7,489 research outputs found
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
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