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UC Santa Cruz Electronic Theses and Dissertations

Cover page of From Calcutta to the Bengal Tiger: Indian Musicians, American Orientalism, and Cosmopolitan Modernism Pre-1947

From Calcutta to the Bengal Tiger: Indian Musicians, American Orientalism, and Cosmopolitan Modernism Pre-1947

(2023)

This dissertation excavates a forgotten history of Hindustani (North Indian) art music in the United States beginning with Bengali musician and restaurateur Sarat Lahiri (c. 1897-1941), whose name surfaces peripherally in the academic literature on American composer Henry Cowell (1897-1965), the New School for Social Research, and the 1930s Manhattan restaurant trade. By tracing scattered archival references to Lahiri and reconstructing a network of his collaborators, my research centers the migrations and activities of musicians from colonial India in the decades preceding Indian independence in 1947. These early-twentieth-century migrants navigated a world shaped by European colonialism, global anticolonial movements, nativist racism and legal exclusion in the United States, and the exoticist fantasies and commercial pressures of American Orientalism. They traversed social and economic landscapes characterized by sweeping change, unexpected encounters, and unforeseen hardships. Lahiri’s career in New York between 1923 and 1941 provides a means of engaging the Orientalism of the era, including its expressions in modernist movements in music and dance, and considering how this dynamic milieu shaped the everyday lives of working immigrant musicians. As I situate Lahiri and his contemporaries in contexts ranging from the local to the global, I discuss the involvement of artists, activists, and intellectuals from the Indian subcontinent across multiple domains of American cultural production in the early twentieth century.

Cover page of The Vital Balance Between Pre-mRNA Load and Splicing Capacity

The Vital Balance Between Pre-mRNA Load and Splicing Capacity

(2023)

The spliceosome, a large macromolecular machine that removes introns from pre-mRNA to form mature mRNA, contains five small RNAs that play key roles. To learn more about the role played by one of these, U2, we started with a temperature-sensitive mutant of U2, U33Δ. Using U33Δ, we analyzed secondary mutations that restored growth at a non-permissive temperature in Saccharomyces cerevisiae. We found that this suppressor mutation was in a gene, NOB1, that is unrelated to splicing and instead is a crucial component of ribosomal RNA processing. This mutation, found to be a delta (δ) insert from a Ty transposable element, causes reduced function in Nob1 and an accumulation of unprocessed rRNA. RNA sequencing revealed U33Δ has a splicing defect and change in gene expression, both of which the nob1-Tyδ allele restored. How this rRNA processing defect rescues a spliceosome mutant led us to investigate this phenomenon through the lens of systems biology, and we found that decreasing the load of pre-mRNAs or increasing the capacity of the spliceosome were both able to restore the growth of U33Δ. We found new mechanisms that can change the pre-mRNA pool that rescue mutations in the spliceosome, adding evidence to the hypothesis that splicing regulation is directly related to the spliceosome’s capacity and workload.

Design, Modeling, Simulation, and Fabrication of Origami to Improve Rotational Joint's Performance

(2023)

The use of revolute joints in robotics is widespread, but their performance can still be improved. The goal of this research is to enhance robot joints by utilizing origami structures, which offer numerous benefits such as space efficiency, and reduced production time and costs (due to flat-foldability). In this work, we investigated various origami crease patterns, categorizing and analyzing them based on their movements. Inspired by the earwig wing and Miura-ori unit cell pattern, we designed and fabricated Four-vertex and Self-lock origami models, and analyzed their rotational motions, moments, and actuator pressure relations. The origami designs are simulated with different central angle plates, and constructed using cutting and binding and 3D-printing methods. We developed rotational manipulators and modeled transitional and modular manipulators as proof of concept.

The results of the study demonstrate that origami joints with central angles closer to $90^\circ$ degrees show larger rotational motion changes compared to traditional revolute joints (equivalent to a simple fold) with the same actuator. They save actuator pressure and are deployable in different sizes and weights. Moreover, the position of the central angles in the Self-lock origami affects the direction of movements. The manipulators are used with different central angle plates to illustrate the rotational and transitional movements in different directions. The proposed Self-lock origami joints can generate bi-directional movement and increase moment in specific rotational phases. The joint is also modular and can be connected to similar or different joints to produce complex movements for various applications.

Cover page of From Models to Management: Oceanographic Processes Shaping the Spatial Patterns and Progression of Ocean Acidification and Hypoxia in the California Current System

From Models to Management: Oceanographic Processes Shaping the Spatial Patterns and Progression of Ocean Acidification and Hypoxia in the California Current System

(2023)

The California Current System, situated off the US West Coast, experiences natural exposure to acidified and oxygen-poor conditions due to coastal upwelling, which brings low pH, low oxygen water from depth to the nearshore environment. The addition of anthropogenic ocean acidification and hypoxia (OAH) is therefore pushing conditions below biological thresholds, resulting in a variety of harmful effects ranging from behavior impacts to shell dissolution and mortality. It is therefore important to characterize the progression of ocean acidification and hypoxia in the California Current, where exposure to corrosive and hypoxic conditions is spatially variable and episodic in nature, making it a challenge to describe these patterns and their biophysical drivers through observational data alone. Here, a high resolution (~3 km) coupled physical-biogeochemical model is used to characterize the recent and projected spatial and temporal patterns in exposure to reduced pH and oxygen conditions, along with their physical and biogeochemical drivers. Results from Chapter 1 demonstrate that historical (1988-2010) alongshore variability in pH and oxygen is driven by a complex interplay of upwelling and primary production, modulated by the alongshore and cross-shore regional circulation. Results from Chapter 2 establish that historical variability in the interannual severity of exposure to corrosive conditions is driven by combined changes in source water properties and upwelling intensity, respectively associated with decadal basin scale variability and interannual regional scale forcing. Chapters 3 and 4 utilize downscaled regional climate projections to investigate the future (2000-2100) progression of ocean acidification and hypoxia hot spots, the emergence of these features, and their implications for marine resource management. Results from Chapter 3 highlight that where and when hot spots and refugia for pH and oxygen emerge depends on the metrics used to quantify them. If one is managing for OAH and cares about where and when conditions become distinct from their historical range, the projections suggest hot spots will be located in areas of historically weaker upwelling due to their narrow range of variability. In contrast, if one is managing for OAH and cares about where and when conditions will drop below specific biological thresholds, the projections suggest hot spots will be located in areas of historically stronger upwelling due to their lower baseline pH and oxygen conditions. Chapter 4 synthesizes information from the projections and displays it in an online interactive management tool, where users can explore future OAH change based on their species or region of interest. As a whole, these four chapters provide the first comprehensive mechanistic description of the physical and biogeochemical drivers shaping historical and future alongshore and interannual OAH variability in the central California Current region, while disseminating this information to marine resource managers in an accessible format.

Cover page of Understanding How Social Norms and Affordances Explain Self-Presentation on Social Media

Understanding How Social Norms and Affordances Explain Self-Presentation on Social Media

(2023)

My research focuses on understanding how self-presentation acts on media. In 3 previous projects, I have examined how people present themselves by comparing their offline personality with self-presentations on Snapchat, Facebook, Instagram, Texting, and Video calls. I use mixed methods, combining Big-5 personality surveys and interviews to probe self-presentational differences between media. I have found reliable differences between media and offline self-presentations in those studies. In particular, that Neuroticism is always lower on media across multiple studies. Furthermore, some differences aren’t due only to the affordances of the media, but social norms on that media, which I found when looking at different types of Instagram accounts.

I expand on this work through two additional studies using new methods to explore different research questions. The first study examines how users of multiple media make decisions about where to make a post. I used scenarios to understand how users of multiple media decide between the media that they use and propose a mental model of media choice. First, if there is a quick match between an existing social norm on a medium and their intended post, they will post it there. If there isn’t, then the user must consider the affordances and other social norms of the media they use before deciding where to post.

The second study examines how outside observers interpret an Instagram profile. I presented observers with a dynamic webpage, similar to Instagram, to gather behavioral and survey data on how said observers looked at and interpreted these Instagram profiles. Based on the results, observers don’t see an Instagram specific self-presentation but are more accurate to the profile owner’s offline personality. I finish by presenting my doctoral research's technical and theory-based implications.

Advancing Assays, Exploring Environments, and Mapping Pathways: a Journey Through Hematopoietic Dynamics

(2023)

Hematopoiesis is the process through which hematopoietic stem cells (HSCs) produce all mature and immune cells in the blood. This thesis focuses on three aspects of hematopoiesis research: methods for studying hematopoiesis, the effects of environmental exposures of fetal hematopoiesis, and epigenetic changes influencing hematopoiesis during aging.The first part of this thesis delves into the historical and ongoing significance of the spleen colony-forming unit assay, a pioneering in vivo functional assay to elucidate bone marrow cell functions. Then, the focus shifts to overcoming the limitations of traditional host conditioning methods, introducing innovative mouse models for selective ablations of all hematopoietic cells or HSCs specifically. These models offer non-irradiation alternative for studying HSC function, engraftment ability, and differentiation pathways. Together, these chapters contribute to advancing our understanding of HSC identity and functions. The second part of this thesis investigates the impact of environmental toxic compounds on hematopoiesis and immune function. We specifically reviewed the effects of nicotine on HSCs and other blood cells. Then, we investigated the effects of in utero nicotine exposure on the establishment of the hematopoietic system and we determined its long-term consequences. These chapters collectively offer insights into the perturbations of normal hematopoiesis by environmental exposures during development. The last part of this thesis focuses on unraveling the dynamics of HSC differentiation and lineage fate decisions, with an emphasis on platelet differentiation. First, we reviewed evidence suggesting the existence of a non-canonical platelet differentiation pathway from HSCs, predominantly primarily observed during inflammation. Then, we investigated how epigenetic lineage priming drives differentiation of HSCs into the five mature lineages by maintaining chromatin accessibility at lineage-specific regulatory regions. Finally, we investigated how epigenetic priming of the Nuclear Protein 1 (Nupr1) gene in aged HSCs drives non-canonical platelet differentiation, offering a comprehensive understanding of the intricate processes governing aging hematopoiesis. Ultimately, the studies presented here promise advance in our comprehension of hematopoiesis and open avenues for innovative approaches in regenerative medicine and therapeutic interventions.

Cover page of Cont-RAS-ting the effects of Ras signaling on cell growth and size control

Cont-RAS-ting the effects of Ras signaling on cell growth and size control

(2023)

Severe defects in cell size are a nearly universal feature of cancer cells. Yet, the mechanisms that drive size defects in cancer cells remain unknown, and it is unclear whether they are a direct consequence of primary oncogenic drivers or a secondary consequence of mutations that accumulate during evolution of cancer cells. Hyperactive mutants of Ras are amongst the most prevalent oncogenic drivers. In budding yeast, previous studies have suggested that hyperactive versions of the Ras homolog (ras2G19V) cause defects in cell size. However, the mechanisms by which ras2G19V drives cell size defects are unknown, and it is unclear whether the size defects are due to accumulation of suppressor mutations. Here, I developed a system for inducible expression of ras2G19V that allows for investigation into the immediate consequences of ras2G19V expression. I found that ras2G19V causes a delay in G1 phase, increased cell size, and aberrant expression of G1 cyclin proteins. Furthermore, ras2G19V appears to inhibit a key step in cell cycle entry, in which an early G1 cyclin induces transcription of late G1 cyclins. The data further suggest that Ras does not influence cell size solely via effects in G1 phase. Finally, we found that expression of oncogenic Ras alone is sufficient to cause cell size defects in NIH 3T3 cells, which suggests that defects in cell size in cancer cells could be a direct consequence of primary oncogenic signals. Together, the data suggest that hyperactive forms of Ras influence cell size in both yeast and mammals. Further analysis will determine whether Ras influences cell size via conserved mechanisms.

Wavefunction Mapping and Magnetic Field Response of Electrostatically Defined Graphene Quantum Dots

(2023)

QDs are mesoscopic objects with 3D quantum confinement, which are often called artificial atoms due to their discrete energy levels. Over the past several decades, a tremendous amount of research has been done on semiconductor QDs, which made them one of the most well-studied QD systems and a testbed for studying rich quantum phenomena that can be hosted in QD systems. But more recently, a new type of QD that is based on atomically thin graphene materials attracted the attention of the condensed matter physics community because of the unique electronic structures hosted by graphene materials. Compared to conventional semiconductor QDs, graphene QDs offer a distinctive platform to study the interplay between quantum confinement, relativistic quantum phenomena, and non-trivial band geometrical properties. Such properties cannot be investigated in conventional semiconductor QDs. During my Ph.D. study, my research focused on investigating the electronic structure and magnetic field response of these relatively new graphene QDs. To experimentally probe graphene QD states, I used an unconventional but very powerful in-situ graphene QD creation and probing technique with STM, which enabled us to gain information of graphene QD states with atomic scale spatial resolution and meV energy resolution. Such capability of our experimental approach enabled us to gain insights on graphene QD states that are out of reach with conventional electron transport measurements. In this dissertation, I will include experimental findings from four graphene QD projects that I participated in during my Ph.D. study. This includes the observation of giant orbital magnetic moments and paramagnetic shift in MLG QDs due to their relativistic nature (chapter 5), the effect of Berry curvature and Fermi surface symmetry on the spatial distribution of BLG QD wavefunctions (chapter 6), giant valley Zeeman splitting in TLG QDs due to the giant topological orbital magnetic moment hosted in this system (chapter 7), and the unambiguous direct visualization of the relativistic quantum scars in stadium shaped MLG QDs (chapter 8). These results demonstrate that unique quantum phenomena can be achieved in graphene QDs due to the interplay between quantum confinement, relativistic quantum phenomena, and non-trivial band geometrical properties.

Cover page of Essays on Belief-Updating and Decision-Making in Financial Markets

Essays on Belief-Updating and Decision-Making in Financial Markets

(2023)

This dissertation contains three essays broadly related to financial markets, with an emphasis on decision-makers’ belief-updating and decision-making.

Chapter 1 studies subjects’ belief-updating when they face an uncertain event accompanied by two independent signals in the laboratory. The “Average model” is introduced and compared with other important models for the goodness off fit. At theindividual level, the results are mixed. Some subjects behave close to one of the model’s predictions, while some behave close to another model’s predictions. The average model outperforms the Bayesian model at the aggregate level in predicting subjects’ posterior beliefs. No clear evidence indicates that subjects’ posterior beliefs converge to the Average or Bayesian model’s predictions over time.

Chapter 2 studies the impact of motivated beliefs, the phenomenon that people believe what they want to believe, on market performance in a laboratory market for a state-contingent common value asset. Motivated beliefs are induced so that traders have polarized preferences over the states. The main findings are that (i) these induced motivated beliefs do not have a significant impact on overall market efficiency, but (ii) they do impact traders’ final asset holdings and belief updating processes, and (iii) the induced polarization persists after receiving private signals and trading in the market. Other findings suggest that a more intense financial stake might improve market efficiency. The induced ego-relevant motivation is significantly stronger than the homegrown motivation to believe in higher payoffs.

In Chapter 3, joint work with Daniel Friedman and Thomas Bowen, we study the impact of traders’ overconfidence on market performance. How does trader overconfidence (judgemental or self-enhancement) affect their performance in asset markets, and overall market quality? Conversely, how does market participation affect traders’ overconfidence? To address such questions, we build a laboratory asset market in which human participants receive private information of varying precision and then trade an asset that pays a single state-contingent dividend. Among other results, we find that greater trader overconfidence can improve price efficiency in some environments, but not in the most realistic environment with experienced traders and ambiguous mixed information precision. In that environment, overconfidence reduces trader profits. We detect no substantial impact of market exposure on trader overconfidence.

Cover page of Trans Stories, Trans Lives: Immersive Theater and its Application in Transgender Storytelling

Trans Stories, Trans Lives: Immersive Theater and its Application in Transgender Storytelling

(2023)

Trans people have been consistently maligned by portrayals of transgender life in popular media. The few good pieces of representation all have one thing in common, they let trans voices speak about trans experiences. In this thesis I will demonstrate the usefulness of Immersive theater as an avenue of trans storytelling by presenting the sociopolitical climate that trans people are facing everyday, and particularly at the time of writing this, including the conservative political attempt to scapegoat us and legislate us out of existence. I will show and analyze the culture of derisive representation that has plagued popular media for decades. Through my project Adri’s Room I hope to show that the form of immersive theater is especially well suited to telling trans stories, as it gives a voice to the internal self and allows the participants a cohesive, intimate view into worlds they may never encounter in their everyday lives. Additionally I will provide details of the production and attempt to demonstrate my methods and reasoning to provide the reader with as much information as possible to assist in the creation of works like this in the future.

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