VictorJuiz/thesis huggingface dataset:
Refining the mathematics knowledge base [electronic resource] : the relationship between knowledge, practice, and student learning
Keywords: Education.

Understanding the knowledge that teachers must bring to their classrooms is critical to the advancement of the field of teacher education. Understanding how teacher knowledge impacts various aspects of teacher practice is also critical. Understanding the interplay between teacher knowledge and practice, and consequently the result that this relationship has on student learning is most important. This dissertation attempts to advance our collective understanding of the complex relationship between teacher knowledge, teacher practice, and student learning in the field of elementary mathematics. Four third-grade teachers were followed as they taught a subset of lessons in a unit on fractions. The study first investigates the types of knowledge that the teachers brought to their classrooms. Then, an examination is conducted of the way in which these types of knowledge impacted their teaching practice. Finally, the student learning that resulted over the course of these lessons is discussed. This study supports the widespread belief that teacher knowledge is important to instruction. The descriptions of the case study teachers highlight that their varying levels of knowledge resulted in unique aspects of practice being emphasized in their classrooms. This dissertation documents the differences in teaching practice and the trade-offs that produce differences in student learning. Interesting student learning patterns emerged, based on qualitative student interviews. Medium students from classrooms in which teachers focused for more sustained periods on mathematical concepts seemed to demonstrate greater procedural fluency and deeper conceptual understanding than their peers in the other classrooms. Low students in classrooms where fluency was the focus seemed to show slightly greater procedural fluency, though less conceptual understanding, than their peers in the classrooms that spent more time on concepts. High students showed no appreciable difference across all classrooms. This study adds to the field by introducing a new construct, the conceptual threshold, to offer an explanation of these student learning trends.
Regulable and cell-type-specific rescue of Niemann-pick disease type C, a neurodegenerative lysosomal storage disorder [electronic resource]
Keywords: Developmental Biology.

Niemann-Pick disease type C (NPC) is a rare metabolic lysosomal storage disorder (LSD) marked by accumulation of large quantities of cholesterol, lipids and other metabolites in cells. Though the disorder has been extensively explored using various genetic animal models, an understanding of the molecular and cellular pathology of the disease remains limited. A cell-type-specific and regulable rescue mouse model of NPC disease was engineered in order to identify the therapeutically relevant cell type and ascertain the effect of inflammation on disease progression. With the current information presented in this dissertation, a probable road map of NPC disease pathology has been drawn. The road map for NPC may also be applicable to, or act as a template for, other lysosomal storage diseases and neurodegenerative disorders with similar pathologies.
Regulatory response to environmental challenge in caulobacter crescentus [electronic resource]
Keywords: Developmental Biology.

Bacteria have evolved robust systems to sense environmental stimuli and limit proliferation under unfavorable conditions. While bacterial defense mechanisms have been characterized, the integration of environmental signals into the regulation of growth and development remains for the most part a mystery. The goal of this work was to identify the mechanisms by which the aquatic bacterium C. crescentus integrates information from the environment into the regulation of growth and development. I studied the transcript and protein changes that occur in C. crescentus in response to nutritional deprivation. The integration of high-throughput transcriptome and proteome analyses allowed me to obtain a comprehensive view of the process. The transcriptome changes were the starting point for the identification of genetic regulatory pathways involved in the response to environmental challenge. The alternative sigma factor SigT, one of the key regulators identified, was shown to activate the expression of a core set of general starvation-stress response genes that are cell cycle regulated during normal development in C. crescentus, and are candidates to mediate the inhibition of growth and division occurring upon environmental challenge. Furthermore, the SigT pathway was shown to directly integrate information from the environment into the circuit that regulates cell cycle progression, through the post-transcriptional regulation of the CtrA master regulator. The molecular analyses were complemented with cell biology studies, which revealed the differential effects of starvation and osmotic stress on chromosome replication and polar morphogenesis in swarmer cells. Overall, this work contributes to the emerging understanding of how the well-characterized regulatory circuit that controls cell cycle progression in C. crescentus integrates environmental signals.
Religion and nation [electronic resource] : identity manipulation in diverse societies
Keywords: Political Science

This research examines the ways in which national and religious identities condition cooperation in a diverse society, thus ameliorating or exacerbating the challenges posed by diversity for economic development. It asks whether national and Islamic identities in Indonesia---promoted by the main ideological camps in the country---can affect the ease of cooperation across ethnic and religious lines in a large and diverse population. The research employed a novel methodological approach that combined behavioral economic experiments with randomized psychological priming for identity. The results show the efficacy of both national and Islamic identities in conditioning inter-ethnic and inter-religious generosity. The study explores the political contexts of the results in Indonesia and the specific motivations behind patterns of behavior exposed in the lab. It demonstrates both the malleability of identity to political manipulation and the limits of this manipulation set by the power and status relations in society.
Resistance switching mechanism in TiO2 [electronic resource]
Keywords: Materials Science and Engineering

Resistive Random Access Memory (ReRAM) has attracted significant attention recently, as it is now considered as the promising candidate for the next generation of non-volatile memory device, due to its high density, low operating power, fast switching speed, and compatibility with conventional CMOS process. Among many resistance switching materials, TiO2 has been widely studied. However, the most challenging issue is that the underlying switching mechanism is lacking in-depth understanding. It has been proposed that the resistance switching is strongly coupled with the presence and a preferential distribution of oxygen vacancies involving the formation of a conductive filament. Although many experiments have been done to address the switching mechanism during the last decade, it is hard to figure out what happens at microscopic level. Therefore, systematic interpretation about the microscopic details of the role of oxygen vacancies in the formation of a conductive filament is essential. To address the conduction and the resistance switching mechanism, the effect of oxygen vacancies on the electronic structures in TiO2 has been investigated using first principles calculations based on density functional theory. In this dissertation, we report "ON"-state (Low Resistance State) conduction mechanism of rutile TiO2 including oxygen vacancies, and then the transition from "ON" to "OFF"-state (High Resistance State) is investigated. Although it is known that TiO2 exhibits n-type semiconducting property with extra electrons generated by the formation of oxygen vacancies, "ON" and "OFF"-state conductivity during resistance switching cannot be explained by isolated single oxygen vacancy. We calculated electronic characteristics such as density of states, electron localization function, band decomposed charge density distribution, and energy band structure, and show the influence of oxygen vacancy configurations on these properties and on the resistance change. Oxygen vacancy ordering and diffusion of either oxygen vacancy or hydrogen impurities have a significant impact on both the formation of the conductive filament and the transition from "ON" to "OFF"-state. Results from this study indicate that the "ON"-state conduction and resistance switching model that can be ascribed to the formation and rupture of conductive filament consisting of oxygen vacancy-ordered structure.
Re-writing the myth [electronic resource] : Gershom Scholem, zionism, and kabbalah
Keywords: German Studies.

The objective of this dissertation is to offer a fundamental reevaluation of Gershom Scholem, his life and his work until the year of the publication of Major Trends in Jewish Mysticism, 1941. The following chapters describe, on the one hand, the twists and turns of Scholem's life from his youth in Berlin before the First World War and until becoming a fulfilled historian, working in the Hebrew University in Jerusalem during the Second World War. And they discuss Scholem's grand thesis of Jewish modernity as described in Major Trends, starting with the Spanish expulsion in 1492, leading to the creation of the Lurianic myth of exile, through the traumatic eruption of Sabbatian heresy that ended with the splintering of the Jewish national spirit on the doorstep of a new era in Jewish history. The dissertation shows how Scholem's historical thesis about the development of Jewish history was fundamentally shaped by the concerns, ideas and events that were instrumental to Scholem in his life. Living in exile in Germany aspiring to overcome social alienation and the experienced mechanization of mass society translated in Scholem's mind to a vision of Zionism and in turn to an idea about the revival of the ancient myth of the Jewish people. The dissertation thus sets out to prove that not only that Scholem self fashioning was extremely sided, but also the relation between his political views and his work on the Kabbalah were dramatically more complex than otherwise assumed.
Rhodium-catalyzed oxidation reactions for the synthesis of diamines and polyamines [electronic resource]
Keywords: Chemistry

The utility of 1,2- and 1,3-diamines is far-reaching as the diamino structural motif is found in pharmaceuticals, ligands used for asymmetric catalysis, and natural products. While chemists have developed a number of effective methods for installing oxygen-containing functional groups, the synthesis of equivalent nitrogenous structures remains an enormous challenge. For example, the catalytic dihydroxylation of olefins is a transformation covered in every undergraduate organic chemistry textbook, and the development of its asymmetric variant has garnered a Nobel Prize. Yet, despite extensive effort, the analogous diamination reaction has eluded synthetic chemists for more than 40 years. Densely-functionalized nitrogen-containing molecules, such as the naturally-occurring antibiotic pactamycin, have motivated us to develop methods for the preparation of polyamine structures. The cornerstone of our approach has relied on the selective oxidation of C--H bonds and olefins by dirhodium catalysts. Our research has involved: 1) the design of novel sulfonamide reagents, 2) explorations into the oxidizing ability of unusual metal-nitrene species, 3) reactivity and mechanistic studies involving a previously unknown class of heterocycles, 4) the development of preparative processes for the rapid assembly of diamine and polyamine derivatives, and 5) efforts towards the total synthesis of pactamycin. Nitrogen-rich molecules like pactamycin continue to challenge our inventiveness as chemists, and as a result, have led to a number of advances related to the synthesis of diamines and polyamines. All told, we feel that these discoveries demonstrate the power of Rh-catalyzed oxidation reactions for synthesizing amine-containing compounds and should prove of general use for chemical synthesis.
Rock, crowds and power [electronic resource] : race, space and ideology at American rock festivals, 1965-present
Keywords: Modern Thought and Literature.

This dissertation examines the interplay between rock crowds and power at American rock festivals from 1965 to the present. It focuses primarily on rock festivals that are held on repurposed land, that draw over 40,000, and that are literally or nominally free of charge. This project questions the utopian rhetoric that underpins these festivals and unpacks the disjunctive logic that causes audiences to take part in celebrations. Building on the assumption that these types of rock festivals are a postwar phenomenon born of advances in amplification technology and shaped by countercultural aims, it argues that the enormous longevity of this form of entertainment rests on three powerful appeals: sex, drugs, and nature, all three of which touch on American notions of liberty and freedom. But while these three ideas -- sexual liberty ("free love"), liberal drug use ("legalize pot!") and participating in nature as a regenerative idyll -- appeal to white male audiences, they serve to alienate audiences of color. This is doubly unfortunate, because the artistic content of most rock festivals rests on black pop idioms and the display of black bodies. Far from being the utopian and communal spaces of spiritual regeneration that they claim for themselves, I find that they serve mostly to display the free market to consumers in its very best light. At the same time, they may have helped link computer technology to rock music by, among other things, physically illustrating what I call "the digital diaspora, " that is, the new global routes for culture being carved out by the digitization of music.
A role for simulative mental models in science concept representation [electronic resource] : the case of instantaneous speed
Keywords: Education.

What kinds of thinking go into learners' cognitive representations of fundamental science concepts like force or ion? The work reported on here advances the broad hypothesis that there are many science concepts for which representation depends upon a special kind of thinking, depictive mental simulation, and that the representations that result from this thinking are simulative mental models. This hypothesis is developed within an empirical study of the representation of one concept in particular, instantaneous speed. The study was a true experiment with two conditions. In one condition, high school students participated in learning activities in which they engaged in a form of depictive mental simulation hypothesized to be useful for understanding instantaneous speed. In the other condition, students participated in the same learning activities except that they did not engage in depictive mental simulation. On a posttest, students who had engaged in depictive mental simulation understood instantaneous speed better than those who had not. Interpretation of these results in light of a classic set of studies in science thinking and learning leads to the broad hypothesis that depictive mental simulation plays a key role in the representation of many different science concepts. This hypothesis calls for changes in the field's conception of what it means -- and what it takes -- to teach for understanding in science.
The role of molecular elasticity in biopolymers and protein self-assembly [electronic resource]
Keywords: Mechanical Engineering

Molecular structure of many polymers including biopolymers creates elastic rigidity that impacts polymers behavior. Understanding this impact is critical to address the physics describing variety of single-molecule experiments and biological processes. Utilizing analytical theories and numerical methods, we illustrate the effect of molecular elasticity on the behavior of single molecules employed in single-molecule experiments as well as the morphology of assemblages in protein self-assembly processes. Single-molecule experiments are employed to characterize thermodynamics and kinetics of biomolecules such as DNA and RNA during biomolecular processes. In these experiments, we address the effect of thermal fluctuation, focusing on the equilibrium statistical behavior of specific class of underling single molecules, which act as semiflexible polymers, to gain insight into the physics governing their behavior. To demonstrate the role that molecular elasticity plays in protein self-assembly processes, we focus on clathrin protein, a protein recruited by the cell wall for ingesting food particles during endocytosis. We demonstrate that molecular elasticity and binding affinity have a significant impact on the versatile equilibrium and non-equilibrium assemblages occurred in clathrin protein self-assemby process. These results are essential in guiding experiments utilizing clathrin proteins in biotemplating for self-assembly of nanostructures.
The role of price primacy in the decision-making process [electronic resource]
Keywords: Business.

Price is a key factor in any consumer marketplace decision, but exposure to price information can take place at different stages of a transaction. In this dissertation, I examine the effects of early attention to price, or price primacy on the decision making process at the neural and behavioral level. In these experiments, the price of an item was shown to individuals before or after the item itself was revealed. Using functional magnetic resonance imaging (fMRI) I demonstrated that price primacy appears to alter the process by which price and product information are integrated to determine an item's value. The data supported a framework in which viewing products first caused them to be evaluated in accordance with the question "how much do I like this product?" In contrast, when viewing prices first, the evaluation process seemed to reflect the question "how much is this product worth?" Behavioral experiments were used to validate this theory as well as the specific predictions made by the patterns of neural activation found in the imaging task related to purchasing different product categories, such as hedonic or utilitarian items. In particular, I demonstrate that in the domain of bargains, by focusing individuals on monetary worth, price primacy can act to increase purchasing rates of utilitarian products.
The role of schwann cells in peripheral nerve development in zebrafish [electronic resource]
Keywords: Developmental Biology.

Myelin is a specialized sheath that insulates axons and allows for the rapid conduction of action potentials. In the peripheral nervous system, myelin is made by glial cells called Schwann cells. Whereas Schwann cells have received attention mainly because of their role in generating myelin, they play many other important roles. Using the posterior lateral line nerve in zebrafish, I have investigated two aspects of Schwann cell development. First, I demonstrate a new role for Schwann cells in repositioning peripheral nerves. Second, I find that ErbB signaling and Schwann cell proliferation are required during radial sorting, a process during which Schwann cells change their interactions with axons and reorganize the structure of the nerve itself. The posterior lateral line nerve is a prominent peripheral nerve in zebrafish that innervates sensory organs called neuromasts. I find that the posterior lateral line nerve initially grows out within the epidermis but is then rapidly transitioned across the basement membrane into the subepidermal space. Schwann cells are required for this process; in three different mutants that lack Schwann cells, the nerve is consistently mislocalized to the epidermis. This mislocalization results in significant disorganization of the nerve that worsens over time. When wildtype Schwann cells are transplanted into mutants lacking Schwann cells the position of the nerve is rescued. These results provide evidence that moving the posterior lateral line nerve out of the epidermis, across the basement membrane, protects the nerve from the migration of its targets. Before Schwann cells can make myelin around an axon, they must go through several developmental steps. Immediately after Schwann cells and axons have completed their migration, each Schwann cell associates with many axons. In order for myelination to proceed, however, a Schwann cell must associate with only a single axon. This transition, termed radial sorting, results in significant reorganization of the nerve. Neuregulin signaling from axons through ErbB receptors on Schwann cells controls many aspects of Schwann cell development and in mammals both Neuregulin/ErbB signaling and Schwann cell proliferation have been implicated in radial sorting. This prompted me to investigate whether ErbB signaling was required to regulate Schwann cell proliferation during radial sorting. To test this I took advantage of the zebrafish model system and used small molecule inhibitors to inhibit either ErbB signaling or proliferation at the time when radial sorting is beginning. I find that ErbB signaling and Schwann cell proliferation are critical for radial sorting. ErbB signaling was also required for Schwann cells to extend processes into the axon bundle, while proliferation was not. Therefore, I propose that ErbB signaling is directly required during radial sorting to regulate Schwann cell process extension, in addition to the previously established role of ErbB signaling in stimulating Schwann cell proliferation.
Roles for the human sirtuin SIRT7 in chromatin regulation and cancer [electronic resource]
Keywords: Biology.

Sirtuins are a conserved family of NAD+-dependent deacetylases that regulate diverse biological processes including genomic stability, metabolism, and aging. SIRT7 is a mammalian sirtuin whose enzymatic activity and physiologic functions have been unclear. Here I present work aimed at elucidating the biochemical, molecular, and cellular roles of human SIRT7. In Chapter 1, I report the discovery that SIRT7 possesses deacetylase activity specific for histone H3 acetylated at lysine 18 (H3K18Ac). In genome-wide binding studies, we find that SIRT7 associates with promoters of a specific set of gene targets, where it deacetylates H3K18Ac and promotes transcriptional repression. In Chapter 2, I discuss the identification of a novel SIRT7 interacting protein, the ETS transcription factor ELK4. Our work suggests that ELK4 plays an important role in defining the spectrum of SIRT7 target genes, by recruiting SIRT7 to a subset of promoters. In Chapter 3, I present our work establishing new functions for SIRT7 in cancer progression. Notably, selective hypoacetylation of H3K18Ac has recently been linked to oncogenic transformation, and in patients is associated with aggressive tumor phenotypes and poor prognosis. We find that deacetylation of H3K18Ac by SIRT7 is necessary for maintaining essential features of human cancer cells including anchorage independent growth and escape from contact inhibition. Moreover, SIRT7 is necessary for a global hypoacetylation of H3K18Ac associated with cellular transformation by viral oncoproteins. Finally, SIRT7 depletion markedly reduces the tumorigenicity of human cancer cell xenografts in mice. Together, this work establishes SIRT7 as the first known site-specific H3K18Ac deacetylase and demonstrates a pivotal role for SIRT7 in chromatin regulation, cellular transformation programs, and tumor formation in vivo.