CFT in Conformally Flat Spacetimes

A new class of conformal field theories is presented, where the background gravitational field is conformally flat. Conformally flat (CF) spacetimes enjoy conformal properties quite similar to the ones of flat spacetime. The conformal isometry group is of maximal rank and the conformal Killing vectors in conformally flat coordinates are {\em exactly} the same as the ones of flat spacetime. In this work, a new concept of distance is introduced, the {\em conformal distance}, which transforms covariantly under all conformal isometries of the CF space. It is shown that precisely for CF spacetimes, an adequate power of the said conformal distance is a solution of the non-minimal d'Alembert equation.Comment: Minor changes and some clarifications added. Published version. 16 page

Measuring the impact of on the job training on job mobility

This paper studies the effect of employer-provided training on the probability of subsequent job exit. Empirical evidence usually shows that the probability of receiving training by the employer is higher among those employees with the lowest expected rates of turnover. Therefore, it seems that firms provide training selectively. In this paper, we address the empirical question of to what extent this endogeneity problem leads to a spurious correlation between training receipt and job mobility. Using Spanish Data from the European Community Household Panel, we provide estimates that ignore the selection bias and compare the results with the ones obtained when correcting for the possible nonrandom selection between trainees and non-trainees. Overall, our results show that there is a negative correlation between on the job training and job mobility, but only for fired workers, and not for voluntary movers. Nonetheless, once the endogeneity problem is accounted, the negative effect becomes statistically nonsignificant for all types of movers.Raquel Carrasco acknowledges research funding from the Spanish Ministry of Science and Innovation, Grant No. ECO2012-31358

Décor et dédoublement fantastiques : une Sacrée garce et L'Homme et le serpent d'Ambrose Bierce

Le monstre intérieur est l'une des plus terribles menaces dans le récit fantastique. Il arrive que face à l'irruption de l'impossible, les personnages doivent lutter contre l'inconnu le plus létal qui soit: eux-mêmes. Il est question dans cet article des mécanismes de la peur et des étapes enclenchées par ce fantastique tourné vers le Moi. Le surnaturel a besoin d'une fissure dans laquelle se faufiler. Chez Bierce, c'est la fragilité psychologique -en particulier la culpabilité à forte résonnance chrétienne ou crainte du sacré- qui rend vulnérable et réceptif au surnaturel et à la terreur. Cet état a pour faculté de transformer un décor neutre en un environnement angoissant et menaçant non sans en exploiter son potentiel sinistre, telle une projection extérieure de la faute intérieure torturant les personnages. S'enclenche alors une lutte interne chez ces derniers, établissant un décor psychologique propice à l'irruption du surnaturel renforcé par des références aux superstitions et peurs ancestrales auxquelles n'échappent pas les héros des deux contes. Les personnages succombent à la terreur sacrée ou numen (primitif) de Rudolf Otto, une variante de la terreur cosmique lovecraftienne. Entre alors en jeu la perturbation des sens. La suggestion enveloppe les personnages, augmente leur angoisse et la sensation d'enfermement sur eux-mêmes. Ils perdent pied et prennent à la fois conscience du danger de mort et de leur impuissance qui les condamne à une mort inéluctable. L'enfermement mental culmine par l'enfermement physique au moyen d'une mise en abyme stylistique. Paralysés, les personnages s'engagent dans une lutte interne qui aboutit à l'irruption du double, le seul recours trouvé par leurs esprits perturbés pour affronter l'impossible. Mais ils deviennent « étrangers vis-à-vis d'eux-mêmes » et par conséquent leurs propres bourreaux respectifs. Ce dédoublement déclenche des doutes angoissants sur leur propre identité, laquelle se révèle sous un aspect méconnu jusqu'alors. L'inconnu, le danger, ce sont eux. Ils se retrouvent enfermés «en» et «par» eux-mêmes. Ils sont donc condamnés, car nul ne peut échapper à soi-même

Latin Amerika’da sosyal düşüncenin dekolonizasyonuna doğru: İbn Haldun yöntemleri

Six centuries have passed since the death of the great Andalusian thinker Ibn Khaldun, in his time one of the brightest and most universal minds, who gave us considerable insights in all the fields of social thought. In these times we must look for alternative thought patterns that allow us to explain and achieve proposals that may face the decay of regimes based on the abuse of power, violence, spendthrift and inequality, which threaten to destroy the social foundations of life on earth. This is our concern and in this paper we will try to reconsider some of Ibn Khaldun’s ideas in order to formulate alternatives that are both theoretically sound and socially efficient to rebuild our understanding of the social dynamics, and to contribute to the recovery of the dignity, solidarity, justice and austerity that can make collective life a viable foundation for the world that will arise from the present crisis.Ölümünün üzerinden 6 yüz yıl geçen, zamanının en parlak ve evrensel düşünürü olan Endülüslü düşünür İbn Haldun bize sosyal düşüncenin tüm alanlarında çok derin bakış açıları sunmuştur. Günümüzde sosyal yaşantının temellerini sarsan, iktidarlar tarafından gücün istismarı, şiddet, israf, adaletsizlik gibi konulara alternatife bakış açıları getirecek yaklaşımlara ihtiyacımız vardır. Bu yazının amcacıda teorik olarak güçlü ve sosyal olarak etkili olabilecek sosyal dinamikleri yeniden yapılandıracak ve onurlu, güçlü, ve adaletli bir birlikteliği geliştirebilecek ve günümüz krizlerine çözüm getirebilecek olan Ibn Haldun’un fikirlerini gözden geçirmektir

Au fil des îles, archipels

L’exposition Au fil des îles, archipels a été présentée au Centre d’exposition de l’Université de Montréal du 8 septembre au 19 novembre 2022 dans le cadre de la programmation 2022-2023

Intercalative DNA binding of the marine anticancer drug variolin B

Variolin B is a rare marine alkaloid that showed promising anti-cancer activity soon after its isolation. It acts as a cyclin-dependent kinase inhibitor, although the precise mechanism through which it exerts the cytotoxic effects is still unknown. The crystal structure of a variolin B bound to a DNA forming a pseudo-Holliday junction shows that this compound can also contribute, through intercalative binding, to either the formation or stabilization of multi-stranded DNA forms.Peer ReviewedPostprint (published version

Weyl anomalies and the nature of the gravitational field

The presence of gravity generalizes the notion of scale invariance to Weyl invariance, namely, invariance under local rescalings of the metric. In this work, we have computed the Weyl anomaly for various classically scale or Weyl invariant theories, making particular emphasis on the differences that arise when gravity is taken as a dynamical fluctuation instead of as a non-dynamical background field. We find that the value of the anomaly for the Weyl invariant coupling of scalar fields to gravity is sensitive to the dynamical character of the gravitational field, even when computed in constant curvature backgrounds. We also discuss to what extent those effects are potentially observable.Comment: 37 pages, 1 tabl