In chapter 1, I ask whether an exchange rate depreciation depresses trading partners' output. I address this question through the lens of a classic episode: the currency devaluations of the 1930s. From 1931 to 1936, many of the biggest economies in the world successively left the gold standard or devalued, leading to a depreciation of their currency by more than 30% against gold. In theory, the effect is ambiguous for countries that did not devalue: expenditure switching can lower their output, but the monetary stimulus to demand might raise it. I use cross-sectional evidence to discipline the strength of these two mechanisms in a multi-country model. This evidence comes in two forms: (i) causal inference of the effect of devaluation on country-level variables, (ii) new product-level data to estimate parameters that are essential to discipline the response of trade --- the international elasticity of substitution among foreign varieties, and the pass-through of the exchange rate to international prices. Contrary to the popular narrative in modern policy debates, devaluation did not dramatically lower the output of trading partners in this context. The expenditure switching effect was mostly offset by the monetary stimulus to foreign demand. In chapter 2, Emi Nakamura, Jon Steinsson, and I provide new estimates of the evolution of productivity in England from 1250 to 1870. Real wages over this period were heavily influenced by plague-induced swings in the population. We develop and implement a new methodology for estimating productivity that accounts for these Malthusian dynamics. In the early part of our sample, we find that productivity growth was zero. Productivity growth began in 1600---almost a century before the Glorious Revolution. Post-1600 productivity growth had two phases: an initial phase of modest growth of 4% per decade between 1600 and 1810, followed by a rapid acceleration at the time of the Industrial Revolution to 18\% per decade. Our evidence helps distinguish between theories of why growth began. In particular, our findings support the idea that broad-based economic change preceded the bourgeois institutional reforms of 17th century England and may have contributed to causing them. We also estimate the strength of Malthusian population forces on real wages. We find that these forces were sufficiently weak to be easily overwhelmed by post-1800 productivity growth. In chapter 3, Carlo Altavilla, Miguel Boucinha, and I propose a new methodology to identify aggregate demand and supply shocks in the bank loan market. We present a model of sticky bank-firm relationships, estimate its structural parameters in euro area credit register data, and infer aggregate shocks based on those estimates. To achieve credible identification, we leverage banks' exposure to various sectors' heterogeneous liquidity needs during the COVID-19 Pandemic. We find that developments in lending volumes following the pandemic were largely explained by demand shocks. Fluctuations in lending rates were instead mostly determined by bank-driven supply shocks and borrower risk. A by-product of our analysis is a structural interpretation of two-way fixed effects regressions in loan-level data: according to our framework, firm- and bank-time fixed effects only separate demand from supply under certain parametric assumptions. In the data, the conditions are satisfied for supply but not for demand: bank-time fixed effects identify true supply shocks up to a time constant, while firm-time fixed effects are contaminated by supply forces. Our methodology overcomes this limitation: we identify supply and demand shocks at the aggregate and individual levels. In chapter 4, I study how the fiscal side of the US government reacts to monetary policy. I estimate the response of several fiscal variables to monetary shocks. Following an interest rate hike, tax receipts fall, outlays excluding interest payments are constant, and interest payments and debt increase. The fall in output that follows a monetary tightening --- not legislated changes in marginal tax rates --- drives the response of receipts. The fiscal authority therefore responds passively to monetary shocks, keeping expenditures constant and letting debt adjust to satisfy its budget constraint. In heterogeneous agent models, this scenario dampens output's response to monetary policy.

My philosophically informed empirical project seeks to shed light on the importance of a teacher’s caring work in schools and the difficulties encountered in performing this work so as to elicit more collective action towards supporting teachers in their role as care workers. Teaching is one profession where doing good work has been made tremendously difficult by the ongoing COVID-19 pandemic. Nonetheless, long before the pandemic, the working conditions for public school teachers have been far from supportive of the good work that they strive to do. Focusing on U.S. public school teachers and their engagement in complete care for students, my project addresses two central questions: How does completing care in students look like in teaching? and Why should the public support its teachers? “Complete care,” a concept from care ethics that I examine and articulate in my project, seeks to guide care-giver(s) in caring relationships towards successfully meeting the needs of the care recipient, thereby promoting their well-being or flourishing. To show that teachers encounter several constraints in completing care in students, my study draws on a variety of empirical and philosophical sources, including the testimonies of eight public school teachers whom I interviewed in Spring 2021 on their endeavors of meeting the needs of students before and during the pandemic. The experiences of teachers working in a “corporatized” public school environment point to the moral challenges that a teacher could face in fulfilling their caregiving responsibilities to students. In light of the moral precarity that teachers can be exposed to from working in times of difficulty, I argue that the larger social order, where possible, should provide the conditions necessary for teachers to competently complete care for students in schools.

The accumulation of misfolded proteins within intracellular aggregates is a distinctive feature observed within multiple neurodegenerative diseases (NDDs). However, the genes and pathways that regulate protein misfolding, aggregation, and subsequent cellular toxicity remain poorly understood. Here I describe a high-throughput discovery platform that enables the simultaneous screening of dozens of neurodegenerative disease models to rapidly uncover genetic modifiers that alter the solubility and toxicity of a wide variety of aggregation-prone proteins. From these studies, I identify the human HSP40 chaperone, DNAJB6 as a potent rescuer of the misfolding and proteotoxicity of multiple RNA-binding proteins implicated in Frontotemporal dementia (FTD) and Amyotrophic Lateral Sclerosis (ALS) including FUS, TDP-43, and hnRNPA1. I, with collaborator help, further demonstrate that DNAJB6 has an intrinsic ability to phase separate under physiologic conditions and can alter the properties of FUS containing condensates by maintaining them in a gel-like state over long periods, preventing FUS aggregation. By conducting domain mapping studies and a deep mutational scan on DNAJB6, I am able to gain detailed insight into its mechanism of action while also uncovering a series of novel variants with enhanced activity. During the development of this multiplexed screening approach for neurodegenerative disease models, research was interrupted by a global pandemic caused by SARS-CoV-2. I realized that the themes of studying proteotoxicity of multiple related, yet distinct models could be applied towards drug development to identify inhibitors of the essential 3CL proteases encoded by multiple coronaviruses, which cause proteotoxicity when expressed in cells. As such, I develop and describe a mammalian cell-based assay to identify coronavirus 3CL protease (3CLpro) inhibitors. This essay is based on rescuing protease-mediated cytotoxicity and does not require live virus. By enabling the facile testing of compounds across a range of 15 distantly related coronavirus 3CLpro enzymes, I identify compounds with broad 3CLpro inhibitory activity. I also adapt the assay for use in compound screening and in doing so uncover additional SARS-CoV-2 3CLpro inhibitors. I observe strong concordance between data emerging from this assay and those obtained from live virus testing. The reported approach democratizes the testing of 3CLpro inhibitors by developing a simplified method for identifying coronavirus 3CLpro inhibitors that can be used by the majority of laboratories, rather than the few with extensive biosafety infrastructure. I identify two lead compounds, GC376 and compound 4, with broad activity against all 3CL proteases tested including 3CLpro enzymes from understudied zoonotic coronaviruses.

This dissertation contains three essays in financial economics. The focus of the dissertation is to study how retail investors and the financial market react to the arrival or the possibility of disastrous events. In the first chapter, I explore the portfolio reaction to evidence of climate change by looking at how retail investors trade when they locally experience abnormal temperature. I test the hypothesis that retail investors will trade out of high emission stocks and trade into low emission stocks when experiencing abnormally high temperature through a channel of climate belief updating. Using detailed administrative records of retail investors’ positions and trading activities from a large financial institution, I construct measures of trading imbalances at the zip code level for various types of stocks and study the impact from abnormal temperature. I do not find evidence that investors trade out of high emission stocks or trade into low emission stocks when experiencing abnormally high temperature. The estimated effects are neither economically nor statistically significant. Moreover, investors are not dynamically adjusting their portfolios in response to abnormal temperature. The nonresults are robust if I implement the estimations in quarterly or annual frequency. Focusing on only trading activities in the energy sector does not change the results. Analyzing subsamples of investors with different levels of beliefs in climate change also produces nonresults. Although past literature has shown that local extreme temperature can induce changes in beliefs about climate change and related behavior, this paper shows that such belief updating does not translate into response in portfolio choice.In the second chapter, we model the contribution of a vaccine to the rebound in corporate earnings the year following the onset of COVID-19 while accounting for the role of fiscal and monetary measures. A vaccine that reopens the economy leads to a jump in earnings, while temporary fis- cal and monetary support for households and businesses leads to higher short-run earnings growth before a vaccine arrives. We show that our model can be consistently estimated using revisions of value-weighted industry-level consensus earnings forecasts. We first present reduced-form evidence that security analysts account for both effects. Our model estimates then suggest that the reopening effect is as important as the short-run growth effect in explaining the rebound in corpo- rate earnings. The third chapter studies the partisan difference in trading behavior at the onset of the COVID-19 pandemic. Partisanship drives disagreement on the severity and persistence of the COVID-19 shock when it hit the US. Republicans were more optimistic than the Democrats when evaluat- ing the potential damage of COVID-19 to the economy. Using detailed administrative records of retail investors’ positions and trading activities from a large financial institution, I find that the partisan disagreement on COVID-19 is reflected in stock trading behavior: Republicans had more net flow into equity than the Democrats from March to May of 2020. Moreover, the difference is concentrated on industries with high face-to-face interactions and highly levered firms, which are expected to be more severely damaged by COVID-19. The results suggest that disagreement rooted in partisanship can have a real impact on household financial decisions and potentially on the overall financial market.

The lungs are the primary organ of the respiratory system. Their main function is to provide freshly breathed oxygen (O²) to the blood capillaries, while taking carbon dioxide (CO²) from them and expelling it to the atmosphere. Lung conditions such as Acute Respiratory Distress Syndrome (ARDS), Idiopathic Pulmonary Fibrosis (IPF), Coronavirus Disease (COVID-19), etc., cause impaired gas exchange that is life-threatening. In this dissertation, I developed 1) a physiology-based dynamic pulmonary system to study the lung normo- and patho-physiology, and 2) a model-based constrained optimization algorithm to do parameter estimation in order to non-invasively assess lung health. The goals of this work are 1) to accomplish a respiratory personalized medicine example for clinical decision support, and 2) to further the understanding of respiratory physiology, via a mechanistic physiology-based model and system identification techniques. The mechanistic model presented in this thesis comprises six subsystems: 1) a lung mechanics module that computes airflow transport from the mouth and nose to the alveoli (gas exchange units), 2) a respiratory muscles and rib cage mechanics module that simulates the effect of the respiratory muscle contraction on the lungs and the rib cage, 3) a microvascular exchange system that describes fluid (water) and mass (albumin and globulin) transport between the pulmonary capillaries and the alveolar space, 4) an alveolar elasticity module that computes alveolar compliance as a function of the pulmonary surfactant concentration and the elastic properties of the lung tissue fiber, 5) a pulmonary blood circulation that describes blood transport from the heart to the pulmonary system, and 6) a gas exchange system that describes O² and CO² transport between blood in the pulmonary capillaries and gas in the alveoli. Each subsystem was developed based on the latest knowledge of lung physiology and was validated using patient data when available or published and validated physiology-based models. To our knowledge, the combined six-module model would be the most rigorous and expansive lung dynamic model in the literature. This dynamic respiratory system can be used to describe human breathing under healthy and diseased conditions. The model can readily be used to test different what-if scenarios to find the optimal therapy for the patients. Further, I tailor the proposed lung model and adopt system identification techniques for noninvasive assessment of the lung mechanical properties (resistance and compliance) and the patient breathing effort. Pulmonary syndromes or diseases, such as ARDS and COPD (Chronic Obstructive Pulmonary Disease) evoke alterations in lung resistance and compliance. These two parameters reflect, by and large, the state of health and functionality of the respiratory system. Hence tracking these two parameters can lead to better disease diagnosis and easier monitoring of the respiratory disease progression. For spontaneously breathing patients on ventilatory support, the estimation of the lung parameters is challenging due to the added patient’s breathing effort. This dissertation presents a model-based nonlinear constrained optimization algorithm to estimate, breath-by-breath, the lung resistance, the lung compliance, as well as the patient breathing effort due to the respiratory muscle activity, using readily available non-invasive measurements (airway opening pressure and airflow).

As the COVID-19 pandemic continues to reshape how organizations operate, working from home has become more prevalent. While working from home is not new, organizations face unique challenges in fostering an inclusive virtual work environment. This modified qualitative case study was designed to explore with a group of 20 organizational leaders their perceptions of what is needed to create a more inclusive virtual work environment and how they learned to foster such an environment. The researcher based his study on five assumptions: (1) inclusivity for virtual employees and teams is possible; (2) the virtual team leaders are capable of learning how to be inclusive leaders; (3) there is a correlation between innovation and diversity, thus, inclusion matters more than ever, and all team leaders are focusing on becoming more inclusive; (4) the use of different technologies for communication is essential in creating an inclusive environment; and (5) a more inclusive work environment involves managing and changing power dynamics. The study population includes virtual team leaders who managed teams during and before the global pandemic. Participants’ teams were either 100% virtual and/or hybrid. The primary sources of data were in-depth semi-structured interviews of 20 team leaders, a virtual focus group of four team leaders, and critical incident reports. Key findings of the study revealed: (1) All participants indicated that managers’ support was critical in a virtual work environment, while an overwhelming majority of participants described that establishing human connection among the population is vital in a virtual work environment; (2) An overwhelming majority of participants described that creating a psychological safety net and promoting diversity, equity, and inclusion are two essential elements in a virtual work environment; (3) An overwhelming majority of participants indicated that building cohesion among working models was a key challenge in creating and supporting an inclusive virtual work environment; and (4) A strong majority of participants described they learned to create an inclusive virtual work environment primarily through informal ways like critical reflection. Numerous recommendations were provided for current and aspiring organizational leaders, including team leaders, people managers, and multiple stakeholders—such as senior executives and HR professionals. These recommendations include suggestions for implementing practices that increase connection among team members, establish clear policies and guidelines for virtual collaboration, provide guidance for how to build a culture of psychological safety, how to use technology to facilitate more open communication and transparency, and suggestions for how to create an inclusive hiring process.

This study explores the experiences of science and mathematics teachers during the Triple Pandemic: a pandemic of COVID-19, poverty, and racism. The intersection of COVID-19, poverty, and racism created a novel educational context for teachers to navigate. Using an intersectional qualitative case study approach, this study highlights the stories of three middle school science and mathematics teachers as they strove to meet the needs of their students during a time of crisis brought forth by COVID-19 and as pre-existing systemic inequities surfaced during the period of remote learning. Using data collected from an initial and final questionnaire (Likert scale and open-ended), semi-structured interviews, audio journal entries, and a focus group this study sought to capture the teachers’ experiences, their emotions, adjustments to teaching practice, and challenges encountered. Guided by a conceptual framework integrating Sensemaking Theory, Critical Consciousness, Positional Identity, and Science Identity as a Lived Experience, this study further examined the ways teaching remotely developed, shifted, and affirmed their science and mathematics identities and the impact of sensemaking of their experiences had on their educational priorities. The findings highlight the participants' emotionally charged and challenging experiences as they made sense of their roles as science and mathematics teachers and gained an increasing awareness of systemic inequities. The three participants developed a critical consciousness through their confrontation of inequities, increased racial identity, and development of their critical agency. Additionally, the participants’ sensemaking of the educational context produced by the Triple Pandemic resulted in the development of new educational priorities reflecting social justice engagement on micro and meso levels and in identity tensions as science and mathematics teachers.

There is a high prevalence of mental health challenges among immigrant-origin youth (IOY) as a consequence of unique stressors and risk factors, disparities in access to mental health services, and distress associated with the COVID-19 pandemic. Educators and school staff are in need of effective, accessible, and culturally relevant mental health literacy (MHL) training to accurately recognize and appropriately respond to these mental health concerns. The main goal of this pilot study was to examine initial evidence on the effectiveness, utility, acceptability, and cultural fit of the virtual format of the Youth Mental Health First Aid (YMHFA) training program among educators who work with IOY. A mixed-methods approach was employed through quantitative online surveys at pre-training, post-training, and three-month follow-up as well as qualitative virtual focus groups querying educator and school staff’s perspectives. Descriptive and inferential analyses were used to quantitatively analyze survey data. Thematic analysis was used to analyze qualitative data. Findings obtained from a total of 36 educators and school staff working predominantly IOY revealed significant improvements in participants’ mental health knowledge, confidence to help, and attitudes towards mental illness that were sustained at three-month follow-up, with some variability based on race, prior mental health training experience, and professional role. The content and format of the virtual YMHFA was also found to be highly rated in its utility and acceptability. Themes related to utility included (a) crisis response skills and knowledge and (b) flexible scope of use of the training. Themes related to acceptability included the (a) presentation of information, (b) accessibility and convenience, (c) interactive nature of the training, (d) timing and scheduling, and (e) limited content. Themes highlighting the strengths and weaknesses associated with the cultural relevance of the training included (a) inclusivity and specificity and (b) cultural sensitivity and awareness. Themes related to recommendations to improve the cultural relevance of the training included (a) additional knowledge and resources, (b) improving representation in scenarios and videos, and (c) tailoring content to a target audience. Based on these initial findings, several implications for implementation of YMHFA training in schools, improving the cultural relevance of YMHFA for IOY, and future directions in research are discussed.

As reflected in the surge of anti-Asian discrimination following the outbreak of COVID-19, Asian Americans continue to face subtle and overt forms of racism despite the misguided popular image as the “model minority.” Prior research has found that perceived discrimination experiences are associated with adverse mental health outcomes for Asian Americans. The current study extends the literature by exploring pathways that link perceptions of discrimination and psychological distress and protective factors that disrupt this link. The study tested a moderated mediation model that included internalized racism as a mediator and critical action and ethnic identity as moderators, utilizing the bootstrap-based PROCESS analysis (Hayes, 2013). Participants were 424 Asian American adults ranging in age from 18 to 73 that completed an online survey. Results indicated that internalized racism mediated the relation between perceptions of discrimination and psychological distress. Critical action, but not ethnic identity, significantly moderated the mediated effect of racial discrimination on psychological distress through internalized racism. Specifically, among Asian Americans that reported high levels of critical action, internalized racism did not the mediate the relation between perceived racial discrimination and psychological distress. Findings are discussed in terms of their implication for clinical practice, educational and community programming, and advocacy efforts for Asian Americans.

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has proved to be the greatest global crisis of the 21st century and has led to a devastating state of human health and societal infrastructure. Such calamity was met with immense determination from the scientific community to uncover the immunological and virological basis of its accompanying disease and resulted in remarkable feats of public health response and therapeutic design. As SARS-CoV-2 continues to evolve and elicits a heterogenous disease presentation across different demographics, we aimed to define the circulating and tissue-localized immune memory generated following SARS-CoV-2 infection, as well as determine the immunological properties governing severe disease. Using human tissues from seropositive organ donors, we showed that SARS-CoV-2-specific immune memory was present in circulation, lymphoid, and mucosal sites up to 6 months post infection. B and T cell populations mounted against SARS-CoV-2 showed significant correlations between circulating and tissue-resident memory lymphocytes, suggesting local and systemic tissue coordination of cellular and humoral immunity against SARS-CoV-2, set for optimal protection against future infectious challenges. Next, we presented a comprehensive, longitudinal study of the peripheral blood immune system following pediatric SARS-CoV-2 infection and provided new insight on the immunological underpinnings of multisystem inflammatory syndrome in children (MIS-C). Acute MIS-C and pediatric COVID-19 differ in their effector module elicitation, activating opposing type 1 and type 2 immune responses respectively. We reveal that MIS-C presents with a unique peripheral T cell signature marked by activation, exhaustion, and tissue-residency at the proteomic and transcriptional level, along with a major Vβ-biased clonal expansion. Despite the considerable immune dysregulation during acute disease, children recovered from MIS-C maintain stable humoral immunity up to 18 months post hospitalization at comparable levels to seropositive groups, and generate robust, functional T cell memory in greater magnitude than seropositive children. Together, we report a near-complete restoration in global T cell phenotype and function in children following MIS-C, as well as the robust production of competent SARS-CoV-2 specific memory. Finally, following our queries into SARS-CoV-2-specific antiviral immunity, we sought to delineate the dynamics of human follicular immune responses and its role in generating and maintaining humoral immunity across a lifespan. Using healthy pediatric and adult donor tissues to examine blood, lymphoid, and mucosal tissues, our results reveal that TFH cells predominate the CD4+ T-cell memory pool in lymphoid sites in early life and decline in frequency with age. Further, pediatric and adult TFH cells differ in their functional capacities, with pediatric TFH cells expressing higher levels of markers associated with signal regulation and germinal center function, while adult TFH cells demonstrate a TH17-like identity. Further, early life TFH cells in lymphoid exhibit marked TCR repertoire overlap. Together, these results indicate a differential propensity for follicular responses in early life and adulthood, with important implications in considering immunomodulatory strategies in different life stages.