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Title: Regulation of Chlamydomonas reinhardtii cell cycle during synchronous growth
Creator: Lin, Yang-Tsung
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The regulation of the cell cycle in microalgae has long been a central topic in third-generation biofuel studies, as it relates to biomass accumulation and lipid production, the two determining factors of economically feasible biofuel production. The discovery of Compromised Hydrolysis of TAG 7 (CHT7) in the green alga Chlamydomonas reinhardtii has provided valuable insights into the metabolic status-dependent regulation of the cell cycle. CHT7 belongs to the CHC protein family, members of...
Show moreThe regulation of the cell cycle in microalgae has long been a central topic in third-generation biofuel studies, as it relates to biomass accumulation and lipid production, the two determining factors of economically feasible biofuel production. The discovery of Compromised Hydrolysis of TAG 7 (CHT7) in the green alga Chlamydomonas reinhardtii has provided valuable insights into the metabolic status-dependent regulation of the cell cycle. CHT7 belongs to the CHC protein family, members of which include transcriptional regulators programming the initiation of cell division. A similar role of CHT7 in mediating cell cycle progression has been suggested. However, the regulatory mechanism and specific processes regulated by CHT7 have yet to be determined. In this dissertation, I applied bioinformatics approaches to comprehensively study CHT7-mediated gene regulation during the cell cycle using cell cultures synchronously grown in bioreactors. I found that specific pathways such as DNA replication, chromosome condensation, and spindle assembly are affected by the absence of CHT7. Other affected pathways include cell-wall remodeling and previously uncharacterized putative kinase cascades. In addition, I discovered the presence of two potential cis-regulatory elements near the transcription start site of misregulated genes in cht7, which are potentially linked to homeodomain transcription factors. Moreover, I explored the potential relationship between the CHT7-mediated pathway and the gene network governed by the retinoblastoma protein complex. Lastly, I characterized the function of a novel CHC protein in cell cycle progression and compared it with the role of CHT7. Together, these studies facilitate a better understanding of the cell cycle regulation in microalgae.
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Title: Advancements in Applied Behavior Analysis Service Delivery, Supervision, and Feedback
Creator: Thomas, Emma
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Supervision is critical to the field of Applied Behavior Analysis (ABA) because it improves the quality of services provided to the recipients of behavioral services which in turn increases client protection and helps to portray the field of ABA as one that is committed to socially significant behavior change (Britton & Cicoria, 2019; Brodhead & Higbee, 2012; Hartley et al., 2016; LeBlanc & Luiselli, 2016; LeBlanc et al., 2020; Turner et al., 2016). Without effective supervision, the quality...
Show moreSupervision is critical to the field of Applied Behavior Analysis (ABA) because it improves the quality of services provided to the recipients of behavioral services which in turn increases client protection and helps to portray the field of ABA as one that is committed to socially significant behavior change (Britton & Cicoria, 2019; Brodhead & Higbee, 2012; Hartley et al., 2016; LeBlanc & Luiselli, 2016; LeBlanc et al., 2020; Turner et al., 2016). Without effective supervision, the quality of services may decrease and negatively impact treatment outcomes for the clients (Britton & Cicoria, 2019; Dixon et al., 2016; Eikeseth, 2009; LeBlanc & Luiselli, 2016; Shapiro & Kazemi, 2017). Given the rapid growth of the field of ABA, supervision will continue to play a critical role in training, fostering the growth and development of professionals and ensuring those professionals uphold the high standards of the profession (Hajiaghamohseni et al., 2020; Turner et al., 2016; Turner, 2017). The current dissertation addressed and evaluated supervision of behavior analytic services provided to individuals with autism spectrum disorder (ASD) in three different contexts: (1) supervision provided during the implementation of behavioral interventions, (2) supervision provided via Telehealth, specifically evaluating barriers and strategies used to address and/or mitigate those barriers, and (3) supervision provided via Telehealth in the form of email performance-based feedback. Collectively, these chapters sought to address gaps in the current behavior analytic supervision literature and identify additional areas of study. Chapter 1 provides an overall introduction connecting the three separate, but related chapters (Chapters 2-4) and includes a supervision logic model. Chapter 2 is a systematic literature review that evaluated the extent to which recently published articles included information regarding supervision and staff training of the individuals implementing behavioral interventions to young children with ASD. The results of Chapter 2 revealed that there is little to no consensus on reporting supervision and staff training characteristics in the current behavioral intervention literature. Research implications and reporting recommendations will be discussed. Chapter 3 is a survey study that evaluated the barriers Board Certified Behavior Analysts (BCBAs) experienced and the strategies BCBAs used to address and/or mitigate the barriers that arose when providing supervision via Telehealth. The results of Chapter 3 revealed that BCBAs that provide supervision via Telehealth are not exempt from experiencing barriers. Research and practical implications will be discussed. Chapter 4 is a single case research design study that evaluated the extent to which email performance-based feedback increased procedural fidelity of teacher candidates’ implementation of a multiple stimulus without replacement (MSWO) preference assessment. The results revealed that email performance-based feedback was effective in increasing procedural fidelity of MSWO preference assessment implementation. These results support previous literature suggesting that email performance-based feedback alone is effective in increasing target behavior(s). Research implications will be discussed. Finally, Chapter 5 provides an overall discussion about the findings of the three chapters (Chapters 2-4), recommendations for research and practice, and considerations for the future direction of supervision in the field of ABA.
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Title: DISCOURSES OF WELL-BEING OF ADOLESCENT GIRLS LIVING IN PATAGONIA, CHILE
Creator: Bilbao Nieva, Maria Isidora
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The term well-being entails material and subjective elements, and it is critical to promote it during adolescence. Access to opportunities and resources are key determinants to well-being, but not all adolescents have the same living conditions. In the specific case of adolescent girls living in Latin American countries, structural barriers to well-being are derived from gender and cultural factors that influence their everyday experiences. From a Community Psychology perspective, structural...
Show moreThe term well-being entails material and subjective elements, and it is critical to promote it during adolescence. Access to opportunities and resources are key determinants to well-being, but not all adolescents have the same living conditions. In the specific case of adolescent girls living in Latin American countries, structural barriers to well-being are derived from gender and cultural factors that influence their everyday experiences. From a Community Psychology perspective, structural factors are critical to well-being promotion and should be considered alongside individual-level factors.Using Feminist Critical Discourse Analysis, this study examined the discourses of well-being of ten adolescent girls from low-income families living in Coyhaique. The analysis was focused on how girls talk about what contributes to their well-being, with a specific focus on structural conditions that affect them. The results showed that while they spoke of individual-level factors contributing to their well-being, they also mentioned structural issues influenced by gender and culture. Those structural level factors were related to resources, support networks, and community environment. Implications for well-being promotion are discussed.
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Title: Variational Bayes inference of Ising models and their applications
Creator: Kim, Minwoo
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Ising models originated in statistical physics have been widely used in modeling spatialdata and computer vision problems. However, statistical inference of this model and its application to many practical fields remain challenging due to intractable nature of the normalizing constant in the likelihood. This dissertation consists of two main themes, (1) parameter estimation of Ising model and (2) structured variable selection based on the Ising model using variational Bayes (VB).In Chapter 1,...
Show moreIsing models originated in statistical physics have been widely used in modeling spatialdata and computer vision problems. However, statistical inference of this model and its application to many practical fields remain challenging due to intractable nature of the normalizing constant in the likelihood. This dissertation consists of two main themes, (1) parameter estimation of Ising model and (2) structured variable selection based on the Ising model using variational Bayes (VB).In Chapter 1, we review the background, research questions and development of Isingmodel, variational Bayes, and other statistical concepts. An Ising model basically deal with a binary random vector in which each component is dependent on its neighbors. There exist various versions of Ising model depending on parameterization and neighboring structure. In Chapter 2, with two-parameter Ising model, we describe a novel procedure for the pa- rameter estimation based on VB which is computationally efficient and accurate compared to existing methods. Traditional pseudo maximum likelihood estimate (PMLE) can pro- vide accurate results only for smaller number of neighbors. A Bayesian approach based on Markov chain Monte Carlo (MCMC) performs better even with a large number of neighbors. Computational costs of MCMC, however, are quite expensive in terms of time. Accordingly, we propose a VB method with two variational families, mean-field (MF) Gaussian family and bivariate normal (BN) family. Extensive simulation studies validate the efficacy of the families. Using our VB methods, computing times are remarkably decreased without dete- rioration in performance accuracy, or in some scenarios we get much more accurate output. In addition, we demonstrates theoretical properties of the proposed VB method under MF family. The main theoretical contribution of our work lies in establishing the consistency of the variational posterior for the Ising model with the true likelihood replaced by the pseudo- likelihood. Under certain conditions, we first derive the rates at which the true posterior based on the pseudo-likelihood concentrates around the εn- shrinking neighborhoods of the true parameters. With a suitable bound on the Kullback-Leibler distance between the true and the variational posterior, we next establish the rate of contraction for the variational pos- terior and demonstrate that the variational posterior also concentrates around εn-shrinking neighborhoods of the true parameter.In Chapter 3, we propose a Bayesian variable selection technique for a regression setupin which the regression coefficients hold structural dependency. We employ spike and slab priors on the regression coefficients as follows: (i) In order to capture the intrinsic structure, we first consider Ising prior on latent binary variables. If a latent variable takes one, the corresponding regression coefficient is active, otherwise, it is inactive. (ii) Employing spike and slab prior, we put Gaussian priors (slab) on the active coefficients and inactive coefficients will be zeros with probability one (spike).
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Title: WISDOM FROM A MENTOR IN A MATTER OF MINUTES : INVESTIGATING A PROPOSED MODEL OF FLASH MENTORSHIP IN STUDENT-ALUMNI INTERACTIONS
Creator: Wisner, Amy Marie
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Mentoring is an age-old practice that proves meaningful for protégés across contexts and program designs. Because both mentoring practice and mentoring research take place in a wide variety of domains and with seemingly limitless program details, it has become difficult to define or execute with any precision. Mentoring practitioners and researchers would benefit greatly from a mentorship model to inform their program designs and selection of mentoring type best-suited to the situation. In...
Show moreMentoring is an age-old practice that proves meaningful for protégés across contexts and program designs. Because both mentoring practice and mentoring research take place in a wide variety of domains and with seemingly limitless program details, it has become difficult to define or execute with any precision. Mentoring practitioners and researchers would benefit greatly from a mentorship model to inform their program designs and selection of mentoring type best-suited to the situation. In recent years, a type of mentoring that has gained popularity is flash mentorship. This short-term, one-time interaction is desirable because of the limited commitment required for everyone involved. However, little is known about the effectiveness of this type of mentorship. The current work sought to develop a model of effective flash mentorship with the broader goal of establishing best practices for pairing mentors with protégés in meaningful ways. A proposed model of flash mentorship posited that relationship quality and advice quality predicted protégé situational satisfaction. Antecedents of relationship quality were posited to include attraction and deep-level similarity. Antecedents of advice quality were posited to include message features and mentor expertise. Although all causal links posited by the model were of sufficient magnitude to be consistent with predictions, the fit of the model proved insufficient. Limitations of the findings and recommendations for future research are discussed.
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Title: DESIGN AND ENGINEERING OF STARCH-BASED POLYMER MATERIALS AS SUBSTITUTES FOR PERSISTENT NON-BIODEGRADABLE PLASTICS
Creator: Kulkarni, Apoorva Chandrakant
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Replacing carbon-carbon backbone persistent hydrocarbon plastics with biobased and biodegradable plastics offers value proposition of reduced carbon footprint and an environmentally responsible end-of-life. This work focuses on design and engineering of starch based polymeric materials as substitutes for non-biodegradable plastics. The biodegradability of these bioplastics in aqueous environment was evaluated.Starch foams are being used as replacement for petroleum-based foams in insulation...
Show moreReplacing carbon-carbon backbone persistent hydrocarbon plastics with biobased and biodegradable plastics offers value proposition of reduced carbon footprint and an environmentally responsible end-of-life. This work focuses on design and engineering of starch based polymeric materials as substitutes for non-biodegradable plastics. The biodegradability of these bioplastics in aqueous environment was evaluated.Starch foams are being used as replacement for petroleum-based foams in insulation and cushion protection applications. However, moisture sensitivity remains a problem resulting in collapse of cell structure and loss of mechanical integrity. First section of the thesis focuses on engineering high-performance starch foams with enhanced moisture resistance using reactive extrusion processing technology. Chitosan, polyvinyl butyral (PVB) and sodium trimetaphosphate (STMP) were used with water as a plasticizer and a blowing agent to make foams with desired physico-mechanical properties. The resulting foams were hydrophobic, insoluble in water, and showed improved moisture resistance. The biodegradability of the foams was not impacted – they were completely biodegradable as established by ASTM/ISO standards. Crosslinking of starch with STMP increased the compressive strength of the foams by three times compared to control foams. Optimization of process parameters ensured an efficient, cost-effective route towards commercialization. In the second section, our group’s chemically modified thermoplastic starch (MTPS) prepared by reactive extrusion technology was explored in three different applications. First, MTPS, was melt blended with glycol modified polyethylene terephthalate (PETG) using transesterification chemistry to synthesize MTPS-g-PETG in situ graft copolymer with 33% grafting. Mechanical and thermal properties of the blend were evaluated and compared with neat PETG. The addition of starch into PETG molecular backbone did not result in PETG biodegradability. This finding refutes many claims of biodegradability of non-biodegradable polymers by the addition of starch and similar additives. in the marketplace. Second, the use of MTPS as a biobased and biodegradable nucleating agent and barrier property enhancer in polylactide (PLA) was explored. Our findings establish that MTPS accelerates the rate of crystallization of PLA (polylactide polymers) by up to 98 times at 100°C, reducing the half time for crystallization from 20 mins to less than 1 minute. Oxygen barrier properties of PLA was improved 127% without causing detrimental impact on mechanical properties or biodegradability. Third application focuses on using MTPS as a carrier for iodine, which is a very effective and strong antimicrobial agent. The antimicrobial starch-iodine complex in pellet form was manufactured by extrusion processing. The new MTPS-iodine complex was incorporated in various proportions to commercial fully biodegradable-compostable polyester films. The morphological, mechanical, and antibacterial properties of these films were evaluated and compared with current commercial additives used to obtain antibacterial properties. The last section focuses on the end-of-life evaluations for biobased and biodegradable plastics using kinetics approach. The effect of temperature on biodegradation of cellulose and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) in an aqueous environment seeded with a biologically aggressive microbial inoculum was studied. A global equation was derived from the reparametrized Arrhenius equation and the kinetic rate law to estimate the time required for 90% removal of polymer from the low temperature ocean environment. The t90 (time required to remove 90% of the polymer carbon from the environment) for PHBV at 10°C ranged from 6.2-6.9 years. The t90 of cellulose at 10 C was found to be 1.1-1.2 years. ASTM/ISO standards for measuring and reporting ocean biodegradability is static and conducted at one temperature (30°C), whereas ocean temperatures can vary from −1.8 °C to 33.4 °C. The kinetic analysis and model developed can provide a method to estimate time for complete removal of the biodegradable polymer carbon in ocean environments.
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Title: Fast and Memory-Efficient Subspace Embeddings for Tensor Data with Applications
Creator: Zare, Ali
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The widespread use of multisensor technology and the emergence of big data sets have brought the necessity to develop more versatile tools to represent higher-order data with multiple aspects and high dimensionality. Data in the form of multidimensional arrays, also referred to as tensors, arise in a variety of applications including chemometrics, physics, hyperspectral imaging, high-resolution videos, neuroimaging, biometrics, and social network analysis. Early multiway data analysis...
Show moreThe widespread use of multisensor technology and the emergence of big data sets have brought the necessity to develop more versatile tools to represent higher-order data with multiple aspects and high dimensionality. Data in the form of multidimensional arrays, also referred to as tensors, arise in a variety of applications including chemometrics, physics, hyperspectral imaging, high-resolution videos, neuroimaging, biometrics, and social network analysis. Early multiway data analysis approaches used to reformat such tensor data as large vectors or matrices and would then resort to dimensionality reduction methods developed for low-dimensional data. However, by vectorizing tensors, the inherent multiway structure of the data and the possible correlation between different dimensions will be lost, in some cases resulting in a degradation in the performance of vector-based methods. Moreover, in many cases, vectorizing tensors leads to vectors with extremely high dimensionality that might render most existing methods computationally impractical. In the case of dimension reduction, the enormous amount of memory needed to store the embedding matrix becomes the main obstacle. This highlights the need for approaches that are applied to tensor data in their multi-dimensional form. To reduce the dimension of an $n_1 \times n_2 \times \dots \times n_d$ tensor to $m_1 \times m_2 \times \dots \times m_d$ with $m_j \leq n_j$, MPCA\footnote{Multilinear Principal Component Analysis} would change the memory requirement from $\prod_{j=1}^d m_jn_j$ for vector PCA to $\sum_{j=1}^d m_jn_j$, which can be a considerable improvement.On the other hand, tensor dimension reduction methods such as MPCA need training samples for the projection matrices to be learned. This makes such methods time consuming and computationally less efficient than oblivious approaches such as the Johnson-Lindenstrauss embedding. The term \textit{oblivious} refers to the fact that one does not need any data samples beforehand to learn the embedding that projects a new data sample onto a lower-dimensional space.\\ In this thesis, first a review of tensor concepts and algebra as well as common tensor decompositions is presented. Next, a modewise JL approach is proposed for compressing tensors without reshaping them into potentially very large vectors. Theoretical guarantees for the norm and inner product approximation errors as well as theoretical bounds on the embedding dimension are presented for data with low CP rank, and the corresponding effects of basis coherence assumptions are addressed. Experiments are performed using various choices of embedding matrices. Results verify the validity of one- and two-stage modewise JL embeddings in preserving the norm of MRI and synthesized data constructed from both coherent and incoherent bases. Two novel applications of the proposed modewise JL method are discussed. (i) Approximate solutions to least squares problems as a computationally efficient way of fitting tensor decompositions: The proposed approach is incorporated as a stage in the fitting procedure, and is tested on relatively low-rank MRI data. Results show improvement in computational complexity at a slight cost in the accuracy of the solution in the Euclidean norm. (ii) Many-Body Perturbation Theory problems involving energy calculations: In large model spaces, the dimension sizes of tensors can grow fast, rendering the direct calculation of perturbative correction terms challenging. The second-order energy correction term as well as the one-body radius correction are formulated and modeled as inner products in such a way that modewise JL can be used to reduce the computational complexity of the calculations. Experiments are performed on data from various nuclei in different model space sizes, and show that in the case of large model spaces, very good compression can be achieved at the price of small errors in the estimated energy values.
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Title: Optimizing and Improving the Fidelity of Reactive, Polarizable Molecular Dynamics Simulations on Modern High Performance Computing Architectures
Creator: O'Hearn, Kurt A.
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Reactive, polarizable molecular dynamics simulations are a crucial tool for the high-fidelity study of large systems with chemical reactions. In support of this, several approaches have been employed with varying degrees of computational cost and physical accuracy. One of the more successful approaches in recent years, the reactive force field (ReaxFF) model, wasdesigned to fill the gap between traditional classical models and quantum mechanical models by incorporating a dynamic bond order...
Show moreReactive, polarizable molecular dynamics simulations are a crucial tool for the high-fidelity study of large systems with chemical reactions. In support of this, several approaches have been employed with varying degrees of computational cost and physical accuracy. One of the more successful approaches in recent years, the reactive force field (ReaxFF) model, wasdesigned to fill the gap between traditional classical models and quantum mechanical models by incorporating a dynamic bond order potential term. When coupling ReaxFF with dynamic global charges models for electrostatics, special considerations are necessary for obtaining highly performant implementations, especially on modern high-performance computing architectures.In this work, we detail the performance optimization of the PuReMD (PuReMD Reactive Molecular Dynamics) software package, an open-source, GPLv3-licensed implementation of ReaxFF coupled with dynamic charge models. We begin byexploring the tuning of the iterative Krylov linear solvers underpinning the global charge models in a shared-memory parallel context using OpenMP, with the explicit goal of minimizing the mean combined preconditioner and solver time. We found that with appropriate solver tuning, significant speedups and scalability improvements were observed. Following these successes, we extend these approaches to the solvers in the distributed-memory MPI implementation of PuReMD, as well as broaden the scope of optimization to other portions of the ReaxFF potential such as the bond order computations. Here again we find that sizable performance gains were achieved for large simulations numbering in the hundreds of thousands of atoms.With these performance improvements in hand, we next change focus to another important use of PuReMD -- the development of ReaxFF force fields for new materials. The high fidelity inherent in ReaxFF simulations for different chemistries oftentimes comes at the expense of a steep learning curve for parameter optimization, due in part to complexities in the high dimensional parameter space and due in part to the necessity of deep domain knowledge of how to adequately control the ReaxFF functional forms. To diagnose and combat these issues, a study was undertaken to optimize parameters for Li-O systems using the OGOLEM genetic algorithms framework coupled with a modified shared-memory version of PuReMD. We found that with careful training set design, sufficient optimization control with tuned genetic algorithms, and improved polarizability through enhanced charge model use, higher accuracy was achieved in simulations involving ductile fracture behavior, a difficult phenomena to hereto model correctly.Finally, we return to performance optimization for the GPU-accelerated distributed-memory PuReMD codebase. Modern supercomputers have recently achieved exascale levels of peak arithmetic rates due in large part to the design decision to incorporate massive numbers of GPUs. In order to take advantage of such computing systems, the MPI+CUDA version of PuReMD was re-designed and benchmarked on modern NVIDIA Tesla GPUs. Performance on-par with or exceeding the LAMMPS Kokkos, a ReaxFF implementation developed at Scandia National Laboratories, with PuReMD typically out-performing LAMMPS Kokkos at larger scales.
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Title: The Impact of Social Class on Students’ Pre-College Perceptions of Co-Curricular Involvement
Creator: Rossman, Danielle
Date: 2022
Collection: Electronic Theses & Dissertations
Description: This dissertation uses a cross sectional quantitative design to investigate the relationship between first-year college students’ social class and their pre-college interest in engaging in co-curricular experiences during college, their motivations for engaging in co-curricular experiences, and their perceptions of whether co-curricular activities will teach them leadership and work ethic skills. The study also investigated multiple variables to address social class- including metrics of...
Show moreThis dissertation uses a cross sectional quantitative design to investigate the relationship between first-year college students’ social class and their pre-college interest in engaging in co-curricular experiences during college, their motivations for engaging in co-curricular experiences, and their perceptions of whether co-curricular activities will teach them leadership and work ethic skills. The study also investigated multiple variables to address social class- including metrics of subjective social status and socioeconomic status. The study used data from two surveys that were administered to a sample (N = 839) of first-year, first-time college students from a regional comprehensive university prior to their matriculation. The findings of this study indicate that students’ awareness of their socioeconomic status was the only significant predictor of their interest in getting involved in co-curricular activities during college. Students’ perceived family contribution to their college education significantly predicted their interest in working during college, while social class had no impact on a student’s interest in joining fraternity and sorority life or in student government association. There was a significant relationship between a student’s race, gender, and high school extracurricular experiences and their motivation for engagement. A student’s Expected Family Contribution was not a significant predictor of the student’s interest, motivation, or perception related to involvement. Students’ awareness of their socioeconomic status also impacted their perceptions that they could learn leadership skills and work ethic from co-curricular activities, while students with higher subjective social class were more likely to believe they could learn leadership skills from being a participant or member in co-curricular experiences. Implications of these findings for research, theory and practice are offered. More research is needed that explores the impact of social class, and incorporates multiple diverse metrics of social class, on students’ college experience. Studies that investigate the ability of on-campus employment to serve as a high impact proactive for students who may not otherwise have the ability to participate in co-curricular experiences on campus are also needed.
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Title: VISIONING THE AGRICULTURE BLOCKCHAIN : THE ROLE AND RISE OF BLOCKCHAIN IN THE COMMERCIAL POULTRY INDUSTRY
Creator: Fennell, Chris
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Blockchain is an emerging technology that is being explored by technologists and industry leaders as a way to revolutionize the agriculture supply chain. The problem is that human and ecological insights are needed to understand the complexities of how blockchain could fulfill these visions. In this work, I assert how the blockchain's promising vision of traceability, immutability and distributed properties presents advancements and challenges to rural farming. This work wrestles with the...
Show moreBlockchain is an emerging technology that is being explored by technologists and industry leaders as a way to revolutionize the agriculture supply chain. The problem is that human and ecological insights are needed to understand the complexities of how blockchain could fulfill these visions. In this work, I assert how the blockchain's promising vision of traceability, immutability and distributed properties presents advancements and challenges to rural farming. This work wrestles with the more subtle ways the blockchain technology would be integrated into the existing infrastructure. Through interviews and participatory design workshops, I talked with an expansive set of stakeholders including Amish farmers, contract growers, senior leadership and field supervisors. This research illuminates that commercial poultry farming is such a complex and diffuse system that any overhaul of its core infrastructure will be difficult to ``roll back'' once blockchain is ``rolled out.'' Through an HCI and sociotechnical system perspective, drawing particular insights from Science and Technology Studies theories of infrastructure and breakdown, this dissertation asserts three main concerns. First, this dissertation uncovers the dominant narratives on the farm around revision and ``roll back'' of blockchain, connecting to theories of version control from computer science. Second, this work uncovers that a core concern of the poultry supply chain is death and I reveal the sociotechnical and material implications for the integration of blockchain. Finally, this dissertation discusses the meaning of ``security’’ for the poultry supply chain in which biosecurity is prioritized over cybersecurity and how blockchain impacts these concerns. Together these findings point to significant implications for designers of blockchain infrastructure and how rural workers will integrate the technology into the supply chain.
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Title: EXPLORING STUDENTS’ UNDERSTANDING OF INTERACTIONS AND ENERGY ACROSS CHEMISTRY AND BIOLOGY
Creator: Noyes, Keenan Chun Hong Lee
Date: 2022
Collection: Electronic Theses & Dissertations
Description: One of the goals of science education is to help students make sense of the world around them. To that end, it is critical that students understand the central ideas in each discipline like, in chemistry, energy and interactions. These ideas are of particular importance because they are directly related to one another and are relevant across other science disciplines. Unfortunately, researchers have found that students often struggle to develop a deep understanding of these ideas. To uncover...
Show moreOne of the goals of science education is to help students make sense of the world around them. To that end, it is critical that students understand the central ideas in each discipline like, in chemistry, energy and interactions. These ideas are of particular importance because they are directly related to one another and are relevant across other science disciplines. Unfortunately, researchers have found that students often struggle to develop a deep understanding of these ideas. To uncover better ways to support students’ learning, I explored how students understand interactions and energy in both chemistry and biology.In this dissertation, I focused on London dispersion forces (LDFs), a type of intermolecular force (IMF) which occurs between all atoms and molecules. Specifically, I used the lens of causal mechanistic reasoning to think about students’ knowledge. That is, how students connect the properties and behaviors of the underlying entities to the overall phenomenon. If we can help students to develop this type of understanding, they may be able to make powerful predictions about new, unfamiliar phenomena in which IMFs play an important role. Additionally, I explored how students thought about the energy changes which result from the formation of LDFs. Lastly, I designed assessments to elicit and characterize explanations of protein-ligand binding, a biological phenomenon governed by IMFs. To explore these questions, I used a mix of qualitative and quantitative techniques. I designed tasks to elicit causal mechanistic responses from students, using students’ responses to refine the task design. I also developed coding schemes to characterize students’ engagement in causal mechanistic reasoning. Furthermore, I developed and used automated resources to analyze thousands of responses in a matter of minutes. In these studies, I focused primarily on undergraduate students enrolled in Chemistry, Life, the Universe, and Everything (CLUE), a transformed, core-idea centered general chemistry curriculum. From these studies, I found that the majority of CLUE students could leverage electrostatic ideas to explain LDFs, and that a meaningful proportion of those students could provide a full causal mechanistic account. This highlights the importance of emphasizing these interactions, and the mechanism by which they form, throughout the general chemistry course sequence. Additionally, students who used causal mechanistic reasoning to discuss LDFs were more likely to use that same reasoning in the context of the associated changes in potential energy. However, this relationship was weaker among those providing a partially causal mechanistic response. This suggests that more work needs to be done to find ways of supporting students to connect the ideas of interactions and energy. Additionally, in this thesis, I describe the process by which I used iterative design to develop a task eliciting causal mechanistic explanations of a biological phenomenon. In future work, these materials can be used to explore how broader groups of students engage with this task in an effort to foster interdisciplinary coherence.
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Title: FATE OF SILVER NANOPARTICLES DURING SIMULATED COMMERCIAL PROCESSING OF FRESH-CUT LETTUCE
Creator: Gunathilaka, Gayathri Upeksha
Date: 2022
Collection: Electronic Theses & Dissertations
Description: ABSTRACTFATE OF SILVER NANOPARTICLES DURING SIMULATED COMMERCIAL PROCESSING OF FRESH-CUT LETTUCEByGayathri Upeksha GunathilakaThe use of silver nanoparticles (Ag NPs) in pesticides could lead to residual levels in food crops, thus raising both food safety and environmental concerns. The effectiveness of typical produce processing practices to remove Ag NPs from fresh produce is poorly understood. Further, little is known about the behavior of Ag NPs in wash water during commercial production...
Show moreABSTRACTFATE OF SILVER NANOPARTICLES DURING SIMULATED COMMERCIAL PROCESSING OF FRESH-CUT LETTUCEByGayathri Upeksha GunathilakaThe use of silver nanoparticles (Ag NPs) in pesticides could lead to residual levels in food crops, thus raising both food safety and environmental concerns. The effectiveness of typical produce processing practices to remove Ag NPs from fresh produce is poorly understood. Further, little is known about the behavior of Ag NPs in wash water during commercial production of fresh-cut produce, which limits our ability to design effective mitigation strategies.The first study evaluated the behavior of Ag NPs over time when exposed to commercially applicable chlorine concentrations (2–100 mg chlorine/L) in simulated lettuce wash water. Aggregation and dissolution of Ag NPs (5 mg/L) were evaluated in the presence and absence of dissolved lettuce extract (DLE, 0.1%). Aggregate size of Ag NPs increased faster in the presence of chlorine (49 to 431 nm) compared to the control (P < 0.05). Lower dissolved Ag concentrations and more negative zeta potentials were found in the presence of chlorine (0.01 to 0.03 mg/L and -39 to -95 mV) and DLE (0.01 to 0.14 mg/L and -28 to -32 mV), as compared to the control (0.54 to 0.8 mg/L and -10 to -20 mV) (P < 0.05). Transmission electron microscopy with energy dispersive spectroscopy confirmed the formation of composite AgCl-Ag NPs particles in the presence of chlorine. The increased aggregate size over time likely resulted from nucleation and crystal growth of AgCl. In the presence of DLE, Ag NPs and AgCl precipitates were embedded in and bound to the DLE matrix. These observations suggest that chlorine and plant-released organic matter could substantially change the fate of Ag NPs in wash water and subsequently their environmental impact. In the second study the removal of Ag NPs from Ag NP-contaminated lettuce leaves was investigated during batch and small-scale pilot processing. First, a batch-type system (4-L carboy jar) was used to evaluate the impact of commercial produce sanitizers and simulated leafy green processing water on the removal of Ag NPs from contaminated lettuce. Peroxyacetic acid (PAA; 80 mg/L) and chlorine (100 mg/L and pH 6.5) were used with/without 2.5% (w/v) organic load as washing treatments with deionized water serving as the control treatment. Treating lettuce with the organic load alone, organic load with chlorine, chlorine alone, 0% organic load and peroxyacetic acid removed about 2.7%–6.6% of Ag from the lettuce after 5 min of washing. Thereafter, the removal of Ag NPs from contaminated lettuce was assessed using a small-scale pilot processing line during 90 seconds of flume-washing followed by centrifugal drying (a typical washing practice in commercial produce processing). The Ag removal efficiency ranged between 0.3% to 3%, probably resulting from strong binding of Ag with plant organic materials. Significantly greater Ag concentrations were found in the centrifugal water than in flume water, suggesting that centrifugation removed additional Ag from lettuce. The low Ag removal observed in both the simulated batch-type and pilot-scale produce washing systems demonstrate that typical produce processing conditions may not be effective in removing Ag NPs from contaminated produce. Thus, it is necessary to further investigate and develop effective methods for the Ag NP removal from contaminated produce.
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Title: A POTENTIAL ROLE FOR EARLY GUT MICROBIAL COLONIZATION IN INFANT BEHAVIOR AND CHILD SLEEP DISORDERS
Creator: Ma, Tengfei
Date: 2022
Collection: Electronic Theses & Dissertations
Description: There is increasing evidence from pre-clinical and human studies implicating the microbiota–gut–brain axis in behavior and sleep physiology. Infancy is a critical time period for brain development and is vulnerable to the harmful effects of gut dysbiosis. Thus, it is crucial to understand how gut microbial colonization during this period may influence behavior and sleep physiology in the later stages of life.We analyzed data from 194 mother-infant pairs from the Michigan Archive for Research...
Show moreThere is increasing evidence from pre-clinical and human studies implicating the microbiota–gut–brain axis in behavior and sleep physiology. Infancy is a critical time period for brain development and is vulnerable to the harmful effects of gut dysbiosis. Thus, it is crucial to understand how gut microbial colonization during this period may influence behavior and sleep physiology in the later stages of life.We analyzed data from 194 mother-infant pairs from the Michigan Archive for Research on Child Health (MARCH) cohort Study. Clinical and demographic information was obtained from the birth certificate and interview during pregnancy and childhood. Fecal samples from infants at 3-9 months of age were sequenced at the V4 region of the 16S rRNA gene. In the first study, which examined whether feeding practices may affect early gut microbial colonization, we found that the gut microbiota of infants who were exclusively breastfed displayed a significantly lower Shannon diversity (p-adjust < 0.001) and a different gut microbiota composition than infants who were not breastfed (p-value = 0.001). Among the exclusively breastfed infants, recipients of supplemental vitamin D displayed a significantly lower Shannon diversity (p-adjust = 0.007) and different gut microbiota composition structure than non-supplemented, breastfed infants (p-value = 0.02). In addition, several individual taxa were identified to be associated with different feeding practices. In the second study, we examined whether gut microbiota in early infancy was associated with temperament in the nine-month-old infants. We identified that a microbial cluster characterized by a higher abundance of Bifidobacterium, Veillonella, and Escherichia-Shigella that was associated with lower emotionality scores (coefficient = -0.58, p-value = 0.02) compared to a cluster characterized by a higher abundance of Bacteroides. This association was especially prominent among infants who were not supplemented with vitamin D (coefficient = -1.01, p-value = 0.01), while no significant association was found among infants who were supplemented (coefficient = -0.43, p-value = 0.20). In the final aim, we assessed the association between gut microbiota in early infancy and the difficulty of initiating and maintaining sleep at age of two years. The gut microbiota of children who had difficulty maintaining sleep displayed significantly higher Shannon index (OR: 2.41, 95% CI= 1.23-4.93, p-adjust < 0.04) and Chao 1 index (OR: 1.01, 95% CI= 1.0-1.03, p-adjust < 0.008) after adjustment for covariates. We also observed that gut microbiota composition was significantly different between children with difficulty initiating (p-value= 0.043) and maintaining sleep (p-value= 0.004) by PERMANOVA based on the unweighted UniFrac distance metric. In conclusion, these results from analysis in a prospective cohort study suggest that early gut microbial colonization is shaped by breastfeeding status, vitamin D supplement, and maternal characteristics including gestational age, delivery mode and education level. Our findings suggested that the infant gut microbiome clusters may be associated with the temperament characteristic of negative emotionality in 9-month-old infants. We also demonstrated a significant association between infant gut microbiome composition and sleep problems in 2-year-old children. Thus, our results add to the evidence that early gut microbial colonization may be linked with brain outcomes with potential long-term effects.
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Title: Quantitative Analysis of New Key Factors of Immune Cells in Autoimmune Diseases
Creator: Bunn, Demarcus
Date: 2022
Collection: Electronic Theses & Dissertations
Description: AbstractExplorations of New Key Factors of Immune Cells in Autoimmune Diseases By Demarcus Bunn The work presented in this dissertation demonstrates an emerging role of immune cells in type one diabetes (T1D) and multiple sclerosis (MS). The immune cells that will be presented are neutrophils and T-cells. Presented work shows an altered cell metabolism in both disease states that leads to further secondary complications. An overview of the immunology, as well as each autoimmune disease, will...
Show moreAbstractExplorations of New Key Factors of Immune Cells in Autoimmune Diseases By Demarcus Bunn The work presented in this dissertation demonstrates an emerging role of immune cells in type one diabetes (T1D) and multiple sclerosis (MS). The immune cells that will be presented are neutrophils and T-cells. Presented work shows an altered cell metabolism in both disease states that leads to further secondary complications. An overview of the immunology, as well as each autoimmune disease, will be presented. Experimental efforts to increase or decrease cell metabolism in order to alleviate secondary complications will be shown. Furthermore, the use of 3D printed devices for in vitro models mimicking these disease states properties will be presented.Individuals T1D have a history of being more susceptible to infection. This section of the dissertation will demonstrate how a once forgotten pancreatic peptide, C-peptide, has a positive effect on raising immunity through improving immune cell energetics. Previous studies in the Spence lab have shown that C-peptide only binds to red blood cells (RBC) in the presence of albumin, but for the biological changes, Zn2+ is needed. Spence lab research has shown that the combination of C-peptide/Zn2+/albumin increases the metabolism of RBCs. This work shows novel data showing that C-peptide binds specifically to other cell types. Additionally, changes in cell metabolism will be investigated. This portion of the dissertation is important for alleviating reoccurring and persistent infections.MS is characterized by the destruction of the myelin sheath around the nerves. The cell type that does the damage is T lymphocytes. However, little research has been done investigating what makes the permeability of the blood-brain barrier increase. Here, we will introduce the potential role of NETosis, a form of programmed cell death, has on blood brain barrier permeability. There have been recent reports that exogenous adenosine triphosphate (ATP) increases the rate of NETosis production in vitro. Previous work in the Spence lab has shown that RBCs from individuals with MS secrete significantly more ATP than control red blood cells. Presented work will show that ATP derived directly from RBCs causes dysregulation of NETosis. The concluding section of the dissertation will be dedicated to 3D printing. An overview of the current state and future advancements of 3D printing will be presented. Presented work will show the use of 3D printing to provide more relevant conditions for in vitro experiments. Here, 3D printed models were used to investigate immune cell behaviors and changes in cell bioenergetics.
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Title: Molecular epidemiology, pangenomic diversity, and comparative genomics of Campylobacter jejuni
Creator: Rodrigues, Jose Alexandre
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Campylobacter jejuni, the leading cause of bacterial gastroenteritis in the United States, is often resistant to commonly used antibiotics and has been classified as a serious threat to public health. Through this work, we sought to evaluate infection trends, quantify resistance frequencies, identify epidemiological factors associated with infection, and use whole-genome sequencing (WGS) as well as comparative phylogenomic and pangenomic approaches to understand circulating C. jejuni...
Show moreCampylobacter jejuni, the leading cause of bacterial gastroenteritis in the United States, is often resistant to commonly used antibiotics and has been classified as a serious threat to public health. Through this work, we sought to evaluate infection trends, quantify resistance frequencies, identify epidemiological factors associated with infection, and use whole-genome sequencing (WGS) as well as comparative phylogenomic and pangenomic approaches to understand circulating C. jejuni populations in Michigan. C. jejuni isolates (n=214) were collected from patients via an active surveillance system at four metropolitan hospitals in Michigan between 2011 and 2014. Among the 214 C. jejuni isolates, 135 (63.1%) were resistant to at least one antibiotic. Resistance was observed for all nine antibiotics tested yielding 11 distinct resistance phenotypes. Tetracycline resistance predominated (n=120; 56.1%) followed by resistance to ciprofloxacin (n= 49; 22.9%), which increased from 15.6% in 2011 to 25.0% in 2014. Notably, patients with ciprofloxacin resistant infections were more likely to report traveling in the past month (Odds Ratio (OR): 3.0; 95% confidence interval (CI): 1.37, 6.68) and international travel (OR: 9.8; 95% CI: 3.69, 26.09). To further characterize these strains, we used WGS to examine the pangenome and investigate the genomic epidemiology of this set of C. jejuni strains recovered from Michigan patients. Among the 214 strains evaluated, 83 unique multilocus sequence types (STs) were identified that were classified as belonging to 19 previously defined clonal complexes (CCs). Core-gene phylogenetic reconstruction based on 615 genes identified three clades, with Clade I comprising six subclades (IA-IF) and predominating (83.2%) among the strains. Because specific cattle-associated STs, such as ST-982, predominated among strains from Michigan patients, we also examined a collection of 72 C. jejuni strains from cattle recovered during an overlapping time period by WGS. Several phylogenetic analyses demonstrated that most cattle strains clustered separately within the phylogeny, but a subset clustered together with human strains. Hence, we used high quality single nucleotide polymorphism (hqSNP) profiling to more comprehensively examine those cattle and human strains that clustered together to evaluate the likelihood of interspecies transmission. Notably, this method distinguished highly related strains and identified clusters comprising strains from both humans and cattle. For instance, 88 SNPs separated a cattle and human strain that were previously classified as ST-8, while the human and cattle derived ST-982 strains differed by >200 SNP differences. These findings demonstrate that highly similar strains were circulating among Michigan patients and cattle during the same time period and highlight the potential for interspecies transmission and diversification within each host. In all, the data presented illustrate that WGS and pangenomic analyses are important tools for enhancing our understanding of the distribution, dissemination, and evolution of specific pathogen populations. Combined with more traditional phenotypic and genotypic approaches, these tools can guide the development of public health prevention and mitigation strategies for C. jejuni and other foodborne pathogens.
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Title: Creating Opportunities for Learning for English Learners with Disabilities Through Quality Individualized Education Programs
Creator: Paul, Jennifer Maria
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Understanding the needs of students who are English learners (ELs) and are also students with disabilities has become an area of policy and research in recent years. Uncovering the needs of this student group requires a closer examination and understanding of the Individualized Education Program (IEP). The IEP is a foundational process and document used by all educators of students identified as students with disabilities to help inform those students’ education. The IEP defines everything...
Show moreUnderstanding the needs of students who are English learners (ELs) and are also students with disabilities has become an area of policy and research in recent years. Uncovering the needs of this student group requires a closer examination and understanding of the Individualized Education Program (IEP). The IEP is a foundational process and document used by all educators of students identified as students with disabilities to help inform those students’ education. The IEP defines everything from a student’s current abilities to their goals and even identifies educators’ plans for instruction and support. The IEP is the ‘road map’ for students’ classroom experiences. But what should be included in the ‘road map’ for students with disabilities that are also ELs? The need to answer this question is of great importance as there is currently no guidance from the Michigan Department of Education for Michigan educators on this topic. It is likely that because of an absence of this magnitude that students would bear the brunt of its absence. The negative repercussions come in the form of a potential lack of students’ learning opportunities specific to their needs as English learners. Through the use of the opportunity to learn (OTL) framework developed by Kurtz and Elliott (2011) my research investigates how educators can improve a student’s OTL within the IEPs they conduct and write. My dissertation explores the barriers educators experience as they develop IEPs for this group of students. It will also consider when educators should include EL’s specific needs within the IEP. The study will also recommend that educators use a tool created through my research to improve OTL for ELs with disabilities within the IEPs on which they work.
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Title: DEVELOPING LIGNIN-BASED EPOXY AND POLYURETHANE RESINS
Creator: Nikafshar, Saeid
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Lignin, the most abundant natural aromatic polymer, is currently produced as by-product during biorefinery and chemical pulping processes. Lignin is rich in hydroxyl functional groups (both phenolic and aliphatic OH), making it an excellent raw material for synthesizing epoxy and polyurethane resins. However, there are several challenges in utilizing unmodified lignins as feedstock for product development, including high polydispersity/heterogeneity, low reactivity, poor accessibility of...
Show moreLignin, the most abundant natural aromatic polymer, is currently produced as by-product during biorefinery and chemical pulping processes. Lignin is rich in hydroxyl functional groups (both phenolic and aliphatic OH), making it an excellent raw material for synthesizing epoxy and polyurethane resins. However, there are several challenges in utilizing unmodified lignins as feedstock for product development, including high polydispersity/heterogeneity, low reactivity, poor accessibility of hydroxyl groups for reaction with co-monomers low solubility in common organic solvents, and dark color. There are significant variations in lignin characteristics, depending on the source of biomass and isolation methods. Therefore, in-depth lignin characterization is needed to provide the basic knowledge of the structural, chemical, and thermal properties to facilitate lignin valorization.This study was focused on lignin characterization and development of lignin-based epoxy and polyurethane resins. First, a wide range of lignin samples was fully characterized by measuring their ash contents, elemental analyses, hydroxyl contents, chemical structures, molar mass distributions, and thermal properties. Next, a novel method was developed to measure the reactivity of thirteen different unmodified lignins toward biobased epichlorohydrin (ECH). A partial least square regression (PLS-R) model (with 92 % fitting accuracy and 90 % prediction ability) was created to study the correlation between lignin properties and epoxy content. The results showed that lignins with higher phenolic hydroxyl contents and lower molecular weights were more suitable for replacing 100 % of toxic bisphenol A (BPA) in the formulation of resin precursors. Additionally, two epoxidized lignin samples (with the highest epoxy contents) were cured using a biobased hardener (Cardolite from cashew nutshell), showed comparable thermomechanical performances and thermal stabilities to a petroleum-based epoxy system. Biobased waterborne polyurethane resins (PUDs) were also developed by entirely replacing the petroleum-based polyol and the internal emulsifier with either alkaline pre-extraction lignins or enzymatic hydrolysis lignins as well as tartaric acid (a biobased diacid). The formulated resins had zero VOC (volatile organic compound), which was achieved by replacing toxic n-methyl-2-pyrrolidone (NMP) with cyrene (a biobased solvent). To further improve the mechanical properties of our biobased PUD resins, 20 wt.% of lignin was substituted with low hydroxyl value soy-polyol, which increased their tensile strength and elongation at break to 87% and 68% of a commercial PUD resin. The results of this study demonstrated that it is imperative to fully characterize lignin and choose the right lignin for each specific application. This approach enabled us to entirely replace petroleum-based raw materials (BPA and polyol) with lignin and formulate biobased epoxy and polyurethane resins.
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Title: Topological Data Analysis and Machine Learning Framework for Studying Time Series and Image Data
Creator: Yesilli, Melih Can
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The recent advancements in signal acquisition and data mining have revealed the importance of data-driven tools for analyzing signals and images. The availability of large and complex data has also highlighted the need for investigative tools that provide autonomy, noise-robustness, and efficiently utilize data collected from different settings but pertaining to the same phenomenon. State-of-the-art approaches include using tools such as Fourier analysis, wavelets, and Empirical Mode...
Show moreThe recent advancements in signal acquisition and data mining have revealed the importance of data-driven tools for analyzing signals and images. The availability of large and complex data has also highlighted the need for investigative tools that provide autonomy, noise-robustness, and efficiently utilize data collected from different settings but pertaining to the same phenomenon. State-of-the-art approaches include using tools such as Fourier analysis, wavelets, and Empirical Mode Decomposition for extracting informative features from the data. These features can then be combined with machine learning for clustering, classification, and inference. However, these tools typically require human intervention for feature extraction, and they are sensitive to the input parameters that the user chooses during the laborious but often necessary manual data pre-processing. Therefore, this dissertation was motivated by the need for automatic, adaptive, and noise-robust methods for efficiently leveraging machine learning for studying images as well as time series of dynamical systems. Specifically, this work investigates three application areas: chatter detection in manufacturing processes, image analysis of manufactured surfaces, and tool wear detection during titanium alloys machining. This work’s novel investigations are enabled by combining machine learning with methods from Topological Data Analysis (TDA), a relatively recent field of applied topology that encompasses a variety of mature tools for quantifying the shape of data. First, this study experimentally shows for the first time that persistent homology (or persistence) from TDA can be used for chatter classification with accuracies that rival existing detection methods. Further, the efficient use of chatter data sets from different sources is formulated and studied as a transfer learning problem using experimental turning and milling vibration signals. Classification results are shown using comparisons between the TDA pipeline developed in this dissertation and prominent methods for chatter detection. Second, this work describes how to utilize TDA tools for extracting descriptive features from simulated samples generated using different Hurst roughness exponents. The efficiency of the feature extraction is tested by classifying the surfaces according to their roughness level. The resulting accuracies show that TDA can outperform several traditional feature extraction approaches in surface texture analysis. Further, as part of this work, adaptive threshold selection algorithms are developed for Discrete Cosine Transform, and Discrete Wavelet Transform to bypass the need for subjective operator input during surface roughness analysis. Both experimental and synthetic data sets are used to test the effectiveness of these two algorithms. This study also discusses a TDA-based framework that can potentially provide a feasible approach for building an automatic surface finish monitoring system.Finally, this work shows that persistence can be used for tool condition monitoring during titanium alloys machining. Since, in these processes, the cutting tools typically fracture catastrophically before the gradual tool wear reaches the maximum tool life criteria, the industry uses very conservative criteria for replacing the tools. An extensive experiment is described for relating wear markers in various sensor signals to the tool condition at different stages of the tool life. This work shows how, in this setting, TDA provides significant advantages in terms of robustness to noise and alleviating the need for an expert user to extract the informative features. The obtained TDA-based features are compared to existing state-of-the-art featurization tools using feature-level data fusion. The temporal location of the most representative tool condition features is also studied in the signals by considering a variety of window lengths preceding tool wear milestones.
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Title: THE ORIGINATION AND IMPLEMENTATION OF THE NATIONAL WETLANDS POLICY OF UGANDA : ENVIRONMENT, KNOWLEDGE, AND POWER FROM THE LATE NINETEENTH CENTURY TO PRESENT
Creator: Doyle-Raso, John
Date: 2022
Collection: Electronic Theses & Dissertations
Description: In the 1980s, following widespread environmental and intellectual changes associated with “swamp reclamation” that in Uganda had started in the early twentieth century, proponents of the emerging science of “wetland conservation” sought to influence the practices and thinking of people across the country. To do so, they created a national wetlands policy based on decentralized “community-based” projects. Yet, farmers’ and investors’ engagements with reclamation have continued. Meanwhile, the...
Show moreIn the 1980s, following widespread environmental and intellectual changes associated with “swamp reclamation” that in Uganda had started in the early twentieth century, proponents of the emerging science of “wetland conservation” sought to influence the practices and thinking of people across the country. To do so, they created a national wetlands policy based on decentralized “community-based” projects. Yet, farmers’ and investors’ engagements with reclamation have continued. Meanwhile, the Ugandan wetlands policy became internationally influential for its groundbreaking approach to interdisciplinary questions about governance, emphasizing economic analyses based on concepts such as “ecosystem services” and “Environmental Economic Valuation.” Ugandan wetland conservationists have had more influence abroad than domestically, as in Uganda neoliberalization and recentralization have limited the power of the community-based groups who have worked through the national policy. Using a range of sources including but not limited to archives and interviews with conservationists, this dissertation historicizes the Ugandan wetlands conservation policy. It comprises two parts addressing overlapping time periods. The first three chapters consider the origination of this policy by analyzing environmental and intellectual changes in southeastern and southwestern Uganda, leading to the creation in the late-twentieth century of environmental regulations. The latter three chapters examine how conservationists have tried implementing the policy in rural and urban places, and in relation to the national emblem of Uganda – the Grey Crowned Crane. They have focused their efforts on community-based projects outside Protected Areas promoting indigenous knowledges and practices to obtain economic benefits from wetlands that conservationists. This approach was an early manifestation of connected trends in international developmentalist networks. Furthermore, the limitations on its implementation have become pivotal in the global histories of neoliberalization, decentralization, and recentralization. Historicizing Ugandan wetland conservationism contributes to four scholarly literatures. 1) Analyzing community-based projects outside “Protected Areas” advances the historiographies of conservation and watershed management in Africa by considering the significances of neoliberalization, decentralization, and recentralization beyond extraordinary legal cases. 2) Examining intellectual changes in this history – including an emphasis on community-based projects, use of the concept of ecosystem services, and the promotion of indigenous knowledges and sciences – reveals connections between changes in environmental science and global trends in developmentalism. 3) Focusing on these changes in Uganda builds on analyses of environmental management in political power there by identifying the importance of an underexamined resource in entrenched land conflicts, and by uncovering early institutional bases of recentralization. 4) Because Ugandan wetland conservationists were global leaders in policy creation, citizen science, and more changes in scientific thinking, researching their work reveals how African scientists have navigated tensions between their local, national, and international interlocutors to become internationally influential. Studying the history of Ugandan wetland conservationism reveals how different people’s engagements with changes in environmental thinking have reshaped environments and livelihoods, as well as influenced international scientific networks.
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Title: QUEER LESSONS IN SUBJECT FORMATION : LEARNING FROM AIDS & SEX
Creator: Travers, Jessica
Date: 2022
Collection: Electronic Theses & Dissertations
Description: My dissertation investigates the formation of the subject. The subject I refer to here is the person, the individual who is shaped by language and discourse, is hailed by interpellation, and is affected by ideological social, cultural, and political forces. I poke and prod at how and why the subject is constructed, and during my analysis of the subject and its formation, I use AIDS literature and art as a lens. While doing so, I discover there is a tight knot around how the subject can define...
Show moreMy dissertation investigates the formation of the subject. The subject I refer to here is the person, the individual who is shaped by language and discourse, is hailed by interpellation, and is affected by ideological social, cultural, and political forces. I poke and prod at how and why the subject is constructed, and during my analysis of the subject and its formation, I use AIDS literature and art as a lens. While doing so, I discover there is a tight knot around how the subject can define and experience itself; thus, I work to loosen that knot, opening more space and air for novel ways the subject is formed—ways that do not encourage conformity, ways that give the subject more agency and creativity in how they become and who they are. Through my analyses and interpretations of works from the AIDS art archive, I uncover queer lessons that confuse, interrupt, and destabilize strict notions of what the subject is, how it is constructed, and how it can express and experience itself. Furthermore, I find that queer and perverted sexualities—erotically-driven desires that exist outside of dominant cultural norms—are an extremely powerful force that destabilizes normative ways that drive and determine how the subject is formed. Ultimately, I argue for a rescripting of how the subject is constructed and offer alternative approaches to subject formations—what I refer to as queer modes of self-authorship. Each of my four chapters narrows in on a queer mode of subject construction: queer interpellation, contact relationality, bearing witness, and desire and pleasure, respectively. These modes buttress my call for a proliferation of ways the subject can be authored and be read.
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