VictorJuiz/thesis huggingface dataset:
Morse-Bott and Equivariant Theories Using Polyfolds

In this paper, we propose a general method of defining equivariant theories in symplectic geometry using polyfolds. The construction is twofold, one is for closed theories like equivariant Gromov-Witten theory, the other is for open theories like equivariant Floer cohomology./nWhen a compact Lie group $G$ acts on a tame strong polyfold bundle $p:W \to Z$, we construct a quotient polyfold bundle $\overline{p}:W/G \to Z/G$ if the $G$-action on $Z$ only has finite isotropy. For a general group action and if $Z$ has no boundary, then every $G$-equivariant sc-Fredholm section $s:Z\to W$ induces a $H^*(BG)$ module map $s_*: H^*_G(Z) \to H^{*-\ind s}(BG)$, which can be viewed as a generalization of the integration over the zero set $s^{-1}(0)$ when equivariant transversality holds. When $Z$ is the Gromov-Witten polyfold, $s_*$ yields a definition equivariant Gromov-Witten invariant for any symplectic manifold. We obtain a localization theorem for $s_*$ if there exist tubular neighborhoods around the fixed locus in the sense of polyfold. For open theories, we first obtain a construction for the Morse-Bott theories under minimal transversality requirement. We discuss the relations between different constructions of cochain complexes for Morse-Bott theory. We explain how homological perturbation theory is used in Morse-Bott cohomology, in particular, both our construction and the cascades construction can be interpreted in that way, In the presence of group actions, we construct cochain complexes for the equivariant theory. Expected properties like the independence of approximations of the classifying spaces and existence of action spectral sequences are proven. We carry out our construction for finite dimensional Morse-Bott cohomology using a generic metric and prove it recovers the regular cohomology. We outline the project of combining our construction with polyfold theory, which is expected to give a general construction for both Morse-Bott and equivariant Floer cohomology./nIn the last part, we show that for any asymptotically dynamically convex contact manifold $Y$, the vanishing of symplectic homology $SH(W)=0$ is a property independent of the choice of topologically simple (i.e. $c_1(W)=0$ and $\pi_{1}(Y)\to \pi_1(W)$ is injective) Liouville filling $W$. As a consequence, we answer a question of Lazarev partially: a contact manifold $Y$ admitting flexible fillings determines the integral cohomology of all the topologically simple Liouville fillings of $Y$.

Advisor: Wehrheim, Katrin
Urban greenhouse gas emissions as observed using a high-density sensor network

More than 70% of anthropogenic carbon dioxide emissions originate from cities, and that fraction is expected to grow with the increasing urbanization of the world population. Monitoring, reporting, and verification (MRV) of emission mitigation initiatives are complicated in urban areas by the combination of spatio-temporally heterogeneous landscapes of CO2 sources and poorly constrained turbulent fluid dynamics near the rough and irregular surfaces of urban topography. In this dissertation, I present a novel approach to MRV of urban emissions using a distributed network of near-surface ambient CO2 monitors stationed at 2 km intervals across an urban dome. The study area is the San Francisco Bay Area, a location characterized by a high density of disparate emission sources, irregular topography, as well as strong municipal and state level commitments to emission reductions. First, I describe the design, implementation, and evaluation of this unprecedented monitoring approach, hereafter the BErkeley Atmospheric CO2 Observation Network (BEACO2N). I demonstrate how the use of lower cost sensor technologies enables a high volume of monitors to be deployed at a cost competitive with conventional, non-spatially resolved monitoring approaches and find the lower cost monitors to be of sufficient accuracy and precision to capture typical urban CO2 phenomena. Second, I leverage this validated framework to provide the first high-resolution characterization of the neighborhood-to-neighborhood variability in local CO2 concentrations across the San Francisco Bay Area. I find significant differences even between nearby pairs of monitoring sites, leading to the derivation of a relatively short spatial correlation length scale for the study area and demonstrating a high degree of sensitivity to the unique emission sources local to each site. I determine these sensitivities to be capable of detecting changes in emission processes of policy-relevant magnitudes, providing a viable new constraint on regulations concerning, for example, fuel efficiency and vehicle electrification. Finally, I compare the CO2 concentrations measured at nine BEACO2N sites to those predicted by an ensemble of atmospheric transport models. I find large disagreements between the observations and the simulations, only a small portion of which can be explained by known measurement errors or the spread in plausible transport and emissions scenarios, highlighting the utility of high-density observations for the validation and improvement of conventional modeling frameworks. Taken together, this body of work demonstrates the promise of atmospheric observation networks based on moderate quality sensor technologies as a practicable approach to the challenge of monitoring urban greenhouse gas emission patterns and trends.

Advisor: Cohen, Ronald C
Commitment as Struggle: Teachers Serving Students in the Face of Socioeconomic Adversity

Through an in-depth, multi-case study of five schools and forty-seven teachers, I examine how teacher commitment to students plays out under conditions of socioeconomic adversity in elementary and middle schools. Relying on different sources of literature, I theorize that commitment is the degree of educators’ determination to respond to student needs. Empirically, I explore how individual teachers perceive and respond to student needs in a context where students bring more needs than educators can handle. I also analyze whether conventional factors drawn from the literature are associated with they way teachers respond to student needs./nThe findings show that teachers express their commitment as a trade-off between responsiveness and boundary-setting in the face of student needs. In the midst of this struggle, teachers are forced to draw a line between the needs that they are able to handle and the ones that they are not. Following this rationale, four types of commitment were identified: alienated, restricted, conditional, and boundless. These four types of commitment describe a spectrum of determination to respond to student needs from the lowest (alienated) to the highest (boundless). Findings also show that none of the factors theorized – expectations, self-efficacy, ethic of service, deservingness, and self-interest –distinguish teachers with stronger commitment from those with lower commitment in a straightforward manner. Rather, a set of more subtle factors differentiates more committed teachers from less committed teachers: hope, internal locus of control, a sense of meaning from transforming social disparities, valuing students as morally deserving, and meaningful integration of organizational demands with student needs./nThis study makes three contributions. It understands commitment as a phenomenon that involves behaviors and attitudes. It advances a new understanding of commitment as a trade-off between responding to student needs and boundary-setting, which softens the conventional dichotomy between committed and not-committed educators. Finally, it offers a set of novel attributes that describes higher commitment to students in the midst of the struggle to serve children in extraordinarily adverse circumstances./nImplications indicate that school leaders and policy makers should pay careful attention to teachers’ struggles to serve students who bring more needs than educators can handle. Understanding this discrepancy may lead to better strategies to soften the effects of poverty on teacher work. Also, understanding commitment as a trade-off between responsiveness and boundary-setting opens a space of influence for school leaders to gauge and support teacher work beyond the conventional dichotomy between “committed” and “not-committed” educators.

Advisor: Mintrop, Heinrich
Adapting Swarm Applications: A Systematic and Quantitative Approach

The swarm refers to the vast collection of networked sensors and actuators installed in our connected world. Many swarm applications generate, transport, distill, and process large streams of data across a wide area in real time. The increasing volume of data generated at the edge challenges the existing approaches of directly connecting devices to the cloud./nThis thesis begins with an overview of emerging swarm and the architecture design trends for swarm applications. The swarm faces challenges from the scarce and variable WAN bandwidth and the heterogeneous compute environment (from low-power microcontrollers to powerful compute units). When network resources or compute resources are insufficient, non-adaptive applications will suffer from increased latency or degraded accuracy. Existing approaches that support adaptation either require extensive developer effort to write manual policies or are limited to application-specific solutions./nThis thesis proposes a systematic and quantitative approach to build adaptive swarm applications. The solution has three stages: (1) a set of programming abstractions that allow developers to express adaptation options; (2) an automatic profiling tool that learns an accurate profile to characterize resource demands and application performance; (3) a runtime system responsive to environment changes, maximizing application performance guided by the learned profile. We evaluate our methodology with adaptations to network resources and compute resources./nFor network resources, we present a complete design and implementation of the framework AWStream and several swarm applications: pedestrian detection, augmented reality, and monitoring log analysis. Our experiments show that all applications can achieve sub-second latency with nominal accuracy drops. For compute resources, we focus on improving the profiling efficiency—using Bayesian Optimization to address the large parameter space and profile transfer to address device heterogeneity.

Advisor: Lee, Edward A.
The influence of desires on young children’s reasoning

Previously developmental psychologists have explored how young children reason about/ndesires, and how desires constrain children’s inferences. For example, early research on theory of/nmind explored when young children come to understand that people have different desires, and/nhow young children reason about conflicting desires across individuals or over the course of time/n(e.g. Wellman and Liu, 2004). Relatedly, studies have explored how desires influence children’s/ninferences about actions, finding that young children generally believe that people act/nconsistently with their desires (e.g. Kushnir, Gopnik, Chernyak, Seiver, and Wellman, 2015)./nStudies on wishful thinking and optimism, on the other hand, have found that desires may more/nbroadly constrain inferences across a variety of domains. In particular, studies have shown that/ndesires bias older children’s and adults’ predictions about stochastic events (e.g. Krizan and/nWindschitl, 2009). In Chapter 1 I outline previous research exploring how young children reason/nabout desires./nIn Chapters 2 through 4 I present a series of cross-cultural developmental studies/nexploring how desires impact children’s inferences. In Chapter 2, I explore the development of/nbeliefs about agency in Chinese and U.S. 4- and 6-year-old children, and if children believe that/npeople can ‘choose to’ act inconsistently with a desire, or practice self-control. Findings suggest/nboth differences and similarities across groups of children./nIn Chapter 3, I present a similar study contrasting Peruvian and U.S. 4- to 7-year-olds. I/nalso explore if developmental changes in beliefs about self-control are related to first person/nexperiences practicing self-control. When contrasting Peruvian and U.S. children, findings/nsuggest differences in beliefs about self-control, however children demonstrated comparable/nself-control skills. In addition, cultural group mediated the relationship between children’s 1st/nperson experiences practicing self-control, and their corresponding beliefs about self-control./nIn Chapter 4, I present a series of studies exploring the influence of desires on young/nPeruvian and U.S. children’s (3-to 7-year-olds) predictions about stochastic events. Findings/nsuggest that desires strongly constrain young children’s inferences across cultures./nFinally, in Chapter 5 I discuss the implications of these findings, as well as present/nseveral avenues for future research. These findings more broadly contribute to our scientific/nunderstanding of how young children reason about desirable possibilities, and how culture/nimpacts conceptual development.

Advisor: Gopnik, Alison
Nonlinear optical properties and spectroscopy of Weyl semimetals

Nonlinear optical properties of materials are useful both for their practical applications, but also as a characterization tool for symmetry in novel systems. However, the nonlinear optical response of a material is often not as one of its fundamental properties, along with band structure, linear conductivity, etc. This has particularly been the case with the recent interest in “quantum materials”: materials such as high-Tc superconductors, topological materials, and exotic magnets. Weyl semimetals are a class of materials where band-touching points have divergent Berry curvature, and are host to a number of unique physical phenomena such as the chiral anomaly and Fermi arc surface states. From the nonlinear optics perspective, Weyl semimetals are interesting since inversion-symmetry breaking Weyl semimetals have been experimentally realized, and breaking of inversion-symmetry is crucial for second order nonlinear optical phenomena./nIn this dissertation, I present results from a number of studies of the Weyl semimetal TaAs and related compounds using nonlinear optical techniques. As detailed here, TaAs was discovered to have the largest measured nonlinear optical susceptibility of any material, and further, this susceptibility was found to be caused by a resonance in the spectrum of nonlinear optical conductivity. TaAs was also measured to have a photogalvanic effect that has qualitatively different characteristics depending on the direction of measurement. These nonlinear optical properties of the TaAs family of materials may lead to interesting applications in near-field nonlinear optics, and optical pulse shaping below the diffraction limit.

Advisor: Orenstein, Joseph W
Asymptotically Conical Metrics and Expanding Ricci Solitons

In this thesis we first show, at the level of formal expansions, that/nany compact manifold can be the sphere at infinity of an asymptot-/nically conical gradient expanding Ricci soliton. We then prove the/nexistence of a smooth blowdown limit for any Ricci-DeTurck flow on/nR n , starting from possibly non-smooth data which is asymptotically/nconical and sufficiently L ∞ -close to an expanding soliton on R n . Fur-/nthermore, this blowdown flow is an expanding Ricci-DeTurck soliton/ncoming out of the asymptotic cone of the initial data.

Advisor: Lott, John
The Development of Transition Metal-Catalyzed Fluoroalkylation and Fluoroenolate Arylation Reactions

The following dissertation discusses the development and mechanistic study of reactions that form bonds between fluorine-containing substituents and functionalized aromatic compounds. In particular, this work focuses on transition metal-catalyzed reactions that form aryldifluoromethylcarboxylic acid derivatives and trifluoromethylarenes./nChapter 1 discusses the properties and applications of fluorine-containing organic compounds and provides an overview of methods for the synthesis of fluoroalkylarenes. The challenges associated with developing transition metal-catalyzed reactions that form aryldifluoromethyl carboxylic acid derivatives and trifluoromethylarenes are also described, and strategies to address these challenges are discussed./nChapter 2 describes the development of a copper-catalyzed cross-coupling reaction to form aryldifluoroamides from a-silyldifluoroamides and aryl iodides, vinyl iodides, or heteroaryl bromides. The reactions tolerate a variety of functional groups, and the aryldifluoroamide products can be converted to a diverse array of difluoroalkylarenes. The application of this reaction to the synthesis of fluorinated compounds of potential biological interest is also described./nChapter 3 describes the synthesis, characterization, and reactivity of fluoroenolate complexes of palladium. A systematic study of reductive elimination from fluorinated ester, amide, and nitrile enolate complexes was conducted, and factors influencing the rate of reductive elimination were determined./nChapter 4 discusses the development of a cross-coupling reaction to form aryldifluoronitriles. In the presence of copper, an a-silyldifluoroacetronitrile reagent couples with aryl halides in moderate to high yields./nChapter 5 describes the investigation of reductive elimination to form an aryl- trifluoromethyl bond by treatment of arylnickel(II) trifluoromethyl complexes with single-electron oxidants. The reactions occur at room temperature in up to 70% yield./nChapter 6 discusses the identification of new classes of ligands that promote reductive elimination to form trifluoromethylarenes from arylpalladium(II) trifluoromethyl complexes. The reductive elimination reactions occur under mild conditions and at moderate temperatures.

Advisor: Hartwig, John F
Essays on Consumption and Labor Supply

This thesis investigates topics in consumption and labor supply using "big" data from bank accounts and credit cards from personal financial records. Chapter 1 discusses how these data allow researchers to examine economic activity in gig economy jobs, a sector has been difficult to measure due to lack of data. Chapter 2 focuses on one popular gig economy industry, ridesharing, to explore whether flexible work can help workers better smooth their consumption. Chapter 3 examines how these data can be used to measure the marginal propensity to consume out of permanent shocks by exploiting changes in gasoline prices.

Advisor: Card, David
Romer, David
Fluorogenic and Covalently Targeted Voltage Sensitive Dyes

Fluorescent reporters of membrane potential are important tools in neuroscience, offering a non-invasive, real-time optical readout of neuronal activity. Voltage sensitive dyes of the VoltageFluor family report neuronal activity with high sensitivity and sub-millisecond response times, but lack the cell-type specific targetability of genetically encoded tools, placing certain constraints on their applicability in complex environments (i.e. tissue slice, in vivo, sub-cellular localization)./nThe work presented in this thesis addresses these problems through two distinct strategies. In Chapters 1 and 2 I describe the development of weakly-fluorescent, photoactivatable “caged” VoltageFluors. Spatial control of illumination allows for release of VoltageFluor at the single cell and subcellular levels in cultured mammalian neurons, and subsequent recording of evoked action potentials. This caging strategy has proven to be generalizable, and Chapter 3 and Appendix 1 detail the synthesis of enzymatically-activatable probes. In Chapter 4 I present a strategy for the selective labeling of cells with a VoltageFluor derivative, which harnesses the known covalent interaction between a short peptide, SpyTag, and its cognate binding protein, SpyCatcher. I synthesized a series of VoltageFluor-SpyTag conjugates, or VoltageSpy dyes, which specifically label the outer membranes of cells expressing SpyCatcher at the cell surface, with minimal off-target labeling, and without requiring a wash step. I demonstrate the application of this system to imaging spontaneous activity in cultured mammalian neurons, as well as imaging evoked activity in axons and dendrites. Appendix 2 describes efforts to apply VoltageSpy dyes in mouse brain slice. Finally, Chapter 5 presents a general strategy for minimizing phototoxic effects sometimes encountered when imaging with VoltageFluor dyes, using either bath applied triplet state quenchers or an intramolecularly-stabilized VoltageFluor derivative. Cyclooctatetraene was found to be an effective protective agent – a result which may prove broadly useful in imaging VoltageFluor dyes, improving the applicability of the fluorogenic and covalently-targeted tools presented in Chapters 1-4.

Advisor: Miller, Evan W
E-contact: Creating Friendships Between Adolescents from Different Backgrounds to Increase Positive Outgroup Feelings

In this study, the effects of adolescent intergroup friendship development on positive outgroup feelings (POF) are examined through an E-contact collaboration in drama classrooms between a Majority-White high-income (WHI) school and a Majority-Minority low-income (MLI) school. Forty-eight students participated in the study, six from the MLI school and 42 from the WHI school. A single cohort longitudinal approach was employed across two time-intervals and a 2 (Intervention Condition: control or experimental, between participants) by 2 (School: School 1 or School 2, between participants) by 2 (Data collection time: Time 1, Time 2, within participants) pre-post-control design. Students from the WHI and MLI high schools were split into control and experimental groups and friendship was enhanced in the experimental group./nThe first hypothesis was that participants who were in the experimental E-contact condition would experience more feelings of friendship with their partner, thus also report more POF than those in the control condition. The results indicated that group assignment did not have a significant effect on the relationship between POF at Time 1 and POF at Time 2. However, Time—independent of group assignment—was significantly associated with change in mean POF (p = 0.0038). The second hypothesis was that the four known mediators—anxiety, knowledge about the outgroup, empathy and perspective taking, and inclusion of other in self (IOS)—would have an impact on the relationship between friendship at Time 2 and POF at Time 2. The only mediator found to have an impact on the relationship between friendship at Time 2 and POF at Time 2 was IOS. Results and future directions are discussed.

Advisor: Worrell, Frank C
Combinatorial Topology and Applications to Quantum Field Theory

Topology has become increasingly important in the study of many-body quantum mechanics, in both high energy and condensed matter applications. While the importance of smooth topology has long been appreciated in this context, especially with the rise of index theory, torsion phenomena and discrete group symmetries are relatively new directions. In this thesis, I collect some mathematical results and conjectures that I have encountered in the exploration of these new topics. I also give an introduction to some quantum field theory topics I hope will be accessible to topologists.

Advisor: Shende, Vivek