VictorJuiz/thesis huggingface dataset:
Effects of Earlier Special Education Placement on Pre-Literacy and Literacy Skills Development

The study estimates the impact of earlier special education placement on a number of preliteracy skills and independent reading level over the course of the academic year. Specifically, it examines differences between students placed in special education during transitional kindergarten (TK) (N=233) or kindergarten (N=1,769) against students placed in special education after TK (N=76) or kindergarten (N=1,116). Weights from entropy balancing with age, race/ethnicity, English language proficiency, gender, percent-free or reduced lunch (school-level), and kindergarten cohort year are used to create a best possible comparison group, and the outcomes of interest are from San Francisco Unified School District’s Fountas and Pinnell 2015-2016 to 2021-2022 test score data. The findings are that there is no significant effect of earlier placement on the preliteracy composite score, but earlier-placed students perform a bit better on letter recognition and letter sounds but worse on initial syllables, blending, rhyming, and early literacy behaviors (though, the degree of significance differs by skill, sample, and testing window). Additionally, there is a significant positive effect size of earlier placement on independent reading level – this difference becomes significant in kindergarten spring and grows over the course of the first-grade year.

Keywords: Education
Special education
Literacy
Literacy > Study and teaching (Early childhood)
Early childhood education
Text
Thesis
Advisor: Lemons Chris
The effects of relatedness and sex-biased demographic processes on human genetic variation

Many evolutionary processes affect human genetic variation. One of these processes, consanguinity (mating between closely related individuals) increases the frequency at which identical genomic segments are inherited along separate paths of descent. This pairing of segments increases the fraction of the genome that is shared within or between individuals: the fraction that lies in runs of homozygosity (ROH) or that contains identical-by-descent (IBD) segments. Consanguinity is relatively common globally, with couples who are second cousins (or closer) as well as their offspring perhaps representing an estimated 10% of the human population. The types and degree of consanguinity vary widely across cultures and affect patterns of shared segments. This variation provides an opportunity to study how a cultural practice such as consanguinity can influence patterns of genetic variation that are observed in the genome. Genomic sharing, both within and between individuals in a population, can be studied by noting that ROH and IBD at a genomic site are inversely proportional to its coalescence time: the time at which a pair of copies of the site find a common ancestor. First-cousin consanguinity can take one of four forms differing in the configuration of sexes in the pedigree of the male and female cousins who join in a consanguineous union: patrilateral parallel, patrilateral cross, matrilateral parallel, and matrilateral cross. Because of the different configurations of sexes in the pedigree, these four types of first-cousin consanguinity, which are equivalent in their effects on the autosomes, are expected to have differing effects on coalescence times (and therefore ROH and IBD) on the X chromosome. Over several chapters, this dissertation models each of these types of consanguinity to study the effect that each has on X-chromosomal genomic sharing relative to autosomal genomic sharing.

Keywords: Medicine.
Genetics.
Advisor: Rosenberg Noah
Montgomery Stephen
Pritchard Jonathan
Tang Hua
Effects of the Affordable Care Act Medicaid Expansion on Youth Mental Health: Findings from the Youth Risk Behavior Surveillance System, 2009-2019

I investigate the effects of the Affordable Care Act's Medicaid Expansion on the mental health of high school students using data from the Youth Risk Behavior Surveillance System from 2009 to 2019. I find that Medicaid Expansion was associated with decreases in rates of suicidal ideation and suicide attempts. Following Medicaid Expansion, youth residing in Expansion states experienced a 0.73 percentage point decline in suicidal ideation and a 0.68 percentage point decline in suicide attempts, a 4.88% and 4.80% reduction over the pre-treatment mean in Expansion states, respectively; these effects are marginally significant at the 10% level. The effects of Medicaid Expansion against suicidality appear five years post-policy implementation for both suicidal ideation and suicide attempts, which is 2019 for most of the Expansion states. Analyzing the effects of Medicaid Expansion by demographic subgroups suggest that the policy may have particularly benefited Black and queer youth who experienced increases in the prevalence of self-reported major depressive episodes but decreases in suicidal behavior.

Keywords: Medicaid Expansion
Affordable Care Act
youth mental health
suicidality
Text
Thesis
Advisor: Rossin-Slater Maya
Efficient deep reinforcement learning for recommender systems

Current recommender systems predominantly employ supervised learning algorithms, which often fail to optimize for long-term user engagement. This short-sighted approach highlights the significance of sequential recommender systems, designed to make decisions that extend beyond immediate user responses. To maximize cumulative positive feedback, these systems must balance exploration—probing users for insightful feedback to inform future recommendations—and the strategic selection of items that pave the way for more successful future interactions. However, the dynamic nature of user behavior and evolving social trends present additional challenges, demanding that sequential recommender systems operate effectively in non-stationary environments. This necessitates a more discerning exploration strategy, focusing on gathering enduring insights rather than ephemeral information. In this dissertation, I introduce three key advancements in sequential recommender systems. These contributions are centered around scalable and intelligent exploration techniques, accommodating both immediate and delayed user feedback, while adeptly adjusting to non-stationary contexts. I provide both theoretical and empirical evidence demonstrating that our proposed algorithms outperform existing benchmarks in computational efficiency and in generating higher empirical cumulative user feedback.

Keywords: Engineering.
Management Science and Engineering.
Advisor: Van Roy Benjamin
Sadigh Dorsa
Ye Yinyu
Efficient greenfield mineral exploration

A growing population will require more metal in order to sustainably build a high quality of life. However, there have been fewer discoveries of mineral deposits due to constrained exploration budgets and confounding geology. There are few practical tools for decision-support in greenfield mineral exploration. This dissertation focuses on developing and testing methods for increasing the efficiency of mineral exploration, with a focus on optimal planning of boreholes. The global context of mineral supply and an overview for mineral exploration is provided in Chapter 1. The necessary elements for modelling decision-making problems are defined and formulations are explained in the context of mineral exploration. Reward functions such as those based on hypothesis falsification or efficacy of information are demonstrated on illustrative cases. High dimensional optimization problems, such as those in the subsurface, are oftentimes intractable. To address this issue, approximations are introduced and demonstrated. Chapter 3 presents a decision-making problem on a real case in Western Australia, formulated as a partially-observable Markov decision process (POMDP) and solved using Monte Carlo tree search (MCTS) with a belief-based reward function. Belief-based rewards are demonstrated to be more performant than the state-of-the-art solvers, and a sensitivity analysis of performance to the belief-based reward is performed. Furthermore, a sensitivity analysis of the optimal plan to a decision-maker's input preference demonstrates how the optimal first decision changes based on a volume threshold. Chapter 4 formulates greenfield exploration drilling using sequential value-of-information, and shows that the selection of a first borehole changes if the decision-maker directly encodes the option of continuing to a second borehole. Discussion of future research directions conclude the dissertation.

Keywords: Sustainability.
Geological Sciences.
Advisor: Caers Jef
Kochenderfer Mykel J.
Mukerji Tapan
Efficient platform for 3D and full optical field imaging

Optical imaging plays an important role as the perceptual eyes of machines. In contrast to conventional two-dimensional intensity imaging, such as photography, probing the additional dimensions within the optical field is challenging. The demand for fast, data-efficient, and accurate imaging systems and signal-processing pipelines is raising great interest in both academia and industry. This dissertation introduces our contributions toward enhancing the robustness and efficiency of 3D and full optical field imaging systems. Firstly, we discuss time-of-flight-based 3D imaging. We introduce novel scanning trajectory designs and control systems for resonant Micro-electro-mechanical (MEMS) optical scanners operating at >100Hz frame rate. We also introduce post-processing algorithms that harness sensor fusion and temporal fusion to reconstruct clean and high-resolution 3D structures from noisy, low-resolution raw data, thus enhancing the quality and utility of 3D imaging in broad applications. Secondly, we introduce our research in photonics integrated circuit (PIC)-based full optical field imaging. Here, we propose the design of optical phase sensor arrays and the corresponding post-processing algorithm. These components enable the precise measurement of the optical phase within a single measurement step without external references or spatial light modulators. By measuring relative phases across both neighboring and distant spatial locations, we achieve scalability and robustness against hardware errors and noise. We also design PIC for high-contrast optical mode decomposition and filtering. By leveraging redundant elements at both the device and architecture levels, we successfully extract weak optical signals that would otherwise be overwhelmed by background light intensities exceeding 100000 times stronger. These systems provide significant benefits for applications including bio-imaging, remote sensing, and astro-imaging.

Keywords: Engineering.
Electrical Engineering.
Advisor: Solgaard Olav
Miller D. A. B.
Wetzstein Gordon
Efficient Remuneration of Power-5 College Football Players

A growing body of literature attempts to estimate the economic impacts of the NCAA’s monopsony power in the labor market for college athletes in the revenue-generating sports of football and, to a lesser extent, men’s basketball. This literature is becoming increasingly pertinent as pending legislative and judicial action threatens to disrupt the NCAA’s ability to suppress wages to zero. This paper expands on past empirical research using the most comprehensive set of Power-5 college football recruiting, performance, and finance data ever compiled to first replicate two prior models estimating the marginal revenue products of players. That dataset is then used to execute a two-stage revenue-above-replacement model utilizing marginal revenue product estimations derived from a direct performance measure and position categorizations. We find significant variation in revenue-above-replacement figures between performance level and position, with a top percentile quarterback generating nearly $600k above a walk-on replacement player. We produce a matrix reporting revenue-above-replacement figures by position and percentile of performance, and make recommendations for AB 252, a bill currently moving through the California State Legislature which seeks to mandate remuneration of college athletes in revenue-generating sports.

Keywords: Public Policy Program
College Football
College Athletics
NCAA
Student-Athletes
College Athletes
College sports > Economic aspects
Sports Economics
Marginal Revenue Product
Stanford University
Humanities and Sciences
Public Policy Program
Text
Thesis
Advisor: Noll Roger
Elastic energy-recycling actuators for efficient robotics

Actuator power consumption is a limiting factor in mobile robot design. Despite improvements in efficient design, motors still waste a significant portion of battery energy as heat, limiting what can be done on a single battery charge. Simple mechanical springs can convert between stored elastic energy and work with high efficiency and passively produce torque without thermal losses, yet they afford none of the control and versatility offered by electric motors. We introduce an elastic 'energy-recycling' actuator that leverages the efficiency of mechanical springs to perform repetitive tasks with less electrical energy via controlled capture and return of elastic energy. The prototype actuator comprises a motor in parallel with an array of springs that can be individually engaged and disengaged, without losing stored energy. Springs are controlled by pairs electroadhesive clutches, allowing high-bandwidth (12 Hz) control of passive torque production (> 6 Nm) with low power consumption (< 0.4 W). We developed a position tracking controller for the actuator and tested it in five repetitive tasks with features that occur frequently in actuation but are difficult to perform efficiently. The actuator reduced power consumption by at least 50% in all cases and by 97% in the best case. Elastic energy recovery, controlled by low-power clutches, can improve the efficiency of mobile robots, assistive devices, and many other engineered systems.

Keywords: Engineering.
Mechanical Engineering.
Advisor: Collins Steve
Cutkosky Mark
Schwager Mac
Electric-field induced nonlinear optics in CMOS silicon nanophotonic waveguides

The microelectronics industry is foundationally built on silicon-based semiconductor devices. Silicon photonics, a relatively nascent yet rapidly emerging field, leverages the maturity of CMOS foundry processes and promises dense integration of optical functionality like that of microelectronic circuits. However, silicon's inability to produce optical gain or lase has presented a major barrier to developing fully integrated silicon-based optoelectronic devices. In parallel, nonlinear optics has made substantial advances in expanding the range of accessible frequencies of optical sources, yet as a field has evolved largely independently of silicon-based materials. By combining the principles of nonlinear optics with scalable, high-quality linear optical elements enabled by silicon photonics, such as waveguides, and electronic devices, such as CMOS-based diodes, all on-chip, the latitude of optoelectronic functionality of silicon can be significantly expanded. Although nonlinear optical processes such as sum frequency generation and optical parametric amplification are forbidden in silicon, due to its crystalline inversion symmetry, this symmetry can be broken with an applied electric field, a process known as electric field induced second harmonic generation, which is effectively derived from the third-order susceptibility of a material and can be understood as four-wave mixing between two optical electromagnetic fields, one DC field, and a resultant optical field at a harmonic frequency. Moreover, quasi-phase matching allows for efficient power transfer between these fields, which can be implemented at-scale in silicon using periodically-poled DC fields generated by reverse-biased PN diodes. In this thesis, I will discuss the design and characterization of devices that utilize industry-ready silicon photonics foundry processes to realize nonlinear optics on-chip via second harmonic generation and the first (second-order) optical parametric amplifier on silicon

Keywords: Engineering.
Electrical Engineering.
Advisor: Mabuchi Hideo
Safavi-Naeini Amir H.
Solgaard Olav
Electrochemical transport in energy storage systems

Rechargeable lithium batteries are electrochemical devices widely used in portable electronics and electric-powered vehicles. A breakthrough in battery performance requires advancements in battery cell configurations at the microscale level. This, in turn, places a premium on the ability to accurately predict complex multiphase thermo-electrochemical phenomena, e.g., migration of ions interacting with composite porous materials that constitute a battery cell microstructure. Optimal design of porous cathodes requires efficient quantitative models of microscopic (pore-scale) electrochemical processes and their impact on battery performance. We derive effective properties (electrical conductivity, ionic diffusivity, reaction parameters) of a composite electrode comprising the active material coated with a mixture of the binder and conductor (the carbon binder domain or CBD). These effective descriptors ensure the conservation of mass and charge. When used to parameterize industry-standard pseudo-two-dimensional (P2D) models, they significantly improve the predictions of lithiation curves in the presence of CBD. We identified a P2D model that provides a middle ground between model complexity and prediction accuracy. On the lithium anode, dendritic growth is a leading cause of degradation and catastrophic failure of batteries with lithium anodes, e.g., lithium-metal batteries and all-solid-state lithium batteries. Deep understanding of this phenomenon would facilitate the design of strategies to reduce, or completely suppress, the instabilities characterizing electrodeposition on the lithium anode. We present linear stability analyses to quantify the interfacial instability associated with dendrite formation in terms of the battery's operating conditions and the electrochemical and physical properties of battery materials. This would improve the safety of lithium-metal batteries with liquid electrolyte and all-solid-state lithium batteries. When considered holistically, the quantitative nature of our work provides mechanistic insights into the optimal design of i) porous cathodes, ii) electrolytes, and iii) dendrite-suppressing buffers between the lithium-metal anode and electrolyte. The design of electrolytes involves the optimal selection of a solvent and salt, the tuning of the ionic concentration of the solution, and the deployment of anisotropic electrolytes (e.g., liquid crystals, liquid-crystalline physical gels, and the use of separators with anisotropic pore structures or columnized membranes)

Keywords: Sustainability.
Energy Resources Engineering.
Advisor: Tartakovsky Daniel
Tchelepi Hamdi
Chu Steven
Cui Yi
Electro-optic techniques for nanosecond imaging and applications to fluorescence lifetime microscopy

Fluorescence microscopy allows targeted visualization of biological matter across spatial and temporal scales. Most methods rely on measurements of image intensity that are taken with a standard camera sensor at low frame rates. The nanosecond excited state lifetime of a fluorescent probe also carries valuable information about the local environment which can be used to improve optical measurements, but it cannot be captured with common cameras. Current lifetime detectors are either too slow or too noisy for many applications. This thesis presents the development of nanosecond imaging optics and the electro-optic fluorescence lifetime imaging microscopy (EO-FLIM) method. Fast optical gating of a wide-field image is achieved using electro-optic crystals, allowing lifetimes to be measured on scientific camera sensors with high sensitivity. EO-FLIM improves photon throughput by several orders of magnitude over standard time-resolved detectors. Lifetime is estimated from a ratio of optical intensities, which increases the information content of the captured image while also rejecting intensity noise and motion artifacts. Several optical systems and technological improvements are presented which have enabled wide-field lifetime imaging of single fluorescent molecules, combination of lifetime imaging with super-resolution localization microscopy, and lifetime recording of neuron action potentials and sub-threshold voltage activity in vivo at kilohertz frame rates. Applications to light-sheet microscopy and time-of-flight imaging are also shown.

Keywords: Humanities and Sciences.
Applied Physics.
Advisor: Kasevich Mark
Moerner William
Schnitzer Mark
Electrostatic catalysis : a physical principle for designing faster enzymes

Enzymes are proficient biocatalysts arising from billions of years of evolution. Understanding the fundamental principles of how enzymes achieve such remarkable rate accelerations may facilitate the rational design of efficient artificial enzymes and small-molecule catalysts, which remains a grand challenge despite decades-long effort. Through extensive structural studies such as x-ray crystallography, it has been well recognized that a key to enzyme catalysis is a pre-organized active site, where the chemical transformation occurs; however, the energetic basis that links active-site structures to their catalytic power remains much debated, which, in part, impedes the progress of enzyme and catalyst design. Building upon the previous studies, this dissertation is focused on characterizing the unique electrostatic environment in an enzyme's active site and revealing its functional importance in enzyme catalysis. The results presented in this work suggest a general design principle of catalysts with a focus on the electric field, an underexplored element that is powerful for enhancing reaction rates

Keywords: Humanities and Sciences.
Chemistry.
Advisor: Boxer Steven G. (Steven George)
Fayer Michael D.
Stack T. (T. Daniel P.)