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Soil structure dynamics during a season depend on management practices and environmental factors. A lightweight autonomous robot (total mass: 3300–4100 kg, wheel load: 700–1200 kg, contact areas: 0.125 m², inflation pressures: 60–280 kPa) was used for sowing (October 2021) and weeding (May 2022) operations on an annually plowed sandy loam field. We took 579 cm³ soil cores at 10- to 18-cm depth in the crop area and wheel tracks before and after the operations to assess the impact from traffic and the potential recovery of topsoil structural properties. We measured air permeability and effective air-filled porosity in the laboratory, and X-ray CT scanned the samples to evaluate soil pore functionality. The first operation (conducted on a moist seedbed) had the largest impact, significantly compacting and reducing the air-filled porosity by 42% (from 0.21 to 0.12 m³ m−3) and decreasing air permeability by 75.8% (from 130 to 31.5 μm²). After 7 months, the crop area and wheel track showed signs of soil consolidation due to environmental factors but not decompaction. The second operation occurred on drier (water content 0.06 g g−1), stronger soil conditions (degree of compactness 100.8%), and recompaction of the wheel track was not observed. Traffic in weak soils can result in seasonal topsoil compaction despite the lighter wheel loads. However, due to the milder impacts, recovery rates might be faster for lightweight machinery than for heavy tractors. Multi-season studies are needed to assess the real potential of lightweight robots to minimize soil compaction risk. [ABSTRACT FROM AUTHOR]

Most superconductors have an isotropic, single component order parameter and are well described by the standard (BCS) theory for superconductivity. Unconventional, multiple-component superconductors are exceptionally rare and are much less understood. Here, we combine scanning tunneling microscopy and angle-resolved macroscopic transport for studying the candidate chiral superconductor, 4Hb-TaS2. We reveal quasi-periodic one-dimensional modulations in the tunneling conductance accompanied by two-fold symmetric superconducting critical field. The strong modulation of the in-plane critical field, Hc2, points to a nematic, unconventional order parameter. However, the imaged vortex core is isotropic at low temperatures. We suggest a model that reconciles this apparent discrepancy and takes into account previously observed spontaneous time-reversal symmetry breaking at low temperatures. The model describes a competition between a dominating chiral superconducting order parameter and a nematic one. The latter emerges close to the normal phase. Our results strongly support the existence of two-component superconductivity in 4Hb-TaS2 and can provide valuable insights into other systems with coexistent charge order and superconductivity. I. Silber et al. discover a two-fold symmetry of the superconducting upper critical field in hexagonal 4Hb-TaS2 just below Tc, a clear signature of nematic, two-component superconductivity. They further suggest a theoretical model that reconciles the nematic superconductivity with the previously-observed time-reversal-symmetry-breaking in this material. [ABSTRACT FROM AUTHOR]

The study examined the unique contribution of both personal characteristics and several types of exposure variables to the adjustment of Israeli adolescents following the Second Lebanon War. Two thousand three hundred and fourteen adolescents, who lived in areas that were the target of multiple missile attacks, completed self-report questionnaires assessing personal characteristics of gender and early traumatic events, subjective exposure (i.e., measures of fear and shortage of basic necessities during the war), objective exposure (i.e., exposure to missile attacks, knowing someone who was wounded or killed) and media exposure. Fifteen percent of the adolescents reported moderate or severe post-traumatic symptoms. Girls and adolescents who experienced earlier traumatic events were at higher risk for distress. While the level of direct exposure contributed to greater distress, the contribution of subjective exposure was significantly stronger. The discussion deals with the unique contribution of both subjective and objective characteristics to post-war adjustment. (Contains 3 tables.)