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E é isto

21.06.13

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A descoberta do ano

19.06.13

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"My lungs aren't the way they should be"

16.06.13

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Boys will be boys

14.06.13

 

The drawings from Novgorod that we have found appear to all come from a Russian boy named Onfim, who lived at the end of the twelfth century or beginning of the thirteenth century in the city of Novgorod. By the estimate of the archaeologists who unearthed his works, he was around seven years old at the time that he made these drawings.

 

 

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"How the Robots Lost: High-Frequency Trading's Rise and Fall"

07.06.13

 

 

One of HFT’s objectives has always been to make the market more efficient. Speed traders have done such an excellent job of wringing waste out of buying and selling stocks that they’re having a hard time making money themselves. HFT also lacks the two things it needs the most: trading volume and price volatility. Compared with the deep, choppy waters of 2009 and 2010, the stock market is now a shallow, placid pool. Trading volumes in U.S. equities are around 6 billion shares a day, roughly where they were in 2006. Volatility, a measure of the extent to which a share’s price jumps around, is about half what it was a few years ago. By seeking out price disparities across assets and exchanges, speed traders ensure that when things do get out of whack, they’re quickly brought back into harmony. As a result, they tamp down volatility, suffocating their two most common strategies: market making and statistical arbitrage.

(...)

As profits have shrunk, more HFT firms are resorting to something called momentum trading. Using methods similar to what Swanson helped pioneer 25 years ago, momentum traders sense the way the market is going and bet big. It can be lucrative, and it comes with enormous risks. Other HFTs are using sophisticated programs to analyze news wires and headlines to get their returns. A few are even scanning Twitter feeds, as evidenced by the sudden selloff that followed the Associated Press’s hacked Twitter account reporting explosions at the White House on April 23. In many ways, it was the best they could do.

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"The Limits of Physics"

05.06.13

 

 In the 30 years since I was a student, physicists’ interpretations of their field have increasingly tended toward literalism, while the humanities have tilted towards postmodernism. Thus a kind of stalemate has ensued. Neither side seems inclined to contemplate more nuanced views. It is hard to see ways out of this tunnel, but in the work of the late British anthropologist Mary Douglas I believe we can find a tool for thinking about some of these questions.

On the surface, Douglas’s great book Purity and Danger (1966) would seem to have nothing do with physics; it is an inquiry into the nature of dirt and cleanliness in cultures across the globe. Douglas studied taboo rituals that deal with the unclean, but her book ends with a far-reaching thesis about human language and the limits of all language systems. Given that physics is couched in the language-system of mathematics, her argument is worth considering here.

In a nutshell, Douglas notes that all languages parse the world into categories; in English, for instance, we call some things ‘mammals’ and other things ‘lizards’ and have no trouble recognising the two separate groups. Yet there are some things that do not fit neatly into either category: the pangolin, or scaly anteater, for example. Though pangolins are warm-blooded like mammals and birth their young, they have armoured bodies like some kind of bizarre lizard. Such definitional monstrosities are not just a feature of English. Douglas notes that all category systems contain liminal confusions, and she proposes that such ambiguity is the essence of what is seen to be impure or unclean.

Whatever doesn’t parse neatly in a given linguistic system can become a source of anxiety to the culture that speaks this language, calling forth special ritual acts whose function, Douglas argues, is actually to acknowledge the limits of language itself. In the Lele culture of the Congo, for example, this epistemological confrontation takes place around a special cult of the pangolin, whose initiates ritualistically eat the abominable animal, thereby sacralising it and processing its ‘dirt’ for the entire society.

‘Powers are attributed to any structure of ideas,’ Douglas writes. We all tend to think that our categories of understanding are necessarily real. ‘The yearning for rigidity is in us all,’ she continues. ‘It is part of our human condition to long for hard lines and clear concepts’. Yet when we have them, she says, ‘we have to either face the fact that some realities elude them, or else blind ourselves to the inadequacy of the concepts’. It is not just the Lele who cannot parse the pangolin: biologists are still arguing about where it belongs on the genetic tree of life.

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It's Nick Cave's world, we just live in it

05.06.13

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