Concise and numerically feasible dynamic and static Green's functions are obtained in dyadic form by solving the wave equation and the equilibrium equation with general source distribution in transversely isotropic (TI) media. The wave and equilibrium equations are solved by using an extended version of the Kupradze method originally developed for isotropic media. The dynamic Green's function i...

The separation of wave-modes for isotropic elastic wavefields is typically done using Helmholtz decomposition. However, Helmholtz decomposition using conventional divergence and curl operators in anisotropic media only partially separates the elastic wave-modes. The separation of anisotropic wavefields requires operators which depend on local material parameters. Wavefield separation operators ...

The paper discuses the effect of initial stresses on the reflection coefficients of plane waves in a dissipative medium. Basic governing equations are formulated in context of Biot's incremental deformation theory. These governing equations are solved analytically to obtain the dimensional phase velocities of plane waves propagating in plane of symmetry. Closed-form expressions for the reflecti...

BACKGROUND Several new techniques exist for measuring arterial stiffness, but their association with central pulse wave velocity (PWV), an established measure of central arterial stiffness, has not been compared in the same study. The aim of this study was to compare the agreement of the new techniques with central PWV. METHODS Fifteen men with coronary artery disease (59 +/- 2 years of age) ...

OBJECTIVE The purpose of this study is to determine if crawling wave elastography, a novel sonoelastography technique, can be used to provide quantitative measurements of thyroid tissue shear velocity (a measure of tissue stiffness) and distinguish between benign and malignant thyroid nodules. STUDY DESIGN Diagnostic test assessment. SETTING Academic university. SUBJECTS AND METHODS Fresh...

The wavefields generated by monopole and dipole sources in a fluid filled borehole embedded in multilayered transversely isotropic saturated porous formations are studied. The layers are modeled following Biot theory modified in accordance with homogenization theory. It allows to take into account a transversely isotropic skeleton and/or a transversely isotropic complex permeability tensor. The...

Heart period variability (HPV) metrics have been suggested for use in medical monitoring of trauma patients. This study sought to ascertain the use of various HPV metrics in tracking central blood volume during simulated hemorrhage in individual humans. One hundred one healthy nonsmoking volunteers (58 men, 43 women) were instrumented for continuous measurement of electrocardiogram and beat-by-...

Perioperative goal directed therapy (GDT) based on measurement of stroke volume (SV) is expected to improve postoperative outcome1). A device that can accurately measure stroke volume (SV) during surgery and that is both minimally-invasive and low cost is ideal. Many methods have been developed to measure SV less-invasively and continuously; pulse contour and intrathoracic impedance methods hav...

Objectives: Previous animal and human experiments have suggested that reduction in central blood volume either increases or decreases the amplitude of R waves in various electrocardiograph (ECG) leads depending on underlying pathophysiology. In this investigation, we used graded central hypovolemia in adult volunteer subjects to test the hypothesis that moderate reductions in central blood volu...

[1] We present DR2012, a global SV-wave tomographic model of the upper mantle. We use an extension of the automated waveform inversion approach of Debayle (1999) which improves our mapping of the transition zone with extraction of fundamental and higher-mode information. The new approach is fully automated and has been successfully used to match approximately 375,000 Rayleigh waveforms. For eac...