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Le Monde puzzle [41]

October 17, 2010
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Le Monde puzzle [41]

The current puzzle in Le Monde this week is again about prime numbers: The control key on a credit card is an integer η(a) associated with the card number a such that, if the card number is c=ab, its key η(c) satisfies η(c)=η(a)+η(b)-1. There is only one number with a key equal to 1 and

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Boundary conditions Dominate

October 16, 2010
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Boundary conditions Dominate

In part 1 and part 2 we went over the background of nightlights and the fundamental problem: Station inventory data had errors in it: In Hansen 2010, Hansen writes: “ Station location in the meteorological data records is provided with a resolution of 0.01 degrees of latitude and longitude, corresponding to a distance of about 1

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Accuracy in Inventories and Nightlights Part II

October 16, 2010
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Accuracy in Inventories and Nightlights Part II

In part 1 we discussed UHI in a general way and introduced NASA’s use of nightlights to identify Rural, periurban and Urban stations. Very simply, the latitude and longitude data in the station inventory is used to look up at radiance value in the nightlights file. If that value is  10 or less, the site

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Benoit Mandelbrot (the Father of Fractals) dead at 85

October 16, 2010
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Benoit Mandelbrot (the Father of Fractals) dead at 85

Nicholas Taleb and Recent tweets indicate that Benoit Mandelbrot has died at age 85.  Mandelbrot was a French and American mathematician, best known as the father of fractal geometry.  His official biography at Yale does n...

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Benoit Mandelbrot (the Father of Fractals) dead at 85

October 16, 2010
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Benoit Mandelbrot (the Father of Fractals) dead at 85

Nicholas Taleb and Recent tweets indicate that Benoit Mandelbrot has died at age 85.  Mandelbrot was a French and American mathematician, best known as the father of fractal geometry.  His official biography at Yale does n...

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Margin of error, and comparing proportions in the same sample

October 15, 2010
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Margin of error, and comparing proportions in the same sample

I recently tried to answer a simple question, asked by @adelaigue. Actually, I thought that the answer would be obvious... but it is a little bit more compexe than what I thought. In a recent pool about elections in Brazil, it was mentionned in a ...

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Nightlights: First Principles

October 15, 2010
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Nightlights: First Principles

With the publication of Hansen2010 forthcoming it is critical to examine the subject afresh. The global temperature index product from NASA is known as GISSTEMP .GISSTEMP, like the temperature index from Hadley/CRU and NCDC attempts to estimate the average temperature of the globe using historical data archived in the GHCN ( Global Climate Historical Network)

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Nightlights: cool data, bad geocoding

October 14, 2010
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Nightlights: cool data, bad geocoding

A global source of population density has been on my low-priority wish list for some time, so I was very excited when I found Steve Mosher’s work with the Nighlights data set. “Nightlights” refers to the artificial lights seen from space at night. Astronomers call it “light pollution” which is pretty accurate since it’s decidedly

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Postdoc position in computational Bayesian statistics

October 14, 2010
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Postdoc position in computational Bayesian statistics

Here is an announcement I received that should interest potential postdocs (willing to come to Paris). The location is on the Orsay campus, south of Paris. In the framework of the ANR-funded Metacoli project which aims at identifying the metabolic underpinnings of the lifestyle diversity in the E. coli species, Genoscope (the genomics institute of

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Kuwait Airport

October 14, 2010
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Kuwait Airport

  Kuwait International airport. Giss has it as nightlights =0, so do I. By looking at comparisons of nightlights with the station centered and a static google map with the station centered, there are mismatches between GISS and Me and between Nightlights and the  world. Subtle shift here and there. Annoying. Also, you can see

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