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Bearing the Burden of History: The Indo-Caribbean Madrasi Diaspora
No full textAfter the abolition of slavery in the British Empire in 1834, South Asians were shipped to plantations across the Caribbean as indentured workers. Indentured servitude—a system of forced migration and labor—produced the Indo-Caribbean diaspora. The Madrasis (named after their port of departure, Madras, i.e., Chennai, but hailing from different parts of southern India) are a religious minority within the Indo-Caribbean diaspora. They cohere around the goddess Mariamman and practice healing, drumming, and spirit possession rituals associated with her. Displaced by indentured servitude, persecuted by the colonial state for their religious practices, and ostracized by the Indo-Caribbean Hindu majority, Madrasis bear the burden of an exceptionally difficult transcontinental history. Since the 1980s, they have been moving to the United States as migrant workers. New York has emerged as the North American center of the Madrasi religion and diaspora.
To follow the Madrasis’ voyage across the dark waters of history and examine the role of religion in the making of the Indo-Caribbean Madrasi diaspora, I combine archival and ethnographic research conducted over the course of six years in New York, Guyana, and south India. Through archival work with maritime, missionary, and plantation records, I analyze how religion was employed as a category alongside race and caste to minoritize Madrasis. Through ethnographic fieldwork among Madrasi healers, drummers, and religious leaders in New York and Guyana, however, I demonstrate how the Madrasis themselves use religion in a very different way—to bear the burden of history. The Madrasis’ understanding of religion, history, and kinship, I argue, is shaped by their experiences of migration and creolization. From their diasporic position, the Madrasis imagine a transcontinental network of multibeing and multispecies kinship. They call this migrant network the “village.” This dissertation lies at the intersection of three geographical subfields in Religious Studies—South Asia, the Caribbean, and North America—and highlights the centrality of the study of religion to research on migration, diasporas, race, caste, and the environment
Integration of Solid Waste Upcycling and Carbon Sequestration for the Development of Sustainable Building Materials
No full textThis dissertation delves into the exploration of calcium carbonate polymorphs and silica-based materials upcycled from waste cement paste using a two-step extraction and carbonation process as supplementary cementitious materials (SCMs) to simultaneously achieve solid waste upcycling and carbon sequestration in the built environment. With the growing urgency to mitigate carbon emissions associated with the cement industry—one of the largest industrial contributors to anthropogenic CO₂ emissions globally—there is a pressing need to develop low-carbon alternatives that do not compromise the performance of concrete. This research is motivated by the potential of marrying carbon capture, utilization, and storage (CCUS) and alternative SCMs through CO₂ mineralization of industrial by-products and waste materials to lower the embodied carbon of cement and concrete. This approach addresses two critical issues: the reduction of construction and demolition (C&D) waste and the creation of highly reactive SCMs that can partially replace ordinary Portland cement (OPC). The dissertation is structured into two primary parts: the first focuses on the synthesis and potential applications of calcium carbonate polymorphs that can be derived from CO₂ utilization, and the second on the upcycling of waste cement paste into reactive silica-based materials.
The first part (Chapters 2, 3, and 4) of the dissertation centers on three anhydrous calcium carbonate polymorphs, calcite, aragonite, and vaterite, which were synthesized under controlled laboratory conditions. These polymorphs were first characterized comprehensively using analytical techniques including scanning electron microscopy (SEM) to observe their distinct morphologies, X-ray diffraction (XRD) to determine their crystalline structures, laser diffraction (LD) to analyze their particle size distribution, and Brunauer-Emmett-Teller (BET) analysis to measure their specific surface areas. The rheology, hydration, and stability of these polymorphs were then investigated after they were used as substitutes for Portland cement (OPC) in cement pastes at 10 wt% or 20% replacement level.
In Chapter 2, detailed rheological analyses were conducted, including rotational and oscillatory shear tests, to evaluate the influence of these polymorphs on the viscosity, yield stress, and structural buildup of cement pastes. Aragonite, with its needle-like crystals, was found to significantly enhance the static yield stress and structural build-up rates while having a minimal impact on dynamic yield stress, making it particularly suitable for applications requiring high thixotropy, such as 3D printing of concrete.
In Chapter 3, the polymorphs were found to affect the hydration kinetics of the cement pastes, with aragonite exhibiting the most pronounced accelerating effect, thereby contributing to faster early-age strength development. The differences in thermodynamic stability of the three polymorphs also resulted in slightly different phase assemblages as revealed via thermodynamic modeling, indicating potential beneficial effects of using metastable aragonite and vaterite in cement-based materials. The metastable vaterite was also found to be stabilized in cement systems despite its instability and tendency to convert to calcite in aqueous environments.
In Chapter 4, the mechanisms underlying the stabilization of vaterite in cement paste were explored with carefully designed experiments to construct model systems to decompose the complex cement-based systems and isolate dominating factors. The deposit and growth of cement-hydrated phases on the surface of vaterite and calcite seeds were found to be the dominant mechanisms preventing the transformation of vaterite to calcite, stabilizing metastable vaterite even in the presence of calcite seeding.
The second part (Chapter 5) of the dissertation investigates the reactivity of amorphous silica-based materials extracted from waste cement paste using a pH swing process as alternative SCMs. The upcycling process involves the leaching of calcium from waste cement paste, followed by a pH swing to precipitate undesired elements to isolate calcium for CO₂ mineralization. The resulting materials, referred to as "residue" and "precipitate," were thoroughly characterized and found to exhibit strong pozzolanic reactivity. When used as 10% replacements for OPC, these upcycled materials significantly improved the compressive strength of cement pastes, particularly at early ages. The study also explored the phase assemblages formed in these cement pastes after hydration via XRD and the chemical circularity of silicate structures during the upcycling and reincorporation processes. The results indicated that the incorporation of these upcycled SCMs can contribute to the hydration of cement pastes and enhance their mechanical properties, which proved the feasibility of using these upcycled materials as alternative SCMs.
Overall, this dissertation presents a comprehensive study on the potential of calcium carbonate polymorphs and upcycled silica-based materials as alternative SCMs to lower the embodied carbon of cement-based materials. Calcium carbonate polymorphs can be incorporated into cementitious materials to improve their rheological properties, hydration behavior, and mechanical performance, while amorphous silica-based materials exhibited high pozzolanic reactivity and contributed to the enhancement of compressive strength. This research paves a new way to decarbonize the built environment through the combination of solid waste upcycling and carbon sequestration, contributing to the global efforts to reduce the carbon footprint of the cement industry and promote a circular economy within the construction sector
Empirical and Behavioral Operations Management of Digital Healthcare and FinTech
No full textThis dissertation is motivated by two significant trends in the operations management of modern businesses. First, emerging technologies have transitioned traditional in-person services, such as healthcare, to online platforms. Second, advancements in machine learning and artificial intelligence, including large language models, provide promising tools to improve service quality. This dissertation aims to explore how emerging technologies and digitalization can be effectively utilized to manage customer behavior and the financial market.
In Chapter 1, I study operational factors that lead to service incompletions and customers' heterogeneous behaviors online versus in-person, using telemedicine as a canonical example. The adoption of online services, such as telemedicine, has increased rapidly over the last few years. To better manage online services and effectively integrate them with in-person services, we need to better understand customer behaviors under the two service modalities. Utilizing data from two large internal medicine outpatient clinics, I take an empirical approach to study service incompletion for in-person and telemedicine appointments respectively. I focus on estimating the causal effect of provider availability on service incompletion. When providers are unavailable, patients may be more likely to leave without being seen, leading to service incompletion. I introduce a multivariate probit model with instrumental variables to handle estimation challenges due to endogeneity, sample selection, and measurement error. The estimation results show that intra-day delay increases the telemedicine service incompletion rate, but it does not have a significant effect on the in-person service incompletion rate. This suggests that telemedicine patients may leave without being seen, while in-person patients are not sensitive to intra-day delay. I conduct counterfactual experiments to optimize the intra-day sequencing rule when having both telemedicine and in-person patients. This analysis indicates that not correctly differentiating the types of incompletions due to intra-day delays from no-shows can lead to highly suboptimal patient sequencing decisions.
In Chapter 2, I study the optimal usage of sunk cost, along with delay announcement, to mitigate service incompletion. Sunk-cost bias occurs when decisions are influenced by the time, energy, and money already invested, rather than considering the future costs necessary to achieve success. This phenomenon of "irrational behavior" is well-documented in decision-making studies and is generally recognized as a factor that can lead to suboptimal decisions. In this work, however, I investigate how sunk cost (and the behavioral bias associated with it) can be used as an operational lever to increase service completion rates in a congested service system. I run a controlled online experiment and find that the abandonment rate is significantly reduced for the group of participants who incur a larger sunk cost. To better capture the dynamics of service systems and their impact on customers' behavior, I study a queueing model with sunk cost and strategic customers, where customers experience a disutility of balking that is proportional to the sunk cost they incur. I characterize the equilibrium behavior of the customers, from which I further derive the optimal strategy for the service provider in terms of whether to provide real-time queue length information to customers as well as the optimal level of sunk cost to impose. The results show that the sunk cost strategy is effective only when waiting information is provided and that using a non-zero sunk cost is optimal when the system is moderately congested. Through a comprehensive numerical study, I demonstrate that implementing a non-zero sunk cost can substantially improve the throughput of the queuing system. In addition, I reveal an interesting asymmetric pattern in the robustness of the service provider's optimal policy when the customers' sensitivity to sunk cost cannot be accurately estimated, which suggests that if the service provider cannot accurately estimate the customer's sensitivity to sunk cost, using an underestimated value will give more robust performance improvements.
In Chapter 3, I quantify news novelty -- changes in the distribution of news text -- through an entropy measure, calculated using a recurrent neural network applied to a large news corpus. An increase in the novelty of news predicts negative stock market returns and negative macroeconomic outcomes over the next year. Entropy is a better out-of-sample predictor of market returns than a collection of standard measures. Cross-sectional entropy exposure carries a negative risk premium, suggesting that assets that positively covary with entropy hedge the aggregate risk associated with shifting news language. Entropy risk cannot be explained by existing long-short factors
Enhancement of energy carrier transport by coherent phonons in van der Waals semiconductors
No full textUnderstanding and controlling how phonons, or lattice vibrations, affect the behavior of photo-excited energy carriers is a longstanding goal of physical and materials chemistry. Thermal phonons, the observables in steady-state measurements such as infrared (IR) and Raman spectroscopies, are random fluctuations in nuclear displacements that scatter carriers, reducing electronic transport efficiency, and resulting in Joule heating. In contrast, coherent phonons exhibit synchronized atomic motion with maintained phase relations over extended spatial scales, often resulting in long-range vibrational energy propagation at well-defined group velocities.
This thesis demonstrates that coherent phonons can enhance the transport of photo-excited electronic carriers, including electrons and excitons – strongly bound electron-hole pairs – through dynamic trapping by the propagating deformation potential they create. Our primary material platform is tungsten diselenide (WSe₂), a van der Waals semiconductor prone to strong carrier–phonon interactions due to dimensional confinement and large deformation potential interactions. Using ultrafast spatiotemporal microscopy, we directly image nonequilibrium electronic carrier transport in the presence versus the absence of either coherent acoustic phonons or phonon-polaritons.
First, we show that laser-generated coherent acoustic phonons (sound/strain waves) in multilayer WSe₂ can carry free charges and excitons over microns at the speed of sound, paving the way for the miniaturization of surface acoustic wave-driven devices that are gaining increasing attention in quantum information science. Second, we show for the first time that hyperbolic phonon-polaritons in boron nitride can drag excitons in monolayer WSe₂across a van der Waals gap, leading to exciton transport at light-like speeds approaching the exciton Fermi velocity over picosecond scales. These studies highlight the potential of leveraging coherent species such as phonons to achieve orders-of-magnitude enhancement of electronic carrier transport via inter-particle interactions
Role of preconception nutrition supplements in maternal anemia and intrauterine growth: a systematic review and meta-analysis of randomized controlled trials
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Impaired intrauterine growth, a significant global health problem, contributes to a higher burden of infant morbidity and mortality, mainly in resource-poor settings. Maternal anemia and undernutrition, two important causes of impaired intrauterine growth, are prioritized by global nutrition targets of 2030. We synthesized the evidence on the role of preconception nutrition supplements in reducing maternal anemia and improving intrauterine growth. Methods We undertook a review of the randomized controlled trials (RCTs) assessing the effect of preconception nutrition supplements on maternal hemoglobin, an indicator to estimate maternal anemia, and markers of intrauterine growth including birth weight, length, head circumference, and small for gestational age. Additionally, we examined preterm birth as an important perinatal outcome. We searched PubMed, CINAHL, Web of Science, Cochrane Central, and Embase. We computed summary mean differences and risk ratios (RR) with 95% confidence intervals (CIs) using random-effect models. We employed I2 and Cochran’s Q test statistics to assess heterogeneity. We used a revised Cochrane risk-of-bias (RoB version 2.0) and GRADE (grading of recommendations, assessment, development, and evaluation) tools to assess the risk of bias and quality of evidence of eligible RCTs, respectively.
Results
We identified 20 eligible RCTs (n = 27,659 women). Preconception nutrition supplements (iron and folic acid, multiple micronutrients, and a lipid-based nutrient supplement) overall increased maternal hemoglobin by 0.30 g/dL ((0.03, 0.57); I2 = 79%; n=9). However, we did not find a significant effect of the supplements on birth weight (12.25 gm ((− 22.66, 47.16); I2 = 55%; n=10)), length (0.15 cm (− 0.26, 0.56); I2 = 68%; n = 5), head circumference (− 0.23 cm (− 0.88, 0.43); I2 = 84%; n=4), small for gestational age (RR 0.91 (0.80, 1.04); I2 = 31%; n=8), or preterm birth (RR 0.93 (0.69,1.25); I2 = 57%; n=12). In general, the quality of evidence was assessed as very low to moderate.
Conclusion
Preconception nutrition supplements studied to date appear to reduce maternal anemia. However, it is uncertain whether there are beneficial effects of the supplements on intrauterine growth. Low quality of evidence warrants future well-designed RCTs to produce solid scientific data, particularly of a more comprehensive package of preconception nutrition supplements that include both macro- and micronutrients. Systematic review registration PROSPERO CRD42023464966
Investigation of the causal relationship between patient portal utilization and patient’s self-care self-efficacy and satisfaction in care among patients with cancer
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The objective of this study was to examine the causal relationship between the usage of patient portals and patients’ self-care self-efficacy and satisfaction in care outcomes in the context of cancer care.
Methods
The National Institute’s HINTS 5 Cycle 1–4 (2017–2020) data were used to perform a secondary data analysis. Patients who reported being ever diagnosed with cancer were included in the study population. Their portal usage frequency was considered as an intervention. Patient’s self-care self-efficacy and satisfaction in care were the primary outcomes considered and they were measured by survey respondents’ self-reported information. A set of conditional independence tests based on the causal diagram was developed to examine the causal relationship between patient portal usage and the targeted outcomes.
Results
A total of 2579 were identified as patients with cancer or cancer survivors. We identified patient portals’ impact on strengthening patients’ ability to take care of their own health (P = .02, for the test rejecting which is necessary for the expected causal relationship, ie, the portal usage impacts the target outcome; P = .06, for the test rejecting which is necessary for the reverse causal relationship), and we identified heterogenous causal relationships between frequent patient portal usage and patients’ perceived quality of care (P = .04 and P = .001, for the tests rejecting both suggests heterogeneous causal relationships). We could not conclusively determine the causal relationship between patient portal usage and patients’ confidence in getting advice or information about health or cancer care related topics (P > .05 for both tests, suggesting inconclusive causal directions).
Conclusions
The results advocate patient portals and promote the need to provide better support and education to patients. The proposed statistical method exploits the potential of national survey data for causal inference studies
Management of asynchronous multifocal adult glioblastoma with loss of BRAFV600E -mutant clonality: a case report
Get PDFGlioblastoma (GBM) classification involves a combination of histological and molecular signatures including IDH1/2 mutation, TERT promoter mutation, and EGFR amplification. Non-canonical mutations such as BRAFV600E, found in 1–2% of GBMs, activate the MEK-ERK signaling pathway. This mutation can be targeted by small molecule inhibitors, offering therapeutic potential for GBM.
In this case report, we describe the management of a 67-year-old male with BRAFV600E -mutant GBM, who experienced both local clonal and distant non-clonal BRAFV600E -mutant recurrences. Initial treatment involved surgical resection followed by radiotherapy and temozolomide (TMZ). Subsequent recurrences were managed with re-resection and dabrafenib/trametinib combination therapy. Notably, a new, non-clonal BRAFV600E -negative tumor developed in a distant location, highlighting the challenge of clonal evolution and resistance in GBM management. The patient’s disease ultimately progressed despite multiple lines of therapy, including targeted inhibition.
Identifying mechanisms of resistance and tailoring flexible treatment approaches are essential for advancing outcomes in BRAFV600E -mutant GBM. This case emphasizes the value of molecular profiling in personalizing treatment for patients with multifocal disease. The evolving nature of these tumors requires persistent clinical monitoring and treatment adjustments based on tissue diagnostics
Three Essays on The Twin Problem of Electricity Markets
No full textThis dissertation explores two critical challenges in energy policy: the barriers to the optimal diffusion of abatement technologies and the persistence of energy poverty. The first chapter analyzes the adoption of Nitrogen Oxide (NOx) abatement technologies by U.S. electricity firms, focusing on how changes in environmental policy influence technology diffusion. The findings suggest that learning spillovers across peer plants within the same organization affect the diffusion of these technologies, which can ultimately distort policy outcomes.
The second chapter explores the unintended consequences of distance-based connection pricing policies in sub-Saharan Africa. These policies are expected to incentivize households to delay electricity take-up, thus prolonging energy poverty. This chapter presents theoretical and empirical evidence demonstrating how forward-looking households postpone take-up in anticipation of lower connection fees in the future, exploiting the dynamic incentives created by these pricing policies.
The final chapter investigates how grid reliability contributes to low ownership and use of electric appliances in sub-Saharan Africa. This chapter demonstrates that while households adapt to unreliable electricity, affordability remains a persistent barrier, and targeted affordability programs are necessary to support lower-income regions. In contrast, improving reliability should be targeted at higher-income areas. Collectively, the dissertation provides insights into the diffusion of abatement technologies and identifies obstacles to electrification programs in Africa. These insights offer valuable policy guidance for promoting the widespread adoption of new technologies while addressing the ongoing challenge of energy poverty
Substance use and traumatic events among Afghan general population: findings from the Afghanistan national mental health survey
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Substance use and traumatic events are prevalent in Afghanistan, but their relationship is under-investigated.
Methods A nationally-representative, cross-sectional survey was conducted in 8 regions of Afghanistan in 2017 (N = 4474). First, we examined the burden of substance use, and demographic correlates (e.g., gender, age) in the Afghan general population; second, we examined the association between traumatic and stressful experiences, including PTSD, and any substance use, tobacco use and sedative use.
Results
Substance use disorder is prevalent in Afghanistan, with prevalence of any substance use at 5.03%, tobacco use at 21.82%, and sedative use prevalence at 6.71%. Women and people with middle and high economic status were less likely to use any substance and tobacco, however, women were more likely use sedative compared to men. People who had collective violence and experienced any traumatic event more likely to use any substances, tobacco and sedative compared to their counterparts. Finally, individuals with PTSD, depression and generalized anxiety were more likely to use any substances, tobacco and sedative compared to individuals without these psychiatric disorders.
Conclusion
Substance use and dependence are prevalent in Afghanistan, an area with exposure to conflict and trauma for a majority of the population, underscoring the pervasive impact of trauma exposure on population health in this area. As resources are deployed to assist the Afghan population through conflict, attention to substance use and psychiatric disorders is needed to fully address population health
Footprints: Jewish Books Through Time and Place--Data 2025.01.09
No full textThis dataset comes from Footprints: Jewish Books Through Time and Place. Data includes provenance data (names, dates, locations) related to editions (title, publication date, publication place, standard identifier) of specific works (title, author) and related notes. The hierarchy for the dataset is composed of "footprints" which are found in "copies" of "imprints" of "literary works," with "footprint being the most specific data point and "literary work" being the most general. Wherever possible, the standard identifier for imprints is the Bibliography of the Hebrew Book. Downloaded on January 9, 2025