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Beyond Recruitment: An Evaluation of the GradFIT Program
No full textThe purpose of this study was to conduct a program evaluation to identify graduatestudent outcomes regarding student self-efficacy and post-secondary completion for a
university’s GradFIT program. The boot camp program focuses on increasing students’
self-efficacy in graduate education preparedness. Quantitative research methodology will
guide the focus of this study. As such, a quantitative approach was used to evaluate the
program’s fidelity, including content analysis, t-tests, and binomial regression. This
research was a summative program evaluation using the logic model as the evaluation
method. Key findings revealed that the program achieves its short-term goals of
increasing students’ confidence and understanding of graduate education, however, most
predictors (ethnicity, gender, GPA, and total efficacy scores) did not significantly
influence graduate school enrollment. The discussion and recommendations are noted,
along with suggestions for future research
Terrain-Aware Robust Control for Quadruped Robots
No full textIn recent years, quadruped robots have captured imagination of both the public and researchers alike. Their capability of traversing uneven terrains surpass their wheeled counterparts. Utilizing this capability of a quadrupedal robot necessitates locomotion frameworks that balance agility, robustness, and adaptability under uncertainty. This thesis presents a unified framework for context-driven locomotion intelligence in torque-controlled quadrupeds, emphasizing minimal reliance on external sensing while leveraging structure in physical interaction. At the core of the framework is a ground contact force-centric predictive control pipeline that fuses coarse terrain priors with proprioceptive feedback to anticipate contact opportunities, along with the ability to react to disturbances post hoc. To support this, we introduce a scalable model abstraction that bridges rigid-body dynamics with contact force estimation, enabling predictive control of body posture and ground reaction forces without full terrain observability. A second layer of the architecture incorporates a low-dimensional gait manifold, learned through structured exploration, which enables efficient switching between dynamic gait models based on terrain features and task constraints which are learnt offline prior to deployment. Finally, we introduce a cross-domain transfer strategy that fine-tunes control parameters learned in simulation using a physics-aware adaptation policy, reducing the sim-to-real gap without manual retuning. We validate our methods on both simulated and physical quadruped platform Unitree A1. Experimental results show improved robustness in locomotion across discontinuous, and partially observable terrain, while maintaining control efficiency and stability
The relation between YAP/TAZ expression and cell proliferation inH295RM cells in determining the driving force in L205R caused Adrenal Cushing’s Syndrome
No full textSRC Head Movement Analysis During a Graded Exercise Test
No full textSport-related concussions (SRCs) can disrupt vestibular and neuromotor function, yet clinical assessments often fail to capture subtle deficits that persist after symptom resolution. This study evaluated changes in angular head acceleration during the Buffalo Concussion Treadmill Test (BCTT) at two time points: within 72 hours of an SRC and once participants were symptom-free (SF). Eleven NCAA Division I athletes completed motion capture-based assessments while undergoing graded exertion. Head acceleration was measured in the roll (X), pitch (Y), and yaw (Z) planes. Data were analyzed using non-parametric tests and repeated measures ANOVAs to assess differences and changes in acceleration over time.Although few group-level differences reached statistical significance, moderate to large effect sizes were observed, particularly in the pitch and roll planes, suggesting that vestibular or neuromotor deficits may persist even after clinical recovery. Acceleration patterns in the SRC condition demonstrated progressive increases under exertion, while the SF condition remained relatively stable. These findings suggest that angular head acceleration may serve as a sensitive marker of post-concussive dysfunction not captured by traditional tools such as the SCAT6.
This study supports integrating motion analysis with exertional testing to enhance clinical return-to-play (RTP) decisions. Future research should include larger samples, physiological markers (e.g., heart rate, RPE), and advanced motion capture techniques to improve the sensitivity and utility of dynamic vestibular assessment in SRC management
Amperometric Characterization of Nanosecond Electric Pulse-Evoked Exocytosis in Adrenal Chromaffin Cells: Custom Experimental Setup and Spike Detection Software
No full textNanosecond electric pulses (NEPs) have emerged as a promising tool for modulating neurosecretion by bypassing traditional receptor-mediated pathways. This dissertation
explores the use of a single 5 ns, 7–9 MV/m pulse to stimulate catecholamine release from
isolated bovine adrenal chromaffin cells, a well-established model for studying Ca2+
regulated exocytosis. While previous studies using Ca2+ imaging and total internal
reflection fluorescence microscopy (TIRFM) have demonstrated NEP-induced increases
in intracellular calcium concentration ([Ca²⁺]i) and associated exocytotic activity, the goal
of this work was to directly quantify individual granule fusion events in real time using
carbon fiber amperometry and to characterize the kinetic and temporal features of the NEP-evoked amperometric responses.
A major technical challenge in implementing amperometry with high intensity NEP
stimulation is protecting the highly sensitive amplifier circuitry from high-voltage damage
while minimizing the interruption in data acquisition. To address this issue, a customized
switching system was developed using a combination of reed relays and semiconductor
switches controlled by LabVIEW and a National Instruments data acquisition card. This
setup enabled brief disconnection of the carbon fiber electrode (CFE) from the amplifier
during NEP delivery, achieving a data recording gap of less than 5 ms without distorting
either the NEP waveform or amperometric data. This switching platform provides a
broadly applicable solution for studies requiring electrical isolation during stimulation.
To analyze the resulting amperometric data, a custom MATLAB-based tool (ASAT) was
developed for spike detection and quantification. Unlike conventional datasets, NEP stimulated recordings include electrical artifacts that can obscure early spike activity. ASAT was designed to address this challenge by incorporating flexible filtering options, artifact-exclusion regions, and a manual spike review interface to ensure accurate event
detection. The tool extracts key parameters such as spike amplitude, half-width, charge,
and estimated number of molecules released, enabling a detailed characterization of
granule fusion kinetics.
Amperometric recordings revealed that NEP-evoked spikes were comparable to DMPPevoked events in quantal size and kinetic features. However, a notable distinction was the
presence of a delay in the onset of exocytosis following NEP stimulation in a majority of
cells, ranging from 1 to 5 seconds, despite a rapid rise in [Ca²⁺]i. In contrast, DMPP-evoked
exocytosis occurs immediately, suggesting that downstream fusion mechanisms may be
differentially regulated following NEP exposure.
Simultaneous Ca²⁺ imaging and amperometry in cells loaded with the fluorescent Ca²⁺
indicator Calcium Green -1 confirmed that [Ca²⁺]i increased immediately after both stimuli,
but only NEP-exposed cells showed delayed secretion. Additional analyses revealed that
Ca²⁺ response profiles (short-lived vs. long-lived) were reflected in the response pattern of
catecholamine release, with sustained Ca²⁺ elevations supporting prolonged exocytotic
activity. The presence of Calcium Green-1 dye did not significantly alter spike parameters,
validating the dual-mode imaging approach.
These findings represent the first real-time quantification of exocytosis triggered by a
single 5 ns pulse Overall, this work lays a strong technical and analytical foundation for
investigating NEP-induced exocytosis. It also opens the door to future studies aimed at
uncovering the molecular mechanisms behind NEP-specific effects on exocytosis
Primary and Secondary Mineral Analysis of Three Hawaiian Hydrothermally Altered Drill Cores as an Analog for Subsurface Aqueous Processes on Mars
No full textThe Martian surface is predominantly basaltic, with extensive shield volcanoes formed over mantle hotspots. Evidence of water at and below the surface manifests in widespread detection of aqueous alteration of these basalts, with minerals ranging from phyllosilicates, sulfates, and carbonates. These detections are particularly noted in Noachian-aged terrains – which are considered the oldest, and lower lithological units. The presence of Al-phyllosilicates, Fe/Mg smectites, sulfates, and carbonates in stratigraphic sequences suggests multiple formation pathways, including in situ weathering, alteration of volcanic ash, or hydrothermal activity driven by volcanism or impact cratering. To accurately interpret these alteration signatures on Mars, it is crucial to establish well-characterized basaltic alteration sequences on Earth. Hawaiian basalts, formed in an oceanic hotspot setting, provide an ideal terrestrial analog for altered basaltic terrains on Mars.This study utilizes samples from three continuously cored deep subsurface exploration wells in Hawai‘i to investigate hydrothermal alteration in blind low to high temperature aqueous systems. These wells include: (1) PTA-2, a groundwater turned geothermal exploration well at the Pōhakuloa Training Area on the Island of Hawai‘i; (2) KMA-1, a groundwater exploration well at the Keāmuku Maneuver Area on the island of Hawai’i; and (3) HPF Well 10, a geothermal exploration well in the Pālāwai Basin on Lāna‘i Island. These wells were initially drilled for groundwater and geothermal assessments, and alteration mineralogy was not a primary focus of those studies. However, understanding alteration mineralogy is critical for constraining subsurface aqueous processes and fluid-rock interactions, which is not well documented outside the Kilauea East Rift Zone.
This dissertation presents a detailed alteration analysis using visible to short-wave and long infrared (VSWIR - LWIR) spectroscopy as the primary characterization tool. Each drill core revealed distinct alteration environments. PTA-2 and HPF Well 10, which had elevated subsurface temperatures, exhibited pervasive smectite group clays and zeolite alteration in vugs, fractures, and veins, with HPF Well 10 also containing abundant carbonate minerals. In contrast, KMA-1, the coolest well, displayed acid-sulfate alteration dominated by jarosite, alunite, and iron oxides.
These findings demonstrate that alteration mineralogy provides key insights into the history of subsurface aqueous alteration activity and can support observed structures controlling fluid flow. Such data can support exploration efforts and improve subsurface characterization in Hawaii. Furthermore, subsurface analog studies remain scarce in planetary science. This research advances our understanding of subsurface alteration processes on Mars by providing a comparative framework for interpreting secondary mineral bearing units in various volcanic settings. The opportunity to analyze drill cores from multiple geological contexts—ranging from a saddle region between two shield volcanoes to a system near a caldera center—further enhances our ability to assess localized hydrothermal alteration and its implications for planetary exploration
Disentangling how climate change and forest management alter fuels and fire regimes in Sierra Nevada forests
No full textExtreme wildfires are increasing in forests around the globe and releasing billions of tons of previously sequestered carbon into the atmosphere every year. In the California Sierra Nevada, wildfires have become more extreme in response to both climate change and historical fire suppression. To address these changes, forest managers use fuel treatments to reduce fire hazard, return fire regimes to their historical range of variability, and promote stable forest carbon. These treatments include a range of mechanical (e.g., thinning, pruning, mastication) and prescribed fire (e.g., broadcast burns, pile burns) approaches. However, it remains unclear how fire regimes will change under future climate—and when, where, and what fuel treatments will be most effective in the face of those changes.Simulation models provide a tool for projecting how climate change will influence future fire regimes, the extent to which shifting fire regimes will release carbon to the atmosphere, and when and where we can mitigate these changes through fuel treatments. Models provide a framework that enables us to replicate and evaluate the factors that influence fire regimes and postfire carbon dynamics across complex landscapes. However, models are subject to a range of uncertainties and limitations that must be quantified and addressed to make reliable predictions about the future. In this research, I developed, evaluated, and applied a set of models to investigate how climate change is altering fire regimes in the Sierra Nevada ecoregion and how we can best mitigate those changes through fuel management.
In chapter 1 of my dissertation, I demonstrated how multiple time series characteristics vary among downscaled Global Climate Model (GCM) projections for four watersheds in the Sierra Nevada Ecoregion, and how each GCM’s time series characteristics vary between watershed and regional scales. Then, using these downscaled GCMs as forcing data for a biophysical, fire regime model, I examined how fire regime projections can vary in response to these temporal and spatial input uncertainties. Finally, I illustrated how these analyses can be used for more robust GCM model selection. Conducting more comprehensive time series analyses enables modelers to more mechanistically link meteorological forcings with biophysical model projections.
In chapter 2, I conducted a factorial modeling experiment to investigate how climate change and prescribed fire influence future fire regimes and carbon retention in a high-elevation, mixed conifer-dominated watershed in the Sierra Nevada Mountains. I found that climate change led to smaller and more frequent fires across the landscape and that fire hazard increased in the most mesic locations of the watershed due to their historically high fuel loads and climate change-driven increases in fuel aridity. Prescribed fire reduced the size of the largest fires, reduced fire hazard in the most mesic locations, and decreased carbon emissions in subsequent wildfires across the watershed. However, in the hottest and driest future climate scenario, climate change-driven increases in fire hazard outstripped decreases generated by prescribed fire. Our findings suggest that alongside other forest management practices, and in accordance with greenhouse gas reductions, prescribed fire can play an important role in managing fire hazard and increasing decadal-scale carbon retention in fire-prone, climate-impacted landscapes.
In chapter 3, I quantified the short- and long-term impacts of fuel treatments on both carbon sequestration and fire risk using the Forest Vegetation Simulator (FVS) at large spatial scales. I develop a cloud-based model framework around FVS to spatialize model outputs of total stand carbon and surface fuels at a 30-m resolution along with their associated uncertainties. As a case study for the new model framework, I simulated nine fuel treatment scenarios for the Tahoe Basin and found that topography plays a key role in long-term carbon outcomes and identified potential underestimation of vegetation density. I then identified how parameterization could be improved to increase confidence in vegetation growth estimates
Sarrionandia’s Literary Exile: The Art of Fugue
No full textThis dissertation, titled “Sarrionandia’s Literary Exile: The Art of Fugue,” investigates the intricate dynamics of literary expression and exile in the works of the renowned Basque author Joseba Sarrionandia. Given the extensive literary oeuvre of the writer, this research delineates the corpus of the period from 2001 to 2010, during which the author resided in his Cuban exile in Havana. From this period, the works selected for analysis are those that have received the most recognition, including Lagun izoztua published in 2001 (The Frozen Friend), Kolosala izango da in 2003 (It Will be Colossal), and Moroak gara behelaino artean? in 2010 (Are We Moors in the Mist?). The main body of the dissertation consists of a literary analysis of the aforementioned works, grounded in theoretical concepts situated at the intersection of exile and literature. The concepts of counterpoint as coined by Edward Said and the dialectic of exile articulated by Sophia A. McClennen play a significant role throughout the research. Other notable conceptual frameworks include the Ovidian and solar paradigms of exile developed by Claudio Guillén, Paul Ilie’s notion of inner exile, Fernando Ortiz’s transculturality, and Aimé Césaire’s theory of the choc en retour of the imperial past
Population Genetic Structure of Ixodes pacificus Ticks and Detection of Their Pathogens In-Silico
No full textTicks are hematophagous ectoparasites responsible for the transmission of several serious illnesses in humans, domestic animals, livestock, and wildlife. As climate changes and ticks are introduced into new areas by their host, regions unfamiliar with tick-borne disease become vulnerable to potential public health crises. The movement and subsequent adaptation to the new environment by ticks can be modeled using genetic information and can be used to inform public health agencies of the risk of encountering ticks. Using Restriction-site DNA sequencing (RAD-seq) (Chapter 2), tick migration, phylogenetic relationships, population structure, clustering patterns, and isolation by distance can be analyzed and allow researchers to predict tick movement and risk for disease. Even further, performance of Genome Wide Association Studies (GWAS) will allow researchers to find genes with significant single-nucleotide polymorphisms (SNPs) and identify traits affected in different populations of ticks. Understanding how ticks are adapting to their environment, or their host associations can assist in developing new and effective tick control strategies. The research detailed in this thesis aims to understand 1) population structure of Ixodes pacificus in the western United States, and 2) a novel method of detecting tick-borne pathogens in-silico. In Chapter 2, we aimed to understand if I. pacificus, the western black-legged tick, has a population structure and if there is genetic differentiation between tick populations. Using Restriction site Associated DNA sequencing (RAD-seq), we identified three main populations of ticks and a pattern which suggests ticks are rapidly expanding into new areas in Oregon and Washington. Additionally, California populations appear to be more established, insinuating that ticks have been moving south to north. This information allows for us to track tick movement and assess tick encounter risk in new, high-risk areas. In Chapter 3, we attempted to utilize HISAT2, a sensitive and rapid genome aligner, to detect tick-borne pathogens computationally (in-silico). Pathogen genomes were aligned to RAD-seq reads to detect pathogen signatures in our samples. HISAT2 successfully detected two tick-borne pathogens, but depending on the species or type of pathogen it could either not distinguish between species or cannot detect their presence accurately. Utilizing a simple bioinformatic tool to test hundreds of samples at a time could speed up the time it takes to diagnosis and treat the pathogen, as well as decrease the need for specialized staff. More work is needed in the future to assess whether using bioinformatic tools to detect and diagnosis tick-borne pathogens and illnesses is a viable route to take in regards to tick-borne disease testing. The following studies are vital in understanding the basic biology, pathogen prevalence, and population dynamics of and in I. pacificus and have given us crucial insight into this tick
Performance Evaluation of One-Dimensional Site Response Analysis: Insights from Physics-based 3D Earthquake Simulations
No full textDespite the complexity of real earthquake ground motions, one-dimensional site response analysis (1D SRA) is the current state of practice for considering the modification of incident seismic waves due to local soil deposits and predicting site-specific ground motions. In this idealized 1D approach, the local soils are assumed to be composed of stacked horizontal layers without lateral heterogeneity, and the horizontal and vertical ground shaking are assumed to be induced by vertically incident shear and compressional waves, respectively. This 1D idealization decouples the horizontal and vertical components of the actual seismic wavefield and greatly simplifies the reconstruction of the input excitation for practical engineering applications. However, recent site response studies have highlighted potentially significant deviation of the 1D predictions to actual recordings from earthquakes. Of particular concern is the estimation of site-specific vertical ground motions for critical infrastructures, where this 1D approach has routinely been observed to predict abnormal vertical site amplifications. These observations have collectively cast new doubts on the validity of this idealized 1D site response procedure for approximating real-world complex seismic wavefields.This doctoral study conducts a comprehensive performance evaluation of 1D SRA when applied to free-field site response prediction and soil-structure interaction (SSI) analysis of civil infrastructures. A simulation-based approach is adopted, and a progressive set of numerical studies based on realistic simulated ground motions from broadband physics-based three-dimensional (3D) earthquake simulations were carried out to gain physical insights into the observed discrepancies. The results of this study show that in actual seismic wavefields, the horizontal and vertical motions are governed by distinct site amplification mechanisms. While the horizontal motion exhibits a dominant shear wave propagation phenomenon, the vertical motion results from a combination of compressional and shear wave propagation. Two deficiencies inherent in this 1D approach, namely, the systematic overprediction of the vertical motion and excessively long-duration motions predicted with the in-column input motion, are identified, and corresponding physical explanations are provided. The vertical motion overprediction is associated with the limitation of the 1D approach in accounting for the refraction of large-amplitude inclined shear waves when propagating through the surficial soft layers. The excessively long-duration motions are caused by the enforced fixed boundary at the base of the 1D soil column that is unable to accommodate the outgoing waves, resulting in wave trapping in the soil column near the site periods. The observed spatial variability in the comparison results and sensitivity studies on the basin profile demonstrate that the accuracy of the 1D procedure is dependent on the wavefield composition of both the 1D input motions and the actual site response. Overall, in the horizontal direction, the free-field site amplification and subsequent dynamic filtering of the base motions within representative structural systems can be reasonably captured by the assumed vertically propagating shear waves. In contrast, vertical free-field seismic motions and structural demands are overpredicted in most cases when using idealized vertically propagating compressional waves. Special attention should be given to the potentially severe in-structure vertical floor accelerations predicted by the 1D approach due to the combined effects of fictitious free-field vertical site amplification and significant vertical dynamic amplification within the structure, as this can pose unrealistic challenges to seismic certification of secondary equipment systems necessary for structural and operational functionality and containment barrier design of critical infrastructures. It is also demonstrated that vertical SSI effects can be more significant than those in the horizontal direction due to the large vertical structural stiffness and should be considered in vertical floor acceleration assessments, especially for massive high-rise structures