VictorJuiz/thesis huggingface dataset:
Imaging Individual Chemical Bonds and Tuning Single-Molecule Charge States at Surfaces

In an effort to make advances in electronics through ever smaller devices, the field of molecular electronics has emerged as a natural step in achieving ultimate miniaturization of devices down to the size of single molecules. Progress in molecular electronics is intimately linked to understanding these devices at the atomic and molecular length scales at which they operate. As a move in this direction we have performed local probe studies in which we have nondestructively imaged the products of chemical reactions within molecular electronics elements. We have also imaged and tuned the orbitals and charge states of individual molecular electronics elements on surfaces. This dissertation, after introducing the field of nanoelectronics and the local probe techniques used in the study, reports on imaging of chemical structures of on-surface synthesized molecules and conductive polymers with individual-chemical-bond resolution and their relationship to the electronic structure. Depending on the specific molecules and surfaces used, the on-surface synthesized molecular structures formed single molecule products (monomers), chemically reacted intermediates, or conductive polymers exhibiting extended electronic structure along their backbone. This dissertation additionally demonstrates orbital gating of molecules on a back-gated graphene device. The energy alignment of molecular orbitals on graphene was tuned using an electrostatic back-gate, which resulted in molecules switching between neutral and negatively charged states. This control of charge states of single molecules on surfaces and identification of on-surface synthesized reaction products with sub-molecular resolution contributes to our understanding of molecular electronics elements at their natural length scales.

Advisor: Crommie, Michael F
Disappeared Subjects: Girls of Color, School Discipline and Punishment

The purpose of this study was to examine the effects of school discipline policies and practices on girls of color. This qualitative study used case study method, interviews, participant observation and document analysis to explore the multiple levels of discipline at a high school located in northern California. Twenty girls of color with discipline records were interviewed about their experiences with school discipline. Fourteen adults including teachers, counselors and administrators were also interviewed about their interpretations of students' experiences. To comprehend the girls' experiences, the study was guided by the following questions: (1a) What is the discipline environment including the federal, state and district policies that shape the case study school policies? (1b) According to school personnel, how are these policies implemented and what are their perspectives on these policies? (2) What experiences did girls of color have with discipline policies and practices at the case study site? (3) What did the girls of color identify as the factors that contributed to their discipline records at school?/nFindings demonstrate that school discipline environment is a multileveled punitive structure. School discipline policies are forms of racialized and gendered disciplinary power that attempt to normalize students according to dominant standards. Students who fail to meet racial and gender norms are subject to multiple forms of punishment including referrals, suspensions and arrests. Findings also demonstrate that girls of color are subject to both formal and informal forms of punishment. Black girls, in particular, are also subject to informal punitive practices. The girls' narratives suggest that their experiences with school discipline include racial profiling and gratuitous punishment. Additionally, findings indicate that most of the girls of color who have been disciplined at school have also experienced intersecting forms of violence outside of school. Findings suggest that the girls' experiences with violence outside of school affect their behaviors in school. Results also indicate that discipline policies punish girls for how they respond to the conditions that shape their lives./nInformed by Critical Race Feminism and Black feminist theory, this study analyzes the girls' disciplinary experiences within structural and institutional contexts. The theoretical and methodological approaches employed in this study provide an intersectional approach to examining school discipline policies and punitive practices. Findings contribute to studies concerning the intersections between race, gender, school discipline and punishment.

Advisor: Nasir, Na'ilah
Using Multiple Representations to Resolve Conflict in Student Conceptual Understanding of Chemistry

Much like a practiced linguist, expert chemists utilize the power and elegance of chemical symbols to understand what is happening at the atomic level and to manipulate atoms and molecules to effect an observable change at the macroscopic level. Unfortunately, beginning chemistry is often taught in a way that emphasizes memorizing the symbolic representations of equations and reactions without much opportunity to meaningfully connect the observable macroscopic phenomena with an understanding of the chemistry taking place at the atomic level. The compartmentalized manner of chemistry instruction in most chemistry classrooms further nullifies the efficacy of the triplet relationship to connect between macroscopic observations, symbolic representations, and atomic scale views. If symbolic representations are presented as the goal of instruction, rather than as the means to gain understanding, then students will be impaired in developing a coherent understanding of chemical principles./nThis dissertation describes the development and implementation of an interview study to examine how undergraduate students interpreted multiple representations of a chemical equilibrium. To establish a baseline of ideas, students first were coached to verbally generate successive representations. They were then cued to think about the chemistry occurring between atoms and ions at the molecular level. Next, an experiment involving a change in states of matter and color was performed which paralleled the symbolic representations. Through self-explanations and verbalizing of conjectures, students were encouraged to explore, interpret, and refine their understanding of the observations related to the chemical symbols presented to them. Finally, with the goal of fostering a deeper understanding of the process of equilibrium, a dynamic visualization of the molecular level was introduced as a tool for helping students connect these multiple representations./nThis study revealed that one way in which students develop conceptual understanding and resolve conflicts between different representations of the same phenomena is by verbalizing their ideas as a conjecture (as a verbal explanation to advance towards a hypothesis). Thus, it is proposed that symbolic representations are most effective viewed not as an end goal but as a bridge for connecting macroscopic, visible phenomena with what is occurring at the molecular, invisible level. When the focus on merely memorizing chemical equations and symbols is removed, students can gain a coherent understanding of the meaning available when multiple representations are viewed together.

Advisor: Stacy, Angelica M
Shaking Table Evaluation of Reinforced Concrete Bridge Columns Repaired using Fiber Reinforced Polymer Jackets

After an earthquake event it is the responsibility of the engineers to decide if the bridge structure is safe for the traffic flow, requires repair or needs to be replaced completely depending on the damage level. Effective, economical and timely repair of Reinforced Concrete (RC) bridges after a seismic event is crucial to avoid traffic congestion and lengthy detours. Fiber Reinforced Polymer (FRP) composite laminates are one of few options with several advantages. Use of FRP jackets in structural engineering is gaining interest in applications such as strengthening weak structural elements, improving the existing structure capacity to resist increased loads due to change in use of structure and retrofitting structural elements for seismic upgrades. The study presents shaking table experimental investigation to evaluate the use of FRP for repairing RC bridge columns with circular cross-sections./nTwo ¼-scale RC columns were tested in as-built configuration. Both tests had identical geometry and reinforcement details except for the spacing of the transverse reinforcing bars. One column had closely spaced hoops satisfying code requirements and the other had larger spacing, representing a shear-critical column. The test specimens were subjected to a series of horizontal and vertical excitations on a shaking table and experienced moderate to high damage. The damaged columns were subsequently repaired with unidirectional FRP composite laminates and subjected to the same set of earthquake excitations. The obtained experimental data showed that the repaired columns achieved higher strength and ductility with lower residual displacements compared to the as-built ones contributing to the resiliency of the bridge system./nA three-dimensional (3D) Finite Element (FE) model was developed and calibrated using the experimental test results. A bilinear confined concrete model was adopted to model the constitutive relationship of the FRP confined concrete without explicitly modeling the FRP composite jacket. Due to variability of the material properties, several calibration parameters were studied to develop a reliable FE model. The results of the dynamic FE analysis showed great potential for 3D modeling of the repaired test specimens. From this study, it is concluded that the used FRP composite laminates represent a viable solution for the effective and rapid repair of damaged RC bridge columns. A parametric study was conducted to evaluate the horizontal force, deformation, and confining strain response of the retrofitted RC bridge columns using the computational model. The response of the FE models with different number of FRP plies in the jacket was investigated. The analytical results suggested that increasing the number of FRP plies in the jacket significantly changed the confining strains response of the confined cross-section but the global force-deformation was not significantly affected.

Advisor: Mosalam, Khalid M
Classification, Follow-Up, and Analysis of Gamma-Ray Bursts and their Early-Time Near-Infrared/Optical Afterglows

In the study of astronomical transients, deriving knowledge from discovery is a multifaceted process that includes real-time classification to identify new events of interest, deep, multi-wavelength follow-up of individual events, and the global analysis of multi-event catalogs. Here we present a body of work encompassing each of these steps as applied to the study of gamma-ray bursts (GRBs). First, we present our work on utilizing machine-learning algorithms on early-time metrics from the Swift satellite to inform the resource allocation of follow-up telescopes in order to optimize time spent on high-redshift GRB candidates. Next, we show broadband observations and analysis of the early-time afterglow of GRB 120119A, utilizing data obtained with a dozen telescope facilities both in space and on the ground. This event exhibits extreme red-to-blue color change in the first few minutes after the trigger at levels unseen in prior afterglows, and our model fits of this phenomenon reveal the best support yet for the direct detection of dust destruction in the local environment of a GRB. Finally, we present results from the PAIRITEL early-time near-infrared (NIR) afterglow catalog. The 1.3 meter PAIRITEL has autonomously observed 14 GRBs in under 3 minutes after the burst, yielding a homogenous sample of early-time JHK light curves. Our analysis of these events provides constraints on the early-time NIR GRB afterglow luminosity function and gives insight into the importance of dust extinction in the suppression of some optical afterglows.

Advisor: Bloom, Joshua S.
Regulation of crossover recombination in Caenorhabditis elegans

Most eukaryotes reproduce sexually, which requires the creation of gametes through a specialized cell division known as meiosis. Crossover recombination is an essential feature of meiosis: in individuals, it facilitates proper chromosome segregation to prevent the formation of aneuploid embryos; within populations of species, it generates novel combination of alleles, to promote genetic diversity and remove deleterious mutations. Crossovers are initiated by programmed double-strand breaks (DSBs), which are a highly toxic form of DNA damage. Meiosis requires a cell to maintain an equilibrium between forming enough DSBs to generate an adequate number of crossovers, but not so many DSBs that some are left unrepaired. Therefore, recombination is subject to strict regulation at all levels, from DSB formation to crossover resolution via a certain mode of DSB repair. In this dissertation, I investigate crossover resolution pathways in the model nematode C. elegans. To ensure the repair of all DSBs formed during meiosis, some organisms have multiple, compensatory repair pathways. Recent studies in C. elegans have identified two parallel pathways with partially overlapping resolvases, XPF-1 and MUS-81. Although XPF-1 and MUS-81 act interchangeably to resolve crossovers in wild-type animals, I show that each becomes required under conditions that threaten chromosome integrity, whether from exposure ionizing radiation or reducing the concentration of condensin, a complex required for proper chromosome structure. Conditions that independently do not create a requirement for a particular resolvase can, when combined, generate a requirement, indicating that these pathways are influenced by factors that act in a combinatorial manner. Although resolvase dependence in irradiated and condensin-depleted animals correlates with the extent of DNA damage, I demonstrate that the absolute number of DSBs is not solely responsible for invoking a requirement. Thus, DSB repair pathway choice may generate different classes of crossover depending on the DSB provenance or cellular reactions to the inducing condition. This work provides insights into the complexity of DSB repair pathways and establishes a framework for the future of pathway interactions, especially under circumstances that stress ordinary repair processes.

Advisor: Meyer, Barbara J
Editing the Socialist Canon: Forming Identity through Censorship in Poland and the GDR under Stalin

My project, "Editing the Socialist Canon: Forming Identity through Censorship in Poland and the GDR under Stalin" considers censorship as a kind of canon formation by exclusion that weeded out the unacceptable works rather than promoting the desirable. By attempting universal control of printed material, the censors implied that anything published was not only acceptable, but in some manner actually Socialist. After the Second World War, literary culture was not a secondary matter to be monitored in case it might become a refuge of sedition. Rather, it was constitutive of the new Socialist state identities that the parties were attempting to form. Within this framework, I consider the Polish and East German cases, which sat at opposite ends of the spectrum of both severity and acknowledgement of censorship. My study aims to determine the extent of and limits on variation that the system allowed between states, as well as deeper patterns of negotiation within them. While the constant pressure of the Soviet Union certainly imposed some uniformity on these constructions, each state worked within the context of its own tradition and responded to its own insecurities. Critically, though, whatever its aspirations, the system was never homogenous. Individual censors perceived matters of tradition and threat differently, and indeed, brought their own understandings and misunderstandings of Marxist orthodoxy to their work, creating a result that was far more chaotic than an outside view would suggest. To illustrate these wider themes, I will discuss the publication of classic and contemporary novels from both inside and outside Poland and the GDR. In the negotiations between orthodox and popular literature, it becomes possible to understand something of the line between didactic theory and practical exigency as they began to shape each other. The first half of my dissertation considers the meaning and effect of the actual structure of the offices, with chapters devoted to their institutional functioning, to the intellectual formation of the elites who created them, and to the training and supervision of the everyday censors. The second half looks into the margins of the censor's work, where the limits of the permissible and of the censor's power met. It considers the categories of genre, traditional literature, books from foreign countries, and those by contemporary authors at home.

Advisor: Connelly, John
CdSe/CdS Tetrapod Quantum Dots as Stress Probes: Characterization, Development, and Applications to Polymer Science and Biophysics

The bulk properties of materials and biological systems depend on their microscale behavior. This is intuitive to chemists who are used to thinking of molecular constituents dictating chemical properties at the macroscale. This bottom-up understanding of materials can be extended to mechanical properties, such as Young's modulus, catastrophic failure modes, which can begin as nanoscale void formation, and polymer chain deformations that occur during mechanical loading. Such fundamental mechanical properties are also crucial in biology, where the viability of an organism is dependent on cell function and behavior. For example, tumorigenesis and metastasis of cancer depends on the ability of a cancerous cell to generate traction forces and move through the body./nThis dissertation details recent developments on the tetrapod quantum dot (tQD) as a fluorescence stress probe. The nanometer size and optical properties of the tQD make it uniquely suitable for studying forces and mechanisms of mechanical deformation at the smallest length scales. First, background is provided on colloidal semiconductor quantum dots in general and the tetrapod in particular. Second, development and application of the tQD in synthetic polymer materials is discussed. Third, applications of the tQD as a sensor for cellular biophysics are demonstrated. Finally, further characterization of single tQD properties and future studies are discussed and proposed.

Advisor: Alivisatos, Armand P.
Ivory Tower of Babel: Tartu University and the Languages of Two Empires, a Nation-State, and the Soviet Union

This is the history of a remarkable multilingual university and university town on the edge of Europe under four different states: the Swedish Empire (1632-1710), Russian Empire (1802-1917), National Republic of Estonia (1919-1940), and Soviet Union (1944-1991). In every incarnation Tartu University was founded in the throes of a war that reconfigured political boundaries, intellectual ideals, and languages of Europe: the Thirty Years War, the Napoleonic Wars, World War One, and World War Two. Tartu's ever changing political and linguistic identity makes the University that once held the most powerful telescope in the world a good observatory upon the history of Europe and Russia as well as the globe and the cosmos. But ultimately, this is as much a tale of continuity as transformation./nAt a skeptical distance from all the metropolitan capitals that founded and funded it (Stockholm, Saint Petersburg, Tallinn, Moscow), Tartu stood for an ideal of Europe that was at once more universal and more particular than that of any state that laid claim to its academic culture. In fact, its actual role approximated the Biblical myth of the Tower of Babel: intended each time to help build a new state in a new language (both literal and ideological), Tartu University ended up cultivating other languages for remembering the past, understanding the present, and imagining the future. This was especially true of the Soviet period--the focal point of my dissertation--when Tartu taught Bolshevik ideology in two official languages (Estonian and Russian), but became known throughout the Soviet Union as an "oasis of Europe" with numerous communities of linguistic and cultural study that seemed to stand apart from the state, but from each other as well, each in the bubble of its own literal and academic language./nThe most famous of these communities was the "Tartu School of Semiotics" led by the Professor of Russian Literature, Yuri Lotman. By situating Tartu University's most famous scholar of the twentieth century against the background of his everyday life among Estonian-speaking strangers rather than his scholarly ties with Russian-speaking friends, I want to show what Lotman's theory of culture--especially the binary divide between Europe and Russia at its core--owes to Tartu. Lotman's idea that universal knowledge cannot be found in any one universal language, but must be sought in translation between particular ones, is thus both my method and my argument. Juxtaposing numerous perspectives composed in multiple languages, I show how Tartu University's uncomfortable position in space and time between languages and states (rather than firmly embedded in any one) allowed its scholars to see the world in terms (and languages) well beyond those imagined by any official ideology or discourse. Thus, Tartu became for them--as it can be for us--an excellent observatory on the relationship between the particular and the universal, the national and the cosmopolitan, and Russia and Europe.

Advisor: Slezkine, Yuri
Anderson, Margaret L