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Design of Precast Post-tensioned Slabs using Lightweight Concrete for Residential Foundations
Get PDFThe use of precast concrete in construction is highly favored due to its many benefits, including improved quality control, reduced construction time, increased durability, and sustainability. In Oklahoma, post-tensioned slabs are commonly utilized in construction projects due to their resilience and capacity to withstand expansive soil movement. Nevertheless, when it comes to residential foundations, precast post-tensioned concrete slabs may present some limitations, such as challenges related to their
transportation and installation due to their weight.
The use of lightweight concrete (LWC) for precast slabs and structural elements has become increasingly popular due to its lower concrete density resulting from the use of lightweight aggregates. This not only makes transportation and installation more manageable but also enhances insulation. However, the use of lightweight concrete may result in reduced tension and shear strength, which could be addressed by incorporating post-tensioning. This research was conducted to identify the key factor in designing and producing a precast post-tensioned slab using LWC. The goal was to create a slab that can be manufactured off-site, transported to the job site, and positioned using a crane for lifting and a leveling mechanism for attachment to the foundation on site. This study consisted of four phases; the first phase involved reviewing previous research conducted on precast post-tensioned slabs made with LWC. In the second phase, a LWC mix was developed that could be used for the precast post-tensioned slabs cast in this project. The third phase focused on designing the slab using various methods and software. Finally, in the fourth and last phase of the research project tests were carried out on medium and large-scale specimens of the slab design developed in Phase 3, using the mix developed in Phase 2.
Valuable insights were gained from the research study results. First, it was confirmed that the final mix design developed during the study was feasible, performed as intended, and yielded positive results. Secondly, it was noted that while design software can be used to design structural elements, it is important to double-check reinforcement details for the sake of construction. Third, a preliminary design for precast post-tensioned slabs was carried out, and the medium specimen responded as expected without showing any cracks or excessive deflections, indicating the feasibility of this structural element. Finally, inadequate rigging led to inconclusive results for the large-scale specimen
AN EVIDENCED-BASED CURRICULUM FOR CLINICAL REASONING EDUCATION IN NOVICE STAGE LEARNERS: A NEUROLOGY STROKE CURRICULUM FOR PRECLINICAL PHYSICIAN ASSISTANT EDUCATION
Get PDFIntroduction
Preventable medical error represents a top 10 cause of mortality in the United States and misdiagnosis is the most common, costly and dangerous form of medical error. An estimated 80,000 people die every year because of misdiagnosis related harms. Although various approaches to the problem of misdiagnosis have been explored, research and expert consensus suggest that educational interventions are most likely to improve the problem of misdiagnosis. Specifically, improved educational models in clinical reasoning are thought to be the most effective approach to improving diagnostic capacity among healthcare teams. The majority of data and research on the problem of misdiagnosis focuses on physician performance. Other healthcare providers, like physician assistants, play a significant role in the modern healthcare system but less is known about the diagnostic performance of physician assistants. Although existing data suggest that physician assistants, like their physician counterparts, may be associated with diagnostic error, there is virtually no mention of diagnostic performance or preventable medical error in the literature.
Methods
Working from the premise that physician assistants would benefit from improvements in clinical reasoning training, the study set out to design a curriculum in diagnostic proficiency. Using the literature on best practices and evidence-based principles, an experimental curriculum in diagnostic proficiency was developed and delivered at a Midwestern physician assistant training program. The experimental curriculum focused on neurology with an emphasis on diagnosis of stroke. The rationale for this content emphasis is that neurology represents a significant source of misdiagnosis with stroke being a frequent cause of misdiagnosis related harm. The form of the study was a within-subjects comparison between trainee performance on material covered by the experimental curriculum (neurology, stroke) versus trainee performance on content covered by the institution’s conventional curricula. The effect of the experimental curriculum on the diagnostic capacity of the trainees was measured using case studies and illness script exercises. The study compared the trainee's performance on conditions covered by the experimental curriculum (anterior stroke and posterior stroke) against conditions covered by the institution’s existing curriculum (Henoch-Schönlein purpura and acute adrenal insufficiency). Additionally, student attitudes toward the curriculum of diagnostic proficiency were assessed using a series of survey questions.
Results
Trainee performance on the conditions covered by the experimental curriculum demonstrated a diagnostic accuracy of 88% (posterior circulation stroke case study) and 62% illness script repleteness (cardiogenic anterior stroke). Trainee performance on conditions not covered by the experimental curriculum (taught using the institutions current practices) demonstrated a diagnostic accuracy of 46% (Henoch-Schönlein purpura case study) and an illness script repleteness of 16% (acute adrenal crisis). Student attitudes toward the experimental curriculum were positive with qualitative analysis showing favorable student comments correlating with the evidence-based principles of the experimental curriculum
Roots of colonialism in Old English poetry
Get PDFThe white nationalist ideologies that drove many colonialist efforts are often built off of a so-called Anglo-Saxon ideal, which involves appealing to Old English epics such as Beowulf as part of the foundation of national and racial origins. However, beyond the problematic associations with white supremacy, such postures towards Old English texts and Germanic culture of the era read race anachronistically into the past and ignore the actual cultural contexts these Old English texts are rooted in. Thus, the goal of this thesis project is to analyze Old English texts through a postcolonial lens, informed by Rambaran-Olm, Hsy, Miyashiro, Kim, and Ahmed. I also bring in the central concept of "Christendom" as defined by Harris and Mittman. Using close reading and comparative translation, I evaluate the Old English poems Genesis A & B, Judith, and Andreas through this postcolonial framework. In Chapter One, I analyze Genesis A & B, which calls attention to the importance of land to the migratory Germanic tribes, to inherited righteousness or wickedness through family lines, and to Christendom's efforts to connect the promise of Abraham to the Christians of the day. Chapter Two covers Judith, which focuses on how leadership is an important factor in the classification of humankind as righteous or wicked and on how these distinctions factor into future destination. Judith, with its positive depictions of Jews and Christian additions, also points to the idea of supersessionism. In Chapter Three, I address Andreas, which complicates the dichotomy of righteousness and wickedness by showing the righteous as flawed and the wicked as capable of transformation. As a conversion story featuring the salvation of an "uncivilized" group (the Mermedonians), there are also protocolonialist ideas that justify mass converting Indigenous and other non-Christian people groups. Taken all together, the themes in these three poems support my initial thesis that protocolonialist ideas are present in these texts, which provides deeper understanding of how nationalist and colonialist ideologies evolved over history and led to the rise of present-day white nationalism. My research is part of a growing trend of medieval literary scholarship: applying a postcolonial approach to tracing the roots of white nationalism. Christendom's classification of humankind, as demonstrated in these three poems as a division of the righteous and the wicked, also gives a frame to apply to other Old English texts. Specifically, the other biblically-inspired texts of the Junius Manuscript, Old English hagiographies like Elene, and epics that follow the apostles such as The Fate of the Apostles would be natural opportunities to explore further consistencies or challenges to these ideas
Incarceration as Carceral System Space of Native Racialized (In)Equality: Comparing Sentencing Outcomes Between Native and White People Incarcerated in US Federal and State Prisons
Get PDFOverincarceration of Indigenous peoples across North America is a critical and deep-rooted social issue. Racialized structural inequality are theorized to underpin racialized inequalities in carceral system outcomes including sentence length, monetary penalties, and supervision. Settler colonialism is theorized to underpin these inequalities per Native people. Taking structural settler colonialism for granted and applying the intertwined frameworks of carceral capitalism and necrocapitalism, my research answers three interrelated questions: How do economic precarity and Native visibility influence racialized differences in: 1) sentence length, 2) the likelihood of being assessed legal financial obligations in addition to incarceration, and 3) the likelihood of expecting post-release supervision? My research relies primarily on data from the Bureau of Justice Statistics Survey of Prisoners. My research utilizes linear regression to examine the outcome of sentence length and binary logistic regression to examine the outcomes of the likelihood of fines or fees and expecting supervision, applying the same models to two separate subsamples for the Native and white incarcerated people surveyed. My research findings indicate a limited influence per Native visibility and no influence per individual-level economic precarity on the outcomes for the Native subsample. Though individual-level measures of economic precarity did have some influence on the outcomes for the white subsample. Further, the group-level measures of white economic precarity influenced these outcomes across subsamples and Native economic precarity had a limited influence for both subsamples. My research contributes to the literatures examining both racialized carceral system inequality and Native structural inequalities by investigating patterns of inequality across states, demonstrating at least limited applicability of critical theories of carceral system inequalities to Native experiences, and, most significantly, illuminating directions that future research in the area of Native racialized carceral system inequalities must take to unpack this complex structural issue
Characterization of Cas proteins for enhanced genome applications and antibacterials
No full textCRISPR-Cas systems provide adaptive immunity to bacteria and archaea. They do this by a CRISPR RNA (crRNA)-led Cas nuclease. The Cas protein recognizes the invader genome based on signature motifs present only in the invader [for example a 2-8 nucleotides long DNA motif called the protospacer adjacent motif (PAM)], followed by complementary base pairing between crRNA and the invader genome forming an “R-loop”. The R-loop formation triggers the nuclease activity of the Cas protein, effectively neutralizing the invasion. Recently mechanisms of Cas9 and Cas12a nucleases have been used to develop gene therapies and molecular diagnostics tools. Cas9 is the most-used gene editing tool at present, but Cas12a has favorable features for in vivo gene editing because of its smaller size, crRNA processing ability, and creation of staggered double-stranded DNA (dsDNA) cleavage post editing that enhances recombination events. Gene editing with these Cas proteins, however, has some setbacks. Even though complementarity between the crRNA and target DNA is necessary for dsDNA cleavage to occur, some mismatches between them are tolerated and lead to off-target cleavage. Cas9 and Cas12a have also been shown to cleave or degrade DNA non-specifically in the absence of a crRNA (RNA-independent, R-I) or after being activated of crRNA-dependent DNA cleavage (called as trans activity). All these non-specific activities (off-target, RNA-independent, and trans cleavages) can cause unwarranted genome changes following the use of Cas proteins in genome applications. To increase its safety and to promote it as a mainstream gene editing tool, we focused on removing off-target cleavage of Cas12a and screen for decreases in non-specific activities such as R-I and trans DNA cleavage activities. We used protein engineering of a conserved arginine-rich “bridge helix” of Cas12a that was shown to play an integral role in mediating conformational changes of Cas12a needed for DNA cleavage and to impart specificity in DNA cleavage. We also assess the role of Cas9 protein in alternate functions such as promoting bacterial virulence. We used a bioinformatics-based protein sequence analysis to identify motif(s) in the Cas9 sequence that are uniquely present only in pathogenic bacteria. These studies combined will enhance our knowledge of CRISPR-Cas systems that will lead to safer gene editing tools and expand the CRISPR toolbox to include novel antibiotic targets
Driving Mechanisms of Very Rapid Sea Ice Loss Events
Get PDFForecasting Arctic sea ice is a complex, open problem in polar science, exasperated by climate change and Arctic amplification. Climate models consistently under represent sea ice processes on subseasonal timescales which may contribute to the forecasting challenges. Very rapid sea ice loss events (VRILEs) are substantial sea ice loss events that occur on the timescale of days. There are three mechanisms proposed to cause VRILEs: heat transport by surface cyclones, wind driven ocean waves, and ocean heating from vertical mixing. We hypothesize that ocean waves play as much if not more of a role in causing VRILEs as atmospheric heat transport.
We approach this problem from three perspectives. First, a detailed comparison of sea ice properties in observations and the Community Earth System Model version two large ensemble (CESM2 LENS). Of note is that neither CESM2 or any other model couples ocean waves to sea ice. We find that model performance in this area is insufficient to study short term phenomena meaningfully. Next we take a statistical approach, utilizing multivariate EOFs to examine the relative importance of various atmospheric and ocean fields to subseasonal changes in sea ice concentration. In general, heating terms more strongly co-vary with sea ice concentration than ocean waves with seasonal difference in the importance of 2-m temperature anomalies. Finally we construct a one-dimensional, Finite Element Analysis model to study how effective ocean waves are at fracturing sea ice in the Marginal Ice Zone (MIZ). Ocean waves, particularly low frequency waves, are capable of fracturing large ice floes over a kilometer deep in the MIZ. Taken all together, we find that ocean waves likely play an causal role for VRILEs but one intertwined with the other mechanisms. That is, there is not a single most important factor but VRILEs are related to increased storminess caused by a surface cyclone interacting with a preexisting high pressure system that generated ocean waves and upwelling. They cyclone itself transports heat, especially in its warm sector, and its winds can drive sea ice both deeper into the central Arctic and out of the Arctic depending on the cyclone's local winds
The Invisible Artist: The Editor's Perspective on Rhetoric, Ethics, and Representation in Film Editing
No full textThis dissertation explores the impact that the film editor has on films and what their beliefs are when it comes to the content that they create. Examining history, this dissertation shows that film editors have always impacted movies and the story that is shown. Historically film editors have been overlooked, with only a handful of editors, such as Walter Murch, being known amongst film viewers. Very few editors talk about what they do in the editing room and instead, when conversing focus on the story of the film. This dissertation is a qualitative study that interviewed narrative film editors, those that edit fictional films. The study attempted to interpret (1) what editors understand about their editing; (2) what editors think they are doing to the audience; (3) whether an accurate representation of ethnicities and minorities were ever a consideration; and (4) whether the ethics of their own edits are ever a consideration during the editing process. This dissertation attempted to understand what methods narrative film editors use and to what extent these editors understand the rhetorical aspects of editing, and attempted to understand to what extent these film editors recognize the way these editing methods affect their film viewers. Nine editors were interviewed. Among many other things, it was found that the editor always considers the audience of the film, while at the same time the editor believes they are not responsible for any ethical considerations and that these considerations is a job for someone else. At the same time, the editors’ identity determined if representation was a factor in the way they edited
Examining the Characteristics and Evolution of Temperature Whiplash Events in the US Southern Plains
Get PDFRapid extreme temperature swings, termed “temperature whiplashes”, can lead to significant and intense socioeconomic impacts. Few studies have considered tem- perature whiplashes over global, continental, or other large domains. These analyses suggest that certain locations within the domain may experience greater temperature swings, one being the United States Southern Plains. By selecting a specific area and considering temperature whiplashes on a regional scale, skillful, long-lead prediction of and adaptation for these events may be improved. This study focuses on defining and characterizing temperature whiplash events in the Southern Plains region of the United States, specifically during the winter months (December-February). Two types of whiplashes are defined: the hot-to-cold and cold-to-hot. Using the European Centre for Medium-Range Weather Forecasts’ Fifth Reanalysis (ERA5) from 1950-2023, the Temperature Swing Index is calculated and area-averaged across the Southern Plains. Days where the Temperature Swing Index exceeds the 90th percentile are termed “high swing days” (HSD). Temperature whiplash events are selected by examining each HSD, and considering the longevity and persistence of the overall temperature trend and the signs of the temperature anomalies up to 4 days before and after the HSD. This defi- nition yields 45 anomalously hot-to-cold whiplash events and 14 cold-to-hot whiplash events. Trends of the HSDs and whiplash events reveal increases in frequency since the 1990s. Composites of the geopotential height field at multiple pressure levels and lags illustrate large-scale atmospheric evolutions and key features, like atmospheric blocking or amplified wave trains, that could enhance long range prediction. Addition- ally, stratospheric-tropospheric interactions such as wave reflection are identified as a possible precursor to these events. By establishing the characteristics of temperature whiplash events and their precursors, there is the opportunity to improve predictions of these extreme events and determine how they may change in a changing climate
Folding Proteins In-Silco
Get PDFDetermination of how proteins transform into their biologically relevant structure is an extraordinarily complex research area. They fold into their native state as a population of conformations on time scales that experimental methods struggle to resolve. Molecular dynamic simulations can avoid some of these issues, pro- viding theoretical answers to protein dynamics. To that effect, this work presents two enhanced sampling methods that aim to lower the computational cost of the Replica Exchange protocol with fewer replicas while avoiding the exchange bot- tleneck in an approach called Replica-Exchange-with-Tunneling. The method is used to simulate the folding switch of the metamorphic chemokine Lymphotactin. Go-model potentials bias replicas to fold as either the Ltn10 form or Ltn40 form. This study proposes that the conversion between the two forms is assisted by bi- furcated hydrogen bonding. Resolution-Exchange-with-Tunneling (ResET) builds further on these advancements by reducing the number of replicas to the minimum of 2, while still avoiding exchange rejection and enhancing sampling. The folding performance of the method is shown to outperform other simulation approaches for folding the trpcage protein. It was also used to elicit the contribution that amino acid mutations have on the behavior of Alzheimer associated amyloid beta proteins