1,525 research outputs found
BEPS Action 2: 2014 Deliverable Neutralising the Effects of Hybrid Mismatch Arrangements and its compatibility with the non-discrimination provisions in tax treaties and the Treaty on the Functioning of the European Union
This article illustrates the BEPS proposals to fight against hybrid mismatch arrangements. It concentrates on exemption / non-inclusion schemes and double deduction schemes and analyses whether these proposals are in line with the non-discrimination provisions contained in tax treaties and in the TFEU. The article comes to the conclusion that the proposals generally comply with the non-discrimination provisions. However, with regard to double deduction schemes the OECD proposes to deny a deduction in the permanent establishment state if the payments are also deductible in the head office state. In the author's opinion this recommendation conflicts with the freedom of establishment contained in the TFEU
Liver transplantation in primary biliary cirrhosis: Risk assessment and 11-year follow-up
Background/Aims: Liver transplantation (LTx) is the only established treatment in patients with end-stage primary biliary cirrhosis (PBC). Although short-term survival after LTx in this group of patients is usually good, few data exist on the long-term survival. The optimal timing of transplantation is difficult. Thus, the aims of this study were to assess the long-term survival of patients with PBC after LTx and to identify potential predictive factors for a positive outcome. Methods: Survival of 28 patients with PBC who underwent LTx between 1985 and July 1999 in a single center was studied by Kaplan-Meier analysis and was compared to predicted survival without LTx using established prognostic models for PBC, the Mayo and European risk scores. Potential prognostic parameters obtained before LTx were tested for correlation to survival. Rates of bone fractures as markers of hepatic osteodystrophy were compared before and after LTx. Results: Median follow-up after LTx was 90 months with a maximum of 140 months. Actuarial survival of patients with PBC was 89% after 1, 5, and 10 years and was significantly better than estimated survival without LTx after 1-7 years as calculated by the Mayo and European risk scores. Of several parameters tested, only serum bilirubin and the prognostic scores, but no other liver function tests obtained immediately prior to transplantation were significantly correlated with survival after LTx. The duration of intensive care after LTx was not associated with any parameters obtained before LTx. Bone fractures were diagnosed in 43% of patients of whom the vast majority were osteopenic before LTx as determined by osteodensitometry. Conclusion: Longterm survival of a well-defined group of patients with PBC was excellent after LTx and was inversely correlated with preoperative serum bilirubin levels as well as Mayo and European risk scores. Copyright (C) 2000 S. Karger AG. Basel
Kinematics and helicity evolution of a loop-like eruptive prominence
We aim at investigating the morphology, kinematic and helicity evolution of a
loop-like prominence during its eruption. We use multi-instrument observations
from AIA/SDO, EUVI/STEREO and LASCO/SoHO. The kinematic, morphological,
geometrical, and helicity evolution of a loop-like eruptive prominence are
studied in the context of the magnetic flux rope model of solar prominences.
The prominence eruption evolved as a height expanding twisted loop with both
legs anchored in the chromosphere of a plage area. The eruption process
consists of a prominence activation, acceleration, and a phase of constant
velocity. The prominence body was composed of left-hand (counter-clockwise)
twisted threads around the main prominence axis. The twist during the eruption
was estimated at 6pi (3 turns). The prominence reached a maximum height of 526
Mm before contracting to its primary location and partially reformed in the
same place two days after the eruption. This ejection, however, triggered a CME
seen in LASCO C2. The prominence was located in the northern periphery of the
CME magnetic field configuration and, therefore, the background magnetic field
was asymmetric with respect to the filament position. The physical conditions
of the falling plasma blobs were analysed with respect to the prominence
kinematics. The same sign of the prominence body twist and writhe, as well as
the amount of twisting above the critical value of 2pi after the activation
phase indicate that possibly conditions for kink instability were present. No
signature of magnetic reconnection was observed anywhere in the prominence body
and its surroundings. The filament/prominence descent following the eruption
and its partial reformation at the same place two days later suggest a confined
type of eruption. The asymmetric background magnetic field possibly played an
important role in the failed eruption.Comment: 9 pages, 8 figures, in press in A&
Evolution of Anemone AR NOAA 10798 and the Related Geo-Effective Flares and CMEs
We present a detailed examination of the features of the Active Region (AR)
NOAA 10798. This AR generated coronal mass ejections (CMEs) that caused a large
geomagnetic storm on 24 August 2005 with the minimum Dst index of -216 nT. We
examined the evolution of the AR and the features on/near the solar surface and
in the interplanetary space. The AR emerged in the middle of a small coronal
hole, and formed a {\it sea anemone} like configuration. H filaments
were formed in the AR, which have southward axial field. Three M-class flares
were generated, and the first two that occurred on 22 August 2005 were followed
by Halo-type CMEs. The speeds of the CMEs were fast, and recorded about 1200
and 2400 km s, respectively. The second CME was especially fast, and
caught up and interacted with the first (slower) CME during their travelings
toward Earth. These acted synergically to generate an interplanetary
disturbance with strong southward magnetic field of about -50 nT, which was
followed by the large geomagnetic storm.Comment: 32 pages, 9 figures, JGR accepte
Relationship between eruptions of active-region filaments and associated flares and CMEs
To better understand the dynamical process of active-region filament
eruptions and associated flares and CMEs, we carried out a statistical study of
120 events observed by BBSO, TRACE, and t(SOHO/EIT) from 1998 to 2007 and
combined filament observations with the NOAA's flare reports, MDI magnetograms,
and LASCO data, to investigate the relationship between active-region filament
eruptions and other solar activities. We found that 115 out of 120 filament
eruptions are associated with flares. 56 out of 105 filament eruptions are
found to be associated with CMEs except for 15 events without corresponding
LASCO data. We note the limitation of coronagraphs duo to geometry or
sensitivity, leading to many smaller CMEs that are Earth-directed or well out
of the plane of sky not being detected by near-Earth spacecraft. Excluding
those without corresponding LASCO data, the CME association rate of
active-region filament eruptions clearly increases with X-ray flare class from
about 32% for C-class flares to 100% for X-class flares. The eruptions of
active-region filaments associated with Halo CMEs are often accompanied by
large flares. About 92% events associated with X-class flare are associated
with Halo CMEs. Such a result is due to that the Earth-directed CMEs detected
as Halo CMEs are often the larger CMEs and many of the smaller ones are not
detected because of the geometry and low intensity. The average speed of the
associated CMEs of filament eruptions increases with X-ray flare size from
563.7 km/s for C-class flares to 1506.6 km/s for X-class flares. Moreover, the
magnetic emergence and cancellation play an important role in triggering
filament eruptions. These findings may be instructive to not only in respect to
the modeling of active-region filament eruptions but also in predicting flares
and CMEs.Comment: 19 Pages, 7 figures, Accepted for publication in MNRA
Low-Energy Theorems from Holography
In the context of gauge/gravity duality, we verify two types of gauge theory
low-energy theorems, the dilation Ward identities and the decoupling of heavy
flavor. First, we provide an analytic proof of non-trivial dilation Ward
identities for a theory holographically dual to a background with gluon
condensate (the self-dual Liu--Tseytlin background). In this way an important
class of low-energy theorems for correlators of different operators with the
trace of the energy-momentum tensor is established, which so far has been
studied in field theory only. Another low-energy relationship, the so-called
decoupling theorem, is numerically shown to hold universally in three
holographic models involving both the quark and the gluon condensate. We show
this by comparing the ratio of the quark and gluon condensates in three
different examples of gravity backgrounds with non-trivial dilaton flow. As a
by-product of our study, we also obtain gauge field condensate contributions to
meson transport coefficients.Comment: 32 pages, 4 figures, two references added, typos remove
A measurement of the tau mass and the first CPT test with tau leptons
We measure the mass of the tau lepton to be 1775.1+-1.6(stat)+-1.0(syst.) MeV
using tau pairs from Z0 decays. To test CPT invariance we compare the masses of
the positively and negatively charged tau leptons. The relative mass difference
is found to be smaller than 3.0 10^-3 at the 90% confidence level.Comment: 10 pages, 4 figures, Submitted to Phys. Letts.
WW Production Cross Section and W Branching Fractions in e+e- Collisions at 189 GeV
From a data sample of 183 pb^-1 recorded at a center-of-mass energy of roots
= 189 GeV with the OPAL detector at LEP, 3068 W-pair candidate events are
selected. Assuming Standard Model W boson decay branching fractions, the W-pair
production cross section is measured to be sigmaWW = 16.30 +- 0.34(stat.) +-
0.18(syst.) pb. When combined with previous OPAL measurements, the W boson
branching fraction to hadrons is determined to be 68.32 +- 0.61(stat.) +-
0.28(syst.) % assuming lepton universality. These results are consistent with
Standard Model expectations.Comment: 22 pages, 5 figures, submitted to Phys. Lett.
First Measurement of Z/gamma* Production in Compton Scattering of Quasi-real Photons
We report the first observation of Z/gamma* production in Compton scattering
of quasi-real photons. This is a subprocess of the reaction e+e- to
e+e-Z/gamma*, where one of the final state electrons is undetected.
Approximately 55 pb-1 of data collected in the year 1997 at an e+e-
centre-of-mass energy of 183 GeV with the OPAL detector at LEP have been
analysed. The Z/gamma* from Compton scattering has been detected in the
hadronic decay channel. Within well defined kinematic bounds, we measure the
product of cross-section and Z/gamma* branching ratio to hadrons to be
(0.9+-0.3+-0.1) pb for events with a hadronic mass larger than 60 GeV,
dominated by (e)eZ production. In the hadronic mass region between 5 GeV and 60
GeV, dominated by (e)egamma* production, this product is found to be
(4.1+-1.6+-0.6) pb. Our results agree with the predictions of two Monte Carlo
event generators, grc4f and PYTHIA.Comment: 18 pages, LaTeX, 5 eps figures included, submitted to Physics Letters
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