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[en] The concept of the uncertainty principle that position and momentum cannot be simultaneously specified to arbitrary accuracy is somewhat difficult to reconcile with experience. This note describes order-of-magnitude calculations which quantify the inadequacy of human perception with regards to direct observation of the breakdown of the trajectory concept implied by the uncertainty principle. Even with the best optical microscope, human vision is inadequate by three orders of magnitude. 1 figure
[en] To determine the optical coherence tomography (OCT) macular findings after successful scleral buckling in eyes with compromised visual status. Study Design:Descriptive cross-sectional study. Place and Duration of Study:Department of Clinical Ophthalmology, Khyber Institute of Ophthalmic Medical Sciences, Postgraduate Medical Institute, Hayatabad Medical Complex, Peshawar, Pakistan, from February 2015 to November 2016. Methodology:Patients with postoperative best corrected visual acuity (BCVA) less than 6/6, successful scleral buckling, and flat macula clinically, aged 18-70 years, were included. OCT scan (OCT-Spectralis, Heidelberg Engineering, GmbH 69121) of central 30 degrees around fovea was performed three months postoperatively. Foveal detachment, epimacular membrane (EMM) and cystoid macular edema (CME), were studied on OCT after successful buckling surgery in eyes with compromised visual status. Results:A total of 164 eyes of 164 patients (92 males 72 females) were assessed with OCT. Foveal detachment (FD) was present in 54 cases (32.9%), cystoid macular edema (CME) in 30 (18.3%), and epimacular membrane (EMM) in 11 cases (6.7%); while no abnormality was detected in 69 (42.1%) cases on OCT. Conclusion:OCT is very helpful in identifying the cause of limited visual recovery after successful retinal detachment (RD) surgery. (author)
[en] In this paper the authors present the development of a characterization process for microcantilever based spring and force sensor wherein fusion of real-time vision and force feedback is used. The process applies a very small force in micronewtons using MM3A nanomanipulators and senses the corresponding deflection using vision feedback, which produces direct characterization of microcantilever for evaluating its effective spring constant. The same process has been applied to find sensitivity of a microcantilever based force sensor. In the process force feedback values are viewed on a digital storage oscilloscope and once calibrated it is directly proportional to the applied force. By having known deflections (x) on images and known values of force (F) sensed by a force feedback sensor, the spring constant of microcantilever has been found as K = 8.75 μN/μm. Using the same procedure a microcantilever based force sensor has been characterized, the resulting sensitivity of force sensor has been found as 34.35 mV/μN.
[en] Visual field defects are a conglomerate of patterns of visual impairment derived from diseases affecting the optic nerve as it extends from the globe to the visual cortex. They are complex signs requiring perimetry or visual confrontation for delineation and are associated with diverse aetiologies. This review considers the chiasmatic and post-chiasmatic causes of visual disturbances, with an emphasis on magnetic resonance imaging (MRI) techniques. Newer MRI sequences are considered, such as diffusion-tensor imaging. MRI images are correlated with perimetric findings in order to demonstrate localization of lesions in the visual pathway. This may serve as a valuable reference tool to clinicians and radiologists in the early diagnostic process of differentiating causes of various visual field defects in daily practice
[en] Increased requirements for tighter tolerances on assembled target components in complex three-dimensional geometries with only days to assemble complete campaigns require the implementation of a computer-controlled high-precision assembly station. Over the last year, an 11-axis computer-controlled assembly station has been designed and built with custom software to handle the multiple coordinate systems and automatically calculate all relational positions. Preliminary development efforts have also been done to explore the benefit of a machine vision feedback module with a dual-camera viewing system to automate certain basic features like crosshair calibration, component leveling, and component centering.
[en] This patent describes in a fuel assembly grid inspection method. The method comprising the steps of: defining an illuminated inspection field of view; supporting a fuel assembly grid of a design having known standard measurements within the inspection field of view by using a fixture whose portions which project into the field of view to support the grid therein are substantially transparent to the field of view; viewing the grid within the field of view; and recording an image thereof to provide information about the grid from which actual measurements can be calculated and compared to the known standard measurements for the particular grid design
[en] Papers are presented under the following session headings: ceramic composites and functional materials; ceramics, new alloys and functional materials; summary report on the workshop on materials for separation process for Vision 21 systems; and new alloys. A list of attendees is included
[en] Dissecting the genetic basis of adaptive traits is key to our understanding of evolutionary processes. A major and essential step in the study of evolutionary genetics is drawing link between genotype and phenotype, which depends on the difficult process of defining the phenotype at different levels, from functional to organismal. Visual pigments are a key component of the visual system and their evolution could also provide important clues on the evolution of visual sensory system in response to sexual and natural selection. As a system in which genotype can be linked to phenotype. I will use visual pigments and color vision, particularly in birds, as a case of a complex phenotype. I aim to emphasize the difficulties in drawing the genotype-phenotype relationship for complex phenotypes and to highlight the challenges of doing so for color vision. The use of vision-based receiver models to quantify animal colors and patterns is increasingly important in many fields of evolutionary research, spanning studies of mate choice, predation, camouflage and sensory ecology. Given these models impact on evolution and ecology, it is important to provide other researchers with the opportunity to better understand animal vision and the corresponding advantages and limitations of these models.