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Fixation disparity

Rumi Hisakata, Daisuke Hayashi, Ikuya Murakami
The static envelope of a Gabor patch with a moving sinusoidal carrier appears shifted in the direction of the carrier motion (De Valois & De Valois, 1991). This phenomenon is called motion-induced position shift. Although several motion-processing stages, ranging from low- to high-level processes, may contribute to position estimation, it is unknown whether a binocular matching stage or an even earlier stage exerts an influence. To elucidate this matter, we investigated the disparity tuning of this illusion by manipulating the binocular disparities of the carrier and the envelope...
October 1, 2016: Journal of Vision
Asad Mohammadzadeh, Adel Spotin, Mahmoud Mahami-Oskouei, Ali Haghighi, Nozhat Zebardast, Kobra Kohansal
In the microevolutionary scales of Entamoeba isolates, the gene migration shows how Entamoeba spp. has epidemiologically drifted among border countries. Five hundred fecal samples were taken from patients suffering gastrointestinal disorders, abdominal pain, and diarrhea at Saggez, northwest Iran located within the border Iraq country. Following parasitological techniques, DNA samples were extracted and amplified by polymerase chain reaction (PCR) of 18S rRNA region to identify Entamoeba infections. To distinguish the Entamoeba spp...
October 20, 2016: Parasitology Research
S Sabharwal, N K Patel, D Griffiths, T Athanasiou, C M Gupte, P Reilly
OBJECTIVES: The objective of this study was to perform a meta-analysis of all randomised controlled trials (RCTs) comparing surgical and non-surgical management of fractures of the proximal humerus, and to determine whether further analyses based on complexity of fracture, or the type of surgical intervention, produced disparate findings on patient outcomes. METHODS: A systematic review of the literature was performed identifying all RCTs that compared surgical and non-surgical management of fractures of the proximal humerus...
October 2016: Bone & Joint Research
Heba M Fouad, Mohamad A Abdelhakim, Ahmed Awadein, Hala Elhilali
PURPOSE: To compare the outcomes of medial rectus (MR) muscle pulley fixation and augmented recession in children with convergence excess esotropia and variable-angle infantile esotropia. METHODS: This was a prospective randomized interventional study in which children with convergence excess esotropia or variable-angle infantile esotropia were randomly allocated to either augmented MR muscle recession (augmented group) or MR muscle pulley posterior fixation (pulley group)...
September 16, 2016: Journal of AAPOS: the Official Publication of the American Association for Pediatric Ophthalmology and Strabismus
Iraklis Pappas, Paul J Chirik
The hydrogenolysis of titanium-nitrogen bonds in a series of bis(cyclopentadienyl) titanium amides, hydrazides and imides by proton coupled electron transfer (PCET) is described. Twelve different N-H bond dissociation free energies (BDFEs) among the various nitrogen-containing ligands were measured or calculated, and effects of metal oxidation state and N-ligand substituent were determined. Two metal hydride complexes, (η(5)-C5Me5)(py-Ph)Rh-H (py-Ph = 2-pyridylphenyl, [Rh]-H) and (η(5)-C5R5)(CO)3Cr-H ([Cr](R)-H, R= H, Me) were evaluated for formal H atom transfer reactivity and were selected due to their relatively weak M-H bond strengths yet ability to activate and cleave molecular hydrogen...
October 3, 2016: Journal of the American Chemical Society
Sid Henriksen, Jenny C A Read, Bruce G Cumming
UNLABELLED: Human stereopsis can operate in dense "cyclopean" images containing no monocular objects. This is believed to depend on the computation of binocular correlation by neurons in primary visual cortex (V1). The observation that humans perceive depth in half-matched random-dot stereograms, although these stimuli have no net correlation, has led to the proposition that human depth perception in these stimuli depends on a distinct "matching" computation possibly performed in extrastriate cortex...
August 24, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Julius Bishop, Arthur Yang, Michael Githens, Alex H S Sox
BACKGROUND: Recent evidence supports total hip arthroplasty (THA) as compared to hemiarthroplasty (HA) for the management of displaced femoral neck fractures in a significant subset of elderly patients. The purpose of this study was to examine trends in femoral neck fracture management over the last 12 years. METHODS: Using the National Inpatient Sample database, we identified patients treated for femoral neck fractures between 1998 and 2010 with THA, HA, or internal fixation (IF)...
September 2016: Geriatric Orthopaedic Surgery & Rehabilitation
Jeffrey P Mullin, Breanna Perlmutter, Eric Schmidt, Edward Benzel, Michael P Steinmetz
OBJECTIVE In 2009, Santoni and colleagues described a novel technique of posterior instrumentation; the cortical bone trajectory (CBT) was described as a caudocephalad and medial-to-lateral trajectory. Reported indications for CBT fixation include patients with osteoporosis, single-level degenerative disease, or adjacent-segment disease (ASD). In cases of revision surgery, it is technically possible and beneficial to place a traditional pedicle screw and a CBT screw at the same spinal level and side. It remains unclear as to the feasibility of placing both a traditional and a CBT screw at all levels of the lumbar spine and with varying trajectories of the preexisting traditional pedicle screws...
July 8, 2016: Journal of Neurosurgery. Spine
Adrien Chopin, Dennis Levi, David Knill, Daphne Bavelier
There has been a long-standing debate about the mechanisms underlying the perception of stereoscopic depth and the computation of the relative disparities that it relies on. Relative disparities between visual objects could be computed in two ways: (a) using the difference in the object's absolute disparities (Hypothesis 1) or (b) using relative disparities based on the differences in the monocular separations between objects (Hypothesis 2). To differentiate between these hypotheses, we measured stereoscopic discrimination thresholds for lines with different absolute and relative disparities...
June 1, 2016: Journal of Vision
C Bourdy, Y James
We propose the presentation on a stereoscopic screen of the electronic eikonometer tests intended for analysis and measurement of perceptual effects of binocular disparity. These tests, so-called "built-in magnification tests" are constructed according to the same principle as those of preceding eikonometers (disparity variation parameters being included in each test presentation, which allows, for test observation and measurements during the examination, the removing of any intermediate optical system). The images of these tests are presented separately to each eye, according to active or passive stereoscopic screen technology: (1) Ogle Spatial Test to measure aniseikonia; (2) Fixation Disparity test: binocular nonius; (3) retinal correspondence test evaluated by nonius horopter; (4) stereoscopic test using Julesz' random-dot stereograms (RDS)...
May 2016: Journal Français D'ophtalmologie
Matthew B O'Rourke, Matthew P Padula
Since emerging in the late 19(th) century, formaldehyde fixation has become a standard method for preservation of tissues from clinical samples. The advantage of formaldehyde fixation is that fixed tissues can be stored at room temperature for decades without concern for degradation. This has led to the generation of huge tissue banks containing thousands of clinically significant samples. Here we review techniques for proteomic analysis of formalin-fixed, paraffin-embedded (FFPE) tissue samples with a specific focus on the methods used to extract and break formaldehyde crosslinks...
2016: BioTechniques
Michael Kerschnitzki, Anat Akiva, Adi Ben Shoham, Yotam Asscher, Wolfgang Wagermaier, Peter Fratzl, Lia Addadi, Steve Weiner
The uptake and transport of ions from the environment to the site of bone formation is only partially understood and, for the most part, based on disparate observations in different animals. Here we study different aspects of the biomineralization pathways in one system, the rapidly forming long bones of the chicken embryo. We mainly used cryo-fixation and cryo-electron imaging to preserve the often unstable mineral phases in the tissues. We show the presence of surprisingly large amounts of mineral particles located inside membrane-delineated vesicles in the bone forming tissue between the blood vessels and the forming bone surface...
July 2016: Journal of Structural Biology
Momoko Nagai, Akira Ito, Junichi Tajino, Hirotaka Iijima, Shoki Yamaguchi, Xiangkai Zhang, Tomoki Aoyama, Hiroshi Kuroki
An understanding of the articular cartilage degenerative process is necessary for the prevention and treatment of joint disease. The present study aimed to examine how long-term immobilization-induced cartilage degeneration is aggravated by remobilization. Sixty 8-week-old male Wistar rats were used in this study. The unilateral knee joint was immobilized using an external fixator for 8 weeks. The rats were killed at 0 and 3 days, and at 1, 2, 4 and 8 weeks after removing the fixator. After the rats were killed, the maximum knee extension angles were measured...
June 2016: Journal of Anatomy
Jeremy Seppi, Jacek Toczyski, Jeff R Crandall, Jason Kerrigan
OBJECTIVE: The goal of this study was to characterize the rollover crash and to evaluate the repeatability of the Dynamic Rollover Test System (DRoTS) in terms of initial roof-to-ground contact conditions, vehicle kinematics, road reaction forces, and vehicle deformation. METHODS: Four rollover crash tests were performed on 2 pairs of replicate vehicles (2 sedan tests and 2 compact multipurpose van [MPV] tests), instrumented with a custom inertial measurement unit to measure vehicle and global kinematics and string potentiometers to measure pillar deformation time histories...
August 17, 2016: Traffic Injury Prevention
Thomas A Aller, Maria Liu, Christine F Wildsoet
PURPOSE: Most studies have reported only minimal reductions in myopia progression with bifocal or progressive multifocal spectacles, although somewhat larger, although mostly still clinically insignificant, effects have been reported in children with nearpoint esophoria and/or accommodative dysfunctions. The CONTROL study was a 1-year, prospective, randomized, clinical trial of bifocal contact lenses for control of myopia in children with eso fixation disparities at near. METHODS: Eighty-six myopic subjects, aged 8 to 18 years, were enrolled in the study after passing the screening examination...
April 2016: Optometry and Vision Science: Official Publication of the American Academy of Optometry
Murat Arıkan, Guray Togral, Askin Esen Hasturk, Fevzi Kekec, Murat Parpucu, Safak Gungor
In this retrospective study, surgical results of four patients with sacral tumors having disparate pathologic diagnoses, who were treated with partial or total sacrectomy and lumbopelvic stabilization were abstracted. Two patients were treated with partial sacral resection and two patients were treated with total sacrectomy and spinopelvic fixation. Fixation methods included spinopelvic fixation with rods and screws in two cases, reconstruction plate in one case, and fresh frozen allografts in two cases. Fibular allografts used for reconstruction accelerated bony union and enhanced the stability in two cases...
December 2015: Asian Spine Journal
Aiga Švede, Elīna Treija, Wolfgang Jaschinski, Gunta Krūmiņa
When measuring fixation disparity (an oculomotor vergence error), the question arises as to whether a monocular or binocular calibration is more precise and physiologically more appropriate. In monocular calibrations, a single eye fixates on a calibration target that is taken as having been projected onto the center of the fovea; the corresponding vergence state represents the heterophoria (the resting vergence position), which has no effect on the calibration procedure. In binocular calibrations, a vergence error may be present and may affect the subsequent measurement of the fixation disparity during binocular recordings...
2015: Perception
Susana Martinez-Conde, Stephen L Macknik
Alfred Lukyanovich Yarbus (1914-1986) pioneered the study of stabilized retinal images, miniature eye movements, and the cognitive influences that act on visual scanning. Yarbus's studies of these different topics have remained fundamentally disconnected and independent of each other, however. In this review, we propose that Yarbus's various research lines are instead deeply and intrinsically interconnected, as are the small eye movements produced during visual fixation and the large-scale scanning patterns associated with visual exploration of objects and scenes...
2015: Perception
Susanne A M Glimne, Gustaf Öqvist Seimyr, Rune L Brautaset
AIM: Since an interaction between binocular disparity and the vergence system takes place in order to reduce retinal disparity, it is likely that vergence control, as measured with the near point of convergence (NPC), will be better if the target used for measurement has 3-dimensional (3-D) features in its most central parts. The aim of the present study was therefore to investigate if the NPC would give a better result using a fixation target with centrally placed 3-D features when compared with a two-dimensional (2-D) target...
2015: Strabismus
Jacek Turski
We study geometric properties of horopters defined by the criterion of equality of angle. Our primary goal is to derive the precise geometry for anatomically correct horopters. When eyes fixate on points along a curve in the horizontal visual plane for which the vergence remains constant, this curve is the larger arc of a circle connecting the eyes' rotation centers. This isovergence circle is known as the Vieth-Müller circle. We show that, along the isovergence circular arc, there is an infinite family of horizontal horopters formed by circular arcs connecting the nodal points...
February 2016: Vision Research
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