Showing 3441 - 3450 of 5831 Items
Matrix-model description of N = 2 gauge theories with non-hyperelliptic Seiberg-Witten curves
Date: 2003-12-08
Creator: Stephen G. Naculich, Howard J. Schnitzer, Niclas Wyllard
Access: Open access
- Using matrix-model methods we study three different N=2 models: U(N)×U(N) with matter in the bifundamental representation, U(N) with matter in the symmetric representation, and U(N) with matter in the antisymmetric representation. We find that the (singular) cubic Seiberg-Witten curves (and associated Seiberg-Witten differentials) implied by the matrix models, although of a different form from the ones previously proposed using M-theory, can be transformed into the latter and are thus physically equivalent. We also calculate the one-instanton corrections to the gauge-coupling matrix using the perturbative expansion of the matrix model. For the U(N) theories with symmetric or antisymmetric matter we use the modified matrix-model prescription for the gauge-coupling matrix discussed in our paper: Cubic curves from matrix models and generalized Konishi anomalies (hep-th/0303268). Moreover, in the matrix model for the U(N) theory with antisymmetric matter, one is required to expand around a different vacuum than one would naively have anticipated. With these modifications of the matrix-model prescription, the results of this paper are in complete agreement with those of Seiberg-Witten theory obtained using M-theory methods. © 2003 Elsevier B.V. All rights reserved.
Suspense-optimal college football play-offs
Date: 2014-01-01
Creator: Jarrod Olson, Daniel F. Stone
Access: Open access
- U.S. college football’s traditional bowl system, and lack of a postseason play-off tournament, has been controversial for years. The conventional wisdom is that a play-off would be a more fair way to determine the national champion, and more fun for fans to watch. The colleges finally agreed to begin a play-off in the 2014-2015 season, but with just four teams, and speculation continues that more teams will be added soon. A subtle downside to adding play-off teams is that it reduces the significance of regular season games.We use the framework of Ely, Frankel, and Kamenica (in press) to directly estimate the utility fans would get from this significance, that is, utility from suspense, under a range of play-off scenarios. Our results consistently indicate that play-off expansion causes a loss in regular season suspense utility greater than the gain in the postseason, implying the traditional bowl system (two team play-off) is suspense-optimal. We analyze and discuss implications for TV viewership and other contexts.
Erratum: Sutural loosening and skeletal flexibility during growth: Determination of drop-like shapes in sea urchins (Proceedings of The Royal Society of London B (February 7, 2002) 269 (215-220))
Date: 2002-12-22
Creator: Amy S. Johnson, Olaf Ellers, Jim Lemire, Melissa Minor, Holly A., Leddy
Access: Open access
Prediction of "fear" acquisition in healthy control participants in a de novo fear-conditioning paradigm
Date: 2007-01-01
Creator: Michael W. Otto, Teresa M. Leyro, Kelly Christian, Christen M. Deveney, Hannah, Reese, Mark H. Pollack, Scott P. Orr
Access: Open access
- Studies using fear-conditioning paradigms have found that anxiety patients are more conditionable than individuals without these disorders, but these effects have been demonstrated inconsistently. It is unclear whether these findings have etiological significance or whether enhanced conditionability is linked only to certain anxiety characteristics. To further examine these issues, the authors assessed the predictive significance of relevant subsyndromal characteristics in 72 healthy adults, including measures of worry, avoidance, anxious mood, depressed mood, and fears of anxiety symptoms (anxiety sensitivity), as well as the dimensions of Neuroticism and Extraversion. Of these variables, the authors found that the combination of higher levels of subsyndromal worry and lower levels of behavioral avoidance predicted heightened conditionability, raising questions about the etiological significance of these variables in the acquisition or maintenance of anxiety disorders. In contrast, the authors found that anxiety sensitivity was more linked to individual differences in orienting response than differences in conditioning per se. © 2007 Sage Publications.
Cells and constructible representations in type B
Date: 2008-10-13
Creator: Thomas Pietraho
Access: Open access
- We examine the partition of a finite Coxeter group of type B into cells determined by a weight function L. The main objective of these notes is to reconcile Lusztig's description of constructible representations in this setting with conjectured combinatorial descriptions of cells.
An information theoretical approach to task-switching: Evidence from cognitive brain potentials in humans
Date: 2008-03-28
Creator: Francisco Barceló, José A. Periáñez, Erika Nyhus
Access: Open access
- This study aimed to clarify the neural substrates of behavioral switch and restart costs in intermittently instructed task-switching paradigms. Event-related potentials (ERPs) were recorded while participants were intermittently cued to switch or repeat their categorization rule (Switch task), or else they performed two perceptually identical control conditions (NoGo and Oddball). The three tasks involved different task-sets with distinct stimulus-response associations in each, but identical visual stimulation, consisting of frequent colored shapes (p = 0.9) and randomly interspersed infrequent black shapes (p = 0.1; '+' and 'x' symbols). Behavioral restart costs were observed in the first target responses following all black shapes in the Switch and NoGo tasks - but not in the Oddball task - and corresponded with enhanced fronto-centrally distributed early cue-locked P3 activity (peak latency 325-375 ms post-cue onset at the vertex). In turn, behavioral switch costs were associated with larger late cue-locked P3 amplitudes in the Switch task only (peak latency 400-450 ms post-cue onset at mid-parietal sites). Together with our information theoretical estimations, ERP results suggested that restart and switch costs indexed two neural mechanisms related to the preparatory resolution of uncertainty: (1) the intermittent re-activation of task-set information, and (2) the updating of stimulus-response mappings within an active task set, as indexed by early and late cue-locked P3 activations, respectively. In contrast, target-locked P3 activations reflected a functionally distinct mechanism related to the implementation of task-set information. We conclude that task-switching costs consist of both switch-specific and switch-unspecific processes during the preparation and execution stages of task performance. © 2008 Barceló, Periáñez and Nyhus.