In this paper we propose a new recursive algorithm for computing the staircase form of a matrix pencil, and implicitly its Kronecker structure. The algorithm compares favorably to existing ones in terms of elegance, versatility, and complexity. In particular, the algorithm without any modiication yields the structural invari-ants associated with a generalized state{space system and its system p...

Most of the studies on gender differences in spatial abilities have focused on traditional paper and pencil cognitive tests, while these differences have been less investigated in navigational tasks carried out in complex virtual environments (VEs). The aim of the present study has been to evaluate gender differences in route and survey knowledge by means of specific tasks (route-learning, poin...

A mixed matrix pencil is a matrix pencil which has two kinds of nonzero coefficients: fixed constants that account for conservation laws and independent parameters that represent physical characteristics. In this paper, we characterize the indices of nilpotency of the Kronecker canonical form for a mixed matrix pencil in terms of matroids. As a byproduct, we provide an algorithm for computing t...

abstract The theory of eigenvalues and eigenvectors of rectangular matrix pencils is complicated by the fact that arbitrarily small perturbations of the pencil can cause them disappear. However, there are applications in which the properties of the pencil ensure the existence of eigen-values and eigenvectors. In this paper it is shown how to develop a perturbation theory for such pencils. ABSTR...

BACKGROUND Spatial neglect affects perception along different dimensions. However, there is limited availability of 3-dimensional (3D) methods that fully map out a patient's volume of deficit, although this could guide clinical management. OBJECTIVE To test whether patients with neglect exhibit simple contralesional versus complex perceptual deficits and whether deficits are best described us...

BACKGROUND The postoperative cognitive function is impaired in elderly patients after general anaesthesia. The fast recovery after xenon anaesthesia was hypothesized to be advantageous in this scenario. We compared early postoperative cognitive function after xenon and sevoflurane anaesthesia in this study. METHODS The study was approved by the local ethics committee and written informed cons...

This paper proposes an extension to the existing automatic pencil drawing generation technique based on Line Integral Convolution (LIC). The original LIC pencil filter utilizes image segmentation and texture direction detection techniques for defining outlines and stroke directions, and the quality of a resulting image depends largely on the result of the white noises and the texture directions...

BACKGROUND AND PURPOSE The present study investigated the lesion anatomy of anosognosia for visuospatial neglect resulting from right hemispheric stroke. METHODS In 63 patients, self-ratings of performance in paper-and-pencil tests were contrasted with external performance ratings. Lesion analysis was conducted on patient subgroups with different degrees of anosognosia but comparable visuospa...

Processing speed is often described as a fundamental resource determining individual (e.g., I.Q.) and group (e.g., developmental) differences in cognition. However, most tests that measure speed present many items on a single page. Because many groups with slowed responding are also distractible, we compared younger and older adults on high(i.e., standard) versus low-distraction versions of two...