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Essays on Labor Markets in Developing Countries
No full textThis dissertation comprises three essays on labor markets and economic development, unified by the theme of how geographic location – within cities, within countries, and across borders – shapes labor market outcomes.Chapter 1 investigates how caste-based marriage migration influences female labor force participation (FLFP) in India. Over 200 million Indian women have migrated for marriage, yet little is known about how these patterns affect their economic lives. Using confidential Census microdata, I show that migration is highly responsive to caste similarity but less so to wage differentials. Larger co-origin networks at the destination increase women’s probability of working, while wage-driven labor supply responses remain modest. I develop a spatial equilibrium model linking migration, post-marriage FLFP, and network formation. The model reveals that caste endogamy raises aggregate FLFP by coordinating women into destinations where networks enhance labor supply. Policy simulations suggest that strengthening women’s networks could substitute for this coordinating role.Chapter 2 examines how urban workers in developing cities adapt to extreme weather shocks, using high-frequency data from a location-based labor platform in Delhi. Daily earnings fall by 4% on extreme rainfall days, primarily due to reduced labor supply. Workers exhibit limited spatial adaptation and only partial income smoothing over time. Distributional effects are stark: income losses are three times larger in lower-income, peripheral neighborhoods. Infrastructure—especially drainage coverage and metro access—is strongly correlated with earnings resilience. These findings highlight how climate shocks interact with spatial inequality, constraining adaptive capacity and urban productivity.Chapter 3 studies the global economic value of cities and how it evolves with development. Using job histories of over 500 million workers across 191 countries, I implement a movers-based event-study design with individual and time-fixed effects. Moving to a higher-wage city yields large earnings gains: city effects explain 93% of cross-border and 45–73% of within-country wage changes. These effects correlate with city size, industrial diversity, and skill composition. In richer countries, stronger skill sorting reduces the role of place; in poorer countries, migration frictions continue to limit mobility. The findings point to large unrealized gains from migration in the developing world
Harnessing Dark Core Skyrmions for Optical Trapping and Imaging
Get PDFDark core Skyrmions are three-dimensional dark regions surrounded by vectorial light, created using polarization-dependent wavefront shaping, enabling enhanced uniformity, stability. We discuss their utility in microscopy and optical trapping
CDC42-effector interaction inhibitors alter patterns of vessel arborization in skin and tumors in vivo
No full textSkin tumors require a vascular supply to grow beyond 1 mm in depth, yet existing anti-angiogenesis agents are largely ineffective at treating melanoma tumors arising in skin. Using an approach that integrates antibody infusion, optical tissue clearing, multiphoton imaging, and vessel tracing, we identified the CDC42 GTPase RhoJ as a critical regulator of skin vessel arborization. Small molecules that target both RhoJ and CDC42 (CDC42 interaction inhibitors), but not those that target only CDC42 (CASIN), inhibit vessel branching in mouse skin in vivo and vascular organoids in vitro. This anti-vascular effect was not limited to skin, as CDC42 interaction inhibitors blocked melanoma tumor vascularization and inhibited tumor growth to a similar degree as Braf inhibitors. Taken together, this work identifies small molecules that target RhoJ as selective tumor anti-vascular agents. RhoJ-targeting drugs have a particular proclivity for blocking skin vascularization, nominating them as new treatments for inflammatory/vascular skin disease
Uncovering minimal pathways in melanoma initiation
No full textMelanomas are genetically heterogeneous, displaying mitogen-activated protein kinase mutations and homozygous loss of tumor suppressor genes. Mouse models combining such mutations produce fast-growing tumors. In contrast, rare, slow-growing tumors arise in mice combining Braf activation with heterozygous loss of Pten. Here we show that similar tumors can arise in albino mice bearing only a Braf mutation. Incidence kinetics suggest a stochastic event underlies tumorigenesis in tumors that arise with only a Braf mutation, yet de novo mutations or structural variants that could explain the incidence of most tumors could not be found. Single-cell transcriptomics of tumors identify a cell type resembling “neural crest-like” cells in human and mouse melanomas. These exist in normal mouse skin, expand upon Braf activation, and persist through serial transplantation; analyses of gene expression suggest they serve as precursors of malignant cells. This state may serve as an intermediate on a slow path to malignancy that may provide a diagnostically and therapeutically important source of cellular heterogeneity
Enhancing burn wound classification with ensemble learning using spatial frequency domain imaging applied to in-vivo porcine skin
Get PDFAssessing burn severity is crucial for appropriate care and treatment to reduce the risk of scarring and infection. Currently, practitioners rely on visual and tactile assessments, which can be subjective and potentially misleading. A more objective method recently employed in a swine model involves spatial frequency domain imaging (SFDI), a wide-field, noninvasive technique that deduces tissue optical properties using light propagation models. Recent studies have advanced this approach by using machine learning (ML) algorithms to predict burn severity from calibrated reflectance data o btained via SFDI, e liminating t he need f or l ight propagation m odels. Data from a porcine model of graded burns was collected using two distinct SFDI systems: the Reflect RS a nd Clarifi RS (Modulim Inc.). The Reflect R S o perates w ith e ight wavelengths f rom 4 70-850 nm modulated a t s ix spatial frequencies, five f rom 0 t o 0 .2/mm a t e qual i ncrements a nd a nother a t 0 .122/mm, w hile C larifi RS us es five wavelengths in the same range with modulation only at 850 nm (0 and 0.122/mm). This data was previously used exclusively to train simple ML models. In this study, we evaluate and compare ensemble learning algorithms against a support vector machine (SVM) for classifying burn severity in pigs. Specifically, we used random forest and Libra, the latter commonly used as a low spectral resolution brain tumor classifier for medical hyperspectral imaging. To ensure fair comparison, our methodology avoids overfitting, d iffering fr om pr evious st udies. Our results demonstrate that EL-based models can improve performance by up to 20% over SVM in metrics like F1-Score. Additionally, EL models generate more accurate classification maps with fewer false positives, identifying areas likely to heal after 28 days, thus offering clear and practical clinical insights
Protecting Maternal and Perinatal Healing Spaces: Proposing and Analyzing Global Support Methods that Increase the Wellbeing and Healing of Black Women and Birthing People
No full textThe World Health Organization has made Black communities the face of the maternal death narrative without consideration for their various cultural, ethnic, racial, and ancestral histories. There is not a one-size-fits-all support method that encompasses the various cultural, ethnic, racial, and ancestral histories of Black communities. So why do international organizations continue to write global guidance that is not contextualized to specific communities? Critiquing the 1987 Safe Motherhood Initiative and global guidance by the World Health Organization, global maternal health initiatives focus on the maternal death narrative rather than healing. Maternal and perinatal healing spaces are safe spaces where women and birthing people feel supported at all stages of their pregnancy; safe spaces that allow for healing from past birth trauma, ancestral healing, and healing from the global erasure of Black life, birth, and peace.Birthing support people, like doulas, use holistic practices and approaches to provide care within birthing spaces. They can help empower and support Black mothers and birthing people to find healing, rhythm, and community throughout the perinatal (prenatal, birthing, and postpartum) process. Their ability to holistically support mothers and birthing people’s intuitive ability to carry, birth, and feed a baby provides insight into how birthing support systems can change.In this paper, existing global literature is reviewed, sixteen conducted doula and birth worker interviews are analyzed using reflexive thematic analysis, and author Leila Chiddick’s participation in doula trainings is assessed. Leila creates The Holistic Birth Work Global Standard (HBW-GS) based on the sixteen interviews with doulas and birth workers. The HBW-GS is a guide to holistic care and practices, directly influenced by interviews, recommendations, and feedback by doulas and birth workers, centering the holistic care of mothers and birthing people. The HBW-GS intends to change how maternal and perinatal health is addressed globally and shift how the World Health Organization creates future global guidance
Headed Out Less: Analyzing Teen and Young Adult Travel Trends in the 21st Century
No full textSince the turn of the millennium, daily travel per person in the U.S. has been declining. Leading up to the pandemic, travel by older teens and young adults declined even more steeply than among older adults. After collapsing early in the pandemic, per capita travel by all ages has rebounded, but remains below pre-pandemic levels. To explore changes in personal travel, particularly among younger travelers, we examine National Household Travel Survey data from 2001, 2009, 2017, and 2022 to compare measures of everyday travel by youth (aged 15 to 29) with middle-aged adults (aged 30 to 59). The data presented in this report point to even lower levels of youth travel compared to pre-pandemic levels. Trips for all purposes have declined in absolute terms, especially for shopping/errands and, for youth in particular, social/recreational purposes. In relative terms, private vehicle use has increased, and travel by public transit and active modes has decreased. These shifts in personal travel – down overall and toward cars – suggest that pandemic-prompted travel shifts toward fewer out-of-home activities and increased use of information and communications technologies for shopping and other trips may be having enduring effects on personal travel, particularly among younger travelers
Thromboprophylaxis for Critically Ill Adolescents: A Multicenter Case-Control Study From the Children's Healthcare Advancements in Thrombosis Consortium.
Get PDFObjectivesTo determine if thromboprophylaxis, including pharmacologic, mechanical, or in combination, is associated with a hospital-acquired venous thromboembolism (HA-VTE) risk reduction among critically ill adolescents.DesignMulticenter case-control study from the Children's Healthcare Advancements in Thrombosis Consortium Registry and VTE risk-model validation study from January 2012 to July 2022.SettingThirty-two North American PICUs.PatientsCritically ill adolescents 12-19 years old including cases with radiographically confirmed HA-VTE (i.e., pulmonary embolism and deep venous thrombosis) and controls without HA-VTE.InterventionsPharmacologic (i.e., prophylactic anticoagulation) and mechanical (i.e., intermittent pneumatic compression) thromboprophylaxis.Measurements and main resultsOf 163 cases and 975 controls, 7.6% received pharmacologic, 23.5% mechanical, and 9.2% pharmacologic and mechanical thromboprophylaxis. Compared with controls, cases more frequently had central venous catheterization (89% vs. 21.1%), invasive ventilation (52.2% vs. 11.8%), longer median length of stay (29 d [interquartile range, 15-46 d] vs. 6 d [interquartile range, 3-10 d]), impaired mobility (72.6% vs. 22.1%), and infection (48.5% vs. 16%; all p < 0.001). Venous thromboembolism risk tiers (low, moderate, and high) were calculated using validated scoring criteria. Using multivariable logistic regression for HA-VTE risk accounting for additional prothrombotic covariates and among each VTE risk tier, pharmacologic and combined thromboprophylaxis, but not mechanical thromboprophylaxis alone, were independently associated with reduced HA-VTE risk.ConclusionsAmong critically ill adolescents, pharmacologic thromboprophylaxis alone or in combination with mechanical thromboprophylaxis, but not mechanical thromboprophylaxis alone, was associated with an HA-VTE risk reduction
Sarah Fielding’s The History of Ophelia: a female shakespearean gothic novel
Get PDFIn this thesis, I seek to recover Sarah Fielding’s much-forgotten 1760 novel The History of Ophelia. Fielding’s rhetorical moves anticipate the genre of women’s gothic, canonized three decades later by her descendent Ann Radcliffe. Her experimentation with genre–blending of fiction and nonfiction–provides her space to mirror, criticize, and reimagine Georgian era gender politics and female subjectivity. At the center of her work is Shakespeare. Fielding wields the bard’s work and his image as “nature’s poet” as a rhetorical tool to question which aspects of Georgian gender politics are natural and talk back to 18th-century interpretations of the bard’s work. Her novel serves as a parody of his famed Hamlet, which she hones as a rebuttal to her contemporary, Samuel Richardson’s, famous realist novel, Clarissa (1748). I argue that Fielding reveals the novel as a tool of feminist theory, a way to reinterpret, criticize, and recast these masculine works from a feminist point of view, ultimately serving as a medium through which to imagine a world where women have more authority, power, and voice. In an effort to illuminate Fielding’s layered rhetorical moves, I categorize her as a Female Shakespearean Gothic novelist, a label which appropriately recognizes her importance to and advancements of the novel form and relevance to a myriad of 18th-century genres.