From the photometric results presented in this communication it appears that contrary to some earlier indications the open spirals, with their supergiant stars and superficial structure of spiral arms, are not appreciably larger than spheroidal galaxies, which seem to be devoid of highly luminous stars and free of distributional irregularities. It follows that if in the course of time spiral ar...

The goal is to perform geometric studies on cone-beam CT scanning along a three-dimensional (3D) spiral of variable radius. First, the background for variable radius spiral cone-beam scanning is given in the context of electron-beam CT/micro-CT. Then, necessary and sufficient conditions are proved for existence and uniqueness of PI lines inside the variable radius 3D spiral. These results are n...

Atrial fibrillation (AF) is believed to be perpetuated by recirculating spiral waves. Atrial structures are often characterized with action potentials of varying morphologies; however, the role of the structure-dependent atrial electrophysiological heterogeneity in spiral wave behaviour is not well understood. The purpose of this study is to determine the effect of action potential morphology h...

the problem of the hermeneutical circle is one of the contentious issues in philosophical hermeneutics. this paper, begins with focusing on the question as to whether what hermeneuts mean by a hermeneutical circle is in fact a real circle with no analogical sense involved. recognizing that this problem is not confined to the relation between part and whole, this study confines itself to explore...

Acquisitions with the spiral-in/out technique result in two separate image timeseries obtained during the spiral-in and spiral-out trajectory. In uniform brain regions the two components have comparable signal and BOLD contrast and can be averaged, but in regions compromised by susceptibility effects where both signal and noise can differ in the two images other combination methods may be more ...

One of the most growing areas in the embedded community is multimedia devices. Multimedia devices incorporate a number of complicated functions for their operation, like motion estimation. A multitude of different implementations have been proposed to reduce motion estimation complexity, such as spiral search. We have studied the implementations of spiral search and identified areas of improvem...

We study spiral waves in a model of Ca dynamics in the Xenopus laevis oocyte. Spiral waves in the model were initiated by simulating the release of inositol 1,4,5-trisphosphate (IP3), a common experimental protocol. No artificial heterogeneities need to be imposed on the system for the spontaneous formation of spiral waves. Increasing the size of the IP3 additions caused a decrease in the rotat...

SPIRAL is an autotuning, program generation and code synthesis system that offers a fully automatic generation of highly optimized target codes, customized for the specific execution platform at hand. Initially, SPIRAL was targeted at problem domains in digital signal processing, later also at basic linear algebra. We open SPIRAL up to a new, practically relevant and challenging domain: multigr...

Motivated by recent observations which detect dust at large galactocentric distances in the disks of spiral galaxies, we propose a mechanism of outward radial transport of dust by spiral stellar density waves. We consider spiral galaxies in which most of dust formation is localized inside the corotation radius. We show that in the disks of such spiral galaxies, the dust grains can travel over r...

Design, development and testing of transducers for creating spiral waves for underwater navigation The use of spiral waves for underwater acoustic navigation has received much attention in recent years. A spiral wave is characterized as a diverging wavefront that is omnidirectional by magnitude but with a phase that varies linearly by azimuthal angle. Such a signal may be exploited in underwate...