VictorJuiz/thesis huggingface dataset:
Monolithic integration of germanium-on-insulator platform on silicon substrate and its applications to devices [electronic resource]

Due to its higher carrier mobilities and lower optical bandgap, germanium (Ge) has been considered as an attractive material for high performance CMOS and optical applications. High performance electrical and optical devices have already been demonstrated on a germanium-on-insulator (GOI) platform. To employ high performance GOI devices side by side with a silicon (Si) CMOS circuitry, monolithic integration of GOI platform on Si is needed. In this work, a lateral overgrowth technique for the monolithic integration of GOI on Si is demonstrated. Silicon dioxide (SiO2) is used as a growth mask. Ge is over-laterally grown from the growth windows defined in the SiO2 to form the GOI platform. The technique gives a high quality GOI platform. Based on the lateral overgrowth approach, lateral p-i-n photodiode with excellent diode characteristics and high optical response is demonstrated. On the lateral overgrowth GOI, p-i-n and metal-semiconductor-metal (MSM) photodiodes are demonstrated. Ge MSM photodiodes typically show high dark current, due to the strong metal Fermi level pinning. To suppress the high dark current, photodiode with metal-insulator-semiconductor (MIS) contact is demonstrated using titanium oxide as a Fermi level de-pinning layer. The MIS contact allows transport of electrons freely but blocks holes to reduce dark current.

Keywords: Electrical Engineering.
Advisor: Saraswat Krishna primary advisor. Thesis advisor
Harris J. S. (James Stewart)
Wong Hon-Sum Philip
Moonshine and SW(3/2, 2) [electronic resource]

Superstring compactification on a manifold of Spin(7) holonomy gives rise to a 2d worldsheet conformal field theory with an extended supersymmetry algebra. Such manifolds have a c=12 realization of the symmetry group SW(3/2, 2). In this thesis, I explore the characters of this algebra, and decompose the elliptic genus of a general Spin(7) compactification in terms of these characters, giving results that are suggestive of a large symmetry group. I make this suggestion manifest by constructing a SCFT that permits an M24, Co2 and Co3, and which has an action by the SW(3/2, 2) algebra.

Keywords: Physics.
Advisor: Kachru Shamit
Kallosh Renata
Silverstein Eva
Multiple testing and minimax estimation in sparse linear regression [electronic resource]

In many real-world statistical problems, we observe a response variable of interest together with a large number of potentially explanatory variables of which a majority may be irrelevant. For this type of problem, controlling the false discovery rate (FDR) guarantees that most of the selected variables, often termed discoveries in a scientific context, are truly explanatory and thus replicable. Inspired by ideas from the Benjamini-Hochberg procedure (BHq), this thesis proposes a new method named SLOPE to control the FDR in sparse high-dimensional linear regression. SLOPE is a computationally efficient procedure that works by regularizing the fitted coefficients according to their ranks: the higher the rank, the larger the penalty. This adaptive regularization is analogous to the BHq, which compares more significant p-values with more stringent thresholds. Under orthogonal designs, SLOPE with the BHq critical values is proven to control FDR at any given level. Moreover, we demonstrate empirically that this method also appears to have appreciable inferential properties under more general design matrices while offering substantial power. The thesis proceeds to explore the estimation properties of SLOPE. Although SLOPE was developed from a multiple testing viewpoint, we show the surprising result that it achieves optimal squared errors under Gaussian random designs. This optimality holds under a weak assumption on the l0-sparsity level of the underlying signals, and is sharp in the sense that this is the best possible error any estimator can achieve. An appealing feature is that SLOPE does not require any knowledge of the degree of sparsity, and yet automatically adapts to yield optimal total squared errors over a wide range of l0-sparsity classes. Finally, we conclude this thesis by focusing on Nesterov's accelerated scheme, which is integral to a fast algorithmic implementation of SLOPE. Specifically, we prove that, as the step size vanishes, this scheme converges in a rigorous sense to a second-order ordinary differential equation (ODE). This continuous time ODE allows for a better understanding of Nesterov's scheme, and thus it can serve as a tool for analyzing and generalizing this scheme. A fruitful application of this tool yields a family of schemes with similar convergence rates. The ODE interpretation also suggests restarting Nesterov's scheme leading to a new algorithm, which is proven to converge at a linear rate whenever the objective is strongly convex.

Keywords: Statistics.
Advisor: Candès Emmanuel J. (Emmanuel Jean) primary advisor. Thesis advisor
Johnstone Iain advisor. Thesis advisor
Siegmund David
Multiple views on multiple metrics [electronic resource] : how teachers perceive the validity and utility of metrics in a multi-measure evaluation system

Over the past five years, policy makers have shown a renewed interest in using teacher evaluation as a lever for increasing the quality of the teacher labor market. As such, states have been spurred by federal policies such as Race to the Top and influential foundations such as the Bill & Melinda Gates Foundation to use a more reliable, more nuanced method of evaluation: multiple metrics. Unlike relying solely on test scores or observation checklists, these new composite metrics were touted as more stable estimates for both human resource decisions and for targeting professional development. These multiple measures vary from district to state, but they are largely a combination of growth-based student test metrics, standards-based observation metrics, and surveys from stakeholders such as students or teachers. This study focuses on a state that uses the former two metrics, student growth and teacher observation, to ask whether such metrics are providing information to teachers that they can use to inform their instruction. This mixed-methods study takes place in Delaware, which was the first winner of President Obama's federal education initiative, Race to the Top. As such, it won

Keywords: Education.
Advisor: Grossman Pamela L. (Pamela Lynn)
Borko Hilda advisor. Thesis advisor
Loeb Susanna advisor. Thesis advisor
Multiplexed immuno-magnetic enrichment of cells and downstream molecular analysis [electronic resource]

This thesis is about the characterization, and applications of the magnetic sifter. The magnetic sifter is a microfabricated cell separation device that enables high throughput cell separation with good capture and release properties. The unique magnetic and fluidic properties of the magnetic sifter that contribute to its unprecedented capture and release performance are discussed based on finite element analysis, and experimental characterization. In addition, this thesis will also cover the extension of the magnetic sifter towards accomplishing multiplexed magnetic separation. In particular, it will be shown how judicious manipulation of the competing magnetic and hydrodynamic forces, the dominant factors in the magnetic sifter, allow for multiplexing by a variety of methods. Lastly, this thesis will also expand on the various downstream molecular methods that have been shown to integrate well with the magnetic sifter. It shall be made evident that the magnetic sifter causes no adverse effects in the phenotype of the isolated cells, and that various downstream molecular analysis methods all combine well with the magnetic sifter. Data is presented for all these methods, and will illustrate the potential the magnetic sifter has, for various clinical applications in the near future.

Keywords: Chemical Engineering.
Advisor: Swartz James R. primary advisor. Thesis advisor
Wang Shan
Dunn Alexander Robert advisor. Thesis advisor
Mutual Fund Age, Performance, and the Optimal Track Record

This paper investigates the relationship between mutual fund age and performance, and what this might imply about the track record that investors should require when evaluating mutual funds. While this relationship has been explored mostly through the lens of performance persistence, primarily by Berk and Green (2004), the age/performance relationship alone is still relatively unexplored, particularly in regard to new funds. This relationship has significant implications for the decisions of mutual fund investors. If age and performance have a negative correlation, then waiting several years for a mutual fund to establish a track record before investing may be unwise, as the fund’s best performance will already be behind it. In this paper, I utilize data from the CRSP mutual fund database to quantify the age/performance, age/risk, and age/risk-adjusted performance relationships for Morningstar’s listed U.S. equity funds. I conclude that in general, older funds are riskier, but this relationship reverses for very young funds, which exhibit more risk. I also find that older funds have slightly lower risk-adjusted returns, but this relationship again reverses for very young funds. Though both of these relationships are somewhat weak, my results imply that investors may not want to flock to new funds in the hope of outsized riskadjusted returns—requiring a track record does not come at a significant cost and may, in fact, help investors avoid undue risk.

Keywords:  Department of Economics
Stanford Department of Economics
mutual fund performance
age and performance
Morningstar funds
Thesis
Advisor: Shoven John
Piazzesi Monika
MYC and RAS induce lipogenesis in lung cancer and generate distinct tumor subtype lipid signatures

Lung cancer is the deadliest type of cancer and a cure for advanced stages of this disease does not currently exist. MYC and KRAS are two oncogenes commonly implicated in the development and maintenance of lung cancer. Emerging evidence has revealed that lung cancer reprograms cellular metabolism and previous studies have demonstrated that MYC and KRAS alter glucose and glutamine metabolism as a means of supporting cancer cell survival. However, the role that MYC and KRAS play in lipid metabolism in lung cancer has not been addressed. Here, preliminary data using Desorption Electrospray Ionization Mass Spectrometry Imaging (DESI-MSI) for lipid profiling of lung tumor tissue as well as gene expression analysis of key lipogenesis genes show that MYC and KRAS not only induce lipogenesis in lung tumors but do so through distinct pathways. Additionally, by administering inhibitors of enzymes involved in the fatty acid synthesis pathway to human lung cancer cell lines, I demonstrate that blocking lipogenesis reduces the proliferation of lung tumor cells in vitro. These results suggest that lung tumors are dependent upon oncogene-induced lipogenesis and that inhibition of lipogenesis pathways may be a promising therapeutic approach for the treatment of lung cancer.

Keywords:  Department of Biology
Biology
MYC
KRAS
RAS
oncogene
metabolism
lipogenesis
lung cancer
Thesis
Advisor: Felsher Dean
Gozani Or
Myelination of the brain in major depressive disorder [electronic resource] : an in vivo magnetic resonance imaging study

Major depressive disorder (MDD) is a debilitating psychiatric condition and a leading contributor to the global burden of disease. Characterizing MDD-related abnormalities in neurobiological processes will inform more comprehensive etiological frameworks of MDD that will facilitate the development of more targeted approaches to the prevention and identification of, and intervention for, this disorder. In this context, one promising biological target is myelin, a specialized biological tissue and fundamental facilitator of neuronal communication. Myelin ensheaths axons and facilitates saltatory conduction of electrical signaling in the nervous system. Postmortem studies of brains of depressed individuals, and non-human animal, genetic, and neuroimaging studies suggest that abnormalities in myelin are associated with MDD. Growing evidence suggests that neural activity and myelin influence each other to support an effective nervous system, and that stress-related neuroinflammation may result in the degradation of myelin in MDD. Brain regions implicated in this research, and in MDD more generally, include the nucleus accumbens (NAcc) and the dorsolateral prefrontal cortex (DLPFC), core regions involved in reward and cognitive control processes, respectively. Recent developments in quantitative magnetic resonance imaging (qMRI) allow for improved assessment of myelin content at the whole brain level, in vivo, in humans through the measure of R1. In this study we used qMRI to measure R1 to examine whether the brains and, in particular, the NAcc and DLPFC, of individuals diagnosed with MDD are characterized by reductions in myelin content compared to individuals without a history of psychiatric disorder (i.e., healthy controls [CTLs]). We found that the MDD group had lower levels of myelin than did the CTL group at the whole brain level and in the NAcc. Furthermore, myelin content of the DLPFC was reduced in MDD participants who had experienced a greater number of depressive episodes compared to both MDD participants who had experienced fewer depressive episodes and participants in the CTL group. Taken together, these results offer new evidence that MDD is characterized by reduced myelin content of the brain and in the NAcc in particular, and that the chronicity of MDD is associated with reduced myelin in the DLPFC. While further research is needed to elucidate the role of myelin in influencing affective, cognitive, behavioral, and clinical aspects of MDD, the current study provides important evidence that a fundamental property of brain composition, myelin, is altered in this disorder.

Advisor: Gotlib Ian H.
Wagner Anthony David primary advisor. Thesis advisor
Gross James
Knutson Brian advisor. Thesis advisor
Malenka Robert C.
Nanoscale reaction, transport, and phase transformation in LixFePO4 battery electrodes [electronic resource]

Interfacial reaction, transport, and phase transformations are the primary mechanisms by which materials change. Understanding these processes, especially on the nanoscale, is key to understanding how material properties change through external physical and chemical stimuli. To obtain a holistic understanding, it is also necessary to study how these mechanisms are coupled to one another. The lithium-ion battery is an ideal model system for studying the coupling of reaction, transport, and phase transformations on the nanoscale. Not only do batteries use all three mechanisms during charge and discharge, it is also possible to precisely control the lithium composition, an extrinsic variable, at the nanoscale by controlling the electrochemical current. Fundamental studies of Li-ion battery materials, especially phase transforming ones, are hindered by the porous electrode architecture. Such porous electrodes contain an ensemble of nanoparticles with nonuniform electronic and ionic connectivities. With heterogeneous current densities and lithium compositions, it is very difficult to correlate macroscopic current-voltage or structural measurements to microscopic, single-particle phenomena. My thesis overcomes this problem by using nanoscale imaging study individual battery particles. By being able to probe the lithium composition and current density of single battery particles on the nanoscale, I obtain a local, microscopic measurements of reaction, transport, and phase transformation dynamics. While I initially conduct these experiment ex situ by cycling and disassembling the battery electrodes, I also develop in situ techniques that enable me to track the evolution of the lithium composition and current density on the nanoscale as the battery charges and discharges. I specifically aim to understand four different ways that reaction, transport, and phase transformation are coupled on the nanoscale. First, I study how transport at the porous electrode affects reaction and phase transformation within individual particles. Second, I investigate how ion insertion reaction rate affects the phase transformation pathway. Third, I examine how the lithium composition and phase affects the ion insertion reaction rate. Finally, I study how diffusion affects the ion insertion rate. I developed a coherent model that quantitatively explains how the rate of ion insertion reaction and the rate of diffusion ultimately affect the phase transformation pathway, both within individual battery particles and in a many-particle electrode. This model shows how reaction, transport, and phase transformation are coupled together to determine how this battery electrode undergoes charge and discharge.

Keywords: Materials Science and Engineering.
Advisor: Chueh William
Cui Yi
Salleo Alberto
Narratives of collective belonging [electronic resource] : American Jews and the history of Israel

Article I explores the way a diverse sample of American Jewish parochial school students narrated the history of Israel. It analyzes 438 responses to the prompt: "In 2-3 paragraphs, tell the history of the State of Israel as you understand it." The students' responses suggested that many students are aware of the tensions between various historical accounts and adopt different strategies to negotiate between critical historical analysis and Jewish collective belonging. Although there were no differences in the content of the accounts by students' religious denomination or prior study of Israel's history, students adopted different approaches to negotiating critical analysis and collective belonging. Some students told stories of Jewish heritage without taking into account other possible perspectives. Some students engaged with challenges to their inherited stories but only to dispute them. Finally, some students managed to synthesize multiple narratives together while still using a Jewish perspective to frame their account. This last strategy suggests that students can be historically sophisticated without abandoning a commitment to their heritage. Article II examines changes to Jewish parochial students' narratives of the history of Israel after a two and a half week trip there. Seventeen students were interviewed about the history of Israel before and after a two and a half week class trip. Before the trip, most students' accounts lacked logical connections among the different events. Instead, students listed events in chronological order like a timeline. The observations on the trip revealed that the tour guide told a story of Jewish exile and return. After the trip, most students adopted the tour guide's narrative structure of Jewish exile and return. This finding suggests that short trips to Israel may be able to teach a coherent narrative, something formal history classrooms struggle to do. At the same time, it raises questions about the appropriate role of narrative frameworks in history education: to what extent is it possible to teach a narrative framework and still leave room for student inquiry? Article III traces the emergence of anti-Zionism in the American New Left before 1967. Most existing research sees contemporary anti-Zionism as a reaction to Israel's occupation of the West Bank and Gaza after the 1967 War. This article finds the roots of anti-Zionism in the racially charged rhetoric of Malcolm X and the Nation of Islam in the early 1960s. It argues that particular individuals influenced by Malcolm X and even working in his Organization for Afro-American Unity carried his ideas into the Student Non-Violent Coordinating Committee, which published a harshly anti-Zionist newsletter in the summer of 1967 just after the end of the war in the Middle East. From SNCC, this racial interpretation of Zionism spread into the New Left.

Keywords: Education.
Advisor: Wineburg Samuel S. primary advisor. Thesis advisor
Kelman Ari
Zipperstein Steven J.
Navigate, read, construct [electronic resource] : supporting immigrant children to comprehend English texts

This study examined what strategies immigrant children use when trying to comprehend English texts, and how such children could be taught more effective strategies. Six children between the ages of 8; 7 and 11; 1 participated in the study; all were native speakers of Spanish who had moved to the United States no earlier than one year prior to the start of the study, and all attended the same elementary school in northern California. I used educational design research to plan, implement, and evaluate a plan for instruction for these students, and conducted periodic clinical interviews to learn about the children's approaches to comprehending English texts. Analytical induction was used to uncover patterns in the interview data, and these patterns were linked to instructional antecedents through review of teaching logs and notes on videos of the lessons. I found that all students, regardless of the amount of experience they had with English, had multiple strategies for drawing meaning from English texts. When hunting for answers in an article, they followed a universal pattern of navigating to a promising section of the text, reading it through words or pictures, and constructing a complete answer that went beyond parroting the text. Students' strategies for accomplishing these tasks changed over time, and many of their changes can be directly linked to lessons taught in class. Some strategies worked better for students with more exposure to English and proved to be inappropriate for children with less English experience. These findings have implications for the design of programs to support the burgeoning population of newcomer students in the United States.

Keywords: Education.
Advisor: Hakuta Kenji primary advisor. Thesis advisor
Aukerman Maren (Maren Songmy)
McDermott Ray (Raymond Patrick)
Valdés Guadalupe advisor. Thesis advisor