Pseudo-distances on symplectomorphism groups and applications to flux theory

Starting from a given norm on the vector space of exact 1-forms of a compact symplectic manifold, we produce pseudo-distances on its symplectomorphism group by generalizing an idea due to Banyaga. We prove that in some cases (which include Banyaga's construction), their restriction to the Hamiltonian diffeomorphism group is equivalent to the distance induced by the initial norm on exact 1-forms. We also define genuine "distances to the Hamiltonian diffeomorphism group" which we use to derive several consequences, mainly in terms of flux groups.Comment: 21 pages, no figure; v2. various typos corrected, some references added. Published in Mathematische Zeitschrif

The Ursinus Weekly, February 3, 1919

Practice teaching and the small college • Gettysburg quintette too speedy for Ursinus • Opening session of the H.-P. group • Ursinus trounces Washington • Brotherhood of St. Paul holds meeting • Campus democracy • Junior girls sell sandwiches for 1920 Ruby • Letter from Guy A. Koons • Ex-business manager of Weekly returns • Schumann quintet coming!https://digitalcommons.ursinus.edu/weekly/2512/thumbnail.jp

Mapping the coevolution of urban energy systems: pathways of change

Abstract. The interface of a long-standing movement for sustainability at the urban scale and the imperatives of the carbon-reduction agenda are driving change in urban energy systems. This paper seeks to address the nature of that change and, in particular, to consider how different pathways of change are emerging. To do this it draws on the coevolution and pathways literatures to interrogate a database of current urban energy initiatives within the UK. This analysis reveals the multiple pathways of change though which new modes of energy production and consumption are being developed to deliver carbon reductions through the reconfiguring of urban energy systems. The paper concludes with a discussion of the implications of these changes for urban governance and for carbon reductions

Energy Loss of Leading Hadrons and Direct Photon production in Evolving Quark-Gluon Plasma

We calculate the nuclear modification factor of neutral pions and the photon yield at high p_T in central Au-Au collisions at RHIC (\sqrt{s}=200 GeV) and Pb-Pb collisions at the LHC (\sqrt{s}=5500 GeV). A leading-order accurate treatment of jet energy loss in the medium has been convolved with a physical description of the initial spatial distribution of jets and a (1+1) dimensional expansion. We reproduce the nuclear modification factor of pion R_{AA} at RHIC, assuming an initial temperature T_i=370 MeV and a formation time \tau_i=0.26 fm/c, corresponding to dN/dy=1260. The resulting suppression depends on the particle rapidity density dN/dy but weakly on the initial temperature. The jet energy loss treatment is also included in the calculation of high p_T photons. Photons coming from primordial hard N-N scattering are the dominant contribution at RHIC for p_T > 5 GeV, while at the LHC, the range 8<p_T<14 GeV is dominated by jet-photon conversion in the plasma.Comment: 21 pages, 16 figures. Discussions and references added. New figure includind photon dat