scholarly journals An efficient tracer test for time-variable transit time distributions in periodic hydrodynamic systems

2014 ◽  
Vol 41 (5) ◽  
pp. 1567-1575 ◽  
Author(s):  
Ciaran J. Harman ◽  
Minseok Kim
Keyword(s):  
Transit Time ◽  
Tracer Test ◽  
Time Variable ◽  
Hydrodynamic Systems

scholarly journals Time‐Variable Transit Time Distributions in the Hyporheic Zone of a Headwater Mountain Stream

2018 ◽  
Vol 54 (3) ◽  
pp. 2017-2036 ◽  
Author(s):  
Adam S. Ward ◽  
Noah M. Schmadel ◽  
Steven M. Wondzell
Keyword(s):  
Transit Time ◽  
Hyporheic Zone ◽  
Time Variable ◽  
Mountain Stream

Saturn's E, G and F rings: modulated by the plasma sheet

1984 ◽  
Vol 75 ◽  
pp. 597
Author(s):  
E. Grün ◽  
G.E. Morfill ◽  
T.V. Johnson ◽  
G.H. Schwehm
Keyword(s):  
Solar Wind ◽  
Direct Contact ◽  
Transport Processes ◽  
Time Variable ◽  
Dust Particles ◽  
Spatial Diffusion ◽  
Drag Forces ◽  
Orbit Perturbation ◽  
Time Variations ◽  
F Ring

ABSTRACTSaturn's broad E ring, the narrow G ring and the structured and apparently time variable F ring(s), contain many micron and sub-micron sized particles, which make up the “visible” component. These rings (or ring systems) are in direct contact with magnetospheric plasma. Fluctuations in the plasma density and/or mean energy, due to magnetospheric and solar wind processes, may induce stochastic charge variations on the dust particles, which in turn lead to an orbit perturbation and spatial diffusion. It is suggested that the extent of the E ring and the braided, kinky structure of certain portions of the F rings as well as possible time variations are a result of plasma induced electromagnetic perturbations and drag forces. The G ring, in this scenario, requires some form of shepherding and should be akin to the F ring in structure. Sputtering of micron-sized dust particles in the E ring by magnetospheric ions yields lifetimes of 102to 104years. This effect as well as the plasma induced transport processes require an active source for the E ring, probably Enceladus.

Cerebral vascular mean transit time determined by PET and DSC-MRI

2005 ◽  
Vol 25 (1_suppl) ◽  
pp. S676-S676
Author(s):  
Masanobu Ibaraki ◽  
Hiroshi Ito ◽  
Eku Shimosegawa ◽  
Hideto Toyoshima ◽  
Keiichi Ishigame ◽  
...  
Keyword(s):  
Transit Time ◽  
Mean Transit Time ◽  
Dsc Mri ◽  
Cerebral Vascular

Transit-time effects in saturated absorption resonances

1986 ◽  
Vol 47 (12) ◽  
pp. 2025-2039 ◽  
Author(s):  
A. Titov ◽  
Yu. Malyshev ◽  
Yu. Rastorguev
Keyword(s):  
Transit Time ◽  
Time Effects ◽  
Saturated Absorption

Correlation of Data Obtained by Radiocardiography and Right-Heart Catheterization in Cardiac Patients

1968 ◽  
Vol 07 (02) ◽  
pp. 125-129
Author(s):  
J. Měštan ◽  
V. Aschenbrenner ◽  
A. Michaljanič
Keyword(s):  
Capillary Pressure ◽  
Transit Time ◽  
Right Heart Catheterization ◽  
Heart Catheterization ◽  
Right Heart ◽  
Pulmonary Capillary ◽  
Filling Time ◽  
Pulmonary Capillary Pressure ◽  
The Mean ◽  
Pulmonary Transit Time

SummaryIn patients with acquired and congenital valvular heart disease correlations of the parameters of the radiocardiographic curve (filling time of the right heart, minimal pulmonary transit time, peak-to-peak pulmonary transit time, and the so-called filling time of the left heart) with the mean pulmonary artery pressure and the mean pulmonary “capillary” pressure were studied. Further, a regression equation was determined by means of which the mean pulmonary “capillary” pressure can be predicted.

Measurement of Renal Parenchymal Transit Time of 99mTc-MAG3 Using Factor Analysis

1990 ◽  
Vol 29 (04) ◽  
pp. 170-176 ◽  
Author(s):  
M. V. Yester ◽  
Eva Dubovsky ◽  
C. D. Russell
Keyword(s):  
Factor Analysis ◽  
Transit Time ◽  
Region Of Interest ◽  
Initial Slope ◽  
Cortical Region ◽  
Time Activity ◽  
Appearance Time ◽  
Activity Curve ◽  
System Factor ◽  
Collecting System

Renal parenchymal transit time of the recently introduced radiopharmaceutical 99mTc-MAG3 (mercaptoacetylglycylglylcylglycinel) was measured in 37 kidneys, using factor analysis to separate parenchymal activity from that in the collecting system. A new factor algorithm was employed, based on prior interpolative background subtraction and use of the fact that the initial slope of the collecting system factor time-activity curve must be zero. The only operator intervention required was selection of a rectangular region enclosing the kidney (by identifying two points at opposite corners). Transit time was calculated from the factor time-activity curves both by deconvolution of the parenchymal factor curve and also by measuring the appearance time for collecting system activity from the collecting system factor curve. There was substantial agreement between the two methods. Factor analysis led to a narrower range of normal values than a conventional cortical region-of-interest method, presumably by decreasing crosstalk from the collecting system. In preliminary trials, the parenchymal transit time did not well separate four obstructed from seventeen unobstructed kidneys, but it successfully (p <0.05) separated six transplanted kidneys with acute rejection or acute tubular necrosis from 10 normal transplants.

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