VictorJuiz/thesis huggingface dataset:
A Magnetic Resonance Perspective of Adsorbates Motion in Metal Organic Frameworks

One of the most promising novel materials being developed is a type of nanoporous/nmedia referred to as Metal Organic Frameworks (MOFS). MOFs can be/nenvisioned as Tinker Toys(TM), with inorganic paddle wheels and organic connecting/nsticks. MOFs are a novel type of porous materials that have shown unprecedented/nstorage capacities, separation selectivity, and chemical reactivity as solid catalysts./nThese attributes are further enriched by the modularity of MOF structures, including/nthe ability to tune geometry (pore size), topology (pore shape(s)), chemical anity/n(linker design), and reactivity (metal coordination chemistry). This diverse array of/napplications requires a thorough understanding of MOF-adsorbate interactions in/na wide range of thermodynamically diverse operating conditions. Although there/nare many macroscopic techniques available to researchers, very few techniques can/nprobe the relevant times (ns) and length scales (nm) of the molecular interactions/nthat contribute to the overall performance MOF materials. I have chosen to use/nNuclear Magnetic Resonance (NMR) to probe these interactions because NMR is/na non-destructive tool that can access in-situ molecular motion and energetics at/nthese time and length scales, while minimizing the amount MOF needed (mg). The/nNMR observables (i.e. trends in longitudinal relaxation, transverse relaxations, selfdi/nusion coecients, and NMR lineshapes and crystal orientation studies) at relevant/noperating conditions provide information that when complimented by molecular/nsimulations can be extended to macroscopic material attributes for separations. In/npursuit of these systematic investigations this dissertation includes the construction/nNMR instrumentation to observe the behavior of both liquid and gaseous adsorbents./nCharacterization of the translational motion of xylene molecules in MOF-5 through/nobservation of the self-diusion coecients to develop understanding of motion of/nxylene molecules in isotropic connement. The investigation of these structureproperty/nrelationships via NMR in IRMOFs (iso-reticular MOFs) systems has lead/nto understanding the influence of the open-metal site pore chemistry on molecular/ntransport of methane (CH4) in an IRMOF, M2(dobdc), where M is either the (Mg,/nNi, or Zn) metal. NMR relaxometry conducted on CH4 in this systems suggest a/nlarge dierence in local density causes increase rotational correlations times. Diusive/ndiraction behavior was observed at certain pressures in this family of materials and/na kinetic Monte Carlo program was written in order to interpret the data. Finally, an/ninternational collaboration with the Prof. Blmich at RWTH Aachen was executed in/norder to expand the applicability of magnetic resonance methods for characterizing/ntransport on more prototypical MOFs. These gradients must be considered for/ninterpretation of relaxometry data.

Advisor: Reimer, Jefferey A
Theories and Methods for a Cognitive Macro-Sociology of Culture

This dissertation emerges out of an effort to understand the supra-individual aspects of attitudes and tastes, and especially those political attitudes that make up "public opinion." Various theoretical accounts conceive of large-scale attitude systems in terms of fields, shared schemas, cultural logics, or partisan ideologies. Though diverse, these accounts all depict attitudes as structural phenomena, defined by patterns of relations between cultural, cognitive, or social elements. In the three substantive chapters, I draw on network analysis, statistics, information theory, and computer science to create original methods for such structural analyses. I use them to provide new insights on culture as both individual cognition and macro-scale social organization. The first project examines networks of political attitudes. I find that, across subgroups, attitudes either follow the dominant liberal-conservative logic, or lack systemic organization. In the second project, I clarify and extend existing theories of cultural schemas to develop a greatly improved approach to detecting them in surveys. In the final project, I approach political attitudes as a field of competition. If public opinion is a debate between competing ideological camps, do the camps at least agree on which issues they are debating? My analyses of the skill with which individuals at different positions in the opinion space report their attitudes suggests that no such agreement exists.

Advisor: Fligstein, Neil D.
Willer, Robb
The role of energy reservoirs in distributed computing: Manufacturing, implementing, and optimizing energy storage in energy-autonomous sensor nodes

The world already hosts more internet connected devices than people, and that ratio is only increasing. These devices seamlessly integrate with peoples lives to collect rich data and give immediate feedback about complex systems from business, health care, transportation, and security. As every aspect of global economies integrate distributed computing into their industrial systems and these systems benefit from rich datasets. Managing the power demands of these distributed computers will be paramount to ensure the continued operation of these networks, and is elegantly addressed by including local energy harvesting and storage on a per-node basis. By replacing non-rechargeable batteries with energy harvesting, wireless sensor nodes will increase their lifetimes by an order of magnitude./nThis work investigates the coupling of high power energy storage with energy harvest- ing technologies to power wireless sensor nodes; with sections covering device manufacturing, system integration, and mathematical modeling. First we consider the energy storage mechanism of supercapacitors and batteries, and identify favorable characteristics in both reservoir types. We then discuss experimental methods used to manufacture high power supercapacitors in our labs. We go on to detail the integration of our fabricated devices with collaborating labs to create functional sensor node demonstrations./nWith the practical knowledge gained through in-lab manufacturing and system integration, we build mathematical models to aid in device and system design. First, we model the mechanism of energy storage in porous graphene supercapacitors to aid in component architecture optimization. We then model the operation of entire sensor nodes for the purpose of optimally sizing the energy harvesting and energy reservoir components. In consideration of deploying these sensor nodes in real-world environments, we model the operation of our energy harvesting and power management systems subject to spatially and temporally varying energy availability in order to understand sensor node reliability. Looking to the future, we see an opportunity for further research to implement machine learning algorithms to control the energy resources of distributed computing networks.

Advisor: Wright, Paul K
The Quantum Focussing Condition and Quantum Null Energy Condition

Evidence has been gathering over the decades that spacetime and gravity are best understood as emergent phenomenon, especially in the context of a unified description of quantum mechanics and gravity. The Quantum Focussing Conjecture (QFC) and Quantum Null Energy Condition (QNEC) are two recently-proposed relationships between entropy and geometry, and energy and entropy, respectively, which further strengthen this idea./nIn this thesis, we study the QFC and the QNEC. We prove the QNEC in a variety of contexts, including free field theories on Killing horizons, holographic theories on Killing horizons, and in more general curved spacetimes. We also consider the implications of the QFC and QNEC in asymptotically flat space, where they constrain the information content of gravitational radiation arriving at null infinity, and in AdS/CFT, where they are related to other semiclassical inequalities and properties of boundary-anchored extremal area surfaces. It is shown that the assumption of validity and vacuum-state saturation of the QNEC for regions of flat space defined by smooth cuts of null planes implies a local formula for the modular Hamiltonian of these regions. We also demonstrate that the QFC as originally conjectured can be violated in generic theories in
d
≥
5
, which led the way to an improved formulation subsequently suggested by Stefan Leichenauer.

Advisor: Bousso, Raphael
How Do Pregnant Teenagers Make the Decision to Terminate or Continue? A Study of the Pregnancy Resolution Process Among African-American and White Women Aged 14-20

This dissertation addresses the following questions: 1) How do teenagers decide whether to terminate or continue a pregnancy?, and 2) Why do some pregnant teenagers choose to continue their pregnancies while others do not? I answer these questions using data from 19 months of participant-observation at reproductive health clinics and transcripts from in-depth interviews with 45 pregnant young women made across time as they decided whether to terminate or continue. While some sociologists argue that moral decisions are determined by non-conscious thought, I found that participants used a combination of reason, intuition, imagination, and cultural knowledge to decide which route to take. In addition, cultural meanings of pregnancy and coercive actions of parents and partners constrained individual decision making. Teens made pregnancy resolution decisions through a process of imaginative assessment in which they projected themselves forward into the future. Imaginative assessment involved mentally rehearsing potential scenarios trying to gauge how different futures might look or feel. Thus, participants used cultural knowledge to explore various hypothetical scenarios and to determine, in negotiation with other actors in their environment, which imagined future was most appealing and most likely. Comparing those who continued with those who did not, I argue that two key mechanisms--daily activity level and formulations of the future--explained how it came to be that structural factors influenced decision outcomes. That is, access to educational and employment opportunities, which were evident in teens' daily activities, shaped the futures they imagined inhabiting. Teens with opportunities, who were typically engaged in goal oriented activities, usually felt they were too busy to have a baby and imagined motherhood in negative terms as disruptive of their plans for the upcoming year. In comparison, teens with fewer opportunities who were less engaged in their daily activities, and perhaps unoccupied or bored, imagined the baby as a positive addition to their lives. Teens with fewer opportunities were also more likely to focus on their romantic relationships and hope that the baby would provide the beginnings of an emotionally fulfilling family life--either with or without their boyfriend. Thus, a teen’s daily level of engagement in goal oriented activities directly shaped their ideas about the short term future which, in turn, informed their decision making. My findings contribute to the sociology of morality, theories of reproductive decision making, and recent work on future projections.

Advisor: Swidler, Ann
Mixed Signals: Regulation of host metabolism by an intracellular bacterial pathogen

A hallmark of all pathogens is an ability to acquire nutrients from hosts. In order to do this, pathogens must overcome both the tight regulation of host nutrients and the host defense mechanisms deployed to protect these nutrients./nIn the introductory chapter of this dissertation, I begin with a discussion of innate immunity. I discuss the now appreciated view of the innate immune system as a sensor of patterns of pathogenesis. I then argue, based on our studies in Legionella pneumophila, that nutrient acquisition by microbes is a pattern of pathogenesis./nIn chapter two, I provide experimental evidence that nutrient acquisition is a pattern of pathogenesis. I discuss my work describing how L. pneumophila alters a key metabolic signaling pathway, the mechanistic target of rapamycin complex 1 (mTORC1), in order to free amino acids for nutrition. Using an effector screen, I identified two groups of L. pneumophila Dot-dependent substrates that have opposing consequences on mTORC1. I showed that a family of Legionella glucosyltranferases, Lgt1-3, activate mTORC1 via translation inhibition, resulting in release of host amino acids. These amino acids activate mTORC1 but do so in a counterproductive way: stimulation of mTORC1 leads to the initiation of translation, which consumes the amino acids meant for L. pneumophila. To counter this, L. pneumophila also secretes the SidE family, which inhibits mTORC1 by directly inhibiting the Rag small-GTPases that are required for mTORC1-dependent amino acid sensing. The SidE effectors blind mTORC1 to the amino acids newly freed by the Lgt family. The net result of this battery of SidE and Lgt effectors is to enable L. pneumophila to manipulate the host into liberating amino acids for bacterial consumption./nI then close with a perspective chapter that describes the additional questions my work has given rise to and the state of the bacterial molecular pathogenicity field as a whole.

Advisor: Vance, Russell E
The Crucial Role of Teachers of Latino ELL Students: Enactment of Language Policy in Two Urban High Schools

Through this embedded case study I examine how ELL policy is enacted in two under-resourced high schools where 40% of students are classified as ELL, 90% of whom are Latino. I explore how ELD and Sheltered Instruction teachers perceive and respond to academic and social needs of their students in two different schools in the same district. I analyze how a district that has a language policy that promotes bilingualism and biliteracy plays out in these two schools. Specifically, I detail how policy messages are interpreted and enacted at a district and school level and the interplay of district and school level actors’ beliefs and the various district mandates./nFindings indicate that district and school administrators respond to policies and external demands and compensate for their constraints differently. One school emphasizes a sheltering approach for Latino immigrant ELL students that creates a safe environment, emphasizes students maintaining their primary language, and prioritizes that ELL students graduate. The other school has an inclusive (non-segregated) approach that emphasizes rapid acquisition of English and holds the same expectations for ELL and non-ELL students, including meeting college entry requirements as well as graduating from high school. At each school, there are variations among teachers regarding their beliefs about students’ cultural practices and learning potential, perceptions of their own constraints and opportunities, responses to the disparity of resources and support systems for ELL students, ability to draw on students’ linguistic and cultural resources, and compliance with district mandates./nImplications are that program structures and school-level approaches for shaping ELL students’ opportunities must be examined. Additionally, further research is needed on how to organize schools that are both safe yet not segregated to create a favorable context of reception for Latino immigrant ELL students. Finally, preparation and ongoing instructional support for teachers of ELL students must help teachers develop pedagogical strategies that are effective within constrained conditions as well as foster cultural understanding, caring, and ways to build on students’ linguistic and cultural resources./nMy study contributes to research on education for immigrant ELL students and the role of teachers in shaping their educational and social opportunities.

Advisor: Warren Little, Judith
Design and Optimization of Wireless-Sensor Networks for Real-Time Monitoring in the Sierra Nevada and Sacramento-San Joaquin Delta

California relies extensively on two pieces of natural infrastructure for water storage and conveyance: the Sierra Nevada mountains and the Sacramento-San Joaquin Delta. The mountains act as a natural reservoir, storing winter precipitation throughout the year and slowly releasing it during the summer when demand is high. Snowmelt is then routed through the Sacramento-San Joaquin Delta to the state water project, which distributes water throughout California. Despite the importance of these natural environments for the state's water resources, the in-situ infrastructure for water monitoring is limited. The existing distribution of real-time snow-sensors is present only in flat, low-elevation regions, which does not adequately capture the spatial variability of snow depth in complex terrain. To address this, the state relies on monthly synoptic snow surveys, which require trained surveyors to manually measure the snow depth at locations across the Sierra Nevada. This process provides dense in-situ data but is labor intensive and temporally sparse. It also does not capture other important variables, such as soil moisture and radiative forcing, which are necessary for next-generation hydrologic modeling. In the Delta, in-situ measurements are limited to Eulerian sensors, which measure the rate of flow going past a point on shore, but are unable to resolve finer resolution flow fields, or measure properties of the water, such as temperature, turbidity, and salinity. This dissertation explores problems related to the design and optimization of wireless in-situ sensor networks for monitoring the water balance in the Sierra Nevada and flow fields in the Sacramento-San Joaquin Delta. Topics include: optimizing wireless snow-sensor placements using LIDAR data and machine learning, constructing reliable wireless mesh networks in complex terrain, estimating the spatial variability of soil moisture in montane regions from in-situ sensors, and the design and controller optimization of wireless in-situ sensors in the Sacramento-San Joaquin Delta.

Advisor: Glaser, Steven D.
Development of Chemical Probes for Studying Formaldehyde Biology

Formaldehyde (FA) is a reactive carbonyl species (RCS) produced in living systems through a diverse set of cellular pathways that span epigenetic regulation to metabolic processing of endogenous metabolites. At the same time, however, aberrant elevations in FA contribute to pathologies ranging from cancer and diabetes to heart, liver, and neurodegenerative diseases. Traditional methods for the detection of biological FA rely on sample destruction and/or extensive processing, resulting in a loss of spatiotemporal information. Disentangling the complex interplay between FA physiology and pathology motivates the development of chemical tools that can enable selective detection of this RCS in biological environments with spatial and temporal fidelity. This dissertation describes the design and applications of a FA-responsive homoallylamine trigger which undergoes imine condensation with FA, followed by 2-aza-Cope rearrangement and hydrolysis, irreversibly forming a diagnostic product. Importantly, this 2-aza-Cope reactivity-based trigger was found to discriminate FA from other RCS such as methylglyoxal, 4-hydroxynonenal, and glucosone as well as from simple carbonyl-containing species such as acetaldehyde and pyruvate./nThroughout this body of work, emphasis was placed on the design of FA probes whose responsiveness and readout could be applied to interrogate FA biology in a number of biological systems. To this end, the FA-reactive trigger was appended to a variety of useful diagnostic readouts, including intensity-based fluorescence (FA Probe-1), excitation-ratiometric fluorescence (Ratiometric FA Probe-1 and Ratiometric FA Probe-2), bioluminescence (FA Luciferin-1), and immunohistochemistry (Puromycin FA Probe-1). All of these probes were shown to be responsive and selective toward FA in vitro and subsequently characterized in various cell culture model systems. This work established the utility of the 2-aza-Cope reaction as a FA detection platform and demonstrated its versatility for generating many functional imaging probes, paving the way for future interrogation of FA biology in living, intact systems.

Advisor: Chang, Christopher J
Quantum Phenomena in Interacting Many-Body Systems: Topological Protection, Localization, and Non-Fermi Liquids

This dissertation establishes and investigates new phenomena in diverse interacting many-body quantum systems guided by three distinct, but complementary, themes: (i) symmetry and topology, (ii) localization, and (iii) non-Fermi liquids./nThe first theme concerns how the interplay of symmetry and topology can offer robust protection for a many-body system. We investigate low-dimensional quantum fermionic models from a general structural perspective. These phases can exhibit fractionalized Majorana zero-energy modes on their boundary. We devise experimentally relevant nonlocal measurements that can be used to detect these topological phases. While our primary focus is on quantum systems, topologically protected behavior can arise in classical mechanical models as well. We extend a recent connection between the topological band theory of electrons and classical physics by proposing a mechanical analogue of a topological nodal semimetal./nThe second theme concerns that of many-body localization. We demonstrate that the combination of localization, symmetry, and topology can have radical consequences for quantum systems at high energies, such as the existence of protected gapless boundary modes. We show that, even at these high energies, quantum information can be preserved, and quantum coherence recovered. Quantum coherent dynamics in this regime is unexpected and of great interest for quantum computation./nThe third direction in our study of interacting many-body systems concerns non-Fermi liquids. We construct a non-Fermi liquid by bringing together a spin-orbit coupled Fermi surface and fluctuating magnetic order. Using newly developed analytic tools for strongly coupled systems, we demonstrate the stability of the non-Fermi liquid to ordering. This identifies an experimentally accessible candidate for exploring physics that lies beyond Fermi liquid theory.

Advisor: Vishwanath, Ashvin
Social and Environmental Control of the Reproductive Axis

In order to survive and reproduce, animals must be exquisitely sensitive to their environment. Factors such as season and social setting can have powerful influence on reproductive outcomes by determining availability of mates, food, safety, or housing. Therefore, many species have evolved mechanisms to detect changes in environmental context and modify reproductive physiology accordingly. This dissertation examines the neural substrates mediating social and environmental control of reproductive physiology and behavior. The studies presented here focus on the hypothalamic neuropeptides kisspeptin and RFamide-related peptide (RFRP). These neuropeptides regulate the reproduction by modulating release of gonadotropin releasing hormone (GnRH) and downstream luteinizing hormone (LH), which in turn regulates gonadal function and sex steroid production. Chapter 2 explores the impact of aggressive encounters on kisspeptin and RFRP neuronal systems. Chapter 3 investigates how chemosensory information about a potential mate is conveyed to the reproductive axis, and how processing of this information differs across breeding and non-breeding conditions. Chapter 4 examines in detail how expression of kisspeptin and RFRP changes as males and females transition from breeding to non-breeding back to breeding condition in response to changes in photoperiod (proportion of light:dark in a 24 h day). These studies, utilizing a variety of rodent species, indicate that RFRP but not kisspeptin is sensitive to social information, whereas both neuropeptide systems integrate information about photoperiod, although in different ways. These findings inform our understanding of the complex circuitry mediating social and environmental control of physiology and behavior.

Advisor: Kriegsfeld, Lance J