Use of topological charge to determine filament location and dynamics in a numerical model of scroll wave activity

2002 ◽  
Vol 49 (10) ◽  
pp. 1086-1093 ◽  
Author(s):  
M.-A. Bray ◽  
J.P. Wikswo
Keyword(s):  
Numerical Model ◽  
Topological Charge ◽  
Wave Activity ◽  
Scroll Wave

scholarly journals Stratospheric Vacillations and the Major Warming over Antarctica in 2002

2005 ◽  
Vol 62 (3) ◽  
pp. 629-639 ◽  
Author(s):  
A. A. Scaife ◽  
D. R. Jackson ◽  
R. Swinbank ◽  
N. Butchart ◽  
H. E. Thornton ◽  
...  
Keyword(s):  
Numerical Model ◽  
Model Experiment ◽  
Planetary Wave ◽  
Wave Activity ◽  
Cyclonic Circulation ◽  
Zonal Winds ◽  
Westerly Winds ◽  
Vertical Propagation ◽  
The Antarctic ◽  
Preceding Winter

Abstract The conditions that lead to the major warming over Antarctica in late September 2002 are examined. In many respects, the warming resembled wave-2 warmings seen in the Northern Hemisphere; the winter cyclonic circulation was split into two smaller cyclones by a large amplitude planetary wave disturbance that appeared to propagate upward from the troposphere. However, in addition to this classic warming mechanism, distinctive stratospheric vacillations occurred throughout the preceding winter months. These vacillations in wave amplitude, Eliassen–Palm fluxes, and zonal-mean zonal winds are examined. By comparison with a numerical model experiment, it is shown that the vacillation is accompanied by a systematic weakening of the westerly winds over the season. This preconditions the Antarctic circulation, and it is argued that it allows anomalously strong vertical propagation of planetary waves from the troposphere into the stratosphere. By contrast, a survey of previous winters shows that stratospheric westerlies usually vary much more gradually, with vacillations only occurring for short periods of time, if at all, in a given winter. Similar vacillations in a numerical model of the stratosphere only occur if the forcing amplitude is above a certain value. However, the level of winter-mean wave activity entering the stratosphere during 2002 is not unprecedented, and there is still some uncertainty over the cause of the onset and persistence of the vacillation and, ultimately, the major warming.

Sa1640 NONINVASIVE MEASUREMENT OF SMALL BOWEL SLOW WAVE ACTIVITY IN NEONATES - A PILOT STUDY

2020 ◽  
Vol 158 (6) ◽  
pp. S-364
Author(s):  
Suseela Somarajan ◽  
Nicole D. Muszynski ◽  
Aurelia s. Monk ◽  
Joseph D. Olson ◽  
Alexandra Russell ◽  
...  
Keyword(s):  
Pilot Study ◽  
Small Bowel ◽  
Slow Wave ◽  
Wave Activity ◽  
Slow Wave Activity ◽  
Noninvasive Measurement

Slow Wave Activity Related to Working Memory Maintenance in the N-Back Task

2016 ◽  
Vol 30 (4) ◽  
pp. 141-154 ◽  
Author(s):  
Kira Bailey ◽  
Gregory Mlynarczyk ◽  
Robert West
Keyword(s):  
Working Memory ◽  
Slow Wave ◽  
Time Course ◽  
Relevant Information ◽  
Wave Activity ◽  
Slow Wave Activity ◽  
Response Accuracy ◽  
Functional Neuroanatomy ◽  
Stimulus Interval ◽  
Back Task

Abstract. Working memory supports our ability to maintain goal-relevant information that guides cognition in the face of distraction or competing tasks. The N-back task has been widely used in cognitive neuroscience to examine the functional neuroanatomy of working memory. Fewer studies have capitalized on the temporal resolution of event-related brain potentials (ERPs) to examine the time course of neural activity in the N-back task. The primary goal of the current study was to characterize slow wave activity observed in the response-to-stimulus interval in the N-back task that may be related to maintenance of information between trials in the task. In three experiments, we examined the effects of N-back load, interference, and response accuracy on the amplitude of the P3b following stimulus onset and slow wave activity elicited in the response-to-stimulus interval. Consistent with previous research, the amplitude of the P3b decreased as N-back load increased. Slow wave activity over the frontal and posterior regions of the scalp was sensitive to N-back load and was insensitive to interference or response accuracy. Together these findings lead to the suggestion that slow wave activity observed in the response-to-stimulus interval is related to the maintenance of information between trials in the 1-back task.

NUMERICAL MODEL TO SIMULATE THE EROSION ON THE SLOPE DUE TO OVERTOPPING

2010 ◽  
Vol 13 (3) ◽  
pp. 78-87
Author(s):  
Hoai Cong Huynh
Keyword(s):  
Numerical Model ◽  
Flow Model ◽  
Bed Load ◽  
Experiment Data ◽  
Step Method ◽  
Morphological Model ◽  
Load Transport ◽  
Bed Load Transport ◽  
The Finite Difference Method ◽  
Good Agreement

The numerical model is developed consisting of a 1D flow model and the morphological model to simulate the erosion due to the water overtopping. The step method is applied to solve the water surface on the slope and the finite difference method of the modified Lax Scheme is applied for bed change equation. The Meyer-Peter and Muller formulae is used to determine the bed load transport rate. The model is calibrated and verified based on the data in experiment. It is found that the computed results and experiment data are good agreement.

A numerical model to verify the communication between Gari and Peccia springs (Cassino, Central Italy)

2015 ◽  
Vol 35 ◽  
pp. 268-271
Author(s):  
Michele Saroli ◽  
Michele Lancia ◽  
Marco Petitta ◽  
Gabriele Scarascia Mugnozza
Keyword(s):  
Numerical Model ◽  
Central Italy
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