Digital shinrin-yoku: do nature experiences in virtual reality reduce stress and increase well-being as strongly as similar experiences in a physical forest?

Virtual Reality - Shinrin-yoku or forest bathing refers to a therapeutic, immersive nature experience that aids to improve well-being. The goal of the current research was to compare the effects of...     

Extending a brainiac prover to lambda-free higher-order logic

Decades of work have gone into developing efficient proof calculi, data structures, algorithms, and heuristics for first-order automatic theorem proving. Higher-order provers lag behind in terms of efficiency. Instead of developing a new higher-order prover from the ground up, we propose to start with the state-of-the-art superposition prover E and gradually enrich it with higher-order features. We explain how to extend the prover’s data structures, algorithms, and heuristics to \(\lambda \)-free higher-order logic, a formalism that supports partial application and applied variables. Our extension outperforms the traditional encoding and appears promising as a stepping stone toward full higher-order logic.

     

Countercurrent chromatography isolation of 11′-γ-tocomonoenol from pumpkin seed oil with detection of novel minor tocochromanols

A non-refined, organic pumpkin seed oil (PSO) was chosen for the isolation and structure verification of the rare vitamin E compound γ-tocomonoenol (γ-T1). Initial measurements indicated the presence of ~0.4 mg γ-T1 per 100 g PSO. Saponification of ~2 L of PSO, followed by repeated countercurrent chromatography (CCC) with the solvent system n-hexane/benzotrifluoride/acetonitrile (v/v/v) and silica gel column chromatography enabled the isolation of 6.8 mg γ-T1 with a purity of 96.0% according to gas chromatography with mass spectrometry (GC/MS) analysis. Structural analysis by ¹H nuclear magnetic resonance (NMR) spectroscopy and GC/MS of the γ-T1 isolate confirmed the presence of a double bond in C-11′-position (11′-γ-tocomonoenol). In addition, CCC fractionation enabled the detection of 18 different tocochromanols, many of which were reported for the first time in PSO. This unmatched variety included among others α-/γ-tocopherol, α-/γ-tocomonoenol, two α- and two γ-tocodienol isomers, α-/γ-tocotrienol as well as the rare 11′-β-tocomonoenol (β-T1) and δ-T1. Three uncommon tocochromanols were also detected whose origins and structure remained unclear.     

Emergence of Nontrivial Low-Energy Dirac Fermions in Antiferromagnetic EuCd2As2

Parity-time symmetry plays an essential role for the formation of Dirac states in Dirac semimetals. So far, all of the experimentally identified topologically nontrivial Dirac semimetals (DSMs) possess both parity and time reversal symmetry. The realization of magnetic topological DSMs remains a major issue in topological material research. Here, combining angle-resolved photoemission spectroscopy with density functional theory calculations, it is ascertained that band inversion induces a topologically nontrivial ground state in EuCd₂As₂. As a result, ideal magnetic Dirac fermions with simplest double cone structure near the Fermi level emerge in the antiferromagnetic (AFM) phase. The magnetic order breaks time reversal symmetry, but preserves inversion symmetry. The double degeneracy of the Dirac bands is protected by a combination of inversion, time-reversal, and an additional translation operation. Moreover, the calculations show that a deviation of the magnetic moments from the c-axis leads to the breaking of C3 rotation symmetry, and thus, a small bandgap opens at the Dirac point in the bulk. In this case, the system hosts a novel state containing three different types of topological insulator: axion insulator, AFM topological crystalline insulator (TCI), and higher order topological insulator. The results provide an enlarged platform for the quest of topological Dirac fermions in a magnetic system.     

Geothermal Energy Potential of Active Northern Underground Mines: Designing a System Relying on Mine Water

Mine Water and the Environment - Mines in northern regions must heat underground workings, surface buildings, or process water due to frigid weather conditions. Mining companies commonly use fossil...     

Polyaluminum chloride with high Al30 content as removal agent for arsenic-contaminated well water

Polyaluminum chloride (PACl) is a well-established coagulant in water treatment with high removal efficiency for arsenic. A high content of Al₃₀ nanoclusters in PACl improves the removal efficiency over broader dosage and pH range. In this study we tested PACl with 75% Al₃₀ nanoclusters (PACl_Al30) for the treatment of arsenic-contaminated well water by laboratory batch experiments and field application in the geothermal area of Chalkidiki, Greece, and in the Pannonian Basin, Romania. The treatment efficiency was studied as a function of dosage and the nanoclusters’ protonation degree. Acid-base titration revealed increasing deprotonation of PACl_Al30 from pH 4.7 to the point of zero charge at pH 6.7. The most efficient removal of As(III) and As(V) coincided with optimal aggregation of the Al nanoclusters at pH 7-8, a common pH range for groundwater. The application of PACl_Al30 with an Al_tot concentration of 1-5 mM in laboratory batch experiments successfully lowered dissolved As(V) concentrations from 20 to 230 μg/L to less than 5 μg/L. Field tests confirmed laboratory results, and showed that the WHO threshold value of 10 μg/L was only slightly exceeded (10.8 μg/L) at initial concentrations as high as 2300 μg/L As(V). However, As(III) removal was less efficient (<40%), therefore oxidation will be crucial before coagulation with PACl_Al30. The presence of silica in the well water improved As(III) removal by typically 10%. This study revealed that the Al₃₀ nanoclusters are most efficient for the removal of As(V) from water resources at near-neutral pH.     

Sparse matrix operations on several multi-core architectures

This paper compares various contemporary multicore-based microprocessor architectures from different vendors with different memory interconnects regarding performance, speedup, and parallel efficiency. Sparse matrix decomposition is used as a benchmark application. The example matrix used in the experiments comes from an electrical engineering application, where numerical simulation of physical processes plays an important role in the design of industrial products.     

Age-dependent changes in microscale stiffness and mechanoresponses of cells

Cellular ageing can lead to altered cell mechanical properties and is known to affect many fundamental physiological cell functions. To reveal age-dependent changes in cell mechanical properties and in active mechanoresponses, the stiffness of human fibroblasts from differently aged donors was determined, as well as the cell's reaction to periodic mechanical deformation of the culture substrate, and the two parameters were correlated. A comparison of the average Young's moduli revealed that cells from young donors (<25 years) are considerably stiffer than cells from older donors (>30 years). The reduced stiffness of cells from the older donor group corresponds to the measured decrease of actin in these cells. Remarkably, cells from the older donor group show a significantly faster reorganization response to periodic uniaxial tensile strain than cells from the young donor group. The impact of a reduced amount of actin on cell stiffness and cell reorganization kinetics is further confirmed by experiments where the amount of cellular actin in cells from the young donor group was decreased by transient siRNA knockdown of the actin gene. These cells show a reduced stiffness and enhanced reorganization speed, and in this way mimic the properties and behavior of cells from the older donor group. These results demonstrate that mechanical properties of human fibroblasts depend on the donor's age, which in turn may affect the cells' active responses to mechanical stimulations.     

Low-intensity Husbandry as a Cost-efficient Way to Preserve Dry Grasslands

Abstract

Dry grasslands represent unique ecosystems that are known for high biodiversity. Land use changes have led to a decline in Europe. Shrub encroachment is a major problem in incorrectly or unmanaged areas, and affects not only flora and fauna but also leads to changes in the appearance of the landscape. Our study was conducted on the island of Hiddensee, north-east Germany, where today dry grasslands are endangered by shrub encroachment. We analysed the current land use under consideration of farming costs as well as current agricultural subsidies. Our results show that revenues of low-intensity cattle husbandry only account for 61% of total costs and that farming becomes profitable only with subsidies. Our study illustrates that goats can be a cost-efficient solution for areas with high shrub cover in contrast to manual clearing. The maintenance of dry grasslands is therefore more cost-efficient with grazing animals than with technical-manual labour.