901 research outputs found
Generation of three-dimensional body-fitted coordinates using hyperbolic partial differential equations
An efficient numerical mesh generation scheme capable of creating orthogonal or nearly orthogonal grids about moderately complex three dimensional configurations is described. The mesh is obtained by marching outward from a user specified grid on the body surface. Using spherical grid topology, grids have been generated about full span rectangular wings and a simplified space shuttle orbiter
Use of a hyperbolic grid generation scheme in simulating supersonic viscous flow about three-dimensional winged configuration
The present paper describes a numerical mesh generation technique to be used with an implicit finite difference method for simulating visous supersonic flow about low-aspect-ratio wing body configurations using a single grid strategy. The computational domain is segmented into multiple regions, with borders located in supersonic areas to avoid the otherwise costly interfacing procedure between adjacent segments. The numerical procedure is applied to calculate the turbulent flow around the shuttle orbiter and a canard projectile at supersonic free stream Mach number
A serious adverse surgical event: Management of suspected HSV-1 keratitis in a donor cornea.
PurposeTo describe the management of a serious adverse event in a patient undergoing penetrating keratoplasty (PK).Case reportA 68-year-old man underwent PK for an aphakic bullous keratopathy following previous complicated cataract surgery. He had no past history of herpetic disease. Storage of the corneoscleral disc in the transport bottle precluded microscopic examination. After placement of the trephined donor cornea on the open eye of the recipient, a large dendritiform geographic ulcer was noted on the donor cornea. A replacement cornea was used after changing potentially contaminated instruments. Intravenous antiviral treatment was commenced intraoperatively to reduce the risk of infection to the central nervous system. Postoperatively, oral and topical antiviral treatment was commenced and 6 months following surgery the patient developed a geographic corneal ulcer at the graft host interface.ConclusionContainers to transport corneoscleral discs should enable microscopic examination by the surgeon prior to use. High dose systemic antivirals may reduce the risk of herpetic disease involving the posterior segment of the eye and neuroretina in the aphakic eye and spread to the central nervous system
Unforgeable Noise-Tolerant Quantum Tokens
The realization of devices which harness the laws of quantum mechanics
represents an exciting challenge at the interface of modern technology and
fundamental science. An exemplary paragon of the power of such quantum
primitives is the concept of "quantum money". A dishonest holder of a quantum
bank-note will invariably fail in any forging attempts; indeed, under
assumptions of ideal measurements and decoherence-free memories such security
is guaranteed by the no-cloning theorem. In any practical situation, however,
noise, decoherence and operational imperfections abound. Thus, the development
of secure "quantum money"-type primitives capable of tolerating realistic
infidelities is of both practical and fundamental importance. Here, we propose
a novel class of such protocols and demonstrate their tolerance to noise;
moreover, we prove their rigorous security by determining tight fidelity
thresholds. Our proposed protocols require only the ability to prepare, store
and measure single qubit quantum memories, making their experimental
realization accessible with current technologies.Comment: 18 pages, 5 figure
El jarro de agua o Las gallinas de la tÃa Marcela : zarzuela para niñas solas, en un acto y en verso
Sólo contiene la letraCopia digital. Valladolid : Junta de Castilla y León. ConsejerÃa de Cultura y Turismo, 2009-201
Identification of Feeder Vessels in Ocular Surface Neoplasia using Indocyanine Green Angiography
Purpose: To evaluate indocyanine green angiography (ICGA) for the identification and characterization of afferent (feeding) and efferent (draining) vessels in patients with ocular surface neoplasia. Materials and Methods: Consecutive patients with biopsy-proven benign, pre-invasive, or invasive ocular surface tumors of the bulbar conjunctiva were included. Patients underwent anterior segment optical coherence tomography, ICGA, and color photography for the evaluation of the thickness, location, number, and diameter of afferent and efferent vessels of the lesions. Results: Twenty-two eyes of 22 patients with papillomas (n = 4), intra-epithelial neoplasia lesion (n = 2) in situ or invasive carcinomas (n = 6), nevus (n = 5), conjunctival melanocytic intra-epithelial neoplasia lesion (n = 1), and in situ or invasive melanomas (n = 4) were investigated. Afferent (feeder) vessels were identified in all lesions. There were fewer afferent (3.1 ± 1.6) than efferent (7.5 ± 3.5) vessels per lesion (p < 0.001) and the mean diameter was smaller for afferent (101 ± 62 μm, 28–281) than efferent vessels (137 ± 51 μm, 31–652; p = 0.017). The number of afferent and efferent vessels was associated with the thickness of the lesion (p = 0.037, p < 0.01). Lesion filling times differed between benign and invasive or pre-invasive lesions (p = 0.018). Conclusions: ICGA is a useful adjunctive in vivo imaging method for the assessment of the vasculature in patients with suspected ocular surface neoplasia
High-coherence semiconductor lasers based on integral high-Q resonators in hybrid Si/III-V platforms
Effect of optically-induced potential on the energy of trapped exciton-polaritons below the condensation threshold
Exciton-polaritons (polaritons herein) offer a unique nonlinear platform for
studies of collective macroscopic quantum phenomena in a solid state system.
Shaping of polariton flow and polariton confinement via potential landscapes
created by nonresonant optical pumping has gained considerable attention due to
the degree of flexibility and control offered by optically-induced potentials.
Recently, large density-dependent energy shifts (blueshifts) exhibited by
optically trapped polaritons at low densities, below the bosonic condensation
threshold, were interpreted as an evidence of strong polariton-polariton
interactions [Nat. Phys. 13, 870 (2017)]. In this work, we further investigate
the origins of these blueshifts in optically-induced circular traps and present
evidence of significant blueshift of the polariton energy due to reshaping of
the optically-induced potential with laser pump power. Our work demonstrates
strong influence of the effective potential formed by an optically-injected
excitonic reservoir on the energy blueshifts observed below and up to the
polariton condensation threshold and suggests that the observed blueshifts
arise due to interaction of polaritons with the excitonic reservoir, rather
than due to polariton-polariton interaction.Comment: 10 pages, 8 figure
A Revised Design for Microarray Experiments to Account for Experimental Noise and Uncertainty of Probe Response
Background
Although microarrays are analysis tools in biomedical research, they are known to yield noisy output that usually requires experimental confirmation. To tackle this problem, many studies have developed rules for optimizing probe design and devised complex statistical tools to analyze the output. However, less emphasis has been placed on systematically identifying the noise component as part of the experimental procedure. One source of noise is the variance in probe binding, which can be assessed by replicating array probes. The second source is poor probe performance, which can be assessed by calibrating the array based on a dilution series of target molecules. Using model experiments for copy number variation and gene expression measurements, we investigate here a revised design for microarray experiments that addresses both of these sources of variance.
Results
Two custom arrays were used to evaluate the revised design: one based on 25 mer probes from an Affymetrix design and the other based on 60 mer probes from an Agilent design. To assess experimental variance in probe binding, all probes were replicated ten times. To assess probe performance, the probes were calibrated using a dilution series of target molecules and the signal response was fitted to an adsorption model. We found that significant variance of the signal could be controlled by averaging across probes and removing probes that are nonresponsive or poorly responsive in the calibration experiment. Taking this into account, one can obtain a more reliable signal with the added option of obtaining absolute rather than relative measurements.
Conclusion
The assessment of technical variance within the experiments, combined with the calibration of probes allows to remove poorly responding probes and yields more reliable signals for the remaining ones. Once an array is properly calibrated, absolute quantification of signals becomes straight forward, alleviating the need for normalization and reference hybridizations
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