elements

Don’t let go of me (Grip my hips and move me)

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Why do fingers get wrinkly in the water? […]

A hypothesis has been proposed which suggests that the wrinkling might be an evolutionary adaptation to make the handling of objects underwater easier. Wrinkling creates a kind of drainage path for water and so enhances the grip on an object (this is called a ‘rain tread’ hypothesis). In order to test if this hypothesis is true Kareklas et al. have recruited volunteers and tested their ability to transfer wet objects when the fingers are wrinkled and not. […]

20 participants had to transfer glass marbles from one container to another in two different conditions (1) take the marble from a container with water pass it through a small hole and put into an empty container and (2) take the marble from a container without water pass it through a small hole and put into an empty container. […]

When the marble ball was dry there was no difference between the transfer time with wrinkly and smooth fingers. However, when the marble was wet then on average it took 12% less time to transfer the object with wrinkly fingers. Therefore, the study concluded that the wrinkling of fingers improves the handling of wet objects (which supports the rain tread hypothesis). Why are our fingers not always wrinkled then? In paper’s discussion Kareklas et al. suggest that there potentially are some fitness trade-offs to the wrinkly fingers. Maybe wrinkled fingers are less sensitive to pain, pressure, heat etc. and are therefore damaged easier, which would explain why it is not good to always have those wrinkles.

{ The Question Gene | Continue reading }

The work done in this room lies at the heart of a department that handles some of the UK’s most cutting-edge research on forensics and anatomy. […]

The hand is Meadows’ area of focus. Variations in scars, skin pigmentation, the smallest nooks and crannies of the fingernail and, most importantly, superficial vein patterns: all of these can build a body of evidence and allow the police to identify an offender in an incriminating photograph. “The back of the hand is part of the anatomy that an offender is quite happy to have in an image, whereas they wouldn’t necessarily want their face captured,” Meadows says. In 2009, Cahid’s work was instrumental in the Neil Strachan case, part of Scotland’s biggest paedophile ring. His unusually distorted lunula (the white half moon at the bottom of a nail) helped identify and convict him.

Meadows and her colleagues have built up the UK’s only database of the hand’s vein patterns, with around 800 samples. Of the 40 or so cases they have worked on, their data have resulted in over 80 per cent of suspects changing their plea.

{ FT | Continue reading }

Wendy, darling, light of my life

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Researchers are a step closer to demonstrating that explosives – rather than water – could be used to extinguish an out-of-control bushfire.

Dr Graham Doig, of the School of Mechanical and Manufacturing Engineering, is conducting the research, which extends a long-standing technique used to put out oil well fires.

The process is not dissimilar to blowing out a candle: it relies on a blast of air to knock a flame off its fuel source.

{ University of New South Wales | Continue reading }

‘In practical life we are compelled to follow what is most probable ; in speculative thought we are compelled to follow truth.’ —Spinoza

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When a coin falls in water, its trajectory is one of four types determined by its dimensionless moment of inertia I∗ and Reynolds number Re: (A) steady; (B) fluttering; (C) chaotic; or (D) tumbling. The dynamics induced by the interaction of the water with the surface of the coin, however, makes the exact landing site difficult to predict a priori.

Here, we describe a carefully designed experiment in which a coin is dropped repeatedly in water to determine the probability density functions (pdf) associated with the landing positions for each of the four trajectory types, all of which are radially symmetric about the centre drop-line.

{ arXiv | PDF }

‘It takes two people to make you, and one people to die. That’s how the world is going to end.’ —Faulkner

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Over half a century ago, the global economy largely depended on just ten or so different materials. Most important products were made out of wood, brick, iron, copper, gold, silver or a few plastics — and that was about it.

Things are wildly different today. A huge chunk of modern-day technology, from hybrid cars to iPhones to flat-screen TVs to radiation screens, use dozens of different metals and alloys. A computer chip typically involves more than 60 different elements that are specifically selected to optimize performance, like europium or dysprosium.

And that’s long raised a concern: What would happen if we run short of any of these valuable metals? Say there’s a war. Or unrest in a crucial mining region. Or China decides to lock up its strontium deposits. Could we easily come up with substitutes? Or is modern society vulnerable to a materials shortage?
Here’s the case for vulnerability: A fascinating recent paper in The Proceedings of the National Academies of Science looks at 62 different metals that are widely used in modern-day industry. For a dozen metals, potential substitutes are either inadequate or flat-out unavailable. And there are no “excellent” substitutes for any of the 62 metals.

{ Washington Post | Continue reading }

art { Robert Indiana, The X-5, 1963 }

The sadness will last forever

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There are many theories about why humans cry ranging from the biophysical to the evolutionary. One of the most compelling hypotheses is Jeffrey Kottler’s, discussed at length in his 1996 book The Language of Tears. Kottler believes that humans cry because, unlike every other animal, we take years and years to be able to fend for ourselves. Until that time, we need a behavior that can elicit the sympathetic consideration of our needs from those around us who are more capable (read: adults). We can’t just yell for help though—that would alert predators to helpless prey—so instead, we’ve developed a silent scream: we tear up. […]

In a study published in 2000, Vingerhoets and a team of researchers found that adults, unlike children, rarely cry in public. They wait until they’re in the privacy of their homes—when they are alone or, at most, in the company of one other adult. On the face of it, the “crying-as-communication” hypothesis does not fully hold up, and it certainly doesn’t explain why we cry when we’re alone, or in an airplane surrounded by strangers we have no connection to. […]

In the same 2000 study, Vingerhoet’s team also discovered that, in adults, crying is most likely to follow a few specific antecedents. When asked to choose from a wide range of reasons for recent spells of crying, participants in the study chose “separation” or “rejection” far more often than other options, which included things like “pain and injury” and “criticism.” Also of note is that, of those who answered “rejection,” the most common subcategory selected was “loneliness.”

{ The Atlantic | Continue reading }

photo { Adrienne Grunwald }

The ox is slow, but the earth is patient

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First, about how glaciers turn into ocean water.

Consider this experiment. Take a large open-top drum of water and poke a hole near the bottom. Measure the rate at which water comes out of the hole. As the amount of water in the drum goes down, the rate of flow out of the hole will normally decrease because the amount of water pressure behind the hole decreases. Now, have a look at a traditional hourglass, where sand runs from an upper chamber which slowly empties into a lower chamber which slowly fills. If you measure the rate of sand flow through the connecting hole, does it decrease in flow rate because there is, over time, less sand in the upper chamber? I’ll save you the trouble of carrying out the experiment. No, it does not. This is because the movement of sand from the upper to lower parts of an hourglass is an entirely different kind of phenomenon than the flow of water out of the drum. The former is a matter of granular material dynamics, the latter of fluid dynamics.

Jeremy Bassis and Suzanne Jacobs have recently published a study that looks at glacial ice as a granular material, modeling the ice as clumped together ice boulders that interact with each other either by sticking together or, over time, coming apart at fracture lines. This is important because, according to Bassis, about half of the water that continental glaciers provide to the ocean comes in the form of ice melting (with the water running off) but the other half consists of large chunks (icebergs) that come off in a manner that has been very hard to model.

{ Greg Laden/ScienceBlogs | Continue reading }

What’s to be expected is 3 minus

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The unavoidable truth is that sea levels are rising and Miami is on its way to becoming an American Atlantis. It may be another century before the city is completely underwater (though some more-pessimistic­ scientists predict it could be much sooner), but life in the vibrant metropolis of 5.5 million people will begin to dissolve much quicker, most likely within a few decades. […]

South Florida is not the only place that will be devastated by sea-level rise. London, Boston, New York and Shanghai are all vulnerable, as are low-lying underdeveloped nations like Bangladesh. But South Florida is uniquely screwed, in part because about 75 percent of the 5.5 million people in South Florida live along the coast. And unlike many cities, where the wealth congregates in the hills, southern Florida’s most valuable real estate is right on the water.

{ Rolling Stones | Continue reading }

related { Global warming has slowed. The rate of warming of over the past 15 years has been lower than that of the preceding 20 years. There is no serious doubt that our planet continues to heat, but it has heated less than most climate scientists had predicted. | The Economist }

In the water of a pure stream, a fasting wolf came by, looking for something

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Hurricane Sandy was the largest storm to hit the northeast U.S. in recorded history, killing 159, knocking out power to millions, and causing $70 billion in damage in eight states. Sandy also put the vulnerability of critical infrastructure in stark relief by paralyzing subways, trains, road and air traffic, flooding hospitals, crippling electrical substations, and shutting down power and water to tens of millions of people. But one of the larger infrastructure failures is less appreciated: sewage overflow.

Six months after Sandy, data from the eight hardest hit states shows that 11 billion gallons of untreated and partially treated sewage flowed into rivers, bays, canals, and in some cases, city streets, largely as a result of record storm-surge flooding that swamped the region’s major sewage treatment facilities. To put that in perspective, 11 billion gallons is equal to New York’s Central Park stacked 41 feet high with sewage, or more than 50 times the BP Deepwater Horizon oil spill. The vast majority of that sewage flowed into the waters of New York City and northern New Jersey in the days and weeks during and after the storm.

{ Climate Central | PDF }

‘Those who don’t drink and aren’t crazy, or who don’t attract attention with how they behave in public, aren’t noticed in art.’ –Georg Baselitz

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{ Thanks Tim }

its metamorphoses as vapour, mist, cloud, rain, sleet, snow, hail: its strength in rigid hydrants: its variety of forms in loughs and bays and gulfs and bights and guts and lagoons and atolls and archipelagos and sounds and fjords and minches and tidal estuaries and arms of sea

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Scientists think that they have the answer to why the skin on human fingers and toes shrivels up like an old prune when we soak in the bath. Laboratory tests confirmed a theory that wrinkly fingers improve our grip on wet or submerged objects, working to channel away the water like the rain treads in car tyres. […]

Wrinkled fingers could have helped our ancestors to gather food from wet vegetation or streams, Smulders adds. The analogous effect in the toes could help us to get a better footing in the rain.

{ Nature | Continue reading }

Stick a fork in it

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A thousand years ago, the Doge Pietro Orseolo II took his triumphant naval fleet to the sea entrance at the Lido and ceremoniously threw a diamond ring into the water, thus marrying his city to the Adriatic and securing Venice’s dominion over its waters and trade routes. […]

When Goethe visited Venice for just over two weeks in 1786, he climbed the campanile twice, at high tide and then at low tide. It was from this tower that, at the age of 37 and already famous, he saw the sea for the first time in his life. […]

Now we know for sure that the ocean is rising faster than Venice will subside.

{ Aeon | Continue reading }

photo { Roman Noven and Tania Shcheglova }

Was the guest conscious of and did he acknowledge these marks of hospitality?

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Once in our history, the world-wide population of human beings skidded so sharply we were down to roughly a thousand reproductive adults. One study says we hit as low as 40. […] around 70,000 B.C., a volcano called Toba, on Sumatra, in Indonesia went off, blowing roughly 650 miles of vaporized rock into the air. It is the largest volcanic eruption we know of, dwarfing everything else… […] With so much ash, dust and vapor in the air, Sam Kean says it’s a safe guess that Toba “dimmed the sun for six years, disrupted seasonal rains, choked off streams and scattered whole cubic miles of hot ash (imagine wading through a giant ashtray) across acres and acres of plants.” Berries, fruits, trees, African game became scarce; early humans, living in East Africa just across the Indian Ocean from Mount Toba, probably starved, or at least, he says, “It’s not hard to imagine the population plummeting.”

Then — and this is more a conjectural, based on arguable evidence — an already cool Earth got colder. The world was having an ice age 70,000 years ago, and all that dust hanging in the atmosphere may have bounced warming sunshine back into space. So we almost vanished. […]

It took almost 200,000 years to reach our first billion (that was in 1804), but now we’re on a fantastic growth spurt, to 3 billion by 1960, another billion almost every 13 years since then.

{ NPR | Continue reading }