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Long Term Effect of Gingivoperiosteoplasty on Maxillary Development in Patients with Cleft Lip and Palate
No full textCleft lip and palate is one of the most common congenital craniofacial anomalies, affecting approximately 1.42 per 1,000 live births in the United States. Significant progress has been made in understanding cleft lip and palate, but there remains no consensus on the ideal treatment protocol. Gingivoperiosteoplasty (GPP), which aims to create a mucoperiosteal bridge across the alveolar cleft, is a procedure that may be added at the time of the primary lip closure. A benefit of GPP is that it may decrease the chance of future alveolar bone grafting by creating a bony bridge between the segments before teeth erupt. Another benefit may be reduction in oronasal fistulas. However, it has been debated that the GPP procedure may restrict maxillary growth and create more severe malocclusions. In our study, 35 unilateral complete cleft lip and palate patients all treated in the same tertiary hospital with a Latham appliance and primary lip repair were examined. A Latham appliance is a device that is placed in patients with unilateral complete cleft lip and palate at 2-5 months old prior to both lip repair and GPP. It is used to align the upper jaw segments and reduce the width of the cleft. The non-GPP group consisted of 11 patients who received a Latham appliance prior to primary lip repair. The GPP group consisted of 24 patients who received both a Latham appliance prior to primary lip repair and the GPP procedure during the lip repair. CBCT radiographs were taken on all patients at 6-8 years and were used to measure the maxilla in all three planes of space. Lateral and posterior-anterior cephalograms were extracted from the CBCT and traced. The same researcher traced all cephalograms at two different time points. In the sagittal plane ANS-PNS, SNA, and A-N perpendicular were measured. In the vertical plane UFH: LFH was used. And in the transverse plane, Jugal-Jugal was measured. By comparing the two groups, we are able to analyze if the GPP procedure results in an increase in maxillary hypoplasia. Statistical analysis was completed using a t test to compare the means between the two groups. Statistical significance was defined as having a p value less than 0.05. The analysis revealed that there is no statistical significant increase in hypoplasia of the maxilla in the sagittal and vertical dimension, but there was a statistical significant difference in the transverse dimension measured by jugal-jugal. While the treatment of cleft lip and palate remains at discord, these results provide valuable insight that can be used for creating protocols and surgical strategies in treating patients with cleft lip and palate.Orthodontic
Pick Six: Estimating the Return to School Selection for Elite College Football Recruits
No full textThe role of the university in the market for football talent is that of an interme- diary: high school players must pass through the NCAA en route to playing at the professional level in the NFL. As such, the choice of the university for elite football recruits is one that is taken seriously, given the way in which it serves as a critical final hurdle before a potentially lucrative professional career. While conventional wis- dom would suggest that the quality of the college program for which a recruit chooses to play may impact professional outcomes, I find, using college football recruitment data from ESPN and techniques from the literature on the returns to education, that controlling for unobservable individual-level attributes reveals that school choice has no statistically significant effect on probability of being drafted. Rather, I find that individual attributes are far more predictive of outcomes than school choice, suggesting misallocation of time and effort as well as suboptimal decision-making on the part of elite college football recruits.Applied Mathematic
Developing and Implementing Automated Solutions for Vaccine Development
No full textVaccines are generally accepted to be amongst the most efficacious, safe, and cost-effective medical interventions to prevent and treat infectious diseases. However, pathogens are constantly evolving and pose unique challenges to vaccine development. One major bottleneck in vaccine development is the need to accelerate development and deployment. Thus, we developed a platform to rapidly and accurately characterize the biophysical properties of potential vaccine candidates. Customized automation scripts were designed for sample preparation of two biophysical assays on a programmable robotic liquid handler. Screening a range of soluble protein constructs using these scripts reduced manual effort time, increased assay throughput, and had comparable accuracy to manual efforts. Overall, this approach demonstrates the potential for automation to transform early vaccine development pipelines by reducing turnaround time, optimizing resource use, and minimizing assay variability. Streamlining these processes will enable a rapid response to combat emerging and re-emerging infectious diseases.Extension Studie
Cross-validation Inference, Relative Algorithmic Stability, and Machine Learning Application in Robotic Grasping
No full textThis dissertation advances the theory of cross-validation, highlights the critical role of algorithmic stability in ensuring valid inference for cross-validation, and introduces a hybrid approach to grasp stability prediction.
In Chapter 1, we address a fundamental problem relevant to both the statistical and machine learning communities. With the surge in the number of algorithms being developed, it is crucial to perform statistically sound evaluation and comparison of algorithms.
We derive central limit theorems and consistent variance estimators for cross-validation under very mild stability conditions on the learning algorithm. Leveraging these results allows us to develop practical, asymptotically exact confidence intervals for evaluation of the test error, and also valid, powerful hypothesis tests for algorithm comparison. Notably, our results are applicable to any choice for the number of folds, thus including the popular setting of leave-one-out cross-validation.
In Chapter 2, we demonstrate the importance of evaluating the stability of algorithms in a relative sense for cross-validation inference. We prove that the Lasso algorithm, considered individually in the setting of single algorithm evaluation, has sufficient stability to ensure statistical soundness of cross-validation for that task, while a difference of two Lasso algorithms, in the comparison setting, does not.
In Chapter 3, we tackle the problem of grasp stability prediction in robotic grasping using a three-stage approach. We start with the estimation of key quantities critical to understanding grasp stability, known as the grasp parameters. Next, we predict the changes in contact forces caused by external disturbances. This, in turn, enables us to create an instance-by-instance slip prediction method. We develop a hybrid approach that combines physics and machine learning at each stage, effectively mitigating the limitations of both disciplines while leveraging their respective strengths. The experimental validation of this approach involved building an instrumented robot hand, designing experiments and collecting data.Statistic
A Technophilosophical Exploration of the Simulation Hypothesis and Virtual Reality Technology
No full textThe simulation hypothesis states that we are living in a computer simulation. That is, our reality is and always has been a simulated virtual reality. Philosophers typically classify the simulation hypothesis as a radical skeptical scenario—a scenario that brings into question our ability to have certain knowledge about the real world outside our own minds. In my thesis, I argue that our epistemological evaluation of the simulation hypothesis, as a radical skeptical scenario, depends on our metaphysical intuitions. Our metaphysical intuitions are our intuitions about the nature of reality that can fall on a continuum between two paradigmatic metaphysical views: subjective idealism and realism. Although subjective idealism may better resolve the worries of radical skepticism, subjective idealism is often seen as a radical metaphysical view.
My thesis—as a project in technophilosophy—explores the influences of VR technology on our understanding of the nature of reality. In my thesis, I argue that experiencing presence—the subjective feeling of "being there" in a virtual world—may lead to shifts in the user's metaphysical intuitions away from realism and towards idealism. To empirically test this hypothesis, I present a mixed-methods study that investigates the effects of presence in a VR environment on the user's metaphysical intuitions. In a study of 22 participants, I show that participants who experienced presence in a VR environment were significantly more open to and accepting of radical metaphysical views—such as subjective idealism—than participants who did not. I interpret the results from the study along three thematic aspects of metaphysical intuition: the nature of virtual reality, the subjectivity of reality, and the plurality of reality. I put forward a novel causal theory to explain the mechanism by which VR produces these effects on the user. Finally, I discuss the implications of these findings on our metaphysical understanding and our evaluation of the simulation hypothesis. Ultimately, I contribute early empirical evidence of the effects that VR may have on our philosophical understanding.Computer Scienc
Diet Sustainability: A Global Investigation in Using Diet to Inform Food System Sustainability.
No full textSustainable Development Goal #2 (SDG 2, Zero Hunger) was created to end hunger, achieve food security, improve nutrition, and promote sustainable agriculture by 2030; however, it is projected that 600 million people will remain hungry by 2030 based on current dietary and food insecurity trends (UNSTATS, 2022; UNSTATS, 2023). The Food and Agricultural Organization (FAO) of the United Nations defines a sustainable diet as a diet that is nutritionally adequate, affordable & accessible, and agriculturally sustainable, which is thereby both healthy for humans and protective of the environment (FAO, 2010). However, there is a lack of evidence to show that a healthy diet is broadly associated with a healthy environment, and significant gaps in data are stated by the FAO as a challenge to accurately reflect progress towards achieving the SDGs (FAO, 2023b; Tilman & Clark, 2014).
Therefore, this study combined country-wide datasets published by the FAO and Global Dietary Database with the objectives to: 1) determine how metrics of nutritional adequacy, affordability and accessibility, and agricultural sustainability can be indicative of diet sustainability; 2) utilize pre-existing databases to identify gaps in progress towards SDG2 which contribute to high levels of undernourishment; 3) evaluate unique relationships between nutritional adequacy, affordability and accessibility, and agricultural sustainability across different regions globally; and 4) demonstrate the use of simplified and easily adoptable metrics which use currently available data for accurately informing regional food-system related policy.
In line with these objectives, I defined three metrics of a sustainable diet for 143 countries using recent peer-reviewed methods for nutritional adequacy, the cost of healthy foods, and regenerative agriculture. The relationships between the three metrics were evaluated by Pearson’s correlation coefficient and linear regression analysis to determine how each metric is related in the context of a sustainable diet. These metrics were further combined into one overall sustainable diet index to determine whether this combination can accurately reflect the state of diet sustainability with respect to the prevalence of undernourishment and the goals of SDG 2.
The results of this study support previous findings that a healthier diet is not always indicative of a healthier environment, as the metrics of nutritional adequacy and regenerative agriculture did not have a significant linear relationship (Tilman and Clark, 2014). However, when broken down by income-classification, defined by the World Bank, countries in the highest and lowest income groups were found to have opposite significant linear relationships with respect to nutritional adequacy and the cost of healthy foods. This study further revealed significant room for improvement in the calculation of metrics for nutritional adequacy, as low-income countries, which on average had the highest score for nutritional adequacy, were also observed to have the highest prevalences of undernourishment.
In conclusion, the overall sustainable diet index served as a useful tool as a broader indicator of diet sustainability; however, the balance and contributions of each metric to the overall index were found to be where the important implications lie for accurately informing sustainable food system policy.Extension Studie
Courage to Lead in the City Schools of Decatur: Leveraging Psychological Safety to Identify Opportunities for Learning
No full textThe City Schools of Decatur (CSD), located six miles northeast of Atlanta, Georgia, is a high-performing school district. At first glance, high student achievement results are evidence of outstanding teaching and learning for all students within the school district. However, when achievement data is disaggregated, a different narrative unfolds.
The achievement data for CSD students who identify as Black is far lower than that of their White counterparts. Some student groups have historically been underserved because educators have not provided them with the tools they need to learn and grow. This has been a matter of fact in CSD for decades. Upon the arrival of a new superintendent in the Spring of 2023, it was time for CSD to find the courage for growth and change.
Research shows that school principals have the wherewithal to facilitate change in favor of improved student outcomes. CSD school leaders have the potential to serve all students with support structures in place. As such, tracking and facilitating support could lead to a new CSD narrative. The district and school leadership could become the mobilizers of educational equity, ensuring all students are served according to their learning needs.
Surfacing the courage to lead in CSD required a three-pronged strategic approach that served as the basis for this capstone project. All three prongs leveraged school principals as the agent of change in schools. The first prong focused on facilitating canvas walkthroughs for principals to receive instructional feedback from district leadership. The second prong involved the creation of a school leader playbook that clarified the expectations and district supports that sought to ignite courage in CSD school leaders–courage so they may be true vanguards of data-driven instruction and educational equity. The third prong leveraged school support visits and the strategy that comes with an instructional cabinet support tracker. When the district leadership acts in the spirit of true collaboration, support to principals is stronger and more effective. The canvas walkthroughs, school leader playbook, and instructional cabinet support tracker led to changes in adult behavior that impacted teaching and learning in the classroom and to positive achievement results.Educatio
Succinct Verification Through Reed-Solomon and Folded Reed-Solomon Codes
No full textThe overarching problem for our thesis talks is succinct verification: how can one check that a computation (e.g. ) has been performed correctly? A natural way to verify is to repeat the claimed computation from scratch and check that the results agree. However, repeating computations from scratch can be very expensive, especially when the computation is not as simple as the given example. Given a computation that takes time naively, can we instead produce a proof that can be checked reasonably accurately in time sublinear in , such as ? In the 1990s, researchers studied probabilistically checkable proofs (PCPs) that solved the above problem. Informally, the PCP theorem (ALMSS, 1992) stated that there exists a proof format that allows a grader to read 3 words in a proof and still successfully grade the proof as correct or incorrect with high probability. The tradeoff in accuracy in exchange for succinct verifiability is called soundness. Such initial proof formats produced implausibly long proofs (despite being quick to verify), so some recent research has focused on making proof systems that are not only succinctly verifiable but also concretely efficient. Their primary real-world application today is making cryptocurrencies more scalable – networks like Ethereum are currently limited in their throughput due to it being time and energy intensive to verify transactions. However, such proof systems involve many beautiful mathematical tools as well. They reduce the verification step to a math problem called Reed-Solomon proximity testing (RPT): discerning whether a polynomial is low degree or far from a low-degree polynomial for some notion of ``farness".
One algorithm used to solve RPT in succinct verification systems is the Fast Reed-Solomon IOPP (FRI). The first few chapters of this thesis are expository sections introducing succinct verification and how succinct verification is connected to mathematical objects called error-correcting codes (ECCs). These sections build up to an explanation of FRI and its soundness.
We then explain a related ECC called Folded Reed-Solomon codes have a property called list decodable up to capacity. Informally, this means that such codes can tolerate a large number of errors while still being able to output a small list of candidate code words. FRI can solve RPT, but its soundness depends on the list-decoding size of Reed-Solomon codes, which is not known to achieve list-decoding capacity. Folded Reed-Solomon codes do achieve capacity when instantiated with the right parameters.
In the final part of this thesis, we propose modifications to FRI that can solve proximity testing for Folded Reed-Solomon codes.Computer Scienc
Raspberry-colloid-templated catalysts as a model thermocatalytic platform
No full textNanoparticle (NP)-supported catalysts are critical to the industrial production of over 90% of the chemicals and raw materials used today. Their catalytic performance is predicated on a combination of geometric and electronic descriptors associated with the properties of the NPs, support, and the (NP–support) interactions between them. However, existing catalyst preparative methods of nucleating and/or immobilizing NPs on support surfaces do not permit independent variation of NP or support properties as NP nucleation and growth characteristics are dependent on the support chemistry and vice versa. Consequently, such interconnected material properties cannot enable systematic investigations whereby individual NP or support properties are independently tuned to elucidate unambiguous and valuable structure–property relationships to guide future catalyst designs. Separately, this challenge is also exacerbated under thermocatalytic reaction conditions of high temperature, pressure, and mechanical agitation, which accelerates NP sintering and uncontrolled NP size growth, further confounding catalytic analyses. An effective model catalytic platform for fundamental structure–property studies should thus possess two pre-requisites: independent tunability of structural properties (NP and support) and high thermomechanical stability to preserve these as-synthesized structural properties under typical reaction conditions.
To address this gap, I adapted the raspberry-colloid-templating (RCT) strategy previously developed by the Aizenberg group. In Chapter 1, I outline the RCT synthetic methodology and highlight two key design features: partial NP entrenchment into the support which confers enhanced catalytic stability against NP sintering, and synthetic modularity for independent combinatorial variations of the catalyst’s building blocks and their spatial organization from the nanoscale to macroscale. These two unique features yield thermomechanically stable RCT catalysts with numerous degrees of freedom to isolate and independently tune potential catalytic descriptors, thereby facilitating unambiguous studies to derive newfound structure–property relationships that guide future catalyst designs.
In the rest of this dissertation, I describe how I leveraged on these two key design features to employ the RCT strategy as a well-defined and synthetically robust model thermocatalytic platform to elucidate important structural insights into catalyst design that cannot be easily achieved using traditional catalyst preparation methods. Specifically, I highlight my investigations into three structural features found in practically all NP-supported catalysts: properties of NP ensembles as a collective entity, NP–support interfaces, and individual NP properties. First, I demonstrate how using pre-formed colloidal NPs, in combination with the synthetic decoupling of the NP and support formation steps in the RCT method, disentangle the effects of NP proximity (Chapter 2), a collective NP ensemble property, from the effects of NP size (Chapter 3), to independently tune catalytic activity and selectivity, respectively. Second, I illustrate how the support chemistry and NP embedding effects can be deconvoluted to accentuate catalytic contributions arising from NP–support interfacial sites (Chapter 4), while also revealing nanoscale wetting phenomena at the interface that I subsequently exploited to direct bimetallic catalyst synthesis (Chapter 5). Third, I show how the RCT method can be applied to isolate individual NP properties from (all) other potential structural descriptors to facilitate systematic evaluations into individual NPs properties. This point is exemplified through separate studies into nanoscale effects of the surface Pd ensemble sizes in dilute Pd-in-Au alloyed NPs on competitive reactant adsorption energetics (Chapter 6), and distinguishing the surface- and vapor-mediated sintering pathways of Pt and Pd diesel oxidation catalysts (Chapter 7). Finally, I summarize my work, provide an outlook on the RCT catalyst platform, and discuss future opportunities, challenges, and applications (Chapter 8).Chemistry and Chemical Biolog
Essays on Early Education and Care Systems and Processes
No full textIn the three papers of this dissertation, I use data from a large study conducted in Massachusetts and regression-based approaches to analyze both access and quality in diverse early education and care (EEC) settings serving preschool-age children. In each of the papers, I include a broader range of EEC setting types than is common in prior literature (i.e., community center, Head Start, licensed family child care, and public school settings) and select measurement approaches that complement and extend those used in previous work, opening new avenues for understanding children’s opportunities and development in the context of EEC systems and settings.
In the first paper, I focus on a key component of EEC access: the availability of EEC near young children’s residences. I examine variation in EEC availability by neighborhood characteristics and explore the consequences of those patterns for families’ use of EEC. I find that young children residing in less densely populated areas and in areas with moderate socioeconomic opportunity tend to have less EEC available nearby than those living in other areas. I also find that, among families who selected group EEC for their children, children with more limited availability near their residences tend to have longer commutes to their providers.
The second and third papers of the dissertation consider the quality of the EEC settings children attend. In the second paper, I explore children’s multifaceted skill development during the kindergarten transition and the intersection between their skill development and prekindergarten process quality. I first examine child-level dynamics in skill development, analyzing cross-domain associations between children’s prekindergarten skills and their residual skill gains from prekindergarten to kindergarten in five areas: social competence, self-regulation, language, early math, and early reading. I find that children’s self-regulation, language, and early math skills are interconnected from prekindergarten to kindergarten, whereas children’s social and early reading skills are largely unassociated with the other assessed domains. I then turn to the setting level, analyzing associations between a fine-grained observational measure of prekindergarten process quality and children’s residual skill gains in the same five areas. I find few links between process quality and children’s later skills.
In the third paper, I explore a hypothesized predictor of process quality: early educator burnout. I first validate the internal structure of a widely used burnout measure in a sample of early educators working in a range of EEC setting types. I then use the measure to describe burnout levels among early educators, finding that burnout symptoms are on average infrequent. Finally, I examine associations between educator burnout and process quality in EEC settings and find few links.Educatio