In the North American Cordillera, a system of margin-parallel strike-slip faults and ductile shear zones accommodated northward translation of accreted terranes between the Cretaceous and Eocene. Constraining the timing of displacement on these structures is important for understanding the evolution of strain accommodation along the Cordilleran margin. The western Idaho shear zone (WISZ) is a north-striking, dextral-transpressional shear zone that deformed the boundary between the North American margin and accreted terranes to the west. At the latitude of the Salmon River canyon (45 degrees 25 ' N), available timing constraints demonstrate that shearing in the WISZ most likely initiated at ca. 108-104 Ma and continued after ca. 91 Ma. To more precisely constrain the timing of ductile shearing, we present new U-Pb zircon crystallization ages from granitoid dikes that intruded the WISZ along the Salmon River canyon. Dikes that crystallized between ca. 112 Ma and 101 Ma were deformed by the steeply east-dipping ductile fabrics that were generated during WISZ shearing. Undeformed dikes that crosscut these steeply east-dipping ductile fabrics yielded crystallization ages of ca. 85 Ma, which brackets the timing of cessation of WISZ shearing. This is consistent with published ca. 83-81 Ma 40Ar/39Ar biotite ages from the WISZ that approximate the timing of cooling through the quartz crystal-plastic transition. Our new timing constraints are consistent with published estimates for the timing of shearing further to the south in the WISZ and support correlation of the WISZ with dextral-transpressional shear zones along-strike in northwestern Nevada and the Sierra Nevada batholith that share similar kinematics and timing (ca. 105-83 Ma).
In oxide memristors composed of a switching layer and an oxygen vacancy reservoir layer (VO layer), both layers are typically made up of homostructures of the same materials. A question arises: how microscopically are the memristor switching dynamics determined by the structure of these two layers? To answer this question, this work reports an exploratory study of the Vo layer in sub-2 nm memristors by stacking 5-7 constituent atomic heterostructured layers (or 0.6-0.8 nm in Vo layer thickness) of Al2O3 (pristine oxide with negligible VO), MgO and Ga2O3 (both containing considerable Vo). The study revealed an intriguing correlation between the atomic layer structure and the memristor switching dynamics, including both switching speed and endurance. Specifically, heterostructured MgO/Ga2O3 Vo layer outperformed its homostructured MgO or Ga2O3 counterparts with higher switching speed up to 2 orders of magnitude, and higher endurance and device yield by a significant margin. An in situ scanning probe spectroscopy study revealed that the heterostructure of MgO and Ga2O3 atomic layers contained comparable VO concentrations but different crystalline structures that can reduce the amount of unintended defects formed at the interface and within the above 2-3 atomic layers. This results in a distinct advantage to facilitate high-speed and high-efficiency VO drift from the VO layer to the switching layer, as illustrated in the high switching speed and endurance. This is however not readily available in homostructured VO layers as unintended defects extend through the entire VO layer, which negatively impacts the switching dynamics of the memristors. This result provides critical insights into the correlation between the atomic-scale device design and switching dynamics of ultrathin memristors for various applications of microelectronics and neuromorphic computing, in which switching dynamics play a vital role.
Hydropower management has altered discharge regimes of large rivers worldwide, reducing sediment mobilization and early-seral conditions essential for many riverine species. Spiny softshell turtles (Apalone spinifera) rely on alluvial habitats for nesting and may serve as sentinel species to assess the effects of regulated flow regimes and sediment dynamics. We compared nesting habitat availability, nest site characteristics, and population structure of A. spinifera in the free-flowing Yellowstone River and the hydropower-regulated Bighorn River in Montana. Supervised land-cover classification of Sentinel-2A satellite imagery was integrated with field surveys of 504 nests and demographic sampling of 496 turtles across two 85.5 river-kilometer study reaches. The Yellowstone River supported up to 7.6 times more potential nesting habitat than the Bighorn River, where nearly 80% of nests were concentrated at only nine aggregation sites. Nests were positively associated with gravel substrates (87%), large woody material (70%), and side channel accessibility (65%), which were all prevalent on the Yellowstone River. We calculated minimum nesting areas and quantified a range of nesting habitat availability that reflects differences in geomorphic complexity and sediment supply in each river (112-626 ha Yellowstone River, 50-82 ha Bighorn River). Demographic measures, including sex ratios, size classes, and catch-per-unit-effort, indicate recruitment challenges for the Bighorn River population. Remote-sensing of alluvial habitats combined with demographic assessments can help guide discharge strategies to restore conditions that support a diverse group of riverine species.
This research aims to explore how the image of a leisure attraction is formed from the perspectives of tourists who had a previous cultural leisure experience at the Moray Archaeological City in Cusco and to contrast this with the image projected by travel agencies. The study employed various software tools to process the contents of 1049 comments made on TripAdvisor by tourists who visited Moray between January 2022 and August 2023. Additionally, 15 websites of travel agencies offering tourist visits to Moray for cultural, leisure, and recreation purposes were analysed. The research utilised cluster network, textual network, and qualitative analyses with different software, including Leximancer for TripAdvisor reviews and tour agency websites. By examining and contrasting the similarities and differences between content generated through social media platforms and travel agency content, stimulating results are presented with critical implications for destination branding and advertising. Given the content available on travel-related social media platforms, travel agencies and tourism marketers must attend to social media, analyse and examine various perceptions and leisure-based traveller behaviours, and align their marketing and branding approaches for superior success. This research contributes to a new methodology model process in which a tourist image of a cultural destination could be better understood deeply through data mining, from the perceptions of many stakeholders, in this case, the tourists who previously visited the destination and the companies that promote the image of these places.
Scholars have promoted the importance of developing quality coach-athlete relationships since the early 2000s. However, the perspective of Black coaches has been absent from the literature. Therefore, this research study explored what makes for high-quality coach-athlete relationships for Black coaches. Nine high school football coaches from the Midwest of the United States completed a 60-90-minute semi-structured interview consisting of questions constructed using the 3C coach-athlete relationship model of closeness, commitment, and complementarity. A thematic qualitative research design was implemented. The results revealed three main themes: coaching characteristics, athlete characteristics, and maintenance strategies. Additionally, coaching characteristics had six subthemes (e.g., being a father figure), and athlete characteristics had four subthemes (e.g., athletes' academics). Results indicate that Black football coaches at the high school level can serve as parental role models who develop quality coach-athlete relationships by being aware of such issues as athletes' academic status, creating a caring and task-involving climate, and using authentic and transformational leadership approaches.
