7 January 2017

Liberalism vs. Conservatism

I have always found the liberal/conservative distinction difficult to draw, largely due to the several meanings of each term (e.g. the concept of "liberal" in political science and its casual use in the United States, on the one hand, and in Europe on the other.) Motivated by my recent reading of David Gress' From Plato to Nato, I tried to define each side by a set of principles, as small and as general as possible. This is my first attempt (work very much in progress):

Liberal

(L1) Individuals are equal.
(L2) The individual precedes the community (ontologically).

Conservative

(C1) The community takes precedence over the individual.
(C2) The "essence" of the community defines a set of values (religious, national etc.) that limits individual freedom.

Below the fold I discuss some consequences of these definitions.

4 January 2017

From Plato to NATO - review

      I have spent some time reading through David Gress' From Plato to Nato. I was not very impressed by the book, but the exercise helped me reflect on the definition of liberalism and on the difference with respect to conservatism, so I took the opportunity to write a reaction (more than a review).

      Gress presents his whole interpretation as opposed to a "Grand Narrative" (GN) that has supposedly been very popular and that hides the true origins of Western civilization. His Introduction starts by:

      Liberty grew because it served the interests of power. [...] The key historical insight underlying this book is that liberty, and Western identity in general, are not primarily to be understood in the abstract, but as a set of practices and institutions that evolved, not from Greece, but from the synthesis of classical, Christian, and Germanic culture that took shape from the fifth to the eighth centuries A.D.

      This phrase summarizes not only the author's conclusions, but also his strategy of discourse: he switches before the history of ideas and that of events, favoring the latter but also resorting to the former when needed.

      18 December 2016

      Business as usual at the White House

      After the generalized commotion surrounding the US elections died down, the feeling of surprise lingered in the press, combined with predictions of imminent disaster. Against this alarmist tendency, I'm putting forward three obvious points:
      1. Although Trump's victory was unexpected (i.e. went against poll predictions), it follows a long-term pattern of Republican and Democratic presidents alternating every eight years. This has been the case since Eisenhower, with the exception of Reagan's first mandate.
      2. Speaking of Reagan, there are some striking similarities with Trump: both are (were) charismatic showmen, but not very intellectual and with a penchant for made-up stories. Time will tell how deep this resemblance goes.
      3. In contrast with his populist campaign speeches, Trump's post-election declarations and his cabinet choices signal that he will probably follow very closely the Republican platform: pro-big business, anti-abortion, pro-Israel, anti-environment control, for increased military spending, tax cuts for the rich, free trade and reductions in welfare programs. How many of these points were also on Clinton's agenda is left as an exercise for the reader.
      Finally, what alarms me is not how far Trump is from mainstream Republicans, but rather how close the Republican party is to Trump.

      1 December 2016

      CNRS positions - the 2017 campaign

      The detail of the 2017 campaign for permanent research positions at the CNRS (Centre national de la recherche scientifique) has been published in the Journal Officiel (see links below) and the submission site is open. The submission deadline is January 6th 2017. There are 211 open positions at the CR2 level (4 less than in 2016), 75 CR1 (2 less), 256 DR2 (+3) and 2 DR1 (+2). The total number has been stable over the last five years, as shown in the graph below:

      The official texts: CR2, CR1, DR2, DR1.

      20 November 2016

      The Ewald sphere

      The Ewald sphere is a widely used concept, but one that is quite difficult to grasp in the beginning (at least it was for me, as well as for some of my colleagues.) It can be seen as a way of converting vectors between the "real" space, in which the experiment is performed, and "reciprocal" space.

      18 November 2016

      Solution Self-Assembly of Plasmonic Janus Nanoparticles

      Our paper appeared in Soft Matter.


      Congratulations to Nicolò Castro for his first paper as first author!

      21 October 2016

      10 October 2016

      Curvature of a planar curve

      I have done this calculation several times over the years, so I might as well write it down in detail, in case it may be of use to someone else.


      We are interested in the curvature \(C = 1/R\) of a planar curve \(y=f(x)\) at a given point A, where \(R\) is the curvature radius at that particular point, defined with respect to the curvature center \(O\) (intersection of the normals raised to the curve in A and its infinitesimal neighbor B.)

      The angle subtending AB is: \(\displaystyle \mathrm{d}\alpha = \mathrm{d}s/R \Rightarrow C = \frac{\mathrm{d}\alpha}{\mathrm{d}s}\)
      The length of the curve element AB is: \(\displaystyle \mathrm{d}s = \sqrt{\mathrm{d}x^2 + \mathrm{d}y^2} \Rightarrow \frac{\mathrm{d}s}{\mathrm{d}x } = \sqrt{1+ f'(x)^2}\)

      The derivative of \(f\) is directly related to the angle \(\alpha\): \(\displaystyle f'(x) = \frac{\mathrm{d}y}{\mathrm{d}x} = \tan \alpha \Rightarrow \alpha = \arctan \frac{\mathrm{d}y}{\mathrm{d}x} = \arctan [f'(x)] \Rightarrow \frac{\mathrm{d}\alpha}{\mathrm{d}x} = \frac{1}{1+f'(x)^2} f''(x)\)

      Putting together the three relations above yields:
      \[C = \frac{\mathrm{d}\alpha}{\mathrm{d}s} = \frac{f''(x)}{\left [ 1 + f'(x)^2\right ]^{3/2}}\]