3,062 research outputs found
On the economic impact of international sport events: microevidence from survey data at the EURO 2008
Using firm-level data for more than 700 Swiss hotels and restaurants, we evaluate the economic impact of the EURO 2008 soccer championship in Switzerland. Although aggregated macrodata do not reveal any sizable economic impact, we report an overall negative effect based on the surveyed companies. Notably the reported effects of the individual firms are very heterogeneous. For instance, hotels in cities benefitted from the tournament as they were able to raise prices and thereby increase sales. Looking at the long-run impact only a small fraction of companies do believe in a positive effect. Interestingly, this outlook does not depend on realized sales, but on the guest structure. © 2014 © 2014 Taylor & Francis
Image resonance in the many-body density of states at a metal surface
The electronic properties of a semi-infinite metal surface without a bulk gap are studied by a formalism that is able to account for the continuous spectrum of the system. The density of states at the surface is calculated within the GW approximation of many-body perturbation theory. We demonstrate the presence of an unoccupied surface resonance peaked at the position of the first image state. The resonance encompasses the whole Rydberg series of image states and cannot be resolved into individual peaks. Its origin is the shift in spectral weight when many-body correlation effects are taken into account
Proximity effecs and curie temperature enhancement in Co/EuS and Fe/EuS multilayers
Two identical Co/EuS and Fe/EuS multilayers of six periods each and with
individual layers of about 4 nm thick are grown by e-beam evaporation under
ultrahigh vacuum conditions. The films show polycrystalline structure with a
grain size limited by the individual layer thickness. Both multilayers consist
of almost continuous layers with some roughness. The surface peak-to-peak
roughness is about 4–5 nm. Magnetization measurements and calculations of the
loops based on a Stoner–Wohlfarth-like model allow us to determine the direct
antiferromagnetic exchange coupling constant between the 3d metal and EuS at 5
K. Both samples show strong enhancement of the Curie temperature of EuS up to
at least 50 K with a EuS magnetization tail, which persists up to about 100 K.
The J = 7/2 character of the EuS layers is shown to be responsible for the
large Curie temperature enhancement
Multisystem proteinopathy due to a homozygous p.Arg159His VCP mutation : a tale of the unexpected
ObjectiveTo assess the clinical, radiologic, myopathologic, and proteomic findings in a patient manifesting a multisystem proteinopathy due to a homozygous valosin-containing protein gene (VCP) mutation previously reported to be pathogenic in the heterozygous state.MethodsWe studied a 36-year-old male index patient and his father, both presenting with progressive limb-girdle weakness. Muscle involvement was assessed by MRI and muscle biopsies. We performed whole-exome sequencing and Sanger sequencing for segregation analysis of the identified p.Arg159His VCP mutation. To dissect biological disease signatures, we applied state-of-the-art quantitative proteomics on muscle tissue of the index case, his father, 3 additional patients with VCP-related myopathy, and 3 control individuals.ResultsThe index patient, homozygous for the known p.Arg159His mutation in VCP, manifested a typical VCP-related myopathy phenotype, although with a markedly high creatine kinase value and a relatively early disease onset, and Paget disease of bone. The father exhibited a myopathy phenotype and discrete parkinsonism, and multiple deceased family members on the maternal side of the pedigree displayed a dementia, parkinsonism, or myopathy phenotype. Bioinformatic analysis of quantitative proteomic data revealed the degenerative nature of the disease, with evidence suggesting selective failure of muscle regeneration and stress granule dyshomeostasis.ConclusionWe report a patient showing a multisystem proteinopathy due to a homozygous VCP mutation. The patient manifests a severe phenotype, yet fundamental disease characteristics are preserved. Proteomic findings provide further insights into VCP-related pathomechanisms
Spin-orbit splitting of image states
We quantify the effect of the spin-orbit interaction on the Rydberg-like
series of image state electrons at the (111) and (001) surface of Ir, Pt and
Au. Using relativistic multiple-scattering methods we find Rashba-like
dispersions with Delta E(K)=gamma K with values of gamma for n=1 states in the
range 38-88 meV Angstrom. Extending the phase-accumulation model to include
spin-orbit scattering we find that the splittings vary like 1/(n+a)^3 where a
is the quantum defect and that they are related to the probability of spin-flip
scattering at the surface. The splittings should be observable experimentally
being larger in magnitude than some exchange-splittings that have been resolved
by inverse photoemission, and are comparable to linewidths from inelastic
lifetimes.Comment: 10 pages, 4 figure
Direct evidence for significant spin-polarization of EuS in Co/EuS multilayers at room temperature
The new era of spintronics promises the development of nanodevices, where the
electron spin will be used to store information and charge currents will be
replaced by spin currents. For this, ferromagnetic semiconductors at room
temperature are needed. We report on significant room-temperature spin
polarization of EuS in Co/EuS multilayers recorded by x-ray magnetic circular
dichroism (XMCD). The films were found to contain a mixture of divalent and
trivalent europium, but only Eu11 is responsible for the ferromagnetic
behavior of EuS. The magnetic XMCD signal of Eu at room temperature could
unambiguously be assigned to magnetic ordering of EuS and was found to be only
one order of magnitude smaller than that at 2.5 K. The room temperature
magnetic moment of EuS is as large as the one of bulk ferromagnetic Ni. Our
findings pave the path for fabrication of room–temperature spintronic devices
using spin polarized EuS layers
Lifetimes of image-potential states on copper surfaces
The lifetime of image states, which represent a key quantity to probe the
coupling of surface electronic states with the solid substrate, have been
recently determined for quantum numbers on Cu(100) by using
time-resolved two-photon photoemission in combination with the coherent
excitation of several states (U. H\"ofer et al, Science 277, 1480 (1997)). We
here report theoretical investigations of the lifetime of image states on
copper surfaces. We evaluate the lifetimes from the knowledge of the
self-energy of the excited quasiparticle, which we compute within the GW
approximation of many-body theory. Single-particle wave functions are obtained
by solving the Schr\"odinger equation with a realistic one-dimensional model
potential, and the screened interaction is evaluated in the random-phase
approximation (RPA). Our results are in good agreement with the experimentally
determined decay times.Comment: 4 pages, 1 figure, to appear in Phys. Rev. Let
Symmetry Analysis of Second Harmonic Generation at Surfaces of Antiferromagnets
Using group theory we classify the nonlinear magneto-optical response at
low-index surfaces of fcc antiferromagnets, such as NiO. Structures consisting
of one atomic layer are discussed in detail. We find that optical second
harmonic generation is sensitive to surface antiferromagnetism in many cases.
We discuss the influence of a second type of magnetic atoms, and also of a
possible oxygen sublattice distortion on the output signal. Finally, our
symmetry analysis yields the possibility of antiferromagnetic surface domain
imaging even in the presence of magnetic unit-cell doubling.Comment: 23 pages, 10 figures incorporated. Accepted to Phys. Rev. B,
scheduled for July'9
Nonlinear Magneto-Optics of Fe Monolayers from first principles: Structural dependence and spin-orbit coupling strength
We calculate the nonlinear magneto-optical response of free-standing fcc
(001), (110) and (111) oriented Fe monolayers. The bandstructures are
determined from first principles using a full-potential LAPW method with the
additional implementation of spin-orbit coupling. The variation of the
spin-orbit coupling strength and the nonlinear magneto-optical spectra upon
layer orientation are investigated. We find characteristic differences which
indicate an enhanced sensitivity of nonlinear magneto-optics to surface
orientation and variation of the in-plane lattice constants. In particular the
crossover from onedimensional stripe structures to twodimensional films of
(111) layers exhibits a clean signature in the nonlinear Kerr-spectra and
demonstrates the versatility of nonlinear magneto-optics as a tool for in situ
thin-film analysis.Comment: 28 pages, RevTeX, psfig, submitted to PR
Self-energy of image states on copper surfaces
We report extensive calculations of the imaginary part of the electron
self-energy in the vicinity of the (100) and (111) surfaces of Cu. The
quasiparticle self-energy is computed by going beyond a free-electron
description of the metal surface, either within the GW approximation of
many-body theory or with inclusion, within the GW approximation, of
short-range exchange-correlation effects. Calculations of the decay rate of the
first three image states on Cu(100) and the first image state on Cu(111) are
also reported, and the impact of both band structure and many-body effects on
the electron relaxation process is discussed.Comment: 8 pages, 5 figures, to appear in Phys. Rev.
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