CNRS positions 2014: first results

The 2014 campaign for permanent research positions at the CNRS started in December. It involves a first stage, the pre-selection, introduced in 2012. The results are now in for the competitions in some sections (see my older post for the role of the CNRS sections and for the various types of open positions.) They are online here; enter the appropriate competition number and choose the option "Candidates to be interviewed" from the drop-down menu.

The selectivity of this first step has increased since 2012; in the sections corresponding to physical sciences (1-5 and 8-11), about half of all applications (at the CR2 level) were successful, with the exception of section 2, where this number is below 0.3 (there were 185 candidates!) and of section 1, where the pre-selection rate is closer to 3/4, probably because all positions are targeted, so the selection process is pretty much separate (although there is strong overlap between 01/03 and 01/04 and between 01/06 and 01/09).

It seems that each commission selected 40-50 candidates (again, with the exception of section 1, where there are 88 of them and of section 8, with 68). This amounts to 11 applications per open position overall (but to less individual candidates, due to multiple applications between sections.)

The interview dates for each section are available here. Good luck everybody!

Intellectual dichotomies

When trying to understand a particular topic, a criterion for separating all thinkers into two (or a few) classes would be extremely convenient. Here are some striking distinctions:

• Naive and Sentimental poets (according to Schiller). Further applied to novelists by Orhan Pamuk.
• Foxes and Hedgehogs among intellectuals in general (Isaiah Berlin, borrowing from Archilochus).
• Mathematicians can be Birds or Frogs, says Freeman Dyson. 

I believe these categories are memorable because they relate to temperament and thus cut across cultures and ages, unlike more abstract choices, such as Eleatic/Heraclitean, realist/nominalist, ancient/modern (in literature), etc.

More chores = less sex!

[from the NY Times] It's official: when men do more work around the house, the couple has less sex! Now, where is my newspaper ?!

Reflections on The Better Angels of Our Nature - part 1

Since its publication in 2011, The Better Angels of Our Nature has been thoroughly reviewed, with the reactions ranging from enthusiastic to snarkily dismissive. The Wikipedia page does a good job of summarizing the argument and its reception, so there is not much left to add, apart from some personal impressions:

Almost absent from the reviews¹ (although, in my opinion, it is one of the main merits of the book) is the central role played by Norbert Elias and his Civilizing Process.This process is one of the explanations put forward for the spectacular decrease in violence.

The other cause Pinker invokes for the reduction in violence since the Middle Ages (in Europe, at least) is what he calls Enlightenment humanism, or classical liberalism (at the end of Chapter 4). This tradition is not easily defined, as one can see from John Gray's objections that the authors cited by Pinker “are highly disparate thinkers, and it is far from clear that any coherent philosophy could have 'coalesced' from their often incompatible ideas”² and that some of them, such as the French revolutionaries, advocated the use of violence. However:

• The historical evolution of an idea cannot involve homogeneous thinkers (otherwise there would be no evolution). Of course Hobbes and Mill have different positions, but nobody would deny their contribution to liberalism.
• Pinker rejects the idea that the Enlightenment is responsible for the French Revolution and its bloody aftermath (including Napoleon). To prove him wrong, one should at least engage his argument.
• The intellectual contribution of an author is more important than his having held acceptable morals. For instance, some consider Machiavelli a precursor of liberalism.

The very substantial chapter 5 "The Long Peace" discusses whether the reduction in violence since the end of World War II is a systematic effect. The weakest link here is estimating the effects of ancient conflicts, such as the An Lushan revolt in 8th century China, which purportedly killed 36 million people in eight years. This figure corresponds to the difference in census data before and after the rebellion, but the reduction could also be due to loss of territory, refugees, weakening of the administration (leading to less reliable information) etc. On the technical side, Pinker gives an interesting argument that the magnitude of attrition wars is exponentially distributed, but introducing an escalation component can turn the distribution into a power law. I gave the detailed derivation of this result in a previous post.

(to be continued...)

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^{1. Notable exceptions are Peter Singer and James Q. Wilson. ↩}

^{2. In the next phrase, Gray takes Pinker to task for not adding Marx, Bakunin and Lenin to the list. Apart from the intrinsic incoherence of this argument, the point is addressed three pages later, where Pinker explicitly discusses counter-Enlightenment positions, including that of Marx. ↩}

Lucretius and the depletion interaction

In book 6 of On the Nature of Things, Lucretius explains why magnet attracts iron; the picture he draws is very similar to what we now call depletion interaction (due to smaller particles being removed from the gap between larger ones):

First, stream there must from off the lode-stone seeds
Innumerable, a very tide, which smites
By blows that air asunder lying betwixt
The stone and iron. And when is emptied out
This space, and a large place between the two
Is made a void, forthwith the primal germs
Of iron, headlong slipping, fall conjoined
Into the vacuum, and the ring itself
By reason thereof doth follow after and go
Thuswise with all its body. 

(translated by William Ellery Leonard)

Although this theory did not age very well, there is one particular type of electromagnetic interaction (the Casimir force) that resembles it, being essentially photon depletion.

Interpretations of the classical electron radius

The classical electron radius:\begin{equation}
r_{\text{e}} = \frac{1}{4 \pi \epsilon _0}\frac{e^2}{m c^2} \simeq 2.82 \, \text{fm}
\label{eq:redef}
\end{equation}

is usually defined in terms of the electrostatic energy of a charged sphere. The sphere radius is chosen such that, when the total charge equals the elementary one, the energy equals the rest mass of the electron (up to a numerical prefactor).

Hybrid nanocomposites with tunable alignment of the magnetic nanorod filler

Our paper appeared in ACS Applied Materials & Interfaces.

Saint-Venant's principle and its relatives - part 1

This venerable principle (published in 1855) and a whole family of analogous results can be explained in a very simple, almost geometrical, manner based on the observation that "the Laplacian is a zero-sum game". Within this class of results (with applications ranging from optical microscopes to the metallic mesh on the door of microwave ovens). Saint-Venant's principle is probably the only one to have an official name, but not the easiest to understand, so we will begin by a simple example from electrostatics.

No more access to the APS journals in France

Many (most ?) universities and research institutes in France get access to scientific journals through the Couperin consortium. This year, the consortium failed to reach an agreement¹ with the American Physical Society (publisher of the Physical Review) who increased their 2014 prices by 7.6% with respect to 2013². As a result, our subscription to the Physical Review will stop as of January 1st 2014.

UPDATE 09/01/2014: For the moment, we do have access to the 2014 papers. Couperin will pursue the negotiations until the end of February.

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<sup>1. Letter from the APS to the Couperin consortium. ↩
2. Letter from the APS to French researchers. The 7.6% is the overall price increase requested from the consortium. For the Paris-Sud University, for instance, the increase would be 28%. ↩</sup>

Power-law distribution of war magnitudes

While reading Steven Pinker's The better angels of our nature I stumbled upon the following argument for the magnitude of war (number of casualties) following a power-law distribution (page 220):

Recall the mathematical law that a variable will fall into a power-law distribution if it is an exponential function of a second variable that is distributed exponentially. My own guess is that the combination of escalation and attrition is the best explanation for the power-law distribution of war magnitudes.