year in mid-Fall, much of their range gets hit with increased storm activity and the usually pleasant water conditions get disrupted by high winds, water turbulence, colder temperatures, and turbidity from kicked-up sediment.

After the first storm, many of the lobsters (especially those in southeast Florida, the Florida Keys, Bimini and Grand Bahama and eastern Yucatan, Mexico), which are normally nocturnal and solitary, become active in the day and gather in groups to form queues of up to 65 individuals. Once a queue is sorted out, the lobsters begin marching – single-file, with each individual maintaining antennae-to-cephalothorax contact with the lobster in front of them – into deeper, calmer water.

Researchers hypothesize that these mass migrations are a response to the autumn storms, which can make the shallows too cold and turbulent for normal lobster activity and can even kill molting individuals. The cue to begin lining up appears to be the sharp drop in water temperature; captive spiny lobsters in laboratories have been observed to remain active during the day and queue up when the temperature of their tanks are dropped.

All the lobsters seem to have an innate sense of the migratory bearing, as followers occasionally break rank and form separate queues that maintain the normal pace and direction and quick removal of a queue leader by researchers has resulted in the next lobster in line continuing to lead the train on the migratory.

A mass exodus from an unfriendly environment makes sense, but why would creatures who normally prefer to go out at night by themselves join into groups and travel during the day?

The conga line formation seems to serve two purposes. One, it reduces drag on the lobsters that aren’t leading and lets them conserve energy. Lobsters in a queue of 20+ individuals sustain only about half the drag of solo travelers. Two, if a predator happens upon the caravan, the queue formation allows the lobsters to quickly “circle the wagons” and go into a defensive formation that protects their vulnerable legs and presents their sharp antennae to predators.

Want to see the lobsters in action? With an epic musical score and the dulcet tones of Sir David Attenborough? Then you’ve come to the right place.

Reference: Kanciruk, P., Herrnkind, W.. (1978). “Mass Migration of Spiny Lobster, Panulirus Argus (Crustacea: Palinuridae): Behavior and Environmental Correlates.” Bulletin of Marine Science, Volume 28, Number 4.

Herrnkind, W., Kanciruk, P., Halusky, J., McLean, R.. (1973). “Descriptive characterization of mass autumnal migrations of spiny lobster Panulirus argus.” Proceedings of the Gulf and Caribbean Fisheries Institute, 25, 79-98.

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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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iStock
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Health
One Bite From This Tick Can Make You Allergic to Meat
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iStock

We like to believe that there’s no such thing as a bad organism, that every creature must have its place in the world. But ticks are really making that difficult. As if Lyme disease wasn't bad enough, scientists say some ticks carry a pathogen that causes a sudden and dangerous allergy to meat. Yes, meat.

The Lone Star tick (Amblyomma americanum) mostly looks like your average tick, with a tiny head and a big fat behind, except the adult female has a Texas-shaped spot on its back—thus the name.

Unlike other American ticks, the Lone Star feeds on humans at every stage of its life cycle. Even the larvae want our blood. You can’t get Lyme disease from the Lone Star tick, but you can get something even more mysterious: the inability to safely consume a bacon cheeseburger.

"The weird thing about [this reaction] is it can occur within three to 10 or 12 hours, so patients have no idea what prompted their allergic reactions," allergist Ronald Saff, of the Florida State University College of Medicine, told Business Insider.

What prompted them was STARI, or southern tick-associated rash illness. People with STARI may develop a circular rash like the one commonly seen in Lyme disease. They may feel achy, fatigued, and fevered. And their next meal could make them very, very sick.

Saff now sees at least one patient per week with STARI and a sensitivity to galactose-alpha-1, 3-galactose—more commonly known as alpha-gal—a sugar molecule found in mammal tissue like pork, beef, and lamb. Several hours after eating, patients’ immune systems overreact to alpha-gal, with symptoms ranging from an itchy rash to throat swelling.

Even worse, the more times a person is bitten, the more likely it becomes that they will develop this dangerous allergy.

The tick’s range currently covers the southern, eastern, and south-central U.S., but even that is changing. "We expect with warming temperatures, the tick is going to slowly make its way northward and westward and cause more problems than they're already causing," Saff said. We've already seen that occur with the deer ticks that cause Lyme disease, and 2017 is projected to be an especially bad year.

There’s so much we don’t understand about alpha-gal sensitivity. Scientists don’t know why it happens, how to treat it, or if it's permanent. All they can do is advise us to be vigilant and follow basic tick-avoidance practices.

[h/t Business Insider]

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