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  • feedwordpress 08:01:44 on 2015/06/18 Permalink
    Tags: cats, flaiing cats, , James Clerk Maxwell, , , , , Virgil Foster   

    “In ancient times cats were worshipped as gods; they have not forgotten this”*… 

     

    Certain scientific circles of the nineteenth century were home to a rather unexpected preoccupation: the dropping of cats. While at university in Trinity College, Cambridge, James Clerk Maxwell, who would go onto become arguably the greatest theoretical physicist of the nineteenth century, was reportedly well known for the activity. In a letter to his wife reflecting on this reputation he’d earned, Maxwell wrote, “There is a tradition in Trinity that when I was here I discovered a method of throwing a cat so as not to light on its feet, and that I used to throw cats out of windows. I had to explain that the proper object of research was to find how quick the cat would turn round, and that the proper method was to let the cat drop on a table or bed from about two inches, and that even then the cat lights on her feet.” He was not the only prominent scientist to be intrigued by the question of how cats, when falling from a height, seemingly were able to defy the laws of Newtonian physics and change motion in mid air to land on their feet. At around the same time, the eminent mathematician George Stokes was also prone to a spot of “cat-turning”. As his daughter relates in a 1907 memoir: “He was much interested, as also was Prof. Clerk Maxwell about the same time, in cat-turning, a word invented to describe the way in which a cat manages to fall upon her feet if you hold her by the four feet and drop her, back downwards, close to the floor.”

    Despite the many falling cats, neither Maxwell nor Stokes made much headway in their investigations. It wasn’t until some decades later, with the invention of chronophotography (which allowed many photographs to be taken in quick succession), that a more rigorous study could be applied beyond the limitations of the human eye. The man to do it was the French scientist and photographer Étienne-Jules Marey who in 1894 created a series of images from which he was able to make some important deductions. The images pictured below, captured at 12 frames per second, debunked the idea that the cat was using the dropper’s hand as a fulcrum in order to begin the motion of turning at the beginning of the fall. Rather, the pictures showed that the cat had no rotational motion at the start of its descent and so was somehow acquiring angular momentum while in free-fall. Marey published these pictures, and his investigations, in an 1894 issue of Comptes Rendus, with a summary of his findings published in the journal Nature in the same year. The latter summarises Marey’s thoughts as follows:

    M. Marey thinks that it is the inertia of its own mass that the cat uses to right itself. The torsion couple which produces the action of the muscles of the vertebra acts at first on the forelegs, which have a very small motion of inertia on account of the front feet being foreshortened and pressed against the neck. The hind legs, however, being stretched out and almost perpendicular to the axis of the body, possesses a moment of inertia which opposes motion in the opposite direction to that which the torsion couple tends to produce. In the second phase of the action, the attitude of the feet is reversed, and it is the inertia of the forepart that furnishes a fulcrum for the rotation of the rear.

    In a rather humorous turn the author of the article also states that “The expression of offended dignity shown by the cat at the end of the first series indicates a want of interest in scientific investigation.”…

    See the series of photos and read the whole account at “Photographs of a Falling Cat (1894)“; and see how the riddle was finally solved, 70 years later, Kane and Scher’s 1969 paper “A dynamical explanation of the falling cat phenomenon” (and in this Wikipedia article).

    * Terry Pratchett

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    As we adjust our attitudes, we might recall that it was on this date in 1993 that the first lab test was released in Arizona confirming a bee involved in a fatal on attack on a small dog at a Tucson home was an Africanized honey bee. Because of their more intense defensive swarming behavior, such non-native bees earned the name “killer bee” in the media.

    Arizona was the second state to be invaded, less than three years after this species spread north into Texas from Mexico. Six years later, the bees claimed their first human victim in California: Virgil Foster, an 83-year-old bee-keeper, was mowing his lawn in Los Angeles County when he was stung at least 50 times by the highly-aggressive bees.  Foster’s three hives had been taken over by wild Africanized honey bees. Originally hybridized in Brazil in the 1950s in attempt to increase honey production, the killer bees had migrated north through Central America.

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  • feedwordpress 08:01:08 on 2014/07/11 Permalink
    Tags: Alchian-Allen theorem, , , , cats, , , , , ,   

    “In economics, the majority is always wrong”*… 

     

    “Grumpy Cat,” whose image has flown across the internet– and graced the front page of the Wall Street Journal

    One may imagine that economics has little bearing on the more frivolous frontiers of everyday life; but in fact it explains why one consumes so much “animal antics” online and so little Shakespearean seriousness…

    Economics sometimes has surprising applications. One example is the Alchian-Allen theorem, an observation that came from a footnote in an economics textbook in the 1960s about how quality demand is affected by transport costs…

    The Allen-Alchian theorem explains why places with high-quality produce (Allen and Alchian had in mind apples in Seattle, which is where apples come from in the US) nevertheless do not always get to consume that same high quality (they pointed to the market for apples in New York city, where no apples grow) because of the relative costs faced by consumers in each case (for New York consumers, a high-quality apple, once you account for transportation costs, was actually relatively cheaper than a low-quality apple compared to relative prices in Seattle). Hence the market sent the high-quality apples to New York.

    You’re still with me? It’s all about relative costs. When you move something, or impose any fixed cost, the higher-quality item always wins, because it now has a lower relative cost compared to the lower-quality item.

    The interesting idea is that this also applies in reverse – namely when we remove a fixed cost. The internet does this: it removes a cost of transport, and it does so equally for high quality and low quality content. Following the Allen-Alchian theorem, this should mean the opposite. Low-quality items are now relatively cheaper and high-quality items are now relatively more expensive. This idea was first explained by Tyler Cowen, but the upshot is that the internet is made of cats

    The internet lowers the cost of “transport” for every idea, high and low quality alike. It’s the opposite of the apples situation. It means that low quality apples are now relatively cheaper. It means that cats-doing-funny-things is now relatively cheaper than say German Opera. Economics insists that when demand curves look like this we can expect more cat watching, and less German opera watching.

    This theorem means that we expect a lower quality, “bittier” consumption to proliferate on the internet (as a technology that lowers transport costs of high-quality and low-quality ideas alike). Which is what we observe. So that’s a win for micro-economic demand theory.

    Is this really what’s happened?  Have we all gotten dumber?  Read more– including the arguments, pro and con– at “The internet is made of cats – and you can blame economists“: and read the paper the lays out the “economics of cute” in “The Alchian-Allen Theorem and the Economics of Internet Animals.”

    * John Kenneth Galbraith

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    As we come to terms with the fact that all our bases are belong to them, we might spare a slightly skewed thought for Giuseppe Arcimboldo; he died on this date in 1593.  An Italian painter best known for creating partraits composed entirely of such objects as fruits, vegetables, flowers, fish, and books, he is considered a Mannerist… though he might well be the first Surrealist.  He was certainly cited by many– from Dali through Ocampo to Švankmajer– as an influence.

    Arcimboldo’s portrait of Rudolf II, Holy Roman Emperor, painted as Vertumnus, the Roman God of the seasons, c. 1590-1

    source

    Self-portrait

    source

     

     
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