The Impact of Minority Representation at Mortgage Lenders

We study links between the labor market for loan officers and access to mortgage credit. Using novel data matching the (near) universe of mortgage applications to loan officers, we find that minorities are significantly underrepresented among loan officers. Minority borrowers are less likely to complete mortgage applications, have completed applications approved, and to ultimately take-up a loan. These disparities are significantly reduced when minority borrowers work with minority loan officers. Minority borrowers working with minority loan officers also have lower default rates. Our results suggest that minority underrepresentation among loan officers has adverse effects on minority borrowers’ access to credit.Author's Origina

Altered Social Information Processing and Behavioral Responsivity as Mechanisms Linking Childhood Experiences of Violence with Psychopathology

In the United States, over half of youth experience or witness interpersonal violence. Extensive research links these experiences with heightened risk for developing mental health problems throughout life. Despite advances in our understanding of how early violence exposure impacts mental health, there remains a need to refine translational mechanisms to guide intervention efforts. This dissertation leverages theory and methods from clinical, developmental, and social psychology to characterize the interplay of early-life violence exposure with the development of information processing patterns that hold relevance for mental health and patterns of aggressive behavior that may underlie or maintain “cycles of violence.” Paper 1 utilizes a three-timepoint longitudinal design, developmental sample, and experimental manipulation to test whether alterations in implicit bias for novel groups is a mechanism linking childhood violence exposure with prospective risk for internalizing symptoms. Paper 2 attempts to replicate and extend findings from Paper 1 in a larger sample of young adults to test whether alterations in implicit social cognition following violence exposure persist into adulthood, and to examine whether early violence exposure similarly impacts affect biases relevant to social cognition and mental health. Paper 3 aims to characterize behavioral risk factors for becoming violence-involved that are informed by similar social and affective information processing biases using an ecologically-valid aggression paradigm in a high-risk adolescent sample. Together, findings from this dissertation suggest that subconscious intergroup biases, such as implicit bias for novel groups, may be an important mechanism linking early violence exposure with risk for mental health, and implicate the development of aggressive response styles as a risk factor for perpetrating violence. Future directions are discussed throughout and in the general discussion.Psycholog

Residential Battery Storage - Reshaping the Way We Do Electricity

In this study, we investigate households’ investments in behind-the-meter battery storage alongside rooftop solar and examine the effects of these batteries on consumers, the power market, and environmental emissions. We develop a structural estimation model of residential electricity usage that separates observed demand and consumption preferences and lets us estimate a non-financial utility that households may have for using self-generated solar power over grid-procured electricity. We call this utility nonmarket valuation, provide evidence that it is driven by sustainability and autarky desires, and relate it to the early adoption of residential storage. Applying this model to a novel data set of German households, we find that the median household has a nonmarket valuation of 0.29€ per kilowatt hour (kWh). We then show that owning storage increases a household’s electricity demand (storage rebound) and marginally increases the emissions by 57 kg CO2 / year / kWh of battery capacity. However, batteries may reduce emissions if solar penetration in the grid is sufficiently high. Lastly, we estimate that, at future technology costs, 2023 European electricity prices, and without subsidies, investing in storage is optimal for 54% of households, which would reduce the residential grid load by 38%, but, counterintuitively, also make it more variable.Accepted Manuscrip

Shapeshifting: A Practical Guide

"Shapeshifting: A Practical Guide" explores shapeshifting as an embodied and ethically grounded practice that expands our understanding of selfhood, kinship, belonging, and care. Drawing from physical theater and play traditions such as Jacques Lecoq and InterPlay, Buddhist teachings on no-self, and animist worldviews including those of the Yukaghir hunters of Siberia, I argue that intentional shapeshifting can be a method for softening the boundaries of the self and cultivating a felt sense of relationality with other beings, whether real or imaginary. Through both scholarly analysis and experiential inquiry, I investigate how mimetic embodiment allows practitioners to move beyond imitation into internalization: not merely “playing at” being a tree, animal, or fictional character, but temporarily being that entity from within. Shapeshifting becomes a form of "kinning"—an imaginative and physical process that reveals our interdependence with the world. However, this practice is not without its risks. The project also considers the psychological and cultural ethics of shapeshifting, particularly when engaging with real people or culturally significant identities. In response, I explore the importance of protective rituals, humble intention, and conceptual grounding to guide safe and responsible practice. In addition to theoretical reflection, the project includes a section devoted to shapeshifting practices I designed, both for solo exploration and group contexts. These practices offer structured, accessible ways for participants to explore the transformative potential of the work. Ultimately, shapeshifting emerges not as escapism, but as a method of coming into deeper contact with life itself. It is a method that trains us in empathy, flexibility, and moral responsiveness by means of the body.Author's Origina

Subir Sachdev - 20 selected papers with commentaries

PhysicsAuthor's Origina

The Still Point of the Turning World: Advancing Polarity Theory and Praxis

This thesis explores the potential of polarity—mutually dependent opposites—as a transformative practice at both individual and collective levels. It outlines the framework of Integral Polarity Practice (IPP), originally conceived by John T. Kesler and further developed by the author. IPP is an embodied approach that draws from diverse contemplative traditions, Jungian therapeutic methods, developmental psychology, and other disciplines to reveal the creative tensions that pulse throughout human life. At its heart, IPP emphasizes the importance of discovering the “still point” between polarities—a space where polar tension gives way to spaciousness, creativity, and perhaps above all, love. Paradoxically, polarity practice becomes a path of discovering unity within multiplicity, ultimately radiating as “flowing oneness,” or “virtue.” Drawing on the work of contemporary polarity practitioners and theorists, this thesis situates IPP within the broader landscape of polarity frameworks, clarifying its distinct contributions and innovations. Through personal narrative, theoretical exposition, and experiential insight, the author presents IPP as an evolution in polarity understanding—both conceptually and practically. It argues that IPP offers a path of transformation capable of revealing the prior Wholeness to which all human beings inescapably belong.Author's Origina

How the SO(5) k=1 WZW near-CFT3 explains the underdoped regime of the cuprate high temperature superconductors

PhysicsAuthor's Origina

Combatting Collusion Between Reinforcement Learning Agents in Electricity Markets

When markets are well behaved, we expect firms to produce at the point where marginal revenue matches marginal cost. Collusive behavior, on the other hand, arises when firms produce less than this, leading to elevated prices, lower social welfare and higher industry profits. It is interesting, then, that collusive behavior has been observed between reinforcement learning (RL) agents that act to set prices for goods across repeated interactions in simple, simulated markets. This behavior is the convergence toward a market equilibrium that has lower social welfare or higher industry profits than what is considered a Nash equilibrium for the reinforcement learning agents. In this project, I create a simplified model of an electricity market to confirm the collusive behavior of RL agents, comparing theoretical baselines of profit and welfare to the result of using Q-Learning agents. I then study the effect of various market interventions, in both this simplified model and Abada and Lambin’s model \cite{Abada-Lambin}. The interventions I consider include a) the introduction of a welfare-maximizing agent, b) setting limits on battery and output capacity, c) the use of taxation, and d) a reward-punishment scheme. In order to assess the suitability of each intervention, a game-theoretic equilibrium is calculated for each intervention and compared to theoretical baselines. This is computed using quadratic program solvers and Scipy optimization packages. The intervention is then implemented in an OpenAI Gym environment to confirm or reject the game-theoretic improvements that were demonstrated. For the welfare-maximizing agent intervention, it was also implemented on the Abada and Lambin model to explore how agents react to the intervention in a more complex environment. A first result, in both the simplified model as well as Abada and Lambin’s model, is that the introduction of a welfare-maximizing agent fails to provide a desired improvement in social welfare. Likewise, creating restrictions on battery and output capacity fails to provide a desired improvement in social welfare. Rather, I show that a promising direction is to make use of a suitable taxation or reward-punishment scheme, with this able to improve social welfare in both models.Applied Mathematic

Efferocytosis drives a tryptophan metabolism pathway in macrophages to promote tissue resolution

It will be great for us to have such a waiver statement as below: While all authors subscribe to NIH Open Policy, Harvard Medical School (HMS) does not demand that a non-HMS lead author of a manuscript on which an HMS co-author appears must pay the fee for the journal's own open access program.Author's Origina