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Inferring IGM parameters from the redshifted 21-cm power spectrum using Artificial Neural Networks
No full textThe high redshift 21-cm signal promises to be a crucial probe of the state of the intergalactic medium (IGM). Understanding the connection between the observed 21-cm power spectrum and the physical quantities intricately associated with the IGM is crucial to fully understand the evolution of our Universe. In this study, we develop an emulator using artificial neural network (ANN) to predict the 21-cm power spectrum from a given set of IGM properties, namely, the bubble size distribution and the volume averaged ionization fraction. This emulator is implemented within a standard Bayesian framework to constrain the IGM parameters from a given 21-cm power spectrum. We compare the performance of the Bayesian method to an alternate method using ANN to predict the IGM parameters from a given input power spectrum, and find that both methods yield similar levels of accuracy, while the ANN is significantly faster. We also use this ANN method of parameter estimation to predict the IGM parameters from a test set contaminated with noise levels expected from the SKA-LOW instrument after 1000 hours of observation. Finally, we train a separate ANN to predict the source parameters from the IGM parameters directly, at a redshift of z = 9.1, demonstrating the possibility of a non-analytic inference of the source parameters from the IGM parameters for the first time. We achieve high accuracies, with R2-scores ranging between 0.898–0.978 for the ANN emulator and between 0.966–0.986 and 0.817–0.981 for the predictions of IGM parameters from 21-cm power spectrum and source parameters from IGM parameters, respectively. The predictions of the IGM parameters from the Bayesian method incorporating the ANN emulator leads to tight constraints on the IGM parameters
Craig Borowiak, \u3cem\u3eProfessor of Political Science\u3c/em\u3e
No full textSafri, M., Pavlovskaya, M., Healy, S., & Borowiak, C. (2025). Solidarity Cities: Confronting Racial Capitalism, Mapping Transformation. University of Minnesota Press. https://doi.org/10.5749/9781452974323https://scholarship.haverford.edu/featuredfac/1191/thumbnail.jp
Climate history modulates stress responses of common soil bacteria under experimental drought
No full textCaste-Associated Cuticular Chemistry Variation in the Paper Wasp \u3ci\u3eMischocyttarus pallidipectus\u3c/i\u3e
No full textExperimental Medicine: A Winter Break Reflection on Me-First Language Arts
No full textRogers reflects on an experimental English Language Arts (ELA) course he taught in 2015. The course, designed to explore identity and societal issues, was aimed at pushing beyond traditional teaching methods and engaging students in conversations about race, identity, and social justice. Influenced by the racial justice movements of the time, he sought to make learning more relevant and impactful. The class included readings from James Baldwin and W.E.B. Du Bois, encouraging students to confront their personal and collective identities while questioning oppressive structures. He invited his students to challenge conventional learning, with the hope of empowering them to claim their own understanding and spark social change. The course, intended as an experiment, emphasized the connection between self-awareness and the need for a broader societal transformation
Reencountering Trade Legacies , Indigenous Histories, and the Early Leopoldine Society Circle in the Vienna Weltmuseum
No full textShape Games
No full textShape Games is a film about play, abstraction, and enchantment. A series of strange and seemingly pointless activities unfold. Line drawings morph and shuffle; bottles of water are inverted and spilled, small rocks scrape across the ground; larger ones tumble across a rain drenched hill; wires bend; droplets are smeared across walls, paintings, and screens; cameras are chased—to the point of exhaustion. And a woman speaks. She describes strange things, chimeras and hybrids, objects and creatures, buzzing metamorphoses. She’s not talking about things we can see, not exactly, but her descriptions nonetheless hang in air, vivid and alluring. Are we seeing things, things that are there before us? Or are we seeing things, imagined things, hallucinated things, shadows and remainders? Yes and yes. The film asks the viewer to consider the rules that guide and constrain all of these activities, the labor and time it takes to perform them, the utility of this labor and the residues of this time. The world of Shape Games, in the words of the narrator, who is playing a game of her own, offers a bit of safety—certainty, comfort—but is also a trap, an enchanting one
Their Kindred Earth: Photographs by William Earle Williams
No full textThis exhibition explores the hidden histories embedded in the land, focusing on Connecticut’s overlooked connections to African American history. Through his powerful photography, William Earle Williams illuminates sites of enslavement, the Underground Railroad, and emancipation, many of which remain unmarked and forgotten. Inspired by his early mentorship with Walker Evans and his ongoing engagement with local historical initiatives, Williams returns as the Florence Griswold Museum’s 2023–25 Artist-in-Residence. His work uncovers the presence of those denied agency in recorded history, inviting viewers to reimagine familiar landscapes and consider the untold stories they hold. Printed catalog for the exhibition was published