1,309 research outputs found
Gravitational-wave signals from 3D supernova simulations with different neutrino-transport methods
We compare gravitational-wave (GW) signals from eight three-dimensional simulations of core-collapse supernovae from Glas et al. (2019), using two different progenitors with zero-age main sequence masses of 9 and 20 solar masses. The collapse of each progenitor was simulated four times, at two different grid resolutions and with two different neutrino transport methods, using the Aenus-Alcar code. The main goal of this study is to assess the validity of recent concerns that the so-called "Ray-by-Ray+" (RbR+) approximation is problematic in core-collapse simulations and can adversely affect theoretical GW predictions. Therefore, signals from simulations using RbR+ are compared to signals from corresponding simulations using a fully multidimensional (FMD) transport scheme. The 9 solar-mass progenitor successfully explodes, whereas the 20 solar-mass model does not. Both the standing accretion shock instability and hot-bubble convection develop in the postshock layer of the non-exploding models. In the exploding models, neutrino-driven convection in the postshock flow is established around 100 ms after core bounce and lasts until the onset of shock revival. We can, therefore, judge the impact of the numerical resolution and neutrino transport under all conditions typically seen in non-rotating core-collapse simulations. We find excellent qualitative agreement in all GW features and mostly very satisfactory quantitative agreement between simulations using the different transport schemes. Overall, resolution-dependent differences in the hydrodynamic behaviour of low-resolution and high-resolution models turn out to have a greater impact on the GW signals than consequences of the different transport methods. Furthermore, increasing the resolution decreases the discrepancies between models with different neutrino transport
Inflammatory bowel disease-specific autoantibodies in HLA-B27-associated spondyloarthropathies: Increased prevalence of ASCA and pANCA
Aims: An association between inflammatory bowel disease (IBD) and spondyloarthropathies (SpA) has repeatedly been reported. The aim of the present study was to investigate whether serologic markers of IBD, e. g. antibodies against Saccharomyces cerevisiae (ASCA), antibodies against exocrine pancreas (PAB) and perinuclear antineutrophil cytoplasmic antibodies (pANCA) are present in HLA-B27-associated SpA. Methods: 87 patients with HLA-B27-positive SpA and 145 controls were tested for ASCA, PAB and pANCA employing ELISA or indirect immunofluorescence, respectively. Antibody-positive patients were interviewed regarding IBD-related symptoms using a standardized questionnaire. Results/Conclusion: When compared to the controls, ASCA IgA but not ASCA IgG levels were significantly increased in patients with SpA, in particular in ankylosing spondylitis (AS) and undifferentiated SpA (uSpA). pANCA were found in increased frequency in patients with SpA whereas PAB were not detected. The existence of autoantibodies was not associated with gastrointestinal symptoms but sustains the presence of a pathophysiological link between bowel inflammation and SpA. Copyright (C) 2004 S. Karger AG, Basel
On-the-fly memory compression for multibody algorithms.
Memory and bandwidth demands challenge developers of particle-based codes that have to scale on new architectures, as the growth of concurrency outperforms improvements in memory access facilities, as the memory per core tends to stagnate, and as communication networks cannot increase bandwidth arbitrary. We propose to analyse each particle of such a code to find out whether a hierarchical data representation storing data with reduced precision caps the memory demands without exceeding given error bounds. For admissible candidates, we perform this compression and thus reduce the pressure on the memory subsystem, lower the total memory footprint and reduce the data to be exchanged via MPI. Notably, our analysis and transformation changes the data compression dynamically, i.e. the choice of data format follows the solution characteristics, and it does not require us to alter the core simulation code
Performance differences between TIMSS’s paper-pencil test and tablet test of Dutch grade 4 students:Results from the eTIMSS Equivalence study.
Psychometric Framework for Modeling Parental Involvement and Reading Literacy
Assessment, Testing and Evaluatio
Towards an optimal therapy strategy for myogenous TMD, physiotherapy compared with occlusal splint therapy in an RCT with therapy-and-patient-specific treatment durations
Psychometric Framework for Modeling Parental Involvement and Reading Literacy
Assessment, Testing and Evaluatio
Carboxylate ion pairing with alkali-metal ions for β-Lactoglobulin and its role on aggregation and interfacial adsorption
We
report a combined experimental and computational study of the
whey protein β-lactoglobulin (BLG) in different electrolyte
solutions. Vibrational sum-frequency generation (SFG) and ellipsometry
were used to investigate the molecular structure of BLG modified air–water
interfaces as a function of LiCl, NaCl, and KCl concentrations. Molecular
dynamics (MD) simulations and thermodynamic integration provided details
of the ion pairing of protein surface residues with alkali-metal cations.
Our results at pH 6.2 indicate that BLG at the air–water interface
forms mono- and bilayers preferably at low and high ionic strength,
respectively. Results from SFG spectroscopy and ellipsometry are consistent
with intimate ion pairing of alkali-metal cations with aspartate and
glutamate carboxylates, which is shown to be more effective for smaller
cations (Li<sup>+</sup> and Na<sup>+</sup>). MD simulations show not
only carboxylate–alkali-metal ion pairs but also ion multiplets
with the alkali-metal ion in a bridging position between two or more
carboxylates. Consequently, alkali-metal cations can bridge carboxylates
not only within a monomer but also between monomers, thus providing
an important dimerization mechanism between hydrophilic surface patches
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