Absence of a local rest frame in far from equilibrium quantum matter

In a collision of strongly coupled quantum matter we find that the dynamics of the collision produces regions where a local rest frame cannot be defined because the energy-momentum tensor does not have a real time-like eigenvector. This effect is purely quantum mechanical, since for classical systems, a local rest frame can always be defined. We study the relation with the null and weak energy condition, which are violated in even larger regions, and compare with previously known examples. While no pathologies or instabilities arise, it is interesting that regions without a rest frame are possibly present in heavy ion collisions.Comment: 5 pages, 4 figures; v2: fixed typo, v3: added references, matches published versio

International framework agreements: new paths to workers' participation in multinationals'governance?

This article describes the results of a major study on the impact of codes of conduct and international framework agreements (IFAs) on social regulation at company level. The limits of labour legislation at the national, as well as the international, level provide a strong motivation for both multinationals and trade unions to negotiate and sign IFAs. IFAs offer a way to regulate the social consequences of globalisation and to secure adherence to labour and social standards. They thus form part of the growing political debate on the international working and production standards of private actors. Examination of the negotiation process, the motivations of the parties, and the content of the agreements and implementation measures provides valuable insights into the impact of IFAs on multinationals' behaviour in respect of social dialogue and core labour standards. Finally, the article highlights the influence of such agreements on public policy-making and the limits of private self-regulation at European and international level, addressing the growing and controversial debate on the need for supranational structures to regulate labour standards and industrial relations.Cet article décrit les résultats d'une étude majeure sur l'impact des codes de conduite et des accords cadres internationaux (ACI) sur la réglementation sociale au niveau de l'entreprise. Les limites de la législation du travail aux niveaux tant national qu'international motivent fortement et les multinationales et les syndicats à négocier et à signer des ACI. Les ACI offrent un moyen de réguler les conséquences sociales de la globalisation et de garantir une adhésion aux normes sociales et aux normes du travail. Ils font donc partie du débat politique croissant sur les normes du travail et de production internationales des acteurs privés. L'examen du processus de négociation, des motivations des parties, du contenu des accords et des mesures de mise en oeuvre permet de se forger une idée claire et utile de l'impact des ACI sur le comportement des multinationales en matière de respect du dialogue social et des normes du travail fondamentales. Enfin, l'article met en évidence l'influence de tels accords sur les politiques adoptées par les autorités publiques et les limites de l'autorégulation privée aux niveaux européen et international, en abordant le débat croissant et controversé sur le besoin de structures supranationales pour réguler les normes du travail et les relations professionnelles

Comment on "Antilocalization in a 2D Electron Gas in a Random Magnetic Field"

In a recent Letter, Taras-Semchuk and Efetov reconsider the problem of electron localization in a random magnetic field in two dimensions. They claim that due to the long-range nature of the vector potential correlations an additional term appears in the effective field theory ($\sigma$-model) of the problem, leading to delocalization at the one-loop level. This calls into question the results of earlier analytical studies, where the random magnetic field problem was mapped onto the conventional unitary-class $\sigma$-model, implying that the leading quantum correction is of two-loop order and of a localizing nature. We show in this Comment, however, that the new term in fact does not exist and was erroneously obtained by Taras-Semchuk and Efetov because of an inconsistent treatment violating gauge invariance.Comment: 1 page, 2 figure

Verdrängte Beruflichkeit - Renaissance des Berufsprinzips?

"Die jüngsten Erfolge von Berufsgewerkschaften sind eine Tatsache. Der Essay geht der Frage nach, ob man es hier nicht mit einem dreifachen Phänomen der 'verdrängten Beruflichkeit' in der gewerkschaftlichen Organisationsgeschichte, ihrer Historiographie und der korrespondierenden Industriesoziologie zu tun hat. Der Beitrag plädiert dafür, der Bedeutung von Beruflichkeit und Berufsprinzip als Medium der Bindung der Mitglieder an die Organisation wieder größere Aufmerksamkeit zu widmen und unter diesem Aspekt die aktuellen Erfolge von Berufsgewerkschaften nicht nur zu kritisieren oder abzulehnen, sondern ernst zu nehmen." (Autorenreferat)"The recent successes of professional unions are undeniable. This essay poses the question whether there is a triple phenomenon of 'excluded professionalism' within (German) union history, its historiography and corresponding industrial sociology. The article argues there is a need for greater attention to professions and professionalism as principles binding Union members to representative organizations, and therefore to learn from the current success of these unions instead of criticizing or even rejecting them." (author's abstract

Von nichts zu viel: Suffizienz gehört zur Zukunftsfähigkeit. Über ein Arbeitsvorhaben des Wuppertal Instituts

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Periodic solutions and refractory periods in the soliton theory for nerves and the locust femoral nerve

Close to melting transitions it is possible to propagate solitary electromechanical pulses which reflect many of the experimental features of the nerve pulse including mechanical dislocations and reversible heat production. Here we show that one also obtains the possibility of periodic pulse generation when the boundary condition for the nerve is the conservation of the overall length of the nerve. This condition generates an undershoot beneath the baseline (`hyperpolarization') and a `refractory period', i.e., a minimum distance between pulses. In this paper, we outline the theory for periodic solutions to the wave equation and compare these results to action potentials from the femoral nerve of the locust (locusta migratoria). In particular, we describe the frequently occurring minimum-distance doublet pulses seen in these neurons and compare them to the periodic pulse solutions.Comment: 10 pages, 6 Figure