UC Santa Barbara

Atmospheric acoustic signals produced by crashing ocean waves may be highly variable from sub-hourly to seasonal time scales. Specifically, low-frequency acoustics (below 20 Hz) known as infrasound have been reported near coastlines under variable ocean conditions such as significant wave height, wave period, swell direction, locations of crashing surf, and style of breakers (e.g., Garcés et al. [2003], Aucan et al. [2006], Le Pichon et al. [2004]). Here, we use infrasound and seismic data collected at Coal Oil Point Reserve in Santa Barbara, California, to investigate how the ambient acoustic wave-field is perturbed by variable surf and ocean conditions. Data collection involved one principal infrasound sensor (September 2022–July 2023), complemented by four temporary infrasound arrays of varying geometries: 1) January 11, 2023; 2) January 12–19, 2023; 3) July 10, 2023; 4) October 17–23, 2023. Each array included video recordings, and the latter two arrays involved broadband seismometers as well. We find that distinct groups of surf infrasound signals are produced throughout 10 months of data, and that the amplitudes of these signals are correlated with offshore significant wave height and local wind speed. We estimate source locations of surf infrasound using array-based and network-based processing methods and find a correspondence with expected locations of breaking waves as seen in video footage. We highlight the opportunity to monitor the littoral sea surface state using infrasound and seismic records.

This dissertation evaluates the William Sheppard Collection of African Art at Hampton University. Assembled by Sheppard, a Black missionary to the Congo from 1890 to 1910, this collection comprises the oldest example of Kuba art in the United States and among the oldest intentionally assembled collections of African art outside of that continent. Unlike African artworks that were displayed in predominantly white institutional contexts, the Sheppard Collection is noteworthy for its early acquisition by an institution with a majority Black audience: the campus museum of the Hampton Institute, a historically Black college. The first primary audience for Sheppard’s exceptional collection of African art were students of the Hampton Institute. In that singular context, the works from the Sheppard Collection functioned as object lessons, a type of visual pedagogy that encouraged learning based on observation and experience from direct contact with an object or work of art. This teaching method presupposed a connection between the material world and moral development. Therefore, this dissertation argues that the Sheppard Collection constituted a visible and tangible basis for African Americans to establish a cultural connection to Africa, resonating with the contemporaneous intellectual pursuit of African Americans. Object Lessons: The Hampton University Sheppard Collection of African Art approaches the Sheppard Collection from a diasporic lens. Locating William Sheppard and the Sheppard Collection within African diaspora frameworks, I evaluate the implications of artworks in the Sheppard Collection for the analysis of race and representation in the United States, and the utilization of the Hampton collection in performance and pedagogy.

Through analyses of dramatic performance, collections histories, photography, and the paradigms and protocols of museum display, this dissertation contributes to knowledge of the African diaspora, Atlantic world relations, art at historically Black colleges and the history of modern art and architecture. In the context of a historically Black college, the artworks of the Sheppard Collection took on different meanings from their original contexts. Like the African peoples who were forcibly enslaved and relocated to various places around the Atlantic, these cultural objects carry histories and memories with them. I analyze the Sheppard Collection according to this paradigm and evaluate its artworks as cultural objects that perform diaspora over centuries of Atlantic world relations.

The dictatorship of General Augusto Pinochet (1973-1990) has left a prominent and polarizing mark on the national memory of Chile. Thirty-three years after the return to democracy, the nation has diverging ideas on how to remember this period. In 2023, as I am writing this thesis, an entire generation has grown up in democratic Chile and personal memories of the military government and the violent coup d’état have begun to fade. In this context, the system of national education becomes a key resource for younger generations to develop and understanding of the history that shapes their present-day lives. After Pinochet was removed from power via plebiscite in 1990 and the first civilian-President inherited the administration, the nation underwent a series of changes. Many of these changes focused on the denouncing of human rights violations which took place during the dictatorship and forging a way forward. There was a notable rise in activism and public interest in this period. Chileans were demanding both truth and justice for the abuses committed by the state during the dictatorship. In this atmosphere of activism and openness, a distinct memory movement is born in Chile, echoing similar conversations taking place across Latin America and in other “transitional” states. The memory movement in Chile specifically fights against the objective of oblivion surrounding the Pinochet years. Many of those fighting for the memory are those who will never be able to forget the traumatic cost of dictatorship; they are the family members and loved ones of those who were tortured, disappeared, or exiled during the dictatorship. These familiares-activistas were also incredibly influential in defeating Pinochet in the 1989 plebiscite. After decades of governments from the left (center) political coalition, La Concertación, the Chilean right gained political ground for the first time since the dictatorship with the presidential election of Sebastián Piñera in 2010 and again in 2018. Under the Piñera administration, I argue, the politics of memory shifted. From the memory narratives established by activists and the governments of Concertación leaders, Piñera’s ministers worked to promote a vague narrative of the dictatorship years. Such a narrative distances specific actors and removes some culpability of the military and right-wing politicians. Thirty some years after the return to democracy and after years of the state promoting ideals of compromiso y conviviencia, present-day memory politics in Chile highlight the continuing and deepening polarization of the country.

This thesis will argue that the Chilean state uses the public education system to continually readjust the portrayal of the memory of the Pinochet dictatorship to match or combat political trends. During the alternating presidencies of Michelle Bachelet (2006-2010, 2014-2018) and Sebastián Piñera (2010-2014, 2018-2022), each administration used K-12 education to promote and promulgate a specific vision of the dictatorship that corresponded with their parties’ political and memorial goals.  

Nitrogen-vacancy(NV) centers in diamonds are a prominent example of solid-state spin qubits for applications in quantum information. However, the assembly of solid-state spins, including NVs or auxiliary spins near the diamond surface, with a controlled nanoscale spatial precision remains an outstanding challenge. Consequently, the pathway towards scaling up both quantum simulation and entanglement-enhanced sensing using NVs remains unclear. Furthermore, near-surface NVs tend to exhibit degraded properties, including spin coherence and charge state stability. Firstly, we will discuss the charge state instabilities of shallow NVs. We discover that the charge state stability depends on the local discrete environment, and our observation is consistent with a model of a single electron trap near the NV center. We also discuss protocols that can be used to alleviate the charge state effect on NV measurement. Secondly, we will discuss the utilization of entanglement with auxiliary reporter spins to improve the sensitivity of T1 relaxometry. Thirdly, we will discuss two methods to engineer two-dimensional NV ensembles and the decoherence dynamics due to the many-body noise in such strongly interacting dipolar spin systems. Lastly, we will present our recent progress, where we combine a DNA-based patterning technique with nitrogen-vacancy (NV) quantum sensors in diamond to sense two-dimensional arrays of molecular spins programmably patterned via a monolayer of DNA origami on a diamond surface. We control the spacing of chelated Gd3+ spins down to 6 nm precision and verify this control by observing a linear relationship between proximal NVs’ T1 relaxation rate and the designated number of Gd3+ spins per origami unit. We confirm the preservation of the charge state and spin coherence of the proximal, shallow NV centers and discuss ongoing work towards probing ordered, strongly interacting two-dimensional spin networks on the diamond surface.

Additive Manufacturing, also commonly known as 3D Printing, has significant potential for personalized medicine and biomedical devices, owing to its streamlined design-to-production workflow. Unlike traditional manufacturing techniques, 3D printing allows for the creation of highly tailored products that can be precisely designed to meet the specific needs of individual patients. Current printable biomaterials are limited to synthetic and biological polymers and their range in material properties. Although synthetic polymers are tunable, they lack degradability. Unlike synthetic polymers, biopolymers are biodegradable, but their properties are limited to those found in nature. Therefore, there is a need for tunable and biodegradable materials in 3D printing to help expand its capability. In Chapter 1, the 3D printing hydrogel literature is surveyed, and polypeptides based on N-carboxyanhydride (NCA) are recognized as a potential feedstock that can diversify the printable material palette. In Chapter 2 and Appendix A, a library of star block copolypeptide composed of a consistent inner hydrophilic block and different β-sheet outer blocks were synthesized. By varying the β-sheet forming domains, shear-processable hydrogels with diverse microstructure and mechanical properties were prepared and structure-function relationships were determined. The versatile synthesis of these star block copolypeptides provides a robust platform to tune material properties based solely on molecular design. Utilizing these systems in 3D printing, specifically Direct Ink Writing (DIW), eliminates the necessity for additives and provides a synthetic handle to tailor its functionality. In Chapter 3 and Appendix B, photocrosslinkable groups were facilely integrated into the star block copolypeptide scaffold to allow subsequent chemical crosslinking with visible light after DIW. Escherichia Coli was integrated into these hydrogel inks and biological composites with complex geometries were achieved in these bioinert printing conditions. Furthermore, the tunable properties of different copolypeptide networks enable control over proliferation and colony formation for embedded microbes as demonstrated based on green fluorescent protein (GFP) expression. Opening the possibility of controlling integrated biological behavior through the molecular design of the star copolypeptide matrix. To demonstrate the ease of use of these star copolypeptides, Chapter 4 and Appendix C delve into their utilization as rheological modifiers within the widely used Gelatin Methacrylamide (GelMA) bioinks. The temperature stability of the star copolypeptide networks allows these GelMA hybrids to be extruded at physiological temperatures, facilitating their utilization for integrating mammalian cells for bioprinting. In contrast to conventional rheological modifiers, the star copolypeptide participates in photochemical crosslinking with GelMA while preserving its natural biodegradability. This approach, employing star copolypeptides as rheological modifiers for DIW, showcases the prospective integration of bioactive materials and fluids, paving the way for modular bioinks. This thesis aims to unveil the unexplored capabilities of star copolypeptides as a tailorable material, propelling the frontier of bioprinting.

The present investigation aims to identify best practices to design virtual reality (VR) story-worlds to promote prejudice reduction and foster prosocial attitudes toward under-represented groups. Past research shows that VR, which allows the simulation of scenarios that would otherwise be prohibitively difficult or impossible in real life, can be an effective tool for understanding human cognition and researching perception, decision-making, and behavior (Groom, Bailenson, Nass, 2009). In tightly controlled immersive digital simulations, one can inhabit an avatar’s digital body with salient features (different skin color, age, gender, social status) to trigger beliefs, affect, and behaviors different from normal day-to-day life (Bailenson &Yee, 2007). VR perspective-taking experiences focused on imagined intergroup contact with individuals from marginalized groups can increase prosocial behavior toward them (van Loon, Bailenson, Zaki, Bostick, Willer 2018). Intergroup contact theory hypothesizes that reducing anxiety, which is the cause of increased stereotyping against the outgroup, and permeating the social encounter with positive emotions (Miller, Smith, & Mackie, 2004) leads to prejudice mitigation (Pettigrew & Tropp, 2006). Beyond these insights from social psychology, sparse literature has explored how to design immersive story-worlds to instill prosocial attitudes and behaviors, including the effectiveness of employing photorealistic techniques. This research fills this gap and challenges the assumption that human perceptions inside virtual and physical worlds are equal if digital assets are photorealistic. By creating a taxonomy of design strategies for inclusive VR, displaying data gathered during playtesting six state-of-the-art VR experiences, it identifies which affordances and methodologies are significant to inducing compassion and prosocial attitudes in immersive social encounters and contributes a pragmatic approach to the design of VR for bias mitigation while considering the craft, ethical and humanistic dimensions of the medium.

Small-scale fisheries (SSFs) are critical to global food security, livelihoods, and cultural heritage. As one of the oldest forms of wild harvesting, SSFs can support sustainable practices through the self-organization of fishers. Yet, global market integration and environmental change reshape fishers’ incentives, influencing behaviors like cooperation and coping. Understanding and quantifying these behaviors is key to fostering the sustainability and resilience of SSFs. I employ social science methods to investigate cooperation and coping in SSFs quantitatively. In my first chapter, I apply experimental economics to investigate the impact of game experiment designs on measurements of cooperation levels among fisher groups in real-world settings. My second chapter presents a nationwide evaluation of a fisheries co-management policy in Chile, implemented more than two decades ago, to encourage cooperative and sustainable practices among fishing communities. I assess the survival of co-management projects as a measure of success and study its variability across social and ecological conditions. In my third chapter, I study coping responses to fisheries closures triggered by harmful algal blooms in Southern Chile. Using econometric methods, I analyze fishers’ mobility across resources and space, and the influence of market dynamics and management regulations. My research seeks to contribute to more informed and effective fisheries management that considers the complex interplay of incentives, behaviors, and policy outcomes in SSFs.

My dissertation titled Native ways of knowing: Navigating life as a transracial adoptee is anautoethnography of my experience in coming to understand my childhood and schooling experiences as a Native adoptee who grew up in a white family in Alberta Canada. I highlight my journey in coming to learn about my Native roots as well as unpacking experiences with various institutions, including primary, secondary and university schools’ systems, all of which represent ways of learning that exclude Native ways of knowing. I view this dissertation as a way of regaining what has been long denied centering on Native ways of knowing, and integrating teachings from my biological family members, particularly my aunt uncle who invited me to the Siksika Nation located in southern Alberta. I begin this thesis with an introduction to the reader as a participant in what is called a talking circle. A talking circle is a healing space for members to connect with Creator and share challenges and emotional wounds in a way that allows one to let go and replenish one’s soul and voice. I welcome the reader into my virtual teepee, and begin with a traditional smudging ceremony, all of which is visually illustrated through my artwork. As such, art is a throughline vi for this dissertation; I can best clarify meaning through art, which is a shared skill among members of my biological family who engage in a variety of crafts–beadwork, tapestries, painting, and the like. I come from a long line of artists and as such, the artwork presented throughout this thesis is a crucial component of my story. Following the practices of Native scholars like Kimmerer (2013) and Archibald (2008), I tell my journey about coming to understand my transracial identity through an approach that reflects values centered on the natural world that communicates with us if we have the ears to hear. The flow of my story work begins with establishing the talking circle (Grounding), then moves to my understanding of scholarship about and by Native communities (Native Ways of Knowing and Being), and how who authors such work makes a big difference in how the Native lens of knowing and being is represented. Then, I tell the reader about my own story (My Journey) about how I came to know my native roots, and how no matter how long it takes, it is never too late to cultivate connections to one’s roots. I end my talking circle with note of hope and care for all with experiences similar to mine (Onward), that while not all of us have, or will have the same opportunities to connect with our Native roots, and we represent a broad range of cultural identities, often a mix of ethnicities that should be celebrated.

This dissertation investigates the prominence of incest tropes in Australian and U.S. Rural Gothic literature and film of the late nineteenth through early twenty-first century. Through a comparative study of texts from and about Tasmania and Appalachia, regions of low-economic status historically imagined to be on the fringe of their respective nations, I trace how stereotypes about inbreeding among the white rural poor reflect an anxiety over state biopower that originated during the founding of these settler colonies. I argue that the fear of “failed” yeoman farmers, whose non-normative sexuality, gender, racial identity, and refusal of labor are understood to degrade the settlement from within, led to the creation of an “inbred” hillbilly figure that can be found throughout the media of settler colonial states. I coin the term “inbred grotesque” to refer to the aesthetic pattern associated with this stock character, whose prominent physical differences, deformities, and disabilities are designed to reflect their internal opposition to settler values. I examine how the inbred grotesque transformed incest into a form of cultural shorthand for alternative and queer kinship patterns that challenge the foundational unit of settler states—the patriarchal nuclear family. Throughout the dissertation, I outline how the hillbilly and inbred grotesque shaped and were shaped by eugenic theory, industrialization, and nationalist movements.

In the first and second chapters, I focus on the literary and historical origins of incest stereotypes in Appalachia and Tasmania, taking as my primary case studies John Fox Jr.’s Virginian “local color” novel The Trail of the Lonesome Pine (1908) and Marcus Clarke’s Van Diemonian convict narrative For the Term of His Natural Life (1874). In my third chapter, I perform a comparative reading of Cormac McCarthy’s novel Outer Dark (1968) and Louis Nowra’s play The Golden Age (1985), examining how these American and Australian writers harnessed the inbred grotesque to express their opposition to postmodernist challenges to reproductive futurism. In my fourth chapter, I move to the birth of the “killbilly” horror genre, the dominant form of the inbred grotesque from the 1970s to the present day, and consider how cult films featuring inbred cannibal families such as The Texas Chain Saw Massacre (1974), The Hills Have Eyes (1977), and House of 1000 Corpses (2003) have both sustained and challenged hillbilly tropes. Finally, in my epilogue, I discuss the fate of the hillbilly today, considering how this figure has played a key role in the rhetoric of the contemporary Australian and American far- and alt-right movements and how the Left might itself learn to embrace the inbred grotesque.

The flow of suspensions of particles in confined systems is ubiquitous in both natural and industrial contexts, ranging from extrusion-based additive manufacturing to water infiltration in soil. However, characterizing and modeling the underlying physics, especially when the size of a constriction is similar to that of the suspended particles, remains a challenge. This PhD work has considered the interplay of particles with two distinct types of confinements featuring: soft and hard.

Soft confinements refer to deformable liquid-air interfaces, such as the ones involved in coating processes. Two processes sharing common features are considered: withdrawing a suspension from a capillary tube, leaving a thin film on the inner wall, and dip-coating, which consists of pulling a solid substrate out of a suspension bath to deposit a thin coating film on the surface. It is demonstrated that the stagnation point at the liquid-air meniscus acts as a tunable "filter" that governs the thickness of the coating film. The local thickness controls whether particles of a certain size will be deposited in the film or repelled back to the suspension bath. The deposition threshold of single spherical and anisotropic particles is investigated, and based on these findings, a filtration method for sorting particles of various sizes and guidelines for controlling the composition of the suspension film are proposed.

The discussion then shifts to the flow of suspension through hard confinements in millifluidic channels, where particles are confined within solid walls. The research focuses on the clogging mechanism known as bridging, where particles of a size comparable to the constriction form a stable arch, blocking the channel and prevent further particle transport. Through experimental investigations, the influence of the geometry of the constriction, including its size and angle, on the particle throughput before the formation of a clog is characterized. Additionally, unique clogging phenomena observed in three-dimensional systems are explored.