6,250 research outputs found
Dynamic simulations in SixTrack
The DYNK module allows element settings in SixTrack to be changed on a
turn-by-turn basis. This document contains a technical description of the DYNK
module in SixTrack. It is mainly intended for a developer or advanced user who
wants to modify the DYNK module, for example by adding more functions that can
be used to calculate new element settings, or to add support for new elements
that can be used with DYNK.Comment: Submission to CERN yellow report / conference proceeding, the 2015
collimation tracking code worksho
A Variational Sum-Rule Approach to Collective Excitations of a Trapped Bose-Einstein Condensate
It is found that combining an excitation-energy sum rule with Fetter's trial
wave function gives almost exact low-lying collective-mode frequencies of a
trapped Bose-Einstein condensate at zero temperature.Comment: 11 pages, 2 figures, Revte
Scaling properties of protein family phylogenies
One of the classical questions in evolutionary biology is how evolutionary
processes are coupled at the gene and species level. With this motivation, we
compare the topological properties (mainly the depth scaling, as a
characterization of balance) of a large set of protein phylogenies with a set
of species phylogenies. The comparative analysis shows that both sets of
phylogenies share remarkably similar scaling behavior, suggesting the
universality of branching rules and of the evolutionary processes that drive
biological diversification from gene to species level. In order to explain such
generality, we propose a simple model which allows us to estimate the
proportion of evolvability/robustness needed to approximate the scaling
behavior observed in the phylogenies, highlighting the relevance of the
robustness of a biological system (species or protein) in the scaling
properties of the phylogenetic trees. Thus, the rules that govern the
incapability of a biological system to diversify are equally relevant both at
the gene and at the species level.Comment: Replaced with final published versio
Opening the Window for Electroweak Baryogenesis
We perform an analysis of the behaviour of the electroweak phase transition
in the Minimal Supersymmetric Standard Model, in the presence of light stops.
We show that, in previously unexplored regions of parameter space, the order
parameter can become significantly larger than one, for values of
the Higgs and supersymmetric particle masses consistent with the present
experimental bounds. This implies that baryon number can be efficiently
generated at the electroweak phase transition. As a by-product of this study,
we present an analysis of the problem of colour breaking minima at zero and
finite temperature, and we use it to investigate the region of parameter space
preferred by the best fit to the present precision electroweak measurement
data, in which the left-handed stops are much heavier than the right-handed
ones.Comment: 16 pages, LaTeX + 4 figures, psfig. (uuencoded
Pure cervical radiculopathy due to spontaneous spinal epidural haematoma (SSEH): report of a case solved conservatively
Introduction: Spontaneous spinal epidural haematoma (SSEH) is widely recognised throughout the literature as a cause of myelopathy, radicular compression being very rarely reported. Surgical management is almost always recommended, especially in the cases of spinal cord compression. Conservative treatment is reported as a curiosity and only in the case of spontaneous improvement. This report presents the particular case of a 64-year-old patient undergoing anticoagulant therapy that had a cervical radiculopathy due to a SSEH confirmed by MRI. The patient improved spontaneously and symptoms were solved with unconventional conservative treatment and without stopping the anticoagulant therapy. Conclusions: Spontaneous epidural haematoma must be kept in mind when patients undergoing anticoagulant therapy have a sudden onset of cervicobrachialgia. Even though most spinal surgeons advocate surgical treatment, a conservative approach may lead to a complete recovery and may be considered as a good option in the case of radicular involvement. Discontinuation of the anticoagulant therapy may not always be needed, especially when the clinical syndrome improves spontaneously
Collective Thomson scattering measurements of fast-ion transport due to sawtooth crashes in ASDEX Upgrade
Sawtooth instabilities can modify heating and current-drive profiles and potentially increase fast-ion losses. Understanding how sawteeth redistribute fast ions as a function of sawtooth parameters and of fast-ion energy and pitch is hence a subject of particular interest for future fusion devices. Here we present the first collective Thomson scattering (CTS) measurements of sawtooth-induced redistribution of fast ions at ASDEX Upgrade. These also represent the first localized fast-ion measurements on the high-field side of this device. The results indicate fast-ion losses in the phase-space measurement volume of about 50% across sawtooth crashes, in good agreement with values predicted with the Kadomtsev sawtooth model implemented in TRANSP and with the sawtooth model in the EBdyna_go code. In contrast to the case of sawteeth, we observe no fast-ion redistribution in the presence of fishbone modes. We highlight how CTS measurements can discriminate between different sawtooth models, in particular when aided by multi-diagnostic velocity-space tomography, and briefly discuss our results in light of existing measurements from other fast-ion diagnostics
Forward Global Photometric Calibration of the Dark Energy Survey
Many scientific goals for the Dark Energy Survey (DES) require calibration of
optical/NIR broadband photometry that is stable in time and uniform
over the celestial sky to one percent or better. It is also necessary to limit
to similar accuracy systematic uncertainty in the calibrated broadband
magnitudes due to uncertainty in the spectrum of the source. Here we present a
"Forward Global Calibration Method (FGCM)" for photometric calibration of the
DES, and we present results of its application to the first three years of the
survey (Y3A1). The FGCM combines data taken with auxiliary instrumentation at
the observatory with data from the broad-band survey imaging itself and models
of the instrument and atmosphere to estimate the spatial- and time-dependence
of the passbands of individual DES survey exposures. "Standard" passbands are
chosen that are typical of the passbands encountered during the survey. The
passband of any individual observation is combined with an estimate of the
source spectral shape to yield a magnitude in the standard
system. This "chromatic correction" to the standard system is necessary to
achieve sub-percent calibrations. The FGCM achieves reproducible and stable
photometric calibration of standard magnitudes of stellar
sources over the multi-year Y3A1 data sample with residual random calibration
errors of per exposure. The accuracy of the
calibration is uniform across the DES footprint to
within . The systematic uncertainties of magnitudes in
the standard system due to the spectra of sources are less than
for main sequence stars with .Comment: 25 pages, submitted to A
Wnt signaling and Loxl2 promote aggressive osteosarcoma
Osteosarcoma (OS) is the most frequent primary malignant bone tumor in urgent need of better therapies. Using genetically
modified mouse models (GEMMs), we demonstrate that Wnt signaling promotes c-Fos-induced OS formation via the actions of the
collagen-modifying enzyme Loxl2. c-Fos/AP-1 directly regulates the expression of the Wnt ligands Wnt7b and Wnt9a in OS cells
through promoter binding, and Wnt7b and Wnt9a in turn promote Loxl2 expression in murine and human OS cells through the
transcription factors Zeb1 and Zeb2. Concordantly, inhibition of Wnt ligand secretion by inactivating the Wnt-less (Wls) gene in
osteoblasts in c-Fos GEMMs either early or in a therapeutic setting reduces Loxl2 expression and progression of OS. Wls-deficient
osteosarcomas proliferate less, are less mineralized and are enriched in fibroblastic cells surrounded by collagen fibers. Importantly,
Loxl2 inhibition using either the pan-Lox inhibitor BAPN or a specific inducible shRNA reduces OS cell proliferation in vitro and
decreases tumor growth and lung colonization in murine and human orthotopic OS transplantation models. Finally, OS
development is delayed in c-Fos GEMMs treated with BAPN or with specific Loxl2 blocking antibodies. Congruently, a strong
correlation between c-FOS, LOXL2 and WNT7B/WNT9A expression is observed in human OS samples, and c-FOS/LOXL2 coexpression correlates with OS aggressiveness and decreased patient survival. Therefore, therapeutic targeting of Wnt and/or
Loxl2 should be considered to potentiate the inadequate current treatments for pediatric, recurrent, and metastatic OS
Chemical Abundance Analysis of Tucana III, the Second -process Enhanced Ultra-Faint Dwarf Galaxy
We present a chemical abundance analysis of four additional confirmed member
stars of Tucana III, a Milky Way satellite galaxy candidate in the process of
being tidally disrupted as it is accreted by the Galaxy. Two of these stars are
centrally located in the core of the galaxy while the other two stars are
located in the eastern and western tidal tails. The four stars have chemical
abundance patterns consistent with the one previously studied star in Tucana
III: they are moderately enhanced in -process elements, i.e. they have
0.4 dex. The non-neutron-capture elements generally
follow trends seen in other dwarf galaxies, including a metallicity range of
0.44 dex and the expected trend in -elements, i.e., the lower
metallicity stars have higher Ca and Ti abundance. Overall, the chemical
abundance patterns of these stars suggest that Tucana III was an ultra-faint
dwarf galaxy, and not a globular cluster, before being tidally disturbed. As is
the case for the one other galaxy dominated by -process enhanced stars,
Reticulum II, Tucana III's stellar chemical abundances are consistent with
pollution from ejecta produced by a binary neutron star merger, although a
different -process element or dilution gas mass is required to explain the
abundances in these two galaxies if a neutron star merger is the sole source of
-process enhancement.Comment: 18 pages, 10 figures; accepted by Ap
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