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This study combines field structural analysis with thin‐section petrography, U‐Pb dating, and strontium, carbon and oxygen isotopic analysis of calcite fracture fills to constrain the evolution of the 2‐5 km scale paleofluid system around the faulted, plunging fold nose comprising the southern termination of the Gypsum Valley salt wall in the Paradox Basin, U.S.A. Brittle deformation in this region began with the formation of a down‐to‐the‐northeast, counter‐regional fault and then progressed into jointing and faulting in a radial pattern, followed by jointing in a concentric pattern. Coupled with increases in fracture abundance toward the faults, multiple stages of mineralization suggest that the faults served as efficient and long‐lived conduits for vertical fluid migration. Although fracture cement textures and calcite colour are variable throughout the area, the distribution of these characteristics does not correlate with fracture orientation, relative age, stratigraphic or structural position. Irrespective of the type of calcite comprising the fracture cements, δ13C values average near −7‰ (VPDB), whereas δ18O values cluster into groups whose averages are roughly 6‰ apart, with the more negative grouping stratigraphically restricted to fracture cements in Jurassic rocks. The stratigraphic segregation of δ18O values suggests the paleofluid system contained two distinct paleofluids, a more recent one comprised of meteoric waters and an older one comprising brine that originated in Pennsylvanian strata. 87Sr/86Sr ratios in fracture‐filling calcite cements indicate that the older fluid underwent fluid‐rock interaction with Permian strata and that this evolved fluid migrated upwards along the faults until the Triassic or Jurassic. Thereafter, fluid migrating along the faults was more meteoric and appears to have migrated downward along the faults, where it interacted with Permian strata. Consistent U‐Pb dates from carbonates precipitated from the older fluid suggest this stage of the paleofluid system was active around 240 Ma. Local burial history models and published temperatures for fracture cements elsewhere in the basin suggest the younger stage of the paleofluid system occurred during the Latest Cretaceous to Oligocene. This study highlights the spatial and temporal complexity of fluid systems in the vicinity of salt structures and emphasises the need to interpret them through careful integration of high resolution stratigraphic and structural data in the context of evolving salt tectonics. [ABSTRACT FROM AUTHOR]

Cell size is an important variable in the study of cellular growth, metabolism, and the cell cycle. The large size of Amoeba proteus and the ease with which it can be collected and cultured have made it a star in biology education—and it was a model for research on cell biology before the introduction of molecular genetic methods. Measuring the cytoplasmic density of a single amoeba without modern instrumentation seems like a difficult task, but this was done with supreme accuracy in the 1940s. The solution was based on the familiar Cartesian diver that is used to demonstrate Archimedes's principle. It required the fabrication of a tiny diver that would respond to the additional mass of a cell. Experiments using this method allowed investigators to study changes in size and density associated with feeding, starvation, and cell division. This research is an illustration of the ingenuity of cell biologists in the pre-molecular genetic era of their field, which is often overlooked by contemporary scientists. The consideration of the mass, density, and buoyancy of free-living amoebas encourages a new hypothesis about the evolution of testate amoebas. [ABSTRACT FROM AUTHOR]

Unlike the mechanism of ballistospore discharge, which was not solved until the 1980s, the operation of asci as pressurized squirt guns is relatively straightforward and was understood in the nineteenth century. Since then, mycologists have sought to understand how structural adaptations to asci have allowed the ascomycetes to expel spores of different shapes and sizes over distances ranging from a few millimeters to tens of centimeters. These modifications include the use of valves at the tips of asci that maintain ascus pressure and expel spores at the highest speeds, and gelatinous appendages that connect spores after release and create larger projectiles with greater momentum than single spores. Clever experiments in the twentieth century coupled with meticulous microscopic studies led investigators to understand how asci with complicated apical structures worked and mathematical models produced estimates of launch speeds. With the recent application of high-speed video microscopy, these inferences about ascus function have been tested by imaging the motion of spores on a microsecond timescale. These experiments have established that ascospore discharge is the fastest fungal movement and is among the fastest movements in biology. Beginning with the history of the study of asci, this review article explains how asci are pressurized, how spores are released, and how far spores travel after their release. We also consider the efficiency of ascospore discharge relative to the mechanism of ballistospore discharge and examine the way that the squirt gun mechanism has limited the morphological diversity of ascomycete fruit bodies. • Ascospore discharge is the fastest fungal movement. • Early ascus research inspired the most ingenious experiments in mycological history. • Ascospore and ballistospore discharge share the same underlying chemistry. [ABSTRACT FROM AUTHOR]

The idea that preformed Cooper pairs could exist in a superconductor at temperatures higher than its zero-resistance critical temperature (Tc) has been explored for unconventional, interfacial, and disordered superconductors, but direct experimental evidence is lacking. We used scanning tunneling noise spectroscopy to show that preformed Cooper pairs exist up to temperatures much higher than Tc in the disordered superconductor titanium nitride by observing an enhancement in the shot noise that is equivalent to a change of the effective charge from one to two electron charges. We further show that the spectroscopic gap fills up rather than closes with increasing temperature. Our results demonstrate the existence of a state above Tc that, much like an ordinary metal, has no (pseudo)gap but carries charge through paired electrons. [ABSTRACT FROM AUTHOR]

The interactions between salt diapirs, thrust welds and thrusts in contractional belts are poorly understood due to, first, the inability of seismic data to distinguish between thrusts and welds or resolve associated sub‐resolution deformation, and second, the paucity of good field examples. The Warraweena area in the Northern Flinders Ranges of South Australia contains examples of Neoproterozoic to Early Cambrian squeezed diapirs linked by steep reverse faults formed during the Delamerian Orogeny. Benefiting from good field exposures, we use geological mapping, cross‐section construction and conceptual structural models to assess the three‐dimensional geometry and evolution of the structures, the lateral transition from diapirs to linking faults and the variability of associated meso‐ and small‐scale deformation. Three discrete diapirs consist of narrow outcrops of Callanna Group megabreccia (Willouran in age) up to 5‐km long. Their diapiric origin is confirmed by local development of caprock, steepening of flanking strata in composite halokinetic sequences and reworked diapir and roof debris in adjacent strata. The surrounding rocks display only background levels of small‐scale deformation. In contrast, the linking faults show no evidence of precursor diapirism, have fault‐related anticlines up to 100s of m in wavelength in their hanging walls, and an associated increase in small‐scale deformation (i.e. millimetre to metre scale folds, fractures and shear fabrics). The transitions from diapirs to faults occur within less than 200 m as short thrust welds at the diapir terminations. The exposed structures are analogous to those found on the subsurface of other salt basins such as the Gulf of Mexico and the South Atlantic conjugate margins. The results of this work can aid geoscientists evaluating three‐way traps against squeezed diapirs, welds or faults, and can help them to predict the style and abundance of both halokinetic and small‐scale structures that are below seismic resolution. [ABSTRACT FROM AUTHOR]

Background: Numerous studies have investigated the importance of visual clarity in simulated athletic performance and, surprisingly, have observed that several sports-related tasks are resilient to low-tomoderate levels of retinal defocus. The purpose of this study was to determine the effect of myopic defocus on baseball batting performance, as well as the influence of gender, preferred hand, refractive error, and previous baseball experience. Methods: Thirty visually normal (visual acuity at least 20/20, stereoacuity better than 50 arc seconds of stereoacuity) young-adult participants were pitched 20 baseballs from a pitching machine under four conditions in a randomized order: plano (control), +1.00 D, +2.00 D, and +3.00 D. All participants were tested under binocular viewing conditions, with their habitual distance correction in place. Two independent observers graded the batting performance via a quality-of-contact score. Results: Batting performance was significantly reduced under +2.00 D and +3.00 D conditions, but not under the +1.00 D condition. The overall effect of retinal defocus was significant (F = 9.137, p < 0.001). Previous baseball experience yielded a statistically significant difference in performance, but neither refractive error, hand, order, nor gender significantly influenced performance. A high linear correlation between both observers was found (R2 = 0.99). Conclusion: This study demonstrated that baseball batting performance was resilient to low levels of retinal defocus for amateur baseball players. The threshold level of myopic defocus where performance declined appears to be lower for baseball than for other simulated sportsrelated activities in the literature, including golf putting, cricket batting, and basketball free throws, suggesting that the influence of myopic defocus on athletic performance is likely task-dependent. [ABSTRACT FROM AUTHOR]

The recent discovery of AV3Sb5 (A=K,Rb,Cs) has uncovered an intriguing arena for exotic Fermi surface instabilities in a kagome metal. Among them, superconductivity is found in the vicinity of multiple van Hove singularities, exhibiting indications of unconventional pairing. We show that the sublattice interference mechanism is central to understanding the formation of superconductivity in a kagome metal. Starting from an appropriately chosen minimal tight-binding model with multiple van Hove singularities close to the Fermi level for AV3Sb5, we provide a random phase approximation analysis of superconducting instabilities. Nonlocal Coulomb repulsion, the sublattice profile of the van Hove bands, and the interaction strength turn out to be the crucial parameters to determine the preferred pairing symmetry. Implications for potentially topological surface states are discussed, along with a proposal for additional measurements to pin down the nature of superconductivity in AV3Sb5. [ABSTRACT FROM AUTHOR]