نتایج جستجو برای: velocity change
تعداد نتایج: 723900 فیلتر نتایج به سال:
For regions of partial melt in the lower mantle, both compressional and shear wave velocities decrease monotonically with increasing melt volume fraction. It has been observed that regions close to the core-mantle boundary thought to contain partial melt have a velocity decrement ratio (relative change in shear velocity over relative change of compressional velocity) of about 3. This is certain...
We analyse the helical motion of organisms, concentrating on the means by which organisms change the direction in space of the axis of the helical trajectory, which is the net direction of motion. We demonstrate that the direction of the axis is determined largely by the direction of the organism's rotational velocity. Changes in direction of the rotational velocity, with respect to the organis...
1 The Problem of Instantaneous Rates of Change The concept of the instantaneous rate of change of some physical quantity, position most strikingly, poses a significant philosophical dilemma. Notoriously, Zeno argued, in his arrow paradox, that the very concept of an instantaneous rate of change in position is both unavoidable in the explanation of motion and incoherent. Recently worries about i...
We extend time-domain velocity continuation to the zero-offset 3D azimuthally anisotropic case. Velocity continuation describes how a seismic image changes given a change in migration velocity. This description turns out to be of a wave propagation process, in which images change along a velocity axis. In the anisotropic case, the velocity model is multi-parameter. Therefore, anisotropic image ...
PURPOSE The purpose of this study was to investigate the relationship between phoria and the dynamics of vergence eye movements as described by the ratio of convergence average peak velocity to divergence average peak velocity, termed the vergence peak velocity ratio. METHODS Phoria and vergence step responses were recorded. Three measures of phoria were assessed: baseline phoria, which is th...
OBJECTIVES To determine if echocardiographic measurements change at a greater rate in dogs with myxomatous mitral valve disease (MMVD) that die of cardiac mortality. ANIMALS Client-owned dogs (n = 242) with MMVD of varying severity were recruited from first opinion private practice. Only dogs which died during the study period (n = 102) were included in statistical analyses. METHODS Prospec...
in recent years several studies have been done in the field of laminar flame speed. one of the important characteristics of the combustion is the laminar flame speed. in this study, the effects of co2 and n2 on the laminar flame speed of natural gas and gasoline fuel mixture have been investigated. schlieren method has been used in this study. experiments were carried out at pressure of 1 bar a...
A number of accounts of human auditory perception assume that listeners use prior stimulus context to generate predictions about future stimulation. Here, we tested an auditory pitch-motion hypothesis that was developed from this perspective. Listeners judged either the time change (i.e., duration) or pitch change of a comparison frequency glide relative to a standard (referent) glide. Under a ...
BACKGROUND Percutaneous coronary intervention (PCI) aims to increase coronary blood flow by relieving epicardial obstruction. However, no study has objectively confirmed this and assessed changes in flow over different phases of the cardiac cycle. We quantified the change in resting and hyperemic flow velocity after PCI in stenoses defined physiologically by fractional flow reserve and other pa...
An object moving in depth produces retinal images that change in position over time by different amounts in the two eyes. This allows stereoscopic perception of motion in depth to be based on either one or both of two different visual signals: inter-ocular velocity differences, and binocular disparity change over time. Disparity change over time can produce the perception of motion in depth. Ho...
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