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Why Do Birds Fly South for the Winter?

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Around this time of year, I always have to take a break from pumpkin planning and marvel at bird migration. How do they find their way around the world without Google Maps? We're not really sure, but research has given us evidence that they use an array of navigation techniques...

1. Migratory reflex and navigational skills appear to be written in the genes. Captive birds have been observed getting pretty fidgety and changing their sleep patterns right before their natural migration time. Ethologists—those who study animal behavior—call the birds' behavior zugunruhe ("migratory restlessness"). Captive birds display zugunruhe even if they're not exposed to natural light or to seasonal temperature changes. Even with the restlessness, many of these birds will orient themselves in the direction that they would normally be traveling at that time of year. Researchers say that the fact that the birds know both when and where to migrate without environmental clues suggests that genes, and a biological calendar written into them, play a role in migration.

2. Genes are all well and good to get them started, but how do birds navigate once they get up in the air? The prevailing theory is that the earth's magnetic field plays a large part. Over the last few years, scientists have discovered tiny bits of magnetite (a magnetic mineral) in the brains of several animal species, including birds, bats, whales and dolphins. The magnetite could enable the animals to use the earth's magnetic fields as a migration guide, but the research is just scratching the surface. Now that we know that birds and other animals could detect magnetic fields and have explored the mechanisms by which they could do it, further research will need to tackle the question of how the animals gather information from the magnetic field, process it and use it to navigate.

3. A particularly cool study showed that migratory birds also use "celestial navigation" to find their way around in the dark. Captive birds placed in a planetarium changed their directional orientation when the star pattern on the ceiling shifted and became confused when the images of stars were dimmed. The scientists conducting the experiment suggest that birds use the layout of constellations in the sky as a compass.

But why migrate in the first place? And why do birds bother flying back north once they've reached a warmer locale? The same reason I have to pull myself away from writing and go to the bodega on the corner: the search for food. While birds might be hard-wired to migrate at certain times of the year, a recent study concluded birds won't make the trip without certain physiological and environmental cues, the most important being the scarcity of food. Birds fly south in the winter in search of alternate food sources, and even though their summer home might be nicer, they return home in the spring when their usual food stocks are replenished. If there's still food to be had at either place, though, some birds will delay migration or won't bother leaving at all, choosing instead to band together in flocks to forage.

This article originally appeared last fall.

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iStock // Ekaterina Minaeva
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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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Nick Briggs/Comic Relief
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What Happened to Jamie and Aurelia From Love Actually?
May 26, 2017
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Nick Briggs/Comic Relief

Fans of the romantic-comedy Love Actually recently got a bonus reunion in the form of Red Nose Day Actually, a short charity special that gave audiences a peek at where their favorite characters ended up almost 15 years later.

One of the most improbable pairings from the original film was between Jamie (Colin Firth) and Aurelia (Lúcia Moniz), who fell in love despite almost no shared vocabulary. Jamie is English, and Aurelia is Portuguese, and they know just enough of each other’s native tongues for Jamie to propose and Aurelia to accept.

A decade and a half on, they have both improved their knowledge of each other’s languages—if not perfectly, in Jamie’s case. But apparently, their love is much stronger than his grasp on Portuguese grammar, because they’ve got three bilingual kids and another on the way. (And still enjoy having important romantic moments in the car.)

In 2015, Love Actually script editor Emma Freud revealed via Twitter what happened between Karen and Harry (Emma Thompson and Alan Rickman, who passed away last year). Most of the other couples get happy endings in the short—even if Hugh Grant's character hasn't gotten any better at dancing.

[h/t TV Guide]

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