Three Essays on Public Policy: Physician Labor Supply, Food Insecurity, and Income Inequality

This dissertation comprises three papers on physician labor supply, food insecurity, and income inequality. My research broadly explores how public policies and government programs affect individual behavior and how effectively they alleviate inequality and poverty. Chapter 1 estimates the impact of a transitory reduction in hours during physicians’ early career on their long-term labor supply. I exploit the work-hour regulations that limit the maximum workweek by residents as the source of exogenous variation. The results show that exposure to the regulations significantly decreases practicing physicians’ labor supply by about four hours per week on average, with female physicians being more responsive to a given reduction in early career hours. Distributional results using a changes-in-changes model confirm that the regulations primarily affect the upper end of the work hours distribution. To reveal potential mechanisms of these effects, I find that the reform increases the probabilities of marriage and having a child, as well as the total number of children, for female physicians. In contrast, it does not have a significant impact on marriage and fertility outcomes for male physicians. These findings provide a better understanding of physicians’ hours of work in response to the reform over time and the role of gender with respect to labor supply behavior and family formation decisions. Chapter 2 studies the role of government programs in alleviating differential exposure to food insecurity. We provide a framework that conceptualizes how the Supplemental Nutrition Assistance Program (SNAP) could have differences in benefit levels across racial/ethnic groups. We decompose differences in SNAP benefit levels into three components: differences in eligibility, participation, and generosity. We then link the results to differences in food consumption to provide implications on food insecurity differentials. Our results reveal that SNAP has different pathways to reducing food insecurity for different populations. Among the three components, eligibility contributes the most to SNAP benefits for both blacks and Hispanics relative to whites. However, SNAP reduces differences in food consumption between blacks/Hispanics and whites by a modest amount, which is likely not enough to reduce the differences in the resource gaps between groups. We also provide an exploratory analysis of how changes to SNAP policy rules might affect differences in food insecurity across groups. Our results suggest that the automatic enrollment policy might be effective in ameliorating the disparities. Chapter 3 estimates the effects of trade liberalization on household income inequality and investigates whether trade liberalization or domestic reforms are the main influence factors of the rising inequality since 1980 in Taiwan, a middle-income open economy. We construct an empirical model by decomposing the sources of household disposable income in the quintile ratio. Using time-series data from 1980 to 2015 to estimate the long-run effect, we find that trade liberalization raises income inequality overall. When separating trade partners into OECD and non‐OECD countries, our results show that net exports to OECD countries increase inequality, whereas net exports to non-OECD countries insignificantly decrease inequality. Moreover, we provide evidence that domestic reforms, particularly technological progress in favor of skilled labor and industrial structural change, rather than trade liberalization, are the main driving forces of income inequality

Reflections on Skipping Stones to Diving Deep: The Process of Immersion as a Practice

Reflecting upon over 30 years of teaching courses with a community service-learning and engagement component, this article is a personal piece that explores the author’s journey through voluntarism, community service-learning and civic engagement, and how that path has led to embracing immersion as a critical pedagogical practice for community engagement

Drosophila arc Encodes a Novel Adherens Junction-Associated PDZ Domain Protein Required for Wing and Eye Development

AbstractLoss of arc function results in a downwardly curved wing and smaller eyes with a reduced number of ommatidia. Consistent with this phenotype, molecular analysis shows that arc mRNA and protein are expressed in the wing imaginal disc and in clusters of cells in the morphogenetic furrow of the eye imaginal disc. The 36-kb arc transcription unit contains 10 exons that are spliced to form a 5.5-kb mRNA. The encoded Arc protein is 143,000 Da and contains two PDZ (PSD-95, Discs large, ZO-1) domains; there is no close structural similarity to other PDZ proteins. In addition to its expression in imaginal discs, arc is expressed during embryogenesis in epithelia undergoing morphogenesis, including the invaginating posterior midgut, evaginating Malpighian tubule buds, elongating hindgut, invaginating salivary glands, intersegmental grooves, and developing tracheae. Arc protein colocalizes with Armadillo (β-catenin) to the apical (luminal) surface of these developing epithelia, indicating that it is associated with adherens junctions. Genes that are required for patterning of embryonic epithelia (e.g., tailless, Krüppel, fork head, and brachyenteron) or for progression of the morphogenetic furrow (i. e., hedgehog) are required to establish or maintain the regional expression of arc. Misexpression of arc in the eye imaginal discs results in rough and larger eyes with fused ommatidia. We propose that arc affects eye development by modulating adherens junctions of the developing ommatidium

TGF-beta signaling proteins and the Protein Ontology

The Protein Ontology (PRO) is designed as a formal and principled Open Biomedical Ontologies (OBO) Foundry ontology for proteins. The components of PRO extend from a classification of proteins on the basis of evolutionary relationships at the homeomorphic level to the representation of the multiple protein forms of a gene, including those resulting from alternative splicing, cleavage and/or posttranslational modifications. Focusing specifically on the TGF-beta signaling proteins, we describe the building, curation, usage and dissemination of PRO. PRO provides a framework for the formal representation of protein classes and protein forms in the OBO Foundry. It is designed to enable data retrieval and integration and machine reasoning at the molecular level of proteins, thereby facilitating cross-species comparisons, pathway analysis, disease modeling and the generation of new hypotheses

Co-optimizing High and Low Voltage Systems: Bi-Level vs. Single-Level Approach

This paper presents a bi-level optimization framework applied to optimize system performance with (i) increasing presence of distributed energy resources (DER) at the low-voltage level, and (ii) variable wind power generation at the high-voltage level. The paper investigates various system configurations with increasing presence of microgrids, with active devices. System simulations quantify system performance in terms of cost, first using the traditional single-level optimization framework, and second using the proposed bi-level framework. Comparisons between the system with traditional, passive distribution systems and with microgrids are also presented, with results again quantified via the interconnected system operating costs. Results show that at low levels of DER and microgrid penetration, traditional (single-level) system optimization algorithms perform adequately as compared to the proposed bi-level optimization framework. However, as DER and microgrid penetration increase, the traditional single-level framework does not accurately capture the full system benefits of distributed technologies. The results demonstrate that new optimization algorithms, such as the proposed bi-level framework, will be required if the benefits of DER are to be accurately quantified in the evolving power system

Smart Cards to Enhance Security and Privacy in Biometrics

Smart cards are portable secure devices designed to hold personal and service information for many kind of applications. Examples of the use of smart cards are cell phone user identification (e.g. GSM SIM card), banking cards (e.g. EMV credit/debit cards) or citizen cards. Smart cards and Biometrics can be used jointly in different kinds of scenarios. Being a secure portable device, smart cards can be used for storing securely biometric references (e.g. templates) of the cardholder, perform biometric operations such as the comparison of an external biometric sample with the on-card stored biometric reference, or even relate operations within the card to the correct execution and result of those biometric operations. In order to provide the reader of the book with an overview of this technology, this chapter provides a description of smart cards, from their origin till the current technology involved, focusing especially in the security services they provide. Once the technology and the security services are introduced, the chapter will detail how smart cards can be integrated in biometric systems, which will be summarized in four different strategies: Store-on-Card, On-Card Biometric Comparison, Work-sharing Mechanism, and System-on-Card. Also the way to evaluate the joint use of smart cards and Biometrics will be described; both at the performance level, as well as its security. Last, but not least, this chapter will illustrate the collaboration of both technologies by providing two examples of current major deployments.Publicad