December 22, 2020

CNRS positions - the 2021 campaign

The 2021 campaign for permanent research positions at the CNRS (Centre national de la recherche scientifique) is open (see the submission site). The deadline is January 7th 2021 (13:00 Paris time). There are 242 open positions at the CR level and 261 for DR2: these numbers have been almost constant since 2019, as shown in the graph below:

The official texts: CRCN, DR2.
 
 The results of the 2020 campaign are no longer available on the CNRS site, but they have been aggregated by François-Xavier Coudert here. It might be interesting to note a large number of changes (marked by red background) between the admissibility and the admission phases.
 

July 19, 2020

Sites web inofficiels des différentes sections du CoNRS

[Mise à jour 02/10/2020:  Une liste plus complète est disponible ici]

[Liste mise à jour 19/07/2020]
La date limite de soumission des dossiers de candidature aux concours CNRS est le 7 janvier. Tous les candidats connaissent sûrement le site officiel de l'institution. On sait peut-être moins bien que les différentes sections du Comité National (CoNRS), responsables de la sélection des candidats (phase d'admissibilité) ont souvent des sites inofficiels, contenant des renseignements supplémentaires.
 
Voici une liste (probablement incomplète) de tels sites. N'hésitez pas à me transmettre l'adresse d'autres sites ne figurant pas ci-dessous !

Section 05  (obsolète)
Section 08  (obsolète)
Section 09  (2012-2016)
Section 18  (2008-2012)
Section 34  (2012-2016)
Section 41 (ancienne 01 ! Mathématiques)
Section 50 (interdisciplinaire)

March 24, 2020

Real-Time In Situ Observations Reveal a Double Role for Ascorbic Acid in the Anisotropic Growth of Silver on Gold

Our paper has just been published in J. Phys. Chem. Letters!
The preprint is available here

What we have found is that ascorbic acid, widely used as a mild reducing agent, also plays a shape-directing role. These two actions are difficult to decouple, since a reductant is always needed to perform reduction reactions. The workaround we found was employing the reactive species generated by the electron beam in the observation cell. 

The result is well captured by the following movies, recorded with and without ascorbic acid (all other things being equal.)

With ascorbic acid 

Without ascorbic acid

February 22, 2020

Hempel's paradox

A quick note on Hempel's paradox (if this is what it is):
  • If I open my wardrobe and see a white shoe, this is not much of a confirmation of the sentence p = "All ravens are black".
  • If, however, I see in the middle of a bunch of ravens a white object that looks bird-shaped and, after further inspection, it turns out to be a shoe (rather than a raven), then there is substantial confirmation (or lack of infirmation?) of p, probably much stronger than simply observing another black raven nearby. [Is it correct to split the observation into the two steps and take the first as some sort of "prior" for the second?]
I'm trying to find realistic circumstances (less contrived than Good's "red herring" example, anyway) where an instance of the contrapositive of p yields more evidence for p than simply an instance of p.