How to walk on water - updated

YouTube link.

Waxy, hydrophobic coatings typically make such insects’ points of contact (feet, legs, etc.) water-repellent, and their light weight can be supported by surface tension. Navigating the interface between air and water is more complicated, though, and these creatures have evolved several mechanisms to help. Some, like water striders, use appendages they insert below the surface for propulsion. At 0:49 in the montage above, you can see flow visualization of the vortices generated by a stroke. Other insects release a chemical in their wake that lowers the local surface tension and drives them away via the Marangoni effect.

That last-named one is particularly cool; I presume that's what's happening in the segments labeled "meniscus climbing." 

Addendum:  A hat tip to an anonymous reader for sorting out two of the mechanisms.

The Marangoni effect is shown near the end of the video, but I believe the sections labeled "meniscus climbing" are something different. The insects shown are adopting postures that change the shape of the surface of the water around them, causing capillary forces to draw them up to the top of the meniscus. This can be seen in the side views as dents or peaks in the water where the legs touch, or in the top view as bright and dark spots around the legs in the shadow - bright spots where the water is pulled up and focusing light, dark where it is pushed down and diffusing light. The same forces are used as in the capillary attraction two insects use to stick together at 1:03. The water treader Mesovelia (the first one shown climbing the meniscus) is covered with water-repellent hairs, so it uses special claws to grasp the surface of the water for meniscus climbing. 

Here are two relevant links - first to the hard science explanation in the esteemed Nature journal, and to a beautifully illustrated companion piece replete with photos by these same authors.  If this post has stimulated your interest, the second link is totally worth your visit.

Thanks again, anon.





Via fuck yeah fluid dynamics.

"I don't believe in colleges and universities" - updated

From a 2009 New York Times article about Ray Bradbury, then approaching 90 years of age:

"...among Mr. Bradbury’s passions, none burn quite as hot as his lifelong enthusiasm for halls of books. His most famous novel, “Fahrenheit 451,” which concerns book burning, was written on a pay typewriter in the basement of the University of California, Los Angeles, library; his novel “Something Wicked This Way Comes” contains a seminal library scene...

“Libraries raised me,” Mr. Bradbury said. “I don’t believe in colleges and universities. I believe in libraries because most students don’t have any money. When I graduated from high school, it was during the Depression and we had no money. I couldn’t go to college, so I went to the library three days a week for 10 years.”

He is not a fan of the Internet, however: "“It’s distracting,” he continued. “It’s meaningless; it’s not real. It’s in the air somewhere.” More at the link.

Reposted from 2010 to commemorate Bradbury's death today.   Interestingly, I also found Bradbury's sentiment echoed by another SciFi legend, Isaac Asimov:

I received the fundamentals of my education in school, but that was not enough. My real education, the superstructure, the details, the true architecture, I got out of the public library. For an impoverished child whose family could not afford to buy books, the library was the open door to wonder and achievement, and I can never be sufficiently grateful that I had the wit to charge through that door and make the most of it. Now, when I read constantly about the way in which library funds are being cut and cut, I can only think that the door is closing and that American society has found one more way to destroy itself.

Asimov quote via A Writer's Ruminations.

Addendum:  Reposted from 2012 to add this observation by Bradbury on how to use a library:

I use a library the same way I’ve been describing the creative process as a writer — I don’t go in with lists of things to read, I go in blindly and reach up on shelves and take down books and open them and fall in love immediately. And if I don’t fall in love that quickly, shut the book, back on the shelf, find another book, and fall in love with it. You can only go with loves in this life.

And this:

I try to keep up with what’s being done in every field, and most children’s books are ten times more enjoyable than the average American novel right now.

Text from a public television interview in the 1970s, posted at Brain Pickings.

Juxtaposition

"A child waits to unload drums of diesel at a jetty in the Niger Delta, where illicitly refined fuel is sold on the black market to local filling stations."  Photograph: Samuel James

"A boy is supported as he fires a machine gun."   Photograph: Pete Mulle.

Two selections from a gallery of seventeen images from the Sony World photography awards at The Guardian.

One factor that bloats the cost of American health care

From the Washington Post:

Unknown to most, a single committee of the AMA, the chief lobbying group for physicians, meets confidentially every year to come up with values for most of the services a doctor performs.

Those values are required under federal law to be based on the time and intensity of the procedures. The values, in turn, determine what Medicare and most private insurers pay doctors.

But the AMA’s estimates of the time involved in many procedures are exaggerated, sometimes by as much as 100 percent, according to an analysis of doctors’ time, as well as interviews and reviews of medical journals.

If the time estimates are to be believed, some doctors would have to be averaging more than 24 hours a day to perform all of the procedures that they are reporting. This volume of work does not mean these doctors are doing anything wrong. They are just getting paid at the rates set by the government, under the guidance of the AMA...

Florida records show 78 doctors — gastroenterologists, ophthalmologists, orthopedic surgeons and others — who performed at least 24 hours worth of procedures on an average workday.

Some former Medicare chiefs say the problem arises from giving the AMA and specialty societies too much influence over physician pay...

More at the link.

Afghanistan in 1967

In 1967, Professor William Podlich (Arizona State University) took a sabbatical for two years to teach in the College of Teachers in Kabul as part of a collaboration with UNESCO. Besides his teaching activities, Podlich was a prolific photographer, and documented extensively everyday life. For the record, we are a decade before the Soviet invasion (1979).

Back to school for Afghan girls. They were also educated than boys. While in uniform, they were not allowed to wear the burqa to go to school.

Text translated from the original French at Curiosités de Titam.  Galleries of the original photos are at this link.   Note the Paghman Gardens photo location looks a bit different today...

Movie poster cliches

From a gallery of 15 at imgur, via Boing Boing.

Wall Street's bid-rigging conspiracy

Excerpts from a lengthy article by Matt Taibbi at Rolling Stone:

Over 10 years in the making, the case allowed federal prosecutors to make public for the first time the astonishing inner workings of the reigning American crime syndicate, which now operates not out of Little Italy and Las Vegas, but out of Wall Street.
 
The defendants in the case – Dominick Carollo, Steven Goldberg and Peter Grimm – worked for GE Capital, the finance arm of General Electric. Along with virtually every major bank and finance company on Wall Street – not just GE, but J.P. Morgan Chase, Bank of America, UBS, Lehman Brothers, Bear Stearns, Wachovia and more – these three Wall Street wiseguys spent the past decade taking part in a breathtakingly broad scheme to skim billions of dollars from the coffers of cities and small towns across America. The banks achieved this gigantic rip-off by secretly colluding to rig the public bids on municipal bonds, a business worth $3.7 trillion. By conspiring to lower the interest rates that towns earn on these investments, the banks systematically stole from schools, hospitals, libraries and nursing homes – from "virtually every state, district and territory in the United States," according to one settlement. And they did it so cleverly that the victims never even knew they were being ­cheated. No thumbs were broken, and nobody ended up in a landfill in New Jersey, but money disappeared, lots and lots of it, and its manner of disappearance had a familiar name: organized crime.

In fact, stripped of all the camouflaging financial verbiage, the crimes the defendants and their co-conspirators committed were virtually indistinguishable from the kind of thuggery practiced for decades by the Mafia, which has long made manipulation of public bids for things like garbage collection and construction contracts a cornerstone of its business...

More recently, a major international investigation has been launched into the manipulation of Libor, the interbank lending index that is used to calculate global interest rates for products worth more than $3 trillion a year. If and when that case is presented to the public at trial – there are several major civil suits in the works here in the States – we may yet find out that the world's most powerful banks have, for years, been fixing the prices of almost every adjustable-rate vehicle on earth, from mortgages and credit cards to interest-rate swaps and even currencies.

But USA v. Carollo marks the first time we actually got incontrovertible evidence that Wall Street has moved into this cartel-type brand of criminality. It also offered a disgusting glimpse into the enabling and grossly cynical role played by politicians, who took Super Bowl tickets and bribe-stuffed envelopes to look the other way while gangsters raided the public kitty. And though the punishments that were ultimately handed down in the trial – minor convictions of three bit players – felt deeply unsatisfying, it was still a watershed moment in the ongoing story of America's gradual awakening to the realities of financial corruption.

Lots more detail at the link.