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Essays on Investigating the Revelation of Information Content
No full textThis dissertation consists of three essays on corporate finance.
The first essay studies the differential information content on a firm’s fundamentals of top
executives’ insider trades. It is well understood that a CEO and a CFO have played very
different roles in achieving the goal of a firm. A CEO manages a firm largely from a strategic
perspective, while a CFO focuses more on the tactical aspect. However, it is very difficult to
assess their economic contributions separately because we only observe their joint action and
overall firm performance on the firm level. As a novel approach, we analysis their insider
trading activities and the firm’s following fundamentals changes in this study to understand
their different roles in affecting the firm as a nature experiment. Our results suggests that a
CEO have large impact on a firm’s long term persistent performance while a CFO affects the
firm’s short-term cyclical performance. Moreover CEOs also tend to be more conservative in
investment after additional purchase. This finding is consistent with the fact that they have
different responsibilities in managing the firm.
The second essay, included in Chapter 2, also deals with the topic of information content on
executives’ insider trading activities. Instead of concentrating on purchases, we study whether
the executive’s insider sales also reflect firm’s fundenmentals and compare the information
content contained in CEOs’ and CFOs’ trades. This study highlights the nuanced differences
in trading behaviors between CEOs and CFOs and underscores the importance of sales trades
as indicators of future firm events and the firm’s fundamentals. These insights contribute
to the broader understanding of insider trading dynamics and their implications for market
efficiency.
The third essay, included in Chapter 3, is ”The Real Effects of Cybersecurity Breaches on
Firms and Managers’ Attentiveness”. This study explores the adverse impact of information
breaches and the impact of managers’ attentiveness, measured by the time managers need to
identify the breaches. We find that the time lag from when the breach is identified to when
the announcement is made affects the market reaction and the firm’s operating performance.
The time lag has a quadratic relationship with the cumulative abnormal return in the short
term and with earnings in the long term. Also, the firms tend to react quickly to security
breaches (14.5 days early) when they have a technical-related chief officer
Millimeterwave Beamforming Antenna Arrays and Energy Harvesting Systems for the Next-generation of Sensing and Communication Applications
No full textThe rising demand and dependence on bandwidth-intensive wireless devices have led to a
global effort to create a mobile connectivity strategy that integrates satellites and high-altitude
drone-to-drone (D2D) platforms. Central to this initiative is the need for a highly efficient
antenna design that provides high gain, broadband operation, and high radiation efficiency
with a focused beam along the line of sight. This design also needs to be cost-effective for
mass production to serve a broad market. Despite recent advancements in antenna arrays
for high-frequency applications, few designs have optimized parameters for high gain, broad
bandwidth, and beam steerability. In addition, an antenna array for various vertically stacked
and linear configurations suitable for drone deployment is indeed required. There is a notable
research gap in designing millimeter-wave (mmWave) antenna arrays that are compact (less
than 3λ × 3λ) and broad bandwidth (greater than 50% fractional bandwidth).
Part 1 of this research focuses on designing optimal mmWave antenna arrays, specifically
Vivaldi antennas, to achieve high gain and broadband operation with at least 50% fractional
bandwidth. This helps mitigate the losses caused by atmospheric attenuations at mmWave
frequencies. Antenna array analysis for various vertically stacked and linear configurations
and implementation of active frontend based electronic beam steering is also included within
this portion.
Part 2 of the study explores bias-free energy harvesting techniques using Reverse Electrowetting on Dielectric (REWOD). This method involves using electrolyte impingement through
mechanical modulation for energy harvesting. Traditional REWOD research has used inflexible planar electrodes that require a high voltage bias for better power output. This study
introduces a novel approach using flexible electrodes made with sputtering-based physical
vapor deposition (PVD) on polyimide sheets. Flexible electrodes are essential to overcome
the limitations of traditional planar configurations. This flexible design for REWOD-based
energy harvesting opens up new possibilities for wearable, self-powered motion sensors by
effectively capturing energy from electrolyte impingement.
In summary, the research outcomes include novel mmWave Vivaldi antenna and corresponding
array design with a focus on active beamforming for D2D and military communication
applications, and advancements in bias-free energy harvesting using high-dielectric flexible
electrodes with the REWOD phenomenon. These two contributions of this dissertation
primarily pave a path towards advanced sensing and communication applications
Essays on the Impact of Social Influence on Consumers’ Behavior
No full textThe internet and online platforms have expanded the range of products accessible to consumers,
yet searching and evaluating all options is costly. Online intermediaries often utilize product
popularity and diverse assortments to display products to consumers. Constructing relevant
assortments and rankings requires understanding their causal effect on consumer search
behavior. I apply structural and econometric methods to study the effect of social influence
and different assortments on consumers’ search behavior and judgment in three chapters by
utilizing a publicly available dataset from a field experiment conducted on an online music
platform.
In the first essay, I contribute to the literature on the structural modeling of online consumer
search by (i) separately identifying product position and social influence effects and (ii) allow-
ing consumers to purchase multiple items in each search session. I investigate how consumers’
search behavior changes under different counterfactuals regarding product assortment design
and social information disclosure, and I provide managerial implications for intermediaries to
improve their benefits and revenues. My results show that by revealing product popularity
and sorting items accordingly, platforms can help customers locate and select products more
efficiently, resulting in reduced search efforts but more purchases. Conversely, sorting products
randomly and disclosing their popularity leads to the highest search activity by customers.
In the second essay, I develop an individual-level dynamic model to investigate the herding
behavior of participants by interacting their observational learning with experiential learning.
I find significant evidence of rational herding among participants. The majority of participants,
instead of passively herding their peers (i.e., irrational herding), actively update their belief
and sampling behavior based on the popularity of the songs and the experiential feedback
they receive (i.e., ”rational herding”). If they like popular songs, they would rationally
assume that their taste aligns with that of the crowd and that they are more likely to find
better matches among the popular ones by herding. Conversely, if they dislike a popular song,
they assume that the crowd’s taste is different from theirs and that less popular songs may
be more likely to match their taste. I also find significant heterogeneity in rational herding;
younger participants, females, and experts are more likely to engage in rational herding.
In the third essay, I investigate the effect of social influence(displaying products’ popularity)
on consumers’ perception of product qualities and its consequences on market outcomes. I
find an asymmetric effect of social influence on product ratings based on their intrinsic quality.
High-quality products suffer in ratings in the presence of social influence, while low-quality
ones receive higher ratings. I further investigate the reason for this phenomenon. I show
that due to social influence and its informative role, higher quality products are sampled
earlier, and due to higher expectations and reference points, participants rate them harsher
compared to situations where they have sampled a low-quality product and have a lower
anchor and reference point for the quality
Characterizing and Enhancing Auditory Processing in Rat Models of Autism
No full textCommunication and language deficits are often observed in individuals with autism spectrum
disorder (ASD). Abnormal neural activity patterns impact their ability to understand and produce
language effectively. These impairments arise from delayed and weak cortical responses to
sounds and are pronounced in ASD children with severe language impairments. This dissertation
explores auditory responses from two different rat models of ASD to further understand the
mechanisms behind this deficit and to assess a novel method of intervention.
In utero VPA exposure increases the risk of ASD in children and leads to language impairments.
Rodents prenatally exposed to VPA exhibit similar behavioral impairments, including deficits in
speech sound discrimination. Like ASD children, the auditory cortex of these rodents responds
abnormally, and subcortical regions such as the inferior colliculus (IC) show disrupted
morphology compared to control rats. To determine whether these maladaptive changes occur in
earlier auditory processing areas, IC responses to various auditory stimuli were observed in
VPA-exposed rats through in vivo electrophysiology. VPA-exposed rats displayed significantly
impaired responses to speech sounds, but not to tones and noise burst trains. This indicates that
VPA exposure significantly alters complex sound processing in the IC. Given the degraded
physiology of the IC in VPA-exposed rats, methods to reverse the maladaptive plasticity were
investigated using vagus nerve stimulation (VNS). Two groups of VPA-exposed rats underwent
20 days of either VNS paired with the speech sound “dad” or VNS paired with tones consisting
of various frequencies and intensities. VNS-tone pairing partially restored IC responses in these
VPA-exposed rats, suggesting that VNS-tone pairing can improve auditory processing and
provide a foundation for future research to further investigate the potential for VNS-sound
pairing.
Rett syndrome (RTT) results from a mutation in the X-linked Mecp2 gene, and manifests in
ASD-like behavior such as impaired motor, cognitive, and speech-language skills. Individuals
with RTT typically develop normally until regression symptoms appear at 6 to 18 months.
Similar regression patterns become apparent in Mecp2-deficient rodent models of RTT after 4
months of normal development. Studies have shown that heterozygous Mecp2 rats perform
poorly on auditory discrimination tasks and displayed disrupted cortical activity in the primary
auditory cortex (A1). Most of these findings have been documented in rats that were post-
regression, however, little is known about auditory processing in pre-regression Mecp2 rats.
Therefore, the goal for this genetically influenced ASD model of rats is to document multi-unit
primary auditory cortex responses in pre-regression heterozygous Mecp2 rats. Results
demonstrated that pre-regression rats showed similar degraded auditory responses as post-
regression Mecp2 rats. These findings build upon the contradictory studies that have reported
abnormal behavior in RTT individuals from the pre-regression stage, offering a new perspective
that may lay the groundwork for future research on earlier interventions to benefit heterozygous
Mecp2 rats. In all, these studies provide further evidence of auditory processing deficits in rat
models of ASD and demonstrates that VNS can restore these impairments. Further research into
efficacy and limitations of VNS therapy across other ASD symptoms would be beneficial
Fabrication of Metallic Nanowires by Rotary Jet Spinning
No full textNanowires are the future of the semiconductor and electronics industry as they have ideal
properties in comparison to their size. However, current manufacturing methods of nanowires do
not exploit all the potential that nanowires have. For example, many of these manufacturing
methods are only suitable for a few materials such as gold and silver, but they neglect other
metals such as titanium. Rotary Jet Spinning is a manufacturing method typically used to
produce polymer nanofibers through using centripetal force that extrudes a jet of melted polymer
at a high velocity while it rapidly cools to room temperature. This process relies heavily on
surface tension and viscosity. The higher the viscosity and lower the surface tension, the more
fibers will be formed. To utilize the Rotary Jet Spinning process with metal, a Bismuth-Lead
alloy was mixed with sucrose and poured into a commercial cotton candy machine. The ratio of
sucrose to metal was varied per experiment as well as the size of the shavings of metal. Through
these experiments, it was determined that a weight ratio of 50% metal and 50% sucrose was ideal
to producing the most wires. Additionally, the 6 mm shavings produced significantly less wires
than the other experiments. Nanowires were produced using this method, but further research is
required to optimize all the process parameters
Fictional Geography: Space and Place in Four Novels by Jane Austen, Emily Brontë, Joseph Conrad, and Ahmed Ali
No full textIn this dissertation, I examine four novels by Austen, Brontë, Conrad, and Ali to demonstrate
how each author employs distinctive representations of space and place to portray their
characters’ problematic relationships with gender and race, class, exile, displacement, nostalgia,
and exploitation. By utilizing concepts of space and place as defined by twentieth-century critical
geographical theories and concepts, including cultural, political, existential, and humanistic
geography, we can see how these authors’ purposeful uses of space and place go beyond those of
traditional literary settings. In complex ways, their narratives deploy space and place as key live
figures that shape and determine social norms, cultural clashes, power dynamics, and the
political and economic landscapes inhabited by individuals and societies.
The four novels examined here span over one hundred years of British and Anglophone literature
and history. At the beginning of the nineteenth century, in Pride and Prejudice, Jane Austen acts
as a cultural geographer to observe and represent how her characters’ lives and personalities are
shaped by their interaction with ballroom spaces. In Wuthering Heights, Emily Brontë uses
geography to reveal how the spatial dynamics of a location, atmosphere, landscape, and
wilderness influence the development and destinies of her characters. Her inclusion of the
“other” from a different geographical place is not intended to function as a mere outside cultural
threat (as critics have typically claimed), but rather as a strategy to demonstrate the complex
stakes and ambiguous repercussions of adaptation and survival. Later, in Heart of Darkness,
Joseph Conrad’s descriptions of Congo geography reveal moral and ethical ambiguities
regarding Europeans’ curse-like presence and placelessness in the wilderness of the Congo. At
the beginning of the twentieth-century in Twilight in Delhi, rather than depicting the decline of a
nation (as many literary scholars have claimed), Ahmed Ali employs geography to narrate a
story about the re-birth of a nation whose rich cultural legacy retains the ability to reclaim its lost
sense of place.
Reading these works through the lens of geography enables literary scholars to identify how
authors’ use of space and place charts not only the physical situations of their characters but
explicates how characters’ places are inextricably linked to their emotional and mental
development and decline. This approach allows us to engage with the texts’ spatiality by
imagining and mapping the literary world that authors create culturally and historically, or
metaphorically and symbolically, which provides a deeper understanding of how a specific place
functions at a specific period of time.
My interdisciplinary approach is informed by the work of humanistic and cultural geographers,
philosophers, and literary critics such as Edward Relph, Yi-Fu Tuan, Doreen Massey, Henry
Lefebvre, Michel Foucault, Mikhail Bakhtin, and Edward Said. I focus my analysis on the
intersection of narratology and the spatial turn through close reading of texts and accounts of
authors’ life experiences in the context of recent space and place theories. By considering the
interconnected productivities of space, place, and narrative in these four test cases, I reconfigure
their interpretations within larger frameworks of physical, political, cultural and economic
geographies. Thus, the interplay between literature and geography in this project results in fresh
insights into individual literary works that illuminate their proto-modern dimensions to suggest
unexpected continuities within twentieth- and twenty-first-century global concerns of human
understanding and co-existence
MaskARade : Exploring Hidden Emotions in Portraiture
No full textThis thesis discusses my MFA final exhibition, which combines painting, animation, and
augmented reality (AR) as primary mediums to explore hidden emotions. As a participatory
portraiture project, maskARade explores the masks we often wear to hide our emotions from
others because of societal expectations. The support surface used to output the digital painting is
1/16" aluminum sheet, which serves as a metaphor for the strong exterior we often project to
others and our tendency to mirror the qualities we see in others. Through animation and AR, the
viewer gets a glimpse of the real emotions locked behind the façade, helping them recognize the
emotions in others while challenging them to reflect upon their own emotions and perceptions
Tracing Landscape Dismemberment Through Time: Mapping Sinkholes as Symptoms of Slow Violence Against Landscape Assemblages in Mexico City and New Orleans
No full textThe shocking and unpredictable phenomenon of urban sinkholes is often considered a natural
disaster. Gaping holes crack open without warning, capable of swallowing buildings, cars, roads,
and even people. In this dissertation, I argue that human-induced sinkholes which open in urban
hardscapes emerge, not as natural disasters, but rather as traumatic symptoms of landscapes
experiencing slow violence. Whereas trauma studies have tended to focus on individual or
collective human experiences, I attend to the spatial turn in the field to argue that the missing
part of the discussion remains the tie between historical trauma, urban infrastructure, and
degraded ecosystems. I consider two sinkhole sites as case studies—a thirty-foot-wide fracture in
the cityscape of Mexico City that opened in 2017 and a fissure that opened along I-10 in New
Orleans in 2022. In conversation with scholars in the environmental humanities, this approach
stresses the entanglement of life forms, which, following Anna Tsing, I refer to as landscape
assemblages. In each case, I show that the existence of human-induced sinkholes results from
landscape dismemberment. I define dismemberment as the forced and sustained separation of
key elements of landscape assemblages. My work, both scholarly and artistic, reveals the
palimpsest nature of landscape assemblages where traces of earlier assemblages remain encoded
into the contemporary landscape. To see the relationship between the development of a sinkhole
and human actions on the landscape assemblage I employ counter-cartography mapping
practices to analyze, interrogate, and uncover alternative sightlines through the physical
landscape and in time so that the viewer can see changes happening over hundreds of years while
also holding the moment the sinkhole opened within the same frame. By centering the landscape
assemblage at each sinkhole site and considering shifts within those assemblages as a form of
communication this dissertation hopes to advance the goals articulated by scholars in the
environmental humanities who seek to reorientate the human within the environment, and the
more-than-human within the cultural domain
Nucleobase Isotope Editing as a Versatile Method to Measure the Solution State Stability and Structure of Individual Elements in DNA Duplexes
No full textThe energetic interactions between DNA base pairs are important for processes essential to life,
including DNA replication, transcription, and DNA mismatch repair. The study of structures and
energetics of nucleic acids in solution states is of intense interest to many fields. Due to
experimental challenges associated with the measurement of these critical, atomic scale
interactions, new methods to probe the individual components of energetic interactions are
needed, as accurate measurements under a given set of conditions provide physical insights on
how biological systems functions. Therefore, determining the strength of noncovalent
interactions in DNA duplexes, predicting the stability of DNA duplexes at a specific
temperature, and defining which conformations of the DNA nucleobases exist in solution in the
context of the duplex structure are crucial for understanding how these physical building blocks
accomplish their essential cellular functions.
Experimental methods to determine the individual enthalpic values (ΔHf ) of noncovalent
interactions contained in nucleic acid structural motifs such as the canonical base pair hydrogen
bonds and transition temperatures for individual base pair melting events in DNA duplexes are
lacking despite intense interest in these thermodynamic parameters. Vibrational spectroscopy is a
molecularly resolved detection method, and bands can be sensitive to both conformation and the
atomic-scale chemical environment of specific functional groups contained within the structure.
As nucleic acids are polyatomic molecules that contain multiple normal modes, spectral
congestion can render identifying the frequency of a single mode of interest in the congested,
composite molecular spectrum challenging. This challenge can be overcome by site specifically
incorporating isotopes into various atomic positions in the structure and calculating a difference
spectrum taken between the light and the heavy duplex spectra to extract the signal of interest out
of the infrared (IR) spectrum. Once a bond’s stretching frequency is identified, changes in its
signal can be deployed to determine the structure of local base pairs, and to extract the sub-
molecular-scale, local contributions of a particular structural motif to a duplex’s total stability.
This dissertation focuses on how a specific group of atoms within nucleic acids can be sensitive
probes to measure ΔHf of a single hydrogen bond (H-bond), to determine local melting transition
events, and to reveal local structural components in nucleic acid duplexes. These results amply
demonstrate how the thymine (T) C2=O can be used as an IR probe to measure the local
energetics of a base within a duplex structure. TC2=O can also serve as an IR “sub-molecular-
scale thermometer” to measure location-dependent melting events in a DNA duplex.
Furthermore, these methods can be used to gain new physical insights into rare tautomer
formation in Watson-Crick base pairs, which is proposed to lead to spontaneous mutagenesis.
Resonance-assisted hydrogen bonding (RAHB) of the DNA base pairs have been of interest, as a
potential of rare tautomer formation in WC base pairs may lead to possible spontaneous
mutagenesis. Evidence for RAHB within an A-T base pair in a DNA duplex is reported, with
further physical evidence provided by hydrogen-deuterium exchange experiments and mutation
experiments
Outrider Witness—a Literary Pageant Featuring Hippie Modernist Mischief and Sad Songs of America
No full textOutrider Witness is a verbal collage in which I present a collection of my own
creative writing in the form of poems and anecdotes alternating with analytical
commentary about those works and about their context in the multiple personal
and regional socio-political histories which they reflect. Through this process, I
present niche cultural dynamics of groups with an emphasis on interpersonal and
political power dynamics. In both the creative writing and in my commentary, I
merge trans-periodized literary influences with discursive formats of more ancient
writers. These sources include investigative poetics, Beat, and contemplative
traditions repurposed as contemporary literary trends. I stylize experiential
observations, research, and anecdotal oral interviews into micro essays, breath
meter and subconscious free-associative descriptions of work of art (ekphrasis).
Each chapter includes an additional Artist Statement on my process, influences
and overall observations