The Born approximation is based on the assumption of small slowness perturbation. We investigate the limits of the Born approximation when applied to wave-equation migration velocity analysis and propose two new schemes which allow for larger slowness anomalies, while improving accuracy and increasing stability. The new schemes are based on linearizations of exponential functions using bilinear...

Obsessive slowness is described to be a syndrome of extreme slowness in ways various tasks are performed. Its existence as an independent syndrome is challenged by authors, who regard it to be a part of obsessive compulsive disorder. Behavioural techniques of prompting, pacing and shaping are recommended for treatment of this condition. We describe here a case of a 21 year old male patient who ...

In the seismic tomography problem, the subsurface slowness distribution is estimated from the travel-times computed along generally curved rays. For a dense and uniform set of rays, the slowness distribution will be correctly reconstructed. However, for an uneven distribution of rays, the estimated slowness distribution may be influenced by the ray configuration. For the linear case, the seismi...

Slowness in obsessive-compulsive disorder (OCD) has been attributed to intrusive thoughts or meticulousness. Recent research suggests that slowness in OCD may be particularly evident on tests of executive function subserved by frontostriatal circuitry. In the present study, the speed and accuracy of responding on neuropsychological tests of executive functions and psychomotor speed were investi...

A comprehensive investigation of nerve motor conduction velocity was carried out in the ulnar nerve of 70 patients in the chronic stage of Chagas disease. It was found that 2.6% of them, had slowness of the large motor axons at distal segments and 14% at proximal segments. Twenty seven percent of them had also slowness of conduction at the smallest motor fibers. These observations signal that s...

Recently, a noncentrosymmetric crystal, KNaNbOF₅, has attracted attention due to its potential to present piezoelectric properties. Although α- and β-KNaNbOF₅ are similar in their stoichiometries, their structural frameworks, and their synthetic routes, the two phases exhibit very different properties. This paper presents, from first-principles calculations, comparative studies of the structura...