251 research outputs found
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Landscape evolution associated with the 2014–2015 Holuhraun eruption in Iceland
The 2014–2015 Holuhraun eruption in Iceland developed between the outlet glacier Dyngjujökull and the Askja central volcano and extruded a bulk lava volume of over 1 km3 onto the floodplain of the Jökulsá á Fjöllum river, making it the largest effusive eruption in Iceland during the past 230 years. Time-series monitoring using a combination of traditional aerial imaging, unmanned aerial systems, and field-based geodetic surveys, established an unprecedented record of the hydrological response of the river system to this lava flow. We observed: (1) the formation of lava-dammed lakes and channels produced during dam-breaching events; (2) percolation of glacial meltwater into the porous and permeable lava, forming an ephemeral hydrothermal system that included hot pools and hot springs that emerged from the lava flow front; and (3) the formation of new seepage channels caused by upwelling of water around the periphery of the lava flow. The observations show that lava flows, like the one produced by the 2014–2015 Holuhraun eruption, can cause significant hydrological changes that continue for several years after the lava is emplaced. Documenting these processes is therefore crucial for our interpretation of volcanic landscapes and processes of lava–water interaction on both Earth and Mars
Healthcare-associated infections and antibiotic use in long-term care residents from two geographical regions in Switzerland.
The burden of healthcare-associated infections (HAIs) and antimicrobial use in Swiss long-term care facilities (LTCFs) is currently unknown. This study assessed the prevalence of HAIs and antibiotic use among LTCF residents in Switzerland.
A point-prevalence study was undertaken in LTCFs in eastern and western Switzerland from August to October 2019 according to the 'Healthcare-associated infections in long-term care facilities' (HALT) protocol. Characteristics of residents (age, sex, wounds, dementia, indwelling catheters) and institutions (specific factors, geographic region) were assessed. LTCF residents were screened for HAIs and current antibiotic treatment. Personal and institutional factors associated with HAIs were assessed.
In total, 1185 residents from 16 LTCFs (eight per geographic region) were screened for HAIs and antibiotic treatment. Median age was 87 years (interquartile range 79-91) and 71% were female. The prevalence of HAIs was 4.2% (west 4.3% vs east 4.2%; P=0.93), with mucocutaneous skin infections (36%) and respiratory tract infections (30%) being the most common. Independent risk factors for the presence of HAIs were presence of a chronic wound [odds ratio (OR) 2.4, 95% confidence interval (CI) 1.1-5.0; P=0.02] and being immobile (OR 1.8, 95% CI 1.0-3.3; P=0.04). Antibiotics were given to 2.9% of residents (west 3.9% vs east 1.8%; P=0.05) on the day of the survey. The most commonly prescribed antibiotics were amoxicillin-clavulanic acid and quinolones.
The prevalence of HAIs in Swiss LTCFs is similar to that in other European countries, whereas antibiotic consumption is lower. Further point-prevalence surveys on a broader scale are recommended to improve understanding of the burden of HAIs and antibiotic consumption in this setting
Skyrmion Lattice in a Doped Semiconductor
We report a comprehensive small angle neutron scattering study (SANS) of the
magnetic phase diagram of the doped semiconductor Fe_{1-x}Co_{x}Si for x=0.2
and 0.25. For magnetic field parallel to the neutron beam we observe a six-fold
intensity pattern under field-cooling, which identifies the A-phase of
Fe_{1-x}Co_{x}Si as a skyrmion lattice. The regime of the skyrmion lattice is
highly hysteretic and extents over a wide temperature range, consistent with
the site disorder of the Fe and Co atoms. Our study identifies Fe_{1-x}Co_{x}Si
is a second material after MnSi in which a skyrmion lattice forms and
establishes that skyrmion lattices may also occur in strongly doped
semiconductors
A Development Environment for Visual Physics Analysis
The Visual Physics Analysis (VISPA) project integrates different aspects of
physics analyses into a graphical development environment. It addresses the
typical development cycle of (re-)designing, executing and verifying an
analysis. The project provides an extendable plug-in mechanism and includes
plug-ins for designing the analysis flow, for running the analysis on batch
systems, and for browsing the data content. The corresponding plug-ins are
based on an object-oriented toolkit for modular data analysis. We introduce the
main concepts of the project, describe the technical realization and
demonstrate the functionality in example applications
The interaction studied via femtoscopy in p + Nb reactions at
We report on the first measurement of and correlations via
the femtoscopy method in p+Nb reactions at , studied with the High Acceptance Di-Electron Spectrometer
(HADES). By comparing the experimental correlation function to model
calculations, a source size for pairs of and a slightly
smaller value for of is extracted.
Using the geometrical extent of the particle emitting region, determined
experimentally with correlations as reference together with a source
function from a transport model, it is possible to study different sets of
scattering parameters. The correlation is proven sensitive to
predicted scattering length values from chiral effective field theory. We
demonstrate that the femtoscopy technique can be used as valid alternative to
the analysis of scattering data to study the hyperon-nucleon interaction.Comment: 12 pages, 11 figure
Production of Sigma{\pm}pi?pK+ in p+p reactions at 3.5 GeV beam energy
We study the production of Sigma^+-pi^+-pK^+ particle quartets in p+p
reactions at 3.5 GeV kinetic beam energy. The data were taken with the HADES
experiment at GSI. This report evaluates the contribution of resonances like
Lambda(1405$, Sigma(1385)^0, Lambda(1520), Delta(1232), N^* and K^*0 to the
Sigma^+- pi^-+ p K+ final state. The resulting simulation model is compared to
the experimental data in several angular distributions and it shows itself as
suitable to evaluate the acceptance corrections properly.Comment: 15 pages, 5 figure
Medium effects in proton-induced production at 3.5 GeV
We present the analysis of the inclusive production in p+p and p+Nb
collisions measured with the HADES detector at a beam kinetic energy of 3.5
GeV. Data are compared to the GiBUU transport model. The data suggest the
presence of a repulsive momentum-dependent kaon potential as predicted by the
Chiral Perturbation Theory (ChPT). For the kaon at rest and at normal nuclear
density, the ChPT potential amounts to MeV. A detailed tuning of
the kaon production cross sections implemented in the model has been carried
out to reproduce the experimental data measured in p+p collisions. The
uncertainties in the parameters of the model were examined with respect to the
sensitivity of the experimental results from p+Nb collisions to the in-medium
kaon potential.Comment: 13 pages, 14 figure
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