3948 research outputs found
Sort by
Spatiotemporal Regulation of Cdc42 Activity Directs Specific Membrane Trafficking Events at Distinct Cell Sites:
Get PDFThesis advisor: Maitreyi E. DasPolarization allows cells to form and maintain morphologies necessary for their diverse functions during processes such as growth, division, differentiation, and migration. Signaling proteins such as the family of small Rho GTPases promote polarization by spatiotemporally regulating cytoskeleton dynamics and coordinating membrane trafficking. Here, we investigate and define roles of the Rho GTPase Cdc42 in promoting polarization in S. pombe. As fission yeast, S. pombe cells grow from their cell ends during interphase and divide by medial fission to produce two new daughter cells. As cell-walled organisms, growth and division require intricate remodeling and expansion of the cell wall via incorporation of new membrane and proteins at these polarized sites. Thus, growth and division require specific sequences of membrane trafficking events to deliver and remove cargo at appropriate times and locations. During cytokinesis, fission yeast cells divide by synthesizing new cell wall called the septum to medially bisect the cell. The septum is synthesized behind the actomyosin ring to aid its constriction. Once ring constriction completes and the septum matures, the septum is partially digested to physically separate the daughter cells. Previous work has shown that Cdc42 promotes the delivery of specific but not all septum-synthesizing enzymes as well as septum-digesting enzymes, but it was not known how Cdc42 activation is regulated at the division site to temporally coordinate these processes. Here, we show that the Cdc42 GAPs Rga4 and Rga6 promote proper septum synthesis and timely cell separation by locally decreasing Cdc42 activation during late cytokinesis. This work also reveals a role for Cdc42 in regulating clathrin-mediated endocytosis, both at the division site as well as at growing cell ends. To further explore this role, we systematically examined the behaviors of endocytic actin patches in mutants of Cdc42 regulators and compared these dynamics to wild-type controls. This characterization led to the observation that endocytic patches are best formed to induce successful patch internalization at sites of polarization where Cdc42 is active. In this work, we show that Cdc42 activation promotes proper endocytic patch behavior in a dose-dependent manner and that Cdc42 regulates endocytosis via its downstream effector, the Pak1 kinase. We also demonstrate that Cdc42 and Pak1 activity promote endocytosis through at least two pathways which regulate branched actin formation. First, we show that Cdc42 and Pak1 promote proper endocytic actin patch formation. Secondly, we show that Pak1-mediated phosphorylation of the endocytic Type I myosin promotes timely internalization of endocytic actin patches.Thesis (PhD) — Boston College, 2024.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Biology
Essays on Gender Differences in Job Search Beliefs and Behavior:
No full textThesis advisor: Lucas CoffmanGender Differences in Sorting on the Job Market: The Role of Application Costs Research shows that, holding qualifications equal, women are less willing than men to apply for certain high-paying jobs. Through a stylized labor market experiment, I investigate whether the "gender application gap" for high-paying jobs is affected by the presence or magnitude of application costs. I randomly vary the cost of applying for such a job, with subjects either facing no marginal cost, paying a fee, or writing a cover letter. Men are significantly more likely than equally qualified women to apply for a job only when the marginal cost of applying is zero. Introducing either type of application cost, but especially a fee, shrinks the gender application gap. This result comes from gender differences in self-selection behavior: women prefer not to apply when unskilled regardless of costs, whereas unskilled men only drop out of the applicant pool when a tangible cost is introduced. Women appear to face a higher cost than men from applying for a job they might perform poorly at, especially if the job is in a stereotypically "male-typed" domain. Subjective Self-Promotion and Gender Bias in Recruitment Previous work finds that women are more "modest" on average than equally skilled men when subjectively describing their abilities. If recruiters treat self-promotion by men and women as equally informative, they may become inefficiently biased towards male applicants. I randomly vary whether recruiters in a hiring experiment select from applicants who submitted only a resume, or submitted a resume and a cover letter (a type of subjective self-promotion). A cover letter requirement significantly reduces women's share of hires, even as it increases women's share of total applications. This hiring penalty against women cannot be explained by differences in qualifications or skills between men and women who choose to write cover letters. In fact, while employers see productivity gains from requiring a cover letter, such gains would be larger if cover letters did not bias recruiters towards male applicants. Textual analysis reveals that women’s cover letters contain half as much “boasting” language as men’s letters, which could help explain why cover letters impose a penalty on women's chances of getting hired. Anticipated Returns to "Clearing the Bar'': Gender Differences in Job Search Beliefs Conventional wisdom states that women are less willing than men to apply for a job for which they feel only partly qualified. Is this due to gender differences in anticipated returns to meeting or exceeding the desired level of qualification for a job? In a series of studies, I investigate whether men and women rate more and less qualified candidates’ chances of being hired differently. In the lab, I elicit beliefs about callback and offer likelihood by having subjects "bet" on the outcomes of other applicants' job searches. In a stylized online labor market experiment, I observe subjects' job application decisions and elicit beliefs regarding how qualified they will appear to a recruiter. Across studies, I find that women anticipate the same or greater returns than men to moving from "not at all" to "somewhat" qualified for a position, but the same or lower returns to moving from "somewhat" to fully or "highly" qualified. Controlling for gender differences in willingness to rate one's own or others' resumes as qualified does not change the pattern of results. Consistent with these findings, women in my experiment do not differ from men in how likely they are to apply if they fulfill some, but not all, of the listed qualifications in a job posting.Thesis (PhD) — Boston College, 2024.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Economics
Essays in Industrial Organization and Applied Econometrics:
No full textThesis advisor: Arthur LewbelThis dissertation comprises three essays on empirical industrial organization (IO) and applied econometrics. The first and third chapters focus on identification approaches in structural models, with the first chapter dedicated to addressing limitations in demand modeling, while the third chapter studies identification in a triangular two-equation system. The second chapter applies modern econometric tools to understand policy-related topics in IO. The first chapter deals with identification in structural demand modeling, and generalizes the current framework in the literature to achieve a more accurate estimation of differentiated products demand. Within the framework of Berry (1994) and Berry, Levinsohn, and Pakes (1995), the existing empirical industrial organization literature often assumes that market size is observed. However, the presence of an unobservable outside option is a common source of mismeasurement. Measurement errors in market size lead to inconsistent estimates of elasticities, diversion ratios, and counterfactual simulations. I explicitly model the market size, and prove point identification of the market size model along with all demand parameters in a random coefficients logit (BLP) model. No additional data beyond what is needed to estimate standard BLP models is required. Identification comes from the exogenous variation in product characteristics across markets and the nonlinearity of the demand system. I apply the method to a merger simulation in the carbonated soft drinks (CSD) market in the US, and find that assuming a market size larger than the true estimated size would underestimate merger price increases. Understanding consumer demand is not only central to studying market structure and competition but also relevant to the study of public policy such as taxation. In the second chapter, we examine household demand for sugar-sweetened beverages (SSB) in the U.S. Our goal is to understand the distributional effect of soda taxes across demographic groups and market segments (at-home versus away-from-home). Using a novel dataset that includes at-home and away-from-home food purchases, we study who is affected by soda taxes. We nonparametrically estimate a random coefficient nested logit model to exploit the rich heterogeneity in preferences and price elasticities across households, including SNAP participants and non-SNAP-participant poor. By simulating its impacts, we find that soda taxes are less effective away-from-home while more effective at-home, especially by targeting the total sugar intake of the poor, those with high total dietary sugar, and households without children. Our results suggest that ignoring either segment can lead to biased policy implications. In the final chapter, we show that a standard linear triangular two equation system can be point identified, without the use of instruments or any other side information. We find that the only case where the model is not point identified is when a latent variable that causes endogeneity is normally distributed. In this non-identified case, we derive the sharp identified set. We apply our results to Acemoglu and Johnson's (2007) model of life expectancy and GDP, obtaining point identification and comparable estimates to theirs, without using their (or any other) instrument.Thesis (PhD) — Boston College, 2024.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Economics
Three Essays in Investments:
Get PDFThesis advisor: David H. SolomonMy dissertation comprises three essays delving into questions that contemporary investors encounter in the ever-evolving landscape of investments. The first essay examines how the presence of public pension funds as limited partners influences venture capitalists' (VCs) risk-taking behaviors. It notes that investments by public pension funds in the venture capital market have increased over the past two decades, and these funds possess unique objective functions compared to other venture capital investors. Findings suggest that VCs backed by public pensions tend to invest in startups with lower-risk profiles, such as those with technologies related to public companies, numerous patents, and later funding rounds, leading to more frequent and quicker exits but lower returns. To establish causality, I employ an instrumental variable evaluating the likelihood of public pension funding based on the location of funds initiated during a typical fundraising cycle in a venture capital firm. Furthermore, I find that public pensions prefer venture capital firms with a track record of conservatively managing funds, particularly those pensions that have previously engaged with such firms. The second essay shifts focus to the stock market, documenting higher returns from companies developing new technologies. The advancement of new technologies is pivotal to an economy’s potential, yet it carries inherent risks. As per investment theories, investors demand premiums for holding stocks associated with high uncertainty, prompting questions about whether they are adequately compensated for investing in companies undertaking highly uncertain projects. A novel application of a graph-neural network model identifies new technology patent publications annually, enabling the calculation of firms' exposure to new technologies. With the measure, I find that portfolios with high new-tech exposure outperform those with low exposure, driven by significant risk premiums. This sheds light on the positive correlation between idiosyncratic risk and stock returns, contributing to our understanding of the market's valuation of technological innovation. The third essay presents a systematic analysis of stock market valuations of Corporate Social Responsibility (CSR) initiatives. The study identifies public demand for CSR as a pivotal factor in enhancing the value of CSR activities. Analyzing market reactions to CSR activities via cumulative abnormal returns, the research finds overall neutral market responses. Nonetheless, it finds that heightened public concern for specific issues can sway market reactions positively. Also, when CSR initiatives employ strategies that extend beyond the capabilities of individuals, the market responses tend to be favorable. The paper further shows that firms strategically increase their CSR activities and choose implementation modes, aiming to enhance their value. To explain why market reactions are, on average, neutral, I further provide evidence suggesting reasons such as virtue signaling, a lack of understanding of the importance of profitability, and other executive motives. Together, these essays deepen our understanding of investments by exploring how financial market participants, corporate endeavors in technological advancements, and societal expectations for corporate social responsibility influence investor behavior and asset prices.Thesis (PhD) — Boston College, 2024.Submitted to: Boston College. Carroll School of Management.Discipline: Finance
Cultivating Social Justice Pedagogical Knowledge and Skill: A Superintendent's Development of Social Justice Pedagogical Knowledge and Skill
No full textThesis advisor: Martin ScanlanMany district and school leaders have leveraged instructional leadership or social justice leadership to advance student achievement for minoritized students. While research has examined these approaches separately, we identify a potential gap at the nexus between instructional and social justice leadership. In particular, we find a need for further research that examines how leaders bridge instructional and social justice leadership practices, to disrupt educational inequities. Our study examines how educational leaders weave instructional and social justice leadership skills to cultivate others' social justice pedagogical knowledge and skill. Employing a collective case study framework, this study explores how a mid-sized urban district’s superintendent and school leaders cultivated and promoted the social justice pedagogical knowledge and skill of others. Data was collected through interviews, surveys, and document reviews. The primary research participants included one superintendent, two assistant superintendents, three central office leaders, five school leaders, and six teachers. Our findings highlight four themes: the importance of leaders’ critical self-reflection perceptions of district-level infrastructure and strategic planning, school-level instructional infrastructure and capacity building, and gaps in social justice pedagogical skill. This research has implications for practice, policy, and existing literature related to the cultivation and enactment of social justice pedagogical knowledge and skill across diverse contexts.Thesis (EdD) — Boston College, 2024.Submitted to: Boston College. Lynch School of Education.Discipline: Educational Leadership and Higher Education
Diego y yo: Frida Kahlo's Final Self-Portrait Bust
No full textThesis advisor: Kevin LoteryFrida Kahlo’s 1949 painting Diego y yo is the Mexican artist’s final self-portrait bust. This thesis argues for the recognition of the self-portrait as definitive to, what I call, Kahlo’s “early-late style” and as one reason for her shift to still-lifes. The context of the painting revolves around Kahlo’s relationship with her husband Diego Rivera. Their mentor-student relationship is an important facet to understanding motifs in the self-portrait and across Kahlo’s oeuvre as a whole. The artist’s self-portrait includes a superimposed, miniature portrait of Rivera with a third eye in Kahlo’s third eye position. The self-portrait is a culmination of iconography that was only seen in separate contexts previously. My thesis applies a psychoanalytic approach to understand Kahlo’s interactions with herself and the “self” of the portrait. As part of Kahlo’s early-late style, Diego y yo represents a change in her artistic style that is of a new energy of technicality and self-analysis.Thesis (BA) — Boston College, 2024.Submitted to: Boston College. Morrissey School of Arts and Sciences.Discipline: Art, Art History, and Film.Discipline: Departmental Honors
ATheological Ethical Framework for Dalit Lifeworld: ‘Hope in Justice’ as Liberative Praxis in India
No full textThesis advisor: James F. KeenanThis dissertation focuses on the theological ethical framework of ‘hope in justice’ for addressing the caste discrimination, particularly within the context of the Dalit lifeworld in India. It draws parallels between the caste system in India, racial discrimination in the United States, and apartheid in South Africa. More importantly, it examines the leadership and resistance models of Dr. B.R. Ambedkar and Martin Luther King Jr. The dissertation suggests that when the theological ethical enquiry is grounded in the principles of human dignity, justice, and equality, the exercise proclaims hope of liberation for the marginalized in the respective contexts. Further, it employs an ‘ethic of recognition’ as a foundational agenda, uniting various pedadisgogies and praxes against discrimination. This ethic is explored through the philosophical and theological implications of the works of scholars like Judith Butler, James Keenan, Joseph Flipper, Vincent Lloyd, Nelson Mandela, Desmond Tutu, Albert Nolan, Emmanuel Katongole, Jurgen Moltmann, and John Sunder Boopalan. It argues for a comprehensive theological ethical discourse on caste, emphasizing the need for a moral critique and corrective vision based on virtue ethics and the principles of Catholic Social Teaching. To sum up, the dissertation presents a detailed examination of caste discrimination through a theological ethical lens, advocating for a comparative study with racial discrimination to enhance the understanding and develop effective strategies for social change. It underscores the importance of leadership, resistance, and an ethic of recognition in the fight against systemic oppression and inequality.Thesis (PhD) — Boston College, 2024.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Theology
Feeling the Weight of the World: Managing Tensions in the Grand Challenge of Emerging Technology Development
No full textThesis advisor: Elizabeth RouseSociety faces a variety of grand challenges: global problems that must be addressed through coordinated and collaborative effort such as reducing global poverty, effective management of natural resources, and balancing innovation and security in the development of emerging technologies. Management researchers have made great strides in conceptualizing what makes these challenges unique, why they are especially difficult to solve, and how organizations can help solve them. Despite this progress, we lack an understanding of the experience of the “grand challenge workers” who seek to address these problems, including the unique difficulties they face in their work and how they overcome them. Through a qualitative, inductive study of workers seeking to ensure the safe development of artificial intelligence and biotechnology, I explored the pressures and worrying thoughts that lead these workers to experience work performance anxiety. I show how, in response to this anxiety, workers engage in various bounding and reframing practices to limit the demands their work places on them and expand their sense of the resources available to them. I also illustrate how these workers relate to grand challenge communities: groups focused on coordinating efforts to address the grand challenge. I build theory around the contextual factors that lead workers to rely heavily on these communities and subsequently adopt an exclusive solidarity approach to addressing the grand challenge. I show how these workers recognize the threats this approach poses to their judgment, well-being, and effectiveness, and how they shift toward an expansive solidarity approach. Practically, this research provides insights into how these workers respond to the challenges they face in ways that enable them to address the grand challenge while also preserving their well-being.Thesis (PhD) — Boston College, 2024.Submitted to: Boston College. Carroll School of Management.Discipline: Management and Organization
Charging Forward: The Impact of State Incentives on Electric Vehicle Adoption and Emission Reduction Targets
No full textThesis advisor: John J. PideritThis paper examines state and county-exclusive incentives on battery electric vehicle (BEV) registration in the United States. Using two main methods, a differences-in-differences method and a sigmoidal growth rate equation, I examine the impact of non-federal incentives on the total amount of electric vehicles between 2017 and 2022, as well as estimate the years that each state will reach its net-zero goals for carbon emissions in the transportation sector. I hope to provide a deeper understanding of the effectiveness of incentive policy, based on differing levels of incentive policy between regions, in order to best increase electric vehicle adoption in a cost-effective method. In addition, I hope that my estimates of net-zero projections will serve as a beneficial comparison to track states’ respective progress towards sustainable energy in vehicles. These findings can be used to assist policymakers in determining appropriate BEV adoption policies based on regional consumer demographics and needs, as well as visualize a timeline for the next century of rapid electric vehicle growth.Thesis (BA) — Boston College, 2024.Submitted to: Boston College. Morrissey School of Arts and Sciences.Discipline: Economics.Discipline: Departmental Honors
From Classroom to Paycheck: The Impact of CTE Vocational Programs on Wages in Massachusetts
No full textThesis advisor: Joanna VenatorThis paper explores the impact of Career and Technical Education (CTE) programs on wage outcomes in the U.S. labor market, particularly against a backdrop of shifting economic conditions and workforce needs. The study delves into how various CTE programs, specifically state-approved programs with stringent standards and federally- approved programs with more flexible requirements, shape the wage trajectories of high school students. The analysis is structured in two main phases: the first phase involves a detailed mapping of CTE courses to real-world occupations as categorized by the North American Industry Classification System (NAICS), highlighting the alignment -- or lack thereof -- between educational offerings and labor market demands. The second phase employs an Ordinary Least Squares (OLS) regression with fixed effects to analyze the influence of CTE program participation on wage outcomes across different industry sectors and counties. This approach allows for a nuanced examination of how local industry definitions affect the perceived effectiveness of CTE programs and underscores the complex trade-offs involved in prioritizing vocational training for immediate employment versus broader educational and career advancement opportunities. The findings reveal significant variability in the impact of CTE programs on wages, influenced by the specificity of job sectors and the breadth of skills taught, with implications for policy decisions aimed at enhancing the role of vocational education in fostering economic mobility.Thesis (BA) — Boston College, 2024.Submitted to: Boston College. Morrissey School of Arts and Sciences.Discipline: Economics.Discipline: Departmental Honors