Showing 2031 - 2040 of 5831 Items
Level-rank duality of untwisted and twisted D-branes
Date: 2006-05-15
Creator: Stephen G. Naculich, Howard J. Schnitzer
Access: Open access
- Level-rank duality of untwisted and twisted D-branes of WZW models is explored. We derive the relation between D0-brane charges of level-rank dual untwisted D-branes of over(su, ̂) ( N )K and over(sp, ̂) ( n )k, and of level-rank dual twisted D-branes of over(su, ̂) ( 2 n + 1 )2 k + 1. The analysis of level-rank duality of twisted D-branes of over(su, ̂) ( 2 n + 1 )2 k + 1 is facilitated by their close relation to untwisted D-branes of over(sp, ̂) ( n )k. We also demonstrate level-rank duality of the spectrum of an open string stretched between untwisted or twisted D-branes in each of these cases. © 2006 Elsevier B.V. All rights reserved.
Event-related potential correlates of interference effects on recognition memory
Date: 2008-02-01
Creator: Kenneth A. Norman, Katharine Tepe, Erika Nyhus, Tim Curran
Access: Open access
- The question of interference (how new learning affects previously acquired knowledge and vice versa) is a central theoretical issue in episodic memory research, but very few human neuroimaging studies have addressed this question. Here, we used event-related potentials (ERPs) to test the predictions of the complementary learning systems (CLS) model regarding how list strength manipulations (strengthening some, but not all, items on a study list) affect recognition memory. Our analysis focused on the FN400 old-new effect, a hypothesized ERP correlate of familiarity-based recognition, and the parietal old-new effect, a hypothesized ERP correlate of recollection-based recognition. As is predicted by the CLS model, increasing list strength selectively reduced the ERP correlate of recollection-based discrimination, leaving the ERP correlate of familiarity-based discrimination intact. In a second experiment, we obtained converging evidence for the CLS model's predictions, using a remember/know test: Increasing list strength reduced recollection-based discrimination but did not reduce familiarity-based discrimination. Copyright 2008 Psychonomic Society, Inc.
Components of the Springer fiber and domino tableaux
Date: 2004-02-15
Creator: Thomas Pietraho
Access: Open access
- Consider a complex classical semisimple Lie group along with the set of its nilpotent coadjoint orbits. When the group is of type A, the set of orbital varieties contained in a given nilpotent orbit is described a set of standard Young tableaux. We parameterize both, the orbital varieties and the irreducible components of unipotent varieties in the other classical groups by sets of standard domino tableaux. The main tools are Spaltenstein's results on signed domino tableaux together with Garfinkle's operations on standard domino tableaux. © 2004 Elsevier Inc. All rights reserved.
Level-rank duality of the U(N) WZW model, Chern-Simons theory, and 2d qYM theory
Date: 2007-06-01
Creator: Stephen G. Naculich, Howard J. Schnitzer
Access: Open access
- We study the WZW, Chern-Simons, and 2d qYM theories with gauge group U(N). The U(N) WZW model is only well-defined for odd level K, and this model is shown to exhibit level-rank duality in a much simpler form than that for SU(N). The U(N) Chern-Simons theory on Seifert manifolds exhibits a similar duality, distinct from the level-rank duality of SU(N) Chern-Simons theory on S 3. When q ≤ e2πi/(N+K), the observables of the 2d U(N) qYM theory can be expressed as a sum over a finite subset of U(N) representations. When N and K are odd, the qYM theory exhibits N K duality, provided q ≤ e2πi/(N+K) and θ ≤ 0 mod 2π/(N + K). © SISSA 2007.
An Analysis of Hezbollah’s Media Platforms, Focusing on Themes, Narratives and Strategy Access to this record is restricted to members of the Bowdoin community. Log in here to view.
- Restriction End Date: 2025-06-01
Date: 2020-01-01
Creator: Nichole Irving
Access: Access restricted to the Bowdoin Community
A 60 yr record of atmospheric carbon monoxide reconstructed from Greenland firn air
Date: 2013-08-19
Creator: V. V. Petrenko, P. Martinerie, P. Novelli, D. M. Etheridge, I., Levin, Z. Wang, T. Blunier, J. Chappellaz, J. Kaiser, P. Lang, L. P. Steele, S. Hammer, J. Mak, R. L. Langenfelds, J. Schwander, J. P. Severinghaus, E. Witrant, G. Petron, M. O. Battle, G. Forster, W. T. Sturges, J. F. Lamarque, K. Steffen, J. W.C. White
Access: Open access
- We present the first reconstruction of the Northern Hemisphere (NH) high latitude atmospheric carbon monoxide (CO) mole fraction from Greenland firn air. Firn air samples were collected at three deep ice core sites in Greenland (NGRIP in 2001, Summit in 2006 and NEEM in 2008). CO records from the three sites agree well with each other as well as with recent atmospheric measurements, indicating that CO is well preserved in the firn at these sites. CO atmospheric history was reconstructed back to the year 1950 from the measurements using a combination of two forward models of gas transport in firn and an inverse model. The reconstructed history suggests that Arctic CO in 1950 was 140-150 nmol mol-1, which is higher than today's values. CO mole fractions rose by 10-15 nmol mol-1 from 1950 to the 1970s and peaked in the 1970s or early 1980s, followed by a ≈ 30 nmol mol-1 decline to today's levels. We compare the CO history with the atmospheric histories of methane, light hydrocarbons, molecular hydrogen, CO stable isotopes and hydroxyl radicals (OH), as well as with published CO emission inventories and results of a historical run from a chemistry-transport model. We find that the reconstructed Greenland CO history cannot be reconciled with available emission inventories unless unrealistically large changes in OH are assumed. We argue that the available CO emission inventories strongly underestimate historical NH emissions, and fail to capture the emission decline starting in the late 1970s, which was most likely due to reduced emissions from road transportation in North America and Europe. © Author(s) 2013.
Noninvasive Memory Modulation Via Targeted Theta TACS Entrainment of the Frontoparietal Network Access to this record is restricted to members of the Bowdoin community. Log in here to view.
- Restriction End Date: 2026-06-01
Date: 2021-01-01
Creator: Brandon S Lee
Access: Access restricted to the Bowdoin Community