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Essays in Corporate Governance
Get PDFThis thesis consists of two essays that deal with institutional investors and corporate governance. In particular the first chapter studies the relationship between higher temperatures and institutions’ proxy voting. Analyzing voting decisions by U.S. mutual funds, I find that heat exposure negatively correlates with voting against management. The findings concentrate on companies or shareholder proposals where a stockholding in the firm represents a larger share of an institution’s portfolio. The heat-voting relationship is stronger when an institutional shareholder is experiencing unusually hotter temperatures. My results suggest potentially significant but hidden corporate governance implications of climate change. The second chapter studies the association between institutions’ attention to individual stocks and their active ownership positions. We find that institutions tend to vote in ways suggesting greater attention to stocks where they hold a larger active position. This association holds for institutions where voting decisions are centralized governance, including “The Big Three,” and is larger for illiquid stocks, where institutions’ active funds are less able to exercise governance via exit. Our findings suggest that passive institutions’ actively managed holdings enhance their incentive to be engaged stewards
Fabrication of Two-Dimensional Material-based Nano-Capacitors using Bismuth Selenite (Bi2SeO5) to Study its Dielectric Properties
Get PDFIn recent years, the demand for high-performance micro and nanodevices has surged, necessitating the exploration of novel dielectric materials to replace conventional silicon dioxide. Following the continuation of the Moorse law, as device dimensions reduce to nanoscale levels, the properties of silicon dioxide can degrade, leading to issues such as increased leakage current and reduced gate control. Materials with superior electrical properties, such as higher dielectric constant, lower leakage current, and better thermal stability allowing for the development of faster, more efficient, and more reliable devices are in higher demand than ever. Two-dimensional layered semiconductor nanomaterials represented by compounds such as bismuth selenite (Bi2SeO5) have promising potential due to their unique electrical and mechanical properties. In contrast to the conventional micro and nanoelectronic devices that use silicon-based dielectrics, bismuth selenite’s high-k dielectric property can allow the fabrication of devices that can store more electric charge and can help with reduced power consumption, increased speed, and overall improvement of the device performance. The high dielectric value for Bi2SeO5 can open the possibility of overcoming the challenges faced during the scaling of sub-ten nanometer technology for ultrathin silicon channels. Motivated by a recent academic paper where bismuth selenite is suggested as an alternative dielectric material with a high dielectric constant ‘k’ value of 16, this paper investigates the reproducibility of these claims. In this paper, we explore the fabrication process for two nanocapacitors using bismuth selenite as a part of the dielectric stack and compare the extracted dielectric values to the findings from the recent academic literature. We find that the dielectric constant across two fabricated devices were 3.5 and 4.1 respectively, and did not align with the claims from the academic literature. The device fabrication is an attempt to explore nanofabricated capacitors with the potential of lowering the gate voltage, more efficient gate-field penetration, and power consumption in 2D electronics and integrated circuits
Numerical Simulation of Subsonic and Transonic Benchmark Cases with Small Regions of Separation Using Various Turbulence Models
No full textTurbulence models play an important role in including the effect of turbulence in numerical simulation of turbulent fluid flows using the Reynolds-Averaged Navier-Stokes Equations of computational fluid dynamics (CFD). In this thesis, the performance of various well-known turbulence models, namely the Spalart-Allmaras (SA), Shear Stress Transport (SST) k-ω, and Wray-Agarwal (WA) models is examined by considering the external subsonic flow over three benchmark cases: (a) the Boeing bump, (b) the two-dimensional VT/NASA bump (BeVERLI hill), and (c) the three-dimensional VT/NASA bump, and the transonic internal flow in Sajben diffuser. The flow field in all these four test cases is characterized by a small region of separation behind the bump or due to shock/boundary layer interaction in the case of diffuser. One key goal of the investigation is to evaluate the performance of a relatively new WA model compared to the established SA and SST k-ω models. The commercial flow solver Ansys Fluent is employed in the computations. The results indicate that while all three turbulence models provide acceptable predictions, the WA model demonstrates superior performance in capturing the separation region in the three external flow cases, and the internal flow field and shock position in case of transonic flow in Sajben diffuser. Moreover, the WA model also exhibits advantage in that it is less dependent on the grid density. This study demonstrates the challenges in turbulence modeling for predicting the smooth body flow separation using the RANS equations and demonstrates the potential of the WA model as an accurate and efficient model for predicting external and internal turbulent flows
Mechanical Property and Phenotype Characterization of an in vitro Model for Afterload-triggered Cardiac Hypertrophy
No full textHypertrophic Cardiomyopathy (HCM) is an inherited cardiomyopathy disease that affects approximately 1 in 500 to 1 in 200 people. Although abundant evidence has shown that HCM is related to sarcomere genetic mutations, recent research has also revealed that conditions that increase cardiac afterload, like obesity and hypertension, worsen HCM patients’ prognosis. Among research models of HCM, in vitro models that use patient-derived induced pluripotent stem cell (iPSC) differentiated cardiomyocytes are especially promising because the unlimited supply of iPSC can allow many studies to be performed under reproducible conditions. In prior studies of afterload-related phenotypes in HCM and other iPSC-based heart disease models, soft substrates like Polydimethylsiloxane (PDMS) or hydrogels have been used as stiffness matrix. However, these substrates that have constant mechanical properties have the disadvantage of being unable to mimic dynamic changes in cells’ environment that happen in the body as a result of hypertension Thus, magnetorheological elastomers (MREs), which change their stiffness in response to magnetic fields, have been developed as a next-generation substrate for cardiac mechanobiology studies. In this thesis, I characterized how the mechanical properties of MRE vary with respect to substrate geometry, and I am currently in the process of applying these substrates to study how cardiomyocytes and cardiac fibroblasts respond to dynamic stiffness changes. To characterize the mechanical properties and get the highest stiffness range of MRE substrates that we use in our in vitro model, Indentation testing and shear testing were performed on MREs with different dimensions and densities of magnetic-responsive iron particles. For the characterization of the shear modulus, I developed a custom method to replace rheology. I also verified the cytocompatibility of MREs. I am currently using MREs with iPSC-cardiomyocytes and primary cardiac fibroblasts to study how dynamic mechanical loading affects cellular hypertrophy. As a result, Higher magnetic particle doping weight percentage and higher magnetic fields increased MRE stiffness. In contrast, MRE thickness did not affect the shear modulus upon magnetization. Finally, the MREs were proven non-toxic to cells, and representative images of the immunostaining of the cardiomyocytes were acquired. Based on this, we are aiming at doing some preliminary studies on pathological phenotypes of heart disease (e.g. cell hypertrophy) with cardiomyocytes under increased afterload
Reading Mood in the Post-Oslo Palestinian Novel: Shame, Melancholy, Hope
Get PDFModern Palestinian literature was born diasporic. Produced from different positions in the Palestinian diaspora, multilingual Palestinian literature maps itself onto Palestinianess as a state of mind. In dialogue with affect theory, the dissertation supplements this understanding of Palestinianness with an account of mood in post-Oslo Palestinian literature. Specifically, I analyze shame in Ayman Sikseck’s Hebrew novel Tishrin (2016) and melancholia in Adania Shibli’s Arabic novel Minor Detail (2020 [2017]). By “reading the mood,” this dissertation examines how iltizam (commitment) in Palestinian literature registers the social and political ruptures that the collapse of the Oslo accords brought upon the Palestinian experience
Synergistic Exploration of Spin Glass Physics and Optimization Algorithm Design
Get PDFIn the past decades, enormous effort has been devoted to the study of low-temperature spin glasses. The undertaken approaches were primarily of two different types. On one hand, various theoretical pictures aimed to capture the essence and rationalize the quintessential physical features of spin glass systems. On the other hand, much work was spent on the design of various algorithms in the hope of finding efficient numerical methods for calculating the ground state or sampling excited states. The latter endeavor has ramifications in fields far beyond those of spin glasses (such as in optimization problems, biology, and the study of complexity in many other systems). Thus far, there still exists severe disagreement among the various leading contending theoretical pictures for the understanding of the low-temperature physics of spin glasses. There are, furthermore, no efficient algorithms that allow extended ground state calculations of large systems. We believe that there is an inextricable connection between the low-temperature structure of spin glasses and the optimization algorithms for finding the ground state. I will aim to shed light on and outline various aspects of such a connection. In particular, I will review our work in trying to demonstrate how this connection affords insight into the behavior of spin glasses and optimization algorithms that probe their low-energy states
Land of Limited Opportunities: Disillusionment and Striving for Autonomy Among Refugees and Asylum Seekers in a Madrid NGO
No full textToday there are more displaced people in the world than ever before. While the majority remain internally displaced or settle in neighboring countries in the Global South, a smaller number make it to host countries in the Global North, either as resettled refugees or asylum seekers. The reception and integration of such individuals has become a pressing concern for many Western nations, especially in the face of a marked increase in arrivals, alongside rising xenophobic and anti-immigrant sentiments. The provision of services for this population is often left to humanitarian organizations, which may receive funding to facilitate government reception programs. This dissertation examines the day-to-day operations of one such non-governmental organization (NGO) within Spain, a country that only began experiencing large waves of immigration around the turn of the 21st century, and which has seen a dramatic increase in asylum applications since 2015. Based on ethnographic fieldwork conducted at a refugee and asylum seeker reception NGO in Madrid, this study explores the dynamics of interactions between humanitarian workers and forced migrants as they attempted to carry out the program’s goal of promoting autonomy and integration. In doing so, this research considers the particular challenges humanitarian institutions and professionals faced in implementing the more development-oriented objective of fostering self-sufficiency, and it elucidates how shared precarity and the social class backgrounds of migrants and workers influenced their relationships within the humanitarian space, particularly in the context of an economically challenging local environment. Ultimately, many refugees and asylum seekers came to see Spain as a land of limited opportunities not only for themselves but also for many native Spaniards, as well. As workers strove to assist migrants within these restrictive circumstances, their strategies often failed to further autonomy, instead serving to (re)produce structural inequalities in Spanish society
The Daily Struggle: Philip Guston and American Art in the 1930s
Get PDFAmerican art in the 1930s was shaped by questions of social relevance and utility. The crisis of the Great Depression left millions destitute, and the contradictions of capitalism were exposed for all to see. Many artists and intellectuals, despite their marginal and specialized status in American social life, recognized that there was a need to connect their work to the mass mobilization of the working class, who were organizing in the face of unprecedented poverty and misery. The culture of working-class radicalism in this period, now commonly referred to as the “Red Decade,” was the result of the rapid development of class consciousness and the need to develop strategies of revolutionary praxis to fight oppression, exploitation, and racism. Organizations like the John Reed Club and publications like New Masses acted as sites for the growth of working-class culture, and engaged artists worked to contribute to the revolutionary emancipation of the working class. These social and historical conditions prompted a complex discourse around the responsibility of artists and their relationship with the labor movement, and these questions were made all the more complicated by the creation of the New Deal art programs. Philip Goldstein (later Guston) began his artistic career in this complicated and tense social environment. At the time of the stock market crash in 1929, Guston was only 17, the son of working-class immigrants from Ukraine. He was already a precocious artist, and the crisis of the Depression brought him in contact with the rapidly developing culture of the working class. He encountered a wide range of artistic and intellectual interlocutors at a very young age in Los Angeles. He participated in the John Reed Club, working collectively with other young artists to contribute to the labor movement. His personal interest in Quattrocento Renaissance fresco painting coincided with a broader interest in the possibilities of public mural painting, inspired by the example of Mexican public muralism. He spent the decade seeking opportunities to create public artwork while advancing through his own individual artistic and political development. In 1936, he moved to New York, and eventually secured employment through the New Deal art programs. Through these programs, he completed public mural commissions in New York, Georgia, New Hampshire, and Washington D.C. His experiences as a government artist, which gave him the opportunity to maintain an artistic practice without having to get another job, were formative for Guston, and allowed him to establish an artistic career. He then went on to have a long career as a celebrated member of the New York School, cementing his place in American art history. In this dissertation, I undertake an extended and wide-ranging analysis of both Guston’s early career and the social world of American painting in the 1930s. Guston’s status within the history of American art has grown in recent years; his work is increasingly seen as a unique and vital example within the canon of 20th century American painting. However, this characterization of Guston has emerged in spite of the lack of engagement with his early work. His explicitly political work has been explained away as simple juvenilia, a “product of the times” that is an exception to his otherwise important work as a high modernist. Ellen Landau, in her analysis of Guston’s early work, points out this discrepancy in scholarship on Guston, arguing that the extent of the importance of left-wing politics in Guston’s artistic education “has yet to be acknowledged.” In this project, I take her claim as a call to action, and argue that Guston’s development as a painter in the 1930s, shaped by the massive historical and social forces of period, is crucially important to our understanding of both his work as an individual and of the social role of art in twentieth century American culture
The Morphology, Spatial Distribution, and Collapse Mechanisms of Volcanoes on Venus
Get PDFRadar imagery collected by NASA’s Magellan spacecraft enabled the recognition and classification of volcanic features and structures across Venus far beyond the scope of earlier missions. These datasets revealed volcanoes that range in size from \u3c5 km to well over 100 km in diameter. Volcanism is clearly a major, widespread process on Venus, and is a principle expression of the planet’s secular loss of interior heat. For my doctoral work, I utilized ESRI’s ArcMap and ArcGIS Pro to develop a detailed global catalog of volcanoes across Venus to improve our understanding of the morphology, spatial, distribution, and evolution of volcanism on the second planet. Chapter 2 introduces the creation and implementation of my global catalog of volcanoes and volcanic fields on Venus. This new global dataset includes ∼85,000 edifices, ∼99% of which are \u3c5 km in diameter and are geographically widespread across the entire planet. With this catalog, I developed an automated approach to delineating volcanic fields—high spatial concentrations of small volcanoes—and also noted a dearth of volcanoes 20–100 km in diameter, which could be related to the eruption rate and/or availability of the underlying magma supply. Chapter 3 focuses on a unique subset of 162 volcanoes on Venus that appear to have undergone gravitational deformation. These deformed edifices are distributed globally, are situated at a range of elevations, are spatially proximal to a variety of tectonic structures, and are associated with various crustal thickness values, which together suggest that there are numerous drivers of volcano deformation on Venus. Furthermore, I note examples of flank terraces on Tepev Mons, a structural indicator of volcano sagging that has not yet been documented on Venus. Lastly, Chapter 4 employs kernel density estimation as a tool at nine topographic rises, and nine volcanic fields across Venus to delineate regions where future volcano formation could occur, based on the locations of edifices ≤20 km in diameter from our global catalog developed in Chapter 2. These resulting volcano-formation probability maps reveal that the intensity of volcanism producing volcanoes ≤20 km in diameter in the Beta-Atla-Themis (BAT) region, an area well-known for its enhanced volcanism (Airey et al., 2017), is lower than at topographic rises across the rest of the planet. These maps can also be used to identify specific regions across Venus that future missions such as EnVision and VERITAS can image using their higher-resolution radars and thus search for newly formed volcanoes between the time of those missions and when the Venus surface was originally mapped by Magellan. Based on my analysis, I conclude that these missions should target specific regions of high-volcano-spatial density in and around Atla, Imdr, Themis, and Dione Regiones
Perceived Emotion Regulation Success and Emotion Regulation Motive Satisfaction in Daily Life: Assessment, and Nomothetic and Idiographic Associations with Situations and Strategy Use
No full textBeing able to effectively regulate one’s emotions is important to maintaining well-being. However, when it comes to studying how people successfully regulate their emotions in everyday life, past research has either focused on whether people use emotion regulation (ER) strategies deemed effective based on laboratory evidence or whether strategy use is associated with maximizing positive affect and minimizing negative affect. Aim 1 was to closely capture ER success defined as achieving one’s idiosyncratic ER goals through measuring perceived ER success and motive satisfaction as well as assessing their validity. For Aim 2, we used these novel indicators to test whether strategies show varying levels of average ER success, and whether ER strategies are used more successfully if they fit the situational demands. For Aim 3, we tested whether idiographic patterns emerge in which strategies individuals implement successfully in daily life and whether using a diverse range of strategies successfully is associated with well-being. In a sample of N = 215 undergraduate students, we show that, as predicted, perceived ER success is distinct from positive and negative affect, and perceived success and motive satisfaction are associated with higher well-being as well as trait ER beliefs and ability. We also found that some ER strategies are associated with higher success (e.g., positive reappraisal, acceptance, savoring) but largely failed to show support for specific strategy-situation pairings in which higher success is experienced. Lastly, N=1 idiographic models revealed that people differed widely in which strategies they used successfully. Overall, this study highlights the value of assessing ER success as separate from positive and negative affect in daily life situations due to the diverse ER goals people pursue in daily life and underscores the potential of more person-specific approaches in understanding effective ER