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Fixation disparity

John T McElveen, J Walter Kutz
Controversies have been associated with the etiology, diagnosis, evaluation, and management of otosclerosis since Valsalva first described stapes fixation as a cause of hearing loss. Although the exact mechanism of the bone remodeling associated with otosclerosis remains uncertain, stapedotomy has been accepted as the surgical treatment of most patients with stapedial otosclerosis. There remains a disparity of opinion, however, regarding the role of preoperative imaging, surgical technique, implant selection, and medical therapy for cochlear otosclerosis...
April 2018: Otolaryngologic Clinics of North America
Martin C Jordan, Konrad Fuchs, Timo M Heintel, Hendrik Jansen, Stefanie Hoelscher-Doht, Rainer H Meffert
PURPOSE: To compare fixed- or variable-angle locking screws in calcaneal fracture plates using a sawbones biomechanical model. METHODS: Intra-articular calcaneal fractures were created in synthetic bones. Reduction and stabilization was performed with three different plates. In Group A, a fixed-angle locking plate was used with screws fastened perpendicularly to the plate (3.5 LCP, DePuySynthes). In Groups B and C (2.7 VA-LCP, DePuySynthes and 3.5 Aptus, Medartis, respectively), fracture fixation was performed using variable-angle locking plates...
February 9, 2018: Journal of Orthopaedic Trauma
Selam W Habtegiorgis, Katharina Rifai, Siegfried Wahl
Spatially varying distortions in optical elements-for instance prisms and progressive power lenses-modulate the visual world disparately in different visual areas. Saccadic eye movements in such a complexly distorted environment thereby continuously alter the retinal location of the distortions. Yet the visual system achieves perceptual constancy by compensating for distortions irrespective of their retinal relocations at different fixations. Here, we assessed whether the visual system retains its plasticity to distortions across saccades to attain stability...
January 1, 2018: Journal of Vision
Christopher R Friesen, Rasmus Johansson, Mats Olsson
Polymorphism has fascinated biologists for over a century because morphs persist within populations through evolutionary time in spite of showing disparate behavioral and physiological phenotypes; any one morph should go to fixation with the slightest fitness advantage over the others. Surely there must be trade-offs that balance selection on them. The polychromatic morphs of the Australian painted dragon lizard, Ctenophorus pictus, are one such system. The male color morphs of painted dragons have different physiological and behavioral traits including reproductive tactics, hormone levels, and the rate of body condition loss through the reproductive season...
August 2017: Journal of Experimental Zoology. Part A, Ecological and Integrative Physiology
Anna Przekoracka-Krawczyk, Alicja Brenk-Krakowska, Pawel Nawrot, Patrycja Rusiak, Ryszard Naskrecki
Purpose: Individuals with developmental dyslexia suffer not only from reading problems as more general motor deficits can also be observed in this patient group. Both psychometric clinical tests and objective eyetracking methods suggest that unstable binocular fixation may contribute to reading problems. Because binocular instability may cause poor eye-hand coordination and impair motor control, the primary aim of this study was to explore in dyslexic subjects the influence of unstable binocular fixation on reaction times (RTs) and implicit motor learning (IML), which is one of the fundamental cerebellar functions...
December 1, 2017: Investigative Ophthalmology & Visual Science
Moritz Crönlein, Martin Lucke, Marc Beirer, Dominik Pförringer, Chlodwig Kirchhoff, Peter Biberthaler, Karl F Braun, Sebastian Siebenlist
BACKGROUND: Management of distal humeral fractures remains to be one of the most challenging aspects in trauma surgery. Low profile plating systems with variable angle screw fixation represent a crucial advancement to the established angular stable locking plates with considerable attention in current research. The aim of the prospective randomized trial was to review the preliminary results and patients' outcome following treatment with these newly developed implants and to rule out potential differences in fracture treatment of two different plating systems...
December 28, 2017: BMC Musculoskeletal Disorders
Zhe Wang, Yanfei Zeng, Zhendong Zhang, Songbai Sheng, Ju Tian, Rongling Wu, Xiaoming Pang
There is evidence that a band of dry climate separated plants in East Asia into distinct northern and southern groups. However, few studies have focused on the arid belt in this region, especially with regard to plants. We analyzed genetic variation in 22 populations of Siberian apricot ( Prunus sibirica L.), a temperate deciduous species distributed in this arid belt, using two chloroplast DNA (cpDNA) sequences, seven chloroplast microsatellite loci (cpSSRs), and 31 nuclear microsatellite loci (nSSRs), to study its phylogeography...
2017: Frontiers in Plant Science
Yuanqian Gao, Jinhua Li, Jianmin Li, Shuxin Wang
BACKGROUND: The stereo laparoscope is an important tool for achieving depth perception in robot-assisted minimally invasive surgery (MIS). METHODS: A dynamic convergence accommodation algorithm is proposed to improve the viewing experience and achieve accurate depth perception. Based on the principle of the human vision system, a positional kinematic model of the binocular view system is established. The imaging plane pair is rectified to ensure that the two rectified virtual optical axes intersect at the fixation target to provide immersive depth perception...
October 19, 2017: International Journal of Medical Robotics + Computer Assisted Surgery: MRCAS
Gregory D Marquart, Kathryn M Tabor, Eric J Horstick, Mary Brown, Alexandra K Geoca, Nicholas F Polys, Damian Dalle Nogare, Harold A Burgess
Atlases provide a framework for spatially mapping information from diverse sources into a common reference space. Specifically, brain atlases allow annotation of gene expression, cell morphology, connectivity, and activity. In larval zebrafish, advances in genetics, imaging, and computational methods now allow the collection of such information brain-wide. However, due to technical considerations, disparate datasets may use different references and may not be aligned to the same coordinate space. Two recent larval zebrafish atlases exemplify this problem: Z-Brain, containing gene expression, neural activity, and neuroanatomical segmentations, was acquired using immunohistochemical stains, while the Zebrafish Brain Browser (ZBB) was constructed from live scans of fluorescent reporters in transgenic larvae...
August 1, 2017: GigaScience
Monika Wipf, Siegfried Priglinger, Anja Palmowski-Wolfe
INTRODUCTION: In esotropia with larger angles > near than at distance, splitting of the medial rectus muscle has been suggested as a treatment option. Previous reports of bilateral medial rectus Y-splitting as a first intervention showed a reduction of the distance/near disparity with fewer side effects compared to posterior fixation surgery. We address whether a medial rectus Y-splitting as a secondary and/or a unilateral procedure also reduce distance/near disparity. MATERIALS AND METHODS: We retrospectively reviewed the charts of four patients undergoing Y-split recession as a second and/or unilateral surgery...
2017: Journal of Ophthalmology
L de Meij, M A J Telleman, M R C Luijten, J R Polling, M Gutter
PURPOSE: Fixation disparity (FD) is a small misalignment of the eyes within the normal alignment when viewing under binocular condition. Ogle's apparatus measures FD. Standards of procedures vary, which may lead to different outcomes. METHODS: Students with normal ocular alignment, stereopsis ≤60 seconds of arc and visual acuity <0.1 logMAR, were included in this prospective comparative study. Four procedures (P1-P4) of measuring FD with Ogle's apparatus were performed with divergent placement of the line (P1 and P3), or the line moving from subjective zero (P1 and P2: prisms of ascending strength; P3 and P4: prisms alternating base in base out; combined and P4)...
September 2017: Strabismus
Emily B Gaillard, Melissa D Gaillard, Thomas P Gross
BACKGROUND: Women seeking surgical intervention for their hip disorders will often find total hip arthroplasty (THA) presented as their only option. THA, when compared with hip resurfacing arthroplasty, removes substantially more bone-stock, limits range-of-motion, exhibits increased dislocation risk, and presents greater overall 10-year mortality rate. Despite these risks, most surgeons continue to select against women for hip resurfacing because registries notoriously report inferior survivorship when compared with men and THA...
November 2017: Journal of Arthroplasty
Yi-Ting Hsiao, Richard Shillcock, Mateo Obregón, Hamutal Kreiner, Matthew A J Roberts, Scott McDonald
We explore two aspects of exovergence: we test whether smaller binocular fixation disparities accompany the shorter saccades and longer fixations observed in reading Chinese; we test whether potentially advantageous psychophysical effects of exovergence (cf. Arnold & Schindel, 2010; Kersten & Murray, 2010) transfer to text reading. We report differential exovergence in reading Chinese and English: Chinese readers begin fixations with more binocular disparity, but end fixations with a disparity closely similar to that of the English readers...
July 11, 2017: Quarterly Journal of Experimental Psychology: QJEP
Adam Driesman, Siddharth A Mahure, Albit Paoli, Christian A Pean, Sanjit R Konda, Kenneth A Egol
OBJECTIVES: To determine whether racial or economic disparities are associated with short-term complications and outcomes in tibial plateau fracture care. DESIGN: Retrospective cohort study. SETTING: All New York State hospital admissions from 2000 to 2014, as recorded by the New York Statewide Planning and Research Cooperative System database. PATIENTS/PARTICIPANTS: Thirteen thousand five hundred eighteen inpatients with isolated tibial plateau fractures (OTA/AO 44), stratified in 4 groups: white, African American, Hispanic, and other...
October 2017: Journal of Orthopaedic Trauma
J Alberti, J Cebrian, F Alvarez, M Escapa, K S Esquius, E Fanjul, E L Sparks, B Mortazavi, O Iribarne
Altered nutrient cycles and consumer populations are among the top anthropogenic influences on ecosystems. However, studies on the simultaneous impacts of human-driven environmental alterations on ecosystem functions, and the overall change in system multifunctionality are scarce. We used estuarine tidal flats to study the effects of changes in herbivore density and nutrient availability on benthic microalgae (diversity, abundance and biomass) and ecosystem functions (N2-fixation, denitrification, extracellular polymeric substances -EPS- as a proxy for sediment cohesiveness, sediment water content as a proxy of water retention capacity and sediment organic matter)...
June 1, 2017: Scientific Reports
Tara L Alvarez, Eun H Kim, Bérangère Granger-Donetti
People develop presbyopia as part of the normal aging process. Most presbyopes adapt to progressive additive lens (PALs), while others do not. This investigation sought to determine whether the ability to modify disparity vergence or phoria was correlated to PALs adaptation. In experiment 1, a double-step paradigm quantified the ability to modify convergence responses in sixteen presbyopes. In experiment 2, thirty-one incipient presbyopes participated in a 5-minute sustained fixation task to evoke phoria adaptation where the magnitude and rate of phoria adaptation were measured...
May 31, 2017: Scientific Reports
Holly E Holmes, Nick M Powell, Da Ma, Ozama Ismail, Ian F Harrison, Jack A Wells, Niall Colgan, James M O'Callaghan, Ross A Johnson, Tracey K Murray, Zeshan Ahmed, Morten Heggenes, Alice Fisher, M Jorge Cardoso, Marc Modat, Michael J O'Neill, Emily C Collins, Elizabeth M C Fisher, Sébastien Ourselin, Mark F Lythgoe
With increasingly large numbers of mouse models of human disease dedicated to MRI studies, compromises between in vivo and ex vivo MRI must be fully understood in order to inform the choice of imaging methodology. We investigate the application of high resolution in vivo and ex vivo MRI, in combination with tensor-based morphometry (TBM), to uncover morphological differences in the rTg4510 mouse model of tauopathy. The rTg4510 mouse also offers a novel paradigm by which the overexpression of mutant tau can be regulated by the administration of doxycycline, providing us with a platform on which to investigate more subtle alterations in morphology with morphometry...
2017: Frontiers in Neuroinformatics
Kate B Savoie, Marielena Bachier-Rodriguez, Elleson Schurtz, Elizabeth A Tolley, Dana Giel, Alexander Feliz
OBJECTIVE: To assess regional practices in management of cryptorchidism with regard to timely fixation by the current recommended age of 18 months. STUDY DESIGN: A retrospective study was performed. Charts of all patients who underwent surgical correction for cryptorchidism by a pediatric general surgeon or urologist within a tertiary pediatric hospital in an urban setting were systematically reviewed. RESULTS: We identified 1209 patients with cryptorchidism...
June 2017: Journal of Pediatrics
Andrea Canessa, Agostino Gibaldi, Manuela Chessa, Marco Fato, Fabio Solari, Silvio P Sabatini
Binocular stereopsis is the ability of a visual system, belonging to a live being or a machine, to interpret the different visual information deriving from two eyes/cameras for depth perception. From this perspective, the ground-truth information about three-dimensional visual space, which is hardly available, is an ideal tool both for evaluating human performance and for benchmarking machine vision algorithms. In the present work, we implemented a rendering methodology in which the camera pose mimics realistic eye pose for a fixating observer, thus including convergent eye geometry and cyclotorsion...
March 28, 2017: Scientific Data
Agostino Gibaldi, Andrea Canessa, Silvio P Sabatini
Depth perception in near viewing strongly relies on the interpretation of binocular retinal disparity to obtain stereopsis. Statistical regularities of retinal disparities have been claimed to greatly impact on the neural mechanisms that underlie binocular vision, both to facilitate perceptual decisions and to reduce computational load. In this paper, we designed a novel and unconventional approach in order to assess the role of fixation strategy in conditioning the statistics of retinal disparity. We integrated accurate realistic three-dimensional models of natural scenes with binocular eye movement recording, to obtain accurate ground-truth statistics of retinal disparity experienced by a subject in near viewing...
March 20, 2017: Scientific Reports
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