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Title: Supervised Dimension Reduction Techniques for High-Dimensional Data
Creator: Molho, Dylan
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The data sets arising in modern science and engineering are often extremely large, befitting the era of big data. But these data sets are not only large in the number of samples they have, they may also have a large number of features, placing each data point in a high-dimensional space.However, unique problems arise when the dimension of the data has the same or even greater order than the sample size. This scenario in statistics is known as the High Dimension, Low Sample Size problem (HDLSS...
Show moreThe data sets arising in modern science and engineering are often extremely large, befitting the era of big data. But these data sets are not only large in the number of samples they have, they may also have a large number of features, placing each data point in a high-dimensional space.However, unique problems arise when the dimension of the data has the same or even greater order than the sample size. This scenario in statistics is known as the High Dimension, Low Sample Size problem (HDLSS). In this paradigm, many standard statistical estimators are shown to perform sub-optimally and in some cases can not be computed at all. To overcome the barriers found in HDLSS scenarios, one must make additional assumptions on the data, either with explicit formulations or with implicit beliefs about the behavior of the data. The first type of research leads to structural assumptions placed on the probability model that generates the data, which allow for alterations to classical methods to yield theoretically optimal estimators for the chosen well-defined tasks. The second type of research, in contrast, makes general assumptions usually based on the the causal nature of chosen real-world data application, where the data is assumed to have dependencies between the parameters.This dissertation develops two novel algorithms that successfully operate in the paradigm of HDLSS. We first propose the Generalized Eigenvalue (GEV) estimator, a unified sparse projection regression framework for estimating generalized eigenvector problems.Unlike existing work, we reformulate a sequence of computationally intractable non-convex generalized Rayleigh quotient optimization problems into a computationally efficient simultaneous linear regression problem, padded with a sparse penalty to deal with high-dimensional predictors. We showcase the applications of our method by considering three iconic problems in statistics: the sliced inverse regression (SIR), linear discriminant analysis (LDA), and canonical correlation analysis (CCA). We show the reformulated linear regression problem is able to recover the same projection space obtained by the original generalized eigenvalue problem. Statistically, we establish the nonasymptotic error bounds for the proposed estimator in the applications of SIR and LDA, and prove these rates are minimax optimal. We present how the GEV is applied to the CCA problem, and adapt the method for a robust Huber-loss based formulation for noisy data. We test our framework on both synthetic and real datasets and demonstrate its superior performance compared with other state-of-the-art methods in high dimensional statistics. The second algorithm is the scJEGNN, a graphical neural network (GNN) tailored to the task of data integration for HDLSS single-cell sequencing data.We show that with its unique model, the GNN is able to leverage structural information of the biological data relations in order to perform a joint embedding of multiple modalities of single-cell gene expression data. The model is applied to data from the NeurIPS 2021 competition for Open Problems in Single-Cell Analysis, and we demonstrate that our model is able to outperform top teams from the joint embedding task.
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Title: PRENATAL CANNABIS EXPOSURE AMONG PREGNANT PEOPLE IN TWO MICHIGAN SAMPLES
Creator: Vanderziel, Alyssa
Date: 2022
Collection: Electronic Theses & Dissertations
Description: This dissertation will address three study aims: Aim 1 will estimate the size of a suspected causal influence of prenatal cannabis exposure on a set of inter-related birth outcomes: birth size, gestational age, 5-minute Apgar score, and neonatal intensive care unit admission. Aim 2 will investigate the degree to which morning sickness might be associated with higher odds of cannabis use. Aim 3 is to conduct a feasibility study to assess the recruitment and retention of pregnant people who...
Show moreThis dissertation will address three study aims: Aim 1 will estimate the size of a suspected causal influence of prenatal cannabis exposure on a set of inter-related birth outcomes: birth size, gestational age, 5-minute Apgar score, and neonatal intensive care unit admission. Aim 2 will investigate the degree to which morning sickness might be associated with higher odds of cannabis use. Aim 3 is to conduct a feasibility study to assess the recruitment and retention of pregnant people who regularly use cannabis, measured by willingness to participate and complete the study survey; willingness to provide urine samples; the percentage of participants who are cannabis-only users; and the percentage of pregnant people retained for the three follow-up assessments. Aims 1 and 2 use data for the Michigan Archive for Research on Child Health, a prospective cohort of pregnant people recruited from 11 sites across Michigan between 2017 and 2021. Aim 1 and Aim 2 analytic sample sizes are n= 584 and n= 826, respectively. Results of Aim 1 suggest a modest but statistically significant association between prenatal cannabis exposure and birth size z-score after model adjustment for potential confounding variables (betamodel4= -0.3; 95% CI: -0.5, -0.003). Results of Aim 2 suggest higher odds of prenatal cannabis use with increasing morning sickness severity (ORmodel4= 1.2; 95% CI: 1.1, 1.2). Sensitivity analyses indicate higher odds of using cannabis during the first trimester with increasing morning sickness severity (ORmodel4= 1.1; 95% CI: 1.01, 1.2). Similarly, findings indicate higher odds of cannabis use in the second or third trimester of pregnancy with increasing morning sickness severity (ORmodel4= 1.2; 95% CI: 1.1, 1.4). Sensitivity analyses also suggest an association between pre-pregnancy and prenatal cannabis use and morning sickness severity (betamodel4= 0.1; 95% CI: 0.003, 0.2 and betamodel4= 0.2; 95% CI: 0.1, 0.2, respectively). For Aim 3, Cannabis Legalization in Michigan-Maternal & Infant Health, a prospective feasibility study, was designed to better understand the recruitment and retention of pregnant people who regularly use cannabis. The study recruited n= 77 baseline participants of which n= 15 were prospectively followed and assessed during each trimester of pregnancy and once post-delivery. Of the participants recruited at baseline, 42% reported using cannabis during pregnancy, of which 87% were cannabis-only users (i.e., no reported polysubstance use). All prospective participants were willing to provide urine samples; the concordance between self-reported cannabis use and urinalysis was 100% in the first and second trimesters and 92% in the third trimester of pregnancy. Study retention of the prospective sample was 80%; of n= 15 first trimester participants, n= 3 were loss-to-follow-up. Of the remaining 12 participants, 83% had complete data across all four timepoints.Findings from this dissertation reveal that pregnant people are willing to participate in a study that explores the health effects of prenatal cannabis use on birth outcomes and maternal health. Larger studies are warranted to assess the association between prenatal cannabis exposure and fetal growth and development, as well as the relationship between morning sickness and cannabis use. This dissertation also detected an association between prenatal cannabis exposure and lower birth size, suggesting that pregnant people, or people contemplating pregnancy, should be cautioned against using cannabis until more studies are conducted to establish causality between prenatal cannabis use and neonatal health.
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Title: SCATTERING AMPLITUDES FOR ZZ PRODUCTION AT THE LHC AND TOP-QUARK MASS EFFECTS
Creator: Agarwal, Bakul
Date: 2022
Collection: Electronic Theses & Dissertations
Description: With the Large Hadron Collider providing experimental data with unprecedented precision, theoretical predictions must improve similarly to keep up.Among a plethora of processes being studied at the LHC, the production of a pair of vector bosons is of particular importance. Consequently, precise theoretical predictions for these processes are necessary. This thesis discusses primarily the calculation of ZZ production through gluon fusion at 2-loops with full top-quark mass dependence as well...
Show moreWith the Large Hadron Collider providing experimental data with unprecedented precision, theoretical predictions must improve similarly to keep up.Among a plethora of processes being studied at the LHC, the production of a pair of vector bosons is of particular importance. Consequently, precise theoretical predictions for these processes are necessary. This thesis discusses primarily the calculation of ZZ production through gluon fusion at 2-loops with full top-quark mass dependence as well as the technological improvements required to successfully perform the calculation. Also discussed briefly is the quark initiated production of $\gamma\gamma + \text{jet}$ at 2-loops where some of these technologies allowed to overcome prior bottlenecks in the calculation of the helicity amplitudes.The 2-loop corrections for ZZ production through massless quarks had been known; in this work, the 2-loop corrections through the massive top quark are calculated .To achieve this, a new algorithm to systematically construct linear combinations of integrals with a convergent parametric integral representation is developed. This algorithm finds linear combinations of general integrals with numerators, dots, and dimension shifts as well as integrals from subsectors.To express the amplitudes in terms of these integrals, Integration-By-Parts (IBP) reduction is performed making use of syzygies and finite field based methods.A new algorithm is employed to construct these syzygies using linear algebra. The IBP reductions for $gg\rightarrow ZZ$ are successfully performed using these techniques. Further improvements, including predetermining the structure of the coefficients in IBP reductions, are used to successfully perform the reductions for $\gamma\gamma + jet$. Multivariate partial fractioning is used to simplify the final expressions to more manageable forms and render them suitable for fast numerical evaluation.%\thispagestyle{empty}In the case of $gg\rightarrow ZZ$, due to the presence of structures beyond polylogarithms, sector decomposition is employed to numerically evaluate the finite master integrals.Evaluating the amplitudes, agreement is found with previously calculated expansions specifically in the limit of large and small top mass. Improved results are presented for scattering at intermediate energies and/or for non-central scattering angles. With this calculation, the last building block required for the calculation of the full NLO cross-section for $gg\rightarrow ZZ$ is known.
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Title: REACTIVE ION ENHANCED MAGNETRON SPUTTERING OF NITRIDE THIN FILMS
Creator: Talukder, Al-Ahsan
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Magnetron sputtering is a popular vacuum plasma coating technique used for depositing metals, dielectrics, semiconductors, alloys, and compounds onto a wide range of substrates. In this work, we present two popular types of magnetron sputtering, i.e., pulsed DC and RF magnetron sputtering, for depositing piezoelectric aluminum nitride (AlN) thin films with high Young’s modulus. The effects of important process parameters on the plasma I-V characteristics, deposition rate, and the properties...
Show moreMagnetron sputtering is a popular vacuum plasma coating technique used for depositing metals, dielectrics, semiconductors, alloys, and compounds onto a wide range of substrates. In this work, we present two popular types of magnetron sputtering, i.e., pulsed DC and RF magnetron sputtering, for depositing piezoelectric aluminum nitride (AlN) thin films with high Young’s modulus. The effects of important process parameters on the plasma I-V characteristics, deposition rate, and the properties of the deposited AlN films, are studied comprehensively. The effects of these process parameters on Young’s modulus of the deposited films are also presented. Scanning electron microscope imaging revealed a c-axis oriented columnar growth of AlN. Performance of surface acoustic devices, utilizing the AlN films deposited by magnetron sputtering, are also presented, which confirms the differences in qualities and microstructures of the pulsed DC and RF sputtered films. The RF sputtered AlN films showed a denser microstructure with smaller grains and a smoother surface than the pulsed DC sputtered films. However, the deposition rate of RF sputtering is about half of the pulsed DC sputtering process. We also present a novel ion source enhanced pulsed DC magnetron sputtering for depositing high-quality nitrogen-doped zinc telluride (ZnTe:N) thin films. This ion source enhanced magnetron sputtering provides an increased deposition rate, efficient N-doping, and improved electrical, structural, and optical properties than the traditional magnetron sputtering. Ion source enhanced deposition leads to ZnTe:N films with smaller lattice spacing and wider X-ray diffraction peak, which indicates denser films with smaller crystallites embedded in an amorphous matrix.
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Title: Towards Robust and Reliable Communication for Millimeter Wave Networks
Creator: Zarifneshat, Masoud
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The future generations of wireless networks benefit significantly from millimeter wave technology (mmW) with frequencies ranging from about 30 GHz to 300 GHz. Specifically, the fifth generation of wireless networks has already implemented the mmW technology and the capacity requirements defined in 6G will also benefit from the mmW spectrum. Despite the attractions of the mmW technology, the mmW spectrum has some inherent propagation properties that introduce challenges. The first is that free...
Show moreThe future generations of wireless networks benefit significantly from millimeter wave technology (mmW) with frequencies ranging from about 30 GHz to 300 GHz. Specifically, the fifth generation of wireless networks has already implemented the mmW technology and the capacity requirements defined in 6G will also benefit from the mmW spectrum. Despite the attractions of the mmW technology, the mmW spectrum has some inherent propagation properties that introduce challenges. The first is that free space pathloss in mmW is more severe than that in the sub 6 GHz band. To make the mmW signal travel farther, communication systems need to use phased array antennas to concentrate the signal power to a limited direction in space at each given time. Directional communication can incur high overhead on the system because it needs to probe the space for finding signal paths. To have efficient communication in the mmW spectrum, the transmitter and the receiver should align their beams on strong signal paths which is a high overhead task. The second is a low diffraction of the mmW spectrum. The low diffraction causes almost any object including the human body to easily block the mmW signal degrading the mmW link quality. Avoiding and recovering from the blockage in the mmW communications, especially in dynamic environments, is particularly challenging because of the fast changes of the mmW channel. Due to the unique characteristics of the mmW propagation, the traditional user association methods perform poorly in the mmW spectrum. Therefore, we propose user association methods that consider the inherent propagation characteristics of the mmW signal. We first propose a method that collects the history of blockage incidents throughout the network and exploits the historical blockage incidents to associate user equipment to the base station with lower blockage possibility. The simulation results show that our proposed algorithm performs better in terms of improving the quality of the links and blockage rate in the network. User association based only on one objective may deteriorate other objectives. Therefore, we formulate a biobjective optimization problem to consider two objectives of load balance and blockage possibility in the network. We conduct Lagrangian dual analysis to decrease time complexity. The results show that our solution to the biobjective optimization problem has a better outcome compared to optimizing each objective alone. After we investigate the user association problem, we further look into the problem of maintaining a robust link between a transmitter and a receiver. The directional propagation of the mmW signal creates the opportunity to exploit multipath for a robust link. The main reasons for the link quality degradation are blockage and link movement. We devise a learning-based prediction framework to classify link blockage and link movement efficiently and quickly using diffraction values for taking appropriate mitigating actions. The simulations show that the prediction framework can predict blockage with close to 90% accuracy. The prediction framework will eliminate the need for time-consuming methods to discriminate between link movement and link blockage. After detecting the reason for the link degradation, the system needs to do the beam alignment on the updated mmW signal paths. The beam alignment on the signal paths is a high overhead task. We propose using signaling in another frequency band to discover the paths surrounding a receiver working in the mmW spectrum. In this way, the receiver does not have to do an expensive beam scan in the mmW band. Our experiments with off-the-shelf devices show that we can use a non-mmW frequency band's paths to align the beams in mmW frequency. In this dissertation, we provide solutions to the fundamental problems in mmW communication. We propose a user association method that is designed for mmW networks considering challenges of mmW signal. A closed-form solution for a biobjective optimization problem to optimize both blockage and load balance of the network is also provided. Moreover, we show that we can efficiently use the out-of-band signal to exploit multipath created in mmW communication. The future research direction includes investigating the methods proposed in this dissertation to solve some of the classic problems in the wireless networks that exist in the mmW spectrum.
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Title: CLIMATIC VARIABILITY AND CHANGE IN THE MIDWESTERN UNITED STATES : IMPLICATIONS FOR NITROGEN LEACHING IN AGRICULTURAL SYSTEMS
Creator: Baule, William James
Date: 2022
Collection: Electronic Theses & Dissertations
Description: How has the background climate of the Midwestern United States changed over recent decades and how has this affected nitrate leaching? These are the core questions addressed in this dissertation, through three self-contained studies focused on different aspects of the climate-agriculture interface in the Midwestern United States. In Chapter 2, statistical methods are used to quantify the solar radiation biases present in a widely used reanalysis-based hydrometeorological dataset over space,...
Show moreHow has the background climate of the Midwestern United States changed over recent decades and how has this affected nitrate leaching? These are the core questions addressed in this dissertation, through three self-contained studies focused on different aspects of the climate-agriculture interface in the Midwestern United States. In Chapter 2, statistical methods are used to quantify the solar radiation biases present in a widely used reanalysis-based hydrometeorological dataset over space, implement statistical bias correction and interpolation to address the spatial nature of this bias, and quantify the impacts of the solar radiation bias and proposed correction on simulated maize yields and water stress. Correction of reanalysis solar radiation alone brought simulated yield and water usage more in line with simulations forced with in-situ solar radiation. Chapter 3 examines changes in precipitation, utilizing a unique approach to station screening during the period 1951-2019 over a region encompassing the Great Lakes and broader Midwestern regions, of the United States. A multiple tier procedure was utilized to identify high quality input data series from the Global Historical Climatology Network-Daily dataset. Temporal and spatial trends were analyzed for a broad range of related annual and seasonal indicators ranging from accumulated totals and frequency of threshold events to event duration and potential linkages with total precipitable water. Our analyses confirm the results of previous studies while providing unique insights to data quality and seasonality. The trends of the indicators in our study exhibited more cohesive spatial patterns and temporal similarities when compared with studies with different quality control criteria, illustrating the importance of quality control of observations in climatic studies and highlighting the complexity of the changing character of precipitation. In Chapter 4, System Approach to Land Use Sustainability, a process-based crop model was applied with gridded soil and meteorological data using a yield stability zone concept to simulate corn and soybean production in 14 Midwestern states at the sub-field scale during the 1989-2019 period. Five zones based on multi-year yield stability were simulated for each field at 30m x 30m resolution, with zones being relative to each individual field. Outputs were evaluated using a nitrogen balance approach to establish zone-specific statistical distributions of nitrate leaching across the 14 states, specifically highlighting periods with changing and highly variable precipitation. Results indicate that low stable, unstable hill tops, and unstable slope zones are associated with an outsized contribution to overall nitrate leaching and that unstable zones exhibit variable year-to-year response to weather tied to their position in the landscape. Spatial analysis of the results suggests leaching is tied to precipitation variability, water stress, and total precipitation amount. In aggregate, the chapters presented here highlight the interconnectedness of the soil-plant-atmosphere continuum to changes in hydrologic regime and sensitivity to the biases in the data used to conduct analyses, run models, and from which conclusions are drawn. The study findings shed light on the potential for improved management of agricultural fields and illustrate how process-based crop models can be useful for designing management practices to reduce environmental pollution and increase profits to producers.
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Title: EPIDEMIOLOGY, EVOLUTION, AND DIAGNOSTICS OF TUBERCULOSIS IN HUMANS AND ANIMALS
Creator: Hadi, Syeda Anum
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Tuberculosis control in animals and humans alike requires early detection of Mycobacterium tuberculosis complex as well as current knowledge about the transmission patterns of the disease in the respective populations. These two building blocks provide the foundation on which the disease control programs can build their policies to expediate control efforts. In this thesis we amalgamate molecular epidemiology, genomics, and proteomics. We studied the transmission pattern of M. tuberculosis...
Show moreTuberculosis control in animals and humans alike requires early detection of Mycobacterium tuberculosis complex as well as current knowledge about the transmission patterns of the disease in the respective populations. These two building blocks provide the foundation on which the disease control programs can build their policies to expediate control efforts. In this thesis we amalgamate molecular epidemiology, genomics, and proteomics. We studied the transmission pattern of M. tuberculosis and its evolution within a marginalized population. The patterns led to the identification of gaps in TB control policies in marginalized populations with little access to healthcare. Similarly, we studied the genomewide polymorphisms in a naturally attenuated strain - M. bovis strain Ravenel to elucidate possible mechanisms for its reduced virulence and pathogenicity. Insights gained from genome sequence analysis in conjunction with pathogenesis study for M. bovis Ravenel paved the pathway to defining the complex and multi-faceted reasons for attenuation of the oldest bacteria of the world. Next, pathogen-specific biomarkers were evaluated to assist in unambiguous disease detection across multiple host species. Discovery and validation of biomarkers work facilitated the field diagnostic applications for TB in animals and humans. This three-pronged approach developed in this study, understanding the genomic basis of attenuation, and enhanced field TB diagnostics in the animal-human interface.
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Title: CHARACTERIZATION OF MANUAL EXPLORATORY BEHAVIORS IN EARLY CHILDHOOD
Creator: Patel, Priya Prakashbhai
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Manual exploratory behaviors observed during early childhood have critical functional and clinical role in the motor development of a child (Lockman & Kahrs, 2017). This dissertation is aimed to (1) address the challenges faced in the quantitative analysis of these behaviors, (2) conduct quantitative analysis of two important manual exploratory behaviors, (3) extend the current knowledge on the effects of age and object properties on these behaviors beyond infancy by assessing them in...
Show moreManual exploratory behaviors observed during early childhood have critical functional and clinical role in the motor development of a child (Lockman & Kahrs, 2017). This dissertation is aimed to (1) address the challenges faced in the quantitative analysis of these behaviors, (2) conduct quantitative analysis of two important manual exploratory behaviors, (3) extend the current knowledge on the effects of age and object properties on these behaviors beyond infancy by assessing them in preschoolers. In Study 1, a machine learning (ML) -based automated classification system was developed as a proof-of-concept for the classification of manual exploratory behaviors that address the challenges encountered in the quantitative analysis of these behaviors. This system was developed using data from adult participants and it can currently classify three manual exploratory behaviors namely- rotation, throwing and fingering with substantially higher accuracy than chance level (average accuracy = 85.0 + 4.16%). Based on these findings, ML -based approach appears to be both- a feasible and a scalable alternative to conventional video coding for identifying the manual exploratory behaviors on time series; thereby, facilitating their quantitative assessment. In Study 2, quantitative assessment of two important manual exploratory behaviors- rotation and throwing was conducted along with the assessment of ML classifiers on data from children (3 – 5 years old). The ML classifiers showed substantial decrease in performance owing to differences in movements between children and adults as well as technical difficulties. Rotation behaviors became more variable and faster with increasing age while the characteristics of throwing behaviors were inconclusive of developmental differences across the three ages. In Study 3, the effects of age and three object properties (size, shape and texture) were assessed on the qualitative characteristics of manual exploratory behaviors in children (3 – 5 years old). Manual exploration of objects was driven at different levels by age and object properties in preschoolers. In terms of age, throwing behaviors were more common in the 3-year group while rotational behaviors in the 5-year group. In terms of the three object properties, object size and shape directed child’s hand preference in reaching objects while object size and texture influenced their manual exploratory behaviors. In addition, object texture was found to mainly influence child’s first interactions with the objects as the squeezing and fingering behaviors occurred more often during the first interactions with the objects. The findings suggest that the dynamic interplay between learning to perceive object properties and manually exploring them continues to develop and adapt beyond infancy. In summary, manual exploratory behaviors, similar to other motor behaviors, are influenced by different individual, task and environment factors. These effects continue beyond infancy and throughout early childhood. A thorough qualitative and quantitative assessment is required to fully understand their functional and clinical role in early childhood. For this, ML -based approach is recommended to address the challenges in their quantitative analysis and to facilitate the overall scope of investigating these behaviors.
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Title: Nucleon and pion gluon parton distribution function from lattice QCD calculation
Creator: Fan, Zhouyou
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Parton distribution functions (PDFs) are important to characterize the structure of the hadrons such as protons and neutrons. The contribution to the structure from quarks has been studied in detail during the past few decades. The structure in the gluon sector is also important but less studied. For high-energy hadrons, the gluon contribution dominates at small $x$, where $x$ is the momentum fraction carried by a quark or gluon. At large $x$, the uncertainty of the gluon PDF is large,...
Show moreParton distribution functions (PDFs) are important to characterize the structure of the hadrons such as protons and neutrons. The contribution to the structure from quarks has been studied in detail during the past few decades. The structure in the gluon sector is also important but less studied. For high-energy hadrons, the gluon contribution dominates at small $x$, where $x$ is the momentum fraction carried by a quark or gluon. At large $x$, the uncertainty of the gluon PDF is large, especially compared to that of the quark PDFs at large $x$. Gluon PDFs for nucleons and pions are mostly extracted from global analysis of experimental data using perturbation theory as a guide. Theoretically, lattice QCD provides an independent non-perturbative theoretical approach to calculate the gluon PDFs.We present the exploratory study of nucleon gluon PDFs from lattice QCD using the quasi-PDF approach. Using valence overlap fermions on the $2+1$-flavor domain-wall fermion gauge ensemble, the quasi-PDF matrix elements we obtain agree with the Fourier transform of the global-fit PDF within statistical uncertainty. We further study the $x$-dependent nucleon and pion gluon distributions via the pseudo-PDF approach on lattice ensembles with $2+1+1$ flavors of highly improved staggered quarks (HISQ) generated by the MILC Collaboration. Using clover fermions for the valence action, and adding momentum smearing, PDFs are found for pion boost momenta up to 2.56~GeV. Several lattice sizes and spacings ($a\approx 0.9, 0.12$ and 0.15~fm) were evaluated, resulting in three pion masses, $M_{\pi}\approx 220$, 310 and 690~MeV/$c^2$.
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Title: THE IMPACT OF THE AFFORDABLE CARE ACT ON UNINTENDED PREGNANCY
Creator: MacCallum-Bridges, Colleen Lynn
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Background & Objectives: Nearly half of all pregnancies in the United States (US) are unintended (i.e., mis-timed or unwanted), and roughly 5% of US women experience an unintended pregnancy each year, suggesting the population-level need for contraceptives is not being met. Further, these pregnancies are experienced disproportionately by women who are younger, women of color, and women of lower socioeconomic status – indicating these groups are particularly underserved. The Patient Protection...
Show moreBackground & Objectives: Nearly half of all pregnancies in the United States (US) are unintended (i.e., mis-timed or unwanted), and roughly 5% of US women experience an unintended pregnancy each year, suggesting the population-level need for contraceptives is not being met. Further, these pregnancies are experienced disproportionately by women who are younger, women of color, and women of lower socioeconomic status – indicating these groups are particularly underserved. The Patient Protection and Affordable Care Act (ACA) had the potential to improve our ability to meet this population-level need by increasing access to and affordability of contraceptive products and services. There is evidence that the ACA increased health insurance coverage and is associated with an increase in the use of highly effective long-acting reversible contraceptives, but it is unclear whether these effects translated into fewer unintended pregnancies. Further, it is unknown whether these effects were equitably distributed across race and ethnicity. Thus, the objectives of this dissertation are to: 1) estimate the overall impact of the ACA on unintended pregnancy, and if evidence of an impact exists, describe the timing of this impact, 2) explore three mechanisms of the ACA by investigating the impact of three major provisions (i.e., the dependent coverage provision, Marketplace subsidies, and ACA insurance expansions), and 3) assess the impact of the ACA on racial/ethnic disparities in unintended pregnancy. Methods: Data from multiple cross-sectional cycles of the National Survey of Family Growth (NSFG) were used. NSFG uses a multistage probabilistic sampling methodology to survey non-institutionalized civilian men and women regarding family planning, marriage, divorce, and both general and reproductive health. I included sexually active female respondents aged 18-44 interviewed between 2006 and 2019 (n=25,426). To address objectives (1) and (2) I used a difference-in-differences approach to compare trends in unintended pregnancy between women who were eligible to benefit from the intervention (the overall ACA or one of the listed components), to that of women who were ineligible to benefit. Eligibility was determined by respondent age and income. To address objective (3), I used a pre/post analysis to explore how racial/ethnic disparities in unintended pregnancy differed prior to and following enactment of the overall ACA and its components. Results: There was evidence that: 1) the overall ACA was associated with a 2.1 percentage point (ppt) decrease in unintended pregnancy among eligible women, and this decrease was fairly consistent during and following the ACA’s implementation period, 2) the dependent coverage provision was associated with a large (8.2 ppt) decrease in unintended pregnancy among lower income young women, and 3) the disparities in unintended pregnancy between Hispanic and non-Hispanic (NH) White women and between NH Black and NH White women decreased by 2.9 ppt and 4.1 ppt, respectively, among eligible women following full implementation of the ACA. There was insufficient evidence that the Marketplace subsidies or insurance expansions were associated with unintended pregnancy, or that the dependent coverage provision, Marketplace subsidies, or insurance expansions were associated with racial/ethnic disparities in unintended pregnancy. Conclusions: The overall ACA and the dependent coverage provision may be associated with reductions in unintended pregnancy, and the magnitude of these associations appear to differ across sociodemographic subgroups (i.e., income, race/ethnicity) – holding implications for health equity. These findings provide insight regarding how the ACA works to influence reproductive health, and for whom – which is critical information for both researchers and public policy makers who seek to improve reproductive health and health equity.
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Title: THE MEASUREMENT OF PHYSICAL ACTIVITY SELF-EFFICACY IN INTERVENTIONS THAT PROMOTE PHYSICAL ACTIVITY IN ADULTS
Creator: Bateman, Andre Godfrey
Date: 2022
Collection: Electronic Theses & Dissertations
Description: This dissertation comprises two studies focused on the measurement of self-efficacy associated with physical activity-promoting interventions in adults. Recent research indicates that most adults do not achieve sufficient daily physical activity for health. The research also shows that adults with obesity are even less likely to engage in sufficient physical activity for health. Physical inactivity is associated with negative health outcomes such as cardiovascular disease and is therefore a...
Show moreThis dissertation comprises two studies focused on the measurement of self-efficacy associated with physical activity-promoting interventions in adults. Recent research indicates that most adults do not achieve sufficient daily physical activity for health. The research also shows that adults with obesity are even less likely to engage in sufficient physical activity for health. Physical inactivity is associated with negative health outcomes such as cardiovascular disease and is therefore a major public health concern. There is however evidence that certain motivational constructs, such as self-efficacy are associated with increased physical activity in adults. As a result, behavioral interventions utilizing these constructs as modifiable mediators of physical activity behavior have been employed to increase physical activity in different populations.Study 1 is a systematic review focused on examining the theoretical and measurement quality of physical activity self-efficacy scales in physical activity-promoting interventions for adults. The search strategy was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. One hundred sixteen studies were reviewed, from which the physical activity self-efficacy scales were identified and extracted. Of the scales identified, 14 were multi-item and five were single item scales. The systematic review uncovered that the identified scales had varying conceptual and measurement related properties despite having good administrative quality in general. The major issues identified with self-efficacy measurement were: (a) a lack of concordance between self-efficacy and physical activity measurement, (b) a lack of specified physical activity levels to which the self-efficacy measurements refer, (c) self-efficacy scales described with theoretically imprecise construct labels, (d) a lack of emphasis on essential conceptual properties of self-efficacy scales, (e) a lack of specification of the dimensionality of self-efficacy scales and (f) the use of single-item measures of self-efficacy. Essential conceptual and measurement related recommendations were made in response to these issues to improve the measurement of physical activity self-efficacy in physical activity-promoting interventions. Study 2 employed a latent variable approach to explore the dimensionality, temporal invariance, and external validity of responses to the self-efficacy to regulate physical activity scale (SERPA). The SERPA is a modified version of the barriers self-efficacy scale. This study analyzed data from the Well-Being and Physical Activity Study (WBPA; ClinicalTrials.gov, identifier: NCT03194854). The WBPA consisted of 461 participants at baseline which decreased to 427 participants at 30 days post baseline. The WBPA deployed the Fun For Wellness (FFW) intervention. One objective of the FFW intervention was to promote physical activity in adults with obesity. A two-dimensional factor structure explained responses to the SERPA at baseline. Factor 1 was conceptualized as self-efficacy to regulate barriers to physical activity participation based on social considerations. Factor 2 was conceptualized as self-efficacy to regulate internally perceived barriers to physical activity participation. There was strong evidence for the effectiveness of the FFW intervention to exert a direct effect on the proposed two-dimensional structure of latent self-efficacy to regulate physical activity in adults with obesity at 30 days post-baseline.
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Title: A PLACE OF PERSONAL AND CULTURAL RESISTANCE : USING BLACK FEMINIST VALUES, PERSPECTIVES, AND EMBODIED KNOWLEDGES TO (RE)EXAMINE INSTITUTIONAL LOGICS AND ETHICS IN DIGITAL RESEARCH
Creator: Haywood, Constance Monique
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Centering the experiences and practices of Black women scholars who engage research in areas of Black technological and digital engagement, this dissertation examines how Black women and Black feminist-identifying digital researchers’ personal, cultural, and professional identities inform methodological and ethical decision-making in their work. Building on the theoretical approaches of Black feminist thinkers like Patricia Hill Collins and the Combahee River Collective, this project...
Show moreCentering the experiences and practices of Black women scholars who engage research in areas of Black technological and digital engagement, this dissertation examines how Black women and Black feminist-identifying digital researchers’ personal, cultural, and professional identities inform methodological and ethical decision-making in their work. Building on the theoretical approaches of Black feminist thinkers like Patricia Hill Collins and the Combahee River Collective, this project addresses the complexities of digital ethics by 1) examining how Black women’s unique, lived experience(s) both inform and are impacted by their work and 2) uncovering the processes that support -- and sometimes create tensions with -- research aroundBlack digital publics, users, and spaces. This project places a special focus on the work of Black women and Black feminist-identifying scholars in writing studies-related fields, collecting and analyzing data from multiple qualitative interviews amongst five research participants.Ultimately, this dissertation highlights the growing work and practices of Black women digital researchers, using Black feminist theory as a means to uncover how Black women researchers reconsider, repurpose, and reapproach their research practices from embodied and critical standpoints. This project also adds to growing conversations around the development ofdigital methodologies in writing and communication-related fields, particularly those that place a greater priority on researchers’ ethical responsibilities to multiple-marginalized technology users and communities.
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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: THE ROLE OF HOST-PARASITOID INTERACTIONS, RAPID EVOLUTION, AND HOST SHIFTS IN THE BIOLOGICAL CONTROL OF INVASIVE INSECT PESTS
Creator: Linder, Shelley Kay
Date: 2022
Collection: Electronic Theses & Dissertations
Description: This thesis focuses on two invasive species, spotted wing drosophila (Drosophila suzukii) and the brown marmorated stink bug (Halyomorpha halys). The first chapter investigates the potential of native parasitoids to increase their developmental success on D. suzukii. Two native parasitoids were subjected to 10 generations of selection on D. suzukii and fitness metrics were measured in generations 0, 3, and 10. Both parasitoid species responded rapidly to selection, reaching peak developmental...
Show moreThis thesis focuses on two invasive species, spotted wing drosophila (Drosophila suzukii) and the brown marmorated stink bug (Halyomorpha halys). The first chapter investigates the potential of native parasitoids to increase their developmental success on D. suzukii. Two native parasitoids were subjected to 10 generations of selection on D. suzukii and fitness metrics were measured in generations 0, 3, and 10. Both parasitoid species responded rapidly to selection, reaching peak developmental success on the novel host within three generations, which they then maintained for seven additional generations. There was no increase in preference towards the novel host or changes in development time or body size associated with adaptation. The sex ratio became less female biased for both parasitoids after three generations of selection but rebounded in one species by generation 10. These results indicate that artificial selection can increase the performance of native parasitoids within a few generations and may be used to improve biocontrol when co-adapted natural enemies of invasive species are not available. The second chapter investigates how the fitness of the adventive parasitoid of H. halys, Trissolcus japonicus, may change in response to intermittent or continuous exposure to a non-target native stink bug species. Acceptance of the native stink bug species did not increase with either intermittent or continuous exposure. However, reproduction on the native host resulted in a significant fitness cost for T. japonicus and compromised the fitness of the parasitoid on its original host species. These results suggest that non-target effects of T. japonicus may remain insignificant in nature given the fitness cost of attacking native species.
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Title: THE EFFECT OF CLAW REMOVAL METHODS AND TEMPERATURE ON THE POST-RELEASE SURVIVAL AND CRITICAL THERMAL MAXIMUM OF STONE CRAB (MENIPPE MERCENARIA)
Creator: Walus, Alexandria Marie
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Florida stone crab (Menippe mercenaria) is an emerging commercial fishery in the Bahamas with its main export to the United States of America. This fishery capitalizes on the oversized claws of the crab, which are harvested, before the crab is returned to the sea where it can potentially regrow its claws. While it is often assumed that the crab will regrow its claws and re-enter the fishery, only 13% of harvested crabs in the fishery have regrown claws, and an estimated 2-81% of crabs survive...
Show moreFlorida stone crab (Menippe mercenaria) is an emerging commercial fishery in the Bahamas with its main export to the United States of America. This fishery capitalizes on the oversized claws of the crab, which are harvested, before the crab is returned to the sea where it can potentially regrow its claws. While it is often assumed that the crab will regrow its claws and re-enter the fishery, only 13% of harvested crabs in the fishery have regrown claws, and an estimated 2-81% of crabs survive post-claw removal and release. In addition, the Caribbean region is considered one of the most vulnerable areas with respect to climate change. Therefore, because most aquatic organisms cannot regulate their body temperature, they are directly influenced by environmental temperature stress, and when combined with the stress of claw removal may further decrease the capacity of the crab to survive warming temperatures. The purpose of my thesis was to: 1) determine a method of claw removal that maximizes survival for stone crab, 2) determine the effect of rapidly warming water temperatures on the reflex behavior of crabs post-release, and 3) determine the effect of claw removal on the critical thermal maximum (CTMax) of stone crab. In chapter 1, I used a controlled laboratory experiment to compare a new autotomy-inducing technique to the typical method of claw removal. For the two different claw removal methods, I compared the survival and start time for claw regeneration as a function of harvester experience and whether one claw or both claws were removed. Finally, the claws that were removed were inspected by independent observers to determine whether any differences using the two methods could be identified. Overall, I found that crabs with claws removed using the proposed induced autotomy method had significantly higher survival than crabs with claws removed using the typical method, while crabs with claws removed by inexperienced harvesters had the lowest. In Chapter 2, I conducted a series of laboratory experiments to measure nine reflex action mortality predictor reflexes of crabs and determine the critical thermal maximum (CTMax) for stone crab that had one or two claws removed using induced-autotomy. Of the nine reflexes used to develop an endpoint necessary for calculating CTMax, three were determined to be suitable (equilibrium, mouth closure and appendage turgor) and CTMax was 37.6 °C, and independent of the number of claws removed using the proposed induced-autotomy method. Overall, the tool required to conduct the induced-autotomy method of claw removal is simple and easily purchased or constructed and can easily be taught to recreational and commercial harvesters as a way to improve survival and thus sustainability of this important fishery.
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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: Multiple Jeopardy, Serious Mental Illness, and Service Attendance
Creator: Reid, Mallet R.
Date: 2022
Collection: Electronic Theses & Dissertations
Description: For people with Serious Mental Illness (SMI), attendance to behavioral health care services is linked to a an increased probability of recovery and a decreased risk for suicide, involuntary hospitalization, incarceration, mental distress, and preventable mortality. Within the population of people with SMI, women and men who are Black, Indigenous, and other People of Color (BIPoC) are most likely to experience barriers to services and are the least likely groups to attend services. Thus, most...
Show moreFor people with Serious Mental Illness (SMI), attendance to behavioral health care services is linked to a an increased probability of recovery and a decreased risk for suicide, involuntary hospitalization, incarceration, mental distress, and preventable mortality. Within the population of people with SMI, women and men who are Black, Indigenous, and other People of Color (BIPoC) are most likely to experience barriers to services and are the least likely groups to attend services. Thus, most studies examining behavioral health care attendance trends for people with SMI focus on the relationship between marginalized race and/or sex and barriers to service attendance. However, few studies examine the relationship between barriers and attendance among those who occupy multiple marginalized identity groups. This study seeks to fill that gap. Using Multiple Jeopardy theory, which asserts that membership in multiple marginalized groups increases the risk of experiencing negative life events, this study examines the impact of holding multiple marginalized social group identities and of experiencing barriers to attendance on the probability of attending behavioral health services among people with SMI.
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Title: PRETERM DELIVERY AND ITS ASSOCIATION WITH FALSE POSITIVE, AUDITORY BRAINSTEM RESPONSE (ABR)-BASED NEWBORN HEARING SCREENING FINDINGS
Creator: Rathore, Mandavni
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Newborn hearing screening failure can occur in infants without hearing loss; these false-positive (FP) results have been speculated to reflect neurodevelopmental disorder risk. Preterm birth (PTB), a known neurodevelopmental risk factor, has been associated with FP at initial screening. We aim to further characterize this association by stratifying PTB by gestational age and delivery circumstance. To do this, we analyzed birth certificate and Early Hearing Detection & Intervention data from...
Show moreNewborn hearing screening failure can occur in infants without hearing loss; these false-positive (FP) results have been speculated to reflect neurodevelopmental disorder risk. Preterm birth (PTB), a known neurodevelopmental risk factor, has been associated with FP at initial screening. We aim to further characterize this association by stratifying PTB by gestational age and delivery circumstance. To do this, we analyzed birth certificate and Early Hearing Detection & Intervention data from the Michigan Dept. of Health & Human Services (2007–2015; n = 919,363). We restricted our analysis to singleton live births with available ABR-based hearing screening data and obstetric estimates of gestational age (n = 655,079). We then used logistic regression to evaluate the association of PTB defined by gestational age (extreme: < 28 weeks; moderate: 28–34 weeks; late: 34–36 weeks) and delivery circumstance (spontaneous, medically indicated) with FP, using full-term birth (≥ 37 weeks) as the referent group. Approximately 4% of infants had FP findings. All gestational age categories were associated with this phenomenon (extreme: OR = 4.2, 95% CI 3.7, 4.7; moderate: OR = 1.2, 95% CI 1.1, 1.3; late: 1.6, 95% CI 1.5, 1.7). Spontaneous and medically indicated PTB were also associated with FP (OR = 1.7, 95% CI 1.6, 1.8; OR = 1.4, 95% CI 1.3, 1.5, respectively). All results persisted following adjustment for socio-demographic and antepartum factors except for moderate PTB (OR = 1.0, 95% CI 0.9, 1.1), though sensitivity analyses suggested marked heterogeneity within this group. Further research is needed to investigate factors underlying these differences and whether they correlate with neurodevelopmental disorder diagnoses.
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