VictorJuiz/thesis huggingface dataset:
Polyfolds and Persistence

This thesis contains polyfold constructions with applications to symplectic topology, as well as Künneth formulas for persistent homology of various filtrations with applications to Topological Data Analysis./nIn symplectic topology, we provide a polyfold version of the Piunikhin-Salamon-Schwarz proof of the Arnold conjecture -- our proof holds for general closed symplectic manifolds. This proof relies on the polyfold regularization of moduli spaces with a finite dimensional constraint imposed on evaluation maps, for which we provide multiple polyfold constructions that can be applied as black boxes in general situations. One of these black boxes can be viewed as an implicit function theorem: we construct a polyfold structure on the subset of a polyfold cut out by a submersive finite dimensional constraint, and then we prove the sc-Fredholm property for the restriction of a sc-Fredholm section to this subset. We go on to further investigate when an implicit function theorem holds in polyfold theory: We give explicit counterexamples to a general implicit function theorem for sc-smooth maps, and we show how the novel notion of a sc-Fredholm map overcomes this difficulty, justifying the technical complexity of polyfold theory./nIn Topological Data Analysis, we prove a Künneth formula in low homological dimensions for the persistent homology of a Cartesian product of finite metric spaces equipped with the sum metric. In all homological dimensions, we bound the interleaving distance between the prediction from the Künneth formula and the true persistent homology. As preliminary results of independent interest, we prove Künneth formulas in all homological dimensions for the persistent homology of the Cartesian product of R_+-filtered simplicial sets and also for the homology of the graded tensor product of simplicial k[R_+]-modules.

Advisor: Wehrheim, Katrin
Between Noise and Song: The Contested Voice in Opera after Wagner

This project argues that changes to operatic vocal writing in the late nineteenth century prompted Austro-German operagoers to radically expand their understandings of vocal sound in the years around 1900. As post-Wagnerian composers granted greater melodic expression to the orchestra, and increasingly exploited non-melodic vocal effects such as groans and cries, fierce debates were launched about what and how opera’s voices ought to communicate. I track the fallout from these developments, drawing on an archive of journalistic music criticism, vocal treatises, and singer memoirs, as well as under-examined sources such as letters to newspapers, satire, poetry, and cartoons. Listeners looked far beyond the theater to interpret the shifting vocal terrain, enlisting operatic voices in such urgent fin-de-siècle projects as the fortification of human agency amidst industrial creep and the development of a middle-class resistance to elite aesthetics. By showing how they used operatic voices to comprehend and to construct the world around them—especially through emerging, abstract notions of “voice”—I not only provide new examples of the ways in which musical experiences can condition political thought, but reveal several new dimensions to the role of opera in sociopolitical change.

Advisor: Smart, Mary Ann
Cleanliness and Civilization: Public Health and the Making of Modern Japan and Korea, 1868-1910

In the late nineteenth century, a global revolution in the practice of health impinged upon Korea and Japan. New understandings about the causes and spread of disease played a formative role in the modernization of both countries. Through the medium of public health—the science and practice of disease prevention and prolonging life—the Japanese and Korean governments sought to harness and manipulate a host of new technologies so as to engender fealty to the nation and mobilize populations on behalf of the state. For Japan, public health also became the foremost means of perpetuating and justifying imperial expansion. For Korea, public health functioned as a vehicle for preserving territorial sovereignty. And for both countries, the discipline became a barometer whereby Korean and Japanese leaders measured levels of national “progress” against the world and each other./nDrawing from archival materials housed in three countries, this dissertation uses public health in order to critically reexamine the making of modern state-society relations in Japan and Korea, and the relationship between these two countries. I argue that public health functioned as a way of internally strengthening somatic control over populations while externally broadcasting the nation’s achievement of a higher level of civilization./nIn the 1870s and 1880s, medically-minded intellectuals and bureaucrats in Korea and Japan held similar visions of “hygienic modernity,” or the condition whereby the health of populations connoted national strength and civilizational advancement. Implementing and showcasing the adoption of supposedly universal and normative standards of clean behavior would, it was thought, convince Western imperial powers that Japan and Korea were their equal. In an effort to “heal the nation,” these elites issued laws, penned editorials and delivered popular lectures designed to reform everyday health praxis. Oftentimes for these reformers, the ability to exhibit improvements in health—whether through urban beautification programs, reforming bodily comportment, or the construction of grand medical facilities—mattered more than the elimination or prevention of disease. I refer to this act of displaying hygiene as cleanliness, or a condition whereby the home, the body, and the state all transformed so as to convince foreign and domestic audiences of the nation’s teleological progress./nBy taking an integrative and comparative approach to the history of Korea and Japan, this project also attempts to broaden the analytical frames through which these two histories have traditionally been examined. My study calls attention to the relationship between anti-disease measures, struggles over sovereignty, and how health reforms helped shape notions of national belonging. Most fundamentally, my project helps re-integrate the modern histories of Korea and Japan—two fields frequently conceived in exclusively national terms—into both a broader regional context as well as into the larger history of the early twentieth century world.

Advisor: Barshay, Andrew E
Adolescent Refugees’ Judgments of Harm in War and Resettlement Contexts

Protracted wars in the Middle East have forced millions of people to flee and resettle in Western countries. Adolescents might be most affected by their war and resettlement experiences, yet have received limited attention in developmental research. The purpose of the current study was to determine how younger (12-14-year-olds) and older (17-19-year-olds) adolescent refugees from Syria make judgments about harm in unprovoked and provoked situational contexts. Fifty-nine newcomer Syrian adolescent refugees (30 boys and 29 girls) living in Canada were interviewed about straightforward and complex situations involving harm (i.e., hitting). All participants provided negative evaluations of harm in response to general questions and almost all stated that there should be a law against hitting. The majority of evaluations were stable, meaning not contingent on parental authority, school rules, or common societal practice. All participants in the baseline (unprovoked) condition, and almost all participants in the survival condition provided negative evaluations of harm in Syrian war and Canadian resettlement contexts. The majority of participants provided negative evaluations of harm in retribution conditions, and a small but significant proportion evaluated harm as less acceptable in the resettlement context than in the war context. Negative evaluations elicited moral justifications (i.e., welfare, equality), whereas positive evaluations elicited nonmoral justifications (i.e., personal, authority/rules, and retaliation). The Canadian resettlement context elicited more authority/rules considerations than did the Syrian war context. Younger adolescents were significantly more likely than older adolescents to justify negative evaluations based on authority/rules. Older adolescents were more likely than younger adolescents to provide mixed evaluations for retribution conditions. Significant gender differences were not found. Cultural considerations, social and educational implications, and future directions are discussed.

Advisor: Turiel, Elliot
Pulsed Laser-induced Light Coupling and Phase Transformation of Silicon Nanostructures

Silicon nanostructures serve as the backbone of modern electronics and photonics. Particularly, silicon nanoresonator became an increasingly important building block for the advanced photonics applications, including sensing, wavefront engineering and integrated photonics. Its crystallinity engineering is critical for enabling the manufacturability as well as fueling the continuous innovation on the device functionalities. Meanwhile, the scalable patterning of such nanostructures could offer cost-effective and highly controllable manufacturing routes beyond the conventional complementary metal-oxide-semiconductor (CMOS) fabrication. Owing to the controllable energy delivery and capability to interact with nanostructures, pulsed laser processing could significantly shed light on the above challenges and opportunities./nThe pulsed laser processing of semiconductor material has been intensely investigated in the last century providing insights into fundamental light-material interaction. In early this century, thin-film laser processing became the main research topic as the complex coupling of heat transfer and phase transformation has enabled the technical innovation towards thin-film transistors in the display industry. However, when the lateral dimensions of the semiconductor material further shrunk down to the order of 100nm, the governing laws of the multiphysics interaction had to incite a significant paradigm shift in the study of the optical coupling, heat transfer and phase transformations./nThis dissertation focus on understanding new coupling mechanism of pulsed laser interaction with silicon nanostructures, and exploiting them for scalable patterning and crystal engineering of the functional resonator arrays. Based on the unique near-field enhanced optical absorption, we first demonstrate the optically directed assembly of silicon nanoresonators. Spherical silicon nanoresonators can be fabricated with programmable numbers and combinations. Based on the ultrafast quenching rate and high adhesion work of silicon, we then demonstrate the deformation-free reversible phase transformation of silicon resonators that enables the active modulation of visible wavelength metasurfaces. Our in situ reflection probing of a single silicon nanodisk coupled with comprehensive simulations helps to reveal the mechanism behind the amorphization. We believe the experimental probing results lends support to the hypotheses silicon relaxation time scale on the silicon glass transformation. Lastly, through femtosecond laser irradiation, we observed the ultrafast field enhanced selective material removal within nanodisks. The detailed dynamics of the field enhancement, carrier excitation, non-thermal melting and subsequent cold ablation are studied ex-situ and in-situ. The mechanism can be used for scalable manufacturing of bowtie sensing structures and laser printing optical metasurfaces.

Advisor: Grigoropoulos, Costas P
Five Soils and a Letter: profiles in the political ecology of Mexico City

Traditional accounts of Mexico City’s environmental crisis focus on the city’s rapid population explosion in the 20th century. Population based theories of the environmental crisis misdiagnose as 'bios' conditions that are inextricable from the city’s 'geos,' obfuscating the central geological relationships that structure life in the city. In Five Soils, urban and anthropogenic soils are taken up as a lens through which to examine the vertical geopolitics of the larger Mexico City-Mezquital Valley system. Each these five soils reveals something crucial about the politics and epistemologies that shape our understanding of urban ground.

Advisor: Kosek, Jake
Watts, Michael
Chemical Imaging and Proteomics Approaches for Probing Copper and Histidine Biology

Chemistry provides valuable tools to probe and influence the molecular processes in biology. Such processes are made available by both large biomolecules and small molecule species. As an example of a transition metal nutrient, copper plays essential roles in respiration, electron transfer, antioxidant defense and oxidation of metabolites, while aberrant copper homeostasis occurs with severe diseases states including neurodegenerative disorders, diabetes and cancer. On the other side, proteins, as large biomolecules, are composed of simple amino acid building blocks. Histidine is an important amino acid, with its imidazole side chain frequently used at catalytic centers and metal-binding sites. This dissertation summarizes my efforts to probing copper and histidine in their biology contexts. Specifically, a series of copper fluorescent sensors with varying colors were designed for visualizing this metal in cells. For probing histidine, we firstly developed bio-inspired thiophosphorodichloridate reagents for its chemoselective labeling on proteins. The labeling of this amino acid provides a starting point for probing histidine by proteomics methodology. Further optimization of the reagents as well as the protocol enables the profiling of histidine in a proteome context.

Advisor: Chang, Christopher J.
Spin-Orbit Torques in Ferrimagnets and Topological Insulators

In the field of spintronics, the transport of spin and charge is explored. Within the last decade, significant progress has been made towards the understanding of spin-charge coupling in metallic systems. Further, novel spintronic device applications have been realized. In this regard, spin-orbit torque is of particular interest, as it enables the manipulation of magnetic ordering and has been proven to be useful for memory and logic applications. Here, spin-orbit torque describes the generation of a pure spin current via the spin-Hall effect in a heavy metal or the Rashba-Edelstein effect in a heavy metal\slash ferromagnet interface. When the spin-current diffuses into an adjacent ferromagnet, the magnet generally experiences a torque and thus magnetization dynamics is excited./nIn this thesis, we investigate spin-orbit torque in transition metal-rare earth ferrimagnets. While these ferrimagnets provide technological advantages compared to ferromagnets, such as magnetization tunability and bulk perpendicular magnetic anisotropy, the angular momentum transfer process has not been well understood. We show that the spin-orbit torque driven angular momentum transfer follows the sign of the total magnetization, while transport-based effects such as the anomalous Hall effect are only sensitive to the transition metal magnetization. Further, we demonstrate the spin-orbit torque switching of ultra-thick GdFeCo films and show that GdFeCo is a promising material for magnetic memory devices due to a high spin-orbit torque switching efficiency j_c/\Delta./nIn the second part of this thesis, we study spin-orbit torques in topological insulator\slash ferromagnet heterostructures. To this end, harmonic Hall measurements are performed in BiSb\Co heterostructures. We find a large second harmonic voltage response stemming from the ordinary Nernst effect, while signatures of spin-orbit torque are absent. This is in contrast to a recent report in literature reporting spin-Hall angles significantly larger than unity. We conclude that the ordinary Nernst effect can be a spurious signal in harmonic Hall measurements where the in-plane magnetic field is rotated in the film plane./nThe third part of this thesis discusses the influence of mechanical stress on the performance of magnetic tunnel junctions for spin-transfer torque magnetic random access memory. To this end, a 4-point bending setup that allows the application of constant stress over a large substrate area is developed. We find that the performance of the magnetic tunnel junctions is very robust to external stress with changes in tunnel magneto-resistance (TMR), switching current I_c, and thermal stability Delta less than 2 %.

Advisor: Salahuddin, Sayeef
Hellman, Frances
Hierarchical Assemblies in Supramolecular Nanocomposite Thin Films: Kinetic Pathway Dependence

Polymer nanocomposites are an extremely versatile class of materials due to the variety of materials that can be used and their many applications. Structured nanocomposites are of particular interest due to the potential of a structure/function relationship. In order to establish such a relationship, a variety of nanoscale structures with control over how to generate them. Block copolymer (BCP)-based supramolecules have been studied for the past two decades in thin film due to their ability to self-assemble to form order on the nanoscale. The complexity of supramolecules is obvious: they are constructed from noncovalently attaching a small molecule to a BCP block. As a multicomponent system, the self-assembly process is governed by competing thermodynamic and kinetic considerations. The thermodynamics that lead to equilibrium structures are well understood. In order to move beyond known structures and create tunable thin films, the kinetic pathway must studied./nThe effect of several parameters in the multicomponent system on the final film structure and long-range order was quantified to understand the synergistic effects of the components. A multi-dimension diagram of the assembly process was developed that accounts for experimental observations in supramolecular thin films in the last decades from multiple groups. This diagram was used to create a design framework that can be used to control the long-range order in nanocomposite thin films by controlling the kinetic pathway./nThe framework determined was applied to lithographically patterned substrates to achieve assemblies under incommensurate conditions that aligned with circular patterns. The resultant structures arise from the kinetic pathway during assembly rather than purely thermodynamic considerations./nA different kinetic regime was explored by using high molecular weight-based supramolecules. These films have two distinct kinetic regimes: slow diffusion of highly entangled polymers and the relatively faster diffusion of nanoparticles. The two regimes can be modulated so that films with different structure and feature sizes can be achieved. In situ grazing-incidence transmission small angle X-ray scattering studies were performed to monitor the kinetic pathway taken during self-assembly to quantify the changes to structure and order in a solution-based process. The information about the importance of the kinetic pathway on a multicomponent system yielded a deeper understanding of the assembly process that opens the door to creating designer nanocomposites with precisely tailorable features.

Advisor: Xu, Ting
Some New Directions in Spectroscopy

The work presented in this thesis comprised two major projects. The first, a spectroscopic study of water clusters in the Terahertz vibrational region revealed a dramatic enhancement of tunneling motions involved in breaking and reforming hydrogen bonds. The second project involved constructing a second harmonic scattering (SHS) experiment which was used to probe buried interfaces./nThe study of water clusters provides a useful route towards unraveling the many body terms of the water potential. High-resolution vibrational-rotational-tunneling (VRT) spectroscopy is a particular sensitive measure of the repulsive walls of the water potential. While this method is extremely powerful, the major challenge is assigning the complex spectra that is output from the experiment. To that end, the major contribution of this thesis is an automated pattern matching algorithm based on the symmetric-top, rigid rotor model. Using this algorithm, transitions of the water dimer, pentamer, hexamer, and octamer were identified and assigned from a back log of experimental data. These assignments revealed a dramatic enhancement of tunneling motions in the librational (300 – 600 cm-1) region. These enhancements were most dramatic for motions involved in breaking and reforming the hydrogen bond in the clusters, adding to the evidence that understanding this region is essential to understanding hydrogen bond breaking dynamics./nThe use of 2nd order, nonlinear spectroscopy to probe surfaces is a well-established technique. Employing second harmonic generation in a scattering geometry enables probing buried interfaces in colloidal samples; these samples provide an appealing path forward towards studying real world polymers such as water purification membranes. We show that SHS can be used to probe resonant and non-resonant molecules at a polymer interface, and we extract free energies of adsorption from a variety of organic molecules. In the future, we plan to extend this technique to ionic species to supplement our existing studies of ion adsorption via sum frequency generation in reflection geometry.

Advisor: Saykally, Richard J
The effects of mitochondrial stress on organismal health in C. elegans

Mitochondria are an essential organelle, serving as a key site of energy production in metazoans. Animals have complex systems for monitoring the health and proteostasis of mitochondria, and activate multiple quality control mechanisms in response to dysfunction. Using the nematode Caenorhabditis elegans, we investigated mitochondrial health, dysfunction, and stress signaling in two different systems./nDysfunction of mitochondrial DNA replication machinery is a common cause of mitochondrial diseases. The minimal mammalian replisome is made up of DNA polymerase gamma, replicative helicase Twinkle, and single-stranded DNA binding protein. Recently, a sequence homolog of Twinkle was uncovered in the nematode C. elegans. Here, we characterized this homolog, twnk-1, and report that while twnk-1 does not appear function as the primary mitochondrial DNA replicative helicase in this species, as loss of twnk-1 does not result in reduce mitochondrial DNA levels, or result in other expected mitochondrial dysfunctions such as reduced oxygen consumption rates, increased sensitivity to metabolic perturbations, or reduced muscle function. However, twnk-1 mutants exhibit phenotypes associated with mitochondrial stress, including reduced fecundity, an activation of the mitochondrial unfolded protein response (UPRmt), and mitochondrial fragmentation. Our results suggest that in C. elegans, twnk-1 does not function as the mitochondrial DNA replicative helicase, but has an alternative function in regulating mitochondrial function./nIn a second project, we focused on the UPRmt, a transcriptional program initiated when mitochondrial proteostasis is challenged. Previous work from our lab shows that when mitochondrial health is challenged in neurons alone, they signal to distal tissues, activating the UPRmt in the intestine. This causes hormesis as shown through extended lifespan. We found that when the UPRmt component and chromatin modifier PHF8/jmjd-1.2a is overexpressed in a second neural cell type, astrocyte-like cephalic sheath glia, they signal the UPRmt to distal tissues as well. We used two UPRmt reporters to investigate this effect, and to dissect the details of the two branches of UPRmt signaling. Glial UPRmt induced hormesis as shown through extended lifespan, as well as resistance to the mitochondrial stressor paraquat. This work contributes to the growing field of glia biology and supports the hypothesis that glia are actively involved in information processing and signaling.

Advisor: Dillin, Andrew