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The Effects of General Acute Stress and Attachment Insecurity on Perceptions of Infant Distress
No full textThis study examines caregiver-infant relationships, focusing on how caregivers' general stress levels influence their perceptions of infant distress. Infant cries serve as biological signals for care and support, but stress can hinder a caregiver’s ability to accurately interpret distress cues, potentially affecting their responsiveness. To investigate this, participants from a university campus engaged in a caregiving task using an infant simulator. Their caregiving behaviors, including feeding, diaper changing, and soothing, were observed and recorded. Attachment qualities and self-reported stress measures were also recorded. Findings show that higher levels of general acute stress often impacted perceptions of infant distress; specifically, higher levels of general acute stress were associated to perceptions of the infant simulator as aversive. Higher levels of acute general stress were also associated with higher feelings of frustration and less sympathy towards the infant simulator as well. Attachment Insecurity did not seem to have major significant associations with perceptions of or reactions to infant distress. These findings highlight the importance of supporting caregiver stress management and providing additional resources to families facing stressful circumstances, as a means of promoting healthy infant development and more effective caregiving
Annotated Bibliography Activity - Instructor Version
No full textThis group activity focuses on writing and organizing an annotation paragraph. Students will work in groups to create different parts of one annotated bibliography citation
AI-Driven User Experience and Accessibility Enhancements for a Sensor-Based Platform
No full textThe complexity and volume of IoT-generated data have grown rapidly, outpacing the ability of non-expert users to interpret and act on it to make real-world decisions. This thesis presents a prototype platform that integrates artificial intelligenceto enhance both the user experience and accessibility in data-intensive environments. The system implements a conversational large language model capable of generating real-time, natural language summaries of various types of data visualizations-making complex information more accessible to users, particularly those relying on screen readers or keyboard-only interactions. A comprehensive assessment of the system and data interpretation capabilities demonstrates its reliability and preferred use by users. Beyond data summarization, the portal enables further querying of data, allowing users to converse with AI using natural language to explore insights without needing expert knowledge on the domain. The interface possesses full keyboard accessibility design and a suite of guided help videos to accommodate a wide range of accessibilityneeds. Additionally, a map-based visualization layer was launched, allowing users to explore live sensor data and receive AI-driven insight related to the geographical positions of the sensor. The prototype has been applied to a platform for environmental monitoring, but demonstrates potential across domains such as agriculture, healthcare, financial management, and citizen science
Estimation and Enhancement of Hydrodynamic Performance of Bio-Inspired Underwater Propulsion
No full textFluid-structure interaction (FSI) research plays a pivotal role in the field of biomimeticand bio-inspired underwater propulsion in soft robotics, towards enhancing hydrodynamic
performance, maneuverability, and energy efficiency of underwater vehicles for exploration,
defense, and resource prospecting. In this project, we focus on the study and understanding
of the fundamental physical mechanisms of a novel paradigm of bio-inspired underwater
robotic propulsion based on the transformative concept of active stiffness and shapemorphing.
Our aim is to formalize a comprehensive experimental and computational framework
to shed light on the complex interplay of unsteady fluid flows and dynamically morphing
structures.
Chapter 1 introduces the study of biomimetic propulsion in underwater soft robotics,
where we highlight the approaches used to investigate the relevant FSI modeling. We present
a literature review of the mechanisms that FSI community has intensively studied. Finally,
the goals of the project, thesis outline, and document organization are concisely introduced.
In Chapter 2, we present a comprehensive experimental study on harmonic oscillations
of rigid plates with H-shaped cross sections submerged in stationary fluid environment. We
conduct a detailed experimental investigation of the flow physics created by the presence of
the flanges, that is, the vertical segments in the plate cross section. We perform particle image
velocimetry (PIV) experiments over a broad range of oscillation amplitudes, frequencies, and
flange size to width ratios by leveraging the identification of pathlines, vortex shedding and
dynamics, distinctive hydrodynamic regimes, and steady streaming.
Chapter 3 introduces a new nonlocal hydrodynamic theory for fluid-structure interactions
of cantilever beams and plates undergoing small amplitude vibrations in quiescent, Newtonian,
incompressible, viscous fluids. Our approach is based on a rigorous, yet efficient, 3D
treatment of the hydrodynamic loading on cantilevered thin structures. The off-line solution
of the FSI problem results in the so-called nonlocal modal hydrodynamic function matrix,that is, the representation of the nonlocal hydrodynamic load operator on a basis formed by
the structural modes. Our theory then integrates the nonlocal hydrodynamics within a fully
coupled structural modal model in the frequency domain. We compare and discuss our theory
predictions with the predictions of the classical local approaches, for different actuation
scenarios, identifying the limitations of the existing treatments. For clarity of presentation,
torsional vibrations of cantilever beams are investigated in a separate study, in Chapter 4,
due to technical differences in the treatment of the problem.
Chapter 5 presents an experimental study to investigate the effects of shape-morphing on
the flow physics of an oscillating submerged plate in a quiescent, incompressible, Newtonian
viscous fluid. This is the first soft robotic setup in which we implement and demonstrate
a time varying underwater shape-morphing deformation. With PIV and force measurement
via a load cell, we demonstrate that shape-morphing significantly results in reducing vortex
shedding intensity, minimizing hydrodynamic forces, and lowering energy dissipation.
In Chapter 6, we summarize the completed work on the vibration characteristics of
a plate oscillating in-air and in-vacuo. First, the concept of curvature-based stiffening is
introduced, which serves as a method to arbitrarily tune the stiffness and natural frequencies
of a microplate sensor for atomic force microscope applications. We perform a macroscale
experiment to verify the feasibility of this method. For our project, curvature-based stiffening
provides a preliminary perspective for active shape-morphing. The second part of Chapter 6
discusses the nonlinear vibration behavior of a shape-morphing cantilever plate excited by
base acceleration and time varying shape-morphing deformation. The interplay of these
motions causes the system to demonstrate distinctive and tunable nonlinear behavior. We
present frequency responses based on a finite element parametric study of the actuation
parameters, and propose a minimal modeling of the system based on the Duffing oscillator.
Chapter 7 summarizes this dissertation and my contributions to the project. Finally, the
chapter outlines future work for other researchers in our community
The Impact of the COVID-19 Pandemic on Cancer Patients: From Mortality Patterns to Long-term Sequelae
No full textThe COVID-19 pandemic has constituted one of the most significant public health challenges of this century, profoundly impacting global mortality patterns and healthcare systems. In addition to the immediate consequences of acute infection, a considerable proportion of individuals experience persistent symptoms that extend well beyond the acute phase. Cancer patients are particularly vulnerable to pandemic-related changes, as they are already burdened by chronic illness, immunosuppression, and complex treatment needs. Although previous research has documented an increased risk of severe COVID-19 outcomes among individuals with cancer, there remains a notable lack of population-level studies examining its real-world impact on cancer mortality. Simultaneously, there is an urgent need for large-scale, nationally representative research to evaluate the long-term consequences of COVID-19 among cancer survivors. Furthermore, in modern clinical contexts, the co-occurrence of multiple chronic health conditions—including cancer—has become increasingly common, raising concerns about whether individuals with multimorbidity face elevated risks of developing long COVID.This dissertation aimed to investigate the multifaceted consequences of the COVID-19 pandemic on cancer patients, focusing on changes in mortality patterns and long-term health outcomes:
The first study examined cancer-related mortality changes in the state of Nevada during the first two years of the pandemic (2020–2021), comparing observed deaths to expected values based on pre-pandemic data from 2015 to 2019. The findings showed that overall cancer-related mortality—defined as deaths where cancer was listed as either the underlying or a contributing cause—experienced a modest decline during the pandemic. More specifically, deaths with cancer as the underlying cause declined relative to expectations, while deaths listing cancer as a contributing cause increased. These shifts may be attributed to the mortality shifting from cancer to COVID-19, reduced diagnosis during the pandemic, and potential omissions or misclassification on death certificates.
The second study utilized nationally representative data from the 2022 Behavioral Risk Factor Surveillance System (BRFSS) to assess the prevalence of long COVID among cancer survivors. The results indicated that cancer survivors had significantly higher odds of experiencing long COVID compared to individuals without a cancer history, with the disparity being most pronounced among younger adults. Additionally, the study found that cancer survivors required a higher number of COVID-19 vaccine doses to achieve a significant association with reduced odds of long COVID, compared to those without cancer.
The third study, based on 2023 BRFSS data, explored the relationship between chronic health conditions (CHCs) and long COVID across three dimensions: individual CHCs, cumulative CHC burden, and multimorbidity patterns. All CHCs tested were significantly associated with elevated odds of long COVID. A clear dose-response relationship was observed between the number of CHCs and the odds of long COVID. Furthermore, multimorbidity clusters identified through latent class analysis (LCA) were significantly associated with increased odds of long COVID, with the Severe Multimorbidity Cluster showing the strongest association. In most multimorbidity groups, COVID-19 vaccination was not significantly associated with a reduction in long COVID odds.
Collectively, these studies provide new insights into changes in mortality patterns during the COVID-19 pandemic and the long-term consequences of infection among populations with cancer. The findings highlight the importance of enhancing long-term surveillance, implementing targeted follow-up and supportive care strategies, and promoting COVID-19 vaccination to reduce pandemic-related health disparities in this high-risk population
Decrepitation of Crushed Leach Copper Ore Under Sulfuric Acid Leaching Conditions-Part 2
No full textThis paper was presented at the Heap Leach Solutions Conference, October 19-21, 2025, Sparks, Nevada.Decrepitation of crushed leach copper ore under sulfuric acid leaching conditions refers to the mechanical and geochemical breakdown of the ore. Mechanically, the process of stacking and burying via multiple lifts of ore will break the ore down through time. Geochemically, sulfuric acid solution leaching will break down the ore by reacting with a variety of gangue and ore minerals to generate new minerals. Together, these two processes fundamentally lead to a greater quantity of finer particles, shifting the uniformity of the grain size distribution, reducing the hydraulic conductivity, and potentially leading to the generation of excess pore pressure when sheared, all of which are potential precursors to undrained behavior of ore during loading or shearing. Historically, leached copper ore stockpiles have been assumed to remain freely draining during their lifetimes, mobilizing drained shear strengths. However, decrepitation can create low-permeability, fine-grained layers that force parts of a stockpile to mobilize undrained shear strengths, reducing the overall shear strength or generate the potential for a static liquefaction event. Sulfuric acid leaching on copper ore stockpiles thus necessitates careful management to monitor for evidence of decrepitation potentially leading to low permeability that limits copper recovery as well as a potential reduction of shear strength that may require implementation of stability management practices. A reliable and reproducible methodology to identify and quantify the onset of decrepitation is essential for evaluating its overall impact on a copper ore crushed leach stockpile. Within this paper, we present a methodology based on a study conducted at four existing crushed leach copper stockpiles with various ages under sulfuric acid leaching to investigate the relationship between the cone penetration test (CPT) response, hydraulic conductivity, and laboratory geotechnical properties of crushed leach copper ore. We identify two different and distinct trends for crushed leach copper ore exhibiting drained behavior versus undrained behavior, signalling the onset of decrepitation, and quantify the transition point between these two behaviors with regards to CPT-based criteria, hydraulic conductivity, and laboratory geotechnical properties for which the shear behavior fundamentally changes
Laboratory Chemical Characterization of Fresh and Aged Bioaerosols
No full textBioaerosols are biological aerosol particles in the atmosphere, such as pollen, fungi, algae, and bacteria, with sizes ranging from a few nanometers to hundreds of micrometers. The importance of bioaerosols has been growing due to climate change, however, their chemistry and atmospheric fate are still largely unexplored. The contribution of bioaerosols and their organic compounds to the atmospheric organic carbon load, and their role in cloud physics and atmospheric processes should be studied further. To address this knowledge gap, this dissertation investigates the chemical composition of water-soluble extracts of various types of bioaerosols and the effects of laboratory aging, such as exposure to simulated solar radiation and OH radicals. The bioaerosols chosen for chemical characterization were lodgepole pine pollen, rabbitbrush pollen, western gall rust fungi, hay Bacillus bacteria, Pedobacter bacteria, and Spirulina alga. Using various analytical techniques, such as gas chromatography – mass spectrometry (GC-MS), ultra-high performance liquid chromatography – mass spectrometry (UPLC-MS), ultraviolet-visible-near-infrared spectrophotometry (UV-Vis-NIR), proton nuclear magnetic resonance spectroscopy (1H-NMR), and Fourier-transform infrared spectroscopy (FTIR), organic species (saccharides, amino acids, and fatty acids) and functional groups of these bioaerosols were determined. Chemical analysis showed that the saccharide glucose was common between all analyzed bioaerosol extracts, and the major contribution of organic species in pollen was from saccharides. Laboratory aging was performed on lodgepole pine pollen and Spirulina alga using the Suntest CPS solar simulator. These bioaerosols were exposed to (1) simulated solar radiation, ranging from 300 to 800 nanometers, and (2) OH radicals formed by hydrogen peroxide through photolysis. Functional groups were compared before and after aging using 1H-NMR and FTIR spectroscopy to uncover the chemical transformation and changes in polarity of the bioaerosols. FTIR results showed an overall increase of polar functional groups in the two bioaerosols after aging with simulated solar radiation. Though 1H-NMR showed no significant changes after simulated solar aging, the functional group distribution transformed dramatically after exposure to OH radicals. In summary, this research was instrumental in understanding the contribution of various organic compounds to bioaerosol chemistry and the transformation of bioaerosols after exposure to atmospheric aging
Changes in Gold Heap Leach Fluid Chemistry after 30 Years of Closure
No full textThis paper was presented at the Heap Leach Solutions Conference, October 19-21, 2025, Sparks, Nevada.Since the 1960's mining for gold and silver using heap leach cyanide processes has been a major industry in the western United States. This has proven to be a cost-effective method for processing low-grade gold and silver ore. Following months to years of leaching, the heaps and associated ponds that collect the water are reclaimed. However, it is not well understood how various chemical constituents observed in the heap effluent change as closure is completed and as water is released from these facilities. The water quality of the released effluent is of concern. Even though the flow rates decrease/stabilize over time, the contaminant load in the released water can be high. This contaminant load depends on the extent of rinsing; either by recirculation or by the flow of meteoric water (rain and snow). Over time, as meteoric water rinses the heap, the concentrations of the easily soluble contaminants will decrease. As closure continues, specific constituents, including cyanide and mercury, will decrease. Nitrate concentrations will initially increase and then ultimately rinse out. Alternatively, the more tightly held constituents, particularly arsenic, will take longer to elute, and potentially can increase in concentration, depending on changes in pH or continuing reactions in the heap material which can release arsenic. Understanding how the contaminant load changes over time will assist in proper management of these facilities
Seismic Response of Nonstructural Platform framed Cold-formed Steel Walls Subassemblies Detailed for Drift Compatibility
No full textCold-formes steel platform-framed nonstructural walls are critical to building functionality and often damaged at low drift levels during earthquakes. To investigate this problem, both exterior and interior wall subassemblies were integrated into a full-scale 10-story mass timber building at NHERI@UC San Diego. The walls were constructed with two types of horizontal slip tracks and three types of corner expansion joints to improve their seismic resilience.Experimental results showed that properly detailed slotted and double slip tracks allowed effective wall slip and limited damage. However, variations in slip performance revealed that wall behavior is highly sensitive to construction quality and frictional resistance. To further interpret these findings, analytical modeling was conducted: a detailed finite element model in ANSYS was used to estimate wall stiffness, while a simplified model in OpenSees evaluated slip behavior under different friction levels. Design recommendations were proposed for slip joint friction in nonstructural walls