134 resultados para Concurrent object- oriented Petri nets (CO-OPN)
Resumo:
This study aimed to quantify the efficiency and smoothness of voluntary movement in Huntington's disease (HD) by the use of a graphics tablet that permits analysis of movement profiles. In particular, we aimed to ascertain whether a concurrent task (digit span) would affect the kinematics of goal-directed movements. Twelve patients with HD and their matched controls performed 12 vertical zig-zag movements, with both left and right hands (with and without the concurrent task), to large or small circular targets over long or short extents. The concurrent task was associated with shorter movement times and reduced right-hand superiority. Patients with HD were overall slower, especially with long strokes, and had similar peak velocities for both small and large targets, so that controls could better accommodate differences in target size. Patients with HD spent more time decelerating, especially with small targets, whereas controls allocated more nearly equal proportions of time to the acceleration and deceleration phases of movement, especially with large targets. Short strokes were generally less force inefficient than were long strokes, especially so for either hand in either group in the absence of the concurrent task, and for the right hand in its presence. With the concurrent task, however, the left hand's behavior changed differentially for the two groups; for patients with HD, it became more force efficient with short strokes and even less efficient with long strokes, whereas for controls, it became more efficient with long strokes. Controls may be able to divert attention away from the inferior left hand, increasing its automaticity, whereas patients with HD, because of disease, may be forced to engage even further online visual control under the demands of a concurrent task. Patients with HD may perhaps become increasingly reliant on terminal visual guidance, which indicates an impairment in constructing and refining an internal representation of the movement necessary for its. effective execution. Basal ganglia dysfunction may impair the ability to use internally generated cues to guide movement.
Resumo:
The Edinburgh-Cape Blue Object Survey is a major survey to discover blue stellar objects brighter than B similar to 18 in the southern sky. It is planned to cover an area of sky of 10 000 deg(2) with \b\ > 30 degrees and delta < 0 degrees. The blue stellar objects are selected by automatic techniques from U and B pairs of UK Schmidt Telescope plates scanned with the COSMOS measuring machine. Follow-up photometry and spectroscopy are being obtained with the SAAO telescopes to classify objects brighter than B = 16.5. This paper describes the survey, the techniques used to extract the blue stellar objects, the photometric methods and accuracy, the spectroscopic classification, and the limits and completeness of the survey.
Resumo:
0Nuclear magnetic resonance (n.m.r.) imaging was used to study the ingress of water into poly(tetrahydrofurfuryl methacrylate-co-hydroxyethyl methacrylate). The study offers strong evidence that the diffusion is Fickian in nature. The diffusion coefficient, D, obtained by fitting the underlying diffusion profile, attainable from the images, according to the equation for Fickian diffusion, is 1.5 x 10(-11) m(2) s(-1), which is in good correlation with the value of 2.1 x 10(-11) m(2) s(-1), obtained from mass uptake measurements. Additionally, from the T-2-weighted images, Superimposed features observed in addition to the underlying Fickian diffusion profiles were shown to have a longer spin-spin relaxation time, T-2. This Suggests the presence of two types of water within the polymer matrix; a less mobile phase of absorbed water that is interacting strongly with the polymer matrix and a more mobile phase of absorbed water residing within the cracks observed in the environmental scanning electron micrograph. (C) 1997 Elsevier Science Ltd.
