33760 research outputs found
Sort by
Examining Contributors to Black Maternal Health Experiences in Prince George’s County, MD
No full textBlack women in the United States face a maternal mortality rate three times that of white women, a disparity mirrored in Prince George’s County, Maryland (Hoyert, 2023; Maryland Department of Health, 2022). In 2019, the Prince George’s County Health Department reported that between 2008 and 2017, Black, non-Hispanic mothers experienced the highest pregnancy-related maternal mortality rate (37.4 deaths per 100,000 live births) in the county (“Maternal Infant and Health Report,” 2019). This study explores how maternal access to healthcare and provider cultural competency training influence maternal health disparities in Prince George’s County. Using a mixed-methods approach, the research team surveyed and interviewed two key populations: Black mothers ages 18-34, residing in Prince George’s County, Maryland, and maternal health providers practicing in the District of Columbia, Maryland, and Virginia (DMV) region. By examining patient-provider interactions and gaps in medical education, this research aims to inform policy and curricular reforms to improve Black maternal health outcomes.Gemstone Honors Program, University Library Awards, Launch UMD
LOST TO THE SOUNDS OF THE WORLD FOR CHAMBER ORCHESTRA, SOPRANO, AND ELECTRONICS
No full textInspired by the vivid and poetic writing of American environmentalist Sigurd F. Olson, Lost to the Sounds of the World explores how place might be exhibited through music and how one might use music as a ‘place’ of its own: a place to think, a place to escape, or a place to discover. Scored for chamber orchestra, soprano, and electronics, this work is 33 minutes in length. The title is taken from a passage found in Olson’s book Listening Point, where he paints an arresting picture of finding fulfillment and wonder in nature. In the first chapter of the book, Olson describes his ideal plot of land—his Listening Point—one which contained everything he needed to be able to think clearly, to experience wonder, and to recapture curiosity. While he lists only his own personal criteria, he later emphasizes that everyone has a listening point of their own, a place which reflects their own needs and values. The first movement of the piece, titled all that is worth listening for, invites the listener to consider for themselves what kind of ‘place’ their own listening point might be. The piece begins with a field recording of rain I made while on a camping trip in Northern Minnesota, the same wilderness that Olson fought his entire life to protect. This rain is then filtered into a hazy chord which is later echoed by the percussion, piano, and soprano as they gradually enter the texture. When the rain clears, the soprano begins to sing text inspired by Olson’s list.
Also inspired by the artist Christi Belcourt and her environmentally conscious painting The Wisdom of the Universe, the second movement, titled one beating organism pulsing like a heart, represents the pulsations of life all around us. With this movement, I wanted to write music someone could get lost in, music with blurred edges, and music which is constantly becoming something new. Each instrument fades into and out of a sprawling tapestry of pulsations creating an immersive texture, a space for reflection, and a place to become lost in
THE IMPACT OF FAMILY MATH WEEK: A PLAYFUL ONLINE MATH INTERVENTION
No full textPositive parent-child interactions around mathematics at home can support children's achievement in school. While most research on families' engagement with resources at home has focused on physical materials, digital materials are a growing accessible resource for families. Online play-based programs have the potential to promote math in an engaging, motivating way. A unique attribute of digital technologies is that they can contain features with potential benefits for learning and joint engagement. One such feature is that digital technology can include embedded videos to easily provide families with tips and ways to support their children. The current study examined whether using different versions (i.e. with or without video tips) of a two-week online intervention, which promotes family math engagement using stories and games, affects families' beliefs about math and children's math knowledge.Second and third-graders (N = 123, Mage = 8.29) and their parent/caregiver (112 mothers, 9 fathers, 2 aunts) were randomly assigned to one of the following conditions: 1) use an online family-focused intervention with 10 days of content, 2) use the intervention with embedded video tips, or 3) no intervention condition. Families completed a pretest and posttest measure that assessed parents' math-helping self-efficacy, children's motivational framework, and arithmetic skills. Additionally, parents’ math anxiety was evaluated to determine potential moderation effects. Families self-reported their intervention program usage on both a posttest and daily logs.
Compared to the control condition, children in the intervention with embedded tips scored higher in their arithmetic knowledge at posttest. However, the intervention did not affect parents' math-helping self-efficacy beliefs or children's motivational framework. Additionally, no moderating effects of math anxiety or dosage were found. The results of this study provide some evidence of the effectiveness of supplemental online family math programs. Additionally, these results have practical implications for the types of programs practitioners may implement to promote positive family engagement
Multiscale Sensing of the Physical Cellular Environment: Phase-field Modeling and Experiments
No full textCells constantly interact with their physical environment by sensing and responding to mechanical and topographical cues. These cues span multiple scales, from subcellular interactions with the extracellular matrix to population-scale confinement in morphogenesis. Central to this process is the actin cytoskeleton, which serves as both a local force generator and a medium for signal integration and propagation. In this dissertation, I combine multiscale computational modeling with quantitative imaging to investigate how actin dynamics drive physical sensing from the scale of single protrusions to collective cellular behavior.
The actin cytoskeleton is the primary mechanism for generating forces that cause cell protrusions and guided migration. Using 12Z cells as a model of endometriosis, we examine how exposure to the biochemical signal estradiol alters actin organization and, consequently, cell morphology. High-resolution 3D imaging reveals that estradiol treatment increases protrusion size and disorder in actin dynamics, consistent with enhanced cellular invasiveness. These findings highlight how chemical signals modulate mechanical output through actin-based protrusions, reinforcing the role of actin as a key transducer of biochemical cues into physical motion.
At the subcellular scale, we use a 3D phase-field model to illustrate how cells exhibit unidirectional migration on asymmetric nanotopographies, with directionality controlled by actin polymerization rate and topographic scale. In this model, an asymmetric substrate alone can cause spontaneous polarization and reproduce the shape and guidance morphologies observed experimentally. These predictions align with a reanalysis of \textit{D. discoideum} experiments, revealing that guidance on subcellular sawteeth depends on both cell velocity and feature height. This agreement indicates that membrane deformation and local curvature sensing, driven by actin forces, are sufficient to bias migration in complex microenvironments.
To study how the actin cytoskeleton responds to chemical cues found in the extracellular matrix, we analyze epithelial cell migration on collagen-coated nanoridges. On nanoridges, collagen IV enhances actin alignment and cell elongation; however, actin guidance remains decoupled from the direction of migration. Therefore, additional mechanisms, such as focal adhesion dynamics, may contribute to directional sensing.
At larger scales, we develop a scalable 2D multicellular phase-field model incorporating excitable actin dynamics. This framework enables simulations of thousands of deformable cells on consumer hardware. The model spans a range of scales, allowing cell interaction, long-distance wave propagation, and information exchange. In this model, excitable intracellular mechanics, along with local physical interactions, can lead to emergent synchronization and local sensing of the shape of large-scale confinement.
Together, these findings suggest that actin serves as a mechanochemical interface for multiscale environmental sensing by driving local protrusions, integrating physical signals, and enabling collective coordination through excitable dynamics. Actin polymerization additionally acts as an upstream regulator of other cell functions, which opens avenues for future experimental studies on the effects of actin synchronization and pulsing on biophysical behavior. By linking cytoskeletal signaling to large-scale coordination, this work lays the foundation for identifying new physical mechanisms underlying biological processes that require coordination, such as metastasis and tissue morphogenesis
Essays on the Strategies of Economic Development
No full textI study how government policy shapes productive development. I focus on two strategies which were object of debate in early development economics: industrial policy and infrastructure projects.
In the first chapter, which is joint work with Chan Kim, we study how South Korea’s first “mission-oriented” R&D program, implemented between 1992 and 2001, shaped innovation and economic outcomes. Using new textual data and a language model to identify targeted and control technological classes, we exploit the fact that some of the planned research projects were not implemented because of budget shocks. We use a local projections event study to compare the outcomes of targeted technological classes to those of control classes. Despite the absence of differential trends before the program, by ten years after the extension of program support, future-citation-weighed patenting output in the targeted classes doubled and real exports tripled relative to the control technology classes. These results stand when we study cross-country evidence. Technological classes with less concentrated patenting output before the program drive our results. Using market-based patent valuations, we find that the program’s benefits exceeded its costs by over a factor of three. These findings suggest that technology policy was central to South Korea’s transition to a knowledge-intensive economy.
In the second chapter, which is joint work with Sebastián Galiani and Mateo Uribe-Castro, we study the impact of the Panama Canal on the development of Canada’s manufacturing sector from 1900 to 1939. Using newly digitized county-level data from the Census of Manufactures and a market-access approach, we exploit the plausibly exogenous nature of this historical episode to study how changes in transportation costs influence the process of structural transformation and manufacturing productivity. The reduced-form estimates show that lowered shipping costs increased manufacturing employment as a share of the population by increasing the number of manufacturing establishments, though not their average size, capital intensity, or skilled labor share. Manufacturing revenues grew 9% more in counties with market access gains at the 75th percentile, compared to counties with 25th percentile gains. Productivity grew by 13% more. These effects persist when we consider general equilibrium effects: the closure of the Canal in 1939 would result in economic losses equivalent to 1.86% of GDP, chiefly as a by-product of the restriction of the country’s access to international markets. Altogether, these results suggest that the Canal substantially altered the economic geography of the Western Hemisphere in the first half of the twentieth century.
In the third chapter, which is joint work with Sebastián Galiani and Mateo Uribe, we examine the influence of transportation infrastructure on migration decisions in the context of the Great Migration in the United States. Focusing on the opening of the Panama Canal in 1920, we isolate the effect of improved economic opportunities from reduced migration costs. Using full-count Census data, we find that Southern African American migrants preferred areas with enhanced market access, leading to higher inflows after 1920. The study highlights the interplay between migrant networks and labor markets in shaping migration patterns. These findings underscore the significance of local market conditions induced by improvements in local market access in influencing migration decisions during the Great Migration
PUSHING THE FRONTIERS OF RNA STRUCTURAL DYNAMICS USING SITE-SPECIFIC LABELING FOR SOLUTION NMR SPECTROSCOPY
No full textThe roles of RNAs (ribonucleic acids) in various cellular processes are underpinned by the unique architectures and range of dynamic motions they adopt. Subtle adjustments to RNA composition, structure, or even environment may confer profound changes to their stability and functions. Solution Nuclear Magnetic Resonance (NMR) Spectroscopy offers high-resolution and non-destructive approaches to explore these motions and structures, thereby enhancing our understanding of these biomolecules. However, the current median size of RNA structures probed by solution NMR spectroscopy is approximately 25 nucleotides (nts). The sparse distribution of high molecular weight RNA structures and dynamics data from NMR spectroscopy is ascribed to the lack of chemical shift diversity and line broadening. Here, the fundamental bases for line broadening effects are explored, accompanied by huge strides in the field to combat them. Recently, we have synthesized some site-specific isotopic labels that have demonstrated superior spectroscopic properties, thus, making them applicable to large RNAs. We showcase how the application of these isotopic labels expands our toolbox to study various RNA ranging in size from 27 nts to 232 nts by NMR spectroscopy
EN LA ENCRUCIJADA: ARBOLEDA DE LOS ENFERMOS Y DEAF STUDIES
No full textAs a subject of literature, deafness remains a theme that is subject to misrepresentation. A close-up examination of Teresa de Cartagena’s Arboleda de los enfermos (Grove of the Infirm) reveals elements of a universal Deaf experience, regardless of the historical or socio-economic context. Moreover, it reveals a longing for a community where solitude will be absent, where communication is barrier-free, where deafness is embraced, and where it is not considered a disease. Grounded on the expression “si bien lo mirardes” that Teresa emphasizes in the treatise, I contend that where the text is construed as at odds with contemporary perspectives on deafness and the Deaf experience as championed by Deaf Studies, namely, that deafness can be explored from the perspective of “gain,” rather than “deficiency,” shared points of convergence rather than contradictions exist on both sides. This is shown through a dialogue between both sides, considering that they are expressed in languages that, on the surface, appear antagonistic: religious and secular. Additionally, I argue that attitudes towards deafness and the Deaf experience in Teresa’s epoch do not differ significantly from their contemporary counterparts. Finally, I emphasize an interpretation of the “arboleda” as a conception of a genuine communal entity spurred by a longing from the author for such an entity. The proposition of a “saludable arboleda” within the text is thus construed as a space the Deaf can claim as their own, where they can live thoroughly dignified lives, absent the conception of deafness as a deficiency, as prevalent in mainstream society for which living a fulfilling life as a deaf person remains shrouded in mystery. Of this comes the notion of sociolinguistic and cultural identity claimed by members of said entity, a notion that is not far from a nationalistic claim, that is, the Deaf world, which both the author of Arboleda and the proponents of Deaf Studies invite “outsiders” to discover. This work contributes to this discovery journey
MYSIDS IN NEARSHORE FOOD WEBS OF CHESAPEAKE BAY TRIBUTARIES
No full textMysids, particularly Neomysis americana and Americamysis spp., are abundant crustaceans in the nearshore Chesapeake Bay that are important for connecting the microscopic and macroscopic portions of food webs. However, the effects of fish predation on mysid communities and prey of mysids are not well understood in these habitats. Our objectives were to 1) estimate the effect of predation of mysids by fishes in a shallow nearshore habitat of the Patuxent River in Chesapeake Bay and 2) determine the diet of mysids in situ in the St. Marys and Patuxent rivers. For objective 1, we conducted nighttime fish sampling using a 30×1.2 m beach seine, and mysids were sampled during the day using a 500 ?m-mesh epibenthic sled approximately weekly during August–September, 2023. Consumption of mysids was quantified by enumerating mysids found in the stomachs of each species of finfish and comparing estimates of consumption to estimates of mysid abundance. Only Americamysis spp. were observed during the study period, and estimated abundance fluctuated across sampling days. Estimated daily consumption varied among fish species, and the aggregate daily predation mortality rate of the local mysid population was estimated to be 1.1% d-1. We used DNA metabarcoding of the stomach contents of mysids sampled using an epibenthic sled and zooplankton nets from the St. Marys and Patuxent rivers to characterize mysids’ diets in situ. Dual-indexed amplicon-based high throughput sequencing was used to generate meta barcode libraries from the small subunit gene (18S) from pooled mysid stomachs. A small portion (0.18%) of our metabarcoding sequences were identified as non-mysid taxa, including copepods, fungi, macroalgae, microalgae, protists, segmented worms, tunicates, terrestrial plants, hydrozoans, and fish. Length of consumer mysid and time of sampling best predicted abundance of putative prey sequences. There was not a significant relationship between the length of consumer mysids and the putative prey they consumed. The results of this thesis are useful for building our knowledge of the Chesapeake Bay food web and of trophic niche of mysids
TOWARDS INVERSE RENDERING WITH GLOBAL ILLUMINATION
No full textObtaining 3D representations from real-world observations is a long-standing problem in computer vision/graphics with important applications in virtual/augmented reality. Inverse rendering is a technique for inferring 3D information—such as geometry, materials, and lighting—from a set of 2D images based on image formation principles. To recover scene parameters, it uses iterative gradient descent to minimize a loss between input images and images rendered by a differentiable renderer. Specifically, physically-based inverse rendering emphasizes accurate modeling of light transport physics, which can be prohibitively expensive. For example, inter-reflections between objects in a scene—known as global illumination—require simulating multi-bounce light transport. Differentiating this process across millions of pixels and parameters over many light bounces can exhaust memory, especially when using automatic differentiation, which stores a large transcript during the forward pass and differentiates through it in the backward pass. Consequently, many works in the literature simplify the problem by limiting light bounces to one or two, often resulting in inaccurate reconstructions.
This doctoral thesis focuses on improving the efficiency of global illumination algorithms using neural networks, with the ultimate purpose of making real-world inverse rendering more accessible. In particular, we present Neural Radiosity, a method of finding the solution of the rendering equation using a neural network by minimizing the residual of the rendering equation. We integrate Neural Radiosity in an inverse rendering pipeline and introduce a radiometric prior as a form of regularization term next to the photometric loss. As inverse rendering requires differentiating the rendering algorithm, we further apply the idea of Neural Radiosity to find the solution of the differential rendering equation. Finally, by coupling inverse rendering with generative AI, we present a method for synthesizing 3D assets. We use an image diffusion model to generate realistic material details on renderings of a scene, and backpropagate the new details into the scene description using inverse rendering. To achieve multi-view consistency using an image model, we propose to bias the attention mechanism without retraining the model. Together, our contributions advance the state-of-the-art in global illumination for inverse rendering, showing that this previously prohibitive goal is more attainable with neural methods. This thesis also demonstrates the potential of combining inverse rendering with generative AI for 3D content creation
A PERSON-CENTERED ANALYSIS OF TEMPERAMENT IN BEHAVIORALLY INHIBITED PRESCHOOLERS
No full textBehavioral inhibition (BI) is a biologically based temperament style marked by heightened sensitivity to novelty and fear in social situations (Kagan et al., 1984). For some, BI remains stable and contributes to later social emotional challenges, including increased risk for anxiety disorders (Fox et al., 2023). Identifying which children with BI are at greatest risk, and how individual and contextual factors influence outcomes, is essential for early intervention. However, gaps remain in understanding the diverse developmental pathways within this population.This study examined data from the parents of 254 behaviorally inhibited preschool-aged children. Latent Profile Analysis (LPA) was used to identify three subgroups based on broader temperament traits, including attentional focusing, perceptual sensitivity, high-intensity pleasure, anger, and inhibitory control. Profiles were then examined in relation to children’s social skills and parental beliefs, strategies, and attributions. Results revealed three distinct profiles that differed substantially from each other in social and emotional functioning: Regulated, Unregulated and Angry, and Typical BI.
BI profile membership significantly impacted social skills outcomes, accounting for about 30% of the variance in social skills scores, even after controlling for age and gender. Children with high anger and low regulation demonstrated more severe social difficulties than the Regulated and Typical BI groups, whereas those with stronger self-regulation were rated higher in social skills than both other profiles. The different profiles directly influenced how parents rated their children's social competencies, suggesting that children's temperament traits shape their observable behavior in ways that matter to caregivers. Differences in parenting beliefs and strategies did emerge but they were modest. Parents of Regulated children were less likely to attribute BI to internal traits and more likely to adopt a developmental perspective rather than focus on the situation when implementing strategies than parents of children in the Typical BI group. Parents of Unregulated and Angry children were more likely to anticipate unsuccessful outcomes and to use hands-on strategies compared to the Typical BI group. Parenting responses varied across situational vignettes, suggesting that strategies are both child and context dependent.
These findings support models emphasizing the heterogeneity within BI and highlight the importance of tailoring interventions to specific subpopulations within BI. This conclusion is strengthened by the finding that BI level in this population did not significantly differentiate between the three groups. This underscores the idea that other temperament factors and not merely level of BI above a certain cut-off matters for social and emotional outcomes