Showing 1301 - 1310 of 5831 Items
A simple family of analytical trumpet slices of the Schwarzschild spacetime
Date: 2014-06-07
Creator: Kenneth A. Dennison, Thomas W. Baumgarte
Access: Open access
- We describe a simple family of analytical coordinate systems for the Schwarzschild spacetime. The coordinates penetrate the horizon smoothly and are spatially isotropic. Spatial slices of constant coordinate time t feature a trumpet geometry with an asymptotically cylindrical end inside the horizon at a prescribed areal radius R0 (with 0 < R0 M) that serves as the free parameter for the family. The slices also have an asymptotically flat end at spatial infinity. In the limit R0 = 0 the spatial slices lose their trumpet geometry and become flat - in this limit, our coordinates reduce to Painlevé- Gullstrand coordinates. © 2014 IOP Publishing Ltd.
Probing quantum Hall state homogeneity with surface waves
Date: 2013-01-01
Creator: M. E. Msall, W. Dietsche, S. Schmult, K. Von Klitzing
Access: Open access
- We study single quantum wells and matched density bilayer samples. Simultaneous measurements of the Hall voltages using low frequency lock-in techniques and of the changes in the 232 MHz (12.6 μm) SAW propagation measured with a vector network-analyzer allow comparison of the complex bulk and edge conductivities. The vtotal 1 bilayer state is seen directly in the SAW measurement only when the conductivity is below ∼ 6 × 10 -7 Siemens and is destroyed at moderate SAW powers by localized heating. The simultaneous reduction of the conductivity minima extracted from Hall data and from SAW data conclusively demonstrates that the vtotal 1 state disappears simultaneously throughout the bulk and not by the formation of competing domains or conducting filaments. © Published under licence by IOP Publishing Ltd.
Jigs, Reels, and “Realness”: An Investigation of Ideas of Authenticity and Tradition in New England French Canadian Music
Date: 2021-01-01
Creator: Lowell Ruck
Access: Open access
- Franco-American culture is increasingly recognized as an integral part of the heritage of Maine and New England, and has attracted growing academic attention in recent years. But while many scholars and cultural promoters focus on the French language in their work on this subject, few studies have considered the position of traditional music in Franco-American communities in the 21st century. This thesis examines French Canadian traditional music as it is played in New England and the ways in which musicians think about authenticity and tradition in their art. Using material from ethnographic interviews, it illuminates how musicians draw from individual, familial, and communal experiences and from past, present, and future conceptions of authentic tradition in their roles as cultural mediators. Ultimately, it suggests that players of French Canadian traditional music interact with this tradition in diverse ways, and that in doing so, they help to maintain the vibrancy of Franco-American cultural practices. La culture franco-américaine est reconnue de plus en plus comme partie intégrante de l’héritage du Maine et de la Nouvelle-Angleterre et attire maintenant l’attention académique. Mais même si beaucoup d’érudits et de promoteurs culturels ciblent la langue française dans leur travail sur ce sujet, peu d’études ont considéré la position de la musique traditionnelle dans les communautés franco-américaines du XXIe siècle. Cette thèse se concentre sur la musique traditionnelle canadienne-française de la Nouvelle-Angleterre et sur les façons dont les musiciens conceptualisent l’authenticité et la tradition dans leur art. En utilisant des entrevues ethnographiques, elle illumine comment les musiciens tirent des expériences individuelles, familiales et communautaires et des idées du passé, du présent et de l’avenir dans leurs rôles comme médiateurs culturels. Finalement, elle suggère que les joueurs de la musique traditionnelle canadienne-française interagissent avec cette tradition de plusieurs façons, et ce faisant, aident à maintenir la brillance des pratiques culturelles franco-américaines.

Possessing Her: Embodying Identity in Exorcism Cinema Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2021-01-01
Creator: Alicia Echavarria
Access: Access restricted to the Bowdoin Community
Critical Phenomena in the Gravitational Collapse of Electromagnetic Dipole and Quadrupole Waves
Date: 2021-01-01
Creator: Maria F. Perez Mendoza
Access: Open access
- We report on critical phenomena in the gravitational collapse of electromagnetic waves. Generalizing earlier results that focused on dipole electromagnetic waves, we here compare with quadrupole waves in axisymmetry. We perform numerical simulations of dipole and quadrupole wave initial data, fine-tuning both sets of data to the onset of black hole formation in order to study the critical solution and related critical phenomena. We observe that different multipole moments have different symmetries, indicating that the critical solution for electromagnetic waves cannot be unique, at least not globally. This is confirmed in our numerical simulations: while dipole data lead to a single center of collapse, at the center of symmetry, quadrupole data feature two separate centers of collapse on the symmetry axis, above and below the center of symmetry -- reminiscent of similar findings reported for critical collapse of vacuum gravitational waves. While the critical solution for neither the dipole nor the quadrupole data is exactly self-similar, we find that their approximate echoing periods appear to differ, as do the critical exponents. We discuss whether the centers of collapse found for dipole and quadrupole data might all have the same properties, which would suggest a ``local uniqueness" of the critical solution. Instead, we provide some evidence -- including the differing echoing periods and critical exponents -- suggesting that the critical solutions are distinct even locally. We speculate on the implications of our findings for critical phenomena in the collapse of vacuum gravitational waves, which share with electromagnetic waves the absence of a spherically symmetric critical solution.

Hypersensitization of Helicobacter pylori to Antibiotics Through Perturbation of Bacterial Glycan Armor Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2022-01-01
Creator: William J. Rackear
Access: Access restricted to the Bowdoin Community

Illumination, Inspiration, and Inquisition: The 15th and 16th century reception and reaction of Dante’s Divina Commedia in Spain This record is embargoed.
- Embargo End Date: 2025-05-19
Date: 2022-01-01
Creator: Francesca Mauro
Access: Embargoed

Sex- and age-specific susceptibility of parvalbumin neurons to DNA methylation in a model of early life adversity This record is embargoed.
- Embargo End Date: 2025-05-19
Date: 2022-01-01
Creator: Alissa Chen
Access: Embargoed