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Photo: sewitsforyou

Drop an S-bomb today in polite conversation, and heads will likely turn. But back in the ninth century, “shit” referred to excrement in a matter-of-fact, not a vulgar, way. In the new book Holy Sh*t: A Brief History of Swearing, author Melissa Mohr explores how our opinion of this and other curse words have shifted over the years. In an interview with NPR, she delves into the history of “shit”:

It only really started to become obscene, I would say, during the Renaissance. … It basically involves increasing privacy. In the Middle Ages … when that word wasn’t obscene, people lived very differently. The way their houses were set up, there wasn’t space to perform a lot of bodily functions in private. So they would defecate in public, they had privies with many seats, and it was thought to be a social activity. That you would all get together on the privy and talk while you did this. … As the actual act became more taboo because you could do it in private now … the direct word became taboo.

The word itself likely arose from one or all of the Old English terms scite (dung), scitte (diarrhea) or scitan (to defecate). Middle English introduced schitte (excrement), schyt (diarrhea) and shiten (to defecate). Similar terms for the same thing eventually found their way into other languages as well, such as Sheisse (german), schijt (Dutch), skit (Swedish), skitur (Icelandic) and skitt (Norwgian).

As the Online Etymology Dictionary details, “shit” as a term related to excrement dates to at least the 1580s, though people had already adopted the term in reference for an “obnoxious person” by at least 1508.

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Why do we LOL? Is ROFLing an innate piece of human behavior? Does our tendency to LMAO say something about us—something that separates us from the non-kekekeing species who share our planet?

For Scienceline, William Herkewitz explores the evolutionary history of laughter, a story that shows us that maybe we’re not quite so unique as we’d like to think. It’s not just that we laugh at funny things. The roots of this behavior, scientists think, go back much further and actually play an important purpose.

Herkewitz finds that various theories abound, but that the current “best guess” says that humans laugh to tell other humans not to get too fussed over something that could otherwise be regarded as scary or dangerous.

If you’re an ancestral human, says Ramachandran, and you come across what you think is a dangerous snake but actually turns out to be a stick, you’re relieved and you laugh. “By laughing, you’re communicating: ‘All is OK,’” says Ramachandran.

Ramachandran believes the “false alarm” signaling purpose of laugher explains its loud sound and explosive quality. If you want to signal something to a larger social group, they better hear it. His theory also helps explain the contagiousness of laughter — a curious quality exploited by the laugh tracks of TV sitcoms. Strangely enough, hearing the sound of laughter, on its own, is enough to elicit more laughter in others. “A signal is much more valuable if it amplifies and spreads like wildfire in the group,” says Ramachandran.

People also laugh to show pleasure, to bond with other members of the group. And in this regard, humans’ laughter isn’t special.

Our laughter, the Tommy gun staccato sound of “ha-ha-ha,” is unique in the animal kingdom. Beyond scientific anomalies like Mister Ed or Babe the pig, if you visit your local zoo you’ll be hard-pressed to find any animals making a sound you’d confuse with human laughter. But do humans, in the vast gallery of life, laugh alone? Ask Jaak Panksepp, a neuroscientist and veterinarian at the University of Washington, and he’ll tell you no. Panksepp studies laughter where you might least expect it, in lab rats.

“In the mid 1990’s we found [rats] have a sound — a high-pitched chirp — that they made most often during play,” says Panksepp. “It crossed my mind it might be an ancestral form of laughter.” And Panksepp, eager to investigate, dove hands-first into his theory. He tickled his rats.

What he found lead to two decades of research. “They’re just like little children when you tickle them,” says Panksepp. “They ‘love’ it.”

Dogs, too, laugh in their own way. As do primates. The work is a reminder that for all that humans are, and all the things we do, there’s actually very little that makes us special.

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Dunwich beach, across which storms pulled the ancient city. Image: modagoo

In 1066, the town of Dunwich began its march into the sea. After storms swept the farmland out for twenty years, the houses and buildings went in 1328. By 1570, nearly a quarter of the town had been swallowed, and in 1919 the All Saints church disappeared over the cliff. Dunwich is often called Britain’s Atlantis, a medieval town accessible only to divers, sitting quietly at the bottom of the ocean off the British Coast.

Now, researchers have created a 3D visualization of Dunwich using acoustic imaging. David Sear, a professor at the University of Southampton, where the work was done, described the process:

Visibility under the water at Dunwich is very poor due to the muddy water. This has limited the exploration of the site. We have now dived on the site using high resolution DIDSON ™ acoustic imaging to examine the ruins on the seabed – a first use of this technology for non-wreck marine archaeology.

DIDSON technology is rather like shining a torch onto the seabed, only using sound instead of light. The data produced helps us to not only see the ruins, but also understand more about how they interact with the tidal currents and sea bed.

Using this technology gives them a good picture of what the town actually looks like. Ars Technica writes:

We can now see where the local churches stood, and crumbling walls pinpoint the ancient town’s remits. A one kilometer (0.6 mile) square stronghold stood in the center of the 1.8km2space (about 0.7 square miles), with what looks like the remains of Blackfriars Friary, three churches, and the Chapel of St Katherine standing within it. The northern region looks like the commercial hub with lots of smaller buildings largely made of wood. It’s thought that the stronghold, as well as its buildings and a possible town hall, may date back to Saxon times.

Professor Sears sees this project as not just one of historical and archaeological importance, but also as a forecast of the fate of seaside cities. “It is a sobering example of the relentless force of nature on our island coastline. It starkly demonstrates how rapidly the coast can change, even when protected by its inhabitants. Global climate change has made coastal erosion a topical issue in the 21st Century, but Dunwich demonstrates that it has happened before. The severe storms of the 13th and 14th Centuries coincided with a period of climate change, turning the warmer medieval climatic optimum into what we call the Little Ice Age.”

So, in a million years, when aliens come to look at our planet, it might look a lot like Dunwich.

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Image: Rosie O’Beirn

Every so often you hear about the oldest person in the world dying. On April 1st, Elsi Calvert Thompson, America’s oldest person, died at 114. On December 17th, 2012, the 115-year-old Dina Mandredini passed away, handing off the world’s oldest living person title to Besse Cooper. But how often does the world’s oldest person die?

Here’s what that question looks like to a mathematician:

If you live in a country with Ncountry people, a continent with Ncontinent people and a world with Nworld people, during a year and on average, how often will you be notified (if you’re paying attention to your quality tabloid) of the death of the oldest man/woman/person alive of your country/continent/world? (Note that a death will result in at most one notification.)

On Stackexchange, which calls itself “a question and answer site for people studying math at any level,” Marc van Leeuwen tried to answer that question, and with the help from the community, came up with lots of ways to think about it.

Mortality tables from the CDC, for example, give one answer, provided by Chris Taylor. These tables only go up to 100, and since many of the oldest people crack that ceiling, he had to extrapolate a bit, knowing that the oldest person to have ever lived died at 122.

For each age a, the number of people of age a in year t is the fraction of the population aged a−1 at time t−1 who don’t die, i.e.N(t,a) (1−h(a−1))×N(t−1,a−1)

Eventually, he had an answer:

Taking the total number of events, and dividing by the number of years that I run the simulation for, gives an approximate rate. The punchline is that in my simulation, I see 15,234 events in 10,000 years, for an approximate rate of once in every 0.66 years.

Another person looked to the Gerontology Research Group, who keeps records on the death of the oldest living person. A user named Gwern calculated:

I extracted the final column, death dates, and formatted it and extracted the intervals between the death dates of each person, reasoning that if the Oldest Person In The World who died in 1955 is succeeded by a person who died in 1956, that meant an observer would, in 1955, wait ~1 year for the new Oldest Person to die. The mean interval between deaths turns out to be 1.2 years, but the median wait turns out to be 0.65 years! This seems to be due in large part due to the astounding lifespan of Jeanne Calment, as you will see on the interval graph shortly.

Jean Calment holds that 122-year record. The Gerontology Research Group has images of Jean from age 20 to age 122.

At Stackexchange, a few more people came up with answers, but things seem to settle around one oldest-person death every 0.65 years. Now, obviously, figuring out who the oldest person in the world is, is pretty hard. But since most of us will never hold the title of oldest person in the world, we can at least savor the fact that, for at least a few seconds, we were at one point the youngest.

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Image: Harvard University

Robots get smaller, smarter and faster every day. Now that we can 3-D print the little devices, they’re also easier to make. In fact, they’re so easy to make that there’s one robot that can actually assemble itself.

Here it is, assembling its way to world supremacy:

The materials used here are shape memory polymers. They remember certain shapes and, when the right conditions are met, fold into those forms. This robot can bend itself from a flat sheet into a little worm-like thing. Here’s an explanation of how shape memory works from IEEE Spectrum:

Self-folding happens thanks to shape memory polymers that contract when heated. By printing these polymers on one side of a hinged substrate and then heating them, the hinge can be made to bend. The amount of bend is controlled by etching flexible connectors that connect both sides of the hinge, and with enough hinges heated in the right order, it’s possible to create fairly complex folded shapes, including things like interlocking structural elements.

The tricky part of the process is the folding of the robot itself: installing the battery and motor is trivial enough for a human to do, which means that a relatively simple pick and place robot should have no problems doing the same thing. This means that these robots have the potential to scale massively: they can be printed out of cheap materials, they fold themselves together, and another robot can plonk some hardware on them and they’re good to go.

Now, we’ve seen self assembling robots before. Like this one:

And we’ve seen robots that have been 3-D printed before. Like this one:

But this is the first robot to be both 3-D printed and have the ability to self assemble. Next step: teach them to solder.

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