scholarly journals Spectral Observations of Filament Activation

2013 ◽  
Vol 8 (S300) ◽  
pp. 447-448 ◽  
Author(s):  
G. Mashnich
Keyword(s):  
Spectral Data ◽  
Northern Hemisphere ◽  
Doppler Velocity ◽  
Velocity Measurements ◽  
Solar Filament ◽  
Filament Activation ◽  
Solar Uv ◽  
Intensity Fluctuations ◽  
Quiescent Filament

AbstractStudies of solar filament (prominence) activation and eruption are often based on measurements of intensity fluctuations in various solar emission bands and rarely on Doppler velocity measurements. The goal of this paper is to analyze the process of quiescent filament activation, using spectral data, and its associated events in solar UV band. Motions have been examined in a small southern fragment of a quiescent, extended filament in the northern hemisphere prior to and during its activation on June 14 2012. A part of the fragment disappeared after the filament activation.

Instantaneous diastolic transmitral pressure differences from color Doppler M mode echocardiography

1996 ◽  
Vol 271 (4) ◽  
pp. H1267-H1276 ◽  
Author(s):  
N. L. Greenberg ◽  
P. M. Vandervoort ◽  
J. D. Thomas
Keyword(s):  
Pressure Difference ◽  
Continuous Wave ◽  
Color Doppler ◽  
Digital Processing ◽  
Left Ventricular ◽  
Filling Pressure ◽  
Diastolic Filling ◽  
Doppler Velocity ◽  
Inertial Forces ◽  
Velocity Measurements

Pulsed and continuous wave Doppler velocity measurements are routinely used in clinical practice to assess severity of stenotic and regurgitant valves or to estimate intracavitary pressures. However, this method only evaluates the convective component of the pressure gradient (based on the velocity measurements) and neglects the contribution of inertial forces that can be important, in particular for flow across nonstenotic valves. Digital processing of color Doppler ultrasound data was used to noninvasively estimate both the convective and inertial components of the transmitral pressure difference. Simultaneous pressure and velocity measurements were obtained in six anesthetized open-chest dogs. The instantaneous diastolic transmitral pressure difference is computed from the M mode spatiotemporal velocity distribution using the unsteady flow form of the Bernoulli equation. The inclusion of the inertial forces ([delta PI]max = 0.90 +/- 0.30 mmHg) in the noninvasive pressure difference calculation significantly increased the correlation with catheter-based measurement (r = 0.15 +/- 0.23 vs. 0.85 +/- 0.08; P < 0.0001) and also allowed an accurate approximation of the peak early filling pressure difference ([delta PC+I]max = 0.95[delta Pcath]max + 0.07, r = 0.92, P < 0.001, error: epsilon C+I ([delta PC+I]max-[delta Pcath]max) = 0.01 +/- 0.24 mmHg, N = 90]. Noninvasive estimation of left ventricular filling pressure differences using this technique will improve the understanding of diastolic filling and function of the heart.

scholarly journals Operational Multiple-Doppler Wind Retrieval Inferred from Long-Range Radial Velocity Measurements

2008 ◽  
Vol 47 (11) ◽  
pp. 2929-2945 ◽  
Author(s):  
Olivier Bousquet ◽  
Pierre Tabary ◽  
Jacques Parent du Châtelet
Keyword(s):  
Radial Velocity ◽  
Doppler Velocity ◽  
Velocity Measurements ◽  
Wind Fields ◽  
Pulse Rise Time ◽  
Wind Retrieval ◽  
Radar Network ◽  
Precipitation Regimes ◽  
Operational Networks ◽  
Scanning Strategies

Abstract The recent deployment of an innovative triple pulse rise time (PRT) scheme within the French operational radar network allows for the simultaneous collection of reflectivity and radial velocity measurements up to a range of 250 km with no ambiguity. This achievement brings new perspectives in terms of operational exploitation of Doppler measurements including the capability to consistently perform multiple-Doppler wind synthesis in a fully operational framework. Using real and simulated Doppler observations, the authors show that the 3D wind fields retrieved in that framework can definitely be relied upon to achieve a consistent and detailed mapping of the airflow structure in various precipitation regimes despite radar baselines averaging ∼180 km and very limited scanning strategies. This achievement could be easily transposed to other operational networks and represents a remarkable opportunity to add further value to operational Doppler velocity measurements.

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