Body Consciousness in Modern Urban Surroundings: Freerunning and Parkour

The paper covers the matter of body consciousness in modern urban surroundings. Somatic disciplines known as Freerunning and Parkour are presented as activities of a performative nature that can be understood and practised as means of redefining an aesthetic experience in modern urban surroundings

Strongly magnetized rotating dipole in general relativity

Electromagnetic waves arise in many area of physics. Solutions are difficult to find in the general case. In this paper, we numerically integrate Maxwell equations in a 3D spherical polar coordinate system. Straightforward finite difference methods would lead to a coordinate singularity along the polar axis. Spectral methods are better suited to deal with such artificial singularities related to the choice of a coordinate system. When the radiating object is rotating like for instance a star, special classes of solutions to Maxwell equations are worthwhile to study such as quasi-stationary regimes. Moreover, in high-energy astrophysics, strong gravitational and magnetic fields are present especially around rotating neutron stars. In order to study such systems, we designed an algorithm to solve the time-dependent Maxwell equations in spherical polar coordinates including general relativity as well as quantum electrodynamical corrections to leading order. As a diagnostic, we compute the spindown luminosity expected from these stars and compare it to the classical i.e. non relativistic and non quantum mechanical results. It is shown that quantum electrodynamics leads to an irrelevant change in the spindown luminosity even for magnetic field around the critical value of \numprint{4.4e9}~\si{\tesla}. Therefore the braking index remains close to its value for a point dipole in vacuum namely $n=3$. The same conclusion holds for a general-relativistic quantum electrodynamically corrected force-free magnetosphere.Comment: Accepted for publication in A&

Anomalous decays of pseudoscalar mesons

In this thesis we discuss the decays of the pseudoscalar mesons (the neutral pion, the eta and eta-prime) which are governed by the chiral anomaly. Some of these decays are of special interest because their study permits a deep insight into aspects of modern physics. The decays can be classified according to the type of the anomaly (triangle or box) that governs the corresponding amplitude when it is extrapolated to the chiral point. In order to take the momentum dependencies of the form factors into account, the actual calculations are performed in the frame work of vector meson dominance (VMD) models, namely in terms of the original hidden gauge model and modern generalized models. The results of the triangle-anomaly sector show that the hidden gauge model and the modern modifications can describe the data equally well. In the box-anomaly sector the data have a slight preference to the modern modified VMD formulation. The results of the latter also agree very well with the predictions of unitarized chiral perturbation theory. In the case of the box-anomaly decays, we especially analyze the contributions of an unconventional untested CP-violating electric dipole form factor that is sensitive to the strange-quark/antiquark-content of the eta and eta-prime mesons. We verify the claim that it could still be of natural size by comparing with the new KLOE data for eta-> pi+ pi- e+ e-.Comment: 101+6 pages,42 figures, Diplom-Thesis, University of Bonn, July 201

Critical fluctuations in the breakdown of disordered systems

In this paper some critical aspects of the behaviour of breaking lattices subject to slow driving forces are briefly reviewed. In particular fluctuations in the response to the variation of external parameters are discussed.Comment: Presented at the workshop honoring Antonio Coniglio's 60th birthda

The public domain vs. the museum: the limits of copyright and reproductions of two-dimensional works of art

The problem of museums and public institutions handling reproductions of works in their collections is not only a legal question but also one of museum ethics. Public museums are committed to spreading knowledge and to making their collections accessible. When it comes to images of their holdings, however, they often follow a restrictive policy. Even for works in the public domain they claim copyright for their reproductive photographs. This paper offers an analysis of the different interests at stake, a short survey of important cases, and practical recommendations