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Dietribes: Fun Facts about Sushi

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Sushi is a fairly new phenomenon in the United States. I have quite a few relatives who have never in their lives ventured to a sushi joint and enjoyed the wonderful experience of raw fish and rice. Though a big fan of it myself (as a person who even occasionally boils up seaweed for a snack), there's a lot I still don't know about the history and art of sushi. So let's dive in, shall we?

"¢ Edomae-sushi was first brought to the United States from Tokyo in the early 1960s. While looking for Japanese products to sell in the US, executives from Mutual Trading Company instead brought back an entire culinary experience, which they kicked off in Los Angeles. In the way America must make things its own, the California Roll was soon born. It was originally created to substitute for a maki roll made with toro (fatty tuna). Because the fish was seasonal, the thought was to create a roll that had the similar texture and flavor as toro when the fish was out of season.

zen-of-fish.jpg"¢ From Trevor Corson's book The Zen of Fish, "Sushi began as a way of preserving old fish. Rice farmers in Southeast Asia would pack fish in jars with cooked rice to preserve it. The fermented result tasted more like stinky cheese than like fresh hamachi; the Japanese, in adopting the strategy, gradually shortened the fermentation time, developing a fresher style of sushi that still relied on fermented rice for its distinctive sour taste."

"¢ Still, Some hungry soul got tired of waiting for his sushi to ferment. What we now think of as sushi — Edo-mae nigiri — was invented as fast food for laborers, served by outdoor vendors from small carts. Soy sauce was offered, probably to mimic the fermented fish taste of the earlier style. (For more, read this.)

"¢ Regarding that little bamboo leaf, "the bamboo leaf was a sign of freshness, conveying the message that sushi is perishable and should be eaten before the bamboo leaf dries out." I don't think that counts for the plastic ones included in the Publix containers, although, "the leaves prevented the flavors from contaminating each other and added a mild antibacterial function. The green pieces of decorative plastic that are still served with takeout sushi are a carryover from these early practices. Some brands of plastic are even coated with antibacterial chemicals." (From The Zen of Fish.)


"¢ Making sushi is no easy feat—traditional sushi chefs undergo years of training. However, there are other options with the California Sushi Academy, including an intensive 12-week sushi chef course, which consists of 250 in-class hours plus 100 internship hours.

"¢ Still, there is a great disparity among sushi chefs. According to this incredible podcast from NPR, "Most of Japan's more than 30,000 sushi restaurants still refuse to hire women, and many men refuse to eat sushi that a woman has prepared. Men often believe that women have a higher body temperature and other physiological differences that make them unsuitable to prepare something as delicate as sushi."

"¢ On a different note, for $300/hr you can hire a model to act as a human sushi plate. There's something vaguely cannibalistic about this, but I would have still considered it as a side job while I was in college.

"¢ If you're like me, this post has made you crave some serious sushi. Here are some great tips and etiquette regarding sushi, and how to brave that intimidating sushi bar (I admit I am one who often lacks courage and simply sits at a table.) Also, a look at the menus of 50 major sushi places around the U.S., and where they get their fish. Plus, hints on how to spot good sushi versus the bad.

OK fellow Flossers, I would love to know of any suggestions about making your own sushi, the best places to learn, or even any sushi stories you have to share (like the first time you tried wasabi ... for me, I thought my brain had exploded). Although I'm keeping mum on any tales regarding me, copious amounts of sushi, and several rounds of sake bombs.

Hungry for more? Venture into the Dietribes archive.

"˜Dietribes' appears every Wednesday. Food photos taken by Johanna Beyenbach. You might remember that name from our post about her colorful diet.

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iStock // Ekaterina Minaeva
Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
May 21, 2017
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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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Scientists Think They Know How Whales Got So Big
May 24, 2017
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It can be difficult to understand how enormous the blue whale—the largest animal to ever exist—really is. The mammal can measure up to 105 feet long, have a tongue that can weigh as much as an elephant, and have a massive, golf cart–sized heart powering a 200-ton frame. But while the blue whale might currently be the Andre the Giant of the sea, it wasn’t always so imposing.

For the majority of the 30 million years that baleen whales (the blue whale is one) have occupied the Earth, the mammals usually topped off at roughly 30 feet in length. It wasn’t until about 3 million years ago that the clade of whales experienced an evolutionary growth spurt, tripling in size. And scientists haven’t had any concrete idea why, Wired reports.

A study published in the journal Proceedings of the Royal Society B might help change that. Researchers examined fossil records and studied phylogenetic models (evolutionary relationships) among baleen whales, and found some evidence that climate change may have been the catalyst for turning the large animals into behemoths.

As the ice ages wore on and oceans were receiving nutrient-rich runoff, the whales encountered an increasing number of krill—the small, shrimp-like creatures that provided a food source—resulting from upwelling waters. The more they ate, the more they grew, and their bodies adapted over time. Their mouths grew larger and their fat stores increased, helping them to fuel longer migrations to additional food-enriched areas. Today blue whales eat up to four tons of krill every day.

If climate change set the ancestors of the blue whale on the path to its enormous size today, the study invites the question of what it might do to them in the future. Changes in ocean currents or temperature could alter the amount of available nutrients to whales, cutting off their food supply. With demand for whale oil in the 1900s having already dented their numbers, scientists are hoping that further shifts in their oceanic ecosystem won’t relegate them to history.

[h/t Wired]