New compact forms of the trigonometric Ruijsenaars-Schneider system

The reduction of the quasi-Hamiltonian double of ${\mathrm{SU}}(n)$ that has been shown to underlie Ruijsenaars' compactified trigonometric $n$-body system is studied in its natural generality. The constraints contain a parameter $y$, restricted in previous works to $0<y < \pi/n$ because Ruijsenaars' original compactification relies on an equivalent condition. It is found that allowing generic $0<y<\pi/2$ results in the appearance of new self-dual compact forms, of two qualitatively different types depending on the value of $y$. The type (i) cases are similar to the standard case in that the reduced phase space comes equipped with globally smooth action and position variables, and turns out to be symplectomorphic to ${\mathbb{C}P^{n-1}}$ as a Hamiltonian toric manifold. In the type (ii) cases both the position variables and the action variables develop singularities on a nowhere dense subset. A full classification is derived for the parameter $y$ according to the type (i) versus type (ii) dichotomy. The simplest new type (i) systems, for which $\pi/n < y < \pi/(n-1)$, are described in some detail as an illustration.Comment: 31 page

Verliebt – Verlobt – Verheiratet:Wandel der Hochzeit im 20. Jahrhundert

Die Entscheidung zu heiraten gilt heute als höchstpersönliche Angelegenheit des Brautpaares und Grundstein ihres individuellen Glücks. Doch wenn ein Paar heiratet, ist das nicht nur eine private Entscheidung. Die Brautleute sind immer auch Einflüssen aus Elternhaus, Kirche, Gesamtgesellschaft und Staat ausgesetzt und wirken ihrerseits mit ihrer Entscheidung auf diese Institutionen zurück. Änderungen im Heiratsverhalten stellen somit einen wichtigen Indikator für gesellschaftliche Entwicklungen dar. Um diese Entwicklungen erfassen und darstellen zu können, hat eine Gruppe von acht Teilnehmerinnen und Teilnehmern des Studiums im Alter an der Universität Münster, die Geschichte der Hochzeit im 20. Jahrhundert im Vergleich der Hochzeitsgenerationen der Studierenden (Heirat 1960-75), ihrer Eltern (Heirat 1930-45) und Großeltern (Heirat 1900-1915) untersucht. Hierzu recherchierte die Gruppe in Archiven und Bibliotheken und wertete 586 für das Projekt entwickelte, standardisierte Fragebögen aus

Exploring CEvNS with NUCLEUS at the Chooz Nuclear Power Plant

Coherent elastic neutrino-nucleus scattering (CE$\nu$NS) offers a unique way to study neutrino properties and to search for new physics beyond the Standard Model. Nuclear reactors are promising sources to explore this process at low energies since they deliver large fluxes of (anti-)neutrinos with typical energies of a few MeV. In this paper, a new-generation experiment to study CE$\nu$NS is described. The NUCLEUS experiment will use cryogenic detectors which feature an unprecedentedly low energy threshold and a time response fast enough to be operated in above-ground conditions. Both sensitivity to low-energy nuclear recoils and a high event rate tolerance are stringent requirements to measure CE$\nu$NS of reactor antineutrinos. A new experimental site, denoted the Very-Near-Site (VNS) at the Chooz nuclear power plant in France is described. The VNS is located between the two 4.25 GW$_{\mathrm{th}}$ reactor cores and matches the requirements of NUCLEUS. First results of on-site measurements of neutron and muon backgrounds, the expected dominant background contributions, are given. In this paper a preliminary experimental setup with dedicated active and passive background reduction techniques is presented. Furthermore, the feasibility to operate the NUCLEUS detectors in coincidence with an active muon-veto at shallow overburden is studied. The paper concludes with a sensitivity study pointing out the promising physics potential of NUCLEUS at the Chooz nuclear power plant

Intégration des inondations et du potentiel des contraintes thermiques à Tainan (Taiwan) et Groningen (Pays-Bas)

Stormwater flooding and thermal stresses of citizens are two important phenomena for most of the dense urban area. Due to the climate change, these two phenomena will occur more frequently and cause serious problems. Therefore, the sectors for public health and disaster management should be able to assess the vulnerability to stormwater flooding and thermal stress. To achieve this goal, two cities in different climate regions and with different urban context have been selected as the pilot areas, i.e., Tainan, Taiwan and Groningen, Netherlands. Stormwater flooding and thermal stress maps will be produced for both cities for further comparison. The flooding map indicates vulnerable low lying areas, where the thermal stress map indicates high Physiological Equivalent Temperature (PET) values (thermal comfort) in open areas without shading. The combined map indicates the problem areas of flooding and thermal stress and can be used by urban planners and other stakeholders to improve the living environment. -- Les inondations consécutives à des pluies torrentielles, ainsi que le stress thermique dû à des canicules, sont deux phénomènes inquiétants pour la plupart des centres urbains, densément peuplés. Par suite du changement climatique, ces deux phénomènes se produiront à l’avenir plus souvent, et peuvent conduire à de graves problèmes. C’est pourquoi les départements de la santé publique et de la gestion des catastrophes naturelles voudraient être en mesure d’évaluer la vulnérabilité de leurs centres urbains face à des situations d’inondations et de stress thermique. Pour atteindre cet objectif, un projet de recherche a été lancé, en se basant sur deux villes différentes quant à leur région climatique et leur contexte urbain: Tainan à Taïwan et Groningen aux Pays-Bas. Le projet permettra d’élaborer des cartes indiquant les risques dans les deux cas, afin de permettre des comparaisons ultérieures. Une carte d’altitude indiquera les zones basses, vulnérables à des inondations, et une carte thermique montrera où sont les températures physiologiques équivalentes (valeurs PET) élevées. La carte combinée permettra d’identifier les zones à problèmes d’inondation et de stress thermique, et pourra être utilisées par les urbanistes et les autres parties prenantes pour améliorer notre environnement