Seismocardiographic Signal Timing with Myocardial Strain

Speckle Tracking Echocardiography (STE) is a relatively new method for cardiac function evaluation. In the current study, STE was used to investigate the timing of heart-induced mostly subaudible (i.e., below the frequency limit of human hearing) chest-wall vibrations in relation to the longitudinal myocardial strain. Such an approach may help elucidate the genesis of these vibrations, thereby improving their diagnostic value

Nonlocality of Accelerated Systems

The conceptual basis for the nonlocality of accelerated systems is presented. The nonlocal theory of accelerated observers and its consequences are briefly described. Nonlocal field equations are developed for the case of the electrodynamics of linearly accelerated systems.Comment: LaTeX file, no figures, 9 pages, to appear in: "Black Holes, Gravitational Waves and Cosmology" (World Scientific, Singapore, 2003

Segmentation of complex outdoor scenes

Journal ArticleA new simpler approach to image segmentation via recursive region splitting and merging is presented. Unlike other techniques the kernel of splitting is based on a generalization of a two class gradient relaxation method and merging uses a statistical analysis of variance

Band gap engineering in simultaneous phononic and photonic crystal slabs

We discuss the simultaneous existence of phononic and photonic band gaps in two types of phononic crystals slabs, namely periodic arrays of nanoholes in a Si membrane and of Si nanodots on a SiO2 membrane. In the former geometry, we investigate in detail both the boron nitride lattice and the square lattice with two atoms per unit cell (these include the square, triangular and honeycomb lattices as particular cases). In the latter geometry, some preliminary results are reported for a square lattice

Limitations of Radar Coordinates

The construction of a radar coordinate system about the world line of an observer is discussed. Radar coordinates for a hyperbolic observer as well as a uniformly rotating observer are described in detail. The utility of the notion of radar distance and the admissibility of radar coordinates are investigated. Our results provide a critical assessment of the physical significance of radar coordinates.Comment: 12 pages, revtex and pictex macros, 3 pictex figures, 1 eps figure. Expanded versio