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

Centrality dependence of subthreshold ϕ\phi meson production in Ni+Ni collisions at 1.9A GeV

We analysed the $\phi$ meson production in central Ni+Ni collisions at the beam kinetic energy of 1.93A GeV with the FOPI spectrometer and found the production probability per event of $[8.6 ~\pm~ 1.6 ~(\text{stat}) \pm 1.5 ~(\text{syst})] \times 10^{-4}$. This new data point allows for the first time to inspect the centrality dependence of the subthreshold $\phi$ meson production in heavy-ion collisions. The rise of $\phi$ meson multiplicity per event with mean number of participants can be parameterized by the power function with exponent $\alpha = 1.8 \pm 0.6$. The ratio of $\phi$ to $\text{K}^-$ production yields seems not to depend within the experimental uncertainties on the collision centrality, and the average of measured values was found to be $0.36 \pm 0.05$.Comment: 9 pages, 5 figure

Strange meson production in Al+Al collisions at 1.9A GeV

The production of K$^+$, K$^-$ and $\varphi$(1020) mesons is studied in Al+Al collisions at a beam energy of 1.9A GeV which is close or below the production threshold in NN reactions. Inverse slopes, anisotropy parameters, and total emission yields of K$^{\pm}$ mesons are obtained. A comparison of the ratio of kinetic energy distributions of K$^-$ and K$^+$ mesons to the HSD transport model calculations suggests that the inclusion of the in-medium modifications of kaon properties is necessary to reproduce the ratio. The inverse slope and total yield of $\phi$ mesons are deduced. The contribution to K$^-$ production from $\phi$ meson decays is found to be [17 $\pm$ 3 (stat) $^{+2}_{-7}$ (syst)] %. The results are in line with previous K$^{\pm}$ and $\phi$ data obtained for different colliding systems at similar incident beam energies.Comment: 16 pages, 11 figure

The Λp\bf{\Lambda p} interaction studied via femtoscopy in p + Nb reactions at sNN=3.18 GeV\mathbf{\sqrt{s_{NN}}=3.18} ~\mathrm{\bf{GeV}}

We report on the first measurement of $p\Lambda$ and $pp$ correlations via the femtoscopy method in p+Nb reactions at $\mathrm{\sqrt{s_{NN}}=3.18} ~\mathrm{GeV}$, studied with the High Acceptance Di-Electron Spectrometer (HADES). By comparing the experimental correlation function to model calculations, a source size for $pp$ pairs of $r_{0,pp}=2.02 \pm 0.01(\mathrm{stat})^{+0.11}_{-0.12} (\mathrm{sys}) ~\mathrm{fm}$ and a slightly smaller value for $p\Lambda$ of $r_{0,\Lambda p}=1.62 \pm 0.02(\mathrm{stat})^{+0.19}_{-0.08}(\mathrm{sys}) ~\mathrm{fm}$ is extracted. Using the geometrical extent of the particle emitting region, determined experimentally with $pp$ correlations as reference together with a source function from a transport model, it is possible to study different sets of scattering parameters. The $p\Lambda$ 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