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Navigating Identity and Belonging: A Narrative Case Study of Indian American Educators in Online Professional Learning Networks
No full textThis study examines the experiences of Indian American educators as they navigate their intersecting cultural identities within online professional learning networks (PLNs). Guided by Asian Critical Race theory (AsianCrit) and employing a narrative case study methodology, this research explores how participants engage with online PLNs for professional growth, connection, and support, while confronting systemic barriers related to race and representation. Data were collected through in-depth interviews with four Indian American educators who actively participate in online PLNs. Participants’ narratives illuminate the tensions they experience between cultural heritage and professional expectations in predominantly white educational spaces, and the ways they seek affirmation, connection, and empowerment through online communities.
Findings reveal that while PLNs offer spaces for collaboration and growth, they often lack the cultural responsiveness needed to fully support racially minoritized educators. Participants described both the benefits of online engagement, including access to broader professional opportunities, and the limitations, including experiences of microaggressions, tokenization, and the need for additional emotional labor to educate others. The study concludes that PLNs must move beyond surface-level diversity initiatives to foster truly inclusive spaces that recognize and value the complex cultural identities of participants. This research contributes to the fields of educational leadership, teacher development, and critical race studies by highlighting the importance of culturally sustaining practices in professional learning environments.Interdisciplinary Learning and Teachin
Supernovae, by Chandra and XMM-Newton
No full textX-ray emission from supernovae can arise from multiple interactions during their evolution. The immediate explosion is sufficiently energetic to generate X-rays; so, too, is the impact of the shock as it runs into circumstellar matter from earlier mass loss phases. A considerable range of physics is on display during the evolution of such X-ray emission. This paper reviews some of the results of observing supernovae obtained by <i>XMM-Newton</i> and <i>Chandra</i> over the past 25 years. Each satellite has contributed significantly to the collection of observations and to our increased understanding of supernovae.Physics and Astronom
Climb On: Drawing Connections Between Bouldering and Mental Health
No full textAlthough rock climbing has enjoyed growing popularity on a global scale and research supports the physical and psychological benefits of exercise, there is limited research on the benefits of therapeutic climbing specifically. In this 30-minute poster presentation, we will define the sport of bouldering, review existing literature on therapeutic climbing, and discuss future implications for research.Counselor Education and Supervisio
Emission Modeling of the Jet/Accretion Flow/Black Hole Systems in GRMHD
No full textModeling emission in jet/accretion flow/black hole (JAB) systems is a crucial part of understanding the dynamical processes powering active galactic nuclei (AGN) known to reside in the center of a significant fraction of galaxies and underlie some of the most energetic processes in astrophysics. The Event Horizon Telescope (EHT) has made the first event-horizon scale images of a supermassive black hole (SMBH)- opening a new age of direct comparison of models of black hole influence on AGN processes and horizon-scale observation. While EHT’s primary JAB R-β Model has been rigorously tested, the alternative Critical-β Model has yet to be investigated in the same light despite promising advances. By modeling M87, a large, well-studied target, we can compare certain emission properties among alternative models. We also introduce a much-needed model to capture the phenomenology of shocks. We observe two flow states for the accreting plasma: Standard and normal evolution (SANE) and magnetically arrested disk (MAD). Computations are performed with two general relativistic radiative transfer (GRRT) codes to depict different morphological features throughout the evolution of the outflow and modeling of the spectral energy distribution (SED). We expand the Critical-β parameter space for M87 for the first time and discuss the implications. We find: 1.) As demonstrated in the library of images and corresponding spectra, the exponential decay in electron temperatures at high plasma β enables the Critical-β model to reduce bremsstrahlung contributions below observational constraints more efficiently than the R−β prescription, and 2.) Episodic flux eruption morphologies associated with various peaks in magnetic flux and troughs in mass accretion for magnetically arrested disks.Physics and Astronom
Heme Adventures: Roles In Catalysis and Structural Insights
No full textThe full text of this item is not available at this time because the author has placed this item under an embargo until May 15, 2030.Heme enzymes represent a vast class of biological catalysts that enable diverse oxidative transformations essential to life. This dissertation explores the roles of heme in catalysis through detailed biochemical, structural, and mechanistic studies of four distinct enzymes. Beginning with a comprehensive analysis of charge maintenance in non-heme iron oxygenases, the work highlights how ligand scaffolds and substrate interactions govern reaction outcomes. This is followed by subsequent investigations into tyrosine hydroxylase which reveal a novel free radical pathway, providing new insight into substrate oxidation. Structural and functional characterization of Mycobacterium tuberculosis catalase-peroxidase (KatG) identifies a unique indole-N-linked hydroperoxyl adduct that modulates enzymatic activity. The study of RufO, a heme enzyme implicated in rufomycin biosynthesis, suggests that tyrosine is not the native substrate, supported by spectroscopic, crystallographic, docking analyses. Finally, structural and spectroscopic studies of the streptococcal heme-binding protein HupZ demonstrate an unusual mode of heme coordination influenced by C-terminal tagging. Together, these studies underscore the diverse catalytic strategies enabled by heme and iron cofactors and offer broader implications for the design of biomimetic catalysts and therapeutic targets.Chemistr
Cool Concrete Sidewalk Pavements: Mitigating Urban Heat Island Effect with Integrating Phase Change Materials
No full textThe Urban Heat Island (UHI) effect contributes to increased energy consumption, elevated carbon emissions, deteriorating air quality, and public health risks in urban areas. This study explores the use of organic microencapsulated phase change materials (PCMs) in cool concrete sidewalks as a potential solution to mitigate UHI effects. The addition method, where paraffin oil-based PCM was incorporated based on the total weight of the control concrete sample at 0%, 5%, and 10%, was investigated through indoor and outdoor experiments. The indoor experiments followed both 4-hour and 8-hour heating and cooling cycles, while outdoor tests were conducted over an 8-hour continuous exposure period from 1 PM to 9 PM. Thermal and material properties were assessed using differential scanning calorimetry (DSC), laser flash analysis (LFA), and helium psychometry to evaluate heat capacity, diffusivity, and density. The results showed that PCM integration increased the heat capacity of the concrete, allowing it to absorb and store more thermal energy, while thermal diffusivity decreased, indicating a slower heat transfer rate through the material. Additionally, the incorporation of PCM slightly reduced the density of the concrete due to the lower density of the PCM compared to traditional mix components. These thermal property enhancements contributed to significant temperature reductions in the PCM-enhanced concrete, with the 10% PCM sample achieving up to 8°C reduction in 4-hour cycles, 4°C in 8-hour cycles indoors, and 7°C outdoors, while 5% PCM exhibited minimal temperature changes. Finite element simulations using a 3D thermal model with 6072 nodes and 1125 hexahedral elements (DC3D20 type) validated the experimental findings, showing delayed heat transfer and extended cooling effects in PCM-integrated concrete. These findings suggest that PCM-enhanced precast cool concrete sidewalks can be an effective strategy for UHI mitigation, improving thermal performance in urban infrastructure.Civil Engineerin
Enhancing Massive MIMO with Key-Based Physical Layer Security (PLS)
No full textThe full text of this item is not available at this time because the author has placed this item under an embargo until May 15, 2028.Massive Multiple-Input Multiple-Output (Massive MIMO) has emerged as a key enabling technology for Beyond 5G (B5G) and 6G networks, allowing for high spectral efficiency and the ability to serve multiple users within a cell through spatial multiplexing. Ensuring efficient and scalable security across all users remains a challenge. Physical layer security (PLS) based techniques offer a promising solution by leveraging the inherent properties of the wireless channel. In this work, we propose a security framework that adapts a key-based PLS scheme designed for single user MIMO (SU-MIMO) systems to the massive MIMO context. The proposed approach enables secure uplink and downlink transmission between a base station and multiple users. Simulation results show that the adapted key-based PLS protocol maintains Simulation results show that the adapted key-based PLS protocol maintains low error rates, ensures security across multiple users, and is resilient against passive eavesdropping techniques such as co-located and mobile eavesdroppers, with potential resistance to pilot contamination.Electrical and Computer Engineerin
Probing Heme-Dependent C-C Coupling and Oxygen Insertion Reactions
No full textHeme-dependent enzymes are highly ubiquitous in nature and are well known for their rich array of chemistry. The work discussed within this dissertation focuses largely on CYP121, a cytochrome P450 that catalyzes the intramolecular C-C coupling of its substrate cyclo(L-tyrosine-L-tyrosine) (cYY) and known to be necessary for the survival of Mycobacterium tuberculosis, and MarE, a member of the structurally-based heme-dependent aromatic oxygenase family (HDAO), that catalyzes the monooxygenation of its substrate β-methyl-L-tryptophan (β-Me-L-Trp). MarE plays a role in the biosynthesis of the 2-oxindole moiety found in natural products such as maremycins, which have antibiotic activity, and spirooxoindoles, which are used as a scaffold for the development of anticancer therapeutics.
The work presented here utilizes strategic design of small-molecule mechanistic probes, spectroscopy, structure, and biochemical methods to investigate enzyme mechanism by altering reaction kinetics to trap intermediates and probing reaction outcomes by mutational and product analysis in an effort to correlate structure to function. In CYP121, several late-stage intermediates of the catalytic cycle were structurally and spectroscopically characterized, beginning with the hydroxylation of a methylated substrate analog, to the assignment of a near side-on ferric-hydroperoxo, to the putative cYY-based radical intermediate which provides evidence for a novel radical transfer mechanism. Probing the dioxygenated products of the MarE reaction, how ascorbate dictates monooxygenation of the substrate, and the corresponding mutational analysis expands on the functional diversity of HDAO family enzymes and how its structural similarity to tryptophan 2,3-dioxygenase does not necessarily chain it to dioxygenation chemistry.Chemistr
PREDICTING GEOLOCATION USING TWEET TEXT THROUGH BERT AND MULTITASK LEARNING
No full textGeolocation prediction from textual data is a critical task in various domains, including social media analysis, disaster response, and intelligence gathering. This project presents a deep learning-based approach to estimate geographic coordinates from textual inputs using a multi-output regression model. The model leverages natural language processing (NLP) techniques to extract location-relevant features and predicts latitude and longitude pairs with an associated confidence distribution. A weighted combination of multiple predicted locations is used to improve accuracy and account for geospatial ambiguity. The training process utilizes large-scale datasets filtered through the Natural Earth Countries dataset to focus on U.S.-based locations. To enhance performance, clustering techniques were employed for data balancing, and a softmax-weighted loss function was introduced to refine multi-point predictions. The system was implemented using PyTorch and optimized for GPU-based training to accelerate computation. Experimental results demonstrate improvements in geolocation accuracy over traditional baselines, highlighting the effectiveness of the proposed architecture in real-world applications.Artificial Intelligenc
A double-edged sword?: Digitalization, health disparities, and the paradoxical case of e-pharmacy in Ghana
No full textObjective
With the ongoing push for greater digitalization of healthcare in low- and middle- income countries (LMICs), the larger questions around who will benefit most from such efforts and what elements of disparities and inequities may further be created or reinforced are often overlooked. This study was undertaken to assess a pioneering e-pharmacy initiative in Ghana that aimed to explore issues of access and disparities in relation to pharmaceutical services.
Method
The study used a qualitative research design where semi-structured interviews were conducted virtually with 21 licensed community pharmacists recruited through purposive and snowball sampling techniques. The data were analyzed using inductive thematic analysis approach.
Results
Pharmacists recognized the transformative potential of e-pharmacies, particularly in resource constrained regions that face issues of pharmacy and healthcare deserts. However, drawing on their experiential knowledge, they highlighted the paradoxes and challenges of promoting digitalization of healthcare in a country characterized by poor infrastructure, poverty, and multiple intersecting layers of inequities, as well as digital divides and low digital/health literacy. In the absence of adequate infrastructure, funding support and regulation, the possibility of local pharmacies, often the first point of care, being replaced by big corporations was feared. Participants also cautioned to steer the discourse of e-pharmacy away from access, pricing, and convenience to safety and quality.
Conclusion
Digitalization of healthcare and e-pharmacies holds tremendous potential in the LMICs. However, such technological initiatives, if implemented without proper groundwork and adequate support, would run the risk of creating and exacerbating health disparities, especially in sub-Saharan Africa. A bottom-up approach, through grassroot engagement and implementation science, tethered to building safe, affordable, and equitable infrastructure and access to care will be essential for the success of e-pharmacy and other digitalization initiatives in the region and beyond. This research has direct implications for public health, policy, and pharmaceutical care.Communicatio