Open Research Oklahoma (Oklahoma State Univ.)
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Synthesis and characterization of tri-/bidentate imidazolium-based ocn/oco ligands and their copper(i) and palladium(ii) complexes
No full textThe coordination chemistry of N-heterocyclic carbenes (NHCs) and their applications in various fields, including catalysis, have earned considerable interest over the past few decades. Among the different classes of NHC ligands, pincer-type systems are particularly significant due to their potential for chelate formation and ease of electronic and steric modifications. This research project focused on the synthesis and characterization of novel tridentate NHC ligands with different derivatives of phenol and quinoline as wingtips. These ligands were designed to stabilize both precious and earth-abundant transition metals with different oxidation states, including Cu(I) and Pd(II).
The synthesized Cu(I) complexes of the I-(2,4-ᵗBuPh,2-Q).HBr ligand were characterized using single crystal X-ray diffraction, which revealed their binuclear nature with a Cu-Cu bond length indicating a strong cuprophilic interaction attributed to the C, N, and O coordinating sites and the complex's symmetrical geometry, which was further improved by using different Cu sources. The single crystal X-ray structure of the Cu(I) complex with the same ligand but Cu(II) source showed a binuclear bridged Cu(I) complex, where two ligands coordinated to two bridged Br atoms through the carbene carbon and quinoline nitrogen. Additionally, the Pd(II) complex of the same ligand exhibited an intriguing crystal structure with two different complexes co-crystallized in a unit cell.
The research also involved the synthesis of diverse NCO ligands featuring an ether as well as a quinoline or pyridine as wingtips to imidazole, and their coordination chemistry to Pd(II) and Cu(I). In this set of ligands, complexes formed mononuclear complexes where two ligands coordinated through the carbene carbon and quinoline/pyridine nitrogen as bidentate ligands, rather than through the ether oxygen
Racial disparities in emergency department wait times for patients presenting with chest pain and shortness of breath: An analysis of the National Hospital Ambulatory Medical Care Survey (NHAMCS) 2019-2021
No full textIntroduction: Extended Emergency Department (ED) wait times are associated with adverse health outcomes, including insufficient treatment rates, admissions, and mortality, especially in patients with chest pain and dyspnea. Given people of racial/ethnic minorities disproportionately experience health disparities, identifying barriers to care in the ED may impact already vulnerable populations, thus improving health equity. Therefore, our primary objective was to assess differences in ED wait times by race for patients presenting with chest pain and dyspnea using the National Hospital Ambulatory Medical Care Survey (NHAMCS) data.Methods: Using survey weights provided by NHAMCS, we determined national estimates for ED wait times for 2019-2021 by ED triage level for patients presenting with chest pain and dyspnea. We constructed a linear regression to assess the difference in wait times by race/ethnicity. We applied bootstrapping (2000 replications) to account for unbalanced samples between racial/ethnic groupings and controlled for race, sex, age, triage level, and urbanicity.Results: All racial/ethnic minority groups experienced longer wait times than White patients except for Other/Multiracial. In our linear regression analysis, Black patients (34.66 minutes; SE = 2.95 ) experienced a statistically significant increase in ED wait times compared to White patients (28.09 minutes; SE = 1), according to the binary model.Conclusion: Our study demonstrates that racial disparities in the ED persist, given the increased wait times for minority patients. Racial disparities in the ED are complex; therefore, expanding research to identify strategies to further mitigate contributing factors are crucial to reaching health equity
On the structure of non-degenerate holomorphic mappings
No full textIn this thesis, we study a few salient aspects of non-degenerate holomorphic mappings and discuss a rigidity phenomenon of proper holomorphic mappings. Proper holomorphic mappings are central objects of investigation in the fields of several complex variables, and various geometric and topological properties of them are subjects of active research. We consider three such unrelated questions in this thesis.
Chapter II consists of the study of the local topology of singular non-degenerate holomorphic mappings ⨍ : Ω ⊂ ℂ^n ⟶ ℂ^(n+1). The main contribution is extending a result of Lyubich-Peters [53] for general singular complex analytic curves in ℂ^2. We also provide a different proof of another result of Lyubich-Peters regarding associating Riemann orbifolds with complex analytic curve singularities.
We study the asymptotic geometry of conformally compact and asymptotically hyperbolic (AH) manifolds in Chapter III. We show that in general non-AH conformally compact cases the geodesics possess logarithmic singularities in the tangential direction of their velocities, and use this to extend a previous result of Mazzeo [58].
In Chapter III, we classify proper holomorphic mappings from ball complements and ball differences inside the complex Euclidean space. We discover that every nicely behaved proper map of ball complements are polynomial proper map of balls. Moreover, we show that every rational sphere map that maps sufficiently many concentric spheres to concentric spheres can be expressed to be unitarily equivalent to direct sums of homogeneous polynomials
Teaching in adversity: How Oklahoma teachers navigate instruction on race, gender, and sexuality
No full textConservative lawmakers are increasingly passing legislation that would ban the teaching of race, gender, and sexuality within K-12 schools. Because these bills impact both teachers and students, it is important to understand how teachers perceive, and potentially resist, these bills. Building on prior conceptualizations of occupational activism and inequality frames, the author develops a typology to examine how and why some K-12 teachers resist, comply, or support anti-DEI legislation. In interviews with 45 Oklahoma K-12 public school teachers, the author finds that a challenging social and political climate led some teachers to remove or avoid discussions of diverse topics, even though they believed these topics were important to discuss with students. What led some teachers to continue teaching about these topics despite a contentious political and social environment? The author found that teacher identity and student demographics were reasons why teachers continued to teach about these topics, and engagement in community organizing efforts led some respondents to redefine teaching as a form of activism. Finally, some teachers supported anti-DEI legislation because they believed that teachers should not discuss topics of race, gender, and sexuality with their students. These perceptions were guided by a belief that the education system was engulfed in a culture war, and that parents should be the ones to have these conversations with students. Findings from this research underscore the importance of identity and cultural context in understanding how teachers perceive their role in the classroom
Ocean Motion: Motion table
No full textLawrence Livermore National Laboratory has a six degree of freedom motion platform that they want to use for drone testing. Mainly testing drone take-off and landing from an unsteady platform like the motion of a boat dock on the ocean, so they do not have to test their drone in the actual ocean. My team and I were tasked with creating a one degree of freedom motion platform to enhance the vertical motion of their 6 DOF platform. The planform receives ocean input data to mimic the larger amplitude lower frequency ocean movement
Is flight experience a causal factor in preventable general aviation LOC-I accidents
No full textThe general aviation (GA) sector in the United States is losing pilots at an alarming rate each year due to a phenomenon known as loss of control in flight (LOC-I). This issue has plagued aviation since its inception and is now the leading cause of GA accidents in the U.S. While exceeding the angle of attack (AOA) explains how a pilot may lose control of their aircraft in flight, the underlying reasons why pilots find themselves vulnerable to this anomaly remain unclear. This quantitative causal-comparative research study aimed to determine if inexperienced GA pilots with fewer than 300 hours of flight time are more susceptible to LOC-I than those with more than 300 hours. Data for this study were gathered by querying the National Transportation Safety Board’s (NTSB) archival accident database CAROL (Case Analysis and Reporting Online) to identify GA LOC-I accidents occurring from January 1, 2010, to December 31, 2019. The findings from the ten-year data analysis reveal that LOC-I was the leading cause of accidents and fatalities in GA, accounting for one accident every two days and one fatal accident every four days. The results from this study also showed a significant decrease in LOC-I accidents as pilots accumulated additional flight time. Utilizing Microsoft Excel’s© Frequency function on the final dataset of 1,465 LOC-I accidents showed that pilots with less than 300 flight hours were involved in 404 LOC-I accidents, while pilots who logged between 1,200 to 1,500 hours were involved in 86 LOC-I accidents. According to the literature, there seems to be a consensus among key industry experts that some novice pilots are not adequately prepared to handle upset conditions due to a lack of understanding of AOA, while more experienced pilots may fall victim to LOC-I situations because of complacency or a lack of proficiency. The overall findings of this research suggest that industry regulators should consider the opinions of experts advocating for mandatory changes in loss of control training and the integration of AOA indicator technology in the cockpit to mitigate a threat that has taken one too many lives
Oklahoma farm and ranch employment handbook
No full textThe Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
Effects of respiratory vaccine delivery method (subcutaneous or intranasal) and timing of initial processing on receiving calf health and performance
No full textThis experiment evaluated the impacts of modified live virus (MLV) respiratory vaccine delivery method and initial processing time in high-risk crossbred calves (n = 662; steers = 336; bulls = 326; initial body weight; BW = 250 ± 11.2 kg) sourced from Oklahoma auction markets. Upon arrival, calves were stratified by arrival sex, blocked by BW, and assigned to 1 of 6 experimental treatment combinations in a 3 × 2 factorial design. Treatment combinations included: processing at 0-d, 2-d, or 14-d with either intranasal (IN) or subcutaneous (SQ) respiratory vaccine delivery. There were differences in final BW (P < 0.01), with the 0-d processing group having the greatest BW, followed by the 2-d and then 14-d groups. There was a processing time by vaccine interaction (P = 0.05) for overall average daily gain (ADG), where ADG generally decreased as processing time increased, however, the 2-dSQ treatment was comparable to both 0-d treatments, and the 14-dIN was similar to 2-dIN. From d 15 to 28 and 29 to 56 the 0-d processing group had or tended to have the greatest ADG (P ≤ 0.07). Dry matter intake (DMI) varied by processing time, with both the 0-d and 2-d groups having greater DMI than the 14-d group from d 15 to 28, 29 to 56, and overall (P < 0.0001, P = 0.04, and P = 0.01, respectfully). Vaccine delivery method also influenced DMI, with IN having greater DMI from d 1 to 14 and 15 to 28 (P ≤ 0.03). Overall, the 0-d group had superior gain:feed (G:F) compared to both other processing day treatments (P < 0.01). Time to initial processing increased days to first bovine respiratory disease (BRD) treatment (P < 0.01), with the 14-d group being treated the latest. Second and third antimicrobial treatments for BRD were reduced or tended to be reduced for the 0-d group compared to the 14-d group (P ≤ 0.07). There was a processing time by vaccine interaction for infectious bovine rhinotracheitis (IBR)-specific antibody titers where the 0-dIN group had the highest titers on d 56 (P ≤ 0.05)
From startup to stability in rural counties: An assessment of support organizations’ impact on small business creation and maturation
No full textA significant amount of research has demonstrated the importance of entrepreneurship for economic and community development in rural areas. Less established is what type of local support organizations can foster the birth and growth of these small businesses. Another unanswered question is whether the relationship between business outcomes and support organizations is similar between rural and urban locations.
We test the general hypothesis that more local support organizations leads to higher business births and maturation (i.e. growing to a "Stage 2" business of 10+ employees) using panel data for all U.S. counties from 2015-2023. The dependent variables are aggregate 2-digit NAICS births for each county-year, and the independent variables of interest are 5 distinct 4-digit NAICS categories including religious organizations, grantmaking / giving services, social advocacy organizations, civic and social organizations, and business / professional organizations. The data comes from the Business Dynamics Research Consortium at Wisconsin and is compiled from Data Axle (which follows millions of U.S. businesses over time).
Fixed effect panel Poisson models estimate the impact of the 5 distinct support organizations on births and maturation. These models include county and year fixed effects and control for the number of businesses started (in the same sector and overall) in the prior year as well as education, income, unemployment, and broadband adoption rates. The results show that some support organizations (grantmaking services, civic organizations) have positive impacts while others (religious, social advocacy) are typically negative. There are meaningful differences in results across metro, non-metro and "very rural" counties