VictorJuiz/thesis huggingface dataset:
Coordinated regulation of neonatal beta-cell development in mice and humans by calcineurin/NFAT [electronic resource]
Keywords: Developmental Biology.

To meet host metabolic demands after birth, organs like pancreatic islets increase their physiological function and mass. Compared to fetal islet development, however, little is known about mechanisms governing neonatal islet maturation and expansion. Here I demonstrate calcineurin/Nuclear Factor of Activated T-cells (Cn/NFAT) signaling regulates both [beta]-cell maturation and proliferation in neonatal mice and humans. Inactivation of the gene encoding the calcineurin phosphatase regulatory subunit, calcineurin b1 (Cnb1), in mouse islets resulted in defective dense core granule biogenesis, impaired insulin secretion, and reduced neonatal [beta]-cell proliferation and mass, culminating in lethal, early-onset diabetes. [beta]-cells lacking Cnb1 failed to express genes required for insulin storage and secretion, as well as neonatal replication. Tacrolimus, a calcineurin inhibitor and widely used immunosuppressant, reduces human [beta]-cell secretion and promotes diabetes, toxicities without a clear molecular basis. Exposure of mouse and human islets to tacrolimus reduced expression of genes encoding factors essential for insulin dense core granule formation and secretion, and neonatal [beta]-cell proliferation consistent with our genetic studies. Chromatin immunoprecipitation and other molecular studies revealed these genes as novel, direct NFAT targets in neonatal mouse and human islets. Thus, calcineurin/NFAT signaling coordinately regulates factors that govern [beta]-cell maturation and proliferation, revealing unique models for the pathogenesis and therapy of diabetes mellitus and diverse human islet diseases.
Coping with challenges in middle school [electronic resource] : the role of implicit theories of emotion
Keywords: Psychology.

The ability to cope with challenges predicts functioning across a wide range of domains. One factor that has been shown to predict functioning is people's implicit theories — their beliefs about the malleability of personal attributes. The current research presents four studies that examine implicit theories of emotion during the challenging middle school period. Studies 1 and 2 compared the relationship between emotion theories and emotional functioning with the relationship between intelligence theories and academic functioning in a sample of 115 middle schoolers. Consistent with past research, Study 1 found that intelligence theories predicted academic functioning during the challenging transition year in middle school. Sixth graders with an incremental theory of intelligence earned higher grades than students with an entity theory. Extending past research, Study 1 found that emotion theories predicted emotional functioning. Sixth graders with an incremental theory of emotion reported fewer depressive symptoms and greater well-being. Further, Study 1 found that intelligence theories and emotion theories predict functioning through similar processes. Students with an incremental theory of intelligence valued effort more, and their effort beliefs mediated the relationship between an incremental theory and higher grades. Similarly, students with an incremental theory of emotion used more adaptive emotion regulation strategies, specifically reappraisal, and reappraisal mediated the relationship between an incremental theory of emotion and both fewer depressive symptoms and greater well-being. Study 2 followed the students from Study 1 through the end of the middle school period and found that implicit theories predicted students' trajectories throughout middle school. Students with an incremental theory of intelligence in sixth grade were more likely to move to advanced math courses over time. Similarly, students who began sixth grade with lower well-being were more likely to feel better over time if they reported having an incremental theory of emotion in sixth grade. Since Studies 1 and 2 were the first studies to explore emotion theories in middle school students, Study 3 examined emotion theories in a larger, more heterogeneous sample. In a sample of 1,353 sixth through eighth graders, an incremental theory of emotion predicted more reappraisal use, less misery, and greater well-being. Further, reappraisal mediated the relationship between emotion theories and emotional outcomes. Finally, Study 4 taught students an incremental theory of emotion and reappraisal use through a brief, online intervention. Students who were randomly assigned to the treatment condition reported more incremental theories of emotion and greater use of reappraisal several weeks after the intervention. If long-term follow up of these students shows a positive and lasting impact on emotional outcomes, an emotion theory intervention can be a powerful tool to set students on positive emotional trajectories.
Copper sulfide resistance change memory and its scalability [electronic resource]
Keywords: Electrical Engineering.

The increase of portable electronic devices such as cellular phones, digital cameras, and mp3 players is driving a rapid growth of the market for nonvolatile memories (NVMs). Today's most established NVM technologies are based on charge storage method. However, the scaling of current NVM technologies beyond 32 nm node of International Technology Roadmap for Semiconductors (ITRS) poses severe problems such as poor retention and unacceptable cross-talks among devices. To overcome these disadvantages and achieve high-speed, high-density, long-retention, and low-power NVMs, several new memory materials and technologies have been extensively investigated. Among new emerging materials and concepts, we investigate copper sulfide resistance change memory, which is one of the most promising candidates for future NMV, whose electrical resistance can be changed reversibly between two stable states. In the first part of the study, we report fabrication and electrical characterization of micrometer-scale copper sulfide NVM devices. We have achieved synthesis of stoichiometric Cu2S using anodic polarization whose composition is analyzed by Rutherford backscattering (RBS), and fabricated [micrometer]-sized NVM devices in the sandwiched structure of a Cu/Cu2S/top electrode. The resistive switching is consistent and reproducible over 50 cycles for large-area devices and 200 cycles for small-area devices. Low SET and RESET voltages below 0.3 V for switching and a high OFF-state resistance to ON-state resistance ratio over 10^5 have been achieved. The ON-state resistance value, RON, does not change as the size of the devices shrinks indicating the conduction is localized while the OFF-state resistance, ROFF, increases with the device scaling. As a result, we can obtain a fascinating scaling result that ROFF/RON ratio increases as the devices scale down. In the second part of the study, we present for the first time a simple fabrication method of copper sulfide nanopillar arrays with a high aspect ratio using nanoporous templates created from self-assembled nanostructures of block copolymers (BCP) for NVM applications. With our proposed process, the high aspect ratio of copper sulfide nanopillars with 25 nm in diameter and 170 nm in height is generated. Due to the small distance of 40 nm between the nanopillars, characterization is performed using conductive atomic force microscope (CAFM). Our nanopillar arrays exhibit a huge ROFF/RON ratio of 10^7 at a 2 [microampere] current level. This low level of switching current demonstrates the possibility of low-power NVM devices.
Corporate performance in light of congressional conflicts of interest [electronic resource]
Keywords: Business.

While members of Congress must disclose information about their financial assets, there are no restrictions on the types of assets they can hold. This creates conflicts of interest as legislators vote on issues that will affect their personal investments. This dissertation explores the shareholder relationships between members of Congress and the corporations in which they are invested. I begin by examining how they allocate their investments. I use the S& P 500 as a benchmark portfolio to show that legislators' portfolios do not diverge widely from the rest of the market, with a few notable exceptions. In particular, I find mixed evidence that legislators allocate investments to sectors in which they have increased influence. I then assess whether assets issued by firms in which members of Congress have financial stakes yield higher returns than those from otherwise similar firms. I provide several theoretical explanations that would support a finding of excess returns and find no evidence to suggest that firms with congressional shareholders outperform their peers. If anything, the firms with political connections perform slightly worse. This result holds over both long- and medium-term time horizons and is robust to differentiating asset holdings by party, leadership positions, or committee assignments. Lastly, I test whether markets expect these shareholder connections between politicians and firms to be valuable. I conduct three event studies using narrow elections, the public release of the financial disclosure reports, and sudden resignations of members of Congress to demonstrate that market participants do not expect firms with congressional ties to outperform their peers.
Correlation analyses of encoded music performance [electronic resource]
Keywords: Music.

Correlation analyses of encoded music performance by a large and diverse international community of amateur performers afford insights into fundamental questions of musical behavior. By observing demographic data associated with a corpus of performance recordings, we can conjecture about cultural, geographical, topographical, socio-political, economic and other potential influences, and explore possible 'universals' in musical thought and practice. This study attempts to address questions of musical practices from an entirely novel perspective, specifically taking advantage of massively popular game-oriented music performance programs on mobile devices.
Cosmological Evolution of Gamma-Ray Bursts
Keywords:  Department of Physics
gamma-ray bursts
cosmology
high-energy astrophysics
Thesis

Gamma-ray bursts (GRBs) are among the most powerful electromagnetic events in the universe, luminous enough to be detected across vast stretches of space and time. This makes them invaluable cosmological probes of the early universe. However, to use GRBs as probes, we must first determine the evolution of their characteristics, such as the co-moving density rate and the luminosity function. This process is complicated by an extensive collection of observational biases, truncations, and questionable assumptions about the parametric forms of the various functions. We apply non-parametric methods, developed by Efron & Petrosian for truncated data, directly to a sample of Swift long GRBs with known redshifts, and obtain the co-moving density rate evolution and luminosity function and evolution. Furthermore, we derive a GRB rate which is very different from star formation rate, particularly below redshift z~2, indicating perhaps a distinct class of low-z GRBs.
Covalent modification of mRNAs in S. cerevisiae [electronic resource]
Keywords: Biochemistry.

While the presence of modified nucleotides in cellular RNA has been known about for over 60 years, it is only recently that such nucleotides have become studied and mapped in mRNAs. With recent transcriptome-wide maps of N6-methyladenosine and 5-methylcytosine showing widespread mRNA modification and evolutionary conservation of many sites, it is clear that site-specific mRNA modification may represent a new level of post-transcriptional regulation of gene expression. With this in mind, we set out to map other mRNA modifications to begin to get an idea of the role they may play in gene expression. We developed a high-throughput sequencing technique that identified the first known pseudouridines in mRNA. We were able to identify the enzymes that modified a few of the top hits, as well as show that modification of at least one of the top sites is conserved throughout the fungal lineage. We have made progress toward developing an improved high-throughput sequencing technique, which could allow elucidation of a transcriptome-wide map of pseudouridines. Adapting the same technique as was used to identify mRNA pseudouridylation, we also found a few dozen possible 2'-O-methylation sites in mRNA with an interesting functional theme, though these potential modifications still need to be validated. In addition, we attempted to map and find a functional role for N6-methyladenosines in yeast undergoing meiosis, and while this failed, it led to our discovery of a target set of bound mRNAs and role in gene expression of a meiosis-specific RNA binding protein, Rim4p. The work described in this thesis identifies the third known internal, site-specific modified nucleotide in mRNA, suggesting that mRNA modifications may be more common than previously thought and may play an important, under-explored role in post-transcriptional control of gene expression.
Creating effective magnetic field for photons [electronic resource] : principles and applications
Keywords: Physics.

In this dissertation, I present the results of study of creating effective magnetic field for photons. I will show two routes to achieve such a goal: dynamic modulations and magneto-optic effects. The essence of the dynamic modulation scheme is that the phase of dynamic modulations can be related to an effective gauge potential for photons. Such an identity is exclusively demonstrated through a photonic Aharonov-Bohm effect. Based on this observation, when a two-dimensional photonic resonator lattice undergoes dynamic modulation, photons propagating in this lattice experience an effective magnetic field. The consequence of the achievement of effective magnetic field for photons is two-fold. On one hand, one can generate photonic phenomena that are reminiscent to the electronic correspondence, which is intellectually fascinating. In particular, I will show a photonic de Hass-van Alphen effect, and a photonic quantum Hall effect with one-way edge modes. On the other hand, effective magnetic field and effective gauge potential bring in new ingredients to the control of light propagation, which is of practical importance. I will numerically show concrete examples of such flexible, non-reciprocal light propagation effects using effective magnetic field, including negative refraction, one-way mirror, as well as on- and off-axis focusing in a same resonator lattice under dynamic modulation.
Crisis decision analysis [electronic resource] : how to save more lives?
Keywords: Management Science and Engineering.

A crisis creates a decision situation in which it is challenging to apply decision analysis as a normative decision-making approach. The existing literature on crisis decision making lacks discussions on three aspects developed in this dissertation: (1) how a crisis decision maker can prepare for crisis responding decisions; (2) how to determine the optimal timing of actions balancing the quality of information against the effectiveness of intervention; and (3) how to handle unexpected new observations. Chapters 3, 4, and 5 develop and characterize a set of tools for structuring, making, and updating strategic decisions when responding to a variety of crises. A "Crisis World Map" is a conceptual map customized for each individual crisis decision maker. Such a tool helps clarify the boundaries of what can be planned and what cannot before crises happen, and therefore helps prepare for crisis responding decisions. The second tool incorporates time into the decision analysis model and helps the decision maker describe time-varying values and probabilities. As a result, the decision maker can more effectively balance the trade-off between waiting for more information versus taking quick actions in moments of crisis. When unexpected new observations arise before the decision maker takes actions, the "Value of Further Modeling" helps him decide whether to introduce new uncertainties that potentially change the decision. Chapter 6 and Chapter 7 examine two historical case studies in detail. One case study is on the 1999 United Nations Peacekeeping mission planning for Sierra Leone and the other is on the 2011 Fukushima nuclear crisis. Although the two case studies discuss completely different types of crisis under different time scales with different sources of value, they both provide concrete validation of the proposed methodologies and generate many valuable practical insights for application.
Current- and wave-driven flow and nutrient exchange in natural and model submerged vegetated canopies [electronic resource]
Keywords: Civil and Environmental Engineering.

In the coastal ocean, seagrass canopies attenuate near-bed current velocities and modify flow in the region above. In so doing, they help to reduce sediment erosion and resuspension. Vertical profiles of mean water velocity and key turbulent quantities have characteristic features that indicate these underlying dynamics. While such profiles have been especially studied well in the laboratory, detailed measurements are rare in natural seagrass canopies. We addressed that deficiency with a comprehensive set of natural canopy flow measurements, analyzed in the context of the laboratory-derived models. Seagrasses depend on these hydrodynamic interactions for their health and basic biological functions. The rates of many of their core metabolic processes are limited by nutrient availability; in many environments, availability is constrained most by the slow diffusive transfer across element boundary layers. Boundary layer thickness is reduced by flow, and evidence has shown that seagrass nutrient uptake rates rise as mean water velocities are increased. However, uptake rates are enhanced even more significantly in wave-driven, oscillatory flows - flows that are less effectively attenuated within the canopy space. In another portion of the work described here, we measured flow-modulated seagrass community uptake directly in both current-driven and wave-driven flow. We found that uptake rate efficiency depends not just canopy depth-averaged flow magnitude, but also on the characteristic wave frequency. Finally, we found that at some field locations, flexible canopy-forming seagrasses were complemented with a dense understory of secondary species. In wavy-environments, understory biomass may fill distinct ecological niches while also helping to protect the bed from wave-driven disturbances. We created a simple numerical model to encapsulate the theory, and tested it in the laboratory with a collection of heterogeneous canopy mimics. Results supported the idea that understories may indeed significantly alter near-bed hydrodynamics.
Data-driven instructional leadership and the necessity of relational trust [electronic resource] : a case study in principal leadership
Keywords: Education.

This case study of a small high school demonstrates the effects of principal leadership dispositions and activities on relational trust within a school community and especially between the principal and school faculty. Through an analysis of evidence from site observations and interviews of classroom teachers and site administrators over three school years, the author concludes that the school-based outcomes of data-driven instructional leadership correlate with extant levels of relational trust among faculty, and correlate with the principal's approach to collecting and employing data during the process of school reform. Teacher reports of instructional reform activities as well as student standardized test outcomes and teacher retention data all support the conclusion that teachers are more engaged in professional improvement, work longer days and weeks voluntarily, and adopt a "whatever it takes attitude" towards school reform when led by a principal who builds relational trust by collecting and using data to support teacher professional development, communicate respect for teachers and augment teacher voice and inclusion in site-based decision-making.
Decentralized control and the analysis of electrical distribution systems [electronic resource]
Keywords: Electrical Engineering.

This thesis studies the design and analysis of decentralized control over stochastic nonlinear systems. Different from the traditional centralized control, decentralized control considers multiple controllers, each with different information structure, actuating a system collaboratively. The thesis is composed of two parts. In the first part, we analyze the system stability of a distribution system with inverter-connected distributed power generation. Inverters are decentralized in nature. They are only allowed to communicate through local system measurements in voltage and current. No direct communication exists between these inverters. This convention of inverter control is nonlinear in the measured voltage and current. This work analyzes how the control policy of droop inverters affects the existing grid, and the robustness of the closed-loop system under disturbances. In the second part, we consider a theoretical problem in decentralized control over an adversarial network. We consider a networked system built on top of unreliable channels. These channels suffer from random information loss. The actuation signal of controllers are carried over a TCP-like protocol. In particular, we consider the sparsity information structure of controllers that are quadratically invariant. The problem is first formulated into a partially observable Markov decision process (POMDP). From the perspective of a fictitious player, we transform this decentralized problem into a centralized problem, which allows us to synthesize an optimal control policy with Kalman filters and value recursions.
Decision analysis for the optimal treatment of limb threatening leg injuries [electronic resource]
Keywords: Management Science and Engineering.

Limb threatening trauma to the leg may be treated with either limb salvage (retention process) or amputation (prosthetic process). Limb salvage allows the patient to keep his leg and avoid using a prosthetic; however, it typically has higher probabilities than amputation of complications, additional time in the hospital, and chronic pain. The optimal treatment is still under debate and the current methods to make the decision do not explicitly incorporate the patient's preferences or the patient's medical insurance. This dissertation develops a decision analysis model to help a patient think clearly about the retention process vs. the prosthetic process. The model updates conditional probabilities of various outcomes based on the patient's demographics and develops a method to explicitly incorporate the patient's preferences for keeping the leg, avoiding chronic pain, and avoiding time in the hospital. The model also calculates the probabilities of hospital and prosthetic costs for the patient's health insurance and risk attitude. The decision analysis model in this dissertation utilizes preferences from the patient to inform the decision, facilitates effective discussions between the doctor and the patient, and provides a comprehensive recommendation to the patient.