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Cobaloxime-Based Metalloradical Catalysis: A Versatile Strategy for the Synthesis of Cyclopropenes and Oxazoles
No full textMetalloradical catalysis (MRC), predominantly exemplified by metalloporphyrin complexes, has emerged as a promising strategy for regulating radical reactions and broadening their synthetic applications. Here, an efficient catalytic method has been devised for the radical [2 + 1] cyclopropenation of alkynes and radical [3 + 2] oxazolation of nitriles using α-aryldiazoacetates via MRC. Cobaloxime proves effective in facilitating the metalloradical [2 + 1] cyclopropenation of alkynes and radical [3 + 2] oxazolation cycloaddition reaction under mild conditions. The reactions demonstrate broad substrate tolerance, accommodating gram-scale transformations and the synthesis of pharmaceutical com-pounds. Our findings highlight the significant potential of cobaloxime-catalyzed cycloaddition as a valuable tool in organic synthesis and broaden the scope of metalloradical systems in catalysis
Impacts of Irrigation System, Irrigation Rate, And Cultivar on Hemp Production in the Semiarid Intermountain West
No full textThe industrial hemp (Cannabis sativa L.) industry rapidly emerged in Utah in 2019 with nearly 480 ha of production. Production declined rapidly due to flooded floral hemp markets, but the industry is still viable in the state. Two of the most pressing questions about hemp management among growers in this region include cultivar selection and irrigation management. An outdoor hemp research trial was established in 2020 near Logan, UT (41.66 N, −111.91 W), to investigate fundamental irrigation strategies and cultivar performance. This trial (2020–2021) examined combinations of three hemp cultivars, four irrigation technologies, and three irrigation rates (100%, 75%, 50% of estimated evapotranspiration of corn [Zea mays L.] given lack of data for hemp) nested within each irrigation technology. Female hemp clones were transplanted in late May and harvested in September and October based on flower maturity. The irrigation technology (mid-, low-elevation spray, low-elevation precision application, and mobile drip) had no significant impacts on hemp yield or cannabinoid concentrations. Hemp biomass yield and cannabidiol concentrations often increased with less applied irrigation in all irrigation technologies. The three hemp cultivars responded similarly to irrigation management, although there was high plant-to-plant variability in delta 9 tetrahydrocannabinol (THC) concentrations. This research suggested that floral hemp could be irrigated less than other crops in the region, and irrigation requirements among some hemp cultivars may be similar. Further, robust and representative sampling protocols for THC monitoring are needed to ensure variability is accounted for
Enhancing Student Engagement in Numerical Methods: The Impact of Alternative Grading Practices
No full textAccess the online Pressbooks version of this introduction here.
Student engagement is critical for achieving positive academic and social outcomes. However, maintaining high engagement levels in challenging math-based courses like numerical methods can be difficult. This study addresses this challenge by implementing two assessment-based strategies: a bonus point self-assessment rubric and peer evaluations. These interventions aim to incentivize engagement and reward essential skills such as effort and teamwork, which are often overlooked by traditional grading systems but are crucial for success beyond the classroom. While existing research highlights the potential benefits of self-assessments and peer evaluations, there is limited evidence on their use in technical courses like numerical methods. Additionally, few studies have explored how these strategies impact specific outcomes such as engagement, anxiety, and learning in a higher education STEM context. This study aims to address these gaps by investigating the effectiveness of bonus point self-assessment rubrics and peer evaluations in a numerical methods course, providing valuable insights for educators and researchers. The effectiveness of these strategies is evaluated by comparing student engagement levels in this course to those in other courses. Results indicate that for many students these strategies fostered active participation, reduced anxiety, and enhanced overall learning experiences, offering valuable insights into improving student engagement in challenging academic contexts
Young Professionals
No full textLike many of us, I have attended numerous panels, seminars, and workshops geared toward helping young professionals and students. The more senior professionals are gathered for us to question and tap them for wisdom and anecdotes. One such question that inevitably comes up in one form or another is, “How did you get to where you are?” A thinly veiled question intending to ask how can one get to the same or similar position. The response often begins with a soft chuckle and a “well … ” Their answers are caveated by “my path was not the typical path.
Analyzing the Portrayal of the Atomic Bombs Dropped on Hiroshima and Nagasaki in Textbooks and Non-Profit Curriculum Sources
No full textSome veteran history teachers I have met over the years have explained that early in their careers they were encouraged to teach from the textbook. One teacher indicated this has been the dominant mode of teaching for the large portion of her career (J. Baker, personal communication, July 11, 2023). This can be problematic if textbooks do not contain multiple perspectives of events. Keith Crawford and Stuart Foster (2007) write that nations often do not tell the full truth about themselves. U.S. History curriculum is often missing a complete and accurate representation of historical events (Anyon, 1979). Textbooks often support dominant cultural views and promote nationalist metanarratives (Anyon, 1979; Camicia 2007; Loewen 1996). This could stem in large part from the desire of politicians to portray history in a way that strengthens national identity (Grever & Van der Vlies, 2017). One consequence of nationalist history curriculum is that it may not guide individuals to seek the betterment of their country which can lessen improvement in the future (Loewen, 1996). In a democratic society, education is essential, especially education in which students analyze multiple points of view. The real safeguard of democracy is education (Lo & Geiger, 2018). In this study I am comparing perspectives in curriculum concerning the atomic bombs the United States dropped on Japan in World War II. The focus will be on textbooks and non-profit curriculum makers
Increased Positive Tree Species Mixture Effects on the Abundance and Richness of Collembola With Stand Development in Canadian Boreal Forests
No full textIt is well established that species mixtures could enhance ecosystem functioning in diverse ecosystem types, with these benefits increasing over time. However, the impact of tree mixtures on Collembola communities following stand development in natural forests remains unclear, despite the critical roles Collembola plays in litter decomposition and nutrient cycling. We investigated the effects of tree species mixtures on Collembola abundance, diversity, and community structure by sampling pure and mixed jack pine (Pinus banksiana Lamb.) and trembling aspen (Populus tremuloides Michx.) of 15-year-old and 41-year-old stands in natural boreal forest. In total, 6,620 individuals of Collembola were identified as belonging to 39 species/morphospecies. Our results showed significant effects of stand types on Collembola with higher abundance and richness in conifer and mixed stands than in broadleaf stands. Additionally, with stand development, we observed increased Collembola abundance and richness. In 15-year-old stands, Collembola abundance, richness, and evenness in mixed-species stands were comparable to those in single-species stands. However, as stands developed, tree mixture effects became more pronounced, resulting in higher Collembola abundance and richness in mixed-species stands compared to the average of single-species stands in 41-year-old stands. Further, we observed positive associations between the mixture effects on Collembola abundance and richness with soil nutrient contents. We conclude that tree species mixtures can significantly enhance Collembola abundance and diversity, particularly in older stands and those with elevated soil nutrient levels
Chia Seed Gel Powder as a Clean-Label Enhancer of Texture, Physicochemical Quality, Antioxidant Activity, And Prebiotic Function in Probiotic Low-Fat Yogurt
No full textThis study evaluated the effect of incorporating chia seed gel powder (CSGP) as a natural, clean-label stabilizer on the physicochemical, functional, microbiological, microstructural, antioxidant, and sensory properties of probiotic low-fat yogurt (PLFY) during 21 days of refrigerated storage. Six formulations were prepared using 0–2.5% CSGP, including Control (0% CSGP), YOG1 (0.5% CSGP), YOG2 (1.0% CSGP), YOG3 (1.5% CSGP), YOG4 (2.0% CSGP), and YOG5 (2.5% CSGP). Results showed that increasing CSGP levels noticeably enhanced the total solids, protein content, viscosity, hardness, and water-holding capacity of the PLFY (p \u3c 0.05), while consistently reducing syneresis. Antioxidant activity also rose with higher CSGP concentrations, with YOG5 exhibiting the greatest DPPH scavenging activity (35.12%). Confocal laser scanning microscopy revealed a denser and more uniform protein network in PLFY fortified with CSGP, consistent with rheological measurements showing increased storage (G′) and loss (G″) moduli. Probiotic viability significantly increased (p \u3c 0.05) in CSGP-added samples, indicating a potential prebiotic effect of CSGP. Sensory results demonstrated that although higher CSGP levels slightly darkened the yogurt color, body, texture, flavor, and total sensory scores improved markedly, with YOG5 gaining the highest total score (81.77). The results demonstrate that CSGP acts as a highly effective, multifunctional ingredient that enhances texture, stability, probiotic viability, and antioxidant capacity, making it a strong clean-label candidate for developing high-quality, functional probiotic low-fat yogurt
Characterization and Calibration of Single-Mode Fiber-Coupled Laser Diodes as Irradiance Sources for Astronomical Observatories
No full textCurrent problems in astrophysics relating to the determination of stellar properties, properties of exoplanet host stars, and observation of the expanding universe due to dark energy depend on accurate measurements of flux (a.k.a. spectral irradiance) from stellar sources. Flux calibrations of observatories are typically based on natural standard stars that currently have tenuous SI traceability where additional uncertainty occurs from differences in the reference source and target observations during the scale transfer measurements. CANDLE (Calibration using an Artificial star with NIST-traceable Distribution of Luminous Energy), is a prototype instrument payload to demonstrate an artificial light source that could be flown in space and enable flux calibrations of ground or space observatories with uncertainty less than 0.5% (k=1) across the visible to near-infrared spectral range from 350 nm to 2000 nm with rigorous SI traceability.
CANDLE will reduce the uncertainty of stellar flux measurements by providing an on-orbit source of calibrated spectral irradiance. The instrument consists of three illumination modes that will be SI-traceable to the NIST primary optical watt radiometer (POWR) through physical standards that are available on-orbit. One mode will consist of a set of mirrors that direct sunlight to a target observatory and which is traceable through solar irradiance measurements by other space-based instruments. A second mode will consist of a broadband monochromator and the third mode will consist of a set of single-mode fiber-coupled laser diodes at discrete wavelengths spanning the spectral range and falling within target observatory band-pass filters. In these latter two cases, SI traceability will be provided by on-board reference standard detectors (an electrical substitution radiometer and set of photodiodes) that carry the flux responsivity scale to orbit. These on-orbit reference sources will better mimic target star observations and help reduce systematic effects by cross-checks available from the three illumination modes.
This talk concerns the single-mode fiber-coupled laser illumination mode of CANDLE. It will detail current progress towards the fiber-optical design, understanding of the estimated flux level, and target observatory calibration and uncertainty budget. It will also detail progress made towards radiometric testing of a single-mode fiber-coupled laser diode calibrated irradiance source and efforts towards improving the technology readiness level of the laser illumination mode. This presentation will show that the chosen lasers can survive vibration, vacuum, and radiation testing and that measurements of the irradiance from a single-mode fiber laser can be made at the 0.1% stability level, which is a target for achieving observatory response calibrations with total uncertainty less than the 0.5% level (k=1)
Inter-sensor Level 1 radiometric performance assessment using Deep Convective Clouds Method: Application to Sentinel-2 and Landsat 8 and 9
No full textThe European Union (EU) created the Copernicus programme to achieve a global, high quality Earth observation capacity. The eyes of this programme are the Sentinel missions, and among them the Sentinel-2 mission provides high-resolution optical imaging in thirteen different bands, from visible to short-wave infrared. The Deep Convective Clouds (DCC) method is used to monitor inter-satellite level 1 radiometry in the framework of the Optical Mission Performance Cluster, an EU-funded Copernicus programme managed by the European Space Agency to assess the performance of optical missions. Sentinel-2 instruments MSI-A, B and C are monitored with this method along with Landsat OLI and OLI-2 instruments. Recent improvements in the methodology enabled an extension of the monitoring in the SWIR bands, up to 2200 nm, by computing spectral band adjustment factors (SBAF). These SBAF have been computed using hyperspectral DCC observations from the EnMAP mission. Results of this method show a good stability of the sensors, and relative differences of reflectance between MSI-A and B lower than 1% for all bands analysed, similarly for the relative difference between OLI and OLI-2, and relative difference between MSI units and OLI and OLI-2 lower than 3% for all bands analysed. The methodology will be presented in detail along with significant results. Consolidated results regarding the validation of MSI-C, especially during the tandem phase, will also be discussed
World Average Intercomparison Method: An Approach to Compare Landsat 8 OLI to Landsat 9 OLI
No full textComparative observations between two or more sensors viewing the same target(s) of known or stable radiance close in time have been successfully used for decades to calibrate and cross-compare calibration of various sensors. While the common target approach has proven effective in ensuring data consistency, they typically involve coordinating near-simultaneous data acquisition that are resource-intensive. The need to address geometric, spectral, atmospheric, and angular differences between measurements adds further complexity, making these methods challenging to implement on a routine basis. This study uses an approach to evaluate radiometric scales of two sensors using statistics of their global coverage of the Earth surface as the common target. Hence, it is agnostic to time, site, atmospheric condition, or angle considerations. We demonstrate feasibility of that concept by assessing the level of agreement between Landsat 8 and Landsat 9 reflectance data using two variations of the approach, namely the Data Average and the World Average methods. The primary goal is to evaluate the consistency of the reflectance measurements from the two satellite datasets across 16-day periods. We use metrics such as the ratio of as-observed reflectance values and Earth Mover’s Distance (EMD) to evaluate differences between the two datasets and describe how to mitigate the risk of potential oversampling when comparing global data. Results of the World Average and Data Average methods are consistent with the previous Landsat 8 and Landsat 9 underfly studies, underscoring excellent agreement between the radiometric scale of the sensors onboard the two platforms