Open Research Oklahoma (Oklahoma State Univ.)
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On combinatorics of the Arthur trace formula, convex polytopes, and toric varieties
No full textWe explicate the combinatorial/geometric ingredients of Arthur’s proof of the convergence and polynomiality, in a truncation parameter, of his noninvariant trace formula. Starting with a fan in a real, finite dimensional, vector space and a collection of functions, one for each cone in the fan, we introduce a combinatorial truncated function with respect to a polytope normal to the fan and prove the analogues of Arthur’s results on the convergence and polynomiality of the integral of this truncated function over the vector space. The convergence statements clarify the important role of certain combinatorial subsets that appear in Arthur’s work and provide a crucial partition that amounts to a so-called nearest face partition. The polynomiality statements can be thought of as far reaching extensions of the Ehrhart polynomial. Our proof of polynomiality relies on the Lawrence–Varchenko conical decomposition and readily implies an extension of the well-known combinatorial lemma of Langlands. The Khovanskii–Pukhlikov virtual polytopes are an important ingredient here. Finally, we give some geometric interpretations of our combinatorial truncation on toric varieties as a measure and a Lefschetz number.Mathematic
“A veneer of progress”: Examining the experiences of Black college graduates in a hyperlocal gap year program
No full textThis case study aimed to examine the experiences of Black college graduates who completed a hyperlocal gap year program in Tulsa, Oklahoma. Much of the literature presented about gap years often occurs between high school and college, when students take an intentional break before pursuing a college degree (GYA, 2020; O’Shea, 2013; Simpson, 2004). However, this study specifically looks at the gap year from college to career, and more specifically for Black college graduates. Without a disruption to the status quo, gap year programs will not only continue to ignore the richness of talent and multiplicity of perspectives that Black graduates offer; but moreover, the status quo will also continue to reinforce systemic racism, exclusion, and widen socioeconomic disparities. The research question that guides this study is: What are the experiences of Black college graduates in a hyperlocal gap year program in Tulsa, Oklahoma during 2020 and 2021? Given the hyperlocal focus of the program, this study seeks to not only understand their perception of Tulsa but examine how living in Tulsa affected their experience. The findings of this study are consistent with the literature on gap year benefits and CRT. For example, the findings suggest gap year programs helped participants develop professionally and personally. However, the findings of this study also yielded results that amplify the nuanced and intersecting factors that shape people's experiences in a city. As researchers, practitioners, and policymakers increase their understanding of how race, racism, and other forms of oppression contribute to belonging and mattering
Effects of nitrogen and the combination of trinexapac-ethyl, paclobutrazol, and flurprimidol on creeping bentgrass putting greens
No full textGolf course putting greens are evaluated based on aesthetic qualities and playability. Cultural practices such as nitrogen (N) fertility and the use of plant growth regulators (PGRs) can influence both quality and the visual aesthetic of a putting green surface. The objectives of this research were to assess the effects of 1) N rate and the combination of trinexapac-ethyl, paclobutrazol, and flurprimidol on the playability and turfgrass quality of creeping bentgrass (Agrostis stolonifera cv ‘777’), and 2) N rate and the combination of trinexapac-ethyl, paclobutrazol, and flurprimidol on the severity of the disease commonly referred to as dollar spot, caused by the fungus (Clarireedia jacksonii) on a research putting green in north-central Oklahoma. Nitrogen application treatments included five rates (0, 4.9, 9.8, 14.7, 19.5 kg ha⁻¹ N per application) arranged in factorial with three rates of (0.9, 1.3, 1.6 L ha⁻¹ per application) a mixture of trinexapac-ethyl (1.4%), paclobutrazol (5.6%), and flurprimidol (5.6%). Applications were made every 14 days for 20 weeks starting 1st May 2021 and 2022. Golf ball roll distance (BRD) was measured using a Stimpmeter at 7 and 14 days after each N and PGR application. Visual turfgrass quality (TQ) ratings, normalized difference vegetation index (NDVI), normalized difference red edge (NDRE), and dark green color index (DGCI) were measured weekly to quantify aesthetic quality. Visual dollar spot disease incidence and digital image analysis (DIA) were used to assess dollar spot disease severity. For TQ, NDVI, and NDRE the N treated plots had higher ratings than the non-fertilized plots. Plots receiving PGR had significantly lower NDVI than the non-regulated plots. In 2021, the 0 and 4.9 kg ha⁻¹ N plots resulted in greater BRD than the other three N rates, while a similar pattern was found in 2022. The use of PGR did not influence BRD in 2021, but the highest rate increased BRD in 2022. In 2021, the high N rate (19.5 kg ha⁻¹ N) reduced disease incidence, while in 2022 plots receiving N had reduced disease compared the 0 N rate. Visual disease was also decreased by PGR applications. For each year, average dollar spot size and diameter were decreased by using the high N rate (19.5 kg ha⁻¹ N). Plots treated with PGR had less dollar spot disease than the non-regulated plots. Increasing N resulted in lower BRD but improved turfgrass quality. Both increasing N rates and the use of PGR decreased dollar spot severity and increased turfgrass quality
Resonant dynamics of strongly interacting SU(n) fermionic atoms in a synthetic flux ladder
No full textWe theoretically study the dynamics of n-level spin-orbit coupled alkaline-earth fermionic atoms with SU(n) symmetric interactions. We consider three-dimensional lattices with tunneling along one dimen- sion, and the internal levels treated as a synthetic dimension, realizing an n-leg flux ladder. Laser driving is used to couple the internal levels and to induce an effective magnetic flux through the ladder. We focus on the dense and strongly interacting regime, where in the absence of flux the system behaves as a Mott insulator with suppressed motional dynamics. At integer and fractional ratios of the laser Rabi frequency to the onsite interactions, the system exhibits resonant features in the dynamics. These resonances occur when interactions help overcome kinetic constraints upon the tunneling of atoms, thus enabling motion. Different resonances allow for the development of complex chiral current patterns. The resonances resemble those appearing in the longitudinal Hall resistance when the magnetic field is varied. We characterize the dynamics by studying the system’s long-time relaxation behavior as a function of flux, number of internal levels n, and interaction strength. We observe a series of nontrivial prethermal plateaus caused by the emergence of resonant processes at successive orders in perturbation theory. We discuss protocols to observe the predicted phenomena under current experimental conditions.Physic
Damage detection in bridge girders using machine learning algorithms
No full textModern structural health monitoring (SHM) systems with various types of sensors have been employed to monitor the performance of bridges throughout their service life. In recent years, the use of Machine Learning (ML) techniques has gained momentum due to their versatility and potency for performance prediction, condition assessment, and damage detection. This paper quantifies the efficacy of unsupervised ML algorithms for global damage identification in bridge superstructure. In particular, SOM-PCA and KNN-GA-DBSCAN algorithms are chosen due to their superior performance in classification, pattern recognition, and anomaly detection problems. The two techniques are implemented on data obtained from two large-scale laboratory experimentations performed on a prestressed concrete girder and a steel girder. The girders were subjected to progressive cases of damage to assess the ability of the algorithms in detecting the damage and assessing its degree. Both algorithms were able to detect the presence of damage in the tested specimens. The SOM-PCA approach could also identify the degree of damage severity; however, it required data-dependent model optimization. The KNN-GA-DBSCAN, on the other hand, could automatically estimate the optimal algorithm parameters resulting in an adaptable damage detection process that does not require iterative model optimization. The paper also presents recommendations to adopt the two ML algorithms for damage detection based on the application scenarios
Effects of age on the corticospinal tract’s contribution to gross vs. fine motor control
No full textAs humans age, increasing difficulty in the performance of manual tasks, particularly tasks that require fine, dexterous control of the fingers is typically observed. The causes of these difficulties are numerous, but one source includes a decrease in function of the nervous system. This study sought to measure differential changes in descending motor tracts with transcranial magnetic stimulation. Thirty-three participants, aged 19-79 years, completed this study. Participants were in age groups 18-35, or 65+ years. Participants performed two different manual tasks including precision grip and power grip with their dominant hand. These grips are believed to be preferentially controlled by different descending tracts. During the tasks, transcranial magnetic stimulation was delivered to the hand area of participants’ motor cortex, contralateral to their dominant hand. The response to stimulation was recorded with surface electromyography which was stored for later processing and analysis. Electromyography was recorded from the first dorsal interosseous and abductor pollicis brevis muscles while each participant performed the tasks at 15% and 50% of the electromyographic signal recorded during a maximal voluntary contraction. Transcranial magnetic stimulation measures of motor evoked potential size, motor evoked potential latency, peripheral motor conduction time, and central motor conduction time were used for comparisons. The results of this study indicate that there are age-related changes in TMS measures, but no interaction between age, hand task, and intensity of contraction. These results suggest that differential changes in descending tract function cannot be detected with the methods employed in this study
Drought effects on the efficacy of physical removal management to reduce the growth of an invasive species
No full textIncreasing drought and temperatures associated with climate change have enhanced the expansion of some invasive plant species. However, drought impacts on the efficacy of invasion control, e.g., physical removal management such as clipping or mowing, are largely unknown. Thus, we conducted a greenhouse experiment to assess the growth of the invasive grass Sorghum halepense (Johnsongrass) maintained under drought, clipping, or a combination of drought and clipping, compared to plants maintained under sufficient water without physical removal. We measured above- and belowground biomass and eco-physiological parameters related to plant water status and arbuscular mycorrhizal (AM) fungi related factors. We found that: (1) Clipping efficacy, indicated by the difference in aboveground biomass between clipped and non-clipped grass, was significantly less under drought than non-drought; (2) The reduced efficacy was likely related to changes plant water stress suggested by leaf transpiration and water potential; (3) The reduced efficacy might not be driven by AM fungal abundances and leaf phosphorus. Overall, the reduced clipping efficacy under drought could be driven by the lower water stress of clipped plants than corresponding non-clipped ones, resulting in greater transpiration to improve carbon and nitrogen uptake via stoma and root, respectively. Given the drought impacts, implementation of physical removal management via clipping should consider the specific climate and weather conditions of a site
Comparison of adverse event reporting between adolescent and young adults and older adults with cancer enrolled in Phase II/III clinical trials
No full textBackground: Momentum to improve cancer outcomes in adolescents and young adults (AYAs, diagnosed between 15-39 years of age) has been growing in recent years. However, there remains to be significant barriers to understanding differences in treatment response in AYAs compared with younger and older patients. Currently, it is unknown the extent to which AYA adverse event data is reported separately in oncology clinical trials that enroll AYAs and older adults. For this reason, this study investigates not only the reporting of disaggregated AYA clinical trial data in published oncology trials, but also the differences in treatment-related adverse events experienced by AYAs.Methods: In our cross sectional analysis, we performed a comprehensive search using PubMed (which includes Medline) to identify all clinical trials that met eligibility criteria published from January 1, 2021 to December 31, 2021. Two independent investigators title and abstract screened, full-text screened, and extracted data from the final study sample using Google Forms. In addition to obtaining demographic data for each included trial, a further assessment was made to see if the trial distinguished outcomes between AYAs and older adults. Microsoft Excel was used for summary data and measures of central tendency. No further statistical analyses were planned.Results: A total of 572 Phase II and Phase III cancer trials evaluating anti-cancer agent(s) or radiation interventions in either breast, colorectal, Hodgkin’slymphoma, non-Hodgkin’s lymphoma, or melanoma met the inclusion criteria. Of these included trials, zero (0/572, 0.00%) disaggregated adverse event AYA clinical trial data.Conclusion: There remains a substantial gap in understanding the adverse event profile regarding anticancer agent(s) or radiation interventions in the AYA population with either breast, colorectal, Hodgkin’s lymphoma, non-Hodgkin’s lymphoma, or melanoma. We recommend future clinical trials evaluate and disaggregate AYA adverse event clinical trial data from other age groups to assess the differences in treatment-related adverse events in AYAs and to improve guidelines and treatment protocols for AYA patients with cancer
Life cycle of intermittent streams: How do fish communities respond to annual cycles of wetting and drying?
No full textIntermittent streams are widespread systems that exhibit regular patterns of drying, but the patterns of drying between geographically close streams are not fully understood. We evaluated the patterns of flow across a year in ten intermittent streams within a single drainage basin in southeastern Oklahoma, with hopes of comparing patterns of drying between each stream and describing variation between streams using readily calculatable flow metrics. At each site we installed stream intermittency sensors and evaluated stage height using low-cost methods. We evaluated landscape levels factors as potential drivers of flow patterns. Intermittent streams varied based on both high and low flow metrics, while being driven by a variety of landscape level factors, with the strongest correlations resulting from variations in watershed size. Additionally, we compared the observed flow regimes within our system with an established flow model, finding that modeled streamflow patterns generally underrepresented drying present within the system. Although intermittent streams periodically cease to flow, they still provide habitat and refugia for aquatic species that inhabit them. Community dynamics within intermittent streams are driven by a wide range of factors, including drying regime, existence of refugia, and connectivity with perennial systems. We examined fish community dynamics in ten intermittent streams over the course of a drying and rewetting period in order to determine the differences in fish community composition and recovery trajectories across a gradient of drying regimes. Seasonal shifts in community composition were highly variable between systems, with only the smallest and largest streams exhibiting similar patterns. However, fish communities exhibited quick recovery post drying across all drying regimes, and significant variation in community composition during the drying period. The role of intermittent streams serving as seasonal refugia, and the inherent variation between systems, reflects the importance of conservation of flow regimes and the role that drying plays in constructing aquatic communities
Reggio Emilia Approach in the United States
No full textProgressive educational approaches are growing in interest in the United States. The Reggio Emilia Approach is one progressive philosophy that is gaining traction in the realm of early childhood education. Due to the approach's contextual nature and value placed on children and teachers, it could have benefits for the increasingly diverse population in the United States. Additional research is needed on the approach overall, particularly on its utilization in the context of the United States. Utilizing a survey with both open-ended and closed-ended questions, this study attempted to better understand what educators are using from the approach, their perceptions of the approach, and how the approach has impacted their practice and/or philosophy. This study found that educators are able to utilize a variety of Reggio-inspired aspects and have been impacted positively, but there was a very limited understanding of the approach and its philosophical foundations. This can inform future researchers, Reggio-inspired professional development, and Reggio-inspired teacher preparation programs to ensure a quality understanding of the approach and its philosophical foundations. This can also inform any educators who are interested in researching the approach themselves to focus on the philosophical foundations before the specific practices but also to inform that it is possible to be Reggio-inspired in any context in the United States