Trenti E.J.,National University of Salta |
Barraza J.F.,Facet Inc |
Barraza J.F.,CONICET |
Eckstein M.P.,University of California at Santa Barbara
Vision Research | Year: 2010
We used the optimal perceptual learning paradigm (Eckstein, Abbey, Pham, & Shimozaki, 2004) to investigate the dynamics of human rapid learning processes in motion discrimination tasks and compare it to an optimal Bayesian learner. This paradigm consists of blocks of few trials defined by a set of target attributes, and it has been shown its ability to detect learning effects appearing as soon as after the first trial. In the present task a sequence consisting of four patches containing random-dot patterns is presented at four separate locations equidistant from a fixation point. On each trial, the random dots in three patches moved with a mean speed and the fourth, target patch, could move either with slower or faster mean speed. Observers' task was to indicate what speed, faster or slower, was present in the display. The mean direction of the target patch was kept invariant along a block of trials. Observers learned the target relevant motion direction through indirect feedback, leading to an improvement in speed identification performance ranging from 15% to 30% which is greater than previously studied contrast defined targets and faces. However, comparison to an ideal learner revealed incomplete or partial learning for the motion task which was lower than previously measured for contrast defined targets and faces. A sub-optimal model that included inefficiencies in the updating of motion direction weights due to memory effects could account for the human learning. Finally, the similarity of the rapid learning effect observed here for motion perception with that found for contrast defined targets for localization and identification tasks could be suggesting a general strategy for learning in the human visual system and some common limitations such as memory. © 2009 Elsevier Ltd. Source
Berry S.A.,University of Minnesota |
Brown C.,National PKU Alliance |
Grant M.,Drexel University |
Greene C.L.,University of Maryland, Baltimore |
And 6 more authors.
Genetics in Medicine | Year: 2013
Fifty years after the implementation of universal newborn screening programs for phenylketonuria, the first disease identified through newborn screening and considered a success story of newborn screening, a cohort of adults with phenylketonuria treated from birth provides valuable information about effects of long-term treatment for inborn errors of metabolism in general, and phenylketonuria specifically. For phenylketonuria, newborn screening allows early implementation of the phenylalanine-restricted diet, eliminating the severe neurocognitive and neuromotor impairment associated with untreated phenylketonuria. However, executive function impairments and psychiatric problems are frequently reported even for those treated early and continuously with the phenylalanine-restricted diet alone. Moreover, a large percentage of adults with phenylketonuria are reported as lost to follow-up by metabolic clinics. While a group of experts identified by the National Institutes of Health convenes to update treatment guidelines for phenylketonuria, we explore individual patient, social, and economic factors preventing >70% of adult phenylketonuria patients in the United States from accessing treatment. As more conditions are identified through newborn screening, factors affecting access to treatment grow in importance, and we must continue to be vigilant in assessing and addressing factors that affect patient treatment outcomes and not just celebrate amelioration of the most severe manifestations of disease. © American College of Medical Genetics and Genomics. Source
Facet Inc | Date: 2013-09-20
A fixing arrangement comprises a retaining element and a clamping sleeve which receives a bone screw. The bone screw has a head and a secondary thread and is pivotally mounted in the clamping sleeve. The clamping sleeve has a radially protruding section on the outer casing of the clamping sleeve and at least one track of a clamping thread, which complements the secondary thread, in the interior of the clamping sleeve. In the unclamped state, a free path is formed by a clearance on the clamping sleeve. A protruding section engages into an opening on the receiving seat in a formfitting manner, and the thickened section is shaped to expand towards the rear in the form of a cone. The cone angle is selected such that the free path divided by the tangent of the half-cone angle corresponds to 0.5 to 2.5 times the thread pitch of the secondary thread.
Facet Inc | Date: 2013-03-28
A reinforcement implant comprises a cantilever part for spanning a resected area of a lamina and an anchoring part at opposite ends of the cantilever part. The first anchoring part has a pressure surface for bearing on the spinous process of the vertebra, and the second anchoring part has a transverse thrust surface for bearing on an outer face of the lamina. The pressure surface and the transverse thrust surface enclose an obtuse angle. An anti-shear device (e.g., a facet screw) is arranged on the transverse thrust surface, and one edge of the transverse thrust surface is adjoined by a load-bearing area of the cantilever part. The implant can thus be mounted in place from outside without needing to be pushed with a load-bearing action into the resected area. The resection surfaces on the lamina are free of loads, such that unevenness does not cause problems.
Facet Inc | Date: 2013-12-16
The invention relates to an intervertebral fusion implant for fusing two adjacent vertebrae, comprising an adjustable support body, the base surface and cover surface of which are configured to bear on end plates of the adjacent vertebrae, wherein provision is made for a side bracket, which can be pivoted laterally about a hinge and the base and cover of which have a planar design, and provision is made for an actuator for pivoting out the side bracket into a position (working position) spread from the support body. As a result, the implant has particularly small dimensions and can, after assembly at the envisaged implantation site, be actuated in such a way that it becomes larger and thereby affords a larger support surface for support in the intervertebral space. Thus, even comparatively large-area defects can be treated by minimally invasive surgery.