Essays on Generational Economic Links Between Childhood and Adulthood

My dissertation examines the economic links between people's experiences in early and later-life. It offers new empirical evidence on the effect of income in infancy on later-life outcomes, and investigates the performance and econometric properties of the linking tools often used to create data for these long-term empirical investigations. In my first chapter, I estimate a relationship between family income in infancy and later-life outcomes for children. Eligibility for child-related tax benefits depends on the calendar year in which a child is born. Families with children born in December are eligible for tax benefits a year earlier than families with children born a few days later in January. These differences create a discontinuity in after-tax income in infancy worth on average approximately $2,000 for families in tax year 2016. I use regression discontinuity techniques to calculate the effect of this change in after-tax income on outcomes for children and young adults in Census data. Evidence show that a$1,000 increase in after-tax income in infancy results in a 1.2 percentage point increase in the probability of a student being grade-for-age by high school, a basic indicator of academic achievement and social maturity. Effects of this income shock are larger for children from families that are more likely disadvantaged at a child's birth, including Black families, and families with low education attainment. After high school, small differences in labor force attachment, earnings and education attainment persist for the adults who experienced the income increase as children. These effects are again pronounced for Black adults and adults born in counties with low average education attainment. In my second and third chapters, I investigate methodological problems that arise when linking data. Linking is often necessary to investigate generational economic links between childhood and adulthood. In the second chapter, my coauthors Martha Bailey, Catherine Massey, Morgan Henderson and I review the literature in historical record linkage in the U.S., and examine the performance of widely-used automated record linking algorithms. Focusing on algorithms in current practice, our findings highlight the important effects of linking methods on data quality. We then extend our analysis to look at the consequences of these differences in data quality on inference by computing intergenerational income elasticities between fathers and sons. Many of the methods produce estimated elasticities that are statistically distinguishable from the estimated intergenerational elasticity with hand-linked data, suggesting that the linking algorithms themselves may bias inference. However, eliminating false matches renders elasticity estimates similar to each other, and statistically indistinguishable from the elasticity estimated with the hand-linked data. In the third chapter, my coauthors Martha Bailey, Catherine Massey and I investigate two complementary strategies to address the issues we highlight in my second chapter. We investigate the use of validation variables to identify higher quality links and a regression-based weighting procedure to increase the representativeness of custom research samples. We demonstrate the potential value of these strategies using the 1850-1930 Integrated Public Use Microdata Series Linked Representative Samples (IPUMS-LRS). We show that, while incorrect linking rates appear low in the IPUMS-LRS, researchers can reduce error rates further using validation variables. We also show researchers can reweight linked samples to balance observed characteristics in the linked sample with those in a reference population using a simple regression-based procedure.PHDEconomicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/169801/1/colecp_1.pd

Deciphering the Contribution of BP230 Autoantibodies in Bullous Pemphigoid.

Bullous pemphigoid (BP) is a subepidermal autoimmune blistering disease predominantly affecting elderly patients and carries significant morbidity and mortality. Patients typically suffer from severe itch with eczematous lesions, urticarial plaques, and/or tense blisters. BP is characterized by the presence of circulating autoantibodies against two components of the hemidesmosome, BP180 and BP230. The transmembrane BP180, also known as type XVII collagen or BPAG2, represents the primary pathogenic autoantigen in BP, whereas the intracellular BP230 autoantigen is thought to play a minor role in disease pathogenesis. Although experimental data exist suggesting that anti-BP230 antibodies are secondarily formed following initial tissue damage mediated by antibodies targeting extracellular antigenic regions of BP180, there is emerging evidence that anti-BP230 IgG autoantibodies alone directly contribute to tissue damage. It has been further claimed that a subset of patients has a milder variant of BP driven solely by anti-BP230 autoantibodies. Furthermore, the presence of anti-BP230 autoantibodies might correlate with distinct clinical features. This review summarizes the current understanding of the role of BP230 and anti-BP230 antibodies in BP pathogenesis

Insights Into the Pathogenesis of Bullous Pemphigoid: The Role of Complement-Independent Mechanisms.

Bullous pemphigoid is an autoimmune blistering disease caused by autoantibodies targeting BP180 and BP230. While deposits of IgG and/or complement along the epidermal basement membrane are typically seen suggesting complement -mediated pathogenesis, several recent lines of evidence point towards complement-independent pathways contributing to tissue damage and subepidermal blister formation. Notable pathways include macropinocytosis of IgG-BP180 complexes resulting in depletion of cellular BP180, direct induction of pro-inflammatory cytokines from keratinocytes, as well as IgE autoantibody- and eosinophil-mediated effects. We review these mechanisms which open new perspectives on novel targeted treatment modalities

Static Degradation of Electrospun Polycaprolactone Scaffolds

Static Degradation of Electrospun Polycaprolactone Scaffolds Emily Clement, Depts. of Biomedical Engineering and Electrical Engineering, Connor Donlan, Sam Cole, Sarah K. Saunders, and Johana Bracamonte, with Dr. Joao Soares, Dept. of Mechanical Engineering Introduction: Engineered tissue vascular grafts (ETVGs), composed of cells seeded on a biodegradable scaffold, can be used to replace non-functional blood vessels. The scaffold acts as a replacement for the extracellular matrix, providing structural support to the developing tissue. A common biodegradable scaffold material is polycaprolactone (PCL). The main degradation mechanism of PCL is hydrolysis, which can be catalyzed by the use of NaOH solutions. Acceleration techniques must be employed to obtain information about the degradation in shorter observation times. In this study, we will compare the effect of degradation on physical and mechanical properties from samples degraded in PBS solutions (that mimics the pH of biological environments), and alkaline NaOH solutions. We hypothesize that the accelerated degradation profiles can be correlated to degradation profiles under in vivo like conditions. Methods: This study focuses on PCL (PCL 80,000 g/mol) 3mm electrospun scaffolds. Accelerated conditions were produced by submerging the scaffolds in increased NaOH solutions. The weight loss, elastic modulus, and microstructure of the scaffolds were assessed after vacuum drying at 0, 7, 14, 21, and 42 days. Phosphate-buffered saline (PBS) solution was used to replicate physiological-like pH conditions. This group was tested for elastic modulus, weight loss, and thickness at 0, 3, and 6 months. Results: The rate of change in mass, fiber orientation, and mechanical stiffness increased as the alkalinity of the liquid media increased to pH 12.45. Changes in the mechanical properties of the scaffolds became noticeable after 3 weeks of degradation. A decrease in mass stiffness was observed following a steep decrease in mass. At 6 weeks of degradation, the samples experienced a 20% decrease from the original mass and a 50% drop in membrane stiffness. The scaffolds swelled shortly after degradation began, but the swelling decreased as the mass decreased. In the non-accelerated degradation group, the scaffolds exhibited an average mass loss of 10 +/- 7% with no significant changes to mechanical properties. The scaffold thickness swelled to 40 +/- 20%, aligning with our previous works that showed scaffold swelling decreases at a larger pH. Conclusions: If the degradation of PCL scaffolds in physiological pH conditions follows the same trend as those in accelerated conditions, a stage of pronounced decrease in mass will be accompanied by a significant decrease in membrane stiffness and porosity. We hypothesize that the accelerated and non-accelerated degradation profiles are equivalent, meaning accelerated degradation can be used as a base to predict a scaffold’s behavior in physiological conditions.https://scholarscompass.vcu.edu/uresposters/1358/thumbnail.jp

Precision Doppler Shift Measurements with a Frequency Comb Calibrated Laser Heterodyne Radiometer

We report precision atmospheric spectroscopy of $CO_2$ using a laser heterodyne radiometer (LHR) calibrated with an optical frequency comb. Using the comb-calibrated LHR, we record spectra of atmospheric $CO_2$ near 1572.33 nm with a spectral resolution of 200 MHz using sunlight as a light source. The measured $CO_2$ spectra exhibit frequency shifts by approximately 11 MHz over the course of the five-hour measurement, and we show that these shifts are caused by Doppler effects due to wind along the spectrometer line of sight. The measured frequency shifts are in excellent agreement with an atmospheric model, and we show that our measurements track the wind-induced Doppler shifts with a relative frequency precision of 100 kHz (15 cm/s), equivalent to a fractional precision of a few parts in $10^{10}$. These results demonstrate that frequency-comb-calibrated LHR enables precision velocimetry that can be of use in applications ranging from climate science to astronomy.Comment: 4 pages, 3 figure

UC-502 Chess App with AI

The objective of this project is to create a website that contains a virtual chess game, where the user can play against an opponent powered by an artificial intelligence model. This chess platform will be a widely accessible and user-friendly way to become more familiar with and practice the game of chess

Concert recording 2018-02-18

[Track 1]. Cavatina Largo al factotum / Gioachino Rossini -- [Track 2]. Duettino / Eugene Bozza -- [Track 3]. Romance de barrio / Anibal Troilo arranged by Gonzalo Brusco -- [Track 4]. Danny boy / Traditional arranged by Ian McCubbin -- [Track 5]. Malevos / Noelia Escalzo -- [Track 6]. Muppets theme / Jim Henson Sam Pottle

Direct Kerr-frequency-comb atomic spectroscopy

Microresonator-based soliton frequency combs - microcombs - have recently emerged to offer low-noise, photonic-chip sources for optical measurements. Owing to nonlinear-optical physics, microcombs can be built with various materials and tuned or stabilized with a consistent framework. Some applications require phase stabilization, including optical-frequency synthesis and measurements, optical-frequency division, and optical clocks. Partially stabilized microcombs can also benefit applications, such as oscillators, ranging, dual-comb spectroscopy, wavelength calibration, and optical communications. Broad optical bandwidth, brightness, coherence, and frequency stability have made frequency-comb sources important for studying comb-matter interactions with atoms and molecules. Here, we explore direct microcomb atomic spectroscopy, utilizing a cascaded, two-photon 1529-nm atomic transition of rubidium. Both the microcomb and the atomic vapor are implemented with planar fabrication techniques to support integration. By fine and simultaneous control of the repetition rate and carrier-envelope-offset frequency of the soliton microcomb, we obtain direct sub-Doppler and hyperfine spectroscopy of the $4^2D_{5/2}$ manifold. Moreover, the entire set of microcomb modes are stabilized to this atomic transition, yielding absolute optical-frequency fluctuations of the microcomb at the kilohertz-level over a few seconds and < 1 MHz day-to-day accuracy. Our work demonstrates atomic spectroscopy with microcombs and provides a rubidium-stabilized microcomb laser source, operating across the 1550 nm band for sensing, dimensional metrology, and communication.Comment: 5 pages, 3 figure

Junior Recital: Connor Osburn, horn

This recital is presented in partial fulfillment of requirements for the degree Bachelor of Music in Performance. Mr. Osburn studies horn with Tom Witte.https://digitalcommons.kennesaw.edu/musicprograms/1306/thumbnail.jp