VictorJuiz/thesis huggingface dataset:
Enantioselective Carbon-Carbon Bond Forming Reactions and Photochemistry Enabled by High-Valent Gold Catalysts

Enantioselective Carbon-Carbon Bond Forming Reactions and Photochemistry Enabled by High-Valent Gold Catalysts/nChapter 1 – A brief introduction to enantioselective gold catalysis is presented in this chapter. The limitations of enantioselective gold catalysis and the various methods that have been exploited to overcome these barriers in gold-catalyzed reactions are discussed. The potential of gold(III) as a solution to problems associated with enantioselective gold(I) catalysis is also proposed./nChapter 2 – The direct enantioconvergent 1,5-enyne cycloisomerization and kinetic resolution catalyzed by a gold(III) complex is described in this chapter. This represents the first highly enantioselective transformation catalyzed by a well-defined cationic gold(III) species and further corroborates our hypothesis that gold(III) can be used to induce chirality in situations where gold(I) is not successful. The transformation produces highly enantioenriched bicyclo[3.1.0]hexenes at all levels of conversion while simultaneously resulting in enantioenriched 1,5-enynes. Additionally, the nature of the direct enantioconvergent kinetic resolution is further explored along with the substrate scope of the transformation./nChapter 3 – A highly enantioselective Mukaiyama-Michael addition controlled by chiral phosphoramidite gold(III) catalysts is described in this chapter. To the best of our knowledge, this is the first report of a highly enantioselective Mukaiyama-Michael addition wherein silyl ketene acetals are suitable nucleophiles for the transformation, as well as the first report exploiting chiral phosphoramidite gold(III) catalysts as the source of chirality. The transformation was optimal with TADDOL-based phosphoramidite ligands on gold(III), resulting in high regio- and enantioselectivity. Additional studies are underway with prochiral silylketene acetals to also explore potential control of diastereoselectivity./nChapter 4 – The photophysical properties of several gold(III) complexes and their use as dual Lewis acid-photocatalysts are described in this chapter. With triplet state energies in excess of 50 kcal/mol, the gold(III) complexes have been successfully used as photosensitizers for the generation of singlet oxygen used for the oxidation of benzylic amines. Preliminary results are promising for the development of a chemoselective oxidation of amines with potential use as a late stage functionalization technique.

Advisor: Toste, F. Dean
In Search of a “Fair Explanation”: Helping Young People to Consider the Possibilities, Limitations, and Risks of Computer- and Data-Mediated Systems

Significant resources have been directed towards K-12 computing and data education over the past ten years, as part of what has come to be known as the CSforAll initiative. This initiative has focused on raising awareness of computing education among parents and students, developing situated learning progressions that resonate with many different interests and pursuits, training teachers, and addressing issues of underrepresentation in computing among females and racial minorities. In this dissertation, I argue that as the CSforAll initiative continues to expand, it is important for the education community to also reflect on the forms of knowledge that are believed to be essential, and the presumed benefits of computing and data education. Specifically, how might the goal of producing citizens with robust computing and data literacies change what is considered to be fundamental to a computing education; as well as the kinds of contexts in which computing and data science are situated?/nI use the term sociotechnical literacy to name this vision for computing education, which I define as a broad set of social and technical practices, strategies, ideas, and dispositions that can help people to reason about the computer-mediated systems that shape their everyday lives. As the term suggests, I argue that it is important for learners to engage with technical ideas as well as their social applications and implications. To examine what this might mean for teaching and learning, I describe two design experiments that I conducted with young people (ages 14 – 22). Each approach aimed to make the applications of computing primary (rather than treating applications as the backdrop from which the abstractions of computation are motivated), so that learners could examine some of the specific ways in which data and computing might be directed to particular goals, subject to real possibilities and constraints, and in relation to alternative forms of participation./nI examine the possibilities and limitations of each approach. I also analyze some of the assumptions that framed the design experiments – which were naïve, but also reflective of a broader ethos that pervades CSforAll. I reflect on what these studies collectively reveal about the possibilities, limitations, and risks of data and computing, as situated in the lives of young people; as well as what this might mean for helping young people develop a robust sociotechnical literacy. There are very real limits to what can be accomplished with computing and data alone. There are also significant benefits and risks associated with the many sociotechnical systems that shape our lives. As such, I argue that rather than positioning computing education as a remedy to various social ills, we instead offer young people a fair explanation of what computing is and is not capable of, grounded within specific contexts involving real people. I conclude with what this fair explanation might include, and how it might be fostered.

Advisor: Cheshire, Coye
Structured Tensors and the Geometry of Data

We analyze data to build a quantitative understanding of the world. Linear algebra is the foundation to algorithms, dating back one hundred years, for extracting structure from data. Modern technologies provide an abundance of multi-dimensional data, in which multiple variables or factors can be compared simultaneously. To organize and analyze such datasets we can use a tensor, the higher order analogue of a matrix. However, many theoretical and practical challenges arise in extending linear algebra to the setting of tensors./nIn the first part of this thesis, I study and develop the algebraic theory of tensors. Tensors of low real rank, as well as singular vectors and singular values of tensors, parametrize semi-algebraic sets, defined by polynomial equations and inequalities. I give exact algebraic characterizations of sets of tensors of interest, using real algebraic geometry, polyhedral geometry and computer algebra. I obtain a membership test for the set of real rank two tensors, I describe the variety of singular vectors of orthogonally decomposable tensors, and I obtain inequalities relating the singular values of the flattenings of a tensor. I show that rank and symmetric rank coincide for tensors of low symmetric rank, bounded by seven. I conclude by describing tensor hypernetworks, a flexible framework for decomposing and approximating tensors in application-specific contexts. Throughout these results, an in-depth study of small tensors is used to set up the general theory. The theoretical results explain pitfalls of existing tensor algorithms, and also suggest new approaches for finding structure in a tensor./nIn the second part of this thesis, I present three algorithms for tensor data. The algorithms use algebraic and geometric structure to give guarantees of optimality. Tensors have a close connection to multivariate distributions in statistics. I obtain the first non-trivial instance of an exact maximum likelihood estimate for a model with hidden variables. I give a numerical algorithm to recover paths from their third order signature tensors, an inverse problem from stochastic analysis. I also give an algorithm to cluster multi-dimensional data, with structured clusters encoded via algebraic constraints in a tensor. The structure facilitates the interpretation of clusters in a dataset of cancer cell lines.

Advisor: Sturmfels, Bernd
Error Estimates for Least-Squares Problems

In this thesis we consider error estimates for a family of iterative algorithms for solving the least-squares problem \min_x \|Ax-b\|_2 based on the Golub-Kahan-Lanczos bidiagonalization process. Given a lower bound on the smallest singular value of A, we show how to compute upper bounds on the Euclidean error \|x_k-x_*\|_2 as well as the backward error. In the case of the Euclidean error, we demonstrate that our bound is sharp given the information we use about the matrix A./nWe also present two new algorithms aimed at minimizing our error estimates. The first, LS-Craig, is constructed to minimize our estimate of \|x_k-x_*\|_2 with every iteration. The second, LSMB, minimizes an objective function closely related to our backward error estimate. We find that at each step the iterate x_k produced by LS-Craig is a convex combination of those produced by LSQR (which minimizes \|r_k\|_2 = \|b-Ax_k\|_2 over a Krylov subspace) and Craig's method. The iterates produced by LSMB, in turn, are a convex combination of those produced by LSQR and LSMR (which minimizes \|A\ts r_k\|_2 over the same subspace). Experiments on test cases from the University of Florida Sparse Matrix Collection show that in practice LS-Craig and LSMB perform at least as well as the existing algorithms, although never by more than a small margin. This suggests that LS-Craig could replace LSQR when stopping rules are based on the Euclidean error and LSMB could replace both LSQR and LSMR when stopping rules are based on the backward error./nFinally, we extend the definition of the backward error to the case \min_X\|AX-B\|_F where B may have any number of columns. We derive a formula for the backward error and propose two estimates that experiments suggest are highly reliable. We prove that the estimates are reliable for a few special cases, although the general problem remains open.

Advisor: Gu, Ming
Diverse Reactivity of Rhenium β-Diketiminates

Chapter 1. Previous work with group 5 imido β-diketiminates and rhenium terminal oxo complexes is summarized, which in combination provide the theoretical basis for the subsequent chapters. The overarching hypothesis and goals of this work are stated./nChapter 2. Synthetic access to the first rhenium oxo β-diketiminate is achieved. Subsequently, the oxygen atom transfer (OAT) reactivity of this complex is gauged. It is determined that OAT from this complex is limited to trialkylphosphines of a moderate steric profile (e.g. PEt3), as small trialkylphosphines (e.g. PMe3) bind strongly to the metal center, and larger phosphines (e.g. PPh3) are kinetically limited due to the encumbering β-diketiminate ligand. Nitrene transfer from the β-diketiminate ligand to the metal is also observed, implying an ancillary limitation of this ligand in low valent rhenium complexes at high temperatures./nChapter 3. Attempts to incorporate a cyclopentadienyl ligand into the rhenium oxo β-diketiminate system using NaCp led to the isolation of an olefin-supported rhenium(III) terminal oxo complex. It was found that using SnCp2 rather than NaCp leads to the intended rhenium(V) oxo Cp complex. The reactivity of this rhenium(V) complex suggested that both the Cp ligand and oxo ligand are susceptible to nucleophilic attack, yielding a variety of rhenium(III) complexes. Computational studies suggest some degree of metal-ligand conjugation (“π-loading”) exists between the Cp and oxo ligands in the starting rhenium(V) complex, which supports the observations made during reactivity studies./nChapter 4. The oxygen atom transfer reactivity of a rhenium(III) terminal oxo β-diketiminate complex is evaluated. It is shown that this compound will only transfer its oxo ligand to electrophilic reagents (e.g. isocyanides and CO) rather than nucleophilic ones (e.g. PMe3). A number of rhenium(I) isocyanide and carbonyl complexes are isolated as products of the oxygen atom transfer process. In all, the results suggest that the oxo moiety of the starting rhenium(III) complex behaves as a nucleophile, and has no demonstrable electrophilic character./nChapter 5. Reduction of a cationic rhenium(V) oxo Cp β-diketiminate with metallic sodium yields an anionic rhenium(I) complex that is both strongly reducing and basic. Accordingly, the corresponding neutral rhenium(II) and rhenium(III) hydride complexes are isolated following oxidation and protonation, respectively, of the anionic compound. Combination of the anionic rhenium(I) compound with ZnCl2 formed a tetrametallic Re(I)-Zn(I)-Zn(I)-Re(I) complex where the four metal centers are arranged in a nearly linear fashion. This compound is the first example of a Zn(I) compound to be supported exclusively by bonding to other metal centers. Computational and reactivity studies of this tetrametallic compound are also presented.

Advisor: Arnold, John
Applications and Extensions of Organization Theory: The Context of Accountable Care Organizations

Improving quality has a been a major focus of the United States healthcare system, which has led to an increase in financing schemes and care models designed to this end. Accountable care organizations (ACOs) are the among the largest of these efforts, providing incentives for providers to join together in assuming responsibility for a set of shared patients. Understanding how providers and the ACOs in which they participate achieve their quality outcomes is difficult given the complexity of the systems in which they operate. This dissertation investigates healthcare quality through several perspectives. The first paper uses a taxonomy of ACOs to explore whether the structural characteristics and prior experiences of these organizations are associated with their performance on publicly available quality and financial measures. In the second paper, practice-level characteristics including self-reported culture and ACO participation are used to explore what factors are associated with practices’ use of decision aids in the context of shared decision-making. The final paper combines the practice and ACO-level variables into a single model to compare the relative contribution of each organizational level to ACO quality.

Advisor: Shortell, Stephen M
Field Implementation of Freeway Control

This dissertation presents a series of traffic management studies including freeway and intersection traffic modeling, estimation, control methodologies and field implementation tests. First, a traffic flow prediction method that combines the most recent traffic data with historical traffic data is studied. An autoregressive moving average with exogenous input (ARMAX) model is estimated on-line based on the most recent vehicle detector station (VDS) data. Results obtained using empirical freeway mainline and on-ramp data show that this method outperforms methods that rely only on the historical average of the data to perform a prediction, especially during days with unusual traffic flow demands./nSecond, two freeway control strategies: coordinated ramp metering (CRM) and variable speed advisory (VSA) are investigated and implemented in field tests. In the control of CRM study, the freeway is modeled by the cell transmission model (CTM) and the control problem is solved by the model predictive control (MPC) scheme. The proposed CRM is deployed in a segment of California State Route 99 Northbound (SR-99N) for a five-week field test. The test results shows that the freeway efficiency can be improved by 7.25% for morning peak hours. In the VSA control study, an advisory speed limit control is designed by using traffic flow stabilization of the Lighthill-Whitham-Richards (LWR) model. The proposed VSA is deployed in a segment of California State Route 78 Eastbound (SR-78E) for a five-week field test. The test results shows that the freeway efficiency can be improved by 8.71% for morning peak hours. Both control strategies indicate freeway efficiency improvement in congested traffic./nThird, the large-scale signalized intersection traffic network control by offset optimization is also studied. The traffic network is described by a directed graph and the traffic dynamic is represented by continuous-time fluid queue model with sinusoidal arrival and departure rate assumption. The original non-convex offset optimization problem can be relaxed into a semidefinite program (SDP). The Burer-Monteiro (BM) method is used for solving the large SDP to avoid conic constraints. Two real-world traffic simulation networks, respectively in Manhattan, NY and in Pasadena, CA are constructed for demonstrating the BM method. Numerical simulation results indicate that BM method has good scalability and it can efficiently recover optimal solutions of the SDP.

Advisor: Horowitz, Roberto
QuBits, an Interactive Virtual Reality Project and Compositional Space for Sound and Image

Abstract/nQuBits, an Interactive Virtual Reality Project and Compositional Space/nfor Sound and Image/nby/nJonathan Kulpa/nDoctor of Philosophy in Music Composition/nUniversity of California, Berkeley/nProfessor Edmund Campion, Chair/nThis paper describes the QuBits project, a virtual reality (VR) environment created by the composer, offering an expanded medium for musical experience with integrated space and visuals. The QuBits VR environment is the essential supporting material for the dissertation and this paper provides a full description of the project./nThe environment was designed to explore a musical aesthetic valuing sound mass, spatial sound, evolution, and algorithmically generated sonic structures. Additionally, the user of the VR system plays a key role in shaping these musical elements. The user first must discover what behaviors are possible by exploring and through chance encounters. They can then shape each discovered behavior with nuance if they choose./nIn the VR environment, each sound has a corresponding visual component. To achieve this, a system was built with two software platforms, one for digital sound processing and another for 3D graphics and algorithmic event generation. These platforms communicate via Open Sound Control (OSC). The sounds are a mix of real world sampled sound, granular synthesis, and real-time generated synthetic sound./n/nThe QuBits VR environment represents the results of this methodology. Pros and cons of the methodology are discussed, as well as implications for future projects.

Advisor: Campion, Edmund
Characterizing and managing drivers of change in Mediterranean forest and grassland communities

Over the three chapters of my dissertation, I combined manipulative experiments and long-term monitoring data from grasslands, mixed conifer, and high elevation forests to explain emerging community shifts in California. I also applied these results to management strategies focused on global change. In the first chapter of my dissertation, I focused on the effects of shifting weather patterns on California’s annual grassland communities. The results highlighted the importance of lagged rainfall effects and two important mechanisms (dry litter and propagule production) driving grass and forb responses to lagged rainfall. For the second chapter of my dissertation, I focused on the causes and consequences white pine blister rust and bark beetles in the Sierra Nevada. Resampling long-term monitoring plots, I characterized how the invasion of white pine blister rust (Cronartium ribicola) shifted over twenty years and how recent bark beetle populations were affecting white pine health in the southern Sierra. My third chapter concludes this dissertation by critiquing resilience applications in natural resource management. By combining resilience theory with concepts from the novel ecosystem literature, management of global change can be improved.

Advisor: Battles, John J
Forms of the Peasant: Aesthetics and Social Thought in Russian Realism, 1847-1877

At the center of this dissertation’s inquiry is Russian realism’s construction of what I call “the form of the peasant.” Created by writers, this mythic image emerged in tandem with the movement’s signature formal innovations in narrative perspective, poetic voice, and descriptive style. It also gave shape to the very ideas of history, national identity, subjectivity, and language which defined Russian realism as a literary movement. The three chapters approach several major texts – Ivan Turgenev’s Zapiski okhotnika [Notes from a Hunter] (1847-1852), Lev Tolstoy’s “Utro pomeshchika” (1852-1856) and Anna Karenina (1874-1877), and Nikolai Nekrasov’s Komu na Rusi zhit’ khorosho [Who in Russia Can Live well] (1866-1877) – from a historical and formalist perspective, offering a history of realist forms in the social and intellectual context from which they emerge and to which they contribute. Close readings of narrative and poetic texts are performed alongside analyses of a range of theoretical texts that are central to Russian social thought in the mid-nineteenth century, including works by Vissarion Belinsky, Nikolai Chernyshevsky, Nikolai Dobroliubov, Alexander Potebnia, and G. W. F. Hegel. At the intersection of these analyses emerges a myth of agrarian life structured by social anxieties in three interpretative frameworks. First, realism is illuminated in its parallel development to serfdom abolition. Second, social identities (e.g., master and serf; peasant and intellectual) are shown to inhere in forms of narrative and lyric subjectivity. Finally, literature’s engagement with myths of peasant life as pre-modern or timeless belies a central preoccupation with the concept of history understood in terms of non-teleological change. Building on work across disciplines at the intersection of social thought and literary form and reassessments of realism across national traditions, this work is grounded in the belief that it is the nature of literary forms to complicate ideology, expressing ideas obliquely and exploring contradictions. My aim is to show how realism works at once to establish normative frameworks and undermine them, locating Russian realism’s engagement with the peasant myth in precisely this point of tension. Here, the “form of the peasant” expresses an escape from modernity as well as a confrontation with it. In “Forms of the Peasant,” Russian realism emerges as a literary movement with strong connections to other national traditions and historical epochs – connections based in paradigms of empire, class conflict, systems of bondage, and their aftermath.

Advisor: Flaherty, Jennifer J