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Although similar to more commonly implemented single wavelength approaches, broadband pump‐probe or transient absorption microscopy presents unique experimental challenges due to the simultaneous requirements of a broadband probe pulse and a small sample volume. Here we provide an in‐depth analysis of broadband detection schemes and their common noise sources to provide strategies for balancing the conflicting needs of high sensitivity and low probe fluence. We show that broadband pump‐probe microscopy is atypically sensitive to laser shot noise and therefore, low pump on/off modulation frequencies, on the order of 100 s of Hz to a few kHz, are essential to measure small (~10^-3 - 10^-4) amplitude transient spectra while remaining in the perturbative limit. 

Abstract Relative to their limited areal extent, riparian ecosystems are disproportionately important in regulating inorganic solute export from agricultural landscapes. We investigated spatial patterns of solute concentrations in surface and ground waters of stream corridors to infer the dominant hydrologic transport and biogeochemical pathways that influence riparian nitrate and sulfate processing from uplands to streams. We selected three reaches of stream corridors draining an agricultural landscape that vary in hydrologic connection with upland aquifers. Non‐irrigated crop production dominates land use in the study area and influences the quality of upland groundwater draining to the stream corridors. We interpret patterns in solute concentrations of riparian groundwater and stream water relative to upland groundwater to infer the influences of biogeochemical processing and hydrologic connectivity. Excess nitrate from cultivated soils is evident in upland groundwater concentrations that consistently exceed the U.S. Environmental Protection Agency public drinking water standard. Nitrate and oxygen concentrations in riparian groundwaters were consistently lower than in terrace groundwater and adjacent stream waters, suggesting rapid consumption of oxygen and influence of anaerobic metabolic reduction processes in subsurface flow. Sulfate concentrations in streams were higher than in terrace groundwater, likely due to weathering of shale‐derived substrate in riparian aquifers. The degree of solute mitigation or augmentation by riparian biogeochemical processes depended on the geomorphic context that controlled the fraction of upland water passing through the riparian substrate. Observed net nitrate losses with net sulfate gains from uplands to stream channels reflect flow paths through a complex distribution of redox conditions throughout the riparian areas, emphasizing the importance of considering riparian area heterogeneity in predicting solute export in streams. This research contributes to understanding how stream corridor substrate and geomorphic context controls the biogeochemical and hydrologic processes influencing the quality of water exported from agricultural landscapes. 

Abstract Elemental sulfur (S₈⁰)‐oxidising Sulfolobales (Archaea) dominate high‐temperature acidic hot springs (>80°C, pH <4). However, genomic analyses of S₈⁰‐oxidising members of the Sulfolobales reveal a patchy distribution of genes encoding sulfur oxygenase reductase (SOR), an S₈⁰disproportionating enzyme attributed to S₈⁰oxidation. Here, we report the S₈⁰‐dependent growth of two Sulfolobales strains previously isolated from acidic hot springs in Yellowstone National Park, one of which associated with bulk S₈⁰during growth and one that did not. The genomes of each strain encoded different sulfur metabolism enzymes, with only one encoding SOR. Dialysis membrane experiments showed that direct contact is not required for S₈⁰oxidation in the SOR‐encoding strain. This is attributed to the generation of hydrogen sulfide (H₂S) from S₈⁰disproportionation that can diffuse out of the cell to solubilise bulk S₈⁰to form soluble polysulfides (S_x²⁻) and/or S₈⁰nanoparticles that readily diffuse across dialysis membranes. The Sulfolobales strain lacking SOR required direct contact to oxidise S₈⁰, which could be overcome by the addition of H₂S. High concentrations of S₈⁰inhibited the growth of both strains. These results implicate alternative strategies to acquire and metabolise sulfur in Sulfolobales and have implications for their distribution and ecology in their hot spring habitats. 

Structured classroom observation protocols provide instructors with data about their teaching practices, but instructors may not meaningfully engage with those data without guidance. To facilitate instructor reflection, educational developers from the Centers for Teaching and Learning (CTLs) and educational researchers from STEM departments across three campuses collaborated to design and implement a novel faculty professional development program that would promote reflection on teaching using instructors’ Classroom Observation Protocol for Undergraduate STEM (COPUS; Smith et al., 2013) data—a program we call data-informed professional development (DIPD). The program involved faculty completion of/participation in a teaching reflection, structured classroom observations from two course sessions, at least one meeting with CTL staff, an exit interview, and an opportunity to update their original teaching reflection. Through qualitatively coding the post-DIPD exit interviews, we found that instructors primarily reflected on their COPUS data with a desire to increase student engagement. Instructors also described being more open to making small changes to their courses, feeling supported to make changes to their teaching, and feeling that there was an important element of community-building in the DIPD program. And finally, instructors described how the DIPD experience was beneficial for promoting reflection on teaching practices, but the meeting portion was critical–providing data from the structured observations alone was not sufficient for a variety of reasons. Our study can serve as a teaching professional development model for how educational developers and education researchers can collaborate to prompt instructors to critically reflect on their teaching practices using structured observation protocols.  

Abstract The withdrawal of glaciers in mountainous systems exposes over‐steepened slopes previously sculpted by ice. This debuttressing can directly trigger mass movements or leave slopes susceptible to them by other drivers, including seismogenic shaking and changing climate conditions. These systems may pose hazards long after deglaciation. Here, we investigate the drivers of slope failure for landslides at the northern entrance to Yellowstone National Park, a critical conduit traversed by ~1 million visitors each year. Through field mapping and analyses of LiDAR data, we quantify the spatial and temporal relationships between eight adjacent slides. Stratigraphic relationships and surface roughness analyses suggest initial emplacement 13–11.5 ka, after a significant delay from Deckard Flats glacial retreat (15.1 ± 1.2 ka). Thus, rapid glacial debuttressing was not the direct trigger of slope failure, though the resultant change in stress regime likely had a preparatory influence. We posit that the timing of failure was associated with (1) a period of enhanced moisture and seismicity in the late Pleistocene and (2) altered stress regimes associated with ice retreat. Historical archives and cross‐cutting relationships indicate portions of some ancient slides were reactivated; these areas are morphologically distinguishable from other slide surfaces, with mean topographic roughness 2 times that of non‐active slides. Stream power analysis and archival records indicate Holocene incision of the Gardner River and human disturbances are largely responsible for modern reactivations. Our findings highlight the importance of combining archival records with stratigraphic, field and remote sensing approaches to understanding landslide timing, risk, and drivers in post‐glacial environments. This study also provides a valuable baseline for geomorphic change in the Yellowstone system, where a 2022 flood incised streams, damaged infrastructure and further reactivated landslide slopes. 

Abstract Large carnivores such as the lion are declining across Africa, in part because their large herbivore prey is declining. There is consensus that increased protection from prey depletion will be necessary to reverse the decline of lion populations, but few studies have tested whether increased protection is sufficient to reverse the decline, particularly in the large, open ecosystems where most lions remain. Here, we used an integrated population model to test whether lion demography and population dynamics were measurably improved by increased protection. We used data from monitoring of 358 individuals from 2013 to 2021 in the Greater Kafue Ecosystem, where prior research showed that lions were strongly limited by prey depletion, but protection increased in several well‐defined areas beginning in 2018. In some other areas, protection decreased. In areas with high protection, lion fecundity was 29% higher, and mean annual apparent survival (φ) was 8.3% higher (with a minimum difference of 6.0% for prime‐aged adult females and a maximum difference of 11.9% for sub‐adult males). These demographic benefits combined to produce likely population growth in areas with high protection ( = 1.085, 90% CI = 0.97, 1.21), despite likely population decline in areas with low protection ( = 0.970, 90% CI = 0.88, 1.07). For the ecosystem as a whole, population size remained relatively constant at a moderate density of 3.74 (±0.49 SD) to 4.13 (±0.52 SD) lions/100 km². With the growth observed in areas with high protection, the expected doubling time was 10 years. Despite this, recovery at the scale of the entire ecosystem is likely to be slow without increased protection; the current growth rate would require 50 years to double. Our results demonstrate that increased protection is likely to improve the reproduction and population growth rate of lions at a large scale within an unfenced ecosystem that has been greatly affected by poaching.