Magic echo cycles are introduced for performing quadrupolar echo spectroscopy of spin-1 nuclei. An analysis is performed via average Hamiltonian theory showing that the evolution under chemical shift or static field inhomogeneity can be refocused simultaneously with the quadrupolar interaction using these cycles. Due to the higher convergence in the Magnus expansion, with sufficient RF power, m...

Echo-enhanced ultrasound is a newly available imaging modality for the evaluation of pancreatic lesions. Neoplasms of the pancreas tend to have a characteristic vascularization pattern. Adenocarcinomas are often hypovascularized as compared to the surrounding tissue. On the other hand, neuroendocrine tumors are hypervascularized lesions. Masses associated with pancreatitis have a different vasc...

As in vision, acoustic signals can be reflected by a smooth surface creating an acoustic mirror image. Water bodies represent the only naturally occurring horizontal and acoustically smooth surfaces. Echolocating bats flying over smooth water bodies encounter echo-acoustic mirror images of objects above the surface. Here, we combined an electrophysiological approach with a behavioral experiment...

Multivariate pattern analysis is often assumed to rely on signals that directly reflect differences in the distribution of particular neural populations. The source of the signal used in these analyses remains unclear however, and an alternative model suggests that signal from larger draining veins may play a significant role. The current study was designed to investigate the vascular contribut...

The work is devoted to the investigation of the key concepts of mathematical theory of pattern recognition: image equivalence and invariance. Different ways to determine equivalence on the image set are considered and relations between image equivalence and invariance are analyzed. It is proved that the image recognition task in standard formulation can be reduced to the task that has a correct...

A series of psychoacoustic experiments were carried out to explore the relationship between an objective measure of reverberation echo density, called the normalized echo density (NED), and subjective perception of the time-domain texture of reverberation. In one experiment, 25 subjects evaluated the dissimilarity of signals having static echo densities. The reported dissimilarities matched abs...